Il 24/01/20 23:00, Orion Poplawski ha scritto:
On 1/24/20 4:38 AM, Alessandro Baggi wrote:
Hi list,
I installed on my workstation C8.1 (1911) and performed a minimal install and then installed XFCE from EPEL.
I noticed a strange behaviour (don't know if this is the wanted default). If I try ,from normal user shell, to run command like "reboot" or "shutdown -h now" system will reboot/shutdown. This happens on tty console, on xfce terminal and ssh session.
My user is not in wheel and during install I have not enabled checkbox to give that user administration permission. I tried to create a new user with adduser but got the same problem.
To solve this I modified polkit login1 policy on /usr/share/polkit-1/actions/org.freedesktop.login1.policy setting <allow_active>no</allow_active> for statement that concern reboot and shutdown/poweroff.
Why on CentOS a normal user can shutdown the system without root privileges? I think that on any server normal user should not be able to shutdown the system without privileges.
This is a bug or a wanted default?
So, as you figured out from the polkit setting - "active" user's (i.e. with a "seat") have access to shut a machine down. Now to figure out who has a seat
- and you use "loginctl" to see that. For e.g. from my non-privileged user
logged into my CentOS 8.1 VM via ssh:
$ loginctl SESSION UID USER SEAT TTY 1 ##### user
it shows that I don't have a "seat" and so:
$ shutdown -h now Failed to set wall message, ignoring: Connection timed out Failed to power off system via logind: Interactive authentication required. Failed to open initctl fifo: Permission denied Failed to talk to init daemon.
as expected. Perhaps you can start tracking down with loginctl who has a seat and why.
Hi, thank you very much for your suggestion, loginctl did help me to understand this "problem". I tried to run loginctl on my VM logging in with ssh and I get this:
[testuser@localhost ~]$ loginctl SESSION UID USER SEAT TTY 3 1000 testuser
1 sessions listed.
and try to run reboot give me the expected behaviour. If I try from tty console I have a seat for testuser and can reboot the system.
I don't know what I done in the other test...
Thank you very much, I'm happy this is my mistake and not a centos bug.
Thank you to all user that helped me.