Re: [PATCH v2 03/28] spi: s3c64xx: avoid possible negative array index

[Sam Protsenko <semen.protsenko@xxxxxxxxxx>]

On Thu, Jan 25, 2024 at 8:50 AM Tudor Ambarus <tudor.ambarus@xxxxxxxxxx> wrote:
>
> The platform id is used as an index into the fifo_lvl_mask array.
> Platforms can come with a negative device ID, PLATFORM_DEVID_NONE (-1),
> thus we risked a negative array index. Catch such cases and fail to
> probe.
>
> Fixes: 2b90807549e5 ("spi: s3c64xx: add device tree support")
> Signed-off-by: Tudor Ambarus <tudor.ambarus@xxxxxxxxxx>
> ---
>  drivers/spi/spi-s3c64xx.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c
> index 2b5bb7604526..c3176a510643 100644
> --- a/drivers/spi/spi-s3c64xx.c
> +++ b/drivers/spi/spi-s3c64xx.c
> @@ -1189,6 +1189,9 @@ static int s3c64xx_spi_probe(struct platform_device *pdev)
>                                              "Failed to get alias id\n");
>                 sdd->port_id = ret;
>         } else {
> +               if (pdev->id < 0)

I'd add { } braces around this block, but that's a matter of taste.
Also, I'm not sure why do we still want to handle !of_node case for
drivers like these at all: there is no mfd case for this driver, and
board files are long gone; it seems to be OF only driver in a sense,
from its users POV. Anyways, LGTM:

Reviewed-by: Sam Protsenko <semen.protsenko@xxxxxxxxxx>

> +                       return dev_err_probe(&pdev->dev, -EINVAL,
> +                                            "Negative platform ID is not allowed\n");
>                 sdd->port_id = pdev->id;
>         }
>
> --
> 2.43.0.429.g432eaa2c6b-goog
>