remmina_ssh.h

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/*
 * Remmina - The GTK+ Remote Desktop Client
 * Copyright (C) 2009-2011 Vic Lee
 * Copyright (C) 2014-2015 Antenore Gatta, Fabio Castelli, Giovanni Panozzo
 * Copyright (C) 2016-2023 Antenore Gatta, Giovanni Panozzo
 *
 * This program 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 program 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 program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA  02110-1301, USA.
 *
 *  In addition, as a special exception, the copyright holders give
 *  permission to link the code of portions of this program with the
 *  OpenSSL library under certain conditions as described in each
 *  individual source file, and distribute linked combinations
 *  including the two.
 *  You must obey the GNU General Public License in all respects
 *  for all of the code used other than OpenSSL. *  If you modify
 *  file(s) with this exception, you may extend this exception to your
 *  version of the file(s), but you are not obligated to do so. *  If you
 *  do not wish to do so, delete this exception statement from your
 *  version. *  If you delete this exception statement from all source
 *  files in the program, then also delete it here.
 *
 */

#pragma once

#include "config.h"

#ifdef HAVE_LIBSSH

#define LIBSSH_STATIC 1
#include <libssh/libssh.h>
#include <libssh/callbacks.h>
#include <libssh/sftp.h>
#include <pthread.h>
#include "remmina_file.h"
#include "rcw.h"

G_BEGIN_DECLS

/*-----------------------------------------------------------------------------*
*                           SSH Base                                          *
*-----------------------------------------------------------------------------*/

#define REMMINA_SSH(a) ((RemminaSSH *)a)

typedef struct _RemminaSSH {
    ssh_session session;
    ssh_callbacks   callback;
    gboolean    authenticated;

    gchar *     server;
    gint        port;
    gchar *     user;
    gint        auth;
    gchar *     password;
    gchar *     privkeyfile;
    gchar *     certfile;

    gchar *     charset;
    const gchar *   kex_algorithms;
    gchar *     ciphers;
    gchar *     hostkeytypes;
    gchar *     proxycommand;
    gint        stricthostkeycheck;
    const gchar *   compression;

    gchar *     error;

    pthread_mutex_t ssh_mutex;

    gchar *     passphrase;

    gboolean    is_tunnel;
    gboolean    is_multiauth;
    gchar *     tunnel_entrance_host;
    gint        tunnel_entrance_port;

} RemminaSSH;

gchar *remmina_ssh_identity_path(const gchar *id);

/* Auto-detect commonly used private key identities */
gchar *remmina_ssh_find_identity(void);

/* Initialize the ssh object */
gboolean remmina_ssh_init_from_file(RemminaSSH *ssh, RemminaFile *remminafile, gboolean is_tunnel);

/* Initialize the SSH session */
gboolean remmina_ssh_init_session(RemminaSSH *ssh);

/* Authenticate SSH session */


enum remmina_ssh_auth_result {
    REMMINA_SSH_AUTH_NULL,
    REMMINA_SSH_AUTH_SUCCESS,
    REMMINA_SSH_AUTH_PARTIAL,
    REMMINA_SSH_AUTH_AGAIN,
    REMMINA_SSH_AUTH_AUTHFAILED_RETRY_AFTER_PROMPT,
    REMMINA_SSH_AUTH_USERCANCEL,
    REMMINA_SSH_AUTH_FATAL_ERROR,
    REMMINA_SSH_AUTH_RECONNECT
};

enum remmina_ssh_auth_result remmina_ssh_auth(RemminaSSH *ssh, const gchar *password, RemminaProtocolWidget *gp, RemminaFile *remminafile);

enum remmina_ssh_auth_result remmina_ssh_auth_gui(RemminaSSH *ssh, RemminaProtocolWidget *gp, RemminaFile *remminafile);

/* Error handling */
#define remmina_ssh_has_error(ssh) (((RemminaSSH *)ssh)->error != NULL)
void remmina_ssh_set_error(RemminaSSH *ssh, const gchar *fmt);
void remmina_ssh_set_application_error(RemminaSSH *ssh, const gchar *fmt, ...);

/* Converts a string to/from UTF-8, or simply duplicate it if no conversion */
gchar *remmina_ssh_convert(RemminaSSH *ssh, const gchar *from);
gchar *remmina_ssh_unconvert(RemminaSSH *ssh, const gchar *from);

void remmina_ssh_free(RemminaSSH *ssh);

/*-----------------------------------------------------------------------------*
*                           SSH Tunnel                                        *
*-----------------------------------------------------------------------------*/
typedef struct _RemminaSSHTunnel RemminaSSHTunnel;
typedef struct _RemminaSSHTunnelBuffer RemminaSSHTunnelBuffer;

typedef gboolean (*RemminaSSHTunnelCallback) (RemminaSSHTunnel *, gpointer);

enum {
    REMMINA_SSH_TUNNEL_OPEN,
    REMMINA_SSH_TUNNEL_XPORT,
    REMMINA_SSH_TUNNEL_REVERSE
};


struct _RemminaSSHTunnel {
    RemminaSSH          ssh;

    gint                tunnel_type;

    ssh_channel *           channels;
    gint *              sockets;
    RemminaSSHTunnelBuffer **   socketbuffers;
    gint                num_channels;
    gint                max_channels;

    pthread_t           thread;
    gboolean            running;

    gchar *             buffer;
    gint                buffer_len;
    ssh_channel *           channels_out;

    gint                server_sock;
    gchar *             dest;
    gint                port;
    gint                localport;

    gint                remotedisplay;
    gboolean            bindlocalhost;
    gchar *             localdisplay;

    RemminaSSHTunnelCallback    init_func;
    RemminaSSHTunnelCallback    connect_func;
    RemminaSSHTunnelCallback    disconnect_func;
    gpointer            callback_data;

    RemminaSSHTunnelCallback    destroy_func;
    gpointer    destroy_func_callback_data;

};

/* Create a new SSH Tunnel session and connects to the SSH server */
RemminaSSHTunnel *remmina_ssh_tunnel_new_from_file(RemminaFile *remminafile);

/* Open the tunnel. A new thread will be started and listen on a local port.
 * dest: The host:port of the remote destination
 * local_port: The listening local port for the tunnel
 */
gboolean remmina_ssh_tunnel_open(RemminaSSHTunnel *tunnel, const gchar *host, gint port, gint local_port);

/* Cancel accepting any incoming tunnel request.
 * Typically called after the connection has already been establish.
 */
void remmina_ssh_tunnel_cancel_accept(RemminaSSHTunnel *tunnel);

/* start X Port Forwarding */
gboolean remmina_ssh_tunnel_xport(RemminaSSHTunnel *tunnel, gboolean bindlocalhost);

/* start reverse tunnel. A new thread will be started and waiting for incoming connection.
 * port: the port listening on the remote server side.
 * local_port: the port listening on the local side. When connection on the server side comes
 *             in, it will connect to the local port and create the tunnel. The caller should
 *             start listening on the local port before calling it or in connect_func callback.
 */
gboolean remmina_ssh_tunnel_reverse(RemminaSSHTunnel *tunnel, gint port, gint local_port);

/* Tells if the tunnel is terminated after start */
gboolean remmina_ssh_tunnel_terminated(RemminaSSHTunnel *tunnel);

/* Free the tunnel */
void remmina_ssh_tunnel_free(RemminaSSHTunnel *tunnel);

/*-----------------------------------------------------------------------------*
*                           SSH sFTP                                          *
*-----------------------------------------------------------------------------*/

typedef struct _RemminaSFTP {
    RemminaSSH  ssh;

    sftp_session    sftp_sess;
} RemminaSFTP;

/* Create a new SFTP session object from RemminaFile */
RemminaSFTP *remmina_sftp_new_from_file(RemminaFile *remminafile);

/* Create a new SFTP session object from existing SSH session */
RemminaSFTP *remmina_sftp_new_from_ssh(RemminaSSH *ssh);

/* open the SFTP session, assuming the session already authenticated */
gboolean remmina_sftp_open(RemminaSFTP *sftp);

/* Free the SFTP session */
void remmina_sftp_free(RemminaSFTP *sftp);

/*-----------------------------------------------------------------------------*
*                           SSH Shell                                         *
*-----------------------------------------------------------------------------*/
typedef void (*RemminaSSHExitFunc) (gpointer data);

typedef struct _RemminaSSHShell {
    RemminaSSH      ssh;

    gint            master;
    gint            slave;
    gchar *         exec;
    gchar *         run_line;
    pthread_t       thread;
    ssh_channel     channel;
    gboolean        closed;
    RemminaSSHExitFunc  exit_callback;
    gpointer        user_data;
    ssh_event       event;
} RemminaSSHShell;

/* Create a new SSH Shell session object from RemminaFile */
RemminaSSHShell *remmina_ssh_shell_new_from_file(RemminaFile *remminafile);

/* Create a new SSH Shell session object from existing SSH session */
RemminaSSHShell *remmina_ssh_shell_new_from_ssh(RemminaSSH *ssh);

/* open the SSH Shell, assuming the session already authenticated */
gboolean remmina_ssh_shell_open(RemminaSSHShell *shell, RemminaSSHExitFunc exit_callback, gpointer data);

/* Change the SSH Shell terminal size */
void remmina_ssh_shell_set_size(RemminaSSHShell *shell, gint columns, gint rows);

/* Free the SFTP session */
void remmina_ssh_shell_free(RemminaSSHShell *shell);

G_END_DECLS

#else

#define RemminaSSH void
#define RemminaSSHTunnel void
#define RemminaSFTP void
#define RemminaSSHShell void
typedef void (*RemminaSSHTunnelCallback)(void);

#endif /* HAVE_LIBSSH */