// validateBlob checks the data against the digest, returning an error if it
// does not match. The canonical descriptor is returned.
func (bw *blobWriter) validateBlob(ctx context.Context, desc distribution.Descriptor) (distribution.Descriptor, error) {
var (
verified, fullHash bool
canonical digest.Digest
)
if desc.Digest == "" {
// if no descriptors are provided, we have nothing to validate
// against. We don't really want to support this for the registry.
return distribution.Descriptor{}, distribution.ErrBlobInvalidDigest{
Reason: fmt.Errorf("cannot validate against empty digest"),
}
}
// Stat the on disk file
if fi, err := bw.bufferedFileWriter.driver.Stat(ctx, bw.path); err != nil {
switch err := err.(type) {
case storagedriver.PathNotFoundError:
// NOTE(stevvooe): We really don't care if the file is
// not actually present for the reader. We now assume
// that the desc length is zero.
desc.Size = 0
default:
// Any other error we want propagated up the stack.
return distribution.Descriptor{}, err
}
} else {
if fi.IsDir() {
return distribution.Descriptor{}, fmt.Errorf("unexpected directory at upload location %q", bw.path)
}
bw.size = fi.Size()
}
if desc.Size > 0 {
if desc.Size != bw.size {
return distribution.Descriptor{}, distribution.ErrBlobInvalidLength
}
} else {
// if provided 0 or negative length, we can assume caller doesn't know or
// care about length.
desc.Size = bw.size
}
// TODO(stevvooe): This section is very meandering. Need to be broken down
// to be a lot more clear.
if err := bw.resumeDigestAt(ctx, bw.size); err == nil {
canonical = bw.digester.Digest()
if canonical.Algorithm() == desc.Digest.Algorithm() {
// Common case: client and server prefer the same canonical digest
// algorithm - currently SHA256.
verified = desc.Digest == canonical
} else {
// The client wants to use a different digest algorithm. They'll just
// have to be patient and wait for us to download and re-hash the
// uploaded content using that digest algorithm.
fullHash = true
}
} else if err == errResumableDigestNotAvailable {
// Not using resumable digests, so we need to hash the entire layer.
fullHash = true
} else {
return distribution.Descriptor{}, err
}
if fullHash {
// a fantastic optimization: if the the written data and the size are
// the same, we don't need to read the data from the backend. This is
// because we've written the entire file in the lifecycle of the
// current instance.
if bw.written == bw.size && digest.Canonical == desc.Digest.Algorithm() {
canonical = bw.digester.Digest()
verified = desc.Digest == canonical
}
// If the check based on size fails, we fall back to the slowest of
// paths. We may be able to make the size-based check a stronger
// guarantee, so this may be defensive.
if !verified {
digester := digest.Canonical.New()
digestVerifier, err := digest.NewDigestVerifier(desc.Digest)
if err != nil {
return distribution.Descriptor{}, err
}
// Read the file from the backend driver and validate it.
fr, err := newFileReader(ctx, bw.bufferedFileWriter.driver, bw.path, desc.Size)
if err != nil {
return distribution.Descriptor{}, err
}
tr := io.TeeReader(fr, digester.Hash())
if _, err := io.Copy(digestVerifier, tr); err != nil {
return distribution.Descriptor{}, err
}
canonical = digester.Digest()
verified = digestVerifier.Verified()
}
}
if !verified {
context.GetLoggerWithFields(ctx,
map[string]interface{}{
"canonical": canonical,
"provided": desc.Digest,
}, "canonical", "provided").
Errorf("canonical digest does match provided digest")
return distribution.Descriptor{}, distribution.ErrBlobInvalidDigest{
Digest: desc.Digest,
Reason: fmt.Errorf("content does not match digest"),
}
}
// update desc with canonical hash
desc.Digest = canonical
if desc.MediaType == "" {
desc.MediaType = "application/octet-stream"
}
return desc, nil
}
func checkBlobDescriptorCacheSetAndRead(t *testing.T, ctx context.Context, provider BlobDescriptorCacheProvider) {
localDigest := digest.Digest("sha384:abc")
expected := distribution.Descriptor{
Digest: "sha256:abc",
Size: 10,
MediaType: "application/octet-stream"}
cache, err := provider.RepositoryScoped("foo/bar")
if err != nil {
t.Fatalf("unexpected error getting scoped cache: %v", err)
}
if err := cache.SetDescriptor(ctx, localDigest, expected); err != nil {
t.Fatalf("error setting descriptor: %v", err)
}
desc, err := cache.Stat(ctx, localDigest)
if err != nil {
t.Fatalf("unexpected error statting fake2:abc: %v", err)
}
if expected != desc {
t.Fatalf("unexpected descriptor: %#v != %#v", expected, desc)
}
// also check that we set the canonical key ("fake:abc")
desc, err = cache.Stat(ctx, localDigest)
if err != nil {
t.Fatalf("descriptor not returned for canonical key: %v", err)
}
if expected != desc {
t.Fatalf("unexpected descriptor: %#v != %#v", expected, desc)
}
// ensure that global gets extra descriptor mapping
desc, err = provider.Stat(ctx, localDigest)
if err != nil {
t.Fatalf("expected blob unknown in global cache: %v, %v", err, desc)
}
if desc != expected {
t.Fatalf("unexpected descriptor: %#v != %#v", expected, desc)
}
// get at it through canonical descriptor
desc, err = provider.Stat(ctx, expected.Digest)
if err != nil {
t.Fatalf("unexpected error checking glboal descriptor: %v", err)
}
if desc != expected {
t.Fatalf("unexpected descriptor: %#v != %#v", expected, desc)
}
// now, we set the repo local mediatype to something else and ensure it
// doesn't get changed in the provider cache.
expected.MediaType = "application/json"
if err := cache.SetDescriptor(ctx, localDigest, expected); err != nil {
t.Fatalf("unexpected error setting descriptor: %v", err)
}
desc, err = cache.Stat(ctx, localDigest)
if err != nil {
t.Fatalf("unexpected error getting descriptor: %v", err)
}
if desc != expected {
t.Fatalf("unexpected descriptor: %#v != %#v", desc, expected)
}
desc, err = provider.Stat(ctx, localDigest)
if err != nil {
t.Fatalf("unexpected error getting global descriptor: %v", err)
}
expected.MediaType = "application/octet-stream" // expect original mediatype in global
if desc != expected {
t.Fatalf("unexpected descriptor: %#v != %#v", desc, expected)
}
}