ScreenShield: don't allow events through the lock dialog

Make the lock dialog group reactive, to intercept any events
before they go to the actors below.
In the future, we may restructure our chrome to have a clear
layer system, but for now it fixes a security issue in the lock
screen (you can see the contents of the windows by dragging
if the screen was locked with the overview active)

https://bugzilla.gnome.org/show_bug.cgi?id=705840

diff --git a/js/ui/screenShield.js b/js/ui/screenShield.js
index 5e7693cd0d4946271534b3fb284a7982a575b68f..910462a1f98399047ab689115e39306f199bc045 100644 (file)
--- a/js/ui/screenShield.js
+++ b/js/ui/screenShield.js
@@ -518,6 +518,7 @@ const ScreenShield = new Lang.Class({
 
         this._lockDialogGroup = new St.Widget({ x_expand: true,
                                                 y_expand: true,
+                                                reactive: true,
                                                 opacity: 0,
                                                 pivot_point: new Clutter.Point({ x: 0.5, y: 0.5 }),
                                                 name: 'lockDialogGroup' });