[PATCH 5.12 065/110] gpiolib: cdev: zero padding during conversion to gpioline_info_changed

From: Sasha Levin
Date: Mon Jun 28 2021 - 10:23:50 EST

From: Gabriel Knezek <gabeknez@xxxxxxxxxxxxxxxxxxx>

[ Upstream commit cb8f63b8cbf39845244f3ccae43bb7e63bd70543 ]

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>
Reviewed-by: Kent Gibson <warthog618@xxxxxxxxx>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
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 1631727bf0da..c7b5446d01fd 100644
--- a/drivers/gpio/gpiolib-cdev.c
+++ b/drivers/gpio/gpiolib-cdev.c
@@ -1880,6 +1880,7 @@ 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;