ui/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 #include "qemu/main-loop.h"
  29
  30 static void start_auth_vencrypt_subauth(VncState *vs)
  31 {
  32     switch (vs->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 #ifdef CONFIG_VNC_SASL
  47     case VNC_AUTH_VENCRYPT_TLSSASL:
  48     case VNC_AUTH_VENCRYPT_X509SASL:
  49       VNC_DEBUG("Start TLS auth SASL\n");
  50       start_auth_sasl(vs);
  51       break;
  52 #endif /* CONFIG_VNC_SASL */
  53
  54     default: /* Should not be possible, but just in case */
  55        VNC_DEBUG("Reject subauth %d server bug\n", vs->auth);
  56        vnc_write_u8(vs, 1);
  57        if (vs->minor >= 8) {
  58            static const char err[] = "Unsupported authentication type";
  59            vnc_write_u32(vs, sizeof(err));
  60            vnc_write(vs, err, sizeof(err));
  61        }
  62        vnc_client_error(vs);
  63     }
  64 }
  65
  66 static gboolean vnc_tls_handshake_io(QIOChannel *ioc,
  67                                      GIOCondition condition,
  68                                      void *opaque);
  69
  70 static int vnc_start_vencrypt_handshake(VncState *vs)
  71 {
  72     Error *err = NULL;
  73
  74     if (qcrypto_tls_session_handshake(vs->tls, &err) < 0) {
  75         goto error;
  76     }
  77
  78     switch (qcrypto_tls_session_get_handshake_status(vs->tls)) {
  79     case QCRYPTO_TLS_HANDSHAKE_COMPLETE:
  80         VNC_DEBUG("Handshake done, checking credentials\n");
  81         if (qcrypto_tls_session_check_credentials(vs->tls, &err) < 0) {
  82             goto error;
  83         }
  84         VNC_DEBUG("Client verification passed, starting TLS I/O\n");
  85         if (vs->ioc_tag) {
  86             g_source_remove(vs->ioc_tag);
  87         }
  88         vs->ioc_tag = qio_channel_add_watch(
  89             vs->ioc, G_IO_IN | G_IO_OUT, vnc_client_io, vs, NULL);
  90
  91         start_auth_vencrypt_subauth(vs);
  92         break;
  93
  94     case QCRYPTO_TLS_HANDSHAKE_RECVING:
  95         VNC_DEBUG("Handshake interrupted (blocking read)\n");
  96         if (vs->ioc_tag) {
  97             g_source_remove(vs->ioc_tag);
  98         }
  99         vs->ioc_tag = qio_channel_add_watch(
 100             vs->ioc, G_IO_IN, vnc_tls_handshake_io, vs, NULL);
 101         break;
 102
 103     case QCRYPTO_TLS_HANDSHAKE_SENDING:
 104         VNC_DEBUG("Handshake interrupted (blocking write)\n");
 105         if (vs->ioc_tag) {
 106             g_source_remove(vs->ioc_tag);
 107         }
 108         vs->ioc_tag = qio_channel_add_watch(
 109             vs->ioc, G_IO_OUT, vnc_tls_handshake_io, vs, NULL);
 110         break;
 111     }
 112
 113     return 0;
 114
 115  error:
 116     VNC_DEBUG("Handshake failed %s\n", error_get_pretty(err));
 117     error_free(err);
 118     vnc_client_error(vs);
 119     return -1;
 120 }
 121
 122 static gboolean vnc_tls_handshake_io(QIOChannel *ioc G_GNUC_UNUSED,
 123                                      GIOCondition condition G_GNUC_UNUSED,
 124                                      void *opaque)
 125 {
 126     VncState *vs = (VncState *)opaque;
 127
 128     VNC_DEBUG("Handshake IO continue\n");
 129     vnc_start_vencrypt_handshake(vs);
 130     return TRUE;
 131 }
 132
 133
 134 static int protocol_client_vencrypt_auth(VncState *vs, uint8_t *data, size_t len)
 135 {
 136     int auth = read_u32(data, 0);
 137
 138     if (auth != vs->subauth) {
 139         VNC_DEBUG("Rejecting auth %d\n", auth);
 140         vnc_write_u8(vs, 0); /* Reject auth */
 141         vnc_flush(vs);
 142         vnc_client_error(vs);
 143     } else {
 144         Error *err = NULL;
 145         VNC_DEBUG("Accepting auth %d, setting up TLS for handshake\n", auth);
 146         vnc_write_u8(vs, 1); /* Accept auth */
 147         vnc_flush(vs);
 148
 149         vs->tls = qcrypto_tls_session_new(vs->vd->tlscreds,
 150                                           NULL,
 151                                           vs->vd->tlsaclname,
 152                                           QCRYPTO_TLS_CREDS_ENDPOINT_SERVER,
 153                                           &err);
 154         if (!vs->tls) {
 155             VNC_DEBUG("Failed to setup TLS %s\n",
 156                       error_get_pretty(err));
 157             error_free(err);
 158             vnc_client_error(vs);
 159             return 0;
 160         }
 161
 162         qcrypto_tls_session_set_callbacks(vs->tls,
 163                                           vnc_tls_push,
 164                                           vnc_tls_pull,
 165                                           vs);
 166
 167         VNC_DEBUG("Start TLS VeNCrypt handshake process\n");
 168         if (vnc_start_vencrypt_handshake(vs) < 0) {
 169             VNC_DEBUG("Failed to start TLS handshake\n");
 170             return 0;
 171         }
 172     }
 173     return 0;
 174 }
 175
 176 static int protocol_client_vencrypt_init(VncState *vs, uint8_t *data, size_t len)
 177 {
 178     if (data[0] != 0 ||
 179         data[1] != 2) {
 180         VNC_DEBUG("Unsupported VeNCrypt protocol %d.%d\n", (int)data[0], (int)data[1]);
 181         vnc_write_u8(vs, 1); /* Reject version */
 182         vnc_flush(vs);
 183         vnc_client_error(vs);
 184     } else {
 185         VNC_DEBUG("Sending allowed auth %d\n", vs->subauth);
 186         vnc_write_u8(vs, 0); /* Accept version */
 187         vnc_write_u8(vs, 1); /* Number of sub-auths */
 188         vnc_write_u32(vs, vs->subauth); /* The supported auth */
 189         vnc_flush(vs);
 190         vnc_read_when(vs, protocol_client_vencrypt_auth, 4);
 191     }
 192     return 0;
 193 }
 194
 195
 196 void start_auth_vencrypt(VncState *vs)
 197 {
 198     /* Send VeNCrypt version 0.2 */
 199     vnc_write_u8(vs, 0);
 200     vnc_write_u8(vs, 2);
 201
 202     vnc_read_when(vs, protocol_client_vencrypt_init, 2);
 203 }
 204