iio: imu: st_lsm6dsx: Avoid potential array overflow in st_lsm6dsx_set_odr()

[ 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@tsinghua.edu.cn>
Signed-off-by: Teng Qi <starmiku1207184332@gmail.com>
Acked-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/20211011114003.976221-1-starmiku1207184332@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c
index 057a4b0100106bdc2e216b11339ffcf1b9371476..8850da8e25d69a1f08726f2168924027c0d5373e 100644 (file)
--- a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c
+++ b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c
@@ -1015,6 +1015,8 @@ static int st_lsm6dsx_set_odr(struct st_lsm6dsx_sensor *sensor, u16 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:
@@ -1040,8 +1042,8 @@ static int st_lsm6dsx_set_odr(struct st_lsm6dsx_sensor *sensor, u16 req_odr)
                }
                break;
        }
-       default:
-               break;
+       default: /* should never occur */
+               return -EINVAL;
        }
 
        if (req_odr > 0) {