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authorXin Long <lucien.xin@gmail.com>2018-11-13 01:08:25 +0800
committerDavid S. Miller <davem@davemloft.net>2018-11-14 22:49:31 -0800
commitf8504f4ca0a0e9f84546ef86e00b24d2ea9a0bd2 (patch)
treec49fba072a648b622d149a1d47d2379a2d2cb439 /net/l2tp
parent007b656851ed7f94ba0fa358ac3e5d7705da6846 (diff)
l2tp: fix a sock refcnt leak in l2tp_tunnel_register
This issue happens when trying to add an existent tunnel. It doesn't call sock_put() before returning -EEXIST to release the sock refcnt that was held by calling sock_hold() before the existence check. This patch is to fix it by holding the sock after doing the existence check. Fixes: f6cd651b056f ("l2tp: fix race in duplicate tunnel detection") Reported-by: Jianlin Shi <jishi@redhat.com> Signed-off-by: Xin Long <lucien.xin@gmail.com> Reviewed-by: Guillaume Nault <g.nault@alphalink.fr> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/l2tp')
-rw-r--r--net/l2tp/l2tp_core.c9
1 files changed, 4 insertions, 5 deletions
diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c
index 82cdf9020b53..26f1d435696a 100644
--- a/net/l2tp/l2tp_core.c
+++ b/net/l2tp/l2tp_core.c
@@ -1490,12 +1490,7 @@ int l2tp_tunnel_register(struct l2tp_tunnel *tunnel, struct net *net,
goto err_sock;
}
- sk = sock->sk;
-
- sock_hold(sk);
- tunnel->sock = sk;
tunnel->l2tp_net = net;
-
pn = l2tp_pernet(net);
spin_lock_bh(&pn->l2tp_tunnel_list_lock);
@@ -1510,6 +1505,10 @@ int l2tp_tunnel_register(struct l2tp_tunnel *tunnel, struct net *net,
list_add_rcu(&tunnel->list, &pn->l2tp_tunnel_list);
spin_unlock_bh(&pn->l2tp_tunnel_list_lock);
+ sk = sock->sk;
+ sock_hold(sk);
+ tunnel->sock = sk;
+
if (tunnel->encap == L2TP_ENCAPTYPE_UDP) {
struct udp_tunnel_sock_cfg udp_cfg = {
.sk_user_data = tunnel,