Re: [PATCH AUTOSEL 5.15 66/82] iio: imu: st_lsm6dsx: Avoid potential array overflow in st_lsm6dsx_set_odr()
From: Jonathan Cameron <jic23@kernel.org>
Date: 2021-11-12 17:28:39
Also in:
linux-iio, lkml
On Tue, 9 Nov 2021 17:16:24 -0500 Sasha Levin [off-list ref] wrote:
From: Teng Qi <redacted>
[ 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 <redacted>
Signed-off-by: Teng Qi <redacted>
Acked-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/20211011114003.976221-1-starmiku1207184332@gmail.com (local)
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>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
quoted hunk ↗ jump to hunk
--- 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) {