How to convert this code from Python version 2 to 3.4?

Question

I’m having a hard time convert the code below for the version 3.4 of Python, the purpose of this code is to encode and decode hexadecimal, in order to create shellcodes.

import binascii, sys, time

RED = '\033[31m'
WHITE = '\033[37m'
RESET = '\033[0;0m'

def main():
    print("shellcode hex encode decoder")
    print("programmer : gunslinger_ <yudha.gunslinger[at]gmail.com>")
    print "what do you want to do ? %sencode%s / %sdecode%s" % (RED, RESET, WHITE, RESET)  
    q = raw_input("=> ")

    if q == "encode":
        inputtype = raw_input("Please input data : ")
        print "shellcode => ",
        for encoded in inputtype:
            print "\b\\x"+encoded.encode("hex"),
            sys.stdout.flush()
            time.sleep(0.5)
            print RESET

    elif q == "decode":
        inputtype = raw_input("Please input data : ")
        cleaninput = inputtype.replace("\\x","")
        print "hex       => ",cleaninput
        print "plaintext => ",
        print "\b"+cleaninput.decode("hex")

    else:
        print "wrong answer ! your choice is %sencode%s or %sdecode%s" % (RED, RESET, WHITE, RESET)
        sys.exit(1)

if __name__ == '__main__':
    main()

That part I didn’t understand:

print "what do you want to do ? %sencode%s / %sdecode%s" % (RED, RESET, WHITE, RESET)  

All right he set the colors on top, and the %sencode%s / %sdecode%s how does it work? I understand he made a %s, at the beginning and at the end of the words encounter and Decode and call with the colors.

q = raw_input("=> ")

He defined the variable and this => something specific in Python 2?

In this part below I understood some parts but not all if someone explain me better I am grateful.

inputtype = raw_input("Please input data : ")
print "shellcode => ",
for encoded in inputtype:
    print "\b\\x"+encoded.encode("hex"),
    sys.stdout.flush()
    time.sleep(0.5)

Personal thank you.

Answer 1

Some changes should be made to the code to work as expected in Python 3.

• In versions prior to Python 3 print was an instruction (statement), from Python 3, it is considered a function, and so some details of the syntax have changed, such as the mandatory use of parentheses, ().

  

• From Python 3, the function built-in raw_input() was renamed for input().

  

• In Python 3 it is not necessary to use the comma at the end to delete a new line.

  

• From the Python 3.4 the methods that dealt with coding and decoding were replaced by the functions of the module codecs.

  Python 3.4, wrong mode:

  b"hello".decode("hex")
  Traceback (most recent call last):
   File "<stdin>", line 1, in <module>
   LookupError: 'hex' is not a text encoding; use codecs.decode() to handle arbitrary codecs
  

  Python 3.4, correct mode:

  >>> from codecs import encode, decode
  >>> encode(b"hello", "hex")
  b'68656c6c6f'
  >>> decode(b"68656c6c6f", "hex")
  b'hello'
  

• That part I didn’t understand:

  print "what do you want to do ? %sencode%s / %sdecode%s" % (RED, RESET, WHITE, RESET)
  

  The four occurrences of the format %s shall be replaced by the values of RED, RESET, WHITE and RESET. The print will print:

  print "what do you want to do ? \033[31mencode\033[0;0m / \033[37mdecode\033[0;0m"
  

  This will print on the screen words with a different color, other color combinations can be seen here.

• q = raw_input("=> ") -> he defined the variable and this => serial something specific in python 2

  The => is the text that will be displayed and will receive the user input.

• In this part below I understood some parts but not all if someone explain me better I am grateful.

  inputtype = raw_input("Please input data : ") # Recebe a entrada do usuário
  print "shellcode => ",                        # Imprime "shellcode =>" e elimina a nova linha
  for encoded in inputtype:                     # Percorre cada letra da variável "inputtype"
      print "\b\\x"+encoded.encode("hex"),
      sys.stdout.flush()                        # Imprime diretamente na saída padrão "stdout"
      time.sleep(0.5)                           # Espera 30s
  

The code converted for Python 3 should look like this:

import sys, time, binascii
# -*- coding: utf-8 -*-

RED = '\033[31m'
WHITE = '\033[37m'
RESET = '\033[0;0m'

def main():
    print("shellcode hex encode decoder")
    print("programmer : gunslinger_ <yudha.gunslinger[at]gmail.com>")
    print("what do you want to do ? {0}encode{1} / {2}decode{3}".format(RED, RESET, WHITE, RESET))
    q = input("=> ")

    if q == "encode":
        inputtype = input("Please input data : ")
        print ("shellcode => ")
        for encoded in inputtype:
            print ("\\x{0}".format(binascii.hexlify(bytes(encoded, 'utf-8')).decode()))
            sys.stdout.flush()
            time.sleep(0.5)
            print (RESET)

    elif q == "decode":
        inputtype = input("Please input data : ")
        cleaninput = inputtype.replace("\\x","")
        print ("hex       => {0}".format(inputtype))
        print ("plaintext => {0}".format(binascii.unhexlify(cleaninput).decode('utf-8')))
    else:
        print ("wrong answer ! your choice is %sencode%s or %sdecode%s" % (RED, RESET, WHITE, RESET))
        sys.exit(1)

if __name__ == '__main__':
    main()

One more version clean and with some modifications:

# -*- coding: utf-8 -*-
import sys, binascii

cor = {'vermelho': '\033[1;31m', 'branco': '\033[1;34m', 'sem_cor': '\033[0;0m'}

def shellcode(opcao, texto):
    resultado = ""
    if opcao == 'e':
        resultado += ''.join("\\x{0}".format(binascii.hexlify(bytes(s, 'utf-8')).decode()) for s in texto)
    elif opcao == 'd':
        texto = texto.replace('\\x', '')
        resultado = binascii.unhexlify(texto).decode()
    return resultado

def main():
    opcoes = "{0}encode{1} / {2}decode{3} ou sair".format(cor['vermelho'], cor['sem_cor'], cor['branco'], cor['sem_cor'])
    print("O que quer fazer? {0}".format(opcoes))
    while True:
        try:
            questao = input("Opcao: ").lower()
            dados = input("Dados: ")
            codigo = ""

            if questao in ['encode', 'enc', 'e']:
                codigo = shellcode('e', dados)
            elif questao in ['decode', 'dec', 'd']:
                codigo = shellcode('d', dados)
            elif questao in ['sair', 's']:
                sys.exit()
            else:
                sys.exit("Opcao inválida! Opcoes: {0}".format(opcoes))

            print("{0}: {1}".format(questao, codigo))
        except KeyboardInterrupt:
            sys.exit()

if __name__ == '__main__':
    main()