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- (dtucker) [defines.h] Use SIZE_T_MAX for SIZE_MAX for platforms that have a
[openssh-git.git] / channels.c
blob1cd5004c47bb976c8542f8ab919db106205a39bc
1 /* $OpenBSD: channels.c,v 1.309 2010/08/05 13:08:42 djm Exp $ */
2 /*
3 * Author: Tatu Ylonen <ylo@cs.hut.fi>
4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5 * All rights reserved
6 * This file contains functions for generic socket connection forwarding.
7 * There is also code for initiating connection forwarding for X11 connections,
8 * arbitrary tcp/ip connections, and the authentication agent connection.
9 *
10 * As far as I am concerned, the code I have written for this software
11 * can be used freely for any purpose. Any derived versions of this
12 * software must be clearly marked as such, and if the derived work is
13 * incompatible with the protocol description in the RFC file, it must be
14 * called by a name other than "ssh" or "Secure Shell".
15 *
16 * SSH2 support added by Markus Friedl.
17 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved.
18 * Copyright (c) 1999 Dug Song. All rights reserved.
19 * Copyright (c) 1999 Theo de Raadt. All rights reserved.
20 *
21 * Redistribution and use in source and binary forms, with or without
22 * modification, are permitted provided that the following conditions
23 * are met:
24 * 1. Redistributions of source code must retain the above copyright
25 * notice, this list of conditions and the following disclaimer.
26 * 2. Redistributions in binary form must reproduce the above copyright
27 * notice, this list of conditions and the following disclaimer in the
28 * documentation and/or other materials provided with the distribution.
29 *
30 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
31 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
32 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
33 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
34 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
35 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
36 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
37 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
38 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
39 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
40 */
41
42 #include "includes.h"
43
44 #include <sys/types.h>
45 #include <sys/ioctl.h>
46 #include <sys/un.h>
47 #include <sys/socket.h>
48 #ifdef HAVE_SYS_TIME_H
49 # include <sys/time.h>
50 #endif
51
52 #include <netinet/in.h>
53 #include <arpa/inet.h>
54
55 #include <errno.h>
56 #include <fcntl.h>
57 #include <netdb.h>
58 #include <stdio.h>
59 #include <stdlib.h>
60 #include <string.h>
61 #include <termios.h>
62 #include <unistd.h>
63 #include <stdarg.h>
64
65 #include "openbsd-compat/sys-queue.h"
66 #include "xmalloc.h"
67 #include "ssh.h"
68 #include "ssh1.h"
69 #include "ssh2.h"
70 #include "packet.h"
71 #include "log.h"
72 #include "misc.h"
73 #include "buffer.h"
74 #include "channels.h"
75 #include "compat.h"
76 #include "canohost.h"
77 #include "key.h"
78 #include "authfd.h"
79 #include "pathnames.h"
80
81 /* -- channel core */
82
83 /*
84 * Pointer to an array containing all allocated channels. The array is
85 * dynamically extended as needed.
86 */
87 static Channel **channels = NULL;
88
89 /*
90 * Size of the channel array. All slots of the array must always be
91 * initialized (at least the type field); unused slots set to NULL
92 */
93 static u_int channels_alloc = 0;
94
95 /*
96 * Maximum file descriptor value used in any of the channels. This is
97 * updated in channel_new.
98 */
99 static int channel_max_fd = 0;
100
101
102 /* -- tcp forwarding */
103
104 /*
105 * Data structure for storing which hosts are permitted for forward requests.
106 * The local sides of any remote forwards are stored in this array to prevent
107 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local
108 * network (which might be behind a firewall).
109 */
110 typedef struct {
111 char *host_to_connect; /* Connect to 'host'. */
112 u_short port_to_connect; /* Connect to 'port'. */
113 u_short listen_port; /* Remote side should listen port number. */
114 } ForwardPermission;
115
116 /* List of all permitted host/port pairs to connect by the user. */
117 static ForwardPermission *permitted_opens = NULL;
118
119 /* List of all permitted host/port pairs to connect by the admin. */
120 static ForwardPermission *permitted_adm_opens = NULL;
121
122 /* Number of permitted host/port pairs in the array permitted by the user. */
123 static int num_permitted_opens = 0;
124
125 /* Number of permitted host/port pair in the array permitted by the admin. */
126 static int num_adm_permitted_opens = 0;
127
128 /*
129 * If this is true, all opens are permitted. This is the case on the server
130 * on which we have to trust the client anyway, and the user could do
131 * anything after logging in anyway.
132 */
133 static int all_opens_permitted = 0;
134
135
136 /* -- X11 forwarding */
137
138 /* Maximum number of fake X11 displays to try. */
139 #define MAX_DISPLAYS 1000
140
141 /* Saved X11 local (client) display. */
142 static char *x11_saved_display = NULL;
143
144 /* Saved X11 authentication protocol name. */
145 static char *x11_saved_proto = NULL;
146
147 /* Saved X11 authentication data. This is the real data. */
148 static char *x11_saved_data = NULL;
149 static u_int x11_saved_data_len = 0;
150
151 /*
152 * Fake X11 authentication data. This is what the server will be sending us;
153 * we should replace any occurrences of this by the real data.
154 */
155 static u_char *x11_fake_data = NULL;
156 static u_int x11_fake_data_len;
157
158
159 /* -- agent forwarding */
160
161 #define NUM_SOCKS 10
162
163 /* AF_UNSPEC or AF_INET or AF_INET6 */
164 static int IPv4or6 = AF_UNSPEC;
165
166 /* helper */
167 static void port_open_helper(Channel *c, char *rtype);
168
169 /* non-blocking connect helpers */
170 static int connect_next(struct channel_connect *);
171 static void channel_connect_ctx_free(struct channel_connect *);
172
173 /* -- channel core */
174
175 Channel *
176 channel_by_id(int id)
177 {
178 Channel *c;
179
180 if (id < 0 || (u_int)id >= channels_alloc) {
181 logit("channel_by_id: %d: bad id", id);
182 return NULL;
183 }
184 c = channels[id];
185 if (c == NULL) {
186 logit("channel_by_id: %d: bad id: channel free", id);
187 return NULL;
188 }
189 return c;
190 }
191
192 /*
193 * Returns the channel if it is allowed to receive protocol messages.
194 * Private channels, like listening sockets, may not receive messages.
195 */
196 Channel *
197 channel_lookup(int id)
198 {
199 Channel *c;
200
201 if ((c = channel_by_id(id)) == NULL)
202 return (NULL);
203
204 switch (c->type) {
205 case SSH_CHANNEL_X11_OPEN:
206 case SSH_CHANNEL_LARVAL:
207 case SSH_CHANNEL_CONNECTING:
208 case SSH_CHANNEL_DYNAMIC:
209 case SSH_CHANNEL_OPENING:
210 case SSH_CHANNEL_OPEN:
211 case SSH_CHANNEL_INPUT_DRAINING:
212 case SSH_CHANNEL_OUTPUT_DRAINING:
213 return (c);
214 }
215 logit("Non-public channel %d, type %d.", id, c->type);
216 return (NULL);
217 }
218
219 /*
220 * Register filedescriptors for a channel, used when allocating a channel or
221 * when the channel consumer/producer is ready, e.g. shell exec'd
222 */
223 static void
224 channel_register_fds(Channel *c, int rfd, int wfd, int efd,
225 int extusage, int nonblock, int is_tty)
226 {
227 /* Update the maximum file descriptor value. */
228 channel_max_fd = MAX(channel_max_fd, rfd);
229 channel_max_fd = MAX(channel_max_fd, wfd);
230 channel_max_fd = MAX(channel_max_fd, efd);
231
232 if (rfd != -1)
233 fcntl(rfd, F_SETFD, FD_CLOEXEC);
234 if (wfd != -1 && wfd != rfd)
235 fcntl(wfd, F_SETFD, FD_CLOEXEC);
236 if (efd != -1 && efd != rfd && efd != wfd)
237 fcntl(efd, F_SETFD, FD_CLOEXEC);
238
239 c->rfd = rfd;
240 c->wfd = wfd;
241 c->sock = (rfd == wfd) ? rfd : -1;
242 c->efd = efd;
243 c->extended_usage = extusage;
244
245 if ((c->isatty = is_tty) != 0)
246 debug2("channel %d: rfd %d isatty", c->self, c->rfd);
247 c->wfd_isatty = is_tty || isatty(c->wfd);
248
249 /* enable nonblocking mode */
250 if (nonblock) {
251 if (rfd != -1)
252 set_nonblock(rfd);
253 if (wfd != -1)
254 set_nonblock(wfd);
255 if (efd != -1)
256 set_nonblock(efd);
257 }
258 }
259
260 /*
261 * Allocate a new channel object and set its type and socket. This will cause
262 * remote_name to be freed.
263 */
264 Channel *
265 channel_new(char *ctype, int type, int rfd, int wfd, int efd,
266 u_int window, u_int maxpack, int extusage, char *remote_name, int nonblock)
267 {
268 int found;
269 u_int i;
270 Channel *c;
271
272 /* Do initial allocation if this is the first call. */
273 if (channels_alloc == 0) {
274 channels_alloc = 10;
275 channels = xcalloc(channels_alloc, sizeof(Channel *));
276 for (i = 0; i < channels_alloc; i++)
277 channels[i] = NULL;
278 }
279 /* Try to find a free slot where to put the new channel. */
280 for (found = -1, i = 0; i < channels_alloc; i++)
281 if (channels[i] == NULL) {
282 /* Found a free slot. */
283 found = (int)i;
284 break;
285 }
286 if (found < 0) {
287 /* There are no free slots. Take last+1 slot and expand the array. */
288 found = channels_alloc;
289 if (channels_alloc > 10000)
290 fatal("channel_new: internal error: channels_alloc %d "
291 "too big.", channels_alloc);
292 channels = xrealloc(channels, channels_alloc + 10,
293 sizeof(Channel *));
294 channels_alloc += 10;
295 debug2("channel: expanding %d", channels_alloc);
296 for (i = found; i < channels_alloc; i++)
297 channels[i] = NULL;
298 }
299 /* Initialize and return new channel. */
300 c = channels[found] = xcalloc(1, sizeof(Channel));
301 buffer_init(&c->input);
302 buffer_init(&c->output);
303 buffer_init(&c->extended);
304 c->path = NULL;
305 c->ostate = CHAN_OUTPUT_OPEN;
306 c->istate = CHAN_INPUT_OPEN;
307 c->flags = 0;
308 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock, 0);
309 c->self = found;
310 c->type = type;
311 c->ctype = ctype;
312 c->local_window = window;
313 c->local_window_max = window;
314 c->local_consumed = 0;
315 c->local_maxpacket = maxpack;
316 c->remote_id = -1;
317 c->remote_name = xstrdup(remote_name);
318 c->remote_window = 0;
319 c->remote_maxpacket = 0;
320 c->force_drain = 0;
321 c->single_connection = 0;
322 c->detach_user = NULL;
323 c->detach_close = 0;
324 c->open_confirm = NULL;
325 c->open_confirm_ctx = NULL;
326 c->input_filter = NULL;
327 c->output_filter = NULL;
328 c->filter_ctx = NULL;
329 c->filter_cleanup = NULL;
330 c->ctl_chan = -1;
331 c->mux_rcb = NULL;
332 c->mux_ctx = NULL;
333 c->mux_pause = 0;
334 c->delayed = 1; /* prevent call to channel_post handler */
335 TAILQ_INIT(&c->status_confirms);
336 debug("channel %d: new [%s]", found, remote_name);
337 return c;
338 }
339
340 static int
341 channel_find_maxfd(void)
342 {
343 u_int i;
344 int max = 0;
345 Channel *c;
346
347 for (i = 0; i < channels_alloc; i++) {
348 c = channels[i];
349 if (c != NULL) {
350 max = MAX(max, c->rfd);
351 max = MAX(max, c->wfd);
352 max = MAX(max, c->efd);
353 }
354 }
355 return max;
356 }
357
358 int
359 channel_close_fd(int *fdp)
360 {
361 int ret = 0, fd = *fdp;
362
363 if (fd != -1) {
364 ret = close(fd);
365 *fdp = -1;
366 if (fd == channel_max_fd)
367 channel_max_fd = channel_find_maxfd();
368 }
369 return ret;
370 }
371
372 /* Close all channel fd/socket. */
373 static void
374 channel_close_fds(Channel *c)
375 {
376 debug3("channel %d: close_fds r %d w %d e %d",
377 c->self, c->rfd, c->wfd, c->efd);
378
379 channel_close_fd(&c->sock);
380 channel_close_fd(&c->rfd);
381 channel_close_fd(&c->wfd);
382 channel_close_fd(&c->efd);
383 }
384
385 /* Free the channel and close its fd/socket. */
386 void
387 channel_free(Channel *c)
388 {
389 char *s;
390 u_int i, n;
391 struct channel_confirm *cc;
392
393 for (n = 0, i = 0; i < channels_alloc; i++)
394 if (channels[i])
395 n++;
396 debug("channel %d: free: %s, nchannels %u", c->self,
397 c->remote_name ? c->remote_name : "???", n);
398
399 s = channel_open_message();
400 debug3("channel %d: status: %s", c->self, s);
401 xfree(s);
402
403 if (c->sock != -1)
404 shutdown(c->sock, SHUT_RDWR);
405 channel_close_fds(c);
406 buffer_free(&c->input);
407 buffer_free(&c->output);
408 buffer_free(&c->extended);
409 if (c->remote_name) {
410 xfree(c->remote_name);
411 c->remote_name = NULL;
412 }
413 if (c->path) {
414 xfree(c->path);
415 c->path = NULL;
416 }
417 while ((cc = TAILQ_FIRST(&c->status_confirms)) != NULL) {
418 if (cc->abandon_cb != NULL)
419 cc->abandon_cb(c, cc->ctx);
420 TAILQ_REMOVE(&c->status_confirms, cc, entry);
421 bzero(cc, sizeof(*cc));
422 xfree(cc);
423 }
424 if (c->filter_cleanup != NULL && c->filter_ctx != NULL)
425 c->filter_cleanup(c->self, c->filter_ctx);
426 channels[c->self] = NULL;
427 xfree(c);
428 }
429
430 void
431 channel_free_all(void)
432 {
433 u_int i;
434
435 for (i = 0; i < channels_alloc; i++)
436 if (channels[i] != NULL)
437 channel_free(channels[i]);
438 }
439
440 /*
441 * Closes the sockets/fds of all channels. This is used to close extra file
442 * descriptors after a fork.
443 */
444 void
445 channel_close_all(void)
446 {
447 u_int i;
448
449 for (i = 0; i < channels_alloc; i++)
450 if (channels[i] != NULL)
451 channel_close_fds(channels[i]);
452 }
453
454 /*
455 * Stop listening to channels.
456 */
457 void
458 channel_stop_listening(void)
459 {
460 u_int i;
461 Channel *c;
462
463 for (i = 0; i < channels_alloc; i++) {
464 c = channels[i];
465 if (c != NULL) {
466 switch (c->type) {
467 case SSH_CHANNEL_AUTH_SOCKET:
468 case SSH_CHANNEL_PORT_LISTENER:
469 case SSH_CHANNEL_RPORT_LISTENER:
470 case SSH_CHANNEL_X11_LISTENER:
471 channel_close_fd(&c->sock);
472 channel_free(c);
473 break;
474 }
475 }
476 }
477 }
478
479 /*
480 * Returns true if no channel has too much buffered data, and false if one or
481 * more channel is overfull.
482 */
483 int
484 channel_not_very_much_buffered_data(void)
485 {
486 u_int i;
487 Channel *c;
488
489 for (i = 0; i < channels_alloc; i++) {
490 c = channels[i];
491 if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
492 #if 0
493 if (!compat20 &&
494 buffer_len(&c->input) > packet_get_maxsize()) {
495 debug2("channel %d: big input buffer %d",
496 c->self, buffer_len(&c->input));
497 return 0;
498 }
499 #endif
500 if (buffer_len(&c->output) > packet_get_maxsize()) {
501 debug2("channel %d: big output buffer %u > %u",
502 c->self, buffer_len(&c->output),
503 packet_get_maxsize());
504 return 0;
505 }
506 }
507 }
508 return 1;
509 }
510
511 /* Returns true if any channel is still open. */
512 int
513 channel_still_open(void)
514 {
515 u_int i;
516 Channel *c;
517
518 for (i = 0; i < channels_alloc; i++) {
519 c = channels[i];
520 if (c == NULL)
521 continue;
522 switch (c->type) {
523 case SSH_CHANNEL_X11_LISTENER:
524 case SSH_CHANNEL_PORT_LISTENER:
525 case SSH_CHANNEL_RPORT_LISTENER:
526 case SSH_CHANNEL_MUX_LISTENER:
527 case SSH_CHANNEL_CLOSED:
528 case SSH_CHANNEL_AUTH_SOCKET:
529 case SSH_CHANNEL_DYNAMIC:
530 case SSH_CHANNEL_CONNECTING:
531 case SSH_CHANNEL_ZOMBIE:
532 continue;
533 case SSH_CHANNEL_LARVAL:
534 if (!compat20)
535 fatal("cannot happen: SSH_CHANNEL_LARVAL");
536 continue;
537 case SSH_CHANNEL_OPENING:
538 case SSH_CHANNEL_OPEN:
539 case SSH_CHANNEL_X11_OPEN:
540 case SSH_CHANNEL_MUX_CLIENT:
541 return 1;
542 case SSH_CHANNEL_INPUT_DRAINING:
543 case SSH_CHANNEL_OUTPUT_DRAINING:
544 if (!compat13)
545 fatal("cannot happen: OUT_DRAIN");
546 return 1;
547 default:
548 fatal("channel_still_open: bad channel type %d", c->type);
549 /* NOTREACHED */
550 }
551 }
552 return 0;
553 }
554
555 /* Returns the id of an open channel suitable for keepaliving */
556 int
557 channel_find_open(void)
558 {
559 u_int i;
560 Channel *c;
561
562 for (i = 0; i < channels_alloc; i++) {
563 c = channels[i];
564 if (c == NULL || c->remote_id < 0)
565 continue;
566 switch (c->type) {
567 case SSH_CHANNEL_CLOSED:
568 case SSH_CHANNEL_DYNAMIC:
569 case SSH_CHANNEL_X11_LISTENER:
570 case SSH_CHANNEL_PORT_LISTENER:
571 case SSH_CHANNEL_RPORT_LISTENER:
572 case SSH_CHANNEL_MUX_LISTENER:
573 case SSH_CHANNEL_MUX_CLIENT:
574 case SSH_CHANNEL_OPENING:
575 case SSH_CHANNEL_CONNECTING:
576 case SSH_CHANNEL_ZOMBIE:
577 continue;
578 case SSH_CHANNEL_LARVAL:
579 case SSH_CHANNEL_AUTH_SOCKET:
580 case SSH_CHANNEL_OPEN:
581 case SSH_CHANNEL_X11_OPEN:
582 return i;
583 case SSH_CHANNEL_INPUT_DRAINING:
584 case SSH_CHANNEL_OUTPUT_DRAINING:
585 if (!compat13)
586 fatal("cannot happen: OUT_DRAIN");
587 return i;
588 default:
589 fatal("channel_find_open: bad channel type %d", c->type);
590 /* NOTREACHED */
591 }
592 }
593 return -1;
594 }
595
596
597 /*
598 * Returns a message describing the currently open forwarded connections,
599 * suitable for sending to the client. The message contains crlf pairs for
600 * newlines.
601 */
602 char *
603 channel_open_message(void)
604 {
605 Buffer buffer;
606 Channel *c;
607 char buf[1024], *cp;
608 u_int i;
609
610 buffer_init(&buffer);
611 snprintf(buf, sizeof buf, "The following connections are open:\r\n");
612 buffer_append(&buffer, buf, strlen(buf));
613 for (i = 0; i < channels_alloc; i++) {
614 c = channels[i];
615 if (c == NULL)
616 continue;
617 switch (c->type) {
618 case SSH_CHANNEL_X11_LISTENER:
619 case SSH_CHANNEL_PORT_LISTENER:
620 case SSH_CHANNEL_RPORT_LISTENER:
621 case SSH_CHANNEL_CLOSED:
622 case SSH_CHANNEL_AUTH_SOCKET:
623 case SSH_CHANNEL_ZOMBIE:
624 case SSH_CHANNEL_MUX_CLIENT:
625 case SSH_CHANNEL_MUX_LISTENER:
626 continue;
627 case SSH_CHANNEL_LARVAL:
628 case SSH_CHANNEL_OPENING:
629 case SSH_CHANNEL_CONNECTING:
630 case SSH_CHANNEL_DYNAMIC:
631 case SSH_CHANNEL_OPEN:
632 case SSH_CHANNEL_X11_OPEN:
633 case SSH_CHANNEL_INPUT_DRAINING:
634 case SSH_CHANNEL_OUTPUT_DRAINING:
635 snprintf(buf, sizeof buf,
636 " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d cc %d)\r\n",
637 c->self, c->remote_name,
638 c->type, c->remote_id,
639 c->istate, buffer_len(&c->input),
640 c->ostate, buffer_len(&c->output),
641 c->rfd, c->wfd, c->ctl_chan);
642 buffer_append(&buffer, buf, strlen(buf));
643 continue;
644 default:
645 fatal("channel_open_message: bad channel type %d", c->type);
646 /* NOTREACHED */
647 }
648 }
649 buffer_append(&buffer, "\0", 1);
650 cp = xstrdup(buffer_ptr(&buffer));
651 buffer_free(&buffer);
652 return cp;
653 }
654
655 void
656 channel_send_open(int id)
657 {
658 Channel *c = channel_lookup(id);
659
660 if (c == NULL) {
661 logit("channel_send_open: %d: bad id", id);
662 return;
663 }
664 debug2("channel %d: send open", id);
665 packet_start(SSH2_MSG_CHANNEL_OPEN);
666 packet_put_cstring(c->ctype);
667 packet_put_int(c->self);
668 packet_put_int(c->local_window);
669 packet_put_int(c->local_maxpacket);
670 packet_send();
671 }
672
673 void
674 channel_request_start(int id, char *service, int wantconfirm)
675 {
676 Channel *c = channel_lookup(id);
677
678 if (c == NULL) {
679 logit("channel_request_start: %d: unknown channel id", id);
680 return;
681 }
682 debug2("channel %d: request %s confirm %d", id, service, wantconfirm);
683 packet_start(SSH2_MSG_CHANNEL_REQUEST);
684 packet_put_int(c->remote_id);
685 packet_put_cstring(service);
686 packet_put_char(wantconfirm);
687 }
688
689 void
690 channel_register_status_confirm(int id, channel_confirm_cb *cb,
691 channel_confirm_abandon_cb *abandon_cb, void *ctx)
692 {
693 struct channel_confirm *cc;
694 Channel *c;
695
696 if ((c = channel_lookup(id)) == NULL)
697 fatal("channel_register_expect: %d: bad id", id);
698
699 cc = xmalloc(sizeof(*cc));
700 cc->cb = cb;
701 cc->abandon_cb = abandon_cb;
702 cc->ctx = ctx;
703 TAILQ_INSERT_TAIL(&c->status_confirms, cc, entry);
704 }
705
706 void
707 channel_register_open_confirm(int id, channel_open_fn *fn, void *ctx)
708 {
709 Channel *c = channel_lookup(id);
710
711 if (c == NULL) {
712 logit("channel_register_open_confirm: %d: bad id", id);
713 return;
714 }
715 c->open_confirm = fn;
716 c->open_confirm_ctx = ctx;
717 }
718
719 void
720 channel_register_cleanup(int id, channel_callback_fn *fn, int do_close)
721 {
722 Channel *c = channel_by_id(id);
723
724 if (c == NULL) {
725 logit("channel_register_cleanup: %d: bad id", id);
726 return;
727 }
728 c->detach_user = fn;
729 c->detach_close = do_close;
730 }
731
732 void
733 channel_cancel_cleanup(int id)
734 {
735 Channel *c = channel_by_id(id);
736
737 if (c == NULL) {
738 logit("channel_cancel_cleanup: %d: bad id", id);
739 return;
740 }
741 c->detach_user = NULL;
742 c->detach_close = 0;
743 }
744
745 void
746 channel_register_filter(int id, channel_infilter_fn *ifn,
747 channel_outfilter_fn *ofn, channel_filter_cleanup_fn *cfn, void *ctx)
748 {
749 Channel *c = channel_lookup(id);
750
751 if (c == NULL) {
752 logit("channel_register_filter: %d: bad id", id);
753 return;
754 }
755 c->input_filter = ifn;
756 c->output_filter = ofn;
757 c->filter_ctx = ctx;
758 c->filter_cleanup = cfn;
759 }
760
761 void
762 channel_set_fds(int id, int rfd, int wfd, int efd,
763 int extusage, int nonblock, int is_tty, u_int window_max)
764 {
765 Channel *c = channel_lookup(id);
766
767 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
768 fatal("channel_activate for non-larval channel %d.", id);
769 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock, is_tty);
770 c->type = SSH_CHANNEL_OPEN;
771 c->local_window = c->local_window_max = window_max;
772 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
773 packet_put_int(c->remote_id);
774 packet_put_int(c->local_window);
775 packet_send();
776 }
777
778 /*
779 * 'channel_pre*' are called just before select() to add any bits relevant to
780 * channels in the select bitmasks.
781 */
782 /*
783 * 'channel_post*': perform any appropriate operations for channels which
784 * have events pending.
785 */
786 typedef void chan_fn(Channel *c, fd_set *readset, fd_set *writeset);
787 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
788 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
789
790 /* ARGSUSED */
791 static void
792 channel_pre_listener(Channel *c, fd_set *readset, fd_set *writeset)
793 {
794 FD_SET(c->sock, readset);
795 }
796
797 /* ARGSUSED */
798 static void
799 channel_pre_connecting(Channel *c, fd_set *readset, fd_set *writeset)
800 {
801 debug3("channel %d: waiting for connection", c->self);
802 FD_SET(c->sock, writeset);
803 }
804
805 static void
806 channel_pre_open_13(Channel *c, fd_set *readset, fd_set *writeset)
807 {
808 if (buffer_len(&c->input) < packet_get_maxsize())
809 FD_SET(c->sock, readset);
810 if (buffer_len(&c->output) > 0)
811 FD_SET(c->sock, writeset);
812 }
813
814 static void
815 channel_pre_open(Channel *c, fd_set *readset, fd_set *writeset)
816 {
817 u_int limit = compat20 ? c->remote_window : packet_get_maxsize();
818
819 if (c->istate == CHAN_INPUT_OPEN &&
820 limit > 0 &&
821 buffer_len(&c->input) < limit &&
822 buffer_check_alloc(&c->input, CHAN_RBUF))
823 FD_SET(c->rfd, readset);
824 if (c->ostate == CHAN_OUTPUT_OPEN ||
825 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
826 if (buffer_len(&c->output) > 0) {
827 FD_SET(c->wfd, writeset);
828 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
829 if (CHANNEL_EFD_OUTPUT_ACTIVE(c))
830 debug2("channel %d: obuf_empty delayed efd %d/(%d)",
831 c->self, c->efd, buffer_len(&c->extended));
832 else
833 chan_obuf_empty(c);
834 }
835 }
836 /** XXX check close conditions, too */
837 if (compat20 && c->efd != -1 &&
838 !(c->istate == CHAN_INPUT_CLOSED && c->ostate == CHAN_OUTPUT_CLOSED)) {
839 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
840 buffer_len(&c->extended) > 0)
841 FD_SET(c->efd, writeset);
842 else if (c->efd != -1 && !(c->flags & CHAN_EOF_SENT) &&
843 (c->extended_usage == CHAN_EXTENDED_READ ||
844 c->extended_usage == CHAN_EXTENDED_IGNORE) &&
845 buffer_len(&c->extended) < c->remote_window)
846 FD_SET(c->efd, readset);
847 }
848 /* XXX: What about efd? races? */
849 }
850
851 /* ARGSUSED */
852 static void
853 channel_pre_input_draining(Channel *c, fd_set *readset, fd_set *writeset)
854 {
855 if (buffer_len(&c->input) == 0) {
856 packet_start(SSH_MSG_CHANNEL_CLOSE);
857 packet_put_int(c->remote_id);
858 packet_send();
859 c->type = SSH_CHANNEL_CLOSED;
860 debug2("channel %d: closing after input drain.", c->self);
861 }
862 }
863
864 /* ARGSUSED */
865 static void
866 channel_pre_output_draining(Channel *c, fd_set *readset, fd_set *writeset)
867 {
868 if (buffer_len(&c->output) == 0)
869 chan_mark_dead(c);
870 else
871 FD_SET(c->sock, writeset);
872 }
873
874 /*
875 * This is a special state for X11 authentication spoofing. An opened X11
876 * connection (when authentication spoofing is being done) remains in this
877 * state until the first packet has been completely read. The authentication
878 * data in that packet is then substituted by the real data if it matches the
879 * fake data, and the channel is put into normal mode.
880 * XXX All this happens at the client side.
881 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
882 */
883 static int
884 x11_open_helper(Buffer *b)
885 {
886 u_char *ucp;
887 u_int proto_len, data_len;
888
889 /* Check if the fixed size part of the packet is in buffer. */
890 if (buffer_len(b) < 12)
891 return 0;
892
893 /* Parse the lengths of variable-length fields. */
894 ucp = buffer_ptr(b);
895 if (ucp[0] == 0x42) { /* Byte order MSB first. */
896 proto_len = 256 * ucp[6] + ucp[7];
897 data_len = 256 * ucp[8] + ucp[9];
898 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
899 proto_len = ucp[6] + 256 * ucp[7];
900 data_len = ucp[8] + 256 * ucp[9];
901 } else {
902 debug2("Initial X11 packet contains bad byte order byte: 0x%x",
903 ucp[0]);
904 return -1;
905 }
906
907 /* Check if the whole packet is in buffer. */
908 if (buffer_len(b) <
909 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
910 return 0;
911
912 /* Check if authentication protocol matches. */
913 if (proto_len != strlen(x11_saved_proto) ||
914 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
915 debug2("X11 connection uses different authentication protocol.");
916 return -1;
917 }
918 /* Check if authentication data matches our fake data. */
919 if (data_len != x11_fake_data_len ||
920 timingsafe_bcmp(ucp + 12 + ((proto_len + 3) & ~3),
921 x11_fake_data, x11_fake_data_len) != 0) {
922 debug2("X11 auth data does not match fake data.");
923 return -1;
924 }
925 /* Check fake data length */
926 if (x11_fake_data_len != x11_saved_data_len) {
927 error("X11 fake_data_len %d != saved_data_len %d",
928 x11_fake_data_len, x11_saved_data_len);
929 return -1;
930 }
931 /*
932 * Received authentication protocol and data match
933 * our fake data. Substitute the fake data with real
934 * data.
935 */
936 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
937 x11_saved_data, x11_saved_data_len);
938 return 1;
939 }
940
941 static void
942 channel_pre_x11_open_13(Channel *c, fd_set *readset, fd_set *writeset)
943 {
944 int ret = x11_open_helper(&c->output);
945
946 if (ret == 1) {
947 /* Start normal processing for the channel. */
948 c->type = SSH_CHANNEL_OPEN;
949 channel_pre_open_13(c, readset, writeset);
950 } else if (ret == -1) {
951 /*
952 * We have received an X11 connection that has bad
953 * authentication information.
954 */
955 logit("X11 connection rejected because of wrong authentication.");
956 buffer_clear(&c->input);
957 buffer_clear(&c->output);
958 channel_close_fd(&c->sock);
959 c->sock = -1;
960 c->type = SSH_CHANNEL_CLOSED;
961 packet_start(SSH_MSG_CHANNEL_CLOSE);
962 packet_put_int(c->remote_id);
963 packet_send();
964 }
965 }
966
967 static void
968 channel_pre_x11_open(Channel *c, fd_set *readset, fd_set *writeset)
969 {
970 int ret = x11_open_helper(&c->output);
971
972 /* c->force_drain = 1; */
973
974 if (ret == 1) {
975 c->type = SSH_CHANNEL_OPEN;
976 channel_pre_open(c, readset, writeset);
977 } else if (ret == -1) {
978 logit("X11 connection rejected because of wrong authentication.");
979 debug2("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
980 chan_read_failed(c);
981 buffer_clear(&c->input);
982 chan_ibuf_empty(c);
983 buffer_clear(&c->output);
984 /* for proto v1, the peer will send an IEOF */
985 if (compat20)
986 chan_write_failed(c);
987 else
988 c->type = SSH_CHANNEL_OPEN;
989 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
990 }
991 }
992
993 static void
994 channel_pre_mux_client(Channel *c, fd_set *readset, fd_set *writeset)
995 {
996 if (c->istate == CHAN_INPUT_OPEN && !c->mux_pause &&
997 buffer_check_alloc(&c->input, CHAN_RBUF))
998 FD_SET(c->rfd, readset);
999 if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1000 /* clear buffer immediately (discard any partial packet) */
1001 buffer_clear(&c->input);
1002 chan_ibuf_empty(c);
1003 /* Start output drain. XXX just kill chan? */
1004 chan_rcvd_oclose(c);
1005 }
1006 if (c->ostate == CHAN_OUTPUT_OPEN ||
1007 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
1008 if (buffer_len(&c->output) > 0)
1009 FD_SET(c->wfd, writeset);
1010 else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN)
1011 chan_obuf_empty(c);
1012 }
1013 }
1014
1015 /* try to decode a socks4 header */
1016 /* ARGSUSED */
1017 static int
1018 channel_decode_socks4(Channel *c, fd_set *readset, fd_set *writeset)
1019 {
1020 char *p, *host;
1021 u_int len, have, i, found, need;
1022 char username[256];
1023 struct {
1024 u_int8_t version;
1025 u_int8_t command;
1026 u_int16_t dest_port;
1027 struct in_addr dest_addr;
1028 } s4_req, s4_rsp;
1029
1030 debug2("channel %d: decode socks4", c->self);
1031
1032 have = buffer_len(&c->input);
1033 len = sizeof(s4_req);
1034 if (have < len)
1035 return 0;
1036 p = buffer_ptr(&c->input);
1037
1038 need = 1;
1039 /* SOCKS4A uses an invalid IP address 0.0.0.x */
1040 if (p[4] == 0 && p[5] == 0 && p[6] == 0 && p[7] != 0) {
1041 debug2("channel %d: socks4a request", c->self);
1042 /* ... and needs an extra string (the hostname) */
1043 need = 2;
1044 }
1045 /* Check for terminating NUL on the string(s) */
1046 for (found = 0, i = len; i < have; i++) {
1047 if (p[i] == '\0') {
1048 found++;
1049 if (found == need)
1050 break;
1051 }
1052 if (i > 1024) {
1053 /* the peer is probably sending garbage */
1054 debug("channel %d: decode socks4: too long",
1055 c->self);
1056 return -1;
1057 }
1058 }
1059 if (found < need)
1060 return 0;
1061 buffer_get(&c->input, (char *)&s4_req.version, 1);
1062 buffer_get(&c->input, (char *)&s4_req.command, 1);
1063 buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
1064 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
1065 have = buffer_len(&c->input);
1066 p = buffer_ptr(&c->input);
1067 len = strlen(p);
1068 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
1069 len++; /* trailing '\0' */
1070 if (len > have)
1071 fatal("channel %d: decode socks4: len %d > have %d",
1072 c->self, len, have);
1073 strlcpy(username, p, sizeof(username));
1074 buffer_consume(&c->input, len);
1075
1076 if (c->path != NULL) {
1077 xfree(c->path);
1078 c->path = NULL;
1079 }
1080 if (need == 1) { /* SOCKS4: one string */
1081 host = inet_ntoa(s4_req.dest_addr);
1082 c->path = xstrdup(host);
1083 } else { /* SOCKS4A: two strings */
1084 have = buffer_len(&c->input);
1085 p = buffer_ptr(&c->input);
1086 len = strlen(p);
1087 debug2("channel %d: decode socks4a: host %s/%d",
1088 c->self, p, len);
1089 len++; /* trailing '\0' */
1090 if (len > have)
1091 fatal("channel %d: decode socks4a: len %d > have %d",
1092 c->self, len, have);
1093 if (len > NI_MAXHOST) {
1094 error("channel %d: hostname \"%.100s\" too long",
1095 c->self, p);
1096 return -1;
1097 }
1098 c->path = xstrdup(p);
1099 buffer_consume(&c->input, len);
1100 }
1101 c->host_port = ntohs(s4_req.dest_port);
1102
1103 debug2("channel %d: dynamic request: socks4 host %s port %u command %u",
1104 c->self, c->path, c->host_port, s4_req.command);
1105
1106 if (s4_req.command != 1) {
1107 debug("channel %d: cannot handle: %s cn %d",
1108 c->self, need == 1 ? "SOCKS4" : "SOCKS4A", s4_req.command);
1109 return -1;
1110 }
1111 s4_rsp.version = 0; /* vn: 0 for reply */
1112 s4_rsp.command = 90; /* cd: req granted */
1113 s4_rsp.dest_port = 0; /* ignored */
1114 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
1115 buffer_append(&c->output, &s4_rsp, sizeof(s4_rsp));
1116 return 1;
1117 }
1118
1119 /* try to decode a socks5 header */
1120 #define SSH_SOCKS5_AUTHDONE 0x1000
1121 #define SSH_SOCKS5_NOAUTH 0x00
1122 #define SSH_SOCKS5_IPV4 0x01
1123 #define SSH_SOCKS5_DOMAIN 0x03
1124 #define SSH_SOCKS5_IPV6 0x04
1125 #define SSH_SOCKS5_CONNECT 0x01
1126 #define SSH_SOCKS5_SUCCESS 0x00
1127
1128 /* ARGSUSED */
1129 static int
1130 channel_decode_socks5(Channel *c, fd_set *readset, fd_set *writeset)
1131 {
1132 struct {
1133 u_int8_t version;
1134 u_int8_t command;
1135 u_int8_t reserved;
1136 u_int8_t atyp;
1137 } s5_req, s5_rsp;
1138 u_int16_t dest_port;
1139 u_char *p, dest_addr[255+1], ntop[INET6_ADDRSTRLEN];
1140 u_int have, need, i, found, nmethods, addrlen, af;
1141
1142 debug2("channel %d: decode socks5", c->self);
1143 p = buffer_ptr(&c->input);
1144 if (p[0] != 0x05)
1145 return -1;
1146 have = buffer_len(&c->input);
1147 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) {
1148 /* format: ver | nmethods | methods */
1149 if (have < 2)
1150 return 0;
1151 nmethods = p[1];
1152 if (have < nmethods + 2)
1153 return 0;
1154 /* look for method: "NO AUTHENTICATION REQUIRED" */
1155 for (found = 0, i = 2; i < nmethods + 2; i++) {
1156 if (p[i] == SSH_SOCKS5_NOAUTH) {
1157 found = 1;
1158 break;
1159 }
1160 }
1161 if (!found) {
1162 debug("channel %d: method SSH_SOCKS5_NOAUTH not found",
1163 c->self);
1164 return -1;
1165 }
1166 buffer_consume(&c->input, nmethods + 2);
1167 buffer_put_char(&c->output, 0x05); /* version */
1168 buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH); /* method */
1169 FD_SET(c->sock, writeset);
1170 c->flags |= SSH_SOCKS5_AUTHDONE;
1171 debug2("channel %d: socks5 auth done", c->self);
1172 return 0; /* need more */
1173 }
1174 debug2("channel %d: socks5 post auth", c->self);
1175 if (have < sizeof(s5_req)+1)
1176 return 0; /* need more */
1177 memcpy(&s5_req, p, sizeof(s5_req));
1178 if (s5_req.version != 0x05 ||
1179 s5_req.command != SSH_SOCKS5_CONNECT ||
1180 s5_req.reserved != 0x00) {
1181 debug2("channel %d: only socks5 connect supported", c->self);
1182 return -1;
1183 }
1184 switch (s5_req.atyp){
1185 case SSH_SOCKS5_IPV4:
1186 addrlen = 4;
1187 af = AF_INET;
1188 break;
1189 case SSH_SOCKS5_DOMAIN:
1190 addrlen = p[sizeof(s5_req)];
1191 af = -1;
1192 break;
1193 case SSH_SOCKS5_IPV6:
1194 addrlen = 16;
1195 af = AF_INET6;
1196 break;
1197 default:
1198 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp);
1199 return -1;
1200 }
1201 need = sizeof(s5_req) + addrlen + 2;
1202 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1203 need++;
1204 if (have < need)
1205 return 0;
1206 buffer_consume(&c->input, sizeof(s5_req));
1207 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1208 buffer_consume(&c->input, 1); /* host string length */
1209 buffer_get(&c->input, (char *)&dest_addr, addrlen);
1210 buffer_get(&c->input, (char *)&dest_port, 2);
1211 dest_addr[addrlen] = '\0';
1212 if (c->path != NULL) {
1213 xfree(c->path);
1214 c->path = NULL;
1215 }
1216 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) {
1217 if (addrlen >= NI_MAXHOST) {
1218 error("channel %d: dynamic request: socks5 hostname "
1219 "\"%.100s\" too long", c->self, dest_addr);
1220 return -1;
1221 }
1222 c->path = xstrdup(dest_addr);
1223 } else {
1224 if (inet_ntop(af, dest_addr, ntop, sizeof(ntop)) == NULL)
1225 return -1;
1226 c->path = xstrdup(ntop);
1227 }
1228 c->host_port = ntohs(dest_port);
1229
1230 debug2("channel %d: dynamic request: socks5 host %s port %u command %u",
1231 c->self, c->path, c->host_port, s5_req.command);
1232
1233 s5_rsp.version = 0x05;
1234 s5_rsp.command = SSH_SOCKS5_SUCCESS;
1235 s5_rsp.reserved = 0; /* ignored */
1236 s5_rsp.atyp = SSH_SOCKS5_IPV4;
1237 ((struct in_addr *)&dest_addr)->s_addr = INADDR_ANY;
1238 dest_port = 0; /* ignored */
1239
1240 buffer_append(&c->output, &s5_rsp, sizeof(s5_rsp));
1241 buffer_append(&c->output, &dest_addr, sizeof(struct in_addr));
1242 buffer_append(&c->output, &dest_port, sizeof(dest_port));
1243 return 1;
1244 }
1245
1246 Channel *
1247 channel_connect_stdio_fwd(const char *host_to_connect, u_short port_to_connect,
1248 int in, int out)
1249 {
1250 Channel *c;
1251
1252 debug("channel_connect_stdio_fwd %s:%d", host_to_connect,
1253 port_to_connect);
1254
1255 c = channel_new("stdio-forward", SSH_CHANNEL_OPENING, in, out,
1256 -1, CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
1257 0, "stdio-forward", /*nonblock*/0);
1258
1259 c->path = xstrdup(host_to_connect);
1260 c->host_port = port_to_connect;
1261 c->listening_port = 0;
1262 c->force_drain = 1;
1263
1264 channel_register_fds(c, in, out, -1, 0, 1, 0);
1265 port_open_helper(c, "direct-tcpip");
1266
1267 return c;
1268 }
1269
1270 /* dynamic port forwarding */
1271 static void
1272 channel_pre_dynamic(Channel *c, fd_set *readset, fd_set *writeset)
1273 {
1274 u_char *p;
1275 u_int have;
1276 int ret;
1277
1278 have = buffer_len(&c->input);
1279 debug2("channel %d: pre_dynamic: have %d", c->self, have);
1280 /* buffer_dump(&c->input); */
1281 /* check if the fixed size part of the packet is in buffer. */
1282 if (have < 3) {
1283 /* need more */
1284 FD_SET(c->sock, readset);
1285 return;
1286 }
1287 /* try to guess the protocol */
1288 p = buffer_ptr(&c->input);
1289 switch (p[0]) {
1290 case 0x04:
1291 ret = channel_decode_socks4(c, readset, writeset);
1292 break;
1293 case 0x05:
1294 ret = channel_decode_socks5(c, readset, writeset);
1295 break;
1296 default:
1297 ret = -1;
1298 break;
1299 }
1300 if (ret < 0) {
1301 chan_mark_dead(c);
1302 } else if (ret == 0) {
1303 debug2("channel %d: pre_dynamic: need more", c->self);
1304 /* need more */
1305 FD_SET(c->sock, readset);
1306 } else {
1307 /* switch to the next state */
1308 c->type = SSH_CHANNEL_OPENING;
1309 port_open_helper(c, "direct-tcpip");
1310 }
1311 }
1312
1313 /* This is our fake X11 server socket. */
1314 /* ARGSUSED */
1315 static void
1316 channel_post_x11_listener(Channel *c, fd_set *readset, fd_set *writeset)
1317 {
1318 Channel *nc;
1319 struct sockaddr_storage addr;
1320 int newsock;
1321 socklen_t addrlen;
1322 char buf[16384], *remote_ipaddr;
1323 int remote_port;
1324
1325 if (FD_ISSET(c->sock, readset)) {
1326 debug("X11 connection requested.");
1327 addrlen = sizeof(addr);
1328 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1329 if (c->single_connection) {
1330 debug2("single_connection: closing X11 listener.");
1331 channel_close_fd(&c->sock);
1332 chan_mark_dead(c);
1333 }
1334 if (newsock < 0) {
1335 error("accept: %.100s", strerror(errno));
1336 return;
1337 }
1338 set_nodelay(newsock);
1339 remote_ipaddr = get_peer_ipaddr(newsock);
1340 remote_port = get_peer_port(newsock);
1341 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1342 remote_ipaddr, remote_port);
1343
1344 nc = channel_new("accepted x11 socket",
1345 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1346 c->local_window_max, c->local_maxpacket, 0, buf, 1);
1347 if (compat20) {
1348 packet_start(SSH2_MSG_CHANNEL_OPEN);
1349 packet_put_cstring("x11");
1350 packet_put_int(nc->self);
1351 packet_put_int(nc->local_window_max);
1352 packet_put_int(nc->local_maxpacket);
1353 /* originator ipaddr and port */
1354 packet_put_cstring(remote_ipaddr);
1355 if (datafellows & SSH_BUG_X11FWD) {
1356 debug2("ssh2 x11 bug compat mode");
1357 } else {
1358 packet_put_int(remote_port);
1359 }
1360 packet_send();
1361 } else {
1362 packet_start(SSH_SMSG_X11_OPEN);
1363 packet_put_int(nc->self);
1364 if (packet_get_protocol_flags() &
1365 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1366 packet_put_cstring(buf);
1367 packet_send();
1368 }
1369 xfree(remote_ipaddr);
1370 }
1371 }
1372
1373 static void
1374 port_open_helper(Channel *c, char *rtype)
1375 {
1376 int direct;
1377 char buf[1024];
1378 char *remote_ipaddr = get_peer_ipaddr(c->sock);
1379 int remote_port = get_peer_port(c->sock);
1380
1381 if (remote_port == -1) {
1382 /* Fake addr/port to appease peers that validate it (Tectia) */
1383 xfree(remote_ipaddr);
1384 remote_ipaddr = xstrdup("127.0.0.1");
1385 remote_port = 65535;
1386 }
1387
1388 direct = (strcmp(rtype, "direct-tcpip") == 0);
1389
1390 snprintf(buf, sizeof buf,
1391 "%s: listening port %d for %.100s port %d, "
1392 "connect from %.200s port %d",
1393 rtype, c->listening_port, c->path, c->host_port,
1394 remote_ipaddr, remote_port);
1395
1396 xfree(c->remote_name);
1397 c->remote_name = xstrdup(buf);
1398
1399 if (compat20) {
1400 packet_start(SSH2_MSG_CHANNEL_OPEN);
1401 packet_put_cstring(rtype);
1402 packet_put_int(c->self);
1403 packet_put_int(c->local_window_max);
1404 packet_put_int(c->local_maxpacket);
1405 if (direct) {
1406 /* target host, port */
1407 packet_put_cstring(c->path);
1408 packet_put_int(c->host_port);
1409 } else {
1410 /* listen address, port */
1411 packet_put_cstring(c->path);
1412 packet_put_int(c->listening_port);
1413 }
1414 /* originator host and port */
1415 packet_put_cstring(remote_ipaddr);
1416 packet_put_int((u_int)remote_port);
1417 packet_send();
1418 } else {
1419 packet_start(SSH_MSG_PORT_OPEN);
1420 packet_put_int(c->self);
1421 packet_put_cstring(c->path);
1422 packet_put_int(c->host_port);
1423 if (packet_get_protocol_flags() &
1424 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1425 packet_put_cstring(c->remote_name);
1426 packet_send();
1427 }
1428 xfree(remote_ipaddr);
1429 }
1430
1431 static void
1432 channel_set_reuseaddr(int fd)
1433 {
1434 int on = 1;
1435
1436 /*
1437 * Set socket options.
1438 * Allow local port reuse in TIME_WAIT.
1439 */
1440 if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1)
1441 error("setsockopt SO_REUSEADDR fd %d: %s", fd, strerror(errno));
1442 }
1443
1444 /*
1445 * This socket is listening for connections to a forwarded TCP/IP port.
1446 */
1447 /* ARGSUSED */
1448 static void
1449 channel_post_port_listener(Channel *c, fd_set *readset, fd_set *writeset)
1450 {
1451 Channel *nc;
1452 struct sockaddr_storage addr;
1453 int newsock, nextstate;
1454 socklen_t addrlen;
1455 char *rtype;
1456
1457 if (FD_ISSET(c->sock, readset)) {
1458 debug("Connection to port %d forwarding "
1459 "to %.100s port %d requested.",
1460 c->listening_port, c->path, c->host_port);
1461
1462 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1463 nextstate = SSH_CHANNEL_OPENING;
1464 rtype = "forwarded-tcpip";
1465 } else {
1466 if (c->host_port == 0) {
1467 nextstate = SSH_CHANNEL_DYNAMIC;
1468 rtype = "dynamic-tcpip";
1469 } else {
1470 nextstate = SSH_CHANNEL_OPENING;
1471 rtype = "direct-tcpip";
1472 }
1473 }
1474
1475 addrlen = sizeof(addr);
1476 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1477 if (newsock < 0) {
1478 error("accept: %.100s", strerror(errno));
1479 return;
1480 }
1481 set_nodelay(newsock);
1482 nc = channel_new(rtype, nextstate, newsock, newsock, -1,
1483 c->local_window_max, c->local_maxpacket, 0, rtype, 1);
1484 nc->listening_port = c->listening_port;
1485 nc->host_port = c->host_port;
1486 if (c->path != NULL)
1487 nc->path = xstrdup(c->path);
1488
1489 if (nextstate != SSH_CHANNEL_DYNAMIC)
1490 port_open_helper(nc, rtype);
1491 }
1492 }
1493
1494 /*
1495 * This is the authentication agent socket listening for connections from
1496 * clients.
1497 */
1498 /* ARGSUSED */
1499 static void
1500 channel_post_auth_listener(Channel *c, fd_set *readset, fd_set *writeset)
1501 {
1502 Channel *nc;
1503 int newsock;
1504 struct sockaddr_storage addr;
1505 socklen_t addrlen;
1506
1507 if (FD_ISSET(c->sock, readset)) {
1508 addrlen = sizeof(addr);
1509 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1510 if (newsock < 0) {
1511 error("accept from auth socket: %.100s", strerror(errno));
1512 return;
1513 }
1514 nc = channel_new("accepted auth socket",
1515 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1516 c->local_window_max, c->local_maxpacket,
1517 0, "accepted auth socket", 1);
1518 if (compat20) {
1519 packet_start(SSH2_MSG_CHANNEL_OPEN);
1520 packet_put_cstring("auth-agent@openssh.com");
1521 packet_put_int(nc->self);
1522 packet_put_int(c->local_window_max);
1523 packet_put_int(c->local_maxpacket);
1524 } else {
1525 packet_start(SSH_SMSG_AGENT_OPEN);
1526 packet_put_int(nc->self);
1527 }
1528 packet_send();
1529 }
1530 }
1531
1532 /* ARGSUSED */
1533 static void
1534 channel_post_connecting(Channel *c, fd_set *readset, fd_set *writeset)
1535 {
1536 int err = 0, sock;
1537 socklen_t sz = sizeof(err);
1538
1539 if (FD_ISSET(c->sock, writeset)) {
1540 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) {
1541 err = errno;
1542 error("getsockopt SO_ERROR failed");
1543 }
1544 if (err == 0) {
1545 debug("channel %d: connected to %s port %d",
1546 c->self, c->connect_ctx.host, c->connect_ctx.port);
1547 channel_connect_ctx_free(&c->connect_ctx);
1548 c->type = SSH_CHANNEL_OPEN;
1549 if (compat20) {
1550 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1551 packet_put_int(c->remote_id);
1552 packet_put_int(c->self);
1553 packet_put_int(c->local_window);
1554 packet_put_int(c->local_maxpacket);
1555 } else {
1556 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1557 packet_put_int(c->remote_id);
1558 packet_put_int(c->self);
1559 }
1560 } else {
1561 debug("channel %d: connection failed: %s",
1562 c->self, strerror(err));
1563 /* Try next address, if any */
1564 if ((sock = connect_next(&c->connect_ctx)) > 0) {
1565 close(c->sock);
1566 c->sock = c->rfd = c->wfd = sock;
1567 channel_max_fd = channel_find_maxfd();
1568 return;
1569 }
1570 /* Exhausted all addresses */
1571 error("connect_to %.100s port %d: failed.",
1572 c->connect_ctx.host, c->connect_ctx.port);
1573 channel_connect_ctx_free(&c->connect_ctx);
1574 if (compat20) {
1575 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1576 packet_put_int(c->remote_id);
1577 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1578 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1579 packet_put_cstring(strerror(err));
1580 packet_put_cstring("");
1581 }
1582 } else {
1583 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1584 packet_put_int(c->remote_id);
1585 }
1586 chan_mark_dead(c);
1587 }
1588 packet_send();
1589 }
1590 }
1591
1592 /* ARGSUSED */
1593 static int
1594 channel_handle_rfd(Channel *c, fd_set *readset, fd_set *writeset)
1595 {
1596 char buf[CHAN_RBUF];
1597 int len, force;
1598
1599 force = c->isatty && c->detach_close && c->istate != CHAN_INPUT_CLOSED;
1600 if (c->rfd != -1 && (force || FD_ISSET(c->rfd, readset))) {
1601 errno = 0;
1602 len = read(c->rfd, buf, sizeof(buf));
1603 if (len < 0 && (errno == EINTR ||
1604 ((errno == EAGAIN || errno == EWOULDBLOCK) && !force)))
1605 return 1;
1606 #ifndef PTY_ZEROREAD
1607 if (len <= 0) {
1608 #else
1609 if ((!c->isatty && len <= 0) ||
1610 (c->isatty && (len < 0 || (len == 0 && errno != 0)))) {
1611 #endif
1612 debug2("channel %d: read<=0 rfd %d len %d",
1613 c->self, c->rfd, len);
1614 if (c->type != SSH_CHANNEL_OPEN) {
1615 debug2("channel %d: not open", c->self);
1616 chan_mark_dead(c);
1617 return -1;
1618 } else if (compat13) {
1619 buffer_clear(&c->output);
1620 c->type = SSH_CHANNEL_INPUT_DRAINING;
1621 debug2("channel %d: input draining.", c->self);
1622 } else {
1623 chan_read_failed(c);
1624 }
1625 return -1;
1626 }
1627 if (c->input_filter != NULL) {
1628 if (c->input_filter(c, buf, len) == -1) {
1629 debug2("channel %d: filter stops", c->self);
1630 chan_read_failed(c);
1631 }
1632 } else if (c->datagram) {
1633 buffer_put_string(&c->input, buf, len);
1634 } else {
1635 buffer_append(&c->input, buf, len);
1636 }
1637 }
1638 return 1;
1639 }
1640
1641 /* ARGSUSED */
1642 static int
1643 channel_handle_wfd(Channel *c, fd_set *readset, fd_set *writeset)
1644 {
1645 struct termios tio;
1646 u_char *data = NULL, *buf;
1647 u_int dlen, olen = 0;
1648 int len;
1649
1650 /* Send buffered output data to the socket. */
1651 if (c->wfd != -1 &&
1652 FD_ISSET(c->wfd, writeset) &&
1653 buffer_len(&c->output) > 0) {
1654 olen = buffer_len(&c->output);
1655 if (c->output_filter != NULL) {
1656 if ((buf = c->output_filter(c, &data, &dlen)) == NULL) {
1657 debug2("channel %d: filter stops", c->self);
1658 if (c->type != SSH_CHANNEL_OPEN)
1659 chan_mark_dead(c);
1660 else
1661 chan_write_failed(c);
1662 return -1;
1663 }
1664 } else if (c->datagram) {
1665 buf = data = buffer_get_string(&c->output, &dlen);
1666 } else {
1667 buf = data = buffer_ptr(&c->output);
1668 dlen = buffer_len(&c->output);
1669 }
1670
1671 if (c->datagram) {
1672 /* ignore truncated writes, datagrams might get lost */
1673 len = write(c->wfd, buf, dlen);
1674 xfree(data);
1675 if (len < 0 && (errno == EINTR || errno == EAGAIN ||
1676 errno == EWOULDBLOCK))
1677 return 1;
1678 if (len <= 0) {
1679 if (c->type != SSH_CHANNEL_OPEN)
1680 chan_mark_dead(c);
1681 else
1682 chan_write_failed(c);
1683 return -1;
1684 }
1685 goto out;
1686 }
1687 #ifdef _AIX
1688 /* XXX: Later AIX versions can't push as much data to tty */
1689 if (compat20 && c->wfd_isatty)
1690 dlen = MIN(dlen, 8*1024);
1691 #endif
1692
1693 len = write(c->wfd, buf, dlen);
1694 if (len < 0 &&
1695 (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK))
1696 return 1;
1697 if (len <= 0) {
1698 if (c->type != SSH_CHANNEL_OPEN) {
1699 debug2("channel %d: not open", c->self);
1700 chan_mark_dead(c);
1701 return -1;
1702 } else if (compat13) {
1703 buffer_clear(&c->output);
1704 debug2("channel %d: input draining.", c->self);
1705 c->type = SSH_CHANNEL_INPUT_DRAINING;
1706 } else {
1707 chan_write_failed(c);
1708 }
1709 return -1;
1710 }
1711 #ifndef BROKEN_TCGETATTR_ICANON
1712 if (compat20 && c->isatty && dlen >= 1 && buf[0] != '\r') {
1713 if (tcgetattr(c->wfd, &tio) == 0 &&
1714 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1715 /*
1716 * Simulate echo to reduce the impact of
1717 * traffic analysis. We need to match the
1718 * size of a SSH2_MSG_CHANNEL_DATA message
1719 * (4 byte channel id + buf)
1720 */
1721 packet_send_ignore(4 + len);
1722 packet_send();
1723 }
1724 }
1725 #endif
1726 buffer_consume(&c->output, len);
1727 }
1728 out:
1729 if (compat20 && olen > 0)
1730 c->local_consumed += olen - buffer_len(&c->output);
1731 return 1;
1732 }
1733
1734 static int
1735 channel_handle_efd(Channel *c, fd_set *readset, fd_set *writeset)
1736 {
1737 char buf[CHAN_RBUF];
1738 int len;
1739
1740 /** XXX handle drain efd, too */
1741 if (c->efd != -1) {
1742 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1743 FD_ISSET(c->efd, writeset) &&
1744 buffer_len(&c->extended) > 0) {
1745 len = write(c->efd, buffer_ptr(&c->extended),
1746 buffer_len(&c->extended));
1747 debug2("channel %d: written %d to efd %d",
1748 c->self, len, c->efd);
1749 if (len < 0 && (errno == EINTR || errno == EAGAIN ||
1750 errno == EWOULDBLOCK))
1751 return 1;
1752 if (len <= 0) {
1753 debug2("channel %d: closing write-efd %d",
1754 c->self, c->efd);
1755 channel_close_fd(&c->efd);
1756 } else {
1757 buffer_consume(&c->extended, len);
1758 c->local_consumed += len;
1759 }
1760 } else if (c->efd != -1 &&
1761 (c->extended_usage == CHAN_EXTENDED_READ ||
1762 c->extended_usage == CHAN_EXTENDED_IGNORE) &&
1763 (c->detach_close || FD_ISSET(c->efd, readset))) {
1764 len = read(c->efd, buf, sizeof(buf));
1765 debug2("channel %d: read %d from efd %d",
1766 c->self, len, c->efd);
1767 if (len < 0 && (errno == EINTR || ((errno == EAGAIN ||
1768 errno == EWOULDBLOCK) && !c->detach_close)))
1769 return 1;
1770 if (len <= 0) {
1771 debug2("channel %d: closing read-efd %d",
1772 c->self, c->efd);
1773 channel_close_fd(&c->efd);
1774 } else {
1775 if (c->extended_usage == CHAN_EXTENDED_IGNORE) {
1776 debug3("channel %d: discard efd",
1777 c->self);
1778 } else
1779 buffer_append(&c->extended, buf, len);
1780 }
1781 }
1782 }
1783 return 1;
1784 }
1785
1786 static int
1787 channel_check_window(Channel *c)
1788 {
1789 if (c->type == SSH_CHANNEL_OPEN &&
1790 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1791 ((c->local_window_max - c->local_window >
1792 c->local_maxpacket*3) ||
1793 c->local_window < c->local_window_max/2) &&
1794 c->local_consumed > 0) {
1795 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1796 packet_put_int(c->remote_id);
1797 packet_put_int(c->local_consumed);
1798 packet_send();
1799 debug2("channel %d: window %d sent adjust %d",
1800 c->self, c->local_window,
1801 c->local_consumed);
1802 c->local_window += c->local_consumed;
1803 c->local_consumed = 0;
1804 }
1805 return 1;
1806 }
1807
1808 static void
1809 channel_post_open(Channel *c, fd_set *readset, fd_set *writeset)
1810 {
1811 channel_handle_rfd(c, readset, writeset);
1812 channel_handle_wfd(c, readset, writeset);
1813 if (!compat20)
1814 return;
1815 channel_handle_efd(c, readset, writeset);
1816 channel_check_window(c);
1817 }
1818
1819 static u_int
1820 read_mux(Channel *c, u_int need)
1821 {
1822 char buf[CHAN_RBUF];
1823 int len;
1824 u_int rlen;
1825
1826 if (buffer_len(&c->input) < need) {
1827 rlen = need - buffer_len(&c->input);
1828 len = read(c->rfd, buf, MIN(rlen, CHAN_RBUF));
1829 if (len <= 0) {
1830 if (errno != EINTR && errno != EAGAIN) {
1831 debug2("channel %d: ctl read<=0 rfd %d len %d",
1832 c->self, c->rfd, len);
1833 chan_read_failed(c);
1834 return 0;
1835 }
1836 } else
1837 buffer_append(&c->input, buf, len);
1838 }
1839 return buffer_len(&c->input);
1840 }
1841
1842 static void
1843 channel_post_mux_client(Channel *c, fd_set *readset, fd_set *writeset)
1844 {
1845 u_int need;
1846 ssize_t len;
1847
1848 if (!compat20)
1849 fatal("%s: entered with !compat20", __func__);
1850
1851 if (c->rfd != -1 && !c->mux_pause && FD_ISSET(c->rfd, readset) &&
1852 (c->istate == CHAN_INPUT_OPEN ||
1853 c->istate == CHAN_INPUT_WAIT_DRAIN)) {
1854 /*
1855 * Don't not read past the precise end of packets to
1856 * avoid disrupting fd passing.
1857 */
1858 if (read_mux(c, 4) < 4) /* read header */
1859 return;
1860 need = get_u32(buffer_ptr(&c->input));
1861 #define CHANNEL_MUX_MAX_PACKET (256 * 1024)
1862 if (need > CHANNEL_MUX_MAX_PACKET) {
1863 debug2("channel %d: packet too big %u > %u",
1864 c->self, CHANNEL_MUX_MAX_PACKET, need);
1865 chan_rcvd_oclose(c);
1866 return;
1867 }
1868 if (read_mux(c, need + 4) < need + 4) /* read body */
1869 return;
1870 if (c->mux_rcb(c) != 0) {
1871 debug("channel %d: mux_rcb failed", c->self);
1872 chan_mark_dead(c);
1873 return;
1874 }
1875 }
1876
1877 if (c->wfd != -1 && FD_ISSET(c->wfd, writeset) &&
1878 buffer_len(&c->output) > 0) {
1879 len = write(c->wfd, buffer_ptr(&c->output),
1880 buffer_len(&c->output));
1881 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1882 return;
1883 if (len <= 0) {
1884 chan_mark_dead(c);
1885 return;
1886 }
1887 buffer_consume(&c->output, len);
1888 }
1889 }
1890
1891 static void
1892 channel_post_mux_listener(Channel *c, fd_set *readset, fd_set *writeset)
1893 {
1894 Channel *nc;
1895 struct sockaddr_storage addr;
1896 socklen_t addrlen;
1897 int newsock;
1898 uid_t euid;
1899 gid_t egid;
1900
1901 if (!FD_ISSET(c->sock, readset))
1902 return;
1903
1904 debug("multiplexing control connection");
1905
1906 /*
1907 * Accept connection on control socket
1908 */
1909 memset(&addr, 0, sizeof(addr));
1910 addrlen = sizeof(addr);
1911 if ((newsock = accept(c->sock, (struct sockaddr*)&addr,
1912 &addrlen)) == -1) {
1913 error("%s accept: %s", __func__, strerror(errno));
1914 return;
1915 }
1916
1917 if (getpeereid(newsock, &euid, &egid) < 0) {
1918 error("%s getpeereid failed: %s", __func__,
1919 strerror(errno));
1920 close(newsock);
1921 return;
1922 }
1923 if ((euid != 0) && (getuid() != euid)) {
1924 error("multiplex uid mismatch: peer euid %u != uid %u",
1925 (u_int)euid, (u_int)getuid());
1926 close(newsock);
1927 return;
1928 }
1929 nc = channel_new("multiplex client", SSH_CHANNEL_MUX_CLIENT,
1930 newsock, newsock, -1, c->local_window_max,
1931 c->local_maxpacket, 0, "mux-control", 1);
1932 nc->mux_rcb = c->mux_rcb;
1933 debug3("%s: new mux channel %d fd %d", __func__,
1934 nc->self, nc->sock);
1935 /* establish state */
1936 nc->mux_rcb(nc);
1937 /* mux state transitions must not elicit protocol messages */
1938 nc->flags |= CHAN_LOCAL;
1939 }
1940
1941 /* ARGSUSED */
1942 static void
1943 channel_post_output_drain_13(Channel *c, fd_set *readset, fd_set *writeset)
1944 {
1945 int len;
1946
1947 /* Send buffered output data to the socket. */
1948 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1949 len = write(c->sock, buffer_ptr(&c->output),
1950 buffer_len(&c->output));
1951 if (len <= 0)
1952 buffer_clear(&c->output);
1953 else
1954 buffer_consume(&c->output, len);
1955 }
1956 }
1957
1958 static void
1959 channel_handler_init_20(void)
1960 {
1961 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1962 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1963 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1964 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
1965 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1966 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1967 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1968 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1969 channel_pre[SSH_CHANNEL_MUX_LISTENER] = &channel_pre_listener;
1970 channel_pre[SSH_CHANNEL_MUX_CLIENT] = &channel_pre_mux_client;
1971
1972 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1973 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1974 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
1975 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1976 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1977 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1978 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1979 channel_post[SSH_CHANNEL_MUX_LISTENER] = &channel_post_mux_listener;
1980 channel_post[SSH_CHANNEL_MUX_CLIENT] = &channel_post_mux_client;
1981 }
1982
1983 static void
1984 channel_handler_init_13(void)
1985 {
1986 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
1987 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
1988 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1989 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1990 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1991 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
1992 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1993 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1994 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1995
1996 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1997 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1998 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1999 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
2000 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
2001 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
2002 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
2003 }
2004
2005 static void
2006 channel_handler_init_15(void)
2007 {
2008 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
2009 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
2010 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
2011 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
2012 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
2013 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
2014 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
2015
2016 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
2017 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
2018 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
2019 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
2020 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
2021 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
2022 }
2023
2024 static void
2025 channel_handler_init(void)
2026 {
2027 int i;
2028
2029 for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
2030 channel_pre[i] = NULL;
2031 channel_post[i] = NULL;
2032 }
2033 if (compat20)
2034 channel_handler_init_20();
2035 else if (compat13)
2036 channel_handler_init_13();
2037 else
2038 channel_handler_init_15();
2039 }
2040
2041 /* gc dead channels */
2042 static void
2043 channel_garbage_collect(Channel *c)
2044 {
2045 if (c == NULL)
2046 return;
2047 if (c->detach_user != NULL) {
2048 if (!chan_is_dead(c, c->detach_close))
2049 return;
2050 debug2("channel %d: gc: notify user", c->self);
2051 c->detach_user(c->self, NULL);
2052 /* if we still have a callback */
2053 if (c->detach_user != NULL)
2054 return;
2055 debug2("channel %d: gc: user detached", c->self);
2056 }
2057 if (!chan_is_dead(c, 1))
2058 return;
2059 debug2("channel %d: garbage collecting", c->self);
2060 channel_free(c);
2061 }
2062
2063 static void
2064 channel_handler(chan_fn *ftab[], fd_set *readset, fd_set *writeset)
2065 {
2066 static int did_init = 0;
2067 u_int i, oalloc;
2068 Channel *c;
2069
2070 if (!did_init) {
2071 channel_handler_init();
2072 did_init = 1;
2073 }
2074 for (i = 0, oalloc = channels_alloc; i < oalloc; i++) {
2075 c = channels[i];
2076 if (c == NULL)
2077 continue;
2078 if (c->delayed) {
2079 if (ftab == channel_pre)
2080 c->delayed = 0;
2081 else
2082 continue;
2083 }
2084 if (ftab[c->type] != NULL)
2085 (*ftab[c->type])(c, readset, writeset);
2086 channel_garbage_collect(c);
2087 }
2088 }
2089
2090 /*
2091 * Allocate/update select bitmasks and add any bits relevant to channels in
2092 * select bitmasks.
2093 */
2094 void
2095 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
2096 u_int *nallocp, int rekeying)
2097 {
2098 u_int n, sz, nfdset;
2099
2100 n = MAX(*maxfdp, channel_max_fd);
2101
2102 nfdset = howmany(n+1, NFDBITS);
2103 /* Explicitly test here, because xrealloc isn't always called */
2104 if (nfdset && SIZE_T_MAX / nfdset < sizeof(fd_mask))
2105 fatal("channel_prepare_select: max_fd (%d) is too large", n);
2106 sz = nfdset * sizeof(fd_mask);
2107
2108 /* perhaps check sz < nalloc/2 and shrink? */
2109 if (*readsetp == NULL || sz > *nallocp) {
2110 *readsetp = xrealloc(*readsetp, nfdset, sizeof(fd_mask));
2111 *writesetp = xrealloc(*writesetp, nfdset, sizeof(fd_mask));
2112 *nallocp = sz;
2113 }
2114 *maxfdp = n;
2115 memset(*readsetp, 0, sz);
2116 memset(*writesetp, 0, sz);
2117
2118 if (!rekeying)
2119 channel_handler(channel_pre, *readsetp, *writesetp);
2120 }
2121
2122 /*
2123 * After select, perform any appropriate operations for channels which have
2124 * events pending.
2125 */
2126 void
2127 channel_after_select(fd_set *readset, fd_set *writeset)
2128 {
2129 channel_handler(channel_post, readset, writeset);
2130 }
2131
2132
2133 /* If there is data to send to the connection, enqueue some of it now. */
2134 void
2135 channel_output_poll(void)
2136 {
2137 Channel *c;
2138 u_int i, len;
2139
2140 for (i = 0; i < channels_alloc; i++) {
2141 c = channels[i];
2142 if (c == NULL)
2143 continue;
2144
2145 /*
2146 * We are only interested in channels that can have buffered
2147 * incoming data.
2148 */
2149 if (compat13) {
2150 if (c->type != SSH_CHANNEL_OPEN &&
2151 c->type != SSH_CHANNEL_INPUT_DRAINING)
2152 continue;
2153 } else {
2154 if (c->type != SSH_CHANNEL_OPEN)
2155 continue;
2156 }
2157 if (compat20 &&
2158 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
2159 /* XXX is this true? */
2160 debug3("channel %d: will not send data after close", c->self);
2161 continue;
2162 }
2163
2164 /* Get the amount of buffered data for this channel. */
2165 if ((c->istate == CHAN_INPUT_OPEN ||
2166 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
2167 (len = buffer_len(&c->input)) > 0) {
2168 if (c->datagram) {
2169 if (len > 0) {
2170 u_char *data;
2171 u_int dlen;
2172
2173 data = buffer_get_string(&c->input,
2174 &dlen);
2175 if (dlen > c->remote_window ||
2176 dlen > c->remote_maxpacket) {
2177 debug("channel %d: datagram "
2178 "too big for channel",
2179 c->self);
2180 xfree(data);
2181 continue;
2182 }
2183 packet_start(SSH2_MSG_CHANNEL_DATA);
2184 packet_put_int(c->remote_id);
2185 packet_put_string(data, dlen);
2186 packet_send();
2187 c->remote_window -= dlen + 4;
2188 xfree(data);
2189 }
2190 continue;
2191 }
2192 /*
2193 * Send some data for the other side over the secure
2194 * connection.
2195 */
2196 if (compat20) {
2197 if (len > c->remote_window)
2198 len = c->remote_window;
2199 if (len > c->remote_maxpacket)
2200 len = c->remote_maxpacket;
2201 } else {
2202 if (packet_is_interactive()) {
2203 if (len > 1024)
2204 len = 512;
2205 } else {
2206 /* Keep the packets at reasonable size. */
2207 if (len > packet_get_maxsize()/2)
2208 len = packet_get_maxsize()/2;
2209 }
2210 }
2211 if (len > 0) {
2212 packet_start(compat20 ?
2213 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
2214 packet_put_int(c->remote_id);
2215 packet_put_string(buffer_ptr(&c->input), len);
2216 packet_send();
2217 buffer_consume(&c->input, len);
2218 c->remote_window -= len;
2219 }
2220 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
2221 if (compat13)
2222 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
2223 /*
2224 * input-buffer is empty and read-socket shutdown:
2225 * tell peer, that we will not send more data: send IEOF.
2226 * hack for extended data: delay EOF if EFD still in use.
2227 */
2228 if (CHANNEL_EFD_INPUT_ACTIVE(c))
2229 debug2("channel %d: ibuf_empty delayed efd %d/(%d)",
2230 c->self, c->efd, buffer_len(&c->extended));
2231 else
2232 chan_ibuf_empty(c);
2233 }
2234 /* Send extended data, i.e. stderr */
2235 if (compat20 &&
2236 !(c->flags & CHAN_EOF_SENT) &&
2237 c->remote_window > 0 &&
2238 (len = buffer_len(&c->extended)) > 0 &&
2239 c->extended_usage == CHAN_EXTENDED_READ) {
2240 debug2("channel %d: rwin %u elen %u euse %d",
2241 c->self, c->remote_window, buffer_len(&c->extended),
2242 c->extended_usage);
2243 if (len > c->remote_window)
2244 len = c->remote_window;
2245 if (len > c->remote_maxpacket)
2246 len = c->remote_maxpacket;
2247 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
2248 packet_put_int(c->remote_id);
2249 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
2250 packet_put_string(buffer_ptr(&c->extended), len);
2251 packet_send();
2252 buffer_consume(&c->extended, len);
2253 c->remote_window -= len;
2254 debug2("channel %d: sent ext data %d", c->self, len);
2255 }
2256 }
2257 }
2258
2259
2260 /* -- protocol input */
2261
2262 /* ARGSUSED */
2263 void
2264 channel_input_data(int type, u_int32_t seq, void *ctxt)
2265 {
2266 int id;
2267 char *data;
2268 u_int data_len, win_len;
2269 Channel *c;
2270
2271 /* Get the channel number and verify it. */
2272 id = packet_get_int();
2273 c = channel_lookup(id);
2274 if (c == NULL)
2275 packet_disconnect("Received data for nonexistent channel %d.", id);
2276
2277 /* Ignore any data for non-open channels (might happen on close) */
2278 if (c->type != SSH_CHANNEL_OPEN &&
2279 c->type != SSH_CHANNEL_X11_OPEN)
2280 return;
2281
2282 /* Get the data. */
2283 data = packet_get_string_ptr(&data_len);
2284 win_len = data_len;
2285 if (c->datagram)
2286 win_len += 4; /* string length header */
2287
2288 /*
2289 * Ignore data for protocol > 1.3 if output end is no longer open.
2290 * For protocol 2 the sending side is reducing its window as it sends
2291 * data, so we must 'fake' consumption of the data in order to ensure
2292 * that window updates are sent back. Otherwise the connection might
2293 * deadlock.
2294 */
2295 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) {
2296 if (compat20) {
2297 c->local_window -= win_len;
2298 c->local_consumed += win_len;
2299 }
2300 return;
2301 }
2302
2303 if (compat20) {
2304 if (win_len > c->local_maxpacket) {
2305 logit("channel %d: rcvd big packet %d, maxpack %d",
2306 c->self, win_len, c->local_maxpacket);
2307 }
2308 if (win_len > c->local_window) {
2309 logit("channel %d: rcvd too much data %d, win %d",
2310 c->self, win_len, c->local_window);
2311 return;
2312 }
2313 c->local_window -= win_len;
2314 }
2315 if (c->datagram)
2316 buffer_put_string(&c->output, data, data_len);
2317 else
2318 buffer_append(&c->output, data, data_len);
2319 packet_check_eom();
2320 }
2321
2322 /* ARGSUSED */
2323 void
2324 channel_input_extended_data(int type, u_int32_t seq, void *ctxt)
2325 {
2326 int id;
2327 char *data;
2328 u_int data_len, tcode;
2329 Channel *c;
2330
2331 /* Get the channel number and verify it. */
2332 id = packet_get_int();
2333 c = channel_lookup(id);
2334
2335 if (c == NULL)
2336 packet_disconnect("Received extended_data for bad channel %d.", id);
2337 if (c->type != SSH_CHANNEL_OPEN) {
2338 logit("channel %d: ext data for non open", id);
2339 return;
2340 }
2341 if (c->flags & CHAN_EOF_RCVD) {
2342 if (datafellows & SSH_BUG_EXTEOF)
2343 debug("channel %d: accepting ext data after eof", id);
2344 else
2345 packet_disconnect("Received extended_data after EOF "
2346 "on channel %d.", id);
2347 }
2348 tcode = packet_get_int();
2349 if (c->efd == -1 ||
2350 c->extended_usage != CHAN_EXTENDED_WRITE ||
2351 tcode != SSH2_EXTENDED_DATA_STDERR) {
2352 logit("channel %d: bad ext data", c->self);
2353 return;
2354 }
2355 data = packet_get_string(&data_len);
2356 packet_check_eom();
2357 if (data_len > c->local_window) {
2358 logit("channel %d: rcvd too much extended_data %d, win %d",
2359 c->self, data_len, c->local_window);
2360 xfree(data);
2361 return;
2362 }
2363 debug2("channel %d: rcvd ext data %d", c->self, data_len);
2364 c->local_window -= data_len;
2365 buffer_append(&c->extended, data, data_len);
2366 xfree(data);
2367 }
2368
2369 /* ARGSUSED */
2370 void
2371 channel_input_ieof(int type, u_int32_t seq, void *ctxt)
2372 {
2373 int id;
2374 Channel *c;
2375
2376 id = packet_get_int();
2377 packet_check_eom();
2378 c = channel_lookup(id);
2379 if (c == NULL)
2380 packet_disconnect("Received ieof for nonexistent channel %d.", id);
2381 chan_rcvd_ieof(c);
2382
2383 /* XXX force input close */
2384 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) {
2385 debug("channel %d: FORCE input drain", c->self);
2386 c->istate = CHAN_INPUT_WAIT_DRAIN;
2387 if (buffer_len(&c->input) == 0)
2388 chan_ibuf_empty(c);
2389 }
2390
2391 }
2392
2393 /* ARGSUSED */
2394 void
2395 channel_input_close(int type, u_int32_t seq, void *ctxt)
2396 {
2397 int id;
2398 Channel *c;
2399
2400 id = packet_get_int();
2401 packet_check_eom();
2402 c = channel_lookup(id);
2403 if (c == NULL)
2404 packet_disconnect("Received close for nonexistent channel %d.", id);
2405
2406 /*
2407 * Send a confirmation that we have closed the channel and no more
2408 * data is coming for it.
2409 */
2410 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
2411 packet_put_int(c->remote_id);
2412 packet_send();
2413
2414 /*
2415 * If the channel is in closed state, we have sent a close request,
2416 * and the other side will eventually respond with a confirmation.
2417 * Thus, we cannot free the channel here, because then there would be
2418 * no-one to receive the confirmation. The channel gets freed when
2419 * the confirmation arrives.
2420 */
2421 if (c->type != SSH_CHANNEL_CLOSED) {
2422 /*
2423 * Not a closed channel - mark it as draining, which will
2424 * cause it to be freed later.
2425 */
2426 buffer_clear(&c->input);
2427 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
2428 }
2429 }
2430
2431 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
2432 /* ARGSUSED */
2433 void
2434 channel_input_oclose(int type, u_int32_t seq, void *ctxt)
2435 {
2436 int id = packet_get_int();
2437 Channel *c = channel_lookup(id);
2438
2439 packet_check_eom();
2440 if (c == NULL)
2441 packet_disconnect("Received oclose for nonexistent channel %d.", id);
2442 chan_rcvd_oclose(c);
2443 }
2444
2445 /* ARGSUSED */
2446 void
2447 channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt)
2448 {
2449 int id = packet_get_int();
2450 Channel *c = channel_lookup(id);
2451
2452 packet_check_eom();
2453 if (c == NULL)
2454 packet_disconnect("Received close confirmation for "
2455 "out-of-range channel %d.", id);
2456 if (c->type != SSH_CHANNEL_CLOSED)
2457 packet_disconnect("Received close confirmation for "
2458 "non-closed channel %d (type %d).", id, c->type);
2459 channel_free(c);
2460 }
2461
2462 /* ARGSUSED */
2463 void
2464 channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt)
2465 {
2466 int id, remote_id;
2467 Channel *c;
2468
2469 id = packet_get_int();
2470 c = channel_lookup(id);
2471
2472 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2473 packet_disconnect("Received open confirmation for "
2474 "non-opening channel %d.", id);
2475 remote_id = packet_get_int();
2476 /* Record the remote channel number and mark that the channel is now open. */
2477 c->remote_id = remote_id;
2478 c->type = SSH_CHANNEL_OPEN;
2479
2480 if (compat20) {
2481 c->remote_window = packet_get_int();
2482 c->remote_maxpacket = packet_get_int();
2483 if (c->open_confirm) {
2484 debug2("callback start");
2485 c->open_confirm(c->self, 1, c->open_confirm_ctx);
2486 debug2("callback done");
2487 }
2488 debug2("channel %d: open confirm rwindow %u rmax %u", c->self,
2489 c->remote_window, c->remote_maxpacket);
2490 }
2491 packet_check_eom();
2492 }
2493
2494 static char *
2495 reason2txt(int reason)
2496 {
2497 switch (reason) {
2498 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
2499 return "administratively prohibited";
2500 case SSH2_OPEN_CONNECT_FAILED:
2501 return "connect failed";
2502 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
2503 return "unknown channel type";
2504 case SSH2_OPEN_RESOURCE_SHORTAGE:
2505 return "resource shortage";
2506 }
2507 return "unknown reason";
2508 }
2509
2510 /* ARGSUSED */
2511 void
2512 channel_input_open_failure(int type, u_int32_t seq, void *ctxt)
2513 {
2514 int id, reason;
2515 char *msg = NULL, *lang = NULL;
2516 Channel *c;
2517
2518 id = packet_get_int();
2519 c = channel_lookup(id);
2520
2521 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2522 packet_disconnect("Received open failure for "
2523 "non-opening channel %d.", id);
2524 if (compat20) {
2525 reason = packet_get_int();
2526 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
2527 msg = packet_get_string(NULL);
2528 lang = packet_get_string(NULL);
2529 }
2530 logit("channel %d: open failed: %s%s%s", id,
2531 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
2532 if (msg != NULL)
2533 xfree(msg);
2534 if (lang != NULL)
2535 xfree(lang);
2536 if (c->open_confirm) {
2537 debug2("callback start");
2538 c->open_confirm(c->self, 0, c->open_confirm_ctx);
2539 debug2("callback done");
2540 }
2541 }
2542 packet_check_eom();
2543 /* Schedule the channel for cleanup/deletion. */
2544 chan_mark_dead(c);
2545 }
2546
2547 /* ARGSUSED */
2548 void
2549 channel_input_window_adjust(int type, u_int32_t seq, void *ctxt)
2550 {
2551 Channel *c;
2552 int id;
2553 u_int adjust;
2554
2555 if (!compat20)
2556 return;
2557
2558 /* Get the channel number and verify it. */
2559 id = packet_get_int();
2560 c = channel_lookup(id);
2561
2562 if (c == NULL) {
2563 logit("Received window adjust for non-open channel %d.", id);
2564 return;
2565 }
2566 adjust = packet_get_int();
2567 packet_check_eom();
2568 debug2("channel %d: rcvd adjust %u", id, adjust);
2569 c->remote_window += adjust;
2570 }
2571
2572 /* ARGSUSED */
2573 void
2574 channel_input_port_open(int type, u_int32_t seq, void *ctxt)
2575 {
2576 Channel *c = NULL;
2577 u_short host_port;
2578 char *host, *originator_string;
2579 int remote_id;
2580
2581 remote_id = packet_get_int();
2582 host = packet_get_string(NULL);
2583 host_port = packet_get_int();
2584
2585 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2586 originator_string = packet_get_string(NULL);
2587 } else {
2588 originator_string = xstrdup("unknown (remote did not supply name)");
2589 }
2590 packet_check_eom();
2591 c = channel_connect_to(host, host_port,
2592 "connected socket", originator_string);
2593 xfree(originator_string);
2594 xfree(host);
2595 if (c == NULL) {
2596 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2597 packet_put_int(remote_id);
2598 packet_send();
2599 } else
2600 c->remote_id = remote_id;
2601 }
2602
2603 /* ARGSUSED */
2604 void
2605 channel_input_status_confirm(int type, u_int32_t seq, void *ctxt)
2606 {
2607 Channel *c;
2608 struct channel_confirm *cc;
2609 int id;
2610
2611 /* Reset keepalive timeout */
2612 packet_set_alive_timeouts(0);
2613
2614 id = packet_get_int();
2615 packet_check_eom();
2616
2617 debug2("channel_input_status_confirm: type %d id %d", type, id);
2618
2619 if ((c = channel_lookup(id)) == NULL) {
2620 logit("channel_input_status_confirm: %d: unknown", id);
2621 return;
2622 }
2623 ;
2624 if ((cc = TAILQ_FIRST(&c->status_confirms)) == NULL)
2625 return;
2626 cc->cb(type, c, cc->ctx);
2627 TAILQ_REMOVE(&c->status_confirms, cc, entry);
2628 bzero(cc, sizeof(*cc));
2629 xfree(cc);
2630 }
2631
2632 /* -- tcp forwarding */
2633
2634 void
2635 channel_set_af(int af)
2636 {
2637 IPv4or6 = af;
2638 }
2639
2640 static int
2641 channel_setup_fwd_listener(int type, const char *listen_addr,
2642 u_short listen_port, int *allocated_listen_port,
2643 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2644 {
2645 Channel *c;
2646 int sock, r, success = 0, wildcard = 0, is_client;
2647 struct addrinfo hints, *ai, *aitop;
2648 const char *host, *addr;
2649 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2650 in_port_t *lport_p;
2651
2652 host = (type == SSH_CHANNEL_RPORT_LISTENER) ?
2653 listen_addr : host_to_connect;
2654 is_client = (type == SSH_CHANNEL_PORT_LISTENER);
2655
2656 if (host == NULL) {
2657 error("No forward host name.");
2658 return 0;
2659 }
2660 if (strlen(host) >= NI_MAXHOST) {
2661 error("Forward host name too long.");
2662 return 0;
2663 }
2664
2665 /*
2666 * Determine whether or not a port forward listens to loopback,
2667 * specified address or wildcard. On the client, a specified bind
2668 * address will always override gateway_ports. On the server, a
2669 * gateway_ports of 1 (``yes'') will override the client's
2670 * specification and force a wildcard bind, whereas a value of 2
2671 * (``clientspecified'') will bind to whatever address the client
2672 * asked for.
2673 *
2674 * Special-case listen_addrs are:
2675 *
2676 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR
2677 * "" (empty string), "*" -> wildcard v4/v6
2678 * "localhost" -> loopback v4/v6
2679 */
2680 addr = NULL;
2681 if (listen_addr == NULL) {
2682 /* No address specified: default to gateway_ports setting */
2683 if (gateway_ports)
2684 wildcard = 1;
2685 } else if (gateway_ports || is_client) {
2686 if (((datafellows & SSH_OLD_FORWARD_ADDR) &&
2687 strcmp(listen_addr, "0.0.0.0") == 0 && is_client == 0) ||
2688 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 ||
2689 (!is_client && gateway_ports == 1))
2690 wildcard = 1;
2691 else if (strcmp(listen_addr, "localhost") != 0)
2692 addr = listen_addr;
2693 }
2694
2695 debug3("channel_setup_fwd_listener: type %d wildcard %d addr %s",
2696 type, wildcard, (addr == NULL) ? "NULL" : addr);
2697
2698 /*
2699 * getaddrinfo returns a loopback address if the hostname is
2700 * set to NULL and hints.ai_flags is not AI_PASSIVE
2701 */
2702 memset(&hints, 0, sizeof(hints));
2703 hints.ai_family = IPv4or6;
2704 hints.ai_flags = wildcard ? AI_PASSIVE : 0;
2705 hints.ai_socktype = SOCK_STREAM;
2706 snprintf(strport, sizeof strport, "%d", listen_port);
2707 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) {
2708 if (addr == NULL) {
2709 /* This really shouldn't happen */
2710 packet_disconnect("getaddrinfo: fatal error: %s",
2711 ssh_gai_strerror(r));
2712 } else {
2713 error("channel_setup_fwd_listener: "
2714 "getaddrinfo(%.64s): %s", addr,
2715 ssh_gai_strerror(r));
2716 }
2717 return 0;
2718 }
2719 if (allocated_listen_port != NULL)
2720 *allocated_listen_port = 0;
2721 for (ai = aitop; ai; ai = ai->ai_next) {
2722 switch (ai->ai_family) {
2723 case AF_INET:
2724 lport_p = &((struct sockaddr_in *)ai->ai_addr)->
2725 sin_port;
2726 break;
2727 case AF_INET6:
2728 lport_p = &((struct sockaddr_in6 *)ai->ai_addr)->
2729 sin6_port;
2730 break;
2731 default:
2732 continue;
2733 }
2734 /*
2735 * If allocating a port for -R forwards, then use the
2736 * same port for all address families.
2737 */
2738 if (type == SSH_CHANNEL_RPORT_LISTENER && listen_port == 0 &&
2739 allocated_listen_port != NULL && *allocated_listen_port > 0)
2740 *lport_p = htons(*allocated_listen_port);
2741
2742 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2743 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2744 error("channel_setup_fwd_listener: getnameinfo failed");
2745 continue;
2746 }
2747 /* Create a port to listen for the host. */
2748 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2749 if (sock < 0) {
2750 /* this is no error since kernel may not support ipv6 */
2751 verbose("socket: %.100s", strerror(errno));
2752 continue;
2753 }
2754
2755 channel_set_reuseaddr(sock);
2756 if (ai->ai_family == AF_INET6)
2757 sock_set_v6only(sock);
2758
2759 debug("Local forwarding listening on %s port %s.",
2760 ntop, strport);
2761
2762 /* Bind the socket to the address. */
2763 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2764 /* address can be in use ipv6 address is already bound */
2765 if (!ai->ai_next)
2766 error("bind: %.100s", strerror(errno));
2767 else
2768 verbose("bind: %.100s", strerror(errno));
2769
2770 close(sock);
2771 continue;
2772 }
2773 /* Start listening for connections on the socket. */
2774 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2775 error("listen: %.100s", strerror(errno));
2776 close(sock);
2777 continue;
2778 }
2779
2780 /*
2781 * listen_port == 0 requests a dynamically allocated port -
2782 * record what we got.
2783 */
2784 if (type == SSH_CHANNEL_RPORT_LISTENER && listen_port == 0 &&
2785 allocated_listen_port != NULL &&
2786 *allocated_listen_port == 0) {
2787 *allocated_listen_port = get_sock_port(sock, 1);
2788 debug("Allocated listen port %d",
2789 *allocated_listen_port);
2790 }
2791
2792 /* Allocate a channel number for the socket. */
2793 c = channel_new("port listener", type, sock, sock, -1,
2794 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2795 0, "port listener", 1);
2796 c->path = xstrdup(host);
2797 c->host_port = port_to_connect;
2798 c->listening_port = listen_port;
2799 success = 1;
2800 }
2801 if (success == 0)
2802 error("channel_setup_fwd_listener: cannot listen to port: %d",
2803 listen_port);
2804 freeaddrinfo(aitop);
2805 return success;
2806 }
2807
2808 int
2809 channel_cancel_rport_listener(const char *host, u_short port)
2810 {
2811 u_int i;
2812 int found = 0;
2813
2814 for (i = 0; i < channels_alloc; i++) {
2815 Channel *c = channels[i];
2816
2817 if (c != NULL && c->type == SSH_CHANNEL_RPORT_LISTENER &&
2818 strcmp(c->path, host) == 0 && c->listening_port == port) {
2819 debug2("%s: close channel %d", __func__, i);
2820 channel_free(c);
2821 found = 1;
2822 }
2823 }
2824
2825 return (found);
2826 }
2827
2828 /* protocol local port fwd, used by ssh (and sshd in v1) */
2829 int
2830 channel_setup_local_fwd_listener(const char *listen_host, u_short listen_port,
2831 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2832 {
2833 return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER,
2834 listen_host, listen_port, NULL, host_to_connect, port_to_connect,
2835 gateway_ports);
2836 }
2837
2838 /* protocol v2 remote port fwd, used by sshd */
2839 int
2840 channel_setup_remote_fwd_listener(const char *listen_address,
2841 u_short listen_port, int *allocated_listen_port, int gateway_ports)
2842 {
2843 return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER,
2844 listen_address, listen_port, allocated_listen_port,
2845 NULL, 0, gateway_ports);
2846 }
2847
2848 /*
2849 * Initiate forwarding of connections to port "port" on remote host through
2850 * the secure channel to host:port from local side.
2851 */
2852
2853 int
2854 channel_request_remote_forwarding(const char *listen_host, u_short listen_port,
2855 const char *host_to_connect, u_short port_to_connect)
2856 {
2857 int type, success = 0;
2858
2859 /* Send the forward request to the remote side. */
2860 if (compat20) {
2861 const char *address_to_bind;
2862 if (listen_host == NULL) {
2863 if (datafellows & SSH_BUG_RFWD_ADDR)
2864 address_to_bind = "127.0.0.1";
2865 else
2866 address_to_bind = "localhost";
2867 } else if (*listen_host == '\0' ||
2868 strcmp(listen_host, "*") == 0) {
2869 if (datafellows & SSH_BUG_RFWD_ADDR)
2870 address_to_bind = "0.0.0.0";
2871 else
2872 address_to_bind = "";
2873 } else
2874 address_to_bind = listen_host;
2875
2876 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2877 packet_put_cstring("tcpip-forward");
2878 packet_put_char(1); /* boolean: want reply */
2879 packet_put_cstring(address_to_bind);
2880 packet_put_int(listen_port);
2881 packet_send();
2882 packet_write_wait();
2883 /* Assume that server accepts the request */
2884 success = 1;
2885 } else {
2886 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2887 packet_put_int(listen_port);
2888 packet_put_cstring(host_to_connect);
2889 packet_put_int(port_to_connect);
2890 packet_send();
2891 packet_write_wait();
2892
2893 /* Wait for response from the remote side. */
2894 type = packet_read();
2895 switch (type) {
2896 case SSH_SMSG_SUCCESS:
2897 success = 1;
2898 break;
2899 case SSH_SMSG_FAILURE:
2900 break;
2901 default:
2902 /* Unknown packet */
2903 packet_disconnect("Protocol error for port forward request:"
2904 "received packet type %d.", type);
2905 }
2906 }
2907 if (success) {
2908 /* Record that connection to this host/port is permitted. */
2909 permitted_opens = xrealloc(permitted_opens,
2910 num_permitted_opens + 1, sizeof(*permitted_opens));
2911 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2912 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2913 permitted_opens[num_permitted_opens].listen_port = listen_port;
2914 num_permitted_opens++;
2915 }
2916 return (success ? 0 : -1);
2917 }
2918
2919 /*
2920 * Request cancellation of remote forwarding of connection host:port from
2921 * local side.
2922 */
2923 void
2924 channel_request_rforward_cancel(const char *host, u_short port)
2925 {
2926 int i;
2927
2928 if (!compat20)
2929 return;
2930
2931 for (i = 0; i < num_permitted_opens; i++) {
2932 if (permitted_opens[i].host_to_connect != NULL &&
2933 permitted_opens[i].listen_port == port)
2934 break;
2935 }
2936 if (i >= num_permitted_opens) {
2937 debug("%s: requested forward not found", __func__);
2938 return;
2939 }
2940 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2941 packet_put_cstring("cancel-tcpip-forward");
2942 packet_put_char(0);
2943 packet_put_cstring(host == NULL ? "" : host);
2944 packet_put_int(port);
2945 packet_send();
2946
2947 permitted_opens[i].listen_port = 0;
2948 permitted_opens[i].port_to_connect = 0;
2949 xfree(permitted_opens[i].host_to_connect);
2950 permitted_opens[i].host_to_connect = NULL;
2951 }
2952
2953 /*
2954 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
2955 * listening for the port, and sends back a success reply (or disconnect
2956 * message if there was an error).
2957 */
2958 int
2959 channel_input_port_forward_request(int is_root, int gateway_ports)
2960 {
2961 u_short port, host_port;
2962 int success = 0;
2963 char *hostname;
2964
2965 /* Get arguments from the packet. */
2966 port = packet_get_int();
2967 hostname = packet_get_string(NULL);
2968 host_port = packet_get_int();
2969
2970 #ifndef HAVE_CYGWIN
2971 /*
2972 * Check that an unprivileged user is not trying to forward a
2973 * privileged port.
2974 */
2975 if (port < IPPORT_RESERVED && !is_root)
2976 packet_disconnect(
2977 "Requested forwarding of port %d but user is not root.",
2978 port);
2979 if (host_port == 0)
2980 packet_disconnect("Dynamic forwarding denied.");
2981 #endif
2982
2983 /* Initiate forwarding */
2984 success = channel_setup_local_fwd_listener(NULL, port, hostname,
2985 host_port, gateway_ports);
2986
2987 /* Free the argument string. */
2988 xfree(hostname);
2989
2990 return (success ? 0 : -1);
2991 }
2992
2993 /*
2994 * Permits opening to any host/port if permitted_opens[] is empty. This is
2995 * usually called by the server, because the user could connect to any port
2996 * anyway, and the server has no way to know but to trust the client anyway.
2997 */
2998 void
2999 channel_permit_all_opens(void)
3000 {
3001 if (num_permitted_opens == 0)
3002 all_opens_permitted = 1;
3003 }
3004
3005 void
3006 channel_add_permitted_opens(char *host, int port)
3007 {
3008 debug("allow port forwarding to host %s port %d", host, port);
3009
3010 permitted_opens = xrealloc(permitted_opens,
3011 num_permitted_opens + 1, sizeof(*permitted_opens));
3012 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
3013 permitted_opens[num_permitted_opens].port_to_connect = port;
3014 num_permitted_opens++;
3015
3016 all_opens_permitted = 0;
3017 }
3018
3019 int
3020 channel_add_adm_permitted_opens(char *host, int port)
3021 {
3022 debug("config allows port forwarding to host %s port %d", host, port);
3023
3024 permitted_adm_opens = xrealloc(permitted_adm_opens,
3025 num_adm_permitted_opens + 1, sizeof(*permitted_adm_opens));
3026 permitted_adm_opens[num_adm_permitted_opens].host_to_connect
3027 = xstrdup(host);
3028 permitted_adm_opens[num_adm_permitted_opens].port_to_connect = port;
3029 return ++num_adm_permitted_opens;
3030 }
3031
3032 void
3033 channel_clear_permitted_opens(void)
3034 {
3035 int i;
3036
3037 for (i = 0; i < num_permitted_opens; i++)
3038 if (permitted_opens[i].host_to_connect != NULL)
3039 xfree(permitted_opens[i].host_to_connect);
3040 if (num_permitted_opens > 0) {
3041 xfree(permitted_opens);
3042 permitted_opens = NULL;
3043 }
3044 num_permitted_opens = 0;
3045 }
3046
3047 void
3048 channel_clear_adm_permitted_opens(void)
3049 {
3050 int i;
3051
3052 for (i = 0; i < num_adm_permitted_opens; i++)
3053 if (permitted_adm_opens[i].host_to_connect != NULL)
3054 xfree(permitted_adm_opens[i].host_to_connect);
3055 if (num_adm_permitted_opens > 0) {
3056 xfree(permitted_adm_opens);
3057 permitted_adm_opens = NULL;
3058 }
3059 num_adm_permitted_opens = 0;
3060 }
3061
3062 void
3063 channel_print_adm_permitted_opens(void)
3064 {
3065 int i;
3066
3067 printf("permitopen");
3068 if (num_adm_permitted_opens == 0) {
3069 printf(" any\n");
3070 return;
3071 }
3072 for (i = 0; i < num_adm_permitted_opens; i++)
3073 if (permitted_adm_opens[i].host_to_connect != NULL)
3074 printf(" %s:%d", permitted_adm_opens[i].host_to_connect,
3075 permitted_adm_opens[i].port_to_connect);
3076 printf("\n");
3077 }
3078
3079 /* Try to start non-blocking connect to next host in cctx list */
3080 static int
3081 connect_next(struct channel_connect *cctx)
3082 {
3083 int sock, saved_errno;
3084 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
3085
3086 for (; cctx->ai; cctx->ai = cctx->ai->ai_next) {
3087 if (cctx->ai->ai_family != AF_INET &&
3088 cctx->ai->ai_family != AF_INET6)
3089 continue;
3090 if (getnameinfo(cctx->ai->ai_addr, cctx->ai->ai_addrlen,
3091 ntop, sizeof(ntop), strport, sizeof(strport),
3092 NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
3093 error("connect_next: getnameinfo failed");
3094 continue;
3095 }
3096 if ((sock = socket(cctx->ai->ai_family, cctx->ai->ai_socktype,
3097 cctx->ai->ai_protocol)) == -1) {
3098 if (cctx->ai->ai_next == NULL)
3099 error("socket: %.100s", strerror(errno));
3100 else
3101 verbose("socket: %.100s", strerror(errno));
3102 continue;
3103 }
3104 if (set_nonblock(sock) == -1)
3105 fatal("%s: set_nonblock(%d)", __func__, sock);
3106 if (connect(sock, cctx->ai->ai_addr,
3107 cctx->ai->ai_addrlen) == -1 && errno != EINPROGRESS) {
3108 debug("connect_next: host %.100s ([%.100s]:%s): "
3109 "%.100s", cctx->host, ntop, strport,
3110 strerror(errno));
3111 saved_errno = errno;
3112 close(sock);
3113 errno = saved_errno;
3114 continue; /* fail -- try next */
3115 }
3116 debug("connect_next: host %.100s ([%.100s]:%s) "
3117 "in progress, fd=%d", cctx->host, ntop, strport, sock);
3118 cctx->ai = cctx->ai->ai_next;
3119 set_nodelay(sock);
3120 return sock;
3121 }
3122 return -1;
3123 }
3124
3125 static void
3126 channel_connect_ctx_free(struct channel_connect *cctx)
3127 {
3128 xfree(cctx->host);
3129 if (cctx->aitop)
3130 freeaddrinfo(cctx->aitop);
3131 bzero(cctx, sizeof(*cctx));
3132 cctx->host = NULL;
3133 cctx->ai = cctx->aitop = NULL;
3134 }
3135
3136 /* Return CONNECTING channel to remote host, port */
3137 static Channel *
3138 connect_to(const char *host, u_short port, char *ctype, char *rname)
3139 {
3140 struct addrinfo hints;
3141 int gaierr;
3142 int sock = -1;
3143 char strport[NI_MAXSERV];
3144 struct channel_connect cctx;
3145 Channel *c;
3146
3147 memset(&cctx, 0, sizeof(cctx));
3148 memset(&hints, 0, sizeof(hints));
3149 hints.ai_family = IPv4or6;
3150 hints.ai_socktype = SOCK_STREAM;
3151 snprintf(strport, sizeof strport, "%d", port);
3152 if ((gaierr = getaddrinfo(host, strport, &hints, &cctx.aitop)) != 0) {
3153 error("connect_to %.100s: unknown host (%s)", host,
3154 ssh_gai_strerror(gaierr));
3155 return NULL;
3156 }
3157
3158 cctx.host = xstrdup(host);
3159 cctx.port = port;
3160 cctx.ai = cctx.aitop;
3161
3162 if ((sock = connect_next(&cctx)) == -1) {
3163 error("connect to %.100s port %d failed: %s",
3164 host, port, strerror(errno));
3165 channel_connect_ctx_free(&cctx);
3166 return NULL;
3167 }
3168 c = channel_new(ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1,
3169 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1);
3170 c->connect_ctx = cctx;
3171 return c;
3172 }
3173
3174 Channel *
3175 channel_connect_by_listen_address(u_short listen_port, char *ctype, char *rname)
3176 {
3177 int i;
3178
3179 for (i = 0; i < num_permitted_opens; i++) {
3180 if (permitted_opens[i].host_to_connect != NULL &&
3181 permitted_opens[i].listen_port == listen_port) {
3182 return connect_to(
3183 permitted_opens[i].host_to_connect,
3184 permitted_opens[i].port_to_connect, ctype, rname);
3185 }
3186 }
3187 error("WARNING: Server requests forwarding for unknown listen_port %d",
3188 listen_port);
3189 return NULL;
3190 }
3191
3192 /* Check if connecting to that port is permitted and connect. */
3193 Channel *
3194 channel_connect_to(const char *host, u_short port, char *ctype, char *rname)
3195 {
3196 int i, permit, permit_adm = 1;
3197
3198 permit = all_opens_permitted;
3199 if (!permit) {
3200 for (i = 0; i < num_permitted_opens; i++)
3201 if (permitted_opens[i].host_to_connect != NULL &&
3202 permitted_opens[i].port_to_connect == port &&
3203 strcmp(permitted_opens[i].host_to_connect, host) == 0)
3204 permit = 1;
3205 }
3206
3207 if (num_adm_permitted_opens > 0) {
3208 permit_adm = 0;
3209 for (i = 0; i < num_adm_permitted_opens; i++)
3210 if (permitted_adm_opens[i].host_to_connect != NULL &&
3211 permitted_adm_opens[i].port_to_connect == port &&
3212 strcmp(permitted_adm_opens[i].host_to_connect, host)
3213 == 0)
3214 permit_adm = 1;
3215 }
3216
3217 if (!permit || !permit_adm) {
3218 logit("Received request to connect to host %.100s port %d, "
3219 "but the request was denied.", host, port);
3220 return NULL;
3221 }
3222 return connect_to(host, port, ctype, rname);
3223 }
3224
3225 void
3226 channel_send_window_changes(void)
3227 {
3228 u_int i;
3229 struct winsize ws;
3230
3231 for (i = 0; i < channels_alloc; i++) {
3232 if (channels[i] == NULL || !channels[i]->client_tty ||
3233 channels[i]->type != SSH_CHANNEL_OPEN)
3234 continue;
3235 if (ioctl(channels[i]->rfd, TIOCGWINSZ, &ws) < 0)
3236 continue;
3237 channel_request_start(i, "window-change", 0);
3238 packet_put_int((u_int)ws.ws_col);
3239 packet_put_int((u_int)ws.ws_row);
3240 packet_put_int((u_int)ws.ws_xpixel);
3241 packet_put_int((u_int)ws.ws_ypixel);
3242 packet_send();
3243 }
3244 }
3245
3246 /* -- X11 forwarding */
3247
3248 /*
3249 * Creates an internet domain socket for listening for X11 connections.
3250 * Returns 0 and a suitable display number for the DISPLAY variable
3251 * stored in display_numberp , or -1 if an error occurs.
3252 */
3253 int
3254 x11_create_display_inet(int x11_display_offset, int x11_use_localhost,
3255 int single_connection, u_int *display_numberp, int **chanids)
3256 {
3257 Channel *nc = NULL;
3258 int display_number, sock;
3259 u_short port;
3260 struct addrinfo hints, *ai, *aitop;
3261 char strport[NI_MAXSERV];
3262 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
3263
3264 if (chanids == NULL)
3265 return -1;
3266
3267 for (display_number = x11_display_offset;
3268 display_number < MAX_DISPLAYS;
3269 display_number++) {
3270 port = 6000 + display_number;
3271 memset(&hints, 0, sizeof(hints));
3272 hints.ai_family = IPv4or6;
3273 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE;
3274 hints.ai_socktype = SOCK_STREAM;
3275 snprintf(strport, sizeof strport, "%d", port);
3276 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
3277 error("getaddrinfo: %.100s", ssh_gai_strerror(gaierr));
3278 return -1;
3279 }
3280 for (ai = aitop; ai; ai = ai->ai_next) {
3281 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
3282 continue;
3283 sock = socket(ai->ai_family, ai->ai_socktype,
3284 ai->ai_protocol);
3285 if (sock < 0) {
3286 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)
3287 #ifdef EPFNOSUPPORT
3288 && (errno != EPFNOSUPPORT)
3289 #endif
3290 ) {
3291 error("socket: %.100s", strerror(errno));
3292 freeaddrinfo(aitop);
3293 return -1;
3294 } else {
3295 debug("x11_create_display_inet: Socket family %d not supported",
3296 ai->ai_family);
3297 continue;
3298 }
3299 }
3300 if (ai->ai_family == AF_INET6)
3301 sock_set_v6only(sock);
3302 if (x11_use_localhost)
3303 channel_set_reuseaddr(sock);
3304 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
3305 debug2("bind port %d: %.100s", port, strerror(errno));
3306 close(sock);
3307
3308 for (n = 0; n < num_socks; n++) {
3309 close(socks[n]);
3310 }
3311 num_socks = 0;
3312 break;
3313 }
3314 socks[num_socks++] = sock;
3315 if (num_socks == NUM_SOCKS)
3316 break;
3317 }
3318 freeaddrinfo(aitop);
3319 if (num_socks > 0)
3320 break;
3321 }
3322 if (display_number >= MAX_DISPLAYS) {
3323 error("Failed to allocate internet-domain X11 display socket.");
3324 return -1;
3325 }
3326 /* Start listening for connections on the socket. */
3327 for (n = 0; n < num_socks; n++) {
3328 sock = socks[n];
3329 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
3330 error("listen: %.100s", strerror(errno));
3331 close(sock);
3332 return -1;
3333 }
3334 }
3335
3336 /* Allocate a channel for each socket. */
3337 *chanids = xcalloc(num_socks + 1, sizeof(**chanids));
3338 for (n = 0; n < num_socks; n++) {
3339 sock = socks[n];
3340 nc = channel_new("x11 listener",
3341 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
3342 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
3343 0, "X11 inet listener", 1);
3344 nc->single_connection = single_connection;
3345 (*chanids)[n] = nc->self;
3346 }
3347 (*chanids)[n] = -1;
3348
3349 /* Return the display number for the DISPLAY environment variable. */
3350 *display_numberp = display_number;
3351 return (0);
3352 }
3353
3354 static int
3355 connect_local_xsocket_path(const char *pathname)
3356 {
3357 int sock;
3358 struct sockaddr_un addr;
3359
3360 sock = socket(AF_UNIX, SOCK_STREAM, 0);
3361 if (sock < 0)
3362 error("socket: %.100s", strerror(errno));
3363 memset(&addr, 0, sizeof(addr));
3364 addr.sun_family = AF_UNIX;
3365 strlcpy(addr.sun_path, pathname, sizeof addr.sun_path);
3366 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0)
3367 return sock;
3368 close(sock);
3369 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
3370 return -1;
3371 }
3372
3373 static int
3374 connect_local_xsocket(u_int dnr)
3375 {
3376 char buf[1024];
3377 snprintf(buf, sizeof buf, _PATH_UNIX_X, dnr);
3378 return connect_local_xsocket_path(buf);
3379 }
3380
3381 int
3382 x11_connect_display(void)
3383 {
3384 u_int display_number;
3385 const char *display;
3386 char buf[1024], *cp;
3387 struct addrinfo hints, *ai, *aitop;
3388 char strport[NI_MAXSERV];
3389 int gaierr, sock = 0;
3390
3391 /* Try to open a socket for the local X server. */
3392 display = getenv("DISPLAY");
3393 if (!display) {
3394 error("DISPLAY not set.");
3395 return -1;
3396 }
3397 /*
3398 * Now we decode the value of the DISPLAY variable and make a
3399 * connection to the real X server.
3400 */
3401
3402 /* Check if the display is from launchd. */
3403 #ifdef __APPLE__
3404 if (strncmp(display, "/tmp/launch", 11) == 0) {
3405 sock = connect_local_xsocket_path(display);
3406 if (sock < 0)
3407 return -1;
3408
3409 /* OK, we now have a connection to the display. */
3410 return sock;
3411 }
3412 #endif
3413 /*
3414 * Check if it is a unix domain socket. Unix domain displays are in
3415 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
3416 */
3417 if (strncmp(display, "unix:", 5) == 0 ||
3418 display[0] == ':') {
3419 /* Connect to the unix domain socket. */
3420 if (sscanf(strrchr(display, ':') + 1, "%u", &display_number) != 1) {
3421 error("Could not parse display number from DISPLAY: %.100s",
3422 display);
3423 return -1;
3424 }
3425 /* Create a socket. */
3426 sock = connect_local_xsocket(display_number);
3427 if (sock < 0)
3428 return -1;
3429
3430 /* OK, we now have a connection to the display. */
3431 return sock;
3432 }
3433 /*
3434 * Connect to an inet socket. The DISPLAY value is supposedly
3435 * hostname:d[.s], where hostname may also be numeric IP address.
3436 */
3437 strlcpy(buf, display, sizeof(buf));
3438 cp = strchr(buf, ':');
3439 if (!cp) {
3440 error("Could not find ':' in DISPLAY: %.100s", display);
3441 return -1;
3442 }
3443 *cp = 0;
3444 /* buf now contains the host name. But first we parse the display number. */
3445 if (sscanf(cp + 1, "%u", &display_number) != 1) {
3446 error("Could not parse display number from DISPLAY: %.100s",
3447 display);
3448 return -1;
3449 }
3450
3451 /* Look up the host address */
3452 memset(&hints, 0, sizeof(hints));
3453 hints.ai_family = IPv4or6;
3454 hints.ai_socktype = SOCK_STREAM;
3455 snprintf(strport, sizeof strport, "%u", 6000 + display_number);
3456 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
3457 error("%.100s: unknown host. (%s)", buf,
3458 ssh_gai_strerror(gaierr));
3459 return -1;
3460 }
3461 for (ai = aitop; ai; ai = ai->ai_next) {
3462 /* Create a socket. */
3463 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
3464 if (sock < 0) {
3465 debug2("socket: %.100s", strerror(errno));
3466 continue;
3467 }
3468 /* Connect it to the display. */
3469 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
3470 debug2("connect %.100s port %u: %.100s", buf,
3471 6000 + display_number, strerror(errno));
3472 close(sock);
3473 continue;
3474 }
3475 /* Success */
3476 break;
3477 }
3478 freeaddrinfo(aitop);
3479 if (!ai) {
3480 error("connect %.100s port %u: %.100s", buf, 6000 + display_number,
3481 strerror(errno));
3482 return -1;
3483 }
3484 set_nodelay(sock);
3485 return sock;
3486 }
3487
3488 /*
3489 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
3490 * the remote channel number. We should do whatever we want, and respond
3491 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
3492 */
3493
3494 /* ARGSUSED */
3495 void
3496 x11_input_open(int type, u_int32_t seq, void *ctxt)
3497 {
3498 Channel *c = NULL;
3499 int remote_id, sock = 0;
3500 char *remote_host;
3501
3502 debug("Received X11 open request.");
3503
3504 remote_id = packet_get_int();
3505
3506 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
3507 remote_host = packet_get_string(NULL);
3508 } else {
3509 remote_host = xstrdup("unknown (remote did not supply name)");
3510 }
3511 packet_check_eom();
3512
3513 /* Obtain a connection to the real X display. */
3514 sock = x11_connect_display();
3515 if (sock != -1) {
3516 /* Allocate a channel for this connection. */
3517 c = channel_new("connected x11 socket",
3518 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
3519 remote_host, 1);
3520 c->remote_id = remote_id;
3521 c->force_drain = 1;
3522 }
3523 xfree(remote_host);
3524 if (c == NULL) {
3525 /* Send refusal to the remote host. */
3526 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3527 packet_put_int(remote_id);
3528 } else {
3529 /* Send a confirmation to the remote host. */
3530 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
3531 packet_put_int(remote_id);
3532 packet_put_int(c->self);
3533 }
3534 packet_send();
3535 }
3536
3537 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
3538 /* ARGSUSED */
3539 void
3540 deny_input_open(int type, u_int32_t seq, void *ctxt)
3541 {
3542 int rchan = packet_get_int();
3543
3544 switch (type) {
3545 case SSH_SMSG_AGENT_OPEN:
3546 error("Warning: ssh server tried agent forwarding.");
3547 break;
3548 case SSH_SMSG_X11_OPEN:
3549 error("Warning: ssh server tried X11 forwarding.");
3550 break;
3551 default:
3552 error("deny_input_open: type %d", type);
3553 break;
3554 }
3555 error("Warning: this is probably a break-in attempt by a malicious server.");
3556 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3557 packet_put_int(rchan);
3558 packet_send();
3559 }
3560
3561 /*
3562 * Requests forwarding of X11 connections, generates fake authentication
3563 * data, and enables authentication spoofing.
3564 * This should be called in the client only.
3565 */
3566 void
3567 x11_request_forwarding_with_spoofing(int client_session_id, const char *disp,
3568 const char *proto, const char *data)
3569 {
3570 u_int data_len = (u_int) strlen(data) / 2;
3571 u_int i, value;
3572 char *new_data;
3573 int screen_number;
3574 const char *cp;
3575 u_int32_t rnd = 0;
3576
3577 if (x11_saved_display == NULL)
3578 x11_saved_display = xstrdup(disp);
3579 else if (strcmp(disp, x11_saved_display) != 0) {
3580 error("x11_request_forwarding_with_spoofing: different "
3581 "$DISPLAY already forwarded");
3582 return;
3583 }
3584
3585 cp = strchr(disp, ':');
3586 if (cp)
3587 cp = strchr(cp, '.');
3588 if (cp)
3589 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL);
3590 else
3591 screen_number = 0;
3592
3593 if (x11_saved_proto == NULL) {
3594 /* Save protocol name. */
3595 x11_saved_proto = xstrdup(proto);
3596 /*
3597 * Extract real authentication data and generate fake data
3598 * of the same length.
3599 */
3600 x11_saved_data = xmalloc(data_len);
3601 x11_fake_data = xmalloc(data_len);
3602 for (i = 0; i < data_len; i++) {
3603 if (sscanf(data + 2 * i, "%2x", &value) != 1)
3604 fatal("x11_request_forwarding: bad "
3605 "authentication data: %.100s", data);
3606 if (i % 4 == 0)
3607 rnd = arc4random();
3608 x11_saved_data[i] = value;
3609 x11_fake_data[i] = rnd & 0xff;
3610 rnd >>= 8;
3611 }
3612 x11_saved_data_len = data_len;
3613 x11_fake_data_len = data_len;
3614 }
3615
3616 /* Convert the fake data into hex. */
3617 new_data = tohex(x11_fake_data, data_len);
3618
3619 /* Send the request packet. */
3620 if (compat20) {
3621 channel_request_start(client_session_id, "x11-req", 0);
3622 packet_put_char(0); /* XXX bool single connection */
3623 } else {
3624 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
3625 }
3626 packet_put_cstring(proto);
3627 packet_put_cstring(new_data);
3628 packet_put_int(screen_number);
3629 packet_send();
3630 packet_write_wait();
3631 xfree(new_data);
3632 }
3633
3634
3635 /* -- agent forwarding */
3636
3637 /* Sends a message to the server to request authentication fd forwarding. */
3638
3639 void
3640 auth_request_forwarding(void)
3641 {
3642 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
3643 packet_send();
3644 packet_write_wait();
3645 }
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