Re: [PATCH] tee: fix uninitialized pointers with free attr

[Jens Wiklander]

Hi,

On Wed, Nov 5, 2025 at 3:20 PM Ally Heev <allyheev@xxxxxxxxx> wrote:
>
> Uninitialized pointers with `__free` attribute can cause undefined
> behaviour as the memory assigned(randomly) to the pointer is freed
> automatically when the pointer goes out of scope
>
> tee doesn't have any bugs related to this as of now, but
> it is better to initialize and assign pointers with `__free` attr
> in one statement to ensure proper scope-based cleanup
>
> Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> Closes: https://lore.kernel.org/all/aPiG_F5EBQUjZqsl@stanley.mountain/
> Signed-off-by: Ally Heev <allyheev@xxxxxxxxx>
> ---
>  drivers/tee/qcomtee/call.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/tee/qcomtee/call.c b/drivers/tee/qcomtee/call.c
> index ac134452cc9cfd384c28d41547545f2c5748d86c..8b7b4decddd8d1811dc0a7cc46a4a4fbada45526 100644
> --- a/drivers/tee/qcomtee/call.c
> +++ b/drivers/tee/qcomtee/call.c
> @@ -645,12 +645,13 @@ static void qcomtee_get_version(struct tee_device *teedev,
>  static void qcomtee_get_qtee_feature_list(struct tee_context *ctx, u32 id,
>                                           u32 *version)
>  {
> -       struct qcomtee_object_invoke_ctx *oic __free(kfree);
>         struct qcomtee_object *client_env, *service;
>         struct qcomtee_arg u[3] = { 0 };
>         int result;
>
> -       oic = qcomtee_object_invoke_ctx_alloc(ctx);
> +       struct qcomtee_object_invoke_ctx *oic __free(kfree) =
> +               qcomtee_object_invoke_ctx_alloc(ctx);

Can we zero-initialize oic at its original location instead? Doing it
here looks messy.

Thanks,
Jens

> +
>         if (!oic)
>                 return;
>
>
> ---
> base-commit: c9cfc122f03711a5124b4aafab3211cf4d35a2ac
> change-id: 20251105-aheev-uninitialized-free-attr-tee-0221e45ec5a2
>
> Best regards,
> --
> Ally Heev <allyheev@xxxxxxxxx>
>