api: server: check for unauthorized error

This functionality has been fixed by
7bca932182 but then it has been broken
again by a793564b25 and finally refixed
here.

Basically the functionality was to prompt for login when trying to pull
from the official docker hub.

Signed-off-by: Antonio Murdaca <runcom@redhat.com>
(cherry picked from commit 4316ae2ed3)

api/server/httputils/errors.go

@@ -52,6 +52,7 @@ func WriteError(w http.ResponseWriter, err error) {
 			"conflict":              http.StatusConflict,
 			"impossible":            http.StatusNotAcceptable,
 			"wrong login/password":  http.StatusUnauthorized,
+			"unauthorized":          http.StatusUnauthorized,
 			"hasn't been activated": http.StatusForbidden,
 		} {
 			if strings.Contains(errStr, keyword) {

api/server/router/image/image_routes.go

@@ -7,11 +7,9 @@ import (
 	"fmt"
 	"io"
 	"net/http"
-	"net/url"
 	"strings"
 
 	"github.com/docker/distribution/digest"
-	"github.com/docker/distribution/registry/api/errcode"
 	"github.com/docker/docker/api/server/httputils"
 	"github.com/docker/docker/builder/dockerfile"
 	"github.com/docker/docker/pkg/ioutils"
@@ -132,12 +130,6 @@ func (s *imageRouter) postImagesCreate(ctx context.Context, w http.ResponseWrite
 				err = s.backend.PullImage(ctx, ref, metaHeaders, authConfig, output)
 			}
 		}
-		// Check the error from pulling an image to make sure the request
-		// was authorized. Modify the status if the request was
-		// unauthorized to respond with 401 rather than 500.
-		if err != nil && isAuthorizedError(err) {
-			err = errcode.ErrorCodeUnauthorized.WithMessage(fmt.Sprintf("Authentication is required: %s", err))
-		}
 	} else { //import
 		var newRef reference.Named
 		if repo != "" {
@@ -389,16 +381,3 @@ func (s *imageRouter) getImagesSearch(ctx context.Context, w http.ResponseWriter
 	}
 	return httputils.WriteJSON(w, http.StatusOK, query.Results)
 }
-
-func isAuthorizedError(err error) bool {
-	if urlError, ok := err.(*url.Error); ok {
-		err = urlError.Err
-	}
-
-	if dError, ok := err.(errcode.Error); ok {
-		if dError.ErrorCode() == errcode.ErrorCodeUnauthorized {
-			return true
-		}
-	}
-	return false
-}