Re: [PATCH v5 08/10] crypto: safexcel - Simplify the check for a valid AES key

[Antoine Tenart]

On Mon, Aug 10, 2026 at 11:30:03AM +0200, Thomas Huth wrote:
> From: Thomas Huth <thuth@xxxxxxxxxx>
> 
> safexcel_aead_setkey() currently uses aes_expandkey() to check for a valid
> AES key, but then does not use the crypto_aes_ctx afterwards anymore,
> i.e. this is just a wasteful way of checking the key length, and thus
> aes_check_keylen() should be used instead.
> This also fixes a potential leak of sensitive data via the stack, since
> this function forgot to zeroize crypto_aes_ctx before returning to the
> caller.
> 
> Suggested-by: Antoine Tenart <atenart@xxxxxxxxxx>
> Signed-off-by: Thomas Huth <thuth@xxxxxxxxxx>

Acked-by: Antoine Tenart <atenart@xxxxxxxxxx>

Thanks!

> ---
>  drivers/crypto/inside-secure/safexcel_cipher.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/crypto/inside-secure/safexcel_cipher.c b/drivers/crypto/inside-secure/safexcel_cipher.c
> index a8349b684693e..f07d043c67d45 100644
> --- a/drivers/crypto/inside-secure/safexcel_cipher.c
> +++ b/drivers/crypto/inside-secure/safexcel_cipher.c
> @@ -407,7 +407,6 @@ static int safexcel_aead_setkey(struct crypto_aead *ctfm, const u8 *key,
>  	struct safexcel_cipher_ctx *ctx = crypto_tfm_ctx(tfm);
>  	struct safexcel_crypto_priv *priv = ctx->base.priv;
>  	struct crypto_authenc_keys keys;
> -	struct crypto_aes_ctx aes;
>  	int err = -EINVAL, i;
>  	const char *alg;
>  
> @@ -438,7 +437,7 @@ static int safexcel_aead_setkey(struct crypto_aead *ctfm, const u8 *key,
>  			goto badkey;
>  		break;
>  	case SAFEXCEL_AES:
> -		err = aes_expandkey(&aes, keys.enckey, keys.enckeylen);
> +		err = aes_check_keylen(keys.enckeylen);
>  		if (unlikely(err))
>  			goto badkey;
>  		break;
> -- 
> 2.55.0
>