Sudo Settings2016/04/21

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

root@dlp:~#

apt-get -y install sudo

[2]	Transfer root privilege to a user all.

root@dlp:~#

visudo

# add to the end: user 'xerus' can use all root privilege

xerus ALL=(ALL:ALL) ALL

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

# push 'Ctrl + x' key to quit visudo

# verify with user 'xerus'

xerus@dlp:~$

/sbin/shutdown -r now

shutdown: Need to be root

# denied normally

xerus@dlp:~$

sudo /sbin/shutdown -r now

[sudo] password for xerus:

# xerus's password


Broadcast message from root@dlp
        (/dev/pts/0) at 17:33 ...

The system is going down for reboot NOW!

# executed

[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

# add ( commands in alias 'SHUTDOWN' are not allowed )

xerus ALL=(ALL) ALL,

!SHUTDOWN

# verify with user 'xerus'

xerus@dlp:~$

sudo /sbin/shutdown -r now

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

xerus

# verify with user 'xerus'

xerus@dlp:~$

sudo /usr/sbin/useradd testuser

xerus@dlp:~$

# done normally

xerus@dlp:~$

sudo /usr/bin/passwd testuser

Enter new UNIX password:

# set testuser's 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.d/50-default.conf

# line 8: add

local1.*                        /var/log/sudo.log

auth,authpriv.*                 /var/log/auth.log
*.*;auth,authpriv.none          -/var/log/syslog

root@dlp:~#

systemctl restart rsyslog

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