Re: [PATCH 2/2] crypto: s5p - use correct block size of 1 for ctr(aes)

From: Krzysztof Kozlowski <krzk@kernel.org>
To: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: "open list:HARDWARE RANDOM NUMBER GENERATOR CORE" 
	<linux-crypto@vger.kernel.org>,
	Herbert Xu <herbert@gondor.apana.org.au>,
	Vladimir Zapolskiy <vz@mleia.com>,
	Kamil Konieczny <k.konieczny@partner.samsung.com>,
	"linux-samsung-soc@vger.kernel.org" 
	<linux-samsung-soc@vger.kernel.org>
Subject: Re: [PATCH 2/2] crypto: s5p - use correct block size of 1 for ctr(aes)
Date: Tue, 20 Aug 2019 13:23:58 +0200	[thread overview]
Message-ID: <CAJKOXPfReqxQZfN8TdpPQZLbNEgkWm7_KinQz=qvQxQ4_vOowA@mail.gmail.com> (raw)
In-Reply-To: <CAKv+Gu9Z=qkEVpkQYsCy5Q_EvMuQ1KzPVataWs+x4vhS_wB27Q@mail.gmail.com>

On Tue, 20 Aug 2019 at 12:57, Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote:
>
> On Tue, 20 Aug 2019 at 13:24, Krzysztof Kozlowski <krzk@kernel.org> wrote:
> >
> > On Mon, 19 Aug 2019 at 16:24, Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote:
> > >
> > > Align the s5p ctr(aes) implementation with other implementations
> > > of the same mode, by setting the block size to 1.
> > >
> > > Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> > > ---
> > >  drivers/crypto/s5p-sss.c | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/crypto/s5p-sss.c b/drivers/crypto/s5p-sss.c
> > > index ef90c58edb1f..010f1bb20dad 100644
> > > --- a/drivers/crypto/s5p-sss.c
> > > +++ b/drivers/crypto/s5p-sss.c
> > > @@ -2173,7 +2173,7 @@ static struct crypto_alg algs[] = {
> > >                 .cra_flags              = CRYPTO_ALG_TYPE_ABLKCIPHER |
> > >                                           CRYPTO_ALG_ASYNC |
> > >                                           CRYPTO_ALG_KERN_DRIVER_ONLY,
> > > -               .cra_blocksize          = AES_BLOCK_SIZE,
> > > +               .cra_blocksize          = 1,
> >
> > This makes sense but I wonder how does it work later with
> > s5p_aes_crypt() and its check for request length alignment
> > (AES_BLOCK_SIZE). With block size of 1 byte, I understand that
> > req->nbytes can be for example 4 bytes which is not AES block
> > aligned... If my reasoning is correct, then the CTR mode in s5p-sss is
> > not fully working.
> >
>
>
> I re-ran the kernelci.org tests with this change, and I saw no more failures.
>
> https://kernelci.org/boot/all/job/ardb/branch/for-kernelci/kernel/v5.3-rc1-197-gc8809c50be4f/

Indeed, self tests are passing. Anyway the change is correct so:
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>

Best regards,
Krzysztof