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/*
* Copyright (C) 2004 Red Hat Inc.
* Copyright (C) 2005 Martin Koegler
* Copyright (C) 2010 TigerVNC Team
*
* This is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this software; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
* USA.
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#ifndef HAVE_GNUTLS
#error "This header should not be compiled without HAVE_GNUTLS defined"
#endif
#include <rfb/CSecurityTLS.h>
#include <rfb/SSecurityVeNCrypt.h>
#include <rfb/CConnection.h>
#include <rfb/LogWriter.h>
#include <rfb/Exception.h>
#include <rdr/TLSInStream.h>
#include <rdr/TLSOutStream.h>
#include <gnutls/x509.h>
#define TLS_DEBUG
using namespace rfb;
StringParameter CSecurityTLS::x509ca("x509ca", "X509 CA certificate", "", ConfViewer);
StringParameter CSecurityTLS::x509crl("x509crl", "X509 CRL file", "", ConfViewer);
static LogWriter vlog("TLS");
#ifdef TLS_DEBUG
static void debug_log(int level, const char* str)
{
vlog.debug(str);
}
#endif
void CSecurityTLS::initGlobal()
{
static bool globalInitDone = false;
if (!globalInitDone) {
gnutls_global_init();
#ifdef TLS_DEBUG
gnutls_global_set_log_level(10);
gnutls_global_set_log_function(debug_log);
#endif
globalInitDone = true;
}
}
CSecurityTLS::CSecurityTLS(bool _anon) : session(0), anon_cred(0),
anon(_anon), fis(0), fos(0)
{
cafile = x509ca.getData();
crlfile = x509crl.getData();
}
void CSecurityTLS::shutdown()
{
if (session)
if (gnutls_bye(session, GNUTLS_SHUT_RDWR) != GNUTLS_E_SUCCESS)
throw Exception("gnutls_bye failed");
if (anon_cred) {
gnutls_anon_free_client_credentials(anon_cred);
anon_cred = 0;
}
if (cert_cred) {
gnutls_certificate_free_credentials(cert_cred);
cert_cred = 0;
}
if (session) {
gnutls_deinit(session);
session = 0;
gnutls_global_deinit();
}
}
CSecurityTLS::~CSecurityTLS()
{
shutdown();
if (fis)
delete fis;
if (fos)
delete fos;
delete[] cafile;
delete[] crlfile;
}
bool CSecurityTLS::processMsg(CConnection* cc)
{
rdr::InStream* is = cc->getInStream();
rdr::OutStream* os = cc->getOutStream();
client = cc;
initGlobal();
if (!session) {
if (!is->checkNoWait(1))
return false;
if (is->readU8() == 0)
return true;
if (gnutls_init(&session, GNUTLS_CLIENT) != GNUTLS_E_SUCCESS)
throw AuthFailureException("gnutls_init failed");
if (gnutls_set_default_priority(session) != GNUTLS_E_SUCCESS)
throw AuthFailureException("gnutls_set_default_priority failed");
setParam();
gnutls_transport_set_pull_function(session, rdr::gnutls_InStream_pull);
gnutls_transport_set_push_function(session, rdr::gnutls_OutStream_push);
gnutls_transport_set_ptr2(session,
(gnutls_transport_ptr) is,
(gnutls_transport_ptr) os);
}
int err;
err = gnutls_handshake(session);
if (err != GNUTLS_E_SUCCESS && !gnutls_error_is_fatal(err))
return false;
if (err != GNUTLS_E_SUCCESS) {
vlog.error("TLS Handshake failed: %s\n", gnutls_strerror (err));
shutdown();
throw AuthFailureException("TLS Handshake failed");
}
checkSession();
cc->setStreams(fis = new rdr::TLSInStream(is, session),
fos = new rdr::TLSOutStream(os, session));
return true;
}
void CSecurityTLS::setParam()
{
static const int kx_anon_priority[] = { GNUTLS_KX_ANON_DH, 0 };
static const int kx_priority[] = { GNUTLS_KX_DHE_DSS, GNUTLS_KX_RSA,
GNUTLS_KX_DHE_RSA, GNUTLS_KX_SRP, 0 };
if (anon) {
if (gnutls_kx_set_priority(session, kx_anon_priority) != GNUTLS_E_SUCCESS)
throw AuthFailureException("gnutls_kx_set_priority failed");
if (gnutls_anon_allocate_client_credentials(&anon_cred) != GNUTLS_E_SUCCESS)
throw AuthFailureException("gnutls_anon_allocate_client_credentials failed");
if (gnutls_credentials_set(session, GNUTLS_CRD_ANON, anon_cred) != GNUTLS_E_SUCCESS)
throw AuthFailureException("gnutls_credentials_set failed");
vlog.debug("Anonymous session has been set");
} else {
if (gnutls_kx_set_priority(session, kx_priority) != GNUTLS_E_SUCCESS)
throw AuthFailureException("gnutls_kx_set_priority failed");
if (gnutls_certificate_allocate_credentials(&cert_cred) != GNUTLS_E_SUCCESS)
throw AuthFailureException("gnutls_certificate_allocate_credentials failed");
if (*cafile && gnutls_certificate_set_x509_trust_file(cert_cred,cafile,GNUTLS_X509_FMT_PEM) < 0)
throw AuthFailureException("load of CA cert failed");
if (*crlfile && gnutls_certificate_set_x509_crl_file(cert_cred,crlfile,GNUTLS_X509_FMT_PEM) < 0)
throw AuthFailureException("load of CRL failed");
if (gnutls_credentials_set(session, GNUTLS_CRD_CERTIFICATE, cert_cred) != GNUTLS_E_SUCCESS)
throw AuthFailureException("gnutls_credentials_set failed");
vlog.debug("X509 session has been set");
}
}
void CSecurityTLS::checkSession()
{
int status;
const gnutls_datum *cert_list;
unsigned int cert_list_size = 0;
unsigned int i;
if (anon)
return;
if (gnutls_certificate_type_get(session) != GNUTLS_CRT_X509)
throw AuthFailureException("unsupported certificate type");
cert_list = gnutls_certificate_get_peers(session, &cert_list_size);
if (!cert_list_size)
throw AuthFailureException("unsupported certificate type");
status = gnutls_certificate_verify_peers(session);
if (status == GNUTLS_E_NO_CERTIFICATE_FOUND)
throw AuthFailureException("no certificate sent");
if (status < 0) {
vlog.error("X509 verify failed: %s\n", gnutls_strerror (status));
throw AuthFailureException("certificate verification failed");
}
if (status & GNUTLS_CERT_SIGNER_NOT_FOUND)
throw AuthFailureException("certificate issuer unknown");
if (status & GNUTLS_CERT_INVALID)
throw AuthFailureException("certificate not trusted");
for (i = 0; i < cert_list_size; i++) {
gnutls_x509_crt crt;
gnutls_x509_crt_init(&crt);
if (gnutls_x509_crt_import(crt, &cert_list[i],GNUTLS_X509_FMT_DER) < 0)
throw AuthFailureException("Decoding of certificate failed");
if (gnutls_x509_crt_check_hostname(crt, client->getServerName()) == 0) {
#if 0
throw AuthFailureException("Hostname mismatch"); /* Non-fatal for now... */
#endif
}
gnutls_x509_crt_deinit(crt);
}
}
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