From 772a73f70c3d249c99c23012849e66276b7b0715 Mon Sep 17 00:00:00 2001 From: Mariusz Felisiak Date: Wed, 10 Jul 2024 20:30:12 +0200 Subject: [PATCH 3/4] [4.2.x] Fixed CVE-2024-41991 -- Prevented potential ReDoS in django.utils.html.urlize() and AdminURLFieldWidget. Thanks Seokchan Yoon for the report. Co-authored-by: Sarah Boyce <42296566+sarahboyce@users.noreply.github.com> --- django/contrib/admin/widgets.py | 2 +- django/utils/html.py | 10 ++++++++-- tests/admin_widgets/tests.py | 7 ++++++- tests/utils_tests/test_html.py | 13 +++++++++++++ 5 files changed, 35 insertions(+), 4 deletions(-) Index: Django-2.2.28/django/contrib/admin/widgets.py =================================================================== --- Django-2.2.28.orig/django/contrib/admin/widgets.py +++ Django-2.2.28/django/contrib/admin/widgets.py @@ -344,7 +344,7 @@ class AdminURLFieldWidget(forms.URLInput context = super().get_context(name, value, attrs) context['current_label'] = _('Currently:') context['change_label'] = _('Change:') - context['widget']['href'] = smart_urlquote(context['widget']['value']) if value else '' + context['widget']['href'] = smart_urlquote(context['widget']['value']) if url_valid else '' context['url_valid'] = url_valid return context Index: Django-2.2.28/django/utils/html.py =================================================================== --- Django-2.2.28.orig/django/utils/html.py +++ Django-2.2.28/django/utils/html.py @@ -33,6 +33,8 @@ _html_escapes = { ord("'"): ''', } +MAX_URL_LENGTH = 2048 + @keep_lazy(str, SafeText) def escape(text): @@ -360,6 +362,10 @@ def urlize(text, trim_url_limit=None, no except ValueError: # value contains more than one @. return False + # Max length for domain name labels is 63 characters per RFC 1034. + # Helps to avoid ReDoS vectors in the domain part. + if len(p2) > 63: + return False # Dot must be in p2 (e.g. example.com) if '.' not in p2 or p2.startswith('.'): return False @@ -378,9 +384,9 @@ def urlize(text, trim_url_limit=None, no # Make URL we want to point to. url = None nofollow_attr = ' rel="nofollow"' if nofollow else '' - if simple_url_re.match(middle): + if len(middle) <= MAX_URL_LENGTH and simple_url_re.match(middle): url = smart_urlquote(unescape(middle)) - elif simple_url_2_re.match(middle): + elif len(middle) <= MAX_URL_LENGTH and simple_url_2_re.match(middle): url = smart_urlquote('http://%s' % unescape(middle)) elif ':' not in middle and is_email_simple(middle): local, domain = middle.rsplit('@', 1) Index: Django-2.2.28/tests/admin_widgets/tests.py =================================================================== --- Django-2.2.28.orig/tests/admin_widgets/tests.py +++ Django-2.2.28/tests/admin_widgets/tests.py @@ -336,7 +336,12 @@ class AdminSplitDateTimeWidgetTest(Simpl class AdminURLWidgetTest(SimpleTestCase): def test_get_context_validates_url(self): w = widgets.AdminURLFieldWidget() - for invalid in ['', '/not/a/full/url/', 'javascript:alert("Danger XSS!")']: + for invalid in [ + "", + "/not/a/full/url/", + 'javascript:alert("Danger XSS!")', + "http://" + "한.글." * 1_000_000 + "com", + ]: with self.subTest(url=invalid): self.assertFalse(w.get_context('name', invalid, {})['url_valid']) self.assertTrue(w.get_context('name', 'http://example.com', {})['url_valid']) Index: Django-2.2.28/tests/utils_tests/test_html.py =================================================================== --- Django-2.2.28.orig/tests/utils_tests/test_html.py +++ Django-2.2.28/tests/utils_tests/test_html.py @@ -261,6 +261,10 @@ class TestUtilsHtml(SimpleTestCase): def test_urlize_unchanged_inputs(self): tests = ( ("a" + "@a" * 50000) + "a", # simple_email_re catastrophic test + # Unicode domain catastrophic tests. + "a@" + "한.글." * 1_000_000 + "a", + "http://" + "한.글." * 1_000_000 + "com", + "www." + "한.글." * 1_000_000 + "com", ("a" + "." * 1000000) + "a", # trailing_punctuation catastrophic test "foo@", "@foo.com",