From ab1b20467cd2214ad89a95d007047cd2a6b5bf5d Mon Sep 17 00:00:00 2001 From: Patrick McHardy Date: Thu, 3 Jul 2008 03:53:42 -0700 Subject: [PATCH] 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 --- net/bridge/br_if.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/net/bridge/br_if.c b/net/bridge/br_if.c index c2397f503b0f..f38cc5317b88 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(); } -- 2.30.2