diff options
author | Sven Eckelmann <sven@narfation.org> | 2022-02-28 01:23:49 +0300 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-03-08 21:07:47 +0300 |
commit | ed05368024a9c6a0732db077e04c5257be411686 (patch) | |
tree | 8f047c81e0f2b8b9cad96aedd899699a0e6b89ae /net | |
parent | 863953227106e4fee6257bccf1e1c863d1616c41 (diff) | |
download | linux-ed05368024a9c6a0732db077e04c5257be411686.tar.xz |
batman-adv: Don't expect inter-netns unique iflink indices
commit 6c1f41afc1dbe59d9d3c8bb0d80b749c119aa334 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net')
-rw-r--r-- | net/batman-adv/hard-interface.c | 19 |
1 files changed, 14 insertions, 5 deletions
diff --git a/net/batman-adv/hard-interface.c b/net/batman-adv/hard-interface.c index d896208775db..5f44c94ad707 100644 --- a/net/batman-adv/hard-interface.c +++ b/net/batman-adv/hard-interface.c @@ -159,13 +159,15 @@ 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.. */ @@ -225,8 +227,7 @@ 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; } @@ -237,6 +238,14 @@ 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: |