<?php // There is a lot of debug stuff in here because this is quite a // complicated process to try and sort out. require_once('include/salmon.php'); require_once('include/crypto.php'); require_once('library/simplepie/simplepie.inc'); function salmon_return($val) { if($val >= 400) $err = 'Error'; if($val >= 200 && $val < 300) $err = 'OK'; logger('mod-salmon returns ' . $val); header($_SERVER["SERVER_PROTOCOL"] . ' ' . $val . ' ' . $err); killme(); } function salmon_post(&$a) { $xml = file_get_contents('php://input'); logger('mod-salmon: new salmon ' . $xml, LOGGER_DATA); $nick = (($a->argc > 1) ? notags(trim($a->argv[1])) : ''); $mentions = (($a->argc > 2 && $a->argv[2] === 'mention') ? true : false); $r = q("SELECT * FROM `user` WHERE `nickname` = '%s' AND `account_expired` = 0 LIMIT 1", dbesc($nick) ); if(! count($r)) http_status_exit(500); $importer = $r[0]; // parse the xml $dom = simplexml_load_string($xml,'SimpleXMLElement',0,NAMESPACE_SALMON_ME); // figure out where in the DOM tree our data is hiding if($dom->provenance->data) $base = $dom->provenance; elseif($dom->env->data) $base = $dom->env; elseif($dom->data) $base = $dom; if(! $base) { logger('mod-salmon: unable to locate salmon data in xml '); http_status_exit(400); } // Stash the signature away for now. We have to find their key or it won't be good for anything. $signature = base64url_decode($base->sig); // unpack the data // strip whitespace so our data element will return to one big base64 blob $data = str_replace(array(" ","\t","\r","\n"),array("","","",""),$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 = $data . '.' . base64url_encode($type) . '.' . base64url_encode($encoding) . '.' . base64url_encode($alg); $compliant_format = str_replace('=','',$signed_data); // decode the data $data = base64url_decode($data); // Remove the xml declaration $data = preg_replace('/\<\?xml[^\?].*\?\>/','',$data); // Create a fake feed wrapper so simplepie doesn't choke $tpl = get_markup_template('fake_feed.tpl'); $base = substr($data,strpos($data,'<entry')); $feedxml = $tpl . $base . '</feed>'; logger('mod-salmon: Processed feed: ' . $feedxml); // Now parse it like a normal atom feed to scrape out the author URI $feed = new SimplePie(); $feed->set_raw_data($feedxml); $feed->enable_order_by_date(false); $feed->init(); logger('mod-salmon: Feed parsed.'); if($feed->get_item_quantity()) { foreach($feed->get_items() as $item) { $author = $item->get_author(); $author_link = unxmlify($author->get_link()); break; } } if(! $author_link) { logger('mod-salmon: Could not retrieve author URI.'); http_status_exit(400); } // Once we have the author URI, go to the web and try to find their public key logger('mod-salmon: Fetching key for ' . $author_link ); $key = get_salmon_key($author_link,$keyhash); if(! $key) { logger('mod-salmon: Could not retrieve author key.'); http_status_exit(400); } $key_info = explode('.',$key); $m = base64url_decode($key_info[1]); $e = base64url_decode($key_info[2]); logger('mod-salmon: key details: ' . print_r($key_info,true), LOGGER_DEBUG); $pubkey = metopem($m,$e); // We should have everything we need now. Let's see if it verifies. $verify = rsa_verify($compliant_format,$signature,$pubkey); if(! $verify) { logger('mod-salmon: message did not verify using protocol. Trying padding hack.'); $verify = rsa_verify($signed_data,$signature,$pubkey); } if(! $verify) { logger('mod-salmon: message did not verify using padding. Trying old statusnet hack.'); $verify = rsa_verify($stnet_signed_data,$signature,$pubkey); } if(! $verify) { logger('mod-salmon: Message did not verify. Discarding.'); http_status_exit(400); } logger('mod-salmon: Message verified.'); /* * * If we reached this point, the message is good. Now let's figure out if the author is allowed to send us stuff. * */ $r = q("SELECT * FROM `contact` WHERE `network` = 'stat' AND ( `url` = '%s' OR `alias` = '%s') AND `uid` = %d LIMIT 1", dbesc($author_link), dbesc($author_link), intval($importer['uid']) ); if(! count($r)) { logger('mod-salmon: Author unknown to us.'); } // is this a follower? Or have we ignored the person? // If so we can not accept this post. if((count($r)) && (($r[0]['readonly']) || ($r[0]['rel'] == CONTACT_IS_FOLLOWER) || ($r[0]['blocked']))) { logger('mod-salmon: Ignoring this author.'); http_status_exit(202); // NOTREACHED } require_once('include/items.php'); // Placeholder for hub discovery. We shouldn't find any hubs // since we supplied the fake feed header - and it doesn't have any. $hub = ''; /** * * anti-spam measure: consume_feed will accept a follow activity from * this person (and nothing else) if there is no existing contact record. * */ $contact_rec = ((count($r)) ? $r[0] : null); consume_feed($feedxml,$importer,$contact_rec,$hub); http_status_exit(200); }