[PATCH 3/3] iio: imu: adis16550: fix stack leak in trigger handler

[Greg Kroah-Hartman]

adis16550_trigger_handler() declares the scan data array on the stack
without initializing it.  The memcpy() at the bottom fills only the
first 28 bytes (TEMP + 6 channels of GYRO/ACCEL data), and
iio_push_to_buffers_with_timestamp() writes the s64 timestamp at the
8-byte-aligned offset 32.  Bytes 28-31 remain uninitialized stack data
which leaks to userspace on ever trigger.

Fix this all by just zero-initializing the structure on the stack.

Cc: Lars-Peter Clausen <lars@xxxxxxxxxx>
Cc: Michael Hennerich <Michael.Hennerich@xxxxxxxxxx>
Cc: Jonathan Cameron <jic23@xxxxxxxxxx>
Cc: David Lechner <dlechner@xxxxxxxxxxxx>
Cc: "Nuno Sá" <nuno.sa@xxxxxxxxxx>
Cc: Andy Shevchenko <andy@xxxxxxxxxx>
Fixes: e4570f4bb231 ("iio: imu: adis16550: align buffers for timestamp")
Cc: stable <stable@xxxxxxxxxx>
Assisted-by: gregkh_clanker_t1000
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/iio/imu/adis16550.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iio/imu/adis16550.c b/drivers/iio/imu/adis16550.c
index 1f2af506f4bd..75679612052f 100644
--- a/drivers/iio/imu/adis16550.c
+++ b/drivers/iio/imu/adis16550.c
@@ -836,7 +836,7 @@ static irqreturn_t adis16550_trigger_handler(int irq, void *p)
 	u16 dummy;
 	bool valid;
 	struct iio_poll_func *pf = p;
-	__be32 data[ADIS16550_MAX_SCAN_DATA] __aligned(8);
+	__be32 data[ADIS16550_MAX_SCAN_DATA] __aligned(8) = { };
 	struct iio_dev *indio_dev = pf->indio_dev;
 	struct adis16550 *st = iio_priv(indio_dev);
 	struct adis *adis = iio_device_get_drvdata(indio_dev);
-- 
2.53.0