From: Ondřej Surý <ondrej@sury.org>
Date: Sun, 12 Jul 2026 05:00:31 +0000 (+0200)
Subject: Skip non-existent qpcache headers in iterators
X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=0f551cea5dbcb19e7a5bc0b019625b4b2afa5cda;p=thirdparty%2Fbind9.git

Skip non-existent qpcache headers in iterators

The cache rdataset iterator must never bind delete tombstones, even
when expired cache entries are requested for dumpdb. Treat non-existent
slab headers as inactive so expired dumps cannot expose headers without
a backing rdataslab.

Assisted-by: Codex:GPT-5
---

diff --git a/lib/dns/qpcache.c b/lib/dns/qpcache.c
index 72ad867e3c1..ad0768d36f9 100644
--- a/lib/dns/qpcache.c
+++ b/lib/dns/qpcache.c
@@ -2101,7 +2101,9 @@ qpcache_createiterator(dns_db_t *db, unsigned int options ISC_ATTR_UNUSED,
 static bool
 iterator_active(qpcache_t *qpdb, qpc_rditer_t *iterator,
 		dns_slabheader_t *header) {
-	dns_ttl_t stale_ttl = header->expire + STALE_TTL(header, qpdb);
+	if (!EXISTS(header)) {
+		return false;
+	}
 
 	/*
 	 * If this header is still active then return it.
@@ -2110,6 +2112,8 @@ iterator_active(qpcache_t *qpdb, qpc_rditer_t *iterator,
 		return true;
 	}
 
+	dns_ttl_t stale_ttl = header->expire + STALE_TTL(header, qpdb);
+
 	/*
 	 * If we are not returning stale records or the rdataset is
 	 * too old don't return it.
@@ -2150,6 +2154,9 @@ qpcache_allrdatasets(dns_db_t *db, dns_dbnode_t *node, dns_dbversion_t *version,
 	NODE_RDLOCK(nlock, &nlocktype);
 
 	DNS_SLABHEADER_FOREACH(header, &qpnode->headers) {
+		if (!EXISTS(header)) {
+			continue;
+		}
 		if (EXPIREDOK(iterator) ||
 		    iterator_active(qpdb, iterator, header))
 		{