From: Evan Hunt <each@isc.org>
Date: Thu, 27 Sep 2012 00:32:45 +0000 (-0700)
Subject: fixed an exploitable hang bug
X-Git-Tag: v9.8.4^0
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5dffd984bf533910e6a90f0621a15dab676d0ad2;p=thirdparty%2Fbind9.git

fixed an exploitable hang bug

3383.	[security]	A certain combination of records in the RBT could
                        cause named to hang while populating the additional
                        section of a response. [RT #31090]
---

diff --git a/CHANGES b/CHANGES
index b670f798ea8..801f9918e5f 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,5 +1,9 @@
 	--- 9.8.4 released ---
 
+3383.	[security]	A certain combination of records in the RBT could
+                        cause named to hang while populating the additional
+                        section of a response. [RT #31090]
+
 3373.	[bug]		win32: open raw files in binary mode. [RT #30944]
 
 3364.	[security]	Named could die on specially crafted record.
diff --git a/bin/named/query.c b/bin/named/query.c
index b717761feed..2bdaac820e4 100644
--- a/bin/named/query.c
+++ b/bin/named/query.c
@@ -1120,13 +1120,6 @@ query_isduplicate(ns_client_t *client, dns_name_t *name,
 		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;
-
 	if (mnamep != NULL)
 		*mnamep = mname;
 
@@ -1325,6 +1318,7 @@ query_addadditional(void *arg, dns_name_t *name, dns_rdatatype_t qtype) {
 	if (dns_rdataset_isassociated(rdataset) &&
 	    !query_isduplicate(client, fname, type, &mname)) {
 		if (mname != NULL) {
+			INSIST(mname != fname);
 			query_releasename(client, &fname);
 			fname = mname;
 		} else
@@ -1394,11 +1388,13 @@ query_addadditional(void *arg, dns_name_t *name, dns_rdatatype_t qtype) {
 #endif
 			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 &&
@@ -1451,11 +1447,13 @@ query_addadditional(void *arg, dns_name_t *name, dns_rdatatype_t qtype) {
 #endif
 			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 &&
@@ -1978,22 +1976,24 @@ query_addadditional2(void *arg, dns_name_t *name, dns_rdatatype_t qtype) {
 		    crdataset->type == dns_rdatatype_aaaa) {
 			if (!query_isduplicate(client, fname, crdataset->type,
 					       &mname)) {
-				if (mname != NULL) {
-					/*
-					 * A different type of this name is
-					 * already stored in the additional
-					 * section.  We'll reuse the name.
-					 * Note that this should happen at most
-					 * once.  Otherwise, fname->link could
-					 * leak below.
-					 */
-					INSIST(mname0 == NULL);
-
-					query_releasename(client, &fname);
-					fname = mname;
-					mname0 = mname;
-				} else
-					need_addname = ISC_TRUE;
+				if (mname != fname) {
+					if (mname != NULL) {
+						/*
+						 * A different type of this name is
+						 * already stored in the additional
+						 * section.  We'll reuse the name.
+						 * Note that this should happen at most
+						 * once.  Otherwise, fname->link could
+						 * leak below.
+						 */
+						INSIST(mname0 == NULL);
+
+						query_releasename(client, &fname);
+						fname = mname;
+						mname0 = mname;
+					} else
+						need_addname = ISC_TRUE;
+				}
 				ISC_LIST_UNLINK(cfname.list, crdataset, link);
 				ISC_LIST_APPEND(fname->list, crdataset, link);
 				added_something = ISC_TRUE;