[Bridge] bridge: fix use-after-free in br_cleanup_bridges()

[Stephen Hemminger]

On Wed, 02 Jul 2008 15:04:14 +0200
Patrick McHardy <kaber at trash.net> wrote:

> commit 96f1dd78dad10d61bdd487edadea6adda5425e4c
> Author: Patrick McHardy <kaber at trash.net>
> 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 <kaber at trash.net>

Acked-by: Stephen Hemminger <shemminger at vyatta.com>