fix CVE-2023-2911

backport-CVE-2023-2911.patch

@@ -0,0 +1,107 @@
+From 240caa32b9cab90a38ab863fd64e6becf5d1393c Mon Sep 17 00:00:00 2001
+From: Evan Hunt <each@isc.org>
+Date: Thu, 25 May 2023 23:53:50 -0700
+Subject: [PATCH] Stale answer lookups could loop when over recursion quota
+
+When a query was aborted because of the recursion quota being exceeded,
+but triggered a stale answer response and a stale data refresh query,
+it could cause named to loop back where we are iterating and following
+a delegation. Having no good answer in cache, we would fall back to
+using serve-stale again, use the stale data, try to refresh the RRset,
+and loop back again, without ever terminating until crashing due to
+stack overflow.
+
+This happens because in the functions 'query_notfound()' and
+'query_delegation_recurse()', we check whether we can fall back to
+serving stale data. We shouldn't do so if we are already refreshing
+an RRset due to having prioritized stale data in cache.
+
+In other words, we need to add an extra check to 'query_usestale()' to
+disallow serving stale data if we are currently refreshing a stale
+RRset.
+
+As an additional mitigation to prevent looping, we now use the result
+code ISC_R_ALREADYRUNNING rather than ISC_R_FAILURE when a recursion
+loop is encountered, and we check for that condition in
+'query_usestale()' as well.
+
+---
+ lib/ns/query.c | 30 ++++++++++++++++++++++--------
+ 1 file changed, 22 insertions(+), 8 deletions(-)
+
+diff --git a/lib/ns/query.c b/lib/ns/query.c
+index 1444de5..3ce6742 100644
+--- a/lib/ns/query.c
++++ b/lib/ns/query.c
+@@ -5696,6 +5696,7 @@ query_refresh_rrset(query_ctx_t *orig_qctx) {
+ 	qctx.client->query.dboptions &= ~(DNS_DBFIND_STALETIMEOUT |
+ 					  DNS_DBFIND_STALEOK |
+ 					  DNS_DBFIND_STALEENABLED);
++	qctx.client->nodetach = false;
+ 
+ 	/*
+ 	 * We'll need some resources...
+@@ -5920,7 +5921,14 @@ query_lookup(query_ctx_t *qctx) {
+ 					"%s stale answer used, an attempt to "
+ 					"refresh the RRset will still be made",
+ 					namebuf);
++
+ 				qctx->refresh_rrset = STALE(qctx->rdataset);
++
++				/*
++				 * If we are refreshing the RRSet, we must not
++				 * detach from the client in query_send().
++				 */
++				qctx->client->nodetach = qctx->refresh_rrset;
+ 			}
+ 		} else {
+ 			/*
+@@ -6272,7 +6280,7 @@ ns_query_recurse(ns_client_t *client, dns_rdatatype_t qtype, dns_name_t *qname,
+ 	if (recparam_match(&client->query.recparam, qtype, qname, qdomain)) {
+ 		ns_client_log(client, NS_LOGCATEGORY_CLIENT, NS_LOGMODULE_QUERY,
+ 			      ISC_LOG_INFO, "recursion loop detected");
+-		return (ISC_R_FAILURE);
++		return (ISC_R_ALREADYRUNNING);
+ 	}
+ 
+ 	recparam_update(&client->query.recparam, qtype, qname, qdomain);
+@@ -7235,10 +7243,21 @@ query_usestale(query_ctx_t *qctx, isc_result_t result) {
+ 		return (false);
+ 	}
+ 
+-	if (result == DNS_R_DUPLICATE || result == DNS_R_DROP) {
++	if (qctx->refresh_rrset) {
++		/*
++		 * This is a refreshing query, we have already prioritized
++		 * stale data, so don't enable serve-stale again.
++		 */
++		return (false);
++	}
++
++	if (result == DNS_R_DUPLICATE || result == DNS_R_DROP ||
++	    result == ISC_R_ALREADYRUNNING)
++	{
+ 		/*
+ 		 * Don't enable serve-stale if the result signals a duplicate
+-		 * query or query that is being dropped.
++		 * query or a query that is being dropped or can't proceed
++		 * because of a recursion loop.
+ 		 */
+ 		return (false);
+ 	}
+@@ -11490,12 +11509,7 @@ ns_query_done(query_ctx_t *qctx) {
+ 	/*
+ 	 * Client may have been detached after query_send(), so
+ 	 * we test and store the flag state here, for safety.
+-	 * If we are refreshing the RRSet, we must not detach from the client
+-	 * in the query_send(), so we need to override the flag.
+ 	 */
+-	if (qctx->refresh_rrset) {
+-		qctx->client->nodetach = true;
+-	}
+ 	nodetach = qctx->client->nodetach;
+ 	query_send(qctx->client);
+ 
+-- 
+2.33.0
+

bind.spec

@@ -30,7 +30,7 @@ Summary:  The Berkeley Internet Name Domain (BIND) DNS (Domain Name System) serv
 Name:     bind
 License:  MPLv2.0
 Version:  9.16.37
-Release:  4
+Release:  5
 Epoch:    32
 Url:      https://www.isc.org/downloads/bind/
 #
@@ -78,6 +78,7 @@ Patch17: bind-9.11-rh1666814.patch
 Patch18: bind-9.18-zt-include-rwlock.patch
 
 Patch6001: CVE-2022-2906.patch
+Patch6002: backport-CVE-2023-2911.patch
 
 Patch9000: bugfix-limit-numbers-of-test-threads.patch
 
@@ -1089,6 +1090,12 @@ fi;
 %endif
 
 %changelog
+* Mon Sep 25 2023 zhanghao<zhanghao383@huawei.com> - 32:9.16.37-5
+- Type:CVE
+- CVE:CVE-2023-2911
+- SUG:NA
+- DESC:fix CVE-2023-2911
+
 * Tue Feb 14 2023 zhanghao<zhanghao383@huawei.com> - 32:9.16.37-4
 - Type:requirement
 - CVE:NA