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- djm@cvs.openbsd.org 2005/07/16 01:35:24
[openssh-git.git] / channels.c
blobb7ff85007b25316699ba2f1636c623a0ca295584
1 /*
2 * Author: Tatu Ylonen <ylo@cs.hut.fi>
3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
4 * All rights reserved
5 * This file contains functions for generic socket connection forwarding.
6 * There is also code for initiating connection forwarding for X11 connections,
7 * arbitrary tcp/ip connections, and the authentication agent connection.
8 *
9 * As far as I am concerned, the code I have written for this software
10 * can be used freely for any purpose. Any derived versions of this
11 * software must be clearly marked as such, and if the derived work is
12 * incompatible with the protocol description in the RFC file, it must be
13 * called by a name other than "ssh" or "Secure Shell".
14 *
15 * SSH2 support added by Markus Friedl.
16 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved.
17 * Copyright (c) 1999 Dug Song. All rights reserved.
18 * Copyright (c) 1999 Theo de Raadt. All rights reserved.
19 *
20 * Redistribution and use in source and binary forms, with or without
21 * modification, are permitted provided that the following conditions
22 * are met:
23 * 1. Redistributions of source code must retain the above copyright
24 * notice, this list of conditions and the following disclaimer.
25 * 2. Redistributions in binary form must reproduce the above copyright
26 * notice, this list of conditions and the following disclaimer in the
27 * documentation and/or other materials provided with the distribution.
28 *
29 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
30 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
31 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
32 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
33 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
34 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
35 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
36 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
37 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
38 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
39 */
40
41 #include "includes.h"
42 RCSID("$OpenBSD: channels.c,v 1.221 2005/07/16 01:35:24 djm Exp $");
43
44 #include "ssh.h"
45 #include "ssh1.h"
46 #include "ssh2.h"
47 #include "packet.h"
48 #include "xmalloc.h"
49 #include "log.h"
50 #include "misc.h"
51 #include "channels.h"
52 #include "compat.h"
53 #include "canohost.h"
54 #include "key.h"
55 #include "authfd.h"
56 #include "pathnames.h"
57 #include "bufaux.h"
58
59 /* -- channel core */
60
61 #define CHAN_RBUF 16*1024
62
63 /*
64 * Pointer to an array containing all allocated channels. The array is
65 * dynamically extended as needed.
66 */
67 static Channel **channels = NULL;
68
69 /*
70 * Size of the channel array. All slots of the array must always be
71 * initialized (at least the type field); unused slots set to NULL
72 */
73 static u_int channels_alloc = 0;
74
75 /*
76 * Maximum file descriptor value used in any of the channels. This is
77 * updated in channel_new.
78 */
79 static int channel_max_fd = 0;
80
81
82 /* -- tcp forwarding */
83
84 /*
85 * Data structure for storing which hosts are permitted for forward requests.
86 * The local sides of any remote forwards are stored in this array to prevent
87 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local
88 * network (which might be behind a firewall).
89 */
90 typedef struct {
91 char *host_to_connect; /* Connect to 'host'. */
92 u_short port_to_connect; /* Connect to 'port'. */
93 u_short listen_port; /* Remote side should listen port number. */
94 } ForwardPermission;
95
96 /* List of all permitted host/port pairs to connect. */
97 static ForwardPermission permitted_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
98
99 /* Number of permitted host/port pairs in the array. */
100 static int num_permitted_opens = 0;
101 /*
102 * If this is true, all opens are permitted. This is the case on the server
103 * on which we have to trust the client anyway, and the user could do
104 * anything after logging in anyway.
105 */
106 static int all_opens_permitted = 0;
107
108
109 /* -- X11 forwarding */
110
111 /* Maximum number of fake X11 displays to try. */
112 #define MAX_DISPLAYS 1000
113
114 /* Saved X11 local (client) display. */
115 static char *x11_saved_display = NULL;
116
117 /* Saved X11 authentication protocol name. */
118 static char *x11_saved_proto = NULL;
119
120 /* Saved X11 authentication data. This is the real data. */
121 static char *x11_saved_data = NULL;
122 static u_int x11_saved_data_len = 0;
123
124 /*
125 * Fake X11 authentication data. This is what the server will be sending us;
126 * we should replace any occurrences of this by the real data.
127 */
128 static char *x11_fake_data = NULL;
129 static u_int x11_fake_data_len;
130
131
132 /* -- agent forwarding */
133
134 #define NUM_SOCKS 10
135
136 /* AF_UNSPEC or AF_INET or AF_INET6 */
137 static int IPv4or6 = AF_UNSPEC;
138
139 /* helper */
140 static void port_open_helper(Channel *c, char *rtype);
141
142 /* -- channel core */
143
144 Channel *
145 channel_lookup(int id)
146 {
147 Channel *c;
148
149 if (id < 0 || (u_int)id >= channels_alloc) {
150 logit("channel_lookup: %d: bad id", id);
151 return NULL;
152 }
153 c = channels[id];
154 if (c == NULL) {
155 logit("channel_lookup: %d: bad id: channel free", id);
156 return NULL;
157 }
158 return c;
159 }
160
161 /*
162 * Register filedescriptors for a channel, used when allocating a channel or
163 * when the channel consumer/producer is ready, e.g. shell exec'd
164 */
165
166 static void
167 channel_register_fds(Channel *c, int rfd, int wfd, int efd,
168 int extusage, int nonblock)
169 {
170 /* Update the maximum file descriptor value. */
171 channel_max_fd = MAX(channel_max_fd, rfd);
172 channel_max_fd = MAX(channel_max_fd, wfd);
173 channel_max_fd = MAX(channel_max_fd, efd);
174
175 /* XXX set close-on-exec -markus */
176
177 c->rfd = rfd;
178 c->wfd = wfd;
179 c->sock = (rfd == wfd) ? rfd : -1;
180 c->ctl_fd = -1; /* XXX: set elsewhere */
181 c->efd = efd;
182 c->extended_usage = extusage;
183
184 /* XXX ugly hack: nonblock is only set by the server */
185 if (nonblock && isatty(c->rfd)) {
186 debug2("channel %d: rfd %d isatty", c->self, c->rfd);
187 c->isatty = 1;
188 if (!isatty(c->wfd)) {
189 error("channel %d: wfd %d is not a tty?",
190 c->self, c->wfd);
191 }
192 } else {
193 c->isatty = 0;
194 }
195 c->wfd_isatty = isatty(c->wfd);
196
197 /* enable nonblocking mode */
198 if (nonblock) {
199 if (rfd != -1)
200 set_nonblock(rfd);
201 if (wfd != -1)
202 set_nonblock(wfd);
203 if (efd != -1)
204 set_nonblock(efd);
205 }
206 }
207
208 /*
209 * Allocate a new channel object and set its type and socket. This will cause
210 * remote_name to be freed.
211 */
212
213 Channel *
214 channel_new(char *ctype, int type, int rfd, int wfd, int efd,
215 u_int window, u_int maxpack, int extusage, char *remote_name, int nonblock)
216 {
217 int found;
218 u_int i;
219 Channel *c;
220
221 /* Do initial allocation if this is the first call. */
222 if (channels_alloc == 0) {
223 channels_alloc = 10;
224 channels = xmalloc(channels_alloc * sizeof(Channel *));
225 for (i = 0; i < channels_alloc; i++)
226 channels[i] = NULL;
227 }
228 /* Try to find a free slot where to put the new channel. */
229 for (found = -1, i = 0; i < channels_alloc; i++)
230 if (channels[i] == NULL) {
231 /* Found a free slot. */
232 found = (int)i;
233 break;
234 }
235 if (found < 0) {
236 /* There are no free slots. Take last+1 slot and expand the array. */
237 found = channels_alloc;
238 if (channels_alloc > 10000)
239 fatal("channel_new: internal error: channels_alloc %d "
240 "too big.", channels_alloc);
241 channels = xrealloc(channels,
242 (channels_alloc + 10) * sizeof(Channel *));
243 channels_alloc += 10;
244 debug2("channel: expanding %d", channels_alloc);
245 for (i = found; i < channels_alloc; i++)
246 channels[i] = NULL;
247 }
248 /* Initialize and return new channel. */
249 c = channels[found] = xmalloc(sizeof(Channel));
250 memset(c, 0, sizeof(Channel));
251 buffer_init(&c->input);
252 buffer_init(&c->output);
253 buffer_init(&c->extended);
254 c->ostate = CHAN_OUTPUT_OPEN;
255 c->istate = CHAN_INPUT_OPEN;
256 c->flags = 0;
257 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
258 c->self = found;
259 c->type = type;
260 c->ctype = ctype;
261 c->local_window = window;
262 c->local_window_max = window;
263 c->local_consumed = 0;
264 c->local_maxpacket = maxpack;
265 c->remote_id = -1;
266 c->remote_name = xstrdup(remote_name);
267 c->remote_window = 0;
268 c->remote_maxpacket = 0;
269 c->force_drain = 0;
270 c->single_connection = 0;
271 c->detach_user = NULL;
272 c->confirm = NULL;
273 c->confirm_ctx = NULL;
274 c->input_filter = NULL;
275 debug("channel %d: new [%s]", found, remote_name);
276 return c;
277 }
278
279 static int
280 channel_find_maxfd(void)
281 {
282 u_int i;
283 int max = 0;
284 Channel *c;
285
286 for (i = 0; i < channels_alloc; i++) {
287 c = channels[i];
288 if (c != NULL) {
289 max = MAX(max, c->rfd);
290 max = MAX(max, c->wfd);
291 max = MAX(max, c->efd);
292 }
293 }
294 return max;
295 }
296
297 int
298 channel_close_fd(int *fdp)
299 {
300 int ret = 0, fd = *fdp;
301
302 if (fd != -1) {
303 ret = close(fd);
304 *fdp = -1;
305 if (fd == channel_max_fd)
306 channel_max_fd = channel_find_maxfd();
307 }
308 return ret;
309 }
310
311 /* Close all channel fd/socket. */
312
313 static void
314 channel_close_fds(Channel *c)
315 {
316 debug3("channel %d: close_fds r %d w %d e %d c %d",
317 c->self, c->rfd, c->wfd, c->efd, c->ctl_fd);
318
319 channel_close_fd(&c->sock);
320 channel_close_fd(&c->ctl_fd);
321 channel_close_fd(&c->rfd);
322 channel_close_fd(&c->wfd);
323 channel_close_fd(&c->efd);
324 }
325
326 /* Free the channel and close its fd/socket. */
327
328 void
329 channel_free(Channel *c)
330 {
331 char *s;
332 u_int i, n;
333
334 for (n = 0, i = 0; i < channels_alloc; i++)
335 if (channels[i])
336 n++;
337 debug("channel %d: free: %s, nchannels %u", c->self,
338 c->remote_name ? c->remote_name : "???", n);
339
340 s = channel_open_message();
341 debug3("channel %d: status: %s", c->self, s);
342 xfree(s);
343
344 if (c->sock != -1)
345 shutdown(c->sock, SHUT_RDWR);
346 if (c->ctl_fd != -1)
347 shutdown(c->ctl_fd, SHUT_RDWR);
348 channel_close_fds(c);
349 buffer_free(&c->input);
350 buffer_free(&c->output);
351 buffer_free(&c->extended);
352 if (c->remote_name) {
353 xfree(c->remote_name);
354 c->remote_name = NULL;
355 }
356 channels[c->self] = NULL;
357 xfree(c);
358 }
359
360 void
361 channel_free_all(void)
362 {
363 u_int i;
364
365 for (i = 0; i < channels_alloc; i++)
366 if (channels[i] != NULL)
367 channel_free(channels[i]);
368 }
369
370 /*
371 * Closes the sockets/fds of all channels. This is used to close extra file
372 * descriptors after a fork.
373 */
374
375 void
376 channel_close_all(void)
377 {
378 u_int i;
379
380 for (i = 0; i < channels_alloc; i++)
381 if (channels[i] != NULL)
382 channel_close_fds(channels[i]);
383 }
384
385 /*
386 * Stop listening to channels.
387 */
388
389 void
390 channel_stop_listening(void)
391 {
392 u_int i;
393 Channel *c;
394
395 for (i = 0; i < channels_alloc; i++) {
396 c = channels[i];
397 if (c != NULL) {
398 switch (c->type) {
399 case SSH_CHANNEL_AUTH_SOCKET:
400 case SSH_CHANNEL_PORT_LISTENER:
401 case SSH_CHANNEL_RPORT_LISTENER:
402 case SSH_CHANNEL_X11_LISTENER:
403 channel_close_fd(&c->sock);
404 channel_free(c);
405 break;
406 }
407 }
408 }
409 }
410
411 /*
412 * Returns true if no channel has too much buffered data, and false if one or
413 * more channel is overfull.
414 */
415
416 int
417 channel_not_very_much_buffered_data(void)
418 {
419 u_int i;
420 Channel *c;
421
422 for (i = 0; i < channels_alloc; i++) {
423 c = channels[i];
424 if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
425 #if 0
426 if (!compat20 &&
427 buffer_len(&c->input) > packet_get_maxsize()) {
428 debug2("channel %d: big input buffer %d",
429 c->self, buffer_len(&c->input));
430 return 0;
431 }
432 #endif
433 if (buffer_len(&c->output) > packet_get_maxsize()) {
434 debug2("channel %d: big output buffer %u > %u",
435 c->self, buffer_len(&c->output),
436 packet_get_maxsize());
437 return 0;
438 }
439 }
440 }
441 return 1;
442 }
443
444 /* Returns true if any channel is still open. */
445
446 int
447 channel_still_open(void)
448 {
449 u_int i;
450 Channel *c;
451
452 for (i = 0; i < channels_alloc; i++) {
453 c = channels[i];
454 if (c == NULL)
455 continue;
456 switch (c->type) {
457 case SSH_CHANNEL_X11_LISTENER:
458 case SSH_CHANNEL_PORT_LISTENER:
459 case SSH_CHANNEL_RPORT_LISTENER:
460 case SSH_CHANNEL_CLOSED:
461 case SSH_CHANNEL_AUTH_SOCKET:
462 case SSH_CHANNEL_DYNAMIC:
463 case SSH_CHANNEL_CONNECTING:
464 case SSH_CHANNEL_ZOMBIE:
465 continue;
466 case SSH_CHANNEL_LARVAL:
467 if (!compat20)
468 fatal("cannot happen: SSH_CHANNEL_LARVAL");
469 continue;
470 case SSH_CHANNEL_OPENING:
471 case SSH_CHANNEL_OPEN:
472 case SSH_CHANNEL_X11_OPEN:
473 return 1;
474 case SSH_CHANNEL_INPUT_DRAINING:
475 case SSH_CHANNEL_OUTPUT_DRAINING:
476 if (!compat13)
477 fatal("cannot happen: OUT_DRAIN");
478 return 1;
479 default:
480 fatal("channel_still_open: bad channel type %d", c->type);
481 /* NOTREACHED */
482 }
483 }
484 return 0;
485 }
486
487 /* Returns the id of an open channel suitable for keepaliving */
488
489 int
490 channel_find_open(void)
491 {
492 u_int i;
493 Channel *c;
494
495 for (i = 0; i < channels_alloc; i++) {
496 c = channels[i];
497 if (c == NULL || c->remote_id < 0)
498 continue;
499 switch (c->type) {
500 case SSH_CHANNEL_CLOSED:
501 case SSH_CHANNEL_DYNAMIC:
502 case SSH_CHANNEL_X11_LISTENER:
503 case SSH_CHANNEL_PORT_LISTENER:
504 case SSH_CHANNEL_RPORT_LISTENER:
505 case SSH_CHANNEL_OPENING:
506 case SSH_CHANNEL_CONNECTING:
507 case SSH_CHANNEL_ZOMBIE:
508 continue;
509 case SSH_CHANNEL_LARVAL:
510 case SSH_CHANNEL_AUTH_SOCKET:
511 case SSH_CHANNEL_OPEN:
512 case SSH_CHANNEL_X11_OPEN:
513 return i;
514 case SSH_CHANNEL_INPUT_DRAINING:
515 case SSH_CHANNEL_OUTPUT_DRAINING:
516 if (!compat13)
517 fatal("cannot happen: OUT_DRAIN");
518 return i;
519 default:
520 fatal("channel_find_open: bad channel type %d", c->type);
521 /* NOTREACHED */
522 }
523 }
524 return -1;
525 }
526
527
528 /*
529 * Returns a message describing the currently open forwarded connections,
530 * suitable for sending to the client. The message contains crlf pairs for
531 * newlines.
532 */
533
534 char *
535 channel_open_message(void)
536 {
537 Buffer buffer;
538 Channel *c;
539 char buf[1024], *cp;
540 u_int i;
541
542 buffer_init(&buffer);
543 snprintf(buf, sizeof buf, "The following connections are open:\r\n");
544 buffer_append(&buffer, buf, strlen(buf));
545 for (i = 0; i < channels_alloc; i++) {
546 c = channels[i];
547 if (c == NULL)
548 continue;
549 switch (c->type) {
550 case SSH_CHANNEL_X11_LISTENER:
551 case SSH_CHANNEL_PORT_LISTENER:
552 case SSH_CHANNEL_RPORT_LISTENER:
553 case SSH_CHANNEL_CLOSED:
554 case SSH_CHANNEL_AUTH_SOCKET:
555 case SSH_CHANNEL_ZOMBIE:
556 continue;
557 case SSH_CHANNEL_LARVAL:
558 case SSH_CHANNEL_OPENING:
559 case SSH_CHANNEL_CONNECTING:
560 case SSH_CHANNEL_DYNAMIC:
561 case SSH_CHANNEL_OPEN:
562 case SSH_CHANNEL_X11_OPEN:
563 case SSH_CHANNEL_INPUT_DRAINING:
564 case SSH_CHANNEL_OUTPUT_DRAINING:
565 snprintf(buf, sizeof buf,
566 " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d cfd %d)\r\n",
567 c->self, c->remote_name,
568 c->type, c->remote_id,
569 c->istate, buffer_len(&c->input),
570 c->ostate, buffer_len(&c->output),
571 c->rfd, c->wfd, c->ctl_fd);
572 buffer_append(&buffer, buf, strlen(buf));
573 continue;
574 default:
575 fatal("channel_open_message: bad channel type %d", c->type);
576 /* NOTREACHED */
577 }
578 }
579 buffer_append(&buffer, "\0", 1);
580 cp = xstrdup(buffer_ptr(&buffer));
581 buffer_free(&buffer);
582 return cp;
583 }
584
585 void
586 channel_send_open(int id)
587 {
588 Channel *c = channel_lookup(id);
589
590 if (c == NULL) {
591 logit("channel_send_open: %d: bad id", id);
592 return;
593 }
594 debug2("channel %d: send open", id);
595 packet_start(SSH2_MSG_CHANNEL_OPEN);
596 packet_put_cstring(c->ctype);
597 packet_put_int(c->self);
598 packet_put_int(c->local_window);
599 packet_put_int(c->local_maxpacket);
600 packet_send();
601 }
602
603 void
604 channel_request_start(int id, char *service, int wantconfirm)
605 {
606 Channel *c = channel_lookup(id);
607
608 if (c == NULL) {
609 logit("channel_request_start: %d: unknown channel id", id);
610 return;
611 }
612 debug2("channel %d: request %s confirm %d", id, service, wantconfirm);
613 packet_start(SSH2_MSG_CHANNEL_REQUEST);
614 packet_put_int(c->remote_id);
615 packet_put_cstring(service);
616 packet_put_char(wantconfirm);
617 }
618 void
619 channel_register_confirm(int id, channel_callback_fn *fn, void *ctx)
620 {
621 Channel *c = channel_lookup(id);
622
623 if (c == NULL) {
624 logit("channel_register_comfirm: %d: bad id", id);
625 return;
626 }
627 c->confirm = fn;
628 c->confirm_ctx = ctx;
629 }
630 void
631 channel_register_cleanup(int id, channel_callback_fn *fn)
632 {
633 Channel *c = channel_lookup(id);
634
635 if (c == NULL) {
636 logit("channel_register_cleanup: %d: bad id", id);
637 return;
638 }
639 c->detach_user = fn;
640 }
641 void
642 channel_cancel_cleanup(int id)
643 {
644 Channel *c = channel_lookup(id);
645
646 if (c == NULL) {
647 logit("channel_cancel_cleanup: %d: bad id", id);
648 return;
649 }
650 c->detach_user = NULL;
651 }
652 void
653 channel_register_filter(int id, channel_filter_fn *fn)
654 {
655 Channel *c = channel_lookup(id);
656
657 if (c == NULL) {
658 logit("channel_register_filter: %d: bad id", id);
659 return;
660 }
661 c->input_filter = fn;
662 }
663
664 void
665 channel_set_fds(int id, int rfd, int wfd, int efd,
666 int extusage, int nonblock, u_int window_max)
667 {
668 Channel *c = channel_lookup(id);
669
670 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
671 fatal("channel_activate for non-larval channel %d.", id);
672 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
673 c->type = SSH_CHANNEL_OPEN;
674 c->local_window = c->local_window_max = window_max;
675 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
676 packet_put_int(c->remote_id);
677 packet_put_int(c->local_window);
678 packet_send();
679 }
680
681 /*
682 * 'channel_pre*' are called just before select() to add any bits relevant to
683 * channels in the select bitmasks.
684 */
685 /*
686 * 'channel_post*': perform any appropriate operations for channels which
687 * have events pending.
688 */
689 typedef void chan_fn(Channel *c, fd_set * readset, fd_set * writeset);
690 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
691 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
692
693 static void
694 channel_pre_listener(Channel *c, fd_set * readset, fd_set * writeset)
695 {
696 FD_SET(c->sock, readset);
697 }
698
699 static void
700 channel_pre_connecting(Channel *c, fd_set * readset, fd_set * writeset)
701 {
702 debug3("channel %d: waiting for connection", c->self);
703 FD_SET(c->sock, writeset);
704 }
705
706 static void
707 channel_pre_open_13(Channel *c, fd_set * readset, fd_set * writeset)
708 {
709 if (buffer_len(&c->input) < packet_get_maxsize())
710 FD_SET(c->sock, readset);
711 if (buffer_len(&c->output) > 0)
712 FD_SET(c->sock, writeset);
713 }
714
715 static void
716 channel_pre_open(Channel *c, fd_set * readset, fd_set * writeset)
717 {
718 u_int limit = compat20 ? c->remote_window : packet_get_maxsize();
719
720 /* check buffer limits */
721 limit = MIN(limit, (BUFFER_MAX_LEN - BUFFER_MAX_CHUNK - CHAN_RBUF));
722
723 if (c->istate == CHAN_INPUT_OPEN &&
724 limit > 0 &&
725 buffer_len(&c->input) < limit)
726 FD_SET(c->rfd, readset);
727 if (c->ostate == CHAN_OUTPUT_OPEN ||
728 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
729 if (buffer_len(&c->output) > 0) {
730 FD_SET(c->wfd, writeset);
731 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
732 if (CHANNEL_EFD_OUTPUT_ACTIVE(c))
733 debug2("channel %d: obuf_empty delayed efd %d/(%d)",
734 c->self, c->efd, buffer_len(&c->extended));
735 else
736 chan_obuf_empty(c);
737 }
738 }
739 /** XXX check close conditions, too */
740 if (compat20 && c->efd != -1) {
741 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
742 buffer_len(&c->extended) > 0)
743 FD_SET(c->efd, writeset);
744 else if (!(c->flags & CHAN_EOF_SENT) &&
745 c->extended_usage == CHAN_EXTENDED_READ &&
746 buffer_len(&c->extended) < c->remote_window)
747 FD_SET(c->efd, readset);
748 }
749 /* XXX: What about efd? races? */
750 if (compat20 && c->ctl_fd != -1 &&
751 c->istate == CHAN_INPUT_OPEN && c->ostate == CHAN_OUTPUT_OPEN)
752 FD_SET(c->ctl_fd, readset);
753 }
754
755 static void
756 channel_pre_input_draining(Channel *c, fd_set * readset, fd_set * writeset)
757 {
758 if (buffer_len(&c->input) == 0) {
759 packet_start(SSH_MSG_CHANNEL_CLOSE);
760 packet_put_int(c->remote_id);
761 packet_send();
762 c->type = SSH_CHANNEL_CLOSED;
763 debug2("channel %d: closing after input drain.", c->self);
764 }
765 }
766
767 static void
768 channel_pre_output_draining(Channel *c, fd_set * readset, fd_set * writeset)
769 {
770 if (buffer_len(&c->output) == 0)
771 chan_mark_dead(c);
772 else
773 FD_SET(c->sock, writeset);
774 }
775
776 /*
777 * This is a special state for X11 authentication spoofing. An opened X11
778 * connection (when authentication spoofing is being done) remains in this
779 * state until the first packet has been completely read. The authentication
780 * data in that packet is then substituted by the real data if it matches the
781 * fake data, and the channel is put into normal mode.
782 * XXX All this happens at the client side.
783 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
784 */
785 static int
786 x11_open_helper(Buffer *b)
787 {
788 u_char *ucp;
789 u_int proto_len, data_len;
790
791 /* Check if the fixed size part of the packet is in buffer. */
792 if (buffer_len(b) < 12)
793 return 0;
794
795 /* Parse the lengths of variable-length fields. */
796 ucp = buffer_ptr(b);
797 if (ucp[0] == 0x42) { /* Byte order MSB first. */
798 proto_len = 256 * ucp[6] + ucp[7];
799 data_len = 256 * ucp[8] + ucp[9];
800 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
801 proto_len = ucp[6] + 256 * ucp[7];
802 data_len = ucp[8] + 256 * ucp[9];
803 } else {
804 debug2("Initial X11 packet contains bad byte order byte: 0x%x",
805 ucp[0]);
806 return -1;
807 }
808
809 /* Check if the whole packet is in buffer. */
810 if (buffer_len(b) <
811 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
812 return 0;
813
814 /* Check if authentication protocol matches. */
815 if (proto_len != strlen(x11_saved_proto) ||
816 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
817 debug2("X11 connection uses different authentication protocol.");
818 return -1;
819 }
820 /* Check if authentication data matches our fake data. */
821 if (data_len != x11_fake_data_len ||
822 memcmp(ucp + 12 + ((proto_len + 3) & ~3),
823 x11_fake_data, x11_fake_data_len) != 0) {
824 debug2("X11 auth data does not match fake data.");
825 return -1;
826 }
827 /* Check fake data length */
828 if (x11_fake_data_len != x11_saved_data_len) {
829 error("X11 fake_data_len %d != saved_data_len %d",
830 x11_fake_data_len, x11_saved_data_len);
831 return -1;
832 }
833 /*
834 * Received authentication protocol and data match
835 * our fake data. Substitute the fake data with real
836 * data.
837 */
838 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
839 x11_saved_data, x11_saved_data_len);
840 return 1;
841 }
842
843 static void
844 channel_pre_x11_open_13(Channel *c, fd_set * readset, fd_set * writeset)
845 {
846 int ret = x11_open_helper(&c->output);
847
848 if (ret == 1) {
849 /* Start normal processing for the channel. */
850 c->type = SSH_CHANNEL_OPEN;
851 channel_pre_open_13(c, readset, writeset);
852 } else if (ret == -1) {
853 /*
854 * We have received an X11 connection that has bad
855 * authentication information.
856 */
857 logit("X11 connection rejected because of wrong authentication.");
858 buffer_clear(&c->input);
859 buffer_clear(&c->output);
860 channel_close_fd(&c->sock);
861 c->sock = -1;
862 c->type = SSH_CHANNEL_CLOSED;
863 packet_start(SSH_MSG_CHANNEL_CLOSE);
864 packet_put_int(c->remote_id);
865 packet_send();
866 }
867 }
868
869 static void
870 channel_pre_x11_open(Channel *c, fd_set * readset, fd_set * writeset)
871 {
872 int ret = x11_open_helper(&c->output);
873
874 /* c->force_drain = 1; */
875
876 if (ret == 1) {
877 c->type = SSH_CHANNEL_OPEN;
878 channel_pre_open(c, readset, writeset);
879 } else if (ret == -1) {
880 logit("X11 connection rejected because of wrong authentication.");
881 debug2("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
882 chan_read_failed(c);
883 buffer_clear(&c->input);
884 chan_ibuf_empty(c);
885 buffer_clear(&c->output);
886 /* for proto v1, the peer will send an IEOF */
887 if (compat20)
888 chan_write_failed(c);
889 else
890 c->type = SSH_CHANNEL_OPEN;
891 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
892 }
893 }
894
895 /* try to decode a socks4 header */
896 static int
897 channel_decode_socks4(Channel *c, fd_set * readset, fd_set * writeset)
898 {
899 char *p, *host;
900 u_int len, have, i, found;
901 char username[256];
902 struct {
903 u_int8_t version;
904 u_int8_t command;
905 u_int16_t dest_port;
906 struct in_addr dest_addr;
907 } s4_req, s4_rsp;
908
909 debug2("channel %d: decode socks4", c->self);
910
911 have = buffer_len(&c->input);
912 len = sizeof(s4_req);
913 if (have < len)
914 return 0;
915 p = buffer_ptr(&c->input);
916 for (found = 0, i = len; i < have; i++) {
917 if (p[i] == '\0') {
918 found = 1;
919 break;
920 }
921 if (i > 1024) {
922 /* the peer is probably sending garbage */
923 debug("channel %d: decode socks4: too long",
924 c->self);
925 return -1;
926 }
927 }
928 if (!found)
929 return 0;
930 buffer_get(&c->input, (char *)&s4_req.version, 1);
931 buffer_get(&c->input, (char *)&s4_req.command, 1);
932 buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
933 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
934 have = buffer_len(&c->input);
935 p = buffer_ptr(&c->input);
936 len = strlen(p);
937 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
938 if (len > have)
939 fatal("channel %d: decode socks4: len %d > have %d",
940 c->self, len, have);
941 strlcpy(username, p, sizeof(username));
942 buffer_consume(&c->input, len);
943 buffer_consume(&c->input, 1); /* trailing '\0' */
944
945 host = inet_ntoa(s4_req.dest_addr);
946 strlcpy(c->path, host, sizeof(c->path));
947 c->host_port = ntohs(s4_req.dest_port);
948
949 debug2("channel %d: dynamic request: socks4 host %s port %u command %u",
950 c->self, host, c->host_port, s4_req.command);
951
952 if (s4_req.command != 1) {
953 debug("channel %d: cannot handle: socks4 cn %d",
954 c->self, s4_req.command);
955 return -1;
956 }
957 s4_rsp.version = 0; /* vn: 0 for reply */
958 s4_rsp.command = 90; /* cd: req granted */
959 s4_rsp.dest_port = 0; /* ignored */
960 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
961 buffer_append(&c->output, (char *)&s4_rsp, sizeof(s4_rsp));
962 return 1;
963 }
964
965 /* try to decode a socks5 header */
966 #define SSH_SOCKS5_AUTHDONE 0x1000
967 #define SSH_SOCKS5_NOAUTH 0x00
968 #define SSH_SOCKS5_IPV4 0x01
969 #define SSH_SOCKS5_DOMAIN 0x03
970 #define SSH_SOCKS5_IPV6 0x04
971 #define SSH_SOCKS5_CONNECT 0x01
972 #define SSH_SOCKS5_SUCCESS 0x00
973
974 static int
975 channel_decode_socks5(Channel *c, fd_set * readset, fd_set * writeset)
976 {
977 struct {
978 u_int8_t version;
979 u_int8_t command;
980 u_int8_t reserved;
981 u_int8_t atyp;
982 } s5_req, s5_rsp;
983 u_int16_t dest_port;
984 u_char *p, dest_addr[255+1];
985 u_int have, i, found, nmethods, addrlen, af;
986
987 debug2("channel %d: decode socks5", c->self);
988 p = buffer_ptr(&c->input);
989 if (p[0] != 0x05)
990 return -1;
991 have = buffer_len(&c->input);
992 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) {
993 /* format: ver | nmethods | methods */
994 if (have < 2)
995 return 0;
996 nmethods = p[1];
997 if (have < nmethods + 2)
998 return 0;
999 /* look for method: "NO AUTHENTICATION REQUIRED" */
1000 for (found = 0, i = 2 ; i < nmethods + 2; i++) {
1001 if (p[i] == SSH_SOCKS5_NOAUTH ) {
1002 found = 1;
1003 break;
1004 }
1005 }
1006 if (!found) {
1007 debug("channel %d: method SSH_SOCKS5_NOAUTH not found",
1008 c->self);
1009 return -1;
1010 }
1011 buffer_consume(&c->input, nmethods + 2);
1012 buffer_put_char(&c->output, 0x05); /* version */
1013 buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH); /* method */
1014 FD_SET(c->sock, writeset);
1015 c->flags |= SSH_SOCKS5_AUTHDONE;
1016 debug2("channel %d: socks5 auth done", c->self);
1017 return 0; /* need more */
1018 }
1019 debug2("channel %d: socks5 post auth", c->self);
1020 if (have < sizeof(s5_req)+1)
1021 return 0; /* need more */
1022 memcpy((char *)&s5_req, p, sizeof(s5_req));
1023 if (s5_req.version != 0x05 ||
1024 s5_req.command != SSH_SOCKS5_CONNECT ||
1025 s5_req.reserved != 0x00) {
1026 debug2("channel %d: only socks5 connect supported", c->self);
1027 return -1;
1028 }
1029 switch (s5_req.atyp){
1030 case SSH_SOCKS5_IPV4:
1031 addrlen = 4;
1032 af = AF_INET;
1033 break;
1034 case SSH_SOCKS5_DOMAIN:
1035 addrlen = p[sizeof(s5_req)];
1036 af = -1;
1037 break;
1038 case SSH_SOCKS5_IPV6:
1039 addrlen = 16;
1040 af = AF_INET6;
1041 break;
1042 default:
1043 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp);
1044 return -1;
1045 }
1046 if (have < 4 + addrlen + 2)
1047 return 0;
1048 buffer_consume(&c->input, sizeof(s5_req));
1049 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1050 buffer_consume(&c->input, 1); /* host string length */
1051 buffer_get(&c->input, (char *)&dest_addr, addrlen);
1052 buffer_get(&c->input, (char *)&dest_port, 2);
1053 dest_addr[addrlen] = '\0';
1054 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1055 strlcpy(c->path, (char *)dest_addr, sizeof(c->path));
1056 else if (inet_ntop(af, dest_addr, c->path, sizeof(c->path)) == NULL)
1057 return -1;
1058 c->host_port = ntohs(dest_port);
1059
1060 debug2("channel %d: dynamic request: socks5 host %s port %u command %u",
1061 c->self, c->path, c->host_port, s5_req.command);
1062
1063 s5_rsp.version = 0x05;
1064 s5_rsp.command = SSH_SOCKS5_SUCCESS;
1065 s5_rsp.reserved = 0; /* ignored */
1066 s5_rsp.atyp = SSH_SOCKS5_IPV4;
1067 ((struct in_addr *)&dest_addr)->s_addr = INADDR_ANY;
1068 dest_port = 0; /* ignored */
1069
1070 buffer_append(&c->output, (char *)&s5_rsp, sizeof(s5_rsp));
1071 buffer_append(&c->output, (char *)&dest_addr, sizeof(struct in_addr));
1072 buffer_append(&c->output, (char *)&dest_port, sizeof(dest_port));
1073 return 1;
1074 }
1075
1076 /* dynamic port forwarding */
1077 static void
1078 channel_pre_dynamic(Channel *c, fd_set * readset, fd_set * writeset)
1079 {
1080 u_char *p;
1081 u_int have;
1082 int ret;
1083
1084 have = buffer_len(&c->input);
1085 c->delayed = 0;
1086 debug2("channel %d: pre_dynamic: have %d", c->self, have);
1087 /* buffer_dump(&c->input); */
1088 /* check if the fixed size part of the packet is in buffer. */
1089 if (have < 3) {
1090 /* need more */
1091 FD_SET(c->sock, readset);
1092 return;
1093 }
1094 /* try to guess the protocol */
1095 p = buffer_ptr(&c->input);
1096 switch (p[0]) {
1097 case 0x04:
1098 ret = channel_decode_socks4(c, readset, writeset);
1099 break;
1100 case 0x05:
1101 ret = channel_decode_socks5(c, readset, writeset);
1102 break;
1103 default:
1104 ret = -1;
1105 break;
1106 }
1107 if (ret < 0) {
1108 chan_mark_dead(c);
1109 } else if (ret == 0) {
1110 debug2("channel %d: pre_dynamic: need more", c->self);
1111 /* need more */
1112 FD_SET(c->sock, readset);
1113 } else {
1114 /* switch to the next state */
1115 c->type = SSH_CHANNEL_OPENING;
1116 port_open_helper(c, "direct-tcpip");
1117 }
1118 }
1119
1120 /* This is our fake X11 server socket. */
1121 static void
1122 channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset)
1123 {
1124 Channel *nc;
1125 struct sockaddr addr;
1126 int newsock;
1127 socklen_t addrlen;
1128 char buf[16384], *remote_ipaddr;
1129 int remote_port;
1130
1131 if (FD_ISSET(c->sock, readset)) {
1132 debug("X11 connection requested.");
1133 addrlen = sizeof(addr);
1134 newsock = accept(c->sock, &addr, &addrlen);
1135 if (c->single_connection) {
1136 debug2("single_connection: closing X11 listener.");
1137 channel_close_fd(&c->sock);
1138 chan_mark_dead(c);
1139 }
1140 if (newsock < 0) {
1141 error("accept: %.100s", strerror(errno));
1142 return;
1143 }
1144 set_nodelay(newsock);
1145 remote_ipaddr = get_peer_ipaddr(newsock);
1146 remote_port = get_peer_port(newsock);
1147 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1148 remote_ipaddr, remote_port);
1149
1150 nc = channel_new("accepted x11 socket",
1151 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1152 c->local_window_max, c->local_maxpacket, 0, buf, 1);
1153 if (compat20) {
1154 packet_start(SSH2_MSG_CHANNEL_OPEN);
1155 packet_put_cstring("x11");
1156 packet_put_int(nc->self);
1157 packet_put_int(nc->local_window_max);
1158 packet_put_int(nc->local_maxpacket);
1159 /* originator ipaddr and port */
1160 packet_put_cstring(remote_ipaddr);
1161 if (datafellows & SSH_BUG_X11FWD) {
1162 debug2("ssh2 x11 bug compat mode");
1163 } else {
1164 packet_put_int(remote_port);
1165 }
1166 packet_send();
1167 } else {
1168 packet_start(SSH_SMSG_X11_OPEN);
1169 packet_put_int(nc->self);
1170 if (packet_get_protocol_flags() &
1171 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1172 packet_put_cstring(buf);
1173 packet_send();
1174 }
1175 xfree(remote_ipaddr);
1176 }
1177 }
1178
1179 static void
1180 port_open_helper(Channel *c, char *rtype)
1181 {
1182 int direct;
1183 char buf[1024];
1184 char *remote_ipaddr = get_peer_ipaddr(c->sock);
1185 int remote_port = get_peer_port(c->sock);
1186
1187 direct = (strcmp(rtype, "direct-tcpip") == 0);
1188
1189 snprintf(buf, sizeof buf,
1190 "%s: listening port %d for %.100s port %d, "
1191 "connect from %.200s port %d",
1192 rtype, c->listening_port, c->path, c->host_port,
1193 remote_ipaddr, remote_port);
1194
1195 xfree(c->remote_name);
1196 c->remote_name = xstrdup(buf);
1197
1198 if (compat20) {
1199 packet_start(SSH2_MSG_CHANNEL_OPEN);
1200 packet_put_cstring(rtype);
1201 packet_put_int(c->self);
1202 packet_put_int(c->local_window_max);
1203 packet_put_int(c->local_maxpacket);
1204 if (direct) {
1205 /* target host, port */
1206 packet_put_cstring(c->path);
1207 packet_put_int(c->host_port);
1208 } else {
1209 /* listen address, port */
1210 packet_put_cstring(c->path);
1211 packet_put_int(c->listening_port);
1212 }
1213 /* originator host and port */
1214 packet_put_cstring(remote_ipaddr);
1215 packet_put_int((u_int)remote_port);
1216 packet_send();
1217 } else {
1218 packet_start(SSH_MSG_PORT_OPEN);
1219 packet_put_int(c->self);
1220 packet_put_cstring(c->path);
1221 packet_put_int(c->host_port);
1222 if (packet_get_protocol_flags() &
1223 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1224 packet_put_cstring(c->remote_name);
1225 packet_send();
1226 }
1227 xfree(remote_ipaddr);
1228 }
1229
1230 /*
1231 * This socket is listening for connections to a forwarded TCP/IP port.
1232 */
1233 static void
1234 channel_post_port_listener(Channel *c, fd_set * readset, fd_set * writeset)
1235 {
1236 Channel *nc;
1237 struct sockaddr addr;
1238 int newsock, nextstate;
1239 socklen_t addrlen;
1240 char *rtype;
1241
1242 if (FD_ISSET(c->sock, readset)) {
1243 debug("Connection to port %d forwarding "
1244 "to %.100s port %d requested.",
1245 c->listening_port, c->path, c->host_port);
1246
1247 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1248 nextstate = SSH_CHANNEL_OPENING;
1249 rtype = "forwarded-tcpip";
1250 } else {
1251 if (c->host_port == 0) {
1252 nextstate = SSH_CHANNEL_DYNAMIC;
1253 rtype = "dynamic-tcpip";
1254 } else {
1255 nextstate = SSH_CHANNEL_OPENING;
1256 rtype = "direct-tcpip";
1257 }
1258 }
1259
1260 addrlen = sizeof(addr);
1261 newsock = accept(c->sock, &addr, &addrlen);
1262 if (newsock < 0) {
1263 error("accept: %.100s", strerror(errno));
1264 return;
1265 }
1266 set_nodelay(newsock);
1267 nc = channel_new(rtype, nextstate, newsock, newsock, -1,
1268 c->local_window_max, c->local_maxpacket, 0, rtype, 1);
1269 nc->listening_port = c->listening_port;
1270 nc->host_port = c->host_port;
1271 strlcpy(nc->path, c->path, sizeof(nc->path));
1272
1273 if (nextstate == SSH_CHANNEL_DYNAMIC) {
1274 /*
1275 * do not call the channel_post handler until
1276 * this flag has been reset by a pre-handler.
1277 * otherwise the FD_ISSET calls might overflow
1278 */
1279 nc->delayed = 1;
1280 } else {
1281 port_open_helper(nc, rtype);
1282 }
1283 }
1284 }
1285
1286 /*
1287 * This is the authentication agent socket listening for connections from
1288 * clients.
1289 */
1290 static void
1291 channel_post_auth_listener(Channel *c, fd_set * readset, fd_set * writeset)
1292 {
1293 Channel *nc;
1294 int newsock;
1295 struct sockaddr addr;
1296 socklen_t addrlen;
1297
1298 if (FD_ISSET(c->sock, readset)) {
1299 addrlen = sizeof(addr);
1300 newsock = accept(c->sock, &addr, &addrlen);
1301 if (newsock < 0) {
1302 error("accept from auth socket: %.100s", strerror(errno));
1303 return;
1304 }
1305 nc = channel_new("accepted auth socket",
1306 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1307 c->local_window_max, c->local_maxpacket,
1308 0, "accepted auth socket", 1);
1309 if (compat20) {
1310 packet_start(SSH2_MSG_CHANNEL_OPEN);
1311 packet_put_cstring("auth-agent@openssh.com");
1312 packet_put_int(nc->self);
1313 packet_put_int(c->local_window_max);
1314 packet_put_int(c->local_maxpacket);
1315 } else {
1316 packet_start(SSH_SMSG_AGENT_OPEN);
1317 packet_put_int(nc->self);
1318 }
1319 packet_send();
1320 }
1321 }
1322
1323 static void
1324 channel_post_connecting(Channel *c, fd_set * readset, fd_set * writeset)
1325 {
1326 int err = 0;
1327 socklen_t sz = sizeof(err);
1328
1329 if (FD_ISSET(c->sock, writeset)) {
1330 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) {
1331 err = errno;
1332 error("getsockopt SO_ERROR failed");
1333 }
1334 if (err == 0) {
1335 debug("channel %d: connected", c->self);
1336 c->type = SSH_CHANNEL_OPEN;
1337 if (compat20) {
1338 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1339 packet_put_int(c->remote_id);
1340 packet_put_int(c->self);
1341 packet_put_int(c->local_window);
1342 packet_put_int(c->local_maxpacket);
1343 } else {
1344 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1345 packet_put_int(c->remote_id);
1346 packet_put_int(c->self);
1347 }
1348 } else {
1349 debug("channel %d: not connected: %s",
1350 c->self, strerror(err));
1351 if (compat20) {
1352 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1353 packet_put_int(c->remote_id);
1354 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1355 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1356 packet_put_cstring(strerror(err));
1357 packet_put_cstring("");
1358 }
1359 } else {
1360 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1361 packet_put_int(c->remote_id);
1362 }
1363 chan_mark_dead(c);
1364 }
1365 packet_send();
1366 }
1367 }
1368
1369 static int
1370 channel_handle_rfd(Channel *c, fd_set * readset, fd_set * writeset)
1371 {
1372 char buf[CHAN_RBUF];
1373 int len;
1374
1375 if (c->rfd != -1 &&
1376 FD_ISSET(c->rfd, readset)) {
1377 len = read(c->rfd, buf, sizeof(buf));
1378 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1379 return 1;
1380 if (len <= 0) {
1381 debug2("channel %d: read<=0 rfd %d len %d",
1382 c->self, c->rfd, len);
1383 if (c->type != SSH_CHANNEL_OPEN) {
1384 debug2("channel %d: not open", c->self);
1385 chan_mark_dead(c);
1386 return -1;
1387 } else if (compat13) {
1388 buffer_clear(&c->output);
1389 c->type = SSH_CHANNEL_INPUT_DRAINING;
1390 debug2("channel %d: input draining.", c->self);
1391 } else {
1392 chan_read_failed(c);
1393 }
1394 return -1;
1395 }
1396 if (c->input_filter != NULL) {
1397 if (c->input_filter(c, buf, len) == -1) {
1398 debug2("channel %d: filter stops", c->self);
1399 chan_read_failed(c);
1400 }
1401 } else {
1402 buffer_append(&c->input, buf, len);
1403 }
1404 }
1405 return 1;
1406 }
1407 static int
1408 channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset)
1409 {
1410 struct termios tio;
1411 u_char *data;
1412 u_int dlen;
1413 int len;
1414
1415 /* Send buffered output data to the socket. */
1416 if (c->wfd != -1 &&
1417 FD_ISSET(c->wfd, writeset) &&
1418 buffer_len(&c->output) > 0) {
1419 data = buffer_ptr(&c->output);
1420 dlen = buffer_len(&c->output);
1421 #ifdef _AIX
1422 /* XXX: Later AIX versions can't push as much data to tty */
1423 if (compat20 && c->wfd_isatty)
1424 dlen = MIN(dlen, 8*1024);
1425 #endif
1426 len = write(c->wfd, data, dlen);
1427 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1428 return 1;
1429 if (len <= 0) {
1430 if (c->type != SSH_CHANNEL_OPEN) {
1431 debug2("channel %d: not open", c->self);
1432 chan_mark_dead(c);
1433 return -1;
1434 } else if (compat13) {
1435 buffer_clear(&c->output);
1436 debug2("channel %d: input draining.", c->self);
1437 c->type = SSH_CHANNEL_INPUT_DRAINING;
1438 } else {
1439 chan_write_failed(c);
1440 }
1441 return -1;
1442 }
1443 if (compat20 && c->isatty && dlen >= 1 && data[0] != '\r') {
1444 if (tcgetattr(c->wfd, &tio) == 0 &&
1445 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1446 /*
1447 * Simulate echo to reduce the impact of
1448 * traffic analysis. We need to match the
1449 * size of a SSH2_MSG_CHANNEL_DATA message
1450 * (4 byte channel id + data)
1451 */
1452 packet_send_ignore(4 + len);
1453 packet_send();
1454 }
1455 }
1456 buffer_consume(&c->output, len);
1457 if (compat20 && len > 0) {
1458 c->local_consumed += len;
1459 }
1460 }
1461 return 1;
1462 }
1463 static int
1464 channel_handle_efd(Channel *c, fd_set * readset, fd_set * writeset)
1465 {
1466 char buf[CHAN_RBUF];
1467 int len;
1468
1469 /** XXX handle drain efd, too */
1470 if (c->efd != -1) {
1471 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1472 FD_ISSET(c->efd, writeset) &&
1473 buffer_len(&c->extended) > 0) {
1474 len = write(c->efd, buffer_ptr(&c->extended),
1475 buffer_len(&c->extended));
1476 debug2("channel %d: written %d to efd %d",
1477 c->self, len, c->efd);
1478 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1479 return 1;
1480 if (len <= 0) {
1481 debug2("channel %d: closing write-efd %d",
1482 c->self, c->efd);
1483 channel_close_fd(&c->efd);
1484 } else {
1485 buffer_consume(&c->extended, len);
1486 c->local_consumed += len;
1487 }
1488 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
1489 FD_ISSET(c->efd, readset)) {
1490 len = read(c->efd, buf, sizeof(buf));
1491 debug2("channel %d: read %d from efd %d",
1492 c->self, len, c->efd);
1493 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1494 return 1;
1495 if (len <= 0) {
1496 debug2("channel %d: closing read-efd %d",
1497 c->self, c->efd);
1498 channel_close_fd(&c->efd);
1499 } else {
1500 buffer_append(&c->extended, buf, len);
1501 }
1502 }
1503 }
1504 return 1;
1505 }
1506 static int
1507 channel_handle_ctl(Channel *c, fd_set * readset, fd_set * writeset)
1508 {
1509 char buf[16];
1510 int len;
1511
1512 /* Monitor control fd to detect if the slave client exits */
1513 if (c->ctl_fd != -1 && FD_ISSET(c->ctl_fd, readset)) {
1514 len = read(c->ctl_fd, buf, sizeof(buf));
1515 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1516 return 1;
1517 if (len <= 0) {
1518 debug2("channel %d: ctl read<=0", c->self);
1519 if (c->type != SSH_CHANNEL_OPEN) {
1520 debug2("channel %d: not open", c->self);
1521 chan_mark_dead(c);
1522 return -1;
1523 } else {
1524 chan_read_failed(c);
1525 chan_write_failed(c);
1526 }
1527 return -1;
1528 } else
1529 fatal("%s: unexpected data on ctl fd", __func__);
1530 }
1531 return 1;
1532 }
1533 static int
1534 channel_check_window(Channel *c)
1535 {
1536 if (c->type == SSH_CHANNEL_OPEN &&
1537 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1538 c->local_window < c->local_window_max/2 &&
1539 c->local_consumed > 0) {
1540 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1541 packet_put_int(c->remote_id);
1542 packet_put_int(c->local_consumed);
1543 packet_send();
1544 debug2("channel %d: window %d sent adjust %d",
1545 c->self, c->local_window,
1546 c->local_consumed);
1547 c->local_window += c->local_consumed;
1548 c->local_consumed = 0;
1549 }
1550 return 1;
1551 }
1552
1553 static void
1554 channel_post_open(Channel *c, fd_set * readset, fd_set * writeset)
1555 {
1556 if (c->delayed)
1557 return;
1558 channel_handle_rfd(c, readset, writeset);
1559 channel_handle_wfd(c, readset, writeset);
1560 if (!compat20)
1561 return;
1562 channel_handle_efd(c, readset, writeset);
1563 channel_handle_ctl(c, readset, writeset);
1564 channel_check_window(c);
1565 }
1566
1567 static void
1568 channel_post_output_drain_13(Channel *c, fd_set * readset, fd_set * writeset)
1569 {
1570 int len;
1571
1572 /* Send buffered output data to the socket. */
1573 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1574 len = write(c->sock, buffer_ptr(&c->output),
1575 buffer_len(&c->output));
1576 if (len <= 0)
1577 buffer_clear(&c->output);
1578 else
1579 buffer_consume(&c->output, len);
1580 }
1581 }
1582
1583 static void
1584 channel_handler_init_20(void)
1585 {
1586 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1587 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1588 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1589 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
1590 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1591 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1592 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1593 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1594
1595 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1596 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1597 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
1598 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1599 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1600 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1601 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1602 }
1603
1604 static void
1605 channel_handler_init_13(void)
1606 {
1607 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
1608 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
1609 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1610 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1611 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1612 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
1613 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1614 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1615 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1616
1617 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1618 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1619 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1620 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1621 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
1622 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1623 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1624 }
1625
1626 static void
1627 channel_handler_init_15(void)
1628 {
1629 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1630 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1631 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1632 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1633 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1634 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1635 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1636
1637 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1638 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1639 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1640 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1641 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1642 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1643 }
1644
1645 static void
1646 channel_handler_init(void)
1647 {
1648 int i;
1649
1650 for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
1651 channel_pre[i] = NULL;
1652 channel_post[i] = NULL;
1653 }
1654 if (compat20)
1655 channel_handler_init_20();
1656 else if (compat13)
1657 channel_handler_init_13();
1658 else
1659 channel_handler_init_15();
1660 }
1661
1662 /* gc dead channels */
1663 static void
1664 channel_garbage_collect(Channel *c)
1665 {
1666 if (c == NULL)
1667 return;
1668 if (c->detach_user != NULL) {
1669 if (!chan_is_dead(c, 0))
1670 return;
1671 debug2("channel %d: gc: notify user", c->self);
1672 c->detach_user(c->self, NULL);
1673 /* if we still have a callback */
1674 if (c->detach_user != NULL)
1675 return;
1676 debug2("channel %d: gc: user detached", c->self);
1677 }
1678 if (!chan_is_dead(c, 1))
1679 return;
1680 debug2("channel %d: garbage collecting", c->self);
1681 channel_free(c);
1682 }
1683
1684 static void
1685 channel_handler(chan_fn *ftab[], fd_set * readset, fd_set * writeset)
1686 {
1687 static int did_init = 0;
1688 u_int i;
1689 Channel *c;
1690
1691 if (!did_init) {
1692 channel_handler_init();
1693 did_init = 1;
1694 }
1695 for (i = 0; i < channels_alloc; i++) {
1696 c = channels[i];
1697 if (c == NULL)
1698 continue;
1699 if (ftab[c->type] != NULL)
1700 (*ftab[c->type])(c, readset, writeset);
1701 channel_garbage_collect(c);
1702 }
1703 }
1704
1705 /*
1706 * Allocate/update select bitmasks and add any bits relevant to channels in
1707 * select bitmasks.
1708 */
1709 void
1710 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
1711 u_int *nallocp, int rekeying)
1712 {
1713 u_int n, sz;
1714
1715 n = MAX(*maxfdp, channel_max_fd);
1716
1717 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask);
1718 /* perhaps check sz < nalloc/2 and shrink? */
1719 if (*readsetp == NULL || sz > *nallocp) {
1720 *readsetp = xrealloc(*readsetp, sz);
1721 *writesetp = xrealloc(*writesetp, sz);
1722 *nallocp = sz;
1723 }
1724 *maxfdp = n;
1725 memset(*readsetp, 0, sz);
1726 memset(*writesetp, 0, sz);
1727
1728 if (!rekeying)
1729 channel_handler(channel_pre, *readsetp, *writesetp);
1730 }
1731
1732 /*
1733 * After select, perform any appropriate operations for channels which have
1734 * events pending.
1735 */
1736 void
1737 channel_after_select(fd_set * readset, fd_set * writeset)
1738 {
1739 channel_handler(channel_post, readset, writeset);
1740 }
1741
1742
1743 /* If there is data to send to the connection, enqueue some of it now. */
1744
1745 void
1746 channel_output_poll(void)
1747 {
1748 Channel *c;
1749 u_int i, len;
1750
1751 for (i = 0; i < channels_alloc; i++) {
1752 c = channels[i];
1753 if (c == NULL)
1754 continue;
1755
1756 /*
1757 * We are only interested in channels that can have buffered
1758 * incoming data.
1759 */
1760 if (compat13) {
1761 if (c->type != SSH_CHANNEL_OPEN &&
1762 c->type != SSH_CHANNEL_INPUT_DRAINING)
1763 continue;
1764 } else {
1765 if (c->type != SSH_CHANNEL_OPEN)
1766 continue;
1767 }
1768 if (compat20 &&
1769 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
1770 /* XXX is this true? */
1771 debug3("channel %d: will not send data after close", c->self);
1772 continue;
1773 }
1774
1775 /* Get the amount of buffered data for this channel. */
1776 if ((c->istate == CHAN_INPUT_OPEN ||
1777 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
1778 (len = buffer_len(&c->input)) > 0) {
1779 /*
1780 * Send some data for the other side over the secure
1781 * connection.
1782 */
1783 if (compat20) {
1784 if (len > c->remote_window)
1785 len = c->remote_window;
1786 if (len > c->remote_maxpacket)
1787 len = c->remote_maxpacket;
1788 } else {
1789 if (packet_is_interactive()) {
1790 if (len > 1024)
1791 len = 512;
1792 } else {
1793 /* Keep the packets at reasonable size. */
1794 if (len > packet_get_maxsize()/2)
1795 len = packet_get_maxsize()/2;
1796 }
1797 }
1798 if (len > 0) {
1799 packet_start(compat20 ?
1800 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
1801 packet_put_int(c->remote_id);
1802 packet_put_string(buffer_ptr(&c->input), len);
1803 packet_send();
1804 buffer_consume(&c->input, len);
1805 c->remote_window -= len;
1806 }
1807 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1808 if (compat13)
1809 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
1810 /*
1811 * input-buffer is empty and read-socket shutdown:
1812 * tell peer, that we will not send more data: send IEOF.
1813 * hack for extended data: delay EOF if EFD still in use.
1814 */
1815 if (CHANNEL_EFD_INPUT_ACTIVE(c))
1816 debug2("channel %d: ibuf_empty delayed efd %d/(%d)",
1817 c->self, c->efd, buffer_len(&c->extended));
1818 else
1819 chan_ibuf_empty(c);
1820 }
1821 /* Send extended data, i.e. stderr */
1822 if (compat20 &&
1823 !(c->flags & CHAN_EOF_SENT) &&
1824 c->remote_window > 0 &&
1825 (len = buffer_len(&c->extended)) > 0 &&
1826 c->extended_usage == CHAN_EXTENDED_READ) {
1827 debug2("channel %d: rwin %u elen %u euse %d",
1828 c->self, c->remote_window, buffer_len(&c->extended),
1829 c->extended_usage);
1830 if (len > c->remote_window)
1831 len = c->remote_window;
1832 if (len > c->remote_maxpacket)
1833 len = c->remote_maxpacket;
1834 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
1835 packet_put_int(c->remote_id);
1836 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
1837 packet_put_string(buffer_ptr(&c->extended), len);
1838 packet_send();
1839 buffer_consume(&c->extended, len);
1840 c->remote_window -= len;
1841 debug2("channel %d: sent ext data %d", c->self, len);
1842 }
1843 }
1844 }
1845
1846
1847 /* -- protocol input */
1848
1849 void
1850 channel_input_data(int type, u_int32_t seq, void *ctxt)
1851 {
1852 int id;
1853 char *data;
1854 u_int data_len;
1855 Channel *c;
1856
1857 /* Get the channel number and verify it. */
1858 id = packet_get_int();
1859 c = channel_lookup(id);
1860 if (c == NULL)
1861 packet_disconnect("Received data for nonexistent channel %d.", id);
1862
1863 /* Ignore any data for non-open channels (might happen on close) */
1864 if (c->type != SSH_CHANNEL_OPEN &&
1865 c->type != SSH_CHANNEL_X11_OPEN)
1866 return;
1867
1868 /* Get the data. */
1869 data = packet_get_string(&data_len);
1870
1871 /*
1872 * Ignore data for protocol > 1.3 if output end is no longer open.
1873 * For protocol 2 the sending side is reducing its window as it sends
1874 * data, so we must 'fake' consumption of the data in order to ensure
1875 * that window updates are sent back. Otherwise the connection might
1876 * deadlock.
1877 */
1878 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) {
1879 if (compat20) {
1880 c->local_window -= data_len;
1881 c->local_consumed += data_len;
1882 }
1883 xfree(data);
1884 return;
1885 }
1886
1887 if (compat20) {
1888 if (data_len > c->local_maxpacket) {
1889 logit("channel %d: rcvd big packet %d, maxpack %d",
1890 c->self, data_len, c->local_maxpacket);
1891 }
1892 if (data_len > c->local_window) {
1893 logit("channel %d: rcvd too much data %d, win %d",
1894 c->self, data_len, c->local_window);
1895 xfree(data);
1896 return;
1897 }
1898 c->local_window -= data_len;
1899 }
1900 packet_check_eom();
1901 buffer_append(&c->output, data, data_len);
1902 xfree(data);
1903 }
1904
1905 void
1906 channel_input_extended_data(int type, u_int32_t seq, void *ctxt)
1907 {
1908 int id;
1909 char *data;
1910 u_int data_len, tcode;
1911 Channel *c;
1912
1913 /* Get the channel number and verify it. */
1914 id = packet_get_int();
1915 c = channel_lookup(id);
1916
1917 if (c == NULL)
1918 packet_disconnect("Received extended_data for bad channel %d.", id);
1919 if (c->type != SSH_CHANNEL_OPEN) {
1920 logit("channel %d: ext data for non open", id);
1921 return;
1922 }
1923 if (c->flags & CHAN_EOF_RCVD) {
1924 if (datafellows & SSH_BUG_EXTEOF)
1925 debug("channel %d: accepting ext data after eof", id);
1926 else
1927 packet_disconnect("Received extended_data after EOF "
1928 "on channel %d.", id);
1929 }
1930 tcode = packet_get_int();
1931 if (c->efd == -1 ||
1932 c->extended_usage != CHAN_EXTENDED_WRITE ||
1933 tcode != SSH2_EXTENDED_DATA_STDERR) {
1934 logit("channel %d: bad ext data", c->self);
1935 return;
1936 }
1937 data = packet_get_string(&data_len);
1938 packet_check_eom();
1939 if (data_len > c->local_window) {
1940 logit("channel %d: rcvd too much extended_data %d, win %d",
1941 c->self, data_len, c->local_window);
1942 xfree(data);
1943 return;
1944 }
1945 debug2("channel %d: rcvd ext data %d", c->self, data_len);
1946 c->local_window -= data_len;
1947 buffer_append(&c->extended, data, data_len);
1948 xfree(data);
1949 }
1950
1951 void
1952 channel_input_ieof(int type, u_int32_t seq, void *ctxt)
1953 {
1954 int id;
1955 Channel *c;
1956
1957 id = packet_get_int();
1958 packet_check_eom();
1959 c = channel_lookup(id);
1960 if (c == NULL)
1961 packet_disconnect("Received ieof for nonexistent channel %d.", id);
1962 chan_rcvd_ieof(c);
1963
1964 /* XXX force input close */
1965 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) {
1966 debug("channel %d: FORCE input drain", c->self);
1967 c->istate = CHAN_INPUT_WAIT_DRAIN;
1968 if (buffer_len(&c->input) == 0)
1969 chan_ibuf_empty(c);
1970 }
1971
1972 }
1973
1974 void
1975 channel_input_close(int type, u_int32_t seq, void *ctxt)
1976 {
1977 int id;
1978 Channel *c;
1979
1980 id = packet_get_int();
1981 packet_check_eom();
1982 c = channel_lookup(id);
1983 if (c == NULL)
1984 packet_disconnect("Received close for nonexistent channel %d.", id);
1985
1986 /*
1987 * Send a confirmation that we have closed the channel and no more
1988 * data is coming for it.
1989 */
1990 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
1991 packet_put_int(c->remote_id);
1992 packet_send();
1993
1994 /*
1995 * If the channel is in closed state, we have sent a close request,
1996 * and the other side will eventually respond with a confirmation.
1997 * Thus, we cannot free the channel here, because then there would be
1998 * no-one to receive the confirmation. The channel gets freed when
1999 * the confirmation arrives.
2000 */
2001 if (c->type != SSH_CHANNEL_CLOSED) {
2002 /*
2003 * Not a closed channel - mark it as draining, which will
2004 * cause it to be freed later.
2005 */
2006 buffer_clear(&c->input);
2007 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
2008 }
2009 }
2010
2011 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
2012 void
2013 channel_input_oclose(int type, u_int32_t seq, void *ctxt)
2014 {
2015 int id = packet_get_int();
2016 Channel *c = channel_lookup(id);
2017
2018 packet_check_eom();
2019 if (c == NULL)
2020 packet_disconnect("Received oclose for nonexistent channel %d.", id);
2021 chan_rcvd_oclose(c);
2022 }
2023
2024 void
2025 channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt)
2026 {
2027 int id = packet_get_int();
2028 Channel *c = channel_lookup(id);
2029
2030 packet_check_eom();
2031 if (c == NULL)
2032 packet_disconnect("Received close confirmation for "
2033 "out-of-range channel %d.", id);
2034 if (c->type != SSH_CHANNEL_CLOSED)
2035 packet_disconnect("Received close confirmation for "
2036 "non-closed channel %d (type %d).", id, c->type);
2037 channel_free(c);
2038 }
2039
2040 void
2041 channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt)
2042 {
2043 int id, remote_id;
2044 Channel *c;
2045
2046 id = packet_get_int();
2047 c = channel_lookup(id);
2048
2049 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2050 packet_disconnect("Received open confirmation for "
2051 "non-opening channel %d.", id);
2052 remote_id = packet_get_int();
2053 /* Record the remote channel number and mark that the channel is now open. */
2054 c->remote_id = remote_id;
2055 c->type = SSH_CHANNEL_OPEN;
2056
2057 if (compat20) {
2058 c->remote_window = packet_get_int();
2059 c->remote_maxpacket = packet_get_int();
2060 if (c->confirm) {
2061 debug2("callback start");
2062 c->confirm(c->self, c->confirm_ctx);
2063 debug2("callback done");
2064 }
2065 debug2("channel %d: open confirm rwindow %u rmax %u", c->self,
2066 c->remote_window, c->remote_maxpacket);
2067 }
2068 packet_check_eom();
2069 }
2070
2071 static char *
2072 reason2txt(int reason)
2073 {
2074 switch (reason) {
2075 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
2076 return "administratively prohibited";
2077 case SSH2_OPEN_CONNECT_FAILED:
2078 return "connect failed";
2079 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
2080 return "unknown channel type";
2081 case SSH2_OPEN_RESOURCE_SHORTAGE:
2082 return "resource shortage";
2083 }
2084 return "unknown reason";
2085 }
2086
2087 void
2088 channel_input_open_failure(int type, u_int32_t seq, void *ctxt)
2089 {
2090 int id, reason;
2091 char *msg = NULL, *lang = NULL;
2092 Channel *c;
2093
2094 id = packet_get_int();
2095 c = channel_lookup(id);
2096
2097 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2098 packet_disconnect("Received open failure for "
2099 "non-opening channel %d.", id);
2100 if (compat20) {
2101 reason = packet_get_int();
2102 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
2103 msg = packet_get_string(NULL);
2104 lang = packet_get_string(NULL);
2105 }
2106 logit("channel %d: open failed: %s%s%s", id,
2107 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
2108 if (msg != NULL)
2109 xfree(msg);
2110 if (lang != NULL)
2111 xfree(lang);
2112 }
2113 packet_check_eom();
2114 /* Free the channel. This will also close the socket. */
2115 channel_free(c);
2116 }
2117
2118 void
2119 channel_input_window_adjust(int type, u_int32_t seq, void *ctxt)
2120 {
2121 Channel *c;
2122 int id;
2123 u_int adjust;
2124
2125 if (!compat20)
2126 return;
2127
2128 /* Get the channel number and verify it. */
2129 id = packet_get_int();
2130 c = channel_lookup(id);
2131
2132 if (c == NULL || c->type != SSH_CHANNEL_OPEN) {
2133 logit("Received window adjust for "
2134 "non-open channel %d.", id);
2135 return;
2136 }
2137 adjust = packet_get_int();
2138 packet_check_eom();
2139 debug2("channel %d: rcvd adjust %u", id, adjust);
2140 c->remote_window += adjust;
2141 }
2142
2143 void
2144 channel_input_port_open(int type, u_int32_t seq, void *ctxt)
2145 {
2146 Channel *c = NULL;
2147 u_short host_port;
2148 char *host, *originator_string;
2149 int remote_id, sock = -1;
2150
2151 remote_id = packet_get_int();
2152 host = packet_get_string(NULL);
2153 host_port = packet_get_int();
2154
2155 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2156 originator_string = packet_get_string(NULL);
2157 } else {
2158 originator_string = xstrdup("unknown (remote did not supply name)");
2159 }
2160 packet_check_eom();
2161 sock = channel_connect_to(host, host_port);
2162 if (sock != -1) {
2163 c = channel_new("connected socket",
2164 SSH_CHANNEL_CONNECTING, sock, sock, -1, 0, 0, 0,
2165 originator_string, 1);
2166 c->remote_id = remote_id;
2167 }
2168 xfree(originator_string);
2169 if (c == NULL) {
2170 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2171 packet_put_int(remote_id);
2172 packet_send();
2173 }
2174 xfree(host);
2175 }
2176
2177
2178 /* -- tcp forwarding */
2179
2180 void
2181 channel_set_af(int af)
2182 {
2183 IPv4or6 = af;
2184 }
2185
2186 static int
2187 channel_setup_fwd_listener(int type, const char *listen_addr, u_short listen_port,
2188 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2189 {
2190 Channel *c;
2191 int sock, r, success = 0, on = 1, wildcard = 0, is_client;
2192 struct addrinfo hints, *ai, *aitop;
2193 const char *host, *addr;
2194 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2195
2196 host = (type == SSH_CHANNEL_RPORT_LISTENER) ?
2197 listen_addr : host_to_connect;
2198 is_client = (type == SSH_CHANNEL_PORT_LISTENER);
2199
2200 if (host == NULL) {
2201 error("No forward host name.");
2202 return 0;
2203 }
2204 if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) {
2205 error("Forward host name too long.");
2206 return 0;
2207 }
2208
2209 /*
2210 * Determine whether or not a port forward listens to loopback,
2211 * specified address or wildcard. On the client, a specified bind
2212 * address will always override gateway_ports. On the server, a
2213 * gateway_ports of 1 (``yes'') will override the client's
2214 * specification and force a wildcard bind, whereas a value of 2
2215 * (``clientspecified'') will bind to whatever address the client
2216 * asked for.
2217 *
2218 * Special-case listen_addrs are:
2219 *
2220 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR
2221 * "" (empty string), "*" -> wildcard v4/v6
2222 * "localhost" -> loopback v4/v6
2223 */
2224 addr = NULL;
2225 if (listen_addr == NULL) {
2226 /* No address specified: default to gateway_ports setting */
2227 if (gateway_ports)
2228 wildcard = 1;
2229 } else if (gateway_ports || is_client) {
2230 if (((datafellows & SSH_OLD_FORWARD_ADDR) &&
2231 strcmp(listen_addr, "0.0.0.0") == 0) ||
2232 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 ||
2233 (!is_client && gateway_ports == 1))
2234 wildcard = 1;
2235 else if (strcmp(listen_addr, "localhost") != 0)
2236 addr = listen_addr;
2237 }
2238
2239 debug3("channel_setup_fwd_listener: type %d wildcard %d addr %s",
2240 type, wildcard, (addr == NULL) ? "NULL" : addr);
2241
2242 /*
2243 * getaddrinfo returns a loopback address if the hostname is
2244 * set to NULL and hints.ai_flags is not AI_PASSIVE
2245 */
2246 memset(&hints, 0, sizeof(hints));
2247 hints.ai_family = IPv4or6;
2248 hints.ai_flags = wildcard ? AI_PASSIVE : 0;
2249 hints.ai_socktype = SOCK_STREAM;
2250 snprintf(strport, sizeof strport, "%d", listen_port);
2251 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) {
2252 if (addr == NULL) {
2253 /* This really shouldn't happen */
2254 packet_disconnect("getaddrinfo: fatal error: %s",
2255 gai_strerror(r));
2256 } else {
2257 error("channel_setup_fwd_listener: "
2258 "getaddrinfo(%.64s): %s", addr, gai_strerror(r));
2259 }
2260 return 0;
2261 }
2262
2263 for (ai = aitop; ai; ai = ai->ai_next) {
2264 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2265 continue;
2266 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2267 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2268 error("channel_setup_fwd_listener: getnameinfo failed");
2269 continue;
2270 }
2271 /* Create a port to listen for the host. */
2272 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2273 if (sock < 0) {
2274 /* this is no error since kernel may not support ipv6 */
2275 verbose("socket: %.100s", strerror(errno));
2276 continue;
2277 }
2278 /*
2279 * Set socket options.
2280 * Allow local port reuse in TIME_WAIT.
2281 */
2282 if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &on,
2283 sizeof(on)) == -1)
2284 error("setsockopt SO_REUSEADDR: %s", strerror(errno));
2285
2286 debug("Local forwarding listening on %s port %s.", ntop, strport);
2287
2288 /* Bind the socket to the address. */
2289 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2290 /* address can be in use ipv6 address is already bound */
2291 if (!ai->ai_next)
2292 error("bind: %.100s", strerror(errno));
2293 else
2294 verbose("bind: %.100s", strerror(errno));
2295
2296 close(sock);
2297 continue;
2298 }
2299 /* Start listening for connections on the socket. */
2300 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2301 error("listen: %.100s", strerror(errno));
2302 close(sock);
2303 continue;
2304 }
2305 /* Allocate a channel number for the socket. */
2306 c = channel_new("port listener", type, sock, sock, -1,
2307 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2308 0, "port listener", 1);
2309 strlcpy(c->path, host, sizeof(c->path));
2310 c->host_port = port_to_connect;
2311 c->listening_port = listen_port;
2312 success = 1;
2313 }
2314 if (success == 0)
2315 error("channel_setup_fwd_listener: cannot listen to port: %d",
2316 listen_port);
2317 freeaddrinfo(aitop);
2318 return success;
2319 }
2320
2321 int
2322 channel_cancel_rport_listener(const char *host, u_short port)
2323 {
2324 u_int i;
2325 int found = 0;
2326
2327 for (i = 0; i < channels_alloc; i++) {
2328 Channel *c = channels[i];
2329
2330 if (c != NULL && c->type == SSH_CHANNEL_RPORT_LISTENER &&
2331 strncmp(c->path, host, sizeof(c->path)) == 0 &&
2332 c->listening_port == port) {
2333 debug2("%s: close channel %d", __func__, i);
2334 channel_free(c);
2335 found = 1;
2336 }
2337 }
2338
2339 return (found);
2340 }
2341
2342 /* protocol local port fwd, used by ssh (and sshd in v1) */
2343 int
2344 channel_setup_local_fwd_listener(const char *listen_host, u_short listen_port,
2345 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2346 {
2347 return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER,
2348 listen_host, listen_port, host_to_connect, port_to_connect,
2349 gateway_ports);
2350 }
2351
2352 /* protocol v2 remote port fwd, used by sshd */
2353 int
2354 channel_setup_remote_fwd_listener(const char *listen_address,
2355 u_short listen_port, int gateway_ports)
2356 {
2357 return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER,
2358 listen_address, listen_port, NULL, 0, gateway_ports);
2359 }
2360
2361 /*
2362 * Initiate forwarding of connections to port "port" on remote host through
2363 * the secure channel to host:port from local side.
2364 */
2365
2366 void
2367 channel_request_remote_forwarding(const char *listen_host, u_short listen_port,
2368 const char *host_to_connect, u_short port_to_connect)
2369 {
2370 int type, success = 0;
2371
2372 /* Record locally that connection to this host/port is permitted. */
2373 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2374 fatal("channel_request_remote_forwarding: too many forwards");
2375
2376 /* Send the forward request to the remote side. */
2377 if (compat20) {
2378 const char *address_to_bind;
2379 if (listen_host == NULL)
2380 address_to_bind = "localhost";
2381 else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0)
2382 address_to_bind = "";
2383 else
2384 address_to_bind = listen_host;
2385
2386 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2387 packet_put_cstring("tcpip-forward");
2388 packet_put_char(1); /* boolean: want reply */
2389 packet_put_cstring(address_to_bind);
2390 packet_put_int(listen_port);
2391 packet_send();
2392 packet_write_wait();
2393 /* Assume that server accepts the request */
2394 success = 1;
2395 } else {
2396 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2397 packet_put_int(listen_port);
2398 packet_put_cstring(host_to_connect);
2399 packet_put_int(port_to_connect);
2400 packet_send();
2401 packet_write_wait();
2402
2403 /* Wait for response from the remote side. */
2404 type = packet_read();
2405 switch (type) {
2406 case SSH_SMSG_SUCCESS:
2407 success = 1;
2408 break;
2409 case SSH_SMSG_FAILURE:
2410 logit("Warning: Server denied remote port forwarding.");
2411 break;
2412 default:
2413 /* Unknown packet */
2414 packet_disconnect("Protocol error for port forward request:"
2415 "received packet type %d.", type);
2416 }
2417 }
2418 if (success) {
2419 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2420 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2421 permitted_opens[num_permitted_opens].listen_port = listen_port;
2422 num_permitted_opens++;
2423 }
2424 }
2425
2426 /*
2427 * Request cancellation of remote forwarding of connection host:port from
2428 * local side.
2429 */
2430 void
2431 channel_request_rforward_cancel(const char *host, u_short port)
2432 {
2433 int i;
2434
2435 if (!compat20)
2436 return;
2437
2438 for (i = 0; i < num_permitted_opens; i++) {
2439 if (permitted_opens[i].host_to_connect != NULL &&
2440 permitted_opens[i].listen_port == port)
2441 break;
2442 }
2443 if (i >= num_permitted_opens) {
2444 debug("%s: requested forward not found", __func__);
2445 return;
2446 }
2447 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2448 packet_put_cstring("cancel-tcpip-forward");
2449 packet_put_char(0);
2450 packet_put_cstring(host == NULL ? "" : host);
2451 packet_put_int(port);
2452 packet_send();
2453
2454 permitted_opens[i].listen_port = 0;
2455 permitted_opens[i].port_to_connect = 0;
2456 free(permitted_opens[i].host_to_connect);
2457 permitted_opens[i].host_to_connect = NULL;
2458 }
2459
2460 /*
2461 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
2462 * listening for the port, and sends back a success reply (or disconnect
2463 * message if there was an error). This never returns if there was an error.
2464 */
2465
2466 void
2467 channel_input_port_forward_request(int is_root, int gateway_ports)
2468 {
2469 u_short port, host_port;
2470 char *hostname;
2471
2472 /* Get arguments from the packet. */
2473 port = packet_get_int();
2474 hostname = packet_get_string(NULL);
2475 host_port = packet_get_int();
2476
2477 #ifndef HAVE_CYGWIN
2478 /*
2479 * Check that an unprivileged user is not trying to forward a
2480 * privileged port.
2481 */
2482 if (port < IPPORT_RESERVED && !is_root)
2483 packet_disconnect(
2484 "Requested forwarding of port %d but user is not root.",
2485 port);
2486 if (host_port == 0)
2487 packet_disconnect("Dynamic forwarding denied.");
2488 #endif
2489
2490 /* Initiate forwarding */
2491 channel_setup_local_fwd_listener(NULL, port, hostname,
2492 host_port, gateway_ports);
2493
2494 /* Free the argument string. */
2495 xfree(hostname);
2496 }
2497
2498 /*
2499 * Permits opening to any host/port if permitted_opens[] is empty. This is
2500 * usually called by the server, because the user could connect to any port
2501 * anyway, and the server has no way to know but to trust the client anyway.
2502 */
2503 void
2504 channel_permit_all_opens(void)
2505 {
2506 if (num_permitted_opens == 0)
2507 all_opens_permitted = 1;
2508 }
2509
2510 void
2511 channel_add_permitted_opens(char *host, int port)
2512 {
2513 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2514 fatal("channel_request_remote_forwarding: too many forwards");
2515 debug("allow port forwarding to host %s port %d", host, port);
2516
2517 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
2518 permitted_opens[num_permitted_opens].port_to_connect = port;
2519 num_permitted_opens++;
2520
2521 all_opens_permitted = 0;
2522 }
2523
2524 void
2525 channel_clear_permitted_opens(void)
2526 {
2527 int i;
2528
2529 for (i = 0; i < num_permitted_opens; i++)
2530 if (permitted_opens[i].host_to_connect != NULL)
2531 xfree(permitted_opens[i].host_to_connect);
2532 num_permitted_opens = 0;
2533
2534 }
2535
2536
2537 /* return socket to remote host, port */
2538 static int
2539 connect_to(const char *host, u_short port)
2540 {
2541 struct addrinfo hints, *ai, *aitop;
2542 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2543 int gaierr;
2544 int sock = -1;
2545
2546 memset(&hints, 0, sizeof(hints));
2547 hints.ai_family = IPv4or6;
2548 hints.ai_socktype = SOCK_STREAM;
2549 snprintf(strport, sizeof strport, "%d", port);
2550 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
2551 error("connect_to %.100s: unknown host (%s)", host,
2552 gai_strerror(gaierr));
2553 return -1;
2554 }
2555 for (ai = aitop; ai; ai = ai->ai_next) {
2556 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2557 continue;
2558 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2559 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2560 error("connect_to: getnameinfo failed");
2561 continue;
2562 }
2563 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2564 if (sock < 0) {
2565 if (ai->ai_next == NULL)
2566 error("socket: %.100s", strerror(errno));
2567 else
2568 verbose("socket: %.100s", strerror(errno));
2569 continue;
2570 }
2571 if (set_nonblock(sock) == -1)
2572 fatal("%s: set_nonblock(%d)", __func__, sock);
2573 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 &&
2574 errno != EINPROGRESS) {
2575 error("connect_to %.100s port %s: %.100s", ntop, strport,
2576 strerror(errno));
2577 close(sock);
2578 continue; /* fail -- try next */
2579 }
2580 break; /* success */
2581
2582 }
2583 freeaddrinfo(aitop);
2584 if (!ai) {
2585 error("connect_to %.100s port %d: failed.", host, port);
2586 return -1;
2587 }
2588 /* success */
2589 set_nodelay(sock);
2590 return sock;
2591 }
2592
2593 int
2594 channel_connect_by_listen_address(u_short listen_port)
2595 {
2596 int i;
2597
2598 for (i = 0; i < num_permitted_opens; i++)
2599 if (permitted_opens[i].host_to_connect != NULL &&
2600 permitted_opens[i].listen_port == listen_port)
2601 return connect_to(
2602 permitted_opens[i].host_to_connect,
2603 permitted_opens[i].port_to_connect);
2604 error("WARNING: Server requests forwarding for unknown listen_port %d",
2605 listen_port);
2606 return -1;
2607 }
2608
2609 /* Check if connecting to that port is permitted and connect. */
2610 int
2611 channel_connect_to(const char *host, u_short port)
2612 {
2613 int i, permit;
2614
2615 permit = all_opens_permitted;
2616 if (!permit) {
2617 for (i = 0; i < num_permitted_opens; i++)
2618 if (permitted_opens[i].host_to_connect != NULL &&
2619 permitted_opens[i].port_to_connect == port &&
2620 strcmp(permitted_opens[i].host_to_connect, host) == 0)
2621 permit = 1;
2622
2623 }
2624 if (!permit) {
2625 logit("Received request to connect to host %.100s port %d, "
2626 "but the request was denied.", host, port);
2627 return -1;
2628 }
2629 return connect_to(host, port);
2630 }
2631
2632 void
2633 channel_send_window_changes(void)
2634 {
2635 u_int i;
2636 struct winsize ws;
2637
2638 for (i = 0; i < channels_alloc; i++) {
2639 if (channels[i] == NULL || !channels[i]->client_tty ||
2640 channels[i]->type != SSH_CHANNEL_OPEN)
2641 continue;
2642 if (ioctl(channels[i]->rfd, TIOCGWINSZ, &ws) < 0)
2643 continue;
2644 channel_request_start(i, "window-change", 0);
2645 packet_put_int(ws.ws_col);
2646 packet_put_int(ws.ws_row);
2647 packet_put_int(ws.ws_xpixel);
2648 packet_put_int(ws.ws_ypixel);
2649 packet_send();
2650 }
2651 }
2652
2653 /* -- X11 forwarding */
2654
2655 /*
2656 * Creates an internet domain socket for listening for X11 connections.
2657 * Returns 0 and a suitable display number for the DISPLAY variable
2658 * stored in display_numberp , or -1 if an error occurs.
2659 */
2660 int
2661 x11_create_display_inet(int x11_display_offset, int x11_use_localhost,
2662 int single_connection, u_int *display_numberp)
2663 {
2664 Channel *nc = NULL;
2665 int display_number, sock;
2666 u_short port;
2667 struct addrinfo hints, *ai, *aitop;
2668 char strport[NI_MAXSERV];
2669 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
2670
2671 for (display_number = x11_display_offset;
2672 display_number < MAX_DISPLAYS;
2673 display_number++) {
2674 port = 6000 + display_number;
2675 memset(&hints, 0, sizeof(hints));
2676 hints.ai_family = IPv4or6;
2677 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE;
2678 hints.ai_socktype = SOCK_STREAM;
2679 snprintf(strport, sizeof strport, "%d", port);
2680 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
2681 error("getaddrinfo: %.100s", gai_strerror(gaierr));
2682 return -1;
2683 }
2684 for (ai = aitop; ai; ai = ai->ai_next) {
2685 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2686 continue;
2687 sock = socket(ai->ai_family, ai->ai_socktype,
2688 ai->ai_protocol);
2689 if (sock < 0) {
2690 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
2691 error("socket: %.100s", strerror(errno));
2692 freeaddrinfo(aitop);
2693 return -1;
2694 } else {
2695 debug("x11_create_display_inet: Socket family %d not supported",
2696 ai->ai_family);
2697 continue;
2698 }
2699 }
2700 #ifdef IPV6_V6ONLY
2701 if (ai->ai_family == AF_INET6) {
2702 int on = 1;
2703 if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) < 0)
2704 error("setsockopt IPV6_V6ONLY: %.100s", strerror(errno));
2705 }
2706 #endif
2707 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2708 debug2("bind port %d: %.100s", port, strerror(errno));
2709 close(sock);
2710
2711 if (ai->ai_next)
2712 continue;
2713
2714 for (n = 0; n < num_socks; n++) {
2715 close(socks[n]);
2716 }
2717 num_socks = 0;
2718 break;
2719 }
2720 socks[num_socks++] = sock;
2721 #ifndef DONT_TRY_OTHER_AF
2722 if (num_socks == NUM_SOCKS)
2723 break;
2724 #else
2725 if (x11_use_localhost) {
2726 if (num_socks == NUM_SOCKS)
2727 break;
2728 } else {
2729 break;
2730 }
2731 #endif
2732 }
2733 freeaddrinfo(aitop);
2734 if (num_socks > 0)
2735 break;
2736 }
2737 if (display_number >= MAX_DISPLAYS) {
2738 error("Failed to allocate internet-domain X11 display socket.");
2739 return -1;
2740 }
2741 /* Start listening for connections on the socket. */
2742 for (n = 0; n < num_socks; n++) {
2743 sock = socks[n];
2744 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2745 error("listen: %.100s", strerror(errno));
2746 close(sock);
2747 return -1;
2748 }
2749 }
2750
2751 /* Allocate a channel for each socket. */
2752 for (n = 0; n < num_socks; n++) {
2753 sock = socks[n];
2754 nc = channel_new("x11 listener",
2755 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
2756 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2757 0, "X11 inet listener", 1);
2758 nc->single_connection = single_connection;
2759 }
2760
2761 /* Return the display number for the DISPLAY environment variable. */
2762 *display_numberp = display_number;
2763 return (0);
2764 }
2765
2766 static int
2767 connect_local_xsocket(u_int dnr)
2768 {
2769 int sock;
2770 struct sockaddr_un addr;
2771
2772 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2773 if (sock < 0)
2774 error("socket: %.100s", strerror(errno));
2775 memset(&addr, 0, sizeof(addr));
2776 addr.sun_family = AF_UNIX;
2777 snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr);
2778 if (connect(sock, (struct sockaddr *) & addr, sizeof(addr)) == 0)
2779 return sock;
2780 close(sock);
2781 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
2782 return -1;
2783 }
2784
2785 int
2786 x11_connect_display(void)
2787 {
2788 int display_number, sock = 0;
2789 const char *display;
2790 char buf[1024], *cp;
2791 struct addrinfo hints, *ai, *aitop;
2792 char strport[NI_MAXSERV];
2793 int gaierr;
2794
2795 /* Try to open a socket for the local X server. */
2796 display = getenv("DISPLAY");
2797 if (!display) {
2798 error("DISPLAY not set.");
2799 return -1;
2800 }
2801 /*
2802 * Now we decode the value of the DISPLAY variable and make a
2803 * connection to the real X server.
2804 */
2805
2806 /*
2807 * Check if it is a unix domain socket. Unix domain displays are in
2808 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
2809 */
2810 if (strncmp(display, "unix:", 5) == 0 ||
2811 display[0] == ':') {
2812 /* Connect to the unix domain socket. */
2813 if (sscanf(strrchr(display, ':') + 1, "%d", &display_number) != 1) {
2814 error("Could not parse display number from DISPLAY: %.100s",
2815 display);
2816 return -1;
2817 }
2818 /* Create a socket. */
2819 sock = connect_local_xsocket(display_number);
2820 if (sock < 0)
2821 return -1;
2822
2823 /* OK, we now have a connection to the display. */
2824 return sock;
2825 }
2826 /*
2827 * Connect to an inet socket. The DISPLAY value is supposedly
2828 * hostname:d[.s], where hostname may also be numeric IP address.
2829 */
2830 strlcpy(buf, display, sizeof(buf));
2831 cp = strchr(buf, ':');
2832 if (!cp) {
2833 error("Could not find ':' in DISPLAY: %.100s", display);
2834 return -1;
2835 }
2836 *cp = 0;
2837 /* buf now contains the host name. But first we parse the display number. */
2838 if (sscanf(cp + 1, "%d", &display_number) != 1) {
2839 error("Could not parse display number from DISPLAY: %.100s",
2840 display);
2841 return -1;
2842 }
2843
2844 /* Look up the host address */
2845 memset(&hints, 0, sizeof(hints));
2846 hints.ai_family = IPv4or6;
2847 hints.ai_socktype = SOCK_STREAM;
2848 snprintf(strport, sizeof strport, "%d", 6000 + display_number);
2849 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
2850 error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr));
2851 return -1;
2852 }
2853 for (ai = aitop; ai; ai = ai->ai_next) {
2854 /* Create a socket. */
2855 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2856 if (sock < 0) {
2857 debug2("socket: %.100s", strerror(errno));
2858 continue;
2859 }
2860 /* Connect it to the display. */
2861 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2862 debug2("connect %.100s port %d: %.100s", buf,
2863 6000 + display_number, strerror(errno));
2864 close(sock);
2865 continue;
2866 }
2867 /* Success */
2868 break;
2869 }
2870 freeaddrinfo(aitop);
2871 if (!ai) {
2872 error("connect %.100s port %d: %.100s", buf, 6000 + display_number,
2873 strerror(errno));
2874 return -1;
2875 }
2876 set_nodelay(sock);
2877 return sock;
2878 }
2879
2880 /*
2881 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
2882 * the remote channel number. We should do whatever we want, and respond
2883 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
2884 */
2885
2886 void
2887 x11_input_open(int type, u_int32_t seq, void *ctxt)
2888 {
2889 Channel *c = NULL;
2890 int remote_id, sock = 0;
2891 char *remote_host;
2892
2893 debug("Received X11 open request.");
2894
2895 remote_id = packet_get_int();
2896
2897 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2898 remote_host = packet_get_string(NULL);
2899 } else {
2900 remote_host = xstrdup("unknown (remote did not supply name)");
2901 }
2902 packet_check_eom();
2903
2904 /* Obtain a connection to the real X display. */
2905 sock = x11_connect_display();
2906 if (sock != -1) {
2907 /* Allocate a channel for this connection. */
2908 c = channel_new("connected x11 socket",
2909 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
2910 remote_host, 1);
2911 c->remote_id = remote_id;
2912 c->force_drain = 1;
2913 }
2914 xfree(remote_host);
2915 if (c == NULL) {
2916 /* Send refusal to the remote host. */
2917 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2918 packet_put_int(remote_id);
2919 } else {
2920 /* Send a confirmation to the remote host. */
2921 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2922 packet_put_int(remote_id);
2923 packet_put_int(c->self);
2924 }
2925 packet_send();
2926 }
2927
2928 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
2929 void
2930 deny_input_open(int type, u_int32_t seq, void *ctxt)
2931 {
2932 int rchan = packet_get_int();
2933
2934 switch (type) {
2935 case SSH_SMSG_AGENT_OPEN:
2936 error("Warning: ssh server tried agent forwarding.");
2937 break;
2938 case SSH_SMSG_X11_OPEN:
2939 error("Warning: ssh server tried X11 forwarding.");
2940 break;
2941 default:
2942 error("deny_input_open: type %d", type);
2943 break;
2944 }
2945 error("Warning: this is probably a break in attempt by a malicious server.");
2946 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2947 packet_put_int(rchan);
2948 packet_send();
2949 }
2950
2951 /*
2952 * Requests forwarding of X11 connections, generates fake authentication
2953 * data, and enables authentication spoofing.
2954 * This should be called in the client only.
2955 */
2956 void
2957 x11_request_forwarding_with_spoofing(int client_session_id, const char *disp,
2958 const char *proto, const char *data)
2959 {
2960 u_int data_len = (u_int) strlen(data) / 2;
2961 u_int i, value;
2962 char *new_data;
2963 int screen_number;
2964 const char *cp;
2965 u_int32_t rnd = 0;
2966
2967 if (x11_saved_display == NULL)
2968 x11_saved_display = xstrdup(disp);
2969 else if (strcmp(disp, x11_saved_display) != 0) {
2970 error("x11_request_forwarding_with_spoofing: different "
2971 "$DISPLAY already forwarded");
2972 return;
2973 }
2974
2975 cp = disp;
2976 if (disp)
2977 cp = strchr(disp, ':');
2978 if (cp)
2979 cp = strchr(cp, '.');
2980 if (cp)
2981 screen_number = atoi(cp + 1);
2982 else
2983 screen_number = 0;
2984
2985 if (x11_saved_proto == NULL) {
2986 /* Save protocol name. */
2987 x11_saved_proto = xstrdup(proto);
2988 /*
2989 * Extract real authentication data and generate fake data
2990 * of the same length.
2991 */
2992 x11_saved_data = xmalloc(data_len);
2993 x11_fake_data = xmalloc(data_len);
2994 for (i = 0; i < data_len; i++) {
2995 if (sscanf(data + 2 * i, "%2x", &value) != 1)
2996 fatal("x11_request_forwarding: bad "
2997 "authentication data: %.100s", data);
2998 if (i % 4 == 0)
2999 rnd = arc4random();
3000 x11_saved_data[i] = value;
3001 x11_fake_data[i] = rnd & 0xff;
3002 rnd >>= 8;
3003 }
3004 x11_saved_data_len = data_len;
3005 x11_fake_data_len = data_len;
3006 }
3007
3008 /* Convert the fake data into hex. */
3009 new_data = tohex(x11_fake_data, data_len);
3010
3011 /* Send the request packet. */
3012 if (compat20) {
3013 channel_request_start(client_session_id, "x11-req", 0);
3014 packet_put_char(0); /* XXX bool single connection */
3015 } else {
3016 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
3017 }
3018 packet_put_cstring(proto);
3019 packet_put_cstring(new_data);
3020 packet_put_int(screen_number);
3021 packet_send();
3022 packet_write_wait();
3023 xfree(new_data);
3024 }
3025
3026
3027 /* -- agent forwarding */
3028
3029 /* Sends a message to the server to request authentication fd forwarding. */
3030
3031 void
3032 auth_request_forwarding(void)
3033 {
3034 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
3035 packet_send();
3036 packet_write_wait();
3037 }
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