[PATCH 5.15 014/120] iio: health: afe4403: Fix oob read in afe4403_read_raw

Greg Kroah-Hartman
2022-12-05T19:36:54Z

From: Wei Yongjun <weiyongjun1@huawei.com>

[ Upstream commit 58143c1ed5882c138a3cd2251a336fc8755f23d9 ]

KASAN report out-of-bounds read as follows:

BUG: KASAN: global-out-of-bounds in afe4403_read_raw+0x42e/0x4c0
Read of size 4 at addr ffffffffc02ac638 by task cat/279

Call Trace:
afe4403_read_raw
iio_read_channel_info
dev_attr_show

The buggy address belongs to the variable:
afe4403_channel_leds+0x18/0xffffffffffffe9e0

This issue can be reproduced by singe command:

$ cat /sys/bus/spi/devices/spi0.0/iio\:device0/in_intensity6_raw

The array size of afe4403_channel_leds is less than channels, so access
with chan->address cause OOB read in afe4403_read_raw. Fix it by moving
access before use it.

Fixes: b36e8257641a ("iio: health/afe440x: Use regmap fields")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Acked-by: Andrew Davis <afd@ti.com>
Link: https://lore.kernel.org/r/20221107151946.89260-1-weiyongjun@huaweicloud.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/iio/health/afe4403.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/health/afe4403.c b/drivers/iio/health/afe4403.c
index d4921385aaf7..b5f959bba422 100644
--- a/drivers/iio/health/afe4403.c
+++ b/drivers/iio/health/afe4403.c
@@ -245,14 +245,14 @@ static int afe4403_read_raw(struct iio_dev *indio_dev,
int *val, int *val2, long mask)
{
struct afe4403_data *afe = iio_priv(indio_dev);
- unsigned int reg = afe4403_channel_values[chan->address];
- unsigned int field = afe4403_channel_leds[chan->address];
+ unsigned int reg, field;
int ret;

switch (chan->type) {
case IIO_INTENSITY:
switch (mask) {
case IIO_CHAN_INFO_RAW:
+ reg = afe4403_channel_values[chan->address];
ret = afe4403_read(afe, reg, val);
if (ret)
return ret;
@@ -262,6 +262,7 @@ static int afe4403_read_raw(struct iio_dev *indio_dev,
case IIO_CURRENT:
switch (mask) {
case IIO_CHAN_INFO_RAW:
+ field = afe4403_channel_leds[chan->address];
ret = regmap_field_read(afe->fields[field], val);
if (ret)
return ret;
--
2.35.1