92 lines
2.6 KiB
Ruby
92 lines
2.6 KiB
Ruby
#!/usr/bin/env ruby
|
|
# This file is part of Metasm, the Ruby assembly manipulation suite
|
|
# Copyright (C) 2006-2009 Yoann GUILLOT
|
|
#
|
|
# Licence is LGPL, see LICENCE in the top-level directory
|
|
|
|
# modifies the standard ruby class String to add #decode and #encode methods
|
|
# they will respectively disassemble binary data / assemble asm source
|
|
# the default CPU is x86 32bits, change it using eg String.cpu = Metasm::MIPS.new(:big) (mips bigendian)
|
|
#
|
|
# it also defines the toplevel 'asm' method, that will start an interactive
|
|
# assembler shell (type in assembly statements, they are shown assembled in binary escaped form)
|
|
#
|
|
# eg:
|
|
# ruby metasm-shell
|
|
# > nop ; nop
|
|
# "\x90\x90"
|
|
# > exit
|
|
|
|
require 'metasm'
|
|
|
|
class String
|
|
@@cpu = Metasm::Ia32.new
|
|
class << self
|
|
def cpu() @@cpu end
|
|
def cpu=(c)
|
|
c = Metasm.const_get(c).new if c.kind_of? String
|
|
@@cpu=c
|
|
end
|
|
end
|
|
|
|
# encodes the current string as a Shellcode, returns the resulting EncodedData
|
|
def encode_edata
|
|
s = Metasm::Shellcode.assemble @@cpu, self
|
|
s.encoded
|
|
end
|
|
|
|
# encodes the current string as a Shellcode, returns the resulting binary String
|
|
# outputs warnings on unresolved relocations
|
|
def encode
|
|
ed = encode_edata
|
|
if not ed.reloc.empty?
|
|
puts 'W: encoded string has unresolved relocations: ' + ed.reloc.map { |o, r| r.target.inspect }.join(', ')
|
|
end
|
|
ed.fill
|
|
ed.data
|
|
end
|
|
|
|
# decodes the current string as a Shellcode, with specified base address
|
|
# returns the resulting Disassembler
|
|
def decode_blocks(base_addr=0, eip=base_addr)
|
|
sc = Metasm::Shellcode.decode(self, @@cpu)
|
|
sc.base_addr = base_addr
|
|
sc.disassemble(eip)
|
|
end
|
|
|
|
# decodes the current string as a Shellcode, with specified base address
|
|
# returns the asm source equivallent
|
|
def decode(base_addr=0, eip=base_addr)
|
|
decode_blocks(base_addr, eip).to_s
|
|
end
|
|
end
|
|
|
|
# get in interactive assembler mode
|
|
def asm
|
|
puts 'type "exit" or "quit" to quit', 'use ";" for newline', ''
|
|
while (print "asm> " ; $stdout.flush ; l = gets)
|
|
break if %w[quit exit].include? l.chomp
|
|
if l.chomp == 'help'
|
|
puts "Metasm assembly shell: type in opcodes to see their binary form",
|
|
"You can use ';' to type multi-line stuff",
|
|
"e.g. 'nop nop' will display \"\\x90\\x90\""
|
|
next
|
|
end
|
|
|
|
begin
|
|
data = l.gsub(';', "\n")
|
|
next if data.strip.empty?
|
|
data = data.encode
|
|
puts '"' + data.unpack('C*').map { |c| '\\x%02x' % c }.join + '"'
|
|
rescue Metasm::Exception => e
|
|
puts "Error: #{e.class} #{e.message}"
|
|
end
|
|
end
|
|
|
|
puts
|
|
end
|
|
|
|
if __FILE__ == $0
|
|
asm
|
|
end
|