Subject: [net-next PATCH] qdisc: validate frames going through the direct_xmit path

From: Jesper Dangaard Brouer <[email-masked]>
Date: Wed, 03 Sep 2014 13:48:41 +0200

In commit 50cbe9ab5f8d ("net: Validate xmit SKBs right when we pull them
out of the qdisc") the validation code was moved out of dev_hard_start_xmit
and into dequeue_skb. However this overlooked the fact that we do not
always enqueue the skb onto a qdisc, if qdisc have flag TCQ_F_CAN_BYPASS.

As a result Alex was seeing issues trying to connect to a vhost_net interface
after this patch was applied.

Added a call to validate_xmit_skb in __dev_xmit_skb(), in the code path
for qdiscs with TCQ_F_CAN_BYPASS flag.

Fixes:  50cbe9ab5f8d ("net: Validate xmit SKBs right when we pull them out of the qdisc")
Signed-off-by: Alexander Duyck <[email-masked]>
Signed-off-by: Jesper Dangaard Brouer <[email-masked]>
---

 net/core/dev.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index 3774afc..5bbac90 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2739,7 +2739,8 @@ static inline int __dev_xmit_skb(struct sk_buff *skb, struct Qdisc *q,
 
 		qdisc_bstats_update(q, skb);
 
-		if (sch_direct_xmit(skb, q, dev, txq, root_lock)) {
+		skb = validate_xmit_skb(skb, dev);
+		if (skb && sch_direct_xmit(skb, q, dev, txq, root_lock)) {
 			if (unlikely(contended)) {
 				spin_unlock(&q->busylock);
 				contended = false;