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- stevesk@cvs.openbsd.org 2006/07/25 02:01:34
[openssh-git.git] / channels.c
blob895c43f6a0e37d25c70ca5140ce3e931ffc1a2dd
1 /* $OpenBSD: channels.c,v 1.260 2006/07/22 20:48:22 stevesk 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/ioctl.h>
45 #include <sys/types.h>
46 #include <sys/un.h>
47 #include <sys/socket.h>
48
49 #include <netinet/in.h>
50 #include <arpa/inet.h>
51
52 #include <errno.h>
53 #include <netdb.h>
54 #include <string.h>
55 #include <termios.h>
56 #include <unistd.h>
57
58 #include "ssh.h"
59 #include "ssh1.h"
60 #include "ssh2.h"
61 #include "packet.h"
62 #include "xmalloc.h"
63 #include "log.h"
64 #include "misc.h"
65 #include "channels.h"
66 #include "compat.h"
67 #include "canohost.h"
68 #include "key.h"
69 #include "authfd.h"
70 #include "pathnames.h"
71 #include "bufaux.h"
72
73 /* -- channel core */
74
75 /*
76 * Pointer to an array containing all allocated channels. The array is
77 * dynamically extended as needed.
78 */
79 static Channel **channels = NULL;
80
81 /*
82 * Size of the channel array. All slots of the array must always be
83 * initialized (at least the type field); unused slots set to NULL
84 */
85 static u_int channels_alloc = 0;
86
87 /*
88 * Maximum file descriptor value used in any of the channels. This is
89 * updated in channel_new.
90 */
91 static int channel_max_fd = 0;
92
93
94 /* -- tcp forwarding */
95
96 /*
97 * Data structure for storing which hosts are permitted for forward requests.
98 * The local sides of any remote forwards are stored in this array to prevent
99 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local
100 * network (which might be behind a firewall).
101 */
102 typedef struct {
103 char *host_to_connect; /* Connect to 'host'. */
104 u_short port_to_connect; /* Connect to 'port'. */
105 u_short listen_port; /* Remote side should listen port number. */
106 } ForwardPermission;
107
108 /* List of all permitted host/port pairs to connect by the user. */
109 static ForwardPermission permitted_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
110
111 /* List of all permitted host/port pairs to connect by the admin. */
112 static ForwardPermission permitted_adm_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
113
114 /* Number of permitted host/port pairs in the array permitted by the user. */
115 static int num_permitted_opens = 0;
116
117 /* Number of permitted host/port pair in the array permitted by the admin. */
118 static int num_adm_permitted_opens = 0;
119
120 /*
121 * If this is true, all opens are permitted. This is the case on the server
122 * on which we have to trust the client anyway, and the user could do
123 * anything after logging in anyway.
124 */
125 static int all_opens_permitted = 0;
126
127
128 /* -- X11 forwarding */
129
130 /* Maximum number of fake X11 displays to try. */
131 #define MAX_DISPLAYS 1000
132
133 /* Saved X11 local (client) display. */
134 static char *x11_saved_display = NULL;
135
136 /* Saved X11 authentication protocol name. */
137 static char *x11_saved_proto = NULL;
138
139 /* Saved X11 authentication data. This is the real data. */
140 static char *x11_saved_data = NULL;
141 static u_int x11_saved_data_len = 0;
142
143 /*
144 * Fake X11 authentication data. This is what the server will be sending us;
145 * we should replace any occurrences of this by the real data.
146 */
147 static u_char *x11_fake_data = NULL;
148 static u_int x11_fake_data_len;
149
150
151 /* -- agent forwarding */
152
153 #define NUM_SOCKS 10
154
155 /* AF_UNSPEC or AF_INET or AF_INET6 */
156 static int IPv4or6 = AF_UNSPEC;
157
158 /* helper */
159 static void port_open_helper(Channel *c, char *rtype);
160
161 /* -- channel core */
162
163 Channel *
164 channel_by_id(int id)
165 {
166 Channel *c;
167
168 if (id < 0 || (u_int)id >= channels_alloc) {
169 logit("channel_by_id: %d: bad id", id);
170 return NULL;
171 }
172 c = channels[id];
173 if (c == NULL) {
174 logit("channel_by_id: %d: bad id: channel free", id);
175 return NULL;
176 }
177 return c;
178 }
179
180 /*
181 * Returns the channel if it is allowed to receive protocol messages.
182 * Private channels, like listening sockets, may not receive messages.
183 */
184 Channel *
185 channel_lookup(int id)
186 {
187 Channel *c;
188
189 if ((c = channel_by_id(id)) == NULL)
190 return (NULL);
191
192 switch (c->type) {
193 case SSH_CHANNEL_X11_OPEN:
194 case SSH_CHANNEL_LARVAL:
195 case SSH_CHANNEL_CONNECTING:
196 case SSH_CHANNEL_DYNAMIC:
197 case SSH_CHANNEL_OPENING:
198 case SSH_CHANNEL_OPEN:
199 case SSH_CHANNEL_INPUT_DRAINING:
200 case SSH_CHANNEL_OUTPUT_DRAINING:
201 return (c);
202 }
203 logit("Non-public channel %d, type %d.", id, c->type);
204 return (NULL);
205 }
206
207 /*
208 * Register filedescriptors for a channel, used when allocating a channel or
209 * when the channel consumer/producer is ready, e.g. shell exec'd
210 */
211 static void
212 channel_register_fds(Channel *c, int rfd, int wfd, int efd,
213 int extusage, int nonblock)
214 {
215 /* Update the maximum file descriptor value. */
216 channel_max_fd = MAX(channel_max_fd, rfd);
217 channel_max_fd = MAX(channel_max_fd, wfd);
218 channel_max_fd = MAX(channel_max_fd, efd);
219
220 /* XXX set close-on-exec -markus */
221
222 c->rfd = rfd;
223 c->wfd = wfd;
224 c->sock = (rfd == wfd) ? rfd : -1;
225 c->ctl_fd = -1; /* XXX: set elsewhere */
226 c->efd = efd;
227 c->extended_usage = extusage;
228
229 /* XXX ugly hack: nonblock is only set by the server */
230 if (nonblock && isatty(c->rfd)) {
231 debug2("channel %d: rfd %d isatty", c->self, c->rfd);
232 c->isatty = 1;
233 if (!isatty(c->wfd)) {
234 error("channel %d: wfd %d is not a tty?",
235 c->self, c->wfd);
236 }
237 } else {
238 c->isatty = 0;
239 }
240 c->wfd_isatty = isatty(c->wfd);
241
242 /* enable nonblocking mode */
243 if (nonblock) {
244 if (rfd != -1)
245 set_nonblock(rfd);
246 if (wfd != -1)
247 set_nonblock(wfd);
248 if (efd != -1)
249 set_nonblock(efd);
250 }
251 }
252
253 /*
254 * Allocate a new channel object and set its type and socket. This will cause
255 * remote_name to be freed.
256 */
257 Channel *
258 channel_new(char *ctype, int type, int rfd, int wfd, int efd,
259 u_int window, u_int maxpack, int extusage, char *remote_name, int nonblock)
260 {
261 int found;
262 u_int i;
263 Channel *c;
264
265 /* Do initial allocation if this is the first call. */
266 if (channels_alloc == 0) {
267 channels_alloc = 10;
268 channels = xcalloc(channels_alloc, sizeof(Channel *));
269 for (i = 0; i < channels_alloc; i++)
270 channels[i] = NULL;
271 }
272 /* Try to find a free slot where to put the new channel. */
273 for (found = -1, i = 0; i < channels_alloc; i++)
274 if (channels[i] == NULL) {
275 /* Found a free slot. */
276 found = (int)i;
277 break;
278 }
279 if (found < 0) {
280 /* There are no free slots. Take last+1 slot and expand the array. */
281 found = channels_alloc;
282 if (channels_alloc > 10000)
283 fatal("channel_new: internal error: channels_alloc %d "
284 "too big.", channels_alloc);
285 channels = xrealloc(channels, channels_alloc + 10,
286 sizeof(Channel *));
287 channels_alloc += 10;
288 debug2("channel: expanding %d", channels_alloc);
289 for (i = found; i < channels_alloc; i++)
290 channels[i] = NULL;
291 }
292 /* Initialize and return new channel. */
293 c = channels[found] = xcalloc(1, sizeof(Channel));
294 buffer_init(&c->input);
295 buffer_init(&c->output);
296 buffer_init(&c->extended);
297 c->ostate = CHAN_OUTPUT_OPEN;
298 c->istate = CHAN_INPUT_OPEN;
299 c->flags = 0;
300 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
301 c->self = found;
302 c->type = type;
303 c->ctype = ctype;
304 c->local_window = window;
305 c->local_window_max = window;
306 c->local_consumed = 0;
307 c->local_maxpacket = maxpack;
308 c->remote_id = -1;
309 c->remote_name = xstrdup(remote_name);
310 c->remote_window = 0;
311 c->remote_maxpacket = 0;
312 c->force_drain = 0;
313 c->single_connection = 0;
314 c->detach_user = NULL;
315 c->detach_close = 0;
316 c->confirm = NULL;
317 c->confirm_ctx = NULL;
318 c->input_filter = NULL;
319 c->output_filter = NULL;
320 debug("channel %d: new [%s]", found, remote_name);
321 return c;
322 }
323
324 static int
325 channel_find_maxfd(void)
326 {
327 u_int i;
328 int max = 0;
329 Channel *c;
330
331 for (i = 0; i < channels_alloc; i++) {
332 c = channels[i];
333 if (c != NULL) {
334 max = MAX(max, c->rfd);
335 max = MAX(max, c->wfd);
336 max = MAX(max, c->efd);
337 }
338 }
339 return max;
340 }
341
342 int
343 channel_close_fd(int *fdp)
344 {
345 int ret = 0, fd = *fdp;
346
347 if (fd != -1) {
348 ret = close(fd);
349 *fdp = -1;
350 if (fd == channel_max_fd)
351 channel_max_fd = channel_find_maxfd();
352 }
353 return ret;
354 }
355
356 /* Close all channel fd/socket. */
357 static void
358 channel_close_fds(Channel *c)
359 {
360 debug3("channel %d: close_fds r %d w %d e %d c %d",
361 c->self, c->rfd, c->wfd, c->efd, c->ctl_fd);
362
363 channel_close_fd(&c->sock);
364 channel_close_fd(&c->ctl_fd);
365 channel_close_fd(&c->rfd);
366 channel_close_fd(&c->wfd);
367 channel_close_fd(&c->efd);
368 }
369
370 /* Free the channel and close its fd/socket. */
371 void
372 channel_free(Channel *c)
373 {
374 char *s;
375 u_int i, n;
376
377 for (n = 0, i = 0; i < channels_alloc; i++)
378 if (channels[i])
379 n++;
380 debug("channel %d: free: %s, nchannels %u", c->self,
381 c->remote_name ? c->remote_name : "???", n);
382
383 s = channel_open_message();
384 debug3("channel %d: status: %s", c->self, s);
385 xfree(s);
386
387 if (c->sock != -1)
388 shutdown(c->sock, SHUT_RDWR);
389 if (c->ctl_fd != -1)
390 shutdown(c->ctl_fd, SHUT_RDWR);
391 channel_close_fds(c);
392 buffer_free(&c->input);
393 buffer_free(&c->output);
394 buffer_free(&c->extended);
395 if (c->remote_name) {
396 xfree(c->remote_name);
397 c->remote_name = NULL;
398 }
399 channels[c->self] = NULL;
400 xfree(c);
401 }
402
403 void
404 channel_free_all(void)
405 {
406 u_int i;
407
408 for (i = 0; i < channels_alloc; i++)
409 if (channels[i] != NULL)
410 channel_free(channels[i]);
411 }
412
413 /*
414 * Closes the sockets/fds of all channels. This is used to close extra file
415 * descriptors after a fork.
416 */
417 void
418 channel_close_all(void)
419 {
420 u_int i;
421
422 for (i = 0; i < channels_alloc; i++)
423 if (channels[i] != NULL)
424 channel_close_fds(channels[i]);
425 }
426
427 /*
428 * Stop listening to channels.
429 */
430 void
431 channel_stop_listening(void)
432 {
433 u_int i;
434 Channel *c;
435
436 for (i = 0; i < channels_alloc; i++) {
437 c = channels[i];
438 if (c != NULL) {
439 switch (c->type) {
440 case SSH_CHANNEL_AUTH_SOCKET:
441 case SSH_CHANNEL_PORT_LISTENER:
442 case SSH_CHANNEL_RPORT_LISTENER:
443 case SSH_CHANNEL_X11_LISTENER:
444 channel_close_fd(&c->sock);
445 channel_free(c);
446 break;
447 }
448 }
449 }
450 }
451
452 /*
453 * Returns true if no channel has too much buffered data, and false if one or
454 * more channel is overfull.
455 */
456 int
457 channel_not_very_much_buffered_data(void)
458 {
459 u_int i;
460 Channel *c;
461
462 for (i = 0; i < channels_alloc; i++) {
463 c = channels[i];
464 if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
465 #if 0
466 if (!compat20 &&
467 buffer_len(&c->input) > packet_get_maxsize()) {
468 debug2("channel %d: big input buffer %d",
469 c->self, buffer_len(&c->input));
470 return 0;
471 }
472 #endif
473 if (buffer_len(&c->output) > packet_get_maxsize()) {
474 debug2("channel %d: big output buffer %u > %u",
475 c->self, buffer_len(&c->output),
476 packet_get_maxsize());
477 return 0;
478 }
479 }
480 }
481 return 1;
482 }
483
484 /* Returns true if any channel is still open. */
485 int
486 channel_still_open(void)
487 {
488 u_int i;
489 Channel *c;
490
491 for (i = 0; i < channels_alloc; i++) {
492 c = channels[i];
493 if (c == NULL)
494 continue;
495 switch (c->type) {
496 case SSH_CHANNEL_X11_LISTENER:
497 case SSH_CHANNEL_PORT_LISTENER:
498 case SSH_CHANNEL_RPORT_LISTENER:
499 case SSH_CHANNEL_CLOSED:
500 case SSH_CHANNEL_AUTH_SOCKET:
501 case SSH_CHANNEL_DYNAMIC:
502 case SSH_CHANNEL_CONNECTING:
503 case SSH_CHANNEL_ZOMBIE:
504 continue;
505 case SSH_CHANNEL_LARVAL:
506 if (!compat20)
507 fatal("cannot happen: SSH_CHANNEL_LARVAL");
508 continue;
509 case SSH_CHANNEL_OPENING:
510 case SSH_CHANNEL_OPEN:
511 case SSH_CHANNEL_X11_OPEN:
512 return 1;
513 case SSH_CHANNEL_INPUT_DRAINING:
514 case SSH_CHANNEL_OUTPUT_DRAINING:
515 if (!compat13)
516 fatal("cannot happen: OUT_DRAIN");
517 return 1;
518 default:
519 fatal("channel_still_open: bad channel type %d", c->type);
520 /* NOTREACHED */
521 }
522 }
523 return 0;
524 }
525
526 /* Returns the id of an open channel suitable for keepaliving */
527 int
528 channel_find_open(void)
529 {
530 u_int i;
531 Channel *c;
532
533 for (i = 0; i < channels_alloc; i++) {
534 c = channels[i];
535 if (c == NULL || c->remote_id < 0)
536 continue;
537 switch (c->type) {
538 case SSH_CHANNEL_CLOSED:
539 case SSH_CHANNEL_DYNAMIC:
540 case SSH_CHANNEL_X11_LISTENER:
541 case SSH_CHANNEL_PORT_LISTENER:
542 case SSH_CHANNEL_RPORT_LISTENER:
543 case SSH_CHANNEL_OPENING:
544 case SSH_CHANNEL_CONNECTING:
545 case SSH_CHANNEL_ZOMBIE:
546 continue;
547 case SSH_CHANNEL_LARVAL:
548 case SSH_CHANNEL_AUTH_SOCKET:
549 case SSH_CHANNEL_OPEN:
550 case SSH_CHANNEL_X11_OPEN:
551 return i;
552 case SSH_CHANNEL_INPUT_DRAINING:
553 case SSH_CHANNEL_OUTPUT_DRAINING:
554 if (!compat13)
555 fatal("cannot happen: OUT_DRAIN");
556 return i;
557 default:
558 fatal("channel_find_open: bad channel type %d", c->type);
559 /* NOTREACHED */
560 }
561 }
562 return -1;
563 }
564
565
566 /*
567 * Returns a message describing the currently open forwarded connections,
568 * suitable for sending to the client. The message contains crlf pairs for
569 * newlines.
570 */
571 char *
572 channel_open_message(void)
573 {
574 Buffer buffer;
575 Channel *c;
576 char buf[1024], *cp;
577 u_int i;
578
579 buffer_init(&buffer);
580 snprintf(buf, sizeof buf, "The following connections are open:\r\n");
581 buffer_append(&buffer, buf, strlen(buf));
582 for (i = 0; i < channels_alloc; i++) {
583 c = channels[i];
584 if (c == NULL)
585 continue;
586 switch (c->type) {
587 case SSH_CHANNEL_X11_LISTENER:
588 case SSH_CHANNEL_PORT_LISTENER:
589 case SSH_CHANNEL_RPORT_LISTENER:
590 case SSH_CHANNEL_CLOSED:
591 case SSH_CHANNEL_AUTH_SOCKET:
592 case SSH_CHANNEL_ZOMBIE:
593 continue;
594 case SSH_CHANNEL_LARVAL:
595 case SSH_CHANNEL_OPENING:
596 case SSH_CHANNEL_CONNECTING:
597 case SSH_CHANNEL_DYNAMIC:
598 case SSH_CHANNEL_OPEN:
599 case SSH_CHANNEL_X11_OPEN:
600 case SSH_CHANNEL_INPUT_DRAINING:
601 case SSH_CHANNEL_OUTPUT_DRAINING:
602 snprintf(buf, sizeof buf,
603 " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d cfd %d)\r\n",
604 c->self, c->remote_name,
605 c->type, c->remote_id,
606 c->istate, buffer_len(&c->input),
607 c->ostate, buffer_len(&c->output),
608 c->rfd, c->wfd, c->ctl_fd);
609 buffer_append(&buffer, buf, strlen(buf));
610 continue;
611 default:
612 fatal("channel_open_message: bad channel type %d", c->type);
613 /* NOTREACHED */
614 }
615 }
616 buffer_append(&buffer, "\0", 1);
617 cp = xstrdup(buffer_ptr(&buffer));
618 buffer_free(&buffer);
619 return cp;
620 }
621
622 void
623 channel_send_open(int id)
624 {
625 Channel *c = channel_lookup(id);
626
627 if (c == NULL) {
628 logit("channel_send_open: %d: bad id", id);
629 return;
630 }
631 debug2("channel %d: send open", id);
632 packet_start(SSH2_MSG_CHANNEL_OPEN);
633 packet_put_cstring(c->ctype);
634 packet_put_int(c->self);
635 packet_put_int(c->local_window);
636 packet_put_int(c->local_maxpacket);
637 packet_send();
638 }
639
640 void
641 channel_request_start(int id, char *service, int wantconfirm)
642 {
643 Channel *c = channel_lookup(id);
644
645 if (c == NULL) {
646 logit("channel_request_start: %d: unknown channel id", id);
647 return;
648 }
649 debug2("channel %d: request %s confirm %d", id, service, wantconfirm);
650 packet_start(SSH2_MSG_CHANNEL_REQUEST);
651 packet_put_int(c->remote_id);
652 packet_put_cstring(service);
653 packet_put_char(wantconfirm);
654 }
655
656 void
657 channel_register_confirm(int id, channel_callback_fn *fn, void *ctx)
658 {
659 Channel *c = channel_lookup(id);
660
661 if (c == NULL) {
662 logit("channel_register_comfirm: %d: bad id", id);
663 return;
664 }
665 c->confirm = fn;
666 c->confirm_ctx = ctx;
667 }
668
669 void
670 channel_register_cleanup(int id, channel_callback_fn *fn, int do_close)
671 {
672 Channel *c = channel_by_id(id);
673
674 if (c == NULL) {
675 logit("channel_register_cleanup: %d: bad id", id);
676 return;
677 }
678 c->detach_user = fn;
679 c->detach_close = do_close;
680 }
681
682 void
683 channel_cancel_cleanup(int id)
684 {
685 Channel *c = channel_by_id(id);
686
687 if (c == NULL) {
688 logit("channel_cancel_cleanup: %d: bad id", id);
689 return;
690 }
691 c->detach_user = NULL;
692 c->detach_close = 0;
693 }
694
695 void
696 channel_register_filter(int id, channel_infilter_fn *ifn,
697 channel_outfilter_fn *ofn)
698 {
699 Channel *c = channel_lookup(id);
700
701 if (c == NULL) {
702 logit("channel_register_filter: %d: bad id", id);
703 return;
704 }
705 c->input_filter = ifn;
706 c->output_filter = ofn;
707 }
708
709 void
710 channel_set_fds(int id, int rfd, int wfd, int efd,
711 int extusage, int nonblock, u_int window_max)
712 {
713 Channel *c = channel_lookup(id);
714
715 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
716 fatal("channel_activate for non-larval channel %d.", id);
717 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
718 c->type = SSH_CHANNEL_OPEN;
719 c->local_window = c->local_window_max = window_max;
720 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
721 packet_put_int(c->remote_id);
722 packet_put_int(c->local_window);
723 packet_send();
724 }
725
726 /*
727 * 'channel_pre*' are called just before select() to add any bits relevant to
728 * channels in the select bitmasks.
729 */
730 /*
731 * 'channel_post*': perform any appropriate operations for channels which
732 * have events pending.
733 */
734 typedef void chan_fn(Channel *c, fd_set *readset, fd_set *writeset);
735 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
736 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
737
738 /* ARGSUSED */
739 static void
740 channel_pre_listener(Channel *c, fd_set *readset, fd_set *writeset)
741 {
742 FD_SET(c->sock, readset);
743 }
744
745 /* ARGSUSED */
746 static void
747 channel_pre_connecting(Channel *c, fd_set *readset, fd_set *writeset)
748 {
749 debug3("channel %d: waiting for connection", c->self);
750 FD_SET(c->sock, writeset);
751 }
752
753 static void
754 channel_pre_open_13(Channel *c, fd_set *readset, fd_set *writeset)
755 {
756 if (buffer_len(&c->input) < packet_get_maxsize())
757 FD_SET(c->sock, readset);
758 if (buffer_len(&c->output) > 0)
759 FD_SET(c->sock, writeset);
760 }
761
762 static void
763 channel_pre_open(Channel *c, fd_set *readset, fd_set *writeset)
764 {
765 u_int limit = compat20 ? c->remote_window : packet_get_maxsize();
766
767 if (c->istate == CHAN_INPUT_OPEN &&
768 limit > 0 &&
769 buffer_len(&c->input) < limit &&
770 buffer_check_alloc(&c->input, CHAN_RBUF))
771 FD_SET(c->rfd, readset);
772 if (c->ostate == CHAN_OUTPUT_OPEN ||
773 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
774 if (buffer_len(&c->output) > 0) {
775 FD_SET(c->wfd, writeset);
776 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
777 if (CHANNEL_EFD_OUTPUT_ACTIVE(c))
778 debug2("channel %d: obuf_empty delayed efd %d/(%d)",
779 c->self, c->efd, buffer_len(&c->extended));
780 else
781 chan_obuf_empty(c);
782 }
783 }
784 /** XXX check close conditions, too */
785 if (compat20 && c->efd != -1) {
786 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
787 buffer_len(&c->extended) > 0)
788 FD_SET(c->efd, writeset);
789 else if (!(c->flags & CHAN_EOF_SENT) &&
790 c->extended_usage == CHAN_EXTENDED_READ &&
791 buffer_len(&c->extended) < c->remote_window)
792 FD_SET(c->efd, readset);
793 }
794 /* XXX: What about efd? races? */
795 if (compat20 && c->ctl_fd != -1 &&
796 c->istate == CHAN_INPUT_OPEN && c->ostate == CHAN_OUTPUT_OPEN)
797 FD_SET(c->ctl_fd, readset);
798 }
799
800 /* ARGSUSED */
801 static void
802 channel_pre_input_draining(Channel *c, fd_set *readset, fd_set *writeset)
803 {
804 if (buffer_len(&c->input) == 0) {
805 packet_start(SSH_MSG_CHANNEL_CLOSE);
806 packet_put_int(c->remote_id);
807 packet_send();
808 c->type = SSH_CHANNEL_CLOSED;
809 debug2("channel %d: closing after input drain.", c->self);
810 }
811 }
812
813 /* ARGSUSED */
814 static void
815 channel_pre_output_draining(Channel *c, fd_set *readset, fd_set *writeset)
816 {
817 if (buffer_len(&c->output) == 0)
818 chan_mark_dead(c);
819 else
820 FD_SET(c->sock, writeset);
821 }
822
823 /*
824 * This is a special state for X11 authentication spoofing. An opened X11
825 * connection (when authentication spoofing is being done) remains in this
826 * state until the first packet has been completely read. The authentication
827 * data in that packet is then substituted by the real data if it matches the
828 * fake data, and the channel is put into normal mode.
829 * XXX All this happens at the client side.
830 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
831 */
832 static int
833 x11_open_helper(Buffer *b)
834 {
835 u_char *ucp;
836 u_int proto_len, data_len;
837
838 /* Check if the fixed size part of the packet is in buffer. */
839 if (buffer_len(b) < 12)
840 return 0;
841
842 /* Parse the lengths of variable-length fields. */
843 ucp = buffer_ptr(b);
844 if (ucp[0] == 0x42) { /* Byte order MSB first. */
845 proto_len = 256 * ucp[6] + ucp[7];
846 data_len = 256 * ucp[8] + ucp[9];
847 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
848 proto_len = ucp[6] + 256 * ucp[7];
849 data_len = ucp[8] + 256 * ucp[9];
850 } else {
851 debug2("Initial X11 packet contains bad byte order byte: 0x%x",
852 ucp[0]);
853 return -1;
854 }
855
856 /* Check if the whole packet is in buffer. */
857 if (buffer_len(b) <
858 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
859 return 0;
860
861 /* Check if authentication protocol matches. */
862 if (proto_len != strlen(x11_saved_proto) ||
863 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
864 debug2("X11 connection uses different authentication protocol.");
865 return -1;
866 }
867 /* Check if authentication data matches our fake data. */
868 if (data_len != x11_fake_data_len ||
869 memcmp(ucp + 12 + ((proto_len + 3) & ~3),
870 x11_fake_data, x11_fake_data_len) != 0) {
871 debug2("X11 auth data does not match fake data.");
872 return -1;
873 }
874 /* Check fake data length */
875 if (x11_fake_data_len != x11_saved_data_len) {
876 error("X11 fake_data_len %d != saved_data_len %d",
877 x11_fake_data_len, x11_saved_data_len);
878 return -1;
879 }
880 /*
881 * Received authentication protocol and data match
882 * our fake data. Substitute the fake data with real
883 * data.
884 */
885 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
886 x11_saved_data, x11_saved_data_len);
887 return 1;
888 }
889
890 static void
891 channel_pre_x11_open_13(Channel *c, fd_set *readset, fd_set *writeset)
892 {
893 int ret = x11_open_helper(&c->output);
894
895 if (ret == 1) {
896 /* Start normal processing for the channel. */
897 c->type = SSH_CHANNEL_OPEN;
898 channel_pre_open_13(c, readset, writeset);
899 } else if (ret == -1) {
900 /*
901 * We have received an X11 connection that has bad
902 * authentication information.
903 */
904 logit("X11 connection rejected because of wrong authentication.");
905 buffer_clear(&c->input);
906 buffer_clear(&c->output);
907 channel_close_fd(&c->sock);
908 c->sock = -1;
909 c->type = SSH_CHANNEL_CLOSED;
910 packet_start(SSH_MSG_CHANNEL_CLOSE);
911 packet_put_int(c->remote_id);
912 packet_send();
913 }
914 }
915
916 static void
917 channel_pre_x11_open(Channel *c, fd_set *readset, fd_set *writeset)
918 {
919 int ret = x11_open_helper(&c->output);
920
921 /* c->force_drain = 1; */
922
923 if (ret == 1) {
924 c->type = SSH_CHANNEL_OPEN;
925 channel_pre_open(c, readset, writeset);
926 } else if (ret == -1) {
927 logit("X11 connection rejected because of wrong authentication.");
928 debug2("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
929 chan_read_failed(c);
930 buffer_clear(&c->input);
931 chan_ibuf_empty(c);
932 buffer_clear(&c->output);
933 /* for proto v1, the peer will send an IEOF */
934 if (compat20)
935 chan_write_failed(c);
936 else
937 c->type = SSH_CHANNEL_OPEN;
938 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
939 }
940 }
941
942 /* try to decode a socks4 header */
943 /* ARGSUSED */
944 static int
945 channel_decode_socks4(Channel *c, fd_set *readset, fd_set *writeset)
946 {
947 char *p, *host;
948 u_int len, have, i, found;
949 char username[256];
950 struct {
951 u_int8_t version;
952 u_int8_t command;
953 u_int16_t dest_port;
954 struct in_addr dest_addr;
955 } s4_req, s4_rsp;
956
957 debug2("channel %d: decode socks4", c->self);
958
959 have = buffer_len(&c->input);
960 len = sizeof(s4_req);
961 if (have < len)
962 return 0;
963 p = buffer_ptr(&c->input);
964 for (found = 0, i = len; i < have; i++) {
965 if (p[i] == '\0') {
966 found = 1;
967 break;
968 }
969 if (i > 1024) {
970 /* the peer is probably sending garbage */
971 debug("channel %d: decode socks4: too long",
972 c->self);
973 return -1;
974 }
975 }
976 if (!found)
977 return 0;
978 buffer_get(&c->input, (char *)&s4_req.version, 1);
979 buffer_get(&c->input, (char *)&s4_req.command, 1);
980 buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
981 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
982 have = buffer_len(&c->input);
983 p = buffer_ptr(&c->input);
984 len = strlen(p);
985 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
986 if (len > have)
987 fatal("channel %d: decode socks4: len %d > have %d",
988 c->self, len, have);
989 strlcpy(username, p, sizeof(username));
990 buffer_consume(&c->input, len);
991 buffer_consume(&c->input, 1); /* trailing '\0' */
992
993 host = inet_ntoa(s4_req.dest_addr);
994 strlcpy(c->path, host, sizeof(c->path));
995 c->host_port = ntohs(s4_req.dest_port);
996
997 debug2("channel %d: dynamic request: socks4 host %s port %u command %u",
998 c->self, host, c->host_port, s4_req.command);
999
1000 if (s4_req.command != 1) {
1001 debug("channel %d: cannot handle: socks4 cn %d",
1002 c->self, s4_req.command);
1003 return -1;
1004 }
1005 s4_rsp.version = 0; /* vn: 0 for reply */
1006 s4_rsp.command = 90; /* cd: req granted */
1007 s4_rsp.dest_port = 0; /* ignored */
1008 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
1009 buffer_append(&c->output, &s4_rsp, sizeof(s4_rsp));
1010 return 1;
1011 }
1012
1013 /* try to decode a socks5 header */
1014 #define SSH_SOCKS5_AUTHDONE 0x1000
1015 #define SSH_SOCKS5_NOAUTH 0x00
1016 #define SSH_SOCKS5_IPV4 0x01
1017 #define SSH_SOCKS5_DOMAIN 0x03
1018 #define SSH_SOCKS5_IPV6 0x04
1019 #define SSH_SOCKS5_CONNECT 0x01
1020 #define SSH_SOCKS5_SUCCESS 0x00
1021
1022 /* ARGSUSED */
1023 static int
1024 channel_decode_socks5(Channel *c, fd_set *readset, fd_set *writeset)
1025 {
1026 struct {
1027 u_int8_t version;
1028 u_int8_t command;
1029 u_int8_t reserved;
1030 u_int8_t atyp;
1031 } s5_req, s5_rsp;
1032 u_int16_t dest_port;
1033 u_char *p, dest_addr[255+1];
1034 u_int have, need, i, found, nmethods, addrlen, af;
1035
1036 debug2("channel %d: decode socks5", c->self);
1037 p = buffer_ptr(&c->input);
1038 if (p[0] != 0x05)
1039 return -1;
1040 have = buffer_len(&c->input);
1041 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) {
1042 /* format: ver | nmethods | methods */
1043 if (have < 2)
1044 return 0;
1045 nmethods = p[1];
1046 if (have < nmethods + 2)
1047 return 0;
1048 /* look for method: "NO AUTHENTICATION REQUIRED" */
1049 for (found = 0, i = 2 ; i < nmethods + 2; i++) {
1050 if (p[i] == SSH_SOCKS5_NOAUTH ) {
1051 found = 1;
1052 break;
1053 }
1054 }
1055 if (!found) {
1056 debug("channel %d: method SSH_SOCKS5_NOAUTH not found",
1057 c->self);
1058 return -1;
1059 }
1060 buffer_consume(&c->input, nmethods + 2);
1061 buffer_put_char(&c->output, 0x05); /* version */
1062 buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH); /* method */
1063 FD_SET(c->sock, writeset);
1064 c->flags |= SSH_SOCKS5_AUTHDONE;
1065 debug2("channel %d: socks5 auth done", c->self);
1066 return 0; /* need more */
1067 }
1068 debug2("channel %d: socks5 post auth", c->self);
1069 if (have < sizeof(s5_req)+1)
1070 return 0; /* need more */
1071 memcpy(&s5_req, p, sizeof(s5_req));
1072 if (s5_req.version != 0x05 ||
1073 s5_req.command != SSH_SOCKS5_CONNECT ||
1074 s5_req.reserved != 0x00) {
1075 debug2("channel %d: only socks5 connect supported", c->self);
1076 return -1;
1077 }
1078 switch (s5_req.atyp){
1079 case SSH_SOCKS5_IPV4:
1080 addrlen = 4;
1081 af = AF_INET;
1082 break;
1083 case SSH_SOCKS5_DOMAIN:
1084 addrlen = p[sizeof(s5_req)];
1085 af = -1;
1086 break;
1087 case SSH_SOCKS5_IPV6:
1088 addrlen = 16;
1089 af = AF_INET6;
1090 break;
1091 default:
1092 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp);
1093 return -1;
1094 }
1095 need = sizeof(s5_req) + addrlen + 2;
1096 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1097 need++;
1098 if (have < need)
1099 return 0;
1100 buffer_consume(&c->input, sizeof(s5_req));
1101 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1102 buffer_consume(&c->input, 1); /* host string length */
1103 buffer_get(&c->input, (char *)&dest_addr, addrlen);
1104 buffer_get(&c->input, (char *)&dest_port, 2);
1105 dest_addr[addrlen] = '\0';
1106 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1107 strlcpy(c->path, (char *)dest_addr, sizeof(c->path));
1108 else if (inet_ntop(af, dest_addr, c->path, sizeof(c->path)) == NULL)
1109 return -1;
1110 c->host_port = ntohs(dest_port);
1111
1112 debug2("channel %d: dynamic request: socks5 host %s port %u command %u",
1113 c->self, c->path, c->host_port, s5_req.command);
1114
1115 s5_rsp.version = 0x05;
1116 s5_rsp.command = SSH_SOCKS5_SUCCESS;
1117 s5_rsp.reserved = 0; /* ignored */
1118 s5_rsp.atyp = SSH_SOCKS5_IPV4;
1119 ((struct in_addr *)&dest_addr)->s_addr = INADDR_ANY;
1120 dest_port = 0; /* ignored */
1121
1122 buffer_append(&c->output, &s5_rsp, sizeof(s5_rsp));
1123 buffer_append(&c->output, &dest_addr, sizeof(struct in_addr));
1124 buffer_append(&c->output, &dest_port, sizeof(dest_port));
1125 return 1;
1126 }
1127
1128 /* dynamic port forwarding */
1129 static void
1130 channel_pre_dynamic(Channel *c, fd_set *readset, fd_set *writeset)
1131 {
1132 u_char *p;
1133 u_int have;
1134 int ret;
1135
1136 have = buffer_len(&c->input);
1137 c->delayed = 0;
1138 debug2("channel %d: pre_dynamic: have %d", c->self, have);
1139 /* buffer_dump(&c->input); */
1140 /* check if the fixed size part of the packet is in buffer. */
1141 if (have < 3) {
1142 /* need more */
1143 FD_SET(c->sock, readset);
1144 return;
1145 }
1146 /* try to guess the protocol */
1147 p = buffer_ptr(&c->input);
1148 switch (p[0]) {
1149 case 0x04:
1150 ret = channel_decode_socks4(c, readset, writeset);
1151 break;
1152 case 0x05:
1153 ret = channel_decode_socks5(c, readset, writeset);
1154 break;
1155 default:
1156 ret = -1;
1157 break;
1158 }
1159 if (ret < 0) {
1160 chan_mark_dead(c);
1161 } else if (ret == 0) {
1162 debug2("channel %d: pre_dynamic: need more", c->self);
1163 /* need more */
1164 FD_SET(c->sock, readset);
1165 } else {
1166 /* switch to the next state */
1167 c->type = SSH_CHANNEL_OPENING;
1168 port_open_helper(c, "direct-tcpip");
1169 }
1170 }
1171
1172 /* This is our fake X11 server socket. */
1173 /* ARGSUSED */
1174 static void
1175 channel_post_x11_listener(Channel *c, fd_set *readset, fd_set *writeset)
1176 {
1177 Channel *nc;
1178 struct sockaddr addr;
1179 int newsock;
1180 socklen_t addrlen;
1181 char buf[16384], *remote_ipaddr;
1182 int remote_port;
1183
1184 if (FD_ISSET(c->sock, readset)) {
1185 debug("X11 connection requested.");
1186 addrlen = sizeof(addr);
1187 newsock = accept(c->sock, &addr, &addrlen);
1188 if (c->single_connection) {
1189 debug2("single_connection: closing X11 listener.");
1190 channel_close_fd(&c->sock);
1191 chan_mark_dead(c);
1192 }
1193 if (newsock < 0) {
1194 error("accept: %.100s", strerror(errno));
1195 return;
1196 }
1197 set_nodelay(newsock);
1198 remote_ipaddr = get_peer_ipaddr(newsock);
1199 remote_port = get_peer_port(newsock);
1200 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1201 remote_ipaddr, remote_port);
1202
1203 nc = channel_new("accepted x11 socket",
1204 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1205 c->local_window_max, c->local_maxpacket, 0, buf, 1);
1206 if (compat20) {
1207 packet_start(SSH2_MSG_CHANNEL_OPEN);
1208 packet_put_cstring("x11");
1209 packet_put_int(nc->self);
1210 packet_put_int(nc->local_window_max);
1211 packet_put_int(nc->local_maxpacket);
1212 /* originator ipaddr and port */
1213 packet_put_cstring(remote_ipaddr);
1214 if (datafellows & SSH_BUG_X11FWD) {
1215 debug2("ssh2 x11 bug compat mode");
1216 } else {
1217 packet_put_int(remote_port);
1218 }
1219 packet_send();
1220 } else {
1221 packet_start(SSH_SMSG_X11_OPEN);
1222 packet_put_int(nc->self);
1223 if (packet_get_protocol_flags() &
1224 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1225 packet_put_cstring(buf);
1226 packet_send();
1227 }
1228 xfree(remote_ipaddr);
1229 }
1230 }
1231
1232 static void
1233 port_open_helper(Channel *c, char *rtype)
1234 {
1235 int direct;
1236 char buf[1024];
1237 char *remote_ipaddr = get_peer_ipaddr(c->sock);
1238 int remote_port = get_peer_port(c->sock);
1239
1240 direct = (strcmp(rtype, "direct-tcpip") == 0);
1241
1242 snprintf(buf, sizeof buf,
1243 "%s: listening port %d for %.100s port %d, "
1244 "connect from %.200s port %d",
1245 rtype, c->listening_port, c->path, c->host_port,
1246 remote_ipaddr, remote_port);
1247
1248 xfree(c->remote_name);
1249 c->remote_name = xstrdup(buf);
1250
1251 if (compat20) {
1252 packet_start(SSH2_MSG_CHANNEL_OPEN);
1253 packet_put_cstring(rtype);
1254 packet_put_int(c->self);
1255 packet_put_int(c->local_window_max);
1256 packet_put_int(c->local_maxpacket);
1257 if (direct) {
1258 /* target host, port */
1259 packet_put_cstring(c->path);
1260 packet_put_int(c->host_port);
1261 } else {
1262 /* listen address, port */
1263 packet_put_cstring(c->path);
1264 packet_put_int(c->listening_port);
1265 }
1266 /* originator host and port */
1267 packet_put_cstring(remote_ipaddr);
1268 packet_put_int((u_int)remote_port);
1269 packet_send();
1270 } else {
1271 packet_start(SSH_MSG_PORT_OPEN);
1272 packet_put_int(c->self);
1273 packet_put_cstring(c->path);
1274 packet_put_int(c->host_port);
1275 if (packet_get_protocol_flags() &
1276 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1277 packet_put_cstring(c->remote_name);
1278 packet_send();
1279 }
1280 xfree(remote_ipaddr);
1281 }
1282
1283 static void
1284 channel_set_reuseaddr(int fd)
1285 {
1286 int on = 1;
1287
1288 /*
1289 * Set socket options.
1290 * Allow local port reuse in TIME_WAIT.
1291 */
1292 if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1)
1293 error("setsockopt SO_REUSEADDR fd %d: %s", fd, strerror(errno));
1294 }
1295
1296 /*
1297 * This socket is listening for connections to a forwarded TCP/IP port.
1298 */
1299 /* ARGSUSED */
1300 static void
1301 channel_post_port_listener(Channel *c, fd_set *readset, fd_set *writeset)
1302 {
1303 Channel *nc;
1304 struct sockaddr addr;
1305 int newsock, nextstate;
1306 socklen_t addrlen;
1307 char *rtype;
1308
1309 if (FD_ISSET(c->sock, readset)) {
1310 debug("Connection to port %d forwarding "
1311 "to %.100s port %d requested.",
1312 c->listening_port, c->path, c->host_port);
1313
1314 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1315 nextstate = SSH_CHANNEL_OPENING;
1316 rtype = "forwarded-tcpip";
1317 } else {
1318 if (c->host_port == 0) {
1319 nextstate = SSH_CHANNEL_DYNAMIC;
1320 rtype = "dynamic-tcpip";
1321 } else {
1322 nextstate = SSH_CHANNEL_OPENING;
1323 rtype = "direct-tcpip";
1324 }
1325 }
1326
1327 addrlen = sizeof(addr);
1328 newsock = accept(c->sock, &addr, &addrlen);
1329 if (newsock < 0) {
1330 error("accept: %.100s", strerror(errno));
1331 return;
1332 }
1333 set_nodelay(newsock);
1334 nc = channel_new(rtype, nextstate, newsock, newsock, -1,
1335 c->local_window_max, c->local_maxpacket, 0, rtype, 1);
1336 nc->listening_port = c->listening_port;
1337 nc->host_port = c->host_port;
1338 strlcpy(nc->path, c->path, sizeof(nc->path));
1339
1340 if (nextstate == SSH_CHANNEL_DYNAMIC) {
1341 /*
1342 * do not call the channel_post handler until
1343 * this flag has been reset by a pre-handler.
1344 * otherwise the FD_ISSET calls might overflow
1345 */
1346 nc->delayed = 1;
1347 } else {
1348 port_open_helper(nc, rtype);
1349 }
1350 }
1351 }
1352
1353 /*
1354 * This is the authentication agent socket listening for connections from
1355 * clients.
1356 */
1357 /* ARGSUSED */
1358 static void
1359 channel_post_auth_listener(Channel *c, fd_set *readset, fd_set *writeset)
1360 {
1361 Channel *nc;
1362 int newsock;
1363 struct sockaddr addr;
1364 socklen_t addrlen;
1365
1366 if (FD_ISSET(c->sock, readset)) {
1367 addrlen = sizeof(addr);
1368 newsock = accept(c->sock, &addr, &addrlen);
1369 if (newsock < 0) {
1370 error("accept from auth socket: %.100s", strerror(errno));
1371 return;
1372 }
1373 nc = channel_new("accepted auth socket",
1374 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1375 c->local_window_max, c->local_maxpacket,
1376 0, "accepted auth socket", 1);
1377 if (compat20) {
1378 packet_start(SSH2_MSG_CHANNEL_OPEN);
1379 packet_put_cstring("auth-agent@openssh.com");
1380 packet_put_int(nc->self);
1381 packet_put_int(c->local_window_max);
1382 packet_put_int(c->local_maxpacket);
1383 } else {
1384 packet_start(SSH_SMSG_AGENT_OPEN);
1385 packet_put_int(nc->self);
1386 }
1387 packet_send();
1388 }
1389 }
1390
1391 /* ARGSUSED */
1392 static void
1393 channel_post_connecting(Channel *c, fd_set *readset, fd_set *writeset)
1394 {
1395 int err = 0;
1396 socklen_t sz = sizeof(err);
1397
1398 if (FD_ISSET(c->sock, writeset)) {
1399 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) {
1400 err = errno;
1401 error("getsockopt SO_ERROR failed");
1402 }
1403 if (err == 0) {
1404 debug("channel %d: connected", c->self);
1405 c->type = SSH_CHANNEL_OPEN;
1406 if (compat20) {
1407 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1408 packet_put_int(c->remote_id);
1409 packet_put_int(c->self);
1410 packet_put_int(c->local_window);
1411 packet_put_int(c->local_maxpacket);
1412 } else {
1413 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1414 packet_put_int(c->remote_id);
1415 packet_put_int(c->self);
1416 }
1417 } else {
1418 debug("channel %d: not connected: %s",
1419 c->self, strerror(err));
1420 if (compat20) {
1421 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1422 packet_put_int(c->remote_id);
1423 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1424 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1425 packet_put_cstring(strerror(err));
1426 packet_put_cstring("");
1427 }
1428 } else {
1429 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1430 packet_put_int(c->remote_id);
1431 }
1432 chan_mark_dead(c);
1433 }
1434 packet_send();
1435 }
1436 }
1437
1438 /* ARGSUSED */
1439 static int
1440 channel_handle_rfd(Channel *c, fd_set *readset, fd_set *writeset)
1441 {
1442 char buf[CHAN_RBUF];
1443 int len;
1444
1445 if (c->rfd != -1 &&
1446 FD_ISSET(c->rfd, readset)) {
1447 errno = 0;
1448 len = read(c->rfd, buf, sizeof(buf));
1449 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1450 return 1;
1451 #ifndef PTY_ZEROREAD
1452 if (len <= 0) {
1453 #else
1454 if ((!c->isatty && len <= 0) ||
1455 (c->isatty && (len < 0 || (len == 0 && errno != 0)))) {
1456 #endif
1457 debug2("channel %d: read<=0 rfd %d len %d",
1458 c->self, c->rfd, len);
1459 if (c->type != SSH_CHANNEL_OPEN) {
1460 debug2("channel %d: not open", c->self);
1461 chan_mark_dead(c);
1462 return -1;
1463 } else if (compat13) {
1464 buffer_clear(&c->output);
1465 c->type = SSH_CHANNEL_INPUT_DRAINING;
1466 debug2("channel %d: input draining.", c->self);
1467 } else {
1468 chan_read_failed(c);
1469 }
1470 return -1;
1471 }
1472 if (c->input_filter != NULL) {
1473 if (c->input_filter(c, buf, len) == -1) {
1474 debug2("channel %d: filter stops", c->self);
1475 chan_read_failed(c);
1476 }
1477 } else if (c->datagram) {
1478 buffer_put_string(&c->input, buf, len);
1479 } else {
1480 buffer_append(&c->input, buf, len);
1481 }
1482 }
1483 return 1;
1484 }
1485
1486 /* ARGSUSED */
1487 static int
1488 channel_handle_wfd(Channel *c, fd_set *readset, fd_set *writeset)
1489 {
1490 struct termios tio;
1491 u_char *data = NULL, *buf;
1492 u_int dlen;
1493 int len;
1494
1495 /* Send buffered output data to the socket. */
1496 if (c->wfd != -1 &&
1497 FD_ISSET(c->wfd, writeset) &&
1498 buffer_len(&c->output) > 0) {
1499 if (c->output_filter != NULL) {
1500 if ((buf = c->output_filter(c, &data, &dlen)) == NULL) {
1501 debug2("channel %d: filter stops", c->self);
1502 if (c->type != SSH_CHANNEL_OPEN)
1503 chan_mark_dead(c);
1504 else
1505 chan_write_failed(c);
1506 return -1;
1507 }
1508 } else if (c->datagram) {
1509 buf = data = buffer_get_string(&c->output, &dlen);
1510 } else {
1511 buf = data = buffer_ptr(&c->output);
1512 dlen = buffer_len(&c->output);
1513 }
1514
1515 if (c->datagram) {
1516 /* ignore truncated writes, datagrams might get lost */
1517 c->local_consumed += dlen + 4;
1518 len = write(c->wfd, buf, dlen);
1519 xfree(data);
1520 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1521 return 1;
1522 if (len <= 0) {
1523 if (c->type != SSH_CHANNEL_OPEN)
1524 chan_mark_dead(c);
1525 else
1526 chan_write_failed(c);
1527 return -1;
1528 }
1529 return 1;
1530 }
1531 #ifdef _AIX
1532 /* XXX: Later AIX versions can't push as much data to tty */
1533 if (compat20 && c->wfd_isatty)
1534 dlen = MIN(dlen, 8*1024);
1535 #endif
1536
1537 len = write(c->wfd, buf, dlen);
1538 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1539 return 1;
1540 if (len <= 0) {
1541 if (c->type != SSH_CHANNEL_OPEN) {
1542 debug2("channel %d: not open", c->self);
1543 chan_mark_dead(c);
1544 return -1;
1545 } else if (compat13) {
1546 buffer_clear(&c->output);
1547 debug2("channel %d: input draining.", c->self);
1548 c->type = SSH_CHANNEL_INPUT_DRAINING;
1549 } else {
1550 chan_write_failed(c);
1551 }
1552 return -1;
1553 }
1554 if (compat20 && c->isatty && dlen >= 1 && buf[0] != '\r') {
1555 if (tcgetattr(c->wfd, &tio) == 0 &&
1556 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1557 /*
1558 * Simulate echo to reduce the impact of
1559 * traffic analysis. We need to match the
1560 * size of a SSH2_MSG_CHANNEL_DATA message
1561 * (4 byte channel id + buf)
1562 */
1563 packet_send_ignore(4 + len);
1564 packet_send();
1565 }
1566 }
1567 buffer_consume(&c->output, len);
1568 if (compat20 && len > 0) {
1569 c->local_consumed += len;
1570 }
1571 }
1572 return 1;
1573 }
1574
1575 static int
1576 channel_handle_efd(Channel *c, fd_set *readset, fd_set *writeset)
1577 {
1578 char buf[CHAN_RBUF];
1579 int len;
1580
1581 /** XXX handle drain efd, too */
1582 if (c->efd != -1) {
1583 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1584 FD_ISSET(c->efd, writeset) &&
1585 buffer_len(&c->extended) > 0) {
1586 len = write(c->efd, buffer_ptr(&c->extended),
1587 buffer_len(&c->extended));
1588 debug2("channel %d: written %d to efd %d",
1589 c->self, len, c->efd);
1590 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1591 return 1;
1592 if (len <= 0) {
1593 debug2("channel %d: closing write-efd %d",
1594 c->self, c->efd);
1595 channel_close_fd(&c->efd);
1596 } else {
1597 buffer_consume(&c->extended, len);
1598 c->local_consumed += len;
1599 }
1600 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
1601 FD_ISSET(c->efd, readset)) {
1602 len = read(c->efd, buf, sizeof(buf));
1603 debug2("channel %d: read %d from efd %d",
1604 c->self, len, c->efd);
1605 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1606 return 1;
1607 if (len <= 0) {
1608 debug2("channel %d: closing read-efd %d",
1609 c->self, c->efd);
1610 channel_close_fd(&c->efd);
1611 } else {
1612 buffer_append(&c->extended, buf, len);
1613 }
1614 }
1615 }
1616 return 1;
1617 }
1618
1619 /* ARGSUSED */
1620 static int
1621 channel_handle_ctl(Channel *c, fd_set *readset, fd_set *writeset)
1622 {
1623 char buf[16];
1624 int len;
1625
1626 /* Monitor control fd to detect if the slave client exits */
1627 if (c->ctl_fd != -1 && FD_ISSET(c->ctl_fd, readset)) {
1628 len = read(c->ctl_fd, buf, sizeof(buf));
1629 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1630 return 1;
1631 if (len <= 0) {
1632 debug2("channel %d: ctl read<=0", c->self);
1633 if (c->type != SSH_CHANNEL_OPEN) {
1634 debug2("channel %d: not open", c->self);
1635 chan_mark_dead(c);
1636 return -1;
1637 } else {
1638 chan_read_failed(c);
1639 chan_write_failed(c);
1640 }
1641 return -1;
1642 } else
1643 fatal("%s: unexpected data on ctl fd", __func__);
1644 }
1645 return 1;
1646 }
1647
1648 static int
1649 channel_check_window(Channel *c)
1650 {
1651 if (c->type == SSH_CHANNEL_OPEN &&
1652 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1653 c->local_window < c->local_window_max/2 &&
1654 c->local_consumed > 0) {
1655 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1656 packet_put_int(c->remote_id);
1657 packet_put_int(c->local_consumed);
1658 packet_send();
1659 debug2("channel %d: window %d sent adjust %d",
1660 c->self, c->local_window,
1661 c->local_consumed);
1662 c->local_window += c->local_consumed;
1663 c->local_consumed = 0;
1664 }
1665 return 1;
1666 }
1667
1668 static void
1669 channel_post_open(Channel *c, fd_set *readset, fd_set *writeset)
1670 {
1671 if (c->delayed)
1672 return;
1673 channel_handle_rfd(c, readset, writeset);
1674 channel_handle_wfd(c, readset, writeset);
1675 if (!compat20)
1676 return;
1677 channel_handle_efd(c, readset, writeset);
1678 channel_handle_ctl(c, readset, writeset);
1679 channel_check_window(c);
1680 }
1681
1682 /* ARGSUSED */
1683 static void
1684 channel_post_output_drain_13(Channel *c, fd_set *readset, fd_set *writeset)
1685 {
1686 int len;
1687
1688 /* Send buffered output data to the socket. */
1689 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1690 len = write(c->sock, buffer_ptr(&c->output),
1691 buffer_len(&c->output));
1692 if (len <= 0)
1693 buffer_clear(&c->output);
1694 else
1695 buffer_consume(&c->output, len);
1696 }
1697 }
1698
1699 static void
1700 channel_handler_init_20(void)
1701 {
1702 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1703 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1704 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1705 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
1706 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1707 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1708 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1709 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1710
1711 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1712 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1713 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
1714 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1715 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1716 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1717 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1718 }
1719
1720 static void
1721 channel_handler_init_13(void)
1722 {
1723 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
1724 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
1725 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1726 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1727 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1728 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
1729 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1730 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1731 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1732
1733 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1734 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1735 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1736 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1737 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
1738 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1739 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1740 }
1741
1742 static void
1743 channel_handler_init_15(void)
1744 {
1745 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1746 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1747 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1748 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1749 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1750 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1751 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1752
1753 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1754 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1755 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1756 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1757 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1758 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1759 }
1760
1761 static void
1762 channel_handler_init(void)
1763 {
1764 int i;
1765
1766 for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
1767 channel_pre[i] = NULL;
1768 channel_post[i] = NULL;
1769 }
1770 if (compat20)
1771 channel_handler_init_20();
1772 else if (compat13)
1773 channel_handler_init_13();
1774 else
1775 channel_handler_init_15();
1776 }
1777
1778 /* gc dead channels */
1779 static void
1780 channel_garbage_collect(Channel *c)
1781 {
1782 if (c == NULL)
1783 return;
1784 if (c->detach_user != NULL) {
1785 if (!chan_is_dead(c, c->detach_close))
1786 return;
1787 debug2("channel %d: gc: notify user", c->self);
1788 c->detach_user(c->self, NULL);
1789 /* if we still have a callback */
1790 if (c->detach_user != NULL)
1791 return;
1792 debug2("channel %d: gc: user detached", c->self);
1793 }
1794 if (!chan_is_dead(c, 1))
1795 return;
1796 debug2("channel %d: garbage collecting", c->self);
1797 channel_free(c);
1798 }
1799
1800 static void
1801 channel_handler(chan_fn *ftab[], fd_set *readset, fd_set *writeset)
1802 {
1803 static int did_init = 0;
1804 u_int i;
1805 Channel *c;
1806
1807 if (!did_init) {
1808 channel_handler_init();
1809 did_init = 1;
1810 }
1811 for (i = 0; i < channels_alloc; i++) {
1812 c = channels[i];
1813 if (c == NULL)
1814 continue;
1815 if (ftab[c->type] != NULL)
1816 (*ftab[c->type])(c, readset, writeset);
1817 channel_garbage_collect(c);
1818 }
1819 }
1820
1821 /*
1822 * Allocate/update select bitmasks and add any bits relevant to channels in
1823 * select bitmasks.
1824 */
1825 void
1826 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
1827 u_int *nallocp, int rekeying)
1828 {
1829 u_int n, sz, nfdset;
1830
1831 n = MAX(*maxfdp, channel_max_fd);
1832
1833 nfdset = howmany(n+1, NFDBITS);
1834 /* Explicitly test here, because xrealloc isn't always called */
1835 if (nfdset && SIZE_T_MAX / nfdset < sizeof(fd_mask))
1836 fatal("channel_prepare_select: max_fd (%d) is too large", n);
1837 sz = nfdset * sizeof(fd_mask);
1838
1839 /* perhaps check sz < nalloc/2 and shrink? */
1840 if (*readsetp == NULL || sz > *nallocp) {
1841 *readsetp = xrealloc(*readsetp, nfdset, sizeof(fd_mask));
1842 *writesetp = xrealloc(*writesetp, nfdset, sizeof(fd_mask));
1843 *nallocp = sz;
1844 }
1845 *maxfdp = n;
1846 memset(*readsetp, 0, sz);
1847 memset(*writesetp, 0, sz);
1848
1849 if (!rekeying)
1850 channel_handler(channel_pre, *readsetp, *writesetp);
1851 }
1852
1853 /*
1854 * After select, perform any appropriate operations for channels which have
1855 * events pending.
1856 */
1857 void
1858 channel_after_select(fd_set *readset, fd_set *writeset)
1859 {
1860 channel_handler(channel_post, readset, writeset);
1861 }
1862
1863
1864 /* If there is data to send to the connection, enqueue some of it now. */
1865 void
1866 channel_output_poll(void)
1867 {
1868 Channel *c;
1869 u_int i, len;
1870
1871 for (i = 0; i < channels_alloc; i++) {
1872 c = channels[i];
1873 if (c == NULL)
1874 continue;
1875
1876 /*
1877 * We are only interested in channels that can have buffered
1878 * incoming data.
1879 */
1880 if (compat13) {
1881 if (c->type != SSH_CHANNEL_OPEN &&
1882 c->type != SSH_CHANNEL_INPUT_DRAINING)
1883 continue;
1884 } else {
1885 if (c->type != SSH_CHANNEL_OPEN)
1886 continue;
1887 }
1888 if (compat20 &&
1889 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
1890 /* XXX is this true? */
1891 debug3("channel %d: will not send data after close", c->self);
1892 continue;
1893 }
1894
1895 /* Get the amount of buffered data for this channel. */
1896 if ((c->istate == CHAN_INPUT_OPEN ||
1897 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
1898 (len = buffer_len(&c->input)) > 0) {
1899 if (c->datagram) {
1900 if (len > 0) {
1901 u_char *data;
1902 u_int dlen;
1903
1904 data = buffer_get_string(&c->input,
1905 &dlen);
1906 packet_start(SSH2_MSG_CHANNEL_DATA);
1907 packet_put_int(c->remote_id);
1908 packet_put_string(data, dlen);
1909 packet_send();
1910 c->remote_window -= dlen + 4;
1911 xfree(data);
1912 }
1913 continue;
1914 }
1915 /*
1916 * Send some data for the other side over the secure
1917 * connection.
1918 */
1919 if (compat20) {
1920 if (len > c->remote_window)
1921 len = c->remote_window;
1922 if (len > c->remote_maxpacket)
1923 len = c->remote_maxpacket;
1924 } else {
1925 if (packet_is_interactive()) {
1926 if (len > 1024)
1927 len = 512;
1928 } else {
1929 /* Keep the packets at reasonable size. */
1930 if (len > packet_get_maxsize()/2)
1931 len = packet_get_maxsize()/2;
1932 }
1933 }
1934 if (len > 0) {
1935 packet_start(compat20 ?
1936 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
1937 packet_put_int(c->remote_id);
1938 packet_put_string(buffer_ptr(&c->input), len);
1939 packet_send();
1940 buffer_consume(&c->input, len);
1941 c->remote_window -= len;
1942 }
1943 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1944 if (compat13)
1945 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
1946 /*
1947 * input-buffer is empty and read-socket shutdown:
1948 * tell peer, that we will not send more data: send IEOF.
1949 * hack for extended data: delay EOF if EFD still in use.
1950 */
1951 if (CHANNEL_EFD_INPUT_ACTIVE(c))
1952 debug2("channel %d: ibuf_empty delayed efd %d/(%d)",
1953 c->self, c->efd, buffer_len(&c->extended));
1954 else
1955 chan_ibuf_empty(c);
1956 }
1957 /* Send extended data, i.e. stderr */
1958 if (compat20 &&
1959 !(c->flags & CHAN_EOF_SENT) &&
1960 c->remote_window > 0 &&
1961 (len = buffer_len(&c->extended)) > 0 &&
1962 c->extended_usage == CHAN_EXTENDED_READ) {
1963 debug2("channel %d: rwin %u elen %u euse %d",
1964 c->self, c->remote_window, buffer_len(&c->extended),
1965 c->extended_usage);
1966 if (len > c->remote_window)
1967 len = c->remote_window;
1968 if (len > c->remote_maxpacket)
1969 len = c->remote_maxpacket;
1970 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
1971 packet_put_int(c->remote_id);
1972 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
1973 packet_put_string(buffer_ptr(&c->extended), len);
1974 packet_send();
1975 buffer_consume(&c->extended, len);
1976 c->remote_window -= len;
1977 debug2("channel %d: sent ext data %d", c->self, len);
1978 }
1979 }
1980 }
1981
1982
1983 /* -- protocol input */
1984
1985 /* ARGSUSED */
1986 void
1987 channel_input_data(int type, u_int32_t seq, void *ctxt)
1988 {
1989 int id;
1990 char *data;
1991 u_int data_len;
1992 Channel *c;
1993
1994 /* Get the channel number and verify it. */
1995 id = packet_get_int();
1996 c = channel_lookup(id);
1997 if (c == NULL)
1998 packet_disconnect("Received data for nonexistent channel %d.", id);
1999
2000 /* Ignore any data for non-open channels (might happen on close) */
2001 if (c->type != SSH_CHANNEL_OPEN &&
2002 c->type != SSH_CHANNEL_X11_OPEN)
2003 return;
2004
2005 /* Get the data. */
2006 data = packet_get_string(&data_len);
2007
2008 /*
2009 * Ignore data for protocol > 1.3 if output end is no longer open.
2010 * For protocol 2 the sending side is reducing its window as it sends
2011 * data, so we must 'fake' consumption of the data in order to ensure
2012 * that window updates are sent back. Otherwise the connection might
2013 * deadlock.
2014 */
2015 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) {
2016 if (compat20) {
2017 c->local_window -= data_len;
2018 c->local_consumed += data_len;
2019 }
2020 xfree(data);
2021 return;
2022 }
2023
2024 if (compat20) {
2025 if (data_len > c->local_maxpacket) {
2026 logit("channel %d: rcvd big packet %d, maxpack %d",
2027 c->self, data_len, c->local_maxpacket);
2028 }
2029 if (data_len > c->local_window) {
2030 logit("channel %d: rcvd too much data %d, win %d",
2031 c->self, data_len, c->local_window);
2032 xfree(data);
2033 return;
2034 }
2035 c->local_window -= data_len;
2036 }
2037 packet_check_eom();
2038 if (c->datagram)
2039 buffer_put_string(&c->output, data, data_len);
2040 else
2041 buffer_append(&c->output, data, data_len);
2042 xfree(data);
2043 }
2044
2045 /* ARGSUSED */
2046 void
2047 channel_input_extended_data(int type, u_int32_t seq, void *ctxt)
2048 {
2049 int id;
2050 char *data;
2051 u_int data_len, tcode;
2052 Channel *c;
2053
2054 /* Get the channel number and verify it. */
2055 id = packet_get_int();
2056 c = channel_lookup(id);
2057
2058 if (c == NULL)
2059 packet_disconnect("Received extended_data for bad channel %d.", id);
2060 if (c->type != SSH_CHANNEL_OPEN) {
2061 logit("channel %d: ext data for non open", id);
2062 return;
2063 }
2064 if (c->flags & CHAN_EOF_RCVD) {
2065 if (datafellows & SSH_BUG_EXTEOF)
2066 debug("channel %d: accepting ext data after eof", id);
2067 else
2068 packet_disconnect("Received extended_data after EOF "
2069 "on channel %d.", id);
2070 }
2071 tcode = packet_get_int();
2072 if (c->efd == -1 ||
2073 c->extended_usage != CHAN_EXTENDED_WRITE ||
2074 tcode != SSH2_EXTENDED_DATA_STDERR) {
2075 logit("channel %d: bad ext data", c->self);
2076 return;
2077 }
2078 data = packet_get_string(&data_len);
2079 packet_check_eom();
2080 if (data_len > c->local_window) {
2081 logit("channel %d: rcvd too much extended_data %d, win %d",
2082 c->self, data_len, c->local_window);
2083 xfree(data);
2084 return;
2085 }
2086 debug2("channel %d: rcvd ext data %d", c->self, data_len);
2087 c->local_window -= data_len;
2088 buffer_append(&c->extended, data, data_len);
2089 xfree(data);
2090 }
2091
2092 /* ARGSUSED */
2093 void
2094 channel_input_ieof(int type, u_int32_t seq, void *ctxt)
2095 {
2096 int id;
2097 Channel *c;
2098
2099 id = packet_get_int();
2100 packet_check_eom();
2101 c = channel_lookup(id);
2102 if (c == NULL)
2103 packet_disconnect("Received ieof for nonexistent channel %d.", id);
2104 chan_rcvd_ieof(c);
2105
2106 /* XXX force input close */
2107 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) {
2108 debug("channel %d: FORCE input drain", c->self);
2109 c->istate = CHAN_INPUT_WAIT_DRAIN;
2110 if (buffer_len(&c->input) == 0)
2111 chan_ibuf_empty(c);
2112 }
2113
2114 }
2115
2116 /* ARGSUSED */
2117 void
2118 channel_input_close(int type, u_int32_t seq, void *ctxt)
2119 {
2120 int id;
2121 Channel *c;
2122
2123 id = packet_get_int();
2124 packet_check_eom();
2125 c = channel_lookup(id);
2126 if (c == NULL)
2127 packet_disconnect("Received close for nonexistent channel %d.", id);
2128
2129 /*
2130 * Send a confirmation that we have closed the channel and no more
2131 * data is coming for it.
2132 */
2133 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
2134 packet_put_int(c->remote_id);
2135 packet_send();
2136
2137 /*
2138 * If the channel is in closed state, we have sent a close request,
2139 * and the other side will eventually respond with a confirmation.
2140 * Thus, we cannot free the channel here, because then there would be
2141 * no-one to receive the confirmation. The channel gets freed when
2142 * the confirmation arrives.
2143 */
2144 if (c->type != SSH_CHANNEL_CLOSED) {
2145 /*
2146 * Not a closed channel - mark it as draining, which will
2147 * cause it to be freed later.
2148 */
2149 buffer_clear(&c->input);
2150 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
2151 }
2152 }
2153
2154 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
2155 /* ARGSUSED */
2156 void
2157 channel_input_oclose(int type, u_int32_t seq, void *ctxt)
2158 {
2159 int id = packet_get_int();
2160 Channel *c = channel_lookup(id);
2161
2162 packet_check_eom();
2163 if (c == NULL)
2164 packet_disconnect("Received oclose for nonexistent channel %d.", id);
2165 chan_rcvd_oclose(c);
2166 }
2167
2168 /* ARGSUSED */
2169 void
2170 channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt)
2171 {
2172 int id = packet_get_int();
2173 Channel *c = channel_lookup(id);
2174
2175 packet_check_eom();
2176 if (c == NULL)
2177 packet_disconnect("Received close confirmation for "
2178 "out-of-range channel %d.", id);
2179 if (c->type != SSH_CHANNEL_CLOSED)
2180 packet_disconnect("Received close confirmation for "
2181 "non-closed channel %d (type %d).", id, c->type);
2182 channel_free(c);
2183 }
2184
2185 /* ARGSUSED */
2186 void
2187 channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt)
2188 {
2189 int id, remote_id;
2190 Channel *c;
2191
2192 id = packet_get_int();
2193 c = channel_lookup(id);
2194
2195 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2196 packet_disconnect("Received open confirmation for "
2197 "non-opening channel %d.", id);
2198 remote_id = packet_get_int();
2199 /* Record the remote channel number and mark that the channel is now open. */
2200 c->remote_id = remote_id;
2201 c->type = SSH_CHANNEL_OPEN;
2202
2203 if (compat20) {
2204 c->remote_window = packet_get_int();
2205 c->remote_maxpacket = packet_get_int();
2206 if (c->confirm) {
2207 debug2("callback start");
2208 c->confirm(c->self, c->confirm_ctx);
2209 debug2("callback done");
2210 }
2211 debug2("channel %d: open confirm rwindow %u rmax %u", c->self,
2212 c->remote_window, c->remote_maxpacket);
2213 }
2214 packet_check_eom();
2215 }
2216
2217 static char *
2218 reason2txt(int reason)
2219 {
2220 switch (reason) {
2221 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
2222 return "administratively prohibited";
2223 case SSH2_OPEN_CONNECT_FAILED:
2224 return "connect failed";
2225 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
2226 return "unknown channel type";
2227 case SSH2_OPEN_RESOURCE_SHORTAGE:
2228 return "resource shortage";
2229 }
2230 return "unknown reason";
2231 }
2232
2233 /* ARGSUSED */
2234 void
2235 channel_input_open_failure(int type, u_int32_t seq, void *ctxt)
2236 {
2237 int id, reason;
2238 char *msg = NULL, *lang = NULL;
2239 Channel *c;
2240
2241 id = packet_get_int();
2242 c = channel_lookup(id);
2243
2244 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2245 packet_disconnect("Received open failure for "
2246 "non-opening channel %d.", id);
2247 if (compat20) {
2248 reason = packet_get_int();
2249 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
2250 msg = packet_get_string(NULL);
2251 lang = packet_get_string(NULL);
2252 }
2253 logit("channel %d: open failed: %s%s%s", id,
2254 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
2255 if (msg != NULL)
2256 xfree(msg);
2257 if (lang != NULL)
2258 xfree(lang);
2259 }
2260 packet_check_eom();
2261 /* Free the channel. This will also close the socket. */
2262 channel_free(c);
2263 }
2264
2265 /* ARGSUSED */
2266 void
2267 channel_input_window_adjust(int type, u_int32_t seq, void *ctxt)
2268 {
2269 Channel *c;
2270 int id;
2271 u_int adjust;
2272
2273 if (!compat20)
2274 return;
2275
2276 /* Get the channel number and verify it. */
2277 id = packet_get_int();
2278 c = channel_lookup(id);
2279
2280 if (c == NULL) {
2281 logit("Received window adjust for non-open channel %d.", id);
2282 return;
2283 }
2284 adjust = packet_get_int();
2285 packet_check_eom();
2286 debug2("channel %d: rcvd adjust %u", id, adjust);
2287 c->remote_window += adjust;
2288 }
2289
2290 /* ARGSUSED */
2291 void
2292 channel_input_port_open(int type, u_int32_t seq, void *ctxt)
2293 {
2294 Channel *c = NULL;
2295 u_short host_port;
2296 char *host, *originator_string;
2297 int remote_id, sock = -1;
2298
2299 remote_id = packet_get_int();
2300 host = packet_get_string(NULL);
2301 host_port = packet_get_int();
2302
2303 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2304 originator_string = packet_get_string(NULL);
2305 } else {
2306 originator_string = xstrdup("unknown (remote did not supply name)");
2307 }
2308 packet_check_eom();
2309 sock = channel_connect_to(host, host_port);
2310 if (sock != -1) {
2311 c = channel_new("connected socket",
2312 SSH_CHANNEL_CONNECTING, sock, sock, -1, 0, 0, 0,
2313 originator_string, 1);
2314 c->remote_id = remote_id;
2315 }
2316 xfree(originator_string);
2317 if (c == NULL) {
2318 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2319 packet_put_int(remote_id);
2320 packet_send();
2321 }
2322 xfree(host);
2323 }
2324
2325
2326 /* -- tcp forwarding */
2327
2328 void
2329 channel_set_af(int af)
2330 {
2331 IPv4or6 = af;
2332 }
2333
2334 static int
2335 channel_setup_fwd_listener(int type, const char *listen_addr, u_short listen_port,
2336 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2337 {
2338 Channel *c;
2339 int sock, r, success = 0, wildcard = 0, is_client;
2340 struct addrinfo hints, *ai, *aitop;
2341 const char *host, *addr;
2342 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2343
2344 host = (type == SSH_CHANNEL_RPORT_LISTENER) ?
2345 listen_addr : host_to_connect;
2346 is_client = (type == SSH_CHANNEL_PORT_LISTENER);
2347
2348 if (host == NULL) {
2349 error("No forward host name.");
2350 return 0;
2351 }
2352 if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) {
2353 error("Forward host name too long.");
2354 return 0;
2355 }
2356
2357 /*
2358 * Determine whether or not a port forward listens to loopback,
2359 * specified address or wildcard. On the client, a specified bind
2360 * address will always override gateway_ports. On the server, a
2361 * gateway_ports of 1 (``yes'') will override the client's
2362 * specification and force a wildcard bind, whereas a value of 2
2363 * (``clientspecified'') will bind to whatever address the client
2364 * asked for.
2365 *
2366 * Special-case listen_addrs are:
2367 *
2368 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR
2369 * "" (empty string), "*" -> wildcard v4/v6
2370 * "localhost" -> loopback v4/v6
2371 */
2372 addr = NULL;
2373 if (listen_addr == NULL) {
2374 /* No address specified: default to gateway_ports setting */
2375 if (gateway_ports)
2376 wildcard = 1;
2377 } else if (gateway_ports || is_client) {
2378 if (((datafellows & SSH_OLD_FORWARD_ADDR) &&
2379 strcmp(listen_addr, "0.0.0.0") == 0) ||
2380 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 ||
2381 (!is_client && gateway_ports == 1))
2382 wildcard = 1;
2383 else if (strcmp(listen_addr, "localhost") != 0)
2384 addr = listen_addr;
2385 }
2386
2387 debug3("channel_setup_fwd_listener: type %d wildcard %d addr %s",
2388 type, wildcard, (addr == NULL) ? "NULL" : addr);
2389
2390 /*
2391 * getaddrinfo returns a loopback address if the hostname is
2392 * set to NULL and hints.ai_flags is not AI_PASSIVE
2393 */
2394 memset(&hints, 0, sizeof(hints));
2395 hints.ai_family = IPv4or6;
2396 hints.ai_flags = wildcard ? AI_PASSIVE : 0;
2397 hints.ai_socktype = SOCK_STREAM;
2398 snprintf(strport, sizeof strport, "%d", listen_port);
2399 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) {
2400 if (addr == NULL) {
2401 /* This really shouldn't happen */
2402 packet_disconnect("getaddrinfo: fatal error: %s",
2403 gai_strerror(r));
2404 } else {
2405 error("channel_setup_fwd_listener: "
2406 "getaddrinfo(%.64s): %s", addr, gai_strerror(r));
2407 }
2408 return 0;
2409 }
2410
2411 for (ai = aitop; ai; ai = ai->ai_next) {
2412 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2413 continue;
2414 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2415 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2416 error("channel_setup_fwd_listener: getnameinfo failed");
2417 continue;
2418 }
2419 /* Create a port to listen for the host. */
2420 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2421 if (sock < 0) {
2422 /* this is no error since kernel may not support ipv6 */
2423 verbose("socket: %.100s", strerror(errno));
2424 continue;
2425 }
2426
2427 channel_set_reuseaddr(sock);
2428
2429 debug("Local forwarding listening on %s port %s.", ntop, strport);
2430
2431 /* Bind the socket to the address. */
2432 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2433 /* address can be in use ipv6 address is already bound */
2434 if (!ai->ai_next)
2435 error("bind: %.100s", strerror(errno));
2436 else
2437 verbose("bind: %.100s", strerror(errno));
2438
2439 close(sock);
2440 continue;
2441 }
2442 /* Start listening for connections on the socket. */
2443 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2444 error("listen: %.100s", strerror(errno));
2445 close(sock);
2446 continue;
2447 }
2448 /* Allocate a channel number for the socket. */
2449 c = channel_new("port listener", type, sock, sock, -1,
2450 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2451 0, "port listener", 1);
2452 strlcpy(c->path, host, sizeof(c->path));
2453 c->host_port = port_to_connect;
2454 c->listening_port = listen_port;
2455 success = 1;
2456 }
2457 if (success == 0)
2458 error("channel_setup_fwd_listener: cannot listen to port: %d",
2459 listen_port);
2460 freeaddrinfo(aitop);
2461 return success;
2462 }
2463
2464 int
2465 channel_cancel_rport_listener(const char *host, u_short port)
2466 {
2467 u_int i;
2468 int found = 0;
2469
2470 for (i = 0; i < channels_alloc; i++) {
2471 Channel *c = channels[i];
2472
2473 if (c != NULL && c->type == SSH_CHANNEL_RPORT_LISTENER &&
2474 strncmp(c->path, host, sizeof(c->path)) == 0 &&
2475 c->listening_port == port) {
2476 debug2("%s: close channel %d", __func__, i);
2477 channel_free(c);
2478 found = 1;
2479 }
2480 }
2481
2482 return (found);
2483 }
2484
2485 /* protocol local port fwd, used by ssh (and sshd in v1) */
2486 int
2487 channel_setup_local_fwd_listener(const char *listen_host, u_short listen_port,
2488 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2489 {
2490 return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER,
2491 listen_host, listen_port, host_to_connect, port_to_connect,
2492 gateway_ports);
2493 }
2494
2495 /* protocol v2 remote port fwd, used by sshd */
2496 int
2497 channel_setup_remote_fwd_listener(const char *listen_address,
2498 u_short listen_port, int gateway_ports)
2499 {
2500 return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER,
2501 listen_address, listen_port, NULL, 0, gateway_ports);
2502 }
2503
2504 /*
2505 * Initiate forwarding of connections to port "port" on remote host through
2506 * the secure channel to host:port from local side.
2507 */
2508
2509 int
2510 channel_request_remote_forwarding(const char *listen_host, u_short listen_port,
2511 const char *host_to_connect, u_short port_to_connect)
2512 {
2513 int type, success = 0;
2514
2515 /* Record locally that connection to this host/port is permitted. */
2516 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2517 fatal("channel_request_remote_forwarding: too many forwards");
2518
2519 /* Send the forward request to the remote side. */
2520 if (compat20) {
2521 const char *address_to_bind;
2522 if (listen_host == NULL)
2523 address_to_bind = "localhost";
2524 else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0)
2525 address_to_bind = "";
2526 else
2527 address_to_bind = listen_host;
2528
2529 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2530 packet_put_cstring("tcpip-forward");
2531 packet_put_char(1); /* boolean: want reply */
2532 packet_put_cstring(address_to_bind);
2533 packet_put_int(listen_port);
2534 packet_send();
2535 packet_write_wait();
2536 /* Assume that server accepts the request */
2537 success = 1;
2538 } else {
2539 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2540 packet_put_int(listen_port);
2541 packet_put_cstring(host_to_connect);
2542 packet_put_int(port_to_connect);
2543 packet_send();
2544 packet_write_wait();
2545
2546 /* Wait for response from the remote side. */
2547 type = packet_read();
2548 switch (type) {
2549 case SSH_SMSG_SUCCESS:
2550 success = 1;
2551 break;
2552 case SSH_SMSG_FAILURE:
2553 break;
2554 default:
2555 /* Unknown packet */
2556 packet_disconnect("Protocol error for port forward request:"
2557 "received packet type %d.", type);
2558 }
2559 }
2560 if (success) {
2561 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2562 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2563 permitted_opens[num_permitted_opens].listen_port = listen_port;
2564 num_permitted_opens++;
2565 }
2566 return (success ? 0 : -1);
2567 }
2568
2569 /*
2570 * Request cancellation of remote forwarding of connection host:port from
2571 * local side.
2572 */
2573 void
2574 channel_request_rforward_cancel(const char *host, u_short port)
2575 {
2576 int i;
2577
2578 if (!compat20)
2579 return;
2580
2581 for (i = 0; i < num_permitted_opens; i++) {
2582 if (permitted_opens[i].host_to_connect != NULL &&
2583 permitted_opens[i].listen_port == port)
2584 break;
2585 }
2586 if (i >= num_permitted_opens) {
2587 debug("%s: requested forward not found", __func__);
2588 return;
2589 }
2590 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2591 packet_put_cstring("cancel-tcpip-forward");
2592 packet_put_char(0);
2593 packet_put_cstring(host == NULL ? "" : host);
2594 packet_put_int(port);
2595 packet_send();
2596
2597 permitted_opens[i].listen_port = 0;
2598 permitted_opens[i].port_to_connect = 0;
2599 xfree(permitted_opens[i].host_to_connect);
2600 permitted_opens[i].host_to_connect = NULL;
2601 }
2602
2603 /*
2604 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
2605 * listening for the port, and sends back a success reply (or disconnect
2606 * message if there was an error).
2607 */
2608 int
2609 channel_input_port_forward_request(int is_root, int gateway_ports)
2610 {
2611 u_short port, host_port;
2612 int success = 0;
2613 char *hostname;
2614
2615 /* Get arguments from the packet. */
2616 port = packet_get_int();
2617 hostname = packet_get_string(NULL);
2618 host_port = packet_get_int();
2619
2620 #ifndef HAVE_CYGWIN
2621 /*
2622 * Check that an unprivileged user is not trying to forward a
2623 * privileged port.
2624 */
2625 if (port < IPPORT_RESERVED && !is_root)
2626 packet_disconnect(
2627 "Requested forwarding of port %d but user is not root.",
2628 port);
2629 if (host_port == 0)
2630 packet_disconnect("Dynamic forwarding denied.");
2631 #endif
2632
2633 /* Initiate forwarding */
2634 success = channel_setup_local_fwd_listener(NULL, port, hostname,
2635 host_port, gateway_ports);
2636
2637 /* Free the argument string. */
2638 xfree(hostname);
2639
2640 return (success ? 0 : -1);
2641 }
2642
2643 /*
2644 * Permits opening to any host/port if permitted_opens[] is empty. This is
2645 * usually called by the server, because the user could connect to any port
2646 * anyway, and the server has no way to know but to trust the client anyway.
2647 */
2648 void
2649 channel_permit_all_opens(void)
2650 {
2651 if (num_permitted_opens == 0)
2652 all_opens_permitted = 1;
2653 }
2654
2655 void
2656 channel_add_permitted_opens(char *host, int port)
2657 {
2658 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2659 fatal("channel_add_permitted_opens: too many forwards");
2660 debug("allow port forwarding to host %s port %d", host, port);
2661
2662 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
2663 permitted_opens[num_permitted_opens].port_to_connect = port;
2664 num_permitted_opens++;
2665
2666 all_opens_permitted = 0;
2667 }
2668
2669 int
2670 channel_add_adm_permitted_opens(char *host, int port)
2671 {
2672 if (num_adm_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2673 fatal("channel_add_adm_permitted_opens: too many forwards");
2674 debug("config allows port forwarding to host %s port %d", host, port);
2675
2676 permitted_adm_opens[num_adm_permitted_opens].host_to_connect
2677 = xstrdup(host);
2678 permitted_adm_opens[num_adm_permitted_opens].port_to_connect = port;
2679 return ++num_adm_permitted_opens;
2680 }
2681
2682 void
2683 channel_clear_permitted_opens(void)
2684 {
2685 int i;
2686
2687 for (i = 0; i < num_permitted_opens; i++)
2688 if (permitted_opens[i].host_to_connect != NULL)
2689 xfree(permitted_opens[i].host_to_connect);
2690 num_permitted_opens = 0;
2691 }
2692
2693 void
2694 channel_clear_adm_permitted_opens(void)
2695 {
2696 int i;
2697
2698 for (i = 0; i < num_adm_permitted_opens; i++)
2699 if (permitted_adm_opens[i].host_to_connect != NULL)
2700 xfree(permitted_adm_opens[i].host_to_connect);
2701 num_adm_permitted_opens = 0;
2702 }
2703
2704 /* return socket to remote host, port */
2705 static int
2706 connect_to(const char *host, u_short port)
2707 {
2708 struct addrinfo hints, *ai, *aitop;
2709 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2710 int gaierr;
2711 int sock = -1;
2712
2713 memset(&hints, 0, sizeof(hints));
2714 hints.ai_family = IPv4or6;
2715 hints.ai_socktype = SOCK_STREAM;
2716 snprintf(strport, sizeof strport, "%d", port);
2717 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
2718 error("connect_to %.100s: unknown host (%s)", host,
2719 gai_strerror(gaierr));
2720 return -1;
2721 }
2722 for (ai = aitop; ai; ai = ai->ai_next) {
2723 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2724 continue;
2725 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2726 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2727 error("connect_to: getnameinfo failed");
2728 continue;
2729 }
2730 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2731 if (sock < 0) {
2732 if (ai->ai_next == NULL)
2733 error("socket: %.100s", strerror(errno));
2734 else
2735 verbose("socket: %.100s", strerror(errno));
2736 continue;
2737 }
2738 if (set_nonblock(sock) == -1)
2739 fatal("%s: set_nonblock(%d)", __func__, sock);
2740 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 &&
2741 errno != EINPROGRESS) {
2742 error("connect_to %.100s port %s: %.100s", ntop, strport,
2743 strerror(errno));
2744 close(sock);
2745 continue; /* fail -- try next */
2746 }
2747 break; /* success */
2748
2749 }
2750 freeaddrinfo(aitop);
2751 if (!ai) {
2752 error("connect_to %.100s port %d: failed.", host, port);
2753 return -1;
2754 }
2755 /* success */
2756 set_nodelay(sock);
2757 return sock;
2758 }
2759
2760 int
2761 channel_connect_by_listen_address(u_short listen_port)
2762 {
2763 int i;
2764
2765 for (i = 0; i < num_permitted_opens; i++)
2766 if (permitted_opens[i].host_to_connect != NULL &&
2767 permitted_opens[i].listen_port == listen_port)
2768 return connect_to(
2769 permitted_opens[i].host_to_connect,
2770 permitted_opens[i].port_to_connect);
2771 error("WARNING: Server requests forwarding for unknown listen_port %d",
2772 listen_port);
2773 return -1;
2774 }
2775
2776 /* Check if connecting to that port is permitted and connect. */
2777 int
2778 channel_connect_to(const char *host, u_short port)
2779 {
2780 int i, permit, permit_adm = 1;
2781
2782 permit = all_opens_permitted;
2783 if (!permit) {
2784 for (i = 0; i < num_permitted_opens; i++)
2785 if (permitted_opens[i].host_to_connect != NULL &&
2786 permitted_opens[i].port_to_connect == port &&
2787 strcmp(permitted_opens[i].host_to_connect, host) == 0)
2788 permit = 1;
2789 }
2790
2791 if (num_adm_permitted_opens > 0) {
2792 permit_adm = 0;
2793 for (i = 0; i < num_adm_permitted_opens; i++)
2794 if (permitted_adm_opens[i].host_to_connect != NULL &&
2795 permitted_adm_opens[i].port_to_connect == port &&
2796 strcmp(permitted_adm_opens[i].host_to_connect, host)
2797 == 0)
2798 permit_adm = 1;
2799 }
2800
2801 if (!permit || !permit_adm) {
2802 logit("Received request to connect to host %.100s port %d, "
2803 "but the request was denied.", host, port);
2804 return -1;
2805 }
2806 return connect_to(host, port);
2807 }
2808
2809 void
2810 channel_send_window_changes(void)
2811 {
2812 u_int i;
2813 struct winsize ws;
2814
2815 for (i = 0; i < channels_alloc; i++) {
2816 if (channels[i] == NULL || !channels[i]->client_tty ||
2817 channels[i]->type != SSH_CHANNEL_OPEN)
2818 continue;
2819 if (ioctl(channels[i]->rfd, TIOCGWINSZ, &ws) < 0)
2820 continue;
2821 channel_request_start(i, "window-change", 0);
2822 packet_put_int((u_int)ws.ws_col);
2823 packet_put_int((u_int)ws.ws_row);
2824 packet_put_int((u_int)ws.ws_xpixel);
2825 packet_put_int((u_int)ws.ws_ypixel);
2826 packet_send();
2827 }
2828 }
2829
2830 /* -- X11 forwarding */
2831
2832 /*
2833 * Creates an internet domain socket for listening for X11 connections.
2834 * Returns 0 and a suitable display number for the DISPLAY variable
2835 * stored in display_numberp , or -1 if an error occurs.
2836 */
2837 int
2838 x11_create_display_inet(int x11_display_offset, int x11_use_localhost,
2839 int single_connection, u_int *display_numberp, int **chanids)
2840 {
2841 Channel *nc = NULL;
2842 int display_number, sock;
2843 u_short port;
2844 struct addrinfo hints, *ai, *aitop;
2845 char strport[NI_MAXSERV];
2846 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
2847
2848 if (chanids == NULL)
2849 return -1;
2850
2851 for (display_number = x11_display_offset;
2852 display_number < MAX_DISPLAYS;
2853 display_number++) {
2854 port = 6000 + display_number;
2855 memset(&hints, 0, sizeof(hints));
2856 hints.ai_family = IPv4or6;
2857 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE;
2858 hints.ai_socktype = SOCK_STREAM;
2859 snprintf(strport, sizeof strport, "%d", port);
2860 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
2861 error("getaddrinfo: %.100s", gai_strerror(gaierr));
2862 return -1;
2863 }
2864 for (ai = aitop; ai; ai = ai->ai_next) {
2865 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2866 continue;
2867 sock = socket(ai->ai_family, ai->ai_socktype,
2868 ai->ai_protocol);
2869 if (sock < 0) {
2870 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
2871 error("socket: %.100s", strerror(errno));
2872 freeaddrinfo(aitop);
2873 return -1;
2874 } else {
2875 debug("x11_create_display_inet: Socket family %d not supported",
2876 ai->ai_family);
2877 continue;
2878 }
2879 }
2880 #ifdef IPV6_V6ONLY
2881 if (ai->ai_family == AF_INET6) {
2882 int on = 1;
2883 if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) < 0)
2884 error("setsockopt IPV6_V6ONLY: %.100s", strerror(errno));
2885 }
2886 #endif
2887 channel_set_reuseaddr(sock);
2888 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2889 debug2("bind port %d: %.100s", port, strerror(errno));
2890 close(sock);
2891
2892 if (ai->ai_next)
2893 continue;
2894
2895 for (n = 0; n < num_socks; n++) {
2896 close(socks[n]);
2897 }
2898 num_socks = 0;
2899 break;
2900 }
2901 socks[num_socks++] = sock;
2902 #ifndef DONT_TRY_OTHER_AF
2903 if (num_socks == NUM_SOCKS)
2904 break;
2905 #else
2906 if (x11_use_localhost) {
2907 if (num_socks == NUM_SOCKS)
2908 break;
2909 } else {
2910 break;
2911 }
2912 #endif
2913 }
2914 freeaddrinfo(aitop);
2915 if (num_socks > 0)
2916 break;
2917 }
2918 if (display_number >= MAX_DISPLAYS) {
2919 error("Failed to allocate internet-domain X11 display socket.");
2920 return -1;
2921 }
2922 /* Start listening for connections on the socket. */
2923 for (n = 0; n < num_socks; n++) {
2924 sock = socks[n];
2925 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2926 error("listen: %.100s", strerror(errno));
2927 close(sock);
2928 return -1;
2929 }
2930 }
2931
2932 /* Allocate a channel for each socket. */
2933 *chanids = xcalloc(num_socks + 1, sizeof(**chanids));
2934 for (n = 0; n < num_socks; n++) {
2935 sock = socks[n];
2936 nc = channel_new("x11 listener",
2937 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
2938 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2939 0, "X11 inet listener", 1);
2940 nc->single_connection = single_connection;
2941 (*chanids)[n] = nc->self;
2942 }
2943 (*chanids)[n] = -1;
2944
2945 /* Return the display number for the DISPLAY environment variable. */
2946 *display_numberp = display_number;
2947 return (0);
2948 }
2949
2950 static int
2951 connect_local_xsocket(u_int dnr)
2952 {
2953 int sock;
2954 struct sockaddr_un addr;
2955
2956 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2957 if (sock < 0)
2958 error("socket: %.100s", strerror(errno));
2959 memset(&addr, 0, sizeof(addr));
2960 addr.sun_family = AF_UNIX;
2961 snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr);
2962 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0)
2963 return sock;
2964 close(sock);
2965 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
2966 return -1;
2967 }
2968
2969 int
2970 x11_connect_display(void)
2971 {
2972 u_int display_number;
2973 const char *display;
2974 char buf[1024], *cp;
2975 struct addrinfo hints, *ai, *aitop;
2976 char strport[NI_MAXSERV];
2977 int gaierr, sock = 0;
2978
2979 /* Try to open a socket for the local X server. */
2980 display = getenv("DISPLAY");
2981 if (!display) {
2982 error("DISPLAY not set.");
2983 return -1;
2984 }
2985 /*
2986 * Now we decode the value of the DISPLAY variable and make a
2987 * connection to the real X server.
2988 */
2989
2990 /*
2991 * Check if it is a unix domain socket. Unix domain displays are in
2992 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
2993 */
2994 if (strncmp(display, "unix:", 5) == 0 ||
2995 display[0] == ':') {
2996 /* Connect to the unix domain socket. */
2997 if (sscanf(strrchr(display, ':') + 1, "%u", &display_number) != 1) {
2998 error("Could not parse display number from DISPLAY: %.100s",
2999 display);
3000 return -1;
3001 }
3002 /* Create a socket. */
3003 sock = connect_local_xsocket(display_number);
3004 if (sock < 0)
3005 return -1;
3006
3007 /* OK, we now have a connection to the display. */
3008 return sock;
3009 }
3010 /*
3011 * Connect to an inet socket. The DISPLAY value is supposedly
3012 * hostname:d[.s], where hostname may also be numeric IP address.
3013 */
3014 strlcpy(buf, display, sizeof(buf));
3015 cp = strchr(buf, ':');
3016 if (!cp) {
3017 error("Could not find ':' in DISPLAY: %.100s", display);
3018 return -1;
3019 }
3020 *cp = 0;
3021 /* buf now contains the host name. But first we parse the display number. */
3022 if (sscanf(cp + 1, "%u", &display_number) != 1) {
3023 error("Could not parse display number from DISPLAY: %.100s",
3024 display);
3025 return -1;
3026 }
3027
3028 /* Look up the host address */
3029 memset(&hints, 0, sizeof(hints));
3030 hints.ai_family = IPv4or6;
3031 hints.ai_socktype = SOCK_STREAM;
3032 snprintf(strport, sizeof strport, "%u", 6000 + display_number);
3033 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
3034 error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr));
3035 return -1;
3036 }
3037 for (ai = aitop; ai; ai = ai->ai_next) {
3038 /* Create a socket. */
3039 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
3040 if (sock < 0) {
3041 debug2("socket: %.100s", strerror(errno));
3042 continue;
3043 }
3044 /* Connect it to the display. */
3045 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
3046 debug2("connect %.100s port %u: %.100s", buf,
3047 6000 + display_number, strerror(errno));
3048 close(sock);
3049 continue;
3050 }
3051 /* Success */
3052 break;
3053 }
3054 freeaddrinfo(aitop);
3055 if (!ai) {
3056 error("connect %.100s port %u: %.100s", buf, 6000 + display_number,
3057 strerror(errno));
3058 return -1;
3059 }
3060 set_nodelay(sock);
3061 return sock;
3062 }
3063
3064 /*
3065 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
3066 * the remote channel number. We should do whatever we want, and respond
3067 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
3068 */
3069
3070 /* ARGSUSED */
3071 void
3072 x11_input_open(int type, u_int32_t seq, void *ctxt)
3073 {
3074 Channel *c = NULL;
3075 int remote_id, sock = 0;
3076 char *remote_host;
3077
3078 debug("Received X11 open request.");
3079
3080 remote_id = packet_get_int();
3081
3082 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
3083 remote_host = packet_get_string(NULL);
3084 } else {
3085 remote_host = xstrdup("unknown (remote did not supply name)");
3086 }
3087 packet_check_eom();
3088
3089 /* Obtain a connection to the real X display. */
3090 sock = x11_connect_display();
3091 if (sock != -1) {
3092 /* Allocate a channel for this connection. */
3093 c = channel_new("connected x11 socket",
3094 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
3095 remote_host, 1);
3096 c->remote_id = remote_id;
3097 c->force_drain = 1;
3098 }
3099 xfree(remote_host);
3100 if (c == NULL) {
3101 /* Send refusal to the remote host. */
3102 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3103 packet_put_int(remote_id);
3104 } else {
3105 /* Send a confirmation to the remote host. */
3106 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
3107 packet_put_int(remote_id);
3108 packet_put_int(c->self);
3109 }
3110 packet_send();
3111 }
3112
3113 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
3114 /* ARGSUSED */
3115 void
3116 deny_input_open(int type, u_int32_t seq, void *ctxt)
3117 {
3118 int rchan = packet_get_int();
3119
3120 switch (type) {
3121 case SSH_SMSG_AGENT_OPEN:
3122 error("Warning: ssh server tried agent forwarding.");
3123 break;
3124 case SSH_SMSG_X11_OPEN:
3125 error("Warning: ssh server tried X11 forwarding.");
3126 break;
3127 default:
3128 error("deny_input_open: type %d", type);
3129 break;
3130 }
3131 error("Warning: this is probably a break-in attempt by a malicious server.");
3132 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3133 packet_put_int(rchan);
3134 packet_send();
3135 }
3136
3137 /*
3138 * Requests forwarding of X11 connections, generates fake authentication
3139 * data, and enables authentication spoofing.
3140 * This should be called in the client only.
3141 */
3142 void
3143 x11_request_forwarding_with_spoofing(int client_session_id, const char *disp,
3144 const char *proto, const char *data)
3145 {
3146 u_int data_len = (u_int) strlen(data) / 2;
3147 u_int i, value;
3148 char *new_data;
3149 int screen_number;
3150 const char *cp;
3151 u_int32_t rnd = 0;
3152
3153 if (x11_saved_display == NULL)
3154 x11_saved_display = xstrdup(disp);
3155 else if (strcmp(disp, x11_saved_display) != 0) {
3156 error("x11_request_forwarding_with_spoofing: different "
3157 "$DISPLAY already forwarded");
3158 return;
3159 }
3160
3161 cp = disp;
3162 if (disp)
3163 cp = strchr(disp, ':');
3164 if (cp)
3165 cp = strchr(cp, '.');
3166 if (cp)
3167 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL);
3168 else
3169 screen_number = 0;
3170
3171 if (x11_saved_proto == NULL) {
3172 /* Save protocol name. */
3173 x11_saved_proto = xstrdup(proto);
3174 /*
3175 * Extract real authentication data and generate fake data
3176 * of the same length.
3177 */
3178 x11_saved_data = xmalloc(data_len);
3179 x11_fake_data = xmalloc(data_len);
3180 for (i = 0; i < data_len; i++) {
3181 if (sscanf(data + 2 * i, "%2x", &value) != 1)
3182 fatal("x11_request_forwarding: bad "
3183 "authentication data: %.100s", data);
3184 if (i % 4 == 0)
3185 rnd = arc4random();
3186 x11_saved_data[i] = value;
3187 x11_fake_data[i] = rnd & 0xff;
3188 rnd >>= 8;
3189 }
3190 x11_saved_data_len = data_len;
3191 x11_fake_data_len = data_len;
3192 }
3193
3194 /* Convert the fake data into hex. */
3195 new_data = tohex(x11_fake_data, data_len);
3196
3197 /* Send the request packet. */
3198 if (compat20) {
3199 channel_request_start(client_session_id, "x11-req", 0);
3200 packet_put_char(0); /* XXX bool single connection */
3201 } else {
3202 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
3203 }
3204 packet_put_cstring(proto);
3205 packet_put_cstring(new_data);
3206 packet_put_int(screen_number);
3207 packet_send();
3208 packet_write_wait();
3209 xfree(new_data);
3210 }
3211
3212
3213 /* -- agent forwarding */
3214
3215 /* Sends a message to the server to request authentication fd forwarding. */
3216
3217 void
3218 auth_request_forwarding(void)
3219 {
3220 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
3221 packet_send();
3222 packet_write_wait();
3223 }
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