Patch "net: vrf: Drop conntrack data after pass through VRF device on Tx" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

net: vrf: Drop conntrack data after pass through VRF device on Tx

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
net-vrf-drop-conntrack-data-after-pass-through-vrf-device-on-tx.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: David Ahern <[email protected]>
Date: Wed, 14 Dec 2016 14:31:11 -0800
Subject: net: vrf: Drop conntrack data after pass through VRF device on Tx

From: David Ahern <[email protected]>

[ Upstream commit eb63ecc1706b3e094d0f57438b6c2067cfc299f2 ]

Locally originated traffic in a VRF fails in the presence of a POSTROUTING rule. For example,

    $ iptables -t nat -A POSTROUTING -s 11.1.1.0/24  -j MASQUERADE
    $ ping -I red -c1 11.1.1.3
    ping: Warning: source address might be selected on device other than red.
    PING 11.1.1.3 (11.1.1.3) from 11.1.1.2 red: 56(84) bytes of data.
    ping: sendmsg: Operation not permitted

Worse, the above causes random corruption resulting in a panic in random places (I have not seen a consistent backtrace).

Call nf_reset to drop the conntrack info following the pass through the VRF device. The nf_reset is needed on Tx but not Rx because of the order in which NF_HOOK's are hit: on Rx the VRF device is after the real ingress device and on Tx it is is before the real egress device. Connection tracking should be tied to the real egress device and not the VRF device.

---
 drivers/net/vrf.c |    4 ++++
 1 file changed, 4 insertions(+)

@@ -371,6 +371,8 @@ static int vrf_finish_output6(struct net
 	struct in6_addr *nexthop;
 	int ret;
 
+	nf_reset(skb);
+
 	skb->protocol = htons(ETH_P_IPV6);
 	skb->dev = dev;
 

@@ -552,6 +554,8 @@ static int vrf_finish_output(struct net
 	u32 nexthop;
 	int ret = -EINVAL;
 
+	nf_reset(skb);
+
 	/* Be paranoid, rather than too clever. */
 	if (unlikely(skb_headroom(skb) < hh_len && dev->header_ops)) {
 		struct sk_buff *skb2;

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/net-vrf-drop-conntrack-data-after-pass-through-vrf-device-on-tx.patch queue-4.9/net-ipv4-fix-multipath-selection-with-vrf.patch queue-4.9/net-ipv4-dst-for-local-input-routes-should-use-l3mdev-if-relevant.patch queue-4.9/net-vrf-add-missing-rx-counters.patch queue-4.9/net-vrf-do-not-allow-table-id-0.patch queue-4.9/net-vrf-fix-nat-within-a-vrf.patch queue-4.9/net-fix-incorrect-original-ingress-device-index-in-pktinfo.patch