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- dtucker@cvs.openbsd.org 2006/07/19 13:07:10
[openssh-git.git] / channels.c
blob9aaf7e9d7a7dcb5f8d1803e31a0281be53a785e4
1 /* $OpenBSD: channels.c,v 1.257 2006/07/17 12:06:00 dtucker Exp $ */
2 /*
3 * Author: Tatu Ylonen <ylo@cs.hut.fi>
4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5 * All rights reserved
6 * This file contains functions for generic socket connection forwarding.
7 * There is also code for initiating connection forwarding for X11 connections,
8 * arbitrary tcp/ip connections, and the authentication agent connection.
9 *
10 * As far as I am concerned, the code I have written for this software
11 * can be used freely for any purpose. Any derived versions of this
12 * software must be clearly marked as such, and if the derived work is
13 * incompatible with the protocol description in the RFC file, it must be
14 * called by a name other than "ssh" or "Secure Shell".
15 *
16 * SSH2 support added by Markus Friedl.
17 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved.
18 * Copyright (c) 1999 Dug Song. All rights reserved.
19 * Copyright (c) 1999 Theo de Raadt. All rights reserved.
20 *
21 * Redistribution and use in source and binary forms, with or without
22 * modification, are permitted provided that the following conditions
23 * are met:
24 * 1. Redistributions of source code must retain the above copyright
25 * notice, this list of conditions and the following disclaimer.
26 * 2. Redistributions in binary form must reproduce the above copyright
27 * notice, this list of conditions and the following disclaimer in the
28 * documentation and/or other materials provided with the distribution.
29 *
30 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
31 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
32 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
33 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
34 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
35 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
36 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
37 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
38 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
39 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
40 */
41
42 #include "includes.h"
43
44 #include <sys/ioctl.h>
45 #include <sys/types.h>
46 #include <sys/un.h>
47 #include <sys/socket.h>
48
49 #include <netinet/in.h>
50 #include <arpa/inet.h>
51
52 #include <errno.h>
53 #if defined(HAVE_NETDB_H)
54 # include <netdb.h>
55 #endif
56 #include <termios.h>
57 #include <unistd.h>
58
59 #include "ssh.h"
60 #include "ssh1.h"
61 #include "ssh2.h"
62 #include "packet.h"
63 #include "xmalloc.h"
64 #include "log.h"
65 #include "misc.h"
66 #include "channels.h"
67 #include "compat.h"
68 #include "canohost.h"
69 #include "key.h"
70 #include "authfd.h"
71 #include "pathnames.h"
72 #include "bufaux.h"
73
74 /* -- channel core */
75
76 /*
77 * Pointer to an array containing all allocated channels. The array is
78 * dynamically extended as needed.
79 */
80 static Channel **channels = NULL;
81
82 /*
83 * Size of the channel array. All slots of the array must always be
84 * initialized (at least the type field); unused slots set to NULL
85 */
86 static u_int channels_alloc = 0;
87
88 /*
89 * Maximum file descriptor value used in any of the channels. This is
90 * updated in channel_new.
91 */
92 static int channel_max_fd = 0;
93
94
95 /* -- tcp forwarding */
96
97 /*
98 * Data structure for storing which hosts are permitted for forward requests.
99 * The local sides of any remote forwards are stored in this array to prevent
100 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local
101 * network (which might be behind a firewall).
102 */
103 typedef struct {
104 char *host_to_connect; /* Connect to 'host'. */
105 u_short port_to_connect; /* Connect to 'port'. */
106 u_short listen_port; /* Remote side should listen port number. */
107 } ForwardPermission;
108
109 /* List of all permitted host/port pairs to connect by the user. */
110 static ForwardPermission permitted_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
111
112 /* List of all permitted host/port pairs to connect by the admin. */
113 static ForwardPermission permitted_adm_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
114
115 /* Number of permitted host/port pairs in the array permitted by the user. */
116 static int num_permitted_opens = 0;
117
118 /* Number of permitted host/port pair in the array permitted by the admin. */
119 static int num_adm_permitted_opens = 0;
120
121 /*
122 * If this is true, all opens are permitted. This is the case on the server
123 * on which we have to trust the client anyway, and the user could do
124 * anything after logging in anyway.
125 */
126 static int all_opens_permitted = 0;
127
128
129 /* -- X11 forwarding */
130
131 /* Maximum number of fake X11 displays to try. */
132 #define MAX_DISPLAYS 1000
133
134 /* Saved X11 local (client) display. */
135 static char *x11_saved_display = NULL;
136
137 /* Saved X11 authentication protocol name. */
138 static char *x11_saved_proto = NULL;
139
140 /* Saved X11 authentication data. This is the real data. */
141 static char *x11_saved_data = NULL;
142 static u_int x11_saved_data_len = 0;
143
144 /*
145 * Fake X11 authentication data. This is what the server will be sending us;
146 * we should replace any occurrences of this by the real data.
147 */
148 static u_char *x11_fake_data = NULL;
149 static u_int x11_fake_data_len;
150
151
152 /* -- agent forwarding */
153
154 #define NUM_SOCKS 10
155
156 /* AF_UNSPEC or AF_INET or AF_INET6 */
157 static int IPv4or6 = AF_UNSPEC;
158
159 /* helper */
160 static void port_open_helper(Channel *c, char *rtype);
161
162 /* -- channel core */
163
164 Channel *
165 channel_by_id(int id)
166 {
167 Channel *c;
168
169 if (id < 0 || (u_int)id >= channels_alloc) {
170 logit("channel_by_id: %d: bad id", id);
171 return NULL;
172 }
173 c = channels[id];
174 if (c == NULL) {
175 logit("channel_by_id: %d: bad id: channel free", id);
176 return NULL;
177 }
178 return c;
179 }
180
181 /*
182 * Returns the channel if it is allowed to receive protocol messages.
183 * Private channels, like listening sockets, may not receive messages.
184 */
185 Channel *
186 channel_lookup(int id)
187 {
188 Channel *c;
189
190 if ((c = channel_by_id(id)) == NULL)
191 return (NULL);
192
193 switch (c->type) {
194 case SSH_CHANNEL_X11_OPEN:
195 case SSH_CHANNEL_LARVAL:
196 case SSH_CHANNEL_CONNECTING:
197 case SSH_CHANNEL_DYNAMIC:
198 case SSH_CHANNEL_OPENING:
199 case SSH_CHANNEL_OPEN:
200 case SSH_CHANNEL_INPUT_DRAINING:
201 case SSH_CHANNEL_OUTPUT_DRAINING:
202 return (c);
203 }
204 logit("Non-public channel %d, type %d.", id, c->type);
205 return (NULL);
206 }
207
208 /*
209 * Register filedescriptors for a channel, used when allocating a channel or
210 * when the channel consumer/producer is ready, e.g. shell exec'd
211 */
212 static void
213 channel_register_fds(Channel *c, int rfd, int wfd, int efd,
214 int extusage, int nonblock)
215 {
216 /* Update the maximum file descriptor value. */
217 channel_max_fd = MAX(channel_max_fd, rfd);
218 channel_max_fd = MAX(channel_max_fd, wfd);
219 channel_max_fd = MAX(channel_max_fd, efd);
220
221 /* XXX set close-on-exec -markus */
222
223 c->rfd = rfd;
224 c->wfd = wfd;
225 c->sock = (rfd == wfd) ? rfd : -1;
226 c->ctl_fd = -1; /* XXX: set elsewhere */
227 c->efd = efd;
228 c->extended_usage = extusage;
229
230 /* XXX ugly hack: nonblock is only set by the server */
231 if (nonblock && isatty(c->rfd)) {
232 debug2("channel %d: rfd %d isatty", c->self, c->rfd);
233 c->isatty = 1;
234 if (!isatty(c->wfd)) {
235 error("channel %d: wfd %d is not a tty?",
236 c->self, c->wfd);
237 }
238 } else {
239 c->isatty = 0;
240 }
241 c->wfd_isatty = isatty(c->wfd);
242
243 /* enable nonblocking mode */
244 if (nonblock) {
245 if (rfd != -1)
246 set_nonblock(rfd);
247 if (wfd != -1)
248 set_nonblock(wfd);
249 if (efd != -1)
250 set_nonblock(efd);
251 }
252 }
253
254 /*
255 * Allocate a new channel object and set its type and socket. This will cause
256 * remote_name to be freed.
257 */
258 Channel *
259 channel_new(char *ctype, int type, int rfd, int wfd, int efd,
260 u_int window, u_int maxpack, int extusage, char *remote_name, int nonblock)
261 {
262 int found;
263 u_int i;
264 Channel *c;
265
266 /* Do initial allocation if this is the first call. */
267 if (channels_alloc == 0) {
268 channels_alloc = 10;
269 channels = xcalloc(channels_alloc, sizeof(Channel *));
270 for (i = 0; i < channels_alloc; i++)
271 channels[i] = NULL;
272 }
273 /* Try to find a free slot where to put the new channel. */
274 for (found = -1, i = 0; i < channels_alloc; i++)
275 if (channels[i] == NULL) {
276 /* Found a free slot. */
277 found = (int)i;
278 break;
279 }
280 if (found < 0) {
281 /* There are no free slots. Take last+1 slot and expand the array. */
282 found = channels_alloc;
283 if (channels_alloc > 10000)
284 fatal("channel_new: internal error: channels_alloc %d "
285 "too big.", channels_alloc);
286 channels = xrealloc(channels, channels_alloc + 10,
287 sizeof(Channel *));
288 channels_alloc += 10;
289 debug2("channel: expanding %d", channels_alloc);
290 for (i = found; i < channels_alloc; i++)
291 channels[i] = NULL;
292 }
293 /* Initialize and return new channel. */
294 c = channels[found] = xcalloc(1, sizeof(Channel));
295 buffer_init(&c->input);
296 buffer_init(&c->output);
297 buffer_init(&c->extended);
298 c->ostate = CHAN_OUTPUT_OPEN;
299 c->istate = CHAN_INPUT_OPEN;
300 c->flags = 0;
301 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
302 c->self = found;
303 c->type = type;
304 c->ctype = ctype;
305 c->local_window = window;
306 c->local_window_max = window;
307 c->local_consumed = 0;
308 c->local_maxpacket = maxpack;
309 c->remote_id = -1;
310 c->remote_name = xstrdup(remote_name);
311 c->remote_window = 0;
312 c->remote_maxpacket = 0;
313 c->force_drain = 0;
314 c->single_connection = 0;
315 c->detach_user = NULL;
316 c->detach_close = 0;
317 c->confirm = NULL;
318 c->confirm_ctx = NULL;
319 c->input_filter = NULL;
320 c->output_filter = NULL;
321 debug("channel %d: new [%s]", found, remote_name);
322 return c;
323 }
324
325 static int
326 channel_find_maxfd(void)
327 {
328 u_int i;
329 int max = 0;
330 Channel *c;
331
332 for (i = 0; i < channels_alloc; i++) {
333 c = channels[i];
334 if (c != NULL) {
335 max = MAX(max, c->rfd);
336 max = MAX(max, c->wfd);
337 max = MAX(max, c->efd);
338 }
339 }
340 return max;
341 }
342
343 int
344 channel_close_fd(int *fdp)
345 {
346 int ret = 0, fd = *fdp;
347
348 if (fd != -1) {
349 ret = close(fd);
350 *fdp = -1;
351 if (fd == channel_max_fd)
352 channel_max_fd = channel_find_maxfd();
353 }
354 return ret;
355 }
356
357 /* Close all channel fd/socket. */
358 static void
359 channel_close_fds(Channel *c)
360 {
361 debug3("channel %d: close_fds r %d w %d e %d c %d",
362 c->self, c->rfd, c->wfd, c->efd, c->ctl_fd);
363
364 channel_close_fd(&c->sock);
365 channel_close_fd(&c->ctl_fd);
366 channel_close_fd(&c->rfd);
367 channel_close_fd(&c->wfd);
368 channel_close_fd(&c->efd);
369 }
370
371 /* Free the channel and close its fd/socket. */
372 void
373 channel_free(Channel *c)
374 {
375 char *s;
376 u_int i, n;
377
378 for (n = 0, i = 0; i < channels_alloc; i++)
379 if (channels[i])
380 n++;
381 debug("channel %d: free: %s, nchannels %u", c->self,
382 c->remote_name ? c->remote_name : "???", n);
383
384 s = channel_open_message();
385 debug3("channel %d: status: %s", c->self, s);
386 xfree(s);
387
388 if (c->sock != -1)
389 shutdown(c->sock, SHUT_RDWR);
390 if (c->ctl_fd != -1)
391 shutdown(c->ctl_fd, SHUT_RDWR);
392 channel_close_fds(c);
393 buffer_free(&c->input);
394 buffer_free(&c->output);
395 buffer_free(&c->extended);
396 if (c->remote_name) {
397 xfree(c->remote_name);
398 c->remote_name = NULL;
399 }
400 channels[c->self] = NULL;
401 xfree(c);
402 }
403
404 void
405 channel_free_all(void)
406 {
407 u_int i;
408
409 for (i = 0; i < channels_alloc; i++)
410 if (channels[i] != NULL)
411 channel_free(channels[i]);
412 }
413
414 /*
415 * Closes the sockets/fds of all channels. This is used to close extra file
416 * descriptors after a fork.
417 */
418 void
419 channel_close_all(void)
420 {
421 u_int i;
422
423 for (i = 0; i < channels_alloc; i++)
424 if (channels[i] != NULL)
425 channel_close_fds(channels[i]);
426 }
427
428 /*
429 * Stop listening to channels.
430 */
431 void
432 channel_stop_listening(void)
433 {
434 u_int i;
435 Channel *c;
436
437 for (i = 0; i < channels_alloc; i++) {
438 c = channels[i];
439 if (c != NULL) {
440 switch (c->type) {
441 case SSH_CHANNEL_AUTH_SOCKET:
442 case SSH_CHANNEL_PORT_LISTENER:
443 case SSH_CHANNEL_RPORT_LISTENER:
444 case SSH_CHANNEL_X11_LISTENER:
445 channel_close_fd(&c->sock);
446 channel_free(c);
447 break;
448 }
449 }
450 }
451 }
452
453 /*
454 * Returns true if no channel has too much buffered data, and false if one or
455 * more channel is overfull.
456 */
457 int
458 channel_not_very_much_buffered_data(void)
459 {
460 u_int i;
461 Channel *c;
462
463 for (i = 0; i < channels_alloc; i++) {
464 c = channels[i];
465 if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
466 #if 0
467 if (!compat20 &&
468 buffer_len(&c->input) > packet_get_maxsize()) {
469 debug2("channel %d: big input buffer %d",
470 c->self, buffer_len(&c->input));
471 return 0;
472 }
473 #endif
474 if (buffer_len(&c->output) > packet_get_maxsize()) {
475 debug2("channel %d: big output buffer %u > %u",
476 c->self, buffer_len(&c->output),
477 packet_get_maxsize());
478 return 0;
479 }
480 }
481 }
482 return 1;
483 }
484
485 /* Returns true if any channel is still open. */
486 int
487 channel_still_open(void)
488 {
489 u_int i;
490 Channel *c;
491
492 for (i = 0; i < channels_alloc; i++) {
493 c = channels[i];
494 if (c == NULL)
495 continue;
496 switch (c->type) {
497 case SSH_CHANNEL_X11_LISTENER:
498 case SSH_CHANNEL_PORT_LISTENER:
499 case SSH_CHANNEL_RPORT_LISTENER:
500 case SSH_CHANNEL_CLOSED:
501 case SSH_CHANNEL_AUTH_SOCKET:
502 case SSH_CHANNEL_DYNAMIC:
503 case SSH_CHANNEL_CONNECTING:
504 case SSH_CHANNEL_ZOMBIE:
505 continue;
506 case SSH_CHANNEL_LARVAL:
507 if (!compat20)
508 fatal("cannot happen: SSH_CHANNEL_LARVAL");
509 continue;
510 case SSH_CHANNEL_OPENING:
511 case SSH_CHANNEL_OPEN:
512 case SSH_CHANNEL_X11_OPEN:
513 return 1;
514 case SSH_CHANNEL_INPUT_DRAINING:
515 case SSH_CHANNEL_OUTPUT_DRAINING:
516 if (!compat13)
517 fatal("cannot happen: OUT_DRAIN");
518 return 1;
519 default:
520 fatal("channel_still_open: bad channel type %d", c->type);
521 /* NOTREACHED */
522 }
523 }
524 return 0;
525 }
526
527 /* Returns the id of an open channel suitable for keepaliving */
528 int
529 channel_find_open(void)
530 {
531 u_int i;
532 Channel *c;
533
534 for (i = 0; i < channels_alloc; i++) {
535 c = channels[i];
536 if (c == NULL || c->remote_id < 0)
537 continue;
538 switch (c->type) {
539 case SSH_CHANNEL_CLOSED:
540 case SSH_CHANNEL_DYNAMIC:
541 case SSH_CHANNEL_X11_LISTENER:
542 case SSH_CHANNEL_PORT_LISTENER:
543 case SSH_CHANNEL_RPORT_LISTENER:
544 case SSH_CHANNEL_OPENING:
545 case SSH_CHANNEL_CONNECTING:
546 case SSH_CHANNEL_ZOMBIE:
547 continue;
548 case SSH_CHANNEL_LARVAL:
549 case SSH_CHANNEL_AUTH_SOCKET:
550 case SSH_CHANNEL_OPEN:
551 case SSH_CHANNEL_X11_OPEN:
552 return i;
553 case SSH_CHANNEL_INPUT_DRAINING:
554 case SSH_CHANNEL_OUTPUT_DRAINING:
555 if (!compat13)
556 fatal("cannot happen: OUT_DRAIN");
557 return i;
558 default:
559 fatal("channel_find_open: bad channel type %d", c->type);
560 /* NOTREACHED */
561 }
562 }
563 return -1;
564 }
565
566
567 /*
568 * Returns a message describing the currently open forwarded connections,
569 * suitable for sending to the client. The message contains crlf pairs for
570 * newlines.
571 */
572 char *
573 channel_open_message(void)
574 {
575 Buffer buffer;
576 Channel *c;
577 char buf[1024], *cp;
578 u_int i;
579
580 buffer_init(&buffer);
581 snprintf(buf, sizeof buf, "The following connections are open:\r\n");
582 buffer_append(&buffer, buf, strlen(buf));
583 for (i = 0; i < channels_alloc; i++) {
584 c = channels[i];
585 if (c == NULL)
586 continue;
587 switch (c->type) {
588 case SSH_CHANNEL_X11_LISTENER:
589 case SSH_CHANNEL_PORT_LISTENER:
590 case SSH_CHANNEL_RPORT_LISTENER:
591 case SSH_CHANNEL_CLOSED:
592 case SSH_CHANNEL_AUTH_SOCKET:
593 case SSH_CHANNEL_ZOMBIE:
594 continue;
595 case SSH_CHANNEL_LARVAL:
596 case SSH_CHANNEL_OPENING:
597 case SSH_CHANNEL_CONNECTING:
598 case SSH_CHANNEL_DYNAMIC:
599 case SSH_CHANNEL_OPEN:
600 case SSH_CHANNEL_X11_OPEN:
601 case SSH_CHANNEL_INPUT_DRAINING:
602 case SSH_CHANNEL_OUTPUT_DRAINING:
603 snprintf(buf, sizeof buf,
604 " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d cfd %d)\r\n",
605 c->self, c->remote_name,
606 c->type, c->remote_id,
607 c->istate, buffer_len(&c->input),
608 c->ostate, buffer_len(&c->output),
609 c->rfd, c->wfd, c->ctl_fd);
610 buffer_append(&buffer, buf, strlen(buf));
611 continue;
612 default:
613 fatal("channel_open_message: bad channel type %d", c->type);
614 /* NOTREACHED */
615 }
616 }
617 buffer_append(&buffer, "\0", 1);
618 cp = xstrdup(buffer_ptr(&buffer));
619 buffer_free(&buffer);
620 return cp;
621 }
622
623 void
624 channel_send_open(int id)
625 {
626 Channel *c = channel_lookup(id);
627
628 if (c == NULL) {
629 logit("channel_send_open: %d: bad id", id);
630 return;
631 }
632 debug2("channel %d: send open", id);
633 packet_start(SSH2_MSG_CHANNEL_OPEN);
634 packet_put_cstring(c->ctype);
635 packet_put_int(c->self);
636 packet_put_int(c->local_window);
637 packet_put_int(c->local_maxpacket);
638 packet_send();
639 }
640
641 void
642 channel_request_start(int id, char *service, int wantconfirm)
643 {
644 Channel *c = channel_lookup(id);
645
646 if (c == NULL) {
647 logit("channel_request_start: %d: unknown channel id", id);
648 return;
649 }
650 debug2("channel %d: request %s confirm %d", id, service, wantconfirm);
651 packet_start(SSH2_MSG_CHANNEL_REQUEST);
652 packet_put_int(c->remote_id);
653 packet_put_cstring(service);
654 packet_put_char(wantconfirm);
655 }
656
657 void
658 channel_register_confirm(int id, channel_callback_fn *fn, void *ctx)
659 {
660 Channel *c = channel_lookup(id);
661
662 if (c == NULL) {
663 logit("channel_register_comfirm: %d: bad id", id);
664 return;
665 }
666 c->confirm = fn;
667 c->confirm_ctx = ctx;
668 }
669
670 void
671 channel_register_cleanup(int id, channel_callback_fn *fn, int do_close)
672 {
673 Channel *c = channel_by_id(id);
674
675 if (c == NULL) {
676 logit("channel_register_cleanup: %d: bad id", id);
677 return;
678 }
679 c->detach_user = fn;
680 c->detach_close = do_close;
681 }
682
683 void
684 channel_cancel_cleanup(int id)
685 {
686 Channel *c = channel_by_id(id);
687
688 if (c == NULL) {
689 logit("channel_cancel_cleanup: %d: bad id", id);
690 return;
691 }
692 c->detach_user = NULL;
693 c->detach_close = 0;
694 }
695
696 void
697 channel_register_filter(int id, channel_infilter_fn *ifn,
698 channel_outfilter_fn *ofn)
699 {
700 Channel *c = channel_lookup(id);
701
702 if (c == NULL) {
703 logit("channel_register_filter: %d: bad id", id);
704 return;
705 }
706 c->input_filter = ifn;
707 c->output_filter = ofn;
708 }
709
710 void
711 channel_set_fds(int id, int rfd, int wfd, int efd,
712 int extusage, int nonblock, u_int window_max)
713 {
714 Channel *c = channel_lookup(id);
715
716 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
717 fatal("channel_activate for non-larval channel %d.", id);
718 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
719 c->type = SSH_CHANNEL_OPEN;
720 c->local_window = c->local_window_max = window_max;
721 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
722 packet_put_int(c->remote_id);
723 packet_put_int(c->local_window);
724 packet_send();
725 }
726
727 /*
728 * 'channel_pre*' are called just before select() to add any bits relevant to
729 * channels in the select bitmasks.
730 */
731 /*
732 * 'channel_post*': perform any appropriate operations for channels which
733 * have events pending.
734 */
735 typedef void chan_fn(Channel *c, fd_set *readset, fd_set *writeset);
736 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
737 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
738
739 static void
740 channel_pre_listener(Channel *c, fd_set *readset, fd_set *writeset)
741 {
742 FD_SET(c->sock, readset);
743 }
744
745 static void
746 channel_pre_connecting(Channel *c, fd_set *readset, fd_set *writeset)
747 {
748 debug3("channel %d: waiting for connection", c->self);
749 FD_SET(c->sock, writeset);
750 }
751
752 static void
753 channel_pre_open_13(Channel *c, fd_set *readset, fd_set *writeset)
754 {
755 if (buffer_len(&c->input) < packet_get_maxsize())
756 FD_SET(c->sock, readset);
757 if (buffer_len(&c->output) > 0)
758 FD_SET(c->sock, writeset);
759 }
760
761 static void
762 channel_pre_open(Channel *c, fd_set *readset, fd_set *writeset)
763 {
764 u_int limit = compat20 ? c->remote_window : packet_get_maxsize();
765
766 if (c->istate == CHAN_INPUT_OPEN &&
767 limit > 0 &&
768 buffer_len(&c->input) < limit &&
769 buffer_check_alloc(&c->input, CHAN_RBUF))
770 FD_SET(c->rfd, readset);
771 if (c->ostate == CHAN_OUTPUT_OPEN ||
772 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
773 if (buffer_len(&c->output) > 0) {
774 FD_SET(c->wfd, writeset);
775 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
776 if (CHANNEL_EFD_OUTPUT_ACTIVE(c))
777 debug2("channel %d: obuf_empty delayed efd %d/(%d)",
778 c->self, c->efd, buffer_len(&c->extended));
779 else
780 chan_obuf_empty(c);
781 }
782 }
783 /** XXX check close conditions, too */
784 if (compat20 && c->efd != -1) {
785 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
786 buffer_len(&c->extended) > 0)
787 FD_SET(c->efd, writeset);
788 else if (!(c->flags & CHAN_EOF_SENT) &&
789 c->extended_usage == CHAN_EXTENDED_READ &&
790 buffer_len(&c->extended) < c->remote_window)
791 FD_SET(c->efd, readset);
792 }
793 /* XXX: What about efd? races? */
794 if (compat20 && c->ctl_fd != -1 &&
795 c->istate == CHAN_INPUT_OPEN && c->ostate == CHAN_OUTPUT_OPEN)
796 FD_SET(c->ctl_fd, readset);
797 }
798
799 static void
800 channel_pre_input_draining(Channel *c, fd_set *readset, fd_set *writeset)
801 {
802 if (buffer_len(&c->input) == 0) {
803 packet_start(SSH_MSG_CHANNEL_CLOSE);
804 packet_put_int(c->remote_id);
805 packet_send();
806 c->type = SSH_CHANNEL_CLOSED;
807 debug2("channel %d: closing after input drain.", c->self);
808 }
809 }
810
811 static void
812 channel_pre_output_draining(Channel *c, fd_set *readset, fd_set *writeset)
813 {
814 if (buffer_len(&c->output) == 0)
815 chan_mark_dead(c);
816 else
817 FD_SET(c->sock, writeset);
818 }
819
820 /*
821 * This is a special state for X11 authentication spoofing. An opened X11
822 * connection (when authentication spoofing is being done) remains in this
823 * state until the first packet has been completely read. The authentication
824 * data in that packet is then substituted by the real data if it matches the
825 * fake data, and the channel is put into normal mode.
826 * XXX All this happens at the client side.
827 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
828 */
829 static int
830 x11_open_helper(Buffer *b)
831 {
832 u_char *ucp;
833 u_int proto_len, data_len;
834
835 /* Check if the fixed size part of the packet is in buffer. */
836 if (buffer_len(b) < 12)
837 return 0;
838
839 /* Parse the lengths of variable-length fields. */
840 ucp = buffer_ptr(b);
841 if (ucp[0] == 0x42) { /* Byte order MSB first. */
842 proto_len = 256 * ucp[6] + ucp[7];
843 data_len = 256 * ucp[8] + ucp[9];
844 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
845 proto_len = ucp[6] + 256 * ucp[7];
846 data_len = ucp[8] + 256 * ucp[9];
847 } else {
848 debug2("Initial X11 packet contains bad byte order byte: 0x%x",
849 ucp[0]);
850 return -1;
851 }
852
853 /* Check if the whole packet is in buffer. */
854 if (buffer_len(b) <
855 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
856 return 0;
857
858 /* Check if authentication protocol matches. */
859 if (proto_len != strlen(x11_saved_proto) ||
860 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
861 debug2("X11 connection uses different authentication protocol.");
862 return -1;
863 }
864 /* Check if authentication data matches our fake data. */
865 if (data_len != x11_fake_data_len ||
866 memcmp(ucp + 12 + ((proto_len + 3) & ~3),
867 x11_fake_data, x11_fake_data_len) != 0) {
868 debug2("X11 auth data does not match fake data.");
869 return -1;
870 }
871 /* Check fake data length */
872 if (x11_fake_data_len != x11_saved_data_len) {
873 error("X11 fake_data_len %d != saved_data_len %d",
874 x11_fake_data_len, x11_saved_data_len);
875 return -1;
876 }
877 /*
878 * Received authentication protocol and data match
879 * our fake data. Substitute the fake data with real
880 * data.
881 */
882 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
883 x11_saved_data, x11_saved_data_len);
884 return 1;
885 }
886
887 static void
888 channel_pre_x11_open_13(Channel *c, fd_set *readset, fd_set *writeset)
889 {
890 int ret = x11_open_helper(&c->output);
891
892 if (ret == 1) {
893 /* Start normal processing for the channel. */
894 c->type = SSH_CHANNEL_OPEN;
895 channel_pre_open_13(c, readset, writeset);
896 } else if (ret == -1) {
897 /*
898 * We have received an X11 connection that has bad
899 * authentication information.
900 */
901 logit("X11 connection rejected because of wrong authentication.");
902 buffer_clear(&c->input);
903 buffer_clear(&c->output);
904 channel_close_fd(&c->sock);
905 c->sock = -1;
906 c->type = SSH_CHANNEL_CLOSED;
907 packet_start(SSH_MSG_CHANNEL_CLOSE);
908 packet_put_int(c->remote_id);
909 packet_send();
910 }
911 }
912
913 static void
914 channel_pre_x11_open(Channel *c, fd_set *readset, fd_set *writeset)
915 {
916 int ret = x11_open_helper(&c->output);
917
918 /* c->force_drain = 1; */
919
920 if (ret == 1) {
921 c->type = SSH_CHANNEL_OPEN;
922 channel_pre_open(c, readset, writeset);
923 } else if (ret == -1) {
924 logit("X11 connection rejected because of wrong authentication.");
925 debug2("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
926 chan_read_failed(c);
927 buffer_clear(&c->input);
928 chan_ibuf_empty(c);
929 buffer_clear(&c->output);
930 /* for proto v1, the peer will send an IEOF */
931 if (compat20)
932 chan_write_failed(c);
933 else
934 c->type = SSH_CHANNEL_OPEN;
935 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
936 }
937 }
938
939 /* try to decode a socks4 header */
940 static int
941 channel_decode_socks4(Channel *c, fd_set *readset, fd_set *writeset)
942 {
943 char *p, *host;
944 u_int len, have, i, found;
945 char username[256];
946 struct {
947 u_int8_t version;
948 u_int8_t command;
949 u_int16_t dest_port;
950 struct in_addr dest_addr;
951 } s4_req, s4_rsp;
952
953 debug2("channel %d: decode socks4", c->self);
954
955 have = buffer_len(&c->input);
956 len = sizeof(s4_req);
957 if (have < len)
958 return 0;
959 p = buffer_ptr(&c->input);
960 for (found = 0, i = len; i < have; i++) {
961 if (p[i] == '\0') {
962 found = 1;
963 break;
964 }
965 if (i > 1024) {
966 /* the peer is probably sending garbage */
967 debug("channel %d: decode socks4: too long",
968 c->self);
969 return -1;
970 }
971 }
972 if (!found)
973 return 0;
974 buffer_get(&c->input, (char *)&s4_req.version, 1);
975 buffer_get(&c->input, (char *)&s4_req.command, 1);
976 buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
977 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
978 have = buffer_len(&c->input);
979 p = buffer_ptr(&c->input);
980 len = strlen(p);
981 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
982 if (len > have)
983 fatal("channel %d: decode socks4: len %d > have %d",
984 c->self, len, have);
985 strlcpy(username, p, sizeof(username));
986 buffer_consume(&c->input, len);
987 buffer_consume(&c->input, 1); /* trailing '\0' */
988
989 host = inet_ntoa(s4_req.dest_addr);
990 strlcpy(c->path, host, sizeof(c->path));
991 c->host_port = ntohs(s4_req.dest_port);
992
993 debug2("channel %d: dynamic request: socks4 host %s port %u command %u",
994 c->self, host, c->host_port, s4_req.command);
995
996 if (s4_req.command != 1) {
997 debug("channel %d: cannot handle: socks4 cn %d",
998 c->self, s4_req.command);
999 return -1;
1000 }
1001 s4_rsp.version = 0; /* vn: 0 for reply */
1002 s4_rsp.command = 90; /* cd: req granted */
1003 s4_rsp.dest_port = 0; /* ignored */
1004 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
1005 buffer_append(&c->output, &s4_rsp, sizeof(s4_rsp));
1006 return 1;
1007 }
1008
1009 /* try to decode a socks5 header */
1010 #define SSH_SOCKS5_AUTHDONE 0x1000
1011 #define SSH_SOCKS5_NOAUTH 0x00
1012 #define SSH_SOCKS5_IPV4 0x01
1013 #define SSH_SOCKS5_DOMAIN 0x03
1014 #define SSH_SOCKS5_IPV6 0x04
1015 #define SSH_SOCKS5_CONNECT 0x01
1016 #define SSH_SOCKS5_SUCCESS 0x00
1017
1018 static int
1019 channel_decode_socks5(Channel *c, fd_set *readset, fd_set *writeset)
1020 {
1021 struct {
1022 u_int8_t version;
1023 u_int8_t command;
1024 u_int8_t reserved;
1025 u_int8_t atyp;
1026 } s5_req, s5_rsp;
1027 u_int16_t dest_port;
1028 u_char *p, dest_addr[255+1];
1029 u_int have, need, i, found, nmethods, addrlen, af;
1030
1031 debug2("channel %d: decode socks5", c->self);
1032 p = buffer_ptr(&c->input);
1033 if (p[0] != 0x05)
1034 return -1;
1035 have = buffer_len(&c->input);
1036 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) {
1037 /* format: ver | nmethods | methods */
1038 if (have < 2)
1039 return 0;
1040 nmethods = p[1];
1041 if (have < nmethods + 2)
1042 return 0;
1043 /* look for method: "NO AUTHENTICATION REQUIRED" */
1044 for (found = 0, i = 2 ; i < nmethods + 2; i++) {
1045 if (p[i] == SSH_SOCKS5_NOAUTH ) {
1046 found = 1;
1047 break;
1048 }
1049 }
1050 if (!found) {
1051 debug("channel %d: method SSH_SOCKS5_NOAUTH not found",
1052 c->self);
1053 return -1;
1054 }
1055 buffer_consume(&c->input, nmethods + 2);
1056 buffer_put_char(&c->output, 0x05); /* version */
1057 buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH); /* method */
1058 FD_SET(c->sock, writeset);
1059 c->flags |= SSH_SOCKS5_AUTHDONE;
1060 debug2("channel %d: socks5 auth done", c->self);
1061 return 0; /* need more */
1062 }
1063 debug2("channel %d: socks5 post auth", c->self);
1064 if (have < sizeof(s5_req)+1)
1065 return 0; /* need more */
1066 memcpy(&s5_req, p, sizeof(s5_req));
1067 if (s5_req.version != 0x05 ||
1068 s5_req.command != SSH_SOCKS5_CONNECT ||
1069 s5_req.reserved != 0x00) {
1070 debug2("channel %d: only socks5 connect supported", c->self);
1071 return -1;
1072 }
1073 switch (s5_req.atyp){
1074 case SSH_SOCKS5_IPV4:
1075 addrlen = 4;
1076 af = AF_INET;
1077 break;
1078 case SSH_SOCKS5_DOMAIN:
1079 addrlen = p[sizeof(s5_req)];
1080 af = -1;
1081 break;
1082 case SSH_SOCKS5_IPV6:
1083 addrlen = 16;
1084 af = AF_INET6;
1085 break;
1086 default:
1087 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp);
1088 return -1;
1089 }
1090 need = sizeof(s5_req) + addrlen + 2;
1091 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1092 need++;
1093 if (have < need)
1094 return 0;
1095 buffer_consume(&c->input, sizeof(s5_req));
1096 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1097 buffer_consume(&c->input, 1); /* host string length */
1098 buffer_get(&c->input, (char *)&dest_addr, addrlen);
1099 buffer_get(&c->input, (char *)&dest_port, 2);
1100 dest_addr[addrlen] = '\0';
1101 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1102 strlcpy(c->path, (char *)dest_addr, sizeof(c->path));
1103 else if (inet_ntop(af, dest_addr, c->path, sizeof(c->path)) == NULL)
1104 return -1;
1105 c->host_port = ntohs(dest_port);
1106
1107 debug2("channel %d: dynamic request: socks5 host %s port %u command %u",
1108 c->self, c->path, c->host_port, s5_req.command);
1109
1110 s5_rsp.version = 0x05;
1111 s5_rsp.command = SSH_SOCKS5_SUCCESS;
1112 s5_rsp.reserved = 0; /* ignored */
1113 s5_rsp.atyp = SSH_SOCKS5_IPV4;
1114 ((struct in_addr *)&dest_addr)->s_addr = INADDR_ANY;
1115 dest_port = 0; /* ignored */
1116
1117 buffer_append(&c->output, &s5_rsp, sizeof(s5_rsp));
1118 buffer_append(&c->output, &dest_addr, sizeof(struct in_addr));
1119 buffer_append(&c->output, &dest_port, sizeof(dest_port));
1120 return 1;
1121 }
1122
1123 /* dynamic port forwarding */
1124 static void
1125 channel_pre_dynamic(Channel *c, fd_set *readset, fd_set *writeset)
1126 {
1127 u_char *p;
1128 u_int have;
1129 int ret;
1130
1131 have = buffer_len(&c->input);
1132 c->delayed = 0;
1133 debug2("channel %d: pre_dynamic: have %d", c->self, have);
1134 /* buffer_dump(&c->input); */
1135 /* check if the fixed size part of the packet is in buffer. */
1136 if (have < 3) {
1137 /* need more */
1138 FD_SET(c->sock, readset);
1139 return;
1140 }
1141 /* try to guess the protocol */
1142 p = buffer_ptr(&c->input);
1143 switch (p[0]) {
1144 case 0x04:
1145 ret = channel_decode_socks4(c, readset, writeset);
1146 break;
1147 case 0x05:
1148 ret = channel_decode_socks5(c, readset, writeset);
1149 break;
1150 default:
1151 ret = -1;
1152 break;
1153 }
1154 if (ret < 0) {
1155 chan_mark_dead(c);
1156 } else if (ret == 0) {
1157 debug2("channel %d: pre_dynamic: need more", c->self);
1158 /* need more */
1159 FD_SET(c->sock, readset);
1160 } else {
1161 /* switch to the next state */
1162 c->type = SSH_CHANNEL_OPENING;
1163 port_open_helper(c, "direct-tcpip");
1164 }
1165 }
1166
1167 /* This is our fake X11 server socket. */
1168 static void
1169 channel_post_x11_listener(Channel *c, fd_set *readset, fd_set *writeset)
1170 {
1171 Channel *nc;
1172 struct sockaddr addr;
1173 int newsock;
1174 socklen_t addrlen;
1175 char buf[16384], *remote_ipaddr;
1176 int remote_port;
1177
1178 if (FD_ISSET(c->sock, readset)) {
1179 debug("X11 connection requested.");
1180 addrlen = sizeof(addr);
1181 newsock = accept(c->sock, &addr, &addrlen);
1182 if (c->single_connection) {
1183 debug2("single_connection: closing X11 listener.");
1184 channel_close_fd(&c->sock);
1185 chan_mark_dead(c);
1186 }
1187 if (newsock < 0) {
1188 error("accept: %.100s", strerror(errno));
1189 return;
1190 }
1191 set_nodelay(newsock);
1192 remote_ipaddr = get_peer_ipaddr(newsock);
1193 remote_port = get_peer_port(newsock);
1194 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1195 remote_ipaddr, remote_port);
1196
1197 nc = channel_new("accepted x11 socket",
1198 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1199 c->local_window_max, c->local_maxpacket, 0, buf, 1);
1200 if (compat20) {
1201 packet_start(SSH2_MSG_CHANNEL_OPEN);
1202 packet_put_cstring("x11");
1203 packet_put_int(nc->self);
1204 packet_put_int(nc->local_window_max);
1205 packet_put_int(nc->local_maxpacket);
1206 /* originator ipaddr and port */
1207 packet_put_cstring(remote_ipaddr);
1208 if (datafellows & SSH_BUG_X11FWD) {
1209 debug2("ssh2 x11 bug compat mode");
1210 } else {
1211 packet_put_int(remote_port);
1212 }
1213 packet_send();
1214 } else {
1215 packet_start(SSH_SMSG_X11_OPEN);
1216 packet_put_int(nc->self);
1217 if (packet_get_protocol_flags() &
1218 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1219 packet_put_cstring(buf);
1220 packet_send();
1221 }
1222 xfree(remote_ipaddr);
1223 }
1224 }
1225
1226 static void
1227 port_open_helper(Channel *c, char *rtype)
1228 {
1229 int direct;
1230 char buf[1024];
1231 char *remote_ipaddr = get_peer_ipaddr(c->sock);
1232 int remote_port = get_peer_port(c->sock);
1233
1234 direct = (strcmp(rtype, "direct-tcpip") == 0);
1235
1236 snprintf(buf, sizeof buf,
1237 "%s: listening port %d for %.100s port %d, "
1238 "connect from %.200s port %d",
1239 rtype, c->listening_port, c->path, c->host_port,
1240 remote_ipaddr, remote_port);
1241
1242 xfree(c->remote_name);
1243 c->remote_name = xstrdup(buf);
1244
1245 if (compat20) {
1246 packet_start(SSH2_MSG_CHANNEL_OPEN);
1247 packet_put_cstring(rtype);
1248 packet_put_int(c->self);
1249 packet_put_int(c->local_window_max);
1250 packet_put_int(c->local_maxpacket);
1251 if (direct) {
1252 /* target host, port */
1253 packet_put_cstring(c->path);
1254 packet_put_int(c->host_port);
1255 } else {
1256 /* listen address, port */
1257 packet_put_cstring(c->path);
1258 packet_put_int(c->listening_port);
1259 }
1260 /* originator host and port */
1261 packet_put_cstring(remote_ipaddr);
1262 packet_put_int((u_int)remote_port);
1263 packet_send();
1264 } else {
1265 packet_start(SSH_MSG_PORT_OPEN);
1266 packet_put_int(c->self);
1267 packet_put_cstring(c->path);
1268 packet_put_int(c->host_port);
1269 if (packet_get_protocol_flags() &
1270 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1271 packet_put_cstring(c->remote_name);
1272 packet_send();
1273 }
1274 xfree(remote_ipaddr);
1275 }
1276
1277 static void
1278 channel_set_reuseaddr(int fd)
1279 {
1280 int on = 1;
1281
1282 /*
1283 * Set socket options.
1284 * Allow local port reuse in TIME_WAIT.
1285 */
1286 if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1)
1287 error("setsockopt SO_REUSEADDR fd %d: %s", fd, strerror(errno));
1288 }
1289
1290 /*
1291 * This socket is listening for connections to a forwarded TCP/IP port.
1292 */
1293 static void
1294 channel_post_port_listener(Channel *c, fd_set *readset, fd_set *writeset)
1295 {
1296 Channel *nc;
1297 struct sockaddr addr;
1298 int newsock, nextstate;
1299 socklen_t addrlen;
1300 char *rtype;
1301
1302 if (FD_ISSET(c->sock, readset)) {
1303 debug("Connection to port %d forwarding "
1304 "to %.100s port %d requested.",
1305 c->listening_port, c->path, c->host_port);
1306
1307 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1308 nextstate = SSH_CHANNEL_OPENING;
1309 rtype = "forwarded-tcpip";
1310 } else {
1311 if (c->host_port == 0) {
1312 nextstate = SSH_CHANNEL_DYNAMIC;
1313 rtype = "dynamic-tcpip";
1314 } else {
1315 nextstate = SSH_CHANNEL_OPENING;
1316 rtype = "direct-tcpip";
1317 }
1318 }
1319
1320 addrlen = sizeof(addr);
1321 newsock = accept(c->sock, &addr, &addrlen);
1322 if (newsock < 0) {
1323 error("accept: %.100s", strerror(errno));
1324 return;
1325 }
1326 set_nodelay(newsock);
1327 nc = channel_new(rtype, nextstate, newsock, newsock, -1,
1328 c->local_window_max, c->local_maxpacket, 0, rtype, 1);
1329 nc->listening_port = c->listening_port;
1330 nc->host_port = c->host_port;
1331 strlcpy(nc->path, c->path, sizeof(nc->path));
1332
1333 if (nextstate == SSH_CHANNEL_DYNAMIC) {
1334 /*
1335 * do not call the channel_post handler until
1336 * this flag has been reset by a pre-handler.
1337 * otherwise the FD_ISSET calls might overflow
1338 */
1339 nc->delayed = 1;
1340 } else {
1341 port_open_helper(nc, rtype);
1342 }
1343 }
1344 }
1345
1346 /*
1347 * This is the authentication agent socket listening for connections from
1348 * clients.
1349 */
1350 static void
1351 channel_post_auth_listener(Channel *c, fd_set *readset, fd_set *writeset)
1352 {
1353 Channel *nc;
1354 int newsock;
1355 struct sockaddr addr;
1356 socklen_t addrlen;
1357
1358 if (FD_ISSET(c->sock, readset)) {
1359 addrlen = sizeof(addr);
1360 newsock = accept(c->sock, &addr, &addrlen);
1361 if (newsock < 0) {
1362 error("accept from auth socket: %.100s", strerror(errno));
1363 return;
1364 }
1365 nc = channel_new("accepted auth socket",
1366 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1367 c->local_window_max, c->local_maxpacket,
1368 0, "accepted auth socket", 1);
1369 if (compat20) {
1370 packet_start(SSH2_MSG_CHANNEL_OPEN);
1371 packet_put_cstring("auth-agent@openssh.com");
1372 packet_put_int(nc->self);
1373 packet_put_int(c->local_window_max);
1374 packet_put_int(c->local_maxpacket);
1375 } else {
1376 packet_start(SSH_SMSG_AGENT_OPEN);
1377 packet_put_int(nc->self);
1378 }
1379 packet_send();
1380 }
1381 }
1382
1383 static void
1384 channel_post_connecting(Channel *c, fd_set *readset, fd_set *writeset)
1385 {
1386 int err = 0;
1387 socklen_t sz = sizeof(err);
1388
1389 if (FD_ISSET(c->sock, writeset)) {
1390 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) {
1391 err = errno;
1392 error("getsockopt SO_ERROR failed");
1393 }
1394 if (err == 0) {
1395 debug("channel %d: connected", c->self);
1396 c->type = SSH_CHANNEL_OPEN;
1397 if (compat20) {
1398 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1399 packet_put_int(c->remote_id);
1400 packet_put_int(c->self);
1401 packet_put_int(c->local_window);
1402 packet_put_int(c->local_maxpacket);
1403 } else {
1404 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1405 packet_put_int(c->remote_id);
1406 packet_put_int(c->self);
1407 }
1408 } else {
1409 debug("channel %d: not connected: %s",
1410 c->self, strerror(err));
1411 if (compat20) {
1412 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1413 packet_put_int(c->remote_id);
1414 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1415 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1416 packet_put_cstring(strerror(err));
1417 packet_put_cstring("");
1418 }
1419 } else {
1420 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1421 packet_put_int(c->remote_id);
1422 }
1423 chan_mark_dead(c);
1424 }
1425 packet_send();
1426 }
1427 }
1428
1429 static int
1430 channel_handle_rfd(Channel *c, fd_set *readset, fd_set *writeset)
1431 {
1432 char buf[CHAN_RBUF];
1433 int len;
1434
1435 if (c->rfd != -1 &&
1436 FD_ISSET(c->rfd, readset)) {
1437 errno = 0;
1438 len = read(c->rfd, buf, sizeof(buf));
1439 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1440 return 1;
1441 #ifndef PTY_ZEROREAD
1442 if (len <= 0) {
1443 #else
1444 if ((!c->isatty && len <= 0) ||
1445 (c->isatty && (len < 0 || (len == 0 && errno != 0)))) {
1446 #endif
1447 debug2("channel %d: read<=0 rfd %d len %d",
1448 c->self, c->rfd, len);
1449 if (c->type != SSH_CHANNEL_OPEN) {
1450 debug2("channel %d: not open", c->self);
1451 chan_mark_dead(c);
1452 return -1;
1453 } else if (compat13) {
1454 buffer_clear(&c->output);
1455 c->type = SSH_CHANNEL_INPUT_DRAINING;
1456 debug2("channel %d: input draining.", c->self);
1457 } else {
1458 chan_read_failed(c);
1459 }
1460 return -1;
1461 }
1462 if (c->input_filter != NULL) {
1463 if (c->input_filter(c, buf, len) == -1) {
1464 debug2("channel %d: filter stops", c->self);
1465 chan_read_failed(c);
1466 }
1467 } else if (c->datagram) {
1468 buffer_put_string(&c->input, buf, len);
1469 } else {
1470 buffer_append(&c->input, buf, len);
1471 }
1472 }
1473 return 1;
1474 }
1475
1476 static int
1477 channel_handle_wfd(Channel *c, fd_set *readset, fd_set *writeset)
1478 {
1479 struct termios tio;
1480 u_char *data = NULL, *buf;
1481 u_int dlen;
1482 int len;
1483
1484 /* Send buffered output data to the socket. */
1485 if (c->wfd != -1 &&
1486 FD_ISSET(c->wfd, writeset) &&
1487 buffer_len(&c->output) > 0) {
1488 if (c->output_filter != NULL) {
1489 if ((buf = c->output_filter(c, &data, &dlen)) == NULL) {
1490 debug2("channel %d: filter stops", c->self);
1491 if (c->type != SSH_CHANNEL_OPEN)
1492 chan_mark_dead(c);
1493 else
1494 chan_write_failed(c);
1495 return -1;
1496 }
1497 } else if (c->datagram) {
1498 buf = data = buffer_get_string(&c->output, &dlen);
1499 } else {
1500 buf = data = buffer_ptr(&c->output);
1501 dlen = buffer_len(&c->output);
1502 }
1503
1504 if (c->datagram) {
1505 /* ignore truncated writes, datagrams might get lost */
1506 c->local_consumed += dlen + 4;
1507 len = write(c->wfd, buf, dlen);
1508 xfree(data);
1509 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1510 return 1;
1511 if (len <= 0) {
1512 if (c->type != SSH_CHANNEL_OPEN)
1513 chan_mark_dead(c);
1514 else
1515 chan_write_failed(c);
1516 return -1;
1517 }
1518 return 1;
1519 }
1520 #ifdef _AIX
1521 /* XXX: Later AIX versions can't push as much data to tty */
1522 if (compat20 && c->wfd_isatty)
1523 dlen = MIN(dlen, 8*1024);
1524 #endif
1525
1526 len = write(c->wfd, buf, dlen);
1527 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1528 return 1;
1529 if (len <= 0) {
1530 if (c->type != SSH_CHANNEL_OPEN) {
1531 debug2("channel %d: not open", c->self);
1532 chan_mark_dead(c);
1533 return -1;
1534 } else if (compat13) {
1535 buffer_clear(&c->output);
1536 debug2("channel %d: input draining.", c->self);
1537 c->type = SSH_CHANNEL_INPUT_DRAINING;
1538 } else {
1539 chan_write_failed(c);
1540 }
1541 return -1;
1542 }
1543 if (compat20 && c->isatty && dlen >= 1 && buf[0] != '\r') {
1544 if (tcgetattr(c->wfd, &tio) == 0 &&
1545 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1546 /*
1547 * Simulate echo to reduce the impact of
1548 * traffic analysis. We need to match the
1549 * size of a SSH2_MSG_CHANNEL_DATA message
1550 * (4 byte channel id + buf)
1551 */
1552 packet_send_ignore(4 + len);
1553 packet_send();
1554 }
1555 }
1556 buffer_consume(&c->output, len);
1557 if (compat20 && len > 0) {
1558 c->local_consumed += len;
1559 }
1560 }
1561 return 1;
1562 }
1563
1564 static int
1565 channel_handle_efd(Channel *c, fd_set *readset, fd_set *writeset)
1566 {
1567 char buf[CHAN_RBUF];
1568 int len;
1569
1570 /** XXX handle drain efd, too */
1571 if (c->efd != -1) {
1572 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1573 FD_ISSET(c->efd, writeset) &&
1574 buffer_len(&c->extended) > 0) {
1575 len = write(c->efd, buffer_ptr(&c->extended),
1576 buffer_len(&c->extended));
1577 debug2("channel %d: written %d to efd %d",
1578 c->self, len, c->efd);
1579 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1580 return 1;
1581 if (len <= 0) {
1582 debug2("channel %d: closing write-efd %d",
1583 c->self, c->efd);
1584 channel_close_fd(&c->efd);
1585 } else {
1586 buffer_consume(&c->extended, len);
1587 c->local_consumed += len;
1588 }
1589 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
1590 FD_ISSET(c->efd, readset)) {
1591 len = read(c->efd, buf, sizeof(buf));
1592 debug2("channel %d: read %d from efd %d",
1593 c->self, len, c->efd);
1594 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1595 return 1;
1596 if (len <= 0) {
1597 debug2("channel %d: closing read-efd %d",
1598 c->self, c->efd);
1599 channel_close_fd(&c->efd);
1600 } else {
1601 buffer_append(&c->extended, buf, len);
1602 }
1603 }
1604 }
1605 return 1;
1606 }
1607
1608 static int
1609 channel_handle_ctl(Channel *c, fd_set *readset, fd_set *writeset)
1610 {
1611 char buf[16];
1612 int len;
1613
1614 /* Monitor control fd to detect if the slave client exits */
1615 if (c->ctl_fd != -1 && FD_ISSET(c->ctl_fd, readset)) {
1616 len = read(c->ctl_fd, buf, sizeof(buf));
1617 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1618 return 1;
1619 if (len <= 0) {
1620 debug2("channel %d: ctl read<=0", c->self);
1621 if (c->type != SSH_CHANNEL_OPEN) {
1622 debug2("channel %d: not open", c->self);
1623 chan_mark_dead(c);
1624 return -1;
1625 } else {
1626 chan_read_failed(c);
1627 chan_write_failed(c);
1628 }
1629 return -1;
1630 } else
1631 fatal("%s: unexpected data on ctl fd", __func__);
1632 }
1633 return 1;
1634 }
1635
1636 static int
1637 channel_check_window(Channel *c)
1638 {
1639 if (c->type == SSH_CHANNEL_OPEN &&
1640 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1641 c->local_window < c->local_window_max/2 &&
1642 c->local_consumed > 0) {
1643 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1644 packet_put_int(c->remote_id);
1645 packet_put_int(c->local_consumed);
1646 packet_send();
1647 debug2("channel %d: window %d sent adjust %d",
1648 c->self, c->local_window,
1649 c->local_consumed);
1650 c->local_window += c->local_consumed;
1651 c->local_consumed = 0;
1652 }
1653 return 1;
1654 }
1655
1656 static void
1657 channel_post_open(Channel *c, fd_set *readset, fd_set *writeset)
1658 {
1659 if (c->delayed)
1660 return;
1661 channel_handle_rfd(c, readset, writeset);
1662 channel_handle_wfd(c, readset, writeset);
1663 if (!compat20)
1664 return;
1665 channel_handle_efd(c, readset, writeset);
1666 channel_handle_ctl(c, readset, writeset);
1667 channel_check_window(c);
1668 }
1669
1670 static void
1671 channel_post_output_drain_13(Channel *c, fd_set *readset, fd_set *writeset)
1672 {
1673 int len;
1674
1675 /* Send buffered output data to the socket. */
1676 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1677 len = write(c->sock, buffer_ptr(&c->output),
1678 buffer_len(&c->output));
1679 if (len <= 0)
1680 buffer_clear(&c->output);
1681 else
1682 buffer_consume(&c->output, len);
1683 }
1684 }
1685
1686 static void
1687 channel_handler_init_20(void)
1688 {
1689 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1690 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1691 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1692 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
1693 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1694 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1695 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1696 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1697
1698 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1699 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1700 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
1701 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1702 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1703 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1704 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1705 }
1706
1707 static void
1708 channel_handler_init_13(void)
1709 {
1710 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
1711 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
1712 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1713 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1714 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1715 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
1716 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1717 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1718 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1719
1720 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1721 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1722 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1723 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1724 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
1725 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1726 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1727 }
1728
1729 static void
1730 channel_handler_init_15(void)
1731 {
1732 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1733 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1734 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1735 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1736 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1737 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1738 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1739
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_OPEN] = &channel_post_open;
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(void)
1750 {
1751 int i;
1752
1753 for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
1754 channel_pre[i] = NULL;
1755 channel_post[i] = NULL;
1756 }
1757 if (compat20)
1758 channel_handler_init_20();
1759 else if (compat13)
1760 channel_handler_init_13();
1761 else
1762 channel_handler_init_15();
1763 }
1764
1765 /* gc dead channels */
1766 static void
1767 channel_garbage_collect(Channel *c)
1768 {
1769 if (c == NULL)
1770 return;
1771 if (c->detach_user != NULL) {
1772 if (!chan_is_dead(c, c->detach_close))
1773 return;
1774 debug2("channel %d: gc: notify user", c->self);
1775 c->detach_user(c->self, NULL);
1776 /* if we still have a callback */
1777 if (c->detach_user != NULL)
1778 return;
1779 debug2("channel %d: gc: user detached", c->self);
1780 }
1781 if (!chan_is_dead(c, 1))
1782 return;
1783 debug2("channel %d: garbage collecting", c->self);
1784 channel_free(c);
1785 }
1786
1787 static void
1788 channel_handler(chan_fn *ftab[], fd_set *readset, fd_set *writeset)
1789 {
1790 static int did_init = 0;
1791 u_int i;
1792 Channel *c;
1793
1794 if (!did_init) {
1795 channel_handler_init();
1796 did_init = 1;
1797 }
1798 for (i = 0; i < channels_alloc; i++) {
1799 c = channels[i];
1800 if (c == NULL)
1801 continue;
1802 if (ftab[c->type] != NULL)
1803 (*ftab[c->type])(c, readset, writeset);
1804 channel_garbage_collect(c);
1805 }
1806 }
1807
1808 /*
1809 * Allocate/update select bitmasks and add any bits relevant to channels in
1810 * select bitmasks.
1811 */
1812 void
1813 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
1814 u_int *nallocp, int rekeying)
1815 {
1816 u_int n, sz, nfdset;
1817
1818 n = MAX(*maxfdp, channel_max_fd);
1819
1820 nfdset = howmany(n+1, NFDBITS);
1821 /* Explicitly test here, because xrealloc isn't always called */
1822 if (nfdset && SIZE_T_MAX / nfdset < sizeof(fd_mask))
1823 fatal("channel_prepare_select: max_fd (%d) is too large", n);
1824 sz = nfdset * sizeof(fd_mask);
1825
1826 /* perhaps check sz < nalloc/2 and shrink? */
1827 if (*readsetp == NULL || sz > *nallocp) {
1828 *readsetp = xrealloc(*readsetp, nfdset, sizeof(fd_mask));
1829 *writesetp = xrealloc(*writesetp, nfdset, sizeof(fd_mask));
1830 *nallocp = sz;
1831 }
1832 *maxfdp = n;
1833 memset(*readsetp, 0, sz);
1834 memset(*writesetp, 0, sz);
1835
1836 if (!rekeying)
1837 channel_handler(channel_pre, *readsetp, *writesetp);
1838 }
1839
1840 /*
1841 * After select, perform any appropriate operations for channels which have
1842 * events pending.
1843 */
1844 void
1845 channel_after_select(fd_set *readset, fd_set *writeset)
1846 {
1847 channel_handler(channel_post, readset, writeset);
1848 }
1849
1850
1851 /* If there is data to send to the connection, enqueue some of it now. */
1852 void
1853 channel_output_poll(void)
1854 {
1855 Channel *c;
1856 u_int i, len;
1857
1858 for (i = 0; i < channels_alloc; i++) {
1859 c = channels[i];
1860 if (c == NULL)
1861 continue;
1862
1863 /*
1864 * We are only interested in channels that can have buffered
1865 * incoming data.
1866 */
1867 if (compat13) {
1868 if (c->type != SSH_CHANNEL_OPEN &&
1869 c->type != SSH_CHANNEL_INPUT_DRAINING)
1870 continue;
1871 } else {
1872 if (c->type != SSH_CHANNEL_OPEN)
1873 continue;
1874 }
1875 if (compat20 &&
1876 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
1877 /* XXX is this true? */
1878 debug3("channel %d: will not send data after close", c->self);
1879 continue;
1880 }
1881
1882 /* Get the amount of buffered data for this channel. */
1883 if ((c->istate == CHAN_INPUT_OPEN ||
1884 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
1885 (len = buffer_len(&c->input)) > 0) {
1886 if (c->datagram) {
1887 if (len > 0) {
1888 u_char *data;
1889 u_int dlen;
1890
1891 data = buffer_get_string(&c->input,
1892 &dlen);
1893 packet_start(SSH2_MSG_CHANNEL_DATA);
1894 packet_put_int(c->remote_id);
1895 packet_put_string(data, dlen);
1896 packet_send();
1897 c->remote_window -= dlen + 4;
1898 xfree(data);
1899 }
1900 continue;
1901 }
1902 /*
1903 * Send some data for the other side over the secure
1904 * connection.
1905 */
1906 if (compat20) {
1907 if (len > c->remote_window)
1908 len = c->remote_window;
1909 if (len > c->remote_maxpacket)
1910 len = c->remote_maxpacket;
1911 } else {
1912 if (packet_is_interactive()) {
1913 if (len > 1024)
1914 len = 512;
1915 } else {
1916 /* Keep the packets at reasonable size. */
1917 if (len > packet_get_maxsize()/2)
1918 len = packet_get_maxsize()/2;
1919 }
1920 }
1921 if (len > 0) {
1922 packet_start(compat20 ?
1923 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
1924 packet_put_int(c->remote_id);
1925 packet_put_string(buffer_ptr(&c->input), len);
1926 packet_send();
1927 buffer_consume(&c->input, len);
1928 c->remote_window -= len;
1929 }
1930 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1931 if (compat13)
1932 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
1933 /*
1934 * input-buffer is empty and read-socket shutdown:
1935 * tell peer, that we will not send more data: send IEOF.
1936 * hack for extended data: delay EOF if EFD still in use.
1937 */
1938 if (CHANNEL_EFD_INPUT_ACTIVE(c))
1939 debug2("channel %d: ibuf_empty delayed efd %d/(%d)",
1940 c->self, c->efd, buffer_len(&c->extended));
1941 else
1942 chan_ibuf_empty(c);
1943 }
1944 /* Send extended data, i.e. stderr */
1945 if (compat20 &&
1946 !(c->flags & CHAN_EOF_SENT) &&
1947 c->remote_window > 0 &&
1948 (len = buffer_len(&c->extended)) > 0 &&
1949 c->extended_usage == CHAN_EXTENDED_READ) {
1950 debug2("channel %d: rwin %u elen %u euse %d",
1951 c->self, c->remote_window, buffer_len(&c->extended),
1952 c->extended_usage);
1953 if (len > c->remote_window)
1954 len = c->remote_window;
1955 if (len > c->remote_maxpacket)
1956 len = c->remote_maxpacket;
1957 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
1958 packet_put_int(c->remote_id);
1959 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
1960 packet_put_string(buffer_ptr(&c->extended), len);
1961 packet_send();
1962 buffer_consume(&c->extended, len);
1963 c->remote_window -= len;
1964 debug2("channel %d: sent ext data %d", c->self, len);
1965 }
1966 }
1967 }
1968
1969
1970 /* -- protocol input */
1971
1972 /* ARGSUSED */
1973 void
1974 channel_input_data(int type, u_int32_t seq, void *ctxt)
1975 {
1976 int id;
1977 char *data;
1978 u_int data_len;
1979 Channel *c;
1980
1981 /* Get the channel number and verify it. */
1982 id = packet_get_int();
1983 c = channel_lookup(id);
1984 if (c == NULL)
1985 packet_disconnect("Received data for nonexistent channel %d.", id);
1986
1987 /* Ignore any data for non-open channels (might happen on close) */
1988 if (c->type != SSH_CHANNEL_OPEN &&
1989 c->type != SSH_CHANNEL_X11_OPEN)
1990 return;
1991
1992 /* Get the data. */
1993 data = packet_get_string(&data_len);
1994
1995 /*
1996 * Ignore data for protocol > 1.3 if output end is no longer open.
1997 * For protocol 2 the sending side is reducing its window as it sends
1998 * data, so we must 'fake' consumption of the data in order to ensure
1999 * that window updates are sent back. Otherwise the connection might
2000 * deadlock.
2001 */
2002 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) {
2003 if (compat20) {
2004 c->local_window -= data_len;
2005 c->local_consumed += data_len;
2006 }
2007 xfree(data);
2008 return;
2009 }
2010
2011 if (compat20) {
2012 if (data_len > c->local_maxpacket) {
2013 logit("channel %d: rcvd big packet %d, maxpack %d",
2014 c->self, data_len, c->local_maxpacket);
2015 }
2016 if (data_len > c->local_window) {
2017 logit("channel %d: rcvd too much data %d, win %d",
2018 c->self, data_len, c->local_window);
2019 xfree(data);
2020 return;
2021 }
2022 c->local_window -= data_len;
2023 }
2024 packet_check_eom();
2025 if (c->datagram)
2026 buffer_put_string(&c->output, data, data_len);
2027 else
2028 buffer_append(&c->output, data, data_len);
2029 xfree(data);
2030 }
2031
2032 /* ARGSUSED */
2033 void
2034 channel_input_extended_data(int type, u_int32_t seq, void *ctxt)
2035 {
2036 int id;
2037 char *data;
2038 u_int data_len, tcode;
2039 Channel *c;
2040
2041 /* Get the channel number and verify it. */
2042 id = packet_get_int();
2043 c = channel_lookup(id);
2044
2045 if (c == NULL)
2046 packet_disconnect("Received extended_data for bad channel %d.", id);
2047 if (c->type != SSH_CHANNEL_OPEN) {
2048 logit("channel %d: ext data for non open", id);
2049 return;
2050 }
2051 if (c->flags & CHAN_EOF_RCVD) {
2052 if (datafellows & SSH_BUG_EXTEOF)
2053 debug("channel %d: accepting ext data after eof", id);
2054 else
2055 packet_disconnect("Received extended_data after EOF "
2056 "on channel %d.", id);
2057 }
2058 tcode = packet_get_int();
2059 if (c->efd == -1 ||
2060 c->extended_usage != CHAN_EXTENDED_WRITE ||
2061 tcode != SSH2_EXTENDED_DATA_STDERR) {
2062 logit("channel %d: bad ext data", c->self);
2063 return;
2064 }
2065 data = packet_get_string(&data_len);
2066 packet_check_eom();
2067 if (data_len > c->local_window) {
2068 logit("channel %d: rcvd too much extended_data %d, win %d",
2069 c->self, data_len, c->local_window);
2070 xfree(data);
2071 return;
2072 }
2073 debug2("channel %d: rcvd ext data %d", c->self, data_len);
2074 c->local_window -= data_len;
2075 buffer_append(&c->extended, data, data_len);
2076 xfree(data);
2077 }
2078
2079 /* ARGSUSED */
2080 void
2081 channel_input_ieof(int type, u_int32_t seq, void *ctxt)
2082 {
2083 int id;
2084 Channel *c;
2085
2086 id = packet_get_int();
2087 packet_check_eom();
2088 c = channel_lookup(id);
2089 if (c == NULL)
2090 packet_disconnect("Received ieof for nonexistent channel %d.", id);
2091 chan_rcvd_ieof(c);
2092
2093 /* XXX force input close */
2094 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) {
2095 debug("channel %d: FORCE input drain", c->self);
2096 c->istate = CHAN_INPUT_WAIT_DRAIN;
2097 if (buffer_len(&c->input) == 0)
2098 chan_ibuf_empty(c);
2099 }
2100
2101 }
2102
2103 /* ARGSUSED */
2104 void
2105 channel_input_close(int type, u_int32_t seq, void *ctxt)
2106 {
2107 int id;
2108 Channel *c;
2109
2110 id = packet_get_int();
2111 packet_check_eom();
2112 c = channel_lookup(id);
2113 if (c == NULL)
2114 packet_disconnect("Received close for nonexistent channel %d.", id);
2115
2116 /*
2117 * Send a confirmation that we have closed the channel and no more
2118 * data is coming for it.
2119 */
2120 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
2121 packet_put_int(c->remote_id);
2122 packet_send();
2123
2124 /*
2125 * If the channel is in closed state, we have sent a close request,
2126 * and the other side will eventually respond with a confirmation.
2127 * Thus, we cannot free the channel here, because then there would be
2128 * no-one to receive the confirmation. The channel gets freed when
2129 * the confirmation arrives.
2130 */
2131 if (c->type != SSH_CHANNEL_CLOSED) {
2132 /*
2133 * Not a closed channel - mark it as draining, which will
2134 * cause it to be freed later.
2135 */
2136 buffer_clear(&c->input);
2137 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
2138 }
2139 }
2140
2141 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
2142 /* ARGSUSED */
2143 void
2144 channel_input_oclose(int type, u_int32_t seq, void *ctxt)
2145 {
2146 int id = packet_get_int();
2147 Channel *c = channel_lookup(id);
2148
2149 packet_check_eom();
2150 if (c == NULL)
2151 packet_disconnect("Received oclose for nonexistent channel %d.", id);
2152 chan_rcvd_oclose(c);
2153 }
2154
2155 /* ARGSUSED */
2156 void
2157 channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt)
2158 {
2159 int id = packet_get_int();
2160 Channel *c = channel_lookup(id);
2161
2162 packet_check_eom();
2163 if (c == NULL)
2164 packet_disconnect("Received close confirmation for "
2165 "out-of-range channel %d.", id);
2166 if (c->type != SSH_CHANNEL_CLOSED)
2167 packet_disconnect("Received close confirmation for "
2168 "non-closed channel %d (type %d).", id, c->type);
2169 channel_free(c);
2170 }
2171
2172 /* ARGSUSED */
2173 void
2174 channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt)
2175 {
2176 int id, remote_id;
2177 Channel *c;
2178
2179 id = packet_get_int();
2180 c = channel_lookup(id);
2181
2182 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2183 packet_disconnect("Received open confirmation for "
2184 "non-opening channel %d.", id);
2185 remote_id = packet_get_int();
2186 /* Record the remote channel number and mark that the channel is now open. */
2187 c->remote_id = remote_id;
2188 c->type = SSH_CHANNEL_OPEN;
2189
2190 if (compat20) {
2191 c->remote_window = packet_get_int();
2192 c->remote_maxpacket = packet_get_int();
2193 if (c->confirm) {
2194 debug2("callback start");
2195 c->confirm(c->self, c->confirm_ctx);
2196 debug2("callback done");
2197 }
2198 debug2("channel %d: open confirm rwindow %u rmax %u", c->self,
2199 c->remote_window, c->remote_maxpacket);
2200 }
2201 packet_check_eom();
2202 }
2203
2204 static char *
2205 reason2txt(int reason)
2206 {
2207 switch (reason) {
2208 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
2209 return "administratively prohibited";
2210 case SSH2_OPEN_CONNECT_FAILED:
2211 return "connect failed";
2212 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
2213 return "unknown channel type";
2214 case SSH2_OPEN_RESOURCE_SHORTAGE:
2215 return "resource shortage";
2216 }
2217 return "unknown reason";
2218 }
2219
2220 /* ARGSUSED */
2221 void
2222 channel_input_open_failure(int type, u_int32_t seq, void *ctxt)
2223 {
2224 int id, reason;
2225 char *msg = NULL, *lang = NULL;
2226 Channel *c;
2227
2228 id = packet_get_int();
2229 c = channel_lookup(id);
2230
2231 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2232 packet_disconnect("Received open failure for "
2233 "non-opening channel %d.", id);
2234 if (compat20) {
2235 reason = packet_get_int();
2236 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
2237 msg = packet_get_string(NULL);
2238 lang = packet_get_string(NULL);
2239 }
2240 logit("channel %d: open failed: %s%s%s", id,
2241 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
2242 if (msg != NULL)
2243 xfree(msg);
2244 if (lang != NULL)
2245 xfree(lang);
2246 }
2247 packet_check_eom();
2248 /* Free the channel. This will also close the socket. */
2249 channel_free(c);
2250 }
2251
2252 /* ARGSUSED */
2253 void
2254 channel_input_window_adjust(int type, u_int32_t seq, void *ctxt)
2255 {
2256 Channel *c;
2257 int id;
2258 u_int adjust;
2259
2260 if (!compat20)
2261 return;
2262
2263 /* Get the channel number and verify it. */
2264 id = packet_get_int();
2265 c = channel_lookup(id);
2266
2267 if (c == NULL) {
2268 logit("Received window adjust for non-open channel %d.", id);
2269 return;
2270 }
2271 adjust = packet_get_int();
2272 packet_check_eom();
2273 debug2("channel %d: rcvd adjust %u", id, adjust);
2274 c->remote_window += adjust;
2275 }
2276
2277 /* ARGSUSED */
2278 void
2279 channel_input_port_open(int type, u_int32_t seq, void *ctxt)
2280 {
2281 Channel *c = NULL;
2282 u_short host_port;
2283 char *host, *originator_string;
2284 int remote_id, sock = -1;
2285
2286 remote_id = packet_get_int();
2287 host = packet_get_string(NULL);
2288 host_port = packet_get_int();
2289
2290 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2291 originator_string = packet_get_string(NULL);
2292 } else {
2293 originator_string = xstrdup("unknown (remote did not supply name)");
2294 }
2295 packet_check_eom();
2296 sock = channel_connect_to(host, host_port);
2297 if (sock != -1) {
2298 c = channel_new("connected socket",
2299 SSH_CHANNEL_CONNECTING, sock, sock, -1, 0, 0, 0,
2300 originator_string, 1);
2301 c->remote_id = remote_id;
2302 }
2303 xfree(originator_string);
2304 if (c == NULL) {
2305 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2306 packet_put_int(remote_id);
2307 packet_send();
2308 }
2309 xfree(host);
2310 }
2311
2312
2313 /* -- tcp forwarding */
2314
2315 void
2316 channel_set_af(int af)
2317 {
2318 IPv4or6 = af;
2319 }
2320
2321 static int
2322 channel_setup_fwd_listener(int type, const char *listen_addr, u_short listen_port,
2323 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2324 {
2325 Channel *c;
2326 int sock, r, success = 0, wildcard = 0, is_client;
2327 struct addrinfo hints, *ai, *aitop;
2328 const char *host, *addr;
2329 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2330
2331 host = (type == SSH_CHANNEL_RPORT_LISTENER) ?
2332 listen_addr : host_to_connect;
2333 is_client = (type == SSH_CHANNEL_PORT_LISTENER);
2334
2335 if (host == NULL) {
2336 error("No forward host name.");
2337 return 0;
2338 }
2339 if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) {
2340 error("Forward host name too long.");
2341 return 0;
2342 }
2343
2344 /*
2345 * Determine whether or not a port forward listens to loopback,
2346 * specified address or wildcard. On the client, a specified bind
2347 * address will always override gateway_ports. On the server, a
2348 * gateway_ports of 1 (``yes'') will override the client's
2349 * specification and force a wildcard bind, whereas a value of 2
2350 * (``clientspecified'') will bind to whatever address the client
2351 * asked for.
2352 *
2353 * Special-case listen_addrs are:
2354 *
2355 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR
2356 * "" (empty string), "*" -> wildcard v4/v6
2357 * "localhost" -> loopback v4/v6
2358 */
2359 addr = NULL;
2360 if (listen_addr == NULL) {
2361 /* No address specified: default to gateway_ports setting */
2362 if (gateway_ports)
2363 wildcard = 1;
2364 } else if (gateway_ports || is_client) {
2365 if (((datafellows & SSH_OLD_FORWARD_ADDR) &&
2366 strcmp(listen_addr, "0.0.0.0") == 0) ||
2367 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 ||
2368 (!is_client && gateway_ports == 1))
2369 wildcard = 1;
2370 else if (strcmp(listen_addr, "localhost") != 0)
2371 addr = listen_addr;
2372 }
2373
2374 debug3("channel_setup_fwd_listener: type %d wildcard %d addr %s",
2375 type, wildcard, (addr == NULL) ? "NULL" : addr);
2376
2377 /*
2378 * getaddrinfo returns a loopback address if the hostname is
2379 * set to NULL and hints.ai_flags is not AI_PASSIVE
2380 */
2381 memset(&hints, 0, sizeof(hints));
2382 hints.ai_family = IPv4or6;
2383 hints.ai_flags = wildcard ? AI_PASSIVE : 0;
2384 hints.ai_socktype = SOCK_STREAM;
2385 snprintf(strport, sizeof strport, "%d", listen_port);
2386 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) {
2387 if (addr == NULL) {
2388 /* This really shouldn't happen */
2389 packet_disconnect("getaddrinfo: fatal error: %s",
2390 gai_strerror(r));
2391 } else {
2392 error("channel_setup_fwd_listener: "
2393 "getaddrinfo(%.64s): %s", addr, gai_strerror(r));
2394 }
2395 return 0;
2396 }
2397
2398 for (ai = aitop; ai; ai = ai->ai_next) {
2399 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2400 continue;
2401 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2402 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2403 error("channel_setup_fwd_listener: getnameinfo failed");
2404 continue;
2405 }
2406 /* Create a port to listen for the host. */
2407 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2408 if (sock < 0) {
2409 /* this is no error since kernel may not support ipv6 */
2410 verbose("socket: %.100s", strerror(errno));
2411 continue;
2412 }
2413
2414 channel_set_reuseaddr(sock);
2415
2416 debug("Local forwarding listening on %s port %s.", ntop, strport);
2417
2418 /* Bind the socket to the address. */
2419 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2420 /* address can be in use ipv6 address is already bound */
2421 if (!ai->ai_next)
2422 error("bind: %.100s", strerror(errno));
2423 else
2424 verbose("bind: %.100s", strerror(errno));
2425
2426 close(sock);
2427 continue;
2428 }
2429 /* Start listening for connections on the socket. */
2430 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2431 error("listen: %.100s", strerror(errno));
2432 close(sock);
2433 continue;
2434 }
2435 /* Allocate a channel number for the socket. */
2436 c = channel_new("port listener", type, sock, sock, -1,
2437 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2438 0, "port listener", 1);
2439 strlcpy(c->path, host, sizeof(c->path));
2440 c->host_port = port_to_connect;
2441 c->listening_port = listen_port;
2442 success = 1;
2443 }
2444 if (success == 0)
2445 error("channel_setup_fwd_listener: cannot listen to port: %d",
2446 listen_port);
2447 freeaddrinfo(aitop);
2448 return success;
2449 }
2450
2451 int
2452 channel_cancel_rport_listener(const char *host, u_short port)
2453 {
2454 u_int i;
2455 int found = 0;
2456
2457 for (i = 0; i < channels_alloc; i++) {
2458 Channel *c = channels[i];
2459
2460 if (c != NULL && c->type == SSH_CHANNEL_RPORT_LISTENER &&
2461 strncmp(c->path, host, sizeof(c->path)) == 0 &&
2462 c->listening_port == port) {
2463 debug2("%s: close channel %d", __func__, i);
2464 channel_free(c);
2465 found = 1;
2466 }
2467 }
2468
2469 return (found);
2470 }
2471
2472 /* protocol local port fwd, used by ssh (and sshd in v1) */
2473 int
2474 channel_setup_local_fwd_listener(const char *listen_host, u_short listen_port,
2475 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2476 {
2477 return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER,
2478 listen_host, listen_port, host_to_connect, port_to_connect,
2479 gateway_ports);
2480 }
2481
2482 /* protocol v2 remote port fwd, used by sshd */
2483 int
2484 channel_setup_remote_fwd_listener(const char *listen_address,
2485 u_short listen_port, int gateway_ports)
2486 {
2487 return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER,
2488 listen_address, listen_port, NULL, 0, gateway_ports);
2489 }
2490
2491 /*
2492 * Initiate forwarding of connections to port "port" on remote host through
2493 * the secure channel to host:port from local side.
2494 */
2495
2496 int
2497 channel_request_remote_forwarding(const char *listen_host, u_short listen_port,
2498 const char *host_to_connect, u_short port_to_connect)
2499 {
2500 int type, success = 0;
2501
2502 /* Record locally that connection to this host/port is permitted. */
2503 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2504 fatal("channel_request_remote_forwarding: too many forwards");
2505
2506 /* Send the forward request to the remote side. */
2507 if (compat20) {
2508 const char *address_to_bind;
2509 if (listen_host == NULL)
2510 address_to_bind = "localhost";
2511 else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0)
2512 address_to_bind = "";
2513 else
2514 address_to_bind = listen_host;
2515
2516 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2517 packet_put_cstring("tcpip-forward");
2518 packet_put_char(1); /* boolean: want reply */
2519 packet_put_cstring(address_to_bind);
2520 packet_put_int(listen_port);
2521 packet_send();
2522 packet_write_wait();
2523 /* Assume that server accepts the request */
2524 success = 1;
2525 } else {
2526 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2527 packet_put_int(listen_port);
2528 packet_put_cstring(host_to_connect);
2529 packet_put_int(port_to_connect);
2530 packet_send();
2531 packet_write_wait();
2532
2533 /* Wait for response from the remote side. */
2534 type = packet_read();
2535 switch (type) {
2536 case SSH_SMSG_SUCCESS:
2537 success = 1;
2538 break;
2539 case SSH_SMSG_FAILURE:
2540 break;
2541 default:
2542 /* Unknown packet */
2543 packet_disconnect("Protocol error for port forward request:"
2544 "received packet type %d.", type);
2545 }
2546 }
2547 if (success) {
2548 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2549 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2550 permitted_opens[num_permitted_opens].listen_port = listen_port;
2551 num_permitted_opens++;
2552 }
2553 return (success ? 0 : -1);
2554 }
2555
2556 /*
2557 * Request cancellation of remote forwarding of connection host:port from
2558 * local side.
2559 */
2560 void
2561 channel_request_rforward_cancel(const char *host, u_short port)
2562 {
2563 int i;
2564
2565 if (!compat20)
2566 return;
2567
2568 for (i = 0; i < num_permitted_opens; i++) {
2569 if (permitted_opens[i].host_to_connect != NULL &&
2570 permitted_opens[i].listen_port == port)
2571 break;
2572 }
2573 if (i >= num_permitted_opens) {
2574 debug("%s: requested forward not found", __func__);
2575 return;
2576 }
2577 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2578 packet_put_cstring("cancel-tcpip-forward");
2579 packet_put_char(0);
2580 packet_put_cstring(host == NULL ? "" : host);
2581 packet_put_int(port);
2582 packet_send();
2583
2584 permitted_opens[i].listen_port = 0;
2585 permitted_opens[i].port_to_connect = 0;
2586 xfree(permitted_opens[i].host_to_connect);
2587 permitted_opens[i].host_to_connect = NULL;
2588 }
2589
2590 /*
2591 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
2592 * listening for the port, and sends back a success reply (or disconnect
2593 * message if there was an error).
2594 */
2595 int
2596 channel_input_port_forward_request(int is_root, int gateway_ports)
2597 {
2598 u_short port, host_port;
2599 int success = 0;
2600 char *hostname;
2601
2602 /* Get arguments from the packet. */
2603 port = packet_get_int();
2604 hostname = packet_get_string(NULL);
2605 host_port = packet_get_int();
2606
2607 #ifndef HAVE_CYGWIN
2608 /*
2609 * Check that an unprivileged user is not trying to forward a
2610 * privileged port.
2611 */
2612 if (port < IPPORT_RESERVED && !is_root)
2613 packet_disconnect(
2614 "Requested forwarding of port %d but user is not root.",
2615 port);
2616 if (host_port == 0)
2617 packet_disconnect("Dynamic forwarding denied.");
2618 #endif
2619
2620 /* Initiate forwarding */
2621 success = channel_setup_local_fwd_listener(NULL, port, hostname,
2622 host_port, gateway_ports);
2623
2624 /* Free the argument string. */
2625 xfree(hostname);
2626
2627 return (success ? 0 : -1);
2628 }
2629
2630 /*
2631 * Permits opening to any host/port if permitted_opens[] is empty. This is
2632 * usually called by the server, because the user could connect to any port
2633 * anyway, and the server has no way to know but to trust the client anyway.
2634 */
2635 void
2636 channel_permit_all_opens(void)
2637 {
2638 if (num_permitted_opens == 0)
2639 all_opens_permitted = 1;
2640 }
2641
2642 void
2643 channel_add_permitted_opens(char *host, int port)
2644 {
2645 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2646 fatal("channel_add_permitted_opens: too many forwards");
2647 debug("allow port forwarding to host %s port %d", host, port);
2648
2649 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
2650 permitted_opens[num_permitted_opens].port_to_connect = port;
2651 num_permitted_opens++;
2652
2653 all_opens_permitted = 0;
2654 }
2655
2656 void
2657 channel_add_adm_permitted_opens(char *host, int port)
2658 {
2659 if (num_adm_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2660 fatal("channel_add_adm_permitted_opens: too many forwards");
2661 debug("allow port forwarding to host %s port %d", host, port);
2662
2663 permitted_adm_opens[num_adm_permitted_opens].host_to_connect
2664 = xstrdup(host);
2665 permitted_adm_opens[num_adm_permitted_opens].port_to_connect = port;
2666 num_adm_permitted_opens++;
2667 }
2668
2669 void
2670 channel_clear_permitted_opens(void)
2671 {
2672 int i;
2673
2674 for (i = 0; i < num_permitted_opens; i++)
2675 if (permitted_opens[i].host_to_connect != NULL)
2676 xfree(permitted_opens[i].host_to_connect);
2677 num_permitted_opens = 0;
2678 }
2679
2680 void
2681 channel_clear_adm_permitted_opens(void)
2682 {
2683 int i;
2684
2685 for (i = 0; i < num_adm_permitted_opens; i++)
2686 if (permitted_adm_opens[i].host_to_connect != NULL)
2687 xfree(permitted_adm_opens[i].host_to_connect);
2688 num_adm_permitted_opens = 0;
2689 }
2690
2691 /* return socket to remote host, port */
2692 static int
2693 connect_to(const char *host, u_short port)
2694 {
2695 struct addrinfo hints, *ai, *aitop;
2696 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2697 int gaierr;
2698 int sock = -1;
2699
2700 memset(&hints, 0, sizeof(hints));
2701 hints.ai_family = IPv4or6;
2702 hints.ai_socktype = SOCK_STREAM;
2703 snprintf(strport, sizeof strport, "%d", port);
2704 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
2705 error("connect_to %.100s: unknown host (%s)", host,
2706 gai_strerror(gaierr));
2707 return -1;
2708 }
2709 for (ai = aitop; ai; ai = ai->ai_next) {
2710 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2711 continue;
2712 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2713 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2714 error("connect_to: getnameinfo failed");
2715 continue;
2716 }
2717 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2718 if (sock < 0) {
2719 if (ai->ai_next == NULL)
2720 error("socket: %.100s", strerror(errno));
2721 else
2722 verbose("socket: %.100s", strerror(errno));
2723 continue;
2724 }
2725 if (set_nonblock(sock) == -1)
2726 fatal("%s: set_nonblock(%d)", __func__, sock);
2727 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 &&
2728 errno != EINPROGRESS) {
2729 error("connect_to %.100s port %s: %.100s", ntop, strport,
2730 strerror(errno));
2731 close(sock);
2732 continue; /* fail -- try next */
2733 }
2734 break; /* success */
2735
2736 }
2737 freeaddrinfo(aitop);
2738 if (!ai) {
2739 error("connect_to %.100s port %d: failed.", host, port);
2740 return -1;
2741 }
2742 /* success */
2743 set_nodelay(sock);
2744 return sock;
2745 }
2746
2747 int
2748 channel_connect_by_listen_address(u_short listen_port)
2749 {
2750 int i;
2751
2752 for (i = 0; i < num_permitted_opens; i++)
2753 if (permitted_opens[i].host_to_connect != NULL &&
2754 permitted_opens[i].listen_port == listen_port)
2755 return connect_to(
2756 permitted_opens[i].host_to_connect,
2757 permitted_opens[i].port_to_connect);
2758 error("WARNING: Server requests forwarding for unknown listen_port %d",
2759 listen_port);
2760 return -1;
2761 }
2762
2763 /* Check if connecting to that port is permitted and connect. */
2764 int
2765 channel_connect_to(const char *host, u_short port)
2766 {
2767 int i, permit, permit_adm = 1;
2768
2769 permit = all_opens_permitted;
2770 if (!permit) {
2771 for (i = 0; i < num_permitted_opens; i++)
2772 if (permitted_opens[i].host_to_connect != NULL &&
2773 permitted_opens[i].port_to_connect == port &&
2774 strcmp(permitted_opens[i].host_to_connect, host) == 0)
2775 permit = 1;
2776 }
2777
2778 if (num_adm_permitted_opens > 0) {
2779 permit_adm = 0;
2780 for (i = 0; i < num_adm_permitted_opens; i++)
2781 if (permitted_adm_opens[i].host_to_connect != NULL &&
2782 permitted_adm_opens[i].port_to_connect == port &&
2783 strcmp(permitted_adm_opens[i].host_to_connect, host)
2784 == 0)
2785 permit_adm = 1;
2786 }
2787
2788 if (!permit || !permit_adm) {
2789 logit("Received request to connect to host %.100s port %d, "
2790 "but the request was denied.", host, port);
2791 return -1;
2792 }
2793 return connect_to(host, port);
2794 }
2795
2796 void
2797 channel_send_window_changes(void)
2798 {
2799 u_int i;
2800 struct winsize ws;
2801
2802 for (i = 0; i < channels_alloc; i++) {
2803 if (channels[i] == NULL || !channels[i]->client_tty ||
2804 channels[i]->type != SSH_CHANNEL_OPEN)
2805 continue;
2806 if (ioctl(channels[i]->rfd, TIOCGWINSZ, &ws) < 0)
2807 continue;
2808 channel_request_start(i, "window-change", 0);
2809 packet_put_int((u_int)ws.ws_col);
2810 packet_put_int((u_int)ws.ws_row);
2811 packet_put_int((u_int)ws.ws_xpixel);
2812 packet_put_int((u_int)ws.ws_ypixel);
2813 packet_send();
2814 }
2815 }
2816
2817 /* -- X11 forwarding */
2818
2819 /*
2820 * Creates an internet domain socket for listening for X11 connections.
2821 * Returns 0 and a suitable display number for the DISPLAY variable
2822 * stored in display_numberp , or -1 if an error occurs.
2823 */
2824 int
2825 x11_create_display_inet(int x11_display_offset, int x11_use_localhost,
2826 int single_connection, u_int *display_numberp, int **chanids)
2827 {
2828 Channel *nc = NULL;
2829 int display_number, sock;
2830 u_short port;
2831 struct addrinfo hints, *ai, *aitop;
2832 char strport[NI_MAXSERV];
2833 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
2834
2835 if (chanids == NULL)
2836 return -1;
2837
2838 for (display_number = x11_display_offset;
2839 display_number < MAX_DISPLAYS;
2840 display_number++) {
2841 port = 6000 + display_number;
2842 memset(&hints, 0, sizeof(hints));
2843 hints.ai_family = IPv4or6;
2844 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE;
2845 hints.ai_socktype = SOCK_STREAM;
2846 snprintf(strport, sizeof strport, "%d", port);
2847 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
2848 error("getaddrinfo: %.100s", gai_strerror(gaierr));
2849 return -1;
2850 }
2851 for (ai = aitop; ai; ai = ai->ai_next) {
2852 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2853 continue;
2854 sock = socket(ai->ai_family, ai->ai_socktype,
2855 ai->ai_protocol);
2856 if (sock < 0) {
2857 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
2858 error("socket: %.100s", strerror(errno));
2859 freeaddrinfo(aitop);
2860 return -1;
2861 } else {
2862 debug("x11_create_display_inet: Socket family %d not supported",
2863 ai->ai_family);
2864 continue;
2865 }
2866 }
2867 #ifdef IPV6_V6ONLY
2868 if (ai->ai_family == AF_INET6) {
2869 int on = 1;
2870 if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) < 0)
2871 error("setsockopt IPV6_V6ONLY: %.100s", strerror(errno));
2872 }
2873 #endif
2874 channel_set_reuseaddr(sock);
2875 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2876 debug2("bind port %d: %.100s", port, strerror(errno));
2877 close(sock);
2878
2879 if (ai->ai_next)
2880 continue;
2881
2882 for (n = 0; n < num_socks; n++) {
2883 close(socks[n]);
2884 }
2885 num_socks = 0;
2886 break;
2887 }
2888 socks[num_socks++] = sock;
2889 #ifndef DONT_TRY_OTHER_AF
2890 if (num_socks == NUM_SOCKS)
2891 break;
2892 #else
2893 if (x11_use_localhost) {
2894 if (num_socks == NUM_SOCKS)
2895 break;
2896 } else {
2897 break;
2898 }
2899 #endif
2900 }
2901 freeaddrinfo(aitop);
2902 if (num_socks > 0)
2903 break;
2904 }
2905 if (display_number >= MAX_DISPLAYS) {
2906 error("Failed to allocate internet-domain X11 display socket.");
2907 return -1;
2908 }
2909 /* Start listening for connections on the socket. */
2910 for (n = 0; n < num_socks; n++) {
2911 sock = socks[n];
2912 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2913 error("listen: %.100s", strerror(errno));
2914 close(sock);
2915 return -1;
2916 }
2917 }
2918
2919 /* Allocate a channel for each socket. */
2920 *chanids = xcalloc(num_socks + 1, sizeof(**chanids));
2921 for (n = 0; n < num_socks; n++) {
2922 sock = socks[n];
2923 nc = channel_new("x11 listener",
2924 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
2925 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2926 0, "X11 inet listener", 1);
2927 nc->single_connection = single_connection;
2928 (*chanids)[n] = nc->self;
2929 }
2930 (*chanids)[n] = -1;
2931
2932 /* Return the display number for the DISPLAY environment variable. */
2933 *display_numberp = display_number;
2934 return (0);
2935 }
2936
2937 static int
2938 connect_local_xsocket(u_int dnr)
2939 {
2940 int sock;
2941 struct sockaddr_un addr;
2942
2943 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2944 if (sock < 0)
2945 error("socket: %.100s", strerror(errno));
2946 memset(&addr, 0, sizeof(addr));
2947 addr.sun_family = AF_UNIX;
2948 snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr);
2949 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0)
2950 return sock;
2951 close(sock);
2952 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
2953 return -1;
2954 }
2955
2956 int
2957 x11_connect_display(void)
2958 {
2959 u_int display_number;
2960 const char *display;
2961 char buf[1024], *cp;
2962 struct addrinfo hints, *ai, *aitop;
2963 char strport[NI_MAXSERV];
2964 int gaierr, sock = 0;
2965
2966 /* Try to open a socket for the local X server. */
2967 display = getenv("DISPLAY");
2968 if (!display) {
2969 error("DISPLAY not set.");
2970 return -1;
2971 }
2972 /*
2973 * Now we decode the value of the DISPLAY variable and make a
2974 * connection to the real X server.
2975 */
2976
2977 /*
2978 * Check if it is a unix domain socket. Unix domain displays are in
2979 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
2980 */
2981 if (strncmp(display, "unix:", 5) == 0 ||
2982 display[0] == ':') {
2983 /* Connect to the unix domain socket. */
2984 if (sscanf(strrchr(display, ':') + 1, "%u", &display_number) != 1) {
2985 error("Could not parse display number from DISPLAY: %.100s",
2986 display);
2987 return -1;
2988 }
2989 /* Create a socket. */
2990 sock = connect_local_xsocket(display_number);
2991 if (sock < 0)
2992 return -1;
2993
2994 /* OK, we now have a connection to the display. */
2995 return sock;
2996 }
2997 /*
2998 * Connect to an inet socket. The DISPLAY value is supposedly
2999 * hostname:d[.s], where hostname may also be numeric IP address.
3000 */
3001 strlcpy(buf, display, sizeof(buf));
3002 cp = strchr(buf, ':');
3003 if (!cp) {
3004 error("Could not find ':' in DISPLAY: %.100s", display);
3005 return -1;
3006 }
3007 *cp = 0;
3008 /* buf now contains the host name. But first we parse the display number. */
3009 if (sscanf(cp + 1, "%u", &display_number) != 1) {
3010 error("Could not parse display number from DISPLAY: %.100s",
3011 display);
3012 return -1;
3013 }
3014
3015 /* Look up the host address */
3016 memset(&hints, 0, sizeof(hints));
3017 hints.ai_family = IPv4or6;
3018 hints.ai_socktype = SOCK_STREAM;
3019 snprintf(strport, sizeof strport, "%u", 6000 + display_number);
3020 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
3021 error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr));
3022 return -1;
3023 }
3024 for (ai = aitop; ai; ai = ai->ai_next) {
3025 /* Create a socket. */
3026 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
3027 if (sock < 0) {
3028 debug2("socket: %.100s", strerror(errno));
3029 continue;
3030 }
3031 /* Connect it to the display. */
3032 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
3033 debug2("connect %.100s port %u: %.100s", buf,
3034 6000 + display_number, strerror(errno));
3035 close(sock);
3036 continue;
3037 }
3038 /* Success */
3039 break;
3040 }
3041 freeaddrinfo(aitop);
3042 if (!ai) {
3043 error("connect %.100s port %u: %.100s", buf, 6000 + display_number,
3044 strerror(errno));
3045 return -1;
3046 }
3047 set_nodelay(sock);
3048 return sock;
3049 }
3050
3051 /*
3052 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
3053 * the remote channel number. We should do whatever we want, and respond
3054 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
3055 */
3056
3057 void
3058 x11_input_open(int type, u_int32_t seq, void *ctxt)
3059 {
3060 Channel *c = NULL;
3061 int remote_id, sock = 0;
3062 char *remote_host;
3063
3064 debug("Received X11 open request.");
3065
3066 remote_id = packet_get_int();
3067
3068 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
3069 remote_host = packet_get_string(NULL);
3070 } else {
3071 remote_host = xstrdup("unknown (remote did not supply name)");
3072 }
3073 packet_check_eom();
3074
3075 /* Obtain a connection to the real X display. */
3076 sock = x11_connect_display();
3077 if (sock != -1) {
3078 /* Allocate a channel for this connection. */
3079 c = channel_new("connected x11 socket",
3080 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
3081 remote_host, 1);
3082 c->remote_id = remote_id;
3083 c->force_drain = 1;
3084 }
3085 xfree(remote_host);
3086 if (c == NULL) {
3087 /* Send refusal to the remote host. */
3088 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3089 packet_put_int(remote_id);
3090 } else {
3091 /* Send a confirmation to the remote host. */
3092 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
3093 packet_put_int(remote_id);
3094 packet_put_int(c->self);
3095 }
3096 packet_send();
3097 }
3098
3099 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
3100 void
3101 deny_input_open(int type, u_int32_t seq, void *ctxt)
3102 {
3103 int rchan = packet_get_int();
3104
3105 switch (type) {
3106 case SSH_SMSG_AGENT_OPEN:
3107 error("Warning: ssh server tried agent forwarding.");
3108 break;
3109 case SSH_SMSG_X11_OPEN:
3110 error("Warning: ssh server tried X11 forwarding.");
3111 break;
3112 default:
3113 error("deny_input_open: type %d", type);
3114 break;
3115 }
3116 error("Warning: this is probably a break-in attempt by a malicious server.");
3117 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3118 packet_put_int(rchan);
3119 packet_send();
3120 }
3121
3122 /*
3123 * Requests forwarding of X11 connections, generates fake authentication
3124 * data, and enables authentication spoofing.
3125 * This should be called in the client only.
3126 */
3127 void
3128 x11_request_forwarding_with_spoofing(int client_session_id, const char *disp,
3129 const char *proto, const char *data)
3130 {
3131 u_int data_len = (u_int) strlen(data) / 2;
3132 u_int i, value;
3133 char *new_data;
3134 int screen_number;
3135 const char *cp;
3136 u_int32_t rnd = 0;
3137
3138 if (x11_saved_display == NULL)
3139 x11_saved_display = xstrdup(disp);
3140 else if (strcmp(disp, x11_saved_display) != 0) {
3141 error("x11_request_forwarding_with_spoofing: different "
3142 "$DISPLAY already forwarded");
3143 return;
3144 }
3145
3146 cp = disp;
3147 if (disp)
3148 cp = strchr(disp, ':');
3149 if (cp)
3150 cp = strchr(cp, '.');
3151 if (cp)
3152 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL);
3153 else
3154 screen_number = 0;
3155
3156 if (x11_saved_proto == NULL) {
3157 /* Save protocol name. */
3158 x11_saved_proto = xstrdup(proto);
3159 /*
3160 * Extract real authentication data and generate fake data
3161 * of the same length.
3162 */
3163 x11_saved_data = xmalloc(data_len);
3164 x11_fake_data = xmalloc(data_len);
3165 for (i = 0; i < data_len; i++) {
3166 if (sscanf(data + 2 * i, "%2x", &value) != 1)
3167 fatal("x11_request_forwarding: bad "
3168 "authentication data: %.100s", data);
3169 if (i % 4 == 0)
3170 rnd = arc4random();
3171 x11_saved_data[i] = value;
3172 x11_fake_data[i] = rnd & 0xff;
3173 rnd >>= 8;
3174 }
3175 x11_saved_data_len = data_len;
3176 x11_fake_data_len = data_len;
3177 }
3178
3179 /* Convert the fake data into hex. */
3180 new_data = tohex(x11_fake_data, data_len);
3181
3182 /* Send the request packet. */
3183 if (compat20) {
3184 channel_request_start(client_session_id, "x11-req", 0);
3185 packet_put_char(0); /* XXX bool single connection */
3186 } else {
3187 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
3188 }
3189 packet_put_cstring(proto);
3190 packet_put_cstring(new_data);
3191 packet_put_int(screen_number);
3192 packet_send();
3193 packet_write_wait();
3194 xfree(new_data);
3195 }
3196
3197
3198 /* -- agent forwarding */
3199
3200 /* Sends a message to the server to request authentication fd forwarding. */
3201
3202 void
3203 auth_request_forwarding(void)
3204 {
3205 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
3206 packet_send();
3207 packet_write_wait();
3208 }
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