Class: Rex::Proto::Proxy::Socks5::ServerClient

Inherits:
Object
  • Object
show all
Defined in:
lib/rex/proto/proxy/socks5/server_client.rb

Overview

A client connected to the SOCKS5 server.

Constant Summary collapse

AUTH_NONE =
0
AUTH_GSSAPI =
1
AUTH_CREDS =
2
AUTH_NO_ACCEPTABLE_METHODS =
255
AUTH_PROTOCOL_VERSION =
1
AUTH_RESULT_SUCCESS =
0
AUTH_RESULT_FAILURE =
1
COMMAND_CONNECT =
1
COMMAND_BIND =
2
COMMAND_UDP_ASSOCIATE =
3
REPLY_SUCCEEDED =
0
REPLY_GENERAL_FAILURE =
1
REPLY_NOT_ALLOWED =
2
REPLY_NET_UNREACHABLE =
3
REPLY_HOST_UNREACHABLE =
4
REPLY_CONNECTION_REFUSED =
5
REPLY_TTL_EXPIRED =
6
REPLY_CMD_NOT_SUPPORTED =
7
REPLY_ADDRESS_TYPE_NOT_SUPPORTED =
8
HOST =
1
PORT =
2

Instance Method Summary collapse

Constructor Details

#initialize(server, sock, opts = {}) ⇒ ServerClient

Create a new client connected to the server.


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# File 'lib/rex/proto/proxy/socks5/server_client.rb', line 104

def initialize(server, sock, opts={})
  @server        = server
  @lsock         = sock
  @opts          = opts
  @rsock         = nil
  @client_thread = nil
  @mutex         = ::Mutex.new
end

Instance Method Details

#handle_authenticationObject


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# File 'lib/rex/proto/proxy/socks5/server_client.rb', line 137

def handle_authentication
  request = AuthRequestPacket.read(@lsock.get_once)
  if @opts['ServerUsername'].nil? && @opts['ServerPassword'].nil?
    handle_authentication_none(request)
  else
    handle_authentication_creds(request)
  end
end

#handle_authentication_creds(request) ⇒ Object


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# File 'lib/rex/proto/proxy/socks5/server_client.rb', line 146

def handle_authentication_creds(request)
  unless request.supported_methods.include? AUTH_CREDS
    raise "Invalid SOCKS5 request packet received (no supported authentication methods)."
  end
  response = AuthResponsePacket.new
  response.chosen_method = AUTH_CREDS
  @lsock.put(response.to_binary_s)

  version = @lsock.read(1)
  raise "Invalid SOCKS5 authentication packet received." unless version.unpack('C').first == 0x01

  username_length = @lsock.read(1).unpack('C').first
  username        = @lsock.read(username_length)

  password_length = @lsock.read(1).unpack('C').first
  password        = @lsock.read(password_length)

  #  +-----+--------+
  #  | VER | STATUS |
  #  +-----+--------+  VERSION: 0x01
  #  | 1   | 1      |  STATUS:  0x00=SUCCESS, otherwise FAILURE
  #  +-----+--------+
  if username == @opts['ServerUsername'] && password == @opts['ServerPassword']
    raw = [ AUTH_PROTOCOL_VERSION, AUTH_RESULT_SUCCESS ].pack ('CC')
    ilog("SOCKS5: Successfully authenticated")
    @lsock.put(raw)
  else
    raw = [ AUTH_PROTOCOL_VERSION, AUTH_RESULT_FAILURE ].pack ('CC')
    @lsock.put(raw)
    raise "Invalid SOCKS5 credentials provided"
  end
end

#handle_authentication_none(request) ⇒ Object


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# File 'lib/rex/proto/proxy/socks5/server_client.rb', line 179

def handle_authentication_none(request)
  unless request.supported_methods.include? AUTH_NONE
    raise "Invalid SOCKS5 request packet received (no supported authentication methods)."
  end
  response = AuthResponsePacket.new
  response.chosen_method = AUTH_NONE
  @lsock.put(response.to_binary_s)
end

#handle_commandObject


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# File 'lib/rex/proto/proxy/socks5/server_client.rb', line 188

def handle_command
  request = RequestPacket.read(@lsock.get_once)
  response = nil
  case request.command
    when COMMAND_BIND
      response = handle_command_bind(request)
    when COMMAND_CONNECT
      response = handle_command_connect(request)
    when COMMAND_UDP_ASSOCIATE
      response = handle_command_udp_associate(request)
  end
  @lsock.put(response.to_binary_s) unless response.nil?
end

#handle_command_bind(request) ⇒ Object


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# File 'lib/rex/proto/proxy/socks5/server_client.rb', line 202

def handle_command_bind(request)
  # create a server socket for this request
  params = {
    'LocalHost' => request.address_type == Address::ADDRESS_TYPE_IPV6 ? '::' : '0.0.0.0',
    'LocalPort' => 0,
  }
  params['Context'] = @server.opts['Context'] if @server.opts.has_key?('Context')
  bsock = Rex::Socket::TcpServer.create(params)

  # send back the bind success to the client
  response              = ResponsePacket.new
  response.command      = REPLY_SUCCEEDED
  response.address      = bsock.getlocalname[HOST]
  response.port         = bsock.getlocalname[PORT]
  @lsock.put(response.to_binary_s)

  # accept a client connection (2 minute timeout as per the socks4a spec)
  begin
    ::Timeout.timeout(120) do
      @rsock = bsock.accept
    end
  rescue ::Timeout::Error
    raise "Timeout reached on accept request."
  end

  # close the listening socket
  bsock.close

  setup_tcp_relay
  response              = ResponsePacket.new
  response.command      = REPLY_SUCCEEDED
  response.address      = @rsock.peerhost
  response.port         = @rsock.peerport
  response
end

#handle_command_connect(request) ⇒ Object


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# File 'lib/rex/proto/proxy/socks5/server_client.rb', line 238

def handle_command_connect(request)
  # perform the connection request
  params = {
    'PeerHost' => request.address,
    'PeerPort' => request.port,
  }
  params['Context'] = @server.opts['Context'] if @server.opts.has_key?('Context')
  @rsock = Rex::Socket::Tcp.create(params)

  setup_tcp_relay
  response              = ResponsePacket.new
  response.command      = REPLY_SUCCEEDED
  response.address      = @rsock.getlocalname[HOST].split('-')[-1]
  response.port         = @rsock.getlocalname[PORT]
  response
end

#handle_command_udp_associate(request) ⇒ Object


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# File 'lib/rex/proto/proxy/socks5/server_client.rb', line 255

def handle_command_udp_associate(request)
  response              = ResponsePacket.new
  response.command      = REPLY_CMD_NOT_SUPPORTED
  response
end

#setup_tcp_relayObject

Setup the TcpRelay between lsock and rsock.


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# File 'lib/rex/proto/proxy/socks5/server_client.rb', line 264

def setup_tcp_relay
  # setup the two way relay for full duplex io
  @lsock.extend(TcpRelay)
  @rsock.extend(TcpRelay)
  # start the socket relays...
  @lsock.relay(self, @rsock)
  @rsock.relay(self, @lsock)
end

#startObject

Start handling the client connection.


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# File 'lib/rex/proto/proxy/socks5/server_client.rb', line 115

def start
  # create a thread to handle this client request so as to not block the socks5 server
  @client_thread = Rex::ThreadFactory.spawn("SOCKS5ProxyClient", false) do
    begin
      @server.add_client(self)
      # get the initial client request packet
      handle_authentication

      # handle the request
      handle_command
    rescue => exception
      # respond with a general failure to the client
      response         = ResponsePacket.new
      response.command = REPLY_GENERAL_FAILURE
      @lsock.put(response.to_binary_s)

      wlog("Client.start - #{$!}")
      self.stop
    end
  end
end

#stopObject

Stop handling the client connection.


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# File 'lib/rex/proto/proxy/socks5/server_client.rb', line 276

def stop
  @mutex.synchronize do
    unless @closed
      begin
        @lsock.close if @lsock
      rescue
      end

      begin
        @rsock.close if @rsock
      rescue
      end

      @client_thread.kill if @client_thread and @client_thread.alive?
      @server.remove_client(self)
      @closed = true
    end
  end
end