iio: imu: kmx61: fix information leak in triggered buffer

BugLink: https://bugs.launchpad.net/bugs/2106770

commit 6ae0531 upstream.

The 'buffer' local array is used to push data to user space from a
triggered buffer, but it does not set values for inactive channels, as
it only uses iio_for_each_active_channel() to assign new values.

Initialize the array to zero before using it to avoid pushing
uninitialized information to userspace.

Cc: stable@vger.kernel.org
Fixes: c3a23ec ("iio: imu: kmx61: Add support for data ready triggers")
Signed-off-by: Javier Carrasco <javier.carrasco.cruz@gmail.com>
Link: https://patch.msgid.link/20241125-iio_memset_scan_holes-v1-5-0cb6e98d895c@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CVE-2024-57908
Signed-off-by: Manuel Diewald <manuel.diewald@canonical.com>
Signed-off-by: Mehmet Basaran <mehmet.basaran@canonical.com>

Author: javiercarrascocruz

drivers/iio/imu/kmx61.c

@@ -1192,7 +1192,7 @@ static irqreturn_t kmx61_trigger_handler(int irq, void *p)
 	struct kmx61_data *data = kmx61_get_data(indio_dev);
 	int bit, ret, i = 0;
 	u8 base;
-	s16 buffer[8];
+	s16 buffer[8] = { };
 
 	if (indio_dev == data->acc_indio_dev)
 		base = KMX61_ACC_XOUT_L;