Add checks for $a->user existence

- Variable can be empty/null in many cases

src/App/Page.php

@@ -276,7 +276,7 @@ class Page implements ArrayAccess
 		// If you're just visiting, let javascript take you home
 		if (!empty($_SESSION['visitor_home'])) {
 			$homebase = $_SESSION['visitor_home'];
-		} elseif (local_user()) {
+		} elseif (!empty($app->user['nickname'])) {
 			$homebase = 'profile/' . $app->user['nickname'];
 		}
 

src/BaseModule.php

@@ -96,11 +96,11 @@ abstract class BaseModule
 	 * Functions used to protect against Cross-Site Request Forgery
 	 * The security token has to base on at least one value that an attacker can't know - here it's the session ID and the private key.
 	 * In this implementation, a security token is reusable (if the user submits a form, goes back and resubmits the form, maybe with small changes;
-	 * or if the security token is used for ajax-calls that happen several times), but only valid for a certain amout of time (3hours).
+	 * or if the security token is used for ajax-calls that happen several times), but only valid for a certain amount of time (3hours).
-	 * The "typename" seperates the security tokens of different types of forms. This could be relevant in the following case:
+	 * The "typename" separates the security tokens of different types of forms. This could be relevant in the following case:
-	 *    A security token is used to protekt a link from CSRF (e.g. the "delete this profile"-link).
+	 *    A security token is used to protect a link from CSRF (e.g. the "delete this profile"-link).
 	 *    If the new page contains by any chance external elements, then the used security token is exposed by the referrer.
-	 *    Actually, important actions should not be triggered by Links / GET-Requests at all, but somethimes they still are,
+	 *    Actually, important actions should not be triggered by Links / GET-Requests at all, but sometimes they still are,
 	 *    so this mechanism brings in some damage control (the attacker would be able to forge a request to a form of this type, but not to forms of other types).
 	 */
 	public static function getFormSecurityToken($typename = '')
@@ -108,7 +108,7 @@ abstract class BaseModule
 		$a = DI::app();
 
 		$timestamp = time();
-		$sec_hash = hash('whirlpool', $a->user['guid'] . $a->user['prvkey'] . session_id() . $timestamp . $typename);
+		$sec_hash = hash('whirlpool', ($a->user['guid'] ?? '') . ($a->user['prvkey'] ?? '') . session_id() . $timestamp . $typename);
 
 		return $timestamp . '.' . $sec_hash;
 	}

view/theme/frio/theme.php

@@ -224,7 +224,7 @@ function frio_remote_nav($a, &$nav)
 
 	// since $userinfo isn't available for the hook we write it to the nav array
 	// this isn't optimal because the contact query will be done now twice
-	if (local_user()) {
+	if (local_user() && !empty($a->user['uid'])) {
 		// empty the server url for local user because we won't need it
 		$server_url = '';
 		// user info

view/theme/vier/theme.php

@@ -27,7 +27,7 @@ function vier_init(App $a)
 
 	Renderer::setActiveTemplateEngine('smarty3');
 
-	if (!empty($a->argv[0]) && ($a->argv[0] . ($a->argv[1] ?? '')) === ('profile' . $a->user['nickname']) || $a->argv[0] === 'network' && local_user()) {
+	if (!empty($a->argv[0]) && ($a->argv[0] . ($a->argv[1] ?? '')) === ('profile' . ($a->user['nickname'] ?? '')) || $a->argv[0] === 'network' && local_user()) {
 		vier_community_info();
 
 		DI::page()['htmlhead'] .= "<link rel='stylesheet' type='text/css' href='view/theme/vier/wide.css' media='screen and (min-width: 1300px)'/>\n";