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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/aead_base_encrypter.h"
#include <openssl/err.h>
#include <openssl/evp.h>
#include <string.h>
#include "base/memory/scoped_ptr.h"
using base::StringPiece;
namespace net {
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, arraysize(buf));
DLOG(ERROR) << "OpenSSL error: " << buf;
}
#endif
}
} // namespace
AeadBaseEncrypter::AeadBaseEncrypter(const EVP_AEAD* aead_alg,
size_t key_size,
size_t auth_tag_size,
size_t nonce_prefix_size)
: aead_alg_(aead_alg),
key_size_(key_size),
auth_tag_size_(auth_tag_size),
nonce_prefix_size_(nonce_prefix_size) {
DCHECK_LE(key_size_, sizeof(key_));
DCHECK_LE(nonce_prefix_size_, sizeof(nonce_prefix_));
}
AeadBaseEncrypter::~AeadBaseEncrypter() {}
bool AeadBaseEncrypter::SetKey(StringPiece 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_, NULL)) {
DLogOpenSslErrors();
return false;
}
return true;
}
bool AeadBaseEncrypter::SetNoncePrefix(StringPiece nonce_prefix) {
DCHECK_EQ(nonce_prefix.size(), nonce_prefix_size_);
if (nonce_prefix.size() != nonce_prefix_size_) {
return false;
}
memcpy(nonce_prefix_, nonce_prefix.data(), nonce_prefix.size());
return true;
}
bool AeadBaseEncrypter::Encrypt(StringPiece nonce,
StringPiece associated_data,
StringPiece plaintext,
unsigned char* output) {
if (nonce.size() != nonce_prefix_size_ + sizeof(QuicPacketSequenceNumber)) {
return false;
}
ssize_t len = EVP_AEAD_CTX_seal(
ctx_.get(), output, 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());
if (len < 0) {
DLogOpenSslErrors();
return false;
}
return true;
}
QuicData* AeadBaseEncrypter::EncryptPacket(
QuicPacketSequenceNumber sequence_number,
StringPiece associated_data,
StringPiece plaintext) {
size_t ciphertext_size = GetCiphertextSize(plaintext.length());
scoped_ptr<char[]> ciphertext(new char[ciphertext_size]);
// TODO(ianswett): Introduce a check to ensure that we don't encrypt with the
// same sequence number twice.
uint8 nonce[sizeof(nonce_prefix_) + sizeof(sequence_number)];
const size_t nonce_size = nonce_prefix_size_ + sizeof(sequence_number);
DCHECK_LE(nonce_size, sizeof(nonce));
memcpy(nonce, nonce_prefix_, nonce_prefix_size_);
memcpy(nonce + nonce_prefix_size_, &sequence_number, sizeof(sequence_number));
if (!Encrypt(StringPiece(reinterpret_cast<char*>(nonce), nonce_size),
associated_data, plaintext,
reinterpret_cast<unsigned char*>(ciphertext.get()))) {
return NULL;
}
return new QuicData(ciphertext.release(), ciphertext_size, true);
}
size_t AeadBaseEncrypter::GetKeySize() const { return key_size_; }
size_t AeadBaseEncrypter::GetNoncePrefixSize() const {
return nonce_prefix_size_;
}
size_t AeadBaseEncrypter::GetMaxPlaintextSize(size_t ciphertext_size) const {
return ciphertext_size - auth_tag_size_;
}
size_t AeadBaseEncrypter::GetCiphertextSize(size_t plaintext_size) const {
return plaintext_size + auth_tag_size_;
}
StringPiece AeadBaseEncrypter::GetKey() const {
return StringPiece(reinterpret_cast<const char*>(key_), key_size_);
}
StringPiece AeadBaseEncrypter::GetNoncePrefix() const {
if (nonce_prefix_size_ == 0) {
return StringPiece();
}
return StringPiece(reinterpret_cast<const char*>(nonce_prefix_),
nonce_prefix_size_);
}
} // namespace net
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