gh-126461: Fix _Unpickler_ReadFromFile() error handling (#126485)

vstinner · web-flow · commit a1c57bcfd2bc · 2024-11-06T14:24:46.000+01:00
Handle _Unpickler_SetStringInput() failure.
diff --git a/Modules/_pickle.c b/Modules/_pickle.c
@@ -1288,6 +1288,10 @@ _Unpickler_ReadFromFile(UnpicklerObject *self, Py_ssize_t n)
             else {
                 read_size = _Unpickler_SetStringInput(self, data);
                 Py_DECREF(data);
+                if (read_size < 0) {
+                    return -1;
+                }
+
                 self->prefetched_idx = 0;
                 if (n <= read_size)
                     return n;
