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-Url: https://git.stricted.de/?a=commitdiff_plain;h=71bbfc9042e9226cf10f129a2b28a89ba3c00c80;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.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 3b0d77b2fdc5..0ca8f3ec82b1 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -426,12 +426,23 @@ static int linehandle_create(struct gpio_device *gdev, void __user *ip)
 	struct linehandle_state *lh;
 	struct file *file;
 	int fd, i, count = 0, ret;
+	u32 lflags;
 
 	if (copy_from_user(&handlereq, ip, sizeof(handlereq)))
 		return -EFAULT;
 	if ((handlereq.lines == 0) || (handlereq.lines > GPIOHANDLES_MAX))
 		return -EINVAL;
 
+	lflags = handlereq.flags;
+
+	/*
+	 * 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;
+
 	lh = kzalloc(sizeof(*lh), GFP_KERNEL);
 	if (!lh)
 		return -ENOMEM;
@@ -452,7 +463,6 @@ static int linehandle_create(struct gpio_device *gdev, void __user *ip)
 	/* Request each GPIO */
 	for (i = 0; i < handlereq.lines; i++) {
 		u32 offset = handlereq.lineoffsets[i];
-		u32 lflags = handlereq.flags;
 		struct gpio_desc *desc;
 
 		if (offset >= gdev->ngpio) {