[WebCrypto] Throw syntaxError if keyUsage is empty in ImportKey

content/child/webcrypto/nss/aes_key_nss.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/nss/aes_key_nss.h"
 
 #include "base/logging.h"
 #include "content/child/webcrypto/crypto_data.h"
 #include "content/child/webcrypto/jwk.h"
 #include "content/child/webcrypto/nss/key_nss.h"
@@ skipping 54 matching lines @@
       return CheckKeyCreationUsages(all_key_usages_, usages);
     default:
       return Status::ErrorUnsupportedImportKeyFormat();
   }
 }
 Status AesAlgorithm::ImportKeyRaw(const CryptoData& key_data,
                                   const blink::WebCryptoAlgorithm& algorithm,
                                   bool extractable,
                                   blink::WebCryptoKeyUsageMask usages,
                                   blink::WebCryptoKey* key) const {
+  if (usages == 0)
+    return Status::ErrorImportKeyEmptyUsages();

[eroman, 2014/12/08 18:46:32]

Move this into VerifyKeyUsagesBeforeImportKey() similar to the other usage
checks. (Necessary for early failure when unwrapping keys).

In fact it would be best to just modify the CheckKeyCreationUsages() helper to
do the check. Add for instance a bool parameter indicating if empty usages are
allowed.

+
   const unsigned int keylen_bytes = key_data.byte_length();
   Status status = VerifyAesKeyLengthForImport(keylen_bytes);
   if (status.IsError())
     return status;
 
   // No possibility of overflow.
   unsigned int keylen_bits = keylen_bytes * 8;
 
   return ImportKeyRawNss(
       key_data,
       blink::WebCryptoKeyAlgorithm::createAes(algorithm.id(), keylen_bits),
       extractable, usages, import_mechanism_, import_flags_, key);
 }
 
 Status AesAlgorithm::ImportKeyJwk(const CryptoData& key_data,
                                   const blink::WebCryptoAlgorithm& algorithm,
                                   bool extractable,
                                   blink::WebCryptoKeyUsageMask usages,
                                   blink::WebCryptoKey* key) const {
+  if (usages == 0)
+    return Status::ErrorImportKeyEmptyUsages();
+
   std::vector<uint8_t> raw_data;
   Status status = ReadAesSecretKeyJwk(key_data, jwk_suffix_, extractable,
                                       usages, &raw_data);
   if (status.IsError())
     return status;
 
   return ImportKeyRaw(CryptoData(raw_data), algorithm, extractable, usages,
                       key);
 }
 
@@ skipping 29 matching lines @@
     blink::WebCryptoKeyUsageMask usages,
     const CryptoData& key_data,
     blink::WebCryptoKey* key) const {
   return ImportKeyRaw(key_data, CreateAlgorithm(algorithm.id()), extractable,
                       usages, key);
 }
 
 }  // namespace webcrypto
 
 }  // namespace content