WebCrypto: Fix a crash when passing invalid ArrayBufferView to importKey.

Source/modules/crypto/SubtleCrypto.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 107 matching lines @@
 }
 
 ScriptObject SubtleCrypto::importKey(const String& rawFormat, ArrayBufferView* keyData, const Dictionary& rawAlgorithm, bool extractable, const Vector<String>& rawKeyUsages, ExceptionState& es)
 {
     WebKit::WebCrypto* platformCrypto = WebKit::Platform::current()->crypto();
     if (!platformCrypto) {
         es.throwDOMException(NotSupportedError);
         return ScriptObject();
     }
 
+    if (!keyData) {
+        es.throwDOMException(TypeError);
+        return ScriptObject();
+    }
+
     WebKit::WebCryptoKeyUsageMask keyUsages;
     if (!Key::parseUsageMask(rawKeyUsages, keyUsages)) {
         es.throwDOMException(TypeError);
         return ScriptObject();
     }
 
     WebKit::WebCryptoKeyFormat format;
     if (!Key::parseFormat(rawFormat, format)) {
         es.throwDOMException(TypeError);
         return ScriptObject();
     }
 
     WebKit::WebCryptoAlgorithm algorithm;
     if (!normalizeAlgorithmForImportKey(rawAlgorithm, algorithm, es))
         return ScriptObject();
 
     const unsigned char* keyDataBytes = static_cast<unsigned char*>(keyData->baseAddress());
 
     RefPtr<KeyOperation> keyOp = KeyOperation::create();
     WebKit::WebCryptoKeyOperationResult result(keyOp.get());
     platformCrypto->importKey(format, keyDataBytes, keyData->byteLength(), algorithm, extractable, keyUsages, result);
     return keyOp->returnValue(es);
 }
 
 } // namespace WebCore