1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
|
# defusedxml
#
# Copyright (c) 2013 by Christian Heimes <christian@python.org>
# Licensed to PSF under a Contributor Agreement.
# See https://www.python.org/psf/license for licensing details.
"""Common constants, exceptions and helpe functions
"""
import sys
import xml.parsers.expat
PY3 = sys.version_info[0] == 3
# Python 3.9 removed cElementTree module
_HAVE_CELEMENTTREE = sys.version_info < (3, 9, 0)
# Fail early when pyexpat is not installed correctly
if not hasattr(xml.parsers.expat, "ParserCreate"):
raise ImportError("pyexpat") # pragma: no cover
class DefusedXmlException(ValueError):
"""Base exception
"""
def __repr__(self):
return str(self)
class DTDForbidden(DefusedXmlException):
"""Document type definition is forbidden
"""
def __init__(self, name, sysid, pubid):
super(DTDForbidden, self).__init__()
self.name = name
self.sysid = sysid
self.pubid = pubid
def __str__(self):
tpl = "DTDForbidden(name='{}', system_id={!r}, public_id={!r})"
return tpl.format(self.name, self.sysid, self.pubid)
class EntitiesForbidden(DefusedXmlException):
"""Entity definition is forbidden
"""
def __init__(self, name, value, base, sysid, pubid, notation_name):
super(EntitiesForbidden, self).__init__()
self.name = name
self.value = value
self.base = base
self.sysid = sysid
self.pubid = pubid
self.notation_name = notation_name
def __str__(self):
tpl = "EntitiesForbidden(name='{}', system_id={!r}, public_id={!r})"
return tpl.format(self.name, self.sysid, self.pubid)
class ExternalReferenceForbidden(DefusedXmlException):
"""Resolving an external reference is forbidden
"""
def __init__(self, context, base, sysid, pubid):
super(ExternalReferenceForbidden, self).__init__()
self.context = context
self.base = base
self.sysid = sysid
self.pubid = pubid
def __str__(self):
tpl = "ExternalReferenceForbidden(system_id='{}', public_id={})"
return tpl.format(self.sysid, self.pubid)
class NotSupportedError(DefusedXmlException):
"""The operation is not supported
"""
def _apply_defusing(defused_mod):
assert defused_mod is sys.modules[defused_mod.__name__]
stdlib_name = defused_mod.__origin__
__import__(stdlib_name, {}, {}, ["*"])
stdlib_mod = sys.modules[stdlib_name]
stdlib_names = set(dir(stdlib_mod))
for name, obj in vars(defused_mod).items():
if name.startswith("_") or name not in stdlib_names:
continue
setattr(stdlib_mod, name, obj)
return stdlib_mod
def _generate_etree_functions(DefusedXMLParser, _TreeBuilder, _parse, _iterparse):
"""Factory for functions needed by etree, dependent on whether
cElementTree or ElementTree is used."""
def parse(source, parser=None, forbid_dtd=False, forbid_entities=True, forbid_external=True):
if parser is None:
parser = DefusedXMLParser(
target=_TreeBuilder(),
forbid_dtd=forbid_dtd,
forbid_entities=forbid_entities,
forbid_external=forbid_external,
)
return _parse(source, parser)
def iterparse(
source,
events=None,
parser=None,
forbid_dtd=False,
forbid_entities=True,
forbid_external=True,
):
if parser is None:
parser = DefusedXMLParser(
target=_TreeBuilder(),
forbid_dtd=forbid_dtd,
forbid_entities=forbid_entities,
forbid_external=forbid_external,
)
return _iterparse(source, events, parser)
def fromstring(text, forbid_dtd=False, forbid_entities=True, forbid_external=True):
parser = DefusedXMLParser(
target=_TreeBuilder(),
forbid_dtd=forbid_dtd,
forbid_entities=forbid_entities,
forbid_external=forbid_external,
)
parser.feed(text)
return parser.close()
return parse, iterparse, fromstring
|
