batman-adv: Request iflink once in batadv_get_real_netdevice

There is no need to call dev_get_iflink multiple times for the same
net_device in batadv_get_real_netdevice. And since some of the
ndo_get_iflink callbacks are dynamic (for example via RCUs like in
vxcan_get_iflink), it could easily happen that the returned values are not
stable. The pre-checks before __dev_get_by_index are then of course bogus.

Fixes: 5ed4a460a1 ("batman-adv: additional checks for virtual interfaces on top of WiFi")
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
This commit is contained in:
Sven Eckelmann 2022-02-28 00:01:24 +01:00 committed by Simon Wunderlich
parent 690bb6fb64
commit 6116ba0942

View File

@ -215,14 +215,16 @@ static struct net_device *batadv_get_real_netdevice(struct net_device *netdev)
struct net_device *real_netdev = NULL;
struct net *real_net;
struct net *net;
int ifindex;
int iflink;
ASSERT_RTNL();
if (!netdev)
return NULL;
if (netdev->ifindex == dev_get_iflink(netdev)) {
iflink = dev_get_iflink(netdev);
if (netdev->ifindex == iflink) {
dev_hold(netdev);
return netdev;
}
@ -232,9 +234,8 @@ static struct net_device *batadv_get_real_netdevice(struct net_device *netdev)
goto out;
net = dev_net(hard_iface->soft_iface);
ifindex = dev_get_iflink(netdev);
real_net = batadv_getlink_net(netdev, net);
real_netdev = dev_get_by_index(real_net, ifindex);
real_netdev = dev_get_by_index(real_net, iflink);
out:
batadv_hardif_put(hard_iface);