friendica/src/Util/LDSignature.php

111 lines
2.5 KiB
PHP

<?php
namespace Friendica\Util;
use Friendica\Util\JsonLD;
use Friendica\Util\DateTimeFormat;
use Friendica\Protocol\ActivityPub;
/**
* @brief Implements JSON-LD signatures
*
* Ported from Osada: https://framagit.org/macgirvin/osada
*/
class LDSignature
{
public static function isSigned($data)
{
return !empty($data['signature']);
}
public static function getSigner($data)
{
if (!self::isSigned($data)) {
return false;
}
/*
$creator = $data['signature']['creator'];
$actor = JsonLD::fetchElement($data, 'actor', 'id');
$url = (strpos($creator, '#') ? substr($creator, 0, strpos($creator, '#')) : $creator);
$profile = ActivityPub::fetchprofile($url);
if (!empty($profile)) {
logger('Taking key from creator ' . $creator, LOGGER_DEBUG);
} elseif ($url != $actor) {
$profile = ActivityPub::fetchprofile($actor);
if (empty($profile)) {
return false;
}
logger('Taking key from actor ' . $actor, LOGGER_DEBUG);
}
*/
$actor = JsonLD::fetchElement($data, 'actor', 'id');
if (empty($actor)) {
return false;
}
$profile = ActivityPub::fetchprofile($actor);
if (empty($profile['pubkey'])) {
return false;
}
$pubkey = $profile['pubkey'];
$ohash = self::hash(self::signable_options($data['signature']));
$dhash = self::hash(self::signable_data($data));
$x = Crypto::rsaVerify($ohash . $dhash, base64_decode($data['signature']['signatureValue']), $pubkey);
logger('LD-verify: ' . intval($x));
if (empty($x)) {
return false;
} else {
return $actor;
}
}
public static function sign($data, $owner)
{
$options = [
'type' => 'RsaSignature2017',
'nonce' => random_string(64),
'creator' => $owner['url'] . '#main-key',
'created' => DateTimeFormat::utcNow(DateTimeFormat::ATOM)
];
$ohash = self::hash(self::signable_options($options));
$dhash = self::hash(self::signable_data($data));
$options['signatureValue'] = base64_encode(Crypto::rsaSign($ohash . $dhash, $owner['uprvkey']));
return array_merge($data, ['signature' => $options]);
}
private static function signable_data($data)
{
unset($data['signature']);
return $data;
}
private static function signable_options($options)
{
$newopts = ['@context' => 'https://w3id.org/identity/v1'];
if (!empty($options)) {
foreach ($options as $k => $v) {
if (!in_array($k, ['type', 'id', 'signatureValue'])) {
$newopts[$k] = $v;
}
}
}
return $newopts;
}
private static function hash($obj)
{
return hash('sha256', JsonLD::normalize($obj));
}
}