Add registry endpoint to read and write image signatures

pkg/cmd/dockerregistry/dockerregistry.go

@@ -75,7 +75,6 @@ func Execute(configFile io.Reader) {
 
 	// TODO add https scheme
 	adminRouter := app.NewRoute().PathPrefix("/admin/").Subrouter()
-
 	pruneAccessRecords := func(*http.Request) []auth.Access {
 		return []auth.Access{
 			{
@@ -98,6 +97,16 @@ func Execute(configFile io.Reader) {
 		pruneAccessRecords,
 	)
 
+	// Registry extensions endpoint provides extra functionality to handle the image
+	// signatures.
+	server.RegisterSignatureHandler(app)
+
+	// Advertise features supported by OpenShift
+	if app.Config.HTTP.Headers == nil {
+		app.Config.HTTP.Headers = http.Header{}
+	}
+	app.Config.HTTP.Headers.Set("X-Registry-Supports-Signatures", "1")
+
 	app.RegisterHealthChecks()
 	handler := alive("/", app)
 	// TODO: temporarily keep for backwards compatibility; remove in the future

pkg/dockerregistry/server/auth.go

@@ -351,6 +351,22 @@ func (ac *AccessController) Authorized(ctx context.Context, accessRecords ...reg
 				}
 			}
 
+		case "signature":
+			namespace, name, err := getNamespaceName(access.Resource.Name)
+			if err != nil {
+				return nil, ac.wrapErr(ctx, err)
+			}
+			switch access.Action {
+			case "get":
+				if err := verifyImageStreamAccess(ctx, namespace, name, access.Action, osClient); err != nil {
+					return nil, ac.wrapErr(ctx, err)
+				}
+			case "put":
+				if err := verifyImageSignatureAccess(ctx, namespace, name, osClient); err != nil {
+					return nil, ac.wrapErr(ctx, err)
+				}
+			}
+
 		case "admin":
 			switch access.Action {
 			case "prune":
@@ -484,3 +500,27 @@ func verifyPruneAccess(ctx context.Context, client client.SubjectAccessReviews)
 	}
 	return nil
 }
+
+func verifyImageSignatureAccess(ctx context.Context, namespace, imageRepo string, client client.LocalSubjectAccessReviewsNamespacer) error {
+	sar := authorizationapi.LocalSubjectAccessReview{
+		Action: authorizationapi.Action{
+			Verb:         "create",
+			Group:        imageapi.GroupName,
+			Resource:     "imagesignatures",
+			ResourceName: imageRepo,
+		},
+	}
+	response, err := client.LocalSubjectAccessReviews(namespace).Create(&sar)
+	if err != nil {
+		context.GetLogger(ctx).Errorf("OpenShift client error: %s", err)
+		if kerrors.IsUnauthorized(err) || kerrors.IsForbidden(err) {
+			return ErrOpenShiftAccessDenied
+		}
+		return err
+	}
+	if !response.Allowed {
+		context.GetLogger(ctx).Errorf("OpenShift access denied: %s", response.Reason)
+		return ErrOpenShiftAccessDenied
+	}
+	return nil
+}

pkg/dockerregistry/server/signaturedispatcher.go

@@ -0,0 +1,193 @@
+package server
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+
+	kapierrors "k8s.io/kubernetes/pkg/api/errors"
+
+	ctxu "github.com/docker/distribution/context"
+
+	"github.com/docker/distribution/context"
+	"github.com/docker/distribution/registry/api/errcode"
+	"github.com/docker/distribution/registry/api/v2"
+	"github.com/docker/distribution/registry/handlers"
+
+	imageapi "github.com/openshift/origin/pkg/image/api"
+
+	gorillahandlers "github.com/gorilla/handlers"
+)
+
+const (
+	errGroup             = "registry.api.v2"
+	defaultSchemaVersion = 2
+)
+
+// signature represents a Docker image signature.
+type signature struct {
+	// Version specifies the schema version
+	Version int `json:"schemaVersion"`
+	// Name must be in "sha256:<digest>@signatureName" format
+	Name string `json:"name"`
+	// Type is optional, of not set it will be defaulted to "AtomicImageV1"
+	Type string `json:"type"`
+	// Content contains the signature
+	Content []byte `json:"content"`
+}
+
+// signatureList represents list of Docker image signatures.
+type signatureList struct {
+	Signatures []signature `json:"signatures"`
+}
+
+var (
+	ErrorCodeSignatureInvalid = errcode.Register(errGroup, errcode.ErrorDescriptor{
+		Value:          "SIGNATURE_INVALID",
+		Message:        "invalid image signature",
+		HTTPStatusCode: http.StatusBadRequest,
+	})
+
+	ErrorCodeSignatureAlreadyExists = errcode.Register(errGroup, errcode.ErrorDescriptor{
+		Value:          "SIGNATURE_EXISTS",
+		Message:        "image signature already exists",
+		HTTPStatusCode: http.StatusConflict,
+	})
+)
+
+type signatureHandler struct {
+	ctx       *handlers.Context
+	reference imageapi.DockerImageReference
+}
+
+// SignatureDispatcher handles the GET and PUT requests for signature endpoint.
+func SignatureDispatcher(ctx *handlers.Context, r *http.Request) http.Handler {
+	signatureHandler := &signatureHandler{ctx: ctx}
+	signatureHandler.reference, _ = imageapi.ParseDockerImageReference(ctxu.GetStringValue(ctx, "vars.name") + "@" + ctxu.GetStringValue(ctx, "vars.digest"))
+
+	return gorillahandlers.MethodHandler{
+		"GET": http.HandlerFunc(signatureHandler.Get),
+		"PUT": http.HandlerFunc(signatureHandler.Put),
+	}
+}
+
+func (s *signatureHandler) Put(w http.ResponseWriter, r *http.Request) {
+	context.GetLogger(s.ctx).Debugf("(*signatureHandler).Put")
+	if len(s.reference.String()) == 0 {
+		s.handleError(s.ctx, v2.ErrorCodeNameInvalid.WithDetail("missing image name or image ID"), w)
+		return
+	}
+
+	client, ok := UserClientFrom(s.ctx)
+	if !ok {
+		s.handleError(s.ctx, errcode.ErrorCodeUnknown.WithDetail("unable to get origin client"), w)
+		return
+	}
+
+	sig := signature{}
+	body, err := ioutil.ReadAll(r.Body)
+	if err != nil {
+		s.handleError(s.ctx, ErrorCodeSignatureInvalid.WithDetail(err.Error()), w)
+		return
+	}
+	if err := json.Unmarshal(body, &sig); err != nil {
+		s.handleError(s.ctx, ErrorCodeSignatureInvalid.WithDetail(err.Error()), w)
+		return
+	}
+
+	if len(sig.Type) == 0 {
+		sig.Type = imageapi.ImageSignatureTypeAtomicImageV1
+	}
+	if sig.Version != defaultSchemaVersion {
+		s.handleError(s.ctx, ErrorCodeSignatureInvalid.WithDetail(errors.New("only schemaVersion=2 is currently supported")), w)
+		return
+	}
+	newSig := &imageapi.ImageSignature{Content: sig.Content, Type: sig.Type}
+	newSig.Name = sig.Name
+
+	_, err = client.ImageSignatures().Create(newSig)
+	switch {
+	case err == nil:
+	case kapierrors.IsUnauthorized(err):
+		s.handleError(s.ctx, errcode.ErrorCodeUnauthorized.WithDetail(err.Error()), w)
+		return
+	case kapierrors.IsBadRequest(err):
+		s.handleError(s.ctx, ErrorCodeSignatureInvalid.WithDetail(err.Error()), w)
+		return
+	case kapierrors.IsNotFound(err):
+		w.WriteHeader(http.StatusNotFound)
+		return
+	case kapierrors.IsAlreadyExists(err):
+		s.handleError(s.ctx, ErrorCodeSignatureAlreadyExists.WithDetail(err.Error()), w)
+		return
+	default:
+		s.handleError(s.ctx, errcode.ErrorCodeUnknown.WithDetail(fmt.Sprintf("unable to create image %s signature: %v", s.reference.String(), err)), w)
+		return
+	}
+
+	// Return just 201 with no body.
+	// TODO: The docker registry actually returns the Location header
+	w.WriteHeader(http.StatusCreated)
+	context.GetLogger(s.ctx).Debugf("(*signatureHandler).Put signature successfully added to %s", s.reference.String())
+}
+
+func (s *signatureHandler) Get(w http.ResponseWriter, req *http.Request) {
+	context.GetLogger(s.ctx).Debugf("(*signatureHandler).Get")
+	w.Header().Set("Content-Type", "application/json; charset=utf-8")
+	if len(s.reference.String()) == 0 {
+		s.handleError(s.ctx, v2.ErrorCodeNameInvalid.WithDetail("missing image name or image ID"), w)
+		return
+	}
+	client, ok := UserClientFrom(s.ctx)
+	if !ok {
+		s.handleError(s.ctx, errcode.ErrorCodeUnknown.WithDetail("unable to get origin client"), w)
+		return
+	}
+
+	if len(s.reference.ID) == 0 {
+		s.handleError(s.ctx, v2.ErrorCodeNameInvalid.WithDetail("the image ID must be specified (sha256:<digest>"), w)
+		return
+	}
+
+	image, err := client.ImageStreamImages(s.reference.Namespace).Get(s.reference.Name, s.reference.ID)
+	switch {
+	case err == nil:
+	case kapierrors.IsUnauthorized(err):
+		s.handleError(s.ctx, errcode.ErrorCodeUnauthorized.WithDetail(fmt.Sprintf("not authorized to get image %q signature: %v", s.reference.String(), err)), w)
+		return
+	case kapierrors.IsNotFound(err):
+		w.WriteHeader(http.StatusNotFound)
+		return
+	default:
+		s.handleError(s.ctx, errcode.ErrorCodeUnknown.WithDetail(fmt.Sprintf("unable to get image %q signature: %v", s.reference.String(), err)), w)
+		return
+	}
+
+	// Transform the OpenShift ImageSignature into Registry signature object.
+	signatures := signatureList{Signatures: []signature{}}
+	for _, s := range image.Image.Signatures {
+		signatures.Signatures = append(signatures.Signatures, signature{
+			Version: defaultSchemaVersion,
+			Name:    s.Name,
+			Type:    s.Type,
+			Content: s.Content,
+		})
+	}
+
+	if data, err := json.Marshal(signatures); err != nil {
+		s.handleError(s.ctx, errcode.ErrorCodeUnknown.WithDetail(fmt.Sprintf("failed to serialize image signature %v", err)), w)
+	} else {
+		w.Write(data)
+	}
+}
+
+func (s *signatureHandler) handleError(ctx context.Context, err error, w http.ResponseWriter) {
+	context.GetLogger(ctx).Errorf("(*signatureHandler): %v", err)
+	ctx, w = context.WithResponseWriter(ctx, w)
+	if serveErr := errcode.ServeJSON(w, err); serveErr != nil {
+		context.GetResponseLogger(ctx).Errorf("error sending error response: %v", serveErr)
+		return
+	}
+}