WIP: Expect UncompressedDigest to be set for partial pulls, enforce D…

…iffID match

Signed-off-by: Miloslav Trmač <[email protected]>

storage/storage_dest.go

@@ -370,23 +370,22 @@ func (s *storageImageDestination) PutBlobPartial(ctx context.Context, chunkAcces
 	if out.UncompressedDigest != "" {
 		s.lockProtected.indexToDiffID[options.LayerIndex] = out.UncompressedDigest
 		if out.TOCDigest != "" {
+			s.lockProtected.indexToTOCDigest[options.LayerIndex] = out.TOCDigest
 			options.Cache.RecordTOCUncompressedPair(out.TOCDigest, out.UncompressedDigest)
 		}
-		// Don’t set indexToTOCDigest on this path:
-		// - Using UncompressedDigest allows image reuse with non-partially-pulled layers, so we want to set indexToDiffID.
-		// - If UncompressedDigest has been computed, that means the layer was read completely, and the TOC has been created from scratch.
-		//   That TOC is quite unlikely to match any other TOC value.
 
-		// The computation of UncompressedDigest means the whole layer has been consumed; while doing that, chunked.GetDiffer is
+		// If the whole layer has been consumed, chunked.GetDiffer is
 		// responsible for ensuring blobDigest has been validated.
-		if out.CompressedDigest != blobDigest {
-			return private.UploadedBlob{}, fmt.Errorf("internal error: PrepareStagedLayer returned CompressedDigest %q not matching expected %q",
-				out.CompressedDigest, blobDigest)
-		}
-		// So, record also information about blobDigest, that might benefit reuse.
-		// We trust PrepareStagedLayer to validate or create both values correctly.
-		s.lockProtected.blobDiffIDs[blobDigest] = out.UncompressedDigest
-		options.Cache.RecordDigestUncompressedPair(out.CompressedDigest, out.UncompressedDigest)
+		if out.CompressedDigest != "" {
+			if out.CompressedDigest != blobDigest {
+				return private.UploadedBlob{}, fmt.Errorf("internal error: PrepareStagedLayer returned CompressedDigest %q not matching expected %q",
+					out.CompressedDigest, blobDigest)
+			}
+			// So, record also information about blobDigest, that might benefit reuse.
+			// We trust PrepareStagedLayer to validate or create both values correctly.
+			s.lockProtected.blobDiffIDs[blobDigest] = out.UncompressedDigest
+			options.Cache.RecordDigestUncompressedPair(out.CompressedDigest, out.UncompressedDigest)
+		}
 	} else {
 		// Use diffID for layer identity if it is known.
 		if uncompressedDigest := options.Cache.UncompressedDigestForTOC(out.TOCDigest); uncompressedDigest != "" {
@@ -936,12 +935,27 @@ func (s *storageImageDestination) createNewLayer(index int, layerDigest digest.D
 				return nil, nil
 			}
 
+			// FIXME: Should we insist on UncompressedDigest being always set, and hard fail otherwise??
 			untrustedUncompressedDigest = d
 			// While the contents of the digest are untrusted, make sure at least the _format_ is valid,
 			// because we are going to write it to durable storage in expectedLayerDiffIDFlag .
 			if err := untrustedUncompressedDigest.Validate(); err != nil {
 				return nil, err
 			}
+		} else {
+			// FIXME: Clean up. Maybe the generic code can provide us the config earlier?
+			// FIXME: Always enforce this for all layers??!
+			d, err := s.untrustedLayerDiffID(index)
+			if err != nil {
+				return nil, err
+			}
+			if d == "" {
+				logrus.Debugf("Skipping commit for layer %q, manifest not yet available", newLayerID)
+				return nil, nil
+			}
+			if diffOutput.UncompressedDigest != d {
+				return nil, fmt.Errorf("uncompressed digest inconsistency for layer %d: config %q vs. computed %q", index, d, diffOutput.UncompressedDigest)
+			}
 		}
 
 		flags := make(map[string]interface{})