Serializes upload state to an HMAC token for subsequent requests

To support clustered registry, upload UUIDs must be recognizable by
registries that did not issue the UUID. By creating an HMAC verifiable
upload state token, registries can validate upload requests that other
instances authorized. The tokenProvider interface could also use a redis
store or other system for token handling in the future.

api_test.go

@@ -459,6 +459,8 @@ func pushLayer(t *testing.T, ub *v2.URLBuilder, name string, dgst digest.Digest,
 	}
 
 	u.RawQuery = url.Values{
+		"_state": u.Query()["_state"],
+
 		"digest": []string{dgst.String()},
 
 		// TODO(stevvooe): Layer upload can be completed with and without size

app.go

@@ -29,6 +29,8 @@ type App struct {
 	// services contains the main services instance for the application.
 	services *storage.Services
 
+	tokenProvider tokenProvider
+
 	accessController auth.AccessController
 }
 
@@ -62,6 +64,7 @@ func NewApp(configuration configuration.Configuration) *App {
 
 	app.driver = driver
 	app.services = storage.NewServices(app.driver)
+	app.tokenProvider = newHMACTokenProvider(configuration.Cluster.Secret)
 
 	authType := configuration.Auth.Type()
 

configuration/configuration.go

@@ -33,6 +33,12 @@ type Configuration struct {
 		// Addr specifies the bind address for the registry instance.
 		Addr string `yaml:"addr"`
 	} `yaml:"http"`
+
+	// Cluster contains configuration parameters for clustering the registry.
+	Cluster struct {
+		// Secret specifies the secret key which HMAC tokens are created with.
+		Secret string `yaml:"secret"`
+	} `yaml:"cluster"`
 }
 
 // v0_1Configuration is a Version 0.1 Configuration struct

layerupload.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"io"
 	"net/http"
+	"net/url"
 	"strconv"
 
 	"github.com/Sirupsen/logrus"
@@ -32,9 +33,17 @@ func layerUploadDispatcher(ctx *Context, r *http.Request) http.Handler {
 	if luh.UUID != "" {
 		luh.log = luh.log.WithField("uuid", luh.UUID)
 
-		layers := ctx.services.Layers()
-		upload, err := layers.Resume(luh.UUID)
+		state, err := ctx.tokenProvider.LayerUploadStateFromToken(r.FormValue("_state"))
+		if err != nil {
+			return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+				logrus.Infof("error resolving upload: %v", err)
+				w.WriteHeader(http.StatusInternalServerError)
+				luh.Errors.Push(v2.ErrorCodeUnknown, err)
+			})
+		}
 
+		layers := ctx.services.Layers()
+		upload, err := layers.Resume(state)
 		if err != nil && err != storage.ErrLayerUploadUnknown {
 			return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 				logrus.Infof("error resolving upload: %v", err)
@@ -162,7 +171,14 @@ func (luh *layerUploadHandler) CancelLayerUpload(w http.ResponseWriter, r *http.
 // chunk responses. This sets the correct headers but the response status is
 // left to the caller.
 func (luh *layerUploadHandler) layerUploadResponse(w http.ResponseWriter, r *http.Request) error {
-	uploadURL, err := luh.urlBuilder.BuildBlobUploadChunkURL(luh.Upload.Name(), luh.Upload.UUID())
+	values := make(url.Values)
+	stateToken, err := luh.Context.tokenProvider.LayerUploadStateToToken(storage.LayerUploadState{Name: luh.Upload.Name(), UUID: luh.Upload.UUID(), Offset: luh.Upload.Offset()})
+	if err != nil {
+		logrus.Infof("error building upload state token: %s", err)
+		return err
+	}
+	values.Set("_state", stateToken)
+	uploadURL, err := luh.urlBuilder.BuildBlobUploadChunkURL(luh.Upload.Name(), luh.Upload.UUID(), values)
 	if err != nil {
 		logrus.Infof("error building upload url: %s", err)
 		return err

storage/layer_test.go

@@ -58,7 +58,7 @@ func TestSimpleLayerUpload(t *testing.T) {
 	}
 
 	// Do a resume, get unknown upload
-	layerUpload, err = ls.Resume(layerUpload.UUID())
+	layerUpload, err = ls.Resume(LayerUploadState{Name: layerUpload.Name(), UUID: layerUpload.UUID(), Offset: layerUpload.Offset()})
 	if err != ErrLayerUploadUnknown {
 		t.Fatalf("unexpected error resuming upload, should be unkown: %v", err)
 	}
@@ -90,7 +90,7 @@ func TestSimpleLayerUpload(t *testing.T) {
 	layerUpload.Close()
 
 	// Do a resume, for good fun
-	layerUpload, err = ls.Resume(layerUpload.UUID())
+	layerUpload, err = ls.Resume(LayerUploadState{Name: layerUpload.Name(), UUID: layerUpload.UUID(), Offset: layerUpload.Offset()})
 	if err != nil {
 		t.Fatalf("unexpected error resuming upload: %v", err)
 	}
@@ -103,7 +103,7 @@ func TestSimpleLayerUpload(t *testing.T) {
 	}
 
 	// After finishing an upload, it should no longer exist.
-	if _, err := ls.Resume(layerUpload.UUID()); err != ErrLayerUploadUnknown {
+	if _, err := ls.Resume(LayerUploadState{Name: layerUpload.Name(), UUID: layerUpload.UUID(), Offset: layerUpload.Offset()}); err != ErrLayerUploadUnknown {
 		t.Fatalf("expected layer upload to be unknown, got %v", err)
 	}
 

storage/layerstore.go

@@ -76,8 +76,8 @@ func (ls *layerStore) Upload(name string) (LayerUpload, error) {
 
 // Resume continues an in progress layer upload, returning the current
 // state of the upload.
-func (ls *layerStore) Resume(uuid string) (LayerUpload, error) {
-	lus, err := ls.uploadStore.GetState(uuid)
+func (ls *layerStore) Resume(lus LayerUploadState) (LayerUpload, error) {
+	_, err := ls.uploadStore.GetState(lus.UUID)
 
 	if err != nil {
 		return nil, err

storage/layerupload.go

@@ -1,8 +1,8 @@
 package storage
 
 import (
-	"encoding/json"
 	"fmt"
+	"io"
 	"io/ioutil"
 	"os"
 	"path/filepath"
@@ -13,8 +13,6 @@ import (
 	"github.com/docker/distribution/manifest"
 	"github.com/docker/distribution/storagedriver"
 	"github.com/docker/docker/pkg/tarsum"
-
-	"io"
 )
 
 // LayerUploadState captures the state serializable state of the layer upload.
@@ -61,7 +59,6 @@ type layerUploadStore interface {
 	New(name string) (LayerUploadState, error)
 	Open(uuid string) (layerFile, error)
 	GetState(uuid string) (LayerUploadState, error)
-	SaveState(lus LayerUploadState) error
 	DeleteState(uuid string) error
 }
 
@@ -171,11 +168,6 @@ func (luc *layerUploadController) Write(p []byte) (int, error) {
 
 	luc.LayerUploadState.Offset += int64(n)
 
-	if err := luc.uploadStore.SaveState(luc.LayerUploadState); err != nil {
-		// TODO(stevvooe): This failure case may require more thought.
-		return n, err
-	}
-
 	return n, err
 }
 
@@ -384,10 +376,6 @@ func (llufs *localFSLayerUploadStore) New(name string) (LayerUploadState, error)
 		return lus, err
 	}
 
-	if err := llufs.SaveState(lus); err != nil {
-		return lus, err
-	}
-
 	return lus, nil
 }
 
@@ -402,43 +390,18 @@ func (llufs *localFSLayerUploadStore) Open(uuid string) (layerFile, error) {
 }
 
 func (llufs *localFSLayerUploadStore) GetState(uuid string) (LayerUploadState, error) {
-	// TODO(stevvoe): Storing this state on the local file system is an
-	// intermediate stop gap. This technique is unlikely to handle any kind of
-	// concurrency very well.
-
 	var lus LayerUploadState
-	fp, err := os.Open(llufs.path(uuid, "state.json"))
-	if err != nil {
+
+	if _, err := os.Stat(llufs.path(uuid, "")); err != nil {
 		if os.IsNotExist(err) {
 			return lus, ErrLayerUploadUnknown
 		}
 
 		return lus, err
 	}
-	defer fp.Close()
-
-	dec := json.NewDecoder(fp)
-	if err := dec.Decode(&lus); err != nil {
-		return lus, err
-	}
-
 	return lus, nil
 }
 
-func (llufs *localFSLayerUploadStore) SaveState(lus LayerUploadState) error {
-	p, err := json.Marshal(lus)
-	if err != nil {
-		return err
-	}
-
-	err = ioutil.WriteFile(llufs.path(lus.UUID, "state.json"), p, 0644)
-	if os.IsNotExist(err) {
-		return ErrLayerUploadUnknown
-	}
-
-	return err
-}
-
 func (llufs *localFSLayerUploadStore) DeleteState(uuid string) error {
 	if err := os.RemoveAll(llufs.path(uuid, "")); err != nil {
 		if os.IsNotExist(err) {

storage/manifeststore_test.go

@@ -153,6 +153,6 @@ func (mockedExistenceLayerService) Upload(name string) (LayerUpload, error) {
 	panic("not implemented")
 }
 
-func (mockedExistenceLayerService) Resume(uuid string) (LayerUpload, error) {
+func (mockedExistenceLayerService) Resume(lus LayerUploadState) (LayerUpload, error) {
 	panic("not implemented")
 }

storage/services.go

@@ -83,5 +83,5 @@ type LayerService interface {
 
 	// Resume continues an in progress layer upload, returning the current
 	// state of the upload.
-	Resume(uuid string) (LayerUpload, error)
+	Resume(layerUploadState LayerUploadState) (LayerUpload, error)
 }

tokens.go

@@ -0,0 +1,65 @@
+package registry
+
+import (
+	"crypto/hmac"
+	"crypto/sha256"
+	"encoding/base64"
+	"encoding/json"
+	"fmt"
+
+	"github.com/docker/distribution/storage"
+)
+
+// tokenProvider contains methods for serializing and deserializing state from token strings.
+type tokenProvider interface {
+	// LayerUploadStateFromToken retrieves the LayerUploadState for a given state token.
+	LayerUploadStateFromToken(stateToken string) (storage.LayerUploadState, error)
+
+	// LayerUploadStateToToken returns a token string representing the given LayerUploadState.
+	LayerUploadStateToToken(layerUploadState storage.LayerUploadState) (string, error)
+}
+
+type hmacTokenProvider struct {
+	secret string
+}
+
+func newHMACTokenProvider(secret string) tokenProvider {
+	return &hmacTokenProvider{secret: secret}
+}
+
+// LayerUploadStateFromToken deserializes the given HMAC stateToken and validates the prefix HMAC
+func (ts *hmacTokenProvider) LayerUploadStateFromToken(stateToken string) (storage.LayerUploadState, error) {
+	var lus storage.LayerUploadState
+
+	tokenBytes, err := base64.URLEncoding.DecodeString(stateToken)
+	if err != nil {
+		return lus, err
+	}
+	mac := hmac.New(sha256.New, []byte(ts.secret))
+
+	if len(tokenBytes) < mac.Size() {
+		return lus, fmt.Errorf("Invalid token")
+	}
+
+	macBytes := tokenBytes[:mac.Size()]
+	messageBytes := tokenBytes[mac.Size():]
+
+	mac.Write(messageBytes)
+	if !hmac.Equal(mac.Sum(nil), macBytes) {
+		return lus, fmt.Errorf("Invalid token")
+	}
+
+	if err := json.Unmarshal(messageBytes, &lus); err != nil {
+		return lus, err
+	}
+
+	return lus, nil
+}
+
+// LayerUploadStateToToken serializes the given LayerUploadState to JSON with an HMAC prepended
+func (ts *hmacTokenProvider) LayerUploadStateToToken(lus storage.LayerUploadState) (string, error) {
+	mac := hmac.New(sha256.New, []byte(ts.secret))
+	stateJSON := fmt.Sprintf("{\"Name\": \"%s\", \"UUID\": \"%s\", \"Offset\": %d}", lus.Name, lus.UUID, lus.Offset)
+	mac.Write([]byte(stateJSON))
+	return base64.URLEncoding.EncodeToString(append(mac.Sum(nil), stateJSON...)), nil
+}