File CVE-2024-7592-quad-complex-cookies.patch of Package python3.38021
From cdffb9f1bec386198a9fc7483a8f1ad343f48ce2 Mon Sep 17 00:00:00 2001
From: Serhiy Storchaka <storchaka@gmail.com>
Date: Sat, 17 Aug 2024 16:30:52 +0300
Subject: [PATCH] [CVE-2024-7592] Fix quadratic complexity in parsing "-quoted
cookie
Fix quadratic complexity in parsing ``"``-quoted cookie values
with backslashes by `http.cookies`.
Fixes: gh#python/cpython#123067
Fixes: bsc#1229596 (CVE-2024-7592)
From-PR: gh#python/cpython!123075
Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>
Patch: CVE-2024-7592-quad-complex-cookies.patch
---
Lib/http/cookies.py | 34 ++------
Lib/test/test_http_cookies.py | 39 +++++++++-
Misc/NEWS.d/next/Library/2024-08-16-19-13-21.gh-issue-123067.Nx9O4R.rst | 1
3 files changed, 47 insertions(+), 27 deletions(-)
create mode 100644 Misc/NEWS.d/next/Library/2024-08-16-19-13-21.gh-issue-123067.Nx9O4R.rst
--- a/Lib/http/cookies.py
+++ b/Lib/http/cookies.py
@@ -235,8 +235,13 @@ def _quote(str, LegalChars=_LegalChars):
return '"' + _nulljoin(_Translator.get(s, s) for s in str) + '"'
-_OctalPatt = re.compile(r"\\[0-3][0-7][0-7]")
-_QuotePatt = re.compile(r"[\\].")
+_unquote_sub = re.compile(r'\\(?:([0-3][0-7][0-7])|(.))').sub
+
+def _unquote_replace(m):
+ if m.group(1):
+ return chr(int(m.group(1), 8))
+ else:
+ return m.group(2)
def _unquote(str):
# If there aren't any doublequotes,
@@ -256,30 +261,7 @@ def _unquote(str):
# \012 --> \n
# \" --> "
#
- i = 0
- n = len(str)
- res = []
- while 0 <= i < n:
- o_match = _OctalPatt.search(str, i)
- q_match = _QuotePatt.search(str, i)
- if not o_match and not q_match: # Neither matched
- res.append(str[i:])
- break
- # else:
- j = k = -1
- if o_match:
- j = o_match.start(0)
- if q_match:
- k = q_match.start(0)
- if q_match and (not o_match or k < j): # QuotePatt matched
- res.append(str[i:k])
- res.append(str[k+1])
- i = k + 2
- else: # OctalPatt matched
- res.append(str[i:j])
- res.append(chr(int(str[j+1:j+4], 8)))
- i = j + 4
- return _nulljoin(res)
+ return _unquote_sub(_unquote_replace, str)
# The _getdate() routine is used to set the expiration time in the cookie's HTTP
# header. By default, _getdate() returns the current time in the appropriate
--- a/Lib/test/test_http_cookies.py
+++ b/Lib/test/test_http_cookies.py
@@ -1,6 +1,6 @@
# Simple test suite for http/cookies.py
-from test.support import run_unittest, run_doctest, check_warnings
+from test.support import run_unittest, run_doctest, check_warnings, requires_resource
import unittest
from http import cookies
import pickle
@@ -66,6 +66,43 @@ class CookieTests(unittest.TestCase):
for k, v in sorted(case['dict'].items()):
self.assertEqual(C[k].value, v)
+ def test_unquote(self):
+ cases = [
+ (r'a="b=\""', 'b="'),
+ (r'a="b=\\"', 'b=\\'),
+ (r'a="b=\="', 'b=='),
+ (r'a="b=\n"', 'b=n'),
+ (r'a="b=\042"', 'b="'),
+ (r'a="b=\134"', 'b=\\'),
+ (r'a="b=\377"', 'b=\xff'),
+ (r'a="b=\400"', 'b=400'),
+ (r'a="b=\42"', 'b=42'),
+ (r'a="b=\\042"', 'b=\\042'),
+ (r'a="b=\\134"', 'b=\\134'),
+ (r'a="b=\\\""', 'b=\\"'),
+ (r'a="b=\\\042"', 'b=\\"'),
+ (r'a="b=\134\""', 'b=\\"'),
+ (r'a="b=\134\042"', 'b=\\"'),
+ ]
+ for encoded, decoded in cases:
+ with self.subTest(encoded):
+ C = cookies.SimpleCookie()
+ C.load(encoded)
+ self.assertEqual(C['a'].value, decoded)
+
+ @requires_resource('cpu')
+ def test_unquote_large(self):
+ n = 10**6
+ for encoded in r'\\', r'\134':
+ with self.subTest(encoded):
+ data = 'a="b=' + encoded*n + ';"'
+ C = cookies.SimpleCookie()
+ C.load(data)
+ value = C['a'].value
+ self.assertEqual(value[:3], 'b=\\')
+ self.assertEqual(value[-2:], '\\;')
+ self.assertEqual(len(value), n + 3)
+
def test_load(self):
C = cookies.SimpleCookie()
C.load('Customer="WILE_E_COYOTE"; Version=1; Path=/acme')
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2024-08-16-19-13-21.gh-issue-123067.Nx9O4R.rst
@@ -0,0 +1 @@
+Fix quadratic complexity in parsing ``"``-quoted cookie values with backslashes by :mod:`http.cookies`.
