Check that usage isn't empty when generateKey() is called

content/child/webcrypto/openssl/sym_key_openssl.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 "content/child/webcrypto/openssl/sym_key_openssl.h"
 
 #include <vector>
 #include <openssl/rand.h>
 
 #include "content/child/webcrypto/crypto_data.h"
 #include "content/child/webcrypto/generate_key_result.h"
 #include "content/child/webcrypto/openssl/key_openssl.h"
 #include "content/child/webcrypto/status.h"
 #include "crypto/openssl_util.h"
 #include "third_party/WebKit/public/platform/WebCryptoKeyAlgorithm.h"
 
 namespace content {
 
 namespace webcrypto {
 
 Status GenerateSecretKeyOpenSsl(const blink::WebCryptoKeyAlgorithm& algorithm,
                                 bool extractable,
                                 blink::WebCryptoKeyUsageMask usages,
                                 unsigned keylen_bytes,
                                 GenerateKeyResult* result) {
   crypto::OpenSSLErrStackTracer err_tracer(FROM_HERE);
 
   std::vector<unsigned char> random_bytes(keylen_bytes, 0);
 
+  if (usages == 0)
+    return Status::ErrorCreateKeyEmptyUsages();

[eroman, 2014/11/21 23:35:34]

Move this higher up, so the failure happens before allocating the random_bytes
array.

[nharper, 2014/11/22 00:26:45]

Done.

+
   if (keylen_bytes > 0) {
     if (!(RAND_bytes(&random_bytes[0], keylen_bytes)))
       return Status::OperationError();
   }
 
   result->AssignSecretKey(
       blink::WebCryptoKey::create(new SymKeyOpenSsl(CryptoData(random_bytes)),
                                   blink::WebCryptoKeyTypeSecret,
                                   extractable,
                                   algorithm,
@@ skipping 11 matching lines @@
                                      blink::WebCryptoKeyTypeSecret,
                                      extractable,
                                      algorithm,
                                      usages);
   return Status::Success();
 }
 
 }  // namespace webcrypto
 
 }  // namespace content