123 lines
4.2 KiB
C++
123 lines
4.2 KiB
C++
/*
|
|
|
|
Copyright (c) 2007, Un Shyam
|
|
All rights reserved.
|
|
|
|
Redistribution and use in source and binary forms, with or without
|
|
modification, are permitted provided that the following conditions
|
|
are met:
|
|
|
|
* Redistributions of source code must retain the above copyright
|
|
notice, this list of conditions and the following disclaimer.
|
|
* Redistributions in binary form must reproduce the above copyright
|
|
notice, this list of conditions and the following disclaimer in
|
|
the documentation and/or other materials provided with the distribution.
|
|
* Neither the name of the author nor the names of its
|
|
contributors may be used to endorse or promote products derived
|
|
from this software without specific prior written permission.
|
|
|
|
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
|
|
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
|
|
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
|
|
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
|
|
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
|
|
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
|
|
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
|
|
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
|
POSSIBILITY OF SUCH DAMAGE.
|
|
|
|
*/
|
|
|
|
#ifndef TORRENT_DISABLE_ENCRYPTION
|
|
|
|
#include <cassert>
|
|
#include <algorithm>
|
|
|
|
#include <openssl/dh.h>
|
|
#include <openssl/engine.h>
|
|
|
|
#include "libtorrent/pe_crypto.hpp"
|
|
|
|
namespace libtorrent {
|
|
|
|
|
|
// Set the prime P and the generator, generate local public key
|
|
DH_key_exchange::DH_key_exchange ()
|
|
{
|
|
m_DH = DH_new ();
|
|
|
|
m_DH->p = BN_bin2bn (m_dh_prime, sizeof(m_dh_prime), NULL);
|
|
m_DH->g = BN_bin2bn (m_dh_generator, sizeof(m_dh_generator), NULL);
|
|
|
|
assert (sizeof(m_dh_prime) == DH_size(m_DH));
|
|
|
|
DH_generate_key (m_DH); // TODO Check != 0
|
|
|
|
assert (m_DH->pub_key);
|
|
|
|
// DH can generate key sizes that are smaller than the size of
|
|
// P with exponentially decreasing probability, in which case
|
|
// the msb's of m_dh_local_key need to be zeroed
|
|
// appropriately.
|
|
int key_size = get_local_key_size();
|
|
int len_dh = sizeof(m_dh_prime); // must equal DH_size(m_DH)
|
|
if (key_size != len_dh)
|
|
{
|
|
assert(key_size > 0 && key_size < len_dh);
|
|
|
|
int pad_zero_size = len_dh - key_size;
|
|
std::fill(m_dh_local_key, m_dh_local_key + pad_zero_size, 0);
|
|
BN_bn2bin(m_DH->pub_key, (unsigned char*)m_dh_local_key + pad_zero_size);
|
|
}
|
|
else
|
|
BN_bn2bin(m_DH->pub_key, (unsigned char*)m_dh_local_key); // TODO Check return value
|
|
}
|
|
|
|
DH_key_exchange::~DH_key_exchange ()
|
|
{
|
|
assert (m_DH);
|
|
DH_free (m_DH);
|
|
}
|
|
|
|
char const* DH_key_exchange::get_local_key () const
|
|
{
|
|
return m_dh_local_key;
|
|
}
|
|
|
|
|
|
// compute shared secret given remote public key
|
|
void DH_key_exchange::compute_secret (char const* remote_pubkey)
|
|
{
|
|
assert (remote_pubkey);
|
|
BIGNUM* bn_remote_pubkey = BN_bin2bn ((unsigned char*)remote_pubkey, 96, NULL);
|
|
|
|
int ret =
|
|
DH_compute_key ( (unsigned char*)m_dh_secret, bn_remote_pubkey, m_DH); // TODO Check for errors
|
|
|
|
BN_free (bn_remote_pubkey);
|
|
}
|
|
|
|
char const* DH_key_exchange::get_secret () const
|
|
{
|
|
return m_dh_secret;
|
|
}
|
|
|
|
const unsigned char DH_key_exchange::m_dh_prime[96] = {
|
|
0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xC9, 0x0F, 0xDA, 0xA2,
|
|
0x21, 0x68, 0xC2, 0x34, 0xC4, 0xC6, 0x62, 0x8B, 0x80, 0xDC, 0x1C, 0xD1,
|
|
0x29, 0x02, 0x4E, 0x08, 0x8A, 0x67, 0xCC, 0x74, 0x02, 0x0B, 0xBE, 0xA6,
|
|
0x3B, 0x13, 0x9B, 0x22, 0x51, 0x4A, 0x08, 0x79, 0x8E, 0x34, 0x04, 0xDD,
|
|
0xEF, 0x95, 0x19, 0xB3, 0xCD, 0x3A, 0x43, 0x1B, 0x30, 0x2B, 0x0A, 0x6D,
|
|
0xF2, 0x5F, 0x14, 0x37, 0x4F, 0xE1, 0x35, 0x6D, 0x6D, 0x51, 0xC2, 0x45,
|
|
0xE4, 0x85, 0xB5, 0x76, 0x62, 0x5E, 0x7E, 0xC6, 0xF4, 0x4C, 0x42, 0xE9,
|
|
0xA6, 0x3A, 0x36, 0x21, 0x00, 0x00, 0x00, 0x00, 0x00, 0x09, 0x05, 0x63
|
|
};
|
|
|
|
const unsigned char DH_key_exchange::m_dh_generator[1] = { 2 };
|
|
|
|
} // namespace libtorrent
|
|
|
|
#endif // #ifndef TORRENT_DISABLE_ENCRYPTION
|