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

content/renderer/webcrypto/webcrypto_impl_openssl.cc

Index: content/renderer/webcrypto/webcrypto_impl_openssl.cc
diff --git a/content/renderer/webcrypto/webcrypto_impl_openssl.cc b/content/renderer/webcrypto/webcrypto_impl_openssl.cc
index 3170b28b987aac50f1045c9088816e453c59cb05..fb3d302bf8d474f27f7ddbceda9777f7dde19adb 100644
--- a/content/renderer/webcrypto/webcrypto_impl_openssl.cc
+++ b/content/renderer/webcrypto/webcrypto_impl_openssl.cc
@@ -157,6 +157,24 @@ bool AesCbcEncryptDecrypt(CipherOperation cipher_operation,
   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(); }
@@ -370,10 +388,18 @@ 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;
 }