feat: add support for signing blob (#379)

This PR adds support for signing blobs.

Signed-off-by: Pritesh Bandi <priteshbandi@gmail.com>

example_localSign_test.go

@@ -47,8 +47,8 @@ func Example_localSign() {
 	// Users should replace `exampleCertTuple.PrivateKey` with their own private
 	// key and replace `exampleCerts` with the corresponding full certificate
 	// chain, following the Notary certificate requirements:
-	// https://github.com/notaryproject/notaryproject/blob/v1.0.0-rc.1/specs/signature-specification.md#certificate-requirements
-	exampleSigner, err := signer.New(exampleCertTuple.PrivateKey, exampleCerts)
+	// https://github.com/notaryproject/notaryproject/blob/v1.0.0/specs/signature-specification.md#certificate-requirements
+	exampleSigner, err := signer.NewGenericSigner(exampleCertTuple.PrivateKey, exampleCerts)
 	if err != nil {
 		panic(err) // Handle error
 	}

example_remoteSign_test.go

@@ -18,12 +18,13 @@ import (
 	"crypto/x509"
 	"fmt"
 
+	"oras.land/oras-go/v2/registry/remote"
+
 	"github.com/notaryproject/notation-core-go/signature/cose"
 	"github.com/notaryproject/notation-core-go/testhelper"
 	"github.com/notaryproject/notation-go"
 	"github.com/notaryproject/notation-go/registry"
 	"github.com/notaryproject/notation-go/signer"
-	"oras.land/oras-go/v2/registry/remote"
 )
 
 // Both COSE ("application/cose") and JWS ("application/jose+json")
@@ -45,8 +46,8 @@ func Example_remoteSign() {
 	// Users should replace `exampleCertTuple.PrivateKey` with their own private
 	// key and replace `exampleCerts` with the corresponding full certificate
 	// chain, following the Notary certificate requirements:
-	// https://github.com/notaryproject/notaryproject/blob/v1.0.0-rc.1/specs/signature-specification.md#certificate-requirements
-	exampleSigner, err := signer.New(exampleCertTuple.PrivateKey, exampleCerts)
+	// https://github.com/notaryproject/notaryproject/blob/v1.0.0/specs/signature-specification.md#certificate-requirements
+	exampleSigner, err := signer.NewGenericSigner(exampleCertTuple.PrivateKey, exampleCerts)
 	if err != nil {
 		panic(err) // Handle error
 	}

notation.go

@@ -22,17 +22,22 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"io"
+	"mime"
 	"strings"
 	"time"
 
+	orasRegistry "oras.land/oras-go/v2/registry"
+
 	"github.com/notaryproject/notation-core-go/signature"
+	"github.com/notaryproject/notation-core-go/signature/cose"
+	"github.com/notaryproject/notation-core-go/signature/jws"
 	"github.com/notaryproject/notation-go/internal/envelope"
 	"github.com/notaryproject/notation-go/log"
 	"github.com/notaryproject/notation-go/registry"
 	"github.com/notaryproject/notation-go/verifier/trustpolicy"
 	"github.com/opencontainers/go-digest"
 	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
-	orasRegistry "oras.land/oras-go/v2/registry"
 )
 
 var errDoneVerification = errors.New("done verification")
@@ -41,7 +46,7 @@ var reservedAnnotationPrefixes = [...]string{"io.cncf.notary"}
 // SignerSignOptions contains parameters for Signer.Sign.
 type SignerSignOptions struct {
 	// SignatureMediaType is the envelope type of the signature.
-	// Currently both `application/jose+json` and `application/cose` are
+	// Currently, both `application/jose+json` and `application/cose` are
 	// supported.
 	SignatureMediaType string
 
@@ -56,15 +61,37 @@ type SignerSignOptions struct {
 	SigningAgent string
 }
 
-// Signer is a generic interface for signing an artifact.
+// Signer is a generic interface for signing an OCI artifact.
 // The interface allows signing with local or remote keys,
 // and packing in various signature formats.
 type Signer interface {
-	// Sign signs the artifact described by its descriptor,
+	// Sign signs the OCI artifact described by its descriptor,
 	// and returns the signature and SignerInfo.
 	Sign(ctx context.Context, desc ocispec.Descriptor, opts SignerSignOptions) ([]byte, *signature.SignerInfo, error)
 }
 
+// SignBlobOptions contains parameters for notation.SignBlob.
+type SignBlobOptions struct {
+	SignerSignOptions
+	// ContentMediaType is the media-type of the blob being signed.
+	ContentMediaType string
+	// UserMetadata contains key-value pairs that are added to the signature
+	// payload
+	UserMetadata map[string]string
+}
+
+// BlobDescriptorGenerator creates descriptor using the digest Algorithm.
+type BlobDescriptorGenerator func(digest.Algorithm) (ocispec.Descriptor, error)
+
+// BlobSigner is a generic interface for signing arbitrary data.
+// The interface allows signing with local or remote keys,
+// and packing in various signature formats.
+type BlobSigner interface {
+	// SignBlob signs the descriptor returned by genDesc ,
+	// and returns the signature and SignerInfo
+	SignBlob(ctx context.Context, genDesc BlobDescriptorGenerator, opts SignerSignOptions) ([]byte, *signature.SignerInfo, error)
+}
+
 // signerAnnotation facilitates return of manifest annotations by signers
 type signerAnnotation interface {
 	// PluginAnnotations returns signature manifest annotations returned from
@@ -85,22 +112,16 @@ type SignOptions struct {
 	UserMetadata map[string]string
 }
 
-// Sign signs the artifact and push the signature to the Repository.
-// The descriptor of the sign content is returned upon sucessful signing.
+// Sign signs the OCI artifact and push the signature to the Repository.
+// The descriptor of the sign content is returned upon successful signing.
 func Sign(ctx context.Context, signer Signer, repo registry.Repository, signOpts SignOptions) (ocispec.Descriptor, error) {
 	// sanity check
-	if signer == nil {
-		return ocispec.Descriptor{}, errors.New("signer cannot be nil")
+	if err := validateSignArguments(signer, signOpts.SignerSignOptions); err != nil {
+		return ocispec.Descriptor{}, err
 	}
 	if repo == nil {
 		return ocispec.Descriptor{}, errors.New("repo cannot be nil")
 	}
-	if signOpts.ExpiryDuration < 0 {
-		return ocispec.Descriptor{}, fmt.Errorf("expiry duration cannot be a negative value")
-	}
-	if signOpts.ExpiryDuration%time.Second != 0 {
-		return ocispec.Descriptor{}, fmt.Errorf("expiry duration supports minimum granularity of seconds")
-	}
 
 	logger := log.GetLogger(ctx)
 	artifactRef := signOpts.ArtifactReference
@@ -152,6 +173,50 @@ func Sign(ctx context.Context, signer Signer, repo registry.Repository, signOpts
 	return targetDesc, nil
 }
 
+// SignBlob signs the arbitrary data and returns the signature
+func SignBlob(ctx context.Context, signer BlobSigner, blobReader io.Reader, signBlobOpts SignBlobOptions) ([]byte, *signature.SignerInfo, error) {
+	// sanity checks
+	if err := validateSignArguments(signer, signBlobOpts.SignerSignOptions); err != nil {
+		return nil, nil, err
+	}
+
+	if blobReader == nil {
+		return nil, nil, errors.New("blobReader cannot be nil")
+	}
+
+	if signBlobOpts.ContentMediaType == "" {
+		return nil, nil, errors.New("content media-type cannot be empty")
+	}
+
+	if _, _, err := mime.ParseMediaType(signBlobOpts.ContentMediaType); err != nil {
+		return nil, nil, fmt.Errorf("invalid content media-type '%s': %v", signBlobOpts.ContentMediaType, err)
+	}
+
+	getDescFunc := getDescriptorFunc(ctx, blobReader, signBlobOpts.ContentMediaType, signBlobOpts.UserMetadata)
+	return signer.SignBlob(ctx, getDescFunc, signBlobOpts.SignerSignOptions)
+}
+
+func validateSignArguments(signer any, signOpts SignerSignOptions) error {
+	if signer == nil {
+		return errors.New("signer cannot be nil")
+	}
+	if signOpts.ExpiryDuration < 0 {
+		return errors.New("expiry duration cannot be a negative value")
+	}
+	if signOpts.ExpiryDuration%time.Second != 0 {
+		return errors.New("expiry duration supports minimum granularity of seconds")
+	}
+	if signOpts.SignatureMediaType == "" {
+		return errors.New("signature media-type cannot be empty")
+	}
+
+	if !(signOpts.SignatureMediaType == jws.MediaTypeEnvelope || signOpts.SignatureMediaType == cose.MediaTypeEnvelope) {
+		return fmt.Errorf("invalid signature media-type '%s'", signOpts.SignatureMediaType)
+	}
+
+	return nil
+}
+
 func addUserMetadataToDescriptor(ctx context.Context, desc ocispec.Descriptor, userMetadata map[string]string) (ocispec.Descriptor, error) {
 	logger := log.GetLogger(ctx)
 
@@ -236,7 +301,7 @@ func (outcome *VerificationOutcome) UserMetadata() (map[string]string, error) {
 
 // VerifierVerifyOptions contains parameters for Verifier.Verify.
 type VerifierVerifyOptions struct {
-	// ArtifactReference is the reference of the artifact that is been
+	// ArtifactReference is the reference of the artifact that is being
 	// verified against to. It must be a full reference.
 	ArtifactReference string
 
@@ -270,7 +335,7 @@ type verifySkipper interface {
 
 // VerifyOptions contains parameters for notation.Verify.
 type VerifyOptions struct {
-	// ArtifactReference is the reference of the artifact that is been
+	// ArtifactReference is the reference of the artifact that is being
 	// verified against to.
 	ArtifactReference string
 
@@ -449,3 +514,19 @@ func generateAnnotations(signerInfo *signature.SignerInfo, annotations map[strin
 	annotations[ocispec.AnnotationCreated] = signingTime.Format(time.RFC3339)
 	return annotations, nil
 }
+
+func getDescriptorFunc(ctx context.Context, reader io.Reader, contentMediaType string, userMetadata map[string]string) BlobDescriptorGenerator {
+	return func(hashAlgo digest.Algorithm) (ocispec.Descriptor, error) {
+		digester := hashAlgo.Digester()
+		bytes, err := io.Copy(digester.Hash(), reader)
+		if err != nil {
+			return ocispec.Descriptor{}, err
+		}
+		targetDesc := ocispec.Descriptor{
+			MediaType: contentMediaType,
+			Digest:    digester.Digest(),
+			Size:      bytes,
+		}
+		return addUserMetadataToDescriptor(ctx, targetDesc, userMetadata)
+	}
+}

notation_test.go

@@ -17,18 +17,22 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"io"
 	"math"
 	"os"
 	"path/filepath"
+	"strings"
 	"testing"
 	"time"
 
 	"github.com/notaryproject/notation-core-go/signature"
 	"github.com/notaryproject/notation-core-go/signature/cose"
+	"github.com/notaryproject/notation-core-go/signature/jws"
 	"github.com/notaryproject/notation-go/internal/mock"
 	"github.com/notaryproject/notation-go/plugin"
 	"github.com/notaryproject/notation-go/registry"
 	"github.com/notaryproject/notation-go/verifier/trustpolicy"
+	"github.com/opencontainers/go-digest"
 	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
 )
 
@@ -47,6 +51,7 @@ func TestSignSuccess(t *testing.T) {
 	for _, tc := range testCases {
 		t.Run(tc.name, func(b *testing.T) {
 			opts := SignOptions{}
+			opts.SignatureMediaType = jws.MediaTypeEnvelope
 			opts.ExpiryDuration = tc.dur
 			opts.ArtifactReference = mock.SampleArtifactUri
 
@@ -58,11 +63,91 @@ func TestSignSuccess(t *testing.T) {
 	}
 }
 
+func TestSignBlobSuccess(t *testing.T) {
+	reader := strings.NewReader("some content")
+	testCases := []struct {
+		name     string
+		dur      time.Duration
+		mtype    string
+		agent    string
+		pConfig  map[string]string
+		metadata map[string]string
+	}{
+		{"expiryInHours", 24 * time.Hour, "video/mp4", "", nil, nil},
+		{"oneSecondExpiry", 1 * time.Second, "video/mp4", "", nil, nil},
+		{"zeroExpiry", 0, "video/mp4", "", nil, nil},
+		{"validContentType", 1 * time.Second, "video/mp4", "", nil, nil},
+		{"emptyContentType", 1 * time.Second, "video/mp4", "someDummyAgent", map[string]string{"hi": "hello"}, map[string]string{"bye": "tata"}},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.name, func(b *testing.T) {
+			opts := SignBlobOptions{
+				SignerSignOptions: SignerSignOptions{
+					SignatureMediaType: jws.MediaTypeEnvelope,
+					ExpiryDuration:     tc.dur,
+					PluginConfig:       tc.pConfig,
+					SigningAgent:       tc.agent,
+				},
+				UserMetadata:     expectedMetadata,
+				ContentMediaType: tc.mtype,
+			}
+
+			_, _, err := SignBlob(context.Background(), &dummySigner{}, reader, opts)
+			if err != nil {
+				b.Fatalf("Sign failed with error: %v", err)
+			}
+		})
+	}
+}
+
+func TestSignBlobError(t *testing.T) {
+	reader := strings.NewReader("some content")
+	testCases := []struct {
+		name     string
+		signer   BlobSigner
+		dur      time.Duration
+		rdr      io.Reader
+		sigMType string
+		ctMType  string
+		errMsg   string
+	}{
+		{"negativeExpiry", &dummySigner{}, -1 * time.Second, nil, "video/mp4", jws.MediaTypeEnvelope, "expiry duration cannot be a negative value"},
+		{"milliSecExpiry", &dummySigner{}, 1 * time.Millisecond, nil, "video/mp4", jws.MediaTypeEnvelope, "expiry duration supports minimum granularity of seconds"},
+		{"invalidContentMediaType", &dummySigner{}, 1 * time.Second, reader, "video/mp4/zoping", jws.MediaTypeEnvelope, "invalid content media-type 'video/mp4/zoping': mime: unexpected content after media subtype"},
+		{"emptyContentMediaType", &dummySigner{}, 1 * time.Second, reader, "", jws.MediaTypeEnvelope, "content media-type cannot be empty"},
+		{"invalidSignatureMediaType", &dummySigner{}, 1 * time.Second, reader, "", "", "content media-type cannot be empty"},
+		{"nilReader", &dummySigner{}, 1 * time.Second, nil, "video/mp4", jws.MediaTypeEnvelope, "blobReader cannot be nil"},
+		{"nilSigner", nil, 1 * time.Second, reader, "video/mp4", jws.MediaTypeEnvelope, "signer cannot be nil"},
+		{"signerError", &dummySigner{fail: true}, 1 * time.Second, reader, "video/mp4", jws.MediaTypeEnvelope, "expected SignBlob failure"},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			opts := SignBlobOptions{
+				SignerSignOptions: SignerSignOptions{
+					SignatureMediaType: jws.MediaTypeEnvelope,
+					ExpiryDuration:     tc.dur,
+					PluginConfig:       nil,
+				},
+				ContentMediaType: tc.sigMType,
+			}
+
+			_, _, err := SignBlob(context.Background(), tc.signer, tc.rdr, opts)
+			if err == nil {
+				t.Fatalf("expected error but didnt found")
+			}
+			if err.Error() != tc.errMsg {
+				t.Fatalf("expected err message to be '%s' but found '%s'", tc.errMsg, err.Error())
+			}
+		})
+	}
+}
+
 func TestSignSuccessWithUserMetadata(t *testing.T) {
 	repo := mock.NewRepository()
 	opts := SignOptions{}
 	opts.ArtifactReference = mock.SampleArtifactUri
 	opts.UserMetadata = expectedMetadata
+	opts.SignatureMediaType = jws.MediaTypeEnvelope
 
 	_, err := Sign(context.Background(), &verifyMetadataSigner{}, repo, opts)
 	if err != nil {
@@ -182,6 +267,9 @@ func TestSignDigestNotMatchResolve(t *testing.T) {
 	repo := mock.NewRepository()
 	repo.MissMatchDigest = true
 	signOpts := SignOptions{
+		SignerSignOptions: SignerSignOptions{
+			SignatureMediaType: jws.MediaTypeEnvelope,
+		},
 		ArtifactReference: mock.SampleArtifactUri,
 	}
 
@@ -320,7 +408,9 @@ func dummyPolicyStatement() (policyStatement trustpolicy.TrustPolicy) {
 	return
 }
 
-type dummySigner struct{}
+type dummySigner struct {
+	fail bool
+}
 
 func (s *dummySigner) Sign(ctx context.Context, desc ocispec.Descriptor, opts SignerSignOptions) ([]byte, *signature.SignerInfo, error) {
 	return []byte("ABC"), &signature.SignerInfo{
@@ -330,6 +420,23 @@ func (s *dummySigner) Sign(ctx context.Context, desc ocispec.Descriptor, opts Si
 	}, nil
 }
 
+func (s *dummySigner) SignBlob(_ context.Context, descGenFunc BlobDescriptorGenerator, _ SignerSignOptions) ([]byte, *signature.SignerInfo, error) {
+	if s.fail {
+		return nil, nil, errors.New("expected SignBlob failure")
+	}
+
+	_, err := descGenFunc(digest.SHA384)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	return []byte("ABC"), &signature.SignerInfo{
+		SignedAttributes: signature.SignedAttributes{
+			SigningTime: time.Now(),
+		},
+	}, nil
+}
+
 type verifyMetadataSigner struct{}
 
 func (s *verifyMetadataSigner) Sign(ctx context.Context, desc ocispec.Descriptor, opts SignerSignOptions) ([]byte, *signature.SignerInfo, error) {