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# Copyright 2013 IBM Corp.
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
from xml.dom import minidom
from xml.parsers import expat
from xml import sax
from xml.sax import expatreader
from trove.common.i18n import _
class ProtectedExpatParser(expatreader.ExpatParser):
"""An expat parser which disables DTD's and entities by default."""
def __init__(self, forbid_dtd=True, forbid_entities=True,
*args, **kwargs):
# Python 2.x old style class
expatreader.ExpatParser.__init__(self, *args, **kwargs)
self.forbid_dtd = forbid_dtd
self.forbid_entities = forbid_entities
def start_doctype_decl(self, name, sysid, pubid, has_internal_subset):
raise ValueError(_("Inline DTD forbidden"))
def entity_decl(self, entityName, is_parameter_entity, value, base,
systemId, publicId, notationName):
raise ValueError(_("<!ENTITY> entity declaration forbidden"))
def unparsed_entity_decl(self, name, base, sysid, pubid, notation_name):
# expat 1.2
raise ValueError(_("<!ENTITY> unparsed entity forbidden"))
def external_entity_ref(self, context, base, systemId, publicId):
raise ValueError(_("<!ENTITY> external entity forbidden"))
def notation_decl(self, name, base, sysid, pubid):
raise ValueError(_("<!ENTITY> notation forbidden"))
def reset(self):
expatreader.ExpatParser.reset(self)
if self.forbid_dtd:
self._parser.StartDoctypeDeclHandler = self.start_doctype_decl
self._parser.EndDoctypeDeclHandler = None
if self.forbid_entities:
self._parser.EntityDeclHandler = self.entity_decl
self._parser.UnparsedEntityDeclHandler = self.unparsed_entity_decl
self._parser.ExternalEntityRefHandler = self.external_entity_ref
self._parser.NotationDeclHandler = self.notation_decl
try:
self._parser.SkippedEntityHandler = None
except AttributeError:
# some pyexpat versions do not support SkippedEntity
pass
def safe_minidom_parse_string(xml_string):
"""Parse an XML string using minidom safely.
"""
try:
return minidom.parseString(xml_string, parser=ProtectedExpatParser())
except sax.SAXParseException:
raise expat.ExpatError()
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