[PATCH 08/15] iio: light: apds9306: push events to the IIO device

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

From: Josef Bacik <josef@toxicpanda.com>

Reading a light channel while threshold events are enabled can push an
event through a pointer that is not an IIO device, corrupting memory or
crashing the kernel.

apds9306_read_data() derives indio_dev with dev_to_iio_dev(data->dev),
but data->dev is the I2C client's device, not the device embedded in
struct iio_dev. When the status register read by the poll loop has
APDS9306_ALS_INT_STAT_MASK set, the bogus pointer is passed to
iio_push_event() and iio_get_time_ns(), which dereference the event
interface and clock id of a structure that does not exist.

The bug was found by code inspection and has not been reproduced.

Fix by taking the IIO device from the I2C client's driver data, which
probe sets with i2c_set_clientdata().

Fixes: 620d1e6c7a3f ("iio: light: Add support for APDS9306 Light Sensor")
Cc: stable <stable@kernel.org>
Cc: Subhajit Ghosh <subhajit.ghosh@tweaklogic.com>
Cc: David Lechner <dlechner@baylibre.com>
Cc: "Nuno Sá" <nuno.sa@analog.com>
Cc: Andy Shevchenko <andy@kernel.org>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/iio/light/apds9306.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iio/light/apds9306.c b/drivers/iio/light/apds9306.c
index 7dd41136734f..79138422221d 100644
--- a/drivers/iio/light/apds9306.c
+++ b/drivers/iio/light/apds9306.c
@@ -462,7 +462,7 @@ static int apds9306_power_state(struct apds9306_data *data, bool state)
 static int apds9306_read_data(struct apds9306_data *data, int *val, int reg)
 {
 	struct device *dev = data->dev;
-	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
 	struct apds9306_regfields *rf = &data->rf;
 	u64 ev_code;
 	int ret, delay, intg_time, intg_time_idx, repeat_rate_idx, int_src;

-- 
2.56.0