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Subject: Re: [PATCH net-next] [RESEND] wireguard: disable in FIPS mode
From:   Simo Sorce <simo@redhat.com>
To:     Hangbin Liu <liuhangbin@gmail.com>,
        Stephan Mueller <smueller@chronox.de>
Cc:     Eric Biggers <ebiggers@kernel.org>, netdev@vger.kernel.org,
        "Jason A . Donenfeld" <Jason@zx2c4.com>,
        Toke =?ISO-8859-1?Q?H=F8iland-J=F8rgensen?= <toke@redhat.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        Ondrej Mosnacek <omosnace@redhat.com>,
        linux-crypto@vger.kernel.org
Date:   Fri, 09 Apr 2021 12:26:23 -0400
In-Reply-To: <20210409080804.GO2900@Leo-laptop-t470s>
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On Fri, 2021-04-09 at 16:08 +0800, Hangbin Liu wrote:
> On Fri, Apr 09, 2021 at 09:08:20AM +0200, Stephan Mueller wrote:
> > > > > > > And how do you handle all the other places in the kernel that use
> > > > > > > ChaCha20 and
> > > > > > > SipHash?  For example, drivers/char/random.c?
> > > > > > 
> > > > > > Good question, I will check it and reply to you later.
> > > > > 
> > > > > I just read the code. The drivers/char/random.c do has some fips
> > > > > specific
> > > > > parts(seems not related to crypto). After commit e192be9d9a30 ("random:
> > > > > replace
> > > > > non-blocking pool with a Chacha20-based CRNG") we moved part of chacha
> > > > > code to
> > > > > lib/chacha20.c and make that code out of control.
> > > > > 
> > > > So you are saying that you removed drivers/char/random.c and
> > > > lib/chacha20.c from
> > > > your FIPS module boundary?  Why not do the same for WireGuard?
> > > 
> > > No, I mean this looks like a bug (using not allowed crypto in FIPS mode) and
> > > we should fix it.
> > 
> > The entirety of random.c is not compliant to FIPS rules. ChaCha20 is the least
> > of the problems. SP800-90B is the challenge. This is one of the motivation of
> > the design and architecture of the LRNG allowing different types of crypto and
> > have a different approach to post-process the data.
> > 
> > https://github.com/smuellerDD/lrng
> 
> Thanks Stephan for this info. After offline discussion with Herbert, here is
> what he said:
> 
> """
> This is not a problem in RHEL8 because the Crypto API RNG replaces /dev/random
> in FIPS mode.
> """
> 
> I'm not familiar with this code, not sure how upstream handle this.

It is an open problem upstream.

Simo.

-- 
Simo Sorce
RHEL Crypto Team
Red Hat, Inc