From: Guillaume Nault <g.nault@alphalink.fr>
Date: Fri, 25 Aug 2017 16:22:17 +0200
Subject: l2tp: initialise session's refcount before making it reachable
Patch-mainline: v4.13
Git-commit: 9ee369a405c57613d7c83a3967780c3e30c52ecc
References: bsc#1076830
Sessions must be fully initialised before calling
l2tp_session_add_to_tunnel(). Otherwise, there's a short time frame
where partially initialised sessions can be accessed by external users.
Fixes: dbdbc73b4478 ("l2tp: fix duplicate session creation")
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Michal Kubecek <mkubecek@suse.cz>
---
net/l2tp/l2tp_core.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c
index a2a8ad8c5778..a7d56be8a635 100644
--- a/net/l2tp/l2tp_core.c
+++ b/net/l2tp/l2tp_core.c
@@ -1818,6 +1818,8 @@ struct l2tp_session *l2tp_session_create(int priv_size, struct l2tp_tunnel *tunn
l2tp_session_set_header_len(session, tunnel->version);
+ l2tp_session_inc_refcount(session);
+
err = l2tp_session_add_to_tunnel(tunnel, session);
if (err) {
kfree(session);
@@ -1825,10 +1827,6 @@ struct l2tp_session *l2tp_session_create(int priv_size, struct l2tp_tunnel *tunn
return ERR_PTR(err);
}
- /* Bump the reference count. The session context is deleted
- * only when this drops to zero.
- */
- l2tp_session_inc_refcount(session);
l2tp_tunnel_inc_refcount(tunnel);
/* Ensure tunnel socket isn't deleted */
--
2.16.1