Commit import of OpenBSD-stable fix:

 Fix by dhartmei@ and mcbride@
 1.433
 Properly m_copyback() modified TCP sequence number after demodulation
 1.432
 Fix icmp checksum when sequence number modlation is being used.
 Also fix a daddr vs saddr cut-n-paste error in ICMP error handling.

 Fixes PR 3724

Obtained from:	OpenBSD
Reviewed by:	dhartmei
Approved by:	rwatson

1 files changed, 11 insertions, 6 deletions

diff --git a/sys/contrib/pf/net/pf.c b/sys/contrib/pf/net/pf.c
index c3d8b99..d492096 100644
--- a/sys/contrib/pf/net/pf.c
+++ b/sys/contrib/pf/net/pf.c
@@ -1,5 +1,5 @@
 /*	$FreeBSD$	*/
-/*	$OpenBSD: pf.c,v 1.389.2.2 2004/03/14 00:13:42 brad Exp $ */
+/*	$OpenBSD: pf.c,v 1.389.2.3 2004/04/10 09:38:19 brad Exp $ */
 
 /*
  * Copyright (c) 2001 Daniel Hartmeier
@@ -4312,6 +4312,7 @@ pf_test_state_icmp(struct pf_state **state, int direction, struct ifnet *ifp,
 			struct pf_tree_node	 key;
 			struct pf_state_peer	*src, *dst;
 			u_int8_t		 dws;
+			int			 copyback = 0;
 
 			/*
 			 * Only the first 8 bytes of the TCP header can be
@@ -4349,9 +4350,11 @@ pf_test_state_icmp(struct pf_state **state, int direction, struct ifnet *ifp,
 
 			/* Demodulate sequence number */
 			seq = ntohl(th.th_seq) - src->seqdiff;
-			if (src->seqdiff)
-				pf_change_a(&th.th_seq, &th.th_sum,
+			if (src->seqdiff) {
+				pf_change_a(&th.th_seq, icmpsum,
 				    htonl(seq), 0);
+				copyback = 1;
+			}
 
 			if (!SEQ_GEQ(src->seqhi, seq) ||
 			    !SEQ_GEQ(seq, src->seqlo - (dst->max_win << dws))) {
@@ -4371,7 +4374,7 @@ pf_test_state_icmp(struct pf_state **state, int direction, struct ifnet *ifp,
 			if (STATE_TRANSLATE(*state)) {
 				if (direction == PF_IN) {
 					pf_change_icmp(pd2.src, &th.th_sport,
-					    saddr, &(*state)->lan.addr,
+					    daddr, &(*state)->lan.addr,
 					    (*state)->lan.port, NULL,
 					    pd2.ip_sum, icmpsum,
 					    pd->ip_sum, 0, pd2.af);
@@ -4382,6 +4385,10 @@ pf_test_state_icmp(struct pf_state **state, int direction, struct ifnet *ifp,
 					    pd2.ip_sum, icmpsum,
 					    pd->ip_sum, 0, pd2.af);
 				}
+				copyback = 1;
+			}
+
+			if (copyback) {
 				switch (pd2.af) {
 #ifdef INET
 				case AF_INET:
@@ -4402,8 +4409,6 @@ pf_test_state_icmp(struct pf_state **state, int direction, struct ifnet *ifp,
 #endif /* INET6 */
 				}
 				m_copyback(m, off2, 8, (caddr_t)&th);
-			} else if (src->seqdiff) {
-				m_copyback(m, off2, 8, (caddr_t)&th);
 			}
 
 			return (PF_PASS);