[PATCH 062/102] 8021q: fix a potential use-after-free
From: Luis Henriques
Date: Mon Apr 08 2013 - 06:07:53 EST
126.96.36.199 -stable review patch. If anyone has any objections, please let me know.
From: Cong Wang <amwang@xxxxxxxxxx>
commit 4a7df340ed1bac190c124c1601bfc10cde9fb4fb upstream.
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@xxxxxxxxx>
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Signed-off-by: Cong Wang <amwang@xxxxxxxxxx>
Acked-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
net/8021q/vlan.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/net/8021q/vlan.c b/net/8021q/vlan.c
index 9096bcb..8bdc56d 100644
@@ -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);
if (vlan->flags & VLAN_FLAG_GVRP)
@@ -108,6 +101,13 @@ void unregister_vlan_dev(struct net_device *dev, struct list_head *head)
if (grp->nr_vlan_devs == 0)
+ /* 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 */
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