iio: adc: ti-ads8688: fix information leak in triggered buffer

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: 61fa5dfa5f52 ("iio: adc: ti-ads8688: Fix alignment of buffer in iio_push_to_buffers_with_timestamp()")
Signed-off-by: Javier Carrasco <javier.carrasco.cruz@gmail.com>
Link: https://patch.msgid.link/20241125-iio_memset_scan_holes-v1-8-0cb6e98d895c@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/adc/ti-ads8688.c b/drivers/iio/adc/ti-ads8688.c
index 9b1814f1965a37f660ce60f38c531870b9048e00..a31658b760a4ae79d1504d6af288470d0cc6d348 100644 (file)
--- a/drivers/iio/adc/ti-ads8688.c
+++ b/drivers/iio/adc/ti-ads8688.c
@@ -381,7 +381,7 @@ static irqreturn_t ads8688_trigger_handler(int irq, void *p)
        struct iio_poll_func *pf = p;
        struct iio_dev *indio_dev = pf->indio_dev;
        /* Ensure naturally aligned timestamp */
-       u16 buffer[ADS8688_MAX_CHANNELS + sizeof(s64)/sizeof(u16)] __aligned(8);
+       u16 buffer[ADS8688_MAX_CHANNELS + sizeof(s64)/sizeof(u16)] __aligned(8) = { };
        int i, j = 0;
 
        iio_for_each_active_channel(indio_dev, i) {