Merge pull request #192 from smallstep/cloudkms-init

Cloudkms init

Makefile

@@ -1,5 +1,7 @@
 PKG?=github.com/smallstep/certificates/cmd/step-ca
 BINNAME?=step-ca
+CLOUDKMS_BINNAME?=step-cloudkms-init
+CLOUDKMS_PKG?=github.com/smallstep/certificates/cmd/step-cloudkms-init
 
 # Set V to 1 for verbose output from the Makefile
 Q=$(if $V,,@)
@@ -56,17 +58,22 @@ GOFLAGS := CGO_ENABLED=0
 download:
 	$Q go mod download
 
-build: $(PREFIX)bin/$(BINNAME)
+build: $(PREFIX)bin/$(BINNAME) $(PREFIX)bin/$(CLOUDKMS_BINNAME)
 	@echo "Build Complete!"
 
 $(PREFIX)bin/$(BINNAME): download $(call rwildcard,*.go)
 	$Q mkdir -p $(@D)
 	$Q $(GOOS_OVERRIDE) $(GOFLAGS) go build -v -o $(PREFIX)bin/$(BINNAME) $(LDFLAGS) $(PKG)
 
+$(PREFIX)bin/$(CLOUDKMS_BINNAME): download $(call rwildcard,*.go)
+	$Q mkdir -p $(@D)
+	$Q $(GOOS_OVERRIDE) $(GOFLAGS) go build -v -o $(PREFIX)bin/$(CLOUDKMS_BINNAME) $(LDFLAGS) $(CLOUDKMS_PKG)
+
 # Target to force a build of step-ca without running tests
 simple:
 	$Q mkdir -p $(PREFIX)bin
 	$Q $(GOOS_OVERRIDE) $(GOFLAGS) go build -v -o $(PREFIX)bin/$(BINNAME) $(LDFLAGS) $(PKG)
+	$Q $(GOOS_OVERRIDE) $(GOFLAGS) go build -v -o $(PREFIX)bin/$(CLOUDKMS_BINNAME) $(LDFLAGS) $(CLOUDKMS_PKG)
 	@echo "Build Complete!"
 
 .PHONY: download build simple
@@ -113,11 +120,13 @@ lint:
 
 INSTALL_PREFIX?=/usr/
 
-install: $(PREFIX)bin/$(BINNAME)
+install: $(PREFIX)bin/$(BINNAME) $(PREFIX)bin/$(CLOUDKMS_BINNAME)
 	$Q install -D $(PREFIX)bin/$(BINNAME) $(DESTDIR)$(INSTALL_PREFIX)bin/$(BINNAME)
+	$Q install -D $(PREFIX)bin/$(CLOUDKMS_BINNAME) $(DESTDIR)$(INSTALL_PREFIX)bin/$(CLOUDKMS_BINNAME)
 
 uninstall:
 	$Q rm -f $(DESTDIR)$(INSTALL_PREFIX)/bin/$(BINNAME)
+	$Q rm -f $(DESTDIR)$(INSTALL_PREFIX)/bin/$(CLOUDKMS_BINNAME)
 
 .PHONY: install uninstall
 
@@ -129,6 +138,9 @@ clean:
 ifneq ($(BINNAME),"")
 	$Q rm -f bin/$(BINNAME)
 endif
+ifneq ($(CLOUDKMS_BINNAME),"")
+	$Q rm -f bin/$(CLOUDKMS_BINNAME)
+endif
 
 .PHONY: clean
 
@@ -228,7 +240,7 @@ distclean: clean
 #################################################
 
 BINARY_OUTPUT=$(OUTPUT_ROOT)binary/
-BUNDLE_MAKE=v=$v GOOS_OVERRIDE='GOOS=$(1) GOARCH=$(2)' PREFIX=$(3) make $(3)bin/$(BINNAME)
+BUNDLE_MAKE=v=$v GOOS_OVERRIDE='GOOS=$(1) GOARCH=$(2)' PREFIX=$(3) make $(3)bin/$(BINNAME) $(3)bin/$(CLOUDKMS_BINNAME)
 RELEASE=./.travis-releases
 
 binary-linux:
@@ -246,6 +258,7 @@ define BUNDLE
 	newdir=$$TMP/$$stepName; \
 	mkdir -p $$newdir/bin; \
 	cp $(BINARY_OUTPUT)$(1)/bin/$(BINNAME) $$newdir/bin/; \
+	cp $(BINARY_OUTPUT)$(1)/bin/$(CLOUDKMS_BINNAME) $$newdir/bin/; \
 	cp README.md $$newdir/; \
 	NEW_BUNDLE=$(RELEASE)/step-certificates_$(2)_$(1)_$(3).tar.gz; \
 	rm -f $$NEW_BUNDLE; \

cmd/step-cloudkms-init/main.go

@@ -0,0 +1,273 @@
+package main
+
+import (
+	"context"
+	"crypto"
+	"crypto/rand"
+	"crypto/sha1"
+	"crypto/x509"
+	"crypto/x509/pkix"
+	"encoding/pem"
+	"flag"
+	"fmt"
+	"math/big"
+	"os"
+	"strings"
+	"time"
+
+	"github.com/smallstep/certificates/kms/apiv1"
+	"github.com/smallstep/certificates/kms/cloudkms"
+	"github.com/smallstep/cli/crypto/pemutil"
+	"github.com/smallstep/cli/ui"
+	"github.com/smallstep/cli/utils"
+	"golang.org/x/crypto/ssh"
+)
+
+func main() {
+	var credentialsFile string
+	var project, location, ring string
+	var protectionLevelName string
+	var ssh bool
+	flag.StringVar(&credentialsFile, "credentials-file", "", "Path to the `file` containing the Google's Cloud KMS credentials.")
+	flag.StringVar(&project, "project", "", "Google Cloud Project ID.")
+	flag.StringVar(&location, "location", "global", "Cloud KMS location name.")
+	flag.StringVar(&ring, "ring", "pki", "Cloud KMS ring name.")
+	flag.StringVar(&protectionLevelName, "protection-level", "SOFTWARE", "Protection level to use, SOFTWARE or HSM.")
+	flag.BoolVar(&ssh, "ssh", false, "Create SSH keys.")
+	flag.Usage = usage
+	flag.Parse()
+
+	switch {
+	case project == "":
+		usage()
+	case location == "":
+		fmt.Fprintln(os.Stderr, "flag `--location` is required")
+		os.Exit(1)
+	case ring == "":
+		fmt.Fprintln(os.Stderr, "flag `--ring` is required")
+		os.Exit(1)
+	case protectionLevelName == "":
+		fmt.Fprintln(os.Stderr, "flag `--protection-level` is required")
+		os.Exit(1)
+	}
+
+	var protectionLevel apiv1.ProtectionLevel
+	switch strings.ToUpper(protectionLevelName) {
+	case "SOFTWARE":
+		protectionLevel = apiv1.Software
+	case "HSM":
+		protectionLevel = apiv1.HSM
+	default:
+		fmt.Fprintf(os.Stderr, "invalid value `%s` for flag `--protection-level`; options are `SOFTWARE` or `HSM`\n", protectionLevelName)
+		os.Exit(1)
+	}
+
+	c, err := cloudkms.New(context.Background(), apiv1.Options{
+		Type:            string(apiv1.CloudKMS),
+		CredentialsFile: credentialsFile,
+	})
+	if err != nil {
+		fatal(err)
+	}
+
+	if err := createPKI(c, project, location, ring, protectionLevel); err != nil {
+		fatal(err)
+	}
+
+	if ssh {
+		ui.Println()
+		if err := createSSH(c, project, location, ring, protectionLevel); err != nil {
+			fatal(err)
+		}
+	}
+}
+
+func fatal(err error) {
+	fmt.Fprintln(os.Stderr, err)
+	os.Exit(1)
+}
+
+func usage() {
+	fmt.Fprintln(os.Stderr, "Usage: step-cloudkms-init --project <name>")
+	fmt.Fprintln(os.Stderr, `
+The step-cloudkms-init command initializes a public key infrastructure (PKI)
+to be used by step-ca.
+
+This tool is experimental and in the future it will be integrated in step cli.
+
+OPTIONS`)
+	fmt.Fprintln(os.Stderr)
+	flag.PrintDefaults()
+	fmt.Fprintln(os.Stderr, `
+COPYRIGHT
+
+  (c) 2018-2020 Smallstep Labs, Inc.`)
+	os.Exit(1)
+}
+
+func createPKI(c *cloudkms.CloudKMS, project, location, keyRing string, protectionLevel apiv1.ProtectionLevel) error {
+	ui.Println("Creating PKI ...")
+
+	parent := "projects/" + project + "/locations/" + location + "/keyRings/" + keyRing + "/cryptoKeys"
+
+	// Root Certificate
+	resp, err := c.CreateKey(&apiv1.CreateKeyRequest{
+		Name:               parent + "/root",
+		SignatureAlgorithm: apiv1.ECDSAWithSHA256,
+		ProtectionLevel:    protectionLevel,
+	})
+	if err != nil {
+		return err
+	}
+
+	signer, err := c.CreateSigner(&resp.CreateSignerRequest)
+	if err != nil {
+		return err
+	}
+
+	now := time.Now()
+	root := &x509.Certificate{
+		IsCA:                  true,
+		NotBefore:             now,
+		NotAfter:              now.Add(time.Hour * 24 * 365 * 10),
+		KeyUsage:              x509.KeyUsageCertSign | x509.KeyUsageCRLSign,
+		BasicConstraintsValid: true,
+		MaxPathLen:            1,
+		MaxPathLenZero:        false,
+		Issuer:                pkix.Name{CommonName: "Smallstep Root"},
+		Subject:               pkix.Name{CommonName: "Smallstep Root"},
+		SerialNumber:          mustSerialNumber(),
+		SubjectKeyId:          mustSubjectKeyID(resp.PublicKey),
+	}
+
+	b, err := x509.CreateCertificate(rand.Reader, root, root, resp.PublicKey, signer)
+	if err != nil {
+		return err
+	}
+
+	if err = utils.WriteFile("root_ca.crt", pem.EncodeToMemory(&pem.Block{
+		Type:  "CERTIFICATE",
+		Bytes: b,
+	}), 0600); err != nil {
+		return err
+	}
+
+	ui.PrintSelected("Root Key", resp.Name)
+	ui.PrintSelected("Root Certificate", "root_ca.crt")
+
+	root, err = pemutil.ReadCertificate("root_ca.crt")
+	if err != nil {
+		return err
+	}
+
+	// Intermediate Certificate
+	resp, err = c.CreateKey(&apiv1.CreateKeyRequest{
+		Name:               parent + "/intermediate",
+		SignatureAlgorithm: apiv1.ECDSAWithSHA256,
+		ProtectionLevel:    protectionLevel,
+	})
+	if err != nil {
+		return err
+	}
+
+	intermediate := &x509.Certificate{
+		IsCA:                  true,
+		NotBefore:             now,
+		NotAfter:              now.Add(time.Hour * 24 * 365 * 10),
+		KeyUsage:              x509.KeyUsageCertSign | x509.KeyUsageCRLSign,
+		BasicConstraintsValid: true,
+		MaxPathLen:            0,
+		MaxPathLenZero:        true,
+		Issuer:                root.Subject,
+		Subject:               pkix.Name{CommonName: "Smallstep Intermediate"},
+		SerialNumber:          mustSerialNumber(),
+		SubjectKeyId:          mustSubjectKeyID(resp.PublicKey),
+	}
+
+	b, err = x509.CreateCertificate(rand.Reader, intermediate, root, resp.PublicKey, signer)
+	if err != nil {
+		return err
+	}
+
+	if err = utils.WriteFile("intermediate_ca.crt", pem.EncodeToMemory(&pem.Block{
+		Type:  "CERTIFICATE",
+		Bytes: b,
+	}), 0600); err != nil {
+		return err
+	}
+
+	ui.PrintSelected("Intermediate Key", resp.Name)
+	ui.PrintSelected("Intermediate Certificate", "intermediate_ca.crt")
+
+	return nil
+}
+
+func createSSH(c *cloudkms.CloudKMS, project, location, keyRing string, protectionLevel apiv1.ProtectionLevel) error {
+	ui.Println("Creating SSH Keys ...")
+
+	parent := "projects/" + project + "/locations/" + location + "/keyRings/" + keyRing + "/cryptoKeys"
+
+	// User Key
+	resp, err := c.CreateKey(&apiv1.CreateKeyRequest{
+		Name:               parent + "/ssh-user-key",
+		SignatureAlgorithm: apiv1.ECDSAWithSHA256,
+		ProtectionLevel:    protectionLevel,
+	})
+	if err != nil {
+		return err
+	}
+
+	key, err := ssh.NewPublicKey(resp.PublicKey)
+	if err != nil {
+		return err
+	}
+
+	if err = utils.WriteFile("ssh_user_ca_key.pub", ssh.MarshalAuthorizedKey(key), 0600); err != nil {
+		return err
+	}
+
+	ui.PrintSelected("SSH User Public Key", "ssh_user_ca_key.pub")
+	ui.PrintSelected("SSH User Private Key", resp.Name)
+
+	// Host Key
+	resp, err = c.CreateKey(&apiv1.CreateKeyRequest{
+		Name:               parent + "/ssh-host-key",
+		SignatureAlgorithm: apiv1.ECDSAWithSHA256,
+		ProtectionLevel:    apiv1.Software,
+	})
+	if err != nil {
+		return err
+	}
+
+	key, err = ssh.NewPublicKey(resp.PublicKey)
+	if err != nil {
+		return err
+	}
+
+	if err = utils.WriteFile("ssh_host_ca_key.pub", ssh.MarshalAuthorizedKey(key), 0600); err != nil {
+		return err
+	}
+
+	ui.PrintSelected("SSH Host Public Key", "ssh_host_ca_key.pub")
+	ui.PrintSelected("SSH Host Private Key", resp.Name)
+
+	return nil
+}
+
+func mustSerialNumber() *big.Int {
+	serialNumberLimit := new(big.Int).Lsh(big.NewInt(1), 128)
+	sn, err := rand.Int(rand.Reader, serialNumberLimit)
+	if err != nil {
+		panic(err)
+	}
+	return sn
+}
+
+func mustSubjectKeyID(key crypto.PublicKey) []byte {
+	b, err := x509.MarshalPKIXPublicKey(key)
+	if err != nil {
+		panic(err)
+	}
+	hash := sha1.Sum(b)
+	return hash[:]
+}

docs/kms.md

@@ -0,0 +1,67 @@
+# Key Management Services
+
+This document describes how to use a key management service or KMS to store the
+private keys and sign certificates.
+
+Support for multiple KMS are planned, but currently the only supported one is
+Google's Cloud KMS.
+
+## Google's Cloud KMS.
+
+[Cloud KMS](https://cloud.google.com/kms) is the Google's cloud-hosted KMS that
+allows you to store the cryptographic keys, and sign certificates using their
+infrastructure. Cloud KMS supports two different protection levels, SOFTWARE and
+HSM.
+
+To configure Cloud KMS in your CA you need add the `"kms"` property to you
+`ca.json`, and replace the property`"key"` with the Cloud KMS key name of your
+intermediate key:
+
+```json
+{
+    ...
+    "key": "projects/<project-id>/locations/global/keyRings/<ring-id>/cryptoKeys/<key-id>/cryptoKeyVersions/<version-number>",
+    ...
+    "kms": {
+        "type": "cloudkms",
+        "credentialsFile": "path/to/credentials.json"
+    }
+}
+```
+
+In a similar way, for SSH certificate, the SSH keys must be Cloud KMS names:
+
+```json
+{
+    ...
+    "ssh": {
+        "hostKey": "projects/<project-id>/locations/global/keyRings/<ring-id>/cryptoKeys/<key-id>/cryptoKeyVersions/<version-number>",
+        "userKey": "projects/<project-id>/locations/global/keyRings/<ring-id>/cryptoKeys/<key-id>/cryptoKeyVersions/<version-number>"
+    },
+}
+```
+
+Currently [step](https://github.com/smallstep/cli) does not provide an automatic
+way to initialize the public key infrastructure (PKI) using Cloud KMS, but an
+experimental tool named `step-cloudkms-init` is available for this use case. At
+some point this tool will be integrated into `step` and it will be deleted.
+
+To use `step-cloudkms-init` just enable Cloud KMS in your project and run:
+
+```sh
+$ export GOOGLE_APPLICATION_CREDENTIALS=/path/to/credentials.json
+$ step-cloudkms-init --project your-project-id --ssh
+Creating PKI ...
+✔ Root Key: projects/your-project-id/locations/global/keyRings/pki/cryptoKeys/root/cryptoKeyVersions/1
+✔ Root Certificate: root_ca.crt
+✔ Intermediate Key: projects/your-project-id/locations/global/keyRings/pki/cryptoKeys/intermediate/cryptoKeyVersions/1
+✔ Intermediate Certificate: intermediate_ca.crt
+
+Creating SSH Keys ...
+✔ SSH User Public Key: ssh_user_ca_key.pub
+✔ SSH User Private Key: projects/your-project-id/locations/global/keyRings/pki/cryptoKeys/ssh-user-key/cryptoKeyVersions/1
+✔ SSH Host Public Key: ssh_host_ca_key.pub
+✔ SSH Host Private Key: projects/your-project-id/locations/global/keyRings/pki/cryptoKeys/ssh-host-key/cryptoKeyVersions/1
+```
+
+See `step-cloudkms-init --help` for more options.