1 files changed, 28 insertions, 13 deletions

diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c
index 90165a6874bc..ee485df73ccd 100644
--- a/net/l2tp/l2tp_core.c
+++ b/net/l2tp/l2tp_core.c
@@ -329,13 +329,21 @@ static int l2tp_session_add_to_tunnel(struct l2tp_tunnel *tunnel,
 	struct hlist_head *g_head;
 	struct hlist_head *head;
 	struct l2tp_net *pn;
+	int err;
 
 	head = l2tp_session_id_hash(tunnel, session->session_id);
 
 	write_lock_bh(&tunnel->hlist_lock);
+	if (!tunnel->acpt_newsess) {
+		err = -ENODEV;
+		goto err_tlock;
+	}
+
 	hlist_for_each_entry(session_walk, head, hlist)
-		if (session_walk->session_id == session->session_id)
-			goto exist;
+		if (session_walk->session_id == session->session_id) {
+			err = -EEXIST;
+			goto err_tlock;
+		}
 
 	if (tunnel->version == L2TP_HDR_VER_3) {
 		pn = l2tp_pernet(tunnel->l2tp_net);
@@ -343,12 +351,21 @@ static int l2tp_session_add_to_tunnel(struct l2tp_tunnel *tunnel,
 						session->session_id);
 
 		spin_lock_bh(&pn->l2tp_session_hlist_lock);
+
 		hlist_for_each_entry(session_walk, g_head, global_hlist)
-			if (session_walk->session_id == session->session_id)
-				goto exist_glob;
+			if (session_walk->session_id == session->session_id) {
+				err = -EEXIST;
+				goto err_tlock_pnlock;
+			}
 
+		l2tp_tunnel_inc_refcount(tunnel);
+		sock_hold(tunnel->sock);
 		hlist_add_head_rcu(&session->global_hlist, g_head);
+
 		spin_unlock_bh(&pn->l2tp_session_hlist_lock);
+	} else {
+		l2tp_tunnel_inc_refcount(tunnel);
+		sock_hold(tunnel->sock);
 	}
 
 	hlist_add_head(&session->hlist, head);
@@ -356,12 +373,12 @@ static int l2tp_session_add_to_tunnel(struct l2tp_tunnel *tunnel,
 
 	return 0;
 
-exist_glob:
+err_tlock_pnlock:
 	spin_unlock_bh(&pn->l2tp_session_hlist_lock);
-exist:
+err_tlock:
 	write_unlock_bh(&tunnel->hlist_lock);
 
-	return -EEXIST;
+	return err;
 }
 
 /* Lookup a tunnel by id
@@ -1251,7 +1268,6 @@ static void l2tp_tunnel_destruct(struct sock *sk)
 	/* Remove hooks into tunnel socket */
 	sk->sk_destruct = tunnel->old_sk_destruct;
 	sk->sk_user_data = NULL;
-	tunnel->sock = NULL;
 
 	/* Remove the tunnel struct from the tunnel list */
 	pn = l2tp_pernet(tunnel->l2tp_net);
@@ -1261,6 +1277,8 @@ static void l2tp_tunnel_destruct(struct sock *sk)
 	atomic_dec(&l2tp_tunnel_count);
 
 	l2tp_tunnel_closeall(tunnel);
+
+	tunnel->sock = NULL;
 	l2tp_tunnel_dec_refcount(tunnel);
 
 	/* Call the original destructor */
@@ -1285,6 +1303,7 @@ void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel)
 		  tunnel->name);
 
 	write_lock_bh(&tunnel->hlist_lock);
+	tunnel->acpt_newsess = false;
 	for (hash = 0; hash < L2TP_HASH_SIZE; hash++) {
 again:
 		hlist_for_each_safe(walk, tmp, &tunnel->session_hlist[hash]) {
@@ -1581,6 +1600,7 @@ int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id, u32
 	tunnel->magic = L2TP_TUNNEL_MAGIC;
 	sprintf(&tunnel->name[0], "tunl %u", tunnel_id);
 	rwlock_init(&tunnel->hlist_lock);
+	tunnel->acpt_newsess = true;
 
 	/* The net we belong to */
 	tunnel->l2tp_net = net;
@@ -1829,11 +1849,6 @@ struct l2tp_session *l2tp_session_create(int priv_size, struct l2tp_tunnel *tunn
 			return ERR_PTR(err);
 		}
 
-		l2tp_tunnel_inc_refcount(tunnel);
-
-		/* Ensure tunnel socket isn't deleted */
-		sock_hold(tunnel->sock);
-
 		/* Ignore management session in session count value */
 		if (session->session_id != 0)
 			atomic_inc(&l2tp_session_count);