diff --git a/analyzer/tcp/socks5.go b/analyzer/tcp/socks5.go new file mode 100644 index 0000000..6977e94 --- /dev/null +++ b/analyzer/tcp/socks5.go @@ -0,0 +1,361 @@ +package tcp + +import ( + "github.com/apernet/OpenGFW/analyzer" + "github.com/apernet/OpenGFW/analyzer/utils" + "net" +) + +const ( + Socks5Version = 0x05 + + CmdTCPConnect = 0x01 + CmdTCPBind = 0x02 + CmdUDPAssociate = 0x03 + + AuthNotRequired = 0x00 + AuthPassword = 0x02 + AuthNoMatchingMethod = 0xFF + + AuthSuccess = 0x00 + AuthFailure = 0x01 + + AddrTypeIPv4 = 0x01 + AddrTypeDomain = 0x03 + AddrTypeIPv6 = 0x04 +) + +var _ analyzer.Analyzer = (*Socks5Analyzer)(nil) + +type Socks5Analyzer struct{} + +func (a *Socks5Analyzer) Name() string { + return "socks5" +} + +func (a *Socks5Analyzer) Limit() int { + // TODO: more precise calculate + return 0 +} + +func (a *Socks5Analyzer) NewTCP(info analyzer.TCPInfo, logger analyzer.Logger) analyzer.TCPStream { + return newSocksStream(logger) +} + +type socks5Stream struct { + logger analyzer.Logger + + reqBuf *utils.ByteBuffer + reqMap analyzer.PropMap + reqUpdated bool + reqLSM *utils.LinearStateMachine + reqDone bool + + respBuf *utils.ByteBuffer + respMap analyzer.PropMap + respUpdated bool + respLSM *utils.LinearStateMachine + respDone bool + + authReqMethod int + authUsername string + authPassword string + + authRespMethod int +} + +func newSocksStream(logger analyzer.Logger) *socks5Stream { + s := &socks5Stream{logger: logger, reqBuf: &utils.ByteBuffer{}, respBuf: &utils.ByteBuffer{}} + s.reqLSM = utils.NewLinearStateMachine( + s.parseSocks5ReqVersion, + s.parseSocks5ReqMethod, + s.parseSocks5ReqAuth, + s.parseSocks5ReqConnInfo, + ) + s.respLSM = utils.NewLinearStateMachine( + s.parseSocks5RespVerAndMethod, + s.parseSocks5RespAuth, + s.parseSocks5RespConnInfo, + ) + return s +} + +func (s *socks5Stream) Feed(rev, start, end bool, skip int, data []byte) (u *analyzer.PropUpdate, d bool) { + if skip != 0 { + return nil, true + } + if len(data) == 0 { + return nil, false + } + var update *analyzer.PropUpdate + var cancelled bool + if rev { + s.respBuf.Append(data) + s.respUpdated = false + cancelled, s.respDone = s.respLSM.Run() + if s.respUpdated { + update = &analyzer.PropUpdate{ + Type: analyzer.PropUpdateMerge, + M: analyzer.PropMap{"resp": s.respMap}, + } + s.respUpdated = false + } + } else { + s.reqBuf.Append(data) + s.reqUpdated = false + cancelled, s.reqDone = s.reqLSM.Run() + if s.reqUpdated { + update = &analyzer.PropUpdate{ + Type: analyzer.PropUpdateMerge, + M: analyzer.PropMap{"req": s.reqMap}, + } + s.reqUpdated = false + } + } + return update, cancelled || (s.reqDone && s.respDone) +} + +func (s *socks5Stream) Close(limited bool) *analyzer.PropUpdate { + s.reqBuf.Reset() + s.respBuf.Reset() + s.reqMap = nil + s.respMap = nil + return nil +} + +func (s *socks5Stream) parseSocks5ReqVersion() utils.LSMAction { + socksVer, ok := s.reqBuf.GetByte(true) + if !ok { + return utils.LSMActionPause + } + if socksVer != Socks5Version { + return utils.LSMActionCancel + } + return utils.LSMActionNext +} + +func (s *socks5Stream) parseSocks5ReqMethod() utils.LSMAction { + nMethods, ok := s.reqBuf.GetByte(false) + if !ok { + return utils.LSMActionPause + } + methods, ok := s.reqBuf.Get(int(nMethods)+1, true) + if !ok { + return utils.LSMActionPause + } + + // For convenience, we only take the first method we can process + s.authReqMethod = AuthNoMatchingMethod + for _, method := range methods[1:] { + switch method { + case AuthNotRequired: + s.authReqMethod = AuthNotRequired + break + case AuthPassword: + s.authReqMethod = AuthPassword + break + default: + // TODO: more auth method to support + } + } + s.reqMap = make(analyzer.PropMap) + return utils.LSMActionNext +} + +func (s *socks5Stream) parseSocks5ReqAuth() utils.LSMAction { + switch s.authReqMethod { + case AuthNotRequired: + s.reqMap["auth"] = analyzer.PropMap{"method": s.authReqMethod} + case AuthPassword: + meta, ok := s.reqBuf.Get(2, false) + if !ok { + return utils.LSMActionPause + } + if meta[0] != 0x01 { + return utils.LSMActionCancel + } + usernameLen := int(meta[1]) + meta, ok = s.reqBuf.Get(usernameLen+3, false) + if !ok { + return utils.LSMActionPause + } + passwordLen := int(meta[usernameLen+2]) + meta, ok = s.reqBuf.Get(usernameLen+passwordLen+3, true) + if !ok { + return utils.LSMActionPause + } + s.authUsername = string(meta[2 : usernameLen+2]) + s.authPassword = string(meta[usernameLen+3:]) + s.reqMap["auth"] = analyzer.PropMap{ + "method": s.authReqMethod, + "username": s.authUsername, + "password": s.authPassword, + } + default: + return utils.LSMActionCancel + } + s.reqUpdated = true + return utils.LSMActionNext +} + +func (s *socks5Stream) parseSocks5ReqConnInfo() utils.LSMAction { + /* preInfo struct + +----+-----+-------+------+-------------+ + |VER | CMD | RSV | ATYP | DST.ADDR(1) | + +----+-----+-------+------+-------------+ + */ + preInfo, ok := s.reqBuf.Get(5, false) + if !ok { + return utils.LSMActionPause + } + + // verify socks version + if preInfo[0] != 0x05 { + return utils.LSMActionCancel + } + + var pktLen int + switch int(preInfo[3]) { + case AddrTypeIPv4: + pktLen = 10 + case AddrTypeDomain: + domainLen := int(preInfo[4]) + pktLen = 7 + domainLen + case AddrTypeIPv6: + pktLen = 22 + default: + return utils.LSMActionCancel + } + + pkt, ok := s.reqBuf.Get(pktLen, true) + if !ok { + return utils.LSMActionPause + } + + // parse cmd + cmd := int(pkt[1]) + if cmd != CmdTCPConnect && cmd != CmdTCPBind && cmd != CmdUDPAssociate { + return utils.LSMActionCancel + } + s.reqMap["cmd"] = cmd + + // parse addr type + addrType := int(pkt[3]) + var addr string + switch addrType { + case AddrTypeIPv4: + addr = net.IPv4(pkt[4], pkt[5], pkt[6], pkt[7]).String() + case AddrTypeDomain: + addr = string(pkt[5 : 5+pkt[4]]) + case AddrTypeIPv6: + addr = net.IP(pkt[4 : 4+net.IPv6len]).String() + default: + return utils.LSMActionCancel + } + s.reqMap["addr_type"] = addrType + s.reqMap["addr"] = addr + + // parse port + port := int(pkt[pktLen-2])<<8 | int(pkt[pktLen-1]) + s.reqMap["port"] = port + s.reqUpdated = true + return utils.LSMActionNext +} + +func (s *socks5Stream) parseSocks5RespVerAndMethod() utils.LSMAction { + verAndMethod, ok := s.respBuf.Get(2, true) + if !ok { + return utils.LSMActionPause + } + if verAndMethod[0] != Socks5Version { + return utils.LSMActionCancel + } + s.authRespMethod = int(verAndMethod[1]) + s.respMap = make(analyzer.PropMap) + return utils.LSMActionNext +} + +func (s *socks5Stream) parseSocks5RespAuth() utils.LSMAction { + switch s.authRespMethod { + case AuthNotRequired: + s.respMap["auth"] = analyzer.PropMap{"method": s.authRespMethod} + case AuthPassword: + authResp, ok := s.respBuf.Get(2, true) + if !ok { + return utils.LSMActionPause + } + if authResp[0] != 0x01 { + return utils.LSMActionCancel + } + authStatus := int(authResp[1]) + s.respMap["auth"] = analyzer.PropMap{ + "method": s.authRespMethod, + "status": authStatus, + } + default: + return utils.LSMActionCancel + } + s.respUpdated = true + return utils.LSMActionNext +} + +func (s *socks5Stream) parseSocks5RespConnInfo() utils.LSMAction { + /* preInfo struct + +----+-----+-------+------+-------------+ + |VER | REP | RSV | ATYP | BND.ADDR(1) | + +----+-----+-------+------+-------------+ + */ + preInfo, ok := s.respBuf.Get(5, false) + if !ok { + return utils.LSMActionPause + } + + // verify socks version + if preInfo[0] != Socks5Version { + return utils.LSMActionCancel + } + + var pktLen int + switch int(preInfo[3]) { + case AddrTypeIPv4: + pktLen = 10 + case AddrTypeDomain: + domainLen := int(preInfo[4]) + pktLen = 7 + domainLen + case AddrTypeIPv6: + pktLen = 22 + default: + return utils.LSMActionCancel + } + + pkt, ok := s.respBuf.Get(pktLen, true) + if !ok { + return utils.LSMActionPause + } + + // parse rep + rep := int(pkt[1]) + s.respMap["rep"] = rep + + // parse addr type + addrType := int(pkt[3]) + var addr string + switch addrType { + case AddrTypeIPv4: + addr = net.IPv4(pkt[4], pkt[5], pkt[6], pkt[7]).String() + case AddrTypeDomain: + addr = string(pkt[5 : 5+pkt[4]]) + case AddrTypeIPv6: + addr = net.IP(pkt[4 : 4+net.IPv6len]).String() + default: + return utils.LSMActionCancel + } + s.respMap["addr_type"] = addrType + s.respMap["addr"] = addr + + // parse port + port := int(pkt[pktLen-2])<<8 | int(pkt[pktLen-1]) + s.respMap["port"] = port + s.respUpdated = true + return utils.LSMActionNext +} diff --git a/cmd/root.go b/cmd/root.go index 4baf5b2..8aff027 100644 --- a/cmd/root.go +++ b/cmd/root.go @@ -90,6 +90,7 @@ var analyzers = []analyzer.Analyzer{ &tcp.SSHAnalyzer{}, &tcp.TLSAnalyzer{}, &tcp.TrojanAnalyzer{}, + &tcp.Socks5Analyzer{}, &udp.DNSAnalyzer{}, }