Index: netbsd32_ioctl.c
===================================================================
RCS file: /cvsroot/src/sys/compat/netbsd32/netbsd32_ioctl.c,v
retrieving revision 1.110
diff -u -u -r1.110 netbsd32_ioctl.c
--- netbsd32_ioctl.c	14 Mar 2020 04:39:15 -0000	1.110
+++ netbsd32_ioctl.c	16 Mar 2020 01:58:54 -0000
@@ -1,4 +1,4 @@
-/*	$NetBSD: netbsd32_ioctl.c,v 1.110 2020/03/14 04:39:15 maxv Exp $	*/
+/*	$NetBSD: netbsd32_ioctl.c,v 1.112 2020/03/16 01:37:51 christos Exp $	*/
 
 /*
  * Copyright (c) 1998, 2001 Matthew R. Green
@@ -31,7 +31,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: netbsd32_ioctl.c,v 1.110 2020/03/14 04:39:15 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: netbsd32_ioctl.c,v 1.112 2020/03/16 01:37:51 christos Exp $");
 
 #if defined(_KERNEL_OPT)
 #include "opt_ntp.h"
@@ -64,6 +64,11 @@
 #include <sys/drvctlio.h>
 #include <sys/compat_stub.h>
 
+#include <sys/vnode.h>
+#include <sys/conf.h>
+#include <miscfs/specfs/specdev.h>
+extern const struct cdevsw clockctl_cdevsw __weak;
+
 #ifdef __sparc__
 #include <dev/sun/fbio.h>
 #include <machine/openpromio.h>
@@ -1041,13 +1046,30 @@
 
 #ifdef NTP
 static int
-netbsd32_do_clockctl_ntp_adjtime(struct clockctl_ntp_adjtime *args)
+netbsd32_do_clockctl_ntp_adjtime(struct file *fp,
+    struct clockctl_ntp_adjtime *args)
 {
+	struct vnode *vp;
+	struct specnode *sn;
+	const struct cdevsw *cdev;
 
 	struct netbsd32_timex ntv32;
 	struct timex ntv;
 	int error;
 
+	/* Verify that the file descriptor is is to the clockctl device */
+	if (fp->f_type != DTYPE_VNODE)
+		return EINVAL;
+
+	vp = fp->f_vnode;
+	if (vp->v_type != VCHR)
+		return EINVAL;
+
+	sn = vp->v_specnode;
+	cdev = cdevsw_lookup(sn->sn_rdev);
+	if (cdev == NULL || cdev != &clockctl_cdevsw)
+		return EINVAL;
+
 	if (vec_ntp_adjtime1 == NULL)
 		return EINVAL;
 
@@ -1469,7 +1491,7 @@
 				(const struct netbsd32_clockctl_ntp_adjtime *)data32,
 				(struct clockctl_ntp_adjtime *)data,
 				CLOCKCTL_NTP_ADJTIME);
-			error = netbsd32_do_clockctl_ntp_adjtime(
+			error = netbsd32_do_clockctl_ntp_adjtime(fp,
 				(struct clockctl_ntp_adjtime *)data);
 			netbsd32_from_clockctl_ntp_adjtime(
 				(const struct clockctl_ntp_adjtime *)data,