From 181a4a2d5a0a7b43cab08a70710d727e7764ccdd Mon Sep 17 00:00:00 2001
From: Hans Verkuil <hans.verkuil@cisco.com>
Date: Tue, 30 Jan 2018 03:50:01 -0500
Subject: [PATCH] media: v4l2-ioctl.c: don't copy back the result for -ENOTTY
Git-commit: 181a4a2d5a0a7b43cab08a70710d727e7764ccdd
Patch-mainline: v4.16-rc1
References: CVE-2017-13166,bsc#1072865

If the ioctl returned -ENOTTY, then don't bother copying
back the result as there is no point.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: <stable@vger.kernel.org>      # for v4.15 and up
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/media/v4l2-core/v4l2-ioctl.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/drivers/media/v4l2-core/v4l2-ioctl.c
+++ b/drivers/media/v4l2-core/v4l2-ioctl.c
@@ -2838,8 +2838,11 @@ video_usercopy(struct file *file, unsign
 
 	/* Handles IOCTL */
 	err = func(file, cmd, parg);
-	if (err == -ENOIOCTLCMD)
+	if (err == -ENOTTY || err == -ENOIOCTLCMD) {
 		err = -ENOTTY;
+		goto out;
+	}
+
 	if (err == 0) {
 		if (cmd == VIDIOC_DQBUF)
 			trace_v4l2_dqbuf(video_devdata(file)->minor, parg);