svn commit: r329053 - head/sys/netinet6

[Eric van Gyzen]

Author: vangyzen
Date: Fri Feb  9 00:13:05 2018
New Revision: 329053
URL: https://svnweb.freebsd.org/changeset/base/329053

Log:
  Fix ICMPv6 redirects
  
  icmp6_redirect_input() validates that a redirect packet came from the
  current gateway for the respective destination.  To do this, it compares
  the source address, which has an embedded scope zone id, to the next-hop
  address, which does not.  If the address is link-local, which should be
  the case, the comparison fails and the redirect is ignored.
  
  Insert the scope zone id into the next-hop address so the comparison
  is accurate.
  
  Unsurprisingly, this fixes 35 UNH IPv6 conformance test cases.
  
  Submitted by:	Farrell Woods <Farrell_Woods at Dell.com> (initial revision)
  Reviewed by:	ae melifaro dab
  MFC after:	1 week
  Relnotes:	yes
  Sponsored by:	Dell EMC
  Differential Revision:	https://reviews.freebsd.org/D14254

Modified:
  head/sys/netinet6/icmp6.c

Modified: head/sys/netinet6/icmp6.c
==============================================================================
--- head/sys/netinet6/icmp6.c	Thu Feb  8 23:14:24 2018	(r329052)
+++ head/sys/netinet6/icmp6.c	Fri Feb  9 00:13:05 2018	(r329053)
@@ -2305,6 +2305,14 @@ icmp6_redirect_input(struct mbuf *m, int off)
 			goto bad;
 		}
 
+		/*
+		 * Embed scope zone id into next hop address, since
+		 * fib6_lookup_nh_basic() returns address without embedded
+		 * scope zone id.
+		 */
+		if (in6_setscope(&nh6.nh_addr, m->m_pkthdr.rcvif, NULL))
+			goto freeit;
+
 		if (IN6_ARE_ADDR_EQUAL(&src6, &nh6.nh_addr) == 0) {
 			nd6log((LOG_ERR,
 			    "ICMP6 redirect rejected; "