Fixup incorrect expansion of the networking mask for dynamic interface

specifications under certain circumstances resulting in potentially
elevated access permissions for IPv6 traffic.  Reported by sthen@;
ok henning benno sthen

3 files changed, 50 insertions, 9 deletions

diff --git a/sbin/pfctl/parse.y b/sbin/pfctl/parse.y
index 5c57fdfd02b..e9ff277c1a0 100644
--- a/sbin/pfctl/parse.y
+++ b/sbin/pfctl/parse.y
@@ -1,4 +1,4 @@
-/*	$OpenBSD: parse.y,v 1.640 2014/10/25 03:18:13 lteo Exp $	*/
+/*	$OpenBSD: parse.y,v 1.641 2014/10/27 21:51:32 mikeb Exp $	*/
 
 /*
  * Copyright (c) 2001 Markus Friedl.  All rights reserved.
@@ -4543,7 +4543,7 @@ expand_rule(struct pf_rule *r, int keeprule, struct node_if *interfaces,
 	char			 tagname[PF_TAG_NAME_SIZE];
 	char			 match_tagname[PF_TAG_NAME_SIZE];
 	u_int8_t		 flags, flagset, keep_state;
-	struct node_host	*srch, *dsth;
+	struct node_host	*srch, *dsth, *osrch, *odsth;
 	struct redirspec	 binat;
 	struct pf_rule		 rb;
 	int			 dir = r->direction;
@@ -4634,6 +4634,18 @@ expand_rule(struct pf_rule *r, int keeprule, struct node_if *interfaces,
 		    r->af, src_host, src_port, dst_host, dst_port,
 		    proto->proto);
 
+		osrch = odsth = NULL;
+		if (src_host->addr.type == PF_ADDR_DYNIFTL) {
+			osrch = src_host;
+			if ((src_host = gen_dynnode(src_host, r->af)) == NULL)
+				err(1, "expand_rule: calloc");
+		}
+		if (dst_host->addr.type == PF_ADDR_DYNIFTL) {
+			odsth = dst_host;
+			if ((dst_host = gen_dynnode(dst_host, r->af)) == NULL)
+				err(1, "expand_rule: calloc");
+		}
+
 		error += check_netmask(src_host, r->af);
 		error += check_netmask(dst_host, r->af);
 
@@ -4784,6 +4796,14 @@ expand_rule(struct pf_rule *r, int keeprule, struct node_if *interfaces,
 			    uid, gid, rcv, icmp_type, anchor_call);
 		}
 
+		if (osrch && src_host->addr.type == PF_ADDR_DYNIFTL) {
+			free(src_host);
+			src_host = osrch;
+		}
+		if (odsth && dst_host->addr.type == PF_ADDR_DYNIFTL) {
+			free(dst_host);
+			dst_host = odsth;
+		}
 	))))))))));
 
 	if (!keeprule) {
diff --git a/sbin/pfctl/pfctl_parser.c b/sbin/pfctl/pfctl_parser.c
index e86b3c66078..ca7780b95bf 100644
--- a/sbin/pfctl/pfctl_parser.c
+++ b/sbin/pfctl/pfctl_parser.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: pfctl_parser.c,v 1.299 2014/10/25 03:18:13 lteo Exp $ */
+/*	$OpenBSD: pfctl_parser.c,v 1.300 2014/10/27 21:51:32 mikeb Exp $ */
 
 /*
  * Copyright (c) 2001 Daniel Hartmeier
@@ -1243,16 +1243,12 @@ int
 check_netmask(struct node_host *h, sa_family_t af)
 {
 	struct node_host	*n = NULL;
-	struct pf_addr	*m;
+	struct pf_addr		*m;
 
 	for (n = h; n != NULL; n = n->next) {
 		if (h->addr.type == PF_ADDR_TABLE)
 			continue;
 		m = &h->addr.v.a.mask;
-		/* fix up netmask for dynaddr */
-		if (af == AF_INET && h->addr.type == PF_ADDR_DYNIFTL &&
-		    unmask(m, AF_INET6) > 32)
-			set_ipmask(n, 32);
 		/* netmasks > 32 bit are invalid on v4 */
 		if (af == AF_INET &&
 		    (m->addr32[1] || m->addr32[2] || m->addr32[3])) {
@@ -1264,6 +1260,30 @@ check_netmask(struct node_host *h, sa_family_t af)
 	return (0);
 }
 
+struct node_host *
+gen_dynnode(struct node_host *h, sa_family_t af)
+{
+	struct node_host	*n;
+	struct pf_addr		*m;
+
+	if (h->addr.type != PF_ADDR_DYNIFTL)
+		return (NULL);
+
+	if ((n = calloc(1, sizeof(*n))) == NULL)
+		return (NULL);
+	bcopy(h, n, sizeof(*n));
+	n->ifname = NULL;
+	n->next = NULL;
+	n->tail = NULL;
+
+	/* fix up netmask */
+	m = &n->addr.v.a.mask;
+	if (af == AF_INET && unmask(m, AF_INET6) > 32)
+		set_ipmask(n, 32);
+
+	return (n);
+}
+
 /* interface lookup routines */
 
 struct node_host	*iftab;
diff --git a/sbin/pfctl/pfctl_parser.h b/sbin/pfctl/pfctl_parser.h
index 3b957b855e5..ec8af3c5923 100644
--- a/sbin/pfctl/pfctl_parser.h
+++ b/sbin/pfctl/pfctl_parser.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: pfctl_parser.h,v 1.103 2014/08/23 00:11:03 pelikan Exp $ */
+/*	$OpenBSD: pfctl_parser.h,v 1.104 2014/10/27 21:51:32 mikeb Exp $ */
 
 /*
  * Copyright (c) 2001 Daniel Hartmeier
@@ -275,6 +275,7 @@ extern const struct pf_timeout pf_timeouts[];
 void			 set_ipmask(struct node_host *, u_int8_t);
 int			 check_netmask(struct node_host *, sa_family_t);
 int			 unmask(struct pf_addr *, sa_family_t);
+struct node_host	*gen_dynnode(struct node_host *, sa_family_t);
 void			 ifa_load(void);
 unsigned int		 ifa_nametoindex(const char *);
 char			*ifa_indextoname(unsigned int, char *);