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

Conflicts:

	CHANGELOG
	program/lib/Roundcube/rcube_plugin_api.php
	program/steps/utils/save_pref.inc

CHANGELOG

@@ -1,6 +1,8 @@
 CHANGELOG Roundcube Webmail
 ===========================
 
+- Fix vulnerability in handling _session argument of utils/save-prefs (#1489382)
+
 RELEASE 0.7.4
 -------------
 - Fix security issue in save-pref command

program/include/rcube_plugin_api.php

@@ -27,13 +27,14 @@
 class rcube_plugin_api
 {
   static private $instance;
-  
+
   public $dir;
   public $url = 'plugins/';
   public $output;
   public $config;
-  public $allowed_prefs = array();
-  
+  public $allowed_prefs         = array();
+  public $allowed_session_prefs = array();
+
   public $handlers = array();
   private $plugins = array();
   private $tasks = array();

program/steps/utils/save_pref.inc

@@ -16,16 +16,26 @@
  +-----------------------------------------------------------------------+
 */
 
-$name = get_input_value('_name', RCUBE_INPUT_POST);
-$value = get_input_value('_value', RCUBE_INPUT_POST);
+$name     = get_input_value('_name', RCUBE_INPUT_POST);
+$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',
+);
 
-if (!in_array($name, array_merge($whitelist, $RCMAIL->plugins->allowed_prefs))) {
+$whitelist      = array_merge($whitelist, $RCMAIL->plugins->allowed_prefs);
+$whitelist_sess = array_merge($whitelist_sess, $RCMAIL->plugins->allowed_session_prefs);
+
+if (!in_array($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)", $_SESSION['username'])),
@@ -39,7 +49,7 @@ if (!in_array($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);
 
@@ -54,4 +64,3 @@ if ($sessname = get_input_value('_session', RCUBE_INPUT_POST)) {
 
 $OUTPUT->reset();
 $OUTPUT->send();
-