Method: Rex::Proto::DCERPC::Response#parse

Defined in:
lib/rex/proto/dcerpc/response.rb

#parse(body = '') ⇒ Object

Parse the contents of a DCERPC response packet and fill out all the fields



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# File 'lib/rex/proto/dcerpc/response.rb', line 45

def parse(body = '')
  self.raw = self.raw + body
  self.type = self.raw[2,1].unpack('C')[0]

  uuid = Rex::Proto::DCERPC::UUID
  data = self.raw


  if(not data)
    raise Rex::Proto::DCERPC::Exceptions::InvalidPacket, 'DCERPC response packet is incomplete'
  end

  # BIND_ACK == 12, ALTER_CONTEXT_RESP == 15
  if (self.type == 12 or self.type == 15)

    # Decode most of the DCERPC header
    self.vers_major,
    self.vers_minor,
    trash,
    self.flags,
    self.data_rep,
    self.frag_len,
    self.auth_len,
    self.call_id,
    self.max_frag_xmit,
    self.max_frag_recv,
    self.assoc_group,
    self.sec_addr_len = data.unpack('CCCCNvvVvvVv')


    if(not self.frag_len or data.length < self.frag_len)
      raise Rex::Proto::DCERPC::Exceptions::InvalidPacket, 'DCERPC response packet is incomplete'
    end

    # Keep an offset into the packet handy
    x = 0

    # XXX This is still somewhat broken (4 digit ports)
    self.sec_addr = data[26, self.sec_addr_len]

    # Move the pointer into the packet forward
    x += 26 + self.sec_addr_len

    # Align the pointer on a dword boundary
    while (x % 4 != 0)
      x += 1
    end

    # Figure out how many results we have (multiple-context binds)
    self.num_results = data[ x, 4 ].unpack('V')[0]

    # Move the pointer to the ack_result[0] offset
    x += 4

    # Initialize the ack_result index
    ack = 0

    # Scan through all results and add them to the result arrays
    while ack < self.num_results
      self.ack_result[ack] = data[ x + 0, 2 ].unpack('v')[0]
      self.ack_reason[ack] = data[ x + 2, 2 ].unpack('v')[0]
      self.ack_xfer_syntax_uuid[ack] = uuid.uuid_unpack(data[ x + 4, 16 ])
      self.ack_xfer_syntax_vers[ack] = data[ x + 20, 4 ].unpack('V')[0]
      x += 24
      ack += 1
    end

    # End of BIND_ACK || ALTER_CONTEXT_RESP
  end

  # BIND_NACK == 13
  if (self.type == 13)

    # Decode most of the DCERPC header
    self.vers_major,
    self.vers_minor,
    trash,
    self.flags,
    self.data_rep,
    self.frag_len,
    self.auth_len,
    self.call_id,
    self.nack_reason = data.unpack('CCCCNvvVv')
  end

  # RESPONSE == 2
  if (self.type == 2)

    # Decode the DCERPC response header
    self.vers_major,
    self.vers_minor,
    trash,
    self.flags,
    self.data_rep,
    self.frag_len,
    self.auth_len,
    self.call_id,
    self.alloc_hint,
    self.context_id,
    self.cancel_cnt = data.unpack('CCCCNvvVVvC')

    # Error out if the whole header was not read
    if !(self.alloc_hint and self.context_id and self.cancel_cnt)
      raise Rex::Proto::DCERPC::Exceptions::InvalidPacket, 'DCERPC response packet is incomplete'
    end

    # Put the application data into self.stub_data
    self.stub_data = data[data.length - self.alloc_hint, 0xffff]
    # End of RESPONSE
  end

  # FAULT == 3
  if (self.type == 3)

    # Decode the DCERPC response header
    self.vers_major,
    self.vers_minor,
    trash,
    self.flags,
    self.data_rep,
    self.frag_len,
    self.auth_len,
    self.call_id,
    self.alloc_hint,
    self.context_id,
    self.cancel_cnt,
    trash,
    self.status = data.unpack('CCCCNvvVVvCCV')

    # Put the application data into self.stub_data
    self.stub_data = data[data.length - self.alloc_hint, 0xffff]
    # End of FAULT
  end

end