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Date:      Fri, 15 Dec 2017 12:37:32 +0000 (UTC)
From:      "Andrey V. Elsukov" <ae@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r326876 - head/sys/netinet6
Message-ID:  <201712151237.vBFCbWnl073250@repo.freebsd.org>
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Author: ae
Date: Fri Dec 15 12:37:32 2017
New Revision: 326876
URL: https://svnweb.freebsd.org/changeset/base/326876

Log:
  Follow the RFC6980 and silently ignore following IPv6 NDP messages
  that had the IPv6 fragmentation header:
   o  Neighbor Solicitation
   o  Neighbor Advertisement
   o  Router Solicitation
   o  Router Advertisement
   o  Redirect
  
  Introduce M_FRAGMENTED mbuf flag, and set it after IPv6 fragment reassembly
  is completed. Then check the presence of this flag in correspondig ND6
  handling routines.
  
  PR:		224247
  MFC after:	2 weeks

Modified:
  head/sys/netinet6/frag6.c
  head/sys/netinet6/icmp6.c
  head/sys/netinet6/in6.h
  head/sys/netinet6/nd6_nbr.c
  head/sys/netinet6/nd6_rtr.c

Modified: head/sys/netinet6/frag6.c
==============================================================================
--- head/sys/netinet6/frag6.c	Fri Dec 15 06:44:11 2017	(r326875)
+++ head/sys/netinet6/frag6.c	Fri Dec 15 12:37:32 2017	(r326876)
@@ -227,6 +227,7 @@ frag6_input(struct mbuf **mp, int *offp, int proto)
 		IP6STAT_INC(ip6s_reassembled);
 		in6_ifstat_inc(dstifp, ifs6_reass_ok);
 		*offp = offset;
+		m->m_flags |= M_FRAGMENTED;
 		return (ip6f->ip6f_nxt);
 	}
 
@@ -827,5 +828,6 @@ ip6_deletefraghdr(struct mbuf *m, int offset, int wait
 		m_cat(m, t);
 	}
 
+	m->m_flags |= M_FRAGMENTED;
 	return (0);
 }

Modified: head/sys/netinet6/icmp6.c
==============================================================================
--- head/sys/netinet6/icmp6.c	Fri Dec 15 06:44:11 2017	(r326875)
+++ head/sys/netinet6/icmp6.c	Fri Dec 15 12:37:32 2017	(r326876)
@@ -2252,6 +2252,10 @@ icmp6_redirect_input(struct mbuf *m, int off)
 	if (!V_icmp6_rediraccept)
 		goto freeit;
 
+	/* RFC 6980: Nodes MUST silently ignore fragments */
+	if(m->m_flags & M_FRAGMENTED)
+		goto freeit;
+
 #ifndef PULLDOWN_TEST
 	IP6_EXTHDR_CHECK(m, off, icmp6len,);
 	nd_rd = (struct nd_redirect *)((caddr_t)ip6 + off);

Modified: head/sys/netinet6/in6.h
==============================================================================
--- head/sys/netinet6/in6.h	Fri Dec 15 06:44:11 2017	(r326875)
+++ head/sys/netinet6/in6.h	Fri Dec 15 12:37:32 2017	(r326876)
@@ -658,6 +658,7 @@ struct ip6_mtuinfo {
 #define	M_LOOP			M_PROTO6
 #define	M_AUTHIPDGM		M_PROTO7
 #define	M_RTALERT_MLD		M_PROTO8
+#define	M_FRAGMENTED		M_PROTO9	/* contained fragment header */
 
 #ifdef _KERNEL
 struct cmsghdr;

Modified: head/sys/netinet6/nd6_nbr.c
==============================================================================
--- head/sys/netinet6/nd6_nbr.c	Fri Dec 15 06:44:11 2017	(r326875)
+++ head/sys/netinet6/nd6_nbr.c	Fri Dec 15 12:37:32 2017	(r326876)
@@ -137,6 +137,10 @@ nd6_ns_input(struct mbuf *m, int off, int icmp6len)
 	struct sockaddr_dl proxydl;
 	char ip6bufs[INET6_ADDRSTRLEN], ip6bufd[INET6_ADDRSTRLEN];
 
+	/* RFC 6980: Nodes MUST silently ignore fragments */
+	if(m->m_flags & M_FRAGMENTED)
+		goto freeit;
+
 	rflag = (V_ip6_forwarding) ? ND_NA_FLAG_ROUTER : 0;
 	if (ND_IFINFO(ifp)->flags & ND6_IFF_ACCEPT_RTADV && V_ip6_norbit_raif)
 		rflag = 0;
@@ -630,6 +634,10 @@ nd6_na_input(struct mbuf *m, int off, int icmp6len)
 	size_t linkhdrsize;
 	int lladdr_off;
 	char ip6bufs[INET6_ADDRSTRLEN], ip6bufd[INET6_ADDRSTRLEN];
+
+	/* RFC 6980: Nodes MUST silently ignore fragments */
+	if(m->m_flags & M_FRAGMENTED)
+		goto freeit;
 
 	if (ip6->ip6_hlim != 255) {
 		nd6log((LOG_ERR,

Modified: head/sys/netinet6/nd6_rtr.c
==============================================================================
--- head/sys/netinet6/nd6_rtr.c	Fri Dec 15 06:44:11 2017	(r326875)
+++ head/sys/netinet6/nd6_rtr.c	Fri Dec 15 12:37:32 2017	(r326876)
@@ -139,6 +139,10 @@ nd6_rs_input(struct mbuf *m, int off, int icmp6len)
 	if (!V_ip6_forwarding || ND_IFINFO(ifp)->flags & ND6_IFF_ACCEPT_RTADV)
 		goto freeit;
 
+	/* RFC 6980: Nodes MUST silently ignore fragments */   
+	if(m->m_flags & M_FRAGMENTED)
+		goto freeit;
+
 	/* Sanity checks */
 	if (ip6->ip6_hlim != 255) {
 		nd6log((LOG_ERR,
@@ -227,6 +231,10 @@ nd6_ra_input(struct mbuf *m, int off, int icmp6len)
 	 * ND6_IFF_ACCEPT_RTADV is on the receiving interface.
 	 */
 	if (!(ndi->flags & ND6_IFF_ACCEPT_RTADV))
+		goto freeit;
+
+	/* RFC 6980: Nodes MUST silently ignore fragments */
+	if(m->m_flags & M_FRAGMENTED)
 		goto freeit;
 
 	if (ip6->ip6_hlim != 255) {

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