xfrm: Add xfrm_tunnel_skb_cb to the skb common buffer

IPsec vti_rcv needs to remind the tunnel pointer to
check it later at the vti_rcv_cb callback. So add
this pointer to the IPsec common buffer, initialize
it and check it to avoid transport state matching of
a tunneled packet.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/net/xfrm/xfrm_input.c b/net/xfrm/xfrm_input.c
index 99e3a9e5285e..4218164f4f5e 100644
--- a/net/xfrm/xfrm_input.c
+++ b/net/xfrm/xfrm_input.c
@@ -163,6 +163,11 @@ int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
 
                 skb->sp->xvec[skb->sp->len++] = x;
 
+                if (xfrm_tunnel_check(skb, x, family)) {
+                        XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEMODEERROR);
+                        goto drop;
+                }
+
                 spin_lock(&x->lock);
                 if (unlikely(x->km.state == XFRM_STATE_ACQ)) {
                         XFRM_INC_STATS(net, LINUX_MIB_XFRMACQUIREERROR);