+ /*
+ * if reverse lookup result looks like a numeric hostname,
+ * someone is trying to trick us by PTR record like following:
+ * 1.1.1.10.in-addr.arpa. IN PTR 2.3.4.5
+ */
+ memset(&hints, 0, sizeof(hints));
+ hints.ai_socktype = SOCK_DGRAM; /*dummy*/
+ hints.ai_flags = AI_NUMERICHOST;
+ if (getaddrinfo(name, NULL, &hints, &ai) == 0) {
+ logit("Nasty PTR record \"%s\" is set up for %s, ignoring",
+ name, ntop);
+ freeaddrinfo(ai);
+ return xstrdup(ntop);
+ }
+
+ /*
+ * Convert it to all lowercase (which is expected by the rest
+ * of this software).
+ */
+ for (i = 0; name[i]; i++)
+ if (isupper(name[i]))
+ name[i] = (char)tolower(name[i]);
+ /*
+ * Map it back to an IP address and check that the given
+ * address actually is an address of this host. This is
+ * necessary because anyone with access to a name server can
+ * define arbitrary names for an IP address. Mapping from
+ * name to IP address can be trusted better (but can still be
+ * fooled if the intruder has access to the name server of
+ * the domain).
+ */
+ memset(&hints, 0, sizeof(hints));
+ hints.ai_family = from.ss_family;
+ hints.ai_socktype = SOCK_STREAM;
+ if (getaddrinfo(name, NULL, &hints, &aitop) != 0) {
+ logit("reverse mapping checking getaddrinfo for %.700s "
+ "[%s] failed - POSSIBLE BREAK-IN ATTEMPT!", name, ntop);
+ return xstrdup(ntop);
+ }
+ /* Look for the address from the list of addresses. */
+ for (ai = aitop; ai; ai = ai->ai_next) {
+ if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop2,
+ sizeof(ntop2), NULL, 0, NI_NUMERICHOST) == 0 &&
+ (strcmp(ntop, ntop2) == 0))
+ break;
+ }
+ freeaddrinfo(aitop);
+ /* If we reached the end of the list, the address was not there. */
+ if (!ai) {
+ /* Address not found for the host name. */
+ logit("Address %.100s maps to %.600s, but this does not "
+ "map back to the address - POSSIBLE BREAK-IN ATTEMPT!",
+ ntop, name);
+ return xstrdup(ntop);
+ }
+ return xstrdup(name);
+}
+
+/*
+ * If IP options are supported, make sure there are none (log and
+ * disconnect them if any are found). Basically we are worried about
+ * source routing; it can be used to pretend you are somebody
+ * (ip-address) you are not. That itself may be "almost acceptable"
+ * under certain circumstances, but rhosts autentication is useless
+ * if source routing is accepted. Notice also that if we just dropped
+ * source routing here, the other side could use IP spoofing to do
+ * rest of the interaction and could still bypass security. So we
+ * exit here if we detect any IP options.
+ */
+/* IPv4 only */
+static void
+check_ip_options(int sock, char *ipaddr)
+{
+#ifdef IP_OPTIONS
+ u_char options[200];
+ char text[sizeof(options) * 3 + 1];
+ socklen_t option_size;
+ u_int i;
+ int ipproto;
+ struct protoent *ip;
+
+ if ((ip = getprotobyname("ip")) != NULL)
+ ipproto = ip->p_proto;
+ else
+ ipproto = IPPROTO_IP;
+ option_size = sizeof(options);
+ if (getsockopt(sock, ipproto, IP_OPTIONS, options,
+ &option_size) >= 0 && option_size != 0) {
+ text[0] = '\0';
+ for (i = 0; i < option_size; i++)
+ snprintf(text + i*3, sizeof(text) - i*3,
+ " %2.2x", options[i]);
+ fatal("Connection from %.100s with IP options:%.800s",
+ ipaddr, text);
+ }
+#endif /* IP_OPTIONS */
+}
+
+void
+ipv64_normalise_mapped(struct sockaddr_storage *addr, socklen_t *len)
+{
+ struct sockaddr_in6 *a6 = (struct sockaddr_in6 *)addr;
+ struct sockaddr_in *a4 = (struct sockaddr_in *)addr;
+ struct in_addr inaddr;
+ u_int16_t port;
+
+ if (addr->ss_family != AF_INET6 ||
+ !IN6_IS_ADDR_V4MAPPED(&a6->sin6_addr))
+ return;
+
+ debug3("Normalising mapped IPv4 in IPv6 address");
+
+ memcpy(&inaddr, ((char *)&a6->sin6_addr) + 12, sizeof(inaddr));
+ port = a6->sin6_port;
+
+ memset(addr, 0, sizeof(*a4));