1#!/usr/bin/env python 2 3"""A tool for looking for indirect jumps and calls in x86 binaries. 4 5 Helpful to verify whether or not retpoline mitigations are catching 6 all of the indirect branches in a binary and telling you which 7 functions the remaining ones are in (assembly, etc). 8 9 Depends on llvm-objdump being in your path and is tied to the 10 dump format. 11""" 12 13from __future__ import print_function 14 15import os 16import sys 17import re 18import subprocess 19import optparse 20 21# Look for indirect calls/jmps in a binary. re: (call|jmp).*\* 22def look_for_indirect(file): 23 args = ['llvm-objdump'] 24 args.extend(["-d"]) 25 args.extend([file]) 26 27 p = subprocess.Popen(args=args, stdin=None, stderr=subprocess.PIPE, stdout=subprocess.PIPE) 28 (stdout,stderr) = p.communicate() 29 30 function = "" 31 for line in stdout.splitlines(): 32 if line.startswith(' ') == False: 33 function = line 34 result = re.search('(call|jmp).*\*', line) 35 if result != None: 36 # TODO: Perhaps use cxxfilt to demangle functions? 37 print(function) 38 print(line) 39 return 40 41def main(args): 42 # No options currently other than the binary. 43 parser = optparse.OptionParser("%prog [options] <binary>") 44 (opts, args) = parser.parse_args(args) 45 if len(args) != 2: 46 parser.error("invalid number of arguments: %s" % len(args)) 47 look_for_indirect(args[1]) 48 49if __name__ == '__main__': 50 main(sys.argv) 51