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authorPatrick McHardy <kaber@trash.net>2008-01-20 17:25:14 -0800
committerDavid S. Miller <davem@davemloft.net>2008-01-20 20:31:45 -0800
commit68365458a4252fa993b91a00f7a0b18fed399f0d (patch)
tree824b1f32ba3b955c018626127602c365f986ccfc
parent[AF_KEY]: Fix skb leak on pfkey_send_migrate() error (diff)
downloadlinux-dev-68365458a4252fa993b91a00f7a0b18fed399f0d.tar.xz
linux-dev-68365458a4252fa993b91a00f7a0b18fed399f0d.zip
[NET]: rtnl_link: fix use-after-free
When unregistering the rtnl_link_ops, all existing devices using the ops are destroyed. With nested devices this may lead to a use-after-free despite the use of for_each_netdev_safe() in case the upper device is next in the device list and is destroyed by the NETDEV_UNREGISTER notifier. The easy fix is to restart scanning the device list after removing a device. Alternatively we could add new devices to the front of the list to avoid having dependant devices follow the device they depend on. A third option would be to only restart scanning if dev->iflink of the next device matches dev->ifindex of the current one. For now this seems like the safest solution. With this patch, the veth rtnl_link_ops unregistration can use rtnl_link_unregister() directly since it now also handles destruction of multiple devices at once. Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--drivers/net/veth.c14
-rw-r--r--net/core/rtnetlink.c5
2 files changed, 5 insertions, 14 deletions
diff --git a/drivers/net/veth.c b/drivers/net/veth.c
index 43af9e9b2652..3f67a29593bc 100644
--- a/drivers/net/veth.c
+++ b/drivers/net/veth.c
@@ -459,19 +459,7 @@ static __init int veth_init(void)
static __exit void veth_exit(void)
{
- struct veth_priv *priv, *next;
-
- rtnl_lock();
- /*
- * cannot trust __rtnl_link_unregister() to unregister all
- * devices, as each ->dellink call will remove two devices
- * from the list at once.
- */
- list_for_each_entry_safe(priv, next, &veth_list, list)
- veth_dellink(priv->dev);
-
- __rtnl_link_unregister(&veth_link_ops);
- rtnl_unlock();
+ rtnl_link_unregister(&veth_link_ops);
}
module_init(veth_init);
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index e1ba26fb4bf2..fed95a323b28 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -308,9 +308,12 @@ void __rtnl_link_unregister(struct rtnl_link_ops *ops)
struct net *net;
for_each_net(net) {
+restart:
for_each_netdev_safe(net, dev, n) {
- if (dev->rtnl_link_ops == ops)
+ if (dev->rtnl_link_ops == ops) {
ops->dellink(dev);
+ goto restart;
+ }
}
}
list_del(&ops->list);