Re: [PATCH] iio: imu: bmi323: Fix potential out-of-bounds access of bmi323_hw[]

[David Lechner <dlechner@baylibre.com>]

On 3/27/26 5:32 AM, gerben@altlinux.org wrote:
> From: Denis Rastyogin <gerben@altlinux.org>
> 
> The bmi323_channels[] array defines a channel with chan->type =
> IIO_TEMP and enables the IIO_CHAN_INFO_SCALE mask. As a result,
> bmi323_write_raw() may be called for this channel. However,
> bmi323_iio_to_sensor() returns -EINVAL for IIO_TEMP, and if this
> value is not validated, it can lead to an out-of-bounds access
> when used as an array index.
> 
> A similar case is properly handled in bmi323_read_raw() and does
> not result in an error.
> 
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
> 
> Fixes: 8a636db3aa57 ("iio: imu: Add driver for BMI323 IMU")
> Signed-off-by: Denis Rastyogin <gerben@altlinux.org>
> ---
>  drivers/iio/imu/bmi323/bmi323_core.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/iio/imu/bmi323/bmi323_core.c b/drivers/iio/imu/bmi323/bmi323_core.c
> index 6bcb9a436581..64ead4f667e0 100644
> --- a/drivers/iio/imu/bmi323/bmi323_core.c
> +++ b/drivers/iio/imu/bmi323/bmi323_core.c
> @@ -1713,6 +1713,8 @@ static int bmi323_write_raw(struct iio_dev *indio_dev,
>  		iio_device_release_direct(indio_dev);
>  		return ret;
>  	case IIO_CHAN_INFO_SCALE:
> +		if (chan->type == IIO_TEMP)
> +			return -EINVAL;
>  		if (!iio_device_claim_direct(indio_dev))
>  			return -EBUSY;
>  		ret = bmi323_set_scale(data, bmi323_iio_to_sensor(chan->type),

This is OK, but why not check and propagate the error return?

 	case IIO_CHAN_INFO_SCALE:
		ret = bmi323_iio_to_sensor(chan->type);
		if (ret < 0)
			return ret;

  		if (!iio_device_claim_direct(indio_dev))
  			return -EBUSY;
  		ret = bmi323_set_scale(data, ret, val, val2);
		...

And even if we shouldn't hit the error in other case statements,
it seems like it would be good practice to still check for error
there too.