netdev - [PATCH] route: put lwstate before freeing dst to avoid use after free

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Date:	Tue, 25 Aug 2015 14:25:14 -0400
From:	Sasha Levin <sasha.levin@...cle.com>
To:	davem@...emloft.net
Cc:	jbenc@...hat.com, roopa@...ulusnetworks.com, tgraf@...g.ch,
	netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
	Sasha Levin <sasha.levin@...cle.com>
Subject: [PATCH] route: put lwstate before freeing dst to avoid use after free

Commit 61adedf3 ("route: move lwtunnel state to dst_entry") is trying to
release lwstate after getting rid of dst, which causes a use-after-free
trying to access dst->lwstate.

Fixes: 61adedf3 ("route: move lwtunnel state to dst_entry")
Signed-off-by: Sasha Levin <sasha.levin@...cle.com>
---
 net/core/dst.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/core/dst.c b/net/core/dst.c
index 50dcdbb..477035e 100644
--- a/net/core/dst.c
+++ b/net/core/dst.c
@@ -262,11 +262,12 @@ again:
 	if (dst->dev)
 		dev_put(dst->dev);
 
+	lwtstate_put(dst->lwtstate);
+
 	if (dst->flags & DST_METADATA)
 		kfree(dst);
 	else
 		kmem_cache_free(dst->ops->kmem_cachep, dst);
-	lwtstate_put(dst->lwtstate);
 
 	dst = child;
 	if (dst) {
-- 
1.7.10.4

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