1/* $OpenBSD: channels.c,v 1.319 2012/12/02 20:46:11 djm Exp $ */
2/*
3 * Author: Tatu Ylonen <ylo@cs.hut.fi>
4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5 *                    All rights reserved
6 * This file contains functions for generic socket connection forwarding.
7 * There is also code for initiating connection forwarding for X11 connections,
8 * arbitrary tcp/ip connections, and the authentication agent connection.
9 *
10 * As far as I am concerned, the code I have written for this software
11 * can be used freely for any purpose.  Any derived versions of this
12 * software must be clearly marked as such, and if the derived work is
13 * incompatible with the protocol description in the RFC file, it must be
14 * called by a name other than "ssh" or "Secure Shell".
15 *
16 * SSH2 support added by Markus Friedl.
17 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl.  All rights reserved.
18 * Copyright (c) 1999 Dug Song.  All rights reserved.
19 * Copyright (c) 1999 Theo de Raadt.  All rights reserved.
20 *
21 * Redistribution and use in source and binary forms, with or without
22 * modification, are permitted provided that the following conditions
23 * are met:
24 * 1. Redistributions of source code must retain the above copyright
25 *    notice, this list of conditions and the following disclaimer.
26 * 2. Redistributions in binary form must reproduce the above copyright
27 *    notice, this list of conditions and the following disclaimer in the
28 *    documentation and/or other materials provided with the distribution.
29 *
30 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
31 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
32 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
33 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
34 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
35 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
36 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
37 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
38 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
39 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
40 */
41
42#include "includes.h"
43
44#include <sys/types.h>
45#include <sys/ioctl.h>
46#include <sys/un.h>
47#include <sys/socket.h>
48#ifdef HAVE_SYS_TIME_H
49# include <sys/time.h>
50#endif
51
52#include <netinet/in.h>
53#include <arpa/inet.h>
54
55#include <errno.h>
56#include <fcntl.h>
57#include <netdb.h>
58#include <stdio.h>
59#include <stdlib.h>
60#include <string.h>
61#include <termios.h>
62#include <unistd.h>
63#include <stdarg.h>
64
65#include "openbsd-compat/sys-queue.h"
66#include "xmalloc.h"
67#include "ssh.h"
68#include "ssh1.h"
69#include "ssh2.h"
70#include "packet.h"
71#include "log.h"
72#include "misc.h"
73#include "buffer.h"
74#include "channels.h"
75#include "compat.h"
76#include "canohost.h"
77#include "key.h"
78#include "authfd.h"
79#include "pathnames.h"
80
81/* -- channel core */
82
83/*
84 * Pointer to an array containing all allocated channels.  The array is
85 * dynamically extended as needed.
86 */
87static Channel **channels = NULL;
88
89/*
90 * Size of the channel array.  All slots of the array must always be
91 * initialized (at least the type field); unused slots set to NULL
92 */
93static u_int channels_alloc = 0;
94
95/*
96 * Maximum file descriptor value used in any of the channels.  This is
97 * updated in channel_new.
98 */
99static int channel_max_fd = 0;
100
101
102/* -- tcp forwarding */
103
104/*
105 * Data structure for storing which hosts are permitted for forward requests.
106 * The local sides of any remote forwards are stored in this array to prevent
107 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local
108 * network (which might be behind a firewall).
109 */
110typedef struct {
111	char *host_to_connect;		/* Connect to 'host'. */
112	u_short port_to_connect;	/* Connect to 'port'. */
113	u_short listen_port;		/* Remote side should listen port number. */
114} ForwardPermission;
115
116/* List of all permitted host/port pairs to connect by the user. */
117static ForwardPermission *permitted_opens = NULL;
118
119/* List of all permitted host/port pairs to connect by the admin. */
120static ForwardPermission *permitted_adm_opens = NULL;
121
122/* Number of permitted host/port pairs in the array permitted by the user. */
123static int num_permitted_opens = 0;
124
125/* Number of permitted host/port pair in the array permitted by the admin. */
126static int num_adm_permitted_opens = 0;
127
128/* special-case port number meaning allow any port */
129#define FWD_PERMIT_ANY_PORT	0
130
131/*
132 * If this is true, all opens are permitted.  This is the case on the server
133 * on which we have to trust the client anyway, and the user could do
134 * anything after logging in anyway.
135 */
136static int all_opens_permitted = 0;
137
138
139/* -- X11 forwarding */
140
141/* Maximum number of fake X11 displays to try. */
142#define MAX_DISPLAYS  1000
143
144/* Saved X11 local (client) display. */
145static char *x11_saved_display = NULL;
146
147/* Saved X11 authentication protocol name. */
148static char *x11_saved_proto = NULL;
149
150/* Saved X11 authentication data.  This is the real data. */
151static char *x11_saved_data = NULL;
152static u_int x11_saved_data_len = 0;
153
154/*
155 * Fake X11 authentication data.  This is what the server will be sending us;
156 * we should replace any occurrences of this by the real data.
157 */
158static u_char *x11_fake_data = NULL;
159static u_int x11_fake_data_len;
160
161
162/* -- agent forwarding */
163
164#define	NUM_SOCKS	10
165
166/* AF_UNSPEC or AF_INET or AF_INET6 */
167static int IPv4or6 = AF_UNSPEC;
168
169/* helper */
170static void port_open_helper(Channel *c, char *rtype);
171
172/* non-blocking connect helpers */
173static int connect_next(struct channel_connect *);
174static void channel_connect_ctx_free(struct channel_connect *);
175
176/* -- channel core */
177
178Channel *
179channel_by_id(int id)
180{
181	Channel *c;
182
183	if (id < 0 || (u_int)id >= channels_alloc) {
184		logit("channel_by_id: %d: bad id", id);
185		return NULL;
186	}
187	c = channels[id];
188	if (c == NULL) {
189		logit("channel_by_id: %d: bad id: channel free", id);
190		return NULL;
191	}
192	return c;
193}
194
195/*
196 * Returns the channel if it is allowed to receive protocol messages.
197 * Private channels, like listening sockets, may not receive messages.
198 */
199Channel *
200channel_lookup(int id)
201{
202	Channel *c;
203
204	if ((c = channel_by_id(id)) == NULL)
205		return (NULL);
206
207	switch (c->type) {
208	case SSH_CHANNEL_X11_OPEN:
209	case SSH_CHANNEL_LARVAL:
210	case SSH_CHANNEL_CONNECTING:
211	case SSH_CHANNEL_DYNAMIC:
212	case SSH_CHANNEL_OPENING:
213	case SSH_CHANNEL_OPEN:
214	case SSH_CHANNEL_INPUT_DRAINING:
215	case SSH_CHANNEL_OUTPUT_DRAINING:
216		return (c);
217	}
218	logit("Non-public channel %d, type %d.", id, c->type);
219	return (NULL);
220}
221
222/*
223 * Register filedescriptors for a channel, used when allocating a channel or
224 * when the channel consumer/producer is ready, e.g. shell exec'd
225 */
226static void
227channel_register_fds(Channel *c, int rfd, int wfd, int efd,
228    int extusage, int nonblock, int is_tty)
229{
230	/* Update the maximum file descriptor value. */
231	channel_max_fd = MAX(channel_max_fd, rfd);
232	channel_max_fd = MAX(channel_max_fd, wfd);
233	channel_max_fd = MAX(channel_max_fd, efd);
234
235	if (rfd != -1)
236		fcntl(rfd, F_SETFD, FD_CLOEXEC);
237	if (wfd != -1 && wfd != rfd)
238		fcntl(wfd, F_SETFD, FD_CLOEXEC);
239	if (efd != -1 && efd != rfd && efd != wfd)
240		fcntl(efd, F_SETFD, FD_CLOEXEC);
241
242	c->rfd = rfd;
243	c->wfd = wfd;
244	c->sock = (rfd == wfd) ? rfd : -1;
245	c->efd = efd;
246	c->extended_usage = extusage;
247
248	if ((c->isatty = is_tty) != 0)
249		debug2("channel %d: rfd %d isatty", c->self, c->rfd);
250	c->wfd_isatty = is_tty || isatty(c->wfd);
251
252	/* enable nonblocking mode */
253	if (nonblock) {
254		if (rfd != -1)
255			set_nonblock(rfd);
256		if (wfd != -1)
257			set_nonblock(wfd);
258		if (efd != -1)
259			set_nonblock(efd);
260	}
261}
262
263/*
264 * Allocate a new channel object and set its type and socket. This will cause
265 * remote_name to be freed.
266 */
267Channel *
268channel_new(char *ctype, int type, int rfd, int wfd, int efd,
269    u_int window, u_int maxpack, int extusage, char *remote_name, int nonblock)
270{
271	int found;
272	u_int i;
273	Channel *c;
274
275	/* Do initial allocation if this is the first call. */
276	if (channels_alloc == 0) {
277		channels_alloc = 10;
278		channels = xcalloc(channels_alloc, sizeof(Channel *));
279		for (i = 0; i < channels_alloc; i++)
280			channels[i] = NULL;
281	}
282	/* Try to find a free slot where to put the new channel. */
283	for (found = -1, i = 0; i < channels_alloc; i++)
284		if (channels[i] == NULL) {
285			/* Found a free slot. */
286			found = (int)i;
287			break;
288		}
289	if (found < 0) {
290		/* There are no free slots.  Take last+1 slot and expand the array.  */
291		found = channels_alloc;
292		if (channels_alloc > 10000)
293			fatal("channel_new: internal error: channels_alloc %d "
294			    "too big.", channels_alloc);
295		channels = xrealloc(channels, channels_alloc + 10,
296		    sizeof(Channel *));
297		channels_alloc += 10;
298		debug2("channel: expanding %d", channels_alloc);
299		for (i = found; i < channels_alloc; i++)
300			channels[i] = NULL;
301	}
302	/* Initialize and return new channel. */
303	c = channels[found] = xcalloc(1, sizeof(Channel));
304	buffer_init(&c->input);
305	buffer_init(&c->output);
306	buffer_init(&c->extended);
307	c->path = NULL;
308	c->listening_addr = NULL;
309	c->listening_port = 0;
310	c->ostate = CHAN_OUTPUT_OPEN;
311	c->istate = CHAN_INPUT_OPEN;
312	c->flags = 0;
313	channel_register_fds(c, rfd, wfd, efd, extusage, nonblock, 0);
314	c->notbefore = 0;
315	c->self = found;
316	c->type = type;
317	c->ctype = ctype;
318	c->local_window = window;
319	c->local_window_max = window;
320	c->local_consumed = 0;
321	c->local_maxpacket = maxpack;
322	c->remote_id = -1;
323	c->remote_name = xstrdup(remote_name);
324	c->remote_window = 0;
325	c->remote_maxpacket = 0;
326	c->force_drain = 0;
327	c->single_connection = 0;
328	c->detach_user = NULL;
329	c->detach_close = 0;
330	c->open_confirm = NULL;
331	c->open_confirm_ctx = NULL;
332	c->input_filter = NULL;
333	c->output_filter = NULL;
334	c->filter_ctx = NULL;
335	c->filter_cleanup = NULL;
336	c->ctl_chan = -1;
337	c->mux_rcb = NULL;
338	c->mux_ctx = NULL;
339	c->mux_pause = 0;
340	c->delayed = 1;		/* prevent call to channel_post handler */
341	TAILQ_INIT(&c->status_confirms);
342	debug("channel %d: new [%s]", found, remote_name);
343	return c;
344}
345
346static int
347channel_find_maxfd(void)
348{
349	u_int i;
350	int max = 0;
351	Channel *c;
352
353	for (i = 0; i < channels_alloc; i++) {
354		c = channels[i];
355		if (c != NULL) {
356			max = MAX(max, c->rfd);
357			max = MAX(max, c->wfd);
358			max = MAX(max, c->efd);
359		}
360	}
361	return max;
362}
363
364int
365channel_close_fd(int *fdp)
366{
367	int ret = 0, fd = *fdp;
368
369	if (fd != -1) {
370		ret = close(fd);
371		*fdp = -1;
372		if (fd == channel_max_fd)
373			channel_max_fd = channel_find_maxfd();
374	}
375	return ret;
376}
377
378/* Close all channel fd/socket. */
379static void
380channel_close_fds(Channel *c)
381{
382	channel_close_fd(&c->sock);
383	channel_close_fd(&c->rfd);
384	channel_close_fd(&c->wfd);
385	channel_close_fd(&c->efd);
386}
387
388/* Free the channel and close its fd/socket. */
389void
390channel_free(Channel *c)
391{
392	char *s;
393	u_int i, n;
394	struct channel_confirm *cc;
395
396	for (n = 0, i = 0; i < channels_alloc; i++)
397		if (channels[i])
398			n++;
399	debug("channel %d: free: %s, nchannels %u", c->self,
400	    c->remote_name ? c->remote_name : "???", n);
401
402	s = channel_open_message();
403	debug3("channel %d: status: %s", c->self, s);
404	xfree(s);
405
406	if (c->sock != -1)
407		shutdown(c->sock, SHUT_RDWR);
408	channel_close_fds(c);
409	buffer_free(&c->input);
410	buffer_free(&c->output);
411	buffer_free(&c->extended);
412	if (c->remote_name) {
413		xfree(c->remote_name);
414		c->remote_name = NULL;
415	}
416	if (c->path) {
417		xfree(c->path);
418		c->path = NULL;
419	}
420	if (c->listening_addr) {
421		xfree(c->listening_addr);
422		c->listening_addr = NULL;
423	}
424	while ((cc = TAILQ_FIRST(&c->status_confirms)) != NULL) {
425		if (cc->abandon_cb != NULL)
426			cc->abandon_cb(c, cc->ctx);
427		TAILQ_REMOVE(&c->status_confirms, cc, entry);
428		bzero(cc, sizeof(*cc));
429		xfree(cc);
430	}
431	if (c->filter_cleanup != NULL && c->filter_ctx != NULL)
432		c->filter_cleanup(c->self, c->filter_ctx);
433	channels[c->self] = NULL;
434	xfree(c);
435}
436
437void
438channel_free_all(void)
439{
440	u_int i;
441
442	for (i = 0; i < channels_alloc; i++)
443		if (channels[i] != NULL)
444			channel_free(channels[i]);
445}
446
447/*
448 * Closes the sockets/fds of all channels.  This is used to close extra file
449 * descriptors after a fork.
450 */
451void
452channel_close_all(void)
453{
454	u_int i;
455
456	for (i = 0; i < channels_alloc; i++)
457		if (channels[i] != NULL)
458			channel_close_fds(channels[i]);
459}
460
461/*
462 * Stop listening to channels.
463 */
464void
465channel_stop_listening(void)
466{
467	u_int i;
468	Channel *c;
469
470	for (i = 0; i < channels_alloc; i++) {
471		c = channels[i];
472		if (c != NULL) {
473			switch (c->type) {
474			case SSH_CHANNEL_AUTH_SOCKET:
475			case SSH_CHANNEL_PORT_LISTENER:
476			case SSH_CHANNEL_RPORT_LISTENER:
477			case SSH_CHANNEL_X11_LISTENER:
478				channel_close_fd(&c->sock);
479				channel_free(c);
480				break;
481			}
482		}
483	}
484}
485
486/*
487 * Returns true if no channel has too much buffered data, and false if one or
488 * more channel is overfull.
489 */
490int
491channel_not_very_much_buffered_data(void)
492{
493	u_int i;
494	Channel *c;
495
496	for (i = 0; i < channels_alloc; i++) {
497		c = channels[i];
498		if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
499#if 0
500			if (!compat20 &&
501			    buffer_len(&c->input) > packet_get_maxsize()) {
502				debug2("channel %d: big input buffer %d",
503				    c->self, buffer_len(&c->input));
504				return 0;
505			}
506#endif
507			if (buffer_len(&c->output) > packet_get_maxsize()) {
508				debug2("channel %d: big output buffer %u > %u",
509				    c->self, buffer_len(&c->output),
510				    packet_get_maxsize());
511				return 0;
512			}
513		}
514	}
515	return 1;
516}
517
518/* Returns true if any channel is still open. */
519int
520channel_still_open(void)
521{
522	u_int i;
523	Channel *c;
524
525	for (i = 0; i < channels_alloc; i++) {
526		c = channels[i];
527		if (c == NULL)
528			continue;
529		switch (c->type) {
530		case SSH_CHANNEL_X11_LISTENER:
531		case SSH_CHANNEL_PORT_LISTENER:
532		case SSH_CHANNEL_RPORT_LISTENER:
533		case SSH_CHANNEL_MUX_LISTENER:
534		case SSH_CHANNEL_CLOSED:
535		case SSH_CHANNEL_AUTH_SOCKET:
536		case SSH_CHANNEL_DYNAMIC:
537		case SSH_CHANNEL_CONNECTING:
538		case SSH_CHANNEL_ZOMBIE:
539			continue;
540		case SSH_CHANNEL_LARVAL:
541			if (!compat20)
542				fatal("cannot happen: SSH_CHANNEL_LARVAL");
543			continue;
544		case SSH_CHANNEL_OPENING:
545		case SSH_CHANNEL_OPEN:
546		case SSH_CHANNEL_X11_OPEN:
547		case SSH_CHANNEL_MUX_CLIENT:
548			return 1;
549		case SSH_CHANNEL_INPUT_DRAINING:
550		case SSH_CHANNEL_OUTPUT_DRAINING:
551			if (!compat13)
552				fatal("cannot happen: OUT_DRAIN");
553			return 1;
554		default:
555			fatal("channel_still_open: bad channel type %d", c->type);
556			/* NOTREACHED */
557		}
558	}
559	return 0;
560}
561
562/* Returns the id of an open channel suitable for keepaliving */
563int
564channel_find_open(void)
565{
566	u_int i;
567	Channel *c;
568
569	for (i = 0; i < channels_alloc; i++) {
570		c = channels[i];
571		if (c == NULL || c->remote_id < 0)
572			continue;
573		switch (c->type) {
574		case SSH_CHANNEL_CLOSED:
575		case SSH_CHANNEL_DYNAMIC:
576		case SSH_CHANNEL_X11_LISTENER:
577		case SSH_CHANNEL_PORT_LISTENER:
578		case SSH_CHANNEL_RPORT_LISTENER:
579		case SSH_CHANNEL_MUX_LISTENER:
580		case SSH_CHANNEL_MUX_CLIENT:
581		case SSH_CHANNEL_OPENING:
582		case SSH_CHANNEL_CONNECTING:
583		case SSH_CHANNEL_ZOMBIE:
584			continue;
585		case SSH_CHANNEL_LARVAL:
586		case SSH_CHANNEL_AUTH_SOCKET:
587		case SSH_CHANNEL_OPEN:
588		case SSH_CHANNEL_X11_OPEN:
589			return i;
590		case SSH_CHANNEL_INPUT_DRAINING:
591		case SSH_CHANNEL_OUTPUT_DRAINING:
592			if (!compat13)
593				fatal("cannot happen: OUT_DRAIN");
594			return i;
595		default:
596			fatal("channel_find_open: bad channel type %d", c->type);
597			/* NOTREACHED */
598		}
599	}
600	return -1;
601}
602
603
604/*
605 * Returns a message describing the currently open forwarded connections,
606 * suitable for sending to the client.  The message contains crlf pairs for
607 * newlines.
608 */
609char *
610channel_open_message(void)
611{
612	Buffer buffer;
613	Channel *c;
614	char buf[1024], *cp;
615	u_int i;
616
617	buffer_init(&buffer);
618	snprintf(buf, sizeof buf, "The following connections are open:\r\n");
619	buffer_append(&buffer, buf, strlen(buf));
620	for (i = 0; i < channels_alloc; i++) {
621		c = channels[i];
622		if (c == NULL)
623			continue;
624		switch (c->type) {
625		case SSH_CHANNEL_X11_LISTENER:
626		case SSH_CHANNEL_PORT_LISTENER:
627		case SSH_CHANNEL_RPORT_LISTENER:
628		case SSH_CHANNEL_CLOSED:
629		case SSH_CHANNEL_AUTH_SOCKET:
630		case SSH_CHANNEL_ZOMBIE:
631		case SSH_CHANNEL_MUX_CLIENT:
632		case SSH_CHANNEL_MUX_LISTENER:
633			continue;
634		case SSH_CHANNEL_LARVAL:
635		case SSH_CHANNEL_OPENING:
636		case SSH_CHANNEL_CONNECTING:
637		case SSH_CHANNEL_DYNAMIC:
638		case SSH_CHANNEL_OPEN:
639		case SSH_CHANNEL_X11_OPEN:
640		case SSH_CHANNEL_INPUT_DRAINING:
641		case SSH_CHANNEL_OUTPUT_DRAINING:
642			snprintf(buf, sizeof buf,
643			    "  #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d cc %d)\r\n",
644			    c->self, c->remote_name,
645			    c->type, c->remote_id,
646			    c->istate, buffer_len(&c->input),
647			    c->ostate, buffer_len(&c->output),
648			    c->rfd, c->wfd, c->ctl_chan);
649			buffer_append(&buffer, buf, strlen(buf));
650			continue;
651		default:
652			fatal("channel_open_message: bad channel type %d", c->type);
653			/* NOTREACHED */
654		}
655	}
656	buffer_append(&buffer, "\0", 1);
657	cp = xstrdup(buffer_ptr(&buffer));
658	buffer_free(&buffer);
659	return cp;
660}
661
662void
663channel_send_open(int id)
664{
665	Channel *c = channel_lookup(id);
666
667	if (c == NULL) {
668		logit("channel_send_open: %d: bad id", id);
669		return;
670	}
671	debug2("channel %d: send open", id);
672	packet_start(SSH2_MSG_CHANNEL_OPEN);
673	packet_put_cstring(c->ctype);
674	packet_put_int(c->self);
675	packet_put_int(c->local_window);
676	packet_put_int(c->local_maxpacket);
677	packet_send();
678}
679
680void
681channel_request_start(int id, char *service, int wantconfirm)
682{
683	Channel *c = channel_lookup(id);
684
685	if (c == NULL) {
686		logit("channel_request_start: %d: unknown channel id", id);
687		return;
688	}
689	debug2("channel %d: request %s confirm %d", id, service, wantconfirm);
690	packet_start(SSH2_MSG_CHANNEL_REQUEST);
691	packet_put_int(c->remote_id);
692	packet_put_cstring(service);
693	packet_put_char(wantconfirm);
694}
695
696void
697channel_register_status_confirm(int id, channel_confirm_cb *cb,
698    channel_confirm_abandon_cb *abandon_cb, void *ctx)
699{
700	struct channel_confirm *cc;
701	Channel *c;
702
703	if ((c = channel_lookup(id)) == NULL)
704		fatal("channel_register_expect: %d: bad id", id);
705
706	cc = xmalloc(sizeof(*cc));
707	cc->cb = cb;
708	cc->abandon_cb = abandon_cb;
709	cc->ctx = ctx;
710	TAILQ_INSERT_TAIL(&c->status_confirms, cc, entry);
711}
712
713void
714channel_register_open_confirm(int id, channel_open_fn *fn, void *ctx)
715{
716	Channel *c = channel_lookup(id);
717
718	if (c == NULL) {
719		logit("channel_register_open_confirm: %d: bad id", id);
720		return;
721	}
722	c->open_confirm = fn;
723	c->open_confirm_ctx = ctx;
724}
725
726void
727channel_register_cleanup(int id, channel_callback_fn *fn, int do_close)
728{
729	Channel *c = channel_by_id(id);
730
731	if (c == NULL) {
732		logit("channel_register_cleanup: %d: bad id", id);
733		return;
734	}
735	c->detach_user = fn;
736	c->detach_close = do_close;
737}
738
739void
740channel_cancel_cleanup(int id)
741{
742	Channel *c = channel_by_id(id);
743
744	if (c == NULL) {
745		logit("channel_cancel_cleanup: %d: bad id", id);
746		return;
747	}
748	c->detach_user = NULL;
749	c->detach_close = 0;
750}
751
752void
753channel_register_filter(int id, channel_infilter_fn *ifn,
754    channel_outfilter_fn *ofn, channel_filter_cleanup_fn *cfn, void *ctx)
755{
756	Channel *c = channel_lookup(id);
757
758	if (c == NULL) {
759		logit("channel_register_filter: %d: bad id", id);
760		return;
761	}
762	c->input_filter = ifn;
763	c->output_filter = ofn;
764	c->filter_ctx = ctx;
765	c->filter_cleanup = cfn;
766}
767
768void
769channel_set_fds(int id, int rfd, int wfd, int efd,
770    int extusage, int nonblock, int is_tty, u_int window_max)
771{
772	Channel *c = channel_lookup(id);
773
774	if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
775		fatal("channel_activate for non-larval channel %d.", id);
776	channel_register_fds(c, rfd, wfd, efd, extusage, nonblock, is_tty);
777	c->type = SSH_CHANNEL_OPEN;
778	c->local_window = c->local_window_max = window_max;
779	packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
780	packet_put_int(c->remote_id);
781	packet_put_int(c->local_window);
782	packet_send();
783}
784
785/*
786 * 'channel_pre*' are called just before select() to add any bits relevant to
787 * channels in the select bitmasks.
788 */
789/*
790 * 'channel_post*': perform any appropriate operations for channels which
791 * have events pending.
792 */
793typedef void chan_fn(Channel *c, fd_set *readset, fd_set *writeset);
794chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
795chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
796
797/* ARGSUSED */
798static void
799channel_pre_listener(Channel *c, fd_set *readset, fd_set *writeset)
800{
801	FD_SET(c->sock, readset);
802}
803
804/* ARGSUSED */
805static void
806channel_pre_connecting(Channel *c, fd_set *readset, fd_set *writeset)
807{
808	debug3("channel %d: waiting for connection", c->self);
809	FD_SET(c->sock, writeset);
810}
811
812static void
813channel_pre_open_13(Channel *c, fd_set *readset, fd_set *writeset)
814{
815	if (buffer_len(&c->input) < packet_get_maxsize())
816		FD_SET(c->sock, readset);
817	if (buffer_len(&c->output) > 0)
818		FD_SET(c->sock, writeset);
819}
820
821static void
822channel_pre_open(Channel *c, fd_set *readset, fd_set *writeset)
823{
824	u_int limit = compat20 ? c->remote_window : packet_get_maxsize();
825
826	if (c->istate == CHAN_INPUT_OPEN &&
827	    limit > 0 &&
828	    buffer_len(&c->input) < limit &&
829	    buffer_check_alloc(&c->input, CHAN_RBUF))
830		FD_SET(c->rfd, readset);
831	if (c->ostate == CHAN_OUTPUT_OPEN ||
832	    c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
833		if (buffer_len(&c->output) > 0) {
834			FD_SET(c->wfd, writeset);
835		} else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
836			if (CHANNEL_EFD_OUTPUT_ACTIVE(c))
837				debug2("channel %d: obuf_empty delayed efd %d/(%d)",
838				    c->self, c->efd, buffer_len(&c->extended));
839			else
840				chan_obuf_empty(c);
841		}
842	}
843	/** XXX check close conditions, too */
844	if (compat20 && c->efd != -1 &&
845	    !(c->istate == CHAN_INPUT_CLOSED && c->ostate == CHAN_OUTPUT_CLOSED)) {
846		if (c->extended_usage == CHAN_EXTENDED_WRITE &&
847		    buffer_len(&c->extended) > 0)
848			FD_SET(c->efd, writeset);
849		else if (c->efd != -1 && !(c->flags & CHAN_EOF_SENT) &&
850		    (c->extended_usage == CHAN_EXTENDED_READ ||
851		    c->extended_usage == CHAN_EXTENDED_IGNORE) &&
852		    buffer_len(&c->extended) < c->remote_window)
853			FD_SET(c->efd, readset);
854	}
855	/* XXX: What about efd? races? */
856}
857
858/* ARGSUSED */
859static void
860channel_pre_input_draining(Channel *c, fd_set *readset, fd_set *writeset)
861{
862	if (buffer_len(&c->input) == 0) {
863		packet_start(SSH_MSG_CHANNEL_CLOSE);
864		packet_put_int(c->remote_id);
865		packet_send();
866		c->type = SSH_CHANNEL_CLOSED;
867		debug2("channel %d: closing after input drain.", c->self);
868	}
869}
870
871/* ARGSUSED */
872static void
873channel_pre_output_draining(Channel *c, fd_set *readset, fd_set *writeset)
874{
875	if (buffer_len(&c->output) == 0)
876		chan_mark_dead(c);
877	else
878		FD_SET(c->sock, writeset);
879}
880
881/*
882 * This is a special state for X11 authentication spoofing.  An opened X11
883 * connection (when authentication spoofing is being done) remains in this
884 * state until the first packet has been completely read.  The authentication
885 * data in that packet is then substituted by the real data if it matches the
886 * fake data, and the channel is put into normal mode.
887 * XXX All this happens at the client side.
888 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
889 */
890static int
891x11_open_helper(Buffer *b)
892{
893	u_char *ucp;
894	u_int proto_len, data_len;
895
896	/* Check if the fixed size part of the packet is in buffer. */
897	if (buffer_len(b) < 12)
898		return 0;
899
900	/* Parse the lengths of variable-length fields. */
901	ucp = buffer_ptr(b);
902	if (ucp[0] == 0x42) {	/* Byte order MSB first. */
903		proto_len = 256 * ucp[6] + ucp[7];
904		data_len = 256 * ucp[8] + ucp[9];
905	} else if (ucp[0] == 0x6c) {	/* Byte order LSB first. */
906		proto_len = ucp[6] + 256 * ucp[7];
907		data_len = ucp[8] + 256 * ucp[9];
908	} else {
909		debug2("Initial X11 packet contains bad byte order byte: 0x%x",
910		    ucp[0]);
911		return -1;
912	}
913
914	/* Check if the whole packet is in buffer. */
915	if (buffer_len(b) <
916	    12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
917		return 0;
918
919	/* Check if authentication protocol matches. */
920	if (proto_len != strlen(x11_saved_proto) ||
921	    memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
922		debug2("X11 connection uses different authentication protocol.");
923		return -1;
924	}
925	/* Check if authentication data matches our fake data. */
926	if (data_len != x11_fake_data_len ||
927	    timingsafe_bcmp(ucp + 12 + ((proto_len + 3) & ~3),
928		x11_fake_data, x11_fake_data_len) != 0) {
929		debug2("X11 auth data does not match fake data.");
930		return -1;
931	}
932	/* Check fake data length */
933	if (x11_fake_data_len != x11_saved_data_len) {
934		error("X11 fake_data_len %d != saved_data_len %d",
935		    x11_fake_data_len, x11_saved_data_len);
936		return -1;
937	}
938	/*
939	 * Received authentication protocol and data match
940	 * our fake data. Substitute the fake data with real
941	 * data.
942	 */
943	memcpy(ucp + 12 + ((proto_len + 3) & ~3),
944	    x11_saved_data, x11_saved_data_len);
945	return 1;
946}
947
948static void
949channel_pre_x11_open_13(Channel *c, fd_set *readset, fd_set *writeset)
950{
951	int ret = x11_open_helper(&c->output);
952
953	if (ret == 1) {
954		/* Start normal processing for the channel. */
955		c->type = SSH_CHANNEL_OPEN;
956		channel_pre_open_13(c, readset, writeset);
957	} else if (ret == -1) {
958		/*
959		 * We have received an X11 connection that has bad
960		 * authentication information.
961		 */
962		logit("X11 connection rejected because of wrong authentication.");
963		buffer_clear(&c->input);
964		buffer_clear(&c->output);
965		channel_close_fd(&c->sock);
966		c->sock = -1;
967		c->type = SSH_CHANNEL_CLOSED;
968		packet_start(SSH_MSG_CHANNEL_CLOSE);
969		packet_put_int(c->remote_id);
970		packet_send();
971	}
972}
973
974static void
975channel_pre_x11_open(Channel *c, fd_set *readset, fd_set *writeset)
976{
977	int ret = x11_open_helper(&c->output);
978
979	/* c->force_drain = 1; */
980
981	if (ret == 1) {
982		c->type = SSH_CHANNEL_OPEN;
983		channel_pre_open(c, readset, writeset);
984	} else if (ret == -1) {
985		logit("X11 connection rejected because of wrong authentication.");
986		debug2("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
987		chan_read_failed(c);
988		buffer_clear(&c->input);
989		chan_ibuf_empty(c);
990		buffer_clear(&c->output);
991		/* for proto v1, the peer will send an IEOF */
992		if (compat20)
993			chan_write_failed(c);
994		else
995			c->type = SSH_CHANNEL_OPEN;
996		debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
997	}
998}
999
1000static void
1001channel_pre_mux_client(Channel *c, fd_set *readset, fd_set *writeset)
1002{
1003	if (c->istate == CHAN_INPUT_OPEN && !c->mux_pause &&
1004	    buffer_check_alloc(&c->input, CHAN_RBUF))
1005		FD_SET(c->rfd, readset);
1006	if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1007		/* clear buffer immediately (discard any partial packet) */
1008		buffer_clear(&c->input);
1009		chan_ibuf_empty(c);
1010		/* Start output drain. XXX just kill chan? */
1011		chan_rcvd_oclose(c);
1012	}
1013	if (c->ostate == CHAN_OUTPUT_OPEN ||
1014	    c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
1015		if (buffer_len(&c->output) > 0)
1016			FD_SET(c->wfd, writeset);
1017		else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN)
1018			chan_obuf_empty(c);
1019	}
1020}
1021
1022/* try to decode a socks4 header */
1023/* ARGSUSED */
1024static int
1025channel_decode_socks4(Channel *c, fd_set *readset, fd_set *writeset)
1026{
1027	char *p, *host;
1028	u_int len, have, i, found, need;
1029	char username[256];
1030	struct {
1031		u_int8_t version;
1032		u_int8_t command;
1033		u_int16_t dest_port;
1034		struct in_addr dest_addr;
1035	} s4_req, s4_rsp;
1036
1037	debug2("channel %d: decode socks4", c->self);
1038
1039	have = buffer_len(&c->input);
1040	len = sizeof(s4_req);
1041	if (have < len)
1042		return 0;
1043	p = buffer_ptr(&c->input);
1044
1045	need = 1;
1046	/* SOCKS4A uses an invalid IP address 0.0.0.x */
1047	if (p[4] == 0 && p[5] == 0 && p[6] == 0 && p[7] != 0) {
1048		debug2("channel %d: socks4a request", c->self);
1049		/* ... and needs an extra string (the hostname) */
1050		need = 2;
1051	}
1052	/* Check for terminating NUL on the string(s) */
1053	for (found = 0, i = len; i < have; i++) {
1054		if (p[i] == '\0') {
1055			found++;
1056			if (found == need)
1057				break;
1058		}
1059		if (i > 1024) {
1060			/* the peer is probably sending garbage */
1061			debug("channel %d: decode socks4: too long",
1062			    c->self);
1063			return -1;
1064		}
1065	}
1066	if (found < need)
1067		return 0;
1068	buffer_get(&c->input, (char *)&s4_req.version, 1);
1069	buffer_get(&c->input, (char *)&s4_req.command, 1);
1070	buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
1071	buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
1072	have = buffer_len(&c->input);
1073	p = buffer_ptr(&c->input);
1074	len = strlen(p);
1075	debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
1076	len++;					/* trailing '\0' */
1077	if (len > have)
1078		fatal("channel %d: decode socks4: len %d > have %d",
1079		    c->self, len, have);
1080	strlcpy(username, p, sizeof(username));
1081	buffer_consume(&c->input, len);
1082
1083	if (c->path != NULL) {
1084		xfree(c->path);
1085		c->path = NULL;
1086	}
1087	if (need == 1) {			/* SOCKS4: one string */
1088		host = inet_ntoa(s4_req.dest_addr);
1089		c->path = xstrdup(host);
1090	} else {				/* SOCKS4A: two strings */
1091		have = buffer_len(&c->input);
1092		p = buffer_ptr(&c->input);
1093		len = strlen(p);
1094		debug2("channel %d: decode socks4a: host %s/%d",
1095		    c->self, p, len);
1096		len++;				/* trailing '\0' */
1097		if (len > have)
1098			fatal("channel %d: decode socks4a: len %d > have %d",
1099			    c->self, len, have);
1100		if (len > NI_MAXHOST) {
1101			error("channel %d: hostname \"%.100s\" too long",
1102			    c->self, p);
1103			return -1;
1104		}
1105		c->path = xstrdup(p);
1106		buffer_consume(&c->input, len);
1107	}
1108	c->host_port = ntohs(s4_req.dest_port);
1109
1110	debug2("channel %d: dynamic request: socks4 host %s port %u command %u",
1111	    c->self, c->path, c->host_port, s4_req.command);
1112
1113	if (s4_req.command != 1) {
1114		debug("channel %d: cannot handle: %s cn %d",
1115		    c->self, need == 1 ? "SOCKS4" : "SOCKS4A", s4_req.command);
1116		return -1;
1117	}
1118	s4_rsp.version = 0;			/* vn: 0 for reply */
1119	s4_rsp.command = 90;			/* cd: req granted */
1120	s4_rsp.dest_port = 0;			/* ignored */
1121	s4_rsp.dest_addr.s_addr = INADDR_ANY;	/* ignored */
1122	buffer_append(&c->output, &s4_rsp, sizeof(s4_rsp));
1123	return 1;
1124}
1125
1126/* try to decode a socks5 header */
1127#define SSH_SOCKS5_AUTHDONE	0x1000
1128#define SSH_SOCKS5_NOAUTH	0x00
1129#define SSH_SOCKS5_IPV4		0x01
1130#define SSH_SOCKS5_DOMAIN	0x03
1131#define SSH_SOCKS5_IPV6		0x04
1132#define SSH_SOCKS5_CONNECT	0x01
1133#define SSH_SOCKS5_SUCCESS	0x00
1134
1135/* ARGSUSED */
1136static int
1137channel_decode_socks5(Channel *c, fd_set *readset, fd_set *writeset)
1138{
1139	struct {
1140		u_int8_t version;
1141		u_int8_t command;
1142		u_int8_t reserved;
1143		u_int8_t atyp;
1144	} s5_req, s5_rsp;
1145	u_int16_t dest_port;
1146	u_char *p, dest_addr[255+1], ntop[INET6_ADDRSTRLEN];
1147	u_int have, need, i, found, nmethods, addrlen, af;
1148
1149	debug2("channel %d: decode socks5", c->self);
1150	p = buffer_ptr(&c->input);
1151	if (p[0] != 0x05)
1152		return -1;
1153	have = buffer_len(&c->input);
1154	if (!(c->flags & SSH_SOCKS5_AUTHDONE)) {
1155		/* format: ver | nmethods | methods */
1156		if (have < 2)
1157			return 0;
1158		nmethods = p[1];
1159		if (have < nmethods + 2)
1160			return 0;
1161		/* look for method: "NO AUTHENTICATION REQUIRED" */
1162		for (found = 0, i = 2; i < nmethods + 2; i++) {
1163			if (p[i] == SSH_SOCKS5_NOAUTH) {
1164				found = 1;
1165				break;
1166			}
1167		}
1168		if (!found) {
1169			debug("channel %d: method SSH_SOCKS5_NOAUTH not found",
1170			    c->self);
1171			return -1;
1172		}
1173		buffer_consume(&c->input, nmethods + 2);
1174		buffer_put_char(&c->output, 0x05);		/* version */
1175		buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH);	/* method */
1176		FD_SET(c->sock, writeset);
1177		c->flags |= SSH_SOCKS5_AUTHDONE;
1178		debug2("channel %d: socks5 auth done", c->self);
1179		return 0;				/* need more */
1180	}
1181	debug2("channel %d: socks5 post auth", c->self);
1182	if (have < sizeof(s5_req)+1)
1183		return 0;			/* need more */
1184	memcpy(&s5_req, p, sizeof(s5_req));
1185	if (s5_req.version != 0x05 ||
1186	    s5_req.command != SSH_SOCKS5_CONNECT ||
1187	    s5_req.reserved != 0x00) {
1188		debug2("channel %d: only socks5 connect supported", c->self);
1189		return -1;
1190	}
1191	switch (s5_req.atyp){
1192	case SSH_SOCKS5_IPV4:
1193		addrlen = 4;
1194		af = AF_INET;
1195		break;
1196	case SSH_SOCKS5_DOMAIN:
1197		addrlen = p[sizeof(s5_req)];
1198		af = -1;
1199		break;
1200	case SSH_SOCKS5_IPV6:
1201		addrlen = 16;
1202		af = AF_INET6;
1203		break;
1204	default:
1205		debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp);
1206		return -1;
1207	}
1208	need = sizeof(s5_req) + addrlen + 2;
1209	if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1210		need++;
1211	if (have < need)
1212		return 0;
1213	buffer_consume(&c->input, sizeof(s5_req));
1214	if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1215		buffer_consume(&c->input, 1);    /* host string length */
1216	buffer_get(&c->input, (char *)&dest_addr, addrlen);
1217	buffer_get(&c->input, (char *)&dest_port, 2);
1218	dest_addr[addrlen] = '\0';
1219	if (c->path != NULL) {
1220		xfree(c->path);
1221		c->path = NULL;
1222	}
1223	if (s5_req.atyp == SSH_SOCKS5_DOMAIN) {
1224		if (addrlen >= NI_MAXHOST) {
1225			error("channel %d: dynamic request: socks5 hostname "
1226			    "\"%.100s\" too long", c->self, dest_addr);
1227			return -1;
1228		}
1229		c->path = xstrdup(dest_addr);
1230	} else {
1231		if (inet_ntop(af, dest_addr, ntop, sizeof(ntop)) == NULL)
1232			return -1;
1233		c->path = xstrdup(ntop);
1234	}
1235	c->host_port = ntohs(dest_port);
1236
1237	debug2("channel %d: dynamic request: socks5 host %s port %u command %u",
1238	    c->self, c->path, c->host_port, s5_req.command);
1239
1240	s5_rsp.version = 0x05;
1241	s5_rsp.command = SSH_SOCKS5_SUCCESS;
1242	s5_rsp.reserved = 0;			/* ignored */
1243	s5_rsp.atyp = SSH_SOCKS5_IPV4;
1244	((struct in_addr *)&dest_addr)->s_addr = INADDR_ANY;
1245	dest_port = 0;				/* ignored */
1246
1247	buffer_append(&c->output, &s5_rsp, sizeof(s5_rsp));
1248	buffer_append(&c->output, &dest_addr, sizeof(struct in_addr));
1249	buffer_append(&c->output, &dest_port, sizeof(dest_port));
1250	return 1;
1251}
1252
1253Channel *
1254channel_connect_stdio_fwd(const char *host_to_connect, u_short port_to_connect,
1255    int in, int out)
1256{
1257	Channel *c;
1258
1259	debug("channel_connect_stdio_fwd %s:%d", host_to_connect,
1260	    port_to_connect);
1261
1262	c = channel_new("stdio-forward", SSH_CHANNEL_OPENING, in, out,
1263	    -1, CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
1264	    0, "stdio-forward", /*nonblock*/0);
1265
1266	c->path = xstrdup(host_to_connect);
1267	c->host_port = port_to_connect;
1268	c->listening_port = 0;
1269	c->force_drain = 1;
1270
1271	channel_register_fds(c, in, out, -1, 0, 1, 0);
1272	port_open_helper(c, "direct-tcpip");
1273
1274	return c;
1275}
1276
1277/* dynamic port forwarding */
1278static void
1279channel_pre_dynamic(Channel *c, fd_set *readset, fd_set *writeset)
1280{
1281	u_char *p;
1282	u_int have;
1283	int ret;
1284
1285	have = buffer_len(&c->input);
1286	debug2("channel %d: pre_dynamic: have %d", c->self, have);
1287	/* buffer_dump(&c->input); */
1288	/* check if the fixed size part of the packet is in buffer. */
1289	if (have < 3) {
1290		/* need more */
1291		FD_SET(c->sock, readset);
1292		return;
1293	}
1294	/* try to guess the protocol */
1295	p = buffer_ptr(&c->input);
1296	switch (p[0]) {
1297	case 0x04:
1298		ret = channel_decode_socks4(c, readset, writeset);
1299		break;
1300	case 0x05:
1301		ret = channel_decode_socks5(c, readset, writeset);
1302		break;
1303	default:
1304		ret = -1;
1305		break;
1306	}
1307	if (ret < 0) {
1308		chan_mark_dead(c);
1309	} else if (ret == 0) {
1310		debug2("channel %d: pre_dynamic: need more", c->self);
1311		/* need more */
1312		FD_SET(c->sock, readset);
1313	} else {
1314		/* switch to the next state */
1315		c->type = SSH_CHANNEL_OPENING;
1316		port_open_helper(c, "direct-tcpip");
1317	}
1318}
1319
1320/* This is our fake X11 server socket. */
1321/* ARGSUSED */
1322static void
1323channel_post_x11_listener(Channel *c, fd_set *readset, fd_set *writeset)
1324{
1325	Channel *nc;
1326	struct sockaddr_storage addr;
1327	int newsock;
1328	socklen_t addrlen;
1329	char buf[16384], *remote_ipaddr;
1330	int remote_port;
1331
1332	if (FD_ISSET(c->sock, readset)) {
1333		debug("X11 connection requested.");
1334		addrlen = sizeof(addr);
1335		newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1336		if (c->single_connection) {
1337			debug2("single_connection: closing X11 listener.");
1338			channel_close_fd(&c->sock);
1339			chan_mark_dead(c);
1340		}
1341		if (newsock < 0) {
1342			error("accept: %.100s", strerror(errno));
1343			if (errno == EMFILE || errno == ENFILE)
1344				c->notbefore = time(NULL) + 1;
1345			return;
1346		}
1347		set_nodelay(newsock);
1348		remote_ipaddr = get_peer_ipaddr(newsock);
1349		remote_port = get_peer_port(newsock);
1350		snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1351		    remote_ipaddr, remote_port);
1352
1353		nc = channel_new("accepted x11 socket",
1354		    SSH_CHANNEL_OPENING, newsock, newsock, -1,
1355		    c->local_window_max, c->local_maxpacket, 0, buf, 1);
1356		if (compat20) {
1357			packet_start(SSH2_MSG_CHANNEL_OPEN);
1358			packet_put_cstring("x11");
1359			packet_put_int(nc->self);
1360			packet_put_int(nc->local_window_max);
1361			packet_put_int(nc->local_maxpacket);
1362			/* originator ipaddr and port */
1363			packet_put_cstring(remote_ipaddr);
1364			if (datafellows & SSH_BUG_X11FWD) {
1365				debug2("ssh2 x11 bug compat mode");
1366			} else {
1367				packet_put_int(remote_port);
1368			}
1369			packet_send();
1370		} else {
1371			packet_start(SSH_SMSG_X11_OPEN);
1372			packet_put_int(nc->self);
1373			if (packet_get_protocol_flags() &
1374			    SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1375				packet_put_cstring(buf);
1376			packet_send();
1377		}
1378		xfree(remote_ipaddr);
1379	}
1380}
1381
1382static void
1383port_open_helper(Channel *c, char *rtype)
1384{
1385	int direct;
1386	char buf[1024];
1387	char *remote_ipaddr = get_peer_ipaddr(c->sock);
1388	int remote_port = get_peer_port(c->sock);
1389
1390	if (remote_port == -1) {
1391		/* Fake addr/port to appease peers that validate it (Tectia) */
1392		xfree(remote_ipaddr);
1393		remote_ipaddr = xstrdup("127.0.0.1");
1394		remote_port = 65535;
1395	}
1396
1397	direct = (strcmp(rtype, "direct-tcpip") == 0);
1398
1399	snprintf(buf, sizeof buf,
1400	    "%s: listening port %d for %.100s port %d, "
1401	    "connect from %.200s port %d",
1402	    rtype, c->listening_port, c->path, c->host_port,
1403	    remote_ipaddr, remote_port);
1404
1405	xfree(c->remote_name);
1406	c->remote_name = xstrdup(buf);
1407
1408	if (compat20) {
1409		packet_start(SSH2_MSG_CHANNEL_OPEN);
1410		packet_put_cstring(rtype);
1411		packet_put_int(c->self);
1412		packet_put_int(c->local_window_max);
1413		packet_put_int(c->local_maxpacket);
1414		if (direct) {
1415			/* target host, port */
1416			packet_put_cstring(c->path);
1417			packet_put_int(c->host_port);
1418		} else {
1419			/* listen address, port */
1420			packet_put_cstring(c->path);
1421			packet_put_int(c->listening_port);
1422		}
1423		/* originator host and port */
1424		packet_put_cstring(remote_ipaddr);
1425		packet_put_int((u_int)remote_port);
1426		packet_send();
1427	} else {
1428		packet_start(SSH_MSG_PORT_OPEN);
1429		packet_put_int(c->self);
1430		packet_put_cstring(c->path);
1431		packet_put_int(c->host_port);
1432		if (packet_get_protocol_flags() &
1433		    SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1434			packet_put_cstring(c->remote_name);
1435		packet_send();
1436	}
1437	xfree(remote_ipaddr);
1438}
1439
1440static void
1441channel_set_reuseaddr(int fd)
1442{
1443	int on = 1;
1444
1445	/*
1446	 * Set socket options.
1447	 * Allow local port reuse in TIME_WAIT.
1448	 */
1449	if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1)
1450		error("setsockopt SO_REUSEADDR fd %d: %s", fd, strerror(errno));
1451}
1452
1453/*
1454 * This socket is listening for connections to a forwarded TCP/IP port.
1455 */
1456/* ARGSUSED */
1457static void
1458channel_post_port_listener(Channel *c, fd_set *readset, fd_set *writeset)
1459{
1460	Channel *nc;
1461	struct sockaddr_storage addr;
1462	int newsock, nextstate;
1463	socklen_t addrlen;
1464	char *rtype;
1465
1466	if (FD_ISSET(c->sock, readset)) {
1467		debug("Connection to port %d forwarding "
1468		    "to %.100s port %d requested.",
1469		    c->listening_port, c->path, c->host_port);
1470
1471		if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1472			nextstate = SSH_CHANNEL_OPENING;
1473			rtype = "forwarded-tcpip";
1474		} else {
1475			if (c->host_port == 0) {
1476				nextstate = SSH_CHANNEL_DYNAMIC;
1477				rtype = "dynamic-tcpip";
1478			} else {
1479				nextstate = SSH_CHANNEL_OPENING;
1480				rtype = "direct-tcpip";
1481			}
1482		}
1483
1484		addrlen = sizeof(addr);
1485		newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1486		if (newsock < 0) {
1487			error("accept: %.100s", strerror(errno));
1488			if (errno == EMFILE || errno == ENFILE)
1489				c->notbefore = time(NULL) + 1;
1490			return;
1491		}
1492		set_nodelay(newsock);
1493		nc = channel_new(rtype, nextstate, newsock, newsock, -1,
1494		    c->local_window_max, c->local_maxpacket, 0, rtype, 1);
1495		nc->listening_port = c->listening_port;
1496		nc->host_port = c->host_port;
1497		if (c->path != NULL)
1498			nc->path = xstrdup(c->path);
1499
1500		if (nextstate != SSH_CHANNEL_DYNAMIC)
1501			port_open_helper(nc, rtype);
1502	}
1503}
1504
1505/*
1506 * This is the authentication agent socket listening for connections from
1507 * clients.
1508 */
1509/* ARGSUSED */
1510static void
1511channel_post_auth_listener(Channel *c, fd_set *readset, fd_set *writeset)
1512{
1513	Channel *nc;
1514	int newsock;
1515	struct sockaddr_storage addr;
1516	socklen_t addrlen;
1517
1518	if (FD_ISSET(c->sock, readset)) {
1519		addrlen = sizeof(addr);
1520		newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1521		if (newsock < 0) {
1522			error("accept from auth socket: %.100s",
1523			    strerror(errno));
1524			if (errno == EMFILE || errno == ENFILE)
1525				c->notbefore = time(NULL) + 1;
1526			return;
1527		}
1528		nc = channel_new("accepted auth socket",
1529		    SSH_CHANNEL_OPENING, newsock, newsock, -1,
1530		    c->local_window_max, c->local_maxpacket,
1531		    0, "accepted auth socket", 1);
1532		if (compat20) {
1533			packet_start(SSH2_MSG_CHANNEL_OPEN);
1534			packet_put_cstring("auth-agent@openssh.com");
1535			packet_put_int(nc->self);
1536			packet_put_int(c->local_window_max);
1537			packet_put_int(c->local_maxpacket);
1538		} else {
1539			packet_start(SSH_SMSG_AGENT_OPEN);
1540			packet_put_int(nc->self);
1541		}
1542		packet_send();
1543	}
1544}
1545
1546/* ARGSUSED */
1547static void
1548channel_post_connecting(Channel *c, fd_set *readset, fd_set *writeset)
1549{
1550	int err = 0, sock;
1551	socklen_t sz = sizeof(err);
1552
1553	if (FD_ISSET(c->sock, writeset)) {
1554		if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) {
1555			err = errno;
1556			error("getsockopt SO_ERROR failed");
1557		}
1558		if (err == 0) {
1559			debug("channel %d: connected to %s port %d",
1560			    c->self, c->connect_ctx.host, c->connect_ctx.port);
1561			channel_connect_ctx_free(&c->connect_ctx);
1562			c->type = SSH_CHANNEL_OPEN;
1563			if (compat20) {
1564				packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1565				packet_put_int(c->remote_id);
1566				packet_put_int(c->self);
1567				packet_put_int(c->local_window);
1568				packet_put_int(c->local_maxpacket);
1569			} else {
1570				packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1571				packet_put_int(c->remote_id);
1572				packet_put_int(c->self);
1573			}
1574		} else {
1575			debug("channel %d: connection failed: %s",
1576			    c->self, strerror(err));
1577			/* Try next address, if any */
1578			if ((sock = connect_next(&c->connect_ctx)) > 0) {
1579				close(c->sock);
1580				c->sock = c->rfd = c->wfd = sock;
1581				channel_max_fd = channel_find_maxfd();
1582				return;
1583			}
1584			/* Exhausted all addresses */
1585			error("connect_to %.100s port %d: failed.",
1586			    c->connect_ctx.host, c->connect_ctx.port);
1587			channel_connect_ctx_free(&c->connect_ctx);
1588			if (compat20) {
1589				packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1590				packet_put_int(c->remote_id);
1591				packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1592				if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1593					packet_put_cstring(strerror(err));
1594					packet_put_cstring("");
1595				}
1596			} else {
1597				packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1598				packet_put_int(c->remote_id);
1599			}
1600			chan_mark_dead(c);
1601		}
1602		packet_send();
1603	}
1604}
1605
1606/* ARGSUSED */
1607static int
1608channel_handle_rfd(Channel *c, fd_set *readset, fd_set *writeset)
1609{
1610	char buf[CHAN_RBUF];
1611	int len, force;
1612
1613	force = c->isatty && c->detach_close && c->istate != CHAN_INPUT_CLOSED;
1614	if (c->rfd != -1 && (force || FD_ISSET(c->rfd, readset))) {
1615		errno = 0;
1616		len = read(c->rfd, buf, sizeof(buf));
1617		if (len < 0 && (errno == EINTR ||
1618		    ((errno == EAGAIN || errno == EWOULDBLOCK) && !force)))
1619			return 1;
1620#ifndef PTY_ZEROREAD
1621		if (len <= 0) {
1622#else
1623		if ((!c->isatty && len <= 0) ||
1624		    (c->isatty && (len < 0 || (len == 0 && errno != 0)))) {
1625#endif
1626			debug2("channel %d: read<=0 rfd %d len %d",
1627			    c->self, c->rfd, len);
1628			if (c->type != SSH_CHANNEL_OPEN) {
1629				debug2("channel %d: not open", c->self);
1630				chan_mark_dead(c);
1631				return -1;
1632			} else if (compat13) {
1633				buffer_clear(&c->output);
1634				c->type = SSH_CHANNEL_INPUT_DRAINING;
1635				debug2("channel %d: input draining.", c->self);
1636			} else {
1637				chan_read_failed(c);
1638			}
1639			return -1;
1640		}
1641		if (c->input_filter != NULL) {
1642			if (c->input_filter(c, buf, len) == -1) {
1643				debug2("channel %d: filter stops", c->self);
1644				chan_read_failed(c);
1645			}
1646		} else if (c->datagram) {
1647			buffer_put_string(&c->input, buf, len);
1648		} else {
1649			buffer_append(&c->input, buf, len);
1650		}
1651	}
1652	return 1;
1653}
1654
1655/* ARGSUSED */
1656static int
1657channel_handle_wfd(Channel *c, fd_set *readset, fd_set *writeset)
1658{
1659	struct termios tio;
1660	u_char *data = NULL, *buf;
1661	u_int dlen, olen = 0;
1662	int len;
1663
1664	/* Send buffered output data to the socket. */
1665	if (c->wfd != -1 &&
1666	    FD_ISSET(c->wfd, writeset) &&
1667	    buffer_len(&c->output) > 0) {
1668		olen = buffer_len(&c->output);
1669		if (c->output_filter != NULL) {
1670			if ((buf = c->output_filter(c, &data, &dlen)) == NULL) {
1671				debug2("channel %d: filter stops", c->self);
1672				if (c->type != SSH_CHANNEL_OPEN)
1673					chan_mark_dead(c);
1674				else
1675					chan_write_failed(c);
1676				return -1;
1677			}
1678		} else if (c->datagram) {
1679			buf = data = buffer_get_string(&c->output, &dlen);
1680		} else {
1681			buf = data = buffer_ptr(&c->output);
1682			dlen = buffer_len(&c->output);
1683		}
1684
1685		if (c->datagram) {
1686			/* ignore truncated writes, datagrams might get lost */
1687			len = write(c->wfd, buf, dlen);
1688			xfree(data);
1689			if (len < 0 && (errno == EINTR || errno == EAGAIN ||
1690			    errno == EWOULDBLOCK))
1691				return 1;
1692			if (len <= 0) {
1693				if (c->type != SSH_CHANNEL_OPEN)
1694					chan_mark_dead(c);
1695				else
1696					chan_write_failed(c);
1697				return -1;
1698			}
1699			goto out;
1700		}
1701#ifdef _AIX
1702		/* XXX: Later AIX versions can't push as much data to tty */
1703		if (compat20 && c->wfd_isatty)
1704			dlen = MIN(dlen, 8*1024);
1705#endif
1706
1707		len = write(c->wfd, buf, dlen);
1708		if (len < 0 &&
1709		    (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK))
1710			return 1;
1711		if (len <= 0) {
1712			if (c->type != SSH_CHANNEL_OPEN) {
1713				debug2("channel %d: not open", c->self);
1714				chan_mark_dead(c);
1715				return -1;
1716			} else if (compat13) {
1717				buffer_clear(&c->output);
1718				debug2("channel %d: input draining.", c->self);
1719				c->type = SSH_CHANNEL_INPUT_DRAINING;
1720			} else {
1721				chan_write_failed(c);
1722			}
1723			return -1;
1724		}
1725#ifndef BROKEN_TCGETATTR_ICANON
1726		if (compat20 && c->isatty && dlen >= 1 && buf[0] != '\r') {
1727			if (tcgetattr(c->wfd, &tio) == 0 &&
1728			    !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1729				/*
1730				 * Simulate echo to reduce the impact of
1731				 * traffic analysis. We need to match the
1732				 * size of a SSH2_MSG_CHANNEL_DATA message
1733				 * (4 byte channel id + buf)
1734				 */
1735				packet_send_ignore(4 + len);
1736				packet_send();
1737			}
1738		}
1739#endif
1740		buffer_consume(&c->output, len);
1741	}
1742 out:
1743	if (compat20 && olen > 0)
1744		c->local_consumed += olen - buffer_len(&c->output);
1745	return 1;
1746}
1747
1748static int
1749channel_handle_efd(Channel *c, fd_set *readset, fd_set *writeset)
1750{
1751	char buf[CHAN_RBUF];
1752	int len;
1753
1754/** XXX handle drain efd, too */
1755	if (c->efd != -1) {
1756		if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1757		    FD_ISSET(c->efd, writeset) &&
1758		    buffer_len(&c->extended) > 0) {
1759			len = write(c->efd, buffer_ptr(&c->extended),
1760			    buffer_len(&c->extended));
1761			debug2("channel %d: written %d to efd %d",
1762			    c->self, len, c->efd);
1763			if (len < 0 && (errno == EINTR || errno == EAGAIN ||
1764			    errno == EWOULDBLOCK))
1765				return 1;
1766			if (len <= 0) {
1767				debug2("channel %d: closing write-efd %d",
1768				    c->self, c->efd);
1769				channel_close_fd(&c->efd);
1770			} else {
1771				buffer_consume(&c->extended, len);
1772				c->local_consumed += len;
1773			}
1774		} else if (c->efd != -1 &&
1775		    (c->extended_usage == CHAN_EXTENDED_READ ||
1776		    c->extended_usage == CHAN_EXTENDED_IGNORE) &&
1777		    (c->detach_close || FD_ISSET(c->efd, readset))) {
1778			len = read(c->efd, buf, sizeof(buf));
1779			debug2("channel %d: read %d from efd %d",
1780			    c->self, len, c->efd);
1781			if (len < 0 && (errno == EINTR || ((errno == EAGAIN ||
1782			    errno == EWOULDBLOCK) && !c->detach_close)))
1783				return 1;
1784			if (len <= 0) {
1785				debug2("channel %d: closing read-efd %d",
1786				    c->self, c->efd);
1787				channel_close_fd(&c->efd);
1788			} else {
1789				if (c->extended_usage == CHAN_EXTENDED_IGNORE) {
1790					debug3("channel %d: discard efd",
1791					    c->self);
1792				} else
1793					buffer_append(&c->extended, buf, len);
1794			}
1795		}
1796	}
1797	return 1;
1798}
1799
1800static int
1801channel_check_window(Channel *c)
1802{
1803	if (c->type == SSH_CHANNEL_OPEN &&
1804	    !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1805	    ((c->local_window_max - c->local_window >
1806	    c->local_maxpacket*3) ||
1807	    c->local_window < c->local_window_max/2) &&
1808	    c->local_consumed > 0) {
1809		packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1810		packet_put_int(c->remote_id);
1811		packet_put_int(c->local_consumed);
1812		packet_send();
1813		debug2("channel %d: window %d sent adjust %d",
1814		    c->self, c->local_window,
1815		    c->local_consumed);
1816		c->local_window += c->local_consumed;
1817		c->local_consumed = 0;
1818	}
1819	return 1;
1820}
1821
1822static void
1823channel_post_open(Channel *c, fd_set *readset, fd_set *writeset)
1824{
1825	channel_handle_rfd(c, readset, writeset);
1826	channel_handle_wfd(c, readset, writeset);
1827	if (!compat20)
1828		return;
1829	channel_handle_efd(c, readset, writeset);
1830	channel_check_window(c);
1831}
1832
1833static u_int
1834read_mux(Channel *c, u_int need)
1835{
1836	char buf[CHAN_RBUF];
1837	int len;
1838	u_int rlen;
1839
1840	if (buffer_len(&c->input) < need) {
1841		rlen = need - buffer_len(&c->input);
1842		len = read(c->rfd, buf, MIN(rlen, CHAN_RBUF));
1843		if (len <= 0) {
1844			if (errno != EINTR && errno != EAGAIN) {
1845				debug2("channel %d: ctl read<=0 rfd %d len %d",
1846				    c->self, c->rfd, len);
1847				chan_read_failed(c);
1848				return 0;
1849			}
1850		} else
1851			buffer_append(&c->input, buf, len);
1852	}
1853	return buffer_len(&c->input);
1854}
1855
1856static void
1857channel_post_mux_client(Channel *c, fd_set *readset, fd_set *writeset)
1858{
1859	u_int need;
1860	ssize_t len;
1861
1862	if (!compat20)
1863		fatal("%s: entered with !compat20", __func__);
1864
1865	if (c->rfd != -1 && !c->mux_pause && FD_ISSET(c->rfd, readset) &&
1866	    (c->istate == CHAN_INPUT_OPEN ||
1867	    c->istate == CHAN_INPUT_WAIT_DRAIN)) {
1868		/*
1869		 * Don't not read past the precise end of packets to
1870		 * avoid disrupting fd passing.
1871		 */
1872		if (read_mux(c, 4) < 4) /* read header */
1873			return;
1874		need = get_u32(buffer_ptr(&c->input));
1875#define CHANNEL_MUX_MAX_PACKET	(256 * 1024)
1876		if (need > CHANNEL_MUX_MAX_PACKET) {
1877			debug2("channel %d: packet too big %u > %u",
1878			    c->self, CHANNEL_MUX_MAX_PACKET, need);
1879			chan_rcvd_oclose(c);
1880			return;
1881		}
1882		if (read_mux(c, need + 4) < need + 4) /* read body */
1883			return;
1884		if (c->mux_rcb(c) != 0) {
1885			debug("channel %d: mux_rcb failed", c->self);
1886			chan_mark_dead(c);
1887			return;
1888		}
1889	}
1890
1891	if (c->wfd != -1 && FD_ISSET(c->wfd, writeset) &&
1892	    buffer_len(&c->output) > 0) {
1893		len = write(c->wfd, buffer_ptr(&c->output),
1894		    buffer_len(&c->output));
1895		if (len < 0 && (errno == EINTR || errno == EAGAIN))
1896			return;
1897		if (len <= 0) {
1898			chan_mark_dead(c);
1899			return;
1900		}
1901		buffer_consume(&c->output, len);
1902	}
1903}
1904
1905static void
1906channel_post_mux_listener(Channel *c, fd_set *readset, fd_set *writeset)
1907{
1908	Channel *nc;
1909	struct sockaddr_storage addr;
1910	socklen_t addrlen;
1911	int newsock;
1912	uid_t euid;
1913	gid_t egid;
1914
1915	if (!FD_ISSET(c->sock, readset))
1916		return;
1917
1918	debug("multiplexing control connection");
1919
1920	/*
1921	 * Accept connection on control socket
1922	 */
1923	memset(&addr, 0, sizeof(addr));
1924	addrlen = sizeof(addr);
1925	if ((newsock = accept(c->sock, (struct sockaddr*)&addr,
1926	    &addrlen)) == -1) {
1927		error("%s accept: %s", __func__, strerror(errno));
1928		if (errno == EMFILE || errno == ENFILE)
1929			c->notbefore = time(NULL) + 1;
1930		return;
1931	}
1932
1933	if (getpeereid(newsock, &euid, &egid) < 0) {
1934		error("%s getpeereid failed: %s", __func__,
1935		    strerror(errno));
1936		close(newsock);
1937		return;
1938	}
1939	if ((euid != 0) && (getuid() != euid)) {
1940		error("multiplex uid mismatch: peer euid %u != uid %u",
1941		    (u_int)euid, (u_int)getuid());
1942		close(newsock);
1943		return;
1944	}
1945	nc = channel_new("multiplex client", SSH_CHANNEL_MUX_CLIENT,
1946	    newsock, newsock, -1, c->local_window_max,
1947	    c->local_maxpacket, 0, "mux-control", 1);
1948	nc->mux_rcb = c->mux_rcb;
1949	debug3("%s: new mux channel %d fd %d", __func__,
1950	    nc->self, nc->sock);
1951	/* establish state */
1952	nc->mux_rcb(nc);
1953	/* mux state transitions must not elicit protocol messages */
1954	nc->flags |= CHAN_LOCAL;
1955}
1956
1957/* ARGSUSED */
1958static void
1959channel_post_output_drain_13(Channel *c, fd_set *readset, fd_set *writeset)
1960{
1961	int len;
1962
1963	/* Send buffered output data to the socket. */
1964	if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1965		len = write(c->sock, buffer_ptr(&c->output),
1966			    buffer_len(&c->output));
1967		if (len <= 0)
1968			buffer_clear(&c->output);
1969		else
1970			buffer_consume(&c->output, len);
1971	}
1972}
1973
1974static void
1975channel_handler_init_20(void)
1976{
1977	channel_pre[SSH_CHANNEL_OPEN] =			&channel_pre_open;
1978	channel_pre[SSH_CHANNEL_X11_OPEN] =		&channel_pre_x11_open;
1979	channel_pre[SSH_CHANNEL_PORT_LISTENER] =	&channel_pre_listener;
1980	channel_pre[SSH_CHANNEL_RPORT_LISTENER] =	&channel_pre_listener;
1981	channel_pre[SSH_CHANNEL_X11_LISTENER] =		&channel_pre_listener;
1982	channel_pre[SSH_CHANNEL_AUTH_SOCKET] =		&channel_pre_listener;
1983	channel_pre[SSH_CHANNEL_CONNECTING] =		&channel_pre_connecting;
1984	channel_pre[SSH_CHANNEL_DYNAMIC] =		&channel_pre_dynamic;
1985	channel_pre[SSH_CHANNEL_MUX_LISTENER] =		&channel_pre_listener;
1986	channel_pre[SSH_CHANNEL_MUX_CLIENT] =		&channel_pre_mux_client;
1987
1988	channel_post[SSH_CHANNEL_OPEN] =		&channel_post_open;
1989	channel_post[SSH_CHANNEL_PORT_LISTENER] =	&channel_post_port_listener;
1990	channel_post[SSH_CHANNEL_RPORT_LISTENER] =	&channel_post_port_listener;
1991	channel_post[SSH_CHANNEL_X11_LISTENER] =	&channel_post_x11_listener;
1992	channel_post[SSH_CHANNEL_AUTH_SOCKET] =		&channel_post_auth_listener;
1993	channel_post[SSH_CHANNEL_CONNECTING] =		&channel_post_connecting;
1994	channel_post[SSH_CHANNEL_DYNAMIC] =		&channel_post_open;
1995	channel_post[SSH_CHANNEL_MUX_LISTENER] =	&channel_post_mux_listener;
1996	channel_post[SSH_CHANNEL_MUX_CLIENT] =		&channel_post_mux_client;
1997}
1998
1999static void
2000channel_handler_init_13(void)
2001{
2002	channel_pre[SSH_CHANNEL_OPEN] =			&channel_pre_open_13;
2003	channel_pre[SSH_CHANNEL_X11_OPEN] =		&channel_pre_x11_open_13;
2004	channel_pre[SSH_CHANNEL_X11_LISTENER] =		&channel_pre_listener;
2005	channel_pre[SSH_CHANNEL_PORT_LISTENER] =	&channel_pre_listener;
2006	channel_pre[SSH_CHANNEL_AUTH_SOCKET] =		&channel_pre_listener;
2007	channel_pre[SSH_CHANNEL_INPUT_DRAINING] =	&channel_pre_input_draining;
2008	channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] =	&channel_pre_output_draining;
2009	channel_pre[SSH_CHANNEL_CONNECTING] =		&channel_pre_connecting;
2010	channel_pre[SSH_CHANNEL_DYNAMIC] =		&channel_pre_dynamic;
2011
2012	channel_post[SSH_CHANNEL_OPEN] =		&channel_post_open;
2013	channel_post[SSH_CHANNEL_X11_LISTENER] =	&channel_post_x11_listener;
2014	channel_post[SSH_CHANNEL_PORT_LISTENER] =	&channel_post_port_listener;
2015	channel_post[SSH_CHANNEL_AUTH_SOCKET] =		&channel_post_auth_listener;
2016	channel_post[SSH_CHANNEL_OUTPUT_DRAINING] =	&channel_post_output_drain_13;
2017	channel_post[SSH_CHANNEL_CONNECTING] =		&channel_post_connecting;
2018	channel_post[SSH_CHANNEL_DYNAMIC] =		&channel_post_open;
2019}
2020
2021static void
2022channel_handler_init_15(void)
2023{
2024	channel_pre[SSH_CHANNEL_OPEN] =			&channel_pre_open;
2025	channel_pre[SSH_CHANNEL_X11_OPEN] =		&channel_pre_x11_open;
2026	channel_pre[SSH_CHANNEL_X11_LISTENER] =		&channel_pre_listener;
2027	channel_pre[SSH_CHANNEL_PORT_LISTENER] =	&channel_pre_listener;
2028	channel_pre[SSH_CHANNEL_AUTH_SOCKET] =		&channel_pre_listener;
2029	channel_pre[SSH_CHANNEL_CONNECTING] =		&channel_pre_connecting;
2030	channel_pre[SSH_CHANNEL_DYNAMIC] =		&channel_pre_dynamic;
2031
2032	channel_post[SSH_CHANNEL_X11_LISTENER] =	&channel_post_x11_listener;
2033	channel_post[SSH_CHANNEL_PORT_LISTENER] =	&channel_post_port_listener;
2034	channel_post[SSH_CHANNEL_AUTH_SOCKET] =		&channel_post_auth_listener;
2035	channel_post[SSH_CHANNEL_OPEN] =		&channel_post_open;
2036	channel_post[SSH_CHANNEL_CONNECTING] =		&channel_post_connecting;
2037	channel_post[SSH_CHANNEL_DYNAMIC] =		&channel_post_open;
2038}
2039
2040static void
2041channel_handler_init(void)
2042{
2043	int i;
2044
2045	for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
2046		channel_pre[i] = NULL;
2047		channel_post[i] = NULL;
2048	}
2049	if (compat20)
2050		channel_handler_init_20();
2051	else if (compat13)
2052		channel_handler_init_13();
2053	else
2054		channel_handler_init_15();
2055}
2056
2057/* gc dead channels */
2058static void
2059channel_garbage_collect(Channel *c)
2060{
2061	if (c == NULL)
2062		return;
2063	if (c->detach_user != NULL) {
2064		if (!chan_is_dead(c, c->detach_close))
2065			return;
2066		debug2("channel %d: gc: notify user", c->self);
2067		c->detach_user(c->self, NULL);
2068		/* if we still have a callback */
2069		if (c->detach_user != NULL)
2070			return;
2071		debug2("channel %d: gc: user detached", c->self);
2072	}
2073	if (!chan_is_dead(c, 1))
2074		return;
2075	debug2("channel %d: garbage collecting", c->self);
2076	channel_free(c);
2077}
2078
2079static void
2080channel_handler(chan_fn *ftab[], fd_set *readset, fd_set *writeset,
2081    time_t *unpause_secs)
2082{
2083	static int did_init = 0;
2084	u_int i, oalloc;
2085	Channel *c;
2086	time_t now;
2087
2088	if (!did_init) {
2089		channel_handler_init();
2090		did_init = 1;
2091	}
2092	now = time(NULL);
2093	if (unpause_secs != NULL)
2094		*unpause_secs = 0;
2095	for (i = 0, oalloc = channels_alloc; i < oalloc; i++) {
2096		c = channels[i];
2097		if (c == NULL)
2098			continue;
2099		if (c->delayed) {
2100			if (ftab == channel_pre)
2101				c->delayed = 0;
2102			else
2103				continue;
2104		}
2105		if (ftab[c->type] != NULL) {
2106			/*
2107			 * Run handlers that are not paused.
2108			 */
2109			if (c->notbefore <= now)
2110				(*ftab[c->type])(c, readset, writeset);
2111			else if (unpause_secs != NULL) {
2112				/*
2113				 * Collect the time that the earliest
2114				 * channel comes off pause.
2115				 */
2116				debug3("%s: chan %d: skip for %d more seconds",
2117				    __func__, c->self,
2118				    (int)(c->notbefore - now));
2119				if (*unpause_secs == 0 ||
2120				    (c->notbefore - now) < *unpause_secs)
2121					*unpause_secs = c->notbefore - now;
2122			}
2123		}
2124		channel_garbage_collect(c);
2125	}
2126	if (unpause_secs != NULL && *unpause_secs != 0)
2127		debug3("%s: first channel unpauses in %d seconds",
2128		    __func__, (int)*unpause_secs);
2129}
2130
2131/*
2132 * Allocate/update select bitmasks and add any bits relevant to channels in
2133 * select bitmasks.
2134 */
2135void
2136channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
2137    u_int *nallocp, time_t *minwait_secs, int rekeying)
2138{
2139	u_int n, sz, nfdset;
2140
2141	n = MAX(*maxfdp, channel_max_fd);
2142
2143	nfdset = howmany(n+1, NFDBITS);
2144	/* Explicitly test here, because xrealloc isn't always called */
2145	if (nfdset && SIZE_T_MAX / nfdset < sizeof(fd_mask))
2146		fatal("channel_prepare_select: max_fd (%d) is too large", n);
2147	sz = nfdset * sizeof(fd_mask);
2148
2149	/* perhaps check sz < nalloc/2 and shrink? */
2150	if (*readsetp == NULL || sz > *nallocp) {
2151		*readsetp = xrealloc(*readsetp, nfdset, sizeof(fd_mask));
2152		*writesetp = xrealloc(*writesetp, nfdset, sizeof(fd_mask));
2153		*nallocp = sz;
2154	}
2155	*maxfdp = n;
2156	memset(*readsetp, 0, sz);
2157	memset(*writesetp, 0, sz);
2158
2159	if (!rekeying)
2160		channel_handler(channel_pre, *readsetp, *writesetp,
2161		    minwait_secs);
2162}
2163
2164/*
2165 * After select, perform any appropriate operations for channels which have
2166 * events pending.
2167 */
2168void
2169channel_after_select(fd_set *readset, fd_set *writeset)
2170{
2171	channel_handler(channel_post, readset, writeset, NULL);
2172}
2173
2174
2175/* If there is data to send to the connection, enqueue some of it now. */
2176void
2177channel_output_poll(void)
2178{
2179	Channel *c;
2180	u_int i, len;
2181
2182	for (i = 0; i < channels_alloc; i++) {
2183		c = channels[i];
2184		if (c == NULL)
2185			continue;
2186
2187		/*
2188		 * We are only interested in channels that can have buffered
2189		 * incoming data.
2190		 */
2191		if (compat13) {
2192			if (c->type != SSH_CHANNEL_OPEN &&
2193			    c->type != SSH_CHANNEL_INPUT_DRAINING)
2194				continue;
2195		} else {
2196			if (c->type != SSH_CHANNEL_OPEN)
2197				continue;
2198		}
2199		if (compat20 &&
2200		    (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
2201			/* XXX is this true? */
2202			debug3("channel %d: will not send data after close", c->self);
2203			continue;
2204		}
2205
2206		/* Get the amount of buffered data for this channel. */
2207		if ((c->istate == CHAN_INPUT_OPEN ||
2208		    c->istate == CHAN_INPUT_WAIT_DRAIN) &&
2209		    (len = buffer_len(&c->input)) > 0) {
2210			if (c->datagram) {
2211				if (len > 0) {
2212					u_char *data;
2213					u_int dlen;
2214
2215					data = buffer_get_string(&c->input,
2216					    &dlen);
2217					if (dlen > c->remote_window ||
2218					    dlen > c->remote_maxpacket) {
2219						debug("channel %d: datagram "
2220						    "too big for channel",
2221						    c->self);
2222						xfree(data);
2223						continue;
2224					}
2225					packet_start(SSH2_MSG_CHANNEL_DATA);
2226					packet_put_int(c->remote_id);
2227					packet_put_string(data, dlen);
2228					packet_send();
2229					c->remote_window -= dlen + 4;
2230					xfree(data);
2231				}
2232				continue;
2233			}
2234			/*
2235			 * Send some data for the other side over the secure
2236			 * connection.
2237			 */
2238			if (compat20) {
2239				if (len > c->remote_window)
2240					len = c->remote_window;
2241				if (len > c->remote_maxpacket)
2242					len = c->remote_maxpacket;
2243			} else {
2244				if (packet_is_interactive()) {
2245					if (len > 1024)
2246						len = 512;
2247				} else {
2248					/* Keep the packets at reasonable size. */
2249					if (len > packet_get_maxsize()/2)
2250						len = packet_get_maxsize()/2;
2251				}
2252			}
2253			if (len > 0) {
2254				packet_start(compat20 ?
2255				    SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
2256				packet_put_int(c->remote_id);
2257				packet_put_string(buffer_ptr(&c->input), len);
2258				packet_send();
2259				buffer_consume(&c->input, len);
2260				c->remote_window -= len;
2261			}
2262		} else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
2263			if (compat13)
2264				fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
2265			/*
2266			 * input-buffer is empty and read-socket shutdown:
2267			 * tell peer, that we will not send more data: send IEOF.
2268			 * hack for extended data: delay EOF if EFD still in use.
2269			 */
2270			if (CHANNEL_EFD_INPUT_ACTIVE(c))
2271				debug2("channel %d: ibuf_empty delayed efd %d/(%d)",
2272				    c->self, c->efd, buffer_len(&c->extended));
2273			else
2274				chan_ibuf_empty(c);
2275		}
2276		/* Send extended data, i.e. stderr */
2277		if (compat20 &&
2278		    !(c->flags & CHAN_EOF_SENT) &&
2279		    c->remote_window > 0 &&
2280		    (len = buffer_len(&c->extended)) > 0 &&
2281		    c->extended_usage == CHAN_EXTENDED_READ) {
2282			debug2("channel %d: rwin %u elen %u euse %d",
2283			    c->self, c->remote_window, buffer_len(&c->extended),
2284			    c->extended_usage);
2285			if (len > c->remote_window)
2286				len = c->remote_window;
2287			if (len > c->remote_maxpacket)
2288				len = c->remote_maxpacket;
2289			packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
2290			packet_put_int(c->remote_id);
2291			packet_put_int(SSH2_EXTENDED_DATA_STDERR);
2292			packet_put_string(buffer_ptr(&c->extended), len);
2293			packet_send();
2294			buffer_consume(&c->extended, len);
2295			c->remote_window -= len;
2296			debug2("channel %d: sent ext data %d", c->self, len);
2297		}
2298	}
2299}
2300
2301
2302/* -- protocol input */
2303
2304/* ARGSUSED */
2305void
2306channel_input_data(int type, u_int32_t seq, void *ctxt)
2307{
2308	int id;
2309	char *data;
2310	u_int data_len, win_len;
2311	Channel *c;
2312
2313	/* Get the channel number and verify it. */
2314	id = packet_get_int();
2315	c = channel_lookup(id);
2316	if (c == NULL)
2317		packet_disconnect("Received data for nonexistent channel %d.", id);
2318
2319	/* Ignore any data for non-open channels (might happen on close) */
2320	if (c->type != SSH_CHANNEL_OPEN &&
2321	    c->type != SSH_CHANNEL_X11_OPEN)
2322		return;
2323
2324	/* Get the data. */
2325	data = packet_get_string_ptr(&data_len);
2326	win_len = data_len;
2327	if (c->datagram)
2328		win_len += 4;  /* string length header */
2329
2330	/*
2331	 * Ignore data for protocol > 1.3 if output end is no longer open.
2332	 * For protocol 2 the sending side is reducing its window as it sends
2333	 * data, so we must 'fake' consumption of the data in order to ensure
2334	 * that window updates are sent back.  Otherwise the connection might
2335	 * deadlock.
2336	 */
2337	if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) {
2338		if (compat20) {
2339			c->local_window -= win_len;
2340			c->local_consumed += win_len;
2341		}
2342		return;
2343	}
2344
2345	if (compat20) {
2346		if (win_len > c->local_maxpacket) {
2347			logit("channel %d: rcvd big packet %d, maxpack %d",
2348			    c->self, win_len, c->local_maxpacket);
2349		}
2350		if (win_len > c->local_window) {
2351			logit("channel %d: rcvd too much data %d, win %d",
2352			    c->self, win_len, c->local_window);
2353			return;
2354		}
2355		c->local_window -= win_len;
2356	}
2357	if (c->datagram)
2358		buffer_put_string(&c->output, data, data_len);
2359	else
2360		buffer_append(&c->output, data, data_len);
2361	packet_check_eom();
2362}
2363
2364/* ARGSUSED */
2365void
2366channel_input_extended_data(int type, u_int32_t seq, void *ctxt)
2367{
2368	int id;
2369	char *data;
2370	u_int data_len, tcode;
2371	Channel *c;
2372
2373	/* Get the channel number and verify it. */
2374	id = packet_get_int();
2375	c = channel_lookup(id);
2376
2377	if (c == NULL)
2378		packet_disconnect("Received extended_data for bad channel %d.", id);
2379	if (c->type != SSH_CHANNEL_OPEN) {
2380		logit("channel %d: ext data for non open", id);
2381		return;
2382	}
2383	if (c->flags & CHAN_EOF_RCVD) {
2384		if (datafellows & SSH_BUG_EXTEOF)
2385			debug("channel %d: accepting ext data after eof", id);
2386		else
2387			packet_disconnect("Received extended_data after EOF "
2388			    "on channel %d.", id);
2389	}
2390	tcode = packet_get_int();
2391	if (c->efd == -1 ||
2392	    c->extended_usage != CHAN_EXTENDED_WRITE ||
2393	    tcode != SSH2_EXTENDED_DATA_STDERR) {
2394		logit("channel %d: bad ext data", c->self);
2395		return;
2396	}
2397	data = packet_get_string(&data_len);
2398	packet_check_eom();
2399	if (data_len > c->local_window) {
2400		logit("channel %d: rcvd too much extended_data %d, win %d",
2401		    c->self, data_len, c->local_window);
2402		xfree(data);
2403		return;
2404	}
2405	debug2("channel %d: rcvd ext data %d", c->self, data_len);
2406	c->local_window -= data_len;
2407	buffer_append(&c->extended, data, data_len);
2408	xfree(data);
2409}
2410
2411/* ARGSUSED */
2412void
2413channel_input_ieof(int type, u_int32_t seq, void *ctxt)
2414{
2415	int id;
2416	Channel *c;
2417
2418	id = packet_get_int();
2419	packet_check_eom();
2420	c = channel_lookup(id);
2421	if (c == NULL)
2422		packet_disconnect("Received ieof for nonexistent channel %d.", id);
2423	chan_rcvd_ieof(c);
2424
2425	/* XXX force input close */
2426	if (c->force_drain && c->istate == CHAN_INPUT_OPEN) {
2427		debug("channel %d: FORCE input drain", c->self);
2428		c->istate = CHAN_INPUT_WAIT_DRAIN;
2429		if (buffer_len(&c->input) == 0)
2430			chan_ibuf_empty(c);
2431	}
2432
2433}
2434
2435/* ARGSUSED */
2436void
2437channel_input_close(int type, u_int32_t seq, void *ctxt)
2438{
2439	int id;
2440	Channel *c;
2441
2442	id = packet_get_int();
2443	packet_check_eom();
2444	c = channel_lookup(id);
2445	if (c == NULL)
2446		packet_disconnect("Received close for nonexistent channel %d.", id);
2447
2448	/*
2449	 * Send a confirmation that we have closed the channel and no more
2450	 * data is coming for it.
2451	 */
2452	packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
2453	packet_put_int(c->remote_id);
2454	packet_send();
2455
2456	/*
2457	 * If the channel is in closed state, we have sent a close request,
2458	 * and the other side will eventually respond with a confirmation.
2459	 * Thus, we cannot free the channel here, because then there would be
2460	 * no-one to receive the confirmation.  The channel gets freed when
2461	 * the confirmation arrives.
2462	 */
2463	if (c->type != SSH_CHANNEL_CLOSED) {
2464		/*
2465		 * Not a closed channel - mark it as draining, which will
2466		 * cause it to be freed later.
2467		 */
2468		buffer_clear(&c->input);
2469		c->type = SSH_CHANNEL_OUTPUT_DRAINING;
2470	}
2471}
2472
2473/* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
2474/* ARGSUSED */
2475void
2476channel_input_oclose(int type, u_int32_t seq, void *ctxt)
2477{
2478	int id = packet_get_int();
2479	Channel *c = channel_lookup(id);
2480
2481	packet_check_eom();
2482	if (c == NULL)
2483		packet_disconnect("Received oclose for nonexistent channel %d.", id);
2484	chan_rcvd_oclose(c);
2485}
2486
2487/* ARGSUSED */
2488void
2489channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt)
2490{
2491	int id = packet_get_int();
2492	Channel *c = channel_lookup(id);
2493
2494	packet_check_eom();
2495	if (c == NULL)
2496		packet_disconnect("Received close confirmation for "
2497		    "out-of-range channel %d.", id);
2498	if (c->type != SSH_CHANNEL_CLOSED)
2499		packet_disconnect("Received close confirmation for "
2500		    "non-closed channel %d (type %d).", id, c->type);
2501	channel_free(c);
2502}
2503
2504/* ARGSUSED */
2505void
2506channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt)
2507{
2508	int id, remote_id;
2509	Channel *c;
2510
2511	id = packet_get_int();
2512	c = channel_lookup(id);
2513
2514	if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2515		packet_disconnect("Received open confirmation for "
2516		    "non-opening channel %d.", id);
2517	remote_id = packet_get_int();
2518	/* Record the remote channel number and mark that the channel is now open. */
2519	c->remote_id = remote_id;
2520	c->type = SSH_CHANNEL_OPEN;
2521
2522	if (compat20) {
2523		c->remote_window = packet_get_int();
2524		c->remote_maxpacket = packet_get_int();
2525		if (c->open_confirm) {
2526			debug2("callback start");
2527			c->open_confirm(c->self, 1, c->open_confirm_ctx);
2528			debug2("callback done");
2529		}
2530		debug2("channel %d: open confirm rwindow %u rmax %u", c->self,
2531		    c->remote_window, c->remote_maxpacket);
2532	}
2533	packet_check_eom();
2534}
2535
2536static char *
2537reason2txt(int reason)
2538{
2539	switch (reason) {
2540	case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
2541		return "administratively prohibited";
2542	case SSH2_OPEN_CONNECT_FAILED:
2543		return "connect failed";
2544	case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
2545		return "unknown channel type";
2546	case SSH2_OPEN_RESOURCE_SHORTAGE:
2547		return "resource shortage";
2548	}
2549	return "unknown reason";
2550}
2551
2552/* ARGSUSED */
2553void
2554channel_input_open_failure(int type, u_int32_t seq, void *ctxt)
2555{
2556	int id, reason;
2557	char *msg = NULL, *lang = NULL;
2558	Channel *c;
2559
2560	id = packet_get_int();
2561	c = channel_lookup(id);
2562
2563	if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2564		packet_disconnect("Received open failure for "
2565		    "non-opening channel %d.", id);
2566	if (compat20) {
2567		reason = packet_get_int();
2568		if (!(datafellows & SSH_BUG_OPENFAILURE)) {
2569			msg  = packet_get_string(NULL);
2570			lang = packet_get_string(NULL);
2571		}
2572		logit("channel %d: open failed: %s%s%s", id,
2573		    reason2txt(reason), msg ? ": ": "", msg ? msg : "");
2574		if (msg != NULL)
2575			xfree(msg);
2576		if (lang != NULL)
2577			xfree(lang);
2578		if (c->open_confirm) {
2579			debug2("callback start");
2580			c->open_confirm(c->self, 0, c->open_confirm_ctx);
2581			debug2("callback done");
2582		}
2583	}
2584	packet_check_eom();
2585	/* Schedule the channel for cleanup/deletion. */
2586	chan_mark_dead(c);
2587}
2588
2589/* ARGSUSED */
2590void
2591channel_input_window_adjust(int type, u_int32_t seq, void *ctxt)
2592{
2593	Channel *c;
2594	int id;
2595	u_int adjust;
2596
2597	if (!compat20)
2598		return;
2599
2600	/* Get the channel number and verify it. */
2601	id = packet_get_int();
2602	c = channel_lookup(id);
2603
2604	if (c == NULL) {
2605		logit("Received window adjust for non-open channel %d.", id);
2606		return;
2607	}
2608	adjust = packet_get_int();
2609	packet_check_eom();
2610	debug2("channel %d: rcvd adjust %u", id, adjust);
2611	c->remote_window += adjust;
2612}
2613
2614/* ARGSUSED */
2615void
2616channel_input_port_open(int type, u_int32_t seq, void *ctxt)
2617{
2618	Channel *c = NULL;
2619	u_short host_port;
2620	char *host, *originator_string;
2621	int remote_id;
2622
2623	remote_id = packet_get_int();
2624	host = packet_get_string(NULL);
2625	host_port = packet_get_int();
2626
2627	if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2628		originator_string = packet_get_string(NULL);
2629	} else {
2630		originator_string = xstrdup("unknown (remote did not supply name)");
2631	}
2632	packet_check_eom();
2633	c = channel_connect_to(host, host_port,
2634	    "connected socket", originator_string);
2635	xfree(originator_string);
2636	xfree(host);
2637	if (c == NULL) {
2638		packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2639		packet_put_int(remote_id);
2640		packet_send();
2641	} else
2642		c->remote_id = remote_id;
2643}
2644
2645/* ARGSUSED */
2646void
2647channel_input_status_confirm(int type, u_int32_t seq, void *ctxt)
2648{
2649	Channel *c;
2650	struct channel_confirm *cc;
2651	int id;
2652
2653	/* Reset keepalive timeout */
2654	packet_set_alive_timeouts(0);
2655
2656	id = packet_get_int();
2657	packet_check_eom();
2658
2659	debug2("channel_input_status_confirm: type %d id %d", type, id);
2660
2661	if ((c = channel_lookup(id)) == NULL) {
2662		logit("channel_input_status_confirm: %d: unknown", id);
2663		return;
2664	}
2665	;
2666	if ((cc = TAILQ_FIRST(&c->status_confirms)) == NULL)
2667		return;
2668	cc->cb(type, c, cc->ctx);
2669	TAILQ_REMOVE(&c->status_confirms, cc, entry);
2670	bzero(cc, sizeof(*cc));
2671	xfree(cc);
2672}
2673
2674/* -- tcp forwarding */
2675
2676void
2677channel_set_af(int af)
2678{
2679	IPv4or6 = af;
2680}
2681
2682
2683/*
2684 * Determine whether or not a port forward listens to loopback, the
2685 * specified address or wildcard. On the client, a specified bind
2686 * address will always override gateway_ports. On the server, a
2687 * gateway_ports of 1 (``yes'') will override the client's specification
2688 * and force a wildcard bind, whereas a value of 2 (``clientspecified'')
2689 * will bind to whatever address the client asked for.
2690 *
2691 * Special-case listen_addrs are:
2692 *
2693 * "0.0.0.0"               -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR
2694 * "" (empty string), "*"  -> wildcard v4/v6
2695 * "localhost"             -> loopback v4/v6
2696 */
2697static const char *
2698channel_fwd_bind_addr(const char *listen_addr, int *wildcardp,
2699    int is_client, int gateway_ports)
2700{
2701	const char *addr = NULL;
2702	int wildcard = 0;
2703
2704	if (listen_addr == NULL) {
2705		/* No address specified: default to gateway_ports setting */
2706		if (gateway_ports)
2707			wildcard = 1;
2708	} else if (gateway_ports || is_client) {
2709		if (((datafellows & SSH_OLD_FORWARD_ADDR) &&
2710		    strcmp(listen_addr, "0.0.0.0") == 0 && is_client == 0) ||
2711		    *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 ||
2712		    (!is_client && gateway_ports == 1))
2713			wildcard = 1;
2714		else if (strcmp(listen_addr, "localhost") != 0)
2715			addr = listen_addr;
2716	}
2717	if (wildcardp != NULL)
2718		*wildcardp = wildcard;
2719	return addr;
2720}
2721
2722static int
2723channel_setup_fwd_listener(int type, const char *listen_addr,
2724    u_short listen_port, int *allocated_listen_port,
2725    const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2726{
2727	Channel *c;
2728	int sock, r, success = 0, wildcard = 0, is_client;
2729	struct addrinfo hints, *ai, *aitop;
2730	const char *host, *addr;
2731	char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2732	in_port_t *lport_p;
2733
2734	host = (type == SSH_CHANNEL_RPORT_LISTENER) ?
2735	    listen_addr : host_to_connect;
2736	is_client = (type == SSH_CHANNEL_PORT_LISTENER);
2737
2738	if (host == NULL) {
2739		error("No forward host name.");
2740		return 0;
2741	}
2742	if (strlen(host) >= NI_MAXHOST) {
2743		error("Forward host name too long.");
2744		return 0;
2745	}
2746
2747	/* Determine the bind address, cf. channel_fwd_bind_addr() comment */
2748	addr = channel_fwd_bind_addr(listen_addr, &wildcard,
2749	    is_client, gateway_ports);
2750	debug3("channel_setup_fwd_listener: type %d wildcard %d addr %s",
2751	    type, wildcard, (addr == NULL) ? "NULL" : addr);
2752
2753	/*
2754	 * getaddrinfo returns a loopback address if the hostname is
2755	 * set to NULL and hints.ai_flags is not AI_PASSIVE
2756	 */
2757	memset(&hints, 0, sizeof(hints));
2758	hints.ai_family = IPv4or6;
2759	hints.ai_flags = wildcard ? AI_PASSIVE : 0;
2760	hints.ai_socktype = SOCK_STREAM;
2761	snprintf(strport, sizeof strport, "%d", listen_port);
2762	if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) {
2763		if (addr == NULL) {
2764			/* This really shouldn't happen */
2765			packet_disconnect("getaddrinfo: fatal error: %s",
2766			    ssh_gai_strerror(r));
2767		} else {
2768			error("channel_setup_fwd_listener: "
2769			    "getaddrinfo(%.64s): %s", addr,
2770			    ssh_gai_strerror(r));
2771		}
2772		return 0;
2773	}
2774	if (allocated_listen_port != NULL)
2775		*allocated_listen_port = 0;
2776	for (ai = aitop; ai; ai = ai->ai_next) {
2777		switch (ai->ai_family) {
2778		case AF_INET:
2779			lport_p = &((struct sockaddr_in *)ai->ai_addr)->
2780			    sin_port;
2781			break;
2782		case AF_INET6:
2783			lport_p = &((struct sockaddr_in6 *)ai->ai_addr)->
2784			    sin6_port;
2785			break;
2786		default:
2787			continue;
2788		}
2789		/*
2790		 * If allocating a port for -R forwards, then use the
2791		 * same port for all address families.
2792		 */
2793		if (type == SSH_CHANNEL_RPORT_LISTENER && listen_port == 0 &&
2794		    allocated_listen_port != NULL && *allocated_listen_port > 0)
2795			*lport_p = htons(*allocated_listen_port);
2796
2797		if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2798		    strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2799			error("channel_setup_fwd_listener: getnameinfo failed");
2800			continue;
2801		}
2802		/* Create a port to listen for the host. */
2803		sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2804		if (sock < 0) {
2805			/* this is no error since kernel may not support ipv6 */
2806			verbose("socket: %.100s", strerror(errno));
2807			continue;
2808		}
2809
2810		channel_set_reuseaddr(sock);
2811		if (ai->ai_family == AF_INET6)
2812			sock_set_v6only(sock);
2813
2814		debug("Local forwarding listening on %s port %s.",
2815		    ntop, strport);
2816
2817		/* Bind the socket to the address. */
2818		if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2819			/* address can be in use ipv6 address is already bound */
2820			if (!ai->ai_next)
2821				error("bind: %.100s", strerror(errno));
2822			else
2823				verbose("bind: %.100s", strerror(errno));
2824
2825			close(sock);
2826			continue;
2827		}
2828		/* Start listening for connections on the socket. */
2829		if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2830			error("listen: %.100s", strerror(errno));
2831			close(sock);
2832			continue;
2833		}
2834
2835		/*
2836		 * listen_port == 0 requests a dynamically allocated port -
2837		 * record what we got.
2838		 */
2839		if (type == SSH_CHANNEL_RPORT_LISTENER && listen_port == 0 &&
2840		    allocated_listen_port != NULL &&
2841		    *allocated_listen_port == 0) {
2842			*allocated_listen_port = get_sock_port(sock, 1);
2843			debug("Allocated listen port %d",
2844			    *allocated_listen_port);
2845		}
2846
2847		/* Allocate a channel number for the socket. */
2848		c = channel_new("port listener", type, sock, sock, -1,
2849		    CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2850		    0, "port listener", 1);
2851		c->path = xstrdup(host);
2852		c->host_port = port_to_connect;
2853		c->listening_addr = addr == NULL ? NULL : xstrdup(addr);
2854		if (listen_port == 0 && allocated_listen_port != NULL &&
2855		    !(datafellows & SSH_BUG_DYNAMIC_RPORT))
2856			c->listening_port = *allocated_listen_port;
2857		else
2858			c->listening_port = listen_port;
2859		success = 1;
2860	}
2861	if (success == 0)
2862		error("channel_setup_fwd_listener: cannot listen to port: %d",
2863		    listen_port);
2864	freeaddrinfo(aitop);
2865	return success;
2866}
2867
2868int
2869channel_cancel_rport_listener(const char *host, u_short port)
2870{
2871	u_int i;
2872	int found = 0;
2873
2874	for (i = 0; i < channels_alloc; i++) {
2875		Channel *c = channels[i];
2876		if (c == NULL || c->type != SSH_CHANNEL_RPORT_LISTENER)
2877			continue;
2878		if (strcmp(c->path, host) == 0 && c->listening_port == port) {
2879			debug2("%s: close channel %d", __func__, i);
2880			channel_free(c);
2881			found = 1;
2882		}
2883	}
2884
2885	return (found);
2886}
2887
2888int
2889channel_cancel_lport_listener(const char *lhost, u_short lport,
2890    int cport, int gateway_ports)
2891{
2892	u_int i;
2893	int found = 0;
2894	const char *addr = channel_fwd_bind_addr(lhost, NULL, 1, gateway_ports);
2895
2896	for (i = 0; i < channels_alloc; i++) {
2897		Channel *c = channels[i];
2898		if (c == NULL || c->type != SSH_CHANNEL_PORT_LISTENER)
2899			continue;
2900		if (c->listening_port != lport)
2901			continue;
2902		if (cport == CHANNEL_CANCEL_PORT_STATIC) {
2903			/* skip dynamic forwardings */
2904			if (c->host_port == 0)
2905				continue;
2906		} else {
2907			if (c->host_port != cport)
2908				continue;
2909		}
2910		if ((c->listening_addr == NULL && addr != NULL) ||
2911		    (c->listening_addr != NULL && addr == NULL))
2912			continue;
2913		if (addr == NULL || strcmp(c->listening_addr, addr) == 0) {
2914			debug2("%s: close channel %d", __func__, i);
2915			channel_free(c);
2916			found = 1;
2917		}
2918	}
2919
2920	return (found);
2921}
2922
2923/* protocol local port fwd, used by ssh (and sshd in v1) */
2924int
2925channel_setup_local_fwd_listener(const char *listen_host, u_short listen_port,
2926    const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2927{
2928	return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER,
2929	    listen_host, listen_port, NULL, host_to_connect, port_to_connect,
2930	    gateway_ports);
2931}
2932
2933/* protocol v2 remote port fwd, used by sshd */
2934int
2935channel_setup_remote_fwd_listener(const char *listen_address,
2936    u_short listen_port, int *allocated_listen_port, int gateway_ports)
2937{
2938	return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER,
2939	    listen_address, listen_port, allocated_listen_port,
2940	    NULL, 0, gateway_ports);
2941}
2942
2943/*
2944 * Translate the requested rfwd listen host to something usable for
2945 * this server.
2946 */
2947static const char *
2948channel_rfwd_bind_host(const char *listen_host)
2949{
2950	if (listen_host == NULL) {
2951		if (datafellows & SSH_BUG_RFWD_ADDR)
2952			return "127.0.0.1";
2953		else
2954			return "localhost";
2955	} else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0) {
2956		if (datafellows & SSH_BUG_RFWD_ADDR)
2957			return "0.0.0.0";
2958		else
2959			return "";
2960	} else
2961		return listen_host;
2962}
2963
2964/*
2965 * Initiate forwarding of connections to port "port" on remote host through
2966 * the secure channel to host:port from local side.
2967 * Returns handle (index) for updating the dynamic listen port with
2968 * channel_update_permitted_opens().
2969 */
2970int
2971channel_request_remote_forwarding(const char *listen_host, u_short listen_port,
2972    const char *host_to_connect, u_short port_to_connect)
2973{
2974	int type, success = 0, idx = -1;
2975
2976	/* Send the forward request to the remote side. */
2977	if (compat20) {
2978		packet_start(SSH2_MSG_GLOBAL_REQUEST);
2979		packet_put_cstring("tcpip-forward");
2980		packet_put_char(1);		/* boolean: want reply */
2981		packet_put_cstring(channel_rfwd_bind_host(listen_host));
2982		packet_put_int(listen_port);
2983		packet_send();
2984		packet_write_wait();
2985		/* Assume that server accepts the request */
2986		success = 1;
2987	} else {
2988		packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2989		packet_put_int(listen_port);
2990		packet_put_cstring(host_to_connect);
2991		packet_put_int(port_to_connect);
2992		packet_send();
2993		packet_write_wait();
2994
2995		/* Wait for response from the remote side. */
2996		type = packet_read();
2997		switch (type) {
2998		case SSH_SMSG_SUCCESS:
2999			success = 1;
3000			break;
3001		case SSH_SMSG_FAILURE:
3002			break;
3003		default:
3004			/* Unknown packet */
3005			packet_disconnect("Protocol error for port forward request:"
3006			    "received packet type %d.", type);
3007		}
3008	}
3009	if (success) {
3010		/* Record that connection to this host/port is permitted. */
3011		permitted_opens = xrealloc(permitted_opens,
3012		    num_permitted_opens + 1, sizeof(*permitted_opens));
3013		idx = num_permitted_opens++;
3014		permitted_opens[idx].host_to_connect = xstrdup(host_to_connect);
3015		permitted_opens[idx].port_to_connect = port_to_connect;
3016		permitted_opens[idx].listen_port = listen_port;
3017	}
3018	return (idx);
3019}
3020
3021/*
3022 * Request cancellation of remote forwarding of connection host:port from
3023 * local side.
3024 */
3025int
3026channel_request_rforward_cancel(const char *host, u_short port)
3027{
3028	int i;
3029
3030	if (!compat20)
3031		return -1;
3032
3033	for (i = 0; i < num_permitted_opens; i++) {
3034		if (permitted_opens[i].host_to_connect != NULL &&
3035		    permitted_opens[i].listen_port == port)
3036			break;
3037	}
3038	if (i >= num_permitted_opens) {
3039		debug("%s: requested forward not found", __func__);
3040		return -1;
3041	}
3042	packet_start(SSH2_MSG_GLOBAL_REQUEST);
3043	packet_put_cstring("cancel-tcpip-forward");
3044	packet_put_char(0);
3045	packet_put_cstring(channel_rfwd_bind_host(host));
3046	packet_put_int(port);
3047	packet_send();
3048
3049	permitted_opens[i].listen_port = 0;
3050	permitted_opens[i].port_to_connect = 0;
3051	xfree(permitted_opens[i].host_to_connect);
3052	permitted_opens[i].host_to_connect = NULL;
3053
3054	return 0;
3055}
3056
3057/*
3058 * This is called after receiving CHANNEL_FORWARDING_REQUEST.  This initates
3059 * listening for the port, and sends back a success reply (or disconnect
3060 * message if there was an error).
3061 */
3062int
3063channel_input_port_forward_request(int is_root, int gateway_ports)
3064{
3065	u_short port, host_port;
3066	int success = 0;
3067	char *hostname;
3068
3069	/* Get arguments from the packet. */
3070	port = packet_get_int();
3071	hostname = packet_get_string(NULL);
3072	host_port = packet_get_int();
3073
3074#ifndef HAVE_CYGWIN
3075	/*
3076	 * Check that an unprivileged user is not trying to forward a
3077	 * privileged port.
3078	 */
3079	if (port < IPPORT_RESERVED && !is_root)
3080		packet_disconnect(
3081		    "Requested forwarding of port %d but user is not root.",
3082		    port);
3083	if (host_port == 0)
3084		packet_disconnect("Dynamic forwarding denied.");
3085#endif
3086
3087	/* Initiate forwarding */
3088	success = channel_setup_local_fwd_listener(NULL, port, hostname,
3089	    host_port, gateway_ports);
3090
3091	/* Free the argument string. */
3092	xfree(hostname);
3093
3094	return (success ? 0 : -1);
3095}
3096
3097/*
3098 * Permits opening to any host/port if permitted_opens[] is empty.  This is
3099 * usually called by the server, because the user could connect to any port
3100 * anyway, and the server has no way to know but to trust the client anyway.
3101 */
3102void
3103channel_permit_all_opens(void)
3104{
3105	if (num_permitted_opens == 0)
3106		all_opens_permitted = 1;
3107}
3108
3109void
3110channel_add_permitted_opens(char *host, int port)
3111{
3112	debug("allow port forwarding to host %s port %d", host, port);
3113
3114	permitted_opens = xrealloc(permitted_opens,
3115	    num_permitted_opens + 1, sizeof(*permitted_opens));
3116	permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
3117	permitted_opens[num_permitted_opens].port_to_connect = port;
3118	num_permitted_opens++;
3119
3120	all_opens_permitted = 0;
3121}
3122
3123/*
3124 * Update the listen port for a dynamic remote forward, after
3125 * the actual 'newport' has been allocated. If 'newport' < 0 is
3126 * passed then they entry will be invalidated.
3127 */
3128void
3129channel_update_permitted_opens(int idx, int newport)
3130{
3131	if (idx < 0 || idx >= num_permitted_opens) {
3132		debug("channel_update_permitted_opens: index out of range:"
3133		    " %d num_permitted_opens %d", idx, num_permitted_opens);
3134		return;
3135	}
3136	debug("%s allowed port %d for forwarding to host %s port %d",
3137	    newport > 0 ? "Updating" : "Removing",
3138	    newport,
3139	    permitted_opens[idx].host_to_connect,
3140	    permitted_opens[idx].port_to_connect);
3141	if (newport >= 0)  {
3142		permitted_opens[idx].listen_port =
3143		    (datafellows & SSH_BUG_DYNAMIC_RPORT) ? 0 : newport;
3144	} else {
3145		permitted_opens[idx].listen_port = 0;
3146		permitted_opens[idx].port_to_connect = 0;
3147		xfree(permitted_opens[idx].host_to_connect);
3148		permitted_opens[idx].host_to_connect = NULL;
3149	}
3150}
3151
3152int
3153channel_add_adm_permitted_opens(char *host, int port)
3154{
3155	debug("config allows port forwarding to host %s port %d", host, port);
3156
3157	permitted_adm_opens = xrealloc(permitted_adm_opens,
3158	    num_adm_permitted_opens + 1, sizeof(*permitted_adm_opens));
3159	permitted_adm_opens[num_adm_permitted_opens].host_to_connect
3160	     = xstrdup(host);
3161	permitted_adm_opens[num_adm_permitted_opens].port_to_connect = port;
3162	return ++num_adm_permitted_opens;
3163}
3164
3165void
3166channel_disable_adm_local_opens(void)
3167{
3168	channel_clear_adm_permitted_opens();
3169	permitted_adm_opens = xmalloc(sizeof(*permitted_adm_opens));
3170	permitted_adm_opens[num_adm_permitted_opens].host_to_connect = NULL;
3171	num_adm_permitted_opens = 1;
3172}
3173
3174void
3175channel_clear_permitted_opens(void)
3176{
3177	int i;
3178
3179	for (i = 0; i < num_permitted_opens; i++)
3180		if (permitted_opens[i].host_to_connect != NULL)
3181			xfree(permitted_opens[i].host_to_connect);
3182	if (num_permitted_opens > 0) {
3183		xfree(permitted_opens);
3184		permitted_opens = NULL;
3185	}
3186	num_permitted_opens = 0;
3187}
3188
3189void
3190channel_clear_adm_permitted_opens(void)
3191{
3192	int i;
3193
3194	for (i = 0; i < num_adm_permitted_opens; i++)
3195		if (permitted_adm_opens[i].host_to_connect != NULL)
3196			xfree(permitted_adm_opens[i].host_to_connect);
3197	if (num_adm_permitted_opens > 0) {
3198		xfree(permitted_adm_opens);
3199		permitted_adm_opens = NULL;
3200	}
3201	num_adm_permitted_opens = 0;
3202}
3203
3204void
3205channel_print_adm_permitted_opens(void)
3206{
3207	int i;
3208
3209	printf("permitopen");
3210	if (num_adm_permitted_opens == 0) {
3211		printf(" any\n");
3212		return;
3213	}
3214	for (i = 0; i < num_adm_permitted_opens; i++)
3215		if (permitted_adm_opens[i].host_to_connect == NULL)
3216			printf(" none");
3217		else
3218			printf(" %s:%d", permitted_adm_opens[i].host_to_connect,
3219			    permitted_adm_opens[i].port_to_connect);
3220	printf("\n");
3221}
3222
3223/* returns port number, FWD_PERMIT_ANY_PORT or -1 on error */
3224int
3225permitopen_port(const char *p)
3226{
3227	int port;
3228
3229	if (strcmp(p, "*") == 0)
3230		return FWD_PERMIT_ANY_PORT;
3231	if ((port = a2port(p)) > 0)
3232		return port;
3233	return -1;
3234}
3235
3236static int
3237port_match(u_short allowedport, u_short requestedport)
3238{
3239	if (allowedport == FWD_PERMIT_ANY_PORT ||
3240	    allowedport == requestedport)
3241		return 1;
3242	return 0;
3243}
3244
3245/* Try to start non-blocking connect to next host in cctx list */
3246static int
3247connect_next(struct channel_connect *cctx)
3248{
3249	int sock, saved_errno;
3250	char ntop[NI_MAXHOST], strport[NI_MAXSERV];
3251
3252	for (; cctx->ai; cctx->ai = cctx->ai->ai_next) {
3253		if (cctx->ai->ai_family != AF_INET &&
3254		    cctx->ai->ai_family != AF_INET6)
3255			continue;
3256		if (getnameinfo(cctx->ai->ai_addr, cctx->ai->ai_addrlen,
3257		    ntop, sizeof(ntop), strport, sizeof(strport),
3258		    NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
3259			error("connect_next: getnameinfo failed");
3260			continue;
3261		}
3262		if ((sock = socket(cctx->ai->ai_family, cctx->ai->ai_socktype,
3263		    cctx->ai->ai_protocol)) == -1) {
3264			if (cctx->ai->ai_next == NULL)
3265				error("socket: %.100s", strerror(errno));
3266			else
3267				verbose("socket: %.100s", strerror(errno));
3268			continue;
3269		}
3270		if (set_nonblock(sock) == -1)
3271			fatal("%s: set_nonblock(%d)", __func__, sock);
3272		if (connect(sock, cctx->ai->ai_addr,
3273		    cctx->ai->ai_addrlen) == -1 && errno != EINPROGRESS) {
3274			debug("connect_next: host %.100s ([%.100s]:%s): "
3275			    "%.100s", cctx->host, ntop, strport,
3276			    strerror(errno));
3277			saved_errno = errno;
3278			close(sock);
3279			errno = saved_errno;
3280			continue;	/* fail -- try next */
3281		}
3282		debug("connect_next: host %.100s ([%.100s]:%s) "
3283		    "in progress, fd=%d", cctx->host, ntop, strport, sock);
3284		cctx->ai = cctx->ai->ai_next;
3285		set_nodelay(sock);
3286		return sock;
3287	}
3288	return -1;
3289}
3290
3291static void
3292channel_connect_ctx_free(struct channel_connect *cctx)
3293{
3294	xfree(cctx->host);
3295	if (cctx->aitop)
3296		freeaddrinfo(cctx->aitop);
3297	bzero(cctx, sizeof(*cctx));
3298	cctx->host = NULL;
3299	cctx->ai = cctx->aitop = NULL;
3300}
3301
3302/* Return CONNECTING channel to remote host, port */
3303static Channel *
3304connect_to(const char *host, u_short port, char *ctype, char *rname)
3305{
3306	struct addrinfo hints;
3307	int gaierr;
3308	int sock = -1;
3309	char strport[NI_MAXSERV];
3310	struct channel_connect cctx;
3311	Channel *c;
3312
3313	memset(&cctx, 0, sizeof(cctx));
3314	memset(&hints, 0, sizeof(hints));
3315	hints.ai_family = IPv4or6;
3316	hints.ai_socktype = SOCK_STREAM;
3317	snprintf(strport, sizeof strport, "%d", port);
3318	if ((gaierr = getaddrinfo(host, strport, &hints, &cctx.aitop)) != 0) {
3319		error("connect_to %.100s: unknown host (%s)", host,
3320		    ssh_gai_strerror(gaierr));
3321		return NULL;
3322	}
3323
3324	cctx.host = xstrdup(host);
3325	cctx.port = port;
3326	cctx.ai = cctx.aitop;
3327
3328	if ((sock = connect_next(&cctx)) == -1) {
3329		error("connect to %.100s port %d failed: %s",
3330		    host, port, strerror(errno));
3331		channel_connect_ctx_free(&cctx);
3332		return NULL;
3333	}
3334	c = channel_new(ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1,
3335	    CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1);
3336	c->connect_ctx = cctx;
3337	return c;
3338}
3339
3340Channel *
3341channel_connect_by_listen_address(u_short listen_port, char *ctype, char *rname)
3342{
3343	int i;
3344
3345	for (i = 0; i < num_permitted_opens; i++) {
3346		if (permitted_opens[i].host_to_connect != NULL &&
3347		    port_match(permitted_opens[i].listen_port, listen_port)) {
3348			return connect_to(
3349			    permitted_opens[i].host_to_connect,
3350			    permitted_opens[i].port_to_connect, ctype, rname);
3351		}
3352	}
3353	error("WARNING: Server requests forwarding for unknown listen_port %d",
3354	    listen_port);
3355	return NULL;
3356}
3357
3358/* Check if connecting to that port is permitted and connect. */
3359Channel *
3360channel_connect_to(const char *host, u_short port, char *ctype, char *rname)
3361{
3362	int i, permit, permit_adm = 1;
3363
3364	permit = all_opens_permitted;
3365	if (!permit) {
3366		for (i = 0; i < num_permitted_opens; i++)
3367			if (permitted_opens[i].host_to_connect != NULL &&
3368			    port_match(permitted_opens[i].port_to_connect, port) &&
3369			    strcmp(permitted_opens[i].host_to_connect, host) == 0)
3370				permit = 1;
3371	}
3372
3373	if (num_adm_permitted_opens > 0) {
3374		permit_adm = 0;
3375		for (i = 0; i < num_adm_permitted_opens; i++)
3376			if (permitted_adm_opens[i].host_to_connect != NULL &&
3377			    port_match(permitted_adm_opens[i].port_to_connect, port) &&
3378			    strcmp(permitted_adm_opens[i].host_to_connect, host)
3379			    == 0)
3380				permit_adm = 1;
3381	}
3382
3383	if (!permit || !permit_adm) {
3384		logit("Received request to connect to host %.100s port %d, "
3385		    "but the request was denied.", host, port);
3386		return NULL;
3387	}
3388	return connect_to(host, port, ctype, rname);
3389}
3390
3391void
3392channel_send_window_changes(void)
3393{
3394	u_int i;
3395	struct winsize ws;
3396
3397	for (i = 0; i < channels_alloc; i++) {
3398		if (channels[i] == NULL || !channels[i]->client_tty ||
3399		    channels[i]->type != SSH_CHANNEL_OPEN)
3400			continue;
3401		if (ioctl(channels[i]->rfd, TIOCGWINSZ, &ws) < 0)
3402			continue;
3403		channel_request_start(i, "window-change", 0);
3404		packet_put_int((u_int)ws.ws_col);
3405		packet_put_int((u_int)ws.ws_row);
3406		packet_put_int((u_int)ws.ws_xpixel);
3407		packet_put_int((u_int)ws.ws_ypixel);
3408		packet_send();
3409	}
3410}
3411
3412/* -- X11 forwarding */
3413
3414/*
3415 * Creates an internet domain socket for listening for X11 connections.
3416 * Returns 0 and a suitable display number for the DISPLAY variable
3417 * stored in display_numberp , or -1 if an error occurs.
3418 */
3419int
3420x11_create_display_inet(int x11_display_offset, int x11_use_localhost,
3421    int single_connection, u_int *display_numberp, int **chanids)
3422{
3423	Channel *nc = NULL;
3424	int display_number, sock;
3425	u_short port;
3426	struct addrinfo hints, *ai, *aitop;
3427	char strport[NI_MAXSERV];
3428	int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
3429
3430	if (chanids == NULL)
3431		return -1;
3432
3433	for (display_number = x11_display_offset;
3434	    display_number < MAX_DISPLAYS;
3435	    display_number++) {
3436		port = 6000 + display_number;
3437		memset(&hints, 0, sizeof(hints));
3438		hints.ai_family = IPv4or6;
3439		hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE;
3440		hints.ai_socktype = SOCK_STREAM;
3441		snprintf(strport, sizeof strport, "%d", port);
3442		if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
3443			error("getaddrinfo: %.100s", ssh_gai_strerror(gaierr));
3444			return -1;
3445		}
3446		for (ai = aitop; ai; ai = ai->ai_next) {
3447			if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
3448				continue;
3449			sock = socket(ai->ai_family, ai->ai_socktype,
3450			    ai->ai_protocol);
3451			if (sock < 0) {
3452				if ((errno != EINVAL) && (errno != EAFNOSUPPORT)
3453#ifdef EPFNOSUPPORT
3454				    && (errno != EPFNOSUPPORT)
3455#endif
3456				    ) {
3457					error("socket: %.100s", strerror(errno));
3458					freeaddrinfo(aitop);
3459					return -1;
3460				} else {
3461					debug("x11_create_display_inet: Socket family %d not supported",
3462						 ai->ai_family);
3463					continue;
3464				}
3465			}
3466			if (ai->ai_family == AF_INET6)
3467				sock_set_v6only(sock);
3468			if (x11_use_localhost)
3469				channel_set_reuseaddr(sock);
3470			if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
3471				debug2("bind port %d: %.100s", port, strerror(errno));
3472				close(sock);
3473
3474				for (n = 0; n < num_socks; n++) {
3475					close(socks[n]);
3476				}
3477				num_socks = 0;
3478				break;
3479			}
3480			socks[num_socks++] = sock;
3481			if (num_socks == NUM_SOCKS)
3482				break;
3483		}
3484		freeaddrinfo(aitop);
3485		if (num_socks > 0)
3486			break;
3487	}
3488	if (display_number >= MAX_DISPLAYS) {
3489		error("Failed to allocate internet-domain X11 display socket.");
3490		return -1;
3491	}
3492	/* Start listening for connections on the socket. */
3493	for (n = 0; n < num_socks; n++) {
3494		sock = socks[n];
3495		if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
3496			error("listen: %.100s", strerror(errno));
3497			close(sock);
3498			return -1;
3499		}
3500	}
3501
3502	/* Allocate a channel for each socket. */
3503	*chanids = xcalloc(num_socks + 1, sizeof(**chanids));
3504	for (n = 0; n < num_socks; n++) {
3505		sock = socks[n];
3506		nc = channel_new("x11 listener",
3507		    SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
3508		    CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
3509		    0, "X11 inet listener", 1);
3510		nc->single_connection = single_connection;
3511		(*chanids)[n] = nc->self;
3512	}
3513	(*chanids)[n] = -1;
3514
3515	/* Return the display number for the DISPLAY environment variable. */
3516	*display_numberp = display_number;
3517	return (0);
3518}
3519
3520static int
3521connect_local_xsocket_path(const char *pathname)
3522{
3523	int sock;
3524	struct sockaddr_un addr;
3525
3526	sock = socket(AF_UNIX, SOCK_STREAM, 0);
3527	if (sock < 0)
3528		error("socket: %.100s", strerror(errno));
3529	memset(&addr, 0, sizeof(addr));
3530	addr.sun_family = AF_UNIX;
3531	strlcpy(addr.sun_path, pathname, sizeof addr.sun_path);
3532	if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0)
3533		return sock;
3534	close(sock);
3535	error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
3536	return -1;
3537}
3538
3539static int
3540connect_local_xsocket(u_int dnr)
3541{
3542	char buf[1024];
3543	snprintf(buf, sizeof buf, _PATH_UNIX_X, dnr);
3544	return connect_local_xsocket_path(buf);
3545}
3546
3547int
3548x11_connect_display(void)
3549{
3550	u_int display_number;
3551	const char *display;
3552	char buf[1024], *cp;
3553	struct addrinfo hints, *ai, *aitop;
3554	char strport[NI_MAXSERV];
3555	int gaierr, sock = 0;
3556
3557	/* Try to open a socket for the local X server. */
3558	display = getenv("DISPLAY");
3559	if (!display) {
3560		error("DISPLAY not set.");
3561		return -1;
3562	}
3563	/*
3564	 * Now we decode the value of the DISPLAY variable and make a
3565	 * connection to the real X server.
3566	 */
3567
3568#ifdef __APPLE__
3569	/* Check if the display is a path to a socket (as set by launchd). */
3570	{
3571		char path[PATH_MAX];
3572		struct stat sbuf;
3573		int is_path_to_socket = 0;
3574
3575		strlcpy(path, display, sizeof(path));
3576		if (0 == stat(path, &sbuf)) {
3577			is_path_to_socket = 1;
3578		} else {
3579			char *dot = strrchr(path, '.');
3580			if (dot) {
3581				*dot = '\0';
3582				/* screen = atoi(dot + 1); */
3583				if (0 == stat(path, &sbuf)) {
3584					is_path_to_socket=1;
3585				}
3586			}
3587		}
3588
3589		if (is_path_to_socket) {
3590			sock = connect_local_xsocket_path(path);
3591			if (sock < 0)
3592				return -1;
3593
3594			/* OK, we now have a connection to the display. */
3595			return sock;
3596		}
3597	}
3598#endif
3599	/*
3600	 * Check if it is a unix domain socket.  Unix domain displays are in
3601	 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
3602	 */
3603	if (strncmp(display, "unix:", 5) == 0 ||
3604	    display[0] == ':') {
3605		/* Connect to the unix domain socket. */
3606		if (sscanf(strrchr(display, ':') + 1, "%u", &display_number) != 1) {
3607			error("Could not parse display number from DISPLAY: %.100s",
3608			    display);
3609			return -1;
3610		}
3611		/* Create a socket. */
3612		sock = connect_local_xsocket(display_number);
3613		if (sock < 0)
3614			return -1;
3615
3616		/* OK, we now have a connection to the display. */
3617		return sock;
3618	}
3619	/*
3620	 * Connect to an inet socket.  The DISPLAY value is supposedly
3621	 * hostname:d[.s], where hostname may also be numeric IP address.
3622	 */
3623	strlcpy(buf, display, sizeof(buf));
3624	cp = strchr(buf, ':');
3625	if (!cp) {
3626		error("Could not find ':' in DISPLAY: %.100s", display);
3627		return -1;
3628	}
3629	*cp = 0;
3630	/* buf now contains the host name.  But first we parse the display number. */
3631	if (sscanf(cp + 1, "%u", &display_number) != 1) {
3632		error("Could not parse display number from DISPLAY: %.100s",
3633		    display);
3634		return -1;
3635	}
3636
3637	/* Look up the host address */
3638	memset(&hints, 0, sizeof(hints));
3639	hints.ai_family = IPv4or6;
3640	hints.ai_socktype = SOCK_STREAM;
3641	snprintf(strport, sizeof strport, "%u", 6000 + display_number);
3642	if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
3643		error("%.100s: unknown host. (%s)", buf,
3644		ssh_gai_strerror(gaierr));
3645		return -1;
3646	}
3647	for (ai = aitop; ai; ai = ai->ai_next) {
3648		/* Create a socket. */
3649		sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
3650		if (sock < 0) {
3651			debug2("socket: %.100s", strerror(errno));
3652			continue;
3653		}
3654		/* Connect it to the display. */
3655		if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
3656			debug2("connect %.100s port %u: %.100s", buf,
3657			    6000 + display_number, strerror(errno));
3658			close(sock);
3659			continue;
3660		}
3661		/* Success */
3662		break;
3663	}
3664	freeaddrinfo(aitop);
3665	if (!ai) {
3666		error("connect %.100s port %u: %.100s", buf, 6000 + display_number,
3667		    strerror(errno));
3668		return -1;
3669	}
3670	set_nodelay(sock);
3671	return sock;
3672}
3673
3674/*
3675 * This is called when SSH_SMSG_X11_OPEN is received.  The packet contains
3676 * the remote channel number.  We should do whatever we want, and respond
3677 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
3678 */
3679
3680/* ARGSUSED */
3681void
3682x11_input_open(int type, u_int32_t seq, void *ctxt)
3683{
3684	Channel *c = NULL;
3685	int remote_id, sock = 0;
3686	char *remote_host;
3687
3688	debug("Received X11 open request.");
3689
3690	remote_id = packet_get_int();
3691
3692	if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
3693		remote_host = packet_get_string(NULL);
3694	} else {
3695		remote_host = xstrdup("unknown (remote did not supply name)");
3696	}
3697	packet_check_eom();
3698
3699	/* Obtain a connection to the real X display. */
3700	sock = x11_connect_display();
3701	if (sock != -1) {
3702		/* Allocate a channel for this connection. */
3703		c = channel_new("connected x11 socket",
3704		    SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
3705		    remote_host, 1);
3706		c->remote_id = remote_id;
3707		c->force_drain = 1;
3708	}
3709	xfree(remote_host);
3710	if (c == NULL) {
3711		/* Send refusal to the remote host. */
3712		packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3713		packet_put_int(remote_id);
3714	} else {
3715		/* Send a confirmation to the remote host. */
3716		packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
3717		packet_put_int(remote_id);
3718		packet_put_int(c->self);
3719	}
3720	packet_send();
3721}
3722
3723/* dummy protocol handler that denies SSH-1 requests (agent/x11) */
3724/* ARGSUSED */
3725void
3726deny_input_open(int type, u_int32_t seq, void *ctxt)
3727{
3728	int rchan = packet_get_int();
3729
3730	switch (type) {
3731	case SSH_SMSG_AGENT_OPEN:
3732		error("Warning: ssh server tried agent forwarding.");
3733		break;
3734	case SSH_SMSG_X11_OPEN:
3735		error("Warning: ssh server tried X11 forwarding.");
3736		break;
3737	default:
3738		error("deny_input_open: type %d", type);
3739		break;
3740	}
3741	error("Warning: this is probably a break-in attempt by a malicious server.");
3742	packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3743	packet_put_int(rchan);
3744	packet_send();
3745}
3746
3747/*
3748 * Requests forwarding of X11 connections, generates fake authentication
3749 * data, and enables authentication spoofing.
3750 * This should be called in the client only.
3751 */
3752void
3753x11_request_forwarding_with_spoofing(int client_session_id, const char *disp,
3754    const char *proto, const char *data, int want_reply)
3755{
3756	u_int data_len = (u_int) strlen(data) / 2;
3757	u_int i, value;
3758	char *new_data;
3759	int screen_number;
3760	const char *cp;
3761	u_int32_t rnd = 0;
3762
3763	if (x11_saved_display == NULL)
3764		x11_saved_display = xstrdup(disp);
3765	else if (strcmp(disp, x11_saved_display) != 0) {
3766		error("x11_request_forwarding_with_spoofing: different "
3767		    "$DISPLAY already forwarded");
3768		return;
3769	}
3770
3771	cp = strchr(disp, ':');
3772	if (cp)
3773		cp = strchr(cp, '.');
3774	if (cp)
3775		screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL);
3776	else
3777		screen_number = 0;
3778
3779	if (x11_saved_proto == NULL) {
3780		/* Save protocol name. */
3781		x11_saved_proto = xstrdup(proto);
3782		/*
3783		 * Extract real authentication data and generate fake data
3784		 * of the same length.
3785		 */
3786		x11_saved_data = xmalloc(data_len);
3787		x11_fake_data = xmalloc(data_len);
3788		for (i = 0; i < data_len; i++) {
3789			if (sscanf(data + 2 * i, "%2x", &value) != 1)
3790				fatal("x11_request_forwarding: bad "
3791				    "authentication data: %.100s", data);
3792			if (i % 4 == 0)
3793				rnd = arc4random();
3794			x11_saved_data[i] = value;
3795			x11_fake_data[i] = rnd & 0xff;
3796			rnd >>= 8;
3797		}
3798		x11_saved_data_len = data_len;
3799		x11_fake_data_len = data_len;
3800	}
3801
3802	/* Convert the fake data into hex. */
3803	new_data = tohex(x11_fake_data, data_len);
3804
3805	/* Send the request packet. */
3806	if (compat20) {
3807		channel_request_start(client_session_id, "x11-req", want_reply);
3808		packet_put_char(0);	/* XXX bool single connection */
3809	} else {
3810		packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
3811	}
3812	packet_put_cstring(proto);
3813	packet_put_cstring(new_data);
3814	packet_put_int(screen_number);
3815	packet_send();
3816	packet_write_wait();
3817	xfree(new_data);
3818}
3819
3820
3821/* -- agent forwarding */
3822
3823/* Sends a message to the server to request authentication fd forwarding. */
3824
3825void
3826auth_request_forwarding(void)
3827{
3828	packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
3829	packet_send();
3830	packet_write_wait();
3831}
3832