update c/buildah to v1.12.0

Also bump docker/docker.

Signed-off-by: Valentin Rothberg <rothberg@redhat.com>

vendor/github.com/containers/buildah/imagebuildah/stage_executor.go

@@ -423,38 +423,43 @@ func (s *StageExecutor) Copy(excludes []string, copies ...imagebuilder.Copy) err
 		}
 		for _, src := range copy.Src {
 			if strings.HasPrefix(src, "http://") || strings.HasPrefix(src, "https://") {
-				// Source is a URL.
-				// returns an error to be compatible with docker
-				return errors.Errorf("source can't be a URL for COPY")
-			}
-			// Treat the source, which is not a URL, as a
-			// location relative to the
-			// all-content-comes-from-below-this-directory
-			// directory.
-			srcSecure, err := securejoin.SecureJoin(contextDir, src)
-			if err != nil {
-				return errors.Wrapf(err, "forbidden path for %q, it is outside of the build context %q", src, contextDir)
-			}
-			if hadFinalPathSeparator {
-				// If destination is a folder, we need to take extra care to
-				// ensure that files are copied with correct names (since
-				// resolving a symlink may result in a different name).
-				_, srcName := filepath.Split(src)
-				_, srcNameSecure := filepath.Split(srcSecure)
-				if srcName != srcNameSecure {
-					options := buildah.AddAndCopyOptions{
-						Chown:            copy.Chown,
-						ContextDir:       contextDir,
-						Excludes:         copyExcludes,
-						IDMappingOptions: idMappingOptions,
-					}
-					if err := s.builder.Add(filepath.Join(copy.Dest, srcName), copy.Download, options, srcSecure); err != nil {
-						return err
-					}
-					continue
+				// Source is a URL, allowed for ADD but not COPY.
+				if copy.Download {
+					sources = append(sources, src)
+				} else {
+					// returns an error to be compatible with docker
+					return errors.Errorf("source can't be a URL for COPY")
 				}
+			} else {
+				// Treat the source, which is not a URL, as a
+				// location relative to the
+				// all-content-comes-from-below-this-directory
+				// directory.
+				srcSecure, err := securejoin.SecureJoin(contextDir, src)
+				if err != nil {
+					return errors.Wrapf(err, "forbidden path for %q, it is outside of the build context %q", src, contextDir)
+				}
+				if hadFinalPathSeparator {
+					// If destination is a folder, we need to take extra care to
+					// ensure that files are copied with correct names (since
+					// resolving a symlink may result in a different name).
+					_, srcName := filepath.Split(src)
+					_, srcNameSecure := filepath.Split(srcSecure)
+					if srcName != srcNameSecure {
+						options := buildah.AddAndCopyOptions{
+							Chown:            copy.Chown,
+							ContextDir:       contextDir,
+							Excludes:         copyExcludes,
+							IDMappingOptions: idMappingOptions,
+						}
+						if err := s.builder.Add(filepath.Join(copy.Dest, srcName), copy.Download, options, srcSecure); err != nil {
+							return err
+						}
+						continue
+					}
+				}
+				sources = append(sources, srcSecure)
 			}
-			sources = append(sources, srcSecure)
 		}
 		options := buildah.AddAndCopyOptions{
 			Chown:            copy.Chown,