diaspora salmon endpoint (decryption not yet provided)

1 files changed, 215 insertions, 0 deletions

diff --git a/mod/receive.php b/mod/receive.php
new file mode 100644
index 000000000..6e36109b3
--- /dev/null
+++ b/mod/receive.php
@@ -0,0 +1,215 @@
+<?php
+
+/**
+ * Diaspora endpoint
+ */
+
+
+
+require_once('include/salmon.php');
+require_once('library/simplepie/simplepie.inc');
+
+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 . ' ' . $err);
+	killme();
+
+}
+
+function receive_post(&$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);
+
+	// 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-diaspora: unable to locate salmon data in xml ');
+		receive_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);
+
+	// 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;
+
+	$signed_data = $data  . '.' . base64url_encode($type) . '.' . base64url_encode($encoding) . '.' . base64url_encode($alg);
+
+	// 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-diaspora: 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);
+    $feed->init();
+
+	logger('mod-diaspora: Feed parsed.');
+
+	if($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-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
+
+	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.');
+		receive_return(400);
+	}
+
+	// Setup RSA stuff to verify the signature
+
+	set_include_path(get_include_path() . PATH_SEPARATOR . 'library' . PATH_SEPARATOR . 'phpsec');
+
+	require_once('library/phpsec/Crypt/RSA.php');
+
+	$key_info = explode('.',$key);
+
+	$m = base64url_decode($key_info[1]);
+	$e = base64url_decode($key_info[2]);
+
+	logger('mod-salmon: key details: ' . print_r($key_info,true));
+
+    $rsa = new CRYPT_RSA();
+    $rsa->signatureMode = CRYPT_RSA_SIGNATURE_PKCS1;
+    $rsa->setHash('sha256');
+
+    $rsa->modulus = new Math_BigInteger($m, 256);
+    $rsa->k = strlen($rsa->modulus->toBytes());
+    $rsa->exponent = new Math_BigInteger($e, 256);
+
+    $verify = $rsa->verify($signed_data,$signature);
+
+	if(! $verify) {
+		logger('mod-diaspora: Message did not verify. Discarding.');
+		receive_return(400);
+	}
+
+	logger('mod-diaspora: Message verified.');
+
+	/* decrypt the sucker */
+	/*
+		// TODO
+	*/
+
+	/*
+	*
+	* 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)) ? $r[0] : null);
+
+	consume_feed($feedxml,$importer,$contact_rec,$hub);
+
+	receive_return(200);
+}
+
+
+
+