From f383ebb718ab635aac93681c87b814c2026eb88f Mon Sep 17 00:00:00 2001 From: "Francisco Blas (klondike) Izquierdo Riera" Date: Mon, 5 Jan 2015 12:37:52 +0100 Subject: [PATCH] Return adequate SOCKS replies --- SOCKS.cpp | 171 +++++++++++++++++++++++++++++++----------------------- SOCKS.h | 44 +++++++++----- 2 files changed, 129 insertions(+), 86 deletions(-) diff --git a/SOCKS.cpp b/SOCKS.cpp index a92ead5f..7b186e36 100644 --- a/SOCKS.cpp +++ b/SOCKS.cpp @@ -4,6 +4,7 @@ #include "Destination.h" #include "ClientContext.h" #include "I2PEndian.h" +#include #include namespace i2p @@ -28,73 +29,104 @@ namespace proxy delete this; // HACK: ew } + boost::asio::const_buffers_1 SOCKSHandler::GenerateSOCKS5SelectAuth(SOCKSHandler::authMethods method) + { + response[0] = '\x05'; //Version + response[1] = method; //Response code + return boost::asio::const_buffers_1(response,2); + } + + boost::asio::const_buffers_1 SOCKSHandler::GenerateSOCKS4Response(SOCKSHandler::errTypes error, uint32_t ip, uint16_t port) + { + assert(error >= SOCKS4_OK); + assert(type == ADDR_IPV4); + response[0] = '\x00'; //Version + response[1] = error; //Response code + htobe16buf(response+2,port); //Port + htobe32buf(response+4,ip); //IP + return boost::asio::const_buffers_1(response,8); + } + + boost::asio::const_buffers_1 SOCKSHandler::GenerateSOCKS5Response(SOCKSHandler::errTypes error, SOCKSHandler::addrTypes type, + const SOCKSHandler::address &addr, uint16_t port) + { + size_t size; + assert(error <= SOCKS5_ADDR_UNSUP); + response[0] = '\x05'; //Version + response[1] = error; //Response code + response[2] = '\x00'; //RSV + response[3] = type; //Address type + switch (type) { + case ADDR_IPV4: + size = 10; + htobe32buf(response+4,addr.ip); + break; + case ADDR_IPV6: + size = 22; + memcpy(response+4,addr.ipv6, 16); + break; + case ADDR_DNS: + size = 7+addr.dns.size; + response[4] = addr.dns.size; + memcpy(response+5,addr.dns.value, addr.dns.size); + break; + } + htobe16buf(response+size-2,port); //Port + return boost::asio::const_buffers_1(response,size); + } + + /* Ah ah ah, you didn't say the magic word */ void SOCKSHandler::Socks5AuthNegoFailed() { LogPrint(eLogWarning,"--- SOCKS5 authentication negotiation failed"); - boost::asio::async_write(*m_sock, boost::asio::buffer("\x05\xff",2), - std::bind(&SOCKSHandler::SentSocksFailed, this, - std::placeholders::_1)); + boost::asio::async_write(*m_sock, GenerateSOCKS5SelectAuth(AUTH_UNACCEPTABLE), + std::bind(&SOCKSHandler::SentSocksFailed, this, std::placeholders::_1)); } void SOCKSHandler::Socks5ChooseAuth() { - LogPrint(eLogDebug,"--- SOCKS5 choosing authentication method"); - //TODO: Choose right method - boost::asio::async_write(*m_sock, boost::asio::buffer("\x05\x00",2), - std::bind(&SOCKSHandler::SentSocksResponse, this, - std::placeholders::_1, nullptr)); + LogPrint(eLogDebug,"--- SOCKS5 choosing authentication method: ", m_authchosen); + boost::asio::async_write(*m_sock, GenerateSOCKS5SelectAuth(m_authchosen), + std::bind(&SOCKSHandler::SentSocksResponse, this, std::placeholders::_1)); } - static const char *socks5Replies[9] = { - "\x05\x00\x00\x01\x00\x00\x00\x00\x00\x00", - "\x05\x01\x00\x01\x00\x00\x00\x00\x00\x00", - "\x05\x02\x00\x01\x00\x00\x00\x00\x00\x00", - "\x05\x03\x00\x01\x00\x00\x00\x00\x00\x00", - "\x05\x04\x00\x01\x00\x00\x00\x00\x00\x00", - "\x05\x05\x00\x01\x00\x00\x00\x00\x00\x00", - "\x05\x06\x00\x01\x00\x00\x00\x00\x00\x00", - "\x05\x07\x00\x01\x00\x00\x00\x00\x00\x00", - "\x05\x08\x00\x01\x00\x00\x00\x00\x00\x00" }; - - /* All hope is lost */ - void SOCKSHandler::SocksRequestFailed() + /* All hope is lost beyond this point */ + void SOCKSHandler::SocksRequestFailed(SOCKSHandler::errTypes error) { + boost::asio::const_buffers_1 response(nullptr,0); + assert(error != SOCKS4_OK && error != SOCKS5_OK); switch (m_socksv) { case SOCKS4: - LogPrint(eLogWarning,"--- SOCKS4 failed"); - //TODO: send the right response - boost::asio::async_write(*m_sock, boost::asio::buffer("\x00\x5b\x00\x00\x00\x00\x00\x00",8), - std::bind(&SOCKSHandler::SentSocksFailed, this, std::placeholders::_1)); + LogPrint(eLogWarning,"--- SOCKS4 failed: ", error); + if (error < SOCKS4_OK) error = SOCKS4_FAIL; //Transparently map SOCKS5 errors + response = GenerateSOCKS4Response(error, m_4aip, m_port); break; case SOCKS5: - assert(m_error <= SOCKS5_ADDR_UNSUP); - LogPrint(eLogWarning,"--- SOCKS5 failed"); - //TODO: use error properly and address type m_error - boost::asio::async_write(*m_sock, boost::asio::buffer(socks5Replies[m_error],10), - std::bind(&SOCKSHandler::SentSocksFailed, this, std::placeholders::_1)); + LogPrint(eLogWarning,"--- SOCKS5 failed: ", error); + response = GenerateSOCKS5Response(error, m_addrtype, m_address, m_port); break; } + boost::asio::async_write(*m_sock, response, std::bind(&SOCKSHandler::SentSocksFailed, this, std::placeholders::_1)); } void SOCKSHandler::SocksRequestSuccess() { - std::shared_ptr> response(new std::vector); + boost::asio::const_buffers_1 response(nullptr,0); + //TODO: this should depend on things like the command type and callbacks may change switch (m_socksv) { case SOCKS4: LogPrint(eLogInfo,"--- SOCKS4 connection success"); - //TODO: send the right response - boost::asio::async_write(*m_sock, boost::asio::buffer("\x00\x5a\x00\x00\x00\x00\x00\x00",8), - std::bind(&SOCKSHandler::SentSocksResponse, this, - std::placeholders::_1, nullptr)); + response = GenerateSOCKS4Response(SOCKS4_OK, m_4aip, m_port); break; case SOCKS5: LogPrint(eLogInfo,"--- SOCKS5 connection success"); - //TODO: send the right response using the port? and the localside i2p address - boost::asio::async_write(*m_sock, boost::asio::buffer("\x05\x00\x00\x01\x00\x00\x00\x00\x00\x00",10), - std::bind(&SOCKSHandler::SentSocksResponse, this, - std::placeholders::_1, response)); + auto s = i2p::client::context.GetAddressBook().ToAddress(m_parent->GetLocalDestination()->GetIdentHash()); + address ad; ad.dns.FromString(s); + //HACK only 16 bits passed in port as SOCKS5 doesn't allow for more + response = GenerateSOCKS5Response(SOCKS5_OK, ADDR_DNS, ad, m_stream->GetSendStreamID()); break; } + boost::asio::async_write(*m_sock, response, std::bind(&SOCKSHandler::SentSocksResponse, this, std::placeholders::_1)); } @@ -197,8 +229,7 @@ namespace proxy if ( m_cmd != CMD_CONNECT ) { //TODO: we need to support binds and other shit! LogPrint(eLogError,"--- SOCKS unsupported command: ", m_cmd); - m_error = SOCKS5_CMD_UNSUP; - SocksRequestFailed(); + SocksRequestFailed(SOCKS5_CMD_UNSUP); return false; } //TODO: we may want to support other address types! @@ -206,24 +237,23 @@ namespace proxy switch (m_socksv) { case SOCKS5: LogPrint(eLogError,"--- SOCKS5 unsupported address type: ", m_addrtype); - m_error = SOCKS5_ADDR_UNSUP; break; case SOCKS4: LogPrint(eLogError,"--- SOCKS4a rejected because it's actually SOCKS4"); break; } - SocksRequestFailed(); + SocksRequestFailed(SOCKS5_ADDR_UNSUP); return false; } //TODO: we may want to support other domains - if(m_addrtype == ADDR_DNS && m_destination.find(".i2p") == std::string::npos) { - LogPrint(eLogError,"--- SOCKS invalid hostname: ", m_destination); - m_error = SOCKS5_ADDR_UNSUP; - SocksRequestFailed(); + if(m_addrtype == ADDR_DNS && m_address.dns.ToString().find(".i2p") == std::string::npos) { + LogPrint(eLogError,"--- SOCKS invalid hostname: ", m_address.dns.ToString()); + SocksRequestFailed(SOCKS5_ADDR_UNSUP); return false; } return true; } + std::size_t SOCKSHandler::HandleSOCKSRequest(uint8_t *sock_buff, std::size_t len) { std::size_t rv = 0; @@ -240,8 +270,7 @@ namespace proxy if (m_socksv == SOCKS5) break; default: LogPrint(eLogError,"--- SOCKS invalid command: ", ((int)*sock_buff)); - m_error = SOCKS5_GEN_FAIL; - SocksRequestFailed(); + SocksRequestFailed(SOCKS5_GEN_FAIL); return 0; } m_cmd = (SOCKSHandler::cmdTypes)*sock_buff; @@ -256,28 +285,29 @@ namespace proxy if (m_addrleft == 0) { switch (m_socksv) { case SOCKS5: m_pstate = DONE; break; - case SOCKS4: m_pstate = GET_IPV4; m_addrleft = 4; break; + case SOCKS4: m_pstate = GET_IPV4; m_address.ip = 0; m_addrleft = 4; break; } } break; case GET_IPV4: - m_ip = (m_ip << 8)|((uint32_t)*sock_buff); + m_address.ip = (m_address.ip << 8)|((uint32_t)*sock_buff); m_addrleft--; if (m_addrleft == 0) { switch (m_socksv) { case SOCKS5: m_pstate = GET_PORT; m_addrleft = 2; break; - case SOCKS4: m_pstate = GET4_IDENT; break; + case SOCKS4: m_pstate = GET4_IDENT; m_4aip = m_address.ip; break; } } break; case GET4_IDENT: if (!*sock_buff) { - if( m_ip == 0 || m_ip > 255 ) { + if( m_4aip == 0 || m_4aip > 255 ) { m_addrtype = ADDR_IPV4; m_pstate = DONE; } else { m_addrtype = ADDR_DNS; m_pstate = GET4A_HOST; + m_address.dns.size = 0; } } break; @@ -286,18 +316,17 @@ namespace proxy m_pstate = DONE; break; } - if (m_destination.size() > max_socks_hostname_size) { + if (m_address.dns.size >= max_socks_hostname_size) { LogPrint(eLogError,"--- SOCKS4a destination is too large"); - SocksRequestFailed(); + SocksRequestFailed(SOCKS4_FAIL); return 0; } - m_destination.push_back(*sock_buff); + m_address.dns.push_back(*sock_buff); break; case GET5_REQUESTV: if (*sock_buff != SOCKS5) { LogPrint(eLogError,"--- SOCKS5 rejected unknown request version: ", ((int)*sock_buff)); - m_error = SOCKS5_GEN_FAIL; - SocksRequestFailed(); + SocksRequestFailed(SOCKS5_GEN_FAIL); return 0; } m_pstate = GET_COMMAND; @@ -305,27 +334,25 @@ namespace proxy case GET5_GETRSV: if ( *sock_buff != 0 ) { LogPrint(eLogError,"--- SOCKS5 unknown reserved field: ", ((int)*sock_buff)); - m_error = SOCKS5_GEN_FAIL; - SocksRequestFailed(); + SocksRequestFailed(SOCKS5_GEN_FAIL); return 0; } m_pstate = GET5_GETADDRTYPE; break; case GET5_GETADDRTYPE: switch (*sock_buff) { - case ADDR_IPV4: m_pstate = GET_IPV4; m_addrleft = 4; break; + case ADDR_IPV4: m_pstate = GET_IPV4; m_address.ip = 0; m_addrleft = 4; break; case ADDR_IPV6: m_pstate = GET5_IPV6; m_addrleft = 16; break; case ADDR_DNS : m_pstate = GET5_HOST_SIZE; break; default: LogPrint(eLogError,"--- SOCKS5 unknown address type: ", ((int)*sock_buff)); - m_error = SOCKS5_GEN_FAIL; - SocksRequestFailed(); + SocksRequestFailed(SOCKS5_GEN_FAIL); return 0; } m_addrtype = (SOCKSHandler::addrTypes)*sock_buff; break; case GET5_IPV6: - m_ipv6[16-m_addrleft] = *sock_buff; + m_address.ipv6[16-m_addrleft] = *sock_buff; m_addrleft--; if (m_addrleft == 0) { m_pstate = GET_PORT; @@ -334,10 +361,11 @@ namespace proxy break; case GET5_HOST_SIZE: m_addrleft = *sock_buff; + m_address.dns.size = 0; m_pstate = GET5_HOST; break; case GET5_HOST: - m_destination.push_back(*sock_buff); + m_address.dns.push_back(*sock_buff); m_addrleft--; if (m_addrleft == 0) { m_pstate = GET_PORT; @@ -381,16 +409,16 @@ namespace proxy assert(!(m_state == READY && m_need_more)); if (m_state == READY) { - LogPrint(eLogInfo,"--- SOCKS requested ", m_destination, ":" , m_port); + LogPrint(eLogInfo,"--- SOCKS requested ", m_address.dns.ToString(), ":" , m_port); if (pos != len) { LogPrint(eLogError,"--- SOCKS rejected because we can't handle extra data"); - SocksRequestFailed(); + SocksRequestFailed(SOCKS5_GEN_FAIL); return ; } m_parent->GetLocalDestination ()->CreateStream ( std::bind (&SOCKSHandler::HandleStreamRequestComplete, - this, std::placeholders::_1), m_destination, m_port); + this, std::placeholders::_1), m_address.dns.ToString(), m_port); } else if (m_need_more) { LogPrint (eLogDebug,"--- SOCKS Need more data"); AsyncSockRead(); @@ -407,9 +435,8 @@ namespace proxy } } - void SOCKSHandler::SentSocksResponse(const boost::system::error_code & ecode, std::shared_ptr> response) + void SOCKSHandler::SentSocksResponse(const boost::system::error_code & ecode) { - response.reset(); // Information wants to be free, so does memory if (!ecode) { if(m_state == READY) { LogPrint (eLogInfo,"--- SOCKS New I2PTunnel connection"); @@ -431,12 +458,12 @@ namespace proxy void SOCKSHandler::HandleStreamRequestComplete (std::shared_ptr stream) { if (stream) { + //TODO: test the stream is open if it isn't fail with connrefused m_stream = stream; SocksRequestSuccess(); } else { - m_error = SOCKS5_HOST_UNREACH; LogPrint (eLogError,"--- SOCKS Issue when creating the stream, check the previous warnings for more info."); - SocksRequestFailed(); + SocksRequestFailed(SOCKS5_HOST_UNREACH); } } diff --git a/SOCKS.h b/SOCKS.h index 873fa2c6..6fab0fbf 100644 --- a/SOCKS.h +++ b/SOCKS.h @@ -2,7 +2,7 @@ #define SOCKS_H__ #include -#include +#include #include #include "Identity.h" #include "Streaming.h" @@ -16,9 +16,20 @@ namespace proxy const size_t socks_buffer_size = 8192; const size_t max_socks_hostname_size = 255; // Limit for socks5 and bad idea to traverse + struct SOCKSDnsAddress { + uint8_t size; + char value[max_socks_hostname_size]; + void FromString (std::string str) { + size = str.length(); + if (str.length() > max_socks_hostname_size) size = max_socks_hostname_size; + memcpy(value,str.c_str(),size); + } + std::string ToString() { return std::string(value, size); } + void push_back (char c) { value[size++] = c; } + }; + class SOCKSServer; class SOCKSHandler { - private: enum state { GET_VERSION, // Get SOCKS version @@ -78,9 +89,12 @@ namespace proxy SOCKS4 = 4, // SOCKS4 SOCKS5 = 5 // SOCKS5 }; + union address { + uint32_t ip; + SOCKSDnsAddress dns; + uint8_t ipv6[16]; + }; - - void GotClientRequest(boost::system::error_code & ecode, std::string & host, uint16_t port); std::size_t HandleData(uint8_t *sock_buff, std::size_t len); std::size_t HandleVersion(uint8_t *sock_buff); std::size_t HandleSOCKS5AuthNego(uint8_t *sock_buff, std::size_t len); @@ -91,13 +105,16 @@ namespace proxy void CloseSock(); void CloseStream(); void AsyncSockRead(); + boost::asio::const_buffers_1 GenerateSOCKS5SelectAuth(authMethods method); + boost::asio::const_buffers_1 GenerateSOCKS4Response(errTypes error, uint32_t ip, uint16_t port); + boost::asio::const_buffers_1 GenerateSOCKS5Response(errTypes error, addrTypes type, const address &addr, uint16_t port); void Socks5AuthNegoFailed(); void Socks5ChooseAuth(); - void SocksRequestFailed(); + void SocksRequestFailed(errTypes error); void SocksRequestSuccess(); - void SentSocksFailed(const boost::system::error_code & ecode); //HACK: we need to pass the shared_ptr to ensure the buffer will live enough - void SentSocksResponse(const boost::system::error_code & ecode, std::shared_ptr> response); + void SentSocksFailed(const boost::system::error_code & ecode); + void SentSocksResponse(const boost::system::error_code & ecode); void HandleStreamRequestComplete (std::shared_ptr stream); uint8_t m_sock_buff[socks_buffer_size]; @@ -108,24 +125,23 @@ namespace proxy parseState m_pstate; uint8_t m_command; uint16_t m_port; - uint32_t m_ip; - uint8_t m_ipv6[16]; - std::string m_destination; + uint32_t m_4aip; //Used in 4a requests uint8_t m_authleft; //Authentication methods left //TODO: this will probably be more elegant as enums authMethods m_authchosen; //Authentication chosen addrTypes m_addrtype; //Address type chosen - uint8_t m_addrleft; //Octets of DNS address left - errTypes m_error; //Error cause + address m_address; //Address + uint8_t m_addrleft; //Octets of current address left socksVersions m_socksv; //Socks version cmdTypes m_cmd; // Command requested bool m_need_more; //The parser still needs to receive more data + uint8_t response[7+max_socks_hostname_size]; public: SOCKSHandler(SOCKSServer * parent, boost::asio::ip::tcp::socket * sock) : m_parent(parent), m_sock(sock), m_stream(nullptr), m_state(GET_VERSION), - m_authchosen(AUTH_UNACCEPTABLE), m_addrtype(ADDR_IPV4), m_error(SOCKS5_GEN_FAIL) - { AsyncSockRead(); m_destination.reserve(max_socks_hostname_size+1); } + m_authchosen(AUTH_UNACCEPTABLE), m_addrtype(ADDR_IPV4) + { m_address.ip = 0; AsyncSockRead(); } ~SOCKSHandler() { CloseSock(); CloseStream(); } };