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Date:   Tue, 10 Sep 2019 11:21:34 +1000
From:   Herbert Xu <herbert@gondor.apana.org.au>
To:     Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc:     Gilad Ben-Yossef <gilad@benyossef.com>,
        Uri Shir <uri.shir@arm.com>,
        "David S. Miller" <davem@davemloft.net>,
        "open list:HARDWARE RANDOM NUMBER GENERATOR CORE" 
        <linux-crypto@vger.kernel.org>
Subject: Re: [PATCH] crypto: ccree - enable CTS support in AES-XTS
Message-ID: <20190910012134.GA24413@gondor.apana.org.au>
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On Mon, Sep 09, 2019 at 03:38:02PM +0100, Ard Biesheuvel wrote:
>
> The blocksize is primarily used by the walking code to ensure that the
> input is a round multiple. In the XTS case, we can't blindly use the
> skcipher walk interface to go over the data anyway, since the last
> full block needs special handling as well.
> 
> So the answer is really that we had no reason to change it for the
> other drivers, and changing it here will trigger a failure in the
> testing code that compares against the generic implementations.

I think it should be changed because this is no different than
CTR where only the last block is allowed to be an arbitrary size.
Of course we should change everything in one go due to the testing
code.

This does raise the issue that we may be using blocksize in places
where we should be using chunksize instead, e.g., in algif_skcipher.

Cheers,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt