pf_cksum_fixup() was called without last argument from normalization,

also fixup checksum when random-id modifies ip_id. This would previously
lead to incorrect checksums for packets modified by scrub random-id.
From Pyun YongHyeon. ok cedric@

3 files changed, 13 insertions, 10 deletions

diff --git a/sys/net/pf.c b/sys/net/pf.c
index 3899a2616b3..e95d1ea41c7 100644
--- a/sys/net/pf.c
+++ b/sys/net/pf.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: pf.c,v 1.447 2004/05/11 07:06:52 dhartmei Exp $ */
+/*	$OpenBSD: pf.c,v 1.448 2004/05/11 07:34:11 dhartmei Exp $ */
 
 /*
  * Copyright (c) 2001 Daniel Hartmeier
@@ -112,8 +112,6 @@ struct pool		 pf_state_pl, pf_altq_pl, pf_pooladdr_pl;
 
 void			 pf_print_host(struct pf_addr *, u_int16_t, u_int8_t);
 
-u_int16_t		 pf_cksum_fixup(u_int16_t, u_int16_t, u_int16_t,
-			    u_int8_t);
 void			 pf_change_ap(struct pf_addr *, u_int16_t *,
 			    u_int16_t *, u_int16_t *, struct pf_addr *,
 			    u_int16_t, u_int8_t, sa_family_t);
diff --git a/sys/net/pf_norm.c b/sys/net/pf_norm.c
index a6528496fb2..18a8b539d02 100644
--- a/sys/net/pf_norm.c
+++ b/sys/net/pf_norm.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: pf_norm.c,v 1.86 2004/05/09 00:16:38 dhartmei Exp $ */
+/*	$OpenBSD: pf_norm.c,v 1.87 2004/05/11 07:34:11 dhartmei Exp $ */
 
 /*
  * Copyright 2001 Niels Provos <provos@citi.umich.edu>
@@ -114,7 +114,6 @@ struct mbuf		*pf_reassemble(struct mbuf **, struct pf_fragment **,
 			    struct pf_frent *, int);
 struct mbuf		*pf_fragcache(struct mbuf **, struct ip*,
 			    struct pf_fragment **, int, int, int *);
-u_int16_t		 pf_cksum_fixup(u_int16_t, u_int16_t, u_int16_t);
 int			 pf_normalize_tcpopt(struct pf_rule *, struct mbuf *,
 			    struct tcphdr *, int);
 
@@ -981,8 +980,12 @@ pf_normalize_ip(struct mbuf **m0, int dir, struct pfi_kif *kif, u_short *reason,
 	if (r->min_ttl && h->ip_ttl < r->min_ttl)
 		h->ip_ttl = r->min_ttl;
 
-	if (r->rule_flag & PFRULE_RANDOMID)
+	if (r->rule_flag & PFRULE_RANDOMID) {
+		u_int16_t ip_id = h->ip_id;
+
 		h->ip_id = ip_randomid();
+		h->ip_sum = pf_cksum_fixup(h->ip_sum, ip_id, h->ip_id, 0);
+	}
 	if ((r->rule_flag & (PFRULE_FRAGCROP|PFRULE_FRAGDROP)) == 0)
 		pd->flags |= PFDESC_IP_REAS;
 
@@ -1282,13 +1285,13 @@ pf_normalize_tcp(int dir, struct pfi_kif *kif, struct mbuf *m, int ipoff,
 		th->th_x2 = 0;
 		nv = *(u_int16_t *)(&th->th_ack + 1);
 
-		th->th_sum = pf_cksum_fixup(th->th_sum, ov, nv);
+		th->th_sum = pf_cksum_fixup(th->th_sum, ov, nv, 0);
 		rewrite = 1;
 	}
 
 	/* Remove urgent pointer, if TH_URG is not set */
 	if (!(flags & TH_URG) && th->th_urp) {
-		th->th_sum = pf_cksum_fixup(th->th_sum, th->th_urp, 0);
+		th->th_sum = pf_cksum_fixup(th->th_sum, th->th_urp, 0, 0);
 		th->th_urp = 0;
 		rewrite = 1;
 	}
@@ -1820,7 +1823,7 @@ pf_normalize_tcpopt(struct pf_rule *r, struct mbuf *m, struct tcphdr *th,
 			mss = (u_int16_t *)(optp + 2);
 			if ((ntohs(*mss)) > r->max_mss) {
 				th->th_sum = pf_cksum_fixup(th->th_sum,
-				    *mss, htons(r->max_mss));
+				    *mss, htons(r->max_mss), 0);
 				*mss = htons(r->max_mss);
 				rewrite = 1;
 			}
diff --git a/sys/net/pfvar.h b/sys/net/pfvar.h
index 8f69e7a0d96..23446fc5676 100644
--- a/sys/net/pfvar.h
+++ b/sys/net/pfvar.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: pfvar.h,v 1.193 2004/05/05 23:16:03 frantzen Exp $ */
+/*	$OpenBSD: pfvar.h,v 1.194 2004/05/11 07:34:11 dhartmei Exp $ */
 
 /*
  * Copyright (c) 2001 Daniel Hartmeier
@@ -1345,6 +1345,8 @@ extern struct pf_ruleset	*pf_find_or_create_ruleset(
 				    char[PF_RULESET_NAME_SIZE]);
 extern void			 pf_remove_if_empty_ruleset(
 				    struct pf_ruleset *);
+extern u_int16_t		 pf_cksum_fixup(u_int16_t, u_int16_t, u_int16_t,
+				    u_int8_t);
 
 extern struct ifnet		*sync_ifp;
 extern struct pf_rule		 pf_default_rule;