[fix] Added handling for multitenant parent

Author: pandafy

openwisp_users/multitenancy.py

@@ -57,15 +57,21 @@ def get_queryset(self, request):
         elif not self.multitenant_parent:
             return qs
         else:
-            qsarg = "{0}__organization__in".format(self.multitenant_parent)
-            return qs.filter(**{qsarg: user.organizations_managed})
+            qsarg = f"{self.multitenant_parent}__organization"
+            return qs.filter(
+                Q(**{f"{qsarg}__in": user.organizations_managed}) | Q(**{qsarg: None})
+            )
 
     def _has_org_permission(self, request, obj, perm_func):
         """
         Helper method to check object-level permissions for users
         associated with specific organizations.
         """
         perm = perm_func(request, obj)
+        if obj and self.multitenant_parent:
+            # In case of a multitenant parent, we need to check if the
+            # user has permission on the parent object.
+            obj = getattr(obj, self.multitenant_parent)
         if not request.user.is_superuser and obj and hasattr(obj, "organization_id"):
             perm = perm and (
                 obj.organization_id