ipv4/ip_vti.c: VTI fix post-decryption forwarding

[ Upstream commit b2942004fb5c9f3304b77e187b8a1977b3626c9b ]

With the latest kernel there are two things that must be done post decryption
 so that the packet are forwarded.
 1. Remove the mark from the packet. This will cause the packet to not match
 the ipsec-policy again. However doing this causes the post-decryption check to
 fail also and the packet will get dropped. (cat /proc/net/xfrm_stat).
 2. Remove the sp association in the skbuff so that no policy check is done on
 the packet for VTI tunnels.

Due to #2 above we must now do a security-policy check in the vti rcv path
prior to resetting the mark in the skbuff.

Signed-off-by: Saurabh Mohan <saurabh.mohan@vyatta.com>
Reported-by: Ruben Herold <ruben@puettmann.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/ipv4/ip_vti.c b/net/ipv4/ip_vti.c
index 3511ffba7bd41088cd95d677f5c43dab947d9bf2..bf89b21d22d0f6893e516c77fbe1e1ac2a8b17be 100644 (file)
--- a/net/ipv4/ip_vti.c
+++ b/net/ipv4/ip_vti.c
@@ -341,12 +341,17 @@ static int vti_rcv(struct sk_buff *skb)
        if (tunnel != NULL) {
                struct pcpu_tstats *tstats;
 
+               if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
+                       return -1;
+
                tstats = this_cpu_ptr(tunnel->dev->tstats);
                u64_stats_update_begin(&tstats->syncp);
                tstats->rx_packets++;
                tstats->rx_bytes += skb->len;
                u64_stats_update_end(&tstats->syncp);
 
+               skb->mark = 0;
+               secpath_reset(skb);
                skb->dev = tunnel->dev;
                rcu_read_unlock();
                return 1;