Initial Settings : Configure Sudo2019/01/14

	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]	On SUSE Linux, root password is required when using sudo by default settings, so change it that users can authenticate with their own password when using sudo.

dlp:~ #

visudo

# line 68,69: comment out

##Defaults targetpw
##ALL   ALL=(ALL) ALL

[2]	Transfer root privilege to a user all.

dlp:~ #

visudo

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

suse ALL=(ALL) ALL

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

# verify with user [suse]

suse@dlp:~>

/bin/cat /etc/shadow

/bin/cat: /etc/shadow: Permission denied

# denied normally

suse@dlp:~>

sudo /bin/cat /etc/shadow

suse's password:

# own password

...
...
uucp:*:16357::::::
wwwrun:*:16357::::::

# just executed

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

dlp:~ #

visudo

# near line 31: add aliase for the kind of shutdown commands

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

# add ( commands in aliase [SHUTDOWN] are not allowed )

suse ALL=(ALL) ALL,

!SHUTDOWN

# verify with user [suse]

suse@dlp:~>

sudo /sbin/shutdown -r now

Password:
Sorry, user suse is not allowed to execute '/sbin/shutdown -r now' as root on dlp.

# 拒否された

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

dlp:~ #

visudo

# near line 30: add aliase for the kind of user management comamnds

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

# add to the end

%usermgr ALL=(ALL) USERMGR

dlp:~ #

groupadd usermgr

dlp:~ #

usermod -G usermgr suse

# verify with user [suse]

suse@dlp:~>

sudo /usr/sbin/useradd testuser

suse@dlp:~>

# run normally

suse@dlp:~>

sudo /usr/bin/passwd testuser

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

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

dlp:~ #

visudo

# add to the end

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

# verify with user [suse]

suse@dlp:~>

sudo /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 /sbin/userdel -r testuser

cent@dlp:~>

# done normally

# verify with user [ubuntu]

ubuntu@dlp:~>

sudo /bin/vi /boot/grub2/grub.cfg

# 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

[6]	The logs for sudo are kept in [/var/log/messages], but there are many kind of logs in it. If you'd like to keep only sudo's log in another file, Configure like follows.

dlp:~ #

visudo

# add to the end

Defaults syslog=local1

dlp:~ #

vi /etc/rsyslog.conf

# line 168: add

*.*;mail.none;news.none;local1.none     -/var/log/messages

# line 180: remove [local1]

local0.*                      -/var/log/localmessages

# add to the end

local1.*                       -/var/log/sudo.log

dlp:~ #

systemctl restart rsyslog

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