From c676b05c98df58252509dd5ad16b959c351ac770 Mon Sep 17 00:00:00 2001 From: nkrapp Date: Fri, 26 Jul 2024 14:01:36 +0200 Subject: [PATCH] Fixed CVE-2024-39329 -- Standarized timing of verify_password() when checking unusuable passwords. Refs #20760. Thanks Michael Manfre for the fix and to Adam Johnson for the review. --- django/contrib/auth/hashers.py | 10 ++++++++-- tests/auth_tests/test_hashers.py | 22 ++++++++++++++++++++++ 2 files changed, 30 insertions(+), 2 deletions(-) diff --git a/django/contrib/auth/hashers.py b/django/contrib/auth/hashers.py index 1e8d7547fc..af55e57389 100644 --- a/django/contrib/auth/hashers.py +++ b/django/contrib/auth/hashers.py @@ -36,14 +36,20 @@ def check_password(password, encoded, setter=None, preferred='default'): If setter is specified, it'll be called when you need to regenerate the password. """ - if password is None or not is_password_usable(encoded): - return False + fake_runtime = password is None or not is_password_usable(encoded) preferred = get_hasher(preferred) try: hasher = identify_hasher(encoded) except ValueError: # encoded is gibberish or uses a hasher that's no longer installed. + fake_runtime = True + + if fake_runtime: + # Run the default password hasher once to reduce the timing difference + # between an existing user with an unusable password and a nonexistent + # user or missing hasher (similar to #20760). + make_password(get_random_string(UNUSABLE_PASSWORD_SUFFIX_LENGTH)) return False hasher_changed = hasher.algorithm != preferred.algorithm diff --git a/tests/auth_tests/test_hashers.py b/tests/auth_tests/test_hashers.py index ee6441b237..170bd07c4b 100644 --- a/tests/auth_tests/test_hashers.py +++ b/tests/auth_tests/test_hashers.py @@ -433,6 +433,28 @@ class TestUtilsHashPass(SimpleTestCase): check_password('wrong_password', encoded) self.assertEqual(hasher.harden_runtime.call_count, 1) + def test_check_password_calls_make_password_to_fake_runtime(self): + hasher = get_hasher("default") + cases = [ + (None, None, None), # no plain text password provided + ("foo", make_password(password=None), None), # unusable encoded + ("letmein", make_password(password="letmein"), ValueError), # valid encoded + ] + for password, encoded, hasher_side_effect in cases: + with self.subTest(encoded=encoded): + with mock.patch("django.contrib.auth.hashers.identify_hasher", side_effect=hasher_side_effect) as mock_identify_hasher: + with mock.patch("django.contrib.auth.hashers.make_password") as mock_make_password: + with mock.patch("django.contrib.auth.hashers.get_random_string", side_effect=lambda size: "x" * size): + with mock.patch.object(hasher, "verify"): + # Ensure make_password is called to standardize timing. + check_password(password, encoded) + self.assertEqual(hasher.verify.call_count, 0) + self.assertEqual(mock_identify_hasher.mock_calls, [mock.call(encoded)]) + self.assertEqual( + mock_make_password.mock_calls, + [mock.call("x" * UNUSABLE_PASSWORD_SUFFIX_LENGTH)], + ) + class BasePasswordHasherTests(SimpleTestCase): not_implemented_msg = 'subclasses of BasePasswordHasher must provide %s() method' -- 2.45.2