[PATCH AUTOSEL 4.19 074/100] serial: mctrl_gpio: Check for NULL pointer

From: Sasha Levin
Date: Fri Oct 18 2019 - 18:07:17 EST


From: Adam Ford <aford173@xxxxxxxxx>

[ Upstream commit 37e3ab00e4734acc15d96b2926aab55c894f4d9c ]

When using mctrl_gpio_to_gpiod, it dereferences gpios into a single
requested GPIO. This dereferencing can break if gpios is NULL,
so this patch adds a NULL check before dereferencing it. If
gpios is NULL, this function will also return NULL.

Signed-off-by: Adam Ford <aford173@xxxxxxxxx>
Reviewed-by: Yegor Yefremov <yegorslists@xxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20191006163314.23191-1-aford173@xxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/tty/serial/serial_mctrl_gpio.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/drivers/tty/serial/serial_mctrl_gpio.c b/drivers/tty/serial/serial_mctrl_gpio.c
index 07f318603e740..af0412a784d27 100644
--- a/drivers/tty/serial/serial_mctrl_gpio.c
+++ b/drivers/tty/serial/serial_mctrl_gpio.c
@@ -60,6 +60,9 @@ EXPORT_SYMBOL_GPL(mctrl_gpio_set);
struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios,
enum mctrl_gpio_idx gidx)
{
+ if (gpios == NULL)
+ return NULL;
+
return gpios->gpio[gidx];
}
EXPORT_SYMBOL_GPL(mctrl_gpio_to_gpiod);
--
2.20.1