NixOS must initiate a session lock after a 10-minute period of inactivity for graphical user logon.

A session time-out lock is a temporary action taken when a user stops work and moves away from the immediate physical vicinity of the information system but does not log out because of the temporary nature of the absence. Rather than relying on the user to manually lock their operating system session prior to vacating the vicinity, operating systems need to be able to identify when a user's session has idled and take action to initiate the session lock.

The session lock is implemented at the point where session activity can be determined and/or controlled.

Verify NixOS initiates a session lock after a 10-minute period of inactivity for graphical user logon with the following command:

$ sudo gsettings get org.gnome.desktop.session idle-delay

uint32 600

$ grep "IdleAction" /etc/systemd/logind.conf

IdleAction = lock IdleActionSec = 600

$ systemctl --user status xautolock.service xautolock.service - xautolock service Loaded: loaded (/etc/systemd/user/xautolock.service; enabled; preset: ignored) Active: active (running) since Wed 2025-03-19 22:56:13 UTC; 6min ago Invocation: 836d5b6b79444c62aa3c5285e3c8d92e Main PID: 3233 (xautolock) Tasks: 1 (limit: 38062) Memory: 712K (peak: 2.4M) CPU: 75ms CGroup: /user.slice/user-1000.slice/user@1000.service/app.slice/xautolock.service +-3233 /nix/store/4chq53fkkiimbx1qzdbxxs44diiqgj54-xautolock-2.2-7-ga23dd5c/bin/xautolock -noclose -time 10 -locker "/nix/store/w9qcpyhjrxsqrps91wkz8r4mqvg9zrxc-systemd-256.10/bin/loginctl lock-session"

Mar 19 22:56:13 gcs-generic-5-3 systemd[3136]: Started xautolock service.

If "idle-delay" is set to "0" or a value greater than "600", this is a finding.

If "IdleAction" is not "lock" and "IdleActionSec" is not "600", this is a finding.

If the xautolock service is not present or the process line does not contain "-time 10", this is a finding.

Configure NixOS to initiate a session lock after a 10-minute period of inactivity for graphical user logon.

Update the NixOS config, typically stored either in /etc/nixos/configuration.nix or /etc/nixos/flake.nix:

programs.dconf.profiles.user.databases = with lib.gvariant; lib.mkBefore [ { settings."org/gnome/desktop/session".idle-delay = (mkUint32 600); locks = [ "org/gnome/desktop/session/idle-delay" ]; }]; services.logind.extraConfig = '' IdleAction = lock IdleActionSec = 600 ''; services.xserver = { displayManager.gdm.wayland = true; xautolock = { enable = true; time = 10; locker = "${lib.getExe' config.systemd.package "loginctl"} lock-session"; }; }; };

Rebuild and switch to the new NixOS configuration: $ sudo nixos-rebuild switch