71 lines
2.1 KiB
PHP
71 lines
2.1 KiB
PHP
|
<?php namespace BookStack\Util;
|
||
|
|
|
||
|
|
use DOMDocument;
|
||
|
|
use DOMNode;
|
||
|
|
use DOMNodeList;
|
||
|
|
use DOMXPath;
|
||
|
|
|
||
|
|
class HtmlContentFilter
|
||
|
|
{
|
||
|
|
/**
|
||
|
|
* Remove all of the script elements from the given HTML.
|
||
|
|
*/
|
||
|
|
public static function removeScripts(string $html): string
|
||
|
|
{
|
||
|
|
if (empty($html)) {
|
||
|
|
return $html;
|
||
|
|
}
|
||
|
|
|
||
|
|
libxml_use_internal_errors(true);
|
||
|
|
$doc = new DOMDocument();
|
||
|
|
$doc->loadHTML(mb_convert_encoding($html, 'HTML-ENTITIES', 'UTF-8'));
|
||
|
|
$xPath = new DOMXPath($doc);
|
||
|
|
|
||
|
|
// Remove standard script tags
|
||
|
|
$scriptElems = $xPath->query('//script');
|
||
|
|
static::removeNodes($scriptElems);
|
||
|
|
|
||
|
|
// Remove clickable links to JavaScript URI
|
||
|
|
$badLinks = $xPath->query('//*[contains(@href, \'javascript:\')]');
|
||
|
|
static::removeNodes($badLinks);
|
||
|
|
|
||
|
|
// Remove forms with calls to JavaScript URI
|
||
|
|
$badForms = $xPath->query('//*[contains(@action, \'javascript:\')] | //*[contains(@formaction, \'javascript:\')]');
|
||
|
|
static::removeNodes($badForms);
|
||
|
|
|
||
|
|
// Remove meta tag to prevent external redirects
|
||
|
|
$metaTags = $xPath->query('//meta[contains(@content, \'url\')]');
|
||
|
|
static::removeNodes($metaTags);
|
||
|
|
|
||
|
|
// Remove data or JavaScript iFrames
|
||
|
|
$badIframes = $xPath->query('//*[contains(@src, \'data:\')] | //*[contains(@src, \'javascript:\')] | //*[@srcdoc]');
|
||
|
|
static::removeNodes($badIframes);
|
||
|
|
|
||
|
|
// Remove 'on*' attributes
|
||
|
|
$onAttributes = $xPath->query('//@*[starts-with(name(), \'on\')]');
|
||
|
|
foreach ($onAttributes as $attr) {
|
||
|
|
/** @var \DOMAttr $attr*/
|
||
|
|
$attrName = $attr->nodeName;
|
||
|
|
$attr->parentNode->removeAttribute($attrName);
|
||
|
|
}
|
||
|
|
|
||
|
|
$html = '';
|
||
|
|
$topElems = $doc->documentElement->childNodes->item(0)->childNodes;
|
||
|
|
foreach ($topElems as $child) {
|
||
|
|
$html .= $doc->saveHTML($child);
|
||
|
|
}
|
||
|
|
|
||
|
|
return $html;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Removed all of the given DOMNodes.
|
||
|
|
*/
|
||
|
|
static protected function removeNodes(DOMNodeList $nodes): void
|
||
|
|
{
|
||
|
|
foreach ($nodes as $node) {
|
||
|
|
$node->parentNode->removeChild($node);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
}
|