[webcrypto] Properly fail-fast when importing RSA key as JWK with bad usages.

content/child/webcrypto/test/rsa_ssa_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 1182 matching lines @@
     RestoreJwkRsaDictionary(&dict);
 
     // Fail on empty parameter.
     dict.SetString(kKtyParmName[idx], "");
     EXPECT_EQ(Status::ErrorJwkEmptyBigInteger(kKtyParmName[idx]),
               ImportKeyJwkFromDict(dict, algorithm, false, usages, &key));
     RestoreJwkRsaDictionary(&dict);
   }
 }
 
+// Try importing an RSA-SSA key from JWK format, having specified both Sign and
+// Verify usage, and an invalid JWK.
+//
+// The test must fail with a usage error BEFORE attempting to read the JWK data.
+// Although both Sign and Verify are valid usages for RSA-SSA keys, it is
+// invalid to have them both at the same time for one key (since Sign applies to
+// private keys, whereas Verify applies to public keys).
+//
+// If the implementation does not fail fast, this test will crash dereferencing
+// invalid memory.
+TEST(WebCryptoRsaSsaTest, ImportRsaSsaJwkBadUsageFailFast) {
+  CryptoData bad_data(NULL, 128);  // Invalid buffer of length 128.
+
+  blink::WebCryptoKey key;
+  ASSERT_EQ(
+      Status::ErrorCreateKeyBadUsages(),
+      ImportKey(blink::WebCryptoKeyFormatJwk,
+                bad_data,
+                CreateRsaHashedImportAlgorithm(
+                    blink::WebCryptoAlgorithmIdRsaSsaPkcs1v1_5,
+                    blink::WebCryptoAlgorithmIdSha256),
+                true,
+                blink::WebCryptoKeyUsageVerify | blink::WebCryptoKeyUsageSign,
+                &key));
+}
+
 }  // namespace
 
 }  // namespace webcrypto
 
 }  // namespace content