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Merge pull request #118403 from dotlambda/CVE-2021-23336

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python27: fix CVE-2021-23336
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Anderson Torres 2021-04-12 18:44:52 -03:00 committed by GitHub
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pkgs/development/interpreters/python/cpython/2.7/CVE-2021-23336.patch Normal file
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@ -0,0 +1,390 @@
From e7b005c05dbdbce967a409abd71641281a8604bf Mon Sep 17 00:00:00 2001
From: Senthil Kumaran <senthil@uthcode.com>
Date: Mon, 15 Feb 2021 11:16:43 -0800
Subject: [PATCH 24/26] [3.6] bpo-42967: only use '&' as a query string
separator (GH-24297) (GH-24532)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
bpo-42967: [security] Address a web cache-poisoning issue reported in
urllib.parse.parse_qsl().
urllib.parse will only us "&" as query string separator by default
instead of both ";" and "&" as allowed in earlier versions. An optional
argument seperator with default value "&" is added to specify the
separator.
Co-authored-by: Éric Araujo <merwok@netwok.org>
Co-authored-by: Ken Jin <28750310+Fidget-Spinner@users.noreply.github.com>
Co-authored-by: Adam Goldschmidt <adamgold7@gmail.com>
Rebased for Python 2.7 by Michał Górny
---
Doc/library/cgi.rst | 7 +++-
Doc/library/urlparse.rst | 23 ++++++++++-
Lib/cgi.py | 20 +++++++---
Lib/test/test_cgi.py | 29 +++++++++++---
Lib/test/test_urlparse.py | 38 +++++++++----------
Lib/urlparse.py | 22 ++++++++---
.../2021-02-14-15-59-16.bpo-42967.YApqDS.rst | 1 +
7 files changed, 100 insertions(+), 40 deletions(-)
create mode 100644 Misc/NEWS.d/next/Security/2021-02-14-15-59-16.bpo-42967.YApqDS.rst
diff --git a/Doc/library/cgi.rst b/Doc/library/cgi.rst
index ecd62c8c01..b85cdd8b61 100644
--- a/Doc/library/cgi.rst
+++ b/Doc/library/cgi.rst
@@ -285,10 +285,10 @@ These are useful if you want more control, or if you want to employ some of the
algorithms implemented in this module in other circumstances.
-.. function:: parse(fp[, environ[, keep_blank_values[, strict_parsing]]])
+.. function:: parse(fp[, environ[, keep_blank_values[, strict_parsing]]], separator="&")
Parse a query in the environment or from a file (the file defaults to
- ``sys.stdin`` and environment defaults to ``os.environ``). The *keep_blank_values* and *strict_parsing* parameters are
+ ``sys.stdin`` and environment defaults to ``os.environ``). The *keep_blank_values*, *strict_parsing* and *separator* parameters are
passed to :func:`urlparse.parse_qs` unchanged.
@@ -316,6 +316,9 @@ algorithms implemented in this module in other circumstances.
Note that this does not parse nested multipart parts --- use
:class:`FieldStorage` for that.
+ .. versionchanged:: 3.6.13
+ Added the *separator* parameter.
+
.. function:: parse_header(string)
diff --git a/Doc/library/urlparse.rst b/Doc/library/urlparse.rst
index 0989c88c30..2f8e4c5a44 100644
--- a/Doc/library/urlparse.rst
+++ b/Doc/library/urlparse.rst
@@ -136,7 +136,7 @@ The :mod:`urlparse` module defines the following functions:
now raise :exc:`ValueError`.
-.. function:: parse_qs(qs[, keep_blank_values[, strict_parsing[, max_num_fields]]])
+.. function:: parse_qs(qs[, keep_blank_values[, strict_parsing[, max_num_fields]]], separator='&')
Parse a query string given as a string argument (data of type
:mimetype:`application/x-www-form-urlencoded`). Data are returned as a
@@ -157,6 +157,9 @@ The :mod:`urlparse` module defines the following functions:
read. If set, then throws a :exc:`ValueError` if there are more than
*max_num_fields* fields read.
+ The optional argument *separator* is the symbol to use for separating the
+ query arguments. It defaults to ``&``.
+
Use the :func:`urllib.urlencode` function to convert such dictionaries into
query strings.
@@ -166,7 +169,14 @@ The :mod:`urlparse` module defines the following functions:
.. versionchanged:: 2.7.16
Added *max_num_fields* parameter.
-.. function:: parse_qsl(qs[, keep_blank_values[, strict_parsing[, max_num_fields]]])
+ .. versionchanged:: 2.7.18-gentoo
+ Added *separator* parameter with the default value of ``&``. Earlier
+ Python versions allowed using both ``;`` and ``&`` as query parameter
+ separator. This has been changed to allow only a single separator key,
+ with ``&`` as the default separator.
+
+
+.. function:: parse_qsl(qs[, keep_blank_values[, strict_parsing[, max_num_fields]]], separator='&')
Parse a query string given as a string argument (data of type
:mimetype:`application/x-www-form-urlencoded`). Data are returned as a list of
@@ -186,6 +196,9 @@ The :mod:`urlparse` module defines the following functions:
read. If set, then throws a :exc:`ValueError` if there are more than
*max_num_fields* fields read.
+ The optional argument *separator* is the symbol to use for separating the
+ query arguments. It defaults to ``&``.
+
Use the :func:`urllib.urlencode` function to convert such lists of pairs into
query strings.
@@ -195,6 +208,12 @@ The :mod:`urlparse` module defines the following functions:
.. versionchanged:: 2.7.16
Added *max_num_fields* parameter.
+ .. versionchanged:: 2.7.18-gentoo
+ Added *separator* parameter with the default value of ``&``. Earlier
+ Python versions allowed using both ``;`` and ``&`` as query parameter
+ separator. This has been changed to allow only a single separator key,
+ with ``&`` as the default separator.
+
.. function:: urlunparse(parts)
Construct a URL from a tuple as returned by ``urlparse()``. The *parts* argument
diff --git a/Lib/cgi.py b/Lib/cgi.py
index 5b903e0347..9d0848b6b1 100755
--- a/Lib/cgi.py
+++ b/Lib/cgi.py
@@ -121,7 +121,8 @@ log = initlog # The current logging function
# 0 ==> unlimited input
maxlen = 0
-def parse(fp=None, environ=os.environ, keep_blank_values=0, strict_parsing=0):
+def parse(fp=None, environ=os.environ, keep_blank_values=0,
+ strict_parsing=0, separator='&'):
"""Parse a query in the environment or from a file (default stdin)
Arguments, all optional:
@@ -140,6 +141,9 @@ def parse(fp=None, environ=os.environ, keep_blank_values=0, strict_parsing=0):
strict_parsing: flag indicating what to do with parsing errors.
If false (the default), errors are silently ignored.
If true, errors raise a ValueError exception.
+
+ separator: str. The symbol to use for separating the query arguments.
+ Defaults to &.
"""
if fp is None:
fp = sys.stdin
@@ -171,7 +175,8 @@ def parse(fp=None, environ=os.environ, keep_blank_values=0, strict_parsing=0):
else:
qs = ""
environ['QUERY_STRING'] = qs # XXX Shouldn't, really
- return urlparse.parse_qs(qs, keep_blank_values, strict_parsing)
+ return urlparse.parse_qs(qs, keep_blank_values, strict_parsing,
+ separator=separator)
# parse query string function called from urlparse,
@@ -395,7 +400,7 @@ class FieldStorage:
def __init__(self, fp=None, headers=None, outerboundary="",
environ=os.environ, keep_blank_values=0, strict_parsing=0,
- max_num_fields=None):
+ max_num_fields=None, separator='&'):
"""Constructor. Read multipart/* until last part.
Arguments, all optional:
@@ -430,6 +435,7 @@ class FieldStorage:
self.keep_blank_values = keep_blank_values
self.strict_parsing = strict_parsing
self.max_num_fields = max_num_fields
+ self.separator = separator
if 'REQUEST_METHOD' in environ:
method = environ['REQUEST_METHOD'].upper()
self.qs_on_post = None
@@ -613,7 +619,8 @@ class FieldStorage:
if self.qs_on_post:
qs += '&' + self.qs_on_post
query = urlparse.parse_qsl(qs, self.keep_blank_values,
- self.strict_parsing, self.max_num_fields)
+ self.strict_parsing, self.max_num_fields,
+ separator=self.separator)
self.list = [MiniFieldStorage(key, value) for key, value in query]
self.skip_lines()
@@ -629,7 +636,8 @@ class FieldStorage:
query = urlparse.parse_qsl(self.qs_on_post,
self.keep_blank_values,
self.strict_parsing,
- self.max_num_fields)
+ self.max_num_fields,
+ separator=self.separator)
self.list.extend(MiniFieldStorage(key, value)
for key, value in query)
FieldStorageClass = None
@@ -649,7 +657,7 @@ class FieldStorage:
headers = rfc822.Message(self.fp)
part = klass(self.fp, headers, ib,
environ, keep_blank_values, strict_parsing,
- max_num_fields)
+ max_num_fields, separator=self.separator)
if max_num_fields is not None:
max_num_fields -= 1
diff --git a/Lib/test/test_cgi.py b/Lib/test/test_cgi.py
index 743c2afbd4..f414faa23b 100644
--- a/Lib/test/test_cgi.py
+++ b/Lib/test/test_cgi.py
@@ -61,12 +61,9 @@ parse_strict_test_cases = [
("", ValueError("bad query field: ''")),
("&", ValueError("bad query field: ''")),
("&&", ValueError("bad query field: ''")),
- (";", ValueError("bad query field: ''")),
- (";&;", ValueError("bad query field: ''")),
# Should the next few really be valid?
("=", {}),
("=&=", {}),
- ("=;=", {}),
# This rest seem to make sense
("=a", {'': ['a']}),
("&=a", ValueError("bad query field: ''")),
@@ -81,8 +78,6 @@ parse_strict_test_cases = [
("a=a+b&b=b+c", {'a': ['a b'], 'b': ['b c']}),
("a=a+b&a=b+a", {'a': ['a b', 'b a']}),
("x=1&y=2.0&z=2-3.%2b0", {'x': ['1'], 'y': ['2.0'], 'z': ['2-3.+0']}),
- ("x=1;y=2.0&z=2-3.%2b0", {'x': ['1'], 'y': ['2.0'], 'z': ['2-3.+0']}),
- ("x=1;y=2.0;z=2-3.%2b0", {'x': ['1'], 'y': ['2.0'], 'z': ['2-3.+0']}),
("Hbc5161168c542333633315dee1182227:key_store_seqid=400006&cuyer=r&view=bustomer&order_id=0bb2e248638833d48cb7fed300000f1b&expire=964546263&lobale=en-US&kid=130003.300038&ss=env",
{'Hbc5161168c542333633315dee1182227:key_store_seqid': ['400006'],
'cuyer': ['r'],
@@ -188,6 +183,30 @@ class CgiTests(unittest.TestCase):
self.assertEqual(expect[k], v)
self.assertItemsEqual(expect.values(), d.values())
+ def test_separator(self):
+ parse_semicolon = [
+ ("x=1;y=2.0", {'x': ['1'], 'y': ['2.0']}),
+ ("x=1;y=2.0;z=2-3.%2b0", {'x': ['1'], 'y': ['2.0'], 'z': ['2-3.+0']}),
+ (";", ValueError("bad query field: ''")),
+ (";;", ValueError("bad query field: ''")),
+ ("=;a", ValueError("bad query field: 'a'")),
+ (";b=a", ValueError("bad query field: ''")),
+ ("b;=a", ValueError("bad query field: 'b'")),
+ ("a=a+b;b=b+c", {'a': ['a b'], 'b': ['b c']}),
+ ("a=a+b;a=b+a", {'a': ['a b', 'b a']}),
+ ]
+ for orig, expect in parse_semicolon:
+ env = {'QUERY_STRING': orig}
+ fs = cgi.FieldStorage(separator=';', environ=env)
+ if isinstance(expect, dict):
+ for key in expect.keys():
+ expect_val = expect[key]
+ self.assertIn(key, fs)
+ if len(expect_val) > 1:
+ self.assertEqual(fs.getvalue(key), expect_val)
+ else:
+ self.assertEqual(fs.getvalue(key), expect_val[0])
+
def test_log(self):
cgi.log("Testing")
diff --git a/Lib/test/test_urlparse.py b/Lib/test/test_urlparse.py
index 86c4a0595c..0b2107339a 100644
--- a/Lib/test/test_urlparse.py
+++ b/Lib/test/test_urlparse.py
@@ -24,16 +24,20 @@ parse_qsl_test_cases = [
("&a=b", [('a', 'b')]),
("a=a+b&b=b+c", [('a', 'a b'), ('b', 'b c')]),
("a=1&a=2", [('a', '1'), ('a', '2')]),
- (";", []),
- (";;", []),
- (";a=b", [('a', 'b')]),
- ("a=a+b;b=b+c", [('a', 'a b'), ('b', 'b c')]),
- ("a=1;a=2", [('a', '1'), ('a', '2')]),
- (b";", []),
- (b";;", []),
- (b";a=b", [(b'a', b'b')]),
- (b"a=a+b;b=b+c", [(b'a', b'a b'), (b'b', b'b c')]),
- (b"a=1;a=2", [(b'a', b'1'), (b'a', b'2')]),
+ (b"", []),
+ (b"&", []),
+ (b"&&", []),
+ (b"=", [(b'', b'')]),
+ (b"=a", [(b'', b'a')]),
+ (b"a", [(b'a', b'')]),
+ (b"a=", [(b'a', b'')]),
+ (b"&a=b", [(b'a', b'b')]),
+ (b"a=a+b&b=b+c", [(b'a', b'a b'), (b'b', b'b c')]),
+ (b"a=1&a=2", [(b'a', b'1'), (b'a', b'2')]),
+ (";a=b", [(';a', 'b')]),
+ ("a=a+b;b=b+c", [('a', 'a b;b=b c')]),
+ (b";a=b", [(b';a', b'b')]),
+ (b"a=a+b;b=b+c", [(b'a', b'a b;b=b c')]),
]
parse_qs_test_cases = [
@@ -57,16 +61,10 @@ parse_qs_test_cases = [
(b"&a=b", {b'a': [b'b']}),
(b"a=a+b&b=b+c", {b'a': [b'a b'], b'b': [b'b c']}),
(b"a=1&a=2", {b'a': [b'1', b'2']}),
- (";", {}),
- (";;", {}),
- (";a=b", {'a': ['b']}),
- ("a=a+b;b=b+c", {'a': ['a b'], 'b': ['b c']}),
- ("a=1;a=2", {'a': ['1', '2']}),
- (b";", {}),
- (b";;", {}),
- (b";a=b", {b'a': [b'b']}),
- (b"a=a+b;b=b+c", {b'a': [b'a b'], b'b': [b'b c']}),
- (b"a=1;a=2", {b'a': [b'1', b'2']}),
+ (";a=b", {';a': ['b']}),
+ ("a=a+b;b=b+c", {'a': ['a b;b=b c']}),
+ (b";a=b", {b';a': [b'b']}),
+ (b"a=a+b;b=b+c", {b'a':[ b'a b;b=b c']}),
]
class UrlParseTestCase(unittest.TestCase):
diff --git a/Lib/urlparse.py b/Lib/urlparse.py
index 798b467b60..6c32727fce 100644
--- a/Lib/urlparse.py
+++ b/Lib/urlparse.py
@@ -382,7 +382,8 @@ def unquote(s):
append(item)
return ''.join(res)
-def parse_qs(qs, keep_blank_values=0, strict_parsing=0, max_num_fields=None):
+def parse_qs(qs, keep_blank_values=0, strict_parsing=0, max_num_fields=None,
+ separator='&'):
"""Parse a query given as a string argument.
Arguments:
@@ -402,17 +403,22 @@ def parse_qs(qs, keep_blank_values=0, strict_parsing=0, max_num_fields=None):
max_num_fields: int. If set, then throws a ValueError if there
are more than n fields read by parse_qsl().
+
+ separator: str. The symbol to use for separating the query arguments.
+ Defaults to &.
+
"""
dict = {}
for name, value in parse_qsl(qs, keep_blank_values, strict_parsing,
- max_num_fields):
+ max_num_fields, separator=separator):
if name in dict:
dict[name].append(value)
else:
dict[name] = [value]
return dict
-def parse_qsl(qs, keep_blank_values=0, strict_parsing=0, max_num_fields=None):
+def parse_qsl(qs, keep_blank_values=0, strict_parsing=0, max_num_fields=None,
+ separator='&'):
"""Parse a query given as a string argument.
Arguments:
@@ -432,17 +438,23 @@ def parse_qsl(qs, keep_blank_values=0, strict_parsing=0, max_num_fields=None):
max_num_fields: int. If set, then throws a ValueError if there
are more than n fields read by parse_qsl().
+ separator: str. The symbol to use for separating the query arguments.
+ Defaults to &.
+
Returns a list, as G-d intended.
"""
+ if not separator or (not isinstance(separator, (str, bytes))):
+ raise ValueError("Separator must be of type string or bytes.")
+
# If max_num_fields is defined then check that the number of fields
# is less than max_num_fields. This prevents a memory exhaustion DOS
# attack via post bodies with many fields.
if max_num_fields is not None:
- num_fields = 1 + qs.count('&') + qs.count(';')
+ num_fields = 1 + qs.count(separator)
if max_num_fields < num_fields:
raise ValueError('Max number of fields exceeded')
- pairs = [s2 for s1 in qs.split('&') for s2 in s1.split(';')]
+ pairs = [s1 for s1 in qs.split(separator)]
r = []
for name_value in pairs:
if not name_value and not strict_parsing:
diff --git a/Misc/NEWS.d/next/Security/2021-02-14-15-59-16.bpo-42967.YApqDS.rst b/Misc/NEWS.d/next/Security/2021-02-14-15-59-16.bpo-42967.YApqDS.rst
new file mode 100644
index 0000000000..f08489b414
--- /dev/null
+++ b/Misc/NEWS.d/next/Security/2021-02-14-15-59-16.bpo-42967.YApqDS.rst
@@ -0,0 +1 @@
+Fix web cache poisoning vulnerability by defaulting the query args separator to ``&``, and allowing the user to choose a custom separator.
--
2.31.1

2
pkgs/development/interpreters/python/cpython/2.7/default.nix
View file

@ -123,6 +123,8 @@ let
./CVE-2021-3177.patch
./CVE-2021-23336.patch
# The workaround is for unittests on Win64, which we don't support.
# It does break aarch64-darwin, which we do support. See:
# * https://bugs.python.org/issue35523