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
  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 void vnc_tls_handshake_io(void *opaque);
  67
  68 static int vnc_start_vencrypt_handshake(struct VncState *vs) {
  69     int ret;
  70
  71     if ((ret = gnutls_handshake(vs->tls.session)) < 0) {
  72        if (!gnutls_error_is_fatal(ret)) {
  73            VNC_DEBUG("Handshake interrupted (blocking)\n");
  74            if (!gnutls_record_get_direction(vs->tls.session))
  75                qemu_set_fd_handler(vs->csock, vnc_tls_handshake_io, NULL, vs);
  76            else
  77                qemu_set_fd_handler(vs->csock, NULL, vnc_tls_handshake_io, vs);
  78            return 0;
  79        }
  80        VNC_DEBUG("Handshake failed %s\n", gnutls_strerror(ret));
  81        vnc_client_error(vs);
  82        return -1;
  83     }
  84
  85     if (vs->vd->tls.x509verify) {
  86         if (vnc_tls_validate_certificate(vs) < 0) {
  87             VNC_DEBUG("Client verification failed\n");
  88             vnc_client_error(vs);
  89             return -1;
  90         } else {
  91             VNC_DEBUG("Client verification passed\n");
  92         }
  93     }
  94
  95     VNC_DEBUG("Handshake done, switching to TLS data mode\n");
  96     vs->tls.wiremode = VNC_WIREMODE_TLS;
  97     qemu_set_fd_handler2(vs->csock, NULL, vnc_client_read, vnc_client_write, vs);
  98
  99     start_auth_vencrypt_subauth(vs);
 100
 101     return 0;
 102 }
 103
 104 static void vnc_tls_handshake_io(void *opaque) {
 105     struct VncState *vs = (struct VncState *)opaque;
 106
 107     VNC_DEBUG("Handshake IO continue\n");
 108     vnc_start_vencrypt_handshake(vs);
 109 }
 110
 111
 112
 113 #define NEED_X509_AUTH(vs)                              \
 114     ((vs)->subauth == VNC_AUTH_VENCRYPT_X509NONE ||   \
 115      (vs)->subauth == VNC_AUTH_VENCRYPT_X509VNC ||    \
 116      (vs)->subauth == VNC_AUTH_VENCRYPT_X509PLAIN ||  \
 117      (vs)->subauth == VNC_AUTH_VENCRYPT_X509SASL)
 118
 119
 120 static int protocol_client_vencrypt_auth(VncState *vs, uint8_t *data, size_t len)
 121 {
 122     int auth = read_u32(data, 0);
 123
 124     if (auth != vs->subauth) {
 125         VNC_DEBUG("Rejecting auth %d\n", auth);
 126         vnc_write_u8(vs, 0); /* Reject auth */
 127         vnc_flush(vs);
 128         vnc_client_error(vs);
 129     } else {
 130         VNC_DEBUG("Accepting auth %d, setting up TLS for handshake\n", auth);
 131         vnc_write_u8(vs, 1); /* Accept auth */
 132         vnc_flush(vs);
 133
 134         if (vnc_tls_client_setup(vs, NEED_X509_AUTH(vs)) < 0) {
 135             VNC_DEBUG("Failed to setup TLS\n");
 136             return 0;
 137         }
 138
 139         VNC_DEBUG("Start TLS VeNCrypt handshake process\n");
 140         if (vnc_start_vencrypt_handshake(vs) < 0) {
 141             VNC_DEBUG("Failed to start TLS handshake\n");
 142             return 0;
 143         }
 144     }
 145     return 0;
 146 }
 147
 148 static int protocol_client_vencrypt_init(VncState *vs, uint8_t *data, size_t len)
 149 {
 150     if (data[0] != 0 ||
 151         data[1] != 2) {
 152         VNC_DEBUG("Unsupported VeNCrypt protocol %d.%d\n", (int)data[0], (int)data[1]);
 153         vnc_write_u8(vs, 1); /* Reject version */
 154         vnc_flush(vs);
 155         vnc_client_error(vs);
 156     } else {
 157         VNC_DEBUG("Sending allowed auth %d\n", vs->subauth);
 158         vnc_write_u8(vs, 0); /* Accept version */
 159         vnc_write_u8(vs, 1); /* Number of sub-auths */
 160         vnc_write_u32(vs, vs->subauth); /* The supported auth */
 161         vnc_flush(vs);
 162         vnc_read_when(vs, protocol_client_vencrypt_auth, 4);
 163     }
 164     return 0;
 165 }
 166
 167
 168 void start_auth_vencrypt(VncState *vs)
 169 {
 170     /* Send VeNCrypt version 0.2 */
 171     vnc_write_u8(vs, 0);
 172     vnc_write_u8(vs, 2);
 173
 174     vnc_read_when(vs, protocol_client_vencrypt_init, 2);
 175 }
 176