##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##

require 'rex/encoder/alpha2/unicode_mixed'

class MetasploitModule < Msf::Encoder::Alphanum
  Rank = ManualRanking

  def initialize
    super(
      'Name'             => "Alpha2 Alphanumeric Unicode Mixedcase Encoder",
      'Description'      => %q{
        Encodes payloads as unicode-safe mixedcase text.  This encoder uses
        SkyLined's Alpha2 encoding suite.
      },
      'Author'           => [ 'pusscat', 'skylined' ],
      'Arch'             => ARCH_X86,
      'License'          => BSD_LICENSE,
      'EncoderType'      => Msf::Encoder::Type::AlphanumUnicodeMixed,
      'Decoder'          =>
        {
          'BlockSize' => 1,
        })
  end

  #
  # Returns the decoder stub that is adjusted for the size of the buffer
  # being encoded.
  #
  def decoder_stub(state)
    reg    = datastore['BufferRegister']
    offset = datastore['BufferOffset'].to_i || 0
    if (not reg)
      raise EncodingError, "Need BufferRegister"
    end
    Rex::Encoder::Alpha2::UnicodeMixed::gen_decoder(reg, offset)
  end

  #
  # Encodes a one byte block with the current index of the length of the
  # payload.
  #
  def encode_block(state, block)
    Rex::Encoder::Alpha2::UnicodeMixed::encode_byte(block.unpack('C')[0], state.badchars)
  end

  #
  # Tack on our terminator
  #
  def encode_end(state)
    state.encoded += Rex::Encoder::Alpha2::UnicodeMixed::add_terminator()
  end

  #
  # Returns the unicode version of the supplied buffer.
  #
  def to_native(buffer)
    Rex::Text.to_unicode(buffer)
  end
end