Check that primary key names are syntactically valid

bin/tests/system/checkconf/bad-primaries-key.conf

@@ -0,0 +1,15 @@
+/*
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+zone example {
+        type secondary;
+        primaries { 1.2.3.4 key a..b; };
+};

lib/bind9/check.c

@@ -2121,6 +2121,20 @@ resume:
 
 		if (cfg_obj_issockaddr(addr)) {
 			count++;
+			if (cfg_obj_isstring(key)) {
+				const char *str = cfg_obj_asstring(key);
+				dns_fixedname_t fname;
+				dns_name_t *nm = dns_fixedname_initname(&fname);
+				tresult = dns_name_fromstring(nm, str, 0, NULL);
+				if (tresult != ISC_R_SUCCESS) {
+					cfg_obj_log(key, logctx, ISC_LOG_ERROR,
+						    "'%s' is not a valid name",
+						    str);
+					if (result == ISC_R_SUCCESS) {
+						result = tresult;
+					}
+				}
+			}
 			continue;
 		}
 		if (!cfg_obj_isvoid(key)) {