#!/usr/bin/env python

"""
Copyright (c) 2006-2020 sqlmap developers (http://sqlmap.org/)
See the file 'LICENSE' for copying permission
"""

import os
import re

from lib.core.common import singleTimeWarnMessage
from lib.core.convert import decodeHex
from lib.core.convert import getOrds
from lib.core.enums import DBMS
from lib.core.enums import PRIORITY

__priority__ = PRIORITY.NORMAL

def dependencies():
    singleTimeWarnMessage("tamper script '%s' is only meant to be run against %s" % (os.path.basename(__file__).split(".")[0], DBMS.MYSQL))

def tamper(payload, **kwargs):
    """
    Replaces each (MySQL) 0x<hex> encoded string with equivalent CONCAT(CHAR(),...) counterpart

    Requirement:
        * MySQL

    Tested against:
        * MySQL 4, 5.0 and 5.5

    Notes:
        * Useful in cases when web application does the upper casing

    >>> tamper('SELECT 0xdeadbeef')
    'SELECT CONCAT(CHAR(222),CHAR(173),CHAR(190),CHAR(239))'
    """

    retVal = payload

    if payload:
        for match in re.finditer(r"\b0x([0-9a-f]+)\b", retVal):
            if len(match.group(1)) > 2:
                result = "CONCAT(%s)" % ','.join("CHAR(%d)" % _ for _ in getOrds(decodeHex(match.group(1))))
            else:
                result = "CHAR(%d)" % ord(decodeHex(match.group(1)))
            retVal = retVal.replace(match.group(0), result)

    return retVal
