File CVE-2021-23336-only-amp-as-query-sep.patch of Package python-base.32576
From 5c17dfc5d70ce88be99bc5769b91ce79d7a90d61 Mon Sep 17 00:00:00 2001
From: Senthil Kumaran <senthil@uthcode.com>
Date: Mon, 15 Feb 2021 11:16:43 -0800
Subject: [PATCH] [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>
---
Doc/library/cgi.rst | 8 ++-
Doc/library/urllib.parse.rst | 22 +++++-
Doc/whatsnew/3.6.rst | 13 ++++
Lib/cgi.py | 17 +++--
Lib/test/test_cgi.py | 29 ++++++--
Lib/test/test_urlparse.py | 68 +++++++++++++------
Lib/urllib/parse.py | 19 ++++--
.../2021-02-14-15-59-16.bpo-42967.YApqDS.rst | 1 +
8 files changed, 134 insertions(+), 43 deletions(-)
create mode 100644 Misc/NEWS.d/next/Security/2021-02-14-15-59-16.bpo-42967.YApqDS.rst
--- a/Doc/library/cgi.rst
+++ b/Doc/library/cgi.rst
@@ -287,10 +287,11 @@ algorithms implemented in this module in
.. function:: parse(fp[, environ[, keep_blank_values[, strict_parsing]]])
- 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
- passed to :func:`urlparse.parse_qs` unchanged.
-
+ 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*, *strict_parsing*,
+ and *separator* parameters are passed to
+ :func:`urlparse.parse_qs` unchanged.
.. function:: parse_qs(qs[, keep_blank_values[, strict_parsing[, max_num_fields]]])
@@ -316,6 +317,9 @@ algorithms implemented in this module in
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)
--- a/Lib/cgi.py
+++ b/Lib/cgi.py
@@ -121,7 +121,8 @@ log = initlog # The current lo
# 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, k
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, k
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 +619,9 @@ 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 +637,8 @@ 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,
+ self.separator)
self.list.extend(MiniFieldStorage(key, value)
for key, value in query)
FieldStorageClass = None
@@ -642,7 +651,8 @@ class FieldStorage:
klass = self.FieldStorageClass or self.__class__
part = klass(self.fp, {}, ib,
environ, keep_blank_values, strict_parsing,
- max_num_fields)
+ max_num_fields,
+ self.separator)
# Throw first part away
while not part.done:
--- 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")
--- a/Lib/test/test_urlparse.py
+++ b/Lib/test/test_urlparse.py
@@ -24,16 +24,10 @@ 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')]),
+ (";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 +51,10 @@ 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):
@@ -665,6 +653,43 @@ class UrlParseTestCase(unittest.TestCase
"under NFKC normalization")
self.assertIsInstance(cm.exception.args[0], str)
+ def test_parse_qs_separator(self):
+ parse_qs_semicolon_cases = [
+ (";", {}),
+ (";;", {}),
+ (";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']}),
+ ]
+ for orig, expect in parse_qs_semicolon_cases:
+ result = urlparse.parse_qs(orig, separator=';')
+ self.assertEqual(result, expect, "Error parsing %r" % orig)
+
+
+ def test_parse_qsl_separator(self):
+ parse_qsl_semicolon_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')]),
+ (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')]),
+ ]
+ for orig, expect in parse_qsl_semicolon_cases:
+ result = urlparse.parse_qsl(orig, separator=';')
+ self.assertEqual(result, expect, "Error parsing %r" % orig)
+
+
+
def test_main():
test_support.run_unittest(UrlParseTestCase)
--- /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.
--- a/Lib/test/test_urllib2.py
+++ b/Lib/test/test_urllib2.py
@@ -1331,7 +1331,7 @@ class MiscTests(unittest.TestCase, FakeH
# level 'def urlopen()' function defined in this... (quite ugly)
# test suite. They use different url opening codepaths. Plain
# urlopen uses FancyURLOpener which goes via a codepath that
- # calls urllib.parse.quote() on the URL which makes all of the
+ # calls urlparse.quote() on the URL which makes all of the
# above attempts at injection within the url _path_ safe.
escaped_char_repr = repr(char).replace('\\', r'\\')
InvalidURL = httplib.InvalidURL
@@ -1354,7 +1354,7 @@ class MiscTests(unittest.TestCase, FakeH
# level 'def urlopen()' function defined in this... (quite ugly)
# test suite. They use different url opening codepaths. Plain
# urlopen uses FancyURLOpener which goes via a codepath that
- # calls urllib.parse.quote() on the URL which makes all of the
+ # calls urlparse.quote() on the URL which makes all of the
# above attempts at injection within the url _path_ safe.
InvalidURL = httplib.InvalidURL
with self.assertRaisesRegexp(InvalidURL,
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -4246,7 +4246,7 @@ Library
- bpo-18167: cgi.FieldStorage no longer fails to handle multipart/form-data
when \r\n appears at end of 65535 bytes without other newlines.
-- bpo-17403: urllib.parse.robotparser normalizes the urls before adding to
+- bpo-17403: urlparse.robotparser normalizes the urls before adding to
ruleline. This helps in handling certain types invalid urls in a
conservative manner. Patch contributed by Mher Movsisyan.
@@ -8271,7 +8271,7 @@ Core and Builtins
Library
-------
-- bpo-7904: Changes to urllib.parse.urlsplit to handle schemes as defined by
+- bpo-7904: Changes to urlparse.urlsplit to handle schemes as defined by
RFC3986. Anything before :// is considered a scheme and is followed by an
authority (or netloc) and by '/' led path, which is optional.
--- 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 +403,21 @@ def parse_qs(qs, keep_blank_values=0, st
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 +437,23 @@ def parse_qsl(qs, keep_blank_values=0, s
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 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 not separator or (not isinstance(separator, (str, bytes))):
+ raise ValueError("Separator must be of type string or bytes.")
+
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:
