Repost Non-root Shutdown Code

[Coral_Sea]

Can someone repost the code for enabling non-root users to shutdown or reboot without becoming su? The thread seems to have been dropped because it was created back in July. Thanks.

[Schotty]

Isnt it just changing the permissions on init or whatever reboot or shutdown symlink to? I am not on my linux box now (or near one -- at a remote location for work), but thats where I would start. I know RedHat 7.2 has the reboot and shutdown commands, which stock are set to be accessable to everyone. I changed them, but dont remember how at this moment (hangover, early for me.....)

[civ1492]

hmm you can power down with ctrl-alt-del if this is in /etc/inittab

ca::ctrlaltdel:/sbin/shutdown -a -t5 -rf now

the -a switch looks if the user who performs ctrl-alt-del has an entry in /etc/shutdown.allow if the name is there he is able to shutdown the system ..

its not the best solution but just something i found in the man pages ..

[Feztaa]

I'm sure this is a terribly way of doing it, but couldn't you just set the "halt" program (or whatever you use to shut down) as setuid? It's probably not the greatest idea because instead of having users be able to shut down, you'd end up giving (slightly restricted) root access to users who want to shut down...

[redhead]

hmm On RH 7.0 it worked, if you created a file /etc/sysconfig/console/shutdown whcih contained a list of users able to shutdown ie:
USER=root,user1,user2....

But dont know if it will work on any other dist.

[Coral_Sea]

I found a copy that I had saved before:

#include <unistd.h>
main() {
setuid(0);
execl("/sbin/halt", "halt", 0);
}

You have to compile this code like so (assuming the file is called shutdown.c):

gcc -o shutdown shutdown.c

then

chown root shutdown; chmod u+x shutdown

then

move it to non-root's path (e.g., /usr/local/bin).

[redhead]

I found a copy that I had saved before:

#include <unistd.h>
main() {
setuid(0);
execl("/sbin/halt", "halt", 0);
}

You have to compile this code like so (assuming the file is called shutdown.c):

gcc -o shutdown shutdown.c

then

chown root shutdown; chmod u+x shutdown

then

move it to non-root's path (e.g., /usr/local/bin).

You would still need to set the SUID bit on that program, It would be the same as Festaa suggested, to SUID halt or shutdown itself.

[Coral_Sea]

You would still need to set the SUID bit on that program, It would be the same as Festaa suggested, to SUID halt or shutdown itself.

I'm no expert in C programming, but I believe the line

setuid(0)

takes care of that worry.

[redhead]

ahhh I was reading it as chuid(0);... my bad..

You could also use sudo to prevent unauthorized users from shutting down your box.