From e3f406b3c1f506c48f09fed9dc1588172a655465 Mon Sep 17 00:00:00 2001
From: Ruslan Ermilov <ru@FreeBSD.org>
Date: Fri, 22 Mar 2002 16:45:54 +0000
Subject: [PATCH] Prevent icmp_reflect() from calling ip_output() with a NULL
 route pointer which will then result in the allocated route's reference count
 never being decremented.  Just flood ping the localhost and watch refcnt of
 the 127.0.0.1 route with netstat(1).

Submitted by:	jayanth

Back out ip_output.c,v 1.143 and ip_mroute.c,v 1.69 that allowed
ip_output() to be called with a NULL route pointer.  The previous
paragraph shows why this was a bad idea in the first place.

MFC after:	0 days
---
 sys/netinet/ip_icmp.c   |  4 ++--
 sys/netinet/ip_mroute.c |  3 ++-
 sys/netinet/ip_output.c | 10 ++++------
 3 files changed, 8 insertions(+), 9 deletions(-)

diff --git a/sys/netinet/ip_icmp.c b/sys/netinet/ip_icmp.c
index c671a0a630ad..7042dd87c4b9 100644
--- a/sys/netinet/ip_icmp.c
+++ b/sys/netinet/ip_icmp.c
@@ -600,6 +600,8 @@ icmp_reflect(m)
 	}
 	t = ip->ip_dst;
 	ip->ip_dst = ip->ip_src;
+	ro = &rt;
+	bzero(ro, sizeof(*ro));
 	/*
 	 * If the incoming packet was addressed directly to us,
 	 * use dst as the src for the reply.  Otherwise (broadcast
@@ -620,8 +622,6 @@ icmp_reflect(m)
 				goto match;
 		}
 	}
-	ro = &rt;
-	bzero(ro, sizeof(*ro));
 	ia = ip_rtaddr(ip->ip_dst, ro);
 	/* We need a route to do anything useful. */
 	if (ia == NULL) {
diff --git a/sys/netinet/ip_mroute.c b/sys/netinet/ip_mroute.c
index 32493080fb60..4847b6d54c58 100644
--- a/sys/netinet/ip_mroute.c
+++ b/sys/netinet/ip_mroute.c
@@ -1867,6 +1867,7 @@ tbf_send_packet(vifp, m)
 {
     struct ip_moptions imo;
     int error;
+    static struct route ro;
     int s = splnet();
 
     if (vifp->v_flags & VIFF_TUNNEL) {
@@ -1885,7 +1886,7 @@ tbf_send_packet(vifp, m)
 	 * should get rejected because they appear to come from
 	 * the loopback interface, thus preventing looping.
 	 */
-	error = ip_output(m, (struct mbuf *)0, NULL,
+	error = ip_output(m, (struct mbuf *)0, &ro,
 			  IP_FORWARDING, &imo);
 
 	if (mrtdebug & DEBUG_XMIT)
diff --git a/sys/netinet/ip_output.c b/sys/netinet/ip_output.c
index d46d9842c9e7..f456456cfbd6 100644
--- a/sys/netinet/ip_output.c
+++ b/sys/netinet/ip_output.c
@@ -123,12 +123,12 @@ ip_output(m0, opt, ro, flags, imo)
 	struct mbuf *m = m0;
 	int hlen = sizeof (struct ip);
 	int len, off, error = 0;
-	struct route iproute;
 	struct sockaddr_in *dst;
 	struct in_ifaddr *ia;
 	int isbroadcast, sw_csum;
 	struct in_addr pkt_dst;
 #ifdef IPSEC
+	struct route iproute;
 	struct socket *so = NULL;
 	struct secpolicy *sp = NULL;
 #endif
@@ -189,6 +189,9 @@ ip_output(m0, opt, ro, flags, imo)
 #ifdef	DIAGNOSTIC
 	if ((m->m_flags & M_PKTHDR) == 0)
 		panic("ip_output no HDR");
+	if (!ro)
+		panic("ip_output no route, proto = %d",
+		      mtod(m, struct ip *)->ip_p);
 #endif
 	if (opt) {
 		m = ip_insertoptions(m, opt, &len);
@@ -214,11 +217,6 @@ ip_output(m0, opt, ro, flags, imo)
 		hlen = IP_VHL_HL(ip->ip_vhl) << 2;
 	}
 
-	/* Route packet. */
-	if (ro == NULL) {
-		ro = &iproute;
-		bzero(ro, sizeof(*ro));
-	}
 	dst = (struct sockaddr_in *)&ro->ro_dst;
 	/*
 	 * If there is a cached route,