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- dtucker [auth-sia.c] Roll back the change for bug #1241 as it apparently
[openssh-git.git] / channels.c
blobefb04d65537dedf07d0b229f1e60a563be555f49
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 /* -- channel core */
173
174 Channel *
175 channel_by_id(int id)
176 {
177 Channel *c;
178
179 if (id < 0 || (u_int)id >= channels_alloc) {
180 logit("channel_by_id: %d: bad id", id);
181 return NULL;
182 }
183 c = channels[id];
184 if (c == NULL) {
185 logit("channel_by_id: %d: bad id: channel free", id);
186 return NULL;
187 }
188 return c;
189 }
190
191 /*
192 * Returns the channel if it is allowed to receive protocol messages.
193 * Private channels, like listening sockets, may not receive messages.
194 */
195 Channel *
196 channel_lookup(int id)
197 {
198 Channel *c;
199
200 if ((c = channel_by_id(id)) == NULL)
201 return (NULL);
202
203 switch (c->type) {
204 case SSH_CHANNEL_X11_OPEN:
205 case SSH_CHANNEL_LARVAL:
206 case SSH_CHANNEL_CONNECTING:
207 case SSH_CHANNEL_DYNAMIC:
208 case SSH_CHANNEL_OPENING:
209 case SSH_CHANNEL_OPEN:
210 case SSH_CHANNEL_INPUT_DRAINING:
211 case SSH_CHANNEL_OUTPUT_DRAINING:
212 return (c);
213 }
214 logit("Non-public channel %d, type %d.", id, c->type);
215 return (NULL);
216 }
217
218 /*
219 * Register filedescriptors for a channel, used when allocating a channel or
220 * when the channel consumer/producer is ready, e.g. shell exec'd
221 */
222 static void
223 channel_register_fds(Channel *c, int rfd, int wfd, int efd,
224 int extusage, int nonblock, int is_tty)
225 {
226 /* Update the maximum file descriptor value. */
227 channel_max_fd = MAX(channel_max_fd, rfd);
228 channel_max_fd = MAX(channel_max_fd, wfd);
229 channel_max_fd = MAX(channel_max_fd, efd);
230
231 /* XXX set close-on-exec -markus */
232
233 c->rfd = rfd;
234 c->wfd = wfd;
235 c->sock = (rfd == wfd) ? rfd : -1;
236 c->ctl_fd = -1; /* XXX: set elsewhere */
237 c->efd = efd;
238 c->extended_usage = extusage;
239
240 if ((c->isatty = is_tty) != 0)
241 debug2("channel %d: rfd %d isatty", c->self, c->rfd);
242 c->wfd_isatty = is_tty || isatty(c->wfd);
243
244 /* enable nonblocking mode */
245 if (nonblock) {
246 if (rfd != -1)
247 set_nonblock(rfd);
248 if (wfd != -1)
249 set_nonblock(wfd);
250 if (efd != -1)
251 set_nonblock(efd);
252 }
253 }
254
255 /*
256 * Allocate a new channel object and set its type and socket. This will cause
257 * remote_name to be freed.
258 */
259 Channel *
260 channel_new(char *ctype, int type, int rfd, int wfd, int efd,
261 u_int window, u_int maxpack, int extusage, char *remote_name, int nonblock)
262 {
263 int found;
264 u_int i;
265 Channel *c;
266
267 /* Do initial allocation if this is the first call. */
268 if (channels_alloc == 0) {
269 channels_alloc = 10;
270 channels = xcalloc(channels_alloc, sizeof(Channel *));
271 for (i = 0; i < channels_alloc; i++)
272 channels[i] = NULL;
273 }
274 /* Try to find a free slot where to put the new channel. */
275 for (found = -1, i = 0; i < channels_alloc; i++)
276 if (channels[i] == NULL) {
277 /* Found a free slot. */
278 found = (int)i;
279 break;
280 }
281 if (found < 0) {
282 /* There are no free slots. Take last+1 slot and expand the array. */
283 found = channels_alloc;
284 if (channels_alloc > 10000)
285 fatal("channel_new: internal error: channels_alloc %d "
286 "too big.", channels_alloc);
287 channels = xrealloc(channels, channels_alloc + 10,
288 sizeof(Channel *));
289 channels_alloc += 10;
290 debug2("channel: expanding %d", channels_alloc);
291 for (i = found; i < channels_alloc; i++)
292 channels[i] = NULL;
293 }
294 /* Initialize and return new channel. */
295 c = channels[found] = xcalloc(1, sizeof(Channel));
296 buffer_init(&c->input);
297 buffer_init(&c->output);
298 buffer_init(&c->extended);
299 c->path = NULL;
300 c->ostate = CHAN_OUTPUT_OPEN;
301 c->istate = CHAN_INPUT_OPEN;
302 c->flags = 0;
303 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock, 0);
304 c->self = found;
305 c->type = type;
306 c->ctype = ctype;
307 c->local_window = window;
308 c->local_window_max = window;
309 c->local_consumed = 0;
310 c->local_maxpacket = maxpack;
311 c->remote_id = -1;
312 c->remote_name = xstrdup(remote_name);
313 c->remote_window = 0;
314 c->remote_maxpacket = 0;
315 c->force_drain = 0;
316 c->single_connection = 0;
317 c->detach_user = NULL;
318 c->detach_close = 0;
319 c->open_confirm = NULL;
320 c->open_confirm_ctx = NULL;
321 c->input_filter = NULL;
322 c->output_filter = NULL;
323 c->filter_ctx = NULL;
324 c->filter_cleanup = NULL;
325 TAILQ_INIT(&c->status_confirms);
326 debug("channel %d: new [%s]", found, remote_name);
327 return c;
328 }
329
330 static int
331 channel_find_maxfd(void)
332 {
333 u_int i;
334 int max = 0;
335 Channel *c;
336
337 for (i = 0; i < channels_alloc; i++) {
338 c = channels[i];
339 if (c != NULL) {
340 max = MAX(max, c->rfd);
341 max = MAX(max, c->wfd);
342 max = MAX(max, c->efd);
343 }
344 }
345 return max;
346 }
347
348 int
349 channel_close_fd(int *fdp)
350 {
351 int ret = 0, fd = *fdp;
352
353 if (fd != -1) {
354 ret = close(fd);
355 *fdp = -1;
356 if (fd == channel_max_fd)
357 channel_max_fd = channel_find_maxfd();
358 }
359 return ret;
360 }
361
362 /* Close all channel fd/socket. */
363 static void
364 channel_close_fds(Channel *c)
365 {
366 debug3("channel %d: close_fds r %d w %d e %d c %d",
367 c->self, c->rfd, c->wfd, c->efd, c->ctl_fd);
368
369 channel_close_fd(&c->sock);
370 channel_close_fd(&c->ctl_fd);
371 channel_close_fd(&c->rfd);
372 channel_close_fd(&c->wfd);
373 channel_close_fd(&c->efd);
374 }
375
376 /* Free the channel and close its fd/socket. */
377 void
378 channel_free(Channel *c)
379 {
380 char *s;
381 u_int i, n;
382 struct channel_confirm *cc;
383
384 for (n = 0, i = 0; i < channels_alloc; i++)
385 if (channels[i])
386 n++;
387 debug("channel %d: free: %s, nchannels %u", c->self,
388 c->remote_name ? c->remote_name : "???", n);
389
390 s = channel_open_message();
391 debug3("channel %d: status: %s", c->self, s);
392 xfree(s);
393
394 if (c->sock != -1)
395 shutdown(c->sock, SHUT_RDWR);
396 if (c->ctl_fd != -1)
397 shutdown(c->ctl_fd, SHUT_RDWR);
398 channel_close_fds(c);
399 buffer_free(&c->input);
400 buffer_free(&c->output);
401 buffer_free(&c->extended);
402 if (c->remote_name) {
403 xfree(c->remote_name);
404 c->remote_name = NULL;
405 }
406 if (c->path) {
407 xfree(c->path);
408 c->path = NULL;
409 }
410 while ((cc = TAILQ_FIRST(&c->status_confirms)) != NULL) {
411 if (cc->abandon_cb != NULL)
412 cc->abandon_cb(c, cc->ctx);
413 TAILQ_REMOVE(&c->status_confirms, cc, entry);
414 bzero(cc, sizeof(*cc));
415 xfree(cc);
416 }
417 if (c->filter_cleanup != NULL && c->filter_ctx != NULL)
418 c->filter_cleanup(c->self, c->filter_ctx);
419 channels[c->self] = NULL;
420 xfree(c);
421 }
422
423 void
424 channel_free_all(void)
425 {
426 u_int i;
427
428 for (i = 0; i < channels_alloc; i++)
429 if (channels[i] != NULL)
430 channel_free(channels[i]);
431 }
432
433 /*
434 * Closes the sockets/fds of all channels. This is used to close extra file
435 * descriptors after a fork.
436 */
437 void
438 channel_close_all(void)
439 {
440 u_int i;
441
442 for (i = 0; i < channels_alloc; i++)
443 if (channels[i] != NULL)
444 channel_close_fds(channels[i]);
445 }
446
447 /*
448 * Stop listening to channels.
449 */
450 void
451 channel_stop_listening(void)
452 {
453 u_int i;
454 Channel *c;
455
456 for (i = 0; i < channels_alloc; i++) {
457 c = channels[i];
458 if (c != NULL) {
459 switch (c->type) {
460 case SSH_CHANNEL_AUTH_SOCKET:
461 case SSH_CHANNEL_PORT_LISTENER:
462 case SSH_CHANNEL_RPORT_LISTENER:
463 case SSH_CHANNEL_X11_LISTENER:
464 channel_close_fd(&c->sock);
465 channel_free(c);
466 break;
467 }
468 }
469 }
470 }
471
472 /*
473 * Returns true if no channel has too much buffered data, and false if one or
474 * more channel is overfull.
475 */
476 int
477 channel_not_very_much_buffered_data(void)
478 {
479 u_int i;
480 Channel *c;
481
482 for (i = 0; i < channels_alloc; i++) {
483 c = channels[i];
484 if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
485 #if 0
486 if (!compat20 &&
487 buffer_len(&c->input) > packet_get_maxsize()) {
488 debug2("channel %d: big input buffer %d",
489 c->self, buffer_len(&c->input));
490 return 0;
491 }
492 #endif
493 if (buffer_len(&c->output) > packet_get_maxsize()) {
494 debug2("channel %d: big output buffer %u > %u",
495 c->self, buffer_len(&c->output),
496 packet_get_maxsize());
497 return 0;
498 }
499 }
500 }
501 return 1;
502 }
503
504 /* Returns true if any channel is still open. */
505 int
506 channel_still_open(void)
507 {
508 u_int i;
509 Channel *c;
510
511 for (i = 0; i < channels_alloc; i++) {
512 c = channels[i];
513 if (c == NULL)
514 continue;
515 switch (c->type) {
516 case SSH_CHANNEL_X11_LISTENER:
517 case SSH_CHANNEL_PORT_LISTENER:
518 case SSH_CHANNEL_RPORT_LISTENER:
519 case SSH_CHANNEL_CLOSED:
520 case SSH_CHANNEL_AUTH_SOCKET:
521 case SSH_CHANNEL_DYNAMIC:
522 case SSH_CHANNEL_CONNECTING:
523 case SSH_CHANNEL_ZOMBIE:
524 continue;
525 case SSH_CHANNEL_LARVAL:
526 if (!compat20)
527 fatal("cannot happen: SSH_CHANNEL_LARVAL");
528 continue;
529 case SSH_CHANNEL_OPENING:
530 case SSH_CHANNEL_OPEN:
531 case SSH_CHANNEL_X11_OPEN:
532 return 1;
533 case SSH_CHANNEL_INPUT_DRAINING:
534 case SSH_CHANNEL_OUTPUT_DRAINING:
535 if (!compat13)
536 fatal("cannot happen: OUT_DRAIN");
537 return 1;
538 default:
539 fatal("channel_still_open: bad channel type %d", c->type);
540 /* NOTREACHED */
541 }
542 }
543 return 0;
544 }
545
546 /* Returns the id of an open channel suitable for keepaliving */
547 int
548 channel_find_open(void)
549 {
550 u_int i;
551 Channel *c;
552
553 for (i = 0; i < channels_alloc; i++) {
554 c = channels[i];
555 if (c == NULL || c->remote_id < 0)
556 continue;
557 switch (c->type) {
558 case SSH_CHANNEL_CLOSED:
559 case SSH_CHANNEL_DYNAMIC:
560 case SSH_CHANNEL_X11_LISTENER:
561 case SSH_CHANNEL_PORT_LISTENER:
562 case SSH_CHANNEL_RPORT_LISTENER:
563 case SSH_CHANNEL_OPENING:
564 case SSH_CHANNEL_CONNECTING:
565 case SSH_CHANNEL_ZOMBIE:
566 continue;
567 case SSH_CHANNEL_LARVAL:
568 case SSH_CHANNEL_AUTH_SOCKET:
569 case SSH_CHANNEL_OPEN:
570 case SSH_CHANNEL_X11_OPEN:
571 return i;
572 case SSH_CHANNEL_INPUT_DRAINING:
573 case SSH_CHANNEL_OUTPUT_DRAINING:
574 if (!compat13)
575 fatal("cannot happen: OUT_DRAIN");
576 return i;
577 default:
578 fatal("channel_find_open: bad channel type %d", c->type);
579 /* NOTREACHED */
580 }
581 }
582 return -1;
583 }
584
585
586 /*
587 * Returns a message describing the currently open forwarded connections,
588 * suitable for sending to the client. The message contains crlf pairs for
589 * newlines.
590 */
591 char *
592 channel_open_message(void)
593 {
594 Buffer buffer;
595 Channel *c;
596 char buf[1024], *cp;
597 u_int i;
598
599 buffer_init(&buffer);
600 snprintf(buf, sizeof buf, "The following connections are open:\r\n");
601 buffer_append(&buffer, buf, strlen(buf));
602 for (i = 0; i < channels_alloc; i++) {
603 c = channels[i];
604 if (c == NULL)
605 continue;
606 switch (c->type) {
607 case SSH_CHANNEL_X11_LISTENER:
608 case SSH_CHANNEL_PORT_LISTENER:
609 case SSH_CHANNEL_RPORT_LISTENER:
610 case SSH_CHANNEL_CLOSED:
611 case SSH_CHANNEL_AUTH_SOCKET:
612 case SSH_CHANNEL_ZOMBIE:
613 continue;
614 case SSH_CHANNEL_LARVAL:
615 case SSH_CHANNEL_OPENING:
616 case SSH_CHANNEL_CONNECTING:
617 case SSH_CHANNEL_DYNAMIC:
618 case SSH_CHANNEL_OPEN:
619 case SSH_CHANNEL_X11_OPEN:
620 case SSH_CHANNEL_INPUT_DRAINING:
621 case SSH_CHANNEL_OUTPUT_DRAINING:
622 snprintf(buf, sizeof buf,
623 " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d cfd %d)\r\n",
624 c->self, c->remote_name,
625 c->type, c->remote_id,
626 c->istate, buffer_len(&c->input),
627 c->ostate, buffer_len(&c->output),
628 c->rfd, c->wfd, c->ctl_fd);
629 buffer_append(&buffer, buf, strlen(buf));
630 continue;
631 default:
632 fatal("channel_open_message: bad channel type %d", c->type);
633 /* NOTREACHED */
634 }
635 }
636 buffer_append(&buffer, "\0", 1);
637 cp = xstrdup(buffer_ptr(&buffer));
638 buffer_free(&buffer);
639 return cp;
640 }
641
642 void
643 channel_send_open(int id)
644 {
645 Channel *c = channel_lookup(id);
646
647 if (c == NULL) {
648 logit("channel_send_open: %d: bad id", id);
649 return;
650 }
651 debug2("channel %d: send open", id);
652 packet_start(SSH2_MSG_CHANNEL_OPEN);
653 packet_put_cstring(c->ctype);
654 packet_put_int(c->self);
655 packet_put_int(c->local_window);
656 packet_put_int(c->local_maxpacket);
657 packet_send();
658 }
659
660 void
661 channel_request_start(int id, char *service, int wantconfirm)
662 {
663 Channel *c = channel_lookup(id);
664
665 if (c == NULL) {
666 logit("channel_request_start: %d: unknown channel id", id);
667 return;
668 }
669 debug2("channel %d: request %s confirm %d", id, service, wantconfirm);
670 packet_start(SSH2_MSG_CHANNEL_REQUEST);
671 packet_put_int(c->remote_id);
672 packet_put_cstring(service);
673 packet_put_char(wantconfirm);
674 }
675
676 void
677 channel_register_status_confirm(int id, channel_confirm_cb *cb,
678 channel_confirm_abandon_cb *abandon_cb, void *ctx)
679 {
680 struct channel_confirm *cc;
681 Channel *c;
682
683 if ((c = channel_lookup(id)) == NULL)
684 fatal("channel_register_expect: %d: bad id", id);
685
686 cc = xmalloc(sizeof(*cc));
687 cc->cb = cb;
688 cc->abandon_cb = abandon_cb;
689 cc->ctx = ctx;
690 TAILQ_INSERT_TAIL(&c->status_confirms, cc, entry);
691 }
692
693 void
694 channel_register_open_confirm(int id, channel_callback_fn *fn, void *ctx)
695 {
696 Channel *c = channel_lookup(id);
697
698 if (c == NULL) {
699 logit("channel_register_open_confirm: %d: bad id", id);
700 return;
701 }
702 c->open_confirm = fn;
703 c->open_confirm_ctx = ctx;
704 }
705
706 void
707 channel_register_cleanup(int id, channel_callback_fn *fn, int do_close)
708 {
709 Channel *c = channel_by_id(id);
710
711 if (c == NULL) {
712 logit("channel_register_cleanup: %d: bad id", id);
713 return;
714 }
715 c->detach_user = fn;
716 c->detach_close = do_close;
717 }
718
719 void
720 channel_cancel_cleanup(int id)
721 {
722 Channel *c = channel_by_id(id);
723
724 if (c == NULL) {
725 logit("channel_cancel_cleanup: %d: bad id", id);
726 return;
727 }
728 c->detach_user = NULL;
729 c->detach_close = 0;
730 }
731
732 void
733 channel_register_filter(int id, channel_infilter_fn *ifn,
734 channel_outfilter_fn *ofn, channel_filter_cleanup_fn *cfn, void *ctx)
735 {
736 Channel *c = channel_lookup(id);
737
738 if (c == NULL) {
739 logit("channel_register_filter: %d: bad id", id);
740 return;
741 }
742 c->input_filter = ifn;
743 c->output_filter = ofn;
744 c->filter_ctx = ctx;
745 c->filter_cleanup = cfn;
746 }
747
748 void
749 channel_set_fds(int id, int rfd, int wfd, int efd,
750 int extusage, int nonblock, int is_tty, u_int window_max)
751 {
752 Channel *c = channel_lookup(id);
753
754 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
755 fatal("channel_activate for non-larval channel %d.", id);
756 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock, is_tty);
757 c->type = SSH_CHANNEL_OPEN;
758 c->local_window = c->local_window_max = window_max;
759 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
760 packet_put_int(c->remote_id);
761 packet_put_int(c->local_window);
762 packet_send();
763 }
764
765 /*
766 * 'channel_pre*' are called just before select() to add any bits relevant to
767 * channels in the select bitmasks.
768 */
769 /*
770 * 'channel_post*': perform any appropriate operations for channels which
771 * have events pending.
772 */
773 typedef void chan_fn(Channel *c, fd_set *readset, fd_set *writeset);
774 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
775 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
776
777 /* ARGSUSED */
778 static void
779 channel_pre_listener(Channel *c, fd_set *readset, fd_set *writeset)
780 {
781 FD_SET(c->sock, readset);
782 }
783
784 /* ARGSUSED */
785 static void
786 channel_pre_connecting(Channel *c, fd_set *readset, fd_set *writeset)
787 {
788 debug3("channel %d: waiting for connection", c->self);
789 FD_SET(c->sock, writeset);
790 }
791
792 static void
793 channel_pre_open_13(Channel *c, fd_set *readset, fd_set *writeset)
794 {
795 if (buffer_len(&c->input) < packet_get_maxsize())
796 FD_SET(c->sock, readset);
797 if (buffer_len(&c->output) > 0)
798 FD_SET(c->sock, writeset);
799 }
800
801 static void
802 channel_pre_open(Channel *c, fd_set *readset, fd_set *writeset)
803 {
804 u_int limit = compat20 ? c->remote_window : packet_get_maxsize();
805
806 if (c->istate == CHAN_INPUT_OPEN &&
807 limit > 0 &&
808 buffer_len(&c->input) < limit &&
809 buffer_check_alloc(&c->input, CHAN_RBUF))
810 FD_SET(c->rfd, readset);
811 if (c->ostate == CHAN_OUTPUT_OPEN ||
812 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
813 if (buffer_len(&c->output) > 0) {
814 FD_SET(c->wfd, writeset);
815 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
816 if (CHANNEL_EFD_OUTPUT_ACTIVE(c))
817 debug2("channel %d: obuf_empty delayed efd %d/(%d)",
818 c->self, c->efd, buffer_len(&c->extended));
819 else
820 chan_obuf_empty(c);
821 }
822 }
823 /** XXX check close conditions, too */
824 if (compat20 && c->efd != -1 &&
825 !(c->istate == CHAN_INPUT_CLOSED && c->ostate == CHAN_OUTPUT_CLOSED)) {
826 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
827 buffer_len(&c->extended) > 0)
828 FD_SET(c->efd, writeset);
829 else if (!(c->flags & CHAN_EOF_SENT) &&
830 c->extended_usage == CHAN_EXTENDED_READ &&
831 buffer_len(&c->extended) < c->remote_window)
832 FD_SET(c->efd, readset);
833 }
834 /* XXX: What about efd? races? */
835 if (compat20 && c->ctl_fd != -1 &&
836 c->istate == CHAN_INPUT_OPEN && c->ostate == CHAN_OUTPUT_OPEN)
837 FD_SET(c->ctl_fd, readset);
838 }
839
840 /* ARGSUSED */
841 static void
842 channel_pre_input_draining(Channel *c, fd_set *readset, fd_set *writeset)
843 {
844 if (buffer_len(&c->input) == 0) {
845 packet_start(SSH_MSG_CHANNEL_CLOSE);
846 packet_put_int(c->remote_id);
847 packet_send();
848 c->type = SSH_CHANNEL_CLOSED;
849 debug2("channel %d: closing after input drain.", c->self);
850 }
851 }
852
853 /* ARGSUSED */
854 static void
855 channel_pre_output_draining(Channel *c, fd_set *readset, fd_set *writeset)
856 {
857 if (buffer_len(&c->output) == 0)
858 chan_mark_dead(c);
859 else
860 FD_SET(c->sock, writeset);
861 }
862
863 /*
864 * This is a special state for X11 authentication spoofing. An opened X11
865 * connection (when authentication spoofing is being done) remains in this
866 * state until the first packet has been completely read. The authentication
867 * data in that packet is then substituted by the real data if it matches the
868 * fake data, and the channel is put into normal mode.
869 * XXX All this happens at the client side.
870 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
871 */
872 static int
873 x11_open_helper(Buffer *b)
874 {
875 u_char *ucp;
876 u_int proto_len, data_len;
877
878 /* Check if the fixed size part of the packet is in buffer. */
879 if (buffer_len(b) < 12)
880 return 0;
881
882 /* Parse the lengths of variable-length fields. */
883 ucp = buffer_ptr(b);
884 if (ucp[0] == 0x42) { /* Byte order MSB first. */
885 proto_len = 256 * ucp[6] + ucp[7];
886 data_len = 256 * ucp[8] + ucp[9];
887 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
888 proto_len = ucp[6] + 256 * ucp[7];
889 data_len = ucp[8] + 256 * ucp[9];
890 } else {
891 debug2("Initial X11 packet contains bad byte order byte: 0x%x",
892 ucp[0]);
893 return -1;
894 }
895
896 /* Check if the whole packet is in buffer. */
897 if (buffer_len(b) <
898 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
899 return 0;
900
901 /* Check if authentication protocol matches. */
902 if (proto_len != strlen(x11_saved_proto) ||
903 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
904 debug2("X11 connection uses different authentication protocol.");
905 return -1;
906 }
907 /* Check if authentication data matches our fake data. */
908 if (data_len != x11_fake_data_len ||
909 memcmp(ucp + 12 + ((proto_len + 3) & ~3),
910 x11_fake_data, x11_fake_data_len) != 0) {
911 debug2("X11 auth data does not match fake data.");
912 return -1;
913 }
914 /* Check fake data length */
915 if (x11_fake_data_len != x11_saved_data_len) {
916 error("X11 fake_data_len %d != saved_data_len %d",
917 x11_fake_data_len, x11_saved_data_len);
918 return -1;
919 }
920 /*
921 * Received authentication protocol and data match
922 * our fake data. Substitute the fake data with real
923 * data.
924 */
925 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
926 x11_saved_data, x11_saved_data_len);
927 return 1;
928 }
929
930 static void
931 channel_pre_x11_open_13(Channel *c, fd_set *readset, fd_set *writeset)
932 {
933 int ret = x11_open_helper(&c->output);
934
935 if (ret == 1) {
936 /* Start normal processing for the channel. */
937 c->type = SSH_CHANNEL_OPEN;
938 channel_pre_open_13(c, readset, writeset);
939 } else if (ret == -1) {
940 /*
941 * We have received an X11 connection that has bad
942 * authentication information.
943 */
944 logit("X11 connection rejected because of wrong authentication.");
945 buffer_clear(&c->input);
946 buffer_clear(&c->output);
947 channel_close_fd(&c->sock);
948 c->sock = -1;
949 c->type = SSH_CHANNEL_CLOSED;
950 packet_start(SSH_MSG_CHANNEL_CLOSE);
951 packet_put_int(c->remote_id);
952 packet_send();
953 }
954 }
955
956 static void
957 channel_pre_x11_open(Channel *c, fd_set *readset, fd_set *writeset)
958 {
959 int ret = x11_open_helper(&c->output);
960
961 /* c->force_drain = 1; */
962
963 if (ret == 1) {
964 c->type = SSH_CHANNEL_OPEN;
965 channel_pre_open(c, readset, writeset);
966 } else if (ret == -1) {
967 logit("X11 connection rejected because of wrong authentication.");
968 debug2("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
969 chan_read_failed(c);
970 buffer_clear(&c->input);
971 chan_ibuf_empty(c);
972 buffer_clear(&c->output);
973 /* for proto v1, the peer will send an IEOF */
974 if (compat20)
975 chan_write_failed(c);
976 else
977 c->type = SSH_CHANNEL_OPEN;
978 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
979 }
980 }
981
982 /* try to decode a socks4 header */
983 /* ARGSUSED */
984 static int
985 channel_decode_socks4(Channel *c, fd_set *readset, fd_set *writeset)
986 {
987 char *p, *host;
988 u_int len, have, i, found, need;
989 char username[256];
990 struct {
991 u_int8_t version;
992 u_int8_t command;
993 u_int16_t dest_port;
994 struct in_addr dest_addr;
995 } s4_req, s4_rsp;
996
997 debug2("channel %d: decode socks4", c->self);
998
999 have = buffer_len(&c->input);
1000 len = sizeof(s4_req);
1001 if (have < len)
1002 return 0;
1003 p = buffer_ptr(&c->input);
1004
1005 need = 1;
1006 /* SOCKS4A uses an invalid IP address 0.0.0.x */
1007 if (p[4] == 0 && p[5] == 0 && p[6] == 0 && p[7] != 0) {
1008 debug2("channel %d: socks4a request", c->self);
1009 /* ... and needs an extra string (the hostname) */
1010 need = 2;
1011 }
1012 /* Check for terminating NUL on the string(s) */
1013 for (found = 0, i = len; i < have; i++) {
1014 if (p[i] == '\0') {
1015 found++;
1016 if (found == need)
1017 break;
1018 }
1019 if (i > 1024) {
1020 /* the peer is probably sending garbage */
1021 debug("channel %d: decode socks4: too long",
1022 c->self);
1023 return -1;
1024 }
1025 }
1026 if (found < need)
1027 return 0;
1028 buffer_get(&c->input, (char *)&s4_req.version, 1);
1029 buffer_get(&c->input, (char *)&s4_req.command, 1);
1030 buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
1031 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
1032 have = buffer_len(&c->input);
1033 p = buffer_ptr(&c->input);
1034 len = strlen(p);
1035 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
1036 len++; /* trailing '\0' */
1037 if (len > have)
1038 fatal("channel %d: decode socks4: len %d > have %d",
1039 c->self, len, have);
1040 strlcpy(username, p, sizeof(username));
1041 buffer_consume(&c->input, len);
1042
1043 if (c->path != NULL) {
1044 xfree(c->path);
1045 c->path = NULL;
1046 }
1047 if (need == 1) { /* SOCKS4: one string */
1048 host = inet_ntoa(s4_req.dest_addr);
1049 c->path = xstrdup(host);
1050 } else { /* SOCKS4A: two strings */
1051 have = buffer_len(&c->input);
1052 p = buffer_ptr(&c->input);
1053 len = strlen(p);
1054 debug2("channel %d: decode socks4a: host %s/%d",
1055 c->self, p, len);
1056 len++; /* trailing '\0' */
1057 if (len > have)
1058 fatal("channel %d: decode socks4a: len %d > have %d",
1059 c->self, len, have);
1060 if (len > NI_MAXHOST) {
1061 error("channel %d: hostname \"%.100s\" too long",
1062 c->self, p);
1063 return -1;
1064 }
1065 c->path = xstrdup(p);
1066 buffer_consume(&c->input, len);
1067 }
1068 c->host_port = ntohs(s4_req.dest_port);
1069
1070 debug2("channel %d: dynamic request: socks4 host %s port %u command %u",
1071 c->self, c->path, c->host_port, s4_req.command);
1072
1073 if (s4_req.command != 1) {
1074 debug("channel %d: cannot handle: %s cn %d",
1075 c->self, need == 1 ? "SOCKS4" : "SOCKS4A", s4_req.command);
1076 return -1;
1077 }
1078 s4_rsp.version = 0; /* vn: 0 for reply */
1079 s4_rsp.command = 90; /* cd: req granted */
1080 s4_rsp.dest_port = 0; /* ignored */
1081 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
1082 buffer_append(&c->output, &s4_rsp, sizeof(s4_rsp));
1083 return 1;
1084 }
1085
1086 /* try to decode a socks5 header */
1087 #define SSH_SOCKS5_AUTHDONE 0x1000
1088 #define SSH_SOCKS5_NOAUTH 0x00
1089 #define SSH_SOCKS5_IPV4 0x01
1090 #define SSH_SOCKS5_DOMAIN 0x03
1091 #define SSH_SOCKS5_IPV6 0x04
1092 #define SSH_SOCKS5_CONNECT 0x01
1093 #define SSH_SOCKS5_SUCCESS 0x00
1094
1095 /* ARGSUSED */
1096 static int
1097 channel_decode_socks5(Channel *c, fd_set *readset, fd_set *writeset)
1098 {
1099 struct {
1100 u_int8_t version;
1101 u_int8_t command;
1102 u_int8_t reserved;
1103 u_int8_t atyp;
1104 } s5_req, s5_rsp;
1105 u_int16_t dest_port;
1106 u_char *p, dest_addr[255+1], ntop[INET6_ADDRSTRLEN];
1107 u_int have, need, i, found, nmethods, addrlen, af;
1108
1109 debug2("channel %d: decode socks5", c->self);
1110 p = buffer_ptr(&c->input);
1111 if (p[0] != 0x05)
1112 return -1;
1113 have = buffer_len(&c->input);
1114 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) {
1115 /* format: ver | nmethods | methods */
1116 if (have < 2)
1117 return 0;
1118 nmethods = p[1];
1119 if (have < nmethods + 2)
1120 return 0;
1121 /* look for method: "NO AUTHENTICATION REQUIRED" */
1122 for (found = 0, i = 2; i < nmethods + 2; i++) {
1123 if (p[i] == SSH_SOCKS5_NOAUTH) {
1124 found = 1;
1125 break;
1126 }
1127 }
1128 if (!found) {
1129 debug("channel %d: method SSH_SOCKS5_NOAUTH not found",
1130 c->self);
1131 return -1;
1132 }
1133 buffer_consume(&c->input, nmethods + 2);
1134 buffer_put_char(&c->output, 0x05); /* version */
1135 buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH); /* method */
1136 FD_SET(c->sock, writeset);
1137 c->flags |= SSH_SOCKS5_AUTHDONE;
1138 debug2("channel %d: socks5 auth done", c->self);
1139 return 0; /* need more */
1140 }
1141 debug2("channel %d: socks5 post auth", c->self);
1142 if (have < sizeof(s5_req)+1)
1143 return 0; /* need more */
1144 memcpy(&s5_req, p, sizeof(s5_req));
1145 if (s5_req.version != 0x05 ||
1146 s5_req.command != SSH_SOCKS5_CONNECT ||
1147 s5_req.reserved != 0x00) {
1148 debug2("channel %d: only socks5 connect supported", c->self);
1149 return -1;
1150 }
1151 switch (s5_req.atyp){
1152 case SSH_SOCKS5_IPV4:
1153 addrlen = 4;
1154 af = AF_INET;
1155 break;
1156 case SSH_SOCKS5_DOMAIN:
1157 addrlen = p[sizeof(s5_req)];
1158 af = -1;
1159 break;
1160 case SSH_SOCKS5_IPV6:
1161 addrlen = 16;
1162 af = AF_INET6;
1163 break;
1164 default:
1165 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp);
1166 return -1;
1167 }
1168 need = sizeof(s5_req) + addrlen + 2;
1169 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1170 need++;
1171 if (have < need)
1172 return 0;
1173 buffer_consume(&c->input, sizeof(s5_req));
1174 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1175 buffer_consume(&c->input, 1); /* host string length */
1176 buffer_get(&c->input, (char *)&dest_addr, addrlen);
1177 buffer_get(&c->input, (char *)&dest_port, 2);
1178 dest_addr[addrlen] = '\0';
1179 if (c->path != NULL) {
1180 xfree(c->path);
1181 c->path = NULL;
1182 }
1183 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) {
1184 if (addrlen >= NI_MAXHOST) {
1185 error("channel %d: dynamic request: socks5 hostname "
1186 "\"%.100s\" too long", c->self, dest_addr);
1187 return -1;
1188 }
1189 c->path = xstrdup(dest_addr);
1190 } else {
1191 if (inet_ntop(af, dest_addr, ntop, sizeof(ntop)) == NULL)
1192 return -1;
1193 c->path = xstrdup(ntop);
1194 }
1195 c->host_port = ntohs(dest_port);
1196
1197 debug2("channel %d: dynamic request: socks5 host %s port %u command %u",
1198 c->self, c->path, c->host_port, s5_req.command);
1199
1200 s5_rsp.version = 0x05;
1201 s5_rsp.command = SSH_SOCKS5_SUCCESS;
1202 s5_rsp.reserved = 0; /* ignored */
1203 s5_rsp.atyp = SSH_SOCKS5_IPV4;
1204 ((struct in_addr *)&dest_addr)->s_addr = INADDR_ANY;
1205 dest_port = 0; /* ignored */
1206
1207 buffer_append(&c->output, &s5_rsp, sizeof(s5_rsp));
1208 buffer_append(&c->output, &dest_addr, sizeof(struct in_addr));
1209 buffer_append(&c->output, &dest_port, sizeof(dest_port));
1210 return 1;
1211 }
1212
1213 /* dynamic port forwarding */
1214 static void
1215 channel_pre_dynamic(Channel *c, fd_set *readset, fd_set *writeset)
1216 {
1217 u_char *p;
1218 u_int have;
1219 int ret;
1220
1221 have = buffer_len(&c->input);
1222 c->delayed = 0;
1223 debug2("channel %d: pre_dynamic: have %d", c->self, have);
1224 /* buffer_dump(&c->input); */
1225 /* check if the fixed size part of the packet is in buffer. */
1226 if (have < 3) {
1227 /* need more */
1228 FD_SET(c->sock, readset);
1229 return;
1230 }
1231 /* try to guess the protocol */
1232 p = buffer_ptr(&c->input);
1233 switch (p[0]) {
1234 case 0x04:
1235 ret = channel_decode_socks4(c, readset, writeset);
1236 break;
1237 case 0x05:
1238 ret = channel_decode_socks5(c, readset, writeset);
1239 break;
1240 default:
1241 ret = -1;
1242 break;
1243 }
1244 if (ret < 0) {
1245 chan_mark_dead(c);
1246 } else if (ret == 0) {
1247 debug2("channel %d: pre_dynamic: need more", c->self);
1248 /* need more */
1249 FD_SET(c->sock, readset);
1250 } else {
1251 /* switch to the next state */
1252 c->type = SSH_CHANNEL_OPENING;
1253 port_open_helper(c, "direct-tcpip");
1254 }
1255 }
1256
1257 /* This is our fake X11 server socket. */
1258 /* ARGSUSED */
1259 static void
1260 channel_post_x11_listener(Channel *c, fd_set *readset, fd_set *writeset)
1261 {
1262 Channel *nc;
1263 struct sockaddr_storage addr;
1264 int newsock;
1265 socklen_t addrlen;
1266 char buf[16384], *remote_ipaddr;
1267 int remote_port;
1268
1269 if (FD_ISSET(c->sock, readset)) {
1270 debug("X11 connection requested.");
1271 addrlen = sizeof(addr);
1272 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1273 if (c->single_connection) {
1274 debug2("single_connection: closing X11 listener.");
1275 channel_close_fd(&c->sock);
1276 chan_mark_dead(c);
1277 }
1278 if (newsock < 0) {
1279 error("accept: %.100s", strerror(errno));
1280 return;
1281 }
1282 set_nodelay(newsock);
1283 remote_ipaddr = get_peer_ipaddr(newsock);
1284 remote_port = get_peer_port(newsock);
1285 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1286 remote_ipaddr, remote_port);
1287
1288 nc = channel_new("accepted x11 socket",
1289 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1290 c->local_window_max, c->local_maxpacket, 0, buf, 1);
1291 if (compat20) {
1292 packet_start(SSH2_MSG_CHANNEL_OPEN);
1293 packet_put_cstring("x11");
1294 packet_put_int(nc->self);
1295 packet_put_int(nc->local_window_max);
1296 packet_put_int(nc->local_maxpacket);
1297 /* originator ipaddr and port */
1298 packet_put_cstring(remote_ipaddr);
1299 if (datafellows & SSH_BUG_X11FWD) {
1300 debug2("ssh2 x11 bug compat mode");
1301 } else {
1302 packet_put_int(remote_port);
1303 }
1304 packet_send();
1305 } else {
1306 packet_start(SSH_SMSG_X11_OPEN);
1307 packet_put_int(nc->self);
1308 if (packet_get_protocol_flags() &
1309 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1310 packet_put_cstring(buf);
1311 packet_send();
1312 }
1313 xfree(remote_ipaddr);
1314 }
1315 }
1316
1317 static void
1318 port_open_helper(Channel *c, char *rtype)
1319 {
1320 int direct;
1321 char buf[1024];
1322 char *remote_ipaddr = get_peer_ipaddr(c->sock);
1323 int remote_port = get_peer_port(c->sock);
1324
1325 direct = (strcmp(rtype, "direct-tcpip") == 0);
1326
1327 snprintf(buf, sizeof buf,
1328 "%s: listening port %d for %.100s port %d, "
1329 "connect from %.200s port %d",
1330 rtype, c->listening_port, c->path, c->host_port,
1331 remote_ipaddr, remote_port);
1332
1333 xfree(c->remote_name);
1334 c->remote_name = xstrdup(buf);
1335
1336 if (compat20) {
1337 packet_start(SSH2_MSG_CHANNEL_OPEN);
1338 packet_put_cstring(rtype);
1339 packet_put_int(c->self);
1340 packet_put_int(c->local_window_max);
1341 packet_put_int(c->local_maxpacket);
1342 if (direct) {
1343 /* target host, port */
1344 packet_put_cstring(c->path);
1345 packet_put_int(c->host_port);
1346 } else {
1347 /* listen address, port */
1348 packet_put_cstring(c->path);
1349 packet_put_int(c->listening_port);
1350 }
1351 /* originator host and port */
1352 packet_put_cstring(remote_ipaddr);
1353 packet_put_int((u_int)remote_port);
1354 packet_send();
1355 } else {
1356 packet_start(SSH_MSG_PORT_OPEN);
1357 packet_put_int(c->self);
1358 packet_put_cstring(c->path);
1359 packet_put_int(c->host_port);
1360 if (packet_get_protocol_flags() &
1361 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1362 packet_put_cstring(c->remote_name);
1363 packet_send();
1364 }
1365 xfree(remote_ipaddr);
1366 }
1367
1368 static void
1369 channel_set_reuseaddr(int fd)
1370 {
1371 int on = 1;
1372
1373 /*
1374 * Set socket options.
1375 * Allow local port reuse in TIME_WAIT.
1376 */
1377 if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1)
1378 error("setsockopt SO_REUSEADDR fd %d: %s", fd, strerror(errno));
1379 }
1380
1381 /*
1382 * This socket is listening for connections to a forwarded TCP/IP port.
1383 */
1384 /* ARGSUSED */
1385 static void
1386 channel_post_port_listener(Channel *c, fd_set *readset, fd_set *writeset)
1387 {
1388 Channel *nc;
1389 struct sockaddr_storage addr;
1390 int newsock, nextstate;
1391 socklen_t addrlen;
1392 char *rtype;
1393
1394 if (FD_ISSET(c->sock, readset)) {
1395 debug("Connection to port %d forwarding "
1396 "to %.100s port %d requested.",
1397 c->listening_port, c->path, c->host_port);
1398
1399 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1400 nextstate = SSH_CHANNEL_OPENING;
1401 rtype = "forwarded-tcpip";
1402 } else {
1403 if (c->host_port == 0) {
1404 nextstate = SSH_CHANNEL_DYNAMIC;
1405 rtype = "dynamic-tcpip";
1406 } else {
1407 nextstate = SSH_CHANNEL_OPENING;
1408 rtype = "direct-tcpip";
1409 }
1410 }
1411
1412 addrlen = sizeof(addr);
1413 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1414 if (newsock < 0) {
1415 error("accept: %.100s", strerror(errno));
1416 return;
1417 }
1418 set_nodelay(newsock);
1419 nc = channel_new(rtype, nextstate, newsock, newsock, -1,
1420 c->local_window_max, c->local_maxpacket, 0, rtype, 1);
1421 nc->listening_port = c->listening_port;
1422 nc->host_port = c->host_port;
1423 if (c->path != NULL)
1424 nc->path = xstrdup(c->path);
1425
1426 if (nextstate == SSH_CHANNEL_DYNAMIC) {
1427 /*
1428 * do not call the channel_post handler until
1429 * this flag has been reset by a pre-handler.
1430 * otherwise the FD_ISSET calls might overflow
1431 */
1432 nc->delayed = 1;
1433 } else {
1434 port_open_helper(nc, rtype);
1435 }
1436 }
1437 }
1438
1439 /*
1440 * This is the authentication agent socket listening for connections from
1441 * clients.
1442 */
1443 /* ARGSUSED */
1444 static void
1445 channel_post_auth_listener(Channel *c, fd_set *readset, fd_set *writeset)
1446 {
1447 Channel *nc;
1448 int newsock;
1449 struct sockaddr_storage addr;
1450 socklen_t addrlen;
1451
1452 if (FD_ISSET(c->sock, readset)) {
1453 addrlen = sizeof(addr);
1454 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1455 if (newsock < 0) {
1456 error("accept from auth socket: %.100s", strerror(errno));
1457 return;
1458 }
1459 nc = channel_new("accepted auth socket",
1460 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1461 c->local_window_max, c->local_maxpacket,
1462 0, "accepted auth socket", 1);
1463 if (compat20) {
1464 packet_start(SSH2_MSG_CHANNEL_OPEN);
1465 packet_put_cstring("auth-agent@openssh.com");
1466 packet_put_int(nc->self);
1467 packet_put_int(c->local_window_max);
1468 packet_put_int(c->local_maxpacket);
1469 } else {
1470 packet_start(SSH_SMSG_AGENT_OPEN);
1471 packet_put_int(nc->self);
1472 }
1473 packet_send();
1474 }
1475 }
1476
1477 /* ARGSUSED */
1478 static void
1479 channel_post_connecting(Channel *c, fd_set *readset, fd_set *writeset)
1480 {
1481 int err = 0, sock;
1482 socklen_t sz = sizeof(err);
1483
1484 if (FD_ISSET(c->sock, writeset)) {
1485 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) {
1486 err = errno;
1487 error("getsockopt SO_ERROR failed");
1488 }
1489 if (err == 0) {
1490 debug("channel %d: connected to %s port %d",
1491 c->self, c->connect_ctx.host, c->connect_ctx.port);
1492 channel_connect_ctx_free(&c->connect_ctx);
1493 c->type = SSH_CHANNEL_OPEN;
1494 if (compat20) {
1495 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1496 packet_put_int(c->remote_id);
1497 packet_put_int(c->self);
1498 packet_put_int(c->local_window);
1499 packet_put_int(c->local_maxpacket);
1500 } else {
1501 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1502 packet_put_int(c->remote_id);
1503 packet_put_int(c->self);
1504 }
1505 } else {
1506 debug("channel %d: connection failed: %s",
1507 c->self, strerror(err));
1508 /* Try next address, if any */
1509 if ((sock = connect_next(&c->connect_ctx)) > 0) {
1510 close(c->sock);
1511 c->sock = c->rfd = c->wfd = sock;
1512 channel_max_fd = channel_find_maxfd();
1513 return;
1514 }
1515 /* Exhausted all addresses */
1516 error("connect_to %.100s port %d: failed.",
1517 c->connect_ctx.host, c->connect_ctx.port);
1518 channel_connect_ctx_free(&c->connect_ctx);
1519 if (compat20) {
1520 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1521 packet_put_int(c->remote_id);
1522 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1523 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1524 packet_put_cstring(strerror(err));
1525 packet_put_cstring("");
1526 }
1527 } else {
1528 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1529 packet_put_int(c->remote_id);
1530 }
1531 chan_mark_dead(c);
1532 }
1533 packet_send();
1534 }
1535 }
1536
1537 /* ARGSUSED */
1538 static int
1539 channel_handle_rfd(Channel *c, fd_set *readset, fd_set *writeset)
1540 {
1541 char buf[CHAN_RBUF];
1542 int len, force;
1543
1544 force = c->isatty && c->detach_close && c->istate != CHAN_INPUT_CLOSED;
1545 if (c->rfd != -1 && (force || FD_ISSET(c->rfd, readset))) {
1546 errno = 0;
1547 len = read(c->rfd, buf, sizeof(buf));
1548 if (len < 0 && (errno == EINTR ||
1549 ((errno == EAGAIN || errno == EWOULDBLOCK) && !force)))
1550 return 1;
1551 #ifndef PTY_ZEROREAD
1552 if (len <= 0) {
1553 #else
1554 if ((!c->isatty && len <= 0) ||
1555 (c->isatty && (len < 0 || (len == 0 && errno != 0)))) {
1556 #endif
1557 debug2("channel %d: read<=0 rfd %d len %d",
1558 c->self, c->rfd, len);
1559 if (c->type != SSH_CHANNEL_OPEN) {
1560 debug2("channel %d: not open", c->self);
1561 chan_mark_dead(c);
1562 return -1;
1563 } else if (compat13) {
1564 buffer_clear(&c->output);
1565 c->type = SSH_CHANNEL_INPUT_DRAINING;
1566 debug2("channel %d: input draining.", c->self);
1567 } else {
1568 chan_read_failed(c);
1569 }
1570 return -1;
1571 }
1572 if (c->input_filter != NULL) {
1573 if (c->input_filter(c, buf, len) == -1) {
1574 debug2("channel %d: filter stops", c->self);
1575 chan_read_failed(c);
1576 }
1577 } else if (c->datagram) {
1578 buffer_put_string(&c->input, buf, len);
1579 } else {
1580 buffer_append(&c->input, buf, len);
1581 }
1582 }
1583 return 1;
1584 }
1585
1586 /* ARGSUSED */
1587 static int
1588 channel_handle_wfd(Channel *c, fd_set *readset, fd_set *writeset)
1589 {
1590 struct termios tio;
1591 u_char *data = NULL, *buf;
1592 u_int dlen;
1593 int len;
1594
1595 /* Send buffered output data to the socket. */
1596 if (c->wfd != -1 &&
1597 FD_ISSET(c->wfd, writeset) &&
1598 buffer_len(&c->output) > 0) {
1599 if (c->output_filter != NULL) {
1600 if ((buf = c->output_filter(c, &data, &dlen)) == NULL) {
1601 debug2("channel %d: filter stops", c->self);
1602 if (c->type != SSH_CHANNEL_OPEN)
1603 chan_mark_dead(c);
1604 else
1605 chan_write_failed(c);
1606 return -1;
1607 }
1608 } else if (c->datagram) {
1609 buf = data = buffer_get_string(&c->output, &dlen);
1610 } else {
1611 buf = data = buffer_ptr(&c->output);
1612 dlen = buffer_len(&c->output);
1613 }
1614
1615 if (c->datagram) {
1616 /* ignore truncated writes, datagrams might get lost */
1617 c->local_consumed += dlen + 4;
1618 len = write(c->wfd, buf, dlen);
1619 xfree(data);
1620 if (len < 0 && (errno == EINTR || errno == EAGAIN ||
1621 errno == EWOULDBLOCK))
1622 return 1;
1623 if (len <= 0) {
1624 if (c->type != SSH_CHANNEL_OPEN)
1625 chan_mark_dead(c);
1626 else
1627 chan_write_failed(c);
1628 return -1;
1629 }
1630 return 1;
1631 }
1632 #ifdef _AIX
1633 /* XXX: Later AIX versions can't push as much data to tty */
1634 if (compat20 && c->wfd_isatty)
1635 dlen = MIN(dlen, 8*1024);
1636 #endif
1637
1638 len = write(c->wfd, buf, dlen);
1639 if (len < 0 &&
1640 (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK))
1641 return 1;
1642 if (len <= 0) {
1643 if (c->type != SSH_CHANNEL_OPEN) {
1644 debug2("channel %d: not open", c->self);
1645 chan_mark_dead(c);
1646 return -1;
1647 } else if (compat13) {
1648 buffer_clear(&c->output);
1649 debug2("channel %d: input draining.", c->self);
1650 c->type = SSH_CHANNEL_INPUT_DRAINING;
1651 } else {
1652 chan_write_failed(c);
1653 }
1654 return -1;
1655 }
1656 if (compat20 && c->isatty && dlen >= 1 && buf[0] != '\r') {
1657 if (tcgetattr(c->wfd, &tio) == 0 &&
1658 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1659 /*
1660 * Simulate echo to reduce the impact of
1661 * traffic analysis. We need to match the
1662 * size of a SSH2_MSG_CHANNEL_DATA message
1663 * (4 byte channel id + buf)
1664 */
1665 packet_send_ignore(4 + len);
1666 packet_send();
1667 }
1668 }
1669 buffer_consume(&c->output, len);
1670 if (compat20 && len > 0) {
1671 c->local_consumed += len;
1672 }
1673 }
1674 return 1;
1675 }
1676
1677 static int
1678 channel_handle_efd(Channel *c, fd_set *readset, fd_set *writeset)
1679 {
1680 char buf[CHAN_RBUF];
1681 int len;
1682
1683 /** XXX handle drain efd, too */
1684 if (c->efd != -1) {
1685 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1686 FD_ISSET(c->efd, writeset) &&
1687 buffer_len(&c->extended) > 0) {
1688 len = write(c->efd, buffer_ptr(&c->extended),
1689 buffer_len(&c->extended));
1690 debug2("channel %d: written %d to efd %d",
1691 c->self, len, c->efd);
1692 if (len < 0 && (errno == EINTR || errno == EAGAIN ||
1693 errno == EWOULDBLOCK))
1694 return 1;
1695 if (len <= 0) {
1696 debug2("channel %d: closing write-efd %d",
1697 c->self, c->efd);
1698 channel_close_fd(&c->efd);
1699 } else {
1700 buffer_consume(&c->extended, len);
1701 c->local_consumed += len;
1702 }
1703 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
1704 (c->detach_close || FD_ISSET(c->efd, readset))) {
1705 len = read(c->efd, buf, sizeof(buf));
1706 debug2("channel %d: read %d from efd %d",
1707 c->self, len, c->efd);
1708 if (len < 0 && (errno == EINTR || ((errno == EAGAIN ||
1709 errno == EWOULDBLOCK) && !c->detach_close)))
1710 return 1;
1711 if (len <= 0) {
1712 debug2("channel %d: closing read-efd %d",
1713 c->self, c->efd);
1714 channel_close_fd(&c->efd);
1715 } else {
1716 buffer_append(&c->extended, buf, len);
1717 }
1718 }
1719 }
1720 return 1;
1721 }
1722
1723 /* ARGSUSED */
1724 static int
1725 channel_handle_ctl(Channel *c, fd_set *readset, fd_set *writeset)
1726 {
1727 char buf[16];
1728 int len;
1729
1730 /* Monitor control fd to detect if the slave client exits */
1731 if (c->ctl_fd != -1 && FD_ISSET(c->ctl_fd, readset)) {
1732 len = read(c->ctl_fd, buf, sizeof(buf));
1733 if (len < 0 &&
1734 (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK))
1735 return 1;
1736 if (len <= 0) {
1737 debug2("channel %d: ctl read<=0", c->self);
1738 if (c->type != SSH_CHANNEL_OPEN) {
1739 debug2("channel %d: not open", c->self);
1740 chan_mark_dead(c);
1741 return -1;
1742 } else {
1743 chan_read_failed(c);
1744 chan_write_failed(c);
1745 }
1746 return -1;
1747 } else
1748 fatal("%s: unexpected data on ctl fd", __func__);
1749 }
1750 return 1;
1751 }
1752
1753 static int
1754 channel_check_window(Channel *c)
1755 {
1756 if (c->type == SSH_CHANNEL_OPEN &&
1757 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1758 ((c->local_window_max - c->local_window >
1759 c->local_maxpacket*3) ||
1760 c->local_window < c->local_window_max/2) &&
1761 c->local_consumed > 0) {
1762 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1763 packet_put_int(c->remote_id);
1764 packet_put_int(c->local_consumed);
1765 packet_send();
1766 debug2("channel %d: window %d sent adjust %d",
1767 c->self, c->local_window,
1768 c->local_consumed);
1769 c->local_window += c->local_consumed;
1770 c->local_consumed = 0;
1771 }
1772 return 1;
1773 }
1774
1775 static void
1776 channel_post_open(Channel *c, fd_set *readset, fd_set *writeset)
1777 {
1778 if (c->delayed)
1779 return;
1780 channel_handle_rfd(c, readset, writeset);
1781 channel_handle_wfd(c, readset, writeset);
1782 if (!compat20)
1783 return;
1784 channel_handle_efd(c, readset, writeset);
1785 channel_handle_ctl(c, readset, writeset);
1786 channel_check_window(c);
1787 }
1788
1789 /* ARGSUSED */
1790 static void
1791 channel_post_output_drain_13(Channel *c, fd_set *readset, fd_set *writeset)
1792 {
1793 int len;
1794
1795 /* Send buffered output data to the socket. */
1796 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1797 len = write(c->sock, buffer_ptr(&c->output),
1798 buffer_len(&c->output));
1799 if (len <= 0)
1800 buffer_clear(&c->output);
1801 else
1802 buffer_consume(&c->output, len);
1803 }
1804 }
1805
1806 static void
1807 channel_handler_init_20(void)
1808 {
1809 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1810 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1811 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1812 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
1813 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1814 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1815 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1816 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1817
1818 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1819 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1820 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
1821 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1822 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1823 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1824 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1825 }
1826
1827 static void
1828 channel_handler_init_13(void)
1829 {
1830 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
1831 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
1832 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1833 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1834 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1835 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
1836 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1837 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1838 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1839
1840 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1841 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1842 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1843 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1844 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
1845 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1846 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1847 }
1848
1849 static void
1850 channel_handler_init_15(void)
1851 {
1852 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1853 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1854 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1855 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1856 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1857 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1858 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1859
1860 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1861 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1862 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1863 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1864 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1865 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1866 }
1867
1868 static void
1869 channel_handler_init(void)
1870 {
1871 int i;
1872
1873 for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
1874 channel_pre[i] = NULL;
1875 channel_post[i] = NULL;
1876 }
1877 if (compat20)
1878 channel_handler_init_20();
1879 else if (compat13)
1880 channel_handler_init_13();
1881 else
1882 channel_handler_init_15();
1883 }
1884
1885 /* gc dead channels */
1886 static void
1887 channel_garbage_collect(Channel *c)
1888 {
1889 if (c == NULL)
1890 return;
1891 if (c->detach_user != NULL) {
1892 if (!chan_is_dead(c, c->detach_close))
1893 return;
1894 debug2("channel %d: gc: notify user", c->self);
1895 c->detach_user(c->self, NULL);
1896 /* if we still have a callback */
1897 if (c->detach_user != NULL)
1898 return;
1899 debug2("channel %d: gc: user detached", c->self);
1900 }
1901 if (!chan_is_dead(c, 1))
1902 return;
1903 debug2("channel %d: garbage collecting", c->self);
1904 channel_free(c);
1905 }
1906
1907 static void
1908 channel_handler(chan_fn *ftab[], fd_set *readset, fd_set *writeset)
1909 {
1910 static int did_init = 0;
1911 u_int i;
1912 Channel *c;
1913
1914 if (!did_init) {
1915 channel_handler_init();
1916 did_init = 1;
1917 }
1918 for (i = 0; i < channels_alloc; i++) {
1919 c = channels[i];
1920 if (c == NULL)
1921 continue;
1922 if (ftab[c->type] != NULL)
1923 (*ftab[c->type])(c, readset, writeset);
1924 channel_garbage_collect(c);
1925 }
1926 }
1927
1928 /*
1929 * Allocate/update select bitmasks and add any bits relevant to channels in
1930 * select bitmasks.
1931 */
1932 void
1933 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
1934 u_int *nallocp, int rekeying)
1935 {
1936 u_int n, sz, nfdset;
1937
1938 n = MAX(*maxfdp, channel_max_fd);
1939
1940 nfdset = howmany(n+1, NFDBITS);
1941 /* Explicitly test here, because xrealloc isn't always called */
1942 if (nfdset && SIZE_T_MAX / nfdset < sizeof(fd_mask))
1943 fatal("channel_prepare_select: max_fd (%d) is too large", n);
1944 sz = nfdset * sizeof(fd_mask);
1945
1946 /* perhaps check sz < nalloc/2 and shrink? */
1947 if (*readsetp == NULL || sz > *nallocp) {
1948 *readsetp = xrealloc(*readsetp, nfdset, sizeof(fd_mask));
1949 *writesetp = xrealloc(*writesetp, nfdset, sizeof(fd_mask));
1950 *nallocp = sz;
1951 }
1952 *maxfdp = n;
1953 memset(*readsetp, 0, sz);
1954 memset(*writesetp, 0, sz);
1955
1956 if (!rekeying)
1957 channel_handler(channel_pre, *readsetp, *writesetp);
1958 }
1959
1960 /*
1961 * After select, perform any appropriate operations for channels which have
1962 * events pending.
1963 */
1964 void
1965 channel_after_select(fd_set *readset, fd_set *writeset)
1966 {
1967 channel_handler(channel_post, readset, writeset);
1968 }
1969
1970
1971 /* If there is data to send to the connection, enqueue some of it now. */
1972 void
1973 channel_output_poll(void)
1974 {
1975 Channel *c;
1976 u_int i, len;
1977
1978 for (i = 0; i < channels_alloc; i++) {
1979 c = channels[i];
1980 if (c == NULL)
1981 continue;
1982
1983 /*
1984 * We are only interested in channels that can have buffered
1985 * incoming data.
1986 */
1987 if (compat13) {
1988 if (c->type != SSH_CHANNEL_OPEN &&
1989 c->type != SSH_CHANNEL_INPUT_DRAINING)
1990 continue;
1991 } else {
1992 if (c->type != SSH_CHANNEL_OPEN)
1993 continue;
1994 }
1995 if (compat20 &&
1996 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
1997 /* XXX is this true? */
1998 debug3("channel %d: will not send data after close", c->self);
1999 continue;
2000 }
2001
2002 /* Get the amount of buffered data for this channel. */
2003 if ((c->istate == CHAN_INPUT_OPEN ||
2004 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
2005 (len = buffer_len(&c->input)) > 0) {
2006 if (c->datagram) {
2007 if (len > 0) {
2008 u_char *data;
2009 u_int dlen;
2010
2011 data = buffer_get_string(&c->input,
2012 &dlen);
2013 packet_start(SSH2_MSG_CHANNEL_DATA);
2014 packet_put_int(c->remote_id);
2015 packet_put_string(data, dlen);
2016 packet_send();
2017 c->remote_window -= dlen + 4;
2018 xfree(data);
2019 }
2020 continue;
2021 }
2022 /*
2023 * Send some data for the other side over the secure
2024 * connection.
2025 */
2026 if (compat20) {
2027 if (len > c->remote_window)
2028 len = c->remote_window;
2029 if (len > c->remote_maxpacket)
2030 len = c->remote_maxpacket;
2031 } else {
2032 if (packet_is_interactive()) {
2033 if (len > 1024)
2034 len = 512;
2035 } else {
2036 /* Keep the packets at reasonable size. */
2037 if (len > packet_get_maxsize()/2)
2038 len = packet_get_maxsize()/2;
2039 }
2040 }
2041 if (len > 0) {
2042 packet_start(compat20 ?
2043 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
2044 packet_put_int(c->remote_id);
2045 packet_put_string(buffer_ptr(&c->input), len);
2046 packet_send();
2047 buffer_consume(&c->input, len);
2048 c->remote_window -= len;
2049 }
2050 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
2051 if (compat13)
2052 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
2053 /*
2054 * input-buffer is empty and read-socket shutdown:
2055 * tell peer, that we will not send more data: send IEOF.
2056 * hack for extended data: delay EOF if EFD still in use.
2057 */
2058 if (CHANNEL_EFD_INPUT_ACTIVE(c))
2059 debug2("channel %d: ibuf_empty delayed efd %d/(%d)",
2060 c->self, c->efd, buffer_len(&c->extended));
2061 else
2062 chan_ibuf_empty(c);
2063 }
2064 /* Send extended data, i.e. stderr */
2065 if (compat20 &&
2066 !(c->flags & CHAN_EOF_SENT) &&
2067 c->remote_window > 0 &&
2068 (len = buffer_len(&c->extended)) > 0 &&
2069 c->extended_usage == CHAN_EXTENDED_READ) {
2070 debug2("channel %d: rwin %u elen %u euse %d",
2071 c->self, c->remote_window, buffer_len(&c->extended),
2072 c->extended_usage);
2073 if (len > c->remote_window)
2074 len = c->remote_window;
2075 if (len > c->remote_maxpacket)
2076 len = c->remote_maxpacket;
2077 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
2078 packet_put_int(c->remote_id);
2079 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
2080 packet_put_string(buffer_ptr(&c->extended), len);
2081 packet_send();
2082 buffer_consume(&c->extended, len);
2083 c->remote_window -= len;
2084 debug2("channel %d: sent ext data %d", c->self, len);
2085 }
2086 }
2087 }
2088
2089
2090 /* -- protocol input */
2091
2092 /* ARGSUSED */
2093 void
2094 channel_input_data(int type, u_int32_t seq, void *ctxt)
2095 {
2096 int id;
2097 char *data;
2098 u_int data_len;
2099 Channel *c;
2100
2101 /* Get the channel number and verify it. */
2102 id = packet_get_int();
2103 c = channel_lookup(id);
2104 if (c == NULL)
2105 packet_disconnect("Received data for nonexistent channel %d.", id);
2106
2107 /* Ignore any data for non-open channels (might happen on close) */
2108 if (c->type != SSH_CHANNEL_OPEN &&
2109 c->type != SSH_CHANNEL_X11_OPEN)
2110 return;
2111
2112 /* Get the data. */
2113 data = packet_get_string_ptr(&data_len);
2114
2115 /*
2116 * Ignore data for protocol > 1.3 if output end is no longer open.
2117 * For protocol 2 the sending side is reducing its window as it sends
2118 * data, so we must 'fake' consumption of the data in order to ensure
2119 * that window updates are sent back. Otherwise the connection might
2120 * deadlock.
2121 */
2122 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) {
2123 if (compat20) {
2124 c->local_window -= data_len;
2125 c->local_consumed += data_len;
2126 }
2127 return;
2128 }
2129
2130 if (compat20) {
2131 if (data_len > c->local_maxpacket) {
2132 logit("channel %d: rcvd big packet %d, maxpack %d",
2133 c->self, data_len, c->local_maxpacket);
2134 }
2135 if (data_len > c->local_window) {
2136 logit("channel %d: rcvd too much data %d, win %d",
2137 c->self, data_len, c->local_window);
2138 return;
2139 }
2140 c->local_window -= data_len;
2141 }
2142 if (c->datagram)
2143 buffer_put_string(&c->output, data, data_len);
2144 else
2145 buffer_append(&c->output, data, data_len);
2146 packet_check_eom();
2147 }
2148
2149 /* ARGSUSED */
2150 void
2151 channel_input_extended_data(int type, u_int32_t seq, void *ctxt)
2152 {
2153 int id;
2154 char *data;
2155 u_int data_len, tcode;
2156 Channel *c;
2157
2158 /* Get the channel number and verify it. */
2159 id = packet_get_int();
2160 c = channel_lookup(id);
2161
2162 if (c == NULL)
2163 packet_disconnect("Received extended_data for bad channel %d.", id);
2164 if (c->type != SSH_CHANNEL_OPEN) {
2165 logit("channel %d: ext data for non open", id);
2166 return;
2167 }
2168 if (c->flags & CHAN_EOF_RCVD) {
2169 if (datafellows & SSH_BUG_EXTEOF)
2170 debug("channel %d: accepting ext data after eof", id);
2171 else
2172 packet_disconnect("Received extended_data after EOF "
2173 "on channel %d.", id);
2174 }
2175 tcode = packet_get_int();
2176 if (c->efd == -1 ||
2177 c->extended_usage != CHAN_EXTENDED_WRITE ||
2178 tcode != SSH2_EXTENDED_DATA_STDERR) {
2179 logit("channel %d: bad ext data", c->self);
2180 return;
2181 }
2182 data = packet_get_string(&data_len);
2183 packet_check_eom();
2184 if (data_len > c->local_window) {
2185 logit("channel %d: rcvd too much extended_data %d, win %d",
2186 c->self, data_len, c->local_window);
2187 xfree(data);
2188 return;
2189 }
2190 debug2("channel %d: rcvd ext data %d", c->self, data_len);
2191 c->local_window -= data_len;
2192 buffer_append(&c->extended, data, data_len);
2193 xfree(data);
2194 }
2195
2196 /* ARGSUSED */
2197 void
2198 channel_input_ieof(int type, u_int32_t seq, void *ctxt)
2199 {
2200 int id;
2201 Channel *c;
2202
2203 id = packet_get_int();
2204 packet_check_eom();
2205 c = channel_lookup(id);
2206 if (c == NULL)
2207 packet_disconnect("Received ieof for nonexistent channel %d.", id);
2208 chan_rcvd_ieof(c);
2209
2210 /* XXX force input close */
2211 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) {
2212 debug("channel %d: FORCE input drain", c->self);
2213 c->istate = CHAN_INPUT_WAIT_DRAIN;
2214 if (buffer_len(&c->input) == 0)
2215 chan_ibuf_empty(c);
2216 }
2217
2218 }
2219
2220 /* ARGSUSED */
2221 void
2222 channel_input_close(int type, u_int32_t seq, void *ctxt)
2223 {
2224 int id;
2225 Channel *c;
2226
2227 id = packet_get_int();
2228 packet_check_eom();
2229 c = channel_lookup(id);
2230 if (c == NULL)
2231 packet_disconnect("Received close for nonexistent channel %d.", id);
2232
2233 /*
2234 * Send a confirmation that we have closed the channel and no more
2235 * data is coming for it.
2236 */
2237 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
2238 packet_put_int(c->remote_id);
2239 packet_send();
2240
2241 /*
2242 * If the channel is in closed state, we have sent a close request,
2243 * and the other side will eventually respond with a confirmation.
2244 * Thus, we cannot free the channel here, because then there would be
2245 * no-one to receive the confirmation. The channel gets freed when
2246 * the confirmation arrives.
2247 */
2248 if (c->type != SSH_CHANNEL_CLOSED) {
2249 /*
2250 * Not a closed channel - mark it as draining, which will
2251 * cause it to be freed later.
2252 */
2253 buffer_clear(&c->input);
2254 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
2255 }
2256 }
2257
2258 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
2259 /* ARGSUSED */
2260 void
2261 channel_input_oclose(int type, u_int32_t seq, void *ctxt)
2262 {
2263 int id = packet_get_int();
2264 Channel *c = channel_lookup(id);
2265
2266 packet_check_eom();
2267 if (c == NULL)
2268 packet_disconnect("Received oclose for nonexistent channel %d.", id);
2269 chan_rcvd_oclose(c);
2270 }
2271
2272 /* ARGSUSED */
2273 void
2274 channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt)
2275 {
2276 int id = packet_get_int();
2277 Channel *c = channel_lookup(id);
2278
2279 packet_check_eom();
2280 if (c == NULL)
2281 packet_disconnect("Received close confirmation for "
2282 "out-of-range channel %d.", id);
2283 if (c->type != SSH_CHANNEL_CLOSED)
2284 packet_disconnect("Received close confirmation for "
2285 "non-closed channel %d (type %d).", id, c->type);
2286 channel_free(c);
2287 }
2288
2289 /* ARGSUSED */
2290 void
2291 channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt)
2292 {
2293 int id, remote_id;
2294 Channel *c;
2295
2296 id = packet_get_int();
2297 c = channel_lookup(id);
2298
2299 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2300 packet_disconnect("Received open confirmation for "
2301 "non-opening channel %d.", id);
2302 remote_id = packet_get_int();
2303 /* Record the remote channel number and mark that the channel is now open. */
2304 c->remote_id = remote_id;
2305 c->type = SSH_CHANNEL_OPEN;
2306
2307 if (compat20) {
2308 c->remote_window = packet_get_int();
2309 c->remote_maxpacket = packet_get_int();
2310 if (c->open_confirm) {
2311 debug2("callback start");
2312 c->open_confirm(c->self, c->open_confirm_ctx);
2313 debug2("callback done");
2314 }
2315 debug2("channel %d: open confirm rwindow %u rmax %u", c->self,
2316 c->remote_window, c->remote_maxpacket);
2317 }
2318 packet_check_eom();
2319 }
2320
2321 static char *
2322 reason2txt(int reason)
2323 {
2324 switch (reason) {
2325 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
2326 return "administratively prohibited";
2327 case SSH2_OPEN_CONNECT_FAILED:
2328 return "connect failed";
2329 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
2330 return "unknown channel type";
2331 case SSH2_OPEN_RESOURCE_SHORTAGE:
2332 return "resource shortage";
2333 }
2334 return "unknown reason";
2335 }
2336
2337 /* ARGSUSED */
2338 void
2339 channel_input_open_failure(int type, u_int32_t seq, void *ctxt)
2340 {
2341 int id, reason;
2342 char *msg = NULL, *lang = NULL;
2343 Channel *c;
2344
2345 id = packet_get_int();
2346 c = channel_lookup(id);
2347
2348 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2349 packet_disconnect("Received open failure for "
2350 "non-opening channel %d.", id);
2351 if (compat20) {
2352 reason = packet_get_int();
2353 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
2354 msg = packet_get_string(NULL);
2355 lang = packet_get_string(NULL);
2356 }
2357 logit("channel %d: open failed: %s%s%s", id,
2358 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
2359 if (msg != NULL)
2360 xfree(msg);
2361 if (lang != NULL)
2362 xfree(lang);
2363 }
2364 packet_check_eom();
2365 /* Schedule the channel for cleanup/deletion. */
2366 chan_mark_dead(c);
2367 }
2368
2369 /* ARGSUSED */
2370 void
2371 channel_input_window_adjust(int type, u_int32_t seq, void *ctxt)
2372 {
2373 Channel *c;
2374 int id;
2375 u_int adjust;
2376
2377 if (!compat20)
2378 return;
2379
2380 /* Get the channel number and verify it. */
2381 id = packet_get_int();
2382 c = channel_lookup(id);
2383
2384 if (c == NULL) {
2385 logit("Received window adjust for non-open channel %d.", id);
2386 return;
2387 }
2388 adjust = packet_get_int();
2389 packet_check_eom();
2390 debug2("channel %d: rcvd adjust %u", id, adjust);
2391 c->remote_window += adjust;
2392 }
2393
2394 /* ARGSUSED */
2395 void
2396 channel_input_port_open(int type, u_int32_t seq, void *ctxt)
2397 {
2398 Channel *c = NULL;
2399 u_short host_port;
2400 char *host, *originator_string;
2401 int remote_id;
2402
2403 remote_id = packet_get_int();
2404 host = packet_get_string(NULL);
2405 host_port = packet_get_int();
2406
2407 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2408 originator_string = packet_get_string(NULL);
2409 } else {
2410 originator_string = xstrdup("unknown (remote did not supply name)");
2411 }
2412 packet_check_eom();
2413 c = channel_connect_to(host, host_port,
2414 "connected socket", originator_string);
2415 xfree(originator_string);
2416 xfree(host);
2417 if (c == NULL) {
2418 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2419 packet_put_int(remote_id);
2420 packet_send();
2421 } else
2422 c->remote_id = remote_id;
2423 }
2424
2425 /* ARGSUSED */
2426 void
2427 channel_input_status_confirm(int type, u_int32_t seq, void *ctxt)
2428 {
2429 Channel *c;
2430 struct channel_confirm *cc;
2431 int id;
2432
2433 /* Reset keepalive timeout */
2434 packet_set_alive_timeouts(0);
2435
2436 id = packet_get_int();
2437 packet_check_eom();
2438
2439 debug2("channel_input_status_confirm: type %d id %d", type, id);
2440
2441 if ((c = channel_lookup(id)) == NULL) {
2442 logit("channel_input_status_confirm: %d: unknown", id);
2443 return;
2444 }
2445 ;
2446 if ((cc = TAILQ_FIRST(&c->status_confirms)) == NULL)
2447 return;
2448 cc->cb(type, c, cc->ctx);
2449 TAILQ_REMOVE(&c->status_confirms, cc, entry);
2450 bzero(cc, sizeof(*cc));
2451 xfree(cc);
2452 }
2453
2454 /* -- tcp forwarding */
2455
2456 void
2457 channel_set_af(int af)
2458 {
2459 IPv4or6 = af;
2460 }
2461
2462 static int
2463 channel_setup_fwd_listener(int type, const char *listen_addr,
2464 u_short listen_port, int *allocated_listen_port,
2465 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2466 {
2467 Channel *c;
2468 int sock, r, success = 0, wildcard = 0, is_client;
2469 struct addrinfo hints, *ai, *aitop;
2470 const char *host, *addr;
2471 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2472 in_port_t *lport_p;
2473
2474 host = (type == SSH_CHANNEL_RPORT_LISTENER) ?
2475 listen_addr : host_to_connect;
2476 is_client = (type == SSH_CHANNEL_PORT_LISTENER);
2477
2478 if (host == NULL) {
2479 error("No forward host name.");
2480 return 0;
2481 }
2482 if (strlen(host) >= NI_MAXHOST) {
2483 error("Forward host name too long.");
2484 return 0;
2485 }
2486
2487 /*
2488 * Determine whether or not a port forward listens to loopback,
2489 * specified address or wildcard. On the client, a specified bind
2490 * address will always override gateway_ports. On the server, a
2491 * gateway_ports of 1 (``yes'') will override the client's
2492 * specification and force a wildcard bind, whereas a value of 2
2493 * (``clientspecified'') will bind to whatever address the client
2494 * asked for.
2495 *
2496 * Special-case listen_addrs are:
2497 *
2498 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR
2499 * "" (empty string), "*" -> wildcard v4/v6
2500 * "localhost" -> loopback v4/v6
2501 */
2502 addr = NULL;
2503 if (listen_addr == NULL) {
2504 /* No address specified: default to gateway_ports setting */
2505 if (gateway_ports)
2506 wildcard = 1;
2507 } else if (gateway_ports || is_client) {
2508 if (((datafellows & SSH_OLD_FORWARD_ADDR) &&
2509 strcmp(listen_addr, "0.0.0.0") == 0 && is_client == 0) ||
2510 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 ||
2511 (!is_client && gateway_ports == 1))
2512 wildcard = 1;
2513 else if (strcmp(listen_addr, "localhost") != 0)
2514 addr = listen_addr;
2515 }
2516
2517 debug3("channel_setup_fwd_listener: type %d wildcard %d addr %s",
2518 type, wildcard, (addr == NULL) ? "NULL" : addr);
2519
2520 /*
2521 * getaddrinfo returns a loopback address if the hostname is
2522 * set to NULL and hints.ai_flags is not AI_PASSIVE
2523 */
2524 memset(&hints, 0, sizeof(hints));
2525 hints.ai_family = IPv4or6;
2526 hints.ai_flags = wildcard ? AI_PASSIVE : 0;
2527 hints.ai_socktype = SOCK_STREAM;
2528 snprintf(strport, sizeof strport, "%d", listen_port);
2529 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) {
2530 if (addr == NULL) {
2531 /* This really shouldn't happen */
2532 packet_disconnect("getaddrinfo: fatal error: %s",
2533 ssh_gai_strerror(r));
2534 } else {
2535 error("channel_setup_fwd_listener: "
2536 "getaddrinfo(%.64s): %s", addr,
2537 ssh_gai_strerror(r));
2538 }
2539 return 0;
2540 }
2541 if (allocated_listen_port != NULL)
2542 *allocated_listen_port = 0;
2543 for (ai = aitop; ai; ai = ai->ai_next) {
2544 switch (ai->ai_family) {
2545 case AF_INET:
2546 lport_p = &((struct sockaddr_in *)ai->ai_addr)->
2547 sin_port;
2548 break;
2549 case AF_INET6:
2550 lport_p = &((struct sockaddr_in6 *)ai->ai_addr)->
2551 sin6_port;
2552 break;
2553 default:
2554 continue;
2555 }
2556 /*
2557 * If allocating a port for -R forwards, then use the
2558 * same port for all address families.
2559 */
2560 if (type == SSH_CHANNEL_RPORT_LISTENER && listen_port == 0 &&
2561 allocated_listen_port != NULL && *allocated_listen_port > 0)
2562 *lport_p = htons(*allocated_listen_port);
2563
2564 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2565 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2566 error("channel_setup_fwd_listener: getnameinfo failed");
2567 continue;
2568 }
2569 /* Create a port to listen for the host. */
2570 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2571 if (sock < 0) {
2572 /* this is no error since kernel may not support ipv6 */
2573 verbose("socket: %.100s", strerror(errno));
2574 continue;
2575 }
2576
2577 channel_set_reuseaddr(sock);
2578
2579 debug("Local forwarding listening on %s port %s.",
2580 ntop, strport);
2581
2582 /* Bind the socket to the address. */
2583 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2584 /* address can be in use ipv6 address is already bound */
2585 if (!ai->ai_next)
2586 error("bind: %.100s", strerror(errno));
2587 else
2588 verbose("bind: %.100s", strerror(errno));
2589
2590 close(sock);
2591 continue;
2592 }
2593 /* Start listening for connections on the socket. */
2594 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2595 error("listen: %.100s", strerror(errno));
2596 close(sock);
2597 continue;
2598 }
2599
2600 /*
2601 * listen_port == 0 requests a dynamically allocated port -
2602 * record what we got.
2603 */
2604 if (type == SSH_CHANNEL_RPORT_LISTENER && listen_port == 0 &&
2605 allocated_listen_port != NULL &&
2606 *allocated_listen_port == 0) {
2607 *allocated_listen_port = get_sock_port(sock, 1);
2608 debug("Allocated listen port %d",
2609 *allocated_listen_port);
2610 }
2611
2612 /* Allocate a channel number for the socket. */
2613 c = channel_new("port listener", type, sock, sock, -1,
2614 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2615 0, "port listener", 1);
2616 c->path = xstrdup(host);
2617 c->host_port = port_to_connect;
2618 c->listening_port = listen_port;
2619 success = 1;
2620 }
2621 if (success == 0)
2622 error("channel_setup_fwd_listener: cannot listen to port: %d",
2623 listen_port);
2624 freeaddrinfo(aitop);
2625 return success;
2626 }
2627
2628 int
2629 channel_cancel_rport_listener(const char *host, u_short port)
2630 {
2631 u_int i;
2632 int found = 0;
2633
2634 for (i = 0; i < channels_alloc; i++) {
2635 Channel *c = channels[i];
2636
2637 if (c != NULL && c->type == SSH_CHANNEL_RPORT_LISTENER &&
2638 strcmp(c->path, host) == 0 && c->listening_port == port) {
2639 debug2("%s: close channel %d", __func__, i);
2640 channel_free(c);
2641 found = 1;
2642 }
2643 }
2644
2645 return (found);
2646 }
2647
2648 /* protocol local port fwd, used by ssh (and sshd in v1) */
2649 int
2650 channel_setup_local_fwd_listener(const char *listen_host, u_short listen_port,
2651 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2652 {
2653 return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER,
2654 listen_host, listen_port, NULL, host_to_connect, port_to_connect,
2655 gateway_ports);
2656 }
2657
2658 /* protocol v2 remote port fwd, used by sshd */
2659 int
2660 channel_setup_remote_fwd_listener(const char *listen_address,
2661 u_short listen_port, int *allocated_listen_port, int gateway_ports)
2662 {
2663 return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER,
2664 listen_address, listen_port, allocated_listen_port,
2665 NULL, 0, gateway_ports);
2666 }
2667
2668 /*
2669 * Initiate forwarding of connections to port "port" on remote host through
2670 * the secure channel to host:port from local side.
2671 */
2672
2673 int
2674 channel_request_remote_forwarding(const char *listen_host, u_short listen_port,
2675 const char *host_to_connect, u_short port_to_connect)
2676 {
2677 int type, success = 0;
2678
2679 /* Record locally that connection to this host/port is permitted. */
2680 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2681 fatal("channel_request_remote_forwarding: too many forwards");
2682
2683 /* Send the forward request to the remote side. */
2684 if (compat20) {
2685 const char *address_to_bind;
2686 if (listen_host == NULL) {
2687 if (datafellows & SSH_BUG_RFWD_ADDR)
2688 address_to_bind = "127.0.0.1";
2689 else
2690 address_to_bind = "localhost";
2691 } else if (*listen_host == '\0' ||
2692 strcmp(listen_host, "*") == 0) {
2693 if (datafellows & SSH_BUG_RFWD_ADDR)
2694 address_to_bind = "0.0.0.0";
2695 else
2696 address_to_bind = "";
2697 } else
2698 address_to_bind = listen_host;
2699
2700 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2701 packet_put_cstring("tcpip-forward");
2702 packet_put_char(1); /* boolean: want reply */
2703 packet_put_cstring(address_to_bind);
2704 packet_put_int(listen_port);
2705 packet_send();
2706 packet_write_wait();
2707 /* Assume that server accepts the request */
2708 success = 1;
2709 } else {
2710 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2711 packet_put_int(listen_port);
2712 packet_put_cstring(host_to_connect);
2713 packet_put_int(port_to_connect);
2714 packet_send();
2715 packet_write_wait();
2716
2717 /* Wait for response from the remote side. */
2718 type = packet_read();
2719 switch (type) {
2720 case SSH_SMSG_SUCCESS:
2721 success = 1;
2722 break;
2723 case SSH_SMSG_FAILURE:
2724 break;
2725 default:
2726 /* Unknown packet */
2727 packet_disconnect("Protocol error for port forward request:"
2728 "received packet type %d.", type);
2729 }
2730 }
2731 if (success) {
2732 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2733 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2734 permitted_opens[num_permitted_opens].listen_port = listen_port;
2735 num_permitted_opens++;
2736 }
2737 return (success ? 0 : -1);
2738 }
2739
2740 /*
2741 * Request cancellation of remote forwarding of connection host:port from
2742 * local side.
2743 */
2744 void
2745 channel_request_rforward_cancel(const char *host, u_short port)
2746 {
2747 int i;
2748
2749 if (!compat20)
2750 return;
2751
2752 for (i = 0; i < num_permitted_opens; i++) {
2753 if (permitted_opens[i].host_to_connect != NULL &&
2754 permitted_opens[i].listen_port == port)
2755 break;
2756 }
2757 if (i >= num_permitted_opens) {
2758 debug("%s: requested forward not found", __func__);
2759 return;
2760 }
2761 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2762 packet_put_cstring("cancel-tcpip-forward");
2763 packet_put_char(0);
2764 packet_put_cstring(host == NULL ? "" : host);
2765 packet_put_int(port);
2766 packet_send();
2767
2768 permitted_opens[i].listen_port = 0;
2769 permitted_opens[i].port_to_connect = 0;
2770 xfree(permitted_opens[i].host_to_connect);
2771 permitted_opens[i].host_to_connect = NULL;
2772 }
2773
2774 /*
2775 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
2776 * listening for the port, and sends back a success reply (or disconnect
2777 * message if there was an error).
2778 */
2779 int
2780 channel_input_port_forward_request(int is_root, int gateway_ports)
2781 {
2782 u_short port, host_port;
2783 int success = 0;
2784 char *hostname;
2785
2786 /* Get arguments from the packet. */
2787 port = packet_get_int();
2788 hostname = packet_get_string(NULL);
2789 host_port = packet_get_int();
2790
2791 #ifndef HAVE_CYGWIN
2792 /*
2793 * Check that an unprivileged user is not trying to forward a
2794 * privileged port.
2795 */
2796 if (port < IPPORT_RESERVED && !is_root)
2797 packet_disconnect(
2798 "Requested forwarding of port %d but user is not root.",
2799 port);
2800 if (host_port == 0)
2801 packet_disconnect("Dynamic forwarding denied.");
2802 #endif
2803
2804 /* Initiate forwarding */
2805 success = channel_setup_local_fwd_listener(NULL, port, hostname,
2806 host_port, gateway_ports);
2807
2808 /* Free the argument string. */
2809 xfree(hostname);
2810
2811 return (success ? 0 : -1);
2812 }
2813
2814 /*
2815 * Permits opening to any host/port if permitted_opens[] is empty. This is
2816 * usually called by the server, because the user could connect to any port
2817 * anyway, and the server has no way to know but to trust the client anyway.
2818 */
2819 void
2820 channel_permit_all_opens(void)
2821 {
2822 if (num_permitted_opens == 0)
2823 all_opens_permitted = 1;
2824 }
2825
2826 void
2827 channel_add_permitted_opens(char *host, int port)
2828 {
2829 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2830 fatal("channel_add_permitted_opens: too many forwards");
2831 debug("allow port forwarding to host %s port %d", host, port);
2832
2833 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
2834 permitted_opens[num_permitted_opens].port_to_connect = port;
2835 num_permitted_opens++;
2836
2837 all_opens_permitted = 0;
2838 }
2839
2840 int
2841 channel_add_adm_permitted_opens(char *host, int port)
2842 {
2843 if (num_adm_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2844 fatal("channel_add_adm_permitted_opens: too many forwards");
2845 debug("config allows port forwarding to host %s port %d", host, port);
2846
2847 permitted_adm_opens[num_adm_permitted_opens].host_to_connect
2848 = xstrdup(host);
2849 permitted_adm_opens[num_adm_permitted_opens].port_to_connect = port;
2850 return ++num_adm_permitted_opens;
2851 }
2852
2853 void
2854 channel_clear_permitted_opens(void)
2855 {
2856 int i;
2857
2858 for (i = 0; i < num_permitted_opens; i++)
2859 if (permitted_opens[i].host_to_connect != NULL)
2860 xfree(permitted_opens[i].host_to_connect);
2861 num_permitted_opens = 0;
2862 }
2863
2864 void
2865 channel_clear_adm_permitted_opens(void)
2866 {
2867 int i;
2868
2869 for (i = 0; i < num_adm_permitted_opens; i++)
2870 if (permitted_adm_opens[i].host_to_connect != NULL)
2871 xfree(permitted_adm_opens[i].host_to_connect);
2872 num_adm_permitted_opens = 0;
2873 }
2874
2875 void
2876 channel_print_adm_permitted_opens(void)
2877 {
2878 int i;
2879
2880 printf("permitopen");
2881 if (num_adm_permitted_opens == 0) {
2882 printf(" any\n");
2883 return;
2884 }
2885 for (i = 0; i < num_adm_permitted_opens; i++)
2886 if (permitted_adm_opens[i].host_to_connect != NULL)
2887 printf(" %s:%d", permitted_adm_opens[i].host_to_connect,
2888 permitted_adm_opens[i].port_to_connect);
2889 printf("\n");
2890 }
2891
2892 /* Try to start non-blocking connect to next host in cctx list */
2893 static int
2894 connect_next(struct channel_connect *cctx)
2895 {
2896 int sock, saved_errno;
2897 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2898
2899 for (; cctx->ai; cctx->ai = cctx->ai->ai_next) {
2900 if (cctx->ai->ai_family != AF_INET &&
2901 cctx->ai->ai_family != AF_INET6)
2902 continue;
2903 if (getnameinfo(cctx->ai->ai_addr, cctx->ai->ai_addrlen,
2904 ntop, sizeof(ntop), strport, sizeof(strport),
2905 NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2906 error("connect_next: getnameinfo failed");
2907 continue;
2908 }
2909 if ((sock = socket(cctx->ai->ai_family, cctx->ai->ai_socktype,
2910 cctx->ai->ai_protocol)) == -1) {
2911 if (cctx->ai->ai_next == NULL)
2912 error("socket: %.100s", strerror(errno));
2913 else
2914 verbose("socket: %.100s", strerror(errno));
2915 continue;
2916 }
2917 if (set_nonblock(sock) == -1)
2918 fatal("%s: set_nonblock(%d)", __func__, sock);
2919 if (connect(sock, cctx->ai->ai_addr,
2920 cctx->ai->ai_addrlen) == -1 && errno != EINPROGRESS) {
2921 debug("connect_next: host %.100s ([%.100s]:%s): "
2922 "%.100s", cctx->host, ntop, strport,
2923 strerror(errno));
2924 saved_errno = errno;
2925 close(sock);
2926 errno = saved_errno;
2927 continue; /* fail -- try next */
2928 }
2929 debug("connect_next: host %.100s ([%.100s]:%s) "
2930 "in progress, fd=%d", cctx->host, ntop, strport, sock);
2931 cctx->ai = cctx->ai->ai_next;
2932 set_nodelay(sock);
2933 return sock;
2934 }
2935 return -1;
2936 }
2937
2938 static void
2939 channel_connect_ctx_free(struct channel_connect *cctx)
2940 {
2941 xfree(cctx->host);
2942 if (cctx->aitop)
2943 freeaddrinfo(cctx->aitop);
2944 bzero(cctx, sizeof(*cctx));
2945 cctx->host = NULL;
2946 cctx->ai = cctx->aitop = NULL;
2947 }
2948
2949 /* Return CONNECTING channel to remote host, port */
2950 static Channel *
2951 connect_to(const char *host, u_short port, char *ctype, char *rname)
2952 {
2953 struct addrinfo hints;
2954 int gaierr;
2955 int sock = -1;
2956 char strport[NI_MAXSERV];
2957 struct channel_connect cctx;
2958 Channel *c;
2959
2960 memset(&cctx, 0, sizeof(cctx));
2961 memset(&hints, 0, sizeof(hints));
2962 hints.ai_family = IPv4or6;
2963 hints.ai_socktype = SOCK_STREAM;
2964 snprintf(strport, sizeof strport, "%d", port);
2965 if ((gaierr = getaddrinfo(host, strport, &hints, &cctx.aitop)) != 0) {
2966 error("connect_to %.100s: unknown host (%s)", host,
2967 ssh_gai_strerror(gaierr));
2968 return NULL;
2969 }
2970
2971 cctx.host = xstrdup(host);
2972 cctx.port = port;
2973 cctx.ai = cctx.aitop;
2974
2975 if ((sock = connect_next(&cctx)) == -1) {
2976 error("connect to %.100s port %d failed: %s",
2977 host, port, strerror(errno));
2978 channel_connect_ctx_free(&cctx);
2979 return NULL;
2980 }
2981 c = channel_new(ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1,
2982 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1);
2983 c->connect_ctx = cctx;
2984 return c;
2985 }
2986
2987 Channel *
2988 channel_connect_by_listen_address(u_short listen_port, char *ctype, char *rname)
2989 {
2990 int i;
2991
2992 for (i = 0; i < num_permitted_opens; i++) {
2993 if (permitted_opens[i].host_to_connect != NULL &&
2994 permitted_opens[i].listen_port == listen_port) {
2995 return connect_to(
2996 permitted_opens[i].host_to_connect,
2997 permitted_opens[i].port_to_connect, ctype, rname);
2998 }
2999 }
3000 error("WARNING: Server requests forwarding for unknown listen_port %d",
3001 listen_port);
3002 return NULL;
3003 }
3004
3005 /* Check if connecting to that port is permitted and connect. */
3006 Channel *
3007 channel_connect_to(const char *host, u_short port, char *ctype, char *rname)
3008 {
3009 int i, permit, permit_adm = 1;
3010
3011 permit = all_opens_permitted;
3012 if (!permit) {
3013 for (i = 0; i < num_permitted_opens; i++)
3014 if (permitted_opens[i].host_to_connect != NULL &&
3015 permitted_opens[i].port_to_connect == port &&
3016 strcmp(permitted_opens[i].host_to_connect, host) == 0)
3017 permit = 1;
3018 }
3019
3020 if (num_adm_permitted_opens > 0) {
3021 permit_adm = 0;
3022 for (i = 0; i < num_adm_permitted_opens; i++)
3023 if (permitted_adm_opens[i].host_to_connect != NULL &&
3024 permitted_adm_opens[i].port_to_connect == port &&
3025 strcmp(permitted_adm_opens[i].host_to_connect, host)
3026 == 0)
3027 permit_adm = 1;
3028 }
3029
3030 if (!permit || !permit_adm) {
3031 logit("Received request to connect to host %.100s port %d, "
3032 "but the request was denied.", host, port);
3033 return NULL;
3034 }
3035 return connect_to(host, port, ctype, rname);
3036 }
3037
3038 void
3039 channel_send_window_changes(void)
3040 {
3041 u_int i;
3042 struct winsize ws;
3043
3044 for (i = 0; i < channels_alloc; i++) {
3045 if (channels[i] == NULL || !channels[i]->client_tty ||
3046 channels[i]->type != SSH_CHANNEL_OPEN)
3047 continue;
3048 if (ioctl(channels[i]->rfd, TIOCGWINSZ, &ws) < 0)
3049 continue;
3050 channel_request_start(i, "window-change", 0);
3051 packet_put_int((u_int)ws.ws_col);
3052 packet_put_int((u_int)ws.ws_row);
3053 packet_put_int((u_int)ws.ws_xpixel);
3054 packet_put_int((u_int)ws.ws_ypixel);
3055 packet_send();
3056 }
3057 }
3058
3059 /* -- X11 forwarding */
3060
3061 /*
3062 * Creates an internet domain socket for listening for X11 connections.
3063 * Returns 0 and a suitable display number for the DISPLAY variable
3064 * stored in display_numberp , or -1 if an error occurs.
3065 */
3066 int
3067 x11_create_display_inet(int x11_display_offset, int x11_use_localhost,
3068 int single_connection, u_int *display_numberp, int **chanids)
3069 {
3070 Channel *nc = NULL;
3071 int display_number, sock;
3072 u_short port;
3073 struct addrinfo hints, *ai, *aitop;
3074 char strport[NI_MAXSERV];
3075 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
3076
3077 if (chanids == NULL)
3078 return -1;
3079
3080 for (display_number = x11_display_offset;
3081 display_number < MAX_DISPLAYS;
3082 display_number++) {
3083 port = 6000 + display_number;
3084 memset(&hints, 0, sizeof(hints));
3085 hints.ai_family = IPv4or6;
3086 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE;
3087 hints.ai_socktype = SOCK_STREAM;
3088 snprintf(strport, sizeof strport, "%d", port);
3089 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
3090 error("getaddrinfo: %.100s", ssh_gai_strerror(gaierr));
3091 return -1;
3092 }
3093 for (ai = aitop; ai; ai = ai->ai_next) {
3094 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
3095 continue;
3096 sock = socket(ai->ai_family, ai->ai_socktype,
3097 ai->ai_protocol);
3098 if (sock < 0) {
3099 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
3100 error("socket: %.100s", strerror(errno));
3101 freeaddrinfo(aitop);
3102 return -1;
3103 } else {
3104 debug("x11_create_display_inet: Socket family %d not supported",
3105 ai->ai_family);
3106 continue;
3107 }
3108 }
3109 #ifdef IPV6_V6ONLY
3110 if (ai->ai_family == AF_INET6) {
3111 int on = 1;
3112 if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) < 0)
3113 error("setsockopt IPV6_V6ONLY: %.100s", strerror(errno));
3114 }
3115 #endif
3116 if (x11_use_localhost)
3117 channel_set_reuseaddr(sock);
3118 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
3119 debug2("bind port %d: %.100s", port, strerror(errno));
3120 close(sock);
3121
3122 for (n = 0; n < num_socks; n++) {
3123 close(socks[n]);
3124 }
3125 num_socks = 0;
3126 break;
3127 }
3128 socks[num_socks++] = sock;
3129 if (num_socks == NUM_SOCKS)
3130 break;
3131 }
3132 freeaddrinfo(aitop);
3133 if (num_socks > 0)
3134 break;
3135 }
3136 if (display_number >= MAX_DISPLAYS) {
3137 error("Failed to allocate internet-domain X11 display socket.");
3138 return -1;
3139 }
3140 /* Start listening for connections on the socket. */
3141 for (n = 0; n < num_socks; n++) {
3142 sock = socks[n];
3143 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
3144 error("listen: %.100s", strerror(errno));
3145 close(sock);
3146 return -1;
3147 }
3148 }
3149
3150 /* Allocate a channel for each socket. */
3151 *chanids = xcalloc(num_socks + 1, sizeof(**chanids));
3152 for (n = 0; n < num_socks; n++) {
3153 sock = socks[n];
3154 nc = channel_new("x11 listener",
3155 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
3156 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
3157 0, "X11 inet listener", 1);
3158 nc->single_connection = single_connection;
3159 (*chanids)[n] = nc->self;
3160 }
3161 (*chanids)[n] = -1;
3162
3163 /* Return the display number for the DISPLAY environment variable. */
3164 *display_numberp = display_number;
3165 return (0);
3166 }
3167
3168 static int
3169 connect_local_xsocket_path(const char *pathname)
3170 {
3171 int sock;
3172 struct sockaddr_un addr;
3173
3174 sock = socket(AF_UNIX, SOCK_STREAM, 0);
3175 if (sock < 0)
3176 error("socket: %.100s", strerror(errno));
3177 memset(&addr, 0, sizeof(addr));
3178 addr.sun_family = AF_UNIX;
3179 strlcpy(addr.sun_path, pathname, sizeof addr.sun_path);
3180 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0)
3181 return sock;
3182 close(sock);
3183 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
3184 return -1;
3185 }
3186
3187 static int
3188 connect_local_xsocket(u_int dnr)
3189 {
3190 char buf[1024];
3191 snprintf(buf, sizeof buf, _PATH_UNIX_X, dnr);
3192 return connect_local_xsocket_path(buf);
3193 }
3194
3195 int
3196 x11_connect_display(void)
3197 {
3198 u_int display_number;
3199 const char *display;
3200 char buf[1024], *cp;
3201 struct addrinfo hints, *ai, *aitop;
3202 char strport[NI_MAXSERV];
3203 int gaierr, sock = 0;
3204
3205 /* Try to open a socket for the local X server. */
3206 display = getenv("DISPLAY");
3207 if (!display) {
3208 error("DISPLAY not set.");
3209 return -1;
3210 }
3211 /*
3212 * Now we decode the value of the DISPLAY variable and make a
3213 * connection to the real X server.
3214 */
3215
3216 /* Check if the display is from launchd. */
3217 #ifdef __APPLE__
3218 if (strncmp(display, "/tmp/launch", 11) == 0) {
3219 sock = connect_local_xsocket_path(display);
3220 if (sock < 0)
3221 return -1;
3222
3223 /* OK, we now have a connection to the display. */
3224 return sock;
3225 }
3226 #endif
3227 /*
3228 * Check if it is a unix domain socket. Unix domain displays are in
3229 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
3230 */
3231 if (strncmp(display, "unix:", 5) == 0 ||
3232 display[0] == ':') {
3233 /* Connect to the unix domain socket. */
3234 if (sscanf(strrchr(display, ':') + 1, "%u", &display_number) != 1) {
3235 error("Could not parse display number from DISPLAY: %.100s",
3236 display);
3237 return -1;
3238 }
3239 /* Create a socket. */
3240 sock = connect_local_xsocket(display_number);
3241 if (sock < 0)
3242 return -1;
3243
3244 /* OK, we now have a connection to the display. */
3245 return sock;
3246 }
3247 /*
3248 * Connect to an inet socket. The DISPLAY value is supposedly
3249 * hostname:d[.s], where hostname may also be numeric IP address.
3250 */
3251 strlcpy(buf, display, sizeof(buf));
3252 cp = strchr(buf, ':');
3253 if (!cp) {
3254 error("Could not find ':' in DISPLAY: %.100s", display);
3255 return -1;
3256 }
3257 *cp = 0;
3258 /* buf now contains the host name. But first we parse the display number. */
3259 if (sscanf(cp + 1, "%u", &display_number) != 1) {
3260 error("Could not parse display number from DISPLAY: %.100s",
3261 display);
3262 return -1;
3263 }
3264
3265 /* Look up the host address */
3266 memset(&hints, 0, sizeof(hints));
3267 hints.ai_family = IPv4or6;
3268 hints.ai_socktype = SOCK_STREAM;
3269 snprintf(strport, sizeof strport, "%u", 6000 + display_number);
3270 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
3271 error("%.100s: unknown host. (%s)", buf,
3272 ssh_gai_strerror(gaierr));
3273 return -1;
3274 }
3275 for (ai = aitop; ai; ai = ai->ai_next) {
3276 /* Create a socket. */
3277 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
3278 if (sock < 0) {
3279 debug2("socket: %.100s", strerror(errno));
3280 continue;
3281 }
3282 /* Connect it to the display. */
3283 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
3284 debug2("connect %.100s port %u: %.100s", buf,
3285 6000 + display_number, strerror(errno));
3286 close(sock);
3287 continue;
3288 }
3289 /* Success */
3290 break;
3291 }
3292 freeaddrinfo(aitop);
3293 if (!ai) {
3294 error("connect %.100s port %u: %.100s", buf, 6000 + display_number,
3295 strerror(errno));
3296 return -1;
3297 }
3298 set_nodelay(sock);
3299 return sock;
3300 }
3301
3302 /*
3303 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
3304 * the remote channel number. We should do whatever we want, and respond
3305 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
3306 */
3307
3308 /* ARGSUSED */
3309 void
3310 x11_input_open(int type, u_int32_t seq, void *ctxt)
3311 {
3312 Channel *c = NULL;
3313 int remote_id, sock = 0;
3314 char *remote_host;
3315
3316 debug("Received X11 open request.");
3317
3318 remote_id = packet_get_int();
3319
3320 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
3321 remote_host = packet_get_string(NULL);
3322 } else {
3323 remote_host = xstrdup("unknown (remote did not supply name)");
3324 }
3325 packet_check_eom();
3326
3327 /* Obtain a connection to the real X display. */
3328 sock = x11_connect_display();
3329 if (sock != -1) {
3330 /* Allocate a channel for this connection. */
3331 c = channel_new("connected x11 socket",
3332 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
3333 remote_host, 1);
3334 c->remote_id = remote_id;
3335 c->force_drain = 1;
3336 }
3337 xfree(remote_host);
3338 if (c == NULL) {
3339 /* Send refusal to the remote host. */
3340 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3341 packet_put_int(remote_id);
3342 } else {
3343 /* Send a confirmation to the remote host. */
3344 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
3345 packet_put_int(remote_id);
3346 packet_put_int(c->self);
3347 }
3348 packet_send();
3349 }
3350
3351 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
3352 /* ARGSUSED */
3353 void
3354 deny_input_open(int type, u_int32_t seq, void *ctxt)
3355 {
3356 int rchan = packet_get_int();
3357
3358 switch (type) {
3359 case SSH_SMSG_AGENT_OPEN:
3360 error("Warning: ssh server tried agent forwarding.");
3361 break;
3362 case SSH_SMSG_X11_OPEN:
3363 error("Warning: ssh server tried X11 forwarding.");
3364 break;
3365 default:
3366 error("deny_input_open: type %d", type);
3367 break;
3368 }
3369 error("Warning: this is probably a break-in attempt by a malicious server.");
3370 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3371 packet_put_int(rchan);
3372 packet_send();
3373 }
3374
3375 /*
3376 * Requests forwarding of X11 connections, generates fake authentication
3377 * data, and enables authentication spoofing.
3378 * This should be called in the client only.
3379 */
3380 void
3381 x11_request_forwarding_with_spoofing(int client_session_id, const char *disp,
3382 const char *proto, const char *data)
3383 {
3384 u_int data_len = (u_int) strlen(data) / 2;
3385 u_int i, value;
3386 char *new_data;
3387 int screen_number;
3388 const char *cp;
3389 u_int32_t rnd = 0;
3390
3391 if (x11_saved_display == NULL)
3392 x11_saved_display = xstrdup(disp);
3393 else if (strcmp(disp, x11_saved_display) != 0) {
3394 error("x11_request_forwarding_with_spoofing: different "
3395 "$DISPLAY already forwarded");
3396 return;
3397 }
3398
3399 cp = strchr(disp, ':');
3400 if (cp)
3401 cp = strchr(cp, '.');
3402 if (cp)
3403 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL);
3404 else
3405 screen_number = 0;
3406
3407 if (x11_saved_proto == NULL) {
3408 /* Save protocol name. */
3409 x11_saved_proto = xstrdup(proto);
3410 /*
3411 * Extract real authentication data and generate fake data
3412 * of the same length.
3413 */
3414 x11_saved_data = xmalloc(data_len);
3415 x11_fake_data = xmalloc(data_len);
3416 for (i = 0; i < data_len; i++) {
3417 if (sscanf(data + 2 * i, "%2x", &value) != 1)
3418 fatal("x11_request_forwarding: bad "
3419 "authentication data: %.100s", data);
3420 if (i % 4 == 0)
3421 rnd = arc4random();
3422 x11_saved_data[i] = value;
3423 x11_fake_data[i] = rnd & 0xff;
3424 rnd >>= 8;
3425 }
3426 x11_saved_data_len = data_len;
3427 x11_fake_data_len = data_len;
3428 }
3429
3430 /* Convert the fake data into hex. */
3431 new_data = tohex(x11_fake_data, data_len);
3432
3433 /* Send the request packet. */
3434 if (compat20) {
3435 channel_request_start(client_session_id, "x11-req", 0);
3436 packet_put_char(0); /* XXX bool single connection */
3437 } else {
3438 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
3439 }
3440 packet_put_cstring(proto);
3441 packet_put_cstring(new_data);
3442 packet_put_int(screen_number);
3443 packet_send();
3444 packet_write_wait();
3445 xfree(new_data);
3446 }
3447
3448
3449 /* -- agent forwarding */
3450
3451 /* Sends a message to the server to request authentication fd forwarding. */
3452
3453 void
3454 auth_request_forwarding(void)
3455 {
3456 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
3457 packet_send();
3458 packet_write_wait();
3459 }
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