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- dtucker@cvs.openbsd.org 2010/01/14 23:41:49
[openssh-git.git] / channels.c
blobe8589d8c4d148287f46e3cab4c850f12eb8ede39
1 /* $OpenBSD: channels.c,v 1.301 2010/01/11 01:39:46 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 /* helper */
167 static void port_open_helper(Channel *c, char *rtype);
168
169 /* non-blocking connect helpers */
170 static int connect_next(struct channel_connect *);
171 static void channel_connect_ctx_free(struct channel_connect *);
172
173 /* -- channel core */
174
175 Channel *
176 channel_by_id(int id)
177 {
178 Channel *c;
179
180 if (id < 0 || (u_int)id >= channels_alloc) {
181 logit("channel_by_id: %d: bad id", id);
182 return NULL;
183 }
184 c = channels[id];
185 if (c == NULL) {
186 logit("channel_by_id: %d: bad id: channel free", id);
187 return NULL;
188 }
189 return c;
190 }
191
192 /*
193 * Returns the channel if it is allowed to receive protocol messages.
194 * Private channels, like listening sockets, may not receive messages.
195 */
196 Channel *
197 channel_lookup(int id)
198 {
199 Channel *c;
200
201 if ((c = channel_by_id(id)) == NULL)
202 return (NULL);
203
204 switch (c->type) {
205 case SSH_CHANNEL_X11_OPEN:
206 case SSH_CHANNEL_LARVAL:
207 case SSH_CHANNEL_CONNECTING:
208 case SSH_CHANNEL_DYNAMIC:
209 case SSH_CHANNEL_OPENING:
210 case SSH_CHANNEL_OPEN:
211 case SSH_CHANNEL_INPUT_DRAINING:
212 case SSH_CHANNEL_OUTPUT_DRAINING:
213 return (c);
214 }
215 logit("Non-public channel %d, type %d.", id, c->type);
216 return (NULL);
217 }
218
219 /*
220 * Register filedescriptors for a channel, used when allocating a channel or
221 * when the channel consumer/producer is ready, e.g. shell exec'd
222 */
223 static void
224 channel_register_fds(Channel *c, int rfd, int wfd, int efd,
225 int extusage, int nonblock, int is_tty)
226 {
227 /* Update the maximum file descriptor value. */
228 channel_max_fd = MAX(channel_max_fd, rfd);
229 channel_max_fd = MAX(channel_max_fd, wfd);
230 channel_max_fd = MAX(channel_max_fd, efd);
231
232 if (rfd != -1)
233 fcntl(rfd, F_SETFD, FD_CLOEXEC);
234 if (wfd != -1 && wfd != rfd)
235 fcntl(wfd, F_SETFD, FD_CLOEXEC);
236 if (efd != -1 && efd != rfd && efd != wfd)
237 fcntl(efd, F_SETFD, FD_CLOEXEC);
238
239 c->rfd = rfd;
240 c->wfd = wfd;
241 c->sock = (rfd == wfd) ? rfd : -1;
242 c->ctl_fd = -1; /* XXX: set elsewhere */
243 c->efd = efd;
244 c->extended_usage = extusage;
245
246 if ((c->isatty = is_tty) != 0)
247 debug2("channel %d: rfd %d isatty", c->self, c->rfd);
248 c->wfd_isatty = is_tty || isatty(c->wfd);
249
250 /* enable nonblocking mode */
251 if (nonblock) {
252 if (rfd != -1)
253 set_nonblock(rfd);
254 if (wfd != -1)
255 set_nonblock(wfd);
256 if (efd != -1)
257 set_nonblock(efd);
258 }
259 }
260
261 /*
262 * Allocate a new channel object and set its type and socket. This will cause
263 * remote_name to be freed.
264 */
265 Channel *
266 channel_new(char *ctype, int type, int rfd, int wfd, int efd,
267 u_int window, u_int maxpack, int extusage, char *remote_name, int nonblock)
268 {
269 int found;
270 u_int i;
271 Channel *c;
272
273 /* Do initial allocation if this is the first call. */
274 if (channels_alloc == 0) {
275 channels_alloc = 10;
276 channels = xcalloc(channels_alloc, sizeof(Channel *));
277 for (i = 0; i < channels_alloc; i++)
278 channels[i] = NULL;
279 }
280 /* Try to find a free slot where to put the new channel. */
281 for (found = -1, i = 0; i < channels_alloc; i++)
282 if (channels[i] == NULL) {
283 /* Found a free slot. */
284 found = (int)i;
285 break;
286 }
287 if (found < 0) {
288 /* There are no free slots. Take last+1 slot and expand the array. */
289 found = channels_alloc;
290 if (channels_alloc > 10000)
291 fatal("channel_new: internal error: channels_alloc %d "
292 "too big.", channels_alloc);
293 channels = xrealloc(channels, channels_alloc + 10,
294 sizeof(Channel *));
295 channels_alloc += 10;
296 debug2("channel: expanding %d", channels_alloc);
297 for (i = found; i < channels_alloc; i++)
298 channels[i] = NULL;
299 }
300 /* Initialize and return new channel. */
301 c = channels[found] = xcalloc(1, sizeof(Channel));
302 buffer_init(&c->input);
303 buffer_init(&c->output);
304 buffer_init(&c->extended);
305 c->path = NULL;
306 c->ostate = CHAN_OUTPUT_OPEN;
307 c->istate = CHAN_INPUT_OPEN;
308 c->flags = 0;
309 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock, 0);
310 c->self = found;
311 c->type = type;
312 c->ctype = ctype;
313 c->local_window = window;
314 c->local_window_max = window;
315 c->local_consumed = 0;
316 c->local_maxpacket = maxpack;
317 c->remote_id = -1;
318 c->remote_name = xstrdup(remote_name);
319 c->remote_window = 0;
320 c->remote_maxpacket = 0;
321 c->force_drain = 0;
322 c->single_connection = 0;
323 c->detach_user = NULL;
324 c->detach_close = 0;
325 c->open_confirm = NULL;
326 c->open_confirm_ctx = NULL;
327 c->input_filter = NULL;
328 c->output_filter = NULL;
329 c->filter_ctx = NULL;
330 c->filter_cleanup = NULL;
331 c->delayed = 1; /* prevent call to channel_post handler */
332 TAILQ_INIT(&c->status_confirms);
333 debug("channel %d: new [%s]", found, remote_name);
334 return c;
335 }
336
337 static int
338 channel_find_maxfd(void)
339 {
340 u_int i;
341 int max = 0;
342 Channel *c;
343
344 for (i = 0; i < channels_alloc; i++) {
345 c = channels[i];
346 if (c != NULL) {
347 max = MAX(max, c->rfd);
348 max = MAX(max, c->wfd);
349 max = MAX(max, c->efd);
350 }
351 }
352 return max;
353 }
354
355 int
356 channel_close_fd(int *fdp)
357 {
358 int ret = 0, fd = *fdp;
359
360 if (fd != -1) {
361 ret = close(fd);
362 *fdp = -1;
363 if (fd == channel_max_fd)
364 channel_max_fd = channel_find_maxfd();
365 }
366 return ret;
367 }
368
369 /* Close all channel fd/socket. */
370 static void
371 channel_close_fds(Channel *c)
372 {
373 debug3("channel %d: close_fds r %d w %d e %d c %d",
374 c->self, c->rfd, c->wfd, c->efd, c->ctl_fd);
375
376 channel_close_fd(&c->sock);
377 channel_close_fd(&c->ctl_fd);
378 channel_close_fd(&c->rfd);
379 channel_close_fd(&c->wfd);
380 channel_close_fd(&c->efd);
381 }
382
383 /* Free the channel and close its fd/socket. */
384 void
385 channel_free(Channel *c)
386 {
387 char *s;
388 u_int i, n;
389 struct channel_confirm *cc;
390
391 for (n = 0, i = 0; i < channels_alloc; i++)
392 if (channels[i])
393 n++;
394 debug("channel %d: free: %s, nchannels %u", c->self,
395 c->remote_name ? c->remote_name : "???", n);
396
397 s = channel_open_message();
398 debug3("channel %d: status: %s", c->self, s);
399 xfree(s);
400
401 if (c->sock != -1)
402 shutdown(c->sock, SHUT_RDWR);
403 if (c->ctl_fd != -1)
404 shutdown(c->ctl_fd, SHUT_RDWR);
405 channel_close_fds(c);
406 buffer_free(&c->input);
407 buffer_free(&c->output);
408 buffer_free(&c->extended);
409 if (c->remote_name) {
410 xfree(c->remote_name);
411 c->remote_name = NULL;
412 }
413 if (c->path) {
414 xfree(c->path);
415 c->path = NULL;
416 }
417 while ((cc = TAILQ_FIRST(&c->status_confirms)) != NULL) {
418 if (cc->abandon_cb != NULL)
419 cc->abandon_cb(c, cc->ctx);
420 TAILQ_REMOVE(&c->status_confirms, cc, entry);
421 bzero(cc, sizeof(*cc));
422 xfree(cc);
423 }
424 if (c->filter_cleanup != NULL && c->filter_ctx != NULL)
425 c->filter_cleanup(c->self, c->filter_ctx);
426 channels[c->self] = NULL;
427 xfree(c);
428 }
429
430 void
431 channel_free_all(void)
432 {
433 u_int i;
434
435 for (i = 0; i < channels_alloc; i++)
436 if (channels[i] != NULL)
437 channel_free(channels[i]);
438 }
439
440 /*
441 * Closes the sockets/fds of all channels. This is used to close extra file
442 * descriptors after a fork.
443 */
444 void
445 channel_close_all(void)
446 {
447 u_int i;
448
449 for (i = 0; i < channels_alloc; i++)
450 if (channels[i] != NULL)
451 channel_close_fds(channels[i]);
452 }
453
454 /*
455 * Stop listening to channels.
456 */
457 void
458 channel_stop_listening(void)
459 {
460 u_int i;
461 Channel *c;
462
463 for (i = 0; i < channels_alloc; i++) {
464 c = channels[i];
465 if (c != NULL) {
466 switch (c->type) {
467 case SSH_CHANNEL_AUTH_SOCKET:
468 case SSH_CHANNEL_PORT_LISTENER:
469 case SSH_CHANNEL_RPORT_LISTENER:
470 case SSH_CHANNEL_X11_LISTENER:
471 channel_close_fd(&c->sock);
472 channel_free(c);
473 break;
474 }
475 }
476 }
477 }
478
479 /*
480 * Returns true if no channel has too much buffered data, and false if one or
481 * more channel is overfull.
482 */
483 int
484 channel_not_very_much_buffered_data(void)
485 {
486 u_int i;
487 Channel *c;
488
489 for (i = 0; i < channels_alloc; i++) {
490 c = channels[i];
491 if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
492 #if 0
493 if (!compat20 &&
494 buffer_len(&c->input) > packet_get_maxsize()) {
495 debug2("channel %d: big input buffer %d",
496 c->self, buffer_len(&c->input));
497 return 0;
498 }
499 #endif
500 if (buffer_len(&c->output) > packet_get_maxsize()) {
501 debug2("channel %d: big output buffer %u > %u",
502 c->self, buffer_len(&c->output),
503 packet_get_maxsize());
504 return 0;
505 }
506 }
507 }
508 return 1;
509 }
510
511 /* Returns true if any channel is still open. */
512 int
513 channel_still_open(void)
514 {
515 u_int i;
516 Channel *c;
517
518 for (i = 0; i < channels_alloc; i++) {
519 c = channels[i];
520 if (c == NULL)
521 continue;
522 switch (c->type) {
523 case SSH_CHANNEL_X11_LISTENER:
524 case SSH_CHANNEL_PORT_LISTENER:
525 case SSH_CHANNEL_RPORT_LISTENER:
526 case SSH_CHANNEL_CLOSED:
527 case SSH_CHANNEL_AUTH_SOCKET:
528 case SSH_CHANNEL_DYNAMIC:
529 case SSH_CHANNEL_CONNECTING:
530 case SSH_CHANNEL_ZOMBIE:
531 continue;
532 case SSH_CHANNEL_LARVAL:
533 if (!compat20)
534 fatal("cannot happen: SSH_CHANNEL_LARVAL");
535 continue;
536 case SSH_CHANNEL_OPENING:
537 case SSH_CHANNEL_OPEN:
538 case SSH_CHANNEL_X11_OPEN:
539 return 1;
540 case SSH_CHANNEL_INPUT_DRAINING:
541 case SSH_CHANNEL_OUTPUT_DRAINING:
542 if (!compat13)
543 fatal("cannot happen: OUT_DRAIN");
544 return 1;
545 default:
546 fatal("channel_still_open: bad channel type %d", c->type);
547 /* NOTREACHED */
548 }
549 }
550 return 0;
551 }
552
553 /* Returns the id of an open channel suitable for keepaliving */
554 int
555 channel_find_open(void)
556 {
557 u_int i;
558 Channel *c;
559
560 for (i = 0; i < channels_alloc; i++) {
561 c = channels[i];
562 if (c == NULL || c->remote_id < 0)
563 continue;
564 switch (c->type) {
565 case SSH_CHANNEL_CLOSED:
566 case SSH_CHANNEL_DYNAMIC:
567 case SSH_CHANNEL_X11_LISTENER:
568 case SSH_CHANNEL_PORT_LISTENER:
569 case SSH_CHANNEL_RPORT_LISTENER:
570 case SSH_CHANNEL_OPENING:
571 case SSH_CHANNEL_CONNECTING:
572 case SSH_CHANNEL_ZOMBIE:
573 continue;
574 case SSH_CHANNEL_LARVAL:
575 case SSH_CHANNEL_AUTH_SOCKET:
576 case SSH_CHANNEL_OPEN:
577 case SSH_CHANNEL_X11_OPEN:
578 return i;
579 case SSH_CHANNEL_INPUT_DRAINING:
580 case SSH_CHANNEL_OUTPUT_DRAINING:
581 if (!compat13)
582 fatal("cannot happen: OUT_DRAIN");
583 return i;
584 default:
585 fatal("channel_find_open: bad channel type %d", c->type);
586 /* NOTREACHED */
587 }
588 }
589 return -1;
590 }
591
592
593 /*
594 * Returns a message describing the currently open forwarded connections,
595 * suitable for sending to the client. The message contains crlf pairs for
596 * newlines.
597 */
598 char *
599 channel_open_message(void)
600 {
601 Buffer buffer;
602 Channel *c;
603 char buf[1024], *cp;
604 u_int i;
605
606 buffer_init(&buffer);
607 snprintf(buf, sizeof buf, "The following connections are open:\r\n");
608 buffer_append(&buffer, buf, strlen(buf));
609 for (i = 0; i < channels_alloc; i++) {
610 c = channels[i];
611 if (c == NULL)
612 continue;
613 switch (c->type) {
614 case SSH_CHANNEL_X11_LISTENER:
615 case SSH_CHANNEL_PORT_LISTENER:
616 case SSH_CHANNEL_RPORT_LISTENER:
617 case SSH_CHANNEL_CLOSED:
618 case SSH_CHANNEL_AUTH_SOCKET:
619 case SSH_CHANNEL_ZOMBIE:
620 continue;
621 case SSH_CHANNEL_LARVAL:
622 case SSH_CHANNEL_OPENING:
623 case SSH_CHANNEL_CONNECTING:
624 case SSH_CHANNEL_DYNAMIC:
625 case SSH_CHANNEL_OPEN:
626 case SSH_CHANNEL_X11_OPEN:
627 case SSH_CHANNEL_INPUT_DRAINING:
628 case SSH_CHANNEL_OUTPUT_DRAINING:
629 snprintf(buf, sizeof buf,
630 " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d cfd %d)\r\n",
631 c->self, c->remote_name,
632 c->type, c->remote_id,
633 c->istate, buffer_len(&c->input),
634 c->ostate, buffer_len(&c->output),
635 c->rfd, c->wfd, c->ctl_fd);
636 buffer_append(&buffer, buf, strlen(buf));
637 continue;
638 default:
639 fatal("channel_open_message: bad channel type %d", c->type);
640 /* NOTREACHED */
641 }
642 }
643 buffer_append(&buffer, "\0", 1);
644 cp = xstrdup(buffer_ptr(&buffer));
645 buffer_free(&buffer);
646 return cp;
647 }
648
649 void
650 channel_send_open(int id)
651 {
652 Channel *c = channel_lookup(id);
653
654 if (c == NULL) {
655 logit("channel_send_open: %d: bad id", id);
656 return;
657 }
658 debug2("channel %d: send open", id);
659 packet_start(SSH2_MSG_CHANNEL_OPEN);
660 packet_put_cstring(c->ctype);
661 packet_put_int(c->self);
662 packet_put_int(c->local_window);
663 packet_put_int(c->local_maxpacket);
664 packet_send();
665 }
666
667 void
668 channel_request_start(int id, char *service, int wantconfirm)
669 {
670 Channel *c = channel_lookup(id);
671
672 if (c == NULL) {
673 logit("channel_request_start: %d: unknown channel id", id);
674 return;
675 }
676 debug2("channel %d: request %s confirm %d", id, service, wantconfirm);
677 packet_start(SSH2_MSG_CHANNEL_REQUEST);
678 packet_put_int(c->remote_id);
679 packet_put_cstring(service);
680 packet_put_char(wantconfirm);
681 }
682
683 void
684 channel_register_status_confirm(int id, channel_confirm_cb *cb,
685 channel_confirm_abandon_cb *abandon_cb, void *ctx)
686 {
687 struct channel_confirm *cc;
688 Channel *c;
689
690 if ((c = channel_lookup(id)) == NULL)
691 fatal("channel_register_expect: %d: bad id", id);
692
693 cc = xmalloc(sizeof(*cc));
694 cc->cb = cb;
695 cc->abandon_cb = abandon_cb;
696 cc->ctx = ctx;
697 TAILQ_INSERT_TAIL(&c->status_confirms, cc, entry);
698 }
699
700 void
701 channel_register_open_confirm(int id, channel_callback_fn *fn, void *ctx)
702 {
703 Channel *c = channel_lookup(id);
704
705 if (c == NULL) {
706 logit("channel_register_open_confirm: %d: bad id", id);
707 return;
708 }
709 c->open_confirm = fn;
710 c->open_confirm_ctx = ctx;
711 }
712
713 void
714 channel_register_cleanup(int id, channel_callback_fn *fn, int do_close)
715 {
716 Channel *c = channel_by_id(id);
717
718 if (c == NULL) {
719 logit("channel_register_cleanup: %d: bad id", id);
720 return;
721 }
722 c->detach_user = fn;
723 c->detach_close = do_close;
724 }
725
726 void
727 channel_cancel_cleanup(int id)
728 {
729 Channel *c = channel_by_id(id);
730
731 if (c == NULL) {
732 logit("channel_cancel_cleanup: %d: bad id", id);
733 return;
734 }
735 c->detach_user = NULL;
736 c->detach_close = 0;
737 }
738
739 void
740 channel_register_filter(int id, channel_infilter_fn *ifn,
741 channel_outfilter_fn *ofn, channel_filter_cleanup_fn *cfn, void *ctx)
742 {
743 Channel *c = channel_lookup(id);
744
745 if (c == NULL) {
746 logit("channel_register_filter: %d: bad id", id);
747 return;
748 }
749 c->input_filter = ifn;
750 c->output_filter = ofn;
751 c->filter_ctx = ctx;
752 c->filter_cleanup = cfn;
753 }
754
755 void
756 channel_set_fds(int id, int rfd, int wfd, int efd,
757 int extusage, int nonblock, int is_tty, u_int window_max)
758 {
759 Channel *c = channel_lookup(id);
760
761 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
762 fatal("channel_activate for non-larval channel %d.", id);
763 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock, is_tty);
764 c->type = SSH_CHANNEL_OPEN;
765 c->local_window = c->local_window_max = window_max;
766 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
767 packet_put_int(c->remote_id);
768 packet_put_int(c->local_window);
769 packet_send();
770 }
771
772 /*
773 * 'channel_pre*' are called just before select() to add any bits relevant to
774 * channels in the select bitmasks.
775 */
776 /*
777 * 'channel_post*': perform any appropriate operations for channels which
778 * have events pending.
779 */
780 typedef void chan_fn(Channel *c, fd_set *readset, fd_set *writeset);
781 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
782 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
783
784 /* ARGSUSED */
785 static void
786 channel_pre_listener(Channel *c, fd_set *readset, fd_set *writeset)
787 {
788 FD_SET(c->sock, readset);
789 }
790
791 /* ARGSUSED */
792 static void
793 channel_pre_connecting(Channel *c, fd_set *readset, fd_set *writeset)
794 {
795 debug3("channel %d: waiting for connection", c->self);
796 FD_SET(c->sock, writeset);
797 }
798
799 static void
800 channel_pre_open_13(Channel *c, fd_set *readset, fd_set *writeset)
801 {
802 if (buffer_len(&c->input) < packet_get_maxsize())
803 FD_SET(c->sock, readset);
804 if (buffer_len(&c->output) > 0)
805 FD_SET(c->sock, writeset);
806 }
807
808 static void
809 channel_pre_open(Channel *c, fd_set *readset, fd_set *writeset)
810 {
811 u_int limit = compat20 ? c->remote_window : packet_get_maxsize();
812
813 if (c->istate == CHAN_INPUT_OPEN &&
814 limit > 0 &&
815 buffer_len(&c->input) < limit &&
816 buffer_check_alloc(&c->input, CHAN_RBUF))
817 FD_SET(c->rfd, readset);
818 if (c->ostate == CHAN_OUTPUT_OPEN ||
819 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
820 if (buffer_len(&c->output) > 0) {
821 FD_SET(c->wfd, writeset);
822 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
823 if (CHANNEL_EFD_OUTPUT_ACTIVE(c))
824 debug2("channel %d: obuf_empty delayed efd %d/(%d)",
825 c->self, c->efd, buffer_len(&c->extended));
826 else
827 chan_obuf_empty(c);
828 }
829 }
830 /** XXX check close conditions, too */
831 if (compat20 && c->efd != -1 &&
832 !(c->istate == CHAN_INPUT_CLOSED && c->ostate == CHAN_OUTPUT_CLOSED)) {
833 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
834 buffer_len(&c->extended) > 0)
835 FD_SET(c->efd, writeset);
836 else if (!(c->flags & CHAN_EOF_SENT) &&
837 c->extended_usage == CHAN_EXTENDED_READ &&
838 buffer_len(&c->extended) < c->remote_window)
839 FD_SET(c->efd, readset);
840 }
841 /* XXX: What about efd? races? */
842 if (compat20 && c->ctl_fd != -1 &&
843 c->istate == CHAN_INPUT_OPEN && c->ostate == CHAN_OUTPUT_OPEN)
844 FD_SET(c->ctl_fd, readset);
845 }
846
847 /* ARGSUSED */
848 static void
849 channel_pre_input_draining(Channel *c, fd_set *readset, fd_set *writeset)
850 {
851 if (buffer_len(&c->input) == 0) {
852 packet_start(SSH_MSG_CHANNEL_CLOSE);
853 packet_put_int(c->remote_id);
854 packet_send();
855 c->type = SSH_CHANNEL_CLOSED;
856 debug2("channel %d: closing after input drain.", c->self);
857 }
858 }
859
860 /* ARGSUSED */
861 static void
862 channel_pre_output_draining(Channel *c, fd_set *readset, fd_set *writeset)
863 {
864 if (buffer_len(&c->output) == 0)
865 chan_mark_dead(c);
866 else
867 FD_SET(c->sock, writeset);
868 }
869
870 /*
871 * This is a special state for X11 authentication spoofing. An opened X11
872 * connection (when authentication spoofing is being done) remains in this
873 * state until the first packet has been completely read. The authentication
874 * data in that packet is then substituted by the real data if it matches the
875 * fake data, and the channel is put into normal mode.
876 * XXX All this happens at the client side.
877 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
878 */
879 static int
880 x11_open_helper(Buffer *b)
881 {
882 u_char *ucp;
883 u_int proto_len, data_len;
884
885 /* Check if the fixed size part of the packet is in buffer. */
886 if (buffer_len(b) < 12)
887 return 0;
888
889 /* Parse the lengths of variable-length fields. */
890 ucp = buffer_ptr(b);
891 if (ucp[0] == 0x42) { /* Byte order MSB first. */
892 proto_len = 256 * ucp[6] + ucp[7];
893 data_len = 256 * ucp[8] + ucp[9];
894 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
895 proto_len = ucp[6] + 256 * ucp[7];
896 data_len = ucp[8] + 256 * ucp[9];
897 } else {
898 debug2("Initial X11 packet contains bad byte order byte: 0x%x",
899 ucp[0]);
900 return -1;
901 }
902
903 /* Check if the whole packet is in buffer. */
904 if (buffer_len(b) <
905 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
906 return 0;
907
908 /* Check if authentication protocol matches. */
909 if (proto_len != strlen(x11_saved_proto) ||
910 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
911 debug2("X11 connection uses different authentication protocol.");
912 return -1;
913 }
914 /* Check if authentication data matches our fake data. */
915 if (data_len != x11_fake_data_len ||
916 memcmp(ucp + 12 + ((proto_len + 3) & ~3),
917 x11_fake_data, x11_fake_data_len) != 0) {
918 debug2("X11 auth data does not match fake data.");
919 return -1;
920 }
921 /* Check fake data length */
922 if (x11_fake_data_len != x11_saved_data_len) {
923 error("X11 fake_data_len %d != saved_data_len %d",
924 x11_fake_data_len, x11_saved_data_len);
925 return -1;
926 }
927 /*
928 * Received authentication protocol and data match
929 * our fake data. Substitute the fake data with real
930 * data.
931 */
932 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
933 x11_saved_data, x11_saved_data_len);
934 return 1;
935 }
936
937 static void
938 channel_pre_x11_open_13(Channel *c, fd_set *readset, fd_set *writeset)
939 {
940 int ret = x11_open_helper(&c->output);
941
942 if (ret == 1) {
943 /* Start normal processing for the channel. */
944 c->type = SSH_CHANNEL_OPEN;
945 channel_pre_open_13(c, readset, writeset);
946 } else if (ret == -1) {
947 /*
948 * We have received an X11 connection that has bad
949 * authentication information.
950 */
951 logit("X11 connection rejected because of wrong authentication.");
952 buffer_clear(&c->input);
953 buffer_clear(&c->output);
954 channel_close_fd(&c->sock);
955 c->sock = -1;
956 c->type = SSH_CHANNEL_CLOSED;
957 packet_start(SSH_MSG_CHANNEL_CLOSE);
958 packet_put_int(c->remote_id);
959 packet_send();
960 }
961 }
962
963 static void
964 channel_pre_x11_open(Channel *c, fd_set *readset, fd_set *writeset)
965 {
966 int ret = x11_open_helper(&c->output);
967
968 /* c->force_drain = 1; */
969
970 if (ret == 1) {
971 c->type = SSH_CHANNEL_OPEN;
972 channel_pre_open(c, readset, writeset);
973 } else if (ret == -1) {
974 logit("X11 connection rejected because of wrong authentication.");
975 debug2("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
976 chan_read_failed(c);
977 buffer_clear(&c->input);
978 chan_ibuf_empty(c);
979 buffer_clear(&c->output);
980 /* for proto v1, the peer will send an IEOF */
981 if (compat20)
982 chan_write_failed(c);
983 else
984 c->type = SSH_CHANNEL_OPEN;
985 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
986 }
987 }
988
989 /* try to decode a socks4 header */
990 /* ARGSUSED */
991 static int
992 channel_decode_socks4(Channel *c, fd_set *readset, fd_set *writeset)
993 {
994 char *p, *host;
995 u_int len, have, i, found, need;
996 char username[256];
997 struct {
998 u_int8_t version;
999 u_int8_t command;
1000 u_int16_t dest_port;
1001 struct in_addr dest_addr;
1002 } s4_req, s4_rsp;
1003
1004 debug2("channel %d: decode socks4", c->self);
1005
1006 have = buffer_len(&c->input);
1007 len = sizeof(s4_req);
1008 if (have < len)
1009 return 0;
1010 p = buffer_ptr(&c->input);
1011
1012 need = 1;
1013 /* SOCKS4A uses an invalid IP address 0.0.0.x */
1014 if (p[4] == 0 && p[5] == 0 && p[6] == 0 && p[7] != 0) {
1015 debug2("channel %d: socks4a request", c->self);
1016 /* ... and needs an extra string (the hostname) */
1017 need = 2;
1018 }
1019 /* Check for terminating NUL on the string(s) */
1020 for (found = 0, i = len; i < have; i++) {
1021 if (p[i] == '\0') {
1022 found++;
1023 if (found == need)
1024 break;
1025 }
1026 if (i > 1024) {
1027 /* the peer is probably sending garbage */
1028 debug("channel %d: decode socks4: too long",
1029 c->self);
1030 return -1;
1031 }
1032 }
1033 if (found < need)
1034 return 0;
1035 buffer_get(&c->input, (char *)&s4_req.version, 1);
1036 buffer_get(&c->input, (char *)&s4_req.command, 1);
1037 buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
1038 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
1039 have = buffer_len(&c->input);
1040 p = buffer_ptr(&c->input);
1041 len = strlen(p);
1042 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
1043 len++; /* trailing '\0' */
1044 if (len > have)
1045 fatal("channel %d: decode socks4: len %d > have %d",
1046 c->self, len, have);
1047 strlcpy(username, p, sizeof(username));
1048 buffer_consume(&c->input, len);
1049
1050 if (c->path != NULL) {
1051 xfree(c->path);
1052 c->path = NULL;
1053 }
1054 if (need == 1) { /* SOCKS4: one string */
1055 host = inet_ntoa(s4_req.dest_addr);
1056 c->path = xstrdup(host);
1057 } else { /* SOCKS4A: two strings */
1058 have = buffer_len(&c->input);
1059 p = buffer_ptr(&c->input);
1060 len = strlen(p);
1061 debug2("channel %d: decode socks4a: host %s/%d",
1062 c->self, p, len);
1063 len++; /* trailing '\0' */
1064 if (len > have)
1065 fatal("channel %d: decode socks4a: len %d > have %d",
1066 c->self, len, have);
1067 if (len > NI_MAXHOST) {
1068 error("channel %d: hostname \"%.100s\" too long",
1069 c->self, p);
1070 return -1;
1071 }
1072 c->path = xstrdup(p);
1073 buffer_consume(&c->input, len);
1074 }
1075 c->host_port = ntohs(s4_req.dest_port);
1076
1077 debug2("channel %d: dynamic request: socks4 host %s port %u command %u",
1078 c->self, c->path, c->host_port, s4_req.command);
1079
1080 if (s4_req.command != 1) {
1081 debug("channel %d: cannot handle: %s cn %d",
1082 c->self, need == 1 ? "SOCKS4" : "SOCKS4A", s4_req.command);
1083 return -1;
1084 }
1085 s4_rsp.version = 0; /* vn: 0 for reply */
1086 s4_rsp.command = 90; /* cd: req granted */
1087 s4_rsp.dest_port = 0; /* ignored */
1088 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
1089 buffer_append(&c->output, &s4_rsp, sizeof(s4_rsp));
1090 return 1;
1091 }
1092
1093 /* try to decode a socks5 header */
1094 #define SSH_SOCKS5_AUTHDONE 0x1000
1095 #define SSH_SOCKS5_NOAUTH 0x00
1096 #define SSH_SOCKS5_IPV4 0x01
1097 #define SSH_SOCKS5_DOMAIN 0x03
1098 #define SSH_SOCKS5_IPV6 0x04
1099 #define SSH_SOCKS5_CONNECT 0x01
1100 #define SSH_SOCKS5_SUCCESS 0x00
1101
1102 /* ARGSUSED */
1103 static int
1104 channel_decode_socks5(Channel *c, fd_set *readset, fd_set *writeset)
1105 {
1106 struct {
1107 u_int8_t version;
1108 u_int8_t command;
1109 u_int8_t reserved;
1110 u_int8_t atyp;
1111 } s5_req, s5_rsp;
1112 u_int16_t dest_port;
1113 u_char *p, dest_addr[255+1], ntop[INET6_ADDRSTRLEN];
1114 u_int have, need, i, found, nmethods, addrlen, af;
1115
1116 debug2("channel %d: decode socks5", c->self);
1117 p = buffer_ptr(&c->input);
1118 if (p[0] != 0x05)
1119 return -1;
1120 have = buffer_len(&c->input);
1121 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) {
1122 /* format: ver | nmethods | methods */
1123 if (have < 2)
1124 return 0;
1125 nmethods = p[1];
1126 if (have < nmethods + 2)
1127 return 0;
1128 /* look for method: "NO AUTHENTICATION REQUIRED" */
1129 for (found = 0, i = 2; i < nmethods + 2; i++) {
1130 if (p[i] == SSH_SOCKS5_NOAUTH) {
1131 found = 1;
1132 break;
1133 }
1134 }
1135 if (!found) {
1136 debug("channel %d: method SSH_SOCKS5_NOAUTH not found",
1137 c->self);
1138 return -1;
1139 }
1140 buffer_consume(&c->input, nmethods + 2);
1141 buffer_put_char(&c->output, 0x05); /* version */
1142 buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH); /* method */
1143 FD_SET(c->sock, writeset);
1144 c->flags |= SSH_SOCKS5_AUTHDONE;
1145 debug2("channel %d: socks5 auth done", c->self);
1146 return 0; /* need more */
1147 }
1148 debug2("channel %d: socks5 post auth", c->self);
1149 if (have < sizeof(s5_req)+1)
1150 return 0; /* need more */
1151 memcpy(&s5_req, p, sizeof(s5_req));
1152 if (s5_req.version != 0x05 ||
1153 s5_req.command != SSH_SOCKS5_CONNECT ||
1154 s5_req.reserved != 0x00) {
1155 debug2("channel %d: only socks5 connect supported", c->self);
1156 return -1;
1157 }
1158 switch (s5_req.atyp){
1159 case SSH_SOCKS5_IPV4:
1160 addrlen = 4;
1161 af = AF_INET;
1162 break;
1163 case SSH_SOCKS5_DOMAIN:
1164 addrlen = p[sizeof(s5_req)];
1165 af = -1;
1166 break;
1167 case SSH_SOCKS5_IPV6:
1168 addrlen = 16;
1169 af = AF_INET6;
1170 break;
1171 default:
1172 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp);
1173 return -1;
1174 }
1175 need = sizeof(s5_req) + addrlen + 2;
1176 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1177 need++;
1178 if (have < need)
1179 return 0;
1180 buffer_consume(&c->input, sizeof(s5_req));
1181 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1182 buffer_consume(&c->input, 1); /* host string length */
1183 buffer_get(&c->input, (char *)&dest_addr, addrlen);
1184 buffer_get(&c->input, (char *)&dest_port, 2);
1185 dest_addr[addrlen] = '\0';
1186 if (c->path != NULL) {
1187 xfree(c->path);
1188 c->path = NULL;
1189 }
1190 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) {
1191 if (addrlen >= NI_MAXHOST) {
1192 error("channel %d: dynamic request: socks5 hostname "
1193 "\"%.100s\" too long", c->self, dest_addr);
1194 return -1;
1195 }
1196 c->path = xstrdup(dest_addr);
1197 } else {
1198 if (inet_ntop(af, dest_addr, ntop, sizeof(ntop)) == NULL)
1199 return -1;
1200 c->path = xstrdup(ntop);
1201 }
1202 c->host_port = ntohs(dest_port);
1203
1204 debug2("channel %d: dynamic request: socks5 host %s port %u command %u",
1205 c->self, c->path, c->host_port, s5_req.command);
1206
1207 s5_rsp.version = 0x05;
1208 s5_rsp.command = SSH_SOCKS5_SUCCESS;
1209 s5_rsp.reserved = 0; /* ignored */
1210 s5_rsp.atyp = SSH_SOCKS5_IPV4;
1211 ((struct in_addr *)&dest_addr)->s_addr = INADDR_ANY;
1212 dest_port = 0; /* ignored */
1213
1214 buffer_append(&c->output, &s5_rsp, sizeof(s5_rsp));
1215 buffer_append(&c->output, &dest_addr, sizeof(struct in_addr));
1216 buffer_append(&c->output, &dest_port, sizeof(dest_port));
1217 return 1;
1218 }
1219
1220 Channel *
1221 channel_connect_stdio_fwd(const char *host_to_connect, u_short port_to_connect)
1222 {
1223 Channel *c;
1224 int in, out;
1225
1226 debug("channel_connect_stdio_fwd %s:%d", host_to_connect,
1227 port_to_connect);
1228
1229 in = dup(STDIN_FILENO);
1230 out = dup(STDOUT_FILENO);
1231 if (in < 0 || out < 0)
1232 fatal("channel_connect_stdio_fwd: dup() in/out failed");
1233
1234 c = channel_new("stdio-forward", SSH_CHANNEL_OPENING, in, out,
1235 -1, CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
1236 0, "stdio-forward", /*nonblock*/0);
1237
1238 c->path = xstrdup(host_to_connect);
1239 c->host_port = port_to_connect;
1240 c->listening_port = 0;
1241 c->force_drain = 1;
1242
1243 channel_register_fds(c, in, out, -1, 0, 1, 0);
1244 port_open_helper(c, "direct-tcpip");
1245
1246 return c;
1247 }
1248
1249 /* dynamic port forwarding */
1250 static void
1251 channel_pre_dynamic(Channel *c, fd_set *readset, fd_set *writeset)
1252 {
1253 u_char *p;
1254 u_int have;
1255 int ret;
1256
1257 have = buffer_len(&c->input);
1258 debug2("channel %d: pre_dynamic: have %d", c->self, have);
1259 /* buffer_dump(&c->input); */
1260 /* check if the fixed size part of the packet is in buffer. */
1261 if (have < 3) {
1262 /* need more */
1263 FD_SET(c->sock, readset);
1264 return;
1265 }
1266 /* try to guess the protocol */
1267 p = buffer_ptr(&c->input);
1268 switch (p[0]) {
1269 case 0x04:
1270 ret = channel_decode_socks4(c, readset, writeset);
1271 break;
1272 case 0x05:
1273 ret = channel_decode_socks5(c, readset, writeset);
1274 break;
1275 default:
1276 ret = -1;
1277 break;
1278 }
1279 if (ret < 0) {
1280 chan_mark_dead(c);
1281 } else if (ret == 0) {
1282 debug2("channel %d: pre_dynamic: need more", c->self);
1283 /* need more */
1284 FD_SET(c->sock, readset);
1285 } else {
1286 /* switch to the next state */
1287 c->type = SSH_CHANNEL_OPENING;
1288 port_open_helper(c, "direct-tcpip");
1289 }
1290 }
1291
1292 /* This is our fake X11 server socket. */
1293 /* ARGSUSED */
1294 static void
1295 channel_post_x11_listener(Channel *c, fd_set *readset, fd_set *writeset)
1296 {
1297 Channel *nc;
1298 struct sockaddr_storage addr;
1299 int newsock;
1300 socklen_t addrlen;
1301 char buf[16384], *remote_ipaddr;
1302 int remote_port;
1303
1304 if (FD_ISSET(c->sock, readset)) {
1305 debug("X11 connection requested.");
1306 addrlen = sizeof(addr);
1307 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1308 if (c->single_connection) {
1309 debug2("single_connection: closing X11 listener.");
1310 channel_close_fd(&c->sock);
1311 chan_mark_dead(c);
1312 }
1313 if (newsock < 0) {
1314 error("accept: %.100s", strerror(errno));
1315 return;
1316 }
1317 set_nodelay(newsock);
1318 remote_ipaddr = get_peer_ipaddr(newsock);
1319 remote_port = get_peer_port(newsock);
1320 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1321 remote_ipaddr, remote_port);
1322
1323 nc = channel_new("accepted x11 socket",
1324 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1325 c->local_window_max, c->local_maxpacket, 0, buf, 1);
1326 if (compat20) {
1327 packet_start(SSH2_MSG_CHANNEL_OPEN);
1328 packet_put_cstring("x11");
1329 packet_put_int(nc->self);
1330 packet_put_int(nc->local_window_max);
1331 packet_put_int(nc->local_maxpacket);
1332 /* originator ipaddr and port */
1333 packet_put_cstring(remote_ipaddr);
1334 if (datafellows & SSH_BUG_X11FWD) {
1335 debug2("ssh2 x11 bug compat mode");
1336 } else {
1337 packet_put_int(remote_port);
1338 }
1339 packet_send();
1340 } else {
1341 packet_start(SSH_SMSG_X11_OPEN);
1342 packet_put_int(nc->self);
1343 if (packet_get_protocol_flags() &
1344 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1345 packet_put_cstring(buf);
1346 packet_send();
1347 }
1348 xfree(remote_ipaddr);
1349 }
1350 }
1351
1352 static void
1353 port_open_helper(Channel *c, char *rtype)
1354 {
1355 int direct;
1356 char buf[1024];
1357 char *remote_ipaddr = get_peer_ipaddr(c->sock);
1358 int remote_port = get_peer_port(c->sock);
1359
1360 direct = (strcmp(rtype, "direct-tcpip") == 0);
1361
1362 snprintf(buf, sizeof buf,
1363 "%s: listening port %d for %.100s port %d, "
1364 "connect from %.200s port %d",
1365 rtype, c->listening_port, c->path, c->host_port,
1366 remote_ipaddr, remote_port);
1367
1368 xfree(c->remote_name);
1369 c->remote_name = xstrdup(buf);
1370
1371 if (compat20) {
1372 packet_start(SSH2_MSG_CHANNEL_OPEN);
1373 packet_put_cstring(rtype);
1374 packet_put_int(c->self);
1375 packet_put_int(c->local_window_max);
1376 packet_put_int(c->local_maxpacket);
1377 if (direct) {
1378 /* target host, port */
1379 packet_put_cstring(c->path);
1380 packet_put_int(c->host_port);
1381 } else {
1382 /* listen address, port */
1383 packet_put_cstring(c->path);
1384 packet_put_int(c->listening_port);
1385 }
1386 /* originator host and port */
1387 packet_put_cstring(remote_ipaddr);
1388 packet_put_int((u_int)remote_port);
1389 packet_send();
1390 } else {
1391 packet_start(SSH_MSG_PORT_OPEN);
1392 packet_put_int(c->self);
1393 packet_put_cstring(c->path);
1394 packet_put_int(c->host_port);
1395 if (packet_get_protocol_flags() &
1396 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1397 packet_put_cstring(c->remote_name);
1398 packet_send();
1399 }
1400 xfree(remote_ipaddr);
1401 }
1402
1403 static void
1404 channel_set_reuseaddr(int fd)
1405 {
1406 int on = 1;
1407
1408 /*
1409 * Set socket options.
1410 * Allow local port reuse in TIME_WAIT.
1411 */
1412 if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1)
1413 error("setsockopt SO_REUSEADDR fd %d: %s", fd, strerror(errno));
1414 }
1415
1416 /*
1417 * This socket is listening for connections to a forwarded TCP/IP port.
1418 */
1419 /* ARGSUSED */
1420 static void
1421 channel_post_port_listener(Channel *c, fd_set *readset, fd_set *writeset)
1422 {
1423 Channel *nc;
1424 struct sockaddr_storage addr;
1425 int newsock, nextstate;
1426 socklen_t addrlen;
1427 char *rtype;
1428
1429 if (FD_ISSET(c->sock, readset)) {
1430 debug("Connection to port %d forwarding "
1431 "to %.100s port %d requested.",
1432 c->listening_port, c->path, c->host_port);
1433
1434 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1435 nextstate = SSH_CHANNEL_OPENING;
1436 rtype = "forwarded-tcpip";
1437 } else {
1438 if (c->host_port == 0) {
1439 nextstate = SSH_CHANNEL_DYNAMIC;
1440 rtype = "dynamic-tcpip";
1441 } else {
1442 nextstate = SSH_CHANNEL_OPENING;
1443 rtype = "direct-tcpip";
1444 }
1445 }
1446
1447 addrlen = sizeof(addr);
1448 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1449 if (newsock < 0) {
1450 error("accept: %.100s", strerror(errno));
1451 return;
1452 }
1453 set_nodelay(newsock);
1454 nc = channel_new(rtype, nextstate, newsock, newsock, -1,
1455 c->local_window_max, c->local_maxpacket, 0, rtype, 1);
1456 nc->listening_port = c->listening_port;
1457 nc->host_port = c->host_port;
1458 if (c->path != NULL)
1459 nc->path = xstrdup(c->path);
1460
1461 if (nextstate != SSH_CHANNEL_DYNAMIC)
1462 port_open_helper(nc, rtype);
1463 }
1464 }
1465
1466 /*
1467 * This is the authentication agent socket listening for connections from
1468 * clients.
1469 */
1470 /* ARGSUSED */
1471 static void
1472 channel_post_auth_listener(Channel *c, fd_set *readset, fd_set *writeset)
1473 {
1474 Channel *nc;
1475 int newsock;
1476 struct sockaddr_storage addr;
1477 socklen_t addrlen;
1478
1479 if (FD_ISSET(c->sock, readset)) {
1480 addrlen = sizeof(addr);
1481 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1482 if (newsock < 0) {
1483 error("accept from auth socket: %.100s", strerror(errno));
1484 return;
1485 }
1486 nc = channel_new("accepted auth socket",
1487 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1488 c->local_window_max, c->local_maxpacket,
1489 0, "accepted auth socket", 1);
1490 if (compat20) {
1491 packet_start(SSH2_MSG_CHANNEL_OPEN);
1492 packet_put_cstring("auth-agent@openssh.com");
1493 packet_put_int(nc->self);
1494 packet_put_int(c->local_window_max);
1495 packet_put_int(c->local_maxpacket);
1496 } else {
1497 packet_start(SSH_SMSG_AGENT_OPEN);
1498 packet_put_int(nc->self);
1499 }
1500 packet_send();
1501 }
1502 }
1503
1504 /* ARGSUSED */
1505 static void
1506 channel_post_connecting(Channel *c, fd_set *readset, fd_set *writeset)
1507 {
1508 int err = 0, sock;
1509 socklen_t sz = sizeof(err);
1510
1511 if (FD_ISSET(c->sock, writeset)) {
1512 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) {
1513 err = errno;
1514 error("getsockopt SO_ERROR failed");
1515 }
1516 if (err == 0) {
1517 debug("channel %d: connected to %s port %d",
1518 c->self, c->connect_ctx.host, c->connect_ctx.port);
1519 channel_connect_ctx_free(&c->connect_ctx);
1520 c->type = SSH_CHANNEL_OPEN;
1521 if (compat20) {
1522 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1523 packet_put_int(c->remote_id);
1524 packet_put_int(c->self);
1525 packet_put_int(c->local_window);
1526 packet_put_int(c->local_maxpacket);
1527 } else {
1528 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1529 packet_put_int(c->remote_id);
1530 packet_put_int(c->self);
1531 }
1532 } else {
1533 debug("channel %d: connection failed: %s",
1534 c->self, strerror(err));
1535 /* Try next address, if any */
1536 if ((sock = connect_next(&c->connect_ctx)) > 0) {
1537 close(c->sock);
1538 c->sock = c->rfd = c->wfd = sock;
1539 channel_max_fd = channel_find_maxfd();
1540 return;
1541 }
1542 /* Exhausted all addresses */
1543 error("connect_to %.100s port %d: failed.",
1544 c->connect_ctx.host, c->connect_ctx.port);
1545 channel_connect_ctx_free(&c->connect_ctx);
1546 if (compat20) {
1547 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1548 packet_put_int(c->remote_id);
1549 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1550 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1551 packet_put_cstring(strerror(err));
1552 packet_put_cstring("");
1553 }
1554 } else {
1555 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1556 packet_put_int(c->remote_id);
1557 }
1558 chan_mark_dead(c);
1559 }
1560 packet_send();
1561 }
1562 }
1563
1564 /* ARGSUSED */
1565 static int
1566 channel_handle_rfd(Channel *c, fd_set *readset, fd_set *writeset)
1567 {
1568 char buf[CHAN_RBUF];
1569 int len, force;
1570
1571 force = c->isatty && c->detach_close && c->istate != CHAN_INPUT_CLOSED;
1572 if (c->rfd != -1 && (force || FD_ISSET(c->rfd, readset))) {
1573 errno = 0;
1574 len = read(c->rfd, buf, sizeof(buf));
1575 if (len < 0 && (errno == EINTR ||
1576 ((errno == EAGAIN || errno == EWOULDBLOCK) && !force)))
1577 return 1;
1578 #ifndef PTY_ZEROREAD
1579 if (len <= 0) {
1580 #else
1581 if ((!c->isatty && len <= 0) ||
1582 (c->isatty && (len < 0 || (len == 0 && errno != 0)))) {
1583 #endif
1584 debug2("channel %d: read<=0 rfd %d len %d",
1585 c->self, c->rfd, len);
1586 if (c->type != SSH_CHANNEL_OPEN) {
1587 debug2("channel %d: not open", c->self);
1588 chan_mark_dead(c);
1589 return -1;
1590 } else if (compat13) {
1591 buffer_clear(&c->output);
1592 c->type = SSH_CHANNEL_INPUT_DRAINING;
1593 debug2("channel %d: input draining.", c->self);
1594 } else {
1595 chan_read_failed(c);
1596 }
1597 return -1;
1598 }
1599 if (c->input_filter != NULL) {
1600 if (c->input_filter(c, buf, len) == -1) {
1601 debug2("channel %d: filter stops", c->self);
1602 chan_read_failed(c);
1603 }
1604 } else if (c->datagram) {
1605 buffer_put_string(&c->input, buf, len);
1606 } else {
1607 buffer_append(&c->input, buf, len);
1608 }
1609 }
1610 return 1;
1611 }
1612
1613 /* ARGSUSED */
1614 static int
1615 channel_handle_wfd(Channel *c, fd_set *readset, fd_set *writeset)
1616 {
1617 struct termios tio;
1618 u_char *data = NULL, *buf;
1619 u_int dlen;
1620 int len;
1621
1622 /* Send buffered output data to the socket. */
1623 if (c->wfd != -1 &&
1624 FD_ISSET(c->wfd, writeset) &&
1625 buffer_len(&c->output) > 0) {
1626 if (c->output_filter != NULL) {
1627 if ((buf = c->output_filter(c, &data, &dlen)) == NULL) {
1628 debug2("channel %d: filter stops", c->self);
1629 if (c->type != SSH_CHANNEL_OPEN)
1630 chan_mark_dead(c);
1631 else
1632 chan_write_failed(c);
1633 return -1;
1634 }
1635 } else if (c->datagram) {
1636 buf = data = buffer_get_string(&c->output, &dlen);
1637 } else {
1638 buf = data = buffer_ptr(&c->output);
1639 dlen = buffer_len(&c->output);
1640 }
1641
1642 if (c->datagram) {
1643 /* ignore truncated writes, datagrams might get lost */
1644 c->local_consumed += dlen + 4;
1645 len = write(c->wfd, buf, dlen);
1646 xfree(data);
1647 if (len < 0 && (errno == EINTR || errno == EAGAIN ||
1648 errno == EWOULDBLOCK))
1649 return 1;
1650 if (len <= 0) {
1651 if (c->type != SSH_CHANNEL_OPEN)
1652 chan_mark_dead(c);
1653 else
1654 chan_write_failed(c);
1655 return -1;
1656 }
1657 return 1;
1658 }
1659 #ifdef _AIX
1660 /* XXX: Later AIX versions can't push as much data to tty */
1661 if (compat20 && c->wfd_isatty)
1662 dlen = MIN(dlen, 8*1024);
1663 #endif
1664
1665 len = write(c->wfd, buf, dlen);
1666 if (len < 0 &&
1667 (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK))
1668 return 1;
1669 if (len <= 0) {
1670 if (c->type != SSH_CHANNEL_OPEN) {
1671 debug2("channel %d: not open", c->self);
1672 chan_mark_dead(c);
1673 return -1;
1674 } else if (compat13) {
1675 buffer_clear(&c->output);
1676 debug2("channel %d: input draining.", c->self);
1677 c->type = SSH_CHANNEL_INPUT_DRAINING;
1678 } else {
1679 chan_write_failed(c);
1680 }
1681 return -1;
1682 }
1683 #ifndef BROKEN_TCGETATTR_ICANON
1684 if (compat20 && c->isatty && dlen >= 1 && buf[0] != '\r') {
1685 if (tcgetattr(c->wfd, &tio) == 0 &&
1686 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1687 /*
1688 * Simulate echo to reduce the impact of
1689 * traffic analysis. We need to match the
1690 * size of a SSH2_MSG_CHANNEL_DATA message
1691 * (4 byte channel id + buf)
1692 */
1693 packet_send_ignore(4 + len);
1694 packet_send();
1695 }
1696 }
1697 #endif
1698 buffer_consume(&c->output, len);
1699 if (compat20 && len > 0) {
1700 c->local_consumed += len;
1701 }
1702 }
1703 return 1;
1704 }
1705
1706 static int
1707 channel_handle_efd(Channel *c, fd_set *readset, fd_set *writeset)
1708 {
1709 char buf[CHAN_RBUF];
1710 int len;
1711
1712 /** XXX handle drain efd, too */
1713 if (c->efd != -1) {
1714 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1715 FD_ISSET(c->efd, writeset) &&
1716 buffer_len(&c->extended) > 0) {
1717 len = write(c->efd, buffer_ptr(&c->extended),
1718 buffer_len(&c->extended));
1719 debug2("channel %d: written %d to efd %d",
1720 c->self, len, c->efd);
1721 if (len < 0 && (errno == EINTR || errno == EAGAIN ||
1722 errno == EWOULDBLOCK))
1723 return 1;
1724 if (len <= 0) {
1725 debug2("channel %d: closing write-efd %d",
1726 c->self, c->efd);
1727 channel_close_fd(&c->efd);
1728 } else {
1729 buffer_consume(&c->extended, len);
1730 c->local_consumed += len;
1731 }
1732 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
1733 (c->detach_close || FD_ISSET(c->efd, readset))) {
1734 len = read(c->efd, buf, sizeof(buf));
1735 debug2("channel %d: read %d from efd %d",
1736 c->self, len, c->efd);
1737 if (len < 0 && (errno == EINTR || ((errno == EAGAIN ||
1738 errno == EWOULDBLOCK) && !c->detach_close)))
1739 return 1;
1740 if (len <= 0) {
1741 debug2("channel %d: closing read-efd %d",
1742 c->self, c->efd);
1743 channel_close_fd(&c->efd);
1744 } else {
1745 buffer_append(&c->extended, buf, len);
1746 }
1747 }
1748 }
1749 return 1;
1750 }
1751
1752 /* ARGSUSED */
1753 static int
1754 channel_handle_ctl(Channel *c, fd_set *readset, fd_set *writeset)
1755 {
1756 char buf[16];
1757 int len;
1758
1759 /* Monitor control fd to detect if the slave client exits */
1760 if (c->ctl_fd != -1 && FD_ISSET(c->ctl_fd, readset)) {
1761 len = read(c->ctl_fd, buf, sizeof(buf));
1762 if (len < 0 &&
1763 (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK))
1764 return 1;
1765 if (len <= 0) {
1766 debug2("channel %d: ctl read<=0", c->self);
1767 if (c->type != SSH_CHANNEL_OPEN) {
1768 debug2("channel %d: not open", c->self);
1769 chan_mark_dead(c);
1770 return -1;
1771 } else {
1772 chan_read_failed(c);
1773 chan_write_failed(c);
1774 }
1775 return -1;
1776 } else
1777 fatal("%s: unexpected data on ctl fd", __func__);
1778 }
1779 return 1;
1780 }
1781
1782 static int
1783 channel_check_window(Channel *c)
1784 {
1785 if (c->type == SSH_CHANNEL_OPEN &&
1786 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1787 ((c->local_window_max - c->local_window >
1788 c->local_maxpacket*3) ||
1789 c->local_window < c->local_window_max/2) &&
1790 c->local_consumed > 0) {
1791 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1792 packet_put_int(c->remote_id);
1793 packet_put_int(c->local_consumed);
1794 packet_send();
1795 debug2("channel %d: window %d sent adjust %d",
1796 c->self, c->local_window,
1797 c->local_consumed);
1798 c->local_window += c->local_consumed;
1799 c->local_consumed = 0;
1800 }
1801 return 1;
1802 }
1803
1804 static void
1805 channel_post_open(Channel *c, fd_set *readset, fd_set *writeset)
1806 {
1807 channel_handle_rfd(c, readset, writeset);
1808 channel_handle_wfd(c, readset, writeset);
1809 if (!compat20)
1810 return;
1811 channel_handle_efd(c, readset, writeset);
1812 channel_handle_ctl(c, readset, writeset);
1813 channel_check_window(c);
1814 }
1815
1816 /* ARGSUSED */
1817 static void
1818 channel_post_output_drain_13(Channel *c, fd_set *readset, fd_set *writeset)
1819 {
1820 int len;
1821
1822 /* Send buffered output data to the socket. */
1823 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1824 len = write(c->sock, buffer_ptr(&c->output),
1825 buffer_len(&c->output));
1826 if (len <= 0)
1827 buffer_clear(&c->output);
1828 else
1829 buffer_consume(&c->output, len);
1830 }
1831 }
1832
1833 static void
1834 channel_handler_init_20(void)
1835 {
1836 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1837 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1838 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1839 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
1840 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1841 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1842 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1843 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1844
1845 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1846 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1847 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
1848 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1849 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1850 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1851 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1852 }
1853
1854 static void
1855 channel_handler_init_13(void)
1856 {
1857 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
1858 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
1859 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1860 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1861 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1862 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
1863 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1864 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1865 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1866
1867 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1868 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1869 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1870 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1871 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
1872 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1873 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1874 }
1875
1876 static void
1877 channel_handler_init_15(void)
1878 {
1879 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1880 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1881 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1882 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1883 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1884 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1885 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1886
1887 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1888 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1889 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1890 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1891 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1892 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1893 }
1894
1895 static void
1896 channel_handler_init(void)
1897 {
1898 int i;
1899
1900 for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
1901 channel_pre[i] = NULL;
1902 channel_post[i] = NULL;
1903 }
1904 if (compat20)
1905 channel_handler_init_20();
1906 else if (compat13)
1907 channel_handler_init_13();
1908 else
1909 channel_handler_init_15();
1910 }
1911
1912 /* gc dead channels */
1913 static void
1914 channel_garbage_collect(Channel *c)
1915 {
1916 if (c == NULL)
1917 return;
1918 if (c->detach_user != NULL) {
1919 if (!chan_is_dead(c, c->detach_close))
1920 return;
1921 debug2("channel %d: gc: notify user", c->self);
1922 c->detach_user(c->self, NULL);
1923 /* if we still have a callback */
1924 if (c->detach_user != NULL)
1925 return;
1926 debug2("channel %d: gc: user detached", c->self);
1927 }
1928 if (!chan_is_dead(c, 1))
1929 return;
1930 debug2("channel %d: garbage collecting", c->self);
1931 channel_free(c);
1932 }
1933
1934 static void
1935 channel_handler(chan_fn *ftab[], fd_set *readset, fd_set *writeset)
1936 {
1937 static int did_init = 0;
1938 u_int i, oalloc;
1939 Channel *c;
1940
1941 if (!did_init) {
1942 channel_handler_init();
1943 did_init = 1;
1944 }
1945 for (i = 0, oalloc = channels_alloc; i < oalloc; i++) {
1946 c = channels[i];
1947 if (c == NULL)
1948 continue;
1949 if (c->delayed) {
1950 if (ftab == channel_pre)
1951 c->delayed = 0;
1952 else
1953 continue;
1954 }
1955 if (ftab[c->type] != NULL)
1956 (*ftab[c->type])(c, readset, writeset);
1957 channel_garbage_collect(c);
1958 }
1959 }
1960
1961 /*
1962 * Allocate/update select bitmasks and add any bits relevant to channels in
1963 * select bitmasks.
1964 */
1965 void
1966 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
1967 u_int *nallocp, int rekeying)
1968 {
1969 u_int n, sz, nfdset;
1970
1971 n = MAX(*maxfdp, channel_max_fd);
1972
1973 nfdset = howmany(n+1, NFDBITS);
1974 /* Explicitly test here, because xrealloc isn't always called */
1975 if (nfdset && SIZE_T_MAX / nfdset < sizeof(fd_mask))
1976 fatal("channel_prepare_select: max_fd (%d) is too large", n);
1977 sz = nfdset * sizeof(fd_mask);
1978
1979 /* perhaps check sz < nalloc/2 and shrink? */
1980 if (*readsetp == NULL || sz > *nallocp) {
1981 *readsetp = xrealloc(*readsetp, nfdset, sizeof(fd_mask));
1982 *writesetp = xrealloc(*writesetp, nfdset, sizeof(fd_mask));
1983 *nallocp = sz;
1984 }
1985 *maxfdp = n;
1986 memset(*readsetp, 0, sz);
1987 memset(*writesetp, 0, sz);
1988
1989 if (!rekeying)
1990 channel_handler(channel_pre, *readsetp, *writesetp);
1991 }
1992
1993 /*
1994 * After select, perform any appropriate operations for channels which have
1995 * events pending.
1996 */
1997 void
1998 channel_after_select(fd_set *readset, fd_set *writeset)
1999 {
2000 channel_handler(channel_post, readset, writeset);
2001 }
2002
2003
2004 /* If there is data to send to the connection, enqueue some of it now. */
2005 void
2006 channel_output_poll(void)
2007 {
2008 Channel *c;
2009 u_int i, len;
2010
2011 for (i = 0; i < channels_alloc; i++) {
2012 c = channels[i];
2013 if (c == NULL)
2014 continue;
2015
2016 /*
2017 * We are only interested in channels that can have buffered
2018 * incoming data.
2019 */
2020 if (compat13) {
2021 if (c->type != SSH_CHANNEL_OPEN &&
2022 c->type != SSH_CHANNEL_INPUT_DRAINING)
2023 continue;
2024 } else {
2025 if (c->type != SSH_CHANNEL_OPEN)
2026 continue;
2027 }
2028 if (compat20 &&
2029 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
2030 /* XXX is this true? */
2031 debug3("channel %d: will not send data after close", c->self);
2032 continue;
2033 }
2034
2035 /* Get the amount of buffered data for this channel. */
2036 if ((c->istate == CHAN_INPUT_OPEN ||
2037 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
2038 (len = buffer_len(&c->input)) > 0) {
2039 if (c->datagram) {
2040 if (len > 0) {
2041 u_char *data;
2042 u_int dlen;
2043
2044 data = buffer_get_string(&c->input,
2045 &dlen);
2046 packet_start(SSH2_MSG_CHANNEL_DATA);
2047 packet_put_int(c->remote_id);
2048 packet_put_string(data, dlen);
2049 packet_send();
2050 c->remote_window -= dlen + 4;
2051 xfree(data);
2052 }
2053 continue;
2054 }
2055 /*
2056 * Send some data for the other side over the secure
2057 * connection.
2058 */
2059 if (compat20) {
2060 if (len > c->remote_window)
2061 len = c->remote_window;
2062 if (len > c->remote_maxpacket)
2063 len = c->remote_maxpacket;
2064 } else {
2065 if (packet_is_interactive()) {
2066 if (len > 1024)
2067 len = 512;
2068 } else {
2069 /* Keep the packets at reasonable size. */
2070 if (len > packet_get_maxsize()/2)
2071 len = packet_get_maxsize()/2;
2072 }
2073 }
2074 if (len > 0) {
2075 packet_start(compat20 ?
2076 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
2077 packet_put_int(c->remote_id);
2078 packet_put_string(buffer_ptr(&c->input), len);
2079 packet_send();
2080 buffer_consume(&c->input, len);
2081 c->remote_window -= len;
2082 }
2083 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
2084 if (compat13)
2085 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
2086 /*
2087 * input-buffer is empty and read-socket shutdown:
2088 * tell peer, that we will not send more data: send IEOF.
2089 * hack for extended data: delay EOF if EFD still in use.
2090 */
2091 if (CHANNEL_EFD_INPUT_ACTIVE(c))
2092 debug2("channel %d: ibuf_empty delayed efd %d/(%d)",
2093 c->self, c->efd, buffer_len(&c->extended));
2094 else
2095 chan_ibuf_empty(c);
2096 }
2097 /* Send extended data, i.e. stderr */
2098 if (compat20 &&
2099 !(c->flags & CHAN_EOF_SENT) &&
2100 c->remote_window > 0 &&
2101 (len = buffer_len(&c->extended)) > 0 &&
2102 c->extended_usage == CHAN_EXTENDED_READ) {
2103 debug2("channel %d: rwin %u elen %u euse %d",
2104 c->self, c->remote_window, buffer_len(&c->extended),
2105 c->extended_usage);
2106 if (len > c->remote_window)
2107 len = c->remote_window;
2108 if (len > c->remote_maxpacket)
2109 len = c->remote_maxpacket;
2110 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
2111 packet_put_int(c->remote_id);
2112 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
2113 packet_put_string(buffer_ptr(&c->extended), len);
2114 packet_send();
2115 buffer_consume(&c->extended, len);
2116 c->remote_window -= len;
2117 debug2("channel %d: sent ext data %d", c->self, len);
2118 }
2119 }
2120 }
2121
2122
2123 /* -- protocol input */
2124
2125 /* ARGSUSED */
2126 void
2127 channel_input_data(int type, u_int32_t seq, void *ctxt)
2128 {
2129 int id;
2130 char *data;
2131 u_int data_len;
2132 Channel *c;
2133
2134 /* Get the channel number and verify it. */
2135 id = packet_get_int();
2136 c = channel_lookup(id);
2137 if (c == NULL)
2138 packet_disconnect("Received data for nonexistent channel %d.", id);
2139
2140 /* Ignore any data for non-open channels (might happen on close) */
2141 if (c->type != SSH_CHANNEL_OPEN &&
2142 c->type != SSH_CHANNEL_X11_OPEN)
2143 return;
2144
2145 /* Get the data. */
2146 data = packet_get_string_ptr(&data_len);
2147
2148 /*
2149 * Ignore data for protocol > 1.3 if output end is no longer open.
2150 * For protocol 2 the sending side is reducing its window as it sends
2151 * data, so we must 'fake' consumption of the data in order to ensure
2152 * that window updates are sent back. Otherwise the connection might
2153 * deadlock.
2154 */
2155 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) {
2156 if (compat20) {
2157 c->local_window -= data_len;
2158 c->local_consumed += data_len;
2159 }
2160 return;
2161 }
2162
2163 if (compat20) {
2164 if (data_len > c->local_maxpacket) {
2165 logit("channel %d: rcvd big packet %d, maxpack %d",
2166 c->self, data_len, c->local_maxpacket);
2167 }
2168 if (data_len > c->local_window) {
2169 logit("channel %d: rcvd too much data %d, win %d",
2170 c->self, data_len, c->local_window);
2171 return;
2172 }
2173 c->local_window -= data_len;
2174 }
2175 if (c->datagram)
2176 buffer_put_string(&c->output, data, data_len);
2177 else
2178 buffer_append(&c->output, data, data_len);
2179 packet_check_eom();
2180 }
2181
2182 /* ARGSUSED */
2183 void
2184 channel_input_extended_data(int type, u_int32_t seq, void *ctxt)
2185 {
2186 int id;
2187 char *data;
2188 u_int data_len, tcode;
2189 Channel *c;
2190
2191 /* Get the channel number and verify it. */
2192 id = packet_get_int();
2193 c = channel_lookup(id);
2194
2195 if (c == NULL)
2196 packet_disconnect("Received extended_data for bad channel %d.", id);
2197 if (c->type != SSH_CHANNEL_OPEN) {
2198 logit("channel %d: ext data for non open", id);
2199 return;
2200 }
2201 if (c->flags & CHAN_EOF_RCVD) {
2202 if (datafellows & SSH_BUG_EXTEOF)
2203 debug("channel %d: accepting ext data after eof", id);
2204 else
2205 packet_disconnect("Received extended_data after EOF "
2206 "on channel %d.", id);
2207 }
2208 tcode = packet_get_int();
2209 if (c->efd == -1 ||
2210 c->extended_usage != CHAN_EXTENDED_WRITE ||
2211 tcode != SSH2_EXTENDED_DATA_STDERR) {
2212 logit("channel %d: bad ext data", c->self);
2213 return;
2214 }
2215 data = packet_get_string(&data_len);
2216 packet_check_eom();
2217 if (data_len > c->local_window) {
2218 logit("channel %d: rcvd too much extended_data %d, win %d",
2219 c->self, data_len, c->local_window);
2220 xfree(data);
2221 return;
2222 }
2223 debug2("channel %d: rcvd ext data %d", c->self, data_len);
2224 c->local_window -= data_len;
2225 buffer_append(&c->extended, data, data_len);
2226 xfree(data);
2227 }
2228
2229 /* ARGSUSED */
2230 void
2231 channel_input_ieof(int type, u_int32_t seq, void *ctxt)
2232 {
2233 int id;
2234 Channel *c;
2235
2236 id = packet_get_int();
2237 packet_check_eom();
2238 c = channel_lookup(id);
2239 if (c == NULL)
2240 packet_disconnect("Received ieof for nonexistent channel %d.", id);
2241 chan_rcvd_ieof(c);
2242
2243 /* XXX force input close */
2244 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) {
2245 debug("channel %d: FORCE input drain", c->self);
2246 c->istate = CHAN_INPUT_WAIT_DRAIN;
2247 if (buffer_len(&c->input) == 0)
2248 chan_ibuf_empty(c);
2249 }
2250
2251 }
2252
2253 /* ARGSUSED */
2254 void
2255 channel_input_close(int type, u_int32_t seq, void *ctxt)
2256 {
2257 int id;
2258 Channel *c;
2259
2260 id = packet_get_int();
2261 packet_check_eom();
2262 c = channel_lookup(id);
2263 if (c == NULL)
2264 packet_disconnect("Received close for nonexistent channel %d.", id);
2265
2266 /*
2267 * Send a confirmation that we have closed the channel and no more
2268 * data is coming for it.
2269 */
2270 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
2271 packet_put_int(c->remote_id);
2272 packet_send();
2273
2274 /*
2275 * If the channel is in closed state, we have sent a close request,
2276 * and the other side will eventually respond with a confirmation.
2277 * Thus, we cannot free the channel here, because then there would be
2278 * no-one to receive the confirmation. The channel gets freed when
2279 * the confirmation arrives.
2280 */
2281 if (c->type != SSH_CHANNEL_CLOSED) {
2282 /*
2283 * Not a closed channel - mark it as draining, which will
2284 * cause it to be freed later.
2285 */
2286 buffer_clear(&c->input);
2287 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
2288 }
2289 }
2290
2291 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
2292 /* ARGSUSED */
2293 void
2294 channel_input_oclose(int type, u_int32_t seq, void *ctxt)
2295 {
2296 int id = packet_get_int();
2297 Channel *c = channel_lookup(id);
2298
2299 packet_check_eom();
2300 if (c == NULL)
2301 packet_disconnect("Received oclose for nonexistent channel %d.", id);
2302 chan_rcvd_oclose(c);
2303 }
2304
2305 /* ARGSUSED */
2306 void
2307 channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt)
2308 {
2309 int id = packet_get_int();
2310 Channel *c = channel_lookup(id);
2311
2312 packet_check_eom();
2313 if (c == NULL)
2314 packet_disconnect("Received close confirmation for "
2315 "out-of-range channel %d.", id);
2316 if (c->type != SSH_CHANNEL_CLOSED)
2317 packet_disconnect("Received close confirmation for "
2318 "non-closed channel %d (type %d).", id, c->type);
2319 channel_free(c);
2320 }
2321
2322 /* ARGSUSED */
2323 void
2324 channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt)
2325 {
2326 int id, remote_id;
2327 Channel *c;
2328
2329 id = packet_get_int();
2330 c = channel_lookup(id);
2331
2332 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2333 packet_disconnect("Received open confirmation for "
2334 "non-opening channel %d.", id);
2335 remote_id = packet_get_int();
2336 /* Record the remote channel number and mark that the channel is now open. */
2337 c->remote_id = remote_id;
2338 c->type = SSH_CHANNEL_OPEN;
2339
2340 if (compat20) {
2341 c->remote_window = packet_get_int();
2342 c->remote_maxpacket = packet_get_int();
2343 if (c->open_confirm) {
2344 debug2("callback start");
2345 c->open_confirm(c->self, c->open_confirm_ctx);
2346 debug2("callback done");
2347 }
2348 debug2("channel %d: open confirm rwindow %u rmax %u", c->self,
2349 c->remote_window, c->remote_maxpacket);
2350 }
2351 packet_check_eom();
2352 }
2353
2354 static char *
2355 reason2txt(int reason)
2356 {
2357 switch (reason) {
2358 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
2359 return "administratively prohibited";
2360 case SSH2_OPEN_CONNECT_FAILED:
2361 return "connect failed";
2362 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
2363 return "unknown channel type";
2364 case SSH2_OPEN_RESOURCE_SHORTAGE:
2365 return "resource shortage";
2366 }
2367 return "unknown reason";
2368 }
2369
2370 /* ARGSUSED */
2371 void
2372 channel_input_open_failure(int type, u_int32_t seq, void *ctxt)
2373 {
2374 int id, reason;
2375 char *msg = NULL, *lang = NULL;
2376 Channel *c;
2377
2378 id = packet_get_int();
2379 c = channel_lookup(id);
2380
2381 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2382 packet_disconnect("Received open failure for "
2383 "non-opening channel %d.", id);
2384 if (compat20) {
2385 reason = packet_get_int();
2386 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
2387 msg = packet_get_string(NULL);
2388 lang = packet_get_string(NULL);
2389 }
2390 logit("channel %d: open failed: %s%s%s", id,
2391 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
2392 if (msg != NULL)
2393 xfree(msg);
2394 if (lang != NULL)
2395 xfree(lang);
2396 }
2397 packet_check_eom();
2398 /* Schedule the channel for cleanup/deletion. */
2399 chan_mark_dead(c);
2400 }
2401
2402 /* ARGSUSED */
2403 void
2404 channel_input_window_adjust(int type, u_int32_t seq, void *ctxt)
2405 {
2406 Channel *c;
2407 int id;
2408 u_int adjust;
2409
2410 if (!compat20)
2411 return;
2412
2413 /* Get the channel number and verify it. */
2414 id = packet_get_int();
2415 c = channel_lookup(id);
2416
2417 if (c == NULL) {
2418 logit("Received window adjust for non-open channel %d.", id);
2419 return;
2420 }
2421 adjust = packet_get_int();
2422 packet_check_eom();
2423 debug2("channel %d: rcvd adjust %u", id, adjust);
2424 c->remote_window += adjust;
2425 }
2426
2427 /* ARGSUSED */
2428 void
2429 channel_input_port_open(int type, u_int32_t seq, void *ctxt)
2430 {
2431 Channel *c = NULL;
2432 u_short host_port;
2433 char *host, *originator_string;
2434 int remote_id;
2435
2436 remote_id = packet_get_int();
2437 host = packet_get_string(NULL);
2438 host_port = packet_get_int();
2439
2440 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2441 originator_string = packet_get_string(NULL);
2442 } else {
2443 originator_string = xstrdup("unknown (remote did not supply name)");
2444 }
2445 packet_check_eom();
2446 c = channel_connect_to(host, host_port,
2447 "connected socket", originator_string);
2448 xfree(originator_string);
2449 xfree(host);
2450 if (c == NULL) {
2451 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2452 packet_put_int(remote_id);
2453 packet_send();
2454 } else
2455 c->remote_id = remote_id;
2456 }
2457
2458 /* ARGSUSED */
2459 void
2460 channel_input_status_confirm(int type, u_int32_t seq, void *ctxt)
2461 {
2462 Channel *c;
2463 struct channel_confirm *cc;
2464 int id;
2465
2466 /* Reset keepalive timeout */
2467 packet_set_alive_timeouts(0);
2468
2469 id = packet_get_int();
2470 packet_check_eom();
2471
2472 debug2("channel_input_status_confirm: type %d id %d", type, id);
2473
2474 if ((c = channel_lookup(id)) == NULL) {
2475 logit("channel_input_status_confirm: %d: unknown", id);
2476 return;
2477 }
2478 ;
2479 if ((cc = TAILQ_FIRST(&c->status_confirms)) == NULL)
2480 return;
2481 cc->cb(type, c, cc->ctx);
2482 TAILQ_REMOVE(&c->status_confirms, cc, entry);
2483 bzero(cc, sizeof(*cc));
2484 xfree(cc);
2485 }
2486
2487 /* -- tcp forwarding */
2488
2489 void
2490 channel_set_af(int af)
2491 {
2492 IPv4or6 = af;
2493 }
2494
2495 static int
2496 channel_setup_fwd_listener(int type, const char *listen_addr,
2497 u_short listen_port, int *allocated_listen_port,
2498 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2499 {
2500 Channel *c;
2501 int sock, r, success = 0, wildcard = 0, is_client;
2502 struct addrinfo hints, *ai, *aitop;
2503 const char *host, *addr;
2504 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2505 in_port_t *lport_p;
2506
2507 host = (type == SSH_CHANNEL_RPORT_LISTENER) ?
2508 listen_addr : host_to_connect;
2509 is_client = (type == SSH_CHANNEL_PORT_LISTENER);
2510
2511 if (host == NULL) {
2512 error("No forward host name.");
2513 return 0;
2514 }
2515 if (strlen(host) >= NI_MAXHOST) {
2516 error("Forward host name too long.");
2517 return 0;
2518 }
2519
2520 /*
2521 * Determine whether or not a port forward listens to loopback,
2522 * specified address or wildcard. On the client, a specified bind
2523 * address will always override gateway_ports. On the server, a
2524 * gateway_ports of 1 (``yes'') will override the client's
2525 * specification and force a wildcard bind, whereas a value of 2
2526 * (``clientspecified'') will bind to whatever address the client
2527 * asked for.
2528 *
2529 * Special-case listen_addrs are:
2530 *
2531 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR
2532 * "" (empty string), "*" -> wildcard v4/v6
2533 * "localhost" -> loopback v4/v6
2534 */
2535 addr = NULL;
2536 if (listen_addr == NULL) {
2537 /* No address specified: default to gateway_ports setting */
2538 if (gateway_ports)
2539 wildcard = 1;
2540 } else if (gateway_ports || is_client) {
2541 if (((datafellows & SSH_OLD_FORWARD_ADDR) &&
2542 strcmp(listen_addr, "0.0.0.0") == 0 && is_client == 0) ||
2543 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 ||
2544 (!is_client && gateway_ports == 1))
2545 wildcard = 1;
2546 else if (strcmp(listen_addr, "localhost") != 0)
2547 addr = listen_addr;
2548 }
2549
2550 debug3("channel_setup_fwd_listener: type %d wildcard %d addr %s",
2551 type, wildcard, (addr == NULL) ? "NULL" : addr);
2552
2553 /*
2554 * getaddrinfo returns a loopback address if the hostname is
2555 * set to NULL and hints.ai_flags is not AI_PASSIVE
2556 */
2557 memset(&hints, 0, sizeof(hints));
2558 hints.ai_family = IPv4or6;
2559 hints.ai_flags = wildcard ? AI_PASSIVE : 0;
2560 hints.ai_socktype = SOCK_STREAM;
2561 snprintf(strport, sizeof strport, "%d", listen_port);
2562 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) {
2563 if (addr == NULL) {
2564 /* This really shouldn't happen */
2565 packet_disconnect("getaddrinfo: fatal error: %s",
2566 ssh_gai_strerror(r));
2567 } else {
2568 error("channel_setup_fwd_listener: "
2569 "getaddrinfo(%.64s): %s", addr,
2570 ssh_gai_strerror(r));
2571 }
2572 return 0;
2573 }
2574 if (allocated_listen_port != NULL)
2575 *allocated_listen_port = 0;
2576 for (ai = aitop; ai; ai = ai->ai_next) {
2577 switch (ai->ai_family) {
2578 case AF_INET:
2579 lport_p = &((struct sockaddr_in *)ai->ai_addr)->
2580 sin_port;
2581 break;
2582 case AF_INET6:
2583 lport_p = &((struct sockaddr_in6 *)ai->ai_addr)->
2584 sin6_port;
2585 break;
2586 default:
2587 continue;
2588 }
2589 /*
2590 * If allocating a port for -R forwards, then use the
2591 * same port for all address families.
2592 */
2593 if (type == SSH_CHANNEL_RPORT_LISTENER && listen_port == 0 &&
2594 allocated_listen_port != NULL && *allocated_listen_port > 0)
2595 *lport_p = htons(*allocated_listen_port);
2596
2597 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2598 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2599 error("channel_setup_fwd_listener: getnameinfo failed");
2600 continue;
2601 }
2602 /* Create a port to listen for the host. */
2603 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2604 if (sock < 0) {
2605 /* this is no error since kernel may not support ipv6 */
2606 verbose("socket: %.100s", strerror(errno));
2607 continue;
2608 }
2609
2610 channel_set_reuseaddr(sock);
2611 if (ai->ai_family == AF_INET6)
2612 sock_set_v6only(sock);
2613
2614 debug("Local forwarding listening on %s port %s.",
2615 ntop, strport);
2616
2617 /* Bind the socket to the address. */
2618 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2619 /* address can be in use ipv6 address is already bound */
2620 if (!ai->ai_next)
2621 error("bind: %.100s", strerror(errno));
2622 else
2623 verbose("bind: %.100s", strerror(errno));
2624
2625 close(sock);
2626 continue;
2627 }
2628 /* Start listening for connections on the socket. */
2629 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2630 error("listen: %.100s", strerror(errno));
2631 close(sock);
2632 continue;
2633 }
2634
2635 /*
2636 * listen_port == 0 requests a dynamically allocated port -
2637 * record what we got.
2638 */
2639 if (type == SSH_CHANNEL_RPORT_LISTENER && listen_port == 0 &&
2640 allocated_listen_port != NULL &&
2641 *allocated_listen_port == 0) {
2642 *allocated_listen_port = get_sock_port(sock, 1);
2643 debug("Allocated listen port %d",
2644 *allocated_listen_port);
2645 }
2646
2647 /* Allocate a channel number for the socket. */
2648 c = channel_new("port listener", type, sock, sock, -1,
2649 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2650 0, "port listener", 1);
2651 c->path = xstrdup(host);
2652 c->host_port = port_to_connect;
2653 c->listening_port = listen_port;
2654 success = 1;
2655 }
2656 if (success == 0)
2657 error("channel_setup_fwd_listener: cannot listen to port: %d",
2658 listen_port);
2659 freeaddrinfo(aitop);
2660 return success;
2661 }
2662
2663 int
2664 channel_cancel_rport_listener(const char *host, u_short port)
2665 {
2666 u_int i;
2667 int found = 0;
2668
2669 for (i = 0; i < channels_alloc; i++) {
2670 Channel *c = channels[i];
2671
2672 if (c != NULL && c->type == SSH_CHANNEL_RPORT_LISTENER &&
2673 strcmp(c->path, host) == 0 && c->listening_port == port) {
2674 debug2("%s: close channel %d", __func__, i);
2675 channel_free(c);
2676 found = 1;
2677 }
2678 }
2679
2680 return (found);
2681 }
2682
2683 /* protocol local port fwd, used by ssh (and sshd in v1) */
2684 int
2685 channel_setup_local_fwd_listener(const char *listen_host, u_short listen_port,
2686 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2687 {
2688 return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER,
2689 listen_host, listen_port, NULL, host_to_connect, port_to_connect,
2690 gateway_ports);
2691 }
2692
2693 /* protocol v2 remote port fwd, used by sshd */
2694 int
2695 channel_setup_remote_fwd_listener(const char *listen_address,
2696 u_short listen_port, int *allocated_listen_port, int gateway_ports)
2697 {
2698 return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER,
2699 listen_address, listen_port, allocated_listen_port,
2700 NULL, 0, gateway_ports);
2701 }
2702
2703 /*
2704 * Initiate forwarding of connections to port "port" on remote host through
2705 * the secure channel to host:port from local side.
2706 */
2707
2708 int
2709 channel_request_remote_forwarding(const char *listen_host, u_short listen_port,
2710 const char *host_to_connect, u_short port_to_connect)
2711 {
2712 int type, success = 0;
2713
2714 /* Record locally that connection to this host/port is permitted. */
2715 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2716 fatal("channel_request_remote_forwarding: too many forwards");
2717
2718 /* Send the forward request to the remote side. */
2719 if (compat20) {
2720 const char *address_to_bind;
2721 if (listen_host == NULL) {
2722 if (datafellows & SSH_BUG_RFWD_ADDR)
2723 address_to_bind = "127.0.0.1";
2724 else
2725 address_to_bind = "localhost";
2726 } else if (*listen_host == '\0' ||
2727 strcmp(listen_host, "*") == 0) {
2728 if (datafellows & SSH_BUG_RFWD_ADDR)
2729 address_to_bind = "0.0.0.0";
2730 else
2731 address_to_bind = "";
2732 } else
2733 address_to_bind = listen_host;
2734
2735 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2736 packet_put_cstring("tcpip-forward");
2737 packet_put_char(1); /* boolean: want reply */
2738 packet_put_cstring(address_to_bind);
2739 packet_put_int(listen_port);
2740 packet_send();
2741 packet_write_wait();
2742 /* Assume that server accepts the request */
2743 success = 1;
2744 } else {
2745 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2746 packet_put_int(listen_port);
2747 packet_put_cstring(host_to_connect);
2748 packet_put_int(port_to_connect);
2749 packet_send();
2750 packet_write_wait();
2751
2752 /* Wait for response from the remote side. */
2753 type = packet_read();
2754 switch (type) {
2755 case SSH_SMSG_SUCCESS:
2756 success = 1;
2757 break;
2758 case SSH_SMSG_FAILURE:
2759 break;
2760 default:
2761 /* Unknown packet */
2762 packet_disconnect("Protocol error for port forward request:"
2763 "received packet type %d.", type);
2764 }
2765 }
2766 if (success) {
2767 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2768 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2769 permitted_opens[num_permitted_opens].listen_port = listen_port;
2770 num_permitted_opens++;
2771 }
2772 return (success ? 0 : -1);
2773 }
2774
2775 /*
2776 * Request cancellation of remote forwarding of connection host:port from
2777 * local side.
2778 */
2779 void
2780 channel_request_rforward_cancel(const char *host, u_short port)
2781 {
2782 int i;
2783
2784 if (!compat20)
2785 return;
2786
2787 for (i = 0; i < num_permitted_opens; i++) {
2788 if (permitted_opens[i].host_to_connect != NULL &&
2789 permitted_opens[i].listen_port == port)
2790 break;
2791 }
2792 if (i >= num_permitted_opens) {
2793 debug("%s: requested forward not found", __func__);
2794 return;
2795 }
2796 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2797 packet_put_cstring("cancel-tcpip-forward");
2798 packet_put_char(0);
2799 packet_put_cstring(host == NULL ? "" : host);
2800 packet_put_int(port);
2801 packet_send();
2802
2803 permitted_opens[i].listen_port = 0;
2804 permitted_opens[i].port_to_connect = 0;
2805 xfree(permitted_opens[i].host_to_connect);
2806 permitted_opens[i].host_to_connect = NULL;
2807 }
2808
2809 /*
2810 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
2811 * listening for the port, and sends back a success reply (or disconnect
2812 * message if there was an error).
2813 */
2814 int
2815 channel_input_port_forward_request(int is_root, int gateway_ports)
2816 {
2817 u_short port, host_port;
2818 int success = 0;
2819 char *hostname;
2820
2821 /* Get arguments from the packet. */
2822 port = packet_get_int();
2823 hostname = packet_get_string(NULL);
2824 host_port = packet_get_int();
2825
2826 #ifndef HAVE_CYGWIN
2827 /*
2828 * Check that an unprivileged user is not trying to forward a
2829 * privileged port.
2830 */
2831 if (port < IPPORT_RESERVED && !is_root)
2832 packet_disconnect(
2833 "Requested forwarding of port %d but user is not root.",
2834 port);
2835 if (host_port == 0)
2836 packet_disconnect("Dynamic forwarding denied.");
2837 #endif
2838
2839 /* Initiate forwarding */
2840 success = channel_setup_local_fwd_listener(NULL, port, hostname,
2841 host_port, gateway_ports);
2842
2843 /* Free the argument string. */
2844 xfree(hostname);
2845
2846 return (success ? 0 : -1);
2847 }
2848
2849 /*
2850 * Permits opening to any host/port if permitted_opens[] is empty. This is
2851 * usually called by the server, because the user could connect to any port
2852 * anyway, and the server has no way to know but to trust the client anyway.
2853 */
2854 void
2855 channel_permit_all_opens(void)
2856 {
2857 if (num_permitted_opens == 0)
2858 all_opens_permitted = 1;
2859 }
2860
2861 void
2862 channel_add_permitted_opens(char *host, int port)
2863 {
2864 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2865 fatal("channel_add_permitted_opens: too many forwards");
2866 debug("allow port forwarding to host %s port %d", host, port);
2867
2868 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
2869 permitted_opens[num_permitted_opens].port_to_connect = port;
2870 num_permitted_opens++;
2871
2872 all_opens_permitted = 0;
2873 }
2874
2875 int
2876 channel_add_adm_permitted_opens(char *host, int port)
2877 {
2878 if (num_adm_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2879 fatal("channel_add_adm_permitted_opens: too many forwards");
2880 debug("config allows port forwarding to host %s port %d", host, port);
2881
2882 permitted_adm_opens[num_adm_permitted_opens].host_to_connect
2883 = xstrdup(host);
2884 permitted_adm_opens[num_adm_permitted_opens].port_to_connect = port;
2885 return ++num_adm_permitted_opens;
2886 }
2887
2888 void
2889 channel_clear_permitted_opens(void)
2890 {
2891 int i;
2892
2893 for (i = 0; i < num_permitted_opens; i++)
2894 if (permitted_opens[i].host_to_connect != NULL)
2895 xfree(permitted_opens[i].host_to_connect);
2896 num_permitted_opens = 0;
2897 }
2898
2899 void
2900 channel_clear_adm_permitted_opens(void)
2901 {
2902 int i;
2903
2904 for (i = 0; i < num_adm_permitted_opens; i++)
2905 if (permitted_adm_opens[i].host_to_connect != NULL)
2906 xfree(permitted_adm_opens[i].host_to_connect);
2907 num_adm_permitted_opens = 0;
2908 }
2909
2910 void
2911 channel_print_adm_permitted_opens(void)
2912 {
2913 int i;
2914
2915 printf("permitopen");
2916 if (num_adm_permitted_opens == 0) {
2917 printf(" any\n");
2918 return;
2919 }
2920 for (i = 0; i < num_adm_permitted_opens; i++)
2921 if (permitted_adm_opens[i].host_to_connect != NULL)
2922 printf(" %s:%d", permitted_adm_opens[i].host_to_connect,
2923 permitted_adm_opens[i].port_to_connect);
2924 printf("\n");
2925 }
2926
2927 /* Try to start non-blocking connect to next host in cctx list */
2928 static int
2929 connect_next(struct channel_connect *cctx)
2930 {
2931 int sock, saved_errno;
2932 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2933
2934 for (; cctx->ai; cctx->ai = cctx->ai->ai_next) {
2935 if (cctx->ai->ai_family != AF_INET &&
2936 cctx->ai->ai_family != AF_INET6)
2937 continue;
2938 if (getnameinfo(cctx->ai->ai_addr, cctx->ai->ai_addrlen,
2939 ntop, sizeof(ntop), strport, sizeof(strport),
2940 NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2941 error("connect_next: getnameinfo failed");
2942 continue;
2943 }
2944 if ((sock = socket(cctx->ai->ai_family, cctx->ai->ai_socktype,
2945 cctx->ai->ai_protocol)) == -1) {
2946 if (cctx->ai->ai_next == NULL)
2947 error("socket: %.100s", strerror(errno));
2948 else
2949 verbose("socket: %.100s", strerror(errno));
2950 continue;
2951 }
2952 if (set_nonblock(sock) == -1)
2953 fatal("%s: set_nonblock(%d)", __func__, sock);
2954 if (connect(sock, cctx->ai->ai_addr,
2955 cctx->ai->ai_addrlen) == -1 && errno != EINPROGRESS) {
2956 debug("connect_next: host %.100s ([%.100s]:%s): "
2957 "%.100s", cctx->host, ntop, strport,
2958 strerror(errno));
2959 saved_errno = errno;
2960 close(sock);
2961 errno = saved_errno;
2962 continue; /* fail -- try next */
2963 }
2964 debug("connect_next: host %.100s ([%.100s]:%s) "
2965 "in progress, fd=%d", cctx->host, ntop, strport, sock);
2966 cctx->ai = cctx->ai->ai_next;
2967 set_nodelay(sock);
2968 return sock;
2969 }
2970 return -1;
2971 }
2972
2973 static void
2974 channel_connect_ctx_free(struct channel_connect *cctx)
2975 {
2976 xfree(cctx->host);
2977 if (cctx->aitop)
2978 freeaddrinfo(cctx->aitop);
2979 bzero(cctx, sizeof(*cctx));
2980 cctx->host = NULL;
2981 cctx->ai = cctx->aitop = NULL;
2982 }
2983
2984 /* Return CONNECTING channel to remote host, port */
2985 static Channel *
2986 connect_to(const char *host, u_short port, char *ctype, char *rname)
2987 {
2988 struct addrinfo hints;
2989 int gaierr;
2990 int sock = -1;
2991 char strport[NI_MAXSERV];
2992 struct channel_connect cctx;
2993 Channel *c;
2994
2995 memset(&cctx, 0, sizeof(cctx));
2996 memset(&hints, 0, sizeof(hints));
2997 hints.ai_family = IPv4or6;
2998 hints.ai_socktype = SOCK_STREAM;
2999 snprintf(strport, sizeof strport, "%d", port);
3000 if ((gaierr = getaddrinfo(host, strport, &hints, &cctx.aitop)) != 0) {
3001 error("connect_to %.100s: unknown host (%s)", host,
3002 ssh_gai_strerror(gaierr));
3003 return NULL;
3004 }
3005
3006 cctx.host = xstrdup(host);
3007 cctx.port = port;
3008 cctx.ai = cctx.aitop;
3009
3010 if ((sock = connect_next(&cctx)) == -1) {
3011 error("connect to %.100s port %d failed: %s",
3012 host, port, strerror(errno));
3013 channel_connect_ctx_free(&cctx);
3014 return NULL;
3015 }
3016 c = channel_new(ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1,
3017 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1);
3018 c->connect_ctx = cctx;
3019 return c;
3020 }
3021
3022 Channel *
3023 channel_connect_by_listen_address(u_short listen_port, char *ctype, char *rname)
3024 {
3025 int i;
3026
3027 for (i = 0; i < num_permitted_opens; i++) {
3028 if (permitted_opens[i].host_to_connect != NULL &&
3029 permitted_opens[i].listen_port == listen_port) {
3030 return connect_to(
3031 permitted_opens[i].host_to_connect,
3032 permitted_opens[i].port_to_connect, ctype, rname);
3033 }
3034 }
3035 error("WARNING: Server requests forwarding for unknown listen_port %d",
3036 listen_port);
3037 return NULL;
3038 }
3039
3040 /* Check if connecting to that port is permitted and connect. */
3041 Channel *
3042 channel_connect_to(const char *host, u_short port, char *ctype, char *rname)
3043 {
3044 int i, permit, permit_adm = 1;
3045
3046 permit = all_opens_permitted;
3047 if (!permit) {
3048 for (i = 0; i < num_permitted_opens; i++)
3049 if (permitted_opens[i].host_to_connect != NULL &&
3050 permitted_opens[i].port_to_connect == port &&
3051 strcmp(permitted_opens[i].host_to_connect, host) == 0)
3052 permit = 1;
3053 }
3054
3055 if (num_adm_permitted_opens > 0) {
3056 permit_adm = 0;
3057 for (i = 0; i < num_adm_permitted_opens; i++)
3058 if (permitted_adm_opens[i].host_to_connect != NULL &&
3059 permitted_adm_opens[i].port_to_connect == port &&
3060 strcmp(permitted_adm_opens[i].host_to_connect, host)
3061 == 0)
3062 permit_adm = 1;
3063 }
3064
3065 if (!permit || !permit_adm) {
3066 logit("Received request to connect to host %.100s port %d, "
3067 "but the request was denied.", host, port);
3068 return NULL;
3069 }
3070 return connect_to(host, port, ctype, rname);
3071 }
3072
3073 void
3074 channel_send_window_changes(void)
3075 {
3076 u_int i;
3077 struct winsize ws;
3078
3079 for (i = 0; i < channels_alloc; i++) {
3080 if (channels[i] == NULL || !channels[i]->client_tty ||
3081 channels[i]->type != SSH_CHANNEL_OPEN)
3082 continue;
3083 if (ioctl(channels[i]->rfd, TIOCGWINSZ, &ws) < 0)
3084 continue;
3085 channel_request_start(i, "window-change", 0);
3086 packet_put_int((u_int)ws.ws_col);
3087 packet_put_int((u_int)ws.ws_row);
3088 packet_put_int((u_int)ws.ws_xpixel);
3089 packet_put_int((u_int)ws.ws_ypixel);
3090 packet_send();
3091 }
3092 }
3093
3094 /* -- X11 forwarding */
3095
3096 /*
3097 * Creates an internet domain socket for listening for X11 connections.
3098 * Returns 0 and a suitable display number for the DISPLAY variable
3099 * stored in display_numberp , or -1 if an error occurs.
3100 */
3101 int
3102 x11_create_display_inet(int x11_display_offset, int x11_use_localhost,
3103 int single_connection, u_int *display_numberp, int **chanids)
3104 {
3105 Channel *nc = NULL;
3106 int display_number, sock;
3107 u_short port;
3108 struct addrinfo hints, *ai, *aitop;
3109 char strport[NI_MAXSERV];
3110 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
3111
3112 if (chanids == NULL)
3113 return -1;
3114
3115 for (display_number = x11_display_offset;
3116 display_number < MAX_DISPLAYS;
3117 display_number++) {
3118 port = 6000 + display_number;
3119 memset(&hints, 0, sizeof(hints));
3120 hints.ai_family = IPv4or6;
3121 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE;
3122 hints.ai_socktype = SOCK_STREAM;
3123 snprintf(strport, sizeof strport, "%d", port);
3124 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
3125 error("getaddrinfo: %.100s", ssh_gai_strerror(gaierr));
3126 return -1;
3127 }
3128 for (ai = aitop; ai; ai = ai->ai_next) {
3129 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
3130 continue;
3131 sock = socket(ai->ai_family, ai->ai_socktype,
3132 ai->ai_protocol);
3133 if (sock < 0) {
3134 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
3135 error("socket: %.100s", strerror(errno));
3136 freeaddrinfo(aitop);
3137 return -1;
3138 } else {
3139 debug("x11_create_display_inet: Socket family %d not supported",
3140 ai->ai_family);
3141 continue;
3142 }
3143 }
3144 if (ai->ai_family == AF_INET6)
3145 sock_set_v6only(sock);
3146 if (x11_use_localhost)
3147 channel_set_reuseaddr(sock);
3148 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
3149 debug2("bind port %d: %.100s", port, strerror(errno));
3150 close(sock);
3151
3152 for (n = 0; n < num_socks; n++) {
3153 close(socks[n]);
3154 }
3155 num_socks = 0;
3156 break;
3157 }
3158 socks[num_socks++] = sock;
3159 if (num_socks == NUM_SOCKS)
3160 break;
3161 }
3162 freeaddrinfo(aitop);
3163 if (num_socks > 0)
3164 break;
3165 }
3166 if (display_number >= MAX_DISPLAYS) {
3167 error("Failed to allocate internet-domain X11 display socket.");
3168 return -1;
3169 }
3170 /* Start listening for connections on the socket. */
3171 for (n = 0; n < num_socks; n++) {
3172 sock = socks[n];
3173 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
3174 error("listen: %.100s", strerror(errno));
3175 close(sock);
3176 return -1;
3177 }
3178 }
3179
3180 /* Allocate a channel for each socket. */
3181 *chanids = xcalloc(num_socks + 1, sizeof(**chanids));
3182 for (n = 0; n < num_socks; n++) {
3183 sock = socks[n];
3184 nc = channel_new("x11 listener",
3185 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
3186 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
3187 0, "X11 inet listener", 1);
3188 nc->single_connection = single_connection;
3189 (*chanids)[n] = nc->self;
3190 }
3191 (*chanids)[n] = -1;
3192
3193 /* Return the display number for the DISPLAY environment variable. */
3194 *display_numberp = display_number;
3195 return (0);
3196 }
3197
3198 static int
3199 connect_local_xsocket_path(const char *pathname)
3200 {
3201 int sock;
3202 struct sockaddr_un addr;
3203
3204 sock = socket(AF_UNIX, SOCK_STREAM, 0);
3205 if (sock < 0)
3206 error("socket: %.100s", strerror(errno));
3207 memset(&addr, 0, sizeof(addr));
3208 addr.sun_family = AF_UNIX;
3209 strlcpy(addr.sun_path, pathname, sizeof addr.sun_path);
3210 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0)
3211 return sock;
3212 close(sock);
3213 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
3214 return -1;
3215 }
3216
3217 static int
3218 connect_local_xsocket(u_int dnr)
3219 {
3220 char buf[1024];
3221 snprintf(buf, sizeof buf, _PATH_UNIX_X, dnr);
3222 return connect_local_xsocket_path(buf);
3223 }
3224
3225 int
3226 x11_connect_display(void)
3227 {
3228 u_int display_number;
3229 const char *display;
3230 char buf[1024], *cp;
3231 struct addrinfo hints, *ai, *aitop;
3232 char strport[NI_MAXSERV];
3233 int gaierr, sock = 0;
3234
3235 /* Try to open a socket for the local X server. */
3236 display = getenv("DISPLAY");
3237 if (!display) {
3238 error("DISPLAY not set.");
3239 return -1;
3240 }
3241 /*
3242 * Now we decode the value of the DISPLAY variable and make a
3243 * connection to the real X server.
3244 */
3245
3246 /* Check if the display is from launchd. */
3247 #ifdef __APPLE__
3248 if (strncmp(display, "/tmp/launch", 11) == 0) {
3249 sock = connect_local_xsocket_path(display);
3250 if (sock < 0)
3251 return -1;
3252
3253 /* OK, we now have a connection to the display. */
3254 return sock;
3255 }
3256 #endif
3257 /*
3258 * Check if it is a unix domain socket. Unix domain displays are in
3259 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
3260 */
3261 if (strncmp(display, "unix:", 5) == 0 ||
3262 display[0] == ':') {
3263 /* Connect to the unix domain socket. */
3264 if (sscanf(strrchr(display, ':') + 1, "%u", &display_number) != 1) {
3265 error("Could not parse display number from DISPLAY: %.100s",
3266 display);
3267 return -1;
3268 }
3269 /* Create a socket. */
3270 sock = connect_local_xsocket(display_number);
3271 if (sock < 0)
3272 return -1;
3273
3274 /* OK, we now have a connection to the display. */
3275 return sock;
3276 }
3277 /*
3278 * Connect to an inet socket. The DISPLAY value is supposedly
3279 * hostname:d[.s], where hostname may also be numeric IP address.
3280 */
3281 strlcpy(buf, display, sizeof(buf));
3282 cp = strchr(buf, ':');
3283 if (!cp) {
3284 error("Could not find ':' in DISPLAY: %.100s", display);
3285 return -1;
3286 }
3287 *cp = 0;
3288 /* buf now contains the host name. But first we parse the display number. */
3289 if (sscanf(cp + 1, "%u", &display_number) != 1) {
3290 error("Could not parse display number from DISPLAY: %.100s",
3291 display);
3292 return -1;
3293 }
3294
3295 /* Look up the host address */
3296 memset(&hints, 0, sizeof(hints));
3297 hints.ai_family = IPv4or6;
3298 hints.ai_socktype = SOCK_STREAM;
3299 snprintf(strport, sizeof strport, "%u", 6000 + display_number);
3300 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
3301 error("%.100s: unknown host. (%s)", buf,
3302 ssh_gai_strerror(gaierr));
3303 return -1;
3304 }
3305 for (ai = aitop; ai; ai = ai->ai_next) {
3306 /* Create a socket. */
3307 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
3308 if (sock < 0) {
3309 debug2("socket: %.100s", strerror(errno));
3310 continue;
3311 }
3312 /* Connect it to the display. */
3313 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
3314 debug2("connect %.100s port %u: %.100s", buf,
3315 6000 + display_number, strerror(errno));
3316 close(sock);
3317 continue;
3318 }
3319 /* Success */
3320 break;
3321 }
3322 freeaddrinfo(aitop);
3323 if (!ai) {
3324 error("connect %.100s port %u: %.100s", buf, 6000 + display_number,
3325 strerror(errno));
3326 return -1;
3327 }
3328 set_nodelay(sock);
3329 return sock;
3330 }
3331
3332 /*
3333 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
3334 * the remote channel number. We should do whatever we want, and respond
3335 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
3336 */
3337
3338 /* ARGSUSED */
3339 void
3340 x11_input_open(int type, u_int32_t seq, void *ctxt)
3341 {
3342 Channel *c = NULL;
3343 int remote_id, sock = 0;
3344 char *remote_host;
3345
3346 debug("Received X11 open request.");
3347
3348 remote_id = packet_get_int();
3349
3350 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
3351 remote_host = packet_get_string(NULL);
3352 } else {
3353 remote_host = xstrdup("unknown (remote did not supply name)");
3354 }
3355 packet_check_eom();
3356
3357 /* Obtain a connection to the real X display. */
3358 sock = x11_connect_display();
3359 if (sock != -1) {
3360 /* Allocate a channel for this connection. */
3361 c = channel_new("connected x11 socket",
3362 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
3363 remote_host, 1);
3364 c->remote_id = remote_id;
3365 c->force_drain = 1;
3366 }
3367 xfree(remote_host);
3368 if (c == NULL) {
3369 /* Send refusal to the remote host. */
3370 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3371 packet_put_int(remote_id);
3372 } else {
3373 /* Send a confirmation to the remote host. */
3374 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
3375 packet_put_int(remote_id);
3376 packet_put_int(c->self);
3377 }
3378 packet_send();
3379 }
3380
3381 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
3382 /* ARGSUSED */
3383 void
3384 deny_input_open(int type, u_int32_t seq, void *ctxt)
3385 {
3386 int rchan = packet_get_int();
3387
3388 switch (type) {
3389 case SSH_SMSG_AGENT_OPEN:
3390 error("Warning: ssh server tried agent forwarding.");
3391 break;
3392 case SSH_SMSG_X11_OPEN:
3393 error("Warning: ssh server tried X11 forwarding.");
3394 break;
3395 default:
3396 error("deny_input_open: type %d", type);
3397 break;
3398 }
3399 error("Warning: this is probably a break-in attempt by a malicious server.");
3400 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3401 packet_put_int(rchan);
3402 packet_send();
3403 }
3404
3405 /*
3406 * Requests forwarding of X11 connections, generates fake authentication
3407 * data, and enables authentication spoofing.
3408 * This should be called in the client only.
3409 */
3410 void
3411 x11_request_forwarding_with_spoofing(int client_session_id, const char *disp,
3412 const char *proto, const char *data)
3413 {
3414 u_int data_len = (u_int) strlen(data) / 2;
3415 u_int i, value;
3416 char *new_data;
3417 int screen_number;
3418 const char *cp;
3419 u_int32_t rnd = 0;
3420
3421 if (x11_saved_display == NULL)
3422 x11_saved_display = xstrdup(disp);
3423 else if (strcmp(disp, x11_saved_display) != 0) {
3424 error("x11_request_forwarding_with_spoofing: different "
3425 "$DISPLAY already forwarded");
3426 return;
3427 }
3428
3429 cp = strchr(disp, ':');
3430 if (cp)
3431 cp = strchr(cp, '.');
3432 if (cp)
3433 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL);
3434 else
3435 screen_number = 0;
3436
3437 if (x11_saved_proto == NULL) {
3438 /* Save protocol name. */
3439 x11_saved_proto = xstrdup(proto);
3440 /*
3441 * Extract real authentication data and generate fake data
3442 * of the same length.
3443 */
3444 x11_saved_data = xmalloc(data_len);
3445 x11_fake_data = xmalloc(data_len);
3446 for (i = 0; i < data_len; i++) {
3447 if (sscanf(data + 2 * i, "%2x", &value) != 1)
3448 fatal("x11_request_forwarding: bad "
3449 "authentication data: %.100s", data);
3450 if (i % 4 == 0)
3451 rnd = arc4random();
3452 x11_saved_data[i] = value;
3453 x11_fake_data[i] = rnd & 0xff;
3454 rnd >>= 8;
3455 }
3456 x11_saved_data_len = data_len;
3457 x11_fake_data_len = data_len;
3458 }
3459
3460 /* Convert the fake data into hex. */
3461 new_data = tohex(x11_fake_data, data_len);
3462
3463 /* Send the request packet. */
3464 if (compat20) {
3465 channel_request_start(client_session_id, "x11-req", 0);
3466 packet_put_char(0); /* XXX bool single connection */
3467 } else {
3468 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
3469 }
3470 packet_put_cstring(proto);
3471 packet_put_cstring(new_data);
3472 packet_put_int(screen_number);
3473 packet_send();
3474 packet_write_wait();
3475 xfree(new_data);
3476 }
3477
3478
3479 /* -- agent forwarding */
3480
3481 /* Sends a message to the server to request authentication fd forwarding. */
3482
3483 void
3484 auth_request_forwarding(void)
3485 {
3486 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
3487 packet_send();
3488 packet_write_wait();
3489 }
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