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- (djm) [openbsd-compat/port-linux.c] Check whether SELinux is enabled
[openssh-git.git] / channels.c
blob6abe2d0127304d0fb413170d1a67a5be23f7320c
1 /* $OpenBSD: channels.c,v 1.310 2010/11/24 01:24:14 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 channel_close_fd(&c->sock);
377 channel_close_fd(&c->rfd);
378 channel_close_fd(&c->wfd);
379 channel_close_fd(&c->efd);
380 }
381
382 /* Free the channel and close its fd/socket. */
383 void
384 channel_free(Channel *c)
385 {
386 char *s;
387 u_int i, n;
388 struct channel_confirm *cc;
389
390 for (n = 0, i = 0; i < channels_alloc; i++)
391 if (channels[i])
392 n++;
393 debug("channel %d: free: %s, nchannels %u", c->self,
394 c->remote_name ? c->remote_name : "???", n);
395
396 s = channel_open_message();
397 debug3("channel %d: status: %s", c->self, s);
398 xfree(s);
399
400 if (c->sock != -1)
401 shutdown(c->sock, SHUT_RDWR);
402 channel_close_fds(c);
403 buffer_free(&c->input);
404 buffer_free(&c->output);
405 buffer_free(&c->extended);
406 if (c->remote_name) {
407 xfree(c->remote_name);
408 c->remote_name = NULL;
409 }
410 if (c->path) {
411 xfree(c->path);
412 c->path = NULL;
413 }
414 while ((cc = TAILQ_FIRST(&c->status_confirms)) != NULL) {
415 if (cc->abandon_cb != NULL)
416 cc->abandon_cb(c, cc->ctx);
417 TAILQ_REMOVE(&c->status_confirms, cc, entry);
418 bzero(cc, sizeof(*cc));
419 xfree(cc);
420 }
421 if (c->filter_cleanup != NULL && c->filter_ctx != NULL)
422 c->filter_cleanup(c->self, c->filter_ctx);
423 channels[c->self] = NULL;
424 xfree(c);
425 }
426
427 void
428 channel_free_all(void)
429 {
430 u_int i;
431
432 for (i = 0; i < channels_alloc; i++)
433 if (channels[i] != NULL)
434 channel_free(channels[i]);
435 }
436
437 /*
438 * Closes the sockets/fds of all channels. This is used to close extra file
439 * descriptors after a fork.
440 */
441 void
442 channel_close_all(void)
443 {
444 u_int i;
445
446 for (i = 0; i < channels_alloc; i++)
447 if (channels[i] != NULL)
448 channel_close_fds(channels[i]);
449 }
450
451 /*
452 * Stop listening to channels.
453 */
454 void
455 channel_stop_listening(void)
456 {
457 u_int i;
458 Channel *c;
459
460 for (i = 0; i < channels_alloc; i++) {
461 c = channels[i];
462 if (c != NULL) {
463 switch (c->type) {
464 case SSH_CHANNEL_AUTH_SOCKET:
465 case SSH_CHANNEL_PORT_LISTENER:
466 case SSH_CHANNEL_RPORT_LISTENER:
467 case SSH_CHANNEL_X11_LISTENER:
468 channel_close_fd(&c->sock);
469 channel_free(c);
470 break;
471 }
472 }
473 }
474 }
475
476 /*
477 * Returns true if no channel has too much buffered data, and false if one or
478 * more channel is overfull.
479 */
480 int
481 channel_not_very_much_buffered_data(void)
482 {
483 u_int i;
484 Channel *c;
485
486 for (i = 0; i < channels_alloc; i++) {
487 c = channels[i];
488 if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
489 #if 0
490 if (!compat20 &&
491 buffer_len(&c->input) > packet_get_maxsize()) {
492 debug2("channel %d: big input buffer %d",
493 c->self, buffer_len(&c->input));
494 return 0;
495 }
496 #endif
497 if (buffer_len(&c->output) > packet_get_maxsize()) {
498 debug2("channel %d: big output buffer %u > %u",
499 c->self, buffer_len(&c->output),
500 packet_get_maxsize());
501 return 0;
502 }
503 }
504 }
505 return 1;
506 }
507
508 /* Returns true if any channel is still open. */
509 int
510 channel_still_open(void)
511 {
512 u_int i;
513 Channel *c;
514
515 for (i = 0; i < channels_alloc; i++) {
516 c = channels[i];
517 if (c == NULL)
518 continue;
519 switch (c->type) {
520 case SSH_CHANNEL_X11_LISTENER:
521 case SSH_CHANNEL_PORT_LISTENER:
522 case SSH_CHANNEL_RPORT_LISTENER:
523 case SSH_CHANNEL_MUX_LISTENER:
524 case SSH_CHANNEL_CLOSED:
525 case SSH_CHANNEL_AUTH_SOCKET:
526 case SSH_CHANNEL_DYNAMIC:
527 case SSH_CHANNEL_CONNECTING:
528 case SSH_CHANNEL_ZOMBIE:
529 continue;
530 case SSH_CHANNEL_LARVAL:
531 if (!compat20)
532 fatal("cannot happen: SSH_CHANNEL_LARVAL");
533 continue;
534 case SSH_CHANNEL_OPENING:
535 case SSH_CHANNEL_OPEN:
536 case SSH_CHANNEL_X11_OPEN:
537 case SSH_CHANNEL_MUX_CLIENT:
538 return 1;
539 case SSH_CHANNEL_INPUT_DRAINING:
540 case SSH_CHANNEL_OUTPUT_DRAINING:
541 if (!compat13)
542 fatal("cannot happen: OUT_DRAIN");
543 return 1;
544 default:
545 fatal("channel_still_open: bad channel type %d", c->type);
546 /* NOTREACHED */
547 }
548 }
549 return 0;
550 }
551
552 /* Returns the id of an open channel suitable for keepaliving */
553 int
554 channel_find_open(void)
555 {
556 u_int i;
557 Channel *c;
558
559 for (i = 0; i < channels_alloc; i++) {
560 c = channels[i];
561 if (c == NULL || c->remote_id < 0)
562 continue;
563 switch (c->type) {
564 case SSH_CHANNEL_CLOSED:
565 case SSH_CHANNEL_DYNAMIC:
566 case SSH_CHANNEL_X11_LISTENER:
567 case SSH_CHANNEL_PORT_LISTENER:
568 case SSH_CHANNEL_RPORT_LISTENER:
569 case SSH_CHANNEL_MUX_LISTENER:
570 case SSH_CHANNEL_MUX_CLIENT:
571 case SSH_CHANNEL_OPENING:
572 case SSH_CHANNEL_CONNECTING:
573 case SSH_CHANNEL_ZOMBIE:
574 continue;
575 case SSH_CHANNEL_LARVAL:
576 case SSH_CHANNEL_AUTH_SOCKET:
577 case SSH_CHANNEL_OPEN:
578 case SSH_CHANNEL_X11_OPEN:
579 return i;
580 case SSH_CHANNEL_INPUT_DRAINING:
581 case SSH_CHANNEL_OUTPUT_DRAINING:
582 if (!compat13)
583 fatal("cannot happen: OUT_DRAIN");
584 return i;
585 default:
586 fatal("channel_find_open: bad channel type %d", c->type);
587 /* NOTREACHED */
588 }
589 }
590 return -1;
591 }
592
593
594 /*
595 * Returns a message describing the currently open forwarded connections,
596 * suitable for sending to the client. The message contains crlf pairs for
597 * newlines.
598 */
599 char *
600 channel_open_message(void)
601 {
602 Buffer buffer;
603 Channel *c;
604 char buf[1024], *cp;
605 u_int i;
606
607 buffer_init(&buffer);
608 snprintf(buf, sizeof buf, "The following connections are open:\r\n");
609 buffer_append(&buffer, buf, strlen(buf));
610 for (i = 0; i < channels_alloc; i++) {
611 c = channels[i];
612 if (c == NULL)
613 continue;
614 switch (c->type) {
615 case SSH_CHANNEL_X11_LISTENER:
616 case SSH_CHANNEL_PORT_LISTENER:
617 case SSH_CHANNEL_RPORT_LISTENER:
618 case SSH_CHANNEL_CLOSED:
619 case SSH_CHANNEL_AUTH_SOCKET:
620 case SSH_CHANNEL_ZOMBIE:
621 case SSH_CHANNEL_MUX_CLIENT:
622 case SSH_CHANNEL_MUX_LISTENER:
623 continue;
624 case SSH_CHANNEL_LARVAL:
625 case SSH_CHANNEL_OPENING:
626 case SSH_CHANNEL_CONNECTING:
627 case SSH_CHANNEL_DYNAMIC:
628 case SSH_CHANNEL_OPEN:
629 case SSH_CHANNEL_X11_OPEN:
630 case SSH_CHANNEL_INPUT_DRAINING:
631 case SSH_CHANNEL_OUTPUT_DRAINING:
632 snprintf(buf, sizeof buf,
633 " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d cc %d)\r\n",
634 c->self, c->remote_name,
635 c->type, c->remote_id,
636 c->istate, buffer_len(&c->input),
637 c->ostate, buffer_len(&c->output),
638 c->rfd, c->wfd, c->ctl_chan);
639 buffer_append(&buffer, buf, strlen(buf));
640 continue;
641 default:
642 fatal("channel_open_message: bad channel type %d", c->type);
643 /* NOTREACHED */
644 }
645 }
646 buffer_append(&buffer, "\0", 1);
647 cp = xstrdup(buffer_ptr(&buffer));
648 buffer_free(&buffer);
649 return cp;
650 }
651
652 void
653 channel_send_open(int id)
654 {
655 Channel *c = channel_lookup(id);
656
657 if (c == NULL) {
658 logit("channel_send_open: %d: bad id", id);
659 return;
660 }
661 debug2("channel %d: send open", id);
662 packet_start(SSH2_MSG_CHANNEL_OPEN);
663 packet_put_cstring(c->ctype);
664 packet_put_int(c->self);
665 packet_put_int(c->local_window);
666 packet_put_int(c->local_maxpacket);
667 packet_send();
668 }
669
670 void
671 channel_request_start(int id, char *service, int wantconfirm)
672 {
673 Channel *c = channel_lookup(id);
674
675 if (c == NULL) {
676 logit("channel_request_start: %d: unknown channel id", id);
677 return;
678 }
679 debug2("channel %d: request %s confirm %d", id, service, wantconfirm);
680 packet_start(SSH2_MSG_CHANNEL_REQUEST);
681 packet_put_int(c->remote_id);
682 packet_put_cstring(service);
683 packet_put_char(wantconfirm);
684 }
685
686 void
687 channel_register_status_confirm(int id, channel_confirm_cb *cb,
688 channel_confirm_abandon_cb *abandon_cb, void *ctx)
689 {
690 struct channel_confirm *cc;
691 Channel *c;
692
693 if ((c = channel_lookup(id)) == NULL)
694 fatal("channel_register_expect: %d: bad id", id);
695
696 cc = xmalloc(sizeof(*cc));
697 cc->cb = cb;
698 cc->abandon_cb = abandon_cb;
699 cc->ctx = ctx;
700 TAILQ_INSERT_TAIL(&c->status_confirms, cc, entry);
701 }
702
703 void
704 channel_register_open_confirm(int id, channel_open_fn *fn, void *ctx)
705 {
706 Channel *c = channel_lookup(id);
707
708 if (c == NULL) {
709 logit("channel_register_open_confirm: %d: bad id", id);
710 return;
711 }
712 c->open_confirm = fn;
713 c->open_confirm_ctx = ctx;
714 }
715
716 void
717 channel_register_cleanup(int id, channel_callback_fn *fn, int do_close)
718 {
719 Channel *c = channel_by_id(id);
720
721 if (c == NULL) {
722 logit("channel_register_cleanup: %d: bad id", id);
723 return;
724 }
725 c->detach_user = fn;
726 c->detach_close = do_close;
727 }
728
729 void
730 channel_cancel_cleanup(int id)
731 {
732 Channel *c = channel_by_id(id);
733
734 if (c == NULL) {
735 logit("channel_cancel_cleanup: %d: bad id", id);
736 return;
737 }
738 c->detach_user = NULL;
739 c->detach_close = 0;
740 }
741
742 void
743 channel_register_filter(int id, channel_infilter_fn *ifn,
744 channel_outfilter_fn *ofn, channel_filter_cleanup_fn *cfn, void *ctx)
745 {
746 Channel *c = channel_lookup(id);
747
748 if (c == NULL) {
749 logit("channel_register_filter: %d: bad id", id);
750 return;
751 }
752 c->input_filter = ifn;
753 c->output_filter = ofn;
754 c->filter_ctx = ctx;
755 c->filter_cleanup = cfn;
756 }
757
758 void
759 channel_set_fds(int id, int rfd, int wfd, int efd,
760 int extusage, int nonblock, int is_tty, u_int window_max)
761 {
762 Channel *c = channel_lookup(id);
763
764 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
765 fatal("channel_activate for non-larval channel %d.", id);
766 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock, is_tty);
767 c->type = SSH_CHANNEL_OPEN;
768 c->local_window = c->local_window_max = window_max;
769 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
770 packet_put_int(c->remote_id);
771 packet_put_int(c->local_window);
772 packet_send();
773 }
774
775 /*
776 * 'channel_pre*' are called just before select() to add any bits relevant to
777 * channels in the select bitmasks.
778 */
779 /*
780 * 'channel_post*': perform any appropriate operations for channels which
781 * have events pending.
782 */
783 typedef void chan_fn(Channel *c, fd_set *readset, fd_set *writeset);
784 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
785 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
786
787 /* ARGSUSED */
788 static void
789 channel_pre_listener(Channel *c, fd_set *readset, fd_set *writeset)
790 {
791 FD_SET(c->sock, readset);
792 }
793
794 /* ARGSUSED */
795 static void
796 channel_pre_connecting(Channel *c, fd_set *readset, fd_set *writeset)
797 {
798 debug3("channel %d: waiting for connection", c->self);
799 FD_SET(c->sock, writeset);
800 }
801
802 static void
803 channel_pre_open_13(Channel *c, fd_set *readset, fd_set *writeset)
804 {
805 if (buffer_len(&c->input) < packet_get_maxsize())
806 FD_SET(c->sock, readset);
807 if (buffer_len(&c->output) > 0)
808 FD_SET(c->sock, writeset);
809 }
810
811 static void
812 channel_pre_open(Channel *c, fd_set *readset, fd_set *writeset)
813 {
814 u_int limit = compat20 ? c->remote_window : packet_get_maxsize();
815
816 if (c->istate == CHAN_INPUT_OPEN &&
817 limit > 0 &&
818 buffer_len(&c->input) < limit &&
819 buffer_check_alloc(&c->input, CHAN_RBUF))
820 FD_SET(c->rfd, readset);
821 if (c->ostate == CHAN_OUTPUT_OPEN ||
822 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
823 if (buffer_len(&c->output) > 0) {
824 FD_SET(c->wfd, writeset);
825 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
826 if (CHANNEL_EFD_OUTPUT_ACTIVE(c))
827 debug2("channel %d: obuf_empty delayed efd %d/(%d)",
828 c->self, c->efd, buffer_len(&c->extended));
829 else
830 chan_obuf_empty(c);
831 }
832 }
833 /** XXX check close conditions, too */
834 if (compat20 && c->efd != -1 &&
835 !(c->istate == CHAN_INPUT_CLOSED && c->ostate == CHAN_OUTPUT_CLOSED)) {
836 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
837 buffer_len(&c->extended) > 0)
838 FD_SET(c->efd, writeset);
839 else if (c->efd != -1 && !(c->flags & CHAN_EOF_SENT) &&
840 (c->extended_usage == CHAN_EXTENDED_READ ||
841 c->extended_usage == CHAN_EXTENDED_IGNORE) &&
842 buffer_len(&c->extended) < c->remote_window)
843 FD_SET(c->efd, readset);
844 }
845 /* XXX: What about efd? races? */
846 }
847
848 /* ARGSUSED */
849 static void
850 channel_pre_input_draining(Channel *c, fd_set *readset, fd_set *writeset)
851 {
852 if (buffer_len(&c->input) == 0) {
853 packet_start(SSH_MSG_CHANNEL_CLOSE);
854 packet_put_int(c->remote_id);
855 packet_send();
856 c->type = SSH_CHANNEL_CLOSED;
857 debug2("channel %d: closing after input drain.", c->self);
858 }
859 }
860
861 /* ARGSUSED */
862 static void
863 channel_pre_output_draining(Channel *c, fd_set *readset, fd_set *writeset)
864 {
865 if (buffer_len(&c->output) == 0)
866 chan_mark_dead(c);
867 else
868 FD_SET(c->sock, writeset);
869 }
870
871 /*
872 * This is a special state for X11 authentication spoofing. An opened X11
873 * connection (when authentication spoofing is being done) remains in this
874 * state until the first packet has been completely read. The authentication
875 * data in that packet is then substituted by the real data if it matches the
876 * fake data, and the channel is put into normal mode.
877 * XXX All this happens at the client side.
878 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
879 */
880 static int
881 x11_open_helper(Buffer *b)
882 {
883 u_char *ucp;
884 u_int proto_len, data_len;
885
886 /* Check if the fixed size part of the packet is in buffer. */
887 if (buffer_len(b) < 12)
888 return 0;
889
890 /* Parse the lengths of variable-length fields. */
891 ucp = buffer_ptr(b);
892 if (ucp[0] == 0x42) { /* Byte order MSB first. */
893 proto_len = 256 * ucp[6] + ucp[7];
894 data_len = 256 * ucp[8] + ucp[9];
895 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
896 proto_len = ucp[6] + 256 * ucp[7];
897 data_len = ucp[8] + 256 * ucp[9];
898 } else {
899 debug2("Initial X11 packet contains bad byte order byte: 0x%x",
900 ucp[0]);
901 return -1;
902 }
903
904 /* Check if the whole packet is in buffer. */
905 if (buffer_len(b) <
906 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
907 return 0;
908
909 /* Check if authentication protocol matches. */
910 if (proto_len != strlen(x11_saved_proto) ||
911 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
912 debug2("X11 connection uses different authentication protocol.");
913 return -1;
914 }
915 /* Check if authentication data matches our fake data. */
916 if (data_len != x11_fake_data_len ||
917 timingsafe_bcmp(ucp + 12 + ((proto_len + 3) & ~3),
918 x11_fake_data, x11_fake_data_len) != 0) {
919 debug2("X11 auth data does not match fake data.");
920 return -1;
921 }
922 /* Check fake data length */
923 if (x11_fake_data_len != x11_saved_data_len) {
924 error("X11 fake_data_len %d != saved_data_len %d",
925 x11_fake_data_len, x11_saved_data_len);
926 return -1;
927 }
928 /*
929 * Received authentication protocol and data match
930 * our fake data. Substitute the fake data with real
931 * data.
932 */
933 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
934 x11_saved_data, x11_saved_data_len);
935 return 1;
936 }
937
938 static void
939 channel_pre_x11_open_13(Channel *c, fd_set *readset, fd_set *writeset)
940 {
941 int ret = x11_open_helper(&c->output);
942
943 if (ret == 1) {
944 /* Start normal processing for the channel. */
945 c->type = SSH_CHANNEL_OPEN;
946 channel_pre_open_13(c, readset, writeset);
947 } else if (ret == -1) {
948 /*
949 * We have received an X11 connection that has bad
950 * authentication information.
951 */
952 logit("X11 connection rejected because of wrong authentication.");
953 buffer_clear(&c->input);
954 buffer_clear(&c->output);
955 channel_close_fd(&c->sock);
956 c->sock = -1;
957 c->type = SSH_CHANNEL_CLOSED;
958 packet_start(SSH_MSG_CHANNEL_CLOSE);
959 packet_put_int(c->remote_id);
960 packet_send();
961 }
962 }
963
964 static void
965 channel_pre_x11_open(Channel *c, fd_set *readset, fd_set *writeset)
966 {
967 int ret = x11_open_helper(&c->output);
968
969 /* c->force_drain = 1; */
970
971 if (ret == 1) {
972 c->type = SSH_CHANNEL_OPEN;
973 channel_pre_open(c, readset, writeset);
974 } else if (ret == -1) {
975 logit("X11 connection rejected because of wrong authentication.");
976 debug2("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
977 chan_read_failed(c);
978 buffer_clear(&c->input);
979 chan_ibuf_empty(c);
980 buffer_clear(&c->output);
981 /* for proto v1, the peer will send an IEOF */
982 if (compat20)
983 chan_write_failed(c);
984 else
985 c->type = SSH_CHANNEL_OPEN;
986 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
987 }
988 }
989
990 static void
991 channel_pre_mux_client(Channel *c, fd_set *readset, fd_set *writeset)
992 {
993 if (c->istate == CHAN_INPUT_OPEN && !c->mux_pause &&
994 buffer_check_alloc(&c->input, CHAN_RBUF))
995 FD_SET(c->rfd, readset);
996 if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
997 /* clear buffer immediately (discard any partial packet) */
998 buffer_clear(&c->input);
999 chan_ibuf_empty(c);
1000 /* Start output drain. XXX just kill chan? */
1001 chan_rcvd_oclose(c);
1002 }
1003 if (c->ostate == CHAN_OUTPUT_OPEN ||
1004 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
1005 if (buffer_len(&c->output) > 0)
1006 FD_SET(c->wfd, writeset);
1007 else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN)
1008 chan_obuf_empty(c);
1009 }
1010 }
1011
1012 /* try to decode a socks4 header */
1013 /* ARGSUSED */
1014 static int
1015 channel_decode_socks4(Channel *c, fd_set *readset, fd_set *writeset)
1016 {
1017 char *p, *host;
1018 u_int len, have, i, found, need;
1019 char username[256];
1020 struct {
1021 u_int8_t version;
1022 u_int8_t command;
1023 u_int16_t dest_port;
1024 struct in_addr dest_addr;
1025 } s4_req, s4_rsp;
1026
1027 debug2("channel %d: decode socks4", c->self);
1028
1029 have = buffer_len(&c->input);
1030 len = sizeof(s4_req);
1031 if (have < len)
1032 return 0;
1033 p = buffer_ptr(&c->input);
1034
1035 need = 1;
1036 /* SOCKS4A uses an invalid IP address 0.0.0.x */
1037 if (p[4] == 0 && p[5] == 0 && p[6] == 0 && p[7] != 0) {
1038 debug2("channel %d: socks4a request", c->self);
1039 /* ... and needs an extra string (the hostname) */
1040 need = 2;
1041 }
1042 /* Check for terminating NUL on the string(s) */
1043 for (found = 0, i = len; i < have; i++) {
1044 if (p[i] == '\0') {
1045 found++;
1046 if (found == need)
1047 break;
1048 }
1049 if (i > 1024) {
1050 /* the peer is probably sending garbage */
1051 debug("channel %d: decode socks4: too long",
1052 c->self);
1053 return -1;
1054 }
1055 }
1056 if (found < need)
1057 return 0;
1058 buffer_get(&c->input, (char *)&s4_req.version, 1);
1059 buffer_get(&c->input, (char *)&s4_req.command, 1);
1060 buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
1061 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
1062 have = buffer_len(&c->input);
1063 p = buffer_ptr(&c->input);
1064 len = strlen(p);
1065 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
1066 len++; /* trailing '\0' */
1067 if (len > have)
1068 fatal("channel %d: decode socks4: len %d > have %d",
1069 c->self, len, have);
1070 strlcpy(username, p, sizeof(username));
1071 buffer_consume(&c->input, len);
1072
1073 if (c->path != NULL) {
1074 xfree(c->path);
1075 c->path = NULL;
1076 }
1077 if (need == 1) { /* SOCKS4: one string */
1078 host = inet_ntoa(s4_req.dest_addr);
1079 c->path = xstrdup(host);
1080 } else { /* SOCKS4A: two strings */
1081 have = buffer_len(&c->input);
1082 p = buffer_ptr(&c->input);
1083 len = strlen(p);
1084 debug2("channel %d: decode socks4a: host %s/%d",
1085 c->self, p, len);
1086 len++; /* trailing '\0' */
1087 if (len > have)
1088 fatal("channel %d: decode socks4a: len %d > have %d",
1089 c->self, len, have);
1090 if (len > NI_MAXHOST) {
1091 error("channel %d: hostname \"%.100s\" too long",
1092 c->self, p);
1093 return -1;
1094 }
1095 c->path = xstrdup(p);
1096 buffer_consume(&c->input, len);
1097 }
1098 c->host_port = ntohs(s4_req.dest_port);
1099
1100 debug2("channel %d: dynamic request: socks4 host %s port %u command %u",
1101 c->self, c->path, c->host_port, s4_req.command);
1102
1103 if (s4_req.command != 1) {
1104 debug("channel %d: cannot handle: %s cn %d",
1105 c->self, need == 1 ? "SOCKS4" : "SOCKS4A", s4_req.command);
1106 return -1;
1107 }
1108 s4_rsp.version = 0; /* vn: 0 for reply */
1109 s4_rsp.command = 90; /* cd: req granted */
1110 s4_rsp.dest_port = 0; /* ignored */
1111 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
1112 buffer_append(&c->output, &s4_rsp, sizeof(s4_rsp));
1113 return 1;
1114 }
1115
1116 /* try to decode a socks5 header */
1117 #define SSH_SOCKS5_AUTHDONE 0x1000
1118 #define SSH_SOCKS5_NOAUTH 0x00
1119 #define SSH_SOCKS5_IPV4 0x01
1120 #define SSH_SOCKS5_DOMAIN 0x03
1121 #define SSH_SOCKS5_IPV6 0x04
1122 #define SSH_SOCKS5_CONNECT 0x01
1123 #define SSH_SOCKS5_SUCCESS 0x00
1124
1125 /* ARGSUSED */
1126 static int
1127 channel_decode_socks5(Channel *c, fd_set *readset, fd_set *writeset)
1128 {
1129 struct {
1130 u_int8_t version;
1131 u_int8_t command;
1132 u_int8_t reserved;
1133 u_int8_t atyp;
1134 } s5_req, s5_rsp;
1135 u_int16_t dest_port;
1136 u_char *p, dest_addr[255+1], ntop[INET6_ADDRSTRLEN];
1137 u_int have, need, i, found, nmethods, addrlen, af;
1138
1139 debug2("channel %d: decode socks5", c->self);
1140 p = buffer_ptr(&c->input);
1141 if (p[0] != 0x05)
1142 return -1;
1143 have = buffer_len(&c->input);
1144 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) {
1145 /* format: ver | nmethods | methods */
1146 if (have < 2)
1147 return 0;
1148 nmethods = p[1];
1149 if (have < nmethods + 2)
1150 return 0;
1151 /* look for method: "NO AUTHENTICATION REQUIRED" */
1152 for (found = 0, i = 2; i < nmethods + 2; i++) {
1153 if (p[i] == SSH_SOCKS5_NOAUTH) {
1154 found = 1;
1155 break;
1156 }
1157 }
1158 if (!found) {
1159 debug("channel %d: method SSH_SOCKS5_NOAUTH not found",
1160 c->self);
1161 return -1;
1162 }
1163 buffer_consume(&c->input, nmethods + 2);
1164 buffer_put_char(&c->output, 0x05); /* version */
1165 buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH); /* method */
1166 FD_SET(c->sock, writeset);
1167 c->flags |= SSH_SOCKS5_AUTHDONE;
1168 debug2("channel %d: socks5 auth done", c->self);
1169 return 0; /* need more */
1170 }
1171 debug2("channel %d: socks5 post auth", c->self);
1172 if (have < sizeof(s5_req)+1)
1173 return 0; /* need more */
1174 memcpy(&s5_req, p, sizeof(s5_req));
1175 if (s5_req.version != 0x05 ||
1176 s5_req.command != SSH_SOCKS5_CONNECT ||
1177 s5_req.reserved != 0x00) {
1178 debug2("channel %d: only socks5 connect supported", c->self);
1179 return -1;
1180 }
1181 switch (s5_req.atyp){
1182 case SSH_SOCKS5_IPV4:
1183 addrlen = 4;
1184 af = AF_INET;
1185 break;
1186 case SSH_SOCKS5_DOMAIN:
1187 addrlen = p[sizeof(s5_req)];
1188 af = -1;
1189 break;
1190 case SSH_SOCKS5_IPV6:
1191 addrlen = 16;
1192 af = AF_INET6;
1193 break;
1194 default:
1195 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp);
1196 return -1;
1197 }
1198 need = sizeof(s5_req) + addrlen + 2;
1199 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1200 need++;
1201 if (have < need)
1202 return 0;
1203 buffer_consume(&c->input, sizeof(s5_req));
1204 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1205 buffer_consume(&c->input, 1); /* host string length */
1206 buffer_get(&c->input, (char *)&dest_addr, addrlen);
1207 buffer_get(&c->input, (char *)&dest_port, 2);
1208 dest_addr[addrlen] = '\0';
1209 if (c->path != NULL) {
1210 xfree(c->path);
1211 c->path = NULL;
1212 }
1213 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) {
1214 if (addrlen >= NI_MAXHOST) {
1215 error("channel %d: dynamic request: socks5 hostname "
1216 "\"%.100s\" too long", c->self, dest_addr);
1217 return -1;
1218 }
1219 c->path = xstrdup(dest_addr);
1220 } else {
1221 if (inet_ntop(af, dest_addr, ntop, sizeof(ntop)) == NULL)
1222 return -1;
1223 c->path = xstrdup(ntop);
1224 }
1225 c->host_port = ntohs(dest_port);
1226
1227 debug2("channel %d: dynamic request: socks5 host %s port %u command %u",
1228 c->self, c->path, c->host_port, s5_req.command);
1229
1230 s5_rsp.version = 0x05;
1231 s5_rsp.command = SSH_SOCKS5_SUCCESS;
1232 s5_rsp.reserved = 0; /* ignored */
1233 s5_rsp.atyp = SSH_SOCKS5_IPV4;
1234 ((struct in_addr *)&dest_addr)->s_addr = INADDR_ANY;
1235 dest_port = 0; /* ignored */
1236
1237 buffer_append(&c->output, &s5_rsp, sizeof(s5_rsp));
1238 buffer_append(&c->output, &dest_addr, sizeof(struct in_addr));
1239 buffer_append(&c->output, &dest_port, sizeof(dest_port));
1240 return 1;
1241 }
1242
1243 Channel *
1244 channel_connect_stdio_fwd(const char *host_to_connect, u_short port_to_connect,
1245 int in, int out)
1246 {
1247 Channel *c;
1248
1249 debug("channel_connect_stdio_fwd %s:%d", host_to_connect,
1250 port_to_connect);
1251
1252 c = channel_new("stdio-forward", SSH_CHANNEL_OPENING, in, out,
1253 -1, CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
1254 0, "stdio-forward", /*nonblock*/0);
1255
1256 c->path = xstrdup(host_to_connect);
1257 c->host_port = port_to_connect;
1258 c->listening_port = 0;
1259 c->force_drain = 1;
1260
1261 channel_register_fds(c, in, out, -1, 0, 1, 0);
1262 port_open_helper(c, "direct-tcpip");
1263
1264 return c;
1265 }
1266
1267 /* dynamic port forwarding */
1268 static void
1269 channel_pre_dynamic(Channel *c, fd_set *readset, fd_set *writeset)
1270 {
1271 u_char *p;
1272 u_int have;
1273 int ret;
1274
1275 have = buffer_len(&c->input);
1276 debug2("channel %d: pre_dynamic: have %d", c->self, have);
1277 /* buffer_dump(&c->input); */
1278 /* check if the fixed size part of the packet is in buffer. */
1279 if (have < 3) {
1280 /* need more */
1281 FD_SET(c->sock, readset);
1282 return;
1283 }
1284 /* try to guess the protocol */
1285 p = buffer_ptr(&c->input);
1286 switch (p[0]) {
1287 case 0x04:
1288 ret = channel_decode_socks4(c, readset, writeset);
1289 break;
1290 case 0x05:
1291 ret = channel_decode_socks5(c, readset, writeset);
1292 break;
1293 default:
1294 ret = -1;
1295 break;
1296 }
1297 if (ret < 0) {
1298 chan_mark_dead(c);
1299 } else if (ret == 0) {
1300 debug2("channel %d: pre_dynamic: need more", c->self);
1301 /* need more */
1302 FD_SET(c->sock, readset);
1303 } else {
1304 /* switch to the next state */
1305 c->type = SSH_CHANNEL_OPENING;
1306 port_open_helper(c, "direct-tcpip");
1307 }
1308 }
1309
1310 /* This is our fake X11 server socket. */
1311 /* ARGSUSED */
1312 static void
1313 channel_post_x11_listener(Channel *c, fd_set *readset, fd_set *writeset)
1314 {
1315 Channel *nc;
1316 struct sockaddr_storage addr;
1317 int newsock;
1318 socklen_t addrlen;
1319 char buf[16384], *remote_ipaddr;
1320 int remote_port;
1321
1322 if (FD_ISSET(c->sock, readset)) {
1323 debug("X11 connection requested.");
1324 addrlen = sizeof(addr);
1325 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1326 if (c->single_connection) {
1327 debug2("single_connection: closing X11 listener.");
1328 channel_close_fd(&c->sock);
1329 chan_mark_dead(c);
1330 }
1331 if (newsock < 0) {
1332 error("accept: %.100s", strerror(errno));
1333 return;
1334 }
1335 set_nodelay(newsock);
1336 remote_ipaddr = get_peer_ipaddr(newsock);
1337 remote_port = get_peer_port(newsock);
1338 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1339 remote_ipaddr, remote_port);
1340
1341 nc = channel_new("accepted x11 socket",
1342 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1343 c->local_window_max, c->local_maxpacket, 0, buf, 1);
1344 if (compat20) {
1345 packet_start(SSH2_MSG_CHANNEL_OPEN);
1346 packet_put_cstring("x11");
1347 packet_put_int(nc->self);
1348 packet_put_int(nc->local_window_max);
1349 packet_put_int(nc->local_maxpacket);
1350 /* originator ipaddr and port */
1351 packet_put_cstring(remote_ipaddr);
1352 if (datafellows & SSH_BUG_X11FWD) {
1353 debug2("ssh2 x11 bug compat mode");
1354 } else {
1355 packet_put_int(remote_port);
1356 }
1357 packet_send();
1358 } else {
1359 packet_start(SSH_SMSG_X11_OPEN);
1360 packet_put_int(nc->self);
1361 if (packet_get_protocol_flags() &
1362 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1363 packet_put_cstring(buf);
1364 packet_send();
1365 }
1366 xfree(remote_ipaddr);
1367 }
1368 }
1369
1370 static void
1371 port_open_helper(Channel *c, char *rtype)
1372 {
1373 int direct;
1374 char buf[1024];
1375 char *remote_ipaddr = get_peer_ipaddr(c->sock);
1376 int remote_port = get_peer_port(c->sock);
1377
1378 if (remote_port == -1) {
1379 /* Fake addr/port to appease peers that validate it (Tectia) */
1380 xfree(remote_ipaddr);
1381 remote_ipaddr = xstrdup("127.0.0.1");
1382 remote_port = 65535;
1383 }
1384
1385 direct = (strcmp(rtype, "direct-tcpip") == 0);
1386
1387 snprintf(buf, sizeof buf,
1388 "%s: listening port %d for %.100s port %d, "
1389 "connect from %.200s port %d",
1390 rtype, c->listening_port, c->path, c->host_port,
1391 remote_ipaddr, remote_port);
1392
1393 xfree(c->remote_name);
1394 c->remote_name = xstrdup(buf);
1395
1396 if (compat20) {
1397 packet_start(SSH2_MSG_CHANNEL_OPEN);
1398 packet_put_cstring(rtype);
1399 packet_put_int(c->self);
1400 packet_put_int(c->local_window_max);
1401 packet_put_int(c->local_maxpacket);
1402 if (direct) {
1403 /* target host, port */
1404 packet_put_cstring(c->path);
1405 packet_put_int(c->host_port);
1406 } else {
1407 /* listen address, port */
1408 packet_put_cstring(c->path);
1409 packet_put_int(c->listening_port);
1410 }
1411 /* originator host and port */
1412 packet_put_cstring(remote_ipaddr);
1413 packet_put_int((u_int)remote_port);
1414 packet_send();
1415 } else {
1416 packet_start(SSH_MSG_PORT_OPEN);
1417 packet_put_int(c->self);
1418 packet_put_cstring(c->path);
1419 packet_put_int(c->host_port);
1420 if (packet_get_protocol_flags() &
1421 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1422 packet_put_cstring(c->remote_name);
1423 packet_send();
1424 }
1425 xfree(remote_ipaddr);
1426 }
1427
1428 static void
1429 channel_set_reuseaddr(int fd)
1430 {
1431 int on = 1;
1432
1433 /*
1434 * Set socket options.
1435 * Allow local port reuse in TIME_WAIT.
1436 */
1437 if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1)
1438 error("setsockopt SO_REUSEADDR fd %d: %s", fd, strerror(errno));
1439 }
1440
1441 /*
1442 * This socket is listening for connections to a forwarded TCP/IP port.
1443 */
1444 /* ARGSUSED */
1445 static void
1446 channel_post_port_listener(Channel *c, fd_set *readset, fd_set *writeset)
1447 {
1448 Channel *nc;
1449 struct sockaddr_storage addr;
1450 int newsock, nextstate;
1451 socklen_t addrlen;
1452 char *rtype;
1453
1454 if (FD_ISSET(c->sock, readset)) {
1455 debug("Connection to port %d forwarding "
1456 "to %.100s port %d requested.",
1457 c->listening_port, c->path, c->host_port);
1458
1459 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1460 nextstate = SSH_CHANNEL_OPENING;
1461 rtype = "forwarded-tcpip";
1462 } else {
1463 if (c->host_port == 0) {
1464 nextstate = SSH_CHANNEL_DYNAMIC;
1465 rtype = "dynamic-tcpip";
1466 } else {
1467 nextstate = SSH_CHANNEL_OPENING;
1468 rtype = "direct-tcpip";
1469 }
1470 }
1471
1472 addrlen = sizeof(addr);
1473 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1474 if (newsock < 0) {
1475 error("accept: %.100s", strerror(errno));
1476 return;
1477 }
1478 set_nodelay(newsock);
1479 nc = channel_new(rtype, nextstate, newsock, newsock, -1,
1480 c->local_window_max, c->local_maxpacket, 0, rtype, 1);
1481 nc->listening_port = c->listening_port;
1482 nc->host_port = c->host_port;
1483 if (c->path != NULL)
1484 nc->path = xstrdup(c->path);
1485
1486 if (nextstate != SSH_CHANNEL_DYNAMIC)
1487 port_open_helper(nc, rtype);
1488 }
1489 }
1490
1491 /*
1492 * This is the authentication agent socket listening for connections from
1493 * clients.
1494 */
1495 /* ARGSUSED */
1496 static void
1497 channel_post_auth_listener(Channel *c, fd_set *readset, fd_set *writeset)
1498 {
1499 Channel *nc;
1500 int newsock;
1501 struct sockaddr_storage addr;
1502 socklen_t addrlen;
1503
1504 if (FD_ISSET(c->sock, readset)) {
1505 addrlen = sizeof(addr);
1506 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1507 if (newsock < 0) {
1508 error("accept from auth socket: %.100s", strerror(errno));
1509 return;
1510 }
1511 nc = channel_new("accepted auth socket",
1512 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1513 c->local_window_max, c->local_maxpacket,
1514 0, "accepted auth socket", 1);
1515 if (compat20) {
1516 packet_start(SSH2_MSG_CHANNEL_OPEN);
1517 packet_put_cstring("auth-agent@openssh.com");
1518 packet_put_int(nc->self);
1519 packet_put_int(c->local_window_max);
1520 packet_put_int(c->local_maxpacket);
1521 } else {
1522 packet_start(SSH_SMSG_AGENT_OPEN);
1523 packet_put_int(nc->self);
1524 }
1525 packet_send();
1526 }
1527 }
1528
1529 /* ARGSUSED */
1530 static void
1531 channel_post_connecting(Channel *c, fd_set *readset, fd_set *writeset)
1532 {
1533 int err = 0, sock;
1534 socklen_t sz = sizeof(err);
1535
1536 if (FD_ISSET(c->sock, writeset)) {
1537 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) {
1538 err = errno;
1539 error("getsockopt SO_ERROR failed");
1540 }
1541 if (err == 0) {
1542 debug("channel %d: connected to %s port %d",
1543 c->self, c->connect_ctx.host, c->connect_ctx.port);
1544 channel_connect_ctx_free(&c->connect_ctx);
1545 c->type = SSH_CHANNEL_OPEN;
1546 if (compat20) {
1547 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1548 packet_put_int(c->remote_id);
1549 packet_put_int(c->self);
1550 packet_put_int(c->local_window);
1551 packet_put_int(c->local_maxpacket);
1552 } else {
1553 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1554 packet_put_int(c->remote_id);
1555 packet_put_int(c->self);
1556 }
1557 } else {
1558 debug("channel %d: connection failed: %s",
1559 c->self, strerror(err));
1560 /* Try next address, if any */
1561 if ((sock = connect_next(&c->connect_ctx)) > 0) {
1562 close(c->sock);
1563 c->sock = c->rfd = c->wfd = sock;
1564 channel_max_fd = channel_find_maxfd();
1565 return;
1566 }
1567 /* Exhausted all addresses */
1568 error("connect_to %.100s port %d: failed.",
1569 c->connect_ctx.host, c->connect_ctx.port);
1570 channel_connect_ctx_free(&c->connect_ctx);
1571 if (compat20) {
1572 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1573 packet_put_int(c->remote_id);
1574 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1575 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1576 packet_put_cstring(strerror(err));
1577 packet_put_cstring("");
1578 }
1579 } else {
1580 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1581 packet_put_int(c->remote_id);
1582 }
1583 chan_mark_dead(c);
1584 }
1585 packet_send();
1586 }
1587 }
1588
1589 /* ARGSUSED */
1590 static int
1591 channel_handle_rfd(Channel *c, fd_set *readset, fd_set *writeset)
1592 {
1593 char buf[CHAN_RBUF];
1594 int len, force;
1595
1596 force = c->isatty && c->detach_close && c->istate != CHAN_INPUT_CLOSED;
1597 if (c->rfd != -1 && (force || FD_ISSET(c->rfd, readset))) {
1598 errno = 0;
1599 len = read(c->rfd, buf, sizeof(buf));
1600 if (len < 0 && (errno == EINTR ||
1601 ((errno == EAGAIN || errno == EWOULDBLOCK) && !force)))
1602 return 1;
1603 #ifndef PTY_ZEROREAD
1604 if (len <= 0) {
1605 #else
1606 if ((!c->isatty && len <= 0) ||
1607 (c->isatty && (len < 0 || (len == 0 && errno != 0)))) {
1608 #endif
1609 debug2("channel %d: read<=0 rfd %d len %d",
1610 c->self, c->rfd, len);
1611 if (c->type != SSH_CHANNEL_OPEN) {
1612 debug2("channel %d: not open", c->self);
1613 chan_mark_dead(c);
1614 return -1;
1615 } else if (compat13) {
1616 buffer_clear(&c->output);
1617 c->type = SSH_CHANNEL_INPUT_DRAINING;
1618 debug2("channel %d: input draining.", c->self);
1619 } else {
1620 chan_read_failed(c);
1621 }
1622 return -1;
1623 }
1624 if (c->input_filter != NULL) {
1625 if (c->input_filter(c, buf, len) == -1) {
1626 debug2("channel %d: filter stops", c->self);
1627 chan_read_failed(c);
1628 }
1629 } else if (c->datagram) {
1630 buffer_put_string(&c->input, buf, len);
1631 } else {
1632 buffer_append(&c->input, buf, len);
1633 }
1634 }
1635 return 1;
1636 }
1637
1638 /* ARGSUSED */
1639 static int
1640 channel_handle_wfd(Channel *c, fd_set *readset, fd_set *writeset)
1641 {
1642 struct termios tio;
1643 u_char *data = NULL, *buf;
1644 u_int dlen, olen = 0;
1645 int len;
1646
1647 /* Send buffered output data to the socket. */
1648 if (c->wfd != -1 &&
1649 FD_ISSET(c->wfd, writeset) &&
1650 buffer_len(&c->output) > 0) {
1651 olen = buffer_len(&c->output);
1652 if (c->output_filter != NULL) {
1653 if ((buf = c->output_filter(c, &data, &dlen)) == NULL) {
1654 debug2("channel %d: filter stops", c->self);
1655 if (c->type != SSH_CHANNEL_OPEN)
1656 chan_mark_dead(c);
1657 else
1658 chan_write_failed(c);
1659 return -1;
1660 }
1661 } else if (c->datagram) {
1662 buf = data = buffer_get_string(&c->output, &dlen);
1663 } else {
1664 buf = data = buffer_ptr(&c->output);
1665 dlen = buffer_len(&c->output);
1666 }
1667
1668 if (c->datagram) {
1669 /* ignore truncated writes, datagrams might get lost */
1670 len = write(c->wfd, buf, dlen);
1671 xfree(data);
1672 if (len < 0 && (errno == EINTR || errno == EAGAIN ||
1673 errno == EWOULDBLOCK))
1674 return 1;
1675 if (len <= 0) {
1676 if (c->type != SSH_CHANNEL_OPEN)
1677 chan_mark_dead(c);
1678 else
1679 chan_write_failed(c);
1680 return -1;
1681 }
1682 goto out;
1683 }
1684 #ifdef _AIX
1685 /* XXX: Later AIX versions can't push as much data to tty */
1686 if (compat20 && c->wfd_isatty)
1687 dlen = MIN(dlen, 8*1024);
1688 #endif
1689
1690 len = write(c->wfd, buf, dlen);
1691 if (len < 0 &&
1692 (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK))
1693 return 1;
1694 if (len <= 0) {
1695 if (c->type != SSH_CHANNEL_OPEN) {
1696 debug2("channel %d: not open", c->self);
1697 chan_mark_dead(c);
1698 return -1;
1699 } else if (compat13) {
1700 buffer_clear(&c->output);
1701 debug2("channel %d: input draining.", c->self);
1702 c->type = SSH_CHANNEL_INPUT_DRAINING;
1703 } else {
1704 chan_write_failed(c);
1705 }
1706 return -1;
1707 }
1708 #ifndef BROKEN_TCGETATTR_ICANON
1709 if (compat20 && c->isatty && dlen >= 1 && buf[0] != '\r') {
1710 if (tcgetattr(c->wfd, &tio) == 0 &&
1711 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1712 /*
1713 * Simulate echo to reduce the impact of
1714 * traffic analysis. We need to match the
1715 * size of a SSH2_MSG_CHANNEL_DATA message
1716 * (4 byte channel id + buf)
1717 */
1718 packet_send_ignore(4 + len);
1719 packet_send();
1720 }
1721 }
1722 #endif
1723 buffer_consume(&c->output, len);
1724 }
1725 out:
1726 if (compat20 && olen > 0)
1727 c->local_consumed += olen - buffer_len(&c->output);
1728 return 1;
1729 }
1730
1731 static int
1732 channel_handle_efd(Channel *c, fd_set *readset, fd_set *writeset)
1733 {
1734 char buf[CHAN_RBUF];
1735 int len;
1736
1737 /** XXX handle drain efd, too */
1738 if (c->efd != -1) {
1739 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1740 FD_ISSET(c->efd, writeset) &&
1741 buffer_len(&c->extended) > 0) {
1742 len = write(c->efd, buffer_ptr(&c->extended),
1743 buffer_len(&c->extended));
1744 debug2("channel %d: written %d to efd %d",
1745 c->self, len, c->efd);
1746 if (len < 0 && (errno == EINTR || errno == EAGAIN ||
1747 errno == EWOULDBLOCK))
1748 return 1;
1749 if (len <= 0) {
1750 debug2("channel %d: closing write-efd %d",
1751 c->self, c->efd);
1752 channel_close_fd(&c->efd);
1753 } else {
1754 buffer_consume(&c->extended, len);
1755 c->local_consumed += len;
1756 }
1757 } else if (c->efd != -1 &&
1758 (c->extended_usage == CHAN_EXTENDED_READ ||
1759 c->extended_usage == CHAN_EXTENDED_IGNORE) &&
1760 (c->detach_close || FD_ISSET(c->efd, readset))) {
1761 len = read(c->efd, buf, sizeof(buf));
1762 debug2("channel %d: read %d from efd %d",
1763 c->self, len, c->efd);
1764 if (len < 0 && (errno == EINTR || ((errno == EAGAIN ||
1765 errno == EWOULDBLOCK) && !c->detach_close)))
1766 return 1;
1767 if (len <= 0) {
1768 debug2("channel %d: closing read-efd %d",
1769 c->self, c->efd);
1770 channel_close_fd(&c->efd);
1771 } else {
1772 if (c->extended_usage == CHAN_EXTENDED_IGNORE) {
1773 debug3("channel %d: discard efd",
1774 c->self);
1775 } else
1776 buffer_append(&c->extended, buf, len);
1777 }
1778 }
1779 }
1780 return 1;
1781 }
1782
1783 static int
1784 channel_check_window(Channel *c)
1785 {
1786 if (c->type == SSH_CHANNEL_OPEN &&
1787 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1788 ((c->local_window_max - c->local_window >
1789 c->local_maxpacket*3) ||
1790 c->local_window < c->local_window_max/2) &&
1791 c->local_consumed > 0) {
1792 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1793 packet_put_int(c->remote_id);
1794 packet_put_int(c->local_consumed);
1795 packet_send();
1796 debug2("channel %d: window %d sent adjust %d",
1797 c->self, c->local_window,
1798 c->local_consumed);
1799 c->local_window += c->local_consumed;
1800 c->local_consumed = 0;
1801 }
1802 return 1;
1803 }
1804
1805 static void
1806 channel_post_open(Channel *c, fd_set *readset, fd_set *writeset)
1807 {
1808 channel_handle_rfd(c, readset, writeset);
1809 channel_handle_wfd(c, readset, writeset);
1810 if (!compat20)
1811 return;
1812 channel_handle_efd(c, readset, writeset);
1813 channel_check_window(c);
1814 }
1815
1816 static u_int
1817 read_mux(Channel *c, u_int need)
1818 {
1819 char buf[CHAN_RBUF];
1820 int len;
1821 u_int rlen;
1822
1823 if (buffer_len(&c->input) < need) {
1824 rlen = need - buffer_len(&c->input);
1825 len = read(c->rfd, buf, MIN(rlen, CHAN_RBUF));
1826 if (len <= 0) {
1827 if (errno != EINTR && errno != EAGAIN) {
1828 debug2("channel %d: ctl read<=0 rfd %d len %d",
1829 c->self, c->rfd, len);
1830 chan_read_failed(c);
1831 return 0;
1832 }
1833 } else
1834 buffer_append(&c->input, buf, len);
1835 }
1836 return buffer_len(&c->input);
1837 }
1838
1839 static void
1840 channel_post_mux_client(Channel *c, fd_set *readset, fd_set *writeset)
1841 {
1842 u_int need;
1843 ssize_t len;
1844
1845 if (!compat20)
1846 fatal("%s: entered with !compat20", __func__);
1847
1848 if (c->rfd != -1 && !c->mux_pause && FD_ISSET(c->rfd, readset) &&
1849 (c->istate == CHAN_INPUT_OPEN ||
1850 c->istate == CHAN_INPUT_WAIT_DRAIN)) {
1851 /*
1852 * Don't not read past the precise end of packets to
1853 * avoid disrupting fd passing.
1854 */
1855 if (read_mux(c, 4) < 4) /* read header */
1856 return;
1857 need = get_u32(buffer_ptr(&c->input));
1858 #define CHANNEL_MUX_MAX_PACKET (256 * 1024)
1859 if (need > CHANNEL_MUX_MAX_PACKET) {
1860 debug2("channel %d: packet too big %u > %u",
1861 c->self, CHANNEL_MUX_MAX_PACKET, need);
1862 chan_rcvd_oclose(c);
1863 return;
1864 }
1865 if (read_mux(c, need + 4) < need + 4) /* read body */
1866 return;
1867 if (c->mux_rcb(c) != 0) {
1868 debug("channel %d: mux_rcb failed", c->self);
1869 chan_mark_dead(c);
1870 return;
1871 }
1872 }
1873
1874 if (c->wfd != -1 && FD_ISSET(c->wfd, writeset) &&
1875 buffer_len(&c->output) > 0) {
1876 len = write(c->wfd, buffer_ptr(&c->output),
1877 buffer_len(&c->output));
1878 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1879 return;
1880 if (len <= 0) {
1881 chan_mark_dead(c);
1882 return;
1883 }
1884 buffer_consume(&c->output, len);
1885 }
1886 }
1887
1888 static void
1889 channel_post_mux_listener(Channel *c, fd_set *readset, fd_set *writeset)
1890 {
1891 Channel *nc;
1892 struct sockaddr_storage addr;
1893 socklen_t addrlen;
1894 int newsock;
1895 uid_t euid;
1896 gid_t egid;
1897
1898 if (!FD_ISSET(c->sock, readset))
1899 return;
1900
1901 debug("multiplexing control connection");
1902
1903 /*
1904 * Accept connection on control socket
1905 */
1906 memset(&addr, 0, sizeof(addr));
1907 addrlen = sizeof(addr);
1908 if ((newsock = accept(c->sock, (struct sockaddr*)&addr,
1909 &addrlen)) == -1) {
1910 error("%s accept: %s", __func__, strerror(errno));
1911 return;
1912 }
1913
1914 if (getpeereid(newsock, &euid, &egid) < 0) {
1915 error("%s getpeereid failed: %s", __func__,
1916 strerror(errno));
1917 close(newsock);
1918 return;
1919 }
1920 if ((euid != 0) && (getuid() != euid)) {
1921 error("multiplex uid mismatch: peer euid %u != uid %u",
1922 (u_int)euid, (u_int)getuid());
1923 close(newsock);
1924 return;
1925 }
1926 nc = channel_new("multiplex client", SSH_CHANNEL_MUX_CLIENT,
1927 newsock, newsock, -1, c->local_window_max,
1928 c->local_maxpacket, 0, "mux-control", 1);
1929 nc->mux_rcb = c->mux_rcb;
1930 debug3("%s: new mux channel %d fd %d", __func__,
1931 nc->self, nc->sock);
1932 /* establish state */
1933 nc->mux_rcb(nc);
1934 /* mux state transitions must not elicit protocol messages */
1935 nc->flags |= CHAN_LOCAL;
1936 }
1937
1938 /* ARGSUSED */
1939 static void
1940 channel_post_output_drain_13(Channel *c, fd_set *readset, fd_set *writeset)
1941 {
1942 int len;
1943
1944 /* Send buffered output data to the socket. */
1945 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1946 len = write(c->sock, buffer_ptr(&c->output),
1947 buffer_len(&c->output));
1948 if (len <= 0)
1949 buffer_clear(&c->output);
1950 else
1951 buffer_consume(&c->output, len);
1952 }
1953 }
1954
1955 static void
1956 channel_handler_init_20(void)
1957 {
1958 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1959 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1960 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1961 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
1962 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1963 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1964 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1965 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1966 channel_pre[SSH_CHANNEL_MUX_LISTENER] = &channel_pre_listener;
1967 channel_pre[SSH_CHANNEL_MUX_CLIENT] = &channel_pre_mux_client;
1968
1969 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1970 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1971 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
1972 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1973 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1974 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1975 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1976 channel_post[SSH_CHANNEL_MUX_LISTENER] = &channel_post_mux_listener;
1977 channel_post[SSH_CHANNEL_MUX_CLIENT] = &channel_post_mux_client;
1978 }
1979
1980 static void
1981 channel_handler_init_13(void)
1982 {
1983 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
1984 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
1985 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1986 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1987 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1988 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
1989 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1990 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1991 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1992
1993 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1994 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1995 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1996 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1997 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
1998 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1999 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
2000 }
2001
2002 static void
2003 channel_handler_init_15(void)
2004 {
2005 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
2006 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
2007 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
2008 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
2009 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
2010 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
2011 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
2012
2013 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
2014 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
2015 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
2016 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
2017 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
2018 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
2019 }
2020
2021 static void
2022 channel_handler_init(void)
2023 {
2024 int i;
2025
2026 for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
2027 channel_pre[i] = NULL;
2028 channel_post[i] = NULL;
2029 }
2030 if (compat20)
2031 channel_handler_init_20();
2032 else if (compat13)
2033 channel_handler_init_13();
2034 else
2035 channel_handler_init_15();
2036 }
2037
2038 /* gc dead channels */
2039 static void
2040 channel_garbage_collect(Channel *c)
2041 {
2042 if (c == NULL)
2043 return;
2044 if (c->detach_user != NULL) {
2045 if (!chan_is_dead(c, c->detach_close))
2046 return;
2047 debug2("channel %d: gc: notify user", c->self);
2048 c->detach_user(c->self, NULL);
2049 /* if we still have a callback */
2050 if (c->detach_user != NULL)
2051 return;
2052 debug2("channel %d: gc: user detached", c->self);
2053 }
2054 if (!chan_is_dead(c, 1))
2055 return;
2056 debug2("channel %d: garbage collecting", c->self);
2057 channel_free(c);
2058 }
2059
2060 static void
2061 channel_handler(chan_fn *ftab[], fd_set *readset, fd_set *writeset)
2062 {
2063 static int did_init = 0;
2064 u_int i, oalloc;
2065 Channel *c;
2066
2067 if (!did_init) {
2068 channel_handler_init();
2069 did_init = 1;
2070 }
2071 for (i = 0, oalloc = channels_alloc; i < oalloc; i++) {
2072 c = channels[i];
2073 if (c == NULL)
2074 continue;
2075 if (c->delayed) {
2076 if (ftab == channel_pre)
2077 c->delayed = 0;
2078 else
2079 continue;
2080 }
2081 if (ftab[c->type] != NULL)
2082 (*ftab[c->type])(c, readset, writeset);
2083 channel_garbage_collect(c);
2084 }
2085 }
2086
2087 /*
2088 * Allocate/update select bitmasks and add any bits relevant to channels in
2089 * select bitmasks.
2090 */
2091 void
2092 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
2093 u_int *nallocp, int rekeying)
2094 {
2095 u_int n, sz, nfdset;
2096
2097 n = MAX(*maxfdp, channel_max_fd);
2098
2099 nfdset = howmany(n+1, NFDBITS);
2100 /* Explicitly test here, because xrealloc isn't always called */
2101 if (nfdset && SIZE_T_MAX / nfdset < sizeof(fd_mask))
2102 fatal("channel_prepare_select: max_fd (%d) is too large", n);
2103 sz = nfdset * sizeof(fd_mask);
2104
2105 /* perhaps check sz < nalloc/2 and shrink? */
2106 if (*readsetp == NULL || sz > *nallocp) {
2107 *readsetp = xrealloc(*readsetp, nfdset, sizeof(fd_mask));
2108 *writesetp = xrealloc(*writesetp, nfdset, sizeof(fd_mask));
2109 *nallocp = sz;
2110 }
2111 *maxfdp = n;
2112 memset(*readsetp, 0, sz);
2113 memset(*writesetp, 0, sz);
2114
2115 if (!rekeying)
2116 channel_handler(channel_pre, *readsetp, *writesetp);
2117 }
2118
2119 /*
2120 * After select, perform any appropriate operations for channels which have
2121 * events pending.
2122 */
2123 void
2124 channel_after_select(fd_set *readset, fd_set *writeset)
2125 {
2126 channel_handler(channel_post, readset, writeset);
2127 }
2128
2129
2130 /* If there is data to send to the connection, enqueue some of it now. */
2131 void
2132 channel_output_poll(void)
2133 {
2134 Channel *c;
2135 u_int i, len;
2136
2137 for (i = 0; i < channels_alloc; i++) {
2138 c = channels[i];
2139 if (c == NULL)
2140 continue;
2141
2142 /*
2143 * We are only interested in channels that can have buffered
2144 * incoming data.
2145 */
2146 if (compat13) {
2147 if (c->type != SSH_CHANNEL_OPEN &&
2148 c->type != SSH_CHANNEL_INPUT_DRAINING)
2149 continue;
2150 } else {
2151 if (c->type != SSH_CHANNEL_OPEN)
2152 continue;
2153 }
2154 if (compat20 &&
2155 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
2156 /* XXX is this true? */
2157 debug3("channel %d: will not send data after close", c->self);
2158 continue;
2159 }
2160
2161 /* Get the amount of buffered data for this channel. */
2162 if ((c->istate == CHAN_INPUT_OPEN ||
2163 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
2164 (len = buffer_len(&c->input)) > 0) {
2165 if (c->datagram) {
2166 if (len > 0) {
2167 u_char *data;
2168 u_int dlen;
2169
2170 data = buffer_get_string(&c->input,
2171 &dlen);
2172 if (dlen > c->remote_window ||
2173 dlen > c->remote_maxpacket) {
2174 debug("channel %d: datagram "
2175 "too big for channel",
2176 c->self);
2177 xfree(data);
2178 continue;
2179 }
2180 packet_start(SSH2_MSG_CHANNEL_DATA);
2181 packet_put_int(c->remote_id);
2182 packet_put_string(data, dlen);
2183 packet_send();
2184 c->remote_window -= dlen + 4;
2185 xfree(data);
2186 }
2187 continue;
2188 }
2189 /*
2190 * Send some data for the other side over the secure
2191 * connection.
2192 */
2193 if (compat20) {
2194 if (len > c->remote_window)
2195 len = c->remote_window;
2196 if (len > c->remote_maxpacket)
2197 len = c->remote_maxpacket;
2198 } else {
2199 if (packet_is_interactive()) {
2200 if (len > 1024)
2201 len = 512;
2202 } else {
2203 /* Keep the packets at reasonable size. */
2204 if (len > packet_get_maxsize()/2)
2205 len = packet_get_maxsize()/2;
2206 }
2207 }
2208 if (len > 0) {
2209 packet_start(compat20 ?
2210 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
2211 packet_put_int(c->remote_id);
2212 packet_put_string(buffer_ptr(&c->input), len);
2213 packet_send();
2214 buffer_consume(&c->input, len);
2215 c->remote_window -= len;
2216 }
2217 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
2218 if (compat13)
2219 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
2220 /*
2221 * input-buffer is empty and read-socket shutdown:
2222 * tell peer, that we will not send more data: send IEOF.
2223 * hack for extended data: delay EOF if EFD still in use.
2224 */
2225 if (CHANNEL_EFD_INPUT_ACTIVE(c))
2226 debug2("channel %d: ibuf_empty delayed efd %d/(%d)",
2227 c->self, c->efd, buffer_len(&c->extended));
2228 else
2229 chan_ibuf_empty(c);
2230 }
2231 /* Send extended data, i.e. stderr */
2232 if (compat20 &&
2233 !(c->flags & CHAN_EOF_SENT) &&
2234 c->remote_window > 0 &&
2235 (len = buffer_len(&c->extended)) > 0 &&
2236 c->extended_usage == CHAN_EXTENDED_READ) {
2237 debug2("channel %d: rwin %u elen %u euse %d",
2238 c->self, c->remote_window, buffer_len(&c->extended),
2239 c->extended_usage);
2240 if (len > c->remote_window)
2241 len = c->remote_window;
2242 if (len > c->remote_maxpacket)
2243 len = c->remote_maxpacket;
2244 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
2245 packet_put_int(c->remote_id);
2246 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
2247 packet_put_string(buffer_ptr(&c->extended), len);
2248 packet_send();
2249 buffer_consume(&c->extended, len);
2250 c->remote_window -= len;
2251 debug2("channel %d: sent ext data %d", c->self, len);
2252 }
2253 }
2254 }
2255
2256
2257 /* -- protocol input */
2258
2259 /* ARGSUSED */
2260 void
2261 channel_input_data(int type, u_int32_t seq, void *ctxt)
2262 {
2263 int id;
2264 char *data;
2265 u_int data_len, win_len;
2266 Channel *c;
2267
2268 /* Get the channel number and verify it. */
2269 id = packet_get_int();
2270 c = channel_lookup(id);
2271 if (c == NULL)
2272 packet_disconnect("Received data for nonexistent channel %d.", id);
2273
2274 /* Ignore any data for non-open channels (might happen on close) */
2275 if (c->type != SSH_CHANNEL_OPEN &&
2276 c->type != SSH_CHANNEL_X11_OPEN)
2277 return;
2278
2279 /* Get the data. */
2280 data = packet_get_string_ptr(&data_len);
2281 win_len = data_len;
2282 if (c->datagram)
2283 win_len += 4; /* string length header */
2284
2285 /*
2286 * Ignore data for protocol > 1.3 if output end is no longer open.
2287 * For protocol 2 the sending side is reducing its window as it sends
2288 * data, so we must 'fake' consumption of the data in order to ensure
2289 * that window updates are sent back. Otherwise the connection might
2290 * deadlock.
2291 */
2292 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) {
2293 if (compat20) {
2294 c->local_window -= win_len;
2295 c->local_consumed += win_len;
2296 }
2297 return;
2298 }
2299
2300 if (compat20) {
2301 if (win_len > c->local_maxpacket) {
2302 logit("channel %d: rcvd big packet %d, maxpack %d",
2303 c->self, win_len, c->local_maxpacket);
2304 }
2305 if (win_len > c->local_window) {
2306 logit("channel %d: rcvd too much data %d, win %d",
2307 c->self, win_len, c->local_window);
2308 return;
2309 }
2310 c->local_window -= win_len;
2311 }
2312 if (c->datagram)
2313 buffer_put_string(&c->output, data, data_len);
2314 else
2315 buffer_append(&c->output, data, data_len);
2316 packet_check_eom();
2317 }
2318
2319 /* ARGSUSED */
2320 void
2321 channel_input_extended_data(int type, u_int32_t seq, void *ctxt)
2322 {
2323 int id;
2324 char *data;
2325 u_int data_len, tcode;
2326 Channel *c;
2327
2328 /* Get the channel number and verify it. */
2329 id = packet_get_int();
2330 c = channel_lookup(id);
2331
2332 if (c == NULL)
2333 packet_disconnect("Received extended_data for bad channel %d.", id);
2334 if (c->type != SSH_CHANNEL_OPEN) {
2335 logit("channel %d: ext data for non open", id);
2336 return;
2337 }
2338 if (c->flags & CHAN_EOF_RCVD) {
2339 if (datafellows & SSH_BUG_EXTEOF)
2340 debug("channel %d: accepting ext data after eof", id);
2341 else
2342 packet_disconnect("Received extended_data after EOF "
2343 "on channel %d.", id);
2344 }
2345 tcode = packet_get_int();
2346 if (c->efd == -1 ||
2347 c->extended_usage != CHAN_EXTENDED_WRITE ||
2348 tcode != SSH2_EXTENDED_DATA_STDERR) {
2349 logit("channel %d: bad ext data", c->self);
2350 return;
2351 }
2352 data = packet_get_string(&data_len);
2353 packet_check_eom();
2354 if (data_len > c->local_window) {
2355 logit("channel %d: rcvd too much extended_data %d, win %d",
2356 c->self, data_len, c->local_window);
2357 xfree(data);
2358 return;
2359 }
2360 debug2("channel %d: rcvd ext data %d", c->self, data_len);
2361 c->local_window -= data_len;
2362 buffer_append(&c->extended, data, data_len);
2363 xfree(data);
2364 }
2365
2366 /* ARGSUSED */
2367 void
2368 channel_input_ieof(int type, u_int32_t seq, void *ctxt)
2369 {
2370 int id;
2371 Channel *c;
2372
2373 id = packet_get_int();
2374 packet_check_eom();
2375 c = channel_lookup(id);
2376 if (c == NULL)
2377 packet_disconnect("Received ieof for nonexistent channel %d.", id);
2378 chan_rcvd_ieof(c);
2379
2380 /* XXX force input close */
2381 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) {
2382 debug("channel %d: FORCE input drain", c->self);
2383 c->istate = CHAN_INPUT_WAIT_DRAIN;
2384 if (buffer_len(&c->input) == 0)
2385 chan_ibuf_empty(c);
2386 }
2387
2388 }
2389
2390 /* ARGSUSED */
2391 void
2392 channel_input_close(int type, u_int32_t seq, void *ctxt)
2393 {
2394 int id;
2395 Channel *c;
2396
2397 id = packet_get_int();
2398 packet_check_eom();
2399 c = channel_lookup(id);
2400 if (c == NULL)
2401 packet_disconnect("Received close for nonexistent channel %d.", id);
2402
2403 /*
2404 * Send a confirmation that we have closed the channel and no more
2405 * data is coming for it.
2406 */
2407 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
2408 packet_put_int(c->remote_id);
2409 packet_send();
2410
2411 /*
2412 * If the channel is in closed state, we have sent a close request,
2413 * and the other side will eventually respond with a confirmation.
2414 * Thus, we cannot free the channel here, because then there would be
2415 * no-one to receive the confirmation. The channel gets freed when
2416 * the confirmation arrives.
2417 */
2418 if (c->type != SSH_CHANNEL_CLOSED) {
2419 /*
2420 * Not a closed channel - mark it as draining, which will
2421 * cause it to be freed later.
2422 */
2423 buffer_clear(&c->input);
2424 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
2425 }
2426 }
2427
2428 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
2429 /* ARGSUSED */
2430 void
2431 channel_input_oclose(int type, u_int32_t seq, void *ctxt)
2432 {
2433 int id = packet_get_int();
2434 Channel *c = channel_lookup(id);
2435
2436 packet_check_eom();
2437 if (c == NULL)
2438 packet_disconnect("Received oclose for nonexistent channel %d.", id);
2439 chan_rcvd_oclose(c);
2440 }
2441
2442 /* ARGSUSED */
2443 void
2444 channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt)
2445 {
2446 int id = packet_get_int();
2447 Channel *c = channel_lookup(id);
2448
2449 packet_check_eom();
2450 if (c == NULL)
2451 packet_disconnect("Received close confirmation for "
2452 "out-of-range channel %d.", id);
2453 if (c->type != SSH_CHANNEL_CLOSED)
2454 packet_disconnect("Received close confirmation for "
2455 "non-closed channel %d (type %d).", id, c->type);
2456 channel_free(c);
2457 }
2458
2459 /* ARGSUSED */
2460 void
2461 channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt)
2462 {
2463 int id, remote_id;
2464 Channel *c;
2465
2466 id = packet_get_int();
2467 c = channel_lookup(id);
2468
2469 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2470 packet_disconnect("Received open confirmation for "
2471 "non-opening channel %d.", id);
2472 remote_id = packet_get_int();
2473 /* Record the remote channel number and mark that the channel is now open. */
2474 c->remote_id = remote_id;
2475 c->type = SSH_CHANNEL_OPEN;
2476
2477 if (compat20) {
2478 c->remote_window = packet_get_int();
2479 c->remote_maxpacket = packet_get_int();
2480 if (c->open_confirm) {
2481 debug2("callback start");
2482 c->open_confirm(c->self, 1, c->open_confirm_ctx);
2483 debug2("callback done");
2484 }
2485 debug2("channel %d: open confirm rwindow %u rmax %u", c->self,
2486 c->remote_window, c->remote_maxpacket);
2487 }
2488 packet_check_eom();
2489 }
2490
2491 static char *
2492 reason2txt(int reason)
2493 {
2494 switch (reason) {
2495 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
2496 return "administratively prohibited";
2497 case SSH2_OPEN_CONNECT_FAILED:
2498 return "connect failed";
2499 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
2500 return "unknown channel type";
2501 case SSH2_OPEN_RESOURCE_SHORTAGE:
2502 return "resource shortage";
2503 }
2504 return "unknown reason";
2505 }
2506
2507 /* ARGSUSED */
2508 void
2509 channel_input_open_failure(int type, u_int32_t seq, void *ctxt)
2510 {
2511 int id, reason;
2512 char *msg = NULL, *lang = NULL;
2513 Channel *c;
2514
2515 id = packet_get_int();
2516 c = channel_lookup(id);
2517
2518 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2519 packet_disconnect("Received open failure for "
2520 "non-opening channel %d.", id);
2521 if (compat20) {
2522 reason = packet_get_int();
2523 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
2524 msg = packet_get_string(NULL);
2525 lang = packet_get_string(NULL);
2526 }
2527 logit("channel %d: open failed: %s%s%s", id,
2528 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
2529 if (msg != NULL)
2530 xfree(msg);
2531 if (lang != NULL)
2532 xfree(lang);
2533 if (c->open_confirm) {
2534 debug2("callback start");
2535 c->open_confirm(c->self, 0, c->open_confirm_ctx);
2536 debug2("callback done");
2537 }
2538 }
2539 packet_check_eom();
2540 /* Schedule the channel for cleanup/deletion. */
2541 chan_mark_dead(c);
2542 }
2543
2544 /* ARGSUSED */
2545 void
2546 channel_input_window_adjust(int type, u_int32_t seq, void *ctxt)
2547 {
2548 Channel *c;
2549 int id;
2550 u_int adjust;
2551
2552 if (!compat20)
2553 return;
2554
2555 /* Get the channel number and verify it. */
2556 id = packet_get_int();
2557 c = channel_lookup(id);
2558
2559 if (c == NULL) {
2560 logit("Received window adjust for non-open channel %d.", id);
2561 return;
2562 }
2563 adjust = packet_get_int();
2564 packet_check_eom();
2565 debug2("channel %d: rcvd adjust %u", id, adjust);
2566 c->remote_window += adjust;
2567 }
2568
2569 /* ARGSUSED */
2570 void
2571 channel_input_port_open(int type, u_int32_t seq, void *ctxt)
2572 {
2573 Channel *c = NULL;
2574 u_short host_port;
2575 char *host, *originator_string;
2576 int remote_id;
2577
2578 remote_id = packet_get_int();
2579 host = packet_get_string(NULL);
2580 host_port = packet_get_int();
2581
2582 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2583 originator_string = packet_get_string(NULL);
2584 } else {
2585 originator_string = xstrdup("unknown (remote did not supply name)");
2586 }
2587 packet_check_eom();
2588 c = channel_connect_to(host, host_port,
2589 "connected socket", originator_string);
2590 xfree(originator_string);
2591 xfree(host);
2592 if (c == NULL) {
2593 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2594 packet_put_int(remote_id);
2595 packet_send();
2596 } else
2597 c->remote_id = remote_id;
2598 }
2599
2600 /* ARGSUSED */
2601 void
2602 channel_input_status_confirm(int type, u_int32_t seq, void *ctxt)
2603 {
2604 Channel *c;
2605 struct channel_confirm *cc;
2606 int id;
2607
2608 /* Reset keepalive timeout */
2609 packet_set_alive_timeouts(0);
2610
2611 id = packet_get_int();
2612 packet_check_eom();
2613
2614 debug2("channel_input_status_confirm: type %d id %d", type, id);
2615
2616 if ((c = channel_lookup(id)) == NULL) {
2617 logit("channel_input_status_confirm: %d: unknown", id);
2618 return;
2619 }
2620 ;
2621 if ((cc = TAILQ_FIRST(&c->status_confirms)) == NULL)
2622 return;
2623 cc->cb(type, c, cc->ctx);
2624 TAILQ_REMOVE(&c->status_confirms, cc, entry);
2625 bzero(cc, sizeof(*cc));
2626 xfree(cc);
2627 }
2628
2629 /* -- tcp forwarding */
2630
2631 void
2632 channel_set_af(int af)
2633 {
2634 IPv4or6 = af;
2635 }
2636
2637 static int
2638 channel_setup_fwd_listener(int type, const char *listen_addr,
2639 u_short listen_port, int *allocated_listen_port,
2640 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2641 {
2642 Channel *c;
2643 int sock, r, success = 0, wildcard = 0, is_client;
2644 struct addrinfo hints, *ai, *aitop;
2645 const char *host, *addr;
2646 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2647 in_port_t *lport_p;
2648
2649 host = (type == SSH_CHANNEL_RPORT_LISTENER) ?
2650 listen_addr : host_to_connect;
2651 is_client = (type == SSH_CHANNEL_PORT_LISTENER);
2652
2653 if (host == NULL) {
2654 error("No forward host name.");
2655 return 0;
2656 }
2657 if (strlen(host) >= NI_MAXHOST) {
2658 error("Forward host name too long.");
2659 return 0;
2660 }
2661
2662 /*
2663 * Determine whether or not a port forward listens to loopback,
2664 * specified address or wildcard. On the client, a specified bind
2665 * address will always override gateway_ports. On the server, a
2666 * gateway_ports of 1 (``yes'') will override the client's
2667 * specification and force a wildcard bind, whereas a value of 2
2668 * (``clientspecified'') will bind to whatever address the client
2669 * asked for.
2670 *
2671 * Special-case listen_addrs are:
2672 *
2673 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR
2674 * "" (empty string), "*" -> wildcard v4/v6
2675 * "localhost" -> loopback v4/v6
2676 */
2677 addr = NULL;
2678 if (listen_addr == NULL) {
2679 /* No address specified: default to gateway_ports setting */
2680 if (gateway_ports)
2681 wildcard = 1;
2682 } else if (gateway_ports || is_client) {
2683 if (((datafellows & SSH_OLD_FORWARD_ADDR) &&
2684 strcmp(listen_addr, "0.0.0.0") == 0 && is_client == 0) ||
2685 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 ||
2686 (!is_client && gateway_ports == 1))
2687 wildcard = 1;
2688 else if (strcmp(listen_addr, "localhost") != 0)
2689 addr = listen_addr;
2690 }
2691
2692 debug3("channel_setup_fwd_listener: type %d wildcard %d addr %s",
2693 type, wildcard, (addr == NULL) ? "NULL" : addr);
2694
2695 /*
2696 * getaddrinfo returns a loopback address if the hostname is
2697 * set to NULL and hints.ai_flags is not AI_PASSIVE
2698 */
2699 memset(&hints, 0, sizeof(hints));
2700 hints.ai_family = IPv4or6;
2701 hints.ai_flags = wildcard ? AI_PASSIVE : 0;
2702 hints.ai_socktype = SOCK_STREAM;
2703 snprintf(strport, sizeof strport, "%d", listen_port);
2704 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) {
2705 if (addr == NULL) {
2706 /* This really shouldn't happen */
2707 packet_disconnect("getaddrinfo: fatal error: %s",
2708 ssh_gai_strerror(r));
2709 } else {
2710 error("channel_setup_fwd_listener: "
2711 "getaddrinfo(%.64s): %s", addr,
2712 ssh_gai_strerror(r));
2713 }
2714 return 0;
2715 }
2716 if (allocated_listen_port != NULL)
2717 *allocated_listen_port = 0;
2718 for (ai = aitop; ai; ai = ai->ai_next) {
2719 switch (ai->ai_family) {
2720 case AF_INET:
2721 lport_p = &((struct sockaddr_in *)ai->ai_addr)->
2722 sin_port;
2723 break;
2724 case AF_INET6:
2725 lport_p = &((struct sockaddr_in6 *)ai->ai_addr)->
2726 sin6_port;
2727 break;
2728 default:
2729 continue;
2730 }
2731 /*
2732 * If allocating a port for -R forwards, then use the
2733 * same port for all address families.
2734 */
2735 if (type == SSH_CHANNEL_RPORT_LISTENER && listen_port == 0 &&
2736 allocated_listen_port != NULL && *allocated_listen_port > 0)
2737 *lport_p = htons(*allocated_listen_port);
2738
2739 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2740 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2741 error("channel_setup_fwd_listener: getnameinfo failed");
2742 continue;
2743 }
2744 /* Create a port to listen for the host. */
2745 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2746 if (sock < 0) {
2747 /* this is no error since kernel may not support ipv6 */
2748 verbose("socket: %.100s", strerror(errno));
2749 continue;
2750 }
2751
2752 channel_set_reuseaddr(sock);
2753 if (ai->ai_family == AF_INET6)
2754 sock_set_v6only(sock);
2755
2756 debug("Local forwarding listening on %s port %s.",
2757 ntop, strport);
2758
2759 /* Bind the socket to the address. */
2760 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2761 /* address can be in use ipv6 address is already bound */
2762 if (!ai->ai_next)
2763 error("bind: %.100s", strerror(errno));
2764 else
2765 verbose("bind: %.100s", strerror(errno));
2766
2767 close(sock);
2768 continue;
2769 }
2770 /* Start listening for connections on the socket. */
2771 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2772 error("listen: %.100s", strerror(errno));
2773 close(sock);
2774 continue;
2775 }
2776
2777 /*
2778 * listen_port == 0 requests a dynamically allocated port -
2779 * record what we got.
2780 */
2781 if (type == SSH_CHANNEL_RPORT_LISTENER && listen_port == 0 &&
2782 allocated_listen_port != NULL &&
2783 *allocated_listen_port == 0) {
2784 *allocated_listen_port = get_sock_port(sock, 1);
2785 debug("Allocated listen port %d",
2786 *allocated_listen_port);
2787 }
2788
2789 /* Allocate a channel number for the socket. */
2790 c = channel_new("port listener", type, sock, sock, -1,
2791 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2792 0, "port listener", 1);
2793 c->path = xstrdup(host);
2794 c->host_port = port_to_connect;
2795 c->listening_port = listen_port;
2796 success = 1;
2797 }
2798 if (success == 0)
2799 error("channel_setup_fwd_listener: cannot listen to port: %d",
2800 listen_port);
2801 freeaddrinfo(aitop);
2802 return success;
2803 }
2804
2805 int
2806 channel_cancel_rport_listener(const char *host, u_short port)
2807 {
2808 u_int i;
2809 int found = 0;
2810
2811 for (i = 0; i < channels_alloc; i++) {
2812 Channel *c = channels[i];
2813
2814 if (c != NULL && c->type == SSH_CHANNEL_RPORT_LISTENER &&
2815 strcmp(c->path, host) == 0 && c->listening_port == port) {
2816 debug2("%s: close channel %d", __func__, i);
2817 channel_free(c);
2818 found = 1;
2819 }
2820 }
2821
2822 return (found);
2823 }
2824
2825 /* protocol local port fwd, used by ssh (and sshd in v1) */
2826 int
2827 channel_setup_local_fwd_listener(const char *listen_host, u_short listen_port,
2828 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2829 {
2830 return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER,
2831 listen_host, listen_port, NULL, host_to_connect, port_to_connect,
2832 gateway_ports);
2833 }
2834
2835 /* protocol v2 remote port fwd, used by sshd */
2836 int
2837 channel_setup_remote_fwd_listener(const char *listen_address,
2838 u_short listen_port, int *allocated_listen_port, int gateway_ports)
2839 {
2840 return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER,
2841 listen_address, listen_port, allocated_listen_port,
2842 NULL, 0, gateway_ports);
2843 }
2844
2845 /*
2846 * Initiate forwarding of connections to port "port" on remote host through
2847 * the secure channel to host:port from local side.
2848 */
2849
2850 int
2851 channel_request_remote_forwarding(const char *listen_host, u_short listen_port,
2852 const char *host_to_connect, u_short port_to_connect)
2853 {
2854 int type, success = 0;
2855
2856 /* Send the forward request to the remote side. */
2857 if (compat20) {
2858 const char *address_to_bind;
2859 if (listen_host == NULL) {
2860 if (datafellows & SSH_BUG_RFWD_ADDR)
2861 address_to_bind = "127.0.0.1";
2862 else
2863 address_to_bind = "localhost";
2864 } else if (*listen_host == '\0' ||
2865 strcmp(listen_host, "*") == 0) {
2866 if (datafellows & SSH_BUG_RFWD_ADDR)
2867 address_to_bind = "0.0.0.0";
2868 else
2869 address_to_bind = "";
2870 } else
2871 address_to_bind = listen_host;
2872
2873 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2874 packet_put_cstring("tcpip-forward");
2875 packet_put_char(1); /* boolean: want reply */
2876 packet_put_cstring(address_to_bind);
2877 packet_put_int(listen_port);
2878 packet_send();
2879 packet_write_wait();
2880 /* Assume that server accepts the request */
2881 success = 1;
2882 } else {
2883 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2884 packet_put_int(listen_port);
2885 packet_put_cstring(host_to_connect);
2886 packet_put_int(port_to_connect);
2887 packet_send();
2888 packet_write_wait();
2889
2890 /* Wait for response from the remote side. */
2891 type = packet_read();
2892 switch (type) {
2893 case SSH_SMSG_SUCCESS:
2894 success = 1;
2895 break;
2896 case SSH_SMSG_FAILURE:
2897 break;
2898 default:
2899 /* Unknown packet */
2900 packet_disconnect("Protocol error for port forward request:"
2901 "received packet type %d.", type);
2902 }
2903 }
2904 if (success) {
2905 /* Record that connection to this host/port is permitted. */
2906 permitted_opens = xrealloc(permitted_opens,
2907 num_permitted_opens + 1, sizeof(*permitted_opens));
2908 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2909 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2910 permitted_opens[num_permitted_opens].listen_port = listen_port;
2911 num_permitted_opens++;
2912 }
2913 return (success ? 0 : -1);
2914 }
2915
2916 /*
2917 * Request cancellation of remote forwarding of connection host:port from
2918 * local side.
2919 */
2920 void
2921 channel_request_rforward_cancel(const char *host, u_short port)
2922 {
2923 int i;
2924
2925 if (!compat20)
2926 return;
2927
2928 for (i = 0; i < num_permitted_opens; i++) {
2929 if (permitted_opens[i].host_to_connect != NULL &&
2930 permitted_opens[i].listen_port == port)
2931 break;
2932 }
2933 if (i >= num_permitted_opens) {
2934 debug("%s: requested forward not found", __func__);
2935 return;
2936 }
2937 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2938 packet_put_cstring("cancel-tcpip-forward");
2939 packet_put_char(0);
2940 packet_put_cstring(host == NULL ? "" : host);
2941 packet_put_int(port);
2942 packet_send();
2943
2944 permitted_opens[i].listen_port = 0;
2945 permitted_opens[i].port_to_connect = 0;
2946 xfree(permitted_opens[i].host_to_connect);
2947 permitted_opens[i].host_to_connect = NULL;
2948 }
2949
2950 /*
2951 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
2952 * listening for the port, and sends back a success reply (or disconnect
2953 * message if there was an error).
2954 */
2955 int
2956 channel_input_port_forward_request(int is_root, int gateway_ports)
2957 {
2958 u_short port, host_port;
2959 int success = 0;
2960 char *hostname;
2961
2962 /* Get arguments from the packet. */
2963 port = packet_get_int();
2964 hostname = packet_get_string(NULL);
2965 host_port = packet_get_int();
2966
2967 #ifndef HAVE_CYGWIN
2968 /*
2969 * Check that an unprivileged user is not trying to forward a
2970 * privileged port.
2971 */
2972 if (port < IPPORT_RESERVED && !is_root)
2973 packet_disconnect(
2974 "Requested forwarding of port %d but user is not root.",
2975 port);
2976 if (host_port == 0)
2977 packet_disconnect("Dynamic forwarding denied.");
2978 #endif
2979
2980 /* Initiate forwarding */
2981 success = channel_setup_local_fwd_listener(NULL, port, hostname,
2982 host_port, gateway_ports);
2983
2984 /* Free the argument string. */
2985 xfree(hostname);
2986
2987 return (success ? 0 : -1);
2988 }
2989
2990 /*
2991 * Permits opening to any host/port if permitted_opens[] is empty. This is
2992 * usually called by the server, because the user could connect to any port
2993 * anyway, and the server has no way to know but to trust the client anyway.
2994 */
2995 void
2996 channel_permit_all_opens(void)
2997 {
2998 if (num_permitted_opens == 0)
2999 all_opens_permitted = 1;
3000 }
3001
3002 void
3003 channel_add_permitted_opens(char *host, int port)
3004 {
3005 debug("allow port forwarding to host %s port %d", host, port);
3006
3007 permitted_opens = xrealloc(permitted_opens,
3008 num_permitted_opens + 1, sizeof(*permitted_opens));
3009 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
3010 permitted_opens[num_permitted_opens].port_to_connect = port;
3011 num_permitted_opens++;
3012
3013 all_opens_permitted = 0;
3014 }
3015
3016 int
3017 channel_add_adm_permitted_opens(char *host, int port)
3018 {
3019 debug("config allows port forwarding to host %s port %d", host, port);
3020
3021 permitted_adm_opens = xrealloc(permitted_adm_opens,
3022 num_adm_permitted_opens + 1, sizeof(*permitted_adm_opens));
3023 permitted_adm_opens[num_adm_permitted_opens].host_to_connect
3024 = xstrdup(host);
3025 permitted_adm_opens[num_adm_permitted_opens].port_to_connect = port;
3026 return ++num_adm_permitted_opens;
3027 }
3028
3029 void
3030 channel_clear_permitted_opens(void)
3031 {
3032 int i;
3033
3034 for (i = 0; i < num_permitted_opens; i++)
3035 if (permitted_opens[i].host_to_connect != NULL)
3036 xfree(permitted_opens[i].host_to_connect);
3037 if (num_permitted_opens > 0) {
3038 xfree(permitted_opens);
3039 permitted_opens = NULL;
3040 }
3041 num_permitted_opens = 0;
3042 }
3043
3044 void
3045 channel_clear_adm_permitted_opens(void)
3046 {
3047 int i;
3048
3049 for (i = 0; i < num_adm_permitted_opens; i++)
3050 if (permitted_adm_opens[i].host_to_connect != NULL)
3051 xfree(permitted_adm_opens[i].host_to_connect);
3052 if (num_adm_permitted_opens > 0) {
3053 xfree(permitted_adm_opens);
3054 permitted_adm_opens = NULL;
3055 }
3056 num_adm_permitted_opens = 0;
3057 }
3058
3059 void
3060 channel_print_adm_permitted_opens(void)
3061 {
3062 int i;
3063
3064 printf("permitopen");
3065 if (num_adm_permitted_opens == 0) {
3066 printf(" any\n");
3067 return;
3068 }
3069 for (i = 0; i < num_adm_permitted_opens; i++)
3070 if (permitted_adm_opens[i].host_to_connect != NULL)
3071 printf(" %s:%d", permitted_adm_opens[i].host_to_connect,
3072 permitted_adm_opens[i].port_to_connect);
3073 printf("\n");
3074 }
3075
3076 /* Try to start non-blocking connect to next host in cctx list */
3077 static int
3078 connect_next(struct channel_connect *cctx)
3079 {
3080 int sock, saved_errno;
3081 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
3082
3083 for (; cctx->ai; cctx->ai = cctx->ai->ai_next) {
3084 if (cctx->ai->ai_family != AF_INET &&
3085 cctx->ai->ai_family != AF_INET6)
3086 continue;
3087 if (getnameinfo(cctx->ai->ai_addr, cctx->ai->ai_addrlen,
3088 ntop, sizeof(ntop), strport, sizeof(strport),
3089 NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
3090 error("connect_next: getnameinfo failed");
3091 continue;
3092 }
3093 if ((sock = socket(cctx->ai->ai_family, cctx->ai->ai_socktype,
3094 cctx->ai->ai_protocol)) == -1) {
3095 if (cctx->ai->ai_next == NULL)
3096 error("socket: %.100s", strerror(errno));
3097 else
3098 verbose("socket: %.100s", strerror(errno));
3099 continue;
3100 }
3101 if (set_nonblock(sock) == -1)
3102 fatal("%s: set_nonblock(%d)", __func__, sock);
3103 if (connect(sock, cctx->ai->ai_addr,
3104 cctx->ai->ai_addrlen) == -1 && errno != EINPROGRESS) {
3105 debug("connect_next: host %.100s ([%.100s]:%s): "
3106 "%.100s", cctx->host, ntop, strport,
3107 strerror(errno));
3108 saved_errno = errno;
3109 close(sock);
3110 errno = saved_errno;
3111 continue; /* fail -- try next */
3112 }
3113 debug("connect_next: host %.100s ([%.100s]:%s) "
3114 "in progress, fd=%d", cctx->host, ntop, strport, sock);
3115 cctx->ai = cctx->ai->ai_next;
3116 set_nodelay(sock);
3117 return sock;
3118 }
3119 return -1;
3120 }
3121
3122 static void
3123 channel_connect_ctx_free(struct channel_connect *cctx)
3124 {
3125 xfree(cctx->host);
3126 if (cctx->aitop)
3127 freeaddrinfo(cctx->aitop);
3128 bzero(cctx, sizeof(*cctx));
3129 cctx->host = NULL;
3130 cctx->ai = cctx->aitop = NULL;
3131 }
3132
3133 /* Return CONNECTING channel to remote host, port */
3134 static Channel *
3135 connect_to(const char *host, u_short port, char *ctype, char *rname)
3136 {
3137 struct addrinfo hints;
3138 int gaierr;
3139 int sock = -1;
3140 char strport[NI_MAXSERV];
3141 struct channel_connect cctx;
3142 Channel *c;
3143
3144 memset(&cctx, 0, sizeof(cctx));
3145 memset(&hints, 0, sizeof(hints));
3146 hints.ai_family = IPv4or6;
3147 hints.ai_socktype = SOCK_STREAM;
3148 snprintf(strport, sizeof strport, "%d", port);
3149 if ((gaierr = getaddrinfo(host, strport, &hints, &cctx.aitop)) != 0) {
3150 error("connect_to %.100s: unknown host (%s)", host,
3151 ssh_gai_strerror(gaierr));
3152 return NULL;
3153 }
3154
3155 cctx.host = xstrdup(host);
3156 cctx.port = port;
3157 cctx.ai = cctx.aitop;
3158
3159 if ((sock = connect_next(&cctx)) == -1) {
3160 error("connect to %.100s port %d failed: %s",
3161 host, port, strerror(errno));
3162 channel_connect_ctx_free(&cctx);
3163 return NULL;
3164 }
3165 c = channel_new(ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1,
3166 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1);
3167 c->connect_ctx = cctx;
3168 return c;
3169 }
3170
3171 Channel *
3172 channel_connect_by_listen_address(u_short listen_port, char *ctype, char *rname)
3173 {
3174 int i;
3175
3176 for (i = 0; i < num_permitted_opens; i++) {
3177 if (permitted_opens[i].host_to_connect != NULL &&
3178 permitted_opens[i].listen_port == listen_port) {
3179 return connect_to(
3180 permitted_opens[i].host_to_connect,
3181 permitted_opens[i].port_to_connect, ctype, rname);
3182 }
3183 }
3184 error("WARNING: Server requests forwarding for unknown listen_port %d",
3185 listen_port);
3186 return NULL;
3187 }
3188
3189 /* Check if connecting to that port is permitted and connect. */
3190 Channel *
3191 channel_connect_to(const char *host, u_short port, char *ctype, char *rname)
3192 {
3193 int i, permit, permit_adm = 1;
3194
3195 permit = all_opens_permitted;
3196 if (!permit) {
3197 for (i = 0; i < num_permitted_opens; i++)
3198 if (permitted_opens[i].host_to_connect != NULL &&
3199 permitted_opens[i].port_to_connect == port &&
3200 strcmp(permitted_opens[i].host_to_connect, host) == 0)
3201 permit = 1;
3202 }
3203
3204 if (num_adm_permitted_opens > 0) {
3205 permit_adm = 0;
3206 for (i = 0; i < num_adm_permitted_opens; i++)
3207 if (permitted_adm_opens[i].host_to_connect != NULL &&
3208 permitted_adm_opens[i].port_to_connect == port &&
3209 strcmp(permitted_adm_opens[i].host_to_connect, host)
3210 == 0)
3211 permit_adm = 1;
3212 }
3213
3214 if (!permit || !permit_adm) {
3215 logit("Received request to connect to host %.100s port %d, "
3216 "but the request was denied.", host, port);
3217 return NULL;
3218 }
3219 return connect_to(host, port, ctype, rname);
3220 }
3221
3222 void
3223 channel_send_window_changes(void)
3224 {
3225 u_int i;
3226 struct winsize ws;
3227
3228 for (i = 0; i < channels_alloc; i++) {
3229 if (channels[i] == NULL || !channels[i]->client_tty ||
3230 channels[i]->type != SSH_CHANNEL_OPEN)
3231 continue;
3232 if (ioctl(channels[i]->rfd, TIOCGWINSZ, &ws) < 0)
3233 continue;
3234 channel_request_start(i, "window-change", 0);
3235 packet_put_int((u_int)ws.ws_col);
3236 packet_put_int((u_int)ws.ws_row);
3237 packet_put_int((u_int)ws.ws_xpixel);
3238 packet_put_int((u_int)ws.ws_ypixel);
3239 packet_send();
3240 }
3241 }
3242
3243 /* -- X11 forwarding */
3244
3245 /*
3246 * Creates an internet domain socket for listening for X11 connections.
3247 * Returns 0 and a suitable display number for the DISPLAY variable
3248 * stored in display_numberp , or -1 if an error occurs.
3249 */
3250 int
3251 x11_create_display_inet(int x11_display_offset, int x11_use_localhost,
3252 int single_connection, u_int *display_numberp, int **chanids)
3253 {
3254 Channel *nc = NULL;
3255 int display_number, sock;
3256 u_short port;
3257 struct addrinfo hints, *ai, *aitop;
3258 char strport[NI_MAXSERV];
3259 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
3260
3261 if (chanids == NULL)
3262 return -1;
3263
3264 for (display_number = x11_display_offset;
3265 display_number < MAX_DISPLAYS;
3266 display_number++) {
3267 port = 6000 + display_number;
3268 memset(&hints, 0, sizeof(hints));
3269 hints.ai_family = IPv4or6;
3270 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE;
3271 hints.ai_socktype = SOCK_STREAM;
3272 snprintf(strport, sizeof strport, "%d", port);
3273 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
3274 error("getaddrinfo: %.100s", ssh_gai_strerror(gaierr));
3275 return -1;
3276 }
3277 for (ai = aitop; ai; ai = ai->ai_next) {
3278 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
3279 continue;
3280 sock = socket(ai->ai_family, ai->ai_socktype,
3281 ai->ai_protocol);
3282 if (sock < 0) {
3283 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)
3284 #ifdef EPFNOSUPPORT
3285 && (errno != EPFNOSUPPORT)
3286 #endif
3287 ) {
3288 error("socket: %.100s", strerror(errno));
3289 freeaddrinfo(aitop);
3290 return -1;
3291 } else {
3292 debug("x11_create_display_inet: Socket family %d not supported",
3293 ai->ai_family);
3294 continue;
3295 }
3296 }
3297 if (ai->ai_family == AF_INET6)
3298 sock_set_v6only(sock);
3299 if (x11_use_localhost)
3300 channel_set_reuseaddr(sock);
3301 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
3302 debug2("bind port %d: %.100s", port, strerror(errno));
3303 close(sock);
3304
3305 for (n = 0; n < num_socks; n++) {
3306 close(socks[n]);
3307 }
3308 num_socks = 0;
3309 break;
3310 }
3311 socks[num_socks++] = sock;
3312 if (num_socks == NUM_SOCKS)
3313 break;
3314 }
3315 freeaddrinfo(aitop);
3316 if (num_socks > 0)
3317 break;
3318 }
3319 if (display_number >= MAX_DISPLAYS) {
3320 error("Failed to allocate internet-domain X11 display socket.");
3321 return -1;
3322 }
3323 /* Start listening for connections on the socket. */
3324 for (n = 0; n < num_socks; n++) {
3325 sock = socks[n];
3326 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
3327 error("listen: %.100s", strerror(errno));
3328 close(sock);
3329 return -1;
3330 }
3331 }
3332
3333 /* Allocate a channel for each socket. */
3334 *chanids = xcalloc(num_socks + 1, sizeof(**chanids));
3335 for (n = 0; n < num_socks; n++) {
3336 sock = socks[n];
3337 nc = channel_new("x11 listener",
3338 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
3339 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
3340 0, "X11 inet listener", 1);
3341 nc->single_connection = single_connection;
3342 (*chanids)[n] = nc->self;
3343 }
3344 (*chanids)[n] = -1;
3345
3346 /* Return the display number for the DISPLAY environment variable. */
3347 *display_numberp = display_number;
3348 return (0);
3349 }
3350
3351 static int
3352 connect_local_xsocket_path(const char *pathname)
3353 {
3354 int sock;
3355 struct sockaddr_un addr;
3356
3357 sock = socket(AF_UNIX, SOCK_STREAM, 0);
3358 if (sock < 0)
3359 error("socket: %.100s", strerror(errno));
3360 memset(&addr, 0, sizeof(addr));
3361 addr.sun_family = AF_UNIX;
3362 strlcpy(addr.sun_path, pathname, sizeof addr.sun_path);
3363 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0)
3364 return sock;
3365 close(sock);
3366 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
3367 return -1;
3368 }
3369
3370 static int
3371 connect_local_xsocket(u_int dnr)
3372 {
3373 char buf[1024];
3374 snprintf(buf, sizeof buf, _PATH_UNIX_X, dnr);
3375 return connect_local_xsocket_path(buf);
3376 }
3377
3378 int
3379 x11_connect_display(void)
3380 {
3381 u_int display_number;
3382 const char *display;
3383 char buf[1024], *cp;
3384 struct addrinfo hints, *ai, *aitop;
3385 char strport[NI_MAXSERV];
3386 int gaierr, sock = 0;
3387
3388 /* Try to open a socket for the local X server. */
3389 display = getenv("DISPLAY");
3390 if (!display) {
3391 error("DISPLAY not set.");
3392 return -1;
3393 }
3394 /*
3395 * Now we decode the value of the DISPLAY variable and make a
3396 * connection to the real X server.
3397 */
3398
3399 /* Check if the display is from launchd. */
3400 #ifdef __APPLE__
3401 if (strncmp(display, "/tmp/launch", 11) == 0) {
3402 sock = connect_local_xsocket_path(display);
3403 if (sock < 0)
3404 return -1;
3405
3406 /* OK, we now have a connection to the display. */
3407 return sock;
3408 }
3409 #endif
3410 /*
3411 * Check if it is a unix domain socket. Unix domain displays are in
3412 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
3413 */
3414 if (strncmp(display, "unix:", 5) == 0 ||
3415 display[0] == ':') {
3416 /* Connect to the unix domain socket. */
3417 if (sscanf(strrchr(display, ':') + 1, "%u", &display_number) != 1) {
3418 error("Could not parse display number from DISPLAY: %.100s",
3419 display);
3420 return -1;
3421 }
3422 /* Create a socket. */
3423 sock = connect_local_xsocket(display_number);
3424 if (sock < 0)
3425 return -1;
3426
3427 /* OK, we now have a connection to the display. */
3428 return sock;
3429 }
3430 /*
3431 * Connect to an inet socket. The DISPLAY value is supposedly
3432 * hostname:d[.s], where hostname may also be numeric IP address.
3433 */
3434 strlcpy(buf, display, sizeof(buf));
3435 cp = strchr(buf, ':');
3436 if (!cp) {
3437 error("Could not find ':' in DISPLAY: %.100s", display);
3438 return -1;
3439 }
3440 *cp = 0;
3441 /* buf now contains the host name. But first we parse the display number. */
3442 if (sscanf(cp + 1, "%u", &display_number) != 1) {
3443 error("Could not parse display number from DISPLAY: %.100s",
3444 display);
3445 return -1;
3446 }
3447
3448 /* Look up the host address */
3449 memset(&hints, 0, sizeof(hints));
3450 hints.ai_family = IPv4or6;
3451 hints.ai_socktype = SOCK_STREAM;
3452 snprintf(strport, sizeof strport, "%u", 6000 + display_number);
3453 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
3454 error("%.100s: unknown host. (%s)", buf,
3455 ssh_gai_strerror(gaierr));
3456 return -1;
3457 }
3458 for (ai = aitop; ai; ai = ai->ai_next) {
3459 /* Create a socket. */
3460 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
3461 if (sock < 0) {
3462 debug2("socket: %.100s", strerror(errno));
3463 continue;
3464 }
3465 /* Connect it to the display. */
3466 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
3467 debug2("connect %.100s port %u: %.100s", buf,
3468 6000 + display_number, strerror(errno));
3469 close(sock);
3470 continue;
3471 }
3472 /* Success */
3473 break;
3474 }
3475 freeaddrinfo(aitop);
3476 if (!ai) {
3477 error("connect %.100s port %u: %.100s", buf, 6000 + display_number,
3478 strerror(errno));
3479 return -1;
3480 }
3481 set_nodelay(sock);
3482 return sock;
3483 }
3484
3485 /*
3486 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
3487 * the remote channel number. We should do whatever we want, and respond
3488 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
3489 */
3490
3491 /* ARGSUSED */
3492 void
3493 x11_input_open(int type, u_int32_t seq, void *ctxt)
3494 {
3495 Channel *c = NULL;
3496 int remote_id, sock = 0;
3497 char *remote_host;
3498
3499 debug("Received X11 open request.");
3500
3501 remote_id = packet_get_int();
3502
3503 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
3504 remote_host = packet_get_string(NULL);
3505 } else {
3506 remote_host = xstrdup("unknown (remote did not supply name)");
3507 }
3508 packet_check_eom();
3509
3510 /* Obtain a connection to the real X display. */
3511 sock = x11_connect_display();
3512 if (sock != -1) {
3513 /* Allocate a channel for this connection. */
3514 c = channel_new("connected x11 socket",
3515 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
3516 remote_host, 1);
3517 c->remote_id = remote_id;
3518 c->force_drain = 1;
3519 }
3520 xfree(remote_host);
3521 if (c == NULL) {
3522 /* Send refusal to the remote host. */
3523 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3524 packet_put_int(remote_id);
3525 } else {
3526 /* Send a confirmation to the remote host. */
3527 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
3528 packet_put_int(remote_id);
3529 packet_put_int(c->self);
3530 }
3531 packet_send();
3532 }
3533
3534 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
3535 /* ARGSUSED */
3536 void
3537 deny_input_open(int type, u_int32_t seq, void *ctxt)
3538 {
3539 int rchan = packet_get_int();
3540
3541 switch (type) {
3542 case SSH_SMSG_AGENT_OPEN:
3543 error("Warning: ssh server tried agent forwarding.");
3544 break;
3545 case SSH_SMSG_X11_OPEN:
3546 error("Warning: ssh server tried X11 forwarding.");
3547 break;
3548 default:
3549 error("deny_input_open: type %d", type);
3550 break;
3551 }
3552 error("Warning: this is probably a break-in attempt by a malicious server.");
3553 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3554 packet_put_int(rchan);
3555 packet_send();
3556 }
3557
3558 /*
3559 * Requests forwarding of X11 connections, generates fake authentication
3560 * data, and enables authentication spoofing.
3561 * This should be called in the client only.
3562 */
3563 void
3564 x11_request_forwarding_with_spoofing(int client_session_id, const char *disp,
3565 const char *proto, const char *data)
3566 {
3567 u_int data_len = (u_int) strlen(data) / 2;
3568 u_int i, value;
3569 char *new_data;
3570 int screen_number;
3571 const char *cp;
3572 u_int32_t rnd = 0;
3573
3574 if (x11_saved_display == NULL)
3575 x11_saved_display = xstrdup(disp);
3576 else if (strcmp(disp, x11_saved_display) != 0) {
3577 error("x11_request_forwarding_with_spoofing: different "
3578 "$DISPLAY already forwarded");
3579 return;
3580 }
3581
3582 cp = strchr(disp, ':');
3583 if (cp)
3584 cp = strchr(cp, '.');
3585 if (cp)
3586 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL);
3587 else
3588 screen_number = 0;
3589
3590 if (x11_saved_proto == NULL) {
3591 /* Save protocol name. */
3592 x11_saved_proto = xstrdup(proto);
3593 /*
3594 * Extract real authentication data and generate fake data
3595 * of the same length.
3596 */
3597 x11_saved_data = xmalloc(data_len);
3598 x11_fake_data = xmalloc(data_len);
3599 for (i = 0; i < data_len; i++) {
3600 if (sscanf(data + 2 * i, "%2x", &value) != 1)
3601 fatal("x11_request_forwarding: bad "
3602 "authentication data: %.100s", data);
3603 if (i % 4 == 0)
3604 rnd = arc4random();
3605 x11_saved_data[i] = value;
3606 x11_fake_data[i] = rnd & 0xff;
3607 rnd >>= 8;
3608 }
3609 x11_saved_data_len = data_len;
3610 x11_fake_data_len = data_len;
3611 }
3612
3613 /* Convert the fake data into hex. */
3614 new_data = tohex(x11_fake_data, data_len);
3615
3616 /* Send the request packet. */
3617 if (compat20) {
3618 channel_request_start(client_session_id, "x11-req", 0);
3619 packet_put_char(0); /* XXX bool single connection */
3620 } else {
3621 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
3622 }
3623 packet_put_cstring(proto);
3624 packet_put_cstring(new_data);
3625 packet_put_int(screen_number);
3626 packet_send();
3627 packet_write_wait();
3628 xfree(new_data);
3629 }
3630
3631
3632 /* -- agent forwarding */
3633
3634 /* Sends a message to the server to request authentication fd forwarding. */
3635
3636 void
3637 auth_request_forwarding(void)
3638 {
3639 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
3640 packet_send();
3641 packet_write_wait();
3642 }
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