| // 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 "quic/core/crypto/p256_key_exchange.h" |
| |
| #include <cstdint> |
| #include <cstring> |
| #include <memory> |
| #include <string> |
| #include <utility> |
| |
| #include "absl/memory/memory.h" |
| #include "absl/strings/string_view.h" |
| #include "third_party/boringssl/src/include/openssl/ec.h" |
| #include "third_party/boringssl/src/include/openssl/ecdh.h" |
| #include "third_party/boringssl/src/include/openssl/err.h" |
| #include "third_party/boringssl/src/include/openssl/evp.h" |
| #include "quic/platform/api/quic_logging.h" |
| |
| namespace quic { |
| |
| P256KeyExchange::P256KeyExchange(bssl::UniquePtr<EC_KEY> private_key, |
| const uint8_t* public_key) |
| : private_key_(std::move(private_key)) { |
| memcpy(public_key_, public_key, sizeof(public_key_)); |
| } |
| |
| P256KeyExchange::~P256KeyExchange() {} |
| |
| // static |
| std::unique_ptr<P256KeyExchange> P256KeyExchange::New() { |
| return New(P256KeyExchange::NewPrivateKey()); |
| } |
| |
| // static |
| std::unique_ptr<P256KeyExchange> P256KeyExchange::New(absl::string_view key) { |
| if (key.empty()) { |
| QUIC_DLOG(INFO) << "Private key is empty"; |
| return nullptr; |
| } |
| |
| const uint8_t* keyp = reinterpret_cast<const uint8_t*>(key.data()); |
| bssl::UniquePtr<EC_KEY> private_key( |
| d2i_ECPrivateKey(nullptr, &keyp, key.size())); |
| if (!private_key.get() || !EC_KEY_check_key(private_key.get())) { |
| QUIC_DLOG(INFO) << "Private key is invalid."; |
| return nullptr; |
| } |
| |
| uint8_t public_key[kUncompressedP256PointBytes]; |
| if (EC_POINT_point2oct(EC_KEY_get0_group(private_key.get()), |
| EC_KEY_get0_public_key(private_key.get()), |
| POINT_CONVERSION_UNCOMPRESSED, public_key, |
| sizeof(public_key), nullptr) != sizeof(public_key)) { |
| QUIC_DLOG(INFO) << "Can't get public key."; |
| return nullptr; |
| } |
| |
| return absl::WrapUnique( |
| new P256KeyExchange(std::move(private_key), public_key)); |
| } |
| |
| // static |
| std::string P256KeyExchange::NewPrivateKey() { |
| bssl::UniquePtr<EC_KEY> key(EC_KEY_new_by_curve_name(NID_X9_62_prime256v1)); |
| if (!key.get() || !EC_KEY_generate_key(key.get())) { |
| QUIC_DLOG(INFO) << "Can't generate a new private key."; |
| return std::string(); |
| } |
| |
| int key_len = i2d_ECPrivateKey(key.get(), nullptr); |
| if (key_len <= 0) { |
| QUIC_DLOG(INFO) << "Can't convert private key to string"; |
| return std::string(); |
| } |
| std::unique_ptr<uint8_t[]> private_key(new uint8_t[key_len]); |
| uint8_t* keyp = private_key.get(); |
| if (!i2d_ECPrivateKey(key.get(), &keyp)) { |
| QUIC_DLOG(INFO) << "Can't convert private key to string."; |
| return std::string(); |
| } |
| return std::string(reinterpret_cast<char*>(private_key.get()), key_len); |
| } |
| |
| bool P256KeyExchange::CalculateSharedKeySync( |
| absl::string_view peer_public_value, |
| std::string* shared_key) const { |
| if (peer_public_value.size() != kUncompressedP256PointBytes) { |
| QUIC_DLOG(INFO) << "Peer public value is invalid"; |
| return false; |
| } |
| |
| bssl::UniquePtr<EC_POINT> point( |
| EC_POINT_new(EC_KEY_get0_group(private_key_.get()))); |
| if (!point.get() || |
| !EC_POINT_oct2point(/* also test if point is on curve */ |
| EC_KEY_get0_group(private_key_.get()), point.get(), |
| reinterpret_cast<const uint8_t*>( |
| peer_public_value.data()), |
| peer_public_value.size(), nullptr)) { |
| QUIC_DLOG(INFO) << "Can't convert peer public value to curve point."; |
| return false; |
| } |
| |
| uint8_t result[kP256FieldBytes]; |
| if (ECDH_compute_key(result, sizeof(result), point.get(), private_key_.get(), |
| nullptr) != sizeof(result)) { |
| QUIC_DLOG(INFO) << "Can't compute ECDH shared key."; |
| return false; |
| } |
| |
| shared_key->assign(reinterpret_cast<char*>(result), sizeof(result)); |
| return true; |
| } |
| |
| absl::string_view P256KeyExchange::public_value() const { |
| return absl::string_view(reinterpret_cast<const char*>(public_key_), |
| sizeof(public_key_)); |
| } |
| |
| } // namespace quic |