Fix bug added in 2.80 non-terminal code which returns NODATA instead of NXDOMAIN.

Thanks to Sven Muleller and Maciej Żenczykowski for work on this.

https://bugzilla.redhat.com/show_bug.cgi?id=1674067 refers.

CHANGELOG

@@ -21,6 +21,11 @@ version 2.81
 	correct error messages. Thanks to Christian Rosentreter
 	for reporting this.
 
+	Fix bug in DNS non-terminal code, added in 2.80, which could
+	sometimes cause a NODATA rather than an NXDOMAIN reply.
+	Thanks to Sven Mueller and Maciej Żenczykowski for spotting
+	and diagnosing the bug and providing patches.
+
 
 version 2.80
 	Add support for RFC 4039 DHCP rapid commit. Thanks to Ashram Method

src/cache.c

@@ -790,6 +790,7 @@ int cache_find_non_terminal(char *name, time_t now)
     if (!is_outdated_cname_pointer(crecp) &&
 	!is_expired(now, crecp) &&
 	(crecp->flags & F_FORWARD) &&
+	!(crecp->flags & F_NXDOMAIN) && 
 	hostname_isequal(name, cache_get_name(crecp)))
       return 1;