Export Fulcio extension OIDs

pkg/ca/baseca/baseca_test.go

@@ -27,6 +27,7 @@ import (
 
 	ct "github.com/google/certificate-transparency-go"
 	"github.com/sigstore/fulcio/pkg/ca"
+	"github.com/sigstore/fulcio/pkg/certificate"
 	"github.com/sigstore/fulcio/pkg/test"
 	"github.com/sigstore/sigstore/pkg/cryptoutils"
 	"github.com/sigstore/sigstore/pkg/signature"
@@ -92,7 +93,7 @@ func (tp testPrincipal) Name(context.Context) string {
 
 func (tp testPrincipal) Embed(ctx context.Context, cert *x509.Certificate) (err error) {
 	cert.EmailAddresses = []string{"alice@example.com"}
-	cert.ExtraExtensions, err = ca.Extensions{
+	cert.ExtraExtensions, err = certificate.Extensions{
 		Issuer: "example.com",
 	}.Render()
 	return

pkg/certificate/doc.go

@@ -0,0 +1,17 @@
+// Copyright 2022 The Sigstore Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package certificate contains helpers for getting data from Fulcio issued
+// x509 certificates.
+package certificate

pkg/ca/extensions.go → pkg/certificate/extensions.go

@@ -12,14 +12,23 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package ca
+package certificate
 
 import (
 	"crypto/x509/pkix"
 	"encoding/asn1"
 	"errors"
 )
 
+var (
+	OIDIssuer                   = asn1.ObjectIdentifier{1, 3, 6, 1, 4, 1, 57264, 1, 1}
+	OIDGitHubWorkflowTrigger    = asn1.ObjectIdentifier{1, 3, 6, 1, 4, 1, 57264, 1, 2}
+	OIDGitHubWorkflowSHA        = asn1.ObjectIdentifier{1, 3, 6, 1, 4, 1, 57264, 1, 3}
+	OIDGitHubWorkflowName       = asn1.ObjectIdentifier{1, 3, 6, 1, 4, 1, 57264, 1, 4}
+	OIDGitHubWorkflowRepository = asn1.ObjectIdentifier{1, 3, 6, 1, 4, 1, 57264, 1, 5}
+	OIDGitHubWorkflowRef        = asn1.ObjectIdentifier{1, 3, 6, 1, 4, 1, 57264, 1, 6}
+)
+
 // Extensions contains all custom x509 extensions defined by Fulcio
 type Extensions struct {
 	// NB: New extensions must be added here and documented
@@ -57,41 +66,66 @@ func (e Extensions) Render() ([]pkix.Extension, error) {
 
 	if e.Issuer != "" {
 		exts = append(exts, pkix.Extension{
-			Id:    asn1.ObjectIdentifier{1, 3, 6, 1, 4, 1, 57264, 1, 1},
+			Id:    OIDIssuer,
 			Value: []byte(e.Issuer),
 		})
 	} else {
 		return nil, errors.New("extensions must have a non-empty issuer url")
 	}
 	if e.GithubWorkflowTrigger != "" {
 		exts = append(exts, pkix.Extension{
-			Id:    asn1.ObjectIdentifier{1, 3, 6, 1, 4, 1, 57264, 1, 2},
+			Id:    OIDGitHubWorkflowTrigger,
 			Value: []byte(e.GithubWorkflowTrigger),
 		})
 	}
 	if e.GithubWorkflowSHA != "" {
 		exts = append(exts, pkix.Extension{
-			Id:    asn1.ObjectIdentifier{1, 3, 6, 1, 4, 1, 57264, 1, 3},
+			Id:    OIDGitHubWorkflowSHA,
 			Value: []byte(e.GithubWorkflowSHA),
 		})
 	}
 	if e.GithubWorkflowName != "" {
 		exts = append(exts, pkix.Extension{
-			Id:    asn1.ObjectIdentifier{1, 3, 6, 1, 4, 1, 57264, 1, 4},
+			Id:    OIDGitHubWorkflowName,
 			Value: []byte(e.GithubWorkflowName),
 		})
 	}
 	if e.GithubWorkflowRepository != "" {
 		exts = append(exts, pkix.Extension{
-			Id:    asn1.ObjectIdentifier{1, 3, 6, 1, 4, 1, 57264, 1, 5},
+			Id:    OIDGitHubWorkflowRepository,
 			Value: []byte(e.GithubWorkflowRepository),
 		})
 	}
 	if e.GithubWorkflowRef != "" {
 		exts = append(exts, pkix.Extension{
-			Id:    asn1.ObjectIdentifier{1, 3, 6, 1, 4, 1, 57264, 1, 6},
+			Id:    OIDGitHubWorkflowRef,
 			Value: []byte(e.GithubWorkflowRef),
 		})
 	}
 	return exts, nil
 }
+
+func ParseExtensions(ext []pkix.Extension) (Extensions, error) {
+	out := Extensions{}
+
+	for _, e := range ext {
+		switch {
+		case e.Id.Equal(OIDIssuer):
+			out.Issuer = string(e.Value)
+		case e.Id.Equal(OIDGitHubWorkflowTrigger):
+			out.GithubWorkflowTrigger = string(e.Value)
+		case e.Id.Equal(OIDGitHubWorkflowSHA):
+			out.GithubWorkflowSHA = string(e.Value)
+		case e.Id.Equal(OIDGitHubWorkflowName):
+			out.GithubWorkflowName = string(e.Value)
+		case e.Id.Equal(OIDGitHubWorkflowRepository):
+			out.GithubWorkflowRepository = string(e.Value)
+		case e.Id.Equal(OIDGitHubWorkflowRef):
+			out.GithubWorkflowRef = string(e.Value)
+		}
+	}
+
+	// We only ever return nil, but leaving error in place so that we can add
+	// more complex parsing of fields in a backwards compatible way if needed.
+	return out, nil
+}

pkg/ca/extensions_test.go → pkg/certificate/extensions_test.go

@@ -12,17 +12,17 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package ca
+package certificate
 
 import (
-	"bytes"
 	"crypto/x509/pkix"
-	"encoding/asn1"
 
 	"testing"
+
+	"github.com/google/go-cmp/cmp"
 )
 
-func TestRenderExtensions(t *testing.T) {
+func TestExtensions(t *testing.T) {
 	tests := map[string]struct {
 		Extensions Extensions
 		Expect     []pkix.Extension
@@ -45,27 +45,27 @@ func TestRenderExtensions(t *testing.T) {
 			},
 			Expect: []pkix.Extension{
 				{
-					Id:    asn1.ObjectIdentifier{1, 3, 6, 1, 4, 1, 57264, 1, 1},
+					Id:    OIDIssuer,
 					Value: []byte(`1`),
 				},
 				{
-					Id:    asn1.ObjectIdentifier{1, 3, 6, 1, 4, 1, 57264, 1, 2},
+					Id:    OIDGitHubWorkflowTrigger,
 					Value: []byte(`2`),
 				},
 				{
-					Id:    asn1.ObjectIdentifier{1, 3, 6, 1, 4, 1, 57264, 1, 3},
+					Id:    OIDGitHubWorkflowSHA,
 					Value: []byte(`3`),
 				},
 				{
-					Id:    asn1.ObjectIdentifier{1, 3, 6, 1, 4, 1, 57264, 1, 4},
+					Id:    OIDGitHubWorkflowName,
 					Value: []byte(`4`),
 				},
 				{
-					Id:    asn1.ObjectIdentifier{1, 3, 6, 1, 4, 1, 57264, 1, 5},
+					Id:    OIDGitHubWorkflowRepository,
 					Value: []byte(`5`),
 				},
 				{
-					Id:    asn1.ObjectIdentifier{1, 3, 6, 1, 4, 1, 57264, 1, 6},
+					Id:    OIDGitHubWorkflowRef,
 					Value: []byte(`6`),
 				},
 			},
@@ -75,25 +75,24 @@ func TestRenderExtensions(t *testing.T) {
 
 	for name, test := range tests {
 		t.Run(name, func(t *testing.T) {
-			got, err := test.Extensions.Render()
+			render, err := test.Extensions.Render()
 			if err != nil {
 				if !test.WantErr {
 					t.Error("Failed to render with unexpected error", err)
 				} else {
 					return
 				}
 			}
-			if len(got) != len(test.Expect) {
-				t.Errorf("Got %d extensions when rendered and expected %d", len(got), len(test.Expect))
-				return
+			if diff := cmp.Diff(test.Expect, render); diff != "" {
+				t.Errorf("Render: %s", diff)
 			}
-			for i, ext := range got {
-				if !ext.Id.Equal(test.Expect[i].Id) {
-					t.Errorf("Got OID %v in extension %d and expected %v", ext.Id, i, test.Expect[i].Id)
-				}
-				if !bytes.Equal(ext.Value, test.Expect[i].Value) {
-					t.Errorf("Expected extension value to be %s but got %s", test.Expect[i].Value, ext.Value)
-				}
+
+			parse, err := ParseExtensions(render)
+			if err != nil {
+				t.Fatalf("ParseExtensions: err = %v", err)
+			}
+			if diff := cmp.Diff(test.Extensions, parse); diff != "" {
+				t.Errorf("ParseExtensions: %s", diff)
 			}
 		})
 	}

pkg/identity/email/principal.go

@@ -20,7 +20,7 @@ import (
 	"errors"
 
 	"github.com/coreos/go-oidc/v3/oidc"
-	"github.com/sigstore/fulcio/pkg/ca"
+	"github.com/sigstore/fulcio/pkg/certificate"
 	"github.com/sigstore/fulcio/pkg/config"
 	"github.com/sigstore/fulcio/pkg/identity"
 	"github.com/sigstore/fulcio/pkg/oauthflow"
@@ -64,7 +64,7 @@ func (p principal) Embed(ctx context.Context, cert *x509.Certificate) error {
 	cert.EmailAddresses = []string{p.address}
 
 	var err error
-	cert.ExtraExtensions, err = ca.Extensions{
+	cert.ExtraExtensions, err = certificate.Extensions{
 		Issuer: p.issuer,
 	}.Render()
 	if err != nil {

pkg/identity/github/principal.go

@@ -21,7 +21,7 @@ import (
 	"net/url"
 
 	"github.com/coreos/go-oidc/v3/oidc"
-	"github.com/sigstore/fulcio/pkg/ca"
+	"github.com/sigstore/fulcio/pkg/certificate"
 	"github.com/sigstore/fulcio/pkg/identity"
 )
 
@@ -111,7 +111,7 @@ func (w workflowPrincipal) Embed(ctx context.Context, cert *x509.Certificate) er
 	cert.URIs = []*url.URL{parsed}
 
 	// Embed additional information into custom extensions
-	cert.ExtraExtensions, err = ca.Extensions{
+	cert.ExtraExtensions, err = certificate.Extensions{
 		Issuer:                   w.issuer,
 		GithubWorkflowTrigger:    w.trigger,
 		GithubWorkflowSHA:        w.sha,

pkg/identity/kubernetes/principal.go

@@ -20,7 +20,7 @@ import (
 	"net/url"
 
 	"github.com/coreos/go-oidc/v3/oidc"
-	"github.com/sigstore/fulcio/pkg/ca"
+	"github.com/sigstore/fulcio/pkg/certificate"
 	"github.com/sigstore/fulcio/pkg/identity"
 )
 
@@ -59,7 +59,7 @@ func (p principal) Embed(ctx context.Context, cert *x509.Certificate) error {
 	}
 	cert.URIs = []*url.URL{parsed}
 
-	cert.ExtraExtensions, err = ca.Extensions{
+	cert.ExtraExtensions, err = certificate.Extensions{
 		Issuer: p.issuer,
 	}.Render()
 	if err != nil {

pkg/identity/spiffe/principal.go

@@ -22,7 +22,7 @@ import (
 	"net/url"
 
 	"github.com/coreos/go-oidc/v3/oidc"
-	"github.com/sigstore/fulcio/pkg/ca"
+	"github.com/sigstore/fulcio/pkg/certificate"
 	"github.com/sigstore/fulcio/pkg/config"
 	"github.com/sigstore/fulcio/pkg/identity"
 	"github.com/spiffe/go-spiffe/v2/spiffeid"
@@ -82,7 +82,7 @@ func (p principal) Embed(ctx context.Context, cert *x509.Certificate) error {
 	}
 	cert.URIs = []*url.URL{parsed}
 
-	cert.ExtraExtensions, err = ca.Extensions{
+	cert.ExtraExtensions, err = certificate.Extensions{
 		Issuer: p.issuer,
 	}.Render()
 	if err != nil {

pkg/identity/uri/principal.go

@@ -22,7 +22,7 @@ import (
 	"net/url"
 
 	"github.com/coreos/go-oidc/v3/oidc"
-	"github.com/sigstore/fulcio/pkg/ca"
+	"github.com/sigstore/fulcio/pkg/certificate"
 	"github.com/sigstore/fulcio/pkg/config"
 	"github.com/sigstore/fulcio/pkg/identity"
 )
@@ -73,7 +73,7 @@ func (p principal) Embed(ctx context.Context, cert *x509.Certificate) error {
 	}
 	cert.URIs = []*url.URL{subjectURI}
 
-	cert.ExtraExtensions, err = ca.Extensions{
+	cert.ExtraExtensions, err = certificate.Extensions{
 		Issuer: p.issuer,
 	}.Render()
 	if err != nil {

pkg/identity/username/principal.go

@@ -22,7 +22,7 @@ import (
 	"strings"
 
 	"github.com/coreos/go-oidc/v3/oidc"
-	"github.com/sigstore/fulcio/pkg/ca"
+	"github.com/sigstore/fulcio/pkg/certificate"
 	"github.com/sigstore/fulcio/pkg/config"
 	"github.com/sigstore/fulcio/pkg/identity"
 )
@@ -62,7 +62,7 @@ func (p principal) Embed(ctx context.Context, cert *x509.Certificate) error {
 	cert.EmailAddresses = []string{p.emailAddress}
 
 	var err error
-	cert.ExtraExtensions, err = ca.Extensions{
+	cert.ExtraExtensions, err = certificate.Extensions{
 		Issuer: p.issuer,
 	}.Render()
 	if err != nil {