Method: Rex::Poly::LogicalBlock#generate

Defined in:

lib/rex/poly/block.rb

#generate(save_registers = nil, state = nil, badchars = nil) ⇒ Object

Generates the polymorphic buffer that results from this block and any of the blocks that it either directly or indirectly depends on. A list of register numbers to be saved can be passed in as an argument.

This method is not thread safe. To call this method on a single block instance from within multiple threads, be sure to encapsulate the calls inside a locked context.

# File 'lib/rex/poly/block.rb', line 240

def generate(save_registers = nil, state = nil, badchars = nil)
  # Create a localized state instance if one was not supplied.
  state = Rex::Poly::State.new if (state == nil)
  buf   = nil
  cnt   = 0

  # This is a lame way of doing this.  We just try to generate at most 128
  # times until we don't have badchars.  The reason we have to do it this
  # way is because of the fact that badchars can be introduced through
  # block offsetting and register number selection which can't be readily
  # predicted or detected during the generation phase.  In the future we
  # can make this better, but for now this will have to do.
  begin
    buf = do_generate(save_registers, state, badchars)

    if (buf and
        (badchars.nil? or Rex::Text.badchar_index(buf, badchars).nil?))
      break
    end
  end while ((cnt += 1) < 128)

  # If we passed 128 tries, then we can't succeed.
  buf = nil if (cnt >= 128)

  buf
end