Check for integer overflow when HMAC key length as bits cannot fit in an unsigned int.

content/child/webcrypto/test/hmac_unittest.cc

 // Copyright 2014 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.
 
 #include "base/logging.h"
 #include "base/stl_util.h"
 #include "content/child/webcrypto/algorithm_dispatch.h"
 #include "content/child/webcrypto/crypto_data.h"
 #include "content/child/webcrypto/status.h"
 #include "content/child/webcrypto/test/test_helpers.h"
@@ skipping 505 matching lines @@
   EXPECT_EQ(blink::WebCryptoKeyTypeSecret, key.type());
   EXPECT_EQ(0u, key.algorithm().hmacParams()->lengthBits());
 
   std::vector<uint8_t> exported_key_data;
   EXPECT_EQ(Status::Success(),
             ExportKey(blink::WebCryptoKeyFormatRaw, key, &exported_key_data));
 
   EXPECT_EQ(0u, exported_key_data.size());
 }
 
+// Import a huge hmac key (UINT_MAX bytes). This will fail before actually
+// reading the bytes, as the key is too large.
+TEST(WebCryptoHmacTest, ImportRawKeyTooLarge) {
+  CryptoData big_data(NULL, UINT_MAX);  // Invalid data of big length.
+
+  blink::WebCryptoKey key = blink::WebCryptoKey::createNull();
+  EXPECT_EQ(
+      Status::ErrorDataTooLarge(),
+      ImportKey(blink::WebCryptoKeyFormatRaw,
+                CryptoData(big_data),
+                CreateHmacImportAlgorithm(blink::WebCryptoAlgorithmIdSha1),
+                true,
+                blink::WebCryptoKeyUsageSign,
+                &key));
+}
+
 }  // namespace
 
 }  // namespace webcrypto
 
 }  // namespace content