[PATCH 2/2] tee: optee: don't enumerate services if there ain't any

[Patrice CHOTARD]

On 11/29/23 13:37, Etienne Carriere wrote:
> Change optee driver service enumeration to not enumerate (and
> allocate a zero sized shared memory buffer) when OP-TEE
> reports that there is no service to enumerate.
> 
> This change fixes an existing issue that occurs when the such zero
> sized shared memory buffer allocated from malloc() has a physical
> address of offset 0 of a physical 4kB page. In such case, OP-TEE
> secure world refuses to register the zero-sized shared memory
> area and makes U-Boot optee service enumeration to fail.
> 
> Fixes: 94ccfb78a4d6 ("drivers: tee: optee: discover OP-TEE services")
> Signed-off-by: Etienne Carriere <etienne.carriere at foss.st.com>
> ---
>  drivers/tee/optee/core.c | 10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/tee/optee/core.c b/drivers/tee/optee/core.c
> index 5308dd58ce..47f845cffe 100644
> --- a/drivers/tee/optee/core.c
> +++ b/drivers/tee/optee/core.c
> @@ -139,6 +139,11 @@ static int enum_services(struct udevice *dev, struct tee_shm **shm, size_t *coun
>  	if (ret)
>  		return ret;
>  
> +	if (!shm_size) {
> +		*count = 0;
> +		return 0;
> +	}
> +
>  	ret = tee_shm_alloc(dev, shm_size, 0, shm);
>  	if (ret) {
>  		dev_err(dev, "Failed to allocated shared memory: %d\n", ret);
> @@ -185,14 +190,15 @@ static int bind_service_drivers(struct udevice *dev)
>  
>  	ret = enum_services(dev, &service_list, &service_count, tee_sess,
>  			    PTA_CMD_GET_DEVICES);
> -	if (!ret)
> +	if (!ret && service_count)
>  		ret = bind_service_list(dev, service_list, service_count);
>  
>  	tee_shm_free(service_list);
> +	service_list = NULL;
>  
>  	ret2 = enum_services(dev, &service_list, &service_count, tee_sess,
>  			     PTA_CMD_GET_DEVICES_SUPP);
> -	if (!ret2)
> +	if (!ret2 && service_count)
>  		ret2 = bind_service_list(dev, service_list, service_count);
>  
>  	tee_shm_free(service_list);
Reviewed-by: Patrice Chotard <patrice.chotard at foss.st.com>

Thanks
Patrice