From: Guillaume Nault <g.nault@alphalink.fr>
Date: Fri, 25 Aug 2017 14:51:42 +0000 (+0200)
Subject: l2tp: hold tunnel while processing genl delete command
X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=bb0a32ce4389e17e47e198d2cddaf141561581ad;p=openwrt%2Fstaging%2Fblogic.git

l2tp: hold tunnel while processing genl delete command

l2tp_nl_cmd_tunnel_delete() needs to take a reference on the tunnel, to
prevent it from being concurrently freed by l2tp_tunnel_destruct().

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>
---

diff --git a/net/l2tp/l2tp_netlink.c b/net/l2tp/l2tp_netlink.c
index 27ee94b5c189..808966550620 100644
--- a/net/l2tp/l2tp_netlink.c
+++ b/net/l2tp/l2tp_netlink.c
@@ -273,8 +273,8 @@ static int l2tp_nl_cmd_tunnel_delete(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;
 	}
@@ -284,6 +284,8 @@ static int l2tp_nl_cmd_tunnel_delete(struct sk_buff *skb, struct genl_info *info
 
 	(void) l2tp_tunnel_delete(tunnel);
 
+	l2tp_tunnel_dec_refcount(tunnel);
+
 out:
 	return ret;
 }