[PATCH v3] gpiolib: cdev: zero padding during conversion to gpioline_info_changed

[Gabriel Knezek <gabeknez@xxxxxxxxxxxxxxxxxxx>]

When userspace requests a GPIO v1 line info changed event,
lineinfo_watch_read() populates and returns the gpioline_info_changed
structure. It contains 5 words of padding at the end which are not
initialized before being returned to userspace.

Zero the structure in gpio_v2_line_info_change_to_v1() before populating
its contents.

Fixes: aad955842d1c ("gpiolib: cdev: support GPIO_V2_GET_LINEINFO_IOCTL and
GPIO_V2_GET_LINEINFO_WATCH_IOCTL")
Signed-off-by: Gabriel Knezek <gabeknez@xxxxxxxxxxxxxxxxxxx>
---
Changes in v3:
  - Include the Fixes tag referencing the code being fixed and properly
    version the patch.

Changes in v2:
  - Update commit message and subject with suggestions about clarity.
  - Patch series at https://www.spinics.net/lists/linux-gpio/msg62163.html

v1:
  - Initial patch
  - Patch series at https://www.spinics.net/lists/linux-gpio/msg62084.html

 drivers/gpio/gpiolib-cdev.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c
index ee5903aac497..af68532835fe 100644
--- a/drivers/gpio/gpiolib-cdev.c
+++ b/drivers/gpio/gpiolib-cdev.c
@@ -1865,6 +1865,7 @@ static void gpio_v2_line_info_changed_to_v1(
 		struct gpio_v2_line_info_changed *lic_v2,
 		struct gpioline_info_changed *lic_v1)
 {
+	memset(lic_v1, 0, sizeof(*lic_v1));
 	gpio_v2_line_info_to_v1(&lic_v2->info, &lic_v1->info);
 	lic_v1->timestamp = lic_v2->timestamp_ns;
 	lic_v1->event_type = lic_v2->event_type;
-- 
2.25.1