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- (djm) [audit-bsm.c] Sprinkle in some headers
[openssh-git.git] / channels.c
blobdfa1e591bf0fbc74437315a0cfd52a382df24676
1 /* $OpenBSD: channels.c,v 1.265 2006/08/03 03:34:41 deraadt 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;
1450
1451 if (c->rfd != -1 &&
1452 FD_ISSET(c->rfd, readset)) {
1453 errno = 0;
1454 len = read(c->rfd, buf, sizeof(buf));
1455 if (len < 0 && (errno == EINTR || errno == EAGAIN))
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 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 || errno == EAGAIN))
1612 return 1;
1613 if (len <= 0) {
1614 debug2("channel %d: closing read-efd %d",
1615 c->self, c->efd);
1616 channel_close_fd(&c->efd);
1617 } else {
1618 buffer_append(&c->extended, buf, len);
1619 }
1620 }
1621 }
1622 return 1;
1623 }
1624
1625 /* ARGSUSED */
1626 static int
1627 channel_handle_ctl(Channel *c, fd_set *readset, fd_set *writeset)
1628 {
1629 char buf[16];
1630 int len;
1631
1632 /* Monitor control fd to detect if the slave client exits */
1633 if (c->ctl_fd != -1 && FD_ISSET(c->ctl_fd, readset)) {
1634 len = read(c->ctl_fd, buf, sizeof(buf));
1635 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1636 return 1;
1637 if (len <= 0) {
1638 debug2("channel %d: ctl read<=0", c->self);
1639 if (c->type != SSH_CHANNEL_OPEN) {
1640 debug2("channel %d: not open", c->self);
1641 chan_mark_dead(c);
1642 return -1;
1643 } else {
1644 chan_read_failed(c);
1645 chan_write_failed(c);
1646 }
1647 return -1;
1648 } else
1649 fatal("%s: unexpected data on ctl fd", __func__);
1650 }
1651 return 1;
1652 }
1653
1654 static int
1655 channel_check_window(Channel *c)
1656 {
1657 if (c->type == SSH_CHANNEL_OPEN &&
1658 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1659 c->local_window < c->local_window_max/2 &&
1660 c->local_consumed > 0) {
1661 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1662 packet_put_int(c->remote_id);
1663 packet_put_int(c->local_consumed);
1664 packet_send();
1665 debug2("channel %d: window %d sent adjust %d",
1666 c->self, c->local_window,
1667 c->local_consumed);
1668 c->local_window += c->local_consumed;
1669 c->local_consumed = 0;
1670 }
1671 return 1;
1672 }
1673
1674 static void
1675 channel_post_open(Channel *c, fd_set *readset, fd_set *writeset)
1676 {
1677 if (c->delayed)
1678 return;
1679 channel_handle_rfd(c, readset, writeset);
1680 channel_handle_wfd(c, readset, writeset);
1681 if (!compat20)
1682 return;
1683 channel_handle_efd(c, readset, writeset);
1684 channel_handle_ctl(c, readset, writeset);
1685 channel_check_window(c);
1686 }
1687
1688 /* ARGSUSED */
1689 static void
1690 channel_post_output_drain_13(Channel *c, fd_set *readset, fd_set *writeset)
1691 {
1692 int len;
1693
1694 /* Send buffered output data to the socket. */
1695 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1696 len = write(c->sock, buffer_ptr(&c->output),
1697 buffer_len(&c->output));
1698 if (len <= 0)
1699 buffer_clear(&c->output);
1700 else
1701 buffer_consume(&c->output, len);
1702 }
1703 }
1704
1705 static void
1706 channel_handler_init_20(void)
1707 {
1708 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1709 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1710 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1711 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
1712 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1713 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1714 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1715 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1716
1717 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1718 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1719 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
1720 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1721 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1722 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1723 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1724 }
1725
1726 static void
1727 channel_handler_init_13(void)
1728 {
1729 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
1730 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
1731 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1732 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1733 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1734 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
1735 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1736 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1737 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1738
1739 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1740 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1741 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1742 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1743 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
1744 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1745 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1746 }
1747
1748 static void
1749 channel_handler_init_15(void)
1750 {
1751 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1752 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1753 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1754 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1755 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1756 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1757 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1758
1759 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1760 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1761 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1762 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1763 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1764 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1765 }
1766
1767 static void
1768 channel_handler_init(void)
1769 {
1770 int i;
1771
1772 for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
1773 channel_pre[i] = NULL;
1774 channel_post[i] = NULL;
1775 }
1776 if (compat20)
1777 channel_handler_init_20();
1778 else if (compat13)
1779 channel_handler_init_13();
1780 else
1781 channel_handler_init_15();
1782 }
1783
1784 /* gc dead channels */
1785 static void
1786 channel_garbage_collect(Channel *c)
1787 {
1788 if (c == NULL)
1789 return;
1790 if (c->detach_user != NULL) {
1791 if (!chan_is_dead(c, c->detach_close))
1792 return;
1793 debug2("channel %d: gc: notify user", c->self);
1794 c->detach_user(c->self, NULL);
1795 /* if we still have a callback */
1796 if (c->detach_user != NULL)
1797 return;
1798 debug2("channel %d: gc: user detached", c->self);
1799 }
1800 if (!chan_is_dead(c, 1))
1801 return;
1802 debug2("channel %d: garbage collecting", c->self);
1803 channel_free(c);
1804 }
1805
1806 static void
1807 channel_handler(chan_fn *ftab[], fd_set *readset, fd_set *writeset)
1808 {
1809 static int did_init = 0;
1810 u_int i;
1811 Channel *c;
1812
1813 if (!did_init) {
1814 channel_handler_init();
1815 did_init = 1;
1816 }
1817 for (i = 0; i < channels_alloc; i++) {
1818 c = channels[i];
1819 if (c == NULL)
1820 continue;
1821 if (ftab[c->type] != NULL)
1822 (*ftab[c->type])(c, readset, writeset);
1823 channel_garbage_collect(c);
1824 }
1825 }
1826
1827 /*
1828 * Allocate/update select bitmasks and add any bits relevant to channels in
1829 * select bitmasks.
1830 */
1831 void
1832 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
1833 u_int *nallocp, int rekeying)
1834 {
1835 u_int n, sz, nfdset;
1836
1837 n = MAX(*maxfdp, channel_max_fd);
1838
1839 nfdset = howmany(n+1, NFDBITS);
1840 /* Explicitly test here, because xrealloc isn't always called */
1841 if (nfdset && SIZE_T_MAX / nfdset < sizeof(fd_mask))
1842 fatal("channel_prepare_select: max_fd (%d) is too large", n);
1843 sz = nfdset * sizeof(fd_mask);
1844
1845 /* perhaps check sz < nalloc/2 and shrink? */
1846 if (*readsetp == NULL || sz > *nallocp) {
1847 *readsetp = xrealloc(*readsetp, nfdset, sizeof(fd_mask));
1848 *writesetp = xrealloc(*writesetp, nfdset, sizeof(fd_mask));
1849 *nallocp = sz;
1850 }
1851 *maxfdp = n;
1852 memset(*readsetp, 0, sz);
1853 memset(*writesetp, 0, sz);
1854
1855 if (!rekeying)
1856 channel_handler(channel_pre, *readsetp, *writesetp);
1857 }
1858
1859 /*
1860 * After select, perform any appropriate operations for channels which have
1861 * events pending.
1862 */
1863 void
1864 channel_after_select(fd_set *readset, fd_set *writeset)
1865 {
1866 channel_handler(channel_post, readset, writeset);
1867 }
1868
1869
1870 /* If there is data to send to the connection, enqueue some of it now. */
1871 void
1872 channel_output_poll(void)
1873 {
1874 Channel *c;
1875 u_int i, len;
1876
1877 for (i = 0; i < channels_alloc; i++) {
1878 c = channels[i];
1879 if (c == NULL)
1880 continue;
1881
1882 /*
1883 * We are only interested in channels that can have buffered
1884 * incoming data.
1885 */
1886 if (compat13) {
1887 if (c->type != SSH_CHANNEL_OPEN &&
1888 c->type != SSH_CHANNEL_INPUT_DRAINING)
1889 continue;
1890 } else {
1891 if (c->type != SSH_CHANNEL_OPEN)
1892 continue;
1893 }
1894 if (compat20 &&
1895 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
1896 /* XXX is this true? */
1897 debug3("channel %d: will not send data after close", c->self);
1898 continue;
1899 }
1900
1901 /* Get the amount of buffered data for this channel. */
1902 if ((c->istate == CHAN_INPUT_OPEN ||
1903 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
1904 (len = buffer_len(&c->input)) > 0) {
1905 if (c->datagram) {
1906 if (len > 0) {
1907 u_char *data;
1908 u_int dlen;
1909
1910 data = buffer_get_string(&c->input,
1911 &dlen);
1912 packet_start(SSH2_MSG_CHANNEL_DATA);
1913 packet_put_int(c->remote_id);
1914 packet_put_string(data, dlen);
1915 packet_send();
1916 c->remote_window -= dlen + 4;
1917 xfree(data);
1918 }
1919 continue;
1920 }
1921 /*
1922 * Send some data for the other side over the secure
1923 * connection.
1924 */
1925 if (compat20) {
1926 if (len > c->remote_window)
1927 len = c->remote_window;
1928 if (len > c->remote_maxpacket)
1929 len = c->remote_maxpacket;
1930 } else {
1931 if (packet_is_interactive()) {
1932 if (len > 1024)
1933 len = 512;
1934 } else {
1935 /* Keep the packets at reasonable size. */
1936 if (len > packet_get_maxsize()/2)
1937 len = packet_get_maxsize()/2;
1938 }
1939 }
1940 if (len > 0) {
1941 packet_start(compat20 ?
1942 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
1943 packet_put_int(c->remote_id);
1944 packet_put_string(buffer_ptr(&c->input), len);
1945 packet_send();
1946 buffer_consume(&c->input, len);
1947 c->remote_window -= len;
1948 }
1949 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1950 if (compat13)
1951 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
1952 /*
1953 * input-buffer is empty and read-socket shutdown:
1954 * tell peer, that we will not send more data: send IEOF.
1955 * hack for extended data: delay EOF if EFD still in use.
1956 */
1957 if (CHANNEL_EFD_INPUT_ACTIVE(c))
1958 debug2("channel %d: ibuf_empty delayed efd %d/(%d)",
1959 c->self, c->efd, buffer_len(&c->extended));
1960 else
1961 chan_ibuf_empty(c);
1962 }
1963 /* Send extended data, i.e. stderr */
1964 if (compat20 &&
1965 !(c->flags & CHAN_EOF_SENT) &&
1966 c->remote_window > 0 &&
1967 (len = buffer_len(&c->extended)) > 0 &&
1968 c->extended_usage == CHAN_EXTENDED_READ) {
1969 debug2("channel %d: rwin %u elen %u euse %d",
1970 c->self, c->remote_window, buffer_len(&c->extended),
1971 c->extended_usage);
1972 if (len > c->remote_window)
1973 len = c->remote_window;
1974 if (len > c->remote_maxpacket)
1975 len = c->remote_maxpacket;
1976 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
1977 packet_put_int(c->remote_id);
1978 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
1979 packet_put_string(buffer_ptr(&c->extended), len);
1980 packet_send();
1981 buffer_consume(&c->extended, len);
1982 c->remote_window -= len;
1983 debug2("channel %d: sent ext data %d", c->self, len);
1984 }
1985 }
1986 }
1987
1988
1989 /* -- protocol input */
1990
1991 /* ARGSUSED */
1992 void
1993 channel_input_data(int type, u_int32_t seq, void *ctxt)
1994 {
1995 int id;
1996 char *data;
1997 u_int data_len;
1998 Channel *c;
1999
2000 /* Get the channel number and verify it. */
2001 id = packet_get_int();
2002 c = channel_lookup(id);
2003 if (c == NULL)
2004 packet_disconnect("Received data for nonexistent channel %d.", id);
2005
2006 /* Ignore any data for non-open channels (might happen on close) */
2007 if (c->type != SSH_CHANNEL_OPEN &&
2008 c->type != SSH_CHANNEL_X11_OPEN)
2009 return;
2010
2011 /* Get the data. */
2012 data = packet_get_string(&data_len);
2013
2014 /*
2015 * Ignore data for protocol > 1.3 if output end is no longer open.
2016 * For protocol 2 the sending side is reducing its window as it sends
2017 * data, so we must 'fake' consumption of the data in order to ensure
2018 * that window updates are sent back. Otherwise the connection might
2019 * deadlock.
2020 */
2021 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) {
2022 if (compat20) {
2023 c->local_window -= data_len;
2024 c->local_consumed += data_len;
2025 }
2026 xfree(data);
2027 return;
2028 }
2029
2030 if (compat20) {
2031 if (data_len > c->local_maxpacket) {
2032 logit("channel %d: rcvd big packet %d, maxpack %d",
2033 c->self, data_len, c->local_maxpacket);
2034 }
2035 if (data_len > c->local_window) {
2036 logit("channel %d: rcvd too much data %d, win %d",
2037 c->self, data_len, c->local_window);
2038 xfree(data);
2039 return;
2040 }
2041 c->local_window -= data_len;
2042 }
2043 packet_check_eom();
2044 if (c->datagram)
2045 buffer_put_string(&c->output, data, data_len);
2046 else
2047 buffer_append(&c->output, data, data_len);
2048 xfree(data);
2049 }
2050
2051 /* ARGSUSED */
2052 void
2053 channel_input_extended_data(int type, u_int32_t seq, void *ctxt)
2054 {
2055 int id;
2056 char *data;
2057 u_int data_len, tcode;
2058 Channel *c;
2059
2060 /* Get the channel number and verify it. */
2061 id = packet_get_int();
2062 c = channel_lookup(id);
2063
2064 if (c == NULL)
2065 packet_disconnect("Received extended_data for bad channel %d.", id);
2066 if (c->type != SSH_CHANNEL_OPEN) {
2067 logit("channel %d: ext data for non open", id);
2068 return;
2069 }
2070 if (c->flags & CHAN_EOF_RCVD) {
2071 if (datafellows & SSH_BUG_EXTEOF)
2072 debug("channel %d: accepting ext data after eof", id);
2073 else
2074 packet_disconnect("Received extended_data after EOF "
2075 "on channel %d.", id);
2076 }
2077 tcode = packet_get_int();
2078 if (c->efd == -1 ||
2079 c->extended_usage != CHAN_EXTENDED_WRITE ||
2080 tcode != SSH2_EXTENDED_DATA_STDERR) {
2081 logit("channel %d: bad ext data", c->self);
2082 return;
2083 }
2084 data = packet_get_string(&data_len);
2085 packet_check_eom();
2086 if (data_len > c->local_window) {
2087 logit("channel %d: rcvd too much extended_data %d, win %d",
2088 c->self, data_len, c->local_window);
2089 xfree(data);
2090 return;
2091 }
2092 debug2("channel %d: rcvd ext data %d", c->self, data_len);
2093 c->local_window -= data_len;
2094 buffer_append(&c->extended, data, data_len);
2095 xfree(data);
2096 }
2097
2098 /* ARGSUSED */
2099 void
2100 channel_input_ieof(int type, u_int32_t seq, void *ctxt)
2101 {
2102 int id;
2103 Channel *c;
2104
2105 id = packet_get_int();
2106 packet_check_eom();
2107 c = channel_lookup(id);
2108 if (c == NULL)
2109 packet_disconnect("Received ieof for nonexistent channel %d.", id);
2110 chan_rcvd_ieof(c);
2111
2112 /* XXX force input close */
2113 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) {
2114 debug("channel %d: FORCE input drain", c->self);
2115 c->istate = CHAN_INPUT_WAIT_DRAIN;
2116 if (buffer_len(&c->input) == 0)
2117 chan_ibuf_empty(c);
2118 }
2119
2120 }
2121
2122 /* ARGSUSED */
2123 void
2124 channel_input_close(int type, u_int32_t seq, void *ctxt)
2125 {
2126 int id;
2127 Channel *c;
2128
2129 id = packet_get_int();
2130 packet_check_eom();
2131 c = channel_lookup(id);
2132 if (c == NULL)
2133 packet_disconnect("Received close for nonexistent channel %d.", id);
2134
2135 /*
2136 * Send a confirmation that we have closed the channel and no more
2137 * data is coming for it.
2138 */
2139 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
2140 packet_put_int(c->remote_id);
2141 packet_send();
2142
2143 /*
2144 * If the channel is in closed state, we have sent a close request,
2145 * and the other side will eventually respond with a confirmation.
2146 * Thus, we cannot free the channel here, because then there would be
2147 * no-one to receive the confirmation. The channel gets freed when
2148 * the confirmation arrives.
2149 */
2150 if (c->type != SSH_CHANNEL_CLOSED) {
2151 /*
2152 * Not a closed channel - mark it as draining, which will
2153 * cause it to be freed later.
2154 */
2155 buffer_clear(&c->input);
2156 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
2157 }
2158 }
2159
2160 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
2161 /* ARGSUSED */
2162 void
2163 channel_input_oclose(int type, u_int32_t seq, void *ctxt)
2164 {
2165 int id = packet_get_int();
2166 Channel *c = channel_lookup(id);
2167
2168 packet_check_eom();
2169 if (c == NULL)
2170 packet_disconnect("Received oclose for nonexistent channel %d.", id);
2171 chan_rcvd_oclose(c);
2172 }
2173
2174 /* ARGSUSED */
2175 void
2176 channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt)
2177 {
2178 int id = packet_get_int();
2179 Channel *c = channel_lookup(id);
2180
2181 packet_check_eom();
2182 if (c == NULL)
2183 packet_disconnect("Received close confirmation for "
2184 "out-of-range channel %d.", id);
2185 if (c->type != SSH_CHANNEL_CLOSED)
2186 packet_disconnect("Received close confirmation for "
2187 "non-closed channel %d (type %d).", id, c->type);
2188 channel_free(c);
2189 }
2190
2191 /* ARGSUSED */
2192 void
2193 channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt)
2194 {
2195 int id, remote_id;
2196 Channel *c;
2197
2198 id = packet_get_int();
2199 c = channel_lookup(id);
2200
2201 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2202 packet_disconnect("Received open confirmation for "
2203 "non-opening channel %d.", id);
2204 remote_id = packet_get_int();
2205 /* Record the remote channel number and mark that the channel is now open. */
2206 c->remote_id = remote_id;
2207 c->type = SSH_CHANNEL_OPEN;
2208
2209 if (compat20) {
2210 c->remote_window = packet_get_int();
2211 c->remote_maxpacket = packet_get_int();
2212 if (c->confirm) {
2213 debug2("callback start");
2214 c->confirm(c->self, c->confirm_ctx);
2215 debug2("callback done");
2216 }
2217 debug2("channel %d: open confirm rwindow %u rmax %u", c->self,
2218 c->remote_window, c->remote_maxpacket);
2219 }
2220 packet_check_eom();
2221 }
2222
2223 static char *
2224 reason2txt(int reason)
2225 {
2226 switch (reason) {
2227 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
2228 return "administratively prohibited";
2229 case SSH2_OPEN_CONNECT_FAILED:
2230 return "connect failed";
2231 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
2232 return "unknown channel type";
2233 case SSH2_OPEN_RESOURCE_SHORTAGE:
2234 return "resource shortage";
2235 }
2236 return "unknown reason";
2237 }
2238
2239 /* ARGSUSED */
2240 void
2241 channel_input_open_failure(int type, u_int32_t seq, void *ctxt)
2242 {
2243 int id, reason;
2244 char *msg = NULL, *lang = NULL;
2245 Channel *c;
2246
2247 id = packet_get_int();
2248 c = channel_lookup(id);
2249
2250 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2251 packet_disconnect("Received open failure for "
2252 "non-opening channel %d.", id);
2253 if (compat20) {
2254 reason = packet_get_int();
2255 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
2256 msg = packet_get_string(NULL);
2257 lang = packet_get_string(NULL);
2258 }
2259 logit("channel %d: open failed: %s%s%s", id,
2260 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
2261 if (msg != NULL)
2262 xfree(msg);
2263 if (lang != NULL)
2264 xfree(lang);
2265 }
2266 packet_check_eom();
2267 /* Free the channel. This will also close the socket. */
2268 channel_free(c);
2269 }
2270
2271 /* ARGSUSED */
2272 void
2273 channel_input_window_adjust(int type, u_int32_t seq, void *ctxt)
2274 {
2275 Channel *c;
2276 int id;
2277 u_int adjust;
2278
2279 if (!compat20)
2280 return;
2281
2282 /* Get the channel number and verify it. */
2283 id = packet_get_int();
2284 c = channel_lookup(id);
2285
2286 if (c == NULL) {
2287 logit("Received window adjust for non-open channel %d.", id);
2288 return;
2289 }
2290 adjust = packet_get_int();
2291 packet_check_eom();
2292 debug2("channel %d: rcvd adjust %u", id, adjust);
2293 c->remote_window += adjust;
2294 }
2295
2296 /* ARGSUSED */
2297 void
2298 channel_input_port_open(int type, u_int32_t seq, void *ctxt)
2299 {
2300 Channel *c = NULL;
2301 u_short host_port;
2302 char *host, *originator_string;
2303 int remote_id, sock = -1;
2304
2305 remote_id = packet_get_int();
2306 host = packet_get_string(NULL);
2307 host_port = packet_get_int();
2308
2309 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2310 originator_string = packet_get_string(NULL);
2311 } else {
2312 originator_string = xstrdup("unknown (remote did not supply name)");
2313 }
2314 packet_check_eom();
2315 sock = channel_connect_to(host, host_port);
2316 if (sock != -1) {
2317 c = channel_new("connected socket",
2318 SSH_CHANNEL_CONNECTING, sock, sock, -1, 0, 0, 0,
2319 originator_string, 1);
2320 c->remote_id = remote_id;
2321 }
2322 xfree(originator_string);
2323 if (c == NULL) {
2324 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2325 packet_put_int(remote_id);
2326 packet_send();
2327 }
2328 xfree(host);
2329 }
2330
2331
2332 /* -- tcp forwarding */
2333
2334 void
2335 channel_set_af(int af)
2336 {
2337 IPv4or6 = af;
2338 }
2339
2340 static int
2341 channel_setup_fwd_listener(int type, const char *listen_addr, u_short listen_port,
2342 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2343 {
2344 Channel *c;
2345 int sock, r, success = 0, wildcard = 0, is_client;
2346 struct addrinfo hints, *ai, *aitop;
2347 const char *host, *addr;
2348 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2349
2350 host = (type == SSH_CHANNEL_RPORT_LISTENER) ?
2351 listen_addr : host_to_connect;
2352 is_client = (type == SSH_CHANNEL_PORT_LISTENER);
2353
2354 if (host == NULL) {
2355 error("No forward host name.");
2356 return 0;
2357 }
2358 if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) {
2359 error("Forward host name too long.");
2360 return 0;
2361 }
2362
2363 /*
2364 * Determine whether or not a port forward listens to loopback,
2365 * specified address or wildcard. On the client, a specified bind
2366 * address will always override gateway_ports. On the server, a
2367 * gateway_ports of 1 (``yes'') will override the client's
2368 * specification and force a wildcard bind, whereas a value of 2
2369 * (``clientspecified'') will bind to whatever address the client
2370 * asked for.
2371 *
2372 * Special-case listen_addrs are:
2373 *
2374 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR
2375 * "" (empty string), "*" -> wildcard v4/v6
2376 * "localhost" -> loopback v4/v6
2377 */
2378 addr = NULL;
2379 if (listen_addr == NULL) {
2380 /* No address specified: default to gateway_ports setting */
2381 if (gateway_ports)
2382 wildcard = 1;
2383 } else if (gateway_ports || is_client) {
2384 if (((datafellows & SSH_OLD_FORWARD_ADDR) &&
2385 strcmp(listen_addr, "0.0.0.0") == 0) ||
2386 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 ||
2387 (!is_client && gateway_ports == 1))
2388 wildcard = 1;
2389 else if (strcmp(listen_addr, "localhost") != 0)
2390 addr = listen_addr;
2391 }
2392
2393 debug3("channel_setup_fwd_listener: type %d wildcard %d addr %s",
2394 type, wildcard, (addr == NULL) ? "NULL" : addr);
2395
2396 /*
2397 * getaddrinfo returns a loopback address if the hostname is
2398 * set to NULL and hints.ai_flags is not AI_PASSIVE
2399 */
2400 memset(&hints, 0, sizeof(hints));
2401 hints.ai_family = IPv4or6;
2402 hints.ai_flags = wildcard ? AI_PASSIVE : 0;
2403 hints.ai_socktype = SOCK_STREAM;
2404 snprintf(strport, sizeof strport, "%d", listen_port);
2405 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) {
2406 if (addr == NULL) {
2407 /* This really shouldn't happen */
2408 packet_disconnect("getaddrinfo: fatal error: %s",
2409 gai_strerror(r));
2410 } else {
2411 error("channel_setup_fwd_listener: "
2412 "getaddrinfo(%.64s): %s", addr, gai_strerror(r));
2413 }
2414 return 0;
2415 }
2416
2417 for (ai = aitop; ai; ai = ai->ai_next) {
2418 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2419 continue;
2420 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2421 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2422 error("channel_setup_fwd_listener: getnameinfo failed");
2423 continue;
2424 }
2425 /* Create a port to listen for the host. */
2426 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2427 if (sock < 0) {
2428 /* this is no error since kernel may not support ipv6 */
2429 verbose("socket: %.100s", strerror(errno));
2430 continue;
2431 }
2432
2433 channel_set_reuseaddr(sock);
2434
2435 debug("Local forwarding listening on %s port %s.", ntop, strport);
2436
2437 /* Bind the socket to the address. */
2438 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2439 /* address can be in use ipv6 address is already bound */
2440 if (!ai->ai_next)
2441 error("bind: %.100s", strerror(errno));
2442 else
2443 verbose("bind: %.100s", strerror(errno));
2444
2445 close(sock);
2446 continue;
2447 }
2448 /* Start listening for connections on the socket. */
2449 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2450 error("listen: %.100s", strerror(errno));
2451 close(sock);
2452 continue;
2453 }
2454 /* Allocate a channel number for the socket. */
2455 c = channel_new("port listener", type, sock, sock, -1,
2456 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2457 0, "port listener", 1);
2458 strlcpy(c->path, host, sizeof(c->path));
2459 c->host_port = port_to_connect;
2460 c->listening_port = listen_port;
2461 success = 1;
2462 }
2463 if (success == 0)
2464 error("channel_setup_fwd_listener: cannot listen to port: %d",
2465 listen_port);
2466 freeaddrinfo(aitop);
2467 return success;
2468 }
2469
2470 int
2471 channel_cancel_rport_listener(const char *host, u_short port)
2472 {
2473 u_int i;
2474 int found = 0;
2475
2476 for (i = 0; i < channels_alloc; i++) {
2477 Channel *c = channels[i];
2478
2479 if (c != NULL && c->type == SSH_CHANNEL_RPORT_LISTENER &&
2480 strncmp(c->path, host, sizeof(c->path)) == 0 &&
2481 c->listening_port == port) {
2482 debug2("%s: close channel %d", __func__, i);
2483 channel_free(c);
2484 found = 1;
2485 }
2486 }
2487
2488 return (found);
2489 }
2490
2491 /* protocol local port fwd, used by ssh (and sshd in v1) */
2492 int
2493 channel_setup_local_fwd_listener(const char *listen_host, u_short listen_port,
2494 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2495 {
2496 return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER,
2497 listen_host, listen_port, host_to_connect, port_to_connect,
2498 gateway_ports);
2499 }
2500
2501 /* protocol v2 remote port fwd, used by sshd */
2502 int
2503 channel_setup_remote_fwd_listener(const char *listen_address,
2504 u_short listen_port, int gateway_ports)
2505 {
2506 return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER,
2507 listen_address, listen_port, NULL, 0, gateway_ports);
2508 }
2509
2510 /*
2511 * Initiate forwarding of connections to port "port" on remote host through
2512 * the secure channel to host:port from local side.
2513 */
2514
2515 int
2516 channel_request_remote_forwarding(const char *listen_host, u_short listen_port,
2517 const char *host_to_connect, u_short port_to_connect)
2518 {
2519 int type, success = 0;
2520
2521 /* Record locally that connection to this host/port is permitted. */
2522 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2523 fatal("channel_request_remote_forwarding: too many forwards");
2524
2525 /* Send the forward request to the remote side. */
2526 if (compat20) {
2527 const char *address_to_bind;
2528 if (listen_host == NULL)
2529 address_to_bind = "localhost";
2530 else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0)
2531 address_to_bind = "";
2532 else
2533 address_to_bind = listen_host;
2534
2535 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2536 packet_put_cstring("tcpip-forward");
2537 packet_put_char(1); /* boolean: want reply */
2538 packet_put_cstring(address_to_bind);
2539 packet_put_int(listen_port);
2540 packet_send();
2541 packet_write_wait();
2542 /* Assume that server accepts the request */
2543 success = 1;
2544 } else {
2545 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2546 packet_put_int(listen_port);
2547 packet_put_cstring(host_to_connect);
2548 packet_put_int(port_to_connect);
2549 packet_send();
2550 packet_write_wait();
2551
2552 /* Wait for response from the remote side. */
2553 type = packet_read();
2554 switch (type) {
2555 case SSH_SMSG_SUCCESS:
2556 success = 1;
2557 break;
2558 case SSH_SMSG_FAILURE:
2559 break;
2560 default:
2561 /* Unknown packet */
2562 packet_disconnect("Protocol error for port forward request:"
2563 "received packet type %d.", type);
2564 }
2565 }
2566 if (success) {
2567 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2568 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2569 permitted_opens[num_permitted_opens].listen_port = listen_port;
2570 num_permitted_opens++;
2571 }
2572 return (success ? 0 : -1);
2573 }
2574
2575 /*
2576 * Request cancellation of remote forwarding of connection host:port from
2577 * local side.
2578 */
2579 void
2580 channel_request_rforward_cancel(const char *host, u_short port)
2581 {
2582 int i;
2583
2584 if (!compat20)
2585 return;
2586
2587 for (i = 0; i < num_permitted_opens; i++) {
2588 if (permitted_opens[i].host_to_connect != NULL &&
2589 permitted_opens[i].listen_port == port)
2590 break;
2591 }
2592 if (i >= num_permitted_opens) {
2593 debug("%s: requested forward not found", __func__);
2594 return;
2595 }
2596 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2597 packet_put_cstring("cancel-tcpip-forward");
2598 packet_put_char(0);
2599 packet_put_cstring(host == NULL ? "" : host);
2600 packet_put_int(port);
2601 packet_send();
2602
2603 permitted_opens[i].listen_port = 0;
2604 permitted_opens[i].port_to_connect = 0;
2605 xfree(permitted_opens[i].host_to_connect);
2606 permitted_opens[i].host_to_connect = NULL;
2607 }
2608
2609 /*
2610 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
2611 * listening for the port, and sends back a success reply (or disconnect
2612 * message if there was an error).
2613 */
2614 int
2615 channel_input_port_forward_request(int is_root, int gateway_ports)
2616 {
2617 u_short port, host_port;
2618 int success = 0;
2619 char *hostname;
2620
2621 /* Get arguments from the packet. */
2622 port = packet_get_int();
2623 hostname = packet_get_string(NULL);
2624 host_port = packet_get_int();
2625
2626 #ifndef HAVE_CYGWIN
2627 /*
2628 * Check that an unprivileged user is not trying to forward a
2629 * privileged port.
2630 */
2631 if (port < IPPORT_RESERVED && !is_root)
2632 packet_disconnect(
2633 "Requested forwarding of port %d but user is not root.",
2634 port);
2635 if (host_port == 0)
2636 packet_disconnect("Dynamic forwarding denied.");
2637 #endif
2638
2639 /* Initiate forwarding */
2640 success = channel_setup_local_fwd_listener(NULL, port, hostname,
2641 host_port, gateway_ports);
2642
2643 /* Free the argument string. */
2644 xfree(hostname);
2645
2646 return (success ? 0 : -1);
2647 }
2648
2649 /*
2650 * Permits opening to any host/port if permitted_opens[] is empty. This is
2651 * usually called by the server, because the user could connect to any port
2652 * anyway, and the server has no way to know but to trust the client anyway.
2653 */
2654 void
2655 channel_permit_all_opens(void)
2656 {
2657 if (num_permitted_opens == 0)
2658 all_opens_permitted = 1;
2659 }
2660
2661 void
2662 channel_add_permitted_opens(char *host, int port)
2663 {
2664 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2665 fatal("channel_add_permitted_opens: too many forwards");
2666 debug("allow port forwarding to host %s port %d", host, port);
2667
2668 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
2669 permitted_opens[num_permitted_opens].port_to_connect = port;
2670 num_permitted_opens++;
2671
2672 all_opens_permitted = 0;
2673 }
2674
2675 int
2676 channel_add_adm_permitted_opens(char *host, int port)
2677 {
2678 if (num_adm_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2679 fatal("channel_add_adm_permitted_opens: too many forwards");
2680 debug("config allows port forwarding to host %s port %d", host, port);
2681
2682 permitted_adm_opens[num_adm_permitted_opens].host_to_connect
2683 = xstrdup(host);
2684 permitted_adm_opens[num_adm_permitted_opens].port_to_connect = port;
2685 return ++num_adm_permitted_opens;
2686 }
2687
2688 void
2689 channel_clear_permitted_opens(void)
2690 {
2691 int i;
2692
2693 for (i = 0; i < num_permitted_opens; i++)
2694 if (permitted_opens[i].host_to_connect != NULL)
2695 xfree(permitted_opens[i].host_to_connect);
2696 num_permitted_opens = 0;
2697 }
2698
2699 void
2700 channel_clear_adm_permitted_opens(void)
2701 {
2702 int i;
2703
2704 for (i = 0; i < num_adm_permitted_opens; i++)
2705 if (permitted_adm_opens[i].host_to_connect != NULL)
2706 xfree(permitted_adm_opens[i].host_to_connect);
2707 num_adm_permitted_opens = 0;
2708 }
2709
2710 /* return socket to remote host, port */
2711 static int
2712 connect_to(const char *host, u_short port)
2713 {
2714 struct addrinfo hints, *ai, *aitop;
2715 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2716 int gaierr;
2717 int sock = -1;
2718
2719 memset(&hints, 0, sizeof(hints));
2720 hints.ai_family = IPv4or6;
2721 hints.ai_socktype = SOCK_STREAM;
2722 snprintf(strport, sizeof strport, "%d", port);
2723 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
2724 error("connect_to %.100s: unknown host (%s)", host,
2725 gai_strerror(gaierr));
2726 return -1;
2727 }
2728 for (ai = aitop; ai; ai = ai->ai_next) {
2729 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2730 continue;
2731 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2732 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2733 error("connect_to: getnameinfo failed");
2734 continue;
2735 }
2736 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2737 if (sock < 0) {
2738 if (ai->ai_next == NULL)
2739 error("socket: %.100s", strerror(errno));
2740 else
2741 verbose("socket: %.100s", strerror(errno));
2742 continue;
2743 }
2744 if (set_nonblock(sock) == -1)
2745 fatal("%s: set_nonblock(%d)", __func__, sock);
2746 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 &&
2747 errno != EINPROGRESS) {
2748 error("connect_to %.100s port %s: %.100s", ntop, strport,
2749 strerror(errno));
2750 close(sock);
2751 continue; /* fail -- try next */
2752 }
2753 break; /* success */
2754
2755 }
2756 freeaddrinfo(aitop);
2757 if (!ai) {
2758 error("connect_to %.100s port %d: failed.", host, port);
2759 return -1;
2760 }
2761 /* success */
2762 set_nodelay(sock);
2763 return sock;
2764 }
2765
2766 int
2767 channel_connect_by_listen_address(u_short listen_port)
2768 {
2769 int i;
2770
2771 for (i = 0; i < num_permitted_opens; i++)
2772 if (permitted_opens[i].host_to_connect != NULL &&
2773 permitted_opens[i].listen_port == listen_port)
2774 return connect_to(
2775 permitted_opens[i].host_to_connect,
2776 permitted_opens[i].port_to_connect);
2777 error("WARNING: Server requests forwarding for unknown listen_port %d",
2778 listen_port);
2779 return -1;
2780 }
2781
2782 /* Check if connecting to that port is permitted and connect. */
2783 int
2784 channel_connect_to(const char *host, u_short port)
2785 {
2786 int i, permit, permit_adm = 1;
2787
2788 permit = all_opens_permitted;
2789 if (!permit) {
2790 for (i = 0; i < num_permitted_opens; i++)
2791 if (permitted_opens[i].host_to_connect != NULL &&
2792 permitted_opens[i].port_to_connect == port &&
2793 strcmp(permitted_opens[i].host_to_connect, host) == 0)
2794 permit = 1;
2795 }
2796
2797 if (num_adm_permitted_opens > 0) {
2798 permit_adm = 0;
2799 for (i = 0; i < num_adm_permitted_opens; i++)
2800 if (permitted_adm_opens[i].host_to_connect != NULL &&
2801 permitted_adm_opens[i].port_to_connect == port &&
2802 strcmp(permitted_adm_opens[i].host_to_connect, host)
2803 == 0)
2804 permit_adm = 1;
2805 }
2806
2807 if (!permit || !permit_adm) {
2808 logit("Received request to connect to host %.100s port %d, "
2809 "but the request was denied.", host, port);
2810 return -1;
2811 }
2812 return connect_to(host, port);
2813 }
2814
2815 void
2816 channel_send_window_changes(void)
2817 {
2818 u_int i;
2819 struct winsize ws;
2820
2821 for (i = 0; i < channels_alloc; i++) {
2822 if (channels[i] == NULL || !channels[i]->client_tty ||
2823 channels[i]->type != SSH_CHANNEL_OPEN)
2824 continue;
2825 if (ioctl(channels[i]->rfd, TIOCGWINSZ, &ws) < 0)
2826 continue;
2827 channel_request_start(i, "window-change", 0);
2828 packet_put_int((u_int)ws.ws_col);
2829 packet_put_int((u_int)ws.ws_row);
2830 packet_put_int((u_int)ws.ws_xpixel);
2831 packet_put_int((u_int)ws.ws_ypixel);
2832 packet_send();
2833 }
2834 }
2835
2836 /* -- X11 forwarding */
2837
2838 /*
2839 * Creates an internet domain socket for listening for X11 connections.
2840 * Returns 0 and a suitable display number for the DISPLAY variable
2841 * stored in display_numberp , or -1 if an error occurs.
2842 */
2843 int
2844 x11_create_display_inet(int x11_display_offset, int x11_use_localhost,
2845 int single_connection, u_int *display_numberp, int **chanids)
2846 {
2847 Channel *nc = NULL;
2848 int display_number, sock;
2849 u_short port;
2850 struct addrinfo hints, *ai, *aitop;
2851 char strport[NI_MAXSERV];
2852 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
2853
2854 if (chanids == NULL)
2855 return -1;
2856
2857 for (display_number = x11_display_offset;
2858 display_number < MAX_DISPLAYS;
2859 display_number++) {
2860 port = 6000 + display_number;
2861 memset(&hints, 0, sizeof(hints));
2862 hints.ai_family = IPv4or6;
2863 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE;
2864 hints.ai_socktype = SOCK_STREAM;
2865 snprintf(strport, sizeof strport, "%d", port);
2866 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
2867 error("getaddrinfo: %.100s", gai_strerror(gaierr));
2868 return -1;
2869 }
2870 for (ai = aitop; ai; ai = ai->ai_next) {
2871 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2872 continue;
2873 sock = socket(ai->ai_family, ai->ai_socktype,
2874 ai->ai_protocol);
2875 if (sock < 0) {
2876 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
2877 error("socket: %.100s", strerror(errno));
2878 freeaddrinfo(aitop);
2879 return -1;
2880 } else {
2881 debug("x11_create_display_inet: Socket family %d not supported",
2882 ai->ai_family);
2883 continue;
2884 }
2885 }
2886 #ifdef IPV6_V6ONLY
2887 if (ai->ai_family == AF_INET6) {
2888 int on = 1;
2889 if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) < 0)
2890 error("setsockopt IPV6_V6ONLY: %.100s", strerror(errno));
2891 }
2892 #endif
2893 channel_set_reuseaddr(sock);
2894 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2895 debug2("bind port %d: %.100s", port, strerror(errno));
2896 close(sock);
2897
2898 if (ai->ai_next)
2899 continue;
2900
2901 for (n = 0; n < num_socks; n++) {
2902 close(socks[n]);
2903 }
2904 num_socks = 0;
2905 break;
2906 }
2907 socks[num_socks++] = sock;
2908 #ifndef DONT_TRY_OTHER_AF
2909 if (num_socks == NUM_SOCKS)
2910 break;
2911 #else
2912 if (x11_use_localhost) {
2913 if (num_socks == NUM_SOCKS)
2914 break;
2915 } else {
2916 break;
2917 }
2918 #endif
2919 }
2920 freeaddrinfo(aitop);
2921 if (num_socks > 0)
2922 break;
2923 }
2924 if (display_number >= MAX_DISPLAYS) {
2925 error("Failed to allocate internet-domain X11 display socket.");
2926 return -1;
2927 }
2928 /* Start listening for connections on the socket. */
2929 for (n = 0; n < num_socks; n++) {
2930 sock = socks[n];
2931 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2932 error("listen: %.100s", strerror(errno));
2933 close(sock);
2934 return -1;
2935 }
2936 }
2937
2938 /* Allocate a channel for each socket. */
2939 *chanids = xcalloc(num_socks + 1, sizeof(**chanids));
2940 for (n = 0; n < num_socks; n++) {
2941 sock = socks[n];
2942 nc = channel_new("x11 listener",
2943 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
2944 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2945 0, "X11 inet listener", 1);
2946 nc->single_connection = single_connection;
2947 (*chanids)[n] = nc->self;
2948 }
2949 (*chanids)[n] = -1;
2950
2951 /* Return the display number for the DISPLAY environment variable. */
2952 *display_numberp = display_number;
2953 return (0);
2954 }
2955
2956 static int
2957 connect_local_xsocket(u_int dnr)
2958 {
2959 int sock;
2960 struct sockaddr_un addr;
2961
2962 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2963 if (sock < 0)
2964 error("socket: %.100s", strerror(errno));
2965 memset(&addr, 0, sizeof(addr));
2966 addr.sun_family = AF_UNIX;
2967 snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr);
2968 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0)
2969 return sock;
2970 close(sock);
2971 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
2972 return -1;
2973 }
2974
2975 int
2976 x11_connect_display(void)
2977 {
2978 u_int display_number;
2979 const char *display;
2980 char buf[1024], *cp;
2981 struct addrinfo hints, *ai, *aitop;
2982 char strport[NI_MAXSERV];
2983 int gaierr, sock = 0;
2984
2985 /* Try to open a socket for the local X server. */
2986 display = getenv("DISPLAY");
2987 if (!display) {
2988 error("DISPLAY not set.");
2989 return -1;
2990 }
2991 /*
2992 * Now we decode the value of the DISPLAY variable and make a
2993 * connection to the real X server.
2994 */
2995
2996 /*
2997 * Check if it is a unix domain socket. Unix domain displays are in
2998 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
2999 */
3000 if (strncmp(display, "unix:", 5) == 0 ||
3001 display[0] == ':') {
3002 /* Connect to the unix domain socket. */
3003 if (sscanf(strrchr(display, ':') + 1, "%u", &display_number) != 1) {
3004 error("Could not parse display number from DISPLAY: %.100s",
3005 display);
3006 return -1;
3007 }
3008 /* Create a socket. */
3009 sock = connect_local_xsocket(display_number);
3010 if (sock < 0)
3011 return -1;
3012
3013 /* OK, we now have a connection to the display. */
3014 return sock;
3015 }
3016 /*
3017 * Connect to an inet socket. The DISPLAY value is supposedly
3018 * hostname:d[.s], where hostname may also be numeric IP address.
3019 */
3020 strlcpy(buf, display, sizeof(buf));
3021 cp = strchr(buf, ':');
3022 if (!cp) {
3023 error("Could not find ':' in DISPLAY: %.100s", display);
3024 return -1;
3025 }
3026 *cp = 0;
3027 /* buf now contains the host name. But first we parse the display number. */
3028 if (sscanf(cp + 1, "%u", &display_number) != 1) {
3029 error("Could not parse display number from DISPLAY: %.100s",
3030 display);
3031 return -1;
3032 }
3033
3034 /* Look up the host address */
3035 memset(&hints, 0, sizeof(hints));
3036 hints.ai_family = IPv4or6;
3037 hints.ai_socktype = SOCK_STREAM;
3038 snprintf(strport, sizeof strport, "%u", 6000 + display_number);
3039 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
3040 error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr));
3041 return -1;
3042 }
3043 for (ai = aitop; ai; ai = ai->ai_next) {
3044 /* Create a socket. */
3045 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
3046 if (sock < 0) {
3047 debug2("socket: %.100s", strerror(errno));
3048 continue;
3049 }
3050 /* Connect it to the display. */
3051 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
3052 debug2("connect %.100s port %u: %.100s", buf,
3053 6000 + display_number, strerror(errno));
3054 close(sock);
3055 continue;
3056 }
3057 /* Success */
3058 break;
3059 }
3060 freeaddrinfo(aitop);
3061 if (!ai) {
3062 error("connect %.100s port %u: %.100s", buf, 6000 + display_number,
3063 strerror(errno));
3064 return -1;
3065 }
3066 set_nodelay(sock);
3067 return sock;
3068 }
3069
3070 /*
3071 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
3072 * the remote channel number. We should do whatever we want, and respond
3073 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
3074 */
3075
3076 /* ARGSUSED */
3077 void
3078 x11_input_open(int type, u_int32_t seq, void *ctxt)
3079 {
3080 Channel *c = NULL;
3081 int remote_id, sock = 0;
3082 char *remote_host;
3083
3084 debug("Received X11 open request.");
3085
3086 remote_id = packet_get_int();
3087
3088 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
3089 remote_host = packet_get_string(NULL);
3090 } else {
3091 remote_host = xstrdup("unknown (remote did not supply name)");
3092 }
3093 packet_check_eom();
3094
3095 /* Obtain a connection to the real X display. */
3096 sock = x11_connect_display();
3097 if (sock != -1) {
3098 /* Allocate a channel for this connection. */
3099 c = channel_new("connected x11 socket",
3100 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
3101 remote_host, 1);
3102 c->remote_id = remote_id;
3103 c->force_drain = 1;
3104 }
3105 xfree(remote_host);
3106 if (c == NULL) {
3107 /* Send refusal to the remote host. */
3108 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3109 packet_put_int(remote_id);
3110 } else {
3111 /* Send a confirmation to the remote host. */
3112 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
3113 packet_put_int(remote_id);
3114 packet_put_int(c->self);
3115 }
3116 packet_send();
3117 }
3118
3119 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
3120 /* ARGSUSED */
3121 void
3122 deny_input_open(int type, u_int32_t seq, void *ctxt)
3123 {
3124 int rchan = packet_get_int();
3125
3126 switch (type) {
3127 case SSH_SMSG_AGENT_OPEN:
3128 error("Warning: ssh server tried agent forwarding.");
3129 break;
3130 case SSH_SMSG_X11_OPEN:
3131 error("Warning: ssh server tried X11 forwarding.");
3132 break;
3133 default:
3134 error("deny_input_open: type %d", type);
3135 break;
3136 }
3137 error("Warning: this is probably a break-in attempt by a malicious server.");
3138 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3139 packet_put_int(rchan);
3140 packet_send();
3141 }
3142
3143 /*
3144 * Requests forwarding of X11 connections, generates fake authentication
3145 * data, and enables authentication spoofing.
3146 * This should be called in the client only.
3147 */
3148 void
3149 x11_request_forwarding_with_spoofing(int client_session_id, const char *disp,
3150 const char *proto, const char *data)
3151 {
3152 u_int data_len = (u_int) strlen(data) / 2;
3153 u_int i, value;
3154 char *new_data;
3155 int screen_number;
3156 const char *cp;
3157 u_int32_t rnd = 0;
3158
3159 if (x11_saved_display == NULL)
3160 x11_saved_display = xstrdup(disp);
3161 else if (strcmp(disp, x11_saved_display) != 0) {
3162 error("x11_request_forwarding_with_spoofing: different "
3163 "$DISPLAY already forwarded");
3164 return;
3165 }
3166
3167 cp = disp;
3168 if (disp)
3169 cp = strchr(disp, ':');
3170 if (cp)
3171 cp = strchr(cp, '.');
3172 if (cp)
3173 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL);
3174 else
3175 screen_number = 0;
3176
3177 if (x11_saved_proto == NULL) {
3178 /* Save protocol name. */
3179 x11_saved_proto = xstrdup(proto);
3180 /*
3181 * Extract real authentication data and generate fake data
3182 * of the same length.
3183 */
3184 x11_saved_data = xmalloc(data_len);
3185 x11_fake_data = xmalloc(data_len);
3186 for (i = 0; i < data_len; i++) {
3187 if (sscanf(data + 2 * i, "%2x", &value) != 1)
3188 fatal("x11_request_forwarding: bad "
3189 "authentication data: %.100s", data);
3190 if (i % 4 == 0)
3191 rnd = arc4random();
3192 x11_saved_data[i] = value;
3193 x11_fake_data[i] = rnd & 0xff;
3194 rnd >>= 8;
3195 }
3196 x11_saved_data_len = data_len;
3197 x11_fake_data_len = data_len;
3198 }
3199
3200 /* Convert the fake data into hex. */
3201 new_data = tohex(x11_fake_data, data_len);
3202
3203 /* Send the request packet. */
3204 if (compat20) {
3205 channel_request_start(client_session_id, "x11-req", 0);
3206 packet_put_char(0); /* XXX bool single connection */
3207 } else {
3208 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
3209 }
3210 packet_put_cstring(proto);
3211 packet_put_cstring(new_data);
3212 packet_put_int(screen_number);
3213 packet_send();
3214 packet_write_wait();
3215 xfree(new_data);
3216 }
3217
3218
3219 /* -- agent forwarding */
3220
3221 /* Sends a message to the server to request authentication fd forwarding. */
3222
3223 void
3224 auth_request_forwarding(void)
3225 {
3226 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
3227 packet_send();
3228 packet_write_wait();
3229 }
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