Set shadow permissions

src/freedombone-utils-setup

     systemctl disable atd
 }
 
+function set_shadow_permissions {
+    chown root:root /etc/shadow
+    chmod 0000 /etc/shadow
+    chown root:root /etc/gshadow
+    chmod 0000 /etc/gshadow
+}
+
 function setup_firewall {
     function_check create_completion_file
     create_completion_file
     read_config_param "PROJECT_REPO"
     write_config_param "PROJECT_REPO" "$PROJECT_REPO"
 
+    function_check set_shadow_permissions
+    set_shadow_permissions
+
     function_check remove_bluetooth
     remove_bluetooth