mod/pubsubhubbub.php

   1 <?php
   2 /**
   3  * @copyright Copyright (C) 2020, Friendica
   4  *
   5  * @license GNU AGPL version 3 or any later version
   6  *
   7  * This program is free software: you can redistribute it and/or modify
   8  * it under the terms of the GNU Affero General Public License as
   9  * published by the Free Software Foundation, either version 3 of the
  10  * License, or (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU Affero General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Affero General Public License
  18  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  19  *
  20  */
  21
  22 use Friendica\App;
  23 use Friendica\Core\Logger;
  24 use Friendica\Database\DBA;
  25 use Friendica\DI;
  26 use Friendica\Model\PushSubscriber;
  27 use Friendica\Util\Strings;
  28
  29 function post_var($name) {
  30         return !empty($_POST[$name]) ? Strings::escapeTags(trim($_POST[$name])) : '';
  31 }
  32
  33 function pubsubhubbub_init(App $a) {
  34         // PuSH subscription must be considered "public" so just block it
  35         // if public access isn't enabled.
  36         if (DI::config()->get('system', 'block_public')) {
  37                 throw new \Friendica\Network\HTTPException\ForbiddenException();
  38         }
  39
  40         // Subscription request from subscriber
  41         // https://pubsubhubbub.googlecode.com/git/pubsubhubbub-core-0.4.html#anchor4
  42         // Example from GNU Social:
  43         // [hub_mode] => subscribe
  44         // [hub_callback] => http://status.local/main/push/callback/1
  45         // [hub_verify] => sync
  46         // [hub_verify_token] => af11...
  47         // [hub_secret] => af11...
  48         // [hub_topic] => http://friendica.local/dfrn_poll/sazius
  49
  50         if ($_SERVER['REQUEST_METHOD'] === 'POST') {
  51                 $hub_mode = post_var('hub_mode');
  52                 $hub_callback = post_var('hub_callback');
  53                 $hub_verify_token = post_var('hub_verify_token');
  54                 $hub_secret = post_var('hub_secret');
  55                 $hub_topic = post_var('hub_topic');
  56
  57                 // check for valid hub_mode
  58                 if ($hub_mode === 'subscribe') {
  59                         $subscribe = 1;
  60                 } elseif ($hub_mode === 'unsubscribe') {
  61                         $subscribe = 0;
  62                 } else {
  63                         Logger::log("Invalid hub_mode=$hub_mode, ignoring.");
  64                         throw new \Friendica\Network\HTTPException\NotFoundException();
  65                 }
  66
  67                 Logger::log("$hub_mode request from " . $_SERVER['REMOTE_ADDR']);
  68
  69                 if ($a->argc > 1) {
  70                         // Normally the url should now contain the nick name as last part of the url
  71                         $nick = $a->argv[1];
  72                 } else {
  73                         // Get the nick name from the topic as a fallback
  74                         $nick = $hub_topic;
  75                 }
  76                 // Extract nick name and strip any .atom extension
  77                 $nick = basename($nick, '.atom');
  78
  79                 if (!$nick) {
  80                         Logger::log('Bad hub_topic=$hub_topic, ignoring.');
  81                         throw new \Friendica\Network\HTTPException\NotFoundException();
  82                 }
  83
  84                 // fetch user from database given the nickname
  85                 $condition = ['nickname' => $nick, 'account_expired' => false, 'account_removed' => false];
  86                 $owner = DBA::selectFirst('user', ['uid', 'nickname'], $condition);
  87                 if (!DBA::isResult($owner)) {
  88                         Logger::log('Local account not found: ' . $nick . ' - topic: ' . $hub_topic . ' - callback: ' . $hub_callback);
  89                         throw new \Friendica\Network\HTTPException\NotFoundException();
  90                 }
  91
  92                 // get corresponding row from contact table
  93                 $condition = ['uid' => $owner['uid'], 'blocked' => false,
  94                         'pending' => false, 'self' => true];
  95                 $contact = DBA::selectFirst('contact', ['poll'], $condition);
  96                 if (!DBA::isResult($contact)) {
  97                         Logger::log('Self contact for user ' . $owner['uid'] . ' not found.');
  98                         throw new \Friendica\Network\HTTPException\NotFoundException();
  99                 }
 100
 101                 // sanity check that topic URLs are the same
 102                 $hub_topic2 = str_replace('/feed/', '/dfrn_poll/', $hub_topic);
 103                 $self = DI::baseUrl() . '/api/statuses/user_timeline/' . $owner['nickname'] . '.atom';
 104
 105                 if (!Strings::compareLink($hub_topic, $contact['poll']) && !Strings::compareLink($hub_topic2, $contact['poll']) && !Strings::compareLink($hub_topic, $self)) {
 106                         Logger::log('Hub topic ' . $hub_topic . ' != ' . $contact['poll']);
 107                         throw new \Friendica\Network\HTTPException\NotFoundException();
 108                 }
 109
 110                 // do subscriber verification according to the PuSH protocol
 111                 $hub_challenge = Strings::getRandomHex(40);
 112
 113                 $params = http_build_query([
 114                         'hub.mode' => $subscribe == 1 ? 'subscribe' : 'unsubscribe',
 115                         'hub.topic' => $hub_topic,
 116                         'hub.challenge' => $hub_challenge,
 117                         'hub.verify_token' => $hub_verify_token,
 118
 119                         // lease time is hard coded to one week (in seconds)
 120                         // we don't actually enforce the lease time because GNU
 121                         // Social/StatusNet doesn't honour it (yet)
 122                         'hub.lease_seconds' => 604800,
 123                 ]);
 124
 125                 $hub_callback = rtrim($hub_callback, ' ?&#');
 126                 $separator = parse_url($hub_callback, PHP_URL_QUERY) === null ? '?' : '&';
 127
 128                 $fetchResult = DI::httpRequest()->fetchFull($hub_callback . $separator . $params);
 129                 $body = $fetchResult->getBody();
 130                 $ret = $fetchResult->getReturnCode();
 131
 132                 // give up if the HTTP return code wasn't a success (2xx)
 133                 if ($ret < 200 || $ret > 299) {
 134                         Logger::log("Subscriber verification for $hub_topic at $hub_callback returned $ret, ignoring.");
 135                         throw new \Friendica\Network\HTTPException\NotFoundException();
 136                 }
 137
 138                 // check that the correct hub_challenge code was echoed back
 139                 if (trim($body) !== $hub_challenge) {
 140                         Logger::log("Subscriber did not echo back hub.challenge, ignoring.");
 141                         Logger::log("\"$hub_challenge\" != \"".trim($body)."\"");
 142                         throw new \Friendica\Network\HTTPException\NotFoundException();
 143                 }
 144
 145                 PushSubscriber::renew($owner['uid'], $nick, $subscribe, $hub_callback, $hub_topic, $hub_secret);
 146
 147                 throw new \Friendica\Network\HTTPException\AcceptedException();
 148         }
 149         exit();
 150 }