fix null pointer dereference for INFORM messages

diff --git a/src/dhcpv4.c b/src/dhcpv4.c
index f0780876ebbe47c71a71a6d460fa9084508c2e44..7ac7af9e73b7d5197bb32991d7217d850753061f 100644 (file)
--- a/src/dhcpv4.c
+++ b/src/dhcpv4.c
@@ -849,7 +849,7 @@ void dhcpv4_handle_msg(void *addr, void *data, size_t len,
                dhcpv4_put(&reply, &cookie, DHCPV4_OPT_DNSSERVER,
                                4 * iface->dhcpv4_dns_cnt, iface->dhcpv4_dns);
 
-       if (a->reqopts && iface->dhcpv4_ntp_cnt != 0) {
+       if (a && a->reqopts && iface->dhcpv4_ntp_cnt != 0) {
                for(size_t opts = 0; a->reqopts[opts]; opts++) {
                        if (a->reqopts[opts] == DHCPV4_OPT_NTPSERVER) {
                                dhcpv4_put(&reply, &cookie, DHCPV4_OPT_NTPSERVER,