Refactor relay_reply6().

Traverse the nested data structures more efficiently,
more understandably, and with watertight checking of
buffer boundaries.

man/dnsmasq.8

@@ -673,7 +673,7 @@ machine on which dnsmasq is running) for each
 local machine. Local machines are those in /etc/hosts or with DHCP
 leases.
 .TP
-.B \-W, --srv-host=<_service>.<_prot>.[<domain>],[<target>[,<port>[,<priority>[,<weight>]]]]
+.B \-W, --srv-host=<_service>.<_prot>[.<domain>],[<target>[,<port>[,<priority>[,<weight>]]]]
 Return a SRV DNS record. See RFC2782 for details. If not supplied, the
 domain defaults to that given by
 .B --domain.

src/dnsmasq.c

@@ -1777,9 +1777,9 @@ void clear_cache_and_reload(time_t now)
 #ifdef HAVE_DHCP
   if (daemon->dhcp || daemon->doing_dhcp6)
     {
+      reread_dhcp();
       if (option_bool(OPT_ETHERS))
 	dhcp_read_ethers();
-      reread_dhcp();
       dhcp_update_configs(daemon->dhcp_conf);
       lease_update_from_configs(); 
       lease_update_file(now); 

src/forward.c

@@ -763,6 +763,16 @@ static size_t process_reply(struct dns_header *header, time_t now, struct server
   if (!is_sign && !option_bool(OPT_DNSSEC_PROXY))
      header->hb4 &= ~HB4_AD;
 
+  /* Complain loudly if the upstream server is non-recursive. */
+  if (!(header->hb4 & HB4_RA) && rcode == NOERROR &&
+      server && !(server->flags & SERV_WARNED_RECURSIVE))
+    {
+      (void)prettyprint_addr(&server->addr, daemon->namebuff);
+      my_syslog(LOG_WARNING, _("nameserver %s refused to do a recursive query"), daemon->namebuff);
+      if (!option_bool(OPT_LOG))
+	server->flags |= SERV_WARNED_RECURSIVE;
+    }  
+
   header->hb4 |= HB4_RA; /* recursion if available */
 
   if (OPCODE(header) != QUERY)
@@ -778,16 +788,6 @@ static size_t process_reply(struct dns_header *header, time_t now, struct server
       return resize_packet(header, n, pheader, plen);
     }
   
-  /* Complain loudly if the upstream server is non-recursive. */
-  if (!(header->hb4 & HB4_RA) && rcode == NOERROR &&
-      server && !(server->flags & SERV_WARNED_RECURSIVE))
-    {
-      (void)prettyprint_addr(&server->addr, daemon->namebuff);
-      my_syslog(LOG_WARNING, _("nameserver %s refused to do a recursive query"), daemon->namebuff);
-      if (!option_bool(OPT_LOG))
-	server->flags |= SERV_WARNED_RECURSIVE;
-    }  
-
   if (header->hb3 & HB3_TC)
     log_query(F_UPSTREAM, NULL, NULL, "truncated", 0);
   else if (!bogusanswer || (header->hb4 & HB4_CD))

src/option.c

@@ -6262,6 +6262,8 @@ void read_opts(int argc, char **argv, char *compile_opts)
 	    strchr(srv->name, '.') && 
 	    strchr(srv->name, '.') == strrchr(srv->name, '.'))
 	  {
+	    if (strlen(srv->name) + 1 + strlen(daemon->domain_suffix) > MAXDNAME)
+	      die(_("srv-host name %s too long after domain appended"), srv->name, EC_MISC);
 	    strcpy(buff, srv->name);
 	    strcat(buff, ".");
 	    strcat(buff, daemon->domain_suffix);

src/rfc3315.c

@@ -2276,64 +2276,61 @@ int relay_reply6(struct sockaddr_in6 *peer, ssize_t sz, char *arrival_interface)
     {
       void *opt, *opts = inbuff + 34;
       void *end = inbuff + sz;
-      for (opt = opts; opt; opt = opt6_next(opt, end))
-	if (opt6_type(opt) == OPTION6_RELAY_MSG && opt6_len(opt) > 0)
-	  {
-	    int encap_type = *((unsigned char *)opt6_ptr(opt, 0));
-	    put_opt6(opt6_ptr(opt, 0), opt6_len(opt));
-	    memcpy(&peer->sin6_addr, &inbuff[18], IN6ADDRSZ); 
-	    peer->sin6_scope_id = relay->iface_index;
-
-	    if (encap_type == DHCP6RELAYREPL)
-	      {
-		peer->sin6_port = ntohs(DHCPV6_SERVER_PORT);
-		return 1;
-	      }
-
-	    peer->sin6_port = ntohs(DHCPV6_CLIENT_PORT);
-	    
-#ifdef HAVE_SCRIPT
-	    if (daemon->lease_change_command && encap_type == DHCP6REPLY)
-	      {
-		/* decapsulate relayed message */
-		opts = opt6_ptr(opt, 4);
-		end = opt6_ptr(opt, opt6_len(opt));
-
-		for (opt = opts; opt; opt = opt6_next(opt, end))
-		  if (opt6_type(opt) == OPTION6_IA_PD && opt6_len(opt) > 12) 
-		    {
-		      void *ia_opts = opt6_ptr(opt, 12);
-		      void *ia_end = opt6_ptr(opt, opt6_len(opt));
-		      void *ia_opt;
-		      
-		      for (ia_opt = ia_opts; ia_opt; ia_opt = opt6_next(ia_opt, ia_end))
-			/* valid lifetime must not be zero. */
-			if (opt6_type(ia_opt) == OPTION6_IAPREFIX && opt6_len(ia_opt) >= 25 && opt6_uint(ia_opt, 4, 4) != 0)
-			  {
-			    if (daemon->free_snoops ||
-				(daemon->free_snoops = whine_malloc(sizeof(struct snoop_record))))
-			      {
-				struct snoop_record *snoop = daemon->free_snoops;
-				
-				daemon->free_snoops = snoop->next;
-				snoop->client = peer->sin6_addr;
-				snoop->prefix_len = opt6_uint(ia_opt, 8, 1); 
-				memcpy(&snoop->prefix, opt6_ptr(ia_opt, 9), IN6ADDRSZ); 
-				snoop->next = relay->snoop_records;
-				relay->snoop_records = snoop;
-			      }
-			  }
-		    }
-	      }
-#endif		
-	    return 1;
-	  }
       
+      if ((opt = opt6_find(opts, end, OPTION6_RELAY_MSG, 4)))
+	{
+	  int encap_type = opt6_uint(opt, 0, 1);
+	  put_opt6(opt6_ptr(opt, 0), opt6_len(opt));
+	  memcpy(&peer->sin6_addr, &inbuff[18], IN6ADDRSZ); 
+	  peer->sin6_scope_id = relay->iface_index;
+
+	  if (encap_type == DHCP6RELAYREPL)
+	    {
+	      peer->sin6_port = ntohs(DHCPV6_SERVER_PORT);
+	      return 1;
+	    }
+	  
+	  peer->sin6_port = ntohs(DHCPV6_CLIENT_PORT);
+	  
+#ifdef HAVE_SCRIPT
+	  if (daemon->lease_change_command && encap_type == DHCP6REPLY)
+	    {
+	      /* skip over message type and transaction-id. to get to options. */
+	      opts = opt6_ptr(opt, 4);
+	      end = opt6_ptr(opt, opt6_len(opt));
+
+	      if ((opt = opt6_find(opts, end, OPTION6_IA_PD, 12)))
+		{
+		  opts = opt6_ptr(opt, 12);
+		  end = opt6_ptr(opt, opt6_len(opt));
+		  
+		  for (opt = opt6_find(opts, end, OPTION6_IAPREFIX, 25); opt; opt = opt6_find(opt6_next(opt, end), end, OPTION6_IAPREFIX, 25))
+		    /* valid lifetime must not be zero. */
+		    if (opt6_uint(opt, 4, 4) != 0)
+		      {
+			if (daemon->free_snoops ||
+			    (daemon->free_snoops = whine_malloc(sizeof(struct snoop_record))))
+			  {
+			    struct snoop_record *snoop = daemon->free_snoops;
+			    
+			    daemon->free_snoops = snoop->next;
+			    snoop->client = peer->sin6_addr;
+			    snoop->prefix_len = opt6_uint(opt, 8, 1); 
+			    memcpy(&snoop->prefix, opt6_ptr(opt, 9), IN6ADDRSZ); 
+			    snoop->next = relay->snoop_records;
+			    relay->snoop_records = snoop;
+			  }
+		      }
+		}	      
+	    }
+#endif
+	  return 1;
+	}
     }
   
   return 0;
 }
-
+  
 #ifdef HAVE_SCRIPT
 int do_snoop_script_run(void)
 {