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From: "Miss Islington (bot)"
<31488909+miss-islington@users.noreply.github.com>
Date: Wed, 4 Sep 2024 17:49:40 +0200
Subject: gh-123067: Fix quadratic complexity in parsing "-quoted cookie
values with backslashes (GH-123075) (#123107)
This fixes CVE-2024-7592.
(cherry picked from commit 44e458357fca05ca0ae2658d62c8c595b048b5ef)
Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>
Origin: cpython, https://github.com/python/cpython/commit/d662e2db2605515a767f88ad48096b8ac623c774
---
lib-python/3/http/cookies.py | 34 +++++++-----------------------
lib-python/3/test/test_http_cookies.py | 38 ++++++++++++++++++++++++++++++++++
2 files changed, 46 insertions(+), 26 deletions(-)
diff --git a/lib-python/3/http/cookies.py b/lib-python/3/http/cookies.py
index 35ac2dc..2c1f021 100644
--- a/lib-python/3/http/cookies.py
+++ b/lib-python/3/http/cookies.py
@@ -184,8 +184,13 @@ def _quote(str):
return '"' + str.translate(_Translator) + '"'
-_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[1]:
+ return chr(int(m[1], 8))
+ else:
+ return m[2]
def _unquote(str):
# If there aren't any doublequotes,
@@ -205,30 +210,7 @@ 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
diff --git a/lib-python/3/test/test_http_cookies.py b/lib-python/3/test/test_http_cookies.py
index 6072c7e..644e75c 100644
--- a/lib-python/3/test/test_http_cookies.py
+++ b/lib-python/3/test/test_http_cookies.py
@@ -5,6 +5,7 @@ from test.support import run_unittest, run_doctest
import unittest
from http import cookies
import pickle
+from test import support
class CookieTests(unittest.TestCase):
@@ -58,6 +59,43 @@ 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)
+
+ @support.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')
|
