RHEL / CentOS Linux: Nginx Chroot Jail Start / Stop / Restart Shell Script

RHEL / CentOS Linux: Nginx Chroot Jail Start / Stop / Restart Shell Script

simple shell script to start / stop / restart chrooted nginx web server under CentOS / RHEL Linux. You must have Nginx web server setup in a chroot (jail) so that you can minimizes the damage done by a potential break-in by isolating the web server to a small section of the filesystem. You can also mount $jail/tmp as a separate filesystem (/images/tmpfile.bin) with the noexec,nosuid, nodev options under Linux like operating systems.

#!/bin/bash

# Name : nginx.rc  

# URL: http://bash.cyberciti.biz/security/linux-nginx-start-stop-restart-chrooted-jail/

# Purpose: A simple shell script wrapper to chroot nginx in $_newroot under Linux

# ----------------------------------------------------------------------------

# Author: nixCraft

# Copyright: 2011 nixCraft under GNU GPL v2.0+

# ----------------------------------------------------------------------------

# Last updated: 18/Dec/2012 - Added support for secure /tmp mount

# Last updated: 19/Dec/2012 - Bug fixed in ln 

# Last updated: 10/Mar/2013 - Bug fixed in status()

# ----------------------------------------------------------------------------

 

# jail location - must be up, see how to setup nginx using chroot

# http://www.cyberciti.biz/faq/howto-run-nginx-in-a-chroot-jail/

_newroot="/nginxjail"

 

# RHEL nginx and other binary paths

_nginx="/usr/sbin/nginx"

_chroot="/usr/sbin/chroot"

_killall="/usr/bin/killall"

 

# 0 turn off or # 1 turn on

_securetmp=0

_securetmproot="/path/to/images/nginx_jail_tmp.bin"

 

 

[ ! -d "$_newroot" ] &# mount /tmp securely inside $_newroot

# see http://www.cyberciti.biz/faq/howto-mount-tmp-as-separate-filesystem-with-noexec-nosuid-nodev/

mounttmp(){

if [ $_securetmp -eq 1 ]

then

mount | grep -q $_securetmproot

if [ $? -eq  0 ]

then

echo "*** Secure root enabled and mounted ***"

else

echo "*** Turning on secure /tmp..."

[ ! -f "$_securetmproot" ] &mount -o loop,noexec,nosuid,rw "$_securetmproot" "$_newroot/tmp"

chmod 1777 "$_newroot/tmp"

rm -rf "$_newroot/var/tmp"

ln -s ../tmp "$_newroot/var/tmp"

fi

fi

}

 

start(){

echo -en "Starting nginx...\t\t\t"

$_chroot $_newroot $_nginx && echo -en "[ OK ]" || echo "[ Failed ]"

}

 

stop(){

echo -en "Stoping nginx...\t\t\t"

$_killall "${_nginx##*/}" && echo -en "[ OK ]" || echo "[ Failed ]"

}

 

reload(){

echo -en "Reloading nginx...\t\t\t"

$_chroot $_newroot $_nginx -s reload && echo -en "[ OK ]" || echo "[ Failed ]"

}

 

## Fancy status

status(){

echo 

pgrep -u ${_nginx##*/} ${_nginx##*/} &>/dev/null

[ $? -eq 0 ] && echo "*** Nginx running on $(hostname) ***" || echo "*** Nginx not found on $(hostname) ***"

echo 

echo "*** PID ***"

#pgrep -u ${_nginx##*/} ${_nginx##*/}

ps aux | grep "${_nginx##*/}" | egrep -v 'grep|bash'

echo

 

echo "FD stats:"

for p in $(pidof ${_nginx##*/}); do echo "PID # $p has $(lsof -n -a -p $p|wc -l) fd opend."; done

echo

 

echo "Jail dir location:"

pwdx $(pgrep -u "root" "${_nginx##*/}") | grep  --color "$_newroot"

echo 

 

echo "*** PORT ***"

netstat -tulpn | egrep --color  ':80|:443'

}

 

## Make sure /tmp is securely mounted inside jail ##

mounttmp

 

## main ##

case "$1" in

        start)

                start 

                ;;

        stop)

                stop 

                ;;

        restart)

                stop 

                start 

                ;;

        reload)

                reload

;; 

        status)

                status

                ;;

        *)

                echo $"Usage: $0 {start|stop|restart|reload|status}"

                ;;

esac

 

# just send \n

echo

How do I use this script?

Download the script:# cd /tmp
# wget http://bash.cyberciti.biz/dl/593.sh.zip
# unzip 593.sh.zip
# mv 593.sh /etc/rc.d/nginx.jail.rc
# chmod +x /etc/rc.d/nginx.jail.rc
Use it as follows:# /etc/rc.d/nginx.jail.rc start
# /etc/rc.d/nginx.jail.rc stop
# /etc/rc.d/nginx.jail.rc restart
# /etc/rc.d/nginx.jail.rc status
Sample outputs:

Fig.01 nginx.rc in action