From 0ae8b2e056c3e24df0746541c505bc358352f7fa Mon Sep 17 00:00:00 2001
From: Evan Hunt <each@isc.org>
Date: Thu, 18 May 2023 22:02:06 -0700
Subject: [PATCH] prevent query_coveringnsec() from running twice

when synthesizing a new CNAME, we now check whether the target
matches the query already being processed. if so, we do not
restart the query; this prevents a waste of resources.
---
 lib/ns/query.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/lib/ns/query.c b/lib/ns/query.c
index 8edfc9814c..0b3d359d17 100644
--- a/lib/ns/query.c
+++ b/lib/ns/query.c
@@ -9870,6 +9870,12 @@ query_synthcnamewildcard(query_ctx_t *qctx, dns_rdataset_t *rdataset,
 	RUNTIME_CHECK(result == ISC_R_SUCCESS);
 	dns_rdata_reset(&rdata);
 
+	if (dns_name_equal(qctx->client->query.qname, &cname.cname)) {
+		dns_message_puttempname(qctx->client->message, &tname);
+		dns_rdata_freestruct(&cname);
+		return (ISC_R_SUCCESS);
+	}
+
 	dns_name_copy(&cname.cname, tname);
 
 	dns_rdata_freestruct(&cname);