[SOLVED] force a reboot as a regular user

ag33k · 01-04-2017, 07:59 PM

1) I want to be able to run this as a regular user,

Code:

#!/bin/bash

echo 1 > /proc/sys/kernel/sysrq
echo b > /proc/sysrq-trigger

If I run a script with that it won't work!
Because I'm not able to run anything like that as regular user!

For now it works on root .bashrc like this,

Code:

function  reboot_force() {

    echo 1 > /proc/sys/kernel/sysrq
    echo b > /proc/sysrq-trigger

}

I have this on my slackwarearm on RPi3 (and also in a laptop) and it would be nice using this as a regular user. Because my Pi sometimes hangs on due to firefox.

2) Being able to do this as regular user have any security concerns?

EDIT: I post it here because is not only arm related!

syg00 · 01-04-2017, 08:55 PM

Try it as

Code:

echo 1 | sudo tee /proc/sys/kernel/sysrq
echo b | sudo tee /proc/sysrq-trigger

bassmadrigal · 01-04-2017, 09:24 PM

I'm not sure if you can do that as a normal user without using sudo. Whenever you give a user the ability to run commands as root, there's always security concerns, but there's ways to minimize those concerns by limiting what your user can run with sudo. The best way to do that would be to create a script that is only writeable by root with the commands you need to run, then give your user the ability to only execute that script using sudo.

You could create a script like /usr/bin/force-reboot containing your commands:

Code:

#!/bin/bash

echo 1 > /proc/sys/kernel/sysrq
echo b > /proc/sysrq-trigger

Then you would need to run visudo to allow your user to run sudo force-reboot with root permissions. By default, it will use the vi editor, but if you don't like it, you can override it with a different editor using EDITOR=nano visudo (replacing nano with a different editor if you don't like nano).

Then you would just add the below in that file (it doesn't need to be in any specific place). You can either choose to have to enter your user's password or no password (obviously requiring a password is a little more secure).

Code:

ag33k ALL=NOPASSWD: /usr/bin/force-reboot

If you want to restrict it to only work when your on your local machine (so it wouldn't work when you're ssh'ed in), you can change the "ALL" to localhost, and if you want to type your password, you would change NOPASSWD to PASSWD.

allend · 01-05-2017, 01:33 AM

The quick and dirty solution to a forced reboot in default Slackware is in /etc/inittab

Code:

# What to do at the "Three Finger Salute".
ca::ctrlaltdel:/sbin/shutdown -t5 -r now

pan64 · 01-05-2017, 01:53 AM

yes, why don't you execute:

Code:

sudo /sbin/shutdown -r now
#or
sudo /sbin/reboot -f
#long time ago I used to force reboot by:
sudo init 6

but I would say you only need to restart firefox (probably)

frankbell · 01-05-2017, 06:22 PM

Please note that Slackware does not configure the sudoers file by default. The fascination with sudo is very much a *buntu thing.

If you want to use sudo on Slackware, you will first have to edit sudoers, as root, using the visudo command.

jamison20000e · 01-05-2017, 06:28 PM

Pi, unplug it?

ag33k · 01-07-2017, 09:32 PM

Quote:

Originally Posted by bassmadrigal

I'm not sure if you can do that as a normal user without using sudo. Whenever you give a user the ability to run commands as root, there's always security concerns, but there's ways to minimize those concerns by limiting what your user can run with sudo. The best way to do that would be to create a script that is only writeable by root with the commands you need to run, then give your user the ability to only execute that script using sudo.

You could create a script like /usr/bin/force-reboot containing your commands:

Code:

#!/bin/bash

echo 1 > /proc/sys/kernel/sysrq
echo b > /proc/sysrq-trigger

Then you would need to run visudo to allow your user to run sudo force-reboot with root permissions. By default, it will use the vi editor, but if you don't like it, you can override it with a different editor using EDITOR=nano visudo (replacing nano with a different editor if you don't like nano).

Then you would just add the below in that file (it doesn't need to be in any specific place). You can either choose to have to enter your user's password or no password (obviously requiring a password is a little more secure).

Code:

ag33k ALL=NOPASSWD: /usr/bin/force-reboot

If you want to restrict it to only work when your on your local machine (so it wouldn't work when you're ssh'ed in), you can change the "ALL" to localhost, and if you want to type your password, you would change NOPASSWD to PASSWD.

Thanks

Code:

# ls -lisah /usr/bin/force-reboot  
1500248 4.0K -rwxr-xr-x 1 pi pi 126 Jan  5 01:14 /usr/bin/force-reboot

force-reboot

Code:

#!/bin/bash

echo 1 > /proc/sys/kernel/sysrq
echo b > /proc/sysrq-trigger

/etc/sudoers

Code:

pi ALL=NOPASSWD: /usr/bin/force-reboot

Output:

Code:

$ force-reboot 
/usr/bin/force-reboot: line 5: /proc/sys/kernel/sysrq: Permission denied
/usr/bin/force-reboot: line 6: /proc/sysrq-trigger: Permission denied

Only works as root!

bassmadrigal · 01-07-2017, 10:19 PM

Quote:

Originally Posted by ag33k

Output:

Code:

$ force-reboot 
/usr/bin/force-reboot: line 5: /proc/sys/kernel/sysrq: Permission denied
/usr/bin/force-reboot: line 6: /proc/sysrq-trigger: Permission denied

Only works as root!

You still need to run it with sudo. For anything you set up with /etc/sudoers, you need to use the sudo command to allow for those extra privileges.

Code:

sudo force-reboot

ag33k · 01-07-2017, 10:34 PM

It works!

Thanks

pan64 · 01-08-2017, 04:41 AM

if your issue is now solved please mark the thread solved.
Also if you want to say thanks just click on yes.