Subject: Re: [PATCH xfrm-next v7 4/8] xfrm: add TX datapath support for IPsec packet offload mode

From: Leon Romanovsky <[email-masked]>
Date: Mon, 21 Nov 2022 13:10:15 +0200

On Fri, Nov 18, 2022 at 11:23:10AM +0100, Steffen Klassert wrote:
> On Thu, Nov 17, 2022 at 02:32:10PM +0200, Leon Romanovsky wrote:
> > On Thu, Nov 17, 2022 at 12:59:39PM +0100, Steffen Klassert wrote:
> > > On Wed, Nov 09, 2022 at 02:54:32PM +0200, Leon Romanovsky wrote:
> > > > From: Leon Romanovsky <[email-masked]>
> > > 
> > > > @@ -2708,6 +2710,23 @@ static struct dst_entry *xfrm_bundle_create(struct xfrm_policy *policy,
> > > >  	if (!dev)
> > > >  		goto free_dst;
> > > >  
> > > > +	dst1 = &xdst0->u.dst;
> > > > +	/* Packet offload: both policy and SA should be offloaded */
> > > > +	if ((policy->xdo.type == XFRM_DEV_OFFLOAD_PACKET &&
> > > > +	     dst1->xfrm->xso.type != XFRM_DEV_OFFLOAD_PACKET) ||
> > > > +	    (policy->xdo.type != XFRM_DEV_OFFLOAD_PACKET &&
> > > > +	     dst1->xfrm->xso.type == XFRM_DEV_OFFLOAD_PACKET)) {
> > > > +		err = -EINVAL;
> > > > +		goto free_dst;
> > > > +	}
> > > > +
> > > > +	/* Packet offload: both policy and SA should have same device */
> > > > +	if (policy->xdo.type == XFRM_DEV_OFFLOAD_PACKET &&
> > > > +	    policy->xdo.dev != dst1->xfrm->xso.dev) {
> > > > +		err = -EINVAL;
> > > > +		goto free_dst;
> > > > +	}
> > > > +
> > > 
> > > This is the wrong place for these checks. Things went already wrong
> > > in the lookup if policy and state do not match here.
> > 
> > Where do you think we should put such checks?
> 
> You need to create a new lookup key for this and match the policies
> template against the TS of the state. This happens in xfrm_state_find.
> Unfortunately this affects also the SW datapath even without HW
> policies/states. So please try to make it a NOP if there are no HW
> policies/states.

Do you think that this will be enough?

+static bool xfrm_state_and_policy_mixed(struct xfrm_state *x,
+                                       struct xfrm_policy *p)
+{
+       /* Packet offload: both policy and SA should be offloaded */
+       if (p->xdo.type == XFRM_DEV_OFFLOAD_PACKET &&
+           x->xso.type != XFRM_DEV_OFFLOAD_PACKET)
+               return true;
+
+       if (p->xdo.type != XFRM_DEV_OFFLOAD_PACKET &&
+           x->xso.type == XFRM_DEV_OFFLOAD_PACKET)
+               return true;
+
+       if (p->xdo.type != XFRM_DEV_OFFLOAD_PACKET)
+               return false;
+
+       /* Packet offload: both policy and SA should have same device */
+       if (p->xdo.dev != x->xso.dev)
+               return true;
+
+       return false;
+}
+
 struct xfrm_state *
 xfrm_state_find(const xfrm_address_t *daddr, const xfrm_address_t *saddr,
                const struct flowi *fl, struct xfrm_tmpl *tmpl,
@@ -1228,6 +1250,10 @@ xfrm_state_find(const xfrm_address_t *daddr, const xfrm_address_t *saddr,
                        *err = -EAGAIN;
                        x = NULL;
                }
+               if (x && xfrm_state_and_policy_mixed(x, pol)) {
+                       *err = -EINVAL;
+                       x = NULL;
+               }
        } else {
                *err = acquire_in_progress ? -EAGAIN : error;
        }
(END)