Re: [PATCH 3/6] crypto: api - avoid VLA use

From: Herbert Xu
Date: Sun Apr 08 2018 - 05:22:31 EST


On Sun, Apr 08, 2018 at 11:07:12AM +0200, Salvatore Mesoraca wrote:
>
> > This check should be done when the algorithm is registered. Perhaps
> > crypto_check_alg.
>
> Please correct me if I'm wrong:
> isn't crypto_check_alg invoked also during hashing algorithm registration?
> In this patch-set I'm dealing only with ciphers, because the maximum
> block size (16)
> is relatively small and it's also the most common block size with
> ciphers (maybe I should
> have explicitly referenced ciphers in the macro names, my bad).
> I don't think that it would be OK to use a similar approach for hashes
> too, because some
> of them have block size >= 1024 bytes.

Yes we want to make it for ciphers only even if we move it to
crypto_check_alg.

For a legacy type like cipher cou can do it by

if (!alg->cra_type && (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) ==
CRYPTO_ALG_TYPE_CIPHER)
do_cipher_specific_check();

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