Archipelago » qemu

/*

 * QEMU VNC display driver: VeNCrypt authentication setup

 *

 * Copyright (C) 2006 Anthony Liguori <anthony@codemonkey.ws>

 * Copyright (C) 2006 Fabrice Bellard

 * Copyright (C) 2009 Red Hat, Inc

 *

 * Permission is hereby granted, free of charge, to any person obtaining a copy

 * of this software and associated documentation files (the "Software"), to deal

 * in the Software without restriction, including without limitation the rights

 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

 * copies of the Software, and to permit persons to whom the Software is

 * furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in

 * all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL

 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

 * THE SOFTWARE.

 */

#include "vnc.h"

static void start_auth_vencrypt_subauth(VncState *vs)

{

    switch (vs->subauth) {

    case VNC_AUTH_VENCRYPT_TLSNONE:

    case VNC_AUTH_VENCRYPT_X509NONE:

       VNC_DEBUG("Accept TLS auth none\n");

       vnc_write_u32(vs, 0); /* Accept auth completion */

       start_client_init(vs);

       break;

    case VNC_AUTH_VENCRYPT_TLSVNC:

    case VNC_AUTH_VENCRYPT_X509VNC:

       VNC_DEBUG("Start TLS auth VNC\n");

       start_auth_vnc(vs);

       break;

#ifdef CONFIG_VNC_SASL

    case VNC_AUTH_VENCRYPT_TLSSASL:

    case VNC_AUTH_VENCRYPT_X509SASL:

      VNC_DEBUG("Start TLS auth SASL\n");

      return start_auth_sasl(vs);

#endif /* CONFIG_VNC_SASL */

    default: /* Should not be possible, but just in case */

       VNC_DEBUG("Reject subauth %d server bug\n", vs->auth);

       vnc_write_u8(vs, 1);

       if (vs->minor >= 8) {

           static const char err[] = "Unsupported authentication type";

           vnc_write_u32(vs, sizeof(err));

           vnc_write(vs, err, sizeof(err));

       }

       vnc_client_error(vs);

    }

}

static void vnc_tls_handshake_io(void *opaque);

static int vnc_start_vencrypt_handshake(struct VncState *vs) {

    int ret;

    if ((ret = gnutls_handshake(vs->tls.session)) < 0) {

       if (!gnutls_error_is_fatal(ret)) {

           VNC_DEBUG("Handshake interrupted (blocking)\n");

           if (!gnutls_record_get_direction(vs->tls.session))

               qemu_set_fd_handler(vs->csock, vnc_tls_handshake_io, NULL, vs);

           else

               qemu_set_fd_handler(vs->csock, NULL, vnc_tls_handshake_io, vs);

           return 0;

       }

       VNC_DEBUG("Handshake failed %s\n", gnutls_strerror(ret));

       vnc_client_error(vs);

       return -1;

    }

    if (vs->vd->tls.x509verify) {

        if (vnc_tls_validate_certificate(vs) < 0) {

            VNC_DEBUG("Client verification failed\n");

            vnc_client_error(vs);

            return -1;

        } else {

            VNC_DEBUG("Client verification passed\n");

        }

    }

    VNC_DEBUG("Handshake done, switching to TLS data mode\n");

    vs->tls.wiremode = VNC_WIREMODE_TLS;

    qemu_set_fd_handler2(vs->csock, NULL, vnc_client_read, vnc_client_write, vs);

    start_auth_vencrypt_subauth(vs);

    return 0;

}

static void vnc_tls_handshake_io(void *opaque) {

    struct VncState *vs = (struct VncState *)opaque;

    VNC_DEBUG("Handshake IO continue\n");

    vnc_start_vencrypt_handshake(vs);

}

#define NEED_X509_AUTH(vs)                              \

    ((vs)->subauth == VNC_AUTH_VENCRYPT_X509NONE ||   \

     (vs)->subauth == VNC_AUTH_VENCRYPT_X509VNC ||    \

     (vs)->subauth == VNC_AUTH_VENCRYPT_X509PLAIN ||  \

     (vs)->subauth == VNC_AUTH_VENCRYPT_X509SASL)

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 {

        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;

}

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;

}

void start_auth_vencrypt(VncState *vs)

{

    /* Send VeNCrypt version 0.2 */

    vnc_write_u8(vs, 0);

    vnc_write_u8(vs, 2);

    vnc_read_when(vs, protocol_client_vencrypt_init, 2);

}