Re: [PATCH 16/22] crypto: ccree - add check for xts input length equal to zero

[Gilad Ben-Yossef]

On Fri, Aug 7, 2020 at 7:22 PM Andrei Botila <andrei.botila@xxxxxxxxxxx> wrote:
>
> From: Andrei Botila <andrei.botila@xxxxxxx>
>
> Standardize the way input lengths equal to 0 are handled in all skcipher
> algorithms. All the algorithms return 0 for input lengths equal to zero.
> This change has implications not only for xts(aes) but also for cts(cbc(aes))
> and cts(cbc(paes)).
>
> Cc: Gilad Ben-Yossef <gilad@xxxxxxxxxxxxx>
> Signed-off-by: Andrei Botila <andrei.botila@xxxxxxx>
> ---
>  drivers/crypto/ccree/cc_cipher.c | 11 ++++++-----
>  1 file changed, 6 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/crypto/ccree/cc_cipher.c b/drivers/crypto/ccree/cc_cipher.c
> index 076669dc1035..112bb8b4dce6 100644
> --- a/drivers/crypto/ccree/cc_cipher.c
> +++ b/drivers/crypto/ccree/cc_cipher.c
> @@ -912,17 +912,18 @@ static int cc_cipher_process(struct skcipher_request *req,
>
>         /* STAT_PHASE_0: Init and sanity checks */
>
> -       if (validate_data_size(ctx_p, nbytes)) {
> -               dev_dbg(dev, "Unsupported data size %d.\n", nbytes);
> -               rc = -EINVAL;
> -               goto exit_process;
> -       }
>         if (nbytes == 0) {
>                 /* No data to process is valid */
>                 rc = 0;
>                 goto exit_process;
>         }
>
> +       if (validate_data_size(ctx_p, nbytes)) {
> +               dev_dbg(dev, "Unsupported data size %d.\n", nbytes);
> +               rc = -EINVAL;
> +               goto exit_process;
> +       }
> +
>         if (ctx_p->fallback_on) {
>                 struct skcipher_request *subreq = skcipher_request_ctx(req);
>
> --
> 2.17.1
>

Acked-by: Gilad Ben-Yossef <gilad@xxxxxxxxxxxxx>

Thanks,
Gilad

-- 
Gilad Ben-Yossef
Chief Coffee Drinker

values of β will give rise to dom!