On Tue, 9 Nov 2021 17:16:24 -0500
Sasha Levin <sashal@xxxxxxxxxx> wrote:
> From: Teng Qi <starmiku1207184332@xxxxxxxxx>
>
> [ Upstream commit 94be878c882d8d784ff44c639bf55f3b029f85af ]
>
> 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 caught 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 avoid this array overflow, handle ST_LSM6DSX_ID_GYRO explicitly and
> return -EINVAL for the default case.
>
> The enum value ST_LSM6DSX_ID_MAX is only present as an easy way to check
> the limit and as such is never used, however this is not locally obvious.
>
> Reported-by: TOTE Robot <oslab@xxxxxxxxxxxxxxx>
> Signed-off-by: Teng Qi <starmiku1207184332@xxxxxxxxx>
> Acked-by: Lorenzo Bianconi <lorenzo@xxxxxxxxxx>
> Link: https://lore.kernel.org/r/20211011114003.976221-1-starmiku1207184332@xxxxxxxxx
> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
This is really just noise for stable. There wasn't a bug here though
the change is doing some hardening and improving local readability by
saving anyone having to confirm it can't occur by looking at the enum
values.
I don't mind it going into stable though if others feel it's worthwhile.
Jonathan
> ---
> 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 db45f1fc0b817..8dbf744c5651f 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) {
