xfrm regression in 5.10.94

Kai Lüke
2022-02-28T12:22:20Z

Hi,

in 5.10.94 these two xfrm changes cause userspace programs like Cilium to
suddenly fail (https://github.com/cilium/cilium/pull/18789):
- xfrm: interface with if_id 0 should return error
8dce43919566f06e865f7e8949f5c10d8c2493f5
- xfrm: state and policy should fail if XFRMA_IF_ID 0
68ac0f3810e76a853b5f7b90601a05c3048b8b54

I see that these changes are a reaction to
- xfrm: fix disable_xfrm sysctl when used on xfrm interfaces
9f8550e4bd9d
but even if the "wrong" usage caused weird behavior I still wonder if it
was the right decision to do the changes as part of a bugfix update for an
LTS kernel.
What do you think about reverting the changes at least for 5.10?

Regards,
Kai