vnc-auth-vencrypt.c

   1 /*
   2  * QEMU VNC display driver: VeNCrypt authentication setup
   3  *
   4  * Copyright (C) 2006 Anthony Liguori <anthony@codemonkey.ws>
   5  * Copyright (C) 2006 Fabrice Bellard
   6  * Copyright (C) 2009 Red Hat, Inc
   7  *
   8  * Permission is hereby granted, free of charge, to any person obtaining a copy
   9  * of this software and associated documentation files (the "Software"), to deal
  10  * in the Software without restriction, including without limitation the rights
  11  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  12  * copies of the Software, and to permit persons to whom the Software is
  13  * furnished to do so, subject to the following conditions:
  14  *
  15  * The above copyright notice and this permission notice shall be included in
  16  * all copies or substantial portions of the Software.
  17  *
  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  19  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  20  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  21  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  22  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  23  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  24  * THE SOFTWARE.
  25  */
  26
  27 #include "vnc.h"
  28
  29
  30 static void start_auth_vencrypt_subauth(VncState *vs)
  31 {
  32     switch (vs->vd->subauth) {
  33     case VNC_AUTH_VENCRYPT_TLSNONE:
  34     case VNC_AUTH_VENCRYPT_X509NONE:
  35        VNC_DEBUG("Accept TLS auth none\n");
  36        vnc_write_u32(vs, 0); /* Accept auth completion */
  37        start_client_init(vs);
  38        break;
  39
  40     case VNC_AUTH_VENCRYPT_TLSVNC:
  41     case VNC_AUTH_VENCRYPT_X509VNC:
  42        VNC_DEBUG("Start TLS auth VNC\n");
  43        start_auth_vnc(vs);
  44        break;
  45
  46     default: /* Should not be possible, but just in case */
  47        VNC_DEBUG("Reject auth %d\n", vs->vd->auth);
  48        vnc_write_u8(vs, 1);
  49        if (vs->minor >= 8) {
  50            static const char err[] = "Unsupported authentication type";
  51            vnc_write_u32(vs, sizeof(err));
  52            vnc_write(vs, err, sizeof(err));
  53        }
  54        vnc_client_error(vs);
  55     }
  56 }
  57
  58 static void vnc_tls_handshake_io(void *opaque);
  59
  60 static int vnc_start_vencrypt_handshake(struct VncState *vs) {
  61     int ret;
  62
  63     if ((ret = gnutls_handshake(vs->tls.session)) < 0) {
  64        if (!gnutls_error_is_fatal(ret)) {
  65            VNC_DEBUG("Handshake interrupted (blocking)\n");
  66            if (!gnutls_record_get_direction(vs->tls.session))
  67                qemu_set_fd_handler(vs->csock, vnc_tls_handshake_io, NULL, vs);
  68            else
  69                qemu_set_fd_handler(vs->csock, NULL, vnc_tls_handshake_io, vs);
  70            return 0;
  71        }
  72        VNC_DEBUG("Handshake failed %s\n", gnutls_strerror(ret));
  73        vnc_client_error(vs);
  74        return -1;
  75     }
  76
  77     if (vs->vd->tls.x509verify) {
  78         if (vnc_tls_validate_certificate(vs) < 0) {
  79             VNC_DEBUG("Client verification failed\n");
  80             vnc_client_error(vs);
  81             return -1;
  82         } else {
  83             VNC_DEBUG("Client verification passed\n");
  84         }
  85     }
  86
  87     VNC_DEBUG("Handshake done, switching to TLS data mode\n");
  88     vs->tls.wiremode = VNC_WIREMODE_TLS;
  89     qemu_set_fd_handler2(vs->csock, NULL, vnc_client_read, vnc_client_write, vs);
  90
  91     start_auth_vencrypt_subauth(vs);
  92
  93     return 0;
  94 }
  95
  96 static void vnc_tls_handshake_io(void *opaque) {
  97     struct VncState *vs = (struct VncState *)opaque;
  98
  99     VNC_DEBUG("Handshake IO continue\n");
 100     vnc_start_vencrypt_handshake(vs);
 101 }
 102
 103
 104
 105 #define NEED_X509_AUTH(vs)                            \
 106     ((vs)->vd->subauth == VNC_AUTH_VENCRYPT_X509NONE ||   \
 107      (vs)->vd->subauth == VNC_AUTH_VENCRYPT_X509VNC ||    \
 108      (vs)->vd->subauth == VNC_AUTH_VENCRYPT_X509PLAIN)
 109
 110
 111 static int protocol_client_vencrypt_auth(VncState *vs, uint8_t *data, size_t len)
 112 {
 113     int auth = read_u32(data, 0);
 114
 115     if (auth != vs->vd->subauth) {
 116         VNC_DEBUG("Rejecting auth %d\n", auth);
 117         vnc_write_u8(vs, 0); /* Reject auth */
 118         vnc_flush(vs);
 119         vnc_client_error(vs);
 120     } else {
 121         VNC_DEBUG("Accepting auth %d, setting up TLS for handshake\n", auth);
 122         vnc_write_u8(vs, 1); /* Accept auth */
 123         vnc_flush(vs);
 124
 125         if (vnc_tls_client_setup(vs, NEED_X509_AUTH(vs)) < 0) {
 126             VNC_DEBUG("Failed to setup TLS\n");
 127             return 0;
 128         }
 129
 130         VNC_DEBUG("Start TLS VeNCrypt handshake process\n");
 131         if (vnc_start_vencrypt_handshake(vs) < 0) {
 132             VNC_DEBUG("Failed to start TLS handshake\n");
 133             return 0;
 134         }
 135     }
 136     return 0;
 137 }
 138
 139 static int protocol_client_vencrypt_init(VncState *vs, uint8_t *data, size_t len)
 140 {
 141     if (data[0] != 0 ||
 142         data[1] != 2) {
 143         VNC_DEBUG("Unsupported VeNCrypt protocol %d.%d\n", (int)data[0], (int)data[1]);
 144         vnc_write_u8(vs, 1); /* Reject version */
 145         vnc_flush(vs);
 146         vnc_client_error(vs);
 147     } else {
 148         VNC_DEBUG("Sending allowed auth %d\n", vs->vd->subauth);
 149         vnc_write_u8(vs, 0); /* Accept version */
 150         vnc_write_u8(vs, 1); /* Number of sub-auths */
 151         vnc_write_u32(vs, vs->vd->subauth); /* The supported auth */
 152         vnc_flush(vs);
 153         vnc_read_when(vs, protocol_client_vencrypt_auth, 4);
 154     }
 155     return 0;
 156 }
 157
 158
 159 void start_auth_vencrypt(VncState *vs)
 160 {
 161     /* Send VeNCrypt version 0.2 */
 162     vnc_write_u8(vs, 0);
 163     vnc_write_u8(vs, 2);
 164
 165     vnc_read_when(vs, protocol_client_vencrypt_init, 2);
 166 }
 167