| // Copyright 2021 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/hybrid/internal/hpke_decrypt_boringssl.h" |
| |
| #include <string> |
| #include <utility> |
| |
| #include "absl/status/status.h" |
| #include "absl/strings/str_cat.h" |
| #include "openssl/base.h" |
| #include "openssl/err.h" |
| #include "openssl/hpke.h" |
| #include "tink/hybrid/internal/hpke_util_boringssl.h" |
| #include "tink/subtle/subtle_util.h" |
| #include "tink/util/status.h" |
| #include "tink/util/statusor.h" |
| #include "proto/hpke.pb.h" |
| |
| namespace crypto { |
| namespace tink { |
| namespace internal { |
| |
| util::StatusOr<std::unique_ptr<HpkeDecryptBoringSsl>> HpkeDecryptBoringSsl::New( |
| const google::crypto::tink::HpkeParams& params, |
| const HpkeKeyBoringSsl& hpke_key, absl::string_view encapsulated_key, |
| absl::string_view context_info) { |
| auto hpke_decrypt = absl::WrapUnique(new HpkeDecryptBoringSsl()); |
| util::Status status = |
| hpke_decrypt->Init(params, hpke_key, encapsulated_key, context_info); |
| if (!status.ok()) { |
| return status; |
| } |
| return std::move(hpke_decrypt); |
| } |
| |
| util::Status HpkeDecryptBoringSsl::Init( |
| const google::crypto::tink::HpkeParams& params, |
| const HpkeKeyBoringSsl& hpke_key, absl::string_view encapsulated_key, |
| absl::string_view context_info) { |
| util::StatusOr<const EVP_HPKE_KEM *> kem = KemParam(params); |
| if (!kem.ok()) { |
| return kem.status(); |
| } |
| if (params.kem() != hpke_key.kem()) { |
| return util::Status( |
| absl::StatusCode::kInvalidArgument, |
| absl::StrCat("Specified KEM parameter '", params.kem(), |
| "' does not match given HPKE key's KEM parameter '", |
| hpke_key.kem(), "'.")); |
| } |
| util::StatusOr<const EVP_HPKE_KDF *> kdf = KdfParam(params); |
| if (!kdf.ok()) { |
| return kdf.status(); |
| } |
| util::StatusOr<const EVP_HPKE_AEAD *> aead = AeadParam(params); |
| if (!aead.ok()) { |
| return aead.status(); |
| } |
| if (!EVP_HPKE_CTX_setup_recipient( |
| recipient_ctx_.get(), hpke_key.recipient_private_key(), *kdf, *aead, |
| reinterpret_cast<const uint8_t *>(encapsulated_key.data()), |
| encapsulated_key.size(), |
| reinterpret_cast<const uint8_t *>(context_info.data()), |
| context_info.size())) { |
| return util::Status(absl::StatusCode::kUnknown, |
| "Unable to set up BoringSSL HPKE recipient context."); |
| } |
| return util::OkStatus(); |
| } |
| |
| util::StatusOr<std::string> HpkeDecryptBoringSsl::Decrypt( |
| absl::string_view ciphertext, absl::string_view associated_data) { |
| std::string plaintext; |
| subtle::ResizeStringUninitialized(&plaintext, ciphertext.size()); |
| size_t plaintext_size; |
| if (!EVP_HPKE_CTX_open( |
| recipient_ctx_.get(), reinterpret_cast<uint8_t *>(&plaintext[0]), |
| &plaintext_size, plaintext.size(), |
| reinterpret_cast<const uint8_t *>(ciphertext.data()), |
| ciphertext.size(), |
| reinterpret_cast<const uint8_t *>(associated_data.data()), |
| associated_data.size())) { |
| return util::Status(absl::StatusCode::kUnknown, |
| "BoringSSL HPKE decryption failed."); |
| } |
| subtle::ResizeStringUninitialized(&plaintext, plaintext_size); |
| return plaintext; |
| } |
| |
| } // namespace internal |
| } // namespace tink |
| } // namespace crypto |