[webcrypto] Add symmetric key export for NSS and OpenSSL.

content/renderer/webcrypto/webcrypto_impl_openssl.cc

 // Copyright 2013 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/renderer/webcrypto/webcrypto_impl.h"
 
 #include <vector>
 #include <openssl/aes.h>
 #include <openssl/evp.h>
 #include <openssl/hmac.h>
@@ skipping 139 matching lines @@
   const unsigned final_output_len =
       static_cast<unsigned>(output_len) +
       static_cast<unsigned>(final_output_chunk_len);
   DCHECK_LE(final_output_len, output_max_len);
 
   webcrypto::ShrinkBuffer(buffer, final_output_len);
 
   return true;
 }
 
+bool ExportKeyInternalRaw(
+    const blink::WebCryptoKey& key,
+    blink::WebArrayBuffer* buffer) {
+
+  DCHECK(key.handle());
+  DCHECK(buffer);
+
+  if (key.type() != blink::WebCryptoKeyTypeSecret || !key.extractable())
+    return false;
+
+  SymKeyHandle* const sym_key = reinterpret_cast<SymKeyHandle*>(key.handle());
+
+  *buffer =
+      webcrypto::CreateArrayBuffer(&sym_key->key()[0], sym_key->key().size());

[eroman, 2013/12/05 01:47:53]

Is it ever possible for the key length to be 0?

[padolph, 2013/12/05 02:45:57]

Yes. Empty symmetric keys are supported and already used in the unit tests.

[eroman, 2013/12/05 02:53:58]

If the key is empty, then I don't think we should be taking the address of
element zero.

[padolph, 2013/12/05 03:34:16]

Done.

+
+  return true;
+}
+
 }  // namespace
 
 void WebCryptoImpl::Init() { crypto::EnsureOpenSSLInit(); }
 
 bool WebCryptoImpl::EncryptInternal(const blink::WebCryptoAlgorithm& algorithm,
                                     const blink::WebCryptoKey& key,
                                     const unsigned char* data,
                                     unsigned data_size,
                                     blink::WebArrayBuffer* buffer) {
   if (algorithm.id() == blink::WebCryptoAlgorithmIdAesCbc) {
@@ skipping 193 matching lines @@
       new SymKeyHandle(raw_key_data, raw_key_data_size),
       type, extractable, algorithm, usage_mask);
 
   return true;
 }
 
 bool WebCryptoImpl::ExportKeyInternal(
     blink::WebCryptoKeyFormat format,
     const blink::WebCryptoKey& key,
     blink::WebArrayBuffer* buffer) {
-  // TODO(padolph): Implement raw export
-  // TODO(padolph): Implement spki export
-  // TODO(padolph): Implement pkcs8 export
-  // TODO(padolph): Implement jwk export
+  switch (format) {
+    case blink::WebCryptoKeyFormatRaw:
+      return ExportKeyInternalRaw(key, buffer);
+    case blink::WebCryptoKeyFormatSpki:
+      // TODO(padolph): Implement spki export
+      return false;
+    case blink::WebCryptoKeyFormatPkcs8:
+      // TODO(padolph): Implement pkcs8 export
+      return false;
+    default:
+      return false;
+  }
   return false;
 }
 
 bool WebCryptoImpl::SignInternal(
     const blink::WebCryptoAlgorithm& algorithm,
     const blink::WebCryptoKey& key,
     const unsigned char* data,
     unsigned data_size,
     blink::WebArrayBuffer* buffer) {
 
@@ skipping 117 matching lines @@
     const blink::WebCryptoAlgorithm& algorithm,
     bool extractable,
     blink::WebCryptoKeyUsageMask usage_mask,
     blink::WebCryptoKey* key) {
   // TODO(padolph): Placeholder for OpenSSL implementation.
   // Issue http://crbug.com/267888.
   return false;
 }
 
 }  // namespace content