Outgoing posts are now signed

diff --git a/src/Protocol/ActivityPub.php b/src/Protocol/ActivityPub.php
index d952f4de8fc1220578a0220debba3cd420ac6024..6f5fdedc95dc551559bf6f0217dd583d4c25a5f2 100644 (file)
--- a/src/Protocol/ActivityPub.php
+++ b/src/Protocol/ActivityPub.php
@@ -20,6 +20,7 @@ use Friendica\Util\Crypto;
 use Friendica\Content\Text\BBCode;
 use Friendica\Content\Text\HTML;
 use Friendica\Util\JsonLD;
+use Friendica\Util\LDSignature;
 
 /**
  * @brief ActivityPub Protocol class
@@ -273,7 +274,10 @@ class ActivityPub
                $data = array_merge($data, ActivityPub::createPermissionBlockForItem($item));
 
                $data['object'] = self::createNote($item);
-               return $data;
+
+               $owner = User::getOwnerDataById($item['uid']);
+
+               return LDSignature::sign($data, $owner);
        }
 
        public static function createObjectFromItemID($item_id)
@@ -369,7 +373,9 @@ class ActivityPub
                        'to' => $profile['url']];
 
                logger('Sending activity ' . $activity . ' to ' . $target . ' for user ' . $uid, LOGGER_DEBUG);
-               return HTTPSignature::transmit($data,  $profile['inbox'], $uid);
+
+               $signed = LDSignature::sign($data, $owner);
+               return HTTPSignature::transmit($signed, $profile['inbox'], $uid);
        }
 
        public static function transmitContactAccept($target, $id, $uid)
@@ -387,7 +393,9 @@ class ActivityPub
                        'to' => $profile['url']];
 
                logger('Sending accept to ' . $target . ' for user ' . $uid . ' with id ' . $id, LOGGER_DEBUG);
-               return HTTPSignature::transmit($data,  $profile['inbox'], $uid);
+
+               $signed = LDSignature::sign($data, $owner);
+               return HTTPSignature::transmit($signed, $profile['inbox'], $uid);
        }
 
        public static function transmitContactReject($target, $id, $uid)
@@ -405,7 +413,9 @@ class ActivityPub
                        'to' => $profile['url']];
 
                logger('Sending reject to ' . $target . ' for user ' . $uid . ' with id ' . $id, LOGGER_DEBUG);
-               return HTTPSignature::transmit($data,  $profile['inbox'], $uid);
+
+               $signed = LDSignature::sign($data, $owner);
+               return HTTPSignature::transmit($signed, $profile['inbox'], $uid);
        }
 
        public static function transmitContactUndo($target, $uid)
@@ -425,7 +435,9 @@ class ActivityPub
                        'to' => $profile['url']];
 
                logger('Sending undo to ' . $target . ' for user ' . $uid . ' with id ' . $id, LOGGER_DEBUG);
-               return HTTPSignature::transmit($data,  $profile['inbox'], $uid);
+
+               $signed = LDSignature::sign($data, $owner);
+               return HTTPSignature::transmit($signed, $profile['inbox'], $uid);
        }
 
        /**

diff --git a/src/Util/LDSignature.php b/src/Util/LDSignature.php
new file mode 100644 (file)
index 0000000..7288b58
--- /dev/null
+++ b/src/Util/LDSignature.php
@@ -0,0 +1,92 @@
+<?php
+
+namespace Friendica\Util;
+
+use Friendica\Util\JsonLD;
+use Friendica\Util\DateTimeFormat;
+use Friendica\Protocol\ActivityPub;
+
+class LDSignature
+{
+       public static function isSigned($data)
+       {
+               return !empty($data['signature']);
+       }
+
+       public static function isVerified($data, $pubkey = null)
+       {
+               if (!self::isSigned($data)) {
+                       return false;
+               }
+
+               if (empty($pubkey)) {
+                       $actor = JsonLD::fetchElement($data, 'actor', 'id');
+                       if (empty($actor)) {
+                               return false;
+                       }
+
+                       $profile = ActivityPub::fetchprofile($actor);
+                       if (empty($profile['pubkey'])) {
+                               return false;
+                       }
+                       $pubkey = $profile['pubkey'];
+               }
+
+               $ohash = self::hash(self::signable_options($data['signature']));
+               $dhash = self::hash(self::signable_data($data));
+
+               $x = Crypto::rsaVerify($ohash . $dhash, base64_decode($data['signature']['signatureValue']), $pubkey);
+               logger('LD-verify: ' . intval($x));
+
+               return $x;
+       }
+
+       public static function sign($data, $owner)
+       {
+               $options = [
+                       'type' => 'RsaSignature2017',
+                       'nonce' => random_string(64),
+                       'creator' => $owner['url'] . '#main-key',
+                       'created' => DateTimeFormat::utcNow()
+               ];
+
+               $ohash = self::hash(self::signable_options($options));
+               $dhash = self::hash(self::signable_data($data));
+               $options['signatureValue'] = base64_encode(Crypto::rsaSign($ohash . $dhash, $owner['uprvkey']));
+
+               return array_merge($data, ['signature' => $options]);
+       }
+
+
+       private static function signable_data($data)
+       {
+               $newdata = [];
+               if (!empty($data)) {
+                       foreach ($data as $k => $v) {
+                               if (!in_array($k, ['signature'])) {
+                                       $newdata[$k] = $v;
+                               }
+                       }
+               }
+               return $newdata;
+       }
+
+
+       private static function signable_options($options)
+       {
+               $newopts = ['@context' => 'https://w3id.org/identity/v1'];
+               if (!empty($options)) {
+                       foreach ($options as $k => $v) {
+                               if (!in_array($k, ['type','id','signatureValue'])) {
+                                       $newopts[$k] = $v;
+                               }
+                       }
+               }
+               return $newopts;
+       }
+
+       private static function hash($obj)
+       {
+               return hash('sha256', JsonLD::normalize($obj));
+       }
+}