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From:   Sasha Levin <sashal@kernel.org>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc:     Gabriel Knezek <gabeknez@linux.microsoft.com>,
        Kent Gibson <warthog618@gmail.com>,
        Bartosz Golaszewski <bgolaszewski@baylibre.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.12 065/110] gpiolib: cdev: zero padding during conversion to gpioline_info_changed
Date:   Mon, 28 Jun 2021 10:17:43 -0400
Message-Id: <20210628141828.31757-66-sashal@kernel.org>
In-Reply-To: <20210628141828.31757-1-sashal@kernel.org>
References: <20210628141828.31757-1-sashal@kernel.org>
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From: Gabriel Knezek <gabeknez@linux.microsoft.com>

[ 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@linux.microsoft.com>
Reviewed-by: Kent Gibson <warthog618@gmail.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 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;
-- 
2.30.2