From 850d36efb2ae248d4c7415508dac8f62dcc93a7b Mon Sep 17 00:00:00 2001
From: David Gwynne <dlg@cvs.openbsd.org>
Date: Mon, 12 Nov 2018 06:35:38 +0000
Subject: limit the number of interface units to the number of device minors

this prevents creation of tap and tun devices that you cannot open
from userland because of the limit on the number of dev_t minor
numbers.

the lack of limit was pointed out by Greg Steuck
ok deraadt@ guenther@
---
 sys/net/if_tun.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

(limited to 'sys')

diff --git a/sys/net/if_tun.c b/sys/net/if_tun.c
index 33f97655d53..e08bb61a52d 100644
--- a/sys/net/if_tun.c
+++ b/sys/net/if_tun.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_tun.c,v 1.181 2018/02/24 07:20:04 dlg Exp $	*/
+/*	$OpenBSD: if_tun.c,v 1.182 2018/11/12 06:35:37 dlg Exp $	*/
 /*	$NetBSD: if_tun.c,v 1.24 1996/05/07 02:40:48 thorpej Exp $	*/
 
 /*
@@ -193,6 +193,9 @@ tun_create(struct if_clone *ifc, int unit, int flags)
 	struct tun_softc	*tp;
 	struct ifnet		*ifp;
 
+	if (unit > minor(~0U))
+		return (ENXIO);
+
 	tp = malloc(sizeof(*tp), M_DEVBUF, M_WAITOK|M_ZERO);
 	tp->tun_unit = unit;
 	tp->tun_flags = TUN_INITED|TUN_STAYUP;
-- 
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