[CONTACT]

[ABOUT]

[POLICY]

This is a only version

Found at: raymii.org:70/Check_if_passwordless_sudo_can_be_used_in_a_bash_script_or_nagios_check.txt

This is a text-only version of the following page on https://raymii.org:
---
Title       : 	Check if passwordless sudo can be used in a bash script or nagios check
Author      : 	Remy van Elst
Date        : 	30-01-2014
URL         : 	https://raymii.org/s/articles/Check_if_passwordless_sudo_can_be_used_in_a_bash_script_or_nagios_check.html
Format      : 	Markdown/HTML
---
This is a simple trick to see if you can use passwordless sudo in a script. This
for example can be usefull in a Nagios plugin which requires sudo. Instead of
putting the sudo line in your README and otherwise having a NRPE Unable to parse
result error, you could just give a nice warning message plus the right sudo
configuration rule.

I'm developing an open source monitoring app called Leaf Node Monitoring, for windows, linux & android. Go check it out!

Consider sponsoring me on Github. It means the world to me if you show your appreciation and you'll help pay the server costs.

You can also sponsor me by getting a Digital Ocean VPS. With this referral link you'll get $100 credit for 60 days.

The example below comes from a Nagios plugin which checks if an [OSSEC][2]
server has disconnected agents. The nagios user should have a special exception
in `/etc/sudoers` to allow calling the ossec command with elevated privileges.
If the sudo is not successful it gives a nice error plus the required config to
add to `/etc/sudoers`:
    
    
    AGENTS="$(sudo -n /var/ossec/bin/list_agents -n 2>&1)"
    if [[ ${?} != "0" ]]; then
        echo "UNKNOWN: Unable to execute list_agents. Is sudo configured?"
        echo "Add the following to /etc/sudoers USING VISUDO!:"
        echo -e "$(whoami)\tALL=NOPASSWD:\t${DIRECTORY}/bin/list_agents -n"
        exit 3
    fi
    
Instead of seeing a "Unable to parse output" error in Nagios we get a nice
UNKNOWN warning actually telling us what's wrong, like so:
    
    
    # sudo -u nagios  bash /etc/nagios-plugins/ossec-agents.sh
    UNKNOWN: Unable to execute list_agents. Is sudo configured?
    Add the following to /etc/sudoers USING VISUDO!:
    nagios  ALL=NOPASSWD:  /var/ossec/bin/list_agents -n
    
The trick is using the `-n` / non-interactive option with sudo. The [man
page][3] tells us the following:
    
    
    -n' The -n (non-interactive) option prevents sudo from prompting the user for a password. If a password is required for the command to run, sudo will display an error message and exit. 
    
Which is perfect to test passwordless login instead of letting it just fail.
   [1]: https://www.digitalocean.com/?refcode=7435ae6b8212
   [2]: http://www.ossec.net/
   [3]: http://linux.die.net/man/8/sudo
---
License:
All the text on this website is free as in freedom unless stated otherwise. 
This means you can use it in any way you want, you can copy it, change it 
the way you like and republish it, as long as you release the (modified) 
content under the same license to give others the same freedoms you've got 
and place my name and a link to this site with the article as source.
This site uses Google Analytics for statistics and Google Adwords for 
advertisements. You are tracked and Google knows everything about you. 
Use an adblocker like ublock-origin if you don't want it.
All the code on this website is licensed under the GNU GPL v3 license 
unless already licensed under a license which does not allows this form 
of licensing or if another license is stated on that page / in that software:
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.
    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
    You should have received a copy of the GNU General Public License
    along with this program.  If not, see .
Just to be clear, the information on this website is for meant for educational 
purposes and you use it at your own risk. I do not take responsibility if you 
screw something up. Use common sense, do not 'rm -rf /' as root for example. 
If you have any questions then do not hesitate to contact me.
See https://raymii.org/s/static/About.html for details.


AD: