From: Cong Wang <xiyou.wangcong@gmail.com>

Date: Tue, 9 Jan 2018 13:40:41 -0800

Subject: 8021q: fix a memory leak for VLAN 0 device

Git-commit: 78bbb15f2239bc8e663aa20bbe1987c91a0b75f6

Patch-mainline: v4.15-rc8

References: networking-stable-18_01_12

A vlan device with vid 0 is allow to creat by not able to be fully

cleaned up by unregister_vlan_dev() which checks for vlan_id!=0.

Also, VLAN 0 is probably not a valid number and it is kinda

"reserved" for HW accelerating devices, but it is probably too

late to reject it from creation even if makes sense. Instead,

just remove the check in unregister_vlan_dev().

Reported-by: Dmitry Vyukov <dvyukov@google.com>

Fixes: ad1afb003939 ("vlan_dev: VLAN 0 should be treated as "no vlan tag" (802.1p packet)")

Cc: Vlad Yasevich <vyasevich@gmail.com>

Cc: Ben Hutchings <ben.hutchings@codethink.co.uk>

Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>

Signed-off-by: David S. Miller <davem@davemloft.net>

Signed-off-by: Jiri Slaby <jslaby@suse.cz>

---

 net/8021q/vlan.c |    7 +------

 1 file changed, 1 insertion(+), 6 deletions(-)

--- a/net/8021q/vlan.c

+++ b/net/8021q/vlan.c

@@ -111,12 +111,7 @@ void unregister_vlan_dev(struct net_devi

 		vlan_gvrp_uninit_applicant(real_dev);

 	}

-	/* Take it out of our own structures, but be sure to interlock with

-	 * HW accelerating devices or SW vlan input packet processing if

-	 * VLAN is not 0 (leave it there for 802.1p).

-	 */

-	if (vlan_id)

-		vlan_vid_del(real_dev, vlan->vlan_proto, vlan_id);

+	vlan_vid_del(real_dev, vlan->vlan_proto, vlan_id);

 	/* Get rid of the vlan's reference to real_dev */

 	dev_put(real_dev);