Fix vulnerability in handling _session argument of utils/save-prefs (#1489382)

CHANGELOG

@@ -1,6 +1,7 @@
 CHANGELOG Roundcube Webmail
 ===========================
 
+- Fix vulnerability in handling _session argument of utils/save-prefs (#1489382)
 - Fix iframe onload for upload errors handling (#1489379)
 - Fix address matching in Return-Path header on identity selection (#1489374)
 - Fix HTML part detection when encapsulated inside multipart/signed (#1489372)

program/lib/Roundcube/rcube_plugin_api.php

@@ -37,6 +37,7 @@ class rcube_plugin_api
     public $output;
     public $handlers              = array();
     public $allowed_prefs         = array();
+    public $allowed_session_prefs = array();
 
     protected $plugins = array();
     protected $tasks = array();

program/steps/utils/save_pref.inc

@@ -5,7 +5,7 @@
  | program/steps/utils/save_pref.inc                                     |
  |                                                                       |
  | This file is part of the Roundcube Webmail client                     |
- | Copyright (C) 2005-2010, The Roundcube Dev Team                       |
+ | Copyright (C) 2005-2013, The Roundcube Dev Team                       |
  |                                                                       |
  | Licensed under the GNU General Public License version 3 or            |
  | any later version with exceptions for skins & plugins.                |
@@ -21,14 +21,24 @@
 
 $name     = get_input_value('_name', RCUBE_INPUT_POST);
 $value    = get_input_value('_value', RCUBE_INPUT_POST);
+$sessname = get_input_value('_session', RCUBE_INPUT_POST);
+
+// Whitelisted preferences and session variables, others
+// can be added by plugins
 $whitelist = array(
     'preview_pane',
     'list_cols',
     'collapsed_folders',
     'collapsed_abooks',
 );
+$whitelist_sess = array(
+    'list_attrib/columns',
+);
+
+$whitelist      = array_merge($whitelist, $RCMAIL->plugins->allowed_prefs);
+$whitelist_sess = array_merge($whitelist_sess, $RCMAIL->plugins->allowed_session_prefs);
 
-if (!in_array($name, array_merge($whitelist, $RCMAIL->plugins->allowed_prefs))) {
+if (!in_array($name, $whitelist) || ($sessname && !in_array($sessname, $whitelist_sess))) {
     raise_error(array('code' => 500, 'type' => 'php',
         'file' => __FILE__, 'line' => __LINE__,
         'message' => sprintf("Hack attempt detected (user: %s)", $RCMAIL->get_user_name())),
@@ -42,7 +52,7 @@ if (!in_array($name, array_merge($whitelist, $RCMAIL->plugins->allowed_prefs)))
 $RCMAIL->user->save_prefs(array($name => $value));
 
 // update also session if requested
-if ($sessname = get_input_value('_session', RCUBE_INPUT_POST)) {
+if ($sessname) {
     // Support multidimensional arrays...
     $vars = explode('/', $sessname);
 
@@ -57,5 +67,3 @@ if ($sessname = get_input_value('_session', RCUBE_INPUT_POST)) {
 
 $OUTPUT->reset();
 $OUTPUT->send();
-
-