[PATCH 4.9 20/62] serial: mctrl_gpio: Check for NULL pointer

Greg Kroah-Hartman
2019-11-04T22:26:27Z

From: Adam Ford <aford173@gmail.com>

[ 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@gmail.com>
Reviewed-by: Yegor Yefremov <yegorslists@googlemail.com>
Link: https://lore.kernel.org/r/20191006163314.23191-1-aford173@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 d2da6aa7f27d0..1bb15edcf1e77 100644
--- a/drivers/tty/serial/serial_mctrl_gpio.c
+++ b/drivers/tty/serial/serial_mctrl_gpio.c
@@ -68,6 +68,9 @@ 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