Re: [PATCH] tee: qcomtee: user: check the parameter count from the supplicant

[Jens Wiklander]

Hi,

On Wed, Aug 5, 2026 at 11:23 AM HyeongJun An <sammiee5311@xxxxxxxxx> wrote:
>
> The qcomtee_cb_params_to_args() walks the argument array QTEE asked for and
> indexes the parameter array the supplicant supplied, but it never looks at
> num_params. A supplicant that answers TEE_IOC_SUPPL_SEND with fewer
> parameters than the request needs makes that walk read past the end of the
> allocation.
>
> To fix this, reject a response that is too short, the way ureq_select()
> already does for the receive direction.
>
> Fixes: d6e290837e50 ("tee: add Qualcomm TEE driver")
> Assisted-by: Claude:claude-opus-5
> Signed-off-by: HyeongJun An <sammiee5311@xxxxxxxxx>
> ---
>  drivers/tee/qcomtee/user_obj.c | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/drivers/tee/qcomtee/user_obj.c b/drivers/tee/qcomtee/user_obj.c
> index 10452fcc7ccb..2a594ae299da 100644
> --- a/drivers/tee/qcomtee/user_obj.c
> +++ b/drivers/tee/qcomtee/user_obj.c
> @@ -507,6 +507,10 @@ static int qcomtee_cb_params_to_args(struct qcomtee_arg *u,
>  {
>         int i;
>
> +       /* Supplicant can not send fewer parameters than requested. */
> +       if (num_params < qcomtee_args_len(u))
> +               return -EINVAL;
> +
>         qcomtee_arg_for_each(i, u) {
>                 switch (u[i].type) {
>                 case QCOMTEE_ARG_TYPE_IB:
> --
> 2.43.0
>

Looks good. Amir, do you agree?

Cheers,
Jens