Refactor WebCrypto code

content/child/webcrypto/structured_clone.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/structured_clone.h"
+
+#include "base/logging.h"
+#include "content/child/webcrypto/algorithm_dispatch.h"
+#include "content/child/webcrypto/platform_crypto.h"
+#include "content/child/webcrypto/status.h"
+#include "content/child/webcrypto/webcrypto_util.h"
+#include "third_party/WebKit/public/platform/WebCryptoKeyAlgorithm.h"
+
+namespace content {
+
+namespace webcrypto {
+
+namespace {
+
+// Returns the key format to use for structured cloning.
+blink::WebCryptoKeyFormat GetCloneFormatForKeyType(
+    blink::WebCryptoKeyType type) {
+  switch (type) {
+    case blink::WebCryptoKeyTypeSecret:
+      return blink::WebCryptoKeyFormatRaw;
+    case blink::WebCryptoKeyTypePublic:
+      return blink::WebCryptoKeyFormatSpki;
+    case blink::WebCryptoKeyTypePrivate:
+      return blink::WebCryptoKeyFormatPkcs8;
+  }
+
+  NOTREACHED();
+  return blink::WebCryptoKeyFormatRaw;
+}
+
+// Converts a KeyAlgorithm into an equivalent Algorithm for import.
+blink::WebCryptoAlgorithm KeyAlgorithmToImportAlgorithm(
+    const blink::WebCryptoKeyAlgorithm& algorithm) {
+  switch (algorithm.paramsType()) {
+    case blink::WebCryptoKeyAlgorithmParamsTypeAes:
+      return CreateAlgorithm(algorithm.id());
+    case blink::WebCryptoKeyAlgorithmParamsTypeHmac:
+      return CreateHmacImportAlgorithm(algorithm.hmacParams()->hash().id());
+    case blink::WebCryptoKeyAlgorithmParamsTypeRsaHashed:
+      return CreateRsaHashedImportAlgorithm(
+          algorithm.id(), algorithm.rsaHashedParams()->hash().id());
+    case blink::WebCryptoKeyAlgorithmParamsTypeNone:
+      break;
+    default:
+      break;
+  }
+  return blink::WebCryptoAlgorithm::createNull();
+}
+
+// There is some duplicated information in the serialized format used by
+// structured clone (since the KeyAlgorithm is serialized separately from the
+// key data). Use this extra information to further validate what was
+// deserialized from the key data.
+//
+// A failure here implies either a bug in the code, or that the serialized data
+// was corrupted.
+bool ValidateDeserializedKey(const blink::WebCryptoKey& key,
+                             const blink::WebCryptoKeyAlgorithm& algorithm,
+                             blink::WebCryptoKeyType type) {
+  if (algorithm.id() != key.algorithm().id())
+    return false;
+
+  if (key.type() != type)
+    return false;
+
+  switch (algorithm.paramsType()) {
+    case blink::WebCryptoKeyAlgorithmParamsTypeAes:
+      if (algorithm.aesParams()->lengthBits() !=
+          key.algorithm().aesParams()->lengthBits())
+        return false;
+      break;
+    case blink::WebCryptoKeyAlgorithmParamsTypeRsaHashed:
+      if (algorithm.rsaHashedParams()->modulusLengthBits() !=
+          key.algorithm().rsaHashedParams()->modulusLengthBits())
+        return false;
+      if (algorithm.rsaHashedParams()->publicExponent().size() !=
+          key.algorithm().rsaHashedParams()->publicExponent().size())
+        return false;
+      if (memcmp(algorithm.rsaHashedParams()->publicExponent().data(),
+                 key.algorithm().rsaHashedParams()->publicExponent().data(),
+                 key.algorithm().rsaHashedParams()->publicExponent().size()) !=
+          0)
+        return false;
+      break;
+    case blink::WebCryptoKeyAlgorithmParamsTypeNone:
+    case blink::WebCryptoKeyAlgorithmParamsTypeHmac:
+      break;
+    default:
+      return false;
+  }
+
+  return true;
+}
+
+}  // namespace
+
+// Note that this function is called from the target Blink thread.
+bool SerializeKeyForClone(const blink::WebCryptoKey& key,
+                          blink::WebVector<uint8>* key_data) {
+  return PlatformSerializeKeyForClone(key, key_data);
+}
+
+// Note that this function is called from the target Blink thread.
+bool DeserializeKeyForClone(const blink::WebCryptoKeyAlgorithm& algorithm,
+                            blink::WebCryptoKeyType type,
+                            bool extractable,
+                            blink::WebCryptoKeyUsageMask usage_mask,
+                            const CryptoData& key_data,
+                            blink::WebCryptoKey* key) {
+  // TODO(eroman): This should not call into the platform crypto layer.
+  // Otherwise it runs the risk of stalling while the NSS/OpenSSL global locks
+  // are held.
+  //
+  // An alternate approach is to defer the key import until the key is used.
+  // However this means that any deserialization errors would have to be
+  // surfaced as WebCrypto errors, leading to slightly different behaviors. For
+  // instance you could clone a key which fails to be deserialized.
+  Status status = ImportKey(GetCloneFormatForKeyType(type),
+                            key_data,
+                            KeyAlgorithmToImportAlgorithm(algorithm),
+                            extractable,
+                            usage_mask,
+                            key);
+  if (status.IsError())
+    return false;
+  return ValidateDeserializedKey(*key, algorithm, type);
+}
+
+}  // namespace webcrypto
+
+}  // namespace content