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/* Copyright (C) 2002-2005 RealVNC Ltd. All Rights Reserved.
* Copyright (C) 2005 Martin Koegler
* Copyright (C) 2010 TigerVNC Team
* Copyright (C) 2012-2025 Pierre Ossman for Cendio AB
*
* 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
#include <core/Exception.h>
#include <core/LogWriter.h>
#include <rdr/InStream.h>
#include <rdr/OutStream.h>
#include <rdr/TLSException.h>
#include <rdr/TLSSocket.h>
#include <errno.h>
#ifdef HAVE_GNUTLS
using namespace rdr;
static core::LogWriter vlog("TLSSocket");
TLSSocket::TLSSocket(InStream* in_, OutStream* out_,
gnutls_session_t session_)
: session(session_), in(in_), out(out_), tlsin(this), tlsout(this)
{
gnutls_transport_set_pull_function(
session, [](gnutls_transport_ptr_t sock, void* data, size_t size) {
return ((TLSSocket*)sock)->pull(data, size);
});
gnutls_transport_set_push_function(
session, [](gnutls_transport_ptr_t sock, const void* data, size_t size) {
return ((TLSSocket*)sock)->push(data, size);
});
gnutls_transport_set_ptr(session, this);
}
TLSSocket::~TLSSocket()
{
gnutls_transport_set_pull_function(session, nullptr);
gnutls_transport_set_push_function(session, nullptr);
gnutls_transport_set_ptr(session, nullptr);
}
bool TLSSocket::handshake()
{
int err;
err = gnutls_handshake(session);
if (err != GNUTLS_E_SUCCESS) {
gnutls_alert_description_t alert;
const char* msg;
if ((err == GNUTLS_E_PULL_ERROR) || (err == GNUTLS_E_PUSH_ERROR))
std::rethrow_exception(saved_exception);
alert = gnutls_alert_get(session);
msg = nullptr;
if ((err == GNUTLS_E_WARNING_ALERT_RECEIVED) ||
(err == GNUTLS_E_FATAL_ALERT_RECEIVED))
msg = gnutls_alert_get_name(alert);
if (msg == nullptr)
msg = gnutls_strerror(err);
if (!gnutls_error_is_fatal(err)) {
vlog.debug("Deferring completion of TLS handshake: %s", msg);
return false;
}
vlog.error("TLS Handshake failed: %s\n", msg);
gnutls_alert_send_appropriate(session, err);
throw rdr::tls_error("TLS Handshake failed", err, alert);
}
return true;
}
void TLSSocket::shutdown()
{
int ret;
try {
if (tlsout.hasBufferedData()) {
tlsout.cork(false);
tlsout.flush();
if (tlsout.hasBufferedData())
vlog.error("Failed to flush remaining socket data on close");
}
} catch (std::exception& e) {
vlog.error("Failed to flush remaining socket data on close: %s", e.what());
}
// FIXME: We can't currently wait for the response, so we only send
// our close and hope for the best
ret = gnutls_bye(session, GNUTLS_SHUT_WR);
if ((ret != GNUTLS_E_SUCCESS) && (ret != GNUTLS_E_INVALID_SESSION))
vlog.error("TLS shutdown failed: %s", gnutls_strerror(ret));
}
size_t TLSSocket::readTLS(uint8_t* buf, size_t len)
{
int n;
while (true) {
streamEmpty = false;
n = gnutls_record_recv(session, (void *) buf, len);
if (n == GNUTLS_E_INTERRUPTED || n == GNUTLS_E_AGAIN) {
// GnuTLS returns GNUTLS_E_AGAIN for a bunch of other scenarios
// other than the pull function returning EAGAIN, so we have to
// double check that the underlying stream really is empty
if (!streamEmpty)
continue;
else
return 0;
}
break;
};
if (n == GNUTLS_E_PULL_ERROR)
std::rethrow_exception(saved_exception);
if (n < 0) {
gnutls_alert_send_appropriate(session, n);
throw tls_error("readTLS", n, gnutls_alert_get(session));
}
if (n == 0)
throw end_of_stream();
return n;
}
size_t TLSSocket::writeTLS(const uint8_t* data, size_t length)
{
int n;
n = gnutls_record_send(session, data, length);
if (n == GNUTLS_E_INTERRUPTED || n == GNUTLS_E_AGAIN)
return 0;
if (n == GNUTLS_E_PUSH_ERROR)
std::rethrow_exception(saved_exception);
if (n < 0) {
gnutls_alert_send_appropriate(session, n);
throw tls_error("writeTLS", n, gnutls_alert_get(session));
}
return n;
}
ssize_t TLSSocket::pull(void* data, size_t size)
{
streamEmpty = false;
saved_exception = nullptr;
try {
if (!in->hasData(1)) {
streamEmpty = true;
gnutls_transport_set_errno(session, EAGAIN);
return -1;
}
if (in->avail() < size)
size = in->avail();
in->readBytes((uint8_t*)data, size);
} catch (end_of_stream&) {
return 0;
} catch (std::exception& e) {
core::socket_error* se;
vlog.error("Failure reading TLS data: %s", e.what());
se = dynamic_cast<core::socket_error*>(&e);
if (se)
gnutls_transport_set_errno(session, se->err);
else
gnutls_transport_set_errno(session, EINVAL);
saved_exception = std::current_exception();
return -1;
}
return size;
}
ssize_t TLSSocket::push(const void* data, size_t size)
{
saved_exception = nullptr;
try {
out->writeBytes((const uint8_t*)data, size);
out->flush();
} catch (std::exception& e) {
core::socket_error* se;
vlog.error("Failure sending TLS data: %s", e.what());
se = dynamic_cast<core::socket_error*>(&e);
if (se)
gnutls_transport_set_errno(session, se->err);
else
gnutls_transport_set_errno(session, EINVAL);
saved_exception = std::current_exception();
return -1;
}
return size;
}
#endif
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