From: Willem Toorop <willem@nlnetlabs.nl>
Date: Thu, 22 Jan 2026 20:09:01 +0000 (+0100)
Subject: -O option to ldns-signzone to only calc ZONEMD
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;p=thirdparty%2Fldns.git

-O option to ldns-signzone to only calc ZONEMD
---

diff --git a/Changelog b/Changelog
index bd5290c1..b32d92ac 100644
--- a/Changelog
+++ b/Changelog
@@ -6,6 +6,8 @@
 	  error, when size is 0
 	* Fix to reserve enough space to convert the largest packets to
 	  presentation format in ldns_pkt2str_fmt. Thanks Peter Kästle
+	* The -O option to calculate (and sign) only the ZONEMD an input
+	  zone with ldns-signzone
 	
 1.9.0	2025-12-04
 	* PR #246: Make ldns_calc_keytag() available for CDNSKEY RR
diff --git a/dnssec_zone.c b/dnssec_zone.c
index ef2359bb..d38f45b3 100644
--- a/dnssec_zone.c
+++ b/dnssec_zone.c
@@ -1930,9 +1930,6 @@ rr_list2dnssec_rrs(ldns_rr_list *rr_list, ldns_dnssec_rrs **rrs,
 }
 
 
-ldns_status
-dnssec_zone_equip_zonemd(ldns_dnssec_zone *zone,
-		ldns_rr_list *new_rrs, ldns_key_list *key_list, int signflags);
 ldns_status
 dnssec_zone_equip_zonemd(ldns_dnssec_zone *zone,
 		ldns_rr_list *new_rrs, ldns_key_list *key_list, int signflags)
@@ -1989,6 +1986,13 @@ dnssec_zone_equip_zonemd(ldns_dnssec_zone *zone,
 		zonemd_rrset->next = *rrset_ref;
 		*rrset_ref = zonemd_rrset;
 	}
+	if (signflags & LDNS_SIGN_ONLY_ZONEMD) {
+		size_t i;
+
+		for (i = 0; i < ldns_key_list_key_count(key_list); i++) {
+			ldns_key_set_use(ldns_key_list_key(key_list, i), true);
+		}
+	}
 	if ((zonemd_rrsigs = ldns_sign_public(zonemd_rr_list, key_list)))
 		st = rr_list2dnssec_rrs(  zonemd_rrsigs
 		                       , &zonemd_rrset->signatures, new_rrs);
diff --git a/examples/ldns-signzone.1 b/examples/ldns-signzone.1
index dc0a776e..ac33f54c 100644
--- a/examples/ldns-signzone.1
+++ b/examples/ldns-signzone.1
@@ -80,6 +80,10 @@ Calculate the zone's digest and add those as ZONEMD RRs. The (optional)
 \fB-Z\fR
 Allow ZONEMDs to be added without signing
 
+.TP
+\fB-O\fR
+Only calculate (and sign) the ZONEMD for the input zone
+
 .TP
 \fB-A\fR
 Sign the DNSKEY record with all keys.  By default it is signed with a
diff --git a/examples/ldns-signzone.c b/examples/ldns-signzone.c
index 509a023d..294bcf36 100644
--- a/examples/ldns-signzone.c
+++ b/examples/ldns-signzone.c
@@ -53,6 +53,7 @@ usage(FILE *fp, const char *prog) {
 	fprintf(fp, "\t\t<hash> should be \"sha384\" or \"sha512\" (or 1 or 2)\n");
 	fprintf(fp, "\t\tthis option can be given more than once\n");
 	fprintf(fp, "  -Z\t\tAllow ZONEMDs to be added without signing\n");
+	fprintf(fp, "  -O\t\tOnly calculate (and sign) the ZONEMD for the input zone\n");
 	fprintf(fp, "  -A\t\tsign DNSKEY with all keys instead of minimal\n");
 	fprintf(fp, "  -U\t\tSign with every unique algorithm in the provided keys\n");
 #ifndef OPENSSL_NO_ENGINE
@@ -673,7 +674,7 @@ main(int argc, char *argv[])
 	
 	keys = ldns_key_list_new();
 
-	while ((c = getopt(argc, argv, "a:bde:f:i:k:no:ps:t:uvz:ZAUE:K:")) != -1) {
+	while ((c = getopt(argc, argv, "a:bde:f:i:k:no:ps:t:uvz:ZOAUE:K:")) != -1) {
 		switch (c) {
 		case 'a':
 			nsec3_algorithm = (uint8_t) atoi(optarg);
@@ -780,6 +781,9 @@ main(int argc, char *argv[])
 		case 'Z':
 			signflags |= LDNS_SIGN_NO_KEYS_NO_NSECS;
 			break;
+		case 'O':
+			signflags |= LDNS_SIGN_ONLY_ZONEMD;
+			break;
 		case 'A':
 			signflags |= LDNS_SIGN_DNSKEY_WITH_ZSK;
 			break;
@@ -1051,7 +1055,9 @@ main(int argc, char *argv[])
 		result = ldns_dnssec_zone_sign_nsec3_flg_mkmap(signed_zone,
 			added_rrs,
 			keys,
-			ldns_dnssec_default_replace_signatures,
+			( signflags & LDNS_SIGN_ONLY_ZONEMD
+			? ldns_dnssec_default_leave_signatures
+			: ldns_dnssec_default_replace_signatures ),
 			NULL,
 			nsec3_algorithm,
 			nsec3_flags,
@@ -1064,7 +1070,9 @@ main(int argc, char *argv[])
 		result = ldns_dnssec_zone_sign_flg(signed_zone,
 				added_rrs,
 				keys,
-				ldns_dnssec_default_replace_signatures,
+				( signflags & LDNS_SIGN_ONLY_ZONEMD
+				? ldns_dnssec_default_leave_signatures
+				: ldns_dnssec_default_replace_signatures ),
 				NULL,
 				signflags);
 	}
diff --git a/ldns/dnssec_sign.h b/ldns/dnssec_sign.h
index 4523811f..8ccce101 100644
--- a/ldns/dnssec_sign.h
+++ b/ldns/dnssec_sign.h
@@ -17,6 +17,7 @@ extern "C" {
 #define LDNS_SIGN_NO_KEYS_NO_NSECS           4
 #define LDNS_SIGN_WITH_ZONEMD_SIMPLE_SHA384  8
 #define LDNS_SIGN_WITH_ZONEMD_SIMPLE_SHA512 16
+#define LDNS_SIGN_ONLY_ZONEMD               32
 
 /**
  * Create an empty RRSIG RR (i.e. without the actual signature data)