netdev - Re: [PATCH v2 ipsec 2/2] xfrm: Ensure policy checked for nested ESP tunnels

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Date:   Thu, 22 Sep 2022 18:33:55 -0700
From:   Benedict Wong <benedictwong@...gle.com>
To:     Steffen Klassert <steffen.klassert@...unet.com>
Cc:     netdev@...r.kernel.org, nharold@...gle.com, lorenzo@...gle.com
Subject: Re: [PATCH v2 ipsec 2/2] xfrm: Ensure policy checked for nested ESP tunnels

Ahh, I've never had an IPv4 server without a NAT to test against, I'd presume
this is identical there. The only comparison that I've been able to do  was IPv4
UDP-encap vs IPv6 ESP.

We could instead add the policy check to the ESP input path if that is
the correct place.


On Wed, Sep 21, 2022 at 11:27 PM Steffen Klassert
<steffen.klassert@...unet.com> wrote:
>
> On Fri, Sep 16, 2022 at 10:44:42PM -0700, Benedict Wong wrote:
> > Thanks for the response; apologies for taking a while to re-patch this
> > and verify.
> >
> > I think this /almost/ does what we need to. I'm still seeing v6 ESP in v6
> > ESP tunnels failing; I think it's due to the fact that the IPv6 ESP
> > codepath does not trigger policy checks in the receive codepath until it
> > hits the socket, or changes namespace.
> > Perhaps if we verify policy unconditionally in xfrmi_rcv_cb? combined
> > with your change above, this should ensure IPv6 ESP also checks policies,
> > and inside that clear the secpath?
>
> Hm, do you know why this is different to IPv4? IPv4 and IPv6 should
> do the same regarding to policy checks.
>