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-rwxr-xr-xroles/common/files/usr/local/sbin/update-firewall.sh29
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