| // Copyright 2020 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. |
| // |
| //////////////////////////////////////////////////////////////////////////////// |
| #include "tink/subtle/prf/prf_set_util.h" |
| |
| #include <memory> |
| |
| #include "absl/memory/memory.h" |
| #include "absl/strings/str_cat.h" |
| #include "tink/subtle/mac/stateful_mac.h" |
| #include "tink/util/input_stream_util.h" |
| #include "tink/util/status.h" |
| #include "tink/util/statusor.h" |
| |
| namespace crypto { |
| namespace tink { |
| namespace subtle { |
| namespace { |
| |
| class PrfFromStreamingPrf : public Prf { |
| public: |
| explicit PrfFromStreamingPrf(std::unique_ptr<StreamingPrf> streaming_prf) |
| : streaming_prf_(std::move(streaming_prf)) {} |
| util::StatusOr<std::string> Compute(absl::string_view input, |
| size_t output_length) const override { |
| auto inputstream = streaming_prf_->ComputePrf(input); |
| auto output_result = ReadBytesFromStream(output_length, inputstream.get()); |
| if (!output_result.ok()) { |
| return output_result.status(); |
| } |
| std::string output = output_result.ValueOrDie(); |
| return output; |
| } |
| |
| private: |
| std::unique_ptr<StreamingPrf> streaming_prf_; |
| }; |
| |
| class PrfFromStatefulMacFactory : public Prf { |
| public: |
| explicit PrfFromStatefulMacFactory( |
| std::unique_ptr<StatefulMacFactory> stateful_mac_factory) |
| : stateful_mac_factory_(std::move(stateful_mac_factory)) {} |
| util::StatusOr<std::string> Compute(absl::string_view input, |
| size_t output_length) const override { |
| auto stateful_mac_result = stateful_mac_factory_->Create(); |
| if (!stateful_mac_result.ok()) { |
| return stateful_mac_result.status(); |
| } |
| auto stateful_mac = std::move(stateful_mac_result.ValueOrDie()); |
| auto status = stateful_mac->Update(input); |
| if (!status.ok()) { |
| return status; |
| } |
| auto output_result = stateful_mac->Finalize(); |
| if (!output_result.ok()) { |
| return output_result.status(); |
| } |
| std::string output = std::move(output_result.ValueOrDie()); |
| if (output.size() < output_length) { |
| return util::Status( |
| util::error::INVALID_ARGUMENT, |
| absl::StrCat("PRF only supports outputs up to ", output.size(), |
| " bytes, but ", output_length, " bytes were requested")); |
| } |
| return output.substr(0, output_length); |
| } |
| |
| private: |
| std::unique_ptr<StatefulMacFactory> stateful_mac_factory_; |
| }; |
| |
| } // namespace |
| |
| std::unique_ptr<Prf> CreatePrfFromStreamingPrf( |
| std::unique_ptr<StreamingPrf> streaming_prf) { |
| return absl::make_unique<PrfFromStreamingPrf>(std::move(streaming_prf)); |
| } |
| |
| std::unique_ptr<Prf> CreatePrfFromStatefulMacFactory( |
| std::unique_ptr<StatefulMacFactory> stateful_mac_factory) { |
| return absl::make_unique<PrfFromStatefulMacFactory>( |
| std::move(stateful_mac_factory)); |
| } |
| |
| } // namespace subtle |
| } // namespace tink |
| } // namespace crypto |