333. [bug] The resolver incorrectly accepted referrals to

                        subdomains of the query domain, causing an
                        assertion failure.

CHANGES

+ 333.	[bug]		The resolver incorrectly accepted referrals to
+			subdomains of the query domain, causing an 
+			assertion failure.
+
  332.	[func]		New function dns_name_reset().
 
  331.	[bug]		Only log "recursion denied" if RD is set. (RT #178)

lib/dns/resolver.c

@@ -15,7 +15,7 @@
  * SOFTWARE.
  */
 
-/* $Id: resolver.c,v 1.147 2000/07/14 00:37:27 gson Exp $ */
+/* $Id: resolver.c,v 1.148 2000/07/15 01:02:25 gson Exp $ */
 
 #include <config.h>
 
@@ -2982,6 +2982,31 @@ dname_target(dns_rdataset_t *rdataset, dns_name_t *qname, dns_name_t *oname,
 	return (dns_name_concatenate(dname, &tname, dname, NULL));
 }
 
+/* XXXAG should be public function in name.c */
+
+static isc_boolean_t
+dns_name_ispropersubdomain(const dns_name_t *name1, const dns_name_t *name2) {
+	int order;
+	unsigned int nlabels, nbits;
+	dns_namereln_t namereln;
+
+	/*
+	 * Is 'name1' a proper subdomain of 'name2'?
+	 *
+	 * Note: It makes no sense for one of the names to be relative and the
+	 * other absolute.  If both names are relative, then to be meaningfully
+	 * compared the caller must ensure that they are both relative to the
+	 * same domain.
+	 */
+
+	namereln = dns_name_fullcompare(name1, name2, &order, &nlabels,
+					&nbits);
+	if (namereln == dns_namereln_subdomain)
+		return (ISC_TRUE);
+
+	return (ISC_FALSE);
+}
+
 static isc_result_t
 noanswer_response(fetchctx_t *fctx, dns_name_t *oqname) {
 	isc_result_t result;
@@ -3154,6 +3179,17 @@ noanswer_response(fetchctx_t *fctx, dns_name_t *oqname) {
 		 */
 		if (dns_name_equal(ns_name, &fctx->domain))
 			return (DNS_R_FORMERR);
+
+		/*
+		 * If the referral name is below the query name,
+		 * we are making too much progress, overshooting
+		 * the target.  Consider the responder insane.
+		 */
+		if (dns_name_ispropersubdomain(ns_name, &fctx->name)) {
+			FCTXTRACE("referral name below query name");
+			return (DNS_R_FORMERR);
+		}
+
 		/*
 		 * Mark any additional data related to this rdataset.
 		 * It's important that we do this before we change the