92 lines
3.4 KiB
Diff
92 lines
3.4 KiB
Diff
From 790eb058b0716c536a2f2e8d1c6d5079d776c22b Mon Sep 17 00:00:00 2001
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From: Sarah Boyce <42296566+sarahboyce@users.noreply.github.com>
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Date: Wed, 13 Nov 2024 15:06:23 +0100
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Subject: [PATCH] [4.2.x] Fixed CVE-2024-53907 -- Mitigated potential DoS in
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strip_tags().
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Origin: https://github.com/django/django/commit/790eb058b0716c536a2f2e8d1c6d5079d776c22b
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Thanks to jiangniao for the report, and Shai Berger and Natalia Bidart
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for the reviews.
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---
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django/utils/html.py | 10 ++++++++--
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tests/utils_tests/test_html.py | 7 +++++++
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2 files changed, 15 insertions(+), 2 deletions(-)
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diff --git a/django/utils/html.py b/django/utils/html.py
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index b3a6122..a8d23ce 100644
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--- a/django/utils/html.py
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+++ b/django/utils/html.py
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@@ -12,6 +12,7 @@ from django.utils.functional import Promise, keep_lazy, keep_lazy_text
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from django.utils.http import RFC3986_GENDELIMS, RFC3986_SUBDELIMS
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from django.utils.safestring import SafeData, SafeText, mark_safe
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from django.utils.text import normalize_newlines
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+from django.core.exceptions import SuspiciousOperation
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# Configuration for urlize() function.
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TRAILING_PUNCTUATION_CHARS = '.,:;!'
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@@ -34,6 +35,7 @@ _html_escapes = {
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}
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MAX_URL_LENGTH = 2048
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+MAX_STRIP_TAGS_DEPTH = 50
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@keep_lazy(str, SafeText)
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@@ -185,15 +187,19 @@ def _strip_once(value):
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@keep_lazy_text
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def strip_tags(value):
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"""Return the given HTML with all tags stripped."""
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- # Note: in typical case this loop executes _strip_once once. Loop condition
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- # is redundant, but helps to reduce number of executions of _strip_once.
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value = str(value)
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+ # Note: in typical case this loop executes _strip_once twice (the second
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+ # execution does not remove any more tags).
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+ strip_tags_depth = 0
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while '<' in value and '>' in value:
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+ if strip_tags_depth >= MAX_STRIP_TAGS_DEPTH:
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+ raise SuspiciousOperation
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new_value = _strip_once(value)
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if value.count('<') == new_value.count('<'):
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# _strip_once wasn't able to detect more tags.
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break
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value = new_value
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+ strip_tags_depth += 1
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return value
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diff --git a/tests/utils_tests/test_html.py b/tests/utils_tests/test_html.py
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index fdabb63..625511e 100644
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--- a/tests/utils_tests/test_html.py
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+++ b/tests/utils_tests/test_html.py
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@@ -8,6 +8,7 @@ from django.utils.html import (
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linebreaks, smart_urlquote, strip_spaces_between_tags, strip_tags, urlize,
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)
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from django.utils.safestring import mark_safe
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+from django.core.exceptions import SuspiciousOperation
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class TestUtilsHtml(SimpleTestCase):
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@@ -90,12 +91,18 @@ class TestUtilsHtml(SimpleTestCase):
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('<script>alert()</script>&h', 'alert()h'),
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('><!' + ('&' * 16000) + 'D', '><!' + ('&' * 16000) + 'D'),
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('X<<<<br>br>br>br>X', 'XX'),
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+ ("<" * 50 + "a>" * 50, ""),
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)
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for value, output in items:
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with self.subTest(value=value, output=output):
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self.check_output(strip_tags, value, output)
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self.check_output(strip_tags, lazystr(value), output)
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+ def test_strip_tags_suspicious_operation(self):
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+ value = "<" * 51 + "a>" * 51, "<a>"
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+ with self.assertRaises(SuspiciousOperation):
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+ strip_tags(value)
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+
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def test_strip_tags_files(self):
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# Test with more lengthy content (also catching performance regressions)
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for filename in ('strip_tags1.html', 'strip_tags2.txt'):
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--
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2.33.0
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