162 lines
4.7 KiB
C++
162 lines
4.7 KiB
C++
/*
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Copyright (c) 2007-2018, Un Shyam & Arvid Norberg
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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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#if !defined 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 "libtorrent/config.hpp"
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#include "libtorrent/aux_/disable_warnings_push.hpp"
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#include <boost/multiprecision/cpp_int.hpp>
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#include "libtorrent/aux_/disable_warnings_pop.hpp"
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#include "libtorrent/receive_buffer.hpp"
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#include "libtorrent/sha1_hash.hpp"
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#include "libtorrent/extensions.hpp"
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#include "libtorrent/assert.hpp"
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#include "libtorrent/span.hpp"
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#include "libtorrent/buffer.hpp"
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#include "libtorrent/aux_/array.hpp"
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#include <list>
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#include <array>
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#include <cstdint>
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namespace libtorrent {
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namespace mp = boost::multiprecision;
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using key_t = mp::number<mp::cpp_int_backend<768, 768, mp::unsigned_magnitude, mp::unchecked, void>>;
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TORRENT_EXTRA_EXPORT std::array<char, 96> export_key(key_t const& k);
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// RC4 state from libtomcrypt
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struct rc4 {
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int x;
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int y;
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aux::array<std::uint8_t, 256> buf;
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};
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// TODO: 3 dh_key_exchange should probably move into its own file
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class TORRENT_EXTRA_EXPORT dh_key_exchange
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{
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public:
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dh_key_exchange();
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bool good() const { return true; }
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// Get local public key
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key_t const& get_local_key() const { return m_dh_local_key; }
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// read remote_pubkey, generate and store shared secret in
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// m_dh_shared_secret.
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void compute_secret(std::uint8_t const* remote_pubkey);
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void compute_secret(key_t const& remote_pubkey);
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key_t const& get_secret() const { return m_dh_shared_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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key_t m_dh_local_key;
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key_t m_dh_local_secret;
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key_t m_dh_shared_secret;
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sha1_hash m_xor_mask;
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};
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struct TORRENT_EXTRA_EXPORT encryption_handler
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{
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std::tuple<int, span<span<char const>>>
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encrypt(span<span<char>> iovec);
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int decrypt(crypto_receive_buffer& recv_buffer
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, std::size_t& bytes_transferred);
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bool switch_send_crypto(std::shared_ptr<crypto_plugin> crypto
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, int pending_encryption);
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void switch_recv_crypto(std::shared_ptr<crypto_plugin> crypto
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, crypto_receive_buffer& recv_buffer);
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bool is_send_plaintext() const
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{
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return m_send_barriers.empty() || m_send_barriers.back().next != INT_MAX;
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}
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bool is_recv_plaintext() const
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{
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return m_dec_handler.get() == nullptr;
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}
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private:
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struct barrier
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{
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barrier(std::shared_ptr<crypto_plugin> plugin, int n)
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: enc_handler(plugin), next(n) {}
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std::shared_ptr<crypto_plugin> enc_handler;
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// number of bytes to next barrier
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int next;
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};
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std::list<barrier> m_send_barriers;
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std::shared_ptr<crypto_plugin> m_dec_handler;
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};
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struct TORRENT_EXTRA_EXPORT rc4_handler : crypto_plugin
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{
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public:
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rc4_handler();
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// Input keys must be 20 bytes
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void set_incoming_key(span<char const> key) override;
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void set_outgoing_key(span<char const> key) override;
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std::tuple<int, span<span<char const>>>
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encrypt(span<span<char>> buf) override;
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std::tuple<int, int, int> decrypt(span<span<char>> buf) override;
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private:
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rc4 m_rc4_incoming;
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rc4 m_rc4_outgoing;
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// determines whether or not encryption and decryption is enabled
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bool m_encrypt;
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bool m_decrypt;
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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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