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

[Sabrina Dubroca <sd@queasysnail.net>]

2024-04-14, 13:45:00 +0300, Leon Romanovsky wrote:
> On Thu, Apr 11, 2024 at 10:00:07PM +0200, Sabrina Dubroca wrote:
> > 2024-04-11, 14:55:57 +0300, Leon Romanovsky wrote:
> > > 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.
> > 
> > Nothing is going to break with this change. Old scripts and old
> > userspace software are not providing XFRMA_SA_DIR, so none of the new
> > checks apply.
> 
> Right, but what about new iproute2, which eventually will users get
> after system update and old scripts?

I suspect that new iproute2 will add an option to set the direction
(otherwise it'd have to guess a value, that's not the goal of xfrm
support in iproute), and only pass XFRMA_SA_DIR when the user gave
that extra argument, so nothing will change there either?

-- 
Sabrina