You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
 
 
 
 
 

55 lines
1.6 KiB

<?php
declare(strict_types=1);
/**
* SPDX-FileCopyrightText: 2022 Nextcloud GmbH and Nextcloud contributors
* SPDX-License-Identifier: AGPL-3.0-or-later
*/
namespace OCA\Talk\Service;
use OCA\Talk\Exceptions\UnauthorizedException;
class ChecksumVerificationService {
/**
* Check if the current request is coming from an allowed backend.
*
* The backend servers are sending custom headers "Talk-{{FEATURE}}-Random"
* containing at least 32 bytes random data, and the header
* "Talk-{{FEATURE}}-Checksum", which is the SHA256-HMAC of the random data
* and the body of the request, calculated with the shared secret from the
* configuration.
*
* @param string $random
* @param string $checksum
* @param string $secret
* @param string $data
* @return bool True if the request is from the backend and valid, false if not from SIP bridge
* @throws UnauthorizedException when the request tried to authenticate as backend but is not valid
*/
public function validateRequest(string $random, string $checksum, string $secret, string $data): bool {
if ($random === '' && $checksum === '') {
return false;
}
if (strlen($random) < 32) {
throw new UnauthorizedException('Invalid random provided');
}
if ($checksum === '') {
throw new UnauthorizedException('Invalid checksum provided');
}
if ($secret === '') {
throw new UnauthorizedException('No shared SIP secret provided');
}
$hash = hash_hmac('sha256', $random . $data, $secret);
if (hash_equals($hash, strtolower($checksum))) {
return true;
}
throw new UnauthorizedException('Invalid HMAC provided');
}
}