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authorSven Eckelmann <sven@narfation.org>2022-02-27 23:23:49 +0100
committerSimon Wunderlich <sw@simonwunderlich.de>2022-03-02 09:24:55 +0100
commit6c1f41afc1dbe59d9d3c8bb0d80b749c119aa334 (patch)
treec61eea2166c351fa2695dcde751b94d0486b464f /net
parent6116ba09423f7d140f0460be6a1644dceaad00da (diff)
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batman-adv: Don't expect inter-netns unique iflink indices
The ifindex doesn't have to be unique for multiple network namespaces on the same machine. $ ip netns add test1 $ ip -net test1 link add dummy1 type dummy $ ip netns add test2 $ ip -net test2 link add dummy2 type dummy $ ip -net test1 link show dev dummy1 6: dummy1: <BROADCAST,NOARP> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000 link/ether 96:81:55:1e:dd:85 brd ff:ff:ff:ff:ff:ff $ ip -net test2 link show dev dummy2 6: dummy2: <BROADCAST,NOARP> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000 link/ether 5a:3c:af:35:07:c3 brd ff:ff:ff:ff:ff:ff But the batman-adv code to walk through the various layers of virtual interfaces uses this assumption because dev_get_iflink handles it internally and doesn't return the actual netns of the iflink. And dev_get_iflink only documents the situation where ifindex == iflink for physical devices. But only checking for dev->netdev_ops->ndo_get_iflink is also not an option because ipoib_get_iflink implements it even when it sometimes returns an iflink != ifindex and sometimes iflink == ifindex. The caller must therefore make sure itself to check both netns and iflink + ifindex for equality. Only when they are equal, a "physical" interface was detected which should stop the traversal. On the other hand, vxcan_get_iflink can also return 0 in case there was currently no valid peer. In this case, it is still necessary to stop. Fixes: b7eddd0b3950 ("batman-adv: prevent using any virtual device created on batman-adv as hard-interface") Fixes: 5ed4a460a1d3 ("batman-adv: additional checks for virtual interfaces on top of WiFi") Reported-by: Sabrina Dubroca <sd@queasysnail.net> Signed-off-by: Sven Eckelmann <sven@narfation.org> Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
Diffstat (limited to 'net')
-rw-r--r--net/batman-adv/hard-interface.c19
1 files changed, 14 insertions, 5 deletions
diff --git a/net/batman-adv/hard-interface.c b/net/batman-adv/hard-interface.c
index e2760cfce190..35fadb924849 100644
--- a/net/batman-adv/hard-interface.c
+++ b/net/batman-adv/hard-interface.c
@@ -157,13 +157,15 @@ static bool batadv_is_on_batman_iface(const struct net_device *net_dev)
return true;
iflink = dev_get_iflink(net_dev);
-
- /* no more parents..stop recursion */
- if (iflink == 0 || iflink == net_dev->ifindex)
+ if (iflink == 0)
return false;
parent_net = batadv_getlink_net(net_dev, net);
+ /* iflink to itself, most likely physical device */
+ if (net == parent_net && iflink == net_dev->ifindex)
+ return false;
+
/* recurse over the parent device */
parent_dev = __dev_get_by_index((struct net *)parent_net, iflink);
/* if we got a NULL parent_dev there is something broken.. */
@@ -223,8 +225,7 @@ static struct net_device *batadv_get_real_netdevice(struct net_device *netdev)
return NULL;
iflink = dev_get_iflink(netdev);
-
- if (netdev->ifindex == iflink) {
+ if (iflink == 0) {
dev_hold(netdev);
return netdev;
}
@@ -235,6 +236,14 @@ static struct net_device *batadv_get_real_netdevice(struct net_device *netdev)
net = dev_net(hard_iface->soft_iface);
real_net = batadv_getlink_net(netdev, net);
+
+ /* iflink to itself, most likely physical device */
+ if (net == real_net && netdev->ifindex == iflink) {
+ real_netdev = netdev;
+ dev_hold(real_netdev);
+ goto out;
+ }
+
real_netdev = dev_get_by_index(real_net, iflink);
out: