[PATCH] net: check queue_index from sock is valid for device

[PATCH] net: check queue_index from sock is valid for device

[Tom Herbert]

In dev_pick_tx recompute the queue index if the value stored in the
socket is greater than or equal to the number of real queues for the
device.  The saved index in the sock structure is not guaranteed to
be appropriate for the egress device (this could happen on a route
change or in presence of tunnelling).  The result of the queue index
being bad would be to return a bogus queue (crash could prersumably
follow).

Signed-off-by: Tom Herbert <therbert@google.com>
---
 net/core/dev.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index 78b5a89..dc2a307 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2135,7 +2135,7 @@ static struct netdev_queue *dev_pick_tx(struct net_device *dev,
 	} else {
 		struct sock *sk = skb->sk;
 		queue_index = sk_tx_queue_get(sk);
-		if (queue_index < 0) {
+		if (queue_index < 0 || queue_index >= dev->real_num_tx_queues) {
 
 			queue_index = 0;
 			if (dev->real_num_tx_queues > 1)
-- 
1.7.3.1

Re: [PATCH] net: check queue_index from sock is valid for device

[David Miller]

From: Tom Herbert <therbert@google.com>
Date: Mon, 1 Nov 2010 12:53:32 -0700 (PDT)

> In dev_pick_tx recompute the queue index if the value stored in the
> socket is greater than or equal to the number of real queues for the
> device.  The saved index in the sock structure is not guaranteed to
> be appropriate for the egress device (this could happen on a route
> change or in presence of tunnelling).  The result of the queue index
> being bad would be to return a bogus queue (crash could prersumably
> follow).
> 
> Signed-off-by: Tom Herbert <therbert@google.com>

Looks good, applied, thanks Tom.