From 8493b59c2b8d7afabd3aa598bf79fc8930f6ad53 Mon Sep 17 00:00:00 2001
From: Gabriel Jenik <gabriel.jenik@gmail.com>
Date: Thu, 12 Nov 2020 05:01:18 -0300
Subject: [PATCH] New feature #12560: enable video in spite of active xss
 filtering (#1589)

Dev Added new configuration to the HtmlPurifier.
Dev Extended the standard HtmlPurifier so it exposes the config in a public method.
---
 application/core/LSYii_HtmlPurifier.php | 94 +++++++++++++++++++++++++
 application/core/LSYii_Validators.php   | 20 +-----
 2 files changed, 95 insertions(+), 19 deletions(-)
 create mode 100644 application/core/LSYii_HtmlPurifier.php

diff --git a/application/core/LSYii_HtmlPurifier.php b/application/core/LSYii_HtmlPurifier.php
new file mode 100644
index 00000000000..794d0a52bfe
--- /dev/null
+++ b/application/core/LSYii_HtmlPurifier.php
@@ -0,0 +1,94 @@
+<?php if (!defined('BASEPATH')) {
+    exit('No direct script access allowed');
+}
+/*
+ * LimeSurvey
+ * Copyright (C) 2007-2011 The LimeSurvey Project Team / Carsten Schmitz
+ * All rights reserved.
+ * License: GNU/GPL License v2 or later, see LICENSE.php
+ * LimeSurvey is free software. This version may have been modified pursuant
+ * to the GNU General Public License, and as distributed it includes or
+ * is derivative of works licensed under the GNU General Public License or
+ * other free or open source software licenses.
+ * See COPYRIGHT.php for copyright notices and details.
+ *
+ */
+
+class LSYii_HtmlPurifier extends CHtmlPurifier
+{
+
+    /**
+	 * Get the config object for the HTML Purifier instance.
+	 * @return mixed the HTML Purifier instance config
+	 */
+	public function getConfig()
+	{
+        $purifier = $this->getPurifier();
+		if($purifier!==null) return $purifier->config;
+	}
+
+	/**
+	 * Get an instance of LSYii_HtmlPurifier configured for XSS filtering
+	 */
+	public static function getXssPurifier() {
+		$instance = new self();
+		$instance->options = array(
+            'AutoFormat.RemoveEmpty'=>false,
+            'Core.NormalizeNewlines'=>false,
+            'CSS.AllowTricky'=>true, // Allow display:none; (and other)
+            'HTML.SafeObject'=>true, // To allow including youtube
+            'Output.FlashCompat'=>true,
+            'Attr.EnableID'=>true, // Allow to set id
+            'Attr.AllowedFrameTargets'=>array('_blank', '_self'),
+            'URI.AllowedSchemes'=>array(
+                'http' => true,
+                'https' => true,
+                'mailto' => true,
+                'ftp' => true,
+                'nntp' => true,
+                'news' => true,
+                )
+        );
+        // To allow script BUT purify : HTML.Trusted=true (plugin idea for admin or without XSS filtering ?)
+
+        // Enable video
+        $config = $instance->getConfig();
+        if (!empty($config)) {
+            $config->set('HTML.DefinitionID', 'html5-definitions');
+            $def = $config->maybeGetRawHTMLDefinition();
+            $max = $config->get('HTML.MaxImgLength');
+            if ($def) {
+            $def->addElement(
+                    'video',   // name
+                    'Inline',  // content set
+                    'Flow', // allowed children
+                    'Common', // attribute collection
+                    array( // attributes
+                        'src' => 'URI',
+                'id' => 'Text',
+                    'poster' => 'Text',
+                        'width' => 'Pixels#' . $max,
+                        'height' => 'Pixels#' . $max,
+                        'controls' => 'Bool#controls',
+                        'autobuffer' => 'Bool#autobuffer',
+                        'autoplay' => 'Bool#autoplay',
+                        'loop' => 'Bool#loop',
+                        'muted' => 'Bool#muted'
+                    )
+                );
+                $def->addElement(
+                    'source',   // name
+                    'Inline',  // content set
+                    'Empty', // allowed children
+                    null, // attribute collection
+                    array( // attributes
+                        'src*' => 'URI',
+                        'type' => 'Enum#video/mp4,video/webm',
+                    )
+                );
+            }
+		}
+		
+		return $instance;
+	}
+}
diff --git a/application/core/LSYii_Validators.php b/application/core/LSYii_Validators.php
index cd96a5d6c55..436de4eaa76 100644
--- a/application/core/LSYii_Validators.php
+++ b/application/core/LSYii_Validators.php
@@ -108,25 +108,7 @@ public function fixCKeditor($value)
      */
     public function xssFilter($value)
     {
-        $filter = new CHtmlPurifier();
-        $filter->options = array(
-            'AutoFormat.RemoveEmpty'=>false,
-            'Core.NormalizeNewlines'=>false,
-            'CSS.AllowTricky'=>true, // Allow display:none; (and other)
-            'HTML.SafeObject'=>true, // To allow including youtube
-            'Output.FlashCompat'=>true,
-            'Attr.EnableID'=>true, // Allow to set id
-            'Attr.AllowedFrameTargets'=>array('_blank', '_self'),
-            'URI.AllowedSchemes'=>array(
-                'http' => true,
-                'https' => true,
-                'mailto' => true,
-                'ftp' => true,
-                'nntp' => true,
-                'news' => true,
-                )
-        );
-        // To allow script BUT purify : HTML.Trusted=true (plugin idea for admin or without XSS filtering ?)
+        $filter = LSYii_HtmlPurifier::getXssPurifier();
 
         /** Start to get complete filtered value with  url decode {QCODE} (bug #09300). This allow only question number in url, seems OK with XSS protection **/
         $sFiltered = preg_replace('#%7B([a-zA-Z0-9\.]*)%7D#', '{$1}', $filter->purify($value));