Re: Issue with iwd + Linux 5.8.3 + WPA Enterprise

From: Ard Biesheuvel
Date: Wed Aug 26 2020 - 11:42:46 EST


On Wed, 26 Aug 2020 at 17:33, Denis Kenzior <denkenz@xxxxxxxxx> wrote:
>
> Hi Herbert,
>
> On 8/26/20 9:19 AM, Herbert Xu wrote:
> > On Wed, Aug 26, 2020 at 08:57:17AM -0500, Denis Kenzior wrote:
> >>
> >> I'm just waking up now, so I might seem dense, but for my education, can you
> >> tell me why we need to set MSG_MORE when we issue just a single sendmsg
> >> followed immediately by recv/recvmsg? ell/iwd operates on small buffers, so
> >> we don't really feed the kernel data in multiple send operations. You can
> >> see this in the ell git tree link referenced in Andrew's reply.
> >
> > You obviously don't need MSG_MORE if you're doing a single sendmsg.
> >
> > The problematic code is in l_cipher_set_iv. It does a sendmsg(2)
> > that expects to be followed by more sendmsg(2) calls before a
> > recvmsg(2). That's the one that needs a MSG_MORE.
> >
>
> Gotcha. I fixed the set_iv part now in ell:
> https://git.kernel.org/pub/scm/libs/ell/ell.git/commit/?id=87c76bbc85fe286925cbdb53d733fc9f9fd2ed12
>

Interestingly, that change alone (without the kernel side fix that
Herbert just provided) is not sufficient to make the self tests work
again.

I still get a failure in aes_siv_encrypt(), which does not occur with
the kernel side fix applied.