Merge tag '20160610_uvc_compat_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/luto/linux

Pull uvc compat XU ioctl fixes from Andy Lutomirski:
 "uvc's compat XU ioctls go through tons of potentially buggy
  indirection.  The first patch removes the indirection.  The second one
  cleans up the code.

  Compile-tested only.  I have the hardware, but I have absolutely no
  idea what XU does, how to use it, what software to recompile as
  32-bit, or what to test in that software"

* tag '20160610_uvc_compat_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/luto/linux:
  uvc_v4l2: Simplify compat ioctl implementation
  uvc: Forward compat ioctls to their handlers directly

drivers/media/usb/uvc/uvc_v4l2.c

@@ -1274,8 +1274,6 @@ struct uvc_xu_control_mapping32 {
 static int uvc_v4l2_get_xu_mapping(struct uvc_xu_control_mapping *kp,
 			const struct uvc_xu_control_mapping32 __user *up)
 {
-	struct uvc_menu_info __user *umenus;
-	struct uvc_menu_info __user *kmenus;
 	compat_caddr_t p;
 
 	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
@@ -1292,17 +1290,7 @@ static int uvc_v4l2_get_xu_mapping(struct uvc_xu_control_mapping *kp,
 
 	if (__get_user(p, &up->menu_info))
 		return -EFAULT;
-	umenus = compat_ptr(p);
-	if (!access_ok(VERIFY_READ, umenus, kp->menu_count * sizeof(*umenus)))
-		return -EFAULT;
-
-	kmenus = compat_alloc_user_space(kp->menu_count * sizeof(*kmenus));
-	if (kmenus == NULL)
-		return -EFAULT;
-	kp->menu_info = kmenus;
-
-	if (copy_in_user(kmenus, umenus, kp->menu_count * sizeof(*umenus)))
-		return -EFAULT;
+	kp->menu_info = compat_ptr(p);
 
 	return 0;
 }
@@ -1310,10 +1298,6 @@ static int uvc_v4l2_get_xu_mapping(struct uvc_xu_control_mapping *kp,
 static int uvc_v4l2_put_xu_mapping(const struct uvc_xu_control_mapping *kp,
 			struct uvc_xu_control_mapping32 __user *up)
 {
-	struct uvc_menu_info __user *umenus;
-	struct uvc_menu_info __user *kmenus = kp->menu_info;
-	compat_caddr_t p;
-
 	if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
 	    __copy_to_user(up, kp, offsetof(typeof(*up), menu_info)) ||
 	    __put_user(kp->menu_count, &up->menu_count))
@@ -1322,16 +1306,6 @@ static int uvc_v4l2_put_xu_mapping(const struct uvc_xu_control_mapping *kp,
 	if (__clear_user(up->reserved, sizeof(up->reserved)))
 		return -EFAULT;
 
-	if (kp->menu_count == 0)
-		return 0;
-
-	if (get_user(p, &up->menu_info))
-		return -EFAULT;
-	umenus = compat_ptr(p);
-
-	if (copy_in_user(umenus, kmenus, kp->menu_count * sizeof(*umenus)))
-		return -EFAULT;
-
 	return 0;
 }
 
@@ -1346,8 +1320,6 @@ struct uvc_xu_control_query32 {
 static int uvc_v4l2_get_xu_query(struct uvc_xu_control_query *kp,
 			const struct uvc_xu_control_query32 __user *up)
 {
-	u8 __user *udata;
-	u8 __user *kdata;
 	compat_caddr_t p;
 
 	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
@@ -1361,17 +1333,7 @@ static int uvc_v4l2_get_xu_query(struct uvc_xu_control_query *kp,
 
 	if (__get_user(p, &up->data))
 		return -EFAULT;
-	udata = compat_ptr(p);
-	if (!access_ok(VERIFY_READ, udata, kp->size))
-		return -EFAULT;
-
-	kdata = compat_alloc_user_space(kp->size);
-	if (kdata == NULL)
-		return -EFAULT;
-	kp->data = kdata;
-
-	if (copy_in_user(kdata, udata, kp->size))
-		return -EFAULT;
+	kp->data = compat_ptr(p);
 
 	return 0;
 }
@@ -1379,26 +1341,10 @@ static int uvc_v4l2_get_xu_query(struct uvc_xu_control_query *kp,
 static int uvc_v4l2_put_xu_query(const struct uvc_xu_control_query *kp,
 			struct uvc_xu_control_query32 __user *up)
 {
-	u8 __user *udata;
-	u8 __user *kdata = kp->data;
-	compat_caddr_t p;
-
 	if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
 	    __copy_to_user(up, kp, offsetof(typeof(*up), data)))
 		return -EFAULT;
 
-	if (kp->size == 0)
-		return 0;
-
-	if (get_user(p, &up->data))
-		return -EFAULT;
-	udata = compat_ptr(p);
-	if (!access_ok(VERIFY_READ, udata, kp->size))
-		return -EFAULT;
-
-	if (copy_in_user(udata, kdata, kp->size))
-		return -EFAULT;
-
 	return 0;
 }
 
@@ -1408,47 +1354,44 @@ static int uvc_v4l2_put_xu_query(const struct uvc_xu_control_query *kp,
 static long uvc_v4l2_compat_ioctl32(struct file *file,
 		     unsigned int cmd, unsigned long arg)
 {
+	struct uvc_fh *handle = file->private_data;
 	union {
 		struct uvc_xu_control_mapping xmap;
 		struct uvc_xu_control_query xqry;
 	} karg;
 	void __user *up = compat_ptr(arg);
-	mm_segment_t old_fs;
 	long ret;
 
 	switch (cmd) {
 	case UVCIOC_CTRL_MAP32:
-		cmd = UVCIOC_CTRL_MAP;
 		ret = uvc_v4l2_get_xu_mapping(&karg.xmap, up);
+		if (ret)
+			return ret;
+		ret = uvc_ioctl_ctrl_map(handle->chain, &karg.xmap);
+		if (ret)
+			return ret;
+		ret = uvc_v4l2_put_xu_mapping(&karg.xmap, up);
+		if (ret)
+			return ret;
+
 		break;
 
 	case UVCIOC_CTRL_QUERY32:
-		cmd = UVCIOC_CTRL_QUERY;
 		ret = uvc_v4l2_get_xu_query(&karg.xqry, up);
+		if (ret)
+			return ret;
+		ret = uvc_xu_ctrl_query(handle->chain, &karg.xqry);
+		if (ret)
+			return ret;
+		ret = uvc_v4l2_put_xu_query(&karg.xqry, up);
+		if (ret)
+			return ret;
 		break;
 
 	default:
 		return -ENOIOCTLCMD;
 	}
 
-	old_fs = get_fs();
-	set_fs(KERNEL_DS);
-	ret = video_ioctl2(file, cmd, (unsigned long)&karg);
-	set_fs(old_fs);
-
-	if (ret < 0)
-		return ret;
-
-	switch (cmd) {
-	case UVCIOC_CTRL_MAP:
-		ret = uvc_v4l2_put_xu_mapping(&karg.xmap, up);
-		break;
-
-	case UVCIOC_CTRL_QUERY:
-		ret = uvc_v4l2_put_xu_query(&karg.xqry, up);
-		break;
-	}
-
 	return ret;
 }
 #endif