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>
diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c
index f6b090d..afca2eb 100644
--- a/net/l2tp/l2tp_core.c
+++ b/net/l2tp/l2tp_core.c
@@ -1319,7 +1319,7 @@
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 @@
}
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 @@
*/
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);