With an IPsec tunnel without dedicated interface, netfilter sees locally
generated packets twice as they exit the physical interface: Once as "the
inner packet" with IPsec context attached and once as the encrypted
(ESP) packet.
With xfrm_interface, the inner packet did not traverse NF_INET_LOCAL_OUT
hook anymore, making it impossible to match on both inner header values
and associated IPsec data from that hook.
Fix this by looping packets transmitted from xfrm_interface through
NF_INET_LOCAL_OUT before passing them on to dst_output(), which makes
behaviour consistent again from netfilter's point of view.
Fixes: f203b76d78092 ("xfrm: Add virtual xfrm interfaces")
Signed-off-by: Phil Sutter <phil@xxxxxx>
---
net/xfrm/xfrm_interface.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/xfrm/xfrm_interface.c b/net/xfrm/xfrm_interface.c
index aa4cdcf69d471..24af61c95b4d4 100644
--- a/net/xfrm/xfrm_interface.c
+++ b/net/xfrm/xfrm_interface.c
@@ -317,7 +317,8 @@ xfrmi_xmit2(struct sk_buff *skb, struct net_device *dev, struct flowi *fl)
skb_dst_set(skb, dst);
skb->dev = tdev;
- err = dst_output(xi->net, skb->sk, skb);
+ err = NF_HOOK(skb_dst(skb)->ops->family, NF_INET_LOCAL_OUT, xi->net,
+ skb->sk, skb, NULL, skb_dst(skb)->dev, dst_output);
if (net_xmit_eval(err) == 0) {
struct pcpu_sw_netstats *tstats = this_cpu_ptr(dev->tstats);
--
2.28.0
