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// Copyright 2015 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "crypto/aead.h"
#include <stddef.h>
#include <stdint.h>
#include <string>
#include "base/strings/string_util.h"
#include "crypto/openssl_util.h"
#include "third_party/boringssl/src/include/openssl/aes.h"
#include "third_party/boringssl/src/include/openssl/evp.h"
namespace crypto {
Aead::Aead(AeadAlgorithm algorithm) {
EnsureOpenSSLInit();
switch (algorithm) {
case AES_128_CTR_HMAC_SHA256:
aead_ = EVP_aead_aes_128_ctr_hmac_sha256();
break;
case AES_256_GCM:
aead_ = EVP_aead_aes_256_gcm();
break;
case AES_256_GCM_SIV:
aead_ = EVP_aead_aes_256_gcm_siv();
break;
case CHACHA20_POLY1305:
aead_ = EVP_aead_chacha20_poly1305();
break;
}
}
Aead::~Aead() = default;
void Aead::Init(base::span<const uint8_t> key) {
DCHECK(!key_);
DCHECK_EQ(KeyLength(), key.size());
key_ = key;
}
static base::span<const uint8_t> ToSpan(std::string_view sp) {
return base::as_bytes(base::make_span(sp));
}
void Aead::Init(const std::string* key) {
Init(ToSpan(*key));
}
std::vector<uint8_t> Aead::Seal(
base::span<const uint8_t> plaintext,
base::span<const uint8_t> nonce,
base::span<const uint8_t> additional_data) const {
const size_t max_output_length =
EVP_AEAD_max_overhead(aead_) + plaintext.size();
CHECK(max_output_length >= plaintext.size());
std::vector<uint8_t> ret;
ret.resize(max_output_length);
size_t output_length;
CHECK(Seal(plaintext, nonce, additional_data, ret.data(), &output_length,
max_output_length));
ret.resize(output_length);
return ret;
}
bool Aead::Seal(std::string_view plaintext,
std::string_view nonce,
std::string_view additional_data,
std::string* ciphertext) const {
const size_t max_output_length =
EVP_AEAD_max_overhead(aead_) + plaintext.size();
CHECK(max_output_length + 1 >= plaintext.size());
uint8_t* out_ptr = reinterpret_cast<uint8_t*>(
base::WriteInto(ciphertext, max_output_length + 1));
size_t output_length;
if (!Seal(ToSpan(plaintext), ToSpan(nonce), ToSpan(additional_data), out_ptr,
&output_length, max_output_length)) {
ciphertext->clear();
return false;
}
ciphertext->resize(output_length);
return true;
}
absl::optional<std::vector<uint8_t>> Aead::Open(
base::span<const uint8_t> ciphertext,
base::span<const uint8_t> nonce,
base::span<const uint8_t> additional_data) const {
const size_t max_output_length = ciphertext.size();
std::vector<uint8_t> ret;
ret.resize(max_output_length);
size_t output_length;
if (!Open(ciphertext, nonce, additional_data, ret.data(), &output_length,
max_output_length)) {
return absl::nullopt;
}
ret.resize(output_length);
return ret;
}
bool Aead::Open(std::string_view ciphertext,
std::string_view nonce,
std::string_view additional_data,
std::string* plaintext) const {
const size_t max_output_length = ciphertext.size();
CHECK(max_output_length + 1 > max_output_length);
uint8_t* out_ptr = reinterpret_cast<uint8_t*>(
base::WriteInto(plaintext, max_output_length + 1));
size_t output_length;
if (!Open(ToSpan(ciphertext), ToSpan(nonce), ToSpan(additional_data), out_ptr,
&output_length, max_output_length)) {
plaintext->clear();
return false;
}
plaintext->resize(output_length);
return true;
}
size_t Aead::KeyLength() const {
return EVP_AEAD_key_length(aead_);
}
size_t Aead::NonceLength() const {
return EVP_AEAD_nonce_length(aead_);
}
bool Aead::Seal(base::span<const uint8_t> plaintext,
base::span<const uint8_t> nonce,
base::span<const uint8_t> additional_data,
uint8_t* out,
size_t* output_length,
size_t max_output_length) const {
DCHECK(key_);
DCHECK_EQ(NonceLength(), nonce.size());
bssl::ScopedEVP_AEAD_CTX ctx;
if (!EVP_AEAD_CTX_init(ctx.get(), aead_, key_->data(), key_->size(),
EVP_AEAD_DEFAULT_TAG_LENGTH, nullptr) ||
!EVP_AEAD_CTX_seal(ctx.get(), out, output_length, max_output_length,
nonce.data(), nonce.size(), plaintext.data(),
plaintext.size(), additional_data.data(),
additional_data.size())) {
return false;
}
DCHECK_LE(*output_length, max_output_length);
return true;
}
bool Aead::Open(base::span<const uint8_t> plaintext,
base::span<const uint8_t> nonce,
base::span<const uint8_t> additional_data,
uint8_t* out,
size_t* output_length,
size_t max_output_length) const {
DCHECK(key_);
DCHECK_EQ(NonceLength(), nonce.size());
bssl::ScopedEVP_AEAD_CTX ctx;
if (!EVP_AEAD_CTX_init(ctx.get(), aead_, key_->data(), key_->size(),
EVP_AEAD_DEFAULT_TAG_LENGTH, nullptr) ||
!EVP_AEAD_CTX_open(ctx.get(), out, output_length, max_output_length,
nonce.data(), nonce.size(), plaintext.data(),
plaintext.size(), additional_data.data(),
additional_data.size())) {
return false;
}
DCHECK_LE(*output_length, max_output_length);
return true;
}
} // namespace crypto
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