87 lines
3.2 KiB
Diff
87 lines
3.2 KiB
Diff
From: Sven Eckelmann <sven@narfation.org>
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Date: Wed, 2 Mar 2022 19:49:46 +0100
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Subject: batman-adv: Don't expect inter-netns unique iflink indices
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The ifindex doesn't have to be unique for multiple network namespaces on
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the same machine.
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$ ip netns add test1
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$ ip -net test1 link add dummy1 type dummy
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$ ip netns add test2
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$ ip -net test2 link add dummy2 type dummy
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$ ip -net test1 link show dev dummy1
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6: dummy1: <BROADCAST,NOARP> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000
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link/ether 96:81:55:1e:dd:85 brd ff:ff:ff:ff:ff:ff
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$ ip -net test2 link show dev dummy2
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6: dummy2: <BROADCAST,NOARP> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000
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link/ether 5a:3c:af:35:07:c3 brd ff:ff:ff:ff:ff:ff
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But the batman-adv code to walk through the various layers of virtual
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interfaces uses this assumption because dev_get_iflink handles it
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internally and doesn't return the actual netns of the iflink. And
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dev_get_iflink only documents the situation where ifindex == iflink for
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physical devices.
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But only checking for dev->netdev_ops->ndo_get_iflink is also not an option
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because ipoib_get_iflink implements it even when it sometimes returns an
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iflink != ifindex and sometimes iflink == ifindex. The caller must
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therefore make sure itself to check both netns and iflink + ifindex for
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equality. Only when they are equal, a "physical" interface was detected
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which should stop the traversal. On the other hand, vxcan_get_iflink can
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also return 0 in case there was currently no valid peer. In this case, it
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is still necessary to stop.
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Fixes: 3d48811b27f5 ("batman-adv: prevent using any virtual device created on batman-adv as hard-interface")
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Fixes: 2b45bb6c3aad ("batman-adv: additional checks for virtual interfaces on top of WiFi")
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Reported-by: Sabrina Dubroca <sd@queasysnail.net>
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Signed-off-by: Sven Eckelmann <sven@narfation.org>
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Origin: upstream, https://git.open-mesh.org/batman-adv.git/commit/0aac7a9fbbbeec25f2f54a9e6d53ea91217ba720
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--- a/net/batman-adv/hard-interface.c
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+++ b/net/batman-adv/hard-interface.c
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@@ -157,13 +157,15 @@ static bool batadv_is_on_batman_iface(co
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return true;
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iflink = dev_get_iflink(net_dev);
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-
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- /* no more parents..stop recursion */
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- if (iflink == 0 || iflink == net_dev->ifindex)
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+ if (iflink == 0)
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return false;
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parent_net = batadv_getlink_net(net_dev, net);
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+ /* iflink to itself, most likely physical device */
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+ if (net == parent_net && iflink == net_dev->ifindex)
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+ return false;
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+
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/* recurse over the parent device */
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parent_dev = __dev_get_by_index((struct net *)parent_net, iflink);
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/* if we got a NULL parent_dev there is something broken.. */
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@@ -223,8 +225,7 @@ static struct net_device *batadv_get_rea
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return NULL;
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iflink = dev_get_iflink(netdev);
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-
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- if (netdev->ifindex == iflink) {
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+ if (iflink == 0) {
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dev_hold(netdev);
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return netdev;
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}
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@@ -235,6 +236,14 @@ static struct net_device *batadv_get_rea
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net = dev_net(hard_iface->soft_iface);
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real_net = batadv_getlink_net(netdev, net);
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+
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+ /* iflink to itself, most likely physical device */
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+ if (net == real_net && netdev->ifindex == iflink) {
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+ real_netdev = netdev;
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+ dev_hold(real_netdev);
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+ goto out;
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+ }
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+
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real_netdev = dev_get_by_index(real_net, iflink);
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out:
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