Using squid, squidGuard, havp, and ramdisk as an antivirus proxy & internet filter

For a couple of years I have used havp in my home. Since my web/email server is in my home and already running clamav as my antivirus, once I learned that I could route all my internet traffic through havp proxy, it was a no-brainer that I needed to do this as another layer of protection for my home computers. Setup was straightforward, I just downloaded, ran the usual configure/make/make install, and it worked. The only tricky part was setting up the mandatory locking on the file system. Initially I had a spare hard drive in the server that I just remounted with mandatory locking and all was fine.
Then a few things happened around the same time. First, I needed that spare hard drive to go into a refurbished computer that went to my father-in-law. Time to use a ramdisk for my havp scanning filesystem. Next, my son (now 10) started using the web more. Time for a filter.

This post will document how I implemented the squidGuard proxy server as a content filter, havp as an antivirus proxy, with a ramdisk as the havp scanning filesystem. Getting the ramdisk to mount with each reboot took some work, so here’s what I did.

First, the ramdisk. Hopefully someone can correct me, but I found that I could not simply put a line in my /etc/fstab for the ramdisk and just have it get mounted with a system reboot. Reboots are pretty rare, but this is the problem… they are so rare that when they do happen, I have to re-learn (a la google) how to create the ramdisk properly, then when starting havp fails I have to re-remember that I have to reset permissions on the mounted ramdisk, etc. Time for a script. Here’s my script, called /usr/local/bin/mount-havp-ramdisk.sh:

#! /bin/bash
# HAVP requires a filesystem with mandatory locks.
# I use a ramdisk for the filesystem, which must be created
# before use by HAVP.
# The script is called from the /etc/init.d/havp startup script,
# and verifies that the ramdisk exists and is mounted, and if not
# it creates it and sets proper permissions.

# Set some variables
RAMDISK=/dev/ram0
MOUNTPOINT=/var/tmp/havp
HAVPUSER=havp

#
# If the ramdisk is already exists and is mounted, then no need to continue.
#
MP="`/bin/mount |/bin/grep $RAMDISK`"
if [ "$MP" != "" ]; then
        # ramdisk is mounted; exit with success.
        exit 0;
fi

#
# Since ramdisk not mounted, we won't assume it exists.
# First we'll create the ramdisk, then mount it with mandatory locking
# and finally set permissions
#
/sbin/mke2fs -q -m 0 /dev/ram0 && \
        /bin/mount -o mand $RAMDISK $MOUNTPOINT && \
        /bin/chown $HAVPUSER:root $MOUNTPOINT && \
        /bin/chmod 0750 $MOUNTPOINT
exit $?

Source : http://drhymel.com/blog/?p=25