From: Mark Andrews <marka@isc.org>
Date: Thu, 30 Jan 2025 22:09:33 +0000 (+1100)
Subject: Fix "CNAME and other data" detection
X-Git-Tag: ondrej/lock-free-qpzone-reads-v1~61^2~2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5e49a9e4ae8d0a78fb5ac0c7b683de9a29b6b848;p=thirdparty%2Fbind9.git

Fix "CNAME and other data" detection

prio_type was being used in the wrong place to optimize cname_and_other.
We have to first exclude and accepted types and we also have to
determine that the record exists before we can check if we are at
a point where a later CNAME cannot appear.
---

diff --git a/lib/dns/qpzone.c b/lib/dns/qpzone.c
index e0ddab3bfbf..14ede511ab5 100644
--- a/lib/dns/qpzone.c
+++ b/lib/dns/qpzone.c
@@ -1727,15 +1727,6 @@ cname_and_other(qpznode_t *node, uint32_t serial) {
 	for (header = node->data; header != NULL; header = header_next) {
 		header_next = header->next;
 
-		if (!prio_type(header->type)) {
-			/*
-			 * CNAME is in the priority list, so if we are done
-			 * with priority types, we know there will not be a
-			 * CNAME, and are safe to skip the rest.
-			 */
-			return false;
-		}
-
 		rdtype = DNS_TYPEPAIR_TYPE(header->type);
 		if (rdtype == dns_rdatatype_cname) {
 			do {
@@ -1767,6 +1758,15 @@ cname_and_other(qpznode_t *node, uint32_t serial) {
 				header = header->down;
 			} while (header != NULL);
 			if (header != NULL) {
+				if (!prio_type(header->type)) {
+					/*
+					 * CNAME is in the priority list, so if
+					 * we are done with priority types, we
+					 * know there will not be a CNAME, and
+					 * are safe to skip the rest.
+					 */
+					return cname;
+				}
 				other = true;
 			}
 		}