e0fbb1d2de
"non-echoed" characters are still echoed back in a null packet, as well as pad passwords sent to not give hints to the length otherwise. Obtained from: OpenBSD
296 lines
11 KiB
C
296 lines
11 KiB
C
/*
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* Author: Tatu Ylonen <ylo@cs.hut.fi>
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* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
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* All rights reserved
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*
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* As far as I am concerned, the code I have written for this software
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* can be used freely for any purpose. Any derived versions of this
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* software must be clearly marked as such, and if the derived work is
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* incompatible with the protocol description in the RFC file, it must be
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* called by a name other than "ssh" or "Secure Shell".
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*/
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/*
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* Copyright (c) 2000 Markus Friedl. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/* RCSID("$FreeBSD$"); */
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/* RCSID("$OpenBSD: channels.h,v 1.22 2000/10/27 07:48:22 markus Exp $"); */
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#ifndef CHANNELS_H
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#define CHANNELS_H
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/* Definitions for channel types. */
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#define SSH_CHANNEL_FREE 0 /* This channel is free (unused). */
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#define SSH_CHANNEL_X11_LISTENER 1 /* Listening for inet X11 conn. */
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#define SSH_CHANNEL_PORT_LISTENER 2 /* Listening on a port. */
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#define SSH_CHANNEL_OPENING 3 /* waiting for confirmation */
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#define SSH_CHANNEL_OPEN 4 /* normal open two-way channel */
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#define SSH_CHANNEL_CLOSED 5 /* waiting for close confirmation */
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#define SSH_CHANNEL_AUTH_SOCKET 6 /* authentication socket */
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#define SSH_CHANNEL_X11_OPEN 7 /* reading first X11 packet */
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#define SSH_CHANNEL_INPUT_DRAINING 8 /* sending remaining data to conn */
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#define SSH_CHANNEL_OUTPUT_DRAINING 9 /* sending remaining data to app */
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#define SSH_CHANNEL_LARVAL 10 /* larval session */
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#define SSH_CHANNEL_MAX_TYPE 11
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/*
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* Data structure for channel data. This is iniailized in channel_allocate
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* and cleared in channel_free.
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*/
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struct Channel;
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typedef struct Channel Channel;
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typedef void channel_callback_fn(int id, void *arg);
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typedef int channel_filter_fn(struct Channel *c, char *buf, int len);
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struct Channel {
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int type; /* channel type/state */
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int self; /* my own channel identifier */
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int remote_id; /* channel identifier for remote peer */
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/* peer can be reached over encrypted connection, via packet-sent */
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int istate; /* input from channel (state of receive half) */
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int ostate; /* output to channel (state of transmit half) */
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int flags; /* close sent/rcvd */
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int rfd; /* read fd */
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int wfd; /* write fd */
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int efd; /* extended fd */
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int sock; /* sock fd */
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int isatty; /* rfd is a tty */
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Buffer input; /* data read from socket, to be sent over
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* encrypted connection */
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Buffer output; /* data received over encrypted connection for
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* send on socket */
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Buffer extended;
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char path[200]; /* path for unix domain sockets, or host name
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* for forwards */
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int listening_port; /* port being listened for forwards */
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int host_port; /* remote port to connect for forwards */
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char *remote_name; /* remote hostname */
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int remote_window;
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int remote_maxpacket;
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int local_window;
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int local_window_max;
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int local_consumed;
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int local_maxpacket;
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int extended_usage;
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char *ctype; /* type */
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/* callback */
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channel_callback_fn *cb_fn;
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void *cb_arg;
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int cb_event;
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channel_callback_fn *dettach_user;
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/* filter */
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channel_filter_fn *input_filter;
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};
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#define CHAN_EXTENDED_IGNORE 0
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#define CHAN_EXTENDED_READ 1
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#define CHAN_EXTENDED_WRITE 2
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/* default window/packet sizes for tcp/x11-fwd-channel */
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#define CHAN_SES_WINDOW_DEFAULT (32*1024)
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#define CHAN_SES_PACKET_DEFAULT (CHAN_SES_WINDOW_DEFAULT/2)
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#define CHAN_TCP_WINDOW_DEFAULT (32*1024)
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#define CHAN_TCP_PACKET_DEFAULT (CHAN_TCP_WINDOW_DEFAULT/2)
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#define CHAN_X11_WINDOW_DEFAULT (4*1024)
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#define CHAN_X11_PACKET_DEFAULT (CHAN_X11_WINDOW_DEFAULT/2)
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void channel_open(int id);
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void channel_request(int id, char *service, int wantconfirm);
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void channel_request_start(int id, char *service, int wantconfirm);
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void channel_register_callback(int id, int mtype, channel_callback_fn *fn, void *arg);
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void channel_register_cleanup(int id, channel_callback_fn *fn);
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void channel_register_filter(int id, channel_filter_fn *fn);
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void channel_cancel_cleanup(int id);
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Channel *channel_lookup(int id);
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int
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channel_new(char *ctype, int type, int rfd, int wfd, int efd,
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int window, int maxpack, int extended_usage, char *remote_name,
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int nonblock);
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void
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channel_set_fds(int id, int rfd, int wfd, int efd,
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int extusage, int nonblock);
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void deny_input_open(int type, int plen, void *ctxt);
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void channel_input_channel_request(int type, int plen, void *ctxt);
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void channel_input_close(int type, int plen, void *ctxt);
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void channel_input_close_confirmation(int type, int plen, void *ctxt);
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void channel_input_data(int type, int plen, void *ctxt);
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void channel_input_extended_data(int type, int plen, void *ctxt);
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void channel_input_ieof(int type, int plen, void *ctxt);
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void channel_input_oclose(int type, int plen, void *ctxt);
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void channel_input_open_confirmation(int type, int plen, void *ctxt);
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void channel_input_open_failure(int type, int plen, void *ctxt);
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void channel_input_port_open(int type, int plen, void *ctxt);
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void channel_input_window_adjust(int type, int plen, void *ctxt);
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void channel_input_open(int type, int plen, void *ctxt);
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/* Sets specific protocol options. */
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void channel_set_options(int hostname_in_open);
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/*
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* Allocate a new channel object and set its type and socket. Remote_name
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* must have been allocated with xmalloc; this will free it when the channel
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* is freed.
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*/
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int channel_allocate(int type, int sock, char *remote_name);
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/* Free the channel and close its socket. */
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void channel_free(int channel);
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/* Add any bits relevant to channels in select bitmasks. */
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void channel_prepare_select(fd_set * readset, fd_set * writeset);
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/*
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* After select, perform any appropriate operations for channels which have
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* events pending.
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*/
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void channel_after_select(fd_set * readset, fd_set * writeset);
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/* If there is data to send to the connection, send some of it now. */
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void channel_output_poll(void);
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/* Returns true if no channel has too much buffered data. */
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int channel_not_very_much_buffered_data(void);
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/* This closes any sockets that are listening for connections; this removes
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any unix domain sockets. */
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void channel_stop_listening(void);
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/*
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* Closes the sockets of all channels. This is used to close extra file
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* descriptors after a fork.
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*/
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void channel_close_all(void);
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/* Returns the maximum file descriptor number used by the channels. */
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int channel_max_fd(void);
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/* Returns true if there is still an open channel over the connection. */
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int channel_still_open(void);
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/*
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* Returns a string containing a list of all open channels. The list is
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* suitable for displaying to the user. It uses crlf instead of newlines.
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* The caller should free the string with xfree.
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*/
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char *channel_open_message(void);
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/*
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* Initiate forwarding of connections to local port "port" through the secure
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* channel to host:port from remote side. This never returns if there was an
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* error.
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*/
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void
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channel_request_local_forwarding(u_short port, const char *host,
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u_short remote_port, int gateway_ports);
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/*
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* Initiate forwarding of connections to port "port" on remote host through
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* the secure channel to host:port from local side. This never returns if
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* there was an error. This registers that open requests for that port are
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* permitted.
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*/
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void
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channel_request_remote_forwarding(u_short port, const char *host,
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u_short remote_port);
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/*
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* Permits opening to any host/port in SSH_MSG_PORT_OPEN. This is usually
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* called by the server, because the user could connect to any port anyway,
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* and the server has no way to know but to trust the client anyway.
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*/
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void channel_permit_all_opens(void);
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/*
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* This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
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* listening for the port, and sends back a success reply (or disconnect
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* message if there was an error). This never returns if there was an error.
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*/
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void channel_input_port_forward_request(int is_root, int gateway_ports);
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/*
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* Creates a port for X11 connections, and starts listening for it. Returns
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* the display name, or NULL if an error was encountered.
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*/
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char *x11_create_display(int screen);
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/*
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* Creates an internet domain socket for listening for X11 connections.
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* Returns a suitable value for the DISPLAY variable, or NULL if an error
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* occurs.
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*/
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char *x11_create_display_inet(int screen, int x11_display_offset);
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/*
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* This is called when SSH_SMSG_X11_OPEN is received. The packet contains
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* the remote channel number. We should do whatever we want, and respond
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* with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
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*/
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void x11_input_open(int type, int plen, void *ctxt);
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/*
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* Requests forwarding of X11 connections. This should be called on the
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* client only.
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*/
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void x11_request_forwarding(void);
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/*
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* Requests forwarding for X11 connections, with authentication spoofing.
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* This should be called in the client only.
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*/
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void
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x11_request_forwarding_with_spoofing(int client_session_id,
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const char *proto, const char *data);
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/* Sends a message to the server to request authentication fd forwarding. */
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void auth_request_forwarding(void);
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/*
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* Returns the name of the forwarded authentication socket. Returns NULL if
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* there is no forwarded authentication socket. The returned value points to
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* a static buffer.
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*/
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char *auth_get_socket_name(void);
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/*
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* This is called to process SSH_CMSG_AGENT_REQUEST_FORWARDING on the server.
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* This starts forwarding authentication requests.
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*/
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int auth_input_request_forwarding(struct passwd * pw);
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/* This is called to process an SSH_SMSG_AGENT_OPEN message. */
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void auth_input_open_request(int type, int plen, void *ctxt);
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/* XXX */
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int channel_connect_to(const char *host, u_short host_port);
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int x11_connect_display(void);
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#endif
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