GH-141312: Allow only integers to longrangeiter_setstate state

Lib/test/test_range.py

@@ -470,6 +470,32 @@ def test_iterator_setstate(self):
         it.__setstate__(2**64 - 7)
         self.assertEqual(list(it), [12, 10])
 
+        class I:
+            def __index__(self): return 2
+            def __repr__(self): return "I()"
+
+        it = iter(range(10, 20, 2))
+        it.__setstate__(I())
+        self.assertEqual(list(it), [14, 16, 18])
+
+    def test_rangeiter_invalid_setstate(self):
+        for invalid_value in (1.0, ""):
+            with self.subTest(invalid_value=invalid_value):
+                it = iter(range(10, 100, 2))
+                with self.assertRaises(TypeError):
+                    it.__setstate__(invalid_value)
+
+    def test_longrangeiter_invalid_setstate(self):
+        class I:
+            def __index__(self): return 1
+            def __repr__(self): return "I()"
+
+        for invalid_value in (1.0, "", I()):
+            with self.subTest(invalid_value=invalid_value):
+                it = iter(range(10, 2**65, 2))
+                with self.assertRaises(TypeError):
+                    it.__setstate__(invalid_value)
+
     def test_odd_bug(self):
         # This used to raise a "SystemError: NULL result without error"
         # because the range validation step was eating the exception

Misc/NEWS.d/next/Core_and_Builtins/2025-11-10-23-07-06.gh-issue-141312.H-58GB.rst

@@ -0,0 +1,2 @@
+Restrict passing of non-integer object to the ``longrangeiter.__setstate__``.
+Patch by Sergey Miryanov.

Objects/rangeobject.c

@@ -1042,6 +1042,11 @@ longrangeiter_reduce(PyObject *op, PyObject *Py_UNUSED(ignored))
 static PyObject *
 longrangeiter_setstate(PyObject *op, PyObject *state)
 {
+    if (!PyLong_CheckExact(state)) {
+        PyErr_Format(PyExc_TypeError, "state must be an int, not %T", state);
+        return NULL;
+    }
+
     longrangeiterobject *r = (longrangeiterobject*)op;
     PyObject *zero = _PyLong_GetZero();  // borrowed reference
     int cmp;