83eed0a886
Changes include: * CPU check has been broken up into a number of small libraries * BoringSSL option has been removed * Better abseil integration
113 lines
4.0 KiB
C++
113 lines
4.0 KiB
C++
// Copyright 2020 Google LLC
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include "crypto.h"
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#include "config.h"
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#include "absl/status/status.h"
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namespace cpu_check {
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namespace {
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constexpr unsigned char key[33] = "0123456789abcdef0123456789abcdef";
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}; // namespace
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absl::Status Crypto::Encrypt(const MalignBuffer &plain_text,
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MalignBuffer *cipher_text, CryptoPurse *purse) {
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memset(purse->i_vec, 0, sizeof(purse->i_vec));
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memcpy(purse->i_vec, plain_text.data(),
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std::min(plain_text.size(), sizeof(purse->i_vec)));
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int enc_len = 0;
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int enc_unused_len = 0;
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EVP_CIPHER_CTX *cipher_ctx = EVP_CIPHER_CTX_new();
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EVP_CipherInit_ex(cipher_ctx, EVP_aes_256_gcm(), NULL, key, purse->i_vec, 1);
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if (EVP_CipherUpdate(
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cipher_ctx,
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reinterpret_cast<unsigned char *>(cipher_text->data()),
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&enc_len, reinterpret_cast<const unsigned char *>(plain_text.data()),
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plain_text.size()) != 1) {
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return ReturnError("EVP_CipherUpdate", cipher_ctx);
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}
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if (EVP_CipherFinal_ex(cipher_ctx, nullptr, &enc_unused_len) != 1) {
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return ReturnError("encrypt_EVP_CipherFinal_ex", cipher_ctx);
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}
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enc_len += enc_unused_len;
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if (enc_len != (int)cipher_text->size()) {
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return ReturnError("encrypt_length_mismatch", cipher_ctx);
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}
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if (EVP_CIPHER_CTX_ctrl(cipher_ctx, EVP_CTRL_GCM_GET_TAG,
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sizeof(purse->gmac_tag), purse->gmac_tag) != 1) {
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return ReturnError("EVP_CTRL_GCM_GET_TAG", cipher_ctx);
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}
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EVP_CIPHER_CTX_free(cipher_ctx);
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return absl::OkStatus();
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}
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absl::Status Crypto::Decrypt(const MalignBuffer &cipher_text,
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const CryptoPurse &purse,
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MalignBuffer *plain_text) {
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int dec_len = 0;
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int dec_extra_len = 0;
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EVP_CIPHER_CTX *cipher_ctx = EVP_CIPHER_CTX_new();
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EVP_CipherInit_ex(cipher_ctx, EVP_aes_256_gcm(), NULL, key, purse.i_vec, 0);
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// Make a non-const copy of gmac_tag because that's what EVP_CIPHER_CTX_ctrl
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// requires, even though it won't be modified in this use.
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unsigned char copied_tag[sizeof(purse.gmac_tag)];
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memcpy(copied_tag, purse.gmac_tag, sizeof(purse.gmac_tag));
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if (EVP_CIPHER_CTX_ctrl(cipher_ctx, EVP_CTRL_GCM_SET_TAG, sizeof(copied_tag),
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reinterpret_cast<void *>(copied_tag)) != 1) {
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return ReturnError("EVP_CTRL_GCM_SET_TAG", cipher_ctx);
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}
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if (EVP_CipherUpdate(
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cipher_ctx, reinterpret_cast<unsigned char *>(plain_text->data()),
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&dec_len, reinterpret_cast<const unsigned char *>(cipher_text.data()),
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cipher_text.size()) != 1) {
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return ReturnError("Decryption", cipher_ctx);
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}
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if (EVP_CipherFinal_ex(
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cipher_ctx,
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reinterpret_cast<unsigned char *>(plain_text->data() + dec_len),
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&dec_extra_len) != 1) {
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return ReturnError("decrypt_EVP_CipherFinal_ex", cipher_ctx);
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}
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dec_len += dec_extra_len;
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if (dec_len != (int)plain_text->size()) {
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return ReturnError("decrypt_length_mismatch", cipher_ctx);
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}
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EVP_CIPHER_CTX_free(cipher_ctx);
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return absl::OkStatus();
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}
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absl::Status Crypto::SelfTest() {
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#ifdef USE_BORINGSSL
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if (BORINGSSL_self_test() == 0) {
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return absl::Status(absl::StatusCode::kInternal, "BORINGSSL_self_test");
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}
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#endif
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return absl::OkStatus();
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}
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absl::Status Crypto::ReturnError(absl::string_view message,
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EVP_CIPHER_CTX *cipher_ctx) {
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EVP_CIPHER_CTX_free(cipher_ctx);
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return absl::Status(absl::StatusCode::kInternal, message);
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}
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}; // namespace cpu_check
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