blob: 5340b41107cba175709dac4052dc48c12d61d95b [file] [log] [blame]
// 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 "quiche/quic/core/crypto/curve25519_key_exchange.h"
#include <cstdint>
#include <cstring>
#include <string>
#include "absl/memory/memory.h"
#include "absl/strings/string_view.h"
#include "openssl/curve25519.h"
#include "quiche/quic/core/crypto/quic_random.h"
#include "quiche/quic/platform/api/quic_bug_tracker.h"
namespace quic {
Curve25519KeyExchange::Curve25519KeyExchange() {}
Curve25519KeyExchange::~Curve25519KeyExchange() {}
// static
std::unique_ptr<Curve25519KeyExchange> Curve25519KeyExchange::New(
QuicRandom* rand) {
std::unique_ptr<Curve25519KeyExchange> result =
New(Curve25519KeyExchange::NewPrivateKey(rand));
QUIC_BUG_IF(quic_bug_12891_1, result == nullptr);
return result;
}
// static
std::unique_ptr<Curve25519KeyExchange> Curve25519KeyExchange::New(
absl::string_view private_key) {
// We don't want to #include the BoringSSL headers in the public header file,
// so we use literals for the sizes of private_key_ and public_key_. Here we
// assert that those values are equal to the values from the BoringSSL
// header.
static_assert(
sizeof(Curve25519KeyExchange::private_key_) == X25519_PRIVATE_KEY_LEN,
"header out of sync");
static_assert(
sizeof(Curve25519KeyExchange::public_key_) == X25519_PUBLIC_VALUE_LEN,
"header out of sync");
if (private_key.size() != X25519_PRIVATE_KEY_LEN) {
return nullptr;
}
// Use absl::WrapUnique(new) instead of std::make_unique because
// Curve25519KeyExchange has a private constructor.
auto ka = absl::WrapUnique(new Curve25519KeyExchange);
memcpy(ka->private_key_, private_key.data(), X25519_PRIVATE_KEY_LEN);
X25519_public_from_private(ka->public_key_, ka->private_key_);
return ka;
}
// static
std::string Curve25519KeyExchange::NewPrivateKey(QuicRandom* rand) {
uint8_t private_key[X25519_PRIVATE_KEY_LEN];
rand->RandBytes(private_key, sizeof(private_key));
return std::string(reinterpret_cast<char*>(private_key), sizeof(private_key));
}
bool Curve25519KeyExchange::CalculateSharedKeySync(
absl::string_view peer_public_value, std::string* shared_key) const {
if (peer_public_value.size() != X25519_PUBLIC_VALUE_LEN) {
return false;
}
uint8_t result[X25519_PUBLIC_VALUE_LEN];
if (!X25519(result, private_key_,
reinterpret_cast<const uint8_t*>(peer_public_value.data()))) {
return false;
}
shared_key->assign(reinterpret_cast<char*>(result), sizeof(result));
return true;
}
absl::string_view Curve25519KeyExchange::public_value() const {
return absl::string_view(reinterpret_cast<const char*>(public_key_),
sizeof(public_key_));
}
} // namespace quic