Avoid manifest verification errors by using Raw

Because json.Marshal does compaction on returned results, applications must
directly use SignedManifest.Raw when the marshaled value is required.
Otherwise, the returned manifest will fail signature checks.

api_test.go

@@ -277,7 +277,7 @@ func TestManifestAPI(t *testing.T) {
 
 	resp = putManifest(t, "putting signed manifest", manifestURL, signedManifest)
 
-	checkResponse(t, "putting manifest", resp, http.StatusOK)
+	checkResponse(t, "putting signed manifest", resp, http.StatusOK)
 
 	resp, err = http.Get(manifestURL)
 	if err != nil {
@@ -299,9 +299,15 @@ func TestManifestAPI(t *testing.T) {
 }
 
 func putManifest(t *testing.T, msg, url string, v interface{}) *http.Response {
-	body, err := json.Marshal(v)
-	if err != nil {
-		t.Fatalf("unexpected error marshaling %v: %v", v, err)
+	var body []byte
+	if sm, ok := v.(*storage.SignedManifest); ok {
+		body = sm.Raw
+	} else {
+		var err error
+		body, err = json.MarshalIndent(v, "", "   ")
+		if err != nil {
+			t.Fatalf("unexpected error marshaling %v: %v", v, err)
+		}
 	}
 
 	req, err := http.NewRequest("PUT", url, bytes.NewReader(body))

storage/manifest.go

@@ -140,8 +140,9 @@ type SignedManifest struct {
 	Manifest
 
 	// Raw is the byte representation of the ImageManifest, used for signature
-	// verification. The manifest byte representation cannot change or it will
-	// have to be re-signed.
+	// 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:"-"`
 }
 
@@ -184,7 +185,9 @@ func (sm *SignedManifest) UnmarshalJSON(b []byte) error {
 }
 
 // MarshalJSON returns the contents of raw. If Raw is nil, marshals the inner
-// contents.
+// contents. Applications requiring a marshaled signed manifest should simply
+// use Raw directly, since the the content produced by json.Marshal will
+// compacted and will fail signature checks.
 func (sm *SignedManifest) MarshalJSON() ([]byte, error) {
 	if len(sm.Raw) > 0 {
 		return sm.Raw, nil