view: assert internal signals are disconnected before destroy

If they are not empty, then we are headed for use-after-free shortly.
An assert() failure is easier to debug than UAF, so let's fail early.

Inspired by:
https://gitlab.freedesktop.org/wlroots/wlroots/-/commit/8f56f7ca43257cc05c7c4eb57a0f541e05cf9a79

diff --git a/src/view.c b/src/view.c
index 95cafc809eb0fef61ba5cb59afb4a2734050b7e3..33b92444c8e5d0d54c5297fda86592d3579f0d09 100644 (file)
--- a/src/view.c
+++ b/src/view.c
@@ -2684,6 +2684,16 @@ view_destroy(struct view *view)
                view->scene_tree = NULL;
        }
 
+       assert(wl_list_empty(&view->events.new_app_id.listener_list));
+       assert(wl_list_empty(&view->events.new_title.listener_list));
+       assert(wl_list_empty(&view->events.new_outputs.listener_list));
+       assert(wl_list_empty(&view->events.maximized.listener_list));
+       assert(wl_list_empty(&view->events.minimized.listener_list));
+       assert(wl_list_empty(&view->events.fullscreened.listener_list));
+       assert(wl_list_empty(&view->events.activated.listener_list));
+       assert(wl_list_empty(&view->events.set_icon.listener_list));
+       assert(wl_list_empty(&view->events.destroy.listener_list));
+
        /* Remove view from server->views */
        wl_list_remove(&view->link);
        free(view);