view roundup/cgi/TAL/XMLParser.py @ 5726:e199d0ae4a25

issue2551033: prevent reverse engineering hidden data by using etags as an oracle to identify when the right data has been guessed. Identified by Joseph Myers who also suggested remediation methods. Implemented John Rouillard.
author John Rouillard <rouilj@ieee.org>
date Thu, 23 May 2019 18:56:57 -0400
parents 14a61eabcea8
children
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##############################################################################
#
# Copyright (c) 2001, 2002 Zope Corporation and Contributors.
# All Rights Reserved.
#
# This software is subject to the provisions of the Zope Public License,
# Version 2.0 (ZPL).  A copy of the ZPL should accompany this distribution.
# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
# FOR A PARTICULAR PURPOSE
#
##############################################################################
# Modifications for Roundup:
# 1. commented out zLOG references
# 2. use roundup.anypy.urllib_
"""
Generic expat-based XML parser base class.
"""

#import zLOG

class XMLParser:

    ordered_attributes = 0

    handler_names = [
        "StartElementHandler",
        "EndElementHandler",
        "ProcessingInstructionHandler",
        "CharacterDataHandler",
        "UnparsedEntityDeclHandler",
        "NotationDeclHandler",
        "StartNamespaceDeclHandler",
        "EndNamespaceDeclHandler",
        "CommentHandler",
        "StartCdataSectionHandler",
        "EndCdataSectionHandler",
        "DefaultHandler",
        "DefaultHandlerExpand",
        "NotStandaloneHandler",
        "ExternalEntityRefHandler",
        "XmlDeclHandler",
        "StartDoctypeDeclHandler",
        "EndDoctypeDeclHandler",
        "ElementDeclHandler",
        "AttlistDeclHandler"
        ]

    def __init__(self, encoding=None):
        self.parser = p = self.createParser()
        # Make sure we don't get fed unicode strings in Python 2 as we
        # can't handle those
        if hasattr(self.parser, 'returns_unicode'):
            self.parser.returns_unicode = False
        if self.ordered_attributes:
            try:
                self.parser.ordered_attributes = self.ordered_attributes
            except AttributeError:
                #zLOG.LOG("TAL.XMLParser", zLOG.INFO, 
                #         "Can't set ordered_attributes")
                self.ordered_attributes = 0
        for name in self.handler_names:
            method = getattr(self, name, None)
            if method is not None:
                try:
                    setattr(p, name, method)
                except AttributeError:
                    #zLOG.LOG("TAL.XMLParser", zLOG.PROBLEM,
                    #         "Can't set expat handler %s" % name)
                    pass

    def createParser(self, encoding=None):
        global XMLParseError
        try:
            from Products.ParsedXML.Expat import pyexpat
            XMLParseError = pyexpat.ExpatError
            return pyexpat.ParserCreate(encoding, ' ')
        except ImportError:
            from xml.parsers import expat
            XMLParseError = expat.ExpatError
            return expat.ParserCreate(encoding, ' ')

    def parseFile(self, filename):
        self.parseStream(open(filename))

    def parseString(self, s):
        self.parser.Parse(s, 1)

    def parseURL(self, url):
        import roundup.anypy.urllib_
        self.parseStream(roundup.anypy.urllib_.urlopen(url))

    def parseStream(self, stream):
        self.parser.ParseFile(stream)

    def parseFragment(self, s, end=0):
        self.parser.Parse(s, end)

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