l2tp: hold tunnel while handling genl tunnel updates
authorGuillaume Nault <g.nault@alphalink.fr>
Fri, 25 Aug 2017 14:51:42 +0000 (16:51 +0200)
committerDavid S. Miller <davem@davemloft.net>
Mon, 28 Aug 2017 18:34:58 +0000 (11:34 -0700)
We need to make sure the tunnel is not going to be destroyed by
l2tp_tunnel_destruct() concurrently.

Fixes: 309795f4bec2 ("l2tp: Add netlink control API for L2TP")
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/l2tp/l2tp_netlink.c

index 8089665..d61e75b 100644 (file)
@@ -303,8 +303,8 @@ static int l2tp_nl_cmd_tunnel_modify(struct sk_buff *skb, struct genl_info *info
        }
        tunnel_id = nla_get_u32(info->attrs[L2TP_ATTR_CONN_ID]);
 
-       tunnel = l2tp_tunnel_find(net, tunnel_id);
-       if (tunnel == NULL) {
+       tunnel = l2tp_tunnel_get(net, tunnel_id);
+       if (!tunnel) {
                ret = -ENODEV;
                goto out;
        }
@@ -315,6 +315,8 @@ static int l2tp_nl_cmd_tunnel_modify(struct sk_buff *skb, struct genl_info *info
        ret = l2tp_tunnel_notify(&l2tp_nl_family, info,
                                 tunnel, L2TP_CMD_TUNNEL_MODIFY);
 
+       l2tp_tunnel_dec_refcount(tunnel);
+
 out:
        return ret;
 }