Issue #28322: Fixed possible crashes when unpickle itertools objects from

incorrect pickle data.  Based on patch by John Leitch.

Lib/test/test_itertools.py

@@ -183,6 +183,19 @@ class TestBasicOps(unittest.TestCase):
         for proto in range(pickle.HIGHEST_PROTOCOL + 1):
             self.pickletest(proto, chain('abc', 'def'), compare=list('abcdef'))
 
+    def test_chain_setstate(self):
+        self.assertRaises(TypeError, chain().__setstate__, ())
+        self.assertRaises(TypeError, chain().__setstate__, [])
+        self.assertRaises(TypeError, chain().__setstate__, 0)
+        self.assertRaises(TypeError, chain().__setstate__, ([],))
+        self.assertRaises(TypeError, chain().__setstate__, (iter([]), []))
+        it = chain()
+        it.__setstate__((iter(['abc', 'def']),))
+        self.assertEqual(list(it), ['a', 'b', 'c', 'd', 'e', 'f'])
+        it = chain()
+        it.__setstate__((iter(['abc', 'def']), iter(['ghi'])))
+        self.assertEqual(list(it), ['ghi', 'a', 'b', 'c', 'd', 'e', 'f'])
+
     def test_combinations(self):
         self.assertRaises(TypeError, combinations, 'abc')       # missing r argument
         self.assertRaises(TypeError, combinations, 'abc', 2, 1) # too many arguments
@@ -667,19 +680,22 @@ class TestBasicOps(unittest.TestCase):
         self.assertEqual(take(20, c), list('defgabcdefgabcdefgab'))
 
         # The first argument to setstate needs to be a tuple
-        with self.assertRaises(SystemError):
+        with self.assertRaises(TypeError):
             cycle('defg').__setstate__([list('abcdefg'), 0])
 
         # The first argument in the setstate tuple must be a list
         with self.assertRaises(TypeError):
             c = cycle('defg')
-            c.__setstate__((dict.fromkeys('defg'), 0))
-            take(20, c)
+            c.__setstate__((tuple('defg'), 0))
+        take(20, c)
 
-        # The first argument in the setstate tuple must be a list
+        # The second argument in the setstate tuple must be an int
         with self.assertRaises(TypeError):
             cycle('defg').__setstate__((list('abcdefg'), 'x'))
 
+        self.assertRaises(TypeError, cycle('').__setstate__, ())
+        self.assertRaises(TypeError, cycle('').__setstate__, ([],))
+
     def test_groupby(self):
         # Check whether it accepts arguments correctly
         self.assertEqual([], list(groupby([])))

Misc/NEWS

@@ -54,6 +54,9 @@ Core and Builtins
 Library
 -------
 
+- Issue #28322: Fixed possible crashes when unpickle itertools objects from
+  incorrect pickle data.  Based on patch by John Leitch.
+
 - Issue #28228: imghdr now supports pathlib.
 
 - Issue #28226: compileall now supports pathlib.

Modules/itertoolsmodule.c

@@ -147,8 +147,13 @@ static PyObject *
 groupby_setstate(groupbyobject *lz, PyObject *state)
 {
     PyObject *currkey, *currvalue, *tgtkey;
-    if (!PyArg_ParseTuple(state, "OOO", &currkey, &currvalue, &tgtkey))
+    if (!PyTuple_Check(state)) {
+        PyErr_SetString(PyExc_TypeError, "state is not a tuple");
         return NULL;
+    }
+    if (!PyArg_ParseTuple(state, "OOO", &currkey, &currvalue, &tgtkey)) {
+        return NULL;
+    }
     Py_INCREF(currkey);
     Py_XSETREF(lz->currkey, currkey);
     Py_INCREF(currvalue);
@@ -727,8 +732,13 @@ tee_setstate(teeobject *to, PyObject *state)
 {
     teedataobject *tdo;
     int index;
-    if (!PyArg_ParseTuple(state, "O!i", &teedataobject_type, &tdo, &index))
+    if (!PyTuple_Check(state)) {
+        PyErr_SetString(PyExc_TypeError, "state is not a tuple");
         return NULL;
+    }
+    if (!PyArg_ParseTuple(state, "O!i", &teedataobject_type, &tdo, &index)) {
+        return NULL;
+    }
     if (index < 0 || index > LINKCELLS) {
         PyErr_SetString(PyExc_ValueError, "Index out of range");
         return NULL;
@@ -971,9 +981,13 @@ cycle_setstate(cycleobject *lz, PyObject *state)
 {
     PyObject *saved=NULL;
     int firstpass;
-
-    if (!PyArg_ParseTuple(state, "O!i", &PyList_Type, &saved, &firstpass))
+    if (!PyTuple_Check(state)) {
+        PyErr_SetString(PyExc_TypeError, "state is not a tuple");
         return NULL;
+    }
+    if (!PyArg_ParseTuple(state, "O!i", &PyList_Type, &saved, &firstpass)) {
+        return NULL;
+    }
     Py_INCREF(saved);
     Py_XSETREF(lz->saved, saved);
     lz->firstpass = firstpass != 0;
@@ -1903,8 +1917,17 @@ chain_setstate(chainobject *lz, PyObject *state)
 {
     PyObject *source, *active=NULL;
 
-    if (! PyArg_ParseTuple(state, "O|O", &source, &active))
+    if (!PyTuple_Check(state)) {
+        PyErr_SetString(PyExc_TypeError, "state is not a tuple");
         return NULL;
+    }
+    if (!PyArg_ParseTuple(state, "O|O", &source, &active)) {
+        return NULL;
+    }
+    if (!PyIter_Check(source) || (active != NULL && !PyIter_Check(active))) {
+        PyErr_SetString(PyExc_TypeError, "Arguments must be iterators.");
+        return NULL;
+    }
 
     Py_INCREF(source);
     Py_XSETREF(lz->source, source);
@@ -3262,10 +3285,15 @@ permutations_setstate(permutationsobject *po, PyObject *state)
     PyObject *indices, *cycles, *result;
     Py_ssize_t n, i;
 
+    if (!PyTuple_Check(state)) {
+        PyErr_SetString(PyExc_TypeError, "state is not a tuple");
+        return NULL;
+    }
     if (!PyArg_ParseTuple(state, "O!O!",
                           &PyTuple_Type, &indices,
-                          &PyTuple_Type, &cycles))
+                          &PyTuple_Type, &cycles)) {
         return NULL;
+    }
 
     n = PyTuple_GET_SIZE(po->pool);
     if (PyTuple_GET_SIZE(indices) != n || PyTuple_GET_SIZE(cycles) != po->r) {