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 #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       return start_auth_sasl(vs);
  51 #endif /* CONFIG_VNC_SASL */
  52
  53     default: /* Should not be possible, but just in case */
  54        VNC_DEBUG("Reject subauth %d server bug\n", vs->vd->auth);
  55        vnc_write_u8(vs, 1);
  56        if (vs->minor >= 8) {
  57            static const char err[] = "Unsupported authentication type";
  58            vnc_write_u32(vs, sizeof(err));
  59            vnc_write(vs, err, sizeof(err));
  60        }
  61        vnc_client_error(vs);
  62     }
  63 }
  64
  65 static void vnc_tls_handshake_io(void *opaque);
  66
  67 static int vnc_start_vencrypt_handshake(struct VncState *vs) {
  68     int ret;
  69
  70     if ((ret = gnutls_handshake(vs->tls.session)) < 0) {
  71        if (!gnutls_error_is_fatal(ret)) {
  72            VNC_DEBUG("Handshake interrupted (blocking)\n");
  73            if (!gnutls_record_get_direction(vs->tls.session))
  74                qemu_set_fd_handler(vs->csock, vnc_tls_handshake_io, NULL, vs);
  75            else
  76                qemu_set_fd_handler(vs->csock, NULL, vnc_tls_handshake_io, vs);
  77            return 0;
  78        }
  79        VNC_DEBUG("Handshake failed %s\n", gnutls_strerror(ret));
  80        vnc_client_error(vs);
  81        return -1;
  82     }
  83
  84     if (vs->vd->tls.x509verify) {
  85         if (vnc_tls_validate_certificate(vs) < 0) {
  86             VNC_DEBUG("Client verification failed\n");
  87             vnc_client_error(vs);
  88             return -1;
  89         } else {
  90             VNC_DEBUG("Client verification passed\n");
  91         }
  92     }
  93
  94     VNC_DEBUG("Handshake done, switching to TLS data mode\n");
  95     vs->tls.wiremode = VNC_WIREMODE_TLS;
  96     qemu_set_fd_handler2(vs->csock, NULL, vnc_client_read, vnc_client_write, vs);
  97
  98     start_auth_vencrypt_subauth(vs);
  99
 100     return 0;
 101 }
 102
 103 static void vnc_tls_handshake_io(void *opaque) {
 104     struct VncState *vs = (struct VncState *)opaque;
 105
 106     VNC_DEBUG("Handshake IO continue\n");
 107     vnc_start_vencrypt_handshake(vs);
 108 }
 109
 110
 111
 112 #define NEED_X509_AUTH(vs)                              \
 113     ((vs)->vd->subauth == VNC_AUTH_VENCRYPT_X509NONE ||   \
 114      (vs)->vd->subauth == VNC_AUTH_VENCRYPT_X509VNC ||    \
 115      (vs)->vd->subauth == VNC_AUTH_VENCRYPT_X509PLAIN ||  \
 116      (vs)->vd->subauth == VNC_AUTH_VENCRYPT_X509SASL)
 117
 118
 119 static int protocol_client_vencrypt_auth(VncState *vs, uint8_t *data, size_t len)
 120 {
 121     int auth = read_u32(data, 0);
 122
 123     if (auth != vs->vd->subauth) {
 124         VNC_DEBUG("Rejecting auth %d\n", auth);
 125         vnc_write_u8(vs, 0); /* Reject auth */
 126         vnc_flush(vs);
 127         vnc_client_error(vs);
 128     } else {
 129         VNC_DEBUG("Accepting auth %d, setting up TLS for handshake\n", auth);
 130         vnc_write_u8(vs, 1); /* Accept auth */
 131         vnc_flush(vs);
 132
 133         if (vnc_tls_client_setup(vs, NEED_X509_AUTH(vs)) < 0) {
 134             VNC_DEBUG("Failed to setup TLS\n");
 135             return 0;
 136         }
 137
 138         VNC_DEBUG("Start TLS VeNCrypt handshake process\n");
 139         if (vnc_start_vencrypt_handshake(vs) < 0) {
 140             VNC_DEBUG("Failed to start TLS handshake\n");
 141             return 0;
 142         }
 143     }
 144     return 0;
 145 }
 146
 147 static int protocol_client_vencrypt_init(VncState *vs, uint8_t *data, size_t len)
 148 {
 149     if (data[0] != 0 ||
 150         data[1] != 2) {
 151         VNC_DEBUG("Unsupported VeNCrypt protocol %d.%d\n", (int)data[0], (int)data[1]);
 152         vnc_write_u8(vs, 1); /* Reject version */
 153         vnc_flush(vs);
 154         vnc_client_error(vs);
 155     } else {
 156         VNC_DEBUG("Sending allowed auth %d\n", vs->vd->subauth);
 157         vnc_write_u8(vs, 0); /* Accept version */
 158         vnc_write_u8(vs, 1); /* Number of sub-auths */
 159         vnc_write_u32(vs, vs->vd->subauth); /* The supported auth */
 160         vnc_flush(vs);
 161         vnc_read_when(vs, protocol_client_vencrypt_auth, 4);
 162     }
 163     return 0;
 164 }
 165
 166
 167 void start_auth_vencrypt(VncState *vs)
 168 {
 169     /* Send VeNCrypt version 0.2 */
 170     vnc_write_u8(vs, 0);
 171     vnc_write_u8(vs, 2);
 172
 173     vnc_read_when(vs, protocol_client_vencrypt_init, 2);
 174 }
 175