bpo-34899: Fix a possible assertion failure due to int_from_bytes_impl() (GH-9705)

ZackerySpytz · serhiy-storchaka · commit 7bb9cd0a6766 · 2018-10-06T00:02:23.000+03:00
The _PyLong_FromByteArray() call in int_from_bytes_impl() was
unchecked.
diff --git a/Objects/longobject.c b/Objects/longobject.c
@@ -5403,7 +5403,7 @@ int_from_bytes_impl(PyTypeObject *type, PyObject *bytes_obj,
         little_endian, is_signed);
     Py_DECREF(bytes);
 
-    if (type != &PyLong_Type) {
+    if (long_obj != NULL && type != &PyLong_Type) {
         Py_SETREF(long_obj, PyObject_CallFunctionObjArgs((PyObject *)type,
                                                          long_obj, NULL));
     }

Original file line number	Diff line number	Diff line change
`@@ -5403,7 +5403,7 @@ int_from_bytes_impl(PyTypeObject type, PyObject bytes_obj,`
`5403`	`5403`	`little_endian, is_signed);`
`5404`	`5404`	`Py_DECREF(bytes);`
`5405`	`5405`
`5406`		`- if (type != &PyLong_Type) {`
	`5406`	`+ if (long_obj != NULL && type != &PyLong_Type) {`
`5407`	`5407`	`Py_SETREF(long_obj, PyObject_CallFunctionObjArgs((PyObject *)type,`
`5408`	`5408`	`long_obj, NULL));`
`5409`	`5409`	`}`