This is a note to let you know that I've just added the patch titled
l2tp: protect tunnel->del_work by ref_count
to the 4.2-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:
l2tp-protect-tunnel-del_work-by-ref_count.patch
and it can be found in the queue-4.2 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Thu Oct 22 17:25:24 PDT 2015
From: Alexander Couzens <lynxis@xxxxxxx>
Date: Mon, 28 Sep 2015 11:32:42 +0200
Subject: l2tp: protect tunnel->del_work by ref_count
From: Alexander Couzens <lynxis@xxxxxxx>
[ Upstream commit 06a15f51cf3618e32a73871ee6a547ef7fd902b5 ]
There is a small chance that tunnel_free() is called before tunnel->del_work scheduled
resulting in a zero pointer dereference.
Signed-off-by: Alexander Couzens <lynxis@xxxxxxx>
Acked-by: James Chapman <jchapman@xxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/l2tp/l2tp_core.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
--- a/net/l2tp/l2tp_core.c
+++ b/net/l2tp/l2tp_core.c
@@ -1319,7 +1319,7 @@ static void l2tp_tunnel_del_work(struct
tunnel = container_of(work, struct l2tp_tunnel, del_work);
sk = l2tp_tunnel_sock_lookup(tunnel);
if (!sk)
- return;
+ goto out;
sock = sk->sk_socket;
@@ -1341,6 +1341,8 @@ static void l2tp_tunnel_del_work(struct
}
l2tp_tunnel_sock_put(sk);
+out:
+ l2tp_tunnel_dec_refcount(tunnel);
}
/* Create a socket for the tunnel, if one isn't set up by
@@ -1636,8 +1638,13 @@ EXPORT_SYMBOL_GPL(l2tp_tunnel_create);
*/
int l2tp_tunnel_delete(struct l2tp_tunnel *tunnel)
{
+ l2tp_tunnel_inc_refcount(tunnel);
l2tp_tunnel_closeall(tunnel);
- return (false == queue_work(l2tp_wq, &tunnel->del_work));
+ if (false == queue_work(l2tp_wq, &tunnel->del_work)) {
+ l2tp_tunnel_dec_refcount(tunnel);
+ return 1;
+ }
+ return 0;
}
EXPORT_SYMBOL_GPL(l2tp_tunnel_delete);
Patches currently in stable-queue which might be from lynxis@xxxxxxx are
queue-4.2/l2tp-protect-tunnel-del_work-by-ref_count.patch
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