Check for NULL before de-referencing a pointer, not after.

More complete solution after tb@ pointed out what Coverity missed.

ok tb@

diff --git a/sys/netinet6/nd6_nbr.c b/sys/netinet6/nd6_nbr.c
index 92cc4e3..e2fccc4 100644 (file)
--- a/sys/netinet6/nd6_nbr.c
+++ b/sys/netinet6/nd6_nbr.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: nd6_nbr.c,v 1.150 2023/07/29 15:59:27 krw Exp $       */
+/*     $OpenBSD: nd6_nbr.c,v 1.151 2023/07/30 12:52:03 krw Exp $       */
 /*     $KAME: nd6_nbr.c,v 1.61 2001/02/10 16:06:14 jinmei Exp $        */
 
 /*
@@ -1158,21 +1158,24 @@ nd6_dad_stop(struct ifaddr *ifa)
 void
 nd6_dad_timer(void *xifa)
 {
-       struct ifaddr *ifa = xifa;
-       struct in6_ifaddr *ia6 = ifatoia6(ifa);
+       struct ifaddr *ifa;
+       struct in6_ifaddr *ia6;
        struct in6_addr daddr6, taddr6;
-       struct ifnet *ifp = ifa->ifa_ifp;
+       struct ifnet *ifp;
        struct dadq *dp;
        char addr[INET6_ADDRSTRLEN];
 
        NET_LOCK();
 
        /* Sanity check */
-       if (ia6 == NULL) {
+       if (xifa == NULL) {
                log(LOG_ERR, "%s: called with null parameter\n", __func__);
                goto done;
        }
+       ifa = xifa;
+       ia6 = ifatoia6(ifa);
        taddr6 = ia6->ia_addr.sin6_addr;
+       ifp = ifa->ifa_ifp;
        dp = nd6_dad_find(ifa);
        if (dp == NULL) {
                log(LOG_ERR, "%s: DAD structure not found\n", __func__);