ansible-personal/roles/common/files/update-spamhaus-lists.sh
Alan Orth d7c34a30a3
roles/common: Add Spamhaus DROP lists to firewalld ipsets
This configures the recommended DROP, EDROP, and DROPv6 lists from
Spamhaus as ipsets in firewalld. First we copy an empty placeholder
ipset to seed firewalld, then we use a shell script to download the
real lists and activate them. The same shell script is run daily as
a service (update-spamhaus-lists.service) by a systemd timer.

I am strictly avoiding any direct ipset commands here because I want
to make sure that this works on older hosts where ipsets is used as
well as newer hosts that have moved to nftables such as Ubuntu 20.04.
So far I have tested this on Ubuntu 16.04, 18.04, and 20.04, but ev-
entually I need to abstract the tasks and run them on CentOS 7+ as
well.

See: https://www.spamhaus.org/drop/
2021-07-21 09:34:51 +03:00

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#!/usr/bin/env bash
#
# update-spamhaus-lists.sh v0.0.5
#
# Download Spamhaus DROP lists and load them into firewalld ipsets. Should work
# with both the iptables and nftables backends.
#
# See: https://www.spamhaus.org/drop/
#
# Copyright (C) 2021 Alan Orth
#
# SPDX-License-Identifier: GPL-3.0-only
# Exit on first error
set -o errexit
firewalld_ipsets=$(firewall-cmd --get-ipsets)
xml_temp=$(mktemp)
spamhaus_ipv4_ipset_path=/etc/firewalld/ipsets/spamhaus-ipv4.xml
spamhaus_ipv6_ipset_path=/etc/firewalld/ipsets/spamhaus-ipv6.xml
function download() {
echo "Downloading $1"
wget -q -O - "https://www.spamhaus.org/drop/$1" > "$1"
}
download drop.txt
download edrop.txt
download dropv6.txt
if [[ -f "drop.txt" && -f "edrop.txt" ]]; then
echo "Processing IPv4 DROP lists"
# Extract all networks from drop.txt and edrop.txt, skipping blank lines and
# comments.
networks=$(cat drop.txt edrop.txt | sed -e '/^$/d' -e '/^;.*/d' -e 's/[[:space:]];[[:space:]].*//')
# If firewalld already has this ipset we should delete it first to emulate
# `ipset flush` (but I don't want to use that because newer hosts might be
# using nftables and firewalld will handle that for us).
if [[ "$firewalld_ipsets" =~ spamhaus-ipv4 ]]; then
echo "Deleting existing spamhaus-ipv4 ipset"
# This deletes the firewalld ipset XML file as well as the ipset itself
firewall-cmd --permanent --delete-ipset=spamhaus-ipv4
else
echo "Creating placeholder spamhaus-ipv4 ipset"
# Create a placeholder ipset so firewalld doesn't complain when we try
# to reload the ipset later after having added a new XML definition. I
# don't know why, but depending on the system state there may not be a
# ipset defined and firewalld errors on INVALID_IPSET.
firewall-cmd --permanent --new-ipset=spamhaus-ipv4 --type=hash:net --option=family=inet
fi
# I'm not proud of this, but writing the XML directly is WAY faster than
# using firewall-cmd to add each entry one by one (and we can't add from
# a file because many of our hosts are using old firewalld).
cat << XML_HEAD > "$xml_temp"
<?xml version="1.0" encoding="utf-8"?>
<ipset type="hash:net">
<option name="family" value="inet" />
<short>spamhaus-ipv4</short>
<description>Spamhaus DROP and EDROP lists (IPv4).</description>
XML_HEAD
for network in $networks; do
echo " <entry>$network</entry>" >> "$xml_temp"
done
echo "</ipset>" >> "$xml_temp"
install -m 0600 "$xml_temp" "$spamhaus_ipv4_ipset_path"
fi
if [[ -f "dropv6.txt" ]]; then
echo "Processing IPv6 DROP list"
networks=$(sed -e '/^$/d' -e '/^;.*/d' -e 's/[[:space:]];[[:space:]].*//' dropv6.txt)
if [[ "$firewalld_ipsets" =~ spamhaus-ipv6 ]]; then
echo "Deleting existing spamhaus-ipv6 ipset"
firewall-cmd --permanent --delete-ipset=spamhaus-ipv6
else
echo "Creating placeholder spamhaus-ipv6 ipset"
firewall-cmd --permanent --new-ipset=spamhaus-ipv6 --type=hash:net --option=family=inet6
fi
cat << XML_HEAD > "$xml_temp"
<?xml version="1.0" encoding="utf-8"?>
<ipset type="hash:net">
<option name="family" value="inet6" />
<short>spamhaus-ipv6</short>
<description>Spamhaus DROP lists (IPv6).</description>
XML_HEAD
for network in $networks; do
echo " <entry>$network</entry>" >> "$xml_temp"
done
echo "</ipset>" >> "$xml_temp"
install -m 0600 "$xml_temp" "$spamhaus_ipv6_ipset_path"
fi
echo "Reloading firewalld"
firewall-cmd --reload
rm -v drop.txt edrop.txt dropv6.txt "$xml_temp"