Add a hack to block calls to certain introspected functions

This is useful for keeping people from using methods that only fail in
certain circumstances, by making them fail in all circumstances
instead.

https://bugzilla.gnome.org/show_bug.cgi?id=618918

diff --git a/js/ui/environment.js b/js/ui/environment.js
index 209cdc82277d3d6d6be8a0c71b7324cb5c8c66bf..67682d8fe0e225e5ca63d31761c8f9e0b85a2ab0 100644 (file)
--- a/js/ui/environment.js
+++ b/js/ui/environment.js
@@ -1,5 +1,6 @@
 /* -*- mode: js2; js2-basic-offset: 4; indent-tabs-mode: nil -*- */
 
+const Shell = imports.gi.Shell;
 const St = imports.gi.St;
 const Gettext_gtk20 = imports.gettext.domain('gtk20');
 
@@ -28,8 +29,34 @@ function _patchContainerClass(containerClass) {
     };
 }
 
-_patchContainerClass(St.BoxLayout);
-_patchContainerClass(St.Table);
+// Replace @method with something that throws an error instead
+function _blockMethod(method, replacement, reason) {
+    let match = method.match(/^(.+)\.([^.]+)$/);
+    if (!match)
+        throw new Error('Bad method name "' + method + '"');
+    let proto = 'imports.gi.' + match[1] + '.prototype';
+    let property = match[2];
+
+    if (!global.set_property_mutable(proto, property, true))
+        throw new Error('Bad method name "' + method + '"');
+
+    // eval() is evil in general, but we know it's safe here since
+    // set_property_mutable() would have failed if proto was
+    // malformed.
+    let node = eval(proto);
+
+    let msg = 'Do not use "' + method + '".';
+    if (replacement)
+        msg += ' Use "' + replacement + '" instead.';
+    if (reason)
+        msg += ' (' + reason + ')';
+
+    node[property] = function() {
+        throw new Error(msg);
+    };
+
+    global.set_property_mutable(proto, property, false);
+}
 
 function init() {
     Tweener.init();
@@ -39,4 +66,20 @@ function init() {
     if (Gettext_gtk20.gettext('default:LTR') == 'default:RTL') {
         St.Widget.set_default_direction(St.TextDirection.RTL);
     }
+
+    _patchContainerClass(St.BoxLayout);
+    _patchContainerClass(St.Table);
+
+    _blockMethod('Clutter.Event.get_state', 'Shell.get_event_state',
+                 'gjs\'s handling of Clutter.ModifierType is broken. See bug 597292.');
+    _blockMethod('Gdk.Display.get_pointer', 'global.get_pointer',
+                 'gjs\'s handling of Gdk.ModifierType is broken. See bug 597292.');
+    _blockMethod('Gdk.Window.get_pointer', 'global.get_pointer',
+                 'gjs\'s handling of Gdk.ModifierType is broken. See bug 597292.');
+
+    // Now close the back door to prevent extensions from trying to
+    // abuse it. We can't actually delete it since
+    // Shell.Global.prototype itself is read-only.
+    global.set_property_mutable('imports.gi.Shell.Global.prototype', 'set_property_mutable', true);
+    Shell.Global.prototype.set_property_mutable = undefined;
 }

diff --git a/src/shell-global.c b/src/shell-global.c
index 758af542e891349678a266b3f41a8d0ba617025e..5d61e41e2d069bd9d4a14a1a3935c80ae9ae2d47 100644 (file)
--- a/src/shell-global.c
+++ b/src/shell-global.c
@@ -1327,3 +1327,68 @@ shell_global_create_app_launch_context (ShellGlobal *global)
 
   return (GAppLaunchContext *)context;
 }
+
+/**
+ * shell_global_set_property_mutable:
+ * @global: the #ShellGlobal
+ * @object: the "path" to a JS object, starting from the root object.
+ *  (Eg, "global.stage" or "imports.gi.Gtk.Window.prototype")
+ * @property: a property on @object
+ * @mutable: %TRUE or %FALSE
+ *
+ * If @mutable is %TRUE, this clears the "permanent" and "readonly" flags
+ * on @property of @object. If @mutable is %FALSE, it sets them.
+ *
+ * You can use this to make it possible to modify properties that
+ * would otherwise be read-only from JavaScript.
+ *
+ * Return value: success or failure.
+ */
+gboolean
+shell_global_set_property_mutable (ShellGlobal *global,
+                                   const char  *object,
+                                   const char  *property,
+                                   gboolean     mutable)
+{
+  JSContext *context = gjs_context_get_native_context (global->js_context);
+  char **parts;
+  JSObject *obj;
+  jsval val = JSVAL_VOID;
+  int i;
+  jsuint attrs;
+  JSBool found;
+
+  JS_AddRoot (context, &val);
+
+  parts = g_strsplit (object, ".", -1);
+  obj = JS_GetGlobalObject (context);
+  for (i = 0; parts[i]; i++)
+    {
+      if (!JS_GetProperty (context, obj, parts[i], &val))
+        {
+          g_strfreev (parts);
+          JS_RemoveRoot (context, &val);
+          gjs_log_exception (context, NULL);
+          return FALSE;
+        }
+      obj = JSVAL_TO_OBJECT (val);
+    }
+  g_strfreev (parts);
+
+  if (!JS_GetPropertyAttributes (context, obj, property, &attrs, &found) || !found)
+    {
+      JS_RemoveRoot (context, &val);
+      gjs_log_exception (context, NULL);
+      return FALSE;
+    }
+
+  if (mutable)
+    attrs &= ~(JSPROP_PERMANENT | JSPROP_READONLY);
+  else
+    attrs |= (JSPROP_PERMANENT | JSPROP_READONLY);
+
+  JS_SetPropertyAttributes (context, obj, property, attrs, &found);
+
+  JS_RemoveRoot (context, &val);
+  return !gjs_log_exception (context, NULL);
+}

diff --git a/src/shell-global.h b/src/shell-global.h
index 5ac31d820ff01adcd71c25197e0571db0c0a8f1f..27c43be97fb2d30d4095465615a4613c800f8f26 100644 (file)
--- a/src/shell-global.h
+++ b/src/shell-global.h
@@ -96,6 +96,11 @@ guint32 shell_global_get_current_time (ShellGlobal *global);
 
 GAppLaunchContext *shell_global_create_app_launch_context (ShellGlobal *global);
 
+gboolean shell_global_set_property_mutable (ShellGlobal *global,
+                                            const char  *object,
+                                            const char  *property,
+                                            gboolean     mutable);
+
 G_END_DECLS
 
 #endif /* __SHELL_GLOBAL_H__ */