Re: [devel-ipsec] [PATCH ipsec-next v8] xfrm: Add Direction to the SA in or out

[Leon Romanovsky <leon@kernel.org>]

On Thu, Apr 11, 2024 at 01:07:52PM +0200, Antony Antony via Devel wrote:
> On Thu, Apr 11, 2024 at 01:37:40PM +0300, Leon Romanovsky via Devel wrote:
> > On Tue, Apr 09, 2024 at 07:37:20PM +0200, Antony Antony via Devel wrote:
> > > This patch introduces the 'dir' attribute, 'in' or 'out', to the
> > > xfrm_state, SA, enhancing usability by delineating the scope of values
> > > based on direction. An input SA will now exclusively encompass values
> > > pertinent to input, effectively segregating them from output-related
> > > values. This change aims to streamline the configuration process and
> > > improve the overall clarity of SA attributes.
> > > 
> > > This feature sets the groundwork for future patches, including
> > > the upcoming IP-TFS patch.
> > > 
> > > v7->v8:
> > >  - add extra validation check on replay window and seq
> > >  - XFRM_MSG_UPDSA old and new SA should match "dir"
> > 
> > Why? Update is add and delete operation, and one can update any field
> > he/she wants, including direction.
> 
> Update operations are not strictly necessary without IKEv2. However, during
> IKEv2 negotiation, updating "in" SA becomes essential.

The thing is if you want to limit update routine to fit IKEv2 only, or
continue to allow users to do whatever they want with netlink and their
own applications without *swan.

I don't have knowledge about such users, just remember seeking tons of
guides how to setup IPsec tunnel with iproute2 and scripts, one of them
can be potentially broken by this change.

Thanks