feat: add support for signed user metadata in notation sign and verify cmds

cmd/notation/key.go

@@ -163,7 +163,7 @@ func addKey(ctx context.Context, opts *keyAddOpts) error {
 	// set log level
 	ctx = opts.LoggingFlagOpts.SetLoggerLevel(ctx)
 
-	pluginConfig, err := cmd.ParseFlagPluginConfig(opts.pluginConfig)
+	pluginConfig, err := cmd.ParseFlagMap(opts.pluginConfig, cmd.PflagPluginConfig.Name)
 	if err != nil {
 		return err
 	}

cmd/notation/sign.go

@@ -22,6 +22,7 @@ type signOpts struct {
 	SecureFlagOpts
 	expiry       time.Duration
 	pluginConfig []string
+	userMetadata []string
 	reference    string
 }
 
@@ -67,6 +68,7 @@ Example - Sign an OCI artifact stored in a registry and specify the signature ex
 	opts.SecureFlagOpts.ApplyFlags(command.Flags())
 	cmd.SetPflagExpiry(command.Flags(), &opts.expiry)
 	cmd.SetPflagPluginConfig(command.Flags(), &opts.pluginConfig)
+	cmd.SetPflagUserMetadata(command.Flags(), &opts.userMetadata, cmd.PflagUserMetadataSignUsage)
 	return command
 }
 
@@ -99,29 +101,35 @@ func runSign(command *cobra.Command, cmdOpts *signOpts) error {
 	return nil
 }
 
-func prepareSigningContent(ctx context.Context, opts *signOpts, sigRepo notationregistry.Repository) (notation.SignOptions, registry.Reference, error) {
+func prepareSigningContent(ctx context.Context, opts *signOpts, sigRepo notationregistry.Repository) (notation.RemoteSignOptions, registry.Reference, error) {
 	ref, err := resolveReference(ctx, &opts.SecureFlagOpts, opts.reference, sigRepo, func(ref registry.Reference, manifestDesc ocispec.Descriptor) {
 		fmt.Fprintf(os.Stderr, "Warning: Always sign the artifact using digest(@sha256:...) rather than a tag(:%s) because tags are mutable and a tag reference can point to a different artifact than the one signed.\n", ref.Reference)
 	})
 	if err != nil {
-		return notation.SignOptions{}, registry.Reference{}, err
+		return notation.RemoteSignOptions{}, registry.Reference{}, err
 	}
 
 	mediaType, err := envelope.GetEnvelopeMediaType(opts.SignerFlagOpts.SignatureFormat)
 	if err != nil {
-		return notation.SignOptions{}, registry.Reference{}, err
+		return notation.RemoteSignOptions{}, registry.Reference{}, err
 	}
-	pluginConfig, err := cmd.ParseFlagPluginConfig(opts.pluginConfig)
+	pluginConfig, err := cmd.ParseFlagMap(opts.pluginConfig, cmd.PflagPluginConfig.Name)
 	if err != nil {
-		return notation.SignOptions{}, registry.Reference{}, err
+		return notation.RemoteSignOptions{}, registry.Reference{}, err
 	}
-
-	signOpts := notation.SignOptions{
-		ArtifactReference:  ref.String(),
-		SignatureMediaType: mediaType,
-		ExpiryDuration:     opts.expiry,
-		PluginConfig:       pluginConfig,
+	userMetadata, err := cmd.ParseFlagMap(opts.userMetadata, cmd.PflagUserMetadata.Name)
+	if err != nil {
+		return notation.RemoteSignOptions{}, registry.Reference{}, err
 	}
 
+	signOpts := notation.RemoteSignOptions{
+		SignOptions: notation.SignOptions{
+			ArtifactReference:  ref.String(),
+			SignatureMediaType: mediaType,
+			ExpiryDuration:     opts.expiry,
+			PluginConfig:       pluginConfig,
+		},
+		UserMetadata: userMetadata,
+	}
 	return signOpts, ref, nil
 }

cmd/notation/sign_test.go

@@ -100,7 +100,7 @@ func TestSignCommand_CorrectConfig(t *testing.T) {
 	if !reflect.DeepEqual(*expected, *opts) {
 		t.Fatalf("Expect sign opts: %v, got: %v", expected, opts)
 	}
-	config, err := cmd.ParseFlagPluginConfig(opts.pluginConfig)
+	config, err := cmd.ParseFlagMap(opts.pluginConfig, cmd.PflagPluginConfig.Name)
 	if err != nil {
 		t.Fatalf("Parse plugin Config flag failed: %v", err)
 	}

cmd/notation/verify.go

@@ -13,6 +13,7 @@ import (
 	"github.com/notaryproject/notation-go/verifier"
 	"github.com/notaryproject/notation-go/verifier/trustpolicy"
 	"github.com/notaryproject/notation/internal/cmd"
+	"github.com/notaryproject/notation/internal/ioutil"
 	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
 
 	"github.com/spf13/cobra"
@@ -24,6 +25,7 @@ type verifyOpts struct {
 	SecureFlagOpts
 	reference    string
 	pluginConfig []string
+	userMetadata []string
 }
 
 func verifyCommand(opts *verifyOpts) *cobra.Command {
@@ -57,6 +59,7 @@ Example - Verify a signature on an OCI artifact identified by a tag  (Notation w
 	opts.LoggingFlagOpts.ApplyFlags(command.Flags())
 	opts.SecureFlagOpts.ApplyFlags(command.Flags())
 	command.Flags().StringArrayVarP(&opts.pluginConfig, "plugin-config", "c", nil, "{key}={value} pairs that are passed as it is to a plugin, if the verification is associated with a verification plugin, refer plugin documentation to set appropriate values")
+	cmd.SetPflagUserMetadata(command.Flags(), &opts.userMetadata, cmd.PflagUserMetadataVerifyUsage)
 	return command
 }
 
@@ -86,7 +89,13 @@ func runVerify(command *cobra.Command, opts *verifyOpts) error {
 	}
 
 	// set up verification plugin config.
-	configs, err := cmd.ParseFlagPluginConfig(opts.pluginConfig)
+	configs, err := cmd.ParseFlagMap(opts.pluginConfig, cmd.PflagPluginConfig.Name)
+	if err != nil {
+		return err
+	}
+
+	// set up user metadata
+	userMetadata, err := cmd.ParseFlagMap(opts.userMetadata, cmd.PflagUserMetadata.Name)
 	if err != nil {
 		return err
 	}
@@ -97,14 +106,15 @@ func runVerify(command *cobra.Command, opts *verifyOpts) error {
 		// TODO: need to change MaxSignatureAttempts as a user input flag or
 		// a field in config.json
 		MaxSignatureAttempts: math.MaxInt64,
+		UserMetadata:         userMetadata,
 	}
 
 	// core verify process
 	_, outcomes, err := notation.Verify(ctx, verifier, sigRepo, verifyOpts)
 	// write out on failure
 	if err != nil || len(outcomes) == 0 {
 		if err != nil {
-			var errorVerificationFailed *notation.ErrorVerificationFailed
+			var errorVerificationFailed notation.ErrorVerificationFailed
 			if !errors.As(err, &errorVerificationFailed) {
 				return fmt.Errorf("signature verification failed: %w", err)
 			}
@@ -126,6 +136,7 @@ func runVerify(command *cobra.Command, opts *verifyOpts) error {
 		fmt.Println("Trust policy is configured to skip signature verification for", ref.String())
 	} else {
 		fmt.Println("Successfully verified signature for", ref.String())
+		printMetadataIfPresent(outcome)
 	}
 	return nil
 }
@@ -148,3 +159,15 @@ func resolveReference(ctx context.Context, opts *SecureFlagOpts, reference strin
 
 	return ref, nil
 }
+
+func printMetadataIfPresent(outcome *notation.VerificationOutcome) {
+	// the signature envelope is parsed as part of verification.
+	// since user metadata is only printed on successful verification,
+	// this error can be ignored
+	metadata, _ := outcome.UserMetadata()
+
+	if len(metadata) > 0 {
+		fmt.Println("\nThe artifact was signed with the following user metadata.")
+		ioutil.PrintMetadataMap(os.Stdout, metadata)
+	}
+}

go.mod

@@ -5,7 +5,7 @@ go 1.20
 require (
 	github.com/docker/docker-credential-helpers v0.7.0
 	github.com/notaryproject/notation-core-go v1.0.0-rc.1
-	github.com/notaryproject/notation-go v1.0.0-rc.1.0.20230203031935-510def1a3f48
+	github.com/notaryproject/notation-go v1.0.0-rc.1.0.20230208032042-6ef3544efa06
 	github.com/opencontainers/go-digest v1.0.0
 	github.com/opencontainers/image-spec v1.1.0-rc2
 	github.com/sirupsen/logrus v1.9.0

go.sum

@@ -22,6 +22,8 @@ github.com/notaryproject/notation-core-go v1.0.0-rc.1 h1:ACi0gr6mD1bzp9+gu3P0meJ
 github.com/notaryproject/notation-core-go v1.0.0-rc.1/go.mod h1:n8Gbvl9sKa00KptkKEL5XKUyMTIALe74QipKauE2rj4=
 github.com/notaryproject/notation-go v1.0.0-rc.1.0.20230203031935-510def1a3f48 h1:MHjaRqAn+uCBYkDuIGaVo91CnJY9MlTcZdYFfoE4yek=
 github.com/notaryproject/notation-go v1.0.0-rc.1.0.20230203031935-510def1a3f48/go.mod h1:B/26FcjJ9GVXm1j7z+/pWKck80LdFi3KiX4Zu7gixB8=
+github.com/notaryproject/notation-go v1.0.0-rc.1.0.20230208032042-6ef3544efa06 h1:0AuNQ3303yvINJSEzHUrLHSsJOyAEJvCGUit44GhERk=
+github.com/notaryproject/notation-go v1.0.0-rc.1.0.20230208032042-6ef3544efa06/go.mod h1:B/26FcjJ9GVXm1j7z+/pWKck80LdFi3KiX4Zu7gixB8=
 github.com/opencontainers/go-digest v1.0.0 h1:apOUWs51W5PlhuyGyz9FCeeBIOUDA/6nW8Oi/yOhh5U=
 github.com/opencontainers/go-digest v1.0.0/go.mod h1:0JzlMkj0TRzQZfJkVvzbP0HBR3IKzErnv2BNG4W4MAM=
 github.com/opencontainers/image-spec v1.1.0-rc2 h1:2zx/Stx4Wc5pIPDvIxHXvXtQFW/7XWJGmnM7r3wg034=

internal/cmd/flags.go

@@ -71,6 +71,16 @@ var (
 	SetPflagPluginConfig = func(fs *pflag.FlagSet, p *[]string) {
 		fs.StringArrayVarP(p, PflagPluginConfig.Name, PflagPluginConfig.Shorthand, nil, PflagPluginConfig.Usage)
 	}
+
+	PflagUserMetadata = &pflag.Flag{
+		Name:      "user-metadata",
+		Shorthand: "m",
+	}
+	PflagUserMetadataSignUsage = "{key}={value} pairs that are added to the signature payload"
+	PflagUserMetadataVerifyUsage = "user defined {key}={value} pairs that must be present in the signature for successful verification if provided"
+	SetPflagUserMetadata = func(fs *pflag.FlagSet, p *[]string, usage string) {
+		fs.StringArrayVarP(p, PflagUserMetadata.Name, PflagUserMetadata.Shorthand, nil, usage)
+	}
 )
 
 // KeyValueSlice is a flag with type int
@@ -79,14 +89,14 @@ type KeyValueSlice interface {
 	String() string
 }
 
-func ParseFlagPluginConfig(config []string) (map[string]string, error) {
-	pluginConfig := make(map[string]string, len(config))
-	for _, pair := range config {
+func ParseFlagMap(c []string, flagName string) (map[string]string, error) {
+	m := make(map[string]string, len(c))
+	for _, pair := range c {
 		key, val, found := strings.Cut(pair, "=")
 		if !found || key == "" || val == "" {
-			return nil, fmt.Errorf("could not parse flag %s: key-value pair requires \"=\" as separator", PflagPluginConfig.Name)
+			return nil, fmt.Errorf("could not parse flag %s: key-value pair requires \"=\" as separator", flagName)
 		}
-		pluginConfig[key] = val
+		m[key] = val
 	}
-	return pluginConfig, nil
+	return m, nil
 }

internal/ioutil/print.go

@@ -32,3 +32,14 @@ func PrintKeyMap(w io.Writer, target *string, v []config.KeySuite) error {
 	}
 	return tw.Flush()
 }
+
+func PrintMetadataMap(w io.Writer, metadata map[string]string) error {
+	tw := newTabWriter(w)
+	fmt.Fprintln(tw, "\nKEY\tVALUE\t")
+
+	for k, v := range metadata {
+		fmt.Fprintf(tw, "%v\t%v\t\n", k, v)
+	}
+
+	return tw.Flush()
+}