Friendica Communications Platform (please note that this is a clone of the repository at github, issues are handled there) https://friendi.ca
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<?php
/**
* @file mod/salmon.php
*/
use Friendica\App;
use Friendica\Core\PConfig;
use Friendica\Core\System;
use Friendica\Database\DBM;
use Friendica\Model\Contact;
use Friendica\Protocol\OStatus;
use Friendica\Protocol\Salmon;
use Friendica\Util\Crypto;
require_once 'include/items.php';
function salmon_post(App $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);
$r = q("SELECT * FROM `user` WHERE `nickname` = '%s' AND `account_expired` = 0 AND `account_removed` = 0 LIMIT 1",
dbesc($nick)
);
if (! DBM::is_result($r)) {
System::httpExit(500);
}
$importer = $r[0];
// parse the xml
$dom = simplexml_load_string($xml,'SimpleXMLElement',0,NAMESPACE_SALMON_ME);
$base = null;
// figure out where in the DOM tree our data is hiding
if($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 ');
System::httpExit(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
$data = str_replace([" ","\t","\r","\n"],["","","",""],$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 = $data . '.' . base64url_encode($type) . '.' . base64url_encode($encoding) . '.' . base64url_encode($alg);
$compliant_format = str_replace('=', '', $signed_data);
// decode the data
$data = base64url_decode($data);
$author = OStatus::salmonAuthor($data, $importer);
$author_link = $author["author-link"];
if(! $author_link) {
logger('mod-salmon: Could not retrieve author URI.');
System::httpExit(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);
$key = Salmon::getKey($author_link, $keyhash);
if(! $key) {
logger('mod-salmon: Could not retrieve author key.');
System::httpExit(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);
$pubkey = Crypto::meToPem($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('mod-salmon: message did not verify using protocol. Trying compliant format.');
$verify = Crypto::rsaVerify($compliant_format, $signature, $pubkey);
$mode = 2;
}
if (! $verify) {
logger('mod-salmon: message did not verify using padding. Trying old statusnet format.');
$verify = Crypto::rsaVerify($stnet_signed_data, $signature, $pubkey);
$mode = 3;
}
if (! $verify) {
logger('mod-salmon: Message did not verify. Discarding.');
System::httpExit(400);
}
logger('mod-salmon: Message verified with mode '.$mode);
/*
*
* If we reached this point, the message is good. Now let's figure out if the author is allowed to send us stuff.
*
*/
$r = q("SELECT * FROM `contact` WHERE `network` IN ('%s', '%s')
AND (`nurl` = '%s' OR `alias` = '%s' OR `alias` = '%s')
AND `uid` = %d LIMIT 1",
dbesc(NETWORK_OSTATUS),
dbesc(NETWORK_DFRN),
dbesc(normalise_link($author_link)),
dbesc($author_link),
dbesc(normalise_link($author_link)),
intval($importer['uid'])
);
if (! DBM::is_result($r)) {
logger('mod-salmon: Author unknown to us.');
if(PConfig::get($importer['uid'],'system','ostatus_autofriend')) {
$result = Contact::createFromProbe($importer['uid'], $author_link);
if($result['success']) {
$r = q("SELECT * FROM `contact` WHERE `network` = '%s' AND ( `url` = '%s' OR `alias` = '%s')
AND `uid` = %d LIMIT 1",
dbesc(NETWORK_OSTATUS),
dbesc($author_link),
dbesc($author_link),
intval($importer['uid'])
);
}
}
}
// Have we ignored the person?
// If so we can not accept this post.
//if((DBM::is_result($r)) && (($r[0]['readonly']) || ($r[0]['rel'] == CONTACT_IS_FOLLOWER) || ($r[0]['blocked']))) {
if (DBM::is_result($r) && $r[0]['blocked']) {
logger('mod-salmon: Ignoring this author.');
System::httpExit(202);
// NOTREACHED
}
// Placeholder for hub discovery.
$hub = '';
$contact_rec = ((DBM::is_result($r)) ? $r[0] : null);
OStatus::import($data, $importer, $contact_rec, $hub);
System::httpExit(200);
}