| // Copyright 2019 Google LLC |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| // |
| /////////////////////////////////////////////////////////////////////////////// |
| #ifndef TINK_MAC_AES_CMAC_KEY_MANAGER_H_ |
| #define TINK_MAC_AES_CMAC_KEY_MANAGER_H_ |
| |
| #include <string> |
| |
| #include "absl/memory/memory.h" |
| #include "absl/status/status.h" |
| #include "absl/strings/str_cat.h" |
| #include "tink/chunked_mac.h" |
| #include "tink/core/key_type_manager.h" |
| #include "tink/key_manager.h" |
| #include "tink/mac.h" |
| #include "tink/mac/internal/chunked_mac_impl.h" |
| #include "tink/subtle/aes_cmac_boringssl.h" |
| #include "tink/subtle/random.h" |
| #include "tink/util/constants.h" |
| #include "tink/util/errors.h" |
| #include "tink/util/protobuf_helper.h" |
| #include "tink/util/secret_data.h" |
| #include "tink/util/status.h" |
| #include "tink/util/statusor.h" |
| #include "tink/util/validation.h" |
| #include "proto/aes_cmac.pb.h" |
| #include "proto/tink.pb.h" |
| |
| namespace crypto { |
| namespace tink { |
| |
| class AesCmacKeyManager |
| : public KeyTypeManager<google::crypto::tink::AesCmacKey, |
| google::crypto::tink::AesCmacKeyFormat, |
| List<Mac, ChunkedMac>> { |
| public: |
| class MacFactory : public PrimitiveFactory<Mac> { |
| crypto::tink::util::StatusOr<std::unique_ptr<Mac>> Create( |
| const google::crypto::tink::AesCmacKey& key) const override { |
| return subtle::AesCmacBoringSsl::New( |
| util::SecretDataFromStringView(key.key_value()), |
| key.params().tag_size()); |
| } |
| }; |
| |
| class ChunkedMacFactory : public PrimitiveFactory<ChunkedMac> { |
| crypto::tink::util::StatusOr<std::unique_ptr<ChunkedMac>> Create( |
| const google::crypto::tink::AesCmacKey& key) const override { |
| return internal::NewChunkedCmac(key); |
| } |
| }; |
| |
| AesCmacKeyManager() |
| : KeyTypeManager( |
| absl::make_unique<AesCmacKeyManager::MacFactory>(), |
| absl::make_unique<AesCmacKeyManager::ChunkedMacFactory>()) {} |
| |
| uint32_t get_version() const override { return 0; } |
| |
| google::crypto::tink::KeyData::KeyMaterialType key_material_type() |
| const override { |
| return google::crypto::tink::KeyData::SYMMETRIC; |
| } |
| |
| const std::string& get_key_type() const override { return key_type_; } |
| |
| crypto::tink::util::Status ValidateKey( |
| const google::crypto::tink::AesCmacKey& key) const override { |
| crypto::tink::util::Status status = |
| ValidateVersion(key.version(), get_version()); |
| if (!status.ok()) return status; |
| if (key.key_value().size() != kKeySizeInBytes) { |
| return crypto::tink::util::Status( |
| absl::StatusCode::kInvalidArgument, |
| "Invalid AesCmacKey: key_value wrong length."); |
| } |
| return ValidateParams(key.params()); |
| } |
| |
| crypto::tink::util::Status ValidateKeyFormat( |
| const google::crypto::tink::AesCmacKeyFormat& key_format) const override { |
| if (key_format.key_size() != kKeySizeInBytes) { |
| return crypto::tink::util::Status( |
| absl::StatusCode::kInvalidArgument, |
| "Invalid AesCmacKeyFormat: invalid key_size."); |
| } |
| return ValidateParams(key_format.params()); |
| } |
| |
| crypto::tink::util::StatusOr<google::crypto::tink::AesCmacKey> CreateKey( |
| const google::crypto::tink::AesCmacKeyFormat& key_format) const override { |
| google::crypto::tink::AesCmacKey key; |
| key.set_version(get_version()); |
| key.set_key_value( |
| subtle::Random::GetRandomBytes(key_format.key_size())); |
| *key.mutable_params() = key_format.params(); |
| return key; |
| } |
| |
| private: |
| crypto::tink::util::Status ValidateParams( |
| const google::crypto::tink::AesCmacParams& params) const { |
| if (params.tag_size() < kMinTagSizeInBytes) { |
| return util::Status(absl::StatusCode::kInvalidArgument, |
| absl::StrCat("Invalid AesCmacParams: tag_size ", |
| params.tag_size(), " is too small.")); |
| } |
| if (params.tag_size() > kMaxTagSizeInBytes) { |
| return util::Status(absl::StatusCode::kInvalidArgument, |
| absl::StrCat("Invalid AesCmacParams: tag_size ", |
| params.tag_size(), " is too big.")); |
| } |
| return util::OkStatus(); |
| } |
| |
| // Due to https://www.math.uwaterloo.ca/~ajmeneze/publications/tightness.pdf, |
| // we only allow key sizes of 256 bit. |
| const int kKeySizeInBytes = 32; |
| const int kMaxTagSizeInBytes = 16; |
| const int kMinTagSizeInBytes = 10; |
| |
| const std::string key_type_ = absl::StrCat( |
| kTypeGoogleapisCom, google::crypto::tink::AesCmacKey().GetTypeName()); |
| }; |
| |
| } // namespace tink |
| } // namespace crypto |
| |
| #endif // TINK_MAC_AES_CMAC_KEY_MANAGER_H_ |