Address a FIXME.

Source/modules/crypto/NormalizeAlgorithm.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 390 matching lines @@
 bool getOptionalUint32(const Dictionary& raw, const char* propertyName, bool& hasValue, uint32_t& value, const ErrorContext& context, AlgorithmError* error)
 {
     double number;
     if (!getOptionalInteger(raw, propertyName, hasValue, number, 0, 0xFFFFFFFF, context, error))
         return false;
     if (hasValue)
         value = number;
     return true;
 }
 
+bool getOptionalUint8(const Dictionary& raw, const char* propertyName, bool& hasValue, uint8_t& value, const ErrorContext& context, AlgorithmError* error)
+{
+    double number;
+    if (!getOptionalInteger(raw, propertyName, hasValue, number, 0, 0xFF, context, error))
+        return false;
+    if (hasValue)
+        value = number;
+    return true;
+}
+
 bool getAlgorithmIdentifier(const Dictionary& raw, const char* propertyName, AlgorithmIdentifier& value, const ErrorContext& context, AlgorithmError* error)
 {
     // FIXME: This is not correct: http://crbug.com/438060
     //   (1) It may retrieve the property twice from the dictionary, whereas it
     //       should be reading the v8 value once to avoid issues with getters.
     //   (2) The value is stringified (whereas the spec says it should be an
     //       instance of DOMString).
     Dictionary dictionary;
     if (DictionaryHelper::get(raw, propertyName, dictionary) && !dictionary.isUndefinedOrNull()) {
         value.setDictionary(dictionary);
@@ skipping 162 matching lines @@
 
     params = adoptPtr(new WebCryptoAesCtrParams(length, counter.bytes(), counter.byteLength()));
     return true;
 }
 
 // Defined by the WebCrypto spec as:
 //
 //     dictionary AesGcmParams : Algorithm {
 //       required BufferSource iv;
 //       BufferSource additionalData;
-//       [EnforceRange] octet tagLength;  // May be 0-128
+//       [EnforceRange] octet tagLength;
 //     }
 bool parseAesGcmParams(const Dictionary& raw, OwnPtr<WebCryptoAlgorithmParams>& params, const ErrorContext& context, AlgorithmError* error)
 {
     BufferSource ivBufferSource;
     if (!getBufferSource(raw, "iv", ivBufferSource, context, error))
         return false;
 
     bool hasAdditionalData;
     BufferSource additionalDataBufferSource;
     if (!getOptionalBufferSource(raw, "additionalData", hasAdditionalData, additionalDataBufferSource, context, error))
         return false;
 
-    double tagLength;
+    uint8_t tagLength = 0;
     bool hasTagLength;
-    // FIXME: Layering -- should only enforce the WebIDL's "octet" range here, not the AES-CTR tagLength.
-    if (!getOptionalInteger(raw, "tagLength", hasTagLength, tagLength, 0, 128, context, error))
+    if (!getOptionalUint8(raw, "tagLength", hasTagLength, tagLength, context, error))
         return false;
 
     DOMArrayPiece iv(ivBufferSource);
     DOMArrayPiece additionalData(additionalDataBufferSource);
 
     params = adoptPtr(new WebCryptoAesGcmParams(iv.bytes(), iv.byteLength(), hasAdditionalData, additionalData.bytes(), additionalData.byteLength(), hasTagLength, tagLength));
     return true;
 }
 
 // Defined by the WebCrypto spec as:
@@ skipping 284 matching lines @@
 }
 
 } // namespace
 
 bool normalizeAlgorithm(const AlgorithmIdentifier& raw, WebCryptoOperation op, WebCryptoAlgorithm& algorithm, AlgorithmError* error)
 {
     return parseAlgorithmIdentifier(raw, op, algorithm, ErrorContext(), error);
 }
 
 } // namespace blink