Re: [PATCH 11/18] crypto: dh - introduce support for ephemeral key generation to hpre driver

[Stephan Müller]

Am Mittwoch, 1. Dezember 2021, 01:48:51 CET schrieb Nicolai Stange:

Hi Nicolai,

> A previous patch made the dh-generic implementation's ->set_secret() to
> generate an ephemeral key in case the input ->key_size is zero, just in
> analogy with ecdh. Make the hpre crypto driver's DH implementation to
> behave consistently by doing the same.
> 
> Signed-off-by: Nicolai Stange <nstange@xxxxxxx>
> ---
>  drivers/crypto/hisilicon/hpre/hpre_crypto.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/drivers/crypto/hisilicon/hpre/hpre_crypto.c
> b/drivers/crypto/hisilicon/hpre/hpre_crypto.c index
> a032c192ef1d..02ca79e263f1 100644
> --- a/drivers/crypto/hisilicon/hpre/hpre_crypto.c
> +++ b/drivers/crypto/hisilicon/hpre/hpre_crypto.c
> @@ -701,11 +701,20 @@ static int hpre_dh_set_secret(struct crypto_kpp *tfm,
> const void *buf, {
>  	struct hpre_ctx *ctx = kpp_tfm_ctx(tfm);
>  	struct dh params;
> +	char key[CRYPTO_DH_MAX_PRIVKEY_SIZE];
>  	int ret;
> 
>  	if (crypto_dh_decode_key(buf, len, &params) < 0)
>  		return -EINVAL;
> 
> +	if (!params.key_size) {

dto.

> +		ret = crypto_dh_gen_privkey(params.group_id, key,
> +					    &params.key_size);
> +		if (ret)
> +			return ret;
> +		params.key = key;
> +	}
> +
>  	/* Free old secret if any */
>  	hpre_dh_clear_ctx(ctx, false);
> 
> @@ -716,6 +725,8 @@ static int hpre_dh_set_secret(struct crypto_kpp *tfm,
> const void *buf, memcpy(ctx->dh.xa_p + (ctx->key_sz - params.key_size),
> params.key, params.key_size);
> 
> +	memzero_explicit(key, sizeof(key));
> +
>  	return 0;
> 
>  err_clear_ctx:


Ciao
Stephan