3 files changed, 39 insertions, 3 deletions
diff --git a/modules/packages/container/const.go b/modules/packages/container/const.go
new file mode 100644
index 0000000000..6c7c9b46d1
--- /dev/null
+++ b/modules/packages/container/const.go
@@ -0,0 +1,11 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package container
+
+const (
+	ContentTypeDockerDistributionManifestV2 = "application/vnd.docker.distribution.manifest.v2+json"
+
+	ManifestFilename = "manifest.json"
+	UploadVersion    = "_upload"
+)
diff --git a/modules/packages/container/metadata.go b/modules/packages/container/metadata.go
index 2a41fb9105..3ef0684d13 100644
--- a/modules/packages/container/metadata.go
+++ b/modules/packages/container/metadata.go
@@ -71,14 +71,34 @@ type Manifest struct {
 	Size     int64  `json:"size"`
 }
 
+func IsMediaTypeValid(mt string) bool {
+	return strings.HasPrefix(mt, "application/vnd.docker.") || strings.HasPrefix(mt, "application/vnd.oci.")
+}
+
+func IsMediaTypeImageManifest(mt string) bool {
+	return strings.EqualFold(mt, oci.MediaTypeImageManifest) || strings.EqualFold(mt, "application/vnd.docker.distribution.manifest.v2+json")
+}
+
+func IsMediaTypeImageIndex(mt string) bool {
+	return strings.EqualFold(mt, oci.MediaTypeImageIndex) || strings.EqualFold(mt, "application/vnd.docker.distribution.manifest.list.v2+json")
+}
+
 // ParseImageConfig parses the metadata of an image config
-func ParseImageConfig(mt string, r io.Reader) (*Metadata, error) {
-	if strings.EqualFold(mt, helm.ConfigMediaType) {
+func ParseImageConfig(mediaType string, r io.Reader) (*Metadata, error) {
+	if strings.EqualFold(mediaType, helm.ConfigMediaType) {
 		return parseHelmConfig(r)
 	}
 
 	// fallback to OCI Image Config
-	return parseOCIImageConfig(r)
+	// FIXME: this fallback is not right, we should strictly check the media type in the future
+	metadata, err := parseOCIImageConfig(r)
+	if err != nil {
+		if !IsMediaTypeImageManifest(mediaType) {
+			return &Metadata{Platform: "unknown/unknown"}, nil
+		}
+		return nil, err
+	}
+	return metadata, nil
 }
 
 func parseOCIImageConfig(r io.Reader) (*Metadata, error) {
diff --git a/modules/packages/container/metadata_test.go b/modules/packages/container/metadata_test.go
index 665499b2e6..0f2d702925 100644
--- a/modules/packages/container/metadata_test.go
+++ b/modules/packages/container/metadata_test.go
@@ -11,6 +11,7 @@ import (
 
 	oci "github.com/opencontainers/image-spec/specs-go/v1"
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 func TestParseImageConfig(t *testing.T) {
@@ -58,4 +59,8 @@ func TestParseImageConfig(t *testing.T) {
 	assert.ElementsMatch(t, []string{author}, metadata.Authors)
 	assert.Equal(t, projectURL, metadata.ProjectURL)
 	assert.Equal(t, repositoryURL, metadata.RepositoryURL)
+
+	metadata, err = ParseImageConfig("anything-unknown", strings.NewReader(""))
+	require.NoError(t, err)
+	assert.Equal(t, &Metadata{Platform: "unknown/unknown"}, metadata)
 }