1 /* $OpenBSD: channels.c,v 1.398 2020/04/25 06:59:36 dtucker 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 #include <stdarg.h>
61 #ifdef HAVE_STDINT_H
62 # include <stdint.h>
63 #endif
64 #include <stdio.h>
65 #include <stdlib.h>
66 #include <string.h>
67 #include <termios.h>
68 #include <unistd.h>
69
70 #include "openbsd-compat/sys-queue.h"
71 #include "xmalloc.h"
72 #include "ssh.h"
73 #include "ssh2.h"
74 #include "ssherr.h"
75 #include "sshbuf.h"
76 #include "packet.h"
77 #include "log.h"
78 #include "misc.h"
79 #include "channels.h"
80 #include "compat.h"
81 #include "canohost.h"
82 #include "sshkey.h"
83 #include "authfd.h"
84 #include "pathnames.h"
85 #include "match.h"
86
87 /* -- agent forwarding */
88 #define NUM_SOCKS 10
89
90 /* -- tcp forwarding */
91 /* special-case port number meaning allow any port */
92 #define FWD_PERMIT_ANY_PORT 0
93
94 /* special-case wildcard meaning allow any host */
95 #define FWD_PERMIT_ANY_HOST "*"
96
97 /* -- X11 forwarding */
98 /* Maximum number of fake X11 displays to try. */
99 #define MAX_DISPLAYS 1000
100
101 /* Per-channel callback for pre/post select() actions */
102 typedef void chan_fn(struct ssh *, Channel *c,
103 fd_set *readset, fd_set *writeset);
104
105 /*
106 * Data structure for storing which hosts are permitted for forward requests.
107 * The local sides of any remote forwards are stored in this array to prevent
108 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local
109 * network (which might be behind a firewall).
110 */
111 /* XXX: streamlocal wants a path instead of host:port */
112 /* Overload host_to_connect; we could just make this match Forward */
113 /* XXX - can we use listen_host instead of listen_path? */
114 struct permission {
115 char *host_to_connect; /* Connect to 'host'. */
116 int port_to_connect; /* Connect to 'port'. */
117 char *listen_host; /* Remote side should listen address. */
118 char *listen_path; /* Remote side should listen path. */
119 int listen_port; /* Remote side should listen port. */
120 Channel *downstream; /* Downstream mux*/
121 };
122
123 /*
124 * Stores the forwarding permission state for a single direction (local or
125 * remote).
126 */
127 struct permission_set {
128 /*
129 * List of all local permitted host/port pairs to allow for the
130 * user.
131 */
132 u_int num_permitted_user;
133 struct permission *permitted_user;
134
135 /*
136 * List of all permitted host/port pairs to allow for the admin.
137 */
138 u_int num_permitted_admin;
139 struct permission *permitted_admin;
140
141 /*
142 * If this is true, all opens/listens are permitted. This is the
143 * case on the server on which we have to trust the client anyway,
144 * and the user could do anything after logging in.
145 */
146 int all_permitted;
147 };
148
149 /* Master structure for channels state */
150 struct ssh_channels {
151 /*
152 * Pointer to an array containing all allocated channels. The array
153 * is dynamically extended as needed.
154 */
155 Channel **channels;
156
157 /*
158 * Size of the channel array. All slots of the array must always be
159 * initialized (at least the type field); unused slots set to NULL
160 */
161 u_int channels_alloc;
162
163 /*
164 * Maximum file descriptor value used in any of the channels. This is
165 * updated in channel_new.
166 */
167 int channel_max_fd;
168
169 /*
170 * 'channel_pre*' are called just before select() to add any bits
171 * relevant to channels in the select bitmasks.
172 *
173 * 'channel_post*': perform any appropriate operations for
174 * channels which have events pending.
175 */
176 chan_fn **channel_pre;
177 chan_fn **channel_post;
178
179 /* -- tcp forwarding */
180 struct permission_set local_perms;
181 struct permission_set remote_perms;
182
183 /* -- X11 forwarding */
184
185 /* Saved X11 local (client) display. */
186 char *x11_saved_display;
187
188 /* Saved X11 authentication protocol name. */
189 char *x11_saved_proto;
190
191 /* Saved X11 authentication data. This is the real data. */
192 char *x11_saved_data;
193 u_int x11_saved_data_len;
194
195 /* Deadline after which all X11 connections are refused */
196 u_int x11_refuse_time;
197
198 /*
199 * Fake X11 authentication data. This is what the server will be
200 * sending us; we should replace any occurrences of this by the
201 * real data.
202 */
203 u_char *x11_fake_data;
204 u_int x11_fake_data_len;
205
206 /* AF_UNSPEC or AF_INET or AF_INET6 */
207 int IPv4or6;
208 };
209
210 /* helper */
211 static void port_open_helper(struct ssh *ssh, Channel *c, char *rtype);
212 static const char *channel_rfwd_bind_host(const char *listen_host);
213
214 /* non-blocking connect helpers */
215 static int connect_next(struct channel_connect *);
216 static void channel_connect_ctx_free(struct channel_connect *);
217 static Channel *rdynamic_connect_prepare(struct ssh *, char *, char *);
218 static int rdynamic_connect_finish(struct ssh *, Channel *);
219
220 /* Setup helper */
221 static void channel_handler_init(struct ssh_channels *sc);
222
223 /* -- channel core */
224
225 void
channel_init_channels(struct ssh * ssh)226 channel_init_channels(struct ssh *ssh)
227 {
228 struct ssh_channels *sc;
229
230 if ((sc = calloc(1, sizeof(*sc))) == NULL)
231 fatal("%s: allocation failed", __func__);
232 sc->channels_alloc = 10;
233 sc->channels = xcalloc(sc->channels_alloc, sizeof(*sc->channels));
234 sc->IPv4or6 = AF_UNSPEC;
235 channel_handler_init(sc);
236
237 ssh->chanctxt = sc;
238 }
239
240 Channel *
channel_by_id(struct ssh * ssh,int id)241 channel_by_id(struct ssh *ssh, int id)
242 {
243 Channel *c;
244
245 if (id < 0 || (u_int)id >= ssh->chanctxt->channels_alloc) {
246 logit("%s: %d: bad id", __func__, id);
247 return NULL;
248 }
249 c = ssh->chanctxt->channels[id];
250 if (c == NULL) {
251 logit("%s: %d: bad id: channel free", __func__, id);
252 return NULL;
253 }
254 return c;
255 }
256
257 Channel *
channel_by_remote_id(struct ssh * ssh,u_int remote_id)258 channel_by_remote_id(struct ssh *ssh, u_int remote_id)
259 {
260 Channel *c;
261 u_int i;
262
263 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) {
264 c = ssh->chanctxt->channels[i];
265 if (c != NULL && c->have_remote_id && c->remote_id == remote_id)
266 return c;
267 }
268 return NULL;
269 }
270
271 /*
272 * Returns the channel if it is allowed to receive protocol messages.
273 * Private channels, like listening sockets, may not receive messages.
274 */
275 Channel *
channel_lookup(struct ssh * ssh,int id)276 channel_lookup(struct ssh *ssh, int id)
277 {
278 Channel *c;
279
280 if ((c = channel_by_id(ssh, id)) == NULL)
281 return NULL;
282
283 switch (c->type) {
284 case SSH_CHANNEL_X11_OPEN:
285 case SSH_CHANNEL_LARVAL:
286 case SSH_CHANNEL_CONNECTING:
287 case SSH_CHANNEL_DYNAMIC:
288 case SSH_CHANNEL_RDYNAMIC_OPEN:
289 case SSH_CHANNEL_RDYNAMIC_FINISH:
290 case SSH_CHANNEL_OPENING:
291 case SSH_CHANNEL_OPEN:
292 case SSH_CHANNEL_ABANDONED:
293 case SSH_CHANNEL_MUX_PROXY:
294 return c;
295 }
296 logit("Non-public channel %d, type %d.", id, c->type);
297 return NULL;
298 }
299
300 /*
301 * Register filedescriptors for a channel, used when allocating a channel or
302 * when the channel consumer/producer is ready, e.g. shell exec'd
303 */
304 static void
channel_register_fds(struct ssh * ssh,Channel * c,int rfd,int wfd,int efd,int extusage,int nonblock,int is_tty)305 channel_register_fds(struct ssh *ssh, Channel *c, int rfd, int wfd, int efd,
306 int extusage, int nonblock, int is_tty)
307 {
308 struct ssh_channels *sc = ssh->chanctxt;
309
310 /* Update the maximum file descriptor value. */
311 sc->channel_max_fd = MAXIMUM(sc->channel_max_fd, rfd);
312 sc->channel_max_fd = MAXIMUM(sc->channel_max_fd, wfd);
313 sc->channel_max_fd = MAXIMUM(sc->channel_max_fd, efd);
314
315 if (rfd != -1)
316 fcntl(rfd, F_SETFD, FD_CLOEXEC);
317 if (wfd != -1 && wfd != rfd)
318 fcntl(wfd, F_SETFD, FD_CLOEXEC);
319 if (efd != -1 && efd != rfd && efd != wfd)
320 fcntl(efd, F_SETFD, FD_CLOEXEC);
321
322 c->rfd = rfd;
323 c->wfd = wfd;
324 c->sock = (rfd == wfd) ? rfd : -1;
325 c->efd = efd;
326 c->extended_usage = extusage;
327
328 if ((c->isatty = is_tty) != 0)
329 debug2("channel %d: rfd %d isatty", c->self, c->rfd);
330 #ifdef _AIX
331 /* XXX: Later AIX versions can't push as much data to tty */
332 c->wfd_isatty = is_tty || isatty(c->wfd);
333 #endif
334
335 /* enable nonblocking mode */
336 if (nonblock) {
337 if (rfd != -1)
338 set_nonblock(rfd);
339 if (wfd != -1)
340 set_nonblock(wfd);
341 if (efd != -1)
342 set_nonblock(efd);
343 }
344 }
345
346 /*
347 * Allocate a new channel object and set its type and socket. This will cause
348 * remote_name to be freed.
349 */
350 Channel *
channel_new(struct ssh * ssh,char * ctype,int type,int rfd,int wfd,int efd,u_int window,u_int maxpack,int extusage,char * remote_name,int nonblock)351 channel_new(struct ssh *ssh, char *ctype, int type, int rfd, int wfd, int efd,
352 u_int window, u_int maxpack, int extusage, char *remote_name, int nonblock)
353 {
354 struct ssh_channels *sc = ssh->chanctxt;
355 u_int i, found;
356 Channel *c;
357
358 /* Try to find a free slot where to put the new channel. */
359 for (i = 0; i < sc->channels_alloc; i++) {
360 if (sc->channels[i] == NULL) {
361 /* Found a free slot. */
362 found = i;
363 break;
364 }
365 }
366 if (i >= sc->channels_alloc) {
367 /*
368 * There are no free slots. Take last+1 slot and expand
369 * the array.
370 */
371 found = sc->channels_alloc;
372 if (sc->channels_alloc > CHANNELS_MAX_CHANNELS)
373 fatal("%s: internal error: channels_alloc %d too big",
374 __func__, sc->channels_alloc);
375 sc->channels = xrecallocarray(sc->channels, sc->channels_alloc,
376 sc->channels_alloc + 10, sizeof(*sc->channels));
377 sc->channels_alloc += 10;
378 debug2("channel: expanding %d", sc->channels_alloc);
379 }
380 /* Initialize and return new channel. */
381 c = sc->channels[found] = xcalloc(1, sizeof(Channel));
382 if ((c->input = sshbuf_new()) == NULL ||
383 (c->output = sshbuf_new()) == NULL ||
384 (c->extended = sshbuf_new()) == NULL)
385 fatal("%s: sshbuf_new failed", __func__);
386 c->ostate = CHAN_OUTPUT_OPEN;
387 c->istate = CHAN_INPUT_OPEN;
388 channel_register_fds(ssh, c, rfd, wfd, efd, extusage, nonblock, 0);
389 c->self = found;
390 c->type = type;
391 c->ctype = ctype;
392 c->local_window = window;
393 c->local_window_max = window;
394 c->local_maxpacket = maxpack;
395 c->remote_name = xstrdup(remote_name);
396 c->ctl_chan = -1;
397 c->delayed = 1; /* prevent call to channel_post handler */
398 TAILQ_INIT(&c->status_confirms);
399 debug("channel %d: new [%s]", found, remote_name);
400 return c;
401 }
402
403 static void
channel_find_maxfd(struct ssh_channels * sc)404 channel_find_maxfd(struct ssh_channels *sc)
405 {
406 u_int i;
407 int max = 0;
408 Channel *c;
409
410 for (i = 0; i < sc->channels_alloc; i++) {
411 c = sc->channels[i];
412 if (c != NULL) {
413 max = MAXIMUM(max, c->rfd);
414 max = MAXIMUM(max, c->wfd);
415 max = MAXIMUM(max, c->efd);
416 }
417 }
418 sc->channel_max_fd = max;
419 }
420
421 int
channel_close_fd(struct ssh * ssh,int * fdp)422 channel_close_fd(struct ssh *ssh, int *fdp)
423 {
424 struct ssh_channels *sc = ssh->chanctxt;
425 int ret = 0, fd = *fdp;
426
427 if (fd != -1) {
428 ret = close(fd);
429 *fdp = -1;
430 if (fd == sc->channel_max_fd)
431 channel_find_maxfd(sc);
432 }
433 return ret;
434 }
435
436 /* Close all channel fd/socket. */
437 static void
channel_close_fds(struct ssh * ssh,Channel * c)438 channel_close_fds(struct ssh *ssh, Channel *c)
439 {
440 int sock = c->sock, rfd = c->rfd, wfd = c->wfd, efd = c->efd;
441
442 channel_close_fd(ssh, &c->sock);
443 if (rfd != sock)
444 channel_close_fd(ssh, &c->rfd);
445 if (wfd != sock && wfd != rfd)
446 channel_close_fd(ssh, &c->wfd);
447 if (efd != sock && efd != rfd && efd != wfd)
448 channel_close_fd(ssh, &c->efd);
449 }
450
451 static void
fwd_perm_clear(struct permission * perm)452 fwd_perm_clear(struct permission *perm)
453 {
454 free(perm->host_to_connect);
455 free(perm->listen_host);
456 free(perm->listen_path);
457 memset(perm, 0, sizeof(*perm));
458 }
459
460 /* Returns an printable name for the specified forwarding permission list */
461 static const char *
fwd_ident(int who,int where)462 fwd_ident(int who, int where)
463 {
464 if (who == FORWARD_ADM) {
465 if (where == FORWARD_LOCAL)
466 return "admin local";
467 else if (where == FORWARD_REMOTE)
468 return "admin remote";
469 } else if (who == FORWARD_USER) {
470 if (where == FORWARD_LOCAL)
471 return "user local";
472 else if (where == FORWARD_REMOTE)
473 return "user remote";
474 }
475 fatal("Unknown forward permission list %d/%d", who, where);
476 }
477
478 /* Returns the forwarding permission list for the specified direction */
479 static struct permission_set *
permission_set_get(struct ssh * ssh,int where)480 permission_set_get(struct ssh *ssh, int where)
481 {
482 struct ssh_channels *sc = ssh->chanctxt;
483
484 switch (where) {
485 case FORWARD_LOCAL:
486 return &sc->local_perms;
487 break;
488 case FORWARD_REMOTE:
489 return &sc->remote_perms;
490 break;
491 default:
492 fatal("%s: invalid forwarding direction %d", __func__, where);
493 }
494 }
495
496 /* Returns pointers to the specified forwarding list and its element count */
497 static void
permission_set_get_array(struct ssh * ssh,int who,int where,struct permission *** permpp,u_int ** npermpp)498 permission_set_get_array(struct ssh *ssh, int who, int where,
499 struct permission ***permpp, u_int **npermpp)
500 {
501 struct permission_set *pset = permission_set_get(ssh, where);
502
503 switch (who) {
504 case FORWARD_USER:
505 *permpp = &pset->permitted_user;
506 *npermpp = &pset->num_permitted_user;
507 break;
508 case FORWARD_ADM:
509 *permpp = &pset->permitted_admin;
510 *npermpp = &pset->num_permitted_admin;
511 break;
512 default:
513 fatal("%s: invalid forwarding client %d", __func__, who);
514 }
515 }
516
517 /* Adds an entry to the spcified forwarding list */
518 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)519 permission_set_add(struct ssh *ssh, int who, int where,
520 const char *host_to_connect, int port_to_connect,
521 const char *listen_host, const char *listen_path, int listen_port,
522 Channel *downstream)
523 {
524 struct permission **permp;
525 u_int n, *npermp;
526
527 permission_set_get_array(ssh, who, where, &permp, &npermp);
528
529 if (*npermp >= INT_MAX)
530 fatal("%s: %s overflow", __func__, fwd_ident(who, where));
531
532 *permp = xrecallocarray(*permp, *npermp, *npermp + 1, sizeof(**permp));
533 n = (*npermp)++;
534 #define MAYBE_DUP(s) ((s == NULL) ? NULL : xstrdup(s))
535 (*permp)[n].host_to_connect = MAYBE_DUP(host_to_connect);
536 (*permp)[n].port_to_connect = port_to_connect;
537 (*permp)[n].listen_host = MAYBE_DUP(listen_host);
538 (*permp)[n].listen_path = MAYBE_DUP(listen_path);
539 (*permp)[n].listen_port = listen_port;
540 (*permp)[n].downstream = downstream;
541 #undef MAYBE_DUP
542 return (int)n;
543 }
544
545 static void
mux_remove_remote_forwardings(struct ssh * ssh,Channel * c)546 mux_remove_remote_forwardings(struct ssh *ssh, Channel *c)
547 {
548 struct ssh_channels *sc = ssh->chanctxt;
549 struct permission_set *pset = &sc->local_perms;
550 struct permission *perm;
551 int r;
552 u_int i;
553
554 for (i = 0; i < pset->num_permitted_user; i++) {
555 perm = &pset->permitted_user[i];
556 if (perm->downstream != c)
557 continue;
558
559 /* cancel on the server, since mux client is gone */
560 debug("channel %d: cleanup remote forward for %s:%u",
561 c->self, perm->listen_host, perm->listen_port);
562 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 ||
563 (r = sshpkt_put_cstring(ssh,
564 "cancel-tcpip-forward")) != 0 ||
565 (r = sshpkt_put_u8(ssh, 0)) != 0 ||
566 (r = sshpkt_put_cstring(ssh,
567 channel_rfwd_bind_host(perm->listen_host))) != 0 ||
568 (r = sshpkt_put_u32(ssh, perm->listen_port)) != 0 ||
569 (r = sshpkt_send(ssh)) != 0) {
570 fatal("%s: channel %i: %s", __func__,
571 c->self, ssh_err(r));
572 }
573 fwd_perm_clear(perm); /* unregister */
574 }
575 }
576
577 /* Free the channel and close its fd/socket. */
578 void
channel_free(struct ssh * ssh,Channel * c)579 channel_free(struct ssh *ssh, Channel *c)
580 {
581 struct ssh_channels *sc = ssh->chanctxt;
582 char *s;
583 u_int i, n;
584 Channel *other;
585 struct channel_confirm *cc;
586
587 for (n = 0, i = 0; i < sc->channels_alloc; i++) {
588 if ((other = sc->channels[i]) == NULL)
589 continue;
590 n++;
591 /* detach from mux client and prepare for closing */
592 if (c->type == SSH_CHANNEL_MUX_CLIENT &&
593 other->type == SSH_CHANNEL_MUX_PROXY &&
594 other->mux_ctx == c) {
595 other->mux_ctx = NULL;
596 other->type = SSH_CHANNEL_OPEN;
597 other->istate = CHAN_INPUT_CLOSED;
598 other->ostate = CHAN_OUTPUT_CLOSED;
599 }
600 }
601 debug("channel %d: free: %s, nchannels %u", c->self,
602 c->remote_name ? c->remote_name : "???", n);
603
604 if (c->type == SSH_CHANNEL_MUX_CLIENT)
605 mux_remove_remote_forwardings(ssh, c);
606
607 if (log_level_get() >= SYSLOG_LEVEL_DEBUG3) {
608 s = channel_open_message(ssh);
609 debug3("channel %d: status: %s", c->self, s);
610 free(s);
611 }
612
613 channel_close_fds(ssh, c);
614 sshbuf_free(c->input);
615 sshbuf_free(c->output);
616 sshbuf_free(c->extended);
617 c->input = c->output = c->extended = NULL;
618 free(c->remote_name);
619 c->remote_name = NULL;
620 free(c->path);
621 c->path = NULL;
622 free(c->listening_addr);
623 c->listening_addr = NULL;
624 while ((cc = TAILQ_FIRST(&c->status_confirms)) != NULL) {
625 if (cc->abandon_cb != NULL)
626 cc->abandon_cb(ssh, c, cc->ctx);
627 TAILQ_REMOVE(&c->status_confirms, cc, entry);
628 freezero(cc, sizeof(*cc));
629 }
630 if (c->filter_cleanup != NULL && c->filter_ctx != NULL)
631 c->filter_cleanup(ssh, c->self, c->filter_ctx);
632 sc->channels[c->self] = NULL;
633 freezero(c, sizeof(*c));
634 }
635
636 void
channel_free_all(struct ssh * ssh)637 channel_free_all(struct ssh *ssh)
638 {
639 u_int i;
640 struct ssh_channels *sc = ssh->chanctxt;
641
642 for (i = 0; i < sc->channels_alloc; i++)
643 if (sc->channels[i] != NULL)
644 channel_free(ssh, sc->channels[i]);
645
646 free(sc->channels);
647 sc->channels = NULL;
648 sc->channels_alloc = 0;
649 sc->channel_max_fd = 0;
650
651 free(sc->x11_saved_display);
652 sc->x11_saved_display = NULL;
653
654 free(sc->x11_saved_proto);
655 sc->x11_saved_proto = NULL;
656
657 free(sc->x11_saved_data);
658 sc->x11_saved_data = NULL;
659 sc->x11_saved_data_len = 0;
660
661 free(sc->x11_fake_data);
662 sc->x11_fake_data = NULL;
663 sc->x11_fake_data_len = 0;
664 }
665
666 /*
667 * Closes the sockets/fds of all channels. This is used to close extra file
668 * descriptors after a fork.
669 */
670 void
channel_close_all(struct ssh * ssh)671 channel_close_all(struct ssh *ssh)
672 {
673 u_int i;
674
675 for (i = 0; i < ssh->chanctxt->channels_alloc; i++)
676 if (ssh->chanctxt->channels[i] != NULL)
677 channel_close_fds(ssh, ssh->chanctxt->channels[i]);
678 }
679
680 /*
681 * Stop listening to channels.
682 */
683 void
channel_stop_listening(struct ssh * ssh)684 channel_stop_listening(struct ssh *ssh)
685 {
686 u_int i;
687 Channel *c;
688
689 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) {
690 c = ssh->chanctxt->channels[i];
691 if (c != NULL) {
692 switch (c->type) {
693 case SSH_CHANNEL_AUTH_SOCKET:
694 case SSH_CHANNEL_PORT_LISTENER:
695 case SSH_CHANNEL_RPORT_LISTENER:
696 case SSH_CHANNEL_X11_LISTENER:
697 case SSH_CHANNEL_UNIX_LISTENER:
698 case SSH_CHANNEL_RUNIX_LISTENER:
699 channel_close_fd(ssh, &c->sock);
700 channel_free(ssh, c);
701 break;
702 }
703 }
704 }
705 }
706
707 /*
708 * Returns true if no channel has too much buffered data, and false if one or
709 * more channel is overfull.
710 */
711 int
channel_not_very_much_buffered_data(struct ssh * ssh)712 channel_not_very_much_buffered_data(struct ssh *ssh)
713 {
714 u_int i;
715 u_int maxsize = ssh_packet_get_maxsize(ssh);
716 Channel *c;
717
718 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) {
719 c = ssh->chanctxt->channels[i];
720 if (c == NULL || c->type != SSH_CHANNEL_OPEN)
721 continue;
722 if (sshbuf_len(c->output) > maxsize) {
723 debug2("channel %d: big output buffer %zu > %u",
724 c->self, sshbuf_len(c->output), maxsize);
725 return 0;
726 }
727 }
728 return 1;
729 }
730
731 /* Returns true if any channel is still open. */
732 int
channel_still_open(struct ssh * ssh)733 channel_still_open(struct ssh *ssh)
734 {
735 u_int i;
736 Channel *c;
737
738 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) {
739 c = ssh->chanctxt->channels[i];
740 if (c == NULL)
741 continue;
742 switch (c->type) {
743 case SSH_CHANNEL_X11_LISTENER:
744 case SSH_CHANNEL_PORT_LISTENER:
745 case SSH_CHANNEL_RPORT_LISTENER:
746 case SSH_CHANNEL_MUX_LISTENER:
747 case SSH_CHANNEL_CLOSED:
748 case SSH_CHANNEL_AUTH_SOCKET:
749 case SSH_CHANNEL_DYNAMIC:
750 case SSH_CHANNEL_RDYNAMIC_OPEN:
751 case SSH_CHANNEL_CONNECTING:
752 case SSH_CHANNEL_ZOMBIE:
753 case SSH_CHANNEL_ABANDONED:
754 case SSH_CHANNEL_UNIX_LISTENER:
755 case SSH_CHANNEL_RUNIX_LISTENER:
756 continue;
757 case SSH_CHANNEL_LARVAL:
758 continue;
759 case SSH_CHANNEL_OPENING:
760 case SSH_CHANNEL_OPEN:
761 case SSH_CHANNEL_RDYNAMIC_FINISH:
762 case SSH_CHANNEL_X11_OPEN:
763 case SSH_CHANNEL_MUX_CLIENT:
764 case SSH_CHANNEL_MUX_PROXY:
765 return 1;
766 default:
767 fatal("%s: bad channel type %d", __func__, c->type);
768 /* NOTREACHED */
769 }
770 }
771 return 0;
772 }
773
774 /* Returns the id of an open channel suitable for keepaliving */
775 int
channel_find_open(struct ssh * ssh)776 channel_find_open(struct ssh *ssh)
777 {
778 u_int i;
779 Channel *c;
780
781 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) {
782 c = ssh->chanctxt->channels[i];
783 if (c == NULL || !c->have_remote_id)
784 continue;
785 switch (c->type) {
786 case SSH_CHANNEL_CLOSED:
787 case SSH_CHANNEL_DYNAMIC:
788 case SSH_CHANNEL_RDYNAMIC_OPEN:
789 case SSH_CHANNEL_RDYNAMIC_FINISH:
790 case SSH_CHANNEL_X11_LISTENER:
791 case SSH_CHANNEL_PORT_LISTENER:
792 case SSH_CHANNEL_RPORT_LISTENER:
793 case SSH_CHANNEL_MUX_LISTENER:
794 case SSH_CHANNEL_MUX_CLIENT:
795 case SSH_CHANNEL_MUX_PROXY:
796 case SSH_CHANNEL_OPENING:
797 case SSH_CHANNEL_CONNECTING:
798 case SSH_CHANNEL_ZOMBIE:
799 case SSH_CHANNEL_ABANDONED:
800 case SSH_CHANNEL_UNIX_LISTENER:
801 case SSH_CHANNEL_RUNIX_LISTENER:
802 continue;
803 case SSH_CHANNEL_LARVAL:
804 case SSH_CHANNEL_AUTH_SOCKET:
805 case SSH_CHANNEL_OPEN:
806 case SSH_CHANNEL_X11_OPEN:
807 return i;
808 default:
809 fatal("%s: bad channel type %d", __func__, c->type);
810 /* NOTREACHED */
811 }
812 }
813 return -1;
814 }
815
816 /* Returns the state of the channel's extended usage flag */
817 const char *
channel_format_extended_usage(const Channel * c)818 channel_format_extended_usage(const Channel *c)
819 {
820 if (c->efd == -1)
821 return "closed";
822
823 switch (c->extended_usage) {
824 case CHAN_EXTENDED_WRITE:
825 return "write";
826 case CHAN_EXTENDED_READ:
827 return "read";
828 case CHAN_EXTENDED_IGNORE:
829 return "ignore";
830 default:
831 return "UNKNOWN";
832 }
833 }
834
835 static char *
channel_format_status(const Channel * c)836 channel_format_status(const Channel *c)
837 {
838 char *ret = NULL;
839
840 xasprintf(&ret, "t%d %s%u i%u/%zu o%u/%zu e[%s]/%zu "
841 "fd %d/%d/%d sock %d cc %d",
842 c->type,
843 c->have_remote_id ? "r" : "nr", c->remote_id,
844 c->istate, sshbuf_len(c->input),
845 c->ostate, sshbuf_len(c->output),
846 channel_format_extended_usage(c), sshbuf_len(c->extended),
847 c->rfd, c->wfd, c->efd, c->sock, c->ctl_chan);
848 return ret;
849 }
850
851 /*
852 * Returns a message describing the currently open forwarded connections,
853 * suitable for sending to the client. The message contains crlf pairs for
854 * newlines.
855 */
856 char *
channel_open_message(struct ssh * ssh)857 channel_open_message(struct ssh *ssh)
858 {
859 struct sshbuf *buf;
860 Channel *c;
861 u_int i;
862 int r;
863 char *cp, *ret;
864
865 if ((buf = sshbuf_new()) == NULL)
866 fatal("%s: sshbuf_new", __func__);
867 if ((r = sshbuf_putf(buf,
868 "The following connections are open:\r\n")) != 0)
869 fatal("%s: sshbuf_putf: %s", __func__, ssh_err(r));
870 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) {
871 c = ssh->chanctxt->channels[i];
872 if (c == NULL)
873 continue;
874 switch (c->type) {
875 case SSH_CHANNEL_X11_LISTENER:
876 case SSH_CHANNEL_PORT_LISTENER:
877 case SSH_CHANNEL_RPORT_LISTENER:
878 case SSH_CHANNEL_CLOSED:
879 case SSH_CHANNEL_AUTH_SOCKET:
880 case SSH_CHANNEL_ZOMBIE:
881 case SSH_CHANNEL_ABANDONED:
882 case SSH_CHANNEL_MUX_LISTENER:
883 case SSH_CHANNEL_UNIX_LISTENER:
884 case SSH_CHANNEL_RUNIX_LISTENER:
885 continue;
886 case SSH_CHANNEL_LARVAL:
887 case SSH_CHANNEL_OPENING:
888 case SSH_CHANNEL_CONNECTING:
889 case SSH_CHANNEL_DYNAMIC:
890 case SSH_CHANNEL_RDYNAMIC_OPEN:
891 case SSH_CHANNEL_RDYNAMIC_FINISH:
892 case SSH_CHANNEL_OPEN:
893 case SSH_CHANNEL_X11_OPEN:
894 case SSH_CHANNEL_MUX_PROXY:
895 case SSH_CHANNEL_MUX_CLIENT:
896 cp = channel_format_status(c);
897 if ((r = sshbuf_putf(buf, " #%d %.300s (%s)\r\n",
898 c->self, c->remote_name, cp)) != 0) {
899 free(cp);
900 fatal("%s: sshbuf_putf: %s",
901 __func__, ssh_err(r));
902 }
903 free(cp);
904 continue;
905 default:
906 fatal("%s: bad channel type %d", __func__, c->type);
907 /* NOTREACHED */
908 }
909 }
910 if ((ret = sshbuf_dup_string(buf)) == NULL)
911 fatal("%s: sshbuf_dup_string", __func__);
912 sshbuf_free(buf);
913 return ret;
914 }
915
916 static void
open_preamble(struct ssh * ssh,const char * where,Channel * c,const char * type)917 open_preamble(struct ssh *ssh, const char *where, Channel *c, const char *type)
918 {
919 int r;
920
921 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN)) != 0 ||
922 (r = sshpkt_put_cstring(ssh, type)) != 0 ||
923 (r = sshpkt_put_u32(ssh, c->self)) != 0 ||
924 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 ||
925 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0) {
926 fatal("%s: channel %i: open: %s", where, c->self, ssh_err(r));
927 }
928 }
929
930 void
channel_send_open(struct ssh * ssh,int id)931 channel_send_open(struct ssh *ssh, int id)
932 {
933 Channel *c = channel_lookup(ssh, id);
934 int r;
935
936 if (c == NULL) {
937 logit("channel_send_open: %d: bad id", id);
938 return;
939 }
940 debug2("channel %d: send open", id);
941 open_preamble(ssh, __func__, c, c->ctype);
942 if ((r = sshpkt_send(ssh)) != 0)
943 fatal("%s: channel %i: %s", __func__, c->self, ssh_err(r));
944 }
945
946 void
channel_request_start(struct ssh * ssh,int id,char * service,int wantconfirm)947 channel_request_start(struct ssh *ssh, int id, char *service, int wantconfirm)
948 {
949 Channel *c = channel_lookup(ssh, id);
950 int r;
951
952 if (c == NULL) {
953 logit("%s: %d: unknown channel id", __func__, id);
954 return;
955 }
956 if (!c->have_remote_id)
957 fatal(":%s: channel %d: no remote id", __func__, c->self);
958
959 debug2("channel %d: request %s confirm %d", id, service, wantconfirm);
960 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_REQUEST)) != 0 ||
961 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 ||
962 (r = sshpkt_put_cstring(ssh, service)) != 0 ||
963 (r = sshpkt_put_u8(ssh, wantconfirm)) != 0) {
964 fatal("%s: channel %i: %s", __func__, c->self, ssh_err(r));
965 }
966 }
967
968 void
channel_register_status_confirm(struct ssh * ssh,int id,channel_confirm_cb * cb,channel_confirm_abandon_cb * abandon_cb,void * ctx)969 channel_register_status_confirm(struct ssh *ssh, int id,
970 channel_confirm_cb *cb, channel_confirm_abandon_cb *abandon_cb, void *ctx)
971 {
972 struct channel_confirm *cc;
973 Channel *c;
974
975 if ((c = channel_lookup(ssh, id)) == NULL)
976 fatal("%s: %d: bad id", __func__, id);
977
978 cc = xcalloc(1, sizeof(*cc));
979 cc->cb = cb;
980 cc->abandon_cb = abandon_cb;
981 cc->ctx = ctx;
982 TAILQ_INSERT_TAIL(&c->status_confirms, cc, entry);
983 }
984
985 void
channel_register_open_confirm(struct ssh * ssh,int id,channel_open_fn * fn,void * ctx)986 channel_register_open_confirm(struct ssh *ssh, int id,
987 channel_open_fn *fn, void *ctx)
988 {
989 Channel *c = channel_lookup(ssh, id);
990
991 if (c == NULL) {
992 logit("%s: %d: bad id", __func__, id);
993 return;
994 }
995 c->open_confirm = fn;
996 c->open_confirm_ctx = ctx;
997 }
998
999 void
channel_register_cleanup(struct ssh * ssh,int id,channel_callback_fn * fn,int do_close)1000 channel_register_cleanup(struct ssh *ssh, int id,
1001 channel_callback_fn *fn, int do_close)
1002 {
1003 Channel *c = channel_by_id(ssh, id);
1004
1005 if (c == NULL) {
1006 logit("%s: %d: bad id", __func__, id);
1007 return;
1008 }
1009 c->detach_user = fn;
1010 c->detach_close = do_close;
1011 }
1012
1013 void
channel_cancel_cleanup(struct ssh * ssh,int id)1014 channel_cancel_cleanup(struct ssh *ssh, int id)
1015 {
1016 Channel *c = channel_by_id(ssh, id);
1017
1018 if (c == NULL) {
1019 logit("%s: %d: bad id", __func__, id);
1020 return;
1021 }
1022 c->detach_user = NULL;
1023 c->detach_close = 0;
1024 }
1025
1026 void
channel_register_filter(struct ssh * ssh,int id,channel_infilter_fn * ifn,channel_outfilter_fn * ofn,channel_filter_cleanup_fn * cfn,void * ctx)1027 channel_register_filter(struct ssh *ssh, int id, channel_infilter_fn *ifn,
1028 channel_outfilter_fn *ofn, channel_filter_cleanup_fn *cfn, void *ctx)
1029 {
1030 Channel *c = channel_lookup(ssh, id);
1031
1032 if (c == NULL) {
1033 logit("%s: %d: bad id", __func__, id);
1034 return;
1035 }
1036 c->input_filter = ifn;
1037 c->output_filter = ofn;
1038 c->filter_ctx = ctx;
1039 c->filter_cleanup = cfn;
1040 }
1041
1042 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)1043 channel_set_fds(struct ssh *ssh, int id, int rfd, int wfd, int efd,
1044 int extusage, int nonblock, int is_tty, u_int window_max)
1045 {
1046 Channel *c = channel_lookup(ssh, id);
1047 int r;
1048
1049 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
1050 fatal("channel_activate for non-larval channel %d.", id);
1051 if (!c->have_remote_id)
1052 fatal(":%s: channel %d: no remote id", __func__, c->self);
1053
1054 channel_register_fds(ssh, c, rfd, wfd, efd, extusage, nonblock, is_tty);
1055 c->type = SSH_CHANNEL_OPEN;
1056 c->local_window = c->local_window_max = window_max;
1057
1058 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST)) != 0 ||
1059 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 ||
1060 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 ||
1061 (r = sshpkt_send(ssh)) != 0)
1062 fatal("%s: channel %i: %s", __func__, c->self, ssh_err(r));
1063 }
1064
1065 static void
channel_pre_listener(struct ssh * ssh,Channel * c,fd_set * readset,fd_set * writeset)1066 channel_pre_listener(struct ssh *ssh, Channel *c,
1067 fd_set *readset, fd_set *writeset)
1068 {
1069 FD_SET(c->sock, readset);
1070 }
1071
1072 static void
channel_pre_connecting(struct ssh * ssh,Channel * c,fd_set * readset,fd_set * writeset)1073 channel_pre_connecting(struct ssh *ssh, Channel *c,
1074 fd_set *readset, fd_set *writeset)
1075 {
1076 debug3("channel %d: waiting for connection", c->self);
1077 FD_SET(c->sock, writeset);
1078 }
1079
1080 static void
channel_pre_open(struct ssh * ssh,Channel * c,fd_set * readset,fd_set * writeset)1081 channel_pre_open(struct ssh *ssh, Channel *c,
1082 fd_set *readset, fd_set *writeset)
1083 {
1084 if (c->istate == CHAN_INPUT_OPEN &&
1085 c->remote_window > 0 &&
1086 sshbuf_len(c->input) < c->remote_window &&
1087 sshbuf_check_reserve(c->input, CHAN_RBUF) == 0)
1088 FD_SET(c->rfd, readset);
1089 if (c->ostate == CHAN_OUTPUT_OPEN ||
1090 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
1091 if (sshbuf_len(c->output) > 0) {
1092 FD_SET(c->wfd, writeset);
1093 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
1094 if (CHANNEL_EFD_OUTPUT_ACTIVE(c))
1095 debug2("channel %d: "
1096 "obuf_empty delayed efd %d/(%zu)", c->self,
1097 c->efd, sshbuf_len(c->extended));
1098 else
1099 chan_obuf_empty(ssh, c);
1100 }
1101 }
1102 /** XXX check close conditions, too */
1103 if (c->efd != -1 && !(c->istate == CHAN_INPUT_CLOSED &&
1104 c->ostate == CHAN_OUTPUT_CLOSED)) {
1105 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1106 sshbuf_len(c->extended) > 0)
1107 FD_SET(c->efd, writeset);
1108 else if (c->efd != -1 && !(c->flags & CHAN_EOF_SENT) &&
1109 (c->extended_usage == CHAN_EXTENDED_READ ||
1110 c->extended_usage == CHAN_EXTENDED_IGNORE) &&
1111 sshbuf_len(c->extended) < c->remote_window)
1112 FD_SET(c->efd, readset);
1113 }
1114 /* XXX: What about efd? races? */
1115 }
1116
1117 /*
1118 * This is a special state for X11 authentication spoofing. An opened X11
1119 * connection (when authentication spoofing is being done) remains in this
1120 * state until the first packet has been completely read. The authentication
1121 * data in that packet is then substituted by the real data if it matches the
1122 * fake data, and the channel is put into normal mode.
1123 * XXX All this happens at the client side.
1124 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
1125 */
1126 static int
x11_open_helper(struct ssh * ssh,struct sshbuf * b)1127 x11_open_helper(struct ssh *ssh, struct sshbuf *b)
1128 {
1129 struct ssh_channels *sc = ssh->chanctxt;
1130 u_char *ucp;
1131 u_int proto_len, data_len;
1132
1133 /* Is this being called after the refusal deadline? */
1134 if (sc->x11_refuse_time != 0 &&
1135 (u_int)monotime() >= sc->x11_refuse_time) {
1136 verbose("Rejected X11 connection after ForwardX11Timeout "
1137 "expired");
1138 return -1;
1139 }
1140
1141 /* Check if the fixed size part of the packet is in buffer. */
1142 if (sshbuf_len(b) < 12)
1143 return 0;
1144
1145 /* Parse the lengths of variable-length fields. */
1146 ucp = sshbuf_mutable_ptr(b);
1147 if (ucp[0] == 0x42) { /* Byte order MSB first. */
1148 proto_len = 256 * ucp[6] + ucp[7];
1149 data_len = 256 * ucp[8] + ucp[9];
1150 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
1151 proto_len = ucp[6] + 256 * ucp[7];
1152 data_len = ucp[8] + 256 * ucp[9];
1153 } else {
1154 debug2("Initial X11 packet contains bad byte order byte: 0x%x",
1155 ucp[0]);
1156 return -1;
1157 }
1158
1159 /* Check if the whole packet is in buffer. */
1160 if (sshbuf_len(b) <
1161 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
1162 return 0;
1163
1164 /* Check if authentication protocol matches. */
1165 if (proto_len != strlen(sc->x11_saved_proto) ||
1166 memcmp(ucp + 12, sc->x11_saved_proto, proto_len) != 0) {
1167 debug2("X11 connection uses different authentication protocol.");
1168 return -1;
1169 }
1170 /* Check if authentication data matches our fake data. */
1171 if (data_len != sc->x11_fake_data_len ||
1172 timingsafe_bcmp(ucp + 12 + ((proto_len + 3) & ~3),
1173 sc->x11_fake_data, sc->x11_fake_data_len) != 0) {
1174 debug2("X11 auth data does not match fake data.");
1175 return -1;
1176 }
1177 /* Check fake data length */
1178 if (sc->x11_fake_data_len != sc->x11_saved_data_len) {
1179 error("X11 fake_data_len %d != saved_data_len %d",
1180 sc->x11_fake_data_len, sc->x11_saved_data_len);
1181 return -1;
1182 }
1183 /*
1184 * Received authentication protocol and data match
1185 * our fake data. Substitute the fake data with real
1186 * data.
1187 */
1188 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
1189 sc->x11_saved_data, sc->x11_saved_data_len);
1190 return 1;
1191 }
1192
1193 static void
channel_pre_x11_open(struct ssh * ssh,Channel * c,fd_set * readset,fd_set * writeset)1194 channel_pre_x11_open(struct ssh *ssh, Channel *c,
1195 fd_set *readset, fd_set *writeset)
1196 {
1197 int ret = x11_open_helper(ssh, c->output);
1198
1199 /* c->force_drain = 1; */
1200
1201 if (ret == 1) {
1202 c->type = SSH_CHANNEL_OPEN;
1203 channel_pre_open(ssh, c, readset, writeset);
1204 } else if (ret == -1) {
1205 logit("X11 connection rejected because of wrong authentication.");
1206 debug2("X11 rejected %d i%d/o%d",
1207 c->self, c->istate, c->ostate);
1208 chan_read_failed(ssh, c);
1209 sshbuf_reset(c->input);
1210 chan_ibuf_empty(ssh, c);
1211 sshbuf_reset(c->output);
1212 chan_write_failed(ssh, c);
1213 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
1214 }
1215 }
1216
1217 static void
channel_pre_mux_client(struct ssh * ssh,Channel * c,fd_set * readset,fd_set * writeset)1218 channel_pre_mux_client(struct ssh *ssh,
1219 Channel *c, fd_set *readset, fd_set *writeset)
1220 {
1221 if (c->istate == CHAN_INPUT_OPEN && !c->mux_pause &&
1222 sshbuf_check_reserve(c->input, CHAN_RBUF) == 0)
1223 FD_SET(c->rfd, readset);
1224 if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1225 /* clear buffer immediately (discard any partial packet) */
1226 sshbuf_reset(c->input);
1227 chan_ibuf_empty(ssh, c);
1228 /* Start output drain. XXX just kill chan? */
1229 chan_rcvd_oclose(ssh, c);
1230 }
1231 if (c->ostate == CHAN_OUTPUT_OPEN ||
1232 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
1233 if (sshbuf_len(c->output) > 0)
1234 FD_SET(c->wfd, writeset);
1235 else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN)
1236 chan_obuf_empty(ssh, c);
1237 }
1238 }
1239
1240 /* try to decode a socks4 header */
1241 static int
channel_decode_socks4(Channel * c,struct sshbuf * input,struct sshbuf * output)1242 channel_decode_socks4(Channel *c, struct sshbuf *input, struct sshbuf *output)
1243 {
1244 const u_char *p;
1245 char *host;
1246 u_int len, have, i, found, need;
1247 char username[256];
1248 struct {
1249 u_int8_t version;
1250 u_int8_t command;
1251 u_int16_t dest_port;
1252 struct in_addr dest_addr;
1253 } s4_req, s4_rsp;
1254 int r;
1255
1256 debug2("channel %d: decode socks4", c->self);
1257
1258 have = sshbuf_len(input);
1259 len = sizeof(s4_req);
1260 if (have < len)
1261 return 0;
1262 p = sshbuf_ptr(input);
1263
1264 need = 1;
1265 /* SOCKS4A uses an invalid IP address 0.0.0.x */
1266 if (p[4] == 0 && p[5] == 0 && p[6] == 0 && p[7] != 0) {
1267 debug2("channel %d: socks4a request", c->self);
1268 /* ... and needs an extra string (the hostname) */
1269 need = 2;
1270 }
1271 /* Check for terminating NUL on the string(s) */
1272 for (found = 0, i = len; i < have; i++) {
1273 if (p[i] == '\0') {
1274 found++;
1275 if (found == need)
1276 break;
1277 }
1278 if (i > 1024) {
1279 /* the peer is probably sending garbage */
1280 debug("channel %d: decode socks4: too long",
1281 c->self);
1282 return -1;
1283 }
1284 }
1285 if (found < need)
1286 return 0;
1287 if ((r = sshbuf_get(input, &s4_req.version, 1)) != 0 ||
1288 (r = sshbuf_get(input, &s4_req.command, 1)) != 0 ||
1289 (r = sshbuf_get(input, &s4_req.dest_port, 2)) != 0 ||
1290 (r = sshbuf_get(input, &s4_req.dest_addr, 4)) != 0) {
1291 debug("channels %d: decode socks4: %s", c->self, ssh_err(r));
1292 return -1;
1293 }
1294 have = sshbuf_len(input);
1295 p = sshbuf_ptr(input);
1296 if (memchr(p, '\0', have) == NULL) {
1297 error("channel %d: decode socks4: user not nul terminated",
1298 c->self);
1299 return -1;
1300 }
1301 len = strlen(p);
1302 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
1303 len++; /* trailing '\0' */
1304 strlcpy(username, p, sizeof(username));
1305 if ((r = sshbuf_consume(input, len)) != 0) {
1306 fatal("%s: channel %d: consume: %s", __func__,
1307 c->self, ssh_err(r));
1308 }
1309 free(c->path);
1310 c->path = NULL;
1311 if (need == 1) { /* SOCKS4: one string */
1312 host = inet_ntoa(s4_req.dest_addr);
1313 c->path = xstrdup(host);
1314 } else { /* SOCKS4A: two strings */
1315 have = sshbuf_len(input);
1316 p = sshbuf_ptr(input);
1317 if (memchr(p, '\0', have) == NULL) {
1318 error("channel %d: decode socks4a: host not nul "
1319 "terminated", c->self);
1320 return -1;
1321 }
1322 len = strlen(p);
1323 debug2("channel %d: decode socks4a: host %s/%d",
1324 c->self, p, len);
1325 len++; /* trailing '\0' */
1326 if (len > NI_MAXHOST) {
1327 error("channel %d: hostname \"%.100s\" too long",
1328 c->self, p);
1329 return -1;
1330 }
1331 c->path = xstrdup(p);
1332 if ((r = sshbuf_consume(input, len)) != 0) {
1333 fatal("%s: channel %d: consume: %s", __func__,
1334 c->self, ssh_err(r));
1335 }
1336 }
1337 c->host_port = ntohs(s4_req.dest_port);
1338
1339 debug2("channel %d: dynamic request: socks4 host %s port %u command %u",
1340 c->self, c->path, c->host_port, s4_req.command);
1341
1342 if (s4_req.command != 1) {
1343 debug("channel %d: cannot handle: %s cn %d",
1344 c->self, need == 1 ? "SOCKS4" : "SOCKS4A", s4_req.command);
1345 return -1;
1346 }
1347 s4_rsp.version = 0; /* vn: 0 for reply */
1348 s4_rsp.command = 90; /* cd: req granted */
1349 s4_rsp.dest_port = 0; /* ignored */
1350 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
1351 if ((r = sshbuf_put(output, &s4_rsp, sizeof(s4_rsp))) != 0) {
1352 fatal("%s: channel %d: append reply: %s", __func__,
1353 c->self, ssh_err(r));
1354 }
1355 return 1;
1356 }
1357
1358 /* try to decode a socks5 header */
1359 #define SSH_SOCKS5_AUTHDONE 0x1000
1360 #define SSH_SOCKS5_NOAUTH 0x00
1361 #define SSH_SOCKS5_IPV4 0x01
1362 #define SSH_SOCKS5_DOMAIN 0x03
1363 #define SSH_SOCKS5_IPV6 0x04
1364 #define SSH_SOCKS5_CONNECT 0x01
1365 #define SSH_SOCKS5_SUCCESS 0x00
1366
1367 static int
channel_decode_socks5(Channel * c,struct sshbuf * input,struct sshbuf * output)1368 channel_decode_socks5(Channel *c, struct sshbuf *input, struct sshbuf *output)
1369 {
1370 /* XXX use get/put_u8 instead of trusting struct padding */
1371 struct {
1372 u_int8_t version;
1373 u_int8_t command;
1374 u_int8_t reserved;
1375 u_int8_t atyp;
1376 } s5_req, s5_rsp;
1377 u_int16_t dest_port;
1378 char dest_addr[255+1], ntop[INET6_ADDRSTRLEN];
1379 const u_char *p;
1380 u_int have, need, i, found, nmethods, addrlen, af;
1381 int r;
1382
1383 debug2("channel %d: decode socks5", c->self);
1384 p = sshbuf_ptr(input);
1385 if (p[0] != 0x05)
1386 return -1;
1387 have = sshbuf_len(input);
1388 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) {
1389 /* format: ver | nmethods | methods */
1390 if (have < 2)
1391 return 0;
1392 nmethods = p[1];
1393 if (have < nmethods + 2)
1394 return 0;
1395 /* look for method: "NO AUTHENTICATION REQUIRED" */
1396 for (found = 0, i = 2; i < nmethods + 2; i++) {
1397 if (p[i] == SSH_SOCKS5_NOAUTH) {
1398 found = 1;
1399 break;
1400 }
1401 }
1402 if (!found) {
1403 debug("channel %d: method SSH_SOCKS5_NOAUTH not found",
1404 c->self);
1405 return -1;
1406 }
1407 if ((r = sshbuf_consume(input, nmethods + 2)) != 0) {
1408 fatal("%s: channel %d: consume: %s", __func__,
1409 c->self, ssh_err(r));
1410 }
1411 /* version, method */
1412 if ((r = sshbuf_put_u8(output, 0x05)) != 0 ||
1413 (r = sshbuf_put_u8(output, SSH_SOCKS5_NOAUTH)) != 0) {
1414 fatal("%s: channel %d: append reply: %s", __func__,
1415 c->self, ssh_err(r));
1416 }
1417 c->flags |= SSH_SOCKS5_AUTHDONE;
1418 debug2("channel %d: socks5 auth done", c->self);
1419 return 0; /* need more */
1420 }
1421 debug2("channel %d: socks5 post auth", c->self);
1422 if (have < sizeof(s5_req)+1)
1423 return 0; /* need more */
1424 memcpy(&s5_req, p, sizeof(s5_req));
1425 if (s5_req.version != 0x05 ||
1426 s5_req.command != SSH_SOCKS5_CONNECT ||
1427 s5_req.reserved != 0x00) {
1428 debug2("channel %d: only socks5 connect supported", c->self);
1429 return -1;
1430 }
1431 switch (s5_req.atyp){
1432 case SSH_SOCKS5_IPV4:
1433 addrlen = 4;
1434 af = AF_INET;
1435 break;
1436 case SSH_SOCKS5_DOMAIN:
1437 addrlen = p[sizeof(s5_req)];
1438 af = -1;
1439 break;
1440 case SSH_SOCKS5_IPV6:
1441 addrlen = 16;
1442 af = AF_INET6;
1443 break;
1444 default:
1445 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp);
1446 return -1;
1447 }
1448 need = sizeof(s5_req) + addrlen + 2;
1449 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1450 need++;
1451 if (have < need)
1452 return 0;
1453 if ((r = sshbuf_consume(input, sizeof(s5_req))) != 0) {
1454 fatal("%s: channel %d: consume: %s", __func__,
1455 c->self, ssh_err(r));
1456 }
1457 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) {
1458 /* host string length */
1459 if ((r = sshbuf_consume(input, 1)) != 0) {
1460 fatal("%s: channel %d: consume: %s", __func__,
1461 c->self, ssh_err(r));
1462 }
1463 }
1464 if ((r = sshbuf_get(input, &dest_addr, addrlen)) != 0 ||
1465 (r = sshbuf_get(input, &dest_port, 2)) != 0) {
1466 debug("channel %d: parse addr/port: %s", c->self, ssh_err(r));
1467 return -1;
1468 }
1469 dest_addr[addrlen] = '\0';
1470 free(c->path);
1471 c->path = NULL;
1472 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) {
1473 if (addrlen >= NI_MAXHOST) {
1474 error("channel %d: dynamic request: socks5 hostname "
1475 "\"%.100s\" too long", c->self, dest_addr);
1476 return -1;
1477 }
1478 c->path = xstrdup(dest_addr);
1479 } else {
1480 if (inet_ntop(af, dest_addr, ntop, sizeof(ntop)) == NULL)
1481 return -1;
1482 c->path = xstrdup(ntop);
1483 }
1484 c->host_port = ntohs(dest_port);
1485
1486 debug2("channel %d: dynamic request: socks5 host %s port %u command %u",
1487 c->self, c->path, c->host_port, s5_req.command);
1488
1489 s5_rsp.version = 0x05;
1490 s5_rsp.command = SSH_SOCKS5_SUCCESS;
1491 s5_rsp.reserved = 0; /* ignored */
1492 s5_rsp.atyp = SSH_SOCKS5_IPV4;
1493 dest_port = 0; /* ignored */
1494
1495 if ((r = sshbuf_put(output, &s5_rsp, sizeof(s5_rsp))) != 0 ||
1496 (r = sshbuf_put_u32(output, ntohl(INADDR_ANY))) != 0 ||
1497 (r = sshbuf_put(output, &dest_port, sizeof(dest_port))) != 0)
1498 fatal("%s: channel %d: append reply: %s", __func__,
1499 c->self, ssh_err(r));
1500 return 1;
1501 }
1502
1503 Channel *
channel_connect_stdio_fwd(struct ssh * ssh,const char * host_to_connect,u_short port_to_connect,int in,int out)1504 channel_connect_stdio_fwd(struct ssh *ssh,
1505 const char *host_to_connect, u_short port_to_connect, int in, int out)
1506 {
1507 Channel *c;
1508
1509 debug("%s %s:%d", __func__, host_to_connect, port_to_connect);
1510
1511 c = channel_new(ssh, "stdio-forward", SSH_CHANNEL_OPENING, in, out,
1512 -1, CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
1513 0, "stdio-forward", /*nonblock*/0);
1514
1515 c->path = xstrdup(host_to_connect);
1516 c->host_port = port_to_connect;
1517 c->listening_port = 0;
1518 c->force_drain = 1;
1519
1520 channel_register_fds(ssh, c, in, out, -1, 0, 1, 0);
1521 port_open_helper(ssh, c, "direct-tcpip");
1522
1523 return c;
1524 }
1525
1526 /* dynamic port forwarding */
1527 static void
channel_pre_dynamic(struct ssh * ssh,Channel * c,fd_set * readset,fd_set * writeset)1528 channel_pre_dynamic(struct ssh *ssh, Channel *c,
1529 fd_set *readset, fd_set *writeset)
1530 {
1531 const u_char *p;
1532 u_int have;
1533 int ret;
1534
1535 have = sshbuf_len(c->input);
1536 debug2("channel %d: pre_dynamic: have %d", c->self, have);
1537 /* sshbuf_dump(c->input, stderr); */
1538 /* check if the fixed size part of the packet is in buffer. */
1539 if (have < 3) {
1540 /* need more */
1541 FD_SET(c->sock, readset);
1542 return;
1543 }
1544 /* try to guess the protocol */
1545 p = sshbuf_ptr(c->input);
1546 /* XXX sshbuf_peek_u8? */
1547 switch (p[0]) {
1548 case 0x04:
1549 ret = channel_decode_socks4(c, c->input, c->output);
1550 break;
1551 case 0x05:
1552 ret = channel_decode_socks5(c, c->input, c->output);
1553 break;
1554 default:
1555 ret = -1;
1556 break;
1557 }
1558 if (ret < 0) {
1559 chan_mark_dead(ssh, c);
1560 } else if (ret == 0) {
1561 debug2("channel %d: pre_dynamic: need more", c->self);
1562 /* need more */
1563 FD_SET(c->sock, readset);
1564 if (sshbuf_len(c->output))
1565 FD_SET(c->sock, writeset);
1566 } else {
1567 /* switch to the next state */
1568 c->type = SSH_CHANNEL_OPENING;
1569 port_open_helper(ssh, c, "direct-tcpip");
1570 }
1571 }
1572
1573 /* simulate read-error */
1574 static void
rdynamic_close(struct ssh * ssh,Channel * c)1575 rdynamic_close(struct ssh *ssh, Channel *c)
1576 {
1577 c->type = SSH_CHANNEL_OPEN;
1578 chan_read_failed(ssh, c);
1579 sshbuf_reset(c->input);
1580 chan_ibuf_empty(ssh, c);
1581 sshbuf_reset(c->output);
1582 chan_write_failed(ssh, c);
1583 }
1584
1585 /* reverse dynamic port forwarding */
1586 static void
channel_before_prepare_select_rdynamic(struct ssh * ssh,Channel * c)1587 channel_before_prepare_select_rdynamic(struct ssh *ssh, Channel *c)
1588 {
1589 const u_char *p;
1590 u_int have, len;
1591 int r, ret;
1592
1593 have = sshbuf_len(c->output);
1594 debug2("channel %d: pre_rdynamic: have %d", c->self, have);
1595 /* sshbuf_dump(c->output, stderr); */
1596 /* EOF received */
1597 if (c->flags & CHAN_EOF_RCVD) {
1598 if ((r = sshbuf_consume(c->output, have)) != 0) {
1599 fatal("%s: channel %d: consume: %s",
1600 __func__, c->self, ssh_err(r));
1601 }
1602 rdynamic_close(ssh, c);
1603 return;
1604 }
1605 /* check if the fixed size part of the packet is in buffer. */
1606 if (have < 3)
1607 return;
1608 /* try to guess the protocol */
1609 p = sshbuf_ptr(c->output);
1610 switch (p[0]) {
1611 case 0x04:
1612 /* switch input/output for reverse forwarding */
1613 ret = channel_decode_socks4(c, c->output, c->input);
1614 break;
1615 case 0x05:
1616 ret = channel_decode_socks5(c, c->output, c->input);
1617 break;
1618 default:
1619 ret = -1;
1620 break;
1621 }
1622 if (ret < 0) {
1623 rdynamic_close(ssh, c);
1624 } else if (ret == 0) {
1625 debug2("channel %d: pre_rdynamic: need more", c->self);
1626 /* send socks request to peer */
1627 len = sshbuf_len(c->input);
1628 if (len > 0 && len < c->remote_window) {
1629 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 ||
1630 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 ||
1631 (r = sshpkt_put_stringb(ssh, c->input)) != 0 ||
1632 (r = sshpkt_send(ssh)) != 0) {
1633 fatal("%s: channel %i: rdynamic: %s", __func__,
1634 c->self, ssh_err(r));
1635 }
1636 if ((r = sshbuf_consume(c->input, len)) != 0) {
1637 fatal("%s: channel %d: consume: %s",
1638 __func__, c->self, ssh_err(r));
1639 }
1640 c->remote_window -= len;
1641 }
1642 } else if (rdynamic_connect_finish(ssh, c) < 0) {
1643 /* the connect failed */
1644 rdynamic_close(ssh, c);
1645 }
1646 }
1647
1648 /* This is our fake X11 server socket. */
1649 static void
channel_post_x11_listener(struct ssh * ssh,Channel * c,fd_set * readset,fd_set * writeset)1650 channel_post_x11_listener(struct ssh *ssh, Channel *c,
1651 fd_set *readset, fd_set *writeset)
1652 {
1653 Channel *nc;
1654 struct sockaddr_storage addr;
1655 int r, newsock, oerrno, remote_port;
1656 socklen_t addrlen;
1657 char buf[16384], *remote_ipaddr;
1658
1659 if (!FD_ISSET(c->sock, readset))
1660 return;
1661
1662 debug("X11 connection requested.");
1663 addrlen = sizeof(addr);
1664 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1665 if (c->single_connection) {
1666 oerrno = errno;
1667 debug2("single_connection: closing X11 listener.");
1668 channel_close_fd(ssh, &c->sock);
1669 chan_mark_dead(ssh, c);
1670 errno = oerrno;
1671 }
1672 if (newsock == -1) {
1673 if (errno != EINTR && errno != EWOULDBLOCK &&
1674 errno != ECONNABORTED)
1675 error("accept: %.100s", strerror(errno));
1676 if (errno == EMFILE || errno == ENFILE)
1677 c->notbefore = monotime() + 1;
1678 return;
1679 }
1680 set_nodelay(newsock);
1681 remote_ipaddr = get_peer_ipaddr(newsock);
1682 remote_port = get_peer_port(newsock);
1683 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1684 remote_ipaddr, remote_port);
1685
1686 nc = channel_new(ssh, "accepted x11 socket",
1687 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1688 c->local_window_max, c->local_maxpacket, 0, buf, 1);
1689 open_preamble(ssh, __func__, nc, "x11");
1690 if ((r = sshpkt_put_cstring(ssh, remote_ipaddr)) != 0 ||
1691 (r = sshpkt_put_u32(ssh, remote_port)) != 0) {
1692 fatal("%s: channel %i: reply %s", __func__,
1693 c->self, ssh_err(r));
1694 }
1695 if ((r = sshpkt_send(ssh)) != 0)
1696 fatal("%s: channel %i: send %s", __func__, c->self, ssh_err(r));
1697 free(remote_ipaddr);
1698 }
1699
1700 static void
port_open_helper(struct ssh * ssh,Channel * c,char * rtype)1701 port_open_helper(struct ssh *ssh, Channel *c, char *rtype)
1702 {
1703 char *local_ipaddr = get_local_ipaddr(c->sock);
1704 int local_port = c->sock == -1 ? 65536 : get_local_port(c->sock);
1705 char *remote_ipaddr = get_peer_ipaddr(c->sock);
1706 int remote_port = get_peer_port(c->sock);
1707 int r;
1708
1709 if (remote_port == -1) {
1710 /* Fake addr/port to appease peers that validate it (Tectia) */
1711 free(remote_ipaddr);
1712 remote_ipaddr = xstrdup("127.0.0.1");
1713 remote_port = 65535;
1714 }
1715
1716 free(c->remote_name);
1717 xasprintf(&c->remote_name,
1718 "%s: listening port %d for %.100s port %d, "
1719 "connect from %.200s port %d to %.100s port %d",
1720 rtype, c->listening_port, c->path, c->host_port,
1721 remote_ipaddr, remote_port, local_ipaddr, local_port);
1722
1723 open_preamble(ssh, __func__, c, rtype);
1724 if (strcmp(rtype, "direct-tcpip") == 0) {
1725 /* target host, port */
1726 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0 ||
1727 (r = sshpkt_put_u32(ssh, c->host_port)) != 0) {
1728 fatal("%s: channel %i: reply %s", __func__,
1729 c->self, ssh_err(r));
1730 }
1731 } else if (strcmp(rtype, "direct-streamlocal@openssh.com") == 0) {
1732 /* target path */
1733 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0) {
1734 fatal("%s: channel %i: reply %s", __func__,
1735 c->self, ssh_err(r));
1736 }
1737 } else if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) {
1738 /* listen path */
1739 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0) {
1740 fatal("%s: channel %i: reply %s", __func__,
1741 c->self, ssh_err(r));
1742 }
1743 } else {
1744 /* listen address, port */
1745 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0 ||
1746 (r = sshpkt_put_u32(ssh, local_port)) != 0) {
1747 fatal("%s: channel %i: reply %s", __func__,
1748 c->self, ssh_err(r));
1749 }
1750 }
1751 if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) {
1752 /* reserved for future owner/mode info */
1753 if ((r = sshpkt_put_cstring(ssh, "")) != 0) {
1754 fatal("%s: channel %i: reply %s", __func__,
1755 c->self, ssh_err(r));
1756 }
1757 } else {
1758 /* originator host and port */
1759 if ((r = sshpkt_put_cstring(ssh, remote_ipaddr)) != 0 ||
1760 (r = sshpkt_put_u32(ssh, (u_int)remote_port)) != 0) {
1761 fatal("%s: channel %i: reply %s", __func__,
1762 c->self, ssh_err(r));
1763 }
1764 }
1765 if ((r = sshpkt_send(ssh)) != 0)
1766 fatal("%s: channel %i: send %s", __func__, c->self, ssh_err(r));
1767 free(remote_ipaddr);
1768 free(local_ipaddr);
1769 }
1770
1771 void
channel_set_x11_refuse_time(struct ssh * ssh,u_int refuse_time)1772 channel_set_x11_refuse_time(struct ssh *ssh, u_int refuse_time)
1773 {
1774 ssh->chanctxt->x11_refuse_time = refuse_time;
1775 }
1776
1777 /*
1778 * This socket is listening for connections to a forwarded TCP/IP port.
1779 */
1780 static void
channel_post_port_listener(struct ssh * ssh,Channel * c,fd_set * readset,fd_set * writeset)1781 channel_post_port_listener(struct ssh *ssh, Channel *c,
1782 fd_set *readset, fd_set *writeset)
1783 {
1784 Channel *nc;
1785 struct sockaddr_storage addr;
1786 int newsock, nextstate;
1787 socklen_t addrlen;
1788 char *rtype;
1789
1790 if (!FD_ISSET(c->sock, readset))
1791 return;
1792
1793 debug("Connection to port %d forwarding to %.100s port %d requested.",
1794 c->listening_port, c->path, c->host_port);
1795
1796 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1797 nextstate = SSH_CHANNEL_OPENING;
1798 rtype = "forwarded-tcpip";
1799 } else if (c->type == SSH_CHANNEL_RUNIX_LISTENER) {
1800 nextstate = SSH_CHANNEL_OPENING;
1801 rtype = "forwarded-streamlocal@openssh.com";
1802 } else if (c->host_port == PORT_STREAMLOCAL) {
1803 nextstate = SSH_CHANNEL_OPENING;
1804 rtype = "direct-streamlocal@openssh.com";
1805 } else if (c->host_port == 0) {
1806 nextstate = SSH_CHANNEL_DYNAMIC;
1807 rtype = "dynamic-tcpip";
1808 } else {
1809 nextstate = SSH_CHANNEL_OPENING;
1810 rtype = "direct-tcpip";
1811 }
1812
1813 addrlen = sizeof(addr);
1814 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1815 if (newsock == -1) {
1816 if (errno != EINTR && errno != EWOULDBLOCK &&
1817 errno != ECONNABORTED)
1818 error("accept: %.100s", strerror(errno));
1819 if (errno == EMFILE || errno == ENFILE)
1820 c->notbefore = monotime() + 1;
1821 return;
1822 }
1823 if (c->host_port != PORT_STREAMLOCAL)
1824 set_nodelay(newsock);
1825 nc = channel_new(ssh, rtype, nextstate, newsock, newsock, -1,
1826 c->local_window_max, c->local_maxpacket, 0, rtype, 1);
1827 nc->listening_port = c->listening_port;
1828 nc->host_port = c->host_port;
1829 if (c->path != NULL)
1830 nc->path = xstrdup(c->path);
1831
1832 if (nextstate != SSH_CHANNEL_DYNAMIC)
1833 port_open_helper(ssh, nc, rtype);
1834 }
1835
1836 /*
1837 * This is the authentication agent socket listening for connections from
1838 * clients.
1839 */
1840 static void
channel_post_auth_listener(struct ssh * ssh,Channel * c,fd_set * readset,fd_set * writeset)1841 channel_post_auth_listener(struct ssh *ssh, Channel *c,
1842 fd_set *readset, fd_set *writeset)
1843 {
1844 Channel *nc;
1845 int r, newsock;
1846 struct sockaddr_storage addr;
1847 socklen_t addrlen;
1848
1849 if (!FD_ISSET(c->sock, readset))
1850 return;
1851
1852 addrlen = sizeof(addr);
1853 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1854 if (newsock == -1) {
1855 error("accept from auth socket: %.100s", strerror(errno));
1856 if (errno == EMFILE || errno == ENFILE)
1857 c->notbefore = monotime() + 1;
1858 return;
1859 }
1860 nc = channel_new(ssh, "accepted auth socket",
1861 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1862 c->local_window_max, c->local_maxpacket,
1863 0, "accepted auth socket", 1);
1864 open_preamble(ssh, __func__, nc, "auth-agent@openssh.com");
1865 if ((r = sshpkt_send(ssh)) != 0)
1866 fatal("%s: channel %i: %s", __func__, c->self, ssh_err(r));
1867 }
1868
1869 static void
channel_post_connecting(struct ssh * ssh,Channel * c,fd_set * readset,fd_set * writeset)1870 channel_post_connecting(struct ssh *ssh, Channel *c,
1871 fd_set *readset, fd_set *writeset)
1872 {
1873 int err = 0, sock, isopen, r;
1874 socklen_t sz = sizeof(err);
1875
1876 if (!FD_ISSET(c->sock, writeset))
1877 return;
1878 if (!c->have_remote_id)
1879 fatal(":%s: channel %d: no remote id", __func__, c->self);
1880 /* for rdynamic the OPEN_CONFIRMATION has been sent already */
1881 isopen = (c->type == SSH_CHANNEL_RDYNAMIC_FINISH);
1882 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) == -1) {
1883 err = errno;
1884 error("getsockopt SO_ERROR failed");
1885 }
1886 if (err == 0) {
1887 debug("channel %d: connected to %s port %d",
1888 c->self, c->connect_ctx.host, c->connect_ctx.port);
1889 channel_connect_ctx_free(&c->connect_ctx);
1890 c->type = SSH_CHANNEL_OPEN;
1891 if (isopen) {
1892 /* no message necessary */
1893 } else {
1894 if ((r = sshpkt_start(ssh,
1895 SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 ||
1896 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 ||
1897 (r = sshpkt_put_u32(ssh, c->self)) != 0 ||
1898 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 ||
1899 (r = sshpkt_put_u32(ssh, c->local_maxpacket))
1900 != 0)
1901 fatal("%s: channel %i: confirm: %s", __func__,
1902 c->self, ssh_err(r));
1903 if ((r = sshpkt_send(ssh)) != 0)
1904 fatal("%s: channel %i: %s", __func__, c->self,
1905 ssh_err(r));
1906 }
1907 } else {
1908 debug("channel %d: connection failed: %s",
1909 c->self, strerror(err));
1910 /* Try next address, if any */
1911 if ((sock = connect_next(&c->connect_ctx)) > 0) {
1912 close(c->sock);
1913 c->sock = c->rfd = c->wfd = sock;
1914 channel_find_maxfd(ssh->chanctxt);
1915 return;
1916 }
1917 /* Exhausted all addresses */
1918 error("connect_to %.100s port %d: failed.",
1919 c->connect_ctx.host, c->connect_ctx.port);
1920 channel_connect_ctx_free(&c->connect_ctx);
1921 if (isopen) {
1922 rdynamic_close(ssh, c);
1923 } else {
1924 if ((r = sshpkt_start(ssh,
1925 SSH2_MSG_CHANNEL_OPEN_FAILURE)) != 0 ||
1926 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 ||
1927 (r = sshpkt_put_u32(ssh,
1928 SSH2_OPEN_CONNECT_FAILED)) != 0 ||
1929 (r = sshpkt_put_cstring(ssh, strerror(err))) != 0 ||
1930 (r = sshpkt_put_cstring(ssh, "")) != 0) {
1931 fatal("%s: channel %i: failure: %s", __func__,
1932 c->self, ssh_err(r));
1933 }
1934 if ((r = sshpkt_send(ssh)) != 0)
1935 fatal("%s: channel %i: %s", __func__, c->self,
1936 ssh_err(r));
1937 chan_mark_dead(ssh, c);
1938 }
1939 }
1940 }
1941
1942 static int
channel_handle_rfd(struct ssh * ssh,Channel * c,fd_set * readset,fd_set * writeset)1943 channel_handle_rfd(struct ssh *ssh, Channel *c,
1944 fd_set *readset, fd_set *writeset)
1945 {
1946 char buf[CHAN_RBUF];
1947 ssize_t len;
1948 int r, force;
1949
1950 force = c->isatty && c->detach_close && c->istate != CHAN_INPUT_CLOSED;
1951
1952 if (c->rfd == -1 || (!force && !FD_ISSET(c->rfd, readset)))
1953 return 1;
1954
1955 errno = 0;
1956 len = read(c->rfd, buf, sizeof(buf));
1957 if (len == -1 && (errno == EINTR ||
1958 ((errno == EAGAIN || errno == EWOULDBLOCK) && !force)))
1959 return 1;
1960 #ifndef PTY_ZEROREAD
1961 if (len <= 0) {
1962 #else
1963 if ((!c->isatty && len <= 0) ||
1964 (c->isatty && (len < 0 || (len == 0 && errno != 0)))) {
1965 #endif
1966 debug2("channel %d: read<=0 rfd %d len %zd",
1967 c->self, c->rfd, len);
1968 if (c->type != SSH_CHANNEL_OPEN) {
1969 debug2("channel %d: not open", c->self);
1970 chan_mark_dead(ssh, c);
1971 return -1;
1972 } else {
1973 chan_read_failed(ssh, c);
1974 }
1975 return -1;
1976 }
1977 if (c->input_filter != NULL) {
1978 if (c->input_filter(ssh, c, buf, len) == -1) {
1979 debug2("channel %d: filter stops", c->self);
1980 chan_read_failed(ssh, c);
1981 }
1982 } else if (c->datagram) {
1983 if ((r = sshbuf_put_string(c->input, buf, len)) != 0)
1984 fatal("%s: channel %d: put datagram: %s", __func__,
1985 c->self, ssh_err(r));
1986 } else if ((r = sshbuf_put(c->input, buf, len)) != 0) {
1987 fatal("%s: channel %d: put data: %s", __func__,
1988 c->self, ssh_err(r));
1989 }
1990 return 1;
1991 }
1992
1993 static int
1994 channel_handle_wfd(struct ssh *ssh, Channel *c,
1995 fd_set *readset, fd_set *writeset)
1996 {
1997 struct termios tio;
1998 u_char *data = NULL, *buf; /* XXX const; need filter API change */
1999 size_t dlen, olen = 0;
2000 int r, len;
2001
2002 if (c->wfd == -1 || !FD_ISSET(c->wfd, writeset) ||
2003 sshbuf_len(c->output) == 0)
2004 return 1;
2005
2006 /* Send buffered output data to the socket. */
2007 olen = sshbuf_len(c->output);
2008 if (c->output_filter != NULL) {
2009 if ((buf = c->output_filter(ssh, c, &data, &dlen)) == NULL) {
2010 debug2("channel %d: filter stops", c->self);
2011 if (c->type != SSH_CHANNEL_OPEN)
2012 chan_mark_dead(ssh, c);
2013 else
2014 chan_write_failed(ssh, c);
2015 return -1;
2016 }
2017 } else if (c->datagram) {
2018 if ((r = sshbuf_get_string(c->output, &data, &dlen)) != 0)
2019 fatal("%s: channel %d: get datagram: %s", __func__,
2020 c->self, ssh_err(r));
2021 buf = data;
2022 } else {
2023 buf = data = sshbuf_mutable_ptr(c->output);
2024 dlen = sshbuf_len(c->output);
2025 }
2026
2027 if (c->datagram) {
2028 /* ignore truncated writes, datagrams might get lost */
2029 len = write(c->wfd, buf, dlen);
2030 free(data);
2031 if (len == -1 && (errno == EINTR || errno == EAGAIN ||
2032 errno == EWOULDBLOCK))
2033 return 1;
2034 if (len <= 0)
2035 goto write_fail;
2036 goto out;
2037 }
2038
2039 #ifdef _AIX
2040 /* XXX: Later AIX versions can't push as much data to tty */
2041 if (c->wfd_isatty)
2042 dlen = MIN(dlen, 8*1024);
2043 #endif
2044
2045 len = write(c->wfd, buf, dlen);
2046 if (len == -1 &&
2047 (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK))
2048 return 1;
2049 if (len <= 0) {
2050 write_fail:
2051 if (c->type != SSH_CHANNEL_OPEN) {
2052 debug2("channel %d: not open", c->self);
2053 chan_mark_dead(ssh, c);
2054 return -1;
2055 } else {
2056 chan_write_failed(ssh, c);
2057 }
2058 return -1;
2059 }
2060 #ifndef BROKEN_TCGETATTR_ICANON
2061 if (c->isatty && dlen >= 1 && buf[0] != '\r') {
2062 if (tcgetattr(c->wfd, &tio) == 0 &&
2063 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
2064 /*
2065 * Simulate echo to reduce the impact of
2066 * traffic analysis. We need to match the
2067 * size of a SSH2_MSG_CHANNEL_DATA message
2068 * (4 byte channel id + buf)
2069 */
2070 if ((r = sshpkt_msg_ignore(ssh, 4+len)) != 0 ||
2071 (r = sshpkt_send(ssh)) != 0)
2072 fatal("%s: channel %d: ignore: %s",
2073 __func__, c->self, ssh_err(r));
2074 }
2075 }
2076 #endif /* BROKEN_TCGETATTR_ICANON */
2077 if ((r = sshbuf_consume(c->output, len)) != 0) {
2078 fatal("%s: channel %d: consume: %s",
2079 __func__, c->self, ssh_err(r));
2080 }
2081 out:
2082 c->local_consumed += olen - sshbuf_len(c->output);
2083
2084 return 1;
2085 }
2086
2087 static int
2088 channel_handle_efd_write(struct ssh *ssh, Channel *c,
2089 fd_set *readset, fd_set *writeset)
2090 {
2091 int r;
2092 ssize_t len;
2093
2094 if (!FD_ISSET(c->efd, writeset) || sshbuf_len(c->extended) == 0)
2095 return 1;
2096
2097 len = write(c->efd, sshbuf_ptr(c->extended),
2098 sshbuf_len(c->extended));
2099 debug2("channel %d: written %zd to efd %d", c->self, len, c->efd);
2100 if (len == -1 && (errno == EINTR || errno == EAGAIN ||
2101 errno == EWOULDBLOCK))
2102 return 1;
2103 if (len <= 0) {
2104 debug2("channel %d: closing write-efd %d", c->self, c->efd);
2105 channel_close_fd(ssh, &c->efd);
2106 } else {
2107 if ((r = sshbuf_consume(c->extended, len)) != 0) {
2108 fatal("%s: channel %d: consume: %s",
2109 __func__, c->self, ssh_err(r));
2110 }
2111 c->local_consumed += len;
2112 }
2113 return 1;
2114 }
2115
2116 static int
2117 channel_handle_efd_read(struct ssh *ssh, Channel *c,
2118 fd_set *readset, fd_set *writeset)
2119 {
2120 char buf[CHAN_RBUF];
2121 ssize_t len;
2122 int r, force;
2123
2124 force = c->isatty && c->detach_close && c->istate != CHAN_INPUT_CLOSED;
2125
2126 if (c->efd == -1 || (!force && !FD_ISSET(c->efd, readset)))
2127 return 1;
2128
2129 len = read(c->efd, buf, sizeof(buf));
2130 debug2("channel %d: read %zd from efd %d", c->self, len, c->efd);
2131 if (len == -1 && (errno == EINTR || ((errno == EAGAIN ||
2132 errno == EWOULDBLOCK) && !force)))
2133 return 1;
2134 if (len <= 0) {
2135 debug2("channel %d: closing read-efd %d",
2136 c->self, c->efd);
2137 channel_close_fd(ssh, &c->efd);
2138 } else {
2139 if (c->extended_usage == CHAN_EXTENDED_IGNORE) {
2140 debug3("channel %d: discard efd",
2141 c->self);
2142 } else if ((r = sshbuf_put(c->extended, buf, len)) != 0) {
2143 fatal("%s: channel %d: append: %s",
2144 __func__, c->self, ssh_err(r));
2145 }
2146 }
2147 return 1;
2148 }
2149
2150 static int
2151 channel_handle_efd(struct ssh *ssh, Channel *c,
2152 fd_set *readset, fd_set *writeset)
2153 {
2154 if (c->efd == -1)
2155 return 1;
2156
2157 /** XXX handle drain efd, too */
2158
2159 if (c->extended_usage == CHAN_EXTENDED_WRITE)
2160 return channel_handle_efd_write(ssh, c, readset, writeset);
2161 else if (c->extended_usage == CHAN_EXTENDED_READ ||
2162 c->extended_usage == CHAN_EXTENDED_IGNORE)
2163 return channel_handle_efd_read(ssh, c, readset, writeset);
2164
2165 return 1;
2166 }
2167
2168 static int
2169 channel_check_window(struct ssh *ssh, Channel *c)
2170 {
2171 int r;
2172
2173 if (c->type == SSH_CHANNEL_OPEN &&
2174 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
2175 ((c->local_window_max - c->local_window >
2176 c->local_maxpacket*3) ||
2177 c->local_window < c->local_window_max/2) &&
2178 c->local_consumed > 0) {
2179 if (!c->have_remote_id)
2180 fatal(":%s: channel %d: no remote id",
2181 __func__, c->self);
2182 if ((r = sshpkt_start(ssh,
2183 SSH2_MSG_CHANNEL_WINDOW_ADJUST)) != 0 ||
2184 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 ||
2185 (r = sshpkt_put_u32(ssh, c->local_consumed)) != 0 ||
2186 (r = sshpkt_send(ssh)) != 0) {
2187 fatal("%s: channel %i: %s", __func__,
2188 c->self, ssh_err(r));
2189 }
2190 debug2("channel %d: window %d sent adjust %d",
2191 c->self, c->local_window,
2192 c->local_consumed);
2193 c->local_window += c->local_consumed;
2194 c->local_consumed = 0;
2195 }
2196 return 1;
2197 }
2198
2199 static void
2200 channel_post_open(struct ssh *ssh, Channel *c,
2201 fd_set *readset, fd_set *writeset)
2202 {
2203 channel_handle_rfd(ssh, c, readset, writeset);
2204 channel_handle_wfd(ssh, c, readset, writeset);
2205 channel_handle_efd(ssh, c, readset, writeset);
2206 channel_check_window(ssh, c);
2207 }
2208
2209 static u_int
2210 read_mux(struct ssh *ssh, Channel *c, u_int need)
2211 {
2212 char buf[CHAN_RBUF];
2213 ssize_t len;
2214 u_int rlen;
2215 int r;
2216
2217 if (sshbuf_len(c->input) < need) {
2218 rlen = need - sshbuf_len(c->input);
2219 len = read(c->rfd, buf, MINIMUM(rlen, CHAN_RBUF));
2220 if (len == -1 && (errno == EINTR || errno == EAGAIN))
2221 return sshbuf_len(c->input);
2222 if (len <= 0) {
2223 debug2("channel %d: ctl read<=0 rfd %d len %zd",
2224 c->self, c->rfd, len);
2225 chan_read_failed(ssh, c);
2226 return 0;
2227 } else if ((r = sshbuf_put(c->input, buf, len)) != 0) {
2228 fatal("%s: channel %d: append: %s",
2229 __func__, c->self, ssh_err(r));
2230 }
2231 }
2232 return sshbuf_len(c->input);
2233 }
2234
2235 static void
2236 channel_post_mux_client_read(struct ssh *ssh, Channel *c,
2237 fd_set *readset, fd_set *writeset)
2238 {
2239 u_int need;
2240
2241 if (c->rfd == -1 || !FD_ISSET(c->rfd, readset))
2242 return;
2243 if (c->istate != CHAN_INPUT_OPEN && c->istate != CHAN_INPUT_WAIT_DRAIN)
2244 return;
2245 if (c->mux_pause)
2246 return;
2247
2248 /*
2249 * Don't not read past the precise end of packets to
2250 * avoid disrupting fd passing.
2251 */
2252 if (read_mux(ssh, c, 4) < 4) /* read header */
2253 return;
2254 /* XXX sshbuf_peek_u32 */
2255 need = PEEK_U32(sshbuf_ptr(c->input));
2256 #define CHANNEL_MUX_MAX_PACKET (256 * 1024)
2257 if (need > CHANNEL_MUX_MAX_PACKET) {
2258 debug2("channel %d: packet too big %u > %u",
2259 c->self, CHANNEL_MUX_MAX_PACKET, need);
2260 chan_rcvd_oclose(ssh, c);
2261 return;
2262 }
2263 if (read_mux(ssh, c, need + 4) < need + 4) /* read body */
2264 return;
2265 if (c->mux_rcb(ssh, c) != 0) {
2266 debug("channel %d: mux_rcb failed", c->self);
2267 chan_mark_dead(ssh, c);
2268 return;
2269 }
2270 }
2271
2272 static void
2273 channel_post_mux_client_write(struct ssh *ssh, Channel *c,
2274 fd_set *readset, fd_set *writeset)
2275 {
2276 ssize_t len;
2277 int r;
2278
2279 if (c->wfd == -1 || !FD_ISSET(c->wfd, writeset) ||
2280 sshbuf_len(c->output) == 0)
2281 return;
2282
2283 len = write(c->wfd, sshbuf_ptr(c->output), sshbuf_len(c->output));
2284 if (len == -1 && (errno == EINTR || errno == EAGAIN))
2285 return;
2286 if (len <= 0) {
2287 chan_mark_dead(ssh, c);
2288 return;
2289 }
2290 if ((r = sshbuf_consume(c->output, len)) != 0)
2291 fatal("%s: channel %d: consume: %s", __func__,
2292 c->self, ssh_err(r));
2293 }
2294
2295 static void
2296 channel_post_mux_client(struct ssh *ssh, Channel *c,
2297 fd_set *readset, fd_set *writeset)
2298 {
2299 channel_post_mux_client_read(ssh, c, readset, writeset);
2300 channel_post_mux_client_write(ssh, c, readset, writeset);
2301 }
2302
2303 static void
2304 channel_post_mux_listener(struct ssh *ssh, Channel *c,
2305 fd_set *readset, fd_set *writeset)
2306 {
2307 Channel *nc;
2308 struct sockaddr_storage addr;
2309 socklen_t addrlen;
2310 int newsock;
2311 uid_t euid;
2312 gid_t egid;
2313
2314 if (!FD_ISSET(c->sock, readset))
2315 return;
2316
2317 debug("multiplexing control connection");
2318
2319 /*
2320 * Accept connection on control socket
2321 */
2322 memset(&addr, 0, sizeof(addr));
2323 addrlen = sizeof(addr);
2324 if ((newsock = accept(c->sock, (struct sockaddr*)&addr,
2325 &addrlen)) == -1) {
2326 error("%s accept: %s", __func__, strerror(errno));
2327 if (errno == EMFILE || errno == ENFILE)
2328 c->notbefore = monotime() + 1;
2329 return;
2330 }
2331
2332 if (getpeereid(newsock, &euid, &egid) == -1) {
2333 error("%s getpeereid failed: %s", __func__,
2334 strerror(errno));
2335 close(newsock);
2336 return;
2337 }
2338 if ((euid != 0) && (getuid() != euid)) {
2339 error("multiplex uid mismatch: peer euid %u != uid %u",
2340 (u_int)euid, (u_int)getuid());
2341 close(newsock);
2342 return;
2343 }
2344 nc = channel_new(ssh, "multiplex client", SSH_CHANNEL_MUX_CLIENT,
2345 newsock, newsock, -1, c->local_window_max,
2346 c->local_maxpacket, 0, "mux-control", 1);
2347 nc->mux_rcb = c->mux_rcb;
2348 debug3("%s: new mux channel %d fd %d", __func__, nc->self, nc->sock);
2349 /* establish state */
2350 nc->mux_rcb(ssh, nc);
2351 /* mux state transitions must not elicit protocol messages */
2352 nc->flags |= CHAN_LOCAL;
2353 }
2354
2355 static void
2356 channel_handler_init(struct ssh_channels *sc)
2357 {
2358 chan_fn **pre, **post;
2359
2360 if ((pre = calloc(SSH_CHANNEL_MAX_TYPE, sizeof(*pre))) == NULL ||
2361 (post = calloc(SSH_CHANNEL_MAX_TYPE, sizeof(*post))) == NULL)
2362 fatal("%s: allocation failed", __func__);
2363
2364 pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
2365 pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
2366 pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
2367 pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
2368 pre[SSH_CHANNEL_UNIX_LISTENER] = &channel_pre_listener;
2369 pre[SSH_CHANNEL_RUNIX_LISTENER] = &channel_pre_listener;
2370 pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
2371 pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
2372 pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
2373 pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
2374 pre[SSH_CHANNEL_RDYNAMIC_FINISH] = &channel_pre_connecting;
2375 pre[SSH_CHANNEL_MUX_LISTENER] = &channel_pre_listener;
2376 pre[SSH_CHANNEL_MUX_CLIENT] = &channel_pre_mux_client;
2377
2378 post[SSH_CHANNEL_OPEN] = &channel_post_open;
2379 post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
2380 post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
2381 post[SSH_CHANNEL_UNIX_LISTENER] = &channel_post_port_listener;
2382 post[SSH_CHANNEL_RUNIX_LISTENER] = &channel_post_port_listener;
2383 post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
2384 post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
2385 post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
2386 post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
2387 post[SSH_CHANNEL_RDYNAMIC_FINISH] = &channel_post_connecting;
2388 post[SSH_CHANNEL_MUX_LISTENER] = &channel_post_mux_listener;
2389 post[SSH_CHANNEL_MUX_CLIENT] = &channel_post_mux_client;
2390
2391 sc->channel_pre = pre;
2392 sc->channel_post = post;
2393 }
2394
2395 /* gc dead channels */
2396 static void
2397 channel_garbage_collect(struct ssh *ssh, Channel *c)
2398 {
2399 if (c == NULL)
2400 return;
2401 if (c->detach_user != NULL) {
2402 if (!chan_is_dead(ssh, c, c->detach_close))
2403 return;
2404
2405 debug2("channel %d: gc: notify user", c->self);
2406 c->detach_user(ssh, c->self, NULL);
2407 /* if we still have a callback */
2408 if (c->detach_user != NULL)
2409 return;
2410 debug2("channel %d: gc: user detached", c->self);
2411 }
2412 if (!chan_is_dead(ssh, c, 1))
2413 return;
2414 debug2("channel %d: garbage collecting", c->self);
2415 channel_free(ssh, c);
2416 }
2417
2418 enum channel_table { CHAN_PRE, CHAN_POST };
2419
2420 static void
2421 channel_handler(struct ssh *ssh, int table,
2422 fd_set *readset, fd_set *writeset, time_t *unpause_secs)
2423 {
2424 struct ssh_channels *sc = ssh->chanctxt;
2425 chan_fn **ftab = table == CHAN_PRE ? sc->channel_pre : sc->channel_post;
2426 u_int i, oalloc;
2427 Channel *c;
2428 time_t now;
2429
2430 now = monotime();
2431 if (unpause_secs != NULL)
2432 *unpause_secs = 0;
2433 for (i = 0, oalloc = sc->channels_alloc; i < oalloc; i++) {
2434 c = sc->channels[i];
2435 if (c == NULL)
2436 continue;
2437 if (c->delayed) {
2438 if (table == CHAN_PRE)
2439 c->delayed = 0;
2440 else
2441 continue;
2442 }
2443 if (ftab[c->type] != NULL) {
2444 /*
2445 * Run handlers that are not paused.
2446 */
2447 if (c->notbefore <= now)
2448 (*ftab[c->type])(ssh, c, readset, writeset);
2449 else if (unpause_secs != NULL) {
2450 /*
2451 * Collect the time that the earliest
2452 * channel comes off pause.
2453 */
2454 debug3("%s: chan %d: skip for %d more seconds",
2455 __func__, c->self,
2456 (int)(c->notbefore - now));
2457 if (*unpause_secs == 0 ||
2458 (c->notbefore - now) < *unpause_secs)
2459 *unpause_secs = c->notbefore - now;
2460 }
2461 }
2462 channel_garbage_collect(ssh, c);
2463 }
2464 if (unpause_secs != NULL && *unpause_secs != 0)
2465 debug3("%s: first channel unpauses in %d seconds",
2466 __func__, (int)*unpause_secs);
2467 }
2468
2469 /*
2470 * Create sockets before allocating the select bitmasks.
2471 * This is necessary for things that need to happen after reading
2472 * the network-input but before channel_prepare_select().
2473 */
2474 static void
2475 channel_before_prepare_select(struct ssh *ssh)
2476 {
2477 struct ssh_channels *sc = ssh->chanctxt;
2478 Channel *c;
2479 u_int i, oalloc;
2480
2481 for (i = 0, oalloc = sc->channels_alloc; i < oalloc; i++) {
2482 c = sc->channels[i];
2483 if (c == NULL)
2484 continue;
2485 if (c->type == SSH_CHANNEL_RDYNAMIC_OPEN)
2486 channel_before_prepare_select_rdynamic(ssh, c);
2487 }
2488 }
2489
2490 /*
2491 * Allocate/update select bitmasks and add any bits relevant to channels in
2492 * select bitmasks.
2493 */
2494 void
2495 channel_prepare_select(struct ssh *ssh, fd_set **readsetp, fd_set **writesetp,
2496 int *maxfdp, u_int *nallocp, time_t *minwait_secs)
2497 {
2498 u_int n, sz, nfdset;
2499
2500 channel_before_prepare_select(ssh); /* might update channel_max_fd */
2501
2502 n = MAXIMUM(*maxfdp, ssh->chanctxt->channel_max_fd);
2503
2504 nfdset = howmany(n+1, NFDBITS);
2505 /* Explicitly test here, because xrealloc isn't always called */
2506 if (nfdset && SIZE_MAX / nfdset < sizeof(fd_mask))
2507 fatal("channel_prepare_select: max_fd (%d) is too large", n);
2508 sz = nfdset * sizeof(fd_mask);
2509
2510 /* perhaps check sz < nalloc/2 and shrink? */
2511 if (*readsetp == NULL || sz > *nallocp) {
2512 *readsetp = xreallocarray(*readsetp, nfdset, sizeof(fd_mask));
2513 *writesetp = xreallocarray(*writesetp, nfdset, sizeof(fd_mask));
2514 *nallocp = sz;
2515 }
2516 *maxfdp = n;
2517 memset(*readsetp, 0, sz);
2518 memset(*writesetp, 0, sz);
2519
2520 if (!ssh_packet_is_rekeying(ssh))
2521 channel_handler(ssh, CHAN_PRE, *readsetp, *writesetp,
2522 minwait_secs);
2523 }
2524
2525 /*
2526 * After select, perform any appropriate operations for channels which have
2527 * events pending.
2528 */
2529 void
2530 channel_after_select(struct ssh *ssh, fd_set *readset, fd_set *writeset)
2531 {
2532 channel_handler(ssh, CHAN_POST, readset, writeset, NULL);
2533 }
2534
2535 /*
2536 * Enqueue data for channels with open or draining c->input.
2537 */
2538 static void
2539 channel_output_poll_input_open(struct ssh *ssh, Channel *c)
2540 {
2541 size_t len, plen;
2542 const u_char *pkt;
2543 int r;
2544
2545 if ((len = sshbuf_len(c->input)) == 0) {
2546 if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
2547 /*
2548 * input-buffer is empty and read-socket shutdown:
2549 * tell peer, that we will not send more data:
2550 * send IEOF.
2551 * hack for extended data: delay EOF if EFD still
2552 * in use.
2553 */
2554 if (CHANNEL_EFD_INPUT_ACTIVE(c))
2555 debug2("channel %d: "
2556 "ibuf_empty delayed efd %d/(%zu)",
2557 c->self, c->efd, sshbuf_len(c->extended));
2558 else
2559 chan_ibuf_empty(ssh, c);
2560 }
2561 return;
2562 }
2563
2564 if (!c->have_remote_id)
2565 fatal(":%s: channel %d: no remote id", __func__, c->self);
2566
2567 if (c->datagram) {
2568 /* Check datagram will fit; drop if not */
2569 if ((r = sshbuf_get_string_direct(c->input, &pkt, &plen)) != 0)
2570 fatal("%s: channel %d: get datagram: %s", __func__,
2571 c->self, ssh_err(r));
2572 /*
2573 * XXX this does tail-drop on the datagram queue which is
2574 * usually suboptimal compared to head-drop. Better to have
2575 * backpressure at read time? (i.e. read + discard)
2576 */
2577 if (plen > c->remote_window || plen > c->remote_maxpacket) {
2578 debug("channel %d: datagram too big", c->self);
2579 return;
2580 }
2581 /* Enqueue it */
2582 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 ||
2583 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 ||
2584 (r = sshpkt_put_string(ssh, pkt, plen)) != 0 ||
2585 (r = sshpkt_send(ssh)) != 0) {
2586 fatal("%s: channel %i: datagram: %s", __func__,
2587 c->self, ssh_err(r));
2588 }
2589 c->remote_window -= plen;
2590 return;
2591 }
2592
2593 /* Enqueue packet for buffered data. */
2594 if (len > c->remote_window)
2595 len = c->remote_window;
2596 if (len > c->remote_maxpacket)
2597 len = c->remote_maxpacket;
2598 if (len == 0)
2599 return;
2600 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 ||
2601 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 ||
2602 (r = sshpkt_put_string(ssh, sshbuf_ptr(c->input), len)) != 0 ||
2603 (r = sshpkt_send(ssh)) != 0) {
2604 fatal("%s: channel %i: data: %s", __func__,
2605 c->self, ssh_err(r));
2606 }
2607 if ((r = sshbuf_consume(c->input, len)) != 0)
2608 fatal("%s: channel %i: consume: %s", __func__,
2609 c->self, ssh_err(r));
2610 c->remote_window -= len;
2611 }
2612
2613 /*
2614 * Enqueue data for channels with open c->extended in read mode.
2615 */
2616 static void
2617 channel_output_poll_extended_read(struct ssh *ssh, Channel *c)
2618 {
2619 size_t len;
2620 int r;
2621
2622 if ((len = sshbuf_len(c->extended)) == 0)
2623 return;
2624
2625 debug2("channel %d: rwin %u elen %zu euse %d", c->self,
2626 c->remote_window, sshbuf_len(c->extended), c->extended_usage);
2627 if (len > c->remote_window)
2628 len = c->remote_window;
2629 if (len > c->remote_maxpacket)
2630 len = c->remote_maxpacket;
2631 if (len == 0)
2632 return;
2633 if (!c->have_remote_id)
2634 fatal(":%s: channel %d: no remote id", __func__, c->self);
2635 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_EXTENDED_DATA)) != 0 ||
2636 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 ||
2637 (r = sshpkt_put_u32(ssh, SSH2_EXTENDED_DATA_STDERR)) != 0 ||
2638 (r = sshpkt_put_string(ssh, sshbuf_ptr(c->extended), len)) != 0 ||
2639 (r = sshpkt_send(ssh)) != 0) {
2640 fatal("%s: channel %i: data: %s", __func__,
2641 c->self, ssh_err(r));
2642 }
2643 if ((r = sshbuf_consume(c->extended, len)) != 0)
2644 fatal("%s: channel %i: consume: %s", __func__,
2645 c->self, ssh_err(r));
2646 c->remote_window -= len;
2647 debug2("channel %d: sent ext data %zu", c->self, len);
2648 }
2649
2650 /* If there is data to send to the connection, enqueue some of it now. */
2651 void
2652 channel_output_poll(struct ssh *ssh)
2653 {
2654 struct ssh_channels *sc = ssh->chanctxt;
2655 Channel *c;
2656 u_int i;
2657
2658 for (i = 0; i < sc->channels_alloc; i++) {
2659 c = sc->channels[i];
2660 if (c == NULL)
2661 continue;
2662
2663 /*
2664 * We are only interested in channels that can have buffered
2665 * incoming data.
2666 */
2667 if (c->type != SSH_CHANNEL_OPEN)
2668 continue;
2669 if ((c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
2670 /* XXX is this true? */
2671 debug3("channel %d: will not send data after close",
2672 c->self);
2673 continue;
2674 }
2675
2676 /* Get the amount of buffered data for this channel. */
2677 if (c->istate == CHAN_INPUT_OPEN ||
2678 c->istate == CHAN_INPUT_WAIT_DRAIN)
2679 channel_output_poll_input_open(ssh, c);
2680 /* Send extended data, i.e. stderr */
2681 if (!(c->flags & CHAN_EOF_SENT) &&
2682 c->extended_usage == CHAN_EXTENDED_READ)
2683 channel_output_poll_extended_read(ssh, c);
2684 }
2685 }
2686
2687 /* -- mux proxy support */
2688
2689 /*
2690 * When multiplexing channel messages for mux clients we have to deal
2691 * with downstream messages from the mux client and upstream messages
2692 * from the ssh server:
2693 * 1) Handling downstream messages is straightforward and happens
2694 * in channel_proxy_downstream():
2695 * - We forward all messages (mostly) unmodified to the server.
2696 * - However, in order to route messages from upstream to the correct
2697 * downstream client, we have to replace the channel IDs used by the
2698 * mux clients with a unique channel ID because the mux clients might
2699 * use conflicting channel IDs.
2700 * - so we inspect and change both SSH2_MSG_CHANNEL_OPEN and
2701 * SSH2_MSG_CHANNEL_OPEN_CONFIRMATION messages, create a local
2702 * SSH_CHANNEL_MUX_PROXY channel and replace the mux clients ID
2703 * with the newly allocated channel ID.
2704 * 2) Upstream messages are received by matching SSH_CHANNEL_MUX_PROXY
2705 * channels and processed by channel_proxy_upstream(). The local channel ID
2706 * is then translated back to the original mux client ID.
2707 * 3) In both cases we need to keep track of matching SSH2_MSG_CHANNEL_CLOSE
2708 * messages so we can clean up SSH_CHANNEL_MUX_PROXY channels.
2709 * 4) The SSH_CHANNEL_MUX_PROXY channels also need to closed when the
2710 * downstream mux client are removed.
2711 * 5) Handling SSH2_MSG_CHANNEL_OPEN messages from the upstream server
2712 * requires more work, because they are not addressed to a specific
2713 * channel. E.g. client_request_forwarded_tcpip() needs to figure
2714 * out whether the request is addressed to the local client or a
2715 * specific downstream client based on the listen-address/port.
2716 * 6) Agent and X11-Forwarding have a similar problem and are currently
2717 * not supported as the matching session/channel cannot be identified
2718 * easily.
2719 */
2720
2721 /*
2722 * receive packets from downstream mux clients:
2723 * channel callback fired on read from mux client, creates
2724 * SSH_CHANNEL_MUX_PROXY channels and translates channel IDs
2725 * on channel creation.
2726 */
2727 int
2728 channel_proxy_downstream(struct ssh *ssh, Channel *downstream)
2729 {
2730 Channel *c = NULL;
2731 struct sshbuf *original = NULL, *modified = NULL;
2732 const u_char *cp;
2733 char *ctype = NULL, *listen_host = NULL;
2734 u_char type;
2735 size_t have;
2736 int ret = -1, r;
2737 u_int id, remote_id, listen_port;
2738
2739 /* sshbuf_dump(downstream->input, stderr); */
2740 if ((r = sshbuf_get_string_direct(downstream->input, &cp, &have))
2741 != 0) {
2742 error("%s: malformed message: %s", __func__, ssh_err(r));
2743 return -1;
2744 }
2745 if (have < 2) {
2746 error("%s: short message", __func__);
2747 return -1;
2748 }
2749 type = cp[1];
2750 /* skip padlen + type */
2751 cp += 2;
2752 have -= 2;
2753 if (ssh_packet_log_type(type))
2754 debug3("%s: channel %u: down->up: type %u", __func__,
2755 downstream->self, type);
2756
2757 switch (type) {
2758 case SSH2_MSG_CHANNEL_OPEN:
2759 if ((original = sshbuf_from(cp, have)) == NULL ||
2760 (modified = sshbuf_new()) == NULL) {
2761 error("%s: alloc", __func__);
2762 goto out;
2763 }
2764 if ((r = sshbuf_get_cstring(original, &ctype, NULL)) != 0 ||
2765 (r = sshbuf_get_u32(original, &id)) != 0) {
2766 error("%s: parse error %s", __func__, ssh_err(r));
2767 goto out;
2768 }
2769 c = channel_new(ssh, "mux proxy", SSH_CHANNEL_MUX_PROXY,
2770 -1, -1, -1, 0, 0, 0, ctype, 1);
2771 c->mux_ctx = downstream; /* point to mux client */
2772 c->mux_downstream_id = id; /* original downstream id */
2773 if ((r = sshbuf_put_cstring(modified, ctype)) != 0 ||
2774 (r = sshbuf_put_u32(modified, c->self)) != 0 ||
2775 (r = sshbuf_putb(modified, original)) != 0) {
2776 error("%s: compose error %s", __func__, ssh_err(r));
2777 channel_free(ssh, c);
2778 goto out;
2779 }
2780 break;
2781 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION:
2782 /*
2783 * Almost the same as SSH2_MSG_CHANNEL_OPEN, except then we
2784 * need to parse 'remote_id' instead of 'ctype'.
2785 */
2786 if ((original = sshbuf_from(cp, have)) == NULL ||
2787 (modified = sshbuf_new()) == NULL) {
2788 error("%s: alloc", __func__);
2789 goto out;
2790 }
2791 if ((r = sshbuf_get_u32(original, &remote_id)) != 0 ||
2792 (r = sshbuf_get_u32(original, &id)) != 0) {
2793 error("%s: parse error %s", __func__, ssh_err(r));
2794 goto out;
2795 }
2796 c = channel_new(ssh, "mux proxy", SSH_CHANNEL_MUX_PROXY,
2797 -1, -1, -1, 0, 0, 0, "mux-down-connect", 1);
2798 c->mux_ctx = downstream; /* point to mux client */
2799 c->mux_downstream_id = id;
2800 c->remote_id = remote_id;
2801 c->have_remote_id = 1;
2802 if ((r = sshbuf_put_u32(modified, remote_id)) != 0 ||
2803 (r = sshbuf_put_u32(modified, c->self)) != 0 ||
2804 (r = sshbuf_putb(modified, original)) != 0) {
2805 error("%s: compose error %s", __func__, ssh_err(r));
2806 channel_free(ssh, c);
2807 goto out;
2808 }
2809 break;
2810 case SSH2_MSG_GLOBAL_REQUEST:
2811 if ((original = sshbuf_from(cp, have)) == NULL) {
2812 error("%s: alloc", __func__);
2813 goto out;
2814 }
2815 if ((r = sshbuf_get_cstring(original, &ctype, NULL)) != 0) {
2816 error("%s: parse error %s", __func__, ssh_err(r));
2817 goto out;
2818 }
2819 if (strcmp(ctype, "tcpip-forward") != 0) {
2820 error("%s: unsupported request %s", __func__, ctype);
2821 goto out;
2822 }
2823 if ((r = sshbuf_get_u8(original, NULL)) != 0 ||
2824 (r = sshbuf_get_cstring(original, &listen_host, NULL)) != 0 ||
2825 (r = sshbuf_get_u32(original, &listen_port)) != 0) {
2826 error("%s: parse error %s", __func__, ssh_err(r));
2827 goto out;
2828 }
2829 if (listen_port > 65535) {
2830 error("%s: tcpip-forward for %s: bad port %u",
2831 __func__, listen_host, listen_port);
2832 goto out;
2833 }
2834 /* Record that connection to this host/port is permitted. */
2835 permission_set_add(ssh, FORWARD_USER, FORWARD_LOCAL, "<mux>", -1,
2836 listen_host, NULL, (int)listen_port, downstream);
2837 listen_host = NULL;
2838 break;
2839 case SSH2_MSG_CHANNEL_CLOSE:
2840 if (have < 4)
2841 break;
2842 remote_id = PEEK_U32(cp);
2843 if ((c = channel_by_remote_id(ssh, remote_id)) != NULL) {
2844 if (c->flags & CHAN_CLOSE_RCVD)
2845 channel_free(ssh, c);
2846 else
2847 c->flags |= CHAN_CLOSE_SENT;
2848 }
2849 break;
2850 }
2851 if (modified) {
2852 if ((r = sshpkt_start(ssh, type)) != 0 ||
2853 (r = sshpkt_putb(ssh, modified)) != 0 ||
2854 (r = sshpkt_send(ssh)) != 0) {
2855 error("%s: send %s", __func__, ssh_err(r));
2856 goto out;
2857 }
2858 } else {
2859 if ((r = sshpkt_start(ssh, type)) != 0 ||
2860 (r = sshpkt_put(ssh, cp, have)) != 0 ||
2861 (r = sshpkt_send(ssh)) != 0) {
2862 error("%s: send %s", __func__, ssh_err(r));
2863 goto out;
2864 }
2865 }
2866 ret = 0;
2867 out:
2868 free(ctype);
2869 free(listen_host);
2870 sshbuf_free(original);
2871 sshbuf_free(modified);
2872 return ret;
2873 }
2874
2875 /*
2876 * receive packets from upstream server and de-multiplex packets
2877 * to correct downstream:
2878 * implemented as a helper for channel input handlers,
2879 * replaces local (proxy) channel ID with downstream channel ID.
2880 */
2881 int
2882 channel_proxy_upstream(Channel *c, int type, u_int32_t seq, struct ssh *ssh)
2883 {
2884 struct sshbuf *b = NULL;
2885 Channel *downstream;
2886 const u_char *cp = NULL;
2887 size_t len;
2888 int r;
2889
2890 /*
2891 * When receiving packets from the peer we need to check whether we
2892 * need to forward the packets to the mux client. In this case we
2893 * restore the original channel id and keep track of CLOSE messages,
2894 * so we can cleanup the channel.
2895 */
2896 if (c == NULL || c->type != SSH_CHANNEL_MUX_PROXY)
2897 return 0;
2898 if ((downstream = c->mux_ctx) == NULL)
2899 return 0;
2900 switch (type) {
2901 case SSH2_MSG_CHANNEL_CLOSE:
2902 case SSH2_MSG_CHANNEL_DATA:
2903 case SSH2_MSG_CHANNEL_EOF:
2904 case SSH2_MSG_CHANNEL_EXTENDED_DATA:
2905 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION:
2906 case SSH2_MSG_CHANNEL_OPEN_FAILURE:
2907 case SSH2_MSG_CHANNEL_WINDOW_ADJUST:
2908 case SSH2_MSG_CHANNEL_SUCCESS:
2909 case SSH2_MSG_CHANNEL_FAILURE:
2910 case SSH2_MSG_CHANNEL_REQUEST:
2911 break;
2912 default:
2913 debug2("%s: channel %u: unsupported type %u", __func__,
2914 c->self, type);
2915 return 0;
2916 }
2917 if ((b = sshbuf_new()) == NULL) {
2918 error("%s: alloc reply", __func__);
2919 goto out;
2920 }
2921 /* get remaining payload (after id) */
2922 cp = sshpkt_ptr(ssh, &len);
2923 if (cp == NULL) {
2924 error("%s: no packet", __func__);
2925 goto out;
2926 }
2927 /* translate id and send to muxclient */
2928 if ((r = sshbuf_put_u8(b, 0)) != 0 || /* padlen */
2929 (r = sshbuf_put_u8(b, type)) != 0 ||
2930 (r = sshbuf_put_u32(b, c->mux_downstream_id)) != 0 ||
2931 (r = sshbuf_put(b, cp, len)) != 0 ||
2932 (r = sshbuf_put_stringb(downstream->output, b)) != 0) {
2933 error("%s: compose for muxclient %s", __func__, ssh_err(r));
2934 goto out;
2935 }
2936 /* sshbuf_dump(b, stderr); */
2937 if (ssh_packet_log_type(type))
2938 debug3("%s: channel %u: up->down: type %u", __func__, c->self,
2939 type);
2940 out:
2941 /* update state */
2942 switch (type) {
2943 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION:
2944 /* record remote_id for SSH2_MSG_CHANNEL_CLOSE */
2945 if (cp && len > 4) {
2946 c->remote_id = PEEK_U32(cp);
2947 c->have_remote_id = 1;
2948 }
2949 break;
2950 case SSH2_MSG_CHANNEL_CLOSE:
2951 if (c->flags & CHAN_CLOSE_SENT)
2952 channel_free(ssh, c);
2953 else
2954 c->flags |= CHAN_CLOSE_RCVD;
2955 break;
2956 }
2957 sshbuf_free(b);
2958 return 1;
2959 }
2960
2961 /* -- protocol input */
2962
2963 /* Parse a channel ID from the current packet */
2964 static int
2965 channel_parse_id(struct ssh *ssh, const char *where, const char *what)
2966 {
2967 u_int32_t id;
2968 int r;
2969
2970 if ((r = sshpkt_get_u32(ssh, &id)) != 0) {
2971 error("%s: parse id: %s", where, ssh_err(r));
2972 ssh_packet_disconnect(ssh, "Invalid %s message", what);
2973 }
2974 if (id > INT_MAX) {
2975 error("%s: bad channel id %u: %s", where, id, ssh_err(r));
2976 ssh_packet_disconnect(ssh, "Invalid %s channel id", what);
2977 }
2978 return (int)id;
2979 }
2980
2981 /* Lookup a channel from an ID in the current packet */
2982 static Channel *
2983 channel_from_packet_id(struct ssh *ssh, const char *where, const char *what)
2984 {
2985 int id = channel_parse_id(ssh, where, what);
2986 Channel *c;
2987
2988 if ((c = channel_lookup(ssh, id)) == NULL) {
2989 ssh_packet_disconnect(ssh,
2990 "%s packet referred to nonexistent channel %d", what, id);
2991 }
2992 return c;
2993 }
2994
2995 int
2996 channel_input_data(int type, u_int32_t seq, struct ssh *ssh)
2997 {
2998 const u_char *data;
2999 size_t data_len, win_len;
3000 Channel *c = channel_from_packet_id(ssh, __func__, "data");
3001 int r;
3002
3003 if (channel_proxy_upstream(c, type, seq, ssh))
3004 return 0;
3005
3006 /* Ignore any data for non-open channels (might happen on close) */
3007 if (c->type != SSH_CHANNEL_OPEN &&
3008 c->type != SSH_CHANNEL_RDYNAMIC_OPEN &&
3009 c->type != SSH_CHANNEL_RDYNAMIC_FINISH &&
3010 c->type != SSH_CHANNEL_X11_OPEN)
3011 return 0;
3012
3013 /* Get the data. */
3014 if ((r = sshpkt_get_string_direct(ssh, &data, &data_len)) != 0 ||
3015 (r = sshpkt_get_end(ssh)) != 0)
3016 fatal("%s: channel %d: get data: %s", __func__,
3017 c->self, ssh_err(r));
3018
3019 win_len = data_len;
3020 if (c->datagram)
3021 win_len += 4; /* string length header */
3022
3023 /*
3024 * The sending side reduces its window as it sends data, so we
3025 * must 'fake' consumption of the data in order to ensure that window
3026 * updates are sent back. Otherwise the connection might deadlock.
3027 */
3028 if (c->ostate != CHAN_OUTPUT_OPEN) {
3029 c->local_window -= win_len;
3030 c->local_consumed += win_len;
3031 return 0;
3032 }
3033
3034 if (win_len > c->local_maxpacket) {
3035 logit("channel %d: rcvd big packet %zu, maxpack %u",
3036 c->self, win_len, c->local_maxpacket);
3037 return 0;
3038 }
3039 if (win_len > c->local_window) {
3040 logit("channel %d: rcvd too much data %zu, win %u",
3041 c->self, win_len, c->local_window);
3042 return 0;
3043 }
3044 c->local_window -= win_len;
3045
3046 if (c->datagram) {
3047 if ((r = sshbuf_put_string(c->output, data, data_len)) != 0)
3048 fatal("%s: channel %d: append datagram: %s",
3049 __func__, c->self, ssh_err(r));
3050 } else if ((r = sshbuf_put(c->output, data, data_len)) != 0)
3051 fatal("%s: channel %d: append data: %s",
3052 __func__, c->self, ssh_err(r));
3053
3054 return 0;
3055 }
3056
3057 int
3058 channel_input_extended_data(int type, u_int32_t seq, struct ssh *ssh)
3059 {
3060 const u_char *data;
3061 size_t data_len;
3062 u_int32_t tcode;
3063 Channel *c = channel_from_packet_id(ssh, __func__, "extended data");
3064 int r;
3065
3066 if (channel_proxy_upstream(c, type, seq, ssh))
3067 return 0;
3068 if (c->type != SSH_CHANNEL_OPEN) {
3069 logit("channel %d: ext data for non open", c->self);
3070 return 0;
3071 }
3072 if (c->flags & CHAN_EOF_RCVD) {
3073 if (datafellows & SSH_BUG_EXTEOF)
3074 debug("channel %d: accepting ext data after eof",
3075 c->self);
3076 else
3077 ssh_packet_disconnect(ssh, "Received extended_data "
3078 "after EOF on channel %d.", c->self);
3079 }
3080
3081 if ((r = sshpkt_get_u32(ssh, &tcode)) != 0) {
3082 error("%s: parse tcode: %s", __func__, ssh_err(r));
3083 ssh_packet_disconnect(ssh, "Invalid extended_data message");
3084 }
3085 if (c->efd == -1 ||
3086 c->extended_usage != CHAN_EXTENDED_WRITE ||
3087 tcode != SSH2_EXTENDED_DATA_STDERR) {
3088 logit("channel %d: bad ext data", c->self);
3089 return 0;
3090 }
3091 if ((r = sshpkt_get_string_direct(ssh, &data, &data_len)) != 0 ||
3092 (r = sshpkt_get_end(ssh)) != 0) {
3093 error("%s: parse data: %s", __func__, ssh_err(r));
3094 ssh_packet_disconnect(ssh, "Invalid extended_data message");
3095 }
3096
3097 if (data_len > c->local_window) {
3098 logit("channel %d: rcvd too much extended_data %zu, win %u",
3099 c->self, data_len, c->local_window);
3100 return 0;
3101 }
3102 debug2("channel %d: rcvd ext data %zu", c->self, data_len);
3103 /* XXX sshpkt_getb? */
3104 if ((r = sshbuf_put(c->extended, data, data_len)) != 0)
3105 error("%s: append: %s", __func__, ssh_err(r));
3106 c->local_window -= data_len;
3107 return 0;
3108 }
3109
3110 int
3111 channel_input_ieof(int type, u_int32_t seq, struct ssh *ssh)
3112 {
3113 Channel *c = channel_from_packet_id(ssh, __func__, "ieof");
3114 int r;
3115
3116 if ((r = sshpkt_get_end(ssh)) != 0) {
3117 error("%s: parse data: %s", __func__, ssh_err(r));
3118 ssh_packet_disconnect(ssh, "Invalid ieof message");
3119 }
3120
3121 if (channel_proxy_upstream(c, type, seq, ssh))
3122 return 0;
3123 chan_rcvd_ieof(ssh, c);
3124
3125 /* XXX force input close */
3126 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) {
3127 debug("channel %d: FORCE input drain", c->self);
3128 c->istate = CHAN_INPUT_WAIT_DRAIN;
3129 if (sshbuf_len(c->input) == 0)
3130 chan_ibuf_empty(ssh, c);
3131 }
3132 return 0;
3133 }
3134
3135 int
3136 channel_input_oclose(int type, u_int32_t seq, struct ssh *ssh)
3137 {
3138 Channel *c = channel_from_packet_id(ssh, __func__, "oclose");
3139 int r;
3140
3141 if (channel_proxy_upstream(c, type, seq, ssh))
3142 return 0;
3143 if ((r = sshpkt_get_end(ssh)) != 0) {
3144 error("%s: parse data: %s", __func__, ssh_err(r));
3145 ssh_packet_disconnect(ssh, "Invalid oclose message");
3146 }
3147 chan_rcvd_oclose(ssh, c);
3148 return 0;
3149 }
3150
3151 int
3152 channel_input_open_confirmation(int type, u_int32_t seq, struct ssh *ssh)
3153 {
3154 Channel *c = channel_from_packet_id(ssh, __func__, "open confirmation");
3155 u_int32_t remote_window, remote_maxpacket;
3156 int r;
3157
3158 if (channel_proxy_upstream(c, type, seq, ssh))
3159 return 0;
3160 if (c->type != SSH_CHANNEL_OPENING)
3161 ssh_packet_disconnect(ssh, "Received open confirmation for "
3162 "non-opening channel %d.", c->self);
3163 /*
3164 * Record the remote channel number and mark that the channel
3165 * is now open.
3166 */
3167 if ((r = sshpkt_get_u32(ssh, &c->remote_id)) != 0 ||
3168 (r = sshpkt_get_u32(ssh, &remote_window)) != 0 ||
3169 (r = sshpkt_get_u32(ssh, &remote_maxpacket)) != 0 ||
3170 (r = sshpkt_get_end(ssh)) != 0) {
3171 error("%s: window/maxpacket: %s", __func__, ssh_err(r));
3172 ssh_packet_disconnect(ssh, "Invalid open confirmation message");
3173 }
3174
3175 c->have_remote_id = 1;
3176 c->remote_window = remote_window;
3177 c->remote_maxpacket = remote_maxpacket;
3178 c->type = SSH_CHANNEL_OPEN;
3179 if (c->open_confirm) {
3180 debug2("%s: channel %d: callback start", __func__, c->self);
3181 c->open_confirm(ssh, c->self, 1, c->open_confirm_ctx);
3182 debug2("%s: channel %d: callback done", __func__, c->self);
3183 }
3184 debug2("channel %d: open confirm rwindow %u rmax %u", c->self,
3185 c->remote_window, c->remote_maxpacket);
3186 return 0;
3187 }
3188
3189 static char *
3190 reason2txt(int reason)
3191 {
3192 switch (reason) {
3193 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
3194 return "administratively prohibited";
3195 case SSH2_OPEN_CONNECT_FAILED:
3196 return "connect failed";
3197 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
3198 return "unknown channel type";
3199 case SSH2_OPEN_RESOURCE_SHORTAGE:
3200 return "resource shortage";
3201 }
3202 return "unknown reason";
3203 }
3204
3205 int
3206 channel_input_open_failure(int type, u_int32_t seq, struct ssh *ssh)
3207 {
3208 Channel *c = channel_from_packet_id(ssh, __func__, "open failure");
3209 u_int32_t reason;
3210 char *msg = NULL;
3211 int r;
3212
3213 if (channel_proxy_upstream(c, type, seq, ssh))
3214 return 0;
3215 if (c->type != SSH_CHANNEL_OPENING)
3216 ssh_packet_disconnect(ssh, "Received open failure for "
3217 "non-opening channel %d.", c->self);
3218 if ((r = sshpkt_get_u32(ssh, &reason)) != 0) {
3219 error("%s: reason: %s", __func__, ssh_err(r));
3220 ssh_packet_disconnect(ssh, "Invalid open failure message");
3221 }
3222 /* skip language */
3223 if ((r = sshpkt_get_cstring(ssh, &msg, NULL)) != 0 ||
3224 (r = sshpkt_get_string_direct(ssh, NULL, NULL)) != 0 ||
3225 (r = sshpkt_get_end(ssh)) != 0) {
3226 error("%s: message/lang: %s", __func__, ssh_err(r));
3227 ssh_packet_disconnect(ssh, "Invalid open failure message");
3228 }
3229 logit("channel %d: open failed: %s%s%s", c->self,
3230 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
3231 free(msg);
3232 if (c->open_confirm) {
3233 debug2("%s: channel %d: callback start", __func__, c->self);
3234 c->open_confirm(ssh, c->self, 0, c->open_confirm_ctx);
3235 debug2("%s: channel %d: callback done", __func__, c->self);
3236 }
3237 /* Schedule the channel for cleanup/deletion. */
3238 chan_mark_dead(ssh, c);
3239 return 0;
3240 }
3241
3242 int
3243 channel_input_window_adjust(int type, u_int32_t seq, struct ssh *ssh)
3244 {
3245 int id = channel_parse_id(ssh, __func__, "window adjust");
3246 Channel *c;
3247 u_int32_t adjust;
3248 u_int new_rwin;
3249 int r;
3250
3251 if ((c = channel_lookup(ssh, id)) == NULL) {
3252 logit("Received window adjust for non-open channel %d.", id);
3253 return 0;
3254 }
3255
3256 if (channel_proxy_upstream(c, type, seq, ssh))
3257 return 0;
3258 if ((r = sshpkt_get_u32(ssh, &adjust)) != 0 ||
3259 (r = sshpkt_get_end(ssh)) != 0) {
3260 error("%s: adjust: %s", __func__, ssh_err(r));
3261 ssh_packet_disconnect(ssh, "Invalid window adjust message");
3262 }
3263 debug2("channel %d: rcvd adjust %u", c->self, adjust);
3264 if ((new_rwin = c->remote_window + adjust) < c->remote_window) {
3265 fatal("channel %d: adjust %u overflows remote window %u",
3266 c->self, adjust, c->remote_window);
3267 }
3268 c->remote_window = new_rwin;
3269 return 0;
3270 }
3271
3272 int
3273 channel_input_status_confirm(int type, u_int32_t seq, struct ssh *ssh)
3274 {
3275 int id = channel_parse_id(ssh, __func__, "status confirm");
3276 Channel *c;
3277 struct channel_confirm *cc;
3278
3279 /* Reset keepalive timeout */
3280 ssh_packet_set_alive_timeouts(ssh, 0);
3281
3282 debug2("%s: type %d id %d", __func__, type, id);
3283
3284 if ((c = channel_lookup(ssh, id)) == NULL) {
3285 logit("%s: %d: unknown", __func__, id);
3286 return 0;
3287 }
3288 if (channel_proxy_upstream(c, type, seq, ssh))
3289 return 0;
3290 if (sshpkt_get_end(ssh) != 0)
3291 ssh_packet_disconnect(ssh, "Invalid status confirm message");
3292 if ((cc = TAILQ_FIRST(&c->status_confirms)) == NULL)
3293 return 0;
3294 cc->cb(ssh, type, c, cc->ctx);
3295 TAILQ_REMOVE(&c->status_confirms, cc, entry);
3296 freezero(cc, sizeof(*cc));
3297 return 0;
3298 }
3299
3300 /* -- tcp forwarding */
3301
3302 void
3303 channel_set_af(struct ssh *ssh, int af)
3304 {
3305 ssh->chanctxt->IPv4or6 = af;
3306 }
3307
3308
3309 /*
3310 * Determine whether or not a port forward listens to loopback, the
3311 * specified address or wildcard. On the client, a specified bind
3312 * address will always override gateway_ports. On the server, a
3313 * gateway_ports of 1 (``yes'') will override the client's specification
3314 * and force a wildcard bind, whereas a value of 2 (``clientspecified'')
3315 * will bind to whatever address the client asked for.
3316 *
3317 * Special-case listen_addrs are:
3318 *
3319 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR
3320 * "" (empty string), "*" -> wildcard v4/v6
3321 * "localhost" -> loopback v4/v6
3322 * "127.0.0.1" / "::1" -> accepted even if gateway_ports isn't set
3323 */
3324 static const char *
3325 channel_fwd_bind_addr(struct ssh *ssh, const char *listen_addr, int *wildcardp,
3326 int is_client, struct ForwardOptions *fwd_opts)
3327 {
3328 const char *addr = NULL;
3329 int wildcard = 0;
3330
3331 if (listen_addr == NULL) {
3332 /* No address specified: default to gateway_ports setting */
3333 if (fwd_opts->gateway_ports)
3334 wildcard = 1;
3335 } else if (fwd_opts->gateway_ports || is_client) {
3336 if (((datafellows & SSH_OLD_FORWARD_ADDR) &&
3337 strcmp(listen_addr, "0.0.0.0") == 0 && is_client == 0) ||
3338 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 ||
3339 (!is_client && fwd_opts->gateway_ports == 1)) {
3340 wildcard = 1;
3341 /*
3342 * Notify client if they requested a specific listen
3343 * address and it was overridden.
3344 */
3345 if (*listen_addr != '\0' &&
3346 strcmp(listen_addr, "0.0.0.0") != 0 &&
3347 strcmp(listen_addr, "*") != 0) {
3348 ssh_packet_send_debug(ssh,
3349 "Forwarding listen address "
3350 "\"%s\" overridden by server "
3351 "GatewayPorts", listen_addr);
3352 }
3353 } else if (strcmp(listen_addr, "localhost") != 0 ||
3354 strcmp(listen_addr, "127.0.0.1") == 0 ||
3355 strcmp(listen_addr, "::1") == 0) {
3356 /*
3357 * Accept explicit localhost address when
3358 * GatewayPorts=yes. The "localhost" hostname is
3359 * deliberately skipped here so it will listen on all
3360 * available local address families.
3361 */
3362 addr = listen_addr;
3363 }
3364 } else if (strcmp(listen_addr, "127.0.0.1") == 0 ||
3365 strcmp(listen_addr, "::1") == 0) {
3366 /*
3367 * If a specific IPv4/IPv6 localhost address has been
3368 * requested then accept it even if gateway_ports is in
3369 * effect. This allows the client to prefer IPv4 or IPv6.
3370 */
3371 addr = listen_addr;
3372 }
3373 if (wildcardp != NULL)
3374 *wildcardp = wildcard;
3375 return addr;
3376 }
3377
3378 static int
3379 channel_setup_fwd_listener_tcpip(struct ssh *ssh, int type,
3380 struct Forward *fwd, int *allocated_listen_port,
3381 struct ForwardOptions *fwd_opts)
3382 {
3383 Channel *c;
3384 int sock, r, success = 0, wildcard = 0, is_client;
3385 struct addrinfo hints, *ai, *aitop;
3386 const char *host, *addr;
3387 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
3388 in_port_t *lport_p;
3389
3390 is_client = (type == SSH_CHANNEL_PORT_LISTENER);
3391
3392 if (is_client && fwd->connect_path != NULL) {
3393 host = fwd->connect_path;
3394 } else {
3395 host = (type == SSH_CHANNEL_RPORT_LISTENER) ?
3396 fwd->listen_host : fwd->connect_host;
3397 if (host == NULL) {
3398 error("No forward host name.");
3399 return 0;
3400 }
3401 if (strlen(host) >= NI_MAXHOST) {
3402 error("Forward host name too long.");
3403 return 0;
3404 }
3405 }
3406
3407 /* Determine the bind address, cf. channel_fwd_bind_addr() comment */
3408 addr = channel_fwd_bind_addr(ssh, fwd->listen_host, &wildcard,
3409 is_client, fwd_opts);
3410 debug3("%s: type %d wildcard %d addr %s", __func__,
3411 type, wildcard, (addr == NULL) ? "NULL" : addr);
3412
3413 /*
3414 * getaddrinfo returns a loopback address if the hostname is
3415 * set to NULL and hints.ai_flags is not AI_PASSIVE
3416 */
3417 memset(&hints, 0, sizeof(hints));
3418 hints.ai_family = ssh->chanctxt->IPv4or6;
3419 hints.ai_flags = wildcard ? AI_PASSIVE : 0;
3420 hints.ai_socktype = SOCK_STREAM;
3421 snprintf(strport, sizeof strport, "%d", fwd->listen_port);
3422 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) {
3423 if (addr == NULL) {
3424 /* This really shouldn't happen */
3425 ssh_packet_disconnect(ssh, "getaddrinfo: fatal error: %s",
3426 ssh_gai_strerror(r));
3427 } else {
3428 error("%s: getaddrinfo(%.64s): %s", __func__, addr,
3429 ssh_gai_strerror(r));
3430 }
3431 return 0;
3432 }
3433 if (allocated_listen_port != NULL)
3434 *allocated_listen_port = 0;
3435 for (ai = aitop; ai; ai = ai->ai_next) {
3436 switch (ai->ai_family) {
3437 case AF_INET:
3438 lport_p = &((struct sockaddr_in *)ai->ai_addr)->
3439 sin_port;
3440 break;
3441 case AF_INET6:
3442 lport_p = &((struct sockaddr_in6 *)ai->ai_addr)->
3443 sin6_port;
3444 break;
3445 default:
3446 continue;
3447 }
3448 /*
3449 * If allocating a port for -R forwards, then use the
3450 * same port for all address families.
3451 */
3452 if (type == SSH_CHANNEL_RPORT_LISTENER &&
3453 fwd->listen_port == 0 && allocated_listen_port != NULL &&
3454 *allocated_listen_port > 0)
3455 *lport_p = htons(*allocated_listen_port);
3456
3457 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
3458 strport, sizeof(strport),
3459 NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
3460 error("%s: getnameinfo failed", __func__);
3461 continue;
3462 }
3463 /* Create a port to listen for the host. */
3464 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
3465 if (sock == -1) {
3466 /* this is no error since kernel may not support ipv6 */
3467 verbose("socket [%s]:%s: %.100s", ntop, strport,
3468 strerror(errno));
3469 continue;
3470 }
3471
3472 set_reuseaddr(sock);
3473 if (ai->ai_family == AF_INET6)
3474 sock_set_v6only(sock);
3475
3476 debug("Local forwarding listening on %s port %s.",
3477 ntop, strport);
3478
3479 /* Bind the socket to the address. */
3480 if (bind(sock, ai->ai_addr, ai->ai_addrlen) == -1) {
3481 /*
3482 * address can be in if use ipv6 address is
3483 * already bound
3484 */
3485 if (!ai->ai_next)
3486 error("bind [%s]:%s: %.100s",
3487 ntop, strport, strerror(errno));
3488 else
3489 verbose("bind [%s]:%s: %.100s",
3490 ntop, strport, strerror(errno));
3491
3492 close(sock);
3493 continue;
3494 }
3495 /* Start listening for connections on the socket. */
3496 if (listen(sock, SSH_LISTEN_BACKLOG) == -1) {
3497 error("listen: %.100s", strerror(errno));
3498 error("listen [%s]:%s: %.100s", ntop, strport,
3499 strerror(errno));
3500 close(sock);
3501 continue;
3502 }
3503
3504 /*
3505 * fwd->listen_port == 0 requests a dynamically allocated port -
3506 * record what we got.
3507 */
3508 if (type == SSH_CHANNEL_RPORT_LISTENER &&
3509 fwd->listen_port == 0 &&
3510 allocated_listen_port != NULL &&
3511 *allocated_listen_port == 0) {
3512 *allocated_listen_port = get_local_port(sock);
3513 debug("Allocated listen port %d",
3514 *allocated_listen_port);
3515 }
3516
3517 /* Allocate a channel number for the socket. */
3518 c = channel_new(ssh, "port listener", type, sock, sock, -1,
3519 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
3520 0, "port listener", 1);
3521 c->path = xstrdup(host);
3522 c->host_port = fwd->connect_port;
3523 c->listening_addr = addr == NULL ? NULL : xstrdup(addr);
3524 if (fwd->listen_port == 0 && allocated_listen_port != NULL &&
3525 !(datafellows & SSH_BUG_DYNAMIC_RPORT))
3526 c->listening_port = *allocated_listen_port;
3527 else
3528 c->listening_port = fwd->listen_port;
3529 success = 1;
3530 }
3531 if (success == 0)
3532 error("%s: cannot listen to port: %d", __func__,
3533 fwd->listen_port);
3534 freeaddrinfo(aitop);
3535 return success;
3536 }
3537
3538 static int
3539 channel_setup_fwd_listener_streamlocal(struct ssh *ssh, int type,
3540 struct Forward *fwd, struct ForwardOptions *fwd_opts)
3541 {
3542 struct sockaddr_un sunaddr;
3543 const char *path;
3544 Channel *c;
3545 int port, sock;
3546 mode_t omask;
3547
3548 switch (type) {
3549 case SSH_CHANNEL_UNIX_LISTENER:
3550 if (fwd->connect_path != NULL) {
3551 if (strlen(fwd->connect_path) > sizeof(sunaddr.sun_path)) {
3552 error("Local connecting path too long: %s",
3553 fwd->connect_path);
3554 return 0;
3555 }
3556 path = fwd->connect_path;
3557 port = PORT_STREAMLOCAL;
3558 } else {
3559 if (fwd->connect_host == NULL) {
3560 error("No forward host name.");
3561 return 0;
3562 }
3563 if (strlen(fwd->connect_host) >= NI_MAXHOST) {
3564 error("Forward host name too long.");
3565 return 0;
3566 }
3567 path = fwd->connect_host;
3568 port = fwd->connect_port;
3569 }
3570 break;
3571 case SSH_CHANNEL_RUNIX_LISTENER:
3572 path = fwd->listen_path;
3573 port = PORT_STREAMLOCAL;
3574 break;
3575 default:
3576 error("%s: unexpected channel type %d", __func__, type);
3577 return 0;
3578 }
3579
3580 if (fwd->listen_path == NULL) {
3581 error("No forward path name.");
3582 return 0;
3583 }
3584 if (strlen(fwd->listen_path) > sizeof(sunaddr.sun_path)) {
3585 error("Local listening path too long: %s", fwd->listen_path);
3586 return 0;
3587 }
3588
3589 debug3("%s: type %d path %s", __func__, type, fwd->listen_path);
3590
3591 /* Start a Unix domain listener. */
3592 omask = umask(fwd_opts->streamlocal_bind_mask);
3593 sock = unix_listener(fwd->listen_path, SSH_LISTEN_BACKLOG,
3594 fwd_opts->streamlocal_bind_unlink);
3595 umask(omask);
3596 if (sock < 0)
3597 return 0;
3598
3599 debug("Local forwarding listening on path %s.", fwd->listen_path);
3600
3601 /* Allocate a channel number for the socket. */
3602 c = channel_new(ssh, "unix listener", type, sock, sock, -1,
3603 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
3604 0, "unix listener", 1);
3605 c->path = xstrdup(path);
3606 c->host_port = port;
3607 c->listening_port = PORT_STREAMLOCAL;
3608 c->listening_addr = xstrdup(fwd->listen_path);
3609 return 1;
3610 }
3611
3612 static int
3613 channel_cancel_rport_listener_tcpip(struct ssh *ssh,
3614 const char *host, u_short port)
3615 {
3616 u_int i;
3617 int found = 0;
3618
3619 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) {
3620 Channel *c = ssh->chanctxt->channels[i];
3621 if (c == NULL || c->type != SSH_CHANNEL_RPORT_LISTENER)
3622 continue;
3623 if (strcmp(c->path, host) == 0 && c->listening_port == port) {
3624 debug2("%s: close channel %d", __func__, i);
3625 channel_free(ssh, c);
3626 found = 1;
3627 }
3628 }
3629
3630 return found;
3631 }
3632
3633 static int
3634 channel_cancel_rport_listener_streamlocal(struct ssh *ssh, const char *path)
3635 {
3636 u_int i;
3637 int found = 0;
3638
3639 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) {
3640 Channel *c = ssh->chanctxt->channels[i];
3641 if (c == NULL || c->type != SSH_CHANNEL_RUNIX_LISTENER)
3642 continue;
3643 if (c->path == NULL)
3644 continue;
3645 if (strcmp(c->path, path) == 0) {
3646 debug2("%s: close channel %d", __func__, i);
3647 channel_free(ssh, c);
3648 found = 1;
3649 }
3650 }
3651
3652 return found;
3653 }
3654
3655 int
3656 channel_cancel_rport_listener(struct ssh *ssh, struct Forward *fwd)
3657 {
3658 if (fwd->listen_path != NULL) {
3659 return channel_cancel_rport_listener_streamlocal(ssh,
3660 fwd->listen_path);
3661 } else {
3662 return channel_cancel_rport_listener_tcpip(ssh,
3663 fwd->listen_host, fwd->listen_port);
3664 }
3665 }
3666
3667 static int
3668 channel_cancel_lport_listener_tcpip(struct ssh *ssh,
3669 const char *lhost, u_short lport, int cport,
3670 struct ForwardOptions *fwd_opts)
3671 {
3672 u_int i;
3673 int found = 0;
3674 const char *addr = channel_fwd_bind_addr(ssh, lhost, NULL, 1, fwd_opts);
3675
3676 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) {
3677 Channel *c = ssh->chanctxt->channels[i];
3678 if (c == NULL || c->type != SSH_CHANNEL_PORT_LISTENER)
3679 continue;
3680 if (c->listening_port != lport)
3681 continue;
3682 if (cport == CHANNEL_CANCEL_PORT_STATIC) {
3683 /* skip dynamic forwardings */
3684 if (c->host_port == 0)
3685 continue;
3686 } else {
3687 if (c->host_port != cport)
3688 continue;
3689 }
3690 if ((c->listening_addr == NULL && addr != NULL) ||
3691 (c->listening_addr != NULL && addr == NULL))
3692 continue;
3693 if (addr == NULL || strcmp(c->listening_addr, addr) == 0) {
3694 debug2("%s: close channel %d", __func__, i);
3695 channel_free(ssh, c);
3696 found = 1;
3697 }
3698 }
3699
3700 return found;
3701 }
3702
3703 static int
3704 channel_cancel_lport_listener_streamlocal(struct ssh *ssh, const char *path)
3705 {
3706 u_int i;
3707 int found = 0;
3708
3709 if (path == NULL) {
3710 error("%s: no path specified.", __func__);
3711 return 0;
3712 }
3713
3714 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) {
3715 Channel *c = ssh->chanctxt->channels[i];
3716 if (c == NULL || c->type != SSH_CHANNEL_UNIX_LISTENER)
3717 continue;
3718 if (c->listening_addr == NULL)
3719 continue;
3720 if (strcmp(c->listening_addr, path) == 0) {
3721 debug2("%s: close channel %d", __func__, i);
3722 channel_free(ssh, c);
3723 found = 1;
3724 }
3725 }
3726
3727 return found;
3728 }
3729
3730 int
3731 channel_cancel_lport_listener(struct ssh *ssh,
3732 struct Forward *fwd, int cport, struct ForwardOptions *fwd_opts)
3733 {
3734 if (fwd->listen_path != NULL) {
3735 return channel_cancel_lport_listener_streamlocal(ssh,
3736 fwd->listen_path);
3737 } else {
3738 return channel_cancel_lport_listener_tcpip(ssh,
3739 fwd->listen_host, fwd->listen_port, cport, fwd_opts);
3740 }
3741 }
3742
3743 /* protocol local port fwd, used by ssh */
3744 int
3745 channel_setup_local_fwd_listener(struct ssh *ssh,
3746 struct Forward *fwd, struct ForwardOptions *fwd_opts)
3747 {
3748 if (fwd->listen_path != NULL) {
3749 return channel_setup_fwd_listener_streamlocal(ssh,
3750 SSH_CHANNEL_UNIX_LISTENER, fwd, fwd_opts);
3751 } else {
3752 return channel_setup_fwd_listener_tcpip(ssh,
3753 SSH_CHANNEL_PORT_LISTENER, fwd, NULL, fwd_opts);
3754 }
3755 }
3756
3757 /* Matches a remote forwarding permission against a requested forwarding */
3758 static int
3759 remote_open_match(struct permission *allowed_open, struct Forward *fwd)
3760 {
3761 int ret;
3762 char *lhost;
3763
3764 /* XXX add ACLs for streamlocal */
3765 if (fwd->listen_path != NULL)
3766 return 1;
3767
3768 if (fwd->listen_host == NULL || allowed_open->listen_host == NULL)
3769 return 0;
3770
3771 if (allowed_open->listen_port != FWD_PERMIT_ANY_PORT &&
3772 allowed_open->listen_port != fwd->listen_port)
3773 return 0;
3774
3775 /* Match hostnames case-insensitively */
3776 lhost = xstrdup(fwd->listen_host);
3777 lowercase(lhost);
3778 ret = match_pattern(lhost, allowed_open->listen_host);
3779 free(lhost);
3780
3781 return ret;
3782 }
3783
3784 /* Checks whether a requested remote forwarding is permitted */
3785 static int
3786 check_rfwd_permission(struct ssh *ssh, struct Forward *fwd)
3787 {
3788 struct ssh_channels *sc = ssh->chanctxt;
3789 struct permission_set *pset = &sc->remote_perms;
3790 u_int i, permit, permit_adm = 1;
3791 struct permission *perm;
3792
3793 /* XXX apply GatewayPorts override before checking? */
3794
3795 permit = pset->all_permitted;
3796 if (!permit) {
3797 for (i = 0; i < pset->num_permitted_user; i++) {
3798 perm = &pset->permitted_user[i];
3799 if (remote_open_match(perm, fwd)) {
3800 permit = 1;
3801 break;
3802 }
3803 }
3804 }
3805
3806 if (pset->num_permitted_admin > 0) {
3807 permit_adm = 0;
3808 for (i = 0; i < pset->num_permitted_admin; i++) {
3809 perm = &pset->permitted_admin[i];
3810 if (remote_open_match(perm, fwd)) {
3811 permit_adm = 1;
3812 break;
3813 }
3814 }
3815 }
3816
3817 return permit && permit_adm;
3818 }
3819
3820 /* protocol v2 remote port fwd, used by sshd */
3821 int
3822 channel_setup_remote_fwd_listener(struct ssh *ssh, struct Forward *fwd,
3823 int *allocated_listen_port, struct ForwardOptions *fwd_opts)
3824 {
3825 if (!check_rfwd_permission(ssh, fwd)) {
3826 ssh_packet_send_debug(ssh, "port forwarding refused");
3827 if (fwd->listen_path != NULL)
3828 /* XXX always allowed, see remote_open_match() */
3829 logit("Received request from %.100s port %d to "
3830 "remote forward to path \"%.100s\", "
3831 "but the request was denied.",
3832 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh),
3833 fwd->listen_path);
3834 else if(fwd->listen_host != NULL)
3835 logit("Received request from %.100s port %d to "
3836 "remote forward to host %.100s port %d, "
3837 "but the request was denied.",
3838 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh),
3839 fwd->listen_host, fwd->listen_port );
3840 else
3841 logit("Received request from %.100s port %d to remote "
3842 "forward, but the request was denied.",
3843 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
3844 return 0;
3845 }
3846 if (fwd->listen_path != NULL) {
3847 return channel_setup_fwd_listener_streamlocal(ssh,
3848 SSH_CHANNEL_RUNIX_LISTENER, fwd, fwd_opts);
3849 } else {
3850 return channel_setup_fwd_listener_tcpip(ssh,
3851 SSH_CHANNEL_RPORT_LISTENER, fwd, allocated_listen_port,
3852 fwd_opts);
3853 }
3854 }
3855
3856 /*
3857 * Translate the requested rfwd listen host to something usable for
3858 * this server.
3859 */
3860 static const char *
3861 channel_rfwd_bind_host(const char *listen_host)
3862 {
3863 if (listen_host == NULL) {
3864 return "localhost";
3865 } else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0) {
3866 return "";
3867 } else
3868 return listen_host;
3869 }
3870
3871 /*
3872 * Initiate forwarding of connections to port "port" on remote host through
3873 * the secure channel to host:port from local side.
3874 * Returns handle (index) for updating the dynamic listen port with
3875 * channel_update_permission().
3876 */
3877 int
3878 channel_request_remote_forwarding(struct ssh *ssh, struct Forward *fwd)
3879 {
3880 int r, success = 0, idx = -1;
3881 char *host_to_connect, *listen_host, *listen_path;
3882 int port_to_connect, listen_port;
3883
3884 /* Send the forward request to the remote side. */
3885 if (fwd->listen_path != NULL) {
3886 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 ||
3887 (r = sshpkt_put_cstring(ssh,
3888 "streamlocal-forward@openssh.com")) != 0 ||
3889 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* want reply */
3890 (r = sshpkt_put_cstring(ssh, fwd->listen_path)) != 0 ||
3891 (r = sshpkt_send(ssh)) != 0 ||
3892 (r = ssh_packet_write_wait(ssh)) != 0)
3893 fatal("%s: request streamlocal: %s",
3894 __func__, ssh_err(r));
3895 } else {
3896 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 ||
3897 (r = sshpkt_put_cstring(ssh, "tcpip-forward")) != 0 ||
3898 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* want reply */
3899 (r = sshpkt_put_cstring(ssh,
3900 channel_rfwd_bind_host(fwd->listen_host))) != 0 ||
3901 (r = sshpkt_put_u32(ssh, fwd->listen_port)) != 0 ||
3902 (r = sshpkt_send(ssh)) != 0 ||
3903 (r = ssh_packet_write_wait(ssh)) != 0)
3904 fatal("%s: request tcpip-forward: %s",
3905 __func__, ssh_err(r));
3906 }
3907 /* Assume that server accepts the request */
3908 success = 1;
3909 if (success) {
3910 /* Record that connection to this host/port is permitted. */
3911 host_to_connect = listen_host = listen_path = NULL;
3912 port_to_connect = listen_port = 0;
3913 if (fwd->connect_path != NULL) {
3914 host_to_connect = xstrdup(fwd->connect_path);
3915 port_to_connect = PORT_STREAMLOCAL;
3916 } else {
3917 host_to_connect = xstrdup(fwd->connect_host);
3918 port_to_connect = fwd->connect_port;
3919 }
3920 if (fwd->listen_path != NULL) {
3921 listen_path = xstrdup(fwd->listen_path);
3922 listen_port = PORT_STREAMLOCAL;
3923 } else {
3924 if (fwd->listen_host != NULL)
3925 listen_host = xstrdup(fwd->listen_host);
3926 listen_port = fwd->listen_port;
3927 }
3928 idx = permission_set_add(ssh, FORWARD_USER, FORWARD_LOCAL,
3929 host_to_connect, port_to_connect,
3930 listen_host, listen_path, listen_port, NULL);
3931 }
3932 return idx;
3933 }
3934
3935 static int
3936 open_match(struct permission *allowed_open, const char *requestedhost,
3937 int requestedport)
3938 {
3939 if (allowed_open->host_to_connect == NULL)
3940 return 0;
3941 if (allowed_open->port_to_connect != FWD_PERMIT_ANY_PORT &&
3942 allowed_open->port_to_connect != requestedport)
3943 return 0;
3944 if (strcmp(allowed_open->host_to_connect, FWD_PERMIT_ANY_HOST) != 0 &&
3945 strcmp(allowed_open->host_to_connect, requestedhost) != 0)
3946 return 0;
3947 return 1;
3948 }
3949
3950 /*
3951 * Note that in the listen host/port case
3952 * we don't support FWD_PERMIT_ANY_PORT and
3953 * need to translate between the configured-host (listen_host)
3954 * and what we've sent to the remote server (channel_rfwd_bind_host)
3955 */
3956 static int
3957 open_listen_match_tcpip(struct permission *allowed_open,
3958 const char *requestedhost, u_short requestedport, int translate)
3959 {
3960 const char *allowed_host;
3961
3962 if (allowed_open->host_to_connect == NULL)
3963 return 0;
3964 if (allowed_open->listen_port != requestedport)
3965 return 0;
3966 if (!translate && allowed_open->listen_host == NULL &&
3967 requestedhost == NULL)
3968 return 1;
3969 allowed_host = translate ?
3970 channel_rfwd_bind_host(allowed_open->listen_host) :
3971 allowed_open->listen_host;
3972 if (allowed_host == NULL || requestedhost == NULL ||
3973 strcmp(allowed_host, requestedhost) != 0)
3974 return 0;
3975 return 1;
3976 }
3977
3978 static int
3979 open_listen_match_streamlocal(struct permission *allowed_open,
3980 const char *requestedpath)
3981 {
3982 if (allowed_open->host_to_connect == NULL)
3983 return 0;
3984 if (allowed_open->listen_port != PORT_STREAMLOCAL)
3985 return 0;
3986 if (allowed_open->listen_path == NULL ||
3987 strcmp(allowed_open->listen_path, requestedpath) != 0)
3988 return 0;
3989 return 1;
3990 }
3991
3992 /*
3993 * Request cancellation of remote forwarding of connection host:port from
3994 * local side.
3995 */
3996 static int
3997 channel_request_rforward_cancel_tcpip(struct ssh *ssh,
3998 const char *host, u_short port)
3999 {
4000 struct ssh_channels *sc = ssh->chanctxt;
4001 struct permission_set *pset = &sc->local_perms;
4002 int r;
4003 u_int i;
4004 struct permission *perm = NULL;
4005
4006 for (i = 0; i < pset->num_permitted_user; i++) {
4007 perm = &pset->permitted_user[i];
4008 if (open_listen_match_tcpip(perm, host, port, 0))
4009 break;
4010 perm = NULL;
4011 }
4012 if (perm == NULL) {
4013 debug("%s: requested forward not found", __func__);
4014 return -1;
4015 }
4016 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 ||
4017 (r = sshpkt_put_cstring(ssh, "cancel-tcpip-forward")) != 0 ||
4018 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* want reply */
4019 (r = sshpkt_put_cstring(ssh, channel_rfwd_bind_host(host))) != 0 ||
4020 (r = sshpkt_put_u32(ssh, port)) != 0 ||
4021 (r = sshpkt_send(ssh)) != 0)
4022 fatal("%s: send cancel: %s", __func__, ssh_err(r));
4023
4024 fwd_perm_clear(perm); /* unregister */
4025
4026 return 0;
4027 }
4028
4029 /*
4030 * Request cancellation of remote forwarding of Unix domain socket
4031 * path from local side.
4032 */
4033 static int
4034 channel_request_rforward_cancel_streamlocal(struct ssh *ssh, const char *path)
4035 {
4036 struct ssh_channels *sc = ssh->chanctxt;
4037 struct permission_set *pset = &sc->local_perms;
4038 int r;
4039 u_int i;
4040 struct permission *perm = NULL;
4041
4042 for (i = 0; i < pset->num_permitted_user; i++) {
4043 perm = &pset->permitted_user[i];
4044 if (open_listen_match_streamlocal(perm, path))
4045 break;
4046 perm = NULL;
4047 }
4048 if (perm == NULL) {
4049 debug("%s: requested forward not found", __func__);
4050 return -1;
4051 }
4052 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 ||
4053 (r = sshpkt_put_cstring(ssh,
4054 "cancel-streamlocal-forward@openssh.com")) != 0 ||
4055 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* want reply */
4056 (r = sshpkt_put_cstring(ssh, path)) != 0 ||
4057 (r = sshpkt_send(ssh)) != 0)
4058 fatal("%s: send cancel: %s", __func__, ssh_err(r));
4059
4060 fwd_perm_clear(perm); /* unregister */
4061
4062 return 0;
4063 }
4064
4065 /*
4066 * Request cancellation of remote forwarding of a connection from local side.
4067 */
4068 int
4069 channel_request_rforward_cancel(struct ssh *ssh, struct Forward *fwd)
4070 {
4071 if (fwd->listen_path != NULL) {
4072 return channel_request_rforward_cancel_streamlocal(ssh,
4073 fwd->listen_path);
4074 } else {
4075 return channel_request_rforward_cancel_tcpip(ssh,
4076 fwd->listen_host,
4077 fwd->listen_port ? fwd->listen_port : fwd->allocated_port);
4078 }
4079 }
4080
4081 /*
4082 * Permits opening to any host/port if permitted_user[] is empty. This is
4083 * usually called by the server, because the user could connect to any port
4084 * anyway, and the server has no way to know but to trust the client anyway.
4085 */
4086 void
4087 channel_permit_all(struct ssh *ssh, int where)
4088 {
4089 struct permission_set *pset = permission_set_get(ssh, where);
4090
4091 if (pset->num_permitted_user == 0)
4092 pset->all_permitted = 1;
4093 }
4094
4095 /*
4096 * Permit the specified host/port for forwarding.
4097 */
4098 void
4099 channel_add_permission(struct ssh *ssh, int who, int where,
4100 char *host, int port)
4101 {
4102 int local = where == FORWARD_LOCAL;
4103 struct permission_set *pset = permission_set_get(ssh, where);
4104
4105 debug("allow %s forwarding to host %s port %d",
4106 fwd_ident(who, where), host, port);
4107 /*
4108 * Remote forwards set listen_host/port, local forwards set
4109 * host/port_to_connect.
4110 */
4111 permission_set_add(ssh, who, where,
4112 local ? host : 0, local ? port : 0,
4113 local ? NULL : host, NULL, local ? 0 : port, NULL);
4114 pset->all_permitted = 0;
4115 }
4116
4117 /*
4118 * Administratively disable forwarding.
4119 */
4120 void
4121 channel_disable_admin(struct ssh *ssh, int where)
4122 {
4123 channel_clear_permission(ssh, FORWARD_ADM, where);
4124 permission_set_add(ssh, FORWARD_ADM, where,
4125 NULL, 0, NULL, NULL, 0, NULL);
4126 }
4127
4128 /*
4129 * Clear a list of permitted opens.
4130 */
4131 void
4132 channel_clear_permission(struct ssh *ssh, int who, int where)
4133 {
4134 struct permission **permp;
4135 u_int *npermp;
4136
4137 permission_set_get_array(ssh, who, where, &permp, &npermp);
4138 *permp = xrecallocarray(*permp, *npermp, 0, sizeof(**permp));
4139 *npermp = 0;
4140 }
4141
4142 /*
4143 * Update the listen port for a dynamic remote forward, after
4144 * the actual 'newport' has been allocated. If 'newport' < 0 is
4145 * passed then they entry will be invalidated.
4146 */
4147 void
4148 channel_update_permission(struct ssh *ssh, int idx, int newport)
4149 {
4150 struct permission_set *pset = &ssh->chanctxt->local_perms;
4151
4152 if (idx < 0 || (u_int)idx >= pset->num_permitted_user) {
4153 debug("%s: index out of range: %d num_permitted_user %d",
4154 __func__, idx, pset->num_permitted_user);
4155 return;
4156 }
4157 debug("%s allowed port %d for forwarding to host %s port %d",
4158 newport > 0 ? "Updating" : "Removing",
4159 newport,
4160 pset->permitted_user[idx].host_to_connect,
4161 pset->permitted_user[idx].port_to_connect);
4162 if (newport <= 0)
4163 fwd_perm_clear(&pset->permitted_user[idx]);
4164 else {
4165 pset->permitted_user[idx].listen_port =
4166 (datafellows & SSH_BUG_DYNAMIC_RPORT) ? 0 : newport;
4167 }
4168 }
4169
4170 /* returns port number, FWD_PERMIT_ANY_PORT or -1 on error */
4171 int
4172 permitopen_port(const char *p)
4173 {
4174 int port;
4175
4176 if (strcmp(p, "*") == 0)
4177 return FWD_PERMIT_ANY_PORT;
4178 if ((port = a2port(p)) > 0)
4179 return port;
4180 return -1;
4181 }
4182
4183 /* Try to start non-blocking connect to next host in cctx list */
4184 static int
4185 connect_next(struct channel_connect *cctx)
4186 {
4187 int sock, saved_errno;
4188 struct sockaddr_un *sunaddr;
4189 char ntop[NI_MAXHOST];
4190 char strport[MAXIMUM(NI_MAXSERV, sizeof(sunaddr->sun_path))];
4191
4192 for (; cctx->ai; cctx->ai = cctx->ai->ai_next) {
4193 switch (cctx->ai->ai_family) {
4194 case AF_UNIX:
4195 /* unix:pathname instead of host:port */
4196 sunaddr = (struct sockaddr_un *)cctx->ai->ai_addr;
4197 strlcpy(ntop, "unix", sizeof(ntop));
4198 strlcpy(strport, sunaddr->sun_path, sizeof(strport));
4199 break;
4200 case AF_INET:
4201 case AF_INET6:
4202 if (getnameinfo(cctx->ai->ai_addr, cctx->ai->ai_addrlen,
4203 ntop, sizeof(ntop), strport, sizeof(strport),
4204 NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
4205 error("connect_next: getnameinfo failed");
4206 continue;
4207 }
4208 break;
4209 default:
4210 continue;
4211 }
4212 if ((sock = socket(cctx->ai->ai_family, cctx->ai->ai_socktype,
4213 cctx->ai->ai_protocol)) == -1) {
4214 if (cctx->ai->ai_next == NULL)
4215 error("socket: %.100s", strerror(errno));
4216 else
4217 verbose("socket: %.100s", strerror(errno));
4218 continue;
4219 }
4220 if (set_nonblock(sock) == -1)
4221 fatal("%s: set_nonblock(%d)", __func__, sock);
4222 if (connect(sock, cctx->ai->ai_addr,
4223 cctx->ai->ai_addrlen) == -1 && errno != EINPROGRESS) {
4224 debug("connect_next: host %.100s ([%.100s]:%s): "
4225 "%.100s", cctx->host, ntop, strport,
4226 strerror(errno));
4227 saved_errno = errno;
4228 close(sock);
4229 errno = saved_errno;
4230 continue; /* fail -- try next */
4231 }
4232 if (cctx->ai->ai_family != AF_UNIX)
4233 set_nodelay(sock);
4234 debug("connect_next: host %.100s ([%.100s]:%s) "
4235 "in progress, fd=%d", cctx->host, ntop, strport, sock);
4236 cctx->ai = cctx->ai->ai_next;
4237 return sock;
4238 }
4239 return -1;
4240 }
4241
4242 static void
4243 channel_connect_ctx_free(struct channel_connect *cctx)
4244 {
4245 free(cctx->host);
4246 if (cctx->aitop) {
4247 if (cctx->aitop->ai_family == AF_UNIX)
4248 free(cctx->aitop);
4249 else
4250 freeaddrinfo(cctx->aitop);
4251 }
4252 memset(cctx, 0, sizeof(*cctx));
4253 }
4254
4255 /*
4256 * Return connecting socket to remote host:port or local socket path,
4257 * passing back the failure reason if appropriate.
4258 */
4259 static int
4260 connect_to_helper(struct ssh *ssh, const char *name, int port, int socktype,
4261 char *ctype, char *rname, struct channel_connect *cctx,
4262 int *reason, const char **errmsg)
4263 {
4264 struct addrinfo hints;
4265 int gaierr;
4266 int sock = -1;
4267 char strport[NI_MAXSERV];
4268
4269 if (port == PORT_STREAMLOCAL) {
4270 struct sockaddr_un *sunaddr;
4271 struct addrinfo *ai;
4272
4273 if (strlen(name) > sizeof(sunaddr->sun_path)) {
4274 error("%.100s: %.100s", name, strerror(ENAMETOOLONG));
4275 return -1;
4276 }
4277
4278 /*
4279 * Fake up a struct addrinfo for AF_UNIX connections.
4280 * channel_connect_ctx_free() must check ai_family
4281 * and use free() not freeaddirinfo() for AF_UNIX.
4282 */
4283 ai = xmalloc(sizeof(*ai) + sizeof(*sunaddr));
4284 memset(ai, 0, sizeof(*ai) + sizeof(*sunaddr));
4285 ai->ai_addr = (struct sockaddr *)(ai + 1);
4286 ai->ai_addrlen = sizeof(*sunaddr);
4287 ai->ai_family = AF_UNIX;
4288 ai->ai_socktype = socktype;
4289 ai->ai_protocol = PF_UNSPEC;
4290 sunaddr = (struct sockaddr_un *)ai->ai_addr;
4291 sunaddr->sun_family = AF_UNIX;
4292 strlcpy(sunaddr->sun_path, name, sizeof(sunaddr->sun_path));
4293 cctx->aitop = ai;
4294 } else {
4295 memset(&hints, 0, sizeof(hints));
4296 hints.ai_family = ssh->chanctxt->IPv4or6;
4297 hints.ai_socktype = socktype;
4298 snprintf(strport, sizeof strport, "%d", port);
4299 if ((gaierr = getaddrinfo(name, strport, &hints, &cctx->aitop))
4300 != 0) {
4301 if (errmsg != NULL)
4302 *errmsg = ssh_gai_strerror(gaierr);
4303 if (reason != NULL)
4304 *reason = SSH2_OPEN_CONNECT_FAILED;
4305 error("connect_to %.100s: unknown host (%s)", name,
4306 ssh_gai_strerror(gaierr));
4307 return -1;
4308 }
4309 }
4310
4311 cctx->host = xstrdup(name);
4312 cctx->port = port;
4313 cctx->ai = cctx->aitop;
4314
4315 if ((sock = connect_next(cctx)) == -1) {
4316 error("connect to %.100s port %d failed: %s",
4317 name, port, strerror(errno));
4318 return -1;
4319 }
4320
4321 return sock;
4322 }
4323
4324 /* Return CONNECTING channel to remote host:port or local socket path */
4325 static Channel *
4326 connect_to(struct ssh *ssh, const char *host, int port,
4327 char *ctype, char *rname)
4328 {
4329 struct channel_connect cctx;
4330 Channel *c;
4331 int sock;
4332
4333 memset(&cctx, 0, sizeof(cctx));
4334 sock = connect_to_helper(ssh, host, port, SOCK_STREAM, ctype, rname,
4335 &cctx, NULL, NULL);
4336 if (sock == -1) {
4337 channel_connect_ctx_free(&cctx);
4338 return NULL;
4339 }
4340 c = channel_new(ssh, ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1,
4341 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1);
4342 c->host_port = port;
4343 c->path = xstrdup(host);
4344 c->connect_ctx = cctx;
4345
4346 return c;
4347 }
4348
4349 /*
4350 * returns either the newly connected channel or the downstream channel
4351 * that needs to deal with this connection.
4352 */
4353 Channel *
4354 channel_connect_by_listen_address(struct ssh *ssh, const char *listen_host,
4355 u_short listen_port, char *ctype, char *rname)
4356 {
4357 struct ssh_channels *sc = ssh->chanctxt;
4358 struct permission_set *pset = &sc->local_perms;
4359 u_int i;
4360 struct permission *perm;
4361
4362 for (i = 0; i < pset->num_permitted_user; i++) {
4363 perm = &pset->permitted_user[i];
4364 if (open_listen_match_tcpip(perm,
4365 listen_host, listen_port, 1)) {
4366 if (perm->downstream)
4367 return perm->downstream;
4368 if (perm->port_to_connect == 0)
4369 return rdynamic_connect_prepare(ssh,
4370 ctype, rname);
4371 return connect_to(ssh,
4372 perm->host_to_connect, perm->port_to_connect,
4373 ctype, rname);
4374 }
4375 }
4376 error("WARNING: Server requests forwarding for unknown listen_port %d",
4377 listen_port);
4378 return NULL;
4379 }
4380
4381 Channel *
4382 channel_connect_by_listen_path(struct ssh *ssh, const char *path,
4383 char *ctype, char *rname)
4384 {
4385 struct ssh_channels *sc = ssh->chanctxt;
4386 struct permission_set *pset = &sc->local_perms;
4387 u_int i;
4388 struct permission *perm;
4389
4390 for (i = 0; i < pset->num_permitted_user; i++) {
4391 perm = &pset->permitted_user[i];
4392 if (open_listen_match_streamlocal(perm, path)) {
4393 return connect_to(ssh,
4394 perm->host_to_connect, perm->port_to_connect,
4395 ctype, rname);
4396 }
4397 }
4398 error("WARNING: Server requests forwarding for unknown path %.100s",
4399 path);
4400 return NULL;
4401 }
4402
4403 /* Check if connecting to that port is permitted and connect. */
4404 Channel *
4405 channel_connect_to_port(struct ssh *ssh, const char *host, u_short port,
4406 char *ctype, char *rname, int *reason, const char **errmsg)
4407 {
4408 struct ssh_channels *sc = ssh->chanctxt;
4409 struct permission_set *pset = &sc->local_perms;
4410 struct channel_connect cctx;
4411 Channel *c;
4412 u_int i, permit, permit_adm = 1;
4413 int sock;
4414 struct permission *perm;
4415
4416 permit = pset->all_permitted;
4417 if (!permit) {
4418 for (i = 0; i < pset->num_permitted_user; i++) {
4419 perm = &pset->permitted_user[i];
4420 if (open_match(perm, host, port)) {
4421 permit = 1;
4422 break;
4423 }
4424 }
4425 }
4426
4427 if (pset->num_permitted_admin > 0) {
4428 permit_adm = 0;
4429 for (i = 0; i < pset->num_permitted_admin; i++) {
4430 perm = &pset->permitted_admin[i];
4431 if (open_match(perm, host, port)) {
4432 permit_adm = 1;
4433 break;
4434 }
4435 }
4436 }
4437
4438 if (!permit || !permit_adm) {
4439 logit("Received request from %.100s port %d to connect to "
4440 "host %.100s port %d, but the request was denied.",
4441 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), host, port);
4442 if (reason != NULL)
4443 *reason = SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED;
4444 return NULL;
4445 }
4446
4447 memset(&cctx, 0, sizeof(cctx));
4448 sock = connect_to_helper(ssh, host, port, SOCK_STREAM, ctype, rname,
4449 &cctx, reason, errmsg);
4450 if (sock == -1) {
4451 channel_connect_ctx_free(&cctx);
4452 return NULL;
4453 }
4454
4455 c = channel_new(ssh, ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1,
4456 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1);
4457 c->host_port = port;
4458 c->path = xstrdup(host);
4459 c->connect_ctx = cctx;
4460
4461 return c;
4462 }
4463
4464 /* Check if connecting to that path is permitted and connect. */
4465 Channel *
4466 channel_connect_to_path(struct ssh *ssh, const char *path,
4467 char *ctype, char *rname)
4468 {
4469 struct ssh_channels *sc = ssh->chanctxt;
4470 struct permission_set *pset = &sc->local_perms;
4471 u_int i, permit, permit_adm = 1;
4472 struct permission *perm;
4473
4474 permit = pset->all_permitted;
4475 if (!permit) {
4476 for (i = 0; i < pset->num_permitted_user; i++) {
4477 perm = &pset->permitted_user[i];
4478 if (open_match(perm, path, PORT_STREAMLOCAL)) {
4479 permit = 1;
4480 break;
4481 }
4482 }
4483 }
4484
4485 if (pset->num_permitted_admin > 0) {
4486 permit_adm = 0;
4487 for (i = 0; i < pset->num_permitted_admin; i++) {
4488 perm = &pset->permitted_admin[i];
4489 if (open_match(perm, path, PORT_STREAMLOCAL)) {
4490 permit_adm = 1;
4491 break;
4492 }
4493 }
4494 }
4495
4496 if (!permit || !permit_adm) {
4497 logit("Received request to connect to path %.100s, "
4498 "but the request was denied.", path);
4499 return NULL;
4500 }
4501 return connect_to(ssh, path, PORT_STREAMLOCAL, ctype, rname);
4502 }
4503
4504 void
4505 channel_send_window_changes(struct ssh *ssh)
4506 {
4507 struct ssh_channels *sc = ssh->chanctxt;
4508 struct winsize ws;
4509 int r;
4510 u_int i;
4511
4512 for (i = 0; i < sc->channels_alloc; i++) {
4513 if (sc->channels[i] == NULL || !sc->channels[i]->client_tty ||
4514 sc->channels[i]->type != SSH_CHANNEL_OPEN)
4515 continue;
4516 if (ioctl(sc->channels[i]->rfd, TIOCGWINSZ, &ws) == -1)
4517 continue;
4518 channel_request_start(ssh, i, "window-change", 0);
4519 if ((r = sshpkt_put_u32(ssh, (u_int)ws.ws_col)) != 0 ||
4520 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_row)) != 0 ||
4521 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_xpixel)) != 0 ||
4522 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_ypixel)) != 0 ||
4523 (r = sshpkt_send(ssh)) != 0)
4524 fatal("%s: channel %u: send window-change: %s",
4525 __func__, i, ssh_err(r));
4526 }
4527 }
4528
4529 /* Return RDYNAMIC_OPEN channel: channel allows SOCKS, but is not connected */
4530 static Channel *
4531 rdynamic_connect_prepare(struct ssh *ssh, char *ctype, char *rname)
4532 {
4533 Channel *c;
4534 int r;
4535
4536 c = channel_new(ssh, ctype, SSH_CHANNEL_RDYNAMIC_OPEN, -1, -1, -1,
4537 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1);
4538 c->host_port = 0;
4539 c->path = NULL;
4540
4541 /*
4542 * We need to open the channel before we have a FD,
4543 * so that we can get SOCKS header from peer.
4544 */
4545 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 ||
4546 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 ||
4547 (r = sshpkt_put_u32(ssh, c->self)) != 0 ||
4548 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 ||
4549 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0) {
4550 fatal("%s: channel %i: confirm: %s", __func__,
4551 c->self, ssh_err(r));
4552 }
4553 return c;
4554 }
4555
4556 /* Return CONNECTING socket to remote host:port or local socket path */
4557 static int
4558 rdynamic_connect_finish(struct ssh *ssh, Channel *c)
4559 {
4560 struct channel_connect cctx;
4561 int sock;
4562
4563 memset(&cctx, 0, sizeof(cctx));
4564 sock = connect_to_helper(ssh, c->path, c->host_port, SOCK_STREAM, NULL,
4565 NULL, &cctx, NULL, NULL);
4566 if (sock == -1)
4567 channel_connect_ctx_free(&cctx);
4568 else {
4569 /* similar to SSH_CHANNEL_CONNECTING but we've already sent the open */
4570 c->type = SSH_CHANNEL_RDYNAMIC_FINISH;
4571 c->connect_ctx = cctx;
4572 channel_register_fds(ssh, c, sock, sock, -1, 0, 1, 0);
4573 }
4574 return sock;
4575 }
4576
4577 /* -- X11 forwarding */
4578
4579 /*
4580 * Creates an internet domain socket for listening for X11 connections.
4581 * Returns 0 and a suitable display number for the DISPLAY variable
4582 * stored in display_numberp , or -1 if an error occurs.
4583 */
4584 int
4585 x11_create_display_inet(struct ssh *ssh, int x11_display_offset,
4586 int x11_use_localhost, int single_connection,
4587 u_int *display_numberp, int **chanids)
4588 {
4589 Channel *nc = NULL;
4590 int display_number, sock;
4591 u_short port;
4592 struct addrinfo hints, *ai, *aitop;
4593 char strport[NI_MAXSERV];
4594 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
4595
4596 if (chanids == NULL)
4597 return -1;
4598
4599 for (display_number = x11_display_offset;
4600 display_number < MAX_DISPLAYS;
4601 display_number++) {
4602 port = 6000 + display_number;
4603 memset(&hints, 0, sizeof(hints));
4604 hints.ai_family = ssh->chanctxt->IPv4or6;
4605 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE;
4606 hints.ai_socktype = SOCK_STREAM;
4607 snprintf(strport, sizeof strport, "%d", port);
4608 if ((gaierr = getaddrinfo(NULL, strport,
4609 &hints, &aitop)) != 0) {
4610 error("getaddrinfo: %.100s", ssh_gai_strerror(gaierr));
4611 return -1;
4612 }
4613 for (ai = aitop; ai; ai = ai->ai_next) {
4614 if (ai->ai_family != AF_INET &&
4615 ai->ai_family != AF_INET6)
4616 continue;
4617 sock = socket(ai->ai_family, ai->ai_socktype,
4618 ai->ai_protocol);
4619 if (sock == -1) {
4620 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)
4621 #ifdef EPFNOSUPPORT
4622 && (errno != EPFNOSUPPORT)
4623 #endif
4624 ) {
4625 error("socket: %.100s", strerror(errno));
4626 freeaddrinfo(aitop);
4627 return -1;
4628 } else {
4629 debug("x11_create_display_inet: Socket family %d not supported",
4630 ai->ai_family);
4631 continue;
4632 }
4633 }
4634 if (ai->ai_family == AF_INET6)
4635 sock_set_v6only(sock);
4636 if (x11_use_localhost)
4637 set_reuseaddr(sock);
4638 if (bind(sock, ai->ai_addr, ai->ai_addrlen) == -1) {
4639 debug2("%s: bind port %d: %.100s", __func__,
4640 port, strerror(errno));
4641 close(sock);
4642 for (n = 0; n < num_socks; n++)
4643 close(socks[n]);
4644 num_socks = 0;
4645 break;
4646 }
4647 socks[num_socks++] = sock;
4648 if (num_socks == NUM_SOCKS)
4649 break;
4650 }
4651 freeaddrinfo(aitop);
4652 if (num_socks > 0)
4653 break;
4654 }
4655 if (display_number >= MAX_DISPLAYS) {
4656 error("Failed to allocate internet-domain X11 display socket.");
4657 return -1;
4658 }
4659 /* Start listening for connections on the socket. */
4660 for (n = 0; n < num_socks; n++) {
4661 sock = socks[n];
4662 if (listen(sock, SSH_LISTEN_BACKLOG) == -1) {
4663 error("listen: %.100s", strerror(errno));
4664 close(sock);
4665 return -1;
4666 }
4667 }
4668
4669 /* Allocate a channel for each socket. */
4670 *chanids = xcalloc(num_socks + 1, sizeof(**chanids));
4671 for (n = 0; n < num_socks; n++) {
4672 sock = socks[n];
4673 nc = channel_new(ssh, "x11 listener",
4674 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
4675 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
4676 0, "X11 inet listener", 1);
4677 nc->single_connection = single_connection;
4678 (*chanids)[n] = nc->self;
4679 }
4680 (*chanids)[n] = -1;
4681
4682 /* Return the display number for the DISPLAY environment variable. */
4683 *display_numberp = display_number;
4684 return 0;
4685 }
4686
4687 static int
4688 connect_local_xsocket_path(const char *pathname)
4689 {
4690 int sock;
4691 struct sockaddr_un addr;
4692
4693 sock = socket(AF_UNIX, SOCK_STREAM, 0);
4694 if (sock == -1)
4695 error("socket: %.100s", strerror(errno));
4696 memset(&addr, 0, sizeof(addr));
4697 addr.sun_family = AF_UNIX;
4698 strlcpy(addr.sun_path, pathname, sizeof addr.sun_path);
4699 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0)
4700 return sock;
4701 close(sock);
4702 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
4703 return -1;
4704 }
4705
4706 static int
4707 connect_local_xsocket(u_int dnr)
4708 {
4709 char buf[1024];
4710 snprintf(buf, sizeof buf, _PATH_UNIX_X, dnr);
4711 return connect_local_xsocket_path(buf);
4712 }
4713
4714 #ifdef __APPLE__
4715 static int
4716 is_path_to_xsocket(const char *display, char *path, size_t pathlen)
4717 {
4718 struct stat sbuf;
4719
4720 if (strlcpy(path, display, pathlen) >= pathlen) {
4721 error("%s: display path too long", __func__);
4722 return 0;
4723 }
4724 if (display[0] != '/')
4725 return 0;
4726 if (stat(path, &sbuf) == 0) {
4727 return 1;
4728 } else {
4729 char *dot = strrchr(path, '.');
4730 if (dot != NULL) {
4731 *dot = '\0';
4732 if (stat(path, &sbuf) == 0) {
4733 return 1;
4734 }
4735 }
4736 }
4737 return 0;
4738 }
4739 #endif
4740
4741 int
4742 x11_connect_display(struct ssh *ssh)
4743 {
4744 u_int display_number;
4745 const char *display;
4746 char buf[1024], *cp;
4747 struct addrinfo hints, *ai, *aitop;
4748 char strport[NI_MAXSERV];
4749 int gaierr, sock = 0;
4750
4751 /* Try to open a socket for the local X server. */
4752 display = getenv("DISPLAY");
4753 if (!display) {
4754 error("DISPLAY not set.");
4755 return -1;
4756 }
4757 /*
4758 * Now we decode the value of the DISPLAY variable and make a
4759 * connection to the real X server.
4760 */
4761
4762 #ifdef __APPLE__
4763 /* Check if display is a path to a socket (as set by launchd). */
4764 {
4765 char path[PATH_MAX];
4766
4767 if (is_path_to_xsocket(display, path, sizeof(path))) {
4768 debug("x11_connect_display: $DISPLAY is launchd");
4769
4770 /* Create a socket. */
4771 sock = connect_local_xsocket_path(path);
4772 if (sock < 0)
4773 return -1;
4774
4775 /* OK, we now have a connection to the display. */
4776 return sock;
4777 }
4778 }
4779 #endif
4780 /*
4781 * Check if it is a unix domain socket. Unix domain displays are in
4782 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
4783 */
4784 if (strncmp(display, "unix:", 5) == 0 ||
4785 display[0] == ':') {
4786 /* Connect to the unix domain socket. */
4787 if (sscanf(strrchr(display, ':') + 1, "%u",
4788 &display_number) != 1) {
4789 error("Could not parse display number from DISPLAY: "
4790 "%.100s", display);
4791 return -1;
4792 }
4793 /* Create a socket. */
4794 sock = connect_local_xsocket(display_number);
4795 if (sock < 0)
4796 return -1;
4797
4798 /* OK, we now have a connection to the display. */
4799 return sock;
4800 }
4801 /*
4802 * Connect to an inet socket. The DISPLAY value is supposedly
4803 * hostname:d[.s], where hostname may also be numeric IP address.
4804 */
4805 strlcpy(buf, display, sizeof(buf));
4806 cp = strchr(buf, ':');
4807 if (!cp) {
4808 error("Could not find ':' in DISPLAY: %.100s", display);
4809 return -1;
4810 }
4811 *cp = 0;
4812 /*
4813 * buf now contains the host name. But first we parse the
4814 * display number.
4815 */
4816 if (sscanf(cp + 1, "%u", &display_number) != 1) {
4817 error("Could not parse display number from DISPLAY: %.100s",
4818 display);
4819 return -1;
4820 }
4821
4822 /* Look up the host address */
4823 memset(&hints, 0, sizeof(hints));
4824 hints.ai_family = ssh->chanctxt->IPv4or6;
4825 hints.ai_socktype = SOCK_STREAM;
4826 snprintf(strport, sizeof strport, "%u", 6000 + display_number);
4827 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
4828 error("%.100s: unknown host. (%s)", buf,
4829 ssh_gai_strerror(gaierr));
4830 return -1;
4831 }
4832 for (ai = aitop; ai; ai = ai->ai_next) {
4833 /* Create a socket. */
4834 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
4835 if (sock == -1) {
4836 debug2("socket: %.100s", strerror(errno));
4837 continue;
4838 }
4839 /* Connect it to the display. */
4840 if (connect(sock, ai->ai_addr, ai->ai_addrlen) == -1) {
4841 debug2("connect %.100s port %u: %.100s", buf,
4842 6000 + display_number, strerror(errno));
4843 close(sock);
4844 continue;
4845 }
4846 /* Success */
4847 break;
4848 }
4849 freeaddrinfo(aitop);
4850 if (!ai) {
4851 error("connect %.100s port %u: %.100s", buf,
4852 6000 + display_number, strerror(errno));
4853 return -1;
4854 }
4855 set_nodelay(sock);
4856 return sock;
4857 }
4858
4859 /*
4860 * Requests forwarding of X11 connections, generates fake authentication
4861 * data, and enables authentication spoofing.
4862 * This should be called in the client only.
4863 */
4864 void
4865 x11_request_forwarding_with_spoofing(struct ssh *ssh, int client_session_id,
4866 const char *disp, const char *proto, const char *data, int want_reply)
4867 {
4868 struct ssh_channels *sc = ssh->chanctxt;
4869 u_int data_len = (u_int) strlen(data) / 2;
4870 u_int i, value;
4871 const char *cp;
4872 char *new_data;
4873 int r, screen_number;
4874
4875 if (sc->x11_saved_display == NULL)
4876 sc->x11_saved_display = xstrdup(disp);
4877 else if (strcmp(disp, sc->x11_saved_display) != 0) {
4878 error("x11_request_forwarding_with_spoofing: different "
4879 "$DISPLAY already forwarded");
4880 return;
4881 }
4882
4883 cp = strchr(disp, ':');
4884 if (cp)
4885 cp = strchr(cp, '.');
4886 if (cp)
4887 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL);
4888 else
4889 screen_number = 0;
4890
4891 if (sc->x11_saved_proto == NULL) {
4892 /* Save protocol name. */
4893 sc->x11_saved_proto = xstrdup(proto);
4894
4895 /* Extract real authentication data. */
4896 sc->x11_saved_data = xmalloc(data_len);
4897 for (i = 0; i < data_len; i++) {
4898 if (sscanf(data + 2 * i, "%2x", &value) != 1)
4899 fatal("x11_request_forwarding: bad "
4900 "authentication data: %.100s", data);
4901 sc->x11_saved_data[i] = value;
4902 }
4903 sc->x11_saved_data_len = data_len;
4904
4905 /* Generate fake data of the same length. */
4906 sc->x11_fake_data = xmalloc(data_len);
4907 arc4random_buf(sc->x11_fake_data, data_len);
4908 sc->x11_fake_data_len = data_len;
4909 }
4910
4911 /* Convert the fake data into hex. */
4912 new_data = tohex(sc->x11_fake_data, data_len);
4913
4914 /* Send the request packet. */
4915 channel_request_start(ssh, client_session_id, "x11-req", want_reply);
4916 if ((r = sshpkt_put_u8(ssh, 0)) != 0 || /* bool: single connection */
4917 (r = sshpkt_put_cstring(ssh, proto)) != 0 ||
4918 (r = sshpkt_put_cstring(ssh, new_data)) != 0 ||
4919 (r = sshpkt_put_u32(ssh, screen_number)) != 0 ||
4920 (r = sshpkt_send(ssh)) != 0 ||
4921 (r = ssh_packet_write_wait(ssh)) != 0)
4922 fatal("%s: send x11-req: %s", __func__, ssh_err(r));
4923 free(new_data);
4924 }
4925