From f43668a17eb746b725a94247039739ba3c0c4e36 Mon Sep 17 00:00:00 2001
From: Brad Jorsch <bjorsch@wikimedia.org>
Date: Mon, 14 Mar 2016 11:48:20 -0400
Subject: [PATCH] SECURITY: Don't escape strip markers when escaping attributes
 in mw.html

Core strip markers were changed in T110143 to include characters that
are normally encoded in attributes, however we want to pass them through
here so they can be unstripped correctly in the output wikitext.

This fix makes "Strip markers in CSS" parser test pass again.

Change-Id: I1353931a53c668d8a453dfa2300a99f59fdb01c5
---
 engines/LuaCommon/HtmlLibrary.php            |  8 ++++++-
 engines/LuaCommon/lualib/mw.html.lua         | 34 +++++++++++++++++++++-------
 tests/engines/LuaCommon/HtmlLibraryTest.php  | 14 ++++++++++++
 tests/engines/LuaCommon/HtmlLibraryTests.lua | 12 ++++++++++
 4 files changed, 59 insertions(+), 9 deletions(-)

diff --git a/engines/LuaCommon/HtmlLibrary.php b/engines/LuaCommon/HtmlLibrary.php
index 5b413d8..a606eb1 100644
--- a/engines/LuaCommon/HtmlLibrary.php
+++ b/engines/LuaCommon/HtmlLibrary.php
@@ -2,6 +2,12 @@
 
 class Scribunto_LuaHtmlLibrary extends Scribunto_LuaLibraryBase {
 	function register() {
-		return $this->getEngine()->registerInterface( 'mw.html.lua', array() );
+		return $this->getEngine()->registerInterface( 'mw.html.lua', array(), array(
+			// Prior to 1.26, the Parser sets its prefix as,
+			// $this->mUniqPrefix = "\x7f'\"`UNIQ" . self::getRandomString()
+			// random part should be hex chars, so we only need the first part here
+			'uniqPrefix' => "\x7f'\"`UNIQ",
+			'uniqSuffix' => Parser::MARKER_SUFFIX,
+		) );
 	}
 }
diff --git a/engines/LuaCommon/lualib/mw.html.lua b/engines/LuaCommon/lualib/mw.html.lua
index 7411de5..2e58e98 100644
--- a/engines/LuaCommon/lualib/mw.html.lua
+++ b/engines/LuaCommon/lualib/mw.html.lua
@@ -14,6 +14,7 @@
 ]]
 
 local HtmlBuilder = {}
+local options
 
 local util = require 'libraryUtil'
 local checkType = util.checkType
@@ -87,7 +88,11 @@ end
 -- @param s
 local function htmlEncode( s )
 	-- The parentheses ensure that there is only one return value
-	return ( string.gsub( s, '[<>&"]', htmlencodeMap ) )
+	local tmp = string.gsub( s, '[<>&"]', htmlencodeMap );
+	-- Don't encode strip markers here (T110143)
+	tmp = string.gsub( tmp, options.encodedUniqPrefixPat, options.uniqPrefixRepl )
+	tmp = string.gsub( tmp, options.encodedUniqSuffixPat, options.uniqSuffixRepl )
+	return tmp
 end
 
 local function cssEncode( s )
@@ -401,12 +406,25 @@ function HtmlBuilder.create( tagName, args )
 	return createBuilder( tagName, args )
 end
 
-mw_interface = nil
-
--- Register this library in the "mw" global
-mw = mw or {}
-mw.html = HtmlBuilder
-
-package.loaded['mw.html'] = HtmlBuilder
+function HtmlBuilder.setupInterface( opts )
+	-- Boilerplate
+	HtmlBuilder.setupInterface = nil
+	mw_interface = nil
+	options = opts
+
+	-- Prepare patterns for unencoding strip markers
+	options.encodedUniqPrefixPat = string.gsub( options.uniqPrefix, '[<>&"]', htmlencodeMap );
+	options.encodedUniqPrefixPat = string.gsub( options.encodedUniqPrefixPat, '%p', '%%%0' );
+	options.uniqPrefixRepl = string.gsub( options.uniqPrefix, '%%', '%%%0' );
+	options.encodedUniqSuffixPat = string.gsub( options.uniqSuffix, '[<>&"]', htmlencodeMap );
+	options.encodedUniqSuffixPat = string.gsub( options.encodedUniqSuffixPat, '%p', '%%%0' );
+	options.uniqSuffixRepl = string.gsub( options.uniqSuffix, '%%', '%%%0' );
+
+	-- Register this library in the "mw" global
+	mw = mw or {}
+	mw.html = HtmlBuilder
+
+	package.loaded['mw.html'] = HtmlBuilder
+end
 
 return HtmlBuilder
diff --git a/tests/engines/LuaCommon/HtmlLibraryTest.php b/tests/engines/LuaCommon/HtmlLibraryTest.php
index 5b47962..8e3076e 100644
--- a/tests/engines/LuaCommon/HtmlLibraryTest.php
+++ b/tests/engines/LuaCommon/HtmlLibraryTest.php
@@ -3,6 +3,20 @@
 class Scribunto_LuaHtmlLibraryTests extends Scribunto_LuaEngineTestBase {
 	protected static $moduleName = 'HtmlLibraryTests';
 
+	protected function setUp() {
+		parent::setUp();
+
+		// For strip marker test
+		$markers = array(
+			'nowiki' => "\x7f'\"`UNIQ" . '-test-nowiki-' . Parser::MARKER_SUFFIX,
+		);
+		$interpreter = $this->getEngine()->getInterpreter();
+		$interpreter->callFunction(
+			$interpreter->loadString( 'mw.html.stripMarkers = ...', 'fortest' ),
+			$markers
+		);
+	}
+
 	protected function getTestModules() {
 		return parent::getTestModules() + array(
 			'HtmlLibraryTests' => __DIR__ . '/HtmlLibraryTests.lua',
diff --git a/tests/engines/LuaCommon/HtmlLibraryTests.lua b/tests/engines/LuaCommon/HtmlLibraryTests.lua
index f7ebfaf..e9ea123 100644
--- a/tests/engines/LuaCommon/HtmlLibraryTests.lua
+++ b/tests/engines/LuaCommon/HtmlLibraryTests.lua
@@ -101,6 +101,15 @@ local function testComplex()
 	return builder
 end
 
+local function testStripMarker()
+	local expect = '<div foo="' .. mw.html.stripMarkers.nowiki .. '"></div>'
+	local actual = tostring( getEmptyTestDiv():attr( 'foo', mw.html.stripMarkers.nowiki ) )
+	if actual ~= expect then
+		error( actual .. ' ~= ' .. expect )
+	end
+	return 'ok'
+end
+
 -- Tests
 local tests = {
 	-- Simple (inline) tests
@@ -342,6 +351,9 @@ local tests = {
 		'<hr /><div abc="def" style="width:-1px"></div></div>'
 	  }
 	},
+	{ name = 'mw.html strip marker test', func = testStripMarker, type='ToString',
+	  expect = { 'ok' }
+	},
 }
 
 return testframework.getTestProvider( tests )
-- 
2.6.6