3.6.11.5 stable review patch. If anyone has any objections, please let me know.
------------------ From: Jiri Pirko <[email protected]> [ Upstream commit 233c7df0821c4190e2d3f4be0f2ca0ab40a5ed8c ] Currently, if macvlan in passthru mode is created and data are rxed and you remove this device, following panic happens: NULL pointer dereference at 0000000000000198 IP: [<ffffffffa0196058>] macvlan_handle_frame+0x153/0x1f7 [macvlan] I'm using following script to trigger this: <script> while [ 1 ] do ip link add link e1 name macvtap0 type macvtap mode passthru ip link set e1 up ip link set macvtap0 up IFINDEX=`ip link |grep macvtap0 | cut -f 1 -d ':'` cat /dev/tap$IFINDEX >/dev/null & ip link del dev macvtap0 done </script> I run this script while "ping -f" is running on another machine to send packets to e1 rx. Reason of the panic is that list_first_entry() is blindly called in macvlan_handle_frame() even if the list was empty. vlan is set to incorrect pointer which leads to the crash. I'm fixing this by protecting port->vlans list by rcu and by preventing from getting incorrect pointer in case the list is empty. Introduced by: commit eb06acdc85585f2 "macvlan: Introduce 'passthru' mode to takeover the underlying device" Signed-off-by: Jiri Pirko <[email protected]> Acked-by: Eric Dumazet <[email protected]> Signed-off-by: David S. Miller <[email protected]> Signed-off-by: Steven Rostedt <[email protected]> --- drivers/net/macvlan.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c index 666fc20..0bec603 100644 --- a/drivers/net/macvlan.c +++ b/drivers/net/macvlan.c @@ -204,7 +204,8 @@ static rx_handler_result_t macvlan_handle_frame(struct sk_buff **pskb) } if (port->passthru) - vlan = list_first_entry(&port->vlans, struct macvlan_dev, list); + vlan = list_first_or_null_rcu(&port->vlans, + struct macvlan_dev, list); else vlan = macvlan_hash_lookup(port, eth->h_dest); if (vlan == NULL) @@ -771,7 +772,7 @@ int macvlan_common_newlink(struct net *src_net, struct net_device *dev, if (err < 0) goto destroy_port; - list_add_tail(&vlan->list, &port->vlans); + list_add_tail_rcu(&vlan->list, &port->vlans); netif_stacked_transfer_operstate(lowerdev, dev); return 0; @@ -797,7 +798,7 @@ void macvlan_dellink(struct net_device *dev, struct list_head *head) { struct macvlan_dev *vlan = netdev_priv(dev); - list_del(&vlan->list); + list_del_rcu(&vlan->list); unregister_netdevice_queue(dev, head); } EXPORT_SYMBOL_GPL(macvlan_dellink); -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
