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/*
This file is part of libmicrohttpd
Copyright (C) 2007, 2008, 2010 Daniel Pittman and Christian Grothoff
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file connection_https.c
* @brief Methods for managing SSL/TLS connections. This file is only
* compiled if ENABLE_HTTPS is set.
* @author Sagie Amir
* @author Christian Grothoff
*/
#include "internal.h"
#include "connection.h"
#include "connection_https.h"
#include "memorypool.h"
#include "response.h"
#include "mhd_mono_clock.h"
#include <gnutls/gnutls.h>
/**
* Callback for receiving data from the socket.
*
* @param connection the MHD_Connection structure
* @param other where to write received data to
* @param i maximum size of other (in bytes)
* @return number of bytes actually received
*/
static ssize_t
recv_tls_adapter (struct MHD_Connection *connection,
void *other,
size_t i)
{
ssize_t res;
if (i > SSIZE_MAX)
i = SSIZE_MAX;
res = gnutls_record_recv (connection->tls_session,
other,
i);
if ( (GNUTLS_E_AGAIN == res) ||
(GNUTLS_E_INTERRUPTED == res) )
{
MHD_socket_set_error_ (MHD_SCKT_EINTR_);
#ifdef EPOLL_SUPPORT
if (GNUTLS_E_AGAIN == res)
connection->epoll_state &= ~MHD_EPOLL_STATE_READ_READY;
#endif
return -1;
}
if (res < 0)
{
/* Likely 'GNUTLS_E_INVALID_SESSION' (client communication
disrupted); set errno to something caller will interpret
correctly as a hard error */
MHD_socket_set_error_ (MHD_SCKT_ECONNRESET_);
connection->tls_read_ready = false;
return res;
}
#ifdef EPOLL_SUPPORT
/* If data not available to fill whole buffer - socket is not read ready anymore. */
if (i > (size_t)res)
connection->epoll_state &= ~MHD_EPOLL_STATE_READ_READY;
#endif /* EPOLL_SUPPORT */
/* Check whether TLS buffers still have some unread data. */
connection->tls_read_ready = ( ((size_t)res == i) &&
(0 != gnutls_record_check_pending (connection->tls_session)) );
return res;
}
/**
* Callback for writing data to the socket.
*
* @param connection the MHD connection structure
* @param other data to write
* @param i number of bytes to write
* @return actual number of bytes written
*/
static ssize_t
send_tls_adapter (struct MHD_Connection *connection,
const void *other,
size_t i)
{
ssize_t res;
if (i > SSIZE_MAX)
i = SSIZE_MAX;
res = gnutls_record_send (connection->tls_session,
other,
i);
if ( (GNUTLS_E_AGAIN == res) ||
(GNUTLS_E_INTERRUPTED == res) )
{
MHD_socket_set_error_ (MHD_SCKT_EINTR_);
#ifdef EPOLL_SUPPORT
if (GNUTLS_E_AGAIN == res)
connection->epoll_state &= ~MHD_EPOLL_STATE_WRITE_READY;
#endif
return -1;
}
if (res < 0)
{
/* some other GNUTLS error, should set 'errno'; as we do not
really understand the error (not listed in GnuTLS
documentation explicitly), we set 'errno' to something that
will cause the connection to fail. */
MHD_socket_set_error_ (MHD_SCKT_ECONNRESET_);
return -1;
}
#ifdef EPOLL_SUPPORT
/* If NOT all available data was sent - socket is not write ready anymore. */
if (i > (size_t)res)
connection->epoll_state &= ~MHD_EPOLL_STATE_WRITE_READY;
#endif /* EPOLL_SUPPORT */
return res;
}
/**
* Give gnuTLS chance to work on the TLS handshake.
*
* @param connection connection to handshake on
* @return #MHD_YES on error or if the handshake is progressing
* #MHD_NO if the handshake has completed successfully
* and we should start to read/write data
*/
static int
run_tls_handshake (struct MHD_Connection *connection)
{
int ret;
if (MHD_TLS_CONNECTION_INIT == connection->state)
{
ret = gnutls_handshake (connection->tls_session);
if (ret == GNUTLS_E_SUCCESS)
{
/* set connection state to enable HTTP processing */
connection->state = MHD_CONNECTION_INIT;
MHD_update_last_activity_ (connection);
return MHD_NO;
}
if ( (GNUTLS_E_AGAIN == ret) ||
(GNUTLS_E_INTERRUPTED == ret) )
{
/* handshake not done */
return MHD_YES;
}
/* handshake failed */
#ifdef HAVE_MESSAGES
MHD_DLOG (connection->daemon,
_("Error: received handshake message out of context\n"));
#endif
MHD_connection_close_ (connection,
MHD_REQUEST_TERMINATED_WITH_ERROR);
return MHD_YES;
}
return MHD_NO;
}
/**
* This function handles a particular SSL/TLS connection when
* it has been determined that there is data to be read off a
* socket. Message processing is done by message type which is
* determined by peeking into the first message type byte of the
* stream.
*
* Error message handling: all fatal level messages cause the
* connection to be terminated.
*
* Application data is forwarded to the underlying daemon for
* processing.
*
* @param connection the source connection
* @return always #MHD_YES (we should continue to process the connection)
*/
static int
MHD_tls_connection_handle_read (struct MHD_Connection *connection)
{
if (MHD_YES == run_tls_handshake (connection))
return MHD_YES;
return MHD_connection_handle_read (connection);
}
/**
* This function was created to handle writes to sockets when it has
* been determined that the socket can be written to. This function
* will forward all write requests to the underlying daemon unless
* the connection has been marked for closing.
*
* @return always #MHD_YES (we should continue to process the connection)
*/
static int
MHD_tls_connection_handle_write (struct MHD_Connection *connection)
{
if (MHD_YES == run_tls_handshake (connection))
return MHD_YES;
return MHD_connection_handle_write (connection);
}
/**
* Set connection callback function to be used through out
* the processing of this secure connection.
*
* @param connection which callbacks should be modified
*/
void
MHD_set_https_callbacks (struct MHD_Connection *connection)
{
connection->read_handler = &MHD_tls_connection_handle_read;
connection->write_handler = &MHD_tls_connection_handle_write;
connection->recv_cls = &recv_tls_adapter;
connection->send_cls = &send_tls_adapter;
}
/**
* Initiate shutdown of TLS layer of connection.
*
* @param connection to use
* @return true if succeed, false otherwise.
*/
bool
MHD_tls_connection_shutdown (struct MHD_Connection *connection)
{
if (! connection->tls_closed)
{
connection->tls_closed =
(GNUTLS_E_SUCCESS == gnutls_bye(connection->tls_session, GNUTLS_SHUT_WR));
}
return connection->tls_closed ? MHD_YES : MHD_NO;;
}
/* end of connection_https.c */
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