SELinux - A 'gotcha' when templating /etc/selinux/config in jinja2 or 'how to lock yourself out'

I was writing an internal role that handles all things SELinux which can be included in playbooks just like any other role. However, I found out that when templating /etc/selinux/config using ansible and jinja2, you will have to use

 SELINUX={{ selinux_state }}

instead of

 SELINUX="{{ selinux_state }}"

since this might result in a system unable to log in or start any login manager due to not being able to load the correct context. There's the gotcha but how to fix it?

Reboot the machine into emergency mode.
--> Press 'e' in the grub menu
--> add 'rd.break' to the boot_cmdline like shown in the picture and press 'ctrl' + 'x' to boot

From here on out, remount the /sysroot directory as read-write

 switch_root:/# mount -o remount,rw /sysroot

chroot into your installation

 switch_root:/# chroot /sysroot

fix the /etc/selinux/config and relabel everything (just to ensure everything is going to be labeled correctly).

 sh-4.2# vi /etc/selinux/config  
 sh-4.2# touch /.autorelabel  
 sh-4.2# exit

Reboot into the machine into the normal target

 switch_root:/# reboot

The relabeling might take a while depending on the size of the filesystem.

Feel free to comment and / or suggest a topic.

Comments

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