Re: [PATCH v5 10/10] crypto: eip93 - Simplify the check for a valid AES key

[Antoine Tenart]

On Mon, Aug 10, 2026 at 11:30:05AM +0200, Thomas Huth wrote:
> From: Thomas Huth <thuth@xxxxxxxxxx>
> 
> eip93_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>

Reviewed-by: Antoine Tenart <atenart@xxxxxxxxxx>

> ---
>  drivers/crypto/inside-secure/eip93/eip93-aead.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/crypto/inside-secure/eip93/eip93-aead.c b/drivers/crypto/inside-secure/eip93/eip93-aead.c
> index 2bbd0af7b0e0e..0b7a899b14d76 100644
> --- a/drivers/crypto/inside-secure/eip93/eip93-aead.c
> +++ b/drivers/crypto/inside-secure/eip93/eip93-aead.c
> @@ -92,7 +92,6 @@ static int eip93_aead_setkey(struct crypto_aead *ctfm, const u8 *key,
>  	struct crypto_tfm *tfm = crypto_aead_tfm(ctfm);
>  	struct eip93_crypto_ctx *ctx = crypto_tfm_ctx(tfm);
>  	struct crypto_authenc_keys keys;
> -	struct crypto_aes_ctx aes;
>  	struct sa_record *sa_record = ctx->sa_record;
>  	u32 nonce = 0;
>  	int ret;
> @@ -126,7 +125,7 @@ static int eip93_aead_setkey(struct crypto_aead *ctfm, const u8 *key,
>  
>  		break;
>  	case EIP93_ALG_AES:
> -		ret = aes_expandkey(&aes, keys.enckey, keys.enckeylen);
> +		ret = aes_check_keylen(keys.enckeylen);
>  		if (ret)
>  			return ret;
>  
> -- 
> 2.55.0
>