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Fix references.
[dragonfly.git] / crypto / openssh-4 / channels.c
blob2006353d40e769e62d885f9b67973e6942eb4645
1 /* $OpenBSD: channels.c,v 1.270 2007/06/25 08:20:03 dtucker Exp $ */
2 /*
3 * Author: Tatu Ylonen <ylo@cs.hut.fi>
4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5 * All rights reserved
6 * This file contains functions for generic socket connection forwarding.
7 * There is also code for initiating connection forwarding for X11 connections,
8 * arbitrary tcp/ip connections, and the authentication agent connection.
9 *
10 * As far as I am concerned, the code I have written for this software
11 * can be used freely for any purpose. Any derived versions of this
12 * software must be clearly marked as such, and if the derived work is
13 * incompatible with the protocol description in the RFC file, it must be
14 * called by a name other than "ssh" or "Secure Shell".
15 *
16 * SSH2 support added by Markus Friedl.
17 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved.
18 * Copyright (c) 1999 Dug Song. All rights reserved.
19 * Copyright (c) 1999 Theo de Raadt. All rights reserved.
20 *
21 * Redistribution and use in source and binary forms, with or without
22 * modification, are permitted provided that the following conditions
23 * are met:
24 * 1. Redistributions of source code must retain the above copyright
25 * notice, this list of conditions and the following disclaimer.
26 * 2. Redistributions in binary form must reproduce the above copyright
27 * notice, this list of conditions and the following disclaimer in the
28 * documentation and/or other materials provided with the distribution.
29 *
30 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
31 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
32 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
33 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
34 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
35 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
36 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
37 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
38 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
39 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
40 */
41
42 #include "includes.h"
43
44 #include <sys/types.h>
45 #include <sys/ioctl.h>
46 #include <sys/un.h>
47 #include <sys/socket.h>
48 #ifdef HAVE_SYS_TIME_H
49 # include <sys/time.h>
50 #endif
51
52 #include <netinet/in.h>
53 #include <arpa/inet.h>
54
55 #include <errno.h>
56 #include <netdb.h>
57 #include <stdio.h>
58 #include <stdlib.h>
59 #include <string.h>
60 #include <termios.h>
61 #include <unistd.h>
62 #include <stdarg.h>
63
64 #include "xmalloc.h"
65 #include "ssh.h"
66 #include "ssh1.h"
67 #include "ssh2.h"
68 #include "packet.h"
69 #include "log.h"
70 #include "misc.h"
71 #include "buffer.h"
72 #include "channels.h"
73 #include "compat.h"
74 #include "canohost.h"
75 #include "key.h"
76 #include "authfd.h"
77 #include "pathnames.h"
78
79 /* -- channel core */
80
81 /*
82 * Pointer to an array containing all allocated channels. The array is
83 * dynamically extended as needed.
84 */
85 static Channel **channels = NULL;
86
87 /*
88 * Size of the channel array. All slots of the array must always be
89 * initialized (at least the type field); unused slots set to NULL
90 */
91 static u_int channels_alloc = 0;
92
93 /*
94 * Maximum file descriptor value used in any of the channels. This is
95 * updated in channel_new.
96 */
97 static int channel_max_fd = 0;
98
99
100 /* -- tcp forwarding */
101
102 /*
103 * Data structure for storing which hosts are permitted for forward requests.
104 * The local sides of any remote forwards are stored in this array to prevent
105 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local
106 * network (which might be behind a firewall).
107 */
108 typedef struct {
109 char *host_to_connect; /* Connect to 'host'. */
110 u_short port_to_connect; /* Connect to 'port'. */
111 u_short listen_port; /* Remote side should listen port number. */
112 } ForwardPermission;
113
114 /* List of all permitted host/port pairs to connect by the user. */
115 static ForwardPermission permitted_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
116
117 /* List of all permitted host/port pairs to connect by the admin. */
118 static ForwardPermission permitted_adm_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
119
120 /* Number of permitted host/port pairs in the array permitted by the user. */
121 static int num_permitted_opens = 0;
122
123 /* Number of permitted host/port pair in the array permitted by the admin. */
124 static int num_adm_permitted_opens = 0;
125
126 /*
127 * If this is true, all opens are permitted. This is the case on the server
128 * on which we have to trust the client anyway, and the user could do
129 * anything after logging in anyway.
130 */
131 static int all_opens_permitted = 0;
132
133
134 /* -- X11 forwarding */
135
136 /* Maximum number of fake X11 displays to try. */
137 #define MAX_DISPLAYS 1000
138
139 /* Saved X11 local (client) display. */
140 static char *x11_saved_display = NULL;
141
142 /* Saved X11 authentication protocol name. */
143 static char *x11_saved_proto = NULL;
144
145 /* Saved X11 authentication data. This is the real data. */
146 static char *x11_saved_data = NULL;
147 static u_int x11_saved_data_len = 0;
148
149 /*
150 * Fake X11 authentication data. This is what the server will be sending us;
151 * we should replace any occurrences of this by the real data.
152 */
153 static u_char *x11_fake_data = NULL;
154 static u_int x11_fake_data_len;
155
156
157 /* -- agent forwarding */
158
159 #define NUM_SOCKS 10
160
161 /* AF_UNSPEC or AF_INET or AF_INET6 */
162 static int IPv4or6 = AF_UNSPEC;
163
164 /* helper */
165 static void port_open_helper(Channel *c, char *rtype);
166
167 /* -- channel core */
168
169 Channel *
170 channel_by_id(int id)
171 {
172 Channel *c;
173
174 if (id < 0 || (u_int)id >= channels_alloc) {
175 logit("channel_by_id: %d: bad id", id);
176 return NULL;
177 }
178 c = channels[id];
179 if (c == NULL) {
180 logit("channel_by_id: %d: bad id: channel free", id);
181 return NULL;
182 }
183 return c;
184 }
185
186 /*
187 * Returns the channel if it is allowed to receive protocol messages.
188 * Private channels, like listening sockets, may not receive messages.
189 */
190 Channel *
191 channel_lookup(int id)
192 {
193 Channel *c;
194
195 if ((c = channel_by_id(id)) == NULL)
196 return (NULL);
197
198 switch (c->type) {
199 case SSH_CHANNEL_X11_OPEN:
200 case SSH_CHANNEL_LARVAL:
201 case SSH_CHANNEL_CONNECTING:
202 case SSH_CHANNEL_DYNAMIC:
203 case SSH_CHANNEL_OPENING:
204 case SSH_CHANNEL_OPEN:
205 case SSH_CHANNEL_INPUT_DRAINING:
206 case SSH_CHANNEL_OUTPUT_DRAINING:
207 return (c);
208 }
209 logit("Non-public channel %d, type %d.", id, c->type);
210 return (NULL);
211 }
212
213 /*
214 * Register filedescriptors for a channel, used when allocating a channel or
215 * when the channel consumer/producer is ready, e.g. shell exec'd
216 */
217 static void
218 channel_register_fds(Channel *c, int rfd, int wfd, int efd,
219 int extusage, int nonblock)
220 {
221 /* Update the maximum file descriptor value. */
222 channel_max_fd = MAX(channel_max_fd, rfd);
223 channel_max_fd = MAX(channel_max_fd, wfd);
224 channel_max_fd = MAX(channel_max_fd, efd);
225
226 /* XXX set close-on-exec -markus */
227
228 c->rfd = rfd;
229 c->wfd = wfd;
230 c->sock = (rfd == wfd) ? rfd : -1;
231 c->ctl_fd = -1; /* XXX: set elsewhere */
232 c->efd = efd;
233 c->extended_usage = extusage;
234
235 /* XXX ugly hack: nonblock is only set by the server */
236 if (nonblock && isatty(c->rfd)) {
237 debug2("channel %d: rfd %d isatty", c->self, c->rfd);
238 c->isatty = 1;
239 if (!isatty(c->wfd)) {
240 error("channel %d: wfd %d is not a tty?",
241 c->self, c->wfd);
242 }
243 } else {
244 c->isatty = 0;
245 }
246 c->wfd_isatty = isatty(c->wfd);
247
248 /* enable nonblocking mode */
249 if (nonblock) {
250 if (rfd != -1)
251 set_nonblock(rfd);
252 if (wfd != -1)
253 set_nonblock(wfd);
254 if (efd != -1)
255 set_nonblock(efd);
256 }
257 }
258
259 /*
260 * Allocate a new channel object and set its type and socket. This will cause
261 * remote_name to be freed.
262 */
263 Channel *
264 channel_new(char *ctype, int type, int rfd, int wfd, int efd,
265 u_int window, u_int maxpack, int extusage, char *remote_name, int nonblock)
266 {
267 int found;
268 u_int i;
269 Channel *c;
270
271 /* Do initial allocation if this is the first call. */
272 if (channels_alloc == 0) {
273 channels_alloc = 10;
274 channels = xcalloc(channels_alloc, sizeof(Channel *));
275 for (i = 0; i < channels_alloc; i++)
276 channels[i] = NULL;
277 }
278 /* Try to find a free slot where to put the new channel. */
279 for (found = -1, i = 0; i < channels_alloc; i++)
280 if (channels[i] == NULL) {
281 /* Found a free slot. */
282 found = (int)i;
283 break;
284 }
285 if (found < 0) {
286 /* There are no free slots. Take last+1 slot and expand the array. */
287 found = channels_alloc;
288 if (channels_alloc > 10000)
289 fatal("channel_new: internal error: channels_alloc %d "
290 "too big.", channels_alloc);
291 channels = xrealloc(channels, channels_alloc + 10,
292 sizeof(Channel *));
293 channels_alloc += 10;
294 debug2("channel: expanding %d", channels_alloc);
295 for (i = found; i < channels_alloc; i++)
296 channels[i] = NULL;
297 }
298 /* Initialize and return new channel. */
299 c = channels[found] = xcalloc(1, sizeof(Channel));
300 buffer_init(&c->input);
301 buffer_init(&c->output);
302 buffer_init(&c->extended);
303 c->ostate = CHAN_OUTPUT_OPEN;
304 c->istate = CHAN_INPUT_OPEN;
305 c->flags = 0;
306 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
307 c->self = found;
308 c->type = type;
309 c->ctype = ctype;
310 c->local_window = window;
311 c->local_window_max = window;
312 c->local_consumed = 0;
313 c->local_maxpacket = maxpack;
314 c->remote_id = -1;
315 c->remote_name = xstrdup(remote_name);
316 c->remote_window = 0;
317 c->remote_maxpacket = 0;
318 c->force_drain = 0;
319 c->single_connection = 0;
320 c->detach_user = NULL;
321 c->detach_close = 0;
322 c->confirm = NULL;
323 c->confirm_ctx = NULL;
324 c->input_filter = NULL;
325 c->output_filter = NULL;
326 debug("channel %d: new [%s]", found, remote_name);
327 return c;
328 }
329
330 static int
331 channel_find_maxfd(void)
332 {
333 u_int i;
334 int max = 0;
335 Channel *c;
336
337 for (i = 0; i < channels_alloc; i++) {
338 c = channels[i];
339 if (c != NULL) {
340 max = MAX(max, c->rfd);
341 max = MAX(max, c->wfd);
342 max = MAX(max, c->efd);
343 }
344 }
345 return max;
346 }
347
348 int
349 channel_close_fd(int *fdp)
350 {
351 int ret = 0, fd = *fdp;
352
353 if (fd != -1) {
354 ret = close(fd);
355 *fdp = -1;
356 if (fd == channel_max_fd)
357 channel_max_fd = channel_find_maxfd();
358 }
359 return ret;
360 }
361
362 /* Close all channel fd/socket. */
363 static void
364 channel_close_fds(Channel *c)
365 {
366 debug3("channel %d: close_fds r %d w %d e %d c %d",
367 c->self, c->rfd, c->wfd, c->efd, c->ctl_fd);
368
369 channel_close_fd(&c->sock);
370 channel_close_fd(&c->ctl_fd);
371 channel_close_fd(&c->rfd);
372 channel_close_fd(&c->wfd);
373 channel_close_fd(&c->efd);
374 }
375
376 /* Free the channel and close its fd/socket. */
377 void
378 channel_free(Channel *c)
379 {
380 char *s;
381 u_int i, n;
382
383 for (n = 0, i = 0; i < channels_alloc; i++)
384 if (channels[i])
385 n++;
386 debug("channel %d: free: %s, nchannels %u", c->self,
387 c->remote_name ? c->remote_name : "???", n);
388
389 s = channel_open_message();
390 debug3("channel %d: status: %s", c->self, s);
391 xfree(s);
392
393 if (c->sock != -1)
394 shutdown(c->sock, SHUT_RDWR);
395 if (c->ctl_fd != -1)
396 shutdown(c->ctl_fd, SHUT_RDWR);
397 channel_close_fds(c);
398 buffer_free(&c->input);
399 buffer_free(&c->output);
400 buffer_free(&c->extended);
401 if (c->remote_name) {
402 xfree(c->remote_name);
403 c->remote_name = NULL;
404 }
405 channels[c->self] = NULL;
406 xfree(c);
407 }
408
409 void
410 channel_free_all(void)
411 {
412 u_int i;
413
414 for (i = 0; i < channels_alloc; i++)
415 if (channels[i] != NULL)
416 channel_free(channels[i]);
417 }
418
419 /*
420 * Closes the sockets/fds of all channels. This is used to close extra file
421 * descriptors after a fork.
422 */
423 void
424 channel_close_all(void)
425 {
426 u_int i;
427
428 for (i = 0; i < channels_alloc; i++)
429 if (channels[i] != NULL)
430 channel_close_fds(channels[i]);
431 }
432
433 /*
434 * Stop listening to channels.
435 */
436 void
437 channel_stop_listening(void)
438 {
439 u_int i;
440 Channel *c;
441
442 for (i = 0; i < channels_alloc; i++) {
443 c = channels[i];
444 if (c != NULL) {
445 switch (c->type) {
446 case SSH_CHANNEL_AUTH_SOCKET:
447 case SSH_CHANNEL_PORT_LISTENER:
448 case SSH_CHANNEL_RPORT_LISTENER:
449 case SSH_CHANNEL_X11_LISTENER:
450 channel_close_fd(&c->sock);
451 channel_free(c);
452 break;
453 }
454 }
455 }
456 }
457
458 /*
459 * Returns true if no channel has too much buffered data, and false if one or
460 * more channel is overfull.
461 */
462 int
463 channel_not_very_much_buffered_data(void)
464 {
465 u_int i;
466 Channel *c;
467
468 for (i = 0; i < channels_alloc; i++) {
469 c = channels[i];
470 if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
471 #if 0
472 if (!compat20 &&
473 buffer_len(&c->input) > packet_get_maxsize()) {
474 debug2("channel %d: big input buffer %d",
475 c->self, buffer_len(&c->input));
476 return 0;
477 }
478 #endif
479 if (buffer_len(&c->output) > packet_get_maxsize()) {
480 debug2("channel %d: big output buffer %u > %u",
481 c->self, buffer_len(&c->output),
482 packet_get_maxsize());
483 return 0;
484 }
485 }
486 }
487 return 1;
488 }
489
490 /* Returns true if any channel is still open. */
491 int
492 channel_still_open(void)
493 {
494 u_int i;
495 Channel *c;
496
497 for (i = 0; i < channels_alloc; i++) {
498 c = channels[i];
499 if (c == NULL)
500 continue;
501 switch (c->type) {
502 case SSH_CHANNEL_X11_LISTENER:
503 case SSH_CHANNEL_PORT_LISTENER:
504 case SSH_CHANNEL_RPORT_LISTENER:
505 case SSH_CHANNEL_CLOSED:
506 case SSH_CHANNEL_AUTH_SOCKET:
507 case SSH_CHANNEL_DYNAMIC:
508 case SSH_CHANNEL_CONNECTING:
509 case SSH_CHANNEL_ZOMBIE:
510 continue;
511 case SSH_CHANNEL_LARVAL:
512 if (!compat20)
513 fatal("cannot happen: SSH_CHANNEL_LARVAL");
514 continue;
515 case SSH_CHANNEL_OPENING:
516 case SSH_CHANNEL_OPEN:
517 case SSH_CHANNEL_X11_OPEN:
518 return 1;
519 case SSH_CHANNEL_INPUT_DRAINING:
520 case SSH_CHANNEL_OUTPUT_DRAINING:
521 if (!compat13)
522 fatal("cannot happen: OUT_DRAIN");
523 return 1;
524 default:
525 fatal("channel_still_open: bad channel type %d", c->type);
526 /* NOTREACHED */
527 }
528 }
529 return 0;
530 }
531
532 /* Returns the id of an open channel suitable for keepaliving */
533 int
534 channel_find_open(void)
535 {
536 u_int i;
537 Channel *c;
538
539 for (i = 0; i < channels_alloc; i++) {
540 c = channels[i];
541 if (c == NULL || c->remote_id < 0)
542 continue;
543 switch (c->type) {
544 case SSH_CHANNEL_CLOSED:
545 case SSH_CHANNEL_DYNAMIC:
546 case SSH_CHANNEL_X11_LISTENER:
547 case SSH_CHANNEL_PORT_LISTENER:
548 case SSH_CHANNEL_RPORT_LISTENER:
549 case SSH_CHANNEL_OPENING:
550 case SSH_CHANNEL_CONNECTING:
551 case SSH_CHANNEL_ZOMBIE:
552 continue;
553 case SSH_CHANNEL_LARVAL:
554 case SSH_CHANNEL_AUTH_SOCKET:
555 case SSH_CHANNEL_OPEN:
556 case SSH_CHANNEL_X11_OPEN:
557 return i;
558 case SSH_CHANNEL_INPUT_DRAINING:
559 case SSH_CHANNEL_OUTPUT_DRAINING:
560 if (!compat13)
561 fatal("cannot happen: OUT_DRAIN");
562 return i;
563 default:
564 fatal("channel_find_open: bad channel type %d", c->type);
565 /* NOTREACHED */
566 }
567 }
568 return -1;
569 }
570
571
572 /*
573 * Returns a message describing the currently open forwarded connections,
574 * suitable for sending to the client. The message contains crlf pairs for
575 * newlines.
576 */
577 char *
578 channel_open_message(void)
579 {
580 Buffer buffer;
581 Channel *c;
582 char buf[1024], *cp;
583 u_int i;
584
585 buffer_init(&buffer);
586 snprintf(buf, sizeof buf, "The following connections are open:\r\n");
587 buffer_append(&buffer, buf, strlen(buf));
588 for (i = 0; i < channels_alloc; i++) {
589 c = channels[i];
590 if (c == NULL)
591 continue;
592 switch (c->type) {
593 case SSH_CHANNEL_X11_LISTENER:
594 case SSH_CHANNEL_PORT_LISTENER:
595 case SSH_CHANNEL_RPORT_LISTENER:
596 case SSH_CHANNEL_CLOSED:
597 case SSH_CHANNEL_AUTH_SOCKET:
598 case SSH_CHANNEL_ZOMBIE:
599 continue;
600 case SSH_CHANNEL_LARVAL:
601 case SSH_CHANNEL_OPENING:
602 case SSH_CHANNEL_CONNECTING:
603 case SSH_CHANNEL_DYNAMIC:
604 case SSH_CHANNEL_OPEN:
605 case SSH_CHANNEL_X11_OPEN:
606 case SSH_CHANNEL_INPUT_DRAINING:
607 case SSH_CHANNEL_OUTPUT_DRAINING:
608 snprintf(buf, sizeof buf,
609 " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d cfd %d)\r\n",
610 c->self, c->remote_name,
611 c->type, c->remote_id,
612 c->istate, buffer_len(&c->input),
613 c->ostate, buffer_len(&c->output),
614 c->rfd, c->wfd, c->ctl_fd);
615 buffer_append(&buffer, buf, strlen(buf));
616 continue;
617 default:
618 fatal("channel_open_message: bad channel type %d", c->type);
619 /* NOTREACHED */
620 }
621 }
622 buffer_append(&buffer, "\0", 1);
623 cp = xstrdup(buffer_ptr(&buffer));
624 buffer_free(&buffer);
625 return cp;
626 }
627
628 void
629 channel_send_open(int id)
630 {
631 Channel *c = channel_lookup(id);
632
633 if (c == NULL) {
634 logit("channel_send_open: %d: bad id", id);
635 return;
636 }
637 debug2("channel %d: send open", id);
638 packet_start(SSH2_MSG_CHANNEL_OPEN);
639 packet_put_cstring(c->ctype);
640 packet_put_int(c->self);
641 packet_put_int(c->local_window);
642 packet_put_int(c->local_maxpacket);
643 packet_send();
644 }
645
646 void
647 channel_request_start(int id, char *service, int wantconfirm)
648 {
649 Channel *c = channel_lookup(id);
650
651 if (c == NULL) {
652 logit("channel_request_start: %d: unknown channel id", id);
653 return;
654 }
655 debug2("channel %d: request %s confirm %d", id, service, wantconfirm);
656 packet_start(SSH2_MSG_CHANNEL_REQUEST);
657 packet_put_int(c->remote_id);
658 packet_put_cstring(service);
659 packet_put_char(wantconfirm);
660 }
661
662 void
663 channel_register_confirm(int id, channel_callback_fn *fn, void *ctx)
664 {
665 Channel *c = channel_lookup(id);
666
667 if (c == NULL) {
668 logit("channel_register_comfirm: %d: bad id", id);
669 return;
670 }
671 c->confirm = fn;
672 c->confirm_ctx = ctx;
673 }
674
675 void
676 channel_register_cleanup(int id, channel_callback_fn *fn, int do_close)
677 {
678 Channel *c = channel_by_id(id);
679
680 if (c == NULL) {
681 logit("channel_register_cleanup: %d: bad id", id);
682 return;
683 }
684 c->detach_user = fn;
685 c->detach_close = do_close;
686 }
687
688 void
689 channel_cancel_cleanup(int id)
690 {
691 Channel *c = channel_by_id(id);
692
693 if (c == NULL) {
694 logit("channel_cancel_cleanup: %d: bad id", id);
695 return;
696 }
697 c->detach_user = NULL;
698 c->detach_close = 0;
699 }
700
701 void
702 channel_register_filter(int id, channel_infilter_fn *ifn,
703 channel_outfilter_fn *ofn)
704 {
705 Channel *c = channel_lookup(id);
706
707 if (c == NULL) {
708 logit("channel_register_filter: %d: bad id", id);
709 return;
710 }
711 c->input_filter = ifn;
712 c->output_filter = ofn;
713 }
714
715 void
716 channel_set_fds(int id, int rfd, int wfd, int efd,
717 int extusage, int nonblock, u_int window_max)
718 {
719 Channel *c = channel_lookup(id);
720
721 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
722 fatal("channel_activate for non-larval channel %d.", id);
723 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
724 c->type = SSH_CHANNEL_OPEN;
725 c->local_window = c->local_window_max = window_max;
726 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
727 packet_put_int(c->remote_id);
728 packet_put_int(c->local_window);
729 packet_send();
730 }
731
732 /*
733 * 'channel_pre*' are called just before select() to add any bits relevant to
734 * channels in the select bitmasks.
735 */
736 /*
737 * 'channel_post*': perform any appropriate operations for channels which
738 * have events pending.
739 */
740 typedef void chan_fn(Channel *c, fd_set *readset, fd_set *writeset);
741 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
742 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
743
744 /* ARGSUSED */
745 static void
746 channel_pre_listener(Channel *c, fd_set *readset, fd_set *writeset)
747 {
748 FD_SET(c->sock, readset);
749 }
750
751 /* ARGSUSED */
752 static void
753 channel_pre_connecting(Channel *c, fd_set *readset, fd_set *writeset)
754 {
755 debug3("channel %d: waiting for connection", c->self);
756 FD_SET(c->sock, writeset);
757 }
758
759 static void
760 channel_pre_open_13(Channel *c, fd_set *readset, fd_set *writeset)
761 {
762 if (buffer_len(&c->input) < packet_get_maxsize())
763 FD_SET(c->sock, readset);
764 if (buffer_len(&c->output) > 0)
765 FD_SET(c->sock, writeset);
766 }
767
768 static void
769 channel_pre_open(Channel *c, fd_set *readset, fd_set *writeset)
770 {
771 u_int limit = compat20 ? c->remote_window : packet_get_maxsize();
772
773 if (c->istate == CHAN_INPUT_OPEN &&
774 limit > 0 &&
775 buffer_len(&c->input) < limit &&
776 buffer_check_alloc(&c->input, CHAN_RBUF))
777 FD_SET(c->rfd, readset);
778 if (c->ostate == CHAN_OUTPUT_OPEN ||
779 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
780 if (buffer_len(&c->output) > 0) {
781 FD_SET(c->wfd, writeset);
782 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
783 if (CHANNEL_EFD_OUTPUT_ACTIVE(c))
784 debug2("channel %d: obuf_empty delayed efd %d/(%d)",
785 c->self, c->efd, buffer_len(&c->extended));
786 else
787 chan_obuf_empty(c);
788 }
789 }
790 /** XXX check close conditions, too */
791 if (compat20 && c->efd != -1) {
792 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
793 buffer_len(&c->extended) > 0)
794 FD_SET(c->efd, writeset);
795 else if (!(c->flags & CHAN_EOF_SENT) &&
796 c->extended_usage == CHAN_EXTENDED_READ &&
797 buffer_len(&c->extended) < c->remote_window)
798 FD_SET(c->efd, readset);
799 }
800 /* XXX: What about efd? races? */
801 if (compat20 && c->ctl_fd != -1 &&
802 c->istate == CHAN_INPUT_OPEN && c->ostate == CHAN_OUTPUT_OPEN)
803 FD_SET(c->ctl_fd, readset);
804 }
805
806 /* ARGSUSED */
807 static void
808 channel_pre_input_draining(Channel *c, fd_set *readset, fd_set *writeset)
809 {
810 if (buffer_len(&c->input) == 0) {
811 packet_start(SSH_MSG_CHANNEL_CLOSE);
812 packet_put_int(c->remote_id);
813 packet_send();
814 c->type = SSH_CHANNEL_CLOSED;
815 debug2("channel %d: closing after input drain.", c->self);
816 }
817 }
818
819 /* ARGSUSED */
820 static void
821 channel_pre_output_draining(Channel *c, fd_set *readset, fd_set *writeset)
822 {
823 if (buffer_len(&c->output) == 0)
824 chan_mark_dead(c);
825 else
826 FD_SET(c->sock, writeset);
827 }
828
829 /*
830 * This is a special state for X11 authentication spoofing. An opened X11
831 * connection (when authentication spoofing is being done) remains in this
832 * state until the first packet has been completely read. The authentication
833 * data in that packet is then substituted by the real data if it matches the
834 * fake data, and the channel is put into normal mode.
835 * XXX All this happens at the client side.
836 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
837 */
838 static int
839 x11_open_helper(Buffer *b)
840 {
841 u_char *ucp;
842 u_int proto_len, data_len;
843
844 /* Check if the fixed size part of the packet is in buffer. */
845 if (buffer_len(b) < 12)
846 return 0;
847
848 /* Parse the lengths of variable-length fields. */
849 ucp = buffer_ptr(b);
850 if (ucp[0] == 0x42) { /* Byte order MSB first. */
851 proto_len = 256 * ucp[6] + ucp[7];
852 data_len = 256 * ucp[8] + ucp[9];
853 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
854 proto_len = ucp[6] + 256 * ucp[7];
855 data_len = ucp[8] + 256 * ucp[9];
856 } else {
857 debug2("Initial X11 packet contains bad byte order byte: 0x%x",
858 ucp[0]);
859 return -1;
860 }
861
862 /* Check if the whole packet is in buffer. */
863 if (buffer_len(b) <
864 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
865 return 0;
866
867 /* Check if authentication protocol matches. */
868 if (proto_len != strlen(x11_saved_proto) ||
869 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
870 debug2("X11 connection uses different authentication protocol.");
871 return -1;
872 }
873 /* Check if authentication data matches our fake data. */
874 if (data_len != x11_fake_data_len ||
875 memcmp(ucp + 12 + ((proto_len + 3) & ~3),
876 x11_fake_data, x11_fake_data_len) != 0) {
877 debug2("X11 auth data does not match fake data.");
878 return -1;
879 }
880 /* Check fake data length */
881 if (x11_fake_data_len != x11_saved_data_len) {
882 error("X11 fake_data_len %d != saved_data_len %d",
883 x11_fake_data_len, x11_saved_data_len);
884 return -1;
885 }
886 /*
887 * Received authentication protocol and data match
888 * our fake data. Substitute the fake data with real
889 * data.
890 */
891 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
892 x11_saved_data, x11_saved_data_len);
893 return 1;
894 }
895
896 static void
897 channel_pre_x11_open_13(Channel *c, fd_set *readset, fd_set *writeset)
898 {
899 int ret = x11_open_helper(&c->output);
900
901 if (ret == 1) {
902 /* Start normal processing for the channel. */
903 c->type = SSH_CHANNEL_OPEN;
904 channel_pre_open_13(c, readset, writeset);
905 } else if (ret == -1) {
906 /*
907 * We have received an X11 connection that has bad
908 * authentication information.
909 */
910 logit("X11 connection rejected because of wrong authentication.");
911 buffer_clear(&c->input);
912 buffer_clear(&c->output);
913 channel_close_fd(&c->sock);
914 c->sock = -1;
915 c->type = SSH_CHANNEL_CLOSED;
916 packet_start(SSH_MSG_CHANNEL_CLOSE);
917 packet_put_int(c->remote_id);
918 packet_send();
919 }
920 }
921
922 static void
923 channel_pre_x11_open(Channel *c, fd_set *readset, fd_set *writeset)
924 {
925 int ret = x11_open_helper(&c->output);
926
927 /* c->force_drain = 1; */
928
929 if (ret == 1) {
930 c->type = SSH_CHANNEL_OPEN;
931 channel_pre_open(c, readset, writeset);
932 } else if (ret == -1) {
933 logit("X11 connection rejected because of wrong authentication.");
934 debug2("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
935 chan_read_failed(c);
936 buffer_clear(&c->input);
937 chan_ibuf_empty(c);
938 buffer_clear(&c->output);
939 /* for proto v1, the peer will send an IEOF */
940 if (compat20)
941 chan_write_failed(c);
942 else
943 c->type = SSH_CHANNEL_OPEN;
944 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
945 }
946 }
947
948 /* try to decode a socks4 header */
949 /* ARGSUSED */
950 static int
951 channel_decode_socks4(Channel *c, fd_set *readset, fd_set *writeset)
952 {
953 char *p, *host;
954 u_int len, have, i, found;
955 char username[256];
956 struct {
957 u_int8_t version;
958 u_int8_t command;
959 u_int16_t dest_port;
960 struct in_addr dest_addr;
961 } s4_req, s4_rsp;
962
963 debug2("channel %d: decode socks4", c->self);
964
965 have = buffer_len(&c->input);
966 len = sizeof(s4_req);
967 if (have < len)
968 return 0;
969 p = buffer_ptr(&c->input);
970 for (found = 0, i = len; i < have; i++) {
971 if (p[i] == '\0') {
972 found = 1;
973 break;
974 }
975 if (i > 1024) {
976 /* the peer is probably sending garbage */
977 debug("channel %d: decode socks4: too long",
978 c->self);
979 return -1;
980 }
981 }
982 if (!found)
983 return 0;
984 buffer_get(&c->input, (char *)&s4_req.version, 1);
985 buffer_get(&c->input, (char *)&s4_req.command, 1);
986 buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
987 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
988 have = buffer_len(&c->input);
989 p = buffer_ptr(&c->input);
990 len = strlen(p);
991 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
992 if (len > have)
993 fatal("channel %d: decode socks4: len %d > have %d",
994 c->self, len, have);
995 strlcpy(username, p, sizeof(username));
996 buffer_consume(&c->input, len);
997 buffer_consume(&c->input, 1); /* trailing '\0' */
998
999 host = inet_ntoa(s4_req.dest_addr);
1000 strlcpy(c->path, host, sizeof(c->path));
1001 c->host_port = ntohs(s4_req.dest_port);
1002
1003 debug2("channel %d: dynamic request: socks4 host %s port %u command %u",
1004 c->self, host, c->host_port, s4_req.command);
1005
1006 if (s4_req.command != 1) {
1007 debug("channel %d: cannot handle: socks4 cn %d",
1008 c->self, s4_req.command);
1009 return -1;
1010 }
1011 s4_rsp.version = 0; /* vn: 0 for reply */
1012 s4_rsp.command = 90; /* cd: req granted */
1013 s4_rsp.dest_port = 0; /* ignored */
1014 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
1015 buffer_append(&c->output, &s4_rsp, sizeof(s4_rsp));
1016 return 1;
1017 }
1018
1019 /* try to decode a socks5 header */
1020 #define SSH_SOCKS5_AUTHDONE 0x1000
1021 #define SSH_SOCKS5_NOAUTH 0x00
1022 #define SSH_SOCKS5_IPV4 0x01
1023 #define SSH_SOCKS5_DOMAIN 0x03
1024 #define SSH_SOCKS5_IPV6 0x04
1025 #define SSH_SOCKS5_CONNECT 0x01
1026 #define SSH_SOCKS5_SUCCESS 0x00
1027
1028 /* ARGSUSED */
1029 static int
1030 channel_decode_socks5(Channel *c, fd_set *readset, fd_set *writeset)
1031 {
1032 struct {
1033 u_int8_t version;
1034 u_int8_t command;
1035 u_int8_t reserved;
1036 u_int8_t atyp;
1037 } s5_req, s5_rsp;
1038 u_int16_t dest_port;
1039 u_char *p, dest_addr[255+1];
1040 u_int have, need, i, found, nmethods, addrlen, af;
1041
1042 debug2("channel %d: decode socks5", c->self);
1043 p = buffer_ptr(&c->input);
1044 if (p[0] != 0x05)
1045 return -1;
1046 have = buffer_len(&c->input);
1047 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) {
1048 /* format: ver | nmethods | methods */
1049 if (have < 2)
1050 return 0;
1051 nmethods = p[1];
1052 if (have < nmethods + 2)
1053 return 0;
1054 /* look for method: "NO AUTHENTICATION REQUIRED" */
1055 for (found = 0, i = 2; i < nmethods + 2; i++) {
1056 if (p[i] == SSH_SOCKS5_NOAUTH) {
1057 found = 1;
1058 break;
1059 }
1060 }
1061 if (!found) {
1062 debug("channel %d: method SSH_SOCKS5_NOAUTH not found",
1063 c->self);
1064 return -1;
1065 }
1066 buffer_consume(&c->input, nmethods + 2);
1067 buffer_put_char(&c->output, 0x05); /* version */
1068 buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH); /* method */
1069 FD_SET(c->sock, writeset);
1070 c->flags |= SSH_SOCKS5_AUTHDONE;
1071 debug2("channel %d: socks5 auth done", c->self);
1072 return 0; /* need more */
1073 }
1074 debug2("channel %d: socks5 post auth", c->self);
1075 if (have < sizeof(s5_req)+1)
1076 return 0; /* need more */
1077 memcpy(&s5_req, p, sizeof(s5_req));
1078 if (s5_req.version != 0x05 ||
1079 s5_req.command != SSH_SOCKS5_CONNECT ||
1080 s5_req.reserved != 0x00) {
1081 debug2("channel %d: only socks5 connect supported", c->self);
1082 return -1;
1083 }
1084 switch (s5_req.atyp){
1085 case SSH_SOCKS5_IPV4:
1086 addrlen = 4;
1087 af = AF_INET;
1088 break;
1089 case SSH_SOCKS5_DOMAIN:
1090 addrlen = p[sizeof(s5_req)];
1091 af = -1;
1092 break;
1093 case SSH_SOCKS5_IPV6:
1094 addrlen = 16;
1095 af = AF_INET6;
1096 break;
1097 default:
1098 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp);
1099 return -1;
1100 }
1101 need = sizeof(s5_req) + addrlen + 2;
1102 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1103 need++;
1104 if (have < need)
1105 return 0;
1106 buffer_consume(&c->input, sizeof(s5_req));
1107 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1108 buffer_consume(&c->input, 1); /* host string length */
1109 buffer_get(&c->input, (char *)&dest_addr, addrlen);
1110 buffer_get(&c->input, (char *)&dest_port, 2);
1111 dest_addr[addrlen] = '\0';
1112 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1113 strlcpy(c->path, (char *)dest_addr, sizeof(c->path));
1114 else if (inet_ntop(af, dest_addr, c->path, sizeof(c->path)) == NULL)
1115 return -1;
1116 c->host_port = ntohs(dest_port);
1117
1118 debug2("channel %d: dynamic request: socks5 host %s port %u command %u",
1119 c->self, c->path, c->host_port, s5_req.command);
1120
1121 s5_rsp.version = 0x05;
1122 s5_rsp.command = SSH_SOCKS5_SUCCESS;
1123 s5_rsp.reserved = 0; /* ignored */
1124 s5_rsp.atyp = SSH_SOCKS5_IPV4;
1125 ((struct in_addr *)&dest_addr)->s_addr = INADDR_ANY;
1126 dest_port = 0; /* ignored */
1127
1128 buffer_append(&c->output, &s5_rsp, sizeof(s5_rsp));
1129 buffer_append(&c->output, &dest_addr, sizeof(struct in_addr));
1130 buffer_append(&c->output, &dest_port, sizeof(dest_port));
1131 return 1;
1132 }
1133
1134 /* dynamic port forwarding */
1135 static void
1136 channel_pre_dynamic(Channel *c, fd_set *readset, fd_set *writeset)
1137 {
1138 u_char *p;
1139 u_int have;
1140 int ret;
1141
1142 have = buffer_len(&c->input);
1143 c->delayed = 0;
1144 debug2("channel %d: pre_dynamic: have %d", c->self, have);
1145 /* buffer_dump(&c->input); */
1146 /* check if the fixed size part of the packet is in buffer. */
1147 if (have < 3) {
1148 /* need more */
1149 FD_SET(c->sock, readset);
1150 return;
1151 }
1152 /* try to guess the protocol */
1153 p = buffer_ptr(&c->input);
1154 switch (p[0]) {
1155 case 0x04:
1156 ret = channel_decode_socks4(c, readset, writeset);
1157 break;
1158 case 0x05:
1159 ret = channel_decode_socks5(c, readset, writeset);
1160 break;
1161 default:
1162 ret = -1;
1163 break;
1164 }
1165 if (ret < 0) {
1166 chan_mark_dead(c);
1167 } else if (ret == 0) {
1168 debug2("channel %d: pre_dynamic: need more", c->self);
1169 /* need more */
1170 FD_SET(c->sock, readset);
1171 } else {
1172 /* switch to the next state */
1173 c->type = SSH_CHANNEL_OPENING;
1174 port_open_helper(c, "direct-tcpip");
1175 }
1176 }
1177
1178 /* This is our fake X11 server socket. */
1179 /* ARGSUSED */
1180 static void
1181 channel_post_x11_listener(Channel *c, fd_set *readset, fd_set *writeset)
1182 {
1183 Channel *nc;
1184 struct sockaddr addr;
1185 int newsock;
1186 socklen_t addrlen;
1187 char buf[16384], *remote_ipaddr;
1188 int remote_port;
1189
1190 if (FD_ISSET(c->sock, readset)) {
1191 debug("X11 connection requested.");
1192 addrlen = sizeof(addr);
1193 newsock = accept(c->sock, &addr, &addrlen);
1194 if (c->single_connection) {
1195 debug2("single_connection: closing X11 listener.");
1196 channel_close_fd(&c->sock);
1197 chan_mark_dead(c);
1198 }
1199 if (newsock < 0) {
1200 error("accept: %.100s", strerror(errno));
1201 return;
1202 }
1203 set_nodelay(newsock);
1204 remote_ipaddr = get_peer_ipaddr(newsock);
1205 remote_port = get_peer_port(newsock);
1206 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1207 remote_ipaddr, remote_port);
1208
1209 nc = channel_new("accepted x11 socket",
1210 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1211 c->local_window_max, c->local_maxpacket, 0, buf, 1);
1212 if (compat20) {
1213 packet_start(SSH2_MSG_CHANNEL_OPEN);
1214 packet_put_cstring("x11");
1215 packet_put_int(nc->self);
1216 packet_put_int(nc->local_window_max);
1217 packet_put_int(nc->local_maxpacket);
1218 /* originator ipaddr and port */
1219 packet_put_cstring(remote_ipaddr);
1220 if (datafellows & SSH_BUG_X11FWD) {
1221 debug2("ssh2 x11 bug compat mode");
1222 } else {
1223 packet_put_int(remote_port);
1224 }
1225 packet_send();
1226 } else {
1227 packet_start(SSH_SMSG_X11_OPEN);
1228 packet_put_int(nc->self);
1229 if (packet_get_protocol_flags() &
1230 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1231 packet_put_cstring(buf);
1232 packet_send();
1233 }
1234 xfree(remote_ipaddr);
1235 }
1236 }
1237
1238 static void
1239 port_open_helper(Channel *c, char *rtype)
1240 {
1241 int direct;
1242 char buf[1024];
1243 char *remote_ipaddr = get_peer_ipaddr(c->sock);
1244 int remote_port = get_peer_port(c->sock);
1245
1246 direct = (strcmp(rtype, "direct-tcpip") == 0);
1247
1248 snprintf(buf, sizeof buf,
1249 "%s: listening port %d for %.100s port %d, "
1250 "connect from %.200s port %d",
1251 rtype, c->listening_port, c->path, c->host_port,
1252 remote_ipaddr, remote_port);
1253
1254 xfree(c->remote_name);
1255 c->remote_name = xstrdup(buf);
1256
1257 if (compat20) {
1258 packet_start(SSH2_MSG_CHANNEL_OPEN);
1259 packet_put_cstring(rtype);
1260 packet_put_int(c->self);
1261 packet_put_int(c->local_window_max);
1262 packet_put_int(c->local_maxpacket);
1263 if (direct) {
1264 /* target host, port */
1265 packet_put_cstring(c->path);
1266 packet_put_int(c->host_port);
1267 } else {
1268 /* listen address, port */
1269 packet_put_cstring(c->path);
1270 packet_put_int(c->listening_port);
1271 }
1272 /* originator host and port */
1273 packet_put_cstring(remote_ipaddr);
1274 packet_put_int((u_int)remote_port);
1275 packet_send();
1276 } else {
1277 packet_start(SSH_MSG_PORT_OPEN);
1278 packet_put_int(c->self);
1279 packet_put_cstring(c->path);
1280 packet_put_int(c->host_port);
1281 if (packet_get_protocol_flags() &
1282 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1283 packet_put_cstring(c->remote_name);
1284 packet_send();
1285 }
1286 xfree(remote_ipaddr);
1287 }
1288
1289 static void
1290 channel_set_reuseaddr(int fd)
1291 {
1292 int on = 1;
1293
1294 /*
1295 * Set socket options.
1296 * Allow local port reuse in TIME_WAIT.
1297 */
1298 if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1)
1299 error("setsockopt SO_REUSEADDR fd %d: %s", fd, strerror(errno));
1300 }
1301
1302 /*
1303 * This socket is listening for connections to a forwarded TCP/IP port.
1304 */
1305 /* ARGSUSED */
1306 static void
1307 channel_post_port_listener(Channel *c, fd_set *readset, fd_set *writeset)
1308 {
1309 Channel *nc;
1310 struct sockaddr addr;
1311 int newsock, nextstate;
1312 socklen_t addrlen;
1313 char *rtype;
1314
1315 if (FD_ISSET(c->sock, readset)) {
1316 debug("Connection to port %d forwarding "
1317 "to %.100s port %d requested.",
1318 c->listening_port, c->path, c->host_port);
1319
1320 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1321 nextstate = SSH_CHANNEL_OPENING;
1322 rtype = "forwarded-tcpip";
1323 } else {
1324 if (c->host_port == 0) {
1325 nextstate = SSH_CHANNEL_DYNAMIC;
1326 rtype = "dynamic-tcpip";
1327 } else {
1328 nextstate = SSH_CHANNEL_OPENING;
1329 rtype = "direct-tcpip";
1330 }
1331 }
1332
1333 addrlen = sizeof(addr);
1334 newsock = accept(c->sock, &addr, &addrlen);
1335 if (newsock < 0) {
1336 error("accept: %.100s", strerror(errno));
1337 return;
1338 }
1339 set_nodelay(newsock);
1340 nc = channel_new(rtype, nextstate, newsock, newsock, -1,
1341 c->local_window_max, c->local_maxpacket, 0, rtype, 1);
1342 nc->listening_port = c->listening_port;
1343 nc->host_port = c->host_port;
1344 strlcpy(nc->path, c->path, sizeof(nc->path));
1345
1346 if (nextstate == SSH_CHANNEL_DYNAMIC) {
1347 /*
1348 * do not call the channel_post handler until
1349 * this flag has been reset by a pre-handler.
1350 * otherwise the FD_ISSET calls might overflow
1351 */
1352 nc->delayed = 1;
1353 } else {
1354 port_open_helper(nc, rtype);
1355 }
1356 }
1357 }
1358
1359 /*
1360 * This is the authentication agent socket listening for connections from
1361 * clients.
1362 */
1363 /* ARGSUSED */
1364 static void
1365 channel_post_auth_listener(Channel *c, fd_set *readset, fd_set *writeset)
1366 {
1367 Channel *nc;
1368 int newsock;
1369 struct sockaddr addr;
1370 socklen_t addrlen;
1371
1372 if (FD_ISSET(c->sock, readset)) {
1373 addrlen = sizeof(addr);
1374 newsock = accept(c->sock, &addr, &addrlen);
1375 if (newsock < 0) {
1376 error("accept from auth socket: %.100s", strerror(errno));
1377 return;
1378 }
1379 nc = channel_new("accepted auth socket",
1380 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1381 c->local_window_max, c->local_maxpacket,
1382 0, "accepted auth socket", 1);
1383 if (compat20) {
1384 packet_start(SSH2_MSG_CHANNEL_OPEN);
1385 packet_put_cstring("auth-agent@openssh.com");
1386 packet_put_int(nc->self);
1387 packet_put_int(c->local_window_max);
1388 packet_put_int(c->local_maxpacket);
1389 } else {
1390 packet_start(SSH_SMSG_AGENT_OPEN);
1391 packet_put_int(nc->self);
1392 }
1393 packet_send();
1394 }
1395 }
1396
1397 /* ARGSUSED */
1398 static void
1399 channel_post_connecting(Channel *c, fd_set *readset, fd_set *writeset)
1400 {
1401 int err = 0;
1402 socklen_t sz = sizeof(err);
1403
1404 if (FD_ISSET(c->sock, writeset)) {
1405 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) {
1406 err = errno;
1407 error("getsockopt SO_ERROR failed");
1408 }
1409 if (err == 0) {
1410 debug("channel %d: connected", c->self);
1411 c->type = SSH_CHANNEL_OPEN;
1412 if (compat20) {
1413 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1414 packet_put_int(c->remote_id);
1415 packet_put_int(c->self);
1416 packet_put_int(c->local_window);
1417 packet_put_int(c->local_maxpacket);
1418 } else {
1419 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1420 packet_put_int(c->remote_id);
1421 packet_put_int(c->self);
1422 }
1423 } else {
1424 debug("channel %d: not connected: %s",
1425 c->self, strerror(err));
1426 if (compat20) {
1427 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1428 packet_put_int(c->remote_id);
1429 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1430 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1431 packet_put_cstring(strerror(err));
1432 packet_put_cstring("");
1433 }
1434 } else {
1435 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1436 packet_put_int(c->remote_id);
1437 }
1438 chan_mark_dead(c);
1439 }
1440 packet_send();
1441 }
1442 }
1443
1444 /* ARGSUSED */
1445 static int
1446 channel_handle_rfd(Channel *c, fd_set *readset, fd_set *writeset)
1447 {
1448 char buf[CHAN_RBUF];
1449 int len, force;
1450
1451 force = c->isatty && c->detach_close && c->istate != CHAN_INPUT_CLOSED;
1452 if (c->rfd != -1 && (force || FD_ISSET(c->rfd, readset))) {
1453 errno = 0;
1454 len = read(c->rfd, buf, sizeof(buf));
1455 if (len < 0 && (errno == EINTR || (errno == EAGAIN && !force)))
1456 return 1;
1457 #ifndef PTY_ZEROREAD
1458 if (len <= 0) {
1459 #else
1460 if ((!c->isatty && len <= 0) ||
1461 (c->isatty && (len < 0 || (len == 0 && errno != 0)))) {
1462 #endif
1463 debug2("channel %d: read<=0 rfd %d len %d",
1464 c->self, c->rfd, len);
1465 if (c->type != SSH_CHANNEL_OPEN) {
1466 debug2("channel %d: not open", c->self);
1467 chan_mark_dead(c);
1468 return -1;
1469 } else if (compat13) {
1470 buffer_clear(&c->output);
1471 c->type = SSH_CHANNEL_INPUT_DRAINING;
1472 debug2("channel %d: input draining.", c->self);
1473 } else {
1474 chan_read_failed(c);
1475 }
1476 return -1;
1477 }
1478 if (c->input_filter != NULL) {
1479 if (c->input_filter(c, buf, len) == -1) {
1480 debug2("channel %d: filter stops", c->self);
1481 chan_read_failed(c);
1482 }
1483 } else if (c->datagram) {
1484 buffer_put_string(&c->input, buf, len);
1485 } else {
1486 buffer_append(&c->input, buf, len);
1487 }
1488 }
1489 return 1;
1490 }
1491
1492 /* ARGSUSED */
1493 static int
1494 channel_handle_wfd(Channel *c, fd_set *readset, fd_set *writeset)
1495 {
1496 struct termios tio;
1497 u_char *data = NULL, *buf;
1498 u_int dlen;
1499 int len;
1500
1501 /* Send buffered output data to the socket. */
1502 if (c->wfd != -1 &&
1503 FD_ISSET(c->wfd, writeset) &&
1504 buffer_len(&c->output) > 0) {
1505 if (c->output_filter != NULL) {
1506 if ((buf = c->output_filter(c, &data, &dlen)) == NULL) {
1507 debug2("channel %d: filter stops", c->self);
1508 if (c->type != SSH_CHANNEL_OPEN)
1509 chan_mark_dead(c);
1510 else
1511 chan_write_failed(c);
1512 return -1;
1513 }
1514 } else if (c->datagram) {
1515 buf = data = buffer_get_string(&c->output, &dlen);
1516 } else {
1517 buf = data = buffer_ptr(&c->output);
1518 dlen = buffer_len(&c->output);
1519 }
1520
1521 if (c->datagram) {
1522 /* ignore truncated writes, datagrams might get lost */
1523 c->local_consumed += dlen + 4;
1524 len = write(c->wfd, buf, dlen);
1525 xfree(data);
1526 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1527 return 1;
1528 if (len <= 0) {
1529 if (c->type != SSH_CHANNEL_OPEN)
1530 chan_mark_dead(c);
1531 else
1532 chan_write_failed(c);
1533 return -1;
1534 }
1535 return 1;
1536 }
1537 #ifdef _AIX
1538 /* XXX: Later AIX versions can't push as much data to tty */
1539 if (compat20 && c->wfd_isatty)
1540 dlen = MIN(dlen, 8*1024);
1541 #endif
1542
1543 len = write(c->wfd, buf, dlen);
1544 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1545 return 1;
1546 if (len <= 0) {
1547 if (c->type != SSH_CHANNEL_OPEN) {
1548 debug2("channel %d: not open", c->self);
1549 chan_mark_dead(c);
1550 return -1;
1551 } else if (compat13) {
1552 buffer_clear(&c->output);
1553 debug2("channel %d: input draining.", c->self);
1554 c->type = SSH_CHANNEL_INPUT_DRAINING;
1555 } else {
1556 chan_write_failed(c);
1557 }
1558 return -1;
1559 }
1560 if (compat20 && c->isatty && dlen >= 1 && buf[0] != '\r') {
1561 if (tcgetattr(c->wfd, &tio) == 0 &&
1562 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1563 /*
1564 * Simulate echo to reduce the impact of
1565 * traffic analysis. We need to match the
1566 * size of a SSH2_MSG_CHANNEL_DATA message
1567 * (4 byte channel id + buf)
1568 */
1569 packet_send_ignore(4 + len);
1570 packet_send();
1571 }
1572 }
1573 buffer_consume(&c->output, len);
1574 if (compat20 && len > 0) {
1575 c->local_consumed += len;
1576 }
1577 }
1578 return 1;
1579 }
1580
1581 static int
1582 channel_handle_efd(Channel *c, fd_set *readset, fd_set *writeset)
1583 {
1584 char buf[CHAN_RBUF];
1585 int len;
1586
1587 /** XXX handle drain efd, too */
1588 if (c->efd != -1) {
1589 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1590 FD_ISSET(c->efd, writeset) &&
1591 buffer_len(&c->extended) > 0) {
1592 len = write(c->efd, buffer_ptr(&c->extended),
1593 buffer_len(&c->extended));
1594 debug2("channel %d: written %d to efd %d",
1595 c->self, len, c->efd);
1596 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1597 return 1;
1598 if (len <= 0) {
1599 debug2("channel %d: closing write-efd %d",
1600 c->self, c->efd);
1601 channel_close_fd(&c->efd);
1602 } else {
1603 buffer_consume(&c->extended, len);
1604 c->local_consumed += len;
1605 }
1606 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
1607 (c->detach_close || FD_ISSET(c->efd, readset))) {
1608 len = read(c->efd, buf, sizeof(buf));
1609 debug2("channel %d: read %d from efd %d",
1610 c->self, len, c->efd);
1611 if (len < 0 && (errno == EINTR ||
1612 (errno == EAGAIN && !c->detach_close)))
1613 return 1;
1614 if (len <= 0) {
1615 debug2("channel %d: closing read-efd %d",
1616 c->self, c->efd);
1617 channel_close_fd(&c->efd);
1618 } else {
1619 buffer_append(&c->extended, buf, len);
1620 }
1621 }
1622 }
1623 return 1;
1624 }
1625
1626 /* ARGSUSED */
1627 static int
1628 channel_handle_ctl(Channel *c, fd_set *readset, fd_set *writeset)
1629 {
1630 char buf[16];
1631 int len;
1632
1633 /* Monitor control fd to detect if the slave client exits */
1634 if (c->ctl_fd != -1 && FD_ISSET(c->ctl_fd, readset)) {
1635 len = read(c->ctl_fd, buf, sizeof(buf));
1636 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1637 return 1;
1638 if (len <= 0) {
1639 debug2("channel %d: ctl read<=0", c->self);
1640 if (c->type != SSH_CHANNEL_OPEN) {
1641 debug2("channel %d: not open", c->self);
1642 chan_mark_dead(c);
1643 return -1;
1644 } else {
1645 chan_read_failed(c);
1646 chan_write_failed(c);
1647 }
1648 return -1;
1649 } else
1650 fatal("%s: unexpected data on ctl fd", __func__);
1651 }
1652 return 1;
1653 }
1654
1655 static int
1656 channel_check_window(Channel *c)
1657 {
1658 if (c->type == SSH_CHANNEL_OPEN &&
1659 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1660 ((c->local_window_max - c->local_window >
1661 c->local_maxpacket*3) ||
1662 c->local_window < c->local_window_max/2) &&
1663 c->local_consumed > 0) {
1664 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1665 packet_put_int(c->remote_id);
1666 packet_put_int(c->local_consumed);
1667 packet_send();
1668 debug2("channel %d: window %d sent adjust %d",
1669 c->self, c->local_window,
1670 c->local_consumed);
1671 c->local_window += c->local_consumed;
1672 c->local_consumed = 0;
1673 }
1674 return 1;
1675 }
1676
1677 static void
1678 channel_post_open(Channel *c, fd_set *readset, fd_set *writeset)
1679 {
1680 if (c->delayed)
1681 return;
1682 channel_handle_rfd(c, readset, writeset);
1683 channel_handle_wfd(c, readset, writeset);
1684 if (!compat20)
1685 return;
1686 channel_handle_efd(c, readset, writeset);
1687 channel_handle_ctl(c, readset, writeset);
1688 channel_check_window(c);
1689 }
1690
1691 /* ARGSUSED */
1692 static void
1693 channel_post_output_drain_13(Channel *c, fd_set *readset, fd_set *writeset)
1694 {
1695 int len;
1696
1697 /* Send buffered output data to the socket. */
1698 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1699 len = write(c->sock, buffer_ptr(&c->output),
1700 buffer_len(&c->output));
1701 if (len <= 0)
1702 buffer_clear(&c->output);
1703 else
1704 buffer_consume(&c->output, len);
1705 }
1706 }
1707
1708 static void
1709 channel_handler_init_20(void)
1710 {
1711 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1712 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1713 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1714 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
1715 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1716 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1717 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1718 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1719
1720 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1721 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1722 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
1723 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1724 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1725 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1726 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1727 }
1728
1729 static void
1730 channel_handler_init_13(void)
1731 {
1732 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
1733 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
1734 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1735 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1736 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1737 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
1738 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1739 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1740 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1741
1742 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1743 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1744 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1745 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1746 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
1747 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1748 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1749 }
1750
1751 static void
1752 channel_handler_init_15(void)
1753 {
1754 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1755 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1756 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1757 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1758 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1759 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1760 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1761
1762 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1763 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1764 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1765 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1766 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1767 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1768 }
1769
1770 static void
1771 channel_handler_init(void)
1772 {
1773 int i;
1774
1775 for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
1776 channel_pre[i] = NULL;
1777 channel_post[i] = NULL;
1778 }
1779 if (compat20)
1780 channel_handler_init_20();
1781 else if (compat13)
1782 channel_handler_init_13();
1783 else
1784 channel_handler_init_15();
1785 }
1786
1787 /* gc dead channels */
1788 static void
1789 channel_garbage_collect(Channel *c)
1790 {
1791 if (c == NULL)
1792 return;
1793 if (c->detach_user != NULL) {
1794 if (!chan_is_dead(c, c->detach_close))
1795 return;
1796 debug2("channel %d: gc: notify user", c->self);
1797 c->detach_user(c->self, NULL);
1798 /* if we still have a callback */
1799 if (c->detach_user != NULL)
1800 return;
1801 debug2("channel %d: gc: user detached", c->self);
1802 }
1803 if (!chan_is_dead(c, 1))
1804 return;
1805 debug2("channel %d: garbage collecting", c->self);
1806 channel_free(c);
1807 }
1808
1809 static void
1810 channel_handler(chan_fn *ftab[], fd_set *readset, fd_set *writeset)
1811 {
1812 static int did_init = 0;
1813 u_int i;
1814 Channel *c;
1815
1816 if (!did_init) {
1817 channel_handler_init();
1818 did_init = 1;
1819 }
1820 for (i = 0; i < channels_alloc; i++) {
1821 c = channels[i];
1822 if (c == NULL)
1823 continue;
1824 if (ftab[c->type] != NULL)
1825 (*ftab[c->type])(c, readset, writeset);
1826 channel_garbage_collect(c);
1827 }
1828 }
1829
1830 /*
1831 * Allocate/update select bitmasks and add any bits relevant to channels in
1832 * select bitmasks.
1833 */
1834 void
1835 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
1836 u_int *nallocp, int rekeying)
1837 {
1838 u_int n, sz, nfdset;
1839
1840 n = MAX(*maxfdp, channel_max_fd);
1841
1842 nfdset = howmany(n+1, NFDBITS);
1843 /* Explicitly test here, because xrealloc isn't always called */
1844 if (nfdset && SIZE_T_MAX / nfdset < sizeof(fd_mask))
1845 fatal("channel_prepare_select: max_fd (%d) is too large", n);
1846 sz = nfdset * sizeof(fd_mask);
1847
1848 /* perhaps check sz < nalloc/2 and shrink? */
1849 if (*readsetp == NULL || sz > *nallocp) {
1850 *readsetp = xrealloc(*readsetp, nfdset, sizeof(fd_mask));
1851 *writesetp = xrealloc(*writesetp, nfdset, sizeof(fd_mask));
1852 *nallocp = sz;
1853 }
1854 *maxfdp = n;
1855 memset(*readsetp, 0, sz);
1856 memset(*writesetp, 0, sz);
1857
1858 if (!rekeying)
1859 channel_handler(channel_pre, *readsetp, *writesetp);
1860 }
1861
1862 /*
1863 * After select, perform any appropriate operations for channels which have
1864 * events pending.
1865 */
1866 void
1867 channel_after_select(fd_set *readset, fd_set *writeset)
1868 {
1869 channel_handler(channel_post, readset, writeset);
1870 }
1871
1872
1873 /* If there is data to send to the connection, enqueue some of it now. */
1874 void
1875 channel_output_poll(void)
1876 {
1877 Channel *c;
1878 u_int i, len;
1879
1880 for (i = 0; i < channels_alloc; i++) {
1881 c = channels[i];
1882 if (c == NULL)
1883 continue;
1884
1885 /*
1886 * We are only interested in channels that can have buffered
1887 * incoming data.
1888 */
1889 if (compat13) {
1890 if (c->type != SSH_CHANNEL_OPEN &&
1891 c->type != SSH_CHANNEL_INPUT_DRAINING)
1892 continue;
1893 } else {
1894 if (c->type != SSH_CHANNEL_OPEN)
1895 continue;
1896 }
1897 if (compat20 &&
1898 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
1899 /* XXX is this true? */
1900 debug3("channel %d: will not send data after close", c->self);
1901 continue;
1902 }
1903
1904 /* Get the amount of buffered data for this channel. */
1905 if ((c->istate == CHAN_INPUT_OPEN ||
1906 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
1907 (len = buffer_len(&c->input)) > 0) {
1908 if (c->datagram) {
1909 if (len > 0) {
1910 u_char *data;
1911 u_int dlen;
1912
1913 data = buffer_get_string(&c->input,
1914 &dlen);
1915 packet_start(SSH2_MSG_CHANNEL_DATA);
1916 packet_put_int(c->remote_id);
1917 packet_put_string(data, dlen);
1918 packet_send();
1919 c->remote_window -= dlen + 4;
1920 xfree(data);
1921 }
1922 continue;
1923 }
1924 /*
1925 * Send some data for the other side over the secure
1926 * connection.
1927 */
1928 if (compat20) {
1929 if (len > c->remote_window)
1930 len = c->remote_window;
1931 if (len > c->remote_maxpacket)
1932 len = c->remote_maxpacket;
1933 } else {
1934 if (packet_is_interactive()) {
1935 if (len > 1024)
1936 len = 512;
1937 } else {
1938 /* Keep the packets at reasonable size. */
1939 if (len > packet_get_maxsize()/2)
1940 len = packet_get_maxsize()/2;
1941 }
1942 }
1943 if (len > 0) {
1944 packet_start(compat20 ?
1945 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
1946 packet_put_int(c->remote_id);
1947 packet_put_string(buffer_ptr(&c->input), len);
1948 packet_send();
1949 buffer_consume(&c->input, len);
1950 c->remote_window -= len;
1951 }
1952 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1953 if (compat13)
1954 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
1955 /*
1956 * input-buffer is empty and read-socket shutdown:
1957 * tell peer, that we will not send more data: send IEOF.
1958 * hack for extended data: delay EOF if EFD still in use.
1959 */
1960 if (CHANNEL_EFD_INPUT_ACTIVE(c))
1961 debug2("channel %d: ibuf_empty delayed efd %d/(%d)",
1962 c->self, c->efd, buffer_len(&c->extended));
1963 else
1964 chan_ibuf_empty(c);
1965 }
1966 /* Send extended data, i.e. stderr */
1967 if (compat20 &&
1968 !(c->flags & CHAN_EOF_SENT) &&
1969 c->remote_window > 0 &&
1970 (len = buffer_len(&c->extended)) > 0 &&
1971 c->extended_usage == CHAN_EXTENDED_READ) {
1972 debug2("channel %d: rwin %u elen %u euse %d",
1973 c->self, c->remote_window, buffer_len(&c->extended),
1974 c->extended_usage);
1975 if (len > c->remote_window)
1976 len = c->remote_window;
1977 if (len > c->remote_maxpacket)
1978 len = c->remote_maxpacket;
1979 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
1980 packet_put_int(c->remote_id);
1981 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
1982 packet_put_string(buffer_ptr(&c->extended), len);
1983 packet_send();
1984 buffer_consume(&c->extended, len);
1985 c->remote_window -= len;
1986 debug2("channel %d: sent ext data %d", c->self, len);
1987 }
1988 }
1989 }
1990
1991
1992 /* -- protocol input */
1993
1994 /* ARGSUSED */
1995 void
1996 channel_input_data(int type, u_int32_t seq, void *ctxt)
1997 {
1998 int id;
1999 char *data;
2000 u_int data_len;
2001 Channel *c;
2002
2003 /* Get the channel number and verify it. */
2004 id = packet_get_int();
2005 c = channel_lookup(id);
2006 if (c == NULL)
2007 packet_disconnect("Received data for nonexistent channel %d.", id);
2008
2009 /* Ignore any data for non-open channels (might happen on close) */
2010 if (c->type != SSH_CHANNEL_OPEN &&
2011 c->type != SSH_CHANNEL_X11_OPEN)
2012 return;
2013
2014 /* Get the data. */
2015 data = packet_get_string(&data_len);
2016
2017 /*
2018 * Ignore data for protocol > 1.3 if output end is no longer open.
2019 * For protocol 2 the sending side is reducing its window as it sends
2020 * data, so we must 'fake' consumption of the data in order to ensure
2021 * that window updates are sent back. Otherwise the connection might
2022 * deadlock.
2023 */
2024 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) {
2025 if (compat20) {
2026 c->local_window -= data_len;
2027 c->local_consumed += data_len;
2028 }
2029 xfree(data);
2030 return;
2031 }
2032
2033 if (compat20) {
2034 if (data_len > c->local_maxpacket) {
2035 logit("channel %d: rcvd big packet %d, maxpack %d",
2036 c->self, data_len, c->local_maxpacket);
2037 }
2038 if (data_len > c->local_window) {
2039 logit("channel %d: rcvd too much data %d, win %d",
2040 c->self, data_len, c->local_window);
2041 xfree(data);
2042 return;
2043 }
2044 c->local_window -= data_len;
2045 }
2046 packet_check_eom();
2047 if (c->datagram)
2048 buffer_put_string(&c->output, data, data_len);
2049 else
2050 buffer_append(&c->output, data, data_len);
2051 xfree(data);
2052 }
2053
2054 /* ARGSUSED */
2055 void
2056 channel_input_extended_data(int type, u_int32_t seq, void *ctxt)
2057 {
2058 int id;
2059 char *data;
2060 u_int data_len, tcode;
2061 Channel *c;
2062
2063 /* Get the channel number and verify it. */
2064 id = packet_get_int();
2065 c = channel_lookup(id);
2066
2067 if (c == NULL)
2068 packet_disconnect("Received extended_data for bad channel %d.", id);
2069 if (c->type != SSH_CHANNEL_OPEN) {
2070 logit("channel %d: ext data for non open", id);
2071 return;
2072 }
2073 if (c->flags & CHAN_EOF_RCVD) {
2074 if (datafellows & SSH_BUG_EXTEOF)
2075 debug("channel %d: accepting ext data after eof", id);
2076 else
2077 packet_disconnect("Received extended_data after EOF "
2078 "on channel %d.", id);
2079 }
2080 tcode = packet_get_int();
2081 if (c->efd == -1 ||
2082 c->extended_usage != CHAN_EXTENDED_WRITE ||
2083 tcode != SSH2_EXTENDED_DATA_STDERR) {
2084 logit("channel %d: bad ext data", c->self);
2085 return;
2086 }
2087 data = packet_get_string(&data_len);
2088 packet_check_eom();
2089 if (data_len > c->local_window) {
2090 logit("channel %d: rcvd too much extended_data %d, win %d",
2091 c->self, data_len, c->local_window);
2092 xfree(data);
2093 return;
2094 }
2095 debug2("channel %d: rcvd ext data %d", c->self, data_len);
2096 c->local_window -= data_len;
2097 buffer_append(&c->extended, data, data_len);
2098 xfree(data);
2099 }
2100
2101 /* ARGSUSED */
2102 void
2103 channel_input_ieof(int type, u_int32_t seq, void *ctxt)
2104 {
2105 int id;
2106 Channel *c;
2107
2108 id = packet_get_int();
2109 packet_check_eom();
2110 c = channel_lookup(id);
2111 if (c == NULL)
2112 packet_disconnect("Received ieof for nonexistent channel %d.", id);
2113 chan_rcvd_ieof(c);
2114
2115 /* XXX force input close */
2116 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) {
2117 debug("channel %d: FORCE input drain", c->self);
2118 c->istate = CHAN_INPUT_WAIT_DRAIN;
2119 if (buffer_len(&c->input) == 0)
2120 chan_ibuf_empty(c);
2121 }
2122
2123 }
2124
2125 /* ARGSUSED */
2126 void
2127 channel_input_close(int type, u_int32_t seq, void *ctxt)
2128 {
2129 int id;
2130 Channel *c;
2131
2132 id = packet_get_int();
2133 packet_check_eom();
2134 c = channel_lookup(id);
2135 if (c == NULL)
2136 packet_disconnect("Received close for nonexistent channel %d.", id);
2137
2138 /*
2139 * Send a confirmation that we have closed the channel and no more
2140 * data is coming for it.
2141 */
2142 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
2143 packet_put_int(c->remote_id);
2144 packet_send();
2145
2146 /*
2147 * If the channel is in closed state, we have sent a close request,
2148 * and the other side will eventually respond with a confirmation.
2149 * Thus, we cannot free the channel here, because then there would be
2150 * no-one to receive the confirmation. The channel gets freed when
2151 * the confirmation arrives.
2152 */
2153 if (c->type != SSH_CHANNEL_CLOSED) {
2154 /*
2155 * Not a closed channel - mark it as draining, which will
2156 * cause it to be freed later.
2157 */
2158 buffer_clear(&c->input);
2159 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
2160 }
2161 }
2162
2163 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
2164 /* ARGSUSED */
2165 void
2166 channel_input_oclose(int type, u_int32_t seq, void *ctxt)
2167 {
2168 int id = packet_get_int();
2169 Channel *c = channel_lookup(id);
2170
2171 packet_check_eom();
2172 if (c == NULL)
2173 packet_disconnect("Received oclose for nonexistent channel %d.", id);
2174 chan_rcvd_oclose(c);
2175 }
2176
2177 /* ARGSUSED */
2178 void
2179 channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt)
2180 {
2181 int id = packet_get_int();
2182 Channel *c = channel_lookup(id);
2183
2184 packet_check_eom();
2185 if (c == NULL)
2186 packet_disconnect("Received close confirmation for "
2187 "out-of-range channel %d.", id);
2188 if (c->type != SSH_CHANNEL_CLOSED)
2189 packet_disconnect("Received close confirmation for "
2190 "non-closed channel %d (type %d).", id, c->type);
2191 channel_free(c);
2192 }
2193
2194 /* ARGSUSED */
2195 void
2196 channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt)
2197 {
2198 int id, remote_id;
2199 Channel *c;
2200
2201 id = packet_get_int();
2202 c = channel_lookup(id);
2203
2204 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2205 packet_disconnect("Received open confirmation for "
2206 "non-opening channel %d.", id);
2207 remote_id = packet_get_int();
2208 /* Record the remote channel number and mark that the channel is now open. */
2209 c->remote_id = remote_id;
2210 c->type = SSH_CHANNEL_OPEN;
2211
2212 if (compat20) {
2213 c->remote_window = packet_get_int();
2214 c->remote_maxpacket = packet_get_int();
2215 if (c->confirm) {
2216 debug2("callback start");
2217 c->confirm(c->self, c->confirm_ctx);
2218 debug2("callback done");
2219 }
2220 debug2("channel %d: open confirm rwindow %u rmax %u", c->self,
2221 c->remote_window, c->remote_maxpacket);
2222 }
2223 packet_check_eom();
2224 }
2225
2226 static char *
2227 reason2txt(int reason)
2228 {
2229 switch (reason) {
2230 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
2231 return "administratively prohibited";
2232 case SSH2_OPEN_CONNECT_FAILED:
2233 return "connect failed";
2234 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
2235 return "unknown channel type";
2236 case SSH2_OPEN_RESOURCE_SHORTAGE:
2237 return "resource shortage";
2238 }
2239 return "unknown reason";
2240 }
2241
2242 /* ARGSUSED */
2243 void
2244 channel_input_open_failure(int type, u_int32_t seq, void *ctxt)
2245 {
2246 int id, reason;
2247 char *msg = NULL, *lang = NULL;
2248 Channel *c;
2249
2250 id = packet_get_int();
2251 c = channel_lookup(id);
2252
2253 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2254 packet_disconnect("Received open failure for "
2255 "non-opening channel %d.", id);
2256 if (compat20) {
2257 reason = packet_get_int();
2258 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
2259 msg = packet_get_string(NULL);
2260 lang = packet_get_string(NULL);
2261 }
2262 logit("channel %d: open failed: %s%s%s", id,
2263 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
2264 if (msg != NULL)
2265 xfree(msg);
2266 if (lang != NULL)
2267 xfree(lang);
2268 }
2269 packet_check_eom();
2270 /* Free the channel. This will also close the socket. */
2271 channel_free(c);
2272 }
2273
2274 /* ARGSUSED */
2275 void
2276 channel_input_window_adjust(int type, u_int32_t seq, void *ctxt)
2277 {
2278 Channel *c;
2279 int id;
2280 u_int adjust;
2281
2282 if (!compat20)
2283 return;
2284
2285 /* Get the channel number and verify it. */
2286 id = packet_get_int();
2287 c = channel_lookup(id);
2288
2289 if (c == NULL) {
2290 logit("Received window adjust for non-open channel %d.", id);
2291 return;
2292 }
2293 adjust = packet_get_int();
2294 packet_check_eom();
2295 debug2("channel %d: rcvd adjust %u", id, adjust);
2296 c->remote_window += adjust;
2297 }
2298
2299 /* ARGSUSED */
2300 void
2301 channel_input_port_open(int type, u_int32_t seq, void *ctxt)
2302 {
2303 Channel *c = NULL;
2304 u_short host_port;
2305 char *host, *originator_string;
2306 int remote_id, sock = -1;
2307
2308 remote_id = packet_get_int();
2309 host = packet_get_string(NULL);
2310 host_port = packet_get_int();
2311
2312 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2313 originator_string = packet_get_string(NULL);
2314 } else {
2315 originator_string = xstrdup("unknown (remote did not supply name)");
2316 }
2317 packet_check_eom();
2318 sock = channel_connect_to(host, host_port);
2319 if (sock != -1) {
2320 c = channel_new("connected socket",
2321 SSH_CHANNEL_CONNECTING, sock, sock, -1, 0, 0, 0,
2322 originator_string, 1);
2323 c->remote_id = remote_id;
2324 }
2325 xfree(originator_string);
2326 if (c == NULL) {
2327 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2328 packet_put_int(remote_id);
2329 packet_send();
2330 }
2331 xfree(host);
2332 }
2333
2334
2335 /* -- tcp forwarding */
2336
2337 void
2338 channel_set_af(int af)
2339 {
2340 IPv4or6 = af;
2341 }
2342
2343 static int
2344 channel_setup_fwd_listener(int type, const char *listen_addr, u_short listen_port,
2345 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2346 {
2347 Channel *c;
2348 int sock, r, success = 0, wildcard = 0, is_client;
2349 struct addrinfo hints, *ai, *aitop;
2350 const char *host, *addr;
2351 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2352
2353 host = (type == SSH_CHANNEL_RPORT_LISTENER) ?
2354 listen_addr : host_to_connect;
2355 is_client = (type == SSH_CHANNEL_PORT_LISTENER);
2356
2357 if (host == NULL) {
2358 error("No forward host name.");
2359 return 0;
2360 }
2361 if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) {
2362 error("Forward host name too long.");
2363 return 0;
2364 }
2365
2366 /*
2367 * Determine whether or not a port forward listens to loopback,
2368 * specified address or wildcard. On the client, a specified bind
2369 * address will always override gateway_ports. On the server, a
2370 * gateway_ports of 1 (``yes'') will override the client's
2371 * specification and force a wildcard bind, whereas a value of 2
2372 * (``clientspecified'') will bind to whatever address the client
2373 * asked for.
2374 *
2375 * Special-case listen_addrs are:
2376 *
2377 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR
2378 * "" (empty string), "*" -> wildcard v4/v6
2379 * "localhost" -> loopback v4/v6
2380 */
2381 addr = NULL;
2382 if (listen_addr == NULL) {
2383 /* No address specified: default to gateway_ports setting */
2384 if (gateway_ports)
2385 wildcard = 1;
2386 } else if (gateway_ports || is_client) {
2387 if (((datafellows & SSH_OLD_FORWARD_ADDR) &&
2388 strcmp(listen_addr, "0.0.0.0") == 0) ||
2389 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 ||
2390 (!is_client && gateway_ports == 1))
2391 wildcard = 1;
2392 else if (strcmp(listen_addr, "localhost") != 0)
2393 addr = listen_addr;
2394 }
2395
2396 debug3("channel_setup_fwd_listener: type %d wildcard %d addr %s",
2397 type, wildcard, (addr == NULL) ? "NULL" : addr);
2398
2399 /*
2400 * getaddrinfo returns a loopback address if the hostname is
2401 * set to NULL and hints.ai_flags is not AI_PASSIVE
2402 */
2403 memset(&hints, 0, sizeof(hints));
2404 hints.ai_family = IPv4or6;
2405 hints.ai_flags = wildcard ? AI_PASSIVE : 0;
2406 hints.ai_socktype = SOCK_STREAM;
2407 snprintf(strport, sizeof strport, "%d", listen_port);
2408 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) {
2409 if (addr == NULL) {
2410 /* This really shouldn't happen */
2411 packet_disconnect("getaddrinfo: fatal error: %s",
2412 gai_strerror(r));
2413 } else {
2414 error("channel_setup_fwd_listener: "
2415 "getaddrinfo(%.64s): %s", addr, gai_strerror(r));
2416 }
2417 return 0;
2418 }
2419
2420 for (ai = aitop; ai; ai = ai->ai_next) {
2421 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2422 continue;
2423 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2424 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2425 error("channel_setup_fwd_listener: getnameinfo failed");
2426 continue;
2427 }
2428 /* Create a port to listen for the host. */
2429 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2430 if (sock < 0) {
2431 /* this is no error since kernel may not support ipv6 */
2432 verbose("socket: %.100s", strerror(errno));
2433 continue;
2434 }
2435
2436 channel_set_reuseaddr(sock);
2437
2438 debug("Local forwarding listening on %s port %s.", ntop, strport);
2439
2440 /* Bind the socket to the address. */
2441 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2442 /* address can be in use ipv6 address is already bound */
2443 if (!ai->ai_next)
2444 error("bind: %.100s", strerror(errno));
2445 else
2446 verbose("bind: %.100s", strerror(errno));
2447
2448 close(sock);
2449 continue;
2450 }
2451 /* Start listening for connections on the socket. */
2452 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2453 error("listen: %.100s", strerror(errno));
2454 close(sock);
2455 continue;
2456 }
2457 /* Allocate a channel number for the socket. */
2458 c = channel_new("port listener", type, sock, sock, -1,
2459 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2460 0, "port listener", 1);
2461 strlcpy(c->path, host, sizeof(c->path));
2462 c->host_port = port_to_connect;
2463 c->listening_port = listen_port;
2464 success = 1;
2465 }
2466 if (success == 0)
2467 error("channel_setup_fwd_listener: cannot listen to port: %d",
2468 listen_port);
2469 freeaddrinfo(aitop);
2470 return success;
2471 }
2472
2473 int
2474 channel_cancel_rport_listener(const char *host, u_short port)
2475 {
2476 u_int i;
2477 int found = 0;
2478
2479 for (i = 0; i < channels_alloc; i++) {
2480 Channel *c = channels[i];
2481
2482 if (c != NULL && c->type == SSH_CHANNEL_RPORT_LISTENER &&
2483 strncmp(c->path, host, sizeof(c->path)) == 0 &&
2484 c->listening_port == port) {
2485 debug2("%s: close channel %d", __func__, i);
2486 channel_free(c);
2487 found = 1;
2488 }
2489 }
2490
2491 return (found);
2492 }
2493
2494 /* protocol local port fwd, used by ssh (and sshd in v1) */
2495 int
2496 channel_setup_local_fwd_listener(const char *listen_host, u_short listen_port,
2497 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2498 {
2499 return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER,
2500 listen_host, listen_port, host_to_connect, port_to_connect,
2501 gateway_ports);
2502 }
2503
2504 /* protocol v2 remote port fwd, used by sshd */
2505 int
2506 channel_setup_remote_fwd_listener(const char *listen_address,
2507 u_short listen_port, int gateway_ports)
2508 {
2509 return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER,
2510 listen_address, listen_port, NULL, 0, gateway_ports);
2511 }
2512
2513 /*
2514 * Initiate forwarding of connections to port "port" on remote host through
2515 * the secure channel to host:port from local side.
2516 */
2517
2518 int
2519 channel_request_remote_forwarding(const char *listen_host, u_short listen_port,
2520 const char *host_to_connect, u_short port_to_connect)
2521 {
2522 int type, success = 0;
2523
2524 /* Record locally that connection to this host/port is permitted. */
2525 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2526 fatal("channel_request_remote_forwarding: too many forwards");
2527
2528 /* Send the forward request to the remote side. */
2529 if (compat20) {
2530 const char *address_to_bind;
2531 if (listen_host == NULL) {
2532 if (datafellows & SSH_BUG_RFWD_ADDR)
2533 address_to_bind = "127.0.0.1";
2534 else
2535 address_to_bind = "localhost";
2536 } else if (*listen_host == '\0' ||
2537 strcmp(listen_host, "*") == 0) {
2538 if (datafellows & SSH_BUG_RFWD_ADDR)
2539 address_to_bind = "0.0.0.0";
2540 else
2541 address_to_bind = "";
2542 } else
2543 address_to_bind = listen_host;
2544
2545 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2546 packet_put_cstring("tcpip-forward");
2547 packet_put_char(1); /* boolean: want reply */
2548 packet_put_cstring(address_to_bind);
2549 packet_put_int(listen_port);
2550 packet_send();
2551 packet_write_wait();
2552 /* Assume that server accepts the request */
2553 success = 1;
2554 } else {
2555 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2556 packet_put_int(listen_port);
2557 packet_put_cstring(host_to_connect);
2558 packet_put_int(port_to_connect);
2559 packet_send();
2560 packet_write_wait();
2561
2562 /* Wait for response from the remote side. */
2563 type = packet_read();
2564 switch (type) {
2565 case SSH_SMSG_SUCCESS:
2566 success = 1;
2567 break;
2568 case SSH_SMSG_FAILURE:
2569 break;
2570 default:
2571 /* Unknown packet */
2572 packet_disconnect("Protocol error for port forward request:"
2573 "received packet type %d.", type);
2574 }
2575 }
2576 if (success) {
2577 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2578 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2579 permitted_opens[num_permitted_opens].listen_port = listen_port;
2580 num_permitted_opens++;
2581 }
2582 return (success ? 0 : -1);
2583 }
2584
2585 /*
2586 * Request cancellation of remote forwarding of connection host:port from
2587 * local side.
2588 */
2589 void
2590 channel_request_rforward_cancel(const char *host, u_short port)
2591 {
2592 int i;
2593
2594 if (!compat20)
2595 return;
2596
2597 for (i = 0; i < num_permitted_opens; i++) {
2598 if (permitted_opens[i].host_to_connect != NULL &&
2599 permitted_opens[i].listen_port == port)
2600 break;
2601 }
2602 if (i >= num_permitted_opens) {
2603 debug("%s: requested forward not found", __func__);
2604 return;
2605 }
2606 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2607 packet_put_cstring("cancel-tcpip-forward");
2608 packet_put_char(0);
2609 packet_put_cstring(host == NULL ? "" : host);
2610 packet_put_int(port);
2611 packet_send();
2612
2613 permitted_opens[i].listen_port = 0;
2614 permitted_opens[i].port_to_connect = 0;
2615 xfree(permitted_opens[i].host_to_connect);
2616 permitted_opens[i].host_to_connect = NULL;
2617 }
2618
2619 /*
2620 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
2621 * listening for the port, and sends back a success reply (or disconnect
2622 * message if there was an error).
2623 */
2624 int
2625 channel_input_port_forward_request(int is_root, int gateway_ports)
2626 {
2627 u_short port, host_port;
2628 int success = 0;
2629 char *hostname;
2630
2631 /* Get arguments from the packet. */
2632 port = packet_get_int();
2633 hostname = packet_get_string(NULL);
2634 host_port = packet_get_int();
2635
2636 #ifndef HAVE_CYGWIN
2637 /*
2638 * Check that an unprivileged user is not trying to forward a
2639 * privileged port.
2640 */
2641 if (port < IPPORT_RESERVED && !is_root)
2642 packet_disconnect(
2643 "Requested forwarding of port %d but user is not root.",
2644 port);
2645 if (host_port == 0)
2646 packet_disconnect("Dynamic forwarding denied.");
2647 #endif
2648
2649 /* Initiate forwarding */
2650 success = channel_setup_local_fwd_listener(NULL, port, hostname,
2651 host_port, gateway_ports);
2652
2653 /* Free the argument string. */
2654 xfree(hostname);
2655
2656 return (success ? 0 : -1);
2657 }
2658
2659 /*
2660 * Permits opening to any host/port if permitted_opens[] is empty. This is
2661 * usually called by the server, because the user could connect to any port
2662 * anyway, and the server has no way to know but to trust the client anyway.
2663 */
2664 void
2665 channel_permit_all_opens(void)
2666 {
2667 if (num_permitted_opens == 0)
2668 all_opens_permitted = 1;
2669 }
2670
2671 void
2672 channel_add_permitted_opens(char *host, int port)
2673 {
2674 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2675 fatal("channel_add_permitted_opens: too many forwards");
2676 debug("allow port forwarding to host %s port %d", host, port);
2677
2678 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
2679 permitted_opens[num_permitted_opens].port_to_connect = port;
2680 num_permitted_opens++;
2681
2682 all_opens_permitted = 0;
2683 }
2684
2685 int
2686 channel_add_adm_permitted_opens(char *host, int port)
2687 {
2688 if (num_adm_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2689 fatal("channel_add_adm_permitted_opens: too many forwards");
2690 debug("config allows port forwarding to host %s port %d", host, port);
2691
2692 permitted_adm_opens[num_adm_permitted_opens].host_to_connect
2693 = xstrdup(host);
2694 permitted_adm_opens[num_adm_permitted_opens].port_to_connect = port;
2695 return ++num_adm_permitted_opens;
2696 }
2697
2698 void
2699 channel_clear_permitted_opens(void)
2700 {
2701 int i;
2702
2703 for (i = 0; i < num_permitted_opens; i++)
2704 if (permitted_opens[i].host_to_connect != NULL)
2705 xfree(permitted_opens[i].host_to_connect);
2706 num_permitted_opens = 0;
2707 }
2708
2709 void
2710 channel_clear_adm_permitted_opens(void)
2711 {
2712 int i;
2713
2714 for (i = 0; i < num_adm_permitted_opens; i++)
2715 if (permitted_adm_opens[i].host_to_connect != NULL)
2716 xfree(permitted_adm_opens[i].host_to_connect);
2717 num_adm_permitted_opens = 0;
2718 }
2719
2720 /* return socket to remote host, port */
2721 static int
2722 connect_to(const char *host, u_short port)
2723 {
2724 struct addrinfo hints, *ai, *aitop;
2725 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2726 int gaierr;
2727 int sock = -1;
2728
2729 memset(&hints, 0, sizeof(hints));
2730 hints.ai_family = IPv4or6;
2731 hints.ai_socktype = SOCK_STREAM;
2732 snprintf(strport, sizeof strport, "%d", port);
2733 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
2734 error("connect_to %.100s: unknown host (%s)", host,
2735 gai_strerror(gaierr));
2736 return -1;
2737 }
2738 for (ai = aitop; ai; ai = ai->ai_next) {
2739 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2740 continue;
2741 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2742 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2743 error("connect_to: getnameinfo failed");
2744 continue;
2745 }
2746 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2747 if (sock < 0) {
2748 if (ai->ai_next == NULL)
2749 error("socket: %.100s", strerror(errno));
2750 else
2751 verbose("socket: %.100s", strerror(errno));
2752 continue;
2753 }
2754 if (set_nonblock(sock) == -1)
2755 fatal("%s: set_nonblock(%d)", __func__, sock);
2756 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 &&
2757 errno != EINPROGRESS) {
2758 error("connect_to %.100s port %s: %.100s", ntop, strport,
2759 strerror(errno));
2760 close(sock);
2761 continue; /* fail -- try next */
2762 }
2763 break; /* success */
2764
2765 }
2766 freeaddrinfo(aitop);
2767 if (!ai) {
2768 error("connect_to %.100s port %d: failed.", host, port);
2769 return -1;
2770 }
2771 /* success */
2772 set_nodelay(sock);
2773 return sock;
2774 }
2775
2776 int
2777 channel_connect_by_listen_address(u_short listen_port)
2778 {
2779 int i;
2780
2781 for (i = 0; i < num_permitted_opens; i++)
2782 if (permitted_opens[i].host_to_connect != NULL &&
2783 permitted_opens[i].listen_port == listen_port)
2784 return connect_to(
2785 permitted_opens[i].host_to_connect,
2786 permitted_opens[i].port_to_connect);
2787 error("WARNING: Server requests forwarding for unknown listen_port %d",
2788 listen_port);
2789 return -1;
2790 }
2791
2792 /* Check if connecting to that port is permitted and connect. */
2793 int
2794 channel_connect_to(const char *host, u_short port)
2795 {
2796 int i, permit, permit_adm = 1;
2797
2798 permit = all_opens_permitted;
2799 if (!permit) {
2800 for (i = 0; i < num_permitted_opens; i++)
2801 if (permitted_opens[i].host_to_connect != NULL &&
2802 permitted_opens[i].port_to_connect == port &&
2803 strcmp(permitted_opens[i].host_to_connect, host) == 0)
2804 permit = 1;
2805 }
2806
2807 if (num_adm_permitted_opens > 0) {
2808 permit_adm = 0;
2809 for (i = 0; i < num_adm_permitted_opens; i++)
2810 if (permitted_adm_opens[i].host_to_connect != NULL &&
2811 permitted_adm_opens[i].port_to_connect == port &&
2812 strcmp(permitted_adm_opens[i].host_to_connect, host)
2813 == 0)
2814 permit_adm = 1;
2815 }
2816
2817 if (!permit || !permit_adm) {
2818 logit("Received request to connect to host %.100s port %d, "
2819 "but the request was denied.", host, port);
2820 return -1;
2821 }
2822 return connect_to(host, port);
2823 }
2824
2825 void
2826 channel_send_window_changes(void)
2827 {
2828 u_int i;
2829 struct winsize ws;
2830
2831 for (i = 0; i < channels_alloc; i++) {
2832 if (channels[i] == NULL || !channels[i]->client_tty ||
2833 channels[i]->type != SSH_CHANNEL_OPEN)
2834 continue;
2835 if (ioctl(channels[i]->rfd, TIOCGWINSZ, &ws) < 0)
2836 continue;
2837 channel_request_start(i, "window-change", 0);
2838 packet_put_int((u_int)ws.ws_col);
2839 packet_put_int((u_int)ws.ws_row);
2840 packet_put_int((u_int)ws.ws_xpixel);
2841 packet_put_int((u_int)ws.ws_ypixel);
2842 packet_send();
2843 }
2844 }
2845
2846 /* -- X11 forwarding */
2847
2848 /*
2849 * Creates an internet domain socket for listening for X11 connections.
2850 * Returns 0 and a suitable display number for the DISPLAY variable
2851 * stored in display_numberp , or -1 if an error occurs.
2852 */
2853 int
2854 x11_create_display_inet(int x11_display_offset, int x11_use_localhost,
2855 int single_connection, u_int *display_numberp, int **chanids)
2856 {
2857 Channel *nc = NULL;
2858 int display_number, sock;
2859 u_short port;
2860 struct addrinfo hints, *ai, *aitop;
2861 char strport[NI_MAXSERV];
2862 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
2863
2864 if (chanids == NULL)
2865 return -1;
2866
2867 for (display_number = x11_display_offset;
2868 display_number < MAX_DISPLAYS;
2869 display_number++) {
2870 port = 6000 + display_number;
2871 memset(&hints, 0, sizeof(hints));
2872 hints.ai_family = IPv4or6;
2873 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE;
2874 hints.ai_socktype = SOCK_STREAM;
2875 snprintf(strport, sizeof strport, "%d", port);
2876 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
2877 error("getaddrinfo: %.100s", gai_strerror(gaierr));
2878 return -1;
2879 }
2880 for (ai = aitop; ai; ai = ai->ai_next) {
2881 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2882 continue;
2883 sock = socket(ai->ai_family, ai->ai_socktype,
2884 ai->ai_protocol);
2885 if (sock < 0) {
2886 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
2887 error("socket: %.100s", strerror(errno));
2888 freeaddrinfo(aitop);
2889 return -1;
2890 } else {
2891 debug("x11_create_display_inet: Socket family %d not supported",
2892 ai->ai_family);
2893 continue;
2894 }
2895 }
2896 #ifdef IPV6_V6ONLY
2897 if (ai->ai_family == AF_INET6) {
2898 int on = 1;
2899 if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) < 0)
2900 error("setsockopt IPV6_V6ONLY: %.100s", strerror(errno));
2901 }
2902 #endif
2903 channel_set_reuseaddr(sock);
2904 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2905 debug2("bind port %d: %.100s", port, strerror(errno));
2906 close(sock);
2907
2908 if (ai->ai_next)
2909 continue;
2910
2911 for (n = 0; n < num_socks; n++) {
2912 close(socks[n]);
2913 }
2914 num_socks = 0;
2915 break;
2916 }
2917 socks[num_socks++] = sock;
2918 #ifndef DONT_TRY_OTHER_AF
2919 if (num_socks == NUM_SOCKS)
2920 break;
2921 #else
2922 if (x11_use_localhost) {
2923 if (num_socks == NUM_SOCKS)
2924 break;
2925 } else {
2926 break;
2927 }
2928 #endif
2929 }
2930 freeaddrinfo(aitop);
2931 if (num_socks > 0)
2932 break;
2933 }
2934 if (display_number >= MAX_DISPLAYS) {
2935 error("Failed to allocate internet-domain X11 display socket.");
2936 return -1;
2937 }
2938 /* Start listening for connections on the socket. */
2939 for (n = 0; n < num_socks; n++) {
2940 sock = socks[n];
2941 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2942 error("listen: %.100s", strerror(errno));
2943 close(sock);
2944 return -1;
2945 }
2946 }
2947
2948 /* Allocate a channel for each socket. */
2949 *chanids = xcalloc(num_socks + 1, sizeof(**chanids));
2950 for (n = 0; n < num_socks; n++) {
2951 sock = socks[n];
2952 nc = channel_new("x11 listener",
2953 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
2954 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2955 0, "X11 inet listener", 1);
2956 nc->single_connection = single_connection;
2957 (*chanids)[n] = nc->self;
2958 }
2959 (*chanids)[n] = -1;
2960
2961 /* Return the display number for the DISPLAY environment variable. */
2962 *display_numberp = display_number;
2963 return (0);
2964 }
2965
2966 static int
2967 connect_local_xsocket(u_int dnr)
2968 {
2969 int sock;
2970 struct sockaddr_un addr;
2971
2972 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2973 if (sock < 0)
2974 error("socket: %.100s", strerror(errno));
2975 memset(&addr, 0, sizeof(addr));
2976 addr.sun_family = AF_UNIX;
2977 snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr);
2978 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0)
2979 return sock;
2980 close(sock);
2981 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
2982 return -1;
2983 }
2984
2985 int
2986 x11_connect_display(void)
2987 {
2988 u_int display_number;
2989 const char *display;
2990 char buf[1024], *cp;
2991 struct addrinfo hints, *ai, *aitop;
2992 char strport[NI_MAXSERV];
2993 int gaierr, sock = 0;
2994
2995 /* Try to open a socket for the local X server. */
2996 display = getenv("DISPLAY");
2997 if (!display) {
2998 error("DISPLAY not set.");
2999 return -1;
3000 }
3001 /*
3002 * Now we decode the value of the DISPLAY variable and make a
3003 * connection to the real X server.
3004 */
3005
3006 /*
3007 * Check if it is a unix domain socket. Unix domain displays are in
3008 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
3009 */
3010 if (strncmp(display, "unix:", 5) == 0 ||
3011 display[0] == ':') {
3012 /* Connect to the unix domain socket. */
3013 if (sscanf(strrchr(display, ':') + 1, "%u", &display_number) != 1) {
3014 error("Could not parse display number from DISPLAY: %.100s",
3015 display);
3016 return -1;
3017 }
3018 /* Create a socket. */
3019 sock = connect_local_xsocket(display_number);
3020 if (sock < 0)
3021 return -1;
3022
3023 /* OK, we now have a connection to the display. */
3024 return sock;
3025 }
3026 /*
3027 * Connect to an inet socket. The DISPLAY value is supposedly
3028 * hostname:d[.s], where hostname may also be numeric IP address.
3029 */
3030 strlcpy(buf, display, sizeof(buf));
3031 cp = strchr(buf, ':');
3032 if (!cp) {
3033 error("Could not find ':' in DISPLAY: %.100s", display);
3034 return -1;
3035 }
3036 *cp = 0;
3037 /* buf now contains the host name. But first we parse the display number. */
3038 if (sscanf(cp + 1, "%u", &display_number) != 1) {
3039 error("Could not parse display number from DISPLAY: %.100s",
3040 display);
3041 return -1;
3042 }
3043
3044 /* Look up the host address */
3045 memset(&hints, 0, sizeof(hints));
3046 hints.ai_family = IPv4or6;
3047 hints.ai_socktype = SOCK_STREAM;
3048 snprintf(strport, sizeof strport, "%u", 6000 + display_number);
3049 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
3050 error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr));
3051 return -1;
3052 }
3053 for (ai = aitop; ai; ai = ai->ai_next) {
3054 /* Create a socket. */
3055 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
3056 if (sock < 0) {
3057 debug2("socket: %.100s", strerror(errno));
3058 continue;
3059 }
3060 /* Connect it to the display. */
3061 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
3062 debug2("connect %.100s port %u: %.100s", buf,
3063 6000 + display_number, strerror(errno));
3064 close(sock);
3065 continue;
3066 }
3067 /* Success */
3068 break;
3069 }
3070 freeaddrinfo(aitop);
3071 if (!ai) {
3072 error("connect %.100s port %u: %.100s", buf, 6000 + display_number,
3073 strerror(errno));
3074 return -1;
3075 }
3076 set_nodelay(sock);
3077 return sock;
3078 }
3079
3080 /*
3081 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
3082 * the remote channel number. We should do whatever we want, and respond
3083 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
3084 */
3085
3086 /* ARGSUSED */
3087 void
3088 x11_input_open(int type, u_int32_t seq, void *ctxt)
3089 {
3090 Channel *c = NULL;
3091 int remote_id, sock = 0;
3092 char *remote_host;
3093
3094 debug("Received X11 open request.");
3095
3096 remote_id = packet_get_int();
3097
3098 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
3099 remote_host = packet_get_string(NULL);
3100 } else {
3101 remote_host = xstrdup("unknown (remote did not supply name)");
3102 }
3103 packet_check_eom();
3104
3105 /* Obtain a connection to the real X display. */
3106 sock = x11_connect_display();
3107 if (sock != -1) {
3108 /* Allocate a channel for this connection. */
3109 c = channel_new("connected x11 socket",
3110 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
3111 remote_host, 1);
3112 c->remote_id = remote_id;
3113 c->force_drain = 1;
3114 }
3115 xfree(remote_host);
3116 if (c == NULL) {
3117 /* Send refusal to the remote host. */
3118 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3119 packet_put_int(remote_id);
3120 } else {
3121 /* Send a confirmation to the remote host. */
3122 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
3123 packet_put_int(remote_id);
3124 packet_put_int(c->self);
3125 }
3126 packet_send();
3127 }
3128
3129 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
3130 /* ARGSUSED */
3131 void
3132 deny_input_open(int type, u_int32_t seq, void *ctxt)
3133 {
3134 int rchan = packet_get_int();
3135
3136 switch (type) {
3137 case SSH_SMSG_AGENT_OPEN:
3138 error("Warning: ssh server tried agent forwarding.");
3139 break;
3140 case SSH_SMSG_X11_OPEN:
3141 error("Warning: ssh server tried X11 forwarding.");
3142 break;
3143 default:
3144 error("deny_input_open: type %d", type);
3145 break;
3146 }
3147 error("Warning: this is probably a break-in attempt by a malicious server.");
3148 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3149 packet_put_int(rchan);
3150 packet_send();
3151 }
3152
3153 /*
3154 * Requests forwarding of X11 connections, generates fake authentication
3155 * data, and enables authentication spoofing.
3156 * This should be called in the client only.
3157 */
3158 void
3159 x11_request_forwarding_with_spoofing(int client_session_id, const char *disp,
3160 const char *proto, const char *data)
3161 {
3162 u_int data_len = (u_int) strlen(data) / 2;
3163 u_int i, value;
3164 char *new_data;
3165 int screen_number;
3166 const char *cp;
3167 u_int32_t rnd = 0;
3168
3169 if (x11_saved_display == NULL)
3170 x11_saved_display = xstrdup(disp);
3171 else if (strcmp(disp, x11_saved_display) != 0) {
3172 error("x11_request_forwarding_with_spoofing: different "
3173 "$DISPLAY already forwarded");
3174 return;
3175 }
3176
3177 cp = strchr(disp, ':');
3178 if (cp)
3179 cp = strchr(cp, '.');
3180 if (cp)
3181 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL);
3182 else
3183 screen_number = 0;
3184
3185 if (x11_saved_proto == NULL) {
3186 /* Save protocol name. */
3187 x11_saved_proto = xstrdup(proto);
3188 /*
3189 * Extract real authentication data and generate fake data
3190 * of the same length.
3191 */
3192 x11_saved_data = xmalloc(data_len);
3193 x11_fake_data = xmalloc(data_len);
3194 for (i = 0; i < data_len; i++) {
3195 if (sscanf(data + 2 * i, "%2x", &value) != 1)
3196 fatal("x11_request_forwarding: bad "
3197 "authentication data: %.100s", data);
3198 if (i % 4 == 0)
3199 rnd = arc4random();
3200 x11_saved_data[i] = value;
3201 x11_fake_data[i] = rnd & 0xff;
3202 rnd >>= 8;
3203 }
3204 x11_saved_data_len = data_len;
3205 x11_fake_data_len = data_len;
3206 }
3207
3208 /* Convert the fake data into hex. */
3209 new_data = tohex(x11_fake_data, data_len);
3210
3211 /* Send the request packet. */
3212 if (compat20) {
3213 channel_request_start(client_session_id, "x11-req", 0);
3214 packet_put_char(0); /* XXX bool single connection */
3215 } else {
3216 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
3217 }
3218 packet_put_cstring(proto);
3219 packet_put_cstring(new_data);
3220 packet_put_int(screen_number);
3221 packet_send();
3222 packet_write_wait();
3223 xfree(new_data);
3224 }
3225
3226
3227 /* -- agent forwarding */
3228
3229 /* Sends a message to the server to request authentication fd forwarding. */
3230
3231 void
3232 auth_request_forwarding(void)
3233 {
3234 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
3235 packet_send();
3236 packet_write_wait();
3237 }
DragonFly BSD