64 lines
1.7 KiB
PHP
64 lines
1.7 KiB
PHP
<?php
|
|
|
|
namespace BookStack\Util;
|
|
|
|
use DOMDocument;
|
|
use DOMElement;
|
|
use DOMNodeList;
|
|
use DOMXPath;
|
|
|
|
class HtmlNonceApplicator
|
|
{
|
|
protected static $placeholder = '[CSP_NONCE_VALUE]';
|
|
|
|
/**
|
|
* Prepare the given HTML content with nonce attributes including a placeholder
|
|
* value which we can target later.
|
|
*/
|
|
public static function prepare(string $html): string
|
|
{
|
|
if (empty($html)) {
|
|
return $html;
|
|
}
|
|
|
|
$html = '<body>' . $html . '</body>';
|
|
libxml_use_internal_errors(true);
|
|
$doc = new DOMDocument();
|
|
$doc->loadHTML(mb_convert_encoding($html, 'HTML-ENTITIES', 'UTF-8'));
|
|
$xPath = new DOMXPath($doc);
|
|
|
|
// Apply to scripts
|
|
$scriptElems = $xPath->query('//script');
|
|
static::addNonceAttributes($scriptElems, static::$placeholder);
|
|
|
|
// Apply to styles
|
|
$styleElems = $xPath->query('//style');
|
|
static::addNonceAttributes($styleElems, static::$placeholder);
|
|
|
|
$returnHtml = '';
|
|
$topElems = $doc->documentElement->childNodes->item(0)->childNodes;
|
|
foreach ($topElems as $child) {
|
|
$returnHtml .= $doc->saveHTML($child);
|
|
}
|
|
|
|
return $returnHtml;
|
|
}
|
|
|
|
/**
|
|
* Apply the give nonce value to the given prepared HTML.
|
|
*/
|
|
public static function apply(string $html, string $nonce): string
|
|
{
|
|
return str_replace(static::$placeholder, $nonce, $html);
|
|
}
|
|
|
|
protected static function addNonceAttributes(DOMNodeList $nodes, string $attrValue): void
|
|
{
|
|
/** @var DOMElement $node */
|
|
foreach ($nodes as $node) {
|
|
$node->setAttribute('nonce', $attrValue);
|
|
}
|
|
}
|
|
|
|
}
|