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3c0ef626 1/*
2 * Author: Tatu Ylonen <ylo@cs.hut.fi>
3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
4 * All rights reserved
5 * This file contains functions for generic socket connection forwarding.
6 * There is also code for initiating connection forwarding for X11 connections,
7 * arbitrary tcp/ip connections, and the authentication agent connection.
8 *
9 * As far as I am concerned, the code I have written for this software
10 * can be used freely for any purpose. Any derived versions of this
11 * software must be clearly marked as such, and if the derived work is
12 * incompatible with the protocol description in the RFC file, it must be
13 * called by a name other than "ssh" or "Secure Shell".
14 *
15 * SSH2 support added by Markus Friedl.
e9a17296 16 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved.
3c0ef626 17 * Copyright (c) 1999 Dug Song. All rights reserved.
18 * Copyright (c) 1999 Theo de Raadt. All rights reserved.
19 *
20 * Redistribution and use in source and binary forms, with or without
21 * modification, are permitted provided that the following conditions
22 * are met:
23 * 1. Redistributions of source code must retain the above copyright
24 * notice, this list of conditions and the following disclaimer.
25 * 2. Redistributions in binary form must reproduce the above copyright
26 * notice, this list of conditions and the following disclaimer in the
27 * documentation and/or other materials provided with the distribution.
28 *
29 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
30 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
31 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
32 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
33 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
34 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
35 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
36 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
37 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
38 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
39 */
40
41#include "includes.h"
dec6d9fe 42RCSID("$OpenBSD: channels.c,v 1.214 2005/03/14 11:46:56 markus Exp $");
3c0ef626 43
44#include "ssh.h"
45#include "ssh1.h"
46#include "ssh2.h"
47#include "packet.h"
48#include "xmalloc.h"
3c0ef626 49#include "log.h"
50#include "misc.h"
51#include "channels.h"
52#include "compat.h"
53#include "canohost.h"
54#include "key.h"
55#include "authfd.h"
e9a17296 56#include "pathnames.h"
0fff78ff 57#include "bufaux.h"
3c0ef626 58
59/* -- channel core */
60
dec6d9fe 61#define CHAN_RBUF 16*1024
62
3c0ef626 63/*
64 * Pointer to an array containing all allocated channels. The array is
65 * dynamically extended as needed.
66 */
67static Channel **channels = NULL;
68
69/*
70 * Size of the channel array. All slots of the array must always be
71 * initialized (at least the type field); unused slots set to NULL
72 */
c9f39d2c 73static u_int channels_alloc = 0;
3c0ef626 74
75/*
76 * Maximum file descriptor value used in any of the channels. This is
77 * updated in channel_new.
78 */
79static int channel_max_fd = 0;
80
81
82/* -- tcp forwarding */
83
84/*
85 * Data structure for storing which hosts are permitted for forward requests.
86 * The local sides of any remote forwards are stored in this array to prevent
87 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local
88 * network (which might be behind a firewall).
89 */
90typedef struct {
91 char *host_to_connect; /* Connect to 'host'. */
92 u_short port_to_connect; /* Connect to 'port'. */
93 u_short listen_port; /* Remote side should listen port number. */
94} ForwardPermission;
95
96/* List of all permitted host/port pairs to connect. */
97static ForwardPermission permitted_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
98
99/* Number of permitted host/port pairs in the array. */
100static int num_permitted_opens = 0;
101/*
102 * If this is true, all opens are permitted. This is the case on the server
103 * on which we have to trust the client anyway, and the user could do
104 * anything after logging in anyway.
105 */
106static int all_opens_permitted = 0;
107
108
109/* -- X11 forwarding */
110
111/* Maximum number of fake X11 displays to try. */
112#define MAX_DISPLAYS 1000
113
114/* Saved X11 authentication protocol name. */
115static char *x11_saved_proto = NULL;
116
117/* Saved X11 authentication data. This is the real data. */
118static char *x11_saved_data = NULL;
119static u_int x11_saved_data_len = 0;
120
121/*
122 * Fake X11 authentication data. This is what the server will be sending us;
123 * we should replace any occurrences of this by the real data.
124 */
125static char *x11_fake_data = NULL;
126static u_int x11_fake_data_len;
127
128
129/* -- agent forwarding */
130
131#define NUM_SOCKS 10
132
3c0ef626 133/* AF_UNSPEC or AF_INET or AF_INET6 */
134static int IPv4or6 = AF_UNSPEC;
135
136/* helper */
137static void port_open_helper(Channel *c, char *rtype);
138
139/* -- channel core */
140
141Channel *
142channel_lookup(int id)
143{
144 Channel *c;
145
c9f39d2c 146 if (id < 0 || (u_int)id >= channels_alloc) {
0fff78ff 147 logit("channel_lookup: %d: bad id", id);
3c0ef626 148 return NULL;
149 }
150 c = channels[id];
151 if (c == NULL) {
0fff78ff 152 logit("channel_lookup: %d: bad id: channel free", id);
3c0ef626 153 return NULL;
154 }
155 return c;
156}
157
158/*
159 * Register filedescriptors for a channel, used when allocating a channel or
160 * when the channel consumer/producer is ready, e.g. shell exec'd
161 */
162
163static void
164channel_register_fds(Channel *c, int rfd, int wfd, int efd,
165 int extusage, int nonblock)
166{
167 /* Update the maximum file descriptor value. */
168 channel_max_fd = MAX(channel_max_fd, rfd);
169 channel_max_fd = MAX(channel_max_fd, wfd);
170 channel_max_fd = MAX(channel_max_fd, efd);
171
172 /* XXX set close-on-exec -markus */
173
174 c->rfd = rfd;
175 c->wfd = wfd;
176 c->sock = (rfd == wfd) ? rfd : -1;
c9f39d2c 177 c->ctl_fd = -1; /* XXX: set elsewhere */
3c0ef626 178 c->efd = efd;
179 c->extended_usage = extusage;
180
181 /* XXX ugly hack: nonblock is only set by the server */
182 if (nonblock && isatty(c->rfd)) {
0fff78ff 183 debug2("channel %d: rfd %d isatty", c->self, c->rfd);
3c0ef626 184 c->isatty = 1;
185 if (!isatty(c->wfd)) {
186 error("channel %d: wfd %d is not a tty?",
187 c->self, c->wfd);
188 }
189 } else {
190 c->isatty = 0;
191 }
41b2f314 192 c->wfd_isatty = isatty(c->wfd);
3c0ef626 193
194 /* enable nonblocking mode */
195 if (nonblock) {
196 if (rfd != -1)
197 set_nonblock(rfd);
198 if (wfd != -1)
199 set_nonblock(wfd);
200 if (efd != -1)
201 set_nonblock(efd);
202 }
203}
204
205/*
206 * Allocate a new channel object and set its type and socket. This will cause
207 * remote_name to be freed.
208 */
209
210Channel *
211channel_new(char *ctype, int type, int rfd, int wfd, int efd,
680cee3b 212 u_int window, u_int maxpack, int extusage, char *remote_name, int nonblock)
3c0ef626 213{
c9f39d2c 214 int found;
215 u_int i;
3c0ef626 216 Channel *c;
217
218 /* Do initial allocation if this is the first call. */
219 if (channels_alloc == 0) {
3c0ef626 220 channels_alloc = 10;
221 channels = xmalloc(channels_alloc * sizeof(Channel *));
222 for (i = 0; i < channels_alloc; i++)
223 channels[i] = NULL;
3c0ef626 224 }
225 /* Try to find a free slot where to put the new channel. */
226 for (found = -1, i = 0; i < channels_alloc; i++)
227 if (channels[i] == NULL) {
228 /* Found a free slot. */
c9f39d2c 229 found = (int)i;
3c0ef626 230 break;
231 }
c9f39d2c 232 if (found < 0) {
3c0ef626 233 /* There are no free slots. Take last+1 slot and expand the array. */
234 found = channels_alloc;
680cee3b 235 if (channels_alloc > 10000)
236 fatal("channel_new: internal error: channels_alloc %d "
237 "too big.", channels_alloc);
b51b59a5 238 channels = xrealloc(channels,
239 (channels_alloc + 10) * sizeof(Channel *));
240 channels_alloc += 10;
3c0ef626 241 debug2("channel: expanding %d", channels_alloc);
3c0ef626 242 for (i = found; i < channels_alloc; i++)
243 channels[i] = NULL;
244 }
245 /* Initialize and return new channel. */
246 c = channels[found] = xmalloc(sizeof(Channel));
247 memset(c, 0, sizeof(Channel));
248 buffer_init(&c->input);
249 buffer_init(&c->output);
250 buffer_init(&c->extended);
e9a17296 251 c->ostate = CHAN_OUTPUT_OPEN;
252 c->istate = CHAN_INPUT_OPEN;
253 c->flags = 0;
3c0ef626 254 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
255 c->self = found;
256 c->type = type;
257 c->ctype = ctype;
258 c->local_window = window;
259 c->local_window_max = window;
260 c->local_consumed = 0;
261 c->local_maxpacket = maxpack;
262 c->remote_id = -1;
0fff78ff 263 c->remote_name = xstrdup(remote_name);
3c0ef626 264 c->remote_window = 0;
265 c->remote_maxpacket = 0;
3c0ef626 266 c->force_drain = 0;
e9a17296 267 c->single_connection = 0;
3c0ef626 268 c->detach_user = NULL;
e9a17296 269 c->confirm = NULL;
c9f39d2c 270 c->confirm_ctx = NULL;
3c0ef626 271 c->input_filter = NULL;
272 debug("channel %d: new [%s]", found, remote_name);
273 return c;
274}
275
276static int
277channel_find_maxfd(void)
278{
c9f39d2c 279 u_int i;
280 int max = 0;
3c0ef626 281 Channel *c;
282
283 for (i = 0; i < channels_alloc; i++) {
284 c = channels[i];
285 if (c != NULL) {
286 max = MAX(max, c->rfd);
287 max = MAX(max, c->wfd);
288 max = MAX(max, c->efd);
289 }
290 }
291 return max;
292}
293
294int
295channel_close_fd(int *fdp)
296{
297 int ret = 0, fd = *fdp;
298
299 if (fd != -1) {
300 ret = close(fd);
301 *fdp = -1;
302 if (fd == channel_max_fd)
303 channel_max_fd = channel_find_maxfd();
304 }
305 return ret;
306}
307
308/* Close all channel fd/socket. */
309
310static void
311channel_close_fds(Channel *c)
312{
c9f39d2c 313 debug3("channel %d: close_fds r %d w %d e %d c %d",
314 c->self, c->rfd, c->wfd, c->efd, c->ctl_fd);
3c0ef626 315
316 channel_close_fd(&c->sock);
c9f39d2c 317 channel_close_fd(&c->ctl_fd);
3c0ef626 318 channel_close_fd(&c->rfd);
319 channel_close_fd(&c->wfd);
320 channel_close_fd(&c->efd);
321}
322
323/* Free the channel and close its fd/socket. */
324
325void
326channel_free(Channel *c)
327{
328 char *s;
c9f39d2c 329 u_int i, n;
3c0ef626 330
331 for (n = 0, i = 0; i < channels_alloc; i++)
332 if (channels[i])
333 n++;
c9f39d2c 334 debug("channel %d: free: %s, nchannels %u", c->self,
3c0ef626 335 c->remote_name ? c->remote_name : "???", n);
336
337 s = channel_open_message();
0fff78ff 338 debug3("channel %d: status: %s", c->self, s);
3c0ef626 339 xfree(s);
340
341 if (c->sock != -1)
342 shutdown(c->sock, SHUT_RDWR);
c9f39d2c 343 if (c->ctl_fd != -1)
344 shutdown(c->ctl_fd, SHUT_RDWR);
3c0ef626 345 channel_close_fds(c);
346 buffer_free(&c->input);
347 buffer_free(&c->output);
348 buffer_free(&c->extended);
349 if (c->remote_name) {
350 xfree(c->remote_name);
351 c->remote_name = NULL;
352 }
353 channels[c->self] = NULL;
354 xfree(c);
355}
356
357void
358channel_free_all(void)
359{
c9f39d2c 360 u_int i;
3c0ef626 361
362 for (i = 0; i < channels_alloc; i++)
363 if (channels[i] != NULL)
364 channel_free(channels[i]);
365}
366
367/*
368 * Closes the sockets/fds of all channels. This is used to close extra file
369 * descriptors after a fork.
370 */
371
372void
e9a17296 373channel_close_all(void)
3c0ef626 374{
c9f39d2c 375 u_int i;
3c0ef626 376
377 for (i = 0; i < channels_alloc; i++)
378 if (channels[i] != NULL)
379 channel_close_fds(channels[i]);
380}
381
382/*
383 * Stop listening to channels.
384 */
385
386void
387channel_stop_listening(void)
388{
c9f39d2c 389 u_int i;
3c0ef626 390 Channel *c;
391
392 for (i = 0; i < channels_alloc; i++) {
393 c = channels[i];
394 if (c != NULL) {
395 switch (c->type) {
396 case SSH_CHANNEL_AUTH_SOCKET:
397 case SSH_CHANNEL_PORT_LISTENER:
398 case SSH_CHANNEL_RPORT_LISTENER:
399 case SSH_CHANNEL_X11_LISTENER:
400 channel_close_fd(&c->sock);
401 channel_free(c);
402 break;
403 }
404 }
405 }
406}
407
408/*
409 * Returns true if no channel has too much buffered data, and false if one or
410 * more channel is overfull.
411 */
412
413int
e9a17296 414channel_not_very_much_buffered_data(void)
3c0ef626 415{
416 u_int i;
417 Channel *c;
418
419 for (i = 0; i < channels_alloc; i++) {
420 c = channels[i];
421 if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
422#if 0
423 if (!compat20 &&
424 buffer_len(&c->input) > packet_get_maxsize()) {
6a9b3198 425 debug2("channel %d: big input buffer %d",
3c0ef626 426 c->self, buffer_len(&c->input));
427 return 0;
428 }
429#endif
430 if (buffer_len(&c->output) > packet_get_maxsize()) {
0fff78ff 431 debug2("channel %d: big output buffer %u > %u",
3c0ef626 432 c->self, buffer_len(&c->output),
433 packet_get_maxsize());
434 return 0;
435 }
436 }
437 }
438 return 1;
439}
440
441/* Returns true if any channel is still open. */
442
443int
e9a17296 444channel_still_open(void)
3c0ef626 445{
c9f39d2c 446 u_int i;
3c0ef626 447 Channel *c;
448
449 for (i = 0; i < channels_alloc; i++) {
450 c = channels[i];
451 if (c == NULL)
452 continue;
453 switch (c->type) {
454 case SSH_CHANNEL_X11_LISTENER:
455 case SSH_CHANNEL_PORT_LISTENER:
456 case SSH_CHANNEL_RPORT_LISTENER:
457 case SSH_CHANNEL_CLOSED:
458 case SSH_CHANNEL_AUTH_SOCKET:
459 case SSH_CHANNEL_DYNAMIC:
460 case SSH_CHANNEL_CONNECTING:
461 case SSH_CHANNEL_ZOMBIE:
462 continue;
463 case SSH_CHANNEL_LARVAL:
464 if (!compat20)
465 fatal("cannot happen: SSH_CHANNEL_LARVAL");
466 continue;
467 case SSH_CHANNEL_OPENING:
468 case SSH_CHANNEL_OPEN:
469 case SSH_CHANNEL_X11_OPEN:
470 return 1;
471 case SSH_CHANNEL_INPUT_DRAINING:
472 case SSH_CHANNEL_OUTPUT_DRAINING:
473 if (!compat13)
474 fatal("cannot happen: OUT_DRAIN");
475 return 1;
476 default:
477 fatal("channel_still_open: bad channel type %d", c->type);
478 /* NOTREACHED */
479 }
480 }
481 return 0;
482}
483
484/* Returns the id of an open channel suitable for keepaliving */
485
486int
e9a17296 487channel_find_open(void)
3c0ef626 488{
c9f39d2c 489 u_int i;
3c0ef626 490 Channel *c;
491
492 for (i = 0; i < channels_alloc; i++) {
493 c = channels[i];
c9f39d2c 494 if (c == NULL || c->remote_id < 0)
3c0ef626 495 continue;
496 switch (c->type) {
497 case SSH_CHANNEL_CLOSED:
498 case SSH_CHANNEL_DYNAMIC:
499 case SSH_CHANNEL_X11_LISTENER:
500 case SSH_CHANNEL_PORT_LISTENER:
501 case SSH_CHANNEL_RPORT_LISTENER:
502 case SSH_CHANNEL_OPENING:
503 case SSH_CHANNEL_CONNECTING:
504 case SSH_CHANNEL_ZOMBIE:
505 continue;
506 case SSH_CHANNEL_LARVAL:
507 case SSH_CHANNEL_AUTH_SOCKET:
508 case SSH_CHANNEL_OPEN:
509 case SSH_CHANNEL_X11_OPEN:
510 return i;
511 case SSH_CHANNEL_INPUT_DRAINING:
512 case SSH_CHANNEL_OUTPUT_DRAINING:
513 if (!compat13)
514 fatal("cannot happen: OUT_DRAIN");
515 return i;
516 default:
517 fatal("channel_find_open: bad channel type %d", c->type);
518 /* NOTREACHED */
519 }
520 }
521 return -1;
522}
523
524
525/*
526 * Returns a message describing the currently open forwarded connections,
527 * suitable for sending to the client. The message contains crlf pairs for
528 * newlines.
529 */
530
531char *
e9a17296 532channel_open_message(void)
3c0ef626 533{
534 Buffer buffer;
535 Channel *c;
536 char buf[1024], *cp;
c9f39d2c 537 u_int i;
3c0ef626 538
539 buffer_init(&buffer);
540 snprintf(buf, sizeof buf, "The following connections are open:\r\n");
541 buffer_append(&buffer, buf, strlen(buf));
542 for (i = 0; i < channels_alloc; i++) {
543 c = channels[i];
544 if (c == NULL)
545 continue;
546 switch (c->type) {
547 case SSH_CHANNEL_X11_LISTENER:
548 case SSH_CHANNEL_PORT_LISTENER:
549 case SSH_CHANNEL_RPORT_LISTENER:
550 case SSH_CHANNEL_CLOSED:
551 case SSH_CHANNEL_AUTH_SOCKET:
552 case SSH_CHANNEL_ZOMBIE:
553 continue;
554 case SSH_CHANNEL_LARVAL:
555 case SSH_CHANNEL_OPENING:
556 case SSH_CHANNEL_CONNECTING:
557 case SSH_CHANNEL_DYNAMIC:
558 case SSH_CHANNEL_OPEN:
559 case SSH_CHANNEL_X11_OPEN:
560 case SSH_CHANNEL_INPUT_DRAINING:
561 case SSH_CHANNEL_OUTPUT_DRAINING:
c9f39d2c 562 snprintf(buf, sizeof buf,
563 " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d cfd %d)\r\n",
3c0ef626 564 c->self, c->remote_name,
565 c->type, c->remote_id,
566 c->istate, buffer_len(&c->input),
567 c->ostate, buffer_len(&c->output),
c9f39d2c 568 c->rfd, c->wfd, c->ctl_fd);
3c0ef626 569 buffer_append(&buffer, buf, strlen(buf));
570 continue;
571 default:
572 fatal("channel_open_message: bad channel type %d", c->type);
573 /* NOTREACHED */
574 }
575 }
576 buffer_append(&buffer, "\0", 1);
577 cp = xstrdup(buffer_ptr(&buffer));
578 buffer_free(&buffer);
579 return cp;
580}
581
582void
583channel_send_open(int id)
584{
585 Channel *c = channel_lookup(id);
41b2f314 586
3c0ef626 587 if (c == NULL) {
0fff78ff 588 logit("channel_send_open: %d: bad id", id);
3c0ef626 589 return;
590 }
6a9b3198 591 debug2("channel %d: send open", id);
3c0ef626 592 packet_start(SSH2_MSG_CHANNEL_OPEN);
593 packet_put_cstring(c->ctype);
594 packet_put_int(c->self);
595 packet_put_int(c->local_window);
596 packet_put_int(c->local_maxpacket);
597 packet_send();
598}
599
600void
6a9b3198 601channel_request_start(int id, char *service, int wantconfirm)
3c0ef626 602{
6a9b3198 603 Channel *c = channel_lookup(id);
41b2f314 604
3c0ef626 605 if (c == NULL) {
0fff78ff 606 logit("channel_request_start: %d: unknown channel id", id);
3c0ef626 607 return;
608 }
c9f39d2c 609 debug2("channel %d: request %s confirm %d", id, service, wantconfirm);
3c0ef626 610 packet_start(SSH2_MSG_CHANNEL_REQUEST);
611 packet_put_int(c->remote_id);
612 packet_put_cstring(service);
613 packet_put_char(wantconfirm);
614}
615void
c9f39d2c 616channel_register_confirm(int id, channel_callback_fn *fn, void *ctx)
3c0ef626 617{
618 Channel *c = channel_lookup(id);
41b2f314 619
3c0ef626 620 if (c == NULL) {
0fff78ff 621 logit("channel_register_comfirm: %d: bad id", id);
3c0ef626 622 return;
623 }
e9a17296 624 c->confirm = fn;
c9f39d2c 625 c->confirm_ctx = ctx;
3c0ef626 626}
627void
628channel_register_cleanup(int id, channel_callback_fn *fn)
629{
630 Channel *c = channel_lookup(id);
41b2f314 631
3c0ef626 632 if (c == NULL) {
0fff78ff 633 logit("channel_register_cleanup: %d: bad id", id);
3c0ef626 634 return;
635 }
636 c->detach_user = fn;
637}
638void
639channel_cancel_cleanup(int id)
640{
641 Channel *c = channel_lookup(id);
41b2f314 642
3c0ef626 643 if (c == NULL) {
0fff78ff 644 logit("channel_cancel_cleanup: %d: bad id", id);
3c0ef626 645 return;
646 }
647 c->detach_user = NULL;
648}
649void
650channel_register_filter(int id, channel_filter_fn *fn)
651{
652 Channel *c = channel_lookup(id);
41b2f314 653
3c0ef626 654 if (c == NULL) {
0fff78ff 655 logit("channel_register_filter: %d: bad id", id);
3c0ef626 656 return;
657 }
658 c->input_filter = fn;
659}
660
661void
662channel_set_fds(int id, int rfd, int wfd, int efd,
e9a17296 663 int extusage, int nonblock, u_int window_max)
3c0ef626 664{
665 Channel *c = channel_lookup(id);
41b2f314 666
3c0ef626 667 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
668 fatal("channel_activate for non-larval channel %d.", id);
669 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
670 c->type = SSH_CHANNEL_OPEN;
e9a17296 671 c->local_window = c->local_window_max = window_max;
3c0ef626 672 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
673 packet_put_int(c->remote_id);
674 packet_put_int(c->local_window);
675 packet_send();
676}
677
678/*
679 * 'channel_pre*' are called just before select() to add any bits relevant to
680 * channels in the select bitmasks.
681 */
682/*
683 * 'channel_post*': perform any appropriate operations for channels which
684 * have events pending.
685 */
686typedef void chan_fn(Channel *c, fd_set * readset, fd_set * writeset);
687chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
688chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
689
690static void
691channel_pre_listener(Channel *c, fd_set * readset, fd_set * writeset)
692{
693 FD_SET(c->sock, readset);
694}
695
696static void
697channel_pre_connecting(Channel *c, fd_set * readset, fd_set * writeset)
698{
699 debug3("channel %d: waiting for connection", c->self);
700 FD_SET(c->sock, writeset);
701}
702
703static void
704channel_pre_open_13(Channel *c, fd_set * readset, fd_set * writeset)
705{
706 if (buffer_len(&c->input) < packet_get_maxsize())
707 FD_SET(c->sock, readset);
708 if (buffer_len(&c->output) > 0)
709 FD_SET(c->sock, writeset);
710}
711
712static void
e9a17296 713channel_pre_open(Channel *c, fd_set * readset, fd_set * writeset)
3c0ef626 714{
e9a17296 715 u_int limit = compat20 ? c->remote_window : packet_get_maxsize();
3c0ef626 716
dec6d9fe 717 /* check buffer limits */
718 limit = MIN(limit, (BUFFER_MAX_LEN - BUFFER_MAX_CHUNK - CHAN_RBUF));
719
3c0ef626 720 if (c->istate == CHAN_INPUT_OPEN &&
e9a17296 721 limit > 0 &&
722 buffer_len(&c->input) < limit)
3c0ef626 723 FD_SET(c->rfd, readset);
724 if (c->ostate == CHAN_OUTPUT_OPEN ||
725 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
726 if (buffer_len(&c->output) > 0) {
727 FD_SET(c->wfd, writeset);
728 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
700318f3 729 if (CHANNEL_EFD_OUTPUT_ACTIVE(c))
f5799ae1 730 debug2("channel %d: obuf_empty delayed efd %d/(%d)",
731 c->self, c->efd, buffer_len(&c->extended));
700318f3 732 else
733 chan_obuf_empty(c);
3c0ef626 734 }
735 }
736 /** XXX check close conditions, too */
e9a17296 737 if (compat20 && c->efd != -1) {
3c0ef626 738 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
739 buffer_len(&c->extended) > 0)
740 FD_SET(c->efd, writeset);
700318f3 741 else if (!(c->flags & CHAN_EOF_SENT) &&
742 c->extended_usage == CHAN_EXTENDED_READ &&
3c0ef626 743 buffer_len(&c->extended) < c->remote_window)
744 FD_SET(c->efd, readset);
745 }
c9f39d2c 746 /* XXX: What about efd? races? */
747 if (compat20 && c->ctl_fd != -1 &&
748 c->istate == CHAN_INPUT_OPEN && c->ostate == CHAN_OUTPUT_OPEN)
749 FD_SET(c->ctl_fd, readset);
3c0ef626 750}
751
752static void
753channel_pre_input_draining(Channel *c, fd_set * readset, fd_set * writeset)
754{
755 if (buffer_len(&c->input) == 0) {
756 packet_start(SSH_MSG_CHANNEL_CLOSE);
757 packet_put_int(c->remote_id);
758 packet_send();
759 c->type = SSH_CHANNEL_CLOSED;
0fff78ff 760 debug2("channel %d: closing after input drain.", c->self);
3c0ef626 761 }
762}
763
764static void
765channel_pre_output_draining(Channel *c, fd_set * readset, fd_set * writeset)
766{
767 if (buffer_len(&c->output) == 0)
768 chan_mark_dead(c);
769 else
770 FD_SET(c->sock, writeset);
771}
772
773/*
774 * This is a special state for X11 authentication spoofing. An opened X11
775 * connection (when authentication spoofing is being done) remains in this
776 * state until the first packet has been completely read. The authentication
777 * data in that packet is then substituted by the real data if it matches the
778 * fake data, and the channel is put into normal mode.
779 * XXX All this happens at the client side.
780 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
781 */
782static int
783x11_open_helper(Buffer *b)
784{
785 u_char *ucp;
786 u_int proto_len, data_len;
787
788 /* Check if the fixed size part of the packet is in buffer. */
789 if (buffer_len(b) < 12)
790 return 0;
791
792 /* Parse the lengths of variable-length fields. */
e9a17296 793 ucp = buffer_ptr(b);
3c0ef626 794 if (ucp[0] == 0x42) { /* Byte order MSB first. */
795 proto_len = 256 * ucp[6] + ucp[7];
796 data_len = 256 * ucp[8] + ucp[9];
797 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
798 proto_len = ucp[6] + 256 * ucp[7];
799 data_len = ucp[8] + 256 * ucp[9];
800 } else {
0fff78ff 801 debug2("Initial X11 packet contains bad byte order byte: 0x%x",
e9a17296 802 ucp[0]);
3c0ef626 803 return -1;
804 }
805
806 /* Check if the whole packet is in buffer. */
807 if (buffer_len(b) <
808 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
809 return 0;
810
811 /* Check if authentication protocol matches. */
812 if (proto_len != strlen(x11_saved_proto) ||
813 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
0fff78ff 814 debug2("X11 connection uses different authentication protocol.");
3c0ef626 815 return -1;
816 }
817 /* Check if authentication data matches our fake data. */
818 if (data_len != x11_fake_data_len ||
819 memcmp(ucp + 12 + ((proto_len + 3) & ~3),
820 x11_fake_data, x11_fake_data_len) != 0) {
0fff78ff 821 debug2("X11 auth data does not match fake data.");
3c0ef626 822 return -1;
823 }
824 /* Check fake data length */
825 if (x11_fake_data_len != x11_saved_data_len) {
826 error("X11 fake_data_len %d != saved_data_len %d",
827 x11_fake_data_len, x11_saved_data_len);
828 return -1;
829 }
830 /*
831 * Received authentication protocol and data match
832 * our fake data. Substitute the fake data with real
833 * data.
834 */
835 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
836 x11_saved_data, x11_saved_data_len);
837 return 1;
838}
839
840static void
841channel_pre_x11_open_13(Channel *c, fd_set * readset, fd_set * writeset)
842{
843 int ret = x11_open_helper(&c->output);
41b2f314 844
3c0ef626 845 if (ret == 1) {
846 /* Start normal processing for the channel. */
847 c->type = SSH_CHANNEL_OPEN;
848 channel_pre_open_13(c, readset, writeset);
849 } else if (ret == -1) {
850 /*
851 * We have received an X11 connection that has bad
852 * authentication information.
853 */
0fff78ff 854 logit("X11 connection rejected because of wrong authentication.");
3c0ef626 855 buffer_clear(&c->input);
856 buffer_clear(&c->output);
857 channel_close_fd(&c->sock);
858 c->sock = -1;
859 c->type = SSH_CHANNEL_CLOSED;
860 packet_start(SSH_MSG_CHANNEL_CLOSE);
861 packet_put_int(c->remote_id);
862 packet_send();
863 }
864}
865
866static void
867channel_pre_x11_open(Channel *c, fd_set * readset, fd_set * writeset)
868{
869 int ret = x11_open_helper(&c->output);
870
871 /* c->force_drain = 1; */
872
873 if (ret == 1) {
874 c->type = SSH_CHANNEL_OPEN;
e9a17296 875 channel_pre_open(c, readset, writeset);
3c0ef626 876 } else if (ret == -1) {
0fff78ff 877 logit("X11 connection rejected because of wrong authentication.");
878 debug2("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
e9a17296 879 chan_read_failed(c);
880 buffer_clear(&c->input);
881 chan_ibuf_empty(c);
882 buffer_clear(&c->output);
883 /* for proto v1, the peer will send an IEOF */
884 if (compat20)
885 chan_write_failed(c);
886 else
887 c->type = SSH_CHANNEL_OPEN;
0fff78ff 888 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
3c0ef626 889 }
890}
891
892/* try to decode a socks4 header */
893static int
894channel_decode_socks4(Channel *c, fd_set * readset, fd_set * writeset)
895{
41b2f314 896 char *p, *host;
3c0ef626 897 int len, have, i, found;
e9a17296 898 char username[256];
3c0ef626 899 struct {
900 u_int8_t version;
901 u_int8_t command;
902 u_int16_t dest_port;
903 struct in_addr dest_addr;
904 } s4_req, s4_rsp;
905
906 debug2("channel %d: decode socks4", c->self);
907
908 have = buffer_len(&c->input);
909 len = sizeof(s4_req);
910 if (have < len)
911 return 0;
912 p = buffer_ptr(&c->input);
913 for (found = 0, i = len; i < have; i++) {
914 if (p[i] == '\0') {
915 found = 1;
916 break;
917 }
918 if (i > 1024) {
919 /* the peer is probably sending garbage */
920 debug("channel %d: decode socks4: too long",
921 c->self);
922 return -1;
923 }
924 }
925 if (!found)
926 return 0;
927 buffer_get(&c->input, (char *)&s4_req.version, 1);
928 buffer_get(&c->input, (char *)&s4_req.command, 1);
929 buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
930 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
931 have = buffer_len(&c->input);
932 p = buffer_ptr(&c->input);
933 len = strlen(p);
934 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
935 if (len > have)
936 fatal("channel %d: decode socks4: len %d > have %d",
937 c->self, len, have);
938 strlcpy(username, p, sizeof(username));
939 buffer_consume(&c->input, len);
940 buffer_consume(&c->input, 1); /* trailing '\0' */
941
942 host = inet_ntoa(s4_req.dest_addr);
943 strlcpy(c->path, host, sizeof(c->path));
944 c->host_port = ntohs(s4_req.dest_port);
e9a17296 945
0fff78ff 946 debug2("channel %d: dynamic request: socks4 host %s port %u command %u",
3c0ef626 947 c->self, host, c->host_port, s4_req.command);
948
949 if (s4_req.command != 1) {
950 debug("channel %d: cannot handle: socks4 cn %d",
951 c->self, s4_req.command);
952 return -1;
953 }
954 s4_rsp.version = 0; /* vn: 0 for reply */
955 s4_rsp.command = 90; /* cd: req granted */
956 s4_rsp.dest_port = 0; /* ignored */
957 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
958 buffer_append(&c->output, (char *)&s4_rsp, sizeof(s4_rsp));
959 return 1;
960}
961
0fff78ff 962/* try to decode a socks5 header */
963#define SSH_SOCKS5_AUTHDONE 0x1000
964#define SSH_SOCKS5_NOAUTH 0x00
965#define SSH_SOCKS5_IPV4 0x01
966#define SSH_SOCKS5_DOMAIN 0x03
967#define SSH_SOCKS5_IPV6 0x04
968#define SSH_SOCKS5_CONNECT 0x01
969#define SSH_SOCKS5_SUCCESS 0x00
970
971static int
972channel_decode_socks5(Channel *c, fd_set * readset, fd_set * writeset)
973{
974 struct {
975 u_int8_t version;
976 u_int8_t command;
977 u_int8_t reserved;
978 u_int8_t atyp;
979 } s5_req, s5_rsp;
980 u_int16_t dest_port;
981 u_char *p, dest_addr[255+1];
982 int i, have, found, nmethods, addrlen, af;
983
984 debug2("channel %d: decode socks5", c->self);
985 p = buffer_ptr(&c->input);
986 if (p[0] != 0x05)
987 return -1;
988 have = buffer_len(&c->input);
989 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) {
990 /* format: ver | nmethods | methods */
cdd66111 991 if (have < 2)
0fff78ff 992 return 0;
993 nmethods = p[1];
994 if (have < nmethods + 2)
995 return 0;
996 /* look for method: "NO AUTHENTICATION REQUIRED" */
997 for (found = 0, i = 2 ; i < nmethods + 2; i++) {
998 if (p[i] == SSH_SOCKS5_NOAUTH ) {
999 found = 1;
1000 break;
1001 }
1002 }
1003 if (!found) {
1004 debug("channel %d: method SSH_SOCKS5_NOAUTH not found",
1005 c->self);
1006 return -1;
1007 }
1008 buffer_consume(&c->input, nmethods + 2);
1009 buffer_put_char(&c->output, 0x05); /* version */
1010 buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH); /* method */
1011 FD_SET(c->sock, writeset);
1012 c->flags |= SSH_SOCKS5_AUTHDONE;
1013 debug2("channel %d: socks5 auth done", c->self);
1014 return 0; /* need more */
1015 }
1016 debug2("channel %d: socks5 post auth", c->self);
1017 if (have < sizeof(s5_req)+1)
1018 return 0; /* need more */
1019 memcpy((char *)&s5_req, p, sizeof(s5_req));
1020 if (s5_req.version != 0x05 ||
1021 s5_req.command != SSH_SOCKS5_CONNECT ||
1022 s5_req.reserved != 0x00) {
1023 debug2("channel %d: only socks5 connect supported", c->self);
1024 return -1;
1025 }
dec6d9fe 1026 switch (s5_req.atyp){
0fff78ff 1027 case SSH_SOCKS5_IPV4:
1028 addrlen = 4;
1029 af = AF_INET;
1030 break;
1031 case SSH_SOCKS5_DOMAIN:
1032 addrlen = p[sizeof(s5_req)];
1033 af = -1;
1034 break;
1035 case SSH_SOCKS5_IPV6:
1036 addrlen = 16;
1037 af = AF_INET6;
1038 break;
1039 default:
1040 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp);
1041 return -1;
1042 }
1043 if (have < 4 + addrlen + 2)
1044 return 0;
1045 buffer_consume(&c->input, sizeof(s5_req));
1046 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1047 buffer_consume(&c->input, 1); /* host string length */
1048 buffer_get(&c->input, (char *)&dest_addr, addrlen);
1049 buffer_get(&c->input, (char *)&dest_port, 2);
1050 dest_addr[addrlen] = '\0';
1051 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
c9f39d2c 1052 strlcpy(c->path, (char *)dest_addr, sizeof(c->path));
0fff78ff 1053 else if (inet_ntop(af, dest_addr, c->path, sizeof(c->path)) == NULL)
1054 return -1;
1055 c->host_port = ntohs(dest_port);
cdd66111 1056
0fff78ff 1057 debug2("channel %d: dynamic request: socks5 host %s port %u command %u",
1058 c->self, c->path, c->host_port, s5_req.command);
1059
1060 s5_rsp.version = 0x05;
1061 s5_rsp.command = SSH_SOCKS5_SUCCESS;
1062 s5_rsp.reserved = 0; /* ignored */
1063 s5_rsp.atyp = SSH_SOCKS5_IPV4;
1064 ((struct in_addr *)&dest_addr)->s_addr = INADDR_ANY;
1065 dest_port = 0; /* ignored */
1066
1067 buffer_append(&c->output, (char *)&s5_rsp, sizeof(s5_rsp));
1068 buffer_append(&c->output, (char *)&dest_addr, sizeof(struct in_addr));
1069 buffer_append(&c->output, (char *)&dest_port, sizeof(dest_port));
1070 return 1;
1071}
1072
3c0ef626 1073/* dynamic port forwarding */
1074static void
1075channel_pre_dynamic(Channel *c, fd_set * readset, fd_set * writeset)
1076{
1077 u_char *p;
1078 int have, ret;
1079
1080 have = buffer_len(&c->input);
1081 c->delayed = 0;
1082 debug2("channel %d: pre_dynamic: have %d", c->self, have);
1083 /* buffer_dump(&c->input); */
1084 /* check if the fixed size part of the packet is in buffer. */
0fff78ff 1085 if (have < 3) {
3c0ef626 1086 /* need more */
1087 FD_SET(c->sock, readset);
1088 return;
1089 }
1090 /* try to guess the protocol */
1091 p = buffer_ptr(&c->input);
1092 switch (p[0]) {
1093 case 0x04:
1094 ret = channel_decode_socks4(c, readset, writeset);
1095 break;
0fff78ff 1096 case 0x05:
1097 ret = channel_decode_socks5(c, readset, writeset);
1098 break;
3c0ef626 1099 default:
1100 ret = -1;
1101 break;
1102 }
1103 if (ret < 0) {
1104 chan_mark_dead(c);
1105 } else if (ret == 0) {
1106 debug2("channel %d: pre_dynamic: need more", c->self);
1107 /* need more */
1108 FD_SET(c->sock, readset);
1109 } else {
1110 /* switch to the next state */
1111 c->type = SSH_CHANNEL_OPENING;
1112 port_open_helper(c, "direct-tcpip");
1113 }
1114}
1115
1116/* This is our fake X11 server socket. */
1117static void
1118channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset)
1119{
1120 Channel *nc;
1121 struct sockaddr addr;
1122 int newsock;
1123 socklen_t addrlen;
1124 char buf[16384], *remote_ipaddr;
1125 int remote_port;
1126
1127 if (FD_ISSET(c->sock, readset)) {
1128 debug("X11 connection requested.");
1129 addrlen = sizeof(addr);
1130 newsock = accept(c->sock, &addr, &addrlen);
e9a17296 1131 if (c->single_connection) {
0fff78ff 1132 debug2("single_connection: closing X11 listener.");
e9a17296 1133 channel_close_fd(&c->sock);
1134 chan_mark_dead(c);
1135 }
3c0ef626 1136 if (newsock < 0) {
1137 error("accept: %.100s", strerror(errno));
1138 return;
1139 }
e9a17296 1140 set_nodelay(newsock);
3c0ef626 1141 remote_ipaddr = get_peer_ipaddr(newsock);
1142 remote_port = get_peer_port(newsock);
1143 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1144 remote_ipaddr, remote_port);
1145
1146 nc = channel_new("accepted x11 socket",
1147 SSH_CHANNEL_OPENING, newsock, newsock, -1,
0fff78ff 1148 c->local_window_max, c->local_maxpacket, 0, buf, 1);
3c0ef626 1149 if (compat20) {
1150 packet_start(SSH2_MSG_CHANNEL_OPEN);
1151 packet_put_cstring("x11");
1152 packet_put_int(nc->self);
e9a17296 1153 packet_put_int(nc->local_window_max);
1154 packet_put_int(nc->local_maxpacket);
3c0ef626 1155 /* originator ipaddr and port */
1156 packet_put_cstring(remote_ipaddr);
1157 if (datafellows & SSH_BUG_X11FWD) {
0fff78ff 1158 debug2("ssh2 x11 bug compat mode");
3c0ef626 1159 } else {
1160 packet_put_int(remote_port);
1161 }
1162 packet_send();
1163 } else {
1164 packet_start(SSH_SMSG_X11_OPEN);
1165 packet_put_int(nc->self);
1166 if (packet_get_protocol_flags() &
1167 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1168 packet_put_cstring(buf);
1169 packet_send();
1170 }
1171 xfree(remote_ipaddr);
1172 }
1173}
1174
1175static void
1176port_open_helper(Channel *c, char *rtype)
1177{
1178 int direct;
1179 char buf[1024];
1180 char *remote_ipaddr = get_peer_ipaddr(c->sock);
1181 u_short remote_port = get_peer_port(c->sock);
1182
1183 direct = (strcmp(rtype, "direct-tcpip") == 0);
1184
1185 snprintf(buf, sizeof buf,
1186 "%s: listening port %d for %.100s port %d, "
1187 "connect from %.200s port %d",
1188 rtype, c->listening_port, c->path, c->host_port,
1189 remote_ipaddr, remote_port);
1190
1191 xfree(c->remote_name);
1192 c->remote_name = xstrdup(buf);
1193
1194 if (compat20) {
1195 packet_start(SSH2_MSG_CHANNEL_OPEN);
1196 packet_put_cstring(rtype);
1197 packet_put_int(c->self);
1198 packet_put_int(c->local_window_max);
1199 packet_put_int(c->local_maxpacket);
1200 if (direct) {
1201 /* target host, port */
1202 packet_put_cstring(c->path);
1203 packet_put_int(c->host_port);
1204 } else {
1205 /* listen address, port */
1206 packet_put_cstring(c->path);
1207 packet_put_int(c->listening_port);
1208 }
1209 /* originator host and port */
1210 packet_put_cstring(remote_ipaddr);
1211 packet_put_int(remote_port);
1212 packet_send();
1213 } else {
1214 packet_start(SSH_MSG_PORT_OPEN);
1215 packet_put_int(c->self);
1216 packet_put_cstring(c->path);
1217 packet_put_int(c->host_port);
1218 if (packet_get_protocol_flags() &
1219 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1220 packet_put_cstring(c->remote_name);
1221 packet_send();
1222 }
1223 xfree(remote_ipaddr);
1224}
1225
1226/*
1227 * This socket is listening for connections to a forwarded TCP/IP port.
1228 */
1229static void
1230channel_post_port_listener(Channel *c, fd_set * readset, fd_set * writeset)
1231{
1232 Channel *nc;
1233 struct sockaddr addr;
1234 int newsock, nextstate;
1235 socklen_t addrlen;
1236 char *rtype;
1237
1238 if (FD_ISSET(c->sock, readset)) {
1239 debug("Connection to port %d forwarding "
1240 "to %.100s port %d requested.",
1241 c->listening_port, c->path, c->host_port);
1242
1243 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1244 nextstate = SSH_CHANNEL_OPENING;
1245 rtype = "forwarded-tcpip";
1246 } else {
1247 if (c->host_port == 0) {
1248 nextstate = SSH_CHANNEL_DYNAMIC;
1249 rtype = "dynamic-tcpip";
1250 } else {
1251 nextstate = SSH_CHANNEL_OPENING;
1252 rtype = "direct-tcpip";
1253 }
1254 }
1255
1256 addrlen = sizeof(addr);
1257 newsock = accept(c->sock, &addr, &addrlen);
1258 if (newsock < 0) {
1259 error("accept: %.100s", strerror(errno));
1260 return;
1261 }
e9a17296 1262 set_nodelay(newsock);
0fff78ff 1263 nc = channel_new(rtype, nextstate, newsock, newsock, -1,
1264 c->local_window_max, c->local_maxpacket, 0, rtype, 1);
3c0ef626 1265 nc->listening_port = c->listening_port;
1266 nc->host_port = c->host_port;
1267 strlcpy(nc->path, c->path, sizeof(nc->path));
1268
1269 if (nextstate == SSH_CHANNEL_DYNAMIC) {
1270 /*
1271 * do not call the channel_post handler until
1272 * this flag has been reset by a pre-handler.
1273 * otherwise the FD_ISSET calls might overflow
1274 */
1275 nc->delayed = 1;
1276 } else {
1277 port_open_helper(nc, rtype);
1278 }
1279 }
1280}
1281
1282/*
1283 * This is the authentication agent socket listening for connections from
1284 * clients.
1285 */
1286static void
1287channel_post_auth_listener(Channel *c, fd_set * readset, fd_set * writeset)
1288{
1289 Channel *nc;
3c0ef626 1290 int newsock;
1291 struct sockaddr addr;
1292 socklen_t addrlen;
1293
1294 if (FD_ISSET(c->sock, readset)) {
1295 addrlen = sizeof(addr);
1296 newsock = accept(c->sock, &addr, &addrlen);
1297 if (newsock < 0) {
1298 error("accept from auth socket: %.100s", strerror(errno));
1299 return;
1300 }
3c0ef626 1301 nc = channel_new("accepted auth socket",
1302 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1303 c->local_window_max, c->local_maxpacket,
0fff78ff 1304 0, "accepted auth socket", 1);
3c0ef626 1305 if (compat20) {
1306 packet_start(SSH2_MSG_CHANNEL_OPEN);
1307 packet_put_cstring("auth-agent@openssh.com");
1308 packet_put_int(nc->self);
1309 packet_put_int(c->local_window_max);
1310 packet_put_int(c->local_maxpacket);
1311 } else {
1312 packet_start(SSH_SMSG_AGENT_OPEN);
1313 packet_put_int(nc->self);
1314 }
1315 packet_send();
1316 }
1317}
1318
1319static void
1320channel_post_connecting(Channel *c, fd_set * readset, fd_set * writeset)
1321{
1322 int err = 0;
1323 socklen_t sz = sizeof(err);
1324
1325 if (FD_ISSET(c->sock, writeset)) {
e9a17296 1326 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) {
3c0ef626 1327 err = errno;
1328 error("getsockopt SO_ERROR failed");
1329 }
1330 if (err == 0) {
1331 debug("channel %d: connected", c->self);
1332 c->type = SSH_CHANNEL_OPEN;
1333 if (compat20) {
1334 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1335 packet_put_int(c->remote_id);
1336 packet_put_int(c->self);
1337 packet_put_int(c->local_window);
1338 packet_put_int(c->local_maxpacket);
1339 } else {
1340 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1341 packet_put_int(c->remote_id);
1342 packet_put_int(c->self);
1343 }
1344 } else {
1345 debug("channel %d: not connected: %s",
1346 c->self, strerror(err));
1347 if (compat20) {
1348 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1349 packet_put_int(c->remote_id);
1350 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1351 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1352 packet_put_cstring(strerror(err));
1353 packet_put_cstring("");
1354 }
1355 } else {
1356 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1357 packet_put_int(c->remote_id);
1358 }
1359 chan_mark_dead(c);
1360 }
1361 packet_send();
1362 }
1363}
1364
1365static int
1366channel_handle_rfd(Channel *c, fd_set * readset, fd_set * writeset)
1367{
dec6d9fe 1368 char buf[CHAN_RBUF];
3c0ef626 1369 int len;
1370
1371 if (c->rfd != -1 &&
1372 FD_ISSET(c->rfd, readset)) {
1373 len = read(c->rfd, buf, sizeof(buf));
1374 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1375 return 1;
1376 if (len <= 0) {
0fff78ff 1377 debug2("channel %d: read<=0 rfd %d len %d",
3c0ef626 1378 c->self, c->rfd, len);
1379 if (c->type != SSH_CHANNEL_OPEN) {
0fff78ff 1380 debug2("channel %d: not open", c->self);
3c0ef626 1381 chan_mark_dead(c);
1382 return -1;
1383 } else if (compat13) {
e9a17296 1384 buffer_clear(&c->output);
3c0ef626 1385 c->type = SSH_CHANNEL_INPUT_DRAINING;
0fff78ff 1386 debug2("channel %d: input draining.", c->self);
3c0ef626 1387 } else {
1388 chan_read_failed(c);
1389 }
1390 return -1;
1391 }
e9a17296 1392 if (c->input_filter != NULL) {
3c0ef626 1393 if (c->input_filter(c, buf, len) == -1) {
0fff78ff 1394 debug2("channel %d: filter stops", c->self);
3c0ef626 1395 chan_read_failed(c);
1396 }
1397 } else {
1398 buffer_append(&c->input, buf, len);
1399 }
1400 }
1401 return 1;
1402}
1403static int
1404channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset)
1405{
1406 struct termios tio;
1407 u_char *data;
1408 u_int dlen;
1409 int len;
1410
1411 /* Send buffered output data to the socket. */
1412 if (c->wfd != -1 &&
1413 FD_ISSET(c->wfd, writeset) &&
1414 buffer_len(&c->output) > 0) {
1415 data = buffer_ptr(&c->output);
1416 dlen = buffer_len(&c->output);
41b2f314 1417#ifdef _AIX
cdd66111 1418 /* XXX: Later AIX versions can't push as much data to tty */
1419 if (compat20 && c->wfd_isatty)
1420 dlen = MIN(dlen, 8*1024);
41b2f314 1421#endif
3c0ef626 1422 len = write(c->wfd, data, dlen);
1423 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1424 return 1;
1425 if (len <= 0) {
1426 if (c->type != SSH_CHANNEL_OPEN) {
0fff78ff 1427 debug2("channel %d: not open", c->self);
3c0ef626 1428 chan_mark_dead(c);
1429 return -1;
1430 } else if (compat13) {
e9a17296 1431 buffer_clear(&c->output);
0fff78ff 1432 debug2("channel %d: input draining.", c->self);
3c0ef626 1433 c->type = SSH_CHANNEL_INPUT_DRAINING;
1434 } else {
1435 chan_write_failed(c);
1436 }
1437 return -1;
1438 }
1439 if (compat20 && c->isatty && dlen >= 1 && data[0] != '\r') {
1440 if (tcgetattr(c->wfd, &tio) == 0 &&
1441 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1442 /*
1443 * Simulate echo to reduce the impact of
1444 * traffic analysis. We need to match the
1445 * size of a SSH2_MSG_CHANNEL_DATA message
1446 * (4 byte channel id + data)
1447 */
1448 packet_send_ignore(4 + len);
1449 packet_send();
1450 }
1451 }
1452 buffer_consume(&c->output, len);
1453 if (compat20 && len > 0) {
1454 c->local_consumed += len;
1455 }
1456 }
1457 return 1;
1458}
1459static int
1460channel_handle_efd(Channel *c, fd_set * readset, fd_set * writeset)
1461{
dec6d9fe 1462 char buf[CHAN_RBUF];
3c0ef626 1463 int len;
1464
1465/** XXX handle drain efd, too */
1466 if (c->efd != -1) {
1467 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1468 FD_ISSET(c->efd, writeset) &&
1469 buffer_len(&c->extended) > 0) {
1470 len = write(c->efd, buffer_ptr(&c->extended),
1471 buffer_len(&c->extended));
1472 debug2("channel %d: written %d to efd %d",
1473 c->self, len, c->efd);
1474 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1475 return 1;
1476 if (len <= 0) {
1477 debug2("channel %d: closing write-efd %d",
1478 c->self, c->efd);
1479 channel_close_fd(&c->efd);
1480 } else {
1481 buffer_consume(&c->extended, len);
1482 c->local_consumed += len;
1483 }
1484 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
1485 FD_ISSET(c->efd, readset)) {
1486 len = read(c->efd, buf, sizeof(buf));
1487 debug2("channel %d: read %d from efd %d",
e9a17296 1488 c->self, len, c->efd);
3c0ef626 1489 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1490 return 1;
1491 if (len <= 0) {
1492 debug2("channel %d: closing read-efd %d",
1493 c->self, c->efd);
1494 channel_close_fd(&c->efd);
1495 } else {
1496 buffer_append(&c->extended, buf, len);
1497 }
1498 }
1499 }
1500 return 1;
1501}
1502static int
c9f39d2c 1503channel_handle_ctl(Channel *c, fd_set * readset, fd_set * writeset)
1504{
1505 char buf[16];
1506 int len;
1507
1508 /* Monitor control fd to detect if the slave client exits */
1509 if (c->ctl_fd != -1 && FD_ISSET(c->ctl_fd, readset)) {
1510 len = read(c->ctl_fd, buf, sizeof(buf));
1511 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1512 return 1;
1513 if (len <= 0) {
1514 debug2("channel %d: ctl read<=0", c->self);
1515 if (c->type != SSH_CHANNEL_OPEN) {
1516 debug2("channel %d: not open", c->self);
1517 chan_mark_dead(c);
1518 return -1;
1519 } else {
1520 chan_read_failed(c);
1521 chan_write_failed(c);
1522 }
1523 return -1;
1524 } else
1525 fatal("%s: unexpected data on ctl fd", __func__);
1526 }
1527 return 1;
1528}
1529static int
3c0ef626 1530channel_check_window(Channel *c)
1531{
1532 if (c->type == SSH_CHANNEL_OPEN &&
1533 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1534 c->local_window < c->local_window_max/2 &&
1535 c->local_consumed > 0) {
1536 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1537 packet_put_int(c->remote_id);
1538 packet_put_int(c->local_consumed);
1539 packet_send();
1540 debug2("channel %d: window %d sent adjust %d",
1541 c->self, c->local_window,
1542 c->local_consumed);
1543 c->local_window += c->local_consumed;
1544 c->local_consumed = 0;
1545 }
1546 return 1;
1547}
1548
1549static void
e9a17296 1550channel_post_open(Channel *c, fd_set * readset, fd_set * writeset)
3c0ef626 1551{
1552 if (c->delayed)
1553 return;
1554 channel_handle_rfd(c, readset, writeset);
1555 channel_handle_wfd(c, readset, writeset);
e9a17296 1556 if (!compat20)
3c0ef626 1557 return;
3c0ef626 1558 channel_handle_efd(c, readset, writeset);
c9f39d2c 1559 channel_handle_ctl(c, readset, writeset);
3c0ef626 1560 channel_check_window(c);
1561}
1562
1563static void
1564channel_post_output_drain_13(Channel *c, fd_set * readset, fd_set * writeset)
1565{
1566 int len;
41b2f314 1567
3c0ef626 1568 /* Send buffered output data to the socket. */
1569 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1570 len = write(c->sock, buffer_ptr(&c->output),
1571 buffer_len(&c->output));
1572 if (len <= 0)
e9a17296 1573 buffer_clear(&c->output);
3c0ef626 1574 else
1575 buffer_consume(&c->output, len);
1576 }
1577}
1578
1579static void
1580channel_handler_init_20(void)
1581{
e9a17296 1582 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
3c0ef626 1583 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1584 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1585 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
1586 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1587 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1588 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1589 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1590
e9a17296 1591 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
3c0ef626 1592 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1593 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
1594 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1595 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1596 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
e9a17296 1597 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
3c0ef626 1598}
1599
1600static void
1601channel_handler_init_13(void)
1602{
1603 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
1604 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
1605 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1606 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1607 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1608 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
1609 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1610 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1611 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1612
e9a17296 1613 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
3c0ef626 1614 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1615 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1616 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1617 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
1618 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
e9a17296 1619 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
3c0ef626 1620}
1621
1622static void
1623channel_handler_init_15(void)
1624{
e9a17296 1625 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
3c0ef626 1626 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1627 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1628 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1629 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1630 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1631 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1632
1633 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1634 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1635 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
e9a17296 1636 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
3c0ef626 1637 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
e9a17296 1638 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
3c0ef626 1639}
1640
1641static void
1642channel_handler_init(void)
1643{
1644 int i;
41b2f314 1645
e9a17296 1646 for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
3c0ef626 1647 channel_pre[i] = NULL;
1648 channel_post[i] = NULL;
1649 }
1650 if (compat20)
1651 channel_handler_init_20();
1652 else if (compat13)
1653 channel_handler_init_13();
1654 else
1655 channel_handler_init_15();
1656}
1657
1658/* gc dead channels */
1659static void
1660channel_garbage_collect(Channel *c)
1661{
1662 if (c == NULL)
1663 return;
1664 if (c->detach_user != NULL) {
1665 if (!chan_is_dead(c, 0))
1666 return;
0fff78ff 1667 debug2("channel %d: gc: notify user", c->self);
3c0ef626 1668 c->detach_user(c->self, NULL);
1669 /* if we still have a callback */
1670 if (c->detach_user != NULL)
1671 return;
0fff78ff 1672 debug2("channel %d: gc: user detached", c->self);
3c0ef626 1673 }
1674 if (!chan_is_dead(c, 1))
1675 return;
0fff78ff 1676 debug2("channel %d: garbage collecting", c->self);
3c0ef626 1677 channel_free(c);
1678}
1679
1680static void
1681channel_handler(chan_fn *ftab[], fd_set * readset, fd_set * writeset)
1682{
1683 static int did_init = 0;
c9f39d2c 1684 u_int i;
3c0ef626 1685 Channel *c;
1686
1687 if (!did_init) {
1688 channel_handler_init();
1689 did_init = 1;
1690 }
1691 for (i = 0; i < channels_alloc; i++) {
1692 c = channels[i];
1693 if (c == NULL)
1694 continue;
1695 if (ftab[c->type] != NULL)
1696 (*ftab[c->type])(c, readset, writeset);
1697 channel_garbage_collect(c);
1698 }
1699}
1700
1701/*
1702 * Allocate/update select bitmasks and add any bits relevant to channels in
1703 * select bitmasks.
1704 */
1705void
1706channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
c9f39d2c 1707 u_int *nallocp, int rekeying)
3c0ef626 1708{
c9f39d2c 1709 u_int n, sz;
3c0ef626 1710
1711 n = MAX(*maxfdp, channel_max_fd);
1712
1713 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask);
1714 /* perhaps check sz < nalloc/2 and shrink? */
1715 if (*readsetp == NULL || sz > *nallocp) {
1716 *readsetp = xrealloc(*readsetp, sz);
1717 *writesetp = xrealloc(*writesetp, sz);
1718 *nallocp = sz;
1719 }
1720 *maxfdp = n;
1721 memset(*readsetp, 0, sz);
1722 memset(*writesetp, 0, sz);
1723
1724 if (!rekeying)
1725 channel_handler(channel_pre, *readsetp, *writesetp);
1726}
1727
1728/*
1729 * After select, perform any appropriate operations for channels which have
1730 * events pending.
1731 */
1732void
1733channel_after_select(fd_set * readset, fd_set * writeset)
1734{
1735 channel_handler(channel_post, readset, writeset);
1736}
1737
1738
1739/* If there is data to send to the connection, enqueue some of it now. */
1740
1741void
e9a17296 1742channel_output_poll(void)
3c0ef626 1743{
3c0ef626 1744 Channel *c;
c9f39d2c 1745 u_int i, len;
3c0ef626 1746
1747 for (i = 0; i < channels_alloc; i++) {
1748 c = channels[i];
1749 if (c == NULL)
1750 continue;
1751
1752 /*
1753 * We are only interested in channels that can have buffered
1754 * incoming data.
1755 */
1756 if (compat13) {
1757 if (c->type != SSH_CHANNEL_OPEN &&
1758 c->type != SSH_CHANNEL_INPUT_DRAINING)
1759 continue;
1760 } else {
1761 if (c->type != SSH_CHANNEL_OPEN)
1762 continue;
1763 }
1764 if (compat20 &&
1765 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
1766 /* XXX is this true? */
1767 debug3("channel %d: will not send data after close", c->self);
1768 continue;
1769 }
1770
1771 /* Get the amount of buffered data for this channel. */
1772 if ((c->istate == CHAN_INPUT_OPEN ||
1773 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
1774 (len = buffer_len(&c->input)) > 0) {
1775 /*
1776 * Send some data for the other side over the secure
1777 * connection.
1778 */
1779 if (compat20) {
1780 if (len > c->remote_window)
1781 len = c->remote_window;
1782 if (len > c->remote_maxpacket)
1783 len = c->remote_maxpacket;
1784 } else {
1785 if (packet_is_interactive()) {
1786 if (len > 1024)
1787 len = 512;
1788 } else {
1789 /* Keep the packets at reasonable size. */
1790 if (len > packet_get_maxsize()/2)
1791 len = packet_get_maxsize()/2;
1792 }
1793 }
1794 if (len > 0) {
1795 packet_start(compat20 ?
1796 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
1797 packet_put_int(c->remote_id);
1798 packet_put_string(buffer_ptr(&c->input), len);
1799 packet_send();
1800 buffer_consume(&c->input, len);
1801 c->remote_window -= len;
1802 }
1803 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1804 if (compat13)
1805 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
1806 /*
1807 * input-buffer is empty and read-socket shutdown:
700318f3 1808 * tell peer, that we will not send more data: send IEOF.
1809 * hack for extended data: delay EOF if EFD still in use.
3c0ef626 1810 */
700318f3 1811 if (CHANNEL_EFD_INPUT_ACTIVE(c))
f5799ae1 1812 debug2("channel %d: ibuf_empty delayed efd %d/(%d)",
1813 c->self, c->efd, buffer_len(&c->extended));
700318f3 1814 else
1815 chan_ibuf_empty(c);
3c0ef626 1816 }
1817 /* Send extended data, i.e. stderr */
1818 if (compat20 &&
700318f3 1819 !(c->flags & CHAN_EOF_SENT) &&
3c0ef626 1820 c->remote_window > 0 &&
1821 (len = buffer_len(&c->extended)) > 0 &&
1822 c->extended_usage == CHAN_EXTENDED_READ) {
680cee3b 1823 debug2("channel %d: rwin %u elen %u euse %d",
3c0ef626 1824 c->self, c->remote_window, buffer_len(&c->extended),
1825 c->extended_usage);
1826 if (len > c->remote_window)
1827 len = c->remote_window;
1828 if (len > c->remote_maxpacket)
1829 len = c->remote_maxpacket;
1830 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
1831 packet_put_int(c->remote_id);
1832 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
1833 packet_put_string(buffer_ptr(&c->extended), len);
1834 packet_send();
1835 buffer_consume(&c->extended, len);
1836 c->remote_window -= len;
1837 debug2("channel %d: sent ext data %d", c->self, len);
1838 }
1839 }
1840}
1841
1842
1843/* -- protocol input */
1844
1845void
e9a17296 1846channel_input_data(int type, u_int32_t seq, void *ctxt)
3c0ef626 1847{
1848 int id;
1849 char *data;
1850 u_int data_len;
1851 Channel *c;
1852
1853 /* Get the channel number and verify it. */
1854 id = packet_get_int();
1855 c = channel_lookup(id);
1856 if (c == NULL)
1857 packet_disconnect("Received data for nonexistent channel %d.", id);
1858
1859 /* Ignore any data for non-open channels (might happen on close) */
1860 if (c->type != SSH_CHANNEL_OPEN &&
1861 c->type != SSH_CHANNEL_X11_OPEN)
1862 return;
1863
3c0ef626 1864 /* Get the data. */
1865 data = packet_get_string(&data_len);
3c0ef626 1866
cdd66111 1867 /*
1868 * Ignore data for protocol > 1.3 if output end is no longer open.
1869 * For protocol 2 the sending side is reducing its window as it sends
1870 * data, so we must 'fake' consumption of the data in order to ensure
1871 * that window updates are sent back. Otherwise the connection might
1872 * deadlock.
1873 */
1874 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) {
1875 if (compat20) {
1876 c->local_window -= data_len;
1877 c->local_consumed += data_len;
1878 }
1879 xfree(data);
1880 return;
1881 }
1882
e9a17296 1883 if (compat20) {
3c0ef626 1884 if (data_len > c->local_maxpacket) {
0fff78ff 1885 logit("channel %d: rcvd big packet %d, maxpack %d",
3c0ef626 1886 c->self, data_len, c->local_maxpacket);
1887 }
1888 if (data_len > c->local_window) {
0fff78ff 1889 logit("channel %d: rcvd too much data %d, win %d",
3c0ef626 1890 c->self, data_len, c->local_window);
1891 xfree(data);
1892 return;
1893 }
1894 c->local_window -= data_len;
3c0ef626 1895 }
e9a17296 1896 packet_check_eom();
3c0ef626 1897 buffer_append(&c->output, data, data_len);
1898 xfree(data);
1899}
1900
1901void
e9a17296 1902channel_input_extended_data(int type, u_int32_t seq, void *ctxt)
3c0ef626 1903{
1904 int id;
3c0ef626 1905 char *data;
680cee3b 1906 u_int data_len, tcode;
3c0ef626 1907 Channel *c;
1908
1909 /* Get the channel number and verify it. */
1910 id = packet_get_int();
1911 c = channel_lookup(id);
1912
1913 if (c == NULL)
1914 packet_disconnect("Received extended_data for bad channel %d.", id);
1915 if (c->type != SSH_CHANNEL_OPEN) {
0fff78ff 1916 logit("channel %d: ext data for non open", id);
3c0ef626 1917 return;
1918 }
700318f3 1919 if (c->flags & CHAN_EOF_RCVD) {
1920 if (datafellows & SSH_BUG_EXTEOF)
1921 debug("channel %d: accepting ext data after eof", id);
1922 else
1923 packet_disconnect("Received extended_data after EOF "
1924 "on channel %d.", id);
1925 }
3c0ef626 1926 tcode = packet_get_int();
1927 if (c->efd == -1 ||
1928 c->extended_usage != CHAN_EXTENDED_WRITE ||
1929 tcode != SSH2_EXTENDED_DATA_STDERR) {
0fff78ff 1930 logit("channel %d: bad ext data", c->self);
3c0ef626 1931 return;
1932 }
1933 data = packet_get_string(&data_len);
e9a17296 1934 packet_check_eom();
3c0ef626 1935 if (data_len > c->local_window) {
0fff78ff 1936 logit("channel %d: rcvd too much extended_data %d, win %d",
3c0ef626 1937 c->self, data_len, c->local_window);
1938 xfree(data);
1939 return;
1940 }
1941 debug2("channel %d: rcvd ext data %d", c->self, data_len);
1942 c->local_window -= data_len;
1943 buffer_append(&c->extended, data, data_len);
1944 xfree(data);
1945}
1946
1947void
e9a17296 1948channel_input_ieof(int type, u_int32_t seq, void *ctxt)
3c0ef626 1949{
1950 int id;
1951 Channel *c;
1952
3c0ef626 1953 id = packet_get_int();
e9a17296 1954 packet_check_eom();
3c0ef626 1955 c = channel_lookup(id);
1956 if (c == NULL)
1957 packet_disconnect("Received ieof for nonexistent channel %d.", id);
1958 chan_rcvd_ieof(c);
1959
1960 /* XXX force input close */
e9a17296 1961 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) {
3c0ef626 1962 debug("channel %d: FORCE input drain", c->self);
1963 c->istate = CHAN_INPUT_WAIT_DRAIN;
e9a17296 1964 if (buffer_len(&c->input) == 0)
1965 chan_ibuf_empty(c);
3c0ef626 1966 }
1967
1968}
1969
1970void
e9a17296 1971channel_input_close(int type, u_int32_t seq, void *ctxt)
3c0ef626 1972{
1973 int id;
1974 Channel *c;
1975
3c0ef626 1976 id = packet_get_int();
e9a17296 1977 packet_check_eom();
3c0ef626 1978 c = channel_lookup(id);
1979 if (c == NULL)
1980 packet_disconnect("Received close for nonexistent channel %d.", id);
1981
1982 /*
1983 * Send a confirmation that we have closed the channel and no more
1984 * data is coming for it.
1985 */
1986 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
1987 packet_put_int(c->remote_id);
1988 packet_send();
1989
1990 /*
1991 * If the channel is in closed state, we have sent a close request,
1992 * and the other side will eventually respond with a confirmation.
1993 * Thus, we cannot free the channel here, because then there would be
1994 * no-one to receive the confirmation. The channel gets freed when
1995 * the confirmation arrives.
1996 */
1997 if (c->type != SSH_CHANNEL_CLOSED) {
1998 /*
1999 * Not a closed channel - mark it as draining, which will
2000 * cause it to be freed later.
2001 */
e9a17296 2002 buffer_clear(&c->input);
3c0ef626 2003 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
2004 }
2005}
2006
2007/* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
2008void
e9a17296 2009channel_input_oclose(int type, u_int32_t seq, void *ctxt)
3c0ef626 2010{
2011 int id = packet_get_int();
2012 Channel *c = channel_lookup(id);
e9a17296 2013
2014 packet_check_eom();
3c0ef626 2015 if (c == NULL)
2016 packet_disconnect("Received oclose for nonexistent channel %d.", id);
2017 chan_rcvd_oclose(c);
2018}
2019
2020void
e9a17296 2021channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt)
3c0ef626 2022{
2023 int id = packet_get_int();
2024 Channel *c = channel_lookup(id);
2025
e9a17296 2026 packet_check_eom();
3c0ef626 2027 if (c == NULL)
2028 packet_disconnect("Received close confirmation for "
2029 "out-of-range channel %d.", id);
2030 if (c->type != SSH_CHANNEL_CLOSED)
2031 packet_disconnect("Received close confirmation for "
2032 "non-closed channel %d (type %d).", id, c->type);
2033 channel_free(c);
2034}
2035
2036void
e9a17296 2037channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt)
3c0ef626 2038{
2039 int id, remote_id;
2040 Channel *c;
2041
3c0ef626 2042 id = packet_get_int();
2043 c = channel_lookup(id);
2044
2045 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2046 packet_disconnect("Received open confirmation for "
2047 "non-opening channel %d.", id);
2048 remote_id = packet_get_int();
2049 /* Record the remote channel number and mark that the channel is now open. */
2050 c->remote_id = remote_id;
2051 c->type = SSH_CHANNEL_OPEN;
2052
2053 if (compat20) {
2054 c->remote_window = packet_get_int();
2055 c->remote_maxpacket = packet_get_int();
e9a17296 2056 if (c->confirm) {
3c0ef626 2057 debug2("callback start");
c9f39d2c 2058 c->confirm(c->self, c->confirm_ctx);
3c0ef626 2059 debug2("callback done");
2060 }
0fff78ff 2061 debug2("channel %d: open confirm rwindow %u rmax %u", c->self,
3c0ef626 2062 c->remote_window, c->remote_maxpacket);
2063 }
e9a17296 2064 packet_check_eom();
3c0ef626 2065}
2066
2067static char *
2068reason2txt(int reason)
2069{
e9a17296 2070 switch (reason) {
3c0ef626 2071 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
2072 return "administratively prohibited";
2073 case SSH2_OPEN_CONNECT_FAILED:
2074 return "connect failed";
2075 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
2076 return "unknown channel type";
2077 case SSH2_OPEN_RESOURCE_SHORTAGE:
2078 return "resource shortage";
2079 }
2080 return "unknown reason";
2081}
2082
2083void
e9a17296 2084channel_input_open_failure(int type, u_int32_t seq, void *ctxt)
3c0ef626 2085{
2086 int id, reason;
2087 char *msg = NULL, *lang = NULL;
2088 Channel *c;
2089
3c0ef626 2090 id = packet_get_int();
2091 c = channel_lookup(id);
2092
2093 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2094 packet_disconnect("Received open failure for "
2095 "non-opening channel %d.", id);
2096 if (compat20) {
2097 reason = packet_get_int();
2098 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
2099 msg = packet_get_string(NULL);
2100 lang = packet_get_string(NULL);
2101 }
0fff78ff 2102 logit("channel %d: open failed: %s%s%s", id,
3c0ef626 2103 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
2104 if (msg != NULL)
2105 xfree(msg);
2106 if (lang != NULL)
2107 xfree(lang);
2108 }
e9a17296 2109 packet_check_eom();
3c0ef626 2110 /* Free the channel. This will also close the socket. */
2111 channel_free(c);
2112}
2113
2114void
e9a17296 2115channel_input_window_adjust(int type, u_int32_t seq, void *ctxt)
3c0ef626 2116{
2117 Channel *c;
680cee3b 2118 int id;
2119 u_int adjust;
3c0ef626 2120
2121 if (!compat20)
2122 return;
2123
2124 /* Get the channel number and verify it. */
2125 id = packet_get_int();
2126 c = channel_lookup(id);
2127
2128 if (c == NULL || c->type != SSH_CHANNEL_OPEN) {
0fff78ff 2129 logit("Received window adjust for "
3c0ef626 2130 "non-open channel %d.", id);
2131 return;
2132 }
2133 adjust = packet_get_int();
e9a17296 2134 packet_check_eom();
680cee3b 2135 debug2("channel %d: rcvd adjust %u", id, adjust);
3c0ef626 2136 c->remote_window += adjust;
2137}
2138
2139void
e9a17296 2140channel_input_port_open(int type, u_int32_t seq, void *ctxt)
3c0ef626 2141{
2142 Channel *c = NULL;
2143 u_short host_port;
2144 char *host, *originator_string;
2145 int remote_id, sock = -1;
2146
2147 remote_id = packet_get_int();
2148 host = packet_get_string(NULL);
2149 host_port = packet_get_int();
2150
2151 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2152 originator_string = packet_get_string(NULL);
2153 } else {
2154 originator_string = xstrdup("unknown (remote did not supply name)");
2155 }
e9a17296 2156 packet_check_eom();
3c0ef626 2157 sock = channel_connect_to(host, host_port);
2158 if (sock != -1) {
2159 c = channel_new("connected socket",
2160 SSH_CHANNEL_CONNECTING, sock, sock, -1, 0, 0, 0,
2161 originator_string, 1);
e9a17296 2162 c->remote_id = remote_id;
3c0ef626 2163 }
0fff78ff 2164 xfree(originator_string);
3c0ef626 2165 if (c == NULL) {
2166 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2167 packet_put_int(remote_id);
2168 packet_send();
2169 }
2170 xfree(host);
2171}
2172
2173
2174/* -- tcp forwarding */
2175
2176void
2177channel_set_af(int af)
2178{
2179 IPv4or6 = af;
2180}
2181
e9a17296 2182static int
2183channel_setup_fwd_listener(int type, const char *listen_addr, u_short listen_port,
2184 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
3c0ef626 2185{
2186 Channel *c;
996d5e62 2187 int sock, r, success = 0, on = 1, wildcard = 0, is_client;
3c0ef626 2188 struct addrinfo hints, *ai, *aitop;
996d5e62 2189 const char *host, *addr;
e9a17296 2190 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
3c0ef626 2191
e9a17296 2192 host = (type == SSH_CHANNEL_RPORT_LISTENER) ?
2193 listen_addr : host_to_connect;
996d5e62 2194 is_client = (type == SSH_CHANNEL_PORT_LISTENER);
3c0ef626 2195
e9a17296 2196 if (host == NULL) {
2197 error("No forward host name.");
2198 return success;
3c0ef626 2199 }
3c0ef626 2200 if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) {
2201 error("Forward host name too long.");
2202 return success;
2203 }
2204
996d5e62 2205 /*
2206 * Determine whether or not a port forward listens to loopback,
dec6d9fe 2207 * specified address or wildcard. On the client, a specified bind
2208 * address will always override gateway_ports. On the server, a
2209 * gateway_ports of 1 (``yes'') will override the client's
2210 * specification and force a wildcard bind, whereas a value of 2
2211 * (``clientspecified'') will bind to whatever address the client
996d5e62 2212 * asked for.
2213 *
2214 * Special-case listen_addrs are:
2215 *
2216 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR
2217 * "" (empty string), "*" -> wildcard v4/v6
2218 * "localhost" -> loopback v4/v6
2219 */
2220 addr = NULL;
2221 if (listen_addr == NULL) {
2222 /* No address specified: default to gateway_ports setting */
2223 if (gateway_ports)
2224 wildcard = 1;
2225 } else if (gateway_ports || is_client) {
2226 if (((datafellows & SSH_OLD_FORWARD_ADDR) &&
2227 strcmp(listen_addr, "0.0.0.0") == 0) ||
2228 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 ||
2229 (!is_client && gateway_ports == 1))
2230 wildcard = 1;
2231 else if (strcmp(listen_addr, "localhost") != 0)
2232 addr = listen_addr;
2233 }
2234
2235 debug3("channel_setup_fwd_listener: type %d wildcard %d addr %s",
2236 type, wildcard, (addr == NULL) ? "NULL" : addr);
2237
3c0ef626 2238 /*
2239 * getaddrinfo returns a loopback address if the hostname is
2240 * set to NULL and hints.ai_flags is not AI_PASSIVE
2241 */
2242 memset(&hints, 0, sizeof(hints));
2243 hints.ai_family = IPv4or6;
996d5e62 2244 hints.ai_flags = wildcard ? AI_PASSIVE : 0;
3c0ef626 2245 hints.ai_socktype = SOCK_STREAM;
2246 snprintf(strport, sizeof strport, "%d", listen_port);
996d5e62 2247 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) {
2248 if (addr == NULL) {
2249 /* This really shouldn't happen */
2250 packet_disconnect("getaddrinfo: fatal error: %s",
2251 gai_strerror(r));
2252 } else {
2253 verbose("channel_setup_fwd_listener: "
2254 "getaddrinfo(%.64s): %s", addr, gai_strerror(r));
2255 packet_send_debug("channel_setup_fwd_listener: "
2256 "getaddrinfo(%.64s): %s", addr, gai_strerror(r));
2257 }
2258 aitop = NULL;
2259 }
3c0ef626 2260
2261 for (ai = aitop; ai; ai = ai->ai_next) {
2262 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2263 continue;
2264 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2265 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
e9a17296 2266 error("channel_setup_fwd_listener: getnameinfo failed");
3c0ef626 2267 continue;
2268 }
2269 /* Create a port to listen for the host. */
0fff78ff 2270 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
3c0ef626 2271 if (sock < 0) {
2272 /* this is no error since kernel may not support ipv6 */
2273 verbose("socket: %.100s", strerror(errno));
2274 continue;
2275 }
2276 /*
41b2f314 2277 * Set socket options.
2278 * Allow local port reuse in TIME_WAIT.
3c0ef626 2279 */
41b2f314 2280 if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &on,
2281 sizeof(on)) == -1)
2282 error("setsockopt SO_REUSEADDR: %s", strerror(errno));
2283
3c0ef626 2284 debug("Local forwarding listening on %s port %s.", ntop, strport);
2285
2286 /* Bind the socket to the address. */
2287 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2288 /* address can be in use ipv6 address is already bound */
2289 if (!ai->ai_next)
2290 error("bind: %.100s", strerror(errno));
2291 else
2292 verbose("bind: %.100s", strerror(errno));
2293
2294 close(sock);
2295 continue;
2296 }
2297 /* Start listening for connections on the socket. */
cdd66111 2298 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
3c0ef626 2299 error("listen: %.100s", strerror(errno));
2300 close(sock);
2301 continue;
2302 }
2303 /* Allocate a channel number for the socket. */
2304 c = channel_new("port listener", type, sock, sock, -1,
2305 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
0fff78ff 2306 0, "port listener", 1);
3c0ef626 2307 strlcpy(c->path, host, sizeof(c->path));
2308 c->host_port = port_to_connect;
2309 c->listening_port = listen_port;
2310 success = 1;
2311 }
2312 if (success == 0)
e9a17296 2313 error("channel_setup_fwd_listener: cannot listen to port: %d",
3c0ef626 2314 listen_port);
2315 freeaddrinfo(aitop);
2316 return success;
2317}
2318
c9f39d2c 2319int
2320channel_cancel_rport_listener(const char *host, u_short port)
2321{
2322 u_int i;
2323 int found = 0;
2324
dec6d9fe 2325 for (i = 0; i < channels_alloc; i++) {
c9f39d2c 2326 Channel *c = channels[i];
2327
2328 if (c != NULL && c->type == SSH_CHANNEL_RPORT_LISTENER &&
2329 strncmp(c->path, host, sizeof(c->path)) == 0 &&
2330 c->listening_port == port) {
996d5e62 2331 debug2("%s: close channel %d", __func__, i);
c9f39d2c 2332 channel_free(c);
2333 found = 1;
2334 }
2335 }
2336
2337 return (found);
2338}
2339
e9a17296 2340/* protocol local port fwd, used by ssh (and sshd in v1) */
2341int
996d5e62 2342channel_setup_local_fwd_listener(const char *listen_host, u_short listen_port,
e9a17296 2343 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2344{
2345 return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER,
996d5e62 2346 listen_host, listen_port, host_to_connect, port_to_connect,
2347 gateway_ports);
e9a17296 2348}
2349
2350/* protocol v2 remote port fwd, used by sshd */
2351int
2352channel_setup_remote_fwd_listener(const char *listen_address,
2353 u_short listen_port, int gateway_ports)
2354{
2355 return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER,
2356 listen_address, listen_port, NULL, 0, gateway_ports);
2357}
2358
3c0ef626 2359/*
2360 * Initiate forwarding of connections to port "port" on remote host through
2361 * the secure channel to host:port from local side.
2362 */
2363
2364void
996d5e62 2365channel_request_remote_forwarding(const char *listen_host, u_short listen_port,
3c0ef626 2366 const char *host_to_connect, u_short port_to_connect)
2367{
e9a17296 2368 int type, success = 0;
3c0ef626 2369
2370 /* Record locally that connection to this host/port is permitted. */
2371 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2372 fatal("channel_request_remote_forwarding: too many forwards");
2373
2374 /* Send the forward request to the remote side. */
2375 if (compat20) {
996d5e62 2376 const char *address_to_bind;
2377 if (listen_host == NULL)
2378 address_to_bind = "localhost";
2379 else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0)
2380 address_to_bind = "";
2381 else
2382 address_to_bind = listen_host;
2383
3c0ef626 2384 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2385 packet_put_cstring("tcpip-forward");
700318f3 2386 packet_put_char(1); /* boolean: want reply */
3c0ef626 2387 packet_put_cstring(address_to_bind);
2388 packet_put_int(listen_port);
2389 packet_send();
2390 packet_write_wait();
2391 /* Assume that server accepts the request */
2392 success = 1;
2393 } else {
2394 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2395 packet_put_int(listen_port);
2396 packet_put_cstring(host_to_connect);
2397 packet_put_int(port_to_connect);
2398 packet_send();
2399 packet_write_wait();
2400
2401 /* Wait for response from the remote side. */
e9a17296 2402 type = packet_read();
3c0ef626 2403 switch (type) {
2404 case SSH_SMSG_SUCCESS:
2405 success = 1;
2406 break;
2407 case SSH_SMSG_FAILURE:
0fff78ff 2408 logit("Warning: Server denied remote port forwarding.");
3c0ef626 2409 break;
2410 default:
2411 /* Unknown packet */
2412 packet_disconnect("Protocol error for port forward request:"
2413 "received packet type %d.", type);
2414 }
2415 }
2416 if (success) {
2417 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2418 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2419 permitted_opens[num_permitted_opens].listen_port = listen_port;
2420 num_permitted_opens++;
2421 }
2422}
2423
c9f39d2c 2424/*
2425 * Request cancellation of remote forwarding of connection host:port from
2426 * local side.
2427 */
2428void
996d5e62 2429channel_request_rforward_cancel(const char *host, u_short port)
c9f39d2c 2430{
2431 int i;
c9f39d2c 2432
2433 if (!compat20)
2434 return;
2435
2436 for (i = 0; i < num_permitted_opens; i++) {
2437 if (permitted_opens[i].host_to_connect != NULL &&
2438 permitted_opens[i].listen_port == port)
2439 break;
2440 }
2441 if (i >= num_permitted_opens) {
2442 debug("%s: requested forward not found", __func__);
2443 return;
2444 }
2445 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2446 packet_put_cstring("cancel-tcpip-forward");
2447 packet_put_char(0);
996d5e62 2448 packet_put_cstring(host == NULL ? "" : host);
c9f39d2c 2449 packet_put_int(port);
2450 packet_send();
2451
2452 permitted_opens[i].listen_port = 0;
2453 permitted_opens[i].port_to_connect = 0;
2454 free(permitted_opens[i].host_to_connect);
2455 permitted_opens[i].host_to_connect = NULL;
2456}
2457
3c0ef626 2458/*
2459 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
2460 * listening for the port, and sends back a success reply (or disconnect
2461 * message if there was an error). This never returns if there was an error.
2462 */
2463
2464void
2465channel_input_port_forward_request(int is_root, int gateway_ports)
2466{
2467 u_short port, host_port;
2468 char *hostname;
2469
2470 /* Get arguments from the packet. */
2471 port = packet_get_int();
2472 hostname = packet_get_string(NULL);
2473 host_port = packet_get_int();
2474
2475#ifndef HAVE_CYGWIN
2476 /*
2477 * Check that an unprivileged user is not trying to forward a
2478 * privileged port.
2479 */
2480 if (port < IPPORT_RESERVED && !is_root)
0fff78ff 2481 packet_disconnect(
2482 "Requested forwarding of port %d but user is not root.",
2483 port);
2484 if (host_port == 0)
2485 packet_disconnect("Dynamic forwarding denied.");
3c0ef626 2486#endif
0fff78ff 2487
3c0ef626 2488 /* Initiate forwarding */
996d5e62 2489 channel_setup_local_fwd_listener(NULL, port, hostname,
2490 host_port, gateway_ports);
3c0ef626 2491
2492 /* Free the argument string. */
2493 xfree(hostname);
2494}
2495
2496/*
2497 * Permits opening to any host/port if permitted_opens[] is empty. This is
2498 * usually called by the server, because the user could connect to any port
2499 * anyway, and the server has no way to know but to trust the client anyway.
2500 */
2501void
e9a17296 2502channel_permit_all_opens(void)
3c0ef626 2503{
2504 if (num_permitted_opens == 0)
2505 all_opens_permitted = 1;
2506}
2507
2508void
2509channel_add_permitted_opens(char *host, int port)
2510{
2511 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2512 fatal("channel_request_remote_forwarding: too many forwards");
2513 debug("allow port forwarding to host %s port %d", host, port);
2514
2515 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
2516 permitted_opens[num_permitted_opens].port_to_connect = port;
2517 num_permitted_opens++;
2518
2519 all_opens_permitted = 0;
2520}
2521
2522void
2523channel_clear_permitted_opens(void)
2524{
2525 int i;
2526
2527 for (i = 0; i < num_permitted_opens; i++)
c9f39d2c 2528 if (permitted_opens[i].host_to_connect != NULL)
2529 xfree(permitted_opens[i].host_to_connect);
3c0ef626 2530 num_permitted_opens = 0;
2531
2532}
2533
2534
2535/* return socket to remote host, port */
2536static int
2537connect_to(const char *host, u_short port)
2538{
2539 struct addrinfo hints, *ai, *aitop;
2540 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2541 int gaierr;
2542 int sock = -1;
2543
2544 memset(&hints, 0, sizeof(hints));
2545 hints.ai_family = IPv4or6;
2546 hints.ai_socktype = SOCK_STREAM;
2547 snprintf(strport, sizeof strport, "%d", port);
2548 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
2549 error("connect_to %.100s: unknown host (%s)", host,
2550 gai_strerror(gaierr));
2551 return -1;
2552 }
2553 for (ai = aitop; ai; ai = ai->ai_next) {
2554 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2555 continue;
2556 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2557 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2558 error("connect_to: getnameinfo failed");
2559 continue;
2560 }
0fff78ff 2561 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
3c0ef626 2562 if (sock < 0) {
6a9b3198 2563 if (ai->ai_next == NULL)
2564 error("socket: %.100s", strerror(errno));
2565 else
2566 verbose("socket: %.100s", strerror(errno));
3c0ef626 2567 continue;
2568 }
c9f39d2c 2569 if (set_nonblock(sock) == -1)
2570 fatal("%s: set_nonblock(%d)", __func__, sock);
3c0ef626 2571 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 &&
2572 errno != EINPROGRESS) {
2573 error("connect_to %.100s port %s: %.100s", ntop, strport,
2574 strerror(errno));
2575 close(sock);
2576 continue; /* fail -- try next */
2577 }
2578 break; /* success */
2579
2580 }
2581 freeaddrinfo(aitop);
2582 if (!ai) {
2583 error("connect_to %.100s port %d: failed.", host, port);
2584 return -1;
2585 }
2586 /* success */
e9a17296 2587 set_nodelay(sock);
3c0ef626 2588 return sock;
2589}
2590
2591int
2592channel_connect_by_listen_address(u_short listen_port)
2593{
2594 int i;
2595
2596 for (i = 0; i < num_permitted_opens; i++)
c9f39d2c 2597 if (permitted_opens[i].host_to_connect != NULL &&
2598 permitted_opens[i].listen_port == listen_port)
3c0ef626 2599 return connect_to(
2600 permitted_opens[i].host_to_connect,
2601 permitted_opens[i].port_to_connect);
2602 error("WARNING: Server requests forwarding for unknown listen_port %d",
2603 listen_port);
2604 return -1;
2605}
2606
2607/* Check if connecting to that port is permitted and connect. */
2608int
2609channel_connect_to(const char *host, u_short port)
2610{
2611 int i, permit;
2612
2613 permit = all_opens_permitted;
2614 if (!permit) {
2615 for (i = 0; i < num_permitted_opens; i++)
c9f39d2c 2616 if (permitted_opens[i].host_to_connect != NULL &&
2617 permitted_opens[i].port_to_connect == port &&
3c0ef626 2618 strcmp(permitted_opens[i].host_to_connect, host) == 0)
2619 permit = 1;
2620
2621 }
2622 if (!permit) {
0fff78ff 2623 logit("Received request to connect to host %.100s port %d, "
3c0ef626 2624 "but the request was denied.", host, port);
2625 return -1;
2626 }
2627 return connect_to(host, port);
2628}
2629
c9f39d2c 2630void
2631channel_send_window_changes(void)
2632{
2633 u_int i;
2634 struct winsize ws;
2635
2636 for (i = 0; i < channels_alloc; i++) {
dec6d9fe 2637 if (channels[i] == NULL || !channels[i]->client_tty ||
c9f39d2c 2638 channels[i]->type != SSH_CHANNEL_OPEN)
2639 continue;
2640 if (ioctl(channels[i]->rfd, TIOCGWINSZ, &ws) < 0)
2641 continue;
2642 channel_request_start(i, "window-change", 0);
2643 packet_put_int(ws.ws_col);
2644 packet_put_int(ws.ws_row);
2645 packet_put_int(ws.ws_xpixel);
2646 packet_put_int(ws.ws_ypixel);
2647 packet_send();
2648 }
2649}
2650
3c0ef626 2651/* -- X11 forwarding */
2652
2653/*
2654 * Creates an internet domain socket for listening for X11 connections.
680cee3b 2655 * Returns 0 and a suitable display number for the DISPLAY variable
2656 * stored in display_numberp , or -1 if an error occurs.
3c0ef626 2657 */
e9a17296 2658int
2659x11_create_display_inet(int x11_display_offset, int x11_use_localhost,
680cee3b 2660 int single_connection, u_int *display_numberp)
3c0ef626 2661{
e9a17296 2662 Channel *nc = NULL;
3c0ef626 2663 int display_number, sock;
2664 u_short port;
2665 struct addrinfo hints, *ai, *aitop;
2666 char strport[NI_MAXSERV];
2667 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
3c0ef626 2668
2669 for (display_number = x11_display_offset;
e9a17296 2670 display_number < MAX_DISPLAYS;
2671 display_number++) {
3c0ef626 2672 port = 6000 + display_number;
2673 memset(&hints, 0, sizeof(hints));
2674 hints.ai_family = IPv4or6;
e9a17296 2675 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE;
3c0ef626 2676 hints.ai_socktype = SOCK_STREAM;
2677 snprintf(strport, sizeof strport, "%d", port);
2678 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
2679 error("getaddrinfo: %.100s", gai_strerror(gaierr));
e9a17296 2680 return -1;
3c0ef626 2681 }
2682 for (ai = aitop; ai; ai = ai->ai_next) {
2683 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2684 continue;
0fff78ff 2685 sock = socket(ai->ai_family, ai->ai_socktype,
2686 ai->ai_protocol);
3c0ef626 2687 if (sock < 0) {
2688 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
2689 error("socket: %.100s", strerror(errno));
c9f39d2c 2690 freeaddrinfo(aitop);
e9a17296 2691 return -1;
3c0ef626 2692 } else {
2693 debug("x11_create_display_inet: Socket family %d not supported",
2694 ai->ai_family);
2695 continue;
2696 }
2697 }
f5799ae1 2698#ifdef IPV6_V6ONLY
2699 if (ai->ai_family == AF_INET6) {
2700 int on = 1;
2701 if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) < 0)
2702 error("setsockopt IPV6_V6ONLY: %.100s", strerror(errno));
2703 }
2704#endif
3c0ef626 2705 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
0fff78ff 2706 debug2("bind port %d: %.100s", port, strerror(errno));
3c0ef626 2707 close(sock);
2708
2709 if (ai->ai_next)
2710 continue;
2711
2712 for (n = 0; n < num_socks; n++) {
3c0ef626 2713 close(socks[n]);
2714 }
2715 num_socks = 0;
2716 break;
2717 }
2718 socks[num_socks++] = sock;
2719#ifndef DONT_TRY_OTHER_AF
2720 if (num_socks == NUM_SOCKS)
2721 break;
2722#else
f5799ae1 2723 if (x11_use_localhost) {
2724 if (num_socks == NUM_SOCKS)
2725 break;
2726 } else {
2727 break;
2728 }
3c0ef626 2729#endif
2730 }
2731 freeaddrinfo(aitop);
2732 if (num_socks > 0)
2733 break;
2734 }
2735 if (display_number >= MAX_DISPLAYS) {
2736 error("Failed to allocate internet-domain X11 display socket.");
e9a17296 2737 return -1;
3c0ef626 2738 }
2739 /* Start listening for connections on the socket. */
2740 for (n = 0; n < num_socks; n++) {
2741 sock = socks[n];
cdd66111 2742 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
3c0ef626 2743 error("listen: %.100s", strerror(errno));
3c0ef626 2744 close(sock);
e9a17296 2745 return -1;
3c0ef626 2746 }
3c0ef626 2747 }
3c0ef626 2748
2749 /* Allocate a channel for each socket. */
2750 for (n = 0; n < num_socks; n++) {
2751 sock = socks[n];
e9a17296 2752 nc = channel_new("x11 listener",
3c0ef626 2753 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
2754 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
0fff78ff 2755 0, "X11 inet listener", 1);
e9a17296 2756 nc->single_connection = single_connection;
3c0ef626 2757 }
2758
e9a17296 2759 /* Return the display number for the DISPLAY environment variable. */
680cee3b 2760 *display_numberp = display_number;
2761 return (0);
3c0ef626 2762}
2763
3c0ef626 2764static int
2765connect_local_xsocket(u_int dnr)
2766{
3c0ef626 2767 int sock;
2768 struct sockaddr_un addr;
3c0ef626 2769
e9a17296 2770 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2771 if (sock < 0)
2772 error("socket: %.100s", strerror(errno));
2773 memset(&addr, 0, sizeof(addr));
2774 addr.sun_family = AF_UNIX;
2775 snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr);
2776 if (connect(sock, (struct sockaddr *) & addr, sizeof(addr)) == 0)
2777 return sock;
2778 close(sock);
3c0ef626 2779 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
2780 return -1;
2781}
2782
2783int
2784x11_connect_display(void)
2785{
2786 int display_number, sock = 0;
2787 const char *display;
2788 char buf[1024], *cp;
2789 struct addrinfo hints, *ai, *aitop;
2790 char strport[NI_MAXSERV];
2791 int gaierr;
2792
2793 /* Try to open a socket for the local X server. */
2794 display = getenv("DISPLAY");
2795 if (!display) {
2796 error("DISPLAY not set.");
2797 return -1;
2798 }
2799 /*
2800 * Now we decode the value of the DISPLAY variable and make a
2801 * connection to the real X server.
2802 */
2803
2804 /*
2805 * Check if it is a unix domain socket. Unix domain displays are in
2806 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
2807 */
2808 if (strncmp(display, "unix:", 5) == 0 ||
2809 display[0] == ':') {
2810 /* Connect to the unix domain socket. */
2811 if (sscanf(strrchr(display, ':') + 1, "%d", &display_number) != 1) {
2812 error("Could not parse display number from DISPLAY: %.100s",
e9a17296 2813 display);
3c0ef626 2814 return -1;
2815 }
2816 /* Create a socket. */
2817 sock = connect_local_xsocket(display_number);
2818 if (sock < 0)
2819 return -1;
2820
2821 /* OK, we now have a connection to the display. */
2822 return sock;
2823 }
2824 /*
2825 * Connect to an inet socket. The DISPLAY value is supposedly
2826 * hostname:d[.s], where hostname may also be numeric IP address.
2827 */
e9a17296 2828 strlcpy(buf, display, sizeof(buf));
3c0ef626 2829 cp = strchr(buf, ':');
2830 if (!cp) {
2831 error("Could not find ':' in DISPLAY: %.100s", display);
2832 return -1;
2833 }
2834 *cp = 0;
2835 /* buf now contains the host name. But first we parse the display number. */
2836 if (sscanf(cp + 1, "%d", &display_number) != 1) {
2837 error("Could not parse display number from DISPLAY: %.100s",
e9a17296 2838 display);
3c0ef626 2839 return -1;
2840 }
2841
2842 /* Look up the host address */
2843 memset(&hints, 0, sizeof(hints));
2844 hints.ai_family = IPv4or6;
2845 hints.ai_socktype = SOCK_STREAM;
2846 snprintf(strport, sizeof strport, "%d", 6000 + display_number);
2847 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
2848 error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr));
2849 return -1;
2850 }
2851 for (ai = aitop; ai; ai = ai->ai_next) {
2852 /* Create a socket. */
0fff78ff 2853 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
3c0ef626 2854 if (sock < 0) {
0fff78ff 2855 debug2("socket: %.100s", strerror(errno));
3c0ef626 2856 continue;
2857 }
2858 /* Connect it to the display. */
2859 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
0fff78ff 2860 debug2("connect %.100s port %d: %.100s", buf,
3c0ef626 2861 6000 + display_number, strerror(errno));
2862 close(sock);
2863 continue;
2864 }
2865 /* Success */
2866 break;
2867 }
2868 freeaddrinfo(aitop);
2869 if (!ai) {
2870 error("connect %.100s port %d: %.100s", buf, 6000 + display_number,
2871 strerror(errno));
2872 return -1;
2873 }
e9a17296 2874 set_nodelay(sock);
3c0ef626 2875 return sock;
2876}
2877
2878/*
2879 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
2880 * the remote channel number. We should do whatever we want, and respond
2881 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
2882 */
2883
2884void
e9a17296 2885x11_input_open(int type, u_int32_t seq, void *ctxt)
3c0ef626 2886{
2887 Channel *c = NULL;
2888 int remote_id, sock = 0;
2889 char *remote_host;
2890
2891 debug("Received X11 open request.");
2892
2893 remote_id = packet_get_int();
2894
2895 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2896 remote_host = packet_get_string(NULL);
2897 } else {
2898 remote_host = xstrdup("unknown (remote did not supply name)");
2899 }
e9a17296 2900 packet_check_eom();
3c0ef626 2901
2902 /* Obtain a connection to the real X display. */
2903 sock = x11_connect_display();
2904 if (sock != -1) {
2905 /* Allocate a channel for this connection. */
2906 c = channel_new("connected x11 socket",
2907 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
2908 remote_host, 1);
e9a17296 2909 c->remote_id = remote_id;
2910 c->force_drain = 1;
3c0ef626 2911 }
0fff78ff 2912 xfree(remote_host);
3c0ef626 2913 if (c == NULL) {
2914 /* Send refusal to the remote host. */
2915 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2916 packet_put_int(remote_id);
2917 } else {
2918 /* Send a confirmation to the remote host. */
2919 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2920 packet_put_int(remote_id);
2921 packet_put_int(c->self);
2922 }
2923 packet_send();
2924}
2925
2926/* dummy protocol handler that denies SSH-1 requests (agent/x11) */
2927void
e9a17296 2928deny_input_open(int type, u_int32_t seq, void *ctxt)
3c0ef626 2929{
2930 int rchan = packet_get_int();
41b2f314 2931
e9a17296 2932 switch (type) {
3c0ef626 2933 case SSH_SMSG_AGENT_OPEN:
2934 error("Warning: ssh server tried agent forwarding.");
2935 break;
2936 case SSH_SMSG_X11_OPEN:
2937 error("Warning: ssh server tried X11 forwarding.");
2938 break;
2939 default:
e9a17296 2940 error("deny_input_open: type %d", type);
3c0ef626 2941 break;
2942 }
2943 error("Warning: this is probably a break in attempt by a malicious server.");
2944 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2945 packet_put_int(rchan);
2946 packet_send();
2947}
2948
2949/*
2950 * Requests forwarding of X11 connections, generates fake authentication
2951 * data, and enables authentication spoofing.
2952 * This should be called in the client only.
2953 */
2954void
2955x11_request_forwarding_with_spoofing(int client_session_id,
2956 const char *proto, const char *data)
2957{
2958 u_int data_len = (u_int) strlen(data) / 2;
2959 u_int i, value, len;
2960 char *new_data;
2961 int screen_number;
2962 const char *cp;
c9f39d2c 2963 u_int32_t rnd = 0;
3c0ef626 2964
2965 cp = getenv("DISPLAY");
2966 if (cp)
2967 cp = strchr(cp, ':');
2968 if (cp)
2969 cp = strchr(cp, '.');
2970 if (cp)
2971 screen_number = atoi(cp + 1);
2972 else
2973 screen_number = 0;
2974
2975 /* Save protocol name. */
2976 x11_saved_proto = xstrdup(proto);
2977
2978 /*
2979 * Extract real authentication data and generate fake data of the
2980 * same length.
2981 */
2982 x11_saved_data = xmalloc(data_len);
2983 x11_fake_data = xmalloc(data_len);
2984 for (i = 0; i < data_len; i++) {
2985 if (sscanf(data + 2 * i, "%2x", &value) != 1)
2986 fatal("x11_request_forwarding: bad authentication data: %.100s", data);
2987 if (i % 4 == 0)
c9f39d2c 2988 rnd = arc4random();
3c0ef626 2989 x11_saved_data[i] = value;
c9f39d2c 2990 x11_fake_data[i] = rnd & 0xff;
2991 rnd >>= 8;
3c0ef626 2992 }
2993 x11_saved_data_len = data_len;
2994 x11_fake_data_len = data_len;
2995
2996 /* Convert the fake data into hex. */
2997 len = 2 * data_len + 1;
2998 new_data = xmalloc(len);
2999 for (i = 0; i < data_len; i++)
3000 snprintf(new_data + 2 * i, len - 2 * i,
3001 "%02x", (u_char) x11_fake_data[i]);
3002
3003 /* Send the request packet. */
3004 if (compat20) {
3005 channel_request_start(client_session_id, "x11-req", 0);
3006 packet_put_char(0); /* XXX bool single connection */
3007 } else {
3008 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
3009 }
3010 packet_put_cstring(proto);
3011 packet_put_cstring(new_data);
3012 packet_put_int(screen_number);
3013 packet_send();
3014 packet_write_wait();
3015 xfree(new_data);
3016}
3017
3018
3019/* -- agent forwarding */
3020
3021/* Sends a message to the server to request authentication fd forwarding. */
3022
3023void
e9a17296 3024auth_request_forwarding(void)
3c0ef626 3025{
3026 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
3027 packet_send();
3028 packet_write_wait();
3029}
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