update to use containerd seccomp package

Signed-off-by: Jess Frazelle <acidburn@microsoft.com>

vendor/github.com/docker/distribution/registry/handlers/hmac.go

@@ -1,74 +0,0 @@
-package handlers
-
-import (
-	"crypto/hmac"
-	"crypto/sha256"
-	"encoding/base64"
-	"encoding/json"
-	"fmt"
-	"time"
-)
-
-// blobUploadState captures the state serializable state of the blob upload.
-type blobUploadState struct {
-	// name is the primary repository under which the blob will be linked.
-	Name string
-
-	// UUID identifies the upload.
-	UUID string
-
-	// offset contains the current progress of the upload.
-	Offset int64
-
-	// StartedAt is the original start time of the upload.
-	StartedAt time.Time
-}
-
-type hmacKey string
-
-var errInvalidSecret = fmt.Errorf("invalid secret")
-
-// unpackUploadState unpacks and validates the blob upload state from the
-// token, using the hmacKey secret.
-func (secret hmacKey) unpackUploadState(token string) (blobUploadState, error) {
-	var state blobUploadState
-
-	tokenBytes, err := base64.URLEncoding.DecodeString(token)
-	if err != nil {
-		return state, err
-	}
-	mac := hmac.New(sha256.New, []byte(secret))
-
-	if len(tokenBytes) < mac.Size() {
-		return state, errInvalidSecret
-	}
-
-	macBytes := tokenBytes[:mac.Size()]
-	messageBytes := tokenBytes[mac.Size():]
-
-	mac.Write(messageBytes)
-	if !hmac.Equal(mac.Sum(nil), macBytes) {
-		return state, errInvalidSecret
-	}
-
-	if err := json.Unmarshal(messageBytes, &state); err != nil {
-		return state, err
-	}
-
-	return state, nil
-}
-
-// packUploadState packs the upload state signed with and hmac digest using
-// the hmacKey secret, encoding to url safe base64. The resulting token can be
-// used to share data with minimized risk of external tampering.
-func (secret hmacKey) packUploadState(lus blobUploadState) (string, error) {
-	mac := hmac.New(sha256.New, []byte(secret))
-	p, err := json.Marshal(lus)
-	if err != nil {
-		return "", err
-	}
-
-	mac.Write(p)
-
-	return base64.URLEncoding.EncodeToString(append(mac.Sum(nil), p...)), nil
-}