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Code Issues Releases Activity

[socks] try fix SOCKS5 upstream connection

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Signed-off-by: R4SAS <r4sas@i2pmail.org>
This commit is contained in:
R4SAS 2021-08-07 22:02:47 +03:00
parent 18cb3912e5
commit cb54a50dc5
1 changed files with 96 additions and 59 deletions
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155
libi2pd_client/SOCKS.cpp
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@ -30,6 +30,8 @@ namespace proxy
static const size_t SOCKS_FORWARDER_BUFFER_SIZE = 8192; static const size_t SOCKS_FORWARDER_BUFFER_SIZE = 8192;
static const size_t SOCKS_UPSTREAM_SOCKS4A_REPLY_SIZE = 8; static const size_t SOCKS_UPSTREAM_SOCKS4A_REPLY_SIZE = 8;
static const size_t SOCKS_UPSTREAM_SOCKS5_INIT_REPLY_SIZE = 2;
static const size_t SOCKS_UPSTREAM_SOCKS5_CONNECT_REPLY_MIN_SIZE = 10;
struct SOCKSDnsAddress struct SOCKSDnsAddress
{ {
@ -73,43 +75,43 @@ namespace proxy
}; };
enum authMethods enum authMethods
{ {
AUTH_NONE = 0, //No authentication, skip to next step AUTH_NONE = 0, // No authentication, skip to next step
AUTH_GSSAPI = 1, //GSSAPI authentication AUTH_GSSAPI = 1, // GSSAPI authentication
AUTH_USERPASSWD = 2, //Username and password AUTH_USERPASSWD = 2, // Username and password
AUTH_UNACCEPTABLE = 0xff //No acceptable method found AUTH_UNACCEPTABLE = 0xff // No acceptable method found
}; };
enum addrTypes enum addrTypes
{ {
ADDR_IPV4 = 1, //IPv4 address (4 octets) ADDR_IPV4 = 1, // IPv4 address (4 octets)
ADDR_DNS = 3, // DNS name (up to 255 octets) ADDR_DNS = 3, // DNS name (up to 255 octets)
ADDR_IPV6 = 4 //IPV6 address (16 octets) ADDR_IPV6 = 4 // IPV6 address (16 octets)
}; };
enum errTypes enum errTypes
{ {
SOCKS5_OK = 0, // No error for SOCKS5 SOCKS5_OK = 0, // No error for SOCKS5
SOCKS5_GEN_FAIL = 1, // General server failure SOCKS5_GEN_FAIL = 1, // General server failure
SOCKS5_RULE_DENIED = 2, // Connection disallowed by ruleset SOCKS5_RULE_DENIED = 2, // Connection disallowed by ruleset
SOCKS5_NET_UNREACH = 3, // Network unreachable SOCKS5_NET_UNREACH = 3, // Network unreachable
SOCKS5_HOST_UNREACH = 4, // Host unreachable SOCKS5_HOST_UNREACH = 4, // Host unreachable
SOCKS5_CONN_REFUSED = 5, // Connection refused by the peer SOCKS5_CONN_REFUSED = 5, // Connection refused by the peer
SOCKS5_TTL_EXPIRED = 6, // TTL Expired SOCKS5_TTL_EXPIRED = 6, // TTL Expired
SOCKS5_CMD_UNSUP = 7, // Command unsupported SOCKS5_CMD_UNSUP = 7, // Command unsupported
SOCKS5_ADDR_UNSUP = 8, // Address type unsupported SOCKS5_ADDR_UNSUP = 8, // Address type unsupported
SOCKS4_OK = 90, // No error for SOCKS4 SOCKS4_OK = 90, // No error for SOCKS4
SOCKS4_FAIL = 91, // Failed establishing connecting or not allowed SOCKS4_FAIL = 91, // Failed establishing connecting or not allowed
SOCKS4_IDENTD_MISSING = 92, // Couldn't connect to the identd server SOCKS4_IDENTD_MISSING = 92, // Couldn't connect to the identd server
SOCKS4_IDENTD_DIFFER = 93 // The ID reported by the application and by identd differ SOCKS4_IDENTD_DIFFER = 93 // The ID reported by the application and by identd differ
}; };
enum cmdTypes enum cmdTypes
{ {
CMD_CONNECT = 1, // TCP Connect CMD_CONNECT = 1, // TCP Connect
CMD_BIND = 2, // TCP Bind CMD_BIND = 2, // TCP Bind
CMD_UDP = 3 // UDP associate CMD_UDP = 3 // UDP associate
}; };
enum socksVersions enum socksVersions
{ {
SOCKS4 = 4, // SOCKS4 SOCKS4 = 4, // SOCKS4
SOCKS5 = 5 // SOCKS5 SOCKS5 = 5 // SOCKS5
}; };
union address union address
{ {
@ -127,7 +129,7 @@ namespace proxy
boost::asio::const_buffers_1 GenerateSOCKS5SelectAuth(authMethods method); 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 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); boost::asio::const_buffers_1 GenerateSOCKS5Response(errTypes error, addrTypes type, const address &addr, uint16_t port);
boost::asio::const_buffers_1 GenerateUpstreamRequest(); boost::asio::const_buffers_1 GenerateUpstreamRequest(int version, bool initial);
bool Socks5ChooseAuth(); bool Socks5ChooseAuth();
void SocksRequestFailed(errTypes error); void SocksRequestFailed(errTypes error);
void SocksRequestSuccess(); void SocksRequestSuccess();
@ -139,7 +141,7 @@ namespace proxy
void SocksUpstreamSuccess(); void SocksUpstreamSuccess();
void AsyncUpstreamSockRead(); void AsyncUpstreamSockRead();
void SendUpstreamRequest(); void SendUpstreamRequest(int version, bool initial);
void HandleUpstreamData(uint8_t * buff, std::size_t len); void HandleUpstreamData(uint8_t * buff, std::size_t len);
void HandleUpstreamSockSend(const boost::system::error_code & ecode, std::size_t bytes_transfered); void HandleUpstreamSockSend(const boost::system::error_code & ecode, std::size_t bytes_transfered);
void HandleUpstreamSockRecv(const boost::system::error_code & ecode, std::size_t bytes_transfered); void HandleUpstreamSockRecv(const boost::system::error_code & ecode, std::size_t bytes_transfered);
@ -154,9 +156,9 @@ namespace proxy
std::shared_ptr<i2p::stream::Stream> m_stream; std::shared_ptr<i2p::stream::Stream> m_stream;
uint8_t *m_remaining_data; //Data left to be sent uint8_t *m_remaining_data; //Data left to be sent
uint8_t *m_remaining_upstream_data; //upstream data left to be forwarded uint8_t *m_remaining_upstream_data; //upstream data left to be forwarded
uint8_t m_response[7+max_socks_hostname_size]; uint8_t m_response[7 + max_socks_hostname_size];
uint8_t m_upstream_response[SOCKS_UPSTREAM_SOCKS4A_REPLY_SIZE]; uint8_t m_upstream_response[SOCKS_UPSTREAM_SOCKS4A_REPLY_SIZE];
uint8_t m_upstream_request[14+max_socks_hostname_size]; uint8_t m_upstream_request[14 + max_socks_hostname_size];
std::size_t m_upstream_response_len; std::size_t m_upstream_response_len;
address m_address; //Address address m_address; //Address
std::size_t m_remaining_data_len; //Size of the data left to be sent std::size_t m_remaining_data_len; //Size of the data left to be sent
@ -274,33 +276,49 @@ namespace proxy
return boost::asio::const_buffers_1(m_response, size); return boost::asio::const_buffers_1(m_response, size);
} }
boost::asio::const_buffers_1 SOCKSHandler::GenerateUpstreamRequest() boost::asio::const_buffers_1 SOCKSHandler::GenerateUpstreamRequest(int version, bool initial)
{ {
size_t upstreamRequestSize = 0; size_t upstreamRequestSize = 0;
// TODO: negotiate with upstream // TODO: negotiate with upstream
// SOCKS 4a if (version == 5) // SOCKS5
m_upstream_request[0] = '\x04'; //version {
m_upstream_request[1] = m_cmd; if (initial)
htobe16buf(m_upstream_request + 2, m_port); {
m_upstream_request[4] = 0; m_upstream_request[0] = '\x05'; // VER
m_upstream_request[5] = 0; m_upstream_request[1] = 1; // NAUTH
m_upstream_request[6] = 0; m_upstream_request[2] = 0; // AUTH
m_upstream_request[7] = 1; upstreamRequestSize += 3;
// user id }
m_upstream_request[8] = 'i'; else
m_upstream_request[9] = '2'; {
m_upstream_request[10] = 'p'; return GenerateSOCKS5Response(SOCKS5_GEN_FAIL, m_addrtype, m_address, m_port); // dirty hack, SOCKS5_GEN_FAIL == 1, that's a "establish a TCP/IP stream connection" command
m_upstream_request[11] = 'd'; }
m_upstream_request[12] = 0; }
upstreamRequestSize += 13; else if (version == 4) // SOCKS4a
if (m_address.dns.size <= max_socks_hostname_size - ( upstreamRequestSize + 1) ) { {
// bounds check okay m_upstream_request[0] = '\x04'; // VER
memcpy(m_upstream_request + upstreamRequestSize, m_address.dns.value, m_address.dns.size); m_upstream_request[1] = m_cmd;
upstreamRequestSize += m_address.dns.size; htobe16buf(m_upstream_request + 2, m_port);
// null terminate m_upstream_request[4] = 0;
m_upstream_request[++upstreamRequestSize] = 0; m_upstream_request[5] = 0;
} else { m_upstream_request[6] = 0;
LogPrint(eLogError, "SOCKS: BUG!!! m_addr.dns.sizs > max_socks_hostname - ( upstreamRequestSize + 1 ) )"); m_upstream_request[7] = 1;
// user id
m_upstream_request[8] = 'i';
m_upstream_request[9] = '2';
m_upstream_request[10] = 'p';
m_upstream_request[11] = 'd';
m_upstream_request[12] = 0;
upstreamRequestSize += 13;
if (m_address.dns.size <= max_socks_hostname_size - ( upstreamRequestSize + 1) ) {
// bounds check okay
memcpy(m_upstream_request + upstreamRequestSize, m_address.dns.value, m_address.dns.size);
upstreamRequestSize += m_address.dns.size;
// null terminate
m_upstream_request[++upstreamRequestSize] = 0;
} else {
LogPrint(eLogError, "SOCKS: BUG!!! m_addr.dns.size > max_socks_hostname - ( upstreamRequestSize + 1 ) )");
}
} }
return boost::asio::const_buffers_1(m_upstream_request, upstreamRequestSize); return boost::asio::const_buffers_1(m_upstream_request, upstreamRequestSize);
} }
@ -417,6 +435,7 @@ namespace proxy
{ {
case GET_SOCKSV: case GET_SOCKSV:
m_socksv = (SOCKSHandler::socksVersions) *sock_buff; m_socksv = (SOCKSHandler::socksVersions) *sock_buff;
LogPrint(eLogInfo, "SOCKS: received version: ", ((int)*sock_buff));
switch (*sock_buff) switch (*sock_buff)
{ {
case SOCKS4: case SOCKS4:
@ -704,7 +723,7 @@ namespace proxy
break; break;
case SOCKS5: case SOCKS5:
LogPrint(eLogInfo, "SOCKS: v5 connection success"); LogPrint(eLogInfo, "SOCKS: v5 connection success");
//HACK only 16 bits passed in port as SOCKS5 doesn't allow for more // HACK only 16 bits passed in port as SOCKS5 doesn't allow for more
response = GenerateSOCKS5Response(SOCKS5_OK, ADDR_DNS, m_address, m_port); response = GenerateSOCKS5Response(SOCKS5_OK, ADDR_DNS, m_address, m_port);
break; break;
} }
@ -715,7 +734,6 @@ namespace proxy
GetOwner()->AddHandler(forwarder); GetOwner()->AddHandler(forwarder);
forwarder->Start(); forwarder->Start();
Terminate(); Terminate();
} }
void SOCKSHandler::HandleUpstreamData(uint8_t * dataptr, std::size_t len) void SOCKSHandler::HandleUpstreamData(uint8_t * dataptr, std::size_t len)
@ -723,14 +741,33 @@ namespace proxy
if (m_state == UPSTREAM_HANDSHAKE) { if (m_state == UPSTREAM_HANDSHAKE) {
m_upstream_response_len += len; m_upstream_response_len += len;
// handle handshake data // handle handshake data
if (m_upstream_response_len < SOCKS_UPSTREAM_SOCKS4A_REPLY_SIZE) { if (m_upstream_response_len == SOCKS_UPSTREAM_SOCKS5_INIT_REPLY_SIZE) {
if (m_upstream_response[0] == '\x05' && m_upstream_response[1] != AUTH_UNACCEPTABLE) {
LogPrint(eLogInfo, "SOCKS: upstream proxy: success greeting");
SendUpstreamRequest(m_socksv, false);
} else {
LogPrint(eLogError, "SOCKS: upstream proxy failure: no acceptable methods were offered");
SocksRequestFailed(SOCKS5_GEN_FAIL);
}
}
else if (m_upstream_response[0] == '\x05' && m_upstream_response_len >= SOCKS_UPSTREAM_SOCKS5_CONNECT_REPLY_MIN_SIZE)
{
uint8_t resp = m_upstream_response[1];
if (resp == SOCKS5_OK) {
SocksUpstreamSuccess();
} else {
LogPrint(eLogError, "SOCKS: upstream proxy failure: ", (int) resp);
SocksRequestFailed(SOCKS5_GEN_FAIL);
}
}
else if (m_upstream_response_len < SOCKS_UPSTREAM_SOCKS4A_REPLY_SIZE) {
// too small, continue reading // too small, continue reading
AsyncUpstreamSockRead(); AsyncUpstreamSockRead();
} else if (len == SOCKS_UPSTREAM_SOCKS4A_REPLY_SIZE) { } else if (len == SOCKS_UPSTREAM_SOCKS4A_REPLY_SIZE) {
// just right // just right
uint8_t resp = m_upstream_response[1]; uint8_t resp = m_upstream_response[1];
if (resp == SOCKS4_OK) { if (resp == SOCKS4_OK) {
// we have connected ! // we have connected!
SocksUpstreamSuccess(); SocksUpstreamSuccess();
} else { } else {
// upstream failure // upstream failure
@ -748,12 +785,12 @@ namespace proxy
} }
} }
void SOCKSHandler::SendUpstreamRequest() void SOCKSHandler::SendUpstreamRequest(int version, bool initial)
{ {
LogPrint(eLogInfo, "SOCKS: Negotiating with upstream proxy"); LogPrint(eLogInfo, "SOCKS: Negotiating with upstream proxy");
EnterState(UPSTREAM_HANDSHAKE); EnterState(UPSTREAM_HANDSHAKE);
if (m_upstreamSock) { if (m_upstreamSock) {
boost::asio::write(*m_upstreamSock, GenerateUpstreamRequest()); boost::asio::write(*m_upstreamSock, GenerateUpstreamRequest(version, initial));
AsyncUpstreamSockRead(); AsyncUpstreamSockRead();
} else { } else {
LogPrint(eLogError, "SOCKS: No upstream socket to send handshake to"); LogPrint(eLogError, "SOCKS: No upstream socket to send handshake to");
@ -768,7 +805,7 @@ namespace proxy
return; return;
} }
LogPrint(eLogInfo, "SOCKS: Connected to upstream proxy"); LogPrint(eLogInfo, "SOCKS: Connected to upstream proxy");
SendUpstreamRequest(); SendUpstreamRequest(m_socksv, true); // try SOCKS5 first
} }
void SOCKSHandler::HandleUpstreamResolved(const boost::system::error_code & ecode, boost::asio::ip::tcp::resolver::iterator itr) void SOCKSHandler::HandleUpstreamResolved(const boost::system::error_code & ecode, boost::asio::ip::tcp::resolver::iterator itr)