[webcrypto] Reject AES-GCM tag lengths other than 32, 64, 96, 104, 112, 120, 128.

content/renderer/webcrypto/webcrypto_util.h

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_RENDERER_WEBCRYPTO_WEBCRYPTO_UTIL_H_
 #define CONTENT_RENDERER_WEBCRYPTO_WEBCRYPTO_UTIL_H_
 
 #include <string>
 #include <vector>
 #include "base/basictypes.h"
@@ skipping 127 matching lines @@
   // question was unsupported, some parameter combination was unsupported, or
   // something has not yet been implemented.
   static Status ErrorUnsupported();
 
   // Something unexpected happened in the code, which implies there is a
   // source-level bug. These should not happen, but safer to fail than simply
   // DCHECK.
   static Status ErrorUnexpected();
 
   // The authentication tag length specified for AES-GCM encrypt/decrypt was
-  // either greater than 128 bits, or it was not a multiple of 8 bits.
-  // (zero length is allowed).
+  // not 32, 64, 96, 104, 112, 120, or 128.
   static Status ErrorInvalidAesGcmTagLength();
 
   // The "publicExponent" used to generate a key was invalid: either no bytes
   // were specified, or the number was too large to fit into an "unsigned long"
   // (implemention limitation), or the exponent was zero.
   static Status ErrorGenerateKeyPublicExponent();
 
   // The algorithm was null when importing a raw-formatted key. In this case it
   // is required.
   static Status ErrorMissingAlgorithmImportRawKey();
@@ skipping 99 matching lines @@
     uint8 tag_length_bytes);
 
 // Returns the internal block size for SHA-*
 unsigned int ShaBlockSizeBytes(blink::WebCryptoAlgorithmId hash_id);
 
 }  // namespace webcrypto
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_WEBCRYPTO_WEBCRYPTO_UTIL_H_