StandardTest.php

<?php

declare (strict_types=1);
namespace Drupal\Tests\editor\Unit\EditorXssFilter;

use Drupal\editor\EditorXssFilter\Standard;
use Drupal\Tests\UnitTestCase;
use Drupal\filter\Plugin\FilterInterface;
// cspell:ignore ascript attributename bgsound bscript ckers cript datafld
// cspell:ignore dataformatas datasrc dynsrc ession livescript msgbox nmouseover
// cspell:ignore noxss pression ript scri scriptlet unicoded vbscript

/**
 * @coversDefaultClass \Drupal\editor\EditorXssFilter\Standard
 * @group editor
 */
class StandardTest extends UnitTestCase {
    
    /**
     * The mocked text format configuration entity.
     *
     * @var \Drupal\filter\Entity\FilterFormat|\PHPUnit\Framework\MockObject\MockObject
     */
    protected $format;
    
    /**
     * {@inheritdoc}
     */
    protected function setUp() : void {
        parent::setUp();
        // Mock text format configuration entity object.
        $this->format = $this->getMockBuilder('\\Drupal\\filter\\Entity\\FilterFormat')
            ->disableOriginalConstructor()
            ->getMock();
        $this->format
            ->expects($this->any())
            ->method('getFilterTypes')
            ->willReturn([
            FilterInterface::TYPE_HTML_RESTRICTOR,
        ]);
        $restrictions = [
            'allowed' => [
                'p' => TRUE,
                'a' => TRUE,
                '*' => [
                    'style' => FALSE,
                    'on*' => FALSE,
                ],
            ],
        ];
        $this->format
            ->expects($this->any())
            ->method('getHtmlRestrictions')
            ->willReturn($restrictions);
    }
    
    /**
     * Provides test data for testFilterXss().
     *
     * @see \Drupal\Tests\editor\Unit\editor\EditorXssFilter\StandardTest::testFilterXss()
     */
    public static function providerTestFilterXss() {
        $data = [];
        $data[] = [
            '<p>Hello, world!</p><unknown>Pink Fairy Armadillo</unknown>',
            '<p>Hello, world!</p><unknown>Pink Fairy Armadillo</unknown>',
        ];
        $data[] = [
            '<p style="color:red">Hello, world!</p><unknown>Pink Fairy Armadillo</unknown>',
            '<p>Hello, world!</p><unknown>Pink Fairy Armadillo</unknown>',
        ];
        $data[] = [
            '<p>Hello, world!</p><unknown>Pink Fairy Armadillo</unknown><script>alert("evil");</script>',
            '<p>Hello, world!</p><unknown>Pink Fairy Armadillo</unknown>alert("evil");',
        ];
        $data[] = [
            '<p>Hello, world!</p><unknown>Pink Fairy Armadillo</unknown><a href="javascript:alert(1)">test</a>',
            '<p>Hello, world!</p><unknown>Pink Fairy Armadillo</unknown><a href="alert(1)">test</a>',
        ];
        // All cases listed on https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet
        // No Filter Evasion.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#No_Filter_Evasion
        $data[] = [
            '<SCRIPT SRC=http://ha.ckers.org/xss.js></SCRIPT>',
            '',
        ];
        // Image XSS using the JavaScript directive.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#Image_XSS_using_the_JavaScript_directive
        $data[] = [
            '<IMG SRC="javascript:alert(\'XSS\');">',
            '<IMG src="alert(&#039;XSS&#039;);">',
        ];
        // No quotes and no semicolon.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#No_quotes_and_no_semicolon
        $data[] = [
            '<IMG SRC=javascript:alert(\'XSS\')>',
            '<IMG>',
        ];
        // Case insensitive XSS attack vector.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#Case_insensitive_XSS_attack_vector
        $data[] = [
            '<IMG SRC=JaVaScRiPt:alert(\'XSS\')>',
            '<IMG>',
        ];
        // HTML entities.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#HTML_entities
        $data[] = [
            '<IMG SRC=javascript:alert("XSS")>',
            '<IMG>',
        ];
        // Grave accent obfuscation.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#Grave_accent_obfuscation
        $data[] = [
            '<IMG SRC=`javascript:alert("RSnake says, \'XSS\'")`>',
            '<IMG>',
        ];
        // Malformed A tags.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#Malformed_A_tags
        $data[] = [
            '<a onmouseover="alert(document.cookie)">xxs link</a>',
            '<a>xxs link</a>',
        ];
        $data[] = [
            '<a onmouseover=alert(document.cookie)>xxs link</a>',
            '<a>xxs link</a>',
        ];
        // Malformed IMG tags.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#Malformed_IMG_tags
        $data[] = [
            '<IMG """><SCRIPT>alert("XSS")</SCRIPT>">',
            '<IMG>alert("XSS")"&gt;',
        ];
        // fromCharCode.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#fromCharCode
        $data[] = [
            '<IMG SRC=javascript:alert(String.fromCharCode(88,83,83))>',
            '<IMG src="alert(String.fromCharCode(88,83,83))">',
        ];
        // Default SRC tag to get past filters that check SRC domain.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#Default_SRC_tag_to_get_past_filters_that_check_SRC_domain
        $data[] = [
            '<IMG SRC=# onmouseover="alert(\'xxs\')">',
            '<IMG src="#">',
        ];
        // Default SRC tag by leaving it empty.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#Default_SRC_tag_by_leaving_it_empty
        $data[] = [
            '<IMG SRC= onmouseover="alert(\'xxs\')">',
            '<IMG>',
        ];
        // Default SRC tag by leaving it out entirely.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#Default_SRC_tag_by_leaving_it_out_entirely
        $data[] = [
            '<IMG onmouseover="alert(\'xxs\')">',
            '<IMG>',
        ];
        // Decimal HTML character references.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#Decimal_HTML_character_references
        $data[] = [
            '<IMG SRC=&#106;&#97;&#118;&#97;&#115;&#99;&#114;&#105;&#112;&#116;&#58;&#97;&#108;&#101;&#114;&#116;&#40;&#39;&#88;&#83;&#83;&#39;&#41;>',
            '<IMG src="alert(&#039;XSS&#039;)">',
        ];
        // Decimal HTML character references without trailing semicolons.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#Decimal_HTML_character_references_without_trailing_semicolons
        $data[] = [
            '<IMG SRC=&#0000106&#0000097&#0000118&#0000097&#0000115&#0000099&#0000114&#0000105&#0000112&#0000116&#0000058&#0000097&#0000108&#0000101&#0000114&#0000116&#0000040&#0000039&#0000088&#0000083&#0000083&#0000039&#0000041>',
            '<IMG src="&amp;#0000106&amp;#0000097&amp;#0000118&amp;#0000097&amp;#0000115&amp;#0000099&amp;#0000114&amp;#0000105&amp;#0000112&amp;#0000116&amp;#0000058&amp;#0000097&amp;#0000108&amp;#0000101&amp;#0000114&amp;#0000116&amp;#0000040&amp;#0000039&amp;#0000088&amp;#0000083&amp;#0000083&amp;#0000039&amp;#0000041">',
        ];
        // Hexadecimal HTML character references without trailing semicolons.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#Hexadecimal_HTML_character_references_without_trailing_semicolons
        $data[] = [
            '<IMG SRC=&#x6A&#x61&#x76&#x61&#x73&#x63&#x72&#x69&#x70&#x74&#x3A&#x61&#x6C&#x65&#x72&#x74&#x28&#x27&#x58&#x53&#x53&#x27&#x29>',
            '<IMG src="&amp;#x6A&amp;#x61&amp;#x76&amp;#x61&amp;#x73&amp;#x63&amp;#x72&amp;#x69&amp;#x70&amp;#x74&amp;#x3A&amp;#x61&amp;#x6C&amp;#x65&amp;#x72&amp;#x74&amp;#x28&amp;#x27&amp;#x58&amp;#x53&amp;#x53&amp;#x27&amp;#x29">',
        ];
        // Embedded tab.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#Embedded_tab
        $data[] = [
            '<IMG SRC="jav  ascript:alert(\'XSS\');">',
            '<IMG src="alert(&#039;XSS&#039;);">',
        ];
        // Embedded Encoded tab.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#Embedded_Encoded_tab
        $data[] = [
            '<IMG SRC="jav&#x09;ascript:alert(\'XSS\');">',
            '<IMG src="alert(&#039;XSS&#039;);">',
        ];
        // Embedded newline to break up XSS.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#Embedded_newline_to_break_up_XSS
        $data[] = [
            '<IMG SRC="jav&#x0A;ascript:alert(\'XSS\');">',
            '<IMG src="alert(&#039;XSS&#039;);">',
        ];
        // Embedded carriage return to break up XSS.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#Embedded_carriage_return_to_break_up_XSS
        $data[] = [
            '<IMG SRC="jav&#x0D;ascript:alert(\'XSS\');">',
            '<IMG src="alert(&#039;XSS&#039;);">',
        ];
        // Null breaks up JavaScript directive.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#Null_breaks_up_JavaScript_directive
        $data[] = [
            "<IMG SRC=java\x00script:alert(\"XSS\")>",
            '<IMG>',
        ];
        // Non-alpha-non-digit XSS.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#Non-alpha-non-digit_XSS
        $data[] = [
            '<SCRIPT/XSS SRC="http://ha.ckers.org/xss.js"></SCRIPT>',
            '',
        ];
        $data[] = [
            '<BODY onload!#$%&()*~+-_.,:;?@[/|\\]^`=alert("XSS")>',
            '<BODY>',
        ];
        $data[] = [
            '<SCRIPT/SRC="http://ha.ckers.org/xss.js"></SCRIPT>',
            '',
        ];
        // Extraneous open brackets.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#Extraneous_open_brackets
        $data[] = [
            '<<SCRIPT>alert("XSS");//<</SCRIPT>',
            '&lt;alert("XSS");//&lt;',
        ];
        // No closing script tags.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#No_closing_script_tags
        $data[] = [
            '<SCRIPT SRC=http://ha.ckers.org/xss.js?< B >',
            '',
        ];
        // Protocol resolution in script tags.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#Protocol_resolution_in_script_tags
        $data[] = [
            '<SCRIPT SRC=//ha.ckers.org/.j>',
            '',
        ];
        // Half open HTML/JavaScript XSS vector.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#Half_open_HTML.2FJavaScript_XSS_vector
        $data[] = [
            '<IMG SRC="javascript:alert(\'XSS\')"',
            '<IMG src="alert(&#039;XSS&#039;)">',
        ];
        // Double open angle brackets.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#Double_open_angle_brackets
        // @see http://ha.ckers.org/blog/20060611/hotbot-xss-vulnerability/ to
        // understand why this is a vulnerability.
        $data[] = [
            '<iframe src=http://ha.ckers.org/scriptlet.html <',
            '<iframe src="http://ha.ckers.org/scriptlet.html">',
        ];
        // Escaping JavaScript escapes.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#Escaping_JavaScript_escapes
        // This one is irrelevant for Drupal; we *never* output any JavaScript code
        // that depends on the URL's query string.
        // End title tag.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#End_title_tag
        $data[] = [
            '</TITLE><SCRIPT>alert("XSS");</SCRIPT>',
            '</TITLE>alert("XSS");',
        ];
        // INPUT image.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#INPUT_image
        $data[] = [
            '<INPUT TYPE="IMAGE" SRC="javascript:alert(\'XSS\');">',
            '<INPUT type="IMAGE" src="alert(&#039;XSS&#039;);">',
        ];
        // BODY image.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#BODY_image
        $data[] = [
            '<BODY BACKGROUND="javascript:alert(\'XSS\')">',
            '<BODY background="alert(&#039;XSS&#039;)">',
        ];
        // IMG Dynsrc.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#IMG_Dynsrc
        $data[] = [
            '<IMG DYNSRC="javascript:alert(\'XSS\')">',
            '<IMG dynsrc="alert(&#039;XSS&#039;)">',
        ];
        // IMG lowsrc.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#IMG_lowsrc
        $data[] = [
            '<IMG LOWSRC="javascript:alert(\'XSS\')">',
            '<IMG lowsrc="alert(&#039;XSS&#039;)">',
        ];
        // List-style-image.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#List-style-image
        $data[] = [
            '<STYLE>li {list-style-image: url("javascript:alert(\'XSS\')");}</STYLE><UL><LI>XSS</br>',
            'li {list-style-image: url("javascript:alert(\'XSS\')");}<UL><LI>XSS</br>',
        ];
        // VBscript in an image.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#VBscript_in_an_image
        $data[] = [
            '<IMG SRC=\'vbscript:msgbox("XSS")\'>',
            '<IMG src=\'msgbox(&quot;XSS&quot;)\'>',
        ];
        // Livescript (older versions of Netscape only).
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#Livescript_.28older_versions_of_Netscape_only.29
        $data[] = [
            '<IMG SRC="livescript:[code]">',
            '<IMG src="[code]">',
        ];
        // BODY tag.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#BODY_tag
        $data[] = [
            '<BODY ONLOAD=alert(\'XSS\')>',
            '<BODY>',
        ];
        // Event handlers.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#Event_Handlers
        $events = [
            'onAbort',
            'onActivate',
            'onAfterPrint',
            'onAfterUpdate',
            'onBeforeActivate',
            'onBeforeCopy',
            'onBeforeCut',
            'onBeforeDeactivate',
            'onBeforeEditFocus',
            'onBeforePaste',
            'onBeforePrint',
            'onBeforeUnload',
            'onBeforeUpdate',
            'onBegin',
            'onBlur',
            'onBounce',
            'onCellChange',
            'onChange',
            'onClick',
            'onContextMenu',
            'onControlSelect',
            'onCopy',
            'onCut',
            'onDataAvailable',
            'onDataSetChanged',
            'onDataSetComplete',
            'onDblClick',
            'onDeactivate',
            'onDrag',
            'onDragEnd',
            'onDragLeave',
            'onDragEnter',
            'onDragOver',
            'onDragDrop',
            'onDragStart',
            'onDrop',
            'onEnd',
            'onError',
            'onErrorUpdate',
            'onFilterChange',
            'onFinish',
            'onFocus',
            'onFocusIn',
            'onFocusOut',
            'onHashChange',
            'onHelp',
            'onInput',
            'onKeyDown',
            'onKeyPress',
            'onKeyUp',
            'onLayoutComplete',
            'onLoad',
            'onLoseCapture',
            'onMediaComplete',
            'onMediaError',
            'onMessage',
            'onMousedown',
            'onMouseEnter',
            'onMouseLeave',
            'onMouseMove',
            'onMouseOut',
            'onMouseOver',
            'onMouseUp',
            'onMouseWheel',
            'onMove',
            'onMoveEnd',
            'onMoveStart',
            'onOffline',
            'onOnline',
            'onOutOfSync',
            'onPaste',
            'onPause',
            'onPopState',
            'onProgress',
            'onPropertyChange',
            'onReadyStateChange',
            'onRedo',
            'onRepeat',
            'onReset',
            'onResize',
            'onResizeEnd',
            'onResizeStart',
            'onResume',
            'onReverse',
            'onRowsEnter',
            'onRowExit',
            'onRowDelete',
            'onRowInserted',
            'onScroll',
            'onSeek',
            'onSelect',
            'onSelectionChange',
            'onSelectStart',
            'onStart',
            'onStop',
            'onStorage',
            'onSyncRestored',
            'onSubmit',
            'onTimeError',
            'onTrackChange',
            'onUndo',
            'onUnload',
            'onURLFlip',
        ];
        foreach ($events as $event) {
            $data[] = [
                '<p ' . $event . '="javascript:alert(\'XSS\');">Dangerous llama!</p>',
                '<p>Dangerous llama!</p>',
            ];
        }
        // BGSOUND.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#BGSOUND
        $data[] = [
            '<BGSOUND SRC="javascript:alert(\'XSS\');">',
            '<BGSOUND src="alert(&#039;XSS&#039;);">',
        ];
        // & JavaScript includes.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#.26_JavaScript_includes
        $data[] = [
            '<BR SIZE="&{alert(\'XSS\')}">',
            '<BR size="">',
        ];
        // STYLE sheet.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#STYLE_sheet
        $data[] = [
            '<LINK REL="stylesheet" HREF="javascript:alert(\'XSS\');">',
            '',
        ];
        // Remote style sheet.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#Remote_style_sheet
        $data[] = [
            '<LINK REL="stylesheet" HREF="http://ha.ckers.org/xss.css">',
            '',
        ];
        // Remote style sheet part 2.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#Remote_style_sheet_part_2
        $data[] = [
            '<STYLE>@import\'http://ha.ckers.org/xss.css\';</STYLE>',
            '@import\'http://ha.ckers.org/xss.css\';',
        ];
        // Remote style sheet part 3.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#Remote_style_sheet_part_3
        $data[] = [
            '<META HTTP-EQUIV="Link" Content="<http://ha.ckers.org/xss.css>; REL=stylesheet">',
            '<META http-equiv="Link">; REL=stylesheet"&gt;',
        ];
        // Remote style sheet part 4.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#Remote_style_sheet_part_4
        $data[] = [
            '<STYLE>BODY{-moz-binding:url("http://ha.ckers.org/xssmoz.xml#xss")}</STYLE>',
            'BODY{-moz-binding:url("http://ha.ckers.org/xssmoz.xml#xss")}',
        ];
        // STYLE tags with broken up JavaScript for XSS.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#STYLE_tags_with_broken_up_JavaScript_for_XSS
        $data[] = [
            '<STYLE>@im\\port\'\\ja\\vasc\\ript:alert("XSS")\';</STYLE>',
            '@im\\port\'\\ja\\vasc\\ript:alert("XSS")\';',
        ];
        // STYLE attribute using a comment to break up expression.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#STYLE_attribute_using_a_comment_to_break_up_expression
        $data[] = [
            '<IMG STYLE="xss:expr/*XSS*/ession(alert(\'XSS\'))">',
            '<IMG>',
        ];
        // IMG STYLE with expression.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#IMG_STYLE_with_expression
        $data[] = [
            'exp/*<A STYLE=\'no\\xss:noxss("*//*");
xss:ex/*XSS*//*/*/pression(alert("XSS"))\'>',
            'exp/*<A>',
        ];
        // STYLE tag (Older versions of Netscape only).
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#STYLE_tag_.28Older_versions_of_Netscape_only.29
        $data[] = [
            '<STYLE TYPE="text/javascript">alert(\'XSS\');</STYLE>',
            'alert(\'XSS\');',
        ];
        // STYLE tag using background-image.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#STYLE_tag_using_background-image
        $data[] = [
            '<STYLE>.XSS{background-image:url("javascript:alert(\'XSS\')");}</STYLE><A CLASS=XSS></A>',
            '.XSS{background-image:url("javascript:alert(\'XSS\')");}<A class="XSS"></A>',
        ];
        // STYLE tag using background.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#STYLE_tag_using_background
        $data[] = [
            '<STYLE type="text/css">BODY{background:url("javascript:alert(\'XSS\')")}</STYLE>',
            'BODY{background:url("javascript:alert(\'XSS\')")}',
        ];
        // Anonymous HTML with STYLE attribute.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#Anonymous_HTML_with_STYLE_attribute
        $data[] = [
            '<XSS STYLE="xss:expression(alert(\'XSS\'))">',
            '<XSS>',
        ];
        // Local htc file.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#Local_htc_file
        $data[] = [
            '<XSS STYLE="behavior: url(xss.htc);">',
            '<XSS>',
        ];
        // US-ASCII encoding.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#US-ASCII_encoding
        // This one is irrelevant for Drupal; Drupal *always* outputs UTF-8.
        // META.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#META
        $data[] = [
            '<META HTTP-EQUIV="refresh" CONTENT="0;url=javascript:alert(\'XSS\');">',
            '<META http-equiv="refresh" content="alert(&#039;XSS&#039;);">',
        ];
        // META using data.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#META_using_data
        $data[] = [
            '<META HTTP-EQUIV="refresh" CONTENT="0;url=data:text/html base64,PHNjcmlwdD5hbGVydCgnWFNTJyk8L3NjcmlwdD4K">',
            '<META http-equiv="refresh" content="text/html base64,PHNjcmlwdD5hbGVydCgnWFNTJyk8L3NjcmlwdD4K">',
        ];
        // META with additional URL parameter
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#META
        $data[] = [
            '<META HTTP-EQUIV="refresh" CONTENT="0; URL=http://;URL=javascript:alert(\'XSS\');">',
            '<META http-equiv="refresh" content="//;URL=javascript:alert(&#039;XSS&#039;);">',
        ];
        // IFRAME.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#IFRAME
        $data[] = [
            '<IFRAME SRC="javascript:alert(\'XSS\');"></IFRAME>',
            '<IFRAME src="alert(&#039;XSS&#039;);"></IFRAME>',
        ];
        // IFRAME Event based.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#IFRAME_Event_based
        $data[] = [
            '<IFRAME SRC=# onmouseover="alert(document.cookie)"></IFRAME>',
            '<IFRAME src="#"></IFRAME>',
        ];
        // FRAME.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#FRAME
        $data[] = [
            '<FRAMESET><FRAME SRC="javascript:alert(\'XSS\');"></FRAMESET>',
            '<FRAMESET><FRAME src="alert(&#039;XSS&#039;);"></FRAMESET>',
        ];
        // TABLE.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#TABLE
        $data[] = [
            '<TABLE BACKGROUND="javascript:alert(\'XSS\')">',
            '<TABLE background="alert(&#039;XSS&#039;)">',
        ];
        // TD.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#TD
        $data[] = [
            '<TABLE><TD BACKGROUND="javascript:alert(\'XSS\')">',
            '<TABLE><TD background="alert(&#039;XSS&#039;)">',
        ];
        // DIV background-image.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#DIV_background-image
        $data[] = [
            '<DIV STYLE="background-image: url(javascript:alert(\'XSS\'))">',
            '<DIV>',
        ];
        // DIV background-image with unicoded XSS exploit.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#DIV_background-image_with_unicoded_XSS_exploit
        $data[] = [
            '<DIV STYLE="background-image:\\0075\\0072\\006C\\0028\'\\006a\\0061\\0076\\0061\\0073\\0063\\0072\\0069\\0070\\0074\\003a\\0061\\006c\\0065\\0072\\0074\\0028.1027\\0058.1053\\0053\\0027\\0029\'\\0029">',
            '<DIV>',
        ];
        // DIV background-image plus extra characters.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#DIV_background-image_plus_extra_characters
        $data[] = [
            '<DIV STYLE="background-image: url(&#1;javascript:alert(\'XSS\'))">',
            '<DIV>',
        ];
        // DIV expression.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#DIV_expression
        $data[] = [
            '<DIV STYLE="width: expression(alert(\'XSS\'));">',
            '<DIV>',
        ];
        // Downlevel-Hidden block.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#Downlevel-Hidden_block
        $data[] = [
            '<!--[if gte IE 4]>
 <SCRIPT>alert(\'XSS\');</SCRIPT>
 <![endif]-->',
            "\n alert('XSS');\n ",
        ];
        // BASE tag.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#BASE_tag
        $data[] = [
            '<BASE HREF="javascript:alert(\'XSS\');//">',
            '<BASE href="alert(&#039;XSS&#039;);//">',
        ];
        // OBJECT tag.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#OBJECT_tag
        $data[] = [
            '<OBJECT TYPE="text/x-scriptlet" DATA="http://ha.ckers.org/scriptlet.html"></OBJECT>',
            '',
        ];
        // Using an EMBED tag you can embed a Flash movie that contains XSS.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#Using_an_EMBED_tag_you_can_embed_a_Flash_movie_that_contains_XSS
        $data[] = [
            '<EMBED SRC="http://ha.ckers.org/xss.swf" AllowScriptAccess="always"></EMBED>',
            '',
        ];
        // You can EMBED SVG which can contain your XSS vector.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#You_can_EMBED_SVG_which_can_contain_your_XSS_vector
        // cspell:disable-next-line
        $data[] = [
            '<EMBED SRC="data:image/svg+xml;base64,PHN2ZyB4bWxuczpzdmc9Imh0dH A6Ly93d3cudzMub3JnLzIwMDAvc3ZnIiB4bWxucz0iaHR0cDovL3d3dy53My5vcmcv MjAwMC9zdmciIHhtbG5zOnhsaW5rPSJodHRwOi8vd3d3LnczLm9yZy8xOTk5L3hs aW5rIiB2ZXJzaW9uPSIxLjAiIHg9IjAiIHk9IjAiIHdpZHRoPSIxOTQiIGhlaWdodD0iMjAw IiBpZD0ieHNzIj48c2NyaXB0IHR5cGU9InRleHQvZWNtYXNjcmlwdCI+YWxlcnQoIlh TUyIpOzwvc2NyaXB0Pjwvc3ZnPg==" type="image/svg+xml" AllowScriptAccess="always"></EMBED>',
            '',
        ];
        // XML data island with CDATA obfuscation.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#XML_data_island_with_CDATA_obfuscation
        $data[] = [
            '<XML ID="xss"><I><B><IMG SRC="javas<!-- -->cript:alert(\'XSS\')"></B></I></XML><SPAN DATASRC="#xss" DATAFLD="B" DATAFORMATAS="HTML"></SPAN>',
            '<XML id="xss"><I><B><IMG>cript:alert(\'XSS\')"&gt;</B></I></XML><SPAN datasrc="#xss" datafld="B" dataformatas="HTML"></SPAN>',
        ];
        // Locally hosted XML with embedded JavaScript that is generated using an XML data island.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#Locally_hosted_XML_with_embedded_JavaScript_that_is_generated_using_an_XML_data_island
        // This one is irrelevant for Drupal; Drupal disallows XML uploads by
        // default.
        // HTML+TIME in XML.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#HTML.2BTIME_in_XML
        $data[] = [
            '<?xml:namespace prefix="t" ns="urn:schemas-microsoft-com:time"><?import namespace="t" implementation="#default#time2"><t:set attributeName="innerHTML" to="XSS<SCRIPT DEFER>alert("XSS")</SCRIPT>">',
            '&lt;?xml:namespace prefix="t" ns="urn:schemas-microsoft-com:time"&gt;&lt;?import namespace="t" implementation="#default#time2"&gt;<t set attributename="innerHTML">alert("XSS")"&gt;',
        ];
        // Assuming you can only fit in a few characters and it filters against ".js".
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#Assuming_you_can_only_fit_in_a_few_characters_and_it_filters_against_.22.js.22
        $data[] = [
            '<SCRIPT SRC="http://ha.ckers.org/xss.jpg"></SCRIPT>',
            '',
        ];
        // IMG Embedded commands.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#IMG_Embedded_commands
        // This one is irrelevant for Drupal; this is actually a CSRF, for which
        // Drupal has CSRF protection. See https://www.drupal.org/node/178896.
        // Cookie manipulation.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#Cookie_manipulation
        $data[] = [
            '<META HTTP-EQUIV="Set-Cookie" Content="USERID=<SCRIPT>alert(\'XSS\')</SCRIPT>">',
            '<META http-equiv="Set-Cookie">alert(\'XSS\')"&gt;',
        ];
        // UTF-7 encoding.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#UTF-7_encoding
        // This one is irrelevant for Drupal; Drupal *always* outputs UTF-8.
        // XSS using HTML quote encapsulation.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#XSS_using_HTML_quote_encapsulation
        $data[] = [
            '<SCRIPT a=">" SRC="http://ha.ckers.org/xss.js"></SCRIPT>',
            '" SRC="http://ha.ckers.org/xss.js"&gt;',
        ];
        $data[] = [
            '<SCRIPT =">" SRC="http://ha.ckers.org/xss.js"></SCRIPT>',
            '" SRC="http://ha.ckers.org/xss.js"&gt;',
        ];
        $data[] = [
            '<SCRIPT a=">" \'\' SRC="http://ha.ckers.org/xss.js"></SCRIPT>',
            '" \'\' SRC="http://ha.ckers.org/xss.js"&gt;',
        ];
        $data[] = [
            '<SCRIPT "a=\'>\'" SRC="http://ha.ckers.org/xss.js"></SCRIPT>',
            '\'" SRC="http://ha.ckers.org/xss.js"&gt;',
        ];
        $data[] = [
            '<SCRIPT a=`>` SRC="http://ha.ckers.org/xss.js"></SCRIPT>',
            '` SRC="http://ha.ckers.org/xss.js"&gt;',
        ];
        $data[] = [
            '<SCRIPT a=">\'>" SRC="http://ha.ckers.org/xss.js"></SCRIPT>',
            '\'&gt;" SRC="http://ha.ckers.org/xss.js"&gt;',
        ];
        $data[] = [
            '<SCRIPT>document.write("<SCRI");</SCRIPT>PT SRC="http://ha.ckers.org/xss.js"></SCRIPT>',
            'document.write("<SCRI>PT SRC="http://ha.ckers.org/xss.js"&gt;',
        ];
        // URL string evasion.
        // @see https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#URL_string_evasion
        // This one is irrelevant for Drupal; Drupal doesn't forbid linking to some
        // sites, it only forbids linking to any protocols other than those that are
        // whitelisted.
        // Test XSS filtering on data-attributes.
        // @see \Drupal\editor\EditorXssFilter::filterXssDataAttributes()
        // The following two test cases verify that XSS attack vectors are filtered.
        $data[] = [
            '<img src="butterfly.jpg" data-caption="&lt;script&gt;alert();&lt;/script&gt;" />',
            '<img src="butterfly.jpg" data-caption="alert();">',
        ];
        $data[] = [
            '<img src="butterfly.jpg" data-caption="&lt;EMBED SRC=&quot;http://ha.ckers.org/xss.swf&quot; AllowScriptAccess=&quot;always&quot;&gt;&lt;/EMBED&gt;" />',
            '<img src="butterfly.jpg" data-caption>',
        ];
        // When including HTML-tags as visible content, they are double-escaped.
        // This test case ensures that we leave that content unchanged.
        $data[] = [
            '<img src="butterfly.jpg" data-caption="&amp;lt;script&amp;gt;alert();&amp;lt;/script&amp;gt;" />',
            '<img src="butterfly.jpg" data-caption="&amp;lt;script&amp;gt;alert();&amp;lt;/script&amp;gt;">',
        ];
        return $data;
    }
    
    /**
     * Tests the method for filtering XSS.
     *
     * @param string $input
     *   The input.
     * @param string $expected_output
     *   The expected output.
     *
     * @dataProvider providerTestFilterXss
     */
    public function testFilterXss($input, $expected_output) {
        $output = Standard::filterXss($input, $this->format);
        $this->assertSame($expected_output, $output);
    }
    
    /**
     * Tests removing disallowed tags and XSS prevention.
     *
     * \Drupal\Component\Utility\Xss::filter() has the ability to run in blacklist
     * mode, in which it still applies the exact same filtering, with one
     * exception: it no longer works with a list of allowed tags, but with a list
     * of disallowed tags.
     *
     * @param string $value
     *   The value to filter.
     * @param string $expected
     *   The string that is expected to be missing.
     * @param string $message
     *   The assertion message to display upon failure.
     * @param array $disallowed_tags
     *   (optional) The disallowed HTML tags to be passed to \Drupal\Component\Utility\Xss::filter().
     *
     * @dataProvider providerTestBlackListMode
     */
    public function testBlacklistMode($value, $expected, $message, array $disallowed_tags) {
        $value = Standard::filter($value, $disallowed_tags);
        $this->assertSame($expected, $value, $message);
    }
    
    /**
     * Data provider for testBlacklistMode().
     *
     * @see testBlacklistMode()
     *
     * @return array
     *   An array of arrays containing the following elements:
     *     - The value to filter.
     *     - The value to expect after filtering.
     *     - The assertion message.
     *     - (optional) The disallowed HTML tags to be passed to \Drupal\Component\Utility\Xss::filter().
     */
    public static function providerTestBlackListMode() {
        return [
            [
                '<unknown style="visibility:hidden">Pink Fairy Armadillo</unknown><video src="gerenuk.mp4"><script>alert(0)</script>',
                '<unknown>Pink Fairy Armadillo</unknown><video src="gerenuk.mp4">alert(0)',
                'Disallow only the script tag',
                [
                    'script',
                ],
            ],
            [
                '<unknown style="visibility:hidden">Pink Fairy Armadillo</unknown><video src="gerenuk.mp4"><script>alert(0)</script>',
                '<unknown>Pink Fairy Armadillo</unknown>alert(0)',
                'Disallow both the script and video tags',
                [
                    'script',
                    'video',
                ],
            ],
            // No real use case for this, but it is an edge case we must ensure works.
[
                '<unknown style="visibility:hidden">Pink Fairy Armadillo</unknown><video src="gerenuk.mp4"><script>alert(0)</script>',
                '<unknown>Pink Fairy Armadillo</unknown><video src="gerenuk.mp4"><script>alert(0)</script>',
                'Disallow no tags',
                [],
            ],
        ];
    }

}