diff -up bind-9.3.6-P1/bin/named/query.c.CVE-2012-5166 bind-9.3.6-P1/bin/named/query.c
--- bind-9.3.6-P1/bin/named/query.c.CVE-2012-5166	2012-10-10 02:18:11.120440792 +0200
+++ bind-9.3.6-P1/bin/named/query.c	2012-10-10 02:25:59.575599005 +0200
@@ -856,13 +856,6 @@ query_isduplicate(ns_client_t *client, d
 		mname = NULL;
 	}
 
-	/*
-	 * If the dns_name_t we're looking up is already in the message,
-	 * we don't want to trigger the caller's name replacement logic.
-	 */
-	if (name == mname)
-		mname = NULL;
-
 	*mnamep = mname;
 
 	CTRACE("query_isduplicate: false: done");
@@ -1042,6 +1035,7 @@ query_addadditional(void *arg, dns_name_
 	if (dns_rdataset_isassociated(rdataset) &&
 	    !query_isduplicate(client, fname, type, &mname)) {
 		if (mname != NULL) {
+			INSIST(mname != fname);
 			query_releasename(client, &fname);
 			fname = mname;
 		} else
@@ -1102,11 +1096,13 @@ query_addadditional(void *arg, dns_name_
 			mname = NULL;
 			if (!query_isduplicate(client, fname,
 					       dns_rdatatype_a, &mname)) {
-				if (mname != NULL) {
-					query_releasename(client, &fname);
-					fname = mname;
-				} else
-					need_addname = ISC_TRUE;
+				if (mname != fname) {
+					if (mname != NULL) {
+						query_releasename(client, &fname);
+						fname = mname;
+					} else
+						need_addname = ISC_TRUE;
+				}
 				ISC_LIST_APPEND(fname->list, rdataset, link);
 				added_something = ISC_TRUE;
 				if (sigrdataset != NULL &&
@@ -1145,11 +1141,13 @@ query_addadditional(void *arg, dns_name_
 			mname = NULL;
 			if (!query_isduplicate(client, fname,
 					       dns_rdatatype_aaaa, &mname)) {
-				if (mname != NULL) {
-					query_releasename(client, &fname);
-					fname = mname;
-				} else
-					need_addname = ISC_TRUE;
+				if (mname != fname) {
+					if (mname != NULL) {
+						query_releasename(client, &fname);
+						fname = mname;
+					} else
+						need_addname = ISC_TRUE;
+				}
 				ISC_LIST_APPEND(fname->list, rdataset, link);
 				added_something = ISC_TRUE;
 				if (sigrdataset != NULL &&