# -*- coding: binary -*-
require 'rex/proto/sunrpc'

module Msf

###
#
# This mixin provides utility methods for interacting with a SunRPC service on
# a remote machine.  These methods may generally be useful in the context of
# exploitation.  This mixin extends the Tcp exploit mixin. Only one SunRPC
# service can be accessed at a time using this class.
#
# http://www.ietf.org/rfc/rfc1057.txt
#
###
module Exploit::Remote::SunRPC
  include Exploit::Remote::Tcp

  XDR = Rex::Encoder::XDR

  MSG_ACCEPTED = 0
  SUCCESS = 0		# RPC executed successfully
  PROG_UMAVAIL = 1	# Remote hasn't exported program
  PROG_MISMATCH = 2	# Remote can't support version #
  PROC_UNAVAIL = 3	# Program can't support procedure
  GARBAGE_ARGS = 4	# Procedure can't decode params'
  SYSTEM_ERR = 5    # System encountered some error

  def initialize(info = {})
    super

    register_evasion_options(
      [
        OptBool.new('ONCRPC::tcp_request_fragmentation', [false, 'Enable fragmentation of TCP ONC/RPC requests', 'false']),
      ], Msf::Exploit::Remote::SunRPC
    )


    register_advanced_options(
      [
        OptInt.new('TIMEOUT', [true, 'Number of seconds to wait for responses to RPC calls', 5])
        # XXX: Use portmapper to do call - Direct portmap to make the request to the program portmap_req
      ], Msf::Exploit::Remote::SunRPC)

    register_options(
      [
        # XXX: XPORT
        Opt::RHOST,
        Opt::RPORT(111),
      ], Msf::Exploit::Remote::SunRPC
    )
  end

  def sunrpc_create(protocol, program, version, time_out = timeout)
    self.rpcobj = Rex::Proto::SunRPC::Client.new(
      :rhost => rhost,
      :rport => rport.to_i,
      :proto => protocol,
      :program => program,
      :timeout => time_out,
      :version => version,
      :context => {
        'Msf'        => framework,
        'MsfExploit' => self,
      }
    )

    if datastore['ONCRPC::tcp_request_fragmentation'] == true
      self.rpcobj.should_fragment = 1
    end

    ret = rpcobj.create
    raise ::Rex::Proto::SunRPC::RPCError, "#{rhost}:#{rport} - SunRPC - No response to Portmap request" unless ret

    arr = XDR.decode!(ret, Integer, Integer, Integer, String, Integer, Integer)
    if arr[1] != MSG_ACCEPTED || arr[4] != SUCCESS || arr[5] == 0
      err = "#{rhost}:#{rport} - SunRPC - Portmap request failed: "
      err << 'Message not accepted'  if arr[1] != MSG_ACCEPTED
      err << 'RPC did not execute'   if arr[4] != SUCCESS
      err << 'Program not available' if arr[5] == 0
      raise ::Rex::Proto::SunRPC::RPCError, err
    end

    rpcobj.pport = arr[5]
  end

  def sunrpc_call(proc, buf, timeout = timeout)
    ret = rpcobj.call(proc, buf, timeout)
    raise ::Rex::Proto::SunRPC::RPCError, "#{rhost}:#{rport} - SunRPC - No response to SunRPC call for procedure: #{proc}" unless ret

    arr = Rex::Encoder::XDR.decode!(ret, Integer, Integer, Integer, String, Integer)
    if arr[1] != MSG_ACCEPTED || arr[4] != SUCCESS
      progname = progresolv(rpcobj.program)
      err = "SunRPC call for program #{rpcobj.program} [#{progname}], procedure #{proc}, failed: "
      if (arr[1] != MSG_ACCEPTED)
        err << 'Message not accepted'
      elsif (arr[4] and arr[4] != SUCCESS)
        case arr[4]
          when PROG_UMAVAIL  then err << "Program Unavailable"
          when PROG_MISMATCH then err << "Program Version Mismatch"
          when PROC_UNAVAIL  then err << "Procedure Unavailable"
          when GARBAGE_ARGS  then err << "Garbage Arguments"
          when SYSTEM_ERR    then err << "System Error"
          else err << "Unknown Error"
        end
      end
      raise ::Rex::Proto::SunRPC::RPCError, "#{rhost}:#{rport} - SunRPC - #{err}"
    end
    return ret
  end

  def sunrpc_callsock
    self.rpcobj.call_sock
  end

  def sunrpc_destroy
    rpcobj.destroy
    rpcobj = nil
  end

  def sunrpc_authnull(*args)
    rpcobj.authnull_create(*args)
  end

  def sunrpc_authunix(*args)
    rpcobj.authunix_create(*args)
  end

  # XXX: Incomplete. Just moved from Rex::Proto::SunRPC::Client
  def portmap_qry()
    ret = portmap_req()
    arr = Rex::Encoder::XDR.decode!(ret, Integer, Integer, Integer, String, Integer)
    if arr[1] != MSG_ACCEPTED || arr[4] != SUCCESS || arr[5] == 0
      progname = progresolv(rpcobj.program)
      err = "Query for program #{rpcobj.program} [#{progname}] failed: "
      case arr[4]
        when PROG_UMAVAIL  then err << "Program Unavailable"
        when PROG_MISMATCH then err << "Program Version Mismatch"
        when PROC_UNAVAIL  then err << "Procedure Unavailable"
        when GARBAGE_ARGS  then err << "Garbage Arguments"
        else err << "Unknown Error"
      end
      raise ::Rex::Proto::SunRPC::RPCError, "#{rhost}:#{rport} - SunRPC - #{err}"
    end

    return ret
  end

  def progresolv(number)
    names = File.join(Msf::Config.data_directory, "wordlists", "rpc_names.txt")
    File.open(names, "rb").each_line do |line|
      next if line.empty? || line =~ /^\s*#/

      if line =~ /^(\S+?)\s+(\d+)/ && number == $2.to_i
        return $1
      end
    end

    return "UNKNOWN-#{number}"
  end

  # Returns the time that this module will wait for RPC responses, in seconds
  def timeout
    datastore['TIMEOUT']
  end

  # Used to track the last SunRPC context
  attr_accessor	:rpcobj
end

end