gpio: fix line flag validation in lineevent_create

commit 5ca2f54b597c816df54ff1b28eb99cf7262b955d upstream.

lineevent_create should not allow any of GPIOHANDLE_REQUEST_OUTPUT,
GPIOHANDLE_REQUEST_OPEN_DRAIN or GPIOHANDLE_REQUEST_OPEN_SOURCE to be set.

Fixes: d7c51b47 ("gpio: userspace ABI for reading/writing GPIO lines")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NKent Gibson <warthog618@gmail.com>
Signed-off-by: NBartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/gpio/gpiolib.c

@@ -924,7 +924,9 @@ static int lineevent_create(struct gpio_device *gdev, void __user *ip)
 	}
 
 	/* This is just wrong: we don't look for events on output lines */
-	if (lflags & GPIOHANDLE_REQUEST_OUTPUT) {
+	if ((lflags & GPIOHANDLE_REQUEST_OUTPUT) ||
+	    (lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN) ||
+	    (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE)) {
 		ret = -EINVAL;
 		goto out_free_label;
 	}
@@ -938,10 +940,6 @@ static int lineevent_create(struct gpio_device *gdev, void __user *ip)
 
 	if (lflags & GPIOHANDLE_REQUEST_ACTIVE_LOW)
 		set_bit(FLAG_ACTIVE_LOW, &desc->flags);
-	if (lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN)
-		set_bit(FLAG_OPEN_DRAIN, &desc->flags);
-	if (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE)
-		set_bit(FLAG_OPEN_SOURCE, &desc->flags);
 
 	ret = gpiod_direction_input(desc);
 	if (ret)