From d5cd92448fded12c91f7574e49747c5f7d975a8d Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Mon, 21 Mar 2011 18:22:22 -0700 Subject: macvlan: Fix use after free of struct macvlan_port. When the macvlan driver was extended to call unregisgter_netdevice_queue in 23289a37e2b127dfc4de1313fba15bb4c9f0cd5b, a use after free of struct macvlan_port was introduced. The code in dellink relied on unregister_netdevice actually unregistering the net device so it would be safe to free macvlan_port. Since unregister_netdevice_queue can just queue up the unregister instead of performing the unregiser immediately we free the macvlan_port too soon and then the code in macvlan_stop removes the macaddress for the set of macaddress to listen for and uses memory that has already been freed. To fix this add a reference count to track when it is safe to free the macvlan_port and move the call of macvlan_port_destroy into macvlan_uninit which is guaranteed to be called after the final macvlan_port_close. Signed-off-by: Eric W. Biederman Signed-off-by: David S. Miller --- drivers/net/macvlan.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) (limited to 'drivers/net/macvlan.c') diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c index 5b37d3c191e..78e34e9e4f0 100644 --- a/drivers/net/macvlan.c +++ b/drivers/net/macvlan.c @@ -39,8 +39,11 @@ struct macvlan_port { struct list_head vlans; struct rcu_head rcu; bool passthru; + int count; }; +static void macvlan_port_destroy(struct net_device *dev); + #define macvlan_port_get_rcu(dev) \ ((struct macvlan_port *) rcu_dereference(dev->rx_handler_data)) #define macvlan_port_get(dev) ((struct macvlan_port *) dev->rx_handler_data) @@ -457,8 +460,13 @@ static int macvlan_init(struct net_device *dev) static void macvlan_uninit(struct net_device *dev) { struct macvlan_dev *vlan = netdev_priv(dev); + struct macvlan_port *port = vlan->port; free_percpu(vlan->pcpu_stats); + + port->count -= 1; + if (!port->count) + macvlan_port_destroy(port->dev); } static struct rtnl_link_stats64 *macvlan_dev_get_stats64(struct net_device *dev, @@ -691,12 +699,13 @@ int macvlan_common_newlink(struct net *src_net, struct net_device *dev, vlan->mode = nla_get_u32(data[IFLA_MACVLAN_MODE]); if (vlan->mode == MACVLAN_MODE_PASSTHRU) { - if (!list_empty(&port->vlans)) + if (port->count) return -EINVAL; port->passthru = true; memcpy(dev->dev_addr, lowerdev->dev_addr, ETH_ALEN); } + port->count += 1; err = register_netdevice(dev); if (err < 0) goto destroy_port; @@ -707,7 +716,8 @@ int macvlan_common_newlink(struct net *src_net, struct net_device *dev, return 0; destroy_port: - if (list_empty(&port->vlans)) + port->count -= 1; + if (!port->count) macvlan_port_destroy(lowerdev); return err; @@ -725,13 +735,9 @@ static int macvlan_newlink(struct net *src_net, struct net_device *dev, void macvlan_dellink(struct net_device *dev, struct list_head *head) { struct macvlan_dev *vlan = netdev_priv(dev); - struct macvlan_port *port = vlan->port; list_del(&vlan->list); unregister_netdevice_queue(dev, head); - - if (list_empty(&port->vlans)) - macvlan_port_destroy(port->dev); } EXPORT_SYMBOL_GPL(macvlan_dellink); -- cgit v1.2.3