Re: [PATCH] firmware: arm_scmi: Relax BASE protocol sanity checks on protocol list
From: Michael Riesch
Date: Mon Jun 06 2022 - 08:59:21 EST
Hi Cristian,
On 5/23/22 19:15, Cristian Marussi wrote:
> Even though malformed replies from firmware must be treated carefully to
> avoid memory corruption Kernel side, some out-of-spec SCMI replies can
> be tolerated to avoid breaking existing deployed system, as long as they
> won't cause memory issues.
>
> Reported-by: Nicolas Frattaroli <frattaroli.nicolas@xxxxxxxxx>
> Cc: Etienne Carriere <etienne.carriere@xxxxxxxxxx>
> Cc: Sudeep Holla <sudeep.holla@xxxxxxx>
> Signed-off-by: Cristian Marussi <cristian.marussi@xxxxxxx>
Thanks a lot, without this fix the Mali G52 GPU won't probe on my RK3568
EVB1 in vanilla v5.19-rc1.
I guess this patch should have a Fixes: tag, right?
Would be great to have this in v5.19. AFAIC:
Acked-by: Michael Riesch <michael.riesch@xxxxxxxxxxxxxx>
Best regards,
Michael
> ---
> drivers/firmware/arm_scmi/base.c | 16 +++++++++++-----
> 1 file changed, 11 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/firmware/arm_scmi/base.c b/drivers/firmware/arm_scmi/base.c
> index 20fba7370f4e..d0ac96da1ddf 100644
> --- a/drivers/firmware/arm_scmi/base.c
> +++ b/drivers/firmware/arm_scmi/base.c
> @@ -221,11 +221,17 @@ scmi_base_implementation_list_get(const struct scmi_protocol_handle *ph,
> calc_list_sz = (1 + (loop_num_ret - 1) / sizeof(u32)) *
> sizeof(u32);
> if (calc_list_sz != real_list_sz) {
> - dev_err(dev,
> - "Malformed reply - real_sz:%zd calc_sz:%u\n",
> - real_list_sz, calc_list_sz);
> - ret = -EPROTO;
> - break;
> + dev_warn(dev,
> + "Malformed reply - real_sz:%zd calc_sz:%u (loop_num_ret:%d)\n",
> + real_list_sz, calc_list_sz, loop_num_ret);
> + /*
> + * Bail out if the expected list size is bigger than the
> + * total payload size of the received reply.
> + */
> + if (calc_list_sz > real_list_sz) {
> + ret = -EPROTO;
> + break;
> + }
> }
>
> for (loop = 0; loop < loop_num_ret; loop++)