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l2tp: protect tunnel->del_work by ref_count 

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@fe80.eu>
Acked-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
hifive-unleashed-5.1
Alexander Couzens 2015-09-28 11:32:42 +02:00 committed by David S. Miller
parent 661dfc65f7
commit 06a15f51cf
1 changed files with 9 additions and 2 deletions
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11
net/l2tp/l2tp_core.c
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@ -1319,7 +1319,7 @@ static void l2tp_tunnel_del_work(struct work_struct *work)
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 work_struct *work)
}
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);