screenShield: Do not lock the screen when locked down

When using the 'disable-lock-screen' setting to lock down the screen
lock, the expectation is that users cannot lock the screen. However
as it turns out, all the setting currently does is hiding the lock
button in the system menu and making the lock settings in the privacy
panel inactive. That means that if the 'lock-screen-enabled' setting
isn't disabled and locked down as well, we will just continue to
lock the screen on inactivity - not to mention the keyboard shortcut
that isn't subject to that setting anyway.

Instead of expecting administrators to hunt down every possible way
of locking the screen and disabling it individually, we can easily
handle all cases by refusing to lock the screen when disabled by the
lockdown settings.

https://bugzilla.gnome.org/show_bug.cgi?id=780212

diff --git a/js/ui/screenShield.js b/js/ui/screenShield.js
index a2f0bf42744262959f7eed7333c85c32c1c1665e..fd21fdeeeb5fcbd86da0c12c47630ccaba20168b 100644 (file)
--- a/js/ui/screenShield.js
+++ b/js/ui/screenShield.js
@@ -33,6 +33,9 @@ const SCREENSAVER_SCHEMA = 'org.gnome.desktop.screensaver';
 const LOCK_ENABLED_KEY = 'lock-enabled';
 const LOCK_DELAY_KEY = 'lock-delay';
 
+const LOCKDOWN_SCHEMA = 'org.gnome.desktop.lockdown';
+const DISABLE_LOCK_KEY = 'disable-lock-screen';
+
 const LOCKED_STATE_STR = 'screenShield.locked';
 // fraction of screen height the arrow must reach before completing
 // the slide up automatically
@@ -541,6 +544,8 @@ const ScreenShield = new Lang.Class({
         this._settings = new Gio.Settings({ schema_id: SCREENSAVER_SCHEMA });
         this._settings.connect('changed::' + LOCK_ENABLED_KEY, Lang.bind(this, this._syncInhibitor));
 
+        this._lockSettings = new Gio.Settings({ schema_id: LOCKDOWN_SCHEMA });
+
         this._isModal = false;
         this._hasLockScreen = false;
         this._isGreeter = false;
@@ -1290,6 +1295,11 @@ const ScreenShield = new Lang.Class({
     },
 
     lock: function(animate) {
+        if (this._lockSettings.get_boolean(DISABLE_LOCK_KEY)) {
+            log('Screen lock is locked down, not locking') // lock, lock - who's there?
+            return;
+        }
+
         // Warn the user if we can't become modal
         if (!this._becomeModal()) {
             Main.notifyError(_("Unable to lock"),