From 40b9d1ab63f5c4f3cb69450044d07b45e5af72e1 Mon Sep 17 00:00:00 2001 From: Mahesh Bandewar Date: Tue, 15 Nov 2022 17:19:14 -0800 Subject: [PATCH] ipvlan: hold lower dev to avoid possible use-after-free Recently syzkaller discovered the issue of disappearing lower device (NETDEV_UNREGISTER) while the virtual device (like macvlan) is still having it as a lower device. So it's just a matter of time similar discovery will be made for IPvlan device setup. So fixing it preemptively. Also while at it, add a refcount tracker. Fixes: 2ad7bf363841 ("ipvlan: Initial check-in of the IPVLAN driver.") Signed-off-by: Mahesh Bandewar Signed-off-by: David S. Miller --- drivers/net/ipvlan/ipvlan.h | 1 + drivers/net/ipvlan/ipvlan_main.c | 2 ++ 2 files changed, 3 insertions(+) diff --git a/drivers/net/ipvlan/ipvlan.h b/drivers/net/ipvlan/ipvlan.h index de94921..025e0c1 100644 --- a/drivers/net/ipvlan/ipvlan.h +++ b/drivers/net/ipvlan/ipvlan.h @@ -98,6 +98,7 @@ struct ipvl_port { struct sk_buff_head backlog; int count; struct ida ida; + netdevice_tracker dev_tracker; }; struct ipvl_skb_cb { diff --git a/drivers/net/ipvlan/ipvlan_main.c b/drivers/net/ipvlan/ipvlan_main.c index 54c94a6..796a38f 100644 --- a/drivers/net/ipvlan/ipvlan_main.c +++ b/drivers/net/ipvlan/ipvlan_main.c @@ -83,6 +83,7 @@ static int ipvlan_port_create(struct net_device *dev) if (err) goto err; + netdev_hold(dev, &port->dev_tracker, GFP_KERNEL); return 0; err: @@ -95,6 +96,7 @@ static void ipvlan_port_destroy(struct net_device *dev) struct ipvl_port *port = ipvlan_port_get_rtnl(dev); struct sk_buff *skb; + netdev_put(dev, &port->dev_tracker); if (port->mode == IPVLAN_MODE_L3S) ipvlan_l3s_unregister(port); netdev_rx_handler_unregister(dev); -- 2.7.4