From: Patrick McHardy Date: Thu, 3 Jul 2008 10:53:42 +0000 (-0700) Subject: bridge: fix use-after-free in br_cleanup_bridges() X-Git-Tag: v2.6.26~51^2~11 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ab1b20467cd2214ad89a95d007047cd2a6b5bf5d;p=linux-2.6 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 Acked-by: Stephen Hemminger Signed-off-by: David S. Miller --- diff --git a/net/bridge/br_if.c b/net/bridge/br_if.c index c2397f503b..f38cc5317b 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(); }