| From 690bb6fb64f5dc7437317153902573ecad67593d Mon Sep 17 00:00:00 2001 |
| From: Sven Eckelmann <sven@narfation.org> |
| Date: Mon, 28 Feb 2022 00:01:24 +0100 |
| Subject: batman-adv: Request iflink once in batadv-on-batadv check |
| |
| From: Sven Eckelmann <sven@narfation.org> |
| |
| commit 690bb6fb64f5dc7437317153902573ecad67593d upstream. |
| |
| There is no need to call dev_get_iflink multiple times for the same |
| net_device in batadv_is_on_batman_iface. 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: b7eddd0b3950 ("batman-adv: prevent using any virtual device created on batman-adv as hard-interface") |
| Signed-off-by: Sven Eckelmann <sven@narfation.org> |
| Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| net/batman-adv/hard-interface.c | 9 +++++---- |
| 1 file changed, 5 insertions(+), 4 deletions(-) |
| |
| --- a/net/batman-adv/hard-interface.c |
| +++ b/net/batman-adv/hard-interface.c |
| @@ -151,22 +151,23 @@ static bool batadv_is_on_batman_iface(co |
| struct net *net = dev_net(net_dev); |
| struct net_device *parent_dev; |
| struct net *parent_net; |
| + int iflink; |
| bool ret; |
| |
| /* check if this is a batman-adv mesh interface */ |
| if (batadv_softif_is_valid(net_dev)) |
| return true; |
| |
| + iflink = dev_get_iflink(net_dev); |
| + |
| /* no more parents..stop recursion */ |
| - if (dev_get_iflink(net_dev) == 0 || |
| - dev_get_iflink(net_dev) == net_dev->ifindex) |
| + if (iflink == 0 || iflink == net_dev->ifindex) |
| return false; |
| |
| parent_net = batadv_getlink_net(net_dev, net); |
| |
| /* recurse over the parent device */ |
| - parent_dev = __dev_get_by_index((struct net *)parent_net, |
| - dev_get_iflink(net_dev)); |
| + parent_dev = __dev_get_by_index((struct net *)parent_net, iflink); |
| /* if we got a NULL parent_dev there is something broken.. */ |
| if (!parent_dev) { |
| pr_err("Cannot find parent device\n"); |