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

[Nathan Hebert]

On Wed, Jul 26, 2023 at 9:35 PM Vikash Garodia
<quic_vgarodia@xxxxxxxxxxx> 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@xxxxxxxxxxxxxxx
> Fixes: 1a73374a04e5 ("media: venus: hfi_parser: add common capability parser")
> Signed-off-by: Vikash Garodia <quic_vgarodia@xxxxxxxxxxx>
> ---
>  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..ec73cac 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 > HFI_MAX_PROFILE_COUNT)
> +               return;
> +
This check does not fully prevent out of bounds writes. Should the
return condition be on |cap->num_pl + num > HFI_MAX_PROFILE_COUNT|, so
the last byte won't be written past the end of the array?

Similarly for the patches to |fill_caps| and |fill_raw_fmts|.
>         memcpy(&cap->pl[cap->num_pl], pl, num * sizeof(*pl));
>         cap->num_pl += num;
>  }
> @@ -111,6 +114,9 @@ fill_caps(struct hfi_plat_caps *cap, const void *data, unsigned int num)
>  {
>         const struct hfi_capability *caps = data;
>
> +       if (cap->num_caps > MAX_CAP_ENTRIES)
> +               return;
> +
>         memcpy(&cap->caps[cap->num_caps], caps, num * sizeof(*caps));
>         cap->num_caps += num;
>  }
> @@ -137,6 +143,9 @@ static void fill_raw_fmts(struct hfi_plat_caps *cap, const void *fmts,
>  {
>         const struct raw_formats *formats = fmts;
>
> +       if (cap->num_fmts > MAX_FMT_ENTRIES)
> +               return;
> +
>         memcpy(&cap->fmts[cap->num_fmts], formats, num_fmts * sizeof(*formats));
>         cap->num_fmts += num_fmts;
>  }
> @@ -159,6 +168,9 @@ parse_raw_formats(struct venus_core *core, u32 codecs, u32 domain, void *data)
>                 rawfmts[i].buftype = fmt->buffer_type;
>                 i++;
>
> +               if (i >= MAX_FMT_ENTRIES)
> +                       return;
> +
>                 if (pinfo->num_planes > MAX_PLANES)
>                         break;
>
> --
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project
>

Best regards,
Nathan Hebert