Diaspora: Support for reading the /fetch/post/ functionality

diff --git a/include/diaspora.php b/include/diaspora.php
index 18206be8ed88bae758a1cf83a694bdc125851ff8..f2680b8d785ef0d55452d6810077fecf8e522765 100644 (file)
--- a/include/diaspora.php
+++ b/include/diaspora.php
@@ -100,6 +100,59 @@ class diaspora {
                return($signature);
        }
 
+       /**
+        * @brief verify the envelope and return the verified data
+        *
+        * @param string $envelope The magic envelope
+        *
+        * @return string verified data
+        */
+       private function verify_magic_envelope($envelope) {
+
+               $basedom = parse_xml_string($envelope, false);
+
+               if (!is_object($basedom)) {
+                       logger("Envelope is no XML file");
+                       return false;
+               }
+
+               $children = $basedom->children('http://salmon-protocol.org/ns/magic-env');
+
+               if (sizeof($children) == 0) {
+                       logger("XML has no children");
+                       return false;
+               }
+
+               $handle = "";
+
+               $data = base64url_decode($children->data);
+               $type = $children->data->attributes()->type[0];
+
+               $encoding = $children->encoding;
+
+               $alg = $children->alg;
+
+               $sig = base64url_decode($children->sig);
+               $key_id = $children->sig->attributes()->key_id[0];
+               if ($key_id != "")
+                       $handle = base64url_decode($key_id);
+
+               $b64url_data = base64url_encode($data);
+               $msg = str_replace(array("\n", "\r", " ", "\t"), array("", "", "", ""), $b64url_data);
+
+               $signable_data = $msg.".".base64url_encode($type).".".base64url_encode($encoding).".".base64url_encode($alg);
+
+               $key = self::key($handle);
+
+               $verify = rsa_verify($signable_data, $sig, $key);
+               if (!$verify) {
+                       logger('Message did not verify. Discarding.');
+                       return false;
+               }
+
+               return $data;
+       }
+
        /**
         * @brief: Decodes incoming Diaspora message
         *
@@ -233,7 +286,6 @@ class diaspora {
                return array('message' => (string)$inner_decrypted,
                                'author' => unxmlify($author_link),
                                'key' => (string)$key);
-
        }
 
 
@@ -816,11 +868,28 @@ class diaspora {
                if ($level > 5)
                        return false;
 
-               // This will work for Diaspora and newer Friendica servers
-               $source_url = $server."/p/".$guid.".xml";
-               $x = fetch_url($source_url);
-               if(!$x)
-                       return false;
+               // This will work for new Diaspora servers and Friendica servers from 3.5
+               $source_url = $server."/fetch/post/".$guid;
+               logger("Fetch post from ".$source_url, LOGGER_DEBUG);
+
+               $envelope = fetch_url($source_url);
+               if($envelope) {
+                       logger("Envelope was fetched.", LOGGER_DEBUG);
+                       $x = self::verify_magic_envelope($envelope);
+                       if (!$x) {
+                               logger("Envelope could not be verified.", LOGGER_DEBUG);
+                               return false;
+                       }
+                       logger("Envelope was verified.", LOGGER_DEBUG);
+               } else {
+                       // This will work for older Diaspora and Friendica servers
+                       $source_url = $server."/p/".$guid.".xml";
+                       logger("Fetch post from ".$source_url, LOGGER_DEBUG);
+
+                       $x = fetch_url($source_url);
+                       if(!$x)
+                               return false;
+               }
 
                $source_xml = parse_xml_string($x, false);
 
@@ -2265,7 +2334,7 @@ class diaspora {
         * @return string The envelope
         */
 
-       function build_magic_envelope($msg, $user) {
+       public static function build_magic_envelope($msg, $user) {
 
                $b64url_data = base64url_encode($msg);
                $data = str_replace(array("\n", "\r", " ", "\t"), array("", "", "", ""), $b64url_data);