Simplify check_perms logic

Also miscellaneous permission-related fixes

classes/permissions.class.php

    * @param string $MinClass Return false if the user's class level is below this.
    */
   public static function check_perms($PermissionName, $MinClass = 0) {
-
-    $OverrideClass = 1000;
-    $Override = G::$LoggedUser['EffectiveClass'] >= $OverrideClass;
-
-    return (
-      ($PermissionName == null
-        || (isset(G::$LoggedUser['Permissions'][$PermissionName])
-          && G::$LoggedUser['Permissions'][$PermissionName]))
-      && G::$LoggedUser['Permissions'][$PermissionName]
-      && (G::$LoggedUser['Class'] >= $MinClass
-        || G::$LoggedUser['EffectiveClass'] >= $MinClass
-        || $Override)
-    );
+    if (G::$LoggedUser['EffectiveClass'] >= 1000) return true; // Sysops can do anything
+    if (G::$LoggedUser['EffectiveClass'] < $MinClass) return false; // MinClass failure
+    return G::$LoggedUser['Permissions'][$PermissionName] ?? false; // Return actual permission
   }
 
   /**
         SELECT Level AS Class, `Values` AS Permissions, Secondary, PermittedForums
         FROM permissions
         WHERE ID = '$PermissionID'");
-      $Permission = G::$DB->next_record(MYSQLI_ASSOC, array('Permissions'));
+      $Permission = G::$DB->next_record(MYSQLI_ASSOC, ['Permissions']);
       G::$DB->set_query_id($QueryID);
       $Permission['Permissions'] = unserialize($Permission['Permissions']);
       G::$Cache->cache_value("perm_$PermissionID", $Permission, 2592000);
       $CustomPermissions = [];
     }
 
-    $MaxCollages = $Permissions['Permissions']['MaxCollages'] + $BonusCollages;
+    $MaxCollages = ($Permissions['Permissions']['MaxCollages'] ?? 0) + $BonusCollages;
     if (isset($CustomPermissions['MaxCollages'])) {
       $MaxCollages += $CustomPermissions['MaxCollages'];
       unset($CustomPermissions['MaxCollages']);
   }
 
   public static function is_mod($UserID) {
-    $Permissions = self::get_permissions_for_user($UserID);
-    return isset($Permissions['users_mod']) && $Permissions['users_mod'];
+    return self::get_permissions_for_user($UserID)['users_mod'] ?? false;
   }
 }
 ?>

classes/script_start.php

         'SessionID' => $SessionID,
         'Browser' => $Browser,
         'OperatingSystem' => $OperatingSystem,
-        'IP' => ((apcu_exists('DBKEY')) ? DBCrypt::encrypt($_SERVER['REMOTE_ADDR']) : $UserSessions[$SessionID]['IP']),
+        'IP' => (apcu_exists('DBKEY') ? DBCrypt::encrypt($_SERVER['REMOTE_ADDR']) : $UserSessions[$SessionID]['IP']),
         'LastUpdate' => sqltime() );
     $Cache->insert_front($SessionID, $UsersSessionCache);
     $Cache->commit_transaction(0);

sections/userhistory/passkey_history.php

   error(403);
 }
 
-View::show_header("PassKey history for $Username");
+View::show_header("Passkey history for $Username");
 
 $DB->query("
   SELECT