initial version

firewall.user

@@ -0,0 +1,64 @@
+#!/bin/sh
+
+# IP blacklisting script for OpenWRT routers
+# Pawel Krawczyk https://keybase.io/kravietz
+#
+# This script should be *only* used on OpenWRT as it relies on uci configuration framework
+# specific to these routers. 
+#
+# This file should be installed as /etc/firewall.user and then updated from crontab:
+#
+# 01 01 * * * sh /etc/firewall.user
+#
+
+# Emerging Threats lists offensive IPs such as botnet command servers
+urls="http://rules.emergingthreats.net/fwrules/emerging-Block-IPs.txt"
+# Bogons lists IP addresses that should never appear on public Internet
+# including RFC 1918 networks - this is why this script blocks packets only
+# on WAN interface of an OpenWRT router
+urls="$urls http://www.team-cymru.org/Services/Bogons/fullbogons-ipv4.txt"
+# Blocklist.de collects reports from fail2ban probes, listing password brute-forces, scanners and other offenders
+urls="$urls https://www.blocklist.de/downloads/export-ips_all.txt"
+
+blocklist_chain_name=blocklists
+
+if [ ! -x /usr/sbin/ipset ]; then
+    echo "Cannot find ipset"
+    echo "Run: opkg update && opkg install ipset"
+    exit 1
+fi
+
+# create main blocklists chain
+if ! iptables -L ${blocklist_chain_name}; then iptables -N ${blocklist_chain_name}; fi
+
+# inject references to blocklist in the beginning of input and forward chains
+if ! iptables -L input|grep -q ${blocklist_chain_name}; then
+  iptables -I input 1 -m state --state NEW,RELATED -j ${blocklist_chain_name}
+fi
+if ! iptables -L forward|grep -q ${blocklist_chain_name}; then
+  iptables -I forward 1 -m state --state NEW,RELATED -j ${blocklist_chain_name}
+fi                                                                 
+
+wan_iface=$(uci get network.wan.ifname)
+if [ -z "$wan_iface" ]; then
+    echo "Cannot determine WAN interface"
+    exit 1
+fi
+
+iptables -F ${blocklist_chain_name}
+                                                                      
+for url in $urls; do
+    tmp=$(mktemp)
+    tmp2=$(mktemp)
+    set_name=$(basename $url)
+    curl --compressed -k "$url" >"$tmp"
+    sort -u <"$tmp" | egrep "^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$" >"$tmp2"
+    ipset -! create ${set_name} hash:net
+    while read line; do
+        ipset add ${set_name} "$line"
+    done <"$tmp2"
+    iptables -A ${blocklist_chain_name} -i "${wan_iface}" -m set --match-set "${set_name}" src,dst -m limit --limit 10/minute -j LOG --log-prefix "BLOCK ${set_name} "
+    iptables -A ${blocklist_chain_name} -i "${wan_iface}" -m set --match-set "${set_name}" src,dst -j DROP
+    echo ${set_name} $(ipset list ${set_name} | wc -l)
+done
+