msfelfscan

#!/usr/bin/env ruby
# -*- coding: binary -*-
#
# $Id$
# $Revision$
#

msfbase = __FILE__
while File.symlink?(msfbase)
  msfbase = File.expand_path(File.readlink(msfbase), File.dirname(msfbase))
end

$:.unshift(File.expand_path(File.join(File.dirname(msfbase), 'lib')))
require 'msfenv'



$:.unshift(ENV['MSF_LOCAL_LIB']) if ENV['MSF_LOCAL_LIB']

require 'rex/elfparsey'
require 'rex/elfscan'
require 'rex/arch/x86'
require 'optparse'

def opt2i(o)
  o.index("0x")==0 ? o.hex : o.to_i
end

opt = OptionParser.new

opt.banner = "Usage: #{$PROGRAM_NAME} [mode] <options> [targets]"
opt.separator('')
opt.separator('Modes:')

worker = nil
param = {}

opt.on('-j', '--jump [regA,regB,regC]', 'Search for jump equivalent instructions') do |t|
  # take csv of register names (like eax,ebx) and convert
  # them to an array of register numbers
  regnums = t.split(',').collect { |o|
    begin
      Rex::Arch::X86.reg_number(o)
    rescue
      puts "Invalid register \"#{o}\""
      exit(1)
    end
  }
  worker = Rex::ElfScan::Scanner::JmpRegScanner
  param['args'] = regnums
end

opt.on('-p', '--poppopret', 'Search for pop+pop+ret combinations') do |t|
  worker = Rex::ElfScan::Scanner::PopPopRetScanner
  param['args'] = t
end

opt.on('-r', '--regex [regex]', 'Search for regex match') do |t|
  worker = Rex::ElfScan::Scanner::RegexScanner
  param['args'] = t
end

opt.on('-a', '--analyze-address [address]', 'Display the code at the specified address') do |t|
  worker = Rex::ElfScan::Search::DumpRVA
  param['args'] = opt2i(t)
end

opt.on('-b', '--analyze-offset [offset]', 'Display the code at the specified offset') do |t|
  worker = Rex::ElfScan::Search::DumpOffset
  param['args'] = opt2i(t)
end

opt.separator('')
opt.separator('Options:')

opt.on('-A', '--after [bytes]', 'Number of bytes to show after match (-a/-b)') do |t|
  param['after'] = opt2i(t)
end

opt.on('-B', '--before [bytes]', 'Number of bytes to show before match (-a/-b)') do |t|
  param['before'] = opt2i(t)
end

opt.on('-D', '--disasm', 'Disassemble the bytes at this address') do |t|
  param['disasm'] = true
end

opt.on('-I', '--image-base [address]', 'Specify an alternate ImageBase') do |t|
  param['imagebase'] = opt2i(t)
end

opt.on_tail("-h", "--help", "Show this message") do
  puts opt
  exit(1)
end

begin
  opt.parse!
rescue OptionParser::InvalidOption
  puts "Invalid option, try -h for usage"
  exit(1)
end

if (! worker)
  puts opt
  exit(1)
end

ARGV.each do |file|

  param['file'] = file

  begin
    elf = Rex::ElfParsey::Elf.new_from_file(file, true)
  rescue Rex::ElfParsey::ElfHeaderError
    if $!.message == 'Invalid magic number'
      $stderr.puts("Skipping #{file}: #{$!}")
      next
    end
    raise $!
  rescue Errno::ENOENT
    $stderr.puts("File does not exist: #{file}")
    next
  end

  if (param['imagebase'])
    elf.base_addr = param['imagebase'];
  end

  o = worker.new(elf)
  o.scan(param)

  elf.close

end