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1 | /* | |
2 | * Author: Tatu Ylonen <ylo@cs.hut.fi> | |
3 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland | |
4 | * All rights reserved | |
5 | * This file contains functions for generic socket connection forwarding. | |
6 | * There is also code for initiating connection forwarding for X11 connections, | |
7 | * arbitrary tcp/ip connections, and the authentication agent connection. | |
8 | * | |
9 | * As far as I am concerned, the code I have written for this software | |
10 | * can be used freely for any purpose. Any derived versions of this | |
11 | * software must be clearly marked as such, and if the derived work is | |
12 | * incompatible with the protocol description in the RFC file, it must be | |
13 | * called by a name other than "ssh" or "Secure Shell". | |
14 | * | |
15 | * SSH2 support added by Markus Friedl. | |
16 | * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved. | |
17 | * Copyright (c) 1999 Dug Song. All rights reserved. | |
18 | * Copyright (c) 1999 Theo de Raadt. All rights reserved. | |
19 | * | |
20 | * Redistribution and use in source and binary forms, with or without | |
21 | * modification, are permitted provided that the following conditions | |
22 | * are met: | |
23 | * 1. Redistributions of source code must retain the above copyright | |
24 | * notice, this list of conditions and the following disclaimer. | |
25 | * 2. Redistributions in binary form must reproduce the above copyright | |
26 | * notice, this list of conditions and the following disclaimer in the | |
27 | * documentation and/or other materials provided with the distribution. | |
28 | * | |
29 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR | |
30 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES | |
31 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. | |
32 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, | |
33 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | |
34 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
35 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
36 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
37 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF | |
38 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
39 | */ | |
40 | ||
41 | #include "includes.h" | |
42 | RCSID("$OpenBSD: channels.c,v 1.206 2004/06/18 11:11:54 djm Exp $"); | |
43 | ||
44 | #include "ssh.h" | |
45 | #include "ssh1.h" | |
46 | #include "ssh2.h" | |
47 | #include "packet.h" | |
48 | #include "xmalloc.h" | |
49 | #include "log.h" | |
50 | #include "misc.h" | |
51 | #include "channels.h" | |
52 | #include "compat.h" | |
53 | #include "canohost.h" | |
54 | #include "key.h" | |
55 | #include "authfd.h" | |
56 | #include "pathnames.h" | |
57 | #include "bufaux.h" | |
58 | ||
59 | /* -- channel core */ | |
60 | ||
61 | /* | |
62 | * Pointer to an array containing all allocated channels. The array is | |
63 | * dynamically extended as needed. | |
64 | */ | |
65 | static Channel **channels = NULL; | |
66 | ||
67 | /* | |
68 | * Size of the channel array. All slots of the array must always be | |
69 | * initialized (at least the type field); unused slots set to NULL | |
70 | */ | |
71 | static int channels_alloc = 0; | |
72 | ||
73 | /* | |
74 | * Maximum file descriptor value used in any of the channels. This is | |
75 | * updated in channel_new. | |
76 | */ | |
77 | static int channel_max_fd = 0; | |
78 | ||
79 | ||
80 | /* -- tcp forwarding */ | |
81 | ||
82 | /* | |
83 | * Data structure for storing which hosts are permitted for forward requests. | |
84 | * The local sides of any remote forwards are stored in this array to prevent | |
85 | * a corrupt remote server from accessing arbitrary TCP/IP ports on our local | |
86 | * network (which might be behind a firewall). | |
87 | */ | |
88 | typedef struct { | |
89 | char *host_to_connect; /* Connect to 'host'. */ | |
90 | u_short port_to_connect; /* Connect to 'port'. */ | |
91 | u_short listen_port; /* Remote side should listen port number. */ | |
92 | } ForwardPermission; | |
93 | ||
94 | /* List of all permitted host/port pairs to connect. */ | |
95 | static ForwardPermission permitted_opens[SSH_MAX_FORWARDS_PER_DIRECTION]; | |
96 | ||
97 | /* Number of permitted host/port pairs in the array. */ | |
98 | static int num_permitted_opens = 0; | |
99 | /* | |
100 | * If this is true, all opens are permitted. This is the case on the server | |
101 | * on which we have to trust the client anyway, and the user could do | |
102 | * anything after logging in anyway. | |
103 | */ | |
104 | static int all_opens_permitted = 0; | |
105 | ||
106 | ||
107 | /* -- X11 forwarding */ | |
108 | ||
109 | /* Maximum number of fake X11 displays to try. */ | |
110 | #define MAX_DISPLAYS 1000 | |
111 | ||
112 | /* Saved X11 authentication protocol name. */ | |
113 | static char *x11_saved_proto = NULL; | |
114 | ||
115 | /* Saved X11 authentication data. This is the real data. */ | |
116 | static char *x11_saved_data = NULL; | |
117 | static u_int x11_saved_data_len = 0; | |
118 | ||
119 | /* | |
120 | * Fake X11 authentication data. This is what the server will be sending us; | |
121 | * we should replace any occurrences of this by the real data. | |
122 | */ | |
123 | static char *x11_fake_data = NULL; | |
124 | static u_int x11_fake_data_len; | |
125 | ||
126 | ||
127 | /* -- agent forwarding */ | |
128 | ||
129 | #define NUM_SOCKS 10 | |
130 | ||
131 | /* AF_UNSPEC or AF_INET or AF_INET6 */ | |
132 | static int IPv4or6 = AF_UNSPEC; | |
133 | ||
134 | /* helper */ | |
135 | static void port_open_helper(Channel *c, char *rtype); | |
136 | ||
137 | /* -- channel core */ | |
138 | ||
139 | Channel * | |
140 | channel_lookup(int id) | |
141 | { | |
142 | Channel *c; | |
143 | ||
144 | if (id < 0 || id >= channels_alloc) { | |
145 | logit("channel_lookup: %d: bad id", id); | |
146 | return NULL; | |
147 | } | |
148 | c = channels[id]; | |
149 | if (c == NULL) { | |
150 | logit("channel_lookup: %d: bad id: channel free", id); | |
151 | return NULL; | |
152 | } | |
153 | return c; | |
154 | } | |
155 | ||
156 | /* | |
157 | * Register filedescriptors for a channel, used when allocating a channel or | |
158 | * when the channel consumer/producer is ready, e.g. shell exec'd | |
159 | */ | |
160 | ||
161 | static void | |
162 | channel_register_fds(Channel *c, int rfd, int wfd, int efd, | |
163 | int extusage, int nonblock) | |
164 | { | |
165 | /* Update the maximum file descriptor value. */ | |
166 | channel_max_fd = MAX(channel_max_fd, rfd); | |
167 | channel_max_fd = MAX(channel_max_fd, wfd); | |
168 | channel_max_fd = MAX(channel_max_fd, efd); | |
169 | ||
170 | /* XXX set close-on-exec -markus */ | |
171 | ||
172 | c->rfd = rfd; | |
173 | c->wfd = wfd; | |
174 | c->sock = (rfd == wfd) ? rfd : -1; | |
175 | c->ctl_fd = -1; /* XXX: set elsewhere */ | |
176 | c->efd = efd; | |
177 | c->extended_usage = extusage; | |
178 | ||
179 | /* XXX ugly hack: nonblock is only set by the server */ | |
180 | if (nonblock && isatty(c->rfd)) { | |
181 | debug2("channel %d: rfd %d isatty", c->self, c->rfd); | |
182 | c->isatty = 1; | |
183 | if (!isatty(c->wfd)) { | |
184 | error("channel %d: wfd %d is not a tty?", | |
185 | c->self, c->wfd); | |
186 | } | |
187 | } else { | |
188 | c->isatty = 0; | |
189 | } | |
190 | c->wfd_isatty = isatty(c->wfd); | |
191 | ||
192 | /* enable nonblocking mode */ | |
193 | if (nonblock) { | |
194 | if (rfd != -1) | |
195 | set_nonblock(rfd); | |
196 | if (wfd != -1) | |
197 | set_nonblock(wfd); | |
198 | if (efd != -1) | |
199 | set_nonblock(efd); | |
200 | } | |
201 | } | |
202 | ||
203 | /* | |
204 | * Allocate a new channel object and set its type and socket. This will cause | |
205 | * remote_name to be freed. | |
206 | */ | |
207 | ||
208 | Channel * | |
209 | channel_new(char *ctype, int type, int rfd, int wfd, int efd, | |
210 | u_int window, u_int maxpack, int extusage, char *remote_name, int nonblock) | |
211 | { | |
212 | int i, found; | |
213 | Channel *c; | |
214 | ||
215 | /* Do initial allocation if this is the first call. */ | |
216 | if (channels_alloc == 0) { | |
217 | channels_alloc = 10; | |
218 | channels = xmalloc(channels_alloc * sizeof(Channel *)); | |
219 | for (i = 0; i < channels_alloc; i++) | |
220 | channels[i] = NULL; | |
221 | } | |
222 | /* Try to find a free slot where to put the new channel. */ | |
223 | for (found = -1, i = 0; i < channels_alloc; i++) | |
224 | if (channels[i] == NULL) { | |
225 | /* Found a free slot. */ | |
226 | found = i; | |
227 | break; | |
228 | } | |
229 | if (found == -1) { | |
230 | /* There are no free slots. Take last+1 slot and expand the array. */ | |
231 | found = channels_alloc; | |
232 | if (channels_alloc > 10000) | |
233 | fatal("channel_new: internal error: channels_alloc %d " | |
234 | "too big.", channels_alloc); | |
235 | channels = xrealloc(channels, | |
236 | (channels_alloc + 10) * sizeof(Channel *)); | |
237 | channels_alloc += 10; | |
238 | debug2("channel: expanding %d", channels_alloc); | |
239 | for (i = found; i < channels_alloc; i++) | |
240 | channels[i] = NULL; | |
241 | } | |
242 | /* Initialize and return new channel. */ | |
243 | c = channels[found] = xmalloc(sizeof(Channel)); | |
244 | memset(c, 0, sizeof(Channel)); | |
245 | buffer_init(&c->input); | |
246 | buffer_init(&c->output); | |
247 | buffer_init(&c->extended); | |
248 | c->ostate = CHAN_OUTPUT_OPEN; | |
249 | c->istate = CHAN_INPUT_OPEN; | |
250 | c->flags = 0; | |
251 | channel_register_fds(c, rfd, wfd, efd, extusage, nonblock); | |
252 | c->self = found; | |
253 | c->type = type; | |
254 | c->ctype = ctype; | |
255 | c->local_window = window; | |
256 | c->local_window_max = window; | |
257 | c->local_consumed = 0; | |
258 | c->local_maxpacket = maxpack; | |
259 | c->remote_id = -1; | |
260 | c->remote_name = xstrdup(remote_name); | |
261 | c->remote_window = 0; | |
262 | c->remote_maxpacket = 0; | |
263 | c->force_drain = 0; | |
264 | c->single_connection = 0; | |
265 | c->detach_user = NULL; | |
266 | c->confirm = NULL; | |
267 | c->confirm_ctx = NULL; | |
268 | c->input_filter = NULL; | |
269 | debug("channel %d: new [%s]", found, remote_name); | |
270 | return c; | |
271 | } | |
272 | ||
273 | static int | |
274 | channel_find_maxfd(void) | |
275 | { | |
276 | int i, max = 0; | |
277 | Channel *c; | |
278 | ||
279 | for (i = 0; i < channels_alloc; i++) { | |
280 | c = channels[i]; | |
281 | if (c != NULL) { | |
282 | max = MAX(max, c->rfd); | |
283 | max = MAX(max, c->wfd); | |
284 | max = MAX(max, c->efd); | |
285 | } | |
286 | } | |
287 | return max; | |
288 | } | |
289 | ||
290 | int | |
291 | channel_close_fd(int *fdp) | |
292 | { | |
293 | int ret = 0, fd = *fdp; | |
294 | ||
295 | if (fd != -1) { | |
296 | ret = close(fd); | |
297 | *fdp = -1; | |
298 | if (fd == channel_max_fd) | |
299 | channel_max_fd = channel_find_maxfd(); | |
300 | } | |
301 | return ret; | |
302 | } | |
303 | ||
304 | /* Close all channel fd/socket. */ | |
305 | ||
306 | static void | |
307 | channel_close_fds(Channel *c) | |
308 | { | |
309 | debug3("channel %d: close_fds r %d w %d e %d c %d", | |
310 | c->self, c->rfd, c->wfd, c->efd, c->ctl_fd); | |
311 | ||
312 | channel_close_fd(&c->sock); | |
313 | channel_close_fd(&c->ctl_fd); | |
314 | channel_close_fd(&c->rfd); | |
315 | channel_close_fd(&c->wfd); | |
316 | channel_close_fd(&c->efd); | |
317 | } | |
318 | ||
319 | /* Free the channel and close its fd/socket. */ | |
320 | ||
321 | void | |
322 | channel_free(Channel *c) | |
323 | { | |
324 | char *s; | |
325 | int i, n; | |
326 | ||
327 | for (n = 0, i = 0; i < channels_alloc; i++) | |
328 | if (channels[i]) | |
329 | n++; | |
330 | debug("channel %d: free: %s, nchannels %d", c->self, | |
331 | c->remote_name ? c->remote_name : "???", n); | |
332 | ||
333 | s = channel_open_message(); | |
334 | debug3("channel %d: status: %s", c->self, s); | |
335 | xfree(s); | |
336 | ||
337 | if (c->sock != -1) | |
338 | shutdown(c->sock, SHUT_RDWR); | |
339 | if (c->ctl_fd != -1) | |
340 | shutdown(c->ctl_fd, SHUT_RDWR); | |
341 | channel_close_fds(c); | |
342 | buffer_free(&c->input); | |
343 | buffer_free(&c->output); | |
344 | buffer_free(&c->extended); | |
345 | if (c->remote_name) { | |
346 | xfree(c->remote_name); | |
347 | c->remote_name = NULL; | |
348 | } | |
349 | channels[c->self] = NULL; | |
350 | xfree(c); | |
351 | } | |
352 | ||
353 | void | |
354 | channel_free_all(void) | |
355 | { | |
356 | int i; | |
357 | ||
358 | for (i = 0; i < channels_alloc; i++) | |
359 | if (channels[i] != NULL) | |
360 | channel_free(channels[i]); | |
361 | } | |
362 | ||
363 | /* | |
364 | * Closes the sockets/fds of all channels. This is used to close extra file | |
365 | * descriptors after a fork. | |
366 | */ | |
367 | ||
368 | void | |
369 | channel_close_all(void) | |
370 | { | |
371 | int i; | |
372 | ||
373 | for (i = 0; i < channels_alloc; i++) | |
374 | if (channels[i] != NULL) | |
375 | channel_close_fds(channels[i]); | |
376 | } | |
377 | ||
378 | /* | |
379 | * Stop listening to channels. | |
380 | */ | |
381 | ||
382 | void | |
383 | channel_stop_listening(void) | |
384 | { | |
385 | int i; | |
386 | Channel *c; | |
387 | ||
388 | for (i = 0; i < channels_alloc; i++) { | |
389 | c = channels[i]; | |
390 | if (c != NULL) { | |
391 | switch (c->type) { | |
392 | case SSH_CHANNEL_AUTH_SOCKET: | |
393 | case SSH_CHANNEL_PORT_LISTENER: | |
394 | case SSH_CHANNEL_RPORT_LISTENER: | |
395 | case SSH_CHANNEL_X11_LISTENER: | |
396 | channel_close_fd(&c->sock); | |
397 | channel_free(c); | |
398 | break; | |
399 | } | |
400 | } | |
401 | } | |
402 | } | |
403 | ||
404 | /* | |
405 | * Returns true if no channel has too much buffered data, and false if one or | |
406 | * more channel is overfull. | |
407 | */ | |
408 | ||
409 | int | |
410 | channel_not_very_much_buffered_data(void) | |
411 | { | |
412 | u_int i; | |
413 | Channel *c; | |
414 | ||
415 | for (i = 0; i < channels_alloc; i++) { | |
416 | c = channels[i]; | |
417 | if (c != NULL && c->type == SSH_CHANNEL_OPEN) { | |
418 | #if 0 | |
419 | if (!compat20 && | |
420 | buffer_len(&c->input) > packet_get_maxsize()) { | |
421 | debug2("channel %d: big input buffer %d", | |
422 | c->self, buffer_len(&c->input)); | |
423 | return 0; | |
424 | } | |
425 | #endif | |
426 | if (buffer_len(&c->output) > packet_get_maxsize()) { | |
427 | debug2("channel %d: big output buffer %u > %u", | |
428 | c->self, buffer_len(&c->output), | |
429 | packet_get_maxsize()); | |
430 | return 0; | |
431 | } | |
432 | } | |
433 | } | |
434 | return 1; | |
435 | } | |
436 | ||
437 | /* Returns true if any channel is still open. */ | |
438 | ||
439 | int | |
440 | channel_still_open(void) | |
441 | { | |
442 | int i; | |
443 | Channel *c; | |
444 | ||
445 | for (i = 0; i < channels_alloc; i++) { | |
446 | c = channels[i]; | |
447 | if (c == NULL) | |
448 | continue; | |
449 | switch (c->type) { | |
450 | case SSH_CHANNEL_X11_LISTENER: | |
451 | case SSH_CHANNEL_PORT_LISTENER: | |
452 | case SSH_CHANNEL_RPORT_LISTENER: | |
453 | case SSH_CHANNEL_CLOSED: | |
454 | case SSH_CHANNEL_AUTH_SOCKET: | |
455 | case SSH_CHANNEL_DYNAMIC: | |
456 | case SSH_CHANNEL_CONNECTING: | |
457 | case SSH_CHANNEL_ZOMBIE: | |
458 | continue; | |
459 | case SSH_CHANNEL_LARVAL: | |
460 | if (!compat20) | |
461 | fatal("cannot happen: SSH_CHANNEL_LARVAL"); | |
462 | continue; | |
463 | case SSH_CHANNEL_OPENING: | |
464 | case SSH_CHANNEL_OPEN: | |
465 | case SSH_CHANNEL_X11_OPEN: | |
466 | return 1; | |
467 | case SSH_CHANNEL_INPUT_DRAINING: | |
468 | case SSH_CHANNEL_OUTPUT_DRAINING: | |
469 | if (!compat13) | |
470 | fatal("cannot happen: OUT_DRAIN"); | |
471 | return 1; | |
472 | default: | |
473 | fatal("channel_still_open: bad channel type %d", c->type); | |
474 | /* NOTREACHED */ | |
475 | } | |
476 | } | |
477 | return 0; | |
478 | } | |
479 | ||
480 | /* Returns the id of an open channel suitable for keepaliving */ | |
481 | ||
482 | int | |
483 | channel_find_open(void) | |
484 | { | |
485 | int i; | |
486 | Channel *c; | |
487 | ||
488 | for (i = 0; i < channels_alloc; i++) { | |
489 | c = channels[i]; | |
490 | if (c == NULL || c->remote_id < 0) | |
491 | continue; | |
492 | switch (c->type) { | |
493 | case SSH_CHANNEL_CLOSED: | |
494 | case SSH_CHANNEL_DYNAMIC: | |
495 | case SSH_CHANNEL_X11_LISTENER: | |
496 | case SSH_CHANNEL_PORT_LISTENER: | |
497 | case SSH_CHANNEL_RPORT_LISTENER: | |
498 | case SSH_CHANNEL_OPENING: | |
499 | case SSH_CHANNEL_CONNECTING: | |
500 | case SSH_CHANNEL_ZOMBIE: | |
501 | continue; | |
502 | case SSH_CHANNEL_LARVAL: | |
503 | case SSH_CHANNEL_AUTH_SOCKET: | |
504 | case SSH_CHANNEL_OPEN: | |
505 | case SSH_CHANNEL_X11_OPEN: | |
506 | return i; | |
507 | case SSH_CHANNEL_INPUT_DRAINING: | |
508 | case SSH_CHANNEL_OUTPUT_DRAINING: | |
509 | if (!compat13) | |
510 | fatal("cannot happen: OUT_DRAIN"); | |
511 | return i; | |
512 | default: | |
513 | fatal("channel_find_open: bad channel type %d", c->type); | |
514 | /* NOTREACHED */ | |
515 | } | |
516 | } | |
517 | return -1; | |
518 | } | |
519 | ||
520 | ||
521 | /* | |
522 | * Returns a message describing the currently open forwarded connections, | |
523 | * suitable for sending to the client. The message contains crlf pairs for | |
524 | * newlines. | |
525 | */ | |
526 | ||
527 | char * | |
528 | channel_open_message(void) | |
529 | { | |
530 | Buffer buffer; | |
531 | Channel *c; | |
532 | char buf[1024], *cp; | |
533 | int i; | |
534 | ||
535 | buffer_init(&buffer); | |
536 | snprintf(buf, sizeof buf, "The following connections are open:\r\n"); | |
537 | buffer_append(&buffer, buf, strlen(buf)); | |
538 | for (i = 0; i < channels_alloc; i++) { | |
539 | c = channels[i]; | |
540 | if (c == NULL) | |
541 | continue; | |
542 | switch (c->type) { | |
543 | case SSH_CHANNEL_X11_LISTENER: | |
544 | case SSH_CHANNEL_PORT_LISTENER: | |
545 | case SSH_CHANNEL_RPORT_LISTENER: | |
546 | case SSH_CHANNEL_CLOSED: | |
547 | case SSH_CHANNEL_AUTH_SOCKET: | |
548 | case SSH_CHANNEL_ZOMBIE: | |
549 | continue; | |
550 | case SSH_CHANNEL_LARVAL: | |
551 | case SSH_CHANNEL_OPENING: | |
552 | case SSH_CHANNEL_CONNECTING: | |
553 | case SSH_CHANNEL_DYNAMIC: | |
554 | case SSH_CHANNEL_OPEN: | |
555 | case SSH_CHANNEL_X11_OPEN: | |
556 | case SSH_CHANNEL_INPUT_DRAINING: | |
557 | case SSH_CHANNEL_OUTPUT_DRAINING: | |
558 | snprintf(buf, sizeof buf, | |
559 | " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d cfd %d)\r\n", | |
560 | c->self, c->remote_name, | |
561 | c->type, c->remote_id, | |
562 | c->istate, buffer_len(&c->input), | |
563 | c->ostate, buffer_len(&c->output), | |
564 | c->rfd, c->wfd, c->ctl_fd); | |
565 | buffer_append(&buffer, buf, strlen(buf)); | |
566 | continue; | |
567 | default: | |
568 | fatal("channel_open_message: bad channel type %d", c->type); | |
569 | /* NOTREACHED */ | |
570 | } | |
571 | } | |
572 | buffer_append(&buffer, "\0", 1); | |
573 | cp = xstrdup(buffer_ptr(&buffer)); | |
574 | buffer_free(&buffer); | |
575 | return cp; | |
576 | } | |
577 | ||
578 | void | |
579 | channel_send_open(int id) | |
580 | { | |
581 | Channel *c = channel_lookup(id); | |
582 | ||
583 | if (c == NULL) { | |
584 | logit("channel_send_open: %d: bad id", id); | |
585 | return; | |
586 | } | |
587 | debug2("channel %d: send open", id); | |
588 | packet_start(SSH2_MSG_CHANNEL_OPEN); | |
589 | packet_put_cstring(c->ctype); | |
590 | packet_put_int(c->self); | |
591 | packet_put_int(c->local_window); | |
592 | packet_put_int(c->local_maxpacket); | |
593 | packet_send(); | |
594 | } | |
595 | ||
596 | void | |
597 | channel_request_start(int id, char *service, int wantconfirm) | |
598 | { | |
599 | Channel *c = channel_lookup(id); | |
600 | ||
601 | if (c == NULL) { | |
602 | logit("channel_request_start: %d: unknown channel id", id); | |
603 | return; | |
604 | } | |
605 | debug2("channel %d: request %s confirm %d", id, service, wantconfirm); | |
606 | packet_start(SSH2_MSG_CHANNEL_REQUEST); | |
607 | packet_put_int(c->remote_id); | |
608 | packet_put_cstring(service); | |
609 | packet_put_char(wantconfirm); | |
610 | } | |
611 | void | |
612 | channel_register_confirm(int id, channel_callback_fn *fn, void *ctx) | |
613 | { | |
614 | Channel *c = channel_lookup(id); | |
615 | ||
616 | if (c == NULL) { | |
617 | logit("channel_register_comfirm: %d: bad id", id); | |
618 | return; | |
619 | } | |
620 | c->confirm = fn; | |
621 | c->confirm_ctx = ctx; | |
622 | } | |
623 | void | |
624 | channel_register_cleanup(int id, channel_callback_fn *fn) | |
625 | { | |
626 | Channel *c = channel_lookup(id); | |
627 | ||
628 | if (c == NULL) { | |
629 | logit("channel_register_cleanup: %d: bad id", id); | |
630 | return; | |
631 | } | |
632 | c->detach_user = fn; | |
633 | } | |
634 | void | |
635 | channel_cancel_cleanup(int id) | |
636 | { | |
637 | Channel *c = channel_lookup(id); | |
638 | ||
639 | if (c == NULL) { | |
640 | logit("channel_cancel_cleanup: %d: bad id", id); | |
641 | return; | |
642 | } | |
643 | c->detach_user = NULL; | |
644 | } | |
645 | void | |
646 | channel_register_filter(int id, channel_filter_fn *fn) | |
647 | { | |
648 | Channel *c = channel_lookup(id); | |
649 | ||
650 | if (c == NULL) { | |
651 | logit("channel_register_filter: %d: bad id", id); | |
652 | return; | |
653 | } | |
654 | c->input_filter = fn; | |
655 | } | |
656 | ||
657 | void | |
658 | channel_set_fds(int id, int rfd, int wfd, int efd, | |
659 | int extusage, int nonblock, u_int window_max) | |
660 | { | |
661 | Channel *c = channel_lookup(id); | |
662 | ||
663 | if (c == NULL || c->type != SSH_CHANNEL_LARVAL) | |
664 | fatal("channel_activate for non-larval channel %d.", id); | |
665 | channel_register_fds(c, rfd, wfd, efd, extusage, nonblock); | |
666 | c->type = SSH_CHANNEL_OPEN; | |
667 | c->local_window = c->local_window_max = window_max; | |
668 | packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST); | |
669 | packet_put_int(c->remote_id); | |
670 | packet_put_int(c->local_window); | |
671 | packet_send(); | |
672 | } | |
673 | ||
674 | /* | |
675 | * 'channel_pre*' are called just before select() to add any bits relevant to | |
676 | * channels in the select bitmasks. | |
677 | */ | |
678 | /* | |
679 | * 'channel_post*': perform any appropriate operations for channels which | |
680 | * have events pending. | |
681 | */ | |
682 | typedef void chan_fn(Channel *c, fd_set * readset, fd_set * writeset); | |
683 | chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE]; | |
684 | chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE]; | |
685 | ||
686 | static void | |
687 | channel_pre_listener(Channel *c, fd_set * readset, fd_set * writeset) | |
688 | { | |
689 | FD_SET(c->sock, readset); | |
690 | } | |
691 | ||
692 | static void | |
693 | channel_pre_connecting(Channel *c, fd_set * readset, fd_set * writeset) | |
694 | { | |
695 | debug3("channel %d: waiting for connection", c->self); | |
696 | FD_SET(c->sock, writeset); | |
697 | } | |
698 | ||
699 | static void | |
700 | channel_pre_open_13(Channel *c, fd_set * readset, fd_set * writeset) | |
701 | { | |
702 | if (buffer_len(&c->input) < packet_get_maxsize()) | |
703 | FD_SET(c->sock, readset); | |
704 | if (buffer_len(&c->output) > 0) | |
705 | FD_SET(c->sock, writeset); | |
706 | } | |
707 | ||
708 | static void | |
709 | channel_pre_open(Channel *c, fd_set * readset, fd_set * writeset) | |
710 | { | |
711 | u_int limit = compat20 ? c->remote_window : packet_get_maxsize(); | |
712 | ||
713 | if (c->istate == CHAN_INPUT_OPEN && | |
714 | limit > 0 && | |
715 | buffer_len(&c->input) < limit) | |
716 | FD_SET(c->rfd, readset); | |
717 | if (c->ostate == CHAN_OUTPUT_OPEN || | |
718 | c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { | |
719 | if (buffer_len(&c->output) > 0) { | |
720 | FD_SET(c->wfd, writeset); | |
721 | } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { | |
722 | if (CHANNEL_EFD_OUTPUT_ACTIVE(c)) | |
723 | debug2("channel %d: obuf_empty delayed efd %d/(%d)", | |
724 | c->self, c->efd, buffer_len(&c->extended)); | |
725 | else | |
726 | chan_obuf_empty(c); | |
727 | } | |
728 | } | |
729 | /** XXX check close conditions, too */ | |
730 | if (compat20 && c->efd != -1) { | |
731 | if (c->extended_usage == CHAN_EXTENDED_WRITE && | |
732 | buffer_len(&c->extended) > 0) | |
733 | FD_SET(c->efd, writeset); | |
734 | else if (!(c->flags & CHAN_EOF_SENT) && | |
735 | c->extended_usage == CHAN_EXTENDED_READ && | |
736 | buffer_len(&c->extended) < c->remote_window) | |
737 | FD_SET(c->efd, readset); | |
738 | } | |
739 | /* XXX: What about efd? races? */ | |
740 | if (compat20 && c->ctl_fd != -1 && | |
741 | c->istate == CHAN_INPUT_OPEN && c->ostate == CHAN_OUTPUT_OPEN) | |
742 | FD_SET(c->ctl_fd, readset); | |
743 | } | |
744 | ||
745 | static void | |
746 | channel_pre_input_draining(Channel *c, fd_set * readset, fd_set * writeset) | |
747 | { | |
748 | if (buffer_len(&c->input) == 0) { | |
749 | packet_start(SSH_MSG_CHANNEL_CLOSE); | |
750 | packet_put_int(c->remote_id); | |
751 | packet_send(); | |
752 | c->type = SSH_CHANNEL_CLOSED; | |
753 | debug2("channel %d: closing after input drain.", c->self); | |
754 | } | |
755 | } | |
756 | ||
757 | static void | |
758 | channel_pre_output_draining(Channel *c, fd_set * readset, fd_set * writeset) | |
759 | { | |
760 | if (buffer_len(&c->output) == 0) | |
761 | chan_mark_dead(c); | |
762 | else | |
763 | FD_SET(c->sock, writeset); | |
764 | } | |
765 | ||
766 | /* | |
767 | * This is a special state for X11 authentication spoofing. An opened X11 | |
768 | * connection (when authentication spoofing is being done) remains in this | |
769 | * state until the first packet has been completely read. The authentication | |
770 | * data in that packet is then substituted by the real data if it matches the | |
771 | * fake data, and the channel is put into normal mode. | |
772 | * XXX All this happens at the client side. | |
773 | * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok | |
774 | */ | |
775 | static int | |
776 | x11_open_helper(Buffer *b) | |
777 | { | |
778 | u_char *ucp; | |
779 | u_int proto_len, data_len; | |
780 | ||
781 | /* Check if the fixed size part of the packet is in buffer. */ | |
782 | if (buffer_len(b) < 12) | |
783 | return 0; | |
784 | ||
785 | /* Parse the lengths of variable-length fields. */ | |
786 | ucp = buffer_ptr(b); | |
787 | if (ucp[0] == 0x42) { /* Byte order MSB first. */ | |
788 | proto_len = 256 * ucp[6] + ucp[7]; | |
789 | data_len = 256 * ucp[8] + ucp[9]; | |
790 | } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */ | |
791 | proto_len = ucp[6] + 256 * ucp[7]; | |
792 | data_len = ucp[8] + 256 * ucp[9]; | |
793 | } else { | |
794 | debug2("Initial X11 packet contains bad byte order byte: 0x%x", | |
795 | ucp[0]); | |
796 | return -1; | |
797 | } | |
798 | ||
799 | /* Check if the whole packet is in buffer. */ | |
800 | if (buffer_len(b) < | |
801 | 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3)) | |
802 | return 0; | |
803 | ||
804 | /* Check if authentication protocol matches. */ | |
805 | if (proto_len != strlen(x11_saved_proto) || | |
806 | memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) { | |
807 | debug2("X11 connection uses different authentication protocol."); | |
808 | return -1; | |
809 | } | |
810 | /* Check if authentication data matches our fake data. */ | |
811 | if (data_len != x11_fake_data_len || | |
812 | memcmp(ucp + 12 + ((proto_len + 3) & ~3), | |
813 | x11_fake_data, x11_fake_data_len) != 0) { | |
814 | debug2("X11 auth data does not match fake data."); | |
815 | return -1; | |
816 | } | |
817 | /* Check fake data length */ | |
818 | if (x11_fake_data_len != x11_saved_data_len) { | |
819 | error("X11 fake_data_len %d != saved_data_len %d", | |
820 | x11_fake_data_len, x11_saved_data_len); | |
821 | return -1; | |
822 | } | |
823 | /* | |
824 | * Received authentication protocol and data match | |
825 | * our fake data. Substitute the fake data with real | |
826 | * data. | |
827 | */ | |
828 | memcpy(ucp + 12 + ((proto_len + 3) & ~3), | |
829 | x11_saved_data, x11_saved_data_len); | |
830 | return 1; | |
831 | } | |
832 | ||
833 | static void | |
834 | channel_pre_x11_open_13(Channel *c, fd_set * readset, fd_set * writeset) | |
835 | { | |
836 | int ret = x11_open_helper(&c->output); | |
837 | ||
838 | if (ret == 1) { | |
839 | /* Start normal processing for the channel. */ | |
840 | c->type = SSH_CHANNEL_OPEN; | |
841 | channel_pre_open_13(c, readset, writeset); | |
842 | } else if (ret == -1) { | |
843 | /* | |
844 | * We have received an X11 connection that has bad | |
845 | * authentication information. | |
846 | */ | |
847 | logit("X11 connection rejected because of wrong authentication."); | |
848 | buffer_clear(&c->input); | |
849 | buffer_clear(&c->output); | |
850 | channel_close_fd(&c->sock); | |
851 | c->sock = -1; | |
852 | c->type = SSH_CHANNEL_CLOSED; | |
853 | packet_start(SSH_MSG_CHANNEL_CLOSE); | |
854 | packet_put_int(c->remote_id); | |
855 | packet_send(); | |
856 | } | |
857 | } | |
858 | ||
859 | static void | |
860 | channel_pre_x11_open(Channel *c, fd_set * readset, fd_set * writeset) | |
861 | { | |
862 | int ret = x11_open_helper(&c->output); | |
863 | ||
864 | /* c->force_drain = 1; */ | |
865 | ||
866 | if (ret == 1) { | |
867 | c->type = SSH_CHANNEL_OPEN; | |
868 | channel_pre_open(c, readset, writeset); | |
869 | } else if (ret == -1) { | |
870 | logit("X11 connection rejected because of wrong authentication."); | |
871 | debug2("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate); | |
872 | chan_read_failed(c); | |
873 | buffer_clear(&c->input); | |
874 | chan_ibuf_empty(c); | |
875 | buffer_clear(&c->output); | |
876 | /* for proto v1, the peer will send an IEOF */ | |
877 | if (compat20) | |
878 | chan_write_failed(c); | |
879 | else | |
880 | c->type = SSH_CHANNEL_OPEN; | |
881 | debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate); | |
882 | } | |
883 | } | |
884 | ||
885 | /* try to decode a socks4 header */ | |
886 | static int | |
887 | channel_decode_socks4(Channel *c, fd_set * readset, fd_set * writeset) | |
888 | { | |
889 | char *p, *host; | |
890 | int len, have, i, found; | |
891 | char username[256]; | |
892 | struct { | |
893 | u_int8_t version; | |
894 | u_int8_t command; | |
895 | u_int16_t dest_port; | |
896 | struct in_addr dest_addr; | |
897 | } s4_req, s4_rsp; | |
898 | ||
899 | debug2("channel %d: decode socks4", c->self); | |
900 | ||
901 | have = buffer_len(&c->input); | |
902 | len = sizeof(s4_req); | |
903 | if (have < len) | |
904 | return 0; | |
905 | p = buffer_ptr(&c->input); | |
906 | for (found = 0, i = len; i < have; i++) { | |
907 | if (p[i] == '\0') { | |
908 | found = 1; | |
909 | break; | |
910 | } | |
911 | if (i > 1024) { | |
912 | /* the peer is probably sending garbage */ | |
913 | debug("channel %d: decode socks4: too long", | |
914 | c->self); | |
915 | return -1; | |
916 | } | |
917 | } | |
918 | if (!found) | |
919 | return 0; | |
920 | buffer_get(&c->input, (char *)&s4_req.version, 1); | |
921 | buffer_get(&c->input, (char *)&s4_req.command, 1); | |
922 | buffer_get(&c->input, (char *)&s4_req.dest_port, 2); | |
923 | buffer_get(&c->input, (char *)&s4_req.dest_addr, 4); | |
924 | have = buffer_len(&c->input); | |
925 | p = buffer_ptr(&c->input); | |
926 | len = strlen(p); | |
927 | debug2("channel %d: decode socks4: user %s/%d", c->self, p, len); | |
928 | if (len > have) | |
929 | fatal("channel %d: decode socks4: len %d > have %d", | |
930 | c->self, len, have); | |
931 | strlcpy(username, p, sizeof(username)); | |
932 | buffer_consume(&c->input, len); | |
933 | buffer_consume(&c->input, 1); /* trailing '\0' */ | |
934 | ||
935 | host = inet_ntoa(s4_req.dest_addr); | |
936 | strlcpy(c->path, host, sizeof(c->path)); | |
937 | c->host_port = ntohs(s4_req.dest_port); | |
938 | ||
939 | debug2("channel %d: dynamic request: socks4 host %s port %u command %u", | |
940 | c->self, host, c->host_port, s4_req.command); | |
941 | ||
942 | if (s4_req.command != 1) { | |
943 | debug("channel %d: cannot handle: socks4 cn %d", | |
944 | c->self, s4_req.command); | |
945 | return -1; | |
946 | } | |
947 | s4_rsp.version = 0; /* vn: 0 for reply */ | |
948 | s4_rsp.command = 90; /* cd: req granted */ | |
949 | s4_rsp.dest_port = 0; /* ignored */ | |
950 | s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */ | |
951 | buffer_append(&c->output, (char *)&s4_rsp, sizeof(s4_rsp)); | |
952 | return 1; | |
953 | } | |
954 | ||
955 | /* try to decode a socks5 header */ | |
956 | #define SSH_SOCKS5_AUTHDONE 0x1000 | |
957 | #define SSH_SOCKS5_NOAUTH 0x00 | |
958 | #define SSH_SOCKS5_IPV4 0x01 | |
959 | #define SSH_SOCKS5_DOMAIN 0x03 | |
960 | #define SSH_SOCKS5_IPV6 0x04 | |
961 | #define SSH_SOCKS5_CONNECT 0x01 | |
962 | #define SSH_SOCKS5_SUCCESS 0x00 | |
963 | ||
964 | static int | |
965 | channel_decode_socks5(Channel *c, fd_set * readset, fd_set * writeset) | |
966 | { | |
967 | struct { | |
968 | u_int8_t version; | |
969 | u_int8_t command; | |
970 | u_int8_t reserved; | |
971 | u_int8_t atyp; | |
972 | } s5_req, s5_rsp; | |
973 | u_int16_t dest_port; | |
974 | u_char *p, dest_addr[255+1]; | |
975 | int i, have, found, nmethods, addrlen, af; | |
976 | ||
977 | debug2("channel %d: decode socks5", c->self); | |
978 | p = buffer_ptr(&c->input); | |
979 | if (p[0] != 0x05) | |
980 | return -1; | |
981 | have = buffer_len(&c->input); | |
982 | if (!(c->flags & SSH_SOCKS5_AUTHDONE)) { | |
983 | /* format: ver | nmethods | methods */ | |
984 | if (have < 2) | |
985 | return 0; | |
986 | nmethods = p[1]; | |
987 | if (have < nmethods + 2) | |
988 | return 0; | |
989 | /* look for method: "NO AUTHENTICATION REQUIRED" */ | |
990 | for (found = 0, i = 2 ; i < nmethods + 2; i++) { | |
991 | if (p[i] == SSH_SOCKS5_NOAUTH ) { | |
992 | found = 1; | |
993 | break; | |
994 | } | |
995 | } | |
996 | if (!found) { | |
997 | debug("channel %d: method SSH_SOCKS5_NOAUTH not found", | |
998 | c->self); | |
999 | return -1; | |
1000 | } | |
1001 | buffer_consume(&c->input, nmethods + 2); | |
1002 | buffer_put_char(&c->output, 0x05); /* version */ | |
1003 | buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH); /* method */ | |
1004 | FD_SET(c->sock, writeset); | |
1005 | c->flags |= SSH_SOCKS5_AUTHDONE; | |
1006 | debug2("channel %d: socks5 auth done", c->self); | |
1007 | return 0; /* need more */ | |
1008 | } | |
1009 | debug2("channel %d: socks5 post auth", c->self); | |
1010 | if (have < sizeof(s5_req)+1) | |
1011 | return 0; /* need more */ | |
1012 | memcpy((char *)&s5_req, p, sizeof(s5_req)); | |
1013 | if (s5_req.version != 0x05 || | |
1014 | s5_req.command != SSH_SOCKS5_CONNECT || | |
1015 | s5_req.reserved != 0x00) { | |
1016 | debug2("channel %d: only socks5 connect supported", c->self); | |
1017 | return -1; | |
1018 | } | |
1019 | switch(s5_req.atyp){ | |
1020 | case SSH_SOCKS5_IPV4: | |
1021 | addrlen = 4; | |
1022 | af = AF_INET; | |
1023 | break; | |
1024 | case SSH_SOCKS5_DOMAIN: | |
1025 | addrlen = p[sizeof(s5_req)]; | |
1026 | af = -1; | |
1027 | break; | |
1028 | case SSH_SOCKS5_IPV6: | |
1029 | addrlen = 16; | |
1030 | af = AF_INET6; | |
1031 | break; | |
1032 | default: | |
1033 | debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp); | |
1034 | return -1; | |
1035 | } | |
1036 | if (have < 4 + addrlen + 2) | |
1037 | return 0; | |
1038 | buffer_consume(&c->input, sizeof(s5_req)); | |
1039 | if (s5_req.atyp == SSH_SOCKS5_DOMAIN) | |
1040 | buffer_consume(&c->input, 1); /* host string length */ | |
1041 | buffer_get(&c->input, (char *)&dest_addr, addrlen); | |
1042 | buffer_get(&c->input, (char *)&dest_port, 2); | |
1043 | dest_addr[addrlen] = '\0'; | |
1044 | if (s5_req.atyp == SSH_SOCKS5_DOMAIN) | |
1045 | strlcpy(c->path, (char *)dest_addr, sizeof(c->path)); | |
1046 | else if (inet_ntop(af, dest_addr, c->path, sizeof(c->path)) == NULL) | |
1047 | return -1; | |
1048 | c->host_port = ntohs(dest_port); | |
1049 | ||
1050 | debug2("channel %d: dynamic request: socks5 host %s port %u command %u", | |
1051 | c->self, c->path, c->host_port, s5_req.command); | |
1052 | ||
1053 | s5_rsp.version = 0x05; | |
1054 | s5_rsp.command = SSH_SOCKS5_SUCCESS; | |
1055 | s5_rsp.reserved = 0; /* ignored */ | |
1056 | s5_rsp.atyp = SSH_SOCKS5_IPV4; | |
1057 | ((struct in_addr *)&dest_addr)->s_addr = INADDR_ANY; | |
1058 | dest_port = 0; /* ignored */ | |
1059 | ||
1060 | buffer_append(&c->output, (char *)&s5_rsp, sizeof(s5_rsp)); | |
1061 | buffer_append(&c->output, (char *)&dest_addr, sizeof(struct in_addr)); | |
1062 | buffer_append(&c->output, (char *)&dest_port, sizeof(dest_port)); | |
1063 | return 1; | |
1064 | } | |
1065 | ||
1066 | /* dynamic port forwarding */ | |
1067 | static void | |
1068 | channel_pre_dynamic(Channel *c, fd_set * readset, fd_set * writeset) | |
1069 | { | |
1070 | u_char *p; | |
1071 | int have, ret; | |
1072 | ||
1073 | have = buffer_len(&c->input); | |
1074 | c->delayed = 0; | |
1075 | debug2("channel %d: pre_dynamic: have %d", c->self, have); | |
1076 | /* buffer_dump(&c->input); */ | |
1077 | /* check if the fixed size part of the packet is in buffer. */ | |
1078 | if (have < 3) { | |
1079 | /* need more */ | |
1080 | FD_SET(c->sock, readset); | |
1081 | return; | |
1082 | } | |
1083 | /* try to guess the protocol */ | |
1084 | p = buffer_ptr(&c->input); | |
1085 | switch (p[0]) { | |
1086 | case 0x04: | |
1087 | ret = channel_decode_socks4(c, readset, writeset); | |
1088 | break; | |
1089 | case 0x05: | |
1090 | ret = channel_decode_socks5(c, readset, writeset); | |
1091 | break; | |
1092 | default: | |
1093 | ret = -1; | |
1094 | break; | |
1095 | } | |
1096 | if (ret < 0) { | |
1097 | chan_mark_dead(c); | |
1098 | } else if (ret == 0) { | |
1099 | debug2("channel %d: pre_dynamic: need more", c->self); | |
1100 | /* need more */ | |
1101 | FD_SET(c->sock, readset); | |
1102 | } else { | |
1103 | /* switch to the next state */ | |
1104 | c->type = SSH_CHANNEL_OPENING; | |
1105 | port_open_helper(c, "direct-tcpip"); | |
1106 | } | |
1107 | } | |
1108 | ||
1109 | /* This is our fake X11 server socket. */ | |
1110 | static void | |
1111 | channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset) | |
1112 | { | |
1113 | Channel *nc; | |
1114 | struct sockaddr addr; | |
1115 | int newsock; | |
1116 | socklen_t addrlen; | |
1117 | char buf[16384], *remote_ipaddr; | |
1118 | int remote_port; | |
1119 | ||
1120 | if (FD_ISSET(c->sock, readset)) { | |
1121 | debug("X11 connection requested."); | |
1122 | addrlen = sizeof(addr); | |
1123 | newsock = accept(c->sock, &addr, &addrlen); | |
1124 | if (c->single_connection) { | |
1125 | debug2("single_connection: closing X11 listener."); | |
1126 | channel_close_fd(&c->sock); | |
1127 | chan_mark_dead(c); | |
1128 | } | |
1129 | if (newsock < 0) { | |
1130 | error("accept: %.100s", strerror(errno)); | |
1131 | return; | |
1132 | } | |
1133 | set_nodelay(newsock); | |
1134 | remote_ipaddr = get_peer_ipaddr(newsock); | |
1135 | remote_port = get_peer_port(newsock); | |
1136 | snprintf(buf, sizeof buf, "X11 connection from %.200s port %d", | |
1137 | remote_ipaddr, remote_port); | |
1138 | ||
1139 | nc = channel_new("accepted x11 socket", | |
1140 | SSH_CHANNEL_OPENING, newsock, newsock, -1, | |
1141 | c->local_window_max, c->local_maxpacket, 0, buf, 1); | |
1142 | if (compat20) { | |
1143 | packet_start(SSH2_MSG_CHANNEL_OPEN); | |
1144 | packet_put_cstring("x11"); | |
1145 | packet_put_int(nc->self); | |
1146 | packet_put_int(nc->local_window_max); | |
1147 | packet_put_int(nc->local_maxpacket); | |
1148 | /* originator ipaddr and port */ | |
1149 | packet_put_cstring(remote_ipaddr); | |
1150 | if (datafellows & SSH_BUG_X11FWD) { | |
1151 | debug2("ssh2 x11 bug compat mode"); | |
1152 | } else { | |
1153 | packet_put_int(remote_port); | |
1154 | } | |
1155 | packet_send(); | |
1156 | } else { | |
1157 | packet_start(SSH_SMSG_X11_OPEN); | |
1158 | packet_put_int(nc->self); | |
1159 | if (packet_get_protocol_flags() & | |
1160 | SSH_PROTOFLAG_HOST_IN_FWD_OPEN) | |
1161 | packet_put_cstring(buf); | |
1162 | packet_send(); | |
1163 | } | |
1164 | xfree(remote_ipaddr); | |
1165 | } | |
1166 | } | |
1167 | ||
1168 | static void | |
1169 | port_open_helper(Channel *c, char *rtype) | |
1170 | { | |
1171 | int direct; | |
1172 | char buf[1024]; | |
1173 | char *remote_ipaddr = get_peer_ipaddr(c->sock); | |
1174 | u_short remote_port = get_peer_port(c->sock); | |
1175 | ||
1176 | direct = (strcmp(rtype, "direct-tcpip") == 0); | |
1177 | ||
1178 | snprintf(buf, sizeof buf, | |
1179 | "%s: listening port %d for %.100s port %d, " | |
1180 | "connect from %.200s port %d", | |
1181 | rtype, c->listening_port, c->path, c->host_port, | |
1182 | remote_ipaddr, remote_port); | |
1183 | ||
1184 | xfree(c->remote_name); | |
1185 | c->remote_name = xstrdup(buf); | |
1186 | ||
1187 | if (compat20) { | |
1188 | packet_start(SSH2_MSG_CHANNEL_OPEN); | |
1189 | packet_put_cstring(rtype); | |
1190 | packet_put_int(c->self); | |
1191 | packet_put_int(c->local_window_max); | |
1192 | packet_put_int(c->local_maxpacket); | |
1193 | if (direct) { | |
1194 | /* target host, port */ | |
1195 | packet_put_cstring(c->path); | |
1196 | packet_put_int(c->host_port); | |
1197 | } else { | |
1198 | /* listen address, port */ | |
1199 | packet_put_cstring(c->path); | |
1200 | packet_put_int(c->listening_port); | |
1201 | } | |
1202 | /* originator host and port */ | |
1203 | packet_put_cstring(remote_ipaddr); | |
1204 | packet_put_int(remote_port); | |
1205 | packet_send(); | |
1206 | } else { | |
1207 | packet_start(SSH_MSG_PORT_OPEN); | |
1208 | packet_put_int(c->self); | |
1209 | packet_put_cstring(c->path); | |
1210 | packet_put_int(c->host_port); | |
1211 | if (packet_get_protocol_flags() & | |
1212 | SSH_PROTOFLAG_HOST_IN_FWD_OPEN) | |
1213 | packet_put_cstring(c->remote_name); | |
1214 | packet_send(); | |
1215 | } | |
1216 | xfree(remote_ipaddr); | |
1217 | } | |
1218 | ||
1219 | /* | |
1220 | * This socket is listening for connections to a forwarded TCP/IP port. | |
1221 | */ | |
1222 | static void | |
1223 | channel_post_port_listener(Channel *c, fd_set * readset, fd_set * writeset) | |
1224 | { | |
1225 | Channel *nc; | |
1226 | struct sockaddr addr; | |
1227 | int newsock, nextstate; | |
1228 | socklen_t addrlen; | |
1229 | char *rtype; | |
1230 | ||
1231 | if (FD_ISSET(c->sock, readset)) { | |
1232 | debug("Connection to port %d forwarding " | |
1233 | "to %.100s port %d requested.", | |
1234 | c->listening_port, c->path, c->host_port); | |
1235 | ||
1236 | if (c->type == SSH_CHANNEL_RPORT_LISTENER) { | |
1237 | nextstate = SSH_CHANNEL_OPENING; | |
1238 | rtype = "forwarded-tcpip"; | |
1239 | } else { | |
1240 | if (c->host_port == 0) { | |
1241 | nextstate = SSH_CHANNEL_DYNAMIC; | |
1242 | rtype = "dynamic-tcpip"; | |
1243 | } else { | |
1244 | nextstate = SSH_CHANNEL_OPENING; | |
1245 | rtype = "direct-tcpip"; | |
1246 | } | |
1247 | } | |
1248 | ||
1249 | addrlen = sizeof(addr); | |
1250 | newsock = accept(c->sock, &addr, &addrlen); | |
1251 | if (newsock < 0) { | |
1252 | error("accept: %.100s", strerror(errno)); | |
1253 | return; | |
1254 | } | |
1255 | set_nodelay(newsock); | |
1256 | nc = channel_new(rtype, nextstate, newsock, newsock, -1, | |
1257 | c->local_window_max, c->local_maxpacket, 0, rtype, 1); | |
1258 | nc->listening_port = c->listening_port; | |
1259 | nc->host_port = c->host_port; | |
1260 | strlcpy(nc->path, c->path, sizeof(nc->path)); | |
1261 | ||
1262 | if (nextstate == SSH_CHANNEL_DYNAMIC) { | |
1263 | /* | |
1264 | * do not call the channel_post handler until | |
1265 | * this flag has been reset by a pre-handler. | |
1266 | * otherwise the FD_ISSET calls might overflow | |
1267 | */ | |
1268 | nc->delayed = 1; | |
1269 | } else { | |
1270 | port_open_helper(nc, rtype); | |
1271 | } | |
1272 | } | |
1273 | } | |
1274 | ||
1275 | /* | |
1276 | * This is the authentication agent socket listening for connections from | |
1277 | * clients. | |
1278 | */ | |
1279 | static void | |
1280 | channel_post_auth_listener(Channel *c, fd_set * readset, fd_set * writeset) | |
1281 | { | |
1282 | Channel *nc; | |
1283 | int newsock; | |
1284 | struct sockaddr addr; | |
1285 | socklen_t addrlen; | |
1286 | ||
1287 | if (FD_ISSET(c->sock, readset)) { | |
1288 | addrlen = sizeof(addr); | |
1289 | newsock = accept(c->sock, &addr, &addrlen); | |
1290 | if (newsock < 0) { | |
1291 | error("accept from auth socket: %.100s", strerror(errno)); | |
1292 | return; | |
1293 | } | |
1294 | nc = channel_new("accepted auth socket", | |
1295 | SSH_CHANNEL_OPENING, newsock, newsock, -1, | |
1296 | c->local_window_max, c->local_maxpacket, | |
1297 | 0, "accepted auth socket", 1); | |
1298 | if (compat20) { | |
1299 | packet_start(SSH2_MSG_CHANNEL_OPEN); | |
1300 | packet_put_cstring("auth-agent@openssh.com"); | |
1301 | packet_put_int(nc->self); | |
1302 | packet_put_int(c->local_window_max); | |
1303 | packet_put_int(c->local_maxpacket); | |
1304 | } else { | |
1305 | packet_start(SSH_SMSG_AGENT_OPEN); | |
1306 | packet_put_int(nc->self); | |
1307 | } | |
1308 | packet_send(); | |
1309 | } | |
1310 | } | |
1311 | ||
1312 | static void | |
1313 | channel_post_connecting(Channel *c, fd_set * readset, fd_set * writeset) | |
1314 | { | |
1315 | int err = 0; | |
1316 | socklen_t sz = sizeof(err); | |
1317 | ||
1318 | if (FD_ISSET(c->sock, writeset)) { | |
1319 | if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) { | |
1320 | err = errno; | |
1321 | error("getsockopt SO_ERROR failed"); | |
1322 | } | |
1323 | if (err == 0) { | |
1324 | debug("channel %d: connected", c->self); | |
1325 | c->type = SSH_CHANNEL_OPEN; | |
1326 | if (compat20) { | |
1327 | packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION); | |
1328 | packet_put_int(c->remote_id); | |
1329 | packet_put_int(c->self); | |
1330 | packet_put_int(c->local_window); | |
1331 | packet_put_int(c->local_maxpacket); | |
1332 | } else { | |
1333 | packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION); | |
1334 | packet_put_int(c->remote_id); | |
1335 | packet_put_int(c->self); | |
1336 | } | |
1337 | } else { | |
1338 | debug("channel %d: not connected: %s", | |
1339 | c->self, strerror(err)); | |
1340 | if (compat20) { | |
1341 | packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE); | |
1342 | packet_put_int(c->remote_id); | |
1343 | packet_put_int(SSH2_OPEN_CONNECT_FAILED); | |
1344 | if (!(datafellows & SSH_BUG_OPENFAILURE)) { | |
1345 | packet_put_cstring(strerror(err)); | |
1346 | packet_put_cstring(""); | |
1347 | } | |
1348 | } else { | |
1349 | packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); | |
1350 | packet_put_int(c->remote_id); | |
1351 | } | |
1352 | chan_mark_dead(c); | |
1353 | } | |
1354 | packet_send(); | |
1355 | } | |
1356 | } | |
1357 | ||
1358 | static int | |
1359 | channel_handle_rfd(Channel *c, fd_set * readset, fd_set * writeset) | |
1360 | { | |
1361 | char buf[16*1024]; | |
1362 | int len; | |
1363 | ||
1364 | if (c->rfd != -1 && | |
1365 | FD_ISSET(c->rfd, readset)) { | |
1366 | len = read(c->rfd, buf, sizeof(buf)); | |
1367 | if (len < 0 && (errno == EINTR || errno == EAGAIN)) | |
1368 | return 1; | |
1369 | if (len <= 0) { | |
1370 | debug2("channel %d: read<=0 rfd %d len %d", | |
1371 | c->self, c->rfd, len); | |
1372 | if (c->type != SSH_CHANNEL_OPEN) { | |
1373 | debug2("channel %d: not open", c->self); | |
1374 | chan_mark_dead(c); | |
1375 | return -1; | |
1376 | } else if (compat13) { | |
1377 | buffer_clear(&c->output); | |
1378 | c->type = SSH_CHANNEL_INPUT_DRAINING; | |
1379 | debug2("channel %d: input draining.", c->self); | |
1380 | } else { | |
1381 | chan_read_failed(c); | |
1382 | } | |
1383 | return -1; | |
1384 | } | |
1385 | if (c->input_filter != NULL) { | |
1386 | if (c->input_filter(c, buf, len) == -1) { | |
1387 | debug2("channel %d: filter stops", c->self); | |
1388 | chan_read_failed(c); | |
1389 | } | |
1390 | } else { | |
1391 | buffer_append(&c->input, buf, len); | |
1392 | } | |
1393 | } | |
1394 | return 1; | |
1395 | } | |
1396 | static int | |
1397 | channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset) | |
1398 | { | |
1399 | struct termios tio; | |
1400 | u_char *data; | |
1401 | u_int dlen; | |
1402 | int len; | |
1403 | ||
1404 | /* Send buffered output data to the socket. */ | |
1405 | if (c->wfd != -1 && | |
1406 | FD_ISSET(c->wfd, writeset) && | |
1407 | buffer_len(&c->output) > 0) { | |
1408 | data = buffer_ptr(&c->output); | |
1409 | dlen = buffer_len(&c->output); | |
1410 | #ifdef _AIX | |
1411 | /* XXX: Later AIX versions can't push as much data to tty */ | |
1412 | if (compat20 && c->wfd_isatty) | |
1413 | dlen = MIN(dlen, 8*1024); | |
1414 | #endif | |
1415 | len = write(c->wfd, data, dlen); | |
1416 | if (len < 0 && (errno == EINTR || errno == EAGAIN)) | |
1417 | return 1; | |
1418 | if (len <= 0) { | |
1419 | if (c->type != SSH_CHANNEL_OPEN) { | |
1420 | debug2("channel %d: not open", c->self); | |
1421 | chan_mark_dead(c); | |
1422 | return -1; | |
1423 | } else if (compat13) { | |
1424 | buffer_clear(&c->output); | |
1425 | debug2("channel %d: input draining.", c->self); | |
1426 | c->type = SSH_CHANNEL_INPUT_DRAINING; | |
1427 | } else { | |
1428 | chan_write_failed(c); | |
1429 | } | |
1430 | return -1; | |
1431 | } | |
1432 | if (compat20 && c->isatty && dlen >= 1 && data[0] != '\r') { | |
1433 | if (tcgetattr(c->wfd, &tio) == 0 && | |
1434 | !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) { | |
1435 | /* | |
1436 | * Simulate echo to reduce the impact of | |
1437 | * traffic analysis. We need to match the | |
1438 | * size of a SSH2_MSG_CHANNEL_DATA message | |
1439 | * (4 byte channel id + data) | |
1440 | */ | |
1441 | packet_send_ignore(4 + len); | |
1442 | packet_send(); | |
1443 | } | |
1444 | } | |
1445 | buffer_consume(&c->output, len); | |
1446 | if (compat20 && len > 0) { | |
1447 | c->local_consumed += len; | |
1448 | } | |
1449 | } | |
1450 | return 1; | |
1451 | } | |
1452 | static int | |
1453 | channel_handle_efd(Channel *c, fd_set * readset, fd_set * writeset) | |
1454 | { | |
1455 | char buf[16*1024]; | |
1456 | int len; | |
1457 | ||
1458 | /** XXX handle drain efd, too */ | |
1459 | if (c->efd != -1) { | |
1460 | if (c->extended_usage == CHAN_EXTENDED_WRITE && | |
1461 | FD_ISSET(c->efd, writeset) && | |
1462 | buffer_len(&c->extended) > 0) { | |
1463 | len = write(c->efd, buffer_ptr(&c->extended), | |
1464 | buffer_len(&c->extended)); | |
1465 | debug2("channel %d: written %d to efd %d", | |
1466 | c->self, len, c->efd); | |
1467 | if (len < 0 && (errno == EINTR || errno == EAGAIN)) | |
1468 | return 1; | |
1469 | if (len <= 0) { | |
1470 | debug2("channel %d: closing write-efd %d", | |
1471 | c->self, c->efd); | |
1472 | channel_close_fd(&c->efd); | |
1473 | } else { | |
1474 | buffer_consume(&c->extended, len); | |
1475 | c->local_consumed += len; | |
1476 | } | |
1477 | } else if (c->extended_usage == CHAN_EXTENDED_READ && | |
1478 | FD_ISSET(c->efd, readset)) { | |
1479 | len = read(c->efd, buf, sizeof(buf)); | |
1480 | debug2("channel %d: read %d from efd %d", | |
1481 | c->self, len, c->efd); | |
1482 | if (len < 0 && (errno == EINTR || errno == EAGAIN)) | |
1483 | return 1; | |
1484 | if (len <= 0) { | |
1485 | debug2("channel %d: closing read-efd %d", | |
1486 | c->self, c->efd); | |
1487 | channel_close_fd(&c->efd); | |
1488 | } else { | |
1489 | buffer_append(&c->extended, buf, len); | |
1490 | } | |
1491 | } | |
1492 | } | |
1493 | return 1; | |
1494 | } | |
1495 | static int | |
1496 | channel_handle_ctl(Channel *c, fd_set * readset, fd_set * writeset) | |
1497 | { | |
1498 | char buf[16]; | |
1499 | int len; | |
1500 | ||
1501 | /* Monitor control fd to detect if the slave client exits */ | |
1502 | if (c->ctl_fd != -1 && FD_ISSET(c->ctl_fd, readset)) { | |
1503 | len = read(c->ctl_fd, buf, sizeof(buf)); | |
1504 | if (len < 0 && (errno == EINTR || errno == EAGAIN)) | |
1505 | return 1; | |
1506 | if (len <= 0) { | |
1507 | debug2("channel %d: ctl read<=0", c->self); | |
1508 | if (c->type != SSH_CHANNEL_OPEN) { | |
1509 | debug2("channel %d: not open", c->self); | |
1510 | chan_mark_dead(c); | |
1511 | return -1; | |
1512 | } else { | |
1513 | chan_read_failed(c); | |
1514 | chan_write_failed(c); | |
1515 | } | |
1516 | return -1; | |
1517 | } else | |
1518 | fatal("%s: unexpected data on ctl fd", __func__); | |
1519 | } | |
1520 | return 1; | |
1521 | } | |
1522 | static int | |
1523 | channel_check_window(Channel *c) | |
1524 | { | |
1525 | if (c->type == SSH_CHANNEL_OPEN && | |
1526 | !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) && | |
1527 | c->local_window < c->local_window_max/2 && | |
1528 | c->local_consumed > 0) { | |
1529 | packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST); | |
1530 | packet_put_int(c->remote_id); | |
1531 | packet_put_int(c->local_consumed); | |
1532 | packet_send(); | |
1533 | debug2("channel %d: window %d sent adjust %d", | |
1534 | c->self, c->local_window, | |
1535 | c->local_consumed); | |
1536 | c->local_window += c->local_consumed; | |
1537 | c->local_consumed = 0; | |
1538 | } | |
1539 | return 1; | |
1540 | } | |
1541 | ||
1542 | static void | |
1543 | channel_post_open(Channel *c, fd_set * readset, fd_set * writeset) | |
1544 | { | |
1545 | if (c->delayed) | |
1546 | return; | |
1547 | channel_handle_rfd(c, readset, writeset); | |
1548 | channel_handle_wfd(c, readset, writeset); | |
1549 | if (!compat20) | |
1550 | return; | |
1551 | channel_handle_efd(c, readset, writeset); | |
1552 | channel_handle_ctl(c, readset, writeset); | |
1553 | channel_check_window(c); | |
1554 | } | |
1555 | ||
1556 | static void | |
1557 | channel_post_output_drain_13(Channel *c, fd_set * readset, fd_set * writeset) | |
1558 | { | |
1559 | int len; | |
1560 | ||
1561 | /* Send buffered output data to the socket. */ | |
1562 | if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) { | |
1563 | len = write(c->sock, buffer_ptr(&c->output), | |
1564 | buffer_len(&c->output)); | |
1565 | if (len <= 0) | |
1566 | buffer_clear(&c->output); | |
1567 | else | |
1568 | buffer_consume(&c->output, len); | |
1569 | } | |
1570 | } | |
1571 | ||
1572 | static void | |
1573 | channel_handler_init_20(void) | |
1574 | { | |
1575 | channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open; | |
1576 | channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; | |
1577 | channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; | |
1578 | channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener; | |
1579 | channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; | |
1580 | channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; | |
1581 | channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; | |
1582 | channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; | |
1583 | ||
1584 | channel_post[SSH_CHANNEL_OPEN] = &channel_post_open; | |
1585 | channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; | |
1586 | channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener; | |
1587 | channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; | |
1588 | channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; | |
1589 | channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; | |
1590 | channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; | |
1591 | } | |
1592 | ||
1593 | static void | |
1594 | channel_handler_init_13(void) | |
1595 | { | |
1596 | channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13; | |
1597 | channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13; | |
1598 | channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; | |
1599 | channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; | |
1600 | channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; | |
1601 | channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining; | |
1602 | channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining; | |
1603 | channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; | |
1604 | channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; | |
1605 | ||
1606 | channel_post[SSH_CHANNEL_OPEN] = &channel_post_open; | |
1607 | channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; | |
1608 | channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; | |
1609 | channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; | |
1610 | channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13; | |
1611 | channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; | |
1612 | channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; | |
1613 | } | |
1614 | ||
1615 | static void | |
1616 | channel_handler_init_15(void) | |
1617 | { | |
1618 | channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open; | |
1619 | channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; | |
1620 | channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; | |
1621 | channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; | |
1622 | channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; | |
1623 | channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; | |
1624 | channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; | |
1625 | ||
1626 | channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; | |
1627 | channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; | |
1628 | channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; | |
1629 | channel_post[SSH_CHANNEL_OPEN] = &channel_post_open; | |
1630 | channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; | |
1631 | channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; | |
1632 | } | |
1633 | ||
1634 | static void | |
1635 | channel_handler_init(void) | |
1636 | { | |
1637 | int i; | |
1638 | ||
1639 | for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) { | |
1640 | channel_pre[i] = NULL; | |
1641 | channel_post[i] = NULL; | |
1642 | } | |
1643 | if (compat20) | |
1644 | channel_handler_init_20(); | |
1645 | else if (compat13) | |
1646 | channel_handler_init_13(); | |
1647 | else | |
1648 | channel_handler_init_15(); | |
1649 | } | |
1650 | ||
1651 | /* gc dead channels */ | |
1652 | static void | |
1653 | channel_garbage_collect(Channel *c) | |
1654 | { | |
1655 | if (c == NULL) | |
1656 | return; | |
1657 | if (c->detach_user != NULL) { | |
1658 | if (!chan_is_dead(c, 0)) | |
1659 | return; | |
1660 | debug2("channel %d: gc: notify user", c->self); | |
1661 | c->detach_user(c->self, NULL); | |
1662 | /* if we still have a callback */ | |
1663 | if (c->detach_user != NULL) | |
1664 | return; | |
1665 | debug2("channel %d: gc: user detached", c->self); | |
1666 | } | |
1667 | if (!chan_is_dead(c, 1)) | |
1668 | return; | |
1669 | debug2("channel %d: garbage collecting", c->self); | |
1670 | channel_free(c); | |
1671 | } | |
1672 | ||
1673 | static void | |
1674 | channel_handler(chan_fn *ftab[], fd_set * readset, fd_set * writeset) | |
1675 | { | |
1676 | static int did_init = 0; | |
1677 | int i; | |
1678 | Channel *c; | |
1679 | ||
1680 | if (!did_init) { | |
1681 | channel_handler_init(); | |
1682 | did_init = 1; | |
1683 | } | |
1684 | for (i = 0; i < channels_alloc; i++) { | |
1685 | c = channels[i]; | |
1686 | if (c == NULL) | |
1687 | continue; | |
1688 | if (ftab[c->type] != NULL) | |
1689 | (*ftab[c->type])(c, readset, writeset); | |
1690 | channel_garbage_collect(c); | |
1691 | } | |
1692 | } | |
1693 | ||
1694 | /* | |
1695 | * Allocate/update select bitmasks and add any bits relevant to channels in | |
1696 | * select bitmasks. | |
1697 | */ | |
1698 | void | |
1699 | channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp, | |
1700 | int *nallocp, int rekeying) | |
1701 | { | |
1702 | int n; | |
1703 | u_int sz; | |
1704 | ||
1705 | n = MAX(*maxfdp, channel_max_fd); | |
1706 | ||
1707 | sz = howmany(n+1, NFDBITS) * sizeof(fd_mask); | |
1708 | /* perhaps check sz < nalloc/2 and shrink? */ | |
1709 | if (*readsetp == NULL || sz > *nallocp) { | |
1710 | *readsetp = xrealloc(*readsetp, sz); | |
1711 | *writesetp = xrealloc(*writesetp, sz); | |
1712 | *nallocp = sz; | |
1713 | } | |
1714 | *maxfdp = n; | |
1715 | memset(*readsetp, 0, sz); | |
1716 | memset(*writesetp, 0, sz); | |
1717 | ||
1718 | if (!rekeying) | |
1719 | channel_handler(channel_pre, *readsetp, *writesetp); | |
1720 | } | |
1721 | ||
1722 | /* | |
1723 | * After select, perform any appropriate operations for channels which have | |
1724 | * events pending. | |
1725 | */ | |
1726 | void | |
1727 | channel_after_select(fd_set * readset, fd_set * writeset) | |
1728 | { | |
1729 | channel_handler(channel_post, readset, writeset); | |
1730 | } | |
1731 | ||
1732 | ||
1733 | /* If there is data to send to the connection, enqueue some of it now. */ | |
1734 | ||
1735 | void | |
1736 | channel_output_poll(void) | |
1737 | { | |
1738 | Channel *c; | |
1739 | int i; | |
1740 | u_int len; | |
1741 | ||
1742 | for (i = 0; i < channels_alloc; i++) { | |
1743 | c = channels[i]; | |
1744 | if (c == NULL) | |
1745 | continue; | |
1746 | ||
1747 | /* | |
1748 | * We are only interested in channels that can have buffered | |
1749 | * incoming data. | |
1750 | */ | |
1751 | if (compat13) { | |
1752 | if (c->type != SSH_CHANNEL_OPEN && | |
1753 | c->type != SSH_CHANNEL_INPUT_DRAINING) | |
1754 | continue; | |
1755 | } else { | |
1756 | if (c->type != SSH_CHANNEL_OPEN) | |
1757 | continue; | |
1758 | } | |
1759 | if (compat20 && | |
1760 | (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) { | |
1761 | /* XXX is this true? */ | |
1762 | debug3("channel %d: will not send data after close", c->self); | |
1763 | continue; | |
1764 | } | |
1765 | ||
1766 | /* Get the amount of buffered data for this channel. */ | |
1767 | if ((c->istate == CHAN_INPUT_OPEN || | |
1768 | c->istate == CHAN_INPUT_WAIT_DRAIN) && | |
1769 | (len = buffer_len(&c->input)) > 0) { | |
1770 | /* | |
1771 | * Send some data for the other side over the secure | |
1772 | * connection. | |
1773 | */ | |
1774 | if (compat20) { | |
1775 | if (len > c->remote_window) | |
1776 | len = c->remote_window; | |
1777 | if (len > c->remote_maxpacket) | |
1778 | len = c->remote_maxpacket; | |
1779 | } else { | |
1780 | if (packet_is_interactive()) { | |
1781 | if (len > 1024) | |
1782 | len = 512; | |
1783 | } else { | |
1784 | /* Keep the packets at reasonable size. */ | |
1785 | if (len > packet_get_maxsize()/2) | |
1786 | len = packet_get_maxsize()/2; | |
1787 | } | |
1788 | } | |
1789 | if (len > 0) { | |
1790 | packet_start(compat20 ? | |
1791 | SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA); | |
1792 | packet_put_int(c->remote_id); | |
1793 | packet_put_string(buffer_ptr(&c->input), len); | |
1794 | packet_send(); | |
1795 | buffer_consume(&c->input, len); | |
1796 | c->remote_window -= len; | |
1797 | } | |
1798 | } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) { | |
1799 | if (compat13) | |
1800 | fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3"); | |
1801 | /* | |
1802 | * input-buffer is empty and read-socket shutdown: | |
1803 | * tell peer, that we will not send more data: send IEOF. | |
1804 | * hack for extended data: delay EOF if EFD still in use. | |
1805 | */ | |
1806 | if (CHANNEL_EFD_INPUT_ACTIVE(c)) | |
1807 | debug2("channel %d: ibuf_empty delayed efd %d/(%d)", | |
1808 | c->self, c->efd, buffer_len(&c->extended)); | |
1809 | else | |
1810 | chan_ibuf_empty(c); | |
1811 | } | |
1812 | /* Send extended data, i.e. stderr */ | |
1813 | if (compat20 && | |
1814 | !(c->flags & CHAN_EOF_SENT) && | |
1815 | c->remote_window > 0 && | |
1816 | (len = buffer_len(&c->extended)) > 0 && | |
1817 | c->extended_usage == CHAN_EXTENDED_READ) { | |
1818 | debug2("channel %d: rwin %u elen %u euse %d", | |
1819 | c->self, c->remote_window, buffer_len(&c->extended), | |
1820 | c->extended_usage); | |
1821 | if (len > c->remote_window) | |
1822 | len = c->remote_window; | |
1823 | if (len > c->remote_maxpacket) | |
1824 | len = c->remote_maxpacket; | |
1825 | packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA); | |
1826 | packet_put_int(c->remote_id); | |
1827 | packet_put_int(SSH2_EXTENDED_DATA_STDERR); | |
1828 | packet_put_string(buffer_ptr(&c->extended), len); | |
1829 | packet_send(); | |
1830 | buffer_consume(&c->extended, len); | |
1831 | c->remote_window -= len; | |
1832 | debug2("channel %d: sent ext data %d", c->self, len); | |
1833 | } | |
1834 | } | |
1835 | } | |
1836 | ||
1837 | ||
1838 | /* -- protocol input */ | |
1839 | ||
1840 | void | |
1841 | channel_input_data(int type, u_int32_t seq, void *ctxt) | |
1842 | { | |
1843 | int id; | |
1844 | char *data; | |
1845 | u_int data_len; | |
1846 | Channel *c; | |
1847 | ||
1848 | /* Get the channel number and verify it. */ | |
1849 | id = packet_get_int(); | |
1850 | c = channel_lookup(id); | |
1851 | if (c == NULL) | |
1852 | packet_disconnect("Received data for nonexistent channel %d.", id); | |
1853 | ||
1854 | /* Ignore any data for non-open channels (might happen on close) */ | |
1855 | if (c->type != SSH_CHANNEL_OPEN && | |
1856 | c->type != SSH_CHANNEL_X11_OPEN) | |
1857 | return; | |
1858 | ||
1859 | /* Get the data. */ | |
1860 | data = packet_get_string(&data_len); | |
1861 | ||
1862 | /* | |
1863 | * Ignore data for protocol > 1.3 if output end is no longer open. | |
1864 | * For protocol 2 the sending side is reducing its window as it sends | |
1865 | * data, so we must 'fake' consumption of the data in order to ensure | |
1866 | * that window updates are sent back. Otherwise the connection might | |
1867 | * deadlock. | |
1868 | */ | |
1869 | if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) { | |
1870 | if (compat20) { | |
1871 | c->local_window -= data_len; | |
1872 | c->local_consumed += data_len; | |
1873 | } | |
1874 | xfree(data); | |
1875 | return; | |
1876 | } | |
1877 | ||
1878 | if (compat20) { | |
1879 | if (data_len > c->local_maxpacket) { | |
1880 | logit("channel %d: rcvd big packet %d, maxpack %d", | |
1881 | c->self, data_len, c->local_maxpacket); | |
1882 | } | |
1883 | if (data_len > c->local_window) { | |
1884 | logit("channel %d: rcvd too much data %d, win %d", | |
1885 | c->self, data_len, c->local_window); | |
1886 | xfree(data); | |
1887 | return; | |
1888 | } | |
1889 | c->local_window -= data_len; | |
1890 | } | |
1891 | packet_check_eom(); | |
1892 | buffer_append(&c->output, data, data_len); | |
1893 | xfree(data); | |
1894 | } | |
1895 | ||
1896 | void | |
1897 | channel_input_extended_data(int type, u_int32_t seq, void *ctxt) | |
1898 | { | |
1899 | int id; | |
1900 | char *data; | |
1901 | u_int data_len, tcode; | |
1902 | Channel *c; | |
1903 | ||
1904 | /* Get the channel number and verify it. */ | |
1905 | id = packet_get_int(); | |
1906 | c = channel_lookup(id); | |
1907 | ||
1908 | if (c == NULL) | |
1909 | packet_disconnect("Received extended_data for bad channel %d.", id); | |
1910 | if (c->type != SSH_CHANNEL_OPEN) { | |
1911 | logit("channel %d: ext data for non open", id); | |
1912 | return; | |
1913 | } | |
1914 | if (c->flags & CHAN_EOF_RCVD) { | |
1915 | if (datafellows & SSH_BUG_EXTEOF) | |
1916 | debug("channel %d: accepting ext data after eof", id); | |
1917 | else | |
1918 | packet_disconnect("Received extended_data after EOF " | |
1919 | "on channel %d.", id); | |
1920 | } | |
1921 | tcode = packet_get_int(); | |
1922 | if (c->efd == -1 || | |
1923 | c->extended_usage != CHAN_EXTENDED_WRITE || | |
1924 | tcode != SSH2_EXTENDED_DATA_STDERR) { | |
1925 | logit("channel %d: bad ext data", c->self); | |
1926 | return; | |
1927 | } | |
1928 | data = packet_get_string(&data_len); | |
1929 | packet_check_eom(); | |
1930 | if (data_len > c->local_window) { | |
1931 | logit("channel %d: rcvd too much extended_data %d, win %d", | |
1932 | c->self, data_len, c->local_window); | |
1933 | xfree(data); | |
1934 | return; | |
1935 | } | |
1936 | debug2("channel %d: rcvd ext data %d", c->self, data_len); | |
1937 | c->local_window -= data_len; | |
1938 | buffer_append(&c->extended, data, data_len); | |
1939 | xfree(data); | |
1940 | } | |
1941 | ||
1942 | void | |
1943 | channel_input_ieof(int type, u_int32_t seq, void *ctxt) | |
1944 | { | |
1945 | int id; | |
1946 | Channel *c; | |
1947 | ||
1948 | id = packet_get_int(); | |
1949 | packet_check_eom(); | |
1950 | c = channel_lookup(id); | |
1951 | if (c == NULL) | |
1952 | packet_disconnect("Received ieof for nonexistent channel %d.", id); | |
1953 | chan_rcvd_ieof(c); | |
1954 | ||
1955 | /* XXX force input close */ | |
1956 | if (c->force_drain && c->istate == CHAN_INPUT_OPEN) { | |
1957 | debug("channel %d: FORCE input drain", c->self); | |
1958 | c->istate = CHAN_INPUT_WAIT_DRAIN; | |
1959 | if (buffer_len(&c->input) == 0) | |
1960 | chan_ibuf_empty(c); | |
1961 | } | |
1962 | ||
1963 | } | |
1964 | ||
1965 | void | |
1966 | channel_input_close(int type, u_int32_t seq, void *ctxt) | |
1967 | { | |
1968 | int id; | |
1969 | Channel *c; | |
1970 | ||
1971 | id = packet_get_int(); | |
1972 | packet_check_eom(); | |
1973 | c = channel_lookup(id); | |
1974 | if (c == NULL) | |
1975 | packet_disconnect("Received close for nonexistent channel %d.", id); | |
1976 | ||
1977 | /* | |
1978 | * Send a confirmation that we have closed the channel and no more | |
1979 | * data is coming for it. | |
1980 | */ | |
1981 | packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION); | |
1982 | packet_put_int(c->remote_id); | |
1983 | packet_send(); | |
1984 | ||
1985 | /* | |
1986 | * If the channel is in closed state, we have sent a close request, | |
1987 | * and the other side will eventually respond with a confirmation. | |
1988 | * Thus, we cannot free the channel here, because then there would be | |
1989 | * no-one to receive the confirmation. The channel gets freed when | |
1990 | * the confirmation arrives. | |
1991 | */ | |
1992 | if (c->type != SSH_CHANNEL_CLOSED) { | |
1993 | /* | |
1994 | * Not a closed channel - mark it as draining, which will | |
1995 | * cause it to be freed later. | |
1996 | */ | |
1997 | buffer_clear(&c->input); | |
1998 | c->type = SSH_CHANNEL_OUTPUT_DRAINING; | |
1999 | } | |
2000 | } | |
2001 | ||
2002 | /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */ | |
2003 | void | |
2004 | channel_input_oclose(int type, u_int32_t seq, void *ctxt) | |
2005 | { | |
2006 | int id = packet_get_int(); | |
2007 | Channel *c = channel_lookup(id); | |
2008 | ||
2009 | packet_check_eom(); | |
2010 | if (c == NULL) | |
2011 | packet_disconnect("Received oclose for nonexistent channel %d.", id); | |
2012 | chan_rcvd_oclose(c); | |
2013 | } | |
2014 | ||
2015 | void | |
2016 | channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt) | |
2017 | { | |
2018 | int id = packet_get_int(); | |
2019 | Channel *c = channel_lookup(id); | |
2020 | ||
2021 | packet_check_eom(); | |
2022 | if (c == NULL) | |
2023 | packet_disconnect("Received close confirmation for " | |
2024 | "out-of-range channel %d.", id); | |
2025 | if (c->type != SSH_CHANNEL_CLOSED) | |
2026 | packet_disconnect("Received close confirmation for " | |
2027 | "non-closed channel %d (type %d).", id, c->type); | |
2028 | channel_free(c); | |
2029 | } | |
2030 | ||
2031 | void | |
2032 | channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt) | |
2033 | { | |
2034 | int id, remote_id; | |
2035 | Channel *c; | |
2036 | ||
2037 | id = packet_get_int(); | |
2038 | c = channel_lookup(id); | |
2039 | ||
2040 | if (c==NULL || c->type != SSH_CHANNEL_OPENING) | |
2041 | packet_disconnect("Received open confirmation for " | |
2042 | "non-opening channel %d.", id); | |
2043 | remote_id = packet_get_int(); | |
2044 | /* Record the remote channel number and mark that the channel is now open. */ | |
2045 | c->remote_id = remote_id; | |
2046 | c->type = SSH_CHANNEL_OPEN; | |
2047 | ||
2048 | if (compat20) { | |
2049 | c->remote_window = packet_get_int(); | |
2050 | c->remote_maxpacket = packet_get_int(); | |
2051 | if (c->confirm) { | |
2052 | debug2("callback start"); | |
2053 | c->confirm(c->self, c->confirm_ctx); | |
2054 | debug2("callback done"); | |
2055 | } | |
2056 | debug2("channel %d: open confirm rwindow %u rmax %u", c->self, | |
2057 | c->remote_window, c->remote_maxpacket); | |
2058 | } | |
2059 | packet_check_eom(); | |
2060 | } | |
2061 | ||
2062 | static char * | |
2063 | reason2txt(int reason) | |
2064 | { | |
2065 | switch (reason) { | |
2066 | case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED: | |
2067 | return "administratively prohibited"; | |
2068 | case SSH2_OPEN_CONNECT_FAILED: | |
2069 | return "connect failed"; | |
2070 | case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE: | |
2071 | return "unknown channel type"; | |
2072 | case SSH2_OPEN_RESOURCE_SHORTAGE: | |
2073 | return "resource shortage"; | |
2074 | } | |
2075 | return "unknown reason"; | |
2076 | } | |
2077 | ||
2078 | void | |
2079 | channel_input_open_failure(int type, u_int32_t seq, void *ctxt) | |
2080 | { | |
2081 | int id, reason; | |
2082 | char *msg = NULL, *lang = NULL; | |
2083 | Channel *c; | |
2084 | ||
2085 | id = packet_get_int(); | |
2086 | c = channel_lookup(id); | |
2087 | ||
2088 | if (c==NULL || c->type != SSH_CHANNEL_OPENING) | |
2089 | packet_disconnect("Received open failure for " | |
2090 | "non-opening channel %d.", id); | |
2091 | if (compat20) { | |
2092 | reason = packet_get_int(); | |
2093 | if (!(datafellows & SSH_BUG_OPENFAILURE)) { | |
2094 | msg = packet_get_string(NULL); | |
2095 | lang = packet_get_string(NULL); | |
2096 | } | |
2097 | logit("channel %d: open failed: %s%s%s", id, | |
2098 | reason2txt(reason), msg ? ": ": "", msg ? msg : ""); | |
2099 | if (msg != NULL) | |
2100 | xfree(msg); | |
2101 | if (lang != NULL) | |
2102 | xfree(lang); | |
2103 | } | |
2104 | packet_check_eom(); | |
2105 | /* Free the channel. This will also close the socket. */ | |
2106 | channel_free(c); | |
2107 | } | |
2108 | ||
2109 | void | |
2110 | channel_input_window_adjust(int type, u_int32_t seq, void *ctxt) | |
2111 | { | |
2112 | Channel *c; | |
2113 | int id; | |
2114 | u_int adjust; | |
2115 | ||
2116 | if (!compat20) | |
2117 | return; | |
2118 | ||
2119 | /* Get the channel number and verify it. */ | |
2120 | id = packet_get_int(); | |
2121 | c = channel_lookup(id); | |
2122 | ||
2123 | if (c == NULL || c->type != SSH_CHANNEL_OPEN) { | |
2124 | logit("Received window adjust for " | |
2125 | "non-open channel %d.", id); | |
2126 | return; | |
2127 | } | |
2128 | adjust = packet_get_int(); | |
2129 | packet_check_eom(); | |
2130 | debug2("channel %d: rcvd adjust %u", id, adjust); | |
2131 | c->remote_window += adjust; | |
2132 | } | |
2133 | ||
2134 | void | |
2135 | channel_input_port_open(int type, u_int32_t seq, void *ctxt) | |
2136 | { | |
2137 | Channel *c = NULL; | |
2138 | u_short host_port; | |
2139 | char *host, *originator_string; | |
2140 | int remote_id, sock = -1; | |
2141 | ||
2142 | remote_id = packet_get_int(); | |
2143 | host = packet_get_string(NULL); | |
2144 | host_port = packet_get_int(); | |
2145 | ||
2146 | if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) { | |
2147 | originator_string = packet_get_string(NULL); | |
2148 | } else { | |
2149 | originator_string = xstrdup("unknown (remote did not supply name)"); | |
2150 | } | |
2151 | packet_check_eom(); | |
2152 | sock = channel_connect_to(host, host_port); | |
2153 | if (sock != -1) { | |
2154 | c = channel_new("connected socket", | |
2155 | SSH_CHANNEL_CONNECTING, sock, sock, -1, 0, 0, 0, | |
2156 | originator_string, 1); | |
2157 | c->remote_id = remote_id; | |
2158 | } | |
2159 | xfree(originator_string); | |
2160 | if (c == NULL) { | |
2161 | packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); | |
2162 | packet_put_int(remote_id); | |
2163 | packet_send(); | |
2164 | } | |
2165 | xfree(host); | |
2166 | } | |
2167 | ||
2168 | ||
2169 | /* -- tcp forwarding */ | |
2170 | ||
2171 | void | |
2172 | channel_set_af(int af) | |
2173 | { | |
2174 | IPv4or6 = af; | |
2175 | } | |
2176 | ||
2177 | static int | |
2178 | channel_setup_fwd_listener(int type, const char *listen_addr, u_short listen_port, | |
2179 | const char *host_to_connect, u_short port_to_connect, int gateway_ports) | |
2180 | { | |
2181 | Channel *c; | |
2182 | int success, sock, on = 1; | |
2183 | struct addrinfo hints, *ai, *aitop; | |
2184 | const char *host; | |
2185 | char ntop[NI_MAXHOST], strport[NI_MAXSERV]; | |
2186 | ||
2187 | success = 0; | |
2188 | host = (type == SSH_CHANNEL_RPORT_LISTENER) ? | |
2189 | listen_addr : host_to_connect; | |
2190 | ||
2191 | if (host == NULL) { | |
2192 | error("No forward host name."); | |
2193 | return success; | |
2194 | } | |
2195 | if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) { | |
2196 | error("Forward host name too long."); | |
2197 | return success; | |
2198 | } | |
2199 | ||
2200 | /* | |
2201 | * getaddrinfo returns a loopback address if the hostname is | |
2202 | * set to NULL and hints.ai_flags is not AI_PASSIVE | |
2203 | */ | |
2204 | memset(&hints, 0, sizeof(hints)); | |
2205 | hints.ai_family = IPv4or6; | |
2206 | hints.ai_flags = gateway_ports ? AI_PASSIVE : 0; | |
2207 | hints.ai_socktype = SOCK_STREAM; | |
2208 | snprintf(strport, sizeof strport, "%d", listen_port); | |
2209 | if (getaddrinfo(NULL, strport, &hints, &aitop) != 0) | |
2210 | packet_disconnect("getaddrinfo: fatal error"); | |
2211 | ||
2212 | for (ai = aitop; ai; ai = ai->ai_next) { | |
2213 | if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) | |
2214 | continue; | |
2215 | if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), | |
2216 | strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) { | |
2217 | error("channel_setup_fwd_listener: getnameinfo failed"); | |
2218 | continue; | |
2219 | } | |
2220 | /* Create a port to listen for the host. */ | |
2221 | sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); | |
2222 | if (sock < 0) { | |
2223 | /* this is no error since kernel may not support ipv6 */ | |
2224 | verbose("socket: %.100s", strerror(errno)); | |
2225 | continue; | |
2226 | } | |
2227 | /* | |
2228 | * Set socket options. | |
2229 | * Allow local port reuse in TIME_WAIT. | |
2230 | */ | |
2231 | if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &on, | |
2232 | sizeof(on)) == -1) | |
2233 | error("setsockopt SO_REUSEADDR: %s", strerror(errno)); | |
2234 | ||
2235 | debug("Local forwarding listening on %s port %s.", ntop, strport); | |
2236 | ||
2237 | /* Bind the socket to the address. */ | |
2238 | if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) { | |
2239 | /* address can be in use ipv6 address is already bound */ | |
2240 | if (!ai->ai_next) | |
2241 | error("bind: %.100s", strerror(errno)); | |
2242 | else | |
2243 | verbose("bind: %.100s", strerror(errno)); | |
2244 | ||
2245 | close(sock); | |
2246 | continue; | |
2247 | } | |
2248 | /* Start listening for connections on the socket. */ | |
2249 | if (listen(sock, SSH_LISTEN_BACKLOG) < 0) { | |
2250 | error("listen: %.100s", strerror(errno)); | |
2251 | close(sock); | |
2252 | continue; | |
2253 | } | |
2254 | /* Allocate a channel number for the socket. */ | |
2255 | c = channel_new("port listener", type, sock, sock, -1, | |
2256 | CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, | |
2257 | 0, "port listener", 1); | |
2258 | strlcpy(c->path, host, sizeof(c->path)); | |
2259 | c->host_port = port_to_connect; | |
2260 | c->listening_port = listen_port; | |
2261 | success = 1; | |
2262 | } | |
2263 | if (success == 0) | |
2264 | error("channel_setup_fwd_listener: cannot listen to port: %d", | |
2265 | listen_port); | |
2266 | freeaddrinfo(aitop); | |
2267 | return success; | |
2268 | } | |
2269 | ||
2270 | int | |
2271 | channel_cancel_rport_listener(const char *host, u_short port) | |
2272 | { | |
2273 | int i, found = 0; | |
2274 | ||
2275 | for(i = 0; i < channels_alloc; i++) { | |
2276 | Channel *c = channels[i]; | |
2277 | ||
2278 | if (c != NULL && c->type == SSH_CHANNEL_RPORT_LISTENER && | |
2279 | strncmp(c->path, host, sizeof(c->path)) == 0 && | |
2280 | c->listening_port == port) { | |
2281 | debug2("%s: close clannel %d", __func__, i); | |
2282 | channel_free(c); | |
2283 | found = 1; | |
2284 | } | |
2285 | } | |
2286 | ||
2287 | return (found); | |
2288 | } | |
2289 | ||
2290 | /* protocol local port fwd, used by ssh (and sshd in v1) */ | |
2291 | int | |
2292 | channel_setup_local_fwd_listener(u_short listen_port, | |
2293 | const char *host_to_connect, u_short port_to_connect, int gateway_ports) | |
2294 | { | |
2295 | return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER, | |
2296 | NULL, listen_port, host_to_connect, port_to_connect, gateway_ports); | |
2297 | } | |
2298 | ||
2299 | /* protocol v2 remote port fwd, used by sshd */ | |
2300 | int | |
2301 | channel_setup_remote_fwd_listener(const char *listen_address, | |
2302 | u_short listen_port, int gateway_ports) | |
2303 | { | |
2304 | return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER, | |
2305 | listen_address, listen_port, NULL, 0, gateway_ports); | |
2306 | } | |
2307 | ||
2308 | /* | |
2309 | * Initiate forwarding of connections to port "port" on remote host through | |
2310 | * the secure channel to host:port from local side. | |
2311 | */ | |
2312 | ||
2313 | void | |
2314 | channel_request_remote_forwarding(u_short listen_port, | |
2315 | const char *host_to_connect, u_short port_to_connect) | |
2316 | { | |
2317 | int type, success = 0; | |
2318 | ||
2319 | /* Record locally that connection to this host/port is permitted. */ | |
2320 | if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION) | |
2321 | fatal("channel_request_remote_forwarding: too many forwards"); | |
2322 | ||
2323 | /* Send the forward request to the remote side. */ | |
2324 | if (compat20) { | |
2325 | const char *address_to_bind = "0.0.0.0"; | |
2326 | packet_start(SSH2_MSG_GLOBAL_REQUEST); | |
2327 | packet_put_cstring("tcpip-forward"); | |
2328 | packet_put_char(1); /* boolean: want reply */ | |
2329 | packet_put_cstring(address_to_bind); | |
2330 | packet_put_int(listen_port); | |
2331 | packet_send(); | |
2332 | packet_write_wait(); | |
2333 | /* Assume that server accepts the request */ | |
2334 | success = 1; | |
2335 | } else { | |
2336 | packet_start(SSH_CMSG_PORT_FORWARD_REQUEST); | |
2337 | packet_put_int(listen_port); | |
2338 | packet_put_cstring(host_to_connect); | |
2339 | packet_put_int(port_to_connect); | |
2340 | packet_send(); | |
2341 | packet_write_wait(); | |
2342 | ||
2343 | /* Wait for response from the remote side. */ | |
2344 | type = packet_read(); | |
2345 | switch (type) { | |
2346 | case SSH_SMSG_SUCCESS: | |
2347 | success = 1; | |
2348 | break; | |
2349 | case SSH_SMSG_FAILURE: | |
2350 | logit("Warning: Server denied remote port forwarding."); | |
2351 | break; | |
2352 | default: | |
2353 | /* Unknown packet */ | |
2354 | packet_disconnect("Protocol error for port forward request:" | |
2355 | "received packet type %d.", type); | |
2356 | } | |
2357 | } | |
2358 | if (success) { | |
2359 | permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect); | |
2360 | permitted_opens[num_permitted_opens].port_to_connect = port_to_connect; | |
2361 | permitted_opens[num_permitted_opens].listen_port = listen_port; | |
2362 | num_permitted_opens++; | |
2363 | } | |
2364 | } | |
2365 | ||
2366 | /* | |
2367 | * Request cancellation of remote forwarding of connection host:port from | |
2368 | * local side. | |
2369 | */ | |
2370 | ||
2371 | void | |
2372 | channel_request_rforward_cancel(u_short port) | |
2373 | { | |
2374 | int i; | |
2375 | const char *address_to_bind = "0.0.0.0"; | |
2376 | ||
2377 | if (!compat20) | |
2378 | return; | |
2379 | ||
2380 | for (i = 0; i < num_permitted_opens; i++) { | |
2381 | if (permitted_opens[i].host_to_connect != NULL && | |
2382 | permitted_opens[i].listen_port == port) | |
2383 | break; | |
2384 | } | |
2385 | if (i >= num_permitted_opens) { | |
2386 | debug("%s: requested forward not found", __func__); | |
2387 | return; | |
2388 | } | |
2389 | packet_start(SSH2_MSG_GLOBAL_REQUEST); | |
2390 | packet_put_cstring("cancel-tcpip-forward"); | |
2391 | packet_put_char(0); | |
2392 | packet_put_cstring(address_to_bind); | |
2393 | packet_put_int(port); | |
2394 | packet_send(); | |
2395 | ||
2396 | permitted_opens[i].listen_port = 0; | |
2397 | permitted_opens[i].port_to_connect = 0; | |
2398 | free(permitted_opens[i].host_to_connect); | |
2399 | permitted_opens[i].host_to_connect = NULL; | |
2400 | } | |
2401 | ||
2402 | /* | |
2403 | * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates | |
2404 | * listening for the port, and sends back a success reply (or disconnect | |
2405 | * message if there was an error). This never returns if there was an error. | |
2406 | */ | |
2407 | ||
2408 | void | |
2409 | channel_input_port_forward_request(int is_root, int gateway_ports) | |
2410 | { | |
2411 | u_short port, host_port; | |
2412 | char *hostname; | |
2413 | ||
2414 | /* Get arguments from the packet. */ | |
2415 | port = packet_get_int(); | |
2416 | hostname = packet_get_string(NULL); | |
2417 | host_port = packet_get_int(); | |
2418 | ||
2419 | #ifndef HAVE_CYGWIN | |
2420 | /* | |
2421 | * Check that an unprivileged user is not trying to forward a | |
2422 | * privileged port. | |
2423 | */ | |
2424 | if (port < IPPORT_RESERVED && !is_root) | |
2425 | packet_disconnect( | |
2426 | "Requested forwarding of port %d but user is not root.", | |
2427 | port); | |
2428 | if (host_port == 0) | |
2429 | packet_disconnect("Dynamic forwarding denied."); | |
2430 | #endif | |
2431 | ||
2432 | /* Initiate forwarding */ | |
2433 | channel_setup_local_fwd_listener(port, hostname, host_port, gateway_ports); | |
2434 | ||
2435 | /* Free the argument string. */ | |
2436 | xfree(hostname); | |
2437 | } | |
2438 | ||
2439 | /* | |
2440 | * Permits opening to any host/port if permitted_opens[] is empty. This is | |
2441 | * usually called by the server, because the user could connect to any port | |
2442 | * anyway, and the server has no way to know but to trust the client anyway. | |
2443 | */ | |
2444 | void | |
2445 | channel_permit_all_opens(void) | |
2446 | { | |
2447 | if (num_permitted_opens == 0) | |
2448 | all_opens_permitted = 1; | |
2449 | } | |
2450 | ||
2451 | void | |
2452 | channel_add_permitted_opens(char *host, int port) | |
2453 | { | |
2454 | if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION) | |
2455 | fatal("channel_request_remote_forwarding: too many forwards"); | |
2456 | debug("allow port forwarding to host %s port %d", host, port); | |
2457 | ||
2458 | permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host); | |
2459 | permitted_opens[num_permitted_opens].port_to_connect = port; | |
2460 | num_permitted_opens++; | |
2461 | ||
2462 | all_opens_permitted = 0; | |
2463 | } | |
2464 | ||
2465 | void | |
2466 | channel_clear_permitted_opens(void) | |
2467 | { | |
2468 | int i; | |
2469 | ||
2470 | for (i = 0; i < num_permitted_opens; i++) | |
2471 | if (permitted_opens[i].host_to_connect != NULL) | |
2472 | xfree(permitted_opens[i].host_to_connect); | |
2473 | num_permitted_opens = 0; | |
2474 | ||
2475 | } | |
2476 | ||
2477 | ||
2478 | /* return socket to remote host, port */ | |
2479 | static int | |
2480 | connect_to(const char *host, u_short port) | |
2481 | { | |
2482 | struct addrinfo hints, *ai, *aitop; | |
2483 | char ntop[NI_MAXHOST], strport[NI_MAXSERV]; | |
2484 | int gaierr; | |
2485 | int sock = -1; | |
2486 | ||
2487 | memset(&hints, 0, sizeof(hints)); | |
2488 | hints.ai_family = IPv4or6; | |
2489 | hints.ai_socktype = SOCK_STREAM; | |
2490 | snprintf(strport, sizeof strport, "%d", port); | |
2491 | if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) { | |
2492 | error("connect_to %.100s: unknown host (%s)", host, | |
2493 | gai_strerror(gaierr)); | |
2494 | return -1; | |
2495 | } | |
2496 | for (ai = aitop; ai; ai = ai->ai_next) { | |
2497 | if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) | |
2498 | continue; | |
2499 | if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), | |
2500 | strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) { | |
2501 | error("connect_to: getnameinfo failed"); | |
2502 | continue; | |
2503 | } | |
2504 | sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); | |
2505 | if (sock < 0) { | |
2506 | if (ai->ai_next == NULL) | |
2507 | error("socket: %.100s", strerror(errno)); | |
2508 | else | |
2509 | verbose("socket: %.100s", strerror(errno)); | |
2510 | continue; | |
2511 | } | |
2512 | if (set_nonblock(sock) == -1) | |
2513 | fatal("%s: set_nonblock(%d)", __func__, sock); | |
2514 | if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 && | |
2515 | errno != EINPROGRESS) { | |
2516 | error("connect_to %.100s port %s: %.100s", ntop, strport, | |
2517 | strerror(errno)); | |
2518 | close(sock); | |
2519 | continue; /* fail -- try next */ | |
2520 | } | |
2521 | break; /* success */ | |
2522 | ||
2523 | } | |
2524 | freeaddrinfo(aitop); | |
2525 | if (!ai) { | |
2526 | error("connect_to %.100s port %d: failed.", host, port); | |
2527 | return -1; | |
2528 | } | |
2529 | /* success */ | |
2530 | set_nodelay(sock); | |
2531 | return sock; | |
2532 | } | |
2533 | ||
2534 | int | |
2535 | channel_connect_by_listen_address(u_short listen_port) | |
2536 | { | |
2537 | int i; | |
2538 | ||
2539 | for (i = 0; i < num_permitted_opens; i++) | |
2540 | if (permitted_opens[i].host_to_connect != NULL && | |
2541 | permitted_opens[i].listen_port == listen_port) | |
2542 | return connect_to( | |
2543 | permitted_opens[i].host_to_connect, | |
2544 | permitted_opens[i].port_to_connect); | |
2545 | error("WARNING: Server requests forwarding for unknown listen_port %d", | |
2546 | listen_port); | |
2547 | return -1; | |
2548 | } | |
2549 | ||
2550 | /* Check if connecting to that port is permitted and connect. */ | |
2551 | int | |
2552 | channel_connect_to(const char *host, u_short port) | |
2553 | { | |
2554 | int i, permit; | |
2555 | ||
2556 | permit = all_opens_permitted; | |
2557 | if (!permit) { | |
2558 | for (i = 0; i < num_permitted_opens; i++) | |
2559 | if (permitted_opens[i].host_to_connect != NULL && | |
2560 | permitted_opens[i].port_to_connect == port && | |
2561 | strcmp(permitted_opens[i].host_to_connect, host) == 0) | |
2562 | permit = 1; | |
2563 | ||
2564 | } | |
2565 | if (!permit) { | |
2566 | logit("Received request to connect to host %.100s port %d, " | |
2567 | "but the request was denied.", host, port); | |
2568 | return -1; | |
2569 | } | |
2570 | return connect_to(host, port); | |
2571 | } | |
2572 | ||
2573 | void | |
2574 | channel_send_window_changes(void) | |
2575 | { | |
2576 | int i; | |
2577 | struct winsize ws; | |
2578 | ||
2579 | for (i = 0; i < channels_alloc; i++) { | |
2580 | if (channels[i] == NULL || | |
2581 | channels[i]->type != SSH_CHANNEL_OPEN) | |
2582 | continue; | |
2583 | if (ioctl(channels[i]->rfd, TIOCGWINSZ, &ws) < 0) | |
2584 | continue; | |
2585 | channel_request_start(i, "window-change", 0); | |
2586 | packet_put_int(ws.ws_col); | |
2587 | packet_put_int(ws.ws_row); | |
2588 | packet_put_int(ws.ws_xpixel); | |
2589 | packet_put_int(ws.ws_ypixel); | |
2590 | packet_send(); | |
2591 | } | |
2592 | } | |
2593 | ||
2594 | /* -- X11 forwarding */ | |
2595 | ||
2596 | /* | |
2597 | * Creates an internet domain socket for listening for X11 connections. | |
2598 | * Returns 0 and a suitable display number for the DISPLAY variable | |
2599 | * stored in display_numberp , or -1 if an error occurs. | |
2600 | */ | |
2601 | int | |
2602 | x11_create_display_inet(int x11_display_offset, int x11_use_localhost, | |
2603 | int single_connection, u_int *display_numberp) | |
2604 | { | |
2605 | Channel *nc = NULL; | |
2606 | int display_number, sock; | |
2607 | u_short port; | |
2608 | struct addrinfo hints, *ai, *aitop; | |
2609 | char strport[NI_MAXSERV]; | |
2610 | int gaierr, n, num_socks = 0, socks[NUM_SOCKS]; | |
2611 | ||
2612 | for (display_number = x11_display_offset; | |
2613 | display_number < MAX_DISPLAYS; | |
2614 | display_number++) { | |
2615 | port = 6000 + display_number; | |
2616 | memset(&hints, 0, sizeof(hints)); | |
2617 | hints.ai_family = IPv4or6; | |
2618 | hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE; | |
2619 | hints.ai_socktype = SOCK_STREAM; | |
2620 | snprintf(strport, sizeof strport, "%d", port); | |
2621 | if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) { | |
2622 | error("getaddrinfo: %.100s", gai_strerror(gaierr)); | |
2623 | return -1; | |
2624 | } | |
2625 | for (ai = aitop; ai; ai = ai->ai_next) { | |
2626 | if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) | |
2627 | continue; | |
2628 | sock = socket(ai->ai_family, ai->ai_socktype, | |
2629 | ai->ai_protocol); | |
2630 | if (sock < 0) { | |
2631 | if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) { | |
2632 | error("socket: %.100s", strerror(errno)); | |
2633 | freeaddrinfo(aitop); | |
2634 | return -1; | |
2635 | } else { | |
2636 | debug("x11_create_display_inet: Socket family %d not supported", | |
2637 | ai->ai_family); | |
2638 | continue; | |
2639 | } | |
2640 | } | |
2641 | #ifdef IPV6_V6ONLY | |
2642 | if (ai->ai_family == AF_INET6) { | |
2643 | int on = 1; | |
2644 | if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) < 0) | |
2645 | error("setsockopt IPV6_V6ONLY: %.100s", strerror(errno)); | |
2646 | } | |
2647 | #endif | |
2648 | if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) { | |
2649 | debug2("bind port %d: %.100s", port, strerror(errno)); | |
2650 | close(sock); | |
2651 | ||
2652 | if (ai->ai_next) | |
2653 | continue; | |
2654 | ||
2655 | for (n = 0; n < num_socks; n++) { | |
2656 | close(socks[n]); | |
2657 | } | |
2658 | num_socks = 0; | |
2659 | break; | |
2660 | } | |
2661 | socks[num_socks++] = sock; | |
2662 | #ifndef DONT_TRY_OTHER_AF | |
2663 | if (num_socks == NUM_SOCKS) | |
2664 | break; | |
2665 | #else | |
2666 | if (x11_use_localhost) { | |
2667 | if (num_socks == NUM_SOCKS) | |
2668 | break; | |
2669 | } else { | |
2670 | break; | |
2671 | } | |
2672 | #endif | |
2673 | } | |
2674 | freeaddrinfo(aitop); | |
2675 | if (num_socks > 0) | |
2676 | break; | |
2677 | } | |
2678 | if (display_number >= MAX_DISPLAYS) { | |
2679 | error("Failed to allocate internet-domain X11 display socket."); | |
2680 | return -1; | |
2681 | } | |
2682 | /* Start listening for connections on the socket. */ | |
2683 | for (n = 0; n < num_socks; n++) { | |
2684 | sock = socks[n]; | |
2685 | if (listen(sock, SSH_LISTEN_BACKLOG) < 0) { | |
2686 | error("listen: %.100s", strerror(errno)); | |
2687 | close(sock); | |
2688 | return -1; | |
2689 | } | |
2690 | } | |
2691 | ||
2692 | /* Allocate a channel for each socket. */ | |
2693 | for (n = 0; n < num_socks; n++) { | |
2694 | sock = socks[n]; | |
2695 | nc = channel_new("x11 listener", | |
2696 | SSH_CHANNEL_X11_LISTENER, sock, sock, -1, | |
2697 | CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, | |
2698 | 0, "X11 inet listener", 1); | |
2699 | nc->single_connection = single_connection; | |
2700 | } | |
2701 | ||
2702 | /* Return the display number for the DISPLAY environment variable. */ | |
2703 | *display_numberp = display_number; | |
2704 | return (0); | |
2705 | } | |
2706 | ||
2707 | static int | |
2708 | connect_local_xsocket(u_int dnr) | |
2709 | { | |
2710 | int sock; | |
2711 | struct sockaddr_un addr; | |
2712 | ||
2713 | sock = socket(AF_UNIX, SOCK_STREAM, 0); | |
2714 | if (sock < 0) | |
2715 | error("socket: %.100s", strerror(errno)); | |
2716 | memset(&addr, 0, sizeof(addr)); | |
2717 | addr.sun_family = AF_UNIX; | |
2718 | snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr); | |
2719 | if (connect(sock, (struct sockaddr *) & addr, sizeof(addr)) == 0) | |
2720 | return sock; | |
2721 | close(sock); | |
2722 | error("connect %.100s: %.100s", addr.sun_path, strerror(errno)); | |
2723 | return -1; | |
2724 | } | |
2725 | ||
2726 | int | |
2727 | x11_connect_display(void) | |
2728 | { | |
2729 | int display_number, sock = 0; | |
2730 | const char *display; | |
2731 | char buf[1024], *cp; | |
2732 | struct addrinfo hints, *ai, *aitop; | |
2733 | char strport[NI_MAXSERV]; | |
2734 | int gaierr; | |
2735 | ||
2736 | /* Try to open a socket for the local X server. */ | |
2737 | display = getenv("DISPLAY"); | |
2738 | if (!display) { | |
2739 | error("DISPLAY not set."); | |
2740 | return -1; | |
2741 | } | |
2742 | /* | |
2743 | * Now we decode the value of the DISPLAY variable and make a | |
2744 | * connection to the real X server. | |
2745 | */ | |
2746 | ||
2747 | /* | |
2748 | * Check if it is a unix domain socket. Unix domain displays are in | |
2749 | * one of the following formats: unix:d[.s], :d[.s], ::d[.s] | |
2750 | */ | |
2751 | if (strncmp(display, "unix:", 5) == 0 || | |
2752 | display[0] == ':') { | |
2753 | /* Connect to the unix domain socket. */ | |
2754 | if (sscanf(strrchr(display, ':') + 1, "%d", &display_number) != 1) { | |
2755 | error("Could not parse display number from DISPLAY: %.100s", | |
2756 | display); | |
2757 | return -1; | |
2758 | } | |
2759 | /* Create a socket. */ | |
2760 | sock = connect_local_xsocket(display_number); | |
2761 | if (sock < 0) | |
2762 | return -1; | |
2763 | ||
2764 | /* OK, we now have a connection to the display. */ | |
2765 | return sock; | |
2766 | } | |
2767 | /* | |
2768 | * Connect to an inet socket. The DISPLAY value is supposedly | |
2769 | * hostname:d[.s], where hostname may also be numeric IP address. | |
2770 | */ | |
2771 | strlcpy(buf, display, sizeof(buf)); | |
2772 | cp = strchr(buf, ':'); | |
2773 | if (!cp) { | |
2774 | error("Could not find ':' in DISPLAY: %.100s", display); | |
2775 | return -1; | |
2776 | } | |
2777 | *cp = 0; | |
2778 | /* buf now contains the host name. But first we parse the display number. */ | |
2779 | if (sscanf(cp + 1, "%d", &display_number) != 1) { | |
2780 | error("Could not parse display number from DISPLAY: %.100s", | |
2781 | display); | |
2782 | return -1; | |
2783 | } | |
2784 | ||
2785 | /* Look up the host address */ | |
2786 | memset(&hints, 0, sizeof(hints)); | |
2787 | hints.ai_family = IPv4or6; | |
2788 | hints.ai_socktype = SOCK_STREAM; | |
2789 | snprintf(strport, sizeof strport, "%d", 6000 + display_number); | |
2790 | if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) { | |
2791 | error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr)); | |
2792 | return -1; | |
2793 | } | |
2794 | for (ai = aitop; ai; ai = ai->ai_next) { | |
2795 | /* Create a socket. */ | |
2796 | sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); | |
2797 | if (sock < 0) { | |
2798 | debug2("socket: %.100s", strerror(errno)); | |
2799 | continue; | |
2800 | } | |
2801 | /* Connect it to the display. */ | |
2802 | if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) { | |
2803 | debug2("connect %.100s port %d: %.100s", buf, | |
2804 | 6000 + display_number, strerror(errno)); | |
2805 | close(sock); | |
2806 | continue; | |
2807 | } | |
2808 | /* Success */ | |
2809 | break; | |
2810 | } | |
2811 | freeaddrinfo(aitop); | |
2812 | if (!ai) { | |
2813 | error("connect %.100s port %d: %.100s", buf, 6000 + display_number, | |
2814 | strerror(errno)); | |
2815 | return -1; | |
2816 | } | |
2817 | set_nodelay(sock); | |
2818 | return sock; | |
2819 | } | |
2820 | ||
2821 | /* | |
2822 | * This is called when SSH_SMSG_X11_OPEN is received. The packet contains | |
2823 | * the remote channel number. We should do whatever we want, and respond | |
2824 | * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE. | |
2825 | */ | |
2826 | ||
2827 | void | |
2828 | x11_input_open(int type, u_int32_t seq, void *ctxt) | |
2829 | { | |
2830 | Channel *c = NULL; | |
2831 | int remote_id, sock = 0; | |
2832 | char *remote_host; | |
2833 | ||
2834 | debug("Received X11 open request."); | |
2835 | ||
2836 | remote_id = packet_get_int(); | |
2837 | ||
2838 | if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) { | |
2839 | remote_host = packet_get_string(NULL); | |
2840 | } else { | |
2841 | remote_host = xstrdup("unknown (remote did not supply name)"); | |
2842 | } | |
2843 | packet_check_eom(); | |
2844 | ||
2845 | /* Obtain a connection to the real X display. */ | |
2846 | sock = x11_connect_display(); | |
2847 | if (sock != -1) { | |
2848 | /* Allocate a channel for this connection. */ | |
2849 | c = channel_new("connected x11 socket", | |
2850 | SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0, | |
2851 | remote_host, 1); | |
2852 | c->remote_id = remote_id; | |
2853 | c->force_drain = 1; | |
2854 | } | |
2855 | xfree(remote_host); | |
2856 | if (c == NULL) { | |
2857 | /* Send refusal to the remote host. */ | |
2858 | packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); | |
2859 | packet_put_int(remote_id); | |
2860 | } else { | |
2861 | /* Send a confirmation to the remote host. */ | |
2862 | packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION); | |
2863 | packet_put_int(remote_id); | |
2864 | packet_put_int(c->self); | |
2865 | } | |
2866 | packet_send(); | |
2867 | } | |
2868 | ||
2869 | /* dummy protocol handler that denies SSH-1 requests (agent/x11) */ | |
2870 | void | |
2871 | deny_input_open(int type, u_int32_t seq, void *ctxt) | |
2872 | { | |
2873 | int rchan = packet_get_int(); | |
2874 | ||
2875 | switch (type) { | |
2876 | case SSH_SMSG_AGENT_OPEN: | |
2877 | error("Warning: ssh server tried agent forwarding."); | |
2878 | break; | |
2879 | case SSH_SMSG_X11_OPEN: | |
2880 | error("Warning: ssh server tried X11 forwarding."); | |
2881 | break; | |
2882 | default: | |
2883 | error("deny_input_open: type %d", type); | |
2884 | break; | |
2885 | } | |
2886 | error("Warning: this is probably a break in attempt by a malicious server."); | |
2887 | packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); | |
2888 | packet_put_int(rchan); | |
2889 | packet_send(); | |
2890 | } | |
2891 | ||
2892 | /* | |
2893 | * Requests forwarding of X11 connections, generates fake authentication | |
2894 | * data, and enables authentication spoofing. | |
2895 | * This should be called in the client only. | |
2896 | */ | |
2897 | void | |
2898 | x11_request_forwarding_with_spoofing(int client_session_id, | |
2899 | const char *proto, const char *data) | |
2900 | { | |
2901 | u_int data_len = (u_int) strlen(data) / 2; | |
2902 | u_int i, value, len; | |
2903 | char *new_data; | |
2904 | int screen_number; | |
2905 | const char *cp; | |
2906 | u_int32_t rand = 0; | |
2907 | ||
2908 | cp = getenv("DISPLAY"); | |
2909 | if (cp) | |
2910 | cp = strchr(cp, ':'); | |
2911 | if (cp) | |
2912 | cp = strchr(cp, '.'); | |
2913 | if (cp) | |
2914 | screen_number = atoi(cp + 1); | |
2915 | else | |
2916 | screen_number = 0; | |
2917 | ||
2918 | /* Save protocol name. */ | |
2919 | x11_saved_proto = xstrdup(proto); | |
2920 | ||
2921 | /* | |
2922 | * Extract real authentication data and generate fake data of the | |
2923 | * same length. | |
2924 | */ | |
2925 | x11_saved_data = xmalloc(data_len); | |
2926 | x11_fake_data = xmalloc(data_len); | |
2927 | for (i = 0; i < data_len; i++) { | |
2928 | if (sscanf(data + 2 * i, "%2x", &value) != 1) | |
2929 | fatal("x11_request_forwarding: bad authentication data: %.100s", data); | |
2930 | if (i % 4 == 0) | |
2931 | rand = arc4random(); | |
2932 | x11_saved_data[i] = value; | |
2933 | x11_fake_data[i] = rand & 0xff; | |
2934 | rand >>= 8; | |
2935 | } | |
2936 | x11_saved_data_len = data_len; | |
2937 | x11_fake_data_len = data_len; | |
2938 | ||
2939 | /* Convert the fake data into hex. */ | |
2940 | len = 2 * data_len + 1; | |
2941 | new_data = xmalloc(len); | |
2942 | for (i = 0; i < data_len; i++) | |
2943 | snprintf(new_data + 2 * i, len - 2 * i, | |
2944 | "%02x", (u_char) x11_fake_data[i]); | |
2945 | ||
2946 | /* Send the request packet. */ | |
2947 | if (compat20) { | |
2948 | channel_request_start(client_session_id, "x11-req", 0); | |
2949 | packet_put_char(0); /* XXX bool single connection */ | |
2950 | } else { | |
2951 | packet_start(SSH_CMSG_X11_REQUEST_FORWARDING); | |
2952 | } | |
2953 | packet_put_cstring(proto); | |
2954 | packet_put_cstring(new_data); | |
2955 | packet_put_int(screen_number); | |
2956 | packet_send(); | |
2957 | packet_write_wait(); | |
2958 | xfree(new_data); | |
2959 | } | |
2960 | ||
2961 | ||
2962 | /* -- agent forwarding */ | |
2963 | ||
2964 | /* Sends a message to the server to request authentication fd forwarding. */ | |
2965 | ||
2966 | void | |
2967 | auth_request_forwarding(void) | |
2968 | { | |
2969 | packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING); | |
2970 | packet_send(); | |
2971 | packet_write_wait(); | |
2972 | } |