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drm: Add atomic_cmpxchg()
[dragonfly.git] / crypto / openssh / channels.c
blob4521837191ab34aa3335f478d28083605f620203
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
183 static int hpn_disabled = 0;
184 static int hpn_buffer_size = 2 * 1024 * 1024;
185
186 /* -- channel core */
187
188
189
190 Channel *
191 channel_by_id(int id)
192 {
193 Channel *c;
194
195 if (id < 0 || (u_int)id >= channels_alloc) {
196 logit("channel_by_id: %d: bad id", id);
197 return NULL;
198 }
199 c = channels[id];
200 if (c == NULL) {
201 logit("channel_by_id: %d: bad id: channel free", id);
202 return NULL;
203 }
204 return c;
205 }
206
207 /*
208 * Returns the channel if it is allowed to receive protocol messages.
209 * Private channels, like listening sockets, may not receive messages.
210 */
211 Channel *
212 channel_lookup(int id)
213 {
214 Channel *c;
215
216 if ((c = channel_by_id(id)) == NULL)
217 return (NULL);
218
219 switch (c->type) {
220 case SSH_CHANNEL_X11_OPEN:
221 case SSH_CHANNEL_LARVAL:
222 case SSH_CHANNEL_CONNECTING:
223 case SSH_CHANNEL_DYNAMIC:
224 case SSH_CHANNEL_OPENING:
225 case SSH_CHANNEL_OPEN:
226 case SSH_CHANNEL_INPUT_DRAINING:
227 case SSH_CHANNEL_OUTPUT_DRAINING:
228 case SSH_CHANNEL_ABANDONED:
229 return (c);
230 }
231 logit("Non-public channel %d, type %d.", id, c->type);
232 return (NULL);
233 }
234
235 /*
236 * Register filedescriptors for a channel, used when allocating a channel or
237 * when the channel consumer/producer is ready, e.g. shell exec'd
238 */
239 static void
240 channel_register_fds(Channel *c, int rfd, int wfd, int efd,
241 int extusage, int nonblock, int is_tty)
242 {
243 /* Update the maximum file descriptor value. */
244 channel_max_fd = MAX(channel_max_fd, rfd);
245 channel_max_fd = MAX(channel_max_fd, wfd);
246 channel_max_fd = MAX(channel_max_fd, efd);
247
248 if (rfd != -1)
249 fcntl(rfd, F_SETFD, FD_CLOEXEC);
250 if (wfd != -1 && wfd != rfd)
251 fcntl(wfd, F_SETFD, FD_CLOEXEC);
252 if (efd != -1 && efd != rfd && efd != wfd)
253 fcntl(efd, F_SETFD, FD_CLOEXEC);
254
255 c->rfd = rfd;
256 c->wfd = wfd;
257 c->sock = (rfd == wfd) ? rfd : -1;
258 c->efd = efd;
259 c->extended_usage = extusage;
260
261 if ((c->isatty = is_tty) != 0)
262 debug2("channel %d: rfd %d isatty", c->self, c->rfd);
263 #ifdef _AIX
264 /* XXX: Later AIX versions can't push as much data to tty */
265 c->wfd_isatty = is_tty || isatty(c->wfd);
266 #endif
267
268 /* enable nonblocking mode */
269 if (nonblock) {
270 if (rfd != -1)
271 set_nonblock(rfd);
272 if (wfd != -1)
273 set_nonblock(wfd);
274 if (efd != -1)
275 set_nonblock(efd);
276 }
277 }
278
279 /*
280 * Allocate a new channel object and set its type and socket. This will cause
281 * remote_name to be freed.
282 */
283 Channel *
284 channel_new(char *ctype, int type, int rfd, int wfd, int efd,
285 u_int window, u_int maxpack, int extusage, char *remote_name, int nonblock)
286 {
287 int found;
288 u_int i;
289 Channel *c;
290
291 /* Do initial allocation if this is the first call. */
292 if (channels_alloc == 0) {
293 channels_alloc = 10;
294 channels = xcalloc(channels_alloc, sizeof(Channel *));
295 for (i = 0; i < channels_alloc; i++)
296 channels[i] = NULL;
297 }
298 /* Try to find a free slot where to put the new channel. */
299 for (found = -1, i = 0; i < channels_alloc; i++)
300 if (channels[i] == NULL) {
301 /* Found a free slot. */
302 found = (int)i;
303 break;
304 }
305 if (found < 0) {
306 /* There are no free slots. Take last+1 slot and expand the array. */
307 found = channels_alloc;
308 if (channels_alloc > 10000)
309 fatal("channel_new: internal error: channels_alloc %d "
310 "too big.", channels_alloc);
311 channels = xrealloc(channels, channels_alloc + 10,
312 sizeof(Channel *));
313 channels_alloc += 10;
314 debug2("channel: expanding %d", channels_alloc);
315 for (i = found; i < channels_alloc; i++)
316 channels[i] = NULL;
317 }
318 /* Initialize and return new channel. */
319 c = channels[found] = xcalloc(1, sizeof(Channel));
320 buffer_init(&c->input);
321 buffer_init(&c->output);
322 buffer_init(&c->extended);
323 c->path = NULL;
324 c->listening_addr = NULL;
325 c->listening_port = 0;
326 c->ostate = CHAN_OUTPUT_OPEN;
327 c->istate = CHAN_INPUT_OPEN;
328 c->flags = 0;
329 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock, 0);
330 c->notbefore = 0;
331 c->self = found;
332 c->type = type;
333 c->ctype = ctype;
334 c->local_window = window;
335 c->local_window_max = window;
336 c->local_consumed = 0;
337 c->local_maxpacket = maxpack;
338 c->dynamic_window = 0;
339 c->remote_id = -1;
340 c->remote_name = xstrdup(remote_name);
341 c->remote_window = 0;
342 c->remote_maxpacket = 0;
343 c->force_drain = 0;
344 c->single_connection = 0;
345 c->detach_user = NULL;
346 c->detach_close = 0;
347 c->open_confirm = NULL;
348 c->open_confirm_ctx = NULL;
349 c->input_filter = NULL;
350 c->output_filter = NULL;
351 c->filter_ctx = NULL;
352 c->filter_cleanup = NULL;
353 c->ctl_chan = -1;
354 c->mux_rcb = NULL;
355 c->mux_ctx = NULL;
356 c->mux_pause = 0;
357 c->delayed = 1; /* prevent call to channel_post handler */
358 TAILQ_INIT(&c->status_confirms);
359 debug("channel %d: new [%s]", found, remote_name);
360 return c;
361 }
362
363 static int
364 channel_find_maxfd(void)
365 {
366 u_int i;
367 int max = 0;
368 Channel *c;
369
370 for (i = 0; i < channels_alloc; i++) {
371 c = channels[i];
372 if (c != NULL) {
373 max = MAX(max, c->rfd);
374 max = MAX(max, c->wfd);
375 max = MAX(max, c->efd);
376 }
377 }
378 return max;
379 }
380
381 int
382 channel_close_fd(int *fdp)
383 {
384 int ret = 0, fd = *fdp;
385
386 if (fd != -1) {
387 ret = close(fd);
388 *fdp = -1;
389 if (fd == channel_max_fd)
390 channel_max_fd = channel_find_maxfd();
391 }
392 return ret;
393 }
394
395 /* Close all channel fd/socket. */
396 static void
397 channel_close_fds(Channel *c)
398 {
399 channel_close_fd(&c->sock);
400 channel_close_fd(&c->rfd);
401 channel_close_fd(&c->wfd);
402 channel_close_fd(&c->efd);
403 }
404
405 /* Free the channel and close its fd/socket. */
406 void
407 channel_free(Channel *c)
408 {
409 char *s;
410 u_int i, n;
411 struct channel_confirm *cc;
412
413 for (n = 0, i = 0; i < channels_alloc; i++)
414 if (channels[i])
415 n++;
416 debug("channel %d: free: %s, nchannels %u", c->self,
417 c->remote_name ? c->remote_name : "???", n);
418
419 s = channel_open_message();
420 debug3("channel %d: status: %s", c->self, s);
421 free(s);
422
423 if (c->sock != -1)
424 shutdown(c->sock, SHUT_RDWR);
425 channel_close_fds(c);
426 buffer_free(&c->input);
427 buffer_free(&c->output);
428 buffer_free(&c->extended);
429 free(c->remote_name);
430 c->remote_name = NULL;
431 free(c->path);
432 c->path = NULL;
433 free(c->listening_addr);
434 c->listening_addr = NULL;
435 while ((cc = TAILQ_FIRST(&c->status_confirms)) != NULL) {
436 if (cc->abandon_cb != NULL)
437 cc->abandon_cb(c, cc->ctx);
438 TAILQ_REMOVE(&c->status_confirms, cc, entry);
439 explicit_bzero(cc, sizeof(*cc));
440 free(cc);
441 }
442 if (c->filter_cleanup != NULL && c->filter_ctx != NULL)
443 c->filter_cleanup(c->self, c->filter_ctx);
444 channels[c->self] = NULL;
445 free(c);
446 }
447
448 void
449 channel_free_all(void)
450 {
451 u_int i;
452
453 for (i = 0; i < channels_alloc; i++)
454 if (channels[i] != NULL)
455 channel_free(channels[i]);
456 }
457
458 /*
459 * Closes the sockets/fds of all channels. This is used to close extra file
460 * descriptors after a fork.
461 */
462 void
463 channel_close_all(void)
464 {
465 u_int i;
466
467 for (i = 0; i < channels_alloc; i++)
468 if (channels[i] != NULL)
469 channel_close_fds(channels[i]);
470 }
471
472 /*
473 * Stop listening to channels.
474 */
475 void
476 channel_stop_listening(void)
477 {
478 u_int i;
479 Channel *c;
480
481 for (i = 0; i < channels_alloc; i++) {
482 c = channels[i];
483 if (c != NULL) {
484 switch (c->type) {
485 case SSH_CHANNEL_AUTH_SOCKET:
486 case SSH_CHANNEL_PORT_LISTENER:
487 case SSH_CHANNEL_RPORT_LISTENER:
488 case SSH_CHANNEL_X11_LISTENER:
489 case SSH_CHANNEL_UNIX_LISTENER:
490 case SSH_CHANNEL_RUNIX_LISTENER:
491 channel_close_fd(&c->sock);
492 channel_free(c);
493 break;
494 }
495 }
496 }
497 }
498
499 /*
500 * Returns true if no channel has too much buffered data, and false if one or
501 * more channel is overfull.
502 */
503 int
504 channel_not_very_much_buffered_data(void)
505 {
506 u_int i;
507 Channel *c;
508
509 for (i = 0; i < channels_alloc; i++) {
510 c = channels[i];
511 if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
512 #if 0
513 if (!compat20 &&
514 buffer_len(&c->input) > packet_get_maxsize()) {
515 debug2("channel %d: big input buffer %d",
516 c->self, buffer_len(&c->input));
517 return 0;
518 }
519 #endif
520 if (buffer_len(&c->output) > packet_get_maxsize()) {
521 debug2("channel %d: big output buffer %u > %u",
522 c->self, buffer_len(&c->output),
523 packet_get_maxsize());
524 return 0;
525 }
526 }
527 }
528 return 1;
529 }
530
531 /* Returns true if any channel is still open. */
532 int
533 channel_still_open(void)
534 {
535 u_int i;
536 Channel *c;
537
538 for (i = 0; i < channels_alloc; i++) {
539 c = channels[i];
540 if (c == NULL)
541 continue;
542 switch (c->type) {
543 case SSH_CHANNEL_X11_LISTENER:
544 case SSH_CHANNEL_PORT_LISTENER:
545 case SSH_CHANNEL_RPORT_LISTENER:
546 case SSH_CHANNEL_MUX_LISTENER:
547 case SSH_CHANNEL_CLOSED:
548 case SSH_CHANNEL_AUTH_SOCKET:
549 case SSH_CHANNEL_DYNAMIC:
550 case SSH_CHANNEL_CONNECTING:
551 case SSH_CHANNEL_ZOMBIE:
552 case SSH_CHANNEL_ABANDONED:
553 case SSH_CHANNEL_UNIX_LISTENER:
554 case SSH_CHANNEL_RUNIX_LISTENER:
555 continue;
556 case SSH_CHANNEL_LARVAL:
557 if (!compat20)
558 fatal("cannot happen: SSH_CHANNEL_LARVAL");
559 continue;
560 case SSH_CHANNEL_OPENING:
561 case SSH_CHANNEL_OPEN:
562 case SSH_CHANNEL_X11_OPEN:
563 case SSH_CHANNEL_MUX_CLIENT:
564 return 1;
565 case SSH_CHANNEL_INPUT_DRAINING:
566 case SSH_CHANNEL_OUTPUT_DRAINING:
567 if (!compat13)
568 fatal("cannot happen: OUT_DRAIN");
569 return 1;
570 default:
571 fatal("channel_still_open: bad channel type %d", c->type);
572 /* NOTREACHED */
573 }
574 }
575 return 0;
576 }
577
578 /* Returns the id of an open channel suitable for keepaliving */
579 int
580 channel_find_open(void)
581 {
582 u_int i;
583 Channel *c;
584
585 for (i = 0; i < channels_alloc; i++) {
586 c = channels[i];
587 if (c == NULL || c->remote_id < 0)
588 continue;
589 switch (c->type) {
590 case SSH_CHANNEL_CLOSED:
591 case SSH_CHANNEL_DYNAMIC:
592 case SSH_CHANNEL_X11_LISTENER:
593 case SSH_CHANNEL_PORT_LISTENER:
594 case SSH_CHANNEL_RPORT_LISTENER:
595 case SSH_CHANNEL_MUX_LISTENER:
596 case SSH_CHANNEL_MUX_CLIENT:
597 case SSH_CHANNEL_OPENING:
598 case SSH_CHANNEL_CONNECTING:
599 case SSH_CHANNEL_ZOMBIE:
600 case SSH_CHANNEL_ABANDONED:
601 case SSH_CHANNEL_UNIX_LISTENER:
602 case SSH_CHANNEL_RUNIX_LISTENER:
603 continue;
604 case SSH_CHANNEL_LARVAL:
605 case SSH_CHANNEL_AUTH_SOCKET:
606 case SSH_CHANNEL_OPEN:
607 case SSH_CHANNEL_X11_OPEN:
608 return i;
609 case SSH_CHANNEL_INPUT_DRAINING:
610 case SSH_CHANNEL_OUTPUT_DRAINING:
611 if (!compat13)
612 fatal("cannot happen: OUT_DRAIN");
613 return i;
614 default:
615 fatal("channel_find_open: bad channel type %d", c->type);
616 /* NOTREACHED */
617 }
618 }
619 return -1;
620 }
621
622
623 /*
624 * Returns a message describing the currently open forwarded connections,
625 * suitable for sending to the client. The message contains crlf pairs for
626 * newlines.
627 */
628 char *
629 channel_open_message(void)
630 {
631 Buffer buffer;
632 Channel *c;
633 char buf[1024], *cp;
634 u_int i;
635
636 buffer_init(&buffer);
637 snprintf(buf, sizeof buf, "The following connections are open:\r\n");
638 buffer_append(&buffer, buf, strlen(buf));
639 for (i = 0; i < channels_alloc; i++) {
640 c = channels[i];
641 if (c == NULL)
642 continue;
643 switch (c->type) {
644 case SSH_CHANNEL_X11_LISTENER:
645 case SSH_CHANNEL_PORT_LISTENER:
646 case SSH_CHANNEL_RPORT_LISTENER:
647 case SSH_CHANNEL_CLOSED:
648 case SSH_CHANNEL_AUTH_SOCKET:
649 case SSH_CHANNEL_ZOMBIE:
650 case SSH_CHANNEL_ABANDONED:
651 case SSH_CHANNEL_MUX_CLIENT:
652 case SSH_CHANNEL_MUX_LISTENER:
653 case SSH_CHANNEL_UNIX_LISTENER:
654 case SSH_CHANNEL_RUNIX_LISTENER:
655 continue;
656 case SSH_CHANNEL_LARVAL:
657 case SSH_CHANNEL_OPENING:
658 case SSH_CHANNEL_CONNECTING:
659 case SSH_CHANNEL_DYNAMIC:
660 case SSH_CHANNEL_OPEN:
661 case SSH_CHANNEL_X11_OPEN:
662 case SSH_CHANNEL_INPUT_DRAINING:
663 case SSH_CHANNEL_OUTPUT_DRAINING:
664 snprintf(buf, sizeof buf,
665 " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d cc %d)\r\n",
666 c->self, c->remote_name,
667 c->type, c->remote_id,
668 c->istate, buffer_len(&c->input),
669 c->ostate, buffer_len(&c->output),
670 c->rfd, c->wfd, c->ctl_chan);
671 buffer_append(&buffer, buf, strlen(buf));
672 continue;
673 default:
674 fatal("channel_open_message: bad channel type %d", c->type);
675 /* NOTREACHED */
676 }
677 }
678 buffer_append(&buffer, "\0", 1);
679 cp = xstrdup(buffer_ptr(&buffer));
680 buffer_free(&buffer);
681 return cp;
682 }
683
684 void
685 channel_send_open(int id)
686 {
687 Channel *c = channel_lookup(id);
688
689 if (c == NULL) {
690 logit("channel_send_open: %d: bad id", id);
691 return;
692 }
693 debug2("channel %d: send open", id);
694 packet_start(SSH2_MSG_CHANNEL_OPEN);
695 packet_put_cstring(c->ctype);
696 packet_put_int(c->self);
697 packet_put_int(c->local_window);
698 packet_put_int(c->local_maxpacket);
699 packet_send();
700 }
701
702 void
703 channel_request_start(int id, char *service, int wantconfirm)
704 {
705 Channel *c = channel_lookup(id);
706
707 if (c == NULL) {
708 logit("channel_request_start: %d: unknown channel id", id);
709 return;
710 }
711 debug2("channel %d: request %s confirm %d", id, service, wantconfirm);
712 packet_start(SSH2_MSG_CHANNEL_REQUEST);
713 packet_put_int(c->remote_id);
714 packet_put_cstring(service);
715 packet_put_char(wantconfirm);
716 }
717
718 void
719 channel_register_status_confirm(int id, channel_confirm_cb *cb,
720 channel_confirm_abandon_cb *abandon_cb, void *ctx)
721 {
722 struct channel_confirm *cc;
723 Channel *c;
724
725 if ((c = channel_lookup(id)) == NULL)
726 fatal("channel_register_expect: %d: bad id", id);
727
728 cc = xcalloc(1, sizeof(*cc));
729 cc->cb = cb;
730 cc->abandon_cb = abandon_cb;
731 cc->ctx = ctx;
732 TAILQ_INSERT_TAIL(&c->status_confirms, cc, entry);
733 }
734
735 void
736 channel_register_open_confirm(int id, channel_open_fn *fn, void *ctx)
737 {
738 Channel *c = channel_lookup(id);
739
740 if (c == NULL) {
741 logit("channel_register_open_confirm: %d: bad id", id);
742 return;
743 }
744 c->open_confirm = fn;
745 c->open_confirm_ctx = ctx;
746 }
747
748 void
749 channel_register_cleanup(int id, channel_callback_fn *fn, int do_close)
750 {
751 Channel *c = channel_by_id(id);
752
753 if (c == NULL) {
754 logit("channel_register_cleanup: %d: bad id", id);
755 return;
756 }
757 c->detach_user = fn;
758 c->detach_close = do_close;
759 }
760
761 void
762 channel_cancel_cleanup(int id)
763 {
764 Channel *c = channel_by_id(id);
765
766 if (c == NULL) {
767 logit("channel_cancel_cleanup: %d: bad id", id);
768 return;
769 }
770 c->detach_user = NULL;
771 c->detach_close = 0;
772 }
773
774 void
775 channel_register_filter(int id, channel_infilter_fn *ifn,
776 channel_outfilter_fn *ofn, channel_filter_cleanup_fn *cfn, void *ctx)
777 {
778 Channel *c = channel_lookup(id);
779
780 if (c == NULL) {
781 logit("channel_register_filter: %d: bad id", id);
782 return;
783 }
784 c->input_filter = ifn;
785 c->output_filter = ofn;
786 c->filter_ctx = ctx;
787 c->filter_cleanup = cfn;
788 }
789
790 void
791 channel_set_fds(int id, int rfd, int wfd, int efd,
792 int extusage, int nonblock, int is_tty, u_int window_max)
793 {
794 Channel *c = channel_lookup(id);
795
796 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
797 fatal("channel_activate for non-larval channel %d.", id);
798 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock, is_tty);
799 c->type = SSH_CHANNEL_OPEN;
800 c->local_window = c->local_window_max = window_max;
801 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
802 packet_put_int(c->remote_id);
803 packet_put_int(c->local_window);
804 packet_send();
805 }
806
807 /*
808 * 'channel_pre*' are called just before select() to add any bits relevant to
809 * channels in the select bitmasks.
810 */
811 /*
812 * 'channel_post*': perform any appropriate operations for channels which
813 * have events pending.
814 */
815 typedef void chan_fn(Channel *c, fd_set *readset, fd_set *writeset);
816 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
817 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
818
819 /* ARGSUSED */
820 static void
821 channel_pre_listener(Channel *c, fd_set *readset, fd_set *writeset)
822 {
823 FD_SET(c->sock, readset);
824 }
825
826 /* ARGSUSED */
827 static void
828 channel_pre_connecting(Channel *c, fd_set *readset, fd_set *writeset)
829 {
830 debug3("channel %d: waiting for connection", c->self);
831 FD_SET(c->sock, writeset);
832 }
833
834 static void
835 channel_pre_open_13(Channel *c, fd_set *readset, fd_set *writeset)
836 {
837 if (buffer_len(&c->input) < packet_get_maxsize())
838 FD_SET(c->sock, readset);
839 if (buffer_len(&c->output) > 0)
840 FD_SET(c->sock, writeset);
841 }
842
843 int channel_tcpwinsz () {
844 u_int32_t tcpwinsz = 0;
845 socklen_t optsz = sizeof(tcpwinsz);
846 int ret = -1;
847
848 /* if we aren't on a socket return 128KB*/
849 if(!packet_connection_is_on_socket())
850 return(128*1024);
851 ret = getsockopt(packet_get_connection_in(),
852 SOL_SOCKET, SO_RCVBUF, &tcpwinsz, &optsz);
853 /* return no more than 64MB */
854 if ((ret == 0) && tcpwinsz > SSHBUF_SIZE_MAX)
855 tcpwinsz = SSHBUF_SIZE_MAX;
856 debug2("tcpwinsz: %d for connection: %d", tcpwinsz,
857 packet_get_connection_in());
858 return(tcpwinsz);
859 }
860
861 static void
862 channel_pre_open(Channel *c, fd_set *readset, fd_set *writeset)
863 {
864 u_int limit = compat20 ? c->remote_window : packet_get_maxsize();
865
866 /* check buffer limits */
867 if ((!c->tcpwinsz) || (c->dynamic_window > 0))
868 c->tcpwinsz = channel_tcpwinsz();
869
870 limit = MIN(limit, 2 * c->tcpwinsz);
871
872 if (c->istate == CHAN_INPUT_OPEN &&
873 limit > 0 &&
874 buffer_len(&c->input) < limit &&
875 buffer_check_alloc(&c->input, CHAN_RBUF))
876 FD_SET(c->rfd, readset);
877 if (c->ostate == CHAN_OUTPUT_OPEN ||
878 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
879 if (buffer_len(&c->output) > 0) {
880 FD_SET(c->wfd, writeset);
881 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
882 if (CHANNEL_EFD_OUTPUT_ACTIVE(c))
883 debug2("channel %d: obuf_empty delayed efd %d/(%d)",
884 c->self, c->efd, buffer_len(&c->extended));
885 else
886 chan_obuf_empty(c);
887 }
888 }
889 /** XXX check close conditions, too */
890 if (compat20 && c->efd != -1 &&
891 !(c->istate == CHAN_INPUT_CLOSED && c->ostate == CHAN_OUTPUT_CLOSED)) {
892 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
893 buffer_len(&c->extended) > 0)
894 FD_SET(c->efd, writeset);
895 else if (c->efd != -1 && !(c->flags & CHAN_EOF_SENT) &&
896 (c->extended_usage == CHAN_EXTENDED_READ ||
897 c->extended_usage == CHAN_EXTENDED_IGNORE) &&
898 buffer_len(&c->extended) < c->remote_window)
899 FD_SET(c->efd, readset);
900 }
901 /* XXX: What about efd? races? */
902 }
903
904 /* ARGSUSED */
905 static void
906 channel_pre_input_draining(Channel *c, fd_set *readset, fd_set *writeset)
907 {
908 if (buffer_len(&c->input) == 0) {
909 packet_start(SSH_MSG_CHANNEL_CLOSE);
910 packet_put_int(c->remote_id);
911 packet_send();
912 c->type = SSH_CHANNEL_CLOSED;
913 debug2("channel %d: closing after input drain.", c->self);
914 }
915 }
916
917 /* ARGSUSED */
918 static void
919 channel_pre_output_draining(Channel *c, fd_set *readset, fd_set *writeset)
920 {
921 if (buffer_len(&c->output) == 0)
922 chan_mark_dead(c);
923 else
924 FD_SET(c->sock, writeset);
925 }
926
927 /*
928 * This is a special state for X11 authentication spoofing. An opened X11
929 * connection (when authentication spoofing is being done) remains in this
930 * state until the first packet has been completely read. The authentication
931 * data in that packet is then substituted by the real data if it matches the
932 * fake data, and the channel is put into normal mode.
933 * XXX All this happens at the client side.
934 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
935 */
936 static int
937 x11_open_helper(Buffer *b)
938 {
939 u_char *ucp;
940 u_int proto_len, data_len;
941
942 /* Check if the fixed size part of the packet is in buffer. */
943 if (buffer_len(b) < 12)
944 return 0;
945
946 /* Parse the lengths of variable-length fields. */
947 ucp = buffer_ptr(b);
948 if (ucp[0] == 0x42) { /* Byte order MSB first. */
949 proto_len = 256 * ucp[6] + ucp[7];
950 data_len = 256 * ucp[8] + ucp[9];
951 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
952 proto_len = ucp[6] + 256 * ucp[7];
953 data_len = ucp[8] + 256 * ucp[9];
954 } else {
955 debug2("Initial X11 packet contains bad byte order byte: 0x%x",
956 ucp[0]);
957 return -1;
958 }
959
960 /* Check if the whole packet is in buffer. */
961 if (buffer_len(b) <
962 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
963 return 0;
964
965 /* Check if authentication protocol matches. */
966 if (proto_len != strlen(x11_saved_proto) ||
967 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
968 debug2("X11 connection uses different authentication protocol.");
969 return -1;
970 }
971 /* Check if authentication data matches our fake data. */
972 if (data_len != x11_fake_data_len ||
973 timingsafe_bcmp(ucp + 12 + ((proto_len + 3) & ~3),
974 x11_fake_data, x11_fake_data_len) != 0) {
975 debug2("X11 auth data does not match fake data.");
976 return -1;
977 }
978 /* Check fake data length */
979 if (x11_fake_data_len != x11_saved_data_len) {
980 error("X11 fake_data_len %d != saved_data_len %d",
981 x11_fake_data_len, x11_saved_data_len);
982 return -1;
983 }
984 /*
985 * Received authentication protocol and data match
986 * our fake data. Substitute the fake data with real
987 * data.
988 */
989 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
990 x11_saved_data, x11_saved_data_len);
991 return 1;
992 }
993
994 static void
995 channel_pre_x11_open_13(Channel *c, fd_set *readset, fd_set *writeset)
996 {
997 int ret = x11_open_helper(&c->output);
998
999 if (ret == 1) {
1000 /* Start normal processing for the channel. */
1001 c->type = SSH_CHANNEL_OPEN;
1002 channel_pre_open_13(c, readset, writeset);
1003 } else if (ret == -1) {
1004 /*
1005 * We have received an X11 connection that has bad
1006 * authentication information.
1007 */
1008 logit("X11 connection rejected because of wrong authentication.");
1009 buffer_clear(&c->input);
1010 buffer_clear(&c->output);
1011 channel_close_fd(&c->sock);
1012 c->sock = -1;
1013 c->type = SSH_CHANNEL_CLOSED;
1014 packet_start(SSH_MSG_CHANNEL_CLOSE);
1015 packet_put_int(c->remote_id);
1016 packet_send();
1017 }
1018 }
1019
1020 static void
1021 channel_pre_x11_open(Channel *c, fd_set *readset, fd_set *writeset)
1022 {
1023 int ret = x11_open_helper(&c->output);
1024
1025 /* c->force_drain = 1; */
1026
1027 if (ret == 1) {
1028 c->type = SSH_CHANNEL_OPEN;
1029 channel_pre_open(c, readset, writeset);
1030 } else if (ret == -1) {
1031 logit("X11 connection rejected because of wrong authentication.");
1032 debug2("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
1033 chan_read_failed(c);
1034 buffer_clear(&c->input);
1035 chan_ibuf_empty(c);
1036 buffer_clear(&c->output);
1037 /* for proto v1, the peer will send an IEOF */
1038 if (compat20)
1039 chan_write_failed(c);
1040 else
1041 c->type = SSH_CHANNEL_OPEN;
1042 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
1043 }
1044 }
1045
1046 static void
1047 channel_pre_mux_client(Channel *c, fd_set *readset, fd_set *writeset)
1048 {
1049 if (c->istate == CHAN_INPUT_OPEN && !c->mux_pause &&
1050 buffer_check_alloc(&c->input, CHAN_RBUF))
1051 FD_SET(c->rfd, readset);
1052 if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1053 /* clear buffer immediately (discard any partial packet) */
1054 buffer_clear(&c->input);
1055 chan_ibuf_empty(c);
1056 /* Start output drain. XXX just kill chan? */
1057 chan_rcvd_oclose(c);
1058 }
1059 if (c->ostate == CHAN_OUTPUT_OPEN ||
1060 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
1061 if (buffer_len(&c->output) > 0)
1062 FD_SET(c->wfd, writeset);
1063 else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN)
1064 chan_obuf_empty(c);
1065 }
1066 }
1067
1068 /* try to decode a socks4 header */
1069 /* ARGSUSED */
1070 static int
1071 channel_decode_socks4(Channel *c, fd_set *readset, fd_set *writeset)
1072 {
1073 char *p, *host;
1074 u_int len, have, i, found, need;
1075 char username[256];
1076 struct {
1077 u_int8_t version;
1078 u_int8_t command;
1079 u_int16_t dest_port;
1080 struct in_addr dest_addr;
1081 } s4_req, s4_rsp;
1082
1083 debug2("channel %d: decode socks4", c->self);
1084
1085 have = buffer_len(&c->input);
1086 len = sizeof(s4_req);
1087 if (have < len)
1088 return 0;
1089 p = buffer_ptr(&c->input);
1090
1091 need = 1;
1092 /* SOCKS4A uses an invalid IP address 0.0.0.x */
1093 if (p[4] == 0 && p[5] == 0 && p[6] == 0 && p[7] != 0) {
1094 debug2("channel %d: socks4a request", c->self);
1095 /* ... and needs an extra string (the hostname) */
1096 need = 2;
1097 }
1098 /* Check for terminating NUL on the string(s) */
1099 for (found = 0, i = len; i < have; i++) {
1100 if (p[i] == '\0') {
1101 found++;
1102 if (found == need)
1103 break;
1104 }
1105 if (i > 1024) {
1106 /* the peer is probably sending garbage */
1107 debug("channel %d: decode socks4: too long",
1108 c->self);
1109 return -1;
1110 }
1111 }
1112 if (found < need)
1113 return 0;
1114 buffer_get(&c->input, (char *)&s4_req.version, 1);
1115 buffer_get(&c->input, (char *)&s4_req.command, 1);
1116 buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
1117 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
1118 have = buffer_len(&c->input);
1119 p = buffer_ptr(&c->input);
1120 if (memchr(p, '\0', have) == NULL)
1121 fatal("channel %d: decode socks4: user not nul terminated",
1122 c->self);
1123 len = strlen(p);
1124 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
1125 len++; /* trailing '\0' */
1126 if (len > have)
1127 fatal("channel %d: decode socks4: len %d > have %d",
1128 c->self, len, have);
1129 strlcpy(username, p, sizeof(username));
1130 buffer_consume(&c->input, len);
1131
1132 free(c->path);
1133 c->path = NULL;
1134 if (need == 1) { /* SOCKS4: one string */
1135 host = inet_ntoa(s4_req.dest_addr);
1136 c->path = xstrdup(host);
1137 } else { /* SOCKS4A: two strings */
1138 have = buffer_len(&c->input);
1139 p = buffer_ptr(&c->input);
1140 len = strlen(p);
1141 debug2("channel %d: decode socks4a: host %s/%d",
1142 c->self, p, len);
1143 len++; /* trailing '\0' */
1144 if (len > have)
1145 fatal("channel %d: decode socks4a: len %d > have %d",
1146 c->self, len, have);
1147 if (len > NI_MAXHOST) {
1148 error("channel %d: hostname \"%.100s\" too long",
1149 c->self, p);
1150 return -1;
1151 }
1152 c->path = xstrdup(p);
1153 buffer_consume(&c->input, len);
1154 }
1155 c->host_port = ntohs(s4_req.dest_port);
1156
1157 debug2("channel %d: dynamic request: socks4 host %s port %u command %u",
1158 c->self, c->path, c->host_port, s4_req.command);
1159
1160 if (s4_req.command != 1) {
1161 debug("channel %d: cannot handle: %s cn %d",
1162 c->self, need == 1 ? "SOCKS4" : "SOCKS4A", s4_req.command);
1163 return -1;
1164 }
1165 s4_rsp.version = 0; /* vn: 0 for reply */
1166 s4_rsp.command = 90; /* cd: req granted */
1167 s4_rsp.dest_port = 0; /* ignored */
1168 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
1169 buffer_append(&c->output, &s4_rsp, sizeof(s4_rsp));
1170 return 1;
1171 }
1172
1173 /* try to decode a socks5 header */
1174 #define SSH_SOCKS5_AUTHDONE 0x1000
1175 #define SSH_SOCKS5_NOAUTH 0x00
1176 #define SSH_SOCKS5_IPV4 0x01
1177 #define SSH_SOCKS5_DOMAIN 0x03
1178 #define SSH_SOCKS5_IPV6 0x04
1179 #define SSH_SOCKS5_CONNECT 0x01
1180 #define SSH_SOCKS5_SUCCESS 0x00
1181
1182 /* ARGSUSED */
1183 static int
1184 channel_decode_socks5(Channel *c, fd_set *readset, fd_set *writeset)
1185 {
1186 struct {
1187 u_int8_t version;
1188 u_int8_t command;
1189 u_int8_t reserved;
1190 u_int8_t atyp;
1191 } s5_req, s5_rsp;
1192 u_int16_t dest_port;
1193 char dest_addr[255+1], ntop[INET6_ADDRSTRLEN];
1194 u_char *p;
1195 u_int have, need, i, found, nmethods, addrlen, af;
1196
1197 debug2("channel %d: decode socks5", c->self);
1198 p = buffer_ptr(&c->input);
1199 if (p[0] != 0x05)
1200 return -1;
1201 have = buffer_len(&c->input);
1202 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) {
1203 /* format: ver | nmethods | methods */
1204 if (have < 2)
1205 return 0;
1206 nmethods = p[1];
1207 if (have < nmethods + 2)
1208 return 0;
1209 /* look for method: "NO AUTHENTICATION REQUIRED" */
1210 for (found = 0, i = 2; i < nmethods + 2; i++) {
1211 if (p[i] == SSH_SOCKS5_NOAUTH) {
1212 found = 1;
1213 break;
1214 }
1215 }
1216 if (!found) {
1217 debug("channel %d: method SSH_SOCKS5_NOAUTH not found",
1218 c->self);
1219 return -1;
1220 }
1221 buffer_consume(&c->input, nmethods + 2);
1222 buffer_put_char(&c->output, 0x05); /* version */
1223 buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH); /* method */
1224 FD_SET(c->sock, writeset);
1225 c->flags |= SSH_SOCKS5_AUTHDONE;
1226 debug2("channel %d: socks5 auth done", c->self);
1227 return 0; /* need more */
1228 }
1229 debug2("channel %d: socks5 post auth", c->self);
1230 if (have < sizeof(s5_req)+1)
1231 return 0; /* need more */
1232 memcpy(&s5_req, p, sizeof(s5_req));
1233 if (s5_req.version != 0x05 ||
1234 s5_req.command != SSH_SOCKS5_CONNECT ||
1235 s5_req.reserved != 0x00) {
1236 debug2("channel %d: only socks5 connect supported", c->self);
1237 return -1;
1238 }
1239 switch (s5_req.atyp){
1240 case SSH_SOCKS5_IPV4:
1241 addrlen = 4;
1242 af = AF_INET;
1243 break;
1244 case SSH_SOCKS5_DOMAIN:
1245 addrlen = p[sizeof(s5_req)];
1246 af = -1;
1247 break;
1248 case SSH_SOCKS5_IPV6:
1249 addrlen = 16;
1250 af = AF_INET6;
1251 break;
1252 default:
1253 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp);
1254 return -1;
1255 }
1256 need = sizeof(s5_req) + addrlen + 2;
1257 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1258 need++;
1259 if (have < need)
1260 return 0;
1261 buffer_consume(&c->input, sizeof(s5_req));
1262 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1263 buffer_consume(&c->input, 1); /* host string length */
1264 buffer_get(&c->input, &dest_addr, addrlen);
1265 buffer_get(&c->input, (char *)&dest_port, 2);
1266 dest_addr[addrlen] = '\0';
1267 free(c->path);
1268 c->path = NULL;
1269 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) {
1270 if (addrlen >= NI_MAXHOST) {
1271 error("channel %d: dynamic request: socks5 hostname "
1272 "\"%.100s\" too long", c->self, dest_addr);
1273 return -1;
1274 }
1275 c->path = xstrdup(dest_addr);
1276 } else {
1277 if (inet_ntop(af, dest_addr, ntop, sizeof(ntop)) == NULL)
1278 return -1;
1279 c->path = xstrdup(ntop);
1280 }
1281 c->host_port = ntohs(dest_port);
1282
1283 debug2("channel %d: dynamic request: socks5 host %s port %u command %u",
1284 c->self, c->path, c->host_port, s5_req.command);
1285
1286 s5_rsp.version = 0x05;
1287 s5_rsp.command = SSH_SOCKS5_SUCCESS;
1288 s5_rsp.reserved = 0; /* ignored */
1289 s5_rsp.atyp = SSH_SOCKS5_IPV4;
1290 dest_port = 0; /* ignored */
1291
1292 buffer_append(&c->output, &s5_rsp, sizeof(s5_rsp));
1293 buffer_put_int(&c->output, ntohl(INADDR_ANY)); /* bind address */
1294 buffer_append(&c->output, &dest_port, sizeof(dest_port));
1295 return 1;
1296 }
1297
1298 Channel *
1299 channel_connect_stdio_fwd(const char *host_to_connect, u_short port_to_connect,
1300 int in, int out)
1301 {
1302 Channel *c;
1303
1304 debug("channel_connect_stdio_fwd %s:%d", host_to_connect,
1305 port_to_connect);
1306
1307 c = channel_new("stdio-forward", SSH_CHANNEL_OPENING, in, out,
1308 -1, CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
1309 0, "stdio-forward", /*nonblock*/0);
1310
1311 c->path = xstrdup(host_to_connect);
1312 c->host_port = port_to_connect;
1313 c->listening_port = 0;
1314 c->force_drain = 1;
1315
1316 channel_register_fds(c, in, out, -1, 0, 1, 0);
1317 port_open_helper(c, "direct-tcpip");
1318
1319 return c;
1320 }
1321
1322 /* dynamic port forwarding */
1323 static void
1324 channel_pre_dynamic(Channel *c, fd_set *readset, fd_set *writeset)
1325 {
1326 u_char *p;
1327 u_int have;
1328 int ret;
1329
1330 have = buffer_len(&c->input);
1331 debug2("channel %d: pre_dynamic: have %d", c->self, have);
1332 /* buffer_dump(&c->input); */
1333 /* check if the fixed size part of the packet is in buffer. */
1334 if (have < 3) {
1335 /* need more */
1336 FD_SET(c->sock, readset);
1337 return;
1338 }
1339 /* try to guess the protocol */
1340 p = buffer_ptr(&c->input);
1341 switch (p[0]) {
1342 case 0x04:
1343 ret = channel_decode_socks4(c, readset, writeset);
1344 break;
1345 case 0x05:
1346 ret = channel_decode_socks5(c, readset, writeset);
1347 break;
1348 default:
1349 ret = -1;
1350 break;
1351 }
1352 if (ret < 0) {
1353 chan_mark_dead(c);
1354 } else if (ret == 0) {
1355 debug2("channel %d: pre_dynamic: need more", c->self);
1356 /* need more */
1357 FD_SET(c->sock, readset);
1358 } else {
1359 /* switch to the next state */
1360 c->type = SSH_CHANNEL_OPENING;
1361 port_open_helper(c, "direct-tcpip");
1362 }
1363 }
1364
1365 /* This is our fake X11 server socket. */
1366 /* ARGSUSED */
1367 static void
1368 channel_post_x11_listener(Channel *c, fd_set *readset, fd_set *writeset)
1369 {
1370 Channel *nc;
1371 struct sockaddr_storage addr;
1372 int newsock, oerrno;
1373 socklen_t addrlen;
1374 char buf[16384], *remote_ipaddr;
1375 int remote_port;
1376
1377 if (FD_ISSET(c->sock, readset)) {
1378 debug("X11 connection requested.");
1379 addrlen = sizeof(addr);
1380 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1381 if (c->single_connection) {
1382 oerrno = errno;
1383 debug2("single_connection: closing X11 listener.");
1384 channel_close_fd(&c->sock);
1385 chan_mark_dead(c);
1386 errno = oerrno;
1387 }
1388 if (newsock < 0) {
1389 if (errno != EINTR && errno != EWOULDBLOCK &&
1390 errno != ECONNABORTED)
1391 error("accept: %.100s", strerror(errno));
1392 if (errno == EMFILE || errno == ENFILE)
1393 c->notbefore = monotime() + 1;
1394 return;
1395 }
1396 set_nodelay(newsock);
1397 remote_ipaddr = get_peer_ipaddr(newsock);
1398 remote_port = get_peer_port(newsock);
1399 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1400 remote_ipaddr, remote_port);
1401
1402 nc = channel_new("accepted x11 socket",
1403 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1404 c->local_window_max, c->local_maxpacket, 0, buf, 1);
1405 if (compat20) {
1406 packet_start(SSH2_MSG_CHANNEL_OPEN);
1407 packet_put_cstring("x11");
1408 packet_put_int(nc->self);
1409 packet_put_int(nc->local_window_max);
1410 packet_put_int(nc->local_maxpacket);
1411 /* originator ipaddr and port */
1412 packet_put_cstring(remote_ipaddr);
1413 if (datafellows & SSH_BUG_X11FWD) {
1414 debug2("ssh2 x11 bug compat mode");
1415 } else {
1416 packet_put_int(remote_port);
1417 }
1418 packet_send();
1419 } else {
1420 packet_start(SSH_SMSG_X11_OPEN);
1421 packet_put_int(nc->self);
1422 if (packet_get_protocol_flags() &
1423 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1424 packet_put_cstring(buf);
1425 packet_send();
1426 }
1427 free(remote_ipaddr);
1428 }
1429 }
1430
1431 static void
1432 port_open_helper(Channel *c, char *rtype)
1433 {
1434 char buf[1024];
1435 char *local_ipaddr = get_local_ipaddr(c->sock);
1436 int local_port = c->sock == -1 ? 65536 : get_sock_port(c->sock, 1);
1437 char *remote_ipaddr = get_peer_ipaddr(c->sock);
1438 int remote_port = get_peer_port(c->sock);
1439
1440 if (remote_port == -1) {
1441 /* Fake addr/port to appease peers that validate it (Tectia) */
1442 free(remote_ipaddr);
1443 remote_ipaddr = xstrdup("127.0.0.1");
1444 remote_port = 65535;
1445 }
1446
1447 snprintf(buf, sizeof buf,
1448 "%s: listening port %d for %.100s port %d, "
1449 "connect from %.200s port %d to %.100s port %d",
1450 rtype, c->listening_port, c->path, c->host_port,
1451 remote_ipaddr, remote_port, local_ipaddr, local_port);
1452
1453 free(c->remote_name);
1454 c->remote_name = xstrdup(buf);
1455
1456 if (compat20) {
1457 packet_start(SSH2_MSG_CHANNEL_OPEN);
1458 packet_put_cstring(rtype);
1459 packet_put_int(c->self);
1460 packet_put_int(c->local_window_max);
1461 packet_put_int(c->local_maxpacket);
1462 if (strcmp(rtype, "direct-tcpip") == 0) {
1463 /* target host, port */
1464 packet_put_cstring(c->path);
1465 packet_put_int(c->host_port);
1466 } else if (strcmp(rtype, "direct-streamlocal@openssh.com") == 0) {
1467 /* target path */
1468 packet_put_cstring(c->path);
1469 } else if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) {
1470 /* listen path */
1471 packet_put_cstring(c->path);
1472 } else {
1473 /* listen address, port */
1474 packet_put_cstring(c->path);
1475 packet_put_int(local_port);
1476 }
1477 if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) {
1478 /* reserved for future owner/mode info */
1479 packet_put_cstring("");
1480 } else {
1481 /* originator host and port */
1482 packet_put_cstring(remote_ipaddr);
1483 packet_put_int((u_int)remote_port);
1484 }
1485 packet_send();
1486 } else {
1487 packet_start(SSH_MSG_PORT_OPEN);
1488 packet_put_int(c->self);
1489 packet_put_cstring(c->path);
1490 packet_put_int(c->host_port);
1491 if (packet_get_protocol_flags() &
1492 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1493 packet_put_cstring(c->remote_name);
1494 packet_send();
1495 }
1496 free(remote_ipaddr);
1497 free(local_ipaddr);
1498 }
1499
1500 static void
1501 channel_set_reuseaddr(int fd)
1502 {
1503 int on = 1;
1504
1505 /*
1506 * Set socket options.
1507 * Allow local port reuse in TIME_WAIT.
1508 */
1509 if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1)
1510 error("setsockopt SO_REUSEADDR fd %d: %s", fd, strerror(errno));
1511 }
1512
1513 /*
1514 * This socket is listening for connections to a forwarded TCP/IP port.
1515 */
1516 /* ARGSUSED */
1517 static void
1518 channel_post_port_listener(Channel *c, fd_set *readset, fd_set *writeset)
1519 {
1520 Channel *nc;
1521 struct sockaddr_storage addr;
1522 int newsock, nextstate;
1523 socklen_t addrlen;
1524 char *rtype;
1525
1526 if (FD_ISSET(c->sock, readset)) {
1527 debug("Connection to port %d forwarding "
1528 "to %.100s port %d requested.",
1529 c->listening_port, c->path, c->host_port);
1530
1531 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1532 nextstate = SSH_CHANNEL_OPENING;
1533 rtype = "forwarded-tcpip";
1534 } else if (c->type == SSH_CHANNEL_RUNIX_LISTENER) {
1535 nextstate = SSH_CHANNEL_OPENING;
1536 rtype = "forwarded-streamlocal@openssh.com";
1537 } else if (c->host_port == PORT_STREAMLOCAL) {
1538 nextstate = SSH_CHANNEL_OPENING;
1539 rtype = "direct-streamlocal@openssh.com";
1540 } else if (c->host_port == 0) {
1541 nextstate = SSH_CHANNEL_DYNAMIC;
1542 rtype = "dynamic-tcpip";
1543 } else {
1544 nextstate = SSH_CHANNEL_OPENING;
1545 rtype = "direct-tcpip";
1546 }
1547
1548 addrlen = sizeof(addr);
1549 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1550 if (newsock < 0) {
1551 if (errno != EINTR && errno != EWOULDBLOCK &&
1552 errno != ECONNABORTED)
1553 error("accept: %.100s", strerror(errno));
1554 if (errno == EMFILE || errno == ENFILE)
1555 c->notbefore = monotime() + 1;
1556 return;
1557 }
1558 if (c->host_port != PORT_STREAMLOCAL)
1559 set_nodelay(newsock);
1560 nc = channel_new(rtype, nextstate, newsock, newsock, -1,
1561 c->local_window_max, c->local_maxpacket, 0, rtype, 1);
1562 nc->listening_port = c->listening_port;
1563 nc->host_port = c->host_port;
1564 if (c->path != NULL)
1565 nc->path = xstrdup(c->path);
1566
1567 if (nextstate != SSH_CHANNEL_DYNAMIC)
1568 port_open_helper(nc, rtype);
1569 }
1570 }
1571
1572 /*
1573 * This is the authentication agent socket listening for connections from
1574 * clients.
1575 */
1576 /* ARGSUSED */
1577 static void
1578 channel_post_auth_listener(Channel *c, fd_set *readset, fd_set *writeset)
1579 {
1580 Channel *nc;
1581 int newsock;
1582 struct sockaddr_storage addr;
1583 socklen_t addrlen;
1584
1585 if (FD_ISSET(c->sock, readset)) {
1586 addrlen = sizeof(addr);
1587 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1588 if (newsock < 0) {
1589 error("accept from auth socket: %.100s",
1590 strerror(errno));
1591 if (errno == EMFILE || errno == ENFILE)
1592 c->notbefore = monotime() + 1;
1593 return;
1594 }
1595 nc = channel_new("accepted auth socket",
1596 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1597 c->local_window_max, c->local_maxpacket,
1598 0, "accepted auth socket", 1);
1599 if (compat20) {
1600 packet_start(SSH2_MSG_CHANNEL_OPEN);
1601 packet_put_cstring("auth-agent@openssh.com");
1602 packet_put_int(nc->self);
1603 packet_put_int(c->local_window_max);
1604 packet_put_int(c->local_maxpacket);
1605 } else {
1606 packet_start(SSH_SMSG_AGENT_OPEN);
1607 packet_put_int(nc->self);
1608 }
1609 packet_send();
1610 }
1611 }
1612
1613 /* ARGSUSED */
1614 static void
1615 channel_post_connecting(Channel *c, fd_set *readset, fd_set *writeset)
1616 {
1617 int err = 0, sock;
1618 socklen_t sz = sizeof(err);
1619
1620 if (FD_ISSET(c->sock, writeset)) {
1621 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) {
1622 err = errno;
1623 error("getsockopt SO_ERROR failed");
1624 }
1625 if (err == 0) {
1626 debug("channel %d: connected to %s port %d",
1627 c->self, c->connect_ctx.host, c->connect_ctx.port);
1628 channel_connect_ctx_free(&c->connect_ctx);
1629 c->type = SSH_CHANNEL_OPEN;
1630 if (compat20) {
1631 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1632 packet_put_int(c->remote_id);
1633 packet_put_int(c->self);
1634 packet_put_int(c->local_window);
1635 packet_put_int(c->local_maxpacket);
1636 } else {
1637 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1638 packet_put_int(c->remote_id);
1639 packet_put_int(c->self);
1640 }
1641 } else {
1642 debug("channel %d: connection failed: %s",
1643 c->self, strerror(err));
1644 /* Try next address, if any */
1645 if ((sock = connect_next(&c->connect_ctx)) > 0) {
1646 close(c->sock);
1647 c->sock = c->rfd = c->wfd = sock;
1648 channel_max_fd = channel_find_maxfd();
1649 return;
1650 }
1651 /* Exhausted all addresses */
1652 error("connect_to %.100s port %d: failed.",
1653 c->connect_ctx.host, c->connect_ctx.port);
1654 channel_connect_ctx_free(&c->connect_ctx);
1655 if (compat20) {
1656 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1657 packet_put_int(c->remote_id);
1658 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1659 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1660 packet_put_cstring(strerror(err));
1661 packet_put_cstring("");
1662 }
1663 } else {
1664 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1665 packet_put_int(c->remote_id);
1666 }
1667 chan_mark_dead(c);
1668 }
1669 packet_send();
1670 }
1671 }
1672
1673 /* ARGSUSED */
1674 static int
1675 channel_handle_rfd(Channel *c, fd_set *readset, fd_set *writeset)
1676 {
1677 char buf[CHAN_RBUF];
1678 int len, force;
1679
1680 force = c->isatty && c->detach_close && c->istate != CHAN_INPUT_CLOSED;
1681 if (c->rfd != -1 && (force || FD_ISSET(c->rfd, readset))) {
1682 errno = 0;
1683 len = read(c->rfd, buf, sizeof(buf));
1684 if (len < 0 && (errno == EINTR ||
1685 ((errno == EAGAIN || errno == EWOULDBLOCK) && !force)))
1686 return 1;
1687 #ifndef PTY_ZEROREAD
1688 if (len <= 0) {
1689 #else
1690 if ((!c->isatty && len <= 0) ||
1691 (c->isatty && (len < 0 || (len == 0 && errno != 0)))) {
1692 #endif
1693 debug2("channel %d: read<=0 rfd %d len %d",
1694 c->self, c->rfd, len);
1695 if (c->type != SSH_CHANNEL_OPEN) {
1696 debug2("channel %d: not open", c->self);
1697 chan_mark_dead(c);
1698 return -1;
1699 } else if (compat13) {
1700 buffer_clear(&c->output);
1701 c->type = SSH_CHANNEL_INPUT_DRAINING;
1702 debug2("channel %d: input draining.", c->self);
1703 } else {
1704 chan_read_failed(c);
1705 }
1706 return -1;
1707 }
1708 if (c->input_filter != NULL) {
1709 if (c->input_filter(c, buf, len) == -1) {
1710 debug2("channel %d: filter stops", c->self);
1711 chan_read_failed(c);
1712 }
1713 } else if (c->datagram) {
1714 buffer_put_string(&c->input, buf, len);
1715 } else {
1716 buffer_append(&c->input, buf, len);
1717 }
1718 }
1719 return 1;
1720 }
1721
1722 /* ARGSUSED */
1723 static int
1724 channel_handle_wfd(Channel *c, fd_set *readset, fd_set *writeset)
1725 {
1726 struct termios tio;
1727 u_char *data = NULL, *buf;
1728 u_int dlen, olen = 0;
1729 int len;
1730
1731 /* Send buffered output data to the socket. */
1732 if (c->wfd != -1 &&
1733 FD_ISSET(c->wfd, writeset) &&
1734 buffer_len(&c->output) > 0) {
1735 olen = buffer_len(&c->output);
1736 if (c->output_filter != NULL) {
1737 if ((buf = c->output_filter(c, &data, &dlen)) == NULL) {
1738 debug2("channel %d: filter stops", c->self);
1739 if (c->type != SSH_CHANNEL_OPEN)
1740 chan_mark_dead(c);
1741 else
1742 chan_write_failed(c);
1743 return -1;
1744 }
1745 } else if (c->datagram) {
1746 buf = data = buffer_get_string(&c->output, &dlen);
1747 } else {
1748 buf = data = buffer_ptr(&c->output);
1749 dlen = buffer_len(&c->output);
1750 }
1751
1752 if (c->datagram) {
1753 /* ignore truncated writes, datagrams might get lost */
1754 len = write(c->wfd, buf, dlen);
1755 free(data);
1756 if (len < 0 && (errno == EINTR || errno == EAGAIN ||
1757 errno == EWOULDBLOCK))
1758 return 1;
1759 if (len <= 0) {
1760 if (c->type != SSH_CHANNEL_OPEN)
1761 chan_mark_dead(c);
1762 else
1763 chan_write_failed(c);
1764 return -1;
1765 }
1766 goto out;
1767 }
1768 #ifdef _AIX
1769 /* XXX: Later AIX versions can't push as much data to tty */
1770 if (compat20 && c->wfd_isatty)
1771 dlen = MIN(dlen, 8*1024);
1772 #endif
1773
1774 len = write(c->wfd, buf, dlen);
1775 if (len < 0 &&
1776 (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK))
1777 return 1;
1778 if (len <= 0) {
1779 if (c->type != SSH_CHANNEL_OPEN) {
1780 debug2("channel %d: not open", c->self);
1781 chan_mark_dead(c);
1782 return -1;
1783 } else if (compat13) {
1784 buffer_clear(&c->output);
1785 debug2("channel %d: input draining.", c->self);
1786 c->type = SSH_CHANNEL_INPUT_DRAINING;
1787 } else {
1788 chan_write_failed(c);
1789 }
1790 return -1;
1791 }
1792 #ifndef BROKEN_TCGETATTR_ICANON
1793 if (compat20 && c->isatty && dlen >= 1 && buf[0] != '\r') {
1794 if (tcgetattr(c->wfd, &tio) == 0 &&
1795 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1796 /*
1797 * Simulate echo to reduce the impact of
1798 * traffic analysis. We need to match the
1799 * size of a SSH2_MSG_CHANNEL_DATA message
1800 * (4 byte channel id + buf)
1801 */
1802 packet_send_ignore(4 + len);
1803 packet_send();
1804 }
1805 }
1806 #endif
1807 buffer_consume(&c->output, len);
1808 }
1809 out:
1810 if (compat20 && olen > 0)
1811 c->local_consumed += olen - buffer_len(&c->output);
1812 return 1;
1813 }
1814
1815 static int
1816 channel_handle_efd(Channel *c, fd_set *readset, fd_set *writeset)
1817 {
1818 char buf[CHAN_RBUF];
1819 int len;
1820
1821 /** XXX handle drain efd, too */
1822 if (c->efd != -1) {
1823 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1824 FD_ISSET(c->efd, writeset) &&
1825 buffer_len(&c->extended) > 0) {
1826 len = write(c->efd, buffer_ptr(&c->extended),
1827 buffer_len(&c->extended));
1828 debug2("channel %d: written %d to efd %d",
1829 c->self, len, c->efd);
1830 if (len < 0 && (errno == EINTR || errno == EAGAIN ||
1831 errno == EWOULDBLOCK))
1832 return 1;
1833 if (len <= 0) {
1834 debug2("channel %d: closing write-efd %d",
1835 c->self, c->efd);
1836 channel_close_fd(&c->efd);
1837 } else {
1838 buffer_consume(&c->extended, len);
1839 c->local_consumed += len;
1840 }
1841 } else if (c->efd != -1 &&
1842 (c->extended_usage == CHAN_EXTENDED_READ ||
1843 c->extended_usage == CHAN_EXTENDED_IGNORE) &&
1844 (c->detach_close || FD_ISSET(c->efd, readset))) {
1845 len = read(c->efd, buf, sizeof(buf));
1846 debug2("channel %d: read %d from efd %d",
1847 c->self, len, c->efd);
1848 if (len < 0 && (errno == EINTR || ((errno == EAGAIN ||
1849 errno == EWOULDBLOCK) && !c->detach_close)))
1850 return 1;
1851 if (len <= 0) {
1852 debug2("channel %d: closing read-efd %d",
1853 c->self, c->efd);
1854 channel_close_fd(&c->efd);
1855 } else {
1856 if (c->extended_usage == CHAN_EXTENDED_IGNORE) {
1857 debug3("channel %d: discard efd",
1858 c->self);
1859 } else
1860 buffer_append(&c->extended, buf, len);
1861 }
1862 }
1863 }
1864 return 1;
1865 }
1866
1867 static int
1868 channel_check_window(Channel *c)
1869 {
1870 if (c->type == SSH_CHANNEL_OPEN &&
1871 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1872 ((c->local_window_max - c->local_window >
1873 c->local_maxpacket*3) ||
1874 c->local_window < c->local_window_max/2) &&
1875 c->local_consumed > 0) {
1876 u_int addition = 0;
1877 /* adjust max window size if we are in a dynamic environment */
1878 if (c->dynamic_window && (c->tcpwinsz > c->local_window_max)) {
1879 /* grow the window somewhat aggressively to maintain pressure */
1880 addition = 1.5*(c->tcpwinsz - c->local_window_max);
1881 c->local_window_max += addition;
1882 }
1883 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1884 packet_put_int(c->remote_id);
1885 packet_put_int(c->local_consumed + addition);
1886 packet_send();
1887 debug2("channel %d: window %d sent adjust %d",
1888 c->self, c->local_window,
1889 c->local_consumed);
1890 c->local_window += c->local_consumed + addition;
1891 c->local_consumed = 0;
1892 }
1893 return 1;
1894 }
1895
1896 static void
1897 channel_post_open(Channel *c, fd_set *readset, fd_set *writeset)
1898 {
1899 channel_handle_rfd(c, readset, writeset);
1900 channel_handle_wfd(c, readset, writeset);
1901 if (!compat20)
1902 return;
1903 channel_handle_efd(c, readset, writeset);
1904 channel_check_window(c);
1905 }
1906
1907 static u_int
1908 read_mux(Channel *c, u_int need)
1909 {
1910 char buf[CHAN_RBUF];
1911 int len;
1912 u_int rlen;
1913
1914 if (buffer_len(&c->input) < need) {
1915 rlen = need - buffer_len(&c->input);
1916 len = read(c->rfd, buf, MIN(rlen, CHAN_RBUF));
1917 if (len <= 0) {
1918 if (errno != EINTR && errno != EAGAIN) {
1919 debug2("channel %d: ctl read<=0 rfd %d len %d",
1920 c->self, c->rfd, len);
1921 chan_read_failed(c);
1922 return 0;
1923 }
1924 } else
1925 buffer_append(&c->input, buf, len);
1926 }
1927 return buffer_len(&c->input);
1928 }
1929
1930 static void
1931 channel_post_mux_client(Channel *c, fd_set *readset, fd_set *writeset)
1932 {
1933 u_int need;
1934 ssize_t len;
1935
1936 if (!compat20)
1937 fatal("%s: entered with !compat20", __func__);
1938
1939 if (c->rfd != -1 && !c->mux_pause && FD_ISSET(c->rfd, readset) &&
1940 (c->istate == CHAN_INPUT_OPEN ||
1941 c->istate == CHAN_INPUT_WAIT_DRAIN)) {
1942 /*
1943 * Don't not read past the precise end of packets to
1944 * avoid disrupting fd passing.
1945 */
1946 if (read_mux(c, 4) < 4) /* read header */
1947 return;
1948 need = get_u32(buffer_ptr(&c->input));
1949 #define CHANNEL_MUX_MAX_PACKET (256 * 1024)
1950 if (need > CHANNEL_MUX_MAX_PACKET) {
1951 debug2("channel %d: packet too big %u > %u",
1952 c->self, CHANNEL_MUX_MAX_PACKET, need);
1953 chan_rcvd_oclose(c);
1954 return;
1955 }
1956 if (read_mux(c, need + 4) < need + 4) /* read body */
1957 return;
1958 if (c->mux_rcb(c) != 0) {
1959 debug("channel %d: mux_rcb failed", c->self);
1960 chan_mark_dead(c);
1961 return;
1962 }
1963 }
1964
1965 if (c->wfd != -1 && FD_ISSET(c->wfd, writeset) &&
1966 buffer_len(&c->output) > 0) {
1967 len = write(c->wfd, buffer_ptr(&c->output),
1968 buffer_len(&c->output));
1969 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1970 return;
1971 if (len <= 0) {
1972 chan_mark_dead(c);
1973 return;
1974 }
1975 buffer_consume(&c->output, len);
1976 }
1977 }
1978
1979 static void
1980 channel_post_mux_listener(Channel *c, fd_set *readset, fd_set *writeset)
1981 {
1982 Channel *nc;
1983 struct sockaddr_storage addr;
1984 socklen_t addrlen;
1985 int newsock;
1986 uid_t euid;
1987 gid_t egid;
1988
1989 if (!FD_ISSET(c->sock, readset))
1990 return;
1991
1992 debug("multiplexing control connection");
1993
1994 /*
1995 * Accept connection on control socket
1996 */
1997 memset(&addr, 0, sizeof(addr));
1998 addrlen = sizeof(addr);
1999 if ((newsock = accept(c->sock, (struct sockaddr*)&addr,
2000 &addrlen)) == -1) {
2001 error("%s accept: %s", __func__, strerror(errno));
2002 if (errno == EMFILE || errno == ENFILE)
2003 c->notbefore = monotime() + 1;
2004 return;
2005 }
2006
2007 if (getpeereid(newsock, &euid, &egid) < 0) {
2008 error("%s getpeereid failed: %s", __func__,
2009 strerror(errno));
2010 close(newsock);
2011 return;
2012 }
2013 if ((euid != 0) && (getuid() != euid)) {
2014 error("multiplex uid mismatch: peer euid %u != uid %u",
2015 (u_int)euid, (u_int)getuid());
2016 close(newsock);
2017 return;
2018 }
2019 nc = channel_new("multiplex client", SSH_CHANNEL_MUX_CLIENT,
2020 newsock, newsock, -1, c->local_window_max,
2021 c->local_maxpacket, 0, "mux-control", 1);
2022 nc->mux_rcb = c->mux_rcb;
2023 debug3("%s: new mux channel %d fd %d", __func__,
2024 nc->self, nc->sock);
2025 /* establish state */
2026 nc->mux_rcb(nc);
2027 /* mux state transitions must not elicit protocol messages */
2028 nc->flags |= CHAN_LOCAL;
2029 }
2030
2031 /* ARGSUSED */
2032 static void
2033 channel_post_output_drain_13(Channel *c, fd_set *readset, fd_set *writeset)
2034 {
2035 int len;
2036
2037 /* Send buffered output data to the socket. */
2038 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
2039 len = write(c->sock, buffer_ptr(&c->output),
2040 buffer_len(&c->output));
2041 if (len <= 0)
2042 buffer_clear(&c->output);
2043 else
2044 buffer_consume(&c->output, len);
2045 }
2046 }
2047
2048 static void
2049 channel_handler_init_20(void)
2050 {
2051 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
2052 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
2053 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
2054 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
2055 channel_pre[SSH_CHANNEL_UNIX_LISTENER] = &channel_pre_listener;
2056 channel_pre[SSH_CHANNEL_RUNIX_LISTENER] = &channel_pre_listener;
2057 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
2058 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
2059 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
2060 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
2061 channel_pre[SSH_CHANNEL_MUX_LISTENER] = &channel_pre_listener;
2062 channel_pre[SSH_CHANNEL_MUX_CLIENT] = &channel_pre_mux_client;
2063
2064 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
2065 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
2066 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
2067 channel_post[SSH_CHANNEL_UNIX_LISTENER] = &channel_post_port_listener;
2068 channel_post[SSH_CHANNEL_RUNIX_LISTENER] = &channel_post_port_listener;
2069 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
2070 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
2071 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
2072 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
2073 channel_post[SSH_CHANNEL_MUX_LISTENER] = &channel_post_mux_listener;
2074 channel_post[SSH_CHANNEL_MUX_CLIENT] = &channel_post_mux_client;
2075 }
2076
2077 static void
2078 channel_handler_init_13(void)
2079 {
2080 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
2081 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
2082 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
2083 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
2084 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
2085 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
2086 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
2087 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
2088 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
2089
2090 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
2091 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
2092 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
2093 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
2094 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
2095 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
2096 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
2097 }
2098
2099 static void
2100 channel_handler_init_15(void)
2101 {
2102 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
2103 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
2104 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
2105 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
2106 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
2107 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
2108 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
2109
2110 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
2111 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
2112 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
2113 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
2114 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
2115 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
2116 }
2117
2118 static void
2119 channel_handler_init(void)
2120 {
2121 int i;
2122
2123 for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
2124 channel_pre[i] = NULL;
2125 channel_post[i] = NULL;
2126 }
2127 if (compat20)
2128 channel_handler_init_20();
2129 else if (compat13)
2130 channel_handler_init_13();
2131 else
2132 channel_handler_init_15();
2133 }
2134
2135 /* gc dead channels */
2136 static void
2137 channel_garbage_collect(Channel *c)
2138 {
2139 if (c == NULL)
2140 return;
2141 if (c->detach_user != NULL) {
2142 if (!chan_is_dead(c, c->detach_close))
2143 return;
2144 debug2("channel %d: gc: notify user", c->self);
2145 c->detach_user(c->self, NULL);
2146 /* if we still have a callback */
2147 if (c->detach_user != NULL)
2148 return;
2149 debug2("channel %d: gc: user detached", c->self);
2150 }
2151 if (!chan_is_dead(c, 1))
2152 return;
2153 debug2("channel %d: garbage collecting", c->self);
2154 channel_free(c);
2155 }
2156
2157 static void
2158 channel_handler(chan_fn *ftab[], fd_set *readset, fd_set *writeset,
2159 time_t *unpause_secs)
2160 {
2161 static int did_init = 0;
2162 u_int i, oalloc;
2163 Channel *c;
2164 time_t now;
2165
2166 if (!did_init) {
2167 channel_handler_init();
2168 did_init = 1;
2169 }
2170 now = monotime();
2171 if (unpause_secs != NULL)
2172 *unpause_secs = 0;
2173 for (i = 0, oalloc = channels_alloc; i < oalloc; i++) {
2174 c = channels[i];
2175 if (c == NULL)
2176 continue;
2177 if (c->delayed) {
2178 if (ftab == channel_pre)
2179 c->delayed = 0;
2180 else
2181 continue;
2182 }
2183 if (ftab[c->type] != NULL) {
2184 /*
2185 * Run handlers that are not paused.
2186 */
2187 if (c->notbefore <= now)
2188 (*ftab[c->type])(c, readset, writeset);
2189 else if (unpause_secs != NULL) {
2190 /*
2191 * Collect the time that the earliest
2192 * channel comes off pause.
2193 */
2194 debug3("%s: chan %d: skip for %d more seconds",
2195 __func__, c->self,
2196 (int)(c->notbefore - now));
2197 if (*unpause_secs == 0 ||
2198 (c->notbefore - now) < *unpause_secs)
2199 *unpause_secs = c->notbefore - now;
2200 }
2201 }
2202 channel_garbage_collect(c);
2203 }
2204 if (unpause_secs != NULL && *unpause_secs != 0)
2205 debug3("%s: first channel unpauses in %d seconds",
2206 __func__, (int)*unpause_secs);
2207 }
2208
2209 /*
2210 * Allocate/update select bitmasks and add any bits relevant to channels in
2211 * select bitmasks.
2212 */
2213 void
2214 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
2215 u_int *nallocp, time_t *minwait_secs, int rekeying)
2216 {
2217 u_int n, sz, nfdset;
2218
2219 n = MAX(*maxfdp, channel_max_fd);
2220
2221 nfdset = howmany(n+1, NFDBITS);
2222 /* Explicitly test here, because xrealloc isn't always called */
2223 if (nfdset && SIZE_T_MAX / nfdset < sizeof(fd_mask))
2224 fatal("channel_prepare_select: max_fd (%d) is too large", n);
2225 sz = nfdset * sizeof(fd_mask);
2226
2227 /* perhaps check sz < nalloc/2 and shrink? */
2228 if (*readsetp == NULL || sz > *nallocp) {
2229 *readsetp = xrealloc(*readsetp, nfdset, sizeof(fd_mask));
2230 *writesetp = xrealloc(*writesetp, nfdset, sizeof(fd_mask));
2231 *nallocp = sz;
2232 }
2233 *maxfdp = n;
2234 memset(*readsetp, 0, sz);
2235 memset(*writesetp, 0, sz);
2236
2237 if (!rekeying)
2238 channel_handler(channel_pre, *readsetp, *writesetp,
2239 minwait_secs);
2240 }
2241
2242 /*
2243 * After select, perform any appropriate operations for channels which have
2244 * events pending.
2245 */
2246 void
2247 channel_after_select(fd_set *readset, fd_set *writeset)
2248 {
2249 channel_handler(channel_post, readset, writeset, NULL);
2250 }
2251
2252
2253 /* If there is data to send to the connection, enqueue some of it now. */
2254 int
2255 channel_output_poll(void)
2256 {
2257 Channel *c;
2258 u_int i, len;
2259 int packet_length = 0;
2260
2261 for (i = 0; i < channels_alloc; i++) {
2262 c = channels[i];
2263 if (c == NULL)
2264 continue;
2265
2266 /*
2267 * We are only interested in channels that can have buffered
2268 * incoming data.
2269 */
2270 if (compat13) {
2271 if (c->type != SSH_CHANNEL_OPEN &&
2272 c->type != SSH_CHANNEL_INPUT_DRAINING)
2273 continue;
2274 } else {
2275 if (c->type != SSH_CHANNEL_OPEN)
2276 continue;
2277 }
2278 if (compat20 &&
2279 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
2280 /* XXX is this true? */
2281 debug3("channel %d: will not send data after close", c->self);
2282 continue;
2283 }
2284
2285 /* Get the amount of buffered data for this channel. */
2286 if ((c->istate == CHAN_INPUT_OPEN ||
2287 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
2288 (len = buffer_len(&c->input)) > 0) {
2289 if (c->datagram) {
2290 if (len > 0) {
2291 u_char *data;
2292 u_int dlen;
2293
2294 data = buffer_get_string(&c->input,
2295 &dlen);
2296 if (dlen > c->remote_window ||
2297 dlen > c->remote_maxpacket) {
2298 debug("channel %d: datagram "
2299 "too big for channel",
2300 c->self);
2301 free(data);
2302 continue;
2303 }
2304 packet_start(SSH2_MSG_CHANNEL_DATA);
2305 packet_put_int(c->remote_id);
2306 packet_put_string(data, dlen);
2307 packet_length = packet_send();
2308 c->remote_window -= dlen + 4;
2309 free(data);
2310 }
2311 continue;
2312 }
2313 /*
2314 * Send some data for the other side over the secure
2315 * connection.
2316 */
2317 if (compat20) {
2318 if (len > c->remote_window)
2319 len = c->remote_window;
2320 if (len > c->remote_maxpacket)
2321 len = c->remote_maxpacket;
2322 } else {
2323 if (packet_is_interactive()) {
2324 if (len > 1024)
2325 len = 512;
2326 } else {
2327 /* Keep the packets at reasonable size. */
2328 if (len > packet_get_maxsize()/2)
2329 len = packet_get_maxsize()/2;
2330 }
2331 }
2332 if (len > 0) {
2333 packet_start(compat20 ?
2334 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
2335 packet_put_int(c->remote_id);
2336 packet_put_string(buffer_ptr(&c->input), len);
2337 packet_length = packet_send();
2338 buffer_consume(&c->input, len);
2339 c->remote_window -= len;
2340 }
2341 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
2342 if (compat13)
2343 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
2344 /*
2345 * input-buffer is empty and read-socket shutdown:
2346 * tell peer, that we will not send more data: send IEOF.
2347 * hack for extended data: delay EOF if EFD still in use.
2348 */
2349 if (CHANNEL_EFD_INPUT_ACTIVE(c))
2350 debug2("channel %d: ibuf_empty delayed efd %d/(%d)",
2351 c->self, c->efd, buffer_len(&c->extended));
2352 else
2353 chan_ibuf_empty(c);
2354 }
2355 /* Send extended data, i.e. stderr */
2356 if (compat20 &&
2357 !(c->flags & CHAN_EOF_SENT) &&
2358 c->remote_window > 0 &&
2359 (len = buffer_len(&c->extended)) > 0 &&
2360 c->extended_usage == CHAN_EXTENDED_READ) {
2361 debug2("channel %d: rwin %u elen %u euse %d",
2362 c->self, c->remote_window, buffer_len(&c->extended),
2363 c->extended_usage);
2364 if (len > c->remote_window)
2365 len = c->remote_window;
2366 if (len > c->remote_maxpacket)
2367 len = c->remote_maxpacket;
2368 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
2369 packet_put_int(c->remote_id);
2370 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
2371 packet_put_string(buffer_ptr(&c->extended), len);
2372 packet_length = packet_send();
2373 buffer_consume(&c->extended, len);
2374 c->remote_window -= len;
2375 debug2("channel %d: sent ext data %d", c->self, len);
2376 }
2377 }
2378 return (packet_length);
2379 }
2380
2381
2382 /* -- protocol input */
2383
2384 /* ARGSUSED */
2385 void
2386 channel_input_data(int type, u_int32_t seq, void *ctxt)
2387 {
2388 int id;
2389 const u_char *data;
2390 u_int data_len, win_len;
2391 Channel *c;
2392
2393 /* Get the channel number and verify it. */
2394 id = packet_get_int();
2395 c = channel_lookup(id);
2396 if (c == NULL)
2397 packet_disconnect("Received data for nonexistent channel %d.", id);
2398
2399 /* Ignore any data for non-open channels (might happen on close) */
2400 if (c->type != SSH_CHANNEL_OPEN &&
2401 c->type != SSH_CHANNEL_X11_OPEN)
2402 return;
2403
2404 /* Get the data. */
2405 data = packet_get_string_ptr(&data_len);
2406 win_len = data_len;
2407 if (c->datagram)
2408 win_len += 4; /* string length header */
2409
2410 /*
2411 * Ignore data for protocol > 1.3 if output end is no longer open.
2412 * For protocol 2 the sending side is reducing its window as it sends
2413 * data, so we must 'fake' consumption of the data in order to ensure
2414 * that window updates are sent back. Otherwise the connection might
2415 * deadlock.
2416 */
2417 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) {
2418 if (compat20) {
2419 c->local_window -= win_len;
2420 c->local_consumed += win_len;
2421 }
2422 return;
2423 }
2424
2425 if (compat20) {
2426 if (win_len > c->local_maxpacket) {
2427 logit("channel %d: rcvd big packet %d, maxpack %d",
2428 c->self, win_len, c->local_maxpacket);
2429 }
2430 if (win_len > c->local_window) {
2431 logit("channel %d: rcvd too much data %d, win %d",
2432 c->self, win_len, c->local_window);
2433 return;
2434 }
2435 c->local_window -= win_len;
2436 }
2437 if (c->datagram)
2438 buffer_put_string(&c->output, data, data_len);
2439 else
2440 buffer_append(&c->output, data, data_len);
2441 packet_check_eom();
2442 }
2443
2444 /* ARGSUSED */
2445 void
2446 channel_input_extended_data(int type, u_int32_t seq, void *ctxt)
2447 {
2448 int id;
2449 char *data;
2450 u_int data_len, tcode;
2451 Channel *c;
2452
2453 /* Get the channel number and verify it. */
2454 id = packet_get_int();
2455 c = channel_lookup(id);
2456
2457 if (c == NULL)
2458 packet_disconnect("Received extended_data for bad channel %d.", id);
2459 if (c->type != SSH_CHANNEL_OPEN) {
2460 logit("channel %d: ext data for non open", id);
2461 return;
2462 }
2463 if (c->flags & CHAN_EOF_RCVD) {
2464 if (datafellows & SSH_BUG_EXTEOF)
2465 debug("channel %d: accepting ext data after eof", id);
2466 else
2467 packet_disconnect("Received extended_data after EOF "
2468 "on channel %d.", id);
2469 }
2470 tcode = packet_get_int();
2471 if (c->efd == -1 ||
2472 c->extended_usage != CHAN_EXTENDED_WRITE ||
2473 tcode != SSH2_EXTENDED_DATA_STDERR) {
2474 logit("channel %d: bad ext data", c->self);
2475 return;
2476 }
2477 data = packet_get_string(&data_len);
2478 packet_check_eom();
2479 if (data_len > c->local_window) {
2480 logit("channel %d: rcvd too much extended_data %d, win %d",
2481 c->self, data_len, c->local_window);
2482 free(data);
2483 return;
2484 }
2485 debug2("channel %d: rcvd ext data %d", c->self, data_len);
2486 c->local_window -= data_len;
2487 buffer_append(&c->extended, data, data_len);
2488 free(data);
2489 }
2490
2491 /* ARGSUSED */
2492 void
2493 channel_input_ieof(int type, u_int32_t seq, void *ctxt)
2494 {
2495 int id;
2496 Channel *c;
2497
2498 id = packet_get_int();
2499 packet_check_eom();
2500 c = channel_lookup(id);
2501 if (c == NULL)
2502 packet_disconnect("Received ieof for nonexistent channel %d.", id);
2503 chan_rcvd_ieof(c);
2504
2505 /* XXX force input close */
2506 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) {
2507 debug("channel %d: FORCE input drain", c->self);
2508 c->istate = CHAN_INPUT_WAIT_DRAIN;
2509 if (buffer_len(&c->input) == 0)
2510 chan_ibuf_empty(c);
2511 }
2512
2513 }
2514
2515 /* ARGSUSED */
2516 void
2517 channel_input_close(int type, u_int32_t seq, void *ctxt)
2518 {
2519 int id;
2520 Channel *c;
2521
2522 id = packet_get_int();
2523 packet_check_eom();
2524 c = channel_lookup(id);
2525 if (c == NULL)
2526 packet_disconnect("Received close for nonexistent channel %d.", id);
2527
2528 /*
2529 * Send a confirmation that we have closed the channel and no more
2530 * data is coming for it.
2531 */
2532 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
2533 packet_put_int(c->remote_id);
2534 packet_send();
2535
2536 /*
2537 * If the channel is in closed state, we have sent a close request,
2538 * and the other side will eventually respond with a confirmation.
2539 * Thus, we cannot free the channel here, because then there would be
2540 * no-one to receive the confirmation. The channel gets freed when
2541 * the confirmation arrives.
2542 */
2543 if (c->type != SSH_CHANNEL_CLOSED) {
2544 /*
2545 * Not a closed channel - mark it as draining, which will
2546 * cause it to be freed later.
2547 */
2548 buffer_clear(&c->input);
2549 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
2550 }
2551 }
2552
2553 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
2554 /* ARGSUSED */
2555 void
2556 channel_input_oclose(int type, u_int32_t seq, void *ctxt)
2557 {
2558 int id = packet_get_int();
2559 Channel *c = channel_lookup(id);
2560
2561 packet_check_eom();
2562 if (c == NULL)
2563 packet_disconnect("Received oclose for nonexistent channel %d.", id);
2564 chan_rcvd_oclose(c);
2565 }
2566
2567 /* ARGSUSED */
2568 void
2569 channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt)
2570 {
2571 int id = packet_get_int();
2572 Channel *c = channel_lookup(id);
2573
2574 packet_check_eom();
2575 if (c == NULL)
2576 packet_disconnect("Received close confirmation for "
2577 "out-of-range channel %d.", id);
2578 if (c->type != SSH_CHANNEL_CLOSED && c->type != SSH_CHANNEL_ABANDONED)
2579 packet_disconnect("Received close confirmation for "
2580 "non-closed channel %d (type %d).", id, c->type);
2581 channel_free(c);
2582 }
2583
2584 /* ARGSUSED */
2585 void
2586 channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt)
2587 {
2588 int id, remote_id;
2589 Channel *c;
2590
2591 id = packet_get_int();
2592 c = channel_lookup(id);
2593
2594 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2595 packet_disconnect("Received open confirmation for "
2596 "non-opening channel %d.", id);
2597 remote_id = packet_get_int();
2598 /* Record the remote channel number and mark that the channel is now open. */
2599 c->remote_id = remote_id;
2600 c->type = SSH_CHANNEL_OPEN;
2601
2602 if (compat20) {
2603 c->remote_window = packet_get_int();
2604 c->remote_maxpacket = packet_get_int();
2605 if (c->open_confirm) {
2606 debug2("callback start");
2607 c->open_confirm(c->self, 1, c->open_confirm_ctx);
2608 debug2("callback done");
2609 }
2610 debug2("channel %d: open confirm rwindow %u rmax %u", c->self,
2611 c->remote_window, c->remote_maxpacket);
2612 }
2613 packet_check_eom();
2614 }
2615
2616 static char *
2617 reason2txt(int reason)
2618 {
2619 switch (reason) {
2620 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
2621 return "administratively prohibited";
2622 case SSH2_OPEN_CONNECT_FAILED:
2623 return "connect failed";
2624 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
2625 return "unknown channel type";
2626 case SSH2_OPEN_RESOURCE_SHORTAGE:
2627 return "resource shortage";
2628 }
2629 return "unknown reason";
2630 }
2631
2632 /* ARGSUSED */
2633 void
2634 channel_input_open_failure(int type, u_int32_t seq, void *ctxt)
2635 {
2636 int id, reason;
2637 char *msg = NULL, *lang = NULL;
2638 Channel *c;
2639
2640 id = packet_get_int();
2641 c = channel_lookup(id);
2642
2643 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2644 packet_disconnect("Received open failure for "
2645 "non-opening channel %d.", id);
2646 if (compat20) {
2647 reason = packet_get_int();
2648 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
2649 msg = packet_get_string(NULL);
2650 lang = packet_get_string(NULL);
2651 }
2652 logit("channel %d: open failed: %s%s%s", id,
2653 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
2654 free(msg);
2655 free(lang);
2656 if (c->open_confirm) {
2657 debug2("callback start");
2658 c->open_confirm(c->self, 0, c->open_confirm_ctx);
2659 debug2("callback done");
2660 }
2661 }
2662 packet_check_eom();
2663 /* Schedule the channel for cleanup/deletion. */
2664 chan_mark_dead(c);
2665 }
2666
2667 /* ARGSUSED */
2668 void
2669 channel_input_window_adjust(int type, u_int32_t seq, void *ctxt)
2670 {
2671 Channel *c;
2672 int id;
2673 u_int adjust;
2674
2675 if (!compat20)
2676 return;
2677
2678 /* Get the channel number and verify it. */
2679 id = packet_get_int();
2680 c = channel_lookup(id);
2681
2682 if (c == NULL) {
2683 logit("Received window adjust for non-open channel %d.", id);
2684 return;
2685 }
2686 adjust = packet_get_int();
2687 packet_check_eom();
2688 debug2("channel %d: rcvd adjust %u", id, adjust);
2689 c->remote_window += adjust;
2690 }
2691
2692 /* ARGSUSED */
2693 void
2694 channel_input_port_open(int type, u_int32_t seq, void *ctxt)
2695 {
2696 Channel *c = NULL;
2697 u_short host_port;
2698 char *host, *originator_string;
2699 int remote_id;
2700
2701 remote_id = packet_get_int();
2702 host = packet_get_string(NULL);
2703 host_port = packet_get_int();
2704
2705 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2706 originator_string = packet_get_string(NULL);
2707 } else {
2708 originator_string = xstrdup("unknown (remote did not supply name)");
2709 }
2710 packet_check_eom();
2711 c = channel_connect_to_port(host, host_port,
2712 "connected socket", originator_string);
2713 free(originator_string);
2714 free(host);
2715 if (c == NULL) {
2716 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2717 packet_put_int(remote_id);
2718 packet_send();
2719 } else
2720 c->remote_id = remote_id;
2721 }
2722
2723 /* ARGSUSED */
2724 void
2725 channel_input_status_confirm(int type, u_int32_t seq, void *ctxt)
2726 {
2727 Channel *c;
2728 struct channel_confirm *cc;
2729 int id;
2730
2731 /* Reset keepalive timeout */
2732 packet_set_alive_timeouts(0);
2733
2734 id = packet_get_int();
2735 packet_check_eom();
2736
2737 debug2("channel_input_status_confirm: type %d id %d", type, id);
2738
2739 if ((c = channel_lookup(id)) == NULL) {
2740 logit("channel_input_status_confirm: %d: unknown", id);
2741 return;
2742 }
2743 ;
2744 if ((cc = TAILQ_FIRST(&c->status_confirms)) == NULL)
2745 return;
2746 cc->cb(type, c, cc->ctx);
2747 TAILQ_REMOVE(&c->status_confirms, cc, entry);
2748 explicit_bzero(cc, sizeof(*cc));
2749 free(cc);
2750 }
2751
2752 /* -- tcp forwarding */
2753
2754 void
2755 channel_set_af(int af)
2756 {
2757 IPv4or6 = af;
2758 }
2759
2760
2761 void
2762 channel_set_hpn(int external_hpn_disabled, int external_hpn_buffer_size)
2763 {
2764 hpn_disabled = external_hpn_disabled;
2765 hpn_buffer_size = external_hpn_buffer_size;
2766 debug("HPN Disabled: %d, HPN Buffer Size: %d", hpn_disabled, hpn_buffer_size);
2767 }
2768 /*
2769 * Determine whether or not a port forward listens to loopback, the
2770 * specified address or wildcard. On the client, a specified bind
2771 * address will always override gateway_ports. On the server, a
2772 * gateway_ports of 1 (``yes'') will override the client's specification
2773 * and force a wildcard bind, whereas a value of 2 (``clientspecified'')
2774 * will bind to whatever address the client asked for.
2775 *
2776 * Special-case listen_addrs are:
2777 *
2778 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR
2779 * "" (empty string), "*" -> wildcard v4/v6
2780 * "localhost" -> loopback v4/v6
2781 * "127.0.0.1" / "::1" -> accepted even if gateway_ports isn't set
2782 */
2783 static const char *
2784 channel_fwd_bind_addr(const char *listen_addr, int *wildcardp,
2785 int is_client, struct ForwardOptions *fwd_opts)
2786 {
2787 const char *addr = NULL;
2788 int wildcard = 0;
2789
2790 if (listen_addr == NULL) {
2791 /* No address specified: default to gateway_ports setting */
2792 if (fwd_opts->gateway_ports)
2793 wildcard = 1;
2794 } else if (fwd_opts->gateway_ports || is_client) {
2795 if (((datafellows & SSH_OLD_FORWARD_ADDR) &&
2796 strcmp(listen_addr, "0.0.0.0") == 0 && is_client == 0) ||
2797 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 ||
2798 (!is_client && fwd_opts->gateway_ports == 1)) {
2799 wildcard = 1;
2800 /*
2801 * Notify client if they requested a specific listen
2802 * address and it was overridden.
2803 */
2804 if (*listen_addr != '\0' &&
2805 strcmp(listen_addr, "0.0.0.0") != 0 &&
2806 strcmp(listen_addr, "*") != 0) {
2807 packet_send_debug("Forwarding listen address "
2808 "\"%s\" overridden by server "
2809 "GatewayPorts", listen_addr);
2810 }
2811 } else if (strcmp(listen_addr, "localhost") != 0 ||
2812 strcmp(listen_addr, "127.0.0.1") == 0 ||
2813 strcmp(listen_addr, "::1") == 0) {
2814 /* Accept localhost address when GatewayPorts=yes */
2815 addr = listen_addr;
2816 }
2817 } else if (strcmp(listen_addr, "127.0.0.1") == 0 ||
2818 strcmp(listen_addr, "::1") == 0) {
2819 /*
2820 * If a specific IPv4/IPv6 localhost address has been
2821 * requested then accept it even if gateway_ports is in
2822 * effect. This allows the client to prefer IPv4 or IPv6.
2823 */
2824 addr = listen_addr;
2825 }
2826 if (wildcardp != NULL)
2827 *wildcardp = wildcard;
2828 return addr;
2829 }
2830
2831 static int
2832 channel_setup_fwd_listener_tcpip(int type, struct Forward *fwd,
2833 int *allocated_listen_port, struct ForwardOptions *fwd_opts)
2834 {
2835 Channel *c;
2836 int sock, r, success = 0, wildcard = 0, is_client;
2837 struct addrinfo hints, *ai, *aitop;
2838 const char *host, *addr;
2839 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2840 in_port_t *lport_p;
2841
2842 host = (type == SSH_CHANNEL_RPORT_LISTENER) ?
2843 fwd->listen_host : fwd->connect_host;
2844 is_client = (type == SSH_CHANNEL_PORT_LISTENER);
2845
2846 if (host == NULL) {
2847 error("No forward host name.");
2848 return 0;
2849 }
2850 if (strlen(host) >= NI_MAXHOST) {
2851 error("Forward host name too long.");
2852 return 0;
2853 }
2854
2855 /* Determine the bind address, cf. channel_fwd_bind_addr() comment */
2856 addr = channel_fwd_bind_addr(fwd->listen_host, &wildcard,
2857 is_client, fwd_opts);
2858 debug3("%s: type %d wildcard %d addr %s", __func__,
2859 type, wildcard, (addr == NULL) ? "NULL" : addr);
2860
2861 /*
2862 * getaddrinfo returns a loopback address if the hostname is
2863 * set to NULL and hints.ai_flags is not AI_PASSIVE
2864 */
2865 memset(&hints, 0, sizeof(hints));
2866 hints.ai_family = IPv4or6;
2867 hints.ai_flags = wildcard ? AI_PASSIVE : 0;
2868 hints.ai_socktype = SOCK_STREAM;
2869 snprintf(strport, sizeof strport, "%d", fwd->listen_port);
2870 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) {
2871 if (addr == NULL) {
2872 /* This really shouldn't happen */
2873 packet_disconnect("getaddrinfo: fatal error: %s",
2874 ssh_gai_strerror(r));
2875 } else {
2876 error("%s: getaddrinfo(%.64s): %s", __func__, addr,
2877 ssh_gai_strerror(r));
2878 }
2879 return 0;
2880 }
2881 if (allocated_listen_port != NULL)
2882 *allocated_listen_port = 0;
2883 for (ai = aitop; ai; ai = ai->ai_next) {
2884 switch (ai->ai_family) {
2885 case AF_INET:
2886 lport_p = &((struct sockaddr_in *)ai->ai_addr)->
2887 sin_port;
2888 break;
2889 case AF_INET6:
2890 lport_p = &((struct sockaddr_in6 *)ai->ai_addr)->
2891 sin6_port;
2892 break;
2893 default:
2894 continue;
2895 }
2896 /*
2897 * If allocating a port for -R forwards, then use the
2898 * same port for all address families.
2899 */
2900 if (type == SSH_CHANNEL_RPORT_LISTENER && fwd->listen_port == 0 &&
2901 allocated_listen_port != NULL && *allocated_listen_port > 0)
2902 *lport_p = htons(*allocated_listen_port);
2903
2904 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2905 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2906 error("%s: getnameinfo failed", __func__);
2907 continue;
2908 }
2909 /* Create a port to listen for the host. */
2910 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2911 if (sock < 0) {
2912 /* this is no error since kernel may not support ipv6 */
2913 verbose("socket: %.100s", strerror(errno));
2914 continue;
2915 }
2916
2917 channel_set_reuseaddr(sock);
2918 if (ai->ai_family == AF_INET6)
2919 sock_set_v6only(sock);
2920
2921 debug("Local forwarding listening on %s port %s.",
2922 ntop, strport);
2923
2924 /* Bind the socket to the address. */
2925 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2926 /* address can be in use ipv6 address is already bound */
2927 if (!ai->ai_next)
2928 error("bind: %.100s", strerror(errno));
2929 else
2930 verbose("bind: %.100s", strerror(errno));
2931
2932 close(sock);
2933 continue;
2934 }
2935 /* Start listening for connections on the socket. */
2936 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2937 error("listen: %.100s", strerror(errno));
2938 close(sock);
2939 continue;
2940 }
2941
2942 /*
2943 * fwd->listen_port == 0 requests a dynamically allocated port -
2944 * record what we got.
2945 */
2946 if (type == SSH_CHANNEL_RPORT_LISTENER && fwd->listen_port == 0 &&
2947 allocated_listen_port != NULL &&
2948 *allocated_listen_port == 0) {
2949 *allocated_listen_port = get_sock_port(sock, 1);
2950 debug("Allocated listen port %d",
2951 *allocated_listen_port);
2952 }
2953
2954 /* Allocate a channel number for the socket. */
2955 /* explicitly test for hpn disabled option. if true use smaller window size */
2956 if (hpn_disabled)
2957 c = channel_new("port listener", type, sock, sock, -1,
2958 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2959 0, "port listener", 1);
2960 else
2961 c = channel_new("port listener", type, sock, sock, -1,
2962 hpn_buffer_size, CHAN_TCP_PACKET_DEFAULT,
2963 0, "port listener", 1);
2964 c->path = xstrdup(host);
2965 c->host_port = fwd->connect_port;
2966 c->listening_addr = addr == NULL ? NULL : xstrdup(addr);
2967 if (fwd->listen_port == 0 && allocated_listen_port != NULL &&
2968 !(datafellows & SSH_BUG_DYNAMIC_RPORT))
2969 c->listening_port = *allocated_listen_port;
2970 else
2971 c->listening_port = fwd->listen_port;
2972 success = 1;
2973 }
2974 if (success == 0)
2975 error("%s: cannot listen to port: %d", __func__,
2976 fwd->listen_port);
2977 freeaddrinfo(aitop);
2978 return success;
2979 }
2980
2981 static int
2982 channel_setup_fwd_listener_streamlocal(int type, struct Forward *fwd,
2983 struct ForwardOptions *fwd_opts)
2984 {
2985 struct sockaddr_un sunaddr;
2986 const char *path;
2987 Channel *c;
2988 int port, sock;
2989 mode_t omask;
2990
2991 switch (type) {
2992 case SSH_CHANNEL_UNIX_LISTENER:
2993 if (fwd->connect_path != NULL) {
2994 if (strlen(fwd->connect_path) > sizeof(sunaddr.sun_path)) {
2995 error("Local connecting path too long: %s",
2996 fwd->connect_path);
2997 return 0;
2998 }
2999 path = fwd->connect_path;
3000 port = PORT_STREAMLOCAL;
3001 } else {
3002 if (fwd->connect_host == NULL) {
3003 error("No forward host name.");
3004 return 0;
3005 }
3006 if (strlen(fwd->connect_host) >= NI_MAXHOST) {
3007 error("Forward host name too long.");
3008 return 0;
3009 }
3010 path = fwd->connect_host;
3011 port = fwd->connect_port;
3012 }
3013 break;
3014 case SSH_CHANNEL_RUNIX_LISTENER:
3015 path = fwd->listen_path;
3016 port = PORT_STREAMLOCAL;
3017 break;
3018 default:
3019 error("%s: unexpected channel type %d", __func__, type);
3020 return 0;
3021 }
3022
3023 if (fwd->listen_path == NULL) {
3024 error("No forward path name.");
3025 return 0;
3026 }
3027 if (strlen(fwd->listen_path) > sizeof(sunaddr.sun_path)) {
3028 error("Local listening path too long: %s", fwd->listen_path);
3029 return 0;
3030 }
3031
3032 debug3("%s: type %d path %s", __func__, type, fwd->listen_path);
3033
3034 /* Start a Unix domain listener. */
3035 omask = umask(fwd_opts->streamlocal_bind_mask);
3036 sock = unix_listener(fwd->listen_path, SSH_LISTEN_BACKLOG,
3037 fwd_opts->streamlocal_bind_unlink);
3038 umask(omask);
3039 if (sock < 0)
3040 return 0;
3041
3042 debug("Local forwarding listening on path %s.", fwd->listen_path);
3043
3044 /* Allocate a channel number for the socket. */
3045 c = channel_new("unix listener", type, sock, sock, -1,
3046 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
3047 0, "unix listener", 1);
3048 c->path = xstrdup(path);
3049 c->host_port = port;
3050 c->listening_port = PORT_STREAMLOCAL;
3051 c->listening_addr = xstrdup(fwd->listen_path);
3052 return 1;
3053 }
3054
3055 static int
3056 channel_cancel_rport_listener_tcpip(const char *host, u_short port)
3057 {
3058 u_int i;
3059 int found = 0;
3060
3061 for (i = 0; i < channels_alloc; i++) {
3062 Channel *c = channels[i];
3063 if (c == NULL || c->type != SSH_CHANNEL_RPORT_LISTENER)
3064 continue;
3065 if (strcmp(c->path, host) == 0 && c->listening_port == port) {
3066 debug2("%s: close channel %d", __func__, i);
3067 channel_free(c);
3068 found = 1;
3069 }
3070 }
3071
3072 return (found);
3073 }
3074
3075 static int
3076 channel_cancel_rport_listener_streamlocal(const char *path)
3077 {
3078 u_int i;
3079 int found = 0;
3080
3081 for (i = 0; i < channels_alloc; i++) {
3082 Channel *c = channels[i];
3083 if (c == NULL || c->type != SSH_CHANNEL_RUNIX_LISTENER)
3084 continue;
3085 if (c->path == NULL)
3086 continue;
3087 if (strcmp(c->path, path) == 0) {
3088 debug2("%s: close channel %d", __func__, i);
3089 channel_free(c);
3090 found = 1;
3091 }
3092 }
3093
3094 return (found);
3095 }
3096
3097 int
3098 channel_cancel_rport_listener(struct Forward *fwd)
3099 {
3100 if (fwd->listen_path != NULL)
3101 return channel_cancel_rport_listener_streamlocal(fwd->listen_path);
3102 else
3103 return channel_cancel_rport_listener_tcpip(fwd->listen_host, fwd->listen_port);
3104 }
3105
3106 static int
3107 channel_cancel_lport_listener_tcpip(const char *lhost, u_short lport,
3108 int cport, struct ForwardOptions *fwd_opts)
3109 {
3110 u_int i;
3111 int found = 0;
3112 const char *addr = channel_fwd_bind_addr(lhost, NULL, 1, fwd_opts);
3113
3114 for (i = 0; i < channels_alloc; i++) {
3115 Channel *c = channels[i];
3116 if (c == NULL || c->type != SSH_CHANNEL_PORT_LISTENER)
3117 continue;
3118 if (c->listening_port != lport)
3119 continue;
3120 if (cport == CHANNEL_CANCEL_PORT_STATIC) {
3121 /* skip dynamic forwardings */
3122 if (c->host_port == 0)
3123 continue;
3124 } else {
3125 if (c->host_port != cport)
3126 continue;
3127 }
3128 if ((c->listening_addr == NULL && addr != NULL) ||
3129 (c->listening_addr != NULL && addr == NULL))
3130 continue;
3131 if (addr == NULL || strcmp(c->listening_addr, addr) == 0) {
3132 debug2("%s: close channel %d", __func__, i);
3133 channel_free(c);
3134 found = 1;
3135 }
3136 }
3137
3138 return (found);
3139 }
3140
3141 static int
3142 channel_cancel_lport_listener_streamlocal(const char *path)
3143 {
3144 u_int i;
3145 int found = 0;
3146
3147 if (path == NULL) {
3148 error("%s: no path specified.", __func__);
3149 return 0;
3150 }
3151
3152 for (i = 0; i < channels_alloc; i++) {
3153 Channel *c = channels[i];
3154 if (c == NULL || c->type != SSH_CHANNEL_UNIX_LISTENER)
3155 continue;
3156 if (c->listening_addr == NULL)
3157 continue;
3158 if (strcmp(c->listening_addr, path) == 0) {
3159 debug2("%s: close channel %d", __func__, i);
3160 channel_free(c);
3161 found = 1;
3162 }
3163 }
3164
3165 return (found);
3166 }
3167
3168 int
3169 channel_cancel_lport_listener(struct Forward *fwd, int cport, struct ForwardOptions *fwd_opts)
3170 {
3171 if (fwd->listen_path != NULL)
3172 return channel_cancel_lport_listener_streamlocal(fwd->listen_path);
3173 else
3174 return channel_cancel_lport_listener_tcpip(fwd->listen_host, fwd->listen_port, cport, fwd_opts);
3175 }
3176
3177 /* protocol local port fwd, used by ssh (and sshd in v1) */
3178 int
3179 channel_setup_local_fwd_listener(struct Forward *fwd, struct ForwardOptions *fwd_opts)
3180 {
3181 if (fwd->listen_path != NULL) {
3182 return channel_setup_fwd_listener_streamlocal(
3183 SSH_CHANNEL_UNIX_LISTENER, fwd, fwd_opts);
3184 } else {
3185 return channel_setup_fwd_listener_tcpip(SSH_CHANNEL_PORT_LISTENER,
3186 fwd, NULL, fwd_opts);
3187 }
3188 }
3189
3190 /* protocol v2 remote port fwd, used by sshd */
3191 int
3192 channel_setup_remote_fwd_listener(struct Forward *fwd,
3193 int *allocated_listen_port, struct ForwardOptions *fwd_opts)
3194 {
3195 if (fwd->listen_path != NULL) {
3196 return channel_setup_fwd_listener_streamlocal(
3197 SSH_CHANNEL_RUNIX_LISTENER, fwd, fwd_opts);
3198 } else {
3199 return channel_setup_fwd_listener_tcpip(
3200 SSH_CHANNEL_RPORT_LISTENER, fwd, allocated_listen_port,
3201 fwd_opts);
3202 }
3203 }
3204
3205 /*
3206 * Translate the requested rfwd listen host to something usable for
3207 * this server.
3208 */
3209 static const char *
3210 channel_rfwd_bind_host(const char *listen_host)
3211 {
3212 if (listen_host == NULL) {
3213 if (datafellows & SSH_BUG_RFWD_ADDR)
3214 return "127.0.0.1";
3215 else
3216 return "localhost";
3217 } else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0) {
3218 if (datafellows & SSH_BUG_RFWD_ADDR)
3219 return "0.0.0.0";
3220 else
3221 return "";
3222 } else
3223 return listen_host;
3224 }
3225
3226 /*
3227 * Initiate forwarding of connections to port "port" on remote host through
3228 * the secure channel to host:port from local side.
3229 * Returns handle (index) for updating the dynamic listen port with
3230 * channel_update_permitted_opens().
3231 */
3232 int
3233 channel_request_remote_forwarding(struct Forward *fwd)
3234 {
3235 int type, success = 0, idx = -1;
3236
3237 /* Send the forward request to the remote side. */
3238 if (compat20) {
3239 packet_start(SSH2_MSG_GLOBAL_REQUEST);
3240 if (fwd->listen_path != NULL) {
3241 packet_put_cstring("streamlocal-forward@openssh.com");
3242 packet_put_char(1); /* boolean: want reply */
3243 packet_put_cstring(fwd->listen_path);
3244 } else {
3245 packet_put_cstring("tcpip-forward");
3246 packet_put_char(1); /* boolean: want reply */
3247 packet_put_cstring(channel_rfwd_bind_host(fwd->listen_host));
3248 packet_put_int(fwd->listen_port);
3249 }
3250 packet_send();
3251 packet_write_wait();
3252 /* Assume that server accepts the request */
3253 success = 1;
3254 } else if (fwd->listen_path == NULL) {
3255 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
3256 packet_put_int(fwd->listen_port);
3257 packet_put_cstring(fwd->connect_host);
3258 packet_put_int(fwd->connect_port);
3259 packet_send();
3260 packet_write_wait();
3261
3262 /* Wait for response from the remote side. */
3263 type = packet_read();
3264 switch (type) {
3265 case SSH_SMSG_SUCCESS:
3266 success = 1;
3267 break;
3268 case SSH_SMSG_FAILURE:
3269 break;
3270 default:
3271 /* Unknown packet */
3272 packet_disconnect("Protocol error for port forward request:"
3273 "received packet type %d.", type);
3274 }
3275 } else {
3276 logit("Warning: Server does not support remote stream local forwarding.");
3277 }
3278 if (success) {
3279 /* Record that connection to this host/port is permitted. */
3280 permitted_opens = xrealloc(permitted_opens,
3281 num_permitted_opens + 1, sizeof(*permitted_opens));
3282 idx = num_permitted_opens++;
3283 if (fwd->connect_path != NULL) {
3284 permitted_opens[idx].host_to_connect =
3285 xstrdup(fwd->connect_path);
3286 permitted_opens[idx].port_to_connect =
3287 PORT_STREAMLOCAL;
3288 } else {
3289 permitted_opens[idx].host_to_connect =
3290 xstrdup(fwd->connect_host);
3291 permitted_opens[idx].port_to_connect =
3292 fwd->connect_port;
3293 }
3294 if (fwd->listen_path != NULL) {
3295 permitted_opens[idx].listen_host = NULL;
3296 permitted_opens[idx].listen_path =
3297 xstrdup(fwd->listen_path);
3298 permitted_opens[idx].listen_port = PORT_STREAMLOCAL;
3299 } else {
3300 permitted_opens[idx].listen_host =
3301 fwd->listen_host ? xstrdup(fwd->listen_host) : NULL;
3302 permitted_opens[idx].listen_path = NULL;
3303 permitted_opens[idx].listen_port = fwd->listen_port;
3304 }
3305 }
3306 return (idx);
3307 }
3308
3309 static int
3310 open_match(ForwardPermission *allowed_open, const char *requestedhost,
3311 int requestedport)
3312 {
3313 if (allowed_open->host_to_connect == NULL)
3314 return 0;
3315 if (allowed_open->port_to_connect != FWD_PERMIT_ANY_PORT &&
3316 allowed_open->port_to_connect != requestedport)
3317 return 0;
3318 if (strcmp(allowed_open->host_to_connect, requestedhost) != 0)
3319 return 0;
3320 return 1;
3321 }
3322
3323 /*
3324 * Note that in the listen host/port case
3325 * we don't support FWD_PERMIT_ANY_PORT and
3326 * need to translate between the configured-host (listen_host)
3327 * and what we've sent to the remote server (channel_rfwd_bind_host)
3328 */
3329 static int
3330 open_listen_match_tcpip(ForwardPermission *allowed_open,
3331 const char *requestedhost, u_short requestedport, int translate)
3332 {
3333 const char *allowed_host;
3334
3335 if (allowed_open->host_to_connect == NULL)
3336 return 0;
3337 if (allowed_open->listen_port != requestedport)
3338 return 0;
3339 if (!translate && allowed_open->listen_host == NULL &&
3340 requestedhost == NULL)
3341 return 1;
3342 allowed_host = translate ?
3343 channel_rfwd_bind_host(allowed_open->listen_host) :
3344 allowed_open->listen_host;
3345 if (allowed_host == NULL ||
3346 strcmp(allowed_host, requestedhost) != 0)
3347 return 0;
3348 return 1;
3349 }
3350
3351 static int
3352 open_listen_match_streamlocal(ForwardPermission *allowed_open,
3353 const char *requestedpath)
3354 {
3355 if (allowed_open->host_to_connect == NULL)
3356 return 0;
3357 if (allowed_open->listen_port != PORT_STREAMLOCAL)
3358 return 0;
3359 if (allowed_open->listen_path == NULL ||
3360 strcmp(allowed_open->listen_path, requestedpath) != 0)
3361 return 0;
3362 return 1;
3363 }
3364
3365 /*
3366 * Request cancellation of remote forwarding of connection host:port from
3367 * local side.
3368 */
3369 static int
3370 channel_request_rforward_cancel_tcpip(const char *host, u_short port)
3371 {
3372 int i;
3373
3374 if (!compat20)
3375 return -1;
3376
3377 for (i = 0; i < num_permitted_opens; i++) {
3378 if (open_listen_match_tcpip(&permitted_opens[i], host, port, 0))
3379 break;
3380 }
3381 if (i >= num_permitted_opens) {
3382 debug("%s: requested forward not found", __func__);
3383 return -1;
3384 }
3385 packet_start(SSH2_MSG_GLOBAL_REQUEST);
3386 packet_put_cstring("cancel-tcpip-forward");
3387 packet_put_char(0);
3388 packet_put_cstring(channel_rfwd_bind_host(host));
3389 packet_put_int(port);
3390 packet_send();
3391
3392 permitted_opens[i].listen_port = 0;
3393 permitted_opens[i].port_to_connect = 0;
3394 free(permitted_opens[i].host_to_connect);
3395 permitted_opens[i].host_to_connect = NULL;
3396 free(permitted_opens[i].listen_host);
3397 permitted_opens[i].listen_host = NULL;
3398 permitted_opens[i].listen_path = NULL;
3399
3400 return 0;
3401 }
3402
3403 /*
3404 * Request cancellation of remote forwarding of Unix domain socket
3405 * path from local side.
3406 */
3407 static int
3408 channel_request_rforward_cancel_streamlocal(const char *path)
3409 {
3410 int i;
3411
3412 if (!compat20)
3413 return -1;
3414
3415 for (i = 0; i < num_permitted_opens; i++) {
3416 if (open_listen_match_streamlocal(&permitted_opens[i], path))
3417 break;
3418 }
3419 if (i >= num_permitted_opens) {
3420 debug("%s: requested forward not found", __func__);
3421 return -1;
3422 }
3423 packet_start(SSH2_MSG_GLOBAL_REQUEST);
3424 packet_put_cstring("cancel-streamlocal-forward@openssh.com");
3425 packet_put_char(0);
3426 packet_put_cstring(path);
3427 packet_send();
3428
3429 permitted_opens[i].listen_port = 0;
3430 permitted_opens[i].port_to_connect = 0;
3431 free(permitted_opens[i].host_to_connect);
3432 permitted_opens[i].host_to_connect = NULL;
3433 permitted_opens[i].listen_host = NULL;
3434 free(permitted_opens[i].listen_path);
3435 permitted_opens[i].listen_path = NULL;
3436
3437 return 0;
3438 }
3439
3440 /*
3441 * Request cancellation of remote forwarding of a connection from local side.
3442 */
3443 int
3444 channel_request_rforward_cancel(struct Forward *fwd)
3445 {
3446 if (fwd->listen_path != NULL) {
3447 return (channel_request_rforward_cancel_streamlocal(
3448 fwd->listen_path));
3449 } else {
3450 return (channel_request_rforward_cancel_tcpip(fwd->listen_host,
3451 fwd->listen_port ? fwd->listen_port : fwd->allocated_port));
3452 }
3453 }
3454
3455 /*
3456 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
3457 * listening for the port, and sends back a success reply (or disconnect
3458 * message if there was an error).
3459 */
3460 int
3461 channel_input_port_forward_request(int is_root, struct ForwardOptions *fwd_opts)
3462 {
3463 int success = 0;
3464 struct Forward fwd;
3465
3466 /* Get arguments from the packet. */
3467 memset(&fwd, 0, sizeof(fwd));
3468 fwd.listen_port = packet_get_int();
3469 fwd.connect_host = packet_get_string(NULL);
3470 fwd.connect_port = packet_get_int();
3471
3472 #ifndef HAVE_CYGWIN
3473 /*
3474 * Check that an unprivileged user is not trying to forward a
3475 * privileged port.
3476 */
3477 if (fwd.listen_port < IPPORT_RESERVED && !is_root)
3478 packet_disconnect(
3479 "Requested forwarding of port %d but user is not root.",
3480 fwd.listen_port);
3481 if (fwd.connect_port == 0)
3482 packet_disconnect("Dynamic forwarding denied.");
3483 #endif
3484
3485 /* Initiate forwarding */
3486 success = channel_setup_local_fwd_listener(&fwd, fwd_opts);
3487
3488 /* Free the argument string. */
3489 free(fwd.connect_host);
3490
3491 return (success ? 0 : -1);
3492 }
3493
3494 /*
3495 * Permits opening to any host/port if permitted_opens[] is empty. This is
3496 * usually called by the server, because the user could connect to any port
3497 * anyway, and the server has no way to know but to trust the client anyway.
3498 */
3499 void
3500 channel_permit_all_opens(void)
3501 {
3502 if (num_permitted_opens == 0)
3503 all_opens_permitted = 1;
3504 }
3505
3506 void
3507 channel_add_permitted_opens(char *host, int port)
3508 {
3509 debug("allow port forwarding to host %s port %d", host, port);
3510
3511 permitted_opens = xrealloc(permitted_opens,
3512 num_permitted_opens + 1, sizeof(*permitted_opens));
3513 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
3514 permitted_opens[num_permitted_opens].port_to_connect = port;
3515 permitted_opens[num_permitted_opens].listen_host = NULL;
3516 permitted_opens[num_permitted_opens].listen_path = NULL;
3517 permitted_opens[num_permitted_opens].listen_port = 0;
3518 num_permitted_opens++;
3519
3520 all_opens_permitted = 0;
3521 }
3522
3523 /*
3524 * Update the listen port for a dynamic remote forward, after
3525 * the actual 'newport' has been allocated. If 'newport' < 0 is
3526 * passed then they entry will be invalidated.
3527 */
3528 void
3529 channel_update_permitted_opens(int idx, int newport)
3530 {
3531 if (idx < 0 || idx >= num_permitted_opens) {
3532 debug("channel_update_permitted_opens: index out of range:"
3533 " %d num_permitted_opens %d", idx, num_permitted_opens);
3534 return;
3535 }
3536 debug("%s allowed port %d for forwarding to host %s port %d",
3537 newport > 0 ? "Updating" : "Removing",
3538 newport,
3539 permitted_opens[idx].host_to_connect,
3540 permitted_opens[idx].port_to_connect);
3541 if (newport >= 0) {
3542 permitted_opens[idx].listen_port =
3543 (datafellows & SSH_BUG_DYNAMIC_RPORT) ? 0 : newport;
3544 } else {
3545 permitted_opens[idx].listen_port = 0;
3546 permitted_opens[idx].port_to_connect = 0;
3547 free(permitted_opens[idx].host_to_connect);
3548 permitted_opens[idx].host_to_connect = NULL;
3549 free(permitted_opens[idx].listen_host);
3550 permitted_opens[idx].listen_host = NULL;
3551 free(permitted_opens[idx].listen_path);
3552 permitted_opens[idx].listen_path = NULL;
3553 }
3554 }
3555
3556 int
3557 channel_add_adm_permitted_opens(char *host, int port)
3558 {
3559 debug("config allows port forwarding to host %s port %d", host, port);
3560
3561 permitted_adm_opens = xrealloc(permitted_adm_opens,
3562 num_adm_permitted_opens + 1, sizeof(*permitted_adm_opens));
3563 permitted_adm_opens[num_adm_permitted_opens].host_to_connect
3564 = xstrdup(host);
3565 permitted_adm_opens[num_adm_permitted_opens].port_to_connect = port;
3566 permitted_adm_opens[num_adm_permitted_opens].listen_host = NULL;
3567 permitted_adm_opens[num_adm_permitted_opens].listen_path = NULL;
3568 permitted_adm_opens[num_adm_permitted_opens].listen_port = 0;
3569 return ++num_adm_permitted_opens;
3570 }
3571
3572 void
3573 channel_disable_adm_local_opens(void)
3574 {
3575 channel_clear_adm_permitted_opens();
3576 permitted_adm_opens = xmalloc(sizeof(*permitted_adm_opens));
3577 permitted_adm_opens[num_adm_permitted_opens].host_to_connect = NULL;
3578 num_adm_permitted_opens = 1;
3579 }
3580
3581 void
3582 channel_clear_permitted_opens(void)
3583 {
3584 int i;
3585
3586 for (i = 0; i < num_permitted_opens; i++) {
3587 free(permitted_opens[i].host_to_connect);
3588 free(permitted_opens[i].listen_host);
3589 free(permitted_opens[i].listen_path);
3590 }
3591 free(permitted_opens);
3592 permitted_opens = NULL;
3593 num_permitted_opens = 0;
3594 }
3595
3596 void
3597 channel_clear_adm_permitted_opens(void)
3598 {
3599 int i;
3600
3601 for (i = 0; i < num_adm_permitted_opens; i++) {
3602 free(permitted_adm_opens[i].host_to_connect);
3603 free(permitted_adm_opens[i].listen_host);
3604 free(permitted_adm_opens[i].listen_path);
3605 }
3606 free(permitted_adm_opens);
3607 permitted_adm_opens = NULL;
3608 num_adm_permitted_opens = 0;
3609 }
3610
3611 void
3612 channel_print_adm_permitted_opens(void)
3613 {
3614 int i;
3615
3616 printf("permitopen");
3617 if (num_adm_permitted_opens == 0) {
3618 printf(" any\n");
3619 return;
3620 }
3621 for (i = 0; i < num_adm_permitted_opens; i++)
3622 if (permitted_adm_opens[i].host_to_connect == NULL)
3623 printf(" none");
3624 else
3625 printf(" %s:%d", permitted_adm_opens[i].host_to_connect,
3626 permitted_adm_opens[i].port_to_connect);
3627 printf("\n");
3628 }
3629
3630 /* returns port number, FWD_PERMIT_ANY_PORT or -1 on error */
3631 int
3632 permitopen_port(const char *p)
3633 {
3634 int port;
3635
3636 if (strcmp(p, "*") == 0)
3637 return FWD_PERMIT_ANY_PORT;
3638 if ((port = a2port(p)) > 0)
3639 return port;
3640 return -1;
3641 }
3642
3643 /* Try to start non-blocking connect to next host in cctx list */
3644 static int
3645 connect_next(struct channel_connect *cctx)
3646 {
3647 int sock, saved_errno;
3648 struct sockaddr_un *sunaddr;
3649 char ntop[NI_MAXHOST], strport[MAX(NI_MAXSERV,sizeof(sunaddr->sun_path))];
3650
3651 for (; cctx->ai; cctx->ai = cctx->ai->ai_next) {
3652 switch (cctx->ai->ai_family) {
3653 case AF_UNIX:
3654 /* unix:pathname instead of host:port */
3655 sunaddr = (struct sockaddr_un *)cctx->ai->ai_addr;
3656 strlcpy(ntop, "unix", sizeof(ntop));
3657 strlcpy(strport, sunaddr->sun_path, sizeof(strport));
3658 break;
3659 case AF_INET:
3660 case AF_INET6:
3661 if (getnameinfo(cctx->ai->ai_addr, cctx->ai->ai_addrlen,
3662 ntop, sizeof(ntop), strport, sizeof(strport),
3663 NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
3664 error("connect_next: getnameinfo failed");
3665 continue;
3666 }
3667 break;
3668 default:
3669 continue;
3670 }
3671 if ((sock = socket(cctx->ai->ai_family, cctx->ai->ai_socktype,
3672 cctx->ai->ai_protocol)) == -1) {
3673 if (cctx->ai->ai_next == NULL)
3674 error("socket: %.100s", strerror(errno));
3675 else
3676 verbose("socket: %.100s", strerror(errno));
3677 continue;
3678 }
3679 if (set_nonblock(sock) == -1)
3680 fatal("%s: set_nonblock(%d)", __func__, sock);
3681 if (connect(sock, cctx->ai->ai_addr,
3682 cctx->ai->ai_addrlen) == -1 && errno != EINPROGRESS) {
3683 debug("connect_next: host %.100s ([%.100s]:%s): "
3684 "%.100s", cctx->host, ntop, strport,
3685 strerror(errno));
3686 saved_errno = errno;
3687 close(sock);
3688 errno = saved_errno;
3689 continue; /* fail -- try next */
3690 }
3691 if (cctx->ai->ai_family != AF_UNIX)
3692 set_nodelay(sock);
3693 debug("connect_next: host %.100s ([%.100s]:%s) "
3694 "in progress, fd=%d", cctx->host, ntop, strport, sock);
3695 cctx->ai = cctx->ai->ai_next;
3696 return sock;
3697 }
3698 return -1;
3699 }
3700
3701 static void
3702 channel_connect_ctx_free(struct channel_connect *cctx)
3703 {
3704 free(cctx->host);
3705 if (cctx->aitop) {
3706 if (cctx->aitop->ai_family == AF_UNIX)
3707 free(cctx->aitop);
3708 else
3709 freeaddrinfo(cctx->aitop);
3710 }
3711 memset(cctx, 0, sizeof(*cctx));
3712 }
3713
3714 /* Return CONNECTING channel to remote host:port or local socket path */
3715 static Channel *
3716 connect_to(const char *name, int port, char *ctype, char *rname)
3717 {
3718 struct addrinfo hints;
3719 int gaierr;
3720 int sock = -1;
3721 char strport[NI_MAXSERV];
3722 struct channel_connect cctx;
3723 Channel *c;
3724
3725 memset(&cctx, 0, sizeof(cctx));
3726
3727 if (port == PORT_STREAMLOCAL) {
3728 struct sockaddr_un *sunaddr;
3729 struct addrinfo *ai;
3730
3731 if (strlen(name) > sizeof(sunaddr->sun_path)) {
3732 error("%.100s: %.100s", name, strerror(ENAMETOOLONG));
3733 return (NULL);
3734 }
3735
3736 /*
3737 * Fake up a struct addrinfo for AF_UNIX connections.
3738 * channel_connect_ctx_free() must check ai_family
3739 * and use free() not freeaddirinfo() for AF_UNIX.
3740 */
3741 ai = xmalloc(sizeof(*ai) + sizeof(*sunaddr));
3742 memset(ai, 0, sizeof(*ai) + sizeof(*sunaddr));
3743 ai->ai_addr = (struct sockaddr *)(ai + 1);
3744 ai->ai_addrlen = sizeof(*sunaddr);
3745 ai->ai_family = AF_UNIX;
3746 ai->ai_socktype = SOCK_STREAM;
3747 ai->ai_protocol = PF_UNSPEC;
3748 sunaddr = (struct sockaddr_un *)ai->ai_addr;
3749 sunaddr->sun_family = AF_UNIX;
3750 strlcpy(sunaddr->sun_path, name, sizeof(sunaddr->sun_path));
3751 cctx.aitop = ai;
3752 } else {
3753 memset(&hints, 0, sizeof(hints));
3754 hints.ai_family = IPv4or6;
3755 hints.ai_socktype = SOCK_STREAM;
3756 snprintf(strport, sizeof strport, "%d", port);
3757 if ((gaierr = getaddrinfo(name, strport, &hints, &cctx.aitop)) != 0) {
3758 error("connect_to %.100s: unknown host (%s)", name,
3759 ssh_gai_strerror(gaierr));
3760 return NULL;
3761 }
3762 }
3763
3764 cctx.host = xstrdup(name);
3765 cctx.port = port;
3766 cctx.ai = cctx.aitop;
3767
3768 if ((sock = connect_next(&cctx)) == -1) {
3769 error("connect to %.100s port %d failed: %s",
3770 name, port, strerror(errno));
3771 channel_connect_ctx_free(&cctx);
3772 return NULL;
3773 }
3774 c = channel_new(ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1,
3775 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1);
3776 c->connect_ctx = cctx;
3777 return c;
3778 }
3779
3780 Channel *
3781 channel_connect_by_listen_address(const char *listen_host,
3782 u_short listen_port, char *ctype, char *rname)
3783 {
3784 int i;
3785
3786 for (i = 0; i < num_permitted_opens; i++) {
3787 if (open_listen_match_tcpip(&permitted_opens[i], listen_host,
3788 listen_port, 1)) {
3789 return connect_to(
3790 permitted_opens[i].host_to_connect,
3791 permitted_opens[i].port_to_connect, ctype, rname);
3792 }
3793 }
3794 error("WARNING: Server requests forwarding for unknown listen_port %d",
3795 listen_port);
3796 return NULL;
3797 }
3798
3799 Channel *
3800 channel_connect_by_listen_path(const char *path, char *ctype, char *rname)
3801 {
3802 int i;
3803
3804 for (i = 0; i < num_permitted_opens; i++) {
3805 if (open_listen_match_streamlocal(&permitted_opens[i], path)) {
3806 return connect_to(
3807 permitted_opens[i].host_to_connect,
3808 permitted_opens[i].port_to_connect, ctype, rname);
3809 }
3810 }
3811 error("WARNING: Server requests forwarding for unknown path %.100s",
3812 path);
3813 return NULL;
3814 }
3815
3816 /* Check if connecting to that port is permitted and connect. */
3817 Channel *
3818 channel_connect_to_port(const char *host, u_short port, char *ctype, char *rname)
3819 {
3820 int i, permit, permit_adm = 1;
3821
3822 permit = all_opens_permitted;
3823 if (!permit) {
3824 for (i = 0; i < num_permitted_opens; i++)
3825 if (open_match(&permitted_opens[i], host, port)) {
3826 permit = 1;
3827 break;
3828 }
3829 }
3830
3831 if (num_adm_permitted_opens > 0) {
3832 permit_adm = 0;
3833 for (i = 0; i < num_adm_permitted_opens; i++)
3834 if (open_match(&permitted_adm_opens[i], host, port)) {
3835 permit_adm = 1;
3836 break;
3837 }
3838 }
3839
3840 if (!permit || !permit_adm) {
3841 logit("Received request to connect to host %.100s port %d, "
3842 "but the request was denied.", host, port);
3843 return NULL;
3844 }
3845 return connect_to(host, port, ctype, rname);
3846 }
3847
3848 /* Check if connecting to that path is permitted and connect. */
3849 Channel *
3850 channel_connect_to_path(const char *path, char *ctype, char *rname)
3851 {
3852 int i, permit, permit_adm = 1;
3853
3854 permit = all_opens_permitted;
3855 if (!permit) {
3856 for (i = 0; i < num_permitted_opens; i++)
3857 if (open_match(&permitted_opens[i], path, PORT_STREAMLOCAL)) {
3858 permit = 1;
3859 break;
3860 }
3861 }
3862
3863 if (num_adm_permitted_opens > 0) {
3864 permit_adm = 0;
3865 for (i = 0; i < num_adm_permitted_opens; i++)
3866 if (open_match(&permitted_adm_opens[i], path, PORT_STREAMLOCAL)) {
3867 permit_adm = 1;
3868 break;
3869 }
3870 }
3871
3872 if (!permit || !permit_adm) {
3873 logit("Received request to connect to path %.100s, "
3874 "but the request was denied.", path);
3875 return NULL;
3876 }
3877 return connect_to(path, PORT_STREAMLOCAL, ctype, rname);
3878 }
3879
3880 void
3881 channel_send_window_changes(void)
3882 {
3883 u_int i;
3884 struct winsize ws;
3885
3886 for (i = 0; i < channels_alloc; i++) {
3887 if (channels[i] == NULL || !channels[i]->client_tty ||
3888 channels[i]->type != SSH_CHANNEL_OPEN)
3889 continue;
3890 if (ioctl(channels[i]->rfd, TIOCGWINSZ, &ws) < 0)
3891 continue;
3892 channel_request_start(i, "window-change", 0);
3893 packet_put_int((u_int)ws.ws_col);
3894 packet_put_int((u_int)ws.ws_row);
3895 packet_put_int((u_int)ws.ws_xpixel);
3896 packet_put_int((u_int)ws.ws_ypixel);
3897 packet_send();
3898 }
3899 }
3900
3901 /* -- X11 forwarding */
3902
3903 /*
3904 * Creates an internet domain socket for listening for X11 connections.
3905 * Returns 0 and a suitable display number for the DISPLAY variable
3906 * stored in display_numberp , or -1 if an error occurs.
3907 */
3908 int
3909 x11_create_display_inet(int x11_display_offset, int x11_use_localhost,
3910 int single_connection, u_int *display_numberp, int **chanids)
3911 {
3912 Channel *nc = NULL;
3913 int display_number, sock;
3914 u_short port;
3915 struct addrinfo hints, *ai, *aitop;
3916 char strport[NI_MAXSERV];
3917 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
3918
3919 if (chanids == NULL)
3920 return -1;
3921
3922 for (display_number = x11_display_offset;
3923 display_number < MAX_DISPLAYS;
3924 display_number++) {
3925 port = 6000 + display_number;
3926 memset(&hints, 0, sizeof(hints));
3927 hints.ai_family = IPv4or6;
3928 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE;
3929 hints.ai_socktype = SOCK_STREAM;
3930 snprintf(strport, sizeof strport, "%d", port);
3931 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
3932 error("getaddrinfo: %.100s", ssh_gai_strerror(gaierr));
3933 return -1;
3934 }
3935 for (ai = aitop; ai; ai = ai->ai_next) {
3936 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
3937 continue;
3938 sock = socket(ai->ai_family, ai->ai_socktype,
3939 ai->ai_protocol);
3940 if (sock < 0) {
3941 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)
3942 #ifdef EPFNOSUPPORT
3943 && (errno != EPFNOSUPPORT)
3944 #endif
3945 ) {
3946 error("socket: %.100s", strerror(errno));
3947 freeaddrinfo(aitop);
3948 return -1;
3949 } else {
3950 debug("x11_create_display_inet: Socket family %d not supported",
3951 ai->ai_family);
3952 continue;
3953 }
3954 }
3955 if (ai->ai_family == AF_INET6)
3956 sock_set_v6only(sock);
3957 if (x11_use_localhost)
3958 channel_set_reuseaddr(sock);
3959 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
3960 debug2("bind port %d: %.100s", port, strerror(errno));
3961 close(sock);
3962
3963 for (n = 0; n < num_socks; n++) {
3964 close(socks[n]);
3965 }
3966 num_socks = 0;
3967 break;
3968 }
3969 socks[num_socks++] = sock;
3970 if (num_socks == NUM_SOCKS)
3971 break;
3972 }
3973 freeaddrinfo(aitop);
3974 if (num_socks > 0)
3975 break;
3976 }
3977 if (display_number >= MAX_DISPLAYS) {
3978 error("Failed to allocate internet-domain X11 display socket.");
3979 return -1;
3980 }
3981 /* Start listening for connections on the socket. */
3982 for (n = 0; n < num_socks; n++) {
3983 sock = socks[n];
3984 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
3985 error("listen: %.100s", strerror(errno));
3986 close(sock);
3987 return -1;
3988 }
3989 }
3990
3991 /* Allocate a channel for each socket. */
3992 *chanids = xcalloc(num_socks + 1, sizeof(**chanids));
3993 for (n = 0; n < num_socks; n++) {
3994 sock = socks[n];
3995 /* Is this really necassary? */
3996 if (hpn_disabled)
3997 nc = channel_new("x11 listener",
3998 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
3999 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
4000 0, "X11 inet listener", 1);
4001 else
4002 nc = channel_new("x11 listener",
4003 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
4004 hpn_buffer_size, CHAN_X11_PACKET_DEFAULT,
4005 0, "X11 inet listener", 1);
4006 nc->single_connection = single_connection;
4007 (*chanids)[n] = nc->self;
4008 }
4009 (*chanids)[n] = -1;
4010
4011 /* Return the display number for the DISPLAY environment variable. */
4012 *display_numberp = display_number;
4013 return (0);
4014 }
4015
4016 static int
4017 connect_local_xsocket_path(const char *pathname)
4018 {
4019 int sock;
4020 struct sockaddr_un addr;
4021
4022 sock = socket(AF_UNIX, SOCK_STREAM, 0);
4023 if (sock < 0)
4024 error("socket: %.100s", strerror(errno));
4025 memset(&addr, 0, sizeof(addr));
4026 addr.sun_family = AF_UNIX;
4027 strlcpy(addr.sun_path, pathname, sizeof addr.sun_path);
4028 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0)
4029 return sock;
4030 close(sock);
4031 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
4032 return -1;
4033 }
4034
4035 static int
4036 connect_local_xsocket(u_int dnr)
4037 {
4038 char buf[1024];
4039 snprintf(buf, sizeof buf, _PATH_UNIX_X, dnr);
4040 return connect_local_xsocket_path(buf);
4041 }
4042
4043 int
4044 x11_connect_display(void)
4045 {
4046 u_int display_number;
4047 const char *display;
4048 char buf[1024], *cp;
4049 struct addrinfo hints, *ai, *aitop;
4050 char strport[NI_MAXSERV];
4051 int gaierr, sock = 0;
4052
4053 /* Try to open a socket for the local X server. */
4054 display = getenv("DISPLAY");
4055 if (!display) {
4056 error("DISPLAY not set.");
4057 return -1;
4058 }
4059 /*
4060 * Now we decode the value of the DISPLAY variable and make a
4061 * connection to the real X server.
4062 */
4063
4064 /* Check if the display is from launchd. */
4065 #ifdef __APPLE__
4066 if (strncmp(display, "/tmp/launch", 11) == 0) {
4067 sock = connect_local_xsocket_path(display);
4068 if (sock < 0)
4069 return -1;
4070
4071 /* OK, we now have a connection to the display. */
4072 return sock;
4073 }
4074 #endif
4075 /*
4076 * Check if it is a unix domain socket. Unix domain displays are in
4077 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
4078 */
4079 if (strncmp(display, "unix:", 5) == 0 ||
4080 display[0] == ':') {
4081 /* Connect to the unix domain socket. */
4082 if (sscanf(strrchr(display, ':') + 1, "%u", &display_number) != 1) {
4083 error("Could not parse display number from DISPLAY: %.100s",
4084 display);
4085 return -1;
4086 }
4087 /* Create a socket. */
4088 sock = connect_local_xsocket(display_number);
4089 if (sock < 0)
4090 return -1;
4091
4092 /* OK, we now have a connection to the display. */
4093 return sock;
4094 }
4095 /*
4096 * Connect to an inet socket. The DISPLAY value is supposedly
4097 * hostname:d[.s], where hostname may also be numeric IP address.
4098 */
4099 strlcpy(buf, display, sizeof(buf));
4100 cp = strchr(buf, ':');
4101 if (!cp) {
4102 error("Could not find ':' in DISPLAY: %.100s", display);
4103 return -1;
4104 }
4105 *cp = 0;
4106 /* buf now contains the host name. But first we parse the display number. */
4107 if (sscanf(cp + 1, "%u", &display_number) != 1) {
4108 error("Could not parse display number from DISPLAY: %.100s",
4109 display);
4110 return -1;
4111 }
4112
4113 /* Look up the host address */
4114 memset(&hints, 0, sizeof(hints));
4115 hints.ai_family = IPv4or6;
4116 hints.ai_socktype = SOCK_STREAM;
4117 snprintf(strport, sizeof strport, "%u", 6000 + display_number);
4118 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
4119 error("%.100s: unknown host. (%s)", buf,
4120 ssh_gai_strerror(gaierr));
4121 return -1;
4122 }
4123 for (ai = aitop; ai; ai = ai->ai_next) {
4124 /* Create a socket. */
4125 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
4126 if (sock < 0) {
4127 debug2("socket: %.100s", strerror(errno));
4128 continue;
4129 }
4130 /* Connect it to the display. */
4131 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
4132 debug2("connect %.100s port %u: %.100s", buf,
4133 6000 + display_number, strerror(errno));
4134 close(sock);
4135 continue;
4136 }
4137 /* Success */
4138 break;
4139 }
4140 freeaddrinfo(aitop);
4141 if (!ai) {
4142 error("connect %.100s port %u: %.100s", buf, 6000 + display_number,
4143 strerror(errno));
4144 return -1;
4145 }
4146 set_nodelay(sock);
4147 return sock;
4148 }
4149
4150 /*
4151 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
4152 * the remote channel number. We should do whatever we want, and respond
4153 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
4154 */
4155
4156 /* ARGSUSED */
4157 void
4158 x11_input_open(int type, u_int32_t seq, void *ctxt)
4159 {
4160 Channel *c = NULL;
4161 int remote_id, sock = 0;
4162 char *remote_host;
4163
4164 debug("Received X11 open request.");
4165
4166 remote_id = packet_get_int();
4167
4168 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
4169 remote_host = packet_get_string(NULL);
4170 } else {
4171 remote_host = xstrdup("unknown (remote did not supply name)");
4172 }
4173 packet_check_eom();
4174
4175 /* Obtain a connection to the real X display. */
4176 sock = x11_connect_display();
4177 if (sock != -1) {
4178 /* Allocate a channel for this connection. */
4179 c = channel_new("connected x11 socket",
4180 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
4181 remote_host, 1);
4182 c->remote_id = remote_id;
4183 c->force_drain = 1;
4184 }
4185 free(remote_host);
4186 if (c == NULL) {
4187 /* Send refusal to the remote host. */
4188 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
4189 packet_put_int(remote_id);
4190 } else {
4191 /* Send a confirmation to the remote host. */
4192 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
4193 packet_put_int(remote_id);
4194 packet_put_int(c->self);
4195 }
4196 packet_send();
4197 }
4198
4199 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
4200 /* ARGSUSED */
4201 void
4202 deny_input_open(int type, u_int32_t seq, void *ctxt)
4203 {
4204 int rchan = packet_get_int();
4205
4206 switch (type) {
4207 case SSH_SMSG_AGENT_OPEN:
4208 error("Warning: ssh server tried agent forwarding.");
4209 break;
4210 case SSH_SMSG_X11_OPEN:
4211 error("Warning: ssh server tried X11 forwarding.");
4212 break;
4213 default:
4214 error("deny_input_open: type %d", type);
4215 break;
4216 }
4217 error("Warning: this is probably a break-in attempt by a malicious server.");
4218 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
4219 packet_put_int(rchan);
4220 packet_send();
4221 }
4222
4223 /*
4224 * Requests forwarding of X11 connections, generates fake authentication
4225 * data, and enables authentication spoofing.
4226 * This should be called in the client only.
4227 */
4228 void
4229 x11_request_forwarding_with_spoofing(int client_session_id, const char *disp,
4230 const char *proto, const char *data, int want_reply)
4231 {
4232 u_int data_len = (u_int) strlen(data) / 2;
4233 u_int i, value;
4234 char *new_data;
4235 int screen_number;
4236 const char *cp;
4237 u_int32_t rnd = 0;
4238
4239 if (x11_saved_display == NULL)
4240 x11_saved_display = xstrdup(disp);
4241 else if (strcmp(disp, x11_saved_display) != 0) {
4242 error("x11_request_forwarding_with_spoofing: different "
4243 "$DISPLAY already forwarded");
4244 return;
4245 }
4246
4247 cp = strchr(disp, ':');
4248 if (cp)
4249 cp = strchr(cp, '.');
4250 if (cp)
4251 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL);
4252 else
4253 screen_number = 0;
4254
4255 if (x11_saved_proto == NULL) {
4256 /* Save protocol name. */
4257 x11_saved_proto = xstrdup(proto);
4258 /*
4259 * Extract real authentication data and generate fake data
4260 * of the same length.
4261 */
4262 x11_saved_data = xmalloc(data_len);
4263 x11_fake_data = xmalloc(data_len);
4264 for (i = 0; i < data_len; i++) {
4265 if (sscanf(data + 2 * i, "%2x", &value) != 1)
4266 fatal("x11_request_forwarding: bad "
4267 "authentication data: %.100s", data);
4268 if (i % 4 == 0)
4269 rnd = arc4random();
4270 x11_saved_data[i] = value;
4271 x11_fake_data[i] = rnd & 0xff;
4272 rnd >>= 8;
4273 }
4274 x11_saved_data_len = data_len;
4275 x11_fake_data_len = data_len;
4276 }
4277
4278 /* Convert the fake data into hex. */
4279 new_data = tohex(x11_fake_data, data_len);
4280
4281 /* Send the request packet. */
4282 if (compat20) {
4283 channel_request_start(client_session_id, "x11-req", want_reply);
4284 packet_put_char(0); /* XXX bool single connection */
4285 } else {
4286 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
4287 }
4288 packet_put_cstring(proto);
4289 packet_put_cstring(new_data);
4290 packet_put_int(screen_number);
4291 packet_send();
4292 packet_write_wait();
4293 free(new_data);
4294 }
4295
4296
4297 /* -- agent forwarding */
4298
4299 /* Sends a message to the server to request authentication fd forwarding. */
4300
4301 void
4302 auth_request_forwarding(void)
4303 {
4304 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
4305 packet_send();
4306 packet_write_wait();
4307 }
DragonFly BSD