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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"
700318f3 42RCSID("$OpenBSD: channels.c,v 1.173 2002/04/22 21:04:52 markus Exp $");
3c0ef626 43
44#include "ssh.h"
45#include "ssh1.h"
46#include "ssh2.h"
47#include "packet.h"
48#include "xmalloc.h"
49#include "uidswap.h"
50#include "log.h"
51#include "misc.h"
52#include "channels.h"
53#include "compat.h"
54#include "canohost.h"
55#include "key.h"
56#include "authfd.h"
e9a17296 57#include "pathnames.h"
3c0ef626 58
59
60/* -- channel core */
61
62/*
63 * Pointer to an array containing all allocated channels. The array is
64 * dynamically extended as needed.
65 */
66static Channel **channels = NULL;
67
68/*
69 * Size of the channel array. All slots of the array must always be
70 * initialized (at least the type field); unused slots set to NULL
71 */
72static int channels_alloc = 0;
73
74/*
75 * Maximum file descriptor value used in any of the channels. This is
76 * updated in channel_new.
77 */
78static int channel_max_fd = 0;
79
80
81/* -- tcp forwarding */
82
83/*
84 * Data structure for storing which hosts are permitted for forward requests.
85 * The local sides of any remote forwards are stored in this array to prevent
86 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local
87 * network (which might be behind a firewall).
88 */
89typedef struct {
90 char *host_to_connect; /* Connect to 'host'. */
91 u_short port_to_connect; /* Connect to 'port'. */
92 u_short listen_port; /* Remote side should listen port number. */
93} ForwardPermission;
94
95/* List of all permitted host/port pairs to connect. */
96static ForwardPermission permitted_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
97
98/* Number of permitted host/port pairs in the array. */
99static int num_permitted_opens = 0;
100/*
101 * If this is true, all opens are permitted. This is the case on the server
102 * on which we have to trust the client anyway, and the user could do
103 * anything after logging in anyway.
104 */
105static int all_opens_permitted = 0;
106
107
108/* -- X11 forwarding */
109
110/* Maximum number of fake X11 displays to try. */
111#define MAX_DISPLAYS 1000
112
113/* Saved X11 authentication protocol name. */
114static char *x11_saved_proto = NULL;
115
116/* Saved X11 authentication data. This is the real data. */
117static char *x11_saved_data = NULL;
118static u_int x11_saved_data_len = 0;
119
120/*
121 * Fake X11 authentication data. This is what the server will be sending us;
122 * we should replace any occurrences of this by the real data.
123 */
124static char *x11_fake_data = NULL;
125static u_int x11_fake_data_len;
126
127
128/* -- agent forwarding */
129
130#define NUM_SOCKS 10
131
132/* Name and directory of socket for authentication agent forwarding. */
133static char *auth_sock_name = NULL;
134static char *auth_sock_dir = NULL;
135
136/* AF_UNSPEC or AF_INET or AF_INET6 */
137static int IPv4or6 = AF_UNSPEC;
138
139/* helper */
140static void port_open_helper(Channel *c, char *rtype);
141
142/* -- channel core */
143
144Channel *
145channel_lookup(int id)
146{
147 Channel *c;
148
e9a17296 149 if (id < 0 || id >= channels_alloc) {
3c0ef626 150 log("channel_lookup: %d: bad id", id);
151 return NULL;
152 }
153 c = channels[id];
154 if (c == NULL) {
155 log("channel_lookup: %d: bad id: channel free", id);
156 return NULL;
157 }
158 return c;
159}
160
161/*
162 * Register filedescriptors for a channel, used when allocating a channel or
163 * when the channel consumer/producer is ready, e.g. shell exec'd
164 */
165
166static void
167channel_register_fds(Channel *c, int rfd, int wfd, int efd,
168 int extusage, int nonblock)
169{
170 /* Update the maximum file descriptor value. */
171 channel_max_fd = MAX(channel_max_fd, rfd);
172 channel_max_fd = MAX(channel_max_fd, wfd);
173 channel_max_fd = MAX(channel_max_fd, efd);
174
175 /* XXX set close-on-exec -markus */
176
177 c->rfd = rfd;
178 c->wfd = wfd;
179 c->sock = (rfd == wfd) ? rfd : -1;
180 c->efd = efd;
181 c->extended_usage = extusage;
182
183 /* XXX ugly hack: nonblock is only set by the server */
184 if (nonblock && isatty(c->rfd)) {
185 debug("channel %d: rfd %d isatty", c->self, c->rfd);
186 c->isatty = 1;
187 if (!isatty(c->wfd)) {
188 error("channel %d: wfd %d is not a tty?",
189 c->self, c->wfd);
190 }
191 } else {
192 c->isatty = 0;
193 }
194
195 /* enable nonblocking mode */
196 if (nonblock) {
197 if (rfd != -1)
198 set_nonblock(rfd);
199 if (wfd != -1)
200 set_nonblock(wfd);
201 if (efd != -1)
202 set_nonblock(efd);
203 }
204}
205
206/*
207 * Allocate a new channel object and set its type and socket. This will cause
208 * remote_name to be freed.
209 */
210
211Channel *
212channel_new(char *ctype, int type, int rfd, int wfd, int efd,
213 int window, int maxpack, int extusage, char *remote_name, int nonblock)
214{
215 int i, found;
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;
224 fatal_add_cleanup((void (*) (void *)) channel_free_all, NULL);
225 }
226 /* Try to find a free slot where to put the new channel. */
227 for (found = -1, i = 0; i < channels_alloc; i++)
228 if (channels[i] == NULL) {
229 /* Found a free slot. */
230 found = i;
231 break;
232 }
233 if (found == -1) {
234 /* There are no free slots. Take last+1 slot and expand the array. */
235 found = channels_alloc;
236 channels_alloc += 10;
237 debug2("channel: expanding %d", channels_alloc);
238 channels = xrealloc(channels, channels_alloc * sizeof(Channel *));
239 for (i = found; i < channels_alloc; i++)
240 channels[i] = NULL;
241 }
242 /* Initialize and return new channel. */
243 c = channels[found] = xmalloc(sizeof(Channel));
244 memset(c, 0, sizeof(Channel));
245 buffer_init(&c->input);
246 buffer_init(&c->output);
247 buffer_init(&c->extended);
e9a17296 248 c->ostate = CHAN_OUTPUT_OPEN;
249 c->istate = CHAN_INPUT_OPEN;
250 c->flags = 0;
3c0ef626 251 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
252 c->self = found;
253 c->type = type;
254 c->ctype = ctype;
255 c->local_window = window;
256 c->local_window_max = window;
257 c->local_consumed = 0;
258 c->local_maxpacket = maxpack;
259 c->remote_id = -1;
260 c->remote_name = remote_name;
261 c->remote_window = 0;
262 c->remote_maxpacket = 0;
3c0ef626 263 c->force_drain = 0;
e9a17296 264 c->single_connection = 0;
3c0ef626 265 c->detach_user = NULL;
e9a17296 266 c->confirm = NULL;
3c0ef626 267 c->input_filter = NULL;
268 debug("channel %d: new [%s]", found, remote_name);
269 return c;
270}
271
272static int
273channel_find_maxfd(void)
274{
275 int i, max = 0;
276 Channel *c;
277
278 for (i = 0; i < channels_alloc; i++) {
279 c = channels[i];
280 if (c != NULL) {
281 max = MAX(max, c->rfd);
282 max = MAX(max, c->wfd);
283 max = MAX(max, c->efd);
284 }
285 }
286 return max;
287}
288
289int
290channel_close_fd(int *fdp)
291{
292 int ret = 0, fd = *fdp;
293
294 if (fd != -1) {
295 ret = close(fd);
296 *fdp = -1;
297 if (fd == channel_max_fd)
298 channel_max_fd = channel_find_maxfd();
299 }
300 return ret;
301}
302
303/* Close all channel fd/socket. */
304
305static void
306channel_close_fds(Channel *c)
307{
308 debug3("channel_close_fds: channel %d: r %d w %d e %d",
309 c->self, c->rfd, c->wfd, c->efd);
310
311 channel_close_fd(&c->sock);
312 channel_close_fd(&c->rfd);
313 channel_close_fd(&c->wfd);
314 channel_close_fd(&c->efd);
315}
316
317/* Free the channel and close its fd/socket. */
318
319void
320channel_free(Channel *c)
321{
322 char *s;
323 int i, n;
324
325 for (n = 0, i = 0; i < channels_alloc; i++)
326 if (channels[i])
327 n++;
328 debug("channel_free: channel %d: %s, nchannels %d", c->self,
329 c->remote_name ? c->remote_name : "???", n);
330
331 s = channel_open_message();
332 debug3("channel_free: status: %s", s);
333 xfree(s);
334
335 if (c->sock != -1)
336 shutdown(c->sock, SHUT_RDWR);
337 channel_close_fds(c);
338 buffer_free(&c->input);
339 buffer_free(&c->output);
340 buffer_free(&c->extended);
341 if (c->remote_name) {
342 xfree(c->remote_name);
343 c->remote_name = NULL;
344 }
345 channels[c->self] = NULL;
346 xfree(c);
347}
348
349void
350channel_free_all(void)
351{
352 int i;
353
354 for (i = 0; i < channels_alloc; i++)
355 if (channels[i] != NULL)
356 channel_free(channels[i]);
357}
358
359/*
360 * Closes the sockets/fds of all channels. This is used to close extra file
361 * descriptors after a fork.
362 */
363
364void
e9a17296 365channel_close_all(void)
3c0ef626 366{
367 int i;
368
369 for (i = 0; i < channels_alloc; i++)
370 if (channels[i] != NULL)
371 channel_close_fds(channels[i]);
372}
373
374/*
375 * Stop listening to channels.
376 */
377
378void
379channel_stop_listening(void)
380{
381 int i;
382 Channel *c;
383
384 for (i = 0; i < channels_alloc; i++) {
385 c = channels[i];
386 if (c != NULL) {
387 switch (c->type) {
388 case SSH_CHANNEL_AUTH_SOCKET:
389 case SSH_CHANNEL_PORT_LISTENER:
390 case SSH_CHANNEL_RPORT_LISTENER:
391 case SSH_CHANNEL_X11_LISTENER:
392 channel_close_fd(&c->sock);
393 channel_free(c);
394 break;
395 }
396 }
397 }
398}
399
400/*
401 * Returns true if no channel has too much buffered data, and false if one or
402 * more channel is overfull.
403 */
404
405int
e9a17296 406channel_not_very_much_buffered_data(void)
3c0ef626 407{
408 u_int i;
409 Channel *c;
410
411 for (i = 0; i < channels_alloc; i++) {
412 c = channels[i];
413 if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
414#if 0
415 if (!compat20 &&
416 buffer_len(&c->input) > packet_get_maxsize()) {
417 debug("channel %d: big input buffer %d",
418 c->self, buffer_len(&c->input));
419 return 0;
420 }
421#endif
422 if (buffer_len(&c->output) > packet_get_maxsize()) {
423 debug("channel %d: big output buffer %d > %d",
424 c->self, buffer_len(&c->output),
425 packet_get_maxsize());
426 return 0;
427 }
428 }
429 }
430 return 1;
431}
432
433/* Returns true if any channel is still open. */
434
435int
e9a17296 436channel_still_open(void)
3c0ef626 437{
438 int i;
439 Channel *c;
440
441 for (i = 0; i < channels_alloc; i++) {
442 c = channels[i];
443 if (c == NULL)
444 continue;
445 switch (c->type) {
446 case SSH_CHANNEL_X11_LISTENER:
447 case SSH_CHANNEL_PORT_LISTENER:
448 case SSH_CHANNEL_RPORT_LISTENER:
449 case SSH_CHANNEL_CLOSED:
450 case SSH_CHANNEL_AUTH_SOCKET:
451 case SSH_CHANNEL_DYNAMIC:
452 case SSH_CHANNEL_CONNECTING:
453 case SSH_CHANNEL_ZOMBIE:
454 continue;
455 case SSH_CHANNEL_LARVAL:
456 if (!compat20)
457 fatal("cannot happen: SSH_CHANNEL_LARVAL");
458 continue;
459 case SSH_CHANNEL_OPENING:
460 case SSH_CHANNEL_OPEN:
461 case SSH_CHANNEL_X11_OPEN:
462 return 1;
463 case SSH_CHANNEL_INPUT_DRAINING:
464 case SSH_CHANNEL_OUTPUT_DRAINING:
465 if (!compat13)
466 fatal("cannot happen: OUT_DRAIN");
467 return 1;
468 default:
469 fatal("channel_still_open: bad channel type %d", c->type);
470 /* NOTREACHED */
471 }
472 }
473 return 0;
474}
475
476/* Returns the id of an open channel suitable for keepaliving */
477
478int
e9a17296 479channel_find_open(void)
3c0ef626 480{
481 int i;
482 Channel *c;
483
484 for (i = 0; i < channels_alloc; i++) {
485 c = channels[i];
486 if (c == NULL)
487 continue;
488 switch (c->type) {
489 case SSH_CHANNEL_CLOSED:
490 case SSH_CHANNEL_DYNAMIC:
491 case SSH_CHANNEL_X11_LISTENER:
492 case SSH_CHANNEL_PORT_LISTENER:
493 case SSH_CHANNEL_RPORT_LISTENER:
494 case SSH_CHANNEL_OPENING:
495 case SSH_CHANNEL_CONNECTING:
496 case SSH_CHANNEL_ZOMBIE:
497 continue;
498 case SSH_CHANNEL_LARVAL:
499 case SSH_CHANNEL_AUTH_SOCKET:
500 case SSH_CHANNEL_OPEN:
501 case SSH_CHANNEL_X11_OPEN:
502 return i;
503 case SSH_CHANNEL_INPUT_DRAINING:
504 case SSH_CHANNEL_OUTPUT_DRAINING:
505 if (!compat13)
506 fatal("cannot happen: OUT_DRAIN");
507 return i;
508 default:
509 fatal("channel_find_open: bad channel type %d", c->type);
510 /* NOTREACHED */
511 }
512 }
513 return -1;
514}
515
516
517/*
518 * Returns a message describing the currently open forwarded connections,
519 * suitable for sending to the client. The message contains crlf pairs for
520 * newlines.
521 */
522
523char *
e9a17296 524channel_open_message(void)
3c0ef626 525{
526 Buffer buffer;
527 Channel *c;
528 char buf[1024], *cp;
529 int i;
530
531 buffer_init(&buffer);
532 snprintf(buf, sizeof buf, "The following connections are open:\r\n");
533 buffer_append(&buffer, buf, strlen(buf));
534 for (i = 0; i < channels_alloc; i++) {
535 c = channels[i];
536 if (c == NULL)
537 continue;
538 switch (c->type) {
539 case SSH_CHANNEL_X11_LISTENER:
540 case SSH_CHANNEL_PORT_LISTENER:
541 case SSH_CHANNEL_RPORT_LISTENER:
542 case SSH_CHANNEL_CLOSED:
543 case SSH_CHANNEL_AUTH_SOCKET:
544 case SSH_CHANNEL_ZOMBIE:
545 continue;
546 case SSH_CHANNEL_LARVAL:
547 case SSH_CHANNEL_OPENING:
548 case SSH_CHANNEL_CONNECTING:
549 case SSH_CHANNEL_DYNAMIC:
550 case SSH_CHANNEL_OPEN:
551 case SSH_CHANNEL_X11_OPEN:
552 case SSH_CHANNEL_INPUT_DRAINING:
553 case SSH_CHANNEL_OUTPUT_DRAINING:
554 snprintf(buf, sizeof buf, " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d)\r\n",
555 c->self, c->remote_name,
556 c->type, c->remote_id,
557 c->istate, buffer_len(&c->input),
558 c->ostate, buffer_len(&c->output),
559 c->rfd, c->wfd);
560 buffer_append(&buffer, buf, strlen(buf));
561 continue;
562 default:
563 fatal("channel_open_message: bad channel type %d", c->type);
564 /* NOTREACHED */
565 }
566 }
567 buffer_append(&buffer, "\0", 1);
568 cp = xstrdup(buffer_ptr(&buffer));
569 buffer_free(&buffer);
570 return cp;
571}
572
573void
574channel_send_open(int id)
575{
576 Channel *c = channel_lookup(id);
577 if (c == NULL) {
578 log("channel_send_open: %d: bad id", id);
579 return;
580 }
581 debug("send channel open %d", id);
582 packet_start(SSH2_MSG_CHANNEL_OPEN);
583 packet_put_cstring(c->ctype);
584 packet_put_int(c->self);
585 packet_put_int(c->local_window);
586 packet_put_int(c->local_maxpacket);
587 packet_send();
588}
589
590void
e9a17296 591channel_request_start(int local_id, char *service, int wantconfirm)
3c0ef626 592{
e9a17296 593 Channel *c = channel_lookup(local_id);
3c0ef626 594 if (c == NULL) {
e9a17296 595 log("channel_request_start: %d: unknown channel id", local_id);
3c0ef626 596 return;
597 }
e9a17296 598 debug("channel request %d: %s", local_id, service) ;
3c0ef626 599 packet_start(SSH2_MSG_CHANNEL_REQUEST);
600 packet_put_int(c->remote_id);
601 packet_put_cstring(service);
602 packet_put_char(wantconfirm);
603}
604void
e9a17296 605channel_register_confirm(int id, channel_callback_fn *fn)
3c0ef626 606{
607 Channel *c = channel_lookup(id);
608 if (c == NULL) {
e9a17296 609 log("channel_register_comfirm: %d: bad id", id);
3c0ef626 610 return;
611 }
e9a17296 612 c->confirm = fn;
3c0ef626 613}
614void
615channel_register_cleanup(int id, channel_callback_fn *fn)
616{
617 Channel *c = channel_lookup(id);
618 if (c == NULL) {
619 log("channel_register_cleanup: %d: bad id", id);
620 return;
621 }
622 c->detach_user = fn;
623}
624void
625channel_cancel_cleanup(int id)
626{
627 Channel *c = channel_lookup(id);
628 if (c == NULL) {
629 log("channel_cancel_cleanup: %d: bad id", id);
630 return;
631 }
632 c->detach_user = NULL;
633}
634void
635channel_register_filter(int id, channel_filter_fn *fn)
636{
637 Channel *c = channel_lookup(id);
638 if (c == NULL) {
639 log("channel_register_filter: %d: bad id", id);
640 return;
641 }
642 c->input_filter = fn;
643}
644
645void
646channel_set_fds(int id, int rfd, int wfd, int efd,
e9a17296 647 int extusage, int nonblock, u_int window_max)
3c0ef626 648{
649 Channel *c = channel_lookup(id);
650 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
651 fatal("channel_activate for non-larval channel %d.", id);
652 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
653 c->type = SSH_CHANNEL_OPEN;
e9a17296 654 c->local_window = c->local_window_max = window_max;
3c0ef626 655 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
656 packet_put_int(c->remote_id);
657 packet_put_int(c->local_window);
658 packet_send();
659}
660
661/*
662 * 'channel_pre*' are called just before select() to add any bits relevant to
663 * channels in the select bitmasks.
664 */
665/*
666 * 'channel_post*': perform any appropriate operations for channels which
667 * have events pending.
668 */
669typedef void chan_fn(Channel *c, fd_set * readset, fd_set * writeset);
670chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
671chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
672
673static void
674channel_pre_listener(Channel *c, fd_set * readset, fd_set * writeset)
675{
676 FD_SET(c->sock, readset);
677}
678
679static void
680channel_pre_connecting(Channel *c, fd_set * readset, fd_set * writeset)
681{
682 debug3("channel %d: waiting for connection", c->self);
683 FD_SET(c->sock, writeset);
684}
685
686static void
687channel_pre_open_13(Channel *c, fd_set * readset, fd_set * writeset)
688{
689 if (buffer_len(&c->input) < packet_get_maxsize())
690 FD_SET(c->sock, readset);
691 if (buffer_len(&c->output) > 0)
692 FD_SET(c->sock, writeset);
693}
694
695static void
e9a17296 696channel_pre_open(Channel *c, fd_set * readset, fd_set * writeset)
3c0ef626 697{
e9a17296 698 u_int limit = compat20 ? c->remote_window : packet_get_maxsize();
3c0ef626 699
3c0ef626 700 if (c->istate == CHAN_INPUT_OPEN &&
e9a17296 701 limit > 0 &&
702 buffer_len(&c->input) < limit)
3c0ef626 703 FD_SET(c->rfd, readset);
704 if (c->ostate == CHAN_OUTPUT_OPEN ||
705 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
706 if (buffer_len(&c->output) > 0) {
707 FD_SET(c->wfd, writeset);
708 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
700318f3 709 if (CHANNEL_EFD_OUTPUT_ACTIVE(c))
710 debug2("channel %d: obuf_empty delayed efd %d/(%d)",
711 c->self, c->efd, buffer_len(&c->extended));
712 else
713 chan_obuf_empty(c);
3c0ef626 714 }
715 }
716 /** XXX check close conditions, too */
e9a17296 717 if (compat20 && c->efd != -1) {
3c0ef626 718 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
719 buffer_len(&c->extended) > 0)
720 FD_SET(c->efd, writeset);
700318f3 721 else if (!(c->flags & CHAN_EOF_SENT) &&
722 c->extended_usage == CHAN_EXTENDED_READ &&
3c0ef626 723 buffer_len(&c->extended) < c->remote_window)
724 FD_SET(c->efd, readset);
725 }
726}
727
728static void
729channel_pre_input_draining(Channel *c, fd_set * readset, fd_set * writeset)
730{
731 if (buffer_len(&c->input) == 0) {
732 packet_start(SSH_MSG_CHANNEL_CLOSE);
733 packet_put_int(c->remote_id);
734 packet_send();
735 c->type = SSH_CHANNEL_CLOSED;
736 debug("channel %d: closing after input drain.", c->self);
737 }
738}
739
740static void
741channel_pre_output_draining(Channel *c, fd_set * readset, fd_set * writeset)
742{
743 if (buffer_len(&c->output) == 0)
744 chan_mark_dead(c);
745 else
746 FD_SET(c->sock, writeset);
747}
748
749/*
750 * This is a special state for X11 authentication spoofing. An opened X11
751 * connection (when authentication spoofing is being done) remains in this
752 * state until the first packet has been completely read. The authentication
753 * data in that packet is then substituted by the real data if it matches the
754 * fake data, and the channel is put into normal mode.
755 * XXX All this happens at the client side.
756 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
757 */
758static int
759x11_open_helper(Buffer *b)
760{
761 u_char *ucp;
762 u_int proto_len, data_len;
763
764 /* Check if the fixed size part of the packet is in buffer. */
765 if (buffer_len(b) < 12)
766 return 0;
767
768 /* Parse the lengths of variable-length fields. */
e9a17296 769 ucp = buffer_ptr(b);
3c0ef626 770 if (ucp[0] == 0x42) { /* Byte order MSB first. */
771 proto_len = 256 * ucp[6] + ucp[7];
772 data_len = 256 * ucp[8] + ucp[9];
773 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
774 proto_len = ucp[6] + 256 * ucp[7];
775 data_len = ucp[8] + 256 * ucp[9];
776 } else {
777 debug("Initial X11 packet contains bad byte order byte: 0x%x",
e9a17296 778 ucp[0]);
3c0ef626 779 return -1;
780 }
781
782 /* Check if the whole packet is in buffer. */
783 if (buffer_len(b) <
784 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
785 return 0;
786
787 /* Check if authentication protocol matches. */
788 if (proto_len != strlen(x11_saved_proto) ||
789 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
790 debug("X11 connection uses different authentication protocol.");
791 return -1;
792 }
793 /* Check if authentication data matches our fake data. */
794 if (data_len != x11_fake_data_len ||
795 memcmp(ucp + 12 + ((proto_len + 3) & ~3),
796 x11_fake_data, x11_fake_data_len) != 0) {
797 debug("X11 auth data does not match fake data.");
798 return -1;
799 }
800 /* Check fake data length */
801 if (x11_fake_data_len != x11_saved_data_len) {
802 error("X11 fake_data_len %d != saved_data_len %d",
803 x11_fake_data_len, x11_saved_data_len);
804 return -1;
805 }
806 /*
807 * Received authentication protocol and data match
808 * our fake data. Substitute the fake data with real
809 * data.
810 */
811 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
812 x11_saved_data, x11_saved_data_len);
813 return 1;
814}
815
816static void
817channel_pre_x11_open_13(Channel *c, fd_set * readset, fd_set * writeset)
818{
819 int ret = x11_open_helper(&c->output);
820 if (ret == 1) {
821 /* Start normal processing for the channel. */
822 c->type = SSH_CHANNEL_OPEN;
823 channel_pre_open_13(c, readset, writeset);
824 } else if (ret == -1) {
825 /*
826 * We have received an X11 connection that has bad
827 * authentication information.
828 */
829 log("X11 connection rejected because of wrong authentication.");
830 buffer_clear(&c->input);
831 buffer_clear(&c->output);
832 channel_close_fd(&c->sock);
833 c->sock = -1;
834 c->type = SSH_CHANNEL_CLOSED;
835 packet_start(SSH_MSG_CHANNEL_CLOSE);
836 packet_put_int(c->remote_id);
837 packet_send();
838 }
839}
840
841static void
842channel_pre_x11_open(Channel *c, fd_set * readset, fd_set * writeset)
843{
844 int ret = x11_open_helper(&c->output);
845
846 /* c->force_drain = 1; */
847
848 if (ret == 1) {
849 c->type = SSH_CHANNEL_OPEN;
e9a17296 850 channel_pre_open(c, readset, writeset);
3c0ef626 851 } else if (ret == -1) {
e9a17296 852 log("X11 connection rejected because of wrong authentication.");
3c0ef626 853 debug("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
e9a17296 854 chan_read_failed(c);
855 buffer_clear(&c->input);
856 chan_ibuf_empty(c);
857 buffer_clear(&c->output);
858 /* for proto v1, the peer will send an IEOF */
859 if (compat20)
860 chan_write_failed(c);
861 else
862 c->type = SSH_CHANNEL_OPEN;
3c0ef626 863 debug("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
864 }
865}
866
867/* try to decode a socks4 header */
868static int
869channel_decode_socks4(Channel *c, fd_set * readset, fd_set * writeset)
870{
871 u_char *p, *host;
872 int len, have, i, found;
e9a17296 873 char username[256];
3c0ef626 874 struct {
875 u_int8_t version;
876 u_int8_t command;
877 u_int16_t dest_port;
878 struct in_addr dest_addr;
879 } s4_req, s4_rsp;
880
881 debug2("channel %d: decode socks4", c->self);
882
883 have = buffer_len(&c->input);
884 len = sizeof(s4_req);
885 if (have < len)
886 return 0;
887 p = buffer_ptr(&c->input);
888 for (found = 0, i = len; i < have; i++) {
889 if (p[i] == '\0') {
890 found = 1;
891 break;
892 }
893 if (i > 1024) {
894 /* the peer is probably sending garbage */
895 debug("channel %d: decode socks4: too long",
896 c->self);
897 return -1;
898 }
899 }
900 if (!found)
901 return 0;
902 buffer_get(&c->input, (char *)&s4_req.version, 1);
903 buffer_get(&c->input, (char *)&s4_req.command, 1);
904 buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
905 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
906 have = buffer_len(&c->input);
907 p = buffer_ptr(&c->input);
908 len = strlen(p);
909 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
910 if (len > have)
911 fatal("channel %d: decode socks4: len %d > have %d",
912 c->self, len, have);
913 strlcpy(username, p, sizeof(username));
914 buffer_consume(&c->input, len);
915 buffer_consume(&c->input, 1); /* trailing '\0' */
916
917 host = inet_ntoa(s4_req.dest_addr);
918 strlcpy(c->path, host, sizeof(c->path));
919 c->host_port = ntohs(s4_req.dest_port);
e9a17296 920
3c0ef626 921 debug("channel %d: dynamic request: socks4 host %s port %u command %u",
922 c->self, host, c->host_port, s4_req.command);
923
924 if (s4_req.command != 1) {
925 debug("channel %d: cannot handle: socks4 cn %d",
926 c->self, s4_req.command);
927 return -1;
928 }
929 s4_rsp.version = 0; /* vn: 0 for reply */
930 s4_rsp.command = 90; /* cd: req granted */
931 s4_rsp.dest_port = 0; /* ignored */
932 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
933 buffer_append(&c->output, (char *)&s4_rsp, sizeof(s4_rsp));
934 return 1;
935}
936
937/* dynamic port forwarding */
938static void
939channel_pre_dynamic(Channel *c, fd_set * readset, fd_set * writeset)
940{
941 u_char *p;
942 int have, ret;
943
944 have = buffer_len(&c->input);
945 c->delayed = 0;
946 debug2("channel %d: pre_dynamic: have %d", c->self, have);
947 /* buffer_dump(&c->input); */
948 /* check if the fixed size part of the packet is in buffer. */
949 if (have < 4) {
950 /* need more */
951 FD_SET(c->sock, readset);
952 return;
953 }
954 /* try to guess the protocol */
955 p = buffer_ptr(&c->input);
956 switch (p[0]) {
957 case 0x04:
958 ret = channel_decode_socks4(c, readset, writeset);
959 break;
960 default:
961 ret = -1;
962 break;
963 }
964 if (ret < 0) {
965 chan_mark_dead(c);
966 } else if (ret == 0) {
967 debug2("channel %d: pre_dynamic: need more", c->self);
968 /* need more */
969 FD_SET(c->sock, readset);
970 } else {
971 /* switch to the next state */
972 c->type = SSH_CHANNEL_OPENING;
973 port_open_helper(c, "direct-tcpip");
974 }
975}
976
977/* This is our fake X11 server socket. */
978static void
979channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset)
980{
981 Channel *nc;
982 struct sockaddr addr;
983 int newsock;
984 socklen_t addrlen;
985 char buf[16384], *remote_ipaddr;
986 int remote_port;
987
988 if (FD_ISSET(c->sock, readset)) {
989 debug("X11 connection requested.");
990 addrlen = sizeof(addr);
991 newsock = accept(c->sock, &addr, &addrlen);
e9a17296 992 if (c->single_connection) {
993 debug("single_connection: closing X11 listener.");
994 channel_close_fd(&c->sock);
995 chan_mark_dead(c);
996 }
3c0ef626 997 if (newsock < 0) {
998 error("accept: %.100s", strerror(errno));
999 return;
1000 }
e9a17296 1001 set_nodelay(newsock);
3c0ef626 1002 remote_ipaddr = get_peer_ipaddr(newsock);
1003 remote_port = get_peer_port(newsock);
1004 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1005 remote_ipaddr, remote_port);
1006
1007 nc = channel_new("accepted x11 socket",
1008 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1009 c->local_window_max, c->local_maxpacket,
1010 0, xstrdup(buf), 1);
3c0ef626 1011 if (compat20) {
1012 packet_start(SSH2_MSG_CHANNEL_OPEN);
1013 packet_put_cstring("x11");
1014 packet_put_int(nc->self);
e9a17296 1015 packet_put_int(nc->local_window_max);
1016 packet_put_int(nc->local_maxpacket);
3c0ef626 1017 /* originator ipaddr and port */
1018 packet_put_cstring(remote_ipaddr);
1019 if (datafellows & SSH_BUG_X11FWD) {
1020 debug("ssh2 x11 bug compat mode");
1021 } else {
1022 packet_put_int(remote_port);
1023 }
1024 packet_send();
1025 } else {
1026 packet_start(SSH_SMSG_X11_OPEN);
1027 packet_put_int(nc->self);
1028 if (packet_get_protocol_flags() &
1029 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1030 packet_put_cstring(buf);
1031 packet_send();
1032 }
1033 xfree(remote_ipaddr);
1034 }
1035}
1036
1037static void
1038port_open_helper(Channel *c, char *rtype)
1039{
1040 int direct;
1041 char buf[1024];
1042 char *remote_ipaddr = get_peer_ipaddr(c->sock);
1043 u_short remote_port = get_peer_port(c->sock);
1044
1045 direct = (strcmp(rtype, "direct-tcpip") == 0);
1046
1047 snprintf(buf, sizeof buf,
1048 "%s: listening port %d for %.100s port %d, "
1049 "connect from %.200s port %d",
1050 rtype, c->listening_port, c->path, c->host_port,
1051 remote_ipaddr, remote_port);
1052
1053 xfree(c->remote_name);
1054 c->remote_name = xstrdup(buf);
1055
1056 if (compat20) {
1057 packet_start(SSH2_MSG_CHANNEL_OPEN);
1058 packet_put_cstring(rtype);
1059 packet_put_int(c->self);
1060 packet_put_int(c->local_window_max);
1061 packet_put_int(c->local_maxpacket);
1062 if (direct) {
1063 /* target host, port */
1064 packet_put_cstring(c->path);
1065 packet_put_int(c->host_port);
1066 } else {
1067 /* listen address, port */
1068 packet_put_cstring(c->path);
1069 packet_put_int(c->listening_port);
1070 }
1071 /* originator host and port */
1072 packet_put_cstring(remote_ipaddr);
1073 packet_put_int(remote_port);
1074 packet_send();
1075 } else {
1076 packet_start(SSH_MSG_PORT_OPEN);
1077 packet_put_int(c->self);
1078 packet_put_cstring(c->path);
1079 packet_put_int(c->host_port);
1080 if (packet_get_protocol_flags() &
1081 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1082 packet_put_cstring(c->remote_name);
1083 packet_send();
1084 }
1085 xfree(remote_ipaddr);
1086}
1087
1088/*
1089 * This socket is listening for connections to a forwarded TCP/IP port.
1090 */
1091static void
1092channel_post_port_listener(Channel *c, fd_set * readset, fd_set * writeset)
1093{
1094 Channel *nc;
1095 struct sockaddr addr;
1096 int newsock, nextstate;
1097 socklen_t addrlen;
1098 char *rtype;
1099
1100 if (FD_ISSET(c->sock, readset)) {
1101 debug("Connection to port %d forwarding "
1102 "to %.100s port %d requested.",
1103 c->listening_port, c->path, c->host_port);
1104
1105 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1106 nextstate = SSH_CHANNEL_OPENING;
1107 rtype = "forwarded-tcpip";
1108 } else {
1109 if (c->host_port == 0) {
1110 nextstate = SSH_CHANNEL_DYNAMIC;
1111 rtype = "dynamic-tcpip";
1112 } else {
1113 nextstate = SSH_CHANNEL_OPENING;
1114 rtype = "direct-tcpip";
1115 }
1116 }
1117
1118 addrlen = sizeof(addr);
1119 newsock = accept(c->sock, &addr, &addrlen);
1120 if (newsock < 0) {
1121 error("accept: %.100s", strerror(errno));
1122 return;
1123 }
e9a17296 1124 set_nodelay(newsock);
3c0ef626 1125 nc = channel_new(rtype,
1126 nextstate, newsock, newsock, -1,
1127 c->local_window_max, c->local_maxpacket,
1128 0, xstrdup(rtype), 1);
3c0ef626 1129 nc->listening_port = c->listening_port;
1130 nc->host_port = c->host_port;
1131 strlcpy(nc->path, c->path, sizeof(nc->path));
1132
1133 if (nextstate == SSH_CHANNEL_DYNAMIC) {
1134 /*
1135 * do not call the channel_post handler until
1136 * this flag has been reset by a pre-handler.
1137 * otherwise the FD_ISSET calls might overflow
1138 */
1139 nc->delayed = 1;
1140 } else {
1141 port_open_helper(nc, rtype);
1142 }
1143 }
1144}
1145
1146/*
1147 * This is the authentication agent socket listening for connections from
1148 * clients.
1149 */
1150static void
1151channel_post_auth_listener(Channel *c, fd_set * readset, fd_set * writeset)
1152{
1153 Channel *nc;
1154 char *name;
1155 int newsock;
1156 struct sockaddr addr;
1157 socklen_t addrlen;
1158
1159 if (FD_ISSET(c->sock, readset)) {
1160 addrlen = sizeof(addr);
1161 newsock = accept(c->sock, &addr, &addrlen);
1162 if (newsock < 0) {
1163 error("accept from auth socket: %.100s", strerror(errno));
1164 return;
1165 }
1166 name = xstrdup("accepted auth socket");
1167 nc = channel_new("accepted auth socket",
1168 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1169 c->local_window_max, c->local_maxpacket,
1170 0, name, 1);
3c0ef626 1171 if (compat20) {
1172 packet_start(SSH2_MSG_CHANNEL_OPEN);
1173 packet_put_cstring("auth-agent@openssh.com");
1174 packet_put_int(nc->self);
1175 packet_put_int(c->local_window_max);
1176 packet_put_int(c->local_maxpacket);
1177 } else {
1178 packet_start(SSH_SMSG_AGENT_OPEN);
1179 packet_put_int(nc->self);
1180 }
1181 packet_send();
1182 }
1183}
1184
1185static void
1186channel_post_connecting(Channel *c, fd_set * readset, fd_set * writeset)
1187{
1188 int err = 0;
1189 socklen_t sz = sizeof(err);
1190
1191 if (FD_ISSET(c->sock, writeset)) {
e9a17296 1192 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) {
3c0ef626 1193 err = errno;
1194 error("getsockopt SO_ERROR failed");
1195 }
1196 if (err == 0) {
1197 debug("channel %d: connected", c->self);
1198 c->type = SSH_CHANNEL_OPEN;
1199 if (compat20) {
1200 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1201 packet_put_int(c->remote_id);
1202 packet_put_int(c->self);
1203 packet_put_int(c->local_window);
1204 packet_put_int(c->local_maxpacket);
1205 } else {
1206 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1207 packet_put_int(c->remote_id);
1208 packet_put_int(c->self);
1209 }
1210 } else {
1211 debug("channel %d: not connected: %s",
1212 c->self, strerror(err));
1213 if (compat20) {
1214 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1215 packet_put_int(c->remote_id);
1216 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1217 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1218 packet_put_cstring(strerror(err));
1219 packet_put_cstring("");
1220 }
1221 } else {
1222 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1223 packet_put_int(c->remote_id);
1224 }
1225 chan_mark_dead(c);
1226 }
1227 packet_send();
1228 }
1229}
1230
1231static int
1232channel_handle_rfd(Channel *c, fd_set * readset, fd_set * writeset)
1233{
1234 char buf[16*1024];
1235 int len;
1236
1237 if (c->rfd != -1 &&
1238 FD_ISSET(c->rfd, readset)) {
1239 len = read(c->rfd, buf, sizeof(buf));
1240 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1241 return 1;
1242 if (len <= 0) {
1243 debug("channel %d: read<=0 rfd %d len %d",
1244 c->self, c->rfd, len);
1245 if (c->type != SSH_CHANNEL_OPEN) {
1246 debug("channel %d: not open", c->self);
1247 chan_mark_dead(c);
1248 return -1;
1249 } else if (compat13) {
e9a17296 1250 buffer_clear(&c->output);
3c0ef626 1251 c->type = SSH_CHANNEL_INPUT_DRAINING;
1252 debug("channel %d: input draining.", c->self);
1253 } else {
1254 chan_read_failed(c);
1255 }
1256 return -1;
1257 }
e9a17296 1258 if (c->input_filter != NULL) {
3c0ef626 1259 if (c->input_filter(c, buf, len) == -1) {
1260 debug("channel %d: filter stops", c->self);
1261 chan_read_failed(c);
1262 }
1263 } else {
1264 buffer_append(&c->input, buf, len);
1265 }
1266 }
1267 return 1;
1268}
1269static int
1270channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset)
1271{
1272 struct termios tio;
1273 u_char *data;
1274 u_int dlen;
1275 int len;
1276
1277 /* Send buffered output data to the socket. */
1278 if (c->wfd != -1 &&
1279 FD_ISSET(c->wfd, writeset) &&
1280 buffer_len(&c->output) > 0) {
1281 data = buffer_ptr(&c->output);
1282 dlen = buffer_len(&c->output);
1283 len = write(c->wfd, data, dlen);
1284 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1285 return 1;
1286 if (len <= 0) {
1287 if (c->type != SSH_CHANNEL_OPEN) {
1288 debug("channel %d: not open", c->self);
1289 chan_mark_dead(c);
1290 return -1;
1291 } else if (compat13) {
e9a17296 1292 buffer_clear(&c->output);
3c0ef626 1293 debug("channel %d: input draining.", c->self);
1294 c->type = SSH_CHANNEL_INPUT_DRAINING;
1295 } else {
1296 chan_write_failed(c);
1297 }
1298 return -1;
1299 }
1300 if (compat20 && c->isatty && dlen >= 1 && data[0] != '\r') {
1301 if (tcgetattr(c->wfd, &tio) == 0 &&
1302 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1303 /*
1304 * Simulate echo to reduce the impact of
1305 * traffic analysis. We need to match the
1306 * size of a SSH2_MSG_CHANNEL_DATA message
1307 * (4 byte channel id + data)
1308 */
1309 packet_send_ignore(4 + len);
1310 packet_send();
1311 }
1312 }
1313 buffer_consume(&c->output, len);
1314 if (compat20 && len > 0) {
1315 c->local_consumed += len;
1316 }
1317 }
1318 return 1;
1319}
1320static int
1321channel_handle_efd(Channel *c, fd_set * readset, fd_set * writeset)
1322{
1323 char buf[16*1024];
1324 int len;
1325
1326/** XXX handle drain efd, too */
1327 if (c->efd != -1) {
1328 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1329 FD_ISSET(c->efd, writeset) &&
1330 buffer_len(&c->extended) > 0) {
1331 len = write(c->efd, buffer_ptr(&c->extended),
1332 buffer_len(&c->extended));
1333 debug2("channel %d: written %d to efd %d",
1334 c->self, len, c->efd);
1335 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1336 return 1;
1337 if (len <= 0) {
1338 debug2("channel %d: closing write-efd %d",
1339 c->self, c->efd);
1340 channel_close_fd(&c->efd);
1341 } else {
1342 buffer_consume(&c->extended, len);
1343 c->local_consumed += len;
1344 }
1345 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
1346 FD_ISSET(c->efd, readset)) {
1347 len = read(c->efd, buf, sizeof(buf));
1348 debug2("channel %d: read %d from efd %d",
e9a17296 1349 c->self, len, c->efd);
3c0ef626 1350 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1351 return 1;
1352 if (len <= 0) {
1353 debug2("channel %d: closing read-efd %d",
1354 c->self, c->efd);
1355 channel_close_fd(&c->efd);
1356 } else {
1357 buffer_append(&c->extended, buf, len);
1358 }
1359 }
1360 }
1361 return 1;
1362}
1363static int
1364channel_check_window(Channel *c)
1365{
1366 if (c->type == SSH_CHANNEL_OPEN &&
1367 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1368 c->local_window < c->local_window_max/2 &&
1369 c->local_consumed > 0) {
1370 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1371 packet_put_int(c->remote_id);
1372 packet_put_int(c->local_consumed);
1373 packet_send();
1374 debug2("channel %d: window %d sent adjust %d",
1375 c->self, c->local_window,
1376 c->local_consumed);
1377 c->local_window += c->local_consumed;
1378 c->local_consumed = 0;
1379 }
1380 return 1;
1381}
1382
1383static void
e9a17296 1384channel_post_open(Channel *c, fd_set * readset, fd_set * writeset)
3c0ef626 1385{
1386 if (c->delayed)
1387 return;
1388 channel_handle_rfd(c, readset, writeset);
1389 channel_handle_wfd(c, readset, writeset);
e9a17296 1390 if (!compat20)
3c0ef626 1391 return;
3c0ef626 1392 channel_handle_efd(c, readset, writeset);
3c0ef626 1393 channel_check_window(c);
1394}
1395
1396static void
1397channel_post_output_drain_13(Channel *c, fd_set * readset, fd_set * writeset)
1398{
1399 int len;
1400 /* Send buffered output data to the socket. */
1401 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1402 len = write(c->sock, buffer_ptr(&c->output),
1403 buffer_len(&c->output));
1404 if (len <= 0)
e9a17296 1405 buffer_clear(&c->output);
3c0ef626 1406 else
1407 buffer_consume(&c->output, len);
1408 }
1409}
1410
1411static void
1412channel_handler_init_20(void)
1413{
e9a17296 1414 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
3c0ef626 1415 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1416 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1417 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
1418 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1419 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1420 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1421 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1422
e9a17296 1423 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
3c0ef626 1424 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1425 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
1426 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1427 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1428 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
e9a17296 1429 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
3c0ef626 1430}
1431
1432static void
1433channel_handler_init_13(void)
1434{
1435 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
1436 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
1437 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1438 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1439 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1440 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
1441 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1442 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1443 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1444
e9a17296 1445 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
3c0ef626 1446 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1447 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1448 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1449 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
1450 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
e9a17296 1451 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
3c0ef626 1452}
1453
1454static void
1455channel_handler_init_15(void)
1456{
e9a17296 1457 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
3c0ef626 1458 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1459 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1460 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1461 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1462 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1463 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1464
1465 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1466 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1467 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
e9a17296 1468 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
3c0ef626 1469 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
e9a17296 1470 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
3c0ef626 1471}
1472
1473static void
1474channel_handler_init(void)
1475{
1476 int i;
e9a17296 1477 for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
3c0ef626 1478 channel_pre[i] = NULL;
1479 channel_post[i] = NULL;
1480 }
1481 if (compat20)
1482 channel_handler_init_20();
1483 else if (compat13)
1484 channel_handler_init_13();
1485 else
1486 channel_handler_init_15();
1487}
1488
1489/* gc dead channels */
1490static void
1491channel_garbage_collect(Channel *c)
1492{
1493 if (c == NULL)
1494 return;
1495 if (c->detach_user != NULL) {
1496 if (!chan_is_dead(c, 0))
1497 return;
1498 debug("channel %d: gc: notify user", c->self);
1499 c->detach_user(c->self, NULL);
1500 /* if we still have a callback */
1501 if (c->detach_user != NULL)
1502 return;
1503 debug("channel %d: gc: user detached", c->self);
1504 }
1505 if (!chan_is_dead(c, 1))
1506 return;
1507 debug("channel %d: garbage collecting", c->self);
1508 channel_free(c);
1509}
1510
1511static void
1512channel_handler(chan_fn *ftab[], fd_set * readset, fd_set * writeset)
1513{
1514 static int did_init = 0;
1515 int i;
1516 Channel *c;
1517
1518 if (!did_init) {
1519 channel_handler_init();
1520 did_init = 1;
1521 }
1522 for (i = 0; i < channels_alloc; i++) {
1523 c = channels[i];
1524 if (c == NULL)
1525 continue;
1526 if (ftab[c->type] != NULL)
1527 (*ftab[c->type])(c, readset, writeset);
1528 channel_garbage_collect(c);
1529 }
1530}
1531
1532/*
1533 * Allocate/update select bitmasks and add any bits relevant to channels in
1534 * select bitmasks.
1535 */
1536void
1537channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
1538 int *nallocp, int rekeying)
1539{
1540 int n;
1541 u_int sz;
1542
1543 n = MAX(*maxfdp, channel_max_fd);
1544
1545 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask);
1546 /* perhaps check sz < nalloc/2 and shrink? */
1547 if (*readsetp == NULL || sz > *nallocp) {
1548 *readsetp = xrealloc(*readsetp, sz);
1549 *writesetp = xrealloc(*writesetp, sz);
1550 *nallocp = sz;
1551 }
1552 *maxfdp = n;
1553 memset(*readsetp, 0, sz);
1554 memset(*writesetp, 0, sz);
1555
1556 if (!rekeying)
1557 channel_handler(channel_pre, *readsetp, *writesetp);
1558}
1559
1560/*
1561 * After select, perform any appropriate operations for channels which have
1562 * events pending.
1563 */
1564void
1565channel_after_select(fd_set * readset, fd_set * writeset)
1566{
1567 channel_handler(channel_post, readset, writeset);
1568}
1569
1570
1571/* If there is data to send to the connection, enqueue some of it now. */
1572
1573void
e9a17296 1574channel_output_poll(void)
3c0ef626 1575{
1576 int len, i;
1577 Channel *c;
1578
1579 for (i = 0; i < channels_alloc; i++) {
1580 c = channels[i];
1581 if (c == NULL)
1582 continue;
1583
1584 /*
1585 * We are only interested in channels that can have buffered
1586 * incoming data.
1587 */
1588 if (compat13) {
1589 if (c->type != SSH_CHANNEL_OPEN &&
1590 c->type != SSH_CHANNEL_INPUT_DRAINING)
1591 continue;
1592 } else {
1593 if (c->type != SSH_CHANNEL_OPEN)
1594 continue;
1595 }
1596 if (compat20 &&
1597 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
1598 /* XXX is this true? */
1599 debug3("channel %d: will not send data after close", c->self);
1600 continue;
1601 }
1602
1603 /* Get the amount of buffered data for this channel. */
1604 if ((c->istate == CHAN_INPUT_OPEN ||
1605 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
1606 (len = buffer_len(&c->input)) > 0) {
1607 /*
1608 * Send some data for the other side over the secure
1609 * connection.
1610 */
1611 if (compat20) {
1612 if (len > c->remote_window)
1613 len = c->remote_window;
1614 if (len > c->remote_maxpacket)
1615 len = c->remote_maxpacket;
1616 } else {
1617 if (packet_is_interactive()) {
1618 if (len > 1024)
1619 len = 512;
1620 } else {
1621 /* Keep the packets at reasonable size. */
1622 if (len > packet_get_maxsize()/2)
1623 len = packet_get_maxsize()/2;
1624 }
1625 }
1626 if (len > 0) {
1627 packet_start(compat20 ?
1628 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
1629 packet_put_int(c->remote_id);
1630 packet_put_string(buffer_ptr(&c->input), len);
1631 packet_send();
1632 buffer_consume(&c->input, len);
1633 c->remote_window -= len;
1634 }
1635 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1636 if (compat13)
1637 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
1638 /*
1639 * input-buffer is empty and read-socket shutdown:
700318f3 1640 * tell peer, that we will not send more data: send IEOF.
1641 * hack for extended data: delay EOF if EFD still in use.
3c0ef626 1642 */
700318f3 1643 if (CHANNEL_EFD_INPUT_ACTIVE(c))
1644 debug2("channel %d: ibuf_empty delayed efd %d/(%d)",
1645 c->self, c->efd, buffer_len(&c->extended));
1646 else
1647 chan_ibuf_empty(c);
3c0ef626 1648 }
1649 /* Send extended data, i.e. stderr */
1650 if (compat20 &&
700318f3 1651 !(c->flags & CHAN_EOF_SENT) &&
3c0ef626 1652 c->remote_window > 0 &&
1653 (len = buffer_len(&c->extended)) > 0 &&
1654 c->extended_usage == CHAN_EXTENDED_READ) {
1655 debug2("channel %d: rwin %d elen %d euse %d",
1656 c->self, c->remote_window, buffer_len(&c->extended),
1657 c->extended_usage);
1658 if (len > c->remote_window)
1659 len = c->remote_window;
1660 if (len > c->remote_maxpacket)
1661 len = c->remote_maxpacket;
1662 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
1663 packet_put_int(c->remote_id);
1664 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
1665 packet_put_string(buffer_ptr(&c->extended), len);
1666 packet_send();
1667 buffer_consume(&c->extended, len);
1668 c->remote_window -= len;
1669 debug2("channel %d: sent ext data %d", c->self, len);
1670 }
1671 }
1672}
1673
1674
1675/* -- protocol input */
1676
1677void
e9a17296 1678channel_input_data(int type, u_int32_t seq, void *ctxt)
3c0ef626 1679{
1680 int id;
1681 char *data;
1682 u_int data_len;
1683 Channel *c;
1684
1685 /* Get the channel number and verify it. */
1686 id = packet_get_int();
1687 c = channel_lookup(id);
1688 if (c == NULL)
1689 packet_disconnect("Received data for nonexistent channel %d.", id);
1690
1691 /* Ignore any data for non-open channels (might happen on close) */
1692 if (c->type != SSH_CHANNEL_OPEN &&
1693 c->type != SSH_CHANNEL_X11_OPEN)
1694 return;
1695
1696 /* same for protocol 1.5 if output end is no longer open */
1697 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN)
1698 return;
1699
1700 /* Get the data. */
1701 data = packet_get_string(&data_len);
3c0ef626 1702
e9a17296 1703 if (compat20) {
3c0ef626 1704 if (data_len > c->local_maxpacket) {
1705 log("channel %d: rcvd big packet %d, maxpack %d",
1706 c->self, data_len, c->local_maxpacket);
1707 }
1708 if (data_len > c->local_window) {
1709 log("channel %d: rcvd too much data %d, win %d",
1710 c->self, data_len, c->local_window);
1711 xfree(data);
1712 return;
1713 }
1714 c->local_window -= data_len;
3c0ef626 1715 }
e9a17296 1716 packet_check_eom();
3c0ef626 1717 buffer_append(&c->output, data, data_len);
1718 xfree(data);
1719}
1720
1721void
e9a17296 1722channel_input_extended_data(int type, u_int32_t seq, void *ctxt)
3c0ef626 1723{
1724 int id;
1725 int tcode;
1726 char *data;
1727 u_int data_len;
1728 Channel *c;
1729
1730 /* Get the channel number and verify it. */
1731 id = packet_get_int();
1732 c = channel_lookup(id);
1733
1734 if (c == NULL)
1735 packet_disconnect("Received extended_data for bad channel %d.", id);
1736 if (c->type != SSH_CHANNEL_OPEN) {
1737 log("channel %d: ext data for non open", id);
1738 return;
1739 }
700318f3 1740 if (c->flags & CHAN_EOF_RCVD) {
1741 if (datafellows & SSH_BUG_EXTEOF)
1742 debug("channel %d: accepting ext data after eof", id);
1743 else
1744 packet_disconnect("Received extended_data after EOF "
1745 "on channel %d.", id);
1746 }
3c0ef626 1747 tcode = packet_get_int();
1748 if (c->efd == -1 ||
1749 c->extended_usage != CHAN_EXTENDED_WRITE ||
1750 tcode != SSH2_EXTENDED_DATA_STDERR) {
1751 log("channel %d: bad ext data", c->self);
1752 return;
1753 }
1754 data = packet_get_string(&data_len);
e9a17296 1755 packet_check_eom();
3c0ef626 1756 if (data_len > c->local_window) {
1757 log("channel %d: rcvd too much extended_data %d, win %d",
1758 c->self, data_len, c->local_window);
1759 xfree(data);
1760 return;
1761 }
1762 debug2("channel %d: rcvd ext data %d", c->self, data_len);
1763 c->local_window -= data_len;
1764 buffer_append(&c->extended, data, data_len);
1765 xfree(data);
1766}
1767
1768void
e9a17296 1769channel_input_ieof(int type, u_int32_t seq, void *ctxt)
3c0ef626 1770{
1771 int id;
1772 Channel *c;
1773
3c0ef626 1774 id = packet_get_int();
e9a17296 1775 packet_check_eom();
3c0ef626 1776 c = channel_lookup(id);
1777 if (c == NULL)
1778 packet_disconnect("Received ieof for nonexistent channel %d.", id);
1779 chan_rcvd_ieof(c);
1780
1781 /* XXX force input close */
e9a17296 1782 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) {
3c0ef626 1783 debug("channel %d: FORCE input drain", c->self);
1784 c->istate = CHAN_INPUT_WAIT_DRAIN;
e9a17296 1785 if (buffer_len(&c->input) == 0)
1786 chan_ibuf_empty(c);
3c0ef626 1787 }
1788
1789}
1790
1791void
e9a17296 1792channel_input_close(int type, u_int32_t seq, void *ctxt)
3c0ef626 1793{
1794 int id;
1795 Channel *c;
1796
3c0ef626 1797 id = packet_get_int();
e9a17296 1798 packet_check_eom();
3c0ef626 1799 c = channel_lookup(id);
1800 if (c == NULL)
1801 packet_disconnect("Received close for nonexistent channel %d.", id);
1802
1803 /*
1804 * Send a confirmation that we have closed the channel and no more
1805 * data is coming for it.
1806 */
1807 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
1808 packet_put_int(c->remote_id);
1809 packet_send();
1810
1811 /*
1812 * If the channel is in closed state, we have sent a close request,
1813 * and the other side will eventually respond with a confirmation.
1814 * Thus, we cannot free the channel here, because then there would be
1815 * no-one to receive the confirmation. The channel gets freed when
1816 * the confirmation arrives.
1817 */
1818 if (c->type != SSH_CHANNEL_CLOSED) {
1819 /*
1820 * Not a closed channel - mark it as draining, which will
1821 * cause it to be freed later.
1822 */
e9a17296 1823 buffer_clear(&c->input);
3c0ef626 1824 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
1825 }
1826}
1827
1828/* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
1829void
e9a17296 1830channel_input_oclose(int type, u_int32_t seq, void *ctxt)
3c0ef626 1831{
1832 int id = packet_get_int();
1833 Channel *c = channel_lookup(id);
e9a17296 1834
1835 packet_check_eom();
3c0ef626 1836 if (c == NULL)
1837 packet_disconnect("Received oclose for nonexistent channel %d.", id);
1838 chan_rcvd_oclose(c);
1839}
1840
1841void
e9a17296 1842channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt)
3c0ef626 1843{
1844 int id = packet_get_int();
1845 Channel *c = channel_lookup(id);
1846
e9a17296 1847 packet_check_eom();
3c0ef626 1848 if (c == NULL)
1849 packet_disconnect("Received close confirmation for "
1850 "out-of-range channel %d.", id);
1851 if (c->type != SSH_CHANNEL_CLOSED)
1852 packet_disconnect("Received close confirmation for "
1853 "non-closed channel %d (type %d).", id, c->type);
1854 channel_free(c);
1855}
1856
1857void
e9a17296 1858channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt)
3c0ef626 1859{
1860 int id, remote_id;
1861 Channel *c;
1862
3c0ef626 1863 id = packet_get_int();
1864 c = channel_lookup(id);
1865
1866 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
1867 packet_disconnect("Received open confirmation for "
1868 "non-opening channel %d.", id);
1869 remote_id = packet_get_int();
1870 /* Record the remote channel number and mark that the channel is now open. */
1871 c->remote_id = remote_id;
1872 c->type = SSH_CHANNEL_OPEN;
1873
1874 if (compat20) {
1875 c->remote_window = packet_get_int();
1876 c->remote_maxpacket = packet_get_int();
e9a17296 1877 if (c->confirm) {
3c0ef626 1878 debug2("callback start");
e9a17296 1879 c->confirm(c->self, NULL);
3c0ef626 1880 debug2("callback done");
1881 }
1882 debug("channel %d: open confirm rwindow %d rmax %d", c->self,
1883 c->remote_window, c->remote_maxpacket);
1884 }
e9a17296 1885 packet_check_eom();
3c0ef626 1886}
1887
1888static char *
1889reason2txt(int reason)
1890{
e9a17296 1891 switch (reason) {
3c0ef626 1892 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
1893 return "administratively prohibited";
1894 case SSH2_OPEN_CONNECT_FAILED:
1895 return "connect failed";
1896 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
1897 return "unknown channel type";
1898 case SSH2_OPEN_RESOURCE_SHORTAGE:
1899 return "resource shortage";
1900 }
1901 return "unknown reason";
1902}
1903
1904void
e9a17296 1905channel_input_open_failure(int type, u_int32_t seq, void *ctxt)
3c0ef626 1906{
1907 int id, reason;
1908 char *msg = NULL, *lang = NULL;
1909 Channel *c;
1910
3c0ef626 1911 id = packet_get_int();
1912 c = channel_lookup(id);
1913
1914 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
1915 packet_disconnect("Received open failure for "
1916 "non-opening channel %d.", id);
1917 if (compat20) {
1918 reason = packet_get_int();
1919 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1920 msg = packet_get_string(NULL);
1921 lang = packet_get_string(NULL);
1922 }
3c0ef626 1923 log("channel %d: open failed: %s%s%s", id,
1924 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
1925 if (msg != NULL)
1926 xfree(msg);
1927 if (lang != NULL)
1928 xfree(lang);
1929 }
e9a17296 1930 packet_check_eom();
3c0ef626 1931 /* Free the channel. This will also close the socket. */
1932 channel_free(c);
1933}
1934
1935void
e9a17296 1936channel_input_window_adjust(int type, u_int32_t seq, void *ctxt)
3c0ef626 1937{
1938 Channel *c;
1939 int id, adjust;
1940
1941 if (!compat20)
1942 return;
1943
1944 /* Get the channel number and verify it. */
1945 id = packet_get_int();
1946 c = channel_lookup(id);
1947
1948 if (c == NULL || c->type != SSH_CHANNEL_OPEN) {
1949 log("Received window adjust for "
1950 "non-open channel %d.", id);
1951 return;
1952 }
1953 adjust = packet_get_int();
e9a17296 1954 packet_check_eom();
3c0ef626 1955 debug2("channel %d: rcvd adjust %d", id, adjust);
1956 c->remote_window += adjust;
1957}
1958
1959void
e9a17296 1960channel_input_port_open(int type, u_int32_t seq, void *ctxt)
3c0ef626 1961{
1962 Channel *c = NULL;
1963 u_short host_port;
1964 char *host, *originator_string;
1965 int remote_id, sock = -1;
1966
1967 remote_id = packet_get_int();
1968 host = packet_get_string(NULL);
1969 host_port = packet_get_int();
1970
1971 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
1972 originator_string = packet_get_string(NULL);
1973 } else {
1974 originator_string = xstrdup("unknown (remote did not supply name)");
1975 }
e9a17296 1976 packet_check_eom();
3c0ef626 1977 sock = channel_connect_to(host, host_port);
1978 if (sock != -1) {
1979 c = channel_new("connected socket",
1980 SSH_CHANNEL_CONNECTING, sock, sock, -1, 0, 0, 0,
1981 originator_string, 1);
e9a17296 1982 c->remote_id = remote_id;
3c0ef626 1983 }
1984 if (c == NULL) {
1985 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1986 packet_put_int(remote_id);
1987 packet_send();
1988 }
1989 xfree(host);
1990}
1991
1992
1993/* -- tcp forwarding */
1994
1995void
1996channel_set_af(int af)
1997{
1998 IPv4or6 = af;
1999}
2000
e9a17296 2001static int
2002channel_setup_fwd_listener(int type, const char *listen_addr, u_short listen_port,
2003 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
3c0ef626 2004{
2005 Channel *c;
e9a17296 2006 int success, sock, on = 1;
3c0ef626 2007 struct addrinfo hints, *ai, *aitop;
3c0ef626 2008 const char *host;
e9a17296 2009 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
3c0ef626 2010 struct linger linger;
2011
2012 success = 0;
e9a17296 2013 host = (type == SSH_CHANNEL_RPORT_LISTENER) ?
2014 listen_addr : host_to_connect;
3c0ef626 2015
e9a17296 2016 if (host == NULL) {
2017 error("No forward host name.");
2018 return success;
3c0ef626 2019 }
3c0ef626 2020 if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) {
2021 error("Forward host name too long.");
2022 return success;
2023 }
2024
3c0ef626 2025 /*
2026 * getaddrinfo returns a loopback address if the hostname is
2027 * set to NULL and hints.ai_flags is not AI_PASSIVE
2028 */
2029 memset(&hints, 0, sizeof(hints));
2030 hints.ai_family = IPv4or6;
2031 hints.ai_flags = gateway_ports ? AI_PASSIVE : 0;
2032 hints.ai_socktype = SOCK_STREAM;
2033 snprintf(strport, sizeof strport, "%d", listen_port);
2034 if (getaddrinfo(NULL, strport, &hints, &aitop) != 0)
2035 packet_disconnect("getaddrinfo: fatal error");
2036
2037 for (ai = aitop; ai; ai = ai->ai_next) {
2038 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2039 continue;
2040 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2041 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
e9a17296 2042 error("channel_setup_fwd_listener: getnameinfo failed");
3c0ef626 2043 continue;
2044 }
2045 /* Create a port to listen for the host. */
2046 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2047 if (sock < 0) {
2048 /* this is no error since kernel may not support ipv6 */
2049 verbose("socket: %.100s", strerror(errno));
2050 continue;
2051 }
2052 /*
2053 * Set socket options. We would like the socket to disappear
2054 * as soon as it has been closed for whatever reason.
2055 */
e9a17296 2056 setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));
3c0ef626 2057 linger.l_onoff = 1;
2058 linger.l_linger = 5;
e9a17296 2059 setsockopt(sock, SOL_SOCKET, SO_LINGER, &linger, sizeof(linger));
3c0ef626 2060 debug("Local forwarding listening on %s port %s.", ntop, strport);
2061
2062 /* Bind the socket to the address. */
2063 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2064 /* address can be in use ipv6 address is already bound */
2065 if (!ai->ai_next)
2066 error("bind: %.100s", strerror(errno));
2067 else
2068 verbose("bind: %.100s", strerror(errno));
2069
2070 close(sock);
2071 continue;
2072 }
2073 /* Start listening for connections on the socket. */
2074 if (listen(sock, 5) < 0) {
2075 error("listen: %.100s", strerror(errno));
2076 close(sock);
2077 continue;
2078 }
2079 /* Allocate a channel number for the socket. */
2080 c = channel_new("port listener", type, sock, sock, -1,
2081 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2082 0, xstrdup("port listener"), 1);
3c0ef626 2083 strlcpy(c->path, host, sizeof(c->path));
2084 c->host_port = port_to_connect;
2085 c->listening_port = listen_port;
2086 success = 1;
2087 }
2088 if (success == 0)
e9a17296 2089 error("channel_setup_fwd_listener: cannot listen to port: %d",
3c0ef626 2090 listen_port);
2091 freeaddrinfo(aitop);
2092 return success;
2093}
2094
e9a17296 2095/* protocol local port fwd, used by ssh (and sshd in v1) */
2096int
2097channel_setup_local_fwd_listener(u_short listen_port,
2098 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2099{
2100 return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER,
2101 NULL, listen_port, host_to_connect, port_to_connect, gateway_ports);
2102}
2103
2104/* protocol v2 remote port fwd, used by sshd */
2105int
2106channel_setup_remote_fwd_listener(const char *listen_address,
2107 u_short listen_port, int gateway_ports)
2108{
2109 return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER,
2110 listen_address, listen_port, NULL, 0, gateway_ports);
2111}
2112
3c0ef626 2113/*
2114 * Initiate forwarding of connections to port "port" on remote host through
2115 * the secure channel to host:port from local side.
2116 */
2117
2118void
2119channel_request_remote_forwarding(u_short listen_port,
2120 const char *host_to_connect, u_short port_to_connect)
2121{
e9a17296 2122 int type, success = 0;
3c0ef626 2123
2124 /* Record locally that connection to this host/port is permitted. */
2125 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2126 fatal("channel_request_remote_forwarding: too many forwards");
2127
2128 /* Send the forward request to the remote side. */
2129 if (compat20) {
2130 const char *address_to_bind = "0.0.0.0";
2131 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2132 packet_put_cstring("tcpip-forward");
700318f3 2133 packet_put_char(1); /* boolean: want reply */
3c0ef626 2134 packet_put_cstring(address_to_bind);
2135 packet_put_int(listen_port);
2136 packet_send();
2137 packet_write_wait();
2138 /* Assume that server accepts the request */
2139 success = 1;
2140 } else {
2141 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2142 packet_put_int(listen_port);
2143 packet_put_cstring(host_to_connect);
2144 packet_put_int(port_to_connect);
2145 packet_send();
2146 packet_write_wait();
2147
2148 /* Wait for response from the remote side. */
e9a17296 2149 type = packet_read();
3c0ef626 2150 switch (type) {
2151 case SSH_SMSG_SUCCESS:
2152 success = 1;
2153 break;
2154 case SSH_SMSG_FAILURE:
2155 log("Warning: Server denied remote port forwarding.");
2156 break;
2157 default:
2158 /* Unknown packet */
2159 packet_disconnect("Protocol error for port forward request:"
2160 "received packet type %d.", type);
2161 }
2162 }
2163 if (success) {
2164 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2165 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2166 permitted_opens[num_permitted_opens].listen_port = listen_port;
2167 num_permitted_opens++;
2168 }
2169}
2170
2171/*
2172 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
2173 * listening for the port, and sends back a success reply (or disconnect
2174 * message if there was an error). This never returns if there was an error.
2175 */
2176
2177void
2178channel_input_port_forward_request(int is_root, int gateway_ports)
2179{
2180 u_short port, host_port;
2181 char *hostname;
2182
2183 /* Get arguments from the packet. */
2184 port = packet_get_int();
2185 hostname = packet_get_string(NULL);
2186 host_port = packet_get_int();
2187
2188#ifndef HAVE_CYGWIN
2189 /*
2190 * Check that an unprivileged user is not trying to forward a
2191 * privileged port.
2192 */
2193 if (port < IPPORT_RESERVED && !is_root)
2194 packet_disconnect("Requested forwarding of port %d but user is not root.",
2195 port);
2196#endif
2197 /* Initiate forwarding */
e9a17296 2198 channel_setup_local_fwd_listener(port, hostname, host_port, gateway_ports);
3c0ef626 2199
2200 /* Free the argument string. */
2201 xfree(hostname);
2202}
2203
2204/*
2205 * Permits opening to any host/port if permitted_opens[] is empty. This is
2206 * usually called by the server, because the user could connect to any port
2207 * anyway, and the server has no way to know but to trust the client anyway.
2208 */
2209void
e9a17296 2210channel_permit_all_opens(void)
3c0ef626 2211{
2212 if (num_permitted_opens == 0)
2213 all_opens_permitted = 1;
2214}
2215
2216void
2217channel_add_permitted_opens(char *host, int port)
2218{
2219 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2220 fatal("channel_request_remote_forwarding: too many forwards");
2221 debug("allow port forwarding to host %s port %d", host, port);
2222
2223 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
2224 permitted_opens[num_permitted_opens].port_to_connect = port;
2225 num_permitted_opens++;
2226
2227 all_opens_permitted = 0;
2228}
2229
2230void
2231channel_clear_permitted_opens(void)
2232{
2233 int i;
2234
2235 for (i = 0; i < num_permitted_opens; i++)
2236 xfree(permitted_opens[i].host_to_connect);
2237 num_permitted_opens = 0;
2238
2239}
2240
2241
2242/* return socket to remote host, port */
2243static int
2244connect_to(const char *host, u_short port)
2245{
2246 struct addrinfo hints, *ai, *aitop;
2247 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2248 int gaierr;
2249 int sock = -1;
2250
2251 memset(&hints, 0, sizeof(hints));
2252 hints.ai_family = IPv4or6;
2253 hints.ai_socktype = SOCK_STREAM;
2254 snprintf(strport, sizeof strport, "%d", port);
2255 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
2256 error("connect_to %.100s: unknown host (%s)", host,
2257 gai_strerror(gaierr));
2258 return -1;
2259 }
2260 for (ai = aitop; ai; ai = ai->ai_next) {
2261 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2262 continue;
2263 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2264 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2265 error("connect_to: getnameinfo failed");
2266 continue;
2267 }
2268 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2269 if (sock < 0) {
2270 error("socket: %.100s", strerror(errno));
2271 continue;
2272 }
2273 if (fcntl(sock, F_SETFL, O_NONBLOCK) < 0)
2274 fatal("connect_to: F_SETFL: %s", strerror(errno));
2275 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 &&
2276 errno != EINPROGRESS) {
2277 error("connect_to %.100s port %s: %.100s", ntop, strport,
2278 strerror(errno));
2279 close(sock);
2280 continue; /* fail -- try next */
2281 }
2282 break; /* success */
2283
2284 }
2285 freeaddrinfo(aitop);
2286 if (!ai) {
2287 error("connect_to %.100s port %d: failed.", host, port);
2288 return -1;
2289 }
2290 /* success */
e9a17296 2291 set_nodelay(sock);
3c0ef626 2292 return sock;
2293}
2294
2295int
2296channel_connect_by_listen_address(u_short listen_port)
2297{
2298 int i;
2299
2300 for (i = 0; i < num_permitted_opens; i++)
2301 if (permitted_opens[i].listen_port == listen_port)
2302 return connect_to(
2303 permitted_opens[i].host_to_connect,
2304 permitted_opens[i].port_to_connect);
2305 error("WARNING: Server requests forwarding for unknown listen_port %d",
2306 listen_port);
2307 return -1;
2308}
2309
2310/* Check if connecting to that port is permitted and connect. */
2311int
2312channel_connect_to(const char *host, u_short port)
2313{
2314 int i, permit;
2315
2316 permit = all_opens_permitted;
2317 if (!permit) {
2318 for (i = 0; i < num_permitted_opens; i++)
2319 if (permitted_opens[i].port_to_connect == port &&
2320 strcmp(permitted_opens[i].host_to_connect, host) == 0)
2321 permit = 1;
2322
2323 }
2324 if (!permit) {
2325 log("Received request to connect to host %.100s port %d, "
2326 "but the request was denied.", host, port);
2327 return -1;
2328 }
2329 return connect_to(host, port);
2330}
2331
2332/* -- X11 forwarding */
2333
2334/*
2335 * Creates an internet domain socket for listening for X11 connections.
e9a17296 2336 * Returns a suitable display number for the DISPLAY variable, or -1 if
2337 * an error occurs.
3c0ef626 2338 */
e9a17296 2339int
2340x11_create_display_inet(int x11_display_offset, int x11_use_localhost,
2341 int single_connection)
3c0ef626 2342{
e9a17296 2343 Channel *nc = NULL;
3c0ef626 2344 int display_number, sock;
2345 u_short port;
2346 struct addrinfo hints, *ai, *aitop;
2347 char strport[NI_MAXSERV];
2348 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
3c0ef626 2349
2350 for (display_number = x11_display_offset;
e9a17296 2351 display_number < MAX_DISPLAYS;
2352 display_number++) {
3c0ef626 2353 port = 6000 + display_number;
2354 memset(&hints, 0, sizeof(hints));
2355 hints.ai_family = IPv4or6;
e9a17296 2356 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE;
3c0ef626 2357 hints.ai_socktype = SOCK_STREAM;
2358 snprintf(strport, sizeof strport, "%d", port);
2359 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
2360 error("getaddrinfo: %.100s", gai_strerror(gaierr));
e9a17296 2361 return -1;
3c0ef626 2362 }
2363 for (ai = aitop; ai; ai = ai->ai_next) {
2364 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2365 continue;
2366 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2367 if (sock < 0) {
2368 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
2369 error("socket: %.100s", strerror(errno));
e9a17296 2370 return -1;
3c0ef626 2371 } else {
2372 debug("x11_create_display_inet: Socket family %d not supported",
2373 ai->ai_family);
2374 continue;
2375 }
2376 }
2377 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2378 debug("bind port %d: %.100s", port, strerror(errno));
3c0ef626 2379 close(sock);
2380
2381 if (ai->ai_next)
2382 continue;
2383
2384 for (n = 0; n < num_socks; n++) {
3c0ef626 2385 close(socks[n]);
2386 }
2387 num_socks = 0;
2388 break;
2389 }
2390 socks[num_socks++] = sock;
2391#ifndef DONT_TRY_OTHER_AF
2392 if (num_socks == NUM_SOCKS)
2393 break;
2394#else
2395 break;
2396#endif
2397 }
2398 freeaddrinfo(aitop);
2399 if (num_socks > 0)
2400 break;
2401 }
2402 if (display_number >= MAX_DISPLAYS) {
2403 error("Failed to allocate internet-domain X11 display socket.");
e9a17296 2404 return -1;
3c0ef626 2405 }
2406 /* Start listening for connections on the socket. */
2407 for (n = 0; n < num_socks; n++) {
2408 sock = socks[n];
2409 if (listen(sock, 5) < 0) {
2410 error("listen: %.100s", strerror(errno));
3c0ef626 2411 close(sock);
e9a17296 2412 return -1;
3c0ef626 2413 }
3c0ef626 2414 }
3c0ef626 2415
2416 /* Allocate a channel for each socket. */
2417 for (n = 0; n < num_socks; n++) {
2418 sock = socks[n];
e9a17296 2419 nc = channel_new("x11 listener",
3c0ef626 2420 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
2421 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2422 0, xstrdup("X11 inet listener"), 1);
e9a17296 2423 nc->single_connection = single_connection;
3c0ef626 2424 }
2425
e9a17296 2426 /* Return the display number for the DISPLAY environment variable. */
2427 return display_number;
3c0ef626 2428}
2429
3c0ef626 2430static int
2431connect_local_xsocket(u_int dnr)
2432{
3c0ef626 2433 int sock;
2434 struct sockaddr_un addr;
3c0ef626 2435
e9a17296 2436 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2437 if (sock < 0)
2438 error("socket: %.100s", strerror(errno));
2439 memset(&addr, 0, sizeof(addr));
2440 addr.sun_family = AF_UNIX;
2441 snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr);
2442 if (connect(sock, (struct sockaddr *) & addr, sizeof(addr)) == 0)
2443 return sock;
2444 close(sock);
3c0ef626 2445 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
2446 return -1;
2447}
2448
2449int
2450x11_connect_display(void)
2451{
2452 int display_number, sock = 0;
2453 const char *display;
2454 char buf[1024], *cp;
2455 struct addrinfo hints, *ai, *aitop;
2456 char strport[NI_MAXSERV];
2457 int gaierr;
2458
2459 /* Try to open a socket for the local X server. */
2460 display = getenv("DISPLAY");
2461 if (!display) {
2462 error("DISPLAY not set.");
2463 return -1;
2464 }
2465 /*
2466 * Now we decode the value of the DISPLAY variable and make a
2467 * connection to the real X server.
2468 */
2469
2470 /*
2471 * Check if it is a unix domain socket. Unix domain displays are in
2472 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
2473 */
2474 if (strncmp(display, "unix:", 5) == 0 ||
2475 display[0] == ':') {
2476 /* Connect to the unix domain socket. */
2477 if (sscanf(strrchr(display, ':') + 1, "%d", &display_number) != 1) {
2478 error("Could not parse display number from DISPLAY: %.100s",
e9a17296 2479 display);
3c0ef626 2480 return -1;
2481 }
2482 /* Create a socket. */
2483 sock = connect_local_xsocket(display_number);
2484 if (sock < 0)
2485 return -1;
2486
2487 /* OK, we now have a connection to the display. */
2488 return sock;
2489 }
2490 /*
2491 * Connect to an inet socket. The DISPLAY value is supposedly
2492 * hostname:d[.s], where hostname may also be numeric IP address.
2493 */
e9a17296 2494 strlcpy(buf, display, sizeof(buf));
3c0ef626 2495 cp = strchr(buf, ':');
2496 if (!cp) {
2497 error("Could not find ':' in DISPLAY: %.100s", display);
2498 return -1;
2499 }
2500 *cp = 0;
2501 /* buf now contains the host name. But first we parse the display number. */
2502 if (sscanf(cp + 1, "%d", &display_number) != 1) {
2503 error("Could not parse display number from DISPLAY: %.100s",
e9a17296 2504 display);
3c0ef626 2505 return -1;
2506 }
2507
2508 /* Look up the host address */
2509 memset(&hints, 0, sizeof(hints));
2510 hints.ai_family = IPv4or6;
2511 hints.ai_socktype = SOCK_STREAM;
2512 snprintf(strport, sizeof strport, "%d", 6000 + display_number);
2513 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
2514 error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr));
2515 return -1;
2516 }
2517 for (ai = aitop; ai; ai = ai->ai_next) {
2518 /* Create a socket. */
2519 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2520 if (sock < 0) {
2521 debug("socket: %.100s", strerror(errno));
2522 continue;
2523 }
2524 /* Connect it to the display. */
2525 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2526 debug("connect %.100s port %d: %.100s", buf,
2527 6000 + display_number, strerror(errno));
2528 close(sock);
2529 continue;
2530 }
2531 /* Success */
2532 break;
2533 }
2534 freeaddrinfo(aitop);
2535 if (!ai) {
2536 error("connect %.100s port %d: %.100s", buf, 6000 + display_number,
2537 strerror(errno));
2538 return -1;
2539 }
e9a17296 2540 set_nodelay(sock);
3c0ef626 2541 return sock;
2542}
2543
2544/*
2545 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
2546 * the remote channel number. We should do whatever we want, and respond
2547 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
2548 */
2549
2550void
e9a17296 2551x11_input_open(int type, u_int32_t seq, void *ctxt)
3c0ef626 2552{
2553 Channel *c = NULL;
2554 int remote_id, sock = 0;
2555 char *remote_host;
2556
2557 debug("Received X11 open request.");
2558
2559 remote_id = packet_get_int();
2560
2561 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2562 remote_host = packet_get_string(NULL);
2563 } else {
2564 remote_host = xstrdup("unknown (remote did not supply name)");
2565 }
e9a17296 2566 packet_check_eom();
3c0ef626 2567
2568 /* Obtain a connection to the real X display. */
2569 sock = x11_connect_display();
2570 if (sock != -1) {
2571 /* Allocate a channel for this connection. */
2572 c = channel_new("connected x11 socket",
2573 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
2574 remote_host, 1);
e9a17296 2575 c->remote_id = remote_id;
2576 c->force_drain = 1;
3c0ef626 2577 }
2578 if (c == NULL) {
2579 /* Send refusal to the remote host. */
2580 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2581 packet_put_int(remote_id);
2582 } else {
2583 /* Send a confirmation to the remote host. */
2584 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2585 packet_put_int(remote_id);
2586 packet_put_int(c->self);
2587 }
2588 packet_send();
2589}
2590
2591/* dummy protocol handler that denies SSH-1 requests (agent/x11) */
2592void
e9a17296 2593deny_input_open(int type, u_int32_t seq, void *ctxt)
3c0ef626 2594{
2595 int rchan = packet_get_int();
e9a17296 2596 switch (type) {
3c0ef626 2597 case SSH_SMSG_AGENT_OPEN:
2598 error("Warning: ssh server tried agent forwarding.");
2599 break;
2600 case SSH_SMSG_X11_OPEN:
2601 error("Warning: ssh server tried X11 forwarding.");
2602 break;
2603 default:
e9a17296 2604 error("deny_input_open: type %d", type);
3c0ef626 2605 break;
2606 }
2607 error("Warning: this is probably a break in attempt by a malicious server.");
2608 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2609 packet_put_int(rchan);
2610 packet_send();
2611}
2612
2613/*
2614 * Requests forwarding of X11 connections, generates fake authentication
2615 * data, and enables authentication spoofing.
2616 * This should be called in the client only.
2617 */
2618void
2619x11_request_forwarding_with_spoofing(int client_session_id,
2620 const char *proto, const char *data)
2621{
2622 u_int data_len = (u_int) strlen(data) / 2;
2623 u_int i, value, len;
2624 char *new_data;
2625 int screen_number;
2626 const char *cp;
2627 u_int32_t rand = 0;
2628
2629 cp = getenv("DISPLAY");
2630 if (cp)
2631 cp = strchr(cp, ':');
2632 if (cp)
2633 cp = strchr(cp, '.');
2634 if (cp)
2635 screen_number = atoi(cp + 1);
2636 else
2637 screen_number = 0;
2638
2639 /* Save protocol name. */
2640 x11_saved_proto = xstrdup(proto);
2641
2642 /*
2643 * Extract real authentication data and generate fake data of the
2644 * same length.
2645 */
2646 x11_saved_data = xmalloc(data_len);
2647 x11_fake_data = xmalloc(data_len);
2648 for (i = 0; i < data_len; i++) {
2649 if (sscanf(data + 2 * i, "%2x", &value) != 1)
2650 fatal("x11_request_forwarding: bad authentication data: %.100s", data);
2651 if (i % 4 == 0)
2652 rand = arc4random();
2653 x11_saved_data[i] = value;
2654 x11_fake_data[i] = rand & 0xff;
2655 rand >>= 8;
2656 }
2657 x11_saved_data_len = data_len;
2658 x11_fake_data_len = data_len;
2659
2660 /* Convert the fake data into hex. */
2661 len = 2 * data_len + 1;
2662 new_data = xmalloc(len);
2663 for (i = 0; i < data_len; i++)
2664 snprintf(new_data + 2 * i, len - 2 * i,
2665 "%02x", (u_char) x11_fake_data[i]);
2666
2667 /* Send the request packet. */
2668 if (compat20) {
2669 channel_request_start(client_session_id, "x11-req", 0);
2670 packet_put_char(0); /* XXX bool single connection */
2671 } else {
2672 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
2673 }
2674 packet_put_cstring(proto);
2675 packet_put_cstring(new_data);
2676 packet_put_int(screen_number);
2677 packet_send();
2678 packet_write_wait();
2679 xfree(new_data);
2680}
2681
2682
2683/* -- agent forwarding */
2684
2685/* Sends a message to the server to request authentication fd forwarding. */
2686
2687void
e9a17296 2688auth_request_forwarding(void)
3c0ef626 2689{
2690 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
2691 packet_send();
2692 packet_write_wait();
2693}
2694
2695/*
2696 * Returns the name of the forwarded authentication socket. Returns NULL if
2697 * there is no forwarded authentication socket. The returned value points to
2698 * a static buffer.
2699 */
2700
2701char *
e9a17296 2702auth_get_socket_name(void)
3c0ef626 2703{
2704 return auth_sock_name;
2705}
2706
2707/* removes the agent forwarding socket */
2708
2709void
2710auth_sock_cleanup_proc(void *_pw)
2711{
2712 struct passwd *pw = _pw;
2713
2714 if (auth_sock_name) {
2715 temporarily_use_uid(pw);
2716 unlink(auth_sock_name);
2717 rmdir(auth_sock_dir);
2718 auth_sock_name = NULL;
2719 restore_uid();
2720 }
2721}
2722
2723/*
2724 * This is called to process SSH_CMSG_AGENT_REQUEST_FORWARDING on the server.
2725 * This starts forwarding authentication requests.
2726 */
2727
2728int
2729auth_input_request_forwarding(struct passwd * pw)
2730{
2731 Channel *nc;
2732 int sock;
2733 struct sockaddr_un sunaddr;
2734
2735 if (auth_get_socket_name() != NULL) {
2736 error("authentication forwarding requested twice.");
2737 return 0;
2738 }
2739
2740 /* Temporarily drop privileged uid for mkdir/bind. */
2741 temporarily_use_uid(pw);
2742
2743 /* Allocate a buffer for the socket name, and format the name. */
2744 auth_sock_name = xmalloc(MAXPATHLEN);
2745 auth_sock_dir = xmalloc(MAXPATHLEN);
2746 strlcpy(auth_sock_dir, "/tmp/ssh-XXXXXXXX", MAXPATHLEN);
2747
2748 /* Create private directory for socket */
2749 if (mkdtemp(auth_sock_dir) == NULL) {
2750 packet_send_debug("Agent forwarding disabled: "
2751 "mkdtemp() failed: %.100s", strerror(errno));
2752 restore_uid();
2753 xfree(auth_sock_name);
2754 xfree(auth_sock_dir);
2755 auth_sock_name = NULL;
2756 auth_sock_dir = NULL;
2757 return 0;
2758 }
2759 snprintf(auth_sock_name, MAXPATHLEN, "%s/agent.%d",
2760 auth_sock_dir, (int) getpid());
2761
2762 /* delete agent socket on fatal() */
2763 fatal_add_cleanup(auth_sock_cleanup_proc, pw);
2764
2765 /* Create the socket. */
2766 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2767 if (sock < 0)
2768 packet_disconnect("socket: %.100s", strerror(errno));
2769
2770 /* Bind it to the name. */
2771 memset(&sunaddr, 0, sizeof(sunaddr));
2772 sunaddr.sun_family = AF_UNIX;
e9a17296 2773 strlcpy(sunaddr.sun_path, auth_sock_name, sizeof(sunaddr.sun_path));
3c0ef626 2774
2775 if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0)
2776 packet_disconnect("bind: %.100s", strerror(errno));
2777
2778 /* Restore the privileged uid. */
2779 restore_uid();
2780
2781 /* Start listening on the socket. */
2782 if (listen(sock, 5) < 0)
2783 packet_disconnect("listen: %.100s", strerror(errno));
2784
2785 /* Allocate a channel for the authentication agent socket. */
2786 nc = channel_new("auth socket",
2787 SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1,
2788 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2789 0, xstrdup("auth socket"), 1);
3c0ef626 2790 strlcpy(nc->path, auth_sock_name, sizeof(nc->path));
2791 return 1;
2792}
2793
2794/* This is called to process an SSH_SMSG_AGENT_OPEN message. */
2795
2796void
e9a17296 2797auth_input_open_request(int type, u_int32_t seq, void *ctxt)
3c0ef626 2798{
2799 Channel *c = NULL;
2800 int remote_id, sock;
2801 char *name;
2802
3c0ef626 2803 /* Read the remote channel number from the message. */
2804 remote_id = packet_get_int();
e9a17296 2805 packet_check_eom();
3c0ef626 2806
2807 /*
2808 * Get a connection to the local authentication agent (this may again
2809 * get forwarded).
2810 */
2811 sock = ssh_get_authentication_socket();
2812
2813 /*
2814 * If we could not connect the agent, send an error message back to
2815 * the server. This should never happen unless the agent dies,
2816 * because authentication forwarding is only enabled if we have an
2817 * agent.
2818 */
2819 if (sock >= 0) {
2820 name = xstrdup("authentication agent connection");
2821 c = channel_new("", SSH_CHANNEL_OPEN, sock, sock,
2822 -1, 0, 0, 0, name, 1);
e9a17296 2823 c->remote_id = remote_id;
2824 c->force_drain = 1;
3c0ef626 2825 }
2826 if (c == NULL) {
2827 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2828 packet_put_int(remote_id);
2829 } else {
2830 /* Send a confirmation to the remote host. */
2831 debug("Forwarding authentication connection.");
2832 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2833 packet_put_int(remote_id);
2834 packet_put_int(c->self);
2835 }
2836 packet_send();
2837}
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