From b2e8d8da6a5f4cc7955c441d68908992c8de3603 Mon Sep 17 00:00:00 2001
From: Roy Marples <roy@marples.name>
Date: Sat, 24 Nov 2012 20:35:53 +0000
Subject: [PATCH] Avoid sillyness if not a valid IPv6 address

---
 dhcp.c   | 10 ++++++++--
 ipv6rs.c | 32 ++++++++++++++++++++++----------
 2 files changed, 30 insertions(+), 12 deletions(-)

diff --git a/dhcp.c b/dhcp.c
index 3a157350..b27e0a21 100644
--- a/dhcp.c
+++ b/dhcp.c
@@ -1311,7 +1311,9 @@ print_option(char *s, ssize_t len, int type, int dl, const uint8_t *data,
 			while (data < e) {
 				if (l)
 					l++; /* space */
-				l += ipv6_printaddr(NULL, 0, data, ifname);
+				dl = ipv6_printaddr(NULL, 0, data, ifname);
+				if (dl != -1)
+					l += dl;
 				data += 16;
 			}
 			return l + 1;
@@ -1360,7 +1362,11 @@ print_option(char *s, ssize_t len, int type, int dl, const uint8_t *data,
 			l = snprintf(s, len, "%s", inet_ntoa(addr));
 			data += sizeof(addr.s_addr);
 		} else if (type & IPV6) {
-			l = ipv6_printaddr(s, len, data, ifname);
+			dl = ipv6_printaddr(s, len, data, ifname);
+			if (dl != -1)
+				l = dl;
+			else
+				l = 0;	
 			data += 16;
 		} else if (type & BINHEX) {
 			l = snprintf(s, len, "%.2x", data[0]);
diff --git a/ipv6rs.c b/ipv6rs.c
index fc2c3a4c..d04663ff 100644
--- a/ipv6rs.c
+++ b/ipv6rs.c
@@ -382,7 +382,7 @@ add_router(struct ra *router)
 void
 ipv6rs_handledata(_unused void *arg)
 {
-	ssize_t len, l, n, olen;
+	ssize_t len, l, m, n, olen;
 	struct cmsghdr *cm;
 	int hoplimit;
 	struct in6_pktinfo pkt;
@@ -654,22 +654,34 @@ ipv6rs_handledata(_unused void *arg)
 			for (n = ndo->nd_opt_len - 1; n > 1; n -= 2,
 			    op += sizeof(addr.s6_addr))
 			{
-				l += ipv6_printaddr(NULL, 0, op, ifp->name) + 1;
+				m = ipv6_printaddr(NULL, 0, op, ifp->name);
+				if (m != -1)
+					l += m + 1;
 			}
 			op = (uint8_t *)ndo;
 			op += offsetof(struct nd_opt_rdnss,
 			    nd_opt_rdnss_lifetime);
 			op += sizeof(rdnss->nd_opt_rdnss_lifetime);
 			tmp = opt = malloc(l);
-			for (n = ndo->nd_opt_len - 1; n > 1; n -= 2,
-			    op += sizeof(addr.s6_addr))
-			{
-				tmp += ipv6_printaddr(tmp, l, op, ifp->name);
-				*tmp++ = ' ';
-				if (lifetime > 0)
-					has_dns = 1;
+			if (opt) {
+				for (n = ndo->nd_opt_len - 1; n > 1; n -= 2,
+				    op += sizeof(addr.s6_addr))
+				{
+					m = ipv6_printaddr(tmp, l, op,
+					    ifp->name);
+					if (m != -1) {
+						l -= (m + 1);
+						tmp += m;
+						*tmp++ = ' ';
+						if (lifetime > 0)
+							has_dns = 1;
+					}
+				}
+				if (tmp != opt)
+					(*--tmp) = '\0';
+				else
+					*opt = '\0';
 			}
-			(*--tmp) = '\0';
 			break;
 			
 		case ND_OPT_DNSSL: