@@ -482,6 +482,10 @@ func (s *TagStore) pullV2Repository(r *registry.Session, out io.Writer, repoInfo

 	if err != nil {

 		return fmt.Errorf("error getting authorization: %s", err)

 	}

+	if !auth.CanAuthorizeV2() {

+		return ErrV2RegistryUnavailable

+	}

+

 	var layersDownloaded bool

 	if tag == "" {

 		logrus.Debugf("Pulling tag list from V2 registry for %s", repoInfo.CanonicalName)

@@ -322,6 +322,9 @@ func (s *TagStore) pushV2Repository(r *registry.Session, localRepo Repository, o

 	if err != nil {

 		return fmt.Errorf("error getting authorization: %s", err)

 	}

+	if !auth.CanAuthorizeV2() {

+		return ErrV2RegistryUnavailable

+	}

 	for _, tag := range tags {

 		logrus.Debugf("Pushing repository: %s:%s", repoInfo.CanonicalName, tag)

@@ -549,6 +552,7 @@ func (s *TagStore) Push(localName string, imagePushConfig *ImagePushConfig) erro

 		if err != ErrV2RegistryUnavailable {

 			return fmt.Errorf("Error pushing to registry: %s", err)

 		}

+		logrus.Debug("V2 registry is unavailable, falling back on V1")

 	}

 	if err := s.pushRepository(r, imagePushConfig.OutStream, repoInfo, localRepo, imagePushConfig.Tag, sf); err != nil {

@@ -74,6 +74,19 @@ func (auth *RequestAuthorization) getToken() (string, error) {

 	return "", nil

 }

+// Checks that requests to the v2 registry can be authorized.

+func (auth *RequestAuthorization) CanAuthorizeV2() bool {

+	if len(auth.registryEndpoint.AuthChallenges) == 0 {

+		return true

+	}

+	scope := fmt.Sprintf("%s:%s:%s", auth.resource, auth.scope, strings.Join(auth.actions, ","))

+	if _, err := loginV2(auth.authConfig, auth.registryEndpoint, scope); err != nil {

+		logrus.Debugf("Cannot authorize against V2 endpoint: %s", auth.registryEndpoint)

+		return false

+	}

+	return true

+}

+

 func (auth *RequestAuthorization) Authorize(req *http.Request) error {

 	token, err := auth.getToken()

 	if err != nil {

@@ -91,7 +104,7 @@ func (auth *RequestAuthorization) Authorize(req *http.Request) error {

 func Login(authConfig *cliconfig.AuthConfig, registryEndpoint *Endpoint) (string, error) {

 	// Separates the v2 registry login logic from the v1 logic.

 	if registryEndpoint.Version == APIVersion2 {

-		return loginV2(authConfig, registryEndpoint)

+		return loginV2(authConfig, registryEndpoint, "" /* scope */)

 	}

 	return loginV1(authConfig, registryEndpoint)

 }

@@ -209,7 +222,7 @@ func loginV1(authConfig *cliconfig.AuthConfig, registryEndpoint *Endpoint) (stri

 // now, users should create their account through other means like directly from a web page

 // served by the v2 registry service provider. Whether this will be supported in the future

 // is to be determined.

-func loginV2(authConfig *cliconfig.AuthConfig, registryEndpoint *Endpoint) (string, error) {

+func loginV2(authConfig *cliconfig.AuthConfig, registryEndpoint *Endpoint, scope string) (string, error) {

 	logrus.Debugf("attempting v2 login to registry endpoint %s", registryEndpoint)

 	var (

 		err       error

@@ -217,13 +230,18 @@ func loginV2(authConfig *cliconfig.AuthConfig, registryEndpoint *Endpoint) (stri

 	)

 	for _, challenge := range registryEndpoint.AuthChallenges {

-		logrus.Debugf("trying %q auth challenge with params %s", challenge.Scheme, challenge.Parameters)

+		params := make(map[string]string, len(challenge.Parameters)+1)

+		for k, v := range challenge.Parameters {

+			params[k] = v

+		}

+		params["scope"] = scope

+		logrus.Debugf("trying %q auth challenge with params %v", challenge.Scheme, params)

 		switch strings.ToLower(challenge.Scheme) {

 		case "basic":

-			err = tryV2BasicAuthLogin(authConfig, challenge.Parameters, registryEndpoint)

+			err = tryV2BasicAuthLogin(authConfig, params, registryEndpoint)

 		case "bearer":

-			err = tryV2TokenAuthLogin(authConfig, challenge.Parameters, registryEndpoint)

+			err = tryV2TokenAuthLogin(authConfig, params, registryEndpoint)

 		default:

 			// Unsupported challenge types are explicitly skipped.

 			err = fmt.Errorf("unsupported auth scheme: %q", challenge.Scheme)