From: Kent Gibson <warthog618@gmail.com>
Date: Mon, 9 Sep 2019 03:22:18 +0000 (+0000)
Subject: gpio: fix line flag validation in linehandle_create
X-Git-Tag: v4.19.74~34
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=22ed1d47281155d5ecd39e526027c93a096325c7;p=platform%2Fkernel%2Flinux-rpi.git

gpio: fix line flag validation in linehandle_create

commit e95fbc130a162ba9ad956311b95aa0da269eea48 upstream.

linehandle_create should not allow both GPIOHANDLE_REQUEST_INPUT
and GPIOHANDLE_REQUEST_OUTPUT to be set.

Fixes: d7c51b47ac11 ("gpio: userspace ABI for reading/writing GPIO lines")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Kent Gibson <warthog618@gmail.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 5339585..e18d2f6 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -525,6 +525,14 @@ static int linehandle_create(struct gpio_device *gdev, void __user *ip)
 		return -EINVAL;
 
 	/*
+	 * Do not allow both INPUT & OUTPUT flags to be set as they are
+	 * contradictory.
+	 */
+	if ((lflags & GPIOHANDLE_REQUEST_INPUT) &&
+	    (lflags & GPIOHANDLE_REQUEST_OUTPUT))
+		return -EINVAL;
+
+	/*
 	 * Do not allow OPEN_SOURCE & OPEN_DRAIN flags in a single request. If
 	 * the hardware actually supports enabling both at the same time the
 	 * electrical result would be disastrous.