Re: [PATCH v2 3/4] venus: hfi: add checks to handle capabilities from firmware

[Bryan O'Donoghue <bryan.odonoghue@linaro.org>]

On 10/08/2023 03:25, Vikash Garodia wrote:
> The hfi parser, parses the capabilities received from venus firmware and
> copies them to core capabilities. Consider below api, for example,
> fill_caps - In this api, caps in core structure gets updated with the
> number of capabilities received in firmware data payload. If the same api
> is called multiple times, there is a possibility of copying beyond the max
> allocated size in core caps.
> Similar possibilities in fill_raw_fmts and fill_profile_level functions.
> 
> Cc: stable@vger.kernel.org
> Fixes: 1a73374a04e5 ("media: venus: hfi_parser: add common capability parser")
> Signed-off-by: Vikash Garodia <quic_vgarodia@quicinc.com>
> ---
>   drivers/media/platform/qcom/venus/hfi_parser.c | 12 ++++++++++++
>   1 file changed, 12 insertions(+)
> 
> diff --git a/drivers/media/platform/qcom/venus/hfi_parser.c b/drivers/media/platform/qcom/venus/hfi_parser.c
> index 6cf74b2..9d6ba22 100644
> --- a/drivers/media/platform/qcom/venus/hfi_parser.c
> +++ b/drivers/media/platform/qcom/venus/hfi_parser.c
> @@ -86,6 +86,9 @@ static void fill_profile_level(struct hfi_plat_caps *cap, const void *data,
>   {
>   	const struct hfi_profile_level *pl = data;
>   
> +	if (cap->num_pl + num >= HFI_MAX_PROFILE_COUNT)
> +		return;
> +
>   	memcpy(&cap->pl[cap->num_pl], pl, num * sizeof(*pl));
>   	cap->num_pl += num;
>   }

Why append and discard though ?

Couldn't we reset/reinitalise the relevant indexes in hfi_sys_init_done() ?

Can subsequent notifications from the firmware give a new capability set 
? Presumably not.

IMO though instead of throwing away the new data, we should throw away 
the old data, no ?

---
bod