127 lines
3.6 KiB
C++
127 lines
3.6 KiB
C++
/*
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Copyright (c) 2007, Un Shyam
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All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions
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are met:
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* Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in
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the documentation and/or other materials provided with the distribution.
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* Neither the name of the author nor the names of its
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contributors may be used to endorse or promote products derived
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from this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef TORRENT_DISABLE_ENCRYPTION
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#ifndef TORRENT_PE_CRYPTO_HPP_INCLUDED
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#define TORRENT_PE_CRYPTO_HPP_INCLUDED
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#include <openssl/dh.h>
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#include <openssl/engine.h>
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#include <openssl/rc4.h>
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#include "libtorrent/peer_id.hpp" // For sha1_hash
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#include "libtorrent/assert.hpp"
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namespace libtorrent
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{
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class dh_key_exchange
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{
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public:
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dh_key_exchange();
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~dh_key_exchange();
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bool good() const { return m_dh; }
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// Get local public key, always 96 bytes
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char const* get_local_key() const;
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// read remote_pubkey, generate and store shared secret in
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// m_dh_secret.
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int compute_secret(const char* remote_pubkey);
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char const* get_secret() const { return m_dh_secret; }
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sha1_hash const& get_hash_xor_mask() const { return m_xor_mask; }
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private:
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int get_local_key_size() const
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{
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TORRENT_ASSERT(m_dh);
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return BN_num_bytes(m_dh->pub_key);
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}
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DH* m_dh;
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char m_dh_local_key[96];
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char m_dh_secret[96];
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sha1_hash m_xor_mask;
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};
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class RC4_handler // Non copyable
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{
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public:
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// Input longkeys must be 20 bytes
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RC4_handler(const sha1_hash& rc4_local_longkey,
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const sha1_hash& rc4_remote_longkey)
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{
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RC4_set_key(&m_local_key, 20,
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reinterpret_cast<unsigned char const*>(rc4_local_longkey.begin()));
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RC4_set_key(&m_remote_key, 20,
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reinterpret_cast<unsigned char const*>(rc4_remote_longkey.begin()));
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// Discard first 1024 bytes
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char buf[1024];
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encrypt(buf, 1024);
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decrypt(buf, 1024);
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};
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~RC4_handler() {};
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void encrypt(char* pos, int len)
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{
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TORRENT_ASSERT(len >= 0);
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TORRENT_ASSERT(pos);
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RC4(&m_local_key, len, reinterpret_cast<unsigned char const*>(pos),
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reinterpret_cast<unsigned char*>(pos));
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}
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void decrypt(char* pos, int len)
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{
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TORRENT_ASSERT(len >= 0);
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TORRENT_ASSERT(pos);
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RC4(&m_remote_key, len, reinterpret_cast<unsigned char const*>(pos),
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reinterpret_cast<unsigned char*>(pos));
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}
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private:
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RC4_KEY m_local_key; // Key to encrypt outgoing data
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RC4_KEY m_remote_key; // Key to decrypt incoming data
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};
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} // namespace libtorrent
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#endif // TORRENT_PE_CRYPTO_HPP_INCLUDED
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#endif // TORRENT_DISABLE_ENCRYPTION
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