diff options
Diffstat (limited to 'roles/common/files/usr')
| -rwxr-xr-x | roles/common/files/usr/local/sbin/update-firewall.sh | 29 |
1 files changed, 20 insertions, 9 deletions
diff --git a/roles/common/files/usr/local/sbin/update-firewall.sh b/roles/common/files/usr/local/sbin/update-firewall.sh index a8123f9..0907ffc 100755 --- a/roles/common/files/usr/local/sbin/update-firewall.sh +++ b/roles/common/files/usr/local/sbin/update-firewall.sh @@ -147,11 +147,13 @@ run() { | sed -nr "/^[0-9]+:\s+(sec[0-9]+)@$if:\s.*/ {s//\1/p;q}" ) # The (host-scoped) IP reserved for IPSec. - local ipsec= + local ipsec= secmark if [ -n "$ifsec" -a $f = 4 ]; then tables[$f]='mangle nat filter' ipsec=$( /bin/ip -$f address show dev "$ifsec" scope host \ | sed -nr '/^\s+inet\s(\S+).*/ {s//\1/p;q}' ) + # /!\ This mark much match that in /etc/network/if-up.d/ipsec. + secmark=0xA99 fi # Store the old (current) ruleset @@ -251,7 +253,7 @@ run() { # $ipsec. Also ACCEPT all traffic originating from $ipsec, as # it is MASQUERADE'd. iptables -A INPUT -d "$ipsec" -i $if -m policy --dir in --pol ipsec -j ACCEPT - iptables -A OUTPUT -s "$ipsec" -o $if -j ACCEPT + iptables -A OUTPUT -m mark --mark "$secmark" -o $if -j ACCEPT fi # Prepare fail2ban. We make fail2ban insert its rules in a @@ -322,22 +324,31 @@ run() { ipt-chains mangle PREROUTING:ACCEPT INPUT:ACCEPT \ FORWARD:DROP \ OUTPUT:ACCEPT POSTROUTING:ACCEPT + # Packets which destination is $ipsec *must* be associated with # an IPSec policy. iptables -A INPUT -d "$ipsec" -i $if -m policy --dir in --pol none -j DROP + + # Packets originating from our (non-routable) $ipsec are marked; + # if there is no xfrm lookup (i.e., no matching IPSec + # association), the packet will retain its mark and be null + # routed later on. Otherwise, the packet is re-queued unmarked. + iptables -A OUTPUT -o $if -j MARK --set-mark 0x0 + iptables -A OUTPUT -s "$ipsec" -o $if -m policy --dir out --pol none \ + -j MARK --set-mark $secmark commit ipt-chains nat PREROUTING:ACCEPT INPUT:ACCEPT \ OUTPUT:ACCEPT POSTROUTING:ACCEPT - # DNAT all marked packets after decapsulation. Packets - # originating from our IPSec are SNAT'ed (MASQUERADE). XXX: - # xfrm lookup occurs *after* NAT POSTROUTING, so sadly we can't - # DROP packets not matching an IPSec policy. However, any reply - # not going through IPSec would be DROPped (thanks to the rule - # in mangle:INPUT above); this is the best we can do for now. + + # DNAT all marked packets after decapsulation. iptables -A PREROUTING \! -d "$ipsec" -i $if \ -m policy --dir in --pol ipsec -j DNAT --to "${ipsec%/*}" - iptables -A POSTROUTING -s "$ipsec" -o $if -j MASQUERADE + + # Packets originating from our IPSec are SNAT'ed (MASQUERADE). + # (And null-routed later on unless there is an xfrm + # association.) + iptables -A POSTROUTING -m mark --mark $secmark -o $if -j MASQUERADE commit fi |