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Commit 4a7df340 authored by Cong Wang's avatar Cong Wang Committed by David S. Miller
Browse files

8021q: fix a potential use-after-free 



vlan_vid_del() could possibly free ->vlan_info after a RCU grace
period, however, we may still refer to the freed memory area
by 'grp' pointer. Found by code inspection.

This patch moves vlan_vid_del() as behind as possible.

Cc: Patrick McHardy <kaber@trash.net>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: default avatarCong Wang <amwang@redhat.com>
Acked-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 9979a55a

net/8021q/vlan.c

+7 −7
Original line number Diff line number Diff line
@@ -86,13 +86,6 @@ void unregister_vlan_dev(struct net_device *dev, struct list_head *head) 


	grp = &vlan_info->grp;



	/* 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_id);



	grp->nr_vlan_devs--;



	if (vlan->flags & VLAN_FLAG_MVRP)
@@ -114,6 +107,13 @@ void unregister_vlan_dev(struct net_device *dev, struct list_head *head) 
		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_id);



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

	dev_put(real_dev);

}