62 lines
2.5 KiB
Diff
62 lines
2.5 KiB
Diff
From 048a9ebb6ea468426cb4e57c71572cbbd975517f Mon Sep 17 00:00:00 2001
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From: Mariusz Felisiak <felisiak.mariusz@gmail.com>
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Date: Tue, 17 Oct 2023 11:48:32 +0200
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Subject: [PATCH] [4.2.x] Fixed CVE-2023-46695 -- Fixed potential DoS in
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UsernameField on Windows.
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Thanks MProgrammer (https://hackerone.com/mprogrammer) for the report.
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---
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django/contrib/auth/forms.py | 10 +++++++++-
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tests/auth_tests/test_forms.py | 7 +++++++
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2 files changed, 16 insertions(+), 1 deletion(-)
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diff --git a/django/contrib/auth/forms.py b/django/contrib/auth/forms.py
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index eaae0bf..061dc81 100644
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--- a/django/contrib/auth/forms.py
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+++ b/django/contrib/auth/forms.py
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@@ -71,7 +71,15 @@ class ReadOnlyPasswordHashField(forms.Field):
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class UsernameField(forms.CharField):
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def to_python(self, value):
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- return unicodedata.normalize("NFKC", super().to_python(value))
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+ value = super().to_python(value)
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+ if self.max_length is not None and len(value) > self.max_length:
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+ # Normalization can increase the string length (e.g.
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+ # "ff" -> "ff", "½" -> "1⁄2") but cannot reduce it, so there is no
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+ # point in normalizing invalid data. Moreover, Unicode
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+ # normalization is very slow on Windows and can be a DoS attack
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+ # vector.
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+ return value
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+ return unicodedata.normalize("NFKC", value)
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def widget_attrs(self, widget):
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return {
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diff --git a/tests/auth_tests/test_forms.py b/tests/auth_tests/test_forms.py
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index 7a80adb..81c56a4 100644
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--- a/tests/auth_tests/test_forms.py
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+++ b/tests/auth_tests/test_forms.py
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@@ -14,6 +14,7 @@ from django.contrib.auth.forms import (
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SetPasswordForm,
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UserChangeForm,
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UserCreationForm,
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+ UsernameField,
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)
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from django.contrib.auth.models import User
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from django.contrib.auth.signals import user_login_failed
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@@ -154,6 +155,12 @@ class BaseUserCreationFormTest(TestDataMixin, TestCase):
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self.assertNotEqual(user.username, ohm_username)
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self.assertEqual(user.username, "testΩ") # U+03A9 GREEK CAPITAL LETTER OMEGA
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+ def test_invalid_username_no_normalize(self):
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+ field = UsernameField(max_length=254)
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+ # Usernames are not normalized if they are too long.
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+ self.assertEqual(field.to_python("½" * 255), "½" * 255)
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+ self.assertEqual(field.to_python("ff" * 254), "ff" * 254)
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+
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def test_duplicate_normalized_unicode(self):
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"""
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To prevent almost identical usernames, visually identical but differing
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--
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2.30.0
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