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* [PATCH net] vrf: Fix use after free and double free in vrf_finish_output
@ 2018-03-29 19:49 David Ahern
  2018-03-30 18:21 ` David Miller
  0 siblings, 1 reply; 2+ messages in thread
From: David Ahern @ 2018-03-29 19:49 UTC (permalink / raw)
  To: netdev; +Cc: David Ahern, Miguel Fadon Perlines

Miguel reported an skb use after free / double free in vrf_finish_output
when neigh_output returns an error. The vrf driver should return after
the call to neigh_output as it takes over the skb on error path as well.

Patch is a simplified version of Miguel's patch which was written for 4.9,
and updated to top of tree.

Fixes: 8f58336d3f78a ("net: Add ethernet header for pass through VRF device")
Signed-off-by: Miguel Fadon Perlines <mfadon@teldat•com>
Signed-off-by: David Ahern <dsahern@gmail•com>
---
 drivers/net/vrf.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/net/vrf.c b/drivers/net/vrf.c
index 139c61c8244a..ac40924fe437 100644
--- a/drivers/net/vrf.c
+++ b/drivers/net/vrf.c
@@ -578,12 +578,13 @@ static int vrf_finish_output(struct net *net, struct sock *sk, struct sk_buff *s
 	if (!IS_ERR(neigh)) {
 		sock_confirm_neigh(skb, neigh);
 		ret = neigh_output(neigh, skb);
+		rcu_read_unlock_bh();
+		return ret;
 	}
 
 	rcu_read_unlock_bh();
 err:
-	if (unlikely(ret < 0))
-		vrf_tx_error(skb->dev, skb);
+	vrf_tx_error(skb->dev, skb);
 	return ret;
 }
 
-- 
2.11.0

^ permalink raw reply related	[flat|nested] 2+ messages in thread

* Re: [PATCH net] vrf: Fix use after free and double free in vrf_finish_output
  2018-03-29 19:49 [PATCH net] vrf: Fix use after free and double free in vrf_finish_output David Ahern
@ 2018-03-30 18:21 ` David Miller
  0 siblings, 0 replies; 2+ messages in thread
From: David Miller @ 2018-03-30 18:21 UTC (permalink / raw)
  To: dsahern; +Cc: netdev, mfadon

From: David Ahern <dsahern@gmail•com>
Date: Thu, 29 Mar 2018 12:49:52 -0700

> Miguel reported an skb use after free / double free in vrf_finish_output
> when neigh_output returns an error. The vrf driver should return after
> the call to neigh_output as it takes over the skb on error path as well.
> 
> Patch is a simplified version of Miguel's patch which was written for 4.9,
> and updated to top of tree.
> 
> Fixes: 8f58336d3f78a ("net: Add ethernet header for pass through VRF device")
> Signed-off-by: Miguel Fadon Perlines <mfadon@teldat•com>
> Signed-off-by: David Ahern <dsahern@gmail•com>

Applied and queued up for -stable, thanks David.

^ permalink raw reply	[flat|nested] 2+ messages in thread

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