[PATCH] iio: gyro: bmg160: bail out when bandwidth/filter is not in table

[Stepan Ionichev <sozdayvek@gmail.com>]

bmg160_get_filter() walks bmg160_samp_freq_table[] looking for the
entry matching the bw_bits value read from the chip:

	for (i = 0; i < ARRAY_SIZE(bmg160_samp_freq_table); ++i) {
		if (bmg160_samp_freq_table[i].bw_bits == bw_bits)
			break;
	}
	*val = bmg160_samp_freq_table[i].filter;

If no entry matches, i ends up equal to the array size and the next
line reads one slot past the end. bmg160_set_filter() has the same
shape, driven by 'val' instead of bw_bits.

smatch flags both:

  drivers/iio/gyro/bmg160_core.c:204 bmg160_get_filter() error:
  buffer overflow 'bmg160_samp_freq_table' 7 <= 7
  drivers/iio/gyro/bmg160_core.c:222 bmg160_set_filter() error:
  buffer overflow 'bmg160_samp_freq_table' 7 <= 7

Return -EINVAL when no entry matches.

Signed-off-by: Stepan Ionichev <sozdayvek@gmail.com>
---
 drivers/iio/gyro/bmg160_core.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/iio/gyro/bmg160_core.c b/drivers/iio/gyro/bmg160_core.c
index 38394b5f3..58963f3ea 100644
--- a/drivers/iio/gyro/bmg160_core.c
+++ b/drivers/iio/gyro/bmg160_core.c
@@ -201,6 +201,9 @@ static int bmg160_get_filter(struct bmg160_data *data, int *val)
 			break;
 	}
 
+	if (i == ARRAY_SIZE(bmg160_samp_freq_table))
+		return -EINVAL;
+
 	*val = bmg160_samp_freq_table[i].filter;
 
 	return ret ? ret : IIO_VAL_INT;
@@ -218,6 +221,9 @@ static int bmg160_set_filter(struct bmg160_data *data, int val)
 			break;
 	}
 
+	if (i == ARRAY_SIZE(bmg160_samp_freq_table))
+		return -EINVAL;
+
 	ret = regmap_write(data->regmap, BMG160_REG_PMU_BW,
 			   bmg160_samp_freq_table[i].bw_bits);
 	if (ret < 0) {
-- 
2.43.0