Re: [PATCH] crypto: mark cts(cbc(aes)) as FIPS allowed

From: Stephan Mueller
Date: Mon Nov 05 2018 - 05:30:19 EST


Am Montag, 5. November 2018, 11:20:28 CET schrieb Ard Biesheuvel:

Hi Ard, Gilad,

> On 5 November 2018 at 10:18, Gilad Ben-Yossef <gilad@xxxxxxxxxxxxx> wrote:
> > Hi Stephan,
> >
> > On Mon, Nov 5, 2018 at 10:50 AM Stephan Mueller <smueller@xxxxxxxxxx>
wrote:
> >> Am Sonntag, 4. November 2018, 11:05:24 CET schrieb Gilad Ben-Yossef:
> >>
> >> Hi Gilad,
> >>
> >> > As per Sp800-38A addendum from Oct 2010[1], cts(cbc(aes)) is
> >> > allowed as a FIPS mode algorithm. Mark it as such.
> >> >
> >> > [1] https://csrc.nist.gov/publications/detail/sp/800-38a/addendum/final
> >>
> >> There are several types of CTS approaches. Only three of those are listed
> >> in the SP800-38A addendum. The source code only refers to some RFCs.
> >>
> >> Did you check whether the CTS implementation matches one or more of the
> >> types listed in the addendum? If yes, may I suggest to add a small
> >> statement in the code noting this fact?
> >
> > Yes, AFAIK the software implements CBC-CS3 as described in the document.
> > You have a very good point about this not document anywhere. I will
> > send a patch.
>
> I agree that it makes sense to document this.

Thanks for adding this. With this statement, the initial patch of adding the
fips_allowed flag is:

Reviewed-by: Stephan Mueller <smueller@xxxxxxxxxx>

Ciao
Stephan