friendica/src/Module/OStatus/Salmon.php

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<?php
/**
2023-01-01 14:36:24 +00:00
* @copyright Copyright (C) 2010-2023, 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\Module\OStatus;
use Friendica\App;
use Friendica\Core\L10n;
use Friendica\Core\Protocol;
use Friendica\Database\Database;
use Friendica\Model\GServer;
use Friendica\Model\Post;
use Friendica\Module\Response;
use Friendica\Protocol\ActivityNamespace;
use Friendica\Protocol\OStatus;
use Friendica\Util\Crypto;
use Friendica\Util\Network;
use Friendica\Network\HTTPException;
use Friendica\Protocol\Salmon as SalmonProtocol;
use Friendica\Util\Profiler;
use Friendica\Util\Strings;
use Psr\Log\LoggerInterface;
/**
* Technical endpoint for the Salmon protocol
*/
class Salmon extends \Friendica\BaseModule
{
/** @var Database */
private $database;
public function __construct(Database $database, L10n $l10n, App\BaseURL $baseUrl, App\Arguments $args, LoggerInterface $logger, Profiler $profiler, Response $response, array $server, array $parameters = [])
{
parent::__construct($l10n, $baseUrl, $args, $logger, $profiler, $response, $server, $parameters);
$this->database = $database;
}
/**
* @param array $request
* @return void
* @throws HTTPException\AcceptedException
* @throws HTTPException\BadRequestException
* @throws HTTPException\InternalServerErrorException
* @throws HTTPException\OKException
* @throws \ImagickException
*/
protected function rawContent(array $request = [])
{
$xml = Network::postdata();
$nickname = $this->parameters['nickname'] ?? '';
if (empty($nickname)) {
throw new HTTPException\BadRequestException('nickname parameter is mandatory');
}
$this->logger->debug('New Salmon', ['nickname' => $nickname, 'xml' => $xml]);
$importer = $this->database->selectFirst('user', [], ['nickname' => $nickname, 'account_expired' => false, 'account_removed' => false]);
if (!$this->database->isResult($importer)) {
throw new HTTPException\InternalServerErrorException();
}
// parse the xml
$dom = simplexml_load_string($xml, 'SimpleXMLElement', 0, ActivityNamespace::SALMON_ME);
$base = null;
// figure out where in the DOM tree our data is hiding
if (!empty($dom->provenance->data)) {
$base = $dom->provenance;
} elseif (!empty($dom->env->data)) {
$base = $dom->env;
} elseif (!empty($dom->data)) {
$base = $dom;
}
if (empty($base)) {
$this->logger->notice('unable to locate salmon data in xml');
throw new HTTPException\BadRequestException();
}
// Stash the signature away for now. We have to find their key or it won't be good for anything.
$signature = Strings::base64UrlDecode($base->sig);
// unpack the data
// strip whitespace so our data element will return to one big base64 blob
$data = str_replace([" ", "\t", "\r", "\n"], ["", "", "", ""], $base->data);
// stash away some other stuff for later
$type = $base->data[0]->attributes()->type[0];
$keyhash = $base->sig[0]->attributes()->keyhash[0] ?? '';
$encoding = $base->encoding;
$alg = $base->alg;
// Salmon magic signatures have evolved and there is no way of knowing ahead of time which
// flavour we have. We'll try and verify it regardless.
$stnet_signed_data = $data;
$signed_data = $data . '.' . Strings::base64UrlEncode($type) . '.' . Strings::base64UrlEncode($encoding) . '.' . Strings::base64UrlEncode($alg);
$compliant_format = str_replace('=', '', $signed_data);
// decode the data
$data = Strings::base64UrlDecode($data);
$author = OStatus::salmonAuthor($data, $importer);
$author_link = $author["author-link"];
if (!$author_link) {
$this->logger->notice('Could not retrieve author URI.');
throw new HTTPException\BadRequestException();
}
// Once we have the author URI, go to the web and try to find their public key
$this->logger->notice('Fetching key for ' . $author_link);
$key = SalmonProtocol::getKey($author_link, $keyhash);
if (!$key) {
$this->logger->notice('Could not retrieve author key.');
throw new HTTPException\BadRequestException();
}
$this->logger->info('Key details', ['info' => $key]);
$pubkey = SalmonProtocol::magicKeyToPem($key);
// We should have everything we need now. Let's see if it verifies.
// Try GNU Social format
$verify = Crypto::rsaVerify($signed_data, $signature, $pubkey);
$mode = 1;
if (!$verify) {
$this->logger->notice('Message did not verify using protocol. Trying compliant format.');
$verify = Crypto::rsaVerify($compliant_format, $signature, $pubkey);
$mode = 2;
}
if (!$verify) {
$this->logger->notice('Message did not verify using padding. Trying old statusnet format.');
$verify = Crypto::rsaVerify($stnet_signed_data, $signature, $pubkey);
$mode = 3;
}
if (!$verify) {
$this->logger->notice('Message did not verify. Discarding.');
throw new HTTPException\BadRequestException();
}
$this->logger->notice('Message verified with mode ' . $mode);
/*
*
* If we reached this point, the message is good. Now let's figure out if the author is allowed to send us stuff.
*
*/
$contact = $this->database->selectFirst(
'contact',
[],
[
"`network` IN (?, ?)
AND (`nurl` = ? OR `alias` = ? OR `alias` = ?)
AND `uid` = ?",
Protocol::OSTATUS, Protocol::DFRN,
Strings::normaliseLink($author_link), $author_link, Strings::normaliseLink($author_link),
$importer['uid']
]
);
if (!empty($contact['gsid'])) {
GServer::setProtocol($contact['gsid'], Post\DeliveryData::OSTATUS);
}
// Have we ignored the person?
// If so we can not accept this post.
if (!empty($contact['blocked'])) {
$this->logger->notice('Ignoring this author.');
throw new HTTPException\AcceptedException();
}
// Placeholder for hub discovery.
$hub = '';
$contact = $contact ?: [];
OStatus::import($data, $importer, $contact, $hub);
throw new HTTPException\OKException();
}
}