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[gssapi-openssh.git] / openssh / channels.c
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fa0f0f45 1/* $OpenBSD: channels.c,v 1.270 2007/06/25 08:20:03 dtucker Exp $ */
3c0ef626 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.
473db5ab 17 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved.
3c0ef626 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"
3c0ef626 43
30460aeb 44#include <sys/types.h>
45#include <sys/ioctl.h>
46#include <sys/un.h>
47#include <sys/socket.h>
48#ifdef HAVE_SYS_TIME_H
49# include <sys/time.h>
50#endif
51
52#include <netinet/in.h>
53#include <arpa/inet.h>
54
55#include <errno.h>
56#include <netdb.h>
57#include <stdio.h>
58#include <stdlib.h>
59#include <string.h>
60#include <termios.h>
61#include <unistd.h>
62#include <stdarg.h>
63
64#include "xmalloc.h"
3c0ef626 65#include "ssh.h"
66#include "ssh1.h"
67#include "ssh2.h"
68#include "packet.h"
3c0ef626 69#include "log.h"
70#include "misc.h"
30460aeb 71#include "buffer.h"
3c0ef626 72#include "channels.h"
73#include "compat.h"
74#include "canohost.h"
75#include "key.h"
76#include "authfd.h"
473db5ab 77#include "pathnames.h"
a7213e65 78
3c0ef626 79/* -- channel core */
80
81/*
82 * Pointer to an array containing all allocated channels. The array is
83 * dynamically extended as needed.
84 */
85static Channel **channels = NULL;
86
87/*
88 * Size of the channel array. All slots of the array must always be
89 * initialized (at least the type field); unused slots set to NULL
90 */
473db5ab 91static u_int channels_alloc = 0;
3c0ef626 92
93/*
94 * Maximum file descriptor value used in any of the channels. This is
95 * updated in channel_new.
96 */
97static int channel_max_fd = 0;
98
99
100/* -- tcp forwarding */
101
102/*
103 * Data structure for storing which hosts are permitted for forward requests.
104 * The local sides of any remote forwards are stored in this array to prevent
105 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local
106 * network (which might be behind a firewall).
107 */
108typedef struct {
109 char *host_to_connect; /* Connect to 'host'. */
110 u_short port_to_connect; /* Connect to 'port'. */
111 u_short listen_port; /* Remote side should listen port number. */
112} ForwardPermission;
113
30460aeb 114/* List of all permitted host/port pairs to connect by the user. */
3c0ef626 115static ForwardPermission permitted_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
116
30460aeb 117/* List of all permitted host/port pairs to connect by the admin. */
118static ForwardPermission permitted_adm_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
119
120/* Number of permitted host/port pairs in the array permitted by the user. */
3c0ef626 121static int num_permitted_opens = 0;
30460aeb 122
123/* Number of permitted host/port pair in the array permitted by the admin. */
124static int num_adm_permitted_opens = 0;
125
3c0ef626 126/*
127 * If this is true, all opens are permitted. This is the case on the server
128 * on which we have to trust the client anyway, and the user could do
129 * anything after logging in anyway.
130 */
131static int all_opens_permitted = 0;
132
133
134/* -- X11 forwarding */
135
136/* Maximum number of fake X11 displays to try. */
137#define MAX_DISPLAYS 1000
138
473db5ab 139/* Saved X11 local (client) display. */
140static char *x11_saved_display = NULL;
141
3c0ef626 142/* Saved X11 authentication protocol name. */
143static char *x11_saved_proto = NULL;
144
145/* Saved X11 authentication data. This is the real data. */
146static char *x11_saved_data = NULL;
147static u_int x11_saved_data_len = 0;
148
149/*
150 * Fake X11 authentication data. This is what the server will be sending us;
151 * we should replace any occurrences of this by the real data.
152 */
30460aeb 153static u_char *x11_fake_data = NULL;
3c0ef626 154static u_int x11_fake_data_len;
155
156
157/* -- agent forwarding */
158
159#define NUM_SOCKS 10
160
3c0ef626 161/* AF_UNSPEC or AF_INET or AF_INET6 */
162static int IPv4or6 = AF_UNSPEC;
163
164/* helper */
165static void port_open_helper(Channel *c, char *rtype);
166
167/* -- channel core */
168
169Channel *
08822d99 170channel_by_id(int id)
3c0ef626 171{
172 Channel *c;
173
473db5ab 174 if (id < 0 || (u_int)id >= channels_alloc) {
08822d99 175 logit("channel_by_id: %d: bad id", id);
3c0ef626 176 return NULL;
177 }
178 c = channels[id];
179 if (c == NULL) {
08822d99 180 logit("channel_by_id: %d: bad id: channel free", id);
3c0ef626 181 return NULL;
182 }
183 return c;
184}
185
08822d99 186/*
187 * Returns the channel if it is allowed to receive protocol messages.
188 * Private channels, like listening sockets, may not receive messages.
189 */
190Channel *
191channel_lookup(int id)
192{
193 Channel *c;
194
195 if ((c = channel_by_id(id)) == NULL)
196 return (NULL);
197
30460aeb 198 switch (c->type) {
08822d99 199 case SSH_CHANNEL_X11_OPEN:
200 case SSH_CHANNEL_LARVAL:
201 case SSH_CHANNEL_CONNECTING:
202 case SSH_CHANNEL_DYNAMIC:
203 case SSH_CHANNEL_OPENING:
204 case SSH_CHANNEL_OPEN:
205 case SSH_CHANNEL_INPUT_DRAINING:
206 case SSH_CHANNEL_OUTPUT_DRAINING:
207 return (c);
08822d99 208 }
209 logit("Non-public channel %d, type %d.", id, c->type);
210 return (NULL);
211}
212
3c0ef626 213/*
214 * Register filedescriptors for a channel, used when allocating a channel or
215 * when the channel consumer/producer is ready, e.g. shell exec'd
216 */
3c0ef626 217static void
218channel_register_fds(Channel *c, int rfd, int wfd, int efd,
219 int extusage, int nonblock)
220{
221 /* Update the maximum file descriptor value. */
222 channel_max_fd = MAX(channel_max_fd, rfd);
223 channel_max_fd = MAX(channel_max_fd, wfd);
224 channel_max_fd = MAX(channel_max_fd, efd);
225
226 /* XXX set close-on-exec -markus */
227
228 c->rfd = rfd;
229 c->wfd = wfd;
230 c->sock = (rfd == wfd) ? rfd : -1;
473db5ab 231 c->ctl_fd = -1; /* XXX: set elsewhere */
3c0ef626 232 c->efd = efd;
233 c->extended_usage = extusage;
234
235 /* XXX ugly hack: nonblock is only set by the server */
236 if (nonblock && isatty(c->rfd)) {
473db5ab 237 debug2("channel %d: rfd %d isatty", c->self, c->rfd);
3c0ef626 238 c->isatty = 1;
239 if (!isatty(c->wfd)) {
240 error("channel %d: wfd %d is not a tty?",
241 c->self, c->wfd);
242 }
243 } else {
244 c->isatty = 0;
245 }
473db5ab 246 c->wfd_isatty = isatty(c->wfd);
3c0ef626 247
248 /* enable nonblocking mode */
249 if (nonblock) {
250 if (rfd != -1)
251 set_nonblock(rfd);
252 if (wfd != -1)
253 set_nonblock(wfd);
254 if (efd != -1)
255 set_nonblock(efd);
256 }
257}
258
259/*
260 * Allocate a new channel object and set its type and socket. This will cause
261 * remote_name to be freed.
262 */
3c0ef626 263Channel *
264channel_new(char *ctype, int type, int rfd, int wfd, int efd,
473db5ab 265 u_int window, u_int maxpack, int extusage, char *remote_name, int nonblock)
3c0ef626 266{
473db5ab 267 int found;
268 u_int i;
3c0ef626 269 Channel *c;
270
271 /* Do initial allocation if this is the first call. */
272 if (channels_alloc == 0) {
3c0ef626 273 channels_alloc = 10;
30460aeb 274 channels = xcalloc(channels_alloc, sizeof(Channel *));
3c0ef626 275 for (i = 0; i < channels_alloc; i++)
276 channels[i] = NULL;
3c0ef626 277 }
278 /* Try to find a free slot where to put the new channel. */
279 for (found = -1, i = 0; i < channels_alloc; i++)
280 if (channels[i] == NULL) {
281 /* Found a free slot. */
473db5ab 282 found = (int)i;
3c0ef626 283 break;
284 }
473db5ab 285 if (found < 0) {
3c0ef626 286 /* There are no free slots. Take last+1 slot and expand the array. */
287 found = channels_alloc;
473db5ab 288 if (channels_alloc > 10000)
289 fatal("channel_new: internal error: channels_alloc %d "
290 "too big.", channels_alloc);
30460aeb 291 channels = xrealloc(channels, channels_alloc + 10,
292 sizeof(Channel *));
3c0ef626 293 channels_alloc += 10;
294 debug2("channel: expanding %d", channels_alloc);
3c0ef626 295 for (i = found; i < channels_alloc; i++)
296 channels[i] = NULL;
297 }
298 /* Initialize and return new channel. */
30460aeb 299 c = channels[found] = xcalloc(1, sizeof(Channel));
3c0ef626 300 buffer_init(&c->input);
301 buffer_init(&c->output);
302 buffer_init(&c->extended);
473db5ab 303 c->ostate = CHAN_OUTPUT_OPEN;
304 c->istate = CHAN_INPUT_OPEN;
305 c->flags = 0;
3c0ef626 306 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
307 c->self = found;
308 c->type = type;
309 c->ctype = ctype;
310 c->local_window = window;
311 c->local_window_max = window;
312 c->local_consumed = 0;
313 c->local_maxpacket = maxpack;
473db5ab 314 c->dynamic_window = 0;
3c0ef626 315 c->remote_id = -1;
473db5ab 316 c->remote_name = xstrdup(remote_name);
3c0ef626 317 c->remote_window = 0;
318 c->remote_maxpacket = 0;
3c0ef626 319 c->force_drain = 0;
473db5ab 320 c->single_connection = 0;
3c0ef626 321 c->detach_user = NULL;
08822d99 322 c->detach_close = 0;
473db5ab 323 c->confirm = NULL;
324 c->confirm_ctx = NULL;
3c0ef626 325 c->input_filter = NULL;
08822d99 326 c->output_filter = NULL;
3c0ef626 327 debug("channel %d: new [%s]", found, remote_name);
328 return c;
329}
330
331static int
332channel_find_maxfd(void)
333{
473db5ab 334 u_int i;
335 int max = 0;
3c0ef626 336 Channel *c;
337
338 for (i = 0; i < channels_alloc; i++) {
339 c = channels[i];
340 if (c != NULL) {
341 max = MAX(max, c->rfd);
342 max = MAX(max, c->wfd);
343 max = MAX(max, c->efd);
344 }
345 }
346 return max;
347}
348
349int
350channel_close_fd(int *fdp)
351{
352 int ret = 0, fd = *fdp;
353
354 if (fd != -1) {
355 ret = close(fd);
356 *fdp = -1;
357 if (fd == channel_max_fd)
358 channel_max_fd = channel_find_maxfd();
359 }
360 return ret;
361}
362
363/* Close all channel fd/socket. */
3c0ef626 364static void
365channel_close_fds(Channel *c)
366{
473db5ab 367 debug3("channel %d: close_fds r %d w %d e %d c %d",
368 c->self, c->rfd, c->wfd, c->efd, c->ctl_fd);
3c0ef626 369
370 channel_close_fd(&c->sock);
473db5ab 371 channel_close_fd(&c->ctl_fd);
3c0ef626 372 channel_close_fd(&c->rfd);
373 channel_close_fd(&c->wfd);
374 channel_close_fd(&c->efd);
375}
376
377/* Free the channel and close its fd/socket. */
3c0ef626 378void
379channel_free(Channel *c)
380{
381 char *s;
473db5ab 382 u_int i, n;
3c0ef626 383
384 for (n = 0, i = 0; i < channels_alloc; i++)
385 if (channels[i])
386 n++;
473db5ab 387 debug("channel %d: free: %s, nchannels %u", c->self,
3c0ef626 388 c->remote_name ? c->remote_name : "???", n);
389
390 s = channel_open_message();
473db5ab 391 debug3("channel %d: status: %s", c->self, s);
3c0ef626 392 xfree(s);
393
394 if (c->sock != -1)
395 shutdown(c->sock, SHUT_RDWR);
473db5ab 396 if (c->ctl_fd != -1)
397 shutdown(c->ctl_fd, SHUT_RDWR);
3c0ef626 398 channel_close_fds(c);
399 buffer_free(&c->input);
400 buffer_free(&c->output);
401 buffer_free(&c->extended);
402 if (c->remote_name) {
403 xfree(c->remote_name);
404 c->remote_name = NULL;
405 }
406 channels[c->self] = NULL;
407 xfree(c);
408}
409
410void
411channel_free_all(void)
412{
473db5ab 413 u_int i;
3c0ef626 414
415 for (i = 0; i < channels_alloc; i++)
416 if (channels[i] != NULL)
417 channel_free(channels[i]);
418}
419
420/*
421 * Closes the sockets/fds of all channels. This is used to close extra file
422 * descriptors after a fork.
423 */
3c0ef626 424void
473db5ab 425channel_close_all(void)
3c0ef626 426{
473db5ab 427 u_int i;
3c0ef626 428
429 for (i = 0; i < channels_alloc; i++)
430 if (channels[i] != NULL)
431 channel_close_fds(channels[i]);
432}
433
434/*
435 * Stop listening to channels.
436 */
3c0ef626 437void
438channel_stop_listening(void)
439{
473db5ab 440 u_int i;
3c0ef626 441 Channel *c;
442
443 for (i = 0; i < channels_alloc; i++) {
444 c = channels[i];
445 if (c != NULL) {
446 switch (c->type) {
447 case SSH_CHANNEL_AUTH_SOCKET:
448 case SSH_CHANNEL_PORT_LISTENER:
449 case SSH_CHANNEL_RPORT_LISTENER:
450 case SSH_CHANNEL_X11_LISTENER:
451 channel_close_fd(&c->sock);
452 channel_free(c);
453 break;
454 }
455 }
456 }
457}
458
459/*
460 * Returns true if no channel has too much buffered data, and false if one or
461 * more channel is overfull.
462 */
3c0ef626 463int
473db5ab 464channel_not_very_much_buffered_data(void)
3c0ef626 465{
466 u_int i;
467 Channel *c;
468
469 for (i = 0; i < channels_alloc; i++) {
470 c = channels[i];
471 if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
472#if 0
473 if (!compat20 &&
474 buffer_len(&c->input) > packet_get_maxsize()) {
473db5ab 475 debug2("channel %d: big input buffer %d",
3c0ef626 476 c->self, buffer_len(&c->input));
477 return 0;
478 }
479#endif
480 if (buffer_len(&c->output) > packet_get_maxsize()) {
473db5ab 481 debug2("channel %d: big output buffer %u > %u",
3c0ef626 482 c->self, buffer_len(&c->output),
483 packet_get_maxsize());
484 return 0;
485 }
486 }
487 }
488 return 1;
489}
490
491/* Returns true if any channel is still open. */
3c0ef626 492int
473db5ab 493channel_still_open(void)
3c0ef626 494{
473db5ab 495 u_int i;
3c0ef626 496 Channel *c;
497
498 for (i = 0; i < channels_alloc; i++) {
499 c = channels[i];
500 if (c == NULL)
501 continue;
502 switch (c->type) {
503 case SSH_CHANNEL_X11_LISTENER:
504 case SSH_CHANNEL_PORT_LISTENER:
505 case SSH_CHANNEL_RPORT_LISTENER:
506 case SSH_CHANNEL_CLOSED:
507 case SSH_CHANNEL_AUTH_SOCKET:
508 case SSH_CHANNEL_DYNAMIC:
509 case SSH_CHANNEL_CONNECTING:
510 case SSH_CHANNEL_ZOMBIE:
511 continue;
512 case SSH_CHANNEL_LARVAL:
513 if (!compat20)
514 fatal("cannot happen: SSH_CHANNEL_LARVAL");
515 continue;
516 case SSH_CHANNEL_OPENING:
517 case SSH_CHANNEL_OPEN:
518 case SSH_CHANNEL_X11_OPEN:
519 return 1;
520 case SSH_CHANNEL_INPUT_DRAINING:
521 case SSH_CHANNEL_OUTPUT_DRAINING:
522 if (!compat13)
523 fatal("cannot happen: OUT_DRAIN");
524 return 1;
525 default:
526 fatal("channel_still_open: bad channel type %d", c->type);
527 /* NOTREACHED */
528 }
529 }
530 return 0;
531}
532
533/* Returns the id of an open channel suitable for keepaliving */
3c0ef626 534int
473db5ab 535channel_find_open(void)
3c0ef626 536{
473db5ab 537 u_int i;
3c0ef626 538 Channel *c;
539
540 for (i = 0; i < channels_alloc; i++) {
541 c = channels[i];
473db5ab 542 if (c == NULL || c->remote_id < 0)
3c0ef626 543 continue;
544 switch (c->type) {
545 case SSH_CHANNEL_CLOSED:
546 case SSH_CHANNEL_DYNAMIC:
547 case SSH_CHANNEL_X11_LISTENER:
548 case SSH_CHANNEL_PORT_LISTENER:
549 case SSH_CHANNEL_RPORT_LISTENER:
550 case SSH_CHANNEL_OPENING:
551 case SSH_CHANNEL_CONNECTING:
552 case SSH_CHANNEL_ZOMBIE:
553 continue;
554 case SSH_CHANNEL_LARVAL:
555 case SSH_CHANNEL_AUTH_SOCKET:
556 case SSH_CHANNEL_OPEN:
557 case SSH_CHANNEL_X11_OPEN:
558 return i;
559 case SSH_CHANNEL_INPUT_DRAINING:
560 case SSH_CHANNEL_OUTPUT_DRAINING:
561 if (!compat13)
562 fatal("cannot happen: OUT_DRAIN");
563 return i;
564 default:
565 fatal("channel_find_open: bad channel type %d", c->type);
566 /* NOTREACHED */
567 }
568 }
569 return -1;
570}
571
572
573/*
574 * Returns a message describing the currently open forwarded connections,
575 * suitable for sending to the client. The message contains crlf pairs for
576 * newlines.
577 */
3c0ef626 578char *
473db5ab 579channel_open_message(void)
3c0ef626 580{
581 Buffer buffer;
582 Channel *c;
583 char buf[1024], *cp;
473db5ab 584 u_int i;
3c0ef626 585
586 buffer_init(&buffer);
587 snprintf(buf, sizeof buf, "The following connections are open:\r\n");
588 buffer_append(&buffer, buf, strlen(buf));
589 for (i = 0; i < channels_alloc; i++) {
590 c = channels[i];
591 if (c == NULL)
592 continue;
593 switch (c->type) {
594 case SSH_CHANNEL_X11_LISTENER:
595 case SSH_CHANNEL_PORT_LISTENER:
596 case SSH_CHANNEL_RPORT_LISTENER:
597 case SSH_CHANNEL_CLOSED:
598 case SSH_CHANNEL_AUTH_SOCKET:
599 case SSH_CHANNEL_ZOMBIE:
600 continue;
601 case SSH_CHANNEL_LARVAL:
602 case SSH_CHANNEL_OPENING:
603 case SSH_CHANNEL_CONNECTING:
604 case SSH_CHANNEL_DYNAMIC:
605 case SSH_CHANNEL_OPEN:
606 case SSH_CHANNEL_X11_OPEN:
607 case SSH_CHANNEL_INPUT_DRAINING:
608 case SSH_CHANNEL_OUTPUT_DRAINING:
473db5ab 609 snprintf(buf, sizeof buf,
610 " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d cfd %d)\r\n",
3c0ef626 611 c->self, c->remote_name,
612 c->type, c->remote_id,
613 c->istate, buffer_len(&c->input),
614 c->ostate, buffer_len(&c->output),
473db5ab 615 c->rfd, c->wfd, c->ctl_fd);
3c0ef626 616 buffer_append(&buffer, buf, strlen(buf));
617 continue;
618 default:
619 fatal("channel_open_message: bad channel type %d", c->type);
620 /* NOTREACHED */
621 }
622 }
623 buffer_append(&buffer, "\0", 1);
624 cp = xstrdup(buffer_ptr(&buffer));
625 buffer_free(&buffer);
626 return cp;
627}
628
629void
630channel_send_open(int id)
631{
632 Channel *c = channel_lookup(id);
473db5ab 633
3c0ef626 634 if (c == NULL) {
473db5ab 635 logit("channel_send_open: %d: bad id", id);
3c0ef626 636 return;
637 }
473db5ab 638 debug2("channel %d: send open", id);
3c0ef626 639 packet_start(SSH2_MSG_CHANNEL_OPEN);
640 packet_put_cstring(c->ctype);
641 packet_put_int(c->self);
642 packet_put_int(c->local_window);
643 packet_put_int(c->local_maxpacket);
644 packet_send();
645}
646
3c0ef626 647void
648channel_request_start(int id, char *service, int wantconfirm)
649{
650 Channel *c = channel_lookup(id);
473db5ab 651
3c0ef626 652 if (c == NULL) {
473db5ab 653 logit("channel_request_start: %d: unknown channel id", id);
3c0ef626 654 return;
655 }
473db5ab 656 debug2("channel %d: request %s confirm %d", id, service, wantconfirm);
3c0ef626 657 packet_start(SSH2_MSG_CHANNEL_REQUEST);
658 packet_put_int(c->remote_id);
659 packet_put_cstring(service);
660 packet_put_char(wantconfirm);
661}
30460aeb 662
3c0ef626 663void
473db5ab 664channel_register_confirm(int id, channel_callback_fn *fn, void *ctx)
3c0ef626 665{
666 Channel *c = channel_lookup(id);
473db5ab 667
3c0ef626 668 if (c == NULL) {
473db5ab 669 logit("channel_register_comfirm: %d: bad id", id);
3c0ef626 670 return;
671 }
473db5ab 672 c->confirm = fn;
673 c->confirm_ctx = ctx;
3c0ef626 674}
30460aeb 675
3c0ef626 676void
08822d99 677channel_register_cleanup(int id, channel_callback_fn *fn, int do_close)
3c0ef626 678{
08822d99 679 Channel *c = channel_by_id(id);
473db5ab 680
3c0ef626 681 if (c == NULL) {
473db5ab 682 logit("channel_register_cleanup: %d: bad id", id);
3c0ef626 683 return;
684 }
685 c->detach_user = fn;
08822d99 686 c->detach_close = do_close;
3c0ef626 687}
30460aeb 688
3c0ef626 689void
690channel_cancel_cleanup(int id)
691{
08822d99 692 Channel *c = channel_by_id(id);
473db5ab 693
3c0ef626 694 if (c == NULL) {
473db5ab 695 logit("channel_cancel_cleanup: %d: bad id", id);
3c0ef626 696 return;
697 }
698 c->detach_user = NULL;
08822d99 699 c->detach_close = 0;
3c0ef626 700}
30460aeb 701
3c0ef626 702void
08822d99 703channel_register_filter(int id, channel_infilter_fn *ifn,
704 channel_outfilter_fn *ofn)
3c0ef626 705{
706 Channel *c = channel_lookup(id);
473db5ab 707
3c0ef626 708 if (c == NULL) {
473db5ab 709 logit("channel_register_filter: %d: bad id", id);
3c0ef626 710 return;
711 }
08822d99 712 c->input_filter = ifn;
713 c->output_filter = ofn;
3c0ef626 714}
715
716void
717channel_set_fds(int id, int rfd, int wfd, int efd,
473db5ab 718 int extusage, int nonblock, u_int window_max)
3c0ef626 719{
720 Channel *c = channel_lookup(id);
473db5ab 721
3c0ef626 722 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
723 fatal("channel_activate for non-larval channel %d.", id);
724 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
725 c->type = SSH_CHANNEL_OPEN;
473db5ab 726 c->local_window = c->local_window_max = window_max;
3c0ef626 727 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
728 packet_put_int(c->remote_id);
729 packet_put_int(c->local_window);
730 packet_send();
731}
732
733/*
734 * 'channel_pre*' are called just before select() to add any bits relevant to
735 * channels in the select bitmasks.
736 */
737/*
738 * 'channel_post*': perform any appropriate operations for channels which
739 * have events pending.
740 */
30460aeb 741typedef void chan_fn(Channel *c, fd_set *readset, fd_set *writeset);
3c0ef626 742chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
743chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
744
30460aeb 745/* ARGSUSED */
3c0ef626 746static void
30460aeb 747channel_pre_listener(Channel *c, fd_set *readset, fd_set *writeset)
3c0ef626 748{
749 FD_SET(c->sock, readset);
750}
751
30460aeb 752/* ARGSUSED */
3c0ef626 753static void
30460aeb 754channel_pre_connecting(Channel *c, fd_set *readset, fd_set *writeset)
3c0ef626 755{
756 debug3("channel %d: waiting for connection", c->self);
757 FD_SET(c->sock, writeset);
758}
759
760static void
30460aeb 761channel_pre_open_13(Channel *c, fd_set *readset, fd_set *writeset)
3c0ef626 762{
763 if (buffer_len(&c->input) < packet_get_maxsize())
764 FD_SET(c->sock, readset);
765 if (buffer_len(&c->output) > 0)
766 FD_SET(c->sock, writeset);
767}
768
f713db99 769int channel_tcpwinsz () {
770 u_int32_t tcpwinsz = 0;
771 socklen_t optsz = sizeof(tcpwinsz);
772 int ret = -1;
773 if(!packet_connection_is_on_socket())
774 return(131072);
775 ret = getsockopt(packet_get_connection_in(),
776 SOL_SOCKET, SO_RCVBUF, &tcpwinsz, &optsz);
777 if ((ret == 0) && tcpwinsz > BUFFER_MAX_LEN_HPN)
778 tcpwinsz = BUFFER_MAX_LEN_HPN;
779 debug2("tcpwinsz: %d for connection: %d", tcpwinsz,
780 packet_get_connection_in());
781 return(tcpwinsz);
782}
783
3c0ef626 784static void
30460aeb 785channel_pre_open(Channel *c, fd_set *readset, fd_set *writeset)
3c0ef626 786{
473db5ab 787 u_int limit = compat20 ? c->remote_window : packet_get_maxsize();
f472818d 788
f713db99 789 /* check buffer limits */
790 if (!c->tcpwinsz)
791 c->tcpwinsz = channel_tcpwinsz();
792 if (c->dynamic_window > 0)
793 c->tcpwinsz = channel_tcpwinsz();
794
795 limit = MIN(limit, 2 * c->tcpwinsz);
796
3c0ef626 797 if (c->istate == CHAN_INPUT_OPEN &&
473db5ab 798 limit > 0 &&
30460aeb 799 buffer_len(&c->input) < limit &&
800 buffer_check_alloc(&c->input, CHAN_RBUF))
3c0ef626 801 FD_SET(c->rfd, readset);
802 if (c->ostate == CHAN_OUTPUT_OPEN ||
803 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
804 if (buffer_len(&c->output) > 0) {
805 FD_SET(c->wfd, writeset);
806 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
473db5ab 807 if (CHANNEL_EFD_OUTPUT_ACTIVE(c))
808 debug2("channel %d: obuf_empty delayed efd %d/(%d)",
809 c->self, c->efd, buffer_len(&c->extended));
810 else
811 chan_obuf_empty(c);
3c0ef626 812 }
813 }
814 /** XXX check close conditions, too */
473db5ab 815 if (compat20 && c->efd != -1) {
3c0ef626 816 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
817 buffer_len(&c->extended) > 0)
818 FD_SET(c->efd, writeset);
473db5ab 819 else if (!(c->flags & CHAN_EOF_SENT) &&
820 c->extended_usage == CHAN_EXTENDED_READ &&
3c0ef626 821 buffer_len(&c->extended) < c->remote_window)
822 FD_SET(c->efd, readset);
823 }
473db5ab 824 /* XXX: What about efd? races? */
825 if (compat20 && c->ctl_fd != -1 &&
826 c->istate == CHAN_INPUT_OPEN && c->ostate == CHAN_OUTPUT_OPEN)
827 FD_SET(c->ctl_fd, readset);
3c0ef626 828}
829
30460aeb 830/* ARGSUSED */
3c0ef626 831static void
30460aeb 832channel_pre_input_draining(Channel *c, fd_set *readset, fd_set *writeset)
3c0ef626 833{
834 if (buffer_len(&c->input) == 0) {
835 packet_start(SSH_MSG_CHANNEL_CLOSE);
836 packet_put_int(c->remote_id);
837 packet_send();
838 c->type = SSH_CHANNEL_CLOSED;
473db5ab 839 debug2("channel %d: closing after input drain.", c->self);
3c0ef626 840 }
841}
842
30460aeb 843/* ARGSUSED */
3c0ef626 844static void
30460aeb 845channel_pre_output_draining(Channel *c, fd_set *readset, fd_set *writeset)
3c0ef626 846{
847 if (buffer_len(&c->output) == 0)
848 chan_mark_dead(c);
849 else
850 FD_SET(c->sock, writeset);
851}
852
853/*
854 * This is a special state for X11 authentication spoofing. An opened X11
855 * connection (when authentication spoofing is being done) remains in this
856 * state until the first packet has been completely read. The authentication
857 * data in that packet is then substituted by the real data if it matches the
858 * fake data, and the channel is put into normal mode.
859 * XXX All this happens at the client side.
860 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
861 */
862static int
863x11_open_helper(Buffer *b)
864{
865 u_char *ucp;
866 u_int proto_len, data_len;
867
868 /* Check if the fixed size part of the packet is in buffer. */
869 if (buffer_len(b) < 12)
870 return 0;
871
872 /* Parse the lengths of variable-length fields. */
473db5ab 873 ucp = buffer_ptr(b);
3c0ef626 874 if (ucp[0] == 0x42) { /* Byte order MSB first. */
875 proto_len = 256 * ucp[6] + ucp[7];
876 data_len = 256 * ucp[8] + ucp[9];
877 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
878 proto_len = ucp[6] + 256 * ucp[7];
879 data_len = ucp[8] + 256 * ucp[9];
880 } else {
473db5ab 881 debug2("Initial X11 packet contains bad byte order byte: 0x%x",
882 ucp[0]);
3c0ef626 883 return -1;
884 }
885
886 /* Check if the whole packet is in buffer. */
887 if (buffer_len(b) <
888 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
889 return 0;
890
891 /* Check if authentication protocol matches. */
892 if (proto_len != strlen(x11_saved_proto) ||
893 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
473db5ab 894 debug2("X11 connection uses different authentication protocol.");
3c0ef626 895 return -1;
896 }
897 /* Check if authentication data matches our fake data. */
898 if (data_len != x11_fake_data_len ||
899 memcmp(ucp + 12 + ((proto_len + 3) & ~3),
900 x11_fake_data, x11_fake_data_len) != 0) {
473db5ab 901 debug2("X11 auth data does not match fake data.");
3c0ef626 902 return -1;
903 }
904 /* Check fake data length */
905 if (x11_fake_data_len != x11_saved_data_len) {
906 error("X11 fake_data_len %d != saved_data_len %d",
907 x11_fake_data_len, x11_saved_data_len);
908 return -1;
909 }
910 /*
911 * Received authentication protocol and data match
912 * our fake data. Substitute the fake data with real
913 * data.
914 */
915 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
916 x11_saved_data, x11_saved_data_len);
917 return 1;
918}
919
920static void
30460aeb 921channel_pre_x11_open_13(Channel *c, fd_set *readset, fd_set *writeset)
3c0ef626 922{
923 int ret = x11_open_helper(&c->output);
473db5ab 924
3c0ef626 925 if (ret == 1) {
926 /* Start normal processing for the channel. */
927 c->type = SSH_CHANNEL_OPEN;
928 channel_pre_open_13(c, readset, writeset);
929 } else if (ret == -1) {
930 /*
931 * We have received an X11 connection that has bad
932 * authentication information.
933 */
473db5ab 934 logit("X11 connection rejected because of wrong authentication.");
3c0ef626 935 buffer_clear(&c->input);
936 buffer_clear(&c->output);
937 channel_close_fd(&c->sock);
938 c->sock = -1;
939 c->type = SSH_CHANNEL_CLOSED;
940 packet_start(SSH_MSG_CHANNEL_CLOSE);
941 packet_put_int(c->remote_id);
942 packet_send();
943 }
944}
945
946static void
30460aeb 947channel_pre_x11_open(Channel *c, fd_set *readset, fd_set *writeset)
3c0ef626 948{
949 int ret = x11_open_helper(&c->output);
950
951 /* c->force_drain = 1; */
952
953 if (ret == 1) {
954 c->type = SSH_CHANNEL_OPEN;
473db5ab 955 channel_pre_open(c, readset, writeset);
956 } else if (ret == -1) {
957 logit("X11 connection rejected because of wrong authentication.");
958 debug2("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
959 chan_read_failed(c);
960 buffer_clear(&c->input);
961 chan_ibuf_empty(c);
962 buffer_clear(&c->output);
963 /* for proto v1, the peer will send an IEOF */
3c0ef626 964 if (compat20)
473db5ab 965 chan_write_failed(c);
3c0ef626 966 else
473db5ab 967 c->type = SSH_CHANNEL_OPEN;
968 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
3c0ef626 969 }
970}
971
972/* try to decode a socks4 header */
30460aeb 973/* ARGSUSED */
3c0ef626 974static int
30460aeb 975channel_decode_socks4(Channel *c, fd_set *readset, fd_set *writeset)
3c0ef626 976{
473db5ab 977 char *p, *host;
978 u_int len, have, i, found;
979 char username[256];
3c0ef626 980 struct {
981 u_int8_t version;
982 u_int8_t command;
983 u_int16_t dest_port;
984 struct in_addr dest_addr;
985 } s4_req, s4_rsp;
986
987 debug2("channel %d: decode socks4", c->self);
988
989 have = buffer_len(&c->input);
990 len = sizeof(s4_req);
991 if (have < len)
992 return 0;
993 p = buffer_ptr(&c->input);
994 for (found = 0, i = len; i < have; i++) {
995 if (p[i] == '\0') {
996 found = 1;
997 break;
998 }
999 if (i > 1024) {
1000 /* the peer is probably sending garbage */
1001 debug("channel %d: decode socks4: too long",
1002 c->self);
1003 return -1;
1004 }
1005 }
1006 if (!found)
1007 return 0;
1008 buffer_get(&c->input, (char *)&s4_req.version, 1);
1009 buffer_get(&c->input, (char *)&s4_req.command, 1);
1010 buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
1011 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
1012 have = buffer_len(&c->input);
1013 p = buffer_ptr(&c->input);
1014 len = strlen(p);
1015 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
1016 if (len > have)
1017 fatal("channel %d: decode socks4: len %d > have %d",
1018 c->self, len, have);
1019 strlcpy(username, p, sizeof(username));
1020 buffer_consume(&c->input, len);
1021 buffer_consume(&c->input, 1); /* trailing '\0' */
1022
1023 host = inet_ntoa(s4_req.dest_addr);
1024 strlcpy(c->path, host, sizeof(c->path));
1025 c->host_port = ntohs(s4_req.dest_port);
473db5ab 1026
1027 debug2("channel %d: dynamic request: socks4 host %s port %u command %u",
3c0ef626 1028 c->self, host, c->host_port, s4_req.command);
1029
1030 if (s4_req.command != 1) {
1031 debug("channel %d: cannot handle: socks4 cn %d",
1032 c->self, s4_req.command);
1033 return -1;
1034 }
1035 s4_rsp.version = 0; /* vn: 0 for reply */
1036 s4_rsp.command = 90; /* cd: req granted */
1037 s4_rsp.dest_port = 0; /* ignored */
1038 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
30460aeb 1039 buffer_append(&c->output, &s4_rsp, sizeof(s4_rsp));
3c0ef626 1040 return 1;
1041}
1042
473db5ab 1043/* try to decode a socks5 header */
1044#define SSH_SOCKS5_AUTHDONE 0x1000
1045#define SSH_SOCKS5_NOAUTH 0x00
1046#define SSH_SOCKS5_IPV4 0x01
1047#define SSH_SOCKS5_DOMAIN 0x03
1048#define SSH_SOCKS5_IPV6 0x04
1049#define SSH_SOCKS5_CONNECT 0x01
1050#define SSH_SOCKS5_SUCCESS 0x00
1051
30460aeb 1052/* ARGSUSED */
473db5ab 1053static int
30460aeb 1054channel_decode_socks5(Channel *c, fd_set *readset, fd_set *writeset)
473db5ab 1055{
1056 struct {
1057 u_int8_t version;
1058 u_int8_t command;
1059 u_int8_t reserved;
1060 u_int8_t atyp;
1061 } s5_req, s5_rsp;
1062 u_int16_t dest_port;
1063 u_char *p, dest_addr[255+1];
30460aeb 1064 u_int have, need, i, found, nmethods, addrlen, af;
473db5ab 1065
1066 debug2("channel %d: decode socks5", c->self);
1067 p = buffer_ptr(&c->input);
1068 if (p[0] != 0x05)
1069 return -1;
1070 have = buffer_len(&c->input);
1071 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) {
1072 /* format: ver | nmethods | methods */
1073 if (have < 2)
1074 return 0;
1075 nmethods = p[1];
1076 if (have < nmethods + 2)
1077 return 0;
1078 /* look for method: "NO AUTHENTICATION REQUIRED" */
0b90ac93 1079 for (found = 0, i = 2; i < nmethods + 2; i++) {
30460aeb 1080 if (p[i] == SSH_SOCKS5_NOAUTH) {
473db5ab 1081 found = 1;
1082 break;
1083 }
1084 }
1085 if (!found) {
1086 debug("channel %d: method SSH_SOCKS5_NOAUTH not found",
1087 c->self);
1088 return -1;
1089 }
1090 buffer_consume(&c->input, nmethods + 2);
1091 buffer_put_char(&c->output, 0x05); /* version */
1092 buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH); /* method */
1093 FD_SET(c->sock, writeset);
1094 c->flags |= SSH_SOCKS5_AUTHDONE;
1095 debug2("channel %d: socks5 auth done", c->self);
1096 return 0; /* need more */
1097 }
1098 debug2("channel %d: socks5 post auth", c->self);
1099 if (have < sizeof(s5_req)+1)
1100 return 0; /* need more */
30460aeb 1101 memcpy(&s5_req, p, sizeof(s5_req));
473db5ab 1102 if (s5_req.version != 0x05 ||
1103 s5_req.command != SSH_SOCKS5_CONNECT ||
1104 s5_req.reserved != 0x00) {
1105 debug2("channel %d: only socks5 connect supported", c->self);
1106 return -1;
1107 }
1108 switch (s5_req.atyp){
1109 case SSH_SOCKS5_IPV4:
1110 addrlen = 4;
1111 af = AF_INET;
1112 break;
1113 case SSH_SOCKS5_DOMAIN:
1114 addrlen = p[sizeof(s5_req)];
1115 af = -1;
1116 break;
1117 case SSH_SOCKS5_IPV6:
1118 addrlen = 16;
1119 af = AF_INET6;
1120 break;
1121 default:
1122 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp);
1123 return -1;
1124 }
30460aeb 1125 need = sizeof(s5_req) + addrlen + 2;
1126 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1127 need++;
1128 if (have < need)
473db5ab 1129 return 0;
1130 buffer_consume(&c->input, sizeof(s5_req));
1131 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1132 buffer_consume(&c->input, 1); /* host string length */
1133 buffer_get(&c->input, (char *)&dest_addr, addrlen);
1134 buffer_get(&c->input, (char *)&dest_port, 2);
1135 dest_addr[addrlen] = '\0';
1136 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1137 strlcpy(c->path, (char *)dest_addr, sizeof(c->path));
1138 else if (inet_ntop(af, dest_addr, c->path, sizeof(c->path)) == NULL)
1139 return -1;
1140 c->host_port = ntohs(dest_port);
1141
1142 debug2("channel %d: dynamic request: socks5 host %s port %u command %u",
1143 c->self, c->path, c->host_port, s5_req.command);
1144
1145 s5_rsp.version = 0x05;
1146 s5_rsp.command = SSH_SOCKS5_SUCCESS;
1147 s5_rsp.reserved = 0; /* ignored */
1148 s5_rsp.atyp = SSH_SOCKS5_IPV4;
1149 ((struct in_addr *)&dest_addr)->s_addr = INADDR_ANY;
1150 dest_port = 0; /* ignored */
1151
30460aeb 1152 buffer_append(&c->output, &s5_rsp, sizeof(s5_rsp));
1153 buffer_append(&c->output, &dest_addr, sizeof(struct in_addr));
1154 buffer_append(&c->output, &dest_port, sizeof(dest_port));
473db5ab 1155 return 1;
1156}
1157
3c0ef626 1158/* dynamic port forwarding */
1159static void
30460aeb 1160channel_pre_dynamic(Channel *c, fd_set *readset, fd_set *writeset)
3c0ef626 1161{
1162 u_char *p;
473db5ab 1163 u_int have;
1164 int ret;
3c0ef626 1165
1166 have = buffer_len(&c->input);
1167 c->delayed = 0;
1168 debug2("channel %d: pre_dynamic: have %d", c->self, have);
1169 /* buffer_dump(&c->input); */
1170 /* check if the fixed size part of the packet is in buffer. */
473db5ab 1171 if (have < 3) {
3c0ef626 1172 /* need more */
1173 FD_SET(c->sock, readset);
1174 return;
1175 }
1176 /* try to guess the protocol */
1177 p = buffer_ptr(&c->input);
1178 switch (p[0]) {
1179 case 0x04:
1180 ret = channel_decode_socks4(c, readset, writeset);
1181 break;
473db5ab 1182 case 0x05:
1183 ret = channel_decode_socks5(c, readset, writeset);
1184 break;
3c0ef626 1185 default:
1186 ret = -1;
1187 break;
1188 }
1189 if (ret < 0) {
1190 chan_mark_dead(c);
1191 } else if (ret == 0) {
1192 debug2("channel %d: pre_dynamic: need more", c->self);
1193 /* need more */
1194 FD_SET(c->sock, readset);
1195 } else {
1196 /* switch to the next state */
1197 c->type = SSH_CHANNEL_OPENING;
1198 port_open_helper(c, "direct-tcpip");
1199 }
1200}
1201
1202/* This is our fake X11 server socket. */
30460aeb 1203/* ARGSUSED */
3c0ef626 1204static void
30460aeb 1205channel_post_x11_listener(Channel *c, fd_set *readset, fd_set *writeset)
3c0ef626 1206{
1207 Channel *nc;
1208 struct sockaddr addr;
1209 int newsock;
1210 socklen_t addrlen;
1211 char buf[16384], *remote_ipaddr;
1212 int remote_port;
1213
1214 if (FD_ISSET(c->sock, readset)) {
1215 debug("X11 connection requested.");
1216 addrlen = sizeof(addr);
1217 newsock = accept(c->sock, &addr, &addrlen);
473db5ab 1218 if (c->single_connection) {
1219 debug2("single_connection: closing X11 listener.");
1220 channel_close_fd(&c->sock);
1221 chan_mark_dead(c);
1222 }
3c0ef626 1223 if (newsock < 0) {
1224 error("accept: %.100s", strerror(errno));
1225 return;
1226 }
473db5ab 1227 set_nodelay(newsock);
3c0ef626 1228 remote_ipaddr = get_peer_ipaddr(newsock);
1229 remote_port = get_peer_port(newsock);
1230 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1231 remote_ipaddr, remote_port);
1232
1233 nc = channel_new("accepted x11 socket",
1234 SSH_CHANNEL_OPENING, newsock, newsock, -1,
473db5ab 1235 c->local_window_max, c->local_maxpacket, 0, buf, 1);
3c0ef626 1236 if (compat20) {
1237 packet_start(SSH2_MSG_CHANNEL_OPEN);
1238 packet_put_cstring("x11");
1239 packet_put_int(nc->self);
473db5ab 1240 packet_put_int(nc->local_window_max);
1241 packet_put_int(nc->local_maxpacket);
3c0ef626 1242 /* originator ipaddr and port */
1243 packet_put_cstring(remote_ipaddr);
1244 if (datafellows & SSH_BUG_X11FWD) {
473db5ab 1245 debug2("ssh2 x11 bug compat mode");
3c0ef626 1246 } else {
1247 packet_put_int(remote_port);
1248 }
1249 packet_send();
1250 } else {
1251 packet_start(SSH_SMSG_X11_OPEN);
1252 packet_put_int(nc->self);
1253 if (packet_get_protocol_flags() &
1254 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1255 packet_put_cstring(buf);
1256 packet_send();
1257 }
1258 xfree(remote_ipaddr);
1259 }
1260}
1261
1262static void
1263port_open_helper(Channel *c, char *rtype)
1264{
1265 int direct;
1266 char buf[1024];
1267 char *remote_ipaddr = get_peer_ipaddr(c->sock);
473db5ab 1268 int remote_port = get_peer_port(c->sock);
3c0ef626 1269
1270 direct = (strcmp(rtype, "direct-tcpip") == 0);
1271
1272 snprintf(buf, sizeof buf,
1273 "%s: listening port %d for %.100s port %d, "
1274 "connect from %.200s port %d",
1275 rtype, c->listening_port, c->path, c->host_port,
1276 remote_ipaddr, remote_port);
1277
1278 xfree(c->remote_name);
1279 c->remote_name = xstrdup(buf);
1280
1281 if (compat20) {
1282 packet_start(SSH2_MSG_CHANNEL_OPEN);
1283 packet_put_cstring(rtype);
1284 packet_put_int(c->self);
1285 packet_put_int(c->local_window_max);
1286 packet_put_int(c->local_maxpacket);
1287 if (direct) {
1288 /* target host, port */
1289 packet_put_cstring(c->path);
1290 packet_put_int(c->host_port);
1291 } else {
1292 /* listen address, port */
1293 packet_put_cstring(c->path);
1294 packet_put_int(c->listening_port);
1295 }
1296 /* originator host and port */
1297 packet_put_cstring(remote_ipaddr);
473db5ab 1298 packet_put_int((u_int)remote_port);
3c0ef626 1299 packet_send();
1300 } else {
1301 packet_start(SSH_MSG_PORT_OPEN);
1302 packet_put_int(c->self);
1303 packet_put_cstring(c->path);
1304 packet_put_int(c->host_port);
1305 if (packet_get_protocol_flags() &
1306 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1307 packet_put_cstring(c->remote_name);
1308 packet_send();
1309 }
1310 xfree(remote_ipaddr);
1311}
1312
08822d99 1313static void
1314channel_set_reuseaddr(int fd)
1315{
1316 int on = 1;
1317
1318 /*
1319 * Set socket options.
1320 * Allow local port reuse in TIME_WAIT.
1321 */
1322 if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1)
1323 error("setsockopt SO_REUSEADDR fd %d: %s", fd, strerror(errno));
1324}
1325
3c0ef626 1326/*
1327 * This socket is listening for connections to a forwarded TCP/IP port.
1328 */
30460aeb 1329/* ARGSUSED */
3c0ef626 1330static void
30460aeb 1331channel_post_port_listener(Channel *c, fd_set *readset, fd_set *writeset)
3c0ef626 1332{
1333 Channel *nc;
1334 struct sockaddr addr;
1335 int newsock, nextstate;
1336 socklen_t addrlen;
1337 char *rtype;
1338
1339 if (FD_ISSET(c->sock, readset)) {
1340 debug("Connection to port %d forwarding "
1341 "to %.100s port %d requested.",
1342 c->listening_port, c->path, c->host_port);
1343
1344 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1345 nextstate = SSH_CHANNEL_OPENING;
1346 rtype = "forwarded-tcpip";
1347 } else {
1348 if (c->host_port == 0) {
1349 nextstate = SSH_CHANNEL_DYNAMIC;
1350 rtype = "dynamic-tcpip";
1351 } else {
1352 nextstate = SSH_CHANNEL_OPENING;
1353 rtype = "direct-tcpip";
1354 }
1355 }
1356
1357 addrlen = sizeof(addr);
1358 newsock = accept(c->sock, &addr, &addrlen);
1359 if (newsock < 0) {
1360 error("accept: %.100s", strerror(errno));
1361 return;
1362 }
473db5ab 1363 set_nodelay(newsock);
1364 nc = channel_new(rtype, nextstate, newsock, newsock, -1,
1365 c->local_window_max, c->local_maxpacket, 0, rtype, 1);
3c0ef626 1366 nc->listening_port = c->listening_port;
1367 nc->host_port = c->host_port;
1368 strlcpy(nc->path, c->path, sizeof(nc->path));
1369
1370 if (nextstate == SSH_CHANNEL_DYNAMIC) {
1371 /*
1372 * do not call the channel_post handler until
1373 * this flag has been reset by a pre-handler.
1374 * otherwise the FD_ISSET calls might overflow
1375 */
1376 nc->delayed = 1;
1377 } else {
1378 port_open_helper(nc, rtype);
1379 }
1380 }
1381}
1382
1383/*
1384 * This is the authentication agent socket listening for connections from
1385 * clients.
1386 */
30460aeb 1387/* ARGSUSED */
3c0ef626 1388static void
30460aeb 1389channel_post_auth_listener(Channel *c, fd_set *readset, fd_set *writeset)
3c0ef626 1390{
1391 Channel *nc;
3c0ef626 1392 int newsock;
1393 struct sockaddr addr;
1394 socklen_t addrlen;
1395
1396 if (FD_ISSET(c->sock, readset)) {
1397 addrlen = sizeof(addr);
1398 newsock = accept(c->sock, &addr, &addrlen);
1399 if (newsock < 0) {
1400 error("accept from auth socket: %.100s", strerror(errno));
1401 return;
1402 }
3c0ef626 1403 nc = channel_new("accepted auth socket",
1404 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1405 c->local_window_max, c->local_maxpacket,
473db5ab 1406 0, "accepted auth socket", 1);
3c0ef626 1407 if (compat20) {
1408 packet_start(SSH2_MSG_CHANNEL_OPEN);
1409 packet_put_cstring("auth-agent@openssh.com");
1410 packet_put_int(nc->self);
1411 packet_put_int(c->local_window_max);
1412 packet_put_int(c->local_maxpacket);
1413 } else {
1414 packet_start(SSH_SMSG_AGENT_OPEN);
1415 packet_put_int(nc->self);
1416 }
1417 packet_send();
1418 }
1419}
1420
30460aeb 1421/* ARGSUSED */
3c0ef626 1422static void
30460aeb 1423channel_post_connecting(Channel *c, fd_set *readset, fd_set *writeset)
3c0ef626 1424{
1425 int err = 0;
1426 socklen_t sz = sizeof(err);
1427
1428 if (FD_ISSET(c->sock, writeset)) {
473db5ab 1429 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) {
3c0ef626 1430 err = errno;
1431 error("getsockopt SO_ERROR failed");
1432 }
1433 if (err == 0) {
1434 debug("channel %d: connected", c->self);
1435 c->type = SSH_CHANNEL_OPEN;
1436 if (compat20) {
1437 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1438 packet_put_int(c->remote_id);
1439 packet_put_int(c->self);
1440 packet_put_int(c->local_window);
1441 packet_put_int(c->local_maxpacket);
1442 } else {
1443 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1444 packet_put_int(c->remote_id);
1445 packet_put_int(c->self);
1446 }
1447 } else {
1448 debug("channel %d: not connected: %s",
1449 c->self, strerror(err));
1450 if (compat20) {
1451 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1452 packet_put_int(c->remote_id);
1453 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1454 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1455 packet_put_cstring(strerror(err));
1456 packet_put_cstring("");
1457 }
1458 } else {
1459 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1460 packet_put_int(c->remote_id);
1461 }
1462 chan_mark_dead(c);
1463 }
1464 packet_send();
1465 }
1466}
1467
30460aeb 1468/* ARGSUSED */
3c0ef626 1469static int
30460aeb 1470channel_handle_rfd(Channel *c, fd_set *readset, fd_set *writeset)
3c0ef626 1471{
473db5ab 1472 char buf[CHAN_RBUF];
fa0f0f45 1473 int len, force;
3c0ef626 1474
fa0f0f45 1475 force = c->isatty && c->detach_close && c->istate != CHAN_INPUT_CLOSED;
1476 if (c->rfd != -1 && (force || FD_ISSET(c->rfd, readset))) {
30460aeb 1477 errno = 0;
3c0ef626 1478 len = read(c->rfd, buf, sizeof(buf));
fa0f0f45 1479 if (len < 0 && (errno == EINTR || (errno == EAGAIN && !force)))
3c0ef626 1480 return 1;
30460aeb 1481#ifndef PTY_ZEROREAD
3c0ef626 1482 if (len <= 0) {
30460aeb 1483#else
1484 if ((!c->isatty && len <= 0) ||
1485 (c->isatty && (len < 0 || (len == 0 && errno != 0)))) {
1486#endif
473db5ab 1487 debug2("channel %d: read<=0 rfd %d len %d",
3c0ef626 1488 c->self, c->rfd, len);
1489 if (c->type != SSH_CHANNEL_OPEN) {
473db5ab 1490 debug2("channel %d: not open", c->self);
3c0ef626 1491 chan_mark_dead(c);
1492 return -1;
1493 } else if (compat13) {
473db5ab 1494 buffer_clear(&c->output);
3c0ef626 1495 c->type = SSH_CHANNEL_INPUT_DRAINING;
473db5ab 1496 debug2("channel %d: input draining.", c->self);
3c0ef626 1497 } else {
1498 chan_read_failed(c);
1499 }
1500 return -1;
1501 }
473db5ab 1502 if (c->input_filter != NULL) {
3c0ef626 1503 if (c->input_filter(c, buf, len) == -1) {
473db5ab 1504 debug2("channel %d: filter stops", c->self);
3c0ef626 1505 chan_read_failed(c);
1506 }
08822d99 1507 } else if (c->datagram) {
1508 buffer_put_string(&c->input, buf, len);
3c0ef626 1509 } else {
1510 buffer_append(&c->input, buf, len);
1511 }
1512 }
1513 return 1;
1514}
30460aeb 1515
1516/* ARGSUSED */
3c0ef626 1517static int
30460aeb 1518channel_handle_wfd(Channel *c, fd_set *readset, fd_set *writeset)
3c0ef626 1519{
1520 struct termios tio;
08822d99 1521 u_char *data = NULL, *buf;
3c0ef626 1522 u_int dlen;
1523 int len;
1524
1525 /* Send buffered output data to the socket. */
1526 if (c->wfd != -1 &&
1527 FD_ISSET(c->wfd, writeset) &&
1528 buffer_len(&c->output) > 0) {
08822d99 1529 if (c->output_filter != NULL) {
1530 if ((buf = c->output_filter(c, &data, &dlen)) == NULL) {
1531 debug2("channel %d: filter stops", c->self);
1532 if (c->type != SSH_CHANNEL_OPEN)
1533 chan_mark_dead(c);
1534 else
1535 chan_write_failed(c);
1536 return -1;
1537 }
1538 } else if (c->datagram) {
1539 buf = data = buffer_get_string(&c->output, &dlen);
1540 } else {
1541 buf = data = buffer_ptr(&c->output);
1542 dlen = buffer_len(&c->output);
1543 }
1544
1545 if (c->datagram) {
1546 /* ignore truncated writes, datagrams might get lost */
1547 c->local_consumed += dlen + 4;
1548 len = write(c->wfd, buf, dlen);
1549 xfree(data);
1550 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1551 return 1;
1552 if (len <= 0) {
1553 if (c->type != SSH_CHANNEL_OPEN)
1554 chan_mark_dead(c);
1555 else
1556 chan_write_failed(c);
1557 return -1;
1558 }
1559 return 1;
1560 }
473db5ab 1561#ifdef _AIX
1562 /* XXX: Later AIX versions can't push as much data to tty */
1563 if (compat20 && c->wfd_isatty)
1564 dlen = MIN(dlen, 8*1024);
1565#endif
08822d99 1566
1567 len = write(c->wfd, buf, dlen);
3c0ef626 1568 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1569 return 1;
1570 if (len <= 0) {
1571 if (c->type != SSH_CHANNEL_OPEN) {
473db5ab 1572 debug2("channel %d: not open", c->self);
3c0ef626 1573 chan_mark_dead(c);
1574 return -1;
1575 } else if (compat13) {
473db5ab 1576 buffer_clear(&c->output);
1577 debug2("channel %d: input draining.", c->self);
3c0ef626 1578 c->type = SSH_CHANNEL_INPUT_DRAINING;
1579 } else {
1580 chan_write_failed(c);
1581 }
1582 return -1;
1583 }
08822d99 1584 if (compat20 && c->isatty && dlen >= 1 && buf[0] != '\r') {
3c0ef626 1585 if (tcgetattr(c->wfd, &tio) == 0 &&
1586 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1587 /*
1588 * Simulate echo to reduce the impact of
1589 * traffic analysis. We need to match the
1590 * size of a SSH2_MSG_CHANNEL_DATA message
08822d99 1591 * (4 byte channel id + buf)
3c0ef626 1592 */
1593 packet_send_ignore(4 + len);
1594 packet_send();
1595 }
1596 }
1597 buffer_consume(&c->output, len);
1598 if (compat20 && len > 0) {
1599 c->local_consumed += len;
1600 }
1601 }
1602 return 1;
1603}
30460aeb 1604
3c0ef626 1605static int
30460aeb 1606channel_handle_efd(Channel *c, fd_set *readset, fd_set *writeset)
3c0ef626 1607{
473db5ab 1608 char buf[CHAN_RBUF];
3c0ef626 1609 int len;
1610
1611/** XXX handle drain efd, too */
1612 if (c->efd != -1) {
1613 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1614 FD_ISSET(c->efd, writeset) &&
1615 buffer_len(&c->extended) > 0) {
1616 len = write(c->efd, buffer_ptr(&c->extended),
1617 buffer_len(&c->extended));
1618 debug2("channel %d: written %d to efd %d",
1619 c->self, len, c->efd);
1620 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1621 return 1;
1622 if (len <= 0) {
1623 debug2("channel %d: closing write-efd %d",
1624 c->self, c->efd);
1625 channel_close_fd(&c->efd);
1626 } else {
1627 buffer_consume(&c->extended, len);
1628 c->local_consumed += len;
1629 }
1630 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
0b90ac93 1631 (c->detach_close || FD_ISSET(c->efd, readset))) {
3c0ef626 1632 len = read(c->efd, buf, sizeof(buf));
1633 debug2("channel %d: read %d from efd %d",
473db5ab 1634 c->self, len, c->efd);
0b90ac93 1635 if (len < 0 && (errno == EINTR ||
1636 (errno == EAGAIN && !c->detach_close)))
3c0ef626 1637 return 1;
1638 if (len <= 0) {
1639 debug2("channel %d: closing read-efd %d",
1640 c->self, c->efd);
1641 channel_close_fd(&c->efd);
1642 } else {
1643 buffer_append(&c->extended, buf, len);
1644 }
1645 }
1646 }
1647 return 1;
1648}
30460aeb 1649
1650/* ARGSUSED */
3c0ef626 1651static int
30460aeb 1652channel_handle_ctl(Channel *c, fd_set *readset, fd_set *writeset)
473db5ab 1653{
1654 char buf[16];
1655 int len;
1656
1657 /* Monitor control fd to detect if the slave client exits */
1658 if (c->ctl_fd != -1 && FD_ISSET(c->ctl_fd, readset)) {
1659 len = read(c->ctl_fd, buf, sizeof(buf));
1660 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1661 return 1;
1662 if (len <= 0) {
1663 debug2("channel %d: ctl read<=0", c->self);
1664 if (c->type != SSH_CHANNEL_OPEN) {
1665 debug2("channel %d: not open", c->self);
1666 chan_mark_dead(c);
1667 return -1;
1668 } else {
1669 chan_read_failed(c);
1670 chan_write_failed(c);
1671 }
1672 return -1;
1673 } else
1674 fatal("%s: unexpected data on ctl fd", __func__);
1675 }
1676 return 1;
1677}
30460aeb 1678
473db5ab 1679static int
3c0ef626 1680channel_check_window(Channel *c)
1681{
1682 if (c->type == SSH_CHANNEL_OPEN &&
1683 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
fa0f0f45 1684 ((c->local_window_max - c->local_window >
1685 c->local_maxpacket*3) ||
1686 c->local_window < c->local_window_max/2) &&
3c0ef626 1687 c->local_consumed > 0) {
a7213e65 1688 u_int addition = 0;
1689 /* adjust max window size if we are in a dynamic environment */
1690 if (c->dynamic_window && (c->tcpwinsz > c->local_window_max)) {
1691 addition = c->tcpwinsz - c->local_window_max;
473db5ab 1692 c->local_window_max += addition;
1693 }
3c0ef626 1694 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1695 packet_put_int(c->remote_id);
473db5ab 1696 packet_put_int(c->local_consumed + addition);
3c0ef626 1697 packet_send();
1698 debug2("channel %d: window %d sent adjust %d",
1699 c->self, c->local_window,
1700 c->local_consumed);
473db5ab 1701 c->local_window += c->local_consumed + addition;
3c0ef626 1702 c->local_consumed = 0;
1703 }
1704 return 1;
1705}
1706
1707static void
30460aeb 1708channel_post_open(Channel *c, fd_set *readset, fd_set *writeset)
3c0ef626 1709{
1710 if (c->delayed)
1711 return;
1712 channel_handle_rfd(c, readset, writeset);
1713 channel_handle_wfd(c, readset, writeset);
473db5ab 1714 if (!compat20)
3c0ef626 1715 return;
3c0ef626 1716 channel_handle_efd(c, readset, writeset);
473db5ab 1717 channel_handle_ctl(c, readset, writeset);
3c0ef626 1718 channel_check_window(c);
1719}
1720
30460aeb 1721/* ARGSUSED */
3c0ef626 1722static void
30460aeb 1723channel_post_output_drain_13(Channel *c, fd_set *readset, fd_set *writeset)
3c0ef626 1724{
1725 int len;
473db5ab 1726
3c0ef626 1727 /* Send buffered output data to the socket. */
1728 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1729 len = write(c->sock, buffer_ptr(&c->output),
1730 buffer_len(&c->output));
1731 if (len <= 0)
473db5ab 1732 buffer_clear(&c->output);
3c0ef626 1733 else
1734 buffer_consume(&c->output, len);
1735 }
1736}
1737
1738static void
1739channel_handler_init_20(void)
1740{
473db5ab 1741 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
3c0ef626 1742 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1743 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1744 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
1745 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1746 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1747 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1748 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1749
473db5ab 1750 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
3c0ef626 1751 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1752 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
1753 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1754 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1755 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
473db5ab 1756 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
3c0ef626 1757}
1758
1759static void
1760channel_handler_init_13(void)
1761{
1762 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
1763 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
1764 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1765 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1766 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1767 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
1768 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1769 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1770 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1771
473db5ab 1772 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
3c0ef626 1773 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1774 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1775 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1776 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
1777 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
473db5ab 1778 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
3c0ef626 1779}
1780
1781static void
1782channel_handler_init_15(void)
1783{
473db5ab 1784 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
3c0ef626 1785 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1786 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1787 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1788 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1789 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1790 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1791
1792 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1793 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1794 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
473db5ab 1795 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
3c0ef626 1796 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
473db5ab 1797 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
3c0ef626 1798}
1799
1800static void
1801channel_handler_init(void)
1802{
1803 int i;
473db5ab 1804
1805 for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
3c0ef626 1806 channel_pre[i] = NULL;
1807 channel_post[i] = NULL;
1808 }
1809 if (compat20)
1810 channel_handler_init_20();
1811 else if (compat13)
1812 channel_handler_init_13();
1813 else
1814 channel_handler_init_15();
1815}
1816
1817/* gc dead channels */
1818static void
1819channel_garbage_collect(Channel *c)
1820{
1821 if (c == NULL)
1822 return;
1823 if (c->detach_user != NULL) {
08822d99 1824 if (!chan_is_dead(c, c->detach_close))
3c0ef626 1825 return;
473db5ab 1826 debug2("channel %d: gc: notify user", c->self);
3c0ef626 1827 c->detach_user(c->self, NULL);
1828 /* if we still have a callback */
1829 if (c->detach_user != NULL)
1830 return;
473db5ab 1831 debug2("channel %d: gc: user detached", c->self);
3c0ef626 1832 }
1833 if (!chan_is_dead(c, 1))
1834 return;
473db5ab 1835 debug2("channel %d: garbage collecting", c->self);
3c0ef626 1836 channel_free(c);
1837}
1838
1839static void
30460aeb 1840channel_handler(chan_fn *ftab[], fd_set *readset, fd_set *writeset)
3c0ef626 1841{
1842 static int did_init = 0;
473db5ab 1843 u_int i;
3c0ef626 1844 Channel *c;
1845
1846 if (!did_init) {
1847 channel_handler_init();
1848 did_init = 1;
1849 }
1850 for (i = 0; i < channels_alloc; i++) {
1851 c = channels[i];
1852 if (c == NULL)
1853 continue;
1854 if (ftab[c->type] != NULL)
1855 (*ftab[c->type])(c, readset, writeset);
1856 channel_garbage_collect(c);
1857 }
1858}
1859
1860/*
1861 * Allocate/update select bitmasks and add any bits relevant to channels in
1862 * select bitmasks.
1863 */
1864void
1865channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
473db5ab 1866 u_int *nallocp, int rekeying)
3c0ef626 1867{
30460aeb 1868 u_int n, sz, nfdset;
3c0ef626 1869
1870 n = MAX(*maxfdp, channel_max_fd);
1871
30460aeb 1872 nfdset = howmany(n+1, NFDBITS);
1873 /* Explicitly test here, because xrealloc isn't always called */
1874 if (nfdset && SIZE_T_MAX / nfdset < sizeof(fd_mask))
1875 fatal("channel_prepare_select: max_fd (%d) is too large", n);
1876 sz = nfdset * sizeof(fd_mask);
1877
3c0ef626 1878 /* perhaps check sz < nalloc/2 and shrink? */
1879 if (*readsetp == NULL || sz > *nallocp) {
30460aeb 1880 *readsetp = xrealloc(*readsetp, nfdset, sizeof(fd_mask));
1881 *writesetp = xrealloc(*writesetp, nfdset, sizeof(fd_mask));
3c0ef626 1882 *nallocp = sz;
1883 }
1884 *maxfdp = n;
1885 memset(*readsetp, 0, sz);
1886 memset(*writesetp, 0, sz);
1887
1888 if (!rekeying)
1889 channel_handler(channel_pre, *readsetp, *writesetp);
1890}
1891
1892/*
1893 * After select, perform any appropriate operations for channels which have
1894 * events pending.
1895 */
1896void
30460aeb 1897channel_after_select(fd_set *readset, fd_set *writeset)
3c0ef626 1898{
1899 channel_handler(channel_post, readset, writeset);
1900}
1901
1902
1903/* If there is data to send to the connection, enqueue some of it now. */
3c0ef626 1904void
473db5ab 1905channel_output_poll(void)
3c0ef626 1906{
3c0ef626 1907 Channel *c;
473db5ab 1908 u_int i, len;
3c0ef626 1909
1910 for (i = 0; i < channels_alloc; i++) {
1911 c = channels[i];
1912 if (c == NULL)
1913 continue;
1914
1915 /*
1916 * We are only interested in channels that can have buffered
1917 * incoming data.
1918 */
1919 if (compat13) {
1920 if (c->type != SSH_CHANNEL_OPEN &&
1921 c->type != SSH_CHANNEL_INPUT_DRAINING)
1922 continue;
1923 } else {
1924 if (c->type != SSH_CHANNEL_OPEN)
1925 continue;
1926 }
1927 if (compat20 &&
1928 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
1929 /* XXX is this true? */
1930 debug3("channel %d: will not send data after close", c->self);
1931 continue;
1932 }
1933
1934 /* Get the amount of buffered data for this channel. */
1935 if ((c->istate == CHAN_INPUT_OPEN ||
1936 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
1937 (len = buffer_len(&c->input)) > 0) {
08822d99 1938 if (c->datagram) {
1939 if (len > 0) {
1940 u_char *data;
1941 u_int dlen;
1942
1943 data = buffer_get_string(&c->input,
1944 &dlen);
1945 packet_start(SSH2_MSG_CHANNEL_DATA);
1946 packet_put_int(c->remote_id);
1947 packet_put_string(data, dlen);
1948 packet_send();
1949 c->remote_window -= dlen + 4;
1950 xfree(data);
1951 }
1952 continue;
1953 }
3c0ef626 1954 /*
1955 * Send some data for the other side over the secure
1956 * connection.
1957 */
1958 if (compat20) {
1959 if (len > c->remote_window)
1960 len = c->remote_window;
1961 if (len > c->remote_maxpacket)
1962 len = c->remote_maxpacket;
1963 } else {
1964 if (packet_is_interactive()) {
1965 if (len > 1024)
1966 len = 512;
1967 } else {
1968 /* Keep the packets at reasonable size. */
1969 if (len > packet_get_maxsize()/2)
1970 len = packet_get_maxsize()/2;
1971 }
1972 }
1973 if (len > 0) {
1974 packet_start(compat20 ?
1975 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
1976 packet_put_int(c->remote_id);
1977 packet_put_string(buffer_ptr(&c->input), len);
1978 packet_send();
1979 buffer_consume(&c->input, len);
1980 c->remote_window -= len;
1981 }
1982 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1983 if (compat13)
1984 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
1985 /*
1986 * input-buffer is empty and read-socket shutdown:
473db5ab 1987 * tell peer, that we will not send more data: send IEOF.
1988 * hack for extended data: delay EOF if EFD still in use.
3c0ef626 1989 */
473db5ab 1990 if (CHANNEL_EFD_INPUT_ACTIVE(c))
1991 debug2("channel %d: ibuf_empty delayed efd %d/(%d)",
1992 c->self, c->efd, buffer_len(&c->extended));
1993 else
1994 chan_ibuf_empty(c);
3c0ef626 1995 }
1996 /* Send extended data, i.e. stderr */
1997 if (compat20 &&
473db5ab 1998 !(c->flags & CHAN_EOF_SENT) &&
3c0ef626 1999 c->remote_window > 0 &&
2000 (len = buffer_len(&c->extended)) > 0 &&
2001 c->extended_usage == CHAN_EXTENDED_READ) {
473db5ab 2002 debug2("channel %d: rwin %u elen %u euse %d",
3c0ef626 2003 c->self, c->remote_window, buffer_len(&c->extended),
2004 c->extended_usage);
2005 if (len > c->remote_window)
2006 len = c->remote_window;
2007 if (len > c->remote_maxpacket)
2008 len = c->remote_maxpacket;
2009 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
2010 packet_put_int(c->remote_id);
2011 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
2012 packet_put_string(buffer_ptr(&c->extended), len);
2013 packet_send();
2014 buffer_consume(&c->extended, len);
2015 c->remote_window -= len;
2016 debug2("channel %d: sent ext data %d", c->self, len);
2017 }
2018 }
2019}
2020
2021
2022/* -- protocol input */
2023
30460aeb 2024/* ARGSUSED */
3c0ef626 2025void
473db5ab 2026channel_input_data(int type, u_int32_t seq, void *ctxt)
3c0ef626 2027{
2028 int id;
2029 char *data;
2030 u_int data_len;
2031 Channel *c;
2032
2033 /* Get the channel number and verify it. */
2034 id = packet_get_int();
2035 c = channel_lookup(id);
2036 if (c == NULL)
2037 packet_disconnect("Received data for nonexistent channel %d.", id);
2038
2039 /* Ignore any data for non-open channels (might happen on close) */
2040 if (c->type != SSH_CHANNEL_OPEN &&
2041 c->type != SSH_CHANNEL_X11_OPEN)
2042 return;
2043
3c0ef626 2044 /* Get the data. */
2045 data = packet_get_string(&data_len);
3c0ef626 2046
473db5ab 2047 /*
2048 * Ignore data for protocol > 1.3 if output end is no longer open.
2049 * For protocol 2 the sending side is reducing its window as it sends
2050 * data, so we must 'fake' consumption of the data in order to ensure
2051 * that window updates are sent back. Otherwise the connection might
2052 * deadlock.
2053 */
2054 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) {
2055 if (compat20) {
2056 c->local_window -= data_len;
2057 c->local_consumed += data_len;
2058 }
2059 xfree(data);
2060 return;
2061 }
2062
2063 if (compat20) {
3c0ef626 2064 if (data_len > c->local_maxpacket) {
473db5ab 2065 logit("channel %d: rcvd big packet %d, maxpack %d",
3c0ef626 2066 c->self, data_len, c->local_maxpacket);
2067 }
2068 if (data_len > c->local_window) {
473db5ab 2069 logit("channel %d: rcvd too much data %d, win %d",
3c0ef626 2070 c->self, data_len, c->local_window);
2071 xfree(data);
2072 return;
2073 }
2074 c->local_window -= data_len;
3c0ef626 2075 }
473db5ab 2076 packet_check_eom();
08822d99 2077 if (c->datagram)
2078 buffer_put_string(&c->output, data, data_len);
2079 else
2080 buffer_append(&c->output, data, data_len);
3c0ef626 2081 xfree(data);
2082}
2083
30460aeb 2084/* ARGSUSED */
3c0ef626 2085void
473db5ab 2086channel_input_extended_data(int type, u_int32_t seq, void *ctxt)
3c0ef626 2087{
2088 int id;
3c0ef626 2089 char *data;
473db5ab 2090 u_int data_len, tcode;
3c0ef626 2091 Channel *c;
2092
2093 /* Get the channel number and verify it. */
2094 id = packet_get_int();
2095 c = channel_lookup(id);
2096
2097 if (c == NULL)
2098 packet_disconnect("Received extended_data for bad channel %d.", id);
2099 if (c->type != SSH_CHANNEL_OPEN) {
473db5ab 2100 logit("channel %d: ext data for non open", id);
3c0ef626 2101 return;
2102 }
473db5ab 2103 if (c->flags & CHAN_EOF_RCVD) {
2104 if (datafellows & SSH_BUG_EXTEOF)
2105 debug("channel %d: accepting ext data after eof", id);
2106 else
2107 packet_disconnect("Received extended_data after EOF "
2108 "on channel %d.", id);
2109 }
3c0ef626 2110 tcode = packet_get_int();
2111 if (c->efd == -1 ||
2112 c->extended_usage != CHAN_EXTENDED_WRITE ||
2113 tcode != SSH2_EXTENDED_DATA_STDERR) {
473db5ab 2114 logit("channel %d: bad ext data", c->self);
3c0ef626 2115 return;
2116 }
2117 data = packet_get_string(&data_len);
473db5ab 2118 packet_check_eom();
3c0ef626 2119 if (data_len > c->local_window) {
473db5ab 2120 logit("channel %d: rcvd too much extended_data %d, win %d",
3c0ef626 2121 c->self, data_len, c->local_window);
2122 xfree(data);
2123 return;
2124 }
2125 debug2("channel %d: rcvd ext data %d", c->self, data_len);
2126 c->local_window -= data_len;
2127 buffer_append(&c->extended, data, data_len);
2128 xfree(data);
2129}
2130
30460aeb 2131/* ARGSUSED */
3c0ef626 2132void
473db5ab 2133channel_input_ieof(int type, u_int32_t seq, void *ctxt)
3c0ef626 2134{
2135 int id;
2136 Channel *c;
2137
3c0ef626 2138 id = packet_get_int();
473db5ab 2139 packet_check_eom();
3c0ef626 2140 c = channel_lookup(id);
2141 if (c == NULL)
2142 packet_disconnect("Received ieof for nonexistent channel %d.", id);
2143 chan_rcvd_ieof(c);
2144
2145 /* XXX force input close */
473db5ab 2146 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) {
3c0ef626 2147 debug("channel %d: FORCE input drain", c->self);
2148 c->istate = CHAN_INPUT_WAIT_DRAIN;
473db5ab 2149 if (buffer_len(&c->input) == 0)
2150 chan_ibuf_empty(c);
3c0ef626 2151 }
2152
2153}
2154
30460aeb 2155/* ARGSUSED */
3c0ef626 2156void
473db5ab 2157channel_input_close(int type, u_int32_t seq, void *ctxt)
3c0ef626 2158{
2159 int id;
2160 Channel *c;
2161
3c0ef626 2162 id = packet_get_int();
473db5ab 2163 packet_check_eom();
3c0ef626 2164 c = channel_lookup(id);
2165 if (c == NULL)
2166 packet_disconnect("Received close for nonexistent channel %d.", id);
2167
2168 /*
2169 * Send a confirmation that we have closed the channel and no more
2170 * data is coming for it.
2171 */
2172 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
2173 packet_put_int(c->remote_id);
2174 packet_send();
2175
2176 /*
2177 * If the channel is in closed state, we have sent a close request,
2178 * and the other side will eventually respond with a confirmation.
2179 * Thus, we cannot free the channel here, because then there would be
2180 * no-one to receive the confirmation. The channel gets freed when
2181 * the confirmation arrives.
2182 */
2183 if (c->type != SSH_CHANNEL_CLOSED) {
2184 /*
2185 * Not a closed channel - mark it as draining, which will
2186 * cause it to be freed later.
2187 */
473db5ab 2188 buffer_clear(&c->input);
3c0ef626 2189 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
2190 }
2191}
2192
2193/* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
30460aeb 2194/* ARGSUSED */
3c0ef626 2195void
473db5ab 2196channel_input_oclose(int type, u_int32_t seq, void *ctxt)
3c0ef626 2197{
2198 int id = packet_get_int();
2199 Channel *c = channel_lookup(id);
473db5ab 2200
2201 packet_check_eom();
3c0ef626 2202 if (c == NULL)
2203 packet_disconnect("Received oclose for nonexistent channel %d.", id);
2204 chan_rcvd_oclose(c);
2205}
2206
30460aeb 2207/* ARGSUSED */
3c0ef626 2208void
473db5ab 2209channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt)
3c0ef626 2210{
2211 int id = packet_get_int();
2212 Channel *c = channel_lookup(id);
2213
473db5ab 2214 packet_check_eom();
3c0ef626 2215 if (c == NULL)
2216 packet_disconnect("Received close confirmation for "
2217 "out-of-range channel %d.", id);
2218 if (c->type != SSH_CHANNEL_CLOSED)
2219 packet_disconnect("Received close confirmation for "
2220 "non-closed channel %d (type %d).", id, c->type);
2221 channel_free(c);
2222}
2223
30460aeb 2224/* ARGSUSED */
3c0ef626 2225void
473db5ab 2226channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt)
3c0ef626 2227{
2228 int id, remote_id;
2229 Channel *c;
2230
3c0ef626 2231 id = packet_get_int();
2232 c = channel_lookup(id);
2233
2234 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2235 packet_disconnect("Received open confirmation for "
2236 "non-opening channel %d.", id);
2237 remote_id = packet_get_int();
2238 /* Record the remote channel number and mark that the channel is now open. */
2239 c->remote_id = remote_id;
2240 c->type = SSH_CHANNEL_OPEN;
2241
2242 if (compat20) {
2243 c->remote_window = packet_get_int();
2244 c->remote_maxpacket = packet_get_int();
473db5ab 2245 if (c->confirm) {
3c0ef626 2246 debug2("callback start");
473db5ab 2247 c->confirm(c->self, c->confirm_ctx);
3c0ef626 2248 debug2("callback done");
2249 }
473db5ab 2250 debug2("channel %d: open confirm rwindow %u rmax %u", c->self,
3c0ef626 2251 c->remote_window, c->remote_maxpacket);
2252 }
473db5ab 2253 packet_check_eom();
3c0ef626 2254}
2255
2256static char *
2257reason2txt(int reason)
2258{
473db5ab 2259 switch (reason) {
3c0ef626 2260 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
2261 return "administratively prohibited";
2262 case SSH2_OPEN_CONNECT_FAILED:
2263 return "connect failed";
2264 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
2265 return "unknown channel type";
2266 case SSH2_OPEN_RESOURCE_SHORTAGE:
2267 return "resource shortage";
2268 }
2269 return "unknown reason";
2270}
2271
30460aeb 2272/* ARGSUSED */
3c0ef626 2273void
473db5ab 2274channel_input_open_failure(int type, u_int32_t seq, void *ctxt)
3c0ef626 2275{
2276 int id, reason;
2277 char *msg = NULL, *lang = NULL;
2278 Channel *c;
2279
3c0ef626 2280 id = packet_get_int();
2281 c = channel_lookup(id);
2282
2283 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2284 packet_disconnect("Received open failure for "
2285 "non-opening channel %d.", id);
2286 if (compat20) {
2287 reason = packet_get_int();
2288 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
2289 msg = packet_get_string(NULL);
2290 lang = packet_get_string(NULL);
2291 }
473db5ab 2292 logit("channel %d: open failed: %s%s%s", id,
3c0ef626 2293 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
2294 if (msg != NULL)
2295 xfree(msg);
2296 if (lang != NULL)
2297 xfree(lang);
2298 }
473db5ab 2299 packet_check_eom();
3c0ef626 2300 /* Free the channel. This will also close the socket. */
2301 channel_free(c);
2302}
2303
30460aeb 2304/* ARGSUSED */
3c0ef626 2305void
473db5ab 2306channel_input_window_adjust(int type, u_int32_t seq, void *ctxt)
3c0ef626 2307{
3c0ef626 2308 Channel *c;
473db5ab 2309 int id;
2310 u_int adjust;
3c0ef626 2311
2312 if (!compat20)
2313 return;
2314
2315 /* Get the channel number and verify it. */
2316 id = packet_get_int();
2317 c = channel_lookup(id);
2318
08822d99 2319 if (c == NULL) {
2320 logit("Received window adjust for non-open channel %d.", id);
3c0ef626 2321 return;
2322 }
2323 adjust = packet_get_int();
473db5ab 2324 packet_check_eom();
2325 debug2("channel %d: rcvd adjust %u", id, adjust);
3c0ef626 2326 c->remote_window += adjust;
2327}
2328
30460aeb 2329/* ARGSUSED */
3c0ef626 2330void
473db5ab 2331channel_input_port_open(int type, u_int32_t seq, void *ctxt)
3c0ef626 2332{
2333 Channel *c = NULL;
2334 u_short host_port;
2335 char *host, *originator_string;
2336 int remote_id, sock = -1;
2337
2338 remote_id = packet_get_int();
2339 host = packet_get_string(NULL);
2340 host_port = packet_get_int();
2341
2342 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2343 originator_string = packet_get_string(NULL);
2344 } else {
2345 originator_string = xstrdup("unknown (remote did not supply name)");
2346 }
473db5ab 2347 packet_check_eom();
3c0ef626 2348 sock = channel_connect_to(host, host_port);
2349 if (sock != -1) {
2350 c = channel_new("connected socket",
2351 SSH_CHANNEL_CONNECTING, sock, sock, -1, 0, 0, 0,
2352 originator_string, 1);
473db5ab 2353 c->remote_id = remote_id;
3c0ef626 2354 }
473db5ab 2355 xfree(originator_string);
3c0ef626 2356 if (c == NULL) {
2357 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2358 packet_put_int(remote_id);
2359 packet_send();
2360 }
2361 xfree(host);
2362}
2363
2364
2365/* -- tcp forwarding */
2366
2367void
2368channel_set_af(int af)
2369{
2370 IPv4or6 = af;
2371}
2372
473db5ab 2373static int
2374channel_setup_fwd_listener(int type, const char *listen_addr, u_short listen_port,
a7213e65 2375 const char *host_to_connect, u_short port_to_connect, int gateway_ports,
2376 int hpn_disabled, int hpn_buffer_size)
3c0ef626 2377{
2378 Channel *c;
08822d99 2379 int sock, r, success = 0, wildcard = 0, is_client;
3c0ef626 2380 struct addrinfo hints, *ai, *aitop;
473db5ab 2381 const char *host, *addr;
3c0ef626 2382 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
3c0ef626 2383
473db5ab 2384 host = (type == SSH_CHANNEL_RPORT_LISTENER) ?
2385 listen_addr : host_to_connect;
2386 is_client = (type == SSH_CHANNEL_PORT_LISTENER);
3c0ef626 2387
473db5ab 2388 if (host == NULL) {
2389 error("No forward host name.");
2390 return 0;
3c0ef626 2391 }
3c0ef626 2392 if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) {
2393 error("Forward host name too long.");
473db5ab 2394 return 0;
3c0ef626 2395 }
2396
473db5ab 2397 /*
2398 * Determine whether or not a port forward listens to loopback,
2399 * specified address or wildcard. On the client, a specified bind
2400 * address will always override gateway_ports. On the server, a
2401 * gateway_ports of 1 (``yes'') will override the client's
2402 * specification and force a wildcard bind, whereas a value of 2
2403 * (``clientspecified'') will bind to whatever address the client
2404 * asked for.
2405 *
2406 * Special-case listen_addrs are:
2407 *
2408 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR
2409 * "" (empty string), "*" -> wildcard v4/v6
2410 * "localhost" -> loopback v4/v6
2411 */
2412 addr = NULL;
2413 if (listen_addr == NULL) {
2414 /* No address specified: default to gateway_ports setting */
2415 if (gateway_ports)
2416 wildcard = 1;
2417 } else if (gateway_ports || is_client) {
2418 if (((datafellows & SSH_OLD_FORWARD_ADDR) &&
2419 strcmp(listen_addr, "0.0.0.0") == 0) ||
2420 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 ||
2421 (!is_client && gateway_ports == 1))
2422 wildcard = 1;
2423 else if (strcmp(listen_addr, "localhost") != 0)
2424 addr = listen_addr;
2425 }
2426
2427 debug3("channel_setup_fwd_listener: type %d wildcard %d addr %s",
2428 type, wildcard, (addr == NULL) ? "NULL" : addr);
2429
3c0ef626 2430 /*
2431 * getaddrinfo returns a loopback address if the hostname is
2432 * set to NULL and hints.ai_flags is not AI_PASSIVE
2433 */
2434 memset(&hints, 0, sizeof(hints));
2435 hints.ai_family = IPv4or6;
473db5ab 2436 hints.ai_flags = wildcard ? AI_PASSIVE : 0;
3c0ef626 2437 hints.ai_socktype = SOCK_STREAM;
2438 snprintf(strport, sizeof strport, "%d", listen_port);
473db5ab 2439 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) {
2440 if (addr == NULL) {
2441 /* This really shouldn't happen */
2442 packet_disconnect("getaddrinfo: fatal error: %s",
2443 gai_strerror(r));
2444 } else {
2445 error("channel_setup_fwd_listener: "
2446 "getaddrinfo(%.64s): %s", addr, gai_strerror(r));
2447 }
2448 return 0;
2449 }
3c0ef626 2450
2451 for (ai = aitop; ai; ai = ai->ai_next) {
2452 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2453 continue;
2454 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2455 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
473db5ab 2456 error("channel_setup_fwd_listener: getnameinfo failed");
3c0ef626 2457 continue;
2458 }
2459 /* Create a port to listen for the host. */
473db5ab 2460 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
3c0ef626 2461 if (sock < 0) {
2462 /* this is no error since kernel may not support ipv6 */
2463 verbose("socket: %.100s", strerror(errno));
2464 continue;
2465 }
08822d99 2466
2467 channel_set_reuseaddr(sock);
473db5ab 2468
3c0ef626 2469 debug("Local forwarding listening on %s port %s.", ntop, strport);
2470
2471 /* Bind the socket to the address. */
2472 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2473 /* address can be in use ipv6 address is already bound */
2474 if (!ai->ai_next)
2475 error("bind: %.100s", strerror(errno));
2476 else
2477 verbose("bind: %.100s", strerror(errno));
2478
2479 close(sock);
2480 continue;
2481 }
2482 /* Start listening for connections on the socket. */
473db5ab 2483 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
3c0ef626 2484 error("listen: %.100s", strerror(errno));
2485 close(sock);
2486 continue;
2487 }
2488 /* Allocate a channel number for the socket. */
a7213e65 2489 /* explicitly test for hpn disabled option. if true use smaller window size */
2490 if (hpn_disabled)
2491 c = channel_new("port listener", type, sock, sock, -1,
2492 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2493 0, "port listener", 1);
2494 else
2495 c = channel_new("port listener", type, sock, sock, -1,
2496 hpn_buffer_size, CHAN_TCP_PACKET_DEFAULT,
2497 0, "port listener", 1);
3c0ef626 2498 strlcpy(c->path, host, sizeof(c->path));
2499 c->host_port = port_to_connect;
2500 c->listening_port = listen_port;
2501 success = 1;
2502 }
2503 if (success == 0)
473db5ab 2504 error("channel_setup_fwd_listener: cannot listen to port: %d",
3c0ef626 2505 listen_port);
2506 freeaddrinfo(aitop);
2507 return success;
2508}
2509
473db5ab 2510int
2511channel_cancel_rport_listener(const char *host, u_short port)
2512{
2513 u_int i;
2514 int found = 0;
2515
2516 for (i = 0; i < channels_alloc; i++) {
2517 Channel *c = channels[i];
2518
2519 if (c != NULL && c->type == SSH_CHANNEL_RPORT_LISTENER &&
2520 strncmp(c->path, host, sizeof(c->path)) == 0 &&
2521 c->listening_port == port) {
2522 debug2("%s: close channel %d", __func__, i);
2523 channel_free(c);
2524 found = 1;
2525 }
2526 }
2527
2528 return (found);
2529}
2530
2531/* protocol local port fwd, used by ssh (and sshd in v1) */
2532int
2533channel_setup_local_fwd_listener(const char *listen_host, u_short listen_port,
a7213e65 2534 const char *host_to_connect, u_short port_to_connect, int gateway_ports,
2535 int hpn_disabled, int hpn_buffer_size)
473db5ab 2536{
2537 return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER,
2538 listen_host, listen_port, host_to_connect, port_to_connect,
a7213e65 2539 gateway_ports, hpn_disabled, hpn_buffer_size);
473db5ab 2540}
2541
2542/* protocol v2 remote port fwd, used by sshd */
2543int
2544channel_setup_remote_fwd_listener(const char *listen_address,
a7213e65 2545 u_short listen_port, int gateway_ports, int hpn_disabled, int hpn_buffer_size)
473db5ab 2546{
2547 return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER,
a7213e65 2548 listen_address, listen_port, NULL, 0, gateway_ports,
2549 hpn_disabled, hpn_buffer_size);
473db5ab 2550}
2551
3c0ef626 2552/*
2553 * Initiate forwarding of connections to port "port" on remote host through
2554 * the secure channel to host:port from local side.
2555 */
2556
30460aeb 2557int
473db5ab 2558channel_request_remote_forwarding(const char *listen_host, u_short listen_port,
3c0ef626 2559 const char *host_to_connect, u_short port_to_connect)
2560{
473db5ab 2561 int type, success = 0;
3c0ef626 2562
2563 /* Record locally that connection to this host/port is permitted. */
2564 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2565 fatal("channel_request_remote_forwarding: too many forwards");
2566
2567 /* Send the forward request to the remote side. */
2568 if (compat20) {
473db5ab 2569 const char *address_to_bind;
0b90ac93 2570 if (listen_host == NULL) {
2571 if (datafellows & SSH_BUG_RFWD_ADDR)
2572 address_to_bind = "127.0.0.1";
2573 else
2574 address_to_bind = "localhost";
2575 } else if (*listen_host == '\0' ||
2576 strcmp(listen_host, "*") == 0) {
2577 if (datafellows & SSH_BUG_RFWD_ADDR)
2578 address_to_bind = "0.0.0.0";
2579 else
2580 address_to_bind = "";
2581 } else
473db5ab 2582 address_to_bind = listen_host;
2583
3c0ef626 2584 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2585 packet_put_cstring("tcpip-forward");
473db5ab 2586 packet_put_char(1); /* boolean: want reply */
3c0ef626 2587 packet_put_cstring(address_to_bind);
2588 packet_put_int(listen_port);
2589 packet_send();
2590 packet_write_wait();
2591 /* Assume that server accepts the request */
2592 success = 1;
2593 } else {
2594 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2595 packet_put_int(listen_port);
2596 packet_put_cstring(host_to_connect);
2597 packet_put_int(port_to_connect);
2598 packet_send();
2599 packet_write_wait();
2600
2601 /* Wait for response from the remote side. */
473db5ab 2602 type = packet_read();
3c0ef626 2603 switch (type) {
2604 case SSH_SMSG_SUCCESS:
2605 success = 1;
2606 break;
2607 case SSH_SMSG_FAILURE:
3c0ef626 2608 break;
2609 default:
2610 /* Unknown packet */
2611 packet_disconnect("Protocol error for port forward request:"
2612 "received packet type %d.", type);
2613 }
2614 }
2615 if (success) {
2616 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2617 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2618 permitted_opens[num_permitted_opens].listen_port = listen_port;
2619 num_permitted_opens++;
2620 }
30460aeb 2621 return (success ? 0 : -1);
3c0ef626 2622}
2623
473db5ab 2624/*
2625 * Request cancellation of remote forwarding of connection host:port from
2626 * local side.
2627 */
2628void
2629channel_request_rforward_cancel(const char *host, u_short port)
2630{
2631 int i;
2632
2633 if (!compat20)
2634 return;
2635
2636 for (i = 0; i < num_permitted_opens; i++) {
2637 if (permitted_opens[i].host_to_connect != NULL &&
2638 permitted_opens[i].listen_port == port)
2639 break;
2640 }
2641 if (i >= num_permitted_opens) {
2642 debug("%s: requested forward not found", __func__);
2643 return;
2644 }
2645 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2646 packet_put_cstring("cancel-tcpip-forward");
2647 packet_put_char(0);
2648 packet_put_cstring(host == NULL ? "" : host);
2649 packet_put_int(port);
2650 packet_send();
2651
2652 permitted_opens[i].listen_port = 0;
2653 permitted_opens[i].port_to_connect = 0;
08822d99 2654 xfree(permitted_opens[i].host_to_connect);
473db5ab 2655 permitted_opens[i].host_to_connect = NULL;
2656}
2657
3c0ef626 2658/*
2659 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
2660 * listening for the port, and sends back a success reply (or disconnect
30460aeb 2661 * message if there was an error).
3c0ef626 2662 */
30460aeb 2663int
255d7550 2664channel_input_port_forward_request(int is_root, int gateway_ports,
f713db99 2665 int hpn_disabled, int hpn_buffer_size)
3c0ef626 2666{
2667 u_short port, host_port;
30460aeb 2668 int success = 0;
3c0ef626 2669 char *hostname;
2670
2671 /* Get arguments from the packet. */
2672 port = packet_get_int();
2673 hostname = packet_get_string(NULL);
2674 host_port = packet_get_int();
2675
2676#ifndef HAVE_CYGWIN
2677 /*
2678 * Check that an unprivileged user is not trying to forward a
2679 * privileged port.
2680 */
2681 if (port < IPPORT_RESERVED && !is_root)
473db5ab 2682 packet_disconnect(
2683 "Requested forwarding of port %d but user is not root.",
2684 port);
2685 if (host_port == 0)
2686 packet_disconnect("Dynamic forwarding denied.");
3c0ef626 2687#endif
473db5ab 2688
3c0ef626 2689 /* Initiate forwarding */
30460aeb 2690 success = channel_setup_local_fwd_listener(NULL, port, hostname,
a7213e65 2691 host_port, gateway_ports, hpn_disabled, hpn_buffer_size);
3c0ef626 2692
2693 /* Free the argument string. */
2694 xfree(hostname);
30460aeb 2695
2696 return (success ? 0 : -1);
3c0ef626 2697}
2698
2699/*
2700 * Permits opening to any host/port if permitted_opens[] is empty. This is
2701 * usually called by the server, because the user could connect to any port
2702 * anyway, and the server has no way to know but to trust the client anyway.
2703 */
2704void
473db5ab 2705channel_permit_all_opens(void)
3c0ef626 2706{
2707 if (num_permitted_opens == 0)
2708 all_opens_permitted = 1;
2709}
2710
2711void
2712channel_add_permitted_opens(char *host, int port)
2713{
2714 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
30460aeb 2715 fatal("channel_add_permitted_opens: too many forwards");
3c0ef626 2716 debug("allow port forwarding to host %s port %d", host, port);
2717
2718 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
2719 permitted_opens[num_permitted_opens].port_to_connect = port;
2720 num_permitted_opens++;
2721
2722 all_opens_permitted = 0;
2723}
2724
30460aeb 2725int
2726channel_add_adm_permitted_opens(char *host, int port)
2727{
2728 if (num_adm_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2729 fatal("channel_add_adm_permitted_opens: too many forwards");
2730 debug("config allows port forwarding to host %s port %d", host, port);
2731
2732 permitted_adm_opens[num_adm_permitted_opens].host_to_connect
2733 = xstrdup(host);
2734 permitted_adm_opens[num_adm_permitted_opens].port_to_connect = port;
2735 return ++num_adm_permitted_opens;
2736}
2737
3c0ef626 2738void
2739channel_clear_permitted_opens(void)
2740{
2741 int i;
2742
2743 for (i = 0; i < num_permitted_opens; i++)
473db5ab 2744 if (permitted_opens[i].host_to_connect != NULL)
2745 xfree(permitted_opens[i].host_to_connect);
3c0ef626 2746 num_permitted_opens = 0;
3c0ef626 2747}
2748
30460aeb 2749void
2750channel_clear_adm_permitted_opens(void)
2751{
2752 int i;
2753
2754 for (i = 0; i < num_adm_permitted_opens; i++)
2755 if (permitted_adm_opens[i].host_to_connect != NULL)
2756 xfree(permitted_adm_opens[i].host_to_connect);
2757 num_adm_permitted_opens = 0;
2758}
3c0ef626 2759
2760/* return socket to remote host, port */
2761static int
2762connect_to(const char *host, u_short port)
2763{
2764 struct addrinfo hints, *ai, *aitop;
2765 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2766 int gaierr;
2767 int sock = -1;
2768
2769 memset(&hints, 0, sizeof(hints));
2770 hints.ai_family = IPv4or6;
2771 hints.ai_socktype = SOCK_STREAM;
2772 snprintf(strport, sizeof strport, "%d", port);
2773 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
2774 error("connect_to %.100s: unknown host (%s)", host,
2775 gai_strerror(gaierr));
2776 return -1;
2777 }
2778 for (ai = aitop; ai; ai = ai->ai_next) {
2779 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2780 continue;
2781 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2782 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2783 error("connect_to: getnameinfo failed");
2784 continue;
2785 }
473db5ab 2786 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
3c0ef626 2787 if (sock < 0) {
473db5ab 2788 if (ai->ai_next == NULL)
2789 error("socket: %.100s", strerror(errno));
2790 else
2791 verbose("socket: %.100s", strerror(errno));
3c0ef626 2792 continue;
2793 }
473db5ab 2794 if (set_nonblock(sock) == -1)
2795 fatal("%s: set_nonblock(%d)", __func__, sock);
3c0ef626 2796 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 &&
2797 errno != EINPROGRESS) {
2798 error("connect_to %.100s port %s: %.100s", ntop, strport,
2799 strerror(errno));
2800 close(sock);
2801 continue; /* fail -- try next */
2802 }
2803 break; /* success */
2804
2805 }
2806 freeaddrinfo(aitop);
2807 if (!ai) {
2808 error("connect_to %.100s port %d: failed.", host, port);
2809 return -1;
2810 }
2811 /* success */
473db5ab 2812 set_nodelay(sock);
3c0ef626 2813 return sock;
2814}
2815
2816int
2817channel_connect_by_listen_address(u_short listen_port)
2818{
2819 int i;
2820
2821 for (i = 0; i < num_permitted_opens; i++)
473db5ab 2822 if (permitted_opens[i].host_to_connect != NULL &&
2823 permitted_opens[i].listen_port == listen_port)
3c0ef626 2824 return connect_to(
2825 permitted_opens[i].host_to_connect,
2826 permitted_opens[i].port_to_connect);
2827 error("WARNING: Server requests forwarding for unknown listen_port %d",
2828 listen_port);
2829 return -1;
2830}
2831
2832/* Check if connecting to that port is permitted and connect. */
2833int
2834channel_connect_to(const char *host, u_short port)
2835{
30460aeb 2836 int i, permit, permit_adm = 1;
3c0ef626 2837
2838 permit = all_opens_permitted;
2839 if (!permit) {
2840 for (i = 0; i < num_permitted_opens; i++)
473db5ab 2841 if (permitted_opens[i].host_to_connect != NULL &&
2842 permitted_opens[i].port_to_connect == port &&
3c0ef626 2843 strcmp(permitted_opens[i].host_to_connect, host) == 0)
2844 permit = 1;
30460aeb 2845 }
3c0ef626 2846
30460aeb 2847 if (num_adm_permitted_opens > 0) {
2848 permit_adm = 0;
2849 for (i = 0; i < num_adm_permitted_opens; i++)
2850 if (permitted_adm_opens[i].host_to_connect != NULL &&
2851 permitted_adm_opens[i].port_to_connect == port &&
2852 strcmp(permitted_adm_opens[i].host_to_connect, host)
2853 == 0)
2854 permit_adm = 1;
3c0ef626 2855 }
30460aeb 2856
2857 if (!permit || !permit_adm) {
473db5ab 2858 logit("Received request to connect to host %.100s port %d, "
3c0ef626 2859 "but the request was denied.", host, port);
2860 return -1;
2861 }
2862 return connect_to(host, port);
2863}
2864
473db5ab 2865void
2866channel_send_window_changes(void)
2867{
2868 u_int i;
2869 struct winsize ws;
2870
2871 for (i = 0; i < channels_alloc; i++) {
2872 if (channels[i] == NULL || !channels[i]->client_tty ||
2873 channels[i]->type != SSH_CHANNEL_OPEN)
2874 continue;
2875 if (ioctl(channels[i]->rfd, TIOCGWINSZ, &ws) < 0)
2876 continue;
2877 channel_request_start(i, "window-change", 0);
30460aeb 2878 packet_put_int((u_int)ws.ws_col);
2879 packet_put_int((u_int)ws.ws_row);
2880 packet_put_int((u_int)ws.ws_xpixel);
2881 packet_put_int((u_int)ws.ws_ypixel);
473db5ab 2882 packet_send();
2883 }
2884}
2885
3c0ef626 2886/* -- X11 forwarding */
2887
2888/*
2889 * Creates an internet domain socket for listening for X11 connections.
473db5ab 2890 * Returns 0 and a suitable display number for the DISPLAY variable
2891 * stored in display_numberp , or -1 if an error occurs.
3c0ef626 2892 */
473db5ab 2893int
2894x11_create_display_inet(int x11_display_offset, int x11_use_localhost,
a7213e65 2895 int single_connection, u_int *display_numberp, int **chanids,
2896 int hpn_disabled, int hpn_buffer_size)
3c0ef626 2897{
473db5ab 2898 Channel *nc = NULL;
3c0ef626 2899 int display_number, sock;
2900 u_short port;
2901 struct addrinfo hints, *ai, *aitop;
2902 char strport[NI_MAXSERV];
2903 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
3c0ef626 2904
08822d99 2905 if (chanids == NULL)
2906 return -1;
2907
3c0ef626 2908 for (display_number = x11_display_offset;
473db5ab 2909 display_number < MAX_DISPLAYS;
2910 display_number++) {
3c0ef626 2911 port = 6000 + display_number;
2912 memset(&hints, 0, sizeof(hints));
2913 hints.ai_family = IPv4or6;
473db5ab 2914 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE;
3c0ef626 2915 hints.ai_socktype = SOCK_STREAM;
2916 snprintf(strport, sizeof strport, "%d", port);
2917 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
2918 error("getaddrinfo: %.100s", gai_strerror(gaierr));
473db5ab 2919 return -1;
3c0ef626 2920 }
2921 for (ai = aitop; ai; ai = ai->ai_next) {
2922 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2923 continue;
473db5ab 2924 sock = socket(ai->ai_family, ai->ai_socktype,
2925 ai->ai_protocol);
3c0ef626 2926 if (sock < 0) {
2927 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
2928 error("socket: %.100s", strerror(errno));
473db5ab 2929 freeaddrinfo(aitop);
2930 return -1;
3c0ef626 2931 } else {
2932 debug("x11_create_display_inet: Socket family %d not supported",
2933 ai->ai_family);
2934 continue;
2935 }
2936 }
473db5ab 2937#ifdef IPV6_V6ONLY
2938 if (ai->ai_family == AF_INET6) {
2939 int on = 1;
2940 if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) < 0)
2941 error("setsockopt IPV6_V6ONLY: %.100s", strerror(errno));
2942 }
2943#endif
08822d99 2944 channel_set_reuseaddr(sock);
3c0ef626 2945 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
473db5ab 2946 debug2("bind port %d: %.100s", port, strerror(errno));
3c0ef626 2947 close(sock);
2948
2949 if (ai->ai_next)
2950 continue;
2951
2952 for (n = 0; n < num_socks; n++) {
3c0ef626 2953 close(socks[n]);
2954 }
2955 num_socks = 0;
2956 break;
2957 }
2958 socks[num_socks++] = sock;
2959#ifndef DONT_TRY_OTHER_AF
2960 if (num_socks == NUM_SOCKS)
2961 break;
2962#else
473db5ab 2963 if (x11_use_localhost) {
2964 if (num_socks == NUM_SOCKS)
2965 break;
2966 } else {
2967 break;
2968 }
3c0ef626 2969#endif
2970 }
2971 freeaddrinfo(aitop);
2972 if (num_socks > 0)
2973 break;
2974 }
2975 if (display_number >= MAX_DISPLAYS) {
2976 error("Failed to allocate internet-domain X11 display socket.");
473db5ab 2977 return -1;
3c0ef626 2978 }
2979 /* Start listening for connections on the socket. */
2980 for (n = 0; n < num_socks; n++) {
2981 sock = socks[n];
473db5ab 2982 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
3c0ef626 2983 error("listen: %.100s", strerror(errno));
3c0ef626 2984 close(sock);
473db5ab 2985 return -1;
3c0ef626 2986 }
3c0ef626 2987 }
3c0ef626 2988
2989 /* Allocate a channel for each socket. */
30460aeb 2990 *chanids = xcalloc(num_socks + 1, sizeof(**chanids));
3c0ef626 2991 for (n = 0; n < num_socks; n++) {
2992 sock = socks[n];
a7213e65 2993 if (hpn_disabled)
2994 nc = channel_new("x11 listener",
2995 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
2996 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2997 0, "X11 inet listener", 1);
2998 else
2999 nc = channel_new("x11 listener",
3000 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
3001 hpn_buffer_size, CHAN_X11_PACKET_DEFAULT,
3002 0, "X11 inet listener", 1);
473db5ab 3003 nc->single_connection = single_connection;
08822d99 3004 (*chanids)[n] = nc->self;
3c0ef626 3005 }
08822d99 3006 (*chanids)[n] = -1;
3c0ef626 3007
473db5ab 3008 /* Return the display number for the DISPLAY environment variable. */
3009 *display_numberp = display_number;
3010 return (0);
3c0ef626 3011}
3012
3c0ef626 3013static int
3014connect_local_xsocket(u_int dnr)
3015{
3c0ef626 3016 int sock;
3017 struct sockaddr_un addr;
3c0ef626 3018
473db5ab 3019 sock = socket(AF_UNIX, SOCK_STREAM, 0);
3020 if (sock < 0)
3021 error("socket: %.100s", strerror(errno));
3022 memset(&addr, 0, sizeof(addr));
3023 addr.sun_family = AF_UNIX;
3024 snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr);
30460aeb 3025 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0)
473db5ab 3026 return sock;
3027 close(sock);
3c0ef626 3028 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
3029 return -1;
3030}
3031
3032int
3033x11_connect_display(void)
3034{
30460aeb 3035 u_int display_number;
3c0ef626 3036 const char *display;
3037 char buf[1024], *cp;
3038 struct addrinfo hints, *ai, *aitop;
3039 char strport[NI_MAXSERV];
30460aeb 3040 int gaierr, sock = 0;
3c0ef626 3041
3042 /* Try to open a socket for the local X server. */
3043 display = getenv("DISPLAY");
3044 if (!display) {
3045 error("DISPLAY not set.");
3046 return -1;
3047 }
3048 /*
3049 * Now we decode the value of the DISPLAY variable and make a
3050 * connection to the real X server.
3051 */
3052
3053 /*
3054 * Check if it is a unix domain socket. Unix domain displays are in
3055 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
3056 */
3057 if (strncmp(display, "unix:", 5) == 0 ||
3058 display[0] == ':') {
3059 /* Connect to the unix domain socket. */
30460aeb 3060 if (sscanf(strrchr(display, ':') + 1, "%u", &display_number) != 1) {
3c0ef626 3061 error("Could not parse display number from DISPLAY: %.100s",
473db5ab 3062 display);
3c0ef626 3063 return -1;
3064 }
3065 /* Create a socket. */
3066 sock = connect_local_xsocket(display_number);
3067 if (sock < 0)
3068 return -1;
3069
3070 /* OK, we now have a connection to the display. */
3071 return sock;
3072 }
3073 /*
3074 * Connect to an inet socket. The DISPLAY value is supposedly
3075 * hostname:d[.s], where hostname may also be numeric IP address.
3076 */
473db5ab 3077 strlcpy(buf, display, sizeof(buf));
3c0ef626 3078 cp = strchr(buf, ':');
3079 if (!cp) {
3080 error("Could not find ':' in DISPLAY: %.100s", display);
3081 return -1;
3082 }
3083 *cp = 0;
3084 /* buf now contains the host name. But first we parse the display number. */
30460aeb 3085 if (sscanf(cp + 1, "%u", &display_number) != 1) {
3c0ef626 3086 error("Could not parse display number from DISPLAY: %.100s",
473db5ab 3087 display);
3c0ef626 3088 return -1;
3089 }
3090
3091 /* Look up the host address */
3092 memset(&hints, 0, sizeof(hints));
3093 hints.ai_family = IPv4or6;
3094 hints.ai_socktype = SOCK_STREAM;
30460aeb 3095 snprintf(strport, sizeof strport, "%u", 6000 + display_number);
3c0ef626 3096 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
3097 error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr));
3098 return -1;
3099 }
3100 for (ai = aitop; ai; ai = ai->ai_next) {
3101 /* Create a socket. */
473db5ab 3102 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
3c0ef626 3103 if (sock < 0) {
473db5ab 3104 debug2("socket: %.100s", strerror(errno));
3c0ef626 3105 continue;
3106 }
3107 /* Connect it to the display. */
3108 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
30460aeb 3109 debug2("connect %.100s port %u: %.100s", buf,
3c0ef626 3110 6000 + display_number, strerror(errno));
3111 close(sock);
3112 continue;
3113 }
3114 /* Success */
3115 break;
3116 }
3117 freeaddrinfo(aitop);
3118 if (!ai) {
30460aeb 3119 error("connect %.100s port %u: %.100s", buf, 6000 + display_number,
3c0ef626 3120 strerror(errno));
3121 return -1;
3122 }
473db5ab 3123 set_nodelay(sock);
3c0ef626 3124 return sock;
3125}
3126
3127/*
3128 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
3129 * the remote channel number. We should do whatever we want, and respond
3130 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
3131 */
3132
30460aeb 3133/* ARGSUSED */
3c0ef626 3134void
473db5ab 3135x11_input_open(int type, u_int32_t seq, void *ctxt)
3c0ef626 3136{
3137 Channel *c = NULL;
3138 int remote_id, sock = 0;
3139 char *remote_host;
3140
3141 debug("Received X11 open request.");
3142
3143 remote_id = packet_get_int();
3144
3145 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
3146 remote_host = packet_get_string(NULL);
3147 } else {
3148 remote_host = xstrdup("unknown (remote did not supply name)");
3149 }
473db5ab 3150 packet_check_eom();
3c0ef626 3151
3152 /* Obtain a connection to the real X display. */
3153 sock = x11_connect_display();
3154 if (sock != -1) {
3155 /* Allocate a channel for this connection. */
3156 c = channel_new("connected x11 socket",
3157 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
3158 remote_host, 1);
473db5ab 3159 c->remote_id = remote_id;
3160 c->force_drain = 1;
3c0ef626 3161 }
473db5ab 3162 xfree(remote_host);
3c0ef626 3163 if (c == NULL) {
3164 /* Send refusal to the remote host. */
3165 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3166 packet_put_int(remote_id);
3167 } else {
3168 /* Send a confirmation to the remote host. */
3169 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
3170 packet_put_int(remote_id);
3171 packet_put_int(c->self);
3172 }
3173 packet_send();
3174}
3175
3176/* dummy protocol handler that denies SSH-1 requests (agent/x11) */
30460aeb 3177/* ARGSUSED */
3c0ef626 3178void
473db5ab 3179deny_input_open(int type, u_int32_t seq, void *ctxt)
3c0ef626 3180{
3181 int rchan = packet_get_int();
473db5ab 3182
3183 switch (type) {
3c0ef626 3184 case SSH_SMSG_AGENT_OPEN:
3185 error("Warning: ssh server tried agent forwarding.");
3186 break;
3187 case SSH_SMSG_X11_OPEN:
3188 error("Warning: ssh server tried X11 forwarding.");
3189 break;
3190 default:
473db5ab 3191 error("deny_input_open: type %d", type);
3c0ef626 3192 break;
3193 }
08822d99 3194 error("Warning: this is probably a break-in attempt by a malicious server.");
3c0ef626 3195 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3196 packet_put_int(rchan);
3197 packet_send();
3198}
3199
3200/*
3201 * Requests forwarding of X11 connections, generates fake authentication
3202 * data, and enables authentication spoofing.
3203 * This should be called in the client only.
3204 */
3205void
473db5ab 3206x11_request_forwarding_with_spoofing(int client_session_id, const char *disp,
3c0ef626 3207 const char *proto, const char *data)
3208{
3209 u_int data_len = (u_int) strlen(data) / 2;
473db5ab 3210 u_int i, value;
3c0ef626 3211 char *new_data;
3212 int screen_number;
3213 const char *cp;
473db5ab 3214 u_int32_t rnd = 0;
3c0ef626 3215
473db5ab 3216 if (x11_saved_display == NULL)
3217 x11_saved_display = xstrdup(disp);
3218 else if (strcmp(disp, x11_saved_display) != 0) {
3219 error("x11_request_forwarding_with_spoofing: different "
3220 "$DISPLAY already forwarded");
3221 return;
3222 }
3223
30460aeb 3224 cp = strchr(disp, ':');
3c0ef626 3225 if (cp)
3226 cp = strchr(cp, '.');
3227 if (cp)
30460aeb 3228 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL);
3c0ef626 3229 else
3230 screen_number = 0;
3231
473db5ab 3232 if (x11_saved_proto == NULL) {
3233 /* Save protocol name. */
3234 x11_saved_proto = xstrdup(proto);
3235 /*
3236 * Extract real authentication data and generate fake data
3237 * of the same length.
3238 */
3239 x11_saved_data = xmalloc(data_len);
3240 x11_fake_data = xmalloc(data_len);
3241 for (i = 0; i < data_len; i++) {
3242 if (sscanf(data + 2 * i, "%2x", &value) != 1)
3243 fatal("x11_request_forwarding: bad "
3244 "authentication data: %.100s", data);
3245 if (i % 4 == 0)
3246 rnd = arc4random();
3247 x11_saved_data[i] = value;
3248 x11_fake_data[i] = rnd & 0xff;
3249 rnd >>= 8;
3250 }
3251 x11_saved_data_len = data_len;
3252 x11_fake_data_len = data_len;
3253 }
3c0ef626 3254
3255 /* Convert the fake data into hex. */
473db5ab 3256 new_data = tohex(x11_fake_data, data_len);
3c0ef626 3257
3258 /* Send the request packet. */
3259 if (compat20) {
3260 channel_request_start(client_session_id, "x11-req", 0);
3261 packet_put_char(0); /* XXX bool single connection */
3262 } else {
3263 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
3264 }
3265 packet_put_cstring(proto);
3266 packet_put_cstring(new_data);
3267 packet_put_int(screen_number);
3268 packet_send();
3269 packet_write_wait();
3270 xfree(new_data);
3271}
3272
3273
3274/* -- agent forwarding */
3275
3276/* Sends a message to the server to request authentication fd forwarding. */
3277
3278void
473db5ab 3279auth_request_forwarding(void)
3c0ef626 3280{
3281 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
3282 packet_send();
3283 packet_write_wait();
3284}
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