[src/trunk]: src/sys/netinet Don't crash if there is no inner IP...

[maxv <maxv%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/f57cedef146a
branches:  trunk
changeset: 319045:f57cedef146a
user:      maxv <maxv%NetBSD.org@localhost>
date:      Mon May 14 17:26:16 2018 +0000
description:
Don't crash if there is no inner IP header.

diffstat:

 sys/netinet/ip_mroute.c |  10 ++++++----
 1 files changed, 6 insertions(+), 4 deletions(-)

diffs (38 lines):

diff -r a406e765f7bd -r f57cedef146a sys/netinet/ip_mroute.c
--- a/sys/netinet/ip_mroute.c   Mon May 14 17:15:54 2018 +0000
+++ b/sys/netinet/ip_mroute.c   Mon May 14 17:26:16 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: ip_mroute.c,v 1.158 2018/05/07 19:34:03 maxv Exp $     */
+/*     $NetBSD: ip_mroute.c,v 1.159 2018/05/14 17:26:16 maxv Exp $     */
 
 /*
  * Copyright (c) 1992, 1993
@@ -93,7 +93,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: ip_mroute.c,v 1.158 2018/05/07 19:34:03 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: ip_mroute.c,v 1.159 2018/05/14 17:26:16 maxv Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_inet.h"
@@ -1828,7 +1828,7 @@
         */
 
        /* Obtain the outer IP header and the vif pointer. */
-       m_copydata((struct mbuf *)m, 0, sizeof(ip), (void *)&ip);
+       m_copydata(m, 0, sizeof(ip), (void *)&ip);
        vifp = (struct vif *)arg;
 
        /*
@@ -1849,7 +1849,9 @@
                return 0;
 
        /* Check that the inner destination is multicast. */
-       m_copydata((struct mbuf *)m, off, sizeof(ip), (void *)&ip);
+       if (off + sizeof(ip) > m->m_pkthdr.len)
+               return 0;
+       m_copydata(m, off, sizeof(ip), (void *)&ip);
        if (!IN_MULTICAST(ip.ip_dst.s_addr))
                return 0;