metasploit-framework/tools/exploit/nasm_shell.rb

57 lines
1.3 KiB
Ruby
Executable File

#!/usr/bin/env ruby
#
# $Id$
#
# This tool provides an easy way to see what opcodes are associated with
# certain x86 instructions by making use of nasm if it is installed and
# reachable through the PATH environment variable.
#
# $Revision$
#
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'
$:.unshift(ENV['MSF_LOCAL_LIB']) if ENV['MSF_LOCAL_LIB']
require 'rex'
require 'rex/ui'
# Check to make sure nasm is installed and reachable through the user's PATH.
begin
Rex::Assembly::Nasm.check
rescue RuntimeError
puts "#{$!}"
exit
end
bits = ARGV.length > 0 ? ARGV[0].to_i : 32
if ! [16, 32, 64].include?(bits) then
puts "#{bits} bits not supported"
exit 1
end
# Start a pseudo shell and dispatch lines to be assembled and then
# disassembled.
shell = Rex::Ui::Text::PseudoShell.new("%bldnasm%clr")
shell.init_ui(Rex::Ui::Text::Input::Stdio.new, Rex::Ui::Text::Output::Stdio.new)
shell.run { |line|
line.gsub!(/(\r|\n)/, '')
line.gsub!(/\\n/, "\n")
break if (line =~ /^(exit|quit)/i)
begin
puts(Rex::Assembly::Nasm.disassemble(
Rex::Assembly::Nasm.assemble(line, bits), bits))
rescue RuntimeError
puts "Error: #{$!}"
end
}