#!/usr/bin/env python

"""
Copyright (c) 2006-2017 sqlmap developers (http://sqlmap.org/)
See the file 'LICENSE' for copying permission
"""

import re

from lib.core.data import kb
from lib.core.enums import PRIORITY

__priority__ = PRIORITY.NORMAL

def dependencies():
    pass

def tamper(payload, **kwargs):
    """
    Replaces space character after SQL statement with a valid random blank character.
    Afterwards replace character = with LIKE operator

    Requirement:
        * Blue Coat SGOS with WAF activated as documented in
        https://kb.bluecoat.com/index?page=content&id=FAQ2147

    Tested against:
        * MySQL 5.1, SGOS

    Notes:
        * Useful to bypass Blue Coat's recommended WAF rule configuration

    >>> tamper('SELECT id FROM users WHERE id = 1')
    'SELECT%09id FROM%09users WHERE%09id LIKE 1'
    """

    def process(match):
        word = match.group('word')
        if word.upper() in kb.keywords:
            return match.group().replace(word, "%s%%09" % word)
        else:
            return match.group()

    retVal = payload

    if payload:
        retVal = re.sub(r"\b(?P<word>[A-Z_]+)(?=[^\w(]|\Z)", lambda match: process(match), retVal)
        retVal = re.sub(r"\s*=\s*", " LIKE ", retVal)
        retVal = retVal.replace("%09 ", "%09")

    return retVal
