From mboxrd@z Thu Jan 1 00:00:00 1970 From: Cong Wang Subject: [PATCH net-next] 8021q: fix a potential use-after-free Date: Sat, 23 Mar 2013 13:14:07 +0800 Message-ID: <1364015648-4195-1-git-send-email-amwang@redhat.com> References: <1363938600-26129-1-git-send-email-amwang@redhat.com> Cc: Patrick McHardy , "David S. Miller" , Cong Wang To: netdev@vger.kernel.org Return-path: Received: from mx1.redhat.com ([209.132.183.28]:26155 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755536Ab3CWFOX (ORCPT ); Sat, 23 Mar 2013 01:14:23 -0400 In-Reply-To: <1363938600-26129-1-git-send-email-amwang@redhat.com> Sender: netdev-owner@vger.kernel.org List-ID: From: Cong Wang 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 Cc: "David S. Miller" Signed-off-by: Cong Wang --- net/8021q/vlan.c | 14 +++++++------- 1 files changed, 7 insertions(+), 7 deletions(-) diff --git a/net/8021q/vlan.c b/net/8021q/vlan.c index a187144..85addcd 100644 --- a/net/8021q/vlan.c +++ b/net/8021q/vlan.c @@ -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); } -- 1.7.7.6