Ubuntu - Sudo - Configure privileges

sudo visudo

Add to the end to allow testuser all root privileges:

visudo

...
testuser    ALL=(ALL:ALL) ALL

[user] [host=(owner)] [command]

Push [Ctrl + x] key to quit visudo.

</code bash> testuser@sharewiz:~$ /sbin/reboot

Failed to set wall message, ignoring: Interactive authentication required. Failed to reboot system via logind: Interactive authentication required. Failed to open /dev/initctl: Permission denied Failed to talk to init daemon. # denied normally </code>

testuser@sharewiz:~$ sudo /sbin/reboot

Session terminated, terminating shell… # run normally

Add settings that some commands are not allowed.

sudo visudo

Add alias for the kind of shutdown commands:

visudo

# Cmnd alias specification
 
Cmnd_Alias SHUTDOWN = /sbin/halt, /sbin/shutdown, \
/sbin/poweroff, /sbin/reboot, /sbin/init, /bin/systemctl 
 
...
 
# Add (commands in alias [SHUTDOWN] are not allowed)
testuser    ALL=(ALL:ALL) ALL, !SHUTDOWN

With user testuser

sudo /sbin/shutdown -r now

returns:

Sorry, user testuser  is not allowed to execute '/sbin/shutdown -r now' as root on ubuntu.

sudo visudo

Add aliases for the kind of user management comamnds:

visudo

# Cmnd alias specification
Cmnd_Alias USERMGR = /usr/sbin/adduser, /usr/sbin/useradd, /usr/sbin/newusers, \
/usr/sbin/deluser, /usr/sbin/userdel, /usr/sbin/usermod, /usr/bin/passwd 
 
...
 
# add to the end
%usermgr ALL=(ALL) USERMGR

sudo groupadd usermgr

vi /etc/group
# add a user in this group
 
usermgr:x:1002:testuser

Verify with user testuser

sudo /usr/sbin/useradd testuser
sudo /usr/bin/passwd testuser
 
Enter new UNIX password:
Retype new UNIX password:
passwd: password updated successfully

sudo visudo

Add to the end

visudo

...
testuser1    ALL=(ALL:ALL) /usr/sbin/visudo
testuser2    ALL=(ALL:ALL) /usr/sbin/adduser, /usr/sbin/useradd, /usr/sbin/newusers, \
                        /usr/sbin/deluser, /usr/sbin/userdel, /usr/sbin/usermod, /usr/bin/passwd
testuser2    ALL=(ALL:ALL) /usr/bin/vim

Verify with user testuser1.

sudo /usr/sbin/visudo
# run normally

Sudoers allows particular users to run various commands as the root user, without needing the root password.

Verify with user testuser2

sudo /usr/sbin/userdel -r testuser

Verify with user testuser3

sudo /usr/bin/vim /root/.profile

~/.profile: executed by Bourne-compatible login shells.

The logs for sudo are kept in '/var/log/auth.log', but there are many kind of logs in it.

So if you'd like to keep only sudo's log in another file, Set like follows.

sudo visudo

visudo

...
# Add to the end
 
Defaults syslog=local1

Edit /etc/rsyslog.d/50-default.conf as root.

/etc/rsyslog.d/50-default.conf

# line 8: add
 
local1.*                        /var/log/sudo.log
 
auth,authpriv.*;local1.none     /var/log/auth.log
*.*;auth,authpriv.none          -/var/log/syslog

sudo systemctl restart rsyslog