/* 

   Unix SMB/CIFS implementation.

   auto-generate self signed TLS certificates

   Copyright (C) Andrew Tridgell 2005

   This program is free software; you can redistribute it and/or modify

   it under the terms of the GNU General Public License as published by

   the Free Software Foundation; either version 3 of the License, or

   (at your option) any later version.

   This program is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License

   along with this program.  If not, see <http://www.gnu.org/licenses/>.

*/

#include "includes.h"

#include "lib/util/util_file.h"

#include "lib/tls/tls.h"

#include <gnutls/gnutls.h>

#include <gnutls/x509.h>

#define ORGANISATION_NAME "Samba Administration"

#define CA_NAME           "Samba - temporary autogenerated CA certificate"

#define UNIT_NAME         "Samba - temporary autogenerated HOST certificate"

#define LIFETIME          700*24*60*60

/* FIPS140-2 only allows 2048 or 3072 prime sizes. */

#define RSA_BITS gnutls_fips140_mode_enabled() ? 3072 : 4096

/* 

   auto-generate a set of self signed certificates

*/

void tls_cert_generate(TALLOC_CTX *mem_ctx, 

           const char *hostname, 

           const char * const *additional_hostnames,

           const char *keyfile, const char *certfile,

           const char *cafile)

{

  gnutls_x509_crt_t cacrt, crt;

  gnutls_x509_privkey_t key, cakey;

  uint8_t serial[8];

  unsigned char keyid[100];

  char buf[4096];

  size_t bufsize;

  size_t keyidsize = sizeof(keyid);

  time_t activation = time(NULL), expiry = activation + LIFETIME;

  size_t adhn_idx;

  int ret;

  if (file_exist(keyfile) || file_exist(certfile) || file_exist(cafile)) {

    DEBUG(0,("TLS autogeneration skipped - some TLS files already exist\n"));

    return;

  }

#define TLSCHECK(call) do { \

  ret = call; \

  if (ret < 0) { \

    DEBUG(0,("TLS %s - %s\n", #call, gnutls_strerror(ret))); \

    goto failed; \

  } \

} while (0)

  DEBUG(0,("Attempting to autogenerate TLS self-signed keys for https for hostname '%s'\n", 

     hostname));

  DEBUG(3,("Generating private key\n"));

  TLSCHECK(gnutls_x509_privkey_init(&key));

  TLSCHECK(gnutls_x509_privkey_generate(key,   GNUTLS_PK_RSA, RSA_BITS, 0));

  DEBUG(3,("Generating CA private key\n"));

  TLSCHECK(gnutls_x509_privkey_init(&cakey));

  TLSCHECK(gnutls_x509_privkey_generate(cakey, GNUTLS_PK_RSA, RSA_BITS, 0));

  DEBUG(3,("Generating CA certificate\n"));

  TLSCHECK(gnutls_x509_crt_init(&cacrt));

  TLSCHECK(gnutls_x509_crt_set_dn_by_oid(cacrt, 

              GNUTLS_OID_X520_ORGANIZATION_NAME, 0,

              ORGANISATION_NAME, strlen(ORGANISATION_NAME)));

  TLSCHECK(gnutls_x509_crt_set_dn_by_oid(cacrt, 

              GNUTLS_OID_X520_ORGANIZATIONAL_UNIT_NAME, 0,

              CA_NAME, strlen(CA_NAME)));

  TLSCHECK(gnutls_x509_crt_set_dn_by_oid(cacrt,

              GNUTLS_OID_X520_COMMON_NAME, 0,

              hostname, strlen(hostname)));

  TLSCHECK(gnutls_x509_crt_set_key(cacrt, cakey));

  PUSH_BE_U64(serial, 0, time(NULL));

  TLSCHECK(gnutls_x509_crt_set_serial(cacrt, &serial, sizeof(serial)));

  TLSCHECK(gnutls_x509_crt_set_activation_time(cacrt, activation));

  TLSCHECK(gnutls_x509_crt_set_expiration_time(cacrt, expiry));

  TLSCHECK(gnutls_x509_crt_set_ca_status(cacrt, 1));

  TLSCHECK(gnutls_x509_crt_set_key_usage(cacrt, GNUTLS_KEY_KEY_CERT_SIGN | GNUTLS_KEY_CRL_SIGN));

  TLSCHECK(gnutls_x509_crt_set_version(cacrt, 3));

  TLSCHECK(gnutls_x509_crt_get_key_id(cacrt, 0, keyid, &keyidsize));

  TLSCHECK(gnutls_x509_crt_set_subject_key_id(cacrt, keyid, keyidsize));

  TLSCHECK(gnutls_x509_crt_sign2(cacrt, cacrt, cakey,

               GNUTLS_DIG_SHA256, 0));

  DEBUG(3,("Generating TLS certificate\n"));

  TLSCHECK(gnutls_x509_crt_init(&crt));

  TLSCHECK(gnutls_x509_crt_set_dn_by_oid(crt, 

              GNUTLS_OID_X520_ORGANIZATION_NAME, 0,

              ORGANISATION_NAME, strlen(ORGANISATION_NAME)));

  TLSCHECK(gnutls_x509_crt_set_dn_by_oid(crt, 

              GNUTLS_OID_X520_ORGANIZATIONAL_UNIT_NAME, 0,

              UNIT_NAME, strlen(UNIT_NAME)));

  TLSCHECK(gnutls_x509_crt_set_dn_by_oid(crt,

              GNUTLS_OID_X520_COMMON_NAME, 0,

              hostname, strlen(hostname)));

  TLSCHECK(gnutls_x509_crt_set_subject_alt_name(crt, GNUTLS_SAN_DNSNAME,

                  hostname, strlen(hostname),

                  GNUTLS_FSAN_SET));

  for (adhn_idx = 0;

       additional_hostnames != NULL &&

       additional_hostnames[adhn_idx] != NULL;

       adhn_idx++)

  {

    const char *adhn = additional_hostnames[adhn_idx];

    TLSCHECK(gnutls_x509_crt_set_subject_alt_name(crt, GNUTLS_SAN_DNSNAME,

                    adhn, strlen(adhn),

                    GNUTLS_FSAN_APPEND));

  }

  TLSCHECK(gnutls_x509_crt_set_key(crt, key));

  TLSCHECK(gnutls_x509_crt_set_serial(crt, &serial, sizeof(serial)));

  TLSCHECK(gnutls_x509_crt_set_activation_time(crt, activation));

  TLSCHECK(gnutls_x509_crt_set_expiration_time(crt, expiry));

  TLSCHECK(gnutls_x509_crt_set_ca_status(crt, 0));

  TLSCHECK(gnutls_x509_crt_set_key_purpose_oid(crt, GNUTLS_KP_TLS_WWW_SERVER, 0));

  TLSCHECK(gnutls_x509_crt_set_version(crt, 3));

  TLSCHECK(gnutls_x509_crt_get_key_id(crt, 0, keyid, &keyidsize));

  TLSCHECK(gnutls_x509_crt_set_subject_key_id(crt, keyid, keyidsize));

  TLSCHECK(gnutls_x509_crt_sign2(crt, crt, key,

               GNUTLS_DIG_SHA256, 0));

  TLSCHECK(gnutls_x509_crt_sign2(crt, cacrt, cakey,

               GNUTLS_DIG_SHA256, 0));

  DEBUG(3,("Exporting TLS keys\n"));

  bufsize = sizeof(buf);

  TLSCHECK(gnutls_x509_crt_export(crt, GNUTLS_X509_FMT_PEM, buf, &bufsize));

  if (!file_save(certfile, buf, bufsize)) {

    DEBUG(0,("Unable to save certificate in %s parent dir exists ?\n", certfile));

    goto failed;

  }

  bufsize = sizeof(buf);

  TLSCHECK(gnutls_x509_crt_export(cacrt, GNUTLS_X509_FMT_PEM, buf, &bufsize));

  if (!file_save(cafile, buf, bufsize)) {

    DEBUG(0,("Unable to save ca cert in %s parent dir exists ?\n", cafile));

    goto failed;

  }

  bufsize = sizeof(buf);

  TLSCHECK(gnutls_x509_privkey_export(key, GNUTLS_X509_FMT_PEM, buf, &bufsize));

  if (!file_save_mode(keyfile, buf, bufsize, 0600)) {

    DEBUG(0,("Unable to save privatekey in %s parent dir exists ?\n", keyfile));

    goto failed;

  }

  gnutls_x509_privkey_deinit(key);

  gnutls_x509_privkey_deinit(cakey);

  gnutls_x509_crt_deinit(cacrt);

  gnutls_x509_crt_deinit(crt);

  DEBUG(0,("TLS self-signed keys generated OK\n"));

  return;

failed:

  DEBUG(0,("TLS certificate generation failed\n"));

}