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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/quic/crypto/p256_key_exchange.h"
#include <openssl/ec.h>
#include <openssl/ecdh.h>
#include <openssl/evp.h>
#include "base/logging.h"
namespace net {
P256KeyExchange::P256KeyExchange(EC_KEY* private_key, const uint8* public_key)
: private_key_(private_key) {
memcpy(public_key_, public_key, sizeof(public_key_));
}
P256KeyExchange::~P256KeyExchange() {
}
// static
P256KeyExchange* P256KeyExchange::New(base::StringPiece key) {
if (key.empty()) {
DLOG(INFO) << "Private key is empty";
return NULL;
}
const uint8* keyp = reinterpret_cast<const uint8*>(key.data());
crypto::ScopedOpenSSL<EC_KEY, EC_KEY_free> private_key(
d2i_ECPrivateKey(NULL, &keyp, key.size()));
if (!private_key.get() || !EC_KEY_check_key(private_key.get())) {
DLOG(INFO) << "Private key is invalid";
return NULL;
}
uint8 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),
NULL) != sizeof(public_key)) {
DLOG(INFO) << "Can't get public key";
return NULL;
}
return new P256KeyExchange(private_key.release(), public_key);
}
// static
std::string P256KeyExchange::NewPrivateKey() {
crypto::ScopedOpenSSL<EC_KEY, EC_KEY_free> key(
EC_KEY_new_by_curve_name(NID_X9_62_prime256v1));
if (!key.get() || !EC_KEY_generate_key(key.get())) {
DLOG(INFO) << "Can't generate a new private key";
return std::string();
}
int key_len = i2d_ECPrivateKey(key.get(), NULL);
if (key_len <= 0) {
DLOG(INFO) << "Can't convert private key to string";
return std::string();
}
scoped_ptr<uint8[]> private_key(new uint8[key_len]);
uint8* keyp = private_key.get();
if (!i2d_ECPrivateKey(key.get(), &keyp)) {
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::CalculateSharedKey(
const base::StringPiece& peer_public_value,
std::string* out_result) const {
if (peer_public_value.size() != kUncompressedP256PointBytes) {
DLOG(INFO) << "Peer public value is invalid";
return false;
}
crypto::ScopedOpenSSL<EC_POINT, EC_POINT_free> 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*>(peer_public_value.data()),
peer_public_value.size(),
NULL)) {
DLOG(INFO) << "Can't convert peer public value to curve point";
return false;
}
uint8 result[kP256FieldBytes];
if (ECDH_compute_key(
result,
sizeof(result),
point.get(),
private_key_.get(),
NULL) != sizeof(result)) {
DLOG(INFO) << "Can't compute ECDH shared key";
return false;
}
out_result->assign(reinterpret_cast<char*>(result), sizeof(result));
return true;
}
base::StringPiece P256KeyExchange::public_value() const {
return base::StringPiece(reinterpret_cast<const char*>(public_key_),
sizeof(public_key_));
}
CryptoTag P256KeyExchange::tag() const {
return kP256;
}
} // namespace net
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