Skip to content

bpo-41909: Enable previously disabled recursion checks. #22536

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 1 commit into from
Oct 4, 2020
Merged

bpo-41909: Enable previously disabled recursion checks. #22536

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
10 changes: 10 additions & 0 deletions Lib/test/test_isinstance.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -303,6 +303,16 @@ def __bases__(self):

self.assertEqual(True, issubclass(B(), int))

def test_infinite_recursion_in_bases(self):
class X:
@property
def __bases__(self):
return self.__bases__

self.assertRaises(RecursionError, issubclass, X(), int)
self.assertRaises(RecursionError, issubclass, int, X())
self.assertRaises(RecursionError, isinstance, 1, X())


def blowstack(fxn, arg, compare_to):
# Make sure that calling isinstance with a deeply nested tuple for its
Expand Down
2 changes: 2 additions & 0 deletions Misc/NEWS.d/next/Core and Builtins/2020-10-04-10-55-12.bpo-41909.BqHPcm.rst
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,2 @@
Fixed stack overflow in :func:`issubclass` and :func:`isinstance` when
getting the ``__bases__`` attribute leads to infinite recursion.
2 changes: 0 additions & 2 deletions Objects/abstract.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -2336,9 +2336,7 @@ abstract_get_bases(PyObject *cls)
_Py_IDENTIFIER(__bases__);
PyObject *bases;

Py_ALLOW_RECURSION
(void)_PyObject_LookupAttrId(cls, &PyId___bases__, &bases);
Py_END_ALLOW_RECURSION
if (bases != NULL && !PyTuple_Check(bases)) {
Py_DECREF(bases);
return NULL;
Expand Down
2 changes: 0 additions & 2 deletions Objects/unicodeobject.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -15734,9 +15734,7 @@ PyUnicode_InternInPlace(PyObject **p)
}

PyObject *t;
Py_ALLOW_RECURSION
t = PyDict_SetDefault(interned, s, s);
Py_END_ALLOW_RECURSION

if (t == NULL) {
PyErr_Clear();
Expand Down