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Import OpenSSH-6.7p1.
[dragonfly.git] / crypto / openssh / channels.c
blobd67fdf48b1fa00dd371f064e6492cb3d6cd1fb08
1 /* $OpenBSD: channels.c,v 1.336 2014/07/15 15:54:14 millert Exp $ */
2 /*
3 * Author: Tatu Ylonen <ylo@cs.hut.fi>
4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5 * All rights reserved
6 * This file contains functions for generic socket connection forwarding.
7 * There is also code for initiating connection forwarding for X11 connections,
8 * arbitrary tcp/ip connections, and the authentication agent connection.
9 *
10 * As far as I am concerned, the code I have written for this software
11 * can be used freely for any purpose. Any derived versions of this
12 * software must be clearly marked as such, and if the derived work is
13 * incompatible with the protocol description in the RFC file, it must be
14 * called by a name other than "ssh" or "Secure Shell".
15 *
16 * SSH2 support added by Markus Friedl.
17 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved.
18 * Copyright (c) 1999 Dug Song. All rights reserved.
19 * Copyright (c) 1999 Theo de Raadt. All rights reserved.
20 *
21 * Redistribution and use in source and binary forms, with or without
22 * modification, are permitted provided that the following conditions
23 * are met:
24 * 1. Redistributions of source code must retain the above copyright
25 * notice, this list of conditions and the following disclaimer.
26 * 2. Redistributions in binary form must reproduce the above copyright
27 * notice, this list of conditions and the following disclaimer in the
28 * documentation and/or other materials provided with the distribution.
29 *
30 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
31 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
32 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
33 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
34 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
35 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
36 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
37 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
38 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
39 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
40 */
41
42 #include "includes.h"
43
44 #include <sys/types.h>
45 #include <sys/stat.h>
46 #include <sys/ioctl.h>
47 #include <sys/un.h>
48 #include <sys/socket.h>
49 #ifdef HAVE_SYS_TIME_H
50 # include <sys/time.h>
51 #endif
52
53 #include <netinet/in.h>
54 #include <arpa/inet.h>
55
56 #include <errno.h>
57 #include <fcntl.h>
58 #include <netdb.h>
59 #include <stdio.h>
60 #include <stdlib.h>
61 #include <string.h>
62 #include <termios.h>
63 #include <unistd.h>
64 #include <stdarg.h>
65
66 #include "openbsd-compat/sys-queue.h"
67 #include "xmalloc.h"
68 #include "ssh.h"
69 #include "ssh1.h"
70 #include "ssh2.h"
71 #include "packet.h"
72 #include "log.h"
73 #include "misc.h"
74 #include "buffer.h"
75 #include "channels.h"
76 #include "compat.h"
77 #include "canohost.h"
78 #include "key.h"
79 #include "authfd.h"
80 #include "pathnames.h"
81
82 /* -- channel core */
83
84 /*
85 * Pointer to an array containing all allocated channels. The array is
86 * dynamically extended as needed.
87 */
88 static Channel **channels = NULL;
89
90 /*
91 * Size of the channel array. All slots of the array must always be
92 * initialized (at least the type field); unused slots set to NULL
93 */
94 static u_int channels_alloc = 0;
95
96 /*
97 * Maximum file descriptor value used in any of the channels. This is
98 * updated in channel_new.
99 */
100 static int channel_max_fd = 0;
101
102
103 /* -- tcp forwarding */
104
105 /*
106 * Data structure for storing which hosts are permitted for forward requests.
107 * The local sides of any remote forwards are stored in this array to prevent
108 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local
109 * network (which might be behind a firewall).
110 */
111 /* XXX: streamlocal wants a path instead of host:port */
112 /* Overload host_to_connect; we could just make this match Forward */
113 /* XXX - can we use listen_host instead of listen_path? */
114 typedef struct {
115 char *host_to_connect; /* Connect to 'host'. */
116 int port_to_connect; /* Connect to 'port'. */
117 char *listen_host; /* Remote side should listen address. */
118 char *listen_path; /* Remote side should listen path. */
119 int listen_port; /* Remote side should listen port. */
120 } ForwardPermission;
121
122 /* List of all permitted host/port pairs to connect by the user. */
123 static ForwardPermission *permitted_opens = NULL;
124
125 /* List of all permitted host/port pairs to connect by the admin. */
126 static ForwardPermission *permitted_adm_opens = NULL;
127
128 /* Number of permitted host/port pairs in the array permitted by the user. */
129 static int num_permitted_opens = 0;
130
131 /* Number of permitted host/port pair in the array permitted by the admin. */
132 static int num_adm_permitted_opens = 0;
133
134 /* special-case port number meaning allow any port */
135 #define FWD_PERMIT_ANY_PORT 0
136
137 /*
138 * If this is true, all opens are permitted. This is the case on the server
139 * on which we have to trust the client anyway, and the user could do
140 * anything after logging in anyway.
141 */
142 static int all_opens_permitted = 0;
143
144
145 /* -- X11 forwarding */
146
147 /* Maximum number of fake X11 displays to try. */
148 #define MAX_DISPLAYS 1000
149
150 /* Saved X11 local (client) display. */
151 static char *x11_saved_display = NULL;
152
153 /* Saved X11 authentication protocol name. */
154 static char *x11_saved_proto = NULL;
155
156 /* Saved X11 authentication data. This is the real data. */
157 static char *x11_saved_data = NULL;
158 static u_int x11_saved_data_len = 0;
159
160 /*
161 * Fake X11 authentication data. This is what the server will be sending us;
162 * we should replace any occurrences of this by the real data.
163 */
164 static u_char *x11_fake_data = NULL;
165 static u_int x11_fake_data_len;
166
167
168 /* -- agent forwarding */
169
170 #define NUM_SOCKS 10
171
172 /* AF_UNSPEC or AF_INET or AF_INET6 */
173 static int IPv4or6 = AF_UNSPEC;
174
175 /* helper */
176 static void port_open_helper(Channel *c, char *rtype);
177
178 /* non-blocking connect helpers */
179 static int connect_next(struct channel_connect *);
180 static void channel_connect_ctx_free(struct channel_connect *);
181
182 /* -- channel core */
183
184 Channel *
185 channel_by_id(int id)
186 {
187 Channel *c;
188
189 if (id < 0 || (u_int)id >= channels_alloc) {
190 logit("channel_by_id: %d: bad id", id);
191 return NULL;
192 }
193 c = channels[id];
194 if (c == NULL) {
195 logit("channel_by_id: %d: bad id: channel free", id);
196 return NULL;
197 }
198 return c;
199 }
200
201 /*
202 * Returns the channel if it is allowed to receive protocol messages.
203 * Private channels, like listening sockets, may not receive messages.
204 */
205 Channel *
206 channel_lookup(int id)
207 {
208 Channel *c;
209
210 if ((c = channel_by_id(id)) == NULL)
211 return (NULL);
212
213 switch (c->type) {
214 case SSH_CHANNEL_X11_OPEN:
215 case SSH_CHANNEL_LARVAL:
216 case SSH_CHANNEL_CONNECTING:
217 case SSH_CHANNEL_DYNAMIC:
218 case SSH_CHANNEL_OPENING:
219 case SSH_CHANNEL_OPEN:
220 case SSH_CHANNEL_INPUT_DRAINING:
221 case SSH_CHANNEL_OUTPUT_DRAINING:
222 case SSH_CHANNEL_ABANDONED:
223 return (c);
224 }
225 logit("Non-public channel %d, type %d.", id, c->type);
226 return (NULL);
227 }
228
229 /*
230 * Register filedescriptors for a channel, used when allocating a channel or
231 * when the channel consumer/producer is ready, e.g. shell exec'd
232 */
233 static void
234 channel_register_fds(Channel *c, int rfd, int wfd, int efd,
235 int extusage, int nonblock, int is_tty)
236 {
237 /* Update the maximum file descriptor value. */
238 channel_max_fd = MAX(channel_max_fd, rfd);
239 channel_max_fd = MAX(channel_max_fd, wfd);
240 channel_max_fd = MAX(channel_max_fd, efd);
241
242 if (rfd != -1)
243 fcntl(rfd, F_SETFD, FD_CLOEXEC);
244 if (wfd != -1 && wfd != rfd)
245 fcntl(wfd, F_SETFD, FD_CLOEXEC);
246 if (efd != -1 && efd != rfd && efd != wfd)
247 fcntl(efd, F_SETFD, FD_CLOEXEC);
248
249 c->rfd = rfd;
250 c->wfd = wfd;
251 c->sock = (rfd == wfd) ? rfd : -1;
252 c->efd = efd;
253 c->extended_usage = extusage;
254
255 if ((c->isatty = is_tty) != 0)
256 debug2("channel %d: rfd %d isatty", c->self, c->rfd);
257 #ifdef _AIX
258 /* XXX: Later AIX versions can't push as much data to tty */
259 c->wfd_isatty = is_tty || isatty(c->wfd);
260 #endif
261
262 /* enable nonblocking mode */
263 if (nonblock) {
264 if (rfd != -1)
265 set_nonblock(rfd);
266 if (wfd != -1)
267 set_nonblock(wfd);
268 if (efd != -1)
269 set_nonblock(efd);
270 }
271 }
272
273 /*
274 * Allocate a new channel object and set its type and socket. This will cause
275 * remote_name to be freed.
276 */
277 Channel *
278 channel_new(char *ctype, int type, int rfd, int wfd, int efd,
279 u_int window, u_int maxpack, int extusage, char *remote_name, int nonblock)
280 {
281 int found;
282 u_int i;
283 Channel *c;
284
285 /* Do initial allocation if this is the first call. */
286 if (channels_alloc == 0) {
287 channels_alloc = 10;
288 channels = xcalloc(channels_alloc, sizeof(Channel *));
289 for (i = 0; i < channels_alloc; i++)
290 channels[i] = NULL;
291 }
292 /* Try to find a free slot where to put the new channel. */
293 for (found = -1, i = 0; i < channels_alloc; i++)
294 if (channels[i] == NULL) {
295 /* Found a free slot. */
296 found = (int)i;
297 break;
298 }
299 if (found < 0) {
300 /* There are no free slots. Take last+1 slot and expand the array. */
301 found = channels_alloc;
302 if (channels_alloc > 10000)
303 fatal("channel_new: internal error: channels_alloc %d "
304 "too big.", channels_alloc);
305 channels = xrealloc(channels, channels_alloc + 10,
306 sizeof(Channel *));
307 channels_alloc += 10;
308 debug2("channel: expanding %d", channels_alloc);
309 for (i = found; i < channels_alloc; i++)
310 channels[i] = NULL;
311 }
312 /* Initialize and return new channel. */
313 c = channels[found] = xcalloc(1, sizeof(Channel));
314 buffer_init(&c->input);
315 buffer_init(&c->output);
316 buffer_init(&c->extended);
317 c->path = NULL;
318 c->listening_addr = NULL;
319 c->listening_port = 0;
320 c->ostate = CHAN_OUTPUT_OPEN;
321 c->istate = CHAN_INPUT_OPEN;
322 c->flags = 0;
323 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock, 0);
324 c->notbefore = 0;
325 c->self = found;
326 c->type = type;
327 c->ctype = ctype;
328 c->local_window = window;
329 c->local_window_max = window;
330 c->local_consumed = 0;
331 c->local_maxpacket = maxpack;
332 c->remote_id = -1;
333 c->remote_name = xstrdup(remote_name);
334 c->remote_window = 0;
335 c->remote_maxpacket = 0;
336 c->force_drain = 0;
337 c->single_connection = 0;
338 c->detach_user = NULL;
339 c->detach_close = 0;
340 c->open_confirm = NULL;
341 c->open_confirm_ctx = NULL;
342 c->input_filter = NULL;
343 c->output_filter = NULL;
344 c->filter_ctx = NULL;
345 c->filter_cleanup = NULL;
346 c->ctl_chan = -1;
347 c->mux_rcb = NULL;
348 c->mux_ctx = NULL;
349 c->mux_pause = 0;
350 c->delayed = 1; /* prevent call to channel_post handler */
351 TAILQ_INIT(&c->status_confirms);
352 debug("channel %d: new [%s]", found, remote_name);
353 return c;
354 }
355
356 static int
357 channel_find_maxfd(void)
358 {
359 u_int i;
360 int max = 0;
361 Channel *c;
362
363 for (i = 0; i < channels_alloc; i++) {
364 c = channels[i];
365 if (c != NULL) {
366 max = MAX(max, c->rfd);
367 max = MAX(max, c->wfd);
368 max = MAX(max, c->efd);
369 }
370 }
371 return max;
372 }
373
374 int
375 channel_close_fd(int *fdp)
376 {
377 int ret = 0, fd = *fdp;
378
379 if (fd != -1) {
380 ret = close(fd);
381 *fdp = -1;
382 if (fd == channel_max_fd)
383 channel_max_fd = channel_find_maxfd();
384 }
385 return ret;
386 }
387
388 /* Close all channel fd/socket. */
389 static void
390 channel_close_fds(Channel *c)
391 {
392 channel_close_fd(&c->sock);
393 channel_close_fd(&c->rfd);
394 channel_close_fd(&c->wfd);
395 channel_close_fd(&c->efd);
396 }
397
398 /* Free the channel and close its fd/socket. */
399 void
400 channel_free(Channel *c)
401 {
402 char *s;
403 u_int i, n;
404 struct channel_confirm *cc;
405
406 for (n = 0, i = 0; i < channels_alloc; i++)
407 if (channels[i])
408 n++;
409 debug("channel %d: free: %s, nchannels %u", c->self,
410 c->remote_name ? c->remote_name : "???", n);
411
412 s = channel_open_message();
413 debug3("channel %d: status: %s", c->self, s);
414 free(s);
415
416 if (c->sock != -1)
417 shutdown(c->sock, SHUT_RDWR);
418 channel_close_fds(c);
419 buffer_free(&c->input);
420 buffer_free(&c->output);
421 buffer_free(&c->extended);
422 free(c->remote_name);
423 c->remote_name = NULL;
424 free(c->path);
425 c->path = NULL;
426 free(c->listening_addr);
427 c->listening_addr = NULL;
428 while ((cc = TAILQ_FIRST(&c->status_confirms)) != NULL) {
429 if (cc->abandon_cb != NULL)
430 cc->abandon_cb(c, cc->ctx);
431 TAILQ_REMOVE(&c->status_confirms, cc, entry);
432 explicit_bzero(cc, sizeof(*cc));
433 free(cc);
434 }
435 if (c->filter_cleanup != NULL && c->filter_ctx != NULL)
436 c->filter_cleanup(c->self, c->filter_ctx);
437 channels[c->self] = NULL;
438 free(c);
439 }
440
441 void
442 channel_free_all(void)
443 {
444 u_int i;
445
446 for (i = 0; i < channels_alloc; i++)
447 if (channels[i] != NULL)
448 channel_free(channels[i]);
449 }
450
451 /*
452 * Closes the sockets/fds of all channels. This is used to close extra file
453 * descriptors after a fork.
454 */
455 void
456 channel_close_all(void)
457 {
458 u_int i;
459
460 for (i = 0; i < channels_alloc; i++)
461 if (channels[i] != NULL)
462 channel_close_fds(channels[i]);
463 }
464
465 /*
466 * Stop listening to channels.
467 */
468 void
469 channel_stop_listening(void)
470 {
471 u_int i;
472 Channel *c;
473
474 for (i = 0; i < channels_alloc; i++) {
475 c = channels[i];
476 if (c != NULL) {
477 switch (c->type) {
478 case SSH_CHANNEL_AUTH_SOCKET:
479 case SSH_CHANNEL_PORT_LISTENER:
480 case SSH_CHANNEL_RPORT_LISTENER:
481 case SSH_CHANNEL_X11_LISTENER:
482 case SSH_CHANNEL_UNIX_LISTENER:
483 case SSH_CHANNEL_RUNIX_LISTENER:
484 channel_close_fd(&c->sock);
485 channel_free(c);
486 break;
487 }
488 }
489 }
490 }
491
492 /*
493 * Returns true if no channel has too much buffered data, and false if one or
494 * more channel is overfull.
495 */
496 int
497 channel_not_very_much_buffered_data(void)
498 {
499 u_int i;
500 Channel *c;
501
502 for (i = 0; i < channels_alloc; i++) {
503 c = channels[i];
504 if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
505 #if 0
506 if (!compat20 &&
507 buffer_len(&c->input) > packet_get_maxsize()) {
508 debug2("channel %d: big input buffer %d",
509 c->self, buffer_len(&c->input));
510 return 0;
511 }
512 #endif
513 if (buffer_len(&c->output) > packet_get_maxsize()) {
514 debug2("channel %d: big output buffer %u > %u",
515 c->self, buffer_len(&c->output),
516 packet_get_maxsize());
517 return 0;
518 }
519 }
520 }
521 return 1;
522 }
523
524 /* Returns true if any channel is still open. */
525 int
526 channel_still_open(void)
527 {
528 u_int i;
529 Channel *c;
530
531 for (i = 0; i < channels_alloc; i++) {
532 c = channels[i];
533 if (c == NULL)
534 continue;
535 switch (c->type) {
536 case SSH_CHANNEL_X11_LISTENER:
537 case SSH_CHANNEL_PORT_LISTENER:
538 case SSH_CHANNEL_RPORT_LISTENER:
539 case SSH_CHANNEL_MUX_LISTENER:
540 case SSH_CHANNEL_CLOSED:
541 case SSH_CHANNEL_AUTH_SOCKET:
542 case SSH_CHANNEL_DYNAMIC:
543 case SSH_CHANNEL_CONNECTING:
544 case SSH_CHANNEL_ZOMBIE:
545 case SSH_CHANNEL_ABANDONED:
546 case SSH_CHANNEL_UNIX_LISTENER:
547 case SSH_CHANNEL_RUNIX_LISTENER:
548 continue;
549 case SSH_CHANNEL_LARVAL:
550 if (!compat20)
551 fatal("cannot happen: SSH_CHANNEL_LARVAL");
552 continue;
553 case SSH_CHANNEL_OPENING:
554 case SSH_CHANNEL_OPEN:
555 case SSH_CHANNEL_X11_OPEN:
556 case SSH_CHANNEL_MUX_CLIENT:
557 return 1;
558 case SSH_CHANNEL_INPUT_DRAINING:
559 case SSH_CHANNEL_OUTPUT_DRAINING:
560 if (!compat13)
561 fatal("cannot happen: OUT_DRAIN");
562 return 1;
563 default:
564 fatal("channel_still_open: bad channel type %d", c->type);
565 /* NOTREACHED */
566 }
567 }
568 return 0;
569 }
570
571 /* Returns the id of an open channel suitable for keepaliving */
572 int
573 channel_find_open(void)
574 {
575 u_int i;
576 Channel *c;
577
578 for (i = 0; i < channels_alloc; i++) {
579 c = channels[i];
580 if (c == NULL || c->remote_id < 0)
581 continue;
582 switch (c->type) {
583 case SSH_CHANNEL_CLOSED:
584 case SSH_CHANNEL_DYNAMIC:
585 case SSH_CHANNEL_X11_LISTENER:
586 case SSH_CHANNEL_PORT_LISTENER:
587 case SSH_CHANNEL_RPORT_LISTENER:
588 case SSH_CHANNEL_MUX_LISTENER:
589 case SSH_CHANNEL_MUX_CLIENT:
590 case SSH_CHANNEL_OPENING:
591 case SSH_CHANNEL_CONNECTING:
592 case SSH_CHANNEL_ZOMBIE:
593 case SSH_CHANNEL_ABANDONED:
594 case SSH_CHANNEL_UNIX_LISTENER:
595 case SSH_CHANNEL_RUNIX_LISTENER:
596 continue;
597 case SSH_CHANNEL_LARVAL:
598 case SSH_CHANNEL_AUTH_SOCKET:
599 case SSH_CHANNEL_OPEN:
600 case SSH_CHANNEL_X11_OPEN:
601 return i;
602 case SSH_CHANNEL_INPUT_DRAINING:
603 case SSH_CHANNEL_OUTPUT_DRAINING:
604 if (!compat13)
605 fatal("cannot happen: OUT_DRAIN");
606 return i;
607 default:
608 fatal("channel_find_open: bad channel type %d", c->type);
609 /* NOTREACHED */
610 }
611 }
612 return -1;
613 }
614
615
616 /*
617 * Returns a message describing the currently open forwarded connections,
618 * suitable for sending to the client. The message contains crlf pairs for
619 * newlines.
620 */
621 char *
622 channel_open_message(void)
623 {
624 Buffer buffer;
625 Channel *c;
626 char buf[1024], *cp;
627 u_int i;
628
629 buffer_init(&buffer);
630 snprintf(buf, sizeof buf, "The following connections are open:\r\n");
631 buffer_append(&buffer, buf, strlen(buf));
632 for (i = 0; i < channels_alloc; i++) {
633 c = channels[i];
634 if (c == NULL)
635 continue;
636 switch (c->type) {
637 case SSH_CHANNEL_X11_LISTENER:
638 case SSH_CHANNEL_PORT_LISTENER:
639 case SSH_CHANNEL_RPORT_LISTENER:
640 case SSH_CHANNEL_CLOSED:
641 case SSH_CHANNEL_AUTH_SOCKET:
642 case SSH_CHANNEL_ZOMBIE:
643 case SSH_CHANNEL_ABANDONED:
644 case SSH_CHANNEL_MUX_CLIENT:
645 case SSH_CHANNEL_MUX_LISTENER:
646 case SSH_CHANNEL_UNIX_LISTENER:
647 case SSH_CHANNEL_RUNIX_LISTENER:
648 continue;
649 case SSH_CHANNEL_LARVAL:
650 case SSH_CHANNEL_OPENING:
651 case SSH_CHANNEL_CONNECTING:
652 case SSH_CHANNEL_DYNAMIC:
653 case SSH_CHANNEL_OPEN:
654 case SSH_CHANNEL_X11_OPEN:
655 case SSH_CHANNEL_INPUT_DRAINING:
656 case SSH_CHANNEL_OUTPUT_DRAINING:
657 snprintf(buf, sizeof buf,
658 " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d cc %d)\r\n",
659 c->self, c->remote_name,
660 c->type, c->remote_id,
661 c->istate, buffer_len(&c->input),
662 c->ostate, buffer_len(&c->output),
663 c->rfd, c->wfd, c->ctl_chan);
664 buffer_append(&buffer, buf, strlen(buf));
665 continue;
666 default:
667 fatal("channel_open_message: bad channel type %d", c->type);
668 /* NOTREACHED */
669 }
670 }
671 buffer_append(&buffer, "\0", 1);
672 cp = xstrdup(buffer_ptr(&buffer));
673 buffer_free(&buffer);
674 return cp;
675 }
676
677 void
678 channel_send_open(int id)
679 {
680 Channel *c = channel_lookup(id);
681
682 if (c == NULL) {
683 logit("channel_send_open: %d: bad id", id);
684 return;
685 }
686 debug2("channel %d: send open", id);
687 packet_start(SSH2_MSG_CHANNEL_OPEN);
688 packet_put_cstring(c->ctype);
689 packet_put_int(c->self);
690 packet_put_int(c->local_window);
691 packet_put_int(c->local_maxpacket);
692 packet_send();
693 }
694
695 void
696 channel_request_start(int id, char *service, int wantconfirm)
697 {
698 Channel *c = channel_lookup(id);
699
700 if (c == NULL) {
701 logit("channel_request_start: %d: unknown channel id", id);
702 return;
703 }
704 debug2("channel %d: request %s confirm %d", id, service, wantconfirm);
705 packet_start(SSH2_MSG_CHANNEL_REQUEST);
706 packet_put_int(c->remote_id);
707 packet_put_cstring(service);
708 packet_put_char(wantconfirm);
709 }
710
711 void
712 channel_register_status_confirm(int id, channel_confirm_cb *cb,
713 channel_confirm_abandon_cb *abandon_cb, void *ctx)
714 {
715 struct channel_confirm *cc;
716 Channel *c;
717
718 if ((c = channel_lookup(id)) == NULL)
719 fatal("channel_register_expect: %d: bad id", id);
720
721 cc = xcalloc(1, sizeof(*cc));
722 cc->cb = cb;
723 cc->abandon_cb = abandon_cb;
724 cc->ctx = ctx;
725 TAILQ_INSERT_TAIL(&c->status_confirms, cc, entry);
726 }
727
728 void
729 channel_register_open_confirm(int id, channel_open_fn *fn, void *ctx)
730 {
731 Channel *c = channel_lookup(id);
732
733 if (c == NULL) {
734 logit("channel_register_open_confirm: %d: bad id", id);
735 return;
736 }
737 c->open_confirm = fn;
738 c->open_confirm_ctx = ctx;
739 }
740
741 void
742 channel_register_cleanup(int id, channel_callback_fn *fn, int do_close)
743 {
744 Channel *c = channel_by_id(id);
745
746 if (c == NULL) {
747 logit("channel_register_cleanup: %d: bad id", id);
748 return;
749 }
750 c->detach_user = fn;
751 c->detach_close = do_close;
752 }
753
754 void
755 channel_cancel_cleanup(int id)
756 {
757 Channel *c = channel_by_id(id);
758
759 if (c == NULL) {
760 logit("channel_cancel_cleanup: %d: bad id", id);
761 return;
762 }
763 c->detach_user = NULL;
764 c->detach_close = 0;
765 }
766
767 void
768 channel_register_filter(int id, channel_infilter_fn *ifn,
769 channel_outfilter_fn *ofn, channel_filter_cleanup_fn *cfn, void *ctx)
770 {
771 Channel *c = channel_lookup(id);
772
773 if (c == NULL) {
774 logit("channel_register_filter: %d: bad id", id);
775 return;
776 }
777 c->input_filter = ifn;
778 c->output_filter = ofn;
779 c->filter_ctx = ctx;
780 c->filter_cleanup = cfn;
781 }
782
783 void
784 channel_set_fds(int id, int rfd, int wfd, int efd,
785 int extusage, int nonblock, int is_tty, u_int window_max)
786 {
787 Channel *c = channel_lookup(id);
788
789 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
790 fatal("channel_activate for non-larval channel %d.", id);
791 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock, is_tty);
792 c->type = SSH_CHANNEL_OPEN;
793 c->local_window = c->local_window_max = window_max;
794 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
795 packet_put_int(c->remote_id);
796 packet_put_int(c->local_window);
797 packet_send();
798 }
799
800 /*
801 * 'channel_pre*' are called just before select() to add any bits relevant to
802 * channels in the select bitmasks.
803 */
804 /*
805 * 'channel_post*': perform any appropriate operations for channels which
806 * have events pending.
807 */
808 typedef void chan_fn(Channel *c, fd_set *readset, fd_set *writeset);
809 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
810 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
811
812 /* ARGSUSED */
813 static void
814 channel_pre_listener(Channel *c, fd_set *readset, fd_set *writeset)
815 {
816 FD_SET(c->sock, readset);
817 }
818
819 /* ARGSUSED */
820 static void
821 channel_pre_connecting(Channel *c, fd_set *readset, fd_set *writeset)
822 {
823 debug3("channel %d: waiting for connection", c->self);
824 FD_SET(c->sock, writeset);
825 }
826
827 static void
828 channel_pre_open_13(Channel *c, fd_set *readset, fd_set *writeset)
829 {
830 if (buffer_len(&c->input) < packet_get_maxsize())
831 FD_SET(c->sock, readset);
832 if (buffer_len(&c->output) > 0)
833 FD_SET(c->sock, writeset);
834 }
835
836 static void
837 channel_pre_open(Channel *c, fd_set *readset, fd_set *writeset)
838 {
839 u_int limit = compat20 ? c->remote_window : packet_get_maxsize();
840
841 if (c->istate == CHAN_INPUT_OPEN &&
842 limit > 0 &&
843 buffer_len(&c->input) < limit &&
844 buffer_check_alloc(&c->input, CHAN_RBUF))
845 FD_SET(c->rfd, readset);
846 if (c->ostate == CHAN_OUTPUT_OPEN ||
847 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
848 if (buffer_len(&c->output) > 0) {
849 FD_SET(c->wfd, writeset);
850 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
851 if (CHANNEL_EFD_OUTPUT_ACTIVE(c))
852 debug2("channel %d: obuf_empty delayed efd %d/(%d)",
853 c->self, c->efd, buffer_len(&c->extended));
854 else
855 chan_obuf_empty(c);
856 }
857 }
858 /** XXX check close conditions, too */
859 if (compat20 && c->efd != -1 &&
860 !(c->istate == CHAN_INPUT_CLOSED && c->ostate == CHAN_OUTPUT_CLOSED)) {
861 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
862 buffer_len(&c->extended) > 0)
863 FD_SET(c->efd, writeset);
864 else if (c->efd != -1 && !(c->flags & CHAN_EOF_SENT) &&
865 (c->extended_usage == CHAN_EXTENDED_READ ||
866 c->extended_usage == CHAN_EXTENDED_IGNORE) &&
867 buffer_len(&c->extended) < c->remote_window)
868 FD_SET(c->efd, readset);
869 }
870 /* XXX: What about efd? races? */
871 }
872
873 /* ARGSUSED */
874 static void
875 channel_pre_input_draining(Channel *c, fd_set *readset, fd_set *writeset)
876 {
877 if (buffer_len(&c->input) == 0) {
878 packet_start(SSH_MSG_CHANNEL_CLOSE);
879 packet_put_int(c->remote_id);
880 packet_send();
881 c->type = SSH_CHANNEL_CLOSED;
882 debug2("channel %d: closing after input drain.", c->self);
883 }
884 }
885
886 /* ARGSUSED */
887 static void
888 channel_pre_output_draining(Channel *c, fd_set *readset, fd_set *writeset)
889 {
890 if (buffer_len(&c->output) == 0)
891 chan_mark_dead(c);
892 else
893 FD_SET(c->sock, writeset);
894 }
895
896 /*
897 * This is a special state for X11 authentication spoofing. An opened X11
898 * connection (when authentication spoofing is being done) remains in this
899 * state until the first packet has been completely read. The authentication
900 * data in that packet is then substituted by the real data if it matches the
901 * fake data, and the channel is put into normal mode.
902 * XXX All this happens at the client side.
903 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
904 */
905 static int
906 x11_open_helper(Buffer *b)
907 {
908 u_char *ucp;
909 u_int proto_len, data_len;
910
911 /* Check if the fixed size part of the packet is in buffer. */
912 if (buffer_len(b) < 12)
913 return 0;
914
915 /* Parse the lengths of variable-length fields. */
916 ucp = buffer_ptr(b);
917 if (ucp[0] == 0x42) { /* Byte order MSB first. */
918 proto_len = 256 * ucp[6] + ucp[7];
919 data_len = 256 * ucp[8] + ucp[9];
920 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
921 proto_len = ucp[6] + 256 * ucp[7];
922 data_len = ucp[8] + 256 * ucp[9];
923 } else {
924 debug2("Initial X11 packet contains bad byte order byte: 0x%x",
925 ucp[0]);
926 return -1;
927 }
928
929 /* Check if the whole packet is in buffer. */
930 if (buffer_len(b) <
931 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
932 return 0;
933
934 /* Check if authentication protocol matches. */
935 if (proto_len != strlen(x11_saved_proto) ||
936 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
937 debug2("X11 connection uses different authentication protocol.");
938 return -1;
939 }
940 /* Check if authentication data matches our fake data. */
941 if (data_len != x11_fake_data_len ||
942 timingsafe_bcmp(ucp + 12 + ((proto_len + 3) & ~3),
943 x11_fake_data, x11_fake_data_len) != 0) {
944 debug2("X11 auth data does not match fake data.");
945 return -1;
946 }
947 /* Check fake data length */
948 if (x11_fake_data_len != x11_saved_data_len) {
949 error("X11 fake_data_len %d != saved_data_len %d",
950 x11_fake_data_len, x11_saved_data_len);
951 return -1;
952 }
953 /*
954 * Received authentication protocol and data match
955 * our fake data. Substitute the fake data with real
956 * data.
957 */
958 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
959 x11_saved_data, x11_saved_data_len);
960 return 1;
961 }
962
963 static void
964 channel_pre_x11_open_13(Channel *c, fd_set *readset, fd_set *writeset)
965 {
966 int ret = x11_open_helper(&c->output);
967
968 if (ret == 1) {
969 /* Start normal processing for the channel. */
970 c->type = SSH_CHANNEL_OPEN;
971 channel_pre_open_13(c, readset, writeset);
972 } else if (ret == -1) {
973 /*
974 * We have received an X11 connection that has bad
975 * authentication information.
976 */
977 logit("X11 connection rejected because of wrong authentication.");
978 buffer_clear(&c->input);
979 buffer_clear(&c->output);
980 channel_close_fd(&c->sock);
981 c->sock = -1;
982 c->type = SSH_CHANNEL_CLOSED;
983 packet_start(SSH_MSG_CHANNEL_CLOSE);
984 packet_put_int(c->remote_id);
985 packet_send();
986 }
987 }
988
989 static void
990 channel_pre_x11_open(Channel *c, fd_set *readset, fd_set *writeset)
991 {
992 int ret = x11_open_helper(&c->output);
993
994 /* c->force_drain = 1; */
995
996 if (ret == 1) {
997 c->type = SSH_CHANNEL_OPEN;
998 channel_pre_open(c, readset, writeset);
999 } else if (ret == -1) {
1000 logit("X11 connection rejected because of wrong authentication.");
1001 debug2("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
1002 chan_read_failed(c);
1003 buffer_clear(&c->input);
1004 chan_ibuf_empty(c);
1005 buffer_clear(&c->output);
1006 /* for proto v1, the peer will send an IEOF */
1007 if (compat20)
1008 chan_write_failed(c);
1009 else
1010 c->type = SSH_CHANNEL_OPEN;
1011 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
1012 }
1013 }
1014
1015 static void
1016 channel_pre_mux_client(Channel *c, fd_set *readset, fd_set *writeset)
1017 {
1018 if (c->istate == CHAN_INPUT_OPEN && !c->mux_pause &&
1019 buffer_check_alloc(&c->input, CHAN_RBUF))
1020 FD_SET(c->rfd, readset);
1021 if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1022 /* clear buffer immediately (discard any partial packet) */
1023 buffer_clear(&c->input);
1024 chan_ibuf_empty(c);
1025 /* Start output drain. XXX just kill chan? */
1026 chan_rcvd_oclose(c);
1027 }
1028 if (c->ostate == CHAN_OUTPUT_OPEN ||
1029 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
1030 if (buffer_len(&c->output) > 0)
1031 FD_SET(c->wfd, writeset);
1032 else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN)
1033 chan_obuf_empty(c);
1034 }
1035 }
1036
1037 /* try to decode a socks4 header */
1038 /* ARGSUSED */
1039 static int
1040 channel_decode_socks4(Channel *c, fd_set *readset, fd_set *writeset)
1041 {
1042 char *p, *host;
1043 u_int len, have, i, found, need;
1044 char username[256];
1045 struct {
1046 u_int8_t version;
1047 u_int8_t command;
1048 u_int16_t dest_port;
1049 struct in_addr dest_addr;
1050 } s4_req, s4_rsp;
1051
1052 debug2("channel %d: decode socks4", c->self);
1053
1054 have = buffer_len(&c->input);
1055 len = sizeof(s4_req);
1056 if (have < len)
1057 return 0;
1058 p = buffer_ptr(&c->input);
1059
1060 need = 1;
1061 /* SOCKS4A uses an invalid IP address 0.0.0.x */
1062 if (p[4] == 0 && p[5] == 0 && p[6] == 0 && p[7] != 0) {
1063 debug2("channel %d: socks4a request", c->self);
1064 /* ... and needs an extra string (the hostname) */
1065 need = 2;
1066 }
1067 /* Check for terminating NUL on the string(s) */
1068 for (found = 0, i = len; i < have; i++) {
1069 if (p[i] == '\0') {
1070 found++;
1071 if (found == need)
1072 break;
1073 }
1074 if (i > 1024) {
1075 /* the peer is probably sending garbage */
1076 debug("channel %d: decode socks4: too long",
1077 c->self);
1078 return -1;
1079 }
1080 }
1081 if (found < need)
1082 return 0;
1083 buffer_get(&c->input, (char *)&s4_req.version, 1);
1084 buffer_get(&c->input, (char *)&s4_req.command, 1);
1085 buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
1086 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
1087 have = buffer_len(&c->input);
1088 p = buffer_ptr(&c->input);
1089 if (memchr(p, '\0', have) == NULL)
1090 fatal("channel %d: decode socks4: user not nul terminated",
1091 c->self);
1092 len = strlen(p);
1093 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
1094 len++; /* trailing '\0' */
1095 if (len > have)
1096 fatal("channel %d: decode socks4: len %d > have %d",
1097 c->self, len, have);
1098 strlcpy(username, p, sizeof(username));
1099 buffer_consume(&c->input, len);
1100
1101 free(c->path);
1102 c->path = NULL;
1103 if (need == 1) { /* SOCKS4: one string */
1104 host = inet_ntoa(s4_req.dest_addr);
1105 c->path = xstrdup(host);
1106 } else { /* SOCKS4A: two strings */
1107 have = buffer_len(&c->input);
1108 p = buffer_ptr(&c->input);
1109 len = strlen(p);
1110 debug2("channel %d: decode socks4a: host %s/%d",
1111 c->self, p, len);
1112 len++; /* trailing '\0' */
1113 if (len > have)
1114 fatal("channel %d: decode socks4a: len %d > have %d",
1115 c->self, len, have);
1116 if (len > NI_MAXHOST) {
1117 error("channel %d: hostname \"%.100s\" too long",
1118 c->self, p);
1119 return -1;
1120 }
1121 c->path = xstrdup(p);
1122 buffer_consume(&c->input, len);
1123 }
1124 c->host_port = ntohs(s4_req.dest_port);
1125
1126 debug2("channel %d: dynamic request: socks4 host %s port %u command %u",
1127 c->self, c->path, c->host_port, s4_req.command);
1128
1129 if (s4_req.command != 1) {
1130 debug("channel %d: cannot handle: %s cn %d",
1131 c->self, need == 1 ? "SOCKS4" : "SOCKS4A", s4_req.command);
1132 return -1;
1133 }
1134 s4_rsp.version = 0; /* vn: 0 for reply */
1135 s4_rsp.command = 90; /* cd: req granted */
1136 s4_rsp.dest_port = 0; /* ignored */
1137 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
1138 buffer_append(&c->output, &s4_rsp, sizeof(s4_rsp));
1139 return 1;
1140 }
1141
1142 /* try to decode a socks5 header */
1143 #define SSH_SOCKS5_AUTHDONE 0x1000
1144 #define SSH_SOCKS5_NOAUTH 0x00
1145 #define SSH_SOCKS5_IPV4 0x01
1146 #define SSH_SOCKS5_DOMAIN 0x03
1147 #define SSH_SOCKS5_IPV6 0x04
1148 #define SSH_SOCKS5_CONNECT 0x01
1149 #define SSH_SOCKS5_SUCCESS 0x00
1150
1151 /* ARGSUSED */
1152 static int
1153 channel_decode_socks5(Channel *c, fd_set *readset, fd_set *writeset)
1154 {
1155 struct {
1156 u_int8_t version;
1157 u_int8_t command;
1158 u_int8_t reserved;
1159 u_int8_t atyp;
1160 } s5_req, s5_rsp;
1161 u_int16_t dest_port;
1162 char dest_addr[255+1], ntop[INET6_ADDRSTRLEN];
1163 u_char *p;
1164 u_int have, need, i, found, nmethods, addrlen, af;
1165
1166 debug2("channel %d: decode socks5", c->self);
1167 p = buffer_ptr(&c->input);
1168 if (p[0] != 0x05)
1169 return -1;
1170 have = buffer_len(&c->input);
1171 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) {
1172 /* format: ver | nmethods | methods */
1173 if (have < 2)
1174 return 0;
1175 nmethods = p[1];
1176 if (have < nmethods + 2)
1177 return 0;
1178 /* look for method: "NO AUTHENTICATION REQUIRED" */
1179 for (found = 0, i = 2; i < nmethods + 2; i++) {
1180 if (p[i] == SSH_SOCKS5_NOAUTH) {
1181 found = 1;
1182 break;
1183 }
1184 }
1185 if (!found) {
1186 debug("channel %d: method SSH_SOCKS5_NOAUTH not found",
1187 c->self);
1188 return -1;
1189 }
1190 buffer_consume(&c->input, nmethods + 2);
1191 buffer_put_char(&c->output, 0x05); /* version */
1192 buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH); /* method */
1193 FD_SET(c->sock, writeset);
1194 c->flags |= SSH_SOCKS5_AUTHDONE;
1195 debug2("channel %d: socks5 auth done", c->self);
1196 return 0; /* need more */
1197 }
1198 debug2("channel %d: socks5 post auth", c->self);
1199 if (have < sizeof(s5_req)+1)
1200 return 0; /* need more */
1201 memcpy(&s5_req, p, sizeof(s5_req));
1202 if (s5_req.version != 0x05 ||
1203 s5_req.command != SSH_SOCKS5_CONNECT ||
1204 s5_req.reserved != 0x00) {
1205 debug2("channel %d: only socks5 connect supported", c->self);
1206 return -1;
1207 }
1208 switch (s5_req.atyp){
1209 case SSH_SOCKS5_IPV4:
1210 addrlen = 4;
1211 af = AF_INET;
1212 break;
1213 case SSH_SOCKS5_DOMAIN:
1214 addrlen = p[sizeof(s5_req)];
1215 af = -1;
1216 break;
1217 case SSH_SOCKS5_IPV6:
1218 addrlen = 16;
1219 af = AF_INET6;
1220 break;
1221 default:
1222 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp);
1223 return -1;
1224 }
1225 need = sizeof(s5_req) + addrlen + 2;
1226 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1227 need++;
1228 if (have < need)
1229 return 0;
1230 buffer_consume(&c->input, sizeof(s5_req));
1231 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1232 buffer_consume(&c->input, 1); /* host string length */
1233 buffer_get(&c->input, &dest_addr, addrlen);
1234 buffer_get(&c->input, (char *)&dest_port, 2);
1235 dest_addr[addrlen] = '\0';
1236 free(c->path);
1237 c->path = NULL;
1238 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) {
1239 if (addrlen >= NI_MAXHOST) {
1240 error("channel %d: dynamic request: socks5 hostname "
1241 "\"%.100s\" too long", c->self, dest_addr);
1242 return -1;
1243 }
1244 c->path = xstrdup(dest_addr);
1245 } else {
1246 if (inet_ntop(af, dest_addr, ntop, sizeof(ntop)) == NULL)
1247 return -1;
1248 c->path = xstrdup(ntop);
1249 }
1250 c->host_port = ntohs(dest_port);
1251
1252 debug2("channel %d: dynamic request: socks5 host %s port %u command %u",
1253 c->self, c->path, c->host_port, s5_req.command);
1254
1255 s5_rsp.version = 0x05;
1256 s5_rsp.command = SSH_SOCKS5_SUCCESS;
1257 s5_rsp.reserved = 0; /* ignored */
1258 s5_rsp.atyp = SSH_SOCKS5_IPV4;
1259 dest_port = 0; /* ignored */
1260
1261 buffer_append(&c->output, &s5_rsp, sizeof(s5_rsp));
1262 buffer_put_int(&c->output, ntohl(INADDR_ANY)); /* bind address */
1263 buffer_append(&c->output, &dest_port, sizeof(dest_port));
1264 return 1;
1265 }
1266
1267 Channel *
1268 channel_connect_stdio_fwd(const char *host_to_connect, u_short port_to_connect,
1269 int in, int out)
1270 {
1271 Channel *c;
1272
1273 debug("channel_connect_stdio_fwd %s:%d", host_to_connect,
1274 port_to_connect);
1275
1276 c = channel_new("stdio-forward", SSH_CHANNEL_OPENING, in, out,
1277 -1, CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
1278 0, "stdio-forward", /*nonblock*/0);
1279
1280 c->path = xstrdup(host_to_connect);
1281 c->host_port = port_to_connect;
1282 c->listening_port = 0;
1283 c->force_drain = 1;
1284
1285 channel_register_fds(c, in, out, -1, 0, 1, 0);
1286 port_open_helper(c, "direct-tcpip");
1287
1288 return c;
1289 }
1290
1291 /* dynamic port forwarding */
1292 static void
1293 channel_pre_dynamic(Channel *c, fd_set *readset, fd_set *writeset)
1294 {
1295 u_char *p;
1296 u_int have;
1297 int ret;
1298
1299 have = buffer_len(&c->input);
1300 debug2("channel %d: pre_dynamic: have %d", c->self, have);
1301 /* buffer_dump(&c->input); */
1302 /* check if the fixed size part of the packet is in buffer. */
1303 if (have < 3) {
1304 /* need more */
1305 FD_SET(c->sock, readset);
1306 return;
1307 }
1308 /* try to guess the protocol */
1309 p = buffer_ptr(&c->input);
1310 switch (p[0]) {
1311 case 0x04:
1312 ret = channel_decode_socks4(c, readset, writeset);
1313 break;
1314 case 0x05:
1315 ret = channel_decode_socks5(c, readset, writeset);
1316 break;
1317 default:
1318 ret = -1;
1319 break;
1320 }
1321 if (ret < 0) {
1322 chan_mark_dead(c);
1323 } else if (ret == 0) {
1324 debug2("channel %d: pre_dynamic: need more", c->self);
1325 /* need more */
1326 FD_SET(c->sock, readset);
1327 } else {
1328 /* switch to the next state */
1329 c->type = SSH_CHANNEL_OPENING;
1330 port_open_helper(c, "direct-tcpip");
1331 }
1332 }
1333
1334 /* This is our fake X11 server socket. */
1335 /* ARGSUSED */
1336 static void
1337 channel_post_x11_listener(Channel *c, fd_set *readset, fd_set *writeset)
1338 {
1339 Channel *nc;
1340 struct sockaddr_storage addr;
1341 int newsock, oerrno;
1342 socklen_t addrlen;
1343 char buf[16384], *remote_ipaddr;
1344 int remote_port;
1345
1346 if (FD_ISSET(c->sock, readset)) {
1347 debug("X11 connection requested.");
1348 addrlen = sizeof(addr);
1349 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1350 if (c->single_connection) {
1351 oerrno = errno;
1352 debug2("single_connection: closing X11 listener.");
1353 channel_close_fd(&c->sock);
1354 chan_mark_dead(c);
1355 errno = oerrno;
1356 }
1357 if (newsock < 0) {
1358 if (errno != EINTR && errno != EWOULDBLOCK &&
1359 errno != ECONNABORTED)
1360 error("accept: %.100s", strerror(errno));
1361 if (errno == EMFILE || errno == ENFILE)
1362 c->notbefore = monotime() + 1;
1363 return;
1364 }
1365 set_nodelay(newsock);
1366 remote_ipaddr = get_peer_ipaddr(newsock);
1367 remote_port = get_peer_port(newsock);
1368 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1369 remote_ipaddr, remote_port);
1370
1371 nc = channel_new("accepted x11 socket",
1372 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1373 c->local_window_max, c->local_maxpacket, 0, buf, 1);
1374 if (compat20) {
1375 packet_start(SSH2_MSG_CHANNEL_OPEN);
1376 packet_put_cstring("x11");
1377 packet_put_int(nc->self);
1378 packet_put_int(nc->local_window_max);
1379 packet_put_int(nc->local_maxpacket);
1380 /* originator ipaddr and port */
1381 packet_put_cstring(remote_ipaddr);
1382 if (datafellows & SSH_BUG_X11FWD) {
1383 debug2("ssh2 x11 bug compat mode");
1384 } else {
1385 packet_put_int(remote_port);
1386 }
1387 packet_send();
1388 } else {
1389 packet_start(SSH_SMSG_X11_OPEN);
1390 packet_put_int(nc->self);
1391 if (packet_get_protocol_flags() &
1392 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1393 packet_put_cstring(buf);
1394 packet_send();
1395 }
1396 free(remote_ipaddr);
1397 }
1398 }
1399
1400 static void
1401 port_open_helper(Channel *c, char *rtype)
1402 {
1403 char buf[1024];
1404 char *local_ipaddr = get_local_ipaddr(c->sock);
1405 int local_port = c->sock == -1 ? 65536 : get_sock_port(c->sock, 1);
1406 char *remote_ipaddr = get_peer_ipaddr(c->sock);
1407 int remote_port = get_peer_port(c->sock);
1408
1409 if (remote_port == -1) {
1410 /* Fake addr/port to appease peers that validate it (Tectia) */
1411 free(remote_ipaddr);
1412 remote_ipaddr = xstrdup("127.0.0.1");
1413 remote_port = 65535;
1414 }
1415
1416 snprintf(buf, sizeof buf,
1417 "%s: listening port %d for %.100s port %d, "
1418 "connect from %.200s port %d to %.100s port %d",
1419 rtype, c->listening_port, c->path, c->host_port,
1420 remote_ipaddr, remote_port, local_ipaddr, local_port);
1421
1422 free(c->remote_name);
1423 c->remote_name = xstrdup(buf);
1424
1425 if (compat20) {
1426 packet_start(SSH2_MSG_CHANNEL_OPEN);
1427 packet_put_cstring(rtype);
1428 packet_put_int(c->self);
1429 packet_put_int(c->local_window_max);
1430 packet_put_int(c->local_maxpacket);
1431 if (strcmp(rtype, "direct-tcpip") == 0) {
1432 /* target host, port */
1433 packet_put_cstring(c->path);
1434 packet_put_int(c->host_port);
1435 } else if (strcmp(rtype, "direct-streamlocal@openssh.com") == 0) {
1436 /* target path */
1437 packet_put_cstring(c->path);
1438 } else if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) {
1439 /* listen path */
1440 packet_put_cstring(c->path);
1441 } else {
1442 /* listen address, port */
1443 packet_put_cstring(c->path);
1444 packet_put_int(local_port);
1445 }
1446 if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) {
1447 /* reserved for future owner/mode info */
1448 packet_put_cstring("");
1449 } else {
1450 /* originator host and port */
1451 packet_put_cstring(remote_ipaddr);
1452 packet_put_int((u_int)remote_port);
1453 }
1454 packet_send();
1455 } else {
1456 packet_start(SSH_MSG_PORT_OPEN);
1457 packet_put_int(c->self);
1458 packet_put_cstring(c->path);
1459 packet_put_int(c->host_port);
1460 if (packet_get_protocol_flags() &
1461 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1462 packet_put_cstring(c->remote_name);
1463 packet_send();
1464 }
1465 free(remote_ipaddr);
1466 free(local_ipaddr);
1467 }
1468
1469 static void
1470 channel_set_reuseaddr(int fd)
1471 {
1472 int on = 1;
1473
1474 /*
1475 * Set socket options.
1476 * Allow local port reuse in TIME_WAIT.
1477 */
1478 if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1)
1479 error("setsockopt SO_REUSEADDR fd %d: %s", fd, strerror(errno));
1480 }
1481
1482 /*
1483 * This socket is listening for connections to a forwarded TCP/IP port.
1484 */
1485 /* ARGSUSED */
1486 static void
1487 channel_post_port_listener(Channel *c, fd_set *readset, fd_set *writeset)
1488 {
1489 Channel *nc;
1490 struct sockaddr_storage addr;
1491 int newsock, nextstate;
1492 socklen_t addrlen;
1493 char *rtype;
1494
1495 if (FD_ISSET(c->sock, readset)) {
1496 debug("Connection to port %d forwarding "
1497 "to %.100s port %d requested.",
1498 c->listening_port, c->path, c->host_port);
1499
1500 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1501 nextstate = SSH_CHANNEL_OPENING;
1502 rtype = "forwarded-tcpip";
1503 } else if (c->type == SSH_CHANNEL_RUNIX_LISTENER) {
1504 nextstate = SSH_CHANNEL_OPENING;
1505 rtype = "forwarded-streamlocal@openssh.com";
1506 } else if (c->host_port == PORT_STREAMLOCAL) {
1507 nextstate = SSH_CHANNEL_OPENING;
1508 rtype = "direct-streamlocal@openssh.com";
1509 } else if (c->host_port == 0) {
1510 nextstate = SSH_CHANNEL_DYNAMIC;
1511 rtype = "dynamic-tcpip";
1512 } else {
1513 nextstate = SSH_CHANNEL_OPENING;
1514 rtype = "direct-tcpip";
1515 }
1516
1517 addrlen = sizeof(addr);
1518 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1519 if (newsock < 0) {
1520 if (errno != EINTR && errno != EWOULDBLOCK &&
1521 errno != ECONNABORTED)
1522 error("accept: %.100s", strerror(errno));
1523 if (errno == EMFILE || errno == ENFILE)
1524 c->notbefore = monotime() + 1;
1525 return;
1526 }
1527 if (c->host_port != PORT_STREAMLOCAL)
1528 set_nodelay(newsock);
1529 nc = channel_new(rtype, nextstate, newsock, newsock, -1,
1530 c->local_window_max, c->local_maxpacket, 0, rtype, 1);
1531 nc->listening_port = c->listening_port;
1532 nc->host_port = c->host_port;
1533 if (c->path != NULL)
1534 nc->path = xstrdup(c->path);
1535
1536 if (nextstate != SSH_CHANNEL_DYNAMIC)
1537 port_open_helper(nc, rtype);
1538 }
1539 }
1540
1541 /*
1542 * This is the authentication agent socket listening for connections from
1543 * clients.
1544 */
1545 /* ARGSUSED */
1546 static void
1547 channel_post_auth_listener(Channel *c, fd_set *readset, fd_set *writeset)
1548 {
1549 Channel *nc;
1550 int newsock;
1551 struct sockaddr_storage addr;
1552 socklen_t addrlen;
1553
1554 if (FD_ISSET(c->sock, readset)) {
1555 addrlen = sizeof(addr);
1556 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1557 if (newsock < 0) {
1558 error("accept from auth socket: %.100s",
1559 strerror(errno));
1560 if (errno == EMFILE || errno == ENFILE)
1561 c->notbefore = monotime() + 1;
1562 return;
1563 }
1564 nc = channel_new("accepted auth socket",
1565 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1566 c->local_window_max, c->local_maxpacket,
1567 0, "accepted auth socket", 1);
1568 if (compat20) {
1569 packet_start(SSH2_MSG_CHANNEL_OPEN);
1570 packet_put_cstring("auth-agent@openssh.com");
1571 packet_put_int(nc->self);
1572 packet_put_int(c->local_window_max);
1573 packet_put_int(c->local_maxpacket);
1574 } else {
1575 packet_start(SSH_SMSG_AGENT_OPEN);
1576 packet_put_int(nc->self);
1577 }
1578 packet_send();
1579 }
1580 }
1581
1582 /* ARGSUSED */
1583 static void
1584 channel_post_connecting(Channel *c, fd_set *readset, fd_set *writeset)
1585 {
1586 int err = 0, sock;
1587 socklen_t sz = sizeof(err);
1588
1589 if (FD_ISSET(c->sock, writeset)) {
1590 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) {
1591 err = errno;
1592 error("getsockopt SO_ERROR failed");
1593 }
1594 if (err == 0) {
1595 debug("channel %d: connected to %s port %d",
1596 c->self, c->connect_ctx.host, c->connect_ctx.port);
1597 channel_connect_ctx_free(&c->connect_ctx);
1598 c->type = SSH_CHANNEL_OPEN;
1599 if (compat20) {
1600 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1601 packet_put_int(c->remote_id);
1602 packet_put_int(c->self);
1603 packet_put_int(c->local_window);
1604 packet_put_int(c->local_maxpacket);
1605 } else {
1606 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1607 packet_put_int(c->remote_id);
1608 packet_put_int(c->self);
1609 }
1610 } else {
1611 debug("channel %d: connection failed: %s",
1612 c->self, strerror(err));
1613 /* Try next address, if any */
1614 if ((sock = connect_next(&c->connect_ctx)) > 0) {
1615 close(c->sock);
1616 c->sock = c->rfd = c->wfd = sock;
1617 channel_max_fd = channel_find_maxfd();
1618 return;
1619 }
1620 /* Exhausted all addresses */
1621 error("connect_to %.100s port %d: failed.",
1622 c->connect_ctx.host, c->connect_ctx.port);
1623 channel_connect_ctx_free(&c->connect_ctx);
1624 if (compat20) {
1625 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1626 packet_put_int(c->remote_id);
1627 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1628 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1629 packet_put_cstring(strerror(err));
1630 packet_put_cstring("");
1631 }
1632 } else {
1633 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1634 packet_put_int(c->remote_id);
1635 }
1636 chan_mark_dead(c);
1637 }
1638 packet_send();
1639 }
1640 }
1641
1642 /* ARGSUSED */
1643 static int
1644 channel_handle_rfd(Channel *c, fd_set *readset, fd_set *writeset)
1645 {
1646 char buf[CHAN_RBUF];
1647 int len, force;
1648
1649 force = c->isatty && c->detach_close && c->istate != CHAN_INPUT_CLOSED;
1650 if (c->rfd != -1 && (force || FD_ISSET(c->rfd, readset))) {
1651 errno = 0;
1652 len = read(c->rfd, buf, sizeof(buf));
1653 if (len < 0 && (errno == EINTR ||
1654 ((errno == EAGAIN || errno == EWOULDBLOCK) && !force)))
1655 return 1;
1656 #ifndef PTY_ZEROREAD
1657 if (len <= 0) {
1658 #else
1659 if ((!c->isatty && len <= 0) ||
1660 (c->isatty && (len < 0 || (len == 0 && errno != 0)))) {
1661 #endif
1662 debug2("channel %d: read<=0 rfd %d len %d",
1663 c->self, c->rfd, len);
1664 if (c->type != SSH_CHANNEL_OPEN) {
1665 debug2("channel %d: not open", c->self);
1666 chan_mark_dead(c);
1667 return -1;
1668 } else if (compat13) {
1669 buffer_clear(&c->output);
1670 c->type = SSH_CHANNEL_INPUT_DRAINING;
1671 debug2("channel %d: input draining.", c->self);
1672 } else {
1673 chan_read_failed(c);
1674 }
1675 return -1;
1676 }
1677 if (c->input_filter != NULL) {
1678 if (c->input_filter(c, buf, len) == -1) {
1679 debug2("channel %d: filter stops", c->self);
1680 chan_read_failed(c);
1681 }
1682 } else if (c->datagram) {
1683 buffer_put_string(&c->input, buf, len);
1684 } else {
1685 buffer_append(&c->input, buf, len);
1686 }
1687 }
1688 return 1;
1689 }
1690
1691 /* ARGSUSED */
1692 static int
1693 channel_handle_wfd(Channel *c, fd_set *readset, fd_set *writeset)
1694 {
1695 struct termios tio;
1696 u_char *data = NULL, *buf;
1697 u_int dlen, olen = 0;
1698 int len;
1699
1700 /* Send buffered output data to the socket. */
1701 if (c->wfd != -1 &&
1702 FD_ISSET(c->wfd, writeset) &&
1703 buffer_len(&c->output) > 0) {
1704 olen = buffer_len(&c->output);
1705 if (c->output_filter != NULL) {
1706 if ((buf = c->output_filter(c, &data, &dlen)) == NULL) {
1707 debug2("channel %d: filter stops", c->self);
1708 if (c->type != SSH_CHANNEL_OPEN)
1709 chan_mark_dead(c);
1710 else
1711 chan_write_failed(c);
1712 return -1;
1713 }
1714 } else if (c->datagram) {
1715 buf = data = buffer_get_string(&c->output, &dlen);
1716 } else {
1717 buf = data = buffer_ptr(&c->output);
1718 dlen = buffer_len(&c->output);
1719 }
1720
1721 if (c->datagram) {
1722 /* ignore truncated writes, datagrams might get lost */
1723 len = write(c->wfd, buf, dlen);
1724 free(data);
1725 if (len < 0 && (errno == EINTR || errno == EAGAIN ||
1726 errno == EWOULDBLOCK))
1727 return 1;
1728 if (len <= 0) {
1729 if (c->type != SSH_CHANNEL_OPEN)
1730 chan_mark_dead(c);
1731 else
1732 chan_write_failed(c);
1733 return -1;
1734 }
1735 goto out;
1736 }
1737 #ifdef _AIX
1738 /* XXX: Later AIX versions can't push as much data to tty */
1739 if (compat20 && c->wfd_isatty)
1740 dlen = MIN(dlen, 8*1024);
1741 #endif
1742
1743 len = write(c->wfd, buf, dlen);
1744 if (len < 0 &&
1745 (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK))
1746 return 1;
1747 if (len <= 0) {
1748 if (c->type != SSH_CHANNEL_OPEN) {
1749 debug2("channel %d: not open", c->self);
1750 chan_mark_dead(c);
1751 return -1;
1752 } else if (compat13) {
1753 buffer_clear(&c->output);
1754 debug2("channel %d: input draining.", c->self);
1755 c->type = SSH_CHANNEL_INPUT_DRAINING;
1756 } else {
1757 chan_write_failed(c);
1758 }
1759 return -1;
1760 }
1761 #ifndef BROKEN_TCGETATTR_ICANON
1762 if (compat20 && c->isatty && dlen >= 1 && buf[0] != '\r') {
1763 if (tcgetattr(c->wfd, &tio) == 0 &&
1764 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1765 /*
1766 * Simulate echo to reduce the impact of
1767 * traffic analysis. We need to match the
1768 * size of a SSH2_MSG_CHANNEL_DATA message
1769 * (4 byte channel id + buf)
1770 */
1771 packet_send_ignore(4 + len);
1772 packet_send();
1773 }
1774 }
1775 #endif
1776 buffer_consume(&c->output, len);
1777 }
1778 out:
1779 if (compat20 && olen > 0)
1780 c->local_consumed += olen - buffer_len(&c->output);
1781 return 1;
1782 }
1783
1784 static int
1785 channel_handle_efd(Channel *c, fd_set *readset, fd_set *writeset)
1786 {
1787 char buf[CHAN_RBUF];
1788 int len;
1789
1790 /** XXX handle drain efd, too */
1791 if (c->efd != -1) {
1792 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1793 FD_ISSET(c->efd, writeset) &&
1794 buffer_len(&c->extended) > 0) {
1795 len = write(c->efd, buffer_ptr(&c->extended),
1796 buffer_len(&c->extended));
1797 debug2("channel %d: written %d to efd %d",
1798 c->self, len, c->efd);
1799 if (len < 0 && (errno == EINTR || errno == EAGAIN ||
1800 errno == EWOULDBLOCK))
1801 return 1;
1802 if (len <= 0) {
1803 debug2("channel %d: closing write-efd %d",
1804 c->self, c->efd);
1805 channel_close_fd(&c->efd);
1806 } else {
1807 buffer_consume(&c->extended, len);
1808 c->local_consumed += len;
1809 }
1810 } else if (c->efd != -1 &&
1811 (c->extended_usage == CHAN_EXTENDED_READ ||
1812 c->extended_usage == CHAN_EXTENDED_IGNORE) &&
1813 (c->detach_close || FD_ISSET(c->efd, readset))) {
1814 len = read(c->efd, buf, sizeof(buf));
1815 debug2("channel %d: read %d from efd %d",
1816 c->self, len, c->efd);
1817 if (len < 0 && (errno == EINTR || ((errno == EAGAIN ||
1818 errno == EWOULDBLOCK) && !c->detach_close)))
1819 return 1;
1820 if (len <= 0) {
1821 debug2("channel %d: closing read-efd %d",
1822 c->self, c->efd);
1823 channel_close_fd(&c->efd);
1824 } else {
1825 if (c->extended_usage == CHAN_EXTENDED_IGNORE) {
1826 debug3("channel %d: discard efd",
1827 c->self);
1828 } else
1829 buffer_append(&c->extended, buf, len);
1830 }
1831 }
1832 }
1833 return 1;
1834 }
1835
1836 static int
1837 channel_check_window(Channel *c)
1838 {
1839 if (c->type == SSH_CHANNEL_OPEN &&
1840 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1841 ((c->local_window_max - c->local_window >
1842 c->local_maxpacket*3) ||
1843 c->local_window < c->local_window_max/2) &&
1844 c->local_consumed > 0) {
1845 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1846 packet_put_int(c->remote_id);
1847 packet_put_int(c->local_consumed);
1848 packet_send();
1849 debug2("channel %d: window %d sent adjust %d",
1850 c->self, c->local_window,
1851 c->local_consumed);
1852 c->local_window += c->local_consumed;
1853 c->local_consumed = 0;
1854 }
1855 return 1;
1856 }
1857
1858 static void
1859 channel_post_open(Channel *c, fd_set *readset, fd_set *writeset)
1860 {
1861 channel_handle_rfd(c, readset, writeset);
1862 channel_handle_wfd(c, readset, writeset);
1863 if (!compat20)
1864 return;
1865 channel_handle_efd(c, readset, writeset);
1866 channel_check_window(c);
1867 }
1868
1869 static u_int
1870 read_mux(Channel *c, u_int need)
1871 {
1872 char buf[CHAN_RBUF];
1873 int len;
1874 u_int rlen;
1875
1876 if (buffer_len(&c->input) < need) {
1877 rlen = need - buffer_len(&c->input);
1878 len = read(c->rfd, buf, MIN(rlen, CHAN_RBUF));
1879 if (len <= 0) {
1880 if (errno != EINTR && errno != EAGAIN) {
1881 debug2("channel %d: ctl read<=0 rfd %d len %d",
1882 c->self, c->rfd, len);
1883 chan_read_failed(c);
1884 return 0;
1885 }
1886 } else
1887 buffer_append(&c->input, buf, len);
1888 }
1889 return buffer_len(&c->input);
1890 }
1891
1892 static void
1893 channel_post_mux_client(Channel *c, fd_set *readset, fd_set *writeset)
1894 {
1895 u_int need;
1896 ssize_t len;
1897
1898 if (!compat20)
1899 fatal("%s: entered with !compat20", __func__);
1900
1901 if (c->rfd != -1 && !c->mux_pause && FD_ISSET(c->rfd, readset) &&
1902 (c->istate == CHAN_INPUT_OPEN ||
1903 c->istate == CHAN_INPUT_WAIT_DRAIN)) {
1904 /*
1905 * Don't not read past the precise end of packets to
1906 * avoid disrupting fd passing.
1907 */
1908 if (read_mux(c, 4) < 4) /* read header */
1909 return;
1910 need = get_u32(buffer_ptr(&c->input));
1911 #define CHANNEL_MUX_MAX_PACKET (256 * 1024)
1912 if (need > CHANNEL_MUX_MAX_PACKET) {
1913 debug2("channel %d: packet too big %u > %u",
1914 c->self, CHANNEL_MUX_MAX_PACKET, need);
1915 chan_rcvd_oclose(c);
1916 return;
1917 }
1918 if (read_mux(c, need + 4) < need + 4) /* read body */
1919 return;
1920 if (c->mux_rcb(c) != 0) {
1921 debug("channel %d: mux_rcb failed", c->self);
1922 chan_mark_dead(c);
1923 return;
1924 }
1925 }
1926
1927 if (c->wfd != -1 && FD_ISSET(c->wfd, writeset) &&
1928 buffer_len(&c->output) > 0) {
1929 len = write(c->wfd, buffer_ptr(&c->output),
1930 buffer_len(&c->output));
1931 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1932 return;
1933 if (len <= 0) {
1934 chan_mark_dead(c);
1935 return;
1936 }
1937 buffer_consume(&c->output, len);
1938 }
1939 }
1940
1941 static void
1942 channel_post_mux_listener(Channel *c, fd_set *readset, fd_set *writeset)
1943 {
1944 Channel *nc;
1945 struct sockaddr_storage addr;
1946 socklen_t addrlen;
1947 int newsock;
1948 uid_t euid;
1949 gid_t egid;
1950
1951 if (!FD_ISSET(c->sock, readset))
1952 return;
1953
1954 debug("multiplexing control connection");
1955
1956 /*
1957 * Accept connection on control socket
1958 */
1959 memset(&addr, 0, sizeof(addr));
1960 addrlen = sizeof(addr);
1961 if ((newsock = accept(c->sock, (struct sockaddr*)&addr,
1962 &addrlen)) == -1) {
1963 error("%s accept: %s", __func__, strerror(errno));
1964 if (errno == EMFILE || errno == ENFILE)
1965 c->notbefore = monotime() + 1;
1966 return;
1967 }
1968
1969 if (getpeereid(newsock, &euid, &egid) < 0) {
1970 error("%s getpeereid failed: %s", __func__,
1971 strerror(errno));
1972 close(newsock);
1973 return;
1974 }
1975 if ((euid != 0) && (getuid() != euid)) {
1976 error("multiplex uid mismatch: peer euid %u != uid %u",
1977 (u_int)euid, (u_int)getuid());
1978 close(newsock);
1979 return;
1980 }
1981 nc = channel_new("multiplex client", SSH_CHANNEL_MUX_CLIENT,
1982 newsock, newsock, -1, c->local_window_max,
1983 c->local_maxpacket, 0, "mux-control", 1);
1984 nc->mux_rcb = c->mux_rcb;
1985 debug3("%s: new mux channel %d fd %d", __func__,
1986 nc->self, nc->sock);
1987 /* establish state */
1988 nc->mux_rcb(nc);
1989 /* mux state transitions must not elicit protocol messages */
1990 nc->flags |= CHAN_LOCAL;
1991 }
1992
1993 /* ARGSUSED */
1994 static void
1995 channel_post_output_drain_13(Channel *c, fd_set *readset, fd_set *writeset)
1996 {
1997 int len;
1998
1999 /* Send buffered output data to the socket. */
2000 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
2001 len = write(c->sock, buffer_ptr(&c->output),
2002 buffer_len(&c->output));
2003 if (len <= 0)
2004 buffer_clear(&c->output);
2005 else
2006 buffer_consume(&c->output, len);
2007 }
2008 }
2009
2010 static void
2011 channel_handler_init_20(void)
2012 {
2013 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
2014 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
2015 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
2016 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
2017 channel_pre[SSH_CHANNEL_UNIX_LISTENER] = &channel_pre_listener;
2018 channel_pre[SSH_CHANNEL_RUNIX_LISTENER] = &channel_pre_listener;
2019 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
2020 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
2021 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
2022 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
2023 channel_pre[SSH_CHANNEL_MUX_LISTENER] = &channel_pre_listener;
2024 channel_pre[SSH_CHANNEL_MUX_CLIENT] = &channel_pre_mux_client;
2025
2026 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
2027 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
2028 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
2029 channel_post[SSH_CHANNEL_UNIX_LISTENER] = &channel_post_port_listener;
2030 channel_post[SSH_CHANNEL_RUNIX_LISTENER] = &channel_post_port_listener;
2031 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
2032 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
2033 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
2034 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
2035 channel_post[SSH_CHANNEL_MUX_LISTENER] = &channel_post_mux_listener;
2036 channel_post[SSH_CHANNEL_MUX_CLIENT] = &channel_post_mux_client;
2037 }
2038
2039 static void
2040 channel_handler_init_13(void)
2041 {
2042 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
2043 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
2044 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
2045 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
2046 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
2047 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
2048 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
2049 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
2050 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
2051
2052 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
2053 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
2054 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
2055 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
2056 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
2057 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
2058 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
2059 }
2060
2061 static void
2062 channel_handler_init_15(void)
2063 {
2064 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
2065 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
2066 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
2067 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
2068 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
2069 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
2070 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
2071
2072 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
2073 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
2074 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
2075 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
2076 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
2077 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
2078 }
2079
2080 static void
2081 channel_handler_init(void)
2082 {
2083 int i;
2084
2085 for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
2086 channel_pre[i] = NULL;
2087 channel_post[i] = NULL;
2088 }
2089 if (compat20)
2090 channel_handler_init_20();
2091 else if (compat13)
2092 channel_handler_init_13();
2093 else
2094 channel_handler_init_15();
2095 }
2096
2097 /* gc dead channels */
2098 static void
2099 channel_garbage_collect(Channel *c)
2100 {
2101 if (c == NULL)
2102 return;
2103 if (c->detach_user != NULL) {
2104 if (!chan_is_dead(c, c->detach_close))
2105 return;
2106 debug2("channel %d: gc: notify user", c->self);
2107 c->detach_user(c->self, NULL);
2108 /* if we still have a callback */
2109 if (c->detach_user != NULL)
2110 return;
2111 debug2("channel %d: gc: user detached", c->self);
2112 }
2113 if (!chan_is_dead(c, 1))
2114 return;
2115 debug2("channel %d: garbage collecting", c->self);
2116 channel_free(c);
2117 }
2118
2119 static void
2120 channel_handler(chan_fn *ftab[], fd_set *readset, fd_set *writeset,
2121 time_t *unpause_secs)
2122 {
2123 static int did_init = 0;
2124 u_int i, oalloc;
2125 Channel *c;
2126 time_t now;
2127
2128 if (!did_init) {
2129 channel_handler_init();
2130 did_init = 1;
2131 }
2132 now = monotime();
2133 if (unpause_secs != NULL)
2134 *unpause_secs = 0;
2135 for (i = 0, oalloc = channels_alloc; i < oalloc; i++) {
2136 c = channels[i];
2137 if (c == NULL)
2138 continue;
2139 if (c->delayed) {
2140 if (ftab == channel_pre)
2141 c->delayed = 0;
2142 else
2143 continue;
2144 }
2145 if (ftab[c->type] != NULL) {
2146 /*
2147 * Run handlers that are not paused.
2148 */
2149 if (c->notbefore <= now)
2150 (*ftab[c->type])(c, readset, writeset);
2151 else if (unpause_secs != NULL) {
2152 /*
2153 * Collect the time that the earliest
2154 * channel comes off pause.
2155 */
2156 debug3("%s: chan %d: skip for %d more seconds",
2157 __func__, c->self,
2158 (int)(c->notbefore - now));
2159 if (*unpause_secs == 0 ||
2160 (c->notbefore - now) < *unpause_secs)
2161 *unpause_secs = c->notbefore - now;
2162 }
2163 }
2164 channel_garbage_collect(c);
2165 }
2166 if (unpause_secs != NULL && *unpause_secs != 0)
2167 debug3("%s: first channel unpauses in %d seconds",
2168 __func__, (int)*unpause_secs);
2169 }
2170
2171 /*
2172 * Allocate/update select bitmasks and add any bits relevant to channels in
2173 * select bitmasks.
2174 */
2175 void
2176 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
2177 u_int *nallocp, time_t *minwait_secs, int rekeying)
2178 {
2179 u_int n, sz, nfdset;
2180
2181 n = MAX(*maxfdp, channel_max_fd);
2182
2183 nfdset = howmany(n+1, NFDBITS);
2184 /* Explicitly test here, because xrealloc isn't always called */
2185 if (nfdset && SIZE_T_MAX / nfdset < sizeof(fd_mask))
2186 fatal("channel_prepare_select: max_fd (%d) is too large", n);
2187 sz = nfdset * sizeof(fd_mask);
2188
2189 /* perhaps check sz < nalloc/2 and shrink? */
2190 if (*readsetp == NULL || sz > *nallocp) {
2191 *readsetp = xrealloc(*readsetp, nfdset, sizeof(fd_mask));
2192 *writesetp = xrealloc(*writesetp, nfdset, sizeof(fd_mask));
2193 *nallocp = sz;
2194 }
2195 *maxfdp = n;
2196 memset(*readsetp, 0, sz);
2197 memset(*writesetp, 0, sz);
2198
2199 if (!rekeying)
2200 channel_handler(channel_pre, *readsetp, *writesetp,
2201 minwait_secs);
2202 }
2203
2204 /*
2205 * After select, perform any appropriate operations for channels which have
2206 * events pending.
2207 */
2208 void
2209 channel_after_select(fd_set *readset, fd_set *writeset)
2210 {
2211 channel_handler(channel_post, readset, writeset, NULL);
2212 }
2213
2214
2215 /* If there is data to send to the connection, enqueue some of it now. */
2216 void
2217 channel_output_poll(void)
2218 {
2219 Channel *c;
2220 u_int i, len;
2221
2222 for (i = 0; i < channels_alloc; i++) {
2223 c = channels[i];
2224 if (c == NULL)
2225 continue;
2226
2227 /*
2228 * We are only interested in channels that can have buffered
2229 * incoming data.
2230 */
2231 if (compat13) {
2232 if (c->type != SSH_CHANNEL_OPEN &&
2233 c->type != SSH_CHANNEL_INPUT_DRAINING)
2234 continue;
2235 } else {
2236 if (c->type != SSH_CHANNEL_OPEN)
2237 continue;
2238 }
2239 if (compat20 &&
2240 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
2241 /* XXX is this true? */
2242 debug3("channel %d: will not send data after close", c->self);
2243 continue;
2244 }
2245
2246 /* Get the amount of buffered data for this channel. */
2247 if ((c->istate == CHAN_INPUT_OPEN ||
2248 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
2249 (len = buffer_len(&c->input)) > 0) {
2250 if (c->datagram) {
2251 if (len > 0) {
2252 u_char *data;
2253 u_int dlen;
2254
2255 data = buffer_get_string(&c->input,
2256 &dlen);
2257 if (dlen > c->remote_window ||
2258 dlen > c->remote_maxpacket) {
2259 debug("channel %d: datagram "
2260 "too big for channel",
2261 c->self);
2262 free(data);
2263 continue;
2264 }
2265 packet_start(SSH2_MSG_CHANNEL_DATA);
2266 packet_put_int(c->remote_id);
2267 packet_put_string(data, dlen);
2268 packet_send();
2269 c->remote_window -= dlen + 4;
2270 free(data);
2271 }
2272 continue;
2273 }
2274 /*
2275 * Send some data for the other side over the secure
2276 * connection.
2277 */
2278 if (compat20) {
2279 if (len > c->remote_window)
2280 len = c->remote_window;
2281 if (len > c->remote_maxpacket)
2282 len = c->remote_maxpacket;
2283 } else {
2284 if (packet_is_interactive()) {
2285 if (len > 1024)
2286 len = 512;
2287 } else {
2288 /* Keep the packets at reasonable size. */
2289 if (len > packet_get_maxsize()/2)
2290 len = packet_get_maxsize()/2;
2291 }
2292 }
2293 if (len > 0) {
2294 packet_start(compat20 ?
2295 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
2296 packet_put_int(c->remote_id);
2297 packet_put_string(buffer_ptr(&c->input), len);
2298 packet_send();
2299 buffer_consume(&c->input, len);
2300 c->remote_window -= len;
2301 }
2302 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
2303 if (compat13)
2304 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
2305 /*
2306 * input-buffer is empty and read-socket shutdown:
2307 * tell peer, that we will not send more data: send IEOF.
2308 * hack for extended data: delay EOF if EFD still in use.
2309 */
2310 if (CHANNEL_EFD_INPUT_ACTIVE(c))
2311 debug2("channel %d: ibuf_empty delayed efd %d/(%d)",
2312 c->self, c->efd, buffer_len(&c->extended));
2313 else
2314 chan_ibuf_empty(c);
2315 }
2316 /* Send extended data, i.e. stderr */
2317 if (compat20 &&
2318 !(c->flags & CHAN_EOF_SENT) &&
2319 c->remote_window > 0 &&
2320 (len = buffer_len(&c->extended)) > 0 &&
2321 c->extended_usage == CHAN_EXTENDED_READ) {
2322 debug2("channel %d: rwin %u elen %u euse %d",
2323 c->self, c->remote_window, buffer_len(&c->extended),
2324 c->extended_usage);
2325 if (len > c->remote_window)
2326 len = c->remote_window;
2327 if (len > c->remote_maxpacket)
2328 len = c->remote_maxpacket;
2329 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
2330 packet_put_int(c->remote_id);
2331 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
2332 packet_put_string(buffer_ptr(&c->extended), len);
2333 packet_send();
2334 buffer_consume(&c->extended, len);
2335 c->remote_window -= len;
2336 debug2("channel %d: sent ext data %d", c->self, len);
2337 }
2338 }
2339 }
2340
2341
2342 /* -- protocol input */
2343
2344 /* ARGSUSED */
2345 void
2346 channel_input_data(int type, u_int32_t seq, void *ctxt)
2347 {
2348 int id;
2349 const u_char *data;
2350 u_int data_len, win_len;
2351 Channel *c;
2352
2353 /* Get the channel number and verify it. */
2354 id = packet_get_int();
2355 c = channel_lookup(id);
2356 if (c == NULL)
2357 packet_disconnect("Received data for nonexistent channel %d.", id);
2358
2359 /* Ignore any data for non-open channels (might happen on close) */
2360 if (c->type != SSH_CHANNEL_OPEN &&
2361 c->type != SSH_CHANNEL_X11_OPEN)
2362 return;
2363
2364 /* Get the data. */
2365 data = packet_get_string_ptr(&data_len);
2366 win_len = data_len;
2367 if (c->datagram)
2368 win_len += 4; /* string length header */
2369
2370 /*
2371 * Ignore data for protocol > 1.3 if output end is no longer open.
2372 * For protocol 2 the sending side is reducing its window as it sends
2373 * data, so we must 'fake' consumption of the data in order to ensure
2374 * that window updates are sent back. Otherwise the connection might
2375 * deadlock.
2376 */
2377 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) {
2378 if (compat20) {
2379 c->local_window -= win_len;
2380 c->local_consumed += win_len;
2381 }
2382 return;
2383 }
2384
2385 if (compat20) {
2386 if (win_len > c->local_maxpacket) {
2387 logit("channel %d: rcvd big packet %d, maxpack %d",
2388 c->self, win_len, c->local_maxpacket);
2389 }
2390 if (win_len > c->local_window) {
2391 logit("channel %d: rcvd too much data %d, win %d",
2392 c->self, win_len, c->local_window);
2393 return;
2394 }
2395 c->local_window -= win_len;
2396 }
2397 if (c->datagram)
2398 buffer_put_string(&c->output, data, data_len);
2399 else
2400 buffer_append(&c->output, data, data_len);
2401 packet_check_eom();
2402 }
2403
2404 /* ARGSUSED */
2405 void
2406 channel_input_extended_data(int type, u_int32_t seq, void *ctxt)
2407 {
2408 int id;
2409 char *data;
2410 u_int data_len, tcode;
2411 Channel *c;
2412
2413 /* Get the channel number and verify it. */
2414 id = packet_get_int();
2415 c = channel_lookup(id);
2416
2417 if (c == NULL)
2418 packet_disconnect("Received extended_data for bad channel %d.", id);
2419 if (c->type != SSH_CHANNEL_OPEN) {
2420 logit("channel %d: ext data for non open", id);
2421 return;
2422 }
2423 if (c->flags & CHAN_EOF_RCVD) {
2424 if (datafellows & SSH_BUG_EXTEOF)
2425 debug("channel %d: accepting ext data after eof", id);
2426 else
2427 packet_disconnect("Received extended_data after EOF "
2428 "on channel %d.", id);
2429 }
2430 tcode = packet_get_int();
2431 if (c->efd == -1 ||
2432 c->extended_usage != CHAN_EXTENDED_WRITE ||
2433 tcode != SSH2_EXTENDED_DATA_STDERR) {
2434 logit("channel %d: bad ext data", c->self);
2435 return;
2436 }
2437 data = packet_get_string(&data_len);
2438 packet_check_eom();
2439 if (data_len > c->local_window) {
2440 logit("channel %d: rcvd too much extended_data %d, win %d",
2441 c->self, data_len, c->local_window);
2442 free(data);
2443 return;
2444 }
2445 debug2("channel %d: rcvd ext data %d", c->self, data_len);
2446 c->local_window -= data_len;
2447 buffer_append(&c->extended, data, data_len);
2448 free(data);
2449 }
2450
2451 /* ARGSUSED */
2452 void
2453 channel_input_ieof(int type, u_int32_t seq, void *ctxt)
2454 {
2455 int id;
2456 Channel *c;
2457
2458 id = packet_get_int();
2459 packet_check_eom();
2460 c = channel_lookup(id);
2461 if (c == NULL)
2462 packet_disconnect("Received ieof for nonexistent channel %d.", id);
2463 chan_rcvd_ieof(c);
2464
2465 /* XXX force input close */
2466 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) {
2467 debug("channel %d: FORCE input drain", c->self);
2468 c->istate = CHAN_INPUT_WAIT_DRAIN;
2469 if (buffer_len(&c->input) == 0)
2470 chan_ibuf_empty(c);
2471 }
2472
2473 }
2474
2475 /* ARGSUSED */
2476 void
2477 channel_input_close(int type, u_int32_t seq, void *ctxt)
2478 {
2479 int id;
2480 Channel *c;
2481
2482 id = packet_get_int();
2483 packet_check_eom();
2484 c = channel_lookup(id);
2485 if (c == NULL)
2486 packet_disconnect("Received close for nonexistent channel %d.", id);
2487
2488 /*
2489 * Send a confirmation that we have closed the channel and no more
2490 * data is coming for it.
2491 */
2492 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
2493 packet_put_int(c->remote_id);
2494 packet_send();
2495
2496 /*
2497 * If the channel is in closed state, we have sent a close request,
2498 * and the other side will eventually respond with a confirmation.
2499 * Thus, we cannot free the channel here, because then there would be
2500 * no-one to receive the confirmation. The channel gets freed when
2501 * the confirmation arrives.
2502 */
2503 if (c->type != SSH_CHANNEL_CLOSED) {
2504 /*
2505 * Not a closed channel - mark it as draining, which will
2506 * cause it to be freed later.
2507 */
2508 buffer_clear(&c->input);
2509 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
2510 }
2511 }
2512
2513 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
2514 /* ARGSUSED */
2515 void
2516 channel_input_oclose(int type, u_int32_t seq, void *ctxt)
2517 {
2518 int id = packet_get_int();
2519 Channel *c = channel_lookup(id);
2520
2521 packet_check_eom();
2522 if (c == NULL)
2523 packet_disconnect("Received oclose for nonexistent channel %d.", id);
2524 chan_rcvd_oclose(c);
2525 }
2526
2527 /* ARGSUSED */
2528 void
2529 channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt)
2530 {
2531 int id = packet_get_int();
2532 Channel *c = channel_lookup(id);
2533
2534 packet_check_eom();
2535 if (c == NULL)
2536 packet_disconnect("Received close confirmation for "
2537 "out-of-range channel %d.", id);
2538 if (c->type != SSH_CHANNEL_CLOSED && c->type != SSH_CHANNEL_ABANDONED)
2539 packet_disconnect("Received close confirmation for "
2540 "non-closed channel %d (type %d).", id, c->type);
2541 channel_free(c);
2542 }
2543
2544 /* ARGSUSED */
2545 void
2546 channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt)
2547 {
2548 int id, remote_id;
2549 Channel *c;
2550
2551 id = packet_get_int();
2552 c = channel_lookup(id);
2553
2554 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2555 packet_disconnect("Received open confirmation for "
2556 "non-opening channel %d.", id);
2557 remote_id = packet_get_int();
2558 /* Record the remote channel number and mark that the channel is now open. */
2559 c->remote_id = remote_id;
2560 c->type = SSH_CHANNEL_OPEN;
2561
2562 if (compat20) {
2563 c->remote_window = packet_get_int();
2564 c->remote_maxpacket = packet_get_int();
2565 if (c->open_confirm) {
2566 debug2("callback start");
2567 c->open_confirm(c->self, 1, c->open_confirm_ctx);
2568 debug2("callback done");
2569 }
2570 debug2("channel %d: open confirm rwindow %u rmax %u", c->self,
2571 c->remote_window, c->remote_maxpacket);
2572 }
2573 packet_check_eom();
2574 }
2575
2576 static char *
2577 reason2txt(int reason)
2578 {
2579 switch (reason) {
2580 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
2581 return "administratively prohibited";
2582 case SSH2_OPEN_CONNECT_FAILED:
2583 return "connect failed";
2584 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
2585 return "unknown channel type";
2586 case SSH2_OPEN_RESOURCE_SHORTAGE:
2587 return "resource shortage";
2588 }
2589 return "unknown reason";
2590 }
2591
2592 /* ARGSUSED */
2593 void
2594 channel_input_open_failure(int type, u_int32_t seq, void *ctxt)
2595 {
2596 int id, reason;
2597 char *msg = NULL, *lang = NULL;
2598 Channel *c;
2599
2600 id = packet_get_int();
2601 c = channel_lookup(id);
2602
2603 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2604 packet_disconnect("Received open failure for "
2605 "non-opening channel %d.", id);
2606 if (compat20) {
2607 reason = packet_get_int();
2608 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
2609 msg = packet_get_string(NULL);
2610 lang = packet_get_string(NULL);
2611 }
2612 logit("channel %d: open failed: %s%s%s", id,
2613 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
2614 free(msg);
2615 free(lang);
2616 if (c->open_confirm) {
2617 debug2("callback start");
2618 c->open_confirm(c->self, 0, c->open_confirm_ctx);
2619 debug2("callback done");
2620 }
2621 }
2622 packet_check_eom();
2623 /* Schedule the channel for cleanup/deletion. */
2624 chan_mark_dead(c);
2625 }
2626
2627 /* ARGSUSED */
2628 void
2629 channel_input_window_adjust(int type, u_int32_t seq, void *ctxt)
2630 {
2631 Channel *c;
2632 int id;
2633 u_int adjust;
2634
2635 if (!compat20)
2636 return;
2637
2638 /* Get the channel number and verify it. */
2639 id = packet_get_int();
2640 c = channel_lookup(id);
2641
2642 if (c == NULL) {
2643 logit("Received window adjust for non-open channel %d.", id);
2644 return;
2645 }
2646 adjust = packet_get_int();
2647 packet_check_eom();
2648 debug2("channel %d: rcvd adjust %u", id, adjust);
2649 c->remote_window += adjust;
2650 }
2651
2652 /* ARGSUSED */
2653 void
2654 channel_input_port_open(int type, u_int32_t seq, void *ctxt)
2655 {
2656 Channel *c = NULL;
2657 u_short host_port;
2658 char *host, *originator_string;
2659 int remote_id;
2660
2661 remote_id = packet_get_int();
2662 host = packet_get_string(NULL);
2663 host_port = packet_get_int();
2664
2665 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2666 originator_string = packet_get_string(NULL);
2667 } else {
2668 originator_string = xstrdup("unknown (remote did not supply name)");
2669 }
2670 packet_check_eom();
2671 c = channel_connect_to_port(host, host_port,
2672 "connected socket", originator_string);
2673 free(originator_string);
2674 free(host);
2675 if (c == NULL) {
2676 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2677 packet_put_int(remote_id);
2678 packet_send();
2679 } else
2680 c->remote_id = remote_id;
2681 }
2682
2683 /* ARGSUSED */
2684 void
2685 channel_input_status_confirm(int type, u_int32_t seq, void *ctxt)
2686 {
2687 Channel *c;
2688 struct channel_confirm *cc;
2689 int id;
2690
2691 /* Reset keepalive timeout */
2692 packet_set_alive_timeouts(0);
2693
2694 id = packet_get_int();
2695 packet_check_eom();
2696
2697 debug2("channel_input_status_confirm: type %d id %d", type, id);
2698
2699 if ((c = channel_lookup(id)) == NULL) {
2700 logit("channel_input_status_confirm: %d: unknown", id);
2701 return;
2702 }
2703 ;
2704 if ((cc = TAILQ_FIRST(&c->status_confirms)) == NULL)
2705 return;
2706 cc->cb(type, c, cc->ctx);
2707 TAILQ_REMOVE(&c->status_confirms, cc, entry);
2708 explicit_bzero(cc, sizeof(*cc));
2709 free(cc);
2710 }
2711
2712 /* -- tcp forwarding */
2713
2714 void
2715 channel_set_af(int af)
2716 {
2717 IPv4or6 = af;
2718 }
2719
2720
2721 /*
2722 * Determine whether or not a port forward listens to loopback, the
2723 * specified address or wildcard. On the client, a specified bind
2724 * address will always override gateway_ports. On the server, a
2725 * gateway_ports of 1 (``yes'') will override the client's specification
2726 * and force a wildcard bind, whereas a value of 2 (``clientspecified'')
2727 * will bind to whatever address the client asked for.
2728 *
2729 * Special-case listen_addrs are:
2730 *
2731 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR
2732 * "" (empty string), "*" -> wildcard v4/v6
2733 * "localhost" -> loopback v4/v6
2734 * "127.0.0.1" / "::1" -> accepted even if gateway_ports isn't set
2735 */
2736 static const char *
2737 channel_fwd_bind_addr(const char *listen_addr, int *wildcardp,
2738 int is_client, struct ForwardOptions *fwd_opts)
2739 {
2740 const char *addr = NULL;
2741 int wildcard = 0;
2742
2743 if (listen_addr == NULL) {
2744 /* No address specified: default to gateway_ports setting */
2745 if (fwd_opts->gateway_ports)
2746 wildcard = 1;
2747 } else if (fwd_opts->gateway_ports || is_client) {
2748 if (((datafellows & SSH_OLD_FORWARD_ADDR) &&
2749 strcmp(listen_addr, "0.0.0.0") == 0 && is_client == 0) ||
2750 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 ||
2751 (!is_client && fwd_opts->gateway_ports == 1)) {
2752 wildcard = 1;
2753 /*
2754 * Notify client if they requested a specific listen
2755 * address and it was overridden.
2756 */
2757 if (*listen_addr != '\0' &&
2758 strcmp(listen_addr, "0.0.0.0") != 0 &&
2759 strcmp(listen_addr, "*") != 0) {
2760 packet_send_debug("Forwarding listen address "
2761 "\"%s\" overridden by server "
2762 "GatewayPorts", listen_addr);
2763 }
2764 } else if (strcmp(listen_addr, "localhost") != 0 ||
2765 strcmp(listen_addr, "127.0.0.1") == 0 ||
2766 strcmp(listen_addr, "::1") == 0) {
2767 /* Accept localhost address when GatewayPorts=yes */
2768 addr = listen_addr;
2769 }
2770 } else if (strcmp(listen_addr, "127.0.0.1") == 0 ||
2771 strcmp(listen_addr, "::1") == 0) {
2772 /*
2773 * If a specific IPv4/IPv6 localhost address has been
2774 * requested then accept it even if gateway_ports is in
2775 * effect. This allows the client to prefer IPv4 or IPv6.
2776 */
2777 addr = listen_addr;
2778 }
2779 if (wildcardp != NULL)
2780 *wildcardp = wildcard;
2781 return addr;
2782 }
2783
2784 static int
2785 channel_setup_fwd_listener_tcpip(int type, struct Forward *fwd,
2786 int *allocated_listen_port, struct ForwardOptions *fwd_opts)
2787 {
2788 Channel *c;
2789 int sock, r, success = 0, wildcard = 0, is_client;
2790 struct addrinfo hints, *ai, *aitop;
2791 const char *host, *addr;
2792 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2793 in_port_t *lport_p;
2794
2795 host = (type == SSH_CHANNEL_RPORT_LISTENER) ?
2796 fwd->listen_host : fwd->connect_host;
2797 is_client = (type == SSH_CHANNEL_PORT_LISTENER);
2798
2799 if (host == NULL) {
2800 error("No forward host name.");
2801 return 0;
2802 }
2803 if (strlen(host) >= NI_MAXHOST) {
2804 error("Forward host name too long.");
2805 return 0;
2806 }
2807
2808 /* Determine the bind address, cf. channel_fwd_bind_addr() comment */
2809 addr = channel_fwd_bind_addr(fwd->listen_host, &wildcard,
2810 is_client, fwd_opts);
2811 debug3("%s: type %d wildcard %d addr %s", __func__,
2812 type, wildcard, (addr == NULL) ? "NULL" : addr);
2813
2814 /*
2815 * getaddrinfo returns a loopback address if the hostname is
2816 * set to NULL and hints.ai_flags is not AI_PASSIVE
2817 */
2818 memset(&hints, 0, sizeof(hints));
2819 hints.ai_family = IPv4or6;
2820 hints.ai_flags = wildcard ? AI_PASSIVE : 0;
2821 hints.ai_socktype = SOCK_STREAM;
2822 snprintf(strport, sizeof strport, "%d", fwd->listen_port);
2823 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) {
2824 if (addr == NULL) {
2825 /* This really shouldn't happen */
2826 packet_disconnect("getaddrinfo: fatal error: %s",
2827 ssh_gai_strerror(r));
2828 } else {
2829 error("%s: getaddrinfo(%.64s): %s", __func__, addr,
2830 ssh_gai_strerror(r));
2831 }
2832 return 0;
2833 }
2834 if (allocated_listen_port != NULL)
2835 *allocated_listen_port = 0;
2836 for (ai = aitop; ai; ai = ai->ai_next) {
2837 switch (ai->ai_family) {
2838 case AF_INET:
2839 lport_p = &((struct sockaddr_in *)ai->ai_addr)->
2840 sin_port;
2841 break;
2842 case AF_INET6:
2843 lport_p = &((struct sockaddr_in6 *)ai->ai_addr)->
2844 sin6_port;
2845 break;
2846 default:
2847 continue;
2848 }
2849 /*
2850 * If allocating a port for -R forwards, then use the
2851 * same port for all address families.
2852 */
2853 if (type == SSH_CHANNEL_RPORT_LISTENER && fwd->listen_port == 0 &&
2854 allocated_listen_port != NULL && *allocated_listen_port > 0)
2855 *lport_p = htons(*allocated_listen_port);
2856
2857 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2858 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2859 error("%s: getnameinfo failed", __func__);
2860 continue;
2861 }
2862 /* Create a port to listen for the host. */
2863 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2864 if (sock < 0) {
2865 /* this is no error since kernel may not support ipv6 */
2866 verbose("socket: %.100s", strerror(errno));
2867 continue;
2868 }
2869
2870 channel_set_reuseaddr(sock);
2871 if (ai->ai_family == AF_INET6)
2872 sock_set_v6only(sock);
2873
2874 debug("Local forwarding listening on %s port %s.",
2875 ntop, strport);
2876
2877 /* Bind the socket to the address. */
2878 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2879 /* address can be in use ipv6 address is already bound */
2880 if (!ai->ai_next)
2881 error("bind: %.100s", strerror(errno));
2882 else
2883 verbose("bind: %.100s", strerror(errno));
2884
2885 close(sock);
2886 continue;
2887 }
2888 /* Start listening for connections on the socket. */
2889 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2890 error("listen: %.100s", strerror(errno));
2891 close(sock);
2892 continue;
2893 }
2894
2895 /*
2896 * fwd->listen_port == 0 requests a dynamically allocated port -
2897 * record what we got.
2898 */
2899 if (type == SSH_CHANNEL_RPORT_LISTENER && fwd->listen_port == 0 &&
2900 allocated_listen_port != NULL &&
2901 *allocated_listen_port == 0) {
2902 *allocated_listen_port = get_sock_port(sock, 1);
2903 debug("Allocated listen port %d",
2904 *allocated_listen_port);
2905 }
2906
2907 /* Allocate a channel number for the socket. */
2908 c = channel_new("port listener", type, sock, sock, -1,
2909 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2910 0, "port listener", 1);
2911 c->path = xstrdup(host);
2912 c->host_port = fwd->connect_port;
2913 c->listening_addr = addr == NULL ? NULL : xstrdup(addr);
2914 if (fwd->listen_port == 0 && allocated_listen_port != NULL &&
2915 !(datafellows & SSH_BUG_DYNAMIC_RPORT))
2916 c->listening_port = *allocated_listen_port;
2917 else
2918 c->listening_port = fwd->listen_port;
2919 success = 1;
2920 }
2921 if (success == 0)
2922 error("%s: cannot listen to port: %d", __func__,
2923 fwd->listen_port);
2924 freeaddrinfo(aitop);
2925 return success;
2926 }
2927
2928 static int
2929 channel_setup_fwd_listener_streamlocal(int type, struct Forward *fwd,
2930 struct ForwardOptions *fwd_opts)
2931 {
2932 struct sockaddr_un sunaddr;
2933 const char *path;
2934 Channel *c;
2935 int port, sock;
2936 mode_t omask;
2937
2938 switch (type) {
2939 case SSH_CHANNEL_UNIX_LISTENER:
2940 if (fwd->connect_path != NULL) {
2941 if (strlen(fwd->connect_path) > sizeof(sunaddr.sun_path)) {
2942 error("Local connecting path too long: %s",
2943 fwd->connect_path);
2944 return 0;
2945 }
2946 path = fwd->connect_path;
2947 port = PORT_STREAMLOCAL;
2948 } else {
2949 if (fwd->connect_host == NULL) {
2950 error("No forward host name.");
2951 return 0;
2952 }
2953 if (strlen(fwd->connect_host) >= NI_MAXHOST) {
2954 error("Forward host name too long.");
2955 return 0;
2956 }
2957 path = fwd->connect_host;
2958 port = fwd->connect_port;
2959 }
2960 break;
2961 case SSH_CHANNEL_RUNIX_LISTENER:
2962 path = fwd->listen_path;
2963 port = PORT_STREAMLOCAL;
2964 break;
2965 default:
2966 error("%s: unexpected channel type %d", __func__, type);
2967 return 0;
2968 }
2969
2970 if (fwd->listen_path == NULL) {
2971 error("No forward path name.");
2972 return 0;
2973 }
2974 if (strlen(fwd->listen_path) > sizeof(sunaddr.sun_path)) {
2975 error("Local listening path too long: %s", fwd->listen_path);
2976 return 0;
2977 }
2978
2979 debug3("%s: type %d path %s", __func__, type, fwd->listen_path);
2980
2981 /* Start a Unix domain listener. */
2982 omask = umask(fwd_opts->streamlocal_bind_mask);
2983 sock = unix_listener(fwd->listen_path, SSH_LISTEN_BACKLOG,
2984 fwd_opts->streamlocal_bind_unlink);
2985 umask(omask);
2986 if (sock < 0)
2987 return 0;
2988
2989 debug("Local forwarding listening on path %s.", fwd->listen_path);
2990
2991 /* Allocate a channel number for the socket. */
2992 c = channel_new("unix listener", type, sock, sock, -1,
2993 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2994 0, "unix listener", 1);
2995 c->path = xstrdup(path);
2996 c->host_port = port;
2997 c->listening_port = PORT_STREAMLOCAL;
2998 c->listening_addr = xstrdup(fwd->listen_path);
2999 return 1;
3000 }
3001
3002 static int
3003 channel_cancel_rport_listener_tcpip(const char *host, u_short port)
3004 {
3005 u_int i;
3006 int found = 0;
3007
3008 for (i = 0; i < channels_alloc; i++) {
3009 Channel *c = channels[i];
3010 if (c == NULL || c->type != SSH_CHANNEL_RPORT_LISTENER)
3011 continue;
3012 if (strcmp(c->path, host) == 0 && c->listening_port == port) {
3013 debug2("%s: close channel %d", __func__, i);
3014 channel_free(c);
3015 found = 1;
3016 }
3017 }
3018
3019 return (found);
3020 }
3021
3022 static int
3023 channel_cancel_rport_listener_streamlocal(const char *path)
3024 {
3025 u_int i;
3026 int found = 0;
3027
3028 for (i = 0; i < channels_alloc; i++) {
3029 Channel *c = channels[i];
3030 if (c == NULL || c->type != SSH_CHANNEL_RUNIX_LISTENER)
3031 continue;
3032 if (c->path == NULL)
3033 continue;
3034 if (strcmp(c->path, path) == 0) {
3035 debug2("%s: close channel %d", __func__, i);
3036 channel_free(c);
3037 found = 1;
3038 }
3039 }
3040
3041 return (found);
3042 }
3043
3044 int
3045 channel_cancel_rport_listener(struct Forward *fwd)
3046 {
3047 if (fwd->listen_path != NULL)
3048 return channel_cancel_rport_listener_streamlocal(fwd->listen_path);
3049 else
3050 return channel_cancel_rport_listener_tcpip(fwd->listen_host, fwd->listen_port);
3051 }
3052
3053 static int
3054 channel_cancel_lport_listener_tcpip(const char *lhost, u_short lport,
3055 int cport, struct ForwardOptions *fwd_opts)
3056 {
3057 u_int i;
3058 int found = 0;
3059 const char *addr = channel_fwd_bind_addr(lhost, NULL, 1, fwd_opts);
3060
3061 for (i = 0; i < channels_alloc; i++) {
3062 Channel *c = channels[i];
3063 if (c == NULL || c->type != SSH_CHANNEL_PORT_LISTENER)
3064 continue;
3065 if (c->listening_port != lport)
3066 continue;
3067 if (cport == CHANNEL_CANCEL_PORT_STATIC) {
3068 /* skip dynamic forwardings */
3069 if (c->host_port == 0)
3070 continue;
3071 } else {
3072 if (c->host_port != cport)
3073 continue;
3074 }
3075 if ((c->listening_addr == NULL && addr != NULL) ||
3076 (c->listening_addr != NULL && addr == NULL))
3077 continue;
3078 if (addr == NULL || strcmp(c->listening_addr, addr) == 0) {
3079 debug2("%s: close channel %d", __func__, i);
3080 channel_free(c);
3081 found = 1;
3082 }
3083 }
3084
3085 return (found);
3086 }
3087
3088 static int
3089 channel_cancel_lport_listener_streamlocal(const char *path)
3090 {
3091 u_int i;
3092 int found = 0;
3093
3094 if (path == NULL) {
3095 error("%s: no path specified.", __func__);
3096 return 0;
3097 }
3098
3099 for (i = 0; i < channels_alloc; i++) {
3100 Channel *c = channels[i];
3101 if (c == NULL || c->type != SSH_CHANNEL_UNIX_LISTENER)
3102 continue;
3103 if (c->listening_addr == NULL)
3104 continue;
3105 if (strcmp(c->listening_addr, path) == 0) {
3106 debug2("%s: close channel %d", __func__, i);
3107 channel_free(c);
3108 found = 1;
3109 }
3110 }
3111
3112 return (found);
3113 }
3114
3115 int
3116 channel_cancel_lport_listener(struct Forward *fwd, int cport, struct ForwardOptions *fwd_opts)
3117 {
3118 if (fwd->listen_path != NULL)
3119 return channel_cancel_lport_listener_streamlocal(fwd->listen_path);
3120 else
3121 return channel_cancel_lport_listener_tcpip(fwd->listen_host, fwd->listen_port, cport, fwd_opts);
3122 }
3123
3124 /* protocol local port fwd, used by ssh (and sshd in v1) */
3125 int
3126 channel_setup_local_fwd_listener(struct Forward *fwd, struct ForwardOptions *fwd_opts)
3127 {
3128 if (fwd->listen_path != NULL) {
3129 return channel_setup_fwd_listener_streamlocal(
3130 SSH_CHANNEL_UNIX_LISTENER, fwd, fwd_opts);
3131 } else {
3132 return channel_setup_fwd_listener_tcpip(SSH_CHANNEL_PORT_LISTENER,
3133 fwd, NULL, fwd_opts);
3134 }
3135 }
3136
3137 /* protocol v2 remote port fwd, used by sshd */
3138 int
3139 channel_setup_remote_fwd_listener(struct Forward *fwd,
3140 int *allocated_listen_port, struct ForwardOptions *fwd_opts)
3141 {
3142 if (fwd->listen_path != NULL) {
3143 return channel_setup_fwd_listener_streamlocal(
3144 SSH_CHANNEL_RUNIX_LISTENER, fwd, fwd_opts);
3145 } else {
3146 return channel_setup_fwd_listener_tcpip(
3147 SSH_CHANNEL_RPORT_LISTENER, fwd, allocated_listen_port,
3148 fwd_opts);
3149 }
3150 }
3151
3152 /*
3153 * Translate the requested rfwd listen host to something usable for
3154 * this server.
3155 */
3156 static const char *
3157 channel_rfwd_bind_host(const char *listen_host)
3158 {
3159 if (listen_host == NULL) {
3160 if (datafellows & SSH_BUG_RFWD_ADDR)
3161 return "127.0.0.1";
3162 else
3163 return "localhost";
3164 } else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0) {
3165 if (datafellows & SSH_BUG_RFWD_ADDR)
3166 return "0.0.0.0";
3167 else
3168 return "";
3169 } else
3170 return listen_host;
3171 }
3172
3173 /*
3174 * Initiate forwarding of connections to port "port" on remote host through
3175 * the secure channel to host:port from local side.
3176 * Returns handle (index) for updating the dynamic listen port with
3177 * channel_update_permitted_opens().
3178 */
3179 int
3180 channel_request_remote_forwarding(struct Forward *fwd)
3181 {
3182 int type, success = 0, idx = -1;
3183
3184 /* Send the forward request to the remote side. */
3185 if (compat20) {
3186 packet_start(SSH2_MSG_GLOBAL_REQUEST);
3187 if (fwd->listen_path != NULL) {
3188 packet_put_cstring("streamlocal-forward@openssh.com");
3189 packet_put_char(1); /* boolean: want reply */
3190 packet_put_cstring(fwd->listen_path);
3191 } else {
3192 packet_put_cstring("tcpip-forward");
3193 packet_put_char(1); /* boolean: want reply */
3194 packet_put_cstring(channel_rfwd_bind_host(fwd->listen_host));
3195 packet_put_int(fwd->listen_port);
3196 }
3197 packet_send();
3198 packet_write_wait();
3199 /* Assume that server accepts the request */
3200 success = 1;
3201 } else if (fwd->listen_path == NULL) {
3202 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
3203 packet_put_int(fwd->listen_port);
3204 packet_put_cstring(fwd->connect_host);
3205 packet_put_int(fwd->connect_port);
3206 packet_send();
3207 packet_write_wait();
3208
3209 /* Wait for response from the remote side. */
3210 type = packet_read();
3211 switch (type) {
3212 case SSH_SMSG_SUCCESS:
3213 success = 1;
3214 break;
3215 case SSH_SMSG_FAILURE:
3216 break;
3217 default:
3218 /* Unknown packet */
3219 packet_disconnect("Protocol error for port forward request:"
3220 "received packet type %d.", type);
3221 }
3222 } else {
3223 logit("Warning: Server does not support remote stream local forwarding.");
3224 }
3225 if (success) {
3226 /* Record that connection to this host/port is permitted. */
3227 permitted_opens = xrealloc(permitted_opens,
3228 num_permitted_opens + 1, sizeof(*permitted_opens));
3229 idx = num_permitted_opens++;
3230 if (fwd->connect_path != NULL) {
3231 permitted_opens[idx].host_to_connect =
3232 xstrdup(fwd->connect_path);
3233 permitted_opens[idx].port_to_connect =
3234 PORT_STREAMLOCAL;
3235 } else {
3236 permitted_opens[idx].host_to_connect =
3237 xstrdup(fwd->connect_host);
3238 permitted_opens[idx].port_to_connect =
3239 fwd->connect_port;
3240 }
3241 if (fwd->listen_path != NULL) {
3242 permitted_opens[idx].listen_host = NULL;
3243 permitted_opens[idx].listen_path =
3244 xstrdup(fwd->listen_path);
3245 permitted_opens[idx].listen_port = PORT_STREAMLOCAL;
3246 } else {
3247 permitted_opens[idx].listen_host =
3248 fwd->listen_host ? xstrdup(fwd->listen_host) : NULL;
3249 permitted_opens[idx].listen_path = NULL;
3250 permitted_opens[idx].listen_port = fwd->listen_port;
3251 }
3252 }
3253 return (idx);
3254 }
3255
3256 static int
3257 open_match(ForwardPermission *allowed_open, const char *requestedhost,
3258 int requestedport)
3259 {
3260 if (allowed_open->host_to_connect == NULL)
3261 return 0;
3262 if (allowed_open->port_to_connect != FWD_PERMIT_ANY_PORT &&
3263 allowed_open->port_to_connect != requestedport)
3264 return 0;
3265 if (strcmp(allowed_open->host_to_connect, requestedhost) != 0)
3266 return 0;
3267 return 1;
3268 }
3269
3270 /*
3271 * Note that in the listen host/port case
3272 * we don't support FWD_PERMIT_ANY_PORT and
3273 * need to translate between the configured-host (listen_host)
3274 * and what we've sent to the remote server (channel_rfwd_bind_host)
3275 */
3276 static int
3277 open_listen_match_tcpip(ForwardPermission *allowed_open,
3278 const char *requestedhost, u_short requestedport, int translate)
3279 {
3280 const char *allowed_host;
3281
3282 if (allowed_open->host_to_connect == NULL)
3283 return 0;
3284 if (allowed_open->listen_port != requestedport)
3285 return 0;
3286 if (!translate && allowed_open->listen_host == NULL &&
3287 requestedhost == NULL)
3288 return 1;
3289 allowed_host = translate ?
3290 channel_rfwd_bind_host(allowed_open->listen_host) :
3291 allowed_open->listen_host;
3292 if (allowed_host == NULL ||
3293 strcmp(allowed_host, requestedhost) != 0)
3294 return 0;
3295 return 1;
3296 }
3297
3298 static int
3299 open_listen_match_streamlocal(ForwardPermission *allowed_open,
3300 const char *requestedpath)
3301 {
3302 if (allowed_open->host_to_connect == NULL)
3303 return 0;
3304 if (allowed_open->listen_port != PORT_STREAMLOCAL)
3305 return 0;
3306 if (allowed_open->listen_path == NULL ||
3307 strcmp(allowed_open->listen_path, requestedpath) != 0)
3308 return 0;
3309 return 1;
3310 }
3311
3312 /*
3313 * Request cancellation of remote forwarding of connection host:port from
3314 * local side.
3315 */
3316 static int
3317 channel_request_rforward_cancel_tcpip(const char *host, u_short port)
3318 {
3319 int i;
3320
3321 if (!compat20)
3322 return -1;
3323
3324 for (i = 0; i < num_permitted_opens; i++) {
3325 if (open_listen_match_tcpip(&permitted_opens[i], host, port, 0))
3326 break;
3327 }
3328 if (i >= num_permitted_opens) {
3329 debug("%s: requested forward not found", __func__);
3330 return -1;
3331 }
3332 packet_start(SSH2_MSG_GLOBAL_REQUEST);
3333 packet_put_cstring("cancel-tcpip-forward");
3334 packet_put_char(0);
3335 packet_put_cstring(channel_rfwd_bind_host(host));
3336 packet_put_int(port);
3337 packet_send();
3338
3339 permitted_opens[i].listen_port = 0;
3340 permitted_opens[i].port_to_connect = 0;
3341 free(permitted_opens[i].host_to_connect);
3342 permitted_opens[i].host_to_connect = NULL;
3343 free(permitted_opens[i].listen_host);
3344 permitted_opens[i].listen_host = NULL;
3345 permitted_opens[i].listen_path = NULL;
3346
3347 return 0;
3348 }
3349
3350 /*
3351 * Request cancellation of remote forwarding of Unix domain socket
3352 * path from local side.
3353 */
3354 static int
3355 channel_request_rforward_cancel_streamlocal(const char *path)
3356 {
3357 int i;
3358
3359 if (!compat20)
3360 return -1;
3361
3362 for (i = 0; i < num_permitted_opens; i++) {
3363 if (open_listen_match_streamlocal(&permitted_opens[i], path))
3364 break;
3365 }
3366 if (i >= num_permitted_opens) {
3367 debug("%s: requested forward not found", __func__);
3368 return -1;
3369 }
3370 packet_start(SSH2_MSG_GLOBAL_REQUEST);
3371 packet_put_cstring("cancel-streamlocal-forward@openssh.com");
3372 packet_put_char(0);
3373 packet_put_cstring(path);
3374 packet_send();
3375
3376 permitted_opens[i].listen_port = 0;
3377 permitted_opens[i].port_to_connect = 0;
3378 free(permitted_opens[i].host_to_connect);
3379 permitted_opens[i].host_to_connect = NULL;
3380 permitted_opens[i].listen_host = NULL;
3381 free(permitted_opens[i].listen_path);
3382 permitted_opens[i].listen_path = NULL;
3383
3384 return 0;
3385 }
3386
3387 /*
3388 * Request cancellation of remote forwarding of a connection from local side.
3389 */
3390 int
3391 channel_request_rforward_cancel(struct Forward *fwd)
3392 {
3393 if (fwd->listen_path != NULL) {
3394 return (channel_request_rforward_cancel_streamlocal(
3395 fwd->listen_path));
3396 } else {
3397 return (channel_request_rforward_cancel_tcpip(fwd->listen_host,
3398 fwd->listen_port ? fwd->listen_port : fwd->allocated_port));
3399 }
3400 }
3401
3402 /*
3403 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
3404 * listening for the port, and sends back a success reply (or disconnect
3405 * message if there was an error).
3406 */
3407 int
3408 channel_input_port_forward_request(int is_root, struct ForwardOptions *fwd_opts)
3409 {
3410 int success = 0;
3411 struct Forward fwd;
3412
3413 /* Get arguments from the packet. */
3414 memset(&fwd, 0, sizeof(fwd));
3415 fwd.listen_port = packet_get_int();
3416 fwd.connect_host = packet_get_string(NULL);
3417 fwd.connect_port = packet_get_int();
3418
3419 #ifndef HAVE_CYGWIN
3420 /*
3421 * Check that an unprivileged user is not trying to forward a
3422 * privileged port.
3423 */
3424 if (fwd.listen_port < IPPORT_RESERVED && !is_root)
3425 packet_disconnect(
3426 "Requested forwarding of port %d but user is not root.",
3427 fwd.listen_port);
3428 if (fwd.connect_port == 0)
3429 packet_disconnect("Dynamic forwarding denied.");
3430 #endif
3431
3432 /* Initiate forwarding */
3433 success = channel_setup_local_fwd_listener(&fwd, fwd_opts);
3434
3435 /* Free the argument string. */
3436 free(fwd.connect_host);
3437
3438 return (success ? 0 : -1);
3439 }
3440
3441 /*
3442 * Permits opening to any host/port if permitted_opens[] is empty. This is
3443 * usually called by the server, because the user could connect to any port
3444 * anyway, and the server has no way to know but to trust the client anyway.
3445 */
3446 void
3447 channel_permit_all_opens(void)
3448 {
3449 if (num_permitted_opens == 0)
3450 all_opens_permitted = 1;
3451 }
3452
3453 void
3454 channel_add_permitted_opens(char *host, int port)
3455 {
3456 debug("allow port forwarding to host %s port %d", host, port);
3457
3458 permitted_opens = xrealloc(permitted_opens,
3459 num_permitted_opens + 1, sizeof(*permitted_opens));
3460 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
3461 permitted_opens[num_permitted_opens].port_to_connect = port;
3462 permitted_opens[num_permitted_opens].listen_host = NULL;
3463 permitted_opens[num_permitted_opens].listen_path = NULL;
3464 permitted_opens[num_permitted_opens].listen_port = 0;
3465 num_permitted_opens++;
3466
3467 all_opens_permitted = 0;
3468 }
3469
3470 /*
3471 * Update the listen port for a dynamic remote forward, after
3472 * the actual 'newport' has been allocated. If 'newport' < 0 is
3473 * passed then they entry will be invalidated.
3474 */
3475 void
3476 channel_update_permitted_opens(int idx, int newport)
3477 {
3478 if (idx < 0 || idx >= num_permitted_opens) {
3479 debug("channel_update_permitted_opens: index out of range:"
3480 " %d num_permitted_opens %d", idx, num_permitted_opens);
3481 return;
3482 }
3483 debug("%s allowed port %d for forwarding to host %s port %d",
3484 newport > 0 ? "Updating" : "Removing",
3485 newport,
3486 permitted_opens[idx].host_to_connect,
3487 permitted_opens[idx].port_to_connect);
3488 if (newport >= 0) {
3489 permitted_opens[idx].listen_port =
3490 (datafellows & SSH_BUG_DYNAMIC_RPORT) ? 0 : newport;
3491 } else {
3492 permitted_opens[idx].listen_port = 0;
3493 permitted_opens[idx].port_to_connect = 0;
3494 free(permitted_opens[idx].host_to_connect);
3495 permitted_opens[idx].host_to_connect = NULL;
3496 free(permitted_opens[idx].listen_host);
3497 permitted_opens[idx].listen_host = NULL;
3498 free(permitted_opens[idx].listen_path);
3499 permitted_opens[idx].listen_path = NULL;
3500 }
3501 }
3502
3503 int
3504 channel_add_adm_permitted_opens(char *host, int port)
3505 {
3506 debug("config allows port forwarding to host %s port %d", host, port);
3507
3508 permitted_adm_opens = xrealloc(permitted_adm_opens,
3509 num_adm_permitted_opens + 1, sizeof(*permitted_adm_opens));
3510 permitted_adm_opens[num_adm_permitted_opens].host_to_connect
3511 = xstrdup(host);
3512 permitted_adm_opens[num_adm_permitted_opens].port_to_connect = port;
3513 permitted_adm_opens[num_adm_permitted_opens].listen_host = NULL;
3514 permitted_adm_opens[num_adm_permitted_opens].listen_path = NULL;
3515 permitted_adm_opens[num_adm_permitted_opens].listen_port = 0;
3516 return ++num_adm_permitted_opens;
3517 }
3518
3519 void
3520 channel_disable_adm_local_opens(void)
3521 {
3522 channel_clear_adm_permitted_opens();
3523 permitted_adm_opens = xmalloc(sizeof(*permitted_adm_opens));
3524 permitted_adm_opens[num_adm_permitted_opens].host_to_connect = NULL;
3525 num_adm_permitted_opens = 1;
3526 }
3527
3528 void
3529 channel_clear_permitted_opens(void)
3530 {
3531 int i;
3532
3533 for (i = 0; i < num_permitted_opens; i++) {
3534 free(permitted_opens[i].host_to_connect);
3535 free(permitted_opens[i].listen_host);
3536 free(permitted_opens[i].listen_path);
3537 }
3538 free(permitted_opens);
3539 permitted_opens = NULL;
3540 num_permitted_opens = 0;
3541 }
3542
3543 void
3544 channel_clear_adm_permitted_opens(void)
3545 {
3546 int i;
3547
3548 for (i = 0; i < num_adm_permitted_opens; i++) {
3549 free(permitted_adm_opens[i].host_to_connect);
3550 free(permitted_adm_opens[i].listen_host);
3551 free(permitted_adm_opens[i].listen_path);
3552 }
3553 free(permitted_adm_opens);
3554 permitted_adm_opens = NULL;
3555 num_adm_permitted_opens = 0;
3556 }
3557
3558 void
3559 channel_print_adm_permitted_opens(void)
3560 {
3561 int i;
3562
3563 printf("permitopen");
3564 if (num_adm_permitted_opens == 0) {
3565 printf(" any\n");
3566 return;
3567 }
3568 for (i = 0; i < num_adm_permitted_opens; i++)
3569 if (permitted_adm_opens[i].host_to_connect == NULL)
3570 printf(" none");
3571 else
3572 printf(" %s:%d", permitted_adm_opens[i].host_to_connect,
3573 permitted_adm_opens[i].port_to_connect);
3574 printf("\n");
3575 }
3576
3577 /* returns port number, FWD_PERMIT_ANY_PORT or -1 on error */
3578 int
3579 permitopen_port(const char *p)
3580 {
3581 int port;
3582
3583 if (strcmp(p, "*") == 0)
3584 return FWD_PERMIT_ANY_PORT;
3585 if ((port = a2port(p)) > 0)
3586 return port;
3587 return -1;
3588 }
3589
3590 /* Try to start non-blocking connect to next host in cctx list */
3591 static int
3592 connect_next(struct channel_connect *cctx)
3593 {
3594 int sock, saved_errno;
3595 struct sockaddr_un *sunaddr;
3596 char ntop[NI_MAXHOST], strport[MAX(NI_MAXSERV,sizeof(sunaddr->sun_path))];
3597
3598 for (; cctx->ai; cctx->ai = cctx->ai->ai_next) {
3599 switch (cctx->ai->ai_family) {
3600 case AF_UNIX:
3601 /* unix:pathname instead of host:port */
3602 sunaddr = (struct sockaddr_un *)cctx->ai->ai_addr;
3603 strlcpy(ntop, "unix", sizeof(ntop));
3604 strlcpy(strport, sunaddr->sun_path, sizeof(strport));
3605 break;
3606 case AF_INET:
3607 case AF_INET6:
3608 if (getnameinfo(cctx->ai->ai_addr, cctx->ai->ai_addrlen,
3609 ntop, sizeof(ntop), strport, sizeof(strport),
3610 NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
3611 error("connect_next: getnameinfo failed");
3612 continue;
3613 }
3614 break;
3615 default:
3616 continue;
3617 }
3618 if ((sock = socket(cctx->ai->ai_family, cctx->ai->ai_socktype,
3619 cctx->ai->ai_protocol)) == -1) {
3620 if (cctx->ai->ai_next == NULL)
3621 error("socket: %.100s", strerror(errno));
3622 else
3623 verbose("socket: %.100s", strerror(errno));
3624 continue;
3625 }
3626 if (set_nonblock(sock) == -1)
3627 fatal("%s: set_nonblock(%d)", __func__, sock);
3628 if (connect(sock, cctx->ai->ai_addr,
3629 cctx->ai->ai_addrlen) == -1 && errno != EINPROGRESS) {
3630 debug("connect_next: host %.100s ([%.100s]:%s): "
3631 "%.100s", cctx->host, ntop, strport,
3632 strerror(errno));
3633 saved_errno = errno;
3634 close(sock);
3635 errno = saved_errno;
3636 continue; /* fail -- try next */
3637 }
3638 if (cctx->ai->ai_family != AF_UNIX)
3639 set_nodelay(sock);
3640 debug("connect_next: host %.100s ([%.100s]:%s) "
3641 "in progress, fd=%d", cctx->host, ntop, strport, sock);
3642 cctx->ai = cctx->ai->ai_next;
3643 return sock;
3644 }
3645 return -1;
3646 }
3647
3648 static void
3649 channel_connect_ctx_free(struct channel_connect *cctx)
3650 {
3651 free(cctx->host);
3652 if (cctx->aitop) {
3653 if (cctx->aitop->ai_family == AF_UNIX)
3654 free(cctx->aitop);
3655 else
3656 freeaddrinfo(cctx->aitop);
3657 }
3658 memset(cctx, 0, sizeof(*cctx));
3659 }
3660
3661 /* Return CONNECTING channel to remote host:port or local socket path */
3662 static Channel *
3663 connect_to(const char *name, int port, char *ctype, char *rname)
3664 {
3665 struct addrinfo hints;
3666 int gaierr;
3667 int sock = -1;
3668 char strport[NI_MAXSERV];
3669 struct channel_connect cctx;
3670 Channel *c;
3671
3672 memset(&cctx, 0, sizeof(cctx));
3673
3674 if (port == PORT_STREAMLOCAL) {
3675 struct sockaddr_un *sunaddr;
3676 struct addrinfo *ai;
3677
3678 if (strlen(name) > sizeof(sunaddr->sun_path)) {
3679 error("%.100s: %.100s", name, strerror(ENAMETOOLONG));
3680 return (NULL);
3681 }
3682
3683 /*
3684 * Fake up a struct addrinfo for AF_UNIX connections.
3685 * channel_connect_ctx_free() must check ai_family
3686 * and use free() not freeaddirinfo() for AF_UNIX.
3687 */
3688 ai = xmalloc(sizeof(*ai) + sizeof(*sunaddr));
3689 memset(ai, 0, sizeof(*ai) + sizeof(*sunaddr));
3690 ai->ai_addr = (struct sockaddr *)(ai + 1);
3691 ai->ai_addrlen = sizeof(*sunaddr);
3692 ai->ai_family = AF_UNIX;
3693 ai->ai_socktype = SOCK_STREAM;
3694 ai->ai_protocol = PF_UNSPEC;
3695 sunaddr = (struct sockaddr_un *)ai->ai_addr;
3696 sunaddr->sun_family = AF_UNIX;
3697 strlcpy(sunaddr->sun_path, name, sizeof(sunaddr->sun_path));
3698 cctx.aitop = ai;
3699 } else {
3700 memset(&hints, 0, sizeof(hints));
3701 hints.ai_family = IPv4or6;
3702 hints.ai_socktype = SOCK_STREAM;
3703 snprintf(strport, sizeof strport, "%d", port);
3704 if ((gaierr = getaddrinfo(name, strport, &hints, &cctx.aitop)) != 0) {
3705 error("connect_to %.100s: unknown host (%s)", name,
3706 ssh_gai_strerror(gaierr));
3707 return NULL;
3708 }
3709 }
3710
3711 cctx.host = xstrdup(name);
3712 cctx.port = port;
3713 cctx.ai = cctx.aitop;
3714
3715 if ((sock = connect_next(&cctx)) == -1) {
3716 error("connect to %.100s port %d failed: %s",
3717 name, port, strerror(errno));
3718 channel_connect_ctx_free(&cctx);
3719 return NULL;
3720 }
3721 c = channel_new(ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1,
3722 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1);
3723 c->connect_ctx = cctx;
3724 return c;
3725 }
3726
3727 Channel *
3728 channel_connect_by_listen_address(const char *listen_host,
3729 u_short listen_port, char *ctype, char *rname)
3730 {
3731 int i;
3732
3733 for (i = 0; i < num_permitted_opens; i++) {
3734 if (open_listen_match_tcpip(&permitted_opens[i], listen_host,
3735 listen_port, 1)) {
3736 return connect_to(
3737 permitted_opens[i].host_to_connect,
3738 permitted_opens[i].port_to_connect, ctype, rname);
3739 }
3740 }
3741 error("WARNING: Server requests forwarding for unknown listen_port %d",
3742 listen_port);
3743 return NULL;
3744 }
3745
3746 Channel *
3747 channel_connect_by_listen_path(const char *path, char *ctype, char *rname)
3748 {
3749 int i;
3750
3751 for (i = 0; i < num_permitted_opens; i++) {
3752 if (open_listen_match_streamlocal(&permitted_opens[i], path)) {
3753 return connect_to(
3754 permitted_opens[i].host_to_connect,
3755 permitted_opens[i].port_to_connect, ctype, rname);
3756 }
3757 }
3758 error("WARNING: Server requests forwarding for unknown path %.100s",
3759 path);
3760 return NULL;
3761 }
3762
3763 /* Check if connecting to that port is permitted and connect. */
3764 Channel *
3765 channel_connect_to_port(const char *host, u_short port, char *ctype, char *rname)
3766 {
3767 int i, permit, permit_adm = 1;
3768
3769 permit = all_opens_permitted;
3770 if (!permit) {
3771 for (i = 0; i < num_permitted_opens; i++)
3772 if (open_match(&permitted_opens[i], host, port)) {
3773 permit = 1;
3774 break;
3775 }
3776 }
3777
3778 if (num_adm_permitted_opens > 0) {
3779 permit_adm = 0;
3780 for (i = 0; i < num_adm_permitted_opens; i++)
3781 if (open_match(&permitted_adm_opens[i], host, port)) {
3782 permit_adm = 1;
3783 break;
3784 }
3785 }
3786
3787 if (!permit || !permit_adm) {
3788 logit("Received request to connect to host %.100s port %d, "
3789 "but the request was denied.", host, port);
3790 return NULL;
3791 }
3792 return connect_to(host, port, ctype, rname);
3793 }
3794
3795 /* Check if connecting to that path is permitted and connect. */
3796 Channel *
3797 channel_connect_to_path(const char *path, char *ctype, char *rname)
3798 {
3799 int i, permit, permit_adm = 1;
3800
3801 permit = all_opens_permitted;
3802 if (!permit) {
3803 for (i = 0; i < num_permitted_opens; i++)
3804 if (open_match(&permitted_opens[i], path, PORT_STREAMLOCAL)) {
3805 permit = 1;
3806 break;
3807 }
3808 }
3809
3810 if (num_adm_permitted_opens > 0) {
3811 permit_adm = 0;
3812 for (i = 0; i < num_adm_permitted_opens; i++)
3813 if (open_match(&permitted_adm_opens[i], path, PORT_STREAMLOCAL)) {
3814 permit_adm = 1;
3815 break;
3816 }
3817 }
3818
3819 if (!permit || !permit_adm) {
3820 logit("Received request to connect to path %.100s, "
3821 "but the request was denied.", path);
3822 return NULL;
3823 }
3824 return connect_to(path, PORT_STREAMLOCAL, ctype, rname);
3825 }
3826
3827 void
3828 channel_send_window_changes(void)
3829 {
3830 u_int i;
3831 struct winsize ws;
3832
3833 for (i = 0; i < channels_alloc; i++) {
3834 if (channels[i] == NULL || !channels[i]->client_tty ||
3835 channels[i]->type != SSH_CHANNEL_OPEN)
3836 continue;
3837 if (ioctl(channels[i]->rfd, TIOCGWINSZ, &ws) < 0)
3838 continue;
3839 channel_request_start(i, "window-change", 0);
3840 packet_put_int((u_int)ws.ws_col);
3841 packet_put_int((u_int)ws.ws_row);
3842 packet_put_int((u_int)ws.ws_xpixel);
3843 packet_put_int((u_int)ws.ws_ypixel);
3844 packet_send();
3845 }
3846 }
3847
3848 /* -- X11 forwarding */
3849
3850 /*
3851 * Creates an internet domain socket for listening for X11 connections.
3852 * Returns 0 and a suitable display number for the DISPLAY variable
3853 * stored in display_numberp , or -1 if an error occurs.
3854 */
3855 int
3856 x11_create_display_inet(int x11_display_offset, int x11_use_localhost,
3857 int single_connection, u_int *display_numberp, int **chanids)
3858 {
3859 Channel *nc = NULL;
3860 int display_number, sock;
3861 u_short port;
3862 struct addrinfo hints, *ai, *aitop;
3863 char strport[NI_MAXSERV];
3864 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
3865
3866 if (chanids == NULL)
3867 return -1;
3868
3869 for (display_number = x11_display_offset;
3870 display_number < MAX_DISPLAYS;
3871 display_number++) {
3872 port = 6000 + display_number;
3873 memset(&hints, 0, sizeof(hints));
3874 hints.ai_family = IPv4or6;
3875 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE;
3876 hints.ai_socktype = SOCK_STREAM;
3877 snprintf(strport, sizeof strport, "%d", port);
3878 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
3879 error("getaddrinfo: %.100s", ssh_gai_strerror(gaierr));
3880 return -1;
3881 }
3882 for (ai = aitop; ai; ai = ai->ai_next) {
3883 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
3884 continue;
3885 sock = socket(ai->ai_family, ai->ai_socktype,
3886 ai->ai_protocol);
3887 if (sock < 0) {
3888 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)
3889 #ifdef EPFNOSUPPORT
3890 && (errno != EPFNOSUPPORT)
3891 #endif
3892 ) {
3893 error("socket: %.100s", strerror(errno));
3894 freeaddrinfo(aitop);
3895 return -1;
3896 } else {
3897 debug("x11_create_display_inet: Socket family %d not supported",
3898 ai->ai_family);
3899 continue;
3900 }
3901 }
3902 if (ai->ai_family == AF_INET6)
3903 sock_set_v6only(sock);
3904 if (x11_use_localhost)
3905 channel_set_reuseaddr(sock);
3906 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
3907 debug2("bind port %d: %.100s", port, strerror(errno));
3908 close(sock);
3909
3910 for (n = 0; n < num_socks; n++) {
3911 close(socks[n]);
3912 }
3913 num_socks = 0;
3914 break;
3915 }
3916 socks[num_socks++] = sock;
3917 if (num_socks == NUM_SOCKS)
3918 break;
3919 }
3920 freeaddrinfo(aitop);
3921 if (num_socks > 0)
3922 break;
3923 }
3924 if (display_number >= MAX_DISPLAYS) {
3925 error("Failed to allocate internet-domain X11 display socket.");
3926 return -1;
3927 }
3928 /* Start listening for connections on the socket. */
3929 for (n = 0; n < num_socks; n++) {
3930 sock = socks[n];
3931 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
3932 error("listen: %.100s", strerror(errno));
3933 close(sock);
3934 return -1;
3935 }
3936 }
3937
3938 /* Allocate a channel for each socket. */
3939 *chanids = xcalloc(num_socks + 1, sizeof(**chanids));
3940 for (n = 0; n < num_socks; n++) {
3941 sock = socks[n];
3942 nc = channel_new("x11 listener",
3943 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
3944 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
3945 0, "X11 inet listener", 1);
3946 nc->single_connection = single_connection;
3947 (*chanids)[n] = nc->self;
3948 }
3949 (*chanids)[n] = -1;
3950
3951 /* Return the display number for the DISPLAY environment variable. */
3952 *display_numberp = display_number;
3953 return (0);
3954 }
3955
3956 static int
3957 connect_local_xsocket_path(const char *pathname)
3958 {
3959 int sock;
3960 struct sockaddr_un addr;
3961
3962 sock = socket(AF_UNIX, SOCK_STREAM, 0);
3963 if (sock < 0)
3964 error("socket: %.100s", strerror(errno));
3965 memset(&addr, 0, sizeof(addr));
3966 addr.sun_family = AF_UNIX;
3967 strlcpy(addr.sun_path, pathname, sizeof addr.sun_path);
3968 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0)
3969 return sock;
3970 close(sock);
3971 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
3972 return -1;
3973 }
3974
3975 static int
3976 connect_local_xsocket(u_int dnr)
3977 {
3978 char buf[1024];
3979 snprintf(buf, sizeof buf, _PATH_UNIX_X, dnr);
3980 return connect_local_xsocket_path(buf);
3981 }
3982
3983 int
3984 x11_connect_display(void)
3985 {
3986 u_int display_number;
3987 const char *display;
3988 char buf[1024], *cp;
3989 struct addrinfo hints, *ai, *aitop;
3990 char strport[NI_MAXSERV];
3991 int gaierr, sock = 0;
3992
3993 /* Try to open a socket for the local X server. */
3994 display = getenv("DISPLAY");
3995 if (!display) {
3996 error("DISPLAY not set.");
3997 return -1;
3998 }
3999 /*
4000 * Now we decode the value of the DISPLAY variable and make a
4001 * connection to the real X server.
4002 */
4003
4004 /* Check if the display is from launchd. */
4005 #ifdef __APPLE__
4006 if (strncmp(display, "/tmp/launch", 11) == 0) {
4007 sock = connect_local_xsocket_path(display);
4008 if (sock < 0)
4009 return -1;
4010
4011 /* OK, we now have a connection to the display. */
4012 return sock;
4013 }
4014 #endif
4015 /*
4016 * Check if it is a unix domain socket. Unix domain displays are in
4017 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
4018 */
4019 if (strncmp(display, "unix:", 5) == 0 ||
4020 display[0] == ':') {
4021 /* Connect to the unix domain socket. */
4022 if (sscanf(strrchr(display, ':') + 1, "%u", &display_number) != 1) {
4023 error("Could not parse display number from DISPLAY: %.100s",
4024 display);
4025 return -1;
4026 }
4027 /* Create a socket. */
4028 sock = connect_local_xsocket(display_number);
4029 if (sock < 0)
4030 return -1;
4031
4032 /* OK, we now have a connection to the display. */
4033 return sock;
4034 }
4035 /*
4036 * Connect to an inet socket. The DISPLAY value is supposedly
4037 * hostname:d[.s], where hostname may also be numeric IP address.
4038 */
4039 strlcpy(buf, display, sizeof(buf));
4040 cp = strchr(buf, ':');
4041 if (!cp) {
4042 error("Could not find ':' in DISPLAY: %.100s", display);
4043 return -1;
4044 }
4045 *cp = 0;
4046 /* buf now contains the host name. But first we parse the display number. */
4047 if (sscanf(cp + 1, "%u", &display_number) != 1) {
4048 error("Could not parse display number from DISPLAY: %.100s",
4049 display);
4050 return -1;
4051 }
4052
4053 /* Look up the host address */
4054 memset(&hints, 0, sizeof(hints));
4055 hints.ai_family = IPv4or6;
4056 hints.ai_socktype = SOCK_STREAM;
4057 snprintf(strport, sizeof strport, "%u", 6000 + display_number);
4058 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
4059 error("%.100s: unknown host. (%s)", buf,
4060 ssh_gai_strerror(gaierr));
4061 return -1;
4062 }
4063 for (ai = aitop; ai; ai = ai->ai_next) {
4064 /* Create a socket. */
4065 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
4066 if (sock < 0) {
4067 debug2("socket: %.100s", strerror(errno));
4068 continue;
4069 }
4070 /* Connect it to the display. */
4071 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
4072 debug2("connect %.100s port %u: %.100s", buf,
4073 6000 + display_number, strerror(errno));
4074 close(sock);
4075 continue;
4076 }
4077 /* Success */
4078 break;
4079 }
4080 freeaddrinfo(aitop);
4081 if (!ai) {
4082 error("connect %.100s port %u: %.100s", buf, 6000 + display_number,
4083 strerror(errno));
4084 return -1;
4085 }
4086 set_nodelay(sock);
4087 return sock;
4088 }
4089
4090 /*
4091 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
4092 * the remote channel number. We should do whatever we want, and respond
4093 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
4094 */
4095
4096 /* ARGSUSED */
4097 void
4098 x11_input_open(int type, u_int32_t seq, void *ctxt)
4099 {
4100 Channel *c = NULL;
4101 int remote_id, sock = 0;
4102 char *remote_host;
4103
4104 debug("Received X11 open request.");
4105
4106 remote_id = packet_get_int();
4107
4108 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
4109 remote_host = packet_get_string(NULL);
4110 } else {
4111 remote_host = xstrdup("unknown (remote did not supply name)");
4112 }
4113 packet_check_eom();
4114
4115 /* Obtain a connection to the real X display. */
4116 sock = x11_connect_display();
4117 if (sock != -1) {
4118 /* Allocate a channel for this connection. */
4119 c = channel_new("connected x11 socket",
4120 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
4121 remote_host, 1);
4122 c->remote_id = remote_id;
4123 c->force_drain = 1;
4124 }
4125 free(remote_host);
4126 if (c == NULL) {
4127 /* Send refusal to the remote host. */
4128 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
4129 packet_put_int(remote_id);
4130 } else {
4131 /* Send a confirmation to the remote host. */
4132 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
4133 packet_put_int(remote_id);
4134 packet_put_int(c->self);
4135 }
4136 packet_send();
4137 }
4138
4139 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
4140 /* ARGSUSED */
4141 void
4142 deny_input_open(int type, u_int32_t seq, void *ctxt)
4143 {
4144 int rchan = packet_get_int();
4145
4146 switch (type) {
4147 case SSH_SMSG_AGENT_OPEN:
4148 error("Warning: ssh server tried agent forwarding.");
4149 break;
4150 case SSH_SMSG_X11_OPEN:
4151 error("Warning: ssh server tried X11 forwarding.");
4152 break;
4153 default:
4154 error("deny_input_open: type %d", type);
4155 break;
4156 }
4157 error("Warning: this is probably a break-in attempt by a malicious server.");
4158 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
4159 packet_put_int(rchan);
4160 packet_send();
4161 }
4162
4163 /*
4164 * Requests forwarding of X11 connections, generates fake authentication
4165 * data, and enables authentication spoofing.
4166 * This should be called in the client only.
4167 */
4168 void
4169 x11_request_forwarding_with_spoofing(int client_session_id, const char *disp,
4170 const char *proto, const char *data, int want_reply)
4171 {
4172 u_int data_len = (u_int) strlen(data) / 2;
4173 u_int i, value;
4174 char *new_data;
4175 int screen_number;
4176 const char *cp;
4177 u_int32_t rnd = 0;
4178
4179 if (x11_saved_display == NULL)
4180 x11_saved_display = xstrdup(disp);
4181 else if (strcmp(disp, x11_saved_display) != 0) {
4182 error("x11_request_forwarding_with_spoofing: different "
4183 "$DISPLAY already forwarded");
4184 return;
4185 }
4186
4187 cp = strchr(disp, ':');
4188 if (cp)
4189 cp = strchr(cp, '.');
4190 if (cp)
4191 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL);
4192 else
4193 screen_number = 0;
4194
4195 if (x11_saved_proto == NULL) {
4196 /* Save protocol name. */
4197 x11_saved_proto = xstrdup(proto);
4198 /*
4199 * Extract real authentication data and generate fake data
4200 * of the same length.
4201 */
4202 x11_saved_data = xmalloc(data_len);
4203 x11_fake_data = xmalloc(data_len);
4204 for (i = 0; i < data_len; i++) {
4205 if (sscanf(data + 2 * i, "%2x", &value) != 1)
4206 fatal("x11_request_forwarding: bad "
4207 "authentication data: %.100s", data);
4208 if (i % 4 == 0)
4209 rnd = arc4random();
4210 x11_saved_data[i] = value;
4211 x11_fake_data[i] = rnd & 0xff;
4212 rnd >>= 8;
4213 }
4214 x11_saved_data_len = data_len;
4215 x11_fake_data_len = data_len;
4216 }
4217
4218 /* Convert the fake data into hex. */
4219 new_data = tohex(x11_fake_data, data_len);
4220
4221 /* Send the request packet. */
4222 if (compat20) {
4223 channel_request_start(client_session_id, "x11-req", want_reply);
4224 packet_put_char(0); /* XXX bool single connection */
4225 } else {
4226 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
4227 }
4228 packet_put_cstring(proto);
4229 packet_put_cstring(new_data);
4230 packet_put_int(screen_number);
4231 packet_send();
4232 packet_write_wait();
4233 free(new_data);
4234 }
4235
4236
4237 /* -- agent forwarding */
4238
4239 /* Sends a message to the server to request authentication fd forwarding. */
4240
4241 void
4242 auth_request_forwarding(void)
4243 {
4244 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
4245 packet_send();
4246 packet_write_wait();
4247 }
DragonFly BSD