zap_client.cpp

/* SPDX-License-Identifier: MPL-2.0 */

#include "precompiled.hpp"

#include "zap_client.hpp"
#include "msg.hpp"
#include "session_base.hpp"

namespace zmq
{
const char zap_version[] = "1.0";
const size_t zap_version_len = sizeof (zap_version) - 1;

const char id[] = "1";
const size_t id_len = sizeof (id) - 1;

zap_client_t::zap_client_t (session_base_t *const session_,
                            const std::string &peer_address_,
                            const options_t &options_) :
    mechanism_base_t (session_, options_), peer_address (peer_address_)
{
}

void zap_client_t::send_zap_request (const char *mechanism_,
                                     size_t mechanism_length_,
                                     const uint8_t *credentials_,
                                     size_t credentials_size_)
{
    send_zap_request (mechanism_, mechanism_length_, &credentials_,
                      &credentials_size_, 1);
}

void zap_client_t::send_zap_request (const char *mechanism_,
                                     size_t mechanism_length_,
                                     const uint8_t **credentials_,
                                     size_t *credentials_sizes_,
                                     size_t credentials_count_)
{
    // write_zap_msg cannot fail. It could only fail if the HWM was exceeded,
    // but on the ZAP socket, the HWM is disabled.

    int rc;
    msg_t msg;

    //  Address delimiter frame
    rc = msg.init ();
    errno_assert (rc == 0);
    msg.set_flags (msg_t::more);
    rc = session->write_zap_msg (&msg);
    errno_assert (rc == 0);

    //  Version frame
    rc = msg.init_size (zap_version_len);
    errno_assert (rc == 0);
    memcpy (msg.data (), zap_version, zap_version_len);
    msg.set_flags (msg_t::more);
    rc = session->write_zap_msg (&msg);
    errno_assert (rc == 0);

    //  Request ID frame
    rc = msg.init_size (id_len);
    errno_assert (rc == 0);
    memcpy (msg.data (), id, id_len);
    msg.set_flags (msg_t::more);
    rc = session->write_zap_msg (&msg);
    errno_assert (rc == 0);

    //  Domain frame
    rc = msg.init_size (options.zap_domain.length ());
    errno_assert (rc == 0);
    memcpy (msg.data (), options.zap_domain.c_str (),
            options.zap_domain.length ());
    msg.set_flags (msg_t::more);
    rc = session->write_zap_msg (&msg);
    errno_assert (rc == 0);

    //  Address frame
    rc = msg.init_size (peer_address.length ());
    errno_assert (rc == 0);
    memcpy (msg.data (), peer_address.c_str (), peer_address.length ());
    msg.set_flags (msg_t::more);
    rc = session->write_zap_msg (&msg);
    errno_assert (rc == 0);

    //  Routing id frame
    rc = msg.init_size (options.routing_id_size);
    errno_assert (rc == 0);
    memcpy (msg.data (), options.routing_id, options.routing_id_size);
    msg.set_flags (msg_t::more);
    rc = session->write_zap_msg (&msg);
    errno_assert (rc == 0);

    //  Mechanism frame
    rc = msg.init_size (mechanism_length_);
    errno_assert (rc == 0);
    memcpy (msg.data (), mechanism_, mechanism_length_);
    if (credentials_count_)
        msg.set_flags (msg_t::more);
    rc = session->write_zap_msg (&msg);
    errno_assert (rc == 0);

    //  Credentials frames
    for (size_t i = 0; i < credentials_count_; ++i) {
        rc = msg.init_size (credentials_sizes_[i]);
        errno_assert (rc == 0);
        if (i < credentials_count_ - 1)
            msg.set_flags (msg_t::more);
        memcpy (msg.data (), credentials_[i], credentials_sizes_[i]);
        rc = session->write_zap_msg (&msg);
        errno_assert (rc == 0);
    }
}

int zap_client_t::receive_and_process_zap_reply ()
{
    int rc = 0;
    const size_t zap_reply_frame_count = 7;
    msg_t msg[zap_reply_frame_count];

    //  Initialize all reply frames
    for (size_t i = 0; i < zap_reply_frame_count; i++) {
        rc = msg[i].init ();
        errno_assert (rc == 0);
    }

    for (size_t i = 0; i < zap_reply_frame_count; i++) {
        rc = session->read_zap_msg (&msg[i]);
        if (rc == -1) {
            if (errno == EAGAIN) {
                return 1;
            }
            return close_and_return (msg, -1);
        }
        if ((msg[i].flags () & msg_t::more)
            == (i < zap_reply_frame_count - 1 ? 0 : msg_t::more)) {
            session->get_socket ()->event_handshake_failed_protocol (
              session->get_endpoint (), ZMQ_PROTOCOL_ERROR_ZAP_MALFORMED_REPLY);
            errno = EPROTO;
            return close_and_return (msg, -1);
        }
    }

    //  Address delimiter frame
    if (msg[0].size () > 0) {
        //  TODO can a ZAP handler produce such a message at all?
        session->get_socket ()->event_handshake_failed_protocol (
          session->get_endpoint (), ZMQ_PROTOCOL_ERROR_ZAP_UNSPECIFIED);
        errno = EPROTO;
        return close_and_return (msg, -1);
    }

    //  Version frame
    if (msg[1].size () != zap_version_len
        || memcmp (msg[1].data (), zap_version, zap_version_len)) {
        session->get_socket ()->event_handshake_failed_protocol (
          session->get_endpoint (), ZMQ_PROTOCOL_ERROR_ZAP_BAD_VERSION);
        errno = EPROTO;
        return close_and_return (msg, -1);
    }

    //  Request id frame
    if (msg[2].size () != id_len || memcmp (msg[2].data (), id, id_len)) {
        session->get_socket ()->event_handshake_failed_protocol (
          session->get_endpoint (), ZMQ_PROTOCOL_ERROR_ZAP_BAD_REQUEST_ID);
        errno = EPROTO;
        return close_and_return (msg, -1);
    }

    //  Status code frame, only 200, 300, 400 and 500 are valid status codes
    const char *status_code_data = static_cast<const char *> (msg[3].data ());
    if (msg[3].size () != 3 || status_code_data[0] < '2'
        || status_code_data[0] > '5' || status_code_data[1] != '0'
        || status_code_data[2] != '0') {
        session->get_socket ()->event_handshake_failed_protocol (
          session->get_endpoint (), ZMQ_PROTOCOL_ERROR_ZAP_INVALID_STATUS_CODE);
        errno = EPROTO;
        return close_and_return (msg, -1);
    }

    //  Save status code
    status_code.assign (static_cast<char *> (msg[3].data ()), 3);

    //  Save user id
    set_user_id (msg[5].data (), msg[5].size ());

    //  Process metadata frame
    rc = parse_metadata (static_cast<const unsigned char *> (msg[6].data ()),
                         msg[6].size (), true);

    if (rc != 0) {
        session->get_socket ()->event_handshake_failed_protocol (
          session->get_endpoint (), ZMQ_PROTOCOL_ERROR_ZAP_INVALID_METADATA);
        errno = EPROTO;
        return close_and_return (msg, -1);
    }

    //  Close all reply frames
    for (size_t i = 0; i < zap_reply_frame_count; i++) {
        const int rc2 = msg[i].close ();
        errno_assert (rc2 == 0);
    }

    handle_zap_status_code ();

    return 0;
}

void zap_client_t::handle_zap_status_code ()
{
    //  we can assume here that status_code is a valid ZAP status code,
    //  i.e. 200, 300, 400 or 500
    int status_code_numeric = 0;
    switch (status_code[0]) {
        case '2':
            return;
        case '3':
            status_code_numeric = 300;
            break;
        case '4':
            status_code_numeric = 400;
            break;
        case '5':
            status_code_numeric = 500;
            break;
    }

    session->get_socket ()->event_handshake_failed_auth (
      session->get_endpoint (), status_code_numeric);
}

zap_client_common_handshake_t::zap_client_common_handshake_t (
  session_base_t *const session_,
  const std::string &peer_address_,
  const options_t &options_,
  state_t zap_reply_ok_state_) :
    mechanism_base_t (session_, options_),
    zap_client_t (session_, peer_address_, options_),
    state (waiting_for_hello),
    _zap_reply_ok_state (zap_reply_ok_state_)
{
}

zmq::mechanism_t::status_t zap_client_common_handshake_t::status () const
{
    if (state == ready)
        return mechanism_t::ready;
    if (state == error_sent)
        return mechanism_t::error;

    return mechanism_t::handshaking;
}

int zap_client_common_handshake_t::zap_msg_available ()
{
    zmq_assert (state == waiting_for_zap_reply);
    return receive_and_process_zap_reply () == -1 ? -1 : 0;
}

void zap_client_common_handshake_t::handle_zap_status_code ()
{
    zap_client_t::handle_zap_status_code ();

    //  we can assume here that status_code is a valid ZAP status code,
    //  i.e. 200, 300, 400 or 500
    switch (status_code[0]) {
        case '2':
            state = _zap_reply_ok_state;
            break;
        case '3':
            //  a 300 error code (temporary failure)
            //  should NOT result in an ERROR message, but instead the
            //  client should be silently disconnected (see CURVEZMQ RFC)
            //  therefore, go immediately to state error_sent
            state = error_sent;
            break;
        default:
            state = sending_error;
    }
}

int zap_client_common_handshake_t::receive_and_process_zap_reply ()
{
    zmq_assert (state == waiting_for_zap_reply);
    return zap_client_t::receive_and_process_zap_reply ();
}
}