1 /* $OpenBSD: channels.c,v 1.438 2024/05/17 00:30:23 djm Exp $ */
2 /*
3 * Author: Tatu Ylonen <ylo@cs.hut.fi>
4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5 * All rights reserved
6 * This file contains functions for generic socket connection forwarding.
7 * There is also code for initiating connection forwarding for X11 connections,
8 * arbitrary tcp/ip connections, and the authentication agent connection.
9 *
10 * As far as I am concerned, the code I have written for this software
11 * can be used freely for any purpose. Any derived versions of this
12 * software must be clearly marked as such, and if the derived work is
13 * incompatible with the protocol description in the RFC file, it must be
14 * called by a name other than "ssh" or "Secure Shell".
15 *
16 * SSH2 support added by Markus Friedl.
17 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved.
18 * Copyright (c) 1999 Dug Song. All rights reserved.
19 * Copyright (c) 1999 Theo de Raadt. All rights reserved.
20 *
21 * Redistribution and use in source and binary forms, with or without
22 * modification, are permitted provided that the following conditions
23 * are met:
24 * 1. Redistributions of source code must retain the above copyright
25 * notice, this list of conditions and the following disclaimer.
26 * 2. Redistributions in binary form must reproduce the above copyright
27 * notice, this list of conditions and the following disclaimer in the
28 * documentation and/or other materials provided with the distribution.
29 *
30 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
31 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
32 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
33 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
34 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
35 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
36 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
37 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
38 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
39 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
40 */
41
42 #include "includes.h"
43
44 #include <sys/types.h>
45 #include <sys/stat.h>
46 #include <sys/ioctl.h>
47 #include <sys/un.h>
48 #include <sys/socket.h>
49 #ifdef HAVE_SYS_TIME_H
50 # include <sys/time.h>
51 #endif
52
53 #include <netinet/in.h>
54 #include <arpa/inet.h>
55
56 #include <errno.h>
57 #include <fcntl.h>
58 #include <limits.h>
59 #include <netdb.h>
60 #ifdef HAVE_POLL_H
61 #include <poll.h>
62 #endif
63 #include <stdarg.h>
64 #ifdef HAVE_STDINT_H
65 # include <stdint.h>
66 #endif
67 #include <stdio.h>
68 #include <stdlib.h>
69 #include <string.h>
70 #include <termios.h>
71 #include <unistd.h>
72
73 #include "openbsd-compat/sys-queue.h"
74 #include "xmalloc.h"
75 #include "ssh.h"
76 #include "ssh2.h"
77 #include "ssherr.h"
78 #include "sshbuf.h"
79 #include "packet.h"
80 #include "log.h"
81 #include "misc.h"
82 #include "channels.h"
83 #include "compat.h"
84 #include "canohost.h"
85 #include "sshkey.h"
86 #include "authfd.h"
87 #include "pathnames.h"
88 #include "match.h"
89
90 /* XXX remove once we're satisfied there's no lurking bugs */
91 /* #define DEBUG_CHANNEL_POLL 1 */
92
93 /* -- agent forwarding */
94 #define NUM_SOCKS 10
95
96 /* -- X11 forwarding */
97 /* Maximum number of fake X11 displays to try. */
98 #define MAX_DISPLAYS 1000
99
100 /* Per-channel callback for pre/post IO actions */
101 typedef void chan_fn(struct ssh *, Channel *c);
102
103 /*
104 * Data structure for storing which hosts are permitted for forward requests.
105 * The local sides of any remote forwards are stored in this array to prevent
106 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local
107 * network (which might be behind a firewall).
108 */
109 /* XXX: streamlocal wants a path instead of host:port */
110 /* Overload host_to_connect; we could just make this match Forward */
111 /* XXX - can we use listen_host instead of listen_path? */
112 struct permission {
113 char *host_to_connect; /* Connect to 'host'. */
114 int port_to_connect; /* Connect to 'port'. */
115 char *listen_host; /* Remote side should listen address. */
116 char *listen_path; /* Remote side should listen path. */
117 int listen_port; /* Remote side should listen port. */
118 Channel *downstream; /* Downstream mux*/
119 };
120
121 /*
122 * Stores the forwarding permission state for a single direction (local or
123 * remote).
124 */
125 struct permission_set {
126 /*
127 * List of all local permitted host/port pairs to allow for the
128 * user.
129 */
130 u_int num_permitted_user;
131 struct permission *permitted_user;
132
133 /*
134 * List of all permitted host/port pairs to allow for the admin.
135 */
136 u_int num_permitted_admin;
137 struct permission *permitted_admin;
138
139 /*
140 * If this is true, all opens/listens are permitted. This is the
141 * case on the server on which we have to trust the client anyway,
142 * and the user could do anything after logging in.
143 */
144 int all_permitted;
145 };
146
147 /* Used to record timeouts per channel type */
148 struct ssh_channel_timeout {
149 char *type_pattern;
150 int timeout_secs;
151 };
152
153 /* Master structure for channels state */
154 struct ssh_channels {
155 /*
156 * Pointer to an array containing all allocated channels. The array
157 * is dynamically extended as needed.
158 */
159 Channel **channels;
160
161 /*
162 * Size of the channel array. All slots of the array must always be
163 * initialized (at least the type field); unused slots set to NULL
164 */
165 u_int channels_alloc;
166
167 /*
168 * 'channel_pre*' are called just before IO to add any bits
169 * relevant to channels in the c->io_want bitmasks.
170 *
171 * 'channel_post*': perform any appropriate operations for
172 * channels which have c->io_ready events pending.
173 */
174 chan_fn **channel_pre;
175 chan_fn **channel_post;
176
177 /* -- tcp forwarding */
178 struct permission_set local_perms;
179 struct permission_set remote_perms;
180
181 /* -- X11 forwarding */
182
183 /* Saved X11 local (client) display. */
184 char *x11_saved_display;
185
186 /* Saved X11 authentication protocol name. */
187 char *x11_saved_proto;
188
189 /* Saved X11 authentication data. This is the real data. */
190 char *x11_saved_data;
191 u_int x11_saved_data_len;
192
193 /* Deadline after which all X11 connections are refused */
194 time_t x11_refuse_time;
195
196 /*
197 * Fake X11 authentication data. This is what the server will be
198 * sending us; we should replace any occurrences of this by the
199 * real data.
200 */
201 u_char *x11_fake_data;
202 u_int x11_fake_data_len;
203
204 /* AF_UNSPEC or AF_INET or AF_INET6 */
205 int IPv4or6;
206
207 /* Channel timeouts by type */
208 struct ssh_channel_timeout *timeouts;
209 size_t ntimeouts;
210 /* Global timeout for all OPEN channels */
211 int global_deadline;
212 time_t lastused;
213 };
214
215 /* helper */
216 static void port_open_helper(struct ssh *ssh, Channel *c, char *rtype);
217 static const char *channel_rfwd_bind_host(const char *listen_host);
218
219 /* non-blocking connect helpers */
220 static int connect_next(struct channel_connect *);
221 static void channel_connect_ctx_free(struct channel_connect *);
222 static Channel *rdynamic_connect_prepare(struct ssh *, char *, char *);
223 static int rdynamic_connect_finish(struct ssh *, Channel *);
224
225 /* Setup helper */
226 static void channel_handler_init(struct ssh_channels *sc);
227
228 /* -- channel core */
229
230 void
channel_init_channels(struct ssh * ssh)231 channel_init_channels(struct ssh *ssh)
232 {
233 struct ssh_channels *sc;
234
235 if ((sc = calloc(1, sizeof(*sc))) == NULL)
236 fatal_f("allocation failed");
237 sc->channels_alloc = 10;
238 sc->channels = xcalloc(sc->channels_alloc, sizeof(*sc->channels));
239 sc->IPv4or6 = AF_UNSPEC;
240 channel_handler_init(sc);
241
242 ssh->chanctxt = sc;
243 }
244
245 Channel *
channel_by_id(struct ssh * ssh,int id)246 channel_by_id(struct ssh *ssh, int id)
247 {
248 Channel *c;
249
250 if (id < 0 || (u_int)id >= ssh->chanctxt->channels_alloc) {
251 logit_f("%d: bad id", id);
252 return NULL;
253 }
254 c = ssh->chanctxt->channels[id];
255 if (c == NULL) {
256 logit_f("%d: bad id: channel free", id);
257 return NULL;
258 }
259 return c;
260 }
261
262 Channel *
channel_by_remote_id(struct ssh * ssh,u_int remote_id)263 channel_by_remote_id(struct ssh *ssh, u_int remote_id)
264 {
265 Channel *c;
266 u_int i;
267
268 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) {
269 c = ssh->chanctxt->channels[i];
270 if (c != NULL && c->have_remote_id && c->remote_id == remote_id)
271 return c;
272 }
273 return NULL;
274 }
275
276 /*
277 * Returns the channel if it is allowed to receive protocol messages.
278 * Private channels, like listening sockets, may not receive messages.
279 */
280 Channel *
channel_lookup(struct ssh * ssh,int id)281 channel_lookup(struct ssh *ssh, int id)
282 {
283 Channel *c;
284
285 if ((c = channel_by_id(ssh, id)) == NULL)
286 return NULL;
287
288 switch (c->type) {
289 case SSH_CHANNEL_X11_OPEN:
290 case SSH_CHANNEL_LARVAL:
291 case SSH_CHANNEL_CONNECTING:
292 case SSH_CHANNEL_DYNAMIC:
293 case SSH_CHANNEL_RDYNAMIC_OPEN:
294 case SSH_CHANNEL_RDYNAMIC_FINISH:
295 case SSH_CHANNEL_OPENING:
296 case SSH_CHANNEL_OPEN:
297 case SSH_CHANNEL_ABANDONED:
298 case SSH_CHANNEL_MUX_PROXY:
299 return c;
300 }
301 logit("Non-public channel %d, type %d.", id, c->type);
302 return NULL;
303 }
304
305 /*
306 * Add a timeout for open channels whose c->ctype (or c->xctype if it is set)
307 * match type_pattern.
308 */
309 void
channel_add_timeout(struct ssh * ssh,const char * type_pattern,int timeout_secs)310 channel_add_timeout(struct ssh *ssh, const char *type_pattern,
311 int timeout_secs)
312 {
313 struct ssh_channels *sc = ssh->chanctxt;
314
315 if (strcmp(type_pattern, "global") == 0) {
316 debug2_f("global channel timeout %d seconds", timeout_secs);
317 sc->global_deadline = timeout_secs;
318 return;
319 }
320 debug2_f("channel type \"%s\" timeout %d seconds",
321 type_pattern, timeout_secs);
322 sc->timeouts = xrecallocarray(sc->timeouts, sc->ntimeouts,
323 sc->ntimeouts + 1, sizeof(*sc->timeouts));
324 sc->timeouts[sc->ntimeouts].type_pattern = xstrdup(type_pattern);
325 sc->timeouts[sc->ntimeouts].timeout_secs = timeout_secs;
326 sc->ntimeouts++;
327 }
328
329 /* Clears all previously-added channel timeouts */
330 void
channel_clear_timeouts(struct ssh * ssh)331 channel_clear_timeouts(struct ssh *ssh)
332 {
333 struct ssh_channels *sc = ssh->chanctxt;
334 size_t i;
335
336 debug3_f("clearing");
337 for (i = 0; i < sc->ntimeouts; i++)
338 free(sc->timeouts[i].type_pattern);
339 free(sc->timeouts);
340 sc->timeouts = NULL;
341 sc->ntimeouts = 0;
342 }
343
344 static int
lookup_timeout(struct ssh * ssh,const char * type)345 lookup_timeout(struct ssh *ssh, const char *type)
346 {
347 struct ssh_channels *sc = ssh->chanctxt;
348 size_t i;
349
350 for (i = 0; i < sc->ntimeouts; i++) {
351 if (match_pattern(type, sc->timeouts[i].type_pattern))
352 return sc->timeouts[i].timeout_secs;
353 }
354
355 return 0;
356 }
357
358 /*
359 * Sets "extended type" of a channel; used by session layer to add additional
360 * information about channel types (e.g. shell, login, subsystem) that can then
361 * be used to select timeouts.
362 * Will reset c->inactive_deadline as a side-effect.
363 */
364 void
channel_set_xtype(struct ssh * ssh,int id,const char * xctype)365 channel_set_xtype(struct ssh *ssh, int id, const char *xctype)
366 {
367 Channel *c;
368
369 if ((c = channel_by_id(ssh, id)) == NULL)
370 fatal_f("missing channel %d", id);
371 if (c->xctype != NULL)
372 free(c->xctype);
373 c->xctype = xstrdup(xctype);
374 /* Type has changed, so look up inactivity deadline again */
375 c->inactive_deadline = lookup_timeout(ssh, c->xctype);
376 debug2_f("labeled channel %d as %s (inactive timeout %u)", id, xctype,
377 c->inactive_deadline);
378 }
379
380 /*
381 * update "last used" time on a channel.
382 * NB. nothing else should update lastused except to clear it.
383 */
384 static void
channel_set_used_time(struct ssh * ssh,Channel * c)385 channel_set_used_time(struct ssh *ssh, Channel *c)
386 {
387 ssh->chanctxt->lastused = monotime();
388 if (c != NULL)
389 c->lastused = ssh->chanctxt->lastused;
390 }
391
392 /*
393 * Get the time at which a channel is due to time out for inactivity.
394 * Returns 0 if the channel is not due to time out ever.
395 */
396 static time_t
channel_get_expiry(struct ssh * ssh,Channel * c)397 channel_get_expiry(struct ssh *ssh, Channel *c)
398 {
399 struct ssh_channels *sc = ssh->chanctxt;
400 time_t expiry = 0, channel_expiry;
401
402 if (sc->lastused != 0 && sc->global_deadline != 0)
403 expiry = sc->lastused + sc->global_deadline;
404 if (c->lastused != 0 && c->inactive_deadline != 0) {
405 channel_expiry = c->lastused + c->inactive_deadline;
406 if (expiry == 0 || channel_expiry < expiry)
407 expiry = channel_expiry;
408 }
409 return expiry;
410 }
411
412 /*
413 * Register filedescriptors for a channel, used when allocating a channel or
414 * when the channel consumer/producer is ready, e.g. shell exec'd
415 */
416 static void
channel_register_fds(struct ssh * ssh,Channel * c,int rfd,int wfd,int efd,int extusage,int nonblock,int is_tty)417 channel_register_fds(struct ssh *ssh, Channel *c, int rfd, int wfd, int efd,
418 int extusage, int nonblock, int is_tty)
419 {
420 int val;
421
422 if (rfd != -1)
423 (void)fcntl(rfd, F_SETFD, FD_CLOEXEC);
424 if (wfd != -1 && wfd != rfd)
425 (void)fcntl(wfd, F_SETFD, FD_CLOEXEC);
426 if (efd != -1 && efd != rfd && efd != wfd)
427 (void)fcntl(efd, F_SETFD, FD_CLOEXEC);
428
429 c->rfd = rfd;
430 c->wfd = wfd;
431 c->sock = (rfd == wfd) ? rfd : -1;
432 c->efd = efd;
433 c->extended_usage = extusage;
434
435 if ((c->isatty = is_tty) != 0)
436 debug2("channel %d: rfd %d isatty", c->self, c->rfd);
437 #ifdef _AIX
438 /* XXX: Later AIX versions can't push as much data to tty */
439 c->wfd_isatty = is_tty || isatty(c->wfd);
440 #endif
441
442 /* enable nonblocking mode */
443 c->restore_block = 0;
444 if (nonblock == CHANNEL_NONBLOCK_STDIO) {
445 /*
446 * Special handling for stdio file descriptors: do not set
447 * non-blocking mode if they are TTYs. Otherwise prepare to
448 * restore their blocking state on exit to avoid interfering
449 * with other programs that follow.
450 */
451 if (rfd != -1 && !isatty(rfd) &&
452 (val = fcntl(rfd, F_GETFL)) != -1 && !(val & O_NONBLOCK)) {
453 c->restore_flags[0] = val;
454 c->restore_block |= CHANNEL_RESTORE_RFD;
455 set_nonblock(rfd);
456 }
457 if (wfd != -1 && !isatty(wfd) &&
458 (val = fcntl(wfd, F_GETFL)) != -1 && !(val & O_NONBLOCK)) {
459 c->restore_flags[1] = val;
460 c->restore_block |= CHANNEL_RESTORE_WFD;
461 set_nonblock(wfd);
462 }
463 if (efd != -1 && !isatty(efd) &&
464 (val = fcntl(efd, F_GETFL)) != -1 && !(val & O_NONBLOCK)) {
465 c->restore_flags[2] = val;
466 c->restore_block |= CHANNEL_RESTORE_EFD;
467 set_nonblock(efd);
468 }
469 } else if (nonblock) {
470 if (rfd != -1)
471 set_nonblock(rfd);
472 if (wfd != -1)
473 set_nonblock(wfd);
474 if (efd != -1)
475 set_nonblock(efd);
476 }
477 /* channel might be entering a larval state, so reset global timeout */
478 channel_set_used_time(ssh, NULL);
479 }
480
481 /*
482 * Allocate a new channel object and set its type and socket.
483 */
484 Channel *
channel_new(struct ssh * ssh,char * ctype,int type,int rfd,int wfd,int efd,u_int window,u_int maxpack,int extusage,const char * remote_name,int nonblock)485 channel_new(struct ssh *ssh, char *ctype, int type, int rfd, int wfd, int efd,
486 u_int window, u_int maxpack, int extusage, const char *remote_name,
487 int nonblock)
488 {
489 struct ssh_channels *sc = ssh->chanctxt;
490 u_int i, found = 0;
491 Channel *c;
492 int r;
493
494 /* Try to find a free slot where to put the new channel. */
495 for (i = 0; i < sc->channels_alloc; i++) {
496 if (sc->channels[i] == NULL) {
497 /* Found a free slot. */
498 found = i;
499 break;
500 }
501 }
502 if (i >= sc->channels_alloc) {
503 /*
504 * There are no free slots. Take last+1 slot and expand
505 * the array.
506 */
507 found = sc->channels_alloc;
508 if (sc->channels_alloc > CHANNELS_MAX_CHANNELS)
509 fatal_f("internal error: channels_alloc %d too big",
510 sc->channels_alloc);
511 sc->channels = xrecallocarray(sc->channels, sc->channels_alloc,
512 sc->channels_alloc + 10, sizeof(*sc->channels));
513 sc->channels_alloc += 10;
514 debug2("channel: expanding %d", sc->channels_alloc);
515 }
516 /* Initialize and return new channel. */
517 c = sc->channels[found] = xcalloc(1, sizeof(Channel));
518 if ((c->input = sshbuf_new()) == NULL ||
519 (c->output = sshbuf_new()) == NULL ||
520 (c->extended = sshbuf_new()) == NULL)
521 fatal_f("sshbuf_new failed");
522 if ((r = sshbuf_set_max_size(c->input, CHAN_INPUT_MAX)) != 0)
523 fatal_fr(r, "sshbuf_set_max_size");
524 c->ostate = CHAN_OUTPUT_OPEN;
525 c->istate = CHAN_INPUT_OPEN;
526 channel_register_fds(ssh, c, rfd, wfd, efd, extusage, nonblock, 0);
527 c->self = found;
528 c->type = type;
529 c->ctype = ctype;
530 c->local_window = window;
531 c->local_window_max = window;
532 c->local_maxpacket = maxpack;
533 c->remote_name = xstrdup(remote_name);
534 c->ctl_chan = -1;
535 c->delayed = 1; /* prevent call to channel_post handler */
536 c->inactive_deadline = lookup_timeout(ssh, c->ctype);
537 TAILQ_INIT(&c->status_confirms);
538 debug("channel %d: new %s [%s] (inactive timeout: %u)",
539 found, c->ctype, remote_name, c->inactive_deadline);
540 return c;
541 }
542
543 int
channel_close_fd(struct ssh * ssh,Channel * c,int * fdp)544 channel_close_fd(struct ssh *ssh, Channel *c, int *fdp)
545 {
546 int ret, fd = *fdp;
547
548 if (fd == -1)
549 return 0;
550
551 /* restore blocking */
552 if (*fdp == c->rfd &&
553 (c->restore_block & CHANNEL_RESTORE_RFD) != 0)
554 (void)fcntl(*fdp, F_SETFL, c->restore_flags[0]);
555 else if (*fdp == c->wfd &&
556 (c->restore_block & CHANNEL_RESTORE_WFD) != 0)
557 (void)fcntl(*fdp, F_SETFL, c->restore_flags[1]);
558 else if (*fdp == c->efd &&
559 (c->restore_block & CHANNEL_RESTORE_EFD) != 0)
560 (void)fcntl(*fdp, F_SETFL, c->restore_flags[2]);
561
562 if (*fdp == c->rfd) {
563 c->io_want &= ~SSH_CHAN_IO_RFD;
564 c->io_ready &= ~SSH_CHAN_IO_RFD;
565 c->rfd = -1;
566 c->pfds[0] = -1;
567 }
568 if (*fdp == c->wfd) {
569 c->io_want &= ~SSH_CHAN_IO_WFD;
570 c->io_ready &= ~SSH_CHAN_IO_WFD;
571 c->wfd = -1;
572 c->pfds[1] = -1;
573 }
574 if (*fdp == c->efd) {
575 c->io_want &= ~SSH_CHAN_IO_EFD;
576 c->io_ready &= ~SSH_CHAN_IO_EFD;
577 c->efd = -1;
578 c->pfds[2] = -1;
579 }
580 if (*fdp == c->sock) {
581 c->io_want &= ~SSH_CHAN_IO_SOCK;
582 c->io_ready &= ~SSH_CHAN_IO_SOCK;
583 c->sock = -1;
584 c->pfds[3] = -1;
585 }
586
587 ret = close(fd);
588 *fdp = -1; /* probably redundant */
589 return ret;
590 }
591
592 /* Close all channel fd/socket. */
593 static void
channel_close_fds(struct ssh * ssh,Channel * c)594 channel_close_fds(struct ssh *ssh, Channel *c)
595 {
596 int sock = c->sock, rfd = c->rfd, wfd = c->wfd, efd = c->efd;
597
598 channel_close_fd(ssh, c, &c->sock);
599 if (rfd != sock)
600 channel_close_fd(ssh, c, &c->rfd);
601 if (wfd != sock && wfd != rfd)
602 channel_close_fd(ssh, c, &c->wfd);
603 if (efd != sock && efd != rfd && efd != wfd)
604 channel_close_fd(ssh, c, &c->efd);
605 }
606
607 static void
fwd_perm_clear(struct permission * perm)608 fwd_perm_clear(struct permission *perm)
609 {
610 free(perm->host_to_connect);
611 free(perm->listen_host);
612 free(perm->listen_path);
613 memset(perm, 0, sizeof(*perm));
614 }
615
616 /* Returns an printable name for the specified forwarding permission list */
617 static const char *
fwd_ident(int who,int where)618 fwd_ident(int who, int where)
619 {
620 if (who == FORWARD_ADM) {
621 if (where == FORWARD_LOCAL)
622 return "admin local";
623 else if (where == FORWARD_REMOTE)
624 return "admin remote";
625 } else if (who == FORWARD_USER) {
626 if (where == FORWARD_LOCAL)
627 return "user local";
628 else if (where == FORWARD_REMOTE)
629 return "user remote";
630 }
631 fatal("Unknown forward permission list %d/%d", who, where);
632 }
633
634 /* Returns the forwarding permission list for the specified direction */
635 static struct permission_set *
permission_set_get(struct ssh * ssh,int where)636 permission_set_get(struct ssh *ssh, int where)
637 {
638 struct ssh_channels *sc = ssh->chanctxt;
639
640 switch (where) {
641 case FORWARD_LOCAL:
642 return &sc->local_perms;
643 break;
644 case FORWARD_REMOTE:
645 return &sc->remote_perms;
646 break;
647 default:
648 fatal_f("invalid forwarding direction %d", where);
649 }
650 }
651
652 /* Returns pointers to the specified forwarding list and its element count */
653 static void
permission_set_get_array(struct ssh * ssh,int who,int where,struct permission *** permpp,u_int ** npermpp)654 permission_set_get_array(struct ssh *ssh, int who, int where,
655 struct permission ***permpp, u_int **npermpp)
656 {
657 struct permission_set *pset = permission_set_get(ssh, where);
658
659 switch (who) {
660 case FORWARD_USER:
661 *permpp = &pset->permitted_user;
662 *npermpp = &pset->num_permitted_user;
663 break;
664 case FORWARD_ADM:
665 *permpp = &pset->permitted_admin;
666 *npermpp = &pset->num_permitted_admin;
667 break;
668 default:
669 fatal_f("invalid forwarding client %d", who);
670 }
671 }
672
673 /* Adds an entry to the specified forwarding list */
674 static int
permission_set_add(struct ssh * ssh,int who,int where,const char * host_to_connect,int port_to_connect,const char * listen_host,const char * listen_path,int listen_port,Channel * downstream)675 permission_set_add(struct ssh *ssh, int who, int where,
676 const char *host_to_connect, int port_to_connect,
677 const char *listen_host, const char *listen_path, int listen_port,
678 Channel *downstream)
679 {
680 struct permission **permp;
681 u_int n, *npermp;
682
683 permission_set_get_array(ssh, who, where, &permp, &npermp);
684
685 if (*npermp >= INT_MAX)
686 fatal_f("%s overflow", fwd_ident(who, where));
687
688 *permp = xrecallocarray(*permp, *npermp, *npermp + 1, sizeof(**permp));
689 n = (*npermp)++;
690 #define MAYBE_DUP(s) ((s == NULL) ? NULL : xstrdup(s))
691 (*permp)[n].host_to_connect = MAYBE_DUP(host_to_connect);
692 (*permp)[n].port_to_connect = port_to_connect;
693 (*permp)[n].listen_host = MAYBE_DUP(listen_host);
694 (*permp)[n].listen_path = MAYBE_DUP(listen_path);
695 (*permp)[n].listen_port = listen_port;
696 (*permp)[n].downstream = downstream;
697 #undef MAYBE_DUP
698 return (int)n;
699 }
700
701 static void
mux_remove_remote_forwardings(struct ssh * ssh,Channel * c)702 mux_remove_remote_forwardings(struct ssh *ssh, Channel *c)
703 {
704 struct ssh_channels *sc = ssh->chanctxt;
705 struct permission_set *pset = &sc->local_perms;
706 struct permission *perm;
707 int r;
708 u_int i;
709
710 for (i = 0; i < pset->num_permitted_user; i++) {
711 perm = &pset->permitted_user[i];
712 if (perm->downstream != c)
713 continue;
714
715 /* cancel on the server, since mux client is gone */
716 debug("channel %d: cleanup remote forward for %s:%u",
717 c->self, perm->listen_host, perm->listen_port);
718 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 ||
719 (r = sshpkt_put_cstring(ssh,
720 "cancel-tcpip-forward")) != 0 ||
721 (r = sshpkt_put_u8(ssh, 0)) != 0 ||
722 (r = sshpkt_put_cstring(ssh,
723 channel_rfwd_bind_host(perm->listen_host))) != 0 ||
724 (r = sshpkt_put_u32(ssh, perm->listen_port)) != 0 ||
725 (r = sshpkt_send(ssh)) != 0) {
726 fatal_fr(r, "channel %i", c->self);
727 }
728 fwd_perm_clear(perm); /* unregister */
729 }
730 }
731
732 /* Free the channel and close its fd/socket. */
733 void
channel_free(struct ssh * ssh,Channel * c)734 channel_free(struct ssh *ssh, Channel *c)
735 {
736 struct ssh_channels *sc = ssh->chanctxt;
737 char *s;
738 u_int i, n;
739 Channel *other;
740 struct channel_confirm *cc;
741
742 for (n = 0, i = 0; i < sc->channels_alloc; i++) {
743 if ((other = sc->channels[i]) == NULL)
744 continue;
745 n++;
746 /* detach from mux client and prepare for closing */
747 if (c->type == SSH_CHANNEL_MUX_CLIENT &&
748 other->type == SSH_CHANNEL_MUX_PROXY &&
749 other->mux_ctx == c) {
750 other->mux_ctx = NULL;
751 other->type = SSH_CHANNEL_OPEN;
752 other->istate = CHAN_INPUT_CLOSED;
753 other->ostate = CHAN_OUTPUT_CLOSED;
754 }
755 }
756 debug("channel %d: free: %s, nchannels %u", c->self,
757 c->remote_name ? c->remote_name : "???", n);
758
759 if (c->type == SSH_CHANNEL_MUX_CLIENT) {
760 mux_remove_remote_forwardings(ssh, c);
761 free(c->mux_ctx);
762 c->mux_ctx = NULL;
763 } else if (c->type == SSH_CHANNEL_MUX_LISTENER) {
764 free(c->mux_ctx);
765 c->mux_ctx = NULL;
766 }
767
768 if (log_level_get() >= SYSLOG_LEVEL_DEBUG3) {
769 s = channel_open_message(ssh);
770 debug3("channel %d: status: %s", c->self, s);
771 free(s);
772 }
773
774 channel_close_fds(ssh, c);
775 sshbuf_free(c->input);
776 sshbuf_free(c->output);
777 sshbuf_free(c->extended);
778 c->input = c->output = c->extended = NULL;
779 free(c->remote_name);
780 c->remote_name = NULL;
781 free(c->path);
782 c->path = NULL;
783 free(c->listening_addr);
784 c->listening_addr = NULL;
785 free(c->xctype);
786 c->xctype = NULL;
787 while ((cc = TAILQ_FIRST(&c->status_confirms)) != NULL) {
788 if (cc->abandon_cb != NULL)
789 cc->abandon_cb(ssh, c, cc->ctx);
790 TAILQ_REMOVE(&c->status_confirms, cc, entry);
791 freezero(cc, sizeof(*cc));
792 }
793 if (c->filter_cleanup != NULL && c->filter_ctx != NULL)
794 c->filter_cleanup(ssh, c->self, c->filter_ctx);
795 sc->channels[c->self] = NULL;
796 freezero(c, sizeof(*c));
797 }
798
799 void
channel_free_all(struct ssh * ssh)800 channel_free_all(struct ssh *ssh)
801 {
802 u_int i;
803 struct ssh_channels *sc = ssh->chanctxt;
804
805 for (i = 0; i < sc->channels_alloc; i++)
806 if (sc->channels[i] != NULL)
807 channel_free(ssh, sc->channels[i]);
808
809 free(sc->channels);
810 sc->channels = NULL;
811 sc->channels_alloc = 0;
812
813 free(sc->x11_saved_display);
814 sc->x11_saved_display = NULL;
815
816 free(sc->x11_saved_proto);
817 sc->x11_saved_proto = NULL;
818
819 free(sc->x11_saved_data);
820 sc->x11_saved_data = NULL;
821 sc->x11_saved_data_len = 0;
822
823 free(sc->x11_fake_data);
824 sc->x11_fake_data = NULL;
825 sc->x11_fake_data_len = 0;
826 }
827
828 /*
829 * Closes the sockets/fds of all channels. This is used to close extra file
830 * descriptors after a fork.
831 */
832 void
channel_close_all(struct ssh * ssh)833 channel_close_all(struct ssh *ssh)
834 {
835 u_int i;
836
837 for (i = 0; i < ssh->chanctxt->channels_alloc; i++)
838 if (ssh->chanctxt->channels[i] != NULL)
839 channel_close_fds(ssh, ssh->chanctxt->channels[i]);
840 }
841
842 /*
843 * Stop listening to channels.
844 */
845 void
channel_stop_listening(struct ssh * ssh)846 channel_stop_listening(struct ssh *ssh)
847 {
848 u_int i;
849 Channel *c;
850
851 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) {
852 c = ssh->chanctxt->channels[i];
853 if (c != NULL) {
854 switch (c->type) {
855 case SSH_CHANNEL_AUTH_SOCKET:
856 case SSH_CHANNEL_PORT_LISTENER:
857 case SSH_CHANNEL_RPORT_LISTENER:
858 case SSH_CHANNEL_X11_LISTENER:
859 case SSH_CHANNEL_UNIX_LISTENER:
860 case SSH_CHANNEL_RUNIX_LISTENER:
861 channel_close_fd(ssh, c, &c->sock);
862 channel_free(ssh, c);
863 break;
864 }
865 }
866 }
867 }
868
869 /*
870 * Returns true if no channel has too much buffered data, and false if one or
871 * more channel is overfull.
872 */
873 int
channel_not_very_much_buffered_data(struct ssh * ssh)874 channel_not_very_much_buffered_data(struct ssh *ssh)
875 {
876 u_int i;
877 u_int maxsize = ssh_packet_get_maxsize(ssh);
878 Channel *c;
879
880 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) {
881 c = ssh->chanctxt->channels[i];
882 if (c == NULL || c->type != SSH_CHANNEL_OPEN)
883 continue;
884 if (sshbuf_len(c->output) > maxsize) {
885 debug2("channel %d: big output buffer %zu > %u",
886 c->self, sshbuf_len(c->output), maxsize);
887 return 0;
888 }
889 }
890 return 1;
891 }
892
893 /* Returns true if any channel is still open. */
894 int
channel_still_open(struct ssh * ssh)895 channel_still_open(struct ssh *ssh)
896 {
897 u_int i;
898 Channel *c;
899
900 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) {
901 c = ssh->chanctxt->channels[i];
902 if (c == NULL)
903 continue;
904 switch (c->type) {
905 case SSH_CHANNEL_X11_LISTENER:
906 case SSH_CHANNEL_PORT_LISTENER:
907 case SSH_CHANNEL_RPORT_LISTENER:
908 case SSH_CHANNEL_MUX_LISTENER:
909 case SSH_CHANNEL_CLOSED:
910 case SSH_CHANNEL_AUTH_SOCKET:
911 case SSH_CHANNEL_DYNAMIC:
912 case SSH_CHANNEL_RDYNAMIC_OPEN:
913 case SSH_CHANNEL_CONNECTING:
914 case SSH_CHANNEL_ZOMBIE:
915 case SSH_CHANNEL_ABANDONED:
916 case SSH_CHANNEL_UNIX_LISTENER:
917 case SSH_CHANNEL_RUNIX_LISTENER:
918 continue;
919 case SSH_CHANNEL_LARVAL:
920 continue;
921 case SSH_CHANNEL_OPENING:
922 case SSH_CHANNEL_OPEN:
923 case SSH_CHANNEL_RDYNAMIC_FINISH:
924 case SSH_CHANNEL_X11_OPEN:
925 case SSH_CHANNEL_MUX_CLIENT:
926 case SSH_CHANNEL_MUX_PROXY:
927 return 1;
928 default:
929 fatal_f("bad channel type %d", c->type);
930 /* NOTREACHED */
931 }
932 }
933 return 0;
934 }
935
936 /* Returns true if a channel with a TTY is open. */
937 int
channel_tty_open(struct ssh * ssh)938 channel_tty_open(struct ssh *ssh)
939 {
940 u_int i;
941 Channel *c;
942
943 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) {
944 c = ssh->chanctxt->channels[i];
945 if (c == NULL || c->type != SSH_CHANNEL_OPEN)
946 continue;
947 if (c->client_tty)
948 return 1;
949 }
950 return 0;
951 }
952
953 /* Returns the id of an open channel suitable for keepaliving */
954 int
channel_find_open(struct ssh * ssh)955 channel_find_open(struct ssh *ssh)
956 {
957 u_int i;
958 Channel *c;
959
960 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) {
961 c = ssh->chanctxt->channels[i];
962 if (c == NULL || !c->have_remote_id)
963 continue;
964 switch (c->type) {
965 case SSH_CHANNEL_CLOSED:
966 case SSH_CHANNEL_DYNAMIC:
967 case SSH_CHANNEL_RDYNAMIC_OPEN:
968 case SSH_CHANNEL_RDYNAMIC_FINISH:
969 case SSH_CHANNEL_X11_LISTENER:
970 case SSH_CHANNEL_PORT_LISTENER:
971 case SSH_CHANNEL_RPORT_LISTENER:
972 case SSH_CHANNEL_MUX_LISTENER:
973 case SSH_CHANNEL_MUX_CLIENT:
974 case SSH_CHANNEL_MUX_PROXY:
975 case SSH_CHANNEL_OPENING:
976 case SSH_CHANNEL_CONNECTING:
977 case SSH_CHANNEL_ZOMBIE:
978 case SSH_CHANNEL_ABANDONED:
979 case SSH_CHANNEL_UNIX_LISTENER:
980 case SSH_CHANNEL_RUNIX_LISTENER:
981 continue;
982 case SSH_CHANNEL_LARVAL:
983 case SSH_CHANNEL_AUTH_SOCKET:
984 case SSH_CHANNEL_OPEN:
985 case SSH_CHANNEL_X11_OPEN:
986 return i;
987 default:
988 fatal_f("bad channel type %d", c->type);
989 /* NOTREACHED */
990 }
991 }
992 return -1;
993 }
994
995 /* Returns the state of the channel's extended usage flag */
996 const char *
channel_format_extended_usage(const Channel * c)997 channel_format_extended_usage(const Channel *c)
998 {
999 if (c->efd == -1)
1000 return "closed";
1001
1002 switch (c->extended_usage) {
1003 case CHAN_EXTENDED_WRITE:
1004 return "write";
1005 case CHAN_EXTENDED_READ:
1006 return "read";
1007 case CHAN_EXTENDED_IGNORE:
1008 return "ignore";
1009 default:
1010 return "UNKNOWN";
1011 }
1012 }
1013
1014 static char *
channel_format_status(const Channel * c)1015 channel_format_status(const Channel *c)
1016 {
1017 char *ret = NULL;
1018
1019 xasprintf(&ret, "t%d [%s] %s%u i%u/%zu o%u/%zu e[%s]/%zu "
1020 "fd %d/%d/%d sock %d cc %d io 0x%02x/0x%02x",
1021 c->type, c->xctype != NULL ? c->xctype : c->ctype,
1022 c->have_remote_id ? "r" : "nr", c->remote_id,
1023 c->istate, sshbuf_len(c->input),
1024 c->ostate, sshbuf_len(c->output),
1025 channel_format_extended_usage(c), sshbuf_len(c->extended),
1026 c->rfd, c->wfd, c->efd, c->sock, c->ctl_chan,
1027 c->io_want, c->io_ready);
1028 return ret;
1029 }
1030
1031 /*
1032 * Returns a message describing the currently open forwarded connections,
1033 * suitable for sending to the client. The message contains crlf pairs for
1034 * newlines.
1035 */
1036 char *
channel_open_message(struct ssh * ssh)1037 channel_open_message(struct ssh *ssh)
1038 {
1039 struct sshbuf *buf;
1040 Channel *c;
1041 u_int i;
1042 int r;
1043 char *cp, *ret;
1044
1045 if ((buf = sshbuf_new()) == NULL)
1046 fatal_f("sshbuf_new");
1047 if ((r = sshbuf_putf(buf,
1048 "The following connections are open:\r\n")) != 0)
1049 fatal_fr(r, "sshbuf_putf");
1050 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) {
1051 c = ssh->chanctxt->channels[i];
1052 if (c == NULL)
1053 continue;
1054 switch (c->type) {
1055 case SSH_CHANNEL_X11_LISTENER:
1056 case SSH_CHANNEL_PORT_LISTENER:
1057 case SSH_CHANNEL_RPORT_LISTENER:
1058 case SSH_CHANNEL_CLOSED:
1059 case SSH_CHANNEL_AUTH_SOCKET:
1060 case SSH_CHANNEL_ZOMBIE:
1061 case SSH_CHANNEL_ABANDONED:
1062 case SSH_CHANNEL_MUX_LISTENER:
1063 case SSH_CHANNEL_UNIX_LISTENER:
1064 case SSH_CHANNEL_RUNIX_LISTENER:
1065 continue;
1066 case SSH_CHANNEL_LARVAL:
1067 case SSH_CHANNEL_OPENING:
1068 case SSH_CHANNEL_CONNECTING:
1069 case SSH_CHANNEL_DYNAMIC:
1070 case SSH_CHANNEL_RDYNAMIC_OPEN:
1071 case SSH_CHANNEL_RDYNAMIC_FINISH:
1072 case SSH_CHANNEL_OPEN:
1073 case SSH_CHANNEL_X11_OPEN:
1074 case SSH_CHANNEL_MUX_PROXY:
1075 case SSH_CHANNEL_MUX_CLIENT:
1076 cp = channel_format_status(c);
1077 if ((r = sshbuf_putf(buf, " #%d %.300s (%s)\r\n",
1078 c->self, c->remote_name, cp)) != 0) {
1079 free(cp);
1080 fatal_fr(r, "sshbuf_putf");
1081 }
1082 free(cp);
1083 continue;
1084 default:
1085 fatal_f("bad channel type %d", c->type);
1086 /* NOTREACHED */
1087 }
1088 }
1089 if ((ret = sshbuf_dup_string(buf)) == NULL)
1090 fatal_f("sshbuf_dup_string");
1091 sshbuf_free(buf);
1092 return ret;
1093 }
1094
1095 static void
open_preamble(struct ssh * ssh,const char * where,Channel * c,const char * type)1096 open_preamble(struct ssh *ssh, const char *where, Channel *c, const char *type)
1097 {
1098 int r;
1099
1100 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN)) != 0 ||
1101 (r = sshpkt_put_cstring(ssh, type)) != 0 ||
1102 (r = sshpkt_put_u32(ssh, c->self)) != 0 ||
1103 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 ||
1104 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0) {
1105 fatal_r(r, "%s: channel %i: open", where, c->self);
1106 }
1107 }
1108
1109 void
channel_send_open(struct ssh * ssh,int id)1110 channel_send_open(struct ssh *ssh, int id)
1111 {
1112 Channel *c = channel_lookup(ssh, id);
1113 int r;
1114
1115 if (c == NULL) {
1116 logit("channel_send_open: %d: bad id", id);
1117 return;
1118 }
1119 debug2("channel %d: send open", id);
1120 open_preamble(ssh, __func__, c, c->ctype);
1121 if ((r = sshpkt_send(ssh)) != 0)
1122 fatal_fr(r, "channel %i", c->self);
1123 }
1124
1125 void
channel_request_start(struct ssh * ssh,int id,char * service,int wantconfirm)1126 channel_request_start(struct ssh *ssh, int id, char *service, int wantconfirm)
1127 {
1128 Channel *c = channel_lookup(ssh, id);
1129 int r;
1130
1131 if (c == NULL) {
1132 logit_f("%d: unknown channel id", id);
1133 return;
1134 }
1135 if (!c->have_remote_id)
1136 fatal_f("channel %d: no remote id", c->self);
1137
1138 debug2("channel %d: request %s confirm %d", id, service, wantconfirm);
1139 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_REQUEST)) != 0 ||
1140 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 ||
1141 (r = sshpkt_put_cstring(ssh, service)) != 0 ||
1142 (r = sshpkt_put_u8(ssh, wantconfirm)) != 0) {
1143 fatal_fr(r, "channel %i", c->self);
1144 }
1145 }
1146
1147 void
channel_register_status_confirm(struct ssh * ssh,int id,channel_confirm_cb * cb,channel_confirm_abandon_cb * abandon_cb,void * ctx)1148 channel_register_status_confirm(struct ssh *ssh, int id,
1149 channel_confirm_cb *cb, channel_confirm_abandon_cb *abandon_cb, void *ctx)
1150 {
1151 struct channel_confirm *cc;
1152 Channel *c;
1153
1154 if ((c = channel_lookup(ssh, id)) == NULL)
1155 fatal_f("%d: bad id", id);
1156
1157 cc = xcalloc(1, sizeof(*cc));
1158 cc->cb = cb;
1159 cc->abandon_cb = abandon_cb;
1160 cc->ctx = ctx;
1161 TAILQ_INSERT_TAIL(&c->status_confirms, cc, entry);
1162 }
1163
1164 void
channel_register_open_confirm(struct ssh * ssh,int id,channel_open_fn * fn,void * ctx)1165 channel_register_open_confirm(struct ssh *ssh, int id,
1166 channel_open_fn *fn, void *ctx)
1167 {
1168 Channel *c = channel_lookup(ssh, id);
1169
1170 if (c == NULL) {
1171 logit_f("%d: bad id", id);
1172 return;
1173 }
1174 c->open_confirm = fn;
1175 c->open_confirm_ctx = ctx;
1176 }
1177
1178 void
channel_register_cleanup(struct ssh * ssh,int id,channel_callback_fn * fn,int do_close)1179 channel_register_cleanup(struct ssh *ssh, int id,
1180 channel_callback_fn *fn, int do_close)
1181 {
1182 Channel *c = channel_by_id(ssh, id);
1183
1184 if (c == NULL) {
1185 logit_f("%d: bad id", id);
1186 return;
1187 }
1188 c->detach_user = fn;
1189 c->detach_close = do_close;
1190 }
1191
1192 void
channel_cancel_cleanup(struct ssh * ssh,int id)1193 channel_cancel_cleanup(struct ssh *ssh, int id)
1194 {
1195 Channel *c = channel_by_id(ssh, id);
1196
1197 if (c == NULL) {
1198 logit_f("%d: bad id", id);
1199 return;
1200 }
1201 c->detach_user = NULL;
1202 c->detach_close = 0;
1203 }
1204
1205 void
channel_register_filter(struct ssh * ssh,int id,channel_infilter_fn * ifn,channel_outfilter_fn * ofn,channel_filter_cleanup_fn * cfn,void * ctx)1206 channel_register_filter(struct ssh *ssh, int id, channel_infilter_fn *ifn,
1207 channel_outfilter_fn *ofn, channel_filter_cleanup_fn *cfn, void *ctx)
1208 {
1209 Channel *c = channel_lookup(ssh, id);
1210
1211 if (c == NULL) {
1212 logit_f("%d: bad id", id);
1213 return;
1214 }
1215 c->input_filter = ifn;
1216 c->output_filter = ofn;
1217 c->filter_ctx = ctx;
1218 c->filter_cleanup = cfn;
1219 }
1220
1221 void
channel_set_fds(struct ssh * ssh,int id,int rfd,int wfd,int efd,int extusage,int nonblock,int is_tty,u_int window_max)1222 channel_set_fds(struct ssh *ssh, int id, int rfd, int wfd, int efd,
1223 int extusage, int nonblock, int is_tty, u_int window_max)
1224 {
1225 Channel *c = channel_lookup(ssh, id);
1226 int r;
1227
1228 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
1229 fatal("channel_activate for non-larval channel %d.", id);
1230 if (!c->have_remote_id)
1231 fatal_f("channel %d: no remote id", c->self);
1232
1233 channel_register_fds(ssh, c, rfd, wfd, efd, extusage, nonblock, is_tty);
1234 c->type = SSH_CHANNEL_OPEN;
1235 channel_set_used_time(ssh, c);
1236 c->local_window = c->local_window_max = window_max;
1237
1238 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST)) != 0 ||
1239 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 ||
1240 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 ||
1241 (r = sshpkt_send(ssh)) != 0)
1242 fatal_fr(r, "channel %i", c->self);
1243 }
1244
1245 static void
channel_pre_listener(struct ssh * ssh,Channel * c)1246 channel_pre_listener(struct ssh *ssh, Channel *c)
1247 {
1248 c->io_want = SSH_CHAN_IO_SOCK_R;
1249 }
1250
1251 static void
channel_pre_connecting(struct ssh * ssh,Channel * c)1252 channel_pre_connecting(struct ssh *ssh, Channel *c)
1253 {
1254 debug3("channel %d: waiting for connection", c->self);
1255 c->io_want = SSH_CHAN_IO_SOCK_W;
1256 }
1257
1258 static void
channel_pre_open(struct ssh * ssh,Channel * c)1259 channel_pre_open(struct ssh *ssh, Channel *c)
1260 {
1261 c->io_want = 0;
1262 if (c->istate == CHAN_INPUT_OPEN &&
1263 c->remote_window > 0 &&
1264 sshbuf_len(c->input) < c->remote_window &&
1265 sshbuf_check_reserve(c->input, CHAN_RBUF) == 0)
1266 c->io_want |= SSH_CHAN_IO_RFD;
1267 if (c->ostate == CHAN_OUTPUT_OPEN ||
1268 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
1269 if (sshbuf_len(c->output) > 0) {
1270 c->io_want |= SSH_CHAN_IO_WFD;
1271 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
1272 if (CHANNEL_EFD_OUTPUT_ACTIVE(c))
1273 debug2("channel %d: "
1274 "obuf_empty delayed efd %d/(%zu)", c->self,
1275 c->efd, sshbuf_len(c->extended));
1276 else
1277 chan_obuf_empty(ssh, c);
1278 }
1279 }
1280 /** XXX check close conditions, too */
1281 if (c->efd != -1 && !(c->istate == CHAN_INPUT_CLOSED &&
1282 c->ostate == CHAN_OUTPUT_CLOSED)) {
1283 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1284 sshbuf_len(c->extended) > 0)
1285 c->io_want |= SSH_CHAN_IO_EFD_W;
1286 else if (c->efd != -1 && !(c->flags & CHAN_EOF_SENT) &&
1287 (c->extended_usage == CHAN_EXTENDED_READ ||
1288 c->extended_usage == CHAN_EXTENDED_IGNORE) &&
1289 sshbuf_len(c->extended) < c->remote_window)
1290 c->io_want |= SSH_CHAN_IO_EFD_R;
1291 }
1292 /* XXX: What about efd? races? */
1293 }
1294
1295 /*
1296 * This is a special state for X11 authentication spoofing. An opened X11
1297 * connection (when authentication spoofing is being done) remains in this
1298 * state until the first packet has been completely read. The authentication
1299 * data in that packet is then substituted by the real data if it matches the
1300 * fake data, and the channel is put into normal mode.
1301 * XXX All this happens at the client side.
1302 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
1303 */
1304 static int
x11_open_helper(struct ssh * ssh,struct sshbuf * b)1305 x11_open_helper(struct ssh *ssh, struct sshbuf *b)
1306 {
1307 struct ssh_channels *sc = ssh->chanctxt;
1308 u_char *ucp;
1309 u_int proto_len, data_len;
1310
1311 /* Is this being called after the refusal deadline? */
1312 if (sc->x11_refuse_time != 0 &&
1313 monotime() >= sc->x11_refuse_time) {
1314 verbose("Rejected X11 connection after ForwardX11Timeout "
1315 "expired");
1316 return -1;
1317 }
1318
1319 /* Check if the fixed size part of the packet is in buffer. */
1320 if (sshbuf_len(b) < 12)
1321 return 0;
1322
1323 /* Parse the lengths of variable-length fields. */
1324 ucp = sshbuf_mutable_ptr(b);
1325 if (ucp[0] == 0x42) { /* Byte order MSB first. */
1326 proto_len = 256 * ucp[6] + ucp[7];
1327 data_len = 256 * ucp[8] + ucp[9];
1328 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
1329 proto_len = ucp[6] + 256 * ucp[7];
1330 data_len = ucp[8] + 256 * ucp[9];
1331 } else {
1332 debug2("Initial X11 packet contains bad byte order byte: 0x%x",
1333 ucp[0]);
1334 return -1;
1335 }
1336
1337 /* Check if the whole packet is in buffer. */
1338 if (sshbuf_len(b) <
1339 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
1340 return 0;
1341
1342 /* Check if authentication protocol matches. */
1343 if (proto_len != strlen(sc->x11_saved_proto) ||
1344 memcmp(ucp + 12, sc->x11_saved_proto, proto_len) != 0) {
1345 debug2("X11 connection uses different authentication protocol.");
1346 return -1;
1347 }
1348 /* Check if authentication data matches our fake data. */
1349 if (data_len != sc->x11_fake_data_len ||
1350 timingsafe_bcmp(ucp + 12 + ((proto_len + 3) & ~3),
1351 sc->x11_fake_data, sc->x11_fake_data_len) != 0) {
1352 debug2("X11 auth data does not match fake data.");
1353 return -1;
1354 }
1355 /* Check fake data length */
1356 if (sc->x11_fake_data_len != sc->x11_saved_data_len) {
1357 error("X11 fake_data_len %d != saved_data_len %d",
1358 sc->x11_fake_data_len, sc->x11_saved_data_len);
1359 return -1;
1360 }
1361 /*
1362 * Received authentication protocol and data match
1363 * our fake data. Substitute the fake data with real
1364 * data.
1365 */
1366 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
1367 sc->x11_saved_data, sc->x11_saved_data_len);
1368 return 1;
1369 }
1370
1371 void
channel_force_close(struct ssh * ssh,Channel * c,int abandon)1372 channel_force_close(struct ssh *ssh, Channel *c, int abandon)
1373 {
1374 debug3_f("channel %d: forcibly closing", c->self);
1375 if (c->istate == CHAN_INPUT_OPEN)
1376 chan_read_failed(ssh, c);
1377 if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1378 sshbuf_reset(c->input);
1379 chan_ibuf_empty(ssh, c);
1380 }
1381 if (c->ostate == CHAN_OUTPUT_OPEN ||
1382 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
1383 sshbuf_reset(c->output);
1384 chan_write_failed(ssh, c);
1385 }
1386 if (c->detach_user)
1387 c->detach_user(ssh, c->self, 1, NULL);
1388 if (c->efd != -1)
1389 channel_close_fd(ssh, c, &c->efd);
1390 if (abandon)
1391 c->type = SSH_CHANNEL_ABANDONED;
1392 /* exempt from inactivity timeouts */
1393 c->inactive_deadline = 0;
1394 c->lastused = 0;
1395 }
1396
1397 static void
channel_pre_x11_open(struct ssh * ssh,Channel * c)1398 channel_pre_x11_open(struct ssh *ssh, Channel *c)
1399 {
1400 int ret = x11_open_helper(ssh, c->output);
1401
1402 /* c->force_drain = 1; */
1403
1404 if (ret == 1) {
1405 c->type = SSH_CHANNEL_OPEN;
1406 channel_set_used_time(ssh, c);
1407 channel_pre_open(ssh, c);
1408 } else if (ret == -1) {
1409 logit("X11 connection rejected because of wrong "
1410 "authentication.");
1411 debug2("X11 rejected %d i%d/o%d",
1412 c->self, c->istate, c->ostate);
1413 channel_force_close(ssh, c, 0);
1414 }
1415 }
1416
1417 static void
channel_pre_mux_client(struct ssh * ssh,Channel * c)1418 channel_pre_mux_client(struct ssh *ssh, Channel *c)
1419 {
1420 c->io_want = 0;
1421 if (c->istate == CHAN_INPUT_OPEN && !c->mux_pause &&
1422 sshbuf_check_reserve(c->input, CHAN_RBUF) == 0)
1423 c->io_want |= SSH_CHAN_IO_RFD;
1424 if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1425 /* clear buffer immediately (discard any partial packet) */
1426 sshbuf_reset(c->input);
1427 chan_ibuf_empty(ssh, c);
1428 /* Start output drain. XXX just kill chan? */
1429 chan_rcvd_oclose(ssh, c);
1430 }
1431 if (c->ostate == CHAN_OUTPUT_OPEN ||
1432 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
1433 if (sshbuf_len(c->output) > 0)
1434 c->io_want |= SSH_CHAN_IO_WFD;
1435 else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN)
1436 chan_obuf_empty(ssh, c);
1437 }
1438 }
1439
1440 /* try to decode a socks4 header */
1441 static int
channel_decode_socks4(Channel * c,struct sshbuf * input,struct sshbuf * output)1442 channel_decode_socks4(Channel *c, struct sshbuf *input, struct sshbuf *output)
1443 {
1444 const u_char *p;
1445 char *host;
1446 u_int len, have, i, found, need;
1447 char username[256];
1448 struct {
1449 u_int8_t version;
1450 u_int8_t command;
1451 u_int16_t dest_port;
1452 struct in_addr dest_addr;
1453 } s4_req, s4_rsp;
1454 int r;
1455
1456 debug2("channel %d: decode socks4", c->self);
1457
1458 have = sshbuf_len(input);
1459 len = sizeof(s4_req);
1460 if (have < len)
1461 return 0;
1462 p = sshbuf_ptr(input);
1463
1464 need = 1;
1465 /* SOCKS4A uses an invalid IP address 0.0.0.x */
1466 if (p[4] == 0 && p[5] == 0 && p[6] == 0 && p[7] != 0) {
1467 debug2("channel %d: socks4a request", c->self);
1468 /* ... and needs an extra string (the hostname) */
1469 need = 2;
1470 }
1471 /* Check for terminating NUL on the string(s) */
1472 for (found = 0, i = len; i < have; i++) {
1473 if (p[i] == '\0') {
1474 found++;
1475 if (found == need)
1476 break;
1477 }
1478 if (i > 1024) {
1479 /* the peer is probably sending garbage */
1480 debug("channel %d: decode socks4: too long",
1481 c->self);
1482 return -1;
1483 }
1484 }
1485 if (found < need)
1486 return 0;
1487 if ((r = sshbuf_get(input, &s4_req.version, 1)) != 0 ||
1488 (r = sshbuf_get(input, &s4_req.command, 1)) != 0 ||
1489 (r = sshbuf_get(input, &s4_req.dest_port, 2)) != 0 ||
1490 (r = sshbuf_get(input, &s4_req.dest_addr, 4)) != 0) {
1491 debug_r(r, "channels %d: decode socks4", c->self);
1492 return -1;
1493 }
1494 have = sshbuf_len(input);
1495 p = sshbuf_ptr(input);
1496 if (memchr(p, '\0', have) == NULL) {
1497 error("channel %d: decode socks4: unterminated user", c->self);
1498 return -1;
1499 }
1500 len = strlen(p);
1501 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
1502 len++; /* trailing '\0' */
1503 strlcpy(username, p, sizeof(username));
1504 if ((r = sshbuf_consume(input, len)) != 0)
1505 fatal_fr(r, "channel %d: consume", c->self);
1506 free(c->path);
1507 c->path = NULL;
1508 if (need == 1) { /* SOCKS4: one string */
1509 host = inet_ntoa(s4_req.dest_addr);
1510 c->path = xstrdup(host);
1511 } else { /* SOCKS4A: two strings */
1512 have = sshbuf_len(input);
1513 p = sshbuf_ptr(input);
1514 if (memchr(p, '\0', have) == NULL) {
1515 error("channel %d: decode socks4a: host not nul "
1516 "terminated", c->self);
1517 return -1;
1518 }
1519 len = strlen(p);
1520 debug2("channel %d: decode socks4a: host %s/%d",
1521 c->self, p, len);
1522 len++; /* trailing '\0' */
1523 if (len > NI_MAXHOST) {
1524 error("channel %d: hostname \"%.100s\" too long",
1525 c->self, p);
1526 return -1;
1527 }
1528 c->path = xstrdup(p);
1529 if ((r = sshbuf_consume(input, len)) != 0)
1530 fatal_fr(r, "channel %d: consume", c->self);
1531 }
1532 c->host_port = ntohs(s4_req.dest_port);
1533
1534 debug2("channel %d: dynamic request: socks4 host %s port %u command %u",
1535 c->self, c->path, c->host_port, s4_req.command);
1536
1537 if (s4_req.command != 1) {
1538 debug("channel %d: cannot handle: %s cn %d",
1539 c->self, need == 1 ? "SOCKS4" : "SOCKS4A", s4_req.command);
1540 return -1;
1541 }
1542 s4_rsp.version = 0; /* vn: 0 for reply */
1543 s4_rsp.command = 90; /* cd: req granted */
1544 s4_rsp.dest_port = 0; /* ignored */
1545 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
1546 if ((r = sshbuf_put(output, &s4_rsp, sizeof(s4_rsp))) != 0)
1547 fatal_fr(r, "channel %d: append reply", c->self);
1548 return 1;
1549 }
1550
1551 /* try to decode a socks5 header */
1552 #define SSH_SOCKS5_AUTHDONE 0x1000
1553 #define SSH_SOCKS5_NOAUTH 0x00
1554 #define SSH_SOCKS5_IPV4 0x01
1555 #define SSH_SOCKS5_DOMAIN 0x03
1556 #define SSH_SOCKS5_IPV6 0x04
1557 #define SSH_SOCKS5_CONNECT 0x01
1558 #define SSH_SOCKS5_SUCCESS 0x00
1559
1560 static int
channel_decode_socks5(Channel * c,struct sshbuf * input,struct sshbuf * output)1561 channel_decode_socks5(Channel *c, struct sshbuf *input, struct sshbuf *output)
1562 {
1563 /* XXX use get/put_u8 instead of trusting struct padding */
1564 struct {
1565 u_int8_t version;
1566 u_int8_t command;
1567 u_int8_t reserved;
1568 u_int8_t atyp;
1569 } s5_req, s5_rsp;
1570 u_int16_t dest_port;
1571 char dest_addr[255+1], ntop[INET6_ADDRSTRLEN];
1572 const u_char *p;
1573 u_int have, need, i, found, nmethods, addrlen, af;
1574 int r;
1575
1576 debug2("channel %d: decode socks5", c->self);
1577 p = sshbuf_ptr(input);
1578 if (p[0] != 0x05)
1579 return -1;
1580 have = sshbuf_len(input);
1581 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) {
1582 /* format: ver | nmethods | methods */
1583 if (have < 2)
1584 return 0;
1585 nmethods = p[1];
1586 if (have < nmethods + 2)
1587 return 0;
1588 /* look for method: "NO AUTHENTICATION REQUIRED" */
1589 for (found = 0, i = 2; i < nmethods + 2; i++) {
1590 if (p[i] == SSH_SOCKS5_NOAUTH) {
1591 found = 1;
1592 break;
1593 }
1594 }
1595 if (!found) {
1596 debug("channel %d: method SSH_SOCKS5_NOAUTH not found",
1597 c->self);
1598 return -1;
1599 }
1600 if ((r = sshbuf_consume(input, nmethods + 2)) != 0)
1601 fatal_fr(r, "channel %d: consume", c->self);
1602 /* version, method */
1603 if ((r = sshbuf_put_u8(output, 0x05)) != 0 ||
1604 (r = sshbuf_put_u8(output, SSH_SOCKS5_NOAUTH)) != 0)
1605 fatal_fr(r, "channel %d: append reply", c->self);
1606 c->flags |= SSH_SOCKS5_AUTHDONE;
1607 debug2("channel %d: socks5 auth done", c->self);
1608 return 0; /* need more */
1609 }
1610 debug2("channel %d: socks5 post auth", c->self);
1611 if (have < sizeof(s5_req)+1)
1612 return 0; /* need more */
1613 memcpy(&s5_req, p, sizeof(s5_req));
1614 if (s5_req.version != 0x05 ||
1615 s5_req.command != SSH_SOCKS5_CONNECT ||
1616 s5_req.reserved != 0x00) {
1617 debug2("channel %d: only socks5 connect supported", c->self);
1618 return -1;
1619 }
1620 switch (s5_req.atyp){
1621 case SSH_SOCKS5_IPV4:
1622 addrlen = 4;
1623 af = AF_INET;
1624 break;
1625 case SSH_SOCKS5_DOMAIN:
1626 addrlen = p[sizeof(s5_req)];
1627 af = -1;
1628 break;
1629 case SSH_SOCKS5_IPV6:
1630 addrlen = 16;
1631 af = AF_INET6;
1632 break;
1633 default:
1634 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp);
1635 return -1;
1636 }
1637 need = sizeof(s5_req) + addrlen + 2;
1638 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1639 need++;
1640 if (have < need)
1641 return 0;
1642 if ((r = sshbuf_consume(input, sizeof(s5_req))) != 0)
1643 fatal_fr(r, "channel %d: consume", c->self);
1644 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) {
1645 /* host string length */
1646 if ((r = sshbuf_consume(input, 1)) != 0)
1647 fatal_fr(r, "channel %d: consume", c->self);
1648 }
1649 if ((r = sshbuf_get(input, &dest_addr, addrlen)) != 0 ||
1650 (r = sshbuf_get(input, &dest_port, 2)) != 0) {
1651 debug_r(r, "channel %d: parse addr/port", c->self);
1652 return -1;
1653 }
1654 dest_addr[addrlen] = '\0';
1655 free(c->path);
1656 c->path = NULL;
1657 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) {
1658 if (addrlen >= NI_MAXHOST) {
1659 error("channel %d: dynamic request: socks5 hostname "
1660 "\"%.100s\" too long", c->self, dest_addr);
1661 return -1;
1662 }
1663 c->path = xstrdup(dest_addr);
1664 } else {
1665 if (inet_ntop(af, dest_addr, ntop, sizeof(ntop)) == NULL)
1666 return -1;
1667 c->path = xstrdup(ntop);
1668 }
1669 c->host_port = ntohs(dest_port);
1670
1671 debug2("channel %d: dynamic request: socks5 host %s port %u command %u",
1672 c->self, c->path, c->host_port, s5_req.command);
1673
1674 s5_rsp.version = 0x05;
1675 s5_rsp.command = SSH_SOCKS5_SUCCESS;
1676 s5_rsp.reserved = 0; /* ignored */
1677 s5_rsp.atyp = SSH_SOCKS5_IPV4;
1678 dest_port = 0; /* ignored */
1679
1680 if ((r = sshbuf_put(output, &s5_rsp, sizeof(s5_rsp))) != 0 ||
1681 (r = sshbuf_put_u32(output, ntohl(INADDR_ANY))) != 0 ||
1682 (r = sshbuf_put(output, &dest_port, sizeof(dest_port))) != 0)
1683 fatal_fr(r, "channel %d: append reply", c->self);
1684 return 1;
1685 }
1686
1687 Channel *
channel_connect_stdio_fwd(struct ssh * ssh,const char * host_to_connect,int port_to_connect,int in,int out,int nonblock)1688 channel_connect_stdio_fwd(struct ssh *ssh,
1689 const char *host_to_connect, int port_to_connect,
1690 int in, int out, int nonblock)
1691 {
1692 Channel *c;
1693
1694 debug_f("%s:%d", host_to_connect, port_to_connect);
1695
1696 c = channel_new(ssh, "stdio-forward", SSH_CHANNEL_OPENING, in, out,
1697 -1, CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
1698 0, "stdio-forward", nonblock);
1699
1700 c->path = xstrdup(host_to_connect);
1701 c->host_port = port_to_connect;
1702 c->listening_port = 0;
1703 c->force_drain = 1;
1704
1705 channel_register_fds(ssh, c, in, out, -1, 0, 1, 0);
1706 port_open_helper(ssh, c, port_to_connect == PORT_STREAMLOCAL ?
1707 "direct-streamlocal@openssh.com" : "direct-tcpip");
1708
1709 return c;
1710 }
1711
1712 /* dynamic port forwarding */
1713 static void
channel_pre_dynamic(struct ssh * ssh,Channel * c)1714 channel_pre_dynamic(struct ssh *ssh, Channel *c)
1715 {
1716 const u_char *p;
1717 u_int have;
1718 int ret;
1719
1720 c->io_want = 0;
1721 have = sshbuf_len(c->input);
1722 debug2("channel %d: pre_dynamic: have %d", c->self, have);
1723 /* sshbuf_dump(c->input, stderr); */
1724 /* check if the fixed size part of the packet is in buffer. */
1725 if (have < 3) {
1726 /* need more */
1727 c->io_want |= SSH_CHAN_IO_RFD;
1728 return;
1729 }
1730 /* try to guess the protocol */
1731 p = sshbuf_ptr(c->input);
1732 /* XXX sshbuf_peek_u8? */
1733 switch (p[0]) {
1734 case 0x04:
1735 ret = channel_decode_socks4(c, c->input, c->output);
1736 break;
1737 case 0x05:
1738 ret = channel_decode_socks5(c, c->input, c->output);
1739 break;
1740 default:
1741 ret = -1;
1742 break;
1743 }
1744 if (ret < 0) {
1745 chan_mark_dead(ssh, c);
1746 } else if (ret == 0) {
1747 debug2("channel %d: pre_dynamic: need more", c->self);
1748 /* need more */
1749 c->io_want |= SSH_CHAN_IO_RFD;
1750 if (sshbuf_len(c->output))
1751 c->io_want |= SSH_CHAN_IO_WFD;
1752 } else {
1753 /* switch to the next state */
1754 c->type = SSH_CHANNEL_OPENING;
1755 port_open_helper(ssh, c, "direct-tcpip");
1756 }
1757 }
1758
1759 /* simulate read-error */
1760 static void
rdynamic_close(struct ssh * ssh,Channel * c)1761 rdynamic_close(struct ssh *ssh, Channel *c)
1762 {
1763 c->type = SSH_CHANNEL_OPEN;
1764 channel_force_close(ssh, c, 0);
1765 }
1766
1767 /* reverse dynamic port forwarding */
1768 static void
channel_before_prepare_io_rdynamic(struct ssh * ssh,Channel * c)1769 channel_before_prepare_io_rdynamic(struct ssh *ssh, Channel *c)
1770 {
1771 const u_char *p;
1772 u_int have, len;
1773 int r, ret;
1774
1775 have = sshbuf_len(c->output);
1776 debug2("channel %d: pre_rdynamic: have %d", c->self, have);
1777 /* sshbuf_dump(c->output, stderr); */
1778 /* EOF received */
1779 if (c->flags & CHAN_EOF_RCVD) {
1780 if ((r = sshbuf_consume(c->output, have)) != 0)
1781 fatal_fr(r, "channel %d: consume", c->self);
1782 rdynamic_close(ssh, c);
1783 return;
1784 }
1785 /* check if the fixed size part of the packet is in buffer. */
1786 if (have < 3)
1787 return;
1788 /* try to guess the protocol */
1789 p = sshbuf_ptr(c->output);
1790 switch (p[0]) {
1791 case 0x04:
1792 /* switch input/output for reverse forwarding */
1793 ret = channel_decode_socks4(c, c->output, c->input);
1794 break;
1795 case 0x05:
1796 ret = channel_decode_socks5(c, c->output, c->input);
1797 break;
1798 default:
1799 ret = -1;
1800 break;
1801 }
1802 if (ret < 0) {
1803 rdynamic_close(ssh, c);
1804 } else if (ret == 0) {
1805 debug2("channel %d: pre_rdynamic: need more", c->self);
1806 /* send socks request to peer */
1807 len = sshbuf_len(c->input);
1808 if (len > 0 && len < c->remote_window) {
1809 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 ||
1810 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 ||
1811 (r = sshpkt_put_stringb(ssh, c->input)) != 0 ||
1812 (r = sshpkt_send(ssh)) != 0) {
1813 fatal_fr(r, "channel %i: rdynamic", c->self);
1814 }
1815 if ((r = sshbuf_consume(c->input, len)) != 0)
1816 fatal_fr(r, "channel %d: consume", c->self);
1817 c->remote_window -= len;
1818 }
1819 } else if (rdynamic_connect_finish(ssh, c) < 0) {
1820 /* the connect failed */
1821 rdynamic_close(ssh, c);
1822 }
1823 }
1824
1825 /* This is our fake X11 server socket. */
1826 static void
channel_post_x11_listener(struct ssh * ssh,Channel * c)1827 channel_post_x11_listener(struct ssh *ssh, Channel *c)
1828 {
1829 Channel *nc;
1830 struct sockaddr_storage addr;
1831 int r, newsock, oerrno, remote_port;
1832 socklen_t addrlen;
1833 char buf[16384], *remote_ipaddr;
1834
1835 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0)
1836 return;
1837
1838 debug("X11 connection requested.");
1839 addrlen = sizeof(addr);
1840 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1841 if (c->single_connection) {
1842 oerrno = errno;
1843 debug2("single_connection: closing X11 listener.");
1844 channel_close_fd(ssh, c, &c->sock);
1845 chan_mark_dead(ssh, c);
1846 errno = oerrno;
1847 }
1848 if (newsock == -1) {
1849 if (errno != EINTR && errno != EWOULDBLOCK &&
1850 errno != ECONNABORTED)
1851 error("accept: %.100s", strerror(errno));
1852 if (errno == EMFILE || errno == ENFILE)
1853 c->notbefore = monotime() + 1;
1854 return;
1855 }
1856 set_nodelay(newsock);
1857 remote_ipaddr = get_peer_ipaddr(newsock);
1858 remote_port = get_peer_port(newsock);
1859 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1860 remote_ipaddr, remote_port);
1861
1862 nc = channel_new(ssh, "x11-connection",
1863 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1864 c->local_window_max, c->local_maxpacket, 0, buf, 1);
1865 open_preamble(ssh, __func__, nc, "x11");
1866 if ((r = sshpkt_put_cstring(ssh, remote_ipaddr)) != 0 ||
1867 (r = sshpkt_put_u32(ssh, remote_port)) != 0) {
1868 fatal_fr(r, "channel %i: reply", c->self);
1869 }
1870 if ((r = sshpkt_send(ssh)) != 0)
1871 fatal_fr(r, "channel %i: send", c->self);
1872 free(remote_ipaddr);
1873 }
1874
1875 static void
port_open_helper(struct ssh * ssh,Channel * c,char * rtype)1876 port_open_helper(struct ssh *ssh, Channel *c, char *rtype)
1877 {
1878 char *local_ipaddr = get_local_ipaddr(c->sock);
1879 int local_port = c->sock == -1 ? 65536 : get_local_port(c->sock);
1880 char *remote_ipaddr = get_peer_ipaddr(c->sock);
1881 int remote_port = get_peer_port(c->sock);
1882 int r;
1883
1884 if (remote_port == -1) {
1885 /* Fake addr/port to appease peers that validate it (Tectia) */
1886 free(remote_ipaddr);
1887 remote_ipaddr = xstrdup("127.0.0.1");
1888 remote_port = 65535;
1889 }
1890
1891 free(c->remote_name);
1892 xasprintf(&c->remote_name,
1893 "%s: listening port %d for %.100s port %d, "
1894 "connect from %.200s port %d to %.100s port %d",
1895 rtype, c->listening_port, c->path, c->host_port,
1896 remote_ipaddr, remote_port, local_ipaddr, local_port);
1897
1898 open_preamble(ssh, __func__, c, rtype);
1899 if (strcmp(rtype, "direct-tcpip") == 0) {
1900 /* target host, port */
1901 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0 ||
1902 (r = sshpkt_put_u32(ssh, c->host_port)) != 0)
1903 fatal_fr(r, "channel %i: reply", c->self);
1904 } else if (strcmp(rtype, "direct-streamlocal@openssh.com") == 0) {
1905 /* target path */
1906 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0)
1907 fatal_fr(r, "channel %i: reply", c->self);
1908 } else if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) {
1909 /* listen path */
1910 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0)
1911 fatal_fr(r, "channel %i: reply", c->self);
1912 } else {
1913 /* listen address, port */
1914 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0 ||
1915 (r = sshpkt_put_u32(ssh, local_port)) != 0)
1916 fatal_fr(r, "channel %i: reply", c->self);
1917 }
1918 if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) {
1919 /* reserved for future owner/mode info */
1920 if ((r = sshpkt_put_cstring(ssh, "")) != 0)
1921 fatal_fr(r, "channel %i: reply", c->self);
1922 } else {
1923 /* originator host and port */
1924 if ((r = sshpkt_put_cstring(ssh, remote_ipaddr)) != 0 ||
1925 (r = sshpkt_put_u32(ssh, (u_int)remote_port)) != 0)
1926 fatal_fr(r, "channel %i: reply", c->self);
1927 }
1928 if ((r = sshpkt_send(ssh)) != 0)
1929 fatal_fr(r, "channel %i: send", c->self);
1930 free(remote_ipaddr);
1931 free(local_ipaddr);
1932 }
1933
1934 void
channel_set_x11_refuse_time(struct ssh * ssh,time_t refuse_time)1935 channel_set_x11_refuse_time(struct ssh *ssh, time_t refuse_time)
1936 {
1937 ssh->chanctxt->x11_refuse_time = refuse_time;
1938 }
1939
1940 /*
1941 * This socket is listening for connections to a forwarded TCP/IP port.
1942 */
1943 static void
channel_post_port_listener(struct ssh * ssh,Channel * c)1944 channel_post_port_listener(struct ssh *ssh, Channel *c)
1945 {
1946 Channel *nc;
1947 struct sockaddr_storage addr;
1948 int newsock, nextstate;
1949 socklen_t addrlen;
1950 char *rtype;
1951
1952 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0)
1953 return;
1954
1955 debug("Connection to port %d forwarding to %.100s port %d requested.",
1956 c->listening_port, c->path, c->host_port);
1957
1958 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1959 nextstate = SSH_CHANNEL_OPENING;
1960 rtype = "forwarded-tcpip";
1961 } else if (c->type == SSH_CHANNEL_RUNIX_LISTENER) {
1962 nextstate = SSH_CHANNEL_OPENING;
1963 rtype = "forwarded-streamlocal@openssh.com";
1964 } else if (c->host_port == PORT_STREAMLOCAL) {
1965 nextstate = SSH_CHANNEL_OPENING;
1966 rtype = "direct-streamlocal@openssh.com";
1967 } else if (c->host_port == 0) {
1968 nextstate = SSH_CHANNEL_DYNAMIC;
1969 rtype = "dynamic-tcpip";
1970 } else {
1971 nextstate = SSH_CHANNEL_OPENING;
1972 rtype = "direct-tcpip";
1973 }
1974
1975 addrlen = sizeof(addr);
1976 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1977 if (newsock == -1) {
1978 if (errno != EINTR && errno != EWOULDBLOCK &&
1979 errno != ECONNABORTED)
1980 error("accept: %.100s", strerror(errno));
1981 if (errno == EMFILE || errno == ENFILE)
1982 c->notbefore = monotime() + 1;
1983 return;
1984 }
1985 if (c->host_port != PORT_STREAMLOCAL)
1986 set_nodelay(newsock);
1987 nc = channel_new(ssh, rtype, nextstate, newsock, newsock, -1,
1988 c->local_window_max, c->local_maxpacket, 0, rtype, 1);
1989 nc->listening_port = c->listening_port;
1990 nc->host_port = c->host_port;
1991 if (c->path != NULL)
1992 nc->path = xstrdup(c->path);
1993
1994 if (nextstate != SSH_CHANNEL_DYNAMIC)
1995 port_open_helper(ssh, nc, rtype);
1996 }
1997
1998 /*
1999 * This is the authentication agent socket listening for connections from
2000 * clients.
2001 */
2002 static void
channel_post_auth_listener(struct ssh * ssh,Channel * c)2003 channel_post_auth_listener(struct ssh *ssh, Channel *c)
2004 {
2005 Channel *nc;
2006 int r, newsock;
2007 struct sockaddr_storage addr;
2008 socklen_t addrlen;
2009
2010 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0)
2011 return;
2012
2013 addrlen = sizeof(addr);
2014 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
2015 if (newsock == -1) {
2016 error("accept from auth socket: %.100s", strerror(errno));
2017 if (errno == EMFILE || errno == ENFILE)
2018 c->notbefore = monotime() + 1;
2019 return;
2020 }
2021 nc = channel_new(ssh, "agent-connection",
2022 SSH_CHANNEL_OPENING, newsock, newsock, -1,
2023 c->local_window_max, c->local_maxpacket,
2024 0, "accepted auth socket", 1);
2025 open_preamble(ssh, __func__, nc, "auth-agent@openssh.com");
2026 if ((r = sshpkt_send(ssh)) != 0)
2027 fatal_fr(r, "channel %i", c->self);
2028 }
2029
2030 static void
channel_post_connecting(struct ssh * ssh,Channel * c)2031 channel_post_connecting(struct ssh *ssh, Channel *c)
2032 {
2033 int err = 0, sock, isopen, r;
2034 socklen_t sz = sizeof(err);
2035
2036 if ((c->io_ready & SSH_CHAN_IO_SOCK_W) == 0)
2037 return;
2038 if (!c->have_remote_id)
2039 fatal_f("channel %d: no remote id", c->self);
2040 /* for rdynamic the OPEN_CONFIRMATION has been sent already */
2041 isopen = (c->type == SSH_CHANNEL_RDYNAMIC_FINISH);
2042
2043 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) == -1) {
2044 err = errno;
2045 error("getsockopt SO_ERROR failed");
2046 }
2047
2048 if (err == 0) {
2049 /* Non-blocking connection completed */
2050 debug("channel %d: connected to %s port %d",
2051 c->self, c->connect_ctx.host, c->connect_ctx.port);
2052 channel_connect_ctx_free(&c->connect_ctx);
2053 c->type = SSH_CHANNEL_OPEN;
2054 channel_set_used_time(ssh, c);
2055 if (isopen) {
2056 /* no message necessary */
2057 } else {
2058 if ((r = sshpkt_start(ssh,
2059 SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 ||
2060 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 ||
2061 (r = sshpkt_put_u32(ssh, c->self)) != 0 ||
2062 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 ||
2063 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0 ||
2064 (r = sshpkt_send(ssh)) != 0)
2065 fatal_fr(r, "channel %i open confirm", c->self);
2066 }
2067 return;
2068 }
2069 if (err == EINTR || err == EAGAIN || err == EINPROGRESS)
2070 return;
2071
2072 /* Non-blocking connection failed */
2073 debug("channel %d: connection failed: %s", c->self, strerror(err));
2074
2075 /* Try next address, if any */
2076 if ((sock = connect_next(&c->connect_ctx)) == -1) {
2077 /* Exhausted all addresses for this destination */
2078 error("connect_to %.100s port %d: failed.",
2079 c->connect_ctx.host, c->connect_ctx.port);
2080 channel_connect_ctx_free(&c->connect_ctx);
2081 if (isopen) {
2082 rdynamic_close(ssh, c);
2083 } else {
2084 if ((r = sshpkt_start(ssh,
2085 SSH2_MSG_CHANNEL_OPEN_FAILURE)) != 0 ||
2086 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 ||
2087 (r = sshpkt_put_u32(ssh,
2088 SSH2_OPEN_CONNECT_FAILED)) != 0 ||
2089 (r = sshpkt_put_cstring(ssh, strerror(err))) != 0 ||
2090 (r = sshpkt_put_cstring(ssh, "")) != 0 ||
2091 (r = sshpkt_send(ssh)) != 0)
2092 fatal_fr(r, "channel %i: failure", c->self);
2093 chan_mark_dead(ssh, c);
2094 }
2095 }
2096
2097 /* New non-blocking connection in progress */
2098 close(c->sock);
2099 c->sock = c->rfd = c->wfd = sock;
2100 }
2101
2102 static int
channel_handle_rfd(struct ssh * ssh,Channel * c)2103 channel_handle_rfd(struct ssh *ssh, Channel *c)
2104 {
2105 char buf[CHAN_RBUF];
2106 ssize_t len;
2107 int r, force;
2108 size_t nr = 0, have, avail, maxlen = CHANNEL_MAX_READ;
2109 int pty_zeroread = 0;
2110
2111 #ifdef PTY_ZEROREAD
2112 /* Bug on AIX: read(1) can return 0 for a non-closed fd */
2113 pty_zeroread = c->isatty;
2114 #endif
2115
2116 force = c->isatty && c->detach_close && c->istate != CHAN_INPUT_CLOSED;
2117
2118 if (!force && (c->io_ready & SSH_CHAN_IO_RFD) == 0)
2119 return 1;
2120 if ((avail = sshbuf_avail(c->input)) == 0)
2121 return 1; /* Shouldn't happen */
2122
2123 /*
2124 * For "simple" channels (i.e. not datagram or filtered), we can
2125 * read directly to the channel buffer.
2126 */
2127 if (!pty_zeroread && c->input_filter == NULL && !c->datagram) {
2128 /* Only OPEN channels have valid rwin */
2129 if (c->type == SSH_CHANNEL_OPEN) {
2130 if ((have = sshbuf_len(c->input)) >= c->remote_window)
2131 return 1; /* shouldn't happen */
2132 if (maxlen > c->remote_window - have)
2133 maxlen = c->remote_window - have;
2134 }
2135 if (maxlen > avail)
2136 maxlen = avail;
2137 if ((r = sshbuf_read(c->rfd, c->input, maxlen, &nr)) != 0) {
2138 if (errno == EINTR || (!force &&
2139 (errno == EAGAIN || errno == EWOULDBLOCK)))
2140 return 1;
2141 debug2("channel %d: read failed rfd %d maxlen %zu: %s",
2142 c->self, c->rfd, maxlen, ssh_err(r));
2143 goto rfail;
2144 }
2145 if (nr != 0)
2146 channel_set_used_time(ssh, c);
2147 return 1;
2148 }
2149
2150 errno = 0;
2151 len = read(c->rfd, buf, sizeof(buf));
2152 /* fixup AIX zero-length read with errno set to look more like errors */
2153 if (pty_zeroread && len == 0 && errno != 0)
2154 len = -1;
2155 if (len == -1 && (errno == EINTR ||
2156 ((errno == EAGAIN || errno == EWOULDBLOCK) && !force)))
2157 return 1;
2158 if (len < 0 || (!pty_zeroread && len == 0)) {
2159 debug2("channel %d: read<=0 rfd %d len %zd: %s",
2160 c->self, c->rfd, len,
2161 len == 0 ? "closed" : strerror(errno));
2162 rfail:
2163 if (c->type != SSH_CHANNEL_OPEN) {
2164 debug2("channel %d: not open", c->self);
2165 chan_mark_dead(ssh, c);
2166 return -1;
2167 } else {
2168 chan_read_failed(ssh, c);
2169 }
2170 return -1;
2171 }
2172 channel_set_used_time(ssh, c);
2173 if (c->input_filter != NULL) {
2174 if (c->input_filter(ssh, c, buf, len) == -1) {
2175 debug2("channel %d: filter stops", c->self);
2176 chan_read_failed(ssh, c);
2177 }
2178 } else if (c->datagram) {
2179 if ((r = sshbuf_put_string(c->input, buf, len)) != 0)
2180 fatal_fr(r, "channel %i: put datagram", c->self);
2181 } else if ((r = sshbuf_put(c->input, buf, len)) != 0)
2182 fatal_fr(r, "channel %i: put data", c->self);
2183
2184 return 1;
2185 }
2186
2187 static int
channel_handle_wfd(struct ssh * ssh,Channel * c)2188 channel_handle_wfd(struct ssh *ssh, Channel *c)
2189 {
2190 struct termios tio;
2191 u_char *data = NULL, *buf; /* XXX const; need filter API change */
2192 size_t dlen, olen = 0;
2193 int r, len;
2194
2195 if ((c->io_ready & SSH_CHAN_IO_WFD) == 0)
2196 return 1;
2197 if (sshbuf_len(c->output) == 0)
2198 return 1;
2199
2200 /* Send buffered output data to the socket. */
2201 olen = sshbuf_len(c->output);
2202 if (c->output_filter != NULL) {
2203 if ((buf = c->output_filter(ssh, c, &data, &dlen)) == NULL) {
2204 debug2("channel %d: filter stops", c->self);
2205 if (c->type != SSH_CHANNEL_OPEN)
2206 chan_mark_dead(ssh, c);
2207 else
2208 chan_write_failed(ssh, c);
2209 return -1;
2210 }
2211 } else if (c->datagram) {
2212 if ((r = sshbuf_get_string(c->output, &data, &dlen)) != 0)
2213 fatal_fr(r, "channel %i: get datagram", c->self);
2214 buf = data;
2215 } else {
2216 buf = data = sshbuf_mutable_ptr(c->output);
2217 dlen = sshbuf_len(c->output);
2218 }
2219
2220 if (c->datagram) {
2221 /* ignore truncated writes, datagrams might get lost */
2222 len = write(c->wfd, buf, dlen);
2223 free(data);
2224 if (len == -1 && (errno == EINTR || errno == EAGAIN ||
2225 errno == EWOULDBLOCK))
2226 return 1;
2227 if (len <= 0)
2228 goto write_fail;
2229 goto out;
2230 }
2231
2232 #ifdef _AIX
2233 /* XXX: Later AIX versions can't push as much data to tty */
2234 if (c->wfd_isatty)
2235 dlen = MINIMUM(dlen, 8*1024);
2236 #endif
2237
2238 len = write(c->wfd, buf, dlen);
2239 if (len == -1 &&
2240 (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK))
2241 return 1;
2242 if (len <= 0) {
2243 write_fail:
2244 if (c->type != SSH_CHANNEL_OPEN) {
2245 debug2("channel %d: not open", c->self);
2246 chan_mark_dead(ssh, c);
2247 return -1;
2248 } else {
2249 chan_write_failed(ssh, c);
2250 }
2251 return -1;
2252 }
2253 channel_set_used_time(ssh, c);
2254 #ifndef BROKEN_TCGETATTR_ICANON
2255 if (c->isatty && dlen >= 1 && buf[0] != '\r') {
2256 if (tcgetattr(c->wfd, &tio) == 0 &&
2257 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
2258 /*
2259 * Simulate echo to reduce the impact of
2260 * traffic analysis. We need to match the
2261 * size of a SSH2_MSG_CHANNEL_DATA message
2262 * (4 byte channel id + buf)
2263 */
2264 if ((r = sshpkt_msg_ignore(ssh, 4+len)) != 0 ||
2265 (r = sshpkt_send(ssh)) != 0)
2266 fatal_fr(r, "channel %i: ignore", c->self);
2267 }
2268 }
2269 #endif /* BROKEN_TCGETATTR_ICANON */
2270 if ((r = sshbuf_consume(c->output, len)) != 0)
2271 fatal_fr(r, "channel %i: consume", c->self);
2272 out:
2273 c->local_consumed += olen - sshbuf_len(c->output);
2274
2275 return 1;
2276 }
2277
2278 static int
channel_handle_efd_write(struct ssh * ssh,Channel * c)2279 channel_handle_efd_write(struct ssh *ssh, Channel *c)
2280 {
2281 int r;
2282 ssize_t len;
2283
2284 if ((c->io_ready & SSH_CHAN_IO_EFD_W) == 0)
2285 return 1;
2286 if (sshbuf_len(c->extended) == 0)
2287 return 1;
2288
2289 len = write(c->efd, sshbuf_ptr(c->extended),
2290 sshbuf_len(c->extended));
2291 debug2("channel %d: written %zd to efd %d", c->self, len, c->efd);
2292 if (len == -1 && (errno == EINTR || errno == EAGAIN ||
2293 errno == EWOULDBLOCK))
2294 return 1;
2295 if (len <= 0) {
2296 debug2("channel %d: closing write-efd %d", c->self, c->efd);
2297 channel_close_fd(ssh, c, &c->efd);
2298 } else {
2299 if ((r = sshbuf_consume(c->extended, len)) != 0)
2300 fatal_fr(r, "channel %i: consume", c->self);
2301 c->local_consumed += len;
2302 channel_set_used_time(ssh, c);
2303 }
2304 return 1;
2305 }
2306
2307 static int
channel_handle_efd_read(struct ssh * ssh,Channel * c)2308 channel_handle_efd_read(struct ssh *ssh, Channel *c)
2309 {
2310 char buf[CHAN_RBUF];
2311 ssize_t len;
2312 int r, force;
2313
2314 force = c->isatty && c->detach_close && c->istate != CHAN_INPUT_CLOSED;
2315
2316 if (!force && (c->io_ready & SSH_CHAN_IO_EFD_R) == 0)
2317 return 1;
2318
2319 len = read(c->efd, buf, sizeof(buf));
2320 debug2("channel %d: read %zd from efd %d", c->self, len, c->efd);
2321 if (len == -1 && (errno == EINTR || ((errno == EAGAIN ||
2322 errno == EWOULDBLOCK) && !force)))
2323 return 1;
2324 if (len <= 0) {
2325 debug2("channel %d: closing read-efd %d", c->self, c->efd);
2326 channel_close_fd(ssh, c, &c->efd);
2327 return 1;
2328 }
2329 channel_set_used_time(ssh, c);
2330 if (c->extended_usage == CHAN_EXTENDED_IGNORE)
2331 debug3("channel %d: discard efd", c->self);
2332 else if ((r = sshbuf_put(c->extended, buf, len)) != 0)
2333 fatal_fr(r, "channel %i: append", c->self);
2334 return 1;
2335 }
2336
2337 static int
channel_handle_efd(struct ssh * ssh,Channel * c)2338 channel_handle_efd(struct ssh *ssh, Channel *c)
2339 {
2340 if (c->efd == -1)
2341 return 1;
2342
2343 /** XXX handle drain efd, too */
2344
2345 if (c->extended_usage == CHAN_EXTENDED_WRITE)
2346 return channel_handle_efd_write(ssh, c);
2347 else if (c->extended_usage == CHAN_EXTENDED_READ ||
2348 c->extended_usage == CHAN_EXTENDED_IGNORE)
2349 return channel_handle_efd_read(ssh, c);
2350
2351 return 1;
2352 }
2353
2354 static int
channel_check_window(struct ssh * ssh,Channel * c)2355 channel_check_window(struct ssh *ssh, Channel *c)
2356 {
2357 int r;
2358
2359 if (c->type == SSH_CHANNEL_OPEN &&
2360 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
2361 ((c->local_window_max - c->local_window >
2362 c->local_maxpacket*3) ||
2363 c->local_window < c->local_window_max/2) &&
2364 c->local_consumed > 0) {
2365 if (!c->have_remote_id)
2366 fatal_f("channel %d: no remote id", c->self);
2367 if ((r = sshpkt_start(ssh,
2368 SSH2_MSG_CHANNEL_WINDOW_ADJUST)) != 0 ||
2369 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 ||
2370 (r = sshpkt_put_u32(ssh, c->local_consumed)) != 0 ||
2371 (r = sshpkt_send(ssh)) != 0) {
2372 fatal_fr(r, "channel %i", c->self);
2373 }
2374 debug2("channel %d: window %d sent adjust %d", c->self,
2375 c->local_window, c->local_consumed);
2376 c->local_window += c->local_consumed;
2377 c->local_consumed = 0;
2378 }
2379 return 1;
2380 }
2381
2382 static void
channel_post_open(struct ssh * ssh,Channel * c)2383 channel_post_open(struct ssh *ssh, Channel *c)
2384 {
2385 channel_handle_rfd(ssh, c);
2386 channel_handle_wfd(ssh, c);
2387 channel_handle_efd(ssh, c);
2388 channel_check_window(ssh, c);
2389 }
2390
2391 static u_int
read_mux(struct ssh * ssh,Channel * c,u_int need)2392 read_mux(struct ssh *ssh, Channel *c, u_int need)
2393 {
2394 char buf[CHAN_RBUF];
2395 ssize_t len;
2396 u_int rlen;
2397 int r;
2398
2399 if (sshbuf_len(c->input) < need) {
2400 rlen = need - sshbuf_len(c->input);
2401 len = read(c->rfd, buf, MINIMUM(rlen, CHAN_RBUF));
2402 if (len == -1 && (errno == EINTR || errno == EAGAIN))
2403 return sshbuf_len(c->input);
2404 if (len <= 0) {
2405 debug2("channel %d: ctl read<=0 rfd %d len %zd",
2406 c->self, c->rfd, len);
2407 chan_read_failed(ssh, c);
2408 return 0;
2409 } else if ((r = sshbuf_put(c->input, buf, len)) != 0)
2410 fatal_fr(r, "channel %i: append", c->self);
2411 }
2412 return sshbuf_len(c->input);
2413 }
2414
2415 static void
channel_post_mux_client_read(struct ssh * ssh,Channel * c)2416 channel_post_mux_client_read(struct ssh *ssh, Channel *c)
2417 {
2418 u_int need;
2419
2420 if ((c->io_ready & SSH_CHAN_IO_RFD) == 0)
2421 return;
2422 if (c->istate != CHAN_INPUT_OPEN && c->istate != CHAN_INPUT_WAIT_DRAIN)
2423 return;
2424 if (c->mux_pause)
2425 return;
2426
2427 /*
2428 * Don't not read past the precise end of packets to
2429 * avoid disrupting fd passing.
2430 */
2431 if (read_mux(ssh, c, 4) < 4) /* read header */
2432 return;
2433 /* XXX sshbuf_peek_u32 */
2434 need = PEEK_U32(sshbuf_ptr(c->input));
2435 #define CHANNEL_MUX_MAX_PACKET (256 * 1024)
2436 if (need > CHANNEL_MUX_MAX_PACKET) {
2437 debug2("channel %d: packet too big %u > %u",
2438 c->self, CHANNEL_MUX_MAX_PACKET, need);
2439 chan_rcvd_oclose(ssh, c);
2440 return;
2441 }
2442 if (read_mux(ssh, c, need + 4) < need + 4) /* read body */
2443 return;
2444 if (c->mux_rcb(ssh, c) != 0) {
2445 debug("channel %d: mux_rcb failed", c->self);
2446 chan_mark_dead(ssh, c);
2447 return;
2448 }
2449 }
2450
2451 static void
channel_post_mux_client_write(struct ssh * ssh,Channel * c)2452 channel_post_mux_client_write(struct ssh *ssh, Channel *c)
2453 {
2454 ssize_t len;
2455 int r;
2456
2457 if ((c->io_ready & SSH_CHAN_IO_WFD) == 0)
2458 return;
2459 if (sshbuf_len(c->output) == 0)
2460 return;
2461
2462 len = write(c->wfd, sshbuf_ptr(c->output), sshbuf_len(c->output));
2463 if (len == -1 && (errno == EINTR || errno == EAGAIN))
2464 return;
2465 if (len <= 0) {
2466 chan_mark_dead(ssh, c);
2467 return;
2468 }
2469 if ((r = sshbuf_consume(c->output, len)) != 0)
2470 fatal_fr(r, "channel %i: consume", c->self);
2471 }
2472
2473 static void
channel_post_mux_client(struct ssh * ssh,Channel * c)2474 channel_post_mux_client(struct ssh *ssh, Channel *c)
2475 {
2476 channel_post_mux_client_read(ssh, c);
2477 channel_post_mux_client_write(ssh, c);
2478 }
2479
2480 static void
channel_post_mux_listener(struct ssh * ssh,Channel * c)2481 channel_post_mux_listener(struct ssh *ssh, Channel *c)
2482 {
2483 Channel *nc;
2484 struct sockaddr_storage addr;
2485 socklen_t addrlen;
2486 int newsock;
2487 uid_t euid;
2488 gid_t egid;
2489
2490 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0)
2491 return;
2492
2493 debug("multiplexing control connection");
2494
2495 /*
2496 * Accept connection on control socket
2497 */
2498 memset(&addr, 0, sizeof(addr));
2499 addrlen = sizeof(addr);
2500 if ((newsock = accept(c->sock, (struct sockaddr*)&addr,
2501 &addrlen)) == -1) {
2502 error_f("accept: %s", strerror(errno));
2503 if (errno == EMFILE || errno == ENFILE)
2504 c->notbefore = monotime() + 1;
2505 return;
2506 }
2507
2508 if (getpeereid(newsock, &euid, &egid) == -1) {
2509 error_f("getpeereid failed: %s", strerror(errno));
2510 close(newsock);
2511 return;
2512 }
2513 if ((euid != 0) && (getuid() != euid)) {
2514 error("multiplex uid mismatch: peer euid %u != uid %u",
2515 (u_int)euid, (u_int)getuid());
2516 close(newsock);
2517 return;
2518 }
2519 nc = channel_new(ssh, "mux-control", SSH_CHANNEL_MUX_CLIENT,
2520 newsock, newsock, -1, c->local_window_max,
2521 c->local_maxpacket, 0, "mux-control", 1);
2522 nc->mux_rcb = c->mux_rcb;
2523 debug3_f("new mux channel %d fd %d", nc->self, nc->sock);
2524 /* establish state */
2525 nc->mux_rcb(ssh, nc);
2526 /* mux state transitions must not elicit protocol messages */
2527 nc->flags |= CHAN_LOCAL;
2528 }
2529
2530 static void
channel_handler_init(struct ssh_channels * sc)2531 channel_handler_init(struct ssh_channels *sc)
2532 {
2533 chan_fn **pre, **post;
2534
2535 if ((pre = calloc(SSH_CHANNEL_MAX_TYPE, sizeof(*pre))) == NULL ||
2536 (post = calloc(SSH_CHANNEL_MAX_TYPE, sizeof(*post))) == NULL)
2537 fatal_f("allocation failed");
2538
2539 pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
2540 pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
2541 pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
2542 pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
2543 pre[SSH_CHANNEL_UNIX_LISTENER] = &channel_pre_listener;
2544 pre[SSH_CHANNEL_RUNIX_LISTENER] = &channel_pre_listener;
2545 pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
2546 pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
2547 pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
2548 pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
2549 pre[SSH_CHANNEL_RDYNAMIC_FINISH] = &channel_pre_connecting;
2550 pre[SSH_CHANNEL_MUX_LISTENER] = &channel_pre_listener;
2551 pre[SSH_CHANNEL_MUX_CLIENT] = &channel_pre_mux_client;
2552
2553 post[SSH_CHANNEL_OPEN] = &channel_post_open;
2554 post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
2555 post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
2556 post[SSH_CHANNEL_UNIX_LISTENER] = &channel_post_port_listener;
2557 post[SSH_CHANNEL_RUNIX_LISTENER] = &channel_post_port_listener;
2558 post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
2559 post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
2560 post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
2561 post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
2562 post[SSH_CHANNEL_RDYNAMIC_FINISH] = &channel_post_connecting;
2563 post[SSH_CHANNEL_MUX_LISTENER] = &channel_post_mux_listener;
2564 post[SSH_CHANNEL_MUX_CLIENT] = &channel_post_mux_client;
2565
2566 sc->channel_pre = pre;
2567 sc->channel_post = post;
2568 }
2569
2570 /* gc dead channels */
2571 static void
channel_garbage_collect(struct ssh * ssh,Channel * c)2572 channel_garbage_collect(struct ssh *ssh, Channel *c)
2573 {
2574 if (c == NULL)
2575 return;
2576 if (c->detach_user != NULL) {
2577 if (!chan_is_dead(ssh, c, c->detach_close))
2578 return;
2579
2580 debug2("channel %d: gc: notify user", c->self);
2581 c->detach_user(ssh, c->self, 0, NULL);
2582 /* if we still have a callback */
2583 if (c->detach_user != NULL)
2584 return;
2585 debug2("channel %d: gc: user detached", c->self);
2586 }
2587 if (!chan_is_dead(ssh, c, 1))
2588 return;
2589 debug2("channel %d: garbage collecting", c->self);
2590 channel_free(ssh, c);
2591 }
2592
2593 enum channel_table { CHAN_PRE, CHAN_POST };
2594
2595 static void
channel_handler(struct ssh * ssh,int table,struct timespec * timeout)2596 channel_handler(struct ssh *ssh, int table, struct timespec *timeout)
2597 {
2598 struct ssh_channels *sc = ssh->chanctxt;
2599 chan_fn **ftab = table == CHAN_PRE ? sc->channel_pre : sc->channel_post;
2600 u_int i, oalloc;
2601 Channel *c;
2602 time_t now;
2603
2604 now = monotime();
2605 for (i = 0, oalloc = sc->channels_alloc; i < oalloc; i++) {
2606 c = sc->channels[i];
2607 if (c == NULL)
2608 continue;
2609 /* Try to keep IO going while rekeying */
2610 if (ssh_packet_is_rekeying(ssh) && c->type != SSH_CHANNEL_OPEN)
2611 continue;
2612 if (c->delayed) {
2613 if (table == CHAN_PRE)
2614 c->delayed = 0;
2615 else
2616 continue;
2617 }
2618 if (ftab[c->type] != NULL) {
2619 if (table == CHAN_PRE && c->type == SSH_CHANNEL_OPEN &&
2620 channel_get_expiry(ssh, c) != 0 &&
2621 now >= channel_get_expiry(ssh, c)) {
2622 /* channel closed for inactivity */
2623 verbose("channel %d: closing after %u seconds "
2624 "of inactivity", c->self,
2625 c->inactive_deadline);
2626 channel_force_close(ssh, c, 1);
2627 } else if (c->notbefore <= now) {
2628 /* Run handlers that are not paused. */
2629 (*ftab[c->type])(ssh, c);
2630 /* inactivity timeouts must interrupt poll() */
2631 if (timeout != NULL &&
2632 c->type == SSH_CHANNEL_OPEN &&
2633 channel_get_expiry(ssh, c) != 0) {
2634 ptimeout_deadline_monotime(timeout,
2635 channel_get_expiry(ssh, c));
2636 }
2637 } else if (timeout != NULL) {
2638 /*
2639 * Arrange for poll() wakeup when channel pause
2640 * timer expires.
2641 */
2642 ptimeout_deadline_monotime(timeout,
2643 c->notbefore);
2644 }
2645 }
2646 channel_garbage_collect(ssh, c);
2647 }
2648 }
2649
2650 /*
2651 * Create sockets before preparing IO.
2652 * This is necessary for things that need to happen after reading
2653 * the network-input but need to be completed before IO event setup, e.g.
2654 * because they may create new channels.
2655 */
2656 static void
channel_before_prepare_io(struct ssh * ssh)2657 channel_before_prepare_io(struct ssh *ssh)
2658 {
2659 struct ssh_channels *sc = ssh->chanctxt;
2660 Channel *c;
2661 u_int i, oalloc;
2662
2663 for (i = 0, oalloc = sc->channels_alloc; i < oalloc; i++) {
2664 c = sc->channels[i];
2665 if (c == NULL)
2666 continue;
2667 if (c->type == SSH_CHANNEL_RDYNAMIC_OPEN)
2668 channel_before_prepare_io_rdynamic(ssh, c);
2669 }
2670 }
2671
2672 static void
dump_channel_poll(const char * func,const char * what,Channel * c,u_int pollfd_offset,struct pollfd * pfd)2673 dump_channel_poll(const char *func, const char *what, Channel *c,
2674 u_int pollfd_offset, struct pollfd *pfd)
2675 {
2676 #ifdef DEBUG_CHANNEL_POLL
2677 debug3("%s: channel %d: %s r%d w%d e%d s%d c->pfds [ %d %d %d %d ] "
2678 "io_want 0x%02x io_ready 0x%02x pfd[%u].fd=%d "
2679 "pfd.ev 0x%02x pfd.rev 0x%02x", func, c->self, what,
2680 c->rfd, c->wfd, c->efd, c->sock,
2681 c->pfds[0], c->pfds[1], c->pfds[2], c->pfds[3],
2682 c->io_want, c->io_ready,
2683 pollfd_offset, pfd->fd, pfd->events, pfd->revents);
2684 #endif
2685 }
2686
2687 /* Prepare pollfd entries for a single channel */
2688 static void
channel_prepare_pollfd(Channel * c,u_int * next_pollfd,struct pollfd * pfd,u_int npfd)2689 channel_prepare_pollfd(Channel *c, u_int *next_pollfd,
2690 struct pollfd *pfd, u_int npfd)
2691 {
2692 u_int ev, p = *next_pollfd;
2693
2694 if (c == NULL)
2695 return;
2696 if (p + 4 > npfd) {
2697 /* Shouldn't happen */
2698 fatal_f("channel %d: bad pfd offset %u (max %u)",
2699 c->self, p, npfd);
2700 }
2701 c->pfds[0] = c->pfds[1] = c->pfds[2] = c->pfds[3] = -1;
2702 /*
2703 * prepare c->rfd
2704 *
2705 * This is a special case, since c->rfd might be the same as
2706 * c->wfd, c->efd and/or c->sock. Handle those here if they want
2707 * IO too.
2708 */
2709 if (c->rfd != -1) {
2710 ev = 0;
2711 if ((c->io_want & SSH_CHAN_IO_RFD) != 0)
2712 ev |= POLLIN;
2713 /* rfd == wfd */
2714 if (c->wfd == c->rfd) {
2715 if ((c->io_want & SSH_CHAN_IO_WFD) != 0)
2716 ev |= POLLOUT;
2717 }
2718 /* rfd == efd */
2719 if (c->efd == c->rfd) {
2720 if ((c->io_want & SSH_CHAN_IO_EFD_R) != 0)
2721 ev |= POLLIN;
2722 if ((c->io_want & SSH_CHAN_IO_EFD_W) != 0)
2723 ev |= POLLOUT;
2724 }
2725 /* rfd == sock */
2726 if (c->sock == c->rfd) {
2727 if ((c->io_want & SSH_CHAN_IO_SOCK_R) != 0)
2728 ev |= POLLIN;
2729 if ((c->io_want & SSH_CHAN_IO_SOCK_W) != 0)
2730 ev |= POLLOUT;
2731 }
2732 /* Pack a pfd entry if any event armed for this fd */
2733 if (ev != 0) {
2734 c->pfds[0] = p;
2735 pfd[p].fd = c->rfd;
2736 pfd[p].events = ev;
2737 dump_channel_poll(__func__, "rfd", c, p, &pfd[p]);
2738 p++;
2739 }
2740 }
2741 /* prepare c->wfd if wanting IO and not already handled above */
2742 if (c->wfd != -1 && c->rfd != c->wfd) {
2743 ev = 0;
2744 if ((c->io_want & SSH_CHAN_IO_WFD))
2745 ev |= POLLOUT;
2746 /* Pack a pfd entry if any event armed for this fd */
2747 if (ev != 0) {
2748 c->pfds[1] = p;
2749 pfd[p].fd = c->wfd;
2750 pfd[p].events = ev;
2751 dump_channel_poll(__func__, "wfd", c, p, &pfd[p]);
2752 p++;
2753 }
2754 }
2755 /* prepare c->efd if wanting IO and not already handled above */
2756 if (c->efd != -1 && c->rfd != c->efd) {
2757 ev = 0;
2758 if ((c->io_want & SSH_CHAN_IO_EFD_R) != 0)
2759 ev |= POLLIN;
2760 if ((c->io_want & SSH_CHAN_IO_EFD_W) != 0)
2761 ev |= POLLOUT;
2762 /* Pack a pfd entry if any event armed for this fd */
2763 if (ev != 0) {
2764 c->pfds[2] = p;
2765 pfd[p].fd = c->efd;
2766 pfd[p].events = ev;
2767 dump_channel_poll(__func__, "efd", c, p, &pfd[p]);
2768 p++;
2769 }
2770 }
2771 /* prepare c->sock if wanting IO and not already handled above */
2772 if (c->sock != -1 && c->rfd != c->sock) {
2773 ev = 0;
2774 if ((c->io_want & SSH_CHAN_IO_SOCK_R) != 0)
2775 ev |= POLLIN;
2776 if ((c->io_want & SSH_CHAN_IO_SOCK_W) != 0)
2777 ev |= POLLOUT;
2778 /* Pack a pfd entry if any event armed for this fd */
2779 if (ev != 0) {
2780 c->pfds[3] = p;
2781 pfd[p].fd = c->sock;
2782 pfd[p].events = 0;
2783 dump_channel_poll(__func__, "sock", c, p, &pfd[p]);
2784 p++;
2785 }
2786 }
2787 *next_pollfd = p;
2788 }
2789
2790 /* * Allocate/prepare poll structure */
2791 void
channel_prepare_poll(struct ssh * ssh,struct pollfd ** pfdp,u_int * npfd_allocp,u_int * npfd_activep,u_int npfd_reserved,struct timespec * timeout)2792 channel_prepare_poll(struct ssh *ssh, struct pollfd **pfdp, u_int *npfd_allocp,
2793 u_int *npfd_activep, u_int npfd_reserved, struct timespec *timeout)
2794 {
2795 struct ssh_channels *sc = ssh->chanctxt;
2796 u_int i, oalloc, p, npfd = npfd_reserved;
2797
2798 channel_before_prepare_io(ssh); /* might create a new channel */
2799 /* clear out I/O flags from last poll */
2800 for (i = 0; i < sc->channels_alloc; i++) {
2801 if (sc->channels[i] == NULL)
2802 continue;
2803 sc->channels[i]->io_want = sc->channels[i]->io_ready = 0;
2804 }
2805 /* Allocate 4x pollfd for each channel (rfd, wfd, efd, sock) */
2806 if (sc->channels_alloc >= (INT_MAX / 4) - npfd_reserved)
2807 fatal_f("too many channels"); /* shouldn't happen */
2808 npfd += sc->channels_alloc * 4;
2809 if (npfd > *npfd_allocp) {
2810 *pfdp = xrecallocarray(*pfdp, *npfd_allocp,
2811 npfd, sizeof(**pfdp));
2812 *npfd_allocp = npfd;
2813 }
2814 *npfd_activep = npfd_reserved;
2815 oalloc = sc->channels_alloc;
2816
2817 channel_handler(ssh, CHAN_PRE, timeout);
2818
2819 if (oalloc != sc->channels_alloc) {
2820 /* shouldn't happen */
2821 fatal_f("channels_alloc changed during CHAN_PRE "
2822 "(was %u, now %u)", oalloc, sc->channels_alloc);
2823 }
2824
2825 /* Prepare pollfd */
2826 p = npfd_reserved;
2827 for (i = 0; i < sc->channels_alloc; i++)
2828 channel_prepare_pollfd(sc->channels[i], &p, *pfdp, npfd);
2829 *npfd_activep = p;
2830 }
2831
2832 static void
fd_ready(Channel * c,int p,struct pollfd * pfds,u_int npfd,int fd,const char * what,u_int revents_mask,u_int ready)2833 fd_ready(Channel *c, int p, struct pollfd *pfds, u_int npfd, int fd,
2834 const char *what, u_int revents_mask, u_int ready)
2835 {
2836 struct pollfd *pfd = &pfds[p];
2837
2838 if (fd == -1)
2839 return;
2840 if (p == -1 || (u_int)p >= npfd)
2841 fatal_f("channel %d: bad pfd %d (max %u)", c->self, p, npfd);
2842 dump_channel_poll(__func__, what, c, p, pfd);
2843 if (pfd->fd != fd) {
2844 fatal("channel %d: inconsistent %s fd=%d pollfd[%u].fd %d "
2845 "r%d w%d e%d s%d", c->self, what, fd, p, pfd->fd,
2846 c->rfd, c->wfd, c->efd, c->sock);
2847 }
2848 if ((pfd->revents & POLLNVAL) != 0) {
2849 fatal("channel %d: invalid %s pollfd[%u].fd %d r%d w%d e%d s%d",
2850 c->self, what, p, pfd->fd, c->rfd, c->wfd, c->efd, c->sock);
2851 }
2852 if ((pfd->revents & (revents_mask|POLLHUP|POLLERR)) != 0)
2853 c->io_ready |= ready & c->io_want;
2854 }
2855
2856 /*
2857 * After poll, perform any appropriate operations for channels which have
2858 * events pending.
2859 */
2860 void
channel_after_poll(struct ssh * ssh,struct pollfd * pfd,u_int npfd)2861 channel_after_poll(struct ssh *ssh, struct pollfd *pfd, u_int npfd)
2862 {
2863 struct ssh_channels *sc = ssh->chanctxt;
2864 u_int i;
2865 int p;
2866 Channel *c;
2867
2868 #ifdef DEBUG_CHANNEL_POLL
2869 for (p = 0; p < (int)npfd; p++) {
2870 if (pfd[p].revents == 0)
2871 continue;
2872 debug_f("pfd[%u].fd %d rev 0x%04x",
2873 p, pfd[p].fd, pfd[p].revents);
2874 }
2875 #endif
2876
2877 /* Convert pollfd into c->io_ready */
2878 for (i = 0; i < sc->channels_alloc; i++) {
2879 c = sc->channels[i];
2880 if (c == NULL)
2881 continue;
2882 /* if rfd is shared with efd/sock then wfd should be too */
2883 if (c->rfd != -1 && c->wfd != -1 && c->rfd != c->wfd &&
2884 (c->rfd == c->efd || c->rfd == c->sock)) {
2885 /* Shouldn't happen */
2886 fatal_f("channel %d: unexpected fds r%d w%d e%d s%d",
2887 c->self, c->rfd, c->wfd, c->efd, c->sock);
2888 }
2889 c->io_ready = 0;
2890 /* rfd, potentially shared with wfd, efd and sock */
2891 if (c->rfd != -1 && (p = c->pfds[0]) != -1) {
2892 fd_ready(c, p, pfd, npfd, c->rfd,
2893 "rfd", POLLIN, SSH_CHAN_IO_RFD);
2894 if (c->rfd == c->wfd) {
2895 fd_ready(c, p, pfd, npfd, c->wfd,
2896 "wfd/r", POLLOUT, SSH_CHAN_IO_WFD);
2897 }
2898 if (c->rfd == c->efd) {
2899 fd_ready(c, p, pfd, npfd, c->efd,
2900 "efdr/r", POLLIN, SSH_CHAN_IO_EFD_R);
2901 fd_ready(c, p, pfd, npfd, c->efd,
2902 "efdw/r", POLLOUT, SSH_CHAN_IO_EFD_W);
2903 }
2904 if (c->rfd == c->sock) {
2905 fd_ready(c, p, pfd, npfd, c->sock,
2906 "sockr/r", POLLIN, SSH_CHAN_IO_SOCK_R);
2907 fd_ready(c, p, pfd, npfd, c->sock,
2908 "sockw/r", POLLOUT, SSH_CHAN_IO_SOCK_W);
2909 }
2910 dump_channel_poll(__func__, "rfd", c, p, pfd);
2911 }
2912 /* wfd */
2913 if (c->wfd != -1 && c->wfd != c->rfd &&
2914 (p = c->pfds[1]) != -1) {
2915 fd_ready(c, p, pfd, npfd, c->wfd,
2916 "wfd", POLLOUT, SSH_CHAN_IO_WFD);
2917 dump_channel_poll(__func__, "wfd", c, p, pfd);
2918 }
2919 /* efd */
2920 if (c->efd != -1 && c->efd != c->rfd &&
2921 (p = c->pfds[2]) != -1) {
2922 fd_ready(c, p, pfd, npfd, c->efd,
2923 "efdr", POLLIN, SSH_CHAN_IO_EFD_R);
2924 fd_ready(c, p, pfd, npfd, c->efd,
2925 "efdw", POLLOUT, SSH_CHAN_IO_EFD_W);
2926 dump_channel_poll(__func__, "efd", c, p, pfd);
2927 }
2928 /* sock */
2929 if (c->sock != -1 && c->sock != c->rfd &&
2930 (p = c->pfds[3]) != -1) {
2931 fd_ready(c, p, pfd, npfd, c->sock,
2932 "sockr", POLLIN, SSH_CHAN_IO_SOCK_R);
2933 fd_ready(c, p, pfd, npfd, c->sock,
2934 "sockw", POLLOUT, SSH_CHAN_IO_SOCK_W);
2935 dump_channel_poll(__func__, "sock", c, p, pfd);
2936 }
2937 }
2938 channel_handler(ssh, CHAN_POST, NULL);
2939 }
2940
2941 /*
2942 * Enqueue data for channels with open or draining c->input.
2943 * Returns non-zero if a packet was enqueued.
2944 */
2945 static int
channel_output_poll_input_open(struct ssh * ssh,Channel * c)2946 channel_output_poll_input_open(struct ssh *ssh, Channel *c)
2947 {
2948 size_t len, plen;
2949 const u_char *pkt;
2950 int r;
2951
2952 if ((len = sshbuf_len(c->input)) == 0) {
2953 if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
2954 /*
2955 * input-buffer is empty and read-socket shutdown:
2956 * tell peer, that we will not send more data:
2957 * send IEOF.
2958 * hack for extended data: delay EOF if EFD still
2959 * in use.
2960 */
2961 if (CHANNEL_EFD_INPUT_ACTIVE(c))
2962 debug2("channel %d: "
2963 "ibuf_empty delayed efd %d/(%zu)",
2964 c->self, c->efd, sshbuf_len(c->extended));
2965 else
2966 chan_ibuf_empty(ssh, c);
2967 }
2968 return 0;
2969 }
2970
2971 if (!c->have_remote_id)
2972 fatal_f("channel %d: no remote id", c->self);
2973
2974 if (c->datagram) {
2975 /* Check datagram will fit; drop if not */
2976 if ((r = sshbuf_get_string_direct(c->input, &pkt, &plen)) != 0)
2977 fatal_fr(r, "channel %i: get datagram", c->self);
2978 /*
2979 * XXX this does tail-drop on the datagram queue which is
2980 * usually suboptimal compared to head-drop. Better to have
2981 * backpressure at read time? (i.e. read + discard)
2982 */
2983 if (plen > c->remote_window || plen > c->remote_maxpacket) {
2984 debug("channel %d: datagram too big", c->self);
2985 return 0;
2986 }
2987 /* Enqueue it */
2988 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 ||
2989 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 ||
2990 (r = sshpkt_put_string(ssh, pkt, plen)) != 0 ||
2991 (r = sshpkt_send(ssh)) != 0)
2992 fatal_fr(r, "channel %i: send datagram", c->self);
2993 c->remote_window -= plen;
2994 return 1;
2995 }
2996
2997 /* Enqueue packet for buffered data. */
2998 if (len > c->remote_window)
2999 len = c->remote_window;
3000 if (len > c->remote_maxpacket)
3001 len = c->remote_maxpacket;
3002 if (len == 0)
3003 return 0;
3004 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 ||
3005 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 ||
3006 (r = sshpkt_put_string(ssh, sshbuf_ptr(c->input), len)) != 0 ||
3007 (r = sshpkt_send(ssh)) != 0)
3008 fatal_fr(r, "channel %i: send data", c->self);
3009 if ((r = sshbuf_consume(c->input, len)) != 0)
3010 fatal_fr(r, "channel %i: consume", c->self);
3011 c->remote_window -= len;
3012 return 1;
3013 }
3014
3015 /*
3016 * Enqueue data for channels with open c->extended in read mode.
3017 * Returns non-zero if a packet was enqueued.
3018 */
3019 static int
channel_output_poll_extended_read(struct ssh * ssh,Channel * c)3020 channel_output_poll_extended_read(struct ssh *ssh, Channel *c)
3021 {
3022 size_t len;
3023 int r;
3024
3025 if ((len = sshbuf_len(c->extended)) == 0)
3026 return 0;
3027
3028 debug2("channel %d: rwin %u elen %zu euse %d", c->self,
3029 c->remote_window, sshbuf_len(c->extended), c->extended_usage);
3030 if (len > c->remote_window)
3031 len = c->remote_window;
3032 if (len > c->remote_maxpacket)
3033 len = c->remote_maxpacket;
3034 if (len == 0)
3035 return 0;
3036 if (!c->have_remote_id)
3037 fatal_f("channel %d: no remote id", c->self);
3038 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_EXTENDED_DATA)) != 0 ||
3039 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 ||
3040 (r = sshpkt_put_u32(ssh, SSH2_EXTENDED_DATA_STDERR)) != 0 ||
3041 (r = sshpkt_put_string(ssh, sshbuf_ptr(c->extended), len)) != 0 ||
3042 (r = sshpkt_send(ssh)) != 0)
3043 fatal_fr(r, "channel %i: data", c->self);
3044 if ((r = sshbuf_consume(c->extended, len)) != 0)
3045 fatal_fr(r, "channel %i: consume", c->self);
3046 c->remote_window -= len;
3047 debug2("channel %d: sent ext data %zu", c->self, len);
3048 return 1;
3049 }
3050
3051 /*
3052 * If there is data to send to the connection, enqueue some of it now.
3053 * Returns non-zero if data was enqueued.
3054 */
3055 int
channel_output_poll(struct ssh * ssh)3056 channel_output_poll(struct ssh *ssh)
3057 {
3058 struct ssh_channels *sc = ssh->chanctxt;
3059 Channel *c;
3060 u_int i;
3061 int ret = 0;
3062
3063 for (i = 0; i < sc->channels_alloc; i++) {
3064 c = sc->channels[i];
3065 if (c == NULL)
3066 continue;
3067
3068 /*
3069 * We are only interested in channels that can have buffered
3070 * incoming data.
3071 */
3072 if (c->type != SSH_CHANNEL_OPEN)
3073 continue;
3074 if ((c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
3075 /* XXX is this true? */
3076 debug3("channel %d: will not send data after close",
3077 c->self);
3078 continue;
3079 }
3080
3081 /* Get the amount of buffered data for this channel. */
3082 if (c->istate == CHAN_INPUT_OPEN ||
3083 c->istate == CHAN_INPUT_WAIT_DRAIN)
3084 ret |= channel_output_poll_input_open(ssh, c);
3085 /* Send extended data, i.e. stderr */
3086 if (!(c->flags & CHAN_EOF_SENT) &&
3087 c->extended_usage == CHAN_EXTENDED_READ)
3088 ret |= channel_output_poll_extended_read(ssh, c);
3089 }
3090 return ret;
3091 }
3092
3093 /* -- mux proxy support */
3094
3095 /*
3096 * When multiplexing channel messages for mux clients we have to deal
3097 * with downstream messages from the mux client and upstream messages
3098 * from the ssh server:
3099 * 1) Handling downstream messages is straightforward and happens
3100 * in channel_proxy_downstream():
3101 * - We forward all messages (mostly) unmodified to the server.
3102 * - However, in order to route messages from upstream to the correct
3103 * downstream client, we have to replace the channel IDs used by the
3104 * mux clients with a unique channel ID because the mux clients might
3105 * use conflicting channel IDs.
3106 * - so we inspect and change both SSH2_MSG_CHANNEL_OPEN and
3107 * SSH2_MSG_CHANNEL_OPEN_CONFIRMATION messages, create a local
3108 * SSH_CHANNEL_MUX_PROXY channel and replace the mux clients ID
3109 * with the newly allocated channel ID.
3110 * 2) Upstream messages are received by matching SSH_CHANNEL_MUX_PROXY
3111 * channels and processed by channel_proxy_upstream(). The local channel ID
3112 * is then translated back to the original mux client ID.
3113 * 3) In both cases we need to keep track of matching SSH2_MSG_CHANNEL_CLOSE
3114 * messages so we can clean up SSH_CHANNEL_MUX_PROXY channels.
3115 * 4) The SSH_CHANNEL_MUX_PROXY channels also need to closed when the
3116 * downstream mux client are removed.
3117 * 5) Handling SSH2_MSG_CHANNEL_OPEN messages from the upstream server
3118 * requires more work, because they are not addressed to a specific
3119 * channel. E.g. client_request_forwarded_tcpip() needs to figure
3120 * out whether the request is addressed to the local client or a
3121 * specific downstream client based on the listen-address/port.
3122 * 6) Agent and X11-Forwarding have a similar problem and are currently
3123 * not supported as the matching session/channel cannot be identified
3124 * easily.
3125 */
3126
3127 /*
3128 * receive packets from downstream mux clients:
3129 * channel callback fired on read from mux client, creates
3130 * SSH_CHANNEL_MUX_PROXY channels and translates channel IDs
3131 * on channel creation.
3132 */
3133 int
channel_proxy_downstream(struct ssh * ssh,Channel * downstream)3134 channel_proxy_downstream(struct ssh *ssh, Channel *downstream)
3135 {
3136 Channel *c = NULL;
3137 struct sshbuf *original = NULL, *modified = NULL;
3138 const u_char *cp;
3139 char *ctype = NULL, *listen_host = NULL;
3140 u_char type;
3141 size_t have;
3142 int ret = -1, r;
3143 u_int id, remote_id, listen_port;
3144
3145 /* sshbuf_dump(downstream->input, stderr); */
3146 if ((r = sshbuf_get_string_direct(downstream->input, &cp, &have))
3147 != 0) {
3148 error_fr(r, "parse");
3149 return -1;
3150 }
3151 if (have < 2) {
3152 error_f("short message");
3153 return -1;
3154 }
3155 type = cp[1];
3156 /* skip padlen + type */
3157 cp += 2;
3158 have -= 2;
3159 if (ssh_packet_log_type(type))
3160 debug3_f("channel %u: down->up: type %u",
3161 downstream->self, type);
3162
3163 switch (type) {
3164 case SSH2_MSG_CHANNEL_OPEN:
3165 if ((original = sshbuf_from(cp, have)) == NULL ||
3166 (modified = sshbuf_new()) == NULL) {
3167 error_f("alloc");
3168 goto out;
3169 }
3170 if ((r = sshbuf_get_cstring(original, &ctype, NULL)) != 0 ||
3171 (r = sshbuf_get_u32(original, &id)) != 0) {
3172 error_fr(r, "parse");
3173 goto out;
3174 }
3175 c = channel_new(ssh, "mux-proxy", SSH_CHANNEL_MUX_PROXY,
3176 -1, -1, -1, 0, 0, 0, ctype, 1);
3177 c->mux_ctx = downstream; /* point to mux client */
3178 c->mux_downstream_id = id; /* original downstream id */
3179 if ((r = sshbuf_put_cstring(modified, ctype)) != 0 ||
3180 (r = sshbuf_put_u32(modified, c->self)) != 0 ||
3181 (r = sshbuf_putb(modified, original)) != 0) {
3182 error_fr(r, "compose");
3183 channel_free(ssh, c);
3184 goto out;
3185 }
3186 break;
3187 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION:
3188 /*
3189 * Almost the same as SSH2_MSG_CHANNEL_OPEN, except then we
3190 * need to parse 'remote_id' instead of 'ctype'.
3191 */
3192 if ((original = sshbuf_from(cp, have)) == NULL ||
3193 (modified = sshbuf_new()) == NULL) {
3194 error_f("alloc");
3195 goto out;
3196 }
3197 if ((r = sshbuf_get_u32(original, &remote_id)) != 0 ||
3198 (r = sshbuf_get_u32(original, &id)) != 0) {
3199 error_fr(r, "parse");
3200 goto out;
3201 }
3202 c = channel_new(ssh, "mux-proxy", SSH_CHANNEL_MUX_PROXY,
3203 -1, -1, -1, 0, 0, 0, "mux-down-connect", 1);
3204 c->mux_ctx = downstream; /* point to mux client */
3205 c->mux_downstream_id = id;
3206 c->remote_id = remote_id;
3207 c->have_remote_id = 1;
3208 if ((r = sshbuf_put_u32(modified, remote_id)) != 0 ||
3209 (r = sshbuf_put_u32(modified, c->self)) != 0 ||
3210 (r = sshbuf_putb(modified, original)) != 0) {
3211 error_fr(r, "compose");
3212 channel_free(ssh, c);
3213 goto out;
3214 }
3215 break;
3216 case SSH2_MSG_GLOBAL_REQUEST:
3217 if ((original = sshbuf_from(cp, have)) == NULL) {
3218 error_f("alloc");
3219 goto out;
3220 }
3221 if ((r = sshbuf_get_cstring(original, &ctype, NULL)) != 0) {
3222 error_fr(r, "parse");
3223 goto out;
3224 }
3225 if (strcmp(ctype, "tcpip-forward") != 0) {
3226 error_f("unsupported request %s", ctype);
3227 goto out;
3228 }
3229 if ((r = sshbuf_get_u8(original, NULL)) != 0 ||
3230 (r = sshbuf_get_cstring(original, &listen_host, NULL)) != 0 ||
3231 (r = sshbuf_get_u32(original, &listen_port)) != 0) {
3232 error_fr(r, "parse");
3233 goto out;
3234 }
3235 if (listen_port > 65535) {
3236 error_f("tcpip-forward for %s: bad port %u",
3237 listen_host, listen_port);
3238 goto out;
3239 }
3240 /* Record that connection to this host/port is permitted. */
3241 permission_set_add(ssh, FORWARD_USER, FORWARD_LOCAL, "<mux>",
3242 -1, listen_host, NULL, (int)listen_port, downstream);
3243 break;
3244 case SSH2_MSG_CHANNEL_CLOSE:
3245 if (have < 4)
3246 break;
3247 remote_id = PEEK_U32(cp);
3248 if ((c = channel_by_remote_id(ssh, remote_id)) != NULL) {
3249 if (c->flags & CHAN_CLOSE_RCVD)
3250 channel_free(ssh, c);
3251 else
3252 c->flags |= CHAN_CLOSE_SENT;
3253 }
3254 break;
3255 }
3256 if (modified) {
3257 if ((r = sshpkt_start(ssh, type)) != 0 ||
3258 (r = sshpkt_putb(ssh, modified)) != 0 ||
3259 (r = sshpkt_send(ssh)) != 0) {
3260 error_fr(r, "send");
3261 goto out;
3262 }
3263 } else {
3264 if ((r = sshpkt_start(ssh, type)) != 0 ||
3265 (r = sshpkt_put(ssh, cp, have)) != 0 ||
3266 (r = sshpkt_send(ssh)) != 0) {
3267 error_fr(r, "send");
3268 goto out;
3269 }
3270 }
3271 ret = 0;
3272 out:
3273 free(ctype);
3274 free(listen_host);
3275 sshbuf_free(original);
3276 sshbuf_free(modified);
3277 return ret;
3278 }
3279
3280 /*
3281 * receive packets from upstream server and de-multiplex packets
3282 * to correct downstream:
3283 * implemented as a helper for channel input handlers,
3284 * replaces local (proxy) channel ID with downstream channel ID.
3285 */
3286 int
channel_proxy_upstream(Channel * c,int type,u_int32_t seq,struct ssh * ssh)3287 channel_proxy_upstream(Channel *c, int type, u_int32_t seq, struct ssh *ssh)
3288 {
3289 struct sshbuf *b = NULL;
3290 Channel *downstream;
3291 const u_char *cp = NULL;
3292 size_t len;
3293 int r;
3294
3295 /*
3296 * When receiving packets from the peer we need to check whether we
3297 * need to forward the packets to the mux client. In this case we
3298 * restore the original channel id and keep track of CLOSE messages,
3299 * so we can cleanup the channel.
3300 */
3301 if (c == NULL || c->type != SSH_CHANNEL_MUX_PROXY)
3302 return 0;
3303 if ((downstream = c->mux_ctx) == NULL)
3304 return 0;
3305 switch (type) {
3306 case SSH2_MSG_CHANNEL_CLOSE:
3307 case SSH2_MSG_CHANNEL_DATA:
3308 case SSH2_MSG_CHANNEL_EOF:
3309 case SSH2_MSG_CHANNEL_EXTENDED_DATA:
3310 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION:
3311 case SSH2_MSG_CHANNEL_OPEN_FAILURE:
3312 case SSH2_MSG_CHANNEL_WINDOW_ADJUST:
3313 case SSH2_MSG_CHANNEL_SUCCESS:
3314 case SSH2_MSG_CHANNEL_FAILURE:
3315 case SSH2_MSG_CHANNEL_REQUEST:
3316 break;
3317 default:
3318 debug2_f("channel %u: unsupported type %u", c->self, type);
3319 return 0;
3320 }
3321 if ((b = sshbuf_new()) == NULL) {
3322 error_f("alloc reply");
3323 goto out;
3324 }
3325 /* get remaining payload (after id) */
3326 cp = sshpkt_ptr(ssh, &len);
3327 if (cp == NULL) {
3328 error_f("no packet");
3329 goto out;
3330 }
3331 /* translate id and send to muxclient */
3332 if ((r = sshbuf_put_u8(b, 0)) != 0 || /* padlen */
3333 (r = sshbuf_put_u8(b, type)) != 0 ||
3334 (r = sshbuf_put_u32(b, c->mux_downstream_id)) != 0 ||
3335 (r = sshbuf_put(b, cp, len)) != 0 ||
3336 (r = sshbuf_put_stringb(downstream->output, b)) != 0) {
3337 error_fr(r, "compose muxclient");
3338 goto out;
3339 }
3340 /* sshbuf_dump(b, stderr); */
3341 if (ssh_packet_log_type(type))
3342 debug3_f("channel %u: up->down: type %u", c->self, type);
3343 out:
3344 /* update state */
3345 switch (type) {
3346 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION:
3347 /* record remote_id for SSH2_MSG_CHANNEL_CLOSE */
3348 if (cp && len > 4) {
3349 c->remote_id = PEEK_U32(cp);
3350 c->have_remote_id = 1;
3351 }
3352 break;
3353 case SSH2_MSG_CHANNEL_CLOSE:
3354 if (c->flags & CHAN_CLOSE_SENT)
3355 channel_free(ssh, c);
3356 else
3357 c->flags |= CHAN_CLOSE_RCVD;
3358 break;
3359 }
3360 sshbuf_free(b);
3361 return 1;
3362 }
3363
3364 /* -- protocol input */
3365
3366 /* Parse a channel ID from the current packet */
3367 static int
channel_parse_id(struct ssh * ssh,const char * where,const char * what)3368 channel_parse_id(struct ssh *ssh, const char *where, const char *what)
3369 {
3370 u_int32_t id;
3371 int r;
3372
3373 if ((r = sshpkt_get_u32(ssh, &id)) != 0) {
3374 error_r(r, "%s: parse id", where);
3375 ssh_packet_disconnect(ssh, "Invalid %s message", what);
3376 }
3377 if (id > INT_MAX) {
3378 error_r(r, "%s: bad channel id %u", where, id);
3379 ssh_packet_disconnect(ssh, "Invalid %s channel id", what);
3380 }
3381 return (int)id;
3382 }
3383
3384 /* Lookup a channel from an ID in the current packet */
3385 static Channel *
channel_from_packet_id(struct ssh * ssh,const char * where,const char * what)3386 channel_from_packet_id(struct ssh *ssh, const char *where, const char *what)
3387 {
3388 int id = channel_parse_id(ssh, where, what);
3389 Channel *c;
3390
3391 if ((c = channel_lookup(ssh, id)) == NULL) {
3392 ssh_packet_disconnect(ssh,
3393 "%s packet referred to nonexistent channel %d", what, id);
3394 }
3395 return c;
3396 }
3397
3398 int
channel_input_data(int type,u_int32_t seq,struct ssh * ssh)3399 channel_input_data(int type, u_int32_t seq, struct ssh *ssh)
3400 {
3401 const u_char *data;
3402 size_t data_len, win_len;
3403 Channel *c = channel_from_packet_id(ssh, __func__, "data");
3404 int r;
3405
3406 if (channel_proxy_upstream(c, type, seq, ssh))
3407 return 0;
3408
3409 /* Ignore any data for non-open channels (might happen on close) */
3410 if (c->type != SSH_CHANNEL_OPEN &&
3411 c->type != SSH_CHANNEL_RDYNAMIC_OPEN &&
3412 c->type != SSH_CHANNEL_RDYNAMIC_FINISH &&
3413 c->type != SSH_CHANNEL_X11_OPEN)
3414 return 0;
3415
3416 /* Get the data. */
3417 if ((r = sshpkt_get_string_direct(ssh, &data, &data_len)) != 0 ||
3418 (r = sshpkt_get_end(ssh)) != 0)
3419 fatal_fr(r, "channel %i: get data", c->self);
3420
3421 win_len = data_len;
3422 if (c->datagram)
3423 win_len += 4; /* string length header */
3424
3425 /*
3426 * The sending side reduces its window as it sends data, so we
3427 * must 'fake' consumption of the data in order to ensure that window
3428 * updates are sent back. Otherwise the connection might deadlock.
3429 */
3430 if (c->ostate != CHAN_OUTPUT_OPEN) {
3431 c->local_window -= win_len;
3432 c->local_consumed += win_len;
3433 return 0;
3434 }
3435
3436 if (win_len > c->local_maxpacket) {
3437 logit("channel %d: rcvd big packet %zu, maxpack %u",
3438 c->self, win_len, c->local_maxpacket);
3439 return 0;
3440 }
3441 if (win_len > c->local_window) {
3442 c->local_window_exceeded += win_len - c->local_window;
3443 logit("channel %d: rcvd too much data %zu, win %u/%u "
3444 "(excess %u)", c->self, win_len, c->local_window,
3445 c->local_window_max, c->local_window_exceeded);
3446 c->local_window = 0;
3447 /* Allow 10% grace before bringing the hammer down */
3448 if (c->local_window_exceeded > (c->local_window_max / 10)) {
3449 ssh_packet_disconnect(ssh, "channel %d: peer ignored "
3450 "channel window", c->self);
3451 }
3452 } else {
3453 c->local_window -= win_len;
3454 c->local_window_exceeded = 0;
3455 }
3456
3457 if (c->datagram) {
3458 if ((r = sshbuf_put_string(c->output, data, data_len)) != 0)
3459 fatal_fr(r, "channel %i: append datagram", c->self);
3460 } else if ((r = sshbuf_put(c->output, data, data_len)) != 0)
3461 fatal_fr(r, "channel %i: append data", c->self);
3462
3463 return 0;
3464 }
3465
3466 int
channel_input_extended_data(int type,u_int32_t seq,struct ssh * ssh)3467 channel_input_extended_data(int type, u_int32_t seq, struct ssh *ssh)
3468 {
3469 const u_char *data;
3470 size_t data_len;
3471 u_int32_t tcode;
3472 Channel *c = channel_from_packet_id(ssh, __func__, "extended data");
3473 int r;
3474
3475 if (channel_proxy_upstream(c, type, seq, ssh))
3476 return 0;
3477 if (c->type != SSH_CHANNEL_OPEN) {
3478 logit("channel %d: ext data for non open", c->self);
3479 return 0;
3480 }
3481 if (c->flags & CHAN_EOF_RCVD) {
3482 if (ssh->compat & SSH_BUG_EXTEOF)
3483 debug("channel %d: accepting ext data after eof",
3484 c->self);
3485 else
3486 ssh_packet_disconnect(ssh, "Received extended_data "
3487 "after EOF on channel %d.", c->self);
3488 }
3489
3490 if ((r = sshpkt_get_u32(ssh, &tcode)) != 0) {
3491 error_fr(r, "parse tcode");
3492 ssh_packet_disconnect(ssh, "Invalid extended_data message");
3493 }
3494 if (c->efd == -1 ||
3495 c->extended_usage != CHAN_EXTENDED_WRITE ||
3496 tcode != SSH2_EXTENDED_DATA_STDERR) {
3497 logit("channel %d: bad ext data", c->self);
3498 return 0;
3499 }
3500 if ((r = sshpkt_get_string_direct(ssh, &data, &data_len)) != 0 ||
3501 (r = sshpkt_get_end(ssh)) != 0) {
3502 error_fr(r, "parse data");
3503 ssh_packet_disconnect(ssh, "Invalid extended_data message");
3504 }
3505
3506 if (data_len > c->local_window) {
3507 logit("channel %d: rcvd too much extended_data %zu, win %u",
3508 c->self, data_len, c->local_window);
3509 return 0;
3510 }
3511 debug2("channel %d: rcvd ext data %zu", c->self, data_len);
3512 /* XXX sshpkt_getb? */
3513 if ((r = sshbuf_put(c->extended, data, data_len)) != 0)
3514 error_fr(r, "append");
3515 c->local_window -= data_len;
3516 return 0;
3517 }
3518
3519 int
channel_input_ieof(int type,u_int32_t seq,struct ssh * ssh)3520 channel_input_ieof(int type, u_int32_t seq, struct ssh *ssh)
3521 {
3522 Channel *c = channel_from_packet_id(ssh, __func__, "ieof");
3523 int r;
3524
3525 if ((r = sshpkt_get_end(ssh)) != 0) {
3526 error_fr(r, "parse data");
3527 ssh_packet_disconnect(ssh, "Invalid ieof message");
3528 }
3529
3530 if (channel_proxy_upstream(c, type, seq, ssh))
3531 return 0;
3532 chan_rcvd_ieof(ssh, c);
3533
3534 /* XXX force input close */
3535 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) {
3536 debug("channel %d: FORCE input drain", c->self);
3537 c->istate = CHAN_INPUT_WAIT_DRAIN;
3538 if (sshbuf_len(c->input) == 0)
3539 chan_ibuf_empty(ssh, c);
3540 }
3541 return 0;
3542 }
3543
3544 int
channel_input_oclose(int type,u_int32_t seq,struct ssh * ssh)3545 channel_input_oclose(int type, u_int32_t seq, struct ssh *ssh)
3546 {
3547 Channel *c = channel_from_packet_id(ssh, __func__, "oclose");
3548 int r;
3549
3550 if (channel_proxy_upstream(c, type, seq, ssh))
3551 return 0;
3552 if ((r = sshpkt_get_end(ssh)) != 0) {
3553 error_fr(r, "parse data");
3554 ssh_packet_disconnect(ssh, "Invalid oclose message");
3555 }
3556 chan_rcvd_oclose(ssh, c);
3557 return 0;
3558 }
3559
3560 int
channel_input_open_confirmation(int type,u_int32_t seq,struct ssh * ssh)3561 channel_input_open_confirmation(int type, u_int32_t seq, struct ssh *ssh)
3562 {
3563 Channel *c = channel_from_packet_id(ssh, __func__, "open confirmation");
3564 u_int32_t remote_window, remote_maxpacket;
3565 int r;
3566
3567 if (channel_proxy_upstream(c, type, seq, ssh))
3568 return 0;
3569 if (c->type != SSH_CHANNEL_OPENING)
3570 ssh_packet_disconnect(ssh, "Received open confirmation for "
3571 "non-opening channel %d.", c->self);
3572 /*
3573 * Record the remote channel number and mark that the channel
3574 * is now open.
3575 */
3576 if ((r = sshpkt_get_u32(ssh, &c->remote_id)) != 0 ||
3577 (r = sshpkt_get_u32(ssh, &remote_window)) != 0 ||
3578 (r = sshpkt_get_u32(ssh, &remote_maxpacket)) != 0 ||
3579 (r = sshpkt_get_end(ssh)) != 0) {
3580 error_fr(r, "window/maxpacket");
3581 ssh_packet_disconnect(ssh, "Invalid open confirmation message");
3582 }
3583
3584 c->have_remote_id = 1;
3585 c->remote_window = remote_window;
3586 c->remote_maxpacket = remote_maxpacket;
3587 c->type = SSH_CHANNEL_OPEN;
3588 if (c->open_confirm) {
3589 debug2_f("channel %d: callback start", c->self);
3590 c->open_confirm(ssh, c->self, 1, c->open_confirm_ctx);
3591 debug2_f("channel %d: callback done", c->self);
3592 }
3593 channel_set_used_time(ssh, c);
3594 debug2("channel %d: open confirm rwindow %u rmax %u", c->self,
3595 c->remote_window, c->remote_maxpacket);
3596 return 0;
3597 }
3598
3599 static char *
reason2txt(int reason)3600 reason2txt(int reason)
3601 {
3602 switch (reason) {
3603 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
3604 return "administratively prohibited";
3605 case SSH2_OPEN_CONNECT_FAILED:
3606 return "connect failed";
3607 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
3608 return "unknown channel type";
3609 case SSH2_OPEN_RESOURCE_SHORTAGE:
3610 return "resource shortage";
3611 }
3612 return "unknown reason";
3613 }
3614
3615 int
channel_input_open_failure(int type,u_int32_t seq,struct ssh * ssh)3616 channel_input_open_failure(int type, u_int32_t seq, struct ssh *ssh)
3617 {
3618 Channel *c = channel_from_packet_id(ssh, __func__, "open failure");
3619 u_int32_t reason;
3620 char *msg = NULL;
3621 int r;
3622
3623 if (channel_proxy_upstream(c, type, seq, ssh))
3624 return 0;
3625 if (c->type != SSH_CHANNEL_OPENING)
3626 ssh_packet_disconnect(ssh, "Received open failure for "
3627 "non-opening channel %d.", c->self);
3628 if ((r = sshpkt_get_u32(ssh, &reason)) != 0) {
3629 error_fr(r, "parse reason");
3630 ssh_packet_disconnect(ssh, "Invalid open failure message");
3631 }
3632 /* skip language */
3633 if ((r = sshpkt_get_cstring(ssh, &msg, NULL)) != 0 ||
3634 (r = sshpkt_get_string_direct(ssh, NULL, NULL)) != 0 ||
3635 (r = sshpkt_get_end(ssh)) != 0) {
3636 error_fr(r, "parse msg/lang");
3637 ssh_packet_disconnect(ssh, "Invalid open failure message");
3638 }
3639 logit("channel %d: open failed: %s%s%s", c->self,
3640 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
3641 free(msg);
3642 if (c->open_confirm) {
3643 debug2_f("channel %d: callback start", c->self);
3644 c->open_confirm(ssh, c->self, 0, c->open_confirm_ctx);
3645 debug2_f("channel %d: callback done", c->self);
3646 }
3647 /* Schedule the channel for cleanup/deletion. */
3648 chan_mark_dead(ssh, c);
3649 return 0;
3650 }
3651
3652 int
channel_input_window_adjust(int type,u_int32_t seq,struct ssh * ssh)3653 channel_input_window_adjust(int type, u_int32_t seq, struct ssh *ssh)
3654 {
3655 int id = channel_parse_id(ssh, __func__, "window adjust");
3656 Channel *c;
3657 u_int32_t adjust;
3658 u_int new_rwin;
3659 int r;
3660
3661 if ((c = channel_lookup(ssh, id)) == NULL) {
3662 logit("Received window adjust for non-open channel %d.", id);
3663 return 0;
3664 }
3665
3666 if (channel_proxy_upstream(c, type, seq, ssh))
3667 return 0;
3668 if ((r = sshpkt_get_u32(ssh, &adjust)) != 0 ||
3669 (r = sshpkt_get_end(ssh)) != 0) {
3670 error_fr(r, "parse adjust");
3671 ssh_packet_disconnect(ssh, "Invalid window adjust message");
3672 }
3673 debug2("channel %d: rcvd adjust %u", c->self, adjust);
3674 if ((new_rwin = c->remote_window + adjust) < c->remote_window) {
3675 fatal("channel %d: adjust %u overflows remote window %u",
3676 c->self, adjust, c->remote_window);
3677 }
3678 c->remote_window = new_rwin;
3679 return 0;
3680 }
3681
3682 int
channel_input_status_confirm(int type,u_int32_t seq,struct ssh * ssh)3683 channel_input_status_confirm(int type, u_int32_t seq, struct ssh *ssh)
3684 {
3685 int id = channel_parse_id(ssh, __func__, "status confirm");
3686 Channel *c;
3687 struct channel_confirm *cc;
3688
3689 /* Reset keepalive timeout */
3690 ssh_packet_set_alive_timeouts(ssh, 0);
3691
3692 debug2_f("type %d id %d", type, id);
3693
3694 if ((c = channel_lookup(ssh, id)) == NULL) {
3695 logit_f("%d: unknown", id);
3696 return 0;
3697 }
3698 if (channel_proxy_upstream(c, type, seq, ssh))
3699 return 0;
3700 if (sshpkt_get_end(ssh) != 0)
3701 ssh_packet_disconnect(ssh, "Invalid status confirm message");
3702 if ((cc = TAILQ_FIRST(&c->status_confirms)) == NULL)
3703 return 0;
3704 cc->cb(ssh, type, c, cc->ctx);
3705 TAILQ_REMOVE(&c->status_confirms, cc, entry);
3706 freezero(cc, sizeof(*cc));
3707 return 0;
3708 }
3709
3710 /* -- tcp forwarding */
3711
3712 void
channel_set_af(struct ssh * ssh,int af)3713 channel_set_af(struct ssh *ssh, int af)
3714 {
3715 ssh->chanctxt->IPv4or6 = af;
3716 }
3717
3718
3719 /*
3720 * Determine whether or not a port forward listens to loopback, the
3721 * specified address or wildcard. On the client, a specified bind
3722 * address will always override gateway_ports. On the server, a
3723 * gateway_ports of 1 (``yes'') will override the client's specification
3724 * and force a wildcard bind, whereas a value of 2 (``clientspecified'')
3725 * will bind to whatever address the client asked for.
3726 *
3727 * Special-case listen_addrs are:
3728 *
3729 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR
3730 * "" (empty string), "*" -> wildcard v4/v6
3731 * "localhost" -> loopback v4/v6
3732 * "127.0.0.1" / "::1" -> accepted even if gateway_ports isn't set
3733 */
3734 static const char *
channel_fwd_bind_addr(struct ssh * ssh,const char * listen_addr,int * wildcardp,int is_client,struct ForwardOptions * fwd_opts)3735 channel_fwd_bind_addr(struct ssh *ssh, const char *listen_addr, int *wildcardp,
3736 int is_client, struct ForwardOptions *fwd_opts)
3737 {
3738 const char *addr = NULL;
3739 int wildcard = 0;
3740
3741 if (listen_addr == NULL) {
3742 /* No address specified: default to gateway_ports setting */
3743 if (fwd_opts->gateway_ports)
3744 wildcard = 1;
3745 } else if (fwd_opts->gateway_ports || is_client) {
3746 if (((ssh->compat & SSH_OLD_FORWARD_ADDR) &&
3747 strcmp(listen_addr, "0.0.0.0") == 0 && is_client == 0) ||
3748 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 ||
3749 (!is_client && fwd_opts->gateway_ports == 1)) {
3750 wildcard = 1;
3751 /*
3752 * Notify client if they requested a specific listen
3753 * address and it was overridden.
3754 */
3755 if (*listen_addr != '\0' &&
3756 strcmp(listen_addr, "0.0.0.0") != 0 &&
3757 strcmp(listen_addr, "*") != 0) {
3758 ssh_packet_send_debug(ssh,
3759 "Forwarding listen address "
3760 "\"%s\" overridden by server "
3761 "GatewayPorts", listen_addr);
3762 }
3763 } else if (strcmp(listen_addr, "localhost") != 0 ||
3764 strcmp(listen_addr, "127.0.0.1") == 0 ||
3765 strcmp(listen_addr, "::1") == 0) {
3766 /*
3767 * Accept explicit localhost address when
3768 * GatewayPorts=yes. The "localhost" hostname is
3769 * deliberately skipped here so it will listen on all
3770 * available local address families.
3771 */
3772 addr = listen_addr;
3773 }
3774 } else if (strcmp(listen_addr, "127.0.0.1") == 0 ||
3775 strcmp(listen_addr, "::1") == 0) {
3776 /*
3777 * If a specific IPv4/IPv6 localhost address has been
3778 * requested then accept it even if gateway_ports is in
3779 * effect. This allows the client to prefer IPv4 or IPv6.
3780 */
3781 addr = listen_addr;
3782 }
3783 if (wildcardp != NULL)
3784 *wildcardp = wildcard;
3785 return addr;
3786 }
3787
3788 static int
channel_setup_fwd_listener_tcpip(struct ssh * ssh,int type,struct Forward * fwd,int * allocated_listen_port,struct ForwardOptions * fwd_opts)3789 channel_setup_fwd_listener_tcpip(struct ssh *ssh, int type,
3790 struct Forward *fwd, int *allocated_listen_port,
3791 struct ForwardOptions *fwd_opts)
3792 {
3793 Channel *c;
3794 int sock, r, success = 0, wildcard = 0, is_client;
3795 struct addrinfo hints, *ai, *aitop;
3796 const char *host, *addr;
3797 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
3798 in_port_t *lport_p;
3799
3800 is_client = (type == SSH_CHANNEL_PORT_LISTENER);
3801
3802 if (is_client && fwd->connect_path != NULL) {
3803 host = fwd->connect_path;
3804 } else {
3805 host = (type == SSH_CHANNEL_RPORT_LISTENER) ?
3806 fwd->listen_host : fwd->connect_host;
3807 if (host == NULL) {
3808 error("No forward host name.");
3809 return 0;
3810 }
3811 if (strlen(host) >= NI_MAXHOST) {
3812 error("Forward host name too long.");
3813 return 0;
3814 }
3815 }
3816
3817 /* Determine the bind address, cf. channel_fwd_bind_addr() comment */
3818 addr = channel_fwd_bind_addr(ssh, fwd->listen_host, &wildcard,
3819 is_client, fwd_opts);
3820 debug3_f("type %d wildcard %d addr %s", type, wildcard,
3821 (addr == NULL) ? "NULL" : addr);
3822
3823 /*
3824 * getaddrinfo returns a loopback address if the hostname is
3825 * set to NULL and hints.ai_flags is not AI_PASSIVE
3826 */
3827 memset(&hints, 0, sizeof(hints));
3828 hints.ai_family = ssh->chanctxt->IPv4or6;
3829 hints.ai_flags = wildcard ? AI_PASSIVE : 0;
3830 hints.ai_socktype = SOCK_STREAM;
3831 snprintf(strport, sizeof strport, "%d", fwd->listen_port);
3832 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) {
3833 if (addr == NULL) {
3834 /* This really shouldn't happen */
3835 ssh_packet_disconnect(ssh, "getaddrinfo: fatal error: %s",
3836 ssh_gai_strerror(r));
3837 } else {
3838 error_f("getaddrinfo(%.64s): %s", addr,
3839 ssh_gai_strerror(r));
3840 }
3841 return 0;
3842 }
3843 if (allocated_listen_port != NULL)
3844 *allocated_listen_port = 0;
3845 for (ai = aitop; ai; ai = ai->ai_next) {
3846 switch (ai->ai_family) {
3847 case AF_INET:
3848 lport_p = &((struct sockaddr_in *)ai->ai_addr)->
3849 sin_port;
3850 break;
3851 case AF_INET6:
3852 lport_p = &((struct sockaddr_in6 *)ai->ai_addr)->
3853 sin6_port;
3854 break;
3855 default:
3856 continue;
3857 }
3858 /*
3859 * If allocating a port for -R forwards, then use the
3860 * same port for all address families.
3861 */
3862 if (type == SSH_CHANNEL_RPORT_LISTENER &&
3863 fwd->listen_port == 0 && allocated_listen_port != NULL &&
3864 *allocated_listen_port > 0)
3865 *lport_p = htons(*allocated_listen_port);
3866
3867 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
3868 strport, sizeof(strport),
3869 NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
3870 error_f("getnameinfo failed");
3871 continue;
3872 }
3873 /* Create a port to listen for the host. */
3874 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
3875 if (sock == -1) {
3876 /* this is no error since kernel may not support ipv6 */
3877 verbose("socket [%s]:%s: %.100s", ntop, strport,
3878 strerror(errno));
3879 continue;
3880 }
3881
3882 set_reuseaddr(sock);
3883 if (ai->ai_family == AF_INET6)
3884 sock_set_v6only(sock);
3885
3886 debug("Local forwarding listening on %s port %s.",
3887 ntop, strport);
3888
3889 /* Bind the socket to the address. */
3890 if (bind(sock, ai->ai_addr, ai->ai_addrlen) == -1) {
3891 /*
3892 * address can be in if use ipv6 address is
3893 * already bound
3894 */
3895 if (!ai->ai_next)
3896 error("bind [%s]:%s: %.100s",
3897 ntop, strport, strerror(errno));
3898 else
3899 verbose("bind [%s]:%s: %.100s",
3900 ntop, strport, strerror(errno));
3901
3902 close(sock);
3903 continue;
3904 }
3905 /* Start listening for connections on the socket. */
3906 if (listen(sock, SSH_LISTEN_BACKLOG) == -1) {
3907 error("listen [%s]:%s: %.100s", ntop, strport,
3908 strerror(errno));
3909 close(sock);
3910 continue;
3911 }
3912
3913 /*
3914 * fwd->listen_port == 0 requests a dynamically allocated port -
3915 * record what we got.
3916 */
3917 if (type == SSH_CHANNEL_RPORT_LISTENER &&
3918 fwd->listen_port == 0 &&
3919 allocated_listen_port != NULL &&
3920 *allocated_listen_port == 0) {
3921 *allocated_listen_port = get_local_port(sock);
3922 debug("Allocated listen port %d",
3923 *allocated_listen_port);
3924 }
3925
3926 /* Allocate a channel number for the socket. */
3927 c = channel_new(ssh, "port-listener", type, sock, sock, -1,
3928 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
3929 0, "port listener", 1);
3930 c->path = xstrdup(host);
3931 c->host_port = fwd->connect_port;
3932 c->listening_addr = addr == NULL ? NULL : xstrdup(addr);
3933 if (fwd->listen_port == 0 && allocated_listen_port != NULL &&
3934 !(ssh->compat & SSH_BUG_DYNAMIC_RPORT))
3935 c->listening_port = *allocated_listen_port;
3936 else
3937 c->listening_port = fwd->listen_port;
3938 success = 1;
3939 }
3940 if (success == 0)
3941 error_f("cannot listen to port: %d", fwd->listen_port);
3942 freeaddrinfo(aitop);
3943 return success;
3944 }
3945
3946 static int
channel_setup_fwd_listener_streamlocal(struct ssh * ssh,int type,struct Forward * fwd,struct ForwardOptions * fwd_opts)3947 channel_setup_fwd_listener_streamlocal(struct ssh *ssh, int type,
3948 struct Forward *fwd, struct ForwardOptions *fwd_opts)
3949 {
3950 struct sockaddr_un sunaddr;
3951 const char *path;
3952 Channel *c;
3953 int port, sock;
3954 mode_t omask;
3955
3956 switch (type) {
3957 case SSH_CHANNEL_UNIX_LISTENER:
3958 if (fwd->connect_path != NULL) {
3959 if (strlen(fwd->connect_path) > sizeof(sunaddr.sun_path)) {
3960 error("Local connecting path too long: %s",
3961 fwd->connect_path);
3962 return 0;
3963 }
3964 path = fwd->connect_path;
3965 port = PORT_STREAMLOCAL;
3966 } else {
3967 if (fwd->connect_host == NULL) {
3968 error("No forward host name.");
3969 return 0;
3970 }
3971 if (strlen(fwd->connect_host) >= NI_MAXHOST) {
3972 error("Forward host name too long.");
3973 return 0;
3974 }
3975 path = fwd->connect_host;
3976 port = fwd->connect_port;
3977 }
3978 break;
3979 case SSH_CHANNEL_RUNIX_LISTENER:
3980 path = fwd->listen_path;
3981 port = PORT_STREAMLOCAL;
3982 break;
3983 default:
3984 error_f("unexpected channel type %d", type);
3985 return 0;
3986 }
3987
3988 if (fwd->listen_path == NULL) {
3989 error("No forward path name.");
3990 return 0;
3991 }
3992 if (strlen(fwd->listen_path) > sizeof(sunaddr.sun_path)) {
3993 error("Local listening path too long: %s", fwd->listen_path);
3994 return 0;
3995 }
3996
3997 debug3_f("type %d path %s", type, fwd->listen_path);
3998
3999 /* Start a Unix domain listener. */
4000 omask = umask(fwd_opts->streamlocal_bind_mask);
4001 sock = unix_listener(fwd->listen_path, SSH_LISTEN_BACKLOG,
4002 fwd_opts->streamlocal_bind_unlink);
4003 umask(omask);
4004 if (sock < 0)
4005 return 0;
4006
4007 debug("Local forwarding listening on path %s.", fwd->listen_path);
4008
4009 /* Allocate a channel number for the socket. */
4010 c = channel_new(ssh, "unix-listener", type, sock, sock, -1,
4011 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
4012 0, "unix listener", 1);
4013 c->path = xstrdup(path);
4014 c->host_port = port;
4015 c->listening_port = PORT_STREAMLOCAL;
4016 c->listening_addr = xstrdup(fwd->listen_path);
4017 return 1;
4018 }
4019
4020 static int
channel_cancel_rport_listener_tcpip(struct ssh * ssh,const char * host,u_short port)4021 channel_cancel_rport_listener_tcpip(struct ssh *ssh,
4022 const char *host, u_short port)
4023 {
4024 u_int i;
4025 int found = 0;
4026
4027 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) {
4028 Channel *c = ssh->chanctxt->channels[i];
4029 if (c == NULL || c->type != SSH_CHANNEL_RPORT_LISTENER)
4030 continue;
4031 if (strcmp(c->path, host) == 0 && c->listening_port == port) {
4032 debug2_f("close channel %d", i);
4033 channel_free(ssh, c);
4034 found = 1;
4035 }
4036 }
4037
4038 return found;
4039 }
4040
4041 static int
channel_cancel_rport_listener_streamlocal(struct ssh * ssh,const char * path)4042 channel_cancel_rport_listener_streamlocal(struct ssh *ssh, const char *path)
4043 {
4044 u_int i;
4045 int found = 0;
4046
4047 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) {
4048 Channel *c = ssh->chanctxt->channels[i];
4049 if (c == NULL || c->type != SSH_CHANNEL_RUNIX_LISTENER)
4050 continue;
4051 if (c->path == NULL)
4052 continue;
4053 if (strcmp(c->path, path) == 0) {
4054 debug2_f("close channel %d", i);
4055 channel_free(ssh, c);
4056 found = 1;
4057 }
4058 }
4059
4060 return found;
4061 }
4062
4063 int
channel_cancel_rport_listener(struct ssh * ssh,struct Forward * fwd)4064 channel_cancel_rport_listener(struct ssh *ssh, struct Forward *fwd)
4065 {
4066 if (fwd->listen_path != NULL) {
4067 return channel_cancel_rport_listener_streamlocal(ssh,
4068 fwd->listen_path);
4069 } else {
4070 return channel_cancel_rport_listener_tcpip(ssh,
4071 fwd->listen_host, fwd->listen_port);
4072 }
4073 }
4074
4075 static int
channel_cancel_lport_listener_tcpip(struct ssh * ssh,const char * lhost,u_short lport,int cport,struct ForwardOptions * fwd_opts)4076 channel_cancel_lport_listener_tcpip(struct ssh *ssh,
4077 const char *lhost, u_short lport, int cport,
4078 struct ForwardOptions *fwd_opts)
4079 {
4080 u_int i;
4081 int found = 0;
4082 const char *addr = channel_fwd_bind_addr(ssh, lhost, NULL, 1, fwd_opts);
4083
4084 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) {
4085 Channel *c = ssh->chanctxt->channels[i];
4086 if (c == NULL || c->type != SSH_CHANNEL_PORT_LISTENER)
4087 continue;
4088 if (c->listening_port != lport)
4089 continue;
4090 if (cport == CHANNEL_CANCEL_PORT_STATIC) {
4091 /* skip dynamic forwardings */
4092 if (c->host_port == 0)
4093 continue;
4094 } else {
4095 if (c->host_port != cport)
4096 continue;
4097 }
4098 if ((c->listening_addr == NULL && addr != NULL) ||
4099 (c->listening_addr != NULL && addr == NULL))
4100 continue;
4101 if (addr == NULL || strcmp(c->listening_addr, addr) == 0) {
4102 debug2_f("close channel %d", i);
4103 channel_free(ssh, c);
4104 found = 1;
4105 }
4106 }
4107
4108 return found;
4109 }
4110
4111 static int
channel_cancel_lport_listener_streamlocal(struct ssh * ssh,const char * path)4112 channel_cancel_lport_listener_streamlocal(struct ssh *ssh, const char *path)
4113 {
4114 u_int i;
4115 int found = 0;
4116
4117 if (path == NULL) {
4118 error_f("no path specified.");
4119 return 0;
4120 }
4121
4122 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) {
4123 Channel *c = ssh->chanctxt->channels[i];
4124 if (c == NULL || c->type != SSH_CHANNEL_UNIX_LISTENER)
4125 continue;
4126 if (c->listening_addr == NULL)
4127 continue;
4128 if (strcmp(c->listening_addr, path) == 0) {
4129 debug2_f("close channel %d", i);
4130 channel_free(ssh, c);
4131 found = 1;
4132 }
4133 }
4134
4135 return found;
4136 }
4137
4138 int
channel_cancel_lport_listener(struct ssh * ssh,struct Forward * fwd,int cport,struct ForwardOptions * fwd_opts)4139 channel_cancel_lport_listener(struct ssh *ssh,
4140 struct Forward *fwd, int cport, struct ForwardOptions *fwd_opts)
4141 {
4142 if (fwd->listen_path != NULL) {
4143 return channel_cancel_lport_listener_streamlocal(ssh,
4144 fwd->listen_path);
4145 } else {
4146 return channel_cancel_lport_listener_tcpip(ssh,
4147 fwd->listen_host, fwd->listen_port, cport, fwd_opts);
4148 }
4149 }
4150
4151 /* protocol local port fwd, used by ssh */
4152 int
channel_setup_local_fwd_listener(struct ssh * ssh,struct Forward * fwd,struct ForwardOptions * fwd_opts)4153 channel_setup_local_fwd_listener(struct ssh *ssh,
4154 struct Forward *fwd, struct ForwardOptions *fwd_opts)
4155 {
4156 if (fwd->listen_path != NULL) {
4157 return channel_setup_fwd_listener_streamlocal(ssh,
4158 SSH_CHANNEL_UNIX_LISTENER, fwd, fwd_opts);
4159 } else {
4160 return channel_setup_fwd_listener_tcpip(ssh,
4161 SSH_CHANNEL_PORT_LISTENER, fwd, NULL, fwd_opts);
4162 }
4163 }
4164
4165 /* Matches a remote forwarding permission against a requested forwarding */
4166 static int
remote_open_match(struct permission * allowed_open,struct Forward * fwd)4167 remote_open_match(struct permission *allowed_open, struct Forward *fwd)
4168 {
4169 int ret;
4170 char *lhost;
4171
4172 /* XXX add ACLs for streamlocal */
4173 if (fwd->listen_path != NULL)
4174 return 1;
4175
4176 if (fwd->listen_host == NULL || allowed_open->listen_host == NULL)
4177 return 0;
4178
4179 if (allowed_open->listen_port != FWD_PERMIT_ANY_PORT &&
4180 allowed_open->listen_port != fwd->listen_port)
4181 return 0;
4182
4183 /* Match hostnames case-insensitively */
4184 lhost = xstrdup(fwd->listen_host);
4185 lowercase(lhost);
4186 ret = match_pattern(lhost, allowed_open->listen_host);
4187 free(lhost);
4188
4189 return ret;
4190 }
4191
4192 /* Checks whether a requested remote forwarding is permitted */
4193 static int
check_rfwd_permission(struct ssh * ssh,struct Forward * fwd)4194 check_rfwd_permission(struct ssh *ssh, struct Forward *fwd)
4195 {
4196 struct ssh_channels *sc = ssh->chanctxt;
4197 struct permission_set *pset = &sc->remote_perms;
4198 u_int i, permit, permit_adm = 1;
4199 struct permission *perm;
4200
4201 /* XXX apply GatewayPorts override before checking? */
4202
4203 permit = pset->all_permitted;
4204 if (!permit) {
4205 for (i = 0; i < pset->num_permitted_user; i++) {
4206 perm = &pset->permitted_user[i];
4207 if (remote_open_match(perm, fwd)) {
4208 permit = 1;
4209 break;
4210 }
4211 }
4212 }
4213
4214 if (pset->num_permitted_admin > 0) {
4215 permit_adm = 0;
4216 for (i = 0; i < pset->num_permitted_admin; i++) {
4217 perm = &pset->permitted_admin[i];
4218 if (remote_open_match(perm, fwd)) {
4219 permit_adm = 1;
4220 break;
4221 }
4222 }
4223 }
4224
4225 return permit && permit_adm;
4226 }
4227
4228 /* protocol v2 remote port fwd, used by sshd */
4229 int
channel_setup_remote_fwd_listener(struct ssh * ssh,struct Forward * fwd,int * allocated_listen_port,struct ForwardOptions * fwd_opts)4230 channel_setup_remote_fwd_listener(struct ssh *ssh, struct Forward *fwd,
4231 int *allocated_listen_port, struct ForwardOptions *fwd_opts)
4232 {
4233 if (!check_rfwd_permission(ssh, fwd)) {
4234 ssh_packet_send_debug(ssh, "port forwarding refused");
4235 if (fwd->listen_path != NULL)
4236 /* XXX always allowed, see remote_open_match() */
4237 logit("Received request from %.100s port %d to "
4238 "remote forward to path \"%.100s\", "
4239 "but the request was denied.",
4240 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh),
4241 fwd->listen_path);
4242 else if(fwd->listen_host != NULL)
4243 logit("Received request from %.100s port %d to "
4244 "remote forward to host %.100s port %d, "
4245 "but the request was denied.",
4246 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh),
4247 fwd->listen_host, fwd->listen_port );
4248 else
4249 logit("Received request from %.100s port %d to remote "
4250 "forward, but the request was denied.",
4251 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
4252 return 0;
4253 }
4254 if (fwd->listen_path != NULL) {
4255 return channel_setup_fwd_listener_streamlocal(ssh,
4256 SSH_CHANNEL_RUNIX_LISTENER, fwd, fwd_opts);
4257 } else {
4258 return channel_setup_fwd_listener_tcpip(ssh,
4259 SSH_CHANNEL_RPORT_LISTENER, fwd, allocated_listen_port,
4260 fwd_opts);
4261 }
4262 }
4263
4264 /*
4265 * Translate the requested rfwd listen host to something usable for
4266 * this server.
4267 */
4268 static const char *
channel_rfwd_bind_host(const char * listen_host)4269 channel_rfwd_bind_host(const char *listen_host)
4270 {
4271 if (listen_host == NULL) {
4272 return "localhost";
4273 } else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0) {
4274 return "";
4275 } else
4276 return listen_host;
4277 }
4278
4279 /*
4280 * Initiate forwarding of connections to port "port" on remote host through
4281 * the secure channel to host:port from local side.
4282 * Returns handle (index) for updating the dynamic listen port with
4283 * channel_update_permission().
4284 */
4285 int
channel_request_remote_forwarding(struct ssh * ssh,struct Forward * fwd)4286 channel_request_remote_forwarding(struct ssh *ssh, struct Forward *fwd)
4287 {
4288 int r, success = 0, idx = -1;
4289 const char *host_to_connect, *listen_host, *listen_path;
4290 int port_to_connect, listen_port;
4291
4292 /* Send the forward request to the remote side. */
4293 if (fwd->listen_path != NULL) {
4294 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 ||
4295 (r = sshpkt_put_cstring(ssh,
4296 "streamlocal-forward@openssh.com")) != 0 ||
4297 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* want reply */
4298 (r = sshpkt_put_cstring(ssh, fwd->listen_path)) != 0 ||
4299 (r = sshpkt_send(ssh)) != 0 ||
4300 (r = ssh_packet_write_wait(ssh)) != 0)
4301 fatal_fr(r, "request streamlocal");
4302 } else {
4303 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 ||
4304 (r = sshpkt_put_cstring(ssh, "tcpip-forward")) != 0 ||
4305 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* want reply */
4306 (r = sshpkt_put_cstring(ssh,
4307 channel_rfwd_bind_host(fwd->listen_host))) != 0 ||
4308 (r = sshpkt_put_u32(ssh, fwd->listen_port)) != 0 ||
4309 (r = sshpkt_send(ssh)) != 0 ||
4310 (r = ssh_packet_write_wait(ssh)) != 0)
4311 fatal_fr(r, "request tcpip-forward");
4312 }
4313 /* Assume that server accepts the request */
4314 success = 1;
4315 if (success) {
4316 /* Record that connection to this host/port is permitted. */
4317 host_to_connect = listen_host = listen_path = NULL;
4318 port_to_connect = listen_port = 0;
4319 if (fwd->connect_path != NULL) {
4320 host_to_connect = fwd->connect_path;
4321 port_to_connect = PORT_STREAMLOCAL;
4322 } else {
4323 host_to_connect = fwd->connect_host;
4324 port_to_connect = fwd->connect_port;
4325 }
4326 if (fwd->listen_path != NULL) {
4327 listen_path = fwd->listen_path;
4328 listen_port = PORT_STREAMLOCAL;
4329 } else {
4330 listen_host = fwd->listen_host;
4331 listen_port = fwd->listen_port;
4332 }
4333 idx = permission_set_add(ssh, FORWARD_USER, FORWARD_LOCAL,
4334 host_to_connect, port_to_connect,
4335 listen_host, listen_path, listen_port, NULL);
4336 }
4337 return idx;
4338 }
4339
4340 static int
open_match(struct permission * allowed_open,const char * requestedhost,int requestedport)4341 open_match(struct permission *allowed_open, const char *requestedhost,
4342 int requestedport)
4343 {
4344 if (allowed_open->host_to_connect == NULL)
4345 return 0;
4346 if (allowed_open->port_to_connect != FWD_PERMIT_ANY_PORT &&
4347 allowed_open->port_to_connect != requestedport)
4348 return 0;
4349 if (strcmp(allowed_open->host_to_connect, FWD_PERMIT_ANY_HOST) != 0 &&
4350 strcmp(allowed_open->host_to_connect, requestedhost) != 0)
4351 return 0;
4352 return 1;
4353 }
4354
4355 /*
4356 * Note that in the listen host/port case
4357 * we don't support FWD_PERMIT_ANY_PORT and
4358 * need to translate between the configured-host (listen_host)
4359 * and what we've sent to the remote server (channel_rfwd_bind_host)
4360 */
4361 static int
open_listen_match_tcpip(struct permission * allowed_open,const char * requestedhost,u_short requestedport,int translate)4362 open_listen_match_tcpip(struct permission *allowed_open,
4363 const char *requestedhost, u_short requestedport, int translate)
4364 {
4365 const char *allowed_host;
4366
4367 if (allowed_open->host_to_connect == NULL)
4368 return 0;
4369 if (allowed_open->listen_port != requestedport)
4370 return 0;
4371 if (!translate && allowed_open->listen_host == NULL &&
4372 requestedhost == NULL)
4373 return 1;
4374 allowed_host = translate ?
4375 channel_rfwd_bind_host(allowed_open->listen_host) :
4376 allowed_open->listen_host;
4377 if (allowed_host == NULL || requestedhost == NULL ||
4378 strcmp(allowed_host, requestedhost) != 0)
4379 return 0;
4380 return 1;
4381 }
4382
4383 static int
open_listen_match_streamlocal(struct permission * allowed_open,const char * requestedpath)4384 open_listen_match_streamlocal(struct permission *allowed_open,
4385 const char *requestedpath)
4386 {
4387 if (allowed_open->host_to_connect == NULL)
4388 return 0;
4389 if (allowed_open->listen_port != PORT_STREAMLOCAL)
4390 return 0;
4391 if (allowed_open->listen_path == NULL ||
4392 strcmp(allowed_open->listen_path, requestedpath) != 0)
4393 return 0;
4394 return 1;
4395 }
4396
4397 /*
4398 * Request cancellation of remote forwarding of connection host:port from
4399 * local side.
4400 */
4401 static int
channel_request_rforward_cancel_tcpip(struct ssh * ssh,const char * host,u_short port)4402 channel_request_rforward_cancel_tcpip(struct ssh *ssh,
4403 const char *host, u_short port)
4404 {
4405 struct ssh_channels *sc = ssh->chanctxt;
4406 struct permission_set *pset = &sc->local_perms;
4407 int r;
4408 u_int i;
4409 struct permission *perm = NULL;
4410
4411 for (i = 0; i < pset->num_permitted_user; i++) {
4412 perm = &pset->permitted_user[i];
4413 if (open_listen_match_tcpip(perm, host, port, 0))
4414 break;
4415 perm = NULL;
4416 }
4417 if (perm == NULL) {
4418 debug_f("requested forward not found");
4419 return -1;
4420 }
4421 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 ||
4422 (r = sshpkt_put_cstring(ssh, "cancel-tcpip-forward")) != 0 ||
4423 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* want reply */
4424 (r = sshpkt_put_cstring(ssh, channel_rfwd_bind_host(host))) != 0 ||
4425 (r = sshpkt_put_u32(ssh, port)) != 0 ||
4426 (r = sshpkt_send(ssh)) != 0)
4427 fatal_fr(r, "send cancel");
4428
4429 fwd_perm_clear(perm); /* unregister */
4430
4431 return 0;
4432 }
4433
4434 /*
4435 * Request cancellation of remote forwarding of Unix domain socket
4436 * path from local side.
4437 */
4438 static int
channel_request_rforward_cancel_streamlocal(struct ssh * ssh,const char * path)4439 channel_request_rforward_cancel_streamlocal(struct ssh *ssh, const char *path)
4440 {
4441 struct ssh_channels *sc = ssh->chanctxt;
4442 struct permission_set *pset = &sc->local_perms;
4443 int r;
4444 u_int i;
4445 struct permission *perm = NULL;
4446
4447 for (i = 0; i < pset->num_permitted_user; i++) {
4448 perm = &pset->permitted_user[i];
4449 if (open_listen_match_streamlocal(perm, path))
4450 break;
4451 perm = NULL;
4452 }
4453 if (perm == NULL) {
4454 debug_f("requested forward not found");
4455 return -1;
4456 }
4457 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 ||
4458 (r = sshpkt_put_cstring(ssh,
4459 "cancel-streamlocal-forward@openssh.com")) != 0 ||
4460 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* want reply */
4461 (r = sshpkt_put_cstring(ssh, path)) != 0 ||
4462 (r = sshpkt_send(ssh)) != 0)
4463 fatal_fr(r, "send cancel");
4464
4465 fwd_perm_clear(perm); /* unregister */
4466
4467 return 0;
4468 }
4469
4470 /*
4471 * Request cancellation of remote forwarding of a connection from local side.
4472 */
4473 int
channel_request_rforward_cancel(struct ssh * ssh,struct Forward * fwd)4474 channel_request_rforward_cancel(struct ssh *ssh, struct Forward *fwd)
4475 {
4476 if (fwd->listen_path != NULL) {
4477 return channel_request_rforward_cancel_streamlocal(ssh,
4478 fwd->listen_path);
4479 } else {
4480 return channel_request_rforward_cancel_tcpip(ssh,
4481 fwd->listen_host,
4482 fwd->listen_port ? fwd->listen_port : fwd->allocated_port);
4483 }
4484 }
4485
4486 /*
4487 * Permits opening to any host/port if permitted_user[] is empty. This is
4488 * usually called by the server, because the user could connect to any port
4489 * anyway, and the server has no way to know but to trust the client anyway.
4490 */
4491 void
channel_permit_all(struct ssh * ssh,int where)4492 channel_permit_all(struct ssh *ssh, int where)
4493 {
4494 struct permission_set *pset = permission_set_get(ssh, where);
4495
4496 if (pset->num_permitted_user == 0)
4497 pset->all_permitted = 1;
4498 }
4499
4500 /*
4501 * Permit the specified host/port for forwarding.
4502 */
4503 void
channel_add_permission(struct ssh * ssh,int who,int where,char * host,int port)4504 channel_add_permission(struct ssh *ssh, int who, int where,
4505 char *host, int port)
4506 {
4507 int local = where == FORWARD_LOCAL;
4508 struct permission_set *pset = permission_set_get(ssh, where);
4509
4510 debug("allow %s forwarding to host %s port %d",
4511 fwd_ident(who, where), host, port);
4512 /*
4513 * Remote forwards set listen_host/port, local forwards set
4514 * host/port_to_connect.
4515 */
4516 permission_set_add(ssh, who, where,
4517 local ? host : 0, local ? port : 0,
4518 local ? NULL : host, NULL, local ? 0 : port, NULL);
4519 pset->all_permitted = 0;
4520 }
4521
4522 /*
4523 * Administratively disable forwarding.
4524 */
4525 void
channel_disable_admin(struct ssh * ssh,int where)4526 channel_disable_admin(struct ssh *ssh, int where)
4527 {
4528 channel_clear_permission(ssh, FORWARD_ADM, where);
4529 permission_set_add(ssh, FORWARD_ADM, where,
4530 NULL, 0, NULL, NULL, 0, NULL);
4531 }
4532
4533 /*
4534 * Clear a list of permitted opens.
4535 */
4536 void
channel_clear_permission(struct ssh * ssh,int who,int where)4537 channel_clear_permission(struct ssh *ssh, int who, int where)
4538 {
4539 struct permission **permp;
4540 u_int *npermp;
4541
4542 permission_set_get_array(ssh, who, where, &permp, &npermp);
4543 *permp = xrecallocarray(*permp, *npermp, 0, sizeof(**permp));
4544 *npermp = 0;
4545 }
4546
4547 /*
4548 * Update the listen port for a dynamic remote forward, after
4549 * the actual 'newport' has been allocated. If 'newport' < 0 is
4550 * passed then they entry will be invalidated.
4551 */
4552 void
channel_update_permission(struct ssh * ssh,int idx,int newport)4553 channel_update_permission(struct ssh *ssh, int idx, int newport)
4554 {
4555 struct permission_set *pset = &ssh->chanctxt->local_perms;
4556
4557 if (idx < 0 || (u_int)idx >= pset->num_permitted_user) {
4558 debug_f("index out of range: %d num_permitted_user %d",
4559 idx, pset->num_permitted_user);
4560 return;
4561 }
4562 debug("%s allowed port %d for forwarding to host %s port %d",
4563 newport > 0 ? "Updating" : "Removing",
4564 newport,
4565 pset->permitted_user[idx].host_to_connect,
4566 pset->permitted_user[idx].port_to_connect);
4567 if (newport <= 0)
4568 fwd_perm_clear(&pset->permitted_user[idx]);
4569 else {
4570 pset->permitted_user[idx].listen_port =
4571 (ssh->compat & SSH_BUG_DYNAMIC_RPORT) ? 0 : newport;
4572 }
4573 }
4574
4575 /* Try to start non-blocking connect to next host in cctx list */
4576 static int
connect_next(struct channel_connect * cctx)4577 connect_next(struct channel_connect *cctx)
4578 {
4579 int sock, saved_errno;
4580 struct sockaddr_un *sunaddr;
4581 char ntop[NI_MAXHOST];
4582 char strport[MAXIMUM(NI_MAXSERV, sizeof(sunaddr->sun_path))];
4583
4584 for (; cctx->ai; cctx->ai = cctx->ai->ai_next) {
4585 switch (cctx->ai->ai_family) {
4586 case AF_UNIX:
4587 /* unix:pathname instead of host:port */
4588 sunaddr = (struct sockaddr_un *)cctx->ai->ai_addr;
4589 strlcpy(ntop, "unix", sizeof(ntop));
4590 strlcpy(strport, sunaddr->sun_path, sizeof(strport));
4591 break;
4592 case AF_INET:
4593 case AF_INET6:
4594 if (getnameinfo(cctx->ai->ai_addr, cctx->ai->ai_addrlen,
4595 ntop, sizeof(ntop), strport, sizeof(strport),
4596 NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
4597 error_f("getnameinfo failed");
4598 continue;
4599 }
4600 break;
4601 default:
4602 continue;
4603 }
4604 debug_f("start for host %.100s ([%.100s]:%s)",
4605 cctx->host, ntop, strport);
4606 if ((sock = socket(cctx->ai->ai_family, cctx->ai->ai_socktype,
4607 cctx->ai->ai_protocol)) == -1) {
4608 if (cctx->ai->ai_next == NULL)
4609 error("socket: %.100s", strerror(errno));
4610 else
4611 verbose("socket: %.100s", strerror(errno));
4612 continue;
4613 }
4614 if (set_nonblock(sock) == -1)
4615 fatal_f("set_nonblock(%d)", sock);
4616 if (connect(sock, cctx->ai->ai_addr,
4617 cctx->ai->ai_addrlen) == -1 && errno != EINPROGRESS) {
4618 debug_f("host %.100s ([%.100s]:%s): %.100s",
4619 cctx->host, ntop, strport, strerror(errno));
4620 saved_errno = errno;
4621 close(sock);
4622 errno = saved_errno;
4623 continue; /* fail -- try next */
4624 }
4625 if (cctx->ai->ai_family != AF_UNIX)
4626 set_nodelay(sock);
4627 debug_f("connect host %.100s ([%.100s]:%s) in progress, fd=%d",
4628 cctx->host, ntop, strport, sock);
4629 cctx->ai = cctx->ai->ai_next;
4630 return sock;
4631 }
4632 return -1;
4633 }
4634
4635 static void
channel_connect_ctx_free(struct channel_connect * cctx)4636 channel_connect_ctx_free(struct channel_connect *cctx)
4637 {
4638 free(cctx->host);
4639 if (cctx->aitop) {
4640 if (cctx->aitop->ai_family == AF_UNIX)
4641 free(cctx->aitop);
4642 else
4643 freeaddrinfo(cctx->aitop);
4644 }
4645 memset(cctx, 0, sizeof(*cctx));
4646 }
4647
4648 /*
4649 * Return connecting socket to remote host:port or local socket path,
4650 * passing back the failure reason if appropriate.
4651 */
4652 static int
connect_to_helper(struct ssh * ssh,const char * name,int port,int socktype,char * ctype,char * rname,struct channel_connect * cctx,int * reason,const char ** errmsg)4653 connect_to_helper(struct ssh *ssh, const char *name, int port, int socktype,
4654 char *ctype, char *rname, struct channel_connect *cctx,
4655 int *reason, const char **errmsg)
4656 {
4657 struct addrinfo hints;
4658 int gaierr;
4659 int sock = -1;
4660 char strport[NI_MAXSERV];
4661
4662 if (port == PORT_STREAMLOCAL) {
4663 struct sockaddr_un *sunaddr;
4664 struct addrinfo *ai;
4665
4666 if (strlen(name) > sizeof(sunaddr->sun_path)) {
4667 error("%.100s: %.100s", name, strerror(ENAMETOOLONG));
4668 return -1;
4669 }
4670
4671 /*
4672 * Fake up a struct addrinfo for AF_UNIX connections.
4673 * channel_connect_ctx_free() must check ai_family
4674 * and use free() not freeaddirinfo() for AF_UNIX.
4675 */
4676 ai = xmalloc(sizeof(*ai) + sizeof(*sunaddr));
4677 memset(ai, 0, sizeof(*ai) + sizeof(*sunaddr));
4678 ai->ai_addr = (struct sockaddr *)(ai + 1);
4679 ai->ai_addrlen = sizeof(*sunaddr);
4680 ai->ai_family = AF_UNIX;
4681 ai->ai_socktype = socktype;
4682 ai->ai_protocol = PF_UNSPEC;
4683 sunaddr = (struct sockaddr_un *)ai->ai_addr;
4684 sunaddr->sun_family = AF_UNIX;
4685 strlcpy(sunaddr->sun_path, name, sizeof(sunaddr->sun_path));
4686 cctx->aitop = ai;
4687 } else {
4688 memset(&hints, 0, sizeof(hints));
4689 hints.ai_family = ssh->chanctxt->IPv4or6;
4690 hints.ai_socktype = socktype;
4691 snprintf(strport, sizeof strport, "%d", port);
4692 if ((gaierr = getaddrinfo(name, strport, &hints, &cctx->aitop))
4693 != 0) {
4694 if (errmsg != NULL)
4695 *errmsg = ssh_gai_strerror(gaierr);
4696 if (reason != NULL)
4697 *reason = SSH2_OPEN_CONNECT_FAILED;
4698 error("connect_to %.100s: unknown host (%s)", name,
4699 ssh_gai_strerror(gaierr));
4700 return -1;
4701 }
4702 }
4703
4704 cctx->host = xstrdup(name);
4705 cctx->port = port;
4706 cctx->ai = cctx->aitop;
4707
4708 if ((sock = connect_next(cctx)) == -1) {
4709 error("connect to %.100s port %d failed: %s",
4710 name, port, strerror(errno));
4711 return -1;
4712 }
4713
4714 return sock;
4715 }
4716
4717 /* Return CONNECTING channel to remote host:port or local socket path */
4718 static Channel *
connect_to(struct ssh * ssh,const char * host,int port,char * ctype,char * rname)4719 connect_to(struct ssh *ssh, const char *host, int port,
4720 char *ctype, char *rname)
4721 {
4722 struct channel_connect cctx;
4723 Channel *c;
4724 int sock;
4725
4726 memset(&cctx, 0, sizeof(cctx));
4727 sock = connect_to_helper(ssh, host, port, SOCK_STREAM, ctype, rname,
4728 &cctx, NULL, NULL);
4729 if (sock == -1) {
4730 channel_connect_ctx_free(&cctx);
4731 return NULL;
4732 }
4733 c = channel_new(ssh, ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1,
4734 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1);
4735 c->host_port = port;
4736 c->path = xstrdup(host);
4737 c->connect_ctx = cctx;
4738
4739 return c;
4740 }
4741
4742 /*
4743 * returns either the newly connected channel or the downstream channel
4744 * that needs to deal with this connection.
4745 */
4746 Channel *
channel_connect_by_listen_address(struct ssh * ssh,const char * listen_host,u_short listen_port,char * ctype,char * rname)4747 channel_connect_by_listen_address(struct ssh *ssh, const char *listen_host,
4748 u_short listen_port, char *ctype, char *rname)
4749 {
4750 struct ssh_channels *sc = ssh->chanctxt;
4751 struct permission_set *pset = &sc->local_perms;
4752 u_int i;
4753 struct permission *perm;
4754
4755 for (i = 0; i < pset->num_permitted_user; i++) {
4756 perm = &pset->permitted_user[i];
4757 if (open_listen_match_tcpip(perm,
4758 listen_host, listen_port, 1)) {
4759 if (perm->downstream)
4760 return perm->downstream;
4761 if (perm->port_to_connect == 0)
4762 return rdynamic_connect_prepare(ssh,
4763 ctype, rname);
4764 return connect_to(ssh,
4765 perm->host_to_connect, perm->port_to_connect,
4766 ctype, rname);
4767 }
4768 }
4769 error("WARNING: Server requests forwarding for unknown listen_port %d",
4770 listen_port);
4771 return NULL;
4772 }
4773
4774 Channel *
channel_connect_by_listen_path(struct ssh * ssh,const char * path,char * ctype,char * rname)4775 channel_connect_by_listen_path(struct ssh *ssh, const char *path,
4776 char *ctype, char *rname)
4777 {
4778 struct ssh_channels *sc = ssh->chanctxt;
4779 struct permission_set *pset = &sc->local_perms;
4780 u_int i;
4781 struct permission *perm;
4782
4783 for (i = 0; i < pset->num_permitted_user; i++) {
4784 perm = &pset->permitted_user[i];
4785 if (open_listen_match_streamlocal(perm, path)) {
4786 return connect_to(ssh,
4787 perm->host_to_connect, perm->port_to_connect,
4788 ctype, rname);
4789 }
4790 }
4791 error("WARNING: Server requests forwarding for unknown path %.100s",
4792 path);
4793 return NULL;
4794 }
4795
4796 /* Check if connecting to that port is permitted and connect. */
4797 Channel *
channel_connect_to_port(struct ssh * ssh,const char * host,u_short port,char * ctype,char * rname,int * reason,const char ** errmsg)4798 channel_connect_to_port(struct ssh *ssh, const char *host, u_short port,
4799 char *ctype, char *rname, int *reason, const char **errmsg)
4800 {
4801 struct ssh_channels *sc = ssh->chanctxt;
4802 struct permission_set *pset = &sc->local_perms;
4803 struct channel_connect cctx;
4804 Channel *c;
4805 u_int i, permit, permit_adm = 1;
4806 int sock;
4807 struct permission *perm;
4808
4809 permit = pset->all_permitted;
4810 if (!permit) {
4811 for (i = 0; i < pset->num_permitted_user; i++) {
4812 perm = &pset->permitted_user[i];
4813 if (open_match(perm, host, port)) {
4814 permit = 1;
4815 break;
4816 }
4817 }
4818 }
4819
4820 if (pset->num_permitted_admin > 0) {
4821 permit_adm = 0;
4822 for (i = 0; i < pset->num_permitted_admin; i++) {
4823 perm = &pset->permitted_admin[i];
4824 if (open_match(perm, host, port)) {
4825 permit_adm = 1;
4826 break;
4827 }
4828 }
4829 }
4830
4831 if (!permit || !permit_adm) {
4832 logit("Received request from %.100s port %d to connect to "
4833 "host %.100s port %d, but the request was denied.",
4834 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), host, port);
4835 if (reason != NULL)
4836 *reason = SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED;
4837 return NULL;
4838 }
4839
4840 memset(&cctx, 0, sizeof(cctx));
4841 sock = connect_to_helper(ssh, host, port, SOCK_STREAM, ctype, rname,
4842 &cctx, reason, errmsg);
4843 if (sock == -1) {
4844 channel_connect_ctx_free(&cctx);
4845 return NULL;
4846 }
4847
4848 c = channel_new(ssh, ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1,
4849 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1);
4850 c->host_port = port;
4851 c->path = xstrdup(host);
4852 c->connect_ctx = cctx;
4853
4854 return c;
4855 }
4856
4857 /* Check if connecting to that path is permitted and connect. */
4858 Channel *
channel_connect_to_path(struct ssh * ssh,const char * path,char * ctype,char * rname)4859 channel_connect_to_path(struct ssh *ssh, const char *path,
4860 char *ctype, char *rname)
4861 {
4862 struct ssh_channels *sc = ssh->chanctxt;
4863 struct permission_set *pset = &sc->local_perms;
4864 u_int i, permit, permit_adm = 1;
4865 struct permission *perm;
4866
4867 permit = pset->all_permitted;
4868 if (!permit) {
4869 for (i = 0; i < pset->num_permitted_user; i++) {
4870 perm = &pset->permitted_user[i];
4871 if (open_match(perm, path, PORT_STREAMLOCAL)) {
4872 permit = 1;
4873 break;
4874 }
4875 }
4876 }
4877
4878 if (pset->num_permitted_admin > 0) {
4879 permit_adm = 0;
4880 for (i = 0; i < pset->num_permitted_admin; i++) {
4881 perm = &pset->permitted_admin[i];
4882 if (open_match(perm, path, PORT_STREAMLOCAL)) {
4883 permit_adm = 1;
4884 break;
4885 }
4886 }
4887 }
4888
4889 if (!permit || !permit_adm) {
4890 logit("Received request to connect to path %.100s, "
4891 "but the request was denied.", path);
4892 return NULL;
4893 }
4894 return connect_to(ssh, path, PORT_STREAMLOCAL, ctype, rname);
4895 }
4896
4897 void
channel_send_window_changes(struct ssh * ssh)4898 channel_send_window_changes(struct ssh *ssh)
4899 {
4900 struct ssh_channels *sc = ssh->chanctxt;
4901 struct winsize ws;
4902 int r;
4903 u_int i;
4904
4905 for (i = 0; i < sc->channels_alloc; i++) {
4906 if (sc->channels[i] == NULL || !sc->channels[i]->client_tty ||
4907 sc->channels[i]->type != SSH_CHANNEL_OPEN)
4908 continue;
4909 if (ioctl(sc->channels[i]->rfd, TIOCGWINSZ, &ws) == -1)
4910 continue;
4911 channel_request_start(ssh, i, "window-change", 0);
4912 if ((r = sshpkt_put_u32(ssh, (u_int)ws.ws_col)) != 0 ||
4913 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_row)) != 0 ||
4914 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_xpixel)) != 0 ||
4915 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_ypixel)) != 0 ||
4916 (r = sshpkt_send(ssh)) != 0)
4917 fatal_fr(r, "channel %u; send window-change", i);
4918 }
4919 }
4920
4921 /* Return RDYNAMIC_OPEN channel: channel allows SOCKS, but is not connected */
4922 static Channel *
rdynamic_connect_prepare(struct ssh * ssh,char * ctype,char * rname)4923 rdynamic_connect_prepare(struct ssh *ssh, char *ctype, char *rname)
4924 {
4925 Channel *c;
4926 int r;
4927
4928 c = channel_new(ssh, ctype, SSH_CHANNEL_RDYNAMIC_OPEN, -1, -1, -1,
4929 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1);
4930 c->host_port = 0;
4931 c->path = NULL;
4932
4933 /*
4934 * We need to open the channel before we have a FD,
4935 * so that we can get SOCKS header from peer.
4936 */
4937 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 ||
4938 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 ||
4939 (r = sshpkt_put_u32(ssh, c->self)) != 0 ||
4940 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 ||
4941 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0)
4942 fatal_fr(r, "channel %i; confirm", c->self);
4943 return c;
4944 }
4945
4946 /* Return CONNECTING socket to remote host:port or local socket path */
4947 static int
rdynamic_connect_finish(struct ssh * ssh,Channel * c)4948 rdynamic_connect_finish(struct ssh *ssh, Channel *c)
4949 {
4950 struct ssh_channels *sc = ssh->chanctxt;
4951 struct permission_set *pset = &sc->local_perms;
4952 struct permission *perm;
4953 struct channel_connect cctx;
4954 u_int i, permit_adm = 1;
4955 int sock;
4956
4957 if (pset->num_permitted_admin > 0) {
4958 permit_adm = 0;
4959 for (i = 0; i < pset->num_permitted_admin; i++) {
4960 perm = &pset->permitted_admin[i];
4961 if (open_match(perm, c->path, c->host_port)) {
4962 permit_adm = 1;
4963 break;
4964 }
4965 }
4966 }
4967 if (!permit_adm) {
4968 debug_f("requested forward not permitted");
4969 return -1;
4970 }
4971
4972 memset(&cctx, 0, sizeof(cctx));
4973 sock = connect_to_helper(ssh, c->path, c->host_port, SOCK_STREAM, NULL,
4974 NULL, &cctx, NULL, NULL);
4975 if (sock == -1)
4976 channel_connect_ctx_free(&cctx);
4977 else {
4978 /* similar to SSH_CHANNEL_CONNECTING but we've already sent the open */
4979 c->type = SSH_CHANNEL_RDYNAMIC_FINISH;
4980 c->connect_ctx = cctx;
4981 channel_register_fds(ssh, c, sock, sock, -1, 0, 1, 0);
4982 }
4983 return sock;
4984 }
4985
4986 /* -- X11 forwarding */
4987
4988 /*
4989 * Creates an internet domain socket for listening for X11 connections.
4990 * Returns 0 and a suitable display number for the DISPLAY variable
4991 * stored in display_numberp , or -1 if an error occurs.
4992 */
4993 int
x11_create_display_inet(struct ssh * ssh,int x11_display_offset,int x11_use_localhost,int single_connection,u_int * display_numberp,int ** chanids)4994 x11_create_display_inet(struct ssh *ssh, int x11_display_offset,
4995 int x11_use_localhost, int single_connection,
4996 u_int *display_numberp, int **chanids)
4997 {
4998 Channel *nc = NULL;
4999 int display_number, sock;
5000 u_short port;
5001 struct addrinfo hints, *ai, *aitop;
5002 char strport[NI_MAXSERV];
5003 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
5004
5005 if (chanids == NULL)
5006 return -1;
5007
5008 for (display_number = x11_display_offset;
5009 display_number < MAX_DISPLAYS;
5010 display_number++) {
5011 port = 6000 + display_number;
5012 memset(&hints, 0, sizeof(hints));
5013 hints.ai_family = ssh->chanctxt->IPv4or6;
5014 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE;
5015 hints.ai_socktype = SOCK_STREAM;
5016 snprintf(strport, sizeof strport, "%d", port);
5017 if ((gaierr = getaddrinfo(NULL, strport,
5018 &hints, &aitop)) != 0) {
5019 error("getaddrinfo: %.100s", ssh_gai_strerror(gaierr));
5020 return -1;
5021 }
5022 for (ai = aitop; ai; ai = ai->ai_next) {
5023 if (ai->ai_family != AF_INET &&
5024 ai->ai_family != AF_INET6)
5025 continue;
5026 sock = socket(ai->ai_family, ai->ai_socktype,
5027 ai->ai_protocol);
5028 if (sock == -1) {
5029 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)
5030 #ifdef EPFNOSUPPORT
5031 && (errno != EPFNOSUPPORT)
5032 #endif
5033 ) {
5034 error("socket: %.100s", strerror(errno));
5035 freeaddrinfo(aitop);
5036 return -1;
5037 } else {
5038 debug("x11_create_display_inet: Socket family %d not supported",
5039 ai->ai_family);
5040 continue;
5041 }
5042 }
5043 if (ai->ai_family == AF_INET6)
5044 sock_set_v6only(sock);
5045 if (x11_use_localhost)
5046 set_reuseaddr(sock);
5047 if (bind(sock, ai->ai_addr, ai->ai_addrlen) == -1) {
5048 debug2_f("bind port %d: %.100s", port,
5049 strerror(errno));
5050 close(sock);
5051 for (n = 0; n < num_socks; n++)
5052 close(socks[n]);
5053 num_socks = 0;
5054 break;
5055 }
5056 socks[num_socks++] = sock;
5057 if (num_socks == NUM_SOCKS)
5058 break;
5059 }
5060 freeaddrinfo(aitop);
5061 if (num_socks > 0)
5062 break;
5063 }
5064 if (display_number >= MAX_DISPLAYS) {
5065 error("Failed to allocate internet-domain X11 display socket.");
5066 return -1;
5067 }
5068 /* Start listening for connections on the socket. */
5069 for (n = 0; n < num_socks; n++) {
5070 sock = socks[n];
5071 if (listen(sock, SSH_LISTEN_BACKLOG) == -1) {
5072 error("listen: %.100s", strerror(errno));
5073 close(sock);
5074 return -1;
5075 }
5076 }
5077
5078 /* Allocate a channel for each socket. */
5079 *chanids = xcalloc(num_socks + 1, sizeof(**chanids));
5080 for (n = 0; n < num_socks; n++) {
5081 sock = socks[n];
5082 nc = channel_new(ssh, "x11-listener",
5083 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
5084 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
5085 0, "X11 inet listener", 1);
5086 nc->single_connection = single_connection;
5087 (*chanids)[n] = nc->self;
5088 }
5089 (*chanids)[n] = -1;
5090
5091 /* Return the display number for the DISPLAY environment variable. */
5092 *display_numberp = display_number;
5093 return 0;
5094 }
5095
5096 static int
connect_local_xsocket_path(const char * pathname)5097 connect_local_xsocket_path(const char *pathname)
5098 {
5099 int sock;
5100 struct sockaddr_un addr;
5101
5102 sock = socket(AF_UNIX, SOCK_STREAM, 0);
5103 if (sock == -1) {
5104 error("socket: %.100s", strerror(errno));
5105 return -1;
5106 }
5107 memset(&addr, 0, sizeof(addr));
5108 addr.sun_family = AF_UNIX;
5109 strlcpy(addr.sun_path, pathname, sizeof addr.sun_path);
5110 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0)
5111 return sock;
5112 close(sock);
5113 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
5114 return -1;
5115 }
5116
5117 static int
connect_local_xsocket(u_int dnr)5118 connect_local_xsocket(u_int dnr)
5119 {
5120 char buf[1024];
5121 snprintf(buf, sizeof buf, _PATH_UNIX_X, dnr);
5122 return connect_local_xsocket_path(buf);
5123 }
5124
5125 #ifdef __APPLE__
5126 static int
is_path_to_xsocket(const char * display,char * path,size_t pathlen)5127 is_path_to_xsocket(const char *display, char *path, size_t pathlen)
5128 {
5129 struct stat sbuf;
5130
5131 if (strlcpy(path, display, pathlen) >= pathlen) {
5132 error("%s: display path too long", __func__);
5133 return 0;
5134 }
5135 if (display[0] != '/')
5136 return 0;
5137 if (stat(path, &sbuf) == 0) {
5138 return 1;
5139 } else {
5140 char *dot = strrchr(path, '.');
5141 if (dot != NULL) {
5142 *dot = '\0';
5143 if (stat(path, &sbuf) == 0) {
5144 return 1;
5145 }
5146 }
5147 }
5148 return 0;
5149 }
5150 #endif
5151
5152 int
x11_connect_display(struct ssh * ssh)5153 x11_connect_display(struct ssh *ssh)
5154 {
5155 u_int display_number;
5156 const char *display;
5157 char buf[1024], *cp;
5158 struct addrinfo hints, *ai, *aitop;
5159 char strport[NI_MAXSERV];
5160 int gaierr, sock = 0;
5161
5162 /* Try to open a socket for the local X server. */
5163 display = getenv("DISPLAY");
5164 if (!display) {
5165 error("DISPLAY not set.");
5166 return -1;
5167 }
5168 /*
5169 * Now we decode the value of the DISPLAY variable and make a
5170 * connection to the real X server.
5171 */
5172
5173 #ifdef __APPLE__
5174 /* Check if display is a path to a socket (as set by launchd). */
5175 {
5176 char path[PATH_MAX];
5177
5178 if (is_path_to_xsocket(display, path, sizeof(path))) {
5179 debug("x11_connect_display: $DISPLAY is launchd");
5180
5181 /* Create a socket. */
5182 sock = connect_local_xsocket_path(path);
5183 if (sock < 0)
5184 return -1;
5185
5186 /* OK, we now have a connection to the display. */
5187 return sock;
5188 }
5189 }
5190 #endif
5191 /*
5192 * Check if it is a unix domain socket. Unix domain displays are in
5193 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
5194 */
5195 if (strncmp(display, "unix:", 5) == 0 ||
5196 display[0] == ':') {
5197 /* Connect to the unix domain socket. */
5198 if (sscanf(strrchr(display, ':') + 1, "%u",
5199 &display_number) != 1) {
5200 error("Could not parse display number from DISPLAY: "
5201 "%.100s", display);
5202 return -1;
5203 }
5204 /* Create a socket. */
5205 sock = connect_local_xsocket(display_number);
5206 if (sock < 0)
5207 return -1;
5208
5209 /* OK, we now have a connection to the display. */
5210 return sock;
5211 }
5212 /*
5213 * Connect to an inet socket. The DISPLAY value is supposedly
5214 * hostname:d[.s], where hostname may also be numeric IP address.
5215 */
5216 strlcpy(buf, display, sizeof(buf));
5217 cp = strchr(buf, ':');
5218 if (!cp) {
5219 error("Could not find ':' in DISPLAY: %.100s", display);
5220 return -1;
5221 }
5222 *cp = 0;
5223 /*
5224 * buf now contains the host name. But first we parse the
5225 * display number.
5226 */
5227 if (sscanf(cp + 1, "%u", &display_number) != 1) {
5228 error("Could not parse display number from DISPLAY: %.100s",
5229 display);
5230 return -1;
5231 }
5232
5233 /* Look up the host address */
5234 memset(&hints, 0, sizeof(hints));
5235 hints.ai_family = ssh->chanctxt->IPv4or6;
5236 hints.ai_socktype = SOCK_STREAM;
5237 snprintf(strport, sizeof strport, "%u", 6000 + display_number);
5238 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
5239 error("%.100s: unknown host. (%s)", buf,
5240 ssh_gai_strerror(gaierr));
5241 return -1;
5242 }
5243 for (ai = aitop; ai; ai = ai->ai_next) {
5244 /* Create a socket. */
5245 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
5246 if (sock == -1) {
5247 debug2("socket: %.100s", strerror(errno));
5248 continue;
5249 }
5250 /* Connect it to the display. */
5251 if (connect(sock, ai->ai_addr, ai->ai_addrlen) == -1) {
5252 debug2("connect %.100s port %u: %.100s", buf,
5253 6000 + display_number, strerror(errno));
5254 close(sock);
5255 continue;
5256 }
5257 /* Success */
5258 break;
5259 }
5260 freeaddrinfo(aitop);
5261 if (!ai) {
5262 error("connect %.100s port %u: %.100s", buf,
5263 6000 + display_number, strerror(errno));
5264 return -1;
5265 }
5266 set_nodelay(sock);
5267 return sock;
5268 }
5269
5270 /*
5271 * Requests forwarding of X11 connections, generates fake authentication
5272 * data, and enables authentication spoofing.
5273 * This should be called in the client only.
5274 */
5275 void
x11_request_forwarding_with_spoofing(struct ssh * ssh,int client_session_id,const char * disp,const char * proto,const char * data,int want_reply)5276 x11_request_forwarding_with_spoofing(struct ssh *ssh, int client_session_id,
5277 const char *disp, const char *proto, const char *data, int want_reply)
5278 {
5279 struct ssh_channels *sc = ssh->chanctxt;
5280 u_int data_len = (u_int) strlen(data) / 2;
5281 u_int i, value;
5282 const char *cp;
5283 char *new_data;
5284 int r, screen_number;
5285
5286 if (sc->x11_saved_display == NULL)
5287 sc->x11_saved_display = xstrdup(disp);
5288 else if (strcmp(disp, sc->x11_saved_display) != 0) {
5289 error("x11_request_forwarding_with_spoofing: different "
5290 "$DISPLAY already forwarded");
5291 return;
5292 }
5293
5294 cp = strchr(disp, ':');
5295 if (cp)
5296 cp = strchr(cp, '.');
5297 if (cp)
5298 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL);
5299 else
5300 screen_number = 0;
5301
5302 if (sc->x11_saved_proto == NULL) {
5303 /* Save protocol name. */
5304 sc->x11_saved_proto = xstrdup(proto);
5305
5306 /* Extract real authentication data. */
5307 sc->x11_saved_data = xmalloc(data_len);
5308 for (i = 0; i < data_len; i++) {
5309 if (sscanf(data + 2 * i, "%2x", &value) != 1) {
5310 fatal("x11_request_forwarding: bad "
5311 "authentication data: %.100s", data);
5312 }
5313 sc->x11_saved_data[i] = value;
5314 }
5315 sc->x11_saved_data_len = data_len;
5316
5317 /* Generate fake data of the same length. */
5318 sc->x11_fake_data = xmalloc(data_len);
5319 arc4random_buf(sc->x11_fake_data, data_len);
5320 sc->x11_fake_data_len = data_len;
5321 }
5322
5323 /* Convert the fake data into hex. */
5324 new_data = tohex(sc->x11_fake_data, data_len);
5325
5326 /* Send the request packet. */
5327 channel_request_start(ssh, client_session_id, "x11-req", want_reply);
5328 if ((r = sshpkt_put_u8(ssh, 0)) != 0 || /* bool: single connection */
5329 (r = sshpkt_put_cstring(ssh, proto)) != 0 ||
5330 (r = sshpkt_put_cstring(ssh, new_data)) != 0 ||
5331 (r = sshpkt_put_u32(ssh, screen_number)) != 0 ||
5332 (r = sshpkt_send(ssh)) != 0 ||
5333 (r = ssh_packet_write_wait(ssh)) != 0)
5334 fatal_fr(r, "send x11-req");
5335 free(new_data);
5336 }
5337