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// Copyright (c) 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "net/third_party/quiche/src/quic/core/crypto/aead_base_encrypter.h"
#include "absl/base/macros.h"
#include "absl/strings/string_view.h"
#include "third_party/boringssl/src/include/openssl/crypto.h"
#include "third_party/boringssl/src/include/openssl/err.h"
#include "third_party/boringssl/src/include/openssl/evp.h"
#include "net/third_party/quiche/src/quic/core/quic_utils.h"
#include "net/third_party/quiche/src/quic/platform/api/quic_bug_tracker.h"
#include "net/third_party/quiche/src/quic/platform/api/quic_logging.h"
namespace quic {
namespace {
// In debug builds only, log OpenSSL error stack. Then clear OpenSSL error
// stack.
void DLogOpenSslErrors() {
#ifdef NDEBUG
while (ERR_get_error()) {
}
#else
while (unsigned long error = ERR_get_error()) {
char buf[120];
ERR_error_string_n(error, buf, ABSL_ARRAYSIZE(buf));
QUIC_DLOG(ERROR) << "OpenSSL error: " << buf;
}
#endif
}
const EVP_AEAD* InitAndCall(const EVP_AEAD* (*aead_getter)()) {
// Ensure BoringSSL is initialized before calling |aead_getter|. In Chromium,
// the static initializer is disabled.
CRYPTO_library_init();
return aead_getter();
}
} // namespace
AeadBaseEncrypter::AeadBaseEncrypter(const EVP_AEAD* (*aead_getter)(),
size_t key_size,
size_t auth_tag_size,
size_t nonce_size,
bool use_ietf_nonce_construction)
: aead_alg_(InitAndCall(aead_getter)),
key_size_(key_size),
auth_tag_size_(auth_tag_size),
nonce_size_(nonce_size),
use_ietf_nonce_construction_(use_ietf_nonce_construction) {
DCHECK_LE(key_size_, sizeof(key_));
DCHECK_LE(nonce_size_, sizeof(iv_));
DCHECK_GE(kMaxNonceSize, nonce_size_);
}
AeadBaseEncrypter::~AeadBaseEncrypter() {}
bool AeadBaseEncrypter::SetKey(absl::string_view key) {
DCHECK_EQ(key.size(), key_size_);
if (key.size() != key_size_) {
return false;
}
memcpy(key_, key.data(), key.size());
EVP_AEAD_CTX_cleanup(ctx_.get());
if (!EVP_AEAD_CTX_init(ctx_.get(), aead_alg_, key_, key_size_, auth_tag_size_,
nullptr)) {
DLogOpenSslErrors();
return false;
}
return true;
}
bool AeadBaseEncrypter::SetNoncePrefix(absl::string_view nonce_prefix) {
if (use_ietf_nonce_construction_) {
QUIC_BUG << "Attempted to set nonce prefix on IETF QUIC crypter";
return false;
}
DCHECK_EQ(nonce_prefix.size(), nonce_size_ - sizeof(QuicPacketNumber));
if (nonce_prefix.size() != nonce_size_ - sizeof(QuicPacketNumber)) {
return false;
}
memcpy(iv_, nonce_prefix.data(), nonce_prefix.size());
return true;
}
bool AeadBaseEncrypter::SetIV(absl::string_view iv) {
if (!use_ietf_nonce_construction_) {
QUIC_BUG << "Attempted to set IV on Google QUIC crypter";
return false;
}
DCHECK_EQ(iv.size(), nonce_size_);
if (iv.size() != nonce_size_) {
return false;
}
memcpy(iv_, iv.data(), iv.size());
return true;
}
bool AeadBaseEncrypter::Encrypt(absl::string_view nonce,
absl::string_view associated_data,
absl::string_view plaintext,
unsigned char* output) {
DCHECK_EQ(nonce.size(), nonce_size_);
size_t ciphertext_len;
if (!EVP_AEAD_CTX_seal(
ctx_.get(), output, &ciphertext_len,
plaintext.size() + auth_tag_size_,
reinterpret_cast<const uint8_t*>(nonce.data()), nonce.size(),
reinterpret_cast<const uint8_t*>(plaintext.data()), plaintext.size(),
reinterpret_cast<const uint8_t*>(associated_data.data()),
associated_data.size())) {
DLogOpenSslErrors();
return false;
}
return true;
}
bool AeadBaseEncrypter::EncryptPacket(uint64_t packet_number,
absl::string_view associated_data,
absl::string_view plaintext,
char* output,
size_t* output_length,
size_t max_output_length) {
size_t ciphertext_size = GetCiphertextSize(plaintext.length());
if (max_output_length < ciphertext_size) {
return false;
}
// TODO(ianswett): Introduce a check to ensure that we don't encrypt with the
// same packet number twice.
alignas(4) char nonce_buffer[kMaxNonceSize];
memcpy(nonce_buffer, iv_, nonce_size_);
size_t prefix_len = nonce_size_ - sizeof(packet_number);
if (use_ietf_nonce_construction_) {
for (size_t i = 0; i < sizeof(packet_number); ++i) {
nonce_buffer[prefix_len + i] ^=
(packet_number >> ((sizeof(packet_number) - i - 1) * 8)) & 0xff;
}
} else {
memcpy(nonce_buffer + prefix_len, &packet_number, sizeof(packet_number));
}
if (!Encrypt(absl::string_view(nonce_buffer, nonce_size_), associated_data,
plaintext, reinterpret_cast<unsigned char*>(output))) {
return false;
}
*output_length = ciphertext_size;
return true;
}
size_t AeadBaseEncrypter::GetKeySize() const {
return key_size_;
}
size_t AeadBaseEncrypter::GetNoncePrefixSize() const {
return nonce_size_ - sizeof(QuicPacketNumber);
}
size_t AeadBaseEncrypter::GetIVSize() const {
return nonce_size_;
}
size_t AeadBaseEncrypter::GetMaxPlaintextSize(size_t ciphertext_size) const {
return ciphertext_size - std::min(ciphertext_size, auth_tag_size_);
}
size_t AeadBaseEncrypter::GetCiphertextSize(size_t plaintext_size) const {
return plaintext_size + auth_tag_size_;
}
absl::string_view AeadBaseEncrypter::GetKey() const {
return absl::string_view(reinterpret_cast<const char*>(key_), key_size_);
}
absl::string_view AeadBaseEncrypter::GetNoncePrefix() const {
return absl::string_view(reinterpret_cast<const char*>(iv_),
GetNoncePrefixSize());
}
} // namespace quic
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