Sudo Settings2015/11/25

	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]	For 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 35,36: 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 30: add aliase for the kind of shutdown commands

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

# 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:~>

# done normally

suse@dlp:~>

sudo /usr/bin/passwd testuser

Changing password for user testuser.
New UNIX password:

# set testuser's password

Retype new UNIX password:
passwd: all authentication tokens updated successfully.

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

dlp:~ #

visudo

# add at 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=local7

dlp:~ #

vi /etc/syslog-ng/syslog-ng.conf

# line 84: remove "local7"

filter f_local { facility(local0, local1, local2, local3,
local4, local5, local6); };

# line 87: add

filter f_sudo { facility(local7); };

# line 99: add

filter f_messages { not facility(news, mail) and not filter(f_iptables)

and not filter(f_sudo)

; };

# line 219: add

destination sudolog { file("/var/log/sudo.log"); };
log { source(src); filter(f_sudo); destination(sudolog); };

dlp:~ #

/etc/init.d/syslog restart

Shutting down syslog services
Starting syslog services

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