Re: [PATCH v7 02/11] crypto: akcipher - check the presence of callback before the call

[Herbert Xu]

On Fri, Mar 01, 2019 at 08:59:09PM +0300, Vitaly Chikunov wrote:
> Because with introduction of EC-RDSA and change in workings of RSA in
> regard to sign/verify, akcipher could have not all callbacks defined,
> check the presence of callbacks before calling them to increase
> robustness.
> 
> Signed-off-by: Vitaly Chikunov <vt@xxxxxxxxxxxx>
> ---
>  include/crypto/akcipher.h | 25 ++++++++++++++++---------
>  1 file changed, 16 insertions(+), 9 deletions(-)
> 
> diff --git a/include/crypto/akcipher.h b/include/crypto/akcipher.h
> index 2d690494568c..f537fad1989f 100644
> --- a/include/crypto/akcipher.h
> +++ b/include/crypto/akcipher.h
> @@ -268,7 +268,10 @@ static inline unsigned int crypto_akcipher_maxsize(struct crypto_akcipher *tfm)
>  {
>  	struct akcipher_alg *alg = crypto_akcipher_alg(tfm);
>  
> -	return alg->max_size(tfm);
> +	if (alg->max_size)
> +		return alg->max_size(tfm);
> +	else
> +		return 0;
>  }

Please do these checks at registration time instead and provide
default implementations as needed.

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