friendica/src/Util/LDSignature.php

144 lines
3.6 KiB
PHP

<?php
/**
* @copyright Copyright (C) 2010-2024, the Friendica project
*
* @license GNU AGPL version 3 or any later version
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*
*/
namespace Friendica\Util;
use Friendica\Core\Logger;
use Friendica\Model\APContact;
/**
* Implements JSON-LD signatures
*
* Ported from Osada: https://framagit.org/macgirvin/osada
*/
class LDSignature
{
/**
* Checks if element 'signature' is found and not empty
*
* @param array $data
* @return bool
*/
public static function isSigned(array $data): bool
{
return !empty($data['signature']);
}
/**
* Returns actor (signer) from given data
*
* @param array $data
* @return mixed Returns actor or false on error
*/
public static function getSigner(array $data)
{
if (!self::isSigned($data)) {
return false;
}
$actor = JsonLD::fetchElement($data, 'actor', 'id');
if (empty($actor) || !is_string($actor)) {
return false;
}
$profile = APContact::getByURL($actor);
if (empty($profile['pubkey'])) {
return false;
}
$pubkey = $profile['pubkey'];
$ohash = self::hash(self::signableOptions($data['signature']));
$dhash = self::hash(self::signableData($data));
$x = Crypto::rsaVerify($ohash . $dhash, base64_decode($data['signature']['signatureValue']), $pubkey);
Logger::info('LD-verify', ['verified' => (int)$x, 'actor' => $profile['url']]);
if (empty($x)) {
return false;
} else {
return $actor;
}
}
/**
* Signs given data by owner's signature
*
* @param array $data Data to sign
* @param array $owner Owner information, like URL
* @return array Merged array of $data and signature
*/
public static function sign(array $data, array $owner): array
{
$options = [
'type' => 'RsaSignature2017',
'nonce' => Strings::getRandomHex(64),
'creator' => $owner['url'] . '#main-key',
'created' => DateTimeFormat::utcNow(DateTimeFormat::ATOM),
];
$ohash = self::hash(self::signableOptions($options));
$dhash = self::hash(self::signableData($data));
$options['signatureValue'] = base64_encode(Crypto::rsaSign($ohash . $dhash, $owner['uprvkey']));
return array_merge($data, ['signature' => $options]);
}
/**
* Removes element 'signature' from array
*
* @param array $data
* @return array With no element 'signature'
*/
private static function signableData(array $data): array
{
unset($data['signature']);
return $data;
}
/**
* Removes some elements and adds '@context' to it
*
* @param array $options
* @return array With some removed elements and added '@context' element
*/
private static function signableOptions(array $options): array
{
$newopts = ['@context' => 'https://w3id.org/identity/v1'];
unset($options['type']);
unset($options['id']);
unset($options['signatureValue']);
return array_merge($newopts, $options);
}
/**
* Hashes normalized object
*
* @param ??? $obj
* @return string SHA256 hash
*/
private static function hash($obj): string
{
return hash('sha256', JsonLD::normalize($obj));
}
}