File CVE-2024-38875.patch of Package python-Django.34947
From 79f368764295df109a37192f6182fb6f361d85b5 Mon Sep 17 00:00:00 2001
From: Adam Johnson <me@adamj.eu>
Date: Mon, 24 Jun 2024 15:30:59 +0200
Subject: [PATCH] [4.2.x] Fixed CVE-2024-38875 -- Mitigated potential DoS in
urlize and urlizetrunc template filters.
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Thank you to Elias Myllymäki for the report.
Co-authored-by: Sarah Boyce <42296566+sarahboyce@users.noreply.github.com>
---
django/utils/html.py | 90 +++++++++++++++++++++++++---------
tests/utils_tests/test_html.py | 7 +++
2 files changed, 73 insertions(+), 24 deletions(-)
diff --git a/django/utils/html.py b/django/utils/html.py
index fdb88d6709..fd313ff9ca 100644
--- a/django/utils/html.py
+++ b/django/utils/html.py
@@ -7,7 +7,7 @@ from html.parser import HTMLParser
from urllib.parse import parse_qsl, quote, unquote, urlencode, urlsplit, urlunsplit
from django.utils.encoding import punycode
-from django.utils.functional import Promise, keep_lazy, keep_lazy_text
+from django.utils.functional import Promise, cached_property, keep_lazy, keep_lazy_text
from django.utils.http import RFC3986_GENDELIMS, RFC3986_SUBDELIMS
from django.utils.regex_helper import _lazy_re_compile
from django.utils.safestring import SafeData, SafeString, mark_safe
@@ -225,6 +225,16 @@ def smart_urlquote(url):
return urlunsplit((scheme, netloc, path, query, fragment))
+class CountsDict(dict):
+ def __init__(self, *args, word, **kwargs):
+ super().__init__(*args, *kwargs)
+ self.word = word
+
+ def __missing__(self, key):
+ self[key] = self.word.count(key)
+ return self[key]
+
+
class Urlizer:
"""
Convert any URLs in text into clickable links.
@@ -330,40 +340,72 @@ class Urlizer:
return x
return "%s…" % x[: max(0, limit - 1)]
+ @cached_property
+ def wrapping_punctuation_openings(self):
+ return "".join(dict(self.wrapping_punctuation).keys())
+
+ @cached_property
+ def trailing_punctuation_chars_no_semicolon(self):
+ return self.trailing_punctuation_chars.replace(";", "")
+
+ @cached_property
+ def trailing_punctuation_chars_has_semicolon(self):
+ return ";" in self.trailing_punctuation_chars
+
def trim_punctuation(self, word):
"""
Trim trailing and wrapping punctuation from `word`. Return the items of
the new state.
"""
- lead, middle, trail = "", word, ""
+ # Strip all opening wrapping punctuation.
+ middle = word.lstrip(self.wrapping_punctuation_openings)
+ lead = word[: len(word) - len(middle)]
+ trail = ""
+
# Continue trimming until middle remains unchanged.
trimmed_something = True
- while trimmed_something:
+ counts = CountsDict(word=middle)
+ while trimmed_something and middle:
trimmed_something = False
# Trim wrapping punctuation.
for opening, closing in self.wrapping_punctuation:
- if middle.startswith(opening):
- middle = middle[len(opening) :]
- lead += opening
- trimmed_something = True
- # Keep parentheses at the end only if they're balanced.
- if (
- middle.endswith(closing)
- and middle.count(closing) == middle.count(opening) + 1
- ):
- middle = middle[: -len(closing)]
- trail = closing + trail
- trimmed_something = True
- # Trim trailing punctuation (after trimming wrapping punctuation,
- # as encoded entities contain ';'). Unescape entities to avoid
- # breaking them by removing ';'.
- middle_unescaped = html.unescape(middle)
- stripped = middle_unescaped.rstrip(self.trailing_punctuation_chars)
- if middle_unescaped != stripped:
- punctuation_count = len(middle_unescaped) - len(stripped)
- trail = middle[-punctuation_count:] + trail
- middle = middle[:-punctuation_count]
+ if counts[opening] < counts[closing]:
+ rstripped = middle.rstrip(closing)
+ if rstripped != middle:
+ strip = counts[closing] - counts[opening]
+ trail = middle[-strip:]
+ middle = middle[:-strip]
+ trimmed_something = True
+ counts[closing] -= strip
+
+ rstripped = middle.rstrip(self.trailing_punctuation_chars_no_semicolon)
+ if rstripped != middle:
+ trail = middle[len(rstripped) :] + trail
+ middle = rstripped
trimmed_something = True
+
+ if self.trailing_punctuation_chars_has_semicolon and middle.endswith(";"):
+ # Only strip if not part of an HTML entity.
+ amp = middle.rfind("&")
+ if amp == -1:
+ can_strip = True
+ else:
+ potential_entity = middle[amp:]
+ escaped = html.unescape(potential_entity)
+ can_strip = (escaped == potential_entity) or escaped.endswith(";")
+
+ if can_strip:
+ rstripped = middle.rstrip(";")
+ amount_stripped = len(middle) - len(rstripped)
+ if amp > -1 and amount_stripped > 1:
+ # Leave a trailing semicolon as might be an entity.
+ trail = middle[len(rstripped) + 1 :] + trail
+ middle = rstripped + ";"
+ else:
+ trail = middle[len(rstripped) :] + trail
+ middle = rstripped
+ trimmed_something = True
+
return lead, middle, trail
@staticmethod
diff --git a/tests/utils_tests/test_html.py b/tests/utils_tests/test_html.py
index b7a7396075..6dab41634a 100644
--- a/tests/utils_tests/test_html.py
+++ b/tests/utils_tests/test_html.py
@@ -342,6 +342,13 @@ class TestUtilsHtml(SimpleTestCase):
"foo@.example.com",
"foo@localhost",
"foo@localhost.",
+ # trim_punctuation catastrophic tests
+ "(" * 100_000 + ":" + ")" * 100_000,
+ "(" * 100_000 + "&:" + ")" * 100_000,
+ "([" * 100_000 + ":" + "])" * 100_000,
+ "[(" * 100_000 + ":" + ")]" * 100_000,
+ "([[" * 100_000 + ":" + "]])" * 100_000,
+ "&:" + ";" * 100_000,
)
for value in tests:
with self.subTest(value=value):
--
2.45.2
