linux-kernel - [PATCH AUTOSEL 4.4 11/21] serial: mctrl

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Message-Id: <20191018221007.10851-11-sashal@kernel.org>
Date:   Fri, 18 Oct 2019 18:09:57 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Adam Ford <aford173@...il.com>,
        Yegor Yefremov <yegorslists@...glemail.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Sasha Levin <sashal@...nel.org>, linux-serial@...r.kernel.org
Subject: [PATCH AUTOSEL 4.4 11/21] serial: mctrl_gpio: Check for NULL pointer

From: Adam Ford <aford173@...il.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@...il.com>
Reviewed-by: Yegor Yefremov <yegorslists@...glemail.com>
Link: https://lore.kernel.org/r/20191006163314.23191-1-aford173@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Signed-off-by: Sasha Levin <sashal@...nel.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 02147361eaa94..2b5329a3d716a 100644
--- a/drivers/tty/serial/serial_mctrl_gpio.c
+++ b/drivers/tty/serial/serial_mctrl_gpio.c
@@ -67,6 +67,9 @@ 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