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- dtucker@cvs.openbsd.org 2009/11/10 04:30:45
[openssh-git.git] / channels.c
blobeb0c61d8b3be969ee81e787c9aa03443f3cc4b4d
1 /* $OpenBSD: channels.c,v 1.298 2009/11/10 04:30:44 dtucker 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[SSH_MAX_FORWARDS_PER_DIRECTION];
118
119 /* List of all permitted host/port pairs to connect by the admin. */
120 static ForwardPermission permitted_adm_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
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 /* Set the routing domain a.k.a. VRF */
167 static int channel_rdomain = -1;
168
169 /* helper */
170 static void port_open_helper(Channel *c, char *rtype);
171
172 /* non-blocking connect helpers */
173 static int connect_next(struct channel_connect *);
174 static void channel_connect_ctx_free(struct channel_connect *);
175
176 /* -- channel core */
177
178 Channel *
179 channel_by_id(int id)
180 {
181 Channel *c;
182
183 if (id < 0 || (u_int)id >= channels_alloc) {
184 logit("channel_by_id: %d: bad id", id);
185 return NULL;
186 }
187 c = channels[id];
188 if (c == NULL) {
189 logit("channel_by_id: %d: bad id: channel free", id);
190 return NULL;
191 }
192 return c;
193 }
194
195 /*
196 * Returns the channel if it is allowed to receive protocol messages.
197 * Private channels, like listening sockets, may not receive messages.
198 */
199 Channel *
200 channel_lookup(int id)
201 {
202 Channel *c;
203
204 if ((c = channel_by_id(id)) == NULL)
205 return (NULL);
206
207 switch (c->type) {
208 case SSH_CHANNEL_X11_OPEN:
209 case SSH_CHANNEL_LARVAL:
210 case SSH_CHANNEL_CONNECTING:
211 case SSH_CHANNEL_DYNAMIC:
212 case SSH_CHANNEL_OPENING:
213 case SSH_CHANNEL_OPEN:
214 case SSH_CHANNEL_INPUT_DRAINING:
215 case SSH_CHANNEL_OUTPUT_DRAINING:
216 return (c);
217 }
218 logit("Non-public channel %d, type %d.", id, c->type);
219 return (NULL);
220 }
221
222 /*
223 * Register filedescriptors for a channel, used when allocating a channel or
224 * when the channel consumer/producer is ready, e.g. shell exec'd
225 */
226 static void
227 channel_register_fds(Channel *c, int rfd, int wfd, int efd,
228 int extusage, int nonblock, int is_tty)
229 {
230 /* Update the maximum file descriptor value. */
231 channel_max_fd = MAX(channel_max_fd, rfd);
232 channel_max_fd = MAX(channel_max_fd, wfd);
233 channel_max_fd = MAX(channel_max_fd, efd);
234
235 if (rfd != -1)
236 fcntl(rfd, F_SETFD, FD_CLOEXEC);
237 if (wfd != -1 && wfd != rfd)
238 fcntl(wfd, F_SETFD, FD_CLOEXEC);
239 if (efd != -1 && efd != rfd && efd != wfd)
240 fcntl(efd, F_SETFD, FD_CLOEXEC);
241
242 c->rfd = rfd;
243 c->wfd = wfd;
244 c->sock = (rfd == wfd) ? rfd : -1;
245 c->ctl_fd = -1; /* XXX: set elsewhere */
246 c->efd = efd;
247 c->extended_usage = extusage;
248
249 if ((c->isatty = is_tty) != 0)
250 debug2("channel %d: rfd %d isatty", c->self, c->rfd);
251 c->wfd_isatty = is_tty || isatty(c->wfd);
252
253 /* enable nonblocking mode */
254 if (nonblock) {
255 if (rfd != -1)
256 set_nonblock(rfd);
257 if (wfd != -1)
258 set_nonblock(wfd);
259 if (efd != -1)
260 set_nonblock(efd);
261 }
262 }
263
264 /*
265 * Allocate a new channel object and set its type and socket. This will cause
266 * remote_name to be freed.
267 */
268 Channel *
269 channel_new(char *ctype, int type, int rfd, int wfd, int efd,
270 u_int window, u_int maxpack, int extusage, char *remote_name, int nonblock)
271 {
272 int found;
273 u_int i;
274 Channel *c;
275
276 /* Do initial allocation if this is the first call. */
277 if (channels_alloc == 0) {
278 channels_alloc = 10;
279 channels = xcalloc(channels_alloc, sizeof(Channel *));
280 for (i = 0; i < channels_alloc; i++)
281 channels[i] = NULL;
282 }
283 /* Try to find a free slot where to put the new channel. */
284 for (found = -1, i = 0; i < channels_alloc; i++)
285 if (channels[i] == NULL) {
286 /* Found a free slot. */
287 found = (int)i;
288 break;
289 }
290 if (found < 0) {
291 /* There are no free slots. Take last+1 slot and expand the array. */
292 found = channels_alloc;
293 if (channels_alloc > 10000)
294 fatal("channel_new: internal error: channels_alloc %d "
295 "too big.", channels_alloc);
296 channels = xrealloc(channels, channels_alloc + 10,
297 sizeof(Channel *));
298 channels_alloc += 10;
299 debug2("channel: expanding %d", channels_alloc);
300 for (i = found; i < channels_alloc; i++)
301 channels[i] = NULL;
302 }
303 /* Initialize and return new channel. */
304 c = channels[found] = xcalloc(1, sizeof(Channel));
305 buffer_init(&c->input);
306 buffer_init(&c->output);
307 buffer_init(&c->extended);
308 c->path = NULL;
309 c->ostate = CHAN_OUTPUT_OPEN;
310 c->istate = CHAN_INPUT_OPEN;
311 c->flags = 0;
312 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock, 0);
313 c->self = found;
314 c->type = type;
315 c->ctype = ctype;
316 c->local_window = window;
317 c->local_window_max = window;
318 c->local_consumed = 0;
319 c->local_maxpacket = maxpack;
320 c->remote_id = -1;
321 c->remote_name = xstrdup(remote_name);
322 c->remote_window = 0;
323 c->remote_maxpacket = 0;
324 c->force_drain = 0;
325 c->single_connection = 0;
326 c->detach_user = NULL;
327 c->detach_close = 0;
328 c->open_confirm = NULL;
329 c->open_confirm_ctx = NULL;
330 c->input_filter = NULL;
331 c->output_filter = NULL;
332 c->filter_ctx = NULL;
333 c->filter_cleanup = NULL;
334 TAILQ_INIT(&c->status_confirms);
335 debug("channel %d: new [%s]", found, remote_name);
336 return c;
337 }
338
339 static int
340 channel_find_maxfd(void)
341 {
342 u_int i;
343 int max = 0;
344 Channel *c;
345
346 for (i = 0; i < channels_alloc; i++) {
347 c = channels[i];
348 if (c != NULL) {
349 max = MAX(max, c->rfd);
350 max = MAX(max, c->wfd);
351 max = MAX(max, c->efd);
352 }
353 }
354 return max;
355 }
356
357 int
358 channel_close_fd(int *fdp)
359 {
360 int ret = 0, fd = *fdp;
361
362 if (fd != -1) {
363 ret = close(fd);
364 *fdp = -1;
365 if (fd == channel_max_fd)
366 channel_max_fd = channel_find_maxfd();
367 }
368 return ret;
369 }
370
371 /* Close all channel fd/socket. */
372 static void
373 channel_close_fds(Channel *c)
374 {
375 debug3("channel %d: close_fds r %d w %d e %d c %d",
376 c->self, c->rfd, c->wfd, c->efd, c->ctl_fd);
377
378 channel_close_fd(&c->sock);
379 channel_close_fd(&c->ctl_fd);
380 channel_close_fd(&c->rfd);
381 channel_close_fd(&c->wfd);
382 channel_close_fd(&c->efd);
383 }
384
385 /* Free the channel and close its fd/socket. */
386 void
387 channel_free(Channel *c)
388 {
389 char *s;
390 u_int i, n;
391 struct channel_confirm *cc;
392
393 for (n = 0, i = 0; i < channels_alloc; i++)
394 if (channels[i])
395 n++;
396 debug("channel %d: free: %s, nchannels %u", c->self,
397 c->remote_name ? c->remote_name : "???", n);
398
399 s = channel_open_message();
400 debug3("channel %d: status: %s", c->self, s);
401 xfree(s);
402
403 if (c->sock != -1)
404 shutdown(c->sock, SHUT_RDWR);
405 if (c->ctl_fd != -1)
406 shutdown(c->ctl_fd, SHUT_RDWR);
407 channel_close_fds(c);
408 buffer_free(&c->input);
409 buffer_free(&c->output);
410 buffer_free(&c->extended);
411 if (c->remote_name) {
412 xfree(c->remote_name);
413 c->remote_name = NULL;
414 }
415 if (c->path) {
416 xfree(c->path);
417 c->path = NULL;
418 }
419 while ((cc = TAILQ_FIRST(&c->status_confirms)) != NULL) {
420 if (cc->abandon_cb != NULL)
421 cc->abandon_cb(c, cc->ctx);
422 TAILQ_REMOVE(&c->status_confirms, cc, entry);
423 bzero(cc, sizeof(*cc));
424 xfree(cc);
425 }
426 if (c->filter_cleanup != NULL && c->filter_ctx != NULL)
427 c->filter_cleanup(c->self, c->filter_ctx);
428 channels[c->self] = NULL;
429 xfree(c);
430 }
431
432 void
433 channel_free_all(void)
434 {
435 u_int i;
436
437 for (i = 0; i < channels_alloc; i++)
438 if (channels[i] != NULL)
439 channel_free(channels[i]);
440 }
441
442 /*
443 * Closes the sockets/fds of all channels. This is used to close extra file
444 * descriptors after a fork.
445 */
446 void
447 channel_close_all(void)
448 {
449 u_int i;
450
451 for (i = 0; i < channels_alloc; i++)
452 if (channels[i] != NULL)
453 channel_close_fds(channels[i]);
454 }
455
456 /*
457 * Stop listening to channels.
458 */
459 void
460 channel_stop_listening(void)
461 {
462 u_int i;
463 Channel *c;
464
465 for (i = 0; i < channels_alloc; i++) {
466 c = channels[i];
467 if (c != NULL) {
468 switch (c->type) {
469 case SSH_CHANNEL_AUTH_SOCKET:
470 case SSH_CHANNEL_PORT_LISTENER:
471 case SSH_CHANNEL_RPORT_LISTENER:
472 case SSH_CHANNEL_X11_LISTENER:
473 channel_close_fd(&c->sock);
474 channel_free(c);
475 break;
476 }
477 }
478 }
479 }
480
481 /*
482 * Returns true if no channel has too much buffered data, and false if one or
483 * more channel is overfull.
484 */
485 int
486 channel_not_very_much_buffered_data(void)
487 {
488 u_int i;
489 Channel *c;
490
491 for (i = 0; i < channels_alloc; i++) {
492 c = channels[i];
493 if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
494 #if 0
495 if (!compat20 &&
496 buffer_len(&c->input) > packet_get_maxsize()) {
497 debug2("channel %d: big input buffer %d",
498 c->self, buffer_len(&c->input));
499 return 0;
500 }
501 #endif
502 if (buffer_len(&c->output) > packet_get_maxsize()) {
503 debug2("channel %d: big output buffer %u > %u",
504 c->self, buffer_len(&c->output),
505 packet_get_maxsize());
506 return 0;
507 }
508 }
509 }
510 return 1;
511 }
512
513 /* Returns true if any channel is still open. */
514 int
515 channel_still_open(void)
516 {
517 u_int i;
518 Channel *c;
519
520 for (i = 0; i < channels_alloc; i++) {
521 c = channels[i];
522 if (c == NULL)
523 continue;
524 switch (c->type) {
525 case SSH_CHANNEL_X11_LISTENER:
526 case SSH_CHANNEL_PORT_LISTENER:
527 case SSH_CHANNEL_RPORT_LISTENER:
528 case SSH_CHANNEL_CLOSED:
529 case SSH_CHANNEL_AUTH_SOCKET:
530 case SSH_CHANNEL_DYNAMIC:
531 case SSH_CHANNEL_CONNECTING:
532 case SSH_CHANNEL_ZOMBIE:
533 continue;
534 case SSH_CHANNEL_LARVAL:
535 if (!compat20)
536 fatal("cannot happen: SSH_CHANNEL_LARVAL");
537 continue;
538 case SSH_CHANNEL_OPENING:
539 case SSH_CHANNEL_OPEN:
540 case SSH_CHANNEL_X11_OPEN:
541 return 1;
542 case SSH_CHANNEL_INPUT_DRAINING:
543 case SSH_CHANNEL_OUTPUT_DRAINING:
544 if (!compat13)
545 fatal("cannot happen: OUT_DRAIN");
546 return 1;
547 default:
548 fatal("channel_still_open: bad channel type %d", c->type);
549 /* NOTREACHED */
550 }
551 }
552 return 0;
553 }
554
555 /* Returns the id of an open channel suitable for keepaliving */
556 int
557 channel_find_open(void)
558 {
559 u_int i;
560 Channel *c;
561
562 for (i = 0; i < channels_alloc; i++) {
563 c = channels[i];
564 if (c == NULL || c->remote_id < 0)
565 continue;
566 switch (c->type) {
567 case SSH_CHANNEL_CLOSED:
568 case SSH_CHANNEL_DYNAMIC:
569 case SSH_CHANNEL_X11_LISTENER:
570 case SSH_CHANNEL_PORT_LISTENER:
571 case SSH_CHANNEL_RPORT_LISTENER:
572 case SSH_CHANNEL_OPENING:
573 case SSH_CHANNEL_CONNECTING:
574 case SSH_CHANNEL_ZOMBIE:
575 continue;
576 case SSH_CHANNEL_LARVAL:
577 case SSH_CHANNEL_AUTH_SOCKET:
578 case SSH_CHANNEL_OPEN:
579 case SSH_CHANNEL_X11_OPEN:
580 return i;
581 case SSH_CHANNEL_INPUT_DRAINING:
582 case SSH_CHANNEL_OUTPUT_DRAINING:
583 if (!compat13)
584 fatal("cannot happen: OUT_DRAIN");
585 return i;
586 default:
587 fatal("channel_find_open: bad channel type %d", c->type);
588 /* NOTREACHED */
589 }
590 }
591 return -1;
592 }
593
594
595 /*
596 * Returns a message describing the currently open forwarded connections,
597 * suitable for sending to the client. The message contains crlf pairs for
598 * newlines.
599 */
600 char *
601 channel_open_message(void)
602 {
603 Buffer buffer;
604 Channel *c;
605 char buf[1024], *cp;
606 u_int i;
607
608 buffer_init(&buffer);
609 snprintf(buf, sizeof buf, "The following connections are open:\r\n");
610 buffer_append(&buffer, buf, strlen(buf));
611 for (i = 0; i < channels_alloc; i++) {
612 c = channels[i];
613 if (c == NULL)
614 continue;
615 switch (c->type) {
616 case SSH_CHANNEL_X11_LISTENER:
617 case SSH_CHANNEL_PORT_LISTENER:
618 case SSH_CHANNEL_RPORT_LISTENER:
619 case SSH_CHANNEL_CLOSED:
620 case SSH_CHANNEL_AUTH_SOCKET:
621 case SSH_CHANNEL_ZOMBIE:
622 continue;
623 case SSH_CHANNEL_LARVAL:
624 case SSH_CHANNEL_OPENING:
625 case SSH_CHANNEL_CONNECTING:
626 case SSH_CHANNEL_DYNAMIC:
627 case SSH_CHANNEL_OPEN:
628 case SSH_CHANNEL_X11_OPEN:
629 case SSH_CHANNEL_INPUT_DRAINING:
630 case SSH_CHANNEL_OUTPUT_DRAINING:
631 snprintf(buf, sizeof buf,
632 " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d cfd %d)\r\n",
633 c->self, c->remote_name,
634 c->type, c->remote_id,
635 c->istate, buffer_len(&c->input),
636 c->ostate, buffer_len(&c->output),
637 c->rfd, c->wfd, c->ctl_fd);
638 buffer_append(&buffer, buf, strlen(buf));
639 continue;
640 default:
641 fatal("channel_open_message: bad channel type %d", c->type);
642 /* NOTREACHED */
643 }
644 }
645 buffer_append(&buffer, "\0", 1);
646 cp = xstrdup(buffer_ptr(&buffer));
647 buffer_free(&buffer);
648 return cp;
649 }
650
651 void
652 channel_send_open(int id)
653 {
654 Channel *c = channel_lookup(id);
655
656 if (c == NULL) {
657 logit("channel_send_open: %d: bad id", id);
658 return;
659 }
660 debug2("channel %d: send open", id);
661 packet_start(SSH2_MSG_CHANNEL_OPEN);
662 packet_put_cstring(c->ctype);
663 packet_put_int(c->self);
664 packet_put_int(c->local_window);
665 packet_put_int(c->local_maxpacket);
666 packet_send();
667 }
668
669 void
670 channel_request_start(int id, char *service, int wantconfirm)
671 {
672 Channel *c = channel_lookup(id);
673
674 if (c == NULL) {
675 logit("channel_request_start: %d: unknown channel id", id);
676 return;
677 }
678 debug2("channel %d: request %s confirm %d", id, service, wantconfirm);
679 packet_start(SSH2_MSG_CHANNEL_REQUEST);
680 packet_put_int(c->remote_id);
681 packet_put_cstring(service);
682 packet_put_char(wantconfirm);
683 }
684
685 void
686 channel_register_status_confirm(int id, channel_confirm_cb *cb,
687 channel_confirm_abandon_cb *abandon_cb, void *ctx)
688 {
689 struct channel_confirm *cc;
690 Channel *c;
691
692 if ((c = channel_lookup(id)) == NULL)
693 fatal("channel_register_expect: %d: bad id", id);
694
695 cc = xmalloc(sizeof(*cc));
696 cc->cb = cb;
697 cc->abandon_cb = abandon_cb;
698 cc->ctx = ctx;
699 TAILQ_INSERT_TAIL(&c->status_confirms, cc, entry);
700 }
701
702 void
703 channel_register_open_confirm(int id, channel_callback_fn *fn, void *ctx)
704 {
705 Channel *c = channel_lookup(id);
706
707 if (c == NULL) {
708 logit("channel_register_open_confirm: %d: bad id", id);
709 return;
710 }
711 c->open_confirm = fn;
712 c->open_confirm_ctx = ctx;
713 }
714
715 void
716 channel_register_cleanup(int id, channel_callback_fn *fn, int do_close)
717 {
718 Channel *c = channel_by_id(id);
719
720 if (c == NULL) {
721 logit("channel_register_cleanup: %d: bad id", id);
722 return;
723 }
724 c->detach_user = fn;
725 c->detach_close = do_close;
726 }
727
728 void
729 channel_cancel_cleanup(int id)
730 {
731 Channel *c = channel_by_id(id);
732
733 if (c == NULL) {
734 logit("channel_cancel_cleanup: %d: bad id", id);
735 return;
736 }
737 c->detach_user = NULL;
738 c->detach_close = 0;
739 }
740
741 void
742 channel_register_filter(int id, channel_infilter_fn *ifn,
743 channel_outfilter_fn *ofn, channel_filter_cleanup_fn *cfn, void *ctx)
744 {
745 Channel *c = channel_lookup(id);
746
747 if (c == NULL) {
748 logit("channel_register_filter: %d: bad id", id);
749 return;
750 }
751 c->input_filter = ifn;
752 c->output_filter = ofn;
753 c->filter_ctx = ctx;
754 c->filter_cleanup = cfn;
755 }
756
757 void
758 channel_set_fds(int id, int rfd, int wfd, int efd,
759 int extusage, int nonblock, int is_tty, u_int window_max)
760 {
761 Channel *c = channel_lookup(id);
762
763 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
764 fatal("channel_activate for non-larval channel %d.", id);
765 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock, is_tty);
766 c->type = SSH_CHANNEL_OPEN;
767 c->local_window = c->local_window_max = window_max;
768 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
769 packet_put_int(c->remote_id);
770 packet_put_int(c->local_window);
771 packet_send();
772 }
773
774 /*
775 * 'channel_pre*' are called just before select() to add any bits relevant to
776 * channels in the select bitmasks.
777 */
778 /*
779 * 'channel_post*': perform any appropriate operations for channels which
780 * have events pending.
781 */
782 typedef void chan_fn(Channel *c, fd_set *readset, fd_set *writeset);
783 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
784 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
785
786 /* ARGSUSED */
787 static void
788 channel_pre_listener(Channel *c, fd_set *readset, fd_set *writeset)
789 {
790 FD_SET(c->sock, readset);
791 }
792
793 /* ARGSUSED */
794 static void
795 channel_pre_connecting(Channel *c, fd_set *readset, fd_set *writeset)
796 {
797 debug3("channel %d: waiting for connection", c->self);
798 FD_SET(c->sock, writeset);
799 }
800
801 static void
802 channel_pre_open_13(Channel *c, fd_set *readset, fd_set *writeset)
803 {
804 if (buffer_len(&c->input) < packet_get_maxsize())
805 FD_SET(c->sock, readset);
806 if (buffer_len(&c->output) > 0)
807 FD_SET(c->sock, writeset);
808 }
809
810 static void
811 channel_pre_open(Channel *c, fd_set *readset, fd_set *writeset)
812 {
813 u_int limit = compat20 ? c->remote_window : packet_get_maxsize();
814
815 if (c->istate == CHAN_INPUT_OPEN &&
816 limit > 0 &&
817 buffer_len(&c->input) < limit &&
818 buffer_check_alloc(&c->input, CHAN_RBUF))
819 FD_SET(c->rfd, readset);
820 if (c->ostate == CHAN_OUTPUT_OPEN ||
821 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
822 if (buffer_len(&c->output) > 0) {
823 FD_SET(c->wfd, writeset);
824 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
825 if (CHANNEL_EFD_OUTPUT_ACTIVE(c))
826 debug2("channel %d: obuf_empty delayed efd %d/(%d)",
827 c->self, c->efd, buffer_len(&c->extended));
828 else
829 chan_obuf_empty(c);
830 }
831 }
832 /** XXX check close conditions, too */
833 if (compat20 && c->efd != -1 &&
834 !(c->istate == CHAN_INPUT_CLOSED && c->ostate == CHAN_OUTPUT_CLOSED)) {
835 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
836 buffer_len(&c->extended) > 0)
837 FD_SET(c->efd, writeset);
838 else if (!(c->flags & CHAN_EOF_SENT) &&
839 c->extended_usage == CHAN_EXTENDED_READ &&
840 buffer_len(&c->extended) < c->remote_window)
841 FD_SET(c->efd, readset);
842 }
843 /* XXX: What about efd? races? */
844 if (compat20 && c->ctl_fd != -1 &&
845 c->istate == CHAN_INPUT_OPEN && c->ostate == CHAN_OUTPUT_OPEN)
846 FD_SET(c->ctl_fd, readset);
847 }
848
849 /* ARGSUSED */
850 static void
851 channel_pre_input_draining(Channel *c, fd_set *readset, fd_set *writeset)
852 {
853 if (buffer_len(&c->input) == 0) {
854 packet_start(SSH_MSG_CHANNEL_CLOSE);
855 packet_put_int(c->remote_id);
856 packet_send();
857 c->type = SSH_CHANNEL_CLOSED;
858 debug2("channel %d: closing after input drain.", c->self);
859 }
860 }
861
862 /* ARGSUSED */
863 static void
864 channel_pre_output_draining(Channel *c, fd_set *readset, fd_set *writeset)
865 {
866 if (buffer_len(&c->output) == 0)
867 chan_mark_dead(c);
868 else
869 FD_SET(c->sock, writeset);
870 }
871
872 /*
873 * This is a special state for X11 authentication spoofing. An opened X11
874 * connection (when authentication spoofing is being done) remains in this
875 * state until the first packet has been completely read. The authentication
876 * data in that packet is then substituted by the real data if it matches the
877 * fake data, and the channel is put into normal mode.
878 * XXX All this happens at the client side.
879 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
880 */
881 static int
882 x11_open_helper(Buffer *b)
883 {
884 u_char *ucp;
885 u_int proto_len, data_len;
886
887 /* Check if the fixed size part of the packet is in buffer. */
888 if (buffer_len(b) < 12)
889 return 0;
890
891 /* Parse the lengths of variable-length fields. */
892 ucp = buffer_ptr(b);
893 if (ucp[0] == 0x42) { /* Byte order MSB first. */
894 proto_len = 256 * ucp[6] + ucp[7];
895 data_len = 256 * ucp[8] + ucp[9];
896 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
897 proto_len = ucp[6] + 256 * ucp[7];
898 data_len = ucp[8] + 256 * ucp[9];
899 } else {
900 debug2("Initial X11 packet contains bad byte order byte: 0x%x",
901 ucp[0]);
902 return -1;
903 }
904
905 /* Check if the whole packet is in buffer. */
906 if (buffer_len(b) <
907 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
908 return 0;
909
910 /* Check if authentication protocol matches. */
911 if (proto_len != strlen(x11_saved_proto) ||
912 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
913 debug2("X11 connection uses different authentication protocol.");
914 return -1;
915 }
916 /* Check if authentication data matches our fake data. */
917 if (data_len != x11_fake_data_len ||
918 memcmp(ucp + 12 + ((proto_len + 3) & ~3),
919 x11_fake_data, x11_fake_data_len) != 0) {
920 debug2("X11 auth data does not match fake data.");
921 return -1;
922 }
923 /* Check fake data length */
924 if (x11_fake_data_len != x11_saved_data_len) {
925 error("X11 fake_data_len %d != saved_data_len %d",
926 x11_fake_data_len, x11_saved_data_len);
927 return -1;
928 }
929 /*
930 * Received authentication protocol and data match
931 * our fake data. Substitute the fake data with real
932 * data.
933 */
934 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
935 x11_saved_data, x11_saved_data_len);
936 return 1;
937 }
938
939 static void
940 channel_pre_x11_open_13(Channel *c, fd_set *readset, fd_set *writeset)
941 {
942 int ret = x11_open_helper(&c->output);
943
944 if (ret == 1) {
945 /* Start normal processing for the channel. */
946 c->type = SSH_CHANNEL_OPEN;
947 channel_pre_open_13(c, readset, writeset);
948 } else if (ret == -1) {
949 /*
950 * We have received an X11 connection that has bad
951 * authentication information.
952 */
953 logit("X11 connection rejected because of wrong authentication.");
954 buffer_clear(&c->input);
955 buffer_clear(&c->output);
956 channel_close_fd(&c->sock);
957 c->sock = -1;
958 c->type = SSH_CHANNEL_CLOSED;
959 packet_start(SSH_MSG_CHANNEL_CLOSE);
960 packet_put_int(c->remote_id);
961 packet_send();
962 }
963 }
964
965 static void
966 channel_pre_x11_open(Channel *c, fd_set *readset, fd_set *writeset)
967 {
968 int ret = x11_open_helper(&c->output);
969
970 /* c->force_drain = 1; */
971
972 if (ret == 1) {
973 c->type = SSH_CHANNEL_OPEN;
974 channel_pre_open(c, readset, writeset);
975 } else if (ret == -1) {
976 logit("X11 connection rejected because of wrong authentication.");
977 debug2("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
978 chan_read_failed(c);
979 buffer_clear(&c->input);
980 chan_ibuf_empty(c);
981 buffer_clear(&c->output);
982 /* for proto v1, the peer will send an IEOF */
983 if (compat20)
984 chan_write_failed(c);
985 else
986 c->type = SSH_CHANNEL_OPEN;
987 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
988 }
989 }
990
991 /* try to decode a socks4 header */
992 /* ARGSUSED */
993 static int
994 channel_decode_socks4(Channel *c, fd_set *readset, fd_set *writeset)
995 {
996 char *p, *host;
997 u_int len, have, i, found, need;
998 char username[256];
999 struct {
1000 u_int8_t version;
1001 u_int8_t command;
1002 u_int16_t dest_port;
1003 struct in_addr dest_addr;
1004 } s4_req, s4_rsp;
1005
1006 debug2("channel %d: decode socks4", c->self);
1007
1008 have = buffer_len(&c->input);
1009 len = sizeof(s4_req);
1010 if (have < len)
1011 return 0;
1012 p = buffer_ptr(&c->input);
1013
1014 need = 1;
1015 /* SOCKS4A uses an invalid IP address 0.0.0.x */
1016 if (p[4] == 0 && p[5] == 0 && p[6] == 0 && p[7] != 0) {
1017 debug2("channel %d: socks4a request", c->self);
1018 /* ... and needs an extra string (the hostname) */
1019 need = 2;
1020 }
1021 /* Check for terminating NUL on the string(s) */
1022 for (found = 0, i = len; i < have; i++) {
1023 if (p[i] == '\0') {
1024 found++;
1025 if (found == need)
1026 break;
1027 }
1028 if (i > 1024) {
1029 /* the peer is probably sending garbage */
1030 debug("channel %d: decode socks4: too long",
1031 c->self);
1032 return -1;
1033 }
1034 }
1035 if (found < need)
1036 return 0;
1037 buffer_get(&c->input, (char *)&s4_req.version, 1);
1038 buffer_get(&c->input, (char *)&s4_req.command, 1);
1039 buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
1040 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
1041 have = buffer_len(&c->input);
1042 p = buffer_ptr(&c->input);
1043 len = strlen(p);
1044 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
1045 len++; /* trailing '\0' */
1046 if (len > have)
1047 fatal("channel %d: decode socks4: len %d > have %d",
1048 c->self, len, have);
1049 strlcpy(username, p, sizeof(username));
1050 buffer_consume(&c->input, len);
1051
1052 if (c->path != NULL) {
1053 xfree(c->path);
1054 c->path = NULL;
1055 }
1056 if (need == 1) { /* SOCKS4: one string */
1057 host = inet_ntoa(s4_req.dest_addr);
1058 c->path = xstrdup(host);
1059 } else { /* SOCKS4A: two strings */
1060 have = buffer_len(&c->input);
1061 p = buffer_ptr(&c->input);
1062 len = strlen(p);
1063 debug2("channel %d: decode socks4a: host %s/%d",
1064 c->self, p, len);
1065 len++; /* trailing '\0' */
1066 if (len > have)
1067 fatal("channel %d: decode socks4a: len %d > have %d",
1068 c->self, len, have);
1069 if (len > NI_MAXHOST) {
1070 error("channel %d: hostname \"%.100s\" too long",
1071 c->self, p);
1072 return -1;
1073 }
1074 c->path = xstrdup(p);
1075 buffer_consume(&c->input, len);
1076 }
1077 c->host_port = ntohs(s4_req.dest_port);
1078
1079 debug2("channel %d: dynamic request: socks4 host %s port %u command %u",
1080 c->self, c->path, c->host_port, s4_req.command);
1081
1082 if (s4_req.command != 1) {
1083 debug("channel %d: cannot handle: %s cn %d",
1084 c->self, need == 1 ? "SOCKS4" : "SOCKS4A", s4_req.command);
1085 return -1;
1086 }
1087 s4_rsp.version = 0; /* vn: 0 for reply */
1088 s4_rsp.command = 90; /* cd: req granted */
1089 s4_rsp.dest_port = 0; /* ignored */
1090 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
1091 buffer_append(&c->output, &s4_rsp, sizeof(s4_rsp));
1092 return 1;
1093 }
1094
1095 /* try to decode a socks5 header */
1096 #define SSH_SOCKS5_AUTHDONE 0x1000
1097 #define SSH_SOCKS5_NOAUTH 0x00
1098 #define SSH_SOCKS5_IPV4 0x01
1099 #define SSH_SOCKS5_DOMAIN 0x03
1100 #define SSH_SOCKS5_IPV6 0x04
1101 #define SSH_SOCKS5_CONNECT 0x01
1102 #define SSH_SOCKS5_SUCCESS 0x00
1103
1104 /* ARGSUSED */
1105 static int
1106 channel_decode_socks5(Channel *c, fd_set *readset, fd_set *writeset)
1107 {
1108 struct {
1109 u_int8_t version;
1110 u_int8_t command;
1111 u_int8_t reserved;
1112 u_int8_t atyp;
1113 } s5_req, s5_rsp;
1114 u_int16_t dest_port;
1115 u_char *p, dest_addr[255+1], ntop[INET6_ADDRSTRLEN];
1116 u_int have, need, i, found, nmethods, addrlen, af;
1117
1118 debug2("channel %d: decode socks5", c->self);
1119 p = buffer_ptr(&c->input);
1120 if (p[0] != 0x05)
1121 return -1;
1122 have = buffer_len(&c->input);
1123 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) {
1124 /* format: ver | nmethods | methods */
1125 if (have < 2)
1126 return 0;
1127 nmethods = p[1];
1128 if (have < nmethods + 2)
1129 return 0;
1130 /* look for method: "NO AUTHENTICATION REQUIRED" */
1131 for (found = 0, i = 2; i < nmethods + 2; i++) {
1132 if (p[i] == SSH_SOCKS5_NOAUTH) {
1133 found = 1;
1134 break;
1135 }
1136 }
1137 if (!found) {
1138 debug("channel %d: method SSH_SOCKS5_NOAUTH not found",
1139 c->self);
1140 return -1;
1141 }
1142 buffer_consume(&c->input, nmethods + 2);
1143 buffer_put_char(&c->output, 0x05); /* version */
1144 buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH); /* method */
1145 FD_SET(c->sock, writeset);
1146 c->flags |= SSH_SOCKS5_AUTHDONE;
1147 debug2("channel %d: socks5 auth done", c->self);
1148 return 0; /* need more */
1149 }
1150 debug2("channel %d: socks5 post auth", c->self);
1151 if (have < sizeof(s5_req)+1)
1152 return 0; /* need more */
1153 memcpy(&s5_req, p, sizeof(s5_req));
1154 if (s5_req.version != 0x05 ||
1155 s5_req.command != SSH_SOCKS5_CONNECT ||
1156 s5_req.reserved != 0x00) {
1157 debug2("channel %d: only socks5 connect supported", c->self);
1158 return -1;
1159 }
1160 switch (s5_req.atyp){
1161 case SSH_SOCKS5_IPV4:
1162 addrlen = 4;
1163 af = AF_INET;
1164 break;
1165 case SSH_SOCKS5_DOMAIN:
1166 addrlen = p[sizeof(s5_req)];
1167 af = -1;
1168 break;
1169 case SSH_SOCKS5_IPV6:
1170 addrlen = 16;
1171 af = AF_INET6;
1172 break;
1173 default:
1174 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp);
1175 return -1;
1176 }
1177 need = sizeof(s5_req) + addrlen + 2;
1178 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1179 need++;
1180 if (have < need)
1181 return 0;
1182 buffer_consume(&c->input, sizeof(s5_req));
1183 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1184 buffer_consume(&c->input, 1); /* host string length */
1185 buffer_get(&c->input, (char *)&dest_addr, addrlen);
1186 buffer_get(&c->input, (char *)&dest_port, 2);
1187 dest_addr[addrlen] = '\0';
1188 if (c->path != NULL) {
1189 xfree(c->path);
1190 c->path = NULL;
1191 }
1192 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) {
1193 if (addrlen >= NI_MAXHOST) {
1194 error("channel %d: dynamic request: socks5 hostname "
1195 "\"%.100s\" too long", c->self, dest_addr);
1196 return -1;
1197 }
1198 c->path = xstrdup(dest_addr);
1199 } else {
1200 if (inet_ntop(af, dest_addr, ntop, sizeof(ntop)) == NULL)
1201 return -1;
1202 c->path = xstrdup(ntop);
1203 }
1204 c->host_port = ntohs(dest_port);
1205
1206 debug2("channel %d: dynamic request: socks5 host %s port %u command %u",
1207 c->self, c->path, c->host_port, s5_req.command);
1208
1209 s5_rsp.version = 0x05;
1210 s5_rsp.command = SSH_SOCKS5_SUCCESS;
1211 s5_rsp.reserved = 0; /* ignored */
1212 s5_rsp.atyp = SSH_SOCKS5_IPV4;
1213 ((struct in_addr *)&dest_addr)->s_addr = INADDR_ANY;
1214 dest_port = 0; /* ignored */
1215
1216 buffer_append(&c->output, &s5_rsp, sizeof(s5_rsp));
1217 buffer_append(&c->output, &dest_addr, sizeof(struct in_addr));
1218 buffer_append(&c->output, &dest_port, sizeof(dest_port));
1219 return 1;
1220 }
1221
1222 /* dynamic port forwarding */
1223 static void
1224 channel_pre_dynamic(Channel *c, fd_set *readset, fd_set *writeset)
1225 {
1226 u_char *p;
1227 u_int have;
1228 int ret;
1229
1230 have = buffer_len(&c->input);
1231 c->delayed = 0;
1232 debug2("channel %d: pre_dynamic: have %d", c->self, have);
1233 /* buffer_dump(&c->input); */
1234 /* check if the fixed size part of the packet is in buffer. */
1235 if (have < 3) {
1236 /* need more */
1237 FD_SET(c->sock, readset);
1238 return;
1239 }
1240 /* try to guess the protocol */
1241 p = buffer_ptr(&c->input);
1242 switch (p[0]) {
1243 case 0x04:
1244 ret = channel_decode_socks4(c, readset, writeset);
1245 break;
1246 case 0x05:
1247 ret = channel_decode_socks5(c, readset, writeset);
1248 break;
1249 default:
1250 ret = -1;
1251 break;
1252 }
1253 if (ret < 0) {
1254 chan_mark_dead(c);
1255 } else if (ret == 0) {
1256 debug2("channel %d: pre_dynamic: need more", c->self);
1257 /* need more */
1258 FD_SET(c->sock, readset);
1259 } else {
1260 /* switch to the next state */
1261 c->type = SSH_CHANNEL_OPENING;
1262 port_open_helper(c, "direct-tcpip");
1263 }
1264 }
1265
1266 /* This is our fake X11 server socket. */
1267 /* ARGSUSED */
1268 static void
1269 channel_post_x11_listener(Channel *c, fd_set *readset, fd_set *writeset)
1270 {
1271 Channel *nc;
1272 struct sockaddr_storage addr;
1273 int newsock;
1274 socklen_t addrlen;
1275 char buf[16384], *remote_ipaddr;
1276 int remote_port;
1277
1278 if (FD_ISSET(c->sock, readset)) {
1279 debug("X11 connection requested.");
1280 addrlen = sizeof(addr);
1281 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1282 if (c->single_connection) {
1283 debug2("single_connection: closing X11 listener.");
1284 channel_close_fd(&c->sock);
1285 chan_mark_dead(c);
1286 }
1287 if (newsock < 0) {
1288 error("accept: %.100s", strerror(errno));
1289 return;
1290 }
1291 set_nodelay(newsock);
1292 remote_ipaddr = get_peer_ipaddr(newsock);
1293 remote_port = get_peer_port(newsock);
1294 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1295 remote_ipaddr, remote_port);
1296
1297 nc = channel_new("accepted x11 socket",
1298 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1299 c->local_window_max, c->local_maxpacket, 0, buf, 1);
1300 if (compat20) {
1301 packet_start(SSH2_MSG_CHANNEL_OPEN);
1302 packet_put_cstring("x11");
1303 packet_put_int(nc->self);
1304 packet_put_int(nc->local_window_max);
1305 packet_put_int(nc->local_maxpacket);
1306 /* originator ipaddr and port */
1307 packet_put_cstring(remote_ipaddr);
1308 if (datafellows & SSH_BUG_X11FWD) {
1309 debug2("ssh2 x11 bug compat mode");
1310 } else {
1311 packet_put_int(remote_port);
1312 }
1313 packet_send();
1314 } else {
1315 packet_start(SSH_SMSG_X11_OPEN);
1316 packet_put_int(nc->self);
1317 if (packet_get_protocol_flags() &
1318 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1319 packet_put_cstring(buf);
1320 packet_send();
1321 }
1322 xfree(remote_ipaddr);
1323 }
1324 }
1325
1326 static void
1327 port_open_helper(Channel *c, char *rtype)
1328 {
1329 int direct;
1330 char buf[1024];
1331 char *remote_ipaddr = get_peer_ipaddr(c->sock);
1332 int remote_port = get_peer_port(c->sock);
1333
1334 direct = (strcmp(rtype, "direct-tcpip") == 0);
1335
1336 snprintf(buf, sizeof buf,
1337 "%s: listening port %d for %.100s port %d, "
1338 "connect from %.200s port %d",
1339 rtype, c->listening_port, c->path, c->host_port,
1340 remote_ipaddr, remote_port);
1341
1342 xfree(c->remote_name);
1343 c->remote_name = xstrdup(buf);
1344
1345 if (compat20) {
1346 packet_start(SSH2_MSG_CHANNEL_OPEN);
1347 packet_put_cstring(rtype);
1348 packet_put_int(c->self);
1349 packet_put_int(c->local_window_max);
1350 packet_put_int(c->local_maxpacket);
1351 if (direct) {
1352 /* target host, port */
1353 packet_put_cstring(c->path);
1354 packet_put_int(c->host_port);
1355 } else {
1356 /* listen address, port */
1357 packet_put_cstring(c->path);
1358 packet_put_int(c->listening_port);
1359 }
1360 /* originator host and port */
1361 packet_put_cstring(remote_ipaddr);
1362 packet_put_int((u_int)remote_port);
1363 packet_send();
1364 } else {
1365 packet_start(SSH_MSG_PORT_OPEN);
1366 packet_put_int(c->self);
1367 packet_put_cstring(c->path);
1368 packet_put_int(c->host_port);
1369 if (packet_get_protocol_flags() &
1370 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1371 packet_put_cstring(c->remote_name);
1372 packet_send();
1373 }
1374 xfree(remote_ipaddr);
1375 }
1376
1377 static void
1378 channel_set_reuseaddr(int fd)
1379 {
1380 int on = 1;
1381
1382 /*
1383 * Set socket options.
1384 * Allow local port reuse in TIME_WAIT.
1385 */
1386 if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1)
1387 error("setsockopt SO_REUSEADDR fd %d: %s", fd, strerror(errno));
1388 }
1389
1390 /*
1391 * This socket is listening for connections to a forwarded TCP/IP port.
1392 */
1393 /* ARGSUSED */
1394 static void
1395 channel_post_port_listener(Channel *c, fd_set *readset, fd_set *writeset)
1396 {
1397 Channel *nc;
1398 struct sockaddr_storage addr;
1399 int newsock, nextstate;
1400 socklen_t addrlen;
1401 char *rtype;
1402
1403 if (FD_ISSET(c->sock, readset)) {
1404 debug("Connection to port %d forwarding "
1405 "to %.100s port %d requested.",
1406 c->listening_port, c->path, c->host_port);
1407
1408 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1409 nextstate = SSH_CHANNEL_OPENING;
1410 rtype = "forwarded-tcpip";
1411 } else {
1412 if (c->host_port == 0) {
1413 nextstate = SSH_CHANNEL_DYNAMIC;
1414 rtype = "dynamic-tcpip";
1415 } else {
1416 nextstate = SSH_CHANNEL_OPENING;
1417 rtype = "direct-tcpip";
1418 }
1419 }
1420
1421 addrlen = sizeof(addr);
1422 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1423 if (newsock < 0) {
1424 error("accept: %.100s", strerror(errno));
1425 return;
1426 }
1427 set_nodelay(newsock);
1428 nc = channel_new(rtype, nextstate, newsock, newsock, -1,
1429 c->local_window_max, c->local_maxpacket, 0, rtype, 1);
1430 nc->listening_port = c->listening_port;
1431 nc->host_port = c->host_port;
1432 if (c->path != NULL)
1433 nc->path = xstrdup(c->path);
1434
1435 if (nextstate == SSH_CHANNEL_DYNAMIC) {
1436 /*
1437 * do not call the channel_post handler until
1438 * this flag has been reset by a pre-handler.
1439 * otherwise the FD_ISSET calls might overflow
1440 */
1441 nc->delayed = 1;
1442 } else {
1443 port_open_helper(nc, rtype);
1444 }
1445 }
1446 }
1447
1448 /*
1449 * This is the authentication agent socket listening for connections from
1450 * clients.
1451 */
1452 /* ARGSUSED */
1453 static void
1454 channel_post_auth_listener(Channel *c, fd_set *readset, fd_set *writeset)
1455 {
1456 Channel *nc;
1457 int newsock;
1458 struct sockaddr_storage addr;
1459 socklen_t addrlen;
1460
1461 if (FD_ISSET(c->sock, readset)) {
1462 addrlen = sizeof(addr);
1463 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1464 if (newsock < 0) {
1465 error("accept from auth socket: %.100s", strerror(errno));
1466 return;
1467 }
1468 nc = channel_new("accepted auth socket",
1469 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1470 c->local_window_max, c->local_maxpacket,
1471 0, "accepted auth socket", 1);
1472 if (compat20) {
1473 packet_start(SSH2_MSG_CHANNEL_OPEN);
1474 packet_put_cstring("auth-agent@openssh.com");
1475 packet_put_int(nc->self);
1476 packet_put_int(c->local_window_max);
1477 packet_put_int(c->local_maxpacket);
1478 } else {
1479 packet_start(SSH_SMSG_AGENT_OPEN);
1480 packet_put_int(nc->self);
1481 }
1482 packet_send();
1483 }
1484 }
1485
1486 /* ARGSUSED */
1487 static void
1488 channel_post_connecting(Channel *c, fd_set *readset, fd_set *writeset)
1489 {
1490 int err = 0, sock;
1491 socklen_t sz = sizeof(err);
1492
1493 if (FD_ISSET(c->sock, writeset)) {
1494 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) {
1495 err = errno;
1496 error("getsockopt SO_ERROR failed");
1497 }
1498 if (err == 0) {
1499 debug("channel %d: connected to %s port %d",
1500 c->self, c->connect_ctx.host, c->connect_ctx.port);
1501 channel_connect_ctx_free(&c->connect_ctx);
1502 c->type = SSH_CHANNEL_OPEN;
1503 if (compat20) {
1504 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1505 packet_put_int(c->remote_id);
1506 packet_put_int(c->self);
1507 packet_put_int(c->local_window);
1508 packet_put_int(c->local_maxpacket);
1509 } else {
1510 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1511 packet_put_int(c->remote_id);
1512 packet_put_int(c->self);
1513 }
1514 } else {
1515 debug("channel %d: connection failed: %s",
1516 c->self, strerror(err));
1517 /* Try next address, if any */
1518 if ((sock = connect_next(&c->connect_ctx)) > 0) {
1519 close(c->sock);
1520 c->sock = c->rfd = c->wfd = sock;
1521 channel_max_fd = channel_find_maxfd();
1522 return;
1523 }
1524 /* Exhausted all addresses */
1525 error("connect_to %.100s port %d: failed.",
1526 c->connect_ctx.host, c->connect_ctx.port);
1527 channel_connect_ctx_free(&c->connect_ctx);
1528 if (compat20) {
1529 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1530 packet_put_int(c->remote_id);
1531 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1532 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1533 packet_put_cstring(strerror(err));
1534 packet_put_cstring("");
1535 }
1536 } else {
1537 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1538 packet_put_int(c->remote_id);
1539 }
1540 chan_mark_dead(c);
1541 }
1542 packet_send();
1543 }
1544 }
1545
1546 /* ARGSUSED */
1547 static int
1548 channel_handle_rfd(Channel *c, fd_set *readset, fd_set *writeset)
1549 {
1550 char buf[CHAN_RBUF];
1551 int len, force;
1552
1553 force = c->isatty && c->detach_close && c->istate != CHAN_INPUT_CLOSED;
1554 if (c->rfd != -1 && (force || FD_ISSET(c->rfd, readset))) {
1555 errno = 0;
1556 len = read(c->rfd, buf, sizeof(buf));
1557 if (len < 0 && (errno == EINTR ||
1558 ((errno == EAGAIN || errno == EWOULDBLOCK) && !force)))
1559 return 1;
1560 #ifndef PTY_ZEROREAD
1561 if (len <= 0) {
1562 #else
1563 if ((!c->isatty && len <= 0) ||
1564 (c->isatty && (len < 0 || (len == 0 && errno != 0)))) {
1565 #endif
1566 debug2("channel %d: read<=0 rfd %d len %d",
1567 c->self, c->rfd, len);
1568 if (c->type != SSH_CHANNEL_OPEN) {
1569 debug2("channel %d: not open", c->self);
1570 chan_mark_dead(c);
1571 return -1;
1572 } else if (compat13) {
1573 buffer_clear(&c->output);
1574 c->type = SSH_CHANNEL_INPUT_DRAINING;
1575 debug2("channel %d: input draining.", c->self);
1576 } else {
1577 chan_read_failed(c);
1578 }
1579 return -1;
1580 }
1581 if (c->input_filter != NULL) {
1582 if (c->input_filter(c, buf, len) == -1) {
1583 debug2("channel %d: filter stops", c->self);
1584 chan_read_failed(c);
1585 }
1586 } else if (c->datagram) {
1587 buffer_put_string(&c->input, buf, len);
1588 } else {
1589 buffer_append(&c->input, buf, len);
1590 }
1591 }
1592 return 1;
1593 }
1594
1595 /* ARGSUSED */
1596 static int
1597 channel_handle_wfd(Channel *c, fd_set *readset, fd_set *writeset)
1598 {
1599 struct termios tio;
1600 u_char *data = NULL, *buf;
1601 u_int dlen;
1602 int len;
1603
1604 /* Send buffered output data to the socket. */
1605 if (c->wfd != -1 &&
1606 FD_ISSET(c->wfd, writeset) &&
1607 buffer_len(&c->output) > 0) {
1608 if (c->output_filter != NULL) {
1609 if ((buf = c->output_filter(c, &data, &dlen)) == NULL) {
1610 debug2("channel %d: filter stops", c->self);
1611 if (c->type != SSH_CHANNEL_OPEN)
1612 chan_mark_dead(c);
1613 else
1614 chan_write_failed(c);
1615 return -1;
1616 }
1617 } else if (c->datagram) {
1618 buf = data = buffer_get_string(&c->output, &dlen);
1619 } else {
1620 buf = data = buffer_ptr(&c->output);
1621 dlen = buffer_len(&c->output);
1622 }
1623
1624 if (c->datagram) {
1625 /* ignore truncated writes, datagrams might get lost */
1626 c->local_consumed += dlen + 4;
1627 len = write(c->wfd, buf, dlen);
1628 xfree(data);
1629 if (len < 0 && (errno == EINTR || errno == EAGAIN ||
1630 errno == EWOULDBLOCK))
1631 return 1;
1632 if (len <= 0) {
1633 if (c->type != SSH_CHANNEL_OPEN)
1634 chan_mark_dead(c);
1635 else
1636 chan_write_failed(c);
1637 return -1;
1638 }
1639 return 1;
1640 }
1641 #ifdef _AIX
1642 /* XXX: Later AIX versions can't push as much data to tty */
1643 if (compat20 && c->wfd_isatty)
1644 dlen = MIN(dlen, 8*1024);
1645 #endif
1646
1647 len = write(c->wfd, buf, dlen);
1648 if (len < 0 &&
1649 (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK))
1650 return 1;
1651 if (len <= 0) {
1652 if (c->type != SSH_CHANNEL_OPEN) {
1653 debug2("channel %d: not open", c->self);
1654 chan_mark_dead(c);
1655 return -1;
1656 } else if (compat13) {
1657 buffer_clear(&c->output);
1658 debug2("channel %d: input draining.", c->self);
1659 c->type = SSH_CHANNEL_INPUT_DRAINING;
1660 } else {
1661 chan_write_failed(c);
1662 }
1663 return -1;
1664 }
1665 #ifndef BROKEN_TCGETATTR_ICANON
1666 if (compat20 && c->isatty && dlen >= 1 && buf[0] != '\r') {
1667 if (tcgetattr(c->wfd, &tio) == 0 &&
1668 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1669 /*
1670 * Simulate echo to reduce the impact of
1671 * traffic analysis. We need to match the
1672 * size of a SSH2_MSG_CHANNEL_DATA message
1673 * (4 byte channel id + buf)
1674 */
1675 packet_send_ignore(4 + len);
1676 packet_send();
1677 }
1678 }
1679 #endif
1680 buffer_consume(&c->output, len);
1681 if (compat20 && len > 0) {
1682 c->local_consumed += len;
1683 }
1684 }
1685 return 1;
1686 }
1687
1688 static int
1689 channel_handle_efd(Channel *c, fd_set *readset, fd_set *writeset)
1690 {
1691 char buf[CHAN_RBUF];
1692 int len;
1693
1694 /** XXX handle drain efd, too */
1695 if (c->efd != -1) {
1696 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1697 FD_ISSET(c->efd, writeset) &&
1698 buffer_len(&c->extended) > 0) {
1699 len = write(c->efd, buffer_ptr(&c->extended),
1700 buffer_len(&c->extended));
1701 debug2("channel %d: written %d to efd %d",
1702 c->self, len, c->efd);
1703 if (len < 0 && (errno == EINTR || errno == EAGAIN ||
1704 errno == EWOULDBLOCK))
1705 return 1;
1706 if (len <= 0) {
1707 debug2("channel %d: closing write-efd %d",
1708 c->self, c->efd);
1709 channel_close_fd(&c->efd);
1710 } else {
1711 buffer_consume(&c->extended, len);
1712 c->local_consumed += len;
1713 }
1714 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
1715 (c->detach_close || FD_ISSET(c->efd, readset))) {
1716 len = read(c->efd, buf, sizeof(buf));
1717 debug2("channel %d: read %d from efd %d",
1718 c->self, len, c->efd);
1719 if (len < 0 && (errno == EINTR || ((errno == EAGAIN ||
1720 errno == EWOULDBLOCK) && !c->detach_close)))
1721 return 1;
1722 if (len <= 0) {
1723 debug2("channel %d: closing read-efd %d",
1724 c->self, c->efd);
1725 channel_close_fd(&c->efd);
1726 } else {
1727 buffer_append(&c->extended, buf, len);
1728 }
1729 }
1730 }
1731 return 1;
1732 }
1733
1734 /* ARGSUSED */
1735 static int
1736 channel_handle_ctl(Channel *c, fd_set *readset, fd_set *writeset)
1737 {
1738 char buf[16];
1739 int len;
1740
1741 /* Monitor control fd to detect if the slave client exits */
1742 if (c->ctl_fd != -1 && FD_ISSET(c->ctl_fd, readset)) {
1743 len = read(c->ctl_fd, buf, sizeof(buf));
1744 if (len < 0 &&
1745 (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK))
1746 return 1;
1747 if (len <= 0) {
1748 debug2("channel %d: ctl read<=0", c->self);
1749 if (c->type != SSH_CHANNEL_OPEN) {
1750 debug2("channel %d: not open", c->self);
1751 chan_mark_dead(c);
1752 return -1;
1753 } else {
1754 chan_read_failed(c);
1755 chan_write_failed(c);
1756 }
1757 return -1;
1758 } else
1759 fatal("%s: unexpected data on ctl fd", __func__);
1760 }
1761 return 1;
1762 }
1763
1764 static int
1765 channel_check_window(Channel *c)
1766 {
1767 if (c->type == SSH_CHANNEL_OPEN &&
1768 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1769 ((c->local_window_max - c->local_window >
1770 c->local_maxpacket*3) ||
1771 c->local_window < c->local_window_max/2) &&
1772 c->local_consumed > 0) {
1773 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1774 packet_put_int(c->remote_id);
1775 packet_put_int(c->local_consumed);
1776 packet_send();
1777 debug2("channel %d: window %d sent adjust %d",
1778 c->self, c->local_window,
1779 c->local_consumed);
1780 c->local_window += c->local_consumed;
1781 c->local_consumed = 0;
1782 }
1783 return 1;
1784 }
1785
1786 static void
1787 channel_post_open(Channel *c, fd_set *readset, fd_set *writeset)
1788 {
1789 if (c->delayed)
1790 return;
1791 channel_handle_rfd(c, readset, writeset);
1792 channel_handle_wfd(c, readset, writeset);
1793 if (!compat20)
1794 return;
1795 channel_handle_efd(c, readset, writeset);
1796 channel_handle_ctl(c, readset, writeset);
1797 channel_check_window(c);
1798 }
1799
1800 /* ARGSUSED */
1801 static void
1802 channel_post_output_drain_13(Channel *c, fd_set *readset, fd_set *writeset)
1803 {
1804 int len;
1805
1806 /* Send buffered output data to the socket. */
1807 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1808 len = write(c->sock, buffer_ptr(&c->output),
1809 buffer_len(&c->output));
1810 if (len <= 0)
1811 buffer_clear(&c->output);
1812 else
1813 buffer_consume(&c->output, len);
1814 }
1815 }
1816
1817 static void
1818 channel_handler_init_20(void)
1819 {
1820 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1821 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1822 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1823 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
1824 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1825 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1826 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1827 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1828
1829 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1830 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1831 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
1832 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1833 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1834 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1835 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1836 }
1837
1838 static void
1839 channel_handler_init_13(void)
1840 {
1841 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
1842 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
1843 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1844 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1845 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1846 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
1847 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1848 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1849 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1850
1851 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1852 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1853 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1854 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1855 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
1856 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1857 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1858 }
1859
1860 static void
1861 channel_handler_init_15(void)
1862 {
1863 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1864 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1865 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1866 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1867 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1868 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1869 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1870
1871 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1872 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1873 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1874 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1875 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1876 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1877 }
1878
1879 static void
1880 channel_handler_init(void)
1881 {
1882 int i;
1883
1884 for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
1885 channel_pre[i] = NULL;
1886 channel_post[i] = NULL;
1887 }
1888 if (compat20)
1889 channel_handler_init_20();
1890 else if (compat13)
1891 channel_handler_init_13();
1892 else
1893 channel_handler_init_15();
1894 }
1895
1896 /* gc dead channels */
1897 static void
1898 channel_garbage_collect(Channel *c)
1899 {
1900 if (c == NULL)
1901 return;
1902 if (c->detach_user != NULL) {
1903 if (!chan_is_dead(c, c->detach_close))
1904 return;
1905 debug2("channel %d: gc: notify user", c->self);
1906 c->detach_user(c->self, NULL);
1907 /* if we still have a callback */
1908 if (c->detach_user != NULL)
1909 return;
1910 debug2("channel %d: gc: user detached", c->self);
1911 }
1912 if (!chan_is_dead(c, 1))
1913 return;
1914 debug2("channel %d: garbage collecting", c->self);
1915 channel_free(c);
1916 }
1917
1918 static void
1919 channel_handler(chan_fn *ftab[], fd_set *readset, fd_set *writeset)
1920 {
1921 static int did_init = 0;
1922 u_int i;
1923 Channel *c;
1924
1925 if (!did_init) {
1926 channel_handler_init();
1927 did_init = 1;
1928 }
1929 for (i = 0; i < channels_alloc; i++) {
1930 c = channels[i];
1931 if (c == NULL)
1932 continue;
1933 if (ftab[c->type] != NULL)
1934 (*ftab[c->type])(c, readset, writeset);
1935 channel_garbage_collect(c);
1936 }
1937 }
1938
1939 /*
1940 * Allocate/update select bitmasks and add any bits relevant to channels in
1941 * select bitmasks.
1942 */
1943 void
1944 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
1945 u_int *nallocp, int rekeying)
1946 {
1947 u_int n, sz, nfdset;
1948
1949 n = MAX(*maxfdp, channel_max_fd);
1950
1951 nfdset = howmany(n+1, NFDBITS);
1952 /* Explicitly test here, because xrealloc isn't always called */
1953 if (nfdset && SIZE_T_MAX / nfdset < sizeof(fd_mask))
1954 fatal("channel_prepare_select: max_fd (%d) is too large", n);
1955 sz = nfdset * sizeof(fd_mask);
1956
1957 /* perhaps check sz < nalloc/2 and shrink? */
1958 if (*readsetp == NULL || sz > *nallocp) {
1959 *readsetp = xrealloc(*readsetp, nfdset, sizeof(fd_mask));
1960 *writesetp = xrealloc(*writesetp, nfdset, sizeof(fd_mask));
1961 *nallocp = sz;
1962 }
1963 *maxfdp = n;
1964 memset(*readsetp, 0, sz);
1965 memset(*writesetp, 0, sz);
1966
1967 if (!rekeying)
1968 channel_handler(channel_pre, *readsetp, *writesetp);
1969 }
1970
1971 /*
1972 * After select, perform any appropriate operations for channels which have
1973 * events pending.
1974 */
1975 void
1976 channel_after_select(fd_set *readset, fd_set *writeset)
1977 {
1978 channel_handler(channel_post, readset, writeset);
1979 }
1980
1981
1982 /* If there is data to send to the connection, enqueue some of it now. */
1983 void
1984 channel_output_poll(void)
1985 {
1986 Channel *c;
1987 u_int i, len;
1988
1989 for (i = 0; i < channels_alloc; i++) {
1990 c = channels[i];
1991 if (c == NULL)
1992 continue;
1993
1994 /*
1995 * We are only interested in channels that can have buffered
1996 * incoming data.
1997 */
1998 if (compat13) {
1999 if (c->type != SSH_CHANNEL_OPEN &&
2000 c->type != SSH_CHANNEL_INPUT_DRAINING)
2001 continue;
2002 } else {
2003 if (c->type != SSH_CHANNEL_OPEN)
2004 continue;
2005 }
2006 if (compat20 &&
2007 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
2008 /* XXX is this true? */
2009 debug3("channel %d: will not send data after close", c->self);
2010 continue;
2011 }
2012
2013 /* Get the amount of buffered data for this channel. */
2014 if ((c->istate == CHAN_INPUT_OPEN ||
2015 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
2016 (len = buffer_len(&c->input)) > 0) {
2017 if (c->datagram) {
2018 if (len > 0) {
2019 u_char *data;
2020 u_int dlen;
2021
2022 data = buffer_get_string(&c->input,
2023 &dlen);
2024 packet_start(SSH2_MSG_CHANNEL_DATA);
2025 packet_put_int(c->remote_id);
2026 packet_put_string(data, dlen);
2027 packet_send();
2028 c->remote_window -= dlen + 4;
2029 xfree(data);
2030 }
2031 continue;
2032 }
2033 /*
2034 * Send some data for the other side over the secure
2035 * connection.
2036 */
2037 if (compat20) {
2038 if (len > c->remote_window)
2039 len = c->remote_window;
2040 if (len > c->remote_maxpacket)
2041 len = c->remote_maxpacket;
2042 } else {
2043 if (packet_is_interactive()) {
2044 if (len > 1024)
2045 len = 512;
2046 } else {
2047 /* Keep the packets at reasonable size. */
2048 if (len > packet_get_maxsize()/2)
2049 len = packet_get_maxsize()/2;
2050 }
2051 }
2052 if (len > 0) {
2053 packet_start(compat20 ?
2054 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
2055 packet_put_int(c->remote_id);
2056 packet_put_string(buffer_ptr(&c->input), len);
2057 packet_send();
2058 buffer_consume(&c->input, len);
2059 c->remote_window -= len;
2060 }
2061 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
2062 if (compat13)
2063 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
2064 /*
2065 * input-buffer is empty and read-socket shutdown:
2066 * tell peer, that we will not send more data: send IEOF.
2067 * hack for extended data: delay EOF if EFD still in use.
2068 */
2069 if (CHANNEL_EFD_INPUT_ACTIVE(c))
2070 debug2("channel %d: ibuf_empty delayed efd %d/(%d)",
2071 c->self, c->efd, buffer_len(&c->extended));
2072 else
2073 chan_ibuf_empty(c);
2074 }
2075 /* Send extended data, i.e. stderr */
2076 if (compat20 &&
2077 !(c->flags & CHAN_EOF_SENT) &&
2078 c->remote_window > 0 &&
2079 (len = buffer_len(&c->extended)) > 0 &&
2080 c->extended_usage == CHAN_EXTENDED_READ) {
2081 debug2("channel %d: rwin %u elen %u euse %d",
2082 c->self, c->remote_window, buffer_len(&c->extended),
2083 c->extended_usage);
2084 if (len > c->remote_window)
2085 len = c->remote_window;
2086 if (len > c->remote_maxpacket)
2087 len = c->remote_maxpacket;
2088 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
2089 packet_put_int(c->remote_id);
2090 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
2091 packet_put_string(buffer_ptr(&c->extended), len);
2092 packet_send();
2093 buffer_consume(&c->extended, len);
2094 c->remote_window -= len;
2095 debug2("channel %d: sent ext data %d", c->self, len);
2096 }
2097 }
2098 }
2099
2100
2101 /* -- protocol input */
2102
2103 /* ARGSUSED */
2104 void
2105 channel_input_data(int type, u_int32_t seq, void *ctxt)
2106 {
2107 int id;
2108 char *data;
2109 u_int data_len;
2110 Channel *c;
2111
2112 /* Get the channel number and verify it. */
2113 id = packet_get_int();
2114 c = channel_lookup(id);
2115 if (c == NULL)
2116 packet_disconnect("Received data for nonexistent channel %d.", id);
2117
2118 /* Ignore any data for non-open channels (might happen on close) */
2119 if (c->type != SSH_CHANNEL_OPEN &&
2120 c->type != SSH_CHANNEL_X11_OPEN)
2121 return;
2122
2123 /* Get the data. */
2124 data = packet_get_string_ptr(&data_len);
2125
2126 /*
2127 * Ignore data for protocol > 1.3 if output end is no longer open.
2128 * For protocol 2 the sending side is reducing its window as it sends
2129 * data, so we must 'fake' consumption of the data in order to ensure
2130 * that window updates are sent back. Otherwise the connection might
2131 * deadlock.
2132 */
2133 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) {
2134 if (compat20) {
2135 c->local_window -= data_len;
2136 c->local_consumed += data_len;
2137 }
2138 return;
2139 }
2140
2141 if (compat20) {
2142 if (data_len > c->local_maxpacket) {
2143 logit("channel %d: rcvd big packet %d, maxpack %d",
2144 c->self, data_len, c->local_maxpacket);
2145 }
2146 if (data_len > c->local_window) {
2147 logit("channel %d: rcvd too much data %d, win %d",
2148 c->self, data_len, c->local_window);
2149 return;
2150 }
2151 c->local_window -= data_len;
2152 }
2153 if (c->datagram)
2154 buffer_put_string(&c->output, data, data_len);
2155 else
2156 buffer_append(&c->output, data, data_len);
2157 packet_check_eom();
2158 }
2159
2160 /* ARGSUSED */
2161 void
2162 channel_input_extended_data(int type, u_int32_t seq, void *ctxt)
2163 {
2164 int id;
2165 char *data;
2166 u_int data_len, tcode;
2167 Channel *c;
2168
2169 /* Get the channel number and verify it. */
2170 id = packet_get_int();
2171 c = channel_lookup(id);
2172
2173 if (c == NULL)
2174 packet_disconnect("Received extended_data for bad channel %d.", id);
2175 if (c->type != SSH_CHANNEL_OPEN) {
2176 logit("channel %d: ext data for non open", id);
2177 return;
2178 }
2179 if (c->flags & CHAN_EOF_RCVD) {
2180 if (datafellows & SSH_BUG_EXTEOF)
2181 debug("channel %d: accepting ext data after eof", id);
2182 else
2183 packet_disconnect("Received extended_data after EOF "
2184 "on channel %d.", id);
2185 }
2186 tcode = packet_get_int();
2187 if (c->efd == -1 ||
2188 c->extended_usage != CHAN_EXTENDED_WRITE ||
2189 tcode != SSH2_EXTENDED_DATA_STDERR) {
2190 logit("channel %d: bad ext data", c->self);
2191 return;
2192 }
2193 data = packet_get_string(&data_len);
2194 packet_check_eom();
2195 if (data_len > c->local_window) {
2196 logit("channel %d: rcvd too much extended_data %d, win %d",
2197 c->self, data_len, c->local_window);
2198 xfree(data);
2199 return;
2200 }
2201 debug2("channel %d: rcvd ext data %d", c->self, data_len);
2202 c->local_window -= data_len;
2203 buffer_append(&c->extended, data, data_len);
2204 xfree(data);
2205 }
2206
2207 /* ARGSUSED */
2208 void
2209 channel_input_ieof(int type, u_int32_t seq, void *ctxt)
2210 {
2211 int id;
2212 Channel *c;
2213
2214 id = packet_get_int();
2215 packet_check_eom();
2216 c = channel_lookup(id);
2217 if (c == NULL)
2218 packet_disconnect("Received ieof for nonexistent channel %d.", id);
2219 chan_rcvd_ieof(c);
2220
2221 /* XXX force input close */
2222 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) {
2223 debug("channel %d: FORCE input drain", c->self);
2224 c->istate = CHAN_INPUT_WAIT_DRAIN;
2225 if (buffer_len(&c->input) == 0)
2226 chan_ibuf_empty(c);
2227 }
2228
2229 }
2230
2231 /* ARGSUSED */
2232 void
2233 channel_input_close(int type, u_int32_t seq, void *ctxt)
2234 {
2235 int id;
2236 Channel *c;
2237
2238 id = packet_get_int();
2239 packet_check_eom();
2240 c = channel_lookup(id);
2241 if (c == NULL)
2242 packet_disconnect("Received close for nonexistent channel %d.", id);
2243
2244 /*
2245 * Send a confirmation that we have closed the channel and no more
2246 * data is coming for it.
2247 */
2248 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
2249 packet_put_int(c->remote_id);
2250 packet_send();
2251
2252 /*
2253 * If the channel is in closed state, we have sent a close request,
2254 * and the other side will eventually respond with a confirmation.
2255 * Thus, we cannot free the channel here, because then there would be
2256 * no-one to receive the confirmation. The channel gets freed when
2257 * the confirmation arrives.
2258 */
2259 if (c->type != SSH_CHANNEL_CLOSED) {
2260 /*
2261 * Not a closed channel - mark it as draining, which will
2262 * cause it to be freed later.
2263 */
2264 buffer_clear(&c->input);
2265 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
2266 }
2267 }
2268
2269 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
2270 /* ARGSUSED */
2271 void
2272 channel_input_oclose(int type, u_int32_t seq, void *ctxt)
2273 {
2274 int id = packet_get_int();
2275 Channel *c = channel_lookup(id);
2276
2277 packet_check_eom();
2278 if (c == NULL)
2279 packet_disconnect("Received oclose for nonexistent channel %d.", id);
2280 chan_rcvd_oclose(c);
2281 }
2282
2283 /* ARGSUSED */
2284 void
2285 channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt)
2286 {
2287 int id = packet_get_int();
2288 Channel *c = channel_lookup(id);
2289
2290 packet_check_eom();
2291 if (c == NULL)
2292 packet_disconnect("Received close confirmation for "
2293 "out-of-range channel %d.", id);
2294 if (c->type != SSH_CHANNEL_CLOSED)
2295 packet_disconnect("Received close confirmation for "
2296 "non-closed channel %d (type %d).", id, c->type);
2297 channel_free(c);
2298 }
2299
2300 /* ARGSUSED */
2301 void
2302 channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt)
2303 {
2304 int id, remote_id;
2305 Channel *c;
2306
2307 id = packet_get_int();
2308 c = channel_lookup(id);
2309
2310 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2311 packet_disconnect("Received open confirmation for "
2312 "non-opening channel %d.", id);
2313 remote_id = packet_get_int();
2314 /* Record the remote channel number and mark that the channel is now open. */
2315 c->remote_id = remote_id;
2316 c->type = SSH_CHANNEL_OPEN;
2317
2318 if (compat20) {
2319 c->remote_window = packet_get_int();
2320 c->remote_maxpacket = packet_get_int();
2321 if (c->open_confirm) {
2322 debug2("callback start");
2323 c->open_confirm(c->self, c->open_confirm_ctx);
2324 debug2("callback done");
2325 }
2326 debug2("channel %d: open confirm rwindow %u rmax %u", c->self,
2327 c->remote_window, c->remote_maxpacket);
2328 }
2329 packet_check_eom();
2330 }
2331
2332 static char *
2333 reason2txt(int reason)
2334 {
2335 switch (reason) {
2336 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
2337 return "administratively prohibited";
2338 case SSH2_OPEN_CONNECT_FAILED:
2339 return "connect failed";
2340 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
2341 return "unknown channel type";
2342 case SSH2_OPEN_RESOURCE_SHORTAGE:
2343 return "resource shortage";
2344 }
2345 return "unknown reason";
2346 }
2347
2348 /* ARGSUSED */
2349 void
2350 channel_input_open_failure(int type, u_int32_t seq, void *ctxt)
2351 {
2352 int id, reason;
2353 char *msg = NULL, *lang = NULL;
2354 Channel *c;
2355
2356 id = packet_get_int();
2357 c = channel_lookup(id);
2358
2359 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2360 packet_disconnect("Received open failure for "
2361 "non-opening channel %d.", id);
2362 if (compat20) {
2363 reason = packet_get_int();
2364 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
2365 msg = packet_get_string(NULL);
2366 lang = packet_get_string(NULL);
2367 }
2368 logit("channel %d: open failed: %s%s%s", id,
2369 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
2370 if (msg != NULL)
2371 xfree(msg);
2372 if (lang != NULL)
2373 xfree(lang);
2374 }
2375 packet_check_eom();
2376 /* Schedule the channel for cleanup/deletion. */
2377 chan_mark_dead(c);
2378 }
2379
2380 /* ARGSUSED */
2381 void
2382 channel_input_window_adjust(int type, u_int32_t seq, void *ctxt)
2383 {
2384 Channel *c;
2385 int id;
2386 u_int adjust;
2387
2388 if (!compat20)
2389 return;
2390
2391 /* Get the channel number and verify it. */
2392 id = packet_get_int();
2393 c = channel_lookup(id);
2394
2395 if (c == NULL) {
2396 logit("Received window adjust for non-open channel %d.", id);
2397 return;
2398 }
2399 adjust = packet_get_int();
2400 packet_check_eom();
2401 debug2("channel %d: rcvd adjust %u", id, adjust);
2402 c->remote_window += adjust;
2403 }
2404
2405 /* ARGSUSED */
2406 void
2407 channel_input_port_open(int type, u_int32_t seq, void *ctxt)
2408 {
2409 Channel *c = NULL;
2410 u_short host_port;
2411 char *host, *originator_string;
2412 int remote_id;
2413
2414 remote_id = packet_get_int();
2415 host = packet_get_string(NULL);
2416 host_port = packet_get_int();
2417
2418 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2419 originator_string = packet_get_string(NULL);
2420 } else {
2421 originator_string = xstrdup("unknown (remote did not supply name)");
2422 }
2423 packet_check_eom();
2424 c = channel_connect_to(host, host_port,
2425 "connected socket", originator_string);
2426 xfree(originator_string);
2427 xfree(host);
2428 if (c == NULL) {
2429 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2430 packet_put_int(remote_id);
2431 packet_send();
2432 } else
2433 c->remote_id = remote_id;
2434 }
2435
2436 /* ARGSUSED */
2437 void
2438 channel_input_status_confirm(int type, u_int32_t seq, void *ctxt)
2439 {
2440 Channel *c;
2441 struct channel_confirm *cc;
2442 int id;
2443
2444 /* Reset keepalive timeout */
2445 packet_set_alive_timeouts(0);
2446
2447 id = packet_get_int();
2448 packet_check_eom();
2449
2450 debug2("channel_input_status_confirm: type %d id %d", type, id);
2451
2452 if ((c = channel_lookup(id)) == NULL) {
2453 logit("channel_input_status_confirm: %d: unknown", id);
2454 return;
2455 }
2456 ;
2457 if ((cc = TAILQ_FIRST(&c->status_confirms)) == NULL)
2458 return;
2459 cc->cb(type, c, cc->ctx);
2460 TAILQ_REMOVE(&c->status_confirms, cc, entry);
2461 bzero(cc, sizeof(*cc));
2462 xfree(cc);
2463 }
2464
2465 /* -- tcp forwarding */
2466
2467 void
2468 channel_set_af(int af)
2469 {
2470 IPv4or6 = af;
2471 }
2472
2473 void
2474 channel_set_rdomain(int rdomain)
2475 {
2476 channel_rdomain = rdomain;
2477 }
2478
2479 static int
2480 channel_setup_fwd_listener(int type, const char *listen_addr,
2481 u_short listen_port, int *allocated_listen_port,
2482 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2483 {
2484 Channel *c;
2485 int sock, r, success = 0, wildcard = 0, is_client;
2486 struct addrinfo hints, *ai, *aitop;
2487 const char *host, *addr;
2488 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2489 in_port_t *lport_p;
2490
2491 host = (type == SSH_CHANNEL_RPORT_LISTENER) ?
2492 listen_addr : host_to_connect;
2493 is_client = (type == SSH_CHANNEL_PORT_LISTENER);
2494
2495 if (host == NULL) {
2496 error("No forward host name.");
2497 return 0;
2498 }
2499 if (strlen(host) >= NI_MAXHOST) {
2500 error("Forward host name too long.");
2501 return 0;
2502 }
2503
2504 /*
2505 * Determine whether or not a port forward listens to loopback,
2506 * specified address or wildcard. On the client, a specified bind
2507 * address will always override gateway_ports. On the server, a
2508 * gateway_ports of 1 (``yes'') will override the client's
2509 * specification and force a wildcard bind, whereas a value of 2
2510 * (``clientspecified'') will bind to whatever address the client
2511 * asked for.
2512 *
2513 * Special-case listen_addrs are:
2514 *
2515 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR
2516 * "" (empty string), "*" -> wildcard v4/v6
2517 * "localhost" -> loopback v4/v6
2518 */
2519 addr = NULL;
2520 if (listen_addr == NULL) {
2521 /* No address specified: default to gateway_ports setting */
2522 if (gateway_ports)
2523 wildcard = 1;
2524 } else if (gateway_ports || is_client) {
2525 if (((datafellows & SSH_OLD_FORWARD_ADDR) &&
2526 strcmp(listen_addr, "0.0.0.0") == 0 && is_client == 0) ||
2527 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 ||
2528 (!is_client && gateway_ports == 1))
2529 wildcard = 1;
2530 else if (strcmp(listen_addr, "localhost") != 0)
2531 addr = listen_addr;
2532 }
2533
2534 debug3("channel_setup_fwd_listener: type %d wildcard %d addr %s",
2535 type, wildcard, (addr == NULL) ? "NULL" : addr);
2536
2537 /*
2538 * getaddrinfo returns a loopback address if the hostname is
2539 * set to NULL and hints.ai_flags is not AI_PASSIVE
2540 */
2541 memset(&hints, 0, sizeof(hints));
2542 hints.ai_family = IPv4or6;
2543 hints.ai_flags = wildcard ? AI_PASSIVE : 0;
2544 hints.ai_socktype = SOCK_STREAM;
2545 snprintf(strport, sizeof strport, "%d", listen_port);
2546 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) {
2547 if (addr == NULL) {
2548 /* This really shouldn't happen */
2549 packet_disconnect("getaddrinfo: fatal error: %s",
2550 ssh_gai_strerror(r));
2551 } else {
2552 error("channel_setup_fwd_listener: "
2553 "getaddrinfo(%.64s): %s", addr,
2554 ssh_gai_strerror(r));
2555 }
2556 return 0;
2557 }
2558 if (allocated_listen_port != NULL)
2559 *allocated_listen_port = 0;
2560 for (ai = aitop; ai; ai = ai->ai_next) {
2561 switch (ai->ai_family) {
2562 case AF_INET:
2563 lport_p = &((struct sockaddr_in *)ai->ai_addr)->
2564 sin_port;
2565 break;
2566 case AF_INET6:
2567 lport_p = &((struct sockaddr_in6 *)ai->ai_addr)->
2568 sin6_port;
2569 break;
2570 default:
2571 continue;
2572 }
2573 /*
2574 * If allocating a port for -R forwards, then use the
2575 * same port for all address families.
2576 */
2577 if (type == SSH_CHANNEL_RPORT_LISTENER && listen_port == 0 &&
2578 allocated_listen_port != NULL && *allocated_listen_port > 0)
2579 *lport_p = htons(*allocated_listen_port);
2580
2581 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2582 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2583 error("channel_setup_fwd_listener: getnameinfo failed");
2584 continue;
2585 }
2586 /* Create a port to listen for the host. */
2587 sock = socket_rdomain(ai->ai_family, ai->ai_socktype,
2588 ai->ai_protocol, channel_rdomain);
2589 if (sock < 0) {
2590 /* this is no error since kernel may not support ipv6 */
2591 verbose("socket: %.100s", strerror(errno));
2592 continue;
2593 }
2594
2595 channel_set_reuseaddr(sock);
2596 if (ai->ai_family == AF_INET6)
2597 sock_set_v6only(sock);
2598
2599 debug("Local forwarding listening on %s port %s.",
2600 ntop, strport);
2601
2602 /* Bind the socket to the address. */
2603 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2604 /* address can be in use ipv6 address is already bound */
2605 if (!ai->ai_next)
2606 error("bind: %.100s", strerror(errno));
2607 else
2608 verbose("bind: %.100s", strerror(errno));
2609
2610 close(sock);
2611 continue;
2612 }
2613 /* Start listening for connections on the socket. */
2614 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2615 error("listen: %.100s", strerror(errno));
2616 close(sock);
2617 continue;
2618 }
2619
2620 /*
2621 * listen_port == 0 requests a dynamically allocated port -
2622 * record what we got.
2623 */
2624 if (type == SSH_CHANNEL_RPORT_LISTENER && listen_port == 0 &&
2625 allocated_listen_port != NULL &&
2626 *allocated_listen_port == 0) {
2627 *allocated_listen_port = get_sock_port(sock, 1);
2628 debug("Allocated listen port %d",
2629 *allocated_listen_port);
2630 }
2631
2632 /* Allocate a channel number for the socket. */
2633 c = channel_new("port listener", type, sock, sock, -1,
2634 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2635 0, "port listener", 1);
2636 c->path = xstrdup(host);
2637 c->host_port = port_to_connect;
2638 c->listening_port = listen_port;
2639 success = 1;
2640 }
2641 if (success == 0)
2642 error("channel_setup_fwd_listener: cannot listen to port: %d",
2643 listen_port);
2644 freeaddrinfo(aitop);
2645 return success;
2646 }
2647
2648 int
2649 channel_cancel_rport_listener(const char *host, u_short port)
2650 {
2651 u_int i;
2652 int found = 0;
2653
2654 for (i = 0; i < channels_alloc; i++) {
2655 Channel *c = channels[i];
2656
2657 if (c != NULL && c->type == SSH_CHANNEL_RPORT_LISTENER &&
2658 strcmp(c->path, host) == 0 && c->listening_port == port) {
2659 debug2("%s: close channel %d", __func__, i);
2660 channel_free(c);
2661 found = 1;
2662 }
2663 }
2664
2665 return (found);
2666 }
2667
2668 /* protocol local port fwd, used by ssh (and sshd in v1) */
2669 int
2670 channel_setup_local_fwd_listener(const char *listen_host, u_short listen_port,
2671 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2672 {
2673 return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER,
2674 listen_host, listen_port, NULL, host_to_connect, port_to_connect,
2675 gateway_ports);
2676 }
2677
2678 /* protocol v2 remote port fwd, used by sshd */
2679 int
2680 channel_setup_remote_fwd_listener(const char *listen_address,
2681 u_short listen_port, int *allocated_listen_port, int gateway_ports)
2682 {
2683 return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER,
2684 listen_address, listen_port, allocated_listen_port,
2685 NULL, 0, gateway_ports);
2686 }
2687
2688 /*
2689 * Initiate forwarding of connections to port "port" on remote host through
2690 * the secure channel to host:port from local side.
2691 */
2692
2693 int
2694 channel_request_remote_forwarding(const char *listen_host, u_short listen_port,
2695 const char *host_to_connect, u_short port_to_connect)
2696 {
2697 int type, success = 0;
2698
2699 /* Record locally that connection to this host/port is permitted. */
2700 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2701 fatal("channel_request_remote_forwarding: too many forwards");
2702
2703 /* Send the forward request to the remote side. */
2704 if (compat20) {
2705 const char *address_to_bind;
2706 if (listen_host == NULL) {
2707 if (datafellows & SSH_BUG_RFWD_ADDR)
2708 address_to_bind = "127.0.0.1";
2709 else
2710 address_to_bind = "localhost";
2711 } else if (*listen_host == '\0' ||
2712 strcmp(listen_host, "*") == 0) {
2713 if (datafellows & SSH_BUG_RFWD_ADDR)
2714 address_to_bind = "0.0.0.0";
2715 else
2716 address_to_bind = "";
2717 } else
2718 address_to_bind = listen_host;
2719
2720 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2721 packet_put_cstring("tcpip-forward");
2722 packet_put_char(1); /* boolean: want reply */
2723 packet_put_cstring(address_to_bind);
2724 packet_put_int(listen_port);
2725 packet_send();
2726 packet_write_wait();
2727 /* Assume that server accepts the request */
2728 success = 1;
2729 } else {
2730 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2731 packet_put_int(listen_port);
2732 packet_put_cstring(host_to_connect);
2733 packet_put_int(port_to_connect);
2734 packet_send();
2735 packet_write_wait();
2736
2737 /* Wait for response from the remote side. */
2738 type = packet_read();
2739 switch (type) {
2740 case SSH_SMSG_SUCCESS:
2741 success = 1;
2742 break;
2743 case SSH_SMSG_FAILURE:
2744 break;
2745 default:
2746 /* Unknown packet */
2747 packet_disconnect("Protocol error for port forward request:"
2748 "received packet type %d.", type);
2749 }
2750 }
2751 if (success) {
2752 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2753 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2754 permitted_opens[num_permitted_opens].listen_port = listen_port;
2755 num_permitted_opens++;
2756 }
2757 return (success ? 0 : -1);
2758 }
2759
2760 /*
2761 * Request cancellation of remote forwarding of connection host:port from
2762 * local side.
2763 */
2764 void
2765 channel_request_rforward_cancel(const char *host, u_short port)
2766 {
2767 int i;
2768
2769 if (!compat20)
2770 return;
2771
2772 for (i = 0; i < num_permitted_opens; i++) {
2773 if (permitted_opens[i].host_to_connect != NULL &&
2774 permitted_opens[i].listen_port == port)
2775 break;
2776 }
2777 if (i >= num_permitted_opens) {
2778 debug("%s: requested forward not found", __func__);
2779 return;
2780 }
2781 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2782 packet_put_cstring("cancel-tcpip-forward");
2783 packet_put_char(0);
2784 packet_put_cstring(host == NULL ? "" : host);
2785 packet_put_int(port);
2786 packet_send();
2787
2788 permitted_opens[i].listen_port = 0;
2789 permitted_opens[i].port_to_connect = 0;
2790 xfree(permitted_opens[i].host_to_connect);
2791 permitted_opens[i].host_to_connect = NULL;
2792 }
2793
2794 /*
2795 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
2796 * listening for the port, and sends back a success reply (or disconnect
2797 * message if there was an error).
2798 */
2799 int
2800 channel_input_port_forward_request(int is_root, int gateway_ports)
2801 {
2802 u_short port, host_port;
2803 int success = 0;
2804 char *hostname;
2805
2806 /* Get arguments from the packet. */
2807 port = packet_get_int();
2808 hostname = packet_get_string(NULL);
2809 host_port = packet_get_int();
2810
2811 #ifndef HAVE_CYGWIN
2812 /*
2813 * Check that an unprivileged user is not trying to forward a
2814 * privileged port.
2815 */
2816 if (port < IPPORT_RESERVED && !is_root)
2817 packet_disconnect(
2818 "Requested forwarding of port %d but user is not root.",
2819 port);
2820 if (host_port == 0)
2821 packet_disconnect("Dynamic forwarding denied.");
2822 #endif
2823
2824 /* Initiate forwarding */
2825 success = channel_setup_local_fwd_listener(NULL, port, hostname,
2826 host_port, gateway_ports);
2827
2828 /* Free the argument string. */
2829 xfree(hostname);
2830
2831 return (success ? 0 : -1);
2832 }
2833
2834 /*
2835 * Permits opening to any host/port if permitted_opens[] is empty. This is
2836 * usually called by the server, because the user could connect to any port
2837 * anyway, and the server has no way to know but to trust the client anyway.
2838 */
2839 void
2840 channel_permit_all_opens(void)
2841 {
2842 if (num_permitted_opens == 0)
2843 all_opens_permitted = 1;
2844 }
2845
2846 void
2847 channel_add_permitted_opens(char *host, int port)
2848 {
2849 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2850 fatal("channel_add_permitted_opens: too many forwards");
2851 debug("allow port forwarding to host %s port %d", host, port);
2852
2853 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
2854 permitted_opens[num_permitted_opens].port_to_connect = port;
2855 num_permitted_opens++;
2856
2857 all_opens_permitted = 0;
2858 }
2859
2860 int
2861 channel_add_adm_permitted_opens(char *host, int port)
2862 {
2863 if (num_adm_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2864 fatal("channel_add_adm_permitted_opens: too many forwards");
2865 debug("config allows port forwarding to host %s port %d", host, port);
2866
2867 permitted_adm_opens[num_adm_permitted_opens].host_to_connect
2868 = xstrdup(host);
2869 permitted_adm_opens[num_adm_permitted_opens].port_to_connect = port;
2870 return ++num_adm_permitted_opens;
2871 }
2872
2873 void
2874 channel_clear_permitted_opens(void)
2875 {
2876 int i;
2877
2878 for (i = 0; i < num_permitted_opens; i++)
2879 if (permitted_opens[i].host_to_connect != NULL)
2880 xfree(permitted_opens[i].host_to_connect);
2881 num_permitted_opens = 0;
2882 }
2883
2884 void
2885 channel_clear_adm_permitted_opens(void)
2886 {
2887 int i;
2888
2889 for (i = 0; i < num_adm_permitted_opens; i++)
2890 if (permitted_adm_opens[i].host_to_connect != NULL)
2891 xfree(permitted_adm_opens[i].host_to_connect);
2892 num_adm_permitted_opens = 0;
2893 }
2894
2895 void
2896 channel_print_adm_permitted_opens(void)
2897 {
2898 int i;
2899
2900 printf("permitopen");
2901 if (num_adm_permitted_opens == 0) {
2902 printf(" any\n");
2903 return;
2904 }
2905 for (i = 0; i < num_adm_permitted_opens; i++)
2906 if (permitted_adm_opens[i].host_to_connect != NULL)
2907 printf(" %s:%d", permitted_adm_opens[i].host_to_connect,
2908 permitted_adm_opens[i].port_to_connect);
2909 printf("\n");
2910 }
2911
2912 /* Try to start non-blocking connect to next host in cctx list */
2913 static int
2914 connect_next(struct channel_connect *cctx)
2915 {
2916 int sock, saved_errno;
2917 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2918
2919 for (; cctx->ai; cctx->ai = cctx->ai->ai_next) {
2920 if (cctx->ai->ai_family != AF_INET &&
2921 cctx->ai->ai_family != AF_INET6)
2922 continue;
2923 if (getnameinfo(cctx->ai->ai_addr, cctx->ai->ai_addrlen,
2924 ntop, sizeof(ntop), strport, sizeof(strport),
2925 NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2926 error("connect_next: getnameinfo failed");
2927 continue;
2928 }
2929 if ((sock = socket_rdomain(cctx->ai->ai_family,
2930 cctx->ai->ai_socktype, cctx->ai->ai_protocol,
2931 channel_rdomain)) == -1) {
2932 if (cctx->ai->ai_next == NULL)
2933 error("socket: %.100s", strerror(errno));
2934 else
2935 verbose("socket: %.100s", strerror(errno));
2936 continue;
2937 }
2938 if (set_nonblock(sock) == -1)
2939 fatal("%s: set_nonblock(%d)", __func__, sock);
2940 if (connect(sock, cctx->ai->ai_addr,
2941 cctx->ai->ai_addrlen) == -1 && errno != EINPROGRESS) {
2942 debug("connect_next: host %.100s ([%.100s]:%s): "
2943 "%.100s", cctx->host, ntop, strport,
2944 strerror(errno));
2945 saved_errno = errno;
2946 close(sock);
2947 errno = saved_errno;
2948 continue; /* fail -- try next */
2949 }
2950 debug("connect_next: host %.100s ([%.100s]:%s) "
2951 "in progress, fd=%d", cctx->host, ntop, strport, sock);
2952 cctx->ai = cctx->ai->ai_next;
2953 set_nodelay(sock);
2954 return sock;
2955 }
2956 return -1;
2957 }
2958
2959 static void
2960 channel_connect_ctx_free(struct channel_connect *cctx)
2961 {
2962 xfree(cctx->host);
2963 if (cctx->aitop)
2964 freeaddrinfo(cctx->aitop);
2965 bzero(cctx, sizeof(*cctx));
2966 cctx->host = NULL;
2967 cctx->ai = cctx->aitop = NULL;
2968 }
2969
2970 /* Return CONNECTING channel to remote host, port */
2971 static Channel *
2972 connect_to(const char *host, u_short port, char *ctype, char *rname)
2973 {
2974 struct addrinfo hints;
2975 int gaierr;
2976 int sock = -1;
2977 char strport[NI_MAXSERV];
2978 struct channel_connect cctx;
2979 Channel *c;
2980
2981 memset(&cctx, 0, sizeof(cctx));
2982 memset(&hints, 0, sizeof(hints));
2983 hints.ai_family = IPv4or6;
2984 hints.ai_socktype = SOCK_STREAM;
2985 snprintf(strport, sizeof strport, "%d", port);
2986 if ((gaierr = getaddrinfo(host, strport, &hints, &cctx.aitop)) != 0) {
2987 error("connect_to %.100s: unknown host (%s)", host,
2988 ssh_gai_strerror(gaierr));
2989 return NULL;
2990 }
2991
2992 cctx.host = xstrdup(host);
2993 cctx.port = port;
2994 cctx.ai = cctx.aitop;
2995
2996 if ((sock = connect_next(&cctx)) == -1) {
2997 error("connect to %.100s port %d failed: %s",
2998 host, port, strerror(errno));
2999 channel_connect_ctx_free(&cctx);
3000 return NULL;
3001 }
3002 c = channel_new(ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1,
3003 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1);
3004 c->connect_ctx = cctx;
3005 return c;
3006 }
3007
3008 Channel *
3009 channel_connect_by_listen_address(u_short listen_port, char *ctype, char *rname)
3010 {
3011 int i;
3012
3013 for (i = 0; i < num_permitted_opens; i++) {
3014 if (permitted_opens[i].host_to_connect != NULL &&
3015 permitted_opens[i].listen_port == listen_port) {
3016 return connect_to(
3017 permitted_opens[i].host_to_connect,
3018 permitted_opens[i].port_to_connect, ctype, rname);
3019 }
3020 }
3021 error("WARNING: Server requests forwarding for unknown listen_port %d",
3022 listen_port);
3023 return NULL;
3024 }
3025
3026 /* Check if connecting to that port is permitted and connect. */
3027 Channel *
3028 channel_connect_to(const char *host, u_short port, char *ctype, char *rname)
3029 {
3030 int i, permit, permit_adm = 1;
3031
3032 permit = all_opens_permitted;
3033 if (!permit) {
3034 for (i = 0; i < num_permitted_opens; i++)
3035 if (permitted_opens[i].host_to_connect != NULL &&
3036 permitted_opens[i].port_to_connect == port &&
3037 strcmp(permitted_opens[i].host_to_connect, host) == 0)
3038 permit = 1;
3039 }
3040
3041 if (num_adm_permitted_opens > 0) {
3042 permit_adm = 0;
3043 for (i = 0; i < num_adm_permitted_opens; i++)
3044 if (permitted_adm_opens[i].host_to_connect != NULL &&
3045 permitted_adm_opens[i].port_to_connect == port &&
3046 strcmp(permitted_adm_opens[i].host_to_connect, host)
3047 == 0)
3048 permit_adm = 1;
3049 }
3050
3051 if (!permit || !permit_adm) {
3052 logit("Received request to connect to host %.100s port %d, "
3053 "but the request was denied.", host, port);
3054 return NULL;
3055 }
3056 return connect_to(host, port, ctype, rname);
3057 }
3058
3059 void
3060 channel_send_window_changes(void)
3061 {
3062 u_int i;
3063 struct winsize ws;
3064
3065 for (i = 0; i < channels_alloc; i++) {
3066 if (channels[i] == NULL || !channels[i]->client_tty ||
3067 channels[i]->type != SSH_CHANNEL_OPEN)
3068 continue;
3069 if (ioctl(channels[i]->rfd, TIOCGWINSZ, &ws) < 0)
3070 continue;
3071 channel_request_start(i, "window-change", 0);
3072 packet_put_int((u_int)ws.ws_col);
3073 packet_put_int((u_int)ws.ws_row);
3074 packet_put_int((u_int)ws.ws_xpixel);
3075 packet_put_int((u_int)ws.ws_ypixel);
3076 packet_send();
3077 }
3078 }
3079
3080 /* -- X11 forwarding */
3081
3082 /*
3083 * Creates an internet domain socket for listening for X11 connections.
3084 * Returns 0 and a suitable display number for the DISPLAY variable
3085 * stored in display_numberp , or -1 if an error occurs.
3086 */
3087 int
3088 x11_create_display_inet(int x11_display_offset, int x11_use_localhost,
3089 int single_connection, u_int *display_numberp, int **chanids)
3090 {
3091 Channel *nc = NULL;
3092 int display_number, sock;
3093 u_short port;
3094 struct addrinfo hints, *ai, *aitop;
3095 char strport[NI_MAXSERV];
3096 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
3097
3098 if (chanids == NULL)
3099 return -1;
3100
3101 for (display_number = x11_display_offset;
3102 display_number < MAX_DISPLAYS;
3103 display_number++) {
3104 port = 6000 + display_number;
3105 memset(&hints, 0, sizeof(hints));
3106 hints.ai_family = IPv4or6;
3107 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE;
3108 hints.ai_socktype = SOCK_STREAM;
3109 snprintf(strport, sizeof strport, "%d", port);
3110 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
3111 error("getaddrinfo: %.100s", ssh_gai_strerror(gaierr));
3112 return -1;
3113 }
3114 for (ai = aitop; ai; ai = ai->ai_next) {
3115 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
3116 continue;
3117 sock = socket_rdomain(ai->ai_family, ai->ai_socktype,
3118 ai->ai_protocol, channel_rdomain);
3119 if (sock < 0) {
3120 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
3121 error("socket: %.100s", strerror(errno));
3122 freeaddrinfo(aitop);
3123 return -1;
3124 } else {
3125 debug("x11_create_display_inet: Socket family %d not supported",
3126 ai->ai_family);
3127 continue;
3128 }
3129 }
3130 if (ai->ai_family == AF_INET6)
3131 sock_set_v6only(sock);
3132 if (x11_use_localhost)
3133 channel_set_reuseaddr(sock);
3134 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
3135 debug2("bind port %d: %.100s", port, strerror(errno));
3136 close(sock);
3137
3138 for (n = 0; n < num_socks; n++) {
3139 close(socks[n]);
3140 }
3141 num_socks = 0;
3142 break;
3143 }
3144 socks[num_socks++] = sock;
3145 if (num_socks == NUM_SOCKS)
3146 break;
3147 }
3148 freeaddrinfo(aitop);
3149 if (num_socks > 0)
3150 break;
3151 }
3152 if (display_number >= MAX_DISPLAYS) {
3153 error("Failed to allocate internet-domain X11 display socket.");
3154 return -1;
3155 }
3156 /* Start listening for connections on the socket. */
3157 for (n = 0; n < num_socks; n++) {
3158 sock = socks[n];
3159 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
3160 error("listen: %.100s", strerror(errno));
3161 close(sock);
3162 return -1;
3163 }
3164 }
3165
3166 /* Allocate a channel for each socket. */
3167 *chanids = xcalloc(num_socks + 1, sizeof(**chanids));
3168 for (n = 0; n < num_socks; n++) {
3169 sock = socks[n];
3170 nc = channel_new("x11 listener",
3171 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
3172 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
3173 0, "X11 inet listener", 1);
3174 nc->single_connection = single_connection;
3175 (*chanids)[n] = nc->self;
3176 }
3177 (*chanids)[n] = -1;
3178
3179 /* Return the display number for the DISPLAY environment variable. */
3180 *display_numberp = display_number;
3181 return (0);
3182 }
3183
3184 static int
3185 connect_local_xsocket_path(const char *pathname)
3186 {
3187 int sock;
3188 struct sockaddr_un addr;
3189
3190 sock = socket(AF_UNIX, SOCK_STREAM, 0);
3191 if (sock < 0)
3192 error("socket: %.100s", strerror(errno));
3193 memset(&addr, 0, sizeof(addr));
3194 addr.sun_family = AF_UNIX;
3195 strlcpy(addr.sun_path, pathname, sizeof addr.sun_path);
3196 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0)
3197 return sock;
3198 close(sock);
3199 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
3200 return -1;
3201 }
3202
3203 static int
3204 connect_local_xsocket(u_int dnr)
3205 {
3206 char buf[1024];
3207 snprintf(buf, sizeof buf, _PATH_UNIX_X, dnr);
3208 return connect_local_xsocket_path(buf);
3209 }
3210
3211 int
3212 x11_connect_display(void)
3213 {
3214 u_int display_number;
3215 const char *display;
3216 char buf[1024], *cp;
3217 struct addrinfo hints, *ai, *aitop;
3218 char strport[NI_MAXSERV];
3219 int gaierr, sock = 0;
3220
3221 /* Try to open a socket for the local X server. */
3222 display = getenv("DISPLAY");
3223 if (!display) {
3224 error("DISPLAY not set.");
3225 return -1;
3226 }
3227 /*
3228 * Now we decode the value of the DISPLAY variable and make a
3229 * connection to the real X server.
3230 */
3231
3232 /* Check if the display is from launchd. */
3233 #ifdef __APPLE__
3234 if (strncmp(display, "/tmp/launch", 11) == 0) {
3235 sock = connect_local_xsocket_path(display);
3236 if (sock < 0)
3237 return -1;
3238
3239 /* OK, we now have a connection to the display. */
3240 return sock;
3241 }
3242 #endif
3243 /*
3244 * Check if it is a unix domain socket. Unix domain displays are in
3245 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
3246 */
3247 if (strncmp(display, "unix:", 5) == 0 ||
3248 display[0] == ':') {
3249 /* Connect to the unix domain socket. */
3250 if (sscanf(strrchr(display, ':') + 1, "%u", &display_number) != 1) {
3251 error("Could not parse display number from DISPLAY: %.100s",
3252 display);
3253 return -1;
3254 }
3255 /* Create a socket. */
3256 sock = connect_local_xsocket(display_number);
3257 if (sock < 0)
3258 return -1;
3259
3260 /* OK, we now have a connection to the display. */
3261 return sock;
3262 }
3263 /*
3264 * Connect to an inet socket. The DISPLAY value is supposedly
3265 * hostname:d[.s], where hostname may also be numeric IP address.
3266 */
3267 strlcpy(buf, display, sizeof(buf));
3268 cp = strchr(buf, ':');
3269 if (!cp) {
3270 error("Could not find ':' in DISPLAY: %.100s", display);
3271 return -1;
3272 }
3273 *cp = 0;
3274 /* buf now contains the host name. But first we parse the display number. */
3275 if (sscanf(cp + 1, "%u", &display_number) != 1) {
3276 error("Could not parse display number from DISPLAY: %.100s",
3277 display);
3278 return -1;
3279 }
3280
3281 /* Look up the host address */
3282 memset(&hints, 0, sizeof(hints));
3283 hints.ai_family = IPv4or6;
3284 hints.ai_socktype = SOCK_STREAM;
3285 snprintf(strport, sizeof strport, "%u", 6000 + display_number);
3286 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
3287 error("%.100s: unknown host. (%s)", buf,
3288 ssh_gai_strerror(gaierr));
3289 return -1;
3290 }
3291 for (ai = aitop; ai; ai = ai->ai_next) {
3292 /* Create a socket. */
3293 sock = socket_rdomain(ai->ai_family, ai->ai_socktype,
3294 ai->ai_protocol, channel_rdomain);
3295 if (sock < 0) {
3296 debug2("socket: %.100s", strerror(errno));
3297 continue;
3298 }
3299 /* Connect it to the display. */
3300 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
3301 debug2("connect %.100s port %u: %.100s", buf,
3302 6000 + display_number, strerror(errno));
3303 close(sock);
3304 continue;
3305 }
3306 /* Success */
3307 break;
3308 }
3309 freeaddrinfo(aitop);
3310 if (!ai) {
3311 error("connect %.100s port %u: %.100s", buf, 6000 + display_number,
3312 strerror(errno));
3313 return -1;
3314 }
3315 set_nodelay(sock);
3316 return sock;
3317 }
3318
3319 /*
3320 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
3321 * the remote channel number. We should do whatever we want, and respond
3322 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
3323 */
3324
3325 /* ARGSUSED */
3326 void
3327 x11_input_open(int type, u_int32_t seq, void *ctxt)
3328 {
3329 Channel *c = NULL;
3330 int remote_id, sock = 0;
3331 char *remote_host;
3332
3333 debug("Received X11 open request.");
3334
3335 remote_id = packet_get_int();
3336
3337 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
3338 remote_host = packet_get_string(NULL);
3339 } else {
3340 remote_host = xstrdup("unknown (remote did not supply name)");
3341 }
3342 packet_check_eom();
3343
3344 /* Obtain a connection to the real X display. */
3345 sock = x11_connect_display();
3346 if (sock != -1) {
3347 /* Allocate a channel for this connection. */
3348 c = channel_new("connected x11 socket",
3349 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
3350 remote_host, 1);
3351 c->remote_id = remote_id;
3352 c->force_drain = 1;
3353 }
3354 xfree(remote_host);
3355 if (c == NULL) {
3356 /* Send refusal to the remote host. */
3357 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3358 packet_put_int(remote_id);
3359 } else {
3360 /* Send a confirmation to the remote host. */
3361 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
3362 packet_put_int(remote_id);
3363 packet_put_int(c->self);
3364 }
3365 packet_send();
3366 }
3367
3368 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
3369 /* ARGSUSED */
3370 void
3371 deny_input_open(int type, u_int32_t seq, void *ctxt)
3372 {
3373 int rchan = packet_get_int();
3374
3375 switch (type) {
3376 case SSH_SMSG_AGENT_OPEN:
3377 error("Warning: ssh server tried agent forwarding.");
3378 break;
3379 case SSH_SMSG_X11_OPEN:
3380 error("Warning: ssh server tried X11 forwarding.");
3381 break;
3382 default:
3383 error("deny_input_open: type %d", type);
3384 break;
3385 }
3386 error("Warning: this is probably a break-in attempt by a malicious server.");
3387 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3388 packet_put_int(rchan);
3389 packet_send();
3390 }
3391
3392 /*
3393 * Requests forwarding of X11 connections, generates fake authentication
3394 * data, and enables authentication spoofing.
3395 * This should be called in the client only.
3396 */
3397 void
3398 x11_request_forwarding_with_spoofing(int client_session_id, const char *disp,
3399 const char *proto, const char *data)
3400 {
3401 u_int data_len = (u_int) strlen(data) / 2;
3402 u_int i, value;
3403 char *new_data;
3404 int screen_number;
3405 const char *cp;
3406 u_int32_t rnd = 0;
3407
3408 if (x11_saved_display == NULL)
3409 x11_saved_display = xstrdup(disp);
3410 else if (strcmp(disp, x11_saved_display) != 0) {
3411 error("x11_request_forwarding_with_spoofing: different "
3412 "$DISPLAY already forwarded");
3413 return;
3414 }
3415
3416 cp = strchr(disp, ':');
3417 if (cp)
3418 cp = strchr(cp, '.');
3419 if (cp)
3420 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL);
3421 else
3422 screen_number = 0;
3423
3424 if (x11_saved_proto == NULL) {
3425 /* Save protocol name. */
3426 x11_saved_proto = xstrdup(proto);
3427 /*
3428 * Extract real authentication data and generate fake data
3429 * of the same length.
3430 */
3431 x11_saved_data = xmalloc(data_len);
3432 x11_fake_data = xmalloc(data_len);
3433 for (i = 0; i < data_len; i++) {
3434 if (sscanf(data + 2 * i, "%2x", &value) != 1)
3435 fatal("x11_request_forwarding: bad "
3436 "authentication data: %.100s", data);
3437 if (i % 4 == 0)
3438 rnd = arc4random();
3439 x11_saved_data[i] = value;
3440 x11_fake_data[i] = rnd & 0xff;
3441 rnd >>= 8;
3442 }
3443 x11_saved_data_len = data_len;
3444 x11_fake_data_len = data_len;
3445 }
3446
3447 /* Convert the fake data into hex. */
3448 new_data = tohex(x11_fake_data, data_len);
3449
3450 /* Send the request packet. */
3451 if (compat20) {
3452 channel_request_start(client_session_id, "x11-req", 0);
3453 packet_put_char(0); /* XXX bool single connection */
3454 } else {
3455 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
3456 }
3457 packet_put_cstring(proto);
3458 packet_put_cstring(new_data);
3459 packet_put_int(screen_number);
3460 packet_send();
3461 packet_write_wait();
3462 xfree(new_data);
3463 }
3464
3465
3466 /* -- agent forwarding */
3467
3468 /* Sends a message to the server to request authentication fd forwarding. */
3469
3470 void
3471 auth_request_forwarding(void)
3472 {
3473 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
3474 packet_send();
3475 packet_write_wait();
3476 }
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