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Commit 06a15f51 authored by Alexander Couzens's avatar Alexander Couzens Committed by David S. Miller
Browse files

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: default avatarAlexander Couzens <lynxis@fe80.eu>
Acked-by: default avatarJames Chapman <jchapman@katalix.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 661dfc65

net/l2tp/l2tp_core.c

+9 −2
Original line number Original line Diff line number Diff line
@@ -1319,7 +1319,7 @@ static void l2tp_tunnel_del_work(struct work_struct *work) 
	tunnel = container_of(work, struct l2tp_tunnel, del_work);

	tunnel = container_of(work, struct l2tp_tunnel, del_work);

	sk = l2tp_tunnel_sock_lookup(tunnel);

	sk = l2tp_tunnel_sock_lookup(tunnel);

	if (!sk)

	if (!sk)

		return;

		goto out;





	sock = sk->sk_socket;

	sock = sk->sk_socket;
@@ -1341,6 +1341,8 @@ static void l2tp_tunnel_del_work(struct work_struct *work) 
	}

	}





	l2tp_tunnel_sock_put(sk);

	l2tp_tunnel_sock_put(sk);

out:

	l2tp_tunnel_dec_refcount(tunnel);

}

}





/* Create a socket for the tunnel, if one isn't set up by

/* 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)

int l2tp_tunnel_delete(struct l2tp_tunnel *tunnel)

{

{

	l2tp_tunnel_inc_refcount(tunnel);

	l2tp_tunnel_closeall(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);

EXPORT_SYMBOL_GPL(l2tp_tunnel_delete);