We should ignore DHCP messages without a ServerID, #166.

diff --git a/dhcpcd.c b/dhcpcd.c
index f32e0459baf8910f040c0678b1fa87a5d41e7a14..82831873d3170a150509652d1d4d172b6c199951 100644 (file)
--- a/dhcpcd.c
+++ b/dhcpcd.c
@@ -456,6 +456,12 @@ handle_dhcp(struct interface *iface, struct dhcp_message **dhcpp)
        /* We may have found a BOOTP server */
        if (get_option_uint8(&type, dhcp, DHO_MESSAGETYPE) == -1) 
                type = 0;
+       else if (get_option_addr(&addr.s_addr, dhcp, DHO_SERVERID) == -1) {
+               /* We should ignore invalid NAK messages without a ServerID */
+               syslog(LOG_WARNING, "%s: ignoring DHCP message; no Server ID",
+                   iface->name);
+               return;
+       }
 
        /* We should restart on a NAK */
        if (type == DHCP_NAK) {
@@ -494,9 +500,8 @@ handle_dhcp(struct interface *iface, struct dhcp_message **dhcpp)
                lease->frominfo = 0;
                lease->addr.s_addr = dhcp->yiaddr;
                lease->server.s_addr = 0;
-               if (type)
-                       get_option_addr(&lease->server.s_addr, dhcp,
-                           DHO_SERVERID);
+               if (type != 0)
+                       lease->server.s_addr = addr.s_addr;
                log_dhcp(LOG_INFO, "offered", iface, dhcp);
                free(state->offer);
                state->offer = dhcp;