Avoid sillyness if not a valid IPv6 address

diff --git a/ipv6rs.c b/ipv6rs.c
index 0ca5b179f423a5d44d04b44cf0657406d25eea9d..f48d01c7877dff66614510d2b39c6d18b559402e 100644 (file)
--- a/ipv6rs.c
+++ b/ipv6rs.c
@@ -378,7 +378,7 @@ 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;
@@ -632,22 +632,34 @@ 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: