]> git.mxchange.org Git - friendica.git/commitdiff
AP: Improved checks for incoming posts
authorMichael <heluecht@pirati.ca>
Sat, 12 Sep 2020 12:12:55 +0000 (12:12 +0000)
committerMichael <heluecht@pirati.ca>
Sat, 12 Sep 2020 12:12:55 +0000 (12:12 +0000)
src/Protocol/ActivityPub/Receiver.php

index c7d3ac67577656ed2bd22496855c13695af62304..8a3f76c5ea1789d0401e7ff6c1612468a1460a23 100644 (file)
@@ -33,7 +33,6 @@ use Friendica\Model\Item;
 use Friendica\Model\User;
 use Friendica\Protocol\Activity;
 use Friendica\Protocol\ActivityPub;
-use Friendica\Util\DateTimeFormat;
 use Friendica\Util\HTTPSignature;
 use Friendica\Util\JsonLD;
 use Friendica\Util\LDSignature;
@@ -59,6 +58,12 @@ class Receiver
        const CONTENT_TYPES = ['as:Note', 'as:Article', 'as:Video', 'as:Image', 'as:Event', 'as:Audio'];
        const ACTIVITY_TYPES = ['as:Like', 'as:Dislike', 'as:Accept', 'as:Reject', 'as:TentativeAccept'];
 
+       const TARGET_UNKNOWN = 0;
+       const TARGET_TO = 1;
+       const TARGET_CC = 2;
+       const TARGET_BCC = 3;
+       const TARGET_FOLLOWER = 4;
+
        /**
         * Checks if the web request is done for the AP protocol
         *
@@ -88,6 +93,7 @@ class Receiver
                        Logger::info('Valid HTTP signature', ['signer' => $http_signer]);
                }
 
+               $signer = [$http_signer];
                $activity = json_decode($body, true);
 
                if (empty($activity)) {
@@ -105,6 +111,8 @@ class Receiver
                        $ld_signer = LDSignature::getSigner($activity);
                        if (empty($ld_signer)) {
                                Logger::log('Invalid JSON-LD signature from ' . $actor, Logger::DEBUG);
+                       } elseif ($ld_signer != $http_signer) {
+                               $signer[] = $ld_signer;
                        }
                        if (!empty($ld_signer && ($actor == $http_signer))) {
                                Logger::log('The HTTP and the JSON-LD signature belong to ' . $ld_signer, Logger::DEBUG);
@@ -127,7 +135,7 @@ class Receiver
                        $trust_source = false;
                }
 
-               self::processActivity($ldactivity, $body, $uid, $trust_source, true);
+               self::processActivity($ldactivity, $body, $uid, $trust_source, true, $signer);
        }
 
        /**
@@ -186,9 +194,27 @@ class Receiver
         */
        public static function prepareObjectData($activity, $uid, $push, &$trust_source)
        {
+               $id = JsonLD::fetchElement($activity, '@id');
+               if (!empty($id) && !$trust_source) {
+                       $fetched_activity = ActivityPub::fetchContent($id, $uid ?? 0);
+                       if (!empty($fetched_activity)) {
+                               $object = JsonLD::compact($fetched_activity);
+                               $fetched_id = JsonLD::fetchElement($object, '@id');
+                               if ($fetched_id == $id) {
+                                       Logger::info('Activity had been fetched successfully', ['id' => $id]);
+                                       $trust_source = true;
+                                       $activity = $object;
+                               } else {
+                                       Logger::info('Activity id is not equal', ['id' => $id, 'fetched' => $fetched_id]);
+                               }
+                       } else {
+                               Logger::info('Activity could not been fetched', ['id' => $id]);
+                       }
+               }
+
                $actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
                if (empty($actor)) {
-                       Logger::log('Empty actor', Logger::DEBUG);
+                       Logger::info('Empty actor', ['activity' => $activity]);
                        return [];
                }
 
@@ -196,9 +222,11 @@ class Receiver
 
                // Fetch all receivers from to, cc, bto and bcc
                $receivers = self::getReceivers($activity, $actor);
+               $reception_type = [];
 
                // When it is a delivery to a personal inbox we add that user to the receivers
                if (!empty($uid)) {
+                       $reception_type[$uid] = self::TARGET_BCC;
                        $additional = ['uid:' . $uid => $uid];
                        $receivers = array_merge($receivers, $additional);
                } else {
@@ -222,11 +250,8 @@ class Receiver
 
                // Fetch the content only on activities where this matters
                if (in_array($type, ['as:Create', 'as:Update', 'as:Announce'])) {
-                       if ($type == 'as:Announce') {
-                               $trust_source = false;
-                       }
-
-                       $object_data = self::fetchObject($object_id, $activity['as:object'], $trust_source, $uid);
+                       // Always fetch on "Announce"
+                       $object_data = self::fetchObject($object_id, $activity['as:object'], $trust_source && ($type != 'as:Announce'), $uid);
                        if (empty($object_data)) {
                                Logger::log("Object data couldn't be processed", Logger::DEBUG);
                                return [];
@@ -246,9 +271,6 @@ class Receiver
                        } else {
                                $object_data['directmessage'] = JsonLD::fetchElement($activity, 'litepub:directMessage');
                        }
-
-                       // We had been able to retrieve the object data - so we can trust the source
-                       $trust_source = true;
                } elseif (in_array($type, array_merge(self::ACTIVITY_TYPES, ['as:Follow'])) && in_array($object_type, self::CONTENT_TYPES)) {
                        // Create a mostly empty array out of the activity data (instead of the object).
                        // This way we later don't have to check for the existence of ech individual array element.
@@ -288,6 +310,19 @@ class Receiver
                $object_data['actor'] = $actor;
                $object_data['item_receiver'] = $receivers;
                $object_data['receiver'] = array_merge($object_data['receiver'] ?? [], $receivers);
+               $object_data['reception_type'] = $reception_type;
+
+               $author = $object_data['author'] ?? $actor;
+               if (!empty($author) && !empty($object_data['id'])) {
+                       $author_host = parse_url($author, PHP_URL_HOST);
+                       $id_host = parse_url($object_data['id'], PHP_URL_HOST);
+                       if ($author_host == $id_host) {
+                               Logger::info('Valid hosts', ['type' => $type, 'host' => $id_host]);
+                       } else {
+                               Logger::notice('Differing hosts on author and id', ['type' => $type, 'author' => $author_host, 'id' => $id_host]);
+                               $trust_source = false;
+                       }
+               }
 
                Logger::log('Processing ' . $object_data['type'] . ' ' . $object_data['object_type'] . ' ' . $object_data['id'], Logger::DEBUG);
 
@@ -320,43 +355,49 @@ class Receiver
         * @param boolean $push         Message had been pushed to our system
         * @throws \Exception
         */
-       public static function processActivity($activity, $body = '', $uid = null, $trust_source = false, $push = false)
+       public static function processActivity($activity, string $body = '', int $uid = null, bool $trust_source = false, bool $push = false, array $signer = [])
        {
                $type = JsonLD::fetchElement($activity, '@type');
                if (!$type) {
-                       Logger::log('Empty type', Logger::DEBUG);
+                       Logger::info('Empty type', ['activity' => $activity]);
                        return;
                }
 
                if (!JsonLD::fetchElement($activity, 'as:object', '@id')) {
-                       Logger::log('Empty object', Logger::DEBUG);
+                       Logger::info('Empty object', ['activity' => $activity]);
                        return;
                }
 
-               if (!JsonLD::fetchElement($activity, 'as:actor', '@id')) {
-                       Logger::log('Empty actor', Logger::DEBUG);
+               $actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
+               if (empty($actor)) {
+                       Logger::info('Empty actor', ['activity' => $activity]);
                        return;
                }
 
-               // Don't trust the source if "actor" differs from "attributedTo". The content could be forged.
-               if ($trust_source && ($type == 'as:Create') && is_array($activity['as:object'])) {
-                       $actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
+               if (is_array($activity['as:object'])) {
                        $attributed_to = JsonLD::fetchElement($activity['as:object'], 'as:attributedTo', '@id');
-                       $trust_source = ($actor == $attributed_to);
-                       if (!$trust_source) {
-                               Logger::log('Not trusting actor: ' . $actor . '. It differs from attributedTo: ' . $attributed_to, Logger::DEBUG);
+               } else {
+                       $attributed_to = '';
+               }
+
+               // Test the provided signatures against the actor and "attributedTo"
+               if ($trust_source) {
+                       if (!empty($attributed_to) && !empty($actor)) {
+                               $trust_source = (in_array($actor, $signer) && in_array($attributed_to, $signer));
+                       } else {
+                               $trust_source = in_array($actor, $signer);
                        }
                }
 
                // $trust_source is called by reference and is set to true if the content was retrieved successfully
                $object_data = self::prepareObjectData($activity, $uid, $push, $trust_source);
                if (empty($object_data)) {
-                       Logger::log('No object data found', Logger::DEBUG);
+                       Logger::info('No object data found', ['activity' => $activity]);
                        return;
                }
 
                if (!$trust_source) {
-                       Logger::log('No trust for activity type "' . $type . '", so we quit now.', Logger::DEBUG);
+                       Logger::info('Activity trust could not be achieved.',  ['id' => $object_data['object_id'], 'type' => $type, 'signer' => $signer, 'actor' => $actor, 'attributedTo' => $attributed_to]);
                        return;
                }
 
@@ -517,7 +558,7 @@ class Receiver
 
                        Logger::log('Actor: ' . $actor . ' - Followers: ' . $followers, Logger::DEBUG);
                } else {
-                       Logger::log('Empty actor', Logger::DEBUG);
+                       Logger::info('Empty actor', ['activity' => $activity]);
                        $followers = '';
                }
 
@@ -775,18 +816,29 @@ class Receiver
                                $data = ActivityPub\Transmitter::createNote($item);
                                $object = JsonLD::compact($data);
                        }
+
+                       $id = JsonLD::fetchElement($object, '@id');
+                       if (empty($id)) {
+                               Logger::info('Empty id');
+                               return false;
+                       }
+       
+                       if ($id != $object_id) {
+                               Logger::info('Fetched id differs from provided id', ['provided' => $object_id, 'fetched' => $id]);
+                               return false;
+                       }
                } else {
                        Logger::log('Using original object for url ' . $object_id, Logger::DEBUG);
                }
 
                $type = JsonLD::fetchElement($object, '@type');
-
                if (empty($type)) {
-                       Logger::log('Empty type', Logger::DEBUG);
+                       Logger::info('Empty type');
                        return false;
                }
 
-               if (in_array($type, self::CONTENT_TYPES)) {
+               // We currently don't handle 'pt:CacheFile', but with this step we avoid logging
+               if (in_array($type, self::CONTENT_TYPES) || ($type == 'pt:CacheFile')) {
                        $object_data = self::processObject($object);
 
                        if (!empty($data)) {