HashService.php

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<?php
 
declare(strict_types=1);
 
/*
 * This file is part of the TYPO3 CMS project.
 *
 * It is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License, either version 2
 * of the License, or any later version.
 *
 * For the full copyright and license information, please read the
 * LICENSE.txt file that was distributed with this source code.
 *
 * The TYPO3 project - inspiring people to share!
 */
 
namespace ‪TYPO3\CMS\Extbase\Security\Cryptography;
 
use ‪TYPO3\CMS\Core\SingletonInterface;
use ‪TYPO3\CMS\Extbase\Security\Exception\InvalidArgumentForHashGenerationException;
use ‪TYPO3\CMS\Extbase\Security\Exception\InvalidHashException;
 
class ‪HashService implements ‪SingletonInterface
{
    public function ‪generateHmac(string $string): string
    {
        $encryptionKey = ‪$GLOBALS['TYPO3_CONF_VARS']['SYS']['encryptionKey'];
        if (!$encryptionKey) {
            throw new ‪InvalidArgumentForHashGenerationException('Encryption Key was empty!', 1255069597);
        }
        return hash_hmac('sha1', $string, $encryptionKey);
    }
 
    public function ‪appendHmac(string $string): string
    {
        $hmac = $this->‪generateHmac($string);
        return $string . $hmac;
    }
 
    public function ‪validateHmac(string $string, string $hmac): bool
    {
        return hash_equals($this->‪generateHmac($string), $hmac);
    }
 
    public function ‪validateAndStripHmac(string $string): string
    {
        if (strlen($string) < 40) {
            throw new ‪InvalidArgumentForHashGenerationException('A hashed string must contain at least 40 characters, the given string was only ' . strlen($string) . ' characters long.', 1320830276);
        }
        $stringWithoutHmac = substr($string, 0, -40);
        if ($this->‪validateHmac($stringWithoutHmac, substr($string, -40)) !== true) {
            throw new ‪InvalidHashException('The given string was not appended with a valid HMAC.', 1320830018);
        }
        return $stringWithoutHmac;
    }
}