updown: Allow IPIP traffic if IPComp was negotiated

The kernel implicitly creates an IPIP SA if an IPComp SA is installed.
This SA is used inbound for small packets that are not compressed.

Since the addresses are different (they are the tunnel addresses not
those of the tunneled traffic) additional rules are required if the
traffic selector does not cover the tunnel addresses (e.g. due to a NAT).

For SAs with multiple traffic selectors duplicate rules will get installed.

diff --git a/src/_updown/_updown.in b/src/_updown/_updown.in
index 36bf64c6a9a78199aa9d603d4a172a4b41ccc3e0..532bd243776812275cc21af7a55f098ee35c3064 100644 (file)
--- a/src/_updown/_updown.in
+++ b/src/_updown/_updown.in
@@ -414,6 +414,14 @@ up-host:iptables)
            -s $PLUTO_ME $S_MY_PORT $IPSEC_POLICY_OUT \
            -d $PLUTO_PEER_CLIENT $D_PEER_PORT -j ACCEPT
        #
+       # allow IPIP traffic because of the implicit SA created by the kernel if
+       # IPComp is used (for small inbound packets that are not compressed)
+       if [ -n "$PLUTO_IPCOMP" ]
+       then
+         iptables -I INPUT 1 -i $PLUTO_INTERFACE -p 4 \
+             -s $PLUTO_PEER -d $PLUTO_ME $IPSEC_POLICY_IN -j ACCEPT
+       fi
+       #
        # log IPsec host connection setup
        if [ $VPN_LOGGING ]
        then
@@ -438,6 +446,13 @@ down-host:iptables)
            -s $PLUTO_ME $S_MY_PORT $IPSEC_POLICY_OUT \
            -d $PLUTO_PEER_CLIENT $D_PEER_PORT -j ACCEPT
        #
+       # IPIP exception teardown
+       if [ -n "$PLUTO_IPCOMP" ]
+       then
+         iptables -D INPUT -i $PLUTO_INTERFACE -p 4 \
+             -s $PLUTO_PEER -d $PLUTO_ME $IPSEC_POLICY_IN -j ACCEPT
+       fi
+       #
        # log IPsec host connection teardown
        if [ $VPN_LOGGING ]
        then
@@ -477,6 +492,15 @@ up-client:iptables)
              -d $PLUTO_PEER_CLIENT $D_PEER_PORT $IPSEC_POLICY_OUT -j ACCEPT
        fi
        #
+       # allow IPIP traffic because of the implicit SA created by the kernel if
+       # IPComp is used (for small inbound packets that are not compressed).
+       # INPUT is correct here even for forwarded traffic.
+       if [ -n "$PLUTO_IPCOMP" ]
+       then
+         iptables -I INPUT 1 -i $PLUTO_INTERFACE -p 4 \
+             -s $PLUTO_PEER -d $PLUTO_ME $IPSEC_POLICY_IN -j ACCEPT
+       fi
+       #
        # log IPsec client connection setup
        if [ $VPN_LOGGING ]
        then
@@ -520,6 +544,13 @@ down-client:iptables)
                 $IPSEC_POLICY_OUT -j ACCEPT
        fi
        #
+       # IPIP exception teardown
+       if [ -n "$PLUTO_IPCOMP" ]
+       then
+         iptables -D INPUT -i $PLUTO_INTERFACE -p 4 \
+             -s $PLUTO_PEER -d $PLUTO_ME $IPSEC_POLICY_IN -j ACCEPT
+       fi
+       #
        # log IPsec client connection teardown
        if [ $VPN_LOGGING ]
        then