distribution/docs/tokens.go
Stephen J Day c02f1a5507 Move registry package out of repo root
Since the repo is no longer just the registry, we are moving the registry web
application package out of the repo root into a sub-package. We may break down
the registry package further to separate webapp components and bring the client
package under it. This change accomplishes the task of freeing up the repo root
for a distribution-oriented package. A stub doc.go file is left in place to
declare intent.

Signed-off-by: Stephen J Day <stephen.day@docker.com>
2015-01-06 10:40:22 -08:00

65 lines
2 KiB
Go

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
}