Btrfs: fix access_ok() check in btrfs_ioctl_send()

commit 700ff4f0 upstream.

The closing parenthesis is in the wrong place.  We want to check
"sizeof(*arg->clone_sources) * arg->clone_sources_count" instead of
"sizeof(*arg->clone_sources * arg->clone_sources_count)".
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Jie Liu <jeff.liu@oracle.com>
Signed-off-by: Chris Mason <clm@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

fs/btrfs/send.c

@@ -4623,8 +4623,8 @@ long btrfs_ioctl_send(struct file *mnt_file, void __user *arg_)
 	}
 
 	if (!access_ok(VERIFY_READ, arg->clone_sources,
-			sizeof(*arg->clone_sources *
-			arg->clone_sources_count))) {
+			sizeof(*arg->clone_sources) *
+			arg->clone_sources_count)) {
 		ret = -EFAULT;
 		goto out;
 	}