Class: Rex::Services::LocalRelay

Inherits:
Object
  • Object
show all
Includes:
Rex::Service
Defined in:
lib/rex/services/local_relay.rb

Overview

This service acts as a local TCP relay whereby clients can connect to a local listener that forwards to an arbitrary remote endpoint. Interaction with the remote endpoint socket requires that it implement the Rex::IO::Stream interface.

Defined Under Namespace

Modules: Stream, StreamServer Classes: Relay, ReverseRelay

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Rex::Service

#cleanup, #deref

Constructor Details

#initialize ⇒ LocalRelay

Initializes the local tcp relay monitor.



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# File 'lib/rex/services/local_relay.rb', line 149

def initialize
  self.relays       = Hash.new
  self.rfds         = Array.new
  self.rev_chans    = Array.new
  self.relay_thread = nil
  self.relay_mutex  = Mutex.new
end

Instance Attribute Details

#relay_mutex ⇒ Object (protected)

Returns the value of attribute relay_mutex.



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# File 'lib/rex/services/local_relay.rb', line 335

def relay_mutex
  @relay_mutex
end

#relay_thread ⇒ Object (protected)

Returns the value of attribute relay_thread.



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# File 'lib/rex/services/local_relay.rb', line 335

def relay_thread
  @relay_thread
end

#relays ⇒ Object (protected)

Returns the value of attribute relays.



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# File 'lib/rex/services/local_relay.rb', line 335

def relays
  @relays
end

#rev_chans ⇒ Object (protected)

Returns the value of attribute rev_chans.



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# File 'lib/rex/services/local_relay.rb', line 336

def rev_chans
  @rev_chans
end

#rfds ⇒ Object (protected)

Returns the value of attribute rfds.



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# File 'lib/rex/services/local_relay.rb', line 336

def rfds
  @rfds
end

Class Method Details

.hardcore_alias(*args) ⇒ Object

Returns the hardcore alias for the local relay service.



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# File 'lib/rex/services/local_relay.rb', line 166

def self.hardcore_alias(*args)
  "__#{args}"
end

Instance Method Details

#accept_relay_conn(srvfd) ⇒ Object (protected)

Accepts a client connection on a local relay.



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# File 'lib/rex/services/local_relay.rb', line 425

def accept_relay_conn(srvfd)
  relay = srvfd.relay

  begin
    dlog("Accepting relay client connection...", 'rex', LEV_3)

    # Accept the child connection
    lfd = srvfd.accept
    dlog("Got left side of relay: #{lfd}", 'rex', LEV_3)

    # Call the relay's on_local_connection method which should return a
    # remote connection on success
    rfd = srvfd.on_local_connection(relay, lfd)

    dlog("Got right side of relay: #{rfd}", 'rex', LEV_3)
  rescue
    wlog("Failed to get remote half of local connection on relay #{relay.name}: #{$!}", 'rex')
    lfd.close
    return
  end

  # If we have both sides, then we rock.  Extend the instances, associate
  # them with the relay, associate them with each other, and add them to
  # the list of polling file descriptors
  if lfd && rfd
    lfd.extend(Stream)
    rfd.extend(Stream)

    lfd.relay = relay
    rfd.relay = relay

    lfd.other_stream = rfd
    rfd.other_stream = lfd

    self.rfds << lfd
    self.rfds << rfd
  else
    # Otherwise, we don't have both sides, we'll close them.
    close_relay_conn(lfd)
  end
end

#accept_reverse_relay(rrfd) ⇒ Object (protected)

Attempt to accept a new reverse connection on the given reverse relay handle.



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# File 'lib/rex/services/local_relay.rb', line 397

def accept_reverse_relay(rrfd)

  rfd = rrfd.accept_nonblock

  return unless rfd

  lfd = Rex::Socket::Tcp.create(
    'PeerHost'  => rrfd.relay.opts['PeerHost'],
    'PeerPort'  => rrfd.relay.opts['PeerPort'],
    'Timeout'   => 5
  )

  rfd.extend(Stream)
  lfd.extend(Stream)

  rfd.relay = rrfd.relay
  lfd.relay = rrfd.relay

  self.rfds << lfd
  self.rfds << rfd

  rfd.other_stream = lfd
  lfd.other_stream = rfd
end

#alias ⇒ Object

Returns the alias for this service.



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# File 'lib/rex/services/local_relay.rb', line 173

def alias
  super || "Local Relay"
end

#close_relay(relay) ⇒ Object (protected)

Closes an cleans up a specific relay



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# File 'lib/rex/services/local_relay.rb', line 341

def close_relay(relay)

  if relay.kind_of?(ReverseRelay)
    self.rev_chans.delete(relay.channel)
  else
    self.rfds.delete(relay.listener)
  end

  self.relays.delete(relay.name)

  begin
    relay.shutdown
    relay.close
  rescue IOError
  end
end

#close_relay_conn(fd) ⇒ Object (protected)

Closes a specific relay connection without tearing down the actual relay itself.



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# File 'lib/rex/services/local_relay.rb', line 362

def close_relay_conn(fd)
  relay = fd.relay
  ofd   = fd.other_stream

  self.rfds.delete(fd)

  begin
    if relay.on_conn_close_proc
      relay.on_conn_close_proc.call(fd)
    end

    fd.shutdown
    fd.close
  rescue IOError
  end

  if ofd
    self.rfds.delete(ofd)

    begin
      if (relay.on_conn_close_proc)
        relay.on_conn_close_proc.call(ofd)
      end

      ofd.shutdown
      ofd.close
    rescue IOError
    end
  end
end

#each_tcp_relay(&block) ⇒ Object

Enumerate each TCP relay



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# File 'lib/rex/services/local_relay.rb', line 320

def each_tcp_relay(&block)
  self.relays.each_pair { |name, relay|
    next if (relay.opts['__RelayType'] != 'tcp')

    yield(
      relay.opts['LocalHost'] || '0.0.0.0',
      relay.opts['LocalPort'],
      relay.opts['PeerHost'],
      relay.opts['PeerPort'],
      relay.opts)
  }
end

#monitor_relays ⇒ Object (protected)

Monitors the relays for data and passes it in both directions.



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# File 'lib/rex/services/local_relay.rb', line 470

def monitor_relays
  begin
    # Helps with latency
    Thread.current.priority = 2

    # See if we have any new connections on the existing reverse port
    # forward relays
    rev_chans.each do |rrfd|
      accept_reverse_relay(rrfd)
    end

    # Poll all the streams...
    begin
      socks = Rex::ThreadSafe.select(rfds, nil, nil, 0.25)
    rescue StreamClosedError => e
      dlog("monitor_relays: closing stream #{e.stream}", 'rex', LEV_3)

      # Close the relay connection that is associated with the stream
      # closed error
      if e.stream.kind_of?(Stream)
        close_relay_conn(e.stream)
      end

      dlog("monitor_relays: closed stream #{e.stream}", 'rex', LEV_3)

      next
    rescue => e
      elog("Error in #{self} monitor_relays select:", 'rex', error: e)
      return
    end

    # If socks is nil, go again.
    next unless socks

    # Process read-ready file descriptors, if any.
    socks[0].each { |rfd|

      # If this file descriptor is a server, accept the connection
      if (rfd.kind_of?(StreamServer))
        accept_relay_conn(rfd)
      else
        # Otherwise, it's a relay connection, read data from one side
        # and write it to the other
        begin
          # Pass the data onto the other fd, most likely writing it.
          data = rfd.sysread(65536)
          rfd.other_stream.on_other_data(data)
        # If we catch an error, close the connection
        rescue ::Exception => e
          elog("Error in #{self} monitor_relays read", 'rex', error: e)
          close_relay_conn(rfd)
        end
      end

    } if (socks[0])

  end while true
end

#start ⇒ Object

Starts the thread that monitors the local relays.



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# File 'lib/rex/services/local_relay.rb', line 180

def start
  if (!self.relay_thread)
    self.relay_thread = Rex::ThreadFactory.spawn("LocalRelay", false) {
      begin
        monitor_relays
      rescue ::Exception => e
        elog("Error in #{self} monitor_relays", 'rex', error: e)
      end
    }
  end
end

#start_relay(stream_server, name, opts = {}) ⇒ Object

Starts a local relay on the supplied local port. This listener will call the supplied callback procedures when various events occur.



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# File 'lib/rex/services/local_relay.rb', line 275

def start_relay(stream_server, name, opts = {})
  # Create a Relay instance with the local stream and remote stream
  relay = Relay.new(name, stream_server, opts)

  # Extend the stream_server so that we can associate it with this relay
  stream_server.extend(StreamServer)
  stream_server.relay = relay

  # Add the stream associations the appropriate lists and hashes
  self.relay_mutex.synchronize {
    self.relays[name] = relay

    self.rfds << stream_server
  }
  relay
end

#start_reverse_tcp_relay(channel, opts = {}) ⇒ Object

Start a new active listener on the victim ready for reverse connections.



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# File 'lib/rex/services/local_relay.rb', line 224

def start_reverse_tcp_relay(channel, opts = {})
  opts['__RelayType'] = 'tcp'
  opts['Reverse'] = true

  name = "Reverse-#{opts['LocalPort']}"

  relay = ReverseRelay.new(name, channel, opts)

  # dirty hack to get "relay" support?
  channel.extend(StreamServer)
  channel.relay = relay

  self.relay_mutex.synchronize {
    self.relays[name] = relay
    self.rev_chans << channel
  }
  relay
end

#start_tcp_relay(lport, opts = {}) ⇒ Object

Starts a local TCP relay.



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# File 'lib/rex/services/local_relay.rb', line 253

def start_tcp_relay(lport, opts = {})
  # Make sure our options are valid
  if ((opts['PeerHost'] == nil or opts['PeerPort'] == nil) and (opts['Stream'] != true))
    raise ArgumentError, "Missing peer host or peer port.", caller
  end

  listener = Rex::Socket.create_tcp_server(
    'LocalHost' => opts['LocalHost'],
    'LocalPort' => lport)

  _, lhost, lport = listener.getlocalname()
  opts['LocalHost']   = lhost
  opts['LocalPort']   = lport
  opts['__RelayType'] = 'tcp'

  start_relay(listener, lport.to_s + opts['LocalHost'], opts)
end

#stop ⇒ Object

Stops the thread that monitors the local relays and destroys all listeners, both local and remote.



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# File 'lib/rex/services/local_relay.rb', line 196

def stop
  if (self.relay_thread)
    self.relay_thread.kill
    self.relay_thread = nil
  end

  self.relay_mutex.synchronize {
    self.relays.delete_if { |k, v|
      v.shutdown
      v.close
      true
    }
  }

  # make sure we kill off active sockets when we shut down
  while self.rfds.length > 0
    close_relay_conn(self.rfds.shift) rescue nil
  end

  # we can safely clear the channels array because all of the
  # reverse relays were closed down
  self.rev_chans.clear
  self.relays.clear
end

#stop_relay(name) ⇒ Object

Stops a relay with a given name.



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# File 'lib/rex/services/local_relay.rb', line 302

def stop_relay(name)
  rv = false

  self.relay_mutex.synchronize {
    relay = self.relays[name]

    if relay
      close_relay(relay)
      rv = true
    end
  }

  rv
end

#stop_reverse_tcp_relay(rport) ⇒ Object

Stop an active reverse port forward.



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# File 'lib/rex/services/local_relay.rb', line 246

def stop_reverse_tcp_relay(rport)
  stop_relay("Reverse-#{rport}")
end

#stop_tcp_relay(lport, lhost = nil) ⇒ Object

Stops relaying on a given local port.



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# File 'lib/rex/services/local_relay.rb', line 295

def stop_tcp_relay(lport, lhost = nil)
  stop_relay(lport.to_s + (lhost || '0.0.0.0'))
end