From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Cong Wang , Patrick McHardy , "David S. Miller" , Eric Dumazet Subject: [ 102/124] 8021q: fix a potential use-after-free Date: Tue, 2 Apr 2013 15:11:24 -0700 Message-Id: <20130402221115.933625351@linuxfoundation.org> In-Reply-To: <20130402221104.163133110@linuxfoundation.org> References: <20130402221104.163133110@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.8-stable review patch. If anyone has any objections, please let me know. ------------------ From: Cong Wang [ Upstream commit 4a7df340ed1bac190c124c1601bfc10cde9fb4fb ] 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. Signed-off-by: Cong Wang Cc: Patrick McHardy Cc: "David S. Miller" Acked-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/8021q/vlan.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) --- a/net/8021q/vlan.c +++ b/net/8021q/vlan.c @@ -86,13 +86,6 @@ void unregister_vlan_dev(struct net_devi 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_GVRP) @@ -108,6 +101,13 @@ void unregister_vlan_dev(struct net_devi if (grp->nr_vlan_devs == 0) 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); }