Enable remote authentication with HTTP Signatures

src/App.php

@@ -12,7 +12,9 @@ use Friendica\Core\Config\Cache\ConfigCacheLoader;
 use Friendica\Core\Config\Cache\IConfigCache;
 use Friendica\Core\Config\Configuration;
 use Friendica\Database\DBA;
+use Friendica\Model\Profile;
 use Friendica\Network\HTTPException\InternalServerErrorException;
+use Friendica\Util\HTTPSignature;
 use Friendica\Util\Profiler;
 use Psr\Log\LoggerInterface;
 
@@ -1143,6 +1145,13 @@ class App
 			Core\Worker::executeIfIdle();
 		}
 
+		if ($this->getMode()->isNormal()) {
+			$requester = HTTPSignature::getSigner('', $_SERVER);
+			if (!empty($requester)) {
+				Profile::addVisitorCookieForHandle($requester);
+			}
+		}
+
 		// ZRL
 		if (!empty($_GET['zrl']) && $this->getMode()->isNormal()) {
 			$this->query_string = Model\Profile::stripZrls($this->query_string);

src/Model/Profile.php

@@ -1083,34 +1083,18 @@ class Profile
 	}
 
 	/**
-	 * OpenWebAuth authentication.
+	 * Set the visitor cookies (see remote_user()) for the given handle
 	 *
-	 * Ported from Hubzilla: https://framagit.org/hubzilla/core/blob/master/include/zid.php
-	 *
-	 * @param string $token
-	 * @throws \Friendica\Network\HTTPException\InternalServerErrorException
-	 * @throws \ImagickException
+	 * @param string $handle Visitor handle
+	 * @return array Visitor contact array
 	 */
-	public static function openWebAuthInit($token)
+	public static function addVisitorCookieForHandle($handle)
 	{
-		$a = \get_app();
-
-		// Clean old OpenWebAuthToken entries.
-		OpenWebAuthToken::purge('owt', '3 MINUTE');
-
-		// Check if the token we got is the same one
-		// we have stored in the database.
-		$visitor_handle = OpenWebAuthToken::getMeta('owt', 0, $token);
-
-		if($visitor_handle === false) {
-			return;
-		}
-
 		// Try to find the public contact entry of the visitor.
-		$cid = Contact::getIdForURL($visitor_handle);
-		if(!$cid) {
-			Logger::log('owt: unable to finger ' . $visitor_handle, Logger::DEBUG);
-			return;
+		$cid = Contact::getIdForURL($handle);
+		if (!$cid) {
+			Logger::log('unable to finger ' . $handle, Logger::DEBUG);
+			return [];
 		}
 
 		$visitor = DBA::selectFirst('contact', [], ['id' => $cid]);
@@ -1133,6 +1117,43 @@ class Profile
 
 			$_SESSION['remote'][] = ['cid' => $contact['id'], 'uid' => $contact['uid'], 'url' => $visitor['url']];
 		}
+
+		$a->contact = $visitor;
+
+		Logger::info('Authenticated visitor', ['url' => $visitor['url']]);
+
+		return $visitor;
+	}
+
+	/**
+	 * OpenWebAuth authentication.
+	 *
+	 * Ported from Hubzilla: https://framagit.org/hubzilla/core/blob/master/include/zid.php
+	 *
+	 * @param string $token
+	 * @throws \Friendica\Network\HTTPException\InternalServerErrorException
+	 * @throws \ImagickException
+	 */
+	public static function openWebAuthInit($token)
+	{
+		$a = \get_app();
+
+		// Clean old OpenWebAuthToken entries.
+		OpenWebAuthToken::purge('owt', '3 MINUTE');
+
+		// Check if the token we got is the same one
+		// we have stored in the database.
+		$visitor_handle = OpenWebAuthToken::getMeta('owt', 0, $token);
+
+		if ($visitor_handle === false) {
+			return;
+		}
+
+		$visitor = self::addVisitorCookieForHandle($visitor_handle);
+		if (empty($visitor)) {
+			return;
+		}
+
 		$arr = [
 			'visitor' => $visitor,
 			'url' => $a->query_string

src/Module/Photo.php

@@ -45,9 +45,6 @@ class Photo extends BaseModule
 			exit;
 		}
 
-		/// @todo Add Authentication to enable fetching of non public content
-		// $requester = HTTPSignature::getSigner('', $_SERVER);
-
 		$customsize = 0;
 		$photo = false;
 		switch($a->argc) {

src/Util/HTTPSignature.php

@@ -488,8 +488,10 @@ class HTTPSignature
 			return false;
 		}
 
+		$hasGoodSignedContent = false;
+
 		// Check the digest when it is part of the signed data
-		if (in_array('digest', $sig_block['headers'])) {
+		if (!empty($content) && in_array('digest', $sig_block['headers'])) {
 			$digest = explode('=', $headers['digest'], 2);
 			if ($digest[0] === 'SHA-256') {
 				$hashalg = 'sha256';
@@ -503,6 +505,8 @@ class HTTPSignature
 			if (!empty($hashalg) && base64_encode(hash($hashalg, $content, true)) != $digest[1]) {
 				return false;
 			}
+
+			$hasGoodSignedContent = true;
 		}
 
 		//  Check if the signed date field is in an acceptable range
@@ -512,6 +516,7 @@ class HTTPSignature
 				Logger::log("Header date '" . $headers['date'] . "' is with " . $diff . " seconds out of the 300 second frame. The signature is invalid.");
 				return false;
 			}
+			$hasGoodSignedContent = true;
 		}
 
 		// Check the content-length when it is part of the signed data
@@ -521,6 +526,12 @@ class HTTPSignature
 			}
 		}
 
+		// Ensure that the authentication had been done with some content
+		// Without this check someone could authenticate with fakeable data
+		if (!$hasGoodSignedContent) {
+			return false;
+		}
+
 		return $key['url'];
 	}