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| author | Eric W. Biederman <ebiederm@aristanetworks.com> | 2011-03-21 18:22:22 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2011-03-21 18:22:22 -0700 |
| commit | d5cd92448fded12c91f7574e49747c5f7d975a8d (patch) | |
| tree | c65c8f66d7818b4250d56ef489cb2b3125276403 /drivers/net/macvlan.c | |
| parent | ac0a121d7906b049dfee3649f886c969fbb3c1b7 (diff) | |
| download | lwn-d5cd92448fded12c91f7574e49747c5f7d975a8d.tar.gz lwn-d5cd92448fded12c91f7574e49747c5f7d975a8d.zip | |
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 <ebiederm@aristanetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/macvlan.c')
| -rw-r--r-- | drivers/net/macvlan.c | 18 |
1 files changed, 12 insertions, 6 deletions
diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c index 5b37d3c191e4..78e34e9e4f00 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); |