Beispiel #1
0
static CURLcode
mbed_connect_step1(struct connectdata *conn,
                   int sockindex)
{
  struct Curl_easy *data = conn->data;
  struct ssl_connect_data* connssl = &conn->ssl[sockindex];
  const char * const ssl_cafile = SSL_CONN_CONFIG(CAfile);
  const bool verifypeer = SSL_CONN_CONFIG(verifypeer);
  const char * const ssl_capath = SSL_CONN_CONFIG(CApath);
  char * const ssl_cert = SSL_SET_OPTION(cert);
  const char * const ssl_crlfile = SSL_SET_OPTION(CRLfile);
  const char * const hostname = SSL_IS_PROXY() ? conn->http_proxy.host.name :
    conn->host.name;
  const long int port = SSL_IS_PROXY() ? conn->port : conn->remote_port;
  int ret = -1;
  char errorbuf[128];
  errorbuf[0]=0;

  /* mbedTLS only supports SSLv3 and TLSv1 */
  if(SSL_CONN_CONFIG(version) == CURL_SSLVERSION_SSLv2) {
    failf(data, "mbedTLS does not support SSLv2");
    return CURLE_SSL_CONNECT_ERROR;
  }

#ifdef THREADING_SUPPORT
  entropy_init_mutex(&entropy);
  mbedtls_ctr_drbg_init(&connssl->ctr_drbg);

  ret = mbedtls_ctr_drbg_seed(&connssl->ctr_drbg, entropy_func_mutex,
                              &entropy, NULL, 0);
  if(ret) {
#ifdef MBEDTLS_ERROR_C
    mbedtls_strerror(ret, errorbuf, sizeof(errorbuf));
#endif /* MBEDTLS_ERROR_C */
    failf(data, "Failed - mbedTLS: ctr_drbg_init returned (-0x%04X) %s\n",
          -ret, errorbuf);
  }
#else
  mbedtls_entropy_init(&connssl->entropy);
  mbedtls_ctr_drbg_init(&connssl->ctr_drbg);

  ret = mbedtls_ctr_drbg_seed(&connssl->ctr_drbg, mbedtls_entropy_func,
                              &connssl->entropy, NULL, 0);
  if(ret) {
#ifdef MBEDTLS_ERROR_C
    mbedtls_strerror(ret, errorbuf, sizeof(errorbuf));
#endif /* MBEDTLS_ERROR_C */
    failf(data, "Failed - mbedTLS: ctr_drbg_init returned (-0x%04X) %s\n",
          -ret, errorbuf);
  }
#endif /* THREADING_SUPPORT */

  /* Load the trusted CA */
  mbedtls_x509_crt_init(&connssl->cacert);

  if(ssl_cafile) {
    ret = mbedtls_x509_crt_parse_file(&connssl->cacert, ssl_cafile);

    if(ret<0) {
#ifdef MBEDTLS_ERROR_C
      mbedtls_strerror(ret, errorbuf, sizeof(errorbuf));
#endif /* MBEDTLS_ERROR_C */
      failf(data, "Error reading ca cert file %s - mbedTLS: (-0x%04X) %s",
            ssl_cafile, -ret, errorbuf);

      if(verifypeer)
        return CURLE_SSL_CACERT_BADFILE;
    }
  }

  if(ssl_capath) {
    ret = mbedtls_x509_crt_parse_path(&connssl->cacert, ssl_capath);

    if(ret<0) {
#ifdef MBEDTLS_ERROR_C
      mbedtls_strerror(ret, errorbuf, sizeof(errorbuf));
#endif /* MBEDTLS_ERROR_C */
      failf(data, "Error reading ca cert path %s - mbedTLS: (-0x%04X) %s",
            ssl_capath, -ret, errorbuf);

      if(verifypeer)
        return CURLE_SSL_CACERT_BADFILE;
    }
  }

  /* Load the client certificate */
  mbedtls_x509_crt_init(&connssl->clicert);

  if(ssl_cert) {
    ret = mbedtls_x509_crt_parse_file(&connssl->clicert, ssl_cert);

    if(ret) {
#ifdef MBEDTLS_ERROR_C
      mbedtls_strerror(ret, errorbuf, sizeof(errorbuf));
#endif /* MBEDTLS_ERROR_C */
      failf(data, "Error reading client cert file %s - mbedTLS: (-0x%04X) %s",
            ssl_cert, -ret, errorbuf);

      return CURLE_SSL_CERTPROBLEM;
    }
  }

  /* Load the client private key */
  mbedtls_pk_init(&connssl->pk);

  if(SSL_SET_OPTION(key)) {
    ret = mbedtls_pk_parse_keyfile(&connssl->pk, SSL_SET_OPTION(key),
                                   SSL_SET_OPTION(key_passwd));
    if(ret == 0 && !mbedtls_pk_can_do(&connssl->pk, MBEDTLS_PK_RSA))
      ret = MBEDTLS_ERR_PK_TYPE_MISMATCH;

    if(ret) {
#ifdef MBEDTLS_ERROR_C
      mbedtls_strerror(ret, errorbuf, sizeof(errorbuf));
#endif /* MBEDTLS_ERROR_C */
      failf(data, "Error reading private key %s - mbedTLS: (-0x%04X) %s",
            SSL_SET_OPTION(key), -ret, errorbuf);

      return CURLE_SSL_CERTPROBLEM;
    }
  }

  /* Load the CRL */
  mbedtls_x509_crl_init(&connssl->crl);

  if(ssl_crlfile) {
    ret = mbedtls_x509_crl_parse_file(&connssl->crl, ssl_crlfile);

    if(ret) {
#ifdef MBEDTLS_ERROR_C
      mbedtls_strerror(ret, errorbuf, sizeof(errorbuf));
#endif /* MBEDTLS_ERROR_C */
      failf(data, "Error reading CRL file %s - mbedTLS: (-0x%04X) %s",
            ssl_crlfile, -ret, errorbuf);

      return CURLE_SSL_CRL_BADFILE;
    }
  }

  infof(data, "mbedTLS: Connecting to %s:%d\n", hostname, port);

  mbedtls_ssl_config_init(&connssl->config);

  mbedtls_ssl_init(&connssl->ssl);
  if(mbedtls_ssl_setup(&connssl->ssl, &connssl->config)) {
    failf(data, "mbedTLS: ssl_init failed");
    return CURLE_SSL_CONNECT_ERROR;
  }
  ret = mbedtls_ssl_config_defaults(&connssl->config,
                                    MBEDTLS_SSL_IS_CLIENT,
                                    MBEDTLS_SSL_TRANSPORT_STREAM,
                                    MBEDTLS_SSL_PRESET_DEFAULT);
  if(ret) {
    failf(data, "mbedTLS: ssl_config failed");
    return CURLE_SSL_CONNECT_ERROR;
  }

  /* new profile with RSA min key len = 1024 ... */
  mbedtls_ssl_conf_cert_profile(&connssl->config,
                                &mbedtls_x509_crt_profile_fr);

  switch(SSL_CONN_CONFIG(version)) {
  case CURL_SSLVERSION_DEFAULT:
  case CURL_SSLVERSION_TLSv1:
    mbedtls_ssl_conf_min_version(&connssl->config, MBEDTLS_SSL_MAJOR_VERSION_3,
                                 MBEDTLS_SSL_MINOR_VERSION_1);
    infof(data, "mbedTLS: Set min SSL version to TLS 1.0\n");
    break;
  case CURL_SSLVERSION_SSLv3:
    mbedtls_ssl_conf_min_version(&connssl->config, MBEDTLS_SSL_MAJOR_VERSION_3,
                                 MBEDTLS_SSL_MINOR_VERSION_0);
    mbedtls_ssl_conf_max_version(&connssl->config, MBEDTLS_SSL_MAJOR_VERSION_3,
                                 MBEDTLS_SSL_MINOR_VERSION_0);
    infof(data, "mbedTLS: Set SSL version to SSLv3\n");
    break;
  case CURL_SSLVERSION_TLSv1_0:
    mbedtls_ssl_conf_min_version(&connssl->config, MBEDTLS_SSL_MAJOR_VERSION_3,
                                 MBEDTLS_SSL_MINOR_VERSION_1);
    mbedtls_ssl_conf_max_version(&connssl->config, MBEDTLS_SSL_MAJOR_VERSION_3,
                                 MBEDTLS_SSL_MINOR_VERSION_1);
    infof(data, "mbedTLS: Set SSL version to TLS 1.0\n");
    break;
  case CURL_SSLVERSION_TLSv1_1:
    mbedtls_ssl_conf_min_version(&connssl->config, MBEDTLS_SSL_MAJOR_VERSION_3,
                                 MBEDTLS_SSL_MINOR_VERSION_2);
    mbedtls_ssl_conf_max_version(&connssl->config, MBEDTLS_SSL_MAJOR_VERSION_3,
                                 MBEDTLS_SSL_MINOR_VERSION_2);
    infof(data, "mbedTLS: Set SSL version to TLS 1.1\n");
    break;
  case CURL_SSLVERSION_TLSv1_2:
    mbedtls_ssl_conf_min_version(&connssl->config, MBEDTLS_SSL_MAJOR_VERSION_3,
                                 MBEDTLS_SSL_MINOR_VERSION_3);
    mbedtls_ssl_conf_max_version(&connssl->config, MBEDTLS_SSL_MAJOR_VERSION_3,
                                 MBEDTLS_SSL_MINOR_VERSION_3);
    infof(data, "mbedTLS: Set SSL version to TLS 1.2\n");
    break;
  case CURL_SSLVERSION_TLSv1_3:
    failf(data, "mbedTLS: TLS 1.3 is not yet supported");
    return CURLE_SSL_CONNECT_ERROR;
  default:
    failf(data, "Unrecognized parameter passed via CURLOPT_SSLVERSION");
    return CURLE_SSL_CONNECT_ERROR;
  }

  mbedtls_ssl_conf_authmode(&connssl->config, MBEDTLS_SSL_VERIFY_OPTIONAL);

  mbedtls_ssl_conf_rng(&connssl->config, mbedtls_ctr_drbg_random,
                       &connssl->ctr_drbg);
  mbedtls_ssl_set_bio(&connssl->ssl, &conn->sock[sockindex],
                      mbedtls_net_send,
                      mbedtls_net_recv,
                      NULL /*  rev_timeout() */);

  mbedtls_ssl_conf_ciphersuites(&connssl->config,
                                mbedtls_ssl_list_ciphersuites());

#if defined(MBEDTLS_SSL_SESSION_TICKETS)
  mbedtls_ssl_conf_session_tickets(&connssl->config,
                                   MBEDTLS_SSL_SESSION_TICKETS_DISABLED);
#endif

  /* Check if there's a cached ID we can/should use here! */
  if(data->set.general_ssl.sessionid) {
    void *old_session = NULL;

    Curl_ssl_sessionid_lock(conn);
    if(!Curl_ssl_getsessionid(conn, &old_session, NULL, sockindex)) {
      ret = mbedtls_ssl_set_session(&connssl->ssl, old_session);
      if(ret) {
        Curl_ssl_sessionid_unlock(conn);
        failf(data, "mbedtls_ssl_set_session returned -0x%x", -ret);
        return CURLE_SSL_CONNECT_ERROR;
      }
      infof(data, "mbedTLS re-using session\n");
    }
    Curl_ssl_sessionid_unlock(conn);
  }

  mbedtls_ssl_conf_ca_chain(&connssl->config,
                            &connssl->cacert,
                            &connssl->crl);

  if(SSL_SET_OPTION(key)) {
    mbedtls_ssl_conf_own_cert(&connssl->config,
                              &connssl->clicert, &connssl->pk);
  }
  if(mbedtls_ssl_set_hostname(&connssl->ssl, hostname)) {
    /* mbedtls_ssl_set_hostname() sets the name to use in CN/SAN checks *and*
       the name to set in the SNI extension. So even if curl connects to a
       host specified as an IP address, this function must be used. */
    failf(data, "couldn't set hostname in mbedTLS");
    return CURLE_SSL_CONNECT_ERROR;
  }

#ifdef HAS_ALPN
  if(conn->bits.tls_enable_alpn) {
    const char **p = &connssl->protocols[0];
#ifdef USE_NGHTTP2
    if(data->set.httpversion >= CURL_HTTP_VERSION_2)
      *p++ = NGHTTP2_PROTO_VERSION_ID;
#endif
    *p++ = ALPN_HTTP_1_1;
    *p = NULL;
    /* this function doesn't clone the protocols array, which is why we need
       to keep it around */
    if(mbedtls_ssl_conf_alpn_protocols(&connssl->config,
                                       &connssl->protocols[0])) {
      failf(data, "Failed setting ALPN protocols");
      return CURLE_SSL_CONNECT_ERROR;
    }
    for(p = &connssl->protocols[0]; *p; ++p)
      infof(data, "ALPN, offering %s\n", *p);
  }
#endif

#ifdef MBEDTLS_DEBUG
  /* In order to make that work in mbedtls MBEDTLS_DEBUG_C must be defined. */
  mbedtls_ssl_conf_dbg(&connssl->config, mbed_debug, data);
  /* - 0 No debug
   * - 1 Error
   * - 2 State change
   * - 3 Informational
   * - 4 Verbose
   */
  mbedtls_debug_set_threshold(4);
#endif

  connssl->connecting_state = ssl_connect_2;

  return CURLE_OK;
}
Beispiel #2
0
static CURLcode
mbedtls_connect_step1(struct connectdata *conn,
                      int sockindex)
{
  struct SessionHandle *data = conn->data;
  struct ssl_connect_data* connssl = &conn->ssl[sockindex];

  bool sni = TRUE; /* default is SNI enabled */
  int ret = -1;
#ifdef ENABLE_IPV6
  struct in6_addr addr;
#else
  struct in_addr addr;
#endif
  void *old_session = NULL;
  size_t old_session_size = 0;
  char errorbuf[128];
  errorbuf[0]=0;

  /* mbedTLS only supports SSLv3 and TLSv1 */
  if(data->set.ssl.version == CURL_SSLVERSION_SSLv2) {
    failf(data, "mbedTLS does not support SSLv2");
    return CURLE_SSL_CONNECT_ERROR;
  }
  else if(data->set.ssl.version == CURL_SSLVERSION_SSLv3)
    sni = FALSE; /* SSLv3 has no SNI */

#ifdef THREADING_SUPPORT
  entropy_init_mutex(&entropy);
  mbedtls_ctr_drbg_init(&connssl->ctr_drbg);

  ret = mbedtls_ctr_drbg_seed(&connssl->ctr_drbg, entropy_func_mutex,
                              &entropy, connssl->ssn.id,
                              connssl->ssn.id_len);
  if(ret) {
#ifdef MBEDTLS_ERROR_C
    mbedtls_strerror(ret, errorbuf, sizeof(errorbuf));
#endif /* MBEDTLS_ERROR_C */
    failf(data, "Failed - mbedTLS: ctr_drbg_init returned (-0x%04X) %s\n",
          -ret, errorbuf);
  }
#else
  mbedtls_entropy_init(&connssl->entropy);
  mbedtls_ctr_drbg_init(&connssl->ctr_drbg);

  ret = mbedtls_ctr_drbg_seed(&connssl->ctr_drbg, mbedtls_entropy_func,
                              &connssl->entropy, connssl->ssn.id,
                              connssl->ssn.id_len);
  if(ret) {
#ifdef MBEDTLS_ERROR_C
    mbedtls_strerror(ret, errorbuf, sizeof(errorbuf));
#endif /* MBEDTLS_ERROR_C */
    failf(data, "Failed - mbedTLS: ctr_drbg_init returned (-0x%04X) %s\n",
          -ret, errorbuf);
  }
#endif /* THREADING_SUPPORT */

  /* Load the trusted CA */
  mbedtls_x509_crt_init(&connssl->cacert);

  if(data->set.str[STRING_SSL_CAFILE]) {
    ret = mbedtls_x509_crt_parse_file(&connssl->cacert,
                                      data->set.str[STRING_SSL_CAFILE]);

    if(ret<0) {
#ifdef MBEDTLS_ERROR_C
      mbedtls_strerror(ret, errorbuf, sizeof(errorbuf));
#endif /* MBEDTLS_ERROR_C */
      failf(data, "Error reading ca cert file %s - mbedTLS: (-0x%04X) %s",
            data->set.str[STRING_SSL_CAFILE], -ret, errorbuf);

      if(data->set.ssl.verifypeer)
        return CURLE_SSL_CACERT_BADFILE;
    }
  }

  if(data->set.str[STRING_SSL_CAPATH]) {
    ret = mbedtls_x509_crt_parse_path(&connssl->cacert,
                                      data->set.str[STRING_SSL_CAPATH]);

    if(ret<0) {
#ifdef MBEDTLS_ERROR_C
      mbedtls_strerror(ret, errorbuf, sizeof(errorbuf));
#endif /* MBEDTLS_ERROR_C */
      failf(data, "Error reading ca cert path %s - mbedTLS: (-0x%04X) %s",
            data->set.str[STRING_SSL_CAPATH], -ret, errorbuf);

      if(data->set.ssl.verifypeer)
        return CURLE_SSL_CACERT_BADFILE;
    }
  }

  /* Load the client certificate */
  mbedtls_x509_crt_init(&connssl->clicert);

  if(data->set.str[STRING_CERT]) {
    ret = mbedtls_x509_crt_parse_file(&connssl->clicert,
                                      data->set.str[STRING_CERT]);

    if(ret) {
#ifdef MBEDTLS_ERROR_C
      mbedtls_strerror(ret, errorbuf, sizeof(errorbuf));
#endif /* MBEDTLS_ERROR_C */
      failf(data, "Error reading client cert file %s - mbedTLS: (-0x%04X) %s",
            data->set.str[STRING_CERT], -ret, errorbuf);

      return CURLE_SSL_CERTPROBLEM;
    }
  }

  /* Load the client private key */
  mbedtls_pk_init(&connssl->pk);

  if(data->set.str[STRING_KEY]) {
    ret = mbedtls_pk_parse_keyfile(&connssl->pk, data->set.str[STRING_KEY],
                                   data->set.str[STRING_KEY_PASSWD]);
    if(ret == 0 && !mbedtls_pk_can_do(&connssl->pk, MBEDTLS_PK_RSA))
      ret = MBEDTLS_ERR_PK_TYPE_MISMATCH;

    if(ret) {
#ifdef MBEDTLS_ERROR_C
      mbedtls_strerror(ret, errorbuf, sizeof(errorbuf));
#endif /* MBEDTLS_ERROR_C */
      failf(data, "Error reading private key %s - mbedTLS: (-0x%04X) %s",
            data->set.str[STRING_KEY], -ret, errorbuf);

      return CURLE_SSL_CERTPROBLEM;
    }
  }

  /* Load the CRL */
  mbedtls_x509_crl_init(&connssl->crl);

  if(data->set.str[STRING_SSL_CRLFILE]) {
    ret = mbedtls_x509_crl_parse_file(&connssl->crl,
                                      data->set.str[STRING_SSL_CRLFILE]);

    if(ret) {
#ifdef MBEDTLS_ERROR_C
      mbedtls_strerror(ret, errorbuf, sizeof(errorbuf));
#endif /* MBEDTLS_ERROR_C */
      failf(data, "Error reading CRL file %s - mbedTLS: (-0x%04X) %s",
            data->set.str[STRING_SSL_CRLFILE], -ret, errorbuf);

      return CURLE_SSL_CRL_BADFILE;
    }
  }

  infof(data, "mbedTLS: Connecting to %s:%d\n",
        conn->host.name, conn->remote_port);

  mbedtls_ssl_config_init(&connssl->config);

  mbedtls_ssl_init(&connssl->ssl);
  if(mbedtls_ssl_setup(&connssl->ssl, &connssl->config)) {
    failf(data, "mbedTLS: ssl_init failed");
    return CURLE_SSL_CONNECT_ERROR;
  }
  ret = mbedtls_ssl_config_defaults(&connssl->config,
                                    MBEDTLS_SSL_IS_CLIENT,
                                    MBEDTLS_SSL_TRANSPORT_STREAM,
                                    MBEDTLS_SSL_PRESET_DEFAULT);
  if(ret) {
    failf(data, "mbedTLS: ssl_config failed");
    return CURLE_SSL_CONNECT_ERROR;
  }

  /* new profile with RSA min key len = 1024 ... */
  mbedtls_ssl_conf_cert_profile( &connssl->config,
                                 &mbedtls_x509_crt_profile_fr);

  switch(data->set.ssl.version) {
  case CURL_SSLVERSION_SSLv3:
    mbedtls_ssl_conf_min_version(&connssl->config, MBEDTLS_SSL_MAJOR_VERSION_3,
                                 MBEDTLS_SSL_MINOR_VERSION_0);
    infof(data, "mbedTLS: Forced min. SSL Version to be SSLv3\n");
    break;
  case CURL_SSLVERSION_TLSv1_0:
    mbedtls_ssl_conf_min_version(&connssl->config, MBEDTLS_SSL_MAJOR_VERSION_3,
                                 MBEDTLS_SSL_MINOR_VERSION_1);
    infof(data, "mbedTLS: Forced min. SSL Version to be TLS 1.0\n");
    break;
  case CURL_SSLVERSION_TLSv1_1:
    mbedtls_ssl_conf_min_version(&connssl->config, MBEDTLS_SSL_MAJOR_VERSION_3,
                                 MBEDTLS_SSL_MINOR_VERSION_2);
    infof(data, "mbedTLS: Forced min. SSL Version to be TLS 1.1\n");
    break;
  case CURL_SSLVERSION_TLSv1_2:
    mbedtls_ssl_conf_min_version(&connssl->config, MBEDTLS_SSL_MAJOR_VERSION_3,
                                 MBEDTLS_SSL_MINOR_VERSION_3);
    infof(data, "mbedTLS: Forced min. SSL Version to be TLS 1.2\n");
    break;
  }

  mbedtls_ssl_conf_authmode(&connssl->config, MBEDTLS_SSL_VERIFY_OPTIONAL);

  mbedtls_ssl_conf_rng(&connssl->config, mbedtls_ctr_drbg_random,
                       &connssl->ctr_drbg);
  mbedtls_ssl_set_bio(&connssl->ssl, &conn->sock[sockindex],
                      mbedtls_net_send,
                      mbedtls_net_recv,
                      NULL /*  rev_timeout() */);

  mbedtls_ssl_conf_ciphersuites(&connssl->config,
                                mbedtls_ssl_list_ciphersuites());
  if(!Curl_ssl_getsessionid(conn, &old_session, &old_session_size)) {
    memcpy(&connssl->ssn, old_session, old_session_size);
    infof(data, "mbedTLS re-using session\n");
  }

  mbedtls_ssl_set_session(&connssl->ssl,
                          &connssl->ssn);

  mbedtls_ssl_conf_ca_chain(&connssl->config,
                            &connssl->cacert,
                            &connssl->crl);

  if(data->set.str[STRING_KEY]) {
    mbedtls_ssl_conf_own_cert(&connssl->config,
                              &connssl->clicert, &connssl->pk);
  }
  if(!Curl_inet_pton(AF_INET, conn->host.name, &addr) &&
#ifdef ENABLE_IPV6
     !Curl_inet_pton(AF_INET6, conn->host.name, &addr) &&
#endif
     sni && mbedtls_ssl_set_hostname(&connssl->ssl, conn->host.name)) {
    infof(data, "WARNING: failed to configure "
          "server name indication (SNI) TLS extension\n");
  }

#ifdef HAS_ALPN
  if(data->set.ssl_enable_alpn) {
    const char **p = &connssl->protocols[0];
#ifdef USE_NGHTTP2
    if(data->set.httpversion >= CURL_HTTP_VERSION_2)
      *p++ = NGHTTP2_PROTO_VERSION_ID;
#endif
    *p++ = ALPN_HTTP_1_1;
    *p = NULL;
    /* this function doesn't clone the protocols array, which is why we need
       to keep it around */
    if(mbedtls_ssl_conf_alpn_protocols(&connssl->config,
                                       &connssl->protocols[0])) {
      failf(data, "Failed setting ALPN protocols");
      return CURLE_SSL_CONNECT_ERROR;
    }
    for(p = &connssl->protocols[0]; *p; ++p)
      infof(data, "ALPN, offering %s\n", *p);
  }
#endif

#ifdef MBEDTLS_DEBUG
  mbedtls_ssl_conf_dbg(&connssl->ssl, mbedtls_debug, data);
#endif

  connssl->connecting_state = ssl_connect_2;

  return CURLE_OK;
}
Beispiel #3
0
static CURLcode
mbed_connect_step1(struct connectdata *conn,
                   int sockindex)
{
  struct SessionHandle *data = conn->data;
  struct ssl_connect_data* connssl = &conn->ssl[sockindex];

  int ret = -1;
  void *old_session = NULL;
  char errorbuf[128];
  errorbuf[0]=0;

  /* mbedTLS only supports SSLv3 and TLSv1 */
  if(data->set.ssl.version == CURL_SSLVERSION_SSLv2) {
    failf(data, "mbedTLS does not support SSLv2");
    return CURLE_SSL_CONNECT_ERROR;
  }

#ifdef THREADING_SUPPORT
  entropy_init_mutex(&entropy);
  mbedtls_ctr_drbg_init(&connssl->ctr_drbg);

  ret = mbedtls_ctr_drbg_seed(&connssl->ctr_drbg, entropy_func_mutex,
                              &entropy, NULL, 0);
  if(ret) {
#ifdef MBEDTLS_ERROR_C
    mbedtls_strerror(ret, errorbuf, sizeof(errorbuf));
#endif /* MBEDTLS_ERROR_C */
    failf(data, "Failed - mbedTLS: ctr_drbg_init returned (-0x%04X) %s\n",
          -ret, errorbuf);
  }
#else
  mbedtls_entropy_init(&connssl->entropy);
  mbedtls_ctr_drbg_init(&connssl->ctr_drbg);

  ret = mbedtls_ctr_drbg_seed(&connssl->ctr_drbg, mbedtls_entropy_func,
                              &connssl->entropy, NULL, 0);
  if(ret) {
#ifdef MBEDTLS_ERROR_C
    mbedtls_strerror(ret, errorbuf, sizeof(errorbuf));
#endif /* MBEDTLS_ERROR_C */
    failf(data, "Failed - mbedTLS: ctr_drbg_init returned (-0x%04X) %s\n",
          -ret, errorbuf);
  }
#endif /* THREADING_SUPPORT */

  /* Load the trusted CA */
  mbedtls_x509_crt_init(&connssl->cacert);

  if(data->set.str[STRING_SSL_CAFILE]) {
    ret = mbedtls_x509_crt_parse_file(&connssl->cacert,
                                      data->set.str[STRING_SSL_CAFILE]);

    if(ret<0) {
#ifdef MBEDTLS_ERROR_C
      mbedtls_strerror(ret, errorbuf, sizeof(errorbuf));
#endif /* MBEDTLS_ERROR_C */
      failf(data, "Error reading ca cert file %s - mbedTLS: (-0x%04X) %s",
            data->set.str[STRING_SSL_CAFILE], -ret, errorbuf);

      if(data->set.ssl.verifypeer)
        return CURLE_SSL_CACERT_BADFILE;
    }
  }

  if(data->set.str[STRING_SSL_CAPATH]) {
    ret = mbedtls_x509_crt_parse_path(&connssl->cacert,
                                      data->set.str[STRING_SSL_CAPATH]);

    if(ret<0) {
#ifdef MBEDTLS_ERROR_C
      mbedtls_strerror(ret, errorbuf, sizeof(errorbuf));
#endif /* MBEDTLS_ERROR_C */
      failf(data, "Error reading ca cert path %s - mbedTLS: (-0x%04X) %s",
            data->set.str[STRING_SSL_CAPATH], -ret, errorbuf);

      if(data->set.ssl.verifypeer)
        return CURLE_SSL_CACERT_BADFILE;
    }
  }

  /* Load the client certificate */
  mbedtls_x509_crt_init(&connssl->clicert);

  if(data->set.str[STRING_CERT]) {
    ret = mbedtls_x509_crt_parse_file(&connssl->clicert,
                                      data->set.str[STRING_CERT]);

    if(ret) {
#ifdef MBEDTLS_ERROR_C
      mbedtls_strerror(ret, errorbuf, sizeof(errorbuf));
#endif /* MBEDTLS_ERROR_C */
      failf(data, "Error reading client cert file %s - mbedTLS: (-0x%04X) %s",
            data->set.str[STRING_CERT], -ret, errorbuf);

      return CURLE_SSL_CERTPROBLEM;
    }
  }

  /* Load the client private key */
  mbedtls_pk_init(&connssl->pk);

  if(data->set.str[STRING_KEY]) {
    ret = mbedtls_pk_parse_keyfile(&connssl->pk, data->set.str[STRING_KEY],
                                   data->set.str[STRING_KEY_PASSWD]);
    if(ret == 0 && !mbedtls_pk_can_do(&connssl->pk, MBEDTLS_PK_RSA))
      ret = MBEDTLS_ERR_PK_TYPE_MISMATCH;

    if(ret) {
#ifdef MBEDTLS_ERROR_C
      mbedtls_strerror(ret, errorbuf, sizeof(errorbuf));
#endif /* MBEDTLS_ERROR_C */
      failf(data, "Error reading private key %s - mbedTLS: (-0x%04X) %s",
            data->set.str[STRING_KEY], -ret, errorbuf);

      return CURLE_SSL_CERTPROBLEM;
    }
  }

  /* Load the CRL */
  mbedtls_x509_crl_init(&connssl->crl);

  if(data->set.str[STRING_SSL_CRLFILE]) {
    ret = mbedtls_x509_crl_parse_file(&connssl->crl,
                                      data->set.str[STRING_SSL_CRLFILE]);

    if(ret) {
#ifdef MBEDTLS_ERROR_C
      mbedtls_strerror(ret, errorbuf, sizeof(errorbuf));
#endif /* MBEDTLS_ERROR_C */
      failf(data, "Error reading CRL file %s - mbedTLS: (-0x%04X) %s",
            data->set.str[STRING_SSL_CRLFILE], -ret, errorbuf);

      return CURLE_SSL_CRL_BADFILE;
    }
  }

  infof(data, "mbedTLS: Connecting to %s:%d\n",
        conn->host.name, conn->remote_port);

  mbedtls_ssl_config_init(&connssl->config);

  mbedtls_ssl_init(&connssl->ssl);
  if(mbedtls_ssl_setup(&connssl->ssl, &connssl->config)) {
    failf(data, "mbedTLS: ssl_init failed");
    return CURLE_SSL_CONNECT_ERROR;
  }
  ret = mbedtls_ssl_config_defaults(&connssl->config,
                                    MBEDTLS_SSL_IS_CLIENT,
                                    MBEDTLS_SSL_TRANSPORT_STREAM,
                                    MBEDTLS_SSL_PRESET_DEFAULT);
  if(ret) {
    failf(data, "mbedTLS: ssl_config failed");
    return CURLE_SSL_CONNECT_ERROR;
  }

  /* new profile with RSA min key len = 1024 ... */
  mbedtls_ssl_conf_cert_profile(&connssl->config,
                                &mbedtls_x509_crt_profile_fr);

  switch(data->set.ssl.version) {
  case CURL_SSLVERSION_DEFAULT:
  case CURL_SSLVERSION_TLSv1:
    mbedtls_ssl_conf_min_version(&connssl->config, MBEDTLS_SSL_MAJOR_VERSION_3,
                                 MBEDTLS_SSL_MINOR_VERSION_1);
    infof(data, "mbedTLS: Set min SSL version to TLS 1.0\n");
    break;
  case CURL_SSLVERSION_SSLv3:
    mbedtls_ssl_conf_min_version(&connssl->config, MBEDTLS_SSL_MAJOR_VERSION_3,
                                 MBEDTLS_SSL_MINOR_VERSION_0);
    mbedtls_ssl_conf_max_version(&connssl->config, MBEDTLS_SSL_MAJOR_VERSION_3,
                                 MBEDTLS_SSL_MINOR_VERSION_0);
    infof(data, "mbedTLS: Set SSL version to SSLv3\n");
    break;
  case CURL_SSLVERSION_TLSv1_0:
    mbedtls_ssl_conf_min_version(&connssl->config, MBEDTLS_SSL_MAJOR_VERSION_3,
                                 MBEDTLS_SSL_MINOR_VERSION_1);
    mbedtls_ssl_conf_max_version(&connssl->config, MBEDTLS_SSL_MAJOR_VERSION_3,
                                 MBEDTLS_SSL_MINOR_VERSION_1);
    infof(data, "mbedTLS: Set SSL version to TLS 1.0\n");
    break;
  case CURL_SSLVERSION_TLSv1_1:
    mbedtls_ssl_conf_min_version(&connssl->config, MBEDTLS_SSL_MAJOR_VERSION_3,
                                 MBEDTLS_SSL_MINOR_VERSION_2);
    mbedtls_ssl_conf_max_version(&connssl->config, MBEDTLS_SSL_MAJOR_VERSION_3,
                                 MBEDTLS_SSL_MINOR_VERSION_2);
    infof(data, "mbedTLS: Set SSL version to TLS 1.1\n");
    break;
  case CURL_SSLVERSION_TLSv1_2:
    mbedtls_ssl_conf_min_version(&connssl->config, MBEDTLS_SSL_MAJOR_VERSION_3,
                                 MBEDTLS_SSL_MINOR_VERSION_3);
    mbedtls_ssl_conf_max_version(&connssl->config, MBEDTLS_SSL_MAJOR_VERSION_3,
                                 MBEDTLS_SSL_MINOR_VERSION_3);
    infof(data, "mbedTLS: Set SSL version to TLS 1.2\n");
    break;
  default:
    failf(data, "mbedTLS: Unsupported SSL protocol version");
    return CURLE_SSL_CONNECT_ERROR;
  }

  mbedtls_ssl_conf_authmode(&connssl->config, MBEDTLS_SSL_VERIFY_OPTIONAL);

  mbedtls_ssl_conf_rng(&connssl->config, mbedtls_ctr_drbg_random,
                       &connssl->ctr_drbg);
  mbedtls_ssl_set_bio(&connssl->ssl, &conn->sock[sockindex],
                      mbedtls_net_send,
                      mbedtls_net_recv,
                      NULL /*  rev_timeout() */);

  mbedtls_ssl_conf_ciphersuites(&connssl->config,
                                mbedtls_ssl_list_ciphersuites());
  if(!Curl_ssl_getsessionid(conn, &old_session, NULL)) {
    ret = mbedtls_ssl_set_session(&connssl->ssl, old_session);
    if(ret) {
      failf(data, "mbedtls_ssl_set_session returned -0x%x", -ret);
      return CURLE_SSL_CONNECT_ERROR;
    }
    infof(data, "mbedTLS re-using session\n");
  }

  mbedtls_ssl_conf_ca_chain(&connssl->config,
                            &connssl->cacert,
                            &connssl->crl);

  if(data->set.str[STRING_KEY]) {
    mbedtls_ssl_conf_own_cert(&connssl->config,
                              &connssl->clicert, &connssl->pk);
  }
  if(mbedtls_ssl_set_hostname(&connssl->ssl, conn->host.name)) {
    /* mbedtls_ssl_set_hostname() sets the name to use in CN/SAN checks *and*
       the name to set in the SNI extension. So even if curl connects to a
       host specified as an IP address, this function must be used. */
    failf(data, "couldn't set hostname in mbedTLS");
    return CURLE_SSL_CONNECT_ERROR;
  }

#ifdef HAS_ALPN
  if(conn->bits.tls_enable_alpn) {
    const char **p = &connssl->protocols[0];
#ifdef USE_NGHTTP2
    if(data->set.httpversion >= CURL_HTTP_VERSION_2)
      *p++ = NGHTTP2_PROTO_VERSION_ID;
#endif
    *p++ = ALPN_HTTP_1_1;
    *p = NULL;
    /* this function doesn't clone the protocols array, which is why we need
       to keep it around */
    if(mbedtls_ssl_conf_alpn_protocols(&connssl->config,
                                       &connssl->protocols[0])) {
      failf(data, "Failed setting ALPN protocols");
      return CURLE_SSL_CONNECT_ERROR;
    }
    for(p = &connssl->protocols[0]; *p; ++p)
      infof(data, "ALPN, offering %s\n", *p);
  }
#endif

#ifdef MBEDTLS_DEBUG
  mbedtls_ssl_conf_dbg(&connssl->config, mbedtls_debug, data);
#endif

  connssl->connecting_state = ssl_connect_2;

  return CURLE_OK;
}
Beispiel #4
0
int main( int argc, char *argv[] )
{
    int ret = 1, len;
    int exit_code = MBEDTLS_EXIT_FAILURE;
    mbedtls_net_context server_fd;
    unsigned char buf[1024];
#if defined(MBEDTLS_BASE64_C)
    unsigned char base[1024];
#endif
    char hostname[32];
    const char *pers = "ssl_mail_client";

    mbedtls_entropy_context entropy;
    mbedtls_ctr_drbg_context ctr_drbg;
    mbedtls_ssl_context ssl;
    mbedtls_ssl_config conf;
    mbedtls_x509_crt cacert;
    mbedtls_x509_crt clicert;
    mbedtls_pk_context pkey;
    int i;
    size_t n;
    char *p, *q;
    const int *list;

    /*
     * Make sure memory references are valid in case we exit early.
     */
    mbedtls_net_init( &server_fd );
    mbedtls_ssl_init( &ssl );
    mbedtls_ssl_config_init( &conf );
    memset( &buf, 0, sizeof( buf ) );
    mbedtls_x509_crt_init( &cacert );
    mbedtls_x509_crt_init( &clicert );
    mbedtls_pk_init( &pkey );
    mbedtls_ctr_drbg_init( &ctr_drbg );

    if( argc == 0 )
    {
    usage:
        mbedtls_printf( USAGE );

        list = mbedtls_ssl_list_ciphersuites();
        while( *list )
        {
            mbedtls_printf("    %s\n", mbedtls_ssl_get_ciphersuite_name( *list ) );
            list++;
        }
        mbedtls_printf("\n");
        goto exit;
    }

    opt.server_name         = DFL_SERVER_NAME;
    opt.server_port         = DFL_SERVER_PORT;
    opt.debug_level         = DFL_DEBUG_LEVEL;
    opt.authentication      = DFL_AUTHENTICATION;
    opt.mode                = DFL_MODE;
    opt.user_name           = DFL_USER_NAME;
    opt.user_pwd            = DFL_USER_PWD;
    opt.mail_from           = DFL_MAIL_FROM;
    opt.mail_to             = DFL_MAIL_TO;
    opt.ca_file             = DFL_CA_FILE;
    opt.crt_file            = DFL_CRT_FILE;
    opt.key_file            = DFL_KEY_FILE;
    opt.force_ciphersuite[0]= DFL_FORCE_CIPHER;

    for( i = 1; i < argc; i++ )
    {
        p = argv[i];
        if( ( q = strchr( p, '=' ) ) == NULL )
            goto usage;
        *q++ = '\0';

        if( strcmp( p, "server_name" ) == 0 )
            opt.server_name = q;
        else if( strcmp( p, "server_port" ) == 0 )
            opt.server_port = q;
        else if( strcmp( p, "debug_level" ) == 0 )
        {
            opt.debug_level = atoi( q );
            if( opt.debug_level < 0 || opt.debug_level > 65535 )
                goto usage;
        }
        else if( strcmp( p, "authentication" ) == 0 )
        {
            opt.authentication = atoi( q );
            if( opt.authentication < 0 || opt.authentication > 1 )
                goto usage;
        }
        else if( strcmp( p, "mode" ) == 0 )
        {
            opt.mode = atoi( q );
            if( opt.mode < 0 || opt.mode > 1 )
                goto usage;
        }
        else if( strcmp( p, "user_name" ) == 0 )
            opt.user_name = q;
        else if( strcmp( p, "user_pwd" ) == 0 )
            opt.user_pwd = q;
        else if( strcmp( p, "mail_from" ) == 0 )
            opt.mail_from = q;
        else if( strcmp( p, "mail_to" ) == 0 )
            opt.mail_to = q;
        else if( strcmp( p, "ca_file" ) == 0 )
            opt.ca_file = q;
        else if( strcmp( p, "crt_file" ) == 0 )
            opt.crt_file = q;
        else if( strcmp( p, "key_file" ) == 0 )
            opt.key_file = q;
        else if( strcmp( p, "force_ciphersuite" ) == 0 )
        {
            opt.force_ciphersuite[0] = -1;

            opt.force_ciphersuite[0] = mbedtls_ssl_get_ciphersuite_id( q );

            if( opt.force_ciphersuite[0] <= 0 )
                goto usage;

            opt.force_ciphersuite[1] = 0;
        }
        else
            goto usage;
    }

    /*
     * 0. Initialize the RNG and the session data
     */
    mbedtls_printf( "\n  . Seeding the random number generator..." );
    fflush( stdout );

    mbedtls_entropy_init( &entropy );
    if( ( ret = mbedtls_ctr_drbg_seed( &ctr_drbg, mbedtls_entropy_func, &entropy,
                               (const unsigned char *) pers,
                               strlen( pers ) ) ) != 0 )
    {
        mbedtls_printf( " failed\n  ! mbedtls_ctr_drbg_seed returned %d\n", ret );
        goto exit;
    }

    mbedtls_printf( " ok\n" );

    /*
     * 1.1. Load the trusted CA
     */
    mbedtls_printf( "  . Loading the CA root certificate ..." );
    fflush( stdout );

#if defined(MBEDTLS_FS_IO)
    if( strlen( opt.ca_file ) )
        ret = mbedtls_x509_crt_parse_file( &cacert, opt.ca_file );
    else
#endif
#if defined(MBEDTLS_CERTS_C) && defined(MBEDTLS_PEM_PARSE_C)
        ret = mbedtls_x509_crt_parse( &cacert, (const unsigned char *) mbedtls_test_cas_pem,
                              mbedtls_test_cas_pem_len );
#else
    {
        mbedtls_printf("MBEDTLS_CERTS_C and/or MBEDTLS_PEM_PARSE_C not defined.");
        goto exit;
    }
#endif
    if( ret < 0 )
    {
        mbedtls_printf( " failed\n  !  mbedtls_x509_crt_parse returned %d\n\n", ret );
        goto exit;
    }

    mbedtls_printf( " ok (%d skipped)\n", ret );

    /*
     * 1.2. Load own certificate and private key
     *
     * (can be skipped if client authentication is not required)
     */
    mbedtls_printf( "  . Loading the client cert. and key..." );
    fflush( stdout );

#if defined(MBEDTLS_FS_IO)
    if( strlen( opt.crt_file ) )
        ret = mbedtls_x509_crt_parse_file( &clicert, opt.crt_file );
    else
#endif
#if defined(MBEDTLS_CERTS_C)
        ret = mbedtls_x509_crt_parse( &clicert, (const unsigned char *) mbedtls_test_cli_crt,
                              mbedtls_test_cli_crt_len );
#else
    {
        mbedtls_printf("MBEDTLS_CERTS_C not defined.");
        goto exit;
    }
#endif
    if( ret != 0 )
    {
        mbedtls_printf( " failed\n  !  mbedtls_x509_crt_parse returned %d\n\n", ret );
        goto exit;
    }

#if defined(MBEDTLS_FS_IO)
    if( strlen( opt.key_file ) )
        ret = mbedtls_pk_parse_keyfile( &pkey, opt.key_file, "" );
    else
#endif
#if defined(MBEDTLS_CERTS_C) && defined(MBEDTLS_PEM_PARSE_C)
        ret = mbedtls_pk_parse_key( &pkey, (const unsigned char *) mbedtls_test_cli_key,
                mbedtls_test_cli_key_len, NULL, 0 );
#else
    {
        mbedtls_printf("MBEDTLS_CERTS_C or MBEDTLS_PEM_PARSE_C not defined.");
        goto exit;
    }
#endif
    if( ret != 0 )
    {
        mbedtls_printf( " failed\n  !  mbedtls_pk_parse_key returned %d\n\n", ret );
        goto exit;
    }

    mbedtls_printf( " ok\n" );

    /*
     * 2. Start the connection
     */
    mbedtls_printf( "  . Connecting to tcp/%s/%s...", opt.server_name,
                                                opt.server_port );
    fflush( stdout );

    if( ( ret = mbedtls_net_connect( &server_fd, opt.server_name,
                             opt.server_port, MBEDTLS_NET_PROTO_TCP ) ) != 0 )
    {
        mbedtls_printf( " failed\n  ! mbedtls_net_connect returned %d\n\n", ret );
        goto exit;
    }

    mbedtls_printf( " ok\n" );

    /*
     * 3. Setup stuff
     */
    mbedtls_printf( "  . Setting up the SSL/TLS structure..." );
    fflush( stdout );

    if( ( ret = mbedtls_ssl_config_defaults( &conf,
                    MBEDTLS_SSL_IS_CLIENT,
                    MBEDTLS_SSL_TRANSPORT_STREAM,
                    MBEDTLS_SSL_PRESET_DEFAULT ) ) != 0 )
    {
        mbedtls_printf( " failed\n  ! mbedtls_ssl_config_defaults returned %d\n\n", ret );
        goto exit;
    }

    /* OPTIONAL is not optimal for security,
     * but makes interop easier in this simplified example */
    mbedtls_ssl_conf_authmode( &conf, MBEDTLS_SSL_VERIFY_OPTIONAL );

    mbedtls_ssl_conf_rng( &conf, mbedtls_ctr_drbg_random, &ctr_drbg );
    mbedtls_ssl_conf_dbg( &conf, my_debug, stdout );

    if( opt.force_ciphersuite[0] != DFL_FORCE_CIPHER )
        mbedtls_ssl_conf_ciphersuites( &conf, opt.force_ciphersuite );

    mbedtls_ssl_conf_ca_chain( &conf, &cacert, NULL );
    if( ( ret = mbedtls_ssl_conf_own_cert( &conf, &clicert, &pkey ) ) != 0 )
    {
        mbedtls_printf( " failed\n  ! mbedtls_ssl_conf_own_cert returned %d\n\n", ret );
        goto exit;
    }

    if( ( ret = mbedtls_ssl_setup( &ssl, &conf ) ) != 0 )
    {
        mbedtls_printf( " failed\n  ! mbedtls_ssl_setup returned %d\n\n", ret );
        goto exit;
    }

    if( ( ret = mbedtls_ssl_set_hostname( &ssl, opt.server_name ) ) != 0 )
    {
        mbedtls_printf( " failed\n  ! mbedtls_ssl_set_hostname returned %d\n\n", ret );
        goto exit;
    }

    mbedtls_ssl_set_bio( &ssl, &server_fd, mbedtls_net_send, mbedtls_net_recv, NULL );

    mbedtls_printf( " ok\n" );

    if( opt.mode == MODE_SSL_TLS )
    {
        if( do_handshake( &ssl ) != 0 )
            goto exit;

        mbedtls_printf( "  > Get header from server:" );
        fflush( stdout );

        ret = write_ssl_and_get_response( &ssl, buf, 0 );
        if( ret < 200 || ret > 299 )
        {
            mbedtls_printf( " failed\n  ! server responded with %d\n\n", ret );
            goto exit;
        }

        mbedtls_printf(" ok\n" );

        mbedtls_printf( "  > Write EHLO to server:" );
        fflush( stdout );

        gethostname( hostname, 32 );
        len = sprintf( (char *) buf, "EHLO %s\r\n", hostname );
        ret = write_ssl_and_get_response( &ssl, buf, len );
        if( ret < 200 || ret > 299 )
        {
            mbedtls_printf( " failed\n  ! server responded with %d\n\n", ret );
            goto exit;
        }
    }
    else
    {
        mbedtls_printf( "  > Get header from server:" );
        fflush( stdout );

        ret = write_and_get_response( &server_fd, buf, 0 );
        if( ret < 200 || ret > 299 )
        {
            mbedtls_printf( " failed\n  ! server responded with %d\n\n", ret );
            goto exit;
        }

        mbedtls_printf(" ok\n" );

        mbedtls_printf( "  > Write EHLO to server:" );
        fflush( stdout );

        gethostname( hostname, 32 );
        len = sprintf( (char *) buf, "EHLO %s\r\n", hostname );
        ret = write_and_get_response( &server_fd, buf, len );
        if( ret < 200 || ret > 299 )
        {
            mbedtls_printf( " failed\n  ! server responded with %d\n\n", ret );
            goto exit;
        }

        mbedtls_printf(" ok\n" );

        mbedtls_printf( "  > Write STARTTLS to server:" );
        fflush( stdout );

        gethostname( hostname, 32 );
        len = sprintf( (char *) buf, "STARTTLS\r\n" );
        ret = write_and_get_response( &server_fd, buf, len );
        if( ret < 200 || ret > 299 )
        {
            mbedtls_printf( " failed\n  ! server responded with %d\n\n", ret );
            goto exit;
        }

        mbedtls_printf(" ok\n" );

        if( do_handshake( &ssl ) != 0 )
            goto exit;
    }

#if defined(MBEDTLS_BASE64_C)
    if( opt.authentication )
    {
        mbedtls_printf( "  > Write AUTH LOGIN to server:" );
        fflush( stdout );

        len = sprintf( (char *) buf, "AUTH LOGIN\r\n" );
        ret = write_ssl_and_get_response( &ssl, buf, len );
        if( ret < 200 || ret > 399 )
        {
            mbedtls_printf( " failed\n  ! server responded with %d\n\n", ret );
            goto exit;
        }

        mbedtls_printf(" ok\n" );

        mbedtls_printf( "  > Write username to server: %s", opt.user_name );
        fflush( stdout );

        ret = mbedtls_base64_encode( base, sizeof( base ), &n, (const unsigned char *) opt.user_name,
                             strlen( opt.user_name ) );

        if( ret != 0 ) {
            mbedtls_printf( " failed\n  ! mbedtls_base64_encode returned %d\n\n", ret );
            goto exit;
        }
        len = sprintf( (char *) buf, "%s\r\n", base );
        ret = write_ssl_and_get_response( &ssl, buf, len );
        if( ret < 300 || ret > 399 )
        {
            mbedtls_printf( " failed\n  ! server responded with %d\n\n", ret );
            goto exit;
        }

        mbedtls_printf(" ok\n" );

        mbedtls_printf( "  > Write password to server: %s", opt.user_pwd );
        fflush( stdout );

        ret = mbedtls_base64_encode( base, sizeof( base ), &n, (const unsigned char *) opt.user_pwd,
                             strlen( opt.user_pwd ) );

        if( ret != 0 ) {
            mbedtls_printf( " failed\n  ! mbedtls_base64_encode returned %d\n\n", ret );
            goto exit;
        }
        len = sprintf( (char *) buf, "%s\r\n", base );
        ret = write_ssl_and_get_response( &ssl, buf, len );
        if( ret < 200 || ret > 399 )
        {
            mbedtls_printf( " failed\n  ! server responded with %d\n\n", ret );
            goto exit;
        }

        mbedtls_printf(" ok\n" );
    }
#endif

    mbedtls_printf( "  > Write MAIL FROM to server:" );
    fflush( stdout );

    len = sprintf( (char *) buf, "MAIL FROM:<%s>\r\n", opt.mail_from );
    ret = write_ssl_and_get_response( &ssl, buf, len );
    if( ret < 200 || ret > 299 )
    {
        mbedtls_printf( " failed\n  ! server responded with %d\n\n", ret );
        goto exit;
    }

    mbedtls_printf(" ok\n" );

    mbedtls_printf( "  > Write RCPT TO to server:" );
    fflush( stdout );

    len = sprintf( (char *) buf, "RCPT TO:<%s>\r\n", opt.mail_to );
    ret = write_ssl_and_get_response( &ssl, buf, len );
    if( ret < 200 || ret > 299 )
    {
        mbedtls_printf( " failed\n  ! server responded with %d\n\n", ret );
        goto exit;
    }

    mbedtls_printf(" ok\n" );

    mbedtls_printf( "  > Write DATA to server:" );
    fflush( stdout );

    len = sprintf( (char *) buf, "DATA\r\n" );
    ret = write_ssl_and_get_response( &ssl, buf, len );
    if( ret < 300 || ret > 399 )
    {
        mbedtls_printf( " failed\n  ! server responded with %d\n\n", ret );
        goto exit;
    }

    mbedtls_printf(" ok\n" );

    mbedtls_printf( "  > Write content to server:" );
    fflush( stdout );

    len = sprintf( (char *) buf, "From: %s\r\nSubject: mbed TLS Test mail\r\n\r\n"
            "This is a simple test mail from the "
            "mbed TLS mail client example.\r\n"
            "\r\n"
            "Enjoy!", opt.mail_from );
    ret = write_ssl_data( &ssl, buf, len );

    len = sprintf( (char *) buf, "\r\n.\r\n");
    ret = write_ssl_and_get_response( &ssl, buf, len );
    if( ret < 200 || ret > 299 )
    {
        mbedtls_printf( " failed\n  ! server responded with %d\n\n", ret );
        goto exit;
    }

    mbedtls_printf(" ok\n" );

    mbedtls_ssl_close_notify( &ssl );

    exit_code = MBEDTLS_EXIT_SUCCESS;

exit:

    mbedtls_net_free( &server_fd );
    mbedtls_x509_crt_free( &clicert );
    mbedtls_x509_crt_free( &cacert );
    mbedtls_pk_free( &pkey );
    mbedtls_ssl_free( &ssl );
    mbedtls_ssl_config_free( &conf );
    mbedtls_ctr_drbg_free( &ctr_drbg );
    mbedtls_entropy_free( &entropy );

#if defined(_WIN32)
    mbedtls_printf( "  + Press Enter to exit this program.\n" );
    fflush( stdout ); getchar();
#endif

    return( exit_code );
}