'''
modsecurity.py

Copyright 2006 Andres Riancho

This file is part of w3af, w3af.sourceforge.net .

w3af is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation version 2 of the License.

w3af is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with w3af; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

'''

from core.controllers.basePlugin.baseEvasionPlugin import baseEvasionPlugin
from core.controllers.w3afException import w3afException

from core.data.parsers.urlParser import parse_qs
from core.data.url.HTTPRequest import HTTPRequest as HTTPRequest

# options
from core.data.options.option import option
from core.data.options.optionList import optionList

import urllib2
import copy


class modsecurity(baseEvasionPlugin):
    '''
    Evade detection using a mod_security vulnerability.
    
    @author: Francisco Amato ( famato |at| infobyte.com.ar )
    '''

    def __init__(self):
        baseEvasionPlugin.__init__(self)

    def modifyRequest(self, request ):
        '''
        Mangles the request
        
        @parameter request: HTTPRequest instance that is going to be modified by the evasion plugin
        @return: The modified request
        
        >>> from core.data.parsers.urlParser import url_object
        >>> modsec = modsecurity()
        
        >>> u = url_object('http://www.google.com/')
        >>> r = HTTPRequest( u )
        >>> modsec.modifyRequest( r ).url_object.url_string
        'http://www.google.com/'

        >>> u = url_object('http://www.google.com/')
        >>> r = HTTPRequest( u, data='' )
        >>> modsec.modifyRequest( r ).get_data()
        ''

        >>> u = url_object('http://www.google.com/')
        >>> r = HTTPRequest( u, data='a=b' )
        >>> modsec.modifyRequest( r ).get_data()
        '\\x00a=b'

        '''
        # Mangle the postdata
        data = str(request.get_data())
        if data:
            
            try:
                # Only mangle the postdata if it is a url encoded string
                parse_qs( data )
            except:
                pass
            else:
                data = '\x00' + data 
                headers_copy = copy.deepcopy(request.headers)
                headers_copy['content-length'] = str(len(data))
                
                request = HTTPRequest( request.url_object, data, headers_copy, 
                                       request.get_origin_req_host() )
                
        return request

    def getOptions( self ):
        '''
        @return: A list of option objects for this plugin.
        '''    
        ol = optionList()
        return ol

    def setOptions( self, OptionList ):
        '''
        This method sets all the options that are configured using the user interface 
        generated by the framework using the result of getOptions().
        
        @parameter OptionList: A dictionary with the options for the plugin.
        @return: No value is returned.
        ''' 
        pass
        
    def getPluginDeps( self ):
        '''
        @return: A list with the names of the plugins that should be runned before the
        current one.
        '''        
        return []

    def getPriority( self ):
        '''
        This function is called when sorting evasion plugins.
        Each evasion plugin should implement this.
        
        @return: An integer specifying the priority. 0 is runned first, 100 last.
        '''
        return 50
    
    def getLongDesc( self ):
        '''
        @return: A DETAILED description of the plugin functions and features.
        '''
        return '''
        This evasion plugin performs a bypass for mod_security version 2.1.0 or less here:
            - http://www.php-security.org/MOPB/BONUS-12-2007.html
        
        Important: The evasion only works for postdata.
        
        Example:
            Postdata Input:      'a=b'
            Postdata Output :    '\\x00a=b'
        '''
