From a751be5b142ef6bcbbb96d9899516f4d9c8d0ef4 Mon Sep 17 00:00:00 2001
From: Hans Verkuil <hans.verkuil@cisco.com>
Date: Wed, 24 Jan 2018 06:03:08 -0500
Subject: [PATCH] media: v4l2-compat-ioctl32.c: copy clip list in put_v4l2_window32
Git-commit: a751be5b142ef6bcbbb96d9899516f4d9c8d0ef4
Patch-mainline: v4.16-rc1
References: CVE-2017-13166,bsc#1072865

put_v4l2_window32() didn't copy back the clip list to userspace.
Drivers can update the clip rectangles, so this should be done.

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-compat-ioctl32.c |   59 +++++++++++++++++---------
 1 file changed, 40 insertions(+), 19 deletions(-)

--- a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
+++ b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
@@ -49,6 +49,11 @@ struct v4l2_window32 {
 
 static int get_v4l2_window32(struct v4l2_window *kp, struct v4l2_window32 __user *up)
 {
+	struct v4l2_clip32 __user *uclips;
+	struct v4l2_clip __user *kclips;
+	compat_caddr_t p;
+	u32 n;
+
 	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
 	    copy_from_user(&kp->w, &up->w, sizeof(up->w)) ||
 	    get_user(kp->field, &up->field) ||
@@ -57,37 +62,53 @@ static int get_v4l2_window32(struct v4l2
 		return -EFAULT;
 	if (kp->clipcount > 2048)
 		return -EINVAL;
-	if (kp->clipcount) {
-		struct v4l2_clip32 __user *uclips;
-		struct v4l2_clip __user *kclips;
-		int n = kp->clipcount;
-		compat_caddr_t p;
+	if (!kp->clipcount) {
+		kp->clips = NULL;
+		return 0;
+	}
 
-		if (get_user(p, &up->clips))
+	n = kp->clipcount;
+	if (get_user(p, &up->clips))
+		return -EFAULT;
+	uclips = compat_ptr(p);
+	kclips = compat_alloc_user_space(n * sizeof(*kclips));
+	kp->clips = kclips;
+	while (n--) {
+		if (copy_in_user(&kclips->c, &uclips->c, sizeof(uclips->c)))
 			return -EFAULT;
-		uclips = compat_ptr(p);
-		kclips = compat_alloc_user_space(n * sizeof(*kclips));
-		kp->clips = kclips;
-		while (--n >= 0) {
-			if (copy_in_user(&kclips->c, &uclips->c, sizeof(uclips->c)))
-				return -EFAULT;
-			if (put_user(n ? kclips + 1 : NULL, &kclips->next))
-				return -EFAULT;
-			uclips += 1;
-			kclips += 1;
-		}
-	} else
-		kp->clips = NULL;
+		if (put_user(n ? kclips + 1 : NULL, &kclips->next))
+			return -EFAULT;
+		uclips++;
+		kclips++;
+	}
 	return 0;
 }
 
 static int put_v4l2_window32(struct v4l2_window *kp, struct v4l2_window32 __user *up)
 {
+	struct v4l2_clip __user *kclips = kp->clips;
+	struct v4l2_clip32 __user *uclips;
+	u32 n = kp->clipcount;
+	compat_caddr_t p;
+
 	if (copy_to_user(&up->w, &kp->w, sizeof(kp->w)) ||
 	    put_user(kp->field, &up->field) ||
 	    put_user(kp->chromakey, &up->chromakey) ||
 	    put_user(kp->clipcount, &up->clipcount))
 		return -EFAULT;
+
+	if (!kp->clipcount)
+		return 0;
+
+	if (get_user(p, &up->clips))
+		return -EFAULT;
+	uclips = compat_ptr(p);
+	while (n--) {
+		if (copy_in_user(&uclips->c, &kclips->c, sizeof(uclips->c)))
+			return -EFAULT;
+		uclips++;
+		kclips++;
+	}
 	return 0;
 }