Re: [PATCH] x86/sgx: Use SHA-256 library API instead of crypto_shash API

[Jarkko Sakkinen <jarkko@kernel.org>]

On Mon, Apr 28, 2025 at 12:19:50PM -0700, Dave Hansen wrote:
> On 4/28/25 11:38, Eric Biggers wrote:
> > -static int sgx_get_key_hash(const void *modulus, void *hash)
> > -{
> > -	struct crypto_shash *tfm;
> > -	int ret;
> > -
> > -	tfm = crypto_alloc_shash("sha256", 0, CRYPTO_ALG_ASYNC);
> > -	if (IS_ERR(tfm))
> > -		return PTR_ERR(tfm);
> > -
> > -	ret = __sgx_get_key_hash(tfm, modulus, hash);
> > -
> > -	crypto_free_shash(tfm);
> > -	return ret;
> > -}
> 
> Let's just say, theoretically, that there was some future hardware that
> also supported SHA384.  There doesn't seem to be a SHA-384 library API.
> 
> Would you leave the crypto_shash() in place if that were to be
> happening? Theoretically of course.

I don't see any reason why SHA-384 could not be added in order to
support a CPU feature.

BR, Jarkko