diff options
| author | Guilhem Moulin <guilhem@fripost.org> | 2013-11-04 00:31:43 +0100 |
|---|---|---|
| committer | Guilhem Moulin <guilhem@fripost.org> | 2015-06-07 02:50:38 +0200 |
| commit | 67c5135625d3553dcb6f2bfc193df24c0e1ab826 (patch) | |
| tree | 21d5c3c18a1531e445cd1c0dad9ac76a358f7321 /roles/common/files/etc/network/if-up.d/ipsec | |
| parent | ad9c840c40d923e0fd1b04a57274cc2ec2e381ec (diff) | |
Prohibit binding against the IP reserved for IPSec.
Packets originating from our (non-routable) $ipsec are marked; there is
no xfrm lookup (i.e., no matching IPSec association), the packet will
retain its mark and be null routed later on, thanks to
ip rule add fwmark "$secmark" table 666 priority 666
ip route add blackhole default table 666
Diffstat (limited to 'roles/common/files/etc/network/if-up.d/ipsec')
| -rwxr-xr-x | roles/common/files/etc/network/if-up.d/ipsec | 44 |
1 files changed, 28 insertions, 16 deletions
diff --git a/roles/common/files/etc/network/if-up.d/ipsec b/roles/common/files/etc/network/if-up.d/ipsec index e21d6ea..98bf42c 100755 --- a/roles/common/files/etc/network/if-up.d/ipsec +++ b/roles/common/files/etc/network/if-up.d/ipsec @@ -11,8 +11,11 @@ set -ue PATH=/usr/sbin:/usr/bin:/sbin:/bin -if=sec0 -ip=172.16.0.1/32 +ifsec=sec0 +ipsec=172.16.0.1/32 + +# /!\ This mark much match that in /usr/local/sbin/update-firewall.sh. +secmark=0xA99 # Ignore the loopback interface and non inet4 families. [ "$IFACE" != lo -a "$ADDRFAM" = inet ] || exit 0 @@ -25,20 +28,29 @@ ip=172.16.0.1/32 "$IFACE" ] || exit 0 case "$MODE" in - start) # Don't create $if if it's already there - /bin/ip -o link show | grep -qE "^[0-9]+:\s+$if" && exit 0 - - # Create a new VLAN $IFACE on physical device $if. This is - # required otherwise charon thinks the left peer is that - # host-scoped, non-routable IP. - /bin/ip link add link "$IFACE" name "$if" type vlan id 2713 - /bin/ip address add "$ip" dev "$if" scope host - /bin/ip link set dev "$if" up + start) # Don't create $ifsec if it's already there + if ! /bin/ip -o link show | grep -qE "^[0-9]+:\s+$ifsec"; then + # Create a new VLAN $IFACE on physical device $ifsec. This is + # required otherwise charon thinks the left peer is that + # host-scoped, non-routable IP. + /bin/ip link add link "$IFACE" name "$ifsec" type vlan id 2713 + /bin/ip address add "$ipsec" dev "$ifsec" scope host + /bin/ip link set dev "$ifsec" up + fi + + # If a packet retained its mark that far, it means it has + # been SNAT'ed from $ipsec, and didn't have a xfrm + # association. Hence we nullroute it to avoid leaking data. + /bin/ip rule add fwmark "$secmark" table 666 priority 666 || true + /bin/ip route add prohibit default table 666 || true ;; - stop) # Don't create $if if it's no there - /bin/ip -o link show | grep -qE "^[0-9]+:\s+$if" || exit 0 - - # Deactivate the VLAN - /bin/ip link set dev "$if" down + stop) if /bin/ip -o link show | grep -qE "^[0-9]+:\s+$ifsec"; then + # Deactivate the VLAN + /bin/ip link set dev "$ifsec" down + fi + + # Delete the 'prohibit' rule + /bin/ip rule del fwmark "$secmark" table 666 priority 666 || true + /bin/ip route flush table 666 ;; esac |