[PATCH 6.0 013/124] iio: health: afe4404: Fix oob read in afe4404_[read|write]_raw

Greg Kroah-Hartman
2022-12-05T19:23:09Z

From: Wei Yongjun <weiyongjun1@huawei.com>

[ Upstream commit fc92d9e3de0b2d30a3ccc08048a5fad533e4672b ]

KASAN report out-of-bounds read as follows:

BUG: KASAN: global-out-of-bounds in afe4404_read_raw+0x2ce/0x380
Read of size 4 at addr ffffffffc00e4658 by task cat/278

Call Trace:
afe4404_read_raw
iio_read_channel_info
dev_attr_show

The buggy address belongs to the variable:
afe4404_channel_leds+0x18/0xffffffffffffe9c0

This issue can be reproduce by singe command:

$ cat /sys/bus/i2c/devices/0-0058/iio\:device0/in_intensity6_raw

The array size of afe4404_channel_leds and afe4404_channel_offdacs
are less than channels, so access with chan->address cause OOB read
in afe4404_[read|write]_raw. Fix it by moving access before use them.

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/20221107152010.95937-1-weiyongjun@huaweicloud.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/iio/health/afe4404.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/iio/health/afe4404.c b/drivers/iio/health/afe4404.c
index dd7800159051..f03c466c9385 100644
--- a/drivers/iio/health/afe4404.c
+++ b/drivers/iio/health/afe4404.c
@@ -250,20 +250,20 @@ static int afe4404_read_raw(struct iio_dev *indio_dev,
int *val, int *val2, long mask)
{
struct afe4404_data *afe = iio_priv(indio_dev);
- unsigned int value_reg = afe4404_channel_values[chan->address];
- unsigned int led_field = afe4404_channel_leds[chan->address];
- unsigned int offdac_field = afe4404_channel_offdacs[chan->address];
+ unsigned int value_reg, led_field, offdac_field;
int ret;

switch (chan->type) {
case IIO_INTENSITY:
switch (mask) {
case IIO_CHAN_INFO_RAW:
+ value_reg = afe4404_channel_values[chan->address];
ret = regmap_read(afe->regmap, value_reg, val);
if (ret)
return ret;
return IIO_VAL_INT;
case IIO_CHAN_INFO_OFFSET:
+ offdac_field = afe4404_channel_offdacs[chan->address];
ret = regmap_field_read(afe->fields[offdac_field], val);
if (ret)
return ret;
@@ -273,6 +273,7 @@ static int afe4404_read_raw(struct iio_dev *indio_dev,
case IIO_CURRENT:
switch (mask) {
case IIO_CHAN_INFO_RAW:
+ led_field = afe4404_channel_leds[chan->address];
ret = regmap_field_read(afe->fields[led_field], val);
if (ret)
return ret;
@@ -295,19 +296,20 @@ static int afe4404_write_raw(struct iio_dev *indio_dev,
int val, int val2, long mask)
{
struct afe4404_data *afe = iio_priv(indio_dev);
- unsigned int led_field = afe4404_channel_leds[chan->address];
- unsigned int offdac_field = afe4404_channel_offdacs[chan->address];
+ unsigned int led_field, offdac_field;

switch (chan->type) {
case IIO_INTENSITY:
switch (mask) {
case IIO_CHAN_INFO_OFFSET:
+ offdac_field = afe4404_channel_offdacs[chan->address];
return regmap_field_write(afe->fields[offdac_field], val);
}
break;
case IIO_CURRENT:
switch (mask) {
case IIO_CHAN_INFO_RAW:
+ led_field = afe4404_channel_leds[chan->address];
return regmap_field_write(afe->fields[led_field], val);
}
break;
--
2.35.1