pattern.py

#! /usr/local/bin/python
import sys
import string
import re
import argparse

# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:

# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.

# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.

# USAGE:
# $ ./pattern.py 233
# Aa0Aa1Aa2Aa3Aa4Aa5Aa6Aa7Aa8Aa9Ab0Ab1Ab2Ab3Ab4Ab5Ab6Ab7Ab8Ab9Ac0Ac1Ac2Ac3Ac4Ac5Ac6Ac7Ac8Ac9Ad0Ad1Ad2Ad3Ad4Ad5Ad6Ad7Ad8Ad9Ae0Ae1Ae2Ae3Ae4Ae5Ae6Ae7Ae8Ae9Af0Af1Af2Af3Af4Af5Af6Af7Af8Af9Ag0Ag1Ag2Ag3Ag4Ag5Ag6Ag7Ag8Ag9Ah0Ah1Ah2Ah3Ah4Ah5Ah6Ah
# $ ./pattern.py --offset 0x63413563 233
# 76

parser = argparse.ArgumentParser(description='Find offset from string')
# It is imperative to provide original pattern's length along with the offset.
parser.add_argument('--offset', action='store', dest='offsetStr', help='Find the offset for given length of pattern')
parser.add_argument('lengthOfString', help='Generate pattern of this length')

alphabets = string.ascii_lowercase
alpha_Caps = string.ascii_uppercase

def makePat(lenReq):
	pattern = ''
	lenReq = int(lenReq)
	for capA in alpha_Caps:
		for alpha in alphabets:
			for nums in range(0,10):
				pattern += capA + alpha + str(nums)
				if len(pattern) >= lenReq:
					return pattern[:lenReq]
	return pattern

def findOffset(hexStr, lenReq):
	pattern = makePat(lenReq)
	hexNum = hexStr[2:]
	subPattern = bytearray.fromhex(hexNum).decode()
	subPattern = subPattern[::-1]
	print pattern.find(subPattern)

if __name__ == "__main__":
	args = parser.parse_args()
	if args.offsetStr:
		findOffset(args.offsetStr, args.lengthOfString)
	else:
		print makePat(args.lengthOfString)