From 130ec90cb3a20a6635fad5307a47f4c5155b74cc Mon Sep 17 00:00:00 2001 From: Sven Eckelmann Date: Mon, 28 Feb 2022 00:01:24 +0100 Subject: batman-adv: Request iflink once in batadv_get_real_netdevice commit 6116ba09423f7d140f0460be6a1644dceaad00da upstream. 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: 5ed4a460a1d3 ("batman-adv: additional checks for virtual interfaces on top of WiFi") Signed-off-by: Sven Eckelmann Signed-off-by: Simon Wunderlich Signed-off-by: Greg Kroah-Hartman --- net/batman-adv/hard-interface.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/net/batman-adv/hard-interface.c b/net/batman-adv/hard-interface.c index 427be0f6586f..93d36c5189ab 100644 --- a/net/batman-adv/hard-interface.c +++ b/net/batman-adv/hard-interface.c @@ -228,14 +228,16 @@ 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; } @@ -245,9 +247,8 @@ 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: if (hard_iface) -- cgit v1.2.3