Merge branch 'master' into herman/ip-sans-improvements

CHANGELOG.md

@@ -6,6 +6,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 ## [Unreleased - 0.18.1] - DATE
 ### Added
+- Support for ACME revocation.
 ### Changed
 ### Deprecated
 ### Removed

README.md

@@ -42,6 +42,8 @@ To get up and running quickly, or as an alternative to running your own `step-ca
 [![GitHub stars](https://img.shields.io/github/stars/smallstep/certificates.svg?style=social)](https://github.com/smallstep/certificates/stargazers)
 [![Twitter followers](https://img.shields.io/twitter/follow/smallsteplabs.svg?label=Follow&style=social)](https://twitter.com/intent/follow?screen_name=smallsteplabs)
 
+![star us](https://github.com/smallstep/certificates/raw/master/docs/images/star.gif)
+
 ## Features
 
 ### 🦾 A fast, stable, flexible private CA

acme/api/handler.go

@@ -100,11 +100,17 @@ func (h *Handler) Route(r api.Router) {
 	r.MethodFunc("GET", getPath(DirectoryLinkType, "{provisionerID}"), h.baseURLFromRequest(h.lookupProvisioner(h.GetDirectory)))
 	r.MethodFunc("HEAD", getPath(DirectoryLinkType, "{provisionerID}"), h.baseURLFromRequest(h.lookupProvisioner(h.GetDirectory)))
 
+	validatingMiddleware := func(next nextHTTP) nextHTTP {
+		return h.baseURLFromRequest(h.lookupProvisioner(h.addNonce(h.addDirLink(h.verifyContentType(h.parseJWS(h.validateJWS(next)))))))
+	}
 	extractPayloadByJWK := func(next nextHTTP) nextHTTP {
-		return h.baseURLFromRequest(h.lookupProvisioner(h.addNonce(h.addDirLink(h.verifyContentType(h.parseJWS(h.validateJWS(h.extractJWK(h.verifyAndExtractJWSPayload(next)))))))))
+		return validatingMiddleware(h.extractJWK(h.verifyAndExtractJWSPayload(next)))
 	}
 	extractPayloadByKid := func(next nextHTTP) nextHTTP {
-		return h.baseURLFromRequest(h.lookupProvisioner(h.addNonce(h.addDirLink(h.verifyContentType(h.parseJWS(h.validateJWS(h.lookupJWK(h.verifyAndExtractJWSPayload(next)))))))))
+		return validatingMiddleware(h.lookupJWK(h.verifyAndExtractJWSPayload(next)))
+	}
+	extractPayloadByKidOrJWK := func(next nextHTTP) nextHTTP {
+		return validatingMiddleware(h.extractOrLookupJWK(h.verifyAndExtractJWSPayload(next)))
 	}
 
 	r.MethodFunc("POST", getPath(NewAccountLinkType, "{provisionerID}"), extractPayloadByJWK(h.NewAccount))
@@ -117,6 +123,7 @@ func (h *Handler) Route(r api.Router) {
 	r.MethodFunc("POST", getPath(AuthzLinkType, "{provisionerID}", "{authzID}"), extractPayloadByKid(h.isPostAsGet(h.GetAuthorization)))
 	r.MethodFunc("POST", getPath(ChallengeLinkType, "{provisionerID}", "{authzID}", "{chID}"), extractPayloadByKid(h.GetChallenge))
 	r.MethodFunc("POST", getPath(CertificateLinkType, "{provisionerID}", "{certID}"), extractPayloadByKid(h.isPostAsGet(h.GetCertificate)))
+	r.MethodFunc("POST", getPath(RevokeCertLinkType, "{provisionerID}"), extractPayloadByKidOrJWK(h.RevokeCert))
 }
 
 // GetNonce just sets the right header since a Nonce is added to each response

acme/api/middleware.go

@@ -262,11 +262,11 @@ func (h *Handler) extractJWK(next nextHTTP) nextHTTP {
 		// Store the JWK in the context.
 		ctx = context.WithValue(ctx, jwkContextKey, jwk)
 
-		// Get Account or continue to generate a new one.
+		// Get Account OR continue to generate a new one OR continue Revoke with certificate private key
 		acc, err := h.db.GetAccountByKeyID(ctx, jwk.KeyID)
 		switch {
 		case errors.Is(err, acme.ErrNotFound):
-			// For NewAccount requests ...
+			// For NewAccount and Revoke requests ...
 			break
 		case err != nil:
 			api.WriteError(w, err)
@@ -352,6 +352,42 @@ func (h *Handler) lookupJWK(next nextHTTP) nextHTTP {
 	}
 }
 
+// extractOrLookupJWK forwards handling to either extractJWK or
+// lookupJWK based on the presence of a JWK or a KID, respectively.
+func (h *Handler) extractOrLookupJWK(next nextHTTP) nextHTTP {
+	return func(w http.ResponseWriter, r *http.Request) {
+		ctx := r.Context()
+		jws, err := jwsFromContext(ctx)
+		if err != nil {
+			api.WriteError(w, err)
+			return
+		}
+
+		// at this point the JWS has already been verified (if correctly configured in middleware),
+		// and it can be used to check if a JWK exists. This flow is used when the ACME client
+		// signed the payload with a certificate private key.
+		if canExtractJWKFrom(jws) {
+			h.extractJWK(next)(w, r)
+			return
+		}
+
+		// default to looking up the JWK based on KeyID. This flow is used when the ACME client
+		// signed the payload with an account private key.
+		h.lookupJWK(next)(w, r)
+	}
+}
+
+// canExtractJWKFrom checks if the JWS has a JWK that can be extracted
+func canExtractJWKFrom(jws *jose.JSONWebSignature) bool {
+	if jws == nil {
+		return false
+	}
+	if len(jws.Signatures) == 0 {
+		return false
+	}
+	return jws.Signatures[0].Protected.JSONWebKey != nil
+}
+
 // verifyAndExtractJWSPayload extracts the JWK from the JWS and saves it in the context.
 // Make sure to parse and validate the JWS before running this middleware.
 func (h *Handler) verifyAndExtractJWSPayload(next nextHTTP) nextHTTP {

acme/api/middleware_test.go

@@ -1472,3 +1472,187 @@ func TestHandler_validateJWS(t *testing.T) {
 		})
 	}
 }
+
+func Test_canExtractJWKFrom(t *testing.T) {
+	jwk, err := jose.GenerateJWK("EC", "P-256", "ES256", "sig", "", 0)
+	assert.FatalError(t, err)
+	type args struct {
+		jws *jose.JSONWebSignature
+	}
+	tests := []struct {
+		name string
+		args args
+		want bool
+	}{
+		{
+			name: "no-jws",
+			args: args{
+				jws: nil,
+			},
+			want: false,
+		},
+		{
+			name: "no-signatures",
+			args: args{
+				jws: &jose.JSONWebSignature{
+					Signatures: []jose.Signature{},
+				},
+			},
+			want: false,
+		},
+		{
+			name: "no-jwk",
+			args: args{
+				jws: &jose.JSONWebSignature{
+					Signatures: []jose.Signature{
+						{
+							Protected: jose.Header{},
+						},
+					},
+				},
+			},
+			want: false,
+		},
+		{
+			name: "ok",
+			args: args{
+				jws: &jose.JSONWebSignature{
+					Signatures: []jose.Signature{
+						{
+							Protected: jose.Header{
+								JSONWebKey: jwk,
+							},
+						},
+					},
+				},
+			},
+			want: true,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := canExtractJWKFrom(tt.args.jws); got != tt.want {
+				t.Errorf("canExtractJWKFrom() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestHandler_extractOrLookupJWK(t *testing.T) {
+	u := "https://ca.smallstep.com/acme/account"
+	type test struct {
+		db         acme.DB
+		linker     Linker
+		statusCode int
+		ctx        context.Context
+		err        *acme.Error
+		next       func(w http.ResponseWriter, r *http.Request)
+	}
+	var tests = map[string]func(t *testing.T) test{
+		"ok/extract": func(t *testing.T) test {
+			jwk, err := jose.GenerateJWK("EC", "P-256", "ES256", "sig", "", 0)
+			assert.FatalError(t, err)
+			kid, err := jwk.Thumbprint(crypto.SHA256)
+			assert.FatalError(t, err)
+			pub := jwk.Public()
+			pub.KeyID = base64.RawURLEncoding.EncodeToString(kid)
+			so := new(jose.SignerOptions)
+			so.WithHeader("jwk", pub) // JWK for certificate private key flow
+			signer, err := jose.NewSigner(jose.SigningKey{
+				Algorithm: jose.SignatureAlgorithm(jwk.Algorithm),
+				Key:       jwk.Key,
+			}, so)
+			assert.FatalError(t, err)
+			signed, err := signer.Sign([]byte("foo"))
+			assert.FatalError(t, err)
+			raw, err := signed.CompactSerialize()
+			assert.FatalError(t, err)
+			parsedJWS, err := jose.ParseJWS(raw)
+			assert.FatalError(t, err)
+			return test{
+				linker: NewLinker("dns", "acme"),
+				db: &acme.MockDB{
+					MockGetAccountByKeyID: func(ctx context.Context, kid string) (*acme.Account, error) {
+						assert.Equals(t, kid, pub.KeyID)
+						return nil, acme.ErrNotFound
+					},
+				},
+				ctx:        context.WithValue(context.Background(), jwsContextKey, parsedJWS),
+				statusCode: 200,
+				next: func(w http.ResponseWriter, r *http.Request) {
+					w.Write(testBody)
+				},
+			}
+		},
+		"ok/lookup": func(t *testing.T) test {
+			prov := newProv()
+			provName := url.PathEscape(prov.GetName())
+			baseURL := &url.URL{Scheme: "https", Host: "test.ca.smallstep.com"}
+			jwk, err := jose.GenerateJWK("EC", "P-256", "ES256", "sig", "", 0)
+			assert.FatalError(t, err)
+			accID := "accID"
+			prefix := fmt.Sprintf("%s/acme/%s/account/", baseURL, provName)
+			so := new(jose.SignerOptions)
+			so.WithHeader("kid", fmt.Sprintf("%s%s", prefix, accID)) // KID for account private key flow
+			signer, err := jose.NewSigner(jose.SigningKey{
+				Algorithm: jose.SignatureAlgorithm(jwk.Algorithm),
+				Key:       jwk.Key,
+			}, so)
+			assert.FatalError(t, err)
+			jws, err := signer.Sign([]byte("baz"))
+			assert.FatalError(t, err)
+			raw, err := jws.CompactSerialize()
+			assert.FatalError(t, err)
+			parsedJWS, err := jose.ParseJWS(raw)
+			assert.FatalError(t, err)
+			acc := &acme.Account{ID: "accID", Key: jwk, Status: "valid"}
+			ctx := context.WithValue(context.Background(), provisionerContextKey, prov)
+			ctx = context.WithValue(ctx, baseURLContextKey, baseURL)
+			ctx = context.WithValue(ctx, jwsContextKey, parsedJWS)
+			return test{
+				linker: NewLinker("test.ca.smallstep.com", "acme"),
+				db: &acme.MockDB{
+					MockGetAccount: func(ctx context.Context, accID string) (*acme.Account, error) {
+						assert.Equals(t, accID, acc.ID)
+						return acc, nil
+					},
+				},
+				ctx:        ctx,
+				statusCode: 200,
+				next: func(w http.ResponseWriter, r *http.Request) {
+					w.Write(testBody)
+				},
+			}
+		},
+	}
+	for name, prep := range tests {
+		tc := prep(t)
+		t.Run(name, func(t *testing.T) {
+			h := &Handler{db: tc.db, linker: tc.linker}
+			req := httptest.NewRequest("GET", u, nil)
+			req = req.WithContext(tc.ctx)
+			w := httptest.NewRecorder()
+			h.extractOrLookupJWK(tc.next)(w, req)
+			res := w.Result()
+
+			assert.Equals(t, res.StatusCode, tc.statusCode)
+
+			body, err := io.ReadAll(res.Body)
+			res.Body.Close()
+			assert.FatalError(t, err)
+
+			if res.StatusCode >= 400 && assert.NotNil(t, tc.err) {
+				var ae acme.Error
+				assert.FatalError(t, json.Unmarshal(bytes.TrimSpace(body), &ae))
+
+				assert.Equals(t, ae.Type, tc.err.Type)
+				assert.Equals(t, ae.Detail, tc.err.Detail)
+				assert.Equals(t, ae.Identifier, tc.err.Identifier)
+				assert.Equals(t, ae.Subproblems, tc.err.Subproblems)
+				assert.Equals(t, res.Header["Content-Type"], []string{"application/problem+json"})
+			} else {
+				assert.Equals(t, bytes.TrimSpace(body), testBody)
+			}
+		})
+	}
+}

acme/api/revoke.go

@@ -0,0 +1,287 @@
+package api
+
+import (
+	"bytes"
+	"context"
+	"crypto/x509"
+	"encoding/base64"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"strings"
+
+	"github.com/smallstep/certificates/acme"
+	"github.com/smallstep/certificates/api"
+	"github.com/smallstep/certificates/authority"
+	"github.com/smallstep/certificates/authority/provisioner"
+	"github.com/smallstep/certificates/logging"
+	"go.step.sm/crypto/jose"
+	"golang.org/x/crypto/ocsp"
+)
+
+type revokePayload struct {
+	Certificate string `json:"certificate"`
+	ReasonCode  *int   `json:"reason,omitempty"`
+}
+
+// RevokeCert attempts to revoke a certificate.
+func (h *Handler) RevokeCert(w http.ResponseWriter, r *http.Request) {
+
+	ctx := r.Context()
+	jws, err := jwsFromContext(ctx)
+	if err != nil {
+		api.WriteError(w, err)
+		return
+	}
+
+	prov, err := provisionerFromContext(ctx)
+	if err != nil {
+		api.WriteError(w, err)
+		return
+	}
+
+	payload, err := payloadFromContext(ctx)
+	if err != nil {
+		api.WriteError(w, err)
+		return
+	}
+
+	var p revokePayload
+	err = json.Unmarshal(payload.value, &p)
+	if err != nil {
+		api.WriteError(w, acme.WrapErrorISE(err, "error unmarshaling payload"))
+		return
+	}
+
+	certBytes, err := base64.RawURLEncoding.DecodeString(p.Certificate)
+	if err != nil {
+		// in this case the most likely cause is a client that didn't properly encode the certificate
+		api.WriteError(w, acme.WrapError(acme.ErrorMalformedType, err, "error base64url decoding payload certificate property"))
+		return
+	}
+
+	certToBeRevoked, err := x509.ParseCertificate(certBytes)
+	if err != nil {
+		// in this case a client may have encoded something different than a certificate
+		api.WriteError(w, acme.WrapError(acme.ErrorMalformedType, err, "error parsing certificate"))
+		return
+	}
+
+	serial := certToBeRevoked.SerialNumber.String()
+	dbCert, err := h.db.GetCertificateBySerial(ctx, serial)
+	if err != nil {
+		api.WriteError(w, acme.WrapErrorISE(err, "error retrieving certificate by serial"))
+		return
+	}
+
+	if !bytes.Equal(dbCert.Leaf.Raw, certToBeRevoked.Raw) {
+		// this should never happen
+		api.WriteError(w, acme.NewErrorISE("certificate raw bytes are not equal"))
+		return
+	}
+
+	if shouldCheckAccountFrom(jws) {
+		account, err := accountFromContext(ctx)
+		if err != nil {
+			api.WriteError(w, err)
+			return
+		}
+		acmeErr := h.isAccountAuthorized(ctx, dbCert, certToBeRevoked, account)
+		if acmeErr != nil {
+			api.WriteError(w, acmeErr)
+			return
+		}
+	} else {
+		// if account doesn't need to be checked, the JWS should be verified to be signed by the
+		// private key that belongs to the public key in the certificate to be revoked.
+		_, err := jws.Verify(certToBeRevoked.PublicKey)
+		if err != nil {
+			// TODO(hs): possible to determine an error vs. unauthorized and thus provide an ISE vs. Unauthorized?
+			api.WriteError(w, wrapUnauthorizedError(certToBeRevoked, nil, "verification of jws using certificate public key failed", err))
+			return
+		}
+	}
+
+	hasBeenRevokedBefore, err := h.ca.IsRevoked(serial)
+	if err != nil {
+		api.WriteError(w, acme.WrapErrorISE(err, "error retrieving revocation status of certificate"))
+		return
+	}
+
+	if hasBeenRevokedBefore {
+		api.WriteError(w, acme.NewError(acme.ErrorAlreadyRevokedType, "certificate was already revoked"))
+		return
+	}
+
+	reasonCode := p.ReasonCode
+	acmeErr := validateReasonCode(reasonCode)
+	if acmeErr != nil {
+		api.WriteError(w, acmeErr)
+		return
+	}
+
+	// Authorize revocation by ACME provisioner
+	ctx = provisioner.NewContextWithMethod(ctx, provisioner.RevokeMethod)
+	err = prov.AuthorizeRevoke(ctx, "")
+	if err != nil {
+		api.WriteError(w, acme.WrapErrorISE(err, "error authorizing revocation on provisioner"))
+		return
+	}
+
+	options := revokeOptions(serial, certToBeRevoked, reasonCode)
+	err = h.ca.Revoke(ctx, options)
+	if err != nil {
+		api.WriteError(w, wrapRevokeErr(err))
+		return
+	}
+
+	logRevoke(w, options)
+	w.Header().Add("Link", link(h.linker.GetLink(ctx, DirectoryLinkType), "index"))
+	w.Write(nil)
+}
+
+// isAccountAuthorized checks if an ACME account that was retrieved earlier is authorized
+// to revoke the certificate. An Account must always be valid in order to revoke a certificate.
+// In case the certificate retrieved from the database belongs to the Account, the Account is
+// authorized. If the certificate retrieved from the database doesn't belong to the Account,
+// the identifiers in the certificate are extracted and compared against the (valid) Authorizations
+// that are stored for the ACME Account. If these sets match, the Account is considered authorized
+// to revoke the certificate. If this check fails, the client will receive an unauthorized error.
+func (h *Handler) isAccountAuthorized(ctx context.Context, dbCert *acme.Certificate, certToBeRevoked *x509.Certificate, account *acme.Account) *acme.Error {
+	if !account.IsValid() {
+		return wrapUnauthorizedError(certToBeRevoked, nil, fmt.Sprintf("account '%s' has status '%s'", account.ID, account.Status), nil)
+	}
+	certificateBelongsToAccount := dbCert.AccountID == account.ID
+	if certificateBelongsToAccount {
+		return nil // return early
+	}
+
+	// TODO(hs): according to RFC8555: 7.6, a server MUST consider the following accounts authorized
+	// to revoke a certificate:
+	//
+	//	o  the account that issued the certificate.
+	//	o  an account that holds authorizations for all of the identifiers in the certificate.
+	//
+	// We currently only support the first case. The second might result in step going OOM when
+	// large numbers of Authorizations are involved when the current nosql interface is in use.
+	// We want to protect users from this failure scenario, so that's why it hasn't been added yet.
+	// This issue is tracked in https://github.com/smallstep/certificates/issues/767
+
+	// not authorized; fail closed.
+	return wrapUnauthorizedError(certToBeRevoked, nil, fmt.Sprintf("account '%s' is not authorized", account.ID), nil)
+}
+
+// wrapRevokeErr is a best effort implementation to transform an error during
+// revocation into an ACME error, so that clients can understand the error.
+func wrapRevokeErr(err error) *acme.Error {
+	t := err.Error()
+	if strings.Contains(t, "is already revoked") {
+		return acme.NewError(acme.ErrorAlreadyRevokedType, t)
+	}
+	return acme.WrapErrorISE(err, "error when revoking certificate")
+}
+
+// unauthorizedError returns an ACME error indicating the request was
+// not authorized to revoke the certificate.
+func wrapUnauthorizedError(cert *x509.Certificate, unauthorizedIdentifiers []acme.Identifier, msg string, err error) *acme.Error {
+	var acmeErr *acme.Error
+	if err == nil {
+		acmeErr = acme.NewError(acme.ErrorUnauthorizedType, msg)
+	} else {
+		acmeErr = acme.WrapError(acme.ErrorUnauthorizedType, err, msg)
+	}
+	acmeErr.Status = http.StatusForbidden // RFC8555 7.6 shows example with 403
+
+	switch {
+	case len(unauthorizedIdentifiers) > 0:
+		identifier := unauthorizedIdentifiers[0] // picking the first; compound may be an option too?
+		acmeErr.Detail = fmt.Sprintf("No authorization provided for name %s", identifier.Value)
+	case cert.Subject.String() != "":
+		acmeErr.Detail = fmt.Sprintf("No authorization provided for name %s", cert.Subject.CommonName)
+	default:
+		acmeErr.Detail = "No authorization provided"
+	}
+
+	return acmeErr
+}
+
+// logRevoke logs successful revocation of certificate
+func logRevoke(w http.ResponseWriter, ri *authority.RevokeOptions) {
+	if rl, ok := w.(logging.ResponseLogger); ok {
+		rl.WithFields(map[string]interface{}{
+			"serial":      ri.Serial,
+			"reasonCode":  ri.ReasonCode,
+			"reason":      ri.Reason,
+			"passiveOnly": ri.PassiveOnly,
+			"ACME":        ri.ACME,
+		})
+	}
+}
+
+// validateReasonCode validates the revocation reason
+func validateReasonCode(reasonCode *int) *acme.Error {
+	if reasonCode != nil && ((*reasonCode < ocsp.Unspecified || *reasonCode > ocsp.AACompromise) || *reasonCode == 7) {
+		return acme.NewError(acme.ErrorBadRevocationReasonType, "reasonCode out of bounds")
+	}
+	// NOTE: it's possible to add additional requirements to the reason code:
+	//		The server MAY disallow a subset of reasonCodes from being
+	//		used by the user. If a request contains a disallowed reasonCode,
+	//		then the server MUST reject it with the error type
+	//		"urn:ietf:params:acme:error:badRevocationReason"
+	// No additional checks have been implemented so far.
+	return nil
+}
+
+// revokeOptions determines the RevokeOptions for the Authority to use in revocation
+func revokeOptions(serial string, certToBeRevoked *x509.Certificate, reasonCode *int) *authority.RevokeOptions {
+	opts := &authority.RevokeOptions{
+		Serial: serial,
+		ACME:   true,
+		Crt:    certToBeRevoked,
+	}
+	if reasonCode != nil { // NOTE: when implementing CRL and/or OCSP, and reason code is missing, CRL entry extension should be omitted
+		opts.Reason = reason(*reasonCode)
+		opts.ReasonCode = *reasonCode
+	}
+	return opts
+}
+
+// reason transforms an integer reason code to a
+// textual description of the revocation reason.
+func reason(reasonCode int) string {
+	switch reasonCode {
+	case ocsp.Unspecified:
+		return "unspecified reason"
+	case ocsp.KeyCompromise:
+		return "key compromised"
+	case ocsp.CACompromise:
+		return "ca compromised"
+	case ocsp.AffiliationChanged:
+		return "affiliation changed"
+	case ocsp.Superseded:
+		return "superseded"
+	case ocsp.CessationOfOperation:
+		return "cessation of operation"
+	case ocsp.CertificateHold:
+		return "certificate hold"
+	case ocsp.RemoveFromCRL:
+		return "remove from crl"
+	case ocsp.PrivilegeWithdrawn:
+		return "privilege withdrawn"
+	case ocsp.AACompromise:
+		return "aa compromised"
+	default:
+		return "unspecified reason"
+	}
+}
+
+// shouldCheckAccountFrom indicates whether an account should be
+// retrieved from the context, so that it can be used for
+// additional checks. This should only be done when no JWK
+// can be extracted from the request, as that would indicate
+// that the revocation request was signed with a certificate
+// key pair (and not an account key pair). Looking up such
+// a JWK would result in no Account being found.
+func shouldCheckAccountFrom(jws *jose.JSONWebSignature) bool {
+	return !canExtractJWKFrom(jws)
+}

acme/challenge.go

@@ -26,8 +26,11 @@ import (
 type ChallengeType string
 
 const (
+	// HTTP01 is the http-01 ACME challenge type
 	HTTP01 ChallengeType = "http-01"
+	// DNS01 is the dns-01 ACME challenge type
 	DNS01 ChallengeType = "dns-01"
+	// TLSALPN01 is the tls-alpn-01 ACME challenge type
 	TLSALPN01 ChallengeType = "tls-alpn-01"
 )
 

acme/common.go

@@ -5,12 +5,15 @@ import (
 	"crypto/x509"
 	"time"
 
+	"github.com/smallstep/certificates/authority"
 	"github.com/smallstep/certificates/authority/provisioner"
 )
 
 // CertificateAuthority is the interface implemented by a CA authority.
 type CertificateAuthority interface {
 	Sign(cr *x509.CertificateRequest, opts provisioner.SignOptions, signOpts ...provisioner.SignOption) ([]*x509.Certificate, error)
+	IsRevoked(sn string) (bool, error)
+	Revoke(context.Context, *authority.RevokeOptions) error
 	LoadProvisionerByName(string) (provisioner.Interface, error)
 }
 
@@ -28,6 +31,7 @@ var clock Clock
 // only those methods required by the ACME api/authority.
 type Provisioner interface {
 	AuthorizeSign(ctx context.Context, token string) ([]provisioner.SignOption, error)
+	AuthorizeRevoke(ctx context.Context, token string) error
 	GetID() string
 	GetName() string
 	DefaultTLSCertDuration() time.Duration
@@ -41,6 +45,7 @@ type MockProvisioner struct {
 	MgetID                  func() string
 	MgetName                func() string
 	MauthorizeSign          func(ctx context.Context, ott string) ([]provisioner.SignOption, error)
+	MauthorizeRevoke        func(ctx context.Context, token string) error
 	MdefaultTLSCertDuration func() time.Duration
 	MgetOptions             func() *provisioner.Options
 }
@@ -61,6 +66,14 @@ func (m *MockProvisioner) AuthorizeSign(ctx context.Context, ott string) ([]prov
 	return m.Mret1.([]provisioner.SignOption), m.Merr
 }
 
+// AuthorizeRevoke mock
+func (m *MockProvisioner) AuthorizeRevoke(ctx context.Context, token string) error {
+	if m.MauthorizeRevoke != nil {
+		return m.MauthorizeRevoke(ctx, token)
+	}
+	return m.Merr
+}
+
 // DefaultTLSCertDuration mock
 func (m *MockProvisioner) DefaultTLSCertDuration() time.Duration {
 	if m.MdefaultTLSCertDuration != nil {

acme/db.go

@@ -25,9 +25,11 @@ type DB interface {
 	CreateAuthorization(ctx context.Context, az *Authorization) error
 	GetAuthorization(ctx context.Context, id string) (*Authorization, error)
 	UpdateAuthorization(ctx context.Context, az *Authorization) error
+	GetAuthorizationsByAccountID(ctx context.Context, accountID string) ([]*Authorization, error)
 
 	CreateCertificate(ctx context.Context, cert *Certificate) error
 	GetCertificate(ctx context.Context, id string) (*Certificate, error)
+	GetCertificateBySerial(ctx context.Context, serial string) (*Certificate, error)
 
 	CreateChallenge(ctx context.Context, ch *Challenge) error
 	GetChallenge(ctx context.Context, id, authzID string) (*Challenge, error)
@@ -53,9 +55,11 @@ type MockDB struct {
 	MockCreateAuthorization          func(ctx context.Context, az *Authorization) error
 	MockGetAuthorization             func(ctx context.Context, id string) (*Authorization, error)
 	MockUpdateAuthorization          func(ctx context.Context, az *Authorization) error
+	MockGetAuthorizationsByAccountID func(ctx context.Context, accountID string) ([]*Authorization, error)
 
 	MockCreateCertificate      func(ctx context.Context, cert *Certificate) error
 	MockGetCertificate         func(ctx context.Context, id string) (*Certificate, error)
+	MockGetCertificateBySerial func(ctx context.Context, serial string) (*Certificate, error)
 
 	MockCreateChallenge func(ctx context.Context, ch *Challenge) error
 	MockGetChallenge    func(ctx context.Context, id, authzID string) (*Challenge, error)
@@ -160,6 +164,16 @@ func (m *MockDB) UpdateAuthorization(ctx context.Context, az *Authorization) err
 	return m.MockError
 }
 
+// GetAuthorizationsByAccountID mock
+func (m *MockDB) GetAuthorizationsByAccountID(ctx context.Context, accountID string) ([]*Authorization, error) {
+	if m.MockGetAuthorizationsByAccountID != nil {
+		return m.MockGetAuthorizationsByAccountID(ctx, accountID)
+	} else if m.MockError != nil {
+		return nil, m.MockError
+	}
+	return nil, m.MockError
+}
+
 // CreateCertificate mock
 func (m *MockDB) CreateCertificate(ctx context.Context, cert *Certificate) error {
 	if m.MockCreateCertificate != nil {
@@ -180,6 +194,16 @@ func (m *MockDB) GetCertificate(ctx context.Context, id string) (*Certificate, e
 	return m.MockRet1.(*Certificate), m.MockError
 }
 
+// GetCertificateBySerial mock
+func (m *MockDB) GetCertificateBySerial(ctx context.Context, serial string) (*Certificate, error) {
+	if m.MockGetCertificateBySerial != nil {
+		return m.MockGetCertificateBySerial(ctx, serial)
+	} else if m.MockError != nil {
+		return nil, m.MockError
+	}
+	return m.MockRet1.(*Certificate), m.MockError
+}
+
 // CreateChallenge mock
 func (m *MockDB) CreateChallenge(ctx context.Context, ch *Challenge) error {
 	if m.MockCreateChallenge != nil {

acme/db/nosql/authz.go

@@ -116,3 +116,37 @@ func (db *DB) UpdateAuthorization(ctx context.Context, az *acme.Authorization) e
 	nu.Error = az.Error
 	return db.save(ctx, old.ID, nu, old, "authz", authzTable)
 }
+
+// GetAuthorizationsByAccountID retrieves and unmarshals ACME authz types from the database.
+func (db *DB) GetAuthorizationsByAccountID(ctx context.Context, accountID string) ([]*acme.Authorization, error) {
+	entries, err := db.db.List(authzTable)
+	if err != nil {
+		return nil, errors.Wrapf(err, "error listing authz")
+	}
+	authzs := []*acme.Authorization{}
+	for _, entry := range entries {
+		dbaz := new(dbAuthz)
+		if err = json.Unmarshal(entry.Value, dbaz); err != nil {
+			return nil, errors.Wrapf(err, "error unmarshaling dbAuthz key '%s' into dbAuthz struct", string(entry.Key))
+		}
+		// Filter out all dbAuthzs that don't belong to the accountID. This
+		// could be made more efficient with additional data structures mapping the
+		// Account ID to authorizations. Not trivial to do, though.
+		if dbaz.AccountID != accountID {
+			continue
+		}
+		authzs = append(authzs, &acme.Authorization{
+			ID:         dbaz.ID,
+			AccountID:  dbaz.AccountID,
+			Identifier: dbaz.Identifier,
+			Status:     dbaz.Status,
+			Challenges: nil, // challenges not required for current use case
+			Wildcard:   dbaz.Wildcard,
+			ExpiresAt:  dbaz.ExpiresAt,
+			Token:      dbaz.Token,
+			Error:      dbaz.Error,
+		})
+	}
+
+	return authzs, nil
+}

acme/db/nosql/authz_test.go

@@ -3,9 +3,11 @@ package nosql
 import (
 	"context"
 	"encoding/json"
+	"fmt"
 	"testing"
 	"time"
 
+	"github.com/google/go-cmp/cmp"
 	"github.com/pkg/errors"
 	"github.com/smallstep/assert"
 	"github.com/smallstep/certificates/acme"
@@ -614,3 +616,154 @@ func TestDB_UpdateAuthorization(t *testing.T) {
 		})
 	}
 }
+
+func TestDB_GetAuthorizationsByAccountID(t *testing.T) {
+	azID := "azID"
+	accountID := "accountID"
+	type test struct {
+		db      nosql.DB
+		err     error
+		acmeErr *acme.Error
+		authzs  []*acme.Authorization
+	}
+	var tests = map[string]func(t *testing.T) test{
+		"fail/db.List-error": func(t *testing.T) test {
+			return test{
+				db: &db.MockNoSQLDB{
+					MList: func(bucket []byte) ([]*nosqldb.Entry, error) {
+						assert.Equals(t, bucket, authzTable)
+						return nil, errors.New("force")
+					},
+				},
+				err: errors.New("error listing authz: force"),
+			}
+		},
+		"fail/unmarshal": func(t *testing.T) test {
+			b := []byte(`{malformed}`)
+			return test{
+				db: &db.MockNoSQLDB{
+					MList: func(bucket []byte) ([]*nosqldb.Entry, error) {
+						assert.Equals(t, bucket, authzTable)
+						return []*nosqldb.Entry{
+							{
+								Bucket: bucket,
+								Key:    []byte(azID),
+								Value:  b,
+							},
+						}, nil
+					},
+				},
+				authzs: nil,
+				err:    fmt.Errorf("error unmarshaling dbAuthz key '%s' into dbAuthz struct", azID),
+			}
+		},
+		"ok": func(t *testing.T) test {
+			now := clock.Now()
+			dbaz := &dbAuthz{
+				ID:        azID,
+				AccountID: accountID,
+				Identifier: acme.Identifier{
+					Type:  "dns",
+					Value: "test.ca.smallstep.com",
+				},
+				Status:       acme.StatusValid,
+				Token:        "token",
+				CreatedAt:    now,
+				ExpiresAt:    now.Add(5 * time.Minute),
+				ChallengeIDs: []string{"foo", "bar"},
+				Wildcard:     true,
+			}
+			b, err := json.Marshal(dbaz)
+			assert.FatalError(t, err)
+
+			return test{
+				db: &db.MockNoSQLDB{
+					MList: func(bucket []byte) ([]*nosqldb.Entry, error) {
+						assert.Equals(t, bucket, authzTable)
+						return []*nosqldb.Entry{
+							{
+								Bucket: bucket,
+								Key:    []byte(azID),
+								Value:  b,
+							},
+						}, nil
+					},
+				},
+				authzs: []*acme.Authorization{
+					{
+						ID:         dbaz.ID,
+						AccountID:  dbaz.AccountID,
+						Token:      dbaz.Token,
+						Identifier: dbaz.Identifier,
+						Status:     dbaz.Status,
+						Challenges: nil,
+						Wildcard:   dbaz.Wildcard,
+						ExpiresAt:  dbaz.ExpiresAt,
+						Error:      dbaz.Error,
+					},
+				},
+			}
+		},
+		"ok/skip-different-account": func(t *testing.T) test {
+			now := clock.Now()
+			dbaz := &dbAuthz{
+				ID:        azID,
+				AccountID: "differentAccountID",
+				Identifier: acme.Identifier{
+					Type:  "dns",
+					Value: "test.ca.smallstep.com",
+				},
+				Status:       acme.StatusValid,
+				Token:        "token",
+				CreatedAt:    now,
+				ExpiresAt:    now.Add(5 * time.Minute),
+				ChallengeIDs: []string{"foo", "bar"},
+				Wildcard:     true,
+			}
+			b, err := json.Marshal(dbaz)
+			assert.FatalError(t, err)
+
+			return test{
+				db: &db.MockNoSQLDB{
+					MList: func(bucket []byte) ([]*nosqldb.Entry, error) {
+						assert.Equals(t, bucket, authzTable)
+						return []*nosqldb.Entry{
+							{
+								Bucket: bucket,
+								Key:    []byte(azID),
+								Value:  b,
+							},
+						}, nil
+					},
+				},
+				authzs: []*acme.Authorization{},
+			}
+		},
+	}
+	for name, run := range tests {
+		tc := run(t)
+		t.Run(name, func(t *testing.T) {
+			d := DB{db: tc.db}
+			if azs, err := d.GetAuthorizationsByAccountID(context.Background(), accountID); err != nil {
+				switch k := err.(type) {
+				case *acme.Error:
+					if assert.NotNil(t, tc.acmeErr) {
+						assert.Equals(t, k.Type, tc.acmeErr.Type)
+						assert.Equals(t, k.Detail, tc.acmeErr.Detail)
+						assert.Equals(t, k.Status, tc.acmeErr.Status)
+						assert.Equals(t, k.Err.Error(), tc.acmeErr.Err.Error())
+						assert.Equals(t, k.Detail, tc.acmeErr.Detail)
+					}
+				default:
+					if assert.NotNil(t, tc.err) {
+						assert.HasPrefix(t, err.Error(), tc.err.Error())
+					}
+				}
+			} else if assert.Nil(t, tc.err) {
+				if !cmp.Equal(azs, tc.authzs) {
+					t.Errorf("db.GetAuthorizationsByAccountID() diff =\n%s", cmp.Diff(azs, tc.authzs))
+				}
+			}
+		})
+	}
+}

acme/db/nosql/certificate.go

@@ -21,6 +21,11 @@ type dbCert struct {
 	Intermediates []byte    `json:"intermediates"`
 }
 
+type dbSerial struct {
+	Serial        string `json:"serial"`
+	CertificateID string `json:"certificateID"`
+}
+
 // CreateCertificate creates and stores an ACME certificate type.
 func (db *DB) CreateCertificate(ctx context.Context, cert *acme.Certificate) error {
 	var err error
@@ -49,7 +54,17 @@ func (db *DB) CreateCertificate(ctx context.Context, cert *acme.Certificate) err
 		Intermediates: intermediates,
 		CreatedAt:     time.Now().UTC(),
 	}
-	return db.save(ctx, cert.ID, dbch, nil, "certificate", certTable)
+	err = db.save(ctx, cert.ID, dbch, nil, "certificate", certTable)
+	if err != nil {
+		return err
+	}
+
+	serial := cert.Leaf.SerialNumber.String()
+	dbSerial := &dbSerial{
+		Serial:        serial,
+		CertificateID: cert.ID,
+	}
+	return db.save(ctx, serial, dbSerial, nil, "serial", certBySerialTable)
 }
 
 // GetCertificate retrieves and unmarshals an ACME certificate type from the
@@ -80,6 +95,24 @@ func (db *DB) GetCertificate(ctx context.Context, id string) (*acme.Certificate,
 	}, nil
 }
 
+// GetCertificateBySerial retrieves and unmarshals an ACME certificate type from the
+// datastore based on a certificate serial number.
+func (db *DB) GetCertificateBySerial(ctx context.Context, serial string) (*acme.Certificate, error) {
+	b, err := db.db.Get(certBySerialTable, []byte(serial))
+	if nosql.IsErrNotFound(err) {
+		return nil, acme.NewError(acme.ErrorMalformedType, "certificate with serial %s not found", serial)
+	} else if err != nil {
+		return nil, errors.Wrapf(err, "error loading certificate ID for serial %s", serial)
+	}
+
+	dbSerial := new(dbSerial)
+	if err := json.Unmarshal(b, dbSerial); err != nil {
+		return nil, errors.Wrapf(err, "error unmarshaling certificate with serial %s", serial)
+	}
+
+	return db.GetCertificate(ctx, dbSerial.CertificateID)
+}
+
 func parseBundle(b []byte) ([]*x509.Certificate, error) {
 	var (
 		err    error

acme/db/nosql/certificate_test.go

@@ -1,10 +1,12 @@
 package nosql
 
 import (
+	"bytes"
 	"context"
 	"crypto/x509"
 	"encoding/json"
 	"encoding/pem"
+	"fmt"
 	"testing"
 	"time"
 
@@ -14,7 +16,6 @@ import (
 	"github.com/smallstep/certificates/db"
 	"github.com/smallstep/nosql"
 	nosqldb "github.com/smallstep/nosql/database"
-
 	"go.step.sm/crypto/pemutil"
 )
 
@@ -75,6 +76,10 @@ func TestDB_CreateCertificate(t *testing.T) {
 			return test{
 				db: &db.MockNoSQLDB{
 					MCmpAndSwap: func(bucket, key, old, nu []byte) ([]byte, bool, error) {
+						if !bytes.Equal(bucket, certTable) && !bytes.Equal(bucket, certBySerialTable) {
+							t.Fail()
+						}
+						if bytes.Equal(bucket, certTable) {
 							*idPtr = string(key)
 							assert.Equals(t, bucket, certTable)
 							assert.Equals(t, key, []byte(cert.ID))
@@ -87,6 +92,20 @@ func TestDB_CreateCertificate(t *testing.T) {
 							assert.Equals(t, dbc.AccountID, cert.AccountID)
 							assert.True(t, clock.Now().Add(-time.Minute).Before(dbc.CreatedAt))
 							assert.True(t, clock.Now().Add(time.Minute).After(dbc.CreatedAt))
+						}
+						if bytes.Equal(bucket, certBySerialTable) {
+							assert.Equals(t, bucket, certBySerialTable)
+							assert.Equals(t, key, []byte(cert.Leaf.SerialNumber.String()))
+							assert.Equals(t, old, nil)
+
+							dbs := new(dbSerial)
+							assert.FatalError(t, json.Unmarshal(nu, dbs))
+							assert.Equals(t, dbs.Serial, string(key))
+							assert.Equals(t, dbs.CertificateID, cert.ID)
+
+							*idPtr = cert.ID
+						}
+
 						return nil, true, nil
 					},
 				},
@@ -317,3 +336,135 @@ func Test_parseBundle(t *testing.T) {
 		})
 	}
 }
+
+func TestDB_GetCertificateBySerial(t *testing.T) {
+	leaf, err := pemutil.ReadCertificate("../../../authority/testdata/certs/foo.crt")
+	assert.FatalError(t, err)
+	inter, err := pemutil.ReadCertificate("../../../authority/testdata/certs/intermediate_ca.crt")
+	assert.FatalError(t, err)
+	root, err := pemutil.ReadCertificate("../../../authority/testdata/certs/root_ca.crt")
+	assert.FatalError(t, err)
+
+	certID := "certID"
+	serial := ""
+	type test struct {
+		db      nosql.DB
+		err     error
+		acmeErr *acme.Error
+	}
+	var tests = map[string]func(t *testing.T) test{
+		"fail/not-found": func(t *testing.T) test {
+			return test{
+				db: &db.MockNoSQLDB{
+					MGet: func(bucket, key []byte) ([]byte, error) {
+						if bytes.Equal(bucket, certBySerialTable) {
+							return nil, nosqldb.ErrNotFound
+						}
+						return nil, errors.New("wrong table")
+					},
+				},
+				acmeErr: acme.NewError(acme.ErrorMalformedType, "certificate with serial %s not found", serial),
+			}
+		},
+		"fail/db-error": func(t *testing.T) test {
+			return test{
+				db: &db.MockNoSQLDB{
+					MGet: func(bucket, key []byte) ([]byte, error) {
+						if bytes.Equal(bucket, certBySerialTable) {
+							return nil, errors.New("force")
+						}
+						return nil, errors.New("wrong table")
+					},
+				},
+				err: fmt.Errorf("error loading certificate ID for serial %s", serial),
+			}
+		},
+		"fail/unmarshal-dbSerial": func(t *testing.T) test {
+			return test{
+				db: &db.MockNoSQLDB{
+					MGet: func(bucket, key []byte) ([]byte, error) {
+						if bytes.Equal(bucket, certBySerialTable) {
+							return []byte(`{"serial":malformed!}`), nil
+						}
+						return nil, errors.New("wrong table")
+					},
+				},
+				err: fmt.Errorf("error unmarshaling certificate with serial %s", serial),
+			}
+		},
+		"ok": func(t *testing.T) test {
+			return test{
+				db: &db.MockNoSQLDB{
+					MGet: func(bucket, key []byte) ([]byte, error) {
+
+						if bytes.Equal(bucket, certBySerialTable) {
+							certSerial := dbSerial{
+								Serial:        serial,
+								CertificateID: certID,
+							}
+
+							b, err := json.Marshal(certSerial)
+							assert.FatalError(t, err)
+
+							return b, nil
+						}
+
+						if bytes.Equal(bucket, certTable) {
+							cert := dbCert{
+								ID:        certID,
+								AccountID: "accountID",
+								OrderID:   "orderID",
+								Leaf: pem.EncodeToMemory(&pem.Block{
+									Type:  "CERTIFICATE",
+									Bytes: leaf.Raw,
+								}),
+								Intermediates: append(pem.EncodeToMemory(&pem.Block{
+									Type:  "CERTIFICATE",
+									Bytes: inter.Raw,
+								}), pem.EncodeToMemory(&pem.Block{
+									Type:  "CERTIFICATE",
+									Bytes: root.Raw,
+								})...),
+								CreatedAt: clock.Now(),
+							}
+							b, err := json.Marshal(cert)
+							assert.FatalError(t, err)
+
+							return b, nil
+						}
+						return nil, errors.New("wrong table")
+					},
+				},
+			}
+		},
+	}
+	for name, prep := range tests {
+		tc := prep(t)
+		t.Run(name, func(t *testing.T) {
+			d := DB{db: tc.db}
+			cert, err := d.GetCertificateBySerial(context.Background(), serial)
+			if err != nil {
+				switch k := err.(type) {
+				case *acme.Error:
+					if assert.NotNil(t, tc.acmeErr) {
+						assert.Equals(t, k.Type, tc.acmeErr.Type)
+						assert.Equals(t, k.Detail, tc.acmeErr.Detail)
+						assert.Equals(t, k.Status, tc.acmeErr.Status)
+						assert.Equals(t, k.Err.Error(), tc.acmeErr.Err.Error())
+						assert.Equals(t, k.Detail, tc.acmeErr.Detail)
+					}
+				default:
+					if assert.NotNil(t, tc.err) {
+						assert.HasPrefix(t, err.Error(), tc.err.Error())
+					}
+				}
+			} else if assert.Nil(t, tc.err) {
+				assert.Equals(t, cert.ID, certID)
+				assert.Equals(t, cert.AccountID, "accountID")
+				assert.Equals(t, cert.OrderID, "orderID")
+				assert.Equals(t, cert.Leaf, leaf)
+				assert.Equals(t, cert.Intermediates, []*x509.Certificate{inter, root})
+			}
+		})
+	}
+}

acme/db/nosql/nosql.go

@@ -19,6 +19,7 @@ var (
 	orderTable             = []byte("acme_orders")
 	ordersByAccountIDTable = []byte("acme_account_orders_index")
 	certTable              = []byte("acme_certs")
+	certBySerialTable      = []byte("acme_serial_certs_index")
 )
 
 // DB is a struct that implements the AcmeDB interface.
@@ -29,7 +30,7 @@ type DB struct {
 // New configures and returns a new ACME DB backend implemented using a nosql DB.
 func New(db nosqlDB.DB) (*DB, error) {
 	tables := [][]byte{accountTable, accountByKeyIDTable, authzTable,
-		challengeTable, nonceTable, orderTable, ordersByAccountIDTable, certTable}
+		challengeTable, nonceTable, orderTable, ordersByAccountIDTable, certTable, certBySerialTable}
 	for _, b := range tables {
 		if err := db.CreateTable(b); err != nil {
 			return nil, errors.Wrapf(err, "error creating table %s",

acme/errors.go

@@ -147,7 +147,7 @@ var (
 		},
 		ErrorAlreadyRevokedType: {
 			typ:     officialACMEPrefix + ErrorAlreadyRevokedType.String(),
-			details: "Certificate already Revoked",
+			details: "Certificate already revoked",
 			status:  400,
 		},
 		ErrorBadCSRType: {

acme/order.go

@@ -17,7 +17,9 @@ import (
 type IdentifierType string
 
 const (
+	// IP is the ACME ip identifier type
 	IP IdentifierType = "ip"
+	// DNS is the ACME dns identifier type
 	DNS IdentifierType = "dns"
 )
 

acme/order_test.go

@@ -13,6 +13,7 @@ import (
 	"github.com/google/go-cmp/cmp"
 	"github.com/pkg/errors"
 	"github.com/smallstep/assert"
+	"github.com/smallstep/certificates/authority"
 	"github.com/smallstep/certificates/authority/provisioner"
 	"go.step.sm/crypto/x509util"
 )
@@ -287,6 +288,14 @@ func (m *mockSignAuth) LoadProvisionerByName(name string) (provisioner.Interface
 	return m.ret1.(provisioner.Interface), m.err
 }
 
+func (m *mockSignAuth) IsRevoked(sn string) (bool, error) {
+	return false, nil
+}
+
+func (m *mockSignAuth) Revoke(context.Context, *authority.RevokeOptions) error {
+	return nil
+}
+
 func TestOrder_Finalize(t *testing.T) {
 	type test struct {
 		o    *Order

api/api.go

@@ -348,7 +348,7 @@ func (h *caHandler) ProvisionerKey(w http.ResponseWriter, r *http.Request) {
 func (h *caHandler) Roots(w http.ResponseWriter, r *http.Request) {
 	roots, err := h.Authority.GetRoots()
 	if err != nil {
-		WriteError(w, errs.ForbiddenErr(err))
+		WriteError(w, errs.ForbiddenErr(err, "error getting roots"))
 		return
 	}
 
@@ -366,7 +366,7 @@ func (h *caHandler) Roots(w http.ResponseWriter, r *http.Request) {
 func (h *caHandler) Federation(w http.ResponseWriter, r *http.Request) {
 	federated, err := h.Authority.GetFederation()
 	if err != nil {
-		WriteError(w, errs.ForbiddenErr(err))
+		WriteError(w, errs.ForbiddenErr(err, "error getting federated roots"))
 		return
 	}
 

api/revoke.go

@@ -96,7 +96,7 @@ func (h *caHandler) Revoke(w http.ResponseWriter, r *http.Request) {
 	}
 
 	if err := h.Authority.Revoke(ctx, opts); err != nil {
-		WriteError(w, errs.ForbiddenErr(err))
+		WriteError(w, errs.ForbiddenErr(err, "error revoking certificate"))
 		return
 	}
 

api/sign.go

@@ -74,7 +74,7 @@ func (h *caHandler) Sign(w http.ResponseWriter, r *http.Request) {
 
 	certChain, err := h.Authority.Sign(body.CsrPEM.CertificateRequest, opts, signOpts...)
 	if err != nil {
-		WriteError(w, errs.ForbiddenErr(err))
+		WriteError(w, errs.ForbiddenErr(err, "error signing certificate"))
 		return
 	}
 	certChainPEM := certChainToPEM(certChain)

api/ssh.go

@@ -293,7 +293,7 @@ func (h *caHandler) SSHSign(w http.ResponseWriter, r *http.Request) {
 
 	cert, err := h.Authority.SignSSH(ctx, publicKey, opts, signOpts...)
 	if err != nil {
-		WriteError(w, errs.ForbiddenErr(err))
+		WriteError(w, errs.ForbiddenErr(err, "error signing ssh certificate"))
 		return
 	}
 
@@ -301,7 +301,7 @@ func (h *caHandler) SSHSign(w http.ResponseWriter, r *http.Request) {
 	if addUserPublicKey != nil && authority.IsValidForAddUser(cert) == nil {
 		addUserCert, err := h.Authority.SignSSHAddUser(ctx, addUserPublicKey, cert)
 		if err != nil {
-			WriteError(w, errs.ForbiddenErr(err))
+			WriteError(w, errs.ForbiddenErr(err, "error signing ssh certificate"))
 			return
 		}
 		addUserCertificate = &SSHCertificate{addUserCert}
@@ -326,7 +326,7 @@ func (h *caHandler) SSHSign(w http.ResponseWriter, r *http.Request) {
 
 		certChain, err := h.Authority.Sign(cr, provisioner.SignOptions{}, signOpts...)
 		if err != nil {
-			WriteError(w, errs.ForbiddenErr(err))
+			WriteError(w, errs.ForbiddenErr(err, "error signing identity certificate"))
 			return
 		}
 		identityCertificate = certChainToPEM(certChain)

api/sshRekey.go

@@ -68,7 +68,7 @@ func (h *caHandler) SSHRekey(w http.ResponseWriter, r *http.Request) {
 
 	newCert, err := h.Authority.RekeySSH(ctx, oldCert, publicKey, signOpts...)
 	if err != nil {
-		WriteError(w, errs.ForbiddenErr(err))
+		WriteError(w, errs.ForbiddenErr(err, "error rekeying ssh certificate"))
 		return
 	}
 
@@ -78,7 +78,7 @@ func (h *caHandler) SSHRekey(w http.ResponseWriter, r *http.Request) {
 
 	identity, err := h.renewIdentityCertificate(r, notBefore, notAfter)
 	if err != nil {
-		WriteError(w, errs.ForbiddenErr(err))
+		WriteError(w, errs.ForbiddenErr(err, "error renewing identity certificate"))
 		return
 	}
 

api/sshRenew.go

@@ -60,7 +60,7 @@ func (h *caHandler) SSHRenew(w http.ResponseWriter, r *http.Request) {
 
 	newCert, err := h.Authority.RenewSSH(ctx, oldCert)
 	if err != nil {
-		WriteError(w, errs.ForbiddenErr(err))
+		WriteError(w, errs.ForbiddenErr(err, "error renewing ssh certificate"))
 		return
 	}
 
@@ -70,7 +70,7 @@ func (h *caHandler) SSHRenew(w http.ResponseWriter, r *http.Request) {
 
 	identity, err := h.renewIdentityCertificate(r, notBefore, notAfter)
 	if err != nil {
-		WriteError(w, errs.ForbiddenErr(err))
+		WriteError(w, errs.ForbiddenErr(err, "error renewing identity certificate"))
 		return
 	}
 

api/sshRevoke.go

@@ -75,7 +75,7 @@ func (h *caHandler) SSHRevoke(w http.ResponseWriter, r *http.Request) {
 	opts.OTT = body.OTT
 
 	if err := h.Authority.Revoke(ctx, opts); err != nil {
-		WriteError(w, errs.ForbiddenErr(err))
+		WriteError(w, errs.ForbiddenErr(err, "error revoking ssh certificate"))
 		return
 	}
 

authority/authority.go

@@ -588,6 +588,19 @@ func (a *Authority) CloseForReload() {
 	}
 }
 
+// IsRevoked returns whether or not a certificate has been
+// revoked before.
+func (a *Authority) IsRevoked(sn string) (bool, error) {
+	// Check the passive revocation table.
+	if lca, ok := a.adminDB.(interface {
+		IsRevoked(string) (bool, error)
+	}); ok {
+		return lca.IsRevoked(sn)
+	}
+
+	return a.db.IsRevoked(sn)
+}
+
 // requiresDecrypter returns whether the Authority
 // requires a KMS that provides a crypto.Decrypter
 // Currently this is only required when SCEP is

authority/authorize.go

@@ -274,19 +274,9 @@ func (a *Authority) authorizeRevoke(ctx context.Context, token string) error {
 //
 // TODO(mariano): should we authorize by default?
 func (a *Authority) authorizeRenew(cert *x509.Certificate) error {
-	var err error
-	var isRevoked bool
-	var opts = []interface{}{errs.WithKeyVal("serialNumber", cert.SerialNumber.String())}
-
-	// Check the passive revocation table.
 	serial := cert.SerialNumber.String()
-	if lca, ok := a.adminDB.(interface {
+	var opts = []interface{}{errs.WithKeyVal("serialNumber", serial)}
-		IsRevoked(string) (bool, error)
+	isRevoked, err := a.IsRevoked(serial)
-	}); ok {
-		isRevoked, err = lca.IsRevoked(serial)
-	} else {
-		isRevoked, err = a.db.IsRevoked(serial)
-	}
 	if err != nil {
 		return errs.Wrap(http.StatusInternalServerError, err, "authority.authorizeRenew", opts...)
 	}

authority/provisioner/acme.go

@@ -99,6 +99,15 @@ func (p *ACME) AuthorizeSign(ctx context.Context, token string) ([]SignOption, e
 	}, nil
 }
 
+// AuthorizeRevoke is called just before the certificate is to be revoked by
+// the CA. It can be used to authorize revocation of a certificate. It
+// currently is a no-op.
+// TODO(hs): add configuration option that toggles revocation? Or change function signature to make it more useful?
+// Or move certain logic out of the Revoke API to here? Would likely involve some more stuff in the ctx.
+func (p *ACME) AuthorizeRevoke(ctx context.Context, token string) error {
+	return nil
+}
+
 // AuthorizeRenew returns an error if the renewal is disabled.
 // NOTE: This method does not actually validate the certificate or check it's
 // revocation status. Just confirms that the provisioner that created the

authority/provisioner/provisioner_test.go

@@ -184,7 +184,6 @@ func TestUnimplementedMethods(t *testing.T) {
 		{"x5c/sshRenew", &X5C{}, SSHRenewMethod},
 		{"x5c/sshRekey", &X5C{}, SSHRekeyMethod},
 		{"x5c/sshRevoke", &X5C{}, SSHRekeyMethod},
-		{"acme/revoke", &ACME{}, RevokeMethod},
 		{"acme/sshSign", &ACME{}, SSHSignMethod},
 		{"acme/sshRekey", &ACME{}, SSHRekeyMethod},
 		{"acme/sshRenew", &ACME{}, SSHRenewMethod},

authority/provisioner/sign_options.go

@@ -9,12 +9,14 @@ import (
 	"encoding/asn1"
 	"encoding/json"
 	"net"
+	"net/http"
 	"net/url"
 	"reflect"
 	"time"
 
 	"github.com/pkg/errors"
 	"github.com/smallstep/certificates/errs"
+	"go.step.sm/crypto/keyutil"
 	"go.step.sm/crypto/x509util"
 )
 
@@ -83,19 +85,19 @@ type emailOnlyIdentity string
 func (e emailOnlyIdentity) Valid(req *x509.CertificateRequest) error {
 	switch {
 	case len(req.DNSNames) > 0:
-		return errors.New("certificate request cannot contain DNS names")
+		return errs.Forbidden("certificate request cannot contain DNS names")
 	case len(req.IPAddresses) > 0:
-		return errors.New("certificate request cannot contain IP addresses")
+		return errs.Forbidden("certificate request cannot contain IP addresses")
 	case len(req.URIs) > 0:
-		return errors.New("certificate request cannot contain URIs")
+		return errs.Forbidden("certificate request cannot contain URIs")
 	case len(req.EmailAddresses) == 0:
-		return errors.New("certificate request does not contain any email address")
+		return errs.Forbidden("certificate request does not contain any email address")
 	case len(req.EmailAddresses) > 1:
-		return errors.New("certificate request contains too many email addresses")
+		return errs.Forbidden("certificate request contains too many email addresses")
 	case req.EmailAddresses[0] == "":
-		return errors.New("certificate request cannot contain an empty email address")
+		return errs.Forbidden("certificate request cannot contain an empty email address")
 	case req.EmailAddresses[0] != string(e):
-		return errors.Errorf("certificate request does not contain the valid email address, got %s, want %s", req.EmailAddresses[0], e)
+		return errs.Forbidden("certificate request does not contain the valid email address - got %s, want %s", req.EmailAddresses[0], e)
 	default:
 		return nil
 	}
@@ -108,12 +110,13 @@ type defaultPublicKeyValidator struct{}
 func (v defaultPublicKeyValidator) Valid(req *x509.CertificateRequest) error {
 	switch k := req.PublicKey.(type) {
 	case *rsa.PublicKey:
-		if k.Size() < 256 {
+		if k.Size() < keyutil.MinRSAKeyBytes {
-			return errors.New("rsa key in CSR must be at least 2048 bits (256 bytes)")
+			return errs.Forbidden("certificate request RSA key must be at least %d bits (%d bytes)",
+				8*keyutil.MinRSAKeyBytes, keyutil.MinRSAKeyBytes)
 		}
 	case *ecdsa.PublicKey, ed25519.PublicKey:
 	default:
-		return errors.Errorf("unrecognized public key of type '%T' in CSR", k)
+		return errs.BadRequest("certificate request key of type '%T' is not supported", k)
 	}
 	return nil
 }
@@ -139,11 +142,12 @@ func (v publicKeyMinimumLengthValidator) Valid(req *x509.CertificateRequest) err
 	case *rsa.PublicKey:
 		minimumLengthInBytes := v.length / 8
 		if k.Size() < minimumLengthInBytes {
-			return errors.Errorf("rsa key in CSR must be at least %d bits (%d bytes)", v.length, minimumLengthInBytes)
+			return errs.Forbidden("certificate request RSA key must be at least %d bits (%d bytes)",
+				v.length, minimumLengthInBytes)
 		}
 	case *ecdsa.PublicKey, ed25519.PublicKey:
 	default:
-		return errors.Errorf("unrecognized public key of type '%T' in CSR", k)
+		return errs.BadRequest("certificate request key of type '%T' is not supported", k)
 	}
 	return nil
 }
@@ -158,7 +162,7 @@ func (v commonNameValidator) Valid(req *x509.CertificateRequest) error {
 		return nil
 	}
 	if req.Subject.CommonName != string(v) {
-		return errors.Errorf("certificate request does not contain the valid common name; requested common name = %s, token subject = %s", req.Subject.CommonName, v)
+		return errs.Forbidden("certificate request does not contain the valid common name - got %s, want %s", req.Subject.CommonName, v)
 	}
 	return nil
 }
@@ -176,7 +180,7 @@ func (v commonNameSliceValidator) Valid(req *x509.CertificateRequest) error {
 			return nil
 		}
 	}
-	return errors.Errorf("certificate request does not contain the valid common name, got %s, want %s", req.Subject.CommonName, v)
+	return errs.Forbidden("certificate request does not contain the valid common name - got %s, want %s", req.Subject.CommonName, v)
 }
 
 // dnsNamesValidator validates the DNS names SAN of a certificate request.
@@ -197,7 +201,7 @@ func (v dnsNamesValidator) Valid(req *x509.CertificateRequest) error {
 		got[s] = true
 	}
 	if !reflect.DeepEqual(want, got) {
-		return errors.Errorf("certificate request does not contain the valid DNS names - got %v, want %v", req.DNSNames, v)
+		return errs.Forbidden("certificate request does not contain the valid DNS names - got %v, want %v", req.DNSNames, v)
 	}
 	return nil
 }
@@ -220,7 +224,7 @@ func (v ipAddressesValidator) Valid(req *x509.CertificateRequest) error {
 		got[ip.String()] = true
 	}
 	if !reflect.DeepEqual(want, got) {
-		return errors.Errorf("IP Addresses claim failed - got %v, want %v", req.IPAddresses, v)
+		return errs.Forbidden("certificate request does not contain the valid IP addresses - got %v, want %v", req.IPAddresses, v)
 	}
 	return nil
 }
@@ -243,7 +247,7 @@ func (v emailAddressesValidator) Valid(req *x509.CertificateRequest) error {
 		got[s] = true
 	}
 	if !reflect.DeepEqual(want, got) {
-		return errors.Errorf("certificate request does not contain the valid Email Addresses - got %v, want %v", req.EmailAddresses, v)
+		return errs.Forbidden("certificate request does not contain the valid email addresses - got %v, want %v", req.EmailAddresses, v)
 	}
 	return nil
 }
@@ -266,7 +270,7 @@ func (v urisValidator) Valid(req *x509.CertificateRequest) error {
 		got[u.String()] = true
 	}
 	if !reflect.DeepEqual(want, got) {
-		return errors.Errorf("URIs claim failed - got %v, want %v", req.URIs, v)
+		return errs.Forbidden("certificate request does not contain the valid URIs - got %v, want %v", req.URIs, v)
 	}
 	return nil
 }
@@ -334,15 +338,15 @@ func (v profileLimitDuration) Modify(cert *x509.Certificate, so SignOptions) err
 		backdate = -1 * so.Backdate
 	}
 	if notBefore.Before(v.notBefore) {
-		return errors.Errorf("requested certificate notBefore (%s) is before "+
+		return errs.Forbidden(
-			"the active validity window of the provisioning credential (%s)",
+			"requested certificate notBefore (%s) is before the active validity window of the provisioning credential (%s)",
 			notBefore, v.notBefore)
 	}
 
 	notAfter := so.NotAfter.RelativeTime(notBefore)
 	if notAfter.After(v.notAfter) {
-		return errors.Errorf("requested certificate notAfter (%s) is after "+
+		return errs.Forbidden(
-			"the expiration of the provisioning credential (%s)",
+			"requested certificate notAfter (%s) is after the expiration of the provisioning credential (%s)",
 			notAfter, v.notAfter)
 	}
 	if notAfter.IsZero() {
@@ -388,14 +392,14 @@ func (v *validityValidator) Valid(cert *x509.Certificate, o SignOptions) error {
 		return errs.BadRequest("notAfter cannot be before notBefore; na=%v, nb=%v", na, nb)
 	}
 	if d < v.min {
-		return errs.BadRequest("requested duration of %v is less than the authorized minimum certificate duration of %v", d, v.min)
+		return errs.Forbidden("requested duration of %v is less than the authorized minimum certificate duration of %v", d, v.min)
 	}
 	// NOTE: this check is not "technically correct". We're allowing the max
 	// duration of a cert to be "max + backdate" and not all certificates will
 	// be backdated (e.g. if a user passes the NotBefore value then we do not
 	// apply a backdate). This is good enough.
 	if d > v.max+o.Backdate {
-		return errs.BadRequest("requested duration of %v is more than the authorized maximum certificate duration of %v", d, v.max+o.Backdate)
+		return errs.Forbidden("requested duration of %v is more than the authorized maximum certificate duration of %v", d, v.max+o.Backdate)
 	}
 	return nil
 }
@@ -422,16 +426,15 @@ func newForceCNOption(forceCN bool) *forceCNOption {
 
 func (o *forceCNOption) Modify(cert *x509.Certificate, _ SignOptions) error {
 	if !o.ForceCN {
-		// Forcing CN is disabled, do nothing to certificate
 		return nil
 	}
 
+	// Force the common name to be the first DNS if not provided.
 	if cert.Subject.CommonName == "" {
-		if len(cert.DNSNames) > 0 {
+		if len(cert.DNSNames) == 0 {
-			cert.Subject.CommonName = cert.DNSNames[0]
+			return errs.BadRequest("cannot force common name, DNS names is empty")
-		} else {
-			return errors.New("Cannot force CN, DNSNames is empty")
 		}
+		cert.Subject.CommonName = cert.DNSNames[0]
 	}
 
 	return nil
@@ -456,7 +459,7 @@ func newProvisionerExtensionOption(typ Type, name, credentialID string, keyValue
 func (o *provisionerExtensionOption) Modify(cert *x509.Certificate, _ SignOptions) error {
 	ext, err := createProvisionerExtension(o.Type, o.Name, o.CredentialID, o.KeyValuePairs...)
 	if err != nil {
-		return err
+		return errs.NewError(http.StatusInternalServerError, err, "error creating certificate")
 	}
 	// Prepend the provisioner extension. In the auth.Sign code we will
 	// force the resulting certificate to only have one extension, the
@@ -477,7 +480,7 @@ func createProvisionerExtension(typ int, name, credentialID string, keyValuePair
 		KeyValuePairs: keyValuePairs,
 	})
 	if err != nil {
-		return pkix.Extension{}, errors.Wrapf(err, "error marshaling provisioner extension")
+		return pkix.Extension{}, errors.Wrap(err, "error marshaling provisioner extension")
 	}
 	return pkix.Extension{
 		Id:       stepOIDProvisioner,

authority/provisioner/sign_options_test.go

@@ -77,12 +77,12 @@ func Test_defaultPublicKeyValidator_Valid(t *testing.T) {
 		{
 			"fail/unrecognized-key-type",
 			&x509.CertificateRequest{PublicKey: "foo"},
-			errors.New("unrecognized public key of type 'string' in CSR"),
+			errors.New("certificate request key of type 'string' is not supported"),
 		},
 		{
 			"fail/rsa/too-short",
 			shortRSA,
-			errors.New("rsa key in CSR must be at least 2048 bits (256 bytes)"),
+			errors.New("certificate request RSA key must be at least 2048 bits (256 bytes)"),
 		},
 		{
 			"ok/rsa",
@@ -303,14 +303,14 @@ func Test_defaultSANsValidator_Valid(t *testing.T) {
 			return test{
 				csr:          &x509.CertificateRequest{EmailAddresses: []string{"max@fx.com", "mariano@fx.com"}},
 				expectedSANs: []string{"dcow@fx.com"},
-				err:          errors.New("certificate request does not contain the valid Email Addresses"),
+				err:          errors.New("certificate request does not contain the valid email addresses"),
 			}
 		},
 		"fail/ipAddressesValidator": func() test {
 			return test{
 				csr:          &x509.CertificateRequest{IPAddresses: []net.IP{net.ParseIP("1.1.1.1"), net.ParseIP("127.0.0.1")}},
 				expectedSANs: []string{"127.0.0.1"},
-				err:          errors.New("IP Addresses claim failed"),
+				err:          errors.New("certificate request does not contain the valid IP addresses"),
 			}
 		},
 		"fail/urisValidator": func() test {
@@ -321,7 +321,7 @@ func Test_defaultSANsValidator_Valid(t *testing.T) {
 			return test{
 				csr:          &x509.CertificateRequest{URIs: []*url.URL{u1, u2}},
 				expectedSANs: []string{"urn:uuid:ddfe62ba-7e99-4bc1-83b3-8f57fe3e9959"},
-				err:          errors.New("URIs claim failed"),
+				err:          errors.New("certificate request does not contain the valid URIs"),
 			}
 		},
 		"ok": func() test {
@@ -512,7 +512,7 @@ func Test_forceCN_Option(t *testing.T) {
 					Subject:  pkix.Name{},
 					DNSNames: []string{},
 				},
-				err: errors.New("Cannot force CN, DNSNames is empty"),
+				err: errors.New("cannot force common name, DNS names is empty"),
 			}
 		},
 	}

authority/provisioner/sign_ssh_options.go

@@ -56,7 +56,12 @@ type SignSSHOptions struct {
 // Validate validates the given SignSSHOptions.
 func (o SignSSHOptions) Validate() error {
 	if o.CertType != "" && o.CertType != SSHUserCert && o.CertType != SSHHostCert {
-		return errs.BadRequest("unknown certificate type '%s'", o.CertType)
+		return errs.BadRequest("certType '%s' is not valid", o.CertType)
+	}
+	for _, p := range o.Principals {
+		if p == "" {
+			return errs.BadRequest("principals cannot contain empty values")
+		}
 	}
 	return nil
 }
@@ -75,7 +80,7 @@ func (o SignSSHOptions) Modify(cert *ssh.Certificate, _ SignSSHOptions) error {
 	case SSHHostCert:
 		cert.CertType = ssh.HostCert
 	default:
-		return errors.Errorf("ssh certificate has an unknown type - %s", o.CertType)
+		return errs.BadRequest("ssh certificate has an unknown type '%s'", o.CertType)
 	}
 
 	cert.KeyId = o.KeyID
@@ -95,7 +100,7 @@ func (o SignSSHOptions) ModifyValidity(cert *ssh.Certificate) error {
 		cert.ValidBefore = uint64(o.ValidBefore.RelativeTime(t).Unix())
 	}
 	if cert.ValidAfter > 0 && cert.ValidBefore > 0 && cert.ValidAfter > cert.ValidBefore {
-		return errors.New("ssh certificate valid after cannot be greater than valid before")
+		return errs.BadRequest("ssh certificate validAfter cannot be greater than validBefore")
 	}
 	return nil
 }
@@ -104,16 +109,16 @@ func (o SignSSHOptions) ModifyValidity(cert *ssh.Certificate) error {
 // ignores zero values.
 func (o SignSSHOptions) match(got SignSSHOptions) error {
 	if o.CertType != "" && got.CertType != "" && o.CertType != got.CertType {
-		return errors.Errorf("ssh certificate type does not match - got %v, want %v", got.CertType, o.CertType)
+		return errs.Forbidden("ssh certificate type does not match - got %v, want %v", got.CertType, o.CertType)
 	}
 	if len(o.Principals) > 0 && len(got.Principals) > 0 && !containsAllMembers(o.Principals, got.Principals) {
-		return errors.Errorf("ssh certificate principals does not match - got %v, want %v", got.Principals, o.Principals)
+		return errs.Forbidden("ssh certificate principals does not match - got %v, want %v", got.Principals, o.Principals)
 	}
 	if !o.ValidAfter.IsZero() && !got.ValidAfter.IsZero() && !o.ValidAfter.Equal(&got.ValidAfter) {
-		return errors.Errorf("ssh certificate valid after does not match - got %v, want %v", got.ValidAfter, o.ValidAfter)
+		return errs.Forbidden("ssh certificate validAfter does not match - got %v, want %v", got.ValidAfter, o.ValidAfter)
 	}
 	if !o.ValidBefore.IsZero() && !got.ValidBefore.IsZero() && !o.ValidBefore.Equal(&got.ValidBefore) {
-		return errors.Errorf("ssh certificate valid before does not match - got %v, want %v", got.ValidBefore, o.ValidBefore)
+		return errs.Forbidden("ssh certificate validBefore does not match - got %v, want %v", got.ValidBefore, o.ValidBefore)
 	}
 	return nil
 }
@@ -206,7 +211,7 @@ func (m *sshDefaultExtensionModifier) Modify(cert *ssh.Certificate, _ SignSSHOpt
 		cert.Extensions["permit-user-rc"] = ""
 		return nil
 	default:
-		return errors.New("ssh certificate type has not been set or is invalid")
+		return errs.BadRequest("ssh certificate has an unknown type '%d'", cert.CertType)
 	}
 }
 
@@ -272,7 +277,7 @@ func (m *sshLimitDuration) Modify(cert *ssh.Certificate, o SignSSHOptions) error
 
 	certValidAfter := time.Unix(int64(cert.ValidAfter), 0)
 	if certValidAfter.After(m.NotAfter) {
-		return errors.Errorf("provisioning credential expiration (%s) is before requested certificate validAfter (%s)",
+		return errs.Forbidden("provisioning credential expiration (%s) is before requested certificate validAfter (%s)",
 			m.NotAfter, certValidAfter)
 	}
 
@@ -285,7 +290,7 @@ func (m *sshLimitDuration) Modify(cert *ssh.Certificate, o SignSSHOptions) error
 	} else {
 		certValidBefore := time.Unix(int64(cert.ValidBefore), 0)
 		if m.NotAfter.Before(certValidBefore) {
-			return errors.Errorf("provisioning credential expiration (%s) is before requested certificate validBefore (%s)",
+			return errs.Forbidden("provisioning credential expiration (%s) is before requested certificate validBefore (%s)",
 				m.NotAfter, certValidBefore)
 		}
 	}
@@ -319,11 +324,11 @@ type sshCertOptionsRequireValidator struct {
 func (v *sshCertOptionsRequireValidator) Valid(got SignSSHOptions) error {
 	switch {
 	case v.CertType && got.CertType == "":
-		return errors.New("ssh certificate certType cannot be empty")
+		return errs.BadRequest("ssh certificate certType cannot be empty")
 	case v.KeyID && got.KeyID == "":
-		return errors.New("ssh certificate keyID cannot be empty")
+		return errs.BadRequest("ssh certificate keyID cannot be empty")
 	case v.Principals && len(got.Principals) == 0:
-		return errors.New("ssh certificate principals cannot be empty")
+		return errs.BadRequest("ssh certificate principals cannot be empty")
 	default:
 		return nil
 	}
@@ -354,7 +359,7 @@ func (v *sshCertValidityValidator) Valid(cert *ssh.Certificate, opts SignSSHOpti
 	case 0:
 		return errs.BadRequest("ssh certificate type has not been set")
 	default:
-		return errs.BadRequest("unknown ssh certificate type %d", cert.CertType)
+		return errs.BadRequest("ssh certificate has an unknown type '%d'", cert.CertType)
 	}
 
 	// To not take into account the backdate, time.Now() will be used to
@@ -363,9 +368,9 @@ func (v *sshCertValidityValidator) Valid(cert *ssh.Certificate, opts SignSSHOpti
 
 	switch {
 	case dur < min:
-		return errs.BadRequest("requested duration of %s is less than minimum accepted duration for selected provisioner of %s", dur, min)
+		return errs.Forbidden("requested duration of %s is less than minimum accepted duration for selected provisioner of %s", dur, min)
 	case dur > max+opts.Backdate:
-		return errs.BadRequest("requested duration of %s is greater than maximum accepted duration for selected provisioner of %s", dur, max+opts.Backdate)
+		return errs.Forbidden("requested duration of %s is greater than maximum accepted duration for selected provisioner of %s", dur, max+opts.Backdate)
 	default:
 		return nil
 	}
@@ -381,25 +386,25 @@ type sshCertDefaultValidator struct{}
 func (v *sshCertDefaultValidator) Valid(cert *ssh.Certificate, o SignSSHOptions) error {
 	switch {
 	case len(cert.Nonce) == 0:
-		return errors.New("ssh certificate nonce cannot be empty")
+		return errs.Forbidden("ssh certificate nonce cannot be empty")
 	case cert.Key == nil:
-		return errors.New("ssh certificate key cannot be nil")
+		return errs.Forbidden("ssh certificate key cannot be nil")
 	case cert.Serial == 0:
-		return errors.New("ssh certificate serial cannot be 0")
+		return errs.Forbidden("ssh certificate serial cannot be 0")
 	case cert.CertType != ssh.UserCert && cert.CertType != ssh.HostCert:
-		return errors.Errorf("ssh certificate has an unknown type: %d", cert.CertType)
+		return errs.Forbidden("ssh certificate has an unknown type '%d'", cert.CertType)
 	case cert.KeyId == "":
-		return errors.New("ssh certificate key id cannot be empty")
+		return errs.Forbidden("ssh certificate key id cannot be empty")
 	case cert.ValidAfter == 0:
-		return errors.New("ssh certificate validAfter cannot be 0")
+		return errs.Forbidden("ssh certificate validAfter cannot be 0")
 	case cert.ValidBefore < uint64(now().Unix()):
-		return errors.New("ssh certificate validBefore cannot be in the past")
+		return errs.Forbidden("ssh certificate validBefore cannot be in the past")
 	case cert.ValidBefore < cert.ValidAfter:
-		return errors.New("ssh certificate validBefore cannot be before validAfter")
+		return errs.Forbidden("ssh certificate validBefore cannot be before validAfter")
 	case cert.SignatureKey == nil:
-		return errors.New("ssh certificate signature key cannot be nil")
+		return errs.Forbidden("ssh certificate signature key cannot be nil")
 	case cert.Signature == nil:
-		return errors.New("ssh certificate signature cannot be nil")
+		return errs.Forbidden("ssh certificate signature cannot be nil")
 	default:
 		return nil
 	}
@@ -409,27 +414,31 @@ func (v *sshCertDefaultValidator) Valid(cert *ssh.Certificate, o SignSSHOptions)
 type sshDefaultPublicKeyValidator struct{}
 
 // Valid checks that certificate request common name matches the one configured.
+//
+// TODO: this is the only validator that checks the key type. We should execute
+// this before the signing. We should add a new validations interface or extend
+// SSHCertOptionsValidator with the key.
 func (v sshDefaultPublicKeyValidator) Valid(cert *ssh.Certificate, o SignSSHOptions) error {
 	if cert.Key == nil {
-		return errors.New("ssh certificate key cannot be nil")
+		return errs.BadRequest("ssh certificate key cannot be nil")
 	}
 	switch cert.Key.Type() {
 	case ssh.KeyAlgoRSA:
 		_, in, ok := sshParseString(cert.Key.Marshal())
 		if !ok {
-			return errors.New("ssh certificate key is invalid")
+			return errs.BadRequest("ssh certificate key is invalid")
 		}
 		key, err := sshParseRSAPublicKey(in)
 		if err != nil {
-			return err
+			return errs.BadRequestErr(err, "error parsing public key")
 		}
 		if key.Size() < keyutil.MinRSAKeyBytes {
-			return errors.Errorf("ssh certificate key must be at least %d bits (%d bytes)",
+			return errs.Forbidden("ssh certificate key must be at least %d bits (%d bytes)",
 				8*keyutil.MinRSAKeyBytes, keyutil.MinRSAKeyBytes)
 		}
 		return nil
 	case ssh.KeyAlgoDSA:
-		return errors.New("ssh certificate key algorithm (DSA) is not supported")
+		return errs.BadRequest("ssh certificate key algorithm (DSA) is not supported")
 	default:
 		return nil
 	}

authority/provisioner/sign_ssh_options_test.go

@@ -49,14 +49,14 @@ func TestSSHOptions_Modify(t *testing.T) {
 			return test{
 				so:   SignSSHOptions{CertType: "foo"},
 				cert: new(ssh.Certificate),
-				err:  errors.Errorf("ssh certificate has an unknown type - foo"),
+				err:  errors.Errorf("ssh certificate has an unknown type 'foo'"),
 			}
 		},
 		"fail/validAfter-greater-validBefore": func() test {
 			return test{
 				so:   SignSSHOptions{CertType: "user"},
 				cert: &ssh.Certificate{ValidAfter: uint64(15), ValidBefore: uint64(10)},
-				err:  errors.Errorf("ssh certificate valid after cannot be greater than valid before"),
+				err:  errors.Errorf("ssh certificate validAfter cannot be greater than validBefore"),
 			}
 		},
 		"ok/user-cert": func() test {
@@ -136,14 +136,14 @@ func TestSSHOptions_Match(t *testing.T) {
 			return test{
 				so:  SignSSHOptions{ValidAfter: NewTimeDuration(time.Now().Add(1 * time.Minute))},
 				cmp: SignSSHOptions{ValidAfter: NewTimeDuration(time.Now().Add(5 * time.Minute))},
-				err: errors.Errorf("ssh certificate valid after does not match"),
+				err: errors.Errorf("ssh certificate validAfter does not match"),
 			}
 		},
 		"fail/validBefore": func() test {
 			return test{
 				so:  SignSSHOptions{ValidBefore: NewTimeDuration(time.Now().Add(1 * time.Minute))},
 				cmp: SignSSHOptions{ValidBefore: NewTimeDuration(time.Now().Add(5 * time.Minute))},
-				err: errors.Errorf("ssh certificate valid before does not match"),
+				err: errors.Errorf("ssh certificate validBefore does not match"),
 			}
 		},
 		"ok/original-empty": func() test {
@@ -394,7 +394,7 @@ func Test_sshDefaultExtensionModifier_Modify(t *testing.T) {
 			return test{
 				modifier: sshDefaultExtensionModifier{},
 				cert:     cert,
-				err:      errors.New("ssh certificate type has not been set or is invalid"),
+				err:      errors.New("ssh certificate has an unknown type '3'"),
 			}
 		},
 		"ok/host": func() test {
@@ -518,7 +518,7 @@ func Test_sshCertDefaultValidator_Valid(t *testing.T) {
 			"fail/unexpected-cert-type",
 			// UserCert = 1, HostCert = 2
 			&ssh.Certificate{Nonce: []byte("foo"), Key: sshPub, CertType: 3, Serial: 1},
-			errors.New("ssh certificate has an unknown type: 3"),
+			errors.New("ssh certificate has an unknown type '3'"),
 		},
 		{
 			"fail/empty-cert-key-id",
@@ -725,7 +725,7 @@ func Test_sshCertValidityValidator(t *testing.T) {
 				ValidBefore: uint64(now().Add(10 * time.Minute).Unix()),
 			},
 			SignSSHOptions{},
-			errors.New("unknown ssh certificate type 3"),
+			errors.New("ssh certificate has an unknown type '3'"),
 		},
 		{
 			"fail/duration<min",

authority/ssh.go

@@ -9,7 +9,6 @@ import (
 	"strings"
 	"time"
 
-	"github.com/pkg/errors"
 	"github.com/smallstep/certificates/authority/config"
 	"github.com/smallstep/certificates/authority/provisioner"
 	"github.com/smallstep/certificates/db"
@@ -174,7 +173,7 @@ func (a *Authority) SignSSH(ctx context.Context, key ssh.PublicKey, opts provisi
 		// validate the given SSHOptions
 		case provisioner.SSHCertOptionsValidator:
 			if err := o.Valid(opts); err != nil {
-				return nil, errs.Wrap(http.StatusForbidden, err, "authority.SignSSH")
+				return nil, errs.BadRequestErr(err, "error validating ssh certificate options")
 			}
 
 		default:
@@ -214,7 +213,7 @@ func (a *Authority) SignSSH(ctx context.Context, key ssh.PublicKey, opts provisi
 	// Use provisioner modifiers.
 	for _, m := range mods {
 		if err := m.Modify(certTpl, opts); err != nil {
-			return nil, errs.Wrap(http.StatusForbidden, err, "authority.SignSSH")
+			return nil, errs.ForbiddenErr(err, "error creating ssh certificate")
 		}
 	}
 
@@ -244,7 +243,7 @@ func (a *Authority) SignSSH(ctx context.Context, key ssh.PublicKey, opts provisi
 	// User provisioners validators.
 	for _, v := range validators {
 		if err := v.Valid(cert, opts); err != nil {
-			return nil, errs.Wrap(http.StatusForbidden, err, "authority.SignSSH")
+			return nil, errs.ForbiddenErr(err, "error validating ssh certificate")
 		}
 	}
 
@@ -382,7 +381,7 @@ func (a *Authority) RekeySSH(ctx context.Context, oldCert *ssh.Certificate, pub
 	// Apply validators from provisioner.
 	for _, v := range validators {
 		if err := v.Valid(cert, provisioner.SignSSHOptions{Backdate: backdate}); err != nil {
-			return nil, errs.Wrap(http.StatusForbidden, err, "rekeySSH")
+			return nil, errs.ForbiddenErr(err, "error validating ssh certificate")
 		}
 	}
 
@@ -407,12 +406,12 @@ func (a *Authority) storeSSHCertificate(cert *ssh.Certificate) error {
 // the given certificate.
 func IsValidForAddUser(cert *ssh.Certificate) error {
 	if cert.CertType != ssh.UserCert {
-		return errors.New("certificate is not a user certificate")
+		return errs.Forbidden("certificate is not a user certificate")
 	}
 
 	switch len(cert.ValidPrincipals) {
 	case 0:
-		return errors.New("certificate does not have any principals")
+		return errs.Forbidden("certificate does not have any principals")
 	case 1:
 		return nil
 	case 2:
@@ -421,9 +420,9 @@ func IsValidForAddUser(cert *ssh.Certificate) error {
 		if strings.Index(cert.ValidPrincipals[1], "@") > 0 {
 			return nil
 		}
-		return errors.New("certificate does not have only one principal")
+		return errs.Forbidden("certificate does not have only one principal")
 	default:
-		return errors.New("certificate does not have only one principal")
+		return errs.Forbidden("certificate does not have only one principal")
 	}
 }
 
@@ -433,7 +432,7 @@ func (a *Authority) SignSSHAddUser(ctx context.Context, key ssh.PublicKey, subje
 		return nil, errs.NotImplemented("signSSHAddUser: user certificate signing is not enabled")
 	}
 	if err := IsValidForAddUser(subject); err != nil {
-		return nil, errs.Wrap(http.StatusForbidden, err, "signSSHAddUser")
+		return nil, err
 	}
 
 	nonce, err := randutil.ASCII(32)

authority/tls.go

@@ -94,7 +94,10 @@ func (a *Authority) Sign(csr *x509.CertificateRequest, signOpts provisioner.Sign
 		// Validate the given certificate request.
 		case provisioner.CertificateRequestValidator:
 			if err := k.Valid(csr); err != nil {
-				return nil, errs.Wrap(http.StatusUnauthorized, err, "authority.Sign", opts...)
+				return nil, errs.ApplyOptions(
+					errs.ForbiddenErr(err, "error validating certificate"),
+					opts...,
+				)
 			}
 
 		// Validates the unsigned certificate template.
@@ -131,26 +134,38 @@ func (a *Authority) Sign(csr *x509.CertificateRequest, signOpts provisioner.Sign
 
 	// Set default subject
 	if err := withDefaultASN1DN(a.config.AuthorityConfig.Template).Modify(leaf, signOpts); err != nil {
-		return nil, errs.Wrap(http.StatusUnauthorized, err, "authority.Sign", opts...)
+		return nil, errs.ApplyOptions(
+			errs.ForbiddenErr(err, "error creating certificate"),
+			opts...,
+		)
 	}
 
 	for _, m := range certModifiers {
 		if err := m.Modify(leaf, signOpts); err != nil {
-			return nil, errs.Wrap(http.StatusUnauthorized, err, "authority.Sign", opts...)
+			return nil, errs.ApplyOptions(
+				errs.ForbiddenErr(err, "error creating certificate"),
+				opts...,
+			)
 		}
 	}
 
 	// Certificate validation.
 	for _, v := range certValidators {
 		if err := v.Valid(leaf, signOpts); err != nil {
-			return nil, errs.Wrap(http.StatusUnauthorized, err, "authority.Sign", opts...)
+			return nil, errs.ApplyOptions(
+				errs.ForbiddenErr(err, "error validating certificate"),
+				opts...,
+			)
 		}
 	}
 
 	// Certificate modifiers after validation
 	for _, m := range certEnforcers {
 		if err := m.Enforce(leaf); err != nil {
-			return nil, errs.Wrap(http.StatusUnauthorized, err, "authority.Sign", opts...)
+			return nil, errs.ApplyOptions(
+				errs.ForbiddenErr(err, "error creating certificate"),
+				opts...,
+			)
 		}
 	}
 
@@ -328,6 +343,7 @@ type RevokeOptions struct {
 	ReasonCode  int
 	PassiveOnly bool
 	MTLS        bool
+	ACME        bool
 	Crt         *x509.Certificate
 	OTT         string
 }
@@ -345,9 +361,10 @@ func (a *Authority) Revoke(ctx context.Context, revokeOpts *RevokeOptions) error
 		errs.WithKeyVal("reason", revokeOpts.Reason),
 		errs.WithKeyVal("passiveOnly", revokeOpts.PassiveOnly),
 		errs.WithKeyVal("MTLS", revokeOpts.MTLS),
+		errs.WithKeyVal("ACME", revokeOpts.ACME),
 		errs.WithKeyVal("context", provisioner.MethodFromContext(ctx).String()),
 	}
-	if revokeOpts.MTLS {
+	if revokeOpts.MTLS || revokeOpts.ACME {
 		opts = append(opts, errs.WithKeyVal("certificate", base64.StdEncoding.EncodeToString(revokeOpts.Crt.Raw)))
 	} else {
 		opts = append(opts, errs.WithKeyVal("token", revokeOpts.OTT))
@@ -358,6 +375,7 @@ func (a *Authority) Revoke(ctx context.Context, revokeOpts *RevokeOptions) error
 		ReasonCode: revokeOpts.ReasonCode,
 		Reason:     revokeOpts.Reason,
 		MTLS:       revokeOpts.MTLS,
+		ACME:       revokeOpts.ACME,
 		RevokedAt:  time.Now().UTC(),
 	}
 
@@ -365,8 +383,8 @@ func (a *Authority) Revoke(ctx context.Context, revokeOpts *RevokeOptions) error
 		p   provisioner.Interface
 		err error
 	)
-	// If not mTLS then get the TokenID of the token.
+	// If not mTLS nor ACME, then get the TokenID of the token.
-	if !revokeOpts.MTLS {
+	if !(revokeOpts.MTLS || revokeOpts.ACME) {
 		token, err := jose.ParseSigned(revokeOpts.OTT)
 		if err != nil {
 			return errs.Wrap(http.StatusUnauthorized, err,

authority/tls_test.go

@@ -281,8 +281,8 @@ func TestAuthority_Sign(t *testing.T) {
 				csr:       csr,
 				extraOpts: extraOpts,
 				signOpts:  signOpts,
-				err:       errors.New("authority.Sign: default ASN1DN template cannot be nil"),
+				err:       errors.New("default ASN1DN template cannot be nil"),
-				code:      http.StatusUnauthorized,
+				code:      http.StatusForbidden,
 			}
 		},
 		"fail create cert": func(t *testing.T) *signTest {
@@ -309,8 +309,8 @@ func TestAuthority_Sign(t *testing.T) {
 				csr:       csr,
 				extraOpts: extraOpts,
 				signOpts:  _signOpts,
-				err:       errors.New("authority.Sign: requested duration of 25h0m0s is more than the authorized maximum certificate duration of 24h1m0s"),
+				err:       errors.New("requested duration of 25h0m0s is more than the authorized maximum certificate duration of 24h1m0s"),
-				code:      http.StatusBadRequest,
+				code:      http.StatusForbidden,
 			}
 		},
 		"fail validate sans when adding common name not in claims": func(t *testing.T) *signTest {
@@ -322,8 +322,8 @@ func TestAuthority_Sign(t *testing.T) {
 				csr:       csr,
 				extraOpts: extraOpts,
 				signOpts:  signOpts,
-				err:       errors.New("authority.Sign: certificate request does not contain the valid DNS names - got [test.smallstep.com smallstep test], want [test.smallstep.com]"),
+				err:       errors.New("certificate request does not contain the valid DNS names - got [test.smallstep.com smallstep test], want [test.smallstep.com]"),
-				code:      http.StatusUnauthorized,
+				code:      http.StatusForbidden,
 			}
 		},
 		"fail rsa key too short": func(t *testing.T) *signTest {
@@ -348,8 +348,8 @@ ZYtQ9Ot36qc=
 				csr:       csr,
 				extraOpts: extraOpts,
 				signOpts:  signOpts,
-				err:       errors.New("authority.Sign: rsa key in CSR must be at least 2048 bits (256 bytes)"),
+				err:       errors.New("certificate request RSA key must be at least 2048 bits (256 bytes)"),
-				code:      http.StatusUnauthorized,
+				code:      http.StatusForbidden,
 			}
 		},
 		"fail store cert in db": func(t *testing.T) *signTest {
@@ -1267,6 +1267,23 @@ func TestAuthority_Revoke(t *testing.T) {
 				},
 			}
 		},
+		"ok/ACME": func() test {
+			_a := testAuthority(t, WithDatabase(&db.MockAuthDB{}))
+
+			crt, err := pemutil.ReadCertificate("./testdata/certs/foo.crt")
+			assert.FatalError(t, err)
+
+			return test{
+				auth: _a,
+				opts: &RevokeOptions{
+					Crt:        crt,
+					Serial:     "102012593071130646873265215610956555026",
+					ReasonCode: reasonCode,
+					Reason:     reason,
+					ACME:       true,
+				},
+			}
+		},
 	}
 	for name, f := range tests {
 		tc := f()

ca/ca.go

@@ -442,7 +442,7 @@ func (ca *CA) getTLSConfig(auth *authority.Authority) (*tls.Config, error) {
 	return tlsConfig, nil
 }
 
-// shouldMountSCEPEndpoints returns if the CA should be
+// shouldServeSCEPEndpoints returns if the CA should be
 // configured with endpoints for SCEP. This is assumed to be
 // true if a SCEPService exists, which is true in case a
 // SCEP provisioner was configured.

ca/ca_test.go

@@ -200,8 +200,8 @@ ZEp7knvU2psWRw==
 			return &signTest{
 				ca:     ca,
 				body:   string(body),
-				status: http.StatusUnauthorized,
+				status: http.StatusForbidden,
-				errMsg: errs.UnauthorizedDefaultMsg,
+				errMsg: errs.ForbiddenPrefix,
 			}
 		},
 		"ok": func(t *testing.T) *signTest {

db/db.go

@@ -104,6 +104,7 @@ type RevokedCertificateInfo struct {
 	RevokedAt     time.Time
 	TokenID       string
 	MTLS          bool
+	ACME          bool
 }
 
 // IsRevoked returns whether or not a certificate with the given identifier

errs/error.go

@@ -169,7 +169,8 @@ func StatusCodeError(code int, e error, opts ...Option) error {
 	case http.StatusUnauthorized:
 		return UnauthorizedErr(e, opts...)
 	case http.StatusForbidden:
-		return ForbiddenErr(e, opts...)
+		opts = append(opts, withDefaultMessage(ForbiddenDefaultMsg))
+		return NewErr(http.StatusForbidden, e, opts...)
 	case http.StatusInternalServerError:
 		return InternalServerErr(e, opts...)
 	case http.StatusNotImplemented:
@@ -199,12 +200,18 @@ var (
 	// BadRequestPrefix is the prefix added to the bad request messages that are
 	// directly sent to the cli.
 	BadRequestPrefix = "The request could not be completed: "
+
+	// ForbiddenPrefix is the prefix added to the forbidden messates that are
+	// sent to the cli.
+	ForbiddenPrefix = "The request was forbidden by the certificate authority: "
 )
 
 func formatMessage(status int, msg string) string {
 	switch status {
 	case http.StatusBadRequest:
 		return BadRequestPrefix + msg + "."
+	case http.StatusForbidden:
+		return ForbiddenPrefix + msg + "."
 	default:
 		return msg
 	}
@@ -356,14 +363,12 @@ func UnauthorizedErr(err error, opts ...Option) error {
 
 // Forbidden creates a 403 error with the given format and arguments.
 func Forbidden(format string, args ...interface{}) error {
-	args = append(args, withDefaultMessage(ForbiddenDefaultMsg))
+	return New(http.StatusForbidden, format, args...)
-	return Errorf(http.StatusForbidden, format, args...)
 }
 
 // ForbiddenErr returns an 403 error with the given error.
-func ForbiddenErr(err error, opts ...Option) error {
+func ForbiddenErr(err error, format string, args ...interface{}) error {
-	opts = append(opts, withDefaultMessage(ForbiddenDefaultMsg))
+	return NewError(http.StatusForbidden, err, format, args...)
-	return NewErr(http.StatusForbidden, err, opts...)
 }
 
 // NotFound creates a 404 error with the given format and arguments.

go.mod

@@ -18,6 +18,7 @@ require (
 	github.com/go-kit/kit v0.10.0 // indirect
 	github.com/go-piv/piv-go v1.7.0
 	github.com/golang/mock v1.6.0
+	github.com/google/go-cmp v0.5.6
 	github.com/google/uuid v1.3.0
 	github.com/googleapis/gax-go/v2 v2.0.5
 	github.com/konsorten/go-windows-terminal-sequences v1.0.2 // indirect