From aaa9cb5ec616be36a2385ca027d9a1e9d0158841 Mon Sep 17 00:00:00 2001
From: Brian Wolff <bawolff+wn@gmail.com>
Date: Mon, 26 Sep 2016 10:40:30 +0000
Subject: [PATCH] SECURITY: XSS in search if $wgAdvancedSearchHighlighting =
 true;

In the non-default configuration where $wgAdvancedSearchHighlighting
is set to true, there is an XSS vulnerability as HTML tags are
not properly escaped if the tag spans multiple search results

Issue introduced in abf726ea0 (MediaWiki 1.13 and above).

Bug: T144845
Change-Id: I2db7888d591b97f1a01bfd3b7567ce6f169874d3
---
 includes/search/SearchHighlighter.php | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/includes/search/SearchHighlighter.php b/includes/search/SearchHighlighter.php
index d0e3a24..cebdb40 100644
--- a/includes/search/SearchHighlighter.php
+++ b/includes/search/SearchHighlighter.php
@@ -29,6 +29,10 @@
 class SearchHighlighter {
 	protected $mCleanWikitext = true;
 
+	/**
+	 * @warning If you pass false to this constructor, then
+	 *  the caller is responsible for HTML escaping.
+	 */
 	function __construct( $cleanupWikitext = true ) {
 		$this->mCleanWikitext = $cleanupWikitext;
 	}
@@ -456,6 +460,10 @@ class SearchHighlighter {
 		$text = preg_replace( "/('''|<\/?[iIuUbB]>)/", "", $text );
 		$text = preg_replace( "/''/", "", $text );
 
+		// Note, the previous /<\/?[^>]+>/ is insufficient
+		// for XSS safety as the HTML tag can span multiple
+		// search results (T144845).
+		$text = Sanitizer::escapeHtmlAllowEntities( $text );
 		return $text;
 	}
 
-- 
1.9.5 (Apple Git-50.3)

