From f074e7d461c6e3fdf7124987027f28d88c3b8cec Mon Sep 17 00:00:00 2001
From: mpi <mpi@openbsd.org>
Date: Fri, 10 Apr 2015 08:48:24 +0000
Subject: [PATCH] Run detach hook and similar before cleaning up any other
 resource when an interface is destroyed/removed.  This way we can ensure
 pseudo-driver changes done after attaching an interface are undone before
 detaching it.

Note: it is safe to call if_deactivate() multiple times as the interface
should not have any attached pseudo-interface after the first call.

ok deraadt@, dlg@
---
 sys/net/if.c           | 54 ++++++++++++++++++++++++++----------------
 sys/net/if.h           |  3 ++-
 sys/net/if_ethersubr.c |  5 +++-
 3 files changed, 40 insertions(+), 22 deletions(-)

diff --git a/sys/net/if.c b/sys/net/if.c
index c697bfe18d6..a7c317cde30 100644
--- a/sys/net/if.c
+++ b/sys/net/if.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if.c,v 1.327 2015/04/07 10:46:20 mpi Exp $	*/
+/*	$OpenBSD: if.c,v 1.328 2015/04/10 08:48:24 mpi Exp $	*/
 /*	$NetBSD: if.c,v 1.35 1996/05/07 05:26:04 thorpej Exp $	*/
 
 /*
@@ -521,22 +521,12 @@ nettxintr(void)
 	splx(s);
 }
 
-/*
- * Detach an interface from everything in the kernel.  Also deallocate
- * private resources.
- */
 void
-if_detach(struct ifnet *ifp)
+if_deactivate(struct ifnet *ifp)
 {
-	struct ifaddr *ifa;
-	struct ifg_list *ifg;
-	int s = splnet();
-	struct domain *dp;
+	int s;
 
-	ifp->if_flags &= ~IFF_OACTIVE;
-	ifp->if_start = if_detached_start;
-	ifp->if_ioctl = if_detached_ioctl;
-	ifp->if_watchdog = NULL;
+	s = splnet();
 
 	/*
 	 * Call detach hooks from head to tail.  To make sure detach
@@ -545,12 +535,6 @@ if_detach(struct ifnet *ifp)
 	 */
 	dohooks(ifp->if_detachhooks, HOOK_REMOVE | HOOK_FREE);
 
-	/* Remove the watchdog timeout */
-	timeout_del(ifp->if_slowtimo);
-
-	/* Remove the link state task */
-	task_del(systq, ifp->if_linkstatetask);
-
 #if NBRIDGE > 0
 	/* Remove the interface from any bridge it is part of.  */
 	if (ifp->if_bridgeport)
@@ -563,6 +547,36 @@ if_detach(struct ifnet *ifp)
 		carp_ifdetach(ifp);
 #endif
 
+	splx(s);
+}
+
+/*
+ * Detach an interface from everything in the kernel.  Also deallocate
+ * private resources.
+ */
+void
+if_detach(struct ifnet *ifp)
+{
+	struct ifaddr *ifa;
+	struct ifg_list *ifg;
+	struct domain *dp;
+	int s;
+
+	/* Undo pseudo-driver changes. */
+	if_deactivate(ifp);
+
+	s = splnet();
+	ifp->if_flags &= ~IFF_OACTIVE;
+	ifp->if_start = if_detached_start;
+	ifp->if_ioctl = if_detached_ioctl;
+	ifp->if_watchdog = NULL;
+
+	/* Remove the watchdog timeout */
+	timeout_del(ifp->if_slowtimo);
+
+	/* Remove the link state task */
+	task_del(systq, ifp->if_linkstatetask);
+
 #if NBPFILTER > 0
 	bpfdetach(ifp);
 #endif
diff --git a/sys/net/if.h b/sys/net/if.h
index 70e574b2089..20d69d6c4c8 100644
--- a/sys/net/if.h
+++ b/sys/net/if.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if.h,v 1.161 2015/03/18 12:23:15 dlg Exp $	*/
+/*	$OpenBSD: if.h,v 1.162 2015/04/10 08:48:24 mpi Exp $	*/
 /*	$NetBSD: if.h,v 1.23 1996/05/07 02:40:27 thorpej Exp $	*/
 
 /*
@@ -446,6 +446,7 @@ void	if_attach(struct ifnet *);
 void	if_attachdomain(void);
 void	if_attachtail(struct ifnet *);
 void	if_attachhead(struct ifnet *);
+void	if_deactivate(struct ifnet *);
 void	if_detach(struct ifnet *);
 void	if_down(struct ifnet *);
 void	if_downall(void);
diff --git a/sys/net/if_ethersubr.c b/sys/net/if_ethersubr.c
index 292b6871401..2bd2e75acae 100644
--- a/sys/net/if_ethersubr.c
+++ b/sys/net/if_ethersubr.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_ethersubr.c,v 1.191 2015/04/07 10:46:20 mpi Exp $	*/
+/*	$OpenBSD: if_ethersubr.c,v 1.192 2015/04/10 08:48:24 mpi Exp $	*/
 /*	$NetBSD: if_ethersubr.c,v 1.19 1996/05/07 02:40:30 thorpej Exp $	*/
 
 /*
@@ -802,6 +802,9 @@ ether_ifdetach(struct ifnet *ifp)
 	struct ifih *ether_ifih;
 	struct ether_multi *enm;
 
+	/* Undo pseudo-driver changes. */
+	if_deactivate(ifp);
+
 	ether_ifih = SLIST_FIRST(&ifp->if_inputs);
 	SLIST_REMOVE_HEAD(&ifp->if_inputs, ifih_next);
 
-- 
2.20.1