lkml.org 
[lkml]   [2013]   [Apr]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Date
Subject[56/74] 8021q: fix a potential use-after-free
3.2.43-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Cong Wang <amwang@redhat.com>

[ 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.

Cc: Patrick McHardy <kaber@trash.net>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Cong Wang <amwang@redhat.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
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 5471628..963f285 100644
--- a/net/8021q/vlan.c
+++ b/net/8021q/vlan.c
@@ -110,13 +110,6 @@ void unregister_vlan_dev(struct net_device *dev, struct list_head *head)
grp = rtnl_dereference(real_dev->vlgrp);
BUG_ON(!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 && (real_dev->features & NETIF_F_HW_VLAN_FILTER))
- ops->ndo_vlan_rx_kill_vid(real_dev, vlan_id);
-
grp->nr_vlans--;

if (vlan->flags & VLAN_FLAG_GVRP)
@@ -139,6 +132,13 @@ void unregister_vlan_dev(struct net_device *dev, struct list_head *head)
call_rcu(&grp->rcu, vlan_rcu_free);
}

+ /* 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 && (real_dev->features & NETIF_F_HW_VLAN_FILTER))
+ ops->ndo_vlan_rx_kill_vid(real_dev, vlan_id);
+
/* Get rid of the vlan's reference to real_dev */
dev_put(real_dev);
}


\
 
 \ /
  Last update: 2013-04-08 02:01    [W:0.525 / U:0.616 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site