Disable reboot when ctrl-alt-del is pressed
This document (7023999) is provided subject to the disclaimer at the end of this document.
ctrl-alt-del.target systemd starts this target whenever Control+Alt+Del is pressed on the console. Usually, this should be aliased (symlinked) to reboot.target.
In GNOME, we see that ctrl-alt-delete points to a logout plugin:
gsettings list-recursively org.gnome.settings-daemon.plugins.media-keys org.gnome.settings-daemon.plugins.media-keys logout '<Control><Alt>Delete'
To prevent systemd reacting on on ctrl-alt-del key combination on a TTY, mask ctrl-alt-del.target unit (this in fact creates symlink to /dev/null):
systemctl mask ctrl-alt-del.target
Now check to ensure the symlink has been set/updated as expected:
ls -l /etc/systemd/system/ctrl-alt-del.target lrwxrwxrwx 1 root root 9 Mar 23 14:51 /etc/systemd/system/ctrl-alt-del.target -> /dev/null
Ctrl-alt-del reboot has now been disabled. Test ctrl-alt-del to verify.
NOTE: systemd has a feature to still perform an action if ctrl-alt-delete key combination is pressed on a condition that user presses the keys more than 7 times in 2 seconds. See man systemd-system.conf(5):
CtrlAltDelBurstAction= Defines what action will be performed if user presses Ctrl-Alt-Delete more than 7 times in 2s. Can be set to "reboot-force", "poweroff-force", "reboot-immediate", "poweroff-immediate" or disabled with "none". Defaults to "reboot-force".
To prevent systemd from reacting on ctrl-alt-delete burst, do:
1. set 'CtrlAltDelBurstAction=none' in /etc/systemd/system.conf
2. reload systemd configuration with: systemctl daemon-reload
To change this behavior to no longer reboot in GNOME on ctrl-alt-del, change the value for the logout key to something else. In the following example, it will be changed to ctrl-alt-shift-del requiring shift to be pressed as well.
Run the following logged into gnome for the user you wish to change:
gsettings set org.gnome.settings-daemon.plugins.media-keys logout '<Control><Alt><Shift>Delete'
Now test ctrl-alt-del.
This will need to be run for each existing or new user which you wish to change the ctrl-alt-del behavior for.
This is not ideal, as a disadvantage of this is that this can be overwritten by the user too..)
When it is desirable to disable the ctrl-alt-del behavior globally and for all users, follow the following procedure :
Create /etc/dconf/profile/user file with the following content :
Create /etc/dconf/db/local.d/01-local file with the following content :
Lock the logout property by creating /etc/dconf/db/local.d/locks/media-keys file with the following content :
Next save and update the dconf database :
This procedure has been detailed in TID 000019048 - Define global customer keybindings for shutdown
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- Document ID:7023999
- Creation Date: 11-Jul-2019
- Modified Date:30-Mar-2023
- SUSE Linux Enterprise Desktop
- SUSE Linux Enterprise Server
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