distribution/manifest/schema1/manifest.go
Stephen J Day 76624704c3 Correct unmarshal order for SignedManifest
To ensure that we only unmarshal the verified payload into the contained
manifest, we first copy the entire incoming buffer into Raw and then unmarshal
only the Payload portion of the incoming bytes. If the contents is later
verified, the caller can then be sure that the contents of the Manifest fields
can be trusted.

Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
2015-10-14 14:37:34 -07:00

130 lines
3.7 KiB
Go

package schema1
import (
"encoding/json"
"github.com/docker/distribution/digest"
"github.com/docker/distribution/manifest"
"github.com/docker/libtrust"
)
// TODO(stevvooe): When we rev the manifest format, the contents of this
// package should be moved to manifest/v1.
const (
// ManifestMediaType specifies the mediaType for the current version. Note
// that for schema version 1, the the media is optionally
// "application/json".
ManifestMediaType = "application/vnd.docker.distribution.manifest.v1+json"
)
var (
// SchemaVersion provides a pre-initialized version structure for this
// packages version of the manifest.
SchemaVersion = manifest.Versioned{
SchemaVersion: 1,
}
)
// Manifest provides the base accessible fields for working with V2 image
// format in the registry.
type Manifest struct {
manifest.Versioned
// Name is the name of the image's repository
Name string `json:"name"`
// Tag is the tag of the image specified by this manifest
Tag string `json:"tag"`
// Architecture is the host architecture on which this image is intended to
// run
Architecture string `json:"architecture"`
// FSLayers is a list of filesystem layer blobSums contained in this image
FSLayers []FSLayer `json:"fsLayers"`
// History is a list of unstructured historical data for v1 compatibility
History []History `json:"history"`
}
// SignedManifest provides an envelope for a signed image manifest, including
// the format sensitive raw bytes. It contains fields to
type SignedManifest struct {
Manifest
// Raw is the byte representation of the ImageManifest, used for signature
// verification. The value of Raw must be used directly during
// serialization, or the signature check will fail. The manifest byte
// representation cannot change or it will have to be re-signed.
Raw []byte `json:"-"`
}
// UnmarshalJSON populates a new ImageManifest struct from JSON data.
func (sm *SignedManifest) UnmarshalJSON(b []byte) error {
sm.Raw = make([]byte, len(b), len(b))
copy(sm.Raw, b)
p, err := sm.Payload()
if err != nil {
return err
}
var manifest Manifest
if err := json.Unmarshal(p, &manifest); err != nil {
return err
}
sm.Manifest = manifest
return nil
}
// Payload returns the raw, signed content of the signed manifest. The
// contents can be used to calculate the content identifier.
func (sm *SignedManifest) Payload() ([]byte, error) {
jsig, err := libtrust.ParsePrettySignature(sm.Raw, "signatures")
if err != nil {
return nil, err
}
// Resolve the payload in the manifest.
return jsig.Payload()
}
// Signatures returns the signatures as provided by
// (*libtrust.JSONSignature).Signatures. The byte slices are opaque jws
// signatures.
func (sm *SignedManifest) Signatures() ([][]byte, error) {
jsig, err := libtrust.ParsePrettySignature(sm.Raw, "signatures")
if err != nil {
return nil, err
}
// Resolve the payload in the manifest.
return jsig.Signatures()
}
// MarshalJSON returns the contents of raw. If Raw is nil, marshals the inner
// contents. Applications requiring a marshaled signed manifest should simply
// use Raw directly, since the the content produced by json.Marshal will be
// compacted and will fail signature checks.
func (sm *SignedManifest) MarshalJSON() ([]byte, error) {
if len(sm.Raw) > 0 {
return sm.Raw, nil
}
// If the raw data is not available, just dump the inner content.
return json.Marshal(&sm.Manifest)
}
// FSLayer is a container struct for BlobSums defined in an image manifest
type FSLayer struct {
// BlobSum is the tarsum of the referenced filesystem image layer
BlobSum digest.Digest `json:"blobSum"`
}
// History stores unstructured v1 compatibility information
type History struct {
// V1Compatibility is the raw v1 compatibility information
V1Compatibility string `json:"v1Compatibility"`
}