Sudo Settings2017/06/18

	Configure Sudo to separate users' duty if some people share privileges.
[1]	Install Sudo.

root@dlp:~#

apt -y install sudo

[2]	Transfer root privilege to a user all.

root@dlp:~#

visudo

# add to the end: user [stretch] can use all root privilege

stretch ALL=(ALL) ALL

# how to write ⇒ destination host=(owner) command

# push [Ctrl + x] key to quit visudo

# verify with user [stretch]

stretch@dlp:~$

/sbin/shutdown -r now

shutdown: you must be root to do that!

# denied normally

stretch@dlp:~$

sudo /sbin/shutdown -r now

[sudo] password for stretch:

# stretch's password

stretch@dlp:~$

Broadcast message from root@dlp (pts/0) (Sun May 6 02:45:10 2011):

The system is going down for reboot NOW!

# possible execute

[3]	In addition to the setting [1], set that some commands are not allowed.

root@dlp:~#

visudo

# add alias for the kind of shutdown commands

# 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 )

stretch ALL=(ALL) ALL,

!SHUTDOWN

# verify with user [stretch]

stretch@dlp:~$

sudo /sbin/shutdown -r now

[sudo] password for stretch:
Sorry, user stretch is not allowed to execute '/sbin/shutdown -r now' as root on dlp.srv.world.

# denied normally

[4]	Transfer some commands with root privilege to users in a group.

root@dlp:~#

visudo

# add aliase for the kind of user management comamnds

# 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

root@dlp:~#

groupadd usermgr

root@dlp:~#

vi /etc/group

# add a user in this group

usermgr:x:1002:

stretch

# verify with user [stretch]

stretch@dlp:~$

sudo /usr/sbin/useradd testuser

stretch@dlp:~$

# done normally

stretch@dlp:~$

sudo /usr/bin/passwd testuser

Enter new UNIX password:
Retype new UNIX password:
passwd: password updated successfully

[5]	Transfer some commands with root privilege to a user.

root@dlp:~#

visudo

# add to the end

fedora ALL=(ALL) /usr/sbin/visudo
cent ALL=(ALL) /usr/sbin/adduser, /usr/sbin/useradd, /usr/sbin/newusers, \
/usr/sbin/deluser, /usr/sbin/userdel, /usr/sbin/usermod, /usr/bin/passwd
suse ALL=(ALL) /usr/bin/vim

# verify with user [fedora]

fedora@dlp:~$

sudo /usr/sbin/visudo

# possible to open and edit

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

# verify with user [cent]

cent@dlp:~$

sudo /usr/sbin/userdel -r testuser

cent@dlp:~$

# done normally

# verify with user [suse]

suse@dlp:~$

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

# possible to edit or save

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

[6]	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 a file, Set like follows.

root@dlp:~#

visudo

# add to the end

Defaults syslog=local1

root@dlp:~#

vi /etc/rsyslog.conf

# line 61: add

local1.*                     /var/log/sudo.log
auth,authpriv.*          /var/log/auth.log

root@dlp:~#

systemctl restart rsyslog

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