#!/bin/bash # # Based on https://lists.torproject.org/pipermail/tor-talk/2014-March/032503.html # See also: # # https://trac.torproject.org/projects/tor/wiki/doc/TransparentProxy #- https://askubuntu.com/questions/324685/how-to-route-all-internet-traffic-through-tor-the-onion-router #- https://tor.stackexchange.com/questions/12343/use-iptables-to-force-traffic-through-tor #- https://tails.boum.org/contribute/design/Tor_enforcement/Network_filter/ #- https://git.tails.boum.org/tails/plain/config/chroot_local-includes/etc/ferm/ferm.conf #- https://git.tails.boum.org/tails/plain/config/chroot_local-includes/etc/tor/torrc #- https://trac.torproject.org/projects/tor/wiki/doc/DnsResolver #- https://trac.torproject.org/projects/tor/wiki/doc/PreventingDnsLeaksInTor # Parameters IPTABLES=/sbin/iptables TOR_UID=`id -u debian-tor` NETWORK_USER_ID=1000 # Clear existing rules $IPTABLES -F INPUT || exit $IPTABLES -F OUTPUT || exit $IPTABLES -t nat -F || exit # Transproxy rules for Tor $IPTABLES -t nat -A OUTPUT ! -d 127.0.0.1 -m owner ! --uid-owner $TOR_UID -p tcp -j REDIRECT --to-ports 9040 || exit $IPTABLES -t nat -A OUTPUT -p udp -m owner ! --uid-owner $TOR_UID -m udp --dport 53 -j REDIRECT --to-ports 5353 || exit # Allow Tor, _apt, root and the network user $IPTABLES -A OUTPUT -m owner --uid-owner $TOR_UID -j ACCEPT || exit $IPTABLES -A OUTPUT -m owner --uid-owner $NETWORK_USER_ID -j ACCEPT || exit $IPTABLES -A OUTPUT -m owner --uid-owner root -j ACCEPT || exit $IPTABLES -A OUTPUT -m owner --uid-owner _apt -j ACCEPT || exit $IPTABLES -A INPUT -j LOG --log-prefix "OUTPUT DROPPED: " --log-uid || exit $IPTABLES -A OUTPUT -j DROP || exit # Allow SSH $IPTABLES -A INPUT -p tcp --dport ssh -j ACCEPT || exit # Create INPUT firewall. Allow established connections and transproxy $IPTABLES -A INPUT -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT || exit $IPTABLES -A INPUT -i lo -j ACCEPT || exit # Transproxy output comes from lo $IPTABLES -A INPUT -d 127.0.0.1 -m udp -p udp --dport 5300 -j ACCEPT || exit $IPTABLES -A INPUT -j LOG --log-prefix "INPUT DROPPED: " --log-uid || exit $IPTABLES -A INPUT -j DROP || exit # Avoid packet leaks # https://lists.torproject.org/pipermail/tor-talk/2014-March/032507.html #iptables -I OUTPUT ! -o lo ! -d 127.0.0.1 ! -s 127.0.0.1 -p tcp -m tcp --tcp-flags ACK,FIN ACK,FIN -j DROP #iptables -I OUTPUT ! -o lo ! -d 127.0.0.1 ! -s 127.0.0.1 -p tcp -m tcp --tcp-flags ACK,RST ACK,RST -j DROP #iptables -A OUTPUT -m conntrack --ctstate INVALID -j LOG --log-prefix "Transproxy ctstate leak blocked: " --log-uid iptables -A OUTPUT -m conntrack --ctstate INVALID -j DROP || exit iptables -A OUTPUT -m state --state INVALID -j LOG --log-prefix "Transproxy state leak blocked: " --log-uid || exit iptables -A OUTPUT -m state --state INVALID -j DROP || exit iptables -A OUTPUT ! -o lo ! -d 127.0.0.1 ! -s 127.0.0.1 -p tcp -m tcp --tcp-flags ACK,FIN ACK,FIN -j LOG --log-prefix "Transproxy leak blocked: " --log-uid || exit iptables -A OUTPUT ! -o lo ! -d 127.0.0.1 ! -s 127.0.0.1 -p tcp -m tcp --tcp-flags ACK,RST ACK,RST -j LOG --log-prefix "Transproxy leak blocked: " --log-uid || exit iptables -A OUTPUT ! -o lo ! -d 127.0.0.1 ! -s 127.0.0.1 -p tcp -m tcp --tcp-flags ACK,FIN ACK,FIN -j DROP || exit iptables -A OUTPUT ! -o lo ! -d 127.0.0.1 ! -s 127.0.0.1 -p tcp -m tcp --tcp-flags ACK,RST ACK,RST -j DROP || exit