Initial Settings : Configure sudo2014/07/08

	Configure sudo to separate users' duty if some people share privileges. It's unnecessarry to install sudo manually because it is installed by default even if "Minimal Install".
[1]	Transfer root privilege to a user all.

[root@dlp ~]#

visudo

# add at the last line: user 'cent' can use all root privilege

cent    ALL=(ALL)       ALL

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

# make sure with the user 'cent'

[cent@dlp ~]$

/usr/bin/cat /etc/shadow

cat: /etc/shadow: Permission denied

# denied normally

[cent@dlp ~]$

sudo /usr/bin/cat /etc/shadow

[sudo] password for cent:

# own password

daemon:*:16231:0:99999:7:::
adm:*:16231:0:99999:7:::
lp:*:16231:0:99999:7:::
...
...

# just executed

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

[root@dlp ~]#

visudo

# near line 49: add alias for the kind of shutdown commands

Cmnd_Alias SHUTDOWN = /sbin/halt, /sbin/shutdown, \
/sbin/poweroff, /sbin/reboot, /sbin/init

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

cent ALL=(ALL) ALL,

!SHUTDOWN

# make sure with the user 'cent'

[cent@dlp ~]$

sudo /sbin/shutdown -r now

Sorry, user cent is not allowed to execute '/sbin/shutdown -r now' as root on dlp.srv.world.

# denied normally

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

[root@dlp ~]#

visudo

# near line 51: add alias for the kind of user management comamnds

Cmnd_Alias USERMGR = /usr/sbin/useradd, /usr/sbin/userdel, /usr/sbin/usermod, \
/usr/bin/passwd

# add at the last line

%usermgr ALL=(ALL) USERMGR

[root@dlp ~]#

groupadd usermgr

[root@dlp ~]#

usermod -aG usermgr cent

# make sure with the user 'cent'

[cent@dlp ~]$

sudo /usr/sbin/useradd testuser

[cent@dlp ~]$

# done normally

[cent@dlp ~]$

sudo /usr/bin/passwd testuser

Changing password for user testuser.
New UNIX password:
Retype new UNIX password:
passwd: all authentication tokens updated successfully.

[4]	Transfer a command with root privilege to a user.

[root@dlp ~]#

visudo

# add at the last line

cent    ALL=(ALL) /usr/sbin/visudo
fedora  ALL=(ALL) /usr/sbin/useradd, /usr/sbin/userdel, /usr/sbin/usermod, /usr/bin/passwd
ubuntu  ALL=(ALL) /bin/vi

# make sure with the user 'cent'

[cent@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.
##

# make sure with the user 'fedora'

[fedora@dlp ~]$

sudo /usr/sbin/userdel -r testuser

[fedora@dlp ~]$

# done normally

# make sure with the user 'ubuntu'

[ubuntu@dlp ~]$

sudo /bin/vi /boot/grub/grub.conf

# possible to open and edit

# grub.conf generated by anaconda
#
# Note that you do not have to rerun grub after making changes to this file
# NOTICE: You have a /boot partition. This means that

[5]	The logs for sudo are kept in '/var/log/secure', 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 at the last line

Defaults syslog=local1

[root@dlp ~]#

vi /etc/rsyslog.conf

# line 54: add

*.info;mail.none;authpriv.none;cron.none

;local1.none

/var/log/messages

# add the line, too

local1.*                                                /var/log/sudo.log

[root@dlp ~]#

systemctl restart rsyslog

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