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 void vnc_tls_handshake_io(void *opaque);
  67
  68 static int vnc_start_vencrypt_handshake(VncState *vs)
  69 {
  70     int ret;
  71
  72     if ((ret = gnutls_handshake(vs->tls.session)) < 0) {
  73        if (!gnutls_error_is_fatal(ret)) {
  74            VNC_DEBUG("Handshake interrupted (blocking)\n");
  75            if (!gnutls_record_get_direction(vs->tls.session))
  76                qemu_set_fd_handler(vs->csock, vnc_tls_handshake_io, NULL, vs);
  77            else
  78                qemu_set_fd_handler(vs->csock, NULL, vnc_tls_handshake_io, vs);
  79            return 0;
  80        }
  81        VNC_DEBUG("Handshake failed %s\n", gnutls_strerror(ret));
  82        vnc_client_error(vs);
  83        return -1;
  84     }
  85
  86     if (vs->vd->tls.x509verify) {
  87         if (vnc_tls_validate_certificate(vs) < 0) {
  88             VNC_DEBUG("Client verification failed\n");
  89             vnc_client_error(vs);
  90             return -1;
  91         } else {
  92             VNC_DEBUG("Client verification passed\n");
  93         }
  94     }
  95
  96     VNC_DEBUG("Handshake done, switching to TLS data mode\n");
  97     qemu_set_fd_handler(vs->csock, 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 {
 106     VncState *vs = (VncState *)opaque;
 107
 108     VNC_DEBUG("Handshake IO continue\n");
 109     vnc_start_vencrypt_handshake(vs);
 110 }
 111
 112
 113
 114 #define NEED_X509_AUTH(vs)                              \
 115     ((vs)->subauth == VNC_AUTH_VENCRYPT_X509NONE ||   \
 116      (vs)->subauth == VNC_AUTH_VENCRYPT_X509VNC ||    \
 117      (vs)->subauth == VNC_AUTH_VENCRYPT_X509PLAIN ||  \
 118      (vs)->subauth == VNC_AUTH_VENCRYPT_X509SASL)
 119
 120
 121 static int protocol_client_vencrypt_auth(VncState *vs, uint8_t *data, size_t len)
 122 {
 123     int auth = read_u32(data, 0);
 124
 125     if (auth != vs->subauth) {
 126         VNC_DEBUG("Rejecting auth %d\n", auth);
 127         vnc_write_u8(vs, 0); /* Reject auth */
 128         vnc_flush(vs);
 129         vnc_client_error(vs);
 130     } else {
 131         VNC_DEBUG("Accepting auth %d, setting up TLS for handshake\n", auth);
 132         vnc_write_u8(vs, 1); /* Accept auth */
 133         vnc_flush(vs);
 134
 135         if (vnc_tls_client_setup(vs, NEED_X509_AUTH(vs)) < 0) {
 136             VNC_DEBUG("Failed to setup TLS\n");
 137             return 0;
 138         }
 139
 140         VNC_DEBUG("Start TLS VeNCrypt handshake process\n");
 141         if (vnc_start_vencrypt_handshake(vs) < 0) {
 142             VNC_DEBUG("Failed to start TLS handshake\n");
 143             return 0;
 144         }
 145     }
 146     return 0;
 147 }
 148
 149 static int protocol_client_vencrypt_init(VncState *vs, uint8_t *data, size_t len)
 150 {
 151     if (data[0] != 0 ||
 152         data[1] != 2) {
 153         VNC_DEBUG("Unsupported VeNCrypt protocol %d.%d\n", (int)data[0], (int)data[1]);
 154         vnc_write_u8(vs, 1); /* Reject version */
 155         vnc_flush(vs);
 156         vnc_client_error(vs);
 157     } else {
 158         VNC_DEBUG("Sending allowed auth %d\n", vs->subauth);
 159         vnc_write_u8(vs, 0); /* Accept version */
 160         vnc_write_u8(vs, 1); /* Number of sub-auths */
 161         vnc_write_u32(vs, vs->subauth); /* The supported auth */
 162         vnc_flush(vs);
 163         vnc_read_when(vs, protocol_client_vencrypt_auth, 4);
 164     }
 165     return 0;
 166 }
 167
 168
 169 void start_auth_vencrypt(VncState *vs)
 170 {
 171     /* Send VeNCrypt version 0.2 */
 172     vnc_write_u8(vs, 0);
 173     vnc_write_u8(vs, 2);
 174
 175     vnc_read_when(vs, protocol_client_vencrypt_init, 2);
 176 }
 177