From: Mark Andrews <marka@isc.org>
Date: Sun, 4 Jul 2010 00:48:57 +0000 (+0000)
Subject: 2928.   [bug]           Be more selective about the non-authoritative
X-Git-Tag: v9.8.0-P1~600
X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=ff5864ef42c3bc55e9be20434d1f7de2f6794894;p=thirdparty%2Fbind9.git

2928.   [bug]           Be more selective about the non-authoritative
                        answer we apply change 2748 to. [RT #21594]
---

diff --git a/CHANGES b/CHANGES
index 4f135cfbf65..f88798aec40 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,6 @@
+2928.	[bug]		Be more selective about the non-authoritative
+			answer we apply change 2748 to. [RT #21594]
+
 2927.	[placeholder]
 
 2926.	[placeholder]
diff --git a/lib/dns/resolver.c b/lib/dns/resolver.c
index 1d07975eb84..f14b713abc9 100644
--- a/lib/dns/resolver.c
+++ b/lib/dns/resolver.c
@@ -15,7 +15,7 @@
  * PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: resolver.c,v 1.423 2010/06/23 23:46:58 tbox Exp $ */
+/* $Id: resolver.c,v 1.424 2010/07/04 00:48:57 marka Exp $ */
 
 /*! \file */
 
@@ -5628,7 +5628,7 @@ noanswer_response(fetchctx_t *fctx, dns_name_t *oqname,
 		 * trying other servers.
 		 */
 		if (dns_name_equal(ns_name, &fctx->domain)) {
-			log_formerr(fctx, "sideways referral");
+			log_formerr(fctx, "non-improving referral");
 			return (DNS_R_FORMERR);
 		}
 
@@ -6450,6 +6450,29 @@ iscname(fetchctx_t *fctx) {
 	return (result == ISC_R_SUCCESS ? ISC_TRUE : ISC_FALSE);
 }
 
+static isc_boolean_t
+betterreferral(fetchctx_t *fctx) {
+	isc_result_t result;
+	dns_name_t *name;
+	dns_rdataset_t *rdataset;
+	dns_message_t *message = fctx->rmessage;
+
+	for (result = dns_message_firstname(message, DNS_SECTION_AUTHORITY);
+	     result == ISC_R_SUCCESS;
+	     result = dns_message_nextname(message, DNS_SECTION_AUTHORITY)) {
+		name = NULL;
+		dns_message_currentname(message, DNS_SECTION_AUTHORITY, &name);
+		if (!dns_name_issubdomain(name, &fctx->domain))
+			continue;
+		for (rdataset = ISC_LIST_HEAD(name->list);
+		     rdataset != NULL;
+		     rdataset = ISC_LIST_NEXT(rdataset, link))
+			if (rdataset->type == dns_rdatatype_ns)
+				return (ISC_TRUE);
+	}
+	return (ISC_FALSE);
+}
+
 static void
 resquery_response(isc_task_t *task, isc_event_t *event) {
 	isc_result_t result = ISC_R_SUCCESS;
@@ -6929,6 +6952,12 @@ resquery_response(isc_task_t *task, isc_event_t *event) {
 			 * it as a valid answer.
 			 */
 			result = answer_response(fctx);
+		} else if (fctx->type != dns_rdatatype_ns &&
+			   !betterreferral(fctx)) {
+			/*
+			 * Lame response !!!.
+			 */
+			result = answer_response(fctx);
 		} else {
 			if (fctx->type == dns_rdatatype_ns) {
 				/*