iio: adc: rockchip_saradc: fix information leak in triggered buffer

commit 38724591364e1e3b278b4053f102b49ea06ee17c upstream.

The 'data' local struct 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 struct to zero before using it to avoid pushing
uninitialized information to userspace.

Cc: [email protected]
Fixes: 4e130dc ("iio: adc: rockchip_saradc: Add support iio buffers")
Signed-off-by: Javier Carrasco <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jonathan Cameron <[email protected]>
Signed-off-by: Bin Lan <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: javiercarrascocruz

drivers/iio/adc/rockchip_saradc.c

@@ -270,6 +270,8 @@ static irqreturn_t rockchip_saradc_trigger_handler(int irq, void *p)
 	int ret;
 	int i, j = 0;
 
+	memset(&data, 0, sizeof(data));
+
 	mutex_lock(&i_dev->mlock);
 
 	for_each_set_bit(i, i_dev->active_scan_mask, i_dev->masklength) {