/*

 * Copyright (C) Internet Systems Consortium, Inc. ("ISC")

 *

 * SPDX-License-Identifier: MPL-2.0

 *

 * 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 https://mozilla.org/MPL/2.0/.

 *

 * See the COPYRIGHT file distributed with this work for additional

 * information regarding copyright ownership.

 */

/*! \file */

#include <string.h>

#include <isc/buffer.h>

#include <isc/md.h>

#include <isc/region.h>

#include <isc/result.h>

#include <isc/util.h>

#include <dns/ds.h>

#include <dns/fixedname.h>

#include <dns/keyvalues.h>

#include <dns/name.h>

#include <dns/rdata.h>

#include <dns/rdatastruct.h>

#include <dst/dst.h>

isc_result_t

dns_ds_fromkeyrdata(const dns_name_t *owner, dns_rdata_t *key,

        dns_dsdigest_t digest_type, unsigned char *digest,

        size_t len, dns_rdata_ds_t *dsrdata) {

  isc_result_t result;

  dns_fixedname_t fname;

  dns_name_t *name;

  unsigned int digestlen = 0;

  unsigned int privatelen = 0;

  isc_region_t r;

  isc_md_t *md;

  const isc_md_type_t *md_type = NULL;

  REQUIRE(key != NULL);

  REQUIRE(key->type == dns_rdatatype_dnskey ||

    key->type == dns_rdatatype_cdnskey);

  REQUIRE(digest != NULL);

  if (!dst_ds_digest_supported(digest_type)) {

    return ISC_R_NOTIMPLEMENTED;

  }

  switch (digest_type) {

  case DNS_DSDIGEST_SHA1:

    md_type = ISC_MD_SHA1;

    break;

  case DNS_DSDIGEST_SHA384:

#ifdef DNS_DSDIGEST_SHA384PRIVATE

  case DNS_DSDIGEST_SHA384PRIVATE:

#endif

    md_type = ISC_MD_SHA384;

    break;

  case DNS_DSDIGEST_SHA256:

#ifdef DNS_DSDIGEST_SHA256PRIVATE

  case DNS_DSDIGEST_SHA256PRIVATE:

#endif

    md_type = ISC_MD_SHA256;

    break;

  default:

    UNREACHABLE();

  }

  name = dns_fixedname_initname(&fname);

  (void)dns_name_downcase(owner, name);

  md = isc_md_new();

  result = isc_md_init(md, md_type);

  if (result != ISC_R_SUCCESS) {

    goto end;

  }

  dns_name_toregion(name, &r);

  result = isc_md_update(md, r.base, r.length);

  if (result != ISC_R_SUCCESS) {

    goto end;

  }

  dns_rdata_toregion(key, &r);

  INSIST(r.length >= 4);

  result = isc_md_update(md, r.base, r.length);

  if (result != ISC_R_SUCCESS) {

    goto end;

  }

#if defined(DNS_DSDIGEST_SHA256PRIVATE) && defined(DNS_DSDIGEST_SHA384PRIVATE)

  /*

   * Insert PRIVATE algorithm identify at start of digest.

   */

  switch (digest_type) {

  case DNS_DSDIGEST_SHA1:

  case DNS_DSDIGEST_SHA256:

  case DNS_DSDIGEST_SHA384:

    break;

  case DNS_DSDIGEST_SHA256PRIVATE:

  case DNS_DSDIGEST_SHA384PRIVATE:

    switch (r.base[3]) {

    case DNS_KEYALG_PRIVATEDNS: {

      isc_region_t r2 = r;

      INSIST(r2.length >= 5);

      isc_region_consume(&r2, 4);

      dns_name_fromregion(name, &r2);

      dns_name_toregion(name, &r2);

      privatelen = r2.length;

      if (r2.length > len) {

        result = ISC_R_NOSPACE;

        goto end;

      }

      memmove(digest, r2.base, privatelen);

      digest += privatelen;

      len -= privatelen;

      break;

    }

    case DNS_KEYALG_PRIVATEOID: {

      isc_region_t r2 = r;

      INSIST(r2.length >= 5);

      isc_region_consume(&r2, 4);

      privatelen = r2.base[0] + 1;

      if (r2.base[0] > len) {

        result = ISC_R_NOSPACE;

        goto end;

      }

      INSIST(r2.length >= privatelen);

      memmove(digest, r2.base, privatelen);

      digest += privatelen;

      len -= privatelen;

      break;

    }

    default:

      break;

    }

    break;

  default:

    break;

  }

#endif

  size_t mdsize = isc_md_get_size(md);

  if (mdsize > len) {

    result = ISC_R_NOSPACE;

    goto end;

  }

  result = isc_md_final(md, digest, &digestlen);

  if (result != ISC_R_SUCCESS) {

    goto end;

  }

  dsrdata->mctx = NULL;

  dsrdata->common.rdclass = key->rdclass;

  dsrdata->common.rdtype = dns_rdatatype_ds;

  dsrdata->algorithm = r.base[3];

  dsrdata->key_tag = dst_region_computeid(&r);

  dsrdata->digest_type = digest_type;

  dsrdata->digest = digest - privatelen;

  dsrdata->length = digestlen + privatelen;

end:

  isc_md_free(md);

  return result;

}

isc_result_t

dns_ds_buildrdata(dns_name_t *owner, dns_rdata_t *key,

      dns_dsdigest_t digest_type, unsigned char *buffer, size_t len,

      dns_rdata_t *rdata) {

  isc_result_t result;

  unsigned char digest[ISC_MAX_MD_SIZE];

  dns_rdata_ds_t ds;

  isc_buffer_t b;

  result = dns_ds_fromkeyrdata(owner, key, digest_type, digest, len, &ds);

  if (result != ISC_R_SUCCESS) {

    return result;

  }

  memset(buffer, 0, DNS_DS_BUFFERSIZE);

  isc_buffer_init(&b, buffer, DNS_DS_BUFFERSIZE);

  result = dns_rdata_fromstruct(rdata, key->rdclass, dns_rdatatype_ds,

              &ds, &b);

  return result;

}