filename_validation.py

#!/usr/bin/env python
# diff

from __future__ import print_function
from unicorn import *
from unicorn.arm_const import *
import binascii
import sys
# code to be emulated

ARM_CODE  = b"\x42\x1E" + \
            b"\x12\xF8\x01\x0F\x80\xB1\x20\xF0\x20\x03\xA3\xF1\x41\x01\x19\x29\xF6\xD9\xA0\xF1\x30\x03\x09\x2B" + \
            b"\xF2\xD9" + \
            b"\x5F\x28" + \
            b"\xF0\xD0" + \
            b"\x2E\x28\xEE\xD0\x6F\xF4\x7A\x70" + \
            b"\x00\x46\x00\x46" #b"\x70\x47\x70\x47" # We can't have bx lr since lr won't be defined, so I changed it to mv r0, r0 (NOP)

# memory address where emulation starts
ADDRESS    = 0x10000
SCRATCH_ADDRESS    = 0x1000

def executeFunction(string):
    code = ARM_CODE
    try:
        # Initialize emulator in thumb mode
        mu = Uc(UC_ARCH_ARM, UC_MODE_THUMB)

        # map 2MB memory for this emulation
        mu.mem_map(ADDRESS, 4 * 1024 * 1024)

        # write machine code to be emulated to memory
        mu.mem_write(ADDRESS, code)

        # map 10K scratch memory for this emulation
        mu.mem_map(SCRATCH_ADDRESS, 10 * 1024)

        # write dummy data to be emulated to memory
        mu.mem_write(SCRATCH_ADDRESS, string)

        # initialize machine registers
        for i in range(UC_ARM_REG_R0, UC_ARM_REG_R12):
            val = mu.reg_write(i, 0)

        mu.reg_write(UC_ARM_REG_R0, SCRATCH_ADDRESS)

        # emulate machine code in infinite time
        mu.emu_start(ADDRESS + 1, ADDRESS + len(code))

        return mu.reg_read(UC_ARM_REG_R0)
    except UcError as e:
        print("ERROR: %s" % e)

if __name__ == '__main__':
    if len(sys.argv) < 2:
        print("Enter a potential file path")
    ret = executeFunction(sys.argv[1])

    if ret != 0:
        print("Failed to validate")
    else:
        print("Passed validation")