diff options
Diffstat (limited to 'src/net/socks.cpp')
| -rw-r--r-- | src/net/socks.cpp | 308 |
1 files changed, 308 insertions, 0 deletions
diff --git a/src/net/socks.cpp b/src/net/socks.cpp new file mode 100644 index 000000000..f31efc8c1 --- /dev/null +++ b/src/net/socks.cpp @@ -0,0 +1,308 @@ +// Copyright (c) 2018, The Monero Project +// +// All rights reserved. +// +// Redistribution and use in source and binary forms, with or without modification, are +// permitted provided that the following conditions are met: +// +// 1. Redistributions of source code must retain the above copyright notice, this list of +// conditions and the following disclaimer. +// +// 2. 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. +// +// 3. Neither the name of the copyright holder 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 HOLDER 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. + +#include "socks.h" + +#include <algorithm> +#include <boost/asio/buffer.hpp> +#include <boost/asio/read.hpp> +#include <boost/asio/write.hpp> +#include <boost/endian/arithmetic.hpp> +#include <boost/endian/conversion.hpp> +#include <cstring> +#include <limits> +#include <string> + +#include "net/net_utils_base.h" +#include "net/tor_address.h" + +namespace net +{ +namespace socks +{ + namespace + { + constexpr const unsigned v4_reply_size = 8; + constexpr const std::uint8_t v4_connect_command = 1; + constexpr const std::uint8_t v4tor_resolve_command = 0xf0; + constexpr const std::uint8_t v4_request_granted = 90; + + struct v4_header + { + std::uint8_t version; + std::uint8_t command_code; + boost::endian::big_uint16_t port; + boost::endian::big_uint32_t ip; + }; + + std::size_t write_domain_header(epee::span<std::uint8_t> out, const std::uint8_t command, const std::uint16_t port, const boost::string_ref domain) + { + if (std::numeric_limits<std::size_t>::max() - sizeof(v4_header) - 2 < domain.size()) + return 0; + + const std::size_t buf_size = sizeof(v4_header) + domain.size() + 2; + if (out.size() < buf_size) + return 0; + + // version 4, 1 indicates invalid ip for domain extension + const v4_header temp{4, command, port, std::uint32_t(1)}; + std::memcpy(out.data(), std::addressof(temp), sizeof(temp)); + out.remove_prefix(sizeof(temp)); + + *(out.data()) = 0; + out.remove_prefix(1); + + std::memcpy(out.data(), domain.data(), domain.size()); + out.remove_prefix(domain.size()); + + *(out.data()) = 0; + return buf_size; + } + + struct socks_category : boost::system::error_category + { + explicit socks_category() noexcept + : boost::system::error_category() + {} + + const char* name() const noexcept override + { + return "net::socks::error_category"; + } + + virtual std::string message(int value) const override + { + switch (socks::error(value)) + { + case socks::error::rejected: + return "Socks request rejected or failed"; + case socks::error::identd_connection: + return "Socks request rejected because server cannot connect to identd on the client"; + case socks::error::identd_user: + return "Socks request rejected because the client program and identd report different user-ids"; + + case socks::error::bad_read: + return "Socks boost::async_read read fewer bytes than expected"; + case socks::error::bad_write: + return "Socks boost::async_write wrote fewer bytes than expected"; + case socks::error::unexpected_version: + return "Socks server returned unexpected version in reply"; + + default: + break; + } + return "Unknown net::socks::error"; + } + + boost::system::error_condition default_error_condition(int value) const noexcept override + { + switch (socks::error(value)) + { + case socks::error::bad_read: + case socks::error::bad_write: + return boost::system::errc::io_error; + case socks::error::unexpected_version: + return boost::system::errc::protocol_error; + default: + break; + }; + if (1 <= value && value <= 256) + return boost::system::errc::protocol_error; + + return boost::system::error_condition{value, *this}; + } + }; + } + + const boost::system::error_category& error_category() noexcept + { + static const socks_category instance{}; + return instance; + } + + struct client::completed + { + std::shared_ptr<client> self_; + + void operator()(const boost::system::error_code error, const std::size_t bytes) const + { + static_assert(1 < sizeof(self_->buffer_), "buffer too small for v4 response"); + + if (self_) + { + client& self = *self_; + self.buffer_size_ = std::min(bytes, sizeof(self.buffer_)); + + if (error) + self.done(error, std::move(self_)); + else if (self.buffer().size() < sizeof(v4_header)) + self.done(socks::error::bad_read, std::move(self_)); + else if (self.buffer_[0] != 0) // response version + self.done(socks::error::unexpected_version, std::move(self_)); + else if (self.buffer_[1] != v4_request_granted) + self.done(socks::error(int(self.buffer_[1]) + 1), std::move(self_)); + else + self.done(boost::system::error_code{}, std::move(self_)); + } + } + }; + + struct client::read + { + std::shared_ptr<client> self_; + + static boost::asio::mutable_buffers_1 get_buffer(client& self) noexcept + { + static_assert(sizeof(v4_header) <= sizeof(self.buffer_), "buffer too small for v4 response"); + return boost::asio::buffer(self.buffer_, sizeof(v4_header)); + } + + void operator()(const boost::system::error_code error, const std::size_t bytes) + { + if (self_) + { + client& self = *self_; + if (error) + self.done(error, std::move(self_)); + else if (bytes < self.buffer().size()) + self.done(socks::error::bad_write, std::move(self_)); + else + boost::asio::async_read(self.proxy_, get_buffer(self), completed{std::move(self_)}); + } + } + }; + + struct client::write + { + std::shared_ptr<client> self_; + + static boost::asio::const_buffers_1 get_buffer(client const& self) noexcept + { + return boost::asio::buffer(self.buffer_, self.buffer_size_); + } + + void operator()(const boost::system::error_code error) + { + if (self_) + { + client& self = *self_; + if (error) + self.done(error, std::move(self_)); + else + boost::asio::async_write(self.proxy_, get_buffer(self), read{std::move(self_)}); + } + } + }; + + client::client(stream_type::socket&& proxy, socks::version ver) + : proxy_(std::move(proxy)), buffer_size_(0), buffer_(), ver_(ver) + {} + + client::~client() {} + + bool client::set_connect_command(const epee::net_utils::ipv4_network_address& address) + { + switch (socks_version()) + { + case version::v4: + case version::v4a: + case version::v4a_tor: + break; + default: + return false; + } + + static_assert(sizeof(v4_header) < sizeof(buffer_), "buffer size too small for request"); + static_assert(0 < sizeof(buffer_), "buffer size too small for null termination"); + + // version 4 + const v4_header temp{4, v4_connect_command, address.port(), boost::endian::big_to_native(address.ip())}; + std::memcpy(std::addressof(buffer_), std::addressof(temp), sizeof(temp)); + buffer_[sizeof(temp)] = 0; + buffer_size_ = sizeof(temp) + 1; + + return true; + } + + bool client::set_connect_command(const boost::string_ref domain, std::uint16_t port) + { + switch (socks_version()) + { + case version::v4a: + case version::v4a_tor: + break; + + default: + return false; + } + + const std::size_t buf_used = write_domain_header(buffer_, v4_connect_command, port, domain); + buffer_size_ = buf_used; + return buf_used != 0; + } + + bool client::set_connect_command(const net::tor_address& address) + { + if (!address.is_unknown()) + return set_connect_command(address.host_str(), address.port()); + return false; + } + + bool client::set_resolve_command(boost::string_ref domain) + { + if (socks_version() != version::v4a_tor) + return false; + + const std::size_t buf_used = write_domain_header(buffer_, v4tor_resolve_command, 0, domain); + buffer_size_ = buf_used; + return buf_used != 0; + } + + bool client::connect_and_send(std::shared_ptr<client> self, const stream_type::endpoint& proxy_address) + { + if (self && !self->buffer().empty()) + { + client& alias = *self; + alias.proxy_.async_connect(proxy_address, write{std::move(self)}); + return true; + } + return false; + } + + bool client::send(std::shared_ptr<client> self) + { + if (self && !self->buffer().empty()) + { + client& alias = *self; + boost::asio::async_write(alias.proxy_, write::get_buffer(alias), read{std::move(self)}); + return true; + } + return false; + } +} // socks +} // net |