Beispiel #1
0
int dtls1_accept(SSL *s) {
  BUF_MEM *buf = NULL;
  void (*cb)(const SSL *ssl, int type, int value) = NULL;
  uint32_t alg_a;
  int ret = -1;
  int new_state, state, skip = 0;

  assert(s->handshake_func == dtls1_accept);
  assert(s->server);
  assert(SSL_IS_DTLS(s));

  ERR_clear_error();
  ERR_clear_system_error();

  if (s->info_callback != NULL) {
    cb = s->info_callback;
  } else if (s->ctx->info_callback != NULL) {
    cb = s->ctx->info_callback;
  }

  s->in_handshake++;

  for (;;) {
    state = s->state;

    switch (s->state) {
      case SSL_ST_ACCEPT:
        if (cb != NULL) {
          cb(s, SSL_CB_HANDSHAKE_START, 1);
        }

        if (s->init_buf == NULL) {
          buf = BUF_MEM_new();
          if (buf == NULL || !BUF_MEM_grow(buf, SSL3_RT_MAX_PLAIN_LENGTH)) {
            ret = -1;
            goto end;
          }
          s->init_buf = buf;
          buf = NULL;
        }

        s->init_num = 0;

        if (!ssl_init_wbio_buffer(s, 1)) {
          ret = -1;
          goto end;
        }

        if (!ssl3_init_handshake_buffer(s)) {
          OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
          ret = -1;
          goto end;
        }

        s->state = SSL3_ST_SR_CLNT_HELLO_A;
        break;

      case SSL3_ST_SR_CLNT_HELLO_A:
      case SSL3_ST_SR_CLNT_HELLO_B:
      case SSL3_ST_SR_CLNT_HELLO_C:
      case SSL3_ST_SR_CLNT_HELLO_D:
        s->shutdown = 0;
        ret = ssl3_get_client_hello(s);
        if (ret <= 0) {
          goto end;
        }
        dtls1_stop_timer(s);
        s->state = SSL3_ST_SW_SRVR_HELLO_A;
        s->init_num = 0;
        break;

      case SSL3_ST_SW_SRVR_HELLO_A:
      case SSL3_ST_SW_SRVR_HELLO_B:
        dtls1_start_timer(s);
        ret = ssl3_send_server_hello(s);
        if (ret <= 0) {
          goto end;
        }

        if (s->hit) {
          if (s->tlsext_ticket_expected) {
            s->state = SSL3_ST_SW_SESSION_TICKET_A;
          } else {
            s->state = SSL3_ST_SW_CHANGE_A;
          }
        } else {
          s->state = SSL3_ST_SW_CERT_A;
        }
        s->init_num = 0;
        break;

      case SSL3_ST_SW_CERT_A:
      case SSL3_ST_SW_CERT_B:
        if (ssl_cipher_has_server_public_key(s->s3->tmp.new_cipher)) {
          dtls1_start_timer(s);
          ret = ssl3_send_server_certificate(s);
          if (ret <= 0) {
            goto end;
          }
          if (s->s3->tmp.certificate_status_expected) {
            s->state = SSL3_ST_SW_CERT_STATUS_A;
          } else {
            s->state = SSL3_ST_SW_KEY_EXCH_A;
          }
        } else {
          skip = 1;
          s->state = SSL3_ST_SW_KEY_EXCH_A;
        }
        s->init_num = 0;
        break;

      case SSL3_ST_SW_CERT_STATUS_A:
      case SSL3_ST_SW_CERT_STATUS_B:
        ret = ssl3_send_certificate_status(s);
        if (ret <= 0) {
          goto end;
        }
        s->state = SSL3_ST_SW_KEY_EXCH_A;
        s->init_num = 0;
        break;

      case SSL3_ST_SW_KEY_EXCH_A:
      case SSL3_ST_SW_KEY_EXCH_B:
      case SSL3_ST_SW_KEY_EXCH_C:
        alg_a = s->s3->tmp.new_cipher->algorithm_auth;

        /* Send a ServerKeyExchange message if:
         * - The key exchange is ephemeral or anonymous
         *   Diffie-Hellman.
         * - There is a PSK identity hint.
         *
         * TODO(davidben): This logic is currently duplicated
         * in s3_srvr.c. Fix this. In the meantime, keep them
         * in sync. */
        if (ssl_cipher_requires_server_key_exchange(s->s3->tmp.new_cipher) ||
            ((alg_a & SSL_aPSK) && s->psk_identity_hint)) {
          dtls1_start_timer(s);
          ret = ssl3_send_server_key_exchange(s);
          if (ret <= 0) {
            goto end;
          }
        } else {
          skip = 1;
        }

        s->state = SSL3_ST_SW_CERT_REQ_A;
        s->init_num = 0;
        break;

      case SSL3_ST_SW_CERT_REQ_A:
      case SSL3_ST_SW_CERT_REQ_B:
        if (s->s3->tmp.cert_request) {
          dtls1_start_timer(s);
          ret = ssl3_send_certificate_request(s);
          if (ret <= 0) {
            goto end;
          }
        } else {
          skip = 1;
        }
        s->state = SSL3_ST_SW_SRVR_DONE_A;
        s->init_num = 0;
        break;

      case SSL3_ST_SW_SRVR_DONE_A:
      case SSL3_ST_SW_SRVR_DONE_B:
        dtls1_start_timer(s);
        ret = ssl3_send_server_done(s);
        if (ret <= 0) {
          goto end;
        }
        s->s3->tmp.next_state = SSL3_ST_SR_CERT_A;
        s->state = SSL3_ST_SW_FLUSH;
        s->init_num = 0;
        break;

      case SSL3_ST_SW_FLUSH:
        s->rwstate = SSL_WRITING;
        if (BIO_flush(s->wbio) <= 0) {
          ret = -1;
          goto end;
        }
        s->rwstate = SSL_NOTHING;
        s->state = s->s3->tmp.next_state;
        break;

      case SSL3_ST_SR_CERT_A:
      case SSL3_ST_SR_CERT_B:
        if (s->s3->tmp.cert_request) {
          ret = ssl3_get_client_certificate(s);
          if (ret <= 0) {
            goto end;
          }
        }
        s->init_num = 0;
        s->state = SSL3_ST_SR_KEY_EXCH_A;
        break;

      case SSL3_ST_SR_KEY_EXCH_A:
      case SSL3_ST_SR_KEY_EXCH_B:
      case SSL3_ST_SR_KEY_EXCH_C:
        ret = ssl3_get_client_key_exchange(s);
        if (ret <= 0) {
          goto end;
        }
        s->state = SSL3_ST_SR_CERT_VRFY_A;
        s->init_num = 0;
        break;

      case SSL3_ST_SR_CERT_VRFY_A:
      case SSL3_ST_SR_CERT_VRFY_B:
        ret = ssl3_get_cert_verify(s);
        if (ret <= 0) {
          goto end;
        }
        s->state = SSL3_ST_SR_CHANGE;
        s->init_num = 0;
        break;

      case SSL3_ST_SR_CHANGE:
        ret = s->method->ssl_read_change_cipher_spec(s);
        if (ret <= 0) {
          goto end;
        }

        if (!ssl3_do_change_cipher_spec(s)) {
          ret = -1;
          goto end;
        }

        s->state = SSL3_ST_SR_FINISHED_A;
        break;

      case SSL3_ST_SR_FINISHED_A:
      case SSL3_ST_SR_FINISHED_B:
        ret =
            ssl3_get_finished(s, SSL3_ST_SR_FINISHED_A, SSL3_ST_SR_FINISHED_B);
        if (ret <= 0) {
          goto end;
        }
        dtls1_stop_timer(s);
        if (s->hit) {
          s->state = SSL_ST_OK;
        } else if (s->tlsext_ticket_expected) {
          s->state = SSL3_ST_SW_SESSION_TICKET_A;
        } else {
          s->state = SSL3_ST_SW_CHANGE_A;
        }
        s->init_num = 0;
        break;

      case SSL3_ST_SW_SESSION_TICKET_A:
      case SSL3_ST_SW_SESSION_TICKET_B:
        ret = ssl3_send_new_session_ticket(s);
        if (ret <= 0) {
          goto end;
        }
        s->state = SSL3_ST_SW_CHANGE_A;
        s->init_num = 0;
        break;

      case SSL3_ST_SW_CHANGE_A:
      case SSL3_ST_SW_CHANGE_B:
        s->session->cipher = s->s3->tmp.new_cipher;
        if (!s->enc_method->setup_key_block(s)) {
          ret = -1;
          goto end;
        }

        ret = dtls1_send_change_cipher_spec(s, SSL3_ST_SW_CHANGE_A,
                                            SSL3_ST_SW_CHANGE_B);

        if (ret <= 0) {
          goto end;
        }

        s->state = SSL3_ST_SW_FINISHED_A;
        s->init_num = 0;

        if (!s->enc_method->change_cipher_state(
                s, SSL3_CHANGE_CIPHER_SERVER_WRITE)) {
          ret = -1;
          goto end;
        }
        break;

      case SSL3_ST_SW_FINISHED_A:
      case SSL3_ST_SW_FINISHED_B:
        ret =
            ssl3_send_finished(s, SSL3_ST_SW_FINISHED_A, SSL3_ST_SW_FINISHED_B,
                               s->enc_method->server_finished_label,
                               s->enc_method->server_finished_label_len);
        if (ret <= 0) {
          goto end;
        }
        s->state = SSL3_ST_SW_FLUSH;
        if (s->hit) {
          s->s3->tmp.next_state = SSL3_ST_SR_CHANGE;
        } else {
          s->s3->tmp.next_state = SSL_ST_OK;
        }
        s->init_num = 0;
        break;

      case SSL_ST_OK:
        ssl3_cleanup_key_block(s);

        /* remove buffering on output */
        ssl_free_wbio_buffer(s);

        s->init_num = 0;
        s->s3->initial_handshake_complete = 1;

        ssl_update_cache(s, SSL_SESS_CACHE_SERVER);

        if (cb != NULL) {
          cb(s, SSL_CB_HANDSHAKE_DONE, 1);
        }

        ret = 1;

        /* done handshaking, next message is client hello */
        s->d1->handshake_read_seq = 0;
        /* next message is server hello */
        s->d1->handshake_write_seq = 0;
        s->d1->next_handshake_write_seq = 0;
        goto end;

      default:
        OPENSSL_PUT_ERROR(SSL, SSL_R_UNKNOWN_STATE);
        ret = -1;
        goto end;
    }

    if (!s->s3->tmp.reuse_message && !skip) {
      if (cb != NULL && s->state != state) {
        new_state = s->state;
        s->state = state;
        cb(s, SSL_CB_ACCEPT_LOOP, 1);
        s->state = new_state;
      }
    }
    skip = 0;
  }

end:
  s->in_handshake--;
  BUF_MEM_free(buf);
  if (cb != NULL) {
    cb(s, SSL_CB_ACCEPT_EXIT, ret);
  }
  return ret;
}
Beispiel #2
0
/* Return up to 'len' payload bytes received in 'type' records.
 * 'type' is one of the following:
 *
 *   -  SSL3_RT_HANDSHAKE (when ssl3_get_message calls us)
 *   -  SSL3_RT_APPLICATION_DATA (when ssl3_read calls us)
 *   -  0 (during a shutdown, no data has to be returned)
 *
 * If we don't have stored data to work from, read a SSL/TLS record first
 * (possibly multiple records if we still don't have anything to return).
 *
 * This function must handle any surprises the peer may have for us, such as
 * Alert records (e.g. close_notify), ChangeCipherSpec records (not really
 * a surprise, but handled as if it were), or renegotiation requests.
 * Also if record payloads contain fragments too small to process, we store
 * them until there is enough for the respective protocol (the record protocol
 * may use arbitrary fragmentation and even interleaving):
 *     Change cipher spec protocol
 *             just 1 byte needed, no need for keeping anything stored
 *     Alert protocol
 *             2 bytes needed (AlertLevel, AlertDescription)
 *     Handshake protocol
 *             4 bytes needed (HandshakeType, uint24 length) -- we just have
 *             to detect unexpected Client Hello and Hello Request messages
 *             here, anything else is handled by higher layers
 *     Application data protocol
 *             none of our business
 */
int ssl3_read_bytes(SSL *s, int type, uint8_t *buf, int len, int peek) {
  int al, i, ret;
  unsigned int n;
  SSL3_RECORD *rr;
  void (*cb)(const SSL *ssl, int type2, int val) = NULL;

  if ((type && type != SSL3_RT_APPLICATION_DATA && type != SSL3_RT_HANDSHAKE) ||
      (peek && type != SSL3_RT_APPLICATION_DATA)) {
    OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
    return -1;
  }

  if (type == SSL3_RT_HANDSHAKE && s->s3->handshake_fragment_len > 0) {
    /* (partially) satisfy request from storage */
    uint8_t *src = s->s3->handshake_fragment;
    uint8_t *dst = buf;
    unsigned int k;

    /* peek == 0 */
    n = 0;
    while (len > 0 && s->s3->handshake_fragment_len > 0) {
      *dst++ = *src++;
      len--;
      s->s3->handshake_fragment_len--;
      n++;
    }
    /* move any remaining fragment bytes: */
    for (k = 0; k < s->s3->handshake_fragment_len; k++) {
      s->s3->handshake_fragment[k] = *src++;
    }
    return n;
  }

  /* Now s->s3->handshake_fragment_len == 0 if type == SSL3_RT_HANDSHAKE. */

  /* This may require multiple iterations. False Start will cause
   * |s->handshake_func| to signal success one step early, but the handshake
   * must be completely finished before other modes are accepted.
   *
   * TODO(davidben): Move this check up to a higher level. */
  while (!s->in_handshake && SSL_in_init(s)) {
    assert(type == SSL3_RT_APPLICATION_DATA);
    i = s->handshake_func(s);
    if (i < 0) {
      return i;
    }
    if (i == 0) {
      OPENSSL_PUT_ERROR(SSL, SSL_R_SSL_HANDSHAKE_FAILURE);
      return -1;
    }
  }

start:
  s->rwstate = SSL_NOTHING;

  /* s->s3->rrec.type    - is the type of record
   * s->s3->rrec.data    - data
   * s->s3->rrec.off     - offset into 'data' for next read
   * s->s3->rrec.length  - number of bytes. */
  rr = &s->s3->rrec;

  /* get new packet if necessary */
  if (rr->length == 0) {
    ret = ssl3_get_record(s);
    if (ret <= 0) {
      return ret;
    }
  }

  /* we now have a packet which can be read and processed */

  /* |change_cipher_spec is set when we receive a ChangeCipherSpec and reset by
   * ssl3_get_finished. */
  if (s->s3->change_cipher_spec && rr->type != SSL3_RT_HANDSHAKE &&
      rr->type != SSL3_RT_ALERT) {
    al = SSL_AD_UNEXPECTED_MESSAGE;
    OPENSSL_PUT_ERROR(SSL, SSL_R_DATA_BETWEEN_CCS_AND_FINISHED);
    goto f_err;
  }

  /* If we are expecting a ChangeCipherSpec, it is illegal to receive a
   * Handshake record. */
  if (rr->type == SSL3_RT_HANDSHAKE && (s->s3->flags & SSL3_FLAGS_EXPECT_CCS)) {
    al = SSL_AD_UNEXPECTED_MESSAGE;
    OPENSSL_PUT_ERROR(SSL, SSL_R_HANDSHAKE_RECORD_BEFORE_CCS);
    goto f_err;
  }

  /* If the other end has shut down, throw anything we read away (even in
   * 'peek' mode) */
  if (s->shutdown & SSL_RECEIVED_SHUTDOWN) {
    rr->length = 0;
    s->rwstate = SSL_NOTHING;
    return 0;
  }

  if (type != 0 && type == rr->type) {
    s->s3->warning_alert_count = 0;

    /* SSL3_RT_APPLICATION_DATA or SSL3_RT_HANDSHAKE */
    /* make sure that we are not getting application data when we are doing a
     * handshake for the first time */
    if (SSL_in_init(s) && type == SSL3_RT_APPLICATION_DATA &&
        s->aead_read_ctx == NULL) {
      /* TODO(davidben): Is this check redundant with the handshake_func
       * check? */
      al = SSL_AD_UNEXPECTED_MESSAGE;
      OPENSSL_PUT_ERROR(SSL, SSL_R_APP_DATA_IN_HANDSHAKE);
      goto f_err;
    }

    /* Discard empty records. */
    if (rr->length == 0) {
      goto start;
    }

    if (len <= 0) {
      return len;
    }

    if ((unsigned int)len > rr->length) {
      n = rr->length;
    } else {
      n = (unsigned int)len;
    }

    memcpy(buf, &(rr->data[rr->off]), n);
    if (!peek) {
      rr->length -= n;
      rr->off += n;
      if (rr->length == 0) {
        rr->off = 0;
        /* The record has been consumed, so we may now clear the buffer. */
        ssl_read_buffer_discard(s);
      }
    }

    return n;
  }

  /* Process unexpected records. */

  if (rr->type == SSL3_RT_HANDSHAKE) {
    /* If peer renegotiations are disabled, all out-of-order handshake records
     * are fatal. Renegotiations as a server are never supported. */
    if (s->server || !ssl3_can_renegotiate(s)) {
      al = SSL_AD_NO_RENEGOTIATION;
      OPENSSL_PUT_ERROR(SSL, SSL_R_NO_RENEGOTIATION);
      goto f_err;
    }

    /* HelloRequests may be fragmented across multiple records. */
    const size_t size = sizeof(s->s3->handshake_fragment);
    const size_t avail = size - s->s3->handshake_fragment_len;
    const size_t todo = (rr->length < avail) ? rr->length : avail;
    memcpy(s->s3->handshake_fragment + s->s3->handshake_fragment_len,
           &rr->data[rr->off], todo);
    rr->off += todo;
    rr->length -= todo;
    s->s3->handshake_fragment_len += todo;
    if (s->s3->handshake_fragment_len < size) {
      goto start; /* fragment was too small */
    }

    /* Parse out and consume a HelloRequest. */
    if (s->s3->handshake_fragment[0] != SSL3_MT_HELLO_REQUEST ||
        s->s3->handshake_fragment[1] != 0 ||
        s->s3->handshake_fragment[2] != 0 ||
        s->s3->handshake_fragment[3] != 0) {
      al = SSL_AD_DECODE_ERROR;
      OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_HELLO_REQUEST);
      goto f_err;
    }
    s->s3->handshake_fragment_len = 0;

    if (s->msg_callback) {
      s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
                      s->s3->handshake_fragment, 4, s, s->msg_callback_arg);
    }

    if (!SSL_is_init_finished(s) || !s->s3->initial_handshake_complete) {
      /* This cannot happen. If a handshake is in progress, |type| must be
       * |SSL3_RT_HANDSHAKE|. */
      assert(0);
      OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
      goto err;
    }

    /* Renegotiation is only supported at quiescent points in the application
     * protocol, namely in HTTPS, just before reading the HTTP response. Require
     * the record-layer be idle and avoid complexities of sending a handshake
     * record while an application_data record is being written. */
    if (ssl_write_buffer_is_pending(s)) {
      al = SSL_AD_NO_RENEGOTIATION;
      OPENSSL_PUT_ERROR(SSL, SSL_R_NO_RENEGOTIATION);
      goto f_err;
    }

    /* Begin a new handshake. */
    s->s3->total_renegotiations++;
    s->state = SSL_ST_CONNECT;
    i = s->handshake_func(s);
    if (i < 0) {
      return i;
    }
    if (i == 0) {
      OPENSSL_PUT_ERROR(SSL, SSL_R_SSL_HANDSHAKE_FAILURE);
      return -1;
    }

    /* The handshake completed synchronously. Continue reading records. */
    goto start;
  }

  /* If an alert record, process one alert out of the record. Note that we allow
   * a single record to contain multiple alerts. */
  if (rr->type == SSL3_RT_ALERT) {
    /* Alerts may not be fragmented. */
    if (rr->length < 2) {
      al = SSL_AD_DECODE_ERROR;
      OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_ALERT);
      goto f_err;
    }

    if (s->msg_callback) {
      s->msg_callback(0, s->version, SSL3_RT_ALERT, &rr->data[rr->off], 2, s,
                      s->msg_callback_arg);
    }
    const uint8_t alert_level = rr->data[rr->off++];
    const uint8_t alert_descr = rr->data[rr->off++];
    rr->length -= 2;

    if (s->info_callback != NULL) {
      cb = s->info_callback;
    } else if (s->ctx->info_callback != NULL) {
      cb = s->ctx->info_callback;
    }

    if (cb != NULL) {
      uint16_t alert = (alert_level << 8) | alert_descr;
      cb(s, SSL_CB_READ_ALERT, alert);
    }

    if (alert_level == SSL3_AL_WARNING) {
      s->s3->warn_alert = alert_descr;
      if (alert_descr == SSL_AD_CLOSE_NOTIFY) {
        s->shutdown |= SSL_RECEIVED_SHUTDOWN;
        return 0;
      }

      /* This is a warning but we receive it if we requested renegotiation and
       * the peer denied it. Terminate with a fatal alert because if
       * application tried to renegotiatie it presumably had a good reason and
       * expects it to succeed.
       *
       * In future we might have a renegotiation where we don't care if the
       * peer refused it where we carry on. */
      else if (alert_descr == SSL_AD_NO_RENEGOTIATION) {
        al = SSL_AD_HANDSHAKE_FAILURE;
        OPENSSL_PUT_ERROR(SSL, SSL_R_NO_RENEGOTIATION);
        goto f_err;
      }

      s->s3->warning_alert_count++;
      if (s->s3->warning_alert_count > kMaxWarningAlerts) {
        al = SSL_AD_UNEXPECTED_MESSAGE;
        OPENSSL_PUT_ERROR(SSL, SSL_R_TOO_MANY_WARNING_ALERTS);
        goto f_err;
      }
    } else if (alert_level == SSL3_AL_FATAL) {
      char tmp[16];

      s->rwstate = SSL_NOTHING;
      s->s3->fatal_alert = alert_descr;
      OPENSSL_PUT_ERROR(SSL, SSL_AD_REASON_OFFSET + alert_descr);
      BIO_snprintf(tmp, sizeof(tmp), "%d", alert_descr);
      ERR_add_error_data(2, "SSL alert number ", tmp);
      s->shutdown |= SSL_RECEIVED_SHUTDOWN;
      SSL_CTX_remove_session(s->ctx, s->session);
      return 0;
    } else {
      al = SSL_AD_ILLEGAL_PARAMETER;
      OPENSSL_PUT_ERROR(SSL, SSL_R_UNKNOWN_ALERT_TYPE);
      goto f_err;
    }

    goto start;
  }

  if (s->shutdown & SSL_SENT_SHUTDOWN) {
    /* close_notify has been sent, so discard all records other than alerts. */
    rr->length = 0;
    goto start;
  }

  if (rr->type == SSL3_RT_CHANGE_CIPHER_SPEC) {
    /* 'Change Cipher Spec' is just a single byte, so we know exactly what the
     * record payload has to look like */
    if (rr->length != 1 || rr->off != 0 || rr->data[0] != SSL3_MT_CCS) {
      al = SSL_AD_ILLEGAL_PARAMETER;
      OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_CHANGE_CIPHER_SPEC);
      goto f_err;
    }

    /* Check we have a cipher to change to */
    if (s->s3->tmp.new_cipher == NULL) {
      al = SSL_AD_UNEXPECTED_MESSAGE;
      OPENSSL_PUT_ERROR(SSL, SSL_R_CCS_RECEIVED_EARLY);
      goto f_err;
    }

    if (!(s->s3->flags & SSL3_FLAGS_EXPECT_CCS)) {
      al = SSL_AD_UNEXPECTED_MESSAGE;
      OPENSSL_PUT_ERROR(SSL, SSL_R_CCS_RECEIVED_EARLY);
      goto f_err;
    }

    s->s3->flags &= ~SSL3_FLAGS_EXPECT_CCS;

    rr->length = 0;

    if (s->msg_callback) {
      s->msg_callback(0, s->version, SSL3_RT_CHANGE_CIPHER_SPEC, rr->data, 1, s,
                      s->msg_callback_arg);
    }

    s->s3->change_cipher_spec = 1;
    if (!ssl3_do_change_cipher_spec(s)) {
      goto err;
    } else {
      goto start;
    }
  }

  /* We already handled these. */
  assert(rr->type != SSL3_RT_CHANGE_CIPHER_SPEC && rr->type != SSL3_RT_ALERT &&
         rr->type != SSL3_RT_HANDSHAKE);

  al = SSL_AD_UNEXPECTED_MESSAGE;
  OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_RECORD);

f_err:
  ssl3_send_alert(s, SSL3_AL_FATAL, al);
err:
  return -1;
}
Beispiel #3
0
MSG_PROCESS_RETURN tls_process_change_cipher_spec(SSL *s, PACKET *pkt)
{
    int al;
    long remain;

    remain = PACKET_remaining(pkt);
    /*
     * 'Change Cipher Spec' is just a single byte, which should already have
     * been consumed by ssl_get_message() so there should be no bytes left,
     * unless we're using DTLS1_BAD_VER, which has an extra 2 bytes
     */
    if (SSL_IS_DTLS(s)) {
        if ((s->version == DTLS1_BAD_VER
             && remain != DTLS1_CCS_HEADER_LENGTH + 1)
            || (s->version != DTLS1_BAD_VER
                && remain != DTLS1_CCS_HEADER_LENGTH - 1)) {
            al = SSL_AD_ILLEGAL_PARAMETER;
            SSLerr(SSL_F_TLS_PROCESS_CHANGE_CIPHER_SPEC,
                   SSL_R_BAD_CHANGE_CIPHER_SPEC);
            goto f_err;
        }
    } else {
        if (remain != 0) {
            al = SSL_AD_ILLEGAL_PARAMETER;
            SSLerr(SSL_F_TLS_PROCESS_CHANGE_CIPHER_SPEC,
                   SSL_R_BAD_CHANGE_CIPHER_SPEC);
            goto f_err;
        }
    }

    /* Check we have a cipher to change to */
    if (s->s3->tmp.new_cipher == NULL) {
        al = SSL_AD_UNEXPECTED_MESSAGE;
        SSLerr(SSL_F_TLS_PROCESS_CHANGE_CIPHER_SPEC, SSL_R_CCS_RECEIVED_EARLY);
        goto f_err;
    }

    s->s3->change_cipher_spec = 1;
    if (!ssl3_do_change_cipher_spec(s)) {
        al = SSL_AD_INTERNAL_ERROR;
        SSLerr(SSL_F_TLS_PROCESS_CHANGE_CIPHER_SPEC, ERR_R_INTERNAL_ERROR);
        goto f_err;
    }

    if (SSL_IS_DTLS(s)) {
        dtls1_reset_seq_numbers(s, SSL3_CC_READ);

        if (s->version == DTLS1_BAD_VER)
            s->d1->handshake_read_seq++;

#ifndef OPENSSL_NO_SCTP
        /*
         * Remember that a CCS has been received, so that an old key of
         * SCTP-Auth can be deleted when a CCS is sent. Will be ignored if no
         * SCTP is used
         */
        BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_AUTH_CCS_RCVD, 1, NULL);
#endif
    }

    return MSG_PROCESS_CONTINUE_READING;
 f_err:
    ssl3_send_alert(s, SSL3_AL_FATAL, al);
    ossl_statem_set_error(s);
    return MSG_PROCESS_ERROR;
}
Beispiel #4
0
/*-
 * Return up to 'len' payload bytes received in 'type' records.
 * 'type' is one of the following:
 *
 *   -  SSL3_RT_HANDSHAKE (when ssl3_get_message calls us)
 *   -  SSL3_RT_APPLICATION_DATA (when ssl3_read calls us)
 *   -  0 (during a shutdown, no data has to be returned)
 *
 * If we don't have stored data to work from, read a SSL/TLS record first
 * (possibly multiple records if we still don't have anything to return).
 *
 * This function must handle any surprises the peer may have for us, such as
 * Alert records (e.g. close_notify), ChangeCipherSpec records (not really
 * a surprise, but handled as if it were), or renegotiation requests.
 * Also if record payloads contain fragments too small to process, we store
 * them until there is enough for the respective protocol (the record protocol
 * may use arbitrary fragmentation and even interleaving):
 *     Change cipher spec protocol
 *             just 1 byte needed, no need for keeping anything stored
 *     Alert protocol
 *             2 bytes needed (AlertLevel, AlertDescription)
 *     Handshake protocol
 *             4 bytes needed (HandshakeType, uint24 length) -- we just have
 *             to detect unexpected Client Hello and Hello Request messages
 *             here, anything else is handled by higher layers
 *     Application data protocol
 *             none of our business
 */
int dtls1_read_bytes(SSL *s, int type, unsigned char *buf, int len, int peek)
{
    int al, i, j, ret;
    unsigned int n;
    SSL3_RECORD *rr;
    void (*cb) (const SSL *ssl, int type2, int val) = NULL;

    if (!SSL3_BUFFER_is_initialised(&s->rlayer.rbuf)) {
        /* Not initialized yet */
        if (!ssl3_setup_buffers(s))
            return (-1);
    }

    if ((type && (type != SSL3_RT_APPLICATION_DATA) &&
         (type != SSL3_RT_HANDSHAKE)) ||
        (peek && (type != SSL3_RT_APPLICATION_DATA))) {
        SSLerr(SSL_F_DTLS1_READ_BYTES, ERR_R_INTERNAL_ERROR);
        return -1;
    }

    /*
     * check whether there's a handshake message (client hello?) waiting
     */
    if ((ret = have_handshake_fragment(s, type, buf, len, peek)))
        return ret;

    /*
     * Now s->rlayer.d->handshake_fragment_len == 0 if
     * type == SSL3_RT_HANDSHAKE.
     */

#ifndef OPENSSL_NO_SCTP
    /*
     * Continue handshake if it had to be interrupted to read app data with
     * SCTP.
     */
    if ((!s->in_handshake && SSL_in_init(s)) ||
        (BIO_dgram_is_sctp(SSL_get_rbio(s)) &&
         (s->state == DTLS1_SCTP_ST_SR_READ_SOCK
          || s->state == DTLS1_SCTP_ST_CR_READ_SOCK)
         && s->s3->in_read_app_data != 2))
#else
    if (!s->in_handshake && SSL_in_init(s))
#endif
    {
        /* type == SSL3_RT_APPLICATION_DATA */
        i = s->handshake_func(s);
        if (i < 0)
            return (i);
        if (i == 0) {
            SSLerr(SSL_F_DTLS1_READ_BYTES, SSL_R_SSL_HANDSHAKE_FAILURE);
            return (-1);
        }
    }

 start:
    s->rwstate = SSL_NOTHING;

    /*-
     * s->s3->rrec.type         - is the type of record
     * s->s3->rrec.data,    - data
     * s->s3->rrec.off,     - offset into 'data' for next read
     * s->s3->rrec.length,  - number of bytes.
     */
    rr = &s->rlayer.rrec;

    /*
     * We are not handshaking and have no data yet, so process data buffered
     * during the last handshake in advance, if any.
     */
    if (s->state == SSL_ST_OK && SSL3_RECORD_get_length(rr) == 0) {
        pitem *item;
        item = pqueue_pop(s->rlayer.d->buffered_app_data.q);
        if (item) {
#ifndef OPENSSL_NO_SCTP
            /* Restore bio_dgram_sctp_rcvinfo struct */
            if (BIO_dgram_is_sctp(SSL_get_rbio(s))) {
                DTLS1_RECORD_DATA *rdata = (DTLS1_RECORD_DATA *)item->data;
                BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SCTP_SET_RCVINFO,
                         sizeof(rdata->recordinfo), &rdata->recordinfo);
            }
#endif

            dtls1_copy_record(s, item);

            OPENSSL_free(item->data);
            pitem_free(item);
        }
    }

    /* Check for timeout */
    if (dtls1_handle_timeout(s) > 0)
        goto start;

    /* get new packet if necessary */
    if ((SSL3_RECORD_get_length(rr) == 0)
            || (s->rlayer.rstate == SSL_ST_READ_BODY)) {
        ret = dtls1_get_record(s);
        if (ret <= 0) {
            ret = dtls1_read_failed(s, ret);
            /* anything other than a timeout is an error */
            if (ret <= 0)
                return (ret);
            else
                goto start;
        }
    }

    if (s->d1->listen && rr->type != SSL3_RT_HANDSHAKE) {
        SSL3_RECORD_set_length(rr, 0);
        goto start;
    }

    /* we now have a packet which can be read and processed */

    if (s->s3->change_cipher_spec /* set when we receive ChangeCipherSpec,
                                   * reset by ssl3_get_finished */
        && (SSL3_RECORD_get_type(rr) != SSL3_RT_HANDSHAKE)) {
        /*
         * We now have application data between CCS and Finished. Most likely
         * the packets were reordered on their way, so buffer the application
         * data for later processing rather than dropping the connection.
         */
        if (dtls1_buffer_record(s, &(s->rlayer.d->buffered_app_data),
            SSL3_RECORD_get_seq_num(rr)) < 0) {
            SSLerr(SSL_F_DTLS1_READ_BYTES, ERR_R_INTERNAL_ERROR);
            return -1;
        }
        SSL3_RECORD_set_length(rr, 0);
        goto start;
    }

    /*
     * If the other end has shut down, throw anything we read away (even in
     * 'peek' mode)
     */
    if (s->shutdown & SSL_RECEIVED_SHUTDOWN) {
        SSL3_RECORD_set_length(rr, 0);
        s->rwstate = SSL_NOTHING;
        return (0);
    }

    if (type == SSL3_RECORD_get_type(rr)) {
        /* SSL3_RT_APPLICATION_DATA or
         * SSL3_RT_HANDSHAKE */
        /*
         * make sure that we are not getting application data when we are
         * doing a handshake for the first time
         */
        if (SSL_in_init(s) && (type == SSL3_RT_APPLICATION_DATA) &&
            (s->enc_read_ctx == NULL)) {
            al = SSL_AD_UNEXPECTED_MESSAGE;
            SSLerr(SSL_F_DTLS1_READ_BYTES, SSL_R_APP_DATA_IN_HANDSHAKE);
            goto f_err;
        }

        if (len <= 0)
            return (len);

        if ((unsigned int)len > SSL3_RECORD_get_length(rr))
            n = SSL3_RECORD_get_length(rr);
        else
            n = (unsigned int)len;

        memcpy(buf, &(SSL3_RECORD_get_data(rr)[SSL3_RECORD_get_off(rr)]), n);
        if (!peek) {
            SSL3_RECORD_add_length(rr, -n);
            SSL3_RECORD_add_off(rr, n);
            if (SSL3_RECORD_get_length(rr) == 0) {
                s->rlayer.rstate = SSL_ST_READ_HEADER;
                SSL3_RECORD_set_off(rr, 0);
            }
        }
#ifndef OPENSSL_NO_SCTP
        /*
         * We were about to renegotiate but had to read belated application
         * data first, so retry.
         */
        if (BIO_dgram_is_sctp(SSL_get_rbio(s)) &&
            SSL3_RECORD_get_type(rr) == SSL3_RT_APPLICATION_DATA &&
            (s->state == DTLS1_SCTP_ST_SR_READ_SOCK
             || s->state == DTLS1_SCTP_ST_CR_READ_SOCK)) {
            s->rwstate = SSL_READING;
            BIO_clear_retry_flags(SSL_get_rbio(s));
            BIO_set_retry_read(SSL_get_rbio(s));
        }

        /*
         * We might had to delay a close_notify alert because of reordered
         * app data. If there was an alert and there is no message to read
         * anymore, finally set shutdown.
         */
        if (BIO_dgram_is_sctp(SSL_get_rbio(s)) &&
            s->d1->shutdown_received
            && !BIO_dgram_sctp_msg_waiting(SSL_get_rbio(s))) {
            s->shutdown |= SSL_RECEIVED_SHUTDOWN;
            return (0);
        }
#endif
        return (n);
    }

    /*
     * If we get here, then type != rr->type; if we have a handshake message,
     * then it was unexpected (Hello Request or Client Hello).
     */

    /*
     * In case of record types for which we have 'fragment' storage, fill
     * that so that we can process the data at a fixed place.
     */
    {
        unsigned int k, dest_maxlen = 0;
        unsigned char *dest = NULL;
        unsigned int *dest_len = NULL;

        if (SSL3_RECORD_get_type(rr) == SSL3_RT_HANDSHAKE) {
            dest_maxlen = sizeof s->rlayer.d->handshake_fragment;
            dest = s->rlayer.d->handshake_fragment;
            dest_len = &s->rlayer.d->handshake_fragment_len;
        } else if (SSL3_RECORD_get_type(rr) == SSL3_RT_ALERT) {
            dest_maxlen = sizeof(s->rlayer.d->alert_fragment);
            dest = s->rlayer.d->alert_fragment;
            dest_len = &s->rlayer.d->alert_fragment_len;
        }
#ifndef OPENSSL_NO_HEARTBEATS
        else if (SSL3_RECORD_get_type(rr) == TLS1_RT_HEARTBEAT) {
            /* We allow a 0 return */
            if (dtls1_process_heartbeat(s, SSL3_RECORD_get_data(rr),
                    SSL3_RECORD_get_length(rr)) < 0) {
                return -1;
            }
            /* Exit and notify application to read again */
            SSL3_RECORD_set_length(rr, 0);
            s->rwstate = SSL_READING;
            BIO_clear_retry_flags(SSL_get_rbio(s));
            BIO_set_retry_read(SSL_get_rbio(s));
            return (-1);
        }
#endif
        /* else it's a CCS message, or application data or wrong */
        else if (SSL3_RECORD_get_type(rr) != SSL3_RT_CHANGE_CIPHER_SPEC) {
            /*
             * Application data while renegotiating is allowed. Try again
             * reading.
             */
            if (SSL3_RECORD_get_type(rr)  == SSL3_RT_APPLICATION_DATA) {
                BIO *bio;
                s->s3->in_read_app_data = 2;
                bio = SSL_get_rbio(s);
                s->rwstate = SSL_READING;
                BIO_clear_retry_flags(bio);
                BIO_set_retry_read(bio);
                return (-1);
            }

            /* Not certain if this is the right error handling */
            al = SSL_AD_UNEXPECTED_MESSAGE;
            SSLerr(SSL_F_DTLS1_READ_BYTES, SSL_R_UNEXPECTED_RECORD);
            goto f_err;
        }

        if (dest_maxlen > 0) {
            /*
             * XDTLS: In a pathalogical case, the Client Hello may be
             * fragmented--don't always expect dest_maxlen bytes
             */
            if (SSL3_RECORD_get_length(rr)  < dest_maxlen) {
#ifdef DTLS1_AD_MISSING_HANDSHAKE_MESSAGE
                /*
                 * for normal alerts rr->length is 2, while
                 * dest_maxlen is 7 if we were to handle this
                 * non-existing alert...
                 */
                FIX ME
#endif
                s->rlayer.rstate = SSL_ST_READ_HEADER;
                SSL3_RECORD_set_length(rr, 0);
                goto start;
            }

            /* now move 'n' bytes: */
            for (k = 0; k < dest_maxlen; k++) {
                dest[k] = SSL3_RECORD_get_data(rr)[SSL3_RECORD_get_off(rr)];
                SSL3_RECORD_add_off(rr, 1);
                SSL3_RECORD_add_length(rr, -1);
            }
            *dest_len = dest_maxlen;
        }
    }

    /*-
     * s->rlayer.d->handshake_fragment_len == 12  iff  rr->type == SSL3_RT_HANDSHAKE;
     * s->rlayer.d->alert_fragment_len == 7      iff  rr->type == SSL3_RT_ALERT.
     * (Possibly rr is 'empty' now, i.e. rr->length may be 0.)
     */

    /* If we are a client, check for an incoming 'Hello Request': */
    if ((!s->server) &&
        (s->rlayer.d->handshake_fragment_len >= DTLS1_HM_HEADER_LENGTH) &&
        (s->rlayer.d->handshake_fragment[0] == SSL3_MT_HELLO_REQUEST) &&
        (s->session != NULL) && (s->session->cipher != NULL)) {
        s->rlayer.d->handshake_fragment_len = 0;

        if ((s->rlayer.d->handshake_fragment[1] != 0) ||
            (s->rlayer.d->handshake_fragment[2] != 0) ||
            (s->rlayer.d->handshake_fragment[3] != 0)) {
            al = SSL_AD_DECODE_ERROR;
            SSLerr(SSL_F_DTLS1_READ_BYTES, SSL_R_BAD_HELLO_REQUEST);
            goto err;
        }

        /*
         * no need to check sequence number on HELLO REQUEST messages
         */

        if (s->msg_callback)
            s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
                            s->rlayer.d->handshake_fragment, 4, s,
                            s->msg_callback_arg);

        if (SSL_is_init_finished(s) &&
            !(s->s3->flags & SSL3_FLAGS_NO_RENEGOTIATE_CIPHERS) &&
            !s->s3->renegotiate) {
            s->d1->handshake_read_seq++;
            s->new_session = 1;
            ssl3_renegotiate(s);
            if (ssl3_renegotiate_check(s)) {
                i = s->handshake_func(s);
                if (i < 0)
                    return (i);
                if (i == 0) {
                    SSLerr(SSL_F_DTLS1_READ_BYTES,
                           SSL_R_SSL_HANDSHAKE_FAILURE);
                    return (-1);
                }

                if (!(s->mode & SSL_MODE_AUTO_RETRY)) {
                    if (SSL3_BUFFER_get_left(&s->rlayer.rbuf) == 0) {
                        /* no read-ahead left? */
                        BIO *bio;
                        /*
                         * In the case where we try to read application data,
                         * but we trigger an SSL handshake, we return -1 with
                         * the retry option set.  Otherwise renegotiation may
                         * cause nasty problems in the blocking world
                         */
                        s->rwstate = SSL_READING;
                        bio = SSL_get_rbio(s);
                        BIO_clear_retry_flags(bio);
                        BIO_set_retry_read(bio);
                        return (-1);
                    }
                }
            }
        }
        /*
         * we either finished a handshake or ignored the request, now try
         * again to obtain the (application) data we were asked for
         */
        goto start;
    }

    if (s->rlayer.d->alert_fragment_len >= DTLS1_AL_HEADER_LENGTH) {
        int alert_level = s->rlayer.d->alert_fragment[0];
        int alert_descr = s->rlayer.d->alert_fragment[1];

        s->rlayer.d->alert_fragment_len = 0;

        if (s->msg_callback)
            s->msg_callback(0, s->version, SSL3_RT_ALERT,
                            s->rlayer.d->alert_fragment, 2, s,
                            s->msg_callback_arg);

        if (s->info_callback != NULL)
            cb = s->info_callback;
        else if (s->ctx->info_callback != NULL)
            cb = s->ctx->info_callback;

        if (cb != NULL) {
            j = (alert_level << 8) | alert_descr;
            cb(s, SSL_CB_READ_ALERT, j);
        }

        if (alert_level == SSL3_AL_WARNING) {
            s->s3->warn_alert = alert_descr;
            if (alert_descr == SSL_AD_CLOSE_NOTIFY) {
#ifndef OPENSSL_NO_SCTP
                /*
                 * With SCTP and streams the socket may deliver app data
                 * after a close_notify alert. We have to check this first so
                 * that nothing gets discarded.
                 */
                if (BIO_dgram_is_sctp(SSL_get_rbio(s)) &&
                    BIO_dgram_sctp_msg_waiting(SSL_get_rbio(s))) {
                    s->d1->shutdown_received = 1;
                    s->rwstate = SSL_READING;
                    BIO_clear_retry_flags(SSL_get_rbio(s));
                    BIO_set_retry_read(SSL_get_rbio(s));
                    return -1;
                }
#endif
                s->shutdown |= SSL_RECEIVED_SHUTDOWN;
                return (0);
            }
#if 0
            /* XXX: this is a possible improvement in the future */
            /* now check if it's a missing record */
            if (alert_descr == DTLS1_AD_MISSING_HANDSHAKE_MESSAGE) {
                unsigned short seq;
                unsigned int frag_off;
                unsigned char *p = &(s->rlayer.d->alert_fragment[2]);

                n2s(p, seq);
                n2l3(p, frag_off);

                dtls1_retransmit_message(s,
                                         dtls1_get_queue_priority
                                         (frag->msg_header.seq, 0), frag_off,
                                         &found);
                if (!found && SSL_in_init(s)) {
                    /*
                     * fprintf( stderr,"in init = %d\n", SSL_in_init(s));
                     */
                    /*
                     * requested a message not yet sent, send an alert
                     * ourselves
                     */
                    ssl3_send_alert(s, SSL3_AL_WARNING,
                                    DTLS1_AD_MISSING_HANDSHAKE_MESSAGE);
                }
            }
#endif
        } else if (alert_level == SSL3_AL_FATAL) {
            char tmp[16];

            s->rwstate = SSL_NOTHING;
            s->s3->fatal_alert = alert_descr;
            SSLerr(SSL_F_DTLS1_READ_BYTES,
                   SSL_AD_REASON_OFFSET + alert_descr);
            BIO_snprintf(tmp, sizeof tmp, "%d", alert_descr);
            ERR_add_error_data(2, "SSL alert number ", tmp);
            s->shutdown |= SSL_RECEIVED_SHUTDOWN;
            SSL_CTX_remove_session(s->ctx, s->session);
            return (0);
        } else {
            al = SSL_AD_ILLEGAL_PARAMETER;
            SSLerr(SSL_F_DTLS1_READ_BYTES, SSL_R_UNKNOWN_ALERT_TYPE);
            goto f_err;
        }

        goto start;
    }

    if (s->shutdown & SSL_SENT_SHUTDOWN) { /* but we have not received a
                                            * shutdown */
        s->rwstate = SSL_NOTHING;
        SSL3_RECORD_set_length(rr, 0);
        return (0);
    }

    if (SSL3_RECORD_get_type(rr) == SSL3_RT_CHANGE_CIPHER_SPEC) {
        struct ccs_header_st ccs_hdr;
        unsigned int ccs_hdr_len = DTLS1_CCS_HEADER_LENGTH;

        dtls1_get_ccs_header(SSL3_RECORD_get_data(rr), &ccs_hdr);

        if (s->version == DTLS1_BAD_VER)
            ccs_hdr_len = 3;

        /*
         * 'Change Cipher Spec' is just a single byte, so we know exactly
         * what the record payload has to look like
         */
        /* XDTLS: check that epoch is consistent */
        if ((SSL3_RECORD_get_length(rr) != ccs_hdr_len)
                || (SSL3_RECORD_get_off(rr) != 0)
                || (SSL3_RECORD_get_data(rr)[0] != SSL3_MT_CCS)) {
            i = SSL_AD_ILLEGAL_PARAMETER;
            SSLerr(SSL_F_DTLS1_READ_BYTES, SSL_R_BAD_CHANGE_CIPHER_SPEC);
            goto err;
        }

        SSL3_RECORD_set_length(rr, 0);

        if (s->msg_callback)
            s->msg_callback(0, s->version, SSL3_RT_CHANGE_CIPHER_SPEC,
                SSL3_RECORD_get_data(rr), 1, s, s->msg_callback_arg);

        /*
         * We can't process a CCS now, because previous handshake messages
         * are still missing, so just drop it.
         */
        if (!s->d1->change_cipher_spec_ok) {
            goto start;
        }

        s->d1->change_cipher_spec_ok = 0;

        s->s3->change_cipher_spec = 1;
        if (!ssl3_do_change_cipher_spec(s))
            goto err;

        /* do this whenever CCS is processed */
        dtls1_reset_seq_numbers(s, SSL3_CC_READ);

        if (s->version == DTLS1_BAD_VER)
            s->d1->handshake_read_seq++;

#ifndef OPENSSL_NO_SCTP
        /*
         * Remember that a CCS has been received, so that an old key of
         * SCTP-Auth can be deleted when a CCS is sent. Will be ignored if no
         * SCTP is used
         */
        BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_AUTH_CCS_RCVD, 1, NULL);
#endif

        goto start;
    }

    /*
     * Unexpected handshake message (Client Hello, or protocol violation)
     */
    if ((s->rlayer.d->handshake_fragment_len >= DTLS1_HM_HEADER_LENGTH) &&
        !s->in_handshake) {
        struct hm_header_st msg_hdr;

        /* this may just be a stale retransmit */
        dtls1_get_message_header(rr->data, &msg_hdr);
        if (SSL3_RECORD_get_epoch(rr) != s->rlayer.d->r_epoch) {
            SSL3_RECORD_set_length(rr, 0);
            goto start;
        }

        /*
         * If we are server, we may have a repeated FINISHED of the client
         * here, then retransmit our CCS and FINISHED.
         */
        if (msg_hdr.type == SSL3_MT_FINISHED) {
            if (dtls1_check_timeout_num(s) < 0)
                return -1;

            dtls1_retransmit_buffered_messages(s);
            SSL3_RECORD_set_length(rr, 0);
            goto start;
        }

        if (((s->state & SSL_ST_MASK) == SSL_ST_OK) &&
            !(s->s3->flags & SSL3_FLAGS_NO_RENEGOTIATE_CIPHERS)) {
            s->state = s->server ? SSL_ST_ACCEPT : SSL_ST_CONNECT;
            s->renegotiate = 1;
            s->new_session = 1;
        }
        i = s->handshake_func(s);
        if (i < 0)
            return (i);
        if (i == 0) {
            SSLerr(SSL_F_DTLS1_READ_BYTES, SSL_R_SSL_HANDSHAKE_FAILURE);
            return (-1);
        }

        if (!(s->mode & SSL_MODE_AUTO_RETRY)) {
            if (SSL3_BUFFER_get_left(&s->rlayer.rbuf) == 0) {
                /* no read-ahead left? */
                BIO *bio;
                /*
                 * In the case where we try to read application data, but we
                 * trigger an SSL handshake, we return -1 with the retry
                 * option set.  Otherwise renegotiation may cause nasty
                 * problems in the blocking world
                 */
                s->rwstate = SSL_READING;
                bio = SSL_get_rbio(s);
                BIO_clear_retry_flags(bio);
                BIO_set_retry_read(bio);
                return (-1);
            }
        }
        goto start;
    }

    switch (SSL3_RECORD_get_type(rr)) {
    default:
        /* TLS just ignores unknown message types */
        if (s->version == TLS1_VERSION) {
            SSL3_RECORD_set_length(rr, 0);
            goto start;
        }
        al = SSL_AD_UNEXPECTED_MESSAGE;
        SSLerr(SSL_F_DTLS1_READ_BYTES, SSL_R_UNEXPECTED_RECORD);
        goto f_err;
    case SSL3_RT_CHANGE_CIPHER_SPEC:
    case SSL3_RT_ALERT:
    case SSL3_RT_HANDSHAKE:
        /*
         * we already handled all of these, with the possible exception of
         * SSL3_RT_HANDSHAKE when s->in_handshake is set, but that should not
         * happen when type != rr->type
         */
        al = SSL_AD_UNEXPECTED_MESSAGE;
        SSLerr(SSL_F_DTLS1_READ_BYTES, ERR_R_INTERNAL_ERROR);
        goto f_err;
    case SSL3_RT_APPLICATION_DATA:
        /*
         * At this point, we were expecting handshake data, but have
         * application data.  If the library was running inside ssl3_read()
         * (i.e. in_read_app_data is set) and it makes sense to read
         * application data at this point (session renegotiation not yet
         * started), we will indulge it.
         */
        if (s->s3->in_read_app_data &&
            (s->s3->total_renegotiations != 0) &&
            (((s->state & SSL_ST_CONNECT) &&
              (s->state >= SSL3_ST_CW_CLNT_HELLO_A) &&
              (s->state <= SSL3_ST_CR_SRVR_HELLO_A)
             ) || ((s->state & SSL_ST_ACCEPT) &&
                   (s->state <= SSL3_ST_SW_HELLO_REQ_A) &&
                   (s->state >= SSL3_ST_SR_CLNT_HELLO_A)
             )
            )) {
            s->s3->in_read_app_data = 2;
            return (-1);
        } else {
            al = SSL_AD_UNEXPECTED_MESSAGE;
            SSLerr(SSL_F_DTLS1_READ_BYTES, SSL_R_UNEXPECTED_RECORD);
            goto f_err;
        }
    }
    /* not reached */

 f_err:
    ssl3_send_alert(s, SSL3_AL_FATAL, al);
 err:
    return (-1);
}