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utilities - Temporary map out libevtr, ktrdump, and evtranalyze from x86_64
[dragonfly.git] / crypto / openssh / channels.c
blobcbcd42e6872be2d8047eea378600c289a1ab1791
1 /* $OpenBSD: channels.c,v 1.296 2009/05/25 06:48:00 andreas 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 <netdb.h>
57 #include <stdio.h>
58 #include <stdlib.h>
59 #include <string.h>
60 #include <termios.h>
61 #include <unistd.h>
62 #include <stdarg.h>
63
64 #include "openbsd-compat/sys-queue.h"
65 #include "xmalloc.h"
66 #include "ssh.h"
67 #include "ssh1.h"
68 #include "ssh2.h"
69 #include "packet.h"
70 #include "log.h"
71 #include "misc.h"
72 #include "buffer.h"
73 #include "channels.h"
74 #include "compat.h"
75 #include "canohost.h"
76 #include "key.h"
77 #include "authfd.h"
78 #include "pathnames.h"
79
80 /* -- channel core */
81
82 /*
83 * Pointer to an array containing all allocated channels. The array is
84 * dynamically extended as needed.
85 */
86 static Channel **channels = NULL;
87
88 /*
89 * Size of the channel array. All slots of the array must always be
90 * initialized (at least the type field); unused slots set to NULL
91 */
92 static u_int channels_alloc = 0;
93
94 /*
95 * Maximum file descriptor value used in any of the channels. This is
96 * updated in channel_new.
97 */
98 static int channel_max_fd = 0;
99
100
101 /* -- tcp forwarding */
102
103 /*
104 * Data structure for storing which hosts are permitted for forward requests.
105 * The local sides of any remote forwards are stored in this array to prevent
106 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local
107 * network (which might be behind a firewall).
108 */
109 typedef struct {
110 char *host_to_connect; /* Connect to 'host'. */
111 u_short port_to_connect; /* Connect to 'port'. */
112 u_short listen_port; /* Remote side should listen port number. */
113 } ForwardPermission;
114
115 /* List of all permitted host/port pairs to connect by the user. */
116 static ForwardPermission permitted_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
117
118 /* List of all permitted host/port pairs to connect by the admin. */
119 static ForwardPermission permitted_adm_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
120
121 /* Number of permitted host/port pairs in the array permitted by the user. */
122 static int num_permitted_opens = 0;
123
124 /* Number of permitted host/port pair in the array permitted by the admin. */
125 static int num_adm_permitted_opens = 0;
126
127 /*
128 * If this is true, all opens are permitted. This is the case on the server
129 * on which we have to trust the client anyway, and the user could do
130 * anything after logging in anyway.
131 */
132 static int all_opens_permitted = 0;
133
134
135 /* -- X11 forwarding */
136
137 /* Maximum number of fake X11 displays to try. */
138 #define MAX_DISPLAYS 1000
139
140 /* Saved X11 local (client) display. */
141 static char *x11_saved_display = NULL;
142
143 /* Saved X11 authentication protocol name. */
144 static char *x11_saved_proto = NULL;
145
146 /* Saved X11 authentication data. This is the real data. */
147 static char *x11_saved_data = NULL;
148 static u_int x11_saved_data_len = 0;
149
150 /*
151 * Fake X11 authentication data. This is what the server will be sending us;
152 * we should replace any occurrences of this by the real data.
153 */
154 static u_char *x11_fake_data = NULL;
155 static u_int x11_fake_data_len;
156
157
158 /* -- agent forwarding */
159
160 #define NUM_SOCKS 10
161
162 /* AF_UNSPEC or AF_INET or AF_INET6 */
163 static int IPv4or6 = AF_UNSPEC;
164
165 /* helper */
166 static void port_open_helper(Channel *c, char *rtype);
167
168 /* non-blocking connect helpers */
169 static int connect_next(struct channel_connect *);
170 static void channel_connect_ctx_free(struct channel_connect *);
171
172
173 static int hpn_disabled = 0;
174 static int hpn_buffer_size = 2 * 1024 * 1024;
175
176 /* -- channel core */
177
178
179
180 Channel *
181 channel_by_id(int id)
182 {
183 Channel *c;
184
185 if (id < 0 || (u_int)id >= channels_alloc) {
186 logit("channel_by_id: %d: bad id", id);
187 return NULL;
188 }
189 c = channels[id];
190 if (c == NULL) {
191 logit("channel_by_id: %d: bad id: channel free", id);
192 return NULL;
193 }
194 return c;
195 }
196
197 /*
198 * Returns the channel if it is allowed to receive protocol messages.
199 * Private channels, like listening sockets, may not receive messages.
200 */
201 Channel *
202 channel_lookup(int id)
203 {
204 Channel *c;
205
206 if ((c = channel_by_id(id)) == NULL)
207 return (NULL);
208
209 switch (c->type) {
210 case SSH_CHANNEL_X11_OPEN:
211 case SSH_CHANNEL_LARVAL:
212 case SSH_CHANNEL_CONNECTING:
213 case SSH_CHANNEL_DYNAMIC:
214 case SSH_CHANNEL_OPENING:
215 case SSH_CHANNEL_OPEN:
216 case SSH_CHANNEL_INPUT_DRAINING:
217 case SSH_CHANNEL_OUTPUT_DRAINING:
218 return (c);
219 }
220 logit("Non-public channel %d, type %d.", id, c->type);
221 return (NULL);
222 }
223
224 /*
225 * Register filedescriptors for a channel, used when allocating a channel or
226 * when the channel consumer/producer is ready, e.g. shell exec'd
227 */
228 static void
229 channel_register_fds(Channel *c, int rfd, int wfd, int efd,
230 int extusage, int nonblock, int is_tty)
231 {
232 /* Update the maximum file descriptor value. */
233 channel_max_fd = MAX(channel_max_fd, rfd);
234 channel_max_fd = MAX(channel_max_fd, wfd);
235 channel_max_fd = MAX(channel_max_fd, efd);
236
237 /* XXX set close-on-exec -markus */
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->dynamic_window = 0;
318 c->remote_id = -1;
319 c->remote_name = xstrdup(remote_name);
320 c->remote_window = 0;
321 c->remote_maxpacket = 0;
322 c->force_drain = 0;
323 c->single_connection = 0;
324 c->detach_user = NULL;
325 c->detach_close = 0;
326 c->open_confirm = NULL;
327 c->open_confirm_ctx = NULL;
328 c->input_filter = NULL;
329 c->output_filter = NULL;
330 c->filter_ctx = NULL;
331 c->filter_cleanup = NULL;
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 int channel_tcpwinsz () {
809 u_int32_t tcpwinsz = 0;
810 socklen_t optsz = sizeof(tcpwinsz);
811 int ret = -1;
812
813 /* if we aren't on a socket return 128KB*/
814 if(!packet_connection_is_on_socket())
815 return(128*1024);
816 ret = getsockopt(packet_get_connection_in(),
817 SOL_SOCKET, SO_RCVBUF, &tcpwinsz, &optsz);
818 /* return no more than 64MB */
819 if ((ret == 0) && tcpwinsz > BUFFER_MAX_LEN_HPN)
820 tcpwinsz = BUFFER_MAX_LEN_HPN;
821 debug2("tcpwinsz: %d for connection: %d", tcpwinsz,
822 packet_get_connection_in());
823 return(tcpwinsz);
824 }
825
826 static void
827 channel_pre_open(Channel *c, fd_set *readset, fd_set *writeset)
828 {
829 u_int limit = compat20 ? c->remote_window : packet_get_maxsize();
830
831 /* check buffer limits */
832 if ((!c->tcpwinsz) || (c->dynamic_window > 0))
833 c->tcpwinsz = channel_tcpwinsz();
834
835 limit = MIN(limit, 2 * c->tcpwinsz);
836
837 if (c->istate == CHAN_INPUT_OPEN &&
838 limit > 0 &&
839 buffer_len(&c->input) < limit &&
840 buffer_check_alloc(&c->input, CHAN_RBUF))
841 FD_SET(c->rfd, readset);
842 if (c->ostate == CHAN_OUTPUT_OPEN ||
843 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
844 if (buffer_len(&c->output) > 0) {
845 FD_SET(c->wfd, writeset);
846 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
847 if (CHANNEL_EFD_OUTPUT_ACTIVE(c))
848 debug2("channel %d: obuf_empty delayed efd %d/(%d)",
849 c->self, c->efd, buffer_len(&c->extended));
850 else
851 chan_obuf_empty(c);
852 }
853 }
854 /** XXX check close conditions, too */
855 if (compat20 && c->efd != -1 &&
856 !(c->istate == CHAN_INPUT_CLOSED && c->ostate == CHAN_OUTPUT_CLOSED)) {
857 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
858 buffer_len(&c->extended) > 0)
859 FD_SET(c->efd, writeset);
860 else if (!(c->flags & CHAN_EOF_SENT) &&
861 c->extended_usage == CHAN_EXTENDED_READ &&
862 buffer_len(&c->extended) < c->remote_window)
863 FD_SET(c->efd, readset);
864 }
865 /* XXX: What about efd? races? */
866 if (compat20 && c->ctl_fd != -1 &&
867 c->istate == CHAN_INPUT_OPEN && c->ostate == CHAN_OUTPUT_OPEN)
868 FD_SET(c->ctl_fd, readset);
869 }
870
871 /* ARGSUSED */
872 static void
873 channel_pre_input_draining(Channel *c, fd_set *readset, fd_set *writeset)
874 {
875 if (buffer_len(&c->input) == 0) {
876 packet_start(SSH_MSG_CHANNEL_CLOSE);
877 packet_put_int(c->remote_id);
878 packet_send();
879 c->type = SSH_CHANNEL_CLOSED;
880 debug2("channel %d: closing after input drain.", c->self);
881 }
882 }
883
884 /* ARGSUSED */
885 static void
886 channel_pre_output_draining(Channel *c, fd_set *readset, fd_set *writeset)
887 {
888 if (buffer_len(&c->output) == 0)
889 chan_mark_dead(c);
890 else
891 FD_SET(c->sock, writeset);
892 }
893
894 /*
895 * This is a special state for X11 authentication spoofing. An opened X11
896 * connection (when authentication spoofing is being done) remains in this
897 * state until the first packet has been completely read. The authentication
898 * data in that packet is then substituted by the real data if it matches the
899 * fake data, and the channel is put into normal mode.
900 * XXX All this happens at the client side.
901 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
902 */
903 static int
904 x11_open_helper(Buffer *b)
905 {
906 u_char *ucp;
907 u_int proto_len, data_len;
908
909 /* Check if the fixed size part of the packet is in buffer. */
910 if (buffer_len(b) < 12)
911 return 0;
912
913 /* Parse the lengths of variable-length fields. */
914 ucp = buffer_ptr(b);
915 if (ucp[0] == 0x42) { /* Byte order MSB first. */
916 proto_len = 256 * ucp[6] + ucp[7];
917 data_len = 256 * ucp[8] + ucp[9];
918 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
919 proto_len = ucp[6] + 256 * ucp[7];
920 data_len = ucp[8] + 256 * ucp[9];
921 } else {
922 debug2("Initial X11 packet contains bad byte order byte: 0x%x",
923 ucp[0]);
924 return -1;
925 }
926
927 /* Check if the whole packet is in buffer. */
928 if (buffer_len(b) <
929 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
930 return 0;
931
932 /* Check if authentication protocol matches. */
933 if (proto_len != strlen(x11_saved_proto) ||
934 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
935 debug2("X11 connection uses different authentication protocol.");
936 return -1;
937 }
938 /* Check if authentication data matches our fake data. */
939 if (data_len != x11_fake_data_len ||
940 memcmp(ucp + 12 + ((proto_len + 3) & ~3),
941 x11_fake_data, x11_fake_data_len) != 0) {
942 debug2("X11 auth data does not match fake data.");
943 return -1;
944 }
945 /* Check fake data length */
946 if (x11_fake_data_len != x11_saved_data_len) {
947 error("X11 fake_data_len %d != saved_data_len %d",
948 x11_fake_data_len, x11_saved_data_len);
949 return -1;
950 }
951 /*
952 * Received authentication protocol and data match
953 * our fake data. Substitute the fake data with real
954 * data.
955 */
956 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
957 x11_saved_data, x11_saved_data_len);
958 return 1;
959 }
960
961 static void
962 channel_pre_x11_open_13(Channel *c, fd_set *readset, fd_set *writeset)
963 {
964 int ret = x11_open_helper(&c->output);
965
966 if (ret == 1) {
967 /* Start normal processing for the channel. */
968 c->type = SSH_CHANNEL_OPEN;
969 channel_pre_open_13(c, readset, writeset);
970 } else if (ret == -1) {
971 /*
972 * We have received an X11 connection that has bad
973 * authentication information.
974 */
975 logit("X11 connection rejected because of wrong authentication.");
976 buffer_clear(&c->input);
977 buffer_clear(&c->output);
978 channel_close_fd(&c->sock);
979 c->sock = -1;
980 c->type = SSH_CHANNEL_CLOSED;
981 packet_start(SSH_MSG_CHANNEL_CLOSE);
982 packet_put_int(c->remote_id);
983 packet_send();
984 }
985 }
986
987 static void
988 channel_pre_x11_open(Channel *c, fd_set *readset, fd_set *writeset)
989 {
990 int ret = x11_open_helper(&c->output);
991
992 /* c->force_drain = 1; */
993
994 if (ret == 1) {
995 c->type = SSH_CHANNEL_OPEN;
996 channel_pre_open(c, readset, writeset);
997 } else if (ret == -1) {
998 logit("X11 connection rejected because of wrong authentication.");
999 debug2("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
1000 chan_read_failed(c);
1001 buffer_clear(&c->input);
1002 chan_ibuf_empty(c);
1003 buffer_clear(&c->output);
1004 /* for proto v1, the peer will send an IEOF */
1005 if (compat20)
1006 chan_write_failed(c);
1007 else
1008 c->type = SSH_CHANNEL_OPEN;
1009 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
1010 }
1011 }
1012
1013 /* try to decode a socks4 header */
1014 /* ARGSUSED */
1015 static int
1016 channel_decode_socks4(Channel *c, fd_set *readset, fd_set *writeset)
1017 {
1018 char *p, *host;
1019 u_int len, have, i, found, need;
1020 char username[256];
1021 struct {
1022 u_int8_t version;
1023 u_int8_t command;
1024 u_int16_t dest_port;
1025 struct in_addr dest_addr;
1026 } s4_req, s4_rsp;
1027
1028 debug2("channel %d: decode socks4", c->self);
1029
1030 have = buffer_len(&c->input);
1031 len = sizeof(s4_req);
1032 if (have < len)
1033 return 0;
1034 p = buffer_ptr(&c->input);
1035
1036 need = 1;
1037 /* SOCKS4A uses an invalid IP address 0.0.0.x */
1038 if (p[4] == 0 && p[5] == 0 && p[6] == 0 && p[7] != 0) {
1039 debug2("channel %d: socks4a request", c->self);
1040 /* ... and needs an extra string (the hostname) */
1041 need = 2;
1042 }
1043 /* Check for terminating NUL on the string(s) */
1044 for (found = 0, i = len; i < have; i++) {
1045 if (p[i] == '\0') {
1046 found++;
1047 if (found == need)
1048 break;
1049 }
1050 if (i > 1024) {
1051 /* the peer is probably sending garbage */
1052 debug("channel %d: decode socks4: too long",
1053 c->self);
1054 return -1;
1055 }
1056 }
1057 if (found < need)
1058 return 0;
1059 buffer_get(&c->input, (char *)&s4_req.version, 1);
1060 buffer_get(&c->input, (char *)&s4_req.command, 1);
1061 buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
1062 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
1063 have = buffer_len(&c->input);
1064 p = buffer_ptr(&c->input);
1065 len = strlen(p);
1066 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
1067 len++; /* trailing '\0' */
1068 if (len > have)
1069 fatal("channel %d: decode socks4: len %d > have %d",
1070 c->self, len, have);
1071 strlcpy(username, p, sizeof(username));
1072 buffer_consume(&c->input, len);
1073
1074 if (c->path != NULL) {
1075 xfree(c->path);
1076 c->path = NULL;
1077 }
1078 if (need == 1) { /* SOCKS4: one string */
1079 host = inet_ntoa(s4_req.dest_addr);
1080 c->path = xstrdup(host);
1081 } else { /* SOCKS4A: two strings */
1082 have = buffer_len(&c->input);
1083 p = buffer_ptr(&c->input);
1084 len = strlen(p);
1085 debug2("channel %d: decode socks4a: host %s/%d",
1086 c->self, p, len);
1087 len++; /* trailing '\0' */
1088 if (len > have)
1089 fatal("channel %d: decode socks4a: len %d > have %d",
1090 c->self, len, have);
1091 if (len > NI_MAXHOST) {
1092 error("channel %d: hostname \"%.100s\" too long",
1093 c->self, p);
1094 return -1;
1095 }
1096 c->path = xstrdup(p);
1097 buffer_consume(&c->input, len);
1098 }
1099 c->host_port = ntohs(s4_req.dest_port);
1100
1101 debug2("channel %d: dynamic request: socks4 host %s port %u command %u",
1102 c->self, c->path, c->host_port, s4_req.command);
1103
1104 if (s4_req.command != 1) {
1105 debug("channel %d: cannot handle: %s cn %d",
1106 c->self, need == 1 ? "SOCKS4" : "SOCKS4A", s4_req.command);
1107 return -1;
1108 }
1109 s4_rsp.version = 0; /* vn: 0 for reply */
1110 s4_rsp.command = 90; /* cd: req granted */
1111 s4_rsp.dest_port = 0; /* ignored */
1112 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
1113 buffer_append(&c->output, &s4_rsp, sizeof(s4_rsp));
1114 return 1;
1115 }
1116
1117 /* try to decode a socks5 header */
1118 #define SSH_SOCKS5_AUTHDONE 0x1000
1119 #define SSH_SOCKS5_NOAUTH 0x00
1120 #define SSH_SOCKS5_IPV4 0x01
1121 #define SSH_SOCKS5_DOMAIN 0x03
1122 #define SSH_SOCKS5_IPV6 0x04
1123 #define SSH_SOCKS5_CONNECT 0x01
1124 #define SSH_SOCKS5_SUCCESS 0x00
1125
1126 /* ARGSUSED */
1127 static int
1128 channel_decode_socks5(Channel *c, fd_set *readset, fd_set *writeset)
1129 {
1130 struct {
1131 u_int8_t version;
1132 u_int8_t command;
1133 u_int8_t reserved;
1134 u_int8_t atyp;
1135 } s5_req, s5_rsp;
1136 u_int16_t dest_port;
1137 u_char *p, dest_addr[255+1], ntop[INET6_ADDRSTRLEN];
1138 u_int have, need, i, found, nmethods, addrlen, af;
1139
1140 debug2("channel %d: decode socks5", c->self);
1141 p = buffer_ptr(&c->input);
1142 if (p[0] != 0x05)
1143 return -1;
1144 have = buffer_len(&c->input);
1145 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) {
1146 /* format: ver | nmethods | methods */
1147 if (have < 2)
1148 return 0;
1149 nmethods = p[1];
1150 if (have < nmethods + 2)
1151 return 0;
1152 /* look for method: "NO AUTHENTICATION REQUIRED" */
1153 for (found = 0, i = 2; i < nmethods + 2; i++) {
1154 if (p[i] == SSH_SOCKS5_NOAUTH) {
1155 found = 1;
1156 break;
1157 }
1158 }
1159 if (!found) {
1160 debug("channel %d: method SSH_SOCKS5_NOAUTH not found",
1161 c->self);
1162 return -1;
1163 }
1164 buffer_consume(&c->input, nmethods + 2);
1165 buffer_put_char(&c->output, 0x05); /* version */
1166 buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH); /* method */
1167 FD_SET(c->sock, writeset);
1168 c->flags |= SSH_SOCKS5_AUTHDONE;
1169 debug2("channel %d: socks5 auth done", c->self);
1170 return 0; /* need more */
1171 }
1172 debug2("channel %d: socks5 post auth", c->self);
1173 if (have < sizeof(s5_req)+1)
1174 return 0; /* need more */
1175 memcpy(&s5_req, p, sizeof(s5_req));
1176 if (s5_req.version != 0x05 ||
1177 s5_req.command != SSH_SOCKS5_CONNECT ||
1178 s5_req.reserved != 0x00) {
1179 debug2("channel %d: only socks5 connect supported", c->self);
1180 return -1;
1181 }
1182 switch (s5_req.atyp){
1183 case SSH_SOCKS5_IPV4:
1184 addrlen = 4;
1185 af = AF_INET;
1186 break;
1187 case SSH_SOCKS5_DOMAIN:
1188 addrlen = p[sizeof(s5_req)];
1189 af = -1;
1190 break;
1191 case SSH_SOCKS5_IPV6:
1192 addrlen = 16;
1193 af = AF_INET6;
1194 break;
1195 default:
1196 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp);
1197 return -1;
1198 }
1199 need = sizeof(s5_req) + addrlen + 2;
1200 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1201 need++;
1202 if (have < need)
1203 return 0;
1204 buffer_consume(&c->input, sizeof(s5_req));
1205 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1206 buffer_consume(&c->input, 1); /* host string length */
1207 buffer_get(&c->input, (char *)&dest_addr, addrlen);
1208 buffer_get(&c->input, (char *)&dest_port, 2);
1209 dest_addr[addrlen] = '\0';
1210 if (c->path != NULL) {
1211 xfree(c->path);
1212 c->path = NULL;
1213 }
1214 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) {
1215 if (addrlen >= NI_MAXHOST) {
1216 error("channel %d: dynamic request: socks5 hostname "
1217 "\"%.100s\" too long", c->self, dest_addr);
1218 return -1;
1219 }
1220 c->path = xstrdup(dest_addr);
1221 } else {
1222 if (inet_ntop(af, dest_addr, ntop, sizeof(ntop)) == NULL)
1223 return -1;
1224 c->path = xstrdup(ntop);
1225 }
1226 c->host_port = ntohs(dest_port);
1227
1228 debug2("channel %d: dynamic request: socks5 host %s port %u command %u",
1229 c->self, c->path, c->host_port, s5_req.command);
1230
1231 s5_rsp.version = 0x05;
1232 s5_rsp.command = SSH_SOCKS5_SUCCESS;
1233 s5_rsp.reserved = 0; /* ignored */
1234 s5_rsp.atyp = SSH_SOCKS5_IPV4;
1235 ((struct in_addr *)&dest_addr)->s_addr = INADDR_ANY;
1236 dest_port = 0; /* ignored */
1237
1238 buffer_append(&c->output, &s5_rsp, sizeof(s5_rsp));
1239 buffer_append(&c->output, &dest_addr, sizeof(struct in_addr));
1240 buffer_append(&c->output, &dest_port, sizeof(dest_port));
1241 return 1;
1242 }
1243
1244 /* dynamic port forwarding */
1245 static void
1246 channel_pre_dynamic(Channel *c, fd_set *readset, fd_set *writeset)
1247 {
1248 u_char *p;
1249 u_int have;
1250 int ret;
1251
1252 have = buffer_len(&c->input);
1253 c->delayed = 0;
1254 debug2("channel %d: pre_dynamic: have %d", c->self, have);
1255 /* buffer_dump(&c->input); */
1256 /* check if the fixed size part of the packet is in buffer. */
1257 if (have < 3) {
1258 /* need more */
1259 FD_SET(c->sock, readset);
1260 return;
1261 }
1262 /* try to guess the protocol */
1263 p = buffer_ptr(&c->input);
1264 switch (p[0]) {
1265 case 0x04:
1266 ret = channel_decode_socks4(c, readset, writeset);
1267 break;
1268 case 0x05:
1269 ret = channel_decode_socks5(c, readset, writeset);
1270 break;
1271 default:
1272 ret = -1;
1273 break;
1274 }
1275 if (ret < 0) {
1276 chan_mark_dead(c);
1277 } else if (ret == 0) {
1278 debug2("channel %d: pre_dynamic: need more", c->self);
1279 /* need more */
1280 FD_SET(c->sock, readset);
1281 } else {
1282 /* switch to the next state */
1283 c->type = SSH_CHANNEL_OPENING;
1284 port_open_helper(c, "direct-tcpip");
1285 }
1286 }
1287
1288 /* This is our fake X11 server socket. */
1289 /* ARGSUSED */
1290 static void
1291 channel_post_x11_listener(Channel *c, fd_set *readset, fd_set *writeset)
1292 {
1293 Channel *nc;
1294 struct sockaddr_storage addr;
1295 int newsock;
1296 socklen_t addrlen;
1297 char buf[16384], *remote_ipaddr;
1298 int remote_port;
1299
1300 if (FD_ISSET(c->sock, readset)) {
1301 debug("X11 connection requested.");
1302 addrlen = sizeof(addr);
1303 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1304 if (c->single_connection) {
1305 debug2("single_connection: closing X11 listener.");
1306 channel_close_fd(&c->sock);
1307 chan_mark_dead(c);
1308 }
1309 if (newsock < 0) {
1310 error("accept: %.100s", strerror(errno));
1311 return;
1312 }
1313 set_nodelay(newsock);
1314 remote_ipaddr = get_peer_ipaddr(newsock);
1315 remote_port = get_peer_port(newsock);
1316 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1317 remote_ipaddr, remote_port);
1318
1319 nc = channel_new("accepted x11 socket",
1320 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1321 c->local_window_max, c->local_maxpacket, 0, buf, 1);
1322 if (compat20) {
1323 packet_start(SSH2_MSG_CHANNEL_OPEN);
1324 packet_put_cstring("x11");
1325 packet_put_int(nc->self);
1326 packet_put_int(nc->local_window_max);
1327 packet_put_int(nc->local_maxpacket);
1328 /* originator ipaddr and port */
1329 packet_put_cstring(remote_ipaddr);
1330 if (datafellows & SSH_BUG_X11FWD) {
1331 debug2("ssh2 x11 bug compat mode");
1332 } else {
1333 packet_put_int(remote_port);
1334 }
1335 packet_send();
1336 } else {
1337 packet_start(SSH_SMSG_X11_OPEN);
1338 packet_put_int(nc->self);
1339 if (packet_get_protocol_flags() &
1340 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1341 packet_put_cstring(buf);
1342 packet_send();
1343 }
1344 xfree(remote_ipaddr);
1345 }
1346 }
1347
1348 static void
1349 port_open_helper(Channel *c, char *rtype)
1350 {
1351 int direct;
1352 char buf[1024];
1353 char *remote_ipaddr = get_peer_ipaddr(c->sock);
1354 int remote_port = get_peer_port(c->sock);
1355
1356 direct = (strcmp(rtype, "direct-tcpip") == 0);
1357
1358 snprintf(buf, sizeof buf,
1359 "%s: listening port %d for %.100s port %d, "
1360 "connect from %.200s port %d",
1361 rtype, c->listening_port, c->path, c->host_port,
1362 remote_ipaddr, remote_port);
1363
1364 xfree(c->remote_name);
1365 c->remote_name = xstrdup(buf);
1366
1367 if (compat20) {
1368 packet_start(SSH2_MSG_CHANNEL_OPEN);
1369 packet_put_cstring(rtype);
1370 packet_put_int(c->self);
1371 packet_put_int(c->local_window_max);
1372 packet_put_int(c->local_maxpacket);
1373 if (direct) {
1374 /* target host, port */
1375 packet_put_cstring(c->path);
1376 packet_put_int(c->host_port);
1377 } else {
1378 /* listen address, port */
1379 packet_put_cstring(c->path);
1380 packet_put_int(c->listening_port);
1381 }
1382 /* originator host and port */
1383 packet_put_cstring(remote_ipaddr);
1384 packet_put_int((u_int)remote_port);
1385 packet_send();
1386 } else {
1387 packet_start(SSH_MSG_PORT_OPEN);
1388 packet_put_int(c->self);
1389 packet_put_cstring(c->path);
1390 packet_put_int(c->host_port);
1391 if (packet_get_protocol_flags() &
1392 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1393 packet_put_cstring(c->remote_name);
1394 packet_send();
1395 }
1396 xfree(remote_ipaddr);
1397 }
1398
1399 static void
1400 channel_set_reuseaddr(int fd)
1401 {
1402 int on = 1;
1403
1404 /*
1405 * Set socket options.
1406 * Allow local port reuse in TIME_WAIT.
1407 */
1408 if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1)
1409 error("setsockopt SO_REUSEADDR fd %d: %s", fd, strerror(errno));
1410 }
1411
1412 /*
1413 * This socket is listening for connections to a forwarded TCP/IP port.
1414 */
1415 /* ARGSUSED */
1416 static void
1417 channel_post_port_listener(Channel *c, fd_set *readset, fd_set *writeset)
1418 {
1419 Channel *nc;
1420 struct sockaddr_storage addr;
1421 int newsock, nextstate;
1422 socklen_t addrlen;
1423 char *rtype;
1424
1425 if (FD_ISSET(c->sock, readset)) {
1426 debug("Connection to port %d forwarding "
1427 "to %.100s port %d requested.",
1428 c->listening_port, c->path, c->host_port);
1429
1430 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1431 nextstate = SSH_CHANNEL_OPENING;
1432 rtype = "forwarded-tcpip";
1433 } else {
1434 if (c->host_port == 0) {
1435 nextstate = SSH_CHANNEL_DYNAMIC;
1436 rtype = "dynamic-tcpip";
1437 } else {
1438 nextstate = SSH_CHANNEL_OPENING;
1439 rtype = "direct-tcpip";
1440 }
1441 }
1442
1443 addrlen = sizeof(addr);
1444 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1445 if (newsock < 0) {
1446 error("accept: %.100s", strerror(errno));
1447 return;
1448 }
1449 set_nodelay(newsock);
1450 nc = channel_new(rtype, nextstate, newsock, newsock, -1,
1451 c->local_window_max, c->local_maxpacket, 0, rtype, 1);
1452 nc->listening_port = c->listening_port;
1453 nc->host_port = c->host_port;
1454 if (c->path != NULL)
1455 nc->path = xstrdup(c->path);
1456
1457 if (nextstate == SSH_CHANNEL_DYNAMIC) {
1458 /*
1459 * do not call the channel_post handler until
1460 * this flag has been reset by a pre-handler.
1461 * otherwise the FD_ISSET calls might overflow
1462 */
1463 nc->delayed = 1;
1464 } else {
1465 port_open_helper(nc, rtype);
1466 }
1467 }
1468 }
1469
1470 /*
1471 * This is the authentication agent socket listening for connections from
1472 * clients.
1473 */
1474 /* ARGSUSED */
1475 static void
1476 channel_post_auth_listener(Channel *c, fd_set *readset, fd_set *writeset)
1477 {
1478 Channel *nc;
1479 int newsock;
1480 struct sockaddr_storage addr;
1481 socklen_t addrlen;
1482
1483 if (FD_ISSET(c->sock, readset)) {
1484 addrlen = sizeof(addr);
1485 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1486 if (newsock < 0) {
1487 error("accept from auth socket: %.100s", strerror(errno));
1488 return;
1489 }
1490 nc = channel_new("accepted auth socket",
1491 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1492 c->local_window_max, c->local_maxpacket,
1493 0, "accepted auth socket", 1);
1494 if (compat20) {
1495 packet_start(SSH2_MSG_CHANNEL_OPEN);
1496 packet_put_cstring("auth-agent@openssh.com");
1497 packet_put_int(nc->self);
1498 packet_put_int(c->local_window_max);
1499 packet_put_int(c->local_maxpacket);
1500 } else {
1501 packet_start(SSH_SMSG_AGENT_OPEN);
1502 packet_put_int(nc->self);
1503 }
1504 packet_send();
1505 }
1506 }
1507
1508 /* ARGSUSED */
1509 static void
1510 channel_post_connecting(Channel *c, fd_set *readset, fd_set *writeset)
1511 {
1512 int err = 0, sock;
1513 socklen_t sz = sizeof(err);
1514
1515 if (FD_ISSET(c->sock, writeset)) {
1516 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) {
1517 err = errno;
1518 error("getsockopt SO_ERROR failed");
1519 }
1520 if (err == 0) {
1521 debug("channel %d: connected to %s port %d",
1522 c->self, c->connect_ctx.host, c->connect_ctx.port);
1523 channel_connect_ctx_free(&c->connect_ctx);
1524 c->type = SSH_CHANNEL_OPEN;
1525 if (compat20) {
1526 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1527 packet_put_int(c->remote_id);
1528 packet_put_int(c->self);
1529 packet_put_int(c->local_window);
1530 packet_put_int(c->local_maxpacket);
1531 } else {
1532 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1533 packet_put_int(c->remote_id);
1534 packet_put_int(c->self);
1535 }
1536 } else {
1537 debug("channel %d: connection failed: %s",
1538 c->self, strerror(err));
1539 /* Try next address, if any */
1540 if ((sock = connect_next(&c->connect_ctx)) > 0) {
1541 close(c->sock);
1542 c->sock = c->rfd = c->wfd = sock;
1543 channel_max_fd = channel_find_maxfd();
1544 return;
1545 }
1546 /* Exhausted all addresses */
1547 error("connect_to %.100s port %d: failed.",
1548 c->connect_ctx.host, c->connect_ctx.port);
1549 channel_connect_ctx_free(&c->connect_ctx);
1550 if (compat20) {
1551 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1552 packet_put_int(c->remote_id);
1553 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1554 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1555 packet_put_cstring(strerror(err));
1556 packet_put_cstring("");
1557 }
1558 } else {
1559 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1560 packet_put_int(c->remote_id);
1561 }
1562 chan_mark_dead(c);
1563 }
1564 packet_send();
1565 }
1566 }
1567
1568 /* ARGSUSED */
1569 static int
1570 channel_handle_rfd(Channel *c, fd_set *readset, fd_set *writeset)
1571 {
1572 char buf[CHAN_RBUF];
1573 int len, force;
1574
1575 force = c->isatty && c->detach_close && c->istate != CHAN_INPUT_CLOSED;
1576 if (c->rfd != -1 && (force || FD_ISSET(c->rfd, readset))) {
1577 errno = 0;
1578 len = read(c->rfd, buf, sizeof(buf));
1579 if (len < 0 && (errno == EINTR ||
1580 ((errno == EAGAIN || errno == EWOULDBLOCK) && !force)))
1581 return 1;
1582 #ifndef PTY_ZEROREAD
1583 if (len <= 0) {
1584 #else
1585 if ((!c->isatty && len <= 0) ||
1586 (c->isatty && (len < 0 || (len == 0 && errno != 0)))) {
1587 #endif
1588 debug2("channel %d: read<=0 rfd %d len %d",
1589 c->self, c->rfd, len);
1590 if (c->type != SSH_CHANNEL_OPEN) {
1591 debug2("channel %d: not open", c->self);
1592 chan_mark_dead(c);
1593 return -1;
1594 } else if (compat13) {
1595 buffer_clear(&c->output);
1596 c->type = SSH_CHANNEL_INPUT_DRAINING;
1597 debug2("channel %d: input draining.", c->self);
1598 } else {
1599 chan_read_failed(c);
1600 }
1601 return -1;
1602 }
1603 if (c->input_filter != NULL) {
1604 if (c->input_filter(c, buf, len) == -1) {
1605 debug2("channel %d: filter stops", c->self);
1606 chan_read_failed(c);
1607 }
1608 } else if (c->datagram) {
1609 buffer_put_string(&c->input, buf, len);
1610 } else {
1611 buffer_append(&c->input, buf, len);
1612 }
1613 }
1614 return 1;
1615 }
1616
1617 /* ARGSUSED */
1618 static int
1619 channel_handle_wfd(Channel *c, fd_set *readset, fd_set *writeset)
1620 {
1621 struct termios tio;
1622 u_char *data = NULL, *buf;
1623 u_int dlen;
1624 int len;
1625
1626 /* Send buffered output data to the socket. */
1627 if (c->wfd != -1 &&
1628 FD_ISSET(c->wfd, writeset) &&
1629 buffer_len(&c->output) > 0) {
1630 if (c->output_filter != NULL) {
1631 if ((buf = c->output_filter(c, &data, &dlen)) == NULL) {
1632 debug2("channel %d: filter stops", c->self);
1633 if (c->type != SSH_CHANNEL_OPEN)
1634 chan_mark_dead(c);
1635 else
1636 chan_write_failed(c);
1637 return -1;
1638 }
1639 } else if (c->datagram) {
1640 buf = data = buffer_get_string(&c->output, &dlen);
1641 } else {
1642 buf = data = buffer_ptr(&c->output);
1643 dlen = buffer_len(&c->output);
1644 }
1645
1646 if (c->datagram) {
1647 /* ignore truncated writes, datagrams might get lost */
1648 c->local_consumed += dlen + 4;
1649 len = write(c->wfd, buf, dlen);
1650 xfree(data);
1651 if (len < 0 && (errno == EINTR || errno == EAGAIN ||
1652 errno == EWOULDBLOCK))
1653 return 1;
1654 if (len <= 0) {
1655 if (c->type != SSH_CHANNEL_OPEN)
1656 chan_mark_dead(c);
1657 else
1658 chan_write_failed(c);
1659 return -1;
1660 }
1661 return 1;
1662 }
1663 #ifdef _AIX
1664 /* XXX: Later AIX versions can't push as much data to tty */
1665 if (compat20 && c->wfd_isatty)
1666 dlen = MIN(dlen, 8*1024);
1667 #endif
1668
1669 len = write(c->wfd, buf, dlen);
1670 if (len < 0 &&
1671 (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK))
1672 return 1;
1673 if (len <= 0) {
1674 if (c->type != SSH_CHANNEL_OPEN) {
1675 debug2("channel %d: not open", c->self);
1676 chan_mark_dead(c);
1677 return -1;
1678 } else if (compat13) {
1679 buffer_clear(&c->output);
1680 debug2("channel %d: input draining.", c->self);
1681 c->type = SSH_CHANNEL_INPUT_DRAINING;
1682 } else {
1683 chan_write_failed(c);
1684 }
1685 return -1;
1686 }
1687 #ifndef BROKEN_TCGETATTR_ICANON
1688 if (compat20 && c->isatty && dlen >= 1 && buf[0] != '\r') {
1689 if (tcgetattr(c->wfd, &tio) == 0 &&
1690 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1691 /*
1692 * Simulate echo to reduce the impact of
1693 * traffic analysis. We need to match the
1694 * size of a SSH2_MSG_CHANNEL_DATA message
1695 * (4 byte channel id + buf)
1696 */
1697 packet_send_ignore(4 + len);
1698 packet_send();
1699 }
1700 }
1701 #endif
1702 buffer_consume(&c->output, len);
1703 if (compat20 && len > 0) {
1704 c->local_consumed += len;
1705 }
1706 }
1707 return 1;
1708 }
1709
1710 static int
1711 channel_handle_efd(Channel *c, fd_set *readset, fd_set *writeset)
1712 {
1713 char buf[CHAN_RBUF];
1714 int len;
1715
1716 /** XXX handle drain efd, too */
1717 if (c->efd != -1) {
1718 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1719 FD_ISSET(c->efd, writeset) &&
1720 buffer_len(&c->extended) > 0) {
1721 len = write(c->efd, buffer_ptr(&c->extended),
1722 buffer_len(&c->extended));
1723 debug2("channel %d: written %d to efd %d",
1724 c->self, len, c->efd);
1725 if (len < 0 && (errno == EINTR || errno == EAGAIN ||
1726 errno == EWOULDBLOCK))
1727 return 1;
1728 if (len <= 0) {
1729 debug2("channel %d: closing write-efd %d",
1730 c->self, c->efd);
1731 channel_close_fd(&c->efd);
1732 } else {
1733 buffer_consume(&c->extended, len);
1734 c->local_consumed += len;
1735 }
1736 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
1737 (c->detach_close || FD_ISSET(c->efd, readset))) {
1738 len = read(c->efd, buf, sizeof(buf));
1739 debug2("channel %d: read %d from efd %d",
1740 c->self, len, c->efd);
1741 if (len < 0 && (errno == EINTR || ((errno == EAGAIN ||
1742 errno == EWOULDBLOCK) && !c->detach_close)))
1743 return 1;
1744 if (len <= 0) {
1745 debug2("channel %d: closing read-efd %d",
1746 c->self, c->efd);
1747 channel_close_fd(&c->efd);
1748 } else {
1749 buffer_append(&c->extended, buf, len);
1750 }
1751 }
1752 }
1753 return 1;
1754 }
1755
1756 /* ARGSUSED */
1757 static int
1758 channel_handle_ctl(Channel *c, fd_set *readset, fd_set *writeset)
1759 {
1760 char buf[16];
1761 int len;
1762
1763 /* Monitor control fd to detect if the slave client exits */
1764 if (c->ctl_fd != -1 && FD_ISSET(c->ctl_fd, readset)) {
1765 len = read(c->ctl_fd, buf, sizeof(buf));
1766 if (len < 0 &&
1767 (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK))
1768 return 1;
1769 if (len <= 0) {
1770 debug2("channel %d: ctl read<=0", c->self);
1771 if (c->type != SSH_CHANNEL_OPEN) {
1772 debug2("channel %d: not open", c->self);
1773 chan_mark_dead(c);
1774 return -1;
1775 } else {
1776 chan_read_failed(c);
1777 chan_write_failed(c);
1778 }
1779 return -1;
1780 } else
1781 fatal("%s: unexpected data on ctl fd", __func__);
1782 }
1783 return 1;
1784 }
1785
1786 static int
1787 channel_check_window(Channel *c)
1788 {
1789 if (c->type == SSH_CHANNEL_OPEN &&
1790 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1791 ((c->local_window_max - c->local_window >
1792 c->local_maxpacket*3) ||
1793 c->local_window < c->local_window_max/2) &&
1794 c->local_consumed > 0) {
1795 u_int addition = 0;
1796 /* adjust max window size if we are in a dynamic environment */
1797 if (c->dynamic_window && (c->tcpwinsz > c->local_window_max)) {
1798 /* grow the window somewhat aggressively to maintain pressure */
1799 addition = 1.5*(c->tcpwinsz - c->local_window_max);
1800 c->local_window_max += addition;
1801 }
1802 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1803 packet_put_int(c->remote_id);
1804 packet_put_int(c->local_consumed + addition);
1805 packet_send();
1806 debug2("channel %d: window %d sent adjust %d",
1807 c->self, c->local_window,
1808 c->local_consumed);
1809 c->local_window += c->local_consumed + addition;
1810 c->local_consumed = 0;
1811 }
1812 return 1;
1813 }
1814
1815 static void
1816 channel_post_open(Channel *c, fd_set *readset, fd_set *writeset)
1817 {
1818 if (c->delayed)
1819 return;
1820 channel_handle_rfd(c, readset, writeset);
1821 channel_handle_wfd(c, readset, writeset);
1822 if (!compat20)
1823 return;
1824 channel_handle_efd(c, readset, writeset);
1825 channel_handle_ctl(c, readset, writeset);
1826 channel_check_window(c);
1827 }
1828
1829 /* ARGSUSED */
1830 static void
1831 channel_post_output_drain_13(Channel *c, fd_set *readset, fd_set *writeset)
1832 {
1833 int len;
1834
1835 /* Send buffered output data to the socket. */
1836 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1837 len = write(c->sock, buffer_ptr(&c->output),
1838 buffer_len(&c->output));
1839 if (len <= 0)
1840 buffer_clear(&c->output);
1841 else
1842 buffer_consume(&c->output, len);
1843 }
1844 }
1845
1846 static void
1847 channel_handler_init_20(void)
1848 {
1849 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1850 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1851 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1852 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
1853 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1854 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1855 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1856 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1857
1858 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1859 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1860 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
1861 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1862 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1863 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1864 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1865 }
1866
1867 static void
1868 channel_handler_init_13(void)
1869 {
1870 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
1871 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
1872 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1873 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1874 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1875 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
1876 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1877 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1878 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1879
1880 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1881 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1882 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1883 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1884 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
1885 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1886 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1887 }
1888
1889 static void
1890 channel_handler_init_15(void)
1891 {
1892 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1893 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1894 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1895 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1896 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1897 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1898 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1899
1900 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1901 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1902 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1903 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1904 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1905 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1906 }
1907
1908 static void
1909 channel_handler_init(void)
1910 {
1911 int i;
1912
1913 for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
1914 channel_pre[i] = NULL;
1915 channel_post[i] = NULL;
1916 }
1917 if (compat20)
1918 channel_handler_init_20();
1919 else if (compat13)
1920 channel_handler_init_13();
1921 else
1922 channel_handler_init_15();
1923 }
1924
1925 /* gc dead channels */
1926 static void
1927 channel_garbage_collect(Channel *c)
1928 {
1929 if (c == NULL)
1930 return;
1931 if (c->detach_user != NULL) {
1932 if (!chan_is_dead(c, c->detach_close))
1933 return;
1934 debug2("channel %d: gc: notify user", c->self);
1935 c->detach_user(c->self, NULL);
1936 /* if we still have a callback */
1937 if (c->detach_user != NULL)
1938 return;
1939 debug2("channel %d: gc: user detached", c->self);
1940 }
1941 if (!chan_is_dead(c, 1))
1942 return;
1943 debug2("channel %d: garbage collecting", c->self);
1944 channel_free(c);
1945 }
1946
1947 static void
1948 channel_handler(chan_fn *ftab[], fd_set *readset, fd_set *writeset)
1949 {
1950 static int did_init = 0;
1951 u_int i;
1952 Channel *c;
1953
1954 if (!did_init) {
1955 channel_handler_init();
1956 did_init = 1;
1957 }
1958 for (i = 0; i < channels_alloc; i++) {
1959 c = channels[i];
1960 if (c == NULL)
1961 continue;
1962 if (ftab[c->type] != NULL)
1963 (*ftab[c->type])(c, readset, writeset);
1964 channel_garbage_collect(c);
1965 }
1966 }
1967
1968 /*
1969 * Allocate/update select bitmasks and add any bits relevant to channels in
1970 * select bitmasks.
1971 */
1972 void
1973 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
1974 u_int *nallocp, int rekeying)
1975 {
1976 u_int n, sz, nfdset;
1977
1978 n = MAX(*maxfdp, channel_max_fd);
1979
1980 nfdset = howmany(n+1, NFDBITS);
1981 /* Explicitly test here, because xrealloc isn't always called */
1982 if (nfdset && SIZE_T_MAX / nfdset < sizeof(fd_mask))
1983 fatal("channel_prepare_select: max_fd (%d) is too large", n);
1984 sz = nfdset * sizeof(fd_mask);
1985
1986 /* perhaps check sz < nalloc/2 and shrink? */
1987 if (*readsetp == NULL || sz > *nallocp) {
1988 *readsetp = xrealloc(*readsetp, nfdset, sizeof(fd_mask));
1989 *writesetp = xrealloc(*writesetp, nfdset, sizeof(fd_mask));
1990 *nallocp = sz;
1991 }
1992 *maxfdp = n;
1993 memset(*readsetp, 0, sz);
1994 memset(*writesetp, 0, sz);
1995
1996 if (!rekeying)
1997 channel_handler(channel_pre, *readsetp, *writesetp);
1998 }
1999
2000 /*
2001 * After select, perform any appropriate operations for channels which have
2002 * events pending.
2003 */
2004 void
2005 channel_after_select(fd_set *readset, fd_set *writeset)
2006 {
2007 channel_handler(channel_post, readset, writeset);
2008 }
2009
2010
2011 /* If there is data to send to the connection, enqueue some of it now. */
2012 int
2013 channel_output_poll(void)
2014 {
2015 Channel *c;
2016 u_int i, len;
2017 int packet_length = 0;
2018
2019 for (i = 0; i < channels_alloc; i++) {
2020 c = channels[i];
2021 if (c == NULL)
2022 continue;
2023
2024 /*
2025 * We are only interested in channels that can have buffered
2026 * incoming data.
2027 */
2028 if (compat13) {
2029 if (c->type != SSH_CHANNEL_OPEN &&
2030 c->type != SSH_CHANNEL_INPUT_DRAINING)
2031 continue;
2032 } else {
2033 if (c->type != SSH_CHANNEL_OPEN)
2034 continue;
2035 }
2036 if (compat20 &&
2037 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
2038 /* XXX is this true? */
2039 debug3("channel %d: will not send data after close", c->self);
2040 continue;
2041 }
2042
2043 /* Get the amount of buffered data for this channel. */
2044 if ((c->istate == CHAN_INPUT_OPEN ||
2045 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
2046 (len = buffer_len(&c->input)) > 0) {
2047 if (c->datagram) {
2048 if (len > 0) {
2049 u_char *data;
2050 u_int dlen;
2051
2052 data = buffer_get_string(&c->input,
2053 &dlen);
2054 packet_start(SSH2_MSG_CHANNEL_DATA);
2055 packet_put_int(c->remote_id);
2056 packet_put_string(data, dlen);
2057 packet_length = packet_send();
2058 c->remote_window -= dlen + 4;
2059 xfree(data);
2060 }
2061 continue;
2062 }
2063 /*
2064 * Send some data for the other side over the secure
2065 * connection.
2066 */
2067 if (compat20) {
2068 if (len > c->remote_window)
2069 len = c->remote_window;
2070 if (len > c->remote_maxpacket)
2071 len = c->remote_maxpacket;
2072 } else {
2073 if (packet_is_interactive()) {
2074 if (len > 1024)
2075 len = 512;
2076 } else {
2077 /* Keep the packets at reasonable size. */
2078 if (len > packet_get_maxsize()/2)
2079 len = packet_get_maxsize()/2;
2080 }
2081 }
2082 if (len > 0) {
2083 packet_start(compat20 ?
2084 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
2085 packet_put_int(c->remote_id);
2086 packet_put_string(buffer_ptr(&c->input), len);
2087 packet_length = packet_send();
2088 buffer_consume(&c->input, len);
2089 c->remote_window -= len;
2090 }
2091 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
2092 if (compat13)
2093 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
2094 /*
2095 * input-buffer is empty and read-socket shutdown:
2096 * tell peer, that we will not send more data: send IEOF.
2097 * hack for extended data: delay EOF if EFD still in use.
2098 */
2099 if (CHANNEL_EFD_INPUT_ACTIVE(c))
2100 debug2("channel %d: ibuf_empty delayed efd %d/(%d)",
2101 c->self, c->efd, buffer_len(&c->extended));
2102 else
2103 chan_ibuf_empty(c);
2104 }
2105 /* Send extended data, i.e. stderr */
2106 if (compat20 &&
2107 !(c->flags & CHAN_EOF_SENT) &&
2108 c->remote_window > 0 &&
2109 (len = buffer_len(&c->extended)) > 0 &&
2110 c->extended_usage == CHAN_EXTENDED_READ) {
2111 debug2("channel %d: rwin %u elen %u euse %d",
2112 c->self, c->remote_window, buffer_len(&c->extended),
2113 c->extended_usage);
2114 if (len > c->remote_window)
2115 len = c->remote_window;
2116 if (len > c->remote_maxpacket)
2117 len = c->remote_maxpacket;
2118 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
2119 packet_put_int(c->remote_id);
2120 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
2121 packet_put_string(buffer_ptr(&c->extended), len);
2122 packet_length = packet_send();
2123 buffer_consume(&c->extended, len);
2124 c->remote_window -= len;
2125 debug2("channel %d: sent ext data %d", c->self, len);
2126 }
2127 }
2128 return (packet_length);
2129 }
2130
2131
2132 /* -- protocol input */
2133
2134 /* ARGSUSED */
2135 void
2136 channel_input_data(int type, u_int32_t seq, void *ctxt)
2137 {
2138 int id;
2139 char *data;
2140 u_int data_len;
2141 Channel *c;
2142
2143 /* Get the channel number and verify it. */
2144 id = packet_get_int();
2145 c = channel_lookup(id);
2146 if (c == NULL)
2147 packet_disconnect("Received data for nonexistent channel %d.", id);
2148
2149 /* Ignore any data for non-open channels (might happen on close) */
2150 if (c->type != SSH_CHANNEL_OPEN &&
2151 c->type != SSH_CHANNEL_X11_OPEN)
2152 return;
2153
2154 /* Get the data. */
2155 data = packet_get_string_ptr(&data_len);
2156
2157 /*
2158 * Ignore data for protocol > 1.3 if output end is no longer open.
2159 * For protocol 2 the sending side is reducing its window as it sends
2160 * data, so we must 'fake' consumption of the data in order to ensure
2161 * that window updates are sent back. Otherwise the connection might
2162 * deadlock.
2163 */
2164 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) {
2165 if (compat20) {
2166 c->local_window -= data_len;
2167 c->local_consumed += data_len;
2168 }
2169 return;
2170 }
2171
2172 if (compat20) {
2173 if (data_len > c->local_maxpacket) {
2174 logit("channel %d: rcvd big packet %d, maxpack %d",
2175 c->self, data_len, c->local_maxpacket);
2176 }
2177 if (data_len > c->local_window) {
2178 logit("channel %d: rcvd too much data %d, win %d",
2179 c->self, data_len, c->local_window);
2180 return;
2181 }
2182 c->local_window -= data_len;
2183 }
2184 if (c->datagram)
2185 buffer_put_string(&c->output, data, data_len);
2186 else
2187 buffer_append(&c->output, data, data_len);
2188 packet_check_eom();
2189 }
2190
2191 /* ARGSUSED */
2192 void
2193 channel_input_extended_data(int type, u_int32_t seq, void *ctxt)
2194 {
2195 int id;
2196 char *data;
2197 u_int data_len, tcode;
2198 Channel *c;
2199
2200 /* Get the channel number and verify it. */
2201 id = packet_get_int();
2202 c = channel_lookup(id);
2203
2204 if (c == NULL)
2205 packet_disconnect("Received extended_data for bad channel %d.", id);
2206 if (c->type != SSH_CHANNEL_OPEN) {
2207 logit("channel %d: ext data for non open", id);
2208 return;
2209 }
2210 if (c->flags & CHAN_EOF_RCVD) {
2211 if (datafellows & SSH_BUG_EXTEOF)
2212 debug("channel %d: accepting ext data after eof", id);
2213 else
2214 packet_disconnect("Received extended_data after EOF "
2215 "on channel %d.", id);
2216 }
2217 tcode = packet_get_int();
2218 if (c->efd == -1 ||
2219 c->extended_usage != CHAN_EXTENDED_WRITE ||
2220 tcode != SSH2_EXTENDED_DATA_STDERR) {
2221 logit("channel %d: bad ext data", c->self);
2222 return;
2223 }
2224 data = packet_get_string(&data_len);
2225 packet_check_eom();
2226 if (data_len > c->local_window) {
2227 logit("channel %d: rcvd too much extended_data %d, win %d",
2228 c->self, data_len, c->local_window);
2229 xfree(data);
2230 return;
2231 }
2232 debug2("channel %d: rcvd ext data %d", c->self, data_len);
2233 c->local_window -= data_len;
2234 buffer_append(&c->extended, data, data_len);
2235 xfree(data);
2236 }
2237
2238 /* ARGSUSED */
2239 void
2240 channel_input_ieof(int type, u_int32_t seq, void *ctxt)
2241 {
2242 int id;
2243 Channel *c;
2244
2245 id = packet_get_int();
2246 packet_check_eom();
2247 c = channel_lookup(id);
2248 if (c == NULL)
2249 packet_disconnect("Received ieof for nonexistent channel %d.", id);
2250 chan_rcvd_ieof(c);
2251
2252 /* XXX force input close */
2253 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) {
2254 debug("channel %d: FORCE input drain", c->self);
2255 c->istate = CHAN_INPUT_WAIT_DRAIN;
2256 if (buffer_len(&c->input) == 0)
2257 chan_ibuf_empty(c);
2258 }
2259
2260 }
2261
2262 /* ARGSUSED */
2263 void
2264 channel_input_close(int type, u_int32_t seq, void *ctxt)
2265 {
2266 int id;
2267 Channel *c;
2268
2269 id = packet_get_int();
2270 packet_check_eom();
2271 c = channel_lookup(id);
2272 if (c == NULL)
2273 packet_disconnect("Received close for nonexistent channel %d.", id);
2274
2275 /*
2276 * Send a confirmation that we have closed the channel and no more
2277 * data is coming for it.
2278 */
2279 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
2280 packet_put_int(c->remote_id);
2281 packet_send();
2282
2283 /*
2284 * If the channel is in closed state, we have sent a close request,
2285 * and the other side will eventually respond with a confirmation.
2286 * Thus, we cannot free the channel here, because then there would be
2287 * no-one to receive the confirmation. The channel gets freed when
2288 * the confirmation arrives.
2289 */
2290 if (c->type != SSH_CHANNEL_CLOSED) {
2291 /*
2292 * Not a closed channel - mark it as draining, which will
2293 * cause it to be freed later.
2294 */
2295 buffer_clear(&c->input);
2296 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
2297 }
2298 }
2299
2300 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
2301 /* ARGSUSED */
2302 void
2303 channel_input_oclose(int type, u_int32_t seq, void *ctxt)
2304 {
2305 int id = packet_get_int();
2306 Channel *c = channel_lookup(id);
2307
2308 packet_check_eom();
2309 if (c == NULL)
2310 packet_disconnect("Received oclose for nonexistent channel %d.", id);
2311 chan_rcvd_oclose(c);
2312 }
2313
2314 /* ARGSUSED */
2315 void
2316 channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt)
2317 {
2318 int id = packet_get_int();
2319 Channel *c = channel_lookup(id);
2320
2321 packet_check_eom();
2322 if (c == NULL)
2323 packet_disconnect("Received close confirmation for "
2324 "out-of-range channel %d.", id);
2325 if (c->type != SSH_CHANNEL_CLOSED)
2326 packet_disconnect("Received close confirmation for "
2327 "non-closed channel %d (type %d).", id, c->type);
2328 channel_free(c);
2329 }
2330
2331 /* ARGSUSED */
2332 void
2333 channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt)
2334 {
2335 int id, remote_id;
2336 Channel *c;
2337
2338 id = packet_get_int();
2339 c = channel_lookup(id);
2340
2341 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2342 packet_disconnect("Received open confirmation for "
2343 "non-opening channel %d.", id);
2344 remote_id = packet_get_int();
2345 /* Record the remote channel number and mark that the channel is now open. */
2346 c->remote_id = remote_id;
2347 c->type = SSH_CHANNEL_OPEN;
2348
2349 if (compat20) {
2350 c->remote_window = packet_get_int();
2351 c->remote_maxpacket = packet_get_int();
2352 if (c->open_confirm) {
2353 debug2("callback start");
2354 c->open_confirm(c->self, c->open_confirm_ctx);
2355 debug2("callback done");
2356 }
2357 debug2("channel %d: open confirm rwindow %u rmax %u", c->self,
2358 c->remote_window, c->remote_maxpacket);
2359 }
2360 packet_check_eom();
2361 }
2362
2363 static char *
2364 reason2txt(int reason)
2365 {
2366 switch (reason) {
2367 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
2368 return "administratively prohibited";
2369 case SSH2_OPEN_CONNECT_FAILED:
2370 return "connect failed";
2371 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
2372 return "unknown channel type";
2373 case SSH2_OPEN_RESOURCE_SHORTAGE:
2374 return "resource shortage";
2375 }
2376 return "unknown reason";
2377 }
2378
2379 /* ARGSUSED */
2380 void
2381 channel_input_open_failure(int type, u_int32_t seq, void *ctxt)
2382 {
2383 int id, reason;
2384 char *msg = NULL, *lang = NULL;
2385 Channel *c;
2386
2387 id = packet_get_int();
2388 c = channel_lookup(id);
2389
2390 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2391 packet_disconnect("Received open failure for "
2392 "non-opening channel %d.", id);
2393 if (compat20) {
2394 reason = packet_get_int();
2395 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
2396 msg = packet_get_string(NULL);
2397 lang = packet_get_string(NULL);
2398 }
2399 logit("channel %d: open failed: %s%s%s", id,
2400 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
2401 if (msg != NULL)
2402 xfree(msg);
2403 if (lang != NULL)
2404 xfree(lang);
2405 }
2406 packet_check_eom();
2407 /* Schedule the channel for cleanup/deletion. */
2408 chan_mark_dead(c);
2409 }
2410
2411 /* ARGSUSED */
2412 void
2413 channel_input_window_adjust(int type, u_int32_t seq, void *ctxt)
2414 {
2415 Channel *c;
2416 int id;
2417 u_int adjust;
2418
2419 if (!compat20)
2420 return;
2421
2422 /* Get the channel number and verify it. */
2423 id = packet_get_int();
2424 c = channel_lookup(id);
2425
2426 if (c == NULL) {
2427 logit("Received window adjust for non-open channel %d.", id);
2428 return;
2429 }
2430 adjust = packet_get_int();
2431 packet_check_eom();
2432 debug2("channel %d: rcvd adjust %u", id, adjust);
2433 c->remote_window += adjust;
2434 }
2435
2436 /* ARGSUSED */
2437 void
2438 channel_input_port_open(int type, u_int32_t seq, void *ctxt)
2439 {
2440 Channel *c = NULL;
2441 u_short host_port;
2442 char *host, *originator_string;
2443 int remote_id;
2444
2445 remote_id = packet_get_int();
2446 host = packet_get_string(NULL);
2447 host_port = packet_get_int();
2448
2449 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2450 originator_string = packet_get_string(NULL);
2451 } else {
2452 originator_string = xstrdup("unknown (remote did not supply name)");
2453 }
2454 packet_check_eom();
2455 c = channel_connect_to(host, host_port,
2456 "connected socket", originator_string);
2457 xfree(originator_string);
2458 xfree(host);
2459 if (c == NULL) {
2460 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2461 packet_put_int(remote_id);
2462 packet_send();
2463 } else
2464 c->remote_id = remote_id;
2465 }
2466
2467 /* ARGSUSED */
2468 void
2469 channel_input_status_confirm(int type, u_int32_t seq, void *ctxt)
2470 {
2471 Channel *c;
2472 struct channel_confirm *cc;
2473 int id;
2474
2475 /* Reset keepalive timeout */
2476 packet_set_alive_timeouts(0);
2477
2478 id = packet_get_int();
2479 packet_check_eom();
2480
2481 debug2("channel_input_status_confirm: type %d id %d", type, id);
2482
2483 if ((c = channel_lookup(id)) == NULL) {
2484 logit("channel_input_status_confirm: %d: unknown", id);
2485 return;
2486 }
2487 ;
2488 if ((cc = TAILQ_FIRST(&c->status_confirms)) == NULL)
2489 return;
2490 cc->cb(type, c, cc->ctx);
2491 TAILQ_REMOVE(&c->status_confirms, cc, entry);
2492 bzero(cc, sizeof(*cc));
2493 xfree(cc);
2494 }
2495
2496 /* -- tcp forwarding */
2497
2498 void
2499 channel_set_af(int af)
2500 {
2501 IPv4or6 = af;
2502 }
2503
2504
2505 void
2506 channel_set_hpn(int external_hpn_disabled, int external_hpn_buffer_size)
2507 {
2508 hpn_disabled = external_hpn_disabled;
2509 hpn_buffer_size = external_hpn_buffer_size;
2510 debug("HPN Disabled: %d, HPN Buffer Size: %d", hpn_disabled, hpn_buffer_size);
2511 }
2512
2513 static int
2514 channel_setup_fwd_listener(int type, const char *listen_addr,
2515 u_short listen_port, int *allocated_listen_port,
2516 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2517 {
2518 Channel *c;
2519 int sock, r, success = 0, wildcard = 0, is_client;
2520 struct addrinfo hints, *ai, *aitop;
2521 const char *host, *addr;
2522 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2523 in_port_t *lport_p;
2524
2525 host = (type == SSH_CHANNEL_RPORT_LISTENER) ?
2526 listen_addr : host_to_connect;
2527 is_client = (type == SSH_CHANNEL_PORT_LISTENER);
2528
2529 if (host == NULL) {
2530 error("No forward host name.");
2531 return 0;
2532 }
2533 if (strlen(host) >= NI_MAXHOST) {
2534 error("Forward host name too long.");
2535 return 0;
2536 }
2537
2538 /*
2539 * Determine whether or not a port forward listens to loopback,
2540 * specified address or wildcard. On the client, a specified bind
2541 * address will always override gateway_ports. On the server, a
2542 * gateway_ports of 1 (``yes'') will override the client's
2543 * specification and force a wildcard bind, whereas a value of 2
2544 * (``clientspecified'') will bind to whatever address the client
2545 * asked for.
2546 *
2547 * Special-case listen_addrs are:
2548 *
2549 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR
2550 * "" (empty string), "*" -> wildcard v4/v6
2551 * "localhost" -> loopback v4/v6
2552 */
2553 addr = NULL;
2554 if (listen_addr == NULL) {
2555 /* No address specified: default to gateway_ports setting */
2556 if (gateway_ports)
2557 wildcard = 1;
2558 } else if (gateway_ports || is_client) {
2559 if (((datafellows & SSH_OLD_FORWARD_ADDR) &&
2560 strcmp(listen_addr, "0.0.0.0") == 0 && is_client == 0) ||
2561 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 ||
2562 (!is_client && gateway_ports == 1))
2563 wildcard = 1;
2564 else if (strcmp(listen_addr, "localhost") != 0)
2565 addr = listen_addr;
2566 }
2567
2568 debug3("channel_setup_fwd_listener: type %d wildcard %d addr %s",
2569 type, wildcard, (addr == NULL) ? "NULL" : addr);
2570
2571 /*
2572 * getaddrinfo returns a loopback address if the hostname is
2573 * set to NULL and hints.ai_flags is not AI_PASSIVE
2574 */
2575 memset(&hints, 0, sizeof(hints));
2576 hints.ai_family = IPv4or6;
2577 hints.ai_flags = wildcard ? AI_PASSIVE : 0;
2578 hints.ai_socktype = SOCK_STREAM;
2579 snprintf(strport, sizeof strport, "%d", listen_port);
2580 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) {
2581 if (addr == NULL) {
2582 /* This really shouldn't happen */
2583 packet_disconnect("getaddrinfo: fatal error: %s",
2584 ssh_gai_strerror(r));
2585 } else {
2586 error("channel_setup_fwd_listener: "
2587 "getaddrinfo(%.64s): %s", addr,
2588 ssh_gai_strerror(r));
2589 }
2590 return 0;
2591 }
2592 if (allocated_listen_port != NULL)
2593 *allocated_listen_port = 0;
2594 for (ai = aitop; ai; ai = ai->ai_next) {
2595 switch (ai->ai_family) {
2596 case AF_INET:
2597 lport_p = &((struct sockaddr_in *)ai->ai_addr)->
2598 sin_port;
2599 break;
2600 case AF_INET6:
2601 lport_p = &((struct sockaddr_in6 *)ai->ai_addr)->
2602 sin6_port;
2603 break;
2604 default:
2605 continue;
2606 }
2607 /*
2608 * If allocating a port for -R forwards, then use the
2609 * same port for all address families.
2610 */
2611 if (type == SSH_CHANNEL_RPORT_LISTENER && listen_port == 0 &&
2612 allocated_listen_port != NULL && *allocated_listen_port > 0)
2613 *lport_p = htons(*allocated_listen_port);
2614
2615 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2616 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2617 error("channel_setup_fwd_listener: getnameinfo failed");
2618 continue;
2619 }
2620 /* Create a port to listen for the host. */
2621 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2622 if (sock < 0) {
2623 /* this is no error since kernel may not support ipv6 */
2624 verbose("socket: %.100s", strerror(errno));
2625 continue;
2626 }
2627
2628 channel_set_reuseaddr(sock);
2629
2630 debug("Local forwarding listening on %s port %s.",
2631 ntop, strport);
2632
2633 /* Bind the socket to the address. */
2634 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2635 /* address can be in use ipv6 address is already bound */
2636 if (!ai->ai_next)
2637 error("bind: %.100s", strerror(errno));
2638 else
2639 verbose("bind: %.100s", strerror(errno));
2640
2641 close(sock);
2642 continue;
2643 }
2644 /* Start listening for connections on the socket. */
2645 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2646 error("listen: %.100s", strerror(errno));
2647 close(sock);
2648 continue;
2649 }
2650
2651 /*
2652 * listen_port == 0 requests a dynamically allocated port -
2653 * record what we got.
2654 */
2655 if (type == SSH_CHANNEL_RPORT_LISTENER && listen_port == 0 &&
2656 allocated_listen_port != NULL &&
2657 *allocated_listen_port == 0) {
2658 *allocated_listen_port = get_sock_port(sock, 1);
2659 debug("Allocated listen port %d",
2660 *allocated_listen_port);
2661 }
2662
2663 /* Allocate a channel number for the socket. */
2664 /* explicitly test for hpn disabled option. if true use smaller window size */
2665 if (hpn_disabled)
2666 c = channel_new("port listener", type, sock, sock, -1,
2667 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2668 0, "port listener", 1);
2669 else
2670 c = channel_new("port listener", type, sock, sock, -1,
2671 hpn_buffer_size, CHAN_TCP_PACKET_DEFAULT,
2672 0, "port listener", 1);
2673 c->path = xstrdup(host);
2674 c->host_port = port_to_connect;
2675 c->listening_port = listen_port;
2676 success = 1;
2677 }
2678 if (success == 0)
2679 error("channel_setup_fwd_listener: cannot listen to port: %d",
2680 listen_port);
2681 freeaddrinfo(aitop);
2682 return success;
2683 }
2684
2685 int
2686 channel_cancel_rport_listener(const char *host, u_short port)
2687 {
2688 u_int i;
2689 int found = 0;
2690
2691 for (i = 0; i < channels_alloc; i++) {
2692 Channel *c = channels[i];
2693
2694 if (c != NULL && c->type == SSH_CHANNEL_RPORT_LISTENER &&
2695 strcmp(c->path, host) == 0 && c->listening_port == port) {
2696 debug2("%s: close channel %d", __func__, i);
2697 channel_free(c);
2698 found = 1;
2699 }
2700 }
2701
2702 return (found);
2703 }
2704
2705 /* protocol local port fwd, used by ssh (and sshd in v1) */
2706 int
2707 channel_setup_local_fwd_listener(const char *listen_host, u_short listen_port,
2708 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2709 {
2710 return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER,
2711 listen_host, listen_port, NULL, host_to_connect, port_to_connect,
2712 gateway_ports);
2713 }
2714
2715 /* protocol v2 remote port fwd, used by sshd */
2716 int
2717 channel_setup_remote_fwd_listener(const char *listen_address,
2718 u_short listen_port, int *allocated_listen_port, int gateway_ports)
2719 {
2720 return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER,
2721 listen_address, listen_port, allocated_listen_port,
2722 NULL, 0, gateway_ports);
2723 }
2724
2725 /*
2726 * Initiate forwarding of connections to port "port" on remote host through
2727 * the secure channel to host:port from local side.
2728 */
2729
2730 int
2731 channel_request_remote_forwarding(const char *listen_host, u_short listen_port,
2732 const char *host_to_connect, u_short port_to_connect)
2733 {
2734 int type, success = 0;
2735
2736 /* Record locally that connection to this host/port is permitted. */
2737 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2738 fatal("channel_request_remote_forwarding: too many forwards");
2739
2740 /* Send the forward request to the remote side. */
2741 if (compat20) {
2742 const char *address_to_bind;
2743 if (listen_host == NULL) {
2744 if (datafellows & SSH_BUG_RFWD_ADDR)
2745 address_to_bind = "127.0.0.1";
2746 else
2747 address_to_bind = "localhost";
2748 } else if (*listen_host == '\0' ||
2749 strcmp(listen_host, "*") == 0) {
2750 if (datafellows & SSH_BUG_RFWD_ADDR)
2751 address_to_bind = "0.0.0.0";
2752 else
2753 address_to_bind = "";
2754 } else
2755 address_to_bind = listen_host;
2756
2757 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2758 packet_put_cstring("tcpip-forward");
2759 packet_put_char(1); /* boolean: want reply */
2760 packet_put_cstring(address_to_bind);
2761 packet_put_int(listen_port);
2762 packet_send();
2763 packet_write_wait();
2764 /* Assume that server accepts the request */
2765 success = 1;
2766 } else {
2767 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2768 packet_put_int(listen_port);
2769 packet_put_cstring(host_to_connect);
2770 packet_put_int(port_to_connect);
2771 packet_send();
2772 packet_write_wait();
2773
2774 /* Wait for response from the remote side. */
2775 type = packet_read();
2776 switch (type) {
2777 case SSH_SMSG_SUCCESS:
2778 success = 1;
2779 break;
2780 case SSH_SMSG_FAILURE:
2781 break;
2782 default:
2783 /* Unknown packet */
2784 packet_disconnect("Protocol error for port forward request:"
2785 "received packet type %d.", type);
2786 }
2787 }
2788 if (success) {
2789 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2790 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2791 permitted_opens[num_permitted_opens].listen_port = listen_port;
2792 num_permitted_opens++;
2793 }
2794 return (success ? 0 : -1);
2795 }
2796
2797 /*
2798 * Request cancellation of remote forwarding of connection host:port from
2799 * local side.
2800 */
2801 void
2802 channel_request_rforward_cancel(const char *host, u_short port)
2803 {
2804 int i;
2805
2806 if (!compat20)
2807 return;
2808
2809 for (i = 0; i < num_permitted_opens; i++) {
2810 if (permitted_opens[i].host_to_connect != NULL &&
2811 permitted_opens[i].listen_port == port)
2812 break;
2813 }
2814 if (i >= num_permitted_opens) {
2815 debug("%s: requested forward not found", __func__);
2816 return;
2817 }
2818 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2819 packet_put_cstring("cancel-tcpip-forward");
2820 packet_put_char(0);
2821 packet_put_cstring(host == NULL ? "" : host);
2822 packet_put_int(port);
2823 packet_send();
2824
2825 permitted_opens[i].listen_port = 0;
2826 permitted_opens[i].port_to_connect = 0;
2827 xfree(permitted_opens[i].host_to_connect);
2828 permitted_opens[i].host_to_connect = NULL;
2829 }
2830
2831 /*
2832 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
2833 * listening for the port, and sends back a success reply (or disconnect
2834 * message if there was an error).
2835 */
2836 int
2837 channel_input_port_forward_request(int is_root, int gateway_ports)
2838 {
2839 u_short port, host_port;
2840 int success = 0;
2841 char *hostname;
2842
2843 /* Get arguments from the packet. */
2844 port = packet_get_int();
2845 hostname = packet_get_string(NULL);
2846 host_port = packet_get_int();
2847
2848 #ifndef HAVE_CYGWIN
2849 /*
2850 * Check that an unprivileged user is not trying to forward a
2851 * privileged port.
2852 */
2853 if (port < IPPORT_RESERVED && !is_root)
2854 packet_disconnect(
2855 "Requested forwarding of port %d but user is not root.",
2856 port);
2857 if (host_port == 0)
2858 packet_disconnect("Dynamic forwarding denied.");
2859 #endif
2860
2861 /* Initiate forwarding */
2862 success = channel_setup_local_fwd_listener(NULL, port, hostname,
2863 host_port, gateway_ports);
2864
2865 /* Free the argument string. */
2866 xfree(hostname);
2867
2868 return (success ? 0 : -1);
2869 }
2870
2871 /*
2872 * Permits opening to any host/port if permitted_opens[] is empty. This is
2873 * usually called by the server, because the user could connect to any port
2874 * anyway, and the server has no way to know but to trust the client anyway.
2875 */
2876 void
2877 channel_permit_all_opens(void)
2878 {
2879 if (num_permitted_opens == 0)
2880 all_opens_permitted = 1;
2881 }
2882
2883 void
2884 channel_add_permitted_opens(char *host, int port)
2885 {
2886 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2887 fatal("channel_add_permitted_opens: too many forwards");
2888 debug("allow port forwarding to host %s port %d", host, port);
2889
2890 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
2891 permitted_opens[num_permitted_opens].port_to_connect = port;
2892 num_permitted_opens++;
2893
2894 all_opens_permitted = 0;
2895 }
2896
2897 int
2898 channel_add_adm_permitted_opens(char *host, int port)
2899 {
2900 if (num_adm_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2901 fatal("channel_add_adm_permitted_opens: too many forwards");
2902 debug("config allows port forwarding to host %s port %d", host, port);
2903
2904 permitted_adm_opens[num_adm_permitted_opens].host_to_connect
2905 = xstrdup(host);
2906 permitted_adm_opens[num_adm_permitted_opens].port_to_connect = port;
2907 return ++num_adm_permitted_opens;
2908 }
2909
2910 void
2911 channel_clear_permitted_opens(void)
2912 {
2913 int i;
2914
2915 for (i = 0; i < num_permitted_opens; i++)
2916 if (permitted_opens[i].host_to_connect != NULL)
2917 xfree(permitted_opens[i].host_to_connect);
2918 num_permitted_opens = 0;
2919 }
2920
2921 void
2922 channel_clear_adm_permitted_opens(void)
2923 {
2924 int i;
2925
2926 for (i = 0; i < num_adm_permitted_opens; i++)
2927 if (permitted_adm_opens[i].host_to_connect != NULL)
2928 xfree(permitted_adm_opens[i].host_to_connect);
2929 num_adm_permitted_opens = 0;
2930 }
2931
2932 void
2933 channel_print_adm_permitted_opens(void)
2934 {
2935 int i;
2936
2937 printf("permitopen");
2938 if (num_adm_permitted_opens == 0) {
2939 printf(" any\n");
2940 return;
2941 }
2942 for (i = 0; i < num_adm_permitted_opens; i++)
2943 if (permitted_adm_opens[i].host_to_connect != NULL)
2944 printf(" %s:%d", permitted_adm_opens[i].host_to_connect,
2945 permitted_adm_opens[i].port_to_connect);
2946 printf("\n");
2947 }
2948
2949 /* Try to start non-blocking connect to next host in cctx list */
2950 static int
2951 connect_next(struct channel_connect *cctx)
2952 {
2953 int sock, saved_errno;
2954 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2955
2956 for (; cctx->ai; cctx->ai = cctx->ai->ai_next) {
2957 if (cctx->ai->ai_family != AF_INET &&
2958 cctx->ai->ai_family != AF_INET6)
2959 continue;
2960 if (getnameinfo(cctx->ai->ai_addr, cctx->ai->ai_addrlen,
2961 ntop, sizeof(ntop), strport, sizeof(strport),
2962 NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2963 error("connect_next: getnameinfo failed");
2964 continue;
2965 }
2966 if ((sock = socket(cctx->ai->ai_family, cctx->ai->ai_socktype,
2967 cctx->ai->ai_protocol)) == -1) {
2968 if (cctx->ai->ai_next == NULL)
2969 error("socket: %.100s", strerror(errno));
2970 else
2971 verbose("socket: %.100s", strerror(errno));
2972 continue;
2973 }
2974 if (set_nonblock(sock) == -1)
2975 fatal("%s: set_nonblock(%d)", __func__, sock);
2976 if (connect(sock, cctx->ai->ai_addr,
2977 cctx->ai->ai_addrlen) == -1 && errno != EINPROGRESS) {
2978 debug("connect_next: host %.100s ([%.100s]:%s): "
2979 "%.100s", cctx->host, ntop, strport,
2980 strerror(errno));
2981 saved_errno = errno;
2982 close(sock);
2983 errno = saved_errno;
2984 continue; /* fail -- try next */
2985 }
2986 debug("connect_next: host %.100s ([%.100s]:%s) "
2987 "in progress, fd=%d", cctx->host, ntop, strport, sock);
2988 cctx->ai = cctx->ai->ai_next;
2989 set_nodelay(sock);
2990 return sock;
2991 }
2992 return -1;
2993 }
2994
2995 static void
2996 channel_connect_ctx_free(struct channel_connect *cctx)
2997 {
2998 xfree(cctx->host);
2999 if (cctx->aitop)
3000 freeaddrinfo(cctx->aitop);
3001 bzero(cctx, sizeof(*cctx));
3002 cctx->host = NULL;
3003 cctx->ai = cctx->aitop = NULL;
3004 }
3005
3006 /* Return CONNECTING channel to remote host, port */
3007 static Channel *
3008 connect_to(const char *host, u_short port, char *ctype, char *rname)
3009 {
3010 struct addrinfo hints;
3011 int gaierr;
3012 int sock = -1;
3013 char strport[NI_MAXSERV];
3014 struct channel_connect cctx;
3015 Channel *c;
3016
3017 memset(&cctx, 0, sizeof(cctx));
3018 memset(&hints, 0, sizeof(hints));
3019 hints.ai_family = IPv4or6;
3020 hints.ai_socktype = SOCK_STREAM;
3021 snprintf(strport, sizeof strport, "%d", port);
3022 if ((gaierr = getaddrinfo(host, strport, &hints, &cctx.aitop)) != 0) {
3023 error("connect_to %.100s: unknown host (%s)", host,
3024 ssh_gai_strerror(gaierr));
3025 return NULL;
3026 }
3027
3028 cctx.host = xstrdup(host);
3029 cctx.port = port;
3030 cctx.ai = cctx.aitop;
3031
3032 if ((sock = connect_next(&cctx)) == -1) {
3033 error("connect to %.100s port %d failed: %s",
3034 host, port, strerror(errno));
3035 channel_connect_ctx_free(&cctx);
3036 return NULL;
3037 }
3038 c = channel_new(ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1,
3039 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1);
3040 c->connect_ctx = cctx;
3041 return c;
3042 }
3043
3044 Channel *
3045 channel_connect_by_listen_address(u_short listen_port, char *ctype, char *rname)
3046 {
3047 int i;
3048
3049 for (i = 0; i < num_permitted_opens; i++) {
3050 if (permitted_opens[i].host_to_connect != NULL &&
3051 permitted_opens[i].listen_port == listen_port) {
3052 return connect_to(
3053 permitted_opens[i].host_to_connect,
3054 permitted_opens[i].port_to_connect, ctype, rname);
3055 }
3056 }
3057 error("WARNING: Server requests forwarding for unknown listen_port %d",
3058 listen_port);
3059 return NULL;
3060 }
3061
3062 /* Check if connecting to that port is permitted and connect. */
3063 Channel *
3064 channel_connect_to(const char *host, u_short port, char *ctype, char *rname)
3065 {
3066 int i, permit, permit_adm = 1;
3067
3068 permit = all_opens_permitted;
3069 if (!permit) {
3070 for (i = 0; i < num_permitted_opens; i++)
3071 if (permitted_opens[i].host_to_connect != NULL &&
3072 permitted_opens[i].port_to_connect == port &&
3073 strcmp(permitted_opens[i].host_to_connect, host) == 0)
3074 permit = 1;
3075 }
3076
3077 if (num_adm_permitted_opens > 0) {
3078 permit_adm = 0;
3079 for (i = 0; i < num_adm_permitted_opens; i++)
3080 if (permitted_adm_opens[i].host_to_connect != NULL &&
3081 permitted_adm_opens[i].port_to_connect == port &&
3082 strcmp(permitted_adm_opens[i].host_to_connect, host)
3083 == 0)
3084 permit_adm = 1;
3085 }
3086
3087 if (!permit || !permit_adm) {
3088 logit("Received request to connect to host %.100s port %d, "
3089 "but the request was denied.", host, port);
3090 return NULL;
3091 }
3092 return connect_to(host, port, ctype, rname);
3093 }
3094
3095 void
3096 channel_send_window_changes(void)
3097 {
3098 u_int i;
3099 struct winsize ws;
3100
3101 for (i = 0; i < channels_alloc; i++) {
3102 if (channels[i] == NULL || !channels[i]->client_tty ||
3103 channels[i]->type != SSH_CHANNEL_OPEN)
3104 continue;
3105 if (ioctl(channels[i]->rfd, TIOCGWINSZ, &ws) < 0)
3106 continue;
3107 channel_request_start(i, "window-change", 0);
3108 packet_put_int((u_int)ws.ws_col);
3109 packet_put_int((u_int)ws.ws_row);
3110 packet_put_int((u_int)ws.ws_xpixel);
3111 packet_put_int((u_int)ws.ws_ypixel);
3112 packet_send();
3113 }
3114 }
3115
3116 /* -- X11 forwarding */
3117
3118 /*
3119 * Creates an internet domain socket for listening for X11 connections.
3120 * Returns 0 and a suitable display number for the DISPLAY variable
3121 * stored in display_numberp , or -1 if an error occurs.
3122 */
3123 int
3124 x11_create_display_inet(int x11_display_offset, int x11_use_localhost,
3125 int single_connection, u_int *display_numberp, int **chanids)
3126 {
3127 Channel *nc = NULL;
3128 int display_number, sock;
3129 u_short port;
3130 struct addrinfo hints, *ai, *aitop;
3131 char strport[NI_MAXSERV];
3132 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
3133
3134 if (chanids == NULL)
3135 return -1;
3136
3137 for (display_number = x11_display_offset;
3138 display_number < MAX_DISPLAYS;
3139 display_number++) {
3140 port = 6000 + display_number;
3141 memset(&hints, 0, sizeof(hints));
3142 hints.ai_family = IPv4or6;
3143 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE;
3144 hints.ai_socktype = SOCK_STREAM;
3145 snprintf(strport, sizeof strport, "%d", port);
3146 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
3147 error("getaddrinfo: %.100s", ssh_gai_strerror(gaierr));
3148 return -1;
3149 }
3150 for (ai = aitop; ai; ai = ai->ai_next) {
3151 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
3152 continue;
3153 sock = socket(ai->ai_family, ai->ai_socktype,
3154 ai->ai_protocol);
3155 if (sock < 0) {
3156 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
3157 error("socket: %.100s", strerror(errno));
3158 freeaddrinfo(aitop);
3159 return -1;
3160 } else {
3161 debug("x11_create_display_inet: Socket family %d not supported",
3162 ai->ai_family);
3163 continue;
3164 }
3165 }
3166 #ifdef IPV6_V6ONLY
3167 if (ai->ai_family == AF_INET6) {
3168 int on = 1;
3169 if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) < 0)
3170 error("setsockopt IPV6_V6ONLY: %.100s", strerror(errno));
3171 }
3172 #endif
3173 if (x11_use_localhost)
3174 channel_set_reuseaddr(sock);
3175 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
3176 debug2("bind port %d: %.100s", port, strerror(errno));
3177 close(sock);
3178
3179 for (n = 0; n < num_socks; n++) {
3180 close(socks[n]);
3181 }
3182 num_socks = 0;
3183 break;
3184 }
3185 socks[num_socks++] = sock;
3186 if (num_socks == NUM_SOCKS)
3187 break;
3188 }
3189 freeaddrinfo(aitop);
3190 if (num_socks > 0)
3191 break;
3192 }
3193 if (display_number >= MAX_DISPLAYS) {
3194 error("Failed to allocate internet-domain X11 display socket.");
3195 return -1;
3196 }
3197 /* Start listening for connections on the socket. */
3198 for (n = 0; n < num_socks; n++) {
3199 sock = socks[n];
3200 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
3201 error("listen: %.100s", strerror(errno));
3202 close(sock);
3203 return -1;
3204 }
3205 }
3206
3207 /* Allocate a channel for each socket. */
3208 *chanids = xcalloc(num_socks + 1, sizeof(**chanids));
3209 for (n = 0; n < num_socks; n++) {
3210 sock = socks[n];
3211 /* Is this really necassary? */
3212 if (hpn_disabled)
3213 nc = channel_new("x11 listener",
3214 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
3215 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
3216 0, "X11 inet listener", 1);
3217 else
3218 nc = channel_new("x11 listener",
3219 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
3220 hpn_buffer_size, CHAN_X11_PACKET_DEFAULT,
3221 0, "X11 inet listener", 1);
3222 nc->single_connection = single_connection;
3223 (*chanids)[n] = nc->self;
3224 }
3225 (*chanids)[n] = -1;
3226
3227 /* Return the display number for the DISPLAY environment variable. */
3228 *display_numberp = display_number;
3229 return (0);
3230 }
3231
3232 static int
3233 connect_local_xsocket_path(const char *pathname)
3234 {
3235 int sock;
3236 struct sockaddr_un addr;
3237
3238 sock = socket(AF_UNIX, SOCK_STREAM, 0);
3239 if (sock < 0)
3240 error("socket: %.100s", strerror(errno));
3241 memset(&addr, 0, sizeof(addr));
3242 addr.sun_family = AF_UNIX;
3243 strlcpy(addr.sun_path, pathname, sizeof addr.sun_path);
3244 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0)
3245 return sock;
3246 close(sock);
3247 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
3248 return -1;
3249 }
3250
3251 static int
3252 connect_local_xsocket(u_int dnr)
3253 {
3254 char buf[1024];
3255 snprintf(buf, sizeof buf, _PATH_UNIX_X, dnr);
3256 return connect_local_xsocket_path(buf);
3257 }
3258
3259 int
3260 x11_connect_display(void)
3261 {
3262 u_int display_number;
3263 const char *display;
3264 char buf[1024], *cp;
3265 struct addrinfo hints, *ai, *aitop;
3266 char strport[NI_MAXSERV];
3267 int gaierr, sock = 0;
3268
3269 /* Try to open a socket for the local X server. */
3270 display = getenv("DISPLAY");
3271 if (!display) {
3272 error("DISPLAY not set.");
3273 return -1;
3274 }
3275 /*
3276 * Now we decode the value of the DISPLAY variable and make a
3277 * connection to the real X server.
3278 */
3279
3280 /* Check if the display is from launchd. */
3281 #ifdef __APPLE__
3282 if (strncmp(display, "/tmp/launch", 11) == 0) {
3283 sock = connect_local_xsocket_path(display);
3284 if (sock < 0)
3285 return -1;
3286
3287 /* OK, we now have a connection to the display. */
3288 return sock;
3289 }
3290 #endif
3291 /*
3292 * Check if it is a unix domain socket. Unix domain displays are in
3293 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
3294 */
3295 if (strncmp(display, "unix:", 5) == 0 ||
3296 display[0] == ':') {
3297 /* Connect to the unix domain socket. */
3298 if (sscanf(strrchr(display, ':') + 1, "%u", &display_number) != 1) {
3299 error("Could not parse display number from DISPLAY: %.100s",
3300 display);
3301 return -1;
3302 }
3303 /* Create a socket. */
3304 sock = connect_local_xsocket(display_number);
3305 if (sock < 0)
3306 return -1;
3307
3308 /* OK, we now have a connection to the display. */
3309 return sock;
3310 }
3311 /*
3312 * Connect to an inet socket. The DISPLAY value is supposedly
3313 * hostname:d[.s], where hostname may also be numeric IP address.
3314 */
3315 strlcpy(buf, display, sizeof(buf));
3316 cp = strchr(buf, ':');
3317 if (!cp) {
3318 error("Could not find ':' in DISPLAY: %.100s", display);
3319 return -1;
3320 }
3321 *cp = 0;
3322 /* buf now contains the host name. But first we parse the display number. */
3323 if (sscanf(cp + 1, "%u", &display_number) != 1) {
3324 error("Could not parse display number from DISPLAY: %.100s",
3325 display);
3326 return -1;
3327 }
3328
3329 /* Look up the host address */
3330 memset(&hints, 0, sizeof(hints));
3331 hints.ai_family = IPv4or6;
3332 hints.ai_socktype = SOCK_STREAM;
3333 snprintf(strport, sizeof strport, "%u", 6000 + display_number);
3334 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
3335 error("%.100s: unknown host. (%s)", buf,
3336 ssh_gai_strerror(gaierr));
3337 return -1;
3338 }
3339 for (ai = aitop; ai; ai = ai->ai_next) {
3340 /* Create a socket. */
3341 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
3342 if (sock < 0) {
3343 debug2("socket: %.100s", strerror(errno));
3344 continue;
3345 }
3346 /* Connect it to the display. */
3347 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
3348 debug2("connect %.100s port %u: %.100s", buf,
3349 6000 + display_number, strerror(errno));
3350 close(sock);
3351 continue;
3352 }
3353 /* Success */
3354 break;
3355 }
3356 freeaddrinfo(aitop);
3357 if (!ai) {
3358 error("connect %.100s port %u: %.100s", buf, 6000 + display_number,
3359 strerror(errno));
3360 return -1;
3361 }
3362 set_nodelay(sock);
3363 return sock;
3364 }
3365
3366 /*
3367 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
3368 * the remote channel number. We should do whatever we want, and respond
3369 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
3370 */
3371
3372 /* ARGSUSED */
3373 void
3374 x11_input_open(int type, u_int32_t seq, void *ctxt)
3375 {
3376 Channel *c = NULL;
3377 int remote_id, sock = 0;
3378 char *remote_host;
3379
3380 debug("Received X11 open request.");
3381
3382 remote_id = packet_get_int();
3383
3384 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
3385 remote_host = packet_get_string(NULL);
3386 } else {
3387 remote_host = xstrdup("unknown (remote did not supply name)");
3388 }
3389 packet_check_eom();
3390
3391 /* Obtain a connection to the real X display. */
3392 sock = x11_connect_display();
3393 if (sock != -1) {
3394 /* Allocate a channel for this connection. */
3395 c = channel_new("connected x11 socket",
3396 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
3397 remote_host, 1);
3398 c->remote_id = remote_id;
3399 c->force_drain = 1;
3400 }
3401 xfree(remote_host);
3402 if (c == NULL) {
3403 /* Send refusal to the remote host. */
3404 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3405 packet_put_int(remote_id);
3406 } else {
3407 /* Send a confirmation to the remote host. */
3408 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
3409 packet_put_int(remote_id);
3410 packet_put_int(c->self);
3411 }
3412 packet_send();
3413 }
3414
3415 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
3416 /* ARGSUSED */
3417 void
3418 deny_input_open(int type, u_int32_t seq, void *ctxt)
3419 {
3420 int rchan = packet_get_int();
3421
3422 switch (type) {
3423 case SSH_SMSG_AGENT_OPEN:
3424 error("Warning: ssh server tried agent forwarding.");
3425 break;
3426 case SSH_SMSG_X11_OPEN:
3427 error("Warning: ssh server tried X11 forwarding.");
3428 break;
3429 default:
3430 error("deny_input_open: type %d", type);
3431 break;
3432 }
3433 error("Warning: this is probably a break-in attempt by a malicious server.");
3434 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3435 packet_put_int(rchan);
3436 packet_send();
3437 }
3438
3439 /*
3440 * Requests forwarding of X11 connections, generates fake authentication
3441 * data, and enables authentication spoofing.
3442 * This should be called in the client only.
3443 */
3444 void
3445 x11_request_forwarding_with_spoofing(int client_session_id, const char *disp,
3446 const char *proto, const char *data)
3447 {
3448 u_int data_len = (u_int) strlen(data) / 2;
3449 u_int i, value;
3450 char *new_data;
3451 int screen_number;
3452 const char *cp;
3453 u_int32_t rnd = 0;
3454
3455 if (x11_saved_display == NULL)
3456 x11_saved_display = xstrdup(disp);
3457 else if (strcmp(disp, x11_saved_display) != 0) {
3458 error("x11_request_forwarding_with_spoofing: different "
3459 "$DISPLAY already forwarded");
3460 return;
3461 }
3462
3463 cp = strchr(disp, ':');
3464 if (cp)
3465 cp = strchr(cp, '.');
3466 if (cp)
3467 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL);
3468 else
3469 screen_number = 0;
3470
3471 if (x11_saved_proto == NULL) {
3472 /* Save protocol name. */
3473 x11_saved_proto = xstrdup(proto);
3474 /*
3475 * Extract real authentication data and generate fake data
3476 * of the same length.
3477 */
3478 x11_saved_data = xmalloc(data_len);
3479 x11_fake_data = xmalloc(data_len);
3480 for (i = 0; i < data_len; i++) {
3481 if (sscanf(data + 2 * i, "%2x", &value) != 1)
3482 fatal("x11_request_forwarding: bad "
3483 "authentication data: %.100s", data);
3484 if (i % 4 == 0)
3485 rnd = arc4random();
3486 x11_saved_data[i] = value;
3487 x11_fake_data[i] = rnd & 0xff;
3488 rnd >>= 8;
3489 }
3490 x11_saved_data_len = data_len;
3491 x11_fake_data_len = data_len;
3492 }
3493
3494 /* Convert the fake data into hex. */
3495 new_data = tohex(x11_fake_data, data_len);
3496
3497 /* Send the request packet. */
3498 if (compat20) {
3499 channel_request_start(client_session_id, "x11-req", 0);
3500 packet_put_char(0); /* XXX bool single connection */
3501 } else {
3502 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
3503 }
3504 packet_put_cstring(proto);
3505 packet_put_cstring(new_data);
3506 packet_put_int(screen_number);
3507 packet_send();
3508 packet_write_wait();
3509 xfree(new_data);
3510 }
3511
3512
3513 /* -- agent forwarding */
3514
3515 /* Sends a message to the server to request authentication fd forwarding. */
3516
3517 void
3518 auth_request_forwarding(void)
3519 {
3520 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
3521 packet_send();
3522 packet_write_wait();
3523 }
DragonFly BSD