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/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/**
* Copyright (c) 2013-2016 Regents of the University of California.
*
* This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
*
* ndn-cxx library is free software: you can redistribute it and/or modify it under the
* terms of the GNU Lesser General Public License as published by the Free Software
* Foundation, either version 3 of the License, or (at your option) any later version.
*
* ndn-cxx library is distributed in the hope that it will be useful, but WITHOUT ANY
* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
* PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
*
* You should have received copies of the GNU General Public License and GNU Lesser
* General Public License along with ndn-cxx, e.g., in COPYING.md file. If not, see
* <http://www.gnu.org/licenses/>.
*
* See AUTHORS.md for complete list of ndn-cxx authors and contributors.
*/
#include "block-cipher.hpp"
#include "../detail/openssl.hpp"
#include <boost/lexical_cast.hpp>
namespace ndn {
namespace security {
namespace transform {
class BlockCipher::Impl
{
public:
Impl()
: m_cipher(BIO_new(BIO_f_cipher()))
, m_sink(BIO_new(BIO_s_mem()))
{
BIO_push(m_cipher, m_sink);
}
~Impl()
{
BIO_free_all(m_cipher);
}
public:
BIO* m_cipher;
BIO* m_sink; // BIO_f_cipher alone does not work without a sink
};
BlockCipher::BlockCipher(BlockCipherAlgorithm algo, CipherOperator op,
const uint8_t* key, size_t keyLen,
const uint8_t* iv, size_t ivLen)
: m_impl(new Impl)
{
switch (algo) {
case BlockCipherAlgorithm::AES_CBC:
initializeAesCbc(key, keyLen, iv, ivLen, op);
break;
default:
BOOST_THROW_EXCEPTION(Error(getIndex(), "Cipher algorithm " +
boost::lexical_cast<std::string>(algo) + " is not supported"));
}
}
void
BlockCipher::preTransform()
{
fillOutputBuffer();
}
size_t
BlockCipher::convert(const uint8_t* data, size_t dataLen)
{
if (dataLen == 0)
return 0;
int wLen = BIO_write(m_impl->m_cipher, data, dataLen);
if (wLen <= 0) { // fail to write data
if (!BIO_should_retry(m_impl->m_cipher)) {
// we haven't written everything but some error happens, and we cannot retry
BOOST_THROW_EXCEPTION(Error(getIndex(), "Failed to accept more input"));
}
return 0;
}
else { // update number of bytes written
fillOutputBuffer();
return wLen;
}
}
void
BlockCipher::finalize()
{
if (BIO_flush(m_impl->m_cipher) != 1)
BOOST_THROW_EXCEPTION(Error(getIndex(), "Failed to flush"));
while (!isConverterEmpty()) {
fillOutputBuffer();
while (!isOutputBufferEmpty()) {
flushOutputBuffer();
}
}
}
void
BlockCipher::fillOutputBuffer()
{
int nRead = BIO_pending(m_impl->m_sink);
if (nRead <= 0)
return;
// there is something to read from BIO
auto buffer = make_unique<OBuffer>(nRead);
int rLen = BIO_read(m_impl->m_sink, &(*buffer)[0], nRead);
if (rLen < 0)
return;
if (rLen < nRead)
buffer->erase(buffer->begin() + rLen, buffer->end());
setOutputBuffer(std::move(buffer));
}
bool
BlockCipher::isConverterEmpty() const
{
return (BIO_pending(m_impl->m_sink) <= 0);
}
void
BlockCipher::initializeAesCbc(const uint8_t* key, size_t keyLen,
const uint8_t* iv, size_t ivLen,
CipherOperator op)
{
if (keyLen != ivLen)
BOOST_THROW_EXCEPTION(Error(getIndex(), "Key length must be the same as IV length"));
const EVP_CIPHER* cipherType = nullptr;
switch (keyLen) {
case 16:
cipherType = EVP_aes_128_cbc();
break;
case 24:
cipherType = EVP_aes_192_cbc();
break;
case 32:
cipherType = EVP_aes_256_cbc();
break;
default:
BOOST_THROW_EXCEPTION(Error(getIndex(), "Key length is not supported"));
}
BIO_set_cipher(m_impl->m_cipher, cipherType, key, iv, static_cast<int>(op));
}
unique_ptr<Transform>
blockCipher(BlockCipherAlgorithm algo, CipherOperator op,
const uint8_t* key, size_t keyLen,
const uint8_t* iv, size_t ivLen)
{
return make_unique<BlockCipher>(algo, op, key, keyLen, iv, ivLen);
}
} // namespace transform
} // namespace security
} // namespace ndn