<?php
/**
* Diaspora endpoint
*/
require_once('include/salmon.php');
require_once('include/certfns.php');
function receive_return($val) {
if($val >= 400)
$err = 'Error';
if($val >= 200 && $val < 300)
$err = 'OK';
logger('mod-diaspora returns ' . $val);
header($_SERVER["SERVER_PROTOCOL"] . ' ' . $val . ' ' . $err);
killme();
}
function get_diaspora_key($uri) {
$key = '';
logger('Fetching diaspora key for: ' . $uri);
$arr = lrdd($uri);
if(is_array($arr)) {
foreach($arr as $a) {
if($a['@attributes']['rel'] === 'diaspora-public-key') {
$key = base64_decode($a['@attributes']['href']);
}
}
}
else {
return '';
}
if($key)
return rsatopem($key);
return '';
}
function receive_post(&$a) {
if($a->argc != 3 || $a->argv[1] !== 'users')
receive_return(500);
$guid = $a->argv[2];
$r = q("SELECT * FROM `user` WHERE `guid` = '%s' LIMIT 1",
dbesc($guid)
);
if(! count($r))
salmon_return(500);
$importer = $r[0];
$xml = $_POST['xml'];
logger('mod-diaspora: new salmon ' . $xml, LOGGER_DATA);
if(! $xml)
receive_return(500);
$basedom = parse_xml_string($xml);
if($basedom)
logger('parsed dom');
$atom = $basedom->children(NAMESPACE_ATOM1);
logger('atom: ' . count($atom));
$encrypted_header = json_decode(base64_decode($atom->encrypted_header));
print_r($encrypted_header);
$encrypted_aes_key_bundle = base64_decode($encrypted_header->aes_key);
$ciphertext = base64_decode($encrypted_header->ciphertext);
logger('encrypted_aes: ' . print_r($encrypted_aes_key_bundle,true));
logger('ciphertext: ' . print_r($ciphertext,true));
$outer_key_bundle = '';
openssl_private_decrypt($encrypted_aes_key_bundle,$outer_key_bundle,$localprvkey);
logger('outer_bundle: ' . print_r($outer_key_bundle,true));
$j_outer_key_bundle = json_decode($outer_key_bundle);
$outer_iv = base64_decode($j_outer_key_bundle->iv);
$outer_key = base64_decode($j_outer_key_bundle->key);
$decrypted = mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $outer_key, $ciphertext, MCRYPT_MODE_CBC, $outer_iv);
$decrypted = pkcs5_unpad($decrypted);
logger('decrypted: ' . print_r($decrypted,true));
/**
* $decrypted now contains something like
*
* <decrypted_header>
* <iv>8e+G2+ET8l5BPuW0sVTnQw==</iv>
* <aes_key>UvSMb4puPeB14STkcDWq+4QE302Edu15oaprAQSkLKU=</aes_key>
* <author>
* <name>Ryan Hughes</name>
* <uri>acct:galaxor@diaspora.pirateship.org</uri>
* </author>
* </decrypted_header>
*/
$idom = parse_xml_string($decrypted,false);
$inner_iv = base64_decode($idom->iv);
$inner_aes_key = base64_decode($idom->aes_key);
logger('inner_iv: ' . $inner_iv);
$dom = $basedom->children(NAMESPACE_SALMON_ME);
if($dom)
logger('have dom');
logger('dom: ' . count($dom));
// figure out where in the DOM tree our data is hiding
if($dom->provenance->data)
$base = $dom->provenance;
elseif($dom->env->data)
$base = $dom->env;
elseif($dom->data)
$base = $dom;
if(! $base) {
logger('mod-diaspora: unable to locate salmon data in xml ');
dt_return(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);
logger('signature: ' . bin2hex($signature));
// 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);
// Add back the 60 char linefeeds
$lines = str_split($data,60);
$data = implode("\n",$lines);
// 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;
$signed_data = $data . (($data[-1] != "\n") ? "\n" : '') . '.' . base64url_encode($type) . "\n" . '.' . base64url_encode($encoding) . "\n" . '.' . base64url_encode($alg) . "\n";
logger('signed data: ' . $signed_data);
// decode the data
$data = base64url_decode($data);
// Now pull out the inner encrypted blob
$inner_encrypted = base64_decode($data);
$inner_decrypted =
$inner_decrypted = mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $inner_aes_key, $inner_encrypted, MCRYPT_MODE_CBC, $inner_iv);
$inner_decrypted = pkcs5_unpad($inner_decrypted);
logger('inner_decrypted: ' . $inner_decrypted);
if(! $author_link) {
logger('mod-diaspora: Could not retrieve author URI.');
receive_return(400);
}
// Once we have the author URI, go to the web and try to find their public key
// *** or look it up locally ***
logger('mod-diaspora: Fetching key for ' . $author_link );
// Get diaspora public key (pkcs#1) and convert to pkcs#8
$key = get_diaspora_key($author_link);
if(! $key) {
logger('mod-salmon: Could not retrieve author key.');
receive_return(400);
}
if (version_compare(PHP_VERSION, '5.3.0', '>=')) {
$verify = openssl_verify($signed_data,$signature,$key,'sha256');
}
else {
// FIXME
// fallback sha256 verify for PHP < 5.3
}
if(! $verify) {
logger('mod-diaspora: Message did not verify. Discarding.');
receive_return(400);
}
logger('mod-diaspora: 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.
$r = q("SELECT * FROM `contact` WHERE `network` = 'dspr' AND ( `url` = '%s' OR `alias` = '%s')
AND `uid` = %d LIMIT 1",
dbesc($author_link),
dbesc($author_link),
intval($importer['uid'])
);
if(! count($r)) {
logger('mod-diaspora: Author unknown to us.');
}
// is this a follower? Or have we ignored the person?
// If so we can not accept this post.
if((count($r)) && (($r[0]['readonly']) || ($r[0]['rel'] == REL_VIP) || ($r[0]['blocked']))) {
logger('mod-diaspora: Ignoring this author.');
receive_return(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);
// figure out what kind of diaspora message we have, and process accordingly.
receive_return(200);
}
