Re: Issue with iwd + Linux 5.8.3 + WPA Enterprise

From: Ard Biesheuvel
Date: Wed Aug 26 2020 - 08:00:54 EST


On Wed, 26 Aug 2020 at 13:50, Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> wrote:
>
> On Wed, Aug 26, 2020 at 12:40:14PM +0200, Ard Biesheuvel wrote:
> >
> > It would be helpful if someone could explain for the non-mac80211
> > enlightened readers how iwd's EAP-PEAPv0 + MSCHAPv2 support relies on
> > the algif_aead socket interface, and which AEAD algorithms it uses. I
> > assume this is part of libell?
>
> I see the problem. libell/ell/checksum.c doesn't clear the MSG_MORE
> flag before doing the recv(2).
>

But that code uses a hash not an aead, afaict.

> I was hoping nobody out there was doing this but obviously I've
> been proven wrong.
>
> So what I'm going to do is to specifically allow this case of
> a string of sendmsg(2)'s with MSG_MORE folloed by a recvmsg(2)
> in the same thread. I'll add a WARN_ON_ONCE so user-space can
> eventually be fixed.
>
> Cheers,
> --
> Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
> Home Page: http://gondor.apana.org.au/~herbert/
> PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt