Re: [PATCH v2] iio: imu: st_lsm6dsx: Fix an array overflow in st_lsm6dsx_set_odr()

[Lorenzo Bianconi <lorenzo@kernel.org>]

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> The length of hw->settings->odr_table is 2 and ref_sensor->id is an enum
> variable whose value is between 0 and 5.
> However, the value ST_LSM6DSX_ID_MAX (i.e. 5) is not catched properly in
>  switch (sensor->id) {
> 
> If ref_sensor->id is ST_LSM6DSX_ID_MAX, an array overflow will ocurrs in
> function st_lsm6dsx_check_odr():
>   odr_table = &sensor->hw->settings->odr_table[sensor->id];
> 
> and in function st_lsm6dsx_set_odr():
>   reg = &hw->settings->odr_table[ref_sensor->id].reg;
> 
> To fix this array overflow, handle ST_LSM6DSX_ID_GYRO explicitly and 
> return -EINVAL for the default case.
> 
> Reported-by: TOTE Robot <oslab@tsinghua.edu.cn>
> Signed-off-by: Teng Qi <starmiku1207184332@gmail.com>

Acked-by: Lorenzo Bianconi <lorenzo@kernel.org>
> 
> ---
> v2:
> * explicitly handle ST_LSM6DSX_ID_GYRO and return -EINVAL for the default
> case instead of adding an if statement behind the switch statement.
>   Thank Lars-Peter Clausen for helpful and friendly advice.
> 
> ---
>  drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c
> index db45f1fc0b81..8dbf744c5651 100644
> --- a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c
> +++ b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c
> @@ -1279,6 +1279,8 @@ st_lsm6dsx_set_odr(struct st_lsm6dsx_sensor *sensor, u32 req_odr)
>  	int err;
>  
>  	switch (sensor->id) {
> +	case ST_LSM6DSX_ID_GYRO:
> +		break;
>  	case ST_LSM6DSX_ID_EXT0:
>  	case ST_LSM6DSX_ID_EXT1:
>  	case ST_LSM6DSX_ID_EXT2:
> @@ -1304,8 +1306,8 @@ st_lsm6dsx_set_odr(struct st_lsm6dsx_sensor *sensor, u32 req_odr)
>  		}
>  		break;
>  	}
> -	default:
> -		break;
> +	default: /* should never occur */
> +		return -EINVAL;
>  	}
>  
>  	if (req_odr > 0) {
> -- 
> 2.25.1
> 

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