Пример #1
0
static int protocol_client_vencrypt_auth(VncState *vs, uint8_t *data, size_t len)
{
    int auth = read_u32(data, 0);

    if (auth != vs->vd->subauth) {
        VNC_DEBUG("Rejecting auth %d\n", auth);
        vnc_write_u8(vs, 0); /* Reject auth */
        vnc_flush(vs);
        vnc_client_error(vs);
    } else {
        VNC_DEBUG("Accepting auth %d, setting up TLS for handshake\n", auth);
        vnc_write_u8(vs, 1); /* Accept auth */
        vnc_flush(vs);

        if (vnc_tls_client_setup(vs, NEED_X509_AUTH(vs)) < 0) {
            VNC_DEBUG("Failed to setup TLS\n");
            return 0;
        }

        VNC_DEBUG("Start TLS VeNCrypt handshake process\n");
        if (vnc_start_vencrypt_handshake(vs) < 0) {
            VNC_DEBUG("Failed to start TLS handshake\n");
            return 0;
        }
    }
    return 0;
}
Пример #2
0
static int protocol_client_vencrypt_auth(VncState *vs, uint8_t *data, size_t len)
{
    int auth = read_u32(data, 0);

    trace_vnc_auth_vencrypt_subauth(vs, auth);
    if (auth != vs->subauth) {
        trace_vnc_auth_fail(vs, vs->auth, "Unsupported sub-auth version", "");
        vnc_write_u8(vs, 0); /* Reject auth */
        vnc_flush(vs);
        vnc_client_error(vs);
    } else {
        Error *err = NULL;
        QIOChannelTLS *tls;
        vnc_write_u8(vs, 1); /* Accept auth */
        vnc_flush(vs);

        if (vs->ioc_tag) {
            g_source_remove(vs->ioc_tag);
            vs->ioc_tag = 0;
        }

        tls = qio_channel_tls_new_server(
            vs->ioc,
            vs->vd->tlscreds,
            vs->vd->tlsauthzid,
            &err);
        if (!tls) {
            trace_vnc_auth_fail(vs, vs->auth, "TLS setup failed",
                                error_get_pretty(err));
            error_free(err);
            vnc_client_error(vs);
            return 0;
        }

        qio_channel_set_name(QIO_CHANNEL(tls), "vnc-server-tls");
        object_unref(OBJECT(vs->ioc));
        vs->ioc = QIO_CHANNEL(tls);
        trace_vnc_client_io_wrap(vs, vs->ioc, "tls");
        vs->tls = qio_channel_tls_get_session(tls);

        qio_channel_tls_handshake(tls,
                                  vnc_tls_handshake_done,
                                  vs,
                                  NULL,
                                  NULL);
    }
    return 0;
}
Пример #3
0
static int protocol_client_vencrypt_auth(VncState *vs, uint8_t *data, size_t len)
{
    int auth = read_u32(data, 0);

    if (auth != vs->subauth) {
        VNC_DEBUG("Rejecting auth %d\n", auth);
        vnc_write_u8(vs, 0); /* Reject auth */
        vnc_flush(vs);
        vnc_client_error(vs);
    } else {
        Error *err = NULL;
        QIOChannelTLS *tls;
        VNC_DEBUG("Accepting auth %d, setting up TLS for handshake\n", auth);
        vnc_write_u8(vs, 1); /* Accept auth */
        vnc_flush(vs);

        if (vs->ioc_tag) {
            g_source_remove(vs->ioc_tag);
            vs->ioc_tag = 0;
        }

        tls = qio_channel_tls_new_server(
            vs->ioc,
            vs->vd->tlscreds,
            vs->vd->tlsaclname,
            &err);
        if (!tls) {
            VNC_DEBUG("Failed to setup TLS %s\n", error_get_pretty(err));
            error_free(err);
            vnc_client_error(vs);
            return 0;
        }

        VNC_DEBUG("Start TLS VeNCrypt handshake process\n");
        object_unref(OBJECT(vs->ioc));
        vs->ioc = QIO_CHANNEL(tls);
        vs->tls = qio_channel_tls_get_session(tls);

        qio_channel_tls_handshake(tls,
                                  vnc_tls_handshake_done,
                                  vs,
                                  NULL);
    }
    return 0;
}
Пример #4
0
static int protocol_client_vencrypt_init(VncState *vs, uint8_t *data, size_t len)
{
    trace_vnc_auth_vencrypt_version(vs, (int)data[0], (int)data[1]);
    if (data[0] != 0 ||
        data[1] != 2) {
        trace_vnc_auth_fail(vs, vs->auth, "Unsupported version", "");
        vnc_write_u8(vs, 1); /* Reject version */
        vnc_flush(vs);
        vnc_client_error(vs);
    } else {
        vnc_write_u8(vs, 0); /* Accept version */
        vnc_write_u8(vs, 1); /* Number of sub-auths */
        vnc_write_u32(vs, vs->subauth); /* The supported auth */
        vnc_flush(vs);
        vnc_read_when(vs, protocol_client_vencrypt_auth, 4);
    }
    return 0;
}
Пример #5
0
static int protocol_client_vencrypt_init(VncState *vs, uint8_t *data, size_t len)
{
    if (data[0] != 0 ||
        data[1] != 2) {
        VNC_DEBUG("Unsupported VeNCrypt protocol %d.%d\n", (int)data[0], (int)data[1]);
        vnc_write_u8(vs, 1); /* Reject version */
        vnc_flush(vs);
        vnc_client_error(vs);
    } else {
        VNC_DEBUG("Sending allowed auth %d\n", vs->subauth);
        vnc_write_u8(vs, 0); /* Accept version */
        vnc_write_u8(vs, 1); /* Number of sub-auths */
        vnc_write_u32(vs, vs->subauth); /* The supported auth */
        vnc_flush(vs);
        vnc_read_when(vs, protocol_client_vencrypt_auth, 4);
    }
    return 0;
}
Пример #6
0
void start_auth_sasl(VncState *vs)
{
    const char *mechlist = NULL;
    sasl_security_properties_t secprops;
    int err;
    char *localAddr, *remoteAddr;
    int mechlistlen;

    VNC_DEBUG("Initialize SASL auth %p\n", vs->ioc);

    /* Get local & remote client addresses in form  IPADDR;PORT */
    localAddr = vnc_socket_ip_addr_string(vs->sioc, true, NULL);
    if (!localAddr) {
        goto authabort;
    }

    remoteAddr = vnc_socket_ip_addr_string(vs->sioc, false, NULL);
    if (!remoteAddr) {
        g_free(localAddr);
        goto authabort;
    }

    err = sasl_server_new("vnc",
                          NULL, /* FQDN - just delegates to gethostname */
                          NULL, /* User realm */
                          localAddr,
                          remoteAddr,
                          NULL, /* Callbacks, not needed */
                          SASL_SUCCESS_DATA,
                          &vs->sasl.conn);
    g_free(localAddr);
    g_free(remoteAddr);
    localAddr = remoteAddr = NULL;

    if (err != SASL_OK) {
        VNC_DEBUG("sasl context setup failed %d (%s)",
                  err, sasl_errstring(err, NULL, NULL));
        vs->sasl.conn = NULL;
        goto authabort;
    }

    /* Inform SASL that we've got an external SSF layer from TLS/x509 */
    if (vs->auth == VNC_AUTH_VENCRYPT &&
        vs->subauth == VNC_AUTH_VENCRYPT_X509SASL) {
        Error *local_err = NULL;
        int keysize;
        sasl_ssf_t ssf;

        keysize = qcrypto_tls_session_get_key_size(vs->tls,
                                                   &local_err);
        if (keysize < 0) {
            VNC_DEBUG("cannot TLS get cipher size: %s\n",
                      error_get_pretty(local_err));
            error_free(local_err);
            sasl_dispose(&vs->sasl.conn);
            vs->sasl.conn = NULL;
            goto authabort;
        }
        ssf = keysize * CHAR_BIT; /* tls key size is bytes, sasl wants bits */

        err = sasl_setprop(vs->sasl.conn, SASL_SSF_EXTERNAL, &ssf);
        if (err != SASL_OK) {
            VNC_DEBUG("cannot set SASL external SSF %d (%s)\n",
                      err, sasl_errstring(err, NULL, NULL));
            sasl_dispose(&vs->sasl.conn);
            vs->sasl.conn = NULL;
            goto authabort;
        }
    } else {
        vs->sasl.wantSSF = 1;
    }

    memset (&secprops, 0, sizeof secprops);
    /* Inform SASL that we've got an external SSF layer from TLS.
     *
     * Disable SSF, if using TLS+x509+SASL only. TLS without x509
     * is not sufficiently strong
     */
    if (vs->vd->is_unix ||
        (vs->auth == VNC_AUTH_VENCRYPT &&
         vs->subauth == VNC_AUTH_VENCRYPT_X509SASL)) {
        /* If we've got TLS or UNIX domain sock, we don't care about SSF */
        secprops.min_ssf = 0;
        secprops.max_ssf = 0;
        secprops.maxbufsize = 8192;
        secprops.security_flags = 0;
    } else {
        /* Plain TCP, better get an SSF layer */
        secprops.min_ssf = 56; /* Good enough to require kerberos */
        secprops.max_ssf = 100000; /* Arbitrary big number */
        secprops.maxbufsize = 8192;
        /* Forbid any anonymous or trivially crackable auth */
        secprops.security_flags =
            SASL_SEC_NOANONYMOUS | SASL_SEC_NOPLAINTEXT;
    }

    err = sasl_setprop(vs->sasl.conn, SASL_SEC_PROPS, &secprops);
    if (err != SASL_OK) {
        VNC_DEBUG("cannot set SASL security props %d (%s)\n",
                  err, sasl_errstring(err, NULL, NULL));
        sasl_dispose(&vs->sasl.conn);
        vs->sasl.conn = NULL;
        goto authabort;
    }

    err = sasl_listmech(vs->sasl.conn,
                        NULL, /* Don't need to set user */
                        "", /* Prefix */
                        ",", /* Separator */
                        "", /* Suffix */
                        &mechlist,
                        NULL,
                        NULL);
    if (err != SASL_OK) {
        VNC_DEBUG("cannot list SASL mechanisms %d (%s)\n",
                  err, sasl_errdetail(vs->sasl.conn));
        sasl_dispose(&vs->sasl.conn);
        vs->sasl.conn = NULL;
        goto authabort;
    }
    VNC_DEBUG("Available mechanisms for client: '%s'\n", mechlist);

    vs->sasl.mechlist = g_strdup(mechlist);
    mechlistlen = strlen(mechlist);
    vnc_write_u32(vs, mechlistlen);
    vnc_write(vs, mechlist, mechlistlen);
    vnc_flush(vs);

    VNC_DEBUG("Wait for client mechname length\n");
    vnc_read_when(vs, protocol_client_auth_sasl_mechname_len, 4);

    return;

 authabort:
    vnc_client_error(vs);
}
Пример #7
0
static int protocol_client_auth_sasl_start(VncState *vs, uint8_t *data, size_t len)
{
    uint32_t datalen = len;
    const char *serverout;
    unsigned int serveroutlen;
    int err;
    char *clientdata = NULL;

    /* NB, distinction of NULL vs "" is *critical* in SASL */
    if (datalen) {
        clientdata = (char*)data;
        clientdata[datalen-1] = '\0'; /* Should be on wire, but make sure */
        datalen--; /* Don't count NULL byte when passing to _start() */
    }

    VNC_DEBUG("Start SASL auth with mechanism %s. Data %p (%d bytes)\n",
              vs->sasl.mechlist, clientdata, datalen);
    err = sasl_server_start(vs->sasl.conn,
                            vs->sasl.mechlist,
                            clientdata,
                            datalen,
                            &serverout,
                            &serveroutlen);
    if (err != SASL_OK &&
        err != SASL_CONTINUE) {
        VNC_DEBUG("sasl start failed %d (%s)\n",
                  err, sasl_errdetail(vs->sasl.conn));
        sasl_dispose(&vs->sasl.conn);
        vs->sasl.conn = NULL;
        goto authabort;
    }
    if (serveroutlen > SASL_DATA_MAX_LEN) {
        VNC_DEBUG("sasl start reply data too long %d\n",
                  serveroutlen);
        sasl_dispose(&vs->sasl.conn);
        vs->sasl.conn = NULL;
        goto authabort;
    }

    VNC_DEBUG("SASL return data %d bytes, nil; %d\n",
              serveroutlen, serverout ? 0 : 1);

    if (serveroutlen) {
        vnc_write_u32(vs, serveroutlen + 1);
        vnc_write(vs, serverout, serveroutlen + 1);
    } else {
        vnc_write_u32(vs, 0);
    }

    /* Whether auth is complete */
    vnc_write_u8(vs, err == SASL_CONTINUE ? 0 : 1);

    if (err == SASL_CONTINUE) {
        VNC_DEBUG("%s", "Authentication must continue\n");
        /* Wait for step length */
        vnc_read_when(vs, protocol_client_auth_sasl_step_len, 4);
    } else {
        if (!vnc_auth_sasl_check_ssf(vs)) {
            VNC_DEBUG("Authentication rejected for weak SSF %p\n", vs->ioc);
            goto authreject;
        }

        /* Check username whitelist ACL */
        if (vnc_auth_sasl_check_access(vs) < 0) {
            VNC_DEBUG("Authentication rejected for ACL %p\n", vs->ioc);
            goto authreject;
        }

        VNC_DEBUG("Authentication successful %p\n", vs->ioc);
        vnc_write_u32(vs, 0); /* Accept auth */
        start_client_init(vs);
    }

    return 0;

 authreject:
    vnc_write_u32(vs, 1); /* Reject auth */
    vnc_write_u32(vs, sizeof("Authentication failed"));
    vnc_write(vs, "Authentication failed", sizeof("Authentication failed"));
    vnc_flush(vs);
    vnc_client_error(vs);
    return -1;

 authabort:
    vnc_client_error(vs);
    return -1;
}