Le 09/03/2022 à 23:20, Ilya Maximets a écrit :
> Few years ago OVS user space made a strange choice in the commit [1]
> to define types only valid for the user space inside the copy of a
> kernel uAPI header. '#ifndef __KERNEL__' and another attribute was
> added later.
>
> This leads to the inevitable clash between user space and kernel types
> when the kernel uAPI is extended. The issue was unveiled with the
> addition of a new type for IPv6 extension header in kernel uAPI.
>
> When kernel provides the OVS_KEY_ATTR_IPV6_EXTHDRS attribute to the
> older user space application, application tries to parse it as
> OVS_KEY_ATTR_PACKET_TYPE and discards the whole netlink message as
> malformed. Since OVS_KEY_ATTR_IPV6_EXTHDRS is supplied along with
> every IPv6 packet that goes to the user space, IPv6 support is fully
> broken.
>
> Fixing that by bringing these user space attributes to the kernel
> uAPI to avoid the clash. Strictly speaking this is not the problem
> of the kernel uAPI, but changing it is the only way to avoid breakage
> of the older user space applications at this point.
>
> These 2 types are explicitly rejected now since they should not be
> passed to the kernel. Additionally, OVS_KEY_ATTR_TUNNEL_INFO moved
> out from the '#ifdef __KERNEL__' as there is no good reason to hide
> it from the userspace. And it's also explicitly rejected now, because
> it's for in-kernel use only.
>
> Comments with warnings were added to avoid the problem coming back.
>
> (1 << type) converted to (1ULL << type) to avoid integer overflow on
> OVS_KEY_ATTR_IPV6_EXTHDRS, since it equals 32 now.
>
> [1] beb75a40fdc2 ("userspace: Switching of L3 packets in L2 pipeline")
>
> Fixes: 28a3f0601727 ("net: openvswitch: IPv6: Add IPv6 extension header
> support")
> Link:
> https://lore.kernel.org/netdev/3adf00c7-fe65-3ef4-b6d7-6d8a0cad8...@nvidia.com
> Link:
> https://github.com/openvswitch/ovs/commit/beb75a40fdc295bfd6521b0068b4cd12f6de507c
> Reported-by: Roi Dayan <r...@nvidia.com>
> Signed-off-by: Ilya Maximets <i.maxim...@ovn.org>
Thanks for finally doing this. I also suggest it months ago:
https://lore.kernel.org/lkml/a4894aef-b82a-8224-611d-07be229f5...@6wind.com/
Acked-by: Nicolas Dichtel <nicolas.dich...@6wind.com>
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