| // Copyright 2019 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 "storage/browser/quota/padding_key.h" |
| |
| #include <cstdint> |
| #include <vector> |
| |
| #include "base/no_destructor.h" |
| #include "crypto/hmac.h" |
| |
| using crypto::SymmetricKey; |
| |
| namespace storage { |
| |
| namespace { |
| |
| const SymmetricKey::Algorithm kPaddingKeyAlgorithm = SymmetricKey::AES; |
| |
| // The range of the padding added to response sizes for opaque resources. |
| // Increment the CacheStorage padding version if changed. |
| constexpr uint64_t kPaddingRange = 14431 * 1024; |
| |
| std::unique_ptr<SymmetricKey>* GetPaddingKeyInternal() { |
| static base::NoDestructor<std::unique_ptr<SymmetricKey>> s_padding_key([] { |
| return SymmetricKey::GenerateRandomKey(kPaddingKeyAlgorithm, 128); |
| }()); |
| return s_padding_key.get(); |
| } |
| |
| } // namespace |
| |
| const SymmetricKey* GetDefaultPaddingKey() { |
| return GetPaddingKeyInternal()->get(); |
| } |
| |
| std::unique_ptr<SymmetricKey> CopyDefaultPaddingKey() { |
| return SymmetricKey::Import(kPaddingKeyAlgorithm, |
| (*GetPaddingKeyInternal())->key()); |
| } |
| |
| std::unique_ptr<SymmetricKey> DeserializePaddingKey( |
| const std::string& raw_key) { |
| return SymmetricKey::Import(kPaddingKeyAlgorithm, raw_key); |
| } |
| |
| std::string SerializeDefaultPaddingKey() { |
| return (*GetPaddingKeyInternal())->key(); |
| } |
| |
| void ResetPaddingKeyForTesting() { |
| *GetPaddingKeyInternal() = |
| SymmetricKey::GenerateRandomKey(kPaddingKeyAlgorithm, 128); |
| } |
| |
| int64_t ComputeResponsePadding(const std::string& response_url, |
| const crypto::SymmetricKey* padding_key, |
| bool has_metadata) { |
| DCHECK(!response_url.empty()); |
| |
| crypto::HMAC hmac(crypto::HMAC::SHA256); |
| CHECK(hmac.Init(padding_key)); |
| |
| std::string key = has_metadata ? response_url + "METADATA" : response_url; |
| uint64_t digest_start; |
| CHECK(hmac.Sign(key, reinterpret_cast<uint8_t*>(&digest_start), |
| sizeof(digest_start))); |
| return digest_start % kPaddingRange; |
| } |
| |
| } // namespace storage |