<?php /** * @copyright Copyright (C) 2010-2022, 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\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 = 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(); }