diff options
| -rwxr-xr-x | target/default/target_skeleton/etc/init.d/S45firewall | 101 |
1 files changed, 76 insertions, 25 deletions
diff --git a/target/default/target_skeleton/etc/init.d/S45firewall b/target/default/target_skeleton/etc/init.d/S45firewall index 51f3a6d1fe..da9fd550f3 100755 --- a/target/default/target_skeleton/etc/init.d/S45firewall +++ b/target/default/target_skeleton/etc/init.d/S45firewall @@ -1,36 +1,87 @@ #!/bin/sh . /etc/functions.sh - export WAN=$(nvram get wan_ifname) -export IPT=/usr/sbin/iptables +export LAN=$(nvram get lan_ifname) -for T in filter nat mangle ; do - $IPT -t $T -F - $IPT -t $T -X +## CLEAR TABLES +for T in filter nat mangle; do + iptables -t $T -F + iptables -t $T -X done -# initial rules -$IPT -t filter -A INPUT -m state --state INVALID -j DROP -$IPT -t filter -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT -$IPT -t filter -A FORWARD -m state --state INVALID -j DROP -$IPT -t filter -A FORWARD -m state --state RELATED,ESTABLISHED -j ACCEPT +iptables -N input_rule +iptables -N output_rule +iptables -N forwarding_rule + +iptables -t nat -N prerouting_rule +iptables -t nat -N postrouting_rule + +### Port forwarding +# iptables -t nat -A prerouting_rule -p tcp --dport 22 -j DNAT --to 192.168.1.2 +# iptables -A forwarding_rule -p tcp --dport 22 -d 192.168.1.2 -j ACCEPT + +### INPUT +### (connections with the router as destination) + + # base case + iptables -P INPUT DROP + iptables -A INPUT -m state --state INVALID -j DROP + iptables -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT + + # allow + iptables -A INPUT -i \! $WAN -j ACCEPT # allow from lan/wifi interfaces + iptables -A INPUT -p icmp -j ACCEPT # allow ICMP + iptables -A INPUT -p 47 -j ACCEPT # allow GRE + # + # insert accept rule or to jump to new accept-check table here + # + iptables -A INPUT -j input_rule + + # reject (what to do with anything not allowed earlier) + iptables -A INPUT -p tcp --syn --tcp-option \! 2 -j DROP + iptables -A INPUT -p tcp -j REJECT --reject-with tcp-reset + iptables -A INPUT -j REJECT --reject-with icmp-port-unreachable + +### OUTPUT +### (connections with the router as source) + + # base case + iptables -P OUTPUT DROP + iptables -A OUTPUT -m state --state INVALID -j DROP + iptables -A OUTPUT -m state --state RELATED,ESTABLISHED -j ACCEPT + + # allow + iptables -A OUTPUT -j ACCEPT #allow everything out + # + # insert accept rule or to jump to new accept-check table here + # + iptables -A OUTPUT -j output_rule + + # reject (what to do with anything not allowed earlier) + iptables -A OUTPUT -p tcp -j REJECT --reject-with tcp-reset + iptables -A OUTPUT -j REJECT --reject-with icmp-port-unreachable -if [ -d /etc/firewall.d ]; then - for fw in /etc/firewall.d/??*; do - [ -x $fw ] && $fw - done -fi +### FORWARDING +### (connections routed through the router) -# defaults + # base case + iptables -P FORWARD DROP + iptables -A FORWARD -m state --state INVALID -j DROP + iptables -A FORWARD -m state --state RELATED,ESTABLISHED -j ACCEPT + iptables -A FORWARD -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu -$IPT -t filter -A INPUT -p icmp -j ACCEPT -$IPT -t filter -A INPUT -p 47 -j ACCEPT # allow GRE -$IPT -t filter -A INPUT -i $WAN -p tcp --syn --tcp-option \! 2 -j DROP -$IPT -t filter -A INPUT -i $WAN -p tcp -j REJECT --reject-with tcp-reset -$IPT -t filter -A INPUT -i $WAN -j REJECT --reject-with icmp-port-unreachable + # allow + iptables -A FORWARD -i br0 -o br0 -j ACCEPT + iptables -A FORWARD -i $LAN -o $WAN -j ACCEPT + # + # insert accept rule or to jump to new accept-check table here + # + iptables -A FORWARD -j forwarding_rule -$IPT -t filter -A FORWARD -i br0 -o br0 -j ACCEPT -$IPT -t filter -A FORWARD -i $WAN -m state --state NEW -j DROP -$IPT -t filter -A FORWARD -o $WAN -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu + # reject (what to do with anything not allowed earlier) + # uses the default -P DROP -$IPT -t nat -A POSTROUTING -o $WAN -j MASQUERADE +### MASQ + iptables -t nat -A PREROUTING -j prerouting_rule + iptables -t nat -A POSTROUTING -j postrouting_rule + iptables -t nat -A POSTROUTING -o $WAN -j MASQUERADE |