On Mon, 7 Nov 2022 15:20:10 +0000
Wei Yongjun <weiyongjun@xxxxxxxxxxxxxxx> wrote:
> From: Wei Yongjun <weiyongjun1@xxxxxxxxxx>
>
> 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@xxxxxxxxxx>
> Acked-by: Andrew Davis <afd@xxxxxx>
Applied to the fixes-togreg branch of iio.git.
Thanks,
Jonathan
> ---
> v2 -> v3: re-format backtraces
> v1 -> v2: also moved 'reg' to right before we use it
> added Acked-by
>
> 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 8fca787b2524..836da31b7e30 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;
