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      1 /*	$NetBSD: ds.c,v 1.10 2025/01/26 16:25:22 christos Exp $	*/
      2 
      3 /*
      4  * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
      5  *
      6  * SPDX-License-Identifier: MPL-2.0
      7  *
      8  * This Source Code Form is subject to the terms of the Mozilla Public
      9  * License, v. 2.0. If a copy of the MPL was not distributed with this
     10  * file, you can obtain one at https://mozilla.org/MPL/2.0/.
     11  *
     12  * See the COPYRIGHT file distributed with this work for additional
     13  * information regarding copyright ownership.
     14  */
     15 
     16 /*! \file */
     17 
     18 #include <string.h>
     19 
     20 #include <isc/buffer.h>
     21 #include <isc/md.h>
     22 #include <isc/region.h>
     23 #include <isc/result.h>
     24 #include <isc/util.h>
     25 
     26 #include <dns/ds.h>
     27 #include <dns/fixedname.h>
     28 #include <dns/name.h>
     29 #include <dns/rdata.h>
     30 #include <dns/rdatastruct.h>
     31 
     32 #include <dst/dst.h>
     33 
     34 isc_result_t
     35 dns_ds_fromkeyrdata(const dns_name_t *owner, dns_rdata_t *key,
     36 		    dns_dsdigest_t digest_type, unsigned char *digest,
     37 		    dns_rdata_ds_t *dsrdata) {
     38 	isc_result_t result;
     39 	dns_fixedname_t fname;
     40 	dns_name_t *name;
     41 	unsigned int digestlen;
     42 	isc_region_t r;
     43 	isc_md_t *md;
     44 	const isc_md_type_t *md_type = NULL;
     45 
     46 	REQUIRE(key != NULL);
     47 	REQUIRE(key->type == dns_rdatatype_dnskey ||
     48 		key->type == dns_rdatatype_cdnskey);
     49 
     50 	if (!dst_ds_digest_supported(digest_type)) {
     51 		return ISC_R_NOTIMPLEMENTED;
     52 	}
     53 
     54 	switch (digest_type) {
     55 	case DNS_DSDIGEST_SHA1:
     56 		md_type = ISC_MD_SHA1;
     57 		break;
     58 
     59 	case DNS_DSDIGEST_SHA384:
     60 		md_type = ISC_MD_SHA384;
     61 		break;
     62 
     63 	case DNS_DSDIGEST_SHA256:
     64 		md_type = ISC_MD_SHA256;
     65 		break;
     66 
     67 	default:
     68 		UNREACHABLE();
     69 	}
     70 
     71 	name = dns_fixedname_initname(&fname);
     72 	(void)dns_name_downcase(owner, name, NULL);
     73 
     74 	md = isc_md_new();
     75 	if (md == NULL) {
     76 		return ISC_R_NOMEMORY;
     77 	}
     78 
     79 	result = isc_md_init(md, md_type);
     80 	if (result != ISC_R_SUCCESS) {
     81 		goto end;
     82 	}
     83 
     84 	dns_name_toregion(name, &r);
     85 
     86 	result = isc_md_update(md, r.base, r.length);
     87 	if (result != ISC_R_SUCCESS) {
     88 		goto end;
     89 	}
     90 
     91 	dns_rdata_toregion(key, &r);
     92 	INSIST(r.length >= 4);
     93 
     94 	result = isc_md_update(md, r.base, r.length);
     95 	if (result != ISC_R_SUCCESS) {
     96 		goto end;
     97 	}
     98 
     99 	result = isc_md_final(md, digest, &digestlen);
    100 	if (result != ISC_R_SUCCESS) {
    101 		goto end;
    102 	}
    103 
    104 	dsrdata->mctx = NULL;
    105 	dsrdata->common.rdclass = key->rdclass;
    106 	dsrdata->common.rdtype = dns_rdatatype_ds;
    107 	dsrdata->algorithm = r.base[3];
    108 	dsrdata->key_tag = dst_region_computeid(&r);
    109 	dsrdata->digest_type = digest_type;
    110 	dsrdata->digest = digest;
    111 	dsrdata->length = digestlen;
    112 
    113 end:
    114 	isc_md_free(md);
    115 	return result;
    116 }
    117 
    118 isc_result_t
    119 dns_ds_buildrdata(dns_name_t *owner, dns_rdata_t *key,
    120 		  dns_dsdigest_t digest_type, unsigned char *buffer,
    121 		  dns_rdata_t *rdata) {
    122 	isc_result_t result;
    123 	unsigned char digest[ISC_MAX_MD_SIZE];
    124 	dns_rdata_ds_t ds;
    125 	isc_buffer_t b;
    126 
    127 	result = dns_ds_fromkeyrdata(owner, key, digest_type, digest, &ds);
    128 	if (result != ISC_R_SUCCESS) {
    129 		return result;
    130 	}
    131 
    132 	memset(buffer, 0, DNS_DS_BUFFERSIZE);
    133 	isc_buffer_init(&b, buffer, DNS_DS_BUFFERSIZE);
    134 	result = dns_rdata_fromstruct(rdata, key->rdclass, dns_rdatatype_ds,
    135 				      &ds, &b);
    136 	return result;
    137 }
    138