friendica-github/mod/salmon.php
2021-10-19 22:25:49 +02:00

184 lines
5.5 KiB
PHP

<?php
/**
* @copyright Copyright (C) 2010-2021, 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/>.
*
*/
use Friendica\App;
use Friendica\Core\Logger;
use Friendica\Core\Protocol;
use Friendica\Database\DBA;
use Friendica\DI;
use Friendica\Model\Contact;
use Friendica\Model\GServer;
use Friendica\Model\Post;
use Friendica\Protocol\ActivityNamespace;
use Friendica\Protocol\OStatus;
use Friendica\Protocol\Salmon;
use Friendica\Util\Crypto;
use Friendica\Util\Network;
use Friendica\Util\Strings;
function salmon_post(App $a, $xml = '') {
if (empty($xml)) {
$xml = Network::postdata();
}
Logger::debug('new salmon ' . $xml);
$nick = ((DI::args()->getArgc() > 1) ? Strings::escapeTags(trim(DI::args()->getArgv()[1])) : '');
$importer = DBA::selectFirst('user', [], ['nickname' => $nick, 'account_expired' => false, 'account_removed' => false]);
if (! DBA::isResult($importer)) {
throw new \Friendica\Network\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)) {
Logger::notice('unable to locate salmon data in xml');
throw new \Friendica\Network\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) {
Logger::notice('Could not retrieve author URI.');
throw new \Friendica\Network\HTTPException\BadRequestException();
}
// Once we have the author URI, go to the web and try to find their public key
Logger::notice('Fetching key for ' . $author_link);
$key = Salmon::getKey($author_link, $keyhash);
if(! $key) {
Logger::notice('Could not retrieve author key.');
throw new \Friendica\Network\HTTPException\BadRequestException();
}
$key_info = explode('.',$key);
$m = Strings::base64UrlDecode($key_info[1]);
$e = Strings::base64UrlDecode($key_info[2]);
Logger::info('key details', ['info' => $key_info]);
$pubkey = Crypto::meToPem($m, $e);
// 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) {
Logger::notice('message did not verify using protocol. Trying compliant format.');
$verify = Crypto::rsaVerify($compliant_format, $signature, $pubkey);
$mode = 2;
}
if (! $verify) {
Logger::notice('message did not verify using padding. Trying old statusnet format.');
$verify = Crypto::rsaVerify($stnet_signed_data, $signature, $pubkey);
$mode = 3;
}
if (! $verify) {
Logger::notice('Message did not verify. Discarding.');
throw new \Friendica\Network\HTTPException\BadRequestException();
}
Logger::notice('Message verified with mode '.$mode);
/*
*
* If we reached this point, the message is good. Now let's figure out if the author is allowed to send us stuff.
*
*/
$contact = DBA::selectFirst('contact', [], ["`network` IN (?, ?) AND (`nurl` = ? OR `alias` = ? OR `alias` = ?) AND `uid` = ?",
Protocol::OSTATUS, Protocol::DFRN, Strings::normaliseLink($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'])) {
Logger::notice('Ignoring this author.');
throw new \Friendica\Network\HTTPException\AcceptedException();
}
// Placeholder for hub discovery.
$hub = '';
$contact = $contact ?: [];
OStatus::import($data, $importer, $contact, $hub);
throw new \Friendica\Network\HTTPException\OKException();
}