From mboxrd@z Thu Jan 1 00:00:00 1970 From: Patrick McHardy Subject: bridge: fix use-after-free in br_cleanup_bridges() Date: Wed, 02 Jul 2008 15:04:14 +0200 Message-ID: <486B7CCE.2@trash.net> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="------------030601090400060801020405" Cc: Stephen Hemminger , Linux Netdev List , bridge@lists.linux-foundation.org To: "David S. Miller" Return-path: Received: from stinky.trash.net ([213.144.137.162]:36917 "EHLO stinky.trash.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752924AbYGBNES (ORCPT ); Wed, 2 Jul 2008 09:04:18 -0400 Sender: netdev-owner@vger.kernel.org List-ID: This is a multi-part message in MIME format. --------------030601090400060801020405 Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit --------------030601090400060801020405 Content-Type: text/plain; name="x" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="x" commit 96f1dd78dad10d61bdd487edadea6adda5425e4c Author: Patrick McHardy Date: Wed Jul 2 15:02:23 2008 +0200 bridge: fix use-after-free in br_cleanup_bridges() Unregistering a bridge device may cause virtual devices stacked on the bridge, like vlan or macvlan devices, to be unregistered as well. br_cleanup_bridges() uses for_each_netdev_safe() to iterate over all devices during cleanup. This is not enough however, if one of the additionally unregistered devices is next in the list to the bridge device, it will get freed as well and the iteration continues on the freed element. Restart iteration after each bridge device removal from the beginning to fix this, similar to what rtnl_link_unregister() does. Signed-off-by: Patrick McHardy diff --git a/net/bridge/br_if.c b/net/bridge/br_if.c index c2397f5..f38cc53 100644 --- a/net/bridge/br_if.c +++ b/net/bridge/br_if.c @@ -442,12 +442,16 @@ int br_del_if(struct net_bridge *br, struct net_device *dev) void __exit br_cleanup_bridges(void) { - struct net_device *dev, *nxt; + struct net_device *dev; rtnl_lock(); - for_each_netdev_safe(&init_net, dev, nxt) - if (dev->priv_flags & IFF_EBRIDGE) +restart: + for_each_netdev(&init_net, dev) { + if (dev->priv_flags & IFF_EBRIDGE) { del_br(dev->priv); + goto restart; + } + } rtnl_unlock(); } --------------030601090400060801020405--