From: Sabrina Dubroca <s...@queasysnail.net>
Date: Tue, 14 May 2019 15:12:19 +0200
> Currently, nla_put_iflink() doesn't put the IFLA_LINK attribute when
> iflink == ifindex.
>
> In some cases, a device can be created in a different netns with the
> same ifindex as its parent. That device will not dump its IFLA_LINK
> attribute, which can confuse some userspace software that expects it.
> For example, if the last ifindex created in init_net and foo are both
> 8, these commands will trigger the issue:
>
> ip link add parent type dummy # ifindex 9
> ip link add link parent netns foo type macvlan # ifindex 9 in ns foo
>
> So, in case a device puts the IFLA_LINK_NETNSID attribute in a dump,
> always put the IFLA_LINK attribute as well.
>
> Thanks to Dan Winship for analyzing the original OpenShift bug down to
> the missing netlink attribute.
>
> v2: change Fixes tag, it's been here forever, as Nicolas Dichtel said
> add Nicolas' ack
> v3: change Fixes tag
> fix subject typo, spotted by Edward Cree
>
> Analyzed-by: Dan Winship <d...@redhat.com>
> Fixes: d8a5ec672768 ("[NET]: netlink support for moving devices between
> network namespaces.")
> Signed-off-by: Sabrina Dubroca <s...@queasysnail.net>
> Acked-by: Nicolas Dichtel <nicolas.dich...@6wind.com>
Applied and queued up for -stable, thank you.
