.dockerignore

@@ -0,0 +1,8 @@
+lego.exe
+.lego
+.gitcookies
+.idea
+.vscode/
+dist/
+builds/
+docs/

.github/FUNDING.yml

@@ -0,0 +1 @@
+github: ldez

.github/ISSUE_TEMPLATE/bug_report.yml

@@ -0,0 +1,104 @@
+name: Bug Report
+description: Create a report to help us improve.
+labels: [bug]
+body:
+  - type: checkboxes
+    id: terms
+    attributes:
+      label: Welcome
+      options:
+        - label: Yes, I'm using a binary release within 2 latest releases.
+          required: true
+        - label: Yes, I've searched similar issues on GitHub and didn't find any.
+          required: true
+        - label: Yes, I've included all information below (version, config, etc).
+          required: true
+
+  - type: textarea
+    id: expected
+    attributes:
+      label: What did you expect to see?
+      placeholder: Description.
+    validations:
+      required: true
+
+  - type: textarea
+    id: current
+    attributes:
+      label: What did you see instead?
+      placeholder: Description.
+    validations:
+      required: true
+
+  - type: dropdown
+    id: type
+    attributes:
+      label: How do you use lego?
+      options:
+        - Library
+        - Binary
+        - Docker image
+        - Through Traefik
+        - Through Caddy
+        - Through Terraform ACME provider
+        - Through Bitnami
+        - Other
+    validations:
+      required: true
+
+  - type: textarea
+    id: steps
+    attributes:
+      label: Reproduction steps
+      description: "How do you trigger this bug? Please walk us through it step by step."
+      placeholder: |
+        1. ...
+        2. ...
+        3. ...
+        ...
+    validations:
+      required: true
+
+  - type: textarea
+    id: version
+    attributes:
+      label: Version of lego
+      description: |-
+        ```console
+        $ lego --version
+        ```
+      placeholder: Paste output here
+      render: console
+    validations:
+      required: true
+
+  - type: textarea
+    id: logs
+    attributes:
+      label: Logs
+      value: |-
+        <details>
+
+        ```console
+        # paste output here
+        ```
+
+        </details>
+    validations:
+      required: true
+
+  - type: textarea
+    id: go-env
+    attributes:
+      label: Go environment (if applicable)
+      value: |-
+        <details>
+
+        ```console
+        $ go version && go env
+        # paste output here
+        ```
+
+        </details>
+    validations:
+      required: false

.github/ISSUE_TEMPLATE/config.yml

@@ -0,0 +1,8 @@
+blank_issues_enabled: false
+contact_links:
+  - name: Questions
+    url: https://github.com/go-acme/lego/discussions
+    about: If you have a question, or are looking for advice, please post on our Discussions section!
+  - name: lego documentation
+    url: https://go-acme.github.io/lego/
+    about: Please take a look to our documentation.

.github/ISSUE_TEMPLATE/feature_request.yml

@@ -0,0 +1,34 @@
+name: Feature request
+description: Suggest an idea for this project.
+body:
+  - type: checkboxes
+    id: terms
+    attributes:
+      label: Welcome
+      options:
+        - label: Yes, I've searched similar issues on GitHub and didn't find any.
+          required: true
+
+  - type: dropdown
+    id: type
+    attributes:
+      label: How do you use lego?
+      options:
+        - Library
+        - Binary
+        - Docker image
+        - Through Traefik
+        - Through Caddy
+        - Through Terraform ACME provider
+        - Through Bitnami
+        - Other
+    validations:
+      required: true
+
+  - type: textarea
+    id: description
+    attributes:
+      label: Detailed Description
+      placeholder: Description.
+    validations:
+      required: true

.github/ISSUE_TEMPLATE/new_dns_provider.yml

@@ -0,0 +1,60 @@
+name: New DNS provider support
+description: Request for the support of a new DNS provider.
+title: "Support for provider: <put the name of your provider>"
+labels: [enhancement, new-provider]
+body:
+  - type: checkboxes
+    id: terms
+    attributes:
+      label: Welcome
+      options:
+        - label: Yes, I've searched similar issues on GitHub and didn't find any.
+          required: true
+        - label: Yes, the DNS provider exposes a public API.
+          required: true
+        - label: Yes, I know that the lego maintainers don't have an account in all DNS providers in the world.
+          required: true
+        - label: Yes, I'm able to create a pull request and be able to maintain the implementation.
+          required: false
+        - label: Yes, I'm able to test an implementation if someone creates a pull request to add the support of this DNS provider.
+          required: false
+
+  - type: dropdown
+    id: type
+    attributes:
+      label: How do you use lego?
+      options:
+        - Library
+        - Binary
+        - Docker image
+        - Through Traefik
+        - Through Caddy
+        - Through Terraform ACME provider
+        - Through Bitnami
+        - Other
+    validations:
+      required: true
+
+  - type: input
+    id: provider-link
+    attributes:
+      label: Link to the DNS provider
+      placeholder: Put your link here.
+    validations:
+      required: true
+
+  - type: input
+    id: api-link
+    attributes:
+      label:  Link to the API documentation
+      placeholder: Put your link here.
+    validations:
+      required: true
+
+  - type: textarea
+    id: expected
+    attributes:
+      label: Additional Notes
+      placeholder: Your notes.
+    validations:
+      required: false

.github/workflows/documentation.yml

@@ -0,0 +1,50 @@
+name: Documentation
+
+on:
+  push:
+    branches:
+      - master
+
+jobs:
+
+  doc:
+    name: Build and deploy documentation
+    runs-on: ubuntu-latest
+    env:
+      GO_VERSION: '1.20'
+      HUGO_VERSION: 0.101.0
+      CGO_ENABLED: 0
+
+    steps:
+
+      # https://github.com/marketplace/actions/setup-go-environment
+      - name: Set up Go ${{ env.GO_VERSION }}
+        uses: actions/setup-go@v3
+        with:
+          go-version: ${{ env.GO_VERSION }}
+
+      # https://github.com/marketplace/actions/checkout
+      - name: Check out code
+        uses: actions/checkout@v3
+        with:
+          fetch-depth: 0
+
+      - name: Generate DNS docs
+        run: make generate-dns
+
+      - name: Install Hugo
+        run: |
+          wget -O /tmp/hugo.deb https://github.com/gohugoio/hugo/releases/download/v${HUGO_VERSION}/hugo_${HUGO_VERSION}_Linux-64bit.deb
+          sudo dpkg -i /tmp/hugo.deb
+
+      - name: Build Documentation
+        run: make docs-build
+
+      # https://github.com/marketplace/actions/github-pages
+      - name: Deploy to GitHub Pages
+        uses: crazy-max/ghaction-github-pages@v3
+        with:
+          target_branch: gh-pages
+          build_dir: docs/public
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

.github/workflows/go-cross.yml

@@ -0,0 +1,55 @@
+name: Go Matrix
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+
+jobs:
+
+  cross:
+    name: Go
+    runs-on: ${{ matrix.os }}
+    env:
+      CGO_ENABLED: 0
+
+    strategy:
+      matrix:
+        go-version: [ '1.19', '1.20', 1.x ]
+        os: [ubuntu-latest, macos-latest, windows-latest]
+
+    steps:
+      # https://github.com/marketplace/actions/setup-go-environment
+      - name: Set up Go ${{ matrix.go-version }}
+        uses: actions/setup-go@v3
+        with:
+          go-version: ${{ matrix.go-version }}
+
+      # https://github.com/marketplace/actions/checkout
+      - name: Checkout code
+        uses: actions/checkout@v3
+
+      # https://github.com/marketplace/actions/cache
+      - name: Cache Go modules
+        uses: actions/cache@v3
+        with:
+          # In order:
+          # * Module download cache
+          # * Build cache (Linux)
+          # * Build cache (Mac)
+          # * Build cache (Windows)
+          path: |
+            ~/go/pkg/mod
+            ~/.cache/go-build
+            ~/Library/Caches/go-build
+            %LocalAppData%\go-build
+          key: ${{ runner.os }}-${{ matrix.go-version }}-go-${{ hashFiles('**/go.sum') }}
+          restore-keys: |
+            ${{ runner.os }}-${{ matrix.go-version }}-go-
+
+      - name: Test
+        run: go test -v -cover ./...
+
+      - name: Build
+        run: go build -v -ldflags "-s -w" -trimpath -o ./dist/lego ./cmd/lego/

.github/workflows/pr.yml

@@ -0,0 +1,85 @@
+name: Main
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+
+jobs:
+
+  main:
+    name: Main Process
+    runs-on: ubuntu-latest
+    env:
+      GO_VERSION: '1.20'
+      GOLANGCI_LINT_VERSION: v1.53.1
+      HUGO_VERSION: 0.54.0
+      CGO_ENABLED: 0
+      LEGO_E2E_TESTS: CI
+      MEMCACHED_HOSTS: localhost:11211
+
+    steps:
+
+      # https://github.com/marketplace/actions/setup-go-environment
+      - name: Set up Go ${{ env.GO_VERSION }}
+        uses: actions/setup-go@v3
+        with:
+          go-version: ${{ env.GO_VERSION }}
+
+      # https://github.com/marketplace/actions/checkout
+      - name: Check out code
+        uses: actions/checkout@v3
+        with:
+          fetch-depth: 0
+
+      # https://github.com/marketplace/actions/cache
+      - name: Cache Go modules
+        uses: actions/cache@v3
+        with:
+          path: ~/go/pkg/mod
+          key: ${{ runner.os }}-go-${{ hashFiles('**/go.sum') }}
+          restore-keys: |
+            ${{ runner.os }}-go-
+
+      - name: Check and get dependencies
+        run: |
+          go mod tidy
+          git diff --exit-code go.mod
+          git diff --exit-code go.sum
+
+      # https://golangci-lint.run/usage/install#other-ci
+      - name: Install golangci-lint ${{ env.GOLANGCI_LINT_VERSION }}
+        run: |
+          curl -sSfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh | sh -s -- -b $(go env GOPATH)/bin ${GOLANGCI_LINT_VERSION}
+          golangci-lint --version
+
+      - name: Install Pebble
+        run: go install github.com/letsencrypt/pebble/v2/cmd/pebble@main
+
+      - name: Install challtestsrv
+        run: go install github.com/letsencrypt/pebble/v2/cmd/pebble-challtestsrv@main
+
+      - name: Set up a Memcached server
+        uses: niden/actions-memcached@v7
+
+      - name: Setup /etc/hosts
+        run: |
+          echo "127.0.0.1 acme.wtf" | sudo tee -a /etc/hosts
+          echo "127.0.0.1 lego.wtf" | sudo tee -a /etc/hosts
+          echo "127.0.0.1 acme.lego.wtf" | sudo tee -a /etc/hosts
+          echo "127.0.0.1 légô.wtf" | sudo tee -a /etc/hosts
+          echo "127.0.0.1 xn--lg-bja9b.wtf" | sudo tee -a /etc/hosts
+
+      - name: Make
+        run: |
+          make
+          make clean
+
+      - name: Install Hugo
+        run: |
+          wget -O /tmp/hugo.deb https://github.com/gohugoio/hugo/releases/download/v${HUGO_VERSION}/hugo_${HUGO_VERSION}_Linux-64bit.deb
+          sudo dpkg -i /tmp/hugo.deb
+
+      - name: Build Documentation
+        run: make docs-build

.github/workflows/release.yml

@@ -0,0 +1,63 @@
+name: Release
+
+on:
+  push:
+    tags:
+      - v*
+
+jobs:
+
+  release:
+    name: Release version
+    runs-on: ubuntu-latest
+    env:
+      GO_VERSION: '1.20'
+      CGO_ENABLED: 0
+
+    steps:
+
+      # https://github.com/marketplace/actions/free-disk-space-ubuntu
+      - name: Free Disk Space
+        uses: jlumbroso/free-disk-space@main
+        with:
+          # this might remove tools that are actually needed
+          tool-cache: false
+
+          # all of these default to true
+          android: true
+          dotnet: true
+          haskell: true
+          large-packages: true
+          docker-images: true
+          swap-storage: false
+
+      - name: Check out code
+        uses: actions/checkout@v3
+        with:
+          fetch-depth: 0
+
+      - name: Set up Go ${{ env.GO_VERSION }}
+        uses: actions/setup-go@v4
+        with:
+          go-version: ${{ env.GO_VERSION }}
+
+      - name: Docker Login
+        env:
+          DOCKER_USERNAME: ${{ secrets.DOCKER_USERNAME }}
+          DOCKER_PASSWORD: ${{ secrets.DOCKER_PASSWORD }}
+        run: echo "${DOCKER_PASSWORD}" | docker login --username "${DOCKER_USERNAME}" --password-stdin
+
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v2
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v2
+
+      # https://goreleaser.com/ci/actions/
+      - name: Run GoReleaser
+        uses: goreleaser/goreleaser-action@v4
+        with:
+          version: latest
+          args: release -p 1 --clean --timeout=90m
+        env:
+          GITHUB_TOKEN: ${{ secrets.GH_TOKEN_REPO }}

.gitignore

@@ -0,0 +1,6 @@
+.lego
+.gitcookies
+.idea
+.vscode/
+dist/
+builds/

.golangci.yml

@@ -0,0 +1,225 @@
+run:
+  timeout: 10m
+  skip-files: []
+
+linters-settings:
+  govet:
+    check-shadowing: true
+  gocyclo:
+    min-complexity: 12
+  maligned:
+    suggest-new: true
+  goconst:
+    min-len: 3
+    min-occurrences: 3
+  funlen:
+    lines: -1
+    statements: 50
+  misspell:
+    locale: US
+    ignore-words:
+      - internetbs
+  depguard:
+    rules:
+      main:
+        deny:
+          - pkg: "github.com/instana/testify"
+            desc: not allowed
+          - pkg: "github.com/pkg/errors"
+            desc: Should be replaced by standard lib errors package
+  tagalign:
+    align: false
+    order:
+      - xml
+      - json
+      - yaml
+      - yml
+      - toml
+      - mapstructure
+      - url
+  godox:
+    keywords:
+      - FIXME
+  gocritic:
+    enabled-tags:
+      - diagnostic
+      - style
+      - performance
+    disabled-checks:
+      - paramTypeCombine # already handle by gofumpt.extra-rules
+      - whyNoLint # already handle by nonolint
+      - unnamedResult
+      - hugeParam
+      - sloppyReassign
+      - rangeValCopy
+      - octalLiteral
+      - ptrToRefParam
+      - appendAssign
+      - ruleguard
+      - httpNoBody
+      - exposedSyncMutex
+  revive:
+    rules:
+      - name: struct-tag
+      - name: blank-imports
+      - name: context-as-argument
+      - name: context-keys-type
+      - name: dot-imports
+      - name: error-return
+      - name: error-strings
+      - name: error-naming
+      - name: exported
+        disabled: true
+      - name: if-return
+      - name: increment-decrement
+      - name: var-naming
+      - name: var-declaration
+      - name: package-comments
+        disabled: true
+      - name: range
+      - name: receiver-naming
+      - name: time-naming
+      - name: unexported-return
+      - name: indent-error-flow
+      - name: errorf
+      - name: empty-block
+      - name: superfluous-else
+      - name: unused-parameter
+        disabled: true
+      - name: unreachable-code
+      - name: redefines-builtin-id
+
+linters:
+  enable-all: true
+  disable:
+    - deadcode # deprecated
+    - exhaustivestruct # deprecated
+    - golint # deprecated
+    - ifshort # deprecated
+    - interfacer # deprecated
+    - maligned # deprecated
+    - nosnakecase # deprecated
+    - scopelint # deprecated
+    - structcheck # deprecated
+    - varcheck # deprecated
+    - cyclop # duplicate of gocyclo
+    - sqlclosecheck # not relevant (SQL)
+    - rowserrcheck # not relevant (SQL)
+    - execinquery # not relevant (SQL)
+    - lll
+    - gosec
+    - dupl # not relevant
+    - prealloc # too many false-positive
+    - bodyclose # too many false-positive
+    - gomnd
+    - testpackage # not relevant
+    - tparallel # not relevant
+    - paralleltest # not relevant
+    - nestif # too many false-positive
+    - wrapcheck
+    - goerr113 # not relevant
+    - nlreturn # not relevant
+    - wsl # not relevant
+    - exhaustive # not relevant
+    - exhaustruct # not relevant
+    - makezero # not relevant
+    - forbidigo
+    - varnamelen # not relevant
+    - nilnil # not relevant
+    - ireturn # not relevant
+    - contextcheck # too many false-positive
+    - tenv # we already have a test "framework" to handle env vars
+    - noctx
+    - forcetypeassert
+    - tagliatelle
+    - errname
+    - errchkjson
+    - nonamedreturns
+    - musttag # false-positive https://github.com/junk1tm/musttag/issues/17
+    - gosmopolitan  # not relevant
+
+issues:
+  exclude-use-default: false
+  max-per-linter: 0
+  max-same-issues: 0
+  exclude:
+    - 'Error return value of .((os\.)?std(out|err)\..*|.*Close|.*Flush|os\.Remove(All)?|.*printf?|os\.(Un)?Setenv). is not checked'
+    - 'exported (type|method|function) (.+) should have comment or be unexported'
+    - 'ST1000: at least one file in a package should have a package comment'
+  exclude-rules:
+    - path: (.+)_test.go
+      linters:
+        - funlen
+        - goconst
+        - maintidx
+    - path: providers/dns/dns_providers.go
+      linters:
+        - gocyclo
+    - path: providers/dns/gcloud/googlecloud_test.go
+      text: 'string `(lego\.wtf|manhattan)` has (\d+) occurrences, make it a constant'
+    - path: providers/dns/zoneee/zoneee_test.go
+      text: 'string `(bar|foo)` has (\d+) occurrences, make it a constant'
+    - path: certcrypto/crypto.go
+      text: '(tlsFeatureExtensionOID|ocspMustStapleFeature) is a global variable'
+    - path: challenge/dns01/nameserver.go
+      text: '(defaultNameservers|recursiveNameservers|fqdnSoaCache|muFqdnSoaCache) is a global variable'
+    - path: challenge/dns01/nameserver_.+.go
+      text: 'dnsTimeout is a global variable'
+    - path: challenge/dns01/nameserver_test.go
+      text: 'findXByFqdnTestCases is a global variable'
+    - path: challenge/http01/domain_matcher.go
+      text: 'string `Host` has \d occurrences, make it a constant'
+    - path: challenge/http01/domain_matcher.go
+      text: 'cyclomatic complexity \d+ of func `parseForwardedHeader` is high'
+    - path: challenge/http01/domain_matcher.go
+      text: "Function 'parseForwardedHeader' has too many statements"
+    - path: challenge/tlsalpn01/tls_alpn_challenge.go
+      text: 'idPeAcmeIdentifierV1 is a global variable'
+    - path: log/logger.go
+      text: 'Logger is a global variable'
+    - path: 'e2e/(dnschallenge/)?[\d\w]+_test.go'
+      text: load is a global variable
+    - path: 'providers/dns/([\d\w]+/)*[\d\w]+_test.go'
+      text: 'envTest is a global variable'
+    - path: providers/dns/namecheap/namecheap_test.go
+      text: 'testCases is a global variable'
+    - path: providers/dns/acmedns/acmedns_test.go
+      text: 'egTestAccount is a global variable'
+    - path: providers/http/memcached/memcached_test.go
+      text: 'memcachedHosts is a global variable'
+    - path: providers/dns/sakuracloud/client_test.go
+      text: 'cyclomatic complexity 13 of func `(TestDNSProvider_cleanupTXTRecord_concurrent|TestDNSProvider_addTXTRecord_concurrent)` is high'
+    - path: providers/dns/dns_providers.go
+      text: "Function 'NewDNSChallengeProviderByName' has too many statements"
+    - path: cmd/flags.go
+      text: "Function 'CreateFlags' is too long"
+    - path: certificate/certificates.go
+      text: "Function 'GetOCSP' is too long"
+    - path: providers/dns/otc/client.go
+      text: "Function 'loginRequest' is too long"
+    - path: providers/dns/gandi/gandi.go
+      text: "Function 'Present' is too long"
+    - path: cmd/zz_gen_cmd_dnshelp.go
+      linters:
+        - gocyclo
+        - funlen
+    - path: providers/dns/checkdomain/internal/types.go
+      text: '`payed` is a misspelling of `paid`'
+    - path: providers/dns/namecheap/namecheap_test.go
+      text: 'cognitive complexity (\d+) of func `TestDNSProvider_getHosts` is high'
+    - path: platform/tester/env_test.go
+      linters:
+        - thelper
+    - path: providers/dns/oraclecloud/oraclecloud_test.go
+      text: 'SA1019: x509.EncryptPEMBlock has been deprecated since Go 1.16'
+    - path: challenge/http01/domain_matcher.go
+      text: 'yodaStyleExpr'
+    - path: providers/dns/dns_providers.go
+      text: 'Function name: NewDNSChallengeProviderByName,'
+    - path: providers/dns/sakuracloud/wrapper.go
+      text: 'mu is a global variable'
+    - path: providers/dns/hosttech/internal/client_test.go
+      text: 'Duplicate words \(0\) found'
+    - path: cmd/cmd_renew.go
+      text: 'cyclomatic complexity 16 of func `renewForDomains` is high'
+

.goreleaser.yml

@@ -0,0 +1,135 @@
+project_name: lego
+
+builds:
+  - binary: lego
+
+    main: ./cmd/lego/main.go
+    env:
+      - CGO_ENABLED=0
+    flags:
+      - -trimpath
+    ldflags:
+      - -s -w -X main.version={{.Version}}
+
+    goos:
+      - windows
+      - darwin
+      - linux
+      - freebsd
+      - openbsd
+      - solaris
+    goarch:
+      - amd64
+      - 386
+      - arm
+      - arm64
+      - mips
+      - mipsle
+      - mips64
+      - mips64le
+    goarm:
+      - 7
+      - 6
+      - 5
+    gomips:
+      - hardfloat
+      - softfloat
+
+    ignore:
+      - goos: darwin
+        goarch: 386
+      - goos: openbsd
+        goarch: arm
+
+archives:
+  - id: lego
+    name_template: '{{ .ProjectName }}_v{{ .Version }}_{{ .Os }}_{{ .Arch }}{{ if .Arm }}v{{ .Arm }}{{ end }}{{ if .Mips }}_{{ .Mips }}{{ end }}'
+    format: tar.gz
+    format_overrides:
+      - goos: windows
+        format: zip
+    files:
+      - LICENSE
+      - CHANGELOG.md
+
+docker_manifests:
+  - name_template: 'goacme/lego:{{ .Tag }}'
+    image_templates:
+      - 'goacme/lego:{{ .Tag }}-amd64'
+      - 'goacme/lego:{{ .Tag }}-arm64'
+      - 'goacme/lego:{{ .Tag }}-armv7'
+  - name_template: 'goacme/lego:latest'
+    image_templates:
+      - 'goacme/lego:{{ .Tag }}-amd64'
+      - 'goacme/lego:{{ .Tag }}-arm64'
+      - 'goacme/lego:{{ .Tag }}-armv7'
+  - name_template: 'goacme/lego:v{{ .Major }}.{{ .Minor }}'
+    image_templates:
+      - 'goacme/lego:v{{ .Major }}.{{ .Minor }}-amd64'
+      - 'goacme/lego:v{{ .Major }}.{{ .Minor }}-arm64'
+      - 'goacme/lego:v{{ .Major }}.{{ .Minor }}-armv7'
+
+dockers:
+  - use: buildx
+    goos: linux
+    goarch: amd64
+    dockerfile: buildx.Dockerfile
+    image_templates:
+      - 'goacme/lego:latest-amd64'
+      - 'goacme/lego:{{ .Tag }}-amd64'
+      - 'goacme/lego:v{{ .Major }}.{{ .Minor }}-amd64'
+    build_flag_templates:
+      - '--pull'
+      # https://github.com/opencontainers/image-spec/blob/main/annotations.md#pre-defined-annotation-keys
+      - '--label=org.opencontainers.image.title={{.ProjectName}}'
+      - '--label=org.opencontainers.image.description=Lets Encrypt/ACME client and library written in Go'
+      - '--label=org.opencontainers.image.source={{.GitURL}}'
+      - '--label=org.opencontainers.image.url={{.GitURL}}'
+      - '--label=org.opencontainers.image.documentation=https://go-acme.github.io/lego'
+      - '--label=org.opencontainers.image.created={{.Date}}'
+      - '--label=org.opencontainers.image.revision={{.FullCommit}}'
+      - '--label=org.opencontainers.image.version={{.Version}}'
+      - '--platform=linux/amd64'
+
+  - use: buildx
+    goos: linux
+    goarch: arm64
+    dockerfile: buildx.Dockerfile
+    image_templates:
+      - 'goacme/lego:latest-arm64'
+      - 'goacme/lego:{{ .Tag }}-arm64'
+      - 'goacme/lego:v{{ .Major }}.{{ .Minor }}-arm64'
+    build_flag_templates:
+      - '--pull'
+      # https://github.com/opencontainers/image-spec/blob/main/annotations.md#pre-defined-annotation-keys
+      - '--label=org.opencontainers.image.title={{.ProjectName}}'
+      - '--label=org.opencontainers.image.description=Lets Encrypt/ACME client and library written in Go'
+      - '--label=org.opencontainers.image.source={{.GitURL}}'
+      - '--label=org.opencontainers.image.url={{.GitURL}}'
+      - '--label=org.opencontainers.image.documentation=https://go-acme.github.io/lego'
+      - '--label=org.opencontainers.image.created={{.Date}}'
+      - '--label=org.opencontainers.image.revision={{.FullCommit}}'
+      - '--label=org.opencontainers.image.version={{.Version}}'
+      - '--platform=linux/arm64'
+
+  - use: buildx
+    goos: linux
+    goarch: arm
+    goarm: '7'
+    dockerfile: buildx.Dockerfile
+    image_templates:
+      - 'goacme/lego:latest-armv7'
+      - 'goacme/lego:{{ .Tag }}-armv7'
+      - 'goacme/lego:v{{ .Major }}.{{ .Minor }}-armv7'
+    build_flag_templates:
+      - '--pull'
+      # https://github.com/opencontainers/image-spec/blob/main/annotations.md#pre-defined-annotation-keys
+      - '--label=org.opencontainers.image.title={{.ProjectName}}'
+      - '--label=org.opencontainers.image.description=Lets Encrypt/ACME client and library written in Go'
+      - '--label=org.opencontainers.image.source={{.GitURL}}'
+      - '--label=org.opencontainers.image.url={{.GitURL}}'
+      - '--label=org.opencontainers.image.documentation=https://go-acme.github.io/lego'
+      - '--label=org.opencontainers.image.created={{.Date}}'
+      - '--label=org.opencontainers.image.revision={{.FullCommit}}'
+      - '--label=org.opencontainers.image.version={{.Version}}'
+      - '--platform=linux/arm/v7'

CHANGELOG.md

@@ -0,0 +1,999 @@
+# Changelog
+
+## [v4.13.2] - 2023-07-21
+
+### Fixed:
+- **[dnsprovider]** servercow: fix regression
+
+## [v4.13.1] - 2023-07-20
+
+### Added:
+- **[dnsprovider]** Add DNS provider for IPv64
+- **[dnsprovider]** Add DNS provider for Metaname
+- **[dnsprovider]** Add DNS provider for RcodeZero
+- **[dnsprovider]** Add DNS provider for Efficient IP
+- **[dnsprovider]** azure: new implementation based on the new API client
+- **[lib]** Experimental option to force DNS queries to use TCP
+
+### Changed:
+- **[dnsprovider]** cloudflare: update api client to v0.70.0
+
+### Fixed:
+- **[dnsprovider,cname]** fix: ensure case-insensitive comparison of CNAME records
+- **[cli]** fix: list command
+- **[lib]** fix: ARI explanationURL
+
+## [v4.13.0] - 2023-07-20
+
+Cancelled due to a CI issue (no space left on device).
+
+## [v4.12.2] - 2023-06-19
+
+### Fixed:
+- **[dnsprovider]** dnsmadeeasy: fix DeleteRecord
+- **[lib]** fix: read status code from response
+
+## [v4.12.1] - 2023-06-06
+
+### Fixed:
+- **[dnsprovider]** pdns: fix record value
+
+## [v4.12.0] - 2023-05-28
+
+### Added:
+- **[lib,cli]** Initial ACME Renewal Info (ARI) Implementation
+- **[dnsprovider]** Add DNS provider for Derak Cloud
+- **[dnsprovider]** route53: pass ExternalID property to STS:AssumeRole API operation
+- **[lib,cli]** Support custom duration for certificate
+
+### Changed:
+- **[dnsprovider]** Refactor DNS provider and client implementations
+
+### Fixed:
+- **[dnsprovider]** autodns: fixes wrong zone in api call if CNAME is used
+- **[cli]** fix: archive only domain-related files on revoke
+
+## [v4.11.0] - 2023-05-02
+
+### Added:
+- **[lib]** Support for certificate with raw IP SAN (RFC8738)
+- **[dnsprovider]** Add Brandit.com as DNS provider
+- **[dnsprovider]** Add DNS provider for Bunny
+- **[dnsprovider]** Add DNS provider for Nodion
+- **[dnsprovider]** Add Google Domains as DNS provider
+- **[dnsprovider]** Add DNS provider for Plesk
+
+### Changed:
+- **[cli]** feat: add LEGO_CERT_PEM_PATH and LEGO_CERT_PFX_PATH to run hook
+- **[lib,cli]** feat: add RSA 3072
+- **[dnsprovider]** gcloud: update google APIs to latest version
+- **[lib,dnsprovider,cname]** chore: replace GetRecord by GetChallengeInfo
+
+### Fixed:
+- **[dnsprovider]** rimuhosting: fix API base URL
+
+## [v4.10.2] - 2023-02-26
+
+Fix Docker image builds.
+
+## [v4.10.1] - 2023-02-25
+
+### Fixed:
+- **[dnsprovider,cname]** acmedns: fix CNAME support
+- **[dnsprovider]** dynu: fix subdomain support
+
+## [v4.10.0] - 2023-02-10
+
+### Added:
+- **[dnsprovider]** Add DNS provider for dnsHome.de
+- **[dnsprovider]** Add DNS provider for Liara
+- **[dnsprovider]** Add DNS provider for UltraDNS
+- **[dnsprovider]** Add DNS provider for Websupport
+
+### Changed:
+- **[dnsprovider]** ibmcloud: add support for subdomains
+- **[dnsprovider]** infomaniak: CNAME support
+- **[dnsprovider]** namesilo: add cleanup before add a DNS record
+- **[dnsprovider]** route53: Allow static credentials to be supplied
+- **[dnsprovider]** tencentcloud: support punycode domain
+
+### Fixed:
+- **[dnsprovider]** alidns: filter on record type
+- **[dnsprovider]** arvancloud: replace arvancloud.com by arvancloud.ir
+- **[dnsprovider]** hetzner: improve zone ID detection
+- **[dnsprovider]** luadns: removed dot suffix from authzone while searching for zone
+- **[dnsprovider]** pdns: fix usage of notify only when zone kind is Master or Slave
+- **[dnsprovider]** return an error when extracting record name
+
+## [v4.9.1] - 2022-11-25
+
+### Changed:
+- 
+- **[lib,cname]** cname: add log about CNAME entries
+- **[dnsprovider]** regru: improve error handling
+
+### Fixed:
+- 
+- **[dnsprovider,cname]** fix CNAME support for multiple DNS providers
+- **[dnsprovider,cname]** duckdns: fix CNAME support
+- **[dnsprovider,cname]** oraclecloud: use fqdn to resolve zone
+- **[dnsprovider]** hurricane: fix CNAME support
+- **[lib,cname]** cname: stop trying to traverse cname if none have been found
+
+## [v4.9.0] - 2022-10-03
+
+### Added:
+
+- **[dnsprovider]** Add DNS provider for CIVO
+- **[dnsprovider]** Add DNS provider for VK Cloud
+- **[dnsprovider]** Add DNS provider for YandexCloud
+- **[dnsprovider]** digitalocean: configurable base URL
+- **[dnsprovider]** loopia: add configurable API endpoint
+- **[dnsprovider]** pdns: notify secondary servers after updates
+
+### Changed:
+
+- **[dnsprovider]** allinkl: removed deprecated sha1 hashing
+- **[dnsprovider]** auroradns: update authentification
+- **[dnsprovider]** dnspod: deprecated. Use Tencent Cloud instead.
+- **[dnsprovider]** exoscale: migrate to API v2 endpoints
+- **[dnsprovider]** gcloud: update golang.org/x/oauth2
+- **[dnsprovider]** lightsail: cleanup
+- **[dnsprovider]** sakuracloud: update api client library
+- **[cname]** take out CNAME support from experimental features
+- **[lib,cname]** add recursive CNAME lookup support
+- **[lib]** Remove embedded issuer certificates from issued certificate if bundle is false
+
+### Fixed:
+- **[dnsprovider]** luadns: fix cname support
+- **[dnsprovider]** njalla: fix record id unmarshal error
+- **[dnsprovider]** tencentcloud: fix subdomain error
+
+## [v4.8.0] - 2022-06-30
+
+### Added
+
+- **[dnsprovider]** Add DNS provider for Variomedia
+- **[dnsprovider]** Add NearlyFreeSpeech DNS Provider
+- **[cli]** Add a --user-agent flag to lego-cli
+
+### Changed
+
+- new logo
+- **[cli]** feat: sleep at renewal
+- **[cli]** cli/renew: skip random sleep if stdout is a terminal
+- **[dnsprovider]** hetzner: set min TTL to 60s
+- **[docs]** refactoring and cleanup
+
+## [v4.7.0] - 2022-05-27
+
+### Added:
+
+- **[dnsprovider]** Add DNS provider for iwantmyname
+- **[dnsprovider]** Add DNS Provider for IIJ DNS Platform Service
+- **[dnsprovider]** Add DNS provider for Vercel
+- **[dnsprovider]** route53: add assume role ARN
+- **[dnsprovider]** dnsimple: add debug option
+- **[cli]** feat: add `LEGO_CERT_PEM_PATH` and `LEGO_CERT_PFX_PATH`
+
+### Changed:
+
+- **[dnsprovider]** gcore: change dns api url
+- **[dnsprovider]** bluecat: rewrite provider implementation
+
+### Fixed:
+
+- **[dnsprovider]** rfc2136: fix TSIG secret
+- **[dnsprovider]** tencentcloud: fix InvalidParameter.DomainInvalid error when using DNS challenges
+- **[lib]** fix: panic in certcrypto.ParsePEMPrivateKey
+
+## [v4.6.0] - 2022-01-18
+
+### Added
+
+- **[dnsprovider]** Add DNS provider for UKFast SafeDNS
+- **[dnsprovider]** Add DNS Provider for Tencent Cloud
+- **[dnsprovider]** azure: add support for Azure Private Zone DNS
+- **[dnsprovider]** exec: add sequence interval
+- **[cli]** Add a `--pfx`, and `--pfx.pas`s option to generate a PKCS#12 (`.pfx`) file.
+- **[lib]** Extended support of cert pool (`LEGO_CA_CERTIFICATES` and `LEGO_CA_SYSTEM_CERT_POOL`)
+- **[lib,httpprovider]** added uds capability to http challenge server
+
+### Changed
+
+- **[lib]** Extend validity of TLS-ALPN-01 certificates to 365 days
+- **[lib,cli]** Allows defining the reason for the certificate revocation
+
+### Fixed
+
+- **[dnsprovider]** mythicbeasts: fix token expiration
+- **[dnsprovider]** rackspace: change zone ID to string
+
+## [v4.5.3] - 2021-09-06
+
+### Fixed:
+
+- **[lib,cli]** fix: missing preferred chain param for renew request
+
+## [v4.5.2] - 2021-09-01
+
+### Added:
+
+- **[dnsprovider]** Add DNS provider for all-inkl
+- **[dnsprovider]** Add DNS provider for Epik
+- **[dnsprovider]** Add DNS provider for freemyip.com
+- **[dnsprovider]** Add DNS provider for g-core labs
+- **[dnsprovider]** Add DNS provider for hosttech
+- **[dnsprovider]** Add DNS Provider for IBM Cloud (SoftLayer)
+- **[dnsprovider]** Add DNS provider for Internet.bs
+- **[dnsprovider]** Add DNS provider for nicmanager
+
+### Changed:
+
+- **[dnsprovider]** alidns: support ECS instance RAM role
+- **[dnsprovider]** alidns: support sts token credential
+- **[dnsprovider]** azure: zone name as environment variable
+- **[dnsprovider]** ovh: follow cname
+- **[lib,cli]** Add AlwaysDeactivateAuthorizations flag to ObtainRequest
+
+### Fixed:
+
+- **[dnsprovider]** infomaniak: fix subzone support
+- **[dnsprovider]** edgedns: fix Present and CleanUp logic
+- **[dnsprovider]** lightsail: wrong Region env var name
+- **[lib]** lib: fix backoff in SolverManager
+- **[lib]** lib: use permanent error instead of context cancellation
+- **[dnsprovider]** desec: bump to v0.6.0
+
+## [v4.5.1] - 2021-09-01
+
+Cancelled due to a CI issue, replaced by v4.5.2.
+
+## [v4.5.0] - 2021-09-30
+
+Cancelled due to a CI issue, replaced by v4.5.2.
+
+## [v4.4.0] - 2021-06-08
+
+### Added:
+
+- **[dnsprovider]** Add DNS provider for Infoblox
+- **[dnsprovider]** Add DNS provider for Porkbun
+- **[dnsprovider]** Add DNS provider for Simply.com
+- **[dnsprovider]** Add DNS provider for Sonic
+- **[dnsprovider]** Add DNS provider for VinylDNS
+- **[dnsprovider]** Add DNS provider for wedos
+
+### Changed:
+
+- **[cli]** log: Use stderr instead of stdout.
+- **[dnsprovider]** hostingde: autodetection of the zone name.
+- **[dnsprovider]** scaleway: use official SDK
+- **[dnsprovider]** powerdns: several improvements
+- **[lib]** lib: improve wait.For returns.
+
+### Fixed:
+
+- **[dnsprovider]** hurricane: add API rate limiter.
+- **[dnsprovider]** hurricane: only treat first word of response body as response code
+- **[dnsprovider]** exoscale: fix DNS provider debugging
+- **[dnsprovider]** wedos: fix api call parameters
+- **[dnsprovider]** nifcloud: Get zone info from dns01.FindZoneByFqdn
+- **[cli,lib]** csr: Support the type `NEW CERTIFICATE REQUEST`
+
+## [v4.3.1] - 2021-03-12
+
+### Fixed:
+
+- **[dnsprovider]** exoscale: fix dependency version.
+
+## [v4.3.0] - 2021-03-10
+
+### Added:
+
+- **[dnsprovider]** Add DNS provider for Njalla
+- **[dnsprovider]** Add DNS provider for Domeneshop
+- **[dnsprovider]** Add DNS provider for Hurricane Electric
+- **[dnsprovider]** designate: support for Openstack Application Credentials
+- **[dnsprovider]** edgedns: support for .edgerc file
+
+### Changed:
+
+- **[dnsprovider]** infomaniak: Make error message more meaningful
+- **[dnsprovider]** cloudns: Improve reliability
+- **[dnsprovider]** rfc2163: Removed support for MD5 algorithm. The default algorithm is now SHA1.
+
+### Fixed:
+
+- **[dnsprovider]** desec: fix error with default TTL
+- **[dnsprovider]** mythicbeasts: implement `ProviderTimeout`
+- **[dnsprovider]** dnspod: improve search accuracy when a domain have more than 100 records
+- **[lib]** Increase HTTP client timeouts
+- **[lib]** preferred chain only match root name
+
+## [v4.2.0] - 2021-01-24
+
+### Added:
+
+- **[dnsprovider]** Add DNS provider for Loopia
+- **[dnsprovider]** Add DNS provider for Ionos.
+
+### Changed:
+
+- **[dnsprovider]** acme-dns: update cpu/goacmedns to v0.1.1.
+- **[dnsprovider]** inwx: Increase propagation timeout to 360s to improve robustness
+- **[dnsprovider]** vultr: Update to govultr v2 API
+- **[dnsprovider]** pdns: get exact zone instead of all zones
+
+### Fixed:
+
+- **[dnsprovider]** vult, dnspod: fix default HTTP timeout.
+- **[dnsprovider]** pdns: URL request creation.
+- **[lib]** errors: Fix instance not being printed
+
+## [v4.1.3] - 2020-11-25
+
+### Fixed:
+
+- **[dnsprovider]** azure: fix error handling.
+
+## [v4.1.2] - 2020-11-21
+
+### Fixed:
+
+- **[lib]** fix: preferred chain support.
+
+## [v4.1.1] - 2020-11-19
+
+### Fixed:
+
+- **[dnsprovider]** otc: select correct zone if multiple returned
+- **[dnsprovider]** azure: fix target must be a non-nil pointer
+
+## [v4.1.0] - 2020-11-06
+
+### Added:
+
+- **[dnsprovider]** Add DNS provider for Infomaniak
+- **[dnsprovider]** joker: add support for SVC API
+- **[dnsprovider]** gcloud: add an option to allow the use of private zones
+
+### Changed:
+
+- **[dnsprovider]** rfc2136: ensure TSIG algorithm is fully qualified
+- **[dnsprovider]** designate: Deprecate OS_TENANT_NAME as required field
+
+### Fixed:
+
+- **[lib]** acme/api: use postAsGet instead of post for AccountService.Get
+- **[lib]** fix: use http.Header.Set method instead of Add.
+
+## [v4.0.1] - 2020-09-03
+
+### Fixed:
+
+- **[dnsprovider]** exoscale: change dependency version.
+
+## [v4.0.0] - 2020-09-02
+
+### Added:
+
+- **[cli], [lib]** Support "alternate" certificate links for selecting different signing Chains
+
+### Changed:
+
+- **[cli]** Replaces `ec384` by `ec256` as default key-type
+- **[lib]** Changes `ObtainForCSR` method signature
+
+### Removed:
+
+- **[dnsprovider]** Replaces FastDNS by EdgeDNS
+- **[dnsprovider]** Removes old Linode provider
+- **[lib]** Removes `AddPreCheck` function
+
+## [v3.9.0] - 2020-09-01
+
+### Added:
+
+- **[dnsprovider]** Add Akamai Edgedns. Deprecate FastDNS
+- **[dnsprovider]** Add DNS provider for HyperOne
+
+### Changed:
+
+- **[dnsprovider]** designate: add support for Openstack clouds.yaml
+- **[dnsprovider]** azure: allow selecting environments
+- **[dnsprovider]** desec: applies API rate limits.
+
+### Fixed:
+
+- **[dnsprovider]** namesilo: fix cleanup.
+
+## [v3.8.0] - 2020-07-02
+
+### Added:
+
+- **[cli]** cli: add hook on the run command.
+- **[dnsprovider]** inwx: Two-Factor-Authentication
+- **[dnsprovider]** Add DNS provider for ArvanCloud
+
+### Changed:
+
+- **[dnsprovider]** vultr: bumping govultr version
+- **[dnsprovider]** desec: improve error logs.
+- **[lib]** Ensures the return of a location during account updates
+- **[dnsprovider]** route53: Document all AWS credential environment variables
+
+### Fixed:
+
+- **[dnsprovider]** stackpath: fix subdomain support.
+- **[dnsprovider]** arvandcloud: fix record name.
+- **[dnsprovider]** fix: multi-va.
+- **[dnsprovider]** constellix: fix search records API call.
+- **[dnsprovider]** hetzner: fix record name.
+- **[lib]** Registrar.ResolveAccountByKey: Fix malformed request
+
+## [v3.7.0] - 2020-05-11
+
+### Added:
+
+- **[dnsprovider]** Add DNS provider for Netlify.
+- **[dnsprovider]** Add DNS provider for deSEC.io
+- **[dnsprovider]** Add DNS provider for LuaDNS
+- **[dnsprovider]** Adding Hetzner DNS provider
+- **[dnsprovider]** Add DNS provider for Mythic beasts DNSv2
+- **[dnsprovider]** Add DNS provider for Yandex.
+
+### Changed:
+
+- **[dnsprovider]** Upgrade DNSimple client to 0.60.0
+- **[dnsprovider]** update aws sdk
+
+### Fixed:
+
+- **[dnsprovider]** autodns: removes TXT records during CleanUp.
+- **[dnsprovider]** Fix exoscale HTTP timeout
+- **[cli]** fix: renew path information.
+- **[cli]** Fix account storage location warning message
+
+## [v3.6.0] - 2020-04-24
+
+### Added:
+
+- **[dnsprovider]** Add DNS provider for CloudDNS.
+- **[dnsprovider]** alicloud: add support for domain with punycode
+- **[dnsprovider]** cloudns: Add subuser support
+- **[cli]** Information about renewed certificates are now passed to the renew hook
+
+### Changed:
+
+- **[dnsprovider]** acmedns: Update cpu/goacmedns v0.0.1 -> v0.0.2
+- **[dnsprovider]** alicloud: update sdk dependency version to v1.61.112
+- **[dnsprovider]** azure: Allow for the use of MSI
+- **[dnsprovider]** constellix: improve challenge.
+- **[dnsprovider]** godaddy: allow parallel solve.
+- **[dnsprovider]** namedotcom: get the actual registered domain so we can remove just that from the hostname to be created
+- **[dnsprovider]** transip: updated the client to v6
+
+### Fixed:
+
+- **[dnsprovider]** ns1: fix missing domain in log 
+- **[dnsprovider]** rimuhosting: use HTTP client from config.
+
+## [v3.5.0] - 2020-03-15
+
+### Added:
+
+- **[dnsprovider]** Add DNS provider for Dynu.
+- **[dnsprovider]** Add DNS provider for reg.ru
+- **[dnsprovider]** Add DNS provider for Zonomi and RimuHosting.
+- **[cli]** Building binaries for arm 6 and 5
+- **[cli]** Uses CGO_ENABLED=0
+- **[cli]** Multi-arch Docker image.
+- **[cli]** Adds `--name` flag to list command.
+
+### Changed:
+
+- **[lib]** lib: Improve cleanup log messages.
+- **[lib]** Wrap errors.
+
+### Fixed:
+
+- **[dnsprovider]** azure: pass AZURE_CLIENT_SECRET_FILE to autorest.Authorizer
+- **[dnsprovider]** gcloud: fixes issues when used with GKE Workload Identity
+- **[dnsprovider]** oraclecloud: fix subdomain support
+
+## [v3.4.0] - 2020-02-25
+
+### Added:
+
+- **[dnsprovider]** Add DNS provider for Constellix
+- **[dnsprovider]** Add DNS provider for Servercow.
+- **[dnsprovider]** Add DNS provider for Scaleway
+- **[cli]** Add "LEGO_PATH" environment variable
+
+### Changed:
+
+- **[dnsprovider]** route53: allow custom client to be provided
+- **[dnsprovider]** namecheap: allow external domains
+- **[dnsprovider]** namecheap: add sandbox support.
+- **[dnsprovider]** ovh: Improve provider documentation
+- **[dnsprovider]** route53: Improve provider documentation
+
+### Fixed:
+
+- **[dnsprovider]** zoneee: fix subdomains.
+- **[dnsprovider]** designate: Don't clean up managed records like SOA and NS
+- **[dnsprovider]** dnspod: update lib.
+- **[lib]** crypto: Treat CommonName as optional
+- **[lib]** chore: update cenkalti/backoff to v4.
+
+## [v3.3.0] - 2020-01-08
+
+### Added:
+- **[dnsprovider]** Add DNS provider for Checkdomain
+- **[lib]** Add support to update account
+
+### Changed:
+- **[dnsprovider]** gcloud: Auto-detection of the project ID.
+- **[lib]** Successfully parse private key PEM blocks
+
+### Fixed:
+- **[dnsprovider]** Update dnspod, because of API breaking changes.
+
+## [v3.2.0] - 2019-11-10
+
+### Added:
+- **[dnsprovider]** Add support for autodns
+
+### Changed:
+- **[dnsprovider]** httpreq: Allow use environment vars from a `_FILE` file
+- **[lib]** Don't deactivate valid authorizations
+- **[lib]** Expose more SOA fields found by dns01.FindZoneByFqdn
+
+### Fixed:
+- **[dnsprovider]** use token as unique ID.
+
+## [v3.1.0] - 2019-10-07
+
+### Added:
+- **[dnsprovider]** Add DNS provider for Liquid Web
+- **[dnsprovider]** cloudflare: add support for API tokens
+- **[cli]** feat: ease operation behind proxy servers
+
+### Changed:
+- **[dnsprovider]** cloudflare: update client
+- **[dnsprovider]** linodev4: propagation timeout configuration.
+
+### Fixed:
+- **[dnsprovider]** ovh: fix int overflow.
+- **[dnsprovider]** bindman: fix client version.
+
+## [v3.0.2] - 2019-08-15
+
+### Fixed:
+- Invalid pseudo version (related to Cloudflare client).
+
+## [v3.0.1] - 2019-08-14
+
+There was a problem when creating the tag v3.0.1, this tag has been invalidate.
+
+## [v3.0.0] - 2019-08-05
+
+### Changed:
+- migrate to go module (new import github.com/go-acme/lego/v3/)
+- update DNS clients
+
+## [v2.7.2] - 2019-07-30
+
+### Fixed:
+- **[dnsprovider]** vultr: quote TXT record
+
+## [v2.7.1] - 2019-07-22
+
+### Fixed:
+- **[dnsprovider]** vultr: invalid record type.
+
+## [v2.7.0] - 2019-07-17
+
+### Added:
+- **[dnsprovider]** Add DNS provider for namesilo
+- **[dnsprovider]** Add DNS provider for versio.nl
+
+### Changed:
+- **[dnsprovider]** Update DNS providers libs.
+- **[dnsprovider]** joker: support username and password.
+- **[dnsprovider]** Vultr: Switch to official client
+
+### Fixed:
+- **[dnsprovider]** otc: Prevent sending empty body.
+
+## [v2.6.0] - 2019-05-27
+
+### Added:
+- **[dnsprovider]** Add support for Joker.com DMAPI
+- **[dnsprovider]** Add support for Bindman DNS provider
+- **[dnsprovider]** Add support for EasyDNS
+- **[lib]** Get an existing certificate by URL
+
+### Changed:
+- **[dnsprovider]** digitalocean: LEGO_EXPERIMENTAL_CNAME_SUPPORT support
+- **[dnsprovider]** gcloud: Use fqdn to get zone Present/CleanUp
+- **[dnsprovider]** exec: serial behavior
+- **[dnsprovider]** manual: serial behavior.
+- **[dnsprovider]** Strip newlines when reading environment variables from `_FILE` suffixed files.
+
+### Fixed:
+- **[cli]** fix: cli disable-cp option.
+- **[dnsprovider]** gcloud: fix zone visibility.
+
+## [v2.5.0] - 2019-04-17
+
+### Added:
+- **[cli]** Adds renew hook
+- **[dnsprovider]** Adds 'Since' to DNS providers documentation
+
+### Changed:
+- **[dnsprovider]** gcloud: use public DNS zones
+- **[dnsprovider]** route53: enhance documentation.
+
+### Fixed:
+- **[dnsprovider]** cloudns: fix TTL and status validation
+- **[dnsprovider]** sakuracloud: supports concurrent update
+- **[dnsprovider]** Disable authz when solve fail.
+- Add tzdata to the Docker image.
+
+## [v2.4.0] - 2019-03-25
+
+- Migrate from xenolf/lego to go-acme/lego.
+
+### Added:
+- **[dnsprovider]** Add DNS Provider for Domain Offensive (do.de)
+- **[dnsprovider]** Adds information about '_FILE' suffix.
+
+### Fixed:
+- **[cli,dnsprovider]** Add 'manual' provider to the output of dnshelp
+- **[dnsprovider]** hostingde: Use provided ZoneName instead of domain
+- **[dnsprovider]** pdns: fix wildcard with SANs
+
+## [v2.3.0] - 2019-03-11
+
+### Added:
+- **[dnsprovider]** Add DNS Provider for ClouDNS.net
+- **[dnsprovider]** Add DNS Provider for Oracle Cloud
+
+### Changed:
+- **[cli]** Adds log when no renewal.
+- **[dnsprovider,lib]** Add a mechanism to wrap a PreCheckFunc
+- **[dnsprovider]** oraclecloud: better way to get private key.
+- **[dnsprovider]** exoscale: update library
+
+### Fixed:
+- **[dnsprovider]** OVH: Refresh zone after deleting challenge record
+- **[dnsprovider]** oraclecloud: ttl config and timeout 
+- **[dnsprovider]** hostingde: fix client fails if customer has no access to dns-groups
+- **[dnsprovider]** vscale: getting sub-domain
+- **[dnsprovider]** selectel: getting sub-domain
+- **[dnsprovider]** vscale: fix TXT records clean up
+- **[dnsprovider]** selectel: fix TXT records clean up
+
+## [v2.2.0] - 2019-02-08
+
+### Added:
+- **[dnsprovider]** Add support for Openstack Designate as a DNS provider
+- **[dnsprovider]** gcloud: Option to specify gcloud service account json by env as string
+- **[experimental feature]** Resolve CNAME when creating dns-01 challenge. To enable: set `LEGO_EXPERIMENTAL_CNAME_SUPPORT` to `true`.
+ 
+### Changed:
+- **[cli]** Applies Let’s Encrypt’s recommendation about renew. The option `--days` of the command `renew` has a new default value (`30`)
+- **[lib]** Uses a jittered exponential backoff
+
+### Fixed:
+- **[cli]** CLI and key type.
+- **[dnsprovider]** httpreq: Endpoint with path.
+- **[dnsprovider]** fastdns: Do not overwrite existing TXT records
+- Log wildcard domain correctly in validation
+
+## [v2.1.0] - 2019-01-24
+
+### Added:
+- **[dnsprovider]** Add support for zone.ee as a DNS provider.
+
+### Changed:
+- **[dnsprovider]** nifcloud: Change DNS base url.
+- **[dnsprovider]** gcloud: More detailed information about Google Cloud DNS.
+
+### Fixed:
+- **[lib]** fix: OCSP, set HTTP client.
+- **[dnsprovider]** alicloud: fix pagination.
+- **[dnsprovider]** namecheap: fix panic.
+
+## [v2.0.0] - 2019-01-09
+
+### Added:
+- **[cli,lib]** Option to disable the complete propagation Requirement
+- **[lib,cli]** Support non-ascii domain name (punnycode)
+- **[cli,lib]** Add configurable timeout when obtaining certificates
+- **[cli]** Archive revoked certificates
+- **[cli]** Add command to list certificates.
+- **[cli]** support for renew with CSR
+- **[cli]** add SAN on renew
+- **[lib]** Adds `Remove` for challenges
+- **[lib]** Add version to xenolf-acme in User-Agent.
+- **[dnsprovider]** The ability for a DNS provider to solve the challenge sequentially
+- **[dnsprovider]** Add DNS provider for "HTTP request".
+- **[dnsprovider]** Add DNS Provider for Vscale
+- **[dnsprovider]** Add DNS Provider for TransIP
+- **[dnsprovider]** Add DNS Provider for inwx
+- **[dnsprovider]** alidns: add support to handle more than 20 domains
+
+### Changed:
+- **[lib]** Check all challenges in a predictable order
+- **[lib]** Poll authz URL instead of challenge URL
+- **[lib]** Check all nameservers in a predictable order
+- **[lib]** Logs every iteration of waiting for the propagation
+- **[cli]** `--http`: enable HTTP challenge **important**
+- **[cli]** `--http.port`: previously named `--http`
+- **[cli]** `--http.webroot`: previously named `--webroot`
+- **[cli]** `--http.memcached-host`: previously named `--memcached-host`
+- **[cli]** `--tls`: enable TLS challenge **important**
+- **[cli]** `--tls.port`:  previously named `--tls`
+- **[cli]** `--dns.resolvers`: previously named `--dns-resolvers`
+- **[cli]** the option `--days` of the command `renew` has default value (`15`)
+- **[dnsprovider]** gcloud: Use GCE_PROJECT for project always, if specified
+
+### Removed:
+- **[lib]** Remove `SetHTTP01Address`
+- **[lib]** Remove `SetTLSALPN01Address`
+- **[lib]** Remove `Exclude`
+- **[cli]** Remove `--exclude`, `-x` 
+
+### Fixed:
+- **[lib]** Fixes revocation for subdomains and non-ascii domains
+- **[lib]** Disable pending authorizations
+- **[dnsprovider]** transip: concurrent access to the API.
+- **[dnsprovider]** gcloud: fix for wildcard
+- **[dnsprovider]** Azure: Do not overwrite existing TXT records
+- **[dnsprovider]** fix: Cloudflare error.
+
+## [v1.2.0] - 2018-11-04
+
+### Added:
+- **[dnsprovider]** Add DNS Provider for ConoHa DNS
+- **[dnsprovider]** Add DNS Provider for MyDNS.jp
+- **[dnsprovider]** Add DNS Provider for Selectel
+
+### Fixed:
+- **[dnsprovider]** netcup: make unmarshalling of api-responses more lenient.
+
+### Changed:
+- **[dnsprovider]** aurora: change DNS client
+- **[dnsprovider]** azure: update auth to support instance metadata service
+- **[dnsprovider]** dnsmadeeasy: log response body on error
+- **[lib]** TLS-ALPN-01: Update idPeAcmeIdentifierV1, draft refs.
+- **[lib]** Do not send a JWS body when POSTing challenges.
+- **[lib]** Support POST-as-GET.
+
+## [v1.1.0] - 2018-10-16
+
+### Added:
+- **[lib]** TLS-ALPN-01 Challenge
+- **[cli]** Add filename parameter
+- **[dnsprovider]** Allow to configure TTL, interval and timeout
+- **[dnsprovider]** Add support for reading DNS provider setup from files
+- **[dnsprovider]** Add DNS Provider for ACME-DNS
+- **[dnsprovider]** Add DNS Provider for ALIYUN DNS
+- **[dnsprovider]** Add DNS Provider for DreamHost
+- **[dnsprovider]** Add DNS provider for hosting.de
+- **[dnsprovider]** Add DNS Provider for IIJ
+- **[dnsprovider]** Add DNS Provider for netcup
+- **[dnsprovider]** Add DNS Provider for NIFCLOUD DNS
+- **[dnsprovider]** Add DNS Provider for SAKURA Cloud
+- **[dnsprovider]** Add DNS Provider for Stackpath
+- **[dnsprovider]** Add DNS Provider for VegaDNS
+- **[dnsprovider]** exec: add EXEC_MODE=RAW support.
+- **[dnsprovider]** cloudflare: support for CF_API_KEY and CF_API_EMAIL
+
+### Fixed:
+- **[lib]** Don't trust identifiers order.
+- **[lib]** Fix missing issuer certificates from Let's Encrypt
+- **[dnsprovider]** duckdns: fix TXT record update url
+- **[dnsprovider]** duckdns: fix subsubdomain
+- **[dnsprovider]** gcloud: update findTxtRecords to use Name=fqdn and Type=TXT
+- **[dnsprovider]** lightsail: Fix Domain does not exist error
+- **[dnsprovider]** ns1: use the authoritative zone and not the domain name
+- **[dnsprovider]** ovh: check error to avoid panic due to nil client
+
+### Changed:
+- **[lib]** Submit all dns records up front, then validate serially
+
+## [v1.0.0] - 2018-05-30
+
+### Changed:
+- **[lib]** ACME v2 Support.
+- **[dnsprovider]** Renamed `/providers/dns/googlecloud` to `/providers/dns/gcloud`.
+- **[dnsprovider]** Modified Google Cloud provider `gcloud.NewDNSProviderServiceAccount` function to extract the project id directly from the service account file.
+- **[dnsprovider]** Made errors more verbose for the Cloudflare provider.
+
+## [v0.5.0] - 2018-05-29
+
+### Added:
+- **[dnsprovider]** Add DNS challenge provider `exec`
+- **[dnsprovider]** Add DNS Provider for Akamai FastDNS
+- **[dnsprovider]** Add DNS Provider for Bluecat DNS
+- **[dnsprovider]** Add DNS Provider for CloudXNS
+- **[dnsprovider]** Add DNS Provider for Duck DNS
+- **[dnsprovider]** Add DNS Provider for Gandi Beta Platform (LiveDNS)
+- **[dnsprovider]** Add DNS Provider for GleSYS API
+- **[dnsprovider]** Add DNS Provider for GoDaddy
+- **[dnsprovider]** Add DNS Provider for Lightsail
+- **[dnsprovider]** Add DNS Provider for Name.com
+
+### Fixed:
+- **[dnsprovider]** Azure: Added missing environment variable in the comments
+- **[dnsprovider]** PowerDNS: Fix zone URL, add leading slash.
+- **[dnsprovider]** DNSimple: Fix api
+- **[cli]** Correct help text for `--dns-resolvers` default.
+- **[cli]** renew/revoke - don't panic on wrong account.
+- **[lib]** Fix zone detection for cross-zone cnames.
+- **[lib]** Use proxies from environment when making outbound http connections.
+
+### Changed:
+- **[lib]** Users of an effective top-level domain can use the DNS challenge.
+- **[dnsprovider]** Azure: Refactor to work with new Azure SDK version.
+- **[dnsprovider]** Cloudflare and Azure: Adding output of which envvars are missing.
+- **[dnsprovider]** Dyn DNS: Slightly improve provider error reporting.
+- **[dnsprovider]** Exoscale: update to latest egoscale version.
+- **[dnsprovider]** Route53: Use NewSessionWithOptions instead of deprecated New.
+
+## [0.4.1] - 2017-09-26
+
+### Added:
+- lib: A new DNS provider for OTC.
+- lib: The `AWS_HOSTED_ZONE_ID` environment variable for the Route53 DNS provider to directly specify the zone.
+- lib: The `RFC2136_TIMEOUT` enviroment variable to make the timeout for the RFC2136 provider configurable.
+- lib: The `GCE_SERVICE_ACCOUNT_FILE` environment variable to specify a service account file for the Google Cloud DNS provider.
+
+### Fixed:
+- lib: Fixed an authentication issue with the latest Azure SDK.
+
+## [0.4.0] - 2017-07-13
+
+### Added:
+- CLI: The `--http-timeout` switch. This allows for an override of the default client HTTP timeout.
+- lib: The `HTTPClient` field. This allows for an override of the default HTTP timeout for library HTTP requests.
+- CLI: The `--dns-timeout` switch. This allows for an override of the default DNS timeout for library DNS requests.
+- lib: The `DNSTimeout` switch. This allows for an override of the default client DNS timeout.
+- lib: The `QueryRegistration` function on `acme.Client`. This performs a POST on the client registration's URI and gets the updated registration info.
+- lib: The `DeleteRegistration` function on `acme.Client`. This deletes the registration as currently configured in the client.
+- lib: The `ObtainCertificateForCSR` function on `acme.Client`. The function allows to request a certificate for an already existing CSR.
+- CLI: The `--csr` switch. Allows to use already existing CSRs for certificate requests on the command line.
+- CLI: The `--pem` flag. This will change the certificate output so it outputs a .pem file concatanating the .key and .crt files together.
+- CLI: The `--dns-resolvers` flag. Allows for users to override the default DNS servers used for recursive lookup.
+- lib: Added a memcached provider for the HTTP challenge.
+- CLI: The `--memcached-host` flag. This allows to use memcached for challenge storage.
+- CLI: The `--must-staple` flag. This enables OCSP must staple in the generated CSR.
+- lib: The library will now honor entries in your resolv.conf.
+- lib: Added a field `IssuerCertificate` to the `CertificateResource` struct.
+- lib: A new DNS provider for OVH.
+- lib: A new DNS provider for DNSMadeEasy.
+- lib: A new DNS provider for Linode.
+- lib: A new DNS provider for AuroraDNS.
+- lib: A new DNS provider for NS1.
+- lib: A new DNS provider for Azure DNS.
+- lib: A new DNS provider for Rackspace DNS.
+- lib: A new DNS provider for Exoscale DNS.
+- lib: A new DNS provider for DNSPod.
+
+### Changed:
+- lib: Exported the `PreCheckDNS` field so library users can manage the DNS check in tests.
+- lib: The library will now skip challenge solving if a valid Authz already exists.
+
+### Removed:
+- lib: The library will no longer check for auto renewed certificates. This has been removed from the spec and is not supported in Boulder.
+
+### Fixed:
+- lib: Fix a problem with the Route53 provider where it was possible the verification was published to a private zone.
+- lib: Loading an account from file should fail if a integral part is nil
+- lib: Fix a potential issue where the Dyn provider could resolve to an incorrect zone.
+- lib: If a registration encounteres a conflict, the old registration is now recovered.
+- CLI: The account.json file no longer has the executable flag set.
+- lib: Made the client registration more robust in case of a 403 HTTP response.
+- lib: Fixed an issue with zone lookups when they have a CNAME in another zone.
+- lib: Fixed the lookup for the authoritative zone for Google Cloud.
+- lib: Fixed a race condition in the nonce store.
+- lib: The Google Cloud provider now removes old entries before trying to add new ones.
+- lib: Fixed a condition where we could stall due to an early error condition.
+- lib: Fixed an issue where Authz object could end up in an active state after an error condition.
+
+## [0.3.1] - 2016-04-19
+
+### Added:
+- lib: A new DNS provider for Vultr.
+
+### Fixed:
+- lib: DNS Provider for DigitalOcean could not handle subdomains properly.
+- lib: handleHTTPError should only try to JSON decode error messages with the right content type.
+- lib: The propagation checker for the DNS challenge would not retry on send errors.
+
+
+## [0.3.0] - 2016-03-19
+
+### Added:
+- CLI: The `--dns` switch. To include the DNS challenge for consideration. When using this switch, all other solvers are disabled. Supported are the following solvers: cloudflare, digitalocean, dnsimple, dyn, gandi, googlecloud, namecheap, route53, rfc2136 and manual.
+- CLI: The `--accept-tos`  switch. Indicates your acceptance of the Let's Encrypt terms of service without prompting you.
+- CLI: The `--webroot` switch. The HTTP-01 challenge may now be completed by dropping a file into a webroot. When using this switch, all other solvers are disabled.
+- CLI: The `--key-type` switch. This replaces the `--rsa-key-size` switch and supports the following key types: EC256, EC384, RSA2048, RSA4096 and RSA8192.
+- CLI: The `--dnshelp` switch. This displays a more in-depth help topic for DNS solvers.
+- CLI: The `--no-bundle` sub switch for the `run` and `renew` commands. When this switch is set, the CLI will not bundle the issuer certificate with your certificate.
+- lib: A new type for challenge identifiers `Challenge`
+- lib: A new interface for custom challenge providers `acme.ChallengeProvider`
+- lib: A new interface for DNS-01 providers to allow for custom timeouts for the validation function `acme.ChallengeProviderTimeout`
+- lib: SetChallengeProvider function. Pass a challenge identifier and a Provider to replace the default behaviour of a challenge.
+- lib: The DNS-01 challenge has been implemented with modular solvers using the `ChallengeProvider` interface. Included solvers are: cloudflare, digitalocean, dnsimple, gandi, namecheap, route53, rfc2136 and manual.
+- lib: The `acme.KeyType` type was added and is used for the configuration of crypto parameters for RSA and EC keys. Valid KeyTypes are: EC256, EC384, RSA2048, RSA4096 and RSA8192.
+
+### Changed
+- lib: ExcludeChallenges now expects to be passed an array of `Challenge` types.
+- lib: HTTP-01 now supports custom solvers using the `ChallengeProvider` interface.
+- lib: TLS-SNI-01 now supports custom solvers using the `ChallengeProvider` interface.
+- lib: The `GetPrivateKey` function in the `acme.User` interface is now expected to return a `crypto.PrivateKey` instead of an `rsa.PrivateKey` for EC compat.
+- lib: The `acme.NewClient` function now expects an `acme.KeyType` instead of the keyBits parameter.
+ 
+### Removed
+- CLI: The `rsa-key-size` switch was removed in favor of `key-type` to support EC keys.
+
+### Fixed
+- lib: Fixed a race condition in HTTP-01
+- lib: Fixed an issue where status codes on ACME challenge responses could lead to no action being taken.
+- lib: Fixed a regression when calling the Renew function with a SAN certificate.
+
+## [0.2.0] - 2016-01-09
+
+### Added:
+- CLI: The `--exclude` or `-x` switch. To exclude a challenge from being solved.
+- CLI: The `--http` switch. To set the listen address and port of HTTP based challenges. Supports `host:port` and `:port` for any interface.
+- CLI: The `--tls` switch. To set the listen address and port of TLS based challenges. Supports `host:port` and `:port` for any interface.
+- CLI: The `--reuse-key` switch for the `renew` operation. This lets you reuse an existing private key for renewals.
+- lib: ExcludeChallenges function. Pass an array of challenge identifiers to exclude them from solving.
+- lib: SetHTTPAddress function. Pass a port to set the listen port for HTTP based challenges.
+- lib: SetTLSAddress function. Pass a port to set the listen port of TLS based challenges.
+- lib: acme.UserAgent variable. Use this to customize the user agent on all requests sent by lego.
+
+### Changed:
+- lib: NewClient does no longer accept the optPort parameter
+- lib: ObtainCertificate now returns a SAN certificate if you pass more then one domain.
+- lib: GetOCSPForCert now returns the parsed OCSP response instead of just the status.
+- lib: ObtainCertificate has a new parameter `privKey crypto.PrivateKey` which lets you reuse an existing private key for new certificates.
+- lib: RenewCertificate now expects the PrivateKey property of the CertificateResource to be set only if you want to reuse the key.
+
+### Removed:
+- CLI: The `--port` switch was removed.
+- lib: RenewCertificate does no longer offer to also revoke your old certificate.
+
+### Fixed:
+- CLI: Fix logic using the `--days` parameter for renew
+
+## [0.1.1] - 2015-12-18
+
+### Added:
+- CLI: Added a way to automate renewal through a cronjob using the --days parameter to renew
+
+### Changed:
+- lib: Improved log output on challenge failures.
+
+### Fixed:
+- CLI: The short parameter for domains would not get accepted
+- CLI: The cli did not return proper exit codes on error library errors.
+- lib: RenewCertificate did not properly renew SAN certificates.
+
+### Security
+- lib: Fix possible DOS on GetOCSPForCert
+
+## [0.1.0] - 2015-12-03
+- Initial release
+
+[0.3.1]: https://github.com/go-acme/lego/compare/v0.3.0...v0.3.1
+[0.3.0]: https://github.com/go-acme/lego/compare/v0.2.0...v0.3.0
+[0.2.0]: https://github.com/go-acme/lego/compare/v0.1.1...v0.2.0
+[0.1.1]: https://github.com/go-acme/lego/compare/v0.1.0...v0.1.1
+[0.1.0]: https://github.com/go-acme/lego/tree/v0.1.0

CONTRIBUTING.md

@@ -0,0 +1,80 @@
+# How to contribute to lego
+
+Contributions in the form of patches and proposals are essential to keep lego great and to make it even better.
+To ensure a great and easy experience for everyone, please review the few guidelines in this document.
+
+## Bug reports
+
+- Use the issue search to see if the issue has already been reported.
+- Also look for closed issues to see if your issue has already been fixed.
+- If both of the above do not apply create a new issue and include as much information as possible.
+
+Bug reports should include all information a person could need to reproduce your problem without the need to
+follow up for more information. If possible, provide detailed steps for us to reproduce it, the expected behaviour and the actual behaviour.
+
+## Feature proposals and requests
+
+Feature requests are welcome and should be discussed in an issue.
+Please keep proposals focused on one thing at a time and be as detailed as possible.
+It is up to you to make a strong point about your proposal and convince us of the merits and the added complexity of this feature.
+
+## Pull requests
+
+Patches, new features and improvements are a great way to help the project.
+Please keep them focused on one thing and do not include unrelated commits.
+
+All pull requests which alter the behaviour of the program, add new behaviour or somehow alter code in a non-trivial way should **always** include tests.
+
+If you want to contribute a significant pull request (with a non-trivial workload for you) please **ask first**. We do not want you to spend
+a lot of time on something the project's developers might not want to merge into the project.
+
+**IMPORTANT**: By submitting a patch, you agree to allow the project
+owners to license your work under the terms of the [MIT License](LICENSE).
+
+### How to create a pull request
+
+Requirements:
+
+- `go` v1.15+
+- environment variable: `GO111MODULE=on`
+
+First, you have to install [GoLang](https://golang.org/doc/install) and [golangci-lint](https://github.com/golangci/golangci-lint#install).
+
+```bash
+# Create the root folder
+mkdir -p $GOPATH/src/github.com/go-acme
+cd $GOPATH/src/github.com/go-acme
+
+# clone your fork
+git clone git@github.com:YOUR_USERNAME/lego.git
+cd lego
+
+# Add the go-acme/lego remote
+git remote add upstream git@github.com:go-acme/lego.git
+git fetch upstream
+```
+
+```bash
+# Create your branch
+git checkout -b my-feature
+
+## Create your code ##
+```
+
+```bash
+# Format
+make fmt
+# Linters
+make checks
+# Tests
+make test
+# Compile
+make build
+```
+
+```bash
+# push your branch
+git push -u origin my-feature
+
+## create a pull request on GitHub ##
+```

Dockerfile

@@ -0,0 +1,24 @@
+FROM golang:1-alpine as builder
+
+RUN apk --no-cache --no-progress add make git
+
+WORKDIR /go/lego
+
+ENV GO111MODULE on
+
+# Download go modules
+COPY go.mod .
+COPY go.sum .
+RUN go mod download
+
+COPY . .
+RUN make build
+
+FROM alpine:3
+RUN apk update \
+    && apk add --no-cache ca-certificates tzdata \
+    && update-ca-certificates
+
+COPY --from=builder /go/lego/dist/lego /usr/bin/lego
+
+ENTRYPOINT [ "/usr/bin/lego" ]

LICENSE

@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2015-2017 Sebastian Erhart
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

Makefile

@@ -0,0 +1,80 @@
+.PHONY: clean checks test build image e2e fmt
+
+export GO111MODULE=on
+export CGO_ENABLED=0
+
+LEGO_IMAGE := goacme/lego
+MAIN_DIRECTORY := ./cmd/lego/
+
+BIN_OUTPUT := $(if $(filter $(shell go env GOOS), windows), dist/lego.exe, dist/lego)
+
+TAG_NAME := $(shell git tag -l --contains HEAD)
+SHA := $(shell git rev-parse HEAD)
+VERSION := $(if $(TAG_NAME),$(TAG_NAME),$(SHA))
+
+default: clean generate-dns checks test build
+
+clean:
+	@echo BIN_OUTPUT: ${BIN_OUTPUT}
+	rm -rf dist/ builds/ cover.out
+
+build: clean
+	@echo Version: $(VERSION)
+	go build -trimpath -ldflags '-X "main.version=${VERSION}"' -o ${BIN_OUTPUT} ${MAIN_DIRECTORY}
+
+image:
+	@echo Version: $(VERSION)
+	docker build -t $(LEGO_IMAGE) .
+
+test: clean
+	go test -v -cover ./...
+
+e2e: clean
+	LEGO_E2E_TESTS=local go test -count=1 -v ./e2e/...
+
+checks:
+	golangci-lint run
+
+# Release helper
+.PHONY: patch minor major detach
+
+patch:
+	go run internal/release.go release -m patch
+
+minor:
+	go run internal/release.go release -m minor
+
+major:
+	go run internal/release.go release -m major
+
+detach:
+	go run internal/release.go detach
+
+# Docs
+.PHONY: docs-build docs-serve docs-themes
+
+docs-build: generate-dns
+	@make -C ./docs hugo-build
+
+docs-serve: generate-dns
+	@make -C ./docs hugo
+
+docs-themes:
+	@make -C ./docs hugo-themes
+
+# DNS Documentation
+.PHONY: generate-dns validate-doc
+
+generate-dns:
+	go generate ./...
+
+validate-doc: generate-dns
+validate-doc: DOC_DIRECTORIES := ./docs/ ./cmd/
+validate-doc:
+	@if git diff --exit-code --quiet $(DOC_DIRECTORIES) 2>/dev/null; then \
+		echo 'All documentation changes are done the right way.'; \
+	else \
+		echo 'The documentation must be regenerated, please use `make generate-dns`.'; \
+		git status --porcelain -- $(DOC_DIRECTORIES) 2>/dev/null; \
+		exit 2; \
+	fi

README.md

@@ -1,3 +1,90 @@
-# WIP area: this repo is just a fork!
+<div align="center">
+  <img alt="lego logo" src="./docs/static/images/lego-logo.min.svg">
+  <p>Automatic Certificates and HTTPS for everyone.</p>
+</div>
 
-Useful things may be published only in [other branches](../../../branches)
+# Lego
+
+Let's Encrypt client and ACME library written in Go.
+
+[![Go Reference](https://pkg.go.dev/badge/github.com/go-acme/lego/v4.svg)](https://pkg.go.dev/github.com/go-acme/lego/v4)
+[![Build Status](https://github.com//go-acme/lego/workflows/Main/badge.svg?branch=master)](https://github.com//go-acme/lego/actions)
+[![Docker Pulls](https://img.shields.io/docker/pulls/goacme/lego.svg)](https://hub.docker.com/r/goacme/lego/)
+
+## Features
+
+- ACME v2 [RFC 8555](https://www.rfc-editor.org/rfc/rfc8555.html)
+  - Support [RFC 8737](https://www.rfc-editor.org/rfc/rfc8737.html): TLS Application‑Layer Protocol Negotiation (ALPN) Challenge Extension
+  - Support [RFC 8738](https://www.rfc-editor.org/rfc/rfc8738.html): certificates for IP addresses
+  - Support [draft-ietf-acme-ari-01](https://datatracker.ietf.org/doc/draft-ietf-acme-ari/): Renewal Information (ARI) Extension
+- Register with CA
+- Obtain certificates, both from scratch or with an existing CSR
+- Renew certificates
+- Revoke certificates
+- Robust implementation of all ACME challenges
+  - HTTP (http-01)
+  - DNS (dns-01)
+  - TLS (tls-alpn-01)
+- SAN certificate support
+- [CNAME support](https://letsencrypt.org/2019/10/09/onboarding-your-customers-with-lets-encrypt-and-acme.html) by default
+- Comes with multiple optional [DNS providers](https://go-acme.github.io/lego/dns)
+- [Custom challenge solvers](https://go-acme.github.io/lego/usage/library/writing-a-challenge-solver/)
+- Certificate bundling
+- OCSP helper function
+
+## Installation
+
+How to [install](https://go-acme.github.io/lego/installation/).
+
+## Usage
+
+- as a [CLI](https://go-acme.github.io/lego/usage/cli)
+- as a [library](https://go-acme.github.io/lego/usage/library)
+
+## Documentation
+
+Documentation is hosted live at https://go-acme.github.io/lego/.
+
+## DNS providers
+
+Detailed documentation is available [here](https://go-acme.github.io/lego/dns).
+
+<!-- START DNS PROVIDERS LIST -->
+
+|                                                                                 |                                                                                 |                                                                                 |                                                                                 |
+|---------------------------------------------------------------------------------|---------------------------------------------------------------------------------|---------------------------------------------------------------------------------|---------------------------------------------------------------------------------|
+| [Akamai EdgeDNS](https://go-acme.github.io/lego/dns/edgedns/)                   | [Alibaba Cloud DNS](https://go-acme.github.io/lego/dns/alidns/)                 | [all-inkl](https://go-acme.github.io/lego/dns/allinkl/)                         | [Amazon Lightsail](https://go-acme.github.io/lego/dns/lightsail/)               |
+| [Amazon Route 53](https://go-acme.github.io/lego/dns/route53/)                  | [ArvanCloud](https://go-acme.github.io/lego/dns/arvancloud/)                    | [Aurora DNS](https://go-acme.github.io/lego/dns/auroradns/)                     | [Autodns](https://go-acme.github.io/lego/dns/autodns/)                          |
+| [Azure (deprecated)](https://go-acme.github.io/lego/dns/azure/)                 | [AzureDNS](https://go-acme.github.io/lego/dns/azuredns/)                        | [Bindman](https://go-acme.github.io/lego/dns/bindman/)                          | [Bluecat](https://go-acme.github.io/lego/dns/bluecat/)                          |
+| [Brandit](https://go-acme.github.io/lego/dns/brandit/)                          | [Bunny](https://go-acme.github.io/lego/dns/bunny/)                              | [Checkdomain](https://go-acme.github.io/lego/dns/checkdomain/)                  | [Civo](https://go-acme.github.io/lego/dns/civo/)                                |
+| [CloudDNS](https://go-acme.github.io/lego/dns/clouddns/)                        | [Cloudflare](https://go-acme.github.io/lego/dns/cloudflare/)                    | [ClouDNS](https://go-acme.github.io/lego/dns/cloudns/)                          | [CloudXNS](https://go-acme.github.io/lego/dns/cloudxns/)                        |
+| [ConoHa](https://go-acme.github.io/lego/dns/conoha/)                            | [Constellix](https://go-acme.github.io/lego/dns/constellix/)                    | [Derak Cloud](https://go-acme.github.io/lego/dns/derak/)                        | [deSEC.io](https://go-acme.github.io/lego/dns/desec/)                           |
+| [Designate DNSaaS for Openstack](https://go-acme.github.io/lego/dns/designate/) | [Digital Ocean](https://go-acme.github.io/lego/dns/digitalocean/)               | [DNS Made Easy](https://go-acme.github.io/lego/dns/dnsmadeeasy/)                | [dnsHome.de](https://go-acme.github.io/lego/dns/dnshomede/)                     |
+| [DNSimple](https://go-acme.github.io/lego/dns/dnsimple/)                        | [DNSPod (deprecated)](https://go-acme.github.io/lego/dns/dnspod/)               | [Domain Offensive (do.de)](https://go-acme.github.io/lego/dns/dode/)            | [Domeneshop](https://go-acme.github.io/lego/dns/domeneshop/)                    |
+| [DreamHost](https://go-acme.github.io/lego/dns/dreamhost/)                      | [Duck DNS](https://go-acme.github.io/lego/dns/duckdns/)                         | [Dyn](https://go-acme.github.io/lego/dns/dyn/)                                  | [Dynu](https://go-acme.github.io/lego/dns/dynu/)                                |
+| [EasyDNS](https://go-acme.github.io/lego/dns/easydns/)                          | [Efficient IP](https://go-acme.github.io/lego/dns/efficientip/)                 | [Epik](https://go-acme.github.io/lego/dns/epik/)                                | [Exoscale](https://go-acme.github.io/lego/dns/exoscale/)                        |
+| [External program](https://go-acme.github.io/lego/dns/exec/)                    | [freemyip.com](https://go-acme.github.io/lego/dns/freemyip/)                    | [G-Core](https://go-acme.github.io/lego/dns/gcore/)                             | [Gandi Live DNS (v5)](https://go-acme.github.io/lego/dns/gandiv5/)              |
+| [Gandi](https://go-acme.github.io/lego/dns/gandi/)                              | [Glesys](https://go-acme.github.io/lego/dns/glesys/)                            | [Go Daddy](https://go-acme.github.io/lego/dns/godaddy/)                         | [Google Cloud](https://go-acme.github.io/lego/dns/gcloud/)                      |
+| [Google Domains](https://go-acme.github.io/lego/dns/googledomains/)             | [Hetzner](https://go-acme.github.io/lego/dns/hetzner/)                          | [Hosting.de](https://go-acme.github.io/lego/dns/hostingde/)                     | [Hosttech](https://go-acme.github.io/lego/dns/hosttech/)                        |
+| [HTTP request](https://go-acme.github.io/lego/dns/httpreq/)                     | [Hurricane Electric DNS](https://go-acme.github.io/lego/dns/hurricane/)         | [HyperOne](https://go-acme.github.io/lego/dns/hyperone/)                        | [IBM Cloud (SoftLayer)](https://go-acme.github.io/lego/dns/ibmcloud/)           |
+| [IIJ DNS Platform Service](https://go-acme.github.io/lego/dns/iijdpf/)          | [Infoblox](https://go-acme.github.io/lego/dns/infoblox/)                        | [Infomaniak](https://go-acme.github.io/lego/dns/infomaniak/)                    | [Internet Initiative Japan](https://go-acme.github.io/lego/dns/iij/)            |
+| [Internet.bs](https://go-acme.github.io/lego/dns/internetbs/)                   | [INWX](https://go-acme.github.io/lego/dns/inwx/)                                | [Ionos](https://go-acme.github.io/lego/dns/ionos/)                              | [IPv64](https://go-acme.github.io/lego/dns/ipv64/)                              |
+| [iwantmyname](https://go-acme.github.io/lego/dns/iwantmyname/)                  | [Joker](https://go-acme.github.io/lego/dns/joker/)                              | [Joohoi's ACME-DNS](https://go-acme.github.io/lego/dns/acme-dns/)               | [Liara](https://go-acme.github.io/lego/dns/liara/)                              |
+| [Linode (v4)](https://go-acme.github.io/lego/dns/linode/)                       | [Liquid Web](https://go-acme.github.io/lego/dns/liquidweb/)                     | [Loopia](https://go-acme.github.io/lego/dns/loopia/)                            | [LuaDNS](https://go-acme.github.io/lego/dns/luadns/)                            |
+| [Manual](https://go-acme.github.io/lego/dns/manual/)                            | [Metaname](https://go-acme.github.io/lego/dns/metaname/)                        | [MyDNS.jp](https://go-acme.github.io/lego/dns/mydnsjp/)                         | [MythicBeasts](https://go-acme.github.io/lego/dns/mythicbeasts/)                |
+| [Name.com](https://go-acme.github.io/lego/dns/namedotcom/)                      | [Namecheap](https://go-acme.github.io/lego/dns/namecheap/)                      | [Namesilo](https://go-acme.github.io/lego/dns/namesilo/)                        | [NearlyFreeSpeech.NET](https://go-acme.github.io/lego/dns/nearlyfreespeech/)    |
+| [Netcup](https://go-acme.github.io/lego/dns/netcup/)                            | [Netlify](https://go-acme.github.io/lego/dns/netlify/)                          | [Nicmanager](https://go-acme.github.io/lego/dns/nicmanager/)                    | [NIFCloud](https://go-acme.github.io/lego/dns/nifcloud/)                        |
+| [Njalla](https://go-acme.github.io/lego/dns/njalla/)                            | [Nodion](https://go-acme.github.io/lego/dns/nodion/)                            | [NS1](https://go-acme.github.io/lego/dns/ns1/)                                  | [Open Telekom Cloud](https://go-acme.github.io/lego/dns/otc/)                   |
+| [Oracle Cloud](https://go-acme.github.io/lego/dns/oraclecloud/)                 | [OVH](https://go-acme.github.io/lego/dns/ovh/)                                  | [plesk.com](https://go-acme.github.io/lego/dns/plesk/)                          | [Porkbun](https://go-acme.github.io/lego/dns/porkbun/)                          |
+| [PowerDNS](https://go-acme.github.io/lego/dns/pdns/)                            | [Rackspace](https://go-acme.github.io/lego/dns/rackspace/)                      | [RcodeZero](https://go-acme.github.io/lego/dns/rcodezero/)                      | [reg.ru](https://go-acme.github.io/lego/dns/regru/)                             |
+| [RFC2136](https://go-acme.github.io/lego/dns/rfc2136/)                          | [RimuHosting](https://go-acme.github.io/lego/dns/rimuhosting/)                  | [Sakura Cloud](https://go-acme.github.io/lego/dns/sakuracloud/)                 | [Scaleway](https://go-acme.github.io/lego/dns/scaleway/)                        |
+| [Selectel](https://go-acme.github.io/lego/dns/selectel/)                        | [Servercow](https://go-acme.github.io/lego/dns/servercow/)                      | [Simply.com](https://go-acme.github.io/lego/dns/simply/)                        | [Sonic](https://go-acme.github.io/lego/dns/sonic/)                              |
+| [Stackpath](https://go-acme.github.io/lego/dns/stackpath/)                      | [Tencent Cloud DNS](https://go-acme.github.io/lego/dns/tencentcloud/)           | [TransIP](https://go-acme.github.io/lego/dns/transip/)                          | [UKFast SafeDNS](https://go-acme.github.io/lego/dns/safedns/)                   |
+| [Ultradns](https://go-acme.github.io/lego/dns/ultradns/)                        | [Variomedia](https://go-acme.github.io/lego/dns/variomedia/)                    | [VegaDNS](https://go-acme.github.io/lego/dns/vegadns/)                          | [Vercel](https://go-acme.github.io/lego/dns/vercel/)                            |
+| [Versio.[nl/eu/uk]](https://go-acme.github.io/lego/dns/versio/)                 | [VinylDNS](https://go-acme.github.io/lego/dns/vinyldns/)                        | [VK Cloud](https://go-acme.github.io/lego/dns/vkcloud/)                         | [Vscale](https://go-acme.github.io/lego/dns/vscale/)                            |
+| [Vultr](https://go-acme.github.io/lego/dns/vultr/)                              | [Websupport](https://go-acme.github.io/lego/dns/websupport/)                    | [WEDOS](https://go-acme.github.io/lego/dns/wedos/)                              | [Yandex Cloud](https://go-acme.github.io/lego/dns/yandexcloud/)                 |
+| [Yandex PDD](https://go-acme.github.io/lego/dns/yandex/)                        | [Zone.ee](https://go-acme.github.io/lego/dns/zoneee/)                           | [Zonomi](https://go-acme.github.io/lego/dns/zonomi/)                            |                                                                                 |
+
+<!-- END DNS PROVIDERS LIST -->
+
+If your DNS provider is not supported, please open an [issue](https://github.com/go-acme/lego/issues/new?assignees=&labels=enhancement%2C+new-provider&template=new_dns_provider.md).

acme/api/account.go

@@ -0,0 +1,85 @@
+package api
+
+import (
+	"encoding/base64"
+	"errors"
+	"fmt"
+
+	"github.com/go-acme/lego/v4/acme"
+)
+
+type AccountService service
+
+// New Creates a new account.
+func (a *AccountService) New(req acme.Account) (acme.ExtendedAccount, error) {
+	var account acme.Account
+	resp, err := a.core.post(a.core.GetDirectory().NewAccountURL, req, &account)
+	location := getLocation(resp)
+
+	if len(location) > 0 {
+		a.core.jws.SetKid(location)
+	}
+
+	if err != nil {
+		return acme.ExtendedAccount{Location: location}, err
+	}
+
+	return acme.ExtendedAccount{Account: account, Location: location}, nil
+}
+
+// NewEAB Creates a new account with an External Account Binding.
+func (a *AccountService) NewEAB(accMsg acme.Account, kid, hmacEncoded string) (acme.ExtendedAccount, error) {
+	hmac, err := base64.RawURLEncoding.DecodeString(hmacEncoded)
+	if err != nil {
+		return acme.ExtendedAccount{}, fmt.Errorf("acme: could not decode hmac key: %w", err)
+	}
+
+	eabJWS, err := a.core.signEABContent(a.core.GetDirectory().NewAccountURL, kid, hmac)
+	if err != nil {
+		return acme.ExtendedAccount{}, fmt.Errorf("acme: error signing eab content: %w", err)
+	}
+
+	accMsg.ExternalAccountBinding = eabJWS
+
+	return a.New(accMsg)
+}
+
+// Get Retrieves an account.
+func (a *AccountService) Get(accountURL string) (acme.Account, error) {
+	if accountURL == "" {
+		return acme.Account{}, errors.New("account[get]: empty URL")
+	}
+
+	var account acme.Account
+	_, err := a.core.postAsGet(accountURL, &account)
+	if err != nil {
+		return acme.Account{}, err
+	}
+	return account, nil
+}
+
+// Update Updates an account.
+func (a *AccountService) Update(accountURL string, req acme.Account) (acme.Account, error) {
+	if accountURL == "" {
+		return acme.Account{}, errors.New("account[update]: empty URL")
+	}
+
+	var account acme.Account
+	_, err := a.core.post(accountURL, req, &account)
+	if err != nil {
+		return acme.Account{}, err
+	}
+
+	return account, nil
+}
+
+// Deactivate Deactivates an account.
+func (a *AccountService) Deactivate(accountURL string) error {
+	if accountURL == "" {
+		return errors.New("account[deactivate]: empty URL")
+	}
+
+	req := acme.Account{Status: acme.StatusDeactivated}
+	_, err := a.core.post(accountURL, req, nil)
+	return err
+}

acme/api/api.go

@@ -0,0 +1,165 @@
+package api
+
+import (
+	"bytes"
+	"crypto"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"net/http"
+	"time"
+
+	"github.com/cenkalti/backoff/v4"
+	"github.com/go-acme/lego/v4/acme"
+	"github.com/go-acme/lego/v4/acme/api/internal/nonces"
+	"github.com/go-acme/lego/v4/acme/api/internal/secure"
+	"github.com/go-acme/lego/v4/acme/api/internal/sender"
+	"github.com/go-acme/lego/v4/log"
+)
+
+// Core ACME/LE core API.
+type Core struct {
+	doer         *sender.Doer
+	nonceManager *nonces.Manager
+	jws          *secure.JWS
+	directory    acme.Directory
+	HTTPClient   *http.Client
+
+	common         service // Reuse a single struct instead of allocating one for each service on the heap.
+	Accounts       *AccountService
+	Authorizations *AuthorizationService
+	Certificates   *CertificateService
+	Challenges     *ChallengeService
+	Orders         *OrderService
+}
+
+// New Creates a new Core.
+func New(httpClient *http.Client, userAgent, caDirURL, kid string, privateKey crypto.PrivateKey) (*Core, error) {
+	doer := sender.NewDoer(httpClient, userAgent)
+
+	dir, err := getDirectory(doer, caDirURL)
+	if err != nil {
+		return nil, err
+	}
+
+	nonceManager := nonces.NewManager(doer, dir.NewNonceURL)
+
+	jws := secure.NewJWS(privateKey, kid, nonceManager)
+
+	c := &Core{doer: doer, nonceManager: nonceManager, jws: jws, directory: dir, HTTPClient: httpClient}
+
+	c.common.core = c
+	c.Accounts = (*AccountService)(&c.common)
+	c.Authorizations = (*AuthorizationService)(&c.common)
+	c.Certificates = (*CertificateService)(&c.common)
+	c.Challenges = (*ChallengeService)(&c.common)
+	c.Orders = (*OrderService)(&c.common)
+
+	return c, nil
+}
+
+// post performs an HTTP POST request and parses the response body as JSON,
+// into the provided respBody object.
+func (a *Core) post(uri string, reqBody, response interface{}) (*http.Response, error) {
+	content, err := json.Marshal(reqBody)
+	if err != nil {
+		return nil, errors.New("failed to marshal message")
+	}
+
+	return a.retrievablePost(uri, content, response)
+}
+
+// postAsGet performs an HTTP POST ("POST-as-GET") request.
+// https://www.rfc-editor.org/rfc/rfc8555.html#section-6.3
+func (a *Core) postAsGet(uri string, response interface{}) (*http.Response, error) {
+	return a.retrievablePost(uri, []byte{}, response)
+}
+
+func (a *Core) retrievablePost(uri string, content []byte, response interface{}) (*http.Response, error) {
+	// during tests, allow to support ~90% of bad nonce with a minimum of attempts.
+	bo := backoff.NewExponentialBackOff()
+	bo.InitialInterval = 200 * time.Millisecond
+	bo.MaxInterval = 5 * time.Second
+	bo.MaxElapsedTime = 20 * time.Second
+
+	var resp *http.Response
+	operation := func() error {
+		var err error
+		resp, err = a.signedPost(uri, content, response)
+		if err != nil {
+			// Retry if the nonce was invalidated
+			var e *acme.NonceError
+			if errors.As(err, &e) {
+				return err
+			}
+
+			return backoff.Permanent(err)
+		}
+
+		return nil
+	}
+
+	notify := func(err error, duration time.Duration) {
+		log.Infof("retry due to: %v", err)
+	}
+
+	err := backoff.RetryNotify(operation, bo, notify)
+	if err != nil {
+		return resp, err
+	}
+
+	return resp, nil
+}
+
+func (a *Core) signedPost(uri string, content []byte, response interface{}) (*http.Response, error) {
+	signedContent, err := a.jws.SignContent(uri, content)
+	if err != nil {
+		return nil, fmt.Errorf("failed to post JWS message: failed to sign content: %w", err)
+	}
+
+	signedBody := bytes.NewBufferString(signedContent.FullSerialize())
+
+	resp, err := a.doer.Post(uri, signedBody, "application/jose+json", response)
+
+	// nonceErr is ignored to keep the root error.
+	nonce, nonceErr := nonces.GetFromResponse(resp)
+	if nonceErr == nil {
+		a.nonceManager.Push(nonce)
+	}
+
+	return resp, err
+}
+
+func (a *Core) signEABContent(newAccountURL, kid string, hmac []byte) ([]byte, error) {
+	eabJWS, err := a.jws.SignEABContent(newAccountURL, kid, hmac)
+	if err != nil {
+		return nil, err
+	}
+
+	return []byte(eabJWS.FullSerialize()), nil
+}
+
+// GetKeyAuthorization Gets the key authorization.
+func (a *Core) GetKeyAuthorization(token string) (string, error) {
+	return a.jws.GetKeyAuthorization(token)
+}
+
+func (a *Core) GetDirectory() acme.Directory {
+	return a.directory
+}
+
+func getDirectory(do *sender.Doer, caDirURL string) (acme.Directory, error) {
+	var dir acme.Directory
+	if _, err := do.Get(caDirURL, &dir); err != nil {
+		return dir, fmt.Errorf("get directory at '%s': %w", caDirURL, err)
+	}
+
+	if dir.NewAccountURL == "" {
+		return dir, errors.New("directory missing new registration URL")
+	}
+	if dir.NewOrderURL == "" {
+		return dir, errors.New("directory missing new order URL")
+	}
+
+	return dir, nil
+}

acme/api/authorization.go

@@ -0,0 +1,34 @@
+package api
+
+import (
+	"errors"
+
+	"github.com/go-acme/lego/v4/acme"
+)
+
+type AuthorizationService service
+
+// Get Gets an authorization.
+func (c *AuthorizationService) Get(authzURL string) (acme.Authorization, error) {
+	if authzURL == "" {
+		return acme.Authorization{}, errors.New("authorization[get]: empty URL")
+	}
+
+	var authz acme.Authorization
+	_, err := c.core.postAsGet(authzURL, &authz)
+	if err != nil {
+		return acme.Authorization{}, err
+	}
+	return authz, nil
+}
+
+// Deactivate Deactivates an authorization.
+func (c *AuthorizationService) Deactivate(authzURL string) error {
+	if authzURL == "" {
+		return errors.New("authorization[deactivate]: empty URL")
+	}
+
+	var disabledAuth acme.Authorization
+	_, err := c.core.post(authzURL, acme.Authorization{Status: acme.StatusDeactivated}, &disabledAuth)
+	return err
+}

acme/api/certificate.go

@@ -0,0 +1,138 @@
+package api
+
+import (
+	"bytes"
+	"crypto/x509"
+	"encoding/pem"
+	"errors"
+	"io"
+	"net/http"
+
+	"github.com/go-acme/lego/v4/acme"
+	"github.com/go-acme/lego/v4/certcrypto"
+	"github.com/go-acme/lego/v4/log"
+)
+
+// maxBodySize is the maximum size of body that we will read.
+const maxBodySize = 1024 * 1024
+
+type CertificateService service
+
+// Get Returns the certificate and the issuer certificate.
+// 'bundle' is only applied if the issuer is provided by the 'up' link.
+func (c *CertificateService) Get(certURL string, bundle bool) ([]byte, []byte, error) {
+	cert, _, err := c.get(certURL, bundle)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	return cert.Cert, cert.Issuer, nil
+}
+
+// GetAll the certificates and the alternate certificates.
+// bundle' is only applied if the issuer is provided by the 'up' link.
+func (c *CertificateService) GetAll(certURL string, bundle bool) (map[string]*acme.RawCertificate, error) {
+	cert, headers, err := c.get(certURL, bundle)
+	if err != nil {
+		return nil, err
+	}
+
+	certs := map[string]*acme.RawCertificate{certURL: cert}
+
+	// URLs of "alternate" link relation
+	// - https://www.rfc-editor.org/rfc/rfc8555.html#section-7.4.2
+	alts := getLinks(headers, "alternate")
+
+	for _, alt := range alts {
+		altCert, _, err := c.get(alt, bundle)
+		if err != nil {
+			return nil, err
+		}
+
+		certs[alt] = altCert
+	}
+
+	return certs, nil
+}
+
+// Revoke Revokes a certificate.
+func (c *CertificateService) Revoke(req acme.RevokeCertMessage) error {
+	_, err := c.core.post(c.core.GetDirectory().RevokeCertURL, req, nil)
+	return err
+}
+
+// get Returns the certificate and the "up" link.
+func (c *CertificateService) get(certURL string, bundle bool) (*acme.RawCertificate, http.Header, error) {
+	if certURL == "" {
+		return nil, nil, errors.New("certificate[get]: empty URL")
+	}
+
+	resp, err := c.core.postAsGet(certURL, nil)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	data, err := io.ReadAll(http.MaxBytesReader(nil, resp.Body, maxBodySize))
+	if err != nil {
+		return nil, resp.Header, err
+	}
+
+	cert := c.getCertificateChain(data, resp.Header, bundle, certURL)
+
+	return cert, resp.Header, err
+}
+
+// getCertificateChain Returns the certificate and the issuer certificate.
+func (c *CertificateService) getCertificateChain(cert []byte, headers http.Header, bundle bool, certURL string) *acme.RawCertificate {
+	// Get issuerCert from bundled response from Let's Encrypt
+	// See https://community.letsencrypt.org/t/acme-v2-no-up-link-in-response/64962
+	_, issuer := pem.Decode(cert)
+	if issuer != nil {
+		// If bundle is false, we want to return a single certificate.
+		// To do this, we remove the issuer cert(s) from the issued cert.
+		if !bundle {
+			cert = bytes.TrimSuffix(cert, issuer)
+		}
+		return &acme.RawCertificate{Cert: cert, Issuer: issuer}
+	}
+
+	// The issuer certificate link may be supplied via an "up" link
+	// in the response headers of a new certificate.
+	// See https://www.rfc-editor.org/rfc/rfc8555.html#section-7.4.2
+	up := getLink(headers, "up")
+
+	issuer, err := c.getIssuerFromLink(up)
+	if err != nil {
+		// If we fail to acquire the issuer cert, return the issued certificate - do not fail.
+		log.Warnf("acme: Could not bundle issuer certificate [%s]: %v", certURL, err)
+	} else if len(issuer) > 0 {
+		// If bundle is true, we want to return a certificate bundle.
+		// To do this, we append the issuer cert to the issued cert.
+		if bundle {
+			cert = append(cert, issuer...)
+		}
+	}
+
+	return &acme.RawCertificate{Cert: cert, Issuer: issuer}
+}
+
+// getIssuerFromLink requests the issuer certificate.
+func (c *CertificateService) getIssuerFromLink(up string) ([]byte, error) {
+	if up == "" {
+		return nil, nil
+	}
+
+	log.Infof("acme: Requesting issuer cert from %s", up)
+
+	cert, _, err := c.get(up, false)
+	if err != nil {
+		return nil, err
+	}
+
+	_, err = x509.ParseCertificate(cert.Cert)
+	if err != nil {
+		return nil, err
+	}
+
+	return certcrypto.PEMEncode(certcrypto.DERCertificateBytes(cert.Cert)), nil
+}

acme/api/certificate_test.go

@@ -0,0 +1,130 @@
+package api
+
+import (
+	"crypto/rand"
+	"crypto/rsa"
+	"encoding/pem"
+	"net/http"
+	"testing"
+
+	"github.com/go-acme/lego/v4/platform/tester"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+const certResponseMock = `-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----
+`
+
+const issuerMock = `-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----
+`
+
+func TestCertificateService_Get_issuerRelUp(t *testing.T) {
+	mux, apiURL := tester.SetupFakeAPI(t)
+
+	mux.HandleFunc("/certificate", func(w http.ResponseWriter, _ *http.Request) {
+		w.Header().Set("Link", "<"+apiURL+`/issuer>; rel="up"`)
+		_, err := w.Write([]byte(certResponseMock))
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+	})
+
+	mux.HandleFunc("/issuer", func(w http.ResponseWriter, _ *http.Request) {
+		p, _ := pem.Decode([]byte(issuerMock))
+		_, err := w.Write(p.Bytes)
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+	})
+
+	key, err := rsa.GenerateKey(rand.Reader, 2048)
+	require.NoError(t, err, "Could not generate test key")
+
+	core, err := New(http.DefaultClient, "lego-test", apiURL+"/dir", "", key)
+	require.NoError(t, err)
+
+	cert, issuer, err := core.Certificates.Get(apiURL+"/certificate", true)
+	require.NoError(t, err)
+	assert.Equal(t, certResponseMock, string(cert), "Certificate")
+	assert.Equal(t, issuerMock, string(issuer), "IssuerCertificate")
+}
+
+func TestCertificateService_Get_embeddedIssuer(t *testing.T) {
+	mux, apiURL := tester.SetupFakeAPI(t)
+
+	mux.HandleFunc("/certificate", func(w http.ResponseWriter, _ *http.Request) {
+		_, err := w.Write([]byte(certResponseMock))
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+	})
+
+	key, err := rsa.GenerateKey(rand.Reader, 2048)
+	require.NoError(t, err, "Could not generate test key")
+
+	core, err := New(http.DefaultClient, "lego-test", apiURL+"/dir", "", key)
+	require.NoError(t, err)
+
+	cert, issuer, err := core.Certificates.Get(apiURL+"/certificate", true)
+	require.NoError(t, err)
+	assert.Equal(t, certResponseMock, string(cert), "Certificate")
+	assert.Equal(t, issuerMock, string(issuer), "IssuerCertificate")
+}

acme/api/challenge.go

@@ -0,0 +1,45 @@
+package api
+
+import (
+	"errors"
+
+	"github.com/go-acme/lego/v4/acme"
+)
+
+type ChallengeService service
+
+// New Creates a challenge.
+func (c *ChallengeService) New(chlgURL string) (acme.ExtendedChallenge, error) {
+	if chlgURL == "" {
+		return acme.ExtendedChallenge{}, errors.New("challenge[new]: empty URL")
+	}
+
+	// Challenge initiation is done by sending a JWS payload containing the trivial JSON object `{}`.
+	// We use an empty struct instance as the postJSON payload here to achieve this result.
+	var chlng acme.ExtendedChallenge
+	resp, err := c.core.post(chlgURL, struct{}{}, &chlng)
+	if err != nil {
+		return acme.ExtendedChallenge{}, err
+	}
+
+	chlng.AuthorizationURL = getLink(resp.Header, "up")
+	chlng.RetryAfter = getRetryAfter(resp)
+	return chlng, nil
+}
+
+// Get Gets a challenge.
+func (c *ChallengeService) Get(chlgURL string) (acme.ExtendedChallenge, error) {
+	if chlgURL == "" {
+		return acme.ExtendedChallenge{}, errors.New("challenge[get]: empty URL")
+	}
+
+	var chlng acme.ExtendedChallenge
+	resp, err := c.core.postAsGet(chlgURL, &chlng)
+	if err != nil {
+		return acme.ExtendedChallenge{}, err
+	}
+
+	chlng.AuthorizationURL = getLink(resp.Header, "up")
+	chlng.RetryAfter = getRetryAfter(resp)
+	return chlng, nil
+}

acme/api/internal/nonces/nonce_manager.go

@@ -0,0 +1,78 @@
+package nonces
+
+import (
+	"errors"
+	"fmt"
+	"net/http"
+	"sync"
+
+	"github.com/go-acme/lego/v4/acme/api/internal/sender"
+)
+
+// Manager Manages nonces.
+type Manager struct {
+	do       *sender.Doer
+	nonceURL string
+	nonces   []string
+	sync.Mutex
+}
+
+// NewManager Creates a new Manager.
+func NewManager(do *sender.Doer, nonceURL string) *Manager {
+	return &Manager{
+		do:       do,
+		nonceURL: nonceURL,
+	}
+}
+
+// Pop Pops a nonce.
+func (n *Manager) Pop() (string, bool) {
+	n.Lock()
+	defer n.Unlock()
+
+	if len(n.nonces) == 0 {
+		return "", false
+	}
+
+	nonce := n.nonces[len(n.nonces)-1]
+	n.nonces = n.nonces[:len(n.nonces)-1]
+	return nonce, true
+}
+
+// Push Pushes a nonce.
+func (n *Manager) Push(nonce string) {
+	n.Lock()
+	defer n.Unlock()
+	n.nonces = append(n.nonces, nonce)
+}
+
+// Nonce implement jose.NonceSource.
+func (n *Manager) Nonce() (string, error) {
+	if nonce, ok := n.Pop(); ok {
+		return nonce, nil
+	}
+	return n.getNonce()
+}
+
+func (n *Manager) getNonce() (string, error) {
+	resp, err := n.do.Head(n.nonceURL)
+	if err != nil {
+		return "", fmt.Errorf("failed to get nonce from HTTP HEAD: %w", err)
+	}
+
+	return GetFromResponse(resp)
+}
+
+// GetFromResponse Extracts a nonce from a HTTP response.
+func GetFromResponse(resp *http.Response) (string, error) {
+	if resp == nil {
+		return "", errors.New("nil response")
+	}
+
+	nonce := resp.Header.Get("Replay-Nonce")
+	if nonce == "" {
+		return "", errors.New("server did not respond with a proper nonce header")
+	}
+
+	return nonce, nil
+}

acme/api/internal/nonces/nonce_manager_test.go

@@ -0,0 +1,55 @@
+package nonces
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+	"time"
+
+	"github.com/go-acme/lego/v4/acme"
+	"github.com/go-acme/lego/v4/acme/api/internal/sender"
+	"github.com/go-acme/lego/v4/platform/tester"
+)
+
+func TestNotHoldingLockWhileMakingHTTPRequests(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		time.Sleep(250 * time.Millisecond)
+		w.Header().Set("Replay-Nonce", "12345")
+		w.Header().Set("Retry-After", "0")
+		err := tester.WriteJSONResponse(w, &acme.Challenge{Type: "http-01", Status: "Valid", URL: "http://example.com/", Token: "token"})
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+	}))
+	t.Cleanup(server.Close)
+
+	doer := sender.NewDoer(http.DefaultClient, "lego-test")
+	j := NewManager(doer, server.URL)
+	ch := make(chan bool)
+	resultCh := make(chan bool)
+	go func() {
+		_, errN := j.Nonce()
+		if errN != nil {
+			t.Log(errN)
+		}
+		ch <- true
+	}()
+	go func() {
+		_, errN := j.Nonce()
+		if errN != nil {
+			t.Log(errN)
+		}
+		ch <- true
+	}()
+	go func() {
+		<-ch
+		<-ch
+		resultCh <- true
+	}()
+	select {
+	case <-resultCh:
+	case <-time.After(500 * time.Millisecond):
+		t.Fatal("JWS is probably holding a lock while making HTTP request")
+	}
+}

acme/api/internal/secure/jws.go

@@ -0,0 +1,130 @@
+package secure
+
+import (
+	"crypto"
+	"crypto/ecdsa"
+	"crypto/elliptic"
+	"crypto/rsa"
+	"encoding/base64"
+	"fmt"
+
+	"github.com/go-acme/lego/v4/acme/api/internal/nonces"
+	jose "github.com/go-jose/go-jose/v3"
+)
+
+// JWS Represents a JWS.
+type JWS struct {
+	privKey crypto.PrivateKey
+	kid     string // Key identifier
+	nonces  *nonces.Manager
+}
+
+// NewJWS Create a new JWS.
+func NewJWS(privateKey crypto.PrivateKey, kid string, nonceManager *nonces.Manager) *JWS {
+	return &JWS{
+		privKey: privateKey,
+		nonces:  nonceManager,
+		kid:     kid,
+	}
+}
+
+// SetKid Sets a key identifier.
+func (j *JWS) SetKid(kid string) {
+	j.kid = kid
+}
+
+// SignContent Signs a content with the JWS.
+func (j *JWS) SignContent(url string, content []byte) (*jose.JSONWebSignature, error) {
+	var alg jose.SignatureAlgorithm
+	switch k := j.privKey.(type) {
+	case *rsa.PrivateKey:
+		alg = jose.RS256
+	case *ecdsa.PrivateKey:
+		if k.Curve == elliptic.P256() {
+			alg = jose.ES256
+		} else if k.Curve == elliptic.P384() {
+			alg = jose.ES384
+		}
+	}
+
+	signKey := jose.SigningKey{
+		Algorithm: alg,
+		Key:       jose.JSONWebKey{Key: j.privKey, KeyID: j.kid},
+	}
+
+	options := jose.SignerOptions{
+		NonceSource: j.nonces,
+		ExtraHeaders: map[jose.HeaderKey]interface{}{
+			"url": url,
+		},
+	}
+
+	if j.kid == "" {
+		options.EmbedJWK = true
+	}
+
+	signer, err := jose.NewSigner(signKey, &options)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create jose signer: %w", err)
+	}
+
+	signed, err := signer.Sign(content)
+	if err != nil {
+		return nil, fmt.Errorf("failed to sign content: %w", err)
+	}
+	return signed, nil
+}
+
+// SignEABContent Signs an external account binding content with the JWS.
+func (j *JWS) SignEABContent(url, kid string, hmac []byte) (*jose.JSONWebSignature, error) {
+	jwk := jose.JSONWebKey{Key: j.privKey}
+	jwkJSON, err := jwk.Public().MarshalJSON()
+	if err != nil {
+		return nil, fmt.Errorf("acme: error encoding eab jwk key: %w", err)
+	}
+
+	signer, err := jose.NewSigner(
+		jose.SigningKey{Algorithm: jose.HS256, Key: hmac},
+		&jose.SignerOptions{
+			EmbedJWK: false,
+			ExtraHeaders: map[jose.HeaderKey]interface{}{
+				"kid": kid,
+				"url": url,
+			},
+		},
+	)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create External Account Binding jose signer: %w", err)
+	}
+
+	signed, err := signer.Sign(jwkJSON)
+	if err != nil {
+		return nil, fmt.Errorf("failed to External Account Binding sign content: %w", err)
+	}
+
+	return signed, nil
+}
+
+// GetKeyAuthorization Gets the key authorization for a token.
+func (j *JWS) GetKeyAuthorization(token string) (string, error) {
+	var publicKey crypto.PublicKey
+	switch k := j.privKey.(type) {
+	case *ecdsa.PrivateKey:
+		publicKey = k.Public()
+	case *rsa.PrivateKey:
+		publicKey = k.Public()
+	}
+
+	// Generate the Key Authorization for the challenge
+	jwk := &jose.JSONWebKey{Key: publicKey}
+
+	thumbBytes, err := jwk.Thumbprint(crypto.SHA256)
+	if err != nil {
+		return "", err
+	}
+
+	// unpad the base64URL
+	keyThumb := base64.RawURLEncoding.EncodeToString(thumbBytes)
+
+	return token + "." + keyThumb, nil
+}

acme/api/internal/secure/jws_test.go

@@ -0,0 +1,56 @@
+package secure
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+	"time"
+
+	"github.com/go-acme/lego/v4/acme"
+	"github.com/go-acme/lego/v4/acme/api/internal/nonces"
+	"github.com/go-acme/lego/v4/acme/api/internal/sender"
+	"github.com/go-acme/lego/v4/platform/tester"
+)
+
+func TestNotHoldingLockWhileMakingHTTPRequests(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		time.Sleep(250 * time.Millisecond)
+		w.Header().Set("Replay-Nonce", "12345")
+		w.Header().Set("Retry-After", "0")
+		err := tester.WriteJSONResponse(w, &acme.Challenge{Type: "http-01", Status: "Valid", URL: "http://example.com/", Token: "token"})
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+	}))
+	t.Cleanup(server.Close)
+
+	doer := sender.NewDoer(http.DefaultClient, "lego-test")
+	j := nonces.NewManager(doer, server.URL)
+	ch := make(chan bool)
+	resultCh := make(chan bool)
+	go func() {
+		_, errN := j.Nonce()
+		if errN != nil {
+			t.Log(errN)
+		}
+		ch <- true
+	}()
+	go func() {
+		_, errN := j.Nonce()
+		if errN != nil {
+			t.Log(errN)
+		}
+		ch <- true
+	}()
+	go func() {
+		<-ch
+		<-ch
+		resultCh <- true
+	}()
+	select {
+	case <-resultCh:
+	case <-time.After(500 * time.Millisecond):
+		t.Fatal("JWS is probably holding a lock while making HTTP request")
+	}
+}

acme/api/internal/sender/sender.go

@@ -0,0 +1,148 @@
+package sender
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"runtime"
+	"strings"
+
+	"github.com/go-acme/lego/v4/acme"
+)
+
+type RequestOption func(*http.Request) error
+
+func contentType(ct string) RequestOption {
+	return func(req *http.Request) error {
+		req.Header.Set("Content-Type", ct)
+		return nil
+	}
+}
+
+type Doer struct {
+	httpClient *http.Client
+	userAgent  string
+}
+
+// NewDoer Creates a new Doer.
+func NewDoer(client *http.Client, userAgent string) *Doer {
+	return &Doer{
+		httpClient: client,
+		userAgent:  userAgent,
+	}
+}
+
+// Get performs a GET request with a proper User-Agent string.
+// If "response" is not provided, callers should close resp.Body when done reading from it.
+func (d *Doer) Get(url string, response interface{}) (*http.Response, error) {
+	req, err := d.newRequest(http.MethodGet, url, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	return d.do(req, response)
+}
+
+// Head performs a HEAD request with a proper User-Agent string.
+// The response body (resp.Body) is already closed when this function returns.
+func (d *Doer) Head(url string) (*http.Response, error) {
+	req, err := d.newRequest(http.MethodHead, url, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	return d.do(req, nil)
+}
+
+// Post performs a POST request with a proper User-Agent string.
+// If "response" is not provided, callers should close resp.Body when done reading from it.
+func (d *Doer) Post(url string, body io.Reader, bodyType string, response interface{}) (*http.Response, error) {
+	req, err := d.newRequest(http.MethodPost, url, body, contentType(bodyType))
+	if err != nil {
+		return nil, err
+	}
+
+	return d.do(req, response)
+}
+
+func (d *Doer) newRequest(method, uri string, body io.Reader, opts ...RequestOption) (*http.Request, error) {
+	req, err := http.NewRequest(method, uri, body)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create request: %w", err)
+	}
+
+	req.Header.Set("User-Agent", d.formatUserAgent())
+
+	for _, opt := range opts {
+		err = opt(req)
+		if err != nil {
+			return nil, fmt.Errorf("failed to create request: %w", err)
+		}
+	}
+
+	return req, nil
+}
+
+func (d *Doer) do(req *http.Request, response interface{}) (*http.Response, error) {
+	resp, err := d.httpClient.Do(req)
+	if err != nil {
+		return nil, err
+	}
+
+	if err = checkError(req, resp); err != nil {
+		return resp, err
+	}
+
+	if response != nil {
+		raw, err := io.ReadAll(resp.Body)
+		if err != nil {
+			return resp, err
+		}
+
+		defer resp.Body.Close()
+
+		err = json.Unmarshal(raw, response)
+		if err != nil {
+			return resp, fmt.Errorf("failed to unmarshal %q to type %T: %w", raw, response, err)
+		}
+	}
+
+	return resp, nil
+}
+
+// formatUserAgent builds and returns the User-Agent string to use in requests.
+func (d *Doer) formatUserAgent() string {
+	ua := fmt.Sprintf("%s %s (%s; %s; %s)", d.userAgent, ourUserAgent, ourUserAgentComment, runtime.GOOS, runtime.GOARCH)
+	return strings.TrimSpace(ua)
+}
+
+func checkError(req *http.Request, resp *http.Response) error {
+	if resp.StatusCode >= http.StatusBadRequest {
+		body, err := io.ReadAll(resp.Body)
+		if err != nil {
+			return fmt.Errorf("%d :: %s :: %s :: %w", resp.StatusCode, req.Method, req.URL, err)
+		}
+
+		var errorDetails *acme.ProblemDetails
+		err = json.Unmarshal(body, &errorDetails)
+		if err != nil {
+			return fmt.Errorf("%d ::%s :: %s :: %w :: %s", resp.StatusCode, req.Method, req.URL, err, string(body))
+		}
+
+		errorDetails.Method = req.Method
+		errorDetails.URL = req.URL.String()
+
+		if errorDetails.HTTPStatus == 0 {
+			errorDetails.HTTPStatus = resp.StatusCode
+		}
+
+		// Check for errors we handle specifically
+		if errorDetails.HTTPStatus == http.StatusBadRequest && errorDetails.Type == acme.BadNonceErr {
+			return &acme.NonceError{ProblemDetails: errorDetails}
+		}
+
+		return errorDetails
+	}
+	return nil
+}

acme/api/internal/sender/sender_test.go

@@ -0,0 +1,67 @@
+package sender
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestDo_UserAgentOnAllHTTPMethod(t *testing.T) {
+	var ua, method string
+	server := httptest.NewServer(http.HandlerFunc(func(_ http.ResponseWriter, r *http.Request) {
+		ua = r.Header.Get("User-Agent")
+		method = r.Method
+	}))
+	t.Cleanup(server.Close)
+
+	doer := NewDoer(http.DefaultClient, "")
+
+	testCases := []struct {
+		method string
+		call   func(u string) (*http.Response, error)
+	}{
+		{
+			method: http.MethodGet,
+			call: func(u string) (*http.Response, error) {
+				return doer.Get(u, nil)
+			},
+		},
+		{
+			method: http.MethodHead,
+			call:   doer.Head,
+		},
+		{
+			method: http.MethodPost,
+			call: func(u string) (*http.Response, error) {
+				return doer.Post(u, strings.NewReader("falalalala"), "text/plain", nil)
+			},
+		},
+	}
+
+	for _, test := range testCases {
+		t.Run(test.method, func(t *testing.T) {
+			_, err := test.call(server.URL)
+			require.NoError(t, err)
+
+			assert.Equal(t, test.method, method)
+			assert.Contains(t, ua, ourUserAgent, "User-Agent")
+		})
+	}
+}
+
+func TestDo_CustomUserAgent(t *testing.T) {
+	customUA := "MyApp/1.2.3"
+	doer := NewDoer(http.DefaultClient, customUA)
+
+	ua := doer.formatUserAgent()
+	assert.Contains(t, ua, ourUserAgent)
+	assert.Contains(t, ua, customUA)
+	if strings.HasSuffix(ua, " ") {
+		t.Errorf("UA should not have trailing spaces; got '%s'", ua)
+	}
+	assert.Len(t, strings.Split(ua, " "), 5)
+}

acme/api/internal/sender/useragent.go

@@ -0,0 +1,14 @@
+package sender
+
+// CODE GENERATED AUTOMATICALLY
+// THIS FILE MUST NOT BE EDITED BY HAND
+
+const (
+	// ourUserAgent is the User-Agent of this underlying library package.
+	ourUserAgent = "xenolf-acme/4.13.2"
+
+	// ourUserAgentComment is part of the UA comment linked to the version status of this underlying library package.
+	// values: detach|release
+	// NOTE: Update this with each tagged release.
+	ourUserAgentComment = "detach"
+)

acme/api/order.go

@@ -0,0 +1,94 @@
+package api
+
+import (
+	"encoding/base64"
+	"errors"
+	"net"
+	"time"
+
+	"github.com/go-acme/lego/v4/acme"
+)
+
+// OrderOptions used to create an order (optional).
+type OrderOptions struct {
+	NotBefore time.Time
+	NotAfter  time.Time
+}
+
+type OrderService service
+
+// New Creates a new order.
+func (o *OrderService) New(domains []string) (acme.ExtendedOrder, error) {
+	return o.NewWithOptions(domains, nil)
+}
+
+// NewWithOptions Creates a new order.
+func (o *OrderService) NewWithOptions(domains []string, opts *OrderOptions) (acme.ExtendedOrder, error) {
+	var identifiers []acme.Identifier
+	for _, domain := range domains {
+		ident := acme.Identifier{Value: domain, Type: "dns"}
+
+		if net.ParseIP(domain) != nil {
+			ident.Type = "ip"
+		}
+
+		identifiers = append(identifiers, ident)
+	}
+
+	orderReq := acme.Order{Identifiers: identifiers}
+
+	if opts != nil {
+		if !opts.NotAfter.IsZero() {
+			orderReq.NotAfter = opts.NotAfter.Format(time.RFC3339)
+		}
+
+		if !opts.NotBefore.IsZero() {
+			orderReq.NotBefore = opts.NotBefore.Format(time.RFC3339)
+		}
+	}
+
+	var order acme.Order
+	resp, err := o.core.post(o.core.GetDirectory().NewOrderURL, orderReq, &order)
+	if err != nil {
+		return acme.ExtendedOrder{}, err
+	}
+
+	return acme.ExtendedOrder{
+		Order:    order,
+		Location: resp.Header.Get("Location"),
+	}, nil
+}
+
+// Get Gets an order.
+func (o *OrderService) Get(orderURL string) (acme.ExtendedOrder, error) {
+	if orderURL == "" {
+		return acme.ExtendedOrder{}, errors.New("order[get]: empty URL")
+	}
+
+	var order acme.Order
+	_, err := o.core.postAsGet(orderURL, &order)
+	if err != nil {
+		return acme.ExtendedOrder{}, err
+	}
+
+	return acme.ExtendedOrder{Order: order}, nil
+}
+
+// UpdateForCSR Updates an order for a CSR.
+func (o *OrderService) UpdateForCSR(orderURL string, csr []byte) (acme.ExtendedOrder, error) {
+	csrMsg := acme.CSRMessage{
+		Csr: base64.RawURLEncoding.EncodeToString(csr),
+	}
+
+	var order acme.Order
+	_, err := o.core.post(orderURL, csrMsg, &order)
+	if err != nil {
+		return acme.ExtendedOrder{}, err
+	}
+
+	if order.Status == acme.StatusInvalid {
+		return acme.ExtendedOrder{}, order.Error
+	}
+
+	return acme.ExtendedOrder{Order: order}, nil
+}

acme/api/order_test.go

@@ -0,0 +1,129 @@
+package api
+
+import (
+	"crypto/rand"
+	"crypto/rsa"
+	"encoding/json"
+	"io"
+	"net/http"
+	"testing"
+	"time"
+
+	"github.com/go-acme/lego/v4/acme"
+	"github.com/go-acme/lego/v4/platform/tester"
+	"github.com/go-jose/go-jose/v3"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestOrderService_NewWithOptions(t *testing.T) {
+	mux, apiURL := tester.SetupFakeAPI(t)
+
+	// small value keeps test fast
+	privateKey, errK := rsa.GenerateKey(rand.Reader, 512)
+	require.NoError(t, errK, "Could not generate test key")
+
+	mux.HandleFunc("/newOrder", func(w http.ResponseWriter, r *http.Request) {
+		if r.Method != http.MethodPost {
+			http.Error(w, http.StatusText(http.StatusMethodNotAllowed), http.StatusMethodNotAllowed)
+			return
+		}
+
+		body, err := readSignedBody(r, privateKey)
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusBadRequest)
+			return
+		}
+
+		order := acme.Order{}
+		err = json.Unmarshal(body, &order)
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusBadRequest)
+			return
+		}
+
+		err = tester.WriteJSONResponse(w, acme.Order{
+			Status:         acme.StatusValid,
+			Expires:        order.Expires,
+			Identifiers:    order.Identifiers,
+			NotBefore:      order.NotBefore,
+			NotAfter:       order.NotAfter,
+			Error:          order.Error,
+			Authorizations: order.Authorizations,
+			Finalize:       order.Finalize,
+			Certificate:    order.Certificate,
+		})
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+	})
+
+	core, err := New(http.DefaultClient, "lego-test", apiURL+"/dir", "", privateKey)
+	require.NoError(t, err)
+
+	testCases := []struct {
+		desc     string
+		opts     *OrderOptions
+		expected acme.ExtendedOrder
+	}{
+		{
+			desc: "simple",
+			expected: acme.ExtendedOrder{
+				Order: acme.Order{
+					Status:      "valid",
+					Identifiers: []acme.Identifier{{Type: "dns", Value: "example.com"}},
+				},
+			},
+		},
+		{
+			desc: "with options",
+			opts: &OrderOptions{
+				NotBefore: time.Date(2023, 1, 1, 1, 0, 0, 0, time.UTC),
+				NotAfter:  time.Date(2023, 1, 2, 1, 0, 0, 0, time.UTC),
+			},
+			expected: acme.ExtendedOrder{
+				Order: acme.Order{
+					Status:      "valid",
+					Identifiers: []acme.Identifier{{Type: "dns", Value: "example.com"}},
+					NotBefore:   "2023-01-01T01:00:00Z",
+					NotAfter:    "2023-01-02T01:00:00Z",
+				},
+			},
+		},
+	}
+
+	for _, test := range testCases {
+		test := test
+		t.Run(test.desc, func(t *testing.T) {
+			t.Parallel()
+
+			order, err := core.Orders.NewWithOptions([]string{"example.com"}, test.opts)
+			require.NoError(t, err)
+
+			assert.Equal(t, test.expected, order)
+		})
+	}
+}
+
+func readSignedBody(r *http.Request, privateKey *rsa.PrivateKey) ([]byte, error) {
+	reqBody, err := io.ReadAll(r.Body)
+	if err != nil {
+		return nil, err
+	}
+
+	jws, err := jose.ParseSigned(string(reqBody))
+	if err != nil {
+		return nil, err
+	}
+
+	body, err := jws.Verify(&jose.JSONWebKey{
+		Key:       privateKey.Public(),
+		Algorithm: "RSA",
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	return body, nil
+}

acme/api/renewal.go

@@ -0,0 +1,53 @@
+package api
+
+import (
+	"errors"
+	"net/http"
+
+	"github.com/go-acme/lego/v4/acme"
+)
+
+// ErrNoARI is returned when the server does not advertise a renewal info endpoint.
+var ErrNoARI = errors.New("renewalInfo[get/post]: server does not advertise a renewal info endpoint")
+
+// GetRenewalInfo GETs renewal information for a certificate from the renewalInfo endpoint.
+// This is used to determine if a certificate needs to be renewed.
+//
+// Note: this endpoint is part of a draft specification, not all ACME servers will implement it.
+// This method will return api.ErrNoARI if the server does not advertise a renewal info endpoint.
+//
+// https://datatracker.ietf.org/doc/draft-ietf-acme-ari
+func (c *CertificateService) GetRenewalInfo(certID string) (*http.Response, error) {
+	if c.core.GetDirectory().RenewalInfo == "" {
+		return nil, ErrNoARI
+	}
+
+	if certID == "" {
+		return nil, errors.New("renewalInfo[get]: 'certID' cannot be empty")
+	}
+
+	return c.core.HTTPClient.Get(c.core.GetDirectory().RenewalInfo + "/" + certID)
+}
+
+// UpdateRenewalInfo POSTs updated renewal information for a certificate to the renewalInfo endpoint.
+// This is used to indicate that a certificate has been replaced.
+//
+// Note: this endpoint is part of a draft specification, not all ACME servers will implement it.
+// This method will return api.ErrNoARI if the server does not advertise a renewal info endpoint.
+//
+// https://datatracker.ietf.org/doc/draft-ietf-acme-ari
+func (c *CertificateService) UpdateRenewalInfo(req acme.RenewalInfoUpdateRequest) (*http.Response, error) {
+	if c.core.GetDirectory().RenewalInfo == "" {
+		return nil, ErrNoARI
+	}
+
+	if req.CertID == "" {
+		return nil, errors.New("renewalInfo[post]: 'certID' cannot be empty")
+	}
+
+	if !req.Replaced {
+		return nil, errors.New("renewalInfo[post]: 'replaced' cannot be false")
+	}
+
+	return c.core.post(c.core.GetDirectory().RenewalInfo, req, nil)
+}

acme/api/service.go

@@ -0,0 +1,56 @@
+package api
+
+import (
+	"net/http"
+	"regexp"
+)
+
+type service struct {
+	core *Core
+}
+
+// getLink get a rel into the Link header.
+func getLink(header http.Header, rel string) string {
+	links := getLinks(header, rel)
+	if len(links) < 1 {
+		return ""
+	}
+
+	return links[0]
+}
+
+func getLinks(header http.Header, rel string) []string {
+	linkExpr := regexp.MustCompile(`<(.+?)>(?:;[^;]+)*?;\s*rel="(.+?)"`)
+
+	var links []string
+	for _, link := range header["Link"] {
+		for _, m := range linkExpr.FindAllStringSubmatch(link, -1) {
+			if len(m) != 3 {
+				continue
+			}
+			if m[2] == rel {
+				links = append(links, m[1])
+			}
+		}
+	}
+
+	return links
+}
+
+// getLocation get the value of the header Location.
+func getLocation(resp *http.Response) string {
+	if resp == nil {
+		return ""
+	}
+
+	return resp.Header.Get("Location")
+}
+
+// getRetryAfter get the value of the header Retry-After.
+func getRetryAfter(resp *http.Response) string {
+	if resp == nil {
+		return ""
+	}
+
+	return resp.Header.Get("Retry-After")
+}

acme/api/service_test.go

@@ -0,0 +1,56 @@
+package api
+
+import (
+	"net/http"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func Test_getLink(t *testing.T) {
+	testCases := []struct {
+		desc     string
+		header   http.Header
+		relName  string
+		expected string
+	}{
+		{
+			desc: "success",
+			header: http.Header{
+				"Link": []string{`<https://acme-staging-v02.api.letsencrypt.org/next>; rel="next", <https://acme-staging-v02.api.letsencrypt.org/up?query>; rel="up"`},
+			},
+			relName:  "up",
+			expected: "https://acme-staging-v02.api.letsencrypt.org/up?query",
+		},
+		{
+			desc: "success several lines",
+			header: http.Header{
+				"Link": []string{`<https://acme-staging-v02.api.letsencrypt.org/next>; rel="next"`, `<https://acme-staging-v02.api.letsencrypt.org/up?query>; rel="up"`},
+			},
+			relName:  "up",
+			expected: "https://acme-staging-v02.api.letsencrypt.org/up?query",
+		},
+		{
+			desc:     "no link",
+			header:   http.Header{},
+			relName:  "up",
+			expected: "",
+		},
+		{
+			desc:     "no header",
+			relName:  "up",
+			expected: "",
+		},
+	}
+
+	for _, test := range testCases {
+		test := test
+		t.Run(test.desc, func(t *testing.T) {
+			t.Parallel()
+
+			link := getLink(test.header, test.relName)
+
+			assert.Equal(t, test.expected, link)
+		})
+	}
+}

acme/commons.go

@@ -0,0 +1,341 @@
+// Package acme contains all objects related the ACME endpoints.
+// https://www.rfc-editor.org/rfc/rfc8555.html
+package acme
+
+import (
+	"encoding/json"
+	"time"
+)
+
+// ACME status values of Account, Order, Authorization and Challenge objects.
+// See https://www.rfc-editor.org/rfc/rfc8555.html#section-7.1.6 for details.
+const (
+	StatusDeactivated = "deactivated"
+	StatusExpired     = "expired"
+	StatusInvalid     = "invalid"
+	StatusPending     = "pending"
+	StatusProcessing  = "processing"
+	StatusReady       = "ready"
+	StatusRevoked     = "revoked"
+	StatusUnknown     = "unknown"
+	StatusValid       = "valid"
+)
+
+// CRL reason codes as defined in RFC 5280.
+// https://datatracker.ietf.org/doc/html/rfc5280#section-5.3.1
+const (
+	CRLReasonUnspecified          uint = 0
+	CRLReasonKeyCompromise        uint = 1
+	CRLReasonCACompromise         uint = 2
+	CRLReasonAffiliationChanged   uint = 3
+	CRLReasonSuperseded           uint = 4
+	CRLReasonCessationOfOperation uint = 5
+	CRLReasonCertificateHold      uint = 6
+	CRLReasonRemoveFromCRL        uint = 8
+	CRLReasonPrivilegeWithdrawn   uint = 9
+	CRLReasonAACompromise         uint = 10
+)
+
+// Directory the ACME directory object.
+// - https://www.rfc-editor.org/rfc/rfc8555.html#section-7.1.1
+// - https://datatracker.ietf.org/doc/draft-ietf-acme-ari/
+type Directory struct {
+	NewNonceURL   string `json:"newNonce"`
+	NewAccountURL string `json:"newAccount"`
+	NewOrderURL   string `json:"newOrder"`
+	NewAuthzURL   string `json:"newAuthz"`
+	RevokeCertURL string `json:"revokeCert"`
+	KeyChangeURL  string `json:"keyChange"`
+	Meta          Meta   `json:"meta"`
+	RenewalInfo   string `json:"renewalInfo"`
+}
+
+// Meta the ACME meta object (related to Directory).
+// - https://www.rfc-editor.org/rfc/rfc8555.html#section-7.1.1
+type Meta struct {
+	// termsOfService (optional, string):
+	// A URL identifying the current terms of service.
+	TermsOfService string `json:"termsOfService"`
+
+	// website (optional, string):
+	// An HTTP or HTTPS URL locating a website providing more information about the ACME server.
+	Website string `json:"website"`
+
+	// caaIdentities (optional, array of string):
+	// The hostnames that the ACME server recognizes as referring to itself
+	// for the purposes of CAA record validation as defined in [RFC6844].
+	// Each string MUST represent the same sequence of ASCII code points
+	// that the server will expect to see as the "Issuer Domain Name" in a CAA issue or issuewild property tag.
+	// This allows clients to determine the correct issuer domain name to use when configuring CAA records.
+	CaaIdentities []string `json:"caaIdentities"`
+
+	// externalAccountRequired (optional, boolean):
+	// If this field is present and set to "true",
+	// then the CA requires that all new- account requests include an "externalAccountBinding" field
+	// associating the new account with an external account.
+	ExternalAccountRequired bool `json:"externalAccountRequired"`
+}
+
+// ExtendedAccount a extended Account.
+type ExtendedAccount struct {
+	Account
+	// Contains the value of the response header `Location`
+	Location string `json:"-"`
+}
+
+// Account the ACME account Object.
+// - https://www.rfc-editor.org/rfc/rfc8555.html#section-7.1.2
+// - https://www.rfc-editor.org/rfc/rfc8555.html#section-7.3
+type Account struct {
+	// status (required, string):
+	// The status of this account.
+	// Possible values are: "valid", "deactivated", and "revoked".
+	// The value "deactivated" should be used to indicate client-initiated deactivation
+	// whereas "revoked" should be used to indicate server- initiated deactivation. (See Section 7.1.6)
+	Status string `json:"status,omitempty"`
+
+	// contact (optional, array of string):
+	// An array of URLs that the server can use to contact the client for issues related to this account.
+	// For example, the server may wish to notify the client about server-initiated revocation or certificate expiration.
+	// For information on supported URL schemes, see Section 7.3
+	Contact []string `json:"contact,omitempty"`
+
+	// termsOfServiceAgreed (optional, boolean):
+	// Including this field in a new-account request,
+	// with a value of true, indicates the client's agreement with the terms of service.
+	// This field is not updateable by the client.
+	TermsOfServiceAgreed bool `json:"termsOfServiceAgreed,omitempty"`
+
+	// orders (required, string):
+	// A URL from which a list of orders submitted by this account can be fetched via a POST-as-GET request,
+	// as described in Section 7.1.2.1.
+	Orders string `json:"orders,omitempty"`
+
+	// onlyReturnExisting (optional, boolean):
+	// If this field is present with the value "true",
+	// then the server MUST NOT create a new account if one does not already exist.
+	// This allows a client to look up an account URL based on an account key (see Section 7.3.1).
+	OnlyReturnExisting bool `json:"onlyReturnExisting,omitempty"`
+
+	// externalAccountBinding (optional, object):
+	// An optional field for binding the new account with an existing non-ACME account (see Section 7.3.4).
+	ExternalAccountBinding json.RawMessage `json:"externalAccountBinding,omitempty"`
+}
+
+// ExtendedOrder a extended Order.
+type ExtendedOrder struct {
+	Order
+
+	// The order URL, contains the value of the response header `Location`
+	Location string `json:"-"`
+}
+
+// Order the ACME order Object.
+// - https://www.rfc-editor.org/rfc/rfc8555.html#section-7.1.3
+type Order struct {
+	// status (required, string):
+	// The status of this order.
+	// Possible values are: "pending", "ready", "processing", "valid", and "invalid".
+	Status string `json:"status,omitempty"`
+
+	// expires (optional, string):
+	// The timestamp after which the server will consider this order invalid,
+	// encoded in the format specified in RFC 3339 [RFC3339].
+	// This field is REQUIRED for objects with "pending" or "valid" in the status field.
+	Expires string `json:"expires,omitempty"`
+
+	// identifiers (required, array of object):
+	// An array of identifier objects that the order pertains to.
+	Identifiers []Identifier `json:"identifiers"`
+
+	// notBefore (optional, string):
+	// The requested value of the notBefore field in the certificate,
+	// in the date format defined in [RFC3339].
+	NotBefore string `json:"notBefore,omitempty"`
+
+	// notAfter (optional, string):
+	// The requested value of the notAfter field in the certificate,
+	// in the date format defined in [RFC3339].
+	NotAfter string `json:"notAfter,omitempty"`
+
+	// error (optional, object):
+	// The error that occurred while processing the order, if any.
+	// This field is structured as a problem document [RFC7807].
+	Error *ProblemDetails `json:"error,omitempty"`
+
+	// authorizations (required, array of string):
+	// For pending orders,
+	// the authorizations that the client needs to complete before the requested certificate can be issued (see Section 7.5),
+	// including unexpired authorizations that the client has completed in the past for identifiers specified in the order.
+	// The authorizations required are dictated by server policy
+	// and there may not be a 1:1 relationship between the order identifiers and the authorizations required.
+	// For final orders (in the "valid" or "invalid" state), the authorizations that were completed.
+	// Each entry is a URL from which an authorization can be fetched with a POST-as-GET request.
+	Authorizations []string `json:"authorizations,omitempty"`
+
+	// finalize (required, string):
+	// A URL that a CSR must be POSTed to once all of the order's authorizations are satisfied to finalize the order.
+	// The result of a successful finalization will be the population of the certificate URL for the order.
+	Finalize string `json:"finalize,omitempty"`
+
+	// certificate (optional, string):
+	// A URL for the certificate that has been issued in response to this order
+	Certificate string `json:"certificate,omitempty"`
+}
+
+// Authorization the ACME authorization object.
+// - https://www.rfc-editor.org/rfc/rfc8555.html#section-7.1.4
+type Authorization struct {
+	// status (required, string):
+	// The status of this authorization.
+	// Possible values are: "pending", "valid", "invalid", "deactivated", "expired", and "revoked".
+	Status string `json:"status"`
+
+	// expires (optional, string):
+	// The timestamp after which the server will consider this authorization invalid,
+	// encoded in the format specified in RFC 3339 [RFC3339].
+	// This field is REQUIRED for objects with "valid" in the "status" field.
+	Expires time.Time `json:"expires,omitempty"`
+
+	// identifier (required, object):
+	// The identifier that the account is authorized to represent
+	Identifier Identifier `json:"identifier,omitempty"`
+
+	// challenges (required, array of objects):
+	// For pending authorizations, the challenges that the client can fulfill in order to prove possession of the identifier.
+	// For valid authorizations, the challenge that was validated.
+	// For invalid authorizations, the challenge that was attempted and failed.
+	// Each array entry is an object with parameters required to validate the challenge.
+	// A client should attempt to fulfill one of these challenges,
+	// and a server should consider any one of the challenges sufficient to make the authorization valid.
+	Challenges []Challenge `json:"challenges,omitempty"`
+
+	// wildcard (optional, boolean):
+	// For authorizations created as a result of a newOrder request containing a DNS identifier
+	// with a value that contained a wildcard prefix this field MUST be present, and true.
+	Wildcard bool `json:"wildcard,omitempty"`
+}
+
+// ExtendedChallenge a extended Challenge.
+type ExtendedChallenge struct {
+	Challenge
+	// Contains the value of the response header `Retry-After`
+	RetryAfter string `json:"-"`
+	// Contains the value of the response header `Link` rel="up"
+	AuthorizationURL string `json:"-"`
+}
+
+// Challenge the ACME challenge object.
+// - https://www.rfc-editor.org/rfc/rfc8555.html#section-7.1.5
+// - https://www.rfc-editor.org/rfc/rfc8555.html#section-8
+type Challenge struct {
+	// type (required, string):
+	// The type of challenge encoded in the object.
+	Type string `json:"type"`
+
+	// url (required, string):
+	// The URL to which a response can be posted.
+	URL string `json:"url"`
+
+	// status (required, string):
+	// The status of this challenge. Possible values are: "pending", "processing", "valid", and "invalid".
+	Status string `json:"status"`
+
+	// validated (optional, string):
+	// The time at which the server validated this challenge,
+	// encoded in the format specified in RFC 3339 [RFC3339].
+	// This field is REQUIRED if the "status" field is "valid".
+	Validated time.Time `json:"validated,omitempty"`
+
+	// error (optional, object):
+	// Error that occurred while the server was validating the challenge, if any,
+	// structured as a problem document [RFC7807].
+	// Multiple errors can be indicated by using subproblems Section 6.7.1.
+	// A challenge object with an error MUST have status equal to "invalid".
+	Error *ProblemDetails `json:"error,omitempty"`
+
+	// token (required, string):
+	// A random value that uniquely identifies the challenge.
+	// This value MUST have at least 128 bits of entropy.
+	// It MUST NOT contain any characters outside the base64url alphabet,
+	// and MUST NOT include base64 padding characters ("=").
+	// See [RFC4086] for additional information on randomness requirements.
+	// https://www.rfc-editor.org/rfc/rfc8555.html#section-8.3
+	// https://www.rfc-editor.org/rfc/rfc8555.html#section-8.4
+	Token string `json:"token"`
+
+	// https://www.rfc-editor.org/rfc/rfc8555.html#section-8.1
+	KeyAuthorization string `json:"keyAuthorization"`
+}
+
+// Identifier the ACME identifier object.
+// - https://www.rfc-editor.org/rfc/rfc8555.html#section-9.7.7
+type Identifier struct {
+	Type  string `json:"type"`
+	Value string `json:"value"`
+}
+
+// CSRMessage Certificate Signing Request.
+// - https://www.rfc-editor.org/rfc/rfc8555.html#section-7.4
+type CSRMessage struct {
+	// csr (required, string):
+	// A CSR encoding the parameters for the certificate being requested [RFC2986].
+	// The CSR is sent in the base64url-encoded version of the DER format.
+	// (Note: Because this field uses base64url, and does not include headers, it is different from PEM.).
+	Csr string `json:"csr"`
+}
+
+// RevokeCertMessage a certificate revocation message.
+// - https://www.rfc-editor.org/rfc/rfc8555.html#section-7.6
+// - https://www.rfc-editor.org/rfc/rfc5280.html#section-5.3.1
+type RevokeCertMessage struct {
+	// certificate (required, string):
+	// The certificate to be revoked, in the base64url-encoded version of the DER format.
+	// (Note: Because this field uses base64url, and does not include headers, it is different from PEM.)
+	Certificate string `json:"certificate"`
+
+	// reason (optional, int):
+	// One of the revocation reasonCodes defined in Section 5.3.1 of [RFC5280] to be used when generating OCSP responses and CRLs.
+	// If this field is not set the server SHOULD omit the reasonCode CRL entry extension when generating OCSP responses and CRLs.
+	// The server MAY disallow a subset of reasonCodes from being used by the user.
+	// If a request contains a disallowed reasonCode the server MUST reject it with the error type "urn:ietf:params:acme:error:badRevocationReason".
+	// The problem document detail SHOULD indicate which reasonCodes are allowed.
+	Reason *uint `json:"reason,omitempty"`
+}
+
+// RawCertificate raw data of a certificate.
+type RawCertificate struct {
+	Cert   []byte
+	Issuer []byte
+}
+
+// Window is a window of time.
+type Window struct {
+	Start time.Time `json:"start"`
+	End   time.Time `json:"end"`
+}
+
+// RenewalInfoResponse is the response to GET requests made the renewalInfo endpoint.
+// - (4.1. Getting Renewal Information) https://datatracker.ietf.org/doc/draft-ietf-acme-ari/
+type RenewalInfoResponse struct {
+	// SuggestedWindow contains two fields, start and end,
+	// whose values are timestamps which bound the window of time in which the CA recommends renewing the certificate.
+	SuggestedWindow Window `json:"suggestedWindow"`
+	//	ExplanationURL is a optional URL pointing to a page which may explain why the suggested renewal window is what it is.
+	//	For example, it may be a page explaining the CA's dynamic load-balancing strategy,
+	//	or a page documenting which certificates are affected by a mass revocation event.
+	//	Callers SHOULD provide this URL to their operator, if present.
+	ExplanationURL string `json:"explanationURL"`
+}
+
+// RenewalInfoUpdateRequest is the JWS payload for POST requests made to the renewalInfo endpoint.
+// - (4.2. Updating Renewal Information) https://datatracker.ietf.org/doc/draft-ietf-acme-ari/
+type RenewalInfoUpdateRequest struct {
+	// CertID is the base64url-encoded [RFC4648] bytes of a DER-encoded CertID ASN.1 sequence [RFC6960] with any trailing '=' characters stripped.
+	CertID string `json:"certID"`
+	// Replaced is required and indicates whether or not the client considers the certificate to have been replaced.
+	// A certificate is considered replaced when its revocation would not disrupt any ongoing services,
+	// for instance because it has been renewed and the new certificate is in use, or because it is no longer in use.
+	// Clients SHOULD NOT send a request where this value is false.
+	Replaced bool `json:"replaced"`
+}

acme/errors.go

@@ -0,0 +1,58 @@
+package acme
+
+import (
+	"fmt"
+)
+
+// Errors types.
+const (
+	errNS       = "urn:ietf:params:acme:error:"
+	BadNonceErr = errNS + "badNonce"
+)
+
+// ProblemDetails the problem details object.
+// - https://www.rfc-editor.org/rfc/rfc7807.html#section-3.1
+// - https://www.rfc-editor.org/rfc/rfc8555.html#section-7.3.3
+type ProblemDetails struct {
+	Type        string       `json:"type,omitempty"`
+	Detail      string       `json:"detail,omitempty"`
+	HTTPStatus  int          `json:"status,omitempty"`
+	Instance    string       `json:"instance,omitempty"`
+	SubProblems []SubProblem `json:"subproblems,omitempty"`
+
+	// additional values to have a better error message (Not defined by the RFC)
+	Method string `json:"method,omitempty"`
+	URL    string `json:"url,omitempty"`
+}
+
+// SubProblem a "subproblems".
+// - https://www.rfc-editor.org/rfc/rfc8555.html#section-6.7.1
+type SubProblem struct {
+	Type       string     `json:"type,omitempty"`
+	Detail     string     `json:"detail,omitempty"`
+	Identifier Identifier `json:"identifier,omitempty"`
+}
+
+func (p ProblemDetails) Error() string {
+	msg := fmt.Sprintf("acme: error: %d", p.HTTPStatus)
+	if p.Method != "" || p.URL != "" {
+		msg += fmt.Sprintf(" :: %s :: %s", p.Method, p.URL)
+	}
+	msg += fmt.Sprintf(" :: %s :: %s", p.Type, p.Detail)
+
+	for _, sub := range p.SubProblems {
+		msg += fmt.Sprintf(", problem: %q :: %s", sub.Type, sub.Detail)
+	}
+
+	if p.Instance != "" {
+		msg += ", url: " + p.Instance
+	}
+
+	return msg
+}
+
+// NonceError represents the error which is returned
+// if the nonce sent by the client was not accepted by the server.
+type NonceError struct {
+	*ProblemDetails
+}

buildx.Dockerfile

@@ -0,0 +1,10 @@
+# syntax=docker/dockerfile:1.4
+FROM alpine:3
+
+RUN apk --no-cache --no-progress add git ca-certificates tzdata \
+    && rm -rf /var/cache/apk/*
+
+COPY lego /
+
+ENTRYPOINT ["/lego"]
+EXPOSE 80

certcrypto/crypto.go

@@ -0,0 +1,320 @@
+package certcrypto
+
+import (
+	"crypto"
+	"crypto/ecdsa"
+	"crypto/ed25519"
+	"crypto/elliptic"
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/x509"
+	"crypto/x509/pkix"
+	"encoding/asn1"
+	"encoding/pem"
+	"errors"
+	"fmt"
+	"math/big"
+	"net"
+	"strings"
+	"time"
+
+	"golang.org/x/crypto/ocsp"
+)
+
+// Constants for all key types we support.
+const (
+	EC256   = KeyType("P256")
+	EC384   = KeyType("P384")
+	RSA2048 = KeyType("2048")
+	RSA3072 = KeyType("3072")
+	RSA4096 = KeyType("4096")
+	RSA8192 = KeyType("8192")
+)
+
+const (
+	// OCSPGood means that the certificate is valid.
+	OCSPGood = ocsp.Good
+	// OCSPRevoked means that the certificate has been deliberately revoked.
+	OCSPRevoked = ocsp.Revoked
+	// OCSPUnknown means that the OCSP responder doesn't know about the certificate.
+	OCSPUnknown = ocsp.Unknown
+	// OCSPServerFailed means that the OCSP responder failed to process the request.
+	OCSPServerFailed = ocsp.ServerFailed
+)
+
+// Constants for OCSP must staple.
+var (
+	tlsFeatureExtensionOID = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 1, 24}
+	ocspMustStapleFeature  = []byte{0x30, 0x03, 0x02, 0x01, 0x05}
+)
+
+// KeyType represents the key algo as well as the key size or curve to use.
+type KeyType string
+
+type DERCertificateBytes []byte
+
+// ParsePEMBundle parses a certificate bundle from top to bottom and returns
+// a slice of x509 certificates. This function will error if no certificates are found.
+func ParsePEMBundle(bundle []byte) ([]*x509.Certificate, error) {
+	var certificates []*x509.Certificate
+	var certDERBlock *pem.Block
+
+	for {
+		certDERBlock, bundle = pem.Decode(bundle)
+		if certDERBlock == nil {
+			break
+		}
+
+		if certDERBlock.Type == "CERTIFICATE" {
+			cert, err := x509.ParseCertificate(certDERBlock.Bytes)
+			if err != nil {
+				return nil, err
+			}
+			certificates = append(certificates, cert)
+		}
+	}
+
+	if len(certificates) == 0 {
+		return nil, errors.New("no certificates were found while parsing the bundle")
+	}
+
+	return certificates, nil
+}
+
+// ParsePEMPrivateKey parses a private key from key, which is a PEM block.
+// Borrowed from Go standard library, to handle various private key and PEM block types.
+// https://github.com/golang/go/blob/693748e9fa385f1e2c3b91ca9acbb6c0ad2d133d/src/crypto/tls/tls.go#L291-L308
+// https://github.com/golang/go/blob/693748e9fa385f1e2c3b91ca9acbb6c0ad2d133d/src/crypto/tls/tls.go#L238)
+func ParsePEMPrivateKey(key []byte) (crypto.PrivateKey, error) {
+	keyBlockDER, _ := pem.Decode(key)
+	if keyBlockDER == nil {
+		return nil, fmt.Errorf("invalid PEM block")
+	}
+
+	if keyBlockDER.Type != "PRIVATE KEY" && !strings.HasSuffix(keyBlockDER.Type, " PRIVATE KEY") {
+		return nil, fmt.Errorf("unknown PEM header %q", keyBlockDER.Type)
+	}
+
+	if key, err := x509.ParsePKCS1PrivateKey(keyBlockDER.Bytes); err == nil {
+		return key, nil
+	}
+
+	if key, err := x509.ParsePKCS8PrivateKey(keyBlockDER.Bytes); err == nil {
+		switch key := key.(type) {
+		case *rsa.PrivateKey, *ecdsa.PrivateKey, ed25519.PrivateKey:
+			return key, nil
+		default:
+			return nil, fmt.Errorf("found unknown private key type in PKCS#8 wrapping: %T", key)
+		}
+	}
+
+	if key, err := x509.ParseECPrivateKey(keyBlockDER.Bytes); err == nil {
+		return key, nil
+	}
+
+	return nil, errors.New("failed to parse private key")
+}
+
+func GeneratePrivateKey(keyType KeyType) (crypto.PrivateKey, error) {
+	switch keyType {
+	case EC256:
+		return ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
+	case EC384:
+		return ecdsa.GenerateKey(elliptic.P384(), rand.Reader)
+	case RSA2048:
+		return rsa.GenerateKey(rand.Reader, 2048)
+	case RSA3072:
+		return rsa.GenerateKey(rand.Reader, 3072)
+	case RSA4096:
+		return rsa.GenerateKey(rand.Reader, 4096)
+	case RSA8192:
+		return rsa.GenerateKey(rand.Reader, 8192)
+	}
+
+	return nil, fmt.Errorf("invalid KeyType: %s", keyType)
+}
+
+func GenerateCSR(privateKey crypto.PrivateKey, domain string, san []string, mustStaple bool) ([]byte, error) {
+	var dnsNames []string
+	var ipAddresses []net.IP
+	for _, altname := range san {
+		if ip := net.ParseIP(altname); ip != nil {
+			ipAddresses = append(ipAddresses, ip)
+		} else {
+			dnsNames = append(dnsNames, altname)
+		}
+	}
+
+	template := x509.CertificateRequest{
+		Subject:     pkix.Name{CommonName: domain},
+		DNSNames:    dnsNames,
+		IPAddresses: ipAddresses,
+	}
+
+	if mustStaple {
+		template.ExtraExtensions = append(template.ExtraExtensions, pkix.Extension{
+			Id:    tlsFeatureExtensionOID,
+			Value: ocspMustStapleFeature,
+		})
+	}
+
+	return x509.CreateCertificateRequest(rand.Reader, &template, privateKey)
+}
+
+func PEMEncode(data interface{}) []byte {
+	return pem.EncodeToMemory(PEMBlock(data))
+}
+
+func PEMBlock(data interface{}) *pem.Block {
+	var pemBlock *pem.Block
+	switch key := data.(type) {
+	case *ecdsa.PrivateKey:
+		keyBytes, _ := x509.MarshalECPrivateKey(key)
+		pemBlock = &pem.Block{Type: "EC PRIVATE KEY", Bytes: keyBytes}
+	case *rsa.PrivateKey:
+		pemBlock = &pem.Block{Type: "RSA PRIVATE KEY", Bytes: x509.MarshalPKCS1PrivateKey(key)}
+	case *x509.CertificateRequest:
+		pemBlock = &pem.Block{Type: "CERTIFICATE REQUEST", Bytes: key.Raw}
+	case DERCertificateBytes:
+		pemBlock = &pem.Block{Type: "CERTIFICATE", Bytes: []byte(data.(DERCertificateBytes))}
+	}
+
+	return pemBlock
+}
+
+func pemDecode(data []byte) (*pem.Block, error) {
+	pemBlock, _ := pem.Decode(data)
+	if pemBlock == nil {
+		return nil, errors.New("PEM decode did not yield a valid block. Is the certificate in the right format?")
+	}
+
+	return pemBlock, nil
+}
+
+func PemDecodeTox509CSR(data []byte) (*x509.CertificateRequest, error) {
+	pemBlock, err := pemDecode(data)
+	if pemBlock == nil {
+		return nil, err
+	}
+
+	if pemBlock.Type != "CERTIFICATE REQUEST" && pemBlock.Type != "NEW CERTIFICATE REQUEST" {
+		return nil, errors.New("PEM block is not a certificate request")
+	}
+
+	return x509.ParseCertificateRequest(pemBlock.Bytes)
+}
+
+// ParsePEMCertificate returns Certificate from a PEM encoded certificate.
+// The certificate has to be PEM encoded. Any other encodings like DER will fail.
+func ParsePEMCertificate(cert []byte) (*x509.Certificate, error) {
+	pemBlock, err := pemDecode(cert)
+	if pemBlock == nil {
+		return nil, err
+	}
+
+	// from a DER encoded certificate
+	return x509.ParseCertificate(pemBlock.Bytes)
+}
+
+func ExtractDomains(cert *x509.Certificate) []string {
+	var domains []string
+	if cert.Subject.CommonName != "" {
+		domains = append(domains, cert.Subject.CommonName)
+	}
+
+	// Check for SAN certificate
+	for _, sanDomain := range cert.DNSNames {
+		if sanDomain == cert.Subject.CommonName {
+			continue
+		}
+		domains = append(domains, sanDomain)
+	}
+
+	commonNameIP := net.ParseIP(cert.Subject.CommonName)
+	for _, sanIP := range cert.IPAddresses {
+		if !commonNameIP.Equal(sanIP) {
+			domains = append(domains, sanIP.String())
+		}
+	}
+
+	return domains
+}
+
+func ExtractDomainsCSR(csr *x509.CertificateRequest) []string {
+	var domains []string
+	if csr.Subject.CommonName != "" {
+		domains = append(domains, csr.Subject.CommonName)
+	}
+
+	// loop over the SubjectAltName DNS names
+	for _, sanName := range csr.DNSNames {
+		if containsSAN(domains, sanName) {
+			// Duplicate; skip this name
+			continue
+		}
+
+		// Name is unique
+		domains = append(domains, sanName)
+	}
+
+	cnip := net.ParseIP(csr.Subject.CommonName)
+	for _, sanIP := range csr.IPAddresses {
+		if !cnip.Equal(sanIP) {
+			domains = append(domains, sanIP.String())
+		}
+	}
+
+	return domains
+}
+
+func containsSAN(domains []string, sanName string) bool {
+	for _, existingName := range domains {
+		if existingName == sanName {
+			return true
+		}
+	}
+	return false
+}
+
+func GeneratePemCert(privateKey *rsa.PrivateKey, domain string, extensions []pkix.Extension) ([]byte, error) {
+	derBytes, err := generateDerCert(privateKey, time.Time{}, domain, extensions)
+	if err != nil {
+		return nil, err
+	}
+
+	return pem.EncodeToMemory(&pem.Block{Type: "CERTIFICATE", Bytes: derBytes}), nil
+}
+
+func generateDerCert(privateKey *rsa.PrivateKey, expiration time.Time, domain string, extensions []pkix.Extension) ([]byte, error) {
+	serialNumberLimit := new(big.Int).Lsh(big.NewInt(1), 128)
+	serialNumber, err := rand.Int(rand.Reader, serialNumberLimit)
+	if err != nil {
+		return nil, err
+	}
+
+	if expiration.IsZero() {
+		expiration = time.Now().AddDate(1, 0, 0)
+	}
+
+	template := x509.Certificate{
+		SerialNumber: serialNumber,
+		Subject: pkix.Name{
+			CommonName: "ACME Challenge TEMP",
+		},
+		NotBefore: time.Now(),
+		NotAfter:  expiration,
+
+		KeyUsage:              x509.KeyUsageKeyEncipherment,
+		BasicConstraintsValid: true,
+		ExtraExtensions:       extensions,
+	}
+
+	// handling SAN filling as type suspected
+	if ip := net.ParseIP(domain); ip != nil {
+		template.IPAddresses = []net.IP{ip}
+	} else {
+		template.DNSNames = []string{domain}
+	}
+
+	return x509.CreateCertificate(rand.Reader, &template, &template, &privateKey.PublicKey, privateKey)
+}

certcrypto/crypto_test.go

@@ -0,0 +1,177 @@
+package certcrypto
+
+import (
+	"bytes"
+	"crypto"
+	"crypto/rand"
+	"crypto/rsa"
+	"encoding/pem"
+	"regexp"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestGeneratePrivateKey(t *testing.T) {
+	key, err := GeneratePrivateKey(RSA2048)
+	require.NoError(t, err, "Error generating private key")
+
+	assert.NotNil(t, key)
+}
+
+func TestGenerateCSR(t *testing.T) {
+	privateKey, err := rsa.GenerateKey(rand.Reader, 512)
+	require.NoError(t, err, "Error generating private key")
+
+	type expected struct {
+		len   int
+		error bool
+	}
+
+	testCases := []struct {
+		desc       string
+		privateKey crypto.PrivateKey
+		domain     string
+		san        []string
+		mustStaple bool
+		expected   expected
+	}{
+		{
+			desc:       "without SAN",
+			privateKey: privateKey,
+			domain:     "lego.acme",
+			mustStaple: true,
+			expected:   expected{len: 245},
+		},
+		{
+			desc:       "without SAN",
+			privateKey: privateKey,
+			domain:     "lego.acme",
+			san:        []string{},
+			mustStaple: true,
+			expected:   expected{len: 245},
+		},
+		{
+			desc:       "with SAN",
+			privateKey: privateKey,
+			domain:     "lego.acme",
+			san:        []string{"a.lego.acme", "b.lego.acme", "c.lego.acme"},
+			mustStaple: true,
+			expected:   expected{len: 296},
+		},
+		{
+			desc:       "no domain",
+			privateKey: privateKey,
+			domain:     "",
+			mustStaple: true,
+			expected:   expected{len: 225},
+		},
+		{
+			desc:       "no domain with SAN",
+			privateKey: privateKey,
+			domain:     "",
+			san:        []string{"a.lego.acme", "b.lego.acme", "c.lego.acme"},
+			mustStaple: true,
+			expected:   expected{len: 276},
+		},
+		{
+			desc:       "private key nil",
+			privateKey: nil,
+			domain:     "fizz.buzz",
+			mustStaple: true,
+			expected:   expected{error: true},
+		},
+	}
+
+	for _, test := range testCases {
+		test := test
+		t.Run(test.desc, func(t *testing.T) {
+			t.Parallel()
+
+			csr, err := GenerateCSR(test.privateKey, test.domain, test.san, test.mustStaple)
+
+			if test.expected.error {
+				require.Error(t, err)
+			} else {
+				require.NoError(t, err, "Error generating CSR")
+
+				assert.NotEmpty(t, csr)
+				assert.Len(t, csr, test.expected.len)
+			}
+		})
+	}
+}
+
+func TestPEMEncode(t *testing.T) {
+	buf := bytes.NewBufferString("TestingRSAIsSoMuchFun")
+
+	reader := MockRandReader{b: buf}
+	key, err := rsa.GenerateKey(reader, 32)
+	require.NoError(t, err, "Error generating private key")
+
+	data := PEMEncode(key)
+	require.NotNil(t, data)
+
+	exp := regexp.MustCompile(`^-----BEGIN RSA PRIVATE KEY-----\s+\S{60,}\s+-----END RSA PRIVATE KEY-----\s+`)
+	assert.Regexp(t, exp, string(data))
+}
+
+func TestParsePEMCertificate(t *testing.T) {
+	privateKey, err := GeneratePrivateKey(RSA2048)
+	require.NoError(t, err, "Error generating private key")
+
+	expiration := time.Now().Add(365).Round(time.Second)
+	certBytes, err := generateDerCert(privateKey.(*rsa.PrivateKey), expiration, "test.com", nil)
+	require.NoError(t, err, "Error generating cert")
+
+	buf := bytes.NewBufferString("TestingRSAIsSoMuchFun")
+
+	// Some random string should return an error.
+	cert, err := ParsePEMCertificate(buf.Bytes())
+	require.Errorf(t, err, "returned %v", cert)
+
+	// A DER encoded certificate should return an error.
+	_, err = ParsePEMCertificate(certBytes)
+	require.Error(t, err, "Expected to return an error for DER certificates")
+
+	// A PEM encoded certificate should work ok.
+	pemCert := PEMEncode(DERCertificateBytes(certBytes))
+	cert, err = ParsePEMCertificate(pemCert)
+	require.NoError(t, err)
+
+	assert.Equal(t, expiration.UTC(), cert.NotAfter)
+}
+
+func TestParsePEMPrivateKey(t *testing.T) {
+	privateKey, err := GeneratePrivateKey(RSA2048)
+	require.NoError(t, err, "Error generating private key")
+
+	pemPrivateKey := PEMEncode(privateKey)
+
+	// Decoding a key should work and create an identical key to the original
+	decoded, err := ParsePEMPrivateKey(pemPrivateKey)
+	require.NoError(t, err)
+	assert.Equal(t, decoded, privateKey)
+
+	// Decoding a PEM block that doesn't contain a private key should error
+	_, err = ParsePEMPrivateKey(pem.EncodeToMemory(&pem.Block{Type: "CERTIFICATE"}))
+	require.Errorf(t, err, "Expected to return an error for non-private key input")
+
+	// Decoding a PEM block that doesn't actually contain a key should error
+	_, err = ParsePEMPrivateKey(pem.EncodeToMemory(&pem.Block{Type: "PRIVATE KEY"}))
+	require.Errorf(t, err, "Expected to return an error for empty input")
+
+	// Decoding non-PEM input should return an error
+	_, err = ParsePEMPrivateKey([]byte("This is not PEM"))
+	require.Errorf(t, err, "Expected to return an error for non-PEM input")
+}
+
+type MockRandReader struct {
+	b *bytes.Buffer
+}
+
+func (r MockRandReader) Read(p []byte) (int, error) {
+	return r.b.Read(p)
+}

certificate/authorization.go

@@ -0,0 +1,81 @@
+package certificate
+
+import (
+	"time"
+
+	"github.com/go-acme/lego/v4/acme"
+	"github.com/go-acme/lego/v4/log"
+)
+
+const (
+	// overallRequestLimit is the overall number of request per second
+	// limited on the "new-reg", "new-authz" and "new-cert" endpoints.
+	// From the documentation the limitation is 20 requests per second,
+	// but using 20 as value doesn't work but 18 do.
+	overallRequestLimit = 18
+)
+
+func (c *Certifier) getAuthorizations(order acme.ExtendedOrder) ([]acme.Authorization, error) {
+	resc, errc := make(chan acme.Authorization), make(chan domainError)
+
+	delay := time.Second / overallRequestLimit
+
+	for _, authzURL := range order.Authorizations {
+		time.Sleep(delay)
+
+		go func(authzURL string) {
+			authz, err := c.core.Authorizations.Get(authzURL)
+			if err != nil {
+				errc <- domainError{Domain: authz.Identifier.Value, Error: err}
+				return
+			}
+
+			resc <- authz
+		}(authzURL)
+	}
+
+	var responses []acme.Authorization
+	failures := make(obtainError)
+	for i := 0; i < len(order.Authorizations); i++ {
+		select {
+		case res := <-resc:
+			responses = append(responses, res)
+		case err := <-errc:
+			failures[err.Domain] = err.Error
+		}
+	}
+
+	for i, auth := range order.Authorizations {
+		log.Infof("[%s] AuthURL: %s", order.Identifiers[i].Value, auth)
+	}
+
+	close(resc)
+	close(errc)
+
+	// be careful to not return an empty failures map;
+	// even if empty, they become non-nil error values
+	if len(failures) > 0 {
+		return responses, failures
+	}
+	return responses, nil
+}
+
+func (c *Certifier) deactivateAuthorizations(order acme.ExtendedOrder, force bool) {
+	for _, authzURL := range order.Authorizations {
+		auth, err := c.core.Authorizations.Get(authzURL)
+		if err != nil {
+			log.Infof("Unable to get the authorization for: %s", authzURL)
+			continue
+		}
+
+		if auth.Status == acme.StatusValid && !force {
+			log.Infof("Skipping deactivating of valid auth: %s", authzURL)
+			continue
+		}
+
+		log.Infof("Deactivating auth: %s", authzURL)
+		if c.core.Authorizations.Deactivate(authzURL) != nil {
+			log.Infof("Unable to deactivate the authorization: %s", authzURL)
+		}
+	}
+}

certificate/certificates.go

@@ -0,0 +1,662 @@
+package certificate
+
+import (
+	"bytes"
+	"crypto"
+	"crypto/x509"
+	"encoding/base64"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"strings"
+	"time"
+
+	"github.com/go-acme/lego/v4/acme"
+	"github.com/go-acme/lego/v4/acme/api"
+	"github.com/go-acme/lego/v4/certcrypto"
+	"github.com/go-acme/lego/v4/challenge"
+	"github.com/go-acme/lego/v4/log"
+	"github.com/go-acme/lego/v4/platform/wait"
+	"golang.org/x/crypto/ocsp"
+	"golang.org/x/net/idna"
+)
+
+// maxBodySize is the maximum size of body that we will read.
+const maxBodySize = 1024 * 1024
+
+// Resource represents a CA issued certificate.
+// PrivateKey, Certificate and IssuerCertificate are all
+// already PEM encoded and can be directly written to disk.
+// Certificate may be a certificate bundle,
+// depending on the options supplied to create it.
+type Resource struct {
+	Domain            string `json:"domain"`
+	CertURL           string `json:"certUrl"`
+	CertStableURL     string `json:"certStableUrl"`
+	PrivateKey        []byte `json:"-"`
+	Certificate       []byte `json:"-"`
+	IssuerCertificate []byte `json:"-"`
+	CSR               []byte `json:"-"`
+}
+
+// ObtainRequest The request to obtain certificate.
+//
+// The first domain in domains is used for the CommonName field of the certificate,
+// all other domains are added using the Subject Alternate Names extension.
+//
+// A new private key is generated for every invocation of the function Obtain.
+// If you do not want that you can supply your own private key in the privateKey parameter.
+// If this parameter is non-nil it will be used instead of generating a new one.
+//
+// If `Bundle` is true, the `[]byte` contains both the issuer certificate and your issued certificate as a bundle.
+//
+// If `AlwaysDeactivateAuthorizations` is true, the authorizations are also relinquished if the obtain request was successful.
+// See https://datatracker.ietf.org/doc/html/rfc8555#section-7.5.2.
+type ObtainRequest struct {
+	Domains    []string
+	PrivateKey crypto.PrivateKey
+	MustStaple bool
+
+	NotBefore                      time.Time
+	NotAfter                       time.Time
+	Bundle                         bool
+	PreferredChain                 string
+	AlwaysDeactivateAuthorizations bool
+}
+
+// ObtainForCSRRequest The request to obtain a certificate matching the CSR passed into it.
+//
+// If `Bundle` is true, the `[]byte` contains both the issuer certificate and your issued certificate as a bundle.
+//
+// If `AlwaysDeactivateAuthorizations` is true, the authorizations are also relinquished if the obtain request was successful.
+// See https://datatracker.ietf.org/doc/html/rfc8555#section-7.5.2.
+type ObtainForCSRRequest struct {
+	CSR *x509.CertificateRequest
+
+	NotBefore                      time.Time
+	NotAfter                       time.Time
+	Bundle                         bool
+	PreferredChain                 string
+	AlwaysDeactivateAuthorizations bool
+}
+
+type resolver interface {
+	Solve(authorizations []acme.Authorization) error
+}
+
+type CertifierOptions struct {
+	KeyType certcrypto.KeyType
+	Timeout time.Duration
+}
+
+// Certifier A service to obtain/renew/revoke certificates.
+type Certifier struct {
+	core     *api.Core
+	resolver resolver
+	options  CertifierOptions
+}
+
+// NewCertifier creates a Certifier.
+func NewCertifier(core *api.Core, resolver resolver, options CertifierOptions) *Certifier {
+	return &Certifier{
+		core:     core,
+		resolver: resolver,
+		options:  options,
+	}
+}
+
+// Obtain tries to obtain a single certificate using all domains passed into it.
+//
+// This function will never return a partial certificate.
+// If one domain in the list fails, the whole certificate will fail.
+func (c *Certifier) Obtain(request ObtainRequest) (*Resource, error) {
+	if len(request.Domains) == 0 {
+		return nil, errors.New("no domains to obtain a certificate for")
+	}
+
+	domains := sanitizeDomain(request.Domains)
+
+	if request.Bundle {
+		log.Infof("[%s] acme: Obtaining bundled SAN certificate", strings.Join(domains, ", "))
+	} else {
+		log.Infof("[%s] acme: Obtaining SAN certificate", strings.Join(domains, ", "))
+	}
+
+	orderOpts := &api.OrderOptions{
+		NotBefore: request.NotBefore,
+		NotAfter:  request.NotAfter,
+	}
+
+	order, err := c.core.Orders.NewWithOptions(domains, orderOpts)
+	if err != nil {
+		return nil, err
+	}
+
+	authz, err := c.getAuthorizations(order)
+	if err != nil {
+		// If any challenge fails, return. Do not generate partial SAN certificates.
+		c.deactivateAuthorizations(order, request.AlwaysDeactivateAuthorizations)
+		return nil, err
+	}
+
+	err = c.resolver.Solve(authz)
+	if err != nil {
+		// If any challenge fails, return. Do not generate partial SAN certificates.
+		c.deactivateAuthorizations(order, request.AlwaysDeactivateAuthorizations)
+		return nil, err
+	}
+
+	log.Infof("[%s] acme: Validations succeeded; requesting certificates", strings.Join(domains, ", "))
+
+	failures := make(obtainError)
+	cert, err := c.getForOrder(domains, order, request.Bundle, request.PrivateKey, request.MustStaple, request.PreferredChain)
+	if err != nil {
+		for _, auth := range authz {
+			failures[challenge.GetTargetedDomain(auth)] = err
+		}
+	}
+
+	if request.AlwaysDeactivateAuthorizations {
+		c.deactivateAuthorizations(order, true)
+	}
+
+	// Do not return an empty failures map, because
+	// it would still be a non-nil error value
+	if len(failures) > 0 {
+		return cert, failures
+	}
+	return cert, nil
+}
+
+// ObtainForCSR tries to obtain a certificate matching the CSR passed into it.
+//
+// The domains are inferred from the CommonName and SubjectAltNames, if any.
+// The private key for this CSR is not required.
+//
+// If bundle is true, the []byte contains both the issuer certificate and your issued certificate as a bundle.
+//
+// This function will never return a partial certificate.
+// If one domain in the list fails, the whole certificate will fail.
+func (c *Certifier) ObtainForCSR(request ObtainForCSRRequest) (*Resource, error) {
+	if request.CSR == nil {
+		return nil, errors.New("cannot obtain resource for CSR: CSR is missing")
+	}
+
+	// figure out what domains it concerns
+	// start with the common name
+	domains := certcrypto.ExtractDomainsCSR(request.CSR)
+
+	if request.Bundle {
+		log.Infof("[%s] acme: Obtaining bundled SAN certificate given a CSR", strings.Join(domains, ", "))
+	} else {
+		log.Infof("[%s] acme: Obtaining SAN certificate given a CSR", strings.Join(domains, ", "))
+	}
+
+	orderOpts := &api.OrderOptions{
+		NotBefore: request.NotBefore,
+		NotAfter:  request.NotAfter,
+	}
+
+	order, err := c.core.Orders.NewWithOptions(domains, orderOpts)
+	if err != nil {
+		return nil, err
+	}
+
+	authz, err := c.getAuthorizations(order)
+	if err != nil {
+		// If any challenge fails, return. Do not generate partial SAN certificates.
+		c.deactivateAuthorizations(order, request.AlwaysDeactivateAuthorizations)
+		return nil, err
+	}
+
+	err = c.resolver.Solve(authz)
+	if err != nil {
+		// If any challenge fails, return. Do not generate partial SAN certificates.
+		c.deactivateAuthorizations(order, request.AlwaysDeactivateAuthorizations)
+		return nil, err
+	}
+
+	log.Infof("[%s] acme: Validations succeeded; requesting certificates", strings.Join(domains, ", "))
+
+	failures := make(obtainError)
+	cert, err := c.getForCSR(domains, order, request.Bundle, request.CSR.Raw, nil, request.PreferredChain)
+	if err != nil {
+		for _, auth := range authz {
+			failures[challenge.GetTargetedDomain(auth)] = err
+		}
+	}
+
+	if request.AlwaysDeactivateAuthorizations {
+		c.deactivateAuthorizations(order, true)
+	}
+
+	if cert != nil {
+		// Add the CSR to the certificate so that it can be used for renewals.
+		cert.CSR = certcrypto.PEMEncode(request.CSR)
+	}
+
+	// Do not return an empty failures map,
+	// because it would still be a non-nil error value
+	if len(failures) > 0 {
+		return cert, failures
+	}
+	return cert, nil
+}
+
+func (c *Certifier) getForOrder(domains []string, order acme.ExtendedOrder, bundle bool, privateKey crypto.PrivateKey, mustStaple bool, preferredChain string) (*Resource, error) {
+	if privateKey == nil {
+		var err error
+		privateKey, err = certcrypto.GeneratePrivateKey(c.options.KeyType)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	// Determine certificate name(s) based on the authorization resources
+	commonName := domains[0]
+
+	// RFC8555 Section 7.4 "Applying for Certificate Issuance"
+	// https://www.rfc-editor.org/rfc/rfc8555.html#section-7.4
+	// says:
+	//   Clients SHOULD NOT make any assumptions about the sort order of
+	//   "identifiers" or "authorizations" elements in the returned order
+	//   object.
+	san := []string{commonName}
+	for _, auth := range order.Identifiers {
+		if auth.Value != commonName {
+			san = append(san, auth.Value)
+		}
+	}
+
+	// TODO: should the CSR be customizable?
+	csr, err := certcrypto.GenerateCSR(privateKey, commonName, san, mustStaple)
+	if err != nil {
+		return nil, err
+	}
+
+	return c.getForCSR(domains, order, bundle, csr, certcrypto.PEMEncode(privateKey), preferredChain)
+}
+
+func (c *Certifier) getForCSR(domains []string, order acme.ExtendedOrder, bundle bool, csr, privateKeyPem []byte, preferredChain string) (*Resource, error) {
+	respOrder, err := c.core.Orders.UpdateForCSR(order.Finalize, csr)
+	if err != nil {
+		return nil, err
+	}
+
+	commonName := domains[0]
+	certRes := &Resource{
+		Domain:     commonName,
+		CertURL:    respOrder.Certificate,
+		PrivateKey: privateKeyPem,
+	}
+
+	if respOrder.Status == acme.StatusValid {
+		// if the certificate is available right away, short cut!
+		ok, errR := c.checkResponse(respOrder, certRes, bundle, preferredChain)
+		if errR != nil {
+			return nil, errR
+		}
+
+		if ok {
+			return certRes, nil
+		}
+	}
+
+	timeout := c.options.Timeout
+	if c.options.Timeout <= 0 {
+		timeout = 30 * time.Second
+	}
+
+	err = wait.For("certificate", timeout, timeout/60, func() (bool, error) {
+		ord, errW := c.core.Orders.Get(order.Location)
+		if errW != nil {
+			return false, errW
+		}
+
+		done, errW := c.checkResponse(ord, certRes, bundle, preferredChain)
+		if errW != nil {
+			return false, errW
+		}
+
+		return done, nil
+	})
+
+	return certRes, err
+}
+
+// checkResponse checks to see if the certificate is ready and a link is contained in the response.
+//
+// If so, loads it into certRes and returns true.
+// If the cert is not yet ready, it returns false.
+//
+// The certRes input should already have the Domain (common name) field populated.
+//
+// If bundle is true, the certificate will be bundled with the issuer's cert.
+func (c *Certifier) checkResponse(order acme.ExtendedOrder, certRes *Resource, bundle bool, preferredChain string) (bool, error) {
+	valid, err := checkOrderStatus(order)
+	if err != nil || !valid {
+		return valid, err
+	}
+
+	certs, err := c.core.Certificates.GetAll(order.Certificate, bundle)
+	if err != nil {
+		return false, err
+	}
+
+	// Set the default certificate
+	certRes.IssuerCertificate = certs[order.Certificate].Issuer
+	certRes.Certificate = certs[order.Certificate].Cert
+	certRes.CertURL = order.Certificate
+	certRes.CertStableURL = order.Certificate
+
+	if preferredChain == "" {
+		log.Infof("[%s] Server responded with a certificate.", certRes.Domain)
+
+		return true, nil
+	}
+
+	for link, cert := range certs {
+		ok, err := hasPreferredChain(cert.Issuer, preferredChain)
+		if err != nil {
+			return false, err
+		}
+
+		if ok {
+			log.Infof("[%s] Server responded with a certificate for the preferred certificate chains %q.", certRes.Domain, preferredChain)
+
+			certRes.IssuerCertificate = cert.Issuer
+			certRes.Certificate = cert.Cert
+			certRes.CertURL = link
+			certRes.CertStableURL = link
+
+			return true, nil
+		}
+	}
+
+	log.Infof("lego has been configured to prefer certificate chains with issuer %q, but no chain from the CA matched this issuer. Using the default certificate chain instead.", preferredChain)
+
+	return true, nil
+}
+
+// Revoke takes a PEM encoded certificate or bundle and tries to revoke it at the CA.
+func (c *Certifier) Revoke(cert []byte) error {
+	return c.RevokeWithReason(cert, nil)
+}
+
+// RevokeWithReason takes a PEM encoded certificate or bundle and tries to revoke it at the CA.
+func (c *Certifier) RevokeWithReason(cert []byte, reason *uint) error {
+	certificates, err := certcrypto.ParsePEMBundle(cert)
+	if err != nil {
+		return err
+	}
+
+	x509Cert := certificates[0]
+	if x509Cert.IsCA {
+		return errors.New("certificate bundle starts with a CA certificate")
+	}
+
+	revokeMsg := acme.RevokeCertMessage{
+		Certificate: base64.RawURLEncoding.EncodeToString(x509Cert.Raw),
+		Reason:      reason,
+	}
+
+	return c.core.Certificates.Revoke(revokeMsg)
+}
+
+// RenewOptions options used by Certifier.RenewWithOptions.
+type RenewOptions struct {
+	NotBefore time.Time
+	NotAfter  time.Time
+	// If true, the []byte contains both the issuer certificate and your issued certificate as a bundle.
+	Bundle                         bool
+	PreferredChain                 string
+	AlwaysDeactivateAuthorizations bool
+	// Not supported for CSR request.
+	MustStaple bool
+}
+
+// Renew takes a Resource and tries to renew the certificate.
+//
+// If the renewal process succeeds, the new certificate will be returned in a new CertResource.
+// Please be aware that this function will return a new certificate in ANY case that is not an error.
+// If the server does not provide us with a new cert on a GET request to the CertURL
+// this function will start a new-cert flow where a new certificate gets generated.
+//
+// If bundle is true, the []byte contains both the issuer certificate and your issued certificate as a bundle.
+//
+// For private key reuse the PrivateKey property of the passed in Resource should be non-nil.
+// Deprecated: use RenewWithOptions instead.
+func (c *Certifier) Renew(certRes Resource, bundle, mustStaple bool, preferredChain string) (*Resource, error) {
+	return c.RenewWithOptions(certRes, &RenewOptions{
+		Bundle:         bundle,
+		PreferredChain: preferredChain,
+		MustStaple:     mustStaple,
+	})
+}
+
+// RenewWithOptions takes a Resource and tries to renew the certificate.
+//
+// If the renewal process succeeds, the new certificate will be returned in a new CertResource.
+// Please be aware that this function will return a new certificate in ANY case that is not an error.
+// If the server does not provide us with a new cert on a GET request to the CertURL
+// this function will start a new-cert flow where a new certificate gets generated.
+//
+// If bundle is true, the []byte contains both the issuer certificate and your issued certificate as a bundle.
+//
+// For private key reuse the PrivateKey property of the passed in Resource should be non-nil.
+func (c *Certifier) RenewWithOptions(certRes Resource, options *RenewOptions) (*Resource, error) {
+	// Input certificate is PEM encoded.
+	// Decode it here as we may need the decoded cert later on in the renewal process.
+	// The input may be a bundle or a single certificate.
+	certificates, err := certcrypto.ParsePEMBundle(certRes.Certificate)
+	if err != nil {
+		return nil, err
+	}
+
+	x509Cert := certificates[0]
+	if x509Cert.IsCA {
+		return nil, fmt.Errorf("[%s] Certificate bundle starts with a CA certificate", certRes.Domain)
+	}
+
+	// This is just meant to be informal for the user.
+	timeLeft := x509Cert.NotAfter.Sub(time.Now().UTC())
+	log.Infof("[%s] acme: Trying renewal with %d hours remaining", certRes.Domain, int(timeLeft.Hours()))
+
+	// We always need to request a new certificate to renew.
+	// Start by checking to see if the certificate was based off a CSR,
+	// and use that if it's defined.
+	if len(certRes.CSR) > 0 {
+		csr, errP := certcrypto.PemDecodeTox509CSR(certRes.CSR)
+		if errP != nil {
+			return nil, errP
+		}
+
+		request := ObtainForCSRRequest{CSR: csr}
+
+		if options != nil {
+			request.NotBefore = options.NotBefore
+			request.NotAfter = options.NotAfter
+			request.Bundle = options.Bundle
+			request.PreferredChain = options.PreferredChain
+			request.AlwaysDeactivateAuthorizations = options.AlwaysDeactivateAuthorizations
+		}
+
+		return c.ObtainForCSR(request)
+	}
+
+	var privateKey crypto.PrivateKey
+	if certRes.PrivateKey != nil {
+		privateKey, err = certcrypto.ParsePEMPrivateKey(certRes.PrivateKey)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	request := ObtainRequest{
+		Domains:    certcrypto.ExtractDomains(x509Cert),
+		PrivateKey: privateKey,
+	}
+
+	if options != nil {
+		request.MustStaple = options.MustStaple
+		request.NotBefore = options.NotBefore
+		request.NotAfter = options.NotAfter
+		request.Bundle = options.Bundle
+		request.PreferredChain = options.PreferredChain
+		request.AlwaysDeactivateAuthorizations = options.AlwaysDeactivateAuthorizations
+	}
+
+	return c.Obtain(request)
+}
+
+// GetOCSP takes a PEM encoded cert or cert bundle returning the raw OCSP response,
+// the parsed response, and an error, if any.
+//
+// The returned []byte can be passed directly into the OCSPStaple property of a tls.Certificate.
+// If the bundle only contains the issued certificate,
+// this function will try to get the issuer certificate from the IssuingCertificateURL in the certificate.
+//
+// If the []byte and/or ocsp.Response return values are nil, the OCSP status may be assumed OCSPUnknown.
+func (c *Certifier) GetOCSP(bundle []byte) ([]byte, *ocsp.Response, error) {
+	certificates, err := certcrypto.ParsePEMBundle(bundle)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	// We expect the certificate slice to be ordered downwards the chain.
+	// SRV CRT -> CA. We need to pull the leaf and issuer certs out of it,
+	// which should always be the first two certificates.
+	// If there's no OCSP server listed in the leaf cert, there's nothing to do.
+	// And if we have only one certificate so far, we need to get the issuer cert.
+
+	issuedCert := certificates[0]
+
+	if len(issuedCert.OCSPServer) == 0 {
+		return nil, nil, errors.New("no OCSP server specified in cert")
+	}
+
+	if len(certificates) == 1 {
+		// TODO: build fallback. If this fails, check the remaining array entries.
+		if len(issuedCert.IssuingCertificateURL) == 0 {
+			return nil, nil, errors.New("no issuing certificate URL")
+		}
+
+		resp, errC := c.core.HTTPClient.Get(issuedCert.IssuingCertificateURL[0])
+		if errC != nil {
+			return nil, nil, errC
+		}
+		defer resp.Body.Close()
+
+		issuerBytes, errC := io.ReadAll(http.MaxBytesReader(nil, resp.Body, maxBodySize))
+		if errC != nil {
+			return nil, nil, errC
+		}
+
+		issuerCert, errC := x509.ParseCertificate(issuerBytes)
+		if errC != nil {
+			return nil, nil, errC
+		}
+
+		// Insert it into the slice on position 0
+		// We want it ordered right SRV CRT -> CA
+		certificates = append(certificates, issuerCert)
+	}
+
+	issuerCert := certificates[1]
+
+	// Finally kick off the OCSP request.
+	ocspReq, err := ocsp.CreateRequest(issuedCert, issuerCert, nil)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	resp, err := c.core.HTTPClient.Post(issuedCert.OCSPServer[0], "application/ocsp-request", bytes.NewReader(ocspReq))
+	if err != nil {
+		return nil, nil, err
+	}
+	defer resp.Body.Close()
+
+	ocspResBytes, err := io.ReadAll(http.MaxBytesReader(nil, resp.Body, maxBodySize))
+	if err != nil {
+		return nil, nil, err
+	}
+
+	ocspRes, err := ocsp.ParseResponse(ocspResBytes, issuerCert)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	return ocspResBytes, ocspRes, nil
+}
+
+// Get attempts to fetch the certificate at the supplied URL.
+// The URL is the same as what would normally be supplied at the Resource's CertURL.
+//
+// The returned Resource will not have the PrivateKey and CSR fields populated as these will not be available.
+//
+// If bundle is true, the Certificate field in the returned Resource includes the issuer certificate.
+func (c *Certifier) Get(url string, bundle bool) (*Resource, error) {
+	cert, issuer, err := c.core.Certificates.Get(url, bundle)
+	if err != nil {
+		return nil, err
+	}
+
+	// Parse the returned cert bundle so that we can grab the domain from the common name.
+	x509Certs, err := certcrypto.ParsePEMBundle(cert)
+	if err != nil {
+		return nil, err
+	}
+
+	return &Resource{
+		Domain:            x509Certs[0].Subject.CommonName,
+		Certificate:       cert,
+		IssuerCertificate: issuer,
+		CertURL:           url,
+		CertStableURL:     url,
+	}, nil
+}
+
+func hasPreferredChain(issuer []byte, preferredChain string) (bool, error) {
+	certs, err := certcrypto.ParsePEMBundle(issuer)
+	if err != nil {
+		return false, err
+	}
+
+	topCert := certs[len(certs)-1]
+
+	if topCert.Issuer.CommonName == preferredChain {
+		return true, nil
+	}
+
+	return false, nil
+}
+
+func checkOrderStatus(order acme.ExtendedOrder) (bool, error) {
+	switch order.Status {
+	case acme.StatusValid:
+		return true, nil
+	case acme.StatusInvalid:
+		return false, order.Error
+	default:
+		return false, nil
+	}
+}
+
+// https://www.rfc-editor.org/rfc/rfc8555.html#section-7.1.4
+// The domain name MUST be encoded in the form in which it would appear in a certificate.
+// That is, it MUST be encoded according to the rules in Section 7 of [RFC5280].
+//
+// https://www.rfc-editor.org/rfc/rfc5280.html#section-7
+func sanitizeDomain(domains []string) []string {
+	var sanitizedDomains []string
+	for _, domain := range domains {
+		sanitizedDomain, err := idna.ToASCII(domain)
+		if err != nil {
+			log.Infof("skip domain %q: unable to sanitize (punnycode): %v", domain, err)
+		} else {
+			sanitizedDomains = append(sanitizedDomains, sanitizedDomain)
+		}
+	}
+	return sanitizedDomains
+}

certificate/certificates_test.go

@@ -0,0 +1,398 @@
+package certificate
+
+import (
+	"crypto/rand"
+	"crypto/rsa"
+	"encoding/pem"
+	"fmt"
+	"net/http"
+	"testing"
+
+	"github.com/go-acme/lego/v4/acme"
+	"github.com/go-acme/lego/v4/acme/api"
+	"github.com/go-acme/lego/v4/certcrypto"
+	"github.com/go-acme/lego/v4/platform/tester"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+const certResponseNoBundleMock = `-----BEGIN CERTIFICATE-----
+MIIDEDCCAfigAwIBAgIHPhckqW5fPDANBgkqhkiG9w0BAQsFADAoMSYwJAYDVQQD
+Ex1QZWJibGUgSW50ZXJtZWRpYXRlIENBIDM5NWU2MTAeFw0xODExMDcxNzQ2NTZa
+Fw0yMzExMDcxNzQ2NTZaMBMxETAPBgNVBAMTCGFjbWUud3RmMIIBIjANBgkqhkiG
+9w0BAQEFAAOCAQ8AMIIBCgKCAQEAwtLNKvZXD20XPUQCWYSK9rUSKxD9Eb0c9fag
+bxOxOkLRTgL8LH6yln+bxc3MrHDou4PpDUdeo2CyOQu3CKsTS5mrH3NXYHu0H7p5
+y3riOJTHnfkGKLT9LciGz7GkXd62nvNP57bOf5Sk4P2M+Qbxd0hPTSfu52740LSy
+144cnxe2P1aDYehrEp6nYCESuyD/CtUHTo0qwJmzIy163Sp3rSs15BuCPyhySnE3
+BJ8Ggv+qC6D5I1932DfSqyQJ79iq/HRm0Fn84am3KwvRlUfWxabmsUGARXoqCgnE
+zcbJVOZKewv0zlQJpfac+b+Imj6Lvt1TGjIz2mVyefYgLx8gwwIDAQABo1QwUjAO
+BgNVHQ8BAf8EBAMCBaAwHQYDVR0lBBYwFAYIKwYBBQUHAwEGCCsGAQUFBwMCMAwG
+A1UdEwEB/wQCMAAwEwYDVR0RBAwwCoIIYWNtZS53dGYwDQYJKoZIhvcNAQELBQAD
+ggEBABB/0iYhmfPSQot5RaeeovQnsqYjI5ryQK2cwzW6qcTJfv8N6+p6XkqF1+W4
+jXZjrQP8MvgO9KNWlvx12vhINE6wubk88L+2piAi5uS2QejmZbXpyYB9s+oPqlk9
+IDvfdlVYOqvYAhSx7ggGi+j73mjZVtjAavP6dKuu475ZCeq+NIC15RpbbikWKtYE
+HBJ7BW8XQKx67iHGx8ygHTDLbREL80Bck3oUm7wIYGMoNijD6RBl25p4gYl9dzOd
+TqGl5hW/1P5hMbgEzHbr4O3BfWqU2g7tV36TASy3jbC3ONFRNNYrpEZ1AL3+cUri
+OPPkKtAKAbQkKbUIfsHpBZjKZMU=
+-----END CERTIFICATE-----
+`
+
+const certResponseMock = `-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----
+`
+
+const issuerMock = `-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----
+`
+
+const certResponseMock2 = `
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----
+`
+
+const issuerMock2 = `-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----
+`
+
+func Test_checkResponse(t *testing.T) {
+	mux, apiURL := tester.SetupFakeAPI(t)
+
+	mux.HandleFunc("/certificate", func(w http.ResponseWriter, _ *http.Request) {
+		_, err := w.Write([]byte(certResponseMock))
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+	})
+
+	key, err := rsa.GenerateKey(rand.Reader, 2048)
+	require.NoError(t, err, "Could not generate test key")
+
+	core, err := api.New(http.DefaultClient, "lego-test", apiURL+"/dir", "", key)
+	require.NoError(t, err)
+
+	certifier := NewCertifier(core, &resolverMock{}, CertifierOptions{KeyType: certcrypto.RSA2048})
+
+	order := acme.ExtendedOrder{
+		Order: acme.Order{
+			Status:      acme.StatusValid,
+			Certificate: apiURL + "/certificate",
+		},
+	}
+	certRes := &Resource{}
+
+	valid, err := certifier.checkResponse(order, certRes, true, "")
+	require.NoError(t, err)
+	assert.True(t, valid)
+	assert.NotNil(t, certRes)
+	assert.Equal(t, "", certRes.Domain)
+	assert.Contains(t, certRes.CertStableURL, "/certificate")
+	assert.Contains(t, certRes.CertURL, "/certificate")
+	assert.Nil(t, certRes.CSR)
+	assert.Nil(t, certRes.PrivateKey)
+	assert.Equal(t, certResponseMock, string(certRes.Certificate), "Certificate")
+	assert.Equal(t, issuerMock, string(certRes.IssuerCertificate), "IssuerCertificate")
+}
+
+func Test_checkResponse_issuerRelUp(t *testing.T) {
+	mux, apiURL := tester.SetupFakeAPI(t)
+
+	mux.HandleFunc("/certificate", func(w http.ResponseWriter, _ *http.Request) {
+		w.Header().Set("Link", "<"+apiURL+`/issuer>; rel="up"`)
+		_, err := w.Write([]byte(certResponseMock))
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+	})
+
+	mux.HandleFunc("/issuer", func(w http.ResponseWriter, _ *http.Request) {
+		p, _ := pem.Decode([]byte(issuerMock))
+		_, err := w.Write(p.Bytes)
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+	})
+
+	key, err := rsa.GenerateKey(rand.Reader, 2048)
+	require.NoError(t, err, "Could not generate test key")
+
+	core, err := api.New(http.DefaultClient, "lego-test", apiURL+"/dir", "", key)
+	require.NoError(t, err)
+
+	certifier := NewCertifier(core, &resolverMock{}, CertifierOptions{KeyType: certcrypto.RSA2048})
+
+	order := acme.ExtendedOrder{
+		Order: acme.Order{
+			Status:      acme.StatusValid,
+			Certificate: apiURL + "/certificate",
+		},
+	}
+	certRes := &Resource{}
+
+	valid, err := certifier.checkResponse(order, certRes, true, "")
+	require.NoError(t, err)
+	assert.True(t, valid)
+	assert.NotNil(t, certRes)
+	assert.Equal(t, "", certRes.Domain)
+	assert.Contains(t, certRes.CertStableURL, "/certificate")
+	assert.Contains(t, certRes.CertURL, "/certificate")
+	assert.Nil(t, certRes.CSR)
+	assert.Nil(t, certRes.PrivateKey)
+	assert.Equal(t, certResponseMock, string(certRes.Certificate), "Certificate")
+	assert.Equal(t, issuerMock, string(certRes.IssuerCertificate), "IssuerCertificate")
+}
+
+func Test_checkResponse_no_bundle(t *testing.T) {
+	mux, apiURL := tester.SetupFakeAPI(t)
+
+	mux.HandleFunc("/certificate", func(w http.ResponseWriter, _ *http.Request) {
+		_, err := w.Write([]byte(certResponseMock))
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+	})
+
+	key, err := rsa.GenerateKey(rand.Reader, 2048)
+	require.NoError(t, err, "Could not generate test key")
+
+	core, err := api.New(http.DefaultClient, "lego-test", apiURL+"/dir", "", key)
+	require.NoError(t, err)
+
+	certifier := NewCertifier(core, &resolverMock{}, CertifierOptions{KeyType: certcrypto.RSA2048})
+
+	order := acme.ExtendedOrder{
+		Order: acme.Order{
+			Status:      acme.StatusValid,
+			Certificate: apiURL + "/certificate",
+		},
+	}
+	certRes := &Resource{}
+
+	valid, err := certifier.checkResponse(order, certRes, false, "")
+	require.NoError(t, err)
+	assert.True(t, valid)
+	assert.NotNil(t, certRes)
+	assert.Equal(t, "", certRes.Domain)
+	assert.Contains(t, certRes.CertStableURL, "/certificate")
+	assert.Contains(t, certRes.CertURL, "/certificate")
+	assert.Nil(t, certRes.CSR)
+	assert.Nil(t, certRes.PrivateKey)
+	assert.Equal(t, certResponseNoBundleMock, string(certRes.Certificate), "Certificate")
+	assert.Equal(t, issuerMock, string(certRes.IssuerCertificate), "IssuerCertificate")
+}
+
+func Test_checkResponse_alternate(t *testing.T) {
+	mux, apiURL := tester.SetupFakeAPI(t)
+
+	mux.HandleFunc("/certificate", func(w http.ResponseWriter, _ *http.Request) {
+		w.Header().Add("Link", fmt.Sprintf(`<%s/certificate/1>;title="foo";rel="alternate"`, apiURL))
+
+		_, err := w.Write([]byte(certResponseMock))
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+	})
+
+	mux.HandleFunc("/certificate/1", func(w http.ResponseWriter, _ *http.Request) {
+		_, err := w.Write([]byte(certResponseMock2))
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+	})
+
+	key, err := rsa.GenerateKey(rand.Reader, 2048)
+	require.NoError(t, err, "Could not generate test key")
+
+	core, err := api.New(http.DefaultClient, "lego-test", apiURL+"/dir", "", key)
+	require.NoError(t, err)
+
+	certifier := NewCertifier(core, &resolverMock{}, CertifierOptions{KeyType: certcrypto.RSA2048})
+
+	order := acme.ExtendedOrder{
+		Order: acme.Order{
+			Status:      acme.StatusValid,
+			Certificate: apiURL + "/certificate",
+		},
+	}
+	certRes := &Resource{
+		Domain: "example.com",
+	}
+
+	valid, err := certifier.checkResponse(order, certRes, true, "DST Root CA X3")
+	require.NoError(t, err)
+
+	assert.True(t, valid)
+	assert.NotNil(t, certRes)
+	assert.Equal(t, "example.com", certRes.Domain)
+	assert.Contains(t, certRes.CertStableURL, "/certificate/1")
+	assert.Contains(t, certRes.CertURL, "/certificate/1")
+	assert.Nil(t, certRes.CSR)
+	assert.Nil(t, certRes.PrivateKey)
+	assert.Equal(t, certResponseMock2, string(certRes.Certificate), "Certificate")
+	assert.Equal(t, issuerMock2, string(certRes.IssuerCertificate), "IssuerCertificate")
+}
+
+func Test_Get(t *testing.T) {
+	mux, apiURL := tester.SetupFakeAPI(t)
+
+	mux.HandleFunc("/acme/cert/test-cert", func(w http.ResponseWriter, _ *http.Request) {
+		_, err := w.Write([]byte(certResponseMock))
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+	})
+
+	key, err := rsa.GenerateKey(rand.Reader, 2048)
+	require.NoError(t, err, "Could not generate test key")
+
+	core, err := api.New(http.DefaultClient, "lego-test", apiURL+"/dir", "", key)
+	require.NoError(t, err)
+
+	certifier := NewCertifier(core, &resolverMock{}, CertifierOptions{KeyType: certcrypto.RSA2048})
+
+	certRes, err := certifier.Get(apiURL+"/acme/cert/test-cert", true)
+	require.NoError(t, err)
+
+	assert.NotNil(t, certRes)
+	assert.Equal(t, "acme.wtf", certRes.Domain)
+	assert.Equal(t, apiURL+"/acme/cert/test-cert", certRes.CertStableURL)
+	assert.Equal(t, apiURL+"/acme/cert/test-cert", certRes.CertURL)
+	assert.Nil(t, certRes.CSR)
+	assert.Nil(t, certRes.PrivateKey)
+	assert.Equal(t, certResponseMock, string(certRes.Certificate), "Certificate")
+	assert.Equal(t, issuerMock, string(certRes.IssuerCertificate), "IssuerCertificate")
+}
+
+type resolverMock struct {
+	error error
+}
+
+func (r *resolverMock) Solve(_ []acme.Authorization) error {
+	return r.error
+}

certificate/errors.go

@@ -0,0 +1,30 @@
+package certificate
+
+import (
+	"bytes"
+	"fmt"
+	"sort"
+)
+
+// obtainError is returned when there are specific errors available per domain.
+type obtainError map[string]error
+
+func (e obtainError) Error() string {
+	buffer := bytes.NewBufferString("error: one or more domains had a problem:\n")
+
+	var domains []string
+	for domain := range e {
+		domains = append(domains, domain)
+	}
+	sort.Strings(domains)
+
+	for _, domain := range domains {
+		_, _ = fmt.Fprintf(buffer, "[%s] %s\n", domain, e[domain])
+	}
+	return buffer.String()
+}
+
+type domainError struct {
+	Domain string
+	Error  error
+}

certificate/renewal.go

@@ -0,0 +1,204 @@
+package certificate
+
+import (
+	"crypto"
+	"crypto/x509"
+	"crypto/x509/pkix"
+	"encoding/asn1"
+	"encoding/base64"
+	"encoding/json"
+	"fmt"
+	"math/big"
+	"math/rand"
+	"strings"
+	"time"
+
+	"github.com/go-acme/lego/v4/acme"
+)
+
+// RenewalInfoRequest contains the necessary renewal information.
+type RenewalInfoRequest struct {
+	Cert   *x509.Certificate
+	Issuer *x509.Certificate
+	// HashName must be the string representation of a crypto.Hash constant in the golang.org/x/crypto package (e.g. "SHA-256").
+	// The correct value depends on the algorithm expected by the ACME server's ARI implementation.
+	HashName string
+}
+
+// RenewalInfoResponse is a wrapper around acme.RenewalInfoResponse that provides a method for determining when to renew a certificate.
+type RenewalInfoResponse struct {
+	acme.RenewalInfoResponse
+}
+
+// ShouldRenewAt determines the optimal renewal time based on the current time (UTC),renewal window suggest by ARI, and the client's willingness to sleep.
+// It returns a pointer to a time.Time value indicating when the renewal should be attempted or nil if deferred until the next normal wake time.
+// This method implements the RECOMMENDED algorithm described in draft-ietf-acme-ari.
+//
+// - (4.1-11. Getting Renewal Information) https://datatracker.ietf.org/doc/draft-ietf-acme-ari/
+func (r *RenewalInfoResponse) ShouldRenewAt(now time.Time, willingToSleep time.Duration) *time.Time {
+	// Explicitly convert all times to UTC.
+	now = now.UTC()
+	start := r.SuggestedWindow.Start.UTC()
+	end := r.SuggestedWindow.End.UTC()
+
+	// Select a uniform random time within the suggested window.
+	window := end.Sub(start)
+	randomDuration := time.Duration(rand.Int63n(int64(window)))
+	rt := start.Add(randomDuration)
+
+	// If the selected time is in the past, attempt renewal immediately.
+	if rt.Before(now) {
+		return &now
+	}
+
+	// Otherwise, if the client can schedule itself to attempt renewal at exactly the selected time, do so.
+	willingToSleepUntil := now.Add(willingToSleep)
+	if willingToSleepUntil.After(rt) || willingToSleepUntil.Equal(rt) {
+		return &rt
+	}
+
+	// TODO: Otherwise, if the selected time is before the next time that the client would wake up normally, attempt renewal immediately.
+
+	// Otherwise, sleep until the next normal wake time, re-check ARI, and return to Step 1.
+	return nil
+}
+
+// GetRenewalInfo sends a request to the ACME server's renewalInfo endpoint to obtain a suggested renewal window.
+// The caller MUST provide the certificate and issuer certificate for the certificate they wish to renew.
+// The caller should attempt to renew the certificate at the time indicated by the ShouldRenewAt method of the returned RenewalInfoResponse object.
+//
+// Note: this endpoint is part of a draft specification, not all ACME servers will implement it.
+// This method will return api.ErrNoARI if the server does not advertise a renewal info endpoint.
+//
+// https://datatracker.ietf.org/doc/draft-ietf-acme-ari
+func (c *Certifier) GetRenewalInfo(req RenewalInfoRequest) (*RenewalInfoResponse, error) {
+	certID, err := makeCertID(req.Cert, req.Issuer, req.HashName)
+	if err != nil {
+		return nil, fmt.Errorf("error making certID: %w", err)
+	}
+
+	resp, err := c.core.Certificates.GetRenewalInfo(certID)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	var info RenewalInfoResponse
+	err = json.NewDecoder(resp.Body).Decode(&info)
+	if err != nil {
+		return nil, err
+	}
+	return &info, nil
+}
+
+// UpdateRenewalInfo sends an update to the ACME server's renewal info endpoint to indicate that the client has successfully replaced a certificate.
+// A certificate is considered replaced when its revocation would not disrupt any ongoing services,
+// for instance because it has been renewed and the new certificate is in use, or because it is no longer in use.
+//
+// Note: this endpoint is part of a draft specification, not all ACME servers will implement it.
+// This method will return api.ErrNoARI if the server does not advertise a renewal info endpoint.
+//
+// https://datatracker.ietf.org/doc/draft-ietf-acme-ari
+func (c *Certifier) UpdateRenewalInfo(req RenewalInfoRequest) error {
+	certID, err := makeCertID(req.Cert, req.Issuer, req.HashName)
+	if err != nil {
+		return fmt.Errorf("error making certID: %w", err)
+	}
+
+	_, err = c.core.Certificates.UpdateRenewalInfo(acme.RenewalInfoUpdateRequest{
+		CertID:   certID,
+		Replaced: true,
+	})
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// makeCertID returns a base64url-encoded string that uniquely identifies a certificate to endpoints
+// that implement the draft-ietf-acme-ari specification: https://datatracker.ietf.org/doc/draft-ietf-acme-ari.
+// hashName must be the string representation of a crypto.Hash constant in the golang.org/x/crypto package.
+// Supported hash functions are SHA-1, SHA-256, SHA-384, and SHA-512.
+func makeCertID(leaf, issuer *x509.Certificate, hashName string) (string, error) {
+	if leaf == nil {
+		return "", fmt.Errorf("leaf certificate is nil")
+	}
+	if issuer == nil {
+		return "", fmt.Errorf("issuer certificate is nil")
+	}
+
+	var hashFunc crypto.Hash
+	var oid asn1.ObjectIdentifier
+
+	switch hashName {
+	// The following correlation of hashFunc to OID is copied from a private mapping in golang.org/x/crypto/ocsp:
+	// https://cs.opensource.google/go/x/crypto/+/refs/tags/v0.8.0:ocsp/ocsp.go;l=156
+	case crypto.SHA1.String():
+		hashFunc = crypto.SHA1
+		oid = asn1.ObjectIdentifier([]int{1, 3, 14, 3, 2, 26})
+
+	case crypto.SHA256.String():
+		hashFunc = crypto.SHA256
+		oid = asn1.ObjectIdentifier([]int{2, 16, 840, 1, 101, 3, 4, 2, 1})
+
+	case crypto.SHA384.String():
+		hashFunc = crypto.SHA384
+		oid = asn1.ObjectIdentifier([]int{2, 16, 840, 1, 101, 3, 4, 2, 2})
+
+	case crypto.SHA512.String():
+		hashFunc = crypto.SHA512
+		oid = asn1.ObjectIdentifier([]int{2, 16, 840, 1, 101, 3, 4, 2, 3})
+
+	default:
+		return "", fmt.Errorf("hashName %q is not supported by this package", hashName)
+	}
+
+	if !hashFunc.Available() {
+		// This should never happen.
+		return "", fmt.Errorf("hash function %q is not available on your platform", hashFunc)
+	}
+
+	var spki struct {
+		Algorithm pkix.AlgorithmIdentifier
+		PublicKey asn1.BitString
+	}
+
+	_, err := asn1.Unmarshal(issuer.RawSubjectPublicKeyInfo, &spki)
+	if err != nil {
+		return "", err
+	}
+	h := hashFunc.New()
+	h.Write(spki.PublicKey.RightAlign())
+	issuerKeyHash := h.Sum(nil)
+
+	h.Reset()
+	h.Write(issuer.RawSubject)
+	issuerNameHash := h.Sum(nil)
+
+	type certID struct {
+		HashAlgorithm  pkix.AlgorithmIdentifier
+		IssuerNameHash []byte
+		IssuerKeyHash  []byte
+		SerialNumber   *big.Int
+	}
+
+	// DER-encode the CertID ASN.1 sequence [RFC6960].
+	certIDBytes, err := asn1.Marshal(certID{
+		HashAlgorithm: pkix.AlgorithmIdentifier{
+			Algorithm: oid,
+		},
+		IssuerNameHash: issuerNameHash,
+		IssuerKeyHash:  issuerKeyHash,
+		SerialNumber:   leaf.SerialNumber,
+	})
+	if err != nil {
+		return "", err
+	}
+
+	// base64url-encode [RFC4648] the bytes of the DER-encoded CertID ASN.1 sequence [RFC6960].
+	encodedBytes := base64.URLEncoding.EncodeToString(certIDBytes)
+
+	// Any trailing '=' characters MUST be stripped.
+	return strings.TrimRight(encodedBytes, "="), nil
+}

certificate/renewal_test.go

@@ -0,0 +1,356 @@
+package certificate
+
+import (
+	"crypto"
+	"crypto/rand"
+	"crypto/rsa"
+	"encoding/json"
+	"io"
+	"net/http"
+	"testing"
+	"time"
+
+	"github.com/go-acme/lego/v4/acme"
+	"github.com/go-acme/lego/v4/acme/api"
+	"github.com/go-acme/lego/v4/certcrypto"
+	"github.com/go-acme/lego/v4/platform/tester"
+	"github.com/go-jose/go-jose/v3"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+const (
+	ariLeafPEM = `-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----`
+	ariIssuerPEM = `-----BEGIN CERTIFICATE-----
+MIIDSzCCAjOgAwIBAgIIOhNWtJ7Igr0wDQYJKoZIhvcNAQELBQAwIDEeMBwGA1UE
+AxMVbWluaWNhIHJvb3QgY2EgM2ExMzU2MCAXDTIyMDMxNzE3NTEwOVoYDzIxMjIw
+MzE3MTc1MTA5WjAgMR4wHAYDVQQDExVtaW5pY2Egcm9vdCBjYSAzYTEzNTYwggEi
+MA0GCSqGSIb3DQEBAQUAA4IBDwAwggEKAoIBAQDc3P6cxcCZ7FQOQrYuigReSa8T
+IOPNKmlmX9OrTkPwjThiMNEETYKO1ea99yXPK36LUHC6OLmZ9jVQW2Ny1qwQCOy6
+TrquhnwKgtkBMDAZBLySSEXYdKL3r0jA4sflW130/OLwhstU/yv0J8+pj7eSVOR3
+zJBnYd1AqnXHRSwQm299KXgqema7uwsa8cgjrXsBzAhrwrvYlVhpWFSv3lQRDFQg
+c5Z/ZDV9i26qiaJsCCmdisJZWN7N2luUgxdRqzZ4Cr2Xoilg3T+hkb2y/d6ttsPA
+kaSA+pq3q6Qa7/qfGdT5WuUkcHpvKNRWqnwT9rCYlmG00r3hGgc42D/z1VvfAgMB
+AAGjgYYwgYMwDgYDVR0PAQH/BAQDAgKEMB0GA1UdJQQWMBQGCCsGAQUFBwMBBggr
+BgEFBQcDAjASBgNVHRMBAf8ECDAGAQH/AgEAMB0GA1UdDgQWBBQ4zzDRUaXHVKql
+STWkULGU4zGZpTAfBgNVHSMEGDAWgBQ4zzDRUaXHVKqlSTWkULGU4zGZpTANBgkq
+hkiG9w0BAQsFAAOCAQEArbDHhEjGedjb/YjU80aFTPWOMRjgyfQaPPgyxwX6Dsid
+1i2H1x4ud4ntz3sTZZxdQIrOqtlIWTWVCjpStwGxaC+38SdreiTTwy/nikXGa/6W
+ZyQRppR3agh/pl5LHVO6GsJz3YHa7wQhEhj3xsRwa9VrRXgHbLGbPOFVRTHPjaPg
+Gtsv2PN3f67DsPHF47ASqyOIRpLZPQmZIw6D3isJwfl+8CzvlB1veO0Q3uh08IJc
+fspYQXvFBzYa64uKxNAJMi4Pby8cf4r36Wnb7cL4ho3fOHgAltxdW8jgibRzqZpQ
+QKyxn2jX7kxeUDt0hFDJE8lOrhP73m66eBNzxe//FQ==
+-----END CERTIFICATE-----`
+	ariLeafCertID = "MFswCwYJYIZIAWUDBAIBBCCeWLRusNLb--vmWOkxm34qDjTMWkc3utIhOMoMwKDqbgQg2iiKWySZrD-6c88HMZ6vhIHZPamChLlzGHeZ7pTS8jYCCD6jRWhlRB8c"
+)
+
+func Test_makeCertID(t *testing.T) {
+	leaf, err := certcrypto.ParsePEMCertificate([]byte(ariLeafPEM))
+	require.NoError(t, err)
+	issuer, err := certcrypto.ParsePEMCertificate([]byte(ariIssuerPEM))
+	require.NoError(t, err)
+
+	actual, err := makeCertID(leaf, issuer, crypto.SHA256.String())
+	require.NoError(t, err)
+	assert.Equal(t, ariLeafCertID, actual)
+}
+
+func TestCertifier_GetRenewalInfo(t *testing.T) {
+	leaf, err := certcrypto.ParsePEMCertificate([]byte(ariLeafPEM))
+	require.NoError(t, err)
+	issuer, err := certcrypto.ParsePEMCertificate([]byte(ariIssuerPEM))
+	require.NoError(t, err)
+
+	// Test with a fake API.
+	mux, apiURL := tester.SetupFakeAPI(t)
+	mux.HandleFunc("/renewalInfo/"+ariLeafCertID, func(w http.ResponseWriter, r *http.Request) {
+		if r.Method != http.MethodGet {
+			http.Error(w, http.StatusText(http.StatusMethodNotAllowed), http.StatusMethodNotAllowed)
+			return
+		}
+
+		w.Header().Set("Content-Type", "application/json")
+		w.WriteHeader(http.StatusOK)
+		_, wErr := w.Write([]byte(`{
+				"suggestedWindow": {
+					"start": "2020-03-17T17:51:09Z",
+					"end": "2020-03-17T18:21:09Z"
+				},
+				"explanationUrl": "https://aricapable.ca/docs/renewal-advice/"
+			}
+		}`))
+		require.NoError(t, wErr)
+	})
+
+	key, err := rsa.GenerateKey(rand.Reader, 2048)
+	require.NoError(t, err, "Could not generate test key")
+
+	core, err := api.New(http.DefaultClient, "lego-test", apiURL+"/dir", "", key)
+	require.NoError(t, err)
+
+	certifier := NewCertifier(core, &resolverMock{}, CertifierOptions{KeyType: certcrypto.RSA2048})
+
+	ri, err := certifier.GetRenewalInfo(RenewalInfoRequest{leaf, issuer, crypto.SHA256.String()})
+	require.NoError(t, err)
+	require.NotNil(t, ri)
+	assert.Equal(t, "2020-03-17T17:51:09Z", ri.SuggestedWindow.Start.Format(time.RFC3339))
+	assert.Equal(t, "2020-03-17T18:21:09Z", ri.SuggestedWindow.End.Format(time.RFC3339))
+	assert.Equal(t, "https://aricapable.ca/docs/renewal-advice/", ri.ExplanationURL)
+}
+
+func TestCertifier_GetRenewalInfo_errors(t *testing.T) {
+	leaf, err := certcrypto.ParsePEMCertificate([]byte(ariLeafPEM))
+	require.NoError(t, err)
+	issuer, err := certcrypto.ParsePEMCertificate([]byte(ariIssuerPEM))
+	require.NoError(t, err)
+
+	key, err := rsa.GenerateKey(rand.Reader, 2048)
+	require.NoError(t, err, "Could not generate test key")
+
+	testCases := []struct {
+		desc       string
+		httpClient *http.Client
+		request    RenewalInfoRequest
+		handler    http.HandlerFunc
+	}{
+		{
+			desc:       "API timeout",
+			httpClient: &http.Client{Timeout: 500 * time.Millisecond}, // HTTP client that times out after 500ms.
+			request:    RenewalInfoRequest{leaf, issuer, crypto.SHA256.String()},
+			handler: func(w http.ResponseWriter, r *http.Request) {
+				// API that takes 2ms to respond.
+				time.Sleep(2 * time.Millisecond)
+			},
+		},
+		{
+			desc:       "API error",
+			httpClient: http.DefaultClient,
+			request:    RenewalInfoRequest{leaf, issuer, crypto.SHA256.String()},
+			handler: func(w http.ResponseWriter, r *http.Request) {
+				// API that responds with error instead of renewal info.
+				http.Error(w, http.StatusText(http.StatusBadRequest), http.StatusBadRequest)
+			},
+		},
+		{
+			desc:       "Issuer certificate is nil",
+			httpClient: http.DefaultClient,
+			request:    RenewalInfoRequest{leaf, nil, crypto.SHA256.String()},
+			handler: func(w http.ResponseWriter, r *http.Request) {
+				http.Error(w, http.StatusText(http.StatusBadRequest), http.StatusBadRequest)
+			},
+		},
+	}
+
+	for _, test := range testCases {
+		test := test
+		t.Run(test.desc, func(t *testing.T) {
+			t.Parallel()
+
+			mux, apiURL := tester.SetupFakeAPI(t)
+			mux.HandleFunc("/renewalInfo/"+ariLeafCertID, test.handler)
+
+			core, err := api.New(test.httpClient, "lego-test", apiURL+"/dir", "", key)
+			require.NoError(t, err)
+
+			certifier := NewCertifier(core, &resolverMock{}, CertifierOptions{KeyType: certcrypto.RSA2048})
+
+			response, err := certifier.GetRenewalInfo(test.request)
+			require.Error(t, err)
+			assert.Nil(t, response)
+		})
+	}
+}
+
+func TestCertifier_UpdateRenewalInfo(t *testing.T) {
+	leaf, err := certcrypto.ParsePEMCertificate([]byte(ariLeafPEM))
+	require.NoError(t, err)
+	issuer, err := certcrypto.ParsePEMCertificate([]byte(ariIssuerPEM))
+	require.NoError(t, err)
+
+	key, err := rsa.GenerateKey(rand.Reader, 2048)
+	require.NoError(t, err, "Could not generate test key")
+
+	// Test with a fake API.
+	mux, apiURL := tester.SetupFakeAPI(t)
+	mux.HandleFunc("/renewalInfo", func(w http.ResponseWriter, r *http.Request) {
+		if r.Method != http.MethodPost {
+			http.Error(w, http.StatusText(http.StatusMethodNotAllowed), http.StatusMethodNotAllowed)
+			return
+		}
+
+		body, rsbErr := readSignedBody(r, key)
+		if rsbErr != nil {
+			http.Error(w, rsbErr.Error(), http.StatusBadRequest)
+			return
+		}
+
+		var req acme.RenewalInfoUpdateRequest
+		err = json.Unmarshal(body, &req)
+		assert.NoError(t, err)
+		assert.True(t, req.Replaced)
+		assert.Equal(t, ariLeafCertID, req.CertID)
+
+		w.WriteHeader(http.StatusOK)
+	})
+
+	core, err := api.New(http.DefaultClient, "lego-test", apiURL+"/dir", "", key)
+	require.NoError(t, err)
+
+	certifier := NewCertifier(core, &resolverMock{}, CertifierOptions{KeyType: certcrypto.RSA2048})
+
+	err = certifier.UpdateRenewalInfo(RenewalInfoRequest{leaf, issuer, crypto.SHA256.String()})
+	require.NoError(t, err)
+}
+
+func TestCertifier_UpdateRenewalInfo_errors(t *testing.T) {
+	leaf, err := certcrypto.ParsePEMCertificate([]byte(ariLeafPEM))
+	require.NoError(t, err)
+	issuer, err := certcrypto.ParsePEMCertificate([]byte(ariIssuerPEM))
+	require.NoError(t, err)
+
+	key, err := rsa.GenerateKey(rand.Reader, 2048)
+	require.NoError(t, err, "Could not generate test key")
+
+	testCases := []struct {
+		desc    string
+		request RenewalInfoRequest
+	}{
+		{
+			desc:    "API error",
+			request: RenewalInfoRequest{leaf, issuer, crypto.SHA256.String()},
+		},
+		{
+			desc:    "Certificate is nil",
+			request: RenewalInfoRequest{nil, issuer, crypto.SHA256.String()},
+		},
+	}
+
+	for _, test := range testCases {
+		test := test
+		t.Run(test.desc, func(t *testing.T) {
+			t.Parallel()
+
+			mux, apiURL := tester.SetupFakeAPI(t)
+
+			// Always returns an error.
+			mux.HandleFunc("/renewalInfo", func(w http.ResponseWriter, r *http.Request) {
+				http.Error(w, http.StatusText(http.StatusBadRequest), http.StatusBadRequest)
+			})
+
+			core, err := api.New(http.DefaultClient, "lego-test", apiURL+"/dir", "", key)
+			require.NoError(t, err)
+
+			certifier := NewCertifier(core, &resolverMock{}, CertifierOptions{KeyType: certcrypto.RSA2048})
+
+			err = certifier.UpdateRenewalInfo(test.request)
+			require.Error(t, err)
+		})
+	}
+}
+
+func TestRenewalInfoResponse_ShouldRenew(t *testing.T) {
+	now := time.Now().UTC()
+
+	t.Run("Window is in the past", func(t *testing.T) {
+		ri := RenewalInfoResponse{
+			acme.RenewalInfoResponse{
+				SuggestedWindow: acme.Window{
+					Start: now.Add(-2 * time.Hour),
+					End:   now.Add(-1 * time.Hour),
+				},
+				ExplanationURL: "",
+			},
+		}
+
+		rt := ri.ShouldRenewAt(now, 0)
+		require.NotNil(t, rt)
+		assert.Equal(t, now, *rt)
+	})
+
+	t.Run("Window is in the future", func(t *testing.T) {
+		ri := RenewalInfoResponse{
+			acme.RenewalInfoResponse{
+				SuggestedWindow: acme.Window{
+					Start: now.Add(1 * time.Hour),
+					End:   now.Add(2 * time.Hour),
+				},
+				ExplanationURL: "",
+			},
+		}
+
+		rt := ri.ShouldRenewAt(now, 0)
+		assert.Nil(t, rt)
+	})
+
+	t.Run("Window is in the future, but caller is willing to sleep", func(t *testing.T) {
+		ri := RenewalInfoResponse{
+			acme.RenewalInfoResponse{
+				SuggestedWindow: acme.Window{
+					Start: now.Add(1 * time.Hour),
+					End:   now.Add(2 * time.Hour),
+				},
+				ExplanationURL: "",
+			},
+		}
+
+		rt := ri.ShouldRenewAt(now, 2*time.Hour)
+		require.NotNil(t, rt)
+		assert.True(t, rt.Before(now.Add(2*time.Hour)))
+	})
+
+	t.Run("Window is in the future, but caller isn't willing to sleep long enough", func(t *testing.T) {
+		ri := RenewalInfoResponse{
+			acme.RenewalInfoResponse{
+				SuggestedWindow: acme.Window{
+					Start: now.Add(1 * time.Hour),
+					End:   now.Add(2 * time.Hour),
+				},
+				ExplanationURL: "",
+			},
+		}
+
+		rt := ri.ShouldRenewAt(now, 59*time.Minute)
+		assert.Nil(t, rt)
+	})
+}
+
+func readSignedBody(r *http.Request, privateKey *rsa.PrivateKey) ([]byte, error) {
+	reqBody, err := io.ReadAll(r.Body)
+	if err != nil {
+		return nil, err
+	}
+
+	jws, err := jose.ParseSigned(string(reqBody))
+	if err != nil {
+		return nil, err
+	}
+
+	body, err := jws.Verify(&jose.JSONWebKey{
+		Key:       privateKey.Public(),
+		Algorithm: "RSA",
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	return body, nil
+}

challenge/challenges.go

@@ -0,0 +1,47 @@
+package challenge
+
+import (
+	"fmt"
+
+	"github.com/go-acme/lego/v4/acme"
+)
+
+// Type is a string that identifies a particular challenge type and version of ACME challenge.
+type Type string
+
+const (
+	// HTTP01 is the "http-01" ACME challenge https://www.rfc-editor.org/rfc/rfc8555.html#section-8.3
+	// Note: ChallengePath returns the URL path to fulfill this challenge.
+	HTTP01 = Type("http-01")
+
+	// DNS01 is the "dns-01" ACME challenge https://www.rfc-editor.org/rfc/rfc8555.html#section-8.4
+	// Note: GetRecord returns a DNS record which will fulfill this challenge.
+	DNS01 = Type("dns-01")
+
+	// TLSALPN01 is the "tls-alpn-01" ACME challenge https://www.rfc-editor.org/rfc/rfc8737.html
+	TLSALPN01 = Type("tls-alpn-01")
+
+	// NNS01 is the "nns-01" ACME challenge
+	NNS01 = Type("nns-01")
+)
+
+func (t Type) String() string {
+	return string(t)
+}
+
+func FindChallenge(chlgType Type, authz acme.Authorization) (acme.Challenge, error) {
+	for _, chlg := range authz.Challenges {
+		if chlg.Type == string(chlgType) {
+			return chlg, nil
+		}
+	}
+
+	return acme.Challenge{}, fmt.Errorf("[%s] acme: unable to find challenge %s", GetTargetedDomain(authz), chlgType)
+}
+
+func GetTargetedDomain(authz acme.Authorization) string {
+	if authz.Wildcard {
+		return "*." + authz.Identifier.Value
+	}
+	return authz.Identifier.Value
+}

challenge/dns01/cname.go

@@ -0,0 +1,20 @@
+package dns01
+
+import (
+	"strings"
+
+	"github.com/miekg/dns"
+)
+
+// Update FQDN with CNAME if any.
+func updateDomainWithCName(r *dns.Msg, fqdn string) string {
+	for _, rr := range r.Answer {
+		if cn, ok := rr.(*dns.CNAME); ok {
+			if strings.EqualFold(cn.Hdr.Name, fqdn) {
+				return cn.Target
+			}
+		}
+	}
+
+	return fqdn
+}

challenge/dns01/cname_test.go

@@ -0,0 +1,35 @@
+package dns01
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/miekg/dns"
+	"github.com/stretchr/testify/assert"
+)
+
+func Test_updateDomainWithCName_caseInsensitive(t *testing.T) {
+	qname := "_acme-challenge.uppercase-test.example.com."
+	cnameTarget := "_acme-challenge.uppercase-test.cname-target.example.com."
+
+	msg := &dns.Msg{
+		MsgHdr: dns.MsgHdr{
+			Authoritative: true,
+		},
+		Answer: []dns.RR{
+			&dns.CNAME{
+				Hdr: dns.RR_Header{
+					Name:   strings.ToUpper(qname), // CNAME names are case-insensitive
+					Rrtype: dns.TypeCNAME,
+					Class:  dns.ClassINET,
+					Ttl:    3600,
+				},
+				Target: cnameTarget,
+			},
+		},
+	}
+
+	fqdn := updateDomainWithCName(msg, qname)
+
+	assert.Equal(t, cnameTarget, fqdn)
+}

challenge/dns01/dns_challenge.go

@@ -0,0 +1,238 @@
+package dns01
+
+import (
+	"crypto/sha256"
+	"encoding/base64"
+	"fmt"
+	"os"
+	"strconv"
+	"time"
+
+	"github.com/go-acme/lego/v4/acme"
+	"github.com/go-acme/lego/v4/acme/api"
+	"github.com/go-acme/lego/v4/challenge"
+	"github.com/go-acme/lego/v4/log"
+	"github.com/go-acme/lego/v4/platform/wait"
+	"github.com/miekg/dns"
+)
+
+const (
+	// DefaultPropagationTimeout default propagation timeout.
+	DefaultPropagationTimeout = 60 * time.Second
+
+	// DefaultPollingInterval default polling interval.
+	DefaultPollingInterval = 2 * time.Second
+
+	// DefaultTTL default TTL.
+	DefaultTTL = 120
+)
+
+type ValidateFunc func(core *api.Core, domain string, chlng acme.Challenge) error
+
+type ChallengeOption func(*Challenge) error
+
+// CondOption Conditional challenge option.
+func CondOption(condition bool, opt ChallengeOption) ChallengeOption {
+	if !condition {
+		// NoOp options
+		return func(*Challenge) error {
+			return nil
+		}
+	}
+	return opt
+}
+
+// Challenge implements the dns-01 challenge.
+type Challenge struct {
+	core       *api.Core
+	validate   ValidateFunc
+	provider   challenge.Provider
+	preCheck   preCheck
+	dnsTimeout time.Duration
+}
+
+func NewChallenge(core *api.Core, validate ValidateFunc, provider challenge.Provider, opts ...ChallengeOption) *Challenge {
+	chlg := &Challenge{
+		core:       core,
+		validate:   validate,
+		provider:   provider,
+		preCheck:   newPreCheck(),
+		dnsTimeout: 10 * time.Second,
+	}
+
+	for _, opt := range opts {
+		err := opt(chlg)
+		if err != nil {
+			log.Infof("challenge option error: %v", err)
+		}
+	}
+
+	return chlg
+}
+
+// PreSolve just submits the txt record to the dns provider.
+// It does not validate record propagation, or do anything at all with the acme server.
+func (c *Challenge) PreSolve(authz acme.Authorization) error {
+	domain := challenge.GetTargetedDomain(authz)
+	log.Infof("[%s] acme: Preparing to solve DNS-01", domain)
+
+	chlng, err := challenge.FindChallenge(challenge.DNS01, authz)
+	if err != nil {
+		return err
+	}
+
+	if c.provider == nil {
+		return fmt.Errorf("[%s] acme: no DNS Provider configured", domain)
+	}
+
+	// Generate the Key Authorization for the challenge
+	keyAuth, err := c.core.GetKeyAuthorization(chlng.Token)
+	if err != nil {
+		return err
+	}
+
+	err = c.provider.Present(authz.Identifier.Value, chlng.Token, keyAuth)
+	if err != nil {
+		return fmt.Errorf("[%s] acme: error presenting token: %w", domain, err)
+	}
+
+	return nil
+}
+
+func (c *Challenge) Solve(authz acme.Authorization) error {
+	domain := challenge.GetTargetedDomain(authz)
+	log.Infof("[%s] acme: Trying to solve DNS-01", domain)
+
+	chlng, err := challenge.FindChallenge(challenge.DNS01, authz)
+	if err != nil {
+		return err
+	}
+
+	// Generate the Key Authorization for the challenge
+	keyAuth, err := c.core.GetKeyAuthorization(chlng.Token)
+	if err != nil {
+		return err
+	}
+
+	info := GetChallengeInfo(authz.Identifier.Value, keyAuth)
+
+	var timeout, interval time.Duration
+	switch provider := c.provider.(type) {
+	case challenge.ProviderTimeout:
+		timeout, interval = provider.Timeout()
+	default:
+		timeout, interval = DefaultPropagationTimeout, DefaultPollingInterval
+	}
+
+	log.Infof("[%s] acme: Checking DNS record propagation using %+v", domain, recursiveNameservers)
+
+	time.Sleep(interval)
+
+	err = wait.For("propagation", timeout, interval, func() (bool, error) {
+		stop, errP := c.preCheck.call(domain, info.EffectiveFQDN, info.Value)
+		if !stop || errP != nil {
+			log.Infof("[%s] acme: Waiting for DNS record propagation.", domain)
+		}
+		return stop, errP
+	})
+	if err != nil {
+		return err
+	}
+
+	chlng.KeyAuthorization = keyAuth
+	return c.validate(c.core, domain, chlng)
+}
+
+// CleanUp cleans the challenge.
+func (c *Challenge) CleanUp(authz acme.Authorization) error {
+	log.Infof("[%s] acme: Cleaning DNS-01 challenge", challenge.GetTargetedDomain(authz))
+
+	chlng, err := challenge.FindChallenge(challenge.DNS01, authz)
+	if err != nil {
+		return err
+	}
+
+	keyAuth, err := c.core.GetKeyAuthorization(chlng.Token)
+	if err != nil {
+		return err
+	}
+
+	return c.provider.CleanUp(authz.Identifier.Value, chlng.Token, keyAuth)
+}
+
+func (c *Challenge) Sequential() (bool, time.Duration) {
+	if p, ok := c.provider.(sequential); ok {
+		return ok, p.Sequential()
+	}
+	return false, 0
+}
+
+type sequential interface {
+	Sequential() time.Duration
+}
+
+// GetRecord returns a DNS record which will fulfill the `dns-01` challenge.
+// Deprecated: use GetChallengeInfo instead.
+func GetRecord(domain, keyAuth string) (fqdn, value string) {
+	info := GetChallengeInfo(domain, keyAuth)
+
+	return info.EffectiveFQDN, info.Value
+}
+
+// ChallengeInfo contains the information use to create the TXT record.
+type ChallengeInfo struct {
+	// FQDN is the full-qualified challenge domain (i.e. `_acme-challenge.[domain].`)
+	FQDN string
+
+	// EffectiveFQDN contains the resulting FQDN after the CNAMEs resolutions.
+	EffectiveFQDN string
+
+	// Value contains the value for the TXT record.
+	Value string
+}
+
+// GetChallengeInfo returns information used to create a DNS record which will fulfill the `dns-01` challenge.
+func GetChallengeInfo(domain, keyAuth string) ChallengeInfo {
+	keyAuthShaBytes := sha256.Sum256([]byte(keyAuth))
+	// base64URL encoding without padding
+	value := base64.RawURLEncoding.EncodeToString(keyAuthShaBytes[:sha256.Size])
+
+	ok, _ := strconv.ParseBool(os.Getenv("LEGO_DISABLE_CNAME_SUPPORT"))
+
+	return ChallengeInfo{
+		Value:         value,
+		FQDN:          getChallengeFQDN(domain, false),
+		EffectiveFQDN: getChallengeFQDN(domain, !ok),
+	}
+}
+
+func getChallengeFQDN(domain string, followCNAME bool) string {
+	fqdn := fmt.Sprintf("_acme-challenge.%s.", domain)
+
+	if !followCNAME {
+		return fqdn
+	}
+
+	// recursion counter so it doesn't spin out of control
+	for limit := 0; limit < 50; limit++ {
+		// Keep following CNAMEs
+		r, err := dnsQuery(fqdn, dns.TypeCNAME, recursiveNameservers, true)
+
+		if err != nil || r.Rcode != dns.RcodeSuccess {
+			// No more CNAME records to follow, exit
+			break
+		}
+
+		// Check if the domain has CNAME then use that
+		cname := updateDomainWithCName(r, fqdn)
+		if cname == fqdn {
+			break
+		}
+
+		log.Infof("Found CNAME entry for %q: %q", fqdn, cname)
+
+		fqdn = cname
+	}
+
+	return fqdn
+}

challenge/dns01/dns_challenge_manual.go

@@ -0,0 +1,59 @@
+package dns01
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+	"time"
+)
+
+const (
+	dnsTemplate = `%s %d IN TXT %q`
+)
+
+// DNSProviderManual is an implementation of the ChallengeProvider interface.
+type DNSProviderManual struct{}
+
+// NewDNSProviderManual returns a DNSProviderManual instance.
+func NewDNSProviderManual() (*DNSProviderManual, error) {
+	return &DNSProviderManual{}, nil
+}
+
+// Present prints instructions for manually creating the TXT record.
+func (*DNSProviderManual) Present(domain, token, keyAuth string) error {
+	info := GetChallengeInfo(domain, keyAuth)
+
+	authZone, err := FindZoneByFqdn(info.EffectiveFQDN)
+	if err != nil {
+		return err
+	}
+
+	fmt.Printf("lego: Please create the following TXT record in your %s zone:\n", authZone)
+	fmt.Printf(dnsTemplate+"\n", info.EffectiveFQDN, DefaultTTL, info.Value)
+	fmt.Printf("lego: Press 'Enter' when you are done\n")
+
+	_, err = bufio.NewReader(os.Stdin).ReadBytes('\n')
+
+	return err
+}
+
+// CleanUp prints instructions for manually removing the TXT record.
+func (*DNSProviderManual) CleanUp(domain, token, keyAuth string) error {
+	info := GetChallengeInfo(domain, keyAuth)
+
+	authZone, err := FindZoneByFqdn(info.EffectiveFQDN)
+	if err != nil {
+		return err
+	}
+
+	fmt.Printf("lego: You can now remove this TXT record from your %s zone:\n", authZone)
+	fmt.Printf(dnsTemplate+"\n", info.EffectiveFQDN, DefaultTTL, "...")
+
+	return nil
+}
+
+// Sequential All DNS challenges for this provider will be resolved sequentially.
+// Returns the interval between each iteration.
+func (d *DNSProviderManual) Sequential() time.Duration {
+	return DefaultPropagationTimeout
+}

challenge/dns01/dns_challenge_manual_test.go

@@ -0,0 +1,60 @@
+package dns01
+
+import (
+	"io"
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestDNSProviderManual(t *testing.T) {
+	backupStdin := os.Stdin
+	defer func() { os.Stdin = backupStdin }()
+
+	testCases := []struct {
+		desc        string
+		input       string
+		expectError bool
+	}{
+		{
+			desc:  "Press enter",
+			input: "ok\n",
+		},
+		{
+			desc:        "Missing enter",
+			input:       "ok",
+			expectError: true,
+		},
+	}
+
+	for _, test := range testCases {
+		t.Run(test.desc, func(t *testing.T) {
+			file, err := os.CreateTemp("", "lego_test")
+			assert.NoError(t, err)
+			defer func() { _ = os.Remove(file.Name()) }()
+
+			_, err = file.WriteString(test.input)
+			assert.NoError(t, err)
+
+			_, err = file.Seek(0, io.SeekStart)
+			assert.NoError(t, err)
+
+			os.Stdin = file
+
+			manualProvider, err := NewDNSProviderManual()
+			require.NoError(t, err)
+
+			err = manualProvider.Present("example.com", "", "")
+			if test.expectError {
+				require.Error(t, err)
+			} else {
+				require.NoError(t, err)
+
+				err = manualProvider.CleanUp("example.com", "", "")
+				require.NoError(t, err)
+			}
+		})
+	}
+}

challenge/dns01/dns_challenge_test.go

@@ -0,0 +1,283 @@
+package dns01
+
+import (
+	"crypto/rand"
+	"crypto/rsa"
+	"errors"
+	"net/http"
+	"testing"
+	"time"
+
+	"github.com/go-acme/lego/v4/acme"
+	"github.com/go-acme/lego/v4/acme/api"
+	"github.com/go-acme/lego/v4/challenge"
+	"github.com/go-acme/lego/v4/platform/tester"
+	"github.com/stretchr/testify/require"
+)
+
+type providerMock struct {
+	present, cleanUp error
+}
+
+func (p *providerMock) Present(domain, token, keyAuth string) error { return p.present }
+func (p *providerMock) CleanUp(domain, token, keyAuth string) error { return p.cleanUp }
+
+type providerTimeoutMock struct {
+	present, cleanUp  error
+	timeout, interval time.Duration
+}
+
+func (p *providerTimeoutMock) Present(domain, token, keyAuth string) error { return p.present }
+func (p *providerTimeoutMock) CleanUp(domain, token, keyAuth string) error { return p.cleanUp }
+func (p *providerTimeoutMock) Timeout() (time.Duration, time.Duration)     { return p.timeout, p.interval }
+
+func TestChallenge_PreSolve(t *testing.T) {
+	_, apiURL := tester.SetupFakeAPI(t)
+
+	privateKey, err := rsa.GenerateKey(rand.Reader, 512)
+	require.NoError(t, err)
+
+	core, err := api.New(http.DefaultClient, "lego-test", apiURL+"/dir", "", privateKey)
+	require.NoError(t, err)
+
+	testCases := []struct {
+		desc        string
+		validate    ValidateFunc
+		preCheck    WrapPreCheckFunc
+		provider    challenge.Provider
+		expectError bool
+	}{
+		{
+			desc:     "success",
+			validate: func(_ *api.Core, _ string, _ acme.Challenge) error { return nil },
+			preCheck: func(_, _, _ string, _ PreCheckFunc) (bool, error) { return true, nil },
+			provider: &providerMock{},
+		},
+		{
+			desc:     "validate fail",
+			validate: func(_ *api.Core, _ string, _ acme.Challenge) error { return errors.New("OOPS") },
+			preCheck: func(_, _, _ string, _ PreCheckFunc) (bool, error) { return true, nil },
+			provider: &providerMock{
+				present: nil,
+				cleanUp: nil,
+			},
+		},
+		{
+			desc:     "preCheck fail",
+			validate: func(_ *api.Core, _ string, _ acme.Challenge) error { return nil },
+			preCheck: func(_, _, _ string, _ PreCheckFunc) (bool, error) { return false, errors.New("OOPS") },
+			provider: &providerTimeoutMock{
+				timeout:  2 * time.Second,
+				interval: 500 * time.Millisecond,
+			},
+		},
+		{
+			desc:     "present fail",
+			validate: func(_ *api.Core, _ string, _ acme.Challenge) error { return nil },
+			preCheck: func(_, _, _ string, _ PreCheckFunc) (bool, error) { return true, nil },
+			provider: &providerMock{
+				present: errors.New("OOPS"),
+			},
+			expectError: true,
+		},
+		{
+			desc:     "cleanUp fail",
+			validate: func(_ *api.Core, _ string, _ acme.Challenge) error { return nil },
+			preCheck: func(_, _, _ string, _ PreCheckFunc) (bool, error) { return true, nil },
+			provider: &providerMock{
+				cleanUp: errors.New("OOPS"),
+			},
+		},
+	}
+
+	for _, test := range testCases {
+		t.Run(test.desc, func(t *testing.T) {
+			chlg := NewChallenge(core, test.validate, test.provider, WrapPreCheck(test.preCheck))
+
+			authz := acme.Authorization{
+				Identifier: acme.Identifier{
+					Value: "example.com",
+				},
+				Challenges: []acme.Challenge{
+					{Type: challenge.DNS01.String()},
+				},
+			}
+
+			err = chlg.PreSolve(authz)
+			if test.expectError {
+				require.Error(t, err)
+			} else {
+				require.NoError(t, err)
+			}
+		})
+	}
+}
+
+func TestChallenge_Solve(t *testing.T) {
+	_, apiURL := tester.SetupFakeAPI(t)
+
+	privateKey, err := rsa.GenerateKey(rand.Reader, 512)
+	require.NoError(t, err)
+
+	core, err := api.New(http.DefaultClient, "lego-test", apiURL+"/dir", "", privateKey)
+	require.NoError(t, err)
+
+	testCases := []struct {
+		desc        string
+		validate    ValidateFunc
+		preCheck    WrapPreCheckFunc
+		provider    challenge.Provider
+		expectError bool
+	}{
+		{
+			desc:     "success",
+			validate: func(_ *api.Core, _ string, _ acme.Challenge) error { return nil },
+			preCheck: func(_, _, _ string, _ PreCheckFunc) (bool, error) { return true, nil },
+			provider: &providerMock{},
+		},
+		{
+			desc:     "validate fail",
+			validate: func(_ *api.Core, _ string, _ acme.Challenge) error { return errors.New("OOPS") },
+			preCheck: func(_, _, _ string, _ PreCheckFunc) (bool, error) { return true, nil },
+			provider: &providerMock{
+				present: nil,
+				cleanUp: nil,
+			},
+			expectError: true,
+		},
+		{
+			desc:     "preCheck fail",
+			validate: func(_ *api.Core, _ string, _ acme.Challenge) error { return nil },
+			preCheck: func(_, _, _ string, _ PreCheckFunc) (bool, error) { return false, errors.New("OOPS") },
+			provider: &providerTimeoutMock{
+				timeout:  2 * time.Second,
+				interval: 500 * time.Millisecond,
+			},
+			expectError: true,
+		},
+		{
+			desc:     "present fail",
+			validate: func(_ *api.Core, _ string, _ acme.Challenge) error { return nil },
+			preCheck: func(_, _, _ string, _ PreCheckFunc) (bool, error) { return true, nil },
+			provider: &providerMock{
+				present: errors.New("OOPS"),
+			},
+		},
+		{
+			desc:     "cleanUp fail",
+			validate: func(_ *api.Core, _ string, _ acme.Challenge) error { return nil },
+			preCheck: func(_, _, _ string, _ PreCheckFunc) (bool, error) { return true, nil },
+			provider: &providerMock{
+				cleanUp: errors.New("OOPS"),
+			},
+		},
+	}
+
+	for _, test := range testCases {
+		t.Run(test.desc, func(t *testing.T) {
+			var options []ChallengeOption
+			if test.preCheck != nil {
+				options = append(options, WrapPreCheck(test.preCheck))
+			}
+			chlg := NewChallenge(core, test.validate, test.provider, options...)
+
+			authz := acme.Authorization{
+				Identifier: acme.Identifier{
+					Value: "example.com",
+				},
+				Challenges: []acme.Challenge{
+					{Type: challenge.DNS01.String()},
+				},
+			}
+
+			err = chlg.Solve(authz)
+			if test.expectError {
+				require.Error(t, err)
+			} else {
+				require.NoError(t, err)
+			}
+		})
+	}
+}
+
+func TestChallenge_CleanUp(t *testing.T) {
+	_, apiURL := tester.SetupFakeAPI(t)
+
+	privateKey, err := rsa.GenerateKey(rand.Reader, 512)
+	require.NoError(t, err)
+
+	core, err := api.New(http.DefaultClient, "lego-test", apiURL+"/dir", "", privateKey)
+	require.NoError(t, err)
+
+	testCases := []struct {
+		desc        string
+		validate    ValidateFunc
+		preCheck    WrapPreCheckFunc
+		provider    challenge.Provider
+		expectError bool
+	}{
+		{
+			desc:     "success",
+			validate: func(_ *api.Core, _ string, _ acme.Challenge) error { return nil },
+			preCheck: func(_, _, _ string, _ PreCheckFunc) (bool, error) { return true, nil },
+			provider: &providerMock{},
+		},
+		{
+			desc:     "validate fail",
+			validate: func(_ *api.Core, _ string, _ acme.Challenge) error { return errors.New("OOPS") },
+			preCheck: func(_, _, _ string, _ PreCheckFunc) (bool, error) { return true, nil },
+			provider: &providerMock{
+				present: nil,
+				cleanUp: nil,
+			},
+		},
+		{
+			desc:     "preCheck fail",
+			validate: func(_ *api.Core, _ string, _ acme.Challenge) error { return nil },
+			preCheck: func(_, _, _ string, _ PreCheckFunc) (bool, error) { return false, errors.New("OOPS") },
+			provider: &providerTimeoutMock{
+				timeout:  2 * time.Second,
+				interval: 500 * time.Millisecond,
+			},
+		},
+		{
+			desc:     "present fail",
+			validate: func(_ *api.Core, _ string, _ acme.Challenge) error { return nil },
+			preCheck: func(_, _, _ string, _ PreCheckFunc) (bool, error) { return true, nil },
+			provider: &providerMock{
+				present: errors.New("OOPS"),
+			},
+		},
+		{
+			desc:     "cleanUp fail",
+			validate: func(_ *api.Core, _ string, _ acme.Challenge) error { return nil },
+			preCheck: func(_, _, _ string, _ PreCheckFunc) (bool, error) { return true, nil },
+			provider: &providerMock{
+				cleanUp: errors.New("OOPS"),
+			},
+			expectError: true,
+		},
+	}
+
+	for _, test := range testCases {
+		t.Run(test.desc, func(t *testing.T) {
+			chlg := NewChallenge(core, test.validate, test.provider, WrapPreCheck(test.preCheck))
+
+			authz := acme.Authorization{
+				Identifier: acme.Identifier{
+					Value: "example.com",
+				},
+				Challenges: []acme.Challenge{
+					{Type: challenge.DNS01.String()},
+				},
+			}
+
+			err = chlg.CleanUp(authz)
+			if test.expectError {
+				require.Error(t, err)
+			} else {
+				require.NoError(t, err)
+			}
+		})
+	}
+}

challenge/dns01/domain.go

@@ -0,0 +1,24 @@
+package dns01
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/miekg/dns"
+)
+
+// ExtractSubDomain extracts the subdomain part from a domain and a zone.
+func ExtractSubDomain(domain, zone string) (string, error) {
+	canonDomain := dns.Fqdn(domain)
+	canonZone := dns.Fqdn(zone)
+
+	if canonDomain == canonZone {
+		return "", fmt.Errorf("no subdomain because the domain and the zone are identical: %s", canonDomain)
+	}
+
+	if !dns.IsSubDomain(canonZone, canonDomain) {
+		return "", fmt.Errorf("%s is not a subdomain of %s", canonDomain, canonZone)
+	}
+
+	return strings.TrimSuffix(canonDomain, "."+canonZone), nil
+}

challenge/dns01/domain_test.go

@@ -0,0 +1,104 @@
+package dns01
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestExtractSubDomain(t *testing.T) {
+	testCases := []struct {
+		desc     string
+		domain   string
+		zone     string
+		expected string
+	}{
+		{
+			desc:     "no FQDN",
+			domain:   "_acme-challenge.example.com",
+			zone:     "example.com",
+			expected: "_acme-challenge",
+		},
+		{
+			desc:     "no FQDN zone",
+			domain:   "_acme-challenge.example.com.",
+			zone:     "example.com",
+			expected: "_acme-challenge",
+		},
+		{
+			desc:     "no FQDN domain",
+			domain:   "_acme-challenge.example.com",
+			zone:     "example.com.",
+			expected: "_acme-challenge",
+		},
+		{
+			desc:     "FQDN",
+			domain:   "_acme-challenge.example.com.",
+			zone:     "example.com.",
+			expected: "_acme-challenge",
+		},
+		{
+			desc:     "multi-level subdomain",
+			domain:   "_acme-challenge.one.example.com.",
+			zone:     "example.com.",
+			expected: "_acme-challenge.one",
+		},
+	}
+
+	for _, test := range testCases {
+		test := test
+		t.Run(test.desc, func(t *testing.T) {
+			t.Parallel()
+
+			subDomain, err := ExtractSubDomain(test.domain, test.zone)
+			require.NoError(t, err)
+
+			assert.Equal(t, test.expected, subDomain)
+		})
+	}
+}
+
+func TestExtractSubDomain_errors(t *testing.T) {
+	testCases := []struct {
+		desc   string
+		domain string
+		zone   string
+	}{
+		{
+			desc:   "same domain",
+			domain: "example.com",
+			zone:   "example.com",
+		},
+		{
+			desc:   "same domain, no FQDN zone",
+			domain: "example.com.",
+			zone:   "example.com",
+		},
+		{
+			desc:   "same domain, no FQDN domain",
+			domain: "example.com",
+			zone:   "example.com.",
+		},
+		{
+			desc:   "same domain, FQDN",
+			domain: "example.com.",
+			zone:   "example.com.",
+		},
+		{
+			desc:   "zone and domain are unrelated",
+			domain: "_acme-challenge.example.com",
+			zone:   "example.org",
+		},
+	}
+
+	for _, test := range testCases {
+		test := test
+		t.Run(test.desc, func(t *testing.T) {
+			t.Parallel()
+
+			_, err := ExtractSubDomain(test.domain, test.zone)
+			require.Error(t, err)
+		})
+	}
+}

challenge/dns01/fixtures/resolv.conf.1

@@ -0,0 +1,5 @@
+domain company.com
+nameserver 10.200.3.249
+nameserver 10.200.3.250:5353
+nameserver 2001:4860:4860::8844
+nameserver [10.0.0.1]:5353

challenge/dns01/fqdn.go

@@ -0,0 +1,19 @@
+package dns01
+
+// ToFqdn converts the name into a fqdn appending a trailing dot.
+func ToFqdn(name string) string {
+	n := len(name)
+	if n == 0 || name[n-1] == '.' {
+		return name
+	}
+	return name + "."
+}
+
+// UnFqdn converts the fqdn into a name removing the trailing dot.
+func UnFqdn(name string) string {
+	n := len(name)
+	if n != 0 && name[n-1] == '.' {
+		return name[:n-1]
+	}
+	return name
+}

challenge/dns01/fqdn_test.go

@@ -0,0 +1,66 @@
+package dns01
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestToFqdn(t *testing.T) {
+	testCases := []struct {
+		desc     string
+		domain   string
+		expected string
+	}{
+		{
+			desc:     "simple",
+			domain:   "foo.bar.com",
+			expected: "foo.bar.com.",
+		},
+		{
+			desc:     "already FQDN",
+			domain:   "foo.bar.com.",
+			expected: "foo.bar.com.",
+		},
+	}
+
+	for _, test := range testCases {
+		test := test
+		t.Run(test.desc, func(t *testing.T) {
+			t.Parallel()
+
+			fqdn := ToFqdn(test.domain)
+			assert.Equal(t, test.expected, fqdn)
+		})
+	}
+}
+
+func TestUnFqdn(t *testing.T) {
+	testCases := []struct {
+		desc     string
+		fqdn     string
+		expected string
+	}{
+		{
+			desc:     "simple",
+			fqdn:     "foo.bar.com.",
+			expected: "foo.bar.com",
+		},
+		{
+			desc:     "already domain",
+			fqdn:     "foo.bar.com",
+			expected: "foo.bar.com",
+		},
+	}
+
+	for _, test := range testCases {
+		test := test
+		t.Run(test.desc, func(t *testing.T) {
+			t.Parallel()
+
+			domain := UnFqdn(test.fqdn)
+
+			assert.Equal(t, test.expected, domain)
+		})
+	}
+}

challenge/dns01/nameserver.go

@@ -0,0 +1,290 @@
+package dns01
+
+import (
+	"errors"
+	"fmt"
+	"net"
+	"os"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/miekg/dns"
+)
+
+const defaultResolvConf = "/etc/resolv.conf"
+
+var (
+	fqdnSoaCache   = map[string]*soaCacheEntry{}
+	muFqdnSoaCache sync.Mutex
+)
+
+var defaultNameservers = []string{
+	"google-public-dns-a.google.com:53",
+	"google-public-dns-b.google.com:53",
+}
+
+// recursiveNameservers are used to pre-check DNS propagation.
+var recursiveNameservers = getNameservers(defaultResolvConf, defaultNameservers)
+
+// soaCacheEntry holds a cached SOA record (only selected fields).
+type soaCacheEntry struct {
+	zone      string    // zone apex (a domain name)
+	primaryNs string    // primary nameserver for the zone apex
+	expires   time.Time // time when this cache entry should be evicted
+}
+
+func newSoaCacheEntry(soa *dns.SOA) *soaCacheEntry {
+	return &soaCacheEntry{
+		zone:      soa.Hdr.Name,
+		primaryNs: soa.Ns,
+		expires:   time.Now().Add(time.Duration(soa.Refresh) * time.Second),
+	}
+}
+
+// isExpired checks whether a cache entry should be considered expired.
+func (cache *soaCacheEntry) isExpired() bool {
+	return time.Now().After(cache.expires)
+}
+
+// ClearFqdnCache clears the cache of fqdn to zone mappings. Primarily used in testing.
+func ClearFqdnCache() {
+	muFqdnSoaCache.Lock()
+	fqdnSoaCache = map[string]*soaCacheEntry{}
+	muFqdnSoaCache.Unlock()
+}
+
+func AddDNSTimeout(timeout time.Duration) ChallengeOption {
+	return func(_ *Challenge) error {
+		dnsTimeout = timeout
+		return nil
+	}
+}
+
+func AddRecursiveNameservers(nameservers []string) ChallengeOption {
+	return func(_ *Challenge) error {
+		recursiveNameservers = ParseNameservers(nameservers)
+		return nil
+	}
+}
+
+// getNameservers attempts to get systems nameservers before falling back to the defaults.
+func getNameservers(path string, defaults []string) []string {
+	config, err := dns.ClientConfigFromFile(path)
+	if err != nil || len(config.Servers) == 0 {
+		return defaults
+	}
+
+	return ParseNameservers(config.Servers)
+}
+
+func ParseNameservers(servers []string) []string {
+	var resolvers []string
+	for _, resolver := range servers {
+		// ensure all servers have a port number
+		if _, _, err := net.SplitHostPort(resolver); err != nil {
+			resolvers = append(resolvers, net.JoinHostPort(resolver, "53"))
+		} else {
+			resolvers = append(resolvers, resolver)
+		}
+	}
+	return resolvers
+}
+
+// lookupNameservers returns the authoritative nameservers for the given fqdn.
+func lookupNameservers(fqdn string) ([]string, error) {
+	var authoritativeNss []string
+
+	zone, err := FindZoneByFqdn(fqdn)
+	if err != nil {
+		return nil, fmt.Errorf("could not determine the zone: %w", err)
+	}
+
+	r, err := dnsQuery(zone, dns.TypeNS, recursiveNameservers, true)
+	if err != nil {
+		return nil, err
+	}
+
+	for _, rr := range r.Answer {
+		if ns, ok := rr.(*dns.NS); ok {
+			authoritativeNss = append(authoritativeNss, strings.ToLower(ns.Ns))
+		}
+	}
+
+	if len(authoritativeNss) > 0 {
+		return authoritativeNss, nil
+	}
+	return nil, errors.New("could not determine authoritative nameservers")
+}
+
+// FindPrimaryNsByFqdn determines the primary nameserver of the zone apex for the given fqdn
+// by recursing up the domain labels until the nameserver returns a SOA record in the answer section.
+func FindPrimaryNsByFqdn(fqdn string) (string, error) {
+	return FindPrimaryNsByFqdnCustom(fqdn, recursiveNameservers)
+}
+
+// FindPrimaryNsByFqdnCustom determines the primary nameserver of the zone apex for the given fqdn
+// by recursing up the domain labels until the nameserver returns a SOA record in the answer section.
+func FindPrimaryNsByFqdnCustom(fqdn string, nameservers []string) (string, error) {
+	soa, err := lookupSoaByFqdn(fqdn, nameservers)
+	if err != nil {
+		return "", err
+	}
+	return soa.primaryNs, nil
+}
+
+// FindZoneByFqdn determines the zone apex for the given fqdn
+// by recursing up the domain labels until the nameserver returns a SOA record in the answer section.
+func FindZoneByFqdn(fqdn string) (string, error) {
+	return FindZoneByFqdnCustom(fqdn, recursiveNameservers)
+}
+
+// FindZoneByFqdnCustom determines the zone apex for the given fqdn
+// by recursing up the domain labels until the nameserver returns a SOA record in the answer section.
+func FindZoneByFqdnCustom(fqdn string, nameservers []string) (string, error) {
+	soa, err := lookupSoaByFqdn(fqdn, nameservers)
+	if err != nil {
+		return "", err
+	}
+	return soa.zone, nil
+}
+
+func lookupSoaByFqdn(fqdn string, nameservers []string) (*soaCacheEntry, error) {
+	muFqdnSoaCache.Lock()
+	defer muFqdnSoaCache.Unlock()
+
+	// Do we have it cached and is it still fresh?
+	if ent := fqdnSoaCache[fqdn]; ent != nil && !ent.isExpired() {
+		return ent, nil
+	}
+
+	ent, err := fetchSoaByFqdn(fqdn, nameservers)
+	if err != nil {
+		return nil, err
+	}
+
+	fqdnSoaCache[fqdn] = ent
+	return ent, nil
+}
+
+func fetchSoaByFqdn(fqdn string, nameservers []string) (*soaCacheEntry, error) {
+	var err error
+	var in *dns.Msg
+
+	labelIndexes := dns.Split(fqdn)
+	for _, index := range labelIndexes {
+		domain := fqdn[index:]
+
+		in, err = dnsQuery(domain, dns.TypeSOA, nameservers, true)
+		if err != nil {
+			continue
+		}
+
+		if in == nil {
+			continue
+		}
+
+		switch in.Rcode {
+		case dns.RcodeSuccess:
+			// Check if we got a SOA RR in the answer section
+			if len(in.Answer) == 0 {
+				continue
+			}
+
+			// CNAME records cannot/should not exist at the root of a zone.
+			// So we skip a domain when a CNAME is found.
+			if dnsMsgContainsCNAME(in) {
+				continue
+			}
+
+			for _, ans := range in.Answer {
+				if soa, ok := ans.(*dns.SOA); ok {
+					return newSoaCacheEntry(soa), nil
+				}
+			}
+		case dns.RcodeNameError:
+			// NXDOMAIN
+		default:
+			// Any response code other than NOERROR and NXDOMAIN is treated as error
+			return nil, fmt.Errorf("unexpected response code '%s' for %s", dns.RcodeToString[in.Rcode], domain)
+		}
+	}
+
+	return nil, fmt.Errorf("could not find the start of authority for %s%s", fqdn, formatDNSError(in, err))
+}
+
+// dnsMsgContainsCNAME checks for a CNAME answer in msg.
+func dnsMsgContainsCNAME(msg *dns.Msg) bool {
+	for _, ans := range msg.Answer {
+		if _, ok := ans.(*dns.CNAME); ok {
+			return true
+		}
+	}
+	return false
+}
+
+func dnsQuery(fqdn string, rtype uint16, nameservers []string, recursive bool) (*dns.Msg, error) {
+	m := createDNSMsg(fqdn, rtype, recursive)
+
+	var in *dns.Msg
+	var err error
+
+	for _, ns := range nameservers {
+		in, err = sendDNSQuery(m, ns)
+		if err == nil && len(in.Answer) > 0 {
+			break
+		}
+	}
+	return in, err
+}
+
+func createDNSMsg(fqdn string, rtype uint16, recursive bool) *dns.Msg {
+	m := new(dns.Msg)
+	m.SetQuestion(fqdn, rtype)
+	m.SetEdns0(4096, false)
+
+	if !recursive {
+		m.RecursionDesired = false
+	}
+
+	return m
+}
+
+func sendDNSQuery(m *dns.Msg, ns string) (*dns.Msg, error) {
+	if ok, _ := strconv.ParseBool(os.Getenv("LEGO_EXPERIMENTAL_DNS_TCP_ONLY")); ok {
+		tcp := &dns.Client{Net: "tcp", Timeout: dnsTimeout}
+		in, _, err := tcp.Exchange(m, ns)
+
+		return in, err
+	}
+
+	udp := &dns.Client{Net: "udp", Timeout: dnsTimeout}
+	in, _, err := udp.Exchange(m, ns)
+
+	if in != nil && in.Truncated {
+		tcp := &dns.Client{Net: "tcp", Timeout: dnsTimeout}
+		// If the TCP request succeeds, the err will reset to nil
+		in, _, err = tcp.Exchange(m, ns)
+	}
+
+	return in, err
+}
+
+func formatDNSError(msg *dns.Msg, err error) string {
+	var parts []string
+
+	if msg != nil {
+		parts = append(parts, dns.RcodeToString[msg.Rcode])
+	}
+
+	if err != nil {
+		parts = append(parts, err.Error())
+	}
+
+	if len(parts) > 0 {
+		return ": " + strings.Join(parts, " ")
+	}
+
+	return ""
+}

challenge/dns01/nameserver_test.go

@@ -0,0 +1,199 @@
+package dns01
+
+import (
+	"sort"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestLookupNameserversOK(t *testing.T) {
+	testCases := []struct {
+		fqdn string
+		nss  []string
+	}{
+		{
+			fqdn: "en.wikipedia.org.",
+			nss:  []string{"ns0.wikimedia.org.", "ns1.wikimedia.org.", "ns2.wikimedia.org."},
+		},
+		{
+			fqdn: "www.google.com.",
+			nss:  []string{"ns1.google.com.", "ns2.google.com.", "ns3.google.com.", "ns4.google.com."},
+		},
+		{
+			fqdn: "physics.georgetown.edu.",
+			nss:  []string{"ns4.georgetown.edu.", "ns5.georgetown.edu.", "ns6.georgetown.edu."},
+		},
+	}
+
+	for _, test := range testCases {
+		test := test
+		t.Run(test.fqdn, func(t *testing.T) {
+			t.Parallel()
+
+			nss, err := lookupNameservers(test.fqdn)
+			require.NoError(t, err)
+
+			sort.Strings(nss)
+			sort.Strings(test.nss)
+
+			assert.EqualValues(t, test.nss, nss)
+		})
+	}
+}
+
+func TestLookupNameserversErr(t *testing.T) {
+	testCases := []struct {
+		desc  string
+		fqdn  string
+		error string
+	}{
+		{
+			desc:  "invalid tld",
+			fqdn:  "_null.n0n0.",
+			error: "could not determine the zone",
+		},
+	}
+
+	for _, test := range testCases {
+		test := test
+		t.Run(test.desc, func(t *testing.T) {
+			t.Parallel()
+
+			_, err := lookupNameservers(test.fqdn)
+			require.Error(t, err)
+			assert.Contains(t, err.Error(), test.error)
+		})
+	}
+}
+
+var findXByFqdnTestCases = []struct {
+	desc          string
+	fqdn          string
+	zone          string
+	primaryNs     string
+	nameservers   []string
+	expectedError string
+}{
+	{
+		desc:        "domain is a CNAME",
+		fqdn:        "mail.google.com.",
+		zone:        "google.com.",
+		primaryNs:   "ns1.google.com.",
+		nameservers: recursiveNameservers,
+	},
+	{
+		desc:        "domain is a non-existent subdomain",
+		fqdn:        "foo.google.com.",
+		zone:        "google.com.",
+		primaryNs:   "ns1.google.com.",
+		nameservers: recursiveNameservers,
+	},
+	{
+		desc:        "domain is a eTLD",
+		fqdn:        "example.com.ac.",
+		zone:        "ac.",
+		primaryNs:   "a0.nic.ac.",
+		nameservers: recursiveNameservers,
+	},
+	{
+		desc:        "domain is a cross-zone CNAME",
+		fqdn:        "cross-zone-example.assets.sh.",
+		zone:        "assets.sh.",
+		primaryNs:   "gina.ns.cloudflare.com.",
+		nameservers: recursiveNameservers,
+	},
+	{
+		desc:          "NXDOMAIN",
+		fqdn:          "test.lego.zz.",
+		zone:          "lego.zz.",
+		nameservers:   []string{"8.8.8.8:53"},
+		expectedError: "could not find the start of authority for test.lego.zz.: NXDOMAIN",
+	},
+	{
+		desc:        "several non existent nameservers",
+		fqdn:        "mail.google.com.",
+		zone:        "google.com.",
+		primaryNs:   "ns1.google.com.",
+		nameservers: []string{":7053", ":8053", "8.8.8.8:53"},
+	},
+	{
+		desc:          "only non-existent nameservers",
+		fqdn:          "mail.google.com.",
+		zone:          "google.com.",
+		nameservers:   []string{":7053", ":8053", ":9053"},
+		expectedError: "could not find the start of authority for mail.google.com.: read udp",
+	},
+	{
+		desc:          "no nameservers",
+		fqdn:          "test.ldez.com.",
+		zone:          "ldez.com.",
+		nameservers:   []string{},
+		expectedError: "could not find the start of authority for test.ldez.com.",
+	},
+}
+
+func TestFindZoneByFqdnCustom(t *testing.T) {
+	for _, test := range findXByFqdnTestCases {
+		t.Run(test.desc, func(t *testing.T) {
+			ClearFqdnCache()
+
+			zone, err := FindZoneByFqdnCustom(test.fqdn, test.nameservers)
+			if test.expectedError != "" {
+				require.Error(t, err)
+				assert.Contains(t, err.Error(), test.expectedError)
+			} else {
+				require.NoError(t, err)
+				assert.Equal(t, test.zone, zone)
+			}
+		})
+	}
+}
+
+func TestFindPrimaryNsByFqdnCustom(t *testing.T) {
+	for _, test := range findXByFqdnTestCases {
+		t.Run(test.desc, func(t *testing.T) {
+			ClearFqdnCache()
+
+			ns, err := FindPrimaryNsByFqdnCustom(test.fqdn, test.nameservers)
+			if test.expectedError != "" {
+				require.Error(t, err)
+				assert.Contains(t, err.Error(), test.expectedError)
+			} else {
+				require.NoError(t, err)
+				assert.Equal(t, test.primaryNs, ns)
+			}
+		})
+	}
+}
+
+func TestResolveConfServers(t *testing.T) {
+	testCases := []struct {
+		fixture  string
+		expected []string
+		defaults []string
+	}{
+		{
+			fixture:  "fixtures/resolv.conf.1",
+			defaults: []string{"127.0.0.1:53"},
+			expected: []string{"10.200.3.249:53", "10.200.3.250:5353", "[2001:4860:4860::8844]:53", "[10.0.0.1]:5353"},
+		},
+		{
+			fixture:  "fixtures/resolv.conf.nonexistant",
+			defaults: []string{"127.0.0.1:53"},
+			expected: []string{"127.0.0.1:53"},
+		},
+	}
+
+	for _, test := range testCases {
+		t.Run(test.fixture, func(t *testing.T) {
+			result := getNameservers(test.fixture, test.defaults)
+
+			sort.Strings(result)
+			sort.Strings(test.expected)
+
+			assert.Equal(t, test.expected, result)
+		})
+	}
+}

challenge/dns01/nameserver_unix.go

@@ -0,0 +1,8 @@
+//go:build !windows
+
+package dns01
+
+import "time"
+
+// dnsTimeout is used to override the default DNS timeout of 10 seconds.
+var dnsTimeout = 10 * time.Second

challenge/dns01/nameserver_windows.go

@@ -0,0 +1,8 @@
+//go:build windows
+
+package dns01
+
+import "time"
+
+// dnsTimeout is used to override the default DNS timeout of 20 seconds.
+var dnsTimeout = 20 * time.Second

challenge/dns01/precheck.go

@@ -0,0 +1,110 @@
+package dns01
+
+import (
+	"fmt"
+	"net"
+	"strings"
+
+	"github.com/miekg/dns"
+)
+
+// PreCheckFunc checks DNS propagation before notifying ACME that the DNS challenge is ready.
+type PreCheckFunc func(fqdn, value string) (bool, error)
+
+// WrapPreCheckFunc wraps a PreCheckFunc in order to do extra operations before or after
+// the main check, put it in a loop, etc.
+type WrapPreCheckFunc func(domain, fqdn, value string, check PreCheckFunc) (bool, error)
+
+// WrapPreCheck Allow to define checks before notifying ACME that the DNS challenge is ready.
+func WrapPreCheck(wrap WrapPreCheckFunc) ChallengeOption {
+	return func(chlg *Challenge) error {
+		chlg.preCheck.checkFunc = wrap
+		return nil
+	}
+}
+
+func DisableCompletePropagationRequirement() ChallengeOption {
+	return func(chlg *Challenge) error {
+		chlg.preCheck.requireCompletePropagation = false
+		return nil
+	}
+}
+
+type preCheck struct {
+	// checks DNS propagation before notifying ACME that the DNS challenge is ready.
+	checkFunc WrapPreCheckFunc
+	// require the TXT record to be propagated to all authoritative name servers
+	requireCompletePropagation bool
+}
+
+func newPreCheck() preCheck {
+	return preCheck{
+		requireCompletePropagation: true,
+	}
+}
+
+func (p preCheck) call(domain, fqdn, value string) (bool, error) {
+	if p.checkFunc == nil {
+		return p.checkDNSPropagation(fqdn, value)
+	}
+
+	return p.checkFunc(domain, fqdn, value, p.checkDNSPropagation)
+}
+
+// checkDNSPropagation checks if the expected TXT record has been propagated to all authoritative nameservers.
+func (p preCheck) checkDNSPropagation(fqdn, value string) (bool, error) {
+	// Initial attempt to resolve at the recursive NS
+	r, err := dnsQuery(fqdn, dns.TypeTXT, recursiveNameservers, true)
+	if err != nil {
+		return false, err
+	}
+
+	if !p.requireCompletePropagation {
+		return true, nil
+	}
+
+	if r.Rcode == dns.RcodeSuccess {
+		fqdn = updateDomainWithCName(r, fqdn)
+	}
+
+	authoritativeNss, err := lookupNameservers(fqdn)
+	if err != nil {
+		return false, err
+	}
+
+	return checkAuthoritativeNss(fqdn, value, authoritativeNss)
+}
+
+// checkAuthoritativeNss queries each of the given nameservers for the expected TXT record.
+func checkAuthoritativeNss(fqdn, value string, nameservers []string) (bool, error) {
+	for _, ns := range nameservers {
+		r, err := dnsQuery(fqdn, dns.TypeTXT, []string{net.JoinHostPort(ns, "53")}, false)
+		if err != nil {
+			return false, err
+		}
+
+		if r.Rcode != dns.RcodeSuccess {
+			return false, fmt.Errorf("NS %s returned %s for %s", ns, dns.RcodeToString[r.Rcode], fqdn)
+		}
+
+		var records []string
+
+		var found bool
+		for _, rr := range r.Answer {
+			if txt, ok := rr.(*dns.TXT); ok {
+				record := strings.Join(txt.Txt, "")
+				records = append(records, record)
+				if record == value {
+					found = true
+					break
+				}
+			}
+		}
+
+		if !found {
+			return false, fmt.Errorf("NS %s did not return the expected TXT record [fqdn: %s, value: %s]: %s", ns, fqdn, value, strings.Join(records, " ,"))
+		}
+	}
+
+	return true, nil
+}

challenge/dns01/precheck_test.go

@@ -0,0 +1,117 @@
+package dns01
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestCheckDNSPropagation(t *testing.T) {
+	testCases := []struct {
+		desc        string
+		fqdn        string
+		value       string
+		expectError bool
+	}{
+		{
+			desc:  "success",
+			fqdn:  "postman-echo.com.",
+			value: "postman-domain-verification=c85de626cb79d941310696e06558e2e790223802f3697dfbdcaf65510152d52c",
+		},
+		{
+			desc:        "no TXT record",
+			fqdn:        "acme-staging.api.letsencrypt.org.",
+			value:       "fe01=",
+			expectError: true,
+		},
+	}
+
+	for _, test := range testCases {
+		test := test
+		t.Run(test.desc, func(t *testing.T) {
+			t.Parallel()
+			ClearFqdnCache()
+
+			check := newPreCheck()
+
+			ok, err := check.checkDNSPropagation(test.fqdn, test.value)
+			if test.expectError {
+				assert.Errorf(t, err, "PreCheckDNS must failed for %s", test.fqdn)
+				assert.False(t, ok, "PreCheckDNS must failed for %s", test.fqdn)
+			} else {
+				assert.NoErrorf(t, err, "PreCheckDNS failed for %s", test.fqdn)
+				assert.True(t, ok, "PreCheckDNS failed for %s", test.fqdn)
+			}
+		})
+	}
+}
+
+func TestCheckAuthoritativeNss(t *testing.T) {
+	testCases := []struct {
+		desc        string
+		fqdn, value string
+		ns          []string
+		expected    bool
+	}{
+		{
+			desc:     "TXT RR w/ expected value",
+			fqdn:     "8.8.8.8.asn.routeviews.org.",
+			value:    "151698.8.8.024",
+			ns:       []string{"asnums.routeviews.org."},
+			expected: true,
+		},
+		{
+			desc: "No TXT RR",
+			fqdn: "ns1.google.com.",
+			ns:   []string{"ns2.google.com."},
+		},
+	}
+
+	for _, test := range testCases {
+		test := test
+		t.Run(test.desc, func(t *testing.T) {
+			t.Parallel()
+			ClearFqdnCache()
+
+			ok, _ := checkAuthoritativeNss(test.fqdn, test.value, test.ns)
+			assert.Equal(t, test.expected, ok, test.fqdn)
+		})
+	}
+}
+
+func TestCheckAuthoritativeNssErr(t *testing.T) {
+	testCases := []struct {
+		desc        string
+		fqdn, value string
+		ns          []string
+		error       string
+	}{
+		{
+			desc:  "TXT RR /w unexpected value",
+			fqdn:  "8.8.8.8.asn.routeviews.org.",
+			value: "fe01=",
+			ns:    []string{"asnums.routeviews.org."},
+			error: "did not return the expected TXT record",
+		},
+		{
+			desc:  "No TXT RR",
+			fqdn:  "ns1.google.com.",
+			value: "fe01=",
+			ns:    []string{"ns2.google.com."},
+			error: "did not return the expected TXT record",
+		},
+	}
+
+	for _, test := range testCases {
+		test := test
+		t.Run(test.desc, func(t *testing.T) {
+			t.Parallel()
+			ClearFqdnCache()
+
+			_, err := checkAuthoritativeNss(test.fqdn, test.value, test.ns)
+			require.Error(t, err)
+			assert.Contains(t, err.Error(), test.error)
+		})
+	}
+}

challenge/http01/domain_matcher.go

@@ -0,0 +1,187 @@
+package http01
+
+import (
+	"fmt"
+	"net/http"
+	"strings"
+)
+
+// A domainMatcher tries to match a domain (the one we're requesting a certificate for)
+// in the HTTP request coming from the ACME validation servers.
+// This step is part of DNS rebind attack prevention,
+// where the webserver matches incoming requests to a list of domain the server acts authoritative for.
+//
+// The most simple check involves finding the domain in the HTTP Host header;
+// this is what hostMatcher does.
+// Use it, when the http01.ProviderServer is directly reachable from the internet,
+// or when it operates behind a transparent proxy.
+//
+// In many (reverse) proxy setups, Apache and NGINX traditionally move the Host header to a new header named X-Forwarded-Host.
+// Use arbitraryMatcher("X-Forwarded-Host") in this case,
+// or the appropriate header name for other proxy servers.
+//
+// RFC7239 has standardized the different forwarding headers into a single header named Forwarded.
+// The header value has a different format, so you should use forwardedMatcher
+// when the http01.ProviderServer operates behind a RFC7239 compatible proxy.
+// https://www.rfc-editor.org/rfc/rfc7239.html
+//
+// Note: RFC7239 also reminds us, "that an HTTP list [...] may be split over multiple header fields" (section 7.1),
+// meaning that
+//
+//	X-Header: a
+//	X-Header: b
+//
+// is equal to
+//
+//	X-Header: a, b
+//
+// All matcher implementations (explicitly not excluding arbitraryMatcher!)
+// have in common that they only match against the first value in such lists.
+type domainMatcher interface {
+	// matches checks whether the request is valid for the given domain.
+	matches(request *http.Request, domain string) bool
+
+	// name returns the header name used in the check.
+	// This is primarily used to create meaningful error messages.
+	name() string
+}
+
+// hostMatcher checks whether (*net/http).Request.Host starts with a domain name.
+type hostMatcher struct{}
+
+func (m *hostMatcher) name() string {
+	return "Host"
+}
+
+func (m *hostMatcher) matches(r *http.Request, domain string) bool {
+	return strings.HasPrefix(r.Host, domain)
+}
+
+// hostMatcher checks whether the specified (*net/http.Request).Header value starts with a domain name.
+type arbitraryMatcher string
+
+func (m arbitraryMatcher) name() string {
+	return string(m)
+}
+
+func (m arbitraryMatcher) matches(r *http.Request, domain string) bool {
+	return strings.HasPrefix(r.Header.Get(m.name()), domain)
+}
+
+// forwardedMatcher checks whether the Forwarded header contains a "host" element starting with a domain name.
+// See https://www.rfc-editor.org/rfc/rfc7239.html for details.
+type forwardedMatcher struct{}
+
+func (m *forwardedMatcher) name() string {
+	return "Forwarded"
+}
+
+func (m *forwardedMatcher) matches(r *http.Request, domain string) bool {
+	fwds, err := parseForwardedHeader(r.Header.Get(m.name()))
+	if err != nil {
+		return false
+	}
+
+	if len(fwds) == 0 {
+		return false
+	}
+
+	host := fwds[0]["host"]
+	return strings.HasPrefix(host, domain)
+}
+
+// parsing requires some form of state machine.
+func parseForwardedHeader(s string) (elements []map[string]string, err error) {
+	cur := make(map[string]string)
+	key := ""
+	val := ""
+	inquote := false
+
+	pos := 0
+	l := len(s)
+	for i := 0; i < l; i++ {
+		r := rune(s[i])
+
+		if inquote {
+			if r == '"' {
+				cur[key] = s[pos:i]
+				key = ""
+				pos = i
+				inquote = false
+			}
+			continue
+		}
+
+		switch {
+		case r == '"': // start of quoted-string
+			if key == "" {
+				return nil, fmt.Errorf("unexpected quoted string as pos %d", i)
+			}
+			inquote = true
+			pos = i + 1
+
+		case r == ';': // end of forwarded-pair
+			cur[key] = s[pos:i]
+			key = ""
+			i = skipWS(s, i)
+			pos = i + 1
+
+		case r == '=': // end of token
+			key = strings.ToLower(strings.TrimFunc(s[pos:i], isWS))
+			i = skipWS(s, i)
+			pos = i + 1
+
+		case r == ',': // end of forwarded-element
+			if key != "" {
+				if val == "" {
+					val = s[pos:i]
+				}
+				cur[key] = val
+			}
+			elements = append(elements, cur)
+			cur = make(map[string]string)
+			key = ""
+			val = ""
+
+			i = skipWS(s, i)
+			pos = i + 1
+		case tchar(r) || isWS(r): // valid token character or whitespace
+			continue
+		default:
+			return nil, fmt.Errorf("invalid token character at pos %d: %c", i, r)
+		}
+	}
+
+	if inquote {
+		return nil, fmt.Errorf("unterminated quoted-string at pos %d", len(s))
+	}
+
+	if key != "" {
+		if pos < len(s) {
+			val = s[pos:]
+		}
+		cur[key] = val
+	}
+	if len(cur) > 0 {
+		elements = append(elements, cur)
+	}
+	return elements, nil
+}
+
+func tchar(r rune) bool {
+	return strings.ContainsRune("!#$%&'*+-.^_`|~", r) ||
+		'0' <= r && r <= '9' ||
+		'a' <= r && r <= 'z' ||
+		'A' <= r && r <= 'Z'
+}
+
+func skipWS(s string, i int) int {
+	for isWS(rune(s[i+1])) {
+		i++
+	}
+	return i
+}
+
+func isWS(r rune) bool {
+	return strings.ContainsRune(" \t\v\r\n", r)
+}

challenge/http01/domain_matcher_test.go

@@ -0,0 +1,86 @@
+package http01
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestParseForwardedHeader(t *testing.T) {
+	testCases := []struct {
+		name  string
+		input string
+		want  []map[string]string
+		err   string
+	}{
+		{
+			name:  "empty input",
+			input: "",
+			want:  nil,
+		},
+		{
+			name:  "simple case",
+			input: `for=1.2.3.4;host=example.com; by=127.0.0.1`,
+			want: []map[string]string{
+				{"for": "1.2.3.4", "host": "example.com", "by": "127.0.0.1"},
+			},
+		},
+		{
+			name:  "quoted-string",
+			input: `foo="bar"`,
+			want: []map[string]string{
+				{"foo": "bar"},
+			},
+		},
+		{
+			name:  "multiple entries",
+			input: `a=1, b=2; c=3, d=4`,
+			want: []map[string]string{
+				{"a": "1"},
+				{"b": "2", "c": "3"},
+				{"d": "4"},
+			},
+		},
+		{
+			name:  "whitespace",
+			input: "   a =  1,\tb\n=\r\n2,c=\"   untrimmed  \"",
+			want: []map[string]string{
+				{"a": "1"},
+				{"b": "2"},
+				{"c": "   untrimmed  "},
+			},
+		},
+		{
+			name:  "unterminated quote",
+			input: `x="y`,
+			err:   "unterminated quoted-string",
+		},
+		{
+			name:  "unexpected quote",
+			input: `"x=y"`,
+			err:   "unexpected quote",
+		},
+		{
+			name:  "invalid token",
+			input: `a=b, ipv6=[fe80::1], x=y`,
+			err:   "invalid token character at pos 10: [",
+		},
+	}
+
+	for _, test := range testCases {
+		test := test
+		t.Run(test.name, func(t *testing.T) {
+			t.Parallel()
+
+			actual, err := parseForwardedHeader(test.input)
+			if test.err == "" {
+				require.NoError(t, err)
+				assert.EqualValues(t, test.want, actual)
+			} else {
+				require.Error(t, err)
+				assert.Contains(t, err.Error(), test.err)
+			}
+		})
+	}
+}

challenge/http01/http_challenge.go

@@ -0,0 +1,65 @@
+package http01
+
+import (
+	"fmt"
+
+	"github.com/go-acme/lego/v4/acme"
+	"github.com/go-acme/lego/v4/acme/api"
+	"github.com/go-acme/lego/v4/challenge"
+	"github.com/go-acme/lego/v4/log"
+)
+
+type ValidateFunc func(core *api.Core, domain string, chlng acme.Challenge) error
+
+// ChallengePath returns the URL path for the `http-01` challenge.
+func ChallengePath(token string) string {
+	return "/.well-known/acme-challenge/" + token
+}
+
+type Challenge struct {
+	core     *api.Core
+	validate ValidateFunc
+	provider challenge.Provider
+}
+
+func NewChallenge(core *api.Core, validate ValidateFunc, provider challenge.Provider) *Challenge {
+	return &Challenge{
+		core:     core,
+		validate: validate,
+		provider: provider,
+	}
+}
+
+func (c *Challenge) SetProvider(provider challenge.Provider) {
+	c.provider = provider
+}
+
+func (c *Challenge) Solve(authz acme.Authorization) error {
+	domain := challenge.GetTargetedDomain(authz)
+	log.Infof("[%s] acme: Trying to solve HTTP-01", domain)
+
+	chlng, err := challenge.FindChallenge(challenge.HTTP01, authz)
+	if err != nil {
+		return err
+	}
+
+	// Generate the Key Authorization for the challenge
+	keyAuth, err := c.core.GetKeyAuthorization(chlng.Token)
+	if err != nil {
+		return err
+	}
+
+	err = c.provider.Present(authz.Identifier.Value, chlng.Token, keyAuth)
+	if err != nil {
+		return fmt.Errorf("[%s] acme: error presenting token: %w", domain, err)
+	}
+	defer func() {
+		err := c.provider.CleanUp(authz.Identifier.Value, chlng.Token, keyAuth)
+		if err != nil {
+			log.Warnf("[%s] acme: cleaning up failed: %v", domain, err)
+		}
+	}()
+
+	chlng.KeyAuthorization = keyAuth
+	return c.validate(c.core, domain, chlng)
+}

challenge/http01/http_challenge_server.go

@@ -0,0 +1,137 @@
+package http01
+
+import (
+	"fmt"
+	"io/fs"
+	"net"
+	"net/http"
+	"net/textproto"
+	"os"
+	"strings"
+
+	"github.com/go-acme/lego/v4/log"
+)
+
+// ProviderServer implements ChallengeProvider for `http-01` challenge.
+// It may be instantiated without using the NewProviderServer function if
+// you want only to use the default values.
+type ProviderServer struct {
+	address string
+	network string // must be valid argument to net.Listen
+
+	socketMode fs.FileMode
+
+	matcher  domainMatcher
+	done     chan bool
+	listener net.Listener
+}
+
+// NewProviderServer creates a new ProviderServer on the selected interface and port.
+// Setting iface and / or port to an empty string will make the server fall back to
+// the "any" interface and port 80 respectively.
+func NewProviderServer(iface, port string) *ProviderServer {
+	if port == "" {
+		port = "80"
+	}
+
+	return &ProviderServer{network: "tcp", address: net.JoinHostPort(iface, port), matcher: &hostMatcher{}}
+}
+
+func NewUnixProviderServer(socketPath string, mode fs.FileMode) *ProviderServer {
+	return &ProviderServer{network: "unix", address: socketPath, socketMode: mode, matcher: &hostMatcher{}}
+}
+
+// Present starts a web server and makes the token available at `ChallengePath(token)` for web requests.
+func (s *ProviderServer) Present(domain, token, keyAuth string) error {
+	var err error
+	s.listener, err = net.Listen(s.network, s.GetAddress())
+	if err != nil {
+		return fmt.Errorf("could not start HTTP server for challenge: %w", err)
+	}
+
+	if s.network == "unix" {
+		if err = os.Chmod(s.address, s.socketMode); err != nil {
+			return fmt.Errorf("chmod %s: %w", s.address, err)
+		}
+	}
+
+	s.done = make(chan bool)
+	go s.serve(domain, token, keyAuth)
+	return nil
+}
+
+func (s *ProviderServer) GetAddress() string {
+	return s.address
+}
+
+// CleanUp closes the HTTP server and removes the token from `ChallengePath(token)`.
+func (s *ProviderServer) CleanUp(domain, token, keyAuth string) error {
+	if s.listener == nil {
+		return nil
+	}
+	s.listener.Close()
+	<-s.done
+	return nil
+}
+
+// SetProxyHeader changes the validation of incoming requests.
+// By default, s matches the "Host" header value to the domain name.
+//
+// When the server runs behind a proxy server, this is not the correct place to look at;
+// Apache and NGINX have traditionally moved the original Host header into a new header named "X-Forwarded-Host".
+// Other webservers might use different names;
+// and RFC7239 has standardized a new header named "Forwarded" (with slightly different semantics).
+//
+// The exact behavior depends on the value of headerName:
+// - "" (the empty string) and "Host" will restore the default and only check the Host header
+// - "Forwarded" will look for a Forwarded header, and inspect it according to https://www.rfc-editor.org/rfc/rfc7239.html
+// - any other value will check the header value with the same name.
+func (s *ProviderServer) SetProxyHeader(headerName string) {
+	switch h := textproto.CanonicalMIMEHeaderKey(headerName); h {
+	case "", "Host":
+		s.matcher = &hostMatcher{}
+	case "Forwarded":
+		s.matcher = &forwardedMatcher{}
+	default:
+		s.matcher = arbitraryMatcher(h)
+	}
+}
+
+func (s *ProviderServer) serve(domain, token, keyAuth string) {
+	path := ChallengePath(token)
+
+	// The incoming request will be validated to prevent DNS rebind attacks.
+	// We only respond with the keyAuth, when we're receiving a GET requests with
+	// the "Host" header matching the domain (the latter is configurable though SetProxyHeader).
+	mux := http.NewServeMux()
+	mux.HandleFunc(path, func(w http.ResponseWriter, r *http.Request) {
+		if r.Method == http.MethodGet && s.matcher.matches(r, domain) {
+			w.Header().Set("Content-Type", "text/plain")
+			_, err := w.Write([]byte(keyAuth))
+			if err != nil {
+				http.Error(w, err.Error(), http.StatusInternalServerError)
+				return
+			}
+			log.Infof("[%s] Served key authentication", domain)
+		} else {
+			log.Warnf("Received request for domain %s with method %s but the domain did not match any challenge. Please ensure you are passing the %s header properly.", r.Host, r.Method, s.matcher.name())
+			_, err := w.Write([]byte("TEST"))
+			if err != nil {
+				http.Error(w, err.Error(), http.StatusInternalServerError)
+				return
+			}
+		}
+	})
+
+	httpServer := &http.Server{Handler: mux}
+
+	// Once httpServer is shut down
+	// we don't want any lingering connections, so disable KeepAlives.
+	httpServer.SetKeepAlivesEnabled(false)
+
+	err := httpServer.Serve(s.listener)
+	if err != nil && !strings.Contains(err.Error(), "use of closed network connection") {
+		log.Println(err)
+	}
+	s.done <- true
+}

challenge/http01/http_challenge_test.go

@@ -0,0 +1,438 @@
+package http01
+
+import (
+	"context"
+	"crypto/rand"
+	"crypto/rsa"
+	"fmt"
+	"io"
+	"io/fs"
+	"net"
+	"net/http"
+	"net/textproto"
+	"os"
+	"path/filepath"
+	"runtime"
+	"testing"
+
+	"github.com/go-acme/lego/v4/acme"
+	"github.com/go-acme/lego/v4/acme/api"
+	"github.com/go-acme/lego/v4/challenge"
+	"github.com/go-acme/lego/v4/platform/tester"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestProviderServer_GetAddress(t *testing.T) {
+	dir := t.TempDir()
+	t.Cleanup(func() { _ = os.RemoveAll(dir) })
+
+	sock := filepath.Join(dir, "var", "run", "test")
+
+	testCases := []struct {
+		desc     string
+		server   *ProviderServer
+		expected string
+	}{
+		{
+			desc:     "TCP default address",
+			server:   NewProviderServer("", ""),
+			expected: ":80",
+		},
+		{
+			desc:     "TCP with explicit port",
+			server:   NewProviderServer("", "8080"),
+			expected: ":8080",
+		},
+		{
+			desc:     "TCP with host and port",
+			server:   NewProviderServer("localhost", "8080"),
+			expected: "localhost:8080",
+		},
+		{
+			desc:     "UDS socket",
+			server:   NewUnixProviderServer(sock, fs.ModeSocket|0o666),
+			expected: sock,
+		},
+	}
+
+	for _, test := range testCases {
+		test := test
+		t.Run(test.desc, func(t *testing.T) {
+			t.Parallel()
+
+			address := test.server.GetAddress()
+			assert.Equal(t, test.expected, address)
+		})
+	}
+}
+
+func TestChallenge(t *testing.T) {
+	_, apiURL := tester.SetupFakeAPI(t)
+
+	providerServer := NewProviderServer("", "23457")
+
+	validate := func(_ *api.Core, _ string, chlng acme.Challenge) error {
+		uri := "http://localhost" + providerServer.GetAddress() + ChallengePath(chlng.Token)
+
+		resp, err := http.DefaultClient.Get(uri)
+		if err != nil {
+			return err
+		}
+		defer resp.Body.Close()
+
+		if want := "text/plain"; resp.Header.Get("Content-Type") != want {
+			t.Errorf("Get(%q) Content-Type: got %q, want %q", uri, resp.Header.Get("Content-Type"), want)
+		}
+
+		body, err := io.ReadAll(resp.Body)
+		if err != nil {
+			return err
+		}
+		bodyStr := string(body)
+
+		if bodyStr != chlng.KeyAuthorization {
+			t.Errorf("Get(%q) Body: got %q, want %q", uri, bodyStr, chlng.KeyAuthorization)
+		}
+
+		return nil
+	}
+
+	privateKey, err := rsa.GenerateKey(rand.Reader, 512)
+	require.NoError(t, err, "Could not generate test key")
+
+	core, err := api.New(http.DefaultClient, "lego-test", apiURL+"/dir", "", privateKey)
+	require.NoError(t, err)
+
+	solver := NewChallenge(core, validate, providerServer)
+
+	authz := acme.Authorization{
+		Identifier: acme.Identifier{
+			Value: "localhost:23457",
+		},
+		Challenges: []acme.Challenge{
+			{Type: challenge.HTTP01.String(), Token: "http1"},
+		},
+	}
+
+	err = solver.Solve(authz)
+	require.NoError(t, err)
+}
+
+func TestChallengeUnix(t *testing.T) {
+	if runtime.GOOS != "linux" {
+		t.Skip("only for UNIX systems")
+	}
+
+	_, apiURL := tester.SetupFakeAPI(t)
+
+	dir := t.TempDir()
+	t.Cleanup(func() { _ = os.RemoveAll(dir) })
+
+	socket := filepath.Join(dir, "lego-challenge-test.sock")
+
+	providerServer := NewUnixProviderServer(socket, fs.ModeSocket|0o666)
+
+	validate := func(_ *api.Core, _ string, chlng acme.Challenge) error {
+		// any uri will do, as we hijack the dial
+		uri := "http://localhost" + ChallengePath(chlng.Token)
+
+		client := &http.Client{Transport: &http.Transport{
+			DialContext: func(ctx context.Context, network, addr string) (net.Conn, error) {
+				return net.Dial("unix", socket)
+			},
+		}}
+
+		resp, err := client.Get(uri)
+		if err != nil {
+			return err
+		}
+
+		defer resp.Body.Close()
+
+		if want := "text/plain"; resp.Header.Get("Content-Type") != want {
+			t.Errorf("Get(%q) Content-Type: got %q, want %q", uri, resp.Header.Get("Content-Type"), want)
+		}
+
+		body, err := io.ReadAll(resp.Body)
+		if err != nil {
+			return err
+		}
+		bodyStr := string(body)
+
+		if bodyStr != chlng.KeyAuthorization {
+			t.Errorf("Get(%q) Body: got %q, want %q", uri, bodyStr, chlng.KeyAuthorization)
+		}
+
+		return nil
+	}
+
+	privateKey, err := rsa.GenerateKey(rand.Reader, 512)
+	require.NoError(t, err, "Could not generate test key")
+
+	core, err := api.New(http.DefaultClient, "lego-test", apiURL+"/dir", "", privateKey)
+	require.NoError(t, err)
+
+	solver := NewChallenge(core, validate, providerServer)
+
+	authz := acme.Authorization{
+		Identifier: acme.Identifier{
+			Value: "localhost",
+		},
+		Challenges: []acme.Challenge{
+			{Type: challenge.HTTP01.String(), Token: "http1"},
+		},
+	}
+
+	err = solver.Solve(authz)
+	require.NoError(t, err)
+}
+
+func TestChallengeInvalidPort(t *testing.T) {
+	_, apiURL := tester.SetupFakeAPI(t)
+
+	privateKey, err := rsa.GenerateKey(rand.Reader, 128)
+	require.NoError(t, err, "Could not generate test key")
+
+	core, err := api.New(http.DefaultClient, "lego-test", apiURL+"/dir", "", privateKey)
+	require.NoError(t, err)
+
+	validate := func(_ *api.Core, _ string, _ acme.Challenge) error { return nil }
+
+	solver := NewChallenge(core, validate, NewProviderServer("", "123456"))
+
+	authz := acme.Authorization{
+		Identifier: acme.Identifier{
+			Value: "localhost:123456",
+		},
+		Challenges: []acme.Challenge{
+			{Type: challenge.HTTP01.String(), Token: "http2"},
+		},
+	}
+
+	err = solver.Solve(authz)
+	require.Error(t, err)
+	assert.Contains(t, err.Error(), "invalid port")
+	assert.Contains(t, err.Error(), "123456")
+}
+
+type testProxyHeader struct {
+	name   string
+	values []string
+}
+
+func (h *testProxyHeader) update(r *http.Request) {
+	if h == nil || len(h.values) == 0 {
+		return
+	}
+	if h.name == "Host" {
+		r.Host = h.values[0]
+	} else if h.name != "" {
+		r.Header[h.name] = h.values
+	}
+}
+
+func TestChallengeWithProxy(t *testing.T) {
+	h := func(name string, values ...string) *testProxyHeader {
+		name = textproto.CanonicalMIMEHeaderKey(name)
+		return &testProxyHeader{name, values}
+	}
+
+	const (
+		ok   = "localhost:23457"
+		nook = "example.com"
+	)
+
+	testCases := []struct {
+		name   string
+		header *testProxyHeader
+		extra  *testProxyHeader
+		isErr  bool
+	}{
+		// tests for hostMatcher
+		{
+			name: "no proxy",
+		},
+		{
+			name:   "empty string",
+			header: h(""),
+		},
+		{
+			name:   "empty Host",
+			header: h("host"),
+		},
+		{
+			name:   "matching Host",
+			header: h("host", ok),
+		},
+		{
+			name:   "Host mismatch",
+			header: h("host", nook),
+			isErr:  true,
+		},
+		{
+			name:   "Host mismatch (ignoring forwarding header)",
+			header: h("host", nook),
+			extra:  h("X-Forwarded-Host", ok),
+			isErr:  true,
+		},
+		// test for arbitraryMatcher
+		{
+			name:   "matching X-Forwarded-Host",
+			header: h("X-Forwarded-Host", ok),
+		},
+		{
+			name:   "matching X-Forwarded-Host (multiple fields)",
+			header: h("X-Forwarded-Host", ok, nook),
+		},
+		{
+			name:   "matching X-Forwarded-Host (chain value)",
+			header: h("X-Forwarded-Host", ok+", "+nook),
+		},
+		{
+			name:   "X-Forwarded-Host mismatch",
+			header: h("X-Forwarded-Host", nook),
+			extra:  h("host", ok),
+			isErr:  true,
+		},
+		{
+			name:   "X-Forwarded-Host mismatch (multiple fields)",
+			header: h("X-Forwarded-Host", nook, ok),
+			isErr:  true,
+		},
+		{
+			name:   "matching X-Something-Else",
+			header: h("X-Something-Else", ok),
+		},
+		{
+			name:   "matching X-Something-Else (multiple fields)",
+			header: h("X-Something-Else", ok, nook),
+		},
+		{
+			name:   "matching X-Something-Else (chain value)",
+			header: h("X-Something-Else", ok+", "+nook),
+		},
+		{
+			name:   "X-Something-Else mismatch",
+			header: h("X-Something-Else", nook),
+			isErr:  true,
+		},
+		{
+			name:   "X-Something-Else mismatch (multiple fields)",
+			header: h("X-Something-Else", nook, ok),
+			isErr:  true,
+		},
+		{
+			name:   "X-Something-Else mismatch (chain value)",
+			header: h("X-Something-Else", nook+", "+ok),
+			isErr:  true,
+		},
+		// tests for forwardedHeader
+		{
+			name:   "matching Forwarded",
+			header: h("Forwarded", fmt.Sprintf("host=%q;foo=bar", ok)),
+		},
+		{
+			name:   "matching Forwarded (multiple fields)",
+			header: h("Forwarded", fmt.Sprintf("host=%q", ok), "host="+nook),
+		},
+		{
+			name:   "matching Forwarded (chain value)",
+			header: h("Forwarded", fmt.Sprintf("host=%q, host=%s", ok, nook)),
+		},
+		{
+			name:   "Forwarded mismatch",
+			header: h("Forwarded", "host="+nook),
+			isErr:  true,
+		},
+		{
+			name:   "Forwarded mismatch (missing information)",
+			header: h("Forwarded", "for=127.0.0.1"),
+			isErr:  true,
+		},
+		{
+			name:   "Forwarded mismatch (multiple fields)",
+			header: h("Forwarded", "host="+nook, fmt.Sprintf("host=%q", ok)),
+			isErr:  true,
+		},
+		{
+			name:   "Forwarded mismatch (chain value)",
+			header: h("Forwarded", fmt.Sprintf("host=%s, host=%q", nook, ok)),
+			isErr:  true,
+		},
+	}
+
+	for _, test := range testCases {
+		t.Run(test.name, func(t *testing.T) {
+			testServeWithProxy(t, test.header, test.extra, test.isErr)
+		})
+	}
+}
+
+func testServeWithProxy(t *testing.T, header, extra *testProxyHeader, expectError bool) {
+	t.Helper()
+
+	_, apiURL := tester.SetupFakeAPI(t)
+
+	providerServer := NewProviderServer("localhost", "23457")
+	if header != nil {
+		providerServer.SetProxyHeader(header.name)
+	}
+
+	validate := func(_ *api.Core, _ string, chlng acme.Challenge) error {
+		uri := "http://" + providerServer.GetAddress() + ChallengePath(chlng.Token)
+
+		req, err := http.NewRequest(http.MethodGet, uri, nil)
+		if err != nil {
+			return err
+		}
+		header.update(req)
+		extra.update(req)
+
+		resp, err := http.DefaultClient.Do(req)
+		if err != nil {
+			return err
+		}
+		defer resp.Body.Close()
+
+		if want := "text/plain"; resp.Header.Get("Content-Type") != want {
+			return fmt.Errorf("Get(%q) Content-Type: got %q, want %q", uri, resp.Header.Get("Content-Type"), want)
+		}
+
+		body, err := io.ReadAll(resp.Body)
+		if err != nil {
+			return err
+		}
+		bodyStr := string(body)
+
+		if bodyStr != chlng.KeyAuthorization {
+			return fmt.Errorf("Get(%q) Body: got %q, want %q", uri, bodyStr, chlng.KeyAuthorization)
+		}
+
+		return nil
+	}
+
+	privateKey, err := rsa.GenerateKey(rand.Reader, 512)
+	require.NoError(t, err, "Could not generate test key")
+
+	core, err := api.New(http.DefaultClient, "lego-test", apiURL+"/dir", "", privateKey)
+	require.NoError(t, err)
+
+	solver := NewChallenge(core, validate, providerServer)
+
+	authz := acme.Authorization{
+		Identifier: acme.Identifier{
+			Value: "localhost:23457",
+		},
+		Challenges: []acme.Challenge{
+			{Type: challenge.HTTP01.String(), Token: "http1"},
+		},
+	}
+
+	err = solver.Solve(authz)
+	if expectError {
+		require.Error(t, err)
+	} else {
+		require.NoError(t, err)
+	}
+}

challenge/nns01/nns_challenge.go

@@ -0,0 +1,125 @@
+package nns01
+
+import (
+	"crypto/sha256"
+	"encoding/base64"
+	"fmt"
+	"time"
+
+	"github.com/go-acme/lego/v4/acme"
+	"github.com/go-acme/lego/v4/acme/api"
+	"github.com/go-acme/lego/v4/challenge"
+	"github.com/go-acme/lego/v4/log"
+)
+
+type ValidateFunc func(core *api.Core, domain string, chlng acme.Challenge) error
+
+// Challenge implements the nns-01 challenge.
+type Challenge struct {
+	core     *api.Core
+	validate ValidateFunc
+	provider challenge.Provider
+}
+
+func NewChallenge(core *api.Core, validate ValidateFunc, provider challenge.Provider) *Challenge {
+	chlg := &Challenge{
+		core:     core,
+		validate: validate,
+		provider: provider,
+	}
+
+	return chlg
+}
+
+// PreSolve submits the txt record to the nns provider.
+func (c *Challenge) PreSolve(authz acme.Authorization) error {
+	domain := challenge.GetTargetedDomain(authz)
+	log.Infof("[%s] acme: Preparing to solve NNS-01", domain)
+
+	chlng, keyAuth, err := c.getChallengeInfo(authz)
+	if err != nil {
+		return err
+	}
+
+	err = c.provider.Present(authz.Identifier.Value, chlng.Token, keyAuth)
+	if err != nil {
+		return fmt.Errorf("[%s] acme: error presenting token: %w", domain, err)
+	}
+
+	return nil
+}
+
+func (c *Challenge) Solve(authz acme.Authorization) error {
+	domain := challenge.GetTargetedDomain(authz)
+	log.Infof("[%s] acme: Trying to solve NNS-01", domain)
+
+	chlng, keyAuth, err := c.getChallengeInfo(authz)
+	if err != nil {
+		return err
+	}
+
+	chlng.KeyAuthorization = keyAuth
+	return c.validate(c.core, domain, chlng)
+}
+
+// CleanUp cleans the challenge.
+func (c *Challenge) CleanUp(authz acme.Authorization) error {
+	log.Infof("[%s] acme: Cleaning NNS-01 challenge", challenge.GetTargetedDomain(authz))
+
+	chlng, keyAuth, err := c.getChallengeInfo(authz)
+	if err != nil {
+		return err
+	}
+
+	return c.provider.CleanUp(authz.Identifier.Value, chlng.Token, keyAuth)
+}
+
+func (c *Challenge) Sequential() (bool, time.Duration) {
+	if p, ok := c.provider.(sequential); ok {
+		return ok, p.Sequential()
+	}
+	return false, 0
+}
+
+type sequential interface {
+	Sequential() time.Duration
+}
+
+// RecordInfo contains the information use to create the TXT record.
+type RecordInfo struct {
+	// FQDN is the full-qualified challenge domain (`acme-challenge.[domain]`)
+	FQDN string
+	// Value contains the value for the TXT record
+	Value string
+}
+
+// GetRecordInfo returns information used to create a TXT record which will fulfill the `nns-01` challenge.
+func GetRecordInfo(domain, keyAuth string) RecordInfo {
+	keyAuthShaBytes := sha256.Sum256([]byte(keyAuth))
+	// base64URL encoding without padding
+	value := base64.RawURLEncoding.EncodeToString(keyAuthShaBytes[:sha256.Size])
+
+	return RecordInfo{
+		Value: value,
+		FQDN:  getRecordFQDN(domain),
+	}
+}
+
+func getRecordFQDN(domain string) string {
+	return fmt.Sprintf("acme-challenge.%s", domain)
+}
+
+func (c *Challenge) getChallengeInfo(authz acme.Authorization) (acme.Challenge, string, error) {
+	chlng, err := challenge.FindChallenge(challenge.NNS01, authz)
+	if err != nil {
+		return acme.Challenge{}, "", err
+	}
+
+	// Generate the Key Authorization for the challenge
+	keyAuth, err := c.core.GetKeyAuthorization(chlng.Token)
+	if err != nil {
+		return acme.Challenge{}, "", err
+	}
+
+	return chlng, keyAuth, nil
+}

challenge/nns01/nns_provider.go

@@ -0,0 +1,171 @@
+package nns01
+
+import (
+	"context"
+	"fmt"
+	"net/url"
+
+	"git.frostfs.info/TrueCloudLab/frostfs-contract/nns"
+	"github.com/nspcc-dev/neo-go/cli/flags"
+	"github.com/nspcc-dev/neo-go/pkg/core/state"
+	"github.com/nspcc-dev/neo-go/pkg/rpcclient"
+	"github.com/nspcc-dev/neo-go/pkg/rpcclient/actor"
+	"github.com/nspcc-dev/neo-go/pkg/util"
+	"github.com/nspcc-dev/neo-go/pkg/wallet"
+)
+
+// multiSchemeClient unites invoker.RPCInvoke and common interface of
+// rpcclient.Client and rpcclient.WSClient.
+type multiSchemeClient interface {
+	actor.RPCActor
+	actor.RPCPollingWaiter
+	// Init turns client to "ready-to-work" state.
+	Init() error
+	// Close closes connections.
+	Close()
+	// GetContractStateByID returns state of the NNS contract on 1 input.
+	GetContractStateByID(int32) (*state.Contract, error)
+}
+
+type NNSProvider struct {
+	nnsServer   string
+	account     *wallet.Account
+	nnsContract util.Uint160
+	client      multiSchemeClient
+}
+
+// NewNNSProvider returns configured NNSProvider instance.
+func NewNNSProvider(nnsServer string, walletFile string, accountAddress string, accountPassword string) (*NNSProvider, error) {
+	w, err := wallet.NewWalletFromFile(walletFile)
+	if err != nil {
+		return nil, fmt.Errorf("retrieve wallet from file: %w", err)
+	}
+	var address util.Uint160
+	if len(accountAddress) == 0 {
+		address = w.GetChangeAddress()
+	} else {
+		address, err = flags.ParseAddress(accountAddress)
+		if err != nil {
+			return nil, fmt.Errorf("parse account address: %w", err)
+		}
+	}
+	acc := w.GetAccount(address)
+	err = acc.Decrypt(accountPassword, w.Scrypt)
+	if err != nil {
+		return nil, fmt.Errorf("decrypt account: %w", err)
+	}
+
+	provider := NNSProvider{
+		nnsServer: nnsServer,
+		account:   acc,
+	}
+	return &provider, nil
+}
+
+// dial connects to the address of the NNS server.
+// If URL address scheme is 'ws' or 'wss', then WebSocket protocol is used, otherwise HTTP.
+func (n *NNSProvider) dial() error {
+	var err error
+
+	uri, err := url.Parse(n.nnsServer)
+	if err == nil && (uri.Scheme == "ws" || uri.Scheme == "wss") {
+		// WSOptions not in package `github.com/nspcc-dev/neo-go v0.101.3`
+		n.client, err = rpcclient.NewWS(context.Background(), n.nnsServer, rpcclient.Options{})
+		if err != nil {
+			return fmt.Errorf("create Neo WebSocket client: %w", err)
+		}
+	} else {
+		n.client, err = rpcclient.New(context.Background(), n.nnsServer, rpcclient.Options{})
+		if err != nil {
+			return fmt.Errorf("create Neo HTTP client: %w", err)
+		}
+	}
+
+	if err = n.client.Init(); err != nil {
+		return fmt.Errorf("initialize Neo client: %w", err)
+	}
+
+	nnsContract, err := n.client.GetContractStateByID(1)
+	if err != nil {
+		return fmt.Errorf("get NNS contract state: %w", err)
+	}
+
+	n.nnsContract = nnsContract.Hash
+
+	return nil
+}
+
+// Close closes connections of multiSchemeClient.
+func (n *NNSProvider) close() {
+	if n.client != nil {
+		n.client.Close()
+	}
+}
+
+// Present creates a TXT record using the specified parameters to fulfill the nns-01 challenge.
+// It implements Provider interface in order to use NNSProvider as Provider.
+func (n *NNSProvider) Present(domain, _, keyAuth string) error {
+	err := n.dial()
+	if err != nil {
+		return fmt.Errorf("connect to the NNS server: %w", err)
+	}
+
+	act, err := actor.NewSimple(n.client, n.account)
+	if err != nil {
+		return fmt.Errorf("create actor: %w", err)
+	}
+
+	info := GetRecordInfo(domain, keyAuth)
+	err = n.addTXTRecord(act, info.FQDN, info.Value)
+	if err != nil {
+		return fmt.Errorf("add txt record: %w", err)
+	}
+	return nil
+}
+
+// addTXTRecord adds a new TXT record with the specified data to the provided domain by calling `addRecord` method
+// of NNS contract.
+func (n *NNSProvider) addTXTRecord(act *actor.Actor, name string, data string) error {
+	waiter, err := actor.NewPollingWaiter(n.client)
+	if err != nil {
+		return fmt.Errorf("waiter creation: %w", err)
+	}
+	_, err = waiter.Wait(act.SendCall(n.nnsContract, "addRecord", name, int64(nns.TXT), data))
+	if err != nil {
+		return fmt.Errorf("contract invocation: %w", err)
+	}
+
+	return nil
+}
+
+// CleanUp removes the TXT record matching the specified parameters.
+// It implements Provider interface in order to use NNSProvider as Provider.
+func (n *NNSProvider) CleanUp(domain, _, keyAuth string) error {
+	defer n.close()
+
+	act, err := actor.NewSimple(n.client, n.account)
+	if err != nil {
+		return fmt.Errorf("create actor: %w", err)
+	}
+
+	info := GetRecordInfo(domain, keyAuth)
+	err = n.deleteTXTRecords(act, info.FQDN)
+	if err != nil {
+		return fmt.Errorf("delete txt records: %w", err)
+	}
+	return nil
+}
+
+// deleteTXTRecords removes TXT records from the provided domain by calling `deleteRecords` method of NNS contract.
+func (n *NNSProvider) deleteTXTRecords(act *actor.Actor, name string) error {
+	waiter, err := actor.NewPollingWaiter(n.client)
+	if err != nil {
+		return fmt.Errorf("waiter creation: %w", err)
+	}
+	_, err = waiter.Wait(act.SendCall(n.nnsContract, "deleteRecords", name, int64(nns.TXT)))
+	if err != nil {
+		return fmt.Errorf("contract invocation: %w", err)
+	}
+
+	return nil
+}

challenge/provider.go

@@ -0,0 +1,28 @@
+package challenge
+
+import "time"
+
+// Provider enables implementing a custom challenge
+// provider. Present presents the solution to a challenge available to
+// be solved. CleanUp will be called by the challenge if Present ends
+// in a non-error state.
+type Provider interface {
+	Present(domain, token, keyAuth string) error
+	CleanUp(domain, token, keyAuth string) error
+}
+
+// ProviderTimeout allows for implementing a
+// Provider where an unusually long timeout is required when
+// waiting for an ACME challenge to be satisfied, such as when
+// checking for DNS record propagation. If an implementor of a
+// Provider provides a Timeout method, then the return values
+// of the Timeout method will be used when appropriate by the acme
+// package. The interval value is the time between checks.
+//
+// The default values used for timeout and interval are 60 seconds and
+// 2 seconds respectively. These are used when no Timeout method is
+// defined for the Provider.
+type ProviderTimeout interface {
+	Provider
+	Timeout() (timeout, interval time.Duration)
+}

challenge/resolver/errors.go

@@ -0,0 +1,25 @@
+package resolver
+
+import (
+	"bytes"
+	"fmt"
+	"sort"
+)
+
+// obtainError is returned when there are specific errors available per domain.
+type obtainError map[string]error
+
+func (e obtainError) Error() string {
+	buffer := bytes.NewBufferString("error: one or more domains had a problem:\n")
+
+	var domains []string
+	for domain := range e {
+		domains = append(domains, domain)
+	}
+	sort.Strings(domains)
+
+	for _, domain := range domains {
+		_, _ = fmt.Fprintf(buffer, "[%s] %s\n", domain, e[domain])
+	}
+	return buffer.String()
+}

challenge/resolver/prober.go

@@ -0,0 +1,173 @@
+package resolver
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/go-acme/lego/v4/acme"
+	"github.com/go-acme/lego/v4/challenge"
+	"github.com/go-acme/lego/v4/log"
+)
+
+// Interface for all challenge solvers to implement.
+type solver interface {
+	Solve(authorization acme.Authorization) error
+}
+
+// Interface for challenges like dns, where we can set a record in advance for ALL challenges.
+// This saves quite a bit of time vs creating the records and solving them serially.
+type preSolver interface {
+	PreSolve(authorization acme.Authorization) error
+}
+
+// Interface for challenges like dns, where we can solve all the challenges before to delete them.
+type cleanup interface {
+	CleanUp(authorization acme.Authorization) error
+}
+
+type sequential interface {
+	Sequential() (bool, time.Duration)
+}
+
+// an authz with the solver we have chosen and the index of the challenge associated with it.
+type selectedAuthSolver struct {
+	authz  acme.Authorization
+	solver solver
+}
+
+type Prober struct {
+	solverManager *SolverManager
+}
+
+func NewProber(solverManager *SolverManager) *Prober {
+	return &Prober{
+		solverManager: solverManager,
+	}
+}
+
+// Solve Looks through the challenge combinations to find a solvable match.
+// Then solves the challenges in series and returns.
+func (p *Prober) Solve(authorizations []acme.Authorization) error {
+	failures := make(obtainError)
+
+	var authSolvers []*selectedAuthSolver
+	var authSolversSequential []*selectedAuthSolver
+
+	// Loop through the resources, basically through the domains.
+	// First pass just selects a solver for each authz.
+	for _, authz := range authorizations {
+		domain := challenge.GetTargetedDomain(authz)
+		if authz.Status == acme.StatusValid {
+			// Boulder might recycle recent validated authz (see issue #267)
+			log.Infof("[%s] acme: authorization already valid; skipping challenge", domain)
+			continue
+		}
+
+		if solvr := p.solverManager.chooseSolver(authz); solvr != nil {
+			authSolver := &selectedAuthSolver{authz: authz, solver: solvr}
+
+			switch s := solvr.(type) {
+			case sequential:
+				if ok, _ := s.Sequential(); ok {
+					authSolversSequential = append(authSolversSequential, authSolver)
+				} else {
+					authSolvers = append(authSolvers, authSolver)
+				}
+			default:
+				authSolvers = append(authSolvers, authSolver)
+			}
+		} else {
+			failures[domain] = fmt.Errorf("[%s] acme: could not determine solvers", domain)
+		}
+	}
+
+	parallelSolve(authSolvers, failures)
+
+	sequentialSolve(authSolversSequential, failures)
+
+	// Be careful not to return an empty failures map,
+	// for even an empty obtainError is a non-nil error value
+	if len(failures) > 0 {
+		return failures
+	}
+	return nil
+}
+
+func sequentialSolve(authSolvers []*selectedAuthSolver, failures obtainError) {
+	for i, authSolver := range authSolvers {
+		// Submit the challenge
+		domain := challenge.GetTargetedDomain(authSolver.authz)
+
+		if solvr, ok := authSolver.solver.(preSolver); ok {
+			err := solvr.PreSolve(authSolver.authz)
+			if err != nil {
+				failures[domain] = err
+				cleanUp(authSolver.solver, authSolver.authz)
+				continue
+			}
+		}
+
+		// Solve challenge
+		err := authSolver.solver.Solve(authSolver.authz)
+		if err != nil {
+			failures[domain] = err
+			cleanUp(authSolver.solver, authSolver.authz)
+			continue
+		}
+
+		// Clean challenge
+		cleanUp(authSolver.solver, authSolver.authz)
+
+		if len(authSolvers)-1 > i {
+			solvr := authSolver.solver.(sequential)
+			_, interval := solvr.Sequential()
+			log.Infof("sequence: wait for %s", interval)
+			time.Sleep(interval)
+		}
+	}
+}
+
+func parallelSolve(authSolvers []*selectedAuthSolver, failures obtainError) {
+	// For all valid preSolvers, first submit the challenges so they have max time to propagate
+	for _, authSolver := range authSolvers {
+		authz := authSolver.authz
+		if solvr, ok := authSolver.solver.(preSolver); ok {
+			err := solvr.PreSolve(authz)
+			if err != nil {
+				failures[challenge.GetTargetedDomain(authz)] = err
+			}
+		}
+	}
+
+	defer func() {
+		// Clean all created TXT records
+		for _, authSolver := range authSolvers {
+			cleanUp(authSolver.solver, authSolver.authz)
+		}
+	}()
+
+	// Finally solve all challenges for real
+	for _, authSolver := range authSolvers {
+		authz := authSolver.authz
+		domain := challenge.GetTargetedDomain(authz)
+		if failures[domain] != nil {
+			// already failed in previous loop
+			continue
+		}
+
+		err := authSolver.solver.Solve(authz)
+		if err != nil {
+			failures[domain] = err
+		}
+	}
+}
+
+func cleanUp(solvr solver, authz acme.Authorization) {
+	if solvr, ok := solvr.(cleanup); ok {
+		domain := challenge.GetTargetedDomain(authz)
+		err := solvr.CleanUp(authz)
+		if err != nil {
+			log.Warnf("[%s] acme: cleaning up failed: %v ", domain, err)
+		}
+	}
+}

challenge/resolver/prober_mock_test.go

@@ -0,0 +1,44 @@
+package resolver
+
+import (
+	"time"
+
+	"github.com/go-acme/lego/v4/acme"
+	"github.com/go-acme/lego/v4/challenge"
+)
+
+type preSolverMock struct {
+	preSolve map[string]error
+	solve    map[string]error
+	cleanUp  map[string]error
+}
+
+func (s *preSolverMock) PreSolve(authorization acme.Authorization) error {
+	return s.preSolve[authorization.Identifier.Value]
+}
+
+func (s *preSolverMock) Solve(authorization acme.Authorization) error {
+	return s.solve[authorization.Identifier.Value]
+}
+
+func (s *preSolverMock) CleanUp(authorization acme.Authorization) error {
+	return s.cleanUp[authorization.Identifier.Value]
+}
+
+func createStubAuthorizationHTTP01(domain, status string) acme.Authorization {
+	return acme.Authorization{
+		Status:  status,
+		Expires: time.Now(),
+		Identifier: acme.Identifier{
+			Type:  challenge.HTTP01.String(),
+			Value: domain,
+		},
+		Challenges: []acme.Challenge{
+			{
+				Type:      challenge.HTTP01.String(),
+				Validated: time.Now(),
+				Error:     nil,
+			},
+		},
+	}
+}

challenge/resolver/prober_test.go

@@ -0,0 +1,118 @@
+package resolver
+
+import (
+	"errors"
+	"testing"
+
+	"github.com/go-acme/lego/v4/acme"
+	"github.com/go-acme/lego/v4/challenge"
+	"github.com/stretchr/testify/require"
+)
+
+func TestProber_Solve(t *testing.T) {
+	testCases := []struct {
+		desc          string
+		solvers       map[challenge.Type]solver
+		authz         []acme.Authorization
+		expectedError string
+	}{
+		{
+			desc: "success",
+			solvers: map[challenge.Type]solver{
+				challenge.HTTP01: &preSolverMock{
+					preSolve: map[string]error{},
+					solve:    map[string]error{},
+					cleanUp:  map[string]error{},
+				},
+			},
+			authz: []acme.Authorization{
+				createStubAuthorizationHTTP01("acme.wtf", acme.StatusProcessing),
+				createStubAuthorizationHTTP01("lego.wtf", acme.StatusProcessing),
+				createStubAuthorizationHTTP01("mydomain.wtf", acme.StatusProcessing),
+			},
+		},
+		{
+			desc: "already valid",
+			solvers: map[challenge.Type]solver{
+				challenge.HTTP01: &preSolverMock{
+					preSolve: map[string]error{},
+					solve:    map[string]error{},
+					cleanUp:  map[string]error{},
+				},
+			},
+			authz: []acme.Authorization{
+				createStubAuthorizationHTTP01("acme.wtf", acme.StatusValid),
+				createStubAuthorizationHTTP01("lego.wtf", acme.StatusValid),
+				createStubAuthorizationHTTP01("mydomain.wtf", acme.StatusValid),
+			},
+		},
+		{
+			desc: "when preSolve fail, auth is flagged as error and skipped",
+			solvers: map[challenge.Type]solver{
+				challenge.HTTP01: &preSolverMock{
+					preSolve: map[string]error{
+						"acme.wtf": errors.New("preSolve error acme.wtf"),
+					},
+					solve: map[string]error{
+						"acme.wtf": errors.New("solve error acme.wtf"),
+					},
+					cleanUp: map[string]error{
+						"acme.wtf": errors.New("clean error acme.wtf"),
+					},
+				},
+			},
+			authz: []acme.Authorization{
+				createStubAuthorizationHTTP01("acme.wtf", acme.StatusProcessing),
+				createStubAuthorizationHTTP01("lego.wtf", acme.StatusProcessing),
+				createStubAuthorizationHTTP01("mydomain.wtf", acme.StatusProcessing),
+			},
+			expectedError: `error: one or more domains had a problem:
+[acme.wtf] preSolve error acme.wtf
+`,
+		},
+		{
+			desc: "errors at different stages",
+			solvers: map[challenge.Type]solver{
+				challenge.HTTP01: &preSolverMock{
+					preSolve: map[string]error{
+						"acme.wtf": errors.New("preSolve error acme.wtf"),
+					},
+					solve: map[string]error{
+						"acme.wtf": errors.New("solve error acme.wtf"),
+						"lego.wtf": errors.New("solve error lego.wtf"),
+					},
+					cleanUp: map[string]error{
+						"mydomain.wtf": errors.New("clean error mydomain.wtf"),
+					},
+				},
+			},
+			authz: []acme.Authorization{
+				createStubAuthorizationHTTP01("acme.wtf", acme.StatusProcessing),
+				createStubAuthorizationHTTP01("lego.wtf", acme.StatusProcessing),
+				createStubAuthorizationHTTP01("mydomain.wtf", acme.StatusProcessing),
+			},
+			expectedError: `error: one or more domains had a problem:
+[acme.wtf] preSolve error acme.wtf
+[lego.wtf] solve error lego.wtf
+`,
+		},
+	}
+
+	for _, test := range testCases {
+		test := test
+		t.Run(test.desc, func(t *testing.T) {
+			t.Parallel()
+
+			prober := &Prober{
+				solverManager: &SolverManager{solvers: test.solvers},
+			}
+
+			err := prober.Solve(test.authz)
+			if test.expectedError != "" {
+				require.EqualError(t, err, test.expectedError)
+			} else {
+				require.NoError(t, err)
+			}
+		})
+	}
+}

challenge/resolver/solver_manager.go

@@ -0,0 +1,171 @@
+package resolver
+
+import (
+	"errors"
+	"fmt"
+	"sort"
+	"strconv"
+	"time"
+
+	"github.com/cenkalti/backoff/v4"
+	"github.com/go-acme/lego/v4/acme"
+	"github.com/go-acme/lego/v4/acme/api"
+	"github.com/go-acme/lego/v4/challenge"
+	"github.com/go-acme/lego/v4/challenge/dns01"
+	"github.com/go-acme/lego/v4/challenge/http01"
+	"github.com/go-acme/lego/v4/challenge/nns01"
+	"github.com/go-acme/lego/v4/challenge/tlsalpn01"
+	"github.com/go-acme/lego/v4/log"
+)
+
+type byType []acme.Challenge
+
+func (a byType) Len() int           { return len(a) }
+func (a byType) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }
+func (a byType) Less(i, j int) bool { return a[i].Type > a[j].Type }
+
+type SolverManager struct {
+	core    *api.Core
+	solvers map[challenge.Type]solver
+}
+
+func NewSolversManager(core *api.Core) *SolverManager {
+	return &SolverManager{
+		solvers: map[challenge.Type]solver{},
+		core:    core,
+	}
+}
+
+// SetHTTP01Provider specifies a custom provider p that can solve the given HTTP-01 challenge.
+func (c *SolverManager) SetHTTP01Provider(p challenge.Provider) error {
+	c.solvers[challenge.HTTP01] = http01.NewChallenge(c.core, validate, p)
+	return nil
+}
+
+// SetTLSALPN01Provider specifies a custom provider p that can solve the given TLS-ALPN-01 challenge.
+func (c *SolverManager) SetTLSALPN01Provider(p challenge.Provider) error {
+	c.solvers[challenge.TLSALPN01] = tlsalpn01.NewChallenge(c.core, validate, p)
+	return nil
+}
+
+// SetDNS01Provider specifies a custom provider p that can solve the given DNS-01 challenge.
+func (c *SolverManager) SetDNS01Provider(p challenge.Provider, opts ...dns01.ChallengeOption) error {
+	c.solvers[challenge.DNS01] = dns01.NewChallenge(c.core, validate, p, opts...)
+	return nil
+}
+
+// SetNNS01Provider specifies a custom provider p that can solve the given NNS-01 challenge.
+func (c *SolverManager) SetNNS01Provider(p challenge.Provider) error {
+	c.solvers[challenge.NNS01] = nns01.NewChallenge(c.core, validate, p)
+	return nil
+}
+
+// Remove removes a challenge type from the available solvers.
+func (c *SolverManager) Remove(chlgType challenge.Type) {
+	delete(c.solvers, chlgType)
+}
+
+// Checks all challenges from the server in order and returns the first matching solver.
+func (c *SolverManager) chooseSolver(authz acme.Authorization) solver {
+	// Allow to have a deterministic challenge order
+	sort.Sort(byType(authz.Challenges))
+
+	domain := challenge.GetTargetedDomain(authz)
+	for _, chlg := range authz.Challenges {
+		if solvr, ok := c.solvers[challenge.Type(chlg.Type)]; ok {
+			log.Infof("[%s] acme: use %s solver", domain, chlg.Type)
+			return solvr
+		}
+		log.Infof("[%s] acme: Could not find solver for: %s", domain, chlg.Type)
+	}
+
+	return nil
+}
+
+func validate(core *api.Core, domain string, chlg acme.Challenge) error {
+	chlng, err := core.Challenges.New(chlg.URL)
+	if err != nil {
+		return fmt.Errorf("failed to initiate challenge: %w", err)
+	}
+
+	valid, err := checkChallengeStatus(chlng)
+	if err != nil {
+		return err
+	}
+
+	if valid {
+		log.Infof("[%s] The server validated our request", domain)
+		return nil
+	}
+
+	ra, err := strconv.Atoi(chlng.RetryAfter)
+	if err != nil {
+		// The ACME server MUST return a Retry-After.
+		// If it doesn't, we'll just poll hard.
+		// Boulder does not implement the ability to retry challenges or the Retry-After header.
+		// https://github.com/letsencrypt/boulder/blob/master/docs/acme-divergences.md#section-82
+		ra = 5
+	}
+	initialInterval := time.Duration(ra) * time.Second
+
+	bo := backoff.NewExponentialBackOff()
+	bo.InitialInterval = initialInterval
+	bo.MaxInterval = 10 * initialInterval
+	bo.MaxElapsedTime = 100 * initialInterval
+
+	// After the path is sent, the ACME server will access our server.
+	// Repeatedly check the server for an updated status on our request.
+	operation := func() error {
+		authz, err := core.Authorizations.Get(chlng.AuthorizationURL)
+		if err != nil {
+			return backoff.Permanent(err)
+		}
+
+		valid, err := checkAuthorizationStatus(authz)
+		if err != nil {
+			return backoff.Permanent(err)
+		}
+
+		if valid {
+			log.Infof("[%s] The server validated our request", domain)
+			return nil
+		}
+
+		return errors.New("the server didn't respond to our request")
+	}
+
+	return backoff.Retry(operation, bo)
+}
+
+func checkChallengeStatus(chlng acme.ExtendedChallenge) (bool, error) {
+	switch chlng.Status {
+	case acme.StatusValid:
+		return true, nil
+	case acme.StatusPending, acme.StatusProcessing:
+		return false, nil
+	case acme.StatusInvalid:
+		return false, chlng.Error
+	default:
+		return false, errors.New("the server returned an unexpected state")
+	}
+}
+
+func checkAuthorizationStatus(authz acme.Authorization) (bool, error) {
+	switch authz.Status {
+	case acme.StatusValid:
+		return true, nil
+	case acme.StatusPending, acme.StatusProcessing:
+		return false, nil
+	case acme.StatusDeactivated, acme.StatusExpired, acme.StatusRevoked:
+		return false, fmt.Errorf("the authorization state %s", authz.Status)
+	case acme.StatusInvalid:
+		for _, chlg := range authz.Challenges {
+			if chlg.Status == acme.StatusInvalid && chlg.Error != nil {
+				return false, chlg.Error
+			}
+		}
+		return false, fmt.Errorf("the authorization state %s", authz.Status)
+	default:
+		return false, errors.New("the server returned an unexpected state")
+	}
+}

challenge/resolver/solver_manager_test.go

@@ -0,0 +1,178 @@
+package resolver
+
+import (
+	"crypto/rand"
+	"crypto/rsa"
+	"fmt"
+	"io"
+	"net/http"
+	"sort"
+	"testing"
+
+	"github.com/go-acme/lego/v4/acme"
+	"github.com/go-acme/lego/v4/acme/api"
+	"github.com/go-acme/lego/v4/platform/tester"
+	"github.com/go-jose/go-jose/v3"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestByType(t *testing.T) {
+	challenges := []acme.Challenge{
+		{Type: "dns-01"}, {Type: "tlsalpn-01"}, {Type: "http-01"},
+	}
+
+	sort.Sort(byType(challenges))
+
+	expected := []acme.Challenge{
+		{Type: "tlsalpn-01"}, {Type: "http-01"}, {Type: "dns-01"},
+	}
+
+	assert.Equal(t, expected, challenges)
+}
+
+func TestValidate(t *testing.T) {
+	mux, apiURL := tester.SetupFakeAPI(t)
+
+	var statuses []string
+
+	privateKey, _ := rsa.GenerateKey(rand.Reader, 512)
+
+	mux.HandleFunc("/chlg", func(w http.ResponseWriter, r *http.Request) {
+		if r.Method != http.MethodPost {
+			http.Error(w, http.StatusText(http.StatusMethodNotAllowed), http.StatusMethodNotAllowed)
+			return
+		}
+
+		if err := validateNoBody(privateKey, r); err != nil {
+			http.Error(w, err.Error(), http.StatusBadRequest)
+			return
+		}
+
+		w.Header().Set("Link", "<"+apiURL+`/my-authz>; rel="up"`)
+
+		st := statuses[0]
+		statuses = statuses[1:]
+
+		chlg := &acme.Challenge{Type: "http-01", Status: st, URL: "http://example.com/", Token: "token"}
+		if st == acme.StatusInvalid {
+			chlg.Error = &acme.ProblemDetails{}
+		}
+
+		err := tester.WriteJSONResponse(w, chlg)
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+	})
+
+	mux.HandleFunc("/my-authz", func(w http.ResponseWriter, r *http.Request) {
+		if r.Method != http.MethodPost {
+			http.Error(w, http.StatusText(http.StatusMethodNotAllowed), http.StatusMethodNotAllowed)
+			return
+		}
+
+		st := statuses[0]
+		statuses = statuses[1:]
+
+		authorization := acme.Authorization{
+			Status:     st,
+			Challenges: []acme.Challenge{},
+		}
+
+		if st == acme.StatusInvalid {
+			chlg := acme.Challenge{
+				Status: acme.StatusInvalid,
+				Error:  &acme.ProblemDetails{},
+			}
+			authorization.Challenges = append(authorization.Challenges, chlg)
+		}
+
+		err := tester.WriteJSONResponse(w, authorization)
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+	})
+
+	core, err := api.New(http.DefaultClient, "lego-test", apiURL+"/dir", "", privateKey)
+	require.NoError(t, err)
+
+	testCases := []struct {
+		name     string
+		statuses []string
+		want     string
+	}{
+		{
+			name:     "POST-unexpected",
+			statuses: []string{"weird"},
+			want:     "unexpected",
+		},
+		{
+			name:     "POST-valid",
+			statuses: []string{acme.StatusValid},
+		},
+		{
+			name:     "POST-invalid",
+			statuses: []string{acme.StatusInvalid},
+			want:     "error",
+		},
+		{
+			name:     "POST-pending-unexpected",
+			statuses: []string{acme.StatusPending, "weird"},
+			want:     "unexpected",
+		},
+		{
+			name:     "POST-pending-valid",
+			statuses: []string{acme.StatusPending, acme.StatusValid},
+		},
+		{
+			name:     "POST-pending-invalid",
+			statuses: []string{acme.StatusPending, acme.StatusInvalid},
+			want:     "error",
+		},
+	}
+
+	for _, test := range testCases {
+		t.Run(test.name, func(t *testing.T) {
+			statuses = test.statuses
+
+			err := validate(core, "example.com", acme.Challenge{Type: "http-01", Token: "token", URL: apiURL + "/chlg"})
+			if test.want == "" {
+				require.NoError(t, err)
+			} else {
+				require.Error(t, err)
+				assert.Contains(t, err.Error(), test.want)
+			}
+		})
+	}
+}
+
+// validateNoBody reads the http.Request POST body, parses the JWS and validates it to read the body.
+// If there is an error doing this,
+// or if the JWS body is not the empty JSON payload "{}" or a POST-as-GET payload "" an error is returned.
+// We use this to verify challenge POSTs to the ts below do not send a JWS body.
+func validateNoBody(privateKey *rsa.PrivateKey, r *http.Request) error {
+	reqBody, err := io.ReadAll(r.Body)
+	if err != nil {
+		return err
+	}
+
+	jws, err := jose.ParseSigned(string(reqBody))
+	if err != nil {
+		return err
+	}
+
+	body, err := jws.Verify(&jose.JSONWebKey{
+		Key:       privateKey.Public(),
+		Algorithm: "RSA",
+	})
+	if err != nil {
+		return err
+	}
+
+	if bodyStr := string(body); bodyStr != "{}" && bodyStr != "" {
+		return fmt.Errorf(`expected JWS POST body "{}" or "", got %q`, bodyStr)
+	}
+	return nil
+}

challenge/tlsalpn01/tls_alpn_challenge.go

@@ -0,0 +1,129 @@
+package tlsalpn01
+
+import (
+	"crypto/rsa"
+	"crypto/sha256"
+	"crypto/tls"
+	"crypto/x509/pkix"
+	"encoding/asn1"
+	"fmt"
+
+	"github.com/go-acme/lego/v4/acme"
+	"github.com/go-acme/lego/v4/acme/api"
+	"github.com/go-acme/lego/v4/certcrypto"
+	"github.com/go-acme/lego/v4/challenge"
+	"github.com/go-acme/lego/v4/log"
+)
+
+// idPeAcmeIdentifierV1 is the SMI Security for PKIX Certification Extension OID referencing the ACME extension.
+// Reference: https://www.rfc-editor.org/rfc/rfc8737.html#section-6.1
+var idPeAcmeIdentifierV1 = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 1, 31}
+
+type ValidateFunc func(core *api.Core, domain string, chlng acme.Challenge) error
+
+type Challenge struct {
+	core     *api.Core
+	validate ValidateFunc
+	provider challenge.Provider
+}
+
+func NewChallenge(core *api.Core, validate ValidateFunc, provider challenge.Provider) *Challenge {
+	return &Challenge{
+		core:     core,
+		validate: validate,
+		provider: provider,
+	}
+}
+
+func (c *Challenge) SetProvider(provider challenge.Provider) {
+	c.provider = provider
+}
+
+// Solve manages the provider to validate and solve the challenge.
+func (c *Challenge) Solve(authz acme.Authorization) error {
+	domain := authz.Identifier.Value
+	log.Infof("[%s] acme: Trying to solve TLS-ALPN-01", challenge.GetTargetedDomain(authz))
+
+	chlng, err := challenge.FindChallenge(challenge.TLSALPN01, authz)
+	if err != nil {
+		return err
+	}
+
+	// Generate the Key Authorization for the challenge
+	keyAuth, err := c.core.GetKeyAuthorization(chlng.Token)
+	if err != nil {
+		return err
+	}
+
+	err = c.provider.Present(domain, chlng.Token, keyAuth)
+	if err != nil {
+		return fmt.Errorf("[%s] acme: error presenting token: %w", challenge.GetTargetedDomain(authz), err)
+	}
+	defer func() {
+		err := c.provider.CleanUp(domain, chlng.Token, keyAuth)
+		if err != nil {
+			log.Warnf("[%s] acme: cleaning up failed: %v", challenge.GetTargetedDomain(authz), err)
+		}
+	}()
+
+	chlng.KeyAuthorization = keyAuth
+	return c.validate(c.core, domain, chlng)
+}
+
+// ChallengeBlocks returns PEM blocks (certPEMBlock, keyPEMBlock) with the acmeValidation-v1 extension
+// and domain name for the `tls-alpn-01` challenge.
+func ChallengeBlocks(domain, keyAuth string) ([]byte, []byte, error) {
+	// Compute the SHA-256 digest of the key authorization.
+	zBytes := sha256.Sum256([]byte(keyAuth))
+
+	value, err := asn1.Marshal(zBytes[:sha256.Size])
+	if err != nil {
+		return nil, nil, err
+	}
+
+	// Add the keyAuth digest as the acmeValidation-v1 extension
+	// (marked as critical such that it won't be used by non-ACME software).
+	// Reference: https://www.rfc-editor.org/rfc/rfc8737.html#section-3
+	extensions := []pkix.Extension{
+		{
+			Id:       idPeAcmeIdentifierV1,
+			Critical: true,
+			Value:    value,
+		},
+	}
+
+	// Generate a new RSA key for the certificates.
+	tempPrivateKey, err := certcrypto.GeneratePrivateKey(certcrypto.RSA2048)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	rsaPrivateKey := tempPrivateKey.(*rsa.PrivateKey)
+
+	// Generate the PEM certificate using the provided private key, domain, and extra extensions.
+	tempCertPEM, err := certcrypto.GeneratePemCert(rsaPrivateKey, domain, extensions)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	// Encode the private key into a PEM format. We'll need to use it to generate the x509 keypair.
+	rsaPrivatePEM := certcrypto.PEMEncode(rsaPrivateKey)
+
+	return tempCertPEM, rsaPrivatePEM, nil
+}
+
+// ChallengeCert returns a certificate with the acmeValidation-v1 extension
+// and domain name for the `tls-alpn-01` challenge.
+func ChallengeCert(domain, keyAuth string) (*tls.Certificate, error) {
+	tempCertPEM, rsaPrivatePEM, err := ChallengeBlocks(domain, keyAuth)
+	if err != nil {
+		return nil, err
+	}
+
+	cert, err := tls.X509KeyPair(tempCertPEM, rsaPrivatePEM)
+	if err != nil {
+		return nil, err
+	}
+
+	return &cert, nil
+}

challenge/tlsalpn01/tls_alpn_challenge_server.go

@@ -0,0 +1,96 @@
+package tlsalpn01
+
+import (
+	"crypto/tls"
+	"errors"
+	"fmt"
+	"net"
+	"net/http"
+	"strings"
+
+	"github.com/go-acme/lego/v4/log"
+)
+
+const (
+	// ACMETLS1Protocol is the ALPN Protocol ID for the ACME-TLS/1 Protocol.
+	ACMETLS1Protocol = "acme-tls/1"
+
+	// defaultTLSPort is the port that the ProviderServer will default to
+	// when no other port is provided.
+	defaultTLSPort = "443"
+)
+
+// ProviderServer implements ChallengeProvider for `TLS-ALPN-01` challenge.
+// It may be instantiated without using the NewProviderServer
+// if you want only to use the default values.
+type ProviderServer struct {
+	iface    string
+	port     string
+	listener net.Listener
+}
+
+// NewProviderServer creates a new ProviderServer on the selected interface and port.
+// Setting iface and / or port to an empty string will make the server fall back to
+// the "any" interface and port 443 respectively.
+func NewProviderServer(iface, port string) *ProviderServer {
+	return &ProviderServer{iface: iface, port: port}
+}
+
+func (s *ProviderServer) GetAddress() string {
+	return net.JoinHostPort(s.iface, s.port)
+}
+
+// Present generates a certificate with a SHA-256 digest of the keyAuth provided
+// as the acmeValidation-v1 extension value to conform to the ACME-TLS-ALPN spec.
+func (s *ProviderServer) Present(domain, token, keyAuth string) error {
+	if s.port == "" {
+		// Fallback to port 443 if the port was not provided.
+		s.port = defaultTLSPort
+	}
+
+	// Generate the challenge certificate using the provided keyAuth and domain.
+	cert, err := ChallengeCert(domain, keyAuth)
+	if err != nil {
+		return err
+	}
+
+	// Place the generated certificate with the extension into the TLS config
+	// so that it can serve the correct details.
+	tlsConf := new(tls.Config)
+	tlsConf.Certificates = []tls.Certificate{*cert}
+
+	// We must set that the `acme-tls/1` application level protocol is supported
+	// so that the protocol negotiation can succeed. Reference:
+	// https://www.rfc-editor.org/rfc/rfc8737.html#section-6.2
+	tlsConf.NextProtos = []string{ACMETLS1Protocol}
+
+	// Create the listener with the created tls.Config.
+	s.listener, err = tls.Listen("tcp", s.GetAddress(), tlsConf)
+	if err != nil {
+		return fmt.Errorf("could not start HTTPS server for challenge: %w", err)
+	}
+
+	// Shut the server down when we're finished.
+	go func() {
+		err := http.Serve(s.listener, nil)
+		if err != nil && !strings.Contains(err.Error(), "use of closed network connection") {
+			log.Println(err)
+		}
+	}()
+
+	return nil
+}
+
+// CleanUp closes the HTTPS server.
+func (s *ProviderServer) CleanUp(domain, token, keyAuth string) error {
+	if s.listener == nil {
+		return nil
+	}
+
+	// Server was created, close it.
+	if err := s.listener.Close(); err != nil && errors.Is(err, http.ErrServerClosed) {
+		return err
+	}
+
+	return nil
+}

challenge/tlsalpn01/tls_alpn_challenge_test.go

@@ -0,0 +1,193 @@
+package tlsalpn01
+
+import (
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/sha256"
+	"crypto/subtle"
+	"crypto/tls"
+	"encoding/asn1"
+	"net"
+	"net/http"
+	"testing"
+
+	"github.com/go-acme/lego/v4/acme"
+	"github.com/go-acme/lego/v4/acme/api"
+	"github.com/go-acme/lego/v4/challenge"
+	"github.com/go-acme/lego/v4/platform/tester"
+	"github.com/miekg/dns"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestChallenge(t *testing.T) {
+	_, apiURL := tester.SetupFakeAPI(t)
+
+	domain := "localhost"
+	port := "23457"
+
+	mockValidate := func(_ *api.Core, _ string, chlng acme.Challenge) error {
+		conn, err := tls.Dial("tcp", net.JoinHostPort(domain, port), &tls.Config{
+			ServerName:         domain,
+			InsecureSkipVerify: true,
+		})
+		require.NoError(t, err, "Expected to connect to challenge server without an error")
+
+		// Expect the server to only return one certificate
+		connState := conn.ConnectionState()
+		assert.Len(t, connState.PeerCertificates, 1, "Expected the challenge server to return exactly one certificate")
+
+		remoteCert := connState.PeerCertificates[0]
+		assert.Len(t, remoteCert.DNSNames, 1, "Expected the challenge certificate to have exactly one DNSNames entry")
+		assert.Equal(t, domain, remoteCert.DNSNames[0], "challenge certificate DNSName ")
+		assert.NotEmpty(t, remoteCert.Extensions, "Expected the challenge certificate to contain extensions")
+
+		idx := -1
+		for i, ext := range remoteCert.Extensions {
+			if idPeAcmeIdentifierV1.Equal(ext.Id) {
+				idx = i
+				break
+			}
+		}
+
+		require.NotEqual(t, -1, idx, "Expected the challenge certificate to contain an extension with the id-pe-acmeIdentifier id,")
+
+		ext := remoteCert.Extensions[idx]
+		assert.True(t, ext.Critical, "Expected the challenge certificate id-pe-acmeIdentifier extension to be marked as critical")
+
+		zBytes := sha256.Sum256([]byte(chlng.KeyAuthorization))
+		value, err := asn1.Marshal(zBytes[:sha256.Size])
+		require.NoError(t, err, "Expected marshaling of the keyAuth to return no error")
+
+		if subtle.ConstantTimeCompare(value, ext.Value) != 1 {
+			t.Errorf("Expected the challenge certificate id-pe-acmeIdentifier extension to contain the SHA-256 digest of the keyAuth, %v, but was %v", zBytes[:], ext.Value)
+		}
+
+		return nil
+	}
+
+	privateKey, err := rsa.GenerateKey(rand.Reader, 512)
+	require.NoError(t, err, "Could not generate test key")
+
+	core, err := api.New(http.DefaultClient, "lego-test", apiURL+"/dir", "", privateKey)
+	require.NoError(t, err)
+
+	solver := NewChallenge(
+		core,
+		mockValidate,
+		&ProviderServer{port: "23457"},
+	)
+
+	authz := acme.Authorization{
+		Identifier: acme.Identifier{
+			Type:  "dns",
+			Value: domain,
+		},
+		Challenges: []acme.Challenge{
+			{Type: challenge.TLSALPN01.String(), Token: "tlsalpn1"},
+		},
+	}
+
+	err = solver.Solve(authz)
+	require.NoError(t, err)
+}
+
+func TestChallengeInvalidPort(t *testing.T) {
+	_, apiURL := tester.SetupFakeAPI(t)
+
+	privateKey, err := rsa.GenerateKey(rand.Reader, 128)
+	require.NoError(t, err, "Could not generate test key")
+
+	core, err := api.New(http.DefaultClient, "lego-test", apiURL+"/dir", "", privateKey)
+	require.NoError(t, err)
+
+	solver := NewChallenge(
+		core,
+		func(_ *api.Core, _ string, _ acme.Challenge) error { return nil },
+		&ProviderServer{port: "123456"},
+	)
+
+	authz := acme.Authorization{
+		Identifier: acme.Identifier{
+			Value: "localhost:123456",
+		},
+		Challenges: []acme.Challenge{
+			{Type: challenge.TLSALPN01.String(), Token: "tlsalpn1"},
+		},
+	}
+
+	err = solver.Solve(authz)
+	require.Error(t, err)
+	assert.Contains(t, err.Error(), "invalid port")
+	assert.Contains(t, err.Error(), "123456")
+}
+
+func TestChallengeIPaddress(t *testing.T) {
+	_, apiURL := tester.SetupFakeAPI(t)
+
+	domain := "127.0.0.1"
+	port := "23457"
+	rd, _ := dns.ReverseAddr(domain)
+
+	mockValidate := func(_ *api.Core, _ string, chlng acme.Challenge) error {
+		conn, err := tls.Dial("tcp", net.JoinHostPort(domain, port), &tls.Config{
+			ServerName:         rd,
+			InsecureSkipVerify: true,
+		})
+		require.NoError(t, err, "Expected to connect to challenge server without an error")
+
+		// Expect the server to only return one certificate
+		connState := conn.ConnectionState()
+		assert.Len(t, connState.PeerCertificates, 1, "Expected the challenge server to return exactly one certificate")
+
+		remoteCert := connState.PeerCertificates[0]
+		assert.Len(t, remoteCert.DNSNames, 0, "Expected the challenge certificate to have no DNSNames entry in context of challenge for IP")
+		assert.Len(t, remoteCert.IPAddresses, 1, "Expected the challenge certificate to have exactly one IPAddresses entry")
+		assert.True(t, net.ParseIP("127.0.0.1").Equal(remoteCert.IPAddresses[0]), "challenge certificate IPAddress ")
+		assert.NotEmpty(t, remoteCert.Extensions, "Expected the challenge certificate to contain extensions")
+
+		var foundAcmeIdentifier bool
+		var extValue []byte
+		for _, ext := range remoteCert.Extensions {
+			if idPeAcmeIdentifierV1.Equal(ext.Id) {
+				assert.True(t, ext.Critical, "Expected the challenge certificate id-pe-acmeIdentifier extension to be marked as critical")
+				foundAcmeIdentifier = true
+				extValue = ext.Value
+				break
+			}
+		}
+
+		require.True(t, foundAcmeIdentifier, "Expected the challenge certificate to contain an extension with the id-pe-acmeIdentifier id,")
+		zBytes := sha256.Sum256([]byte(chlng.KeyAuthorization))
+		value, err := asn1.Marshal(zBytes[:sha256.Size])
+		require.NoError(t, err, "Expected marshaling of the keyAuth to return no error")
+
+		require.EqualValues(t, value, extValue, "Expected the challenge certificate id-pe-acmeIdentifier extension to contain the SHA-256 digest of the keyAuth")
+
+		return nil
+	}
+
+	privateKey, err := rsa.GenerateKey(rand.Reader, 512)
+	require.NoError(t, err, "Could not generate test key")
+
+	core, err := api.New(http.DefaultClient, "lego-test", apiURL+"/dir", "", privateKey)
+	require.NoError(t, err)
+
+	solver := NewChallenge(
+		core,
+		mockValidate,
+		&ProviderServer{port: "23457"},
+	)
+
+	authz := acme.Authorization{
+		Identifier: acme.Identifier{
+			Type:  "ip",
+			Value: domain,
+		},
+		Challenges: []acme.Challenge{
+			{Type: challenge.TLSALPN01.String(), Token: "tlsalpn1"},
+		},
+	}
+
+	require.NoError(t, solver.Solve(authz))
+}

cmd/account.go

@@ -0,0 +1,31 @@
+package cmd
+
+import (
+	"crypto"
+
+	"github.com/go-acme/lego/v4/registration"
+)
+
+// Account represents a users local saved credentials.
+type Account struct {
+	Email        string                 `json:"email"`
+	Registration *registration.Resource `json:"registration"`
+	key          crypto.PrivateKey
+}
+
+/** Implementation of the registration.User interface **/
+
+// GetEmail returns the email address for the account.
+func (a *Account) GetEmail() string {
+	return a.Email
+}
+
+// GetPrivateKey returns the private RSA account key.
+func (a *Account) GetPrivateKey() crypto.PrivateKey {
+	return a.key
+}
+
+// GetRegistration returns the server registration.
+func (a *Account) GetRegistration() *registration.Resource {
+	return a.Registration
+}

cmd/accounts_storage.go

@@ -0,0 +1,240 @@
+package cmd
+
+import (
+	"crypto"
+	"crypto/x509"
+	"encoding/json"
+	"encoding/pem"
+	"errors"
+	"net/url"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/go-acme/lego/v4/certcrypto"
+	"github.com/go-acme/lego/v4/lego"
+	"github.com/go-acme/lego/v4/log"
+	"github.com/go-acme/lego/v4/registration"
+	"github.com/urfave/cli/v2"
+)
+
+const (
+	baseAccountsRootFolderName = "accounts"
+	baseKeysFolderName         = "keys"
+	accountFileName            = "account.json"
+)
+
+// AccountsStorage A storage for account data.
+//
+// rootPath:
+//
+//	./.lego/accounts/
+//	     │      └── root accounts directory
+//	     └── "path" option
+//
+// rootUserPath:
+//
+//	./.lego/accounts/localhost_14000/hubert@hubert.com/
+//	     │      │             │             └── userID ("email" option)
+//	     │      │             └── CA server ("server" option)
+//	     │      └── root accounts directory
+//	     └── "path" option
+//
+// keysPath:
+//
+//	./.lego/accounts/localhost_14000/hubert@hubert.com/keys/
+//	     │      │             │             │           └── root keys directory
+//	     │      │             │             └── userID ("email" option)
+//	     │      │             └── CA server ("server" option)
+//	     │      └── root accounts directory
+//	     └── "path" option
+//
+// accountFilePath:
+//
+//	./.lego/accounts/localhost_14000/hubert@hubert.com/account.json
+//	     │      │             │             │             └── account file
+//	     │      │             │             └── userID ("email" option)
+//	     │      │             └── CA server ("server" option)
+//	     │      └── root accounts directory
+//	     └── "path" option
+type AccountsStorage struct {
+	userID          string
+	rootPath        string
+	rootUserPath    string
+	keysPath        string
+	accountFilePath string
+	ctx             *cli.Context
+}
+
+// NewAccountsStorage Creates a new AccountsStorage.
+func NewAccountsStorage(ctx *cli.Context) *AccountsStorage {
+	// TODO: move to account struct? Currently MUST pass email.
+	email := getEmail(ctx)
+
+	serverURL, err := url.Parse(ctx.String("server"))
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	rootPath := filepath.Join(ctx.String("path"), baseAccountsRootFolderName)
+	serverPath := strings.NewReplacer(":", "_", "/", string(os.PathSeparator)).Replace(serverURL.Host)
+	accountsPath := filepath.Join(rootPath, serverPath)
+	rootUserPath := filepath.Join(accountsPath, email)
+
+	return &AccountsStorage{
+		userID:          email,
+		rootPath:        rootPath,
+		rootUserPath:    rootUserPath,
+		keysPath:        filepath.Join(rootUserPath, baseKeysFolderName),
+		accountFilePath: filepath.Join(rootUserPath, accountFileName),
+		ctx:             ctx,
+	}
+}
+
+func (s *AccountsStorage) ExistsAccountFilePath() bool {
+	accountFile := filepath.Join(s.rootUserPath, accountFileName)
+	if _, err := os.Stat(accountFile); os.IsNotExist(err) {
+		return false
+	} else if err != nil {
+		log.Fatal(err)
+	}
+	return true
+}
+
+func (s *AccountsStorage) GetRootPath() string {
+	return s.rootPath
+}
+
+func (s *AccountsStorage) GetRootUserPath() string {
+	return s.rootUserPath
+}
+
+func (s *AccountsStorage) GetUserID() string {
+	return s.userID
+}
+
+func (s *AccountsStorage) Save(account *Account) error {
+	jsonBytes, err := json.MarshalIndent(account, "", "\t")
+	if err != nil {
+		return err
+	}
+
+	return os.WriteFile(s.accountFilePath, jsonBytes, filePerm)
+}
+
+func (s *AccountsStorage) LoadAccount(privateKey crypto.PrivateKey) *Account {
+	fileBytes, err := os.ReadFile(s.accountFilePath)
+	if err != nil {
+		log.Fatalf("Could not load file for account %s: %v", s.userID, err)
+	}
+
+	var account Account
+	err = json.Unmarshal(fileBytes, &account)
+	if err != nil {
+		log.Fatalf("Could not parse file for account %s: %v", s.userID, err)
+	}
+
+	account.key = privateKey
+
+	if account.Registration == nil || account.Registration.Body.Status == "" {
+		reg, err := tryRecoverRegistration(s.ctx, privateKey)
+		if err != nil {
+			log.Fatalf("Could not load account for %s. Registration is nil: %#v", s.userID, err)
+		}
+
+		account.Registration = reg
+		err = s.Save(&account)
+		if err != nil {
+			log.Fatalf("Could not save account for %s. Registration is nil: %#v", s.userID, err)
+		}
+	}
+
+	return &account
+}
+
+func (s *AccountsStorage) GetPrivateKey(keyType certcrypto.KeyType) crypto.PrivateKey {
+	accKeyPath := filepath.Join(s.keysPath, s.userID+".key")
+
+	if _, err := os.Stat(accKeyPath); os.IsNotExist(err) {
+		log.Printf("No key found for account %s. Generating a %s key.", s.userID, keyType)
+		s.createKeysFolder()
+
+		privateKey, err := generatePrivateKey(accKeyPath, keyType)
+		if err != nil {
+			log.Fatalf("Could not generate RSA private account key for account %s: %v", s.userID, err)
+		}
+
+		log.Printf("Saved key to %s", accKeyPath)
+		return privateKey
+	}
+
+	privateKey, err := loadPrivateKey(accKeyPath)
+	if err != nil {
+		log.Fatalf("Could not load RSA private key from file %s: %v", accKeyPath, err)
+	}
+
+	return privateKey
+}
+
+func (s *AccountsStorage) createKeysFolder() {
+	if err := createNonExistingFolder(s.keysPath); err != nil {
+		log.Fatalf("Could not check/create directory for account %s: %v", s.userID, err)
+	}
+}
+
+func generatePrivateKey(file string, keyType certcrypto.KeyType) (crypto.PrivateKey, error) {
+	privateKey, err := certcrypto.GeneratePrivateKey(keyType)
+	if err != nil {
+		return nil, err
+	}
+
+	certOut, err := os.Create(file)
+	if err != nil {
+		return nil, err
+	}
+	defer certOut.Close()
+
+	pemKey := certcrypto.PEMBlock(privateKey)
+	err = pem.Encode(certOut, pemKey)
+	if err != nil {
+		return nil, err
+	}
+
+	return privateKey, nil
+}
+
+func loadPrivateKey(file string) (crypto.PrivateKey, error) {
+	keyBytes, err := os.ReadFile(file)
+	if err != nil {
+		return nil, err
+	}
+
+	keyBlock, _ := pem.Decode(keyBytes)
+
+	switch keyBlock.Type {
+	case "RSA PRIVATE KEY":
+		return x509.ParsePKCS1PrivateKey(keyBlock.Bytes)
+	case "EC PRIVATE KEY":
+		return x509.ParseECPrivateKey(keyBlock.Bytes)
+	}
+
+	return nil, errors.New("unknown private key type")
+}
+
+func tryRecoverRegistration(ctx *cli.Context, privateKey crypto.PrivateKey) (*registration.Resource, error) {
+	// couldn't load account but got a key. Try to look the account up.
+	config := lego.NewConfig(&Account{key: privateKey})
+	config.CADirURL = ctx.String("server")
+	config.UserAgent = getUserAgent(ctx)
+
+	client, err := lego.NewClient(config)
+	if err != nil {
+		return nil, err
+	}
+
+	reg, err := client.Registration.ResolveAccountByKey()
+	if err != nil {
+		return nil, err
+	}
+	return reg, nil
+}

cmd/certs_storage.go

@@ -0,0 +1,295 @@
+package cmd
+
+import (
+	"bytes"
+	"crypto"
+	"crypto/rand"
+	"crypto/x509"
+	"encoding/json"
+	"encoding/pem"
+	"fmt"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/go-acme/lego/v4/certcrypto"
+	"github.com/go-acme/lego/v4/certificate"
+	"github.com/go-acme/lego/v4/log"
+	"github.com/urfave/cli/v2"
+	"golang.org/x/net/idna"
+	"software.sslmate.com/src/go-pkcs12"
+)
+
+const (
+	baseCertificatesFolderName = "certificates"
+	baseArchivesFolderName     = "archives"
+)
+
+const (
+	issuerExt   = ".issuer.crt"
+	certExt     = ".crt"
+	keyExt      = ".key"
+	pemExt      = ".pem"
+	pfxExt      = ".pfx"
+	resourceExt = ".json"
+)
+
+// CertificatesStorage a certificates' storage.
+//
+// rootPath:
+//
+//	./.lego/certificates/
+//	     │      └── root certificates directory
+//	     └── "path" option
+//
+// archivePath:
+//
+//	./.lego/archives/
+//	     │      └── archived certificates directory
+//	     └── "path" option
+type CertificatesStorage struct {
+	rootPath    string
+	archivePath string
+	pem         bool
+	pfx         bool
+	pfxPassword string
+	filename    string // Deprecated
+}
+
+// NewCertificatesStorage create a new certificates storage.
+func NewCertificatesStorage(ctx *cli.Context) *CertificatesStorage {
+	return &CertificatesStorage{
+		rootPath:    filepath.Join(ctx.String("path"), baseCertificatesFolderName),
+		archivePath: filepath.Join(ctx.String("path"), baseArchivesFolderName),
+		pem:         ctx.Bool("pem"),
+		pfx:         ctx.Bool("pfx"),
+		pfxPassword: ctx.String("pfx.pass"),
+		filename:    ctx.String("filename"),
+	}
+}
+
+func (s *CertificatesStorage) CreateRootFolder() {
+	err := createNonExistingFolder(s.rootPath)
+	if err != nil {
+		log.Fatalf("Could not check/create path: %v", err)
+	}
+}
+
+func (s *CertificatesStorage) CreateArchiveFolder() {
+	err := createNonExistingFolder(s.archivePath)
+	if err != nil {
+		log.Fatalf("Could not check/create path: %v", err)
+	}
+}
+
+func (s *CertificatesStorage) GetRootPath() string {
+	return s.rootPath
+}
+
+func (s *CertificatesStorage) SaveResource(certRes *certificate.Resource) {
+	domain := certRes.Domain
+
+	// We store the certificate, private key and metadata in different files
+	// as web servers would not be able to work with a combined file.
+	err := s.WriteFile(domain, certExt, certRes.Certificate)
+	if err != nil {
+		log.Fatalf("Unable to save Certificate for domain %s\n\t%v", domain, err)
+	}
+
+	if certRes.IssuerCertificate != nil {
+		err = s.WriteFile(domain, issuerExt, certRes.IssuerCertificate)
+		if err != nil {
+			log.Fatalf("Unable to save IssuerCertificate for domain %s\n\t%v", domain, err)
+		}
+	}
+
+	// if we were given a CSR, we don't know the private key
+	if certRes.PrivateKey != nil {
+		err = s.WriteCertificateFiles(domain, certRes)
+		if err != nil {
+			log.Fatalf("Unable to save PrivateKey for domain %s\n\t%v", domain, err)
+		}
+	} else if s.pem || s.pfx {
+		// we don't have the private key; can't write the .pem or .pfx file
+		log.Fatalf("Unable to save PEM or PFX without private key for domain %s. Are you using a CSR?", domain)
+	}
+
+	jsonBytes, err := json.MarshalIndent(certRes, "", "\t")
+	if err != nil {
+		log.Fatalf("Unable to marshal CertResource for domain %s\n\t%v", domain, err)
+	}
+
+	err = s.WriteFile(domain, resourceExt, jsonBytes)
+	if err != nil {
+		log.Fatalf("Unable to save CertResource for domain %s\n\t%v", domain, err)
+	}
+}
+
+func (s *CertificatesStorage) ReadResource(domain string) certificate.Resource {
+	raw, err := s.ReadFile(domain, resourceExt)
+	if err != nil {
+		log.Fatalf("Error while loading the meta data for domain %s\n\t%v", domain, err)
+	}
+
+	var resource certificate.Resource
+	if err = json.Unmarshal(raw, &resource); err != nil {
+		log.Fatalf("Error while marshaling the meta data for domain %s\n\t%v", domain, err)
+	}
+
+	return resource
+}
+
+func (s *CertificatesStorage) ExistsFile(domain, extension string) bool {
+	filePath := s.GetFileName(domain, extension)
+
+	if _, err := os.Stat(filePath); os.IsNotExist(err) {
+		return false
+	} else if err != nil {
+		log.Fatal(err)
+	}
+	return true
+}
+
+func (s *CertificatesStorage) ReadFile(domain, extension string) ([]byte, error) {
+	return os.ReadFile(s.GetFileName(domain, extension))
+}
+
+func (s *CertificatesStorage) GetFileName(domain, extension string) string {
+	filename := sanitizedDomain(domain) + extension
+	return filepath.Join(s.rootPath, filename)
+}
+
+func (s *CertificatesStorage) ReadCertificate(domain, extension string) ([]*x509.Certificate, error) {
+	content, err := s.ReadFile(domain, extension)
+	if err != nil {
+		return nil, err
+	}
+
+	// The input may be a bundle or a single certificate.
+	return certcrypto.ParsePEMBundle(content)
+}
+
+func (s *CertificatesStorage) WriteFile(domain, extension string, data []byte) error {
+	var baseFileName string
+	if s.filename != "" {
+		baseFileName = s.filename
+	} else {
+		baseFileName = sanitizedDomain(domain)
+	}
+
+	filePath := filepath.Join(s.rootPath, baseFileName+extension)
+
+	return os.WriteFile(filePath, data, filePerm)
+}
+
+func (s *CertificatesStorage) WriteCertificateFiles(domain string, certRes *certificate.Resource) error {
+	err := s.WriteFile(domain, keyExt, certRes.PrivateKey)
+	if err != nil {
+		return fmt.Errorf("unable to save key file: %w", err)
+	}
+
+	if s.pem {
+		err = s.WriteFile(domain, pemExt, bytes.Join([][]byte{certRes.Certificate, certRes.PrivateKey}, nil))
+		if err != nil {
+			return fmt.Errorf("unable to save PEM file: %w", err)
+		}
+	}
+
+	if s.pfx {
+		err = s.WritePFXFile(domain, certRes)
+		if err != nil {
+			return fmt.Errorf("unable to save PFX file: %w", err)
+		}
+	}
+
+	return nil
+}
+
+func (s *CertificatesStorage) WritePFXFile(domain string, certRes *certificate.Resource) error {
+	certPemBlock, _ := pem.Decode(certRes.Certificate)
+	if certPemBlock == nil {
+		return fmt.Errorf("unable to parse Certificate for domain %s", domain)
+	}
+
+	cert, err := x509.ParseCertificate(certPemBlock.Bytes)
+	if err != nil {
+		return fmt.Errorf("unable to load Certificate for domain %s: %w", domain, err)
+	}
+
+	issuerCertPemBlock, _ := pem.Decode(certRes.IssuerCertificate)
+	if issuerCertPemBlock == nil {
+		return fmt.Errorf("unable to parse Issuer Certificate for domain %s", domain)
+	}
+
+	issuerCert, err := x509.ParseCertificate(issuerCertPemBlock.Bytes)
+	if err != nil {
+		return fmt.Errorf("unable to load Issuer Certificate for domain %s: %w", domain, err)
+	}
+
+	keyPemBlock, _ := pem.Decode(certRes.PrivateKey)
+	if keyPemBlock == nil {
+		return fmt.Errorf("unable to parse PrivateKey for domain %s", domain)
+	}
+
+	var privateKey crypto.Signer
+	var keyErr error
+
+	switch keyPemBlock.Type {
+	case "RSA PRIVATE KEY":
+		privateKey, keyErr = x509.ParsePKCS1PrivateKey(keyPemBlock.Bytes)
+		if keyErr != nil {
+			return fmt.Errorf("unable to load RSA PrivateKey for domain %s: %w", domain, keyErr)
+		}
+	case "EC PRIVATE KEY":
+		privateKey, keyErr = x509.ParseECPrivateKey(keyPemBlock.Bytes)
+		if keyErr != nil {
+			return fmt.Errorf("unable to load EC PrivateKey for domain %s: %w", domain, keyErr)
+		}
+	default:
+		return fmt.Errorf("unsupported PrivateKey type '%s' for domain %s", keyPemBlock.Type, domain)
+	}
+
+	pfxBytes, err := pkcs12.Encode(rand.Reader, privateKey, cert, []*x509.Certificate{issuerCert}, s.pfxPassword)
+	if err != nil {
+		return fmt.Errorf("unable to encode PFX data for domain %s: %w", domain, err)
+	}
+
+	return s.WriteFile(domain, pfxExt, pfxBytes)
+}
+
+func (s *CertificatesStorage) MoveToArchive(domain string) error {
+	baseFilename := filepath.Join(s.rootPath, sanitizedDomain(domain))
+
+	matches, err := filepath.Glob(baseFilename + ".*")
+	if err != nil {
+		return err
+	}
+
+	for _, oldFile := range matches {
+		if strings.TrimSuffix(oldFile, filepath.Ext(oldFile)) != baseFilename && oldFile != baseFilename+issuerExt {
+			continue
+		}
+
+		date := strconv.FormatInt(time.Now().Unix(), 10)
+		filename := date + "." + filepath.Base(oldFile)
+		newFile := filepath.Join(s.archivePath, filename)
+
+		err = os.Rename(oldFile, newFile)
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+// sanitizedDomain Make sure no funny chars are in the cert names (like wildcards ;)).
+func sanitizedDomain(domain string) string {
+	safe, err := idna.ToASCII(strings.NewReplacer(":", "-", "*", "_").Replace(domain))
+	if err != nil {
+		log.Fatal(err)
+	}
+	return safe
+}

cmd/certs_storage_test.go

@@ -0,0 +1,115 @@
+package cmd
+
+import (
+	"os"
+	"path/filepath"
+	"regexp"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestCertificatesStorage_MoveToArchive(t *testing.T) {
+	domain := "example.com"
+
+	storage := CertificatesStorage{
+		rootPath:    t.TempDir(),
+		archivePath: t.TempDir(),
+	}
+
+	domainFiles := generateTestFiles(t, storage.rootPath, domain)
+
+	err := storage.MoveToArchive(domain)
+	require.NoError(t, err)
+
+	for _, file := range domainFiles {
+		assert.NoFileExists(t, file)
+	}
+
+	root, err := os.ReadDir(storage.rootPath)
+	require.NoError(t, err)
+	require.Empty(t, root)
+
+	archive, err := os.ReadDir(storage.archivePath)
+	require.NoError(t, err)
+
+	require.Len(t, archive, len(domainFiles))
+	assert.Regexp(t, `\d+\.`+regexp.QuoteMeta(domain), archive[0].Name())
+}
+
+func TestCertificatesStorage_MoveToArchive_noFileRelatedToDomain(t *testing.T) {
+	domain := "example.com"
+
+	storage := CertificatesStorage{
+		rootPath:    t.TempDir(),
+		archivePath: t.TempDir(),
+	}
+
+	domainFiles := generateTestFiles(t, storage.rootPath, "example.org")
+
+	err := storage.MoveToArchive(domain)
+	require.NoError(t, err)
+
+	for _, file := range domainFiles {
+		assert.FileExists(t, file)
+	}
+
+	root, err := os.ReadDir(storage.rootPath)
+	require.NoError(t, err)
+	assert.Len(t, root, len(domainFiles))
+
+	archive, err := os.ReadDir(storage.archivePath)
+	require.NoError(t, err)
+
+	assert.Empty(t, archive)
+}
+
+func TestCertificatesStorage_MoveToArchive_ambiguousDomain(t *testing.T) {
+	domain := "example.com"
+
+	storage := CertificatesStorage{
+		rootPath:    t.TempDir(),
+		archivePath: t.TempDir(),
+	}
+
+	domainFiles := generateTestFiles(t, storage.rootPath, domain)
+	otherDomainFiles := generateTestFiles(t, storage.rootPath, domain+".example.org")
+
+	err := storage.MoveToArchive(domain)
+	require.NoError(t, err)
+
+	for _, file := range domainFiles {
+		assert.NoFileExists(t, file)
+	}
+
+	for _, file := range otherDomainFiles {
+		assert.FileExists(t, file)
+	}
+
+	root, err := os.ReadDir(storage.rootPath)
+	require.NoError(t, err)
+	require.Len(t, root, len(otherDomainFiles))
+
+	archive, err := os.ReadDir(storage.archivePath)
+	require.NoError(t, err)
+
+	require.Len(t, archive, len(domainFiles))
+	assert.Regexp(t, `\d+\.`+regexp.QuoteMeta(domain), archive[0].Name())
+}
+
+func generateTestFiles(t *testing.T, dir, domain string) []string {
+	t.Helper()
+
+	var filenames []string
+
+	for _, ext := range []string{issuerExt, certExt, keyExt, pemExt, pfxExt, resourceExt} {
+		filename := filepath.Join(dir, domain+ext)
+		err := os.WriteFile(filename, []byte("test"), 0o666)
+		require.NoError(t, err)
+
+		filenames = append(filenames, filename)
+	}
+
+	return filenames
+}

cmd/cmd.go

@@ -0,0 +1,14 @@
+package cmd
+
+import "github.com/urfave/cli/v2"
+
+// CreateCommands Creates all CLI commands.
+func CreateCommands() []*cli.Command {
+	return []*cli.Command{
+		createRun(),
+		createRevoke(),
+		createRenew(),
+		createDNSHelp(),
+		createList(),
+	}
+}

cmd/cmd_before.go

@@ -0,0 +1,23 @@
+package cmd
+
+import (
+	"github.com/go-acme/lego/v4/log"
+	"github.com/urfave/cli/v2"
+)
+
+func Before(ctx *cli.Context) error {
+	if ctx.String("path") == "" {
+		log.Fatal("Could not determine current working directory. Please pass --path.")
+	}
+
+	err := createNonExistingFolder(ctx.String("path"))
+	if err != nil {
+		log.Fatalf("Could not check/create path: %v", err)
+	}
+
+	if ctx.String("server") == "" {
+		log.Fatal("Could not determine current working server. Please pass --server.")
+	}
+
+	return nil
+}

cmd/cmd_dnshelp.go

@@ -0,0 +1,73 @@
+package cmd
+
+import (
+	"fmt"
+	"io"
+	"strings"
+	"text/tabwriter"
+
+	"github.com/urfave/cli/v2"
+)
+
+func createDNSHelp() *cli.Command {
+	return &cli.Command{
+		Name:   "dnshelp",
+		Usage:  "Shows additional help for the '--dns' global option",
+		Action: dnsHelp,
+		Flags: []cli.Flag{
+			&cli.StringFlag{
+				Name:    "code",
+				Aliases: []string{"c"},
+				Usage:   fmt.Sprintf("DNS code: %s", allDNSCodes()),
+			},
+		},
+	}
+}
+
+func dnsHelp(ctx *cli.Context) error {
+	code := ctx.String("code")
+	if code == "" {
+		w := tabwriter.NewWriter(ctx.App.Writer, 0, 0, 2, ' ', 0)
+		ew := &errWriter{w: w}
+
+		ew.writeln(`Credentials for DNS providers must be passed through environment variables.`)
+		ew.writeln()
+		ew.writeln(`To display the documentation for a specific DNS provider, run:`)
+		ew.writeln()
+		ew.writeln("\t$ lego dnshelp -c code")
+		ew.writeln()
+		ew.writeln("Supported DNS providers:")
+		ew.writef("\t%s\n", allDNSCodes())
+		ew.writeln()
+		ew.writeln("More information: https://go-acme.github.io/lego/dns")
+
+		if ew.err != nil {
+			return ew.err
+		}
+
+		return w.Flush()
+	}
+
+	return displayDNSHelp(ctx.App.Writer, strings.ToLower(code))
+}
+
+type errWriter struct {
+	w   io.Writer
+	err error
+}
+
+func (ew *errWriter) writeln(a ...interface{}) {
+	if ew.err != nil {
+		return
+	}
+
+	_, ew.err = fmt.Fprintln(ew.w, a...)
+}
+
+func (ew *errWriter) writef(format string, a ...interface{}) {
+	if ew.err != nil {
+		return
+	}
+
+	_, ew.err = fmt.Fprintf(ew.w, format, a...)
+}

cmd/cmd_list.go

@@ -0,0 +1,139 @@
+package cmd
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/url"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/go-acme/lego/v4/certcrypto"
+	"github.com/urfave/cli/v2"
+)
+
+func createList() *cli.Command {
+	return &cli.Command{
+		Name:   "list",
+		Usage:  "Display certificates and accounts information.",
+		Action: list,
+		Flags: []cli.Flag{
+			&cli.BoolFlag{
+				Name:    "accounts",
+				Aliases: []string{"a"},
+				Usage:   "Display accounts.",
+			},
+			&cli.BoolFlag{
+				Name:    "names",
+				Aliases: []string{"n"},
+				Usage:   "Display certificate common names only.",
+			},
+			// fake email, needed by NewAccountsStorage
+			&cli.StringFlag{
+				Name:   "email",
+				Value:  "unknown",
+				Hidden: true,
+			},
+		},
+	}
+}
+
+func list(ctx *cli.Context) error {
+	if ctx.Bool("accounts") && !ctx.Bool("names") {
+		if err := listAccount(ctx); err != nil {
+			return err
+		}
+	}
+
+	return listCertificates(ctx)
+}
+
+func listCertificates(ctx *cli.Context) error {
+	certsStorage := NewCertificatesStorage(ctx)
+
+	matches, err := filepath.Glob(filepath.Join(certsStorage.GetRootPath(), "*.crt"))
+	if err != nil {
+		return err
+	}
+
+	names := ctx.Bool("names")
+
+	if len(matches) == 0 {
+		if !names {
+			fmt.Println("No certificates found.")
+		}
+		return nil
+	}
+
+	if !names {
+		fmt.Println("Found the following certs:")
+	}
+
+	for _, filename := range matches {
+		if strings.HasSuffix(filename, ".issuer.crt") {
+			continue
+		}
+
+		data, err := os.ReadFile(filename)
+		if err != nil {
+			return err
+		}
+
+		pCert, err := certcrypto.ParsePEMCertificate(data)
+		if err != nil {
+			return err
+		}
+
+		if names {
+			fmt.Println(pCert.Subject.CommonName)
+		} else {
+			fmt.Println("  Certificate Name:", pCert.Subject.CommonName)
+			fmt.Println("    Domains:", strings.Join(pCert.DNSNames, ", "))
+			fmt.Println("    Expiry Date:", pCert.NotAfter)
+			fmt.Println("    Certificate Path:", filename)
+			fmt.Println()
+		}
+	}
+
+	return nil
+}
+
+func listAccount(ctx *cli.Context) error {
+	accountsStorage := NewAccountsStorage(ctx)
+
+	matches, err := filepath.Glob(filepath.Join(accountsStorage.GetRootPath(), "*", "*", "*.json"))
+	if err != nil {
+		return err
+	}
+
+	if len(matches) == 0 {
+		fmt.Println("No accounts found.")
+		return nil
+	}
+
+	fmt.Println("Found the following accounts:")
+	for _, filename := range matches {
+		data, err := os.ReadFile(filename)
+		if err != nil {
+			return err
+		}
+
+		var account Account
+		err = json.Unmarshal(data, &account)
+		if err != nil {
+			return err
+		}
+
+		uri, err := url.Parse(account.Registration.URI)
+		if err != nil {
+			return err
+		}
+
+		fmt.Println("  Email:", account.Email)
+		fmt.Println("  Server:", uri.Host)
+		fmt.Println("  Path:", filepath.Dir(filename))
+		fmt.Println()
+	}
+
+	return nil
+}

cmd/cmd_renew.go

@@ -0,0 +1,383 @@
+package cmd
+
+import (
+	"crypto"
+	"crypto/x509"
+	"errors"
+	"math/rand"
+	"os"
+	"time"
+
+	"github.com/go-acme/lego/v4/acme/api"
+	"github.com/go-acme/lego/v4/certcrypto"
+	"github.com/go-acme/lego/v4/certificate"
+	"github.com/go-acme/lego/v4/lego"
+	"github.com/go-acme/lego/v4/log"
+	"github.com/mattn/go-isatty"
+	"github.com/urfave/cli/v2"
+)
+
+const (
+	renewEnvAccountEmail = "LEGO_ACCOUNT_EMAIL"
+	renewEnvCertDomain   = "LEGO_CERT_DOMAIN"
+	renewEnvCertPath     = "LEGO_CERT_PATH"
+	renewEnvCertKeyPath  = "LEGO_CERT_KEY_PATH"
+	renewEnvCertPEMPath  = "LEGO_CERT_PEM_PATH"
+	renewEnvCertPFXPath  = "LEGO_CERT_PFX_PATH"
+)
+
+func createRenew() *cli.Command {
+	return &cli.Command{
+		Name:   "renew",
+		Usage:  "Renew a certificate",
+		Action: renew,
+		Before: func(ctx *cli.Context) error {
+			// we require either domains or csr, but not both
+			hasDomains := len(ctx.StringSlice("domains")) > 0
+			hasCsr := len(ctx.String("csr")) > 0
+			if hasDomains && hasCsr {
+				log.Fatal("Please specify either --domains/-d or --csr/-c, but not both")
+			}
+			if !hasDomains && !hasCsr {
+				log.Fatal("Please specify --domains/-d (or --csr/-c if you already have a CSR)")
+			}
+			return nil
+		},
+		Flags: []cli.Flag{
+			&cli.IntFlag{
+				Name:  "days",
+				Value: 30,
+				Usage: "The number of days left on a certificate to renew it.",
+			},
+			&cli.BoolFlag{
+				Name:  "ari-enable",
+				Usage: "Use the renewalInfo endpoint (draft-ietf-acme-ari) to check if a certificate should be renewed.",
+			},
+			&cli.StringFlag{
+				Name:  "ari-hash-name",
+				Value: crypto.SHA256.String(),
+				Usage: "The string representation of the hash expected by the renewalInfo endpoint (e.g. \"SHA-256\").",
+			},
+			&cli.DurationFlag{
+				Name:  "ari-wait-to-renew-duration",
+				Usage: "The maximum duration you're willing to sleep for a renewal time returned by the renewalInfo endpoint.",
+			},
+			&cli.BoolFlag{
+				Name:  "reuse-key",
+				Usage: "Used to indicate you want to reuse your current private key for the new certificate.",
+			},
+			&cli.BoolFlag{
+				Name:  "no-bundle",
+				Usage: "Do not create a certificate bundle by adding the issuers certificate to the new certificate.",
+			},
+			&cli.BoolFlag{
+				Name: "must-staple",
+				Usage: "Include the OCSP must staple TLS extension in the CSR and generated certificate." +
+					" Only works if the CSR is generated by lego.",
+			},
+			&cli.TimestampFlag{
+				Name:   "not-before",
+				Usage:  "Set the notBefore field in the certificate (RFC3339 format)",
+				Layout: time.RFC3339,
+			},
+			&cli.TimestampFlag{
+				Name:   "not-after",
+				Usage:  "Set the notAfter field in the certificate (RFC3339 format)",
+				Layout: time.RFC3339,
+			},
+			&cli.StringFlag{
+				Name: "preferred-chain",
+				Usage: "If the CA offers multiple certificate chains, prefer the chain with an issuer matching this Subject Common Name." +
+					" If no match, the default offered chain will be used.",
+			},
+			&cli.StringFlag{
+				Name:  "always-deactivate-authorizations",
+				Usage: "Force the authorizations to be relinquished even if the certificate request was successful.",
+			},
+			&cli.StringFlag{
+				Name:  "renew-hook",
+				Usage: "Define a hook. The hook is executed only when the certificates are effectively renewed.",
+			},
+			&cli.BoolFlag{
+				Name: "no-random-sleep",
+				Usage: "Do not add a random sleep before the renewal." +
+					" We do not recommend using this flag if you are doing your renewals in an automated way.",
+			},
+		},
+	}
+}
+
+func renew(ctx *cli.Context) error {
+	account, client := setup(ctx, NewAccountsStorage(ctx))
+	setupChallenges(ctx, client)
+
+	if account.Registration == nil {
+		log.Fatalf("Account %s is not registered. Use 'run' to register a new account.\n", account.Email)
+	}
+
+	certsStorage := NewCertificatesStorage(ctx)
+
+	bundle := !ctx.Bool("no-bundle")
+
+	meta := map[string]string{renewEnvAccountEmail: account.Email}
+
+	// CSR
+	if ctx.IsSet("csr") {
+		return renewForCSR(ctx, client, certsStorage, bundle, meta)
+	}
+
+	// Domains
+	return renewForDomains(ctx, client, certsStorage, bundle, meta)
+}
+
+func renewForDomains(ctx *cli.Context, client *lego.Client, certsStorage *CertificatesStorage, bundle bool, meta map[string]string) error {
+	domains := ctx.StringSlice("domains")
+	domain := domains[0]
+
+	// load the cert resource from files.
+	// We store the certificate, private key and metadata in different files
+	// as web servers would not be able to work with a combined file.
+	certificates, err := certsStorage.ReadCertificate(domain, ".crt")
+	if err != nil {
+		log.Fatalf("Error while loading the certificate for domain %s\n\t%v", domain, err)
+	}
+
+	cert := certificates[0]
+
+	var ariRenewalTime *time.Time
+	if ctx.Bool("ari-enable") {
+		if len(certificates) < 2 {
+			log.Warnf("[%s] Certificate bundle does not contain issuer, cannot use the renewalInfo endpoint", domain)
+		} else {
+			ariRenewalTime = getARIRenewalTime(ctx, certificates[0], certificates[1], domain, client)
+		}
+		if ariRenewalTime != nil {
+			now := time.Now().UTC()
+			// Figure out if we need to sleep before renewing.
+			if ariRenewalTime.After(now) {
+				log.Infof("[%s] Sleeping %s until renewal time %s", domain, ariRenewalTime.Sub(now), ariRenewalTime)
+				time.Sleep(ariRenewalTime.Sub(now))
+			}
+		}
+	}
+
+	if ariRenewalTime == nil && !needRenewal(cert, domain, ctx.Int("days")) {
+		return nil
+	}
+
+	// This is just meant to be informal for the user.
+	timeLeft := cert.NotAfter.Sub(time.Now().UTC())
+	log.Infof("[%s] acme: Trying renewal with %d hours remaining", domain, int(timeLeft.Hours()))
+
+	certDomains := certcrypto.ExtractDomains(cert)
+
+	var privateKey crypto.PrivateKey
+	if ctx.Bool("reuse-key") {
+		keyBytes, errR := certsStorage.ReadFile(domain, ".key")
+		if errR != nil {
+			log.Fatalf("Error while loading the private key for domain %s\n\t%v", domain, errR)
+		}
+
+		privateKey, errR = certcrypto.ParsePEMPrivateKey(keyBytes)
+		if errR != nil {
+			return errR
+		}
+	}
+
+	// https://github.com/go-acme/lego/issues/1656
+	// https://github.com/certbot/certbot/blob/284023a1b7672be2bd4018dd7623b3b92197d4b0/certbot/certbot/_internal/renewal.py#L435-L440
+	if !isatty.IsTerminal(os.Stdout.Fd()) && !ctx.Bool("no-random-sleep") {
+		// https://github.com/certbot/certbot/blob/284023a1b7672be2bd4018dd7623b3b92197d4b0/certbot/certbot/_internal/renewal.py#L472
+		const jitter = 8 * time.Minute
+		rnd := rand.New(rand.NewSource(time.Now().UnixNano()))
+		sleepTime := time.Duration(rnd.Int63n(int64(jitter)))
+
+		log.Infof("renewal: random delay of %s", sleepTime)
+		time.Sleep(sleepTime)
+	}
+
+	request := certificate.ObtainRequest{
+		Domains:                        merge(certDomains, domains),
+		PrivateKey:                     privateKey,
+		MustStaple:                     ctx.Bool("must-staple"),
+		NotBefore:                      getTime(ctx, "not-before"),
+		NotAfter:                       getTime(ctx, "not-after"),
+		Bundle:                         bundle,
+		PreferredChain:                 ctx.String("preferred-chain"),
+		AlwaysDeactivateAuthorizations: ctx.Bool("always-deactivate-authorizations"),
+	}
+
+	certRes, err := client.Certificate.Obtain(request)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	certsStorage.SaveResource(certRes)
+
+	if ariRenewalTime != nil {
+		// Post to the renewalInfo endpoint to indicate that we have renewed and replaced the certificate.
+		err := client.Certificate.UpdateRenewalInfo(certificate.RenewalInfoRequest{
+			Cert:     certificates[0],
+			Issuer:   certificates[1],
+			HashName: ctx.String("ari-hash-name"),
+		})
+		if err != nil {
+			log.Warnf("[%s] Failed to update renewal info: %v", domain, err)
+		}
+	}
+
+	meta[renewEnvCertDomain] = domain
+	meta[renewEnvCertPath] = certsStorage.GetFileName(domain, ".crt")
+	meta[renewEnvCertKeyPath] = certsStorage.GetFileName(domain, ".key")
+	meta[renewEnvCertPEMPath] = certsStorage.GetFileName(domain, ".pem")
+	meta[renewEnvCertPFXPath] = certsStorage.GetFileName(domain, ".pfx")
+
+	return launchHook(ctx.String("renew-hook"), meta)
+}
+
+func renewForCSR(ctx *cli.Context, client *lego.Client, certsStorage *CertificatesStorage, bundle bool, meta map[string]string) error {
+	csr, err := readCSRFile(ctx.String("csr"))
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	domain := csr.Subject.CommonName
+
+	// load the cert resource from files.
+	// We store the certificate, private key and metadata in different files
+	// as web servers would not be able to work with a combined file.
+	certificates, err := certsStorage.ReadCertificate(domain, ".crt")
+	if err != nil {
+		log.Fatalf("Error while loading the certificate for domain %s\n\t%v", domain, err)
+	}
+
+	cert := certificates[0]
+
+	var ariRenewalTime *time.Time
+	if ctx.Bool("ari-enable") {
+		if len(certificates) < 2 {
+			log.Warnf("[%s] Certificate bundle does not contain issuer, cannot use the renewalInfo endpoint", domain)
+		} else {
+			ariRenewalTime = getARIRenewalTime(ctx, certificates[0], certificates[1], domain, client)
+		}
+		if ariRenewalTime != nil {
+			now := time.Now().UTC()
+			// Figure out if we need to sleep before renewing.
+			if ariRenewalTime.After(now) {
+				log.Infof("[%s] Sleeping %s until renewal time %s", domain, ariRenewalTime.Sub(now), ariRenewalTime)
+				time.Sleep(ariRenewalTime.Sub(now))
+			}
+		}
+	}
+
+	if ariRenewalTime == nil && !needRenewal(cert, domain, ctx.Int("days")) {
+		return nil
+	}
+
+	// This is just meant to be informal for the user.
+	timeLeft := cert.NotAfter.Sub(time.Now().UTC())
+	log.Infof("[%s] acme: Trying renewal with %d hours remaining", domain, int(timeLeft.Hours()))
+
+	request := certificate.ObtainForCSRRequest{
+		CSR:                            csr,
+		NotBefore:                      getTime(ctx, "not-before"),
+		NotAfter:                       getTime(ctx, "not-after"),
+		Bundle:                         bundle,
+		PreferredChain:                 ctx.String("preferred-chain"),
+		AlwaysDeactivateAuthorizations: ctx.Bool("always-deactivate-authorizations"),
+	}
+
+	certRes, err := client.Certificate.ObtainForCSR(request)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	certsStorage.SaveResource(certRes)
+
+	if ariRenewalTime != nil {
+		// Post to the renewalInfo endpoint to indicate that we have renewed and replaced the certificate.
+		err := client.Certificate.UpdateRenewalInfo(certificate.RenewalInfoRequest{
+			Cert:     certificates[0],
+			Issuer:   certificates[1],
+			HashName: ctx.String("ari-hash-name"),
+		})
+		if err != nil {
+			log.Warnf("[%s] Failed to update renewal info: %v", domain, err)
+		}
+	}
+
+	meta[renewEnvCertDomain] = domain
+	meta[renewEnvCertPath] = certsStorage.GetFileName(domain, ".crt")
+	meta[renewEnvCertKeyPath] = certsStorage.GetFileName(domain, ".key")
+
+	return launchHook(ctx.String("renew-hook"), meta)
+}
+
+func needRenewal(x509Cert *x509.Certificate, domain string, days int) bool {
+	if x509Cert.IsCA {
+		log.Fatalf("[%s] Certificate bundle starts with a CA certificate", domain)
+	}
+
+	if days >= 0 {
+		notAfter := int(time.Until(x509Cert.NotAfter).Hours() / 24.0)
+		if notAfter > days {
+			log.Printf("[%s] The certificate expires in %d days, the number of days defined to perform the renewal is %d: no renewal.",
+				domain, notAfter, days)
+			return false
+		}
+	}
+
+	return true
+}
+
+// getARIRenewalTime checks if the certificate needs to be renewed using the renewalInfo endpoint.
+func getARIRenewalTime(ctx *cli.Context, cert, issuer *x509.Certificate, domain string, client *lego.Client) *time.Time {
+	if cert.IsCA {
+		log.Fatalf("[%s] Certificate bundle starts with a CA certificate", domain)
+	}
+
+	renewalInfo, err := client.Certificate.GetRenewalInfo(certificate.RenewalInfoRequest{
+		Cert:     cert,
+		Issuer:   issuer,
+		HashName: ctx.String("ari-hash-name"),
+	})
+	if err != nil {
+		if errors.Is(err, api.ErrNoARI) {
+			// The server does not advertise a renewal info endpoint.
+			log.Warnf("[%s] acme: %w", domain, err)
+			return nil
+		}
+		log.Warnf("[%s] acme: calling renewal info endpoint: %w", domain, err)
+		return nil
+	}
+
+	now := time.Now().UTC()
+	renewalTime := renewalInfo.ShouldRenewAt(now, ctx.Duration("ari-wait-to-renew-duration"))
+	if renewalTime == nil {
+		log.Infof("[%s] acme: renewalInfo endpoint indicates that renewal is not needed", domain)
+		return nil
+	}
+	log.Infof("[%s] acme: renewalInfo endpoint indicates that renewal is needed", domain)
+
+	if renewalInfo.ExplanationURL != "" {
+		log.Infof("[%s] acme: renewalInfo endpoint provided an explanation: %s", domain, renewalInfo.ExplanationURL)
+	}
+
+	return renewalTime
+}
+
+func merge(prevDomains, nextDomains []string) []string {
+	for _, next := range nextDomains {
+		var found bool
+		for _, prev := range prevDomains {
+			if prev == next {
+				found = true
+				break
+			}
+		}
+		if !found {
+			prevDomains = append(prevDomains, next)
+		}
+	}
+	return prevDomains
+}

cmd/cmd_renew_test.go

@@ -0,0 +1,118 @@
+package cmd
+
+import (
+	"crypto/x509"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func Test_merge(t *testing.T) {
+	testCases := []struct {
+		desc        string
+		prevDomains []string
+		nextDomains []string
+		expected    []string
+	}{
+		{
+			desc:        "all empty",
+			prevDomains: []string{},
+			nextDomains: []string{},
+			expected:    []string{},
+		},
+		{
+			desc:        "next empty",
+			prevDomains: []string{"a", "b", "c"},
+			nextDomains: []string{},
+			expected:    []string{"a", "b", "c"},
+		},
+		{
+			desc:        "prev empty",
+			prevDomains: []string{},
+			nextDomains: []string{"a", "b", "c"},
+			expected:    []string{"a", "b", "c"},
+		},
+		{
+			desc:        "merge append",
+			prevDomains: []string{"a", "b", "c"},
+			nextDomains: []string{"a", "c", "d"},
+			expected:    []string{"a", "b", "c", "d"},
+		},
+		{
+			desc:        "merge same",
+			prevDomains: []string{"a", "b", "c"},
+			nextDomains: []string{"a", "b", "c"},
+			expected:    []string{"a", "b", "c"},
+		},
+	}
+
+	for _, test := range testCases {
+		test := test
+		t.Run(test.desc, func(t *testing.T) {
+			t.Parallel()
+
+			actual := merge(test.prevDomains, test.nextDomains)
+			assert.Equal(t, test.expected, actual)
+		})
+	}
+}
+
+func Test_needRenewal(t *testing.T) {
+	testCases := []struct {
+		desc     string
+		x509Cert *x509.Certificate
+		days     int
+		expected bool
+	}{
+		{
+			desc: "30 days, NotAfter now",
+			x509Cert: &x509.Certificate{
+				NotAfter: time.Now(),
+			},
+			days:     30,
+			expected: true,
+		},
+		{
+			desc: "30 days, NotAfter 31 days",
+			x509Cert: &x509.Certificate{
+				NotAfter: time.Now().Add(31*24*time.Hour + 1*time.Second),
+			},
+			days:     30,
+			expected: false,
+		},
+		{
+			desc: "30 days, NotAfter 30 days",
+			x509Cert: &x509.Certificate{
+				NotAfter: time.Now().Add(30 * 24 * time.Hour),
+			},
+			days:     30,
+			expected: true,
+		},
+		{
+			desc: "0 days, NotAfter 30 days: only the day of the expiration",
+			x509Cert: &x509.Certificate{
+				NotAfter: time.Now().Add(30 * 24 * time.Hour),
+			},
+			days:     0,
+			expected: false,
+		},
+		{
+			desc: "-1 days, NotAfter 30 days: always renew",
+			x509Cert: &x509.Certificate{
+				NotAfter: time.Now().Add(30 * 24 * time.Hour),
+			},
+			days:     -1,
+			expected: true,
+		},
+	}
+
+	for _, test := range testCases {
+		test := test
+		t.Run(test.desc, func(t *testing.T) {
+			actual := needRenewal(test.x509Cert, "foo.com", test.days)
+
+			assert.Equal(t, test.expected, actual)
+		})
+	}
+}

cmd/cmd_revoke.go

@@ -0,0 +1,76 @@
+package cmd
+
+import (
+	"github.com/go-acme/lego/v4/acme"
+	"github.com/go-acme/lego/v4/log"
+	"github.com/urfave/cli/v2"
+)
+
+func createRevoke() *cli.Command {
+	return &cli.Command{
+		Name:   "revoke",
+		Usage:  "Revoke a certificate",
+		Action: revoke,
+		Flags: []cli.Flag{
+			&cli.BoolFlag{
+				Name:    "keep",
+				Aliases: []string{"k"},
+				Usage:   "Keep the certificates after the revocation instead of archiving them.",
+			},
+			&cli.UintFlag{
+				Name: "reason",
+				Usage: "Identifies the reason for the certificate revocation." +
+					" See https://www.rfc-editor.org/rfc/rfc5280.html#section-5.3.1." +
+					" Valid values are:" +
+					" 0 (unspecified), 1 (keyCompromise), 2 (cACompromise), 3 (affiliationChanged)," +
+					" 4 (superseded), 5 (cessationOfOperation), 6 (certificateHold), 8 (removeFromCRL)," +
+					" 9 (privilegeWithdrawn), or 10 (aACompromise).",
+				Value: acme.CRLReasonUnspecified,
+			},
+		},
+	}
+}
+
+func revoke(ctx *cli.Context) error {
+	acc, client := setup(ctx, NewAccountsStorage(ctx))
+
+	if acc.Registration == nil {
+		log.Fatalf("Account %s is not registered. Use 'run' to register a new account.\n", acc.Email)
+	}
+
+	certsStorage := NewCertificatesStorage(ctx)
+	certsStorage.CreateRootFolder()
+
+	for _, domain := range ctx.StringSlice("domains") {
+		log.Printf("Trying to revoke certificate for domain %s", domain)
+
+		certBytes, err := certsStorage.ReadFile(domain, ".crt")
+		if err != nil {
+			log.Fatalf("Error while revoking the certificate for domain %s\n\t%v", domain, err)
+		}
+
+		reason := ctx.Uint("reason")
+
+		err = client.Certificate.RevokeWithReason(certBytes, &reason)
+		if err != nil {
+			log.Fatalf("Error while revoking the certificate for domain %s\n\t%v", domain, err)
+		}
+
+		log.Println("Certificate was revoked.")
+
+		if ctx.Bool("keep") {
+			return nil
+		}
+
+		certsStorage.CreateArchiveFolder()
+
+		err = certsStorage.MoveToArchive(domain)
+		if err != nil {
+			return err
+		}
+
+		log.Println("Certificate was archived for domain:", domain)
+	}
+
+	return nil
+}

cmd/cmd_run.go

@@ -0,0 +1,222 @@
+package cmd
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+	"strings"
+	"time"
+
+	"github.com/go-acme/lego/v4/certificate"
+	"github.com/go-acme/lego/v4/lego"
+	"github.com/go-acme/lego/v4/log"
+	"github.com/go-acme/lego/v4/registration"
+	"github.com/urfave/cli/v2"
+)
+
+func createRun() *cli.Command {
+	return &cli.Command{
+		Name:  "run",
+		Usage: "Register an account, then create and install a certificate",
+		Before: func(ctx *cli.Context) error {
+			// we require either domains or csr, but not both
+			hasDomains := len(ctx.StringSlice("domains")) > 0
+			hasCsr := len(ctx.String("csr")) > 0
+			if hasDomains && hasCsr {
+				log.Fatal("Please specify either --domains/-d or --csr/-c, but not both")
+			}
+			if !hasDomains && !hasCsr {
+				log.Fatal("Please specify --domains/-d (or --csr/-c if you already have a CSR)")
+			}
+			return nil
+		},
+		Action: run,
+		Flags: []cli.Flag{
+			&cli.BoolFlag{
+				Name:  "no-bundle",
+				Usage: "Do not create a certificate bundle by adding the issuers certificate to the new certificate.",
+			},
+			&cli.BoolFlag{
+				Name: "must-staple",
+				Usage: "Include the OCSP must staple TLS extension in the CSR and generated certificate." +
+					" Only works if the CSR is generated by lego.",
+			},
+			&cli.TimestampFlag{
+				Name:   "not-before",
+				Usage:  "Set the notBefore field in the certificate (RFC3339 format)",
+				Layout: time.RFC3339,
+			},
+			&cli.TimestampFlag{
+				Name:   "not-after",
+				Usage:  "Set the notAfter field in the certificate (RFC3339 format)",
+				Layout: time.RFC3339,
+			},
+			&cli.StringFlag{
+				Name: "preferred-chain",
+				Usage: "If the CA offers multiple certificate chains, prefer the chain with an issuer matching this Subject Common Name." +
+					" If no match, the default offered chain will be used.",
+			},
+			&cli.StringFlag{
+				Name:  "always-deactivate-authorizations",
+				Usage: "Force the authorizations to be relinquished even if the certificate request was successful.",
+			},
+			&cli.StringFlag{
+				Name:  "run-hook",
+				Usage: "Define a hook. The hook is executed when the certificates are effectively created.",
+			},
+		},
+	}
+}
+
+const rootPathWarningMessage = `!!!! HEADS UP !!!!
+
+Your account credentials have been saved in your Let's Encrypt
+configuration directory at "%s".
+
+You should make a secure backup of this folder now. This
+configuration directory will also contain certificates and
+private keys obtained from Let's Encrypt so making regular
+backups of this folder is ideal.
+`
+
+func run(ctx *cli.Context) error {
+	accountsStorage := NewAccountsStorage(ctx)
+
+	account, client := setup(ctx, accountsStorage)
+	setupChallenges(ctx, client)
+
+	if account.Registration == nil {
+		reg, err := register(ctx, client)
+		if err != nil {
+			log.Fatalf("Could not complete registration\n\t%v", err)
+		}
+
+		account.Registration = reg
+		if err = accountsStorage.Save(account); err != nil {
+			log.Fatal(err)
+		}
+
+		fmt.Printf(rootPathWarningMessage, accountsStorage.GetRootPath())
+	}
+
+	certsStorage := NewCertificatesStorage(ctx)
+	certsStorage.CreateRootFolder()
+
+	cert, err := obtainCertificate(ctx, client)
+	if err != nil {
+		// Make sure to return a non-zero exit code if ObtainSANCertificate returned at least one error.
+		// Due to us not returning partial certificate we can just exit here instead of at the end.
+		log.Fatalf("Could not obtain certificates:\n\t%v", err)
+	}
+
+	certsStorage.SaveResource(cert)
+
+	meta := map[string]string{
+		renewEnvAccountEmail: account.Email,
+		renewEnvCertDomain:   cert.Domain,
+		renewEnvCertPath:     certsStorage.GetFileName(cert.Domain, ".crt"),
+		renewEnvCertKeyPath:  certsStorage.GetFileName(cert.Domain, ".key"),
+		renewEnvCertPEMPath:  certsStorage.GetFileName(cert.Domain, ".pem"),
+		renewEnvCertPFXPath:  certsStorage.GetFileName(cert.Domain, ".pfx"),
+	}
+
+	return launchHook(ctx.String("run-hook"), meta)
+}
+
+func handleTOS(ctx *cli.Context, client *lego.Client) bool {
+	// Check for a global accept override
+	if ctx.Bool("accept-tos") {
+		return true
+	}
+
+	reader := bufio.NewReader(os.Stdin)
+	log.Printf("Please review the TOS at %s", client.GetToSURL())
+
+	for {
+		fmt.Println("Do you accept the TOS? Y/n")
+		text, err := reader.ReadString('\n')
+		if err != nil {
+			log.Fatalf("Could not read from console: %v", err)
+		}
+
+		text = strings.Trim(text, "\r\n")
+		switch text {
+		case "", "y", "Y":
+			return true
+		case "n", "N":
+			return false
+		default:
+			fmt.Println("Your input was invalid. Please answer with one of Y/y, n/N or by pressing enter.")
+		}
+	}
+}
+
+func register(ctx *cli.Context, client *lego.Client) (*registration.Resource, error) {
+	accepted := handleTOS(ctx, client)
+	if !accepted {
+		log.Fatal("You did not accept the TOS. Unable to proceed.")
+	}
+
+	if ctx.Bool("eab") {
+		kid := ctx.String("kid")
+		hmacEncoded := ctx.String("hmac")
+
+		if kid == "" || hmacEncoded == "" {
+			log.Fatalf("Requires arguments --kid and --hmac.")
+		}
+
+		return client.Registration.RegisterWithExternalAccountBinding(registration.RegisterEABOptions{
+			TermsOfServiceAgreed: accepted,
+			Kid:                  kid,
+			HmacEncoded:          hmacEncoded,
+		})
+	}
+
+	return client.Registration.Register(registration.RegisterOptions{TermsOfServiceAgreed: true})
+}
+
+func obtainCertificate(ctx *cli.Context, client *lego.Client) (*certificate.Resource, error) {
+	bundle := !ctx.Bool("no-bundle")
+
+	domains := ctx.StringSlice("domains")
+	if len(domains) > 0 {
+		// obtain a certificate, generating a new private key
+		request := certificate.ObtainRequest{
+			Domains:                        domains,
+			Bundle:                         bundle,
+			MustStaple:                     ctx.Bool("must-staple"),
+			PreferredChain:                 ctx.String("preferred-chain"),
+			AlwaysDeactivateAuthorizations: ctx.Bool("always-deactivate-authorizations"),
+		}
+
+		notBefore := ctx.Timestamp("not-before")
+		if notBefore != nil {
+			request.NotBefore = *notBefore
+		}
+
+		notAfter := ctx.Timestamp("not-after")
+		if notAfter != nil {
+			request.NotAfter = *notAfter
+		}
+
+		return client.Certificate.Obtain(request)
+	}
+
+	// read the CSR
+	csr, err := readCSRFile(ctx.String("csr"))
+	if err != nil {
+		return nil, err
+	}
+
+	// obtain a certificate for this CSR
+	request := certificate.ObtainForCSRRequest{
+		CSR:                            csr,
+		NotBefore:                      getTime(ctx, "not-before"),
+		NotAfter:                       getTime(ctx, "not-after"),
+		Bundle:                         bundle,
+		PreferredChain:                 ctx.String("preferred-chain"),
+		AlwaysDeactivateAuthorizations: ctx.Bool("always-deactivate-authorizations"),
+	}
+
+	return client.Certificate.ObtainForCSR(request)
+}

cmd/flags.go

@@ -0,0 +1,170 @@
+package cmd
+
+import (
+	"time"
+
+	"github.com/go-acme/lego/v4/lego"
+	"github.com/urfave/cli/v2"
+	"software.sslmate.com/src/go-pkcs12"
+)
+
+func CreateFlags(defaultPath string) []cli.Flag {
+	return []cli.Flag{
+		&cli.StringSliceFlag{
+			Name:    "domains",
+			Aliases: []string{"d"},
+			Usage:   "Add a domain to the process. Can be specified multiple times.",
+		},
+		&cli.StringFlag{
+			Name:    "server",
+			Aliases: []string{"s"},
+			Usage:   "CA hostname (and optionally :port). The server certificate must be trusted in order to avoid further modifications to the client.",
+			Value:   lego.LEDirectoryProduction,
+		},
+		&cli.BoolFlag{
+			Name:    "accept-tos",
+			Aliases: []string{"a"},
+			Usage:   "By setting this flag to true you indicate that you accept the current Let's Encrypt terms of service.",
+		},
+		&cli.StringFlag{
+			Name:    "email",
+			Aliases: []string{"m"},
+			Usage:   "Email used for registration and recovery contact.",
+		},
+		&cli.StringFlag{
+			Name:    "csr",
+			Aliases: []string{"c"},
+			Usage:   "Certificate signing request filename, if an external CSR is to be used.",
+		},
+		&cli.BoolFlag{
+			Name:  "eab",
+			Usage: "Use External Account Binding for account registration. Requires --kid and --hmac.",
+		},
+		&cli.StringFlag{
+			Name:  "kid",
+			Usage: "Key identifier from External CA. Used for External Account Binding.",
+		},
+		&cli.StringFlag{
+			Name:  "hmac",
+			Usage: "MAC key from External CA. Should be in Base64 URL Encoding without padding format. Used for External Account Binding.",
+		},
+		&cli.StringFlag{
+			Name:    "key-type",
+			Aliases: []string{"k"},
+			Value:   "ec256",
+			Usage:   "Key type to use for private keys. Supported: rsa2048, rsa3072, rsa4096, rsa8192, ec256, ec384.",
+		},
+		&cli.StringFlag{
+			Name:  "filename",
+			Usage: "(deprecated) Filename of the generated certificate.",
+		},
+		&cli.StringFlag{
+			Name:    "path",
+			EnvVars: []string{"LEGO_PATH"},
+			Usage:   "Directory to use for storing the data.",
+			Value:   defaultPath,
+		},
+		&cli.BoolFlag{
+			Name:  "http",
+			Usage: "Use the HTTP-01 challenge to solve challenges. Can be mixed with other types of challenges.",
+		},
+		&cli.StringFlag{
+			Name:  "http.port",
+			Usage: "Set the port and interface to use for HTTP-01 based challenges to listen on. Supported: interface:port or :port.",
+			Value: ":80",
+		},
+		&cli.StringFlag{
+			Name:  "http.proxy-header",
+			Usage: "Validate against this HTTP header when solving HTTP-01 based challenges behind a reverse proxy.",
+			Value: "Host",
+		},
+		&cli.StringFlag{
+			Name: "http.webroot",
+			Usage: "Set the webroot folder to use for HTTP-01 based challenges to write directly to the .well-known/acme-challenge file." +
+				" This disables the built-in server and expects the given directory to be publicly served with access to .well-known/acme-challenge",
+		},
+		&cli.StringSliceFlag{
+			Name:  "http.memcached-host",
+			Usage: "Set the memcached host(s) to use for HTTP-01 based challenges. Challenges will be written to all specified hosts.",
+		},
+		&cli.BoolFlag{
+			Name:  "tls",
+			Usage: "Use the TLS-ALPN-01 challenge to solve challenges. Can be mixed with other types of challenges.",
+		},
+		&cli.StringFlag{
+			Name:  "tls.port",
+			Usage: "Set the port and interface to use for TLS-ALPN-01 based challenges to listen on. Supported: interface:port or :port.",
+			Value: ":443",
+		},
+		&cli.StringFlag{
+			Name:  "dns",
+			Usage: "Solve a DNS-01 challenge using the specified provider. Can be mixed with other types of challenges. Run 'lego dnshelp' for help on usage.",
+		},
+		&cli.BoolFlag{
+			Name:  "dns.disable-cp",
+			Usage: "By setting this flag to true, disables the need to await propagation of the TXT record to all authoritative name servers.",
+		},
+		&cli.StringSliceFlag{
+			Name: "dns.resolvers",
+			Usage: "Set the resolvers to use for performing (recursive) CNAME resolving and apex domain determination." +
+				" For DNS-01 challenge verification, the authoritative DNS server is queried directly." +
+				" Supported: host:port." +
+				" The default is to use the system resolvers, or Google's DNS resolvers if the system's cannot be determined.",
+		},
+		&cli.IntFlag{
+			Name:  "http-timeout",
+			Usage: "Set the HTTP timeout value to a specific value in seconds.",
+		},
+		&cli.IntFlag{
+			Name:  "dns-timeout",
+			Usage: "Set the DNS timeout value to a specific value in seconds. Used only when performing authoritative name server queries.",
+			Value: 10,
+		},
+		&cli.BoolFlag{
+			Name:  "pem",
+			Usage: "Generate an additional .pem (base64) file by concatenating the .key and .crt files together.",
+		},
+		&cli.BoolFlag{
+			Name:  "pfx",
+			Usage: "Generate an additional .pfx (PKCS#12) file by concatenating the .key and .crt and issuer .crt files together.",
+		},
+		&cli.StringFlag{
+			Name:  "pfx.pass",
+			Usage: "The password used to encrypt the .pfx (PCKS#12) file.",
+			Value: pkcs12.DefaultPassword,
+		},
+		&cli.IntFlag{
+			Name:  "cert.timeout",
+			Usage: "Set the certificate timeout value to a specific value in seconds. Only used when obtaining certificates.",
+			Value: 30,
+		},
+		&cli.StringFlag{
+			Name:  "user-agent",
+			Usage: "Add to the user-agent sent to the CA to identify an application embedding lego-cli",
+		},
+		&cli.StringFlag{
+			Name:  "nns",
+			Usage: "Solve a NNS-01 challenge using the specified URL of NNS server.",
+		},
+		&cli.StringFlag{
+			Name:  "wallet",
+			Usage: "Path to wallet file for NNS provider.",
+		},
+		&cli.StringFlag{
+			Name:  "wallet.account-address",
+			Usage: "Address of account to use from wallet file.",
+		},
+		&cli.StringFlag{
+			Name:  "wallet.password",
+			Usage: "Password to account from wallet file.",
+		},
+	}
+}
+
+func getTime(ctx *cli.Context, name string) time.Time {
+	value := ctx.Timestamp(name)
+	if value == nil {
+		return time.Time{}
+	}
+	return *value
+}

cmd/hook.go

@@ -0,0 +1,47 @@
+package cmd
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"os"
+	"os/exec"
+	"strings"
+	"time"
+)
+
+func launchHook(hook string, meta map[string]string) error {
+	if hook == "" {
+		return nil
+	}
+
+	ctxCmd, cancel := context.WithTimeout(context.Background(), 120*time.Second)
+	defer cancel()
+
+	parts := strings.Fields(hook)
+
+	cmdCtx := exec.CommandContext(ctxCmd, parts[0], parts[1:]...)
+	cmdCtx.Env = append(os.Environ(), metaToEnv(meta)...)
+
+	output, err := cmdCtx.CombinedOutput()
+
+	if len(output) > 0 {
+		fmt.Println(string(output))
+	}
+
+	if errors.Is(ctxCmd.Err(), context.DeadlineExceeded) {
+		return errors.New("hook timed out")
+	}
+
+	return err
+}
+
+func metaToEnv(meta map[string]string) []string {
+	var envs []string
+
+	for k, v := range meta {
+		envs = append(envs, k+"="+v)
+	}
+
+	return envs
+}

cmd/lego/main.go

@@ -0,0 +1,46 @@
+// Let's Encrypt client to go!
+// CLI application for generating Let's Encrypt certificates using the ACME package.
+package main
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"runtime"
+
+	"github.com/go-acme/lego/v4/cmd"
+	"github.com/go-acme/lego/v4/log"
+	"github.com/urfave/cli/v2"
+)
+
+var version = "dev"
+
+func main() {
+	app := cli.NewApp()
+	app.Name = "lego"
+	app.HelpName = "lego"
+	app.Usage = "Let's Encrypt client written in Go"
+	app.EnableBashCompletion = true
+
+	app.Version = version
+	cli.VersionPrinter = func(c *cli.Context) {
+		fmt.Printf("lego version %s %s/%s\n", c.App.Version, runtime.GOOS, runtime.GOARCH)
+	}
+
+	var defaultPath string
+	cwd, err := os.Getwd()
+	if err == nil {
+		defaultPath = filepath.Join(cwd, ".lego")
+	}
+
+	app.Flags = cmd.CreateFlags(defaultPath)
+
+	app.Before = cmd.Before
+
+	app.Commands = cmd.CreateCommands()
+
+	err = app.Run(os.Args)
+	if err != nil {
+		log.Fatal(err)
+	}
+}

cmd/setup.go

@@ -0,0 +1,134 @@
+package cmd
+
+import (
+	"crypto/x509"
+	"encoding/pem"
+	"fmt"
+	"os"
+	"strings"
+	"time"
+
+	"github.com/go-acme/lego/v4/certcrypto"
+	"github.com/go-acme/lego/v4/lego"
+	"github.com/go-acme/lego/v4/log"
+	"github.com/go-acme/lego/v4/registration"
+	"github.com/urfave/cli/v2"
+)
+
+const filePerm os.FileMode = 0o600
+
+func setup(ctx *cli.Context, accountsStorage *AccountsStorage) (*Account, *lego.Client) {
+	keyType := getKeyType(ctx)
+	privateKey := accountsStorage.GetPrivateKey(keyType)
+
+	var account *Account
+	if accountsStorage.ExistsAccountFilePath() {
+		account = accountsStorage.LoadAccount(privateKey)
+	} else {
+		account = &Account{Email: accountsStorage.GetUserID(), key: privateKey}
+	}
+
+	client := newClient(ctx, account, keyType)
+
+	return account, client
+}
+
+func newClient(ctx *cli.Context, acc registration.User, keyType certcrypto.KeyType) *lego.Client {
+	config := lego.NewConfig(acc)
+	config.CADirURL = ctx.String("server")
+
+	config.Certificate = lego.CertificateConfig{
+		KeyType: keyType,
+		Timeout: time.Duration(ctx.Int("cert.timeout")) * time.Second,
+	}
+	config.UserAgent = getUserAgent(ctx)
+
+	if ctx.IsSet("http-timeout") {
+		config.HTTPClient.Timeout = time.Duration(ctx.Int("http-timeout")) * time.Second
+	}
+
+	client, err := lego.NewClient(config)
+	if err != nil {
+		log.Fatalf("Could not create client: %v", err)
+	}
+
+	if client.GetExternalAccountRequired() && !ctx.IsSet("eab") {
+		log.Fatal("Server requires External Account Binding. Use --eab with --kid and --hmac.")
+	}
+
+	return client
+}
+
+// getKeyType the type from which private keys should be generated.
+func getKeyType(ctx *cli.Context) certcrypto.KeyType {
+	keyType := ctx.String("key-type")
+	switch strings.ToUpper(keyType) {
+	case "RSA2048":
+		return certcrypto.RSA2048
+	case "RSA3072":
+		return certcrypto.RSA3072
+	case "RSA4096":
+		return certcrypto.RSA4096
+	case "RSA8192":
+		return certcrypto.RSA8192
+	case "EC256":
+		return certcrypto.EC256
+	case "EC384":
+		return certcrypto.EC384
+	}
+
+	log.Fatalf("Unsupported KeyType: %s", keyType)
+	return ""
+}
+
+func getEmail(ctx *cli.Context) string {
+	email := ctx.String("email")
+	if email == "" {
+		log.Fatal("You have to pass an account (email address) to the program using --email or -m")
+	}
+	return email
+}
+
+func getUserAgent(ctx *cli.Context) string {
+	return strings.TrimSpace(fmt.Sprintf("%s lego-cli/%s", ctx.String("user-agent"), ctx.App.Version))
+}
+
+func createNonExistingFolder(path string) error {
+	if _, err := os.Stat(path); os.IsNotExist(err) {
+		return os.MkdirAll(path, 0o700)
+	} else if err != nil {
+		return err
+	}
+	return nil
+}
+
+func readCSRFile(filename string) (*x509.CertificateRequest, error) {
+	bytes, err := os.ReadFile(filename)
+	if err != nil {
+		return nil, err
+	}
+	raw := bytes
+
+	// see if we can find a PEM-encoded CSR
+	var p *pem.Block
+	rest := bytes
+	for {
+		// decode a PEM block
+		p, rest = pem.Decode(rest)
+
+		// did we fail?
+		if p == nil {
+			break
+		}
+
+		// did we get a CSR?
+		if p.Type == "CERTIFICATE REQUEST" || p.Type == "NEW CERTIFICATE REQUEST" {
+			raw = p.Bytes
+		}
+	}
+
+	// no PEM-encoded CSR
+	// assume we were given a DER-encoded ASN.1 CSR
+	// (if this assumption is wrong, parsing these bytes will fail)
+	return x509.ParseCertificateRequest(raw)
+}