[gnome-shell] shell/window-tracker: Match on WM_CLASS first

[Florian Müllner <fmuellner src gnome org>]

commit f29dbd1f187fc78f0afc938faee7f7f2713635c4
Author: Florian Müllner <fmuellner gnome org>
Date:   Fri Jul 3 17:34:23 2020 +0200

    shell/window-tracker: Match on WM_CLASS first
    
    Currently our heuristics for matching a window to its app check
    for the application ID before the WM_CLASS, as the ID is more
    reliable in so far that it is outside the application's control
    and so it cannot use it to spoof a different application.
    
    However this also prevents applications with multiple .desktop
    files like LibreOffice from matching any .desktop files other
    than the one under the main ID.
    
    Since we now no longer allow the WM_CLASS to match a .desktop
    file that doesn't belong to the sandboxed application, we can
    fix that issue by checking the WM_CLASS first, without opening
    the door to spoofing.
    
    https://gitlab.gnome.org/GNOME/gnome-shell/issues/219

 src/shell-window-tracker.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)
---
diff --git a/src/shell-window-tracker.c b/src/shell-window-tracker.c
index 5548fb5e56..e754dde8ec 100644
--- a/src/shell-window-tracker.c
+++ b/src/shell-window-tracker.c
@@ -402,6 +402,13 @@ get_app_for_window (ShellWindowTracker    *tracker,
   if (meta_window_is_remote (window))
     return _shell_app_new_for_window (window);
 
+  /* Check if the app's WM_CLASS specifies an app; this is
+   * canonical if it does.
+   */
+  result = get_app_from_window_wmclass (window);
+  if (result != NULL)
+    return result;
+
   /* Check if the window was opened from within a sandbox; if this
    * is the case, a corresponding .desktop file is guaranteed to match;
    */
@@ -416,13 +423,6 @@ get_app_for_window (ShellWindowTracker    *tracker,
   if (result != NULL)
     return result;
 
-  /* Check if the app's WM_CLASS specifies an app; this is
-   * canonical if it does.
-   */
-  result = get_app_from_window_wmclass (window);
-  if (result != NULL)
-    return result;
-
   result = get_app_from_window_pid (tracker, window);
   if (result != NULL)
     return result;