Signature check added

diff --git a/src/Module/Inbox.php b/src/Module/Inbox.php
index 0bc78b030cf3b54eccef48529bc7262c846a558e..63de5de12dd35143cf5dbe42b977407b0bdbcb63 100644 (file)
--- a/src/Module/Inbox.php
+++ b/src/Module/Inbox.php
@@ -5,10 +5,7 @@
 namespace Friendica\Module;
 
 use Friendica\BaseModule;
-use Friendica\Database\DBA;
-use Friendica\Model\Contact;
-use Friendica\Util\HTTPSignature;
-use Friendica\Util\Network;
+use Friendica\Protocol\ActivityPub;
 use Friendica\Core\System;
 
 /**
@@ -26,7 +23,13 @@ class Inbox extends BaseModule
                        System::httpExit(400);
                }
 
-               $tempfile = tempnam(get_temppath(), 'activitypub');
+               if (ActivityPub::verifySignature($postdata, $_SERVER)) {
+                       $filename = 'signed-activitypub';
+               } else {
+                       $filename = 'failed-activitypub';
+               }
+
+               $tempfile = tempnam(get_temppath(), filename);
                file_put_contents($tempfile, json_encode(['header' => $_SERVER, 'body' => $postdata]));
 
                System::httpExit(200);

diff --git a/src/Protocol/ActivityPub.php b/src/Protocol/ActivityPub.php
index 07989621f183854341cb45cdb96c9b2097ad5fd8..83aae72aa52c599d5cca7f54e690d992d49c1bd5 100644 (file)
--- a/src/Protocol/ActivityPub.php
+++ b/src/Protocol/ActivityPub.php
@@ -53,16 +53,11 @@ class ActivityPub
 
                $headers[] = 'Signature: keyId="' . $owner['url'] . '#main-key' . '",headers="(request-target) host date",signature="' . $signature . '"';
                $headers[] = 'Content-Type: application/activity+json';
-//print_r($headers);
-//die($signed_data);
-//$headers = [];
-//             $headers = HTTPSignature::createSig('', $headers, $owner['uprvkey'], $owner['url'] . '#main-key', false, false, 'sha256');
 
                Network::post($target, $content, $headers);
                $return_code = BaseObject::getApp()->get_curl_code();
-echo $return_code."\n";
-               print_r(BaseObject::getApp()->get_curl_headers());
-               print_r($headers);
+
+               echo $return_code."\n";
        }
 
        /**
@@ -226,6 +221,154 @@ echo $return_code."\n";
                return false;
        }
 
+       public static function verifySignature($content, $http_headers)
+       {
+               $object = json_decode($content, true);
+
+               if (empty($object)) {
+                       return false;
+               }
+
+               $actor = self::processElement($object, 'actor', 'id');
+
+               $headers = [];
+               $headers['(request-target)'] = strtolower($http_headers['REQUEST_METHOD']) . ' ' . $http_headers['REQUEST_URI'];
+
+               // First take every header
+               foreach ($http_headers as $k => $v) {
+                       $field = str_replace('_', '-', strtolower($k));
+                       $headers[$field] = $v;
+               }
+
+               // Now add every http header
+               foreach ($http_headers as $k => $v) {
+                       if (strpos($k, 'HTTP_') === 0) {
+                               $field = str_replace('_', '-', strtolower(substr($k, 5)));
+                               $headers[$field] = $v;
+                       }
+               }
+
+               $sig_block = ActivityPub::parseSigHeader($http_headers['HTTP_SIGNATURE']);
+
+               if (empty($sig_block) || empty($sig_block['headers']) || empty($sig_block['keyId'])) {
+                       return false;
+               }
+
+               $signed_data = '';
+               foreach ($sig_block['headers'] as $h) {
+                       if (array_key_exists($h, $headers)) {
+                               $signed_data .= $h . ': ' . $headers[$h] . "\n";
+                       }
+               }
+               $signed_data = rtrim($signed_data, "\n");
+
+               if (empty($signed_data)) {
+                       return false;
+               }
+
+               $algorithm = null;
+
+               if ($sig_block['algorithm'] === 'rsa-sha256') {
+                       $algorithm = 'sha256';
+               }
+
+               if ($sig_block['algorithm'] === 'rsa-sha512') {
+                       $algorithm = 'sha512';
+               }
+
+               if (empty($algorithm)) {
+                       return false;
+               }
+
+               $key = self::fetchKey($sig_block['keyId'], $actor);
+
+               if (empty($key)) {
+                       return false;
+               }
+
+               if (!Crypto::rsaVerify($signed_data, $sig_block['signature'], $key, $algorithm)) {
+                       return false;
+               }
+
+               // Check the digest if it was part of the signed data
+               if (in_array('digest', $sig_block['headers'])) {
+                       $digest = explode('=', $headers['digest'], 2);
+                       if ($digest[0] === 'SHA-256') {
+                               $hashalg = 'sha256';
+                       }
+                       if ($digest[0] === 'SHA-512') {
+                               $hashalg = 'sha512';
+                       }
+
+                       /// @todo addd all hashes from the rfc
+
+                       if (!empty($hashalg) && base64_encode(hash($hashalg, $content, true)) != $digest[1]) {
+                               return false;
+                       }
+               }
+
+               // Check the content-length if it was part of the signed data
+               if (in_array('content-length', $sig_block['headers'])) {
+                       if (strlen($content) != $headers['content-length']) {
+                               return false;
+                       }
+               }
+
+               return true;
+
+       }
+
+       private static function fetchKey($id, $actor)
+       {
+               $url = (strpos($id, '#') ? substr($id, 0, strpos($id, '#')) : $id);
+
+               $profile = self::fetchProfile($url);
+               if (!empty($profile)) {
+                       return $profile['pubkey'];
+               } elseif ($url != $actor) {
+                       $profile = self::fetchProfile($actor);
+                       if (!empty($profile)) {
+                               return $profile['pubkey'];
+                       }
+               }
+
+               return false;
+       }
+
+       /**
+        * @brief
+        *
+        * @param string $header
+        * @return array associate array with
+        *   - \e string \b keyID
+        *   - \e string \b algorithm
+        *   - \e array  \b headers
+        *   - \e string \b signature
+        */
+       private static function parseSigHeader($header)
+       {
+               $ret = [];
+               $matches = [];
+
+               if (preg_match('/keyId="(.*?)"/ism',$header,$matches)) {
+                       $ret['keyId'] = $matches[1];
+               }
+
+               if (preg_match('/algorithm="(.*?)"/ism',$header,$matches)) {
+                       $ret['algorithm'] = $matches[1];
+               }
+
+               if (preg_match('/headers="(.*?)"/ism',$header,$matches)) {
+                       $ret['headers'] = explode(' ', $matches[1]);
+               }
+
+               if (preg_match('/signature="(.*?)"/ism',$header,$matches)) {
+                       $ret['signature'] = base64_decode(preg_replace('/\s+/','',$matches[1]));
+               }
+
+               return $ret;
+       }
+
        /**
         * Fetches a profile from the given url
         *