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[netbsd-mini2440.git] / crypto / external / bsd / openssh / dist / channels.c
blobc8954f4707a60d364a40f0029224bc7a2bdd746e
1 /* $NetBSD: channels.c,v 1.1.1.2 2009/12/27 01:06:52 christos Exp $ */
2 /* $OpenBSD: channels.c,v 1.296 2009/05/25 06:48:00 andreas Exp $ */
3 /*
4 * Author: Tatu Ylonen <ylo@cs.hut.fi>
5 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
6 * All rights reserved
7 * This file contains functions for generic socket connection forwarding.
8 * There is also code for initiating connection forwarding for X11 connections,
9 * arbitrary tcp/ip connections, and the authentication agent connection.
10 *
11 * As far as I am concerned, the code I have written for this software
12 * can be used freely for any purpose. Any derived versions of this
13 * software must be clearly marked as such, and if the derived work is
14 * incompatible with the protocol description in the RFC file, it must be
15 * called by a name other than "ssh" or "Secure Shell".
16 *
17 * SSH2 support added by Markus Friedl.
18 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved.
19 * Copyright (c) 1999 Dug Song. All rights reserved.
20 * Copyright (c) 1999 Theo de Raadt. All rights reserved.
21 *
22 * Redistribution and use in source and binary forms, with or without
23 * modification, are permitted provided that the following conditions
24 * are met:
25 * 1. Redistributions of source code must retain the above copyright
26 * notice, this list of conditions and the following disclaimer.
27 * 2. Redistributions in binary form must reproduce the above copyright
28 * notice, this list of conditions and the following disclaimer in the
29 * documentation and/or other materials provided with the distribution.
30 *
31 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
32 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
33 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
34 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
35 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
36 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
37 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
38 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
39 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
40 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
41 */
42
43 #include "includes.h"
44 __RCSID("$NetBSD: channels.c,v 1.2 2009/06/07 22:38:46 christos Exp $");
45 #include <sys/param.h>
46 #include <sys/types.h>
47 #include <sys/ioctl.h>
48 #include <sys/un.h>
49 #include <sys/socket.h>
50 #include <sys/time.h>
51 #include <sys/queue.h>
52
53 #include <netinet/in.h>
54 #include <arpa/inet.h>
55
56 #include <errno.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 "xmalloc.h"
66 #include "ssh.h"
67 #include "ssh1.h"
68 #include "ssh2.h"
69 #include "packet.h"
70 #include "log.h"
71 #include "misc.h"
72 #include "buffer.h"
73 #include "channels.h"
74 #include "compat.h"
75 #include "canohost.h"
76 #include "key.h"
77 #include "authfd.h"
78 #include "pathnames.h"
79
80
81 static int hpn_disabled = 0;
82 static int hpn_buffer_size = 2 * 1024 * 1024;
83
84 /* -- channel core */
85
86 /*
87 * Pointer to an array containing all allocated channels. The array is
88 * dynamically extended as needed.
89 */
90 static Channel **channels = NULL;
91
92 /*
93 * Size of the channel array. All slots of the array must always be
94 * initialized (at least the type field); unused slots set to NULL
95 */
96 static u_int channels_alloc = 0;
97
98 /*
99 * Maximum file descriptor value used in any of the channels. This is
100 * updated in channel_new.
101 */
102 static int channel_max_fd = 0;
103
104
105 /* -- tcp forwarding */
106
107 /*
108 * Data structure for storing which hosts are permitted for forward requests.
109 * The local sides of any remote forwards are stored in this array to prevent
110 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local
111 * network (which might be behind a firewall).
112 */
113 typedef struct {
114 char *host_to_connect; /* Connect to 'host'. */
115 u_short port_to_connect; /* Connect to 'port'. */
116 u_short listen_port; /* Remote side should listen port number. */
117 } ForwardPermission;
118
119 /* List of all permitted host/port pairs to connect by the user. */
120 static ForwardPermission permitted_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
121
122 /* List of all permitted host/port pairs to connect by the admin. */
123 static ForwardPermission permitted_adm_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
124
125 /* Number of permitted host/port pairs in the array permitted by the user. */
126 static int num_permitted_opens = 0;
127
128 /* Number of permitted host/port pair in the array permitted by the admin. */
129 static int num_adm_permitted_opens = 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 */
136 static 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. */
145 static char *x11_saved_display = NULL;
146
147 /* Saved X11 authentication protocol name. */
148 static char *x11_saved_proto = NULL;
149
150 /* Saved X11 authentication data. This is the real data. */
151 static char *x11_saved_data = NULL;
152 static 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 */
158 static u_char *x11_fake_data = NULL;
159 static 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 */
167 static int IPv4or6 = AF_UNSPEC;
168
169 /* helper */
170 static void port_open_helper(Channel *c, char *rtype);
171
172 /* non-blocking connect helpers */
173 static int connect_next(struct channel_connect *);
174 static void channel_connect_ctx_free(struct channel_connect *);
175
176 /* -- channel core */
177
178 Channel *
179 channel_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 */
199 Channel *
200 channel_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 */
226 static void
227 channel_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 /* XXX set close-on-exec -markus */
236
237 c->rfd = rfd;
238 c->wfd = wfd;
239 c->sock = (rfd == wfd) ? rfd : -1;
240 c->ctl_fd = -1; /* XXX: set elsewhere */
241 c->efd = efd;
242 c->extended_usage = extusage;
243
244 if ((c->isatty = is_tty) != 0)
245 debug2("channel %d: rfd %d isatty", c->self, c->rfd);
246
247 /* enable nonblocking mode */
248 if (nonblock) {
249 if (rfd != -1)
250 set_nonblock(rfd);
251 if (wfd != -1)
252 set_nonblock(wfd);
253 if (efd != -1)
254 set_nonblock(efd);
255 }
256 }
257
258 /*
259 * Allocate a new channel object and set its type and socket. This will cause
260 * remote_name to be freed.
261 */
262 Channel *
263 channel_new(char *ctype, int type, int rfd, int wfd, int efd,
264 u_int window, u_int maxpack, int extusage, char *remote_name, int nonblock)
265 {
266 int found;
267 u_int i;
268 Channel *c;
269
270 /* Do initial allocation if this is the first call. */
271 if (channels_alloc == 0) {
272 channels_alloc = 10;
273 channels = xcalloc(channels_alloc, sizeof(Channel *));
274 for (i = 0; i < channels_alloc; i++)
275 channels[i] = NULL;
276 }
277 /* Try to find a free slot where to put the new channel. */
278 for (found = -1, i = 0; i < channels_alloc; i++)
279 if (channels[i] == NULL) {
280 /* Found a free slot. */
281 found = (int)i;
282 break;
283 }
284 if (found < 0) {
285 /* There are no free slots. Take last+1 slot and expand the array. */
286 found = channels_alloc;
287 if (channels_alloc > 10000)
288 fatal("channel_new: internal error: channels_alloc %d "
289 "too big.", channels_alloc);
290 channels = xrealloc(channels, channels_alloc + 10,
291 sizeof(Channel *));
292 channels_alloc += 10;
293 debug2("channel: expanding %d", channels_alloc);
294 for (i = found; i < channels_alloc; i++)
295 channels[i] = NULL;
296 }
297 /* Initialize and return new channel. */
298 c = channels[found] = xcalloc(1, sizeof(Channel));
299 buffer_init(&c->input);
300 buffer_init(&c->output);
301 buffer_init(&c->extended);
302 c->path = NULL;
303 c->ostate = CHAN_OUTPUT_OPEN;
304 c->istate = CHAN_INPUT_OPEN;
305 c->flags = 0;
306 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock, 0);
307 c->self = found;
308 c->type = type;
309 c->ctype = ctype;
310 c->local_window = window;
311 c->local_window_max = window;
312 c->local_consumed = 0;
313 c->local_maxpacket = maxpack;
314 c->dynamic_window = 0;
315 c->remote_id = -1;
316 c->remote_name = xstrdup(remote_name);
317 c->remote_window = 0;
318 c->remote_maxpacket = 0;
319 c->force_drain = 0;
320 c->single_connection = 0;
321 c->detach_user = NULL;
322 c->detach_close = 0;
323 c->open_confirm = NULL;
324 c->open_confirm_ctx = NULL;
325 c->input_filter = NULL;
326 c->output_filter = NULL;
327 c->filter_ctx = NULL;
328 c->filter_cleanup = NULL;
329 TAILQ_INIT(&c->status_confirms);
330 debug("channel %d: new [%s]", found, remote_name);
331 return c;
332 }
333
334 static int
335 channel_find_maxfd(void)
336 {
337 u_int i;
338 int max = 0;
339 Channel *c;
340
341 for (i = 0; i < channels_alloc; i++) {
342 c = channels[i];
343 if (c != NULL) {
344 max = MAX(max, c->rfd);
345 max = MAX(max, c->wfd);
346 max = MAX(max, c->efd);
347 }
348 }
349 return max;
350 }
351
352 int
353 channel_close_fd(int *fdp)
354 {
355 int ret = 0, fd = *fdp;
356
357 if (fd != -1) {
358 ret = close(fd);
359 *fdp = -1;
360 if (fd == channel_max_fd)
361 channel_max_fd = channel_find_maxfd();
362 }
363 return ret;
364 }
365
366 /* Close all channel fd/socket. */
367 static void
368 channel_close_fds(Channel *c)
369 {
370 debug3("channel %d: close_fds r %d w %d e %d c %d",
371 c->self, c->rfd, c->wfd, c->efd, c->ctl_fd);
372
373 channel_close_fd(&c->sock);
374 channel_close_fd(&c->ctl_fd);
375 channel_close_fd(&c->rfd);
376 channel_close_fd(&c->wfd);
377 channel_close_fd(&c->efd);
378 }
379
380 /* Free the channel and close its fd/socket. */
381 void
382 channel_free(Channel *c)
383 {
384 char *s;
385 u_int i, n;
386 struct channel_confirm *cc;
387
388 for (n = 0, i = 0; i < channels_alloc; i++)
389 if (channels[i])
390 n++;
391 debug("channel %d: free: %s, nchannels %u", c->self,
392 c->remote_name ? c->remote_name : "???", n);
393
394 s = channel_open_message();
395 debug3("channel %d: status: %s", c->self, s);
396 xfree(s);
397
398 if (c->sock != -1)
399 shutdown(c->sock, SHUT_RDWR);
400 if (c->ctl_fd != -1)
401 shutdown(c->ctl_fd, SHUT_RDWR);
402 channel_close_fds(c);
403 buffer_free(&c->input);
404 buffer_free(&c->output);
405 buffer_free(&c->extended);
406 if (c->remote_name) {
407 xfree(c->remote_name);
408 c->remote_name = NULL;
409 }
410 if (c->path) {
411 xfree(c->path);
412 c->path = NULL;
413 }
414 while ((cc = TAILQ_FIRST(&c->status_confirms)) != NULL) {
415 if (cc->abandon_cb != NULL)
416 cc->abandon_cb(c, cc->ctx);
417 TAILQ_REMOVE(&c->status_confirms, cc, entry);
418 bzero(cc, sizeof(*cc));
419 xfree(cc);
420 }
421 if (c->filter_cleanup != NULL && c->filter_ctx != NULL)
422 c->filter_cleanup(c->self, c->filter_ctx);
423 channels[c->self] = NULL;
424 xfree(c);
425 }
426
427 void
428 channel_free_all(void)
429 {
430 u_int i;
431
432 for (i = 0; i < channels_alloc; i++)
433 if (channels[i] != NULL)
434 channel_free(channels[i]);
435 }
436
437 /*
438 * Closes the sockets/fds of all channels. This is used to close extra file
439 * descriptors after a fork.
440 */
441 void
442 channel_close_all(void)
443 {
444 u_int i;
445
446 for (i = 0; i < channels_alloc; i++)
447 if (channels[i] != NULL)
448 channel_close_fds(channels[i]);
449 }
450
451 /*
452 * Stop listening to channels.
453 */
454 void
455 channel_stop_listening(void)
456 {
457 u_int i;
458 Channel *c;
459
460 for (i = 0; i < channels_alloc; i++) {
461 c = channels[i];
462 if (c != NULL) {
463 switch (c->type) {
464 case SSH_CHANNEL_AUTH_SOCKET:
465 case SSH_CHANNEL_PORT_LISTENER:
466 case SSH_CHANNEL_RPORT_LISTENER:
467 case SSH_CHANNEL_X11_LISTENER:
468 channel_close_fd(&c->sock);
469 channel_free(c);
470 break;
471 }
472 }
473 }
474 }
475
476 /*
477 * Returns true if no channel has too much buffered data, and false if one or
478 * more channel is overfull.
479 */
480 int
481 channel_not_very_much_buffered_data(void)
482 {
483 u_int i;
484 Channel *c;
485
486 for (i = 0; i < channels_alloc; i++) {
487 c = channels[i];
488 if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
489 #if 0
490 if (!compat20 &&
491 buffer_len(&c->input) > packet_get_maxsize()) {
492 debug2("channel %d: big input buffer %d",
493 c->self, buffer_len(&c->input));
494 return 0;
495 }
496 #endif
497 if (buffer_len(&c->output) > packet_get_maxsize()) {
498 debug2("channel %d: big output buffer %u > %u",
499 c->self, buffer_len(&c->output),
500 packet_get_maxsize());
501 return 0;
502 }
503 }
504 }
505 return 1;
506 }
507
508 /* Returns true if any channel is still open. */
509 int
510 channel_still_open(void)
511 {
512 u_int i;
513 Channel *c;
514
515 for (i = 0; i < channels_alloc; i++) {
516 c = channels[i];
517 if (c == NULL)
518 continue;
519 switch (c->type) {
520 case SSH_CHANNEL_X11_LISTENER:
521 case SSH_CHANNEL_PORT_LISTENER:
522 case SSH_CHANNEL_RPORT_LISTENER:
523 case SSH_CHANNEL_CLOSED:
524 case SSH_CHANNEL_AUTH_SOCKET:
525 case SSH_CHANNEL_DYNAMIC:
526 case SSH_CHANNEL_CONNECTING:
527 case SSH_CHANNEL_ZOMBIE:
528 continue;
529 case SSH_CHANNEL_LARVAL:
530 if (!compat20)
531 fatal("cannot happen: SSH_CHANNEL_LARVAL");
532 continue;
533 case SSH_CHANNEL_OPENING:
534 case SSH_CHANNEL_OPEN:
535 case SSH_CHANNEL_X11_OPEN:
536 return 1;
537 case SSH_CHANNEL_INPUT_DRAINING:
538 case SSH_CHANNEL_OUTPUT_DRAINING:
539 if (!compat13)
540 fatal("cannot happen: OUT_DRAIN");
541 return 1;
542 default:
543 fatal("channel_still_open: bad channel type %d", c->type);
544 /* NOTREACHED */
545 }
546 }
547 return 0;
548 }
549
550 /* Returns the id of an open channel suitable for keepaliving */
551 int
552 channel_find_open(void)
553 {
554 u_int i;
555 Channel *c;
556
557 for (i = 0; i < channels_alloc; i++) {
558 c = channels[i];
559 if (c == NULL || c->remote_id < 0)
560 continue;
561 switch (c->type) {
562 case SSH_CHANNEL_CLOSED:
563 case SSH_CHANNEL_DYNAMIC:
564 case SSH_CHANNEL_X11_LISTENER:
565 case SSH_CHANNEL_PORT_LISTENER:
566 case SSH_CHANNEL_RPORT_LISTENER:
567 case SSH_CHANNEL_OPENING:
568 case SSH_CHANNEL_CONNECTING:
569 case SSH_CHANNEL_ZOMBIE:
570 continue;
571 case SSH_CHANNEL_LARVAL:
572 case SSH_CHANNEL_AUTH_SOCKET:
573 case SSH_CHANNEL_OPEN:
574 case SSH_CHANNEL_X11_OPEN:
575 return i;
576 case SSH_CHANNEL_INPUT_DRAINING:
577 case SSH_CHANNEL_OUTPUT_DRAINING:
578 if (!compat13)
579 fatal("cannot happen: OUT_DRAIN");
580 return i;
581 default:
582 fatal("channel_find_open: bad channel type %d", c->type);
583 /* NOTREACHED */
584 }
585 }
586 return -1;
587 }
588
589
590 /*
591 * Returns a message describing the currently open forwarded connections,
592 * suitable for sending to the client. The message contains crlf pairs for
593 * newlines.
594 */
595 char *
596 channel_open_message(void)
597 {
598 Buffer buffer;
599 Channel *c;
600 char buf[1024], *cp;
601 u_int i;
602
603 buffer_init(&buffer);
604 snprintf(buf, sizeof buf, "The following connections are open:\r\n");
605 buffer_append(&buffer, buf, strlen(buf));
606 for (i = 0; i < channels_alloc; i++) {
607 c = channels[i];
608 if (c == NULL)
609 continue;
610 switch (c->type) {
611 case SSH_CHANNEL_X11_LISTENER:
612 case SSH_CHANNEL_PORT_LISTENER:
613 case SSH_CHANNEL_RPORT_LISTENER:
614 case SSH_CHANNEL_CLOSED:
615 case SSH_CHANNEL_AUTH_SOCKET:
616 case SSH_CHANNEL_ZOMBIE:
617 continue;
618 case SSH_CHANNEL_LARVAL:
619 case SSH_CHANNEL_OPENING:
620 case SSH_CHANNEL_CONNECTING:
621 case SSH_CHANNEL_DYNAMIC:
622 case SSH_CHANNEL_OPEN:
623 case SSH_CHANNEL_X11_OPEN:
624 case SSH_CHANNEL_INPUT_DRAINING:
625 case SSH_CHANNEL_OUTPUT_DRAINING:
626 snprintf(buf, sizeof buf,
627 " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d cfd %d)\r\n",
628 c->self, c->remote_name,
629 c->type, c->remote_id,
630 c->istate, buffer_len(&c->input),
631 c->ostate, buffer_len(&c->output),
632 c->rfd, c->wfd, c->ctl_fd);
633 buffer_append(&buffer, buf, strlen(buf));
634 continue;
635 default:
636 fatal("channel_open_message: bad channel type %d", c->type);
637 /* NOTREACHED */
638 }
639 }
640 buffer_append(&buffer, "\0", 1);
641 cp = xstrdup(buffer_ptr(&buffer));
642 buffer_free(&buffer);
643 return cp;
644 }
645
646 void
647 channel_send_open(int id)
648 {
649 Channel *c = channel_lookup(id);
650
651 if (c == NULL) {
652 logit("channel_send_open: %d: bad id", id);
653 return;
654 }
655 debug2("channel %d: send open", id);
656 packet_start(SSH2_MSG_CHANNEL_OPEN);
657 packet_put_cstring(c->ctype);
658 packet_put_int(c->self);
659 packet_put_int(c->local_window);
660 packet_put_int(c->local_maxpacket);
661 packet_send();
662 }
663
664 void
665 channel_request_start(int id, char *service, int wantconfirm)
666 {
667 Channel *c = channel_lookup(id);
668
669 if (c == NULL) {
670 logit("channel_request_start: %d: unknown channel id", id);
671 return;
672 }
673 debug2("channel %d: request %s confirm %d", id, service, wantconfirm);
674 packet_start(SSH2_MSG_CHANNEL_REQUEST);
675 packet_put_int(c->remote_id);
676 packet_put_cstring(service);
677 packet_put_char(wantconfirm);
678 }
679
680 void
681 channel_register_status_confirm(int id, channel_confirm_cb *cb,
682 channel_confirm_abandon_cb *abandon_cb, void *ctx)
683 {
684 struct channel_confirm *cc;
685 Channel *c;
686
687 if ((c = channel_lookup(id)) == NULL)
688 fatal("channel_register_expect: %d: bad id", id);
689
690 cc = xmalloc(sizeof(*cc));
691 cc->cb = cb;
692 cc->abandon_cb = abandon_cb;
693 cc->ctx = ctx;
694 TAILQ_INSERT_TAIL(&c->status_confirms, cc, entry);
695 }
696
697 void
698 channel_register_open_confirm(int id, channel_callback_fn *fn, void *ctx)
699 {
700 Channel *c = channel_lookup(id);
701
702 if (c == NULL) {
703 logit("channel_register_open_confirm: %d: bad id", id);
704 return;
705 }
706 c->open_confirm = fn;
707 c->open_confirm_ctx = ctx;
708 }
709
710 void
711 channel_register_cleanup(int id, channel_callback_fn *fn, int do_close)
712 {
713 Channel *c = channel_by_id(id);
714
715 if (c == NULL) {
716 logit("channel_register_cleanup: %d: bad id", id);
717 return;
718 }
719 c->detach_user = fn;
720 c->detach_close = do_close;
721 }
722
723 void
724 channel_cancel_cleanup(int id)
725 {
726 Channel *c = channel_by_id(id);
727
728 if (c == NULL) {
729 logit("channel_cancel_cleanup: %d: bad id", id);
730 return;
731 }
732 c->detach_user = NULL;
733 c->detach_close = 0;
734 }
735
736 void
737 channel_register_filter(int id, channel_infilter_fn *ifn,
738 channel_outfilter_fn *ofn, channel_filter_cleanup_fn *cfn, void *ctx)
739 {
740 Channel *c = channel_lookup(id);
741
742 if (c == NULL) {
743 logit("channel_register_filter: %d: bad id", id);
744 return;
745 }
746 c->input_filter = ifn;
747 c->output_filter = ofn;
748 c->filter_ctx = ctx;
749 c->filter_cleanup = cfn;
750 }
751
752 void
753 channel_set_fds(int id, int rfd, int wfd, int efd,
754 int extusage, int nonblock, int is_tty, u_int window_max)
755 {
756 Channel *c = channel_lookup(id);
757
758 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
759 fatal("channel_activate for non-larval channel %d.", id);
760 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock, is_tty);
761 c->type = SSH_CHANNEL_OPEN;
762 c->local_window = c->local_window_max = window_max;
763 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
764 packet_put_int(c->remote_id);
765 packet_put_int(c->local_window);
766 packet_send();
767 }
768
769 /*
770 * 'channel_pre*' are called just before select() to add any bits relevant to
771 * channels in the select bitmasks.
772 */
773 /*
774 * 'channel_post*': perform any appropriate operations for channels which
775 * have events pending.
776 */
777 typedef void chan_fn(Channel *c, fd_set *readset, fd_set *writeset);
778 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
779 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
780
781 /* ARGSUSED */
782 static void
783 channel_pre_listener(Channel *c, fd_set *readset, fd_set *writeset)
784 {
785 FD_SET(c->sock, readset);
786 }
787
788 /* ARGSUSED */
789 static void
790 channel_pre_connecting(Channel *c, fd_set *readset, fd_set *writeset)
791 {
792 debug3("channel %d: waiting for connection", c->self);
793 FD_SET(c->sock, writeset);
794 }
795
796 static int channel_tcpwinsz(void)
797 {
798 u_int32_t tcpwinsz = 0;
799 socklen_t optsz = sizeof(tcpwinsz);
800 int ret = -1;
801
802 /* if we aren't on a socket return 128KB*/
803 if(!packet_connection_is_on_socket())
804 return(128*1024);
805 ret = getsockopt(packet_get_connection_in(),
806 SOL_SOCKET, SO_RCVBUF, &tcpwinsz, &optsz);
807 /* return no more than 64MB */
808 if ((ret == 0) && tcpwinsz > BUFFER_MAX_LEN_HPN)
809 tcpwinsz = BUFFER_MAX_LEN_HPN;
810 debug2("tcpwinsz: %d for connection: %d", tcpwinsz,
811 packet_get_connection_in());
812 return(tcpwinsz);
813 }
814
815 static void
816 channel_pre_open_13(Channel *c, fd_set *readset, fd_set *writeset)
817 {
818 if (buffer_len(&c->input) < packet_get_maxsize())
819 FD_SET(c->sock, readset);
820 if (buffer_len(&c->output) > 0)
821 FD_SET(c->sock, writeset);
822 }
823
824 static void
825 channel_pre_open(Channel *c, fd_set *readset, fd_set *writeset)
826 {
827 u_int limit = compat20 ? c->remote_window : packet_get_maxsize();
828
829 /* check buffer limits */
830 if ((!c->tcpwinsz) || (c->dynamic_window > 0))
831 c->tcpwinsz = channel_tcpwinsz();
832
833 limit = MIN(limit, 2 * c->tcpwinsz);
834
835 if (c->istate == CHAN_INPUT_OPEN &&
836 limit > 0 &&
837 buffer_len(&c->input) < limit &&
838 buffer_check_alloc(&c->input, CHAN_RBUF))
839 FD_SET(c->rfd, readset);
840 if (c->ostate == CHAN_OUTPUT_OPEN ||
841 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
842 if (buffer_len(&c->output) > 0) {
843 FD_SET(c->wfd, writeset);
844 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
845 if (CHANNEL_EFD_OUTPUT_ACTIVE(c))
846 debug2("channel %d: obuf_empty delayed efd %d/(%d)",
847 c->self, c->efd, buffer_len(&c->extended));
848 else
849 chan_obuf_empty(c);
850 }
851 }
852 /** XXX check close conditions, too */
853 if (compat20 && c->efd != -1 &&
854 !(c->istate == CHAN_INPUT_CLOSED && c->ostate == CHAN_OUTPUT_CLOSED)) {
855 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
856 buffer_len(&c->extended) > 0)
857 FD_SET(c->efd, writeset);
858 else if (!(c->flags & CHAN_EOF_SENT) &&
859 c->extended_usage == CHAN_EXTENDED_READ &&
860 buffer_len(&c->extended) < c->remote_window)
861 FD_SET(c->efd, readset);
862 }
863 /* XXX: What about efd? races? */
864 if (compat20 && c->ctl_fd != -1 &&
865 c->istate == CHAN_INPUT_OPEN && c->ostate == CHAN_OUTPUT_OPEN)
866 FD_SET(c->ctl_fd, readset);
867 }
868
869 /* ARGSUSED */
870 static void
871 channel_pre_input_draining(Channel *c, fd_set *readset, fd_set *writeset)
872 {
873 if (buffer_len(&c->input) == 0) {
874 packet_start(SSH_MSG_CHANNEL_CLOSE);
875 packet_put_int(c->remote_id);
876 packet_send();
877 c->type = SSH_CHANNEL_CLOSED;
878 debug2("channel %d: closing after input drain.", c->self);
879 }
880 }
881
882 /* ARGSUSED */
883 static void
884 channel_pre_output_draining(Channel *c, fd_set *readset, fd_set *writeset)
885 {
886 if (buffer_len(&c->output) == 0)
887 chan_mark_dead(c);
888 else
889 FD_SET(c->sock, writeset);
890 }
891
892 /*
893 * This is a special state for X11 authentication spoofing. An opened X11
894 * connection (when authentication spoofing is being done) remains in this
895 * state until the first packet has been completely read. The authentication
896 * data in that packet is then substituted by the real data if it matches the
897 * fake data, and the channel is put into normal mode.
898 * XXX All this happens at the client side.
899 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
900 */
901 static int
902 x11_open_helper(Buffer *b)
903 {
904 u_char *ucp;
905 u_int proto_len, data_len;
906
907 /* Check if the fixed size part of the packet is in buffer. */
908 if (buffer_len(b) < 12)
909 return 0;
910
911 /* Parse the lengths of variable-length fields. */
912 ucp = buffer_ptr(b);
913 if (ucp[0] == 0x42) { /* Byte order MSB first. */
914 proto_len = 256 * ucp[6] + ucp[7];
915 data_len = 256 * ucp[8] + ucp[9];
916 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
917 proto_len = ucp[6] + 256 * ucp[7];
918 data_len = ucp[8] + 256 * ucp[9];
919 } else {
920 debug2("Initial X11 packet contains bad byte order byte: 0x%x",
921 ucp[0]);
922 return -1;
923 }
924
925 /* Check if the whole packet is in buffer. */
926 if (buffer_len(b) <
927 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
928 return 0;
929
930 /* Check if authentication protocol matches. */
931 if (proto_len != strlen(x11_saved_proto) ||
932 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
933 debug2("X11 connection uses different authentication protocol.");
934 return -1;
935 }
936 /* Check if authentication data matches our fake data. */
937 if (data_len != x11_fake_data_len ||
938 memcmp(ucp + 12 + ((proto_len + 3) & ~3),
939 x11_fake_data, x11_fake_data_len) != 0) {
940 debug2("X11 auth data does not match fake data.");
941 return -1;
942 }
943 /* Check fake data length */
944 if (x11_fake_data_len != x11_saved_data_len) {
945 error("X11 fake_data_len %d != saved_data_len %d",
946 x11_fake_data_len, x11_saved_data_len);
947 return -1;
948 }
949 /*
950 * Received authentication protocol and data match
951 * our fake data. Substitute the fake data with real
952 * data.
953 */
954 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
955 x11_saved_data, x11_saved_data_len);
956 return 1;
957 }
958
959 static void
960 channel_pre_x11_open_13(Channel *c, fd_set *readset, fd_set *writeset)
961 {
962 int ret = x11_open_helper(&c->output);
963
964 if (ret == 1) {
965 /* Start normal processing for the channel. */
966 c->type = SSH_CHANNEL_OPEN;
967 channel_pre_open_13(c, readset, writeset);
968 } else if (ret == -1) {
969 /*
970 * We have received an X11 connection that has bad
971 * authentication information.
972 */
973 logit("X11 connection rejected because of wrong authentication.");
974 buffer_clear(&c->input);
975 buffer_clear(&c->output);
976 channel_close_fd(&c->sock);
977 c->sock = -1;
978 c->type = SSH_CHANNEL_CLOSED;
979 packet_start(SSH_MSG_CHANNEL_CLOSE);
980 packet_put_int(c->remote_id);
981 packet_send();
982 }
983 }
984
985 static void
986 channel_pre_x11_open(Channel *c, fd_set *readset, fd_set *writeset)
987 {
988 int ret = x11_open_helper(&c->output);
989
990 /* c->force_drain = 1; */
991
992 if (ret == 1) {
993 c->type = SSH_CHANNEL_OPEN;
994 channel_pre_open(c, readset, writeset);
995 } else if (ret == -1) {
996 logit("X11 connection rejected because of wrong authentication.");
997 debug2("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
998 chan_read_failed(c);
999 buffer_clear(&c->input);
1000 chan_ibuf_empty(c);
1001 buffer_clear(&c->output);
1002 /* for proto v1, the peer will send an IEOF */
1003 if (compat20)
1004 chan_write_failed(c);
1005 else
1006 c->type = SSH_CHANNEL_OPEN;
1007 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
1008 }
1009 }
1010
1011 /* try to decode a socks4 header */
1012 /* ARGSUSED */
1013 static int
1014 channel_decode_socks4(Channel *c, fd_set *readset, fd_set *writeset)
1015 {
1016 char *p, *host;
1017 u_int len, have, i, found, need;
1018 char username[256];
1019 struct {
1020 u_int8_t version;
1021 u_int8_t command;
1022 u_int16_t dest_port;
1023 struct in_addr dest_addr;
1024 } s4_req, s4_rsp;
1025
1026 debug2("channel %d: decode socks4", c->self);
1027
1028 have = buffer_len(&c->input);
1029 len = sizeof(s4_req);
1030 if (have < len)
1031 return 0;
1032 p = buffer_ptr(&c->input);
1033
1034 need = 1;
1035 /* SOCKS4A uses an invalid IP address 0.0.0.x */
1036 if (p[4] == 0 && p[5] == 0 && p[6] == 0 && p[7] != 0) {
1037 debug2("channel %d: socks4a request", c->self);
1038 /* ... and needs an extra string (the hostname) */
1039 need = 2;
1040 }
1041 /* Check for terminating NUL on the string(s) */
1042 for (found = 0, i = len; i < have; i++) {
1043 if (p[i] == '\0') {
1044 found++;
1045 if (found == need)
1046 break;
1047 }
1048 if (i > 1024) {
1049 /* the peer is probably sending garbage */
1050 debug("channel %d: decode socks4: too long",
1051 c->self);
1052 return -1;
1053 }
1054 }
1055 if (found < need)
1056 return 0;
1057 buffer_get(&c->input, (char *)&s4_req.version, 1);
1058 buffer_get(&c->input, (char *)&s4_req.command, 1);
1059 buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
1060 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
1061 have = buffer_len(&c->input);
1062 p = buffer_ptr(&c->input);
1063 len = strlen(p);
1064 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
1065 len++; /* trailing '\0' */
1066 if (len > have)
1067 fatal("channel %d: decode socks4: len %d > have %d",
1068 c->self, len, have);
1069 strlcpy(username, p, sizeof(username));
1070 buffer_consume(&c->input, len);
1071
1072 if (c->path != NULL) {
1073 xfree(c->path);
1074 c->path = NULL;
1075 }
1076 if (need == 1) { /* SOCKS4: one string */
1077 host = inet_ntoa(s4_req.dest_addr);
1078 c->path = xstrdup(host);
1079 } else { /* SOCKS4A: two strings */
1080 have = buffer_len(&c->input);
1081 p = buffer_ptr(&c->input);
1082 len = strlen(p);
1083 debug2("channel %d: decode socks4a: host %s/%d",
1084 c->self, p, len);
1085 len++; /* trailing '\0' */
1086 if (len > have)
1087 fatal("channel %d: decode socks4a: len %d > have %d",
1088 c->self, len, have);
1089 if (len > NI_MAXHOST) {
1090 error("channel %d: hostname \"%.100s\" too long",
1091 c->self, p);
1092 return -1;
1093 }
1094 c->path = xstrdup(p);
1095 buffer_consume(&c->input, len);
1096 }
1097 c->host_port = ntohs(s4_req.dest_port);
1098
1099 debug2("channel %d: dynamic request: socks4 host %s port %u command %u",
1100 c->self, c->path, c->host_port, s4_req.command);
1101
1102 if (s4_req.command != 1) {
1103 debug("channel %d: cannot handle: %s cn %d",
1104 c->self, need == 1 ? "SOCKS4" : "SOCKS4A", s4_req.command);
1105 return -1;
1106 }
1107 s4_rsp.version = 0; /* vn: 0 for reply */
1108 s4_rsp.command = 90; /* cd: req granted */
1109 s4_rsp.dest_port = 0; /* ignored */
1110 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
1111 buffer_append(&c->output, &s4_rsp, sizeof(s4_rsp));
1112 return 1;
1113 }
1114
1115 /* try to decode a socks5 header */
1116 #define SSH_SOCKS5_AUTHDONE 0x1000
1117 #define SSH_SOCKS5_NOAUTH 0x00
1118 #define SSH_SOCKS5_IPV4 0x01
1119 #define SSH_SOCKS5_DOMAIN 0x03
1120 #define SSH_SOCKS5_IPV6 0x04
1121 #define SSH_SOCKS5_CONNECT 0x01
1122 #define SSH_SOCKS5_SUCCESS 0x00
1123
1124 /* ARGSUSED */
1125 static int
1126 channel_decode_socks5(Channel *c, fd_set *readset, fd_set *writeset)
1127 {
1128 struct {
1129 u_int8_t version;
1130 u_int8_t command;
1131 u_int8_t reserved;
1132 u_int8_t atyp;
1133 } s5_req, s5_rsp;
1134 u_int16_t dest_port;
1135 u_char *p, dest_addr[255+1], ntop[INET6_ADDRSTRLEN];
1136 u_int have, need, i, found, nmethods, addrlen, af;
1137
1138 debug2("channel %d: decode socks5", c->self);
1139 p = buffer_ptr(&c->input);
1140 if (p[0] != 0x05)
1141 return -1;
1142 have = buffer_len(&c->input);
1143 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) {
1144 /* format: ver | nmethods | methods */
1145 if (have < 2)
1146 return 0;
1147 nmethods = p[1];
1148 if (have < nmethods + 2)
1149 return 0;
1150 /* look for method: "NO AUTHENTICATION REQUIRED" */
1151 for (found = 0, i = 2; i < nmethods + 2; i++) {
1152 if (p[i] == SSH_SOCKS5_NOAUTH) {
1153 found = 1;
1154 break;
1155 }
1156 }
1157 if (!found) {
1158 debug("channel %d: method SSH_SOCKS5_NOAUTH not found",
1159 c->self);
1160 return -1;
1161 }
1162 buffer_consume(&c->input, nmethods + 2);
1163 buffer_put_char(&c->output, 0x05); /* version */
1164 buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH); /* method */
1165 FD_SET(c->sock, writeset);
1166 c->flags |= SSH_SOCKS5_AUTHDONE;
1167 debug2("channel %d: socks5 auth done", c->self);
1168 return 0; /* need more */
1169 }
1170 debug2("channel %d: socks5 post auth", c->self);
1171 if (have < sizeof(s5_req)+1)
1172 return 0; /* need more */
1173 memcpy(&s5_req, p, sizeof(s5_req));
1174 if (s5_req.version != 0x05 ||
1175 s5_req.command != SSH_SOCKS5_CONNECT ||
1176 s5_req.reserved != 0x00) {
1177 debug2("channel %d: only socks5 connect supported", c->self);
1178 return -1;
1179 }
1180 switch (s5_req.atyp){
1181 case SSH_SOCKS5_IPV4:
1182 addrlen = 4;
1183 af = AF_INET;
1184 break;
1185 case SSH_SOCKS5_DOMAIN:
1186 addrlen = p[sizeof(s5_req)];
1187 af = -1;
1188 break;
1189 case SSH_SOCKS5_IPV6:
1190 addrlen = 16;
1191 af = AF_INET6;
1192 break;
1193 default:
1194 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp);
1195 return -1;
1196 }
1197 need = sizeof(s5_req) + addrlen + 2;
1198 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1199 need++;
1200 if (have < need)
1201 return 0;
1202 buffer_consume(&c->input, sizeof(s5_req));
1203 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1204 buffer_consume(&c->input, 1); /* host string length */
1205 buffer_get(&c->input, (char *)&dest_addr, addrlen);
1206 buffer_get(&c->input, (char *)&dest_port, 2);
1207 dest_addr[addrlen] = '\0';
1208 if (c->path != NULL) {
1209 xfree(c->path);
1210 c->path = NULL;
1211 }
1212 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) {
1213 if (addrlen >= NI_MAXHOST) {
1214 error("channel %d: dynamic request: socks5 hostname "
1215 "\"%.100s\" too long", c->self, dest_addr);
1216 return -1;
1217 }
1218 c->path = xstrdup(dest_addr);
1219 } else {
1220 if (inet_ntop(af, dest_addr, ntop, sizeof(ntop)) == NULL)
1221 return -1;
1222 c->path = xstrdup(ntop);
1223 }
1224 c->host_port = ntohs(dest_port);
1225
1226 debug2("channel %d: dynamic request: socks5 host %s port %u command %u",
1227 c->self, c->path, c->host_port, s5_req.command);
1228
1229 s5_rsp.version = 0x05;
1230 s5_rsp.command = SSH_SOCKS5_SUCCESS;
1231 s5_rsp.reserved = 0; /* ignored */
1232 s5_rsp.atyp = SSH_SOCKS5_IPV4;
1233 ((struct in_addr *)&dest_addr)->s_addr = INADDR_ANY;
1234 dest_port = 0; /* ignored */
1235
1236 buffer_append(&c->output, &s5_rsp, sizeof(s5_rsp));
1237 buffer_append(&c->output, &dest_addr, sizeof(struct in_addr));
1238 buffer_append(&c->output, &dest_port, sizeof(dest_port));
1239 return 1;
1240 }
1241
1242 /* dynamic port forwarding */
1243 static void
1244 channel_pre_dynamic(Channel *c, fd_set *readset, fd_set *writeset)
1245 {
1246 u_char *p;
1247 u_int have;
1248 int ret;
1249
1250 have = buffer_len(&c->input);
1251 c->delayed = 0;
1252 debug2("channel %d: pre_dynamic: have %d", c->self, have);
1253 /* buffer_dump(&c->input); */
1254 /* check if the fixed size part of the packet is in buffer. */
1255 if (have < 3) {
1256 /* need more */
1257 FD_SET(c->sock, readset);
1258 return;
1259 }
1260 /* try to guess the protocol */
1261 p = buffer_ptr(&c->input);
1262 switch (p[0]) {
1263 case 0x04:
1264 ret = channel_decode_socks4(c, readset, writeset);
1265 break;
1266 case 0x05:
1267 ret = channel_decode_socks5(c, readset, writeset);
1268 break;
1269 default:
1270 ret = -1;
1271 break;
1272 }
1273 if (ret < 0) {
1274 chan_mark_dead(c);
1275 } else if (ret == 0) {
1276 debug2("channel %d: pre_dynamic: need more", c->self);
1277 /* need more */
1278 FD_SET(c->sock, readset);
1279 } else {
1280 /* switch to the next state */
1281 c->type = SSH_CHANNEL_OPENING;
1282 port_open_helper(c, "direct-tcpip");
1283 }
1284 }
1285
1286 /* This is our fake X11 server socket. */
1287 /* ARGSUSED */
1288 static void
1289 channel_post_x11_listener(Channel *c, fd_set *readset, fd_set *writeset)
1290 {
1291 Channel *nc;
1292 struct sockaddr_storage addr;
1293 int newsock;
1294 socklen_t addrlen;
1295 char buf[16384], *remote_ipaddr;
1296 int remote_port;
1297
1298 if (FD_ISSET(c->sock, readset)) {
1299 debug("X11 connection requested.");
1300 addrlen = sizeof(addr);
1301 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1302 if (c->single_connection) {
1303 debug2("single_connection: closing X11 listener.");
1304 channel_close_fd(&c->sock);
1305 chan_mark_dead(c);
1306 }
1307 if (newsock < 0) {
1308 error("accept: %.100s", strerror(errno));
1309 return;
1310 }
1311 set_nodelay(newsock);
1312 remote_ipaddr = get_peer_ipaddr(newsock);
1313 remote_port = get_peer_port(newsock);
1314 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1315 remote_ipaddr, remote_port);
1316
1317 nc = channel_new("accepted x11 socket",
1318 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1319 c->local_window_max, c->local_maxpacket, 0, buf, 1);
1320 if (compat20) {
1321 packet_start(SSH2_MSG_CHANNEL_OPEN);
1322 packet_put_cstring("x11");
1323 packet_put_int(nc->self);
1324 packet_put_int(nc->local_window_max);
1325 packet_put_int(nc->local_maxpacket);
1326 /* originator ipaddr and port */
1327 packet_put_cstring(remote_ipaddr);
1328 if (datafellows & SSH_BUG_X11FWD) {
1329 debug2("ssh2 x11 bug compat mode");
1330 } else {
1331 packet_put_int(remote_port);
1332 }
1333 packet_send();
1334 } else {
1335 packet_start(SSH_SMSG_X11_OPEN);
1336 packet_put_int(nc->self);
1337 if (packet_get_protocol_flags() &
1338 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1339 packet_put_cstring(buf);
1340 packet_send();
1341 }
1342 xfree(remote_ipaddr);
1343 }
1344 }
1345
1346 static void
1347 port_open_helper(Channel *c, char *rtype)
1348 {
1349 int direct;
1350 char buf[1024];
1351 char *remote_ipaddr = get_peer_ipaddr(c->sock);
1352 int remote_port = get_peer_port(c->sock);
1353
1354 direct = (strcmp(rtype, "direct-tcpip") == 0);
1355
1356 snprintf(buf, sizeof buf,
1357 "%s: listening port %d for %.100s port %d, "
1358 "connect from %.200s port %d",
1359 rtype, c->listening_port, c->path, c->host_port,
1360 remote_ipaddr, remote_port);
1361
1362 xfree(c->remote_name);
1363 c->remote_name = xstrdup(buf);
1364
1365 if (compat20) {
1366 packet_start(SSH2_MSG_CHANNEL_OPEN);
1367 packet_put_cstring(rtype);
1368 packet_put_int(c->self);
1369 packet_put_int(c->local_window_max);
1370 packet_put_int(c->local_maxpacket);
1371 if (direct) {
1372 /* target host, port */
1373 packet_put_cstring(c->path);
1374 packet_put_int(c->host_port);
1375 } else {
1376 /* listen address, port */
1377 packet_put_cstring(c->path);
1378 packet_put_int(c->listening_port);
1379 }
1380 /* originator host and port */
1381 packet_put_cstring(remote_ipaddr);
1382 packet_put_int((u_int)remote_port);
1383 packet_send();
1384 } else {
1385 packet_start(SSH_MSG_PORT_OPEN);
1386 packet_put_int(c->self);
1387 packet_put_cstring(c->path);
1388 packet_put_int(c->host_port);
1389 if (packet_get_protocol_flags() &
1390 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1391 packet_put_cstring(c->remote_name);
1392 packet_send();
1393 }
1394 xfree(remote_ipaddr);
1395 }
1396
1397 static void
1398 channel_set_reuseaddr(int fd)
1399 {
1400 int on = 1;
1401
1402 /*
1403 * Set socket options.
1404 * Allow local port reuse in TIME_WAIT.
1405 */
1406 if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1)
1407 error("setsockopt SO_REUSEADDR fd %d: %s", fd, strerror(errno));
1408 }
1409
1410 /*
1411 * This socket is listening for connections to a forwarded TCP/IP port.
1412 */
1413 /* ARGSUSED */
1414 static void
1415 channel_post_port_listener(Channel *c, fd_set *readset, fd_set *writeset)
1416 {
1417 Channel *nc;
1418 struct sockaddr_storage addr;
1419 int newsock, nextstate;
1420 socklen_t addrlen;
1421 char *rtype;
1422
1423 if (FD_ISSET(c->sock, readset)) {
1424 debug("Connection to port %d forwarding "
1425 "to %.100s port %d requested.",
1426 c->listening_port, c->path, c->host_port);
1427
1428 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1429 nextstate = SSH_CHANNEL_OPENING;
1430 rtype = "forwarded-tcpip";
1431 } else {
1432 if (c->host_port == 0) {
1433 nextstate = SSH_CHANNEL_DYNAMIC;
1434 rtype = "dynamic-tcpip";
1435 } else {
1436 nextstate = SSH_CHANNEL_OPENING;
1437 rtype = "direct-tcpip";
1438 }
1439 }
1440
1441 addrlen = sizeof(addr);
1442 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1443 if (newsock < 0) {
1444 error("accept: %.100s", strerror(errno));
1445 return;
1446 }
1447 set_nodelay(newsock);
1448 nc = channel_new(rtype, nextstate, newsock, newsock, -1,
1449 c->local_window_max, c->local_maxpacket, 0, rtype, 1);
1450 nc->listening_port = c->listening_port;
1451 nc->host_port = c->host_port;
1452 if (c->path != NULL)
1453 nc->path = xstrdup(c->path);
1454
1455 if (nextstate == SSH_CHANNEL_DYNAMIC) {
1456 /*
1457 * do not call the channel_post handler until
1458 * this flag has been reset by a pre-handler.
1459 * otherwise the FD_ISSET calls might overflow
1460 */
1461 nc->delayed = 1;
1462 } else {
1463 port_open_helper(nc, rtype);
1464 }
1465 }
1466 }
1467
1468 /*
1469 * This is the authentication agent socket listening for connections from
1470 * clients.
1471 */
1472 /* ARGSUSED */
1473 static void
1474 channel_post_auth_listener(Channel *c, fd_set *readset, fd_set *writeset)
1475 {
1476 Channel *nc;
1477 int newsock;
1478 struct sockaddr_storage addr;
1479 socklen_t addrlen;
1480
1481 if (FD_ISSET(c->sock, readset)) {
1482 addrlen = sizeof(addr);
1483 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1484 if (newsock < 0) {
1485 error("accept from auth socket: %.100s", strerror(errno));
1486 return;
1487 }
1488 nc = channel_new("accepted auth socket",
1489 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1490 c->local_window_max, c->local_maxpacket,
1491 0, "accepted auth socket", 1);
1492 if (compat20) {
1493 packet_start(SSH2_MSG_CHANNEL_OPEN);
1494 packet_put_cstring("auth-agent@openssh.com");
1495 packet_put_int(nc->self);
1496 packet_put_int(c->local_window_max);
1497 packet_put_int(c->local_maxpacket);
1498 } else {
1499 packet_start(SSH_SMSG_AGENT_OPEN);
1500 packet_put_int(nc->self);
1501 }
1502 packet_send();
1503 }
1504 }
1505
1506 /* ARGSUSED */
1507 static void
1508 channel_post_connecting(Channel *c, fd_set *readset, fd_set *writeset)
1509 {
1510 int err = 0, sock;
1511 socklen_t sz = sizeof(err);
1512
1513 if (FD_ISSET(c->sock, writeset)) {
1514 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) {
1515 err = errno;
1516 error("getsockopt SO_ERROR failed");
1517 }
1518 if (err == 0) {
1519 debug("channel %d: connected to %s port %d",
1520 c->self, c->connect_ctx.host, c->connect_ctx.port);
1521 channel_connect_ctx_free(&c->connect_ctx);
1522 c->type = SSH_CHANNEL_OPEN;
1523 if (compat20) {
1524 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1525 packet_put_int(c->remote_id);
1526 packet_put_int(c->self);
1527 packet_put_int(c->local_window);
1528 packet_put_int(c->local_maxpacket);
1529 } else {
1530 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1531 packet_put_int(c->remote_id);
1532 packet_put_int(c->self);
1533 }
1534 } else {
1535 debug("channel %d: connection failed: %s",
1536 c->self, strerror(err));
1537 /* Try next address, if any */
1538 if ((sock = connect_next(&c->connect_ctx)) > 0) {
1539 close(c->sock);
1540 c->sock = c->rfd = c->wfd = sock;
1541 channel_max_fd = channel_find_maxfd();
1542 return;
1543 }
1544 /* Exhausted all addresses */
1545 error("connect_to %.100s port %d: failed.",
1546 c->connect_ctx.host, c->connect_ctx.port);
1547 channel_connect_ctx_free(&c->connect_ctx);
1548 if (compat20) {
1549 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1550 packet_put_int(c->remote_id);
1551 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1552 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1553 packet_put_cstring(strerror(err));
1554 packet_put_cstring("");
1555 }
1556 } else {
1557 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1558 packet_put_int(c->remote_id);
1559 }
1560 chan_mark_dead(c);
1561 }
1562 packet_send();
1563 }
1564 }
1565
1566 /* ARGSUSED */
1567 static int
1568 channel_handle_rfd(Channel *c, fd_set *readset, fd_set *writeset)
1569 {
1570 char buf[CHAN_RBUF];
1571 int len, force;
1572
1573 force = c->isatty && c->detach_close && c->istate != CHAN_INPUT_CLOSED;
1574 if (c->rfd != -1 && (force || FD_ISSET(c->rfd, readset))) {
1575 len = read(c->rfd, buf, sizeof(buf));
1576 if (len < 0 && (errno == EINTR || (errno == EAGAIN && !force)))
1577 return 1;
1578 if (len <= 0) {
1579 debug2("channel %d: read<=0 rfd %d len %d",
1580 c->self, c->rfd, len);
1581 if (c->type != SSH_CHANNEL_OPEN) {
1582 debug2("channel %d: not open", c->self);
1583 chan_mark_dead(c);
1584 return -1;
1585 } else if (compat13) {
1586 buffer_clear(&c->output);
1587 c->type = SSH_CHANNEL_INPUT_DRAINING;
1588 debug2("channel %d: input draining.", c->self);
1589 } else {
1590 chan_read_failed(c);
1591 }
1592 return -1;
1593 }
1594 if (c->input_filter != NULL) {
1595 if (c->input_filter(c, buf, len) == -1) {
1596 debug2("channel %d: filter stops", c->self);
1597 chan_read_failed(c);
1598 }
1599 } else if (c->datagram) {
1600 buffer_put_string(&c->input, buf, len);
1601 } else {
1602 buffer_append(&c->input, buf, len);
1603 }
1604 }
1605 return 1;
1606 }
1607
1608 /* ARGSUSED */
1609 static int
1610 channel_handle_wfd(Channel *c, fd_set *readset, fd_set *writeset)
1611 {
1612 struct termios tio;
1613 u_char *data = NULL, *buf;
1614 u_int dlen;
1615 int len;
1616
1617 /* Send buffered output data to the socket. */
1618 if (c->wfd != -1 &&
1619 FD_ISSET(c->wfd, writeset) &&
1620 buffer_len(&c->output) > 0) {
1621 if (c->output_filter != NULL) {
1622 if ((buf = c->output_filter(c, &data, &dlen)) == NULL) {
1623 debug2("channel %d: filter stops", c->self);
1624 if (c->type != SSH_CHANNEL_OPEN)
1625 chan_mark_dead(c);
1626 else
1627 chan_write_failed(c);
1628 return -1;
1629 }
1630 } else if (c->datagram) {
1631 buf = data = buffer_get_string(&c->output, &dlen);
1632 } else {
1633 buf = data = buffer_ptr(&c->output);
1634 dlen = buffer_len(&c->output);
1635 }
1636
1637 if (c->datagram) {
1638 /* ignore truncated writes, datagrams might get lost */
1639 c->local_consumed += dlen + 4;
1640 len = write(c->wfd, buf, dlen);
1641 xfree(data);
1642 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1643 return 1;
1644 if (len <= 0) {
1645 if (c->type != SSH_CHANNEL_OPEN)
1646 chan_mark_dead(c);
1647 else
1648 chan_write_failed(c);
1649 return -1;
1650 }
1651 return 1;
1652 }
1653
1654 len = write(c->wfd, buf, dlen);
1655 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1656 return 1;
1657 if (len <= 0) {
1658 if (c->type != SSH_CHANNEL_OPEN) {
1659 debug2("channel %d: not open", c->self);
1660 chan_mark_dead(c);
1661 return -1;
1662 } else if (compat13) {
1663 buffer_clear(&c->output);
1664 debug2("channel %d: input draining.", c->self);
1665 c->type = SSH_CHANNEL_INPUT_DRAINING;
1666 } else {
1667 chan_write_failed(c);
1668 }
1669 return -1;
1670 }
1671 if (compat20 && c->isatty && dlen >= 1 && buf[0] != '\r') {
1672 if (tcgetattr(c->wfd, &tio) == 0 &&
1673 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1674 /*
1675 * Simulate echo to reduce the impact of
1676 * traffic analysis. We need to match the
1677 * size of a SSH2_MSG_CHANNEL_DATA message
1678 * (4 byte channel id + buf)
1679 */
1680 packet_send_ignore(4 + len);
1681 packet_send();
1682 }
1683 }
1684 buffer_consume(&c->output, len);
1685 if (compat20 && len > 0) {
1686 c->local_consumed += len;
1687 }
1688 }
1689 return 1;
1690 }
1691
1692 static int
1693 channel_handle_efd(Channel *c, fd_set *readset, fd_set *writeset)
1694 {
1695 char buf[CHAN_RBUF];
1696 int len;
1697
1698 /** XXX handle drain efd, too */
1699 if (c->efd != -1) {
1700 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1701 FD_ISSET(c->efd, writeset) &&
1702 buffer_len(&c->extended) > 0) {
1703 len = write(c->efd, buffer_ptr(&c->extended),
1704 buffer_len(&c->extended));
1705 debug2("channel %d: written %d to efd %d",
1706 c->self, len, c->efd);
1707 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1708 return 1;
1709 if (len <= 0) {
1710 debug2("channel %d: closing write-efd %d",
1711 c->self, c->efd);
1712 channel_close_fd(&c->efd);
1713 } else {
1714 buffer_consume(&c->extended, len);
1715 c->local_consumed += len;
1716 }
1717 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
1718 FD_ISSET(c->efd, readset)) {
1719 len = read(c->efd, buf, sizeof(buf));
1720 debug2("channel %d: read %d from efd %d",
1721 c->self, len, c->efd);
1722 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1723 return 1;
1724 if (len <= 0) {
1725 debug2("channel %d: closing read-efd %d",
1726 c->self, c->efd);
1727 channel_close_fd(&c->efd);
1728 } else {
1729 buffer_append(&c->extended, buf, len);
1730 }
1731 }
1732 }
1733 return 1;
1734 }
1735
1736 /* ARGSUSED */
1737 static int
1738 channel_handle_ctl(Channel *c, fd_set *readset, fd_set *writeset)
1739 {
1740 char buf[16];
1741 int len;
1742
1743 /* Monitor control fd to detect if the slave client exits */
1744 if (c->ctl_fd != -1 && FD_ISSET(c->ctl_fd, readset)) {
1745 len = read(c->ctl_fd, buf, sizeof(buf));
1746 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1747 return 1;
1748 if (len <= 0) {
1749 debug2("channel %d: ctl read<=0", c->self);
1750 if (c->type != SSH_CHANNEL_OPEN) {
1751 debug2("channel %d: not open", c->self);
1752 chan_mark_dead(c);
1753 return -1;
1754 } else {
1755 chan_read_failed(c);
1756 chan_write_failed(c);
1757 }
1758 return -1;
1759 } else
1760 fatal("%s: unexpected data on ctl fd", __func__);
1761 }
1762 return 1;
1763 }
1764
1765 static int
1766 channel_check_window(Channel *c)
1767 {
1768 if (c->type == SSH_CHANNEL_OPEN &&
1769 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1770 ((c->local_window_max - c->local_window >
1771 c->local_maxpacket*3) ||
1772 c->local_window < c->local_window_max/2) &&
1773 c->local_consumed > 0) {
1774 u_int addition = 0;
1775 /* adjust max window size if we are in a dynamic environment */
1776 if (c->dynamic_window && (c->tcpwinsz > c->local_window_max)) {
1777 /* grow the window somewhat aggressively to maintain pressure */
1778 addition = 1.5*(c->tcpwinsz - c->local_window_max);
1779 c->local_window_max += addition;
1780 }
1781 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1782 packet_put_int(c->remote_id);
1783 packet_put_int(c->local_consumed + addition);
1784 packet_send();
1785 debug2("channel %d: window %d sent adjust %d",
1786 c->self, c->local_window,
1787 c->local_consumed);
1788 c->local_window += c->local_consumed + addition;
1789 c->local_consumed = 0;
1790 }
1791 return 1;
1792 }
1793
1794 static void
1795 channel_post_open(Channel *c, fd_set *readset, fd_set *writeset)
1796 {
1797 if (c->delayed)
1798 return;
1799 channel_handle_rfd(c, readset, writeset);
1800 channel_handle_wfd(c, readset, writeset);
1801 if (!compat20)
1802 return;
1803 channel_handle_efd(c, readset, writeset);
1804 channel_handle_ctl(c, readset, writeset);
1805 channel_check_window(c);
1806 }
1807
1808 /* ARGSUSED */
1809 static void
1810 channel_post_output_drain_13(Channel *c, fd_set *readset, fd_set *writeset)
1811 {
1812 int len;
1813
1814 /* Send buffered output data to the socket. */
1815 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1816 len = write(c->sock, buffer_ptr(&c->output),
1817 buffer_len(&c->output));
1818 if (len <= 0)
1819 buffer_clear(&c->output);
1820 else
1821 buffer_consume(&c->output, len);
1822 }
1823 }
1824
1825 static void
1826 channel_handler_init_20(void)
1827 {
1828 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1829 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1830 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1831 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
1832 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1833 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1834 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1835 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1836
1837 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1838 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1839 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
1840 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1841 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1842 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1843 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1844 }
1845
1846 static void
1847 channel_handler_init_13(void)
1848 {
1849 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
1850 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
1851 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1852 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1853 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1854 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
1855 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1856 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1857 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1858
1859 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1860 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1861 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1862 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1863 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
1864 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1865 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1866 }
1867
1868 static void
1869 channel_handler_init_15(void)
1870 {
1871 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1872 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1873 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1874 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1875 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1876 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1877 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1878
1879 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1880 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1881 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1882 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1883 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1884 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1885 }
1886
1887 static void
1888 channel_handler_init(void)
1889 {
1890 int i;
1891
1892 for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
1893 channel_pre[i] = NULL;
1894 channel_post[i] = NULL;
1895 }
1896 if (compat20)
1897 channel_handler_init_20();
1898 else if (compat13)
1899 channel_handler_init_13();
1900 else
1901 channel_handler_init_15();
1902 }
1903
1904 /* gc dead channels */
1905 static void
1906 channel_garbage_collect(Channel *c)
1907 {
1908 if (c == NULL)
1909 return;
1910 if (c->detach_user != NULL) {
1911 if (!chan_is_dead(c, c->detach_close))
1912 return;
1913 debug2("channel %d: gc: notify user", c->self);
1914 c->detach_user(c->self, NULL);
1915 /* if we still have a callback */
1916 if (c->detach_user != NULL)
1917 return;
1918 debug2("channel %d: gc: user detached", c->self);
1919 }
1920 if (!chan_is_dead(c, 1))
1921 return;
1922 debug2("channel %d: garbage collecting", c->self);
1923 channel_free(c);
1924 }
1925
1926 static void
1927 channel_handler(chan_fn *ftab[], fd_set *readset, fd_set *writeset)
1928 {
1929 static int did_init = 0;
1930 u_int i;
1931 Channel *c;
1932
1933 if (!did_init) {
1934 channel_handler_init();
1935 did_init = 1;
1936 }
1937 for (i = 0; i < channels_alloc; i++) {
1938 c = channels[i];
1939 if (c == NULL)
1940 continue;
1941 if (ftab[c->type] != NULL)
1942 (*ftab[c->type])(c, readset, writeset);
1943 channel_garbage_collect(c);
1944 }
1945 }
1946
1947 /*
1948 * Allocate/update select bitmasks and add any bits relevant to channels in
1949 * select bitmasks.
1950 */
1951 void
1952 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
1953 u_int *nallocp, int rekeying)
1954 {
1955 u_int n, sz, nfdset;
1956
1957 n = MAX(*maxfdp, channel_max_fd);
1958
1959 nfdset = howmany(n+1, NFDBITS);
1960 /* Explicitly test here, because xrealloc isn't always called */
1961 if (nfdset && SIZE_T_MAX / nfdset < sizeof(fd_mask))
1962 fatal("channel_prepare_select: max_fd (%d) is too large", n);
1963 sz = nfdset * sizeof(fd_mask);
1964
1965 /* perhaps check sz < nalloc/2 and shrink? */
1966 if (*readsetp == NULL || sz > *nallocp) {
1967 *readsetp = xrealloc(*readsetp, nfdset, sizeof(fd_mask));
1968 *writesetp = xrealloc(*writesetp, nfdset, sizeof(fd_mask));
1969 *nallocp = sz;
1970 }
1971 *maxfdp = n;
1972 memset(*readsetp, 0, sz);
1973 memset(*writesetp, 0, sz);
1974
1975 if (!rekeying)
1976 channel_handler(channel_pre, *readsetp, *writesetp);
1977 }
1978
1979 /*
1980 * After select, perform any appropriate operations for channels which have
1981 * events pending.
1982 */
1983 void
1984 channel_after_select(fd_set *readset, fd_set *writeset)
1985 {
1986 channel_handler(channel_post, readset, writeset);
1987 }
1988
1989
1990 /* If there is data to send to the connection, enqueue some of it now. */
1991 int
1992 channel_output_poll(void)
1993 {
1994 Channel *c;
1995 u_int i, len;
1996 int packet_length = 0;
1997
1998 for (i = 0; i < channels_alloc; i++) {
1999 c = channels[i];
2000 if (c == NULL)
2001 continue;
2002
2003 /*
2004 * We are only interested in channels that can have buffered
2005 * incoming data.
2006 */
2007 if (compat13) {
2008 if (c->type != SSH_CHANNEL_OPEN &&
2009 c->type != SSH_CHANNEL_INPUT_DRAINING)
2010 continue;
2011 } else {
2012 if (c->type != SSH_CHANNEL_OPEN)
2013 continue;
2014 }
2015 if (compat20 &&
2016 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
2017 /* XXX is this true? */
2018 debug3("channel %d: will not send data after close", c->self);
2019 continue;
2020 }
2021
2022 /* Get the amount of buffered data for this channel. */
2023 if ((c->istate == CHAN_INPUT_OPEN ||
2024 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
2025 (len = buffer_len(&c->input)) > 0) {
2026 if (c->datagram) {
2027 if (len > 0) {
2028 u_char *data;
2029 u_int dlen;
2030
2031 data = buffer_get_string(&c->input,
2032 &dlen);
2033 packet_start(SSH2_MSG_CHANNEL_DATA);
2034 packet_put_int(c->remote_id);
2035 packet_put_string(data, dlen);
2036 packet_length = packet_send();
2037 c->remote_window -= dlen + 4;
2038 xfree(data);
2039 }
2040 continue;
2041 }
2042 /*
2043 * Send some data for the other side over the secure
2044 * connection.
2045 */
2046 if (compat20) {
2047 if (len > c->remote_window)
2048 len = c->remote_window;
2049 if (len > c->remote_maxpacket)
2050 len = c->remote_maxpacket;
2051 } else {
2052 if (packet_is_interactive()) {
2053 if (len > 1024)
2054 len = 512;
2055 } else {
2056 /* Keep the packets at reasonable size. */
2057 if (len > packet_get_maxsize()/2)
2058 len = packet_get_maxsize()/2;
2059 }
2060 }
2061 if (len > 0) {
2062 packet_start(compat20 ?
2063 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
2064 packet_put_int(c->remote_id);
2065 packet_put_string(buffer_ptr(&c->input), len);
2066 packet_length = packet_send();
2067 buffer_consume(&c->input, len);
2068 c->remote_window -= len;
2069 }
2070 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
2071 if (compat13)
2072 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
2073 /*
2074 * input-buffer is empty and read-socket shutdown:
2075 * tell peer, that we will not send more data: send IEOF.
2076 * hack for extended data: delay EOF if EFD still in use.
2077 */
2078 if (CHANNEL_EFD_INPUT_ACTIVE(c))
2079 debug2("channel %d: ibuf_empty delayed efd %d/(%d)",
2080 c->self, c->efd, buffer_len(&c->extended));
2081 else
2082 chan_ibuf_empty(c);
2083 }
2084 /* Send extended data, i.e. stderr */
2085 if (compat20 &&
2086 !(c->flags & CHAN_EOF_SENT) &&
2087 c->remote_window > 0 &&
2088 (len = buffer_len(&c->extended)) > 0 &&
2089 c->extended_usage == CHAN_EXTENDED_READ) {
2090 debug2("channel %d: rwin %u elen %u euse %d",
2091 c->self, c->remote_window, buffer_len(&c->extended),
2092 c->extended_usage);
2093 if (len > c->remote_window)
2094 len = c->remote_window;
2095 if (len > c->remote_maxpacket)
2096 len = c->remote_maxpacket;
2097 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
2098 packet_put_int(c->remote_id);
2099 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
2100 packet_put_string(buffer_ptr(&c->extended), len);
2101 packet_length = packet_send();
2102 buffer_consume(&c->extended, len);
2103 c->remote_window -= len;
2104 debug2("channel %d: sent ext data %d", c->self, len);
2105 }
2106 }
2107 return (packet_length);
2108 }
2109
2110
2111 /* -- protocol input */
2112
2113 /* ARGSUSED */
2114 void
2115 channel_input_data(int type, u_int32_t seq, void *ctxt)
2116 {
2117 int id;
2118 char *data;
2119 u_int data_len;
2120 Channel *c;
2121
2122 /* Get the channel number and verify it. */
2123 id = packet_get_int();
2124 c = channel_lookup(id);
2125 if (c == NULL)
2126 packet_disconnect("Received data for nonexistent channel %d.", id);
2127
2128 /* Ignore any data for non-open channels (might happen on close) */
2129 if (c->type != SSH_CHANNEL_OPEN &&
2130 c->type != SSH_CHANNEL_X11_OPEN)
2131 return;
2132
2133 /* Get the data. */
2134 data = packet_get_string_ptr(&data_len);
2135
2136 /*
2137 * Ignore data for protocol > 1.3 if output end is no longer open.
2138 * For protocol 2 the sending side is reducing its window as it sends
2139 * data, so we must 'fake' consumption of the data in order to ensure
2140 * that window updates are sent back. Otherwise the connection might
2141 * deadlock.
2142 */
2143 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) {
2144 if (compat20) {
2145 c->local_window -= data_len;
2146 c->local_consumed += data_len;
2147 }
2148 return;
2149 }
2150
2151 if (compat20) {
2152 if (data_len > c->local_maxpacket) {
2153 logit("channel %d: rcvd big packet %d, maxpack %d",
2154 c->self, data_len, c->local_maxpacket);
2155 }
2156 if (data_len > c->local_window) {
2157 logit("channel %d: rcvd too much data %d, win %d",
2158 c->self, data_len, c->local_window);
2159 return;
2160 }
2161 c->local_window -= data_len;
2162 }
2163 if (c->datagram)
2164 buffer_put_string(&c->output, data, data_len);
2165 else
2166 buffer_append(&c->output, data, data_len);
2167 packet_check_eom();
2168 }
2169
2170 /* ARGSUSED */
2171 void
2172 channel_input_extended_data(int type, u_int32_t seq, void *ctxt)
2173 {
2174 int id;
2175 char *data;
2176 u_int data_len, tcode;
2177 Channel *c;
2178
2179 /* Get the channel number and verify it. */
2180 id = packet_get_int();
2181 c = channel_lookup(id);
2182
2183 if (c == NULL)
2184 packet_disconnect("Received extended_data for bad channel %d.", id);
2185 if (c->type != SSH_CHANNEL_OPEN) {
2186 logit("channel %d: ext data for non open", id);
2187 return;
2188 }
2189 if (c->flags & CHAN_EOF_RCVD) {
2190 if (datafellows & SSH_BUG_EXTEOF)
2191 debug("channel %d: accepting ext data after eof", id);
2192 else
2193 packet_disconnect("Received extended_data after EOF "
2194 "on channel %d.", id);
2195 }
2196 tcode = packet_get_int();
2197 if (c->efd == -1 ||
2198 c->extended_usage != CHAN_EXTENDED_WRITE ||
2199 tcode != SSH2_EXTENDED_DATA_STDERR) {
2200 logit("channel %d: bad ext data", c->self);
2201 return;
2202 }
2203 data = packet_get_string(&data_len);
2204 packet_check_eom();
2205 if (data_len > c->local_window) {
2206 logit("channel %d: rcvd too much extended_data %d, win %d",
2207 c->self, data_len, c->local_window);
2208 xfree(data);
2209 return;
2210 }
2211 debug2("channel %d: rcvd ext data %d", c->self, data_len);
2212 c->local_window -= data_len;
2213 buffer_append(&c->extended, data, data_len);
2214 xfree(data);
2215 }
2216
2217 /* ARGSUSED */
2218 void
2219 channel_input_ieof(int type, u_int32_t seq, void *ctxt)
2220 {
2221 int id;
2222 Channel *c;
2223
2224 id = packet_get_int();
2225 packet_check_eom();
2226 c = channel_lookup(id);
2227 if (c == NULL)
2228 packet_disconnect("Received ieof for nonexistent channel %d.", id);
2229 chan_rcvd_ieof(c);
2230
2231 /* XXX force input close */
2232 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) {
2233 debug("channel %d: FORCE input drain", c->self);
2234 c->istate = CHAN_INPUT_WAIT_DRAIN;
2235 if (buffer_len(&c->input) == 0)
2236 chan_ibuf_empty(c);
2237 }
2238
2239 }
2240
2241 /* ARGSUSED */
2242 void
2243 channel_input_close(int type, u_int32_t seq, void *ctxt)
2244 {
2245 int id;
2246 Channel *c;
2247
2248 id = packet_get_int();
2249 packet_check_eom();
2250 c = channel_lookup(id);
2251 if (c == NULL)
2252 packet_disconnect("Received close for nonexistent channel %d.", id);
2253
2254 /*
2255 * Send a confirmation that we have closed the channel and no more
2256 * data is coming for it.
2257 */
2258 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
2259 packet_put_int(c->remote_id);
2260 packet_send();
2261
2262 /*
2263 * If the channel is in closed state, we have sent a close request,
2264 * and the other side will eventually respond with a confirmation.
2265 * Thus, we cannot free the channel here, because then there would be
2266 * no-one to receive the confirmation. The channel gets freed when
2267 * the confirmation arrives.
2268 */
2269 if (c->type != SSH_CHANNEL_CLOSED) {
2270 /*
2271 * Not a closed channel - mark it as draining, which will
2272 * cause it to be freed later.
2273 */
2274 buffer_clear(&c->input);
2275 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
2276 }
2277 }
2278
2279 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
2280 /* ARGSUSED */
2281 void
2282 channel_input_oclose(int type, u_int32_t seq, void *ctxt)
2283 {
2284 int id = packet_get_int();
2285 Channel *c = channel_lookup(id);
2286
2287 packet_check_eom();
2288 if (c == NULL)
2289 packet_disconnect("Received oclose for nonexistent channel %d.", id);
2290 chan_rcvd_oclose(c);
2291 }
2292
2293 /* ARGSUSED */
2294 void
2295 channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt)
2296 {
2297 int id = packet_get_int();
2298 Channel *c = channel_lookup(id);
2299
2300 packet_check_eom();
2301 if (c == NULL)
2302 packet_disconnect("Received close confirmation for "
2303 "out-of-range channel %d.", id);
2304 if (c->type != SSH_CHANNEL_CLOSED)
2305 packet_disconnect("Received close confirmation for "
2306 "non-closed channel %d (type %d).", id, c->type);
2307 channel_free(c);
2308 }
2309
2310 /* ARGSUSED */
2311 void
2312 channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt)
2313 {
2314 int id, remote_id;
2315 Channel *c;
2316
2317 id = packet_get_int();
2318 c = channel_lookup(id);
2319
2320 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2321 packet_disconnect("Received open confirmation for "
2322 "non-opening channel %d.", id);
2323 remote_id = packet_get_int();
2324 /* Record the remote channel number and mark that the channel is now open. */
2325 c->remote_id = remote_id;
2326 c->type = SSH_CHANNEL_OPEN;
2327
2328 if (compat20) {
2329 c->remote_window = packet_get_int();
2330 c->remote_maxpacket = packet_get_int();
2331 if (c->open_confirm) {
2332 debug2("callback start");
2333 c->open_confirm(c->self, c->open_confirm_ctx);
2334 debug2("callback done");
2335 }
2336 debug2("channel %d: open confirm rwindow %u rmax %u", c->self,
2337 c->remote_window, c->remote_maxpacket);
2338 }
2339 packet_check_eom();
2340 }
2341
2342 static char *
2343 reason2txt(int reason)
2344 {
2345 switch (reason) {
2346 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
2347 return "administratively prohibited";
2348 case SSH2_OPEN_CONNECT_FAILED:
2349 return "connect failed";
2350 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
2351 return "unknown channel type";
2352 case SSH2_OPEN_RESOURCE_SHORTAGE:
2353 return "resource shortage";
2354 }
2355 return "unknown reason";
2356 }
2357
2358 /* ARGSUSED */
2359 void
2360 channel_input_open_failure(int type, u_int32_t seq, void *ctxt)
2361 {
2362 int id, reason;
2363 char *msg = NULL, *lang = NULL;
2364 Channel *c;
2365
2366 id = packet_get_int();
2367 c = channel_lookup(id);
2368
2369 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2370 packet_disconnect("Received open failure for "
2371 "non-opening channel %d.", id);
2372 if (compat20) {
2373 reason = packet_get_int();
2374 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
2375 msg = packet_get_string(NULL);
2376 lang = packet_get_string(NULL);
2377 }
2378 logit("channel %d: open failed: %s%s%s", id,
2379 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
2380 if (msg != NULL)
2381 xfree(msg);
2382 if (lang != NULL)
2383 xfree(lang);
2384 }
2385 packet_check_eom();
2386 /* Schedule the channel for cleanup/deletion. */
2387 chan_mark_dead(c);
2388 }
2389
2390 /* ARGSUSED */
2391 void
2392 channel_input_window_adjust(int type, u_int32_t seq, void *ctxt)
2393 {
2394 Channel *c;
2395 int id;
2396 u_int adjust;
2397
2398 if (!compat20)
2399 return;
2400
2401 /* Get the channel number and verify it. */
2402 id = packet_get_int();
2403 c = channel_lookup(id);
2404
2405 if (c == NULL) {
2406 logit("Received window adjust for non-open channel %d.", id);
2407 return;
2408 }
2409 adjust = packet_get_int();
2410 packet_check_eom();
2411 debug2("channel %d: rcvd adjust %u", id, adjust);
2412 c->remote_window += adjust;
2413 }
2414
2415 /* ARGSUSED */
2416 void
2417 channel_input_port_open(int type, u_int32_t seq, void *ctxt)
2418 {
2419 Channel *c = NULL;
2420 u_short host_port;
2421 char *host, *originator_string;
2422 int remote_id;
2423
2424 remote_id = packet_get_int();
2425 host = packet_get_string(NULL);
2426 host_port = packet_get_int();
2427
2428 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2429 originator_string = packet_get_string(NULL);
2430 } else {
2431 originator_string = xstrdup("unknown (remote did not supply name)");
2432 }
2433 packet_check_eom();
2434 c = channel_connect_to(host, host_port,
2435 "connected socket", originator_string);
2436 xfree(originator_string);
2437 xfree(host);
2438 if (c == NULL) {
2439 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2440 packet_put_int(remote_id);
2441 packet_send();
2442 } else
2443 c->remote_id = remote_id;
2444 }
2445
2446 /* ARGSUSED */
2447 void
2448 channel_input_status_confirm(int type, u_int32_t seq, void *ctxt)
2449 {
2450 Channel *c;
2451 struct channel_confirm *cc;
2452 int id;
2453
2454 /* Reset keepalive timeout */
2455 packet_set_alive_timeouts(0);
2456
2457 id = packet_get_int();
2458 packet_check_eom();
2459
2460 debug2("channel_input_status_confirm: type %d id %d", type, id);
2461
2462 if ((c = channel_lookup(id)) == NULL) {
2463 logit("channel_input_status_confirm: %d: unknown", id);
2464 return;
2465 }
2466 ;
2467 if ((cc = TAILQ_FIRST(&c->status_confirms)) == NULL)
2468 return;
2469 cc->cb(type, c, cc->ctx);
2470 TAILQ_REMOVE(&c->status_confirms, cc, entry);
2471 bzero(cc, sizeof(*cc));
2472 xfree(cc);
2473 }
2474
2475 /* -- tcp forwarding */
2476
2477 void
2478 channel_set_af(int af)
2479 {
2480 IPv4or6 = af;
2481 }
2482
2483
2484 void
2485 channel_set_hpn(int external_hpn_disabled, int external_hpn_buffer_size)
2486 {
2487 hpn_disabled = external_hpn_disabled;
2488 hpn_buffer_size = external_hpn_buffer_size;
2489 debug("HPN Disabled: %d, HPN Buffer Size: %d", hpn_disabled, hpn_buffer_size);
2490 }
2491
2492 static int
2493 channel_setup_fwd_listener(int type, const char *listen_addr,
2494 u_short listen_port, int *allocated_listen_port,
2495 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2496 {
2497 Channel *c;
2498 int sock, r, success = 0, wildcard = 0, is_client;
2499 struct addrinfo hints, *ai, *aitop;
2500 const char *host, *addr;
2501 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2502 in_port_t *lport_p;
2503
2504 host = (type == SSH_CHANNEL_RPORT_LISTENER) ?
2505 listen_addr : host_to_connect;
2506 is_client = (type == SSH_CHANNEL_PORT_LISTENER);
2507
2508 if (host == NULL) {
2509 error("No forward host name.");
2510 return 0;
2511 }
2512 if (strlen(host) >= NI_MAXHOST) {
2513 error("Forward host name too long.");
2514 return 0;
2515 }
2516
2517 /*
2518 * Determine whether or not a port forward listens to loopback,
2519 * specified address or wildcard. On the client, a specified bind
2520 * address will always override gateway_ports. On the server, a
2521 * gateway_ports of 1 (``yes'') will override the client's
2522 * specification and force a wildcard bind, whereas a value of 2
2523 * (``clientspecified'') will bind to whatever address the client
2524 * asked for.
2525 *
2526 * Special-case listen_addrs are:
2527 *
2528 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR
2529 * "" (empty string), "*" -> wildcard v4/v6
2530 * "localhost" -> loopback v4/v6
2531 */
2532 addr = NULL;
2533 if (listen_addr == NULL) {
2534 /* No address specified: default to gateway_ports setting */
2535 if (gateway_ports)
2536 wildcard = 1;
2537 } else if (gateway_ports || is_client) {
2538 if (((datafellows & SSH_OLD_FORWARD_ADDR) &&
2539 strcmp(listen_addr, "0.0.0.0") == 0 && is_client == 0) ||
2540 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 ||
2541 (!is_client && gateway_ports == 1))
2542 wildcard = 1;
2543 else if (strcmp(listen_addr, "localhost") != 0)
2544 addr = listen_addr;
2545 }
2546
2547 debug3("channel_setup_fwd_listener: type %d wildcard %d addr %s",
2548 type, wildcard, (addr == NULL) ? "NULL" : addr);
2549
2550 /*
2551 * getaddrinfo returns a loopback address if the hostname is
2552 * set to NULL and hints.ai_flags is not AI_PASSIVE
2553 */
2554 memset(&hints, 0, sizeof(hints));
2555 hints.ai_family = IPv4or6;
2556 hints.ai_flags = wildcard ? AI_PASSIVE : 0;
2557 hints.ai_socktype = SOCK_STREAM;
2558 snprintf(strport, sizeof strport, "%d", listen_port);
2559 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) {
2560 if (addr == NULL) {
2561 /* This really shouldn't happen */
2562 packet_disconnect("getaddrinfo: fatal error: %s",
2563 ssh_gai_strerror(r));
2564 } else {
2565 error("channel_setup_fwd_listener: "
2566 "getaddrinfo(%.64s): %s", addr,
2567 ssh_gai_strerror(r));
2568 }
2569 return 0;
2570 }
2571 if (allocated_listen_port != NULL)
2572 *allocated_listen_port = 0;
2573 for (ai = aitop; ai; ai = ai->ai_next) {
2574 switch (ai->ai_family) {
2575 case AF_INET:
2576 lport_p = &((struct sockaddr_in *)ai->ai_addr)->
2577 sin_port;
2578 break;
2579 case AF_INET6:
2580 lport_p = &((struct sockaddr_in6 *)ai->ai_addr)->
2581 sin6_port;
2582 break;
2583 default:
2584 continue;
2585 }
2586 /*
2587 * If allocating a port for -R forwards, then use the
2588 * same port for all address families.
2589 */
2590 if (type == SSH_CHANNEL_RPORT_LISTENER && listen_port == 0 &&
2591 allocated_listen_port != NULL && *allocated_listen_port > 0)
2592 *lport_p = htons(*allocated_listen_port);
2593
2594 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2595 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2596 error("channel_setup_fwd_listener: getnameinfo failed");
2597 continue;
2598 }
2599 /* Create a port to listen for the host. */
2600 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2601 if (sock < 0) {
2602 /* this is no error since kernel may not support ipv6 */
2603 verbose("socket: %.100s", strerror(errno));
2604 continue;
2605 }
2606
2607 channel_set_reuseaddr(sock);
2608
2609 debug("Local forwarding listening on %s port %s.",
2610 ntop, strport);
2611
2612 /* Bind the socket to the address. */
2613 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2614 /* address can be in use ipv6 address is already bound */
2615 verbose("bind: %.100s", strerror(errno));
2616 close(sock);
2617 continue;
2618 }
2619 /* Start listening for connections on the socket. */
2620 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2621 error("listen: %.100s", strerror(errno));
2622 close(sock);
2623 continue;
2624 }
2625
2626 /*
2627 * listen_port == 0 requests a dynamically allocated port -
2628 * record what we got.
2629 */
2630 if (type == SSH_CHANNEL_RPORT_LISTENER && listen_port == 0 &&
2631 allocated_listen_port != NULL &&
2632 *allocated_listen_port == 0) {
2633 *allocated_listen_port = get_sock_port(sock, 1);
2634 debug("Allocated listen port %d",
2635 *allocated_listen_port);
2636 }
2637
2638 /* Allocate a channel number for the socket. */
2639 /* explicitly test for hpn disabled option. if true use smaller window size */
2640 if (hpn_disabled)
2641 c = channel_new("port listener", type, sock, sock, -1,
2642 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2643 0, "port listener", 1);
2644 else
2645 c = channel_new("port listener", type, sock, sock, -1,
2646 hpn_buffer_size, CHAN_TCP_PACKET_DEFAULT,
2647 0, "port listener", 1);
2648 c->path = xstrdup(host);
2649 c->host_port = port_to_connect;
2650 c->listening_port = listen_port;
2651 success = 1;
2652 }
2653 if (success == 0)
2654 error("channel_setup_fwd_listener: cannot listen to port: %d",
2655 listen_port);
2656 freeaddrinfo(aitop);
2657 return success;
2658 }
2659
2660 int
2661 channel_cancel_rport_listener(const char *host, u_short port)
2662 {
2663 u_int i;
2664 int found = 0;
2665
2666 for (i = 0; i < channels_alloc; i++) {
2667 Channel *c = channels[i];
2668
2669 if (c != NULL && c->type == SSH_CHANNEL_RPORT_LISTENER &&
2670 strcmp(c->path, host) == 0 && c->listening_port == port) {
2671 debug2("%s: close channel %d", __func__, i);
2672 channel_free(c);
2673 found = 1;
2674 }
2675 }
2676
2677 return (found);
2678 }
2679
2680 /* protocol local port fwd, used by ssh (and sshd in v1) */
2681 int
2682 channel_setup_local_fwd_listener(const char *listen_host, u_short listen_port,
2683 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2684 {
2685 return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER,
2686 listen_host, listen_port, NULL, host_to_connect, port_to_connect,
2687 gateway_ports);
2688 }
2689
2690 /* protocol v2 remote port fwd, used by sshd */
2691 int
2692 channel_setup_remote_fwd_listener(const char *listen_address,
2693 u_short listen_port, int *allocated_listen_port, int gateway_ports)
2694 {
2695 return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER,
2696 listen_address, listen_port, allocated_listen_port,
2697 NULL, 0, gateway_ports);
2698 }
2699
2700 /*
2701 * Initiate forwarding of connections to port "port" on remote host through
2702 * the secure channel to host:port from local side.
2703 */
2704
2705 int
2706 channel_request_remote_forwarding(const char *listen_host, u_short listen_port,
2707 const char *host_to_connect, u_short port_to_connect)
2708 {
2709 int type, success = 0;
2710
2711 /* Record locally that connection to this host/port is permitted. */
2712 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2713 fatal("channel_request_remote_forwarding: too many forwards");
2714
2715 /* Send the forward request to the remote side. */
2716 if (compat20) {
2717 const char *address_to_bind;
2718 if (listen_host == NULL) {
2719 if (datafellows & SSH_BUG_RFWD_ADDR)
2720 address_to_bind = "127.0.0.1";
2721 else
2722 address_to_bind = "localhost";
2723 } else if (*listen_host == '\0' ||
2724 strcmp(listen_host, "*") == 0) {
2725 if (datafellows & SSH_BUG_RFWD_ADDR)
2726 address_to_bind = "0.0.0.0";
2727 else
2728 address_to_bind = "";
2729 } else
2730 address_to_bind = listen_host;
2731
2732 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2733 packet_put_cstring("tcpip-forward");
2734 packet_put_char(1); /* boolean: want reply */
2735 packet_put_cstring(address_to_bind);
2736 packet_put_int(listen_port);
2737 packet_send();
2738 packet_write_wait();
2739 /* Assume that server accepts the request */
2740 success = 1;
2741 } else {
2742 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2743 packet_put_int(listen_port);
2744 packet_put_cstring(host_to_connect);
2745 packet_put_int(port_to_connect);
2746 packet_send();
2747 packet_write_wait();
2748
2749 /* Wait for response from the remote side. */
2750 type = packet_read();
2751 switch (type) {
2752 case SSH_SMSG_SUCCESS:
2753 success = 1;
2754 break;
2755 case SSH_SMSG_FAILURE:
2756 break;
2757 default:
2758 /* Unknown packet */
2759 packet_disconnect("Protocol error for port forward request:"
2760 "received packet type %d.", type);
2761 }
2762 }
2763 if (success) {
2764 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2765 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2766 permitted_opens[num_permitted_opens].listen_port = listen_port;
2767 num_permitted_opens++;
2768 }
2769 return (success ? 0 : -1);
2770 }
2771
2772 /*
2773 * Request cancellation of remote forwarding of connection host:port from
2774 * local side.
2775 */
2776 void
2777 channel_request_rforward_cancel(const char *host, u_short port)
2778 {
2779 int i;
2780
2781 if (!compat20)
2782 return;
2783
2784 for (i = 0; i < num_permitted_opens; i++) {
2785 if (permitted_opens[i].host_to_connect != NULL &&
2786 permitted_opens[i].listen_port == port)
2787 break;
2788 }
2789 if (i >= num_permitted_opens) {
2790 debug("%s: requested forward not found", __func__);
2791 return;
2792 }
2793 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2794 packet_put_cstring("cancel-tcpip-forward");
2795 packet_put_char(0);
2796 packet_put_cstring(host == NULL ? "" : host);
2797 packet_put_int(port);
2798 packet_send();
2799
2800 permitted_opens[i].listen_port = 0;
2801 permitted_opens[i].port_to_connect = 0;
2802 xfree(permitted_opens[i].host_to_connect);
2803 permitted_opens[i].host_to_connect = NULL;
2804 }
2805
2806 /*
2807 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
2808 * listening for the port, and sends back a success reply (or disconnect
2809 * message if there was an error).
2810 */
2811 int
2812 channel_input_port_forward_request(int is_root, int gateway_ports)
2813 {
2814 u_short port, host_port;
2815 int success = 0;
2816 char *hostname;
2817
2818 /* Get arguments from the packet. */
2819 port = packet_get_int();
2820 hostname = packet_get_string(NULL);
2821 host_port = packet_get_int();
2822
2823 /*
2824 * Check that an unprivileged user is not trying to forward a
2825 * privileged port.
2826 */
2827 if (port < IPPORT_RESERVED && !is_root)
2828 packet_disconnect(
2829 "Requested forwarding of port %d but user is not root.",
2830 port);
2831 if (host_port == 0)
2832 packet_disconnect("Dynamic forwarding denied.");
2833
2834 /* Initiate forwarding */
2835 success = channel_setup_local_fwd_listener(NULL, port, hostname,
2836 host_port, gateway_ports);
2837
2838 /* Free the argument string. */
2839 xfree(hostname);
2840
2841 return (success ? 0 : -1);
2842 }
2843
2844 /*
2845 * Permits opening to any host/port if permitted_opens[] is empty. This is
2846 * usually called by the server, because the user could connect to any port
2847 * anyway, and the server has no way to know but to trust the client anyway.
2848 */
2849 void
2850 channel_permit_all_opens(void)
2851 {
2852 if (num_permitted_opens == 0)
2853 all_opens_permitted = 1;
2854 }
2855
2856 void
2857 channel_add_permitted_opens(char *host, int port)
2858 {
2859 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2860 fatal("channel_add_permitted_opens: too many forwards");
2861 debug("allow port forwarding to host %s port %d", host, port);
2862
2863 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
2864 permitted_opens[num_permitted_opens].port_to_connect = port;
2865 num_permitted_opens++;
2866
2867 all_opens_permitted = 0;
2868 }
2869
2870 int
2871 channel_add_adm_permitted_opens(char *host, int port)
2872 {
2873 if (num_adm_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2874 fatal("channel_add_adm_permitted_opens: too many forwards");
2875 debug("config allows port forwarding to host %s port %d", host, port);
2876
2877 permitted_adm_opens[num_adm_permitted_opens].host_to_connect
2878 = xstrdup(host);
2879 permitted_adm_opens[num_adm_permitted_opens].port_to_connect = port;
2880 return ++num_adm_permitted_opens;
2881 }
2882
2883 void
2884 channel_clear_permitted_opens(void)
2885 {
2886 int i;
2887
2888 for (i = 0; i < num_permitted_opens; i++)
2889 if (permitted_opens[i].host_to_connect != NULL)
2890 xfree(permitted_opens[i].host_to_connect);
2891 num_permitted_opens = 0;
2892 }
2893
2894 void
2895 channel_clear_adm_permitted_opens(void)
2896 {
2897 int i;
2898
2899 for (i = 0; i < num_adm_permitted_opens; i++)
2900 if (permitted_adm_opens[i].host_to_connect != NULL)
2901 xfree(permitted_adm_opens[i].host_to_connect);
2902 num_adm_permitted_opens = 0;
2903 }
2904
2905 void
2906 channel_print_adm_permitted_opens(void)
2907 {
2908 int i;
2909
2910 printf("permitopen");
2911 if (num_adm_permitted_opens == 0) {
2912 printf(" any\n");
2913 return;
2914 }
2915 for (i = 0; i < num_adm_permitted_opens; i++)
2916 if (permitted_adm_opens[i].host_to_connect != NULL)
2917 printf(" %s:%d", permitted_adm_opens[i].host_to_connect,
2918 permitted_adm_opens[i].port_to_connect);
2919 printf("\n");
2920 }
2921
2922 /* Try to start non-blocking connect to next host in cctx list */
2923 static int
2924 connect_next(struct channel_connect *cctx)
2925 {
2926 int sock, saved_errno;
2927 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2928
2929 for (; cctx->ai; cctx->ai = cctx->ai->ai_next) {
2930 if (cctx->ai->ai_family != AF_INET &&
2931 cctx->ai->ai_family != AF_INET6)
2932 continue;
2933 if (getnameinfo(cctx->ai->ai_addr, cctx->ai->ai_addrlen,
2934 ntop, sizeof(ntop), strport, sizeof(strport),
2935 NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2936 error("connect_next: getnameinfo failed");
2937 continue;
2938 }
2939 if ((sock = socket(cctx->ai->ai_family, cctx->ai->ai_socktype,
2940 cctx->ai->ai_protocol)) == -1) {
2941 if (cctx->ai->ai_next == NULL)
2942 error("socket: %.100s", strerror(errno));
2943 else
2944 verbose("socket: %.100s", strerror(errno));
2945 continue;
2946 }
2947 if (set_nonblock(sock) == -1)
2948 fatal("%s: set_nonblock(%d)", __func__, sock);
2949 if (connect(sock, cctx->ai->ai_addr,
2950 cctx->ai->ai_addrlen) == -1 && errno != EINPROGRESS) {
2951 debug("connect_next: host %.100s ([%.100s]:%s): "
2952 "%.100s", cctx->host, ntop, strport,
2953 strerror(errno));
2954 saved_errno = errno;
2955 close(sock);
2956 errno = saved_errno;
2957 continue; /* fail -- try next */
2958 }
2959 debug("connect_next: host %.100s ([%.100s]:%s) "
2960 "in progress, fd=%d", cctx->host, ntop, strport, sock);
2961 cctx->ai = cctx->ai->ai_next;
2962 set_nodelay(sock);
2963 return sock;
2964 }
2965 return -1;
2966 }
2967
2968 static void
2969 channel_connect_ctx_free(struct channel_connect *cctx)
2970 {
2971 xfree(cctx->host);
2972 if (cctx->aitop)
2973 freeaddrinfo(cctx->aitop);
2974 bzero(cctx, sizeof(*cctx));
2975 cctx->host = NULL;
2976 cctx->ai = cctx->aitop = NULL;
2977 }
2978
2979 /* Return CONNECTING channel to remote host, port */
2980 static Channel *
2981 connect_to(const char *host, u_short port, char *ctype, char *rname)
2982 {
2983 struct addrinfo hints;
2984 int gaierr;
2985 int sock = -1;
2986 char strport[NI_MAXSERV];
2987 struct channel_connect cctx;
2988 Channel *c;
2989
2990 memset(&cctx, 0, sizeof(cctx));
2991 memset(&hints, 0, sizeof(hints));
2992 hints.ai_family = IPv4or6;
2993 hints.ai_socktype = SOCK_STREAM;
2994 snprintf(strport, sizeof strport, "%d", port);
2995 if ((gaierr = getaddrinfo(host, strport, &hints, &cctx.aitop)) != 0) {
2996 error("connect_to %.100s: unknown host (%s)", host,
2997 ssh_gai_strerror(gaierr));
2998 return NULL;
2999 }
3000
3001 cctx.host = xstrdup(host);
3002 cctx.port = port;
3003 cctx.ai = cctx.aitop;
3004
3005 if ((sock = connect_next(&cctx)) == -1) {
3006 error("connect to %.100s port %d failed: %s",
3007 host, port, strerror(errno));
3008 channel_connect_ctx_free(&cctx);
3009 return NULL;
3010 }
3011 c = channel_new(ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1,
3012 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1);
3013 c->connect_ctx = cctx;
3014 return c;
3015 }
3016
3017 Channel *
3018 channel_connect_by_listen_address(u_short listen_port, char *ctype, char *rname)
3019 {
3020 int i;
3021
3022 for (i = 0; i < num_permitted_opens; i++) {
3023 if (permitted_opens[i].host_to_connect != NULL &&
3024 permitted_opens[i].listen_port == listen_port) {
3025 return connect_to(
3026 permitted_opens[i].host_to_connect,
3027 permitted_opens[i].port_to_connect, ctype, rname);
3028 }
3029 }
3030 error("WARNING: Server requests forwarding for unknown listen_port %d",
3031 listen_port);
3032 return NULL;
3033 }
3034
3035 /* Check if connecting to that port is permitted and connect. */
3036 Channel *
3037 channel_connect_to(const char *host, u_short port, char *ctype, char *rname)
3038 {
3039 int i, permit, permit_adm = 1;
3040
3041 permit = all_opens_permitted;
3042 if (!permit) {
3043 for (i = 0; i < num_permitted_opens; i++)
3044 if (permitted_opens[i].host_to_connect != NULL &&
3045 permitted_opens[i].port_to_connect == port &&
3046 strcmp(permitted_opens[i].host_to_connect, host) == 0)
3047 permit = 1;
3048 }
3049
3050 if (num_adm_permitted_opens > 0) {
3051 permit_adm = 0;
3052 for (i = 0; i < num_adm_permitted_opens; i++)
3053 if (permitted_adm_opens[i].host_to_connect != NULL &&
3054 permitted_adm_opens[i].port_to_connect == port &&
3055 strcmp(permitted_adm_opens[i].host_to_connect, host)
3056 == 0)
3057 permit_adm = 1;
3058 }
3059
3060 if (!permit || !permit_adm) {
3061 logit("Received request to connect to host %.100s port %d, "
3062 "but the request was denied.", host, port);
3063 return NULL;
3064 }
3065 return connect_to(host, port, ctype, rname);
3066 }
3067
3068 void
3069 channel_send_window_changes(void)
3070 {
3071 u_int i;
3072 struct winsize ws;
3073
3074 for (i = 0; i < channels_alloc; i++) {
3075 if (channels[i] == NULL || !channels[i]->client_tty ||
3076 channels[i]->type != SSH_CHANNEL_OPEN)
3077 continue;
3078 if (ioctl(channels[i]->rfd, TIOCGWINSZ, &ws) < 0)
3079 continue;
3080 channel_request_start(i, "window-change", 0);
3081 packet_put_int((u_int)ws.ws_col);
3082 packet_put_int((u_int)ws.ws_row);
3083 packet_put_int((u_int)ws.ws_xpixel);
3084 packet_put_int((u_int)ws.ws_ypixel);
3085 packet_send();
3086 }
3087 }
3088
3089 /* -- X11 forwarding */
3090
3091 /*
3092 * Creates an internet domain socket for listening for X11 connections.
3093 * Returns 0 and a suitable display number for the DISPLAY variable
3094 * stored in display_numberp , or -1 if an error occurs.
3095 */
3096 int
3097 x11_create_display_inet(int x11_display_offset, int x11_use_localhost,
3098 int single_connection, u_int *display_numberp, int **chanids)
3099 {
3100 Channel *nc = NULL;
3101 int display_number, sock;
3102 u_short port;
3103 struct addrinfo hints, *ai, *aitop;
3104 char strport[NI_MAXSERV];
3105 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
3106
3107 if (chanids == NULL)
3108 return -1;
3109
3110 for (display_number = x11_display_offset;
3111 display_number < MAX_DISPLAYS;
3112 display_number++) {
3113 port = 6000 + display_number;
3114 memset(&hints, 0, sizeof(hints));
3115 hints.ai_family = IPv4or6;
3116 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE;
3117 hints.ai_socktype = SOCK_STREAM;
3118 snprintf(strport, sizeof strport, "%d", port);
3119 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
3120 error("getaddrinfo: %.100s", ssh_gai_strerror(gaierr));
3121 return -1;
3122 }
3123 for (ai = aitop; ai; ai = ai->ai_next) {
3124 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
3125 continue;
3126 sock = socket(ai->ai_family, ai->ai_socktype,
3127 ai->ai_protocol);
3128 if (sock < 0) {
3129 error("socket: %.100s", strerror(errno));
3130 freeaddrinfo(aitop);
3131 return -1;
3132 }
3133 channel_set_reuseaddr(sock);
3134 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
3135 debug2("bind port %d: %.100s", port, strerror(errno));
3136 close(sock);
3137
3138 for (n = 0; n < num_socks; n++) {
3139 close(socks[n]);
3140 }
3141 num_socks = 0;
3142 break;
3143 }
3144 socks[num_socks++] = sock;
3145 if (num_socks == NUM_SOCKS)
3146 break;
3147 }
3148 freeaddrinfo(aitop);
3149 if (num_socks > 0)
3150 break;
3151 }
3152 if (display_number >= MAX_DISPLAYS) {
3153 error("Failed to allocate internet-domain X11 display socket.");
3154 return -1;
3155 }
3156 /* Start listening for connections on the socket. */
3157 for (n = 0; n < num_socks; n++) {
3158 sock = socks[n];
3159 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
3160 error("listen: %.100s", strerror(errno));
3161 close(sock);
3162 return -1;
3163 }
3164 }
3165
3166 /* Allocate a channel for each socket. */
3167 *chanids = xcalloc(num_socks + 1, sizeof(**chanids));
3168 for (n = 0; n < num_socks; n++) {
3169 sock = socks[n];
3170 /* Is this really necassary? */
3171 if (hpn_disabled)
3172 nc = channel_new("x11 listener",
3173 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
3174 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
3175 0, "X11 inet listener", 1);
3176 else
3177 nc = channel_new("x11 listener",
3178 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
3179 hpn_buffer_size, CHAN_X11_PACKET_DEFAULT,
3180 0, "X11 inet listener", 1);
3181 nc->single_connection = single_connection;
3182 (*chanids)[n] = nc->self;
3183 }
3184 (*chanids)[n] = -1;
3185
3186 /* Return the display number for the DISPLAY environment variable. */
3187 *display_numberp = display_number;
3188 return (0);
3189 }
3190
3191 static int
3192 connect_local_xsocket(u_int dnr)
3193 {
3194 int sock;
3195 struct sockaddr_un addr;
3196
3197 sock = socket(AF_UNIX, SOCK_STREAM, 0);
3198 if (sock < 0)
3199 error("socket: %.100s", strerror(errno));
3200 memset(&addr, 0, sizeof(addr));
3201 addr.sun_family = AF_UNIX;
3202 snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr);
3203 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0)
3204 return sock;
3205 close(sock);
3206 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
3207 return -1;
3208 }
3209
3210 int
3211 x11_connect_display(void)
3212 {
3213 u_int display_number;
3214 const char *display;
3215 char buf[1024], *cp;
3216 struct addrinfo hints, *ai, *aitop;
3217 char strport[NI_MAXSERV];
3218 int gaierr, sock = 0;
3219
3220 /* Try to open a socket for the local X server. */
3221 display = getenv("DISPLAY");
3222 if (!display) {
3223 error("DISPLAY not set.");
3224 return -1;
3225 }
3226 /*
3227 * Now we decode the value of the DISPLAY variable and make a
3228 * connection to the real X server.
3229 */
3230
3231 /*
3232 * Check if it is a unix domain socket. Unix domain displays are in
3233 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
3234 */
3235 if (strncmp(display, "unix:", 5) == 0 ||
3236 display[0] == ':') {
3237 /* Connect to the unix domain socket. */
3238 if (sscanf(strrchr(display, ':') + 1, "%u", &display_number) != 1) {
3239 error("Could not parse display number from DISPLAY: %.100s",
3240 display);
3241 return -1;
3242 }
3243 /* Create a socket. */
3244 sock = connect_local_xsocket(display_number);
3245 if (sock < 0)
3246 return -1;
3247
3248 /* OK, we now have a connection to the display. */
3249 return sock;
3250 }
3251 /*
3252 * Connect to an inet socket. The DISPLAY value is supposedly
3253 * hostname:d[.s], where hostname may also be numeric IP address.
3254 */
3255 strlcpy(buf, display, sizeof(buf));
3256 cp = strchr(buf, ':');
3257 if (!cp) {
3258 error("Could not find ':' in DISPLAY: %.100s", display);
3259 return -1;
3260 }
3261 *cp = 0;
3262 /* buf now contains the host name. But first we parse the display number. */
3263 if (sscanf(cp + 1, "%u", &display_number) != 1) {
3264 error("Could not parse display number from DISPLAY: %.100s",
3265 display);
3266 return -1;
3267 }
3268
3269 /* Look up the host address */
3270 memset(&hints, 0, sizeof(hints));
3271 hints.ai_family = IPv4or6;
3272 hints.ai_socktype = SOCK_STREAM;
3273 snprintf(strport, sizeof strport, "%u", 6000 + display_number);
3274 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
3275 error("%.100s: unknown host. (%s)", buf,
3276 ssh_gai_strerror(gaierr));
3277 return -1;
3278 }
3279 for (ai = aitop; ai; ai = ai->ai_next) {
3280 /* Create a socket. */
3281 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
3282 if (sock < 0) {
3283 debug2("socket: %.100s", strerror(errno));
3284 continue;
3285 }
3286 /* Connect it to the display. */
3287 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
3288 debug2("connect %.100s port %u: %.100s", buf,
3289 6000 + display_number, strerror(errno));
3290 close(sock);
3291 continue;
3292 }
3293 /* Success */
3294 break;
3295 }
3296 freeaddrinfo(aitop);
3297 if (!ai) {
3298 error("connect %.100s port %u: %.100s", buf, 6000 + display_number,
3299 strerror(errno));
3300 return -1;
3301 }
3302 set_nodelay(sock);
3303 return sock;
3304 }
3305
3306 /*
3307 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
3308 * the remote channel number. We should do whatever we want, and respond
3309 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
3310 */
3311
3312 /* ARGSUSED */
3313 void
3314 x11_input_open(int type, u_int32_t seq, void *ctxt)
3315 {
3316 Channel *c = NULL;
3317 int remote_id, sock = 0;
3318 char *remote_host;
3319
3320 debug("Received X11 open request.");
3321
3322 remote_id = packet_get_int();
3323
3324 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
3325 remote_host = packet_get_string(NULL);
3326 } else {
3327 remote_host = xstrdup("unknown (remote did not supply name)");
3328 }
3329 packet_check_eom();
3330
3331 /* Obtain a connection to the real X display. */
3332 sock = x11_connect_display();
3333 if (sock != -1) {
3334 /* Allocate a channel for this connection. */
3335 c = channel_new("connected x11 socket",
3336 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
3337 remote_host, 1);
3338 c->remote_id = remote_id;
3339 c->force_drain = 1;
3340 }
3341 xfree(remote_host);
3342 if (c == NULL) {
3343 /* Send refusal to the remote host. */
3344 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3345 packet_put_int(remote_id);
3346 } else {
3347 /* Send a confirmation to the remote host. */
3348 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
3349 packet_put_int(remote_id);
3350 packet_put_int(c->self);
3351 }
3352 packet_send();
3353 }
3354
3355 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
3356 /* ARGSUSED */
3357 void
3358 deny_input_open(int type, u_int32_t seq, void *ctxt)
3359 {
3360 int rchan = packet_get_int();
3361
3362 switch (type) {
3363 case SSH_SMSG_AGENT_OPEN:
3364 error("Warning: ssh server tried agent forwarding.");
3365 break;
3366 case SSH_SMSG_X11_OPEN:
3367 error("Warning: ssh server tried X11 forwarding.");
3368 break;
3369 default:
3370 error("deny_input_open: type %d", type);
3371 break;
3372 }
3373 error("Warning: this is probably a break-in attempt by a malicious server.");
3374 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3375 packet_put_int(rchan);
3376 packet_send();
3377 }
3378
3379 /*
3380 * Requests forwarding of X11 connections, generates fake authentication
3381 * data, and enables authentication spoofing.
3382 * This should be called in the client only.
3383 */
3384 void
3385 x11_request_forwarding_with_spoofing(int client_session_id, const char *disp,
3386 const char *proto, const char *data)
3387 {
3388 u_int data_len = (u_int) strlen(data) / 2;
3389 u_int i, value;
3390 char *new_data;
3391 int screen_number;
3392 const char *cp;
3393 u_int32_t rnd = 0;
3394
3395 if (x11_saved_display == NULL)
3396 x11_saved_display = xstrdup(disp);
3397 else if (strcmp(disp, x11_saved_display) != 0) {
3398 error("x11_request_forwarding_with_spoofing: different "
3399 "$DISPLAY already forwarded");
3400 return;
3401 }
3402
3403 cp = strchr(disp, ':');
3404 if (cp)
3405 cp = strchr(cp, '.');
3406 if (cp)
3407 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL);
3408 else
3409 screen_number = 0;
3410
3411 if (x11_saved_proto == NULL) {
3412 /* Save protocol name. */
3413 x11_saved_proto = xstrdup(proto);
3414 /*
3415 * Extract real authentication data and generate fake data
3416 * of the same length.
3417 */
3418 x11_saved_data = xmalloc(data_len);
3419 x11_fake_data = xmalloc(data_len);
3420 for (i = 0; i < data_len; i++) {
3421 if (sscanf(data + 2 * i, "%2x", &value) != 1)
3422 fatal("x11_request_forwarding: bad "
3423 "authentication data: %.100s", data);
3424 if (i % 4 == 0)
3425 rnd = arc4random();
3426 x11_saved_data[i] = value;
3427 x11_fake_data[i] = rnd & 0xff;
3428 rnd >>= 8;
3429 }
3430 x11_saved_data_len = data_len;
3431 x11_fake_data_len = data_len;
3432 }
3433
3434 /* Convert the fake data into hex. */
3435 new_data = tohex(x11_fake_data, data_len);
3436
3437 /* Send the request packet. */
3438 if (compat20) {
3439 channel_request_start(client_session_id, "x11-req", 0);
3440 packet_put_char(0); /* XXX bool single connection */
3441 } else {
3442 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
3443 }
3444 packet_put_cstring(proto);
3445 packet_put_cstring(new_data);
3446 packet_put_int(screen_number);
3447 packet_send();
3448 packet_write_wait();
3449 xfree(new_data);
3450 }
3451
3452
3453 /* -- agent forwarding */
3454
3455 /* Sends a message to the server to request authentication fd forwarding. */
3456
3457 void
3458 auth_request_forwarding(void)
3459 {
3460 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
3461 packet_send();
3462 packet_write_wait();
3463 }
NetBSD on the FriendlyARM MINI2440