[mutter] wayland/xdg-shell: Check popup parent type when assigning

[Jonas Ådahl <jadahl src gnome org>]

commit c533a06e93e5eb70aae70900ded384646c4861c7
Author: Jonas Ådahl <jadahl gmail com>
Date:   Wed Nov 15 16:03:36 2017 +0800

    wayland/xdg-shell: Check popup parent type when assigning
    
    We only allow mapping popups on top of surfaces with a xdg_surface
    based role. Add a check and fail clients that doesn't follow this rule.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=790358

 src/wayland/meta-wayland-xdg-shell.c |    8 ++++++++
 1 files changed, 8 insertions(+), 0 deletions(-)
---
diff --git a/src/wayland/meta-wayland-xdg-shell.c b/src/wayland/meta-wayland-xdg-shell.c
index 5ca39b3..8bb2ec7 100644
--- a/src/wayland/meta-wayland-xdg-shell.c
+++ b/src/wayland/meta-wayland-xdg-shell.c
@@ -1553,6 +1553,14 @@ xdg_surface_constructor_get_popup (struct wl_client   *client,
       return;
     }
 
+  if (!META_IS_WAYLAND_XDG_SURFACE (parent_surface->role))
+    {
+      wl_resource_post_error (xdg_shell_resource,
+                              ZXDG_SHELL_V6_ERROR_INVALID_POPUP_PARENT,
+                              "Invalid popup parent role");
+      return;
+    }
+
   xdg_popup = META_WAYLAND_XDG_POPUP (surface->role);
   xdg_popup->resource = wl_resource_create (client,
                                             &zxdg_popup_v6_interface,