package graph import ( "errors" "fmt" "io" "io/ioutil" "os" "github.com/Sirupsen/logrus" "github.com/docker/distribution" "github.com/docker/distribution/digest" "github.com/docker/distribution/manifest" "github.com/docker/docker/image" "github.com/docker/docker/pkg/progressreader" "github.com/docker/docker/pkg/streamformatter" "github.com/docker/docker/pkg/stringid" "github.com/docker/docker/registry" "github.com/docker/docker/trust" "github.com/docker/docker/utils" "github.com/docker/libtrust" "golang.org/x/net/context" ) type v2Puller struct { *TagStore endpoint registry.APIEndpoint config *ImagePullConfig sf *streamformatter.StreamFormatter repoInfo *registry.RepositoryInfo repo distribution.Repository sessionID string } func (p *v2Puller) Pull(tag string) (fallback bool, err error) { // TODO(tiborvass): was ReceiveTimeout p.repo, err = NewV2Repository(p.repoInfo, p.endpoint, p.config.MetaHeaders, p.config.AuthConfig) if err != nil { logrus.Debugf("Error getting v2 registry: %v", err) return true, err } p.sessionID = stringid.GenerateRandomID() if err := p.pullV2Repository(tag); err != nil { if registry.ContinueOnError(err) { logrus.Debugf("Error trying v2 registry: %v", err) return true, err } return false, err } return false, nil } func (p *v2Puller) pullV2Repository(tag string) (err error) { var tags []string taggedName := p.repoInfo.LocalName if len(tag) > 0 { tags = []string{tag} taggedName = utils.ImageReference(p.repoInfo.LocalName, tag) } else { var err error manSvc, err := p.repo.Manifests(context.Background()) if err != nil { return err } tags, err = manSvc.Tags() if err != nil { return err } } c, err := p.poolAdd("pull", taggedName) if err != nil { if c != nil { // Another pull of the same repository is already taking place; just wait for it to finish p.sf.FormatStatus("", "Repository %s already being pulled by another client. Waiting.", p.repoInfo.CanonicalName) <-c return nil } return err } defer p.poolRemove("pull", taggedName) var layersDownloaded bool for _, tag := range tags { // pulledNew is true if either new layers were downloaded OR if existing images were newly tagged // TODO(tiborvass): should we change the name of `layersDownload`? What about message in WriteStatus? pulledNew, err := p.pullV2Tag(tag, taggedName) if err != nil { return err } layersDownloaded = layersDownloaded || pulledNew } writeStatus(taggedName, p.config.OutStream, p.sf, layersDownloaded) return nil } // downloadInfo is used to pass information from download to extractor type downloadInfo struct { img *image.Image tmpFile *os.File digest digest.Digest layer distribution.ReadSeekCloser size int64 err chan error out io.Writer // Download progress is written here. } type errVerification struct{} func (errVerification) Error() string { return "verification failed" } func (p *v2Puller) download(di *downloadInfo) { logrus.Debugf("pulling blob %q to %s", di.digest, di.img.ID) out := di.out if c, err := p.poolAdd("pull", "img:"+di.img.ID); err != nil { if c != nil { out.Write(p.sf.FormatProgress(stringid.TruncateID(di.img.ID), "Layer already being pulled by another client. Waiting.", nil)) <-c out.Write(p.sf.FormatProgress(stringid.TruncateID(di.img.ID), "Download complete", nil)) } else { logrus.Debugf("Image (id: %s) pull is already running, skipping: %v", di.img.ID, err) } di.err <- nil return } defer p.poolRemove("pull", "img:"+di.img.ID) tmpFile, err := ioutil.TempFile("", "GetImageBlob") if err != nil { di.err <- err return } blobs := p.repo.Blobs(nil) desc, err := blobs.Stat(nil, di.digest) if err != nil { logrus.Debugf("Error statting layer: %v", err) di.err <- err return } di.size = desc.Size layerDownload, err := blobs.Open(nil, di.digest) if err != nil { logrus.Debugf("Error fetching layer: %v", err) di.err <- err return } defer layerDownload.Close() verifier, err := digest.NewDigestVerifier(di.digest) if err != nil { di.err <- err return } reader := progressreader.New(progressreader.Config{ In: ioutil.NopCloser(io.TeeReader(layerDownload, verifier)), Out: out, Formatter: p.sf, Size: di.size, NewLines: false, ID: stringid.TruncateID(di.img.ID), Action: "Downloading", }) io.Copy(tmpFile, reader) out.Write(p.sf.FormatProgress(stringid.TruncateID(di.img.ID), "Verifying Checksum", nil)) if !verifier.Verified() { err = fmt.Errorf("filesystem layer verification failed for digest %s", di.digest) logrus.Error(err) di.err <- err return } out.Write(p.sf.FormatProgress(stringid.TruncateID(di.img.ID), "Download complete", nil)) logrus.Debugf("Downloaded %s to tempfile %s", di.img.ID, tmpFile.Name()) di.tmpFile = tmpFile di.layer = layerDownload di.err <- nil } func (p *v2Puller) pullV2Tag(tag, taggedName string) (verified bool, err error) { logrus.Debugf("Pulling tag from V2 registry: %q", tag) out := p.config.OutStream manSvc, err := p.repo.Manifests(context.Background()) if err != nil { return false, err } manifest, err := manSvc.GetByTag(tag) if err != nil { return false, err } verified, err = p.validateManifest(manifest, tag) if err != nil { return false, err } if verified { logrus.Printf("Image manifest for %s has been verified", taggedName) } // By using a pipeWriter for each of the downloads to write their progress // to, we can avoid an issue where this function returns an error but // leaves behind running download goroutines. By splitting the writer // with a pipe, we can close the pipe if there is any error, consequently // causing each download to cancel due to an error writing to this pipe. pipeReader, pipeWriter := io.Pipe() go func() { if _, err := io.Copy(out, pipeReader); err != nil { logrus.Errorf("error copying from layer download progress reader: %s", err) } }() defer func() { if err != nil { // All operations on the pipe are synchronous. This call will wait // until all current readers/writers are done using the pipe then // set the error. All successive reads/writes will return with this // error. pipeWriter.CloseWithError(errors.New("download canceled")) } }() out.Write(p.sf.FormatStatus(tag, "Pulling from %s", p.repo.Name())) downloads := make([]downloadInfo, len(manifest.FSLayers)) layerIDs := []string{} defer func() { p.graph.Release(p.sessionID, layerIDs...) }() for i := len(manifest.FSLayers) - 1; i >= 0; i-- { img, err := image.NewImgJSON([]byte(manifest.History[i].V1Compatibility)) if err != nil { logrus.Debugf("error getting image v1 json: %v", err) return false, err } downloads[i].img = img downloads[i].digest = manifest.FSLayers[i].BlobSum p.graph.Retain(p.sessionID, img.ID) layerIDs = append(layerIDs, img.ID) // Check if exists if p.graph.Exists(img.ID) { logrus.Debugf("Image already exists: %s", img.ID) continue } out.Write(p.sf.FormatProgress(stringid.TruncateID(img.ID), "Pulling fs layer", nil)) downloads[i].err = make(chan error) downloads[i].out = pipeWriter go p.download(&downloads[i]) } var tagUpdated bool for i := len(downloads) - 1; i >= 0; i-- { d := &downloads[i] if d.err != nil { if err := <-d.err; err != nil { return false, err } } if d.layer != nil { // if tmpFile is empty assume download and extracted elsewhere defer os.Remove(d.tmpFile.Name()) defer d.tmpFile.Close() d.tmpFile.Seek(0, 0) if d.tmpFile != nil { reader := progressreader.New(progressreader.Config{ In: d.tmpFile, Out: out, Formatter: p.sf, Size: d.size, NewLines: false, ID: stringid.TruncateID(d.img.ID), Action: "Extracting", }) err = p.graph.Register(d.img, reader) if err != nil { return false, err } if err := p.graph.SetDigest(d.img.ID, d.digest); err != nil { return false, err } // FIXME: Pool release here for parallel tag pull (ensures any downloads block until fully extracted) } out.Write(p.sf.FormatProgress(stringid.TruncateID(d.img.ID), "Pull complete", nil)) tagUpdated = true } else { out.Write(p.sf.FormatProgress(stringid.TruncateID(d.img.ID), "Already exists", nil)) } } manifestDigest, _, err := digestFromManifest(manifest, p.repoInfo.LocalName) if err != nil { return false, err } // Check for new tag if no layers downloaded if !tagUpdated { repo, err := p.Get(p.repoInfo.LocalName) if err != nil { return false, err } if repo != nil { if _, exists := repo[tag]; !exists { tagUpdated = true } } else { tagUpdated = true } } if verified && tagUpdated { out.Write(p.sf.FormatStatus(p.repo.Name()+":"+tag, "The image you are pulling has been verified. Important: image verification is a tech preview feature and should not be relied on to provide security.")) } if utils.DigestReference(tag) { // TODO(stevvooe): Ideally, we should always set the digest so we can // use the digest whether we pull by it or not. Unfortunately, the tag // store treats the digest as a separate tag, meaning there may be an // untagged digest image that would seem to be dangling by a user. if err = p.SetDigest(p.repoInfo.LocalName, tag, downloads[0].img.ID); err != nil { return false, err } } else { // only set the repository/tag -> image ID mapping when pulling by tag (i.e. not by digest) if err = p.Tag(p.repoInfo.LocalName, tag, downloads[0].img.ID, true); err != nil { return false, err } } if manifestDigest != "" { out.Write(p.sf.FormatStatus("", "Digest: %s", manifestDigest)) } return tagUpdated, nil } // verifyTrustedKeys checks the keys provided against the trust store, // ensuring that the provided keys are trusted for the namespace. The keys // provided from this method must come from the signatures provided as part of // the manifest JWS package, obtained from unpackSignedManifest or libtrust. func (p *v2Puller) verifyTrustedKeys(namespace string, keys []libtrust.PublicKey) (verified bool, err error) { if namespace[0] != '/' { namespace = "/" + namespace } for _, key := range keys { b, err := key.MarshalJSON() if err != nil { return false, fmt.Errorf("error marshalling public key: %s", err) } // Check key has read/write permission (0x03) v, err := p.trustService.CheckKey(namespace, b, 0x03) if err != nil { vErr, ok := err.(trust.NotVerifiedError) if !ok { return false, fmt.Errorf("error running key check: %s", err) } logrus.Debugf("Key check result: %v", vErr) } verified = v } if verified { logrus.Debug("Key check result: verified") } return } func (p *v2Puller) validateManifest(m *manifest.SignedManifest, tag string) (verified bool, err error) { // If pull by digest, then verify the manifest digest. NOTE: It is // important to do this first, before any other content validation. If the // digest cannot be verified, don't even bother with those other things. if manifestDigest, err := digest.ParseDigest(tag); err == nil { verifier, err := digest.NewDigestVerifier(manifestDigest) if err != nil { return false, err } payload, err := m.Payload() if err != nil { return false, err } if _, err := verifier.Write(payload); err != nil { return false, err } if !verifier.Verified() { err := fmt.Errorf("image verification failed for digest %s", manifestDigest) logrus.Error(err) return false, err } } // TODO(tiborvass): what's the usecase for having manifest == nil and err == nil ? Shouldn't be the error be "DoesNotExist" ? if m == nil { return false, fmt.Errorf("image manifest does not exist for tag %q", tag) } if m.SchemaVersion != 1 { return false, fmt.Errorf("unsupported schema version %d for tag %q", m.SchemaVersion, tag) } if len(m.FSLayers) != len(m.History) { return false, fmt.Errorf("length of history not equal to number of layers for tag %q", tag) } if len(m.FSLayers) == 0 { return false, fmt.Errorf("no FSLayers in manifest for tag %q", tag) } keys, err := manifest.Verify(m) if err != nil { return false, fmt.Errorf("error verifying manifest for tag %q: %v", tag, err) } verified, err = p.verifyTrustedKeys(m.Name, keys) if err != nil { return false, fmt.Errorf("error verifying manifest keys: %v", err) } return verified, nil }