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1 | /* $OpenBSD: channels.c,v 1.257 2006/07/17 12:06:00 dtucker Exp $ */ | |
2 | /* | |
3 | * Author: Tatu Ylonen <ylo@cs.hut.fi> | |
4 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland | |
5 | * All rights reserved | |
6 | * This file contains functions for generic socket connection forwarding. | |
7 | * There is also code for initiating connection forwarding for X11 connections, | |
8 | * arbitrary tcp/ip connections, and the authentication agent connection. | |
9 | * | |
10 | * As far as I am concerned, the code I have written for this software | |
11 | * can be used freely for any purpose. Any derived versions of this | |
12 | * software must be clearly marked as such, and if the derived work is | |
13 | * incompatible with the protocol description in the RFC file, it must be | |
14 | * called by a name other than "ssh" or "Secure Shell". | |
15 | * | |
16 | * SSH2 support added by Markus Friedl. | |
17 | * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved. | |
18 | * Copyright (c) 1999 Dug Song. All rights reserved. | |
19 | * Copyright (c) 1999 Theo de Raadt. All rights reserved. | |
20 | * | |
21 | * Redistribution and use in source and binary forms, with or without | |
22 | * modification, are permitted provided that the following conditions | |
23 | * are met: | |
24 | * 1. Redistributions of source code must retain the above copyright | |
25 | * notice, this list of conditions and the following disclaimer. | |
26 | * 2. Redistributions in binary form must reproduce the above copyright | |
27 | * notice, this list of conditions and the following disclaimer in the | |
28 | * documentation and/or other materials provided with the distribution. | |
29 | * | |
30 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR | |
31 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES | |
32 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. | |
33 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, | |
34 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | |
35 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
36 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
37 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
38 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF | |
39 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
40 | */ | |
41 | ||
42 | #include "includes.h" | |
43 | ||
44 | #include <sys/ioctl.h> | |
45 | #include <sys/types.h> | |
46 | #include <sys/un.h> | |
47 | #include <sys/socket.h> | |
48 | ||
49 | #include <netinet/in.h> | |
50 | #include <arpa/inet.h> | |
51 | ||
52 | #include <errno.h> | |
53 | #if defined(HAVE_NETDB_H) | |
54 | # include <netdb.h> | |
55 | #endif | |
56 | #include <termios.h> | |
57 | #include <unistd.h> | |
58 | ||
59 | #include "ssh.h" | |
60 | #include "ssh1.h" | |
61 | #include "ssh2.h" | |
62 | #include "packet.h" | |
63 | #include "xmalloc.h" | |
64 | #include "log.h" | |
65 | #include "misc.h" | |
66 | #include "channels.h" | |
67 | #include "compat.h" | |
68 | #include "canohost.h" | |
69 | #include "key.h" | |
70 | #include "authfd.h" | |
71 | #include "pathnames.h" | |
72 | #include "bufaux.h" | |
73 | ||
74 | /* -- channel core */ | |
75 | ||
76 | /* | |
77 | * Pointer to an array containing all allocated channels. The array is | |
78 | * dynamically extended as needed. | |
79 | */ | |
80 | static Channel **channels = NULL; | |
81 | ||
82 | /* | |
83 | * Size of the channel array. All slots of the array must always be | |
84 | * initialized (at least the type field); unused slots set to NULL | |
85 | */ | |
86 | static u_int channels_alloc = 0; | |
87 | ||
88 | /* | |
89 | * Maximum file descriptor value used in any of the channels. This is | |
90 | * updated in channel_new. | |
91 | */ | |
92 | static int channel_max_fd = 0; | |
93 | ||
94 | ||
95 | /* -- tcp forwarding */ | |
96 | ||
97 | /* | |
98 | * Data structure for storing which hosts are permitted for forward requests. | |
99 | * The local sides of any remote forwards are stored in this array to prevent | |
100 | * a corrupt remote server from accessing arbitrary TCP/IP ports on our local | |
101 | * network (which might be behind a firewall). | |
102 | */ | |
103 | typedef struct { | |
104 | char *host_to_connect; /* Connect to 'host'. */ | |
105 | u_short port_to_connect; /* Connect to 'port'. */ | |
106 | u_short listen_port; /* Remote side should listen port number. */ | |
107 | } ForwardPermission; | |
108 | ||
109 | /* List of all permitted host/port pairs to connect by the user. */ | |
110 | static ForwardPermission permitted_opens[SSH_MAX_FORWARDS_PER_DIRECTION]; | |
111 | ||
112 | /* List of all permitted host/port pairs to connect by the admin. */ | |
113 | static ForwardPermission permitted_adm_opens[SSH_MAX_FORWARDS_PER_DIRECTION]; | |
114 | ||
115 | /* Number of permitted host/port pairs in the array permitted by the user. */ | |
116 | static int num_permitted_opens = 0; | |
117 | ||
118 | /* Number of permitted host/port pair in the array permitted by the admin. */ | |
119 | static int num_adm_permitted_opens = 0; | |
120 | ||
121 | /* | |
122 | * If this is true, all opens are permitted. This is the case on the server | |
123 | * on which we have to trust the client anyway, and the user could do | |
124 | * anything after logging in anyway. | |
125 | */ | |
126 | static int all_opens_permitted = 0; | |
127 | ||
128 | ||
129 | /* -- X11 forwarding */ | |
130 | ||
131 | /* Maximum number of fake X11 displays to try. */ | |
132 | #define MAX_DISPLAYS 1000 | |
133 | ||
134 | /* Saved X11 local (client) display. */ | |
135 | static char *x11_saved_display = NULL; | |
136 | ||
137 | /* Saved X11 authentication protocol name. */ | |
138 | static char *x11_saved_proto = NULL; | |
139 | ||
140 | /* Saved X11 authentication data. This is the real data. */ | |
141 | static char *x11_saved_data = NULL; | |
142 | static u_int x11_saved_data_len = 0; | |
143 | ||
144 | /* | |
145 | * Fake X11 authentication data. This is what the server will be sending us; | |
146 | * we should replace any occurrences of this by the real data. | |
147 | */ | |
148 | static u_char *x11_fake_data = NULL; | |
149 | static u_int x11_fake_data_len; | |
150 | ||
151 | ||
152 | /* -- agent forwarding */ | |
153 | ||
154 | #define NUM_SOCKS 10 | |
155 | ||
156 | /* AF_UNSPEC or AF_INET or AF_INET6 */ | |
157 | static int IPv4or6 = AF_UNSPEC; | |
158 | ||
159 | /* helper */ | |
160 | static void port_open_helper(Channel *c, char *rtype); | |
161 | ||
162 | /* -- channel core */ | |
163 | ||
164 | Channel * | |
165 | channel_by_id(int id) | |
166 | { | |
167 | Channel *c; | |
168 | ||
169 | if (id < 0 || (u_int)id >= channels_alloc) { | |
170 | logit("channel_by_id: %d: bad id", id); | |
171 | return NULL; | |
172 | } | |
173 | c = channels[id]; | |
174 | if (c == NULL) { | |
175 | logit("channel_by_id: %d: bad id: channel free", id); | |
176 | return NULL; | |
177 | } | |
178 | return c; | |
179 | } | |
180 | ||
181 | /* | |
182 | * Returns the channel if it is allowed to receive protocol messages. | |
183 | * Private channels, like listening sockets, may not receive messages. | |
184 | */ | |
185 | Channel * | |
186 | channel_lookup(int id) | |
187 | { | |
188 | Channel *c; | |
189 | ||
190 | if ((c = channel_by_id(id)) == NULL) | |
191 | return (NULL); | |
192 | ||
193 | switch (c->type) { | |
194 | case SSH_CHANNEL_X11_OPEN: | |
195 | case SSH_CHANNEL_LARVAL: | |
196 | case SSH_CHANNEL_CONNECTING: | |
197 | case SSH_CHANNEL_DYNAMIC: | |
198 | case SSH_CHANNEL_OPENING: | |
199 | case SSH_CHANNEL_OPEN: | |
200 | case SSH_CHANNEL_INPUT_DRAINING: | |
201 | case SSH_CHANNEL_OUTPUT_DRAINING: | |
202 | return (c); | |
203 | } | |
204 | logit("Non-public channel %d, type %d.", id, c->type); | |
205 | return (NULL); | |
206 | } | |
207 | ||
208 | /* | |
209 | * Register filedescriptors for a channel, used when allocating a channel or | |
210 | * when the channel consumer/producer is ready, e.g. shell exec'd | |
211 | */ | |
212 | static void | |
213 | channel_register_fds(Channel *c, int rfd, int wfd, int efd, | |
214 | int extusage, int nonblock) | |
215 | { | |
216 | /* Update the maximum file descriptor value. */ | |
217 | channel_max_fd = MAX(channel_max_fd, rfd); | |
218 | channel_max_fd = MAX(channel_max_fd, wfd); | |
219 | channel_max_fd = MAX(channel_max_fd, efd); | |
220 | ||
221 | /* XXX set close-on-exec -markus */ | |
222 | ||
223 | c->rfd = rfd; | |
224 | c->wfd = wfd; | |
225 | c->sock = (rfd == wfd) ? rfd : -1; | |
226 | c->ctl_fd = -1; /* XXX: set elsewhere */ | |
227 | c->efd = efd; | |
228 | c->extended_usage = extusage; | |
229 | ||
230 | /* XXX ugly hack: nonblock is only set by the server */ | |
231 | if (nonblock && isatty(c->rfd)) { | |
232 | debug2("channel %d: rfd %d isatty", c->self, c->rfd); | |
233 | c->isatty = 1; | |
234 | if (!isatty(c->wfd)) { | |
235 | error("channel %d: wfd %d is not a tty?", | |
236 | c->self, c->wfd); | |
237 | } | |
238 | } else { | |
239 | c->isatty = 0; | |
240 | } | |
241 | c->wfd_isatty = isatty(c->wfd); | |
242 | ||
243 | /* enable nonblocking mode */ | |
244 | if (nonblock) { | |
245 | if (rfd != -1) | |
246 | set_nonblock(rfd); | |
247 | if (wfd != -1) | |
248 | set_nonblock(wfd); | |
249 | if (efd != -1) | |
250 | set_nonblock(efd); | |
251 | } | |
252 | } | |
253 | ||
254 | /* | |
255 | * Allocate a new channel object and set its type and socket. This will cause | |
256 | * remote_name to be freed. | |
257 | */ | |
258 | Channel * | |
259 | channel_new(char *ctype, int type, int rfd, int wfd, int efd, | |
260 | u_int window, u_int maxpack, int extusage, char *remote_name, int nonblock) | |
261 | { | |
262 | int found; | |
263 | u_int i; | |
264 | Channel *c; | |
265 | ||
266 | /* Do initial allocation if this is the first call. */ | |
267 | if (channels_alloc == 0) { | |
268 | channels_alloc = 10; | |
269 | channels = xcalloc(channels_alloc, sizeof(Channel *)); | |
270 | for (i = 0; i < channels_alloc; i++) | |
271 | channels[i] = NULL; | |
272 | } | |
273 | /* Try to find a free slot where to put the new channel. */ | |
274 | for (found = -1, i = 0; i < channels_alloc; i++) | |
275 | if (channels[i] == NULL) { | |
276 | /* Found a free slot. */ | |
277 | found = (int)i; | |
278 | break; | |
279 | } | |
280 | if (found < 0) { | |
281 | /* There are no free slots. Take last+1 slot and expand the array. */ | |
282 | found = channels_alloc; | |
283 | if (channels_alloc > 10000) | |
284 | fatal("channel_new: internal error: channels_alloc %d " | |
285 | "too big.", channels_alloc); | |
286 | channels = xrealloc(channels, channels_alloc + 10, | |
287 | sizeof(Channel *)); | |
288 | channels_alloc += 10; | |
289 | debug2("channel: expanding %d", channels_alloc); | |
290 | for (i = found; i < channels_alloc; i++) | |
291 | channels[i] = NULL; | |
292 | } | |
293 | /* Initialize and return new channel. */ | |
294 | c = channels[found] = xcalloc(1, sizeof(Channel)); | |
295 | buffer_init(&c->input); | |
296 | buffer_init(&c->output); | |
297 | buffer_init(&c->extended); | |
298 | c->ostate = CHAN_OUTPUT_OPEN; | |
299 | c->istate = CHAN_INPUT_OPEN; | |
300 | c->flags = 0; | |
301 | channel_register_fds(c, rfd, wfd, efd, extusage, nonblock); | |
302 | c->self = found; | |
303 | c->type = type; | |
304 | c->ctype = ctype; | |
305 | c->local_window = window; | |
306 | c->local_window_max = window; | |
307 | c->local_consumed = 0; | |
308 | c->local_maxpacket = maxpack; | |
309 | c->remote_id = -1; | |
310 | c->remote_name = xstrdup(remote_name); | |
311 | c->remote_window = 0; | |
312 | c->remote_maxpacket = 0; | |
313 | c->force_drain = 0; | |
314 | c->single_connection = 0; | |
315 | c->detach_user = NULL; | |
316 | c->detach_close = 0; | |
317 | c->confirm = NULL; | |
318 | c->confirm_ctx = NULL; | |
319 | c->input_filter = NULL; | |
320 | c->output_filter = NULL; | |
321 | debug("channel %d: new [%s]", found, remote_name); | |
322 | return c; | |
323 | } | |
324 | ||
325 | static int | |
326 | channel_find_maxfd(void) | |
327 | { | |
328 | u_int i; | |
329 | int max = 0; | |
330 | Channel *c; | |
331 | ||
332 | for (i = 0; i < channels_alloc; i++) { | |
333 | c = channels[i]; | |
334 | if (c != NULL) { | |
335 | max = MAX(max, c->rfd); | |
336 | max = MAX(max, c->wfd); | |
337 | max = MAX(max, c->efd); | |
338 | } | |
339 | } | |
340 | return max; | |
341 | } | |
342 | ||
343 | int | |
344 | channel_close_fd(int *fdp) | |
345 | { | |
346 | int ret = 0, fd = *fdp; | |
347 | ||
348 | if (fd != -1) { | |
349 | ret = close(fd); | |
350 | *fdp = -1; | |
351 | if (fd == channel_max_fd) | |
352 | channel_max_fd = channel_find_maxfd(); | |
353 | } | |
354 | return ret; | |
355 | } | |
356 | ||
357 | /* Close all channel fd/socket. */ | |
358 | static void | |
359 | channel_close_fds(Channel *c) | |
360 | { | |
361 | debug3("channel %d: close_fds r %d w %d e %d c %d", | |
362 | c->self, c->rfd, c->wfd, c->efd, c->ctl_fd); | |
363 | ||
364 | channel_close_fd(&c->sock); | |
365 | channel_close_fd(&c->ctl_fd); | |
366 | channel_close_fd(&c->rfd); | |
367 | channel_close_fd(&c->wfd); | |
368 | channel_close_fd(&c->efd); | |
369 | } | |
370 | ||
371 | /* Free the channel and close its fd/socket. */ | |
372 | void | |
373 | channel_free(Channel *c) | |
374 | { | |
375 | char *s; | |
376 | u_int i, n; | |
377 | ||
378 | for (n = 0, i = 0; i < channels_alloc; i++) | |
379 | if (channels[i]) | |
380 | n++; | |
381 | debug("channel %d: free: %s, nchannels %u", c->self, | |
382 | c->remote_name ? c->remote_name : "???", n); | |
383 | ||
384 | s = channel_open_message(); | |
385 | debug3("channel %d: status: %s", c->self, s); | |
386 | xfree(s); | |
387 | ||
388 | if (c->sock != -1) | |
389 | shutdown(c->sock, SHUT_RDWR); | |
390 | if (c->ctl_fd != -1) | |
391 | shutdown(c->ctl_fd, SHUT_RDWR); | |
392 | channel_close_fds(c); | |
393 | buffer_free(&c->input); | |
394 | buffer_free(&c->output); | |
395 | buffer_free(&c->extended); | |
396 | if (c->remote_name) { | |
397 | xfree(c->remote_name); | |
398 | c->remote_name = NULL; | |
399 | } | |
400 | channels[c->self] = NULL; | |
401 | xfree(c); | |
402 | } | |
403 | ||
404 | void | |
405 | channel_free_all(void) | |
406 | { | |
407 | u_int i; | |
408 | ||
409 | for (i = 0; i < channels_alloc; i++) | |
410 | if (channels[i] != NULL) | |
411 | channel_free(channels[i]); | |
412 | } | |
413 | ||
414 | /* | |
415 | * Closes the sockets/fds of all channels. This is used to close extra file | |
416 | * descriptors after a fork. | |
417 | */ | |
418 | void | |
419 | channel_close_all(void) | |
420 | { | |
421 | u_int i; | |
422 | ||
423 | for (i = 0; i < channels_alloc; i++) | |
424 | if (channels[i] != NULL) | |
425 | channel_close_fds(channels[i]); | |
426 | } | |
427 | ||
428 | /* | |
429 | * Stop listening to channels. | |
430 | */ | |
431 | void | |
432 | channel_stop_listening(void) | |
433 | { | |
434 | u_int i; | |
435 | Channel *c; | |
436 | ||
437 | for (i = 0; i < channels_alloc; i++) { | |
438 | c = channels[i]; | |
439 | if (c != NULL) { | |
440 | switch (c->type) { | |
441 | case SSH_CHANNEL_AUTH_SOCKET: | |
442 | case SSH_CHANNEL_PORT_LISTENER: | |
443 | case SSH_CHANNEL_RPORT_LISTENER: | |
444 | case SSH_CHANNEL_X11_LISTENER: | |
445 | channel_close_fd(&c->sock); | |
446 | channel_free(c); | |
447 | break; | |
448 | } | |
449 | } | |
450 | } | |
451 | } | |
452 | ||
453 | /* | |
454 | * Returns true if no channel has too much buffered data, and false if one or | |
455 | * more channel is overfull. | |
456 | */ | |
457 | int | |
458 | channel_not_very_much_buffered_data(void) | |
459 | { | |
460 | u_int i; | |
461 | Channel *c; | |
462 | ||
463 | for (i = 0; i < channels_alloc; i++) { | |
464 | c = channels[i]; | |
465 | if (c != NULL && c->type == SSH_CHANNEL_OPEN) { | |
466 | #if 0 | |
467 | if (!compat20 && | |
468 | buffer_len(&c->input) > packet_get_maxsize()) { | |
469 | debug2("channel %d: big input buffer %d", | |
470 | c->self, buffer_len(&c->input)); | |
471 | return 0; | |
472 | } | |
473 | #endif | |
474 | if (buffer_len(&c->output) > packet_get_maxsize()) { | |
475 | debug2("channel %d: big output buffer %u > %u", | |
476 | c->self, buffer_len(&c->output), | |
477 | packet_get_maxsize()); | |
478 | return 0; | |
479 | } | |
480 | } | |
481 | } | |
482 | return 1; | |
483 | } | |
484 | ||
485 | /* Returns true if any channel is still open. */ | |
486 | int | |
487 | channel_still_open(void) | |
488 | { | |
489 | u_int i; | |
490 | Channel *c; | |
491 | ||
492 | for (i = 0; i < channels_alloc; i++) { | |
493 | c = channels[i]; | |
494 | if (c == NULL) | |
495 | continue; | |
496 | switch (c->type) { | |
497 | case SSH_CHANNEL_X11_LISTENER: | |
498 | case SSH_CHANNEL_PORT_LISTENER: | |
499 | case SSH_CHANNEL_RPORT_LISTENER: | |
500 | case SSH_CHANNEL_CLOSED: | |
501 | case SSH_CHANNEL_AUTH_SOCKET: | |
502 | case SSH_CHANNEL_DYNAMIC: | |
503 | case SSH_CHANNEL_CONNECTING: | |
504 | case SSH_CHANNEL_ZOMBIE: | |
505 | continue; | |
506 | case SSH_CHANNEL_LARVAL: | |
507 | if (!compat20) | |
508 | fatal("cannot happen: SSH_CHANNEL_LARVAL"); | |
509 | continue; | |
510 | case SSH_CHANNEL_OPENING: | |
511 | case SSH_CHANNEL_OPEN: | |
512 | case SSH_CHANNEL_X11_OPEN: | |
513 | return 1; | |
514 | case SSH_CHANNEL_INPUT_DRAINING: | |
515 | case SSH_CHANNEL_OUTPUT_DRAINING: | |
516 | if (!compat13) | |
517 | fatal("cannot happen: OUT_DRAIN"); | |
518 | return 1; | |
519 | default: | |
520 | fatal("channel_still_open: bad channel type %d", c->type); | |
521 | /* NOTREACHED */ | |
522 | } | |
523 | } | |
524 | return 0; | |
525 | } | |
526 | ||
527 | /* Returns the id of an open channel suitable for keepaliving */ | |
528 | int | |
529 | channel_find_open(void) | |
530 | { | |
531 | u_int i; | |
532 | Channel *c; | |
533 | ||
534 | for (i = 0; i < channels_alloc; i++) { | |
535 | c = channels[i]; | |
536 | if (c == NULL || c->remote_id < 0) | |
537 | continue; | |
538 | switch (c->type) { | |
539 | case SSH_CHANNEL_CLOSED: | |
540 | case SSH_CHANNEL_DYNAMIC: | |
541 | case SSH_CHANNEL_X11_LISTENER: | |
542 | case SSH_CHANNEL_PORT_LISTENER: | |
543 | case SSH_CHANNEL_RPORT_LISTENER: | |
544 | case SSH_CHANNEL_OPENING: | |
545 | case SSH_CHANNEL_CONNECTING: | |
546 | case SSH_CHANNEL_ZOMBIE: | |
547 | continue; | |
548 | case SSH_CHANNEL_LARVAL: | |
549 | case SSH_CHANNEL_AUTH_SOCKET: | |
550 | case SSH_CHANNEL_OPEN: | |
551 | case SSH_CHANNEL_X11_OPEN: | |
552 | return i; | |
553 | case SSH_CHANNEL_INPUT_DRAINING: | |
554 | case SSH_CHANNEL_OUTPUT_DRAINING: | |
555 | if (!compat13) | |
556 | fatal("cannot happen: OUT_DRAIN"); | |
557 | return i; | |
558 | default: | |
559 | fatal("channel_find_open: bad channel type %d", c->type); | |
560 | /* NOTREACHED */ | |
561 | } | |
562 | } | |
563 | return -1; | |
564 | } | |
565 | ||
566 | ||
567 | /* | |
568 | * Returns a message describing the currently open forwarded connections, | |
569 | * suitable for sending to the client. The message contains crlf pairs for | |
570 | * newlines. | |
571 | */ | |
572 | char * | |
573 | channel_open_message(void) | |
574 | { | |
575 | Buffer buffer; | |
576 | Channel *c; | |
577 | char buf[1024], *cp; | |
578 | u_int i; | |
579 | ||
580 | buffer_init(&buffer); | |
581 | snprintf(buf, sizeof buf, "The following connections are open:\r\n"); | |
582 | buffer_append(&buffer, buf, strlen(buf)); | |
583 | for (i = 0; i < channels_alloc; i++) { | |
584 | c = channels[i]; | |
585 | if (c == NULL) | |
586 | continue; | |
587 | switch (c->type) { | |
588 | case SSH_CHANNEL_X11_LISTENER: | |
589 | case SSH_CHANNEL_PORT_LISTENER: | |
590 | case SSH_CHANNEL_RPORT_LISTENER: | |
591 | case SSH_CHANNEL_CLOSED: | |
592 | case SSH_CHANNEL_AUTH_SOCKET: | |
593 | case SSH_CHANNEL_ZOMBIE: | |
594 | continue; | |
595 | case SSH_CHANNEL_LARVAL: | |
596 | case SSH_CHANNEL_OPENING: | |
597 | case SSH_CHANNEL_CONNECTING: | |
598 | case SSH_CHANNEL_DYNAMIC: | |
599 | case SSH_CHANNEL_OPEN: | |
600 | case SSH_CHANNEL_X11_OPEN: | |
601 | case SSH_CHANNEL_INPUT_DRAINING: | |
602 | case SSH_CHANNEL_OUTPUT_DRAINING: | |
603 | snprintf(buf, sizeof buf, | |
604 | " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d cfd %d)\r\n", | |
605 | c->self, c->remote_name, | |
606 | c->type, c->remote_id, | |
607 | c->istate, buffer_len(&c->input), | |
608 | c->ostate, buffer_len(&c->output), | |
609 | c->rfd, c->wfd, c->ctl_fd); | |
610 | buffer_append(&buffer, buf, strlen(buf)); | |
611 | continue; | |
612 | default: | |
613 | fatal("channel_open_message: bad channel type %d", c->type); | |
614 | /* NOTREACHED */ | |
615 | } | |
616 | } | |
617 | buffer_append(&buffer, "\0", 1); | |
618 | cp = xstrdup(buffer_ptr(&buffer)); | |
619 | buffer_free(&buffer); | |
620 | return cp; | |
621 | } | |
622 | ||
623 | void | |
624 | channel_send_open(int id) | |
625 | { | |
626 | Channel *c = channel_lookup(id); | |
627 | ||
628 | if (c == NULL) { | |
629 | logit("channel_send_open: %d: bad id", id); | |
630 | return; | |
631 | } | |
632 | debug2("channel %d: send open", id); | |
633 | packet_start(SSH2_MSG_CHANNEL_OPEN); | |
634 | packet_put_cstring(c->ctype); | |
635 | packet_put_int(c->self); | |
636 | packet_put_int(c->local_window); | |
637 | packet_put_int(c->local_maxpacket); | |
638 | packet_send(); | |
639 | } | |
640 | ||
641 | void | |
642 | channel_request_start(int id, char *service, int wantconfirm) | |
643 | { | |
644 | Channel *c = channel_lookup(id); | |
645 | ||
646 | if (c == NULL) { | |
647 | logit("channel_request_start: %d: unknown channel id", id); | |
648 | return; | |
649 | } | |
650 | debug2("channel %d: request %s confirm %d", id, service, wantconfirm); | |
651 | packet_start(SSH2_MSG_CHANNEL_REQUEST); | |
652 | packet_put_int(c->remote_id); | |
653 | packet_put_cstring(service); | |
654 | packet_put_char(wantconfirm); | |
655 | } | |
656 | ||
657 | void | |
658 | channel_register_confirm(int id, channel_callback_fn *fn, void *ctx) | |
659 | { | |
660 | Channel *c = channel_lookup(id); | |
661 | ||
662 | if (c == NULL) { | |
663 | logit("channel_register_comfirm: %d: bad id", id); | |
664 | return; | |
665 | } | |
666 | c->confirm = fn; | |
667 | c->confirm_ctx = ctx; | |
668 | } | |
669 | ||
670 | void | |
671 | channel_register_cleanup(int id, channel_callback_fn *fn, int do_close) | |
672 | { | |
673 | Channel *c = channel_by_id(id); | |
674 | ||
675 | if (c == NULL) { | |
676 | logit("channel_register_cleanup: %d: bad id", id); | |
677 | return; | |
678 | } | |
679 | c->detach_user = fn; | |
680 | c->detach_close = do_close; | |
681 | } | |
682 | ||
683 | void | |
684 | channel_cancel_cleanup(int id) | |
685 | { | |
686 | Channel *c = channel_by_id(id); | |
687 | ||
688 | if (c == NULL) { | |
689 | logit("channel_cancel_cleanup: %d: bad id", id); | |
690 | return; | |
691 | } | |
692 | c->detach_user = NULL; | |
693 | c->detach_close = 0; | |
694 | } | |
695 | ||
696 | void | |
697 | channel_register_filter(int id, channel_infilter_fn *ifn, | |
698 | channel_outfilter_fn *ofn) | |
699 | { | |
700 | Channel *c = channel_lookup(id); | |
701 | ||
702 | if (c == NULL) { | |
703 | logit("channel_register_filter: %d: bad id", id); | |
704 | return; | |
705 | } | |
706 | c->input_filter = ifn; | |
707 | c->output_filter = ofn; | |
708 | } | |
709 | ||
710 | void | |
711 | channel_set_fds(int id, int rfd, int wfd, int efd, | |
712 | int extusage, int nonblock, u_int window_max) | |
713 | { | |
714 | Channel *c = channel_lookup(id); | |
715 | ||
716 | if (c == NULL || c->type != SSH_CHANNEL_LARVAL) | |
717 | fatal("channel_activate for non-larval channel %d.", id); | |
718 | channel_register_fds(c, rfd, wfd, efd, extusage, nonblock); | |
719 | c->type = SSH_CHANNEL_OPEN; | |
720 | c->local_window = c->local_window_max = window_max; | |
721 | packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST); | |
722 | packet_put_int(c->remote_id); | |
723 | packet_put_int(c->local_window); | |
724 | packet_send(); | |
725 | } | |
726 | ||
727 | /* | |
728 | * 'channel_pre*' are called just before select() to add any bits relevant to | |
729 | * channels in the select bitmasks. | |
730 | */ | |
731 | /* | |
732 | * 'channel_post*': perform any appropriate operations for channels which | |
733 | * have events pending. | |
734 | */ | |
735 | typedef void chan_fn(Channel *c, fd_set *readset, fd_set *writeset); | |
736 | chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE]; | |
737 | chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE]; | |
738 | ||
739 | static void | |
740 | channel_pre_listener(Channel *c, fd_set *readset, fd_set *writeset) | |
741 | { | |
742 | FD_SET(c->sock, readset); | |
743 | } | |
744 | ||
745 | static void | |
746 | channel_pre_connecting(Channel *c, fd_set *readset, fd_set *writeset) | |
747 | { | |
748 | debug3("channel %d: waiting for connection", c->self); | |
749 | FD_SET(c->sock, writeset); | |
750 | } | |
751 | ||
752 | static void | |
753 | channel_pre_open_13(Channel *c, fd_set *readset, fd_set *writeset) | |
754 | { | |
755 | if (buffer_len(&c->input) < packet_get_maxsize()) | |
756 | FD_SET(c->sock, readset); | |
757 | if (buffer_len(&c->output) > 0) | |
758 | FD_SET(c->sock, writeset); | |
759 | } | |
760 | ||
761 | static void | |
762 | channel_pre_open(Channel *c, fd_set *readset, fd_set *writeset) | |
763 | { | |
764 | u_int limit = compat20 ? c->remote_window : packet_get_maxsize(); | |
765 | ||
766 | if (c->istate == CHAN_INPUT_OPEN && | |
767 | limit > 0 && | |
768 | buffer_len(&c->input) < limit && | |
769 | buffer_check_alloc(&c->input, CHAN_RBUF)) | |
770 | FD_SET(c->rfd, readset); | |
771 | if (c->ostate == CHAN_OUTPUT_OPEN || | |
772 | c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { | |
773 | if (buffer_len(&c->output) > 0) { | |
774 | FD_SET(c->wfd, writeset); | |
775 | } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { | |
776 | if (CHANNEL_EFD_OUTPUT_ACTIVE(c)) | |
777 | debug2("channel %d: obuf_empty delayed efd %d/(%d)", | |
778 | c->self, c->efd, buffer_len(&c->extended)); | |
779 | else | |
780 | chan_obuf_empty(c); | |
781 | } | |
782 | } | |
783 | /** XXX check close conditions, too */ | |
784 | if (compat20 && c->efd != -1) { | |
785 | if (c->extended_usage == CHAN_EXTENDED_WRITE && | |
786 | buffer_len(&c->extended) > 0) | |
787 | FD_SET(c->efd, writeset); | |
788 | else if (!(c->flags & CHAN_EOF_SENT) && | |
789 | c->extended_usage == CHAN_EXTENDED_READ && | |
790 | buffer_len(&c->extended) < c->remote_window) | |
791 | FD_SET(c->efd, readset); | |
792 | } | |
793 | /* XXX: What about efd? races? */ | |
794 | if (compat20 && c->ctl_fd != -1 && | |
795 | c->istate == CHAN_INPUT_OPEN && c->ostate == CHAN_OUTPUT_OPEN) | |
796 | FD_SET(c->ctl_fd, readset); | |
797 | } | |
798 | ||
799 | static void | |
800 | channel_pre_input_draining(Channel *c, fd_set *readset, fd_set *writeset) | |
801 | { | |
802 | if (buffer_len(&c->input) == 0) { | |
803 | packet_start(SSH_MSG_CHANNEL_CLOSE); | |
804 | packet_put_int(c->remote_id); | |
805 | packet_send(); | |
806 | c->type = SSH_CHANNEL_CLOSED; | |
807 | debug2("channel %d: closing after input drain.", c->self); | |
808 | } | |
809 | } | |
810 | ||
811 | static void | |
812 | channel_pre_output_draining(Channel *c, fd_set *readset, fd_set *writeset) | |
813 | { | |
814 | if (buffer_len(&c->output) == 0) | |
815 | chan_mark_dead(c); | |
816 | else | |
817 | FD_SET(c->sock, writeset); | |
818 | } | |
819 | ||
820 | /* | |
821 | * This is a special state for X11 authentication spoofing. An opened X11 | |
822 | * connection (when authentication spoofing is being done) remains in this | |
823 | * state until the first packet has been completely read. The authentication | |
824 | * data in that packet is then substituted by the real data if it matches the | |
825 | * fake data, and the channel is put into normal mode. | |
826 | * XXX All this happens at the client side. | |
827 | * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok | |
828 | */ | |
829 | static int | |
830 | x11_open_helper(Buffer *b) | |
831 | { | |
832 | u_char *ucp; | |
833 | u_int proto_len, data_len; | |
834 | ||
835 | /* Check if the fixed size part of the packet is in buffer. */ | |
836 | if (buffer_len(b) < 12) | |
837 | return 0; | |
838 | ||
839 | /* Parse the lengths of variable-length fields. */ | |
840 | ucp = buffer_ptr(b); | |
841 | if (ucp[0] == 0x42) { /* Byte order MSB first. */ | |
842 | proto_len = 256 * ucp[6] + ucp[7]; | |
843 | data_len = 256 * ucp[8] + ucp[9]; | |
844 | } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */ | |
845 | proto_len = ucp[6] + 256 * ucp[7]; | |
846 | data_len = ucp[8] + 256 * ucp[9]; | |
847 | } else { | |
848 | debug2("Initial X11 packet contains bad byte order byte: 0x%x", | |
849 | ucp[0]); | |
850 | return -1; | |
851 | } | |
852 | ||
853 | /* Check if the whole packet is in buffer. */ | |
854 | if (buffer_len(b) < | |
855 | 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3)) | |
856 | return 0; | |
857 | ||
858 | /* Check if authentication protocol matches. */ | |
859 | if (proto_len != strlen(x11_saved_proto) || | |
860 | memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) { | |
861 | debug2("X11 connection uses different authentication protocol."); | |
862 | return -1; | |
863 | } | |
864 | /* Check if authentication data matches our fake data. */ | |
865 | if (data_len != x11_fake_data_len || | |
866 | memcmp(ucp + 12 + ((proto_len + 3) & ~3), | |
867 | x11_fake_data, x11_fake_data_len) != 0) { | |
868 | debug2("X11 auth data does not match fake data."); | |
869 | return -1; | |
870 | } | |
871 | /* Check fake data length */ | |
872 | if (x11_fake_data_len != x11_saved_data_len) { | |
873 | error("X11 fake_data_len %d != saved_data_len %d", | |
874 | x11_fake_data_len, x11_saved_data_len); | |
875 | return -1; | |
876 | } | |
877 | /* | |
878 | * Received authentication protocol and data match | |
879 | * our fake data. Substitute the fake data with real | |
880 | * data. | |
881 | */ | |
882 | memcpy(ucp + 12 + ((proto_len + 3) & ~3), | |
883 | x11_saved_data, x11_saved_data_len); | |
884 | return 1; | |
885 | } | |
886 | ||
887 | static void | |
888 | channel_pre_x11_open_13(Channel *c, fd_set *readset, fd_set *writeset) | |
889 | { | |
890 | int ret = x11_open_helper(&c->output); | |
891 | ||
892 | if (ret == 1) { | |
893 | /* Start normal processing for the channel. */ | |
894 | c->type = SSH_CHANNEL_OPEN; | |
895 | channel_pre_open_13(c, readset, writeset); | |
896 | } else if (ret == -1) { | |
897 | /* | |
898 | * We have received an X11 connection that has bad | |
899 | * authentication information. | |
900 | */ | |
901 | logit("X11 connection rejected because of wrong authentication."); | |
902 | buffer_clear(&c->input); | |
903 | buffer_clear(&c->output); | |
904 | channel_close_fd(&c->sock); | |
905 | c->sock = -1; | |
906 | c->type = SSH_CHANNEL_CLOSED; | |
907 | packet_start(SSH_MSG_CHANNEL_CLOSE); | |
908 | packet_put_int(c->remote_id); | |
909 | packet_send(); | |
910 | } | |
911 | } | |
912 | ||
913 | static void | |
914 | channel_pre_x11_open(Channel *c, fd_set *readset, fd_set *writeset) | |
915 | { | |
916 | int ret = x11_open_helper(&c->output); | |
917 | ||
918 | /* c->force_drain = 1; */ | |
919 | ||
920 | if (ret == 1) { | |
921 | c->type = SSH_CHANNEL_OPEN; | |
922 | channel_pre_open(c, readset, writeset); | |
923 | } else if (ret == -1) { | |
924 | logit("X11 connection rejected because of wrong authentication."); | |
925 | debug2("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate); | |
926 | chan_read_failed(c); | |
927 | buffer_clear(&c->input); | |
928 | chan_ibuf_empty(c); | |
929 | buffer_clear(&c->output); | |
930 | /* for proto v1, the peer will send an IEOF */ | |
931 | if (compat20) | |
932 | chan_write_failed(c); | |
933 | else | |
934 | c->type = SSH_CHANNEL_OPEN; | |
935 | debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate); | |
936 | } | |
937 | } | |
938 | ||
939 | /* try to decode a socks4 header */ | |
940 | static int | |
941 | channel_decode_socks4(Channel *c, fd_set *readset, fd_set *writeset) | |
942 | { | |
943 | char *p, *host; | |
944 | u_int len, have, i, found; | |
945 | char username[256]; | |
946 | struct { | |
947 | u_int8_t version; | |
948 | u_int8_t command; | |
949 | u_int16_t dest_port; | |
950 | struct in_addr dest_addr; | |
951 | } s4_req, s4_rsp; | |
952 | ||
953 | debug2("channel %d: decode socks4", c->self); | |
954 | ||
955 | have = buffer_len(&c->input); | |
956 | len = sizeof(s4_req); | |
957 | if (have < len) | |
958 | return 0; | |
959 | p = buffer_ptr(&c->input); | |
960 | for (found = 0, i = len; i < have; i++) { | |
961 | if (p[i] == '\0') { | |
962 | found = 1; | |
963 | break; | |
964 | } | |
965 | if (i > 1024) { | |
966 | /* the peer is probably sending garbage */ | |
967 | debug("channel %d: decode socks4: too long", | |
968 | c->self); | |
969 | return -1; | |
970 | } | |
971 | } | |
972 | if (!found) | |
973 | return 0; | |
974 | buffer_get(&c->input, (char *)&s4_req.version, 1); | |
975 | buffer_get(&c->input, (char *)&s4_req.command, 1); | |
976 | buffer_get(&c->input, (char *)&s4_req.dest_port, 2); | |
977 | buffer_get(&c->input, (char *)&s4_req.dest_addr, 4); | |
978 | have = buffer_len(&c->input); | |
979 | p = buffer_ptr(&c->input); | |
980 | len = strlen(p); | |
981 | debug2("channel %d: decode socks4: user %s/%d", c->self, p, len); | |
982 | if (len > have) | |
983 | fatal("channel %d: decode socks4: len %d > have %d", | |
984 | c->self, len, have); | |
985 | strlcpy(username, p, sizeof(username)); | |
986 | buffer_consume(&c->input, len); | |
987 | buffer_consume(&c->input, 1); /* trailing '\0' */ | |
988 | ||
989 | host = inet_ntoa(s4_req.dest_addr); | |
990 | strlcpy(c->path, host, sizeof(c->path)); | |
991 | c->host_port = ntohs(s4_req.dest_port); | |
992 | ||
993 | debug2("channel %d: dynamic request: socks4 host %s port %u command %u", | |
994 | c->self, host, c->host_port, s4_req.command); | |
995 | ||
996 | if (s4_req.command != 1) { | |
997 | debug("channel %d: cannot handle: socks4 cn %d", | |
998 | c->self, s4_req.command); | |
999 | return -1; | |
1000 | } | |
1001 | s4_rsp.version = 0; /* vn: 0 for reply */ | |
1002 | s4_rsp.command = 90; /* cd: req granted */ | |
1003 | s4_rsp.dest_port = 0; /* ignored */ | |
1004 | s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */ | |
1005 | buffer_append(&c->output, &s4_rsp, sizeof(s4_rsp)); | |
1006 | return 1; | |
1007 | } | |
1008 | ||
1009 | /* try to decode a socks5 header */ | |
1010 | #define SSH_SOCKS5_AUTHDONE 0x1000 | |
1011 | #define SSH_SOCKS5_NOAUTH 0x00 | |
1012 | #define SSH_SOCKS5_IPV4 0x01 | |
1013 | #define SSH_SOCKS5_DOMAIN 0x03 | |
1014 | #define SSH_SOCKS5_IPV6 0x04 | |
1015 | #define SSH_SOCKS5_CONNECT 0x01 | |
1016 | #define SSH_SOCKS5_SUCCESS 0x00 | |
1017 | ||
1018 | static int | |
1019 | channel_decode_socks5(Channel *c, fd_set *readset, fd_set *writeset) | |
1020 | { | |
1021 | struct { | |
1022 | u_int8_t version; | |
1023 | u_int8_t command; | |
1024 | u_int8_t reserved; | |
1025 | u_int8_t atyp; | |
1026 | } s5_req, s5_rsp; | |
1027 | u_int16_t dest_port; | |
1028 | u_char *p, dest_addr[255+1]; | |
1029 | u_int have, need, i, found, nmethods, addrlen, af; | |
1030 | ||
1031 | debug2("channel %d: decode socks5", c->self); | |
1032 | p = buffer_ptr(&c->input); | |
1033 | if (p[0] != 0x05) | |
1034 | return -1; | |
1035 | have = buffer_len(&c->input); | |
1036 | if (!(c->flags & SSH_SOCKS5_AUTHDONE)) { | |
1037 | /* format: ver | nmethods | methods */ | |
1038 | if (have < 2) | |
1039 | return 0; | |
1040 | nmethods = p[1]; | |
1041 | if (have < nmethods + 2) | |
1042 | return 0; | |
1043 | /* look for method: "NO AUTHENTICATION REQUIRED" */ | |
1044 | for (found = 0, i = 2 ; i < nmethods + 2; i++) { | |
1045 | if (p[i] == SSH_SOCKS5_NOAUTH ) { | |
1046 | found = 1; | |
1047 | break; | |
1048 | } | |
1049 | } | |
1050 | if (!found) { | |
1051 | debug("channel %d: method SSH_SOCKS5_NOAUTH not found", | |
1052 | c->self); | |
1053 | return -1; | |
1054 | } | |
1055 | buffer_consume(&c->input, nmethods + 2); | |
1056 | buffer_put_char(&c->output, 0x05); /* version */ | |
1057 | buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH); /* method */ | |
1058 | FD_SET(c->sock, writeset); | |
1059 | c->flags |= SSH_SOCKS5_AUTHDONE; | |
1060 | debug2("channel %d: socks5 auth done", c->self); | |
1061 | return 0; /* need more */ | |
1062 | } | |
1063 | debug2("channel %d: socks5 post auth", c->self); | |
1064 | if (have < sizeof(s5_req)+1) | |
1065 | return 0; /* need more */ | |
1066 | memcpy(&s5_req, p, sizeof(s5_req)); | |
1067 | if (s5_req.version != 0x05 || | |
1068 | s5_req.command != SSH_SOCKS5_CONNECT || | |
1069 | s5_req.reserved != 0x00) { | |
1070 | debug2("channel %d: only socks5 connect supported", c->self); | |
1071 | return -1; | |
1072 | } | |
1073 | switch (s5_req.atyp){ | |
1074 | case SSH_SOCKS5_IPV4: | |
1075 | addrlen = 4; | |
1076 | af = AF_INET; | |
1077 | break; | |
1078 | case SSH_SOCKS5_DOMAIN: | |
1079 | addrlen = p[sizeof(s5_req)]; | |
1080 | af = -1; | |
1081 | break; | |
1082 | case SSH_SOCKS5_IPV6: | |
1083 | addrlen = 16; | |
1084 | af = AF_INET6; | |
1085 | break; | |
1086 | default: | |
1087 | debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp); | |
1088 | return -1; | |
1089 | } | |
1090 | need = sizeof(s5_req) + addrlen + 2; | |
1091 | if (s5_req.atyp == SSH_SOCKS5_DOMAIN) | |
1092 | need++; | |
1093 | if (have < need) | |
1094 | return 0; | |
1095 | buffer_consume(&c->input, sizeof(s5_req)); | |
1096 | if (s5_req.atyp == SSH_SOCKS5_DOMAIN) | |
1097 | buffer_consume(&c->input, 1); /* host string length */ | |
1098 | buffer_get(&c->input, (char *)&dest_addr, addrlen); | |
1099 | buffer_get(&c->input, (char *)&dest_port, 2); | |
1100 | dest_addr[addrlen] = '\0'; | |
1101 | if (s5_req.atyp == SSH_SOCKS5_DOMAIN) | |
1102 | strlcpy(c->path, (char *)dest_addr, sizeof(c->path)); | |
1103 | else if (inet_ntop(af, dest_addr, c->path, sizeof(c->path)) == NULL) | |
1104 | return -1; | |
1105 | c->host_port = ntohs(dest_port); | |
1106 | ||
1107 | debug2("channel %d: dynamic request: socks5 host %s port %u command %u", | |
1108 | c->self, c->path, c->host_port, s5_req.command); | |
1109 | ||
1110 | s5_rsp.version = 0x05; | |
1111 | s5_rsp.command = SSH_SOCKS5_SUCCESS; | |
1112 | s5_rsp.reserved = 0; /* ignored */ | |
1113 | s5_rsp.atyp = SSH_SOCKS5_IPV4; | |
1114 | ((struct in_addr *)&dest_addr)->s_addr = INADDR_ANY; | |
1115 | dest_port = 0; /* ignored */ | |
1116 | ||
1117 | buffer_append(&c->output, &s5_rsp, sizeof(s5_rsp)); | |
1118 | buffer_append(&c->output, &dest_addr, sizeof(struct in_addr)); | |
1119 | buffer_append(&c->output, &dest_port, sizeof(dest_port)); | |
1120 | return 1; | |
1121 | } | |
1122 | ||
1123 | /* dynamic port forwarding */ | |
1124 | static void | |
1125 | channel_pre_dynamic(Channel *c, fd_set *readset, fd_set *writeset) | |
1126 | { | |
1127 | u_char *p; | |
1128 | u_int have; | |
1129 | int ret; | |
1130 | ||
1131 | have = buffer_len(&c->input); | |
1132 | c->delayed = 0; | |
1133 | debug2("channel %d: pre_dynamic: have %d", c->self, have); | |
1134 | /* buffer_dump(&c->input); */ | |
1135 | /* check if the fixed size part of the packet is in buffer. */ | |
1136 | if (have < 3) { | |
1137 | /* need more */ | |
1138 | FD_SET(c->sock, readset); | |
1139 | return; | |
1140 | } | |
1141 | /* try to guess the protocol */ | |
1142 | p = buffer_ptr(&c->input); | |
1143 | switch (p[0]) { | |
1144 | case 0x04: | |
1145 | ret = channel_decode_socks4(c, readset, writeset); | |
1146 | break; | |
1147 | case 0x05: | |
1148 | ret = channel_decode_socks5(c, readset, writeset); | |
1149 | break; | |
1150 | default: | |
1151 | ret = -1; | |
1152 | break; | |
1153 | } | |
1154 | if (ret < 0) { | |
1155 | chan_mark_dead(c); | |
1156 | } else if (ret == 0) { | |
1157 | debug2("channel %d: pre_dynamic: need more", c->self); | |
1158 | /* need more */ | |
1159 | FD_SET(c->sock, readset); | |
1160 | } else { | |
1161 | /* switch to the next state */ | |
1162 | c->type = SSH_CHANNEL_OPENING; | |
1163 | port_open_helper(c, "direct-tcpip"); | |
1164 | } | |
1165 | } | |
1166 | ||
1167 | /* This is our fake X11 server socket. */ | |
1168 | static void | |
1169 | channel_post_x11_listener(Channel *c, fd_set *readset, fd_set *writeset) | |
1170 | { | |
1171 | Channel *nc; | |
1172 | struct sockaddr addr; | |
1173 | int newsock; | |
1174 | socklen_t addrlen; | |
1175 | char buf[16384], *remote_ipaddr; | |
1176 | int remote_port; | |
1177 | ||
1178 | if (FD_ISSET(c->sock, readset)) { | |
1179 | debug("X11 connection requested."); | |
1180 | addrlen = sizeof(addr); | |
1181 | newsock = accept(c->sock, &addr, &addrlen); | |
1182 | if (c->single_connection) { | |
1183 | debug2("single_connection: closing X11 listener."); | |
1184 | channel_close_fd(&c->sock); | |
1185 | chan_mark_dead(c); | |
1186 | } | |
1187 | if (newsock < 0) { | |
1188 | error("accept: %.100s", strerror(errno)); | |
1189 | return; | |
1190 | } | |
1191 | set_nodelay(newsock); | |
1192 | remote_ipaddr = get_peer_ipaddr(newsock); | |
1193 | remote_port = get_peer_port(newsock); | |
1194 | snprintf(buf, sizeof buf, "X11 connection from %.200s port %d", | |
1195 | remote_ipaddr, remote_port); | |
1196 | ||
1197 | nc = channel_new("accepted x11 socket", | |
1198 | SSH_CHANNEL_OPENING, newsock, newsock, -1, | |
1199 | c->local_window_max, c->local_maxpacket, 0, buf, 1); | |
1200 | if (compat20) { | |
1201 | packet_start(SSH2_MSG_CHANNEL_OPEN); | |
1202 | packet_put_cstring("x11"); | |
1203 | packet_put_int(nc->self); | |
1204 | packet_put_int(nc->local_window_max); | |
1205 | packet_put_int(nc->local_maxpacket); | |
1206 | /* originator ipaddr and port */ | |
1207 | packet_put_cstring(remote_ipaddr); | |
1208 | if (datafellows & SSH_BUG_X11FWD) { | |
1209 | debug2("ssh2 x11 bug compat mode"); | |
1210 | } else { | |
1211 | packet_put_int(remote_port); | |
1212 | } | |
1213 | packet_send(); | |
1214 | } else { | |
1215 | packet_start(SSH_SMSG_X11_OPEN); | |
1216 | packet_put_int(nc->self); | |
1217 | if (packet_get_protocol_flags() & | |
1218 | SSH_PROTOFLAG_HOST_IN_FWD_OPEN) | |
1219 | packet_put_cstring(buf); | |
1220 | packet_send(); | |
1221 | } | |
1222 | xfree(remote_ipaddr); | |
1223 | } | |
1224 | } | |
1225 | ||
1226 | static void | |
1227 | port_open_helper(Channel *c, char *rtype) | |
1228 | { | |
1229 | int direct; | |
1230 | char buf[1024]; | |
1231 | char *remote_ipaddr = get_peer_ipaddr(c->sock); | |
1232 | int remote_port = get_peer_port(c->sock); | |
1233 | ||
1234 | direct = (strcmp(rtype, "direct-tcpip") == 0); | |
1235 | ||
1236 | snprintf(buf, sizeof buf, | |
1237 | "%s: listening port %d for %.100s port %d, " | |
1238 | "connect from %.200s port %d", | |
1239 | rtype, c->listening_port, c->path, c->host_port, | |
1240 | remote_ipaddr, remote_port); | |
1241 | ||
1242 | xfree(c->remote_name); | |
1243 | c->remote_name = xstrdup(buf); | |
1244 | ||
1245 | if (compat20) { | |
1246 | packet_start(SSH2_MSG_CHANNEL_OPEN); | |
1247 | packet_put_cstring(rtype); | |
1248 | packet_put_int(c->self); | |
1249 | packet_put_int(c->local_window_max); | |
1250 | packet_put_int(c->local_maxpacket); | |
1251 | if (direct) { | |
1252 | /* target host, port */ | |
1253 | packet_put_cstring(c->path); | |
1254 | packet_put_int(c->host_port); | |
1255 | } else { | |
1256 | /* listen address, port */ | |
1257 | packet_put_cstring(c->path); | |
1258 | packet_put_int(c->listening_port); | |
1259 | } | |
1260 | /* originator host and port */ | |
1261 | packet_put_cstring(remote_ipaddr); | |
1262 | packet_put_int((u_int)remote_port); | |
1263 | packet_send(); | |
1264 | } else { | |
1265 | packet_start(SSH_MSG_PORT_OPEN); | |
1266 | packet_put_int(c->self); | |
1267 | packet_put_cstring(c->path); | |
1268 | packet_put_int(c->host_port); | |
1269 | if (packet_get_protocol_flags() & | |
1270 | SSH_PROTOFLAG_HOST_IN_FWD_OPEN) | |
1271 | packet_put_cstring(c->remote_name); | |
1272 | packet_send(); | |
1273 | } | |
1274 | xfree(remote_ipaddr); | |
1275 | } | |
1276 | ||
1277 | static void | |
1278 | channel_set_reuseaddr(int fd) | |
1279 | { | |
1280 | int on = 1; | |
1281 | ||
1282 | /* | |
1283 | * Set socket options. | |
1284 | * Allow local port reuse in TIME_WAIT. | |
1285 | */ | |
1286 | if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1) | |
1287 | error("setsockopt SO_REUSEADDR fd %d: %s", fd, strerror(errno)); | |
1288 | } | |
1289 | ||
1290 | /* | |
1291 | * This socket is listening for connections to a forwarded TCP/IP port. | |
1292 | */ | |
1293 | static void | |
1294 | channel_post_port_listener(Channel *c, fd_set *readset, fd_set *writeset) | |
1295 | { | |
1296 | Channel *nc; | |
1297 | struct sockaddr addr; | |
1298 | int newsock, nextstate; | |
1299 | socklen_t addrlen; | |
1300 | char *rtype; | |
1301 | ||
1302 | if (FD_ISSET(c->sock, readset)) { | |
1303 | debug("Connection to port %d forwarding " | |
1304 | "to %.100s port %d requested.", | |
1305 | c->listening_port, c->path, c->host_port); | |
1306 | ||
1307 | if (c->type == SSH_CHANNEL_RPORT_LISTENER) { | |
1308 | nextstate = SSH_CHANNEL_OPENING; | |
1309 | rtype = "forwarded-tcpip"; | |
1310 | } else { | |
1311 | if (c->host_port == 0) { | |
1312 | nextstate = SSH_CHANNEL_DYNAMIC; | |
1313 | rtype = "dynamic-tcpip"; | |
1314 | } else { | |
1315 | nextstate = SSH_CHANNEL_OPENING; | |
1316 | rtype = "direct-tcpip"; | |
1317 | } | |
1318 | } | |
1319 | ||
1320 | addrlen = sizeof(addr); | |
1321 | newsock = accept(c->sock, &addr, &addrlen); | |
1322 | if (newsock < 0) { | |
1323 | error("accept: %.100s", strerror(errno)); | |
1324 | return; | |
1325 | } | |
1326 | set_nodelay(newsock); | |
1327 | nc = channel_new(rtype, nextstate, newsock, newsock, -1, | |
1328 | c->local_window_max, c->local_maxpacket, 0, rtype, 1); | |
1329 | nc->listening_port = c->listening_port; | |
1330 | nc->host_port = c->host_port; | |
1331 | strlcpy(nc->path, c->path, sizeof(nc->path)); | |
1332 | ||
1333 | if (nextstate == SSH_CHANNEL_DYNAMIC) { | |
1334 | /* | |
1335 | * do not call the channel_post handler until | |
1336 | * this flag has been reset by a pre-handler. | |
1337 | * otherwise the FD_ISSET calls might overflow | |
1338 | */ | |
1339 | nc->delayed = 1; | |
1340 | } else { | |
1341 | port_open_helper(nc, rtype); | |
1342 | } | |
1343 | } | |
1344 | } | |
1345 | ||
1346 | /* | |
1347 | * This is the authentication agent socket listening for connections from | |
1348 | * clients. | |
1349 | */ | |
1350 | static void | |
1351 | channel_post_auth_listener(Channel *c, fd_set *readset, fd_set *writeset) | |
1352 | { | |
1353 | Channel *nc; | |
1354 | int newsock; | |
1355 | struct sockaddr addr; | |
1356 | socklen_t addrlen; | |
1357 | ||
1358 | if (FD_ISSET(c->sock, readset)) { | |
1359 | addrlen = sizeof(addr); | |
1360 | newsock = accept(c->sock, &addr, &addrlen); | |
1361 | if (newsock < 0) { | |
1362 | error("accept from auth socket: %.100s", strerror(errno)); | |
1363 | return; | |
1364 | } | |
1365 | nc = channel_new("accepted auth socket", | |
1366 | SSH_CHANNEL_OPENING, newsock, newsock, -1, | |
1367 | c->local_window_max, c->local_maxpacket, | |
1368 | 0, "accepted auth socket", 1); | |
1369 | if (compat20) { | |
1370 | packet_start(SSH2_MSG_CHANNEL_OPEN); | |
1371 | packet_put_cstring("auth-agent@openssh.com"); | |
1372 | packet_put_int(nc->self); | |
1373 | packet_put_int(c->local_window_max); | |
1374 | packet_put_int(c->local_maxpacket); | |
1375 | } else { | |
1376 | packet_start(SSH_SMSG_AGENT_OPEN); | |
1377 | packet_put_int(nc->self); | |
1378 | } | |
1379 | packet_send(); | |
1380 | } | |
1381 | } | |
1382 | ||
1383 | static void | |
1384 | channel_post_connecting(Channel *c, fd_set *readset, fd_set *writeset) | |
1385 | { | |
1386 | int err = 0; | |
1387 | socklen_t sz = sizeof(err); | |
1388 | ||
1389 | if (FD_ISSET(c->sock, writeset)) { | |
1390 | if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) { | |
1391 | err = errno; | |
1392 | error("getsockopt SO_ERROR failed"); | |
1393 | } | |
1394 | if (err == 0) { | |
1395 | debug("channel %d: connected", c->self); | |
1396 | c->type = SSH_CHANNEL_OPEN; | |
1397 | if (compat20) { | |
1398 | packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION); | |
1399 | packet_put_int(c->remote_id); | |
1400 | packet_put_int(c->self); | |
1401 | packet_put_int(c->local_window); | |
1402 | packet_put_int(c->local_maxpacket); | |
1403 | } else { | |
1404 | packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION); | |
1405 | packet_put_int(c->remote_id); | |
1406 | packet_put_int(c->self); | |
1407 | } | |
1408 | } else { | |
1409 | debug("channel %d: not connected: %s", | |
1410 | c->self, strerror(err)); | |
1411 | if (compat20) { | |
1412 | packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE); | |
1413 | packet_put_int(c->remote_id); | |
1414 | packet_put_int(SSH2_OPEN_CONNECT_FAILED); | |
1415 | if (!(datafellows & SSH_BUG_OPENFAILURE)) { | |
1416 | packet_put_cstring(strerror(err)); | |
1417 | packet_put_cstring(""); | |
1418 | } | |
1419 | } else { | |
1420 | packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); | |
1421 | packet_put_int(c->remote_id); | |
1422 | } | |
1423 | chan_mark_dead(c); | |
1424 | } | |
1425 | packet_send(); | |
1426 | } | |
1427 | } | |
1428 | ||
1429 | static int | |
1430 | channel_handle_rfd(Channel *c, fd_set *readset, fd_set *writeset) | |
1431 | { | |
1432 | char buf[CHAN_RBUF]; | |
1433 | int len; | |
1434 | ||
1435 | if (c->rfd != -1 && | |
1436 | FD_ISSET(c->rfd, readset)) { | |
1437 | errno = 0; | |
1438 | len = read(c->rfd, buf, sizeof(buf)); | |
1439 | if (len < 0 && (errno == EINTR || errno == EAGAIN)) | |
1440 | return 1; | |
1441 | #ifndef PTY_ZEROREAD | |
1442 | if (len <= 0) { | |
1443 | #else | |
1444 | if ((!c->isatty && len <= 0) || | |
1445 | (c->isatty && (len < 0 || (len == 0 && errno != 0)))) { | |
1446 | #endif | |
1447 | debug2("channel %d: read<=0 rfd %d len %d", | |
1448 | c->self, c->rfd, len); | |
1449 | if (c->type != SSH_CHANNEL_OPEN) { | |
1450 | debug2("channel %d: not open", c->self); | |
1451 | chan_mark_dead(c); | |
1452 | return -1; | |
1453 | } else if (compat13) { | |
1454 | buffer_clear(&c->output); | |
1455 | c->type = SSH_CHANNEL_INPUT_DRAINING; | |
1456 | debug2("channel %d: input draining.", c->self); | |
1457 | } else { | |
1458 | chan_read_failed(c); | |
1459 | } | |
1460 | return -1; | |
1461 | } | |
1462 | if (c->input_filter != NULL) { | |
1463 | if (c->input_filter(c, buf, len) == -1) { | |
1464 | debug2("channel %d: filter stops", c->self); | |
1465 | chan_read_failed(c); | |
1466 | } | |
1467 | } else if (c->datagram) { | |
1468 | buffer_put_string(&c->input, buf, len); | |
1469 | } else { | |
1470 | buffer_append(&c->input, buf, len); | |
1471 | } | |
1472 | } | |
1473 | return 1; | |
1474 | } | |
1475 | ||
1476 | static int | |
1477 | channel_handle_wfd(Channel *c, fd_set *readset, fd_set *writeset) | |
1478 | { | |
1479 | struct termios tio; | |
1480 | u_char *data = NULL, *buf; | |
1481 | u_int dlen; | |
1482 | int len; | |
1483 | ||
1484 | /* Send buffered output data to the socket. */ | |
1485 | if (c->wfd != -1 && | |
1486 | FD_ISSET(c->wfd, writeset) && | |
1487 | buffer_len(&c->output) > 0) { | |
1488 | if (c->output_filter != NULL) { | |
1489 | if ((buf = c->output_filter(c, &data, &dlen)) == NULL) { | |
1490 | debug2("channel %d: filter stops", c->self); | |
1491 | if (c->type != SSH_CHANNEL_OPEN) | |
1492 | chan_mark_dead(c); | |
1493 | else | |
1494 | chan_write_failed(c); | |
1495 | return -1; | |
1496 | } | |
1497 | } else if (c->datagram) { | |
1498 | buf = data = buffer_get_string(&c->output, &dlen); | |
1499 | } else { | |
1500 | buf = data = buffer_ptr(&c->output); | |
1501 | dlen = buffer_len(&c->output); | |
1502 | } | |
1503 | ||
1504 | if (c->datagram) { | |
1505 | /* ignore truncated writes, datagrams might get lost */ | |
1506 | c->local_consumed += dlen + 4; | |
1507 | len = write(c->wfd, buf, dlen); | |
1508 | xfree(data); | |
1509 | if (len < 0 && (errno == EINTR || errno == EAGAIN)) | |
1510 | return 1; | |
1511 | if (len <= 0) { | |
1512 | if (c->type != SSH_CHANNEL_OPEN) | |
1513 | chan_mark_dead(c); | |
1514 | else | |
1515 | chan_write_failed(c); | |
1516 | return -1; | |
1517 | } | |
1518 | return 1; | |
1519 | } | |
1520 | #ifdef _AIX | |
1521 | /* XXX: Later AIX versions can't push as much data to tty */ | |
1522 | if (compat20 && c->wfd_isatty) | |
1523 | dlen = MIN(dlen, 8*1024); | |
1524 | #endif | |
1525 | ||
1526 | len = write(c->wfd, buf, dlen); | |
1527 | if (len < 0 && (errno == EINTR || errno == EAGAIN)) | |
1528 | return 1; | |
1529 | if (len <= 0) { | |
1530 | if (c->type != SSH_CHANNEL_OPEN) { | |
1531 | debug2("channel %d: not open", c->self); | |
1532 | chan_mark_dead(c); | |
1533 | return -1; | |
1534 | } else if (compat13) { | |
1535 | buffer_clear(&c->output); | |
1536 | debug2("channel %d: input draining.", c->self); | |
1537 | c->type = SSH_CHANNEL_INPUT_DRAINING; | |
1538 | } else { | |
1539 | chan_write_failed(c); | |
1540 | } | |
1541 | return -1; | |
1542 | } | |
1543 | if (compat20 && c->isatty && dlen >= 1 && buf[0] != '\r') { | |
1544 | if (tcgetattr(c->wfd, &tio) == 0 && | |
1545 | !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) { | |
1546 | /* | |
1547 | * Simulate echo to reduce the impact of | |
1548 | * traffic analysis. We need to match the | |
1549 | * size of a SSH2_MSG_CHANNEL_DATA message | |
1550 | * (4 byte channel id + buf) | |
1551 | */ | |
1552 | packet_send_ignore(4 + len); | |
1553 | packet_send(); | |
1554 | } | |
1555 | } | |
1556 | buffer_consume(&c->output, len); | |
1557 | if (compat20 && len > 0) { | |
1558 | c->local_consumed += len; | |
1559 | } | |
1560 | } | |
1561 | return 1; | |
1562 | } | |
1563 | ||
1564 | static int | |
1565 | channel_handle_efd(Channel *c, fd_set *readset, fd_set *writeset) | |
1566 | { | |
1567 | char buf[CHAN_RBUF]; | |
1568 | int len; | |
1569 | ||
1570 | /** XXX handle drain efd, too */ | |
1571 | if (c->efd != -1) { | |
1572 | if (c->extended_usage == CHAN_EXTENDED_WRITE && | |
1573 | FD_ISSET(c->efd, writeset) && | |
1574 | buffer_len(&c->extended) > 0) { | |
1575 | len = write(c->efd, buffer_ptr(&c->extended), | |
1576 | buffer_len(&c->extended)); | |
1577 | debug2("channel %d: written %d to efd %d", | |
1578 | c->self, len, c->efd); | |
1579 | if (len < 0 && (errno == EINTR || errno == EAGAIN)) | |
1580 | return 1; | |
1581 | if (len <= 0) { | |
1582 | debug2("channel %d: closing write-efd %d", | |
1583 | c->self, c->efd); | |
1584 | channel_close_fd(&c->efd); | |
1585 | } else { | |
1586 | buffer_consume(&c->extended, len); | |
1587 | c->local_consumed += len; | |
1588 | } | |
1589 | } else if (c->extended_usage == CHAN_EXTENDED_READ && | |
1590 | FD_ISSET(c->efd, readset)) { | |
1591 | len = read(c->efd, buf, sizeof(buf)); | |
1592 | debug2("channel %d: read %d from efd %d", | |
1593 | c->self, len, c->efd); | |
1594 | if (len < 0 && (errno == EINTR || errno == EAGAIN)) | |
1595 | return 1; | |
1596 | if (len <= 0) { | |
1597 | debug2("channel %d: closing read-efd %d", | |
1598 | c->self, c->efd); | |
1599 | channel_close_fd(&c->efd); | |
1600 | } else { | |
1601 | buffer_append(&c->extended, buf, len); | |
1602 | } | |
1603 | } | |
1604 | } | |
1605 | return 1; | |
1606 | } | |
1607 | ||
1608 | static int | |
1609 | channel_handle_ctl(Channel *c, fd_set *readset, fd_set *writeset) | |
1610 | { | |
1611 | char buf[16]; | |
1612 | int len; | |
1613 | ||
1614 | /* Monitor control fd to detect if the slave client exits */ | |
1615 | if (c->ctl_fd != -1 && FD_ISSET(c->ctl_fd, readset)) { | |
1616 | len = read(c->ctl_fd, buf, sizeof(buf)); | |
1617 | if (len < 0 && (errno == EINTR || errno == EAGAIN)) | |
1618 | return 1; | |
1619 | if (len <= 0) { | |
1620 | debug2("channel %d: ctl read<=0", c->self); | |
1621 | if (c->type != SSH_CHANNEL_OPEN) { | |
1622 | debug2("channel %d: not open", c->self); | |
1623 | chan_mark_dead(c); | |
1624 | return -1; | |
1625 | } else { | |
1626 | chan_read_failed(c); | |
1627 | chan_write_failed(c); | |
1628 | } | |
1629 | return -1; | |
1630 | } else | |
1631 | fatal("%s: unexpected data on ctl fd", __func__); | |
1632 | } | |
1633 | return 1; | |
1634 | } | |
1635 | ||
1636 | static int | |
1637 | channel_check_window(Channel *c) | |
1638 | { | |
1639 | if (c->type == SSH_CHANNEL_OPEN && | |
1640 | !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) && | |
1641 | c->local_window < c->local_window_max/2 && | |
1642 | c->local_consumed > 0) { | |
1643 | packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST); | |
1644 | packet_put_int(c->remote_id); | |
1645 | packet_put_int(c->local_consumed); | |
1646 | packet_send(); | |
1647 | debug2("channel %d: window %d sent adjust %d", | |
1648 | c->self, c->local_window, | |
1649 | c->local_consumed); | |
1650 | c->local_window += c->local_consumed; | |
1651 | c->local_consumed = 0; | |
1652 | } | |
1653 | return 1; | |
1654 | } | |
1655 | ||
1656 | static void | |
1657 | channel_post_open(Channel *c, fd_set *readset, fd_set *writeset) | |
1658 | { | |
1659 | if (c->delayed) | |
1660 | return; | |
1661 | channel_handle_rfd(c, readset, writeset); | |
1662 | channel_handle_wfd(c, readset, writeset); | |
1663 | if (!compat20) | |
1664 | return; | |
1665 | channel_handle_efd(c, readset, writeset); | |
1666 | channel_handle_ctl(c, readset, writeset); | |
1667 | channel_check_window(c); | |
1668 | } | |
1669 | ||
1670 | static void | |
1671 | channel_post_output_drain_13(Channel *c, fd_set *readset, fd_set *writeset) | |
1672 | { | |
1673 | int len; | |
1674 | ||
1675 | /* Send buffered output data to the socket. */ | |
1676 | if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) { | |
1677 | len = write(c->sock, buffer_ptr(&c->output), | |
1678 | buffer_len(&c->output)); | |
1679 | if (len <= 0) | |
1680 | buffer_clear(&c->output); | |
1681 | else | |
1682 | buffer_consume(&c->output, len); | |
1683 | } | |
1684 | } | |
1685 | ||
1686 | static void | |
1687 | channel_handler_init_20(void) | |
1688 | { | |
1689 | channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open; | |
1690 | channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; | |
1691 | channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; | |
1692 | channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener; | |
1693 | channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; | |
1694 | channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; | |
1695 | channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; | |
1696 | channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; | |
1697 | ||
1698 | channel_post[SSH_CHANNEL_OPEN] = &channel_post_open; | |
1699 | channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; | |
1700 | channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener; | |
1701 | channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; | |
1702 | channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; | |
1703 | channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; | |
1704 | channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; | |
1705 | } | |
1706 | ||
1707 | static void | |
1708 | channel_handler_init_13(void) | |
1709 | { | |
1710 | channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13; | |
1711 | channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13; | |
1712 | channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; | |
1713 | channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; | |
1714 | channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; | |
1715 | channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining; | |
1716 | channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining; | |
1717 | channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; | |
1718 | channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; | |
1719 | ||
1720 | channel_post[SSH_CHANNEL_OPEN] = &channel_post_open; | |
1721 | channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; | |
1722 | channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; | |
1723 | channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; | |
1724 | channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13; | |
1725 | channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; | |
1726 | channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; | |
1727 | } | |
1728 | ||
1729 | static void | |
1730 | channel_handler_init_15(void) | |
1731 | { | |
1732 | channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open; | |
1733 | channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; | |
1734 | channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; | |
1735 | channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; | |
1736 | channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; | |
1737 | channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; | |
1738 | channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; | |
1739 | ||
1740 | channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; | |
1741 | channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; | |
1742 | channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; | |
1743 | channel_post[SSH_CHANNEL_OPEN] = &channel_post_open; | |
1744 | channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; | |
1745 | channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; | |
1746 | } | |
1747 | ||
1748 | static void | |
1749 | channel_handler_init(void) | |
1750 | { | |
1751 | int i; | |
1752 | ||
1753 | for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) { | |
1754 | channel_pre[i] = NULL; | |
1755 | channel_post[i] = NULL; | |
1756 | } | |
1757 | if (compat20) | |
1758 | channel_handler_init_20(); | |
1759 | else if (compat13) | |
1760 | channel_handler_init_13(); | |
1761 | else | |
1762 | channel_handler_init_15(); | |
1763 | } | |
1764 | ||
1765 | /* gc dead channels */ | |
1766 | static void | |
1767 | channel_garbage_collect(Channel *c) | |
1768 | { | |
1769 | if (c == NULL) | |
1770 | return; | |
1771 | if (c->detach_user != NULL) { | |
1772 | if (!chan_is_dead(c, c->detach_close)) | |
1773 | return; | |
1774 | debug2("channel %d: gc: notify user", c->self); | |
1775 | c->detach_user(c->self, NULL); | |
1776 | /* if we still have a callback */ | |
1777 | if (c->detach_user != NULL) | |
1778 | return; | |
1779 | debug2("channel %d: gc: user detached", c->self); | |
1780 | } | |
1781 | if (!chan_is_dead(c, 1)) | |
1782 | return; | |
1783 | debug2("channel %d: garbage collecting", c->self); | |
1784 | channel_free(c); | |
1785 | } | |
1786 | ||
1787 | static void | |
1788 | channel_handler(chan_fn *ftab[], fd_set *readset, fd_set *writeset) | |
1789 | { | |
1790 | static int did_init = 0; | |
1791 | u_int i; | |
1792 | Channel *c; | |
1793 | ||
1794 | if (!did_init) { | |
1795 | channel_handler_init(); | |
1796 | did_init = 1; | |
1797 | } | |
1798 | for (i = 0; i < channels_alloc; i++) { | |
1799 | c = channels[i]; | |
1800 | if (c == NULL) | |
1801 | continue; | |
1802 | if (ftab[c->type] != NULL) | |
1803 | (*ftab[c->type])(c, readset, writeset); | |
1804 | channel_garbage_collect(c); | |
1805 | } | |
1806 | } | |
1807 | ||
1808 | /* | |
1809 | * Allocate/update select bitmasks and add any bits relevant to channels in | |
1810 | * select bitmasks. | |
1811 | */ | |
1812 | void | |
1813 | channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp, | |
1814 | u_int *nallocp, int rekeying) | |
1815 | { | |
1816 | u_int n, sz, nfdset; | |
1817 | ||
1818 | n = MAX(*maxfdp, channel_max_fd); | |
1819 | ||
1820 | nfdset = howmany(n+1, NFDBITS); | |
1821 | /* Explicitly test here, because xrealloc isn't always called */ | |
1822 | if (nfdset && SIZE_T_MAX / nfdset < sizeof(fd_mask)) | |
1823 | fatal("channel_prepare_select: max_fd (%d) is too large", n); | |
1824 | sz = nfdset * sizeof(fd_mask); | |
1825 | ||
1826 | /* perhaps check sz < nalloc/2 and shrink? */ | |
1827 | if (*readsetp == NULL || sz > *nallocp) { | |
1828 | *readsetp = xrealloc(*readsetp, nfdset, sizeof(fd_mask)); | |
1829 | *writesetp = xrealloc(*writesetp, nfdset, sizeof(fd_mask)); | |
1830 | *nallocp = sz; | |
1831 | } | |
1832 | *maxfdp = n; | |
1833 | memset(*readsetp, 0, sz); | |
1834 | memset(*writesetp, 0, sz); | |
1835 | ||
1836 | if (!rekeying) | |
1837 | channel_handler(channel_pre, *readsetp, *writesetp); | |
1838 | } | |
1839 | ||
1840 | /* | |
1841 | * After select, perform any appropriate operations for channels which have | |
1842 | * events pending. | |
1843 | */ | |
1844 | void | |
1845 | channel_after_select(fd_set *readset, fd_set *writeset) | |
1846 | { | |
1847 | channel_handler(channel_post, readset, writeset); | |
1848 | } | |
1849 | ||
1850 | ||
1851 | /* If there is data to send to the connection, enqueue some of it now. */ | |
1852 | void | |
1853 | channel_output_poll(void) | |
1854 | { | |
1855 | Channel *c; | |
1856 | u_int i, len; | |
1857 | ||
1858 | for (i = 0; i < channels_alloc; i++) { | |
1859 | c = channels[i]; | |
1860 | if (c == NULL) | |
1861 | continue; | |
1862 | ||
1863 | /* | |
1864 | * We are only interested in channels that can have buffered | |
1865 | * incoming data. | |
1866 | */ | |
1867 | if (compat13) { | |
1868 | if (c->type != SSH_CHANNEL_OPEN && | |
1869 | c->type != SSH_CHANNEL_INPUT_DRAINING) | |
1870 | continue; | |
1871 | } else { | |
1872 | if (c->type != SSH_CHANNEL_OPEN) | |
1873 | continue; | |
1874 | } | |
1875 | if (compat20 && | |
1876 | (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) { | |
1877 | /* XXX is this true? */ | |
1878 | debug3("channel %d: will not send data after close", c->self); | |
1879 | continue; | |
1880 | } | |
1881 | ||
1882 | /* Get the amount of buffered data for this channel. */ | |
1883 | if ((c->istate == CHAN_INPUT_OPEN || | |
1884 | c->istate == CHAN_INPUT_WAIT_DRAIN) && | |
1885 | (len = buffer_len(&c->input)) > 0) { | |
1886 | if (c->datagram) { | |
1887 | if (len > 0) { | |
1888 | u_char *data; | |
1889 | u_int dlen; | |
1890 | ||
1891 | data = buffer_get_string(&c->input, | |
1892 | &dlen); | |
1893 | packet_start(SSH2_MSG_CHANNEL_DATA); | |
1894 | packet_put_int(c->remote_id); | |
1895 | packet_put_string(data, dlen); | |
1896 | packet_send(); | |
1897 | c->remote_window -= dlen + 4; | |
1898 | xfree(data); | |
1899 | } | |
1900 | continue; | |
1901 | } | |
1902 | /* | |
1903 | * Send some data for the other side over the secure | |
1904 | * connection. | |
1905 | */ | |
1906 | if (compat20) { | |
1907 | if (len > c->remote_window) | |
1908 | len = c->remote_window; | |
1909 | if (len > c->remote_maxpacket) | |
1910 | len = c->remote_maxpacket; | |
1911 | } else { | |
1912 | if (packet_is_interactive()) { | |
1913 | if (len > 1024) | |
1914 | len = 512; | |
1915 | } else { | |
1916 | /* Keep the packets at reasonable size. */ | |
1917 | if (len > packet_get_maxsize()/2) | |
1918 | len = packet_get_maxsize()/2; | |
1919 | } | |
1920 | } | |
1921 | if (len > 0) { | |
1922 | packet_start(compat20 ? | |
1923 | SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA); | |
1924 | packet_put_int(c->remote_id); | |
1925 | packet_put_string(buffer_ptr(&c->input), len); | |
1926 | packet_send(); | |
1927 | buffer_consume(&c->input, len); | |
1928 | c->remote_window -= len; | |
1929 | } | |
1930 | } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) { | |
1931 | if (compat13) | |
1932 | fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3"); | |
1933 | /* | |
1934 | * input-buffer is empty and read-socket shutdown: | |
1935 | * tell peer, that we will not send more data: send IEOF. | |
1936 | * hack for extended data: delay EOF if EFD still in use. | |
1937 | */ | |
1938 | if (CHANNEL_EFD_INPUT_ACTIVE(c)) | |
1939 | debug2("channel %d: ibuf_empty delayed efd %d/(%d)", | |
1940 | c->self, c->efd, buffer_len(&c->extended)); | |
1941 | else | |
1942 | chan_ibuf_empty(c); | |
1943 | } | |
1944 | /* Send extended data, i.e. stderr */ | |
1945 | if (compat20 && | |
1946 | !(c->flags & CHAN_EOF_SENT) && | |
1947 | c->remote_window > 0 && | |
1948 | (len = buffer_len(&c->extended)) > 0 && | |
1949 | c->extended_usage == CHAN_EXTENDED_READ) { | |
1950 | debug2("channel %d: rwin %u elen %u euse %d", | |
1951 | c->self, c->remote_window, buffer_len(&c->extended), | |
1952 | c->extended_usage); | |
1953 | if (len > c->remote_window) | |
1954 | len = c->remote_window; | |
1955 | if (len > c->remote_maxpacket) | |
1956 | len = c->remote_maxpacket; | |
1957 | packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA); | |
1958 | packet_put_int(c->remote_id); | |
1959 | packet_put_int(SSH2_EXTENDED_DATA_STDERR); | |
1960 | packet_put_string(buffer_ptr(&c->extended), len); | |
1961 | packet_send(); | |
1962 | buffer_consume(&c->extended, len); | |
1963 | c->remote_window -= len; | |
1964 | debug2("channel %d: sent ext data %d", c->self, len); | |
1965 | } | |
1966 | } | |
1967 | } | |
1968 | ||
1969 | ||
1970 | /* -- protocol input */ | |
1971 | ||
1972 | /* ARGSUSED */ | |
1973 | void | |
1974 | channel_input_data(int type, u_int32_t seq, void *ctxt) | |
1975 | { | |
1976 | int id; | |
1977 | char *data; | |
1978 | u_int data_len; | |
1979 | Channel *c; | |
1980 | ||
1981 | /* Get the channel number and verify it. */ | |
1982 | id = packet_get_int(); | |
1983 | c = channel_lookup(id); | |
1984 | if (c == NULL) | |
1985 | packet_disconnect("Received data for nonexistent channel %d.", id); | |
1986 | ||
1987 | /* Ignore any data for non-open channels (might happen on close) */ | |
1988 | if (c->type != SSH_CHANNEL_OPEN && | |
1989 | c->type != SSH_CHANNEL_X11_OPEN) | |
1990 | return; | |
1991 | ||
1992 | /* Get the data. */ | |
1993 | data = packet_get_string(&data_len); | |
1994 | ||
1995 | /* | |
1996 | * Ignore data for protocol > 1.3 if output end is no longer open. | |
1997 | * For protocol 2 the sending side is reducing its window as it sends | |
1998 | * data, so we must 'fake' consumption of the data in order to ensure | |
1999 | * that window updates are sent back. Otherwise the connection might | |
2000 | * deadlock. | |
2001 | */ | |
2002 | if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) { | |
2003 | if (compat20) { | |
2004 | c->local_window -= data_len; | |
2005 | c->local_consumed += data_len; | |
2006 | } | |
2007 | xfree(data); | |
2008 | return; | |
2009 | } | |
2010 | ||
2011 | if (compat20) { | |
2012 | if (data_len > c->local_maxpacket) { | |
2013 | logit("channel %d: rcvd big packet %d, maxpack %d", | |
2014 | c->self, data_len, c->local_maxpacket); | |
2015 | } | |
2016 | if (data_len > c->local_window) { | |
2017 | logit("channel %d: rcvd too much data %d, win %d", | |
2018 | c->self, data_len, c->local_window); | |
2019 | xfree(data); | |
2020 | return; | |
2021 | } | |
2022 | c->local_window -= data_len; | |
2023 | } | |
2024 | packet_check_eom(); | |
2025 | if (c->datagram) | |
2026 | buffer_put_string(&c->output, data, data_len); | |
2027 | else | |
2028 | buffer_append(&c->output, data, data_len); | |
2029 | xfree(data); | |
2030 | } | |
2031 | ||
2032 | /* ARGSUSED */ | |
2033 | void | |
2034 | channel_input_extended_data(int type, u_int32_t seq, void *ctxt) | |
2035 | { | |
2036 | int id; | |
2037 | char *data; | |
2038 | u_int data_len, tcode; | |
2039 | Channel *c; | |
2040 | ||
2041 | /* Get the channel number and verify it. */ | |
2042 | id = packet_get_int(); | |
2043 | c = channel_lookup(id); | |
2044 | ||
2045 | if (c == NULL) | |
2046 | packet_disconnect("Received extended_data for bad channel %d.", id); | |
2047 | if (c->type != SSH_CHANNEL_OPEN) { | |
2048 | logit("channel %d: ext data for non open", id); | |
2049 | return; | |
2050 | } | |
2051 | if (c->flags & CHAN_EOF_RCVD) { | |
2052 | if (datafellows & SSH_BUG_EXTEOF) | |
2053 | debug("channel %d: accepting ext data after eof", id); | |
2054 | else | |
2055 | packet_disconnect("Received extended_data after EOF " | |
2056 | "on channel %d.", id); | |
2057 | } | |
2058 | tcode = packet_get_int(); | |
2059 | if (c->efd == -1 || | |
2060 | c->extended_usage != CHAN_EXTENDED_WRITE || | |
2061 | tcode != SSH2_EXTENDED_DATA_STDERR) { | |
2062 | logit("channel %d: bad ext data", c->self); | |
2063 | return; | |
2064 | } | |
2065 | data = packet_get_string(&data_len); | |
2066 | packet_check_eom(); | |
2067 | if (data_len > c->local_window) { | |
2068 | logit("channel %d: rcvd too much extended_data %d, win %d", | |
2069 | c->self, data_len, c->local_window); | |
2070 | xfree(data); | |
2071 | return; | |
2072 | } | |
2073 | debug2("channel %d: rcvd ext data %d", c->self, data_len); | |
2074 | c->local_window -= data_len; | |
2075 | buffer_append(&c->extended, data, data_len); | |
2076 | xfree(data); | |
2077 | } | |
2078 | ||
2079 | /* ARGSUSED */ | |
2080 | void | |
2081 | channel_input_ieof(int type, u_int32_t seq, void *ctxt) | |
2082 | { | |
2083 | int id; | |
2084 | Channel *c; | |
2085 | ||
2086 | id = packet_get_int(); | |
2087 | packet_check_eom(); | |
2088 | c = channel_lookup(id); | |
2089 | if (c == NULL) | |
2090 | packet_disconnect("Received ieof for nonexistent channel %d.", id); | |
2091 | chan_rcvd_ieof(c); | |
2092 | ||
2093 | /* XXX force input close */ | |
2094 | if (c->force_drain && c->istate == CHAN_INPUT_OPEN) { | |
2095 | debug("channel %d: FORCE input drain", c->self); | |
2096 | c->istate = CHAN_INPUT_WAIT_DRAIN; | |
2097 | if (buffer_len(&c->input) == 0) | |
2098 | chan_ibuf_empty(c); | |
2099 | } | |
2100 | ||
2101 | } | |
2102 | ||
2103 | /* ARGSUSED */ | |
2104 | void | |
2105 | channel_input_close(int type, u_int32_t seq, void *ctxt) | |
2106 | { | |
2107 | int id; | |
2108 | Channel *c; | |
2109 | ||
2110 | id = packet_get_int(); | |
2111 | packet_check_eom(); | |
2112 | c = channel_lookup(id); | |
2113 | if (c == NULL) | |
2114 | packet_disconnect("Received close for nonexistent channel %d.", id); | |
2115 | ||
2116 | /* | |
2117 | * Send a confirmation that we have closed the channel and no more | |
2118 | * data is coming for it. | |
2119 | */ | |
2120 | packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION); | |
2121 | packet_put_int(c->remote_id); | |
2122 | packet_send(); | |
2123 | ||
2124 | /* | |
2125 | * If the channel is in closed state, we have sent a close request, | |
2126 | * and the other side will eventually respond with a confirmation. | |
2127 | * Thus, we cannot free the channel here, because then there would be | |
2128 | * no-one to receive the confirmation. The channel gets freed when | |
2129 | * the confirmation arrives. | |
2130 | */ | |
2131 | if (c->type != SSH_CHANNEL_CLOSED) { | |
2132 | /* | |
2133 | * Not a closed channel - mark it as draining, which will | |
2134 | * cause it to be freed later. | |
2135 | */ | |
2136 | buffer_clear(&c->input); | |
2137 | c->type = SSH_CHANNEL_OUTPUT_DRAINING; | |
2138 | } | |
2139 | } | |
2140 | ||
2141 | /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */ | |
2142 | /* ARGSUSED */ | |
2143 | void | |
2144 | channel_input_oclose(int type, u_int32_t seq, void *ctxt) | |
2145 | { | |
2146 | int id = packet_get_int(); | |
2147 | Channel *c = channel_lookup(id); | |
2148 | ||
2149 | packet_check_eom(); | |
2150 | if (c == NULL) | |
2151 | packet_disconnect("Received oclose for nonexistent channel %d.", id); | |
2152 | chan_rcvd_oclose(c); | |
2153 | } | |
2154 | ||
2155 | /* ARGSUSED */ | |
2156 | void | |
2157 | channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt) | |
2158 | { | |
2159 | int id = packet_get_int(); | |
2160 | Channel *c = channel_lookup(id); | |
2161 | ||
2162 | packet_check_eom(); | |
2163 | if (c == NULL) | |
2164 | packet_disconnect("Received close confirmation for " | |
2165 | "out-of-range channel %d.", id); | |
2166 | if (c->type != SSH_CHANNEL_CLOSED) | |
2167 | packet_disconnect("Received close confirmation for " | |
2168 | "non-closed channel %d (type %d).", id, c->type); | |
2169 | channel_free(c); | |
2170 | } | |
2171 | ||
2172 | /* ARGSUSED */ | |
2173 | void | |
2174 | channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt) | |
2175 | { | |
2176 | int id, remote_id; | |
2177 | Channel *c; | |
2178 | ||
2179 | id = packet_get_int(); | |
2180 | c = channel_lookup(id); | |
2181 | ||
2182 | if (c==NULL || c->type != SSH_CHANNEL_OPENING) | |
2183 | packet_disconnect("Received open confirmation for " | |
2184 | "non-opening channel %d.", id); | |
2185 | remote_id = packet_get_int(); | |
2186 | /* Record the remote channel number and mark that the channel is now open. */ | |
2187 | c->remote_id = remote_id; | |
2188 | c->type = SSH_CHANNEL_OPEN; | |
2189 | ||
2190 | if (compat20) { | |
2191 | c->remote_window = packet_get_int(); | |
2192 | c->remote_maxpacket = packet_get_int(); | |
2193 | if (c->confirm) { | |
2194 | debug2("callback start"); | |
2195 | c->confirm(c->self, c->confirm_ctx); | |
2196 | debug2("callback done"); | |
2197 | } | |
2198 | debug2("channel %d: open confirm rwindow %u rmax %u", c->self, | |
2199 | c->remote_window, c->remote_maxpacket); | |
2200 | } | |
2201 | packet_check_eom(); | |
2202 | } | |
2203 | ||
2204 | static char * | |
2205 | reason2txt(int reason) | |
2206 | { | |
2207 | switch (reason) { | |
2208 | case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED: | |
2209 | return "administratively prohibited"; | |
2210 | case SSH2_OPEN_CONNECT_FAILED: | |
2211 | return "connect failed"; | |
2212 | case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE: | |
2213 | return "unknown channel type"; | |
2214 | case SSH2_OPEN_RESOURCE_SHORTAGE: | |
2215 | return "resource shortage"; | |
2216 | } | |
2217 | return "unknown reason"; | |
2218 | } | |
2219 | ||
2220 | /* ARGSUSED */ | |
2221 | void | |
2222 | channel_input_open_failure(int type, u_int32_t seq, void *ctxt) | |
2223 | { | |
2224 | int id, reason; | |
2225 | char *msg = NULL, *lang = NULL; | |
2226 | Channel *c; | |
2227 | ||
2228 | id = packet_get_int(); | |
2229 | c = channel_lookup(id); | |
2230 | ||
2231 | if (c==NULL || c->type != SSH_CHANNEL_OPENING) | |
2232 | packet_disconnect("Received open failure for " | |
2233 | "non-opening channel %d.", id); | |
2234 | if (compat20) { | |
2235 | reason = packet_get_int(); | |
2236 | if (!(datafellows & SSH_BUG_OPENFAILURE)) { | |
2237 | msg = packet_get_string(NULL); | |
2238 | lang = packet_get_string(NULL); | |
2239 | } | |
2240 | logit("channel %d: open failed: %s%s%s", id, | |
2241 | reason2txt(reason), msg ? ": ": "", msg ? msg : ""); | |
2242 | if (msg != NULL) | |
2243 | xfree(msg); | |
2244 | if (lang != NULL) | |
2245 | xfree(lang); | |
2246 | } | |
2247 | packet_check_eom(); | |
2248 | /* Free the channel. This will also close the socket. */ | |
2249 | channel_free(c); | |
2250 | } | |
2251 | ||
2252 | /* ARGSUSED */ | |
2253 | void | |
2254 | channel_input_window_adjust(int type, u_int32_t seq, void *ctxt) | |
2255 | { | |
2256 | Channel *c; | |
2257 | int id; | |
2258 | u_int adjust; | |
2259 | ||
2260 | if (!compat20) | |
2261 | return; | |
2262 | ||
2263 | /* Get the channel number and verify it. */ | |
2264 | id = packet_get_int(); | |
2265 | c = channel_lookup(id); | |
2266 | ||
2267 | if (c == NULL) { | |
2268 | logit("Received window adjust for non-open channel %d.", id); | |
2269 | return; | |
2270 | } | |
2271 | adjust = packet_get_int(); | |
2272 | packet_check_eom(); | |
2273 | debug2("channel %d: rcvd adjust %u", id, adjust); | |
2274 | c->remote_window += adjust; | |
2275 | } | |
2276 | ||
2277 | /* ARGSUSED */ | |
2278 | void | |
2279 | channel_input_port_open(int type, u_int32_t seq, void *ctxt) | |
2280 | { | |
2281 | Channel *c = NULL; | |
2282 | u_short host_port; | |
2283 | char *host, *originator_string; | |
2284 | int remote_id, sock = -1; | |
2285 | ||
2286 | remote_id = packet_get_int(); | |
2287 | host = packet_get_string(NULL); | |
2288 | host_port = packet_get_int(); | |
2289 | ||
2290 | if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) { | |
2291 | originator_string = packet_get_string(NULL); | |
2292 | } else { | |
2293 | originator_string = xstrdup("unknown (remote did not supply name)"); | |
2294 | } | |
2295 | packet_check_eom(); | |
2296 | sock = channel_connect_to(host, host_port); | |
2297 | if (sock != -1) { | |
2298 | c = channel_new("connected socket", | |
2299 | SSH_CHANNEL_CONNECTING, sock, sock, -1, 0, 0, 0, | |
2300 | originator_string, 1); | |
2301 | c->remote_id = remote_id; | |
2302 | } | |
2303 | xfree(originator_string); | |
2304 | if (c == NULL) { | |
2305 | packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); | |
2306 | packet_put_int(remote_id); | |
2307 | packet_send(); | |
2308 | } | |
2309 | xfree(host); | |
2310 | } | |
2311 | ||
2312 | ||
2313 | /* -- tcp forwarding */ | |
2314 | ||
2315 | void | |
2316 | channel_set_af(int af) | |
2317 | { | |
2318 | IPv4or6 = af; | |
2319 | } | |
2320 | ||
2321 | static int | |
2322 | channel_setup_fwd_listener(int type, const char *listen_addr, u_short listen_port, | |
2323 | const char *host_to_connect, u_short port_to_connect, int gateway_ports) | |
2324 | { | |
2325 | Channel *c; | |
2326 | int sock, r, success = 0, wildcard = 0, is_client; | |
2327 | struct addrinfo hints, *ai, *aitop; | |
2328 | const char *host, *addr; | |
2329 | char ntop[NI_MAXHOST], strport[NI_MAXSERV]; | |
2330 | ||
2331 | host = (type == SSH_CHANNEL_RPORT_LISTENER) ? | |
2332 | listen_addr : host_to_connect; | |
2333 | is_client = (type == SSH_CHANNEL_PORT_LISTENER); | |
2334 | ||
2335 | if (host == NULL) { | |
2336 | error("No forward host name."); | |
2337 | return 0; | |
2338 | } | |
2339 | if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) { | |
2340 | error("Forward host name too long."); | |
2341 | return 0; | |
2342 | } | |
2343 | ||
2344 | /* | |
2345 | * Determine whether or not a port forward listens to loopback, | |
2346 | * specified address or wildcard. On the client, a specified bind | |
2347 | * address will always override gateway_ports. On the server, a | |
2348 | * gateway_ports of 1 (``yes'') will override the client's | |
2349 | * specification and force a wildcard bind, whereas a value of 2 | |
2350 | * (``clientspecified'') will bind to whatever address the client | |
2351 | * asked for. | |
2352 | * | |
2353 | * Special-case listen_addrs are: | |
2354 | * | |
2355 | * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR | |
2356 | * "" (empty string), "*" -> wildcard v4/v6 | |
2357 | * "localhost" -> loopback v4/v6 | |
2358 | */ | |
2359 | addr = NULL; | |
2360 | if (listen_addr == NULL) { | |
2361 | /* No address specified: default to gateway_ports setting */ | |
2362 | if (gateway_ports) | |
2363 | wildcard = 1; | |
2364 | } else if (gateway_ports || is_client) { | |
2365 | if (((datafellows & SSH_OLD_FORWARD_ADDR) && | |
2366 | strcmp(listen_addr, "0.0.0.0") == 0) || | |
2367 | *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 || | |
2368 | (!is_client && gateway_ports == 1)) | |
2369 | wildcard = 1; | |
2370 | else if (strcmp(listen_addr, "localhost") != 0) | |
2371 | addr = listen_addr; | |
2372 | } | |
2373 | ||
2374 | debug3("channel_setup_fwd_listener: type %d wildcard %d addr %s", | |
2375 | type, wildcard, (addr == NULL) ? "NULL" : addr); | |
2376 | ||
2377 | /* | |
2378 | * getaddrinfo returns a loopback address if the hostname is | |
2379 | * set to NULL and hints.ai_flags is not AI_PASSIVE | |
2380 | */ | |
2381 | memset(&hints, 0, sizeof(hints)); | |
2382 | hints.ai_family = IPv4or6; | |
2383 | hints.ai_flags = wildcard ? AI_PASSIVE : 0; | |
2384 | hints.ai_socktype = SOCK_STREAM; | |
2385 | snprintf(strport, sizeof strport, "%d", listen_port); | |
2386 | if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) { | |
2387 | if (addr == NULL) { | |
2388 | /* This really shouldn't happen */ | |
2389 | packet_disconnect("getaddrinfo: fatal error: %s", | |
2390 | gai_strerror(r)); | |
2391 | } else { | |
2392 | error("channel_setup_fwd_listener: " | |
2393 | "getaddrinfo(%.64s): %s", addr, gai_strerror(r)); | |
2394 | } | |
2395 | return 0; | |
2396 | } | |
2397 | ||
2398 | for (ai = aitop; ai; ai = ai->ai_next) { | |
2399 | if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) | |
2400 | continue; | |
2401 | if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), | |
2402 | strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) { | |
2403 | error("channel_setup_fwd_listener: getnameinfo failed"); | |
2404 | continue; | |
2405 | } | |
2406 | /* Create a port to listen for the host. */ | |
2407 | sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); | |
2408 | if (sock < 0) { | |
2409 | /* this is no error since kernel may not support ipv6 */ | |
2410 | verbose("socket: %.100s", strerror(errno)); | |
2411 | continue; | |
2412 | } | |
2413 | ||
2414 | channel_set_reuseaddr(sock); | |
2415 | ||
2416 | debug("Local forwarding listening on %s port %s.", ntop, strport); | |
2417 | ||
2418 | /* Bind the socket to the address. */ | |
2419 | if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) { | |
2420 | /* address can be in use ipv6 address is already bound */ | |
2421 | if (!ai->ai_next) | |
2422 | error("bind: %.100s", strerror(errno)); | |
2423 | else | |
2424 | verbose("bind: %.100s", strerror(errno)); | |
2425 | ||
2426 | close(sock); | |
2427 | continue; | |
2428 | } | |
2429 | /* Start listening for connections on the socket. */ | |
2430 | if (listen(sock, SSH_LISTEN_BACKLOG) < 0) { | |
2431 | error("listen: %.100s", strerror(errno)); | |
2432 | close(sock); | |
2433 | continue; | |
2434 | } | |
2435 | /* Allocate a channel number for the socket. */ | |
2436 | c = channel_new("port listener", type, sock, sock, -1, | |
2437 | CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, | |
2438 | 0, "port listener", 1); | |
2439 | strlcpy(c->path, host, sizeof(c->path)); | |
2440 | c->host_port = port_to_connect; | |
2441 | c->listening_port = listen_port; | |
2442 | success = 1; | |
2443 | } | |
2444 | if (success == 0) | |
2445 | error("channel_setup_fwd_listener: cannot listen to port: %d", | |
2446 | listen_port); | |
2447 | freeaddrinfo(aitop); | |
2448 | return success; | |
2449 | } | |
2450 | ||
2451 | int | |
2452 | channel_cancel_rport_listener(const char *host, u_short port) | |
2453 | { | |
2454 | u_int i; | |
2455 | int found = 0; | |
2456 | ||
2457 | for (i = 0; i < channels_alloc; i++) { | |
2458 | Channel *c = channels[i]; | |
2459 | ||
2460 | if (c != NULL && c->type == SSH_CHANNEL_RPORT_LISTENER && | |
2461 | strncmp(c->path, host, sizeof(c->path)) == 0 && | |
2462 | c->listening_port == port) { | |
2463 | debug2("%s: close channel %d", __func__, i); | |
2464 | channel_free(c); | |
2465 | found = 1; | |
2466 | } | |
2467 | } | |
2468 | ||
2469 | return (found); | |
2470 | } | |
2471 | ||
2472 | /* protocol local port fwd, used by ssh (and sshd in v1) */ | |
2473 | int | |
2474 | channel_setup_local_fwd_listener(const char *listen_host, u_short listen_port, | |
2475 | const char *host_to_connect, u_short port_to_connect, int gateway_ports) | |
2476 | { | |
2477 | return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER, | |
2478 | listen_host, listen_port, host_to_connect, port_to_connect, | |
2479 | gateway_ports); | |
2480 | } | |
2481 | ||
2482 | /* protocol v2 remote port fwd, used by sshd */ | |
2483 | int | |
2484 | channel_setup_remote_fwd_listener(const char *listen_address, | |
2485 | u_short listen_port, int gateway_ports) | |
2486 | { | |
2487 | return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER, | |
2488 | listen_address, listen_port, NULL, 0, gateway_ports); | |
2489 | } | |
2490 | ||
2491 | /* | |
2492 | * Initiate forwarding of connections to port "port" on remote host through | |
2493 | * the secure channel to host:port from local side. | |
2494 | */ | |
2495 | ||
2496 | int | |
2497 | channel_request_remote_forwarding(const char *listen_host, u_short listen_port, | |
2498 | const char *host_to_connect, u_short port_to_connect) | |
2499 | { | |
2500 | int type, success = 0; | |
2501 | ||
2502 | /* Record locally that connection to this host/port is permitted. */ | |
2503 | if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION) | |
2504 | fatal("channel_request_remote_forwarding: too many forwards"); | |
2505 | ||
2506 | /* Send the forward request to the remote side. */ | |
2507 | if (compat20) { | |
2508 | const char *address_to_bind; | |
2509 | if (listen_host == NULL) | |
2510 | address_to_bind = "localhost"; | |
2511 | else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0) | |
2512 | address_to_bind = ""; | |
2513 | else | |
2514 | address_to_bind = listen_host; | |
2515 | ||
2516 | packet_start(SSH2_MSG_GLOBAL_REQUEST); | |
2517 | packet_put_cstring("tcpip-forward"); | |
2518 | packet_put_char(1); /* boolean: want reply */ | |
2519 | packet_put_cstring(address_to_bind); | |
2520 | packet_put_int(listen_port); | |
2521 | packet_send(); | |
2522 | packet_write_wait(); | |
2523 | /* Assume that server accepts the request */ | |
2524 | success = 1; | |
2525 | } else { | |
2526 | packet_start(SSH_CMSG_PORT_FORWARD_REQUEST); | |
2527 | packet_put_int(listen_port); | |
2528 | packet_put_cstring(host_to_connect); | |
2529 | packet_put_int(port_to_connect); | |
2530 | packet_send(); | |
2531 | packet_write_wait(); | |
2532 | ||
2533 | /* Wait for response from the remote side. */ | |
2534 | type = packet_read(); | |
2535 | switch (type) { | |
2536 | case SSH_SMSG_SUCCESS: | |
2537 | success = 1; | |
2538 | break; | |
2539 | case SSH_SMSG_FAILURE: | |
2540 | break; | |
2541 | default: | |
2542 | /* Unknown packet */ | |
2543 | packet_disconnect("Protocol error for port forward request:" | |
2544 | "received packet type %d.", type); | |
2545 | } | |
2546 | } | |
2547 | if (success) { | |
2548 | permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect); | |
2549 | permitted_opens[num_permitted_opens].port_to_connect = port_to_connect; | |
2550 | permitted_opens[num_permitted_opens].listen_port = listen_port; | |
2551 | num_permitted_opens++; | |
2552 | } | |
2553 | return (success ? 0 : -1); | |
2554 | } | |
2555 | ||
2556 | /* | |
2557 | * Request cancellation of remote forwarding of connection host:port from | |
2558 | * local side. | |
2559 | */ | |
2560 | void | |
2561 | channel_request_rforward_cancel(const char *host, u_short port) | |
2562 | { | |
2563 | int i; | |
2564 | ||
2565 | if (!compat20) | |
2566 | return; | |
2567 | ||
2568 | for (i = 0; i < num_permitted_opens; i++) { | |
2569 | if (permitted_opens[i].host_to_connect != NULL && | |
2570 | permitted_opens[i].listen_port == port) | |
2571 | break; | |
2572 | } | |
2573 | if (i >= num_permitted_opens) { | |
2574 | debug("%s: requested forward not found", __func__); | |
2575 | return; | |
2576 | } | |
2577 | packet_start(SSH2_MSG_GLOBAL_REQUEST); | |
2578 | packet_put_cstring("cancel-tcpip-forward"); | |
2579 | packet_put_char(0); | |
2580 | packet_put_cstring(host == NULL ? "" : host); | |
2581 | packet_put_int(port); | |
2582 | packet_send(); | |
2583 | ||
2584 | permitted_opens[i].listen_port = 0; | |
2585 | permitted_opens[i].port_to_connect = 0; | |
2586 | xfree(permitted_opens[i].host_to_connect); | |
2587 | permitted_opens[i].host_to_connect = NULL; | |
2588 | } | |
2589 | ||
2590 | /* | |
2591 | * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates | |
2592 | * listening for the port, and sends back a success reply (or disconnect | |
2593 | * message if there was an error). | |
2594 | */ | |
2595 | int | |
2596 | channel_input_port_forward_request(int is_root, int gateway_ports) | |
2597 | { | |
2598 | u_short port, host_port; | |
2599 | int success = 0; | |
2600 | char *hostname; | |
2601 | ||
2602 | /* Get arguments from the packet. */ | |
2603 | port = packet_get_int(); | |
2604 | hostname = packet_get_string(NULL); | |
2605 | host_port = packet_get_int(); | |
2606 | ||
2607 | #ifndef HAVE_CYGWIN | |
2608 | /* | |
2609 | * Check that an unprivileged user is not trying to forward a | |
2610 | * privileged port. | |
2611 | */ | |
2612 | if (port < IPPORT_RESERVED && !is_root) | |
2613 | packet_disconnect( | |
2614 | "Requested forwarding of port %d but user is not root.", | |
2615 | port); | |
2616 | if (host_port == 0) | |
2617 | packet_disconnect("Dynamic forwarding denied."); | |
2618 | #endif | |
2619 | ||
2620 | /* Initiate forwarding */ | |
2621 | success = channel_setup_local_fwd_listener(NULL, port, hostname, | |
2622 | host_port, gateway_ports); | |
2623 | ||
2624 | /* Free the argument string. */ | |
2625 | xfree(hostname); | |
2626 | ||
2627 | return (success ? 0 : -1); | |
2628 | } | |
2629 | ||
2630 | /* | |
2631 | * Permits opening to any host/port if permitted_opens[] is empty. This is | |
2632 | * usually called by the server, because the user could connect to any port | |
2633 | * anyway, and the server has no way to know but to trust the client anyway. | |
2634 | */ | |
2635 | void | |
2636 | channel_permit_all_opens(void) | |
2637 | { | |
2638 | if (num_permitted_opens == 0) | |
2639 | all_opens_permitted = 1; | |
2640 | } | |
2641 | ||
2642 | void | |
2643 | channel_add_permitted_opens(char *host, int port) | |
2644 | { | |
2645 | if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION) | |
2646 | fatal("channel_add_permitted_opens: too many forwards"); | |
2647 | debug("allow port forwarding to host %s port %d", host, port); | |
2648 | ||
2649 | permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host); | |
2650 | permitted_opens[num_permitted_opens].port_to_connect = port; | |
2651 | num_permitted_opens++; | |
2652 | ||
2653 | all_opens_permitted = 0; | |
2654 | } | |
2655 | ||
2656 | void | |
2657 | channel_add_adm_permitted_opens(char *host, int port) | |
2658 | { | |
2659 | if (num_adm_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION) | |
2660 | fatal("channel_add_adm_permitted_opens: too many forwards"); | |
2661 | debug("allow port forwarding to host %s port %d", host, port); | |
2662 | ||
2663 | permitted_adm_opens[num_adm_permitted_opens].host_to_connect | |
2664 | = xstrdup(host); | |
2665 | permitted_adm_opens[num_adm_permitted_opens].port_to_connect = port; | |
2666 | num_adm_permitted_opens++; | |
2667 | } | |
2668 | ||
2669 | void | |
2670 | channel_clear_permitted_opens(void) | |
2671 | { | |
2672 | int i; | |
2673 | ||
2674 | for (i = 0; i < num_permitted_opens; i++) | |
2675 | if (permitted_opens[i].host_to_connect != NULL) | |
2676 | xfree(permitted_opens[i].host_to_connect); | |
2677 | num_permitted_opens = 0; | |
2678 | } | |
2679 | ||
2680 | void | |
2681 | channel_clear_adm_permitted_opens(void) | |
2682 | { | |
2683 | int i; | |
2684 | ||
2685 | for (i = 0; i < num_adm_permitted_opens; i++) | |
2686 | if (permitted_adm_opens[i].host_to_connect != NULL) | |
2687 | xfree(permitted_adm_opens[i].host_to_connect); | |
2688 | num_adm_permitted_opens = 0; | |
2689 | } | |
2690 | ||
2691 | /* return socket to remote host, port */ | |
2692 | static int | |
2693 | connect_to(const char *host, u_short port) | |
2694 | { | |
2695 | struct addrinfo hints, *ai, *aitop; | |
2696 | char ntop[NI_MAXHOST], strport[NI_MAXSERV]; | |
2697 | int gaierr; | |
2698 | int sock = -1; | |
2699 | ||
2700 | memset(&hints, 0, sizeof(hints)); | |
2701 | hints.ai_family = IPv4or6; | |
2702 | hints.ai_socktype = SOCK_STREAM; | |
2703 | snprintf(strport, sizeof strport, "%d", port); | |
2704 | if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) { | |
2705 | error("connect_to %.100s: unknown host (%s)", host, | |
2706 | gai_strerror(gaierr)); | |
2707 | return -1; | |
2708 | } | |
2709 | for (ai = aitop; ai; ai = ai->ai_next) { | |
2710 | if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) | |
2711 | continue; | |
2712 | if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), | |
2713 | strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) { | |
2714 | error("connect_to: getnameinfo failed"); | |
2715 | continue; | |
2716 | } | |
2717 | sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); | |
2718 | if (sock < 0) { | |
2719 | if (ai->ai_next == NULL) | |
2720 | error("socket: %.100s", strerror(errno)); | |
2721 | else | |
2722 | verbose("socket: %.100s", strerror(errno)); | |
2723 | continue; | |
2724 | } | |
2725 | if (set_nonblock(sock) == -1) | |
2726 | fatal("%s: set_nonblock(%d)", __func__, sock); | |
2727 | if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 && | |
2728 | errno != EINPROGRESS) { | |
2729 | error("connect_to %.100s port %s: %.100s", ntop, strport, | |
2730 | strerror(errno)); | |
2731 | close(sock); | |
2732 | continue; /* fail -- try next */ | |
2733 | } | |
2734 | break; /* success */ | |
2735 | ||
2736 | } | |
2737 | freeaddrinfo(aitop); | |
2738 | if (!ai) { | |
2739 | error("connect_to %.100s port %d: failed.", host, port); | |
2740 | return -1; | |
2741 | } | |
2742 | /* success */ | |
2743 | set_nodelay(sock); | |
2744 | return sock; | |
2745 | } | |
2746 | ||
2747 | int | |
2748 | channel_connect_by_listen_address(u_short listen_port) | |
2749 | { | |
2750 | int i; | |
2751 | ||
2752 | for (i = 0; i < num_permitted_opens; i++) | |
2753 | if (permitted_opens[i].host_to_connect != NULL && | |
2754 | permitted_opens[i].listen_port == listen_port) | |
2755 | return connect_to( | |
2756 | permitted_opens[i].host_to_connect, | |
2757 | permitted_opens[i].port_to_connect); | |
2758 | error("WARNING: Server requests forwarding for unknown listen_port %d", | |
2759 | listen_port); | |
2760 | return -1; | |
2761 | } | |
2762 | ||
2763 | /* Check if connecting to that port is permitted and connect. */ | |
2764 | int | |
2765 | channel_connect_to(const char *host, u_short port) | |
2766 | { | |
2767 | int i, permit, permit_adm = 1; | |
2768 | ||
2769 | permit = all_opens_permitted; | |
2770 | if (!permit) { | |
2771 | for (i = 0; i < num_permitted_opens; i++) | |
2772 | if (permitted_opens[i].host_to_connect != NULL && | |
2773 | permitted_opens[i].port_to_connect == port && | |
2774 | strcmp(permitted_opens[i].host_to_connect, host) == 0) | |
2775 | permit = 1; | |
2776 | } | |
2777 | ||
2778 | if (num_adm_permitted_opens > 0) { | |
2779 | permit_adm = 0; | |
2780 | for (i = 0; i < num_adm_permitted_opens; i++) | |
2781 | if (permitted_adm_opens[i].host_to_connect != NULL && | |
2782 | permitted_adm_opens[i].port_to_connect == port && | |
2783 | strcmp(permitted_adm_opens[i].host_to_connect, host) | |
2784 | == 0) | |
2785 | permit_adm = 1; | |
2786 | } | |
2787 | ||
2788 | if (!permit || !permit_adm) { | |
2789 | logit("Received request to connect to host %.100s port %d, " | |
2790 | "but the request was denied.", host, port); | |
2791 | return -1; | |
2792 | } | |
2793 | return connect_to(host, port); | |
2794 | } | |
2795 | ||
2796 | void | |
2797 | channel_send_window_changes(void) | |
2798 | { | |
2799 | u_int i; | |
2800 | struct winsize ws; | |
2801 | ||
2802 | for (i = 0; i < channels_alloc; i++) { | |
2803 | if (channels[i] == NULL || !channels[i]->client_tty || | |
2804 | channels[i]->type != SSH_CHANNEL_OPEN) | |
2805 | continue; | |
2806 | if (ioctl(channels[i]->rfd, TIOCGWINSZ, &ws) < 0) | |
2807 | continue; | |
2808 | channel_request_start(i, "window-change", 0); | |
2809 | packet_put_int((u_int)ws.ws_col); | |
2810 | packet_put_int((u_int)ws.ws_row); | |
2811 | packet_put_int((u_int)ws.ws_xpixel); | |
2812 | packet_put_int((u_int)ws.ws_ypixel); | |
2813 | packet_send(); | |
2814 | } | |
2815 | } | |
2816 | ||
2817 | /* -- X11 forwarding */ | |
2818 | ||
2819 | /* | |
2820 | * Creates an internet domain socket for listening for X11 connections. | |
2821 | * Returns 0 and a suitable display number for the DISPLAY variable | |
2822 | * stored in display_numberp , or -1 if an error occurs. | |
2823 | */ | |
2824 | int | |
2825 | x11_create_display_inet(int x11_display_offset, int x11_use_localhost, | |
2826 | int single_connection, u_int *display_numberp, int **chanids) | |
2827 | { | |
2828 | Channel *nc = NULL; | |
2829 | int display_number, sock; | |
2830 | u_short port; | |
2831 | struct addrinfo hints, *ai, *aitop; | |
2832 | char strport[NI_MAXSERV]; | |
2833 | int gaierr, n, num_socks = 0, socks[NUM_SOCKS]; | |
2834 | ||
2835 | if (chanids == NULL) | |
2836 | return -1; | |
2837 | ||
2838 | for (display_number = x11_display_offset; | |
2839 | display_number < MAX_DISPLAYS; | |
2840 | display_number++) { | |
2841 | port = 6000 + display_number; | |
2842 | memset(&hints, 0, sizeof(hints)); | |
2843 | hints.ai_family = IPv4or6; | |
2844 | hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE; | |
2845 | hints.ai_socktype = SOCK_STREAM; | |
2846 | snprintf(strport, sizeof strport, "%d", port); | |
2847 | if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) { | |
2848 | error("getaddrinfo: %.100s", gai_strerror(gaierr)); | |
2849 | return -1; | |
2850 | } | |
2851 | for (ai = aitop; ai; ai = ai->ai_next) { | |
2852 | if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) | |
2853 | continue; | |
2854 | sock = socket(ai->ai_family, ai->ai_socktype, | |
2855 | ai->ai_protocol); | |
2856 | if (sock < 0) { | |
2857 | if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) { | |
2858 | error("socket: %.100s", strerror(errno)); | |
2859 | freeaddrinfo(aitop); | |
2860 | return -1; | |
2861 | } else { | |
2862 | debug("x11_create_display_inet: Socket family %d not supported", | |
2863 | ai->ai_family); | |
2864 | continue; | |
2865 | } | |
2866 | } | |
2867 | #ifdef IPV6_V6ONLY | |
2868 | if (ai->ai_family == AF_INET6) { | |
2869 | int on = 1; | |
2870 | if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) < 0) | |
2871 | error("setsockopt IPV6_V6ONLY: %.100s", strerror(errno)); | |
2872 | } | |
2873 | #endif | |
2874 | channel_set_reuseaddr(sock); | |
2875 | if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) { | |
2876 | debug2("bind port %d: %.100s", port, strerror(errno)); | |
2877 | close(sock); | |
2878 | ||
2879 | if (ai->ai_next) | |
2880 | continue; | |
2881 | ||
2882 | for (n = 0; n < num_socks; n++) { | |
2883 | close(socks[n]); | |
2884 | } | |
2885 | num_socks = 0; | |
2886 | break; | |
2887 | } | |
2888 | socks[num_socks++] = sock; | |
2889 | #ifndef DONT_TRY_OTHER_AF | |
2890 | if (num_socks == NUM_SOCKS) | |
2891 | break; | |
2892 | #else | |
2893 | if (x11_use_localhost) { | |
2894 | if (num_socks == NUM_SOCKS) | |
2895 | break; | |
2896 | } else { | |
2897 | break; | |
2898 | } | |
2899 | #endif | |
2900 | } | |
2901 | freeaddrinfo(aitop); | |
2902 | if (num_socks > 0) | |
2903 | break; | |
2904 | } | |
2905 | if (display_number >= MAX_DISPLAYS) { | |
2906 | error("Failed to allocate internet-domain X11 display socket."); | |
2907 | return -1; | |
2908 | } | |
2909 | /* Start listening for connections on the socket. */ | |
2910 | for (n = 0; n < num_socks; n++) { | |
2911 | sock = socks[n]; | |
2912 | if (listen(sock, SSH_LISTEN_BACKLOG) < 0) { | |
2913 | error("listen: %.100s", strerror(errno)); | |
2914 | close(sock); | |
2915 | return -1; | |
2916 | } | |
2917 | } | |
2918 | ||
2919 | /* Allocate a channel for each socket. */ | |
2920 | *chanids = xcalloc(num_socks + 1, sizeof(**chanids)); | |
2921 | for (n = 0; n < num_socks; n++) { | |
2922 | sock = socks[n]; | |
2923 | nc = channel_new("x11 listener", | |
2924 | SSH_CHANNEL_X11_LISTENER, sock, sock, -1, | |
2925 | CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, | |
2926 | 0, "X11 inet listener", 1); | |
2927 | nc->single_connection = single_connection; | |
2928 | (*chanids)[n] = nc->self; | |
2929 | } | |
2930 | (*chanids)[n] = -1; | |
2931 | ||
2932 | /* Return the display number for the DISPLAY environment variable. */ | |
2933 | *display_numberp = display_number; | |
2934 | return (0); | |
2935 | } | |
2936 | ||
2937 | static int | |
2938 | connect_local_xsocket(u_int dnr) | |
2939 | { | |
2940 | int sock; | |
2941 | struct sockaddr_un addr; | |
2942 | ||
2943 | sock = socket(AF_UNIX, SOCK_STREAM, 0); | |
2944 | if (sock < 0) | |
2945 | error("socket: %.100s", strerror(errno)); | |
2946 | memset(&addr, 0, sizeof(addr)); | |
2947 | addr.sun_family = AF_UNIX; | |
2948 | snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr); | |
2949 | if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0) | |
2950 | return sock; | |
2951 | close(sock); | |
2952 | error("connect %.100s: %.100s", addr.sun_path, strerror(errno)); | |
2953 | return -1; | |
2954 | } | |
2955 | ||
2956 | int | |
2957 | x11_connect_display(void) | |
2958 | { | |
2959 | u_int display_number; | |
2960 | const char *display; | |
2961 | char buf[1024], *cp; | |
2962 | struct addrinfo hints, *ai, *aitop; | |
2963 | char strport[NI_MAXSERV]; | |
2964 | int gaierr, sock = 0; | |
2965 | ||
2966 | /* Try to open a socket for the local X server. */ | |
2967 | display = getenv("DISPLAY"); | |
2968 | if (!display) { | |
2969 | error("DISPLAY not set."); | |
2970 | return -1; | |
2971 | } | |
2972 | /* | |
2973 | * Now we decode the value of the DISPLAY variable and make a | |
2974 | * connection to the real X server. | |
2975 | */ | |
2976 | ||
2977 | /* | |
2978 | * Check if it is a unix domain socket. Unix domain displays are in | |
2979 | * one of the following formats: unix:d[.s], :d[.s], ::d[.s] | |
2980 | */ | |
2981 | if (strncmp(display, "unix:", 5) == 0 || | |
2982 | display[0] == ':') { | |
2983 | /* Connect to the unix domain socket. */ | |
2984 | if (sscanf(strrchr(display, ':') + 1, "%u", &display_number) != 1) { | |
2985 | error("Could not parse display number from DISPLAY: %.100s", | |
2986 | display); | |
2987 | return -1; | |
2988 | } | |
2989 | /* Create a socket. */ | |
2990 | sock = connect_local_xsocket(display_number); | |
2991 | if (sock < 0) | |
2992 | return -1; | |
2993 | ||
2994 | /* OK, we now have a connection to the display. */ | |
2995 | return sock; | |
2996 | } | |
2997 | /* | |
2998 | * Connect to an inet socket. The DISPLAY value is supposedly | |
2999 | * hostname:d[.s], where hostname may also be numeric IP address. | |
3000 | */ | |
3001 | strlcpy(buf, display, sizeof(buf)); | |
3002 | cp = strchr(buf, ':'); | |
3003 | if (!cp) { | |
3004 | error("Could not find ':' in DISPLAY: %.100s", display); | |
3005 | return -1; | |
3006 | } | |
3007 | *cp = 0; | |
3008 | /* buf now contains the host name. But first we parse the display number. */ | |
3009 | if (sscanf(cp + 1, "%u", &display_number) != 1) { | |
3010 | error("Could not parse display number from DISPLAY: %.100s", | |
3011 | display); | |
3012 | return -1; | |
3013 | } | |
3014 | ||
3015 | /* Look up the host address */ | |
3016 | memset(&hints, 0, sizeof(hints)); | |
3017 | hints.ai_family = IPv4or6; | |
3018 | hints.ai_socktype = SOCK_STREAM; | |
3019 | snprintf(strport, sizeof strport, "%u", 6000 + display_number); | |
3020 | if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) { | |
3021 | error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr)); | |
3022 | return -1; | |
3023 | } | |
3024 | for (ai = aitop; ai; ai = ai->ai_next) { | |
3025 | /* Create a socket. */ | |
3026 | sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); | |
3027 | if (sock < 0) { | |
3028 | debug2("socket: %.100s", strerror(errno)); | |
3029 | continue; | |
3030 | } | |
3031 | /* Connect it to the display. */ | |
3032 | if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) { | |
3033 | debug2("connect %.100s port %u: %.100s", buf, | |
3034 | 6000 + display_number, strerror(errno)); | |
3035 | close(sock); | |
3036 | continue; | |
3037 | } | |
3038 | /* Success */ | |
3039 | break; | |
3040 | } | |
3041 | freeaddrinfo(aitop); | |
3042 | if (!ai) { | |
3043 | error("connect %.100s port %u: %.100s", buf, 6000 + display_number, | |
3044 | strerror(errno)); | |
3045 | return -1; | |
3046 | } | |
3047 | set_nodelay(sock); | |
3048 | return sock; | |
3049 | } | |
3050 | ||
3051 | /* | |
3052 | * This is called when SSH_SMSG_X11_OPEN is received. The packet contains | |
3053 | * the remote channel number. We should do whatever we want, and respond | |
3054 | * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE. | |
3055 | */ | |
3056 | ||
3057 | void | |
3058 | x11_input_open(int type, u_int32_t seq, void *ctxt) | |
3059 | { | |
3060 | Channel *c = NULL; | |
3061 | int remote_id, sock = 0; | |
3062 | char *remote_host; | |
3063 | ||
3064 | debug("Received X11 open request."); | |
3065 | ||
3066 | remote_id = packet_get_int(); | |
3067 | ||
3068 | if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) { | |
3069 | remote_host = packet_get_string(NULL); | |
3070 | } else { | |
3071 | remote_host = xstrdup("unknown (remote did not supply name)"); | |
3072 | } | |
3073 | packet_check_eom(); | |
3074 | ||
3075 | /* Obtain a connection to the real X display. */ | |
3076 | sock = x11_connect_display(); | |
3077 | if (sock != -1) { | |
3078 | /* Allocate a channel for this connection. */ | |
3079 | c = channel_new("connected x11 socket", | |
3080 | SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0, | |
3081 | remote_host, 1); | |
3082 | c->remote_id = remote_id; | |
3083 | c->force_drain = 1; | |
3084 | } | |
3085 | xfree(remote_host); | |
3086 | if (c == NULL) { | |
3087 | /* Send refusal to the remote host. */ | |
3088 | packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); | |
3089 | packet_put_int(remote_id); | |
3090 | } else { | |
3091 | /* Send a confirmation to the remote host. */ | |
3092 | packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION); | |
3093 | packet_put_int(remote_id); | |
3094 | packet_put_int(c->self); | |
3095 | } | |
3096 | packet_send(); | |
3097 | } | |
3098 | ||
3099 | /* dummy protocol handler that denies SSH-1 requests (agent/x11) */ | |
3100 | void | |
3101 | deny_input_open(int type, u_int32_t seq, void *ctxt) | |
3102 | { | |
3103 | int rchan = packet_get_int(); | |
3104 | ||
3105 | switch (type) { | |
3106 | case SSH_SMSG_AGENT_OPEN: | |
3107 | error("Warning: ssh server tried agent forwarding."); | |
3108 | break; | |
3109 | case SSH_SMSG_X11_OPEN: | |
3110 | error("Warning: ssh server tried X11 forwarding."); | |
3111 | break; | |
3112 | default: | |
3113 | error("deny_input_open: type %d", type); | |
3114 | break; | |
3115 | } | |
3116 | error("Warning: this is probably a break-in attempt by a malicious server."); | |
3117 | packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); | |
3118 | packet_put_int(rchan); | |
3119 | packet_send(); | |
3120 | } | |
3121 | ||
3122 | /* | |
3123 | * Requests forwarding of X11 connections, generates fake authentication | |
3124 | * data, and enables authentication spoofing. | |
3125 | * This should be called in the client only. | |
3126 | */ | |
3127 | void | |
3128 | x11_request_forwarding_with_spoofing(int client_session_id, const char *disp, | |
3129 | const char *proto, const char *data) | |
3130 | { | |
3131 | u_int data_len = (u_int) strlen(data) / 2; | |
3132 | u_int i, value; | |
3133 | char *new_data; | |
3134 | int screen_number; | |
3135 | const char *cp; | |
3136 | u_int32_t rnd = 0; | |
3137 | ||
3138 | if (x11_saved_display == NULL) | |
3139 | x11_saved_display = xstrdup(disp); | |
3140 | else if (strcmp(disp, x11_saved_display) != 0) { | |
3141 | error("x11_request_forwarding_with_spoofing: different " | |
3142 | "$DISPLAY already forwarded"); | |
3143 | return; | |
3144 | } | |
3145 | ||
3146 | cp = disp; | |
3147 | if (disp) | |
3148 | cp = strchr(disp, ':'); | |
3149 | if (cp) | |
3150 | cp = strchr(cp, '.'); | |
3151 | if (cp) | |
3152 | screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL); | |
3153 | else | |
3154 | screen_number = 0; | |
3155 | ||
3156 | if (x11_saved_proto == NULL) { | |
3157 | /* Save protocol name. */ | |
3158 | x11_saved_proto = xstrdup(proto); | |
3159 | /* | |
3160 | * Extract real authentication data and generate fake data | |
3161 | * of the same length. | |
3162 | */ | |
3163 | x11_saved_data = xmalloc(data_len); | |
3164 | x11_fake_data = xmalloc(data_len); | |
3165 | for (i = 0; i < data_len; i++) { | |
3166 | if (sscanf(data + 2 * i, "%2x", &value) != 1) | |
3167 | fatal("x11_request_forwarding: bad " | |
3168 | "authentication data: %.100s", data); | |
3169 | if (i % 4 == 0) | |
3170 | rnd = arc4random(); | |
3171 | x11_saved_data[i] = value; | |
3172 | x11_fake_data[i] = rnd & 0xff; | |
3173 | rnd >>= 8; | |
3174 | } | |
3175 | x11_saved_data_len = data_len; | |
3176 | x11_fake_data_len = data_len; | |
3177 | } | |
3178 | ||
3179 | /* Convert the fake data into hex. */ | |
3180 | new_data = tohex(x11_fake_data, data_len); | |
3181 | ||
3182 | /* Send the request packet. */ | |
3183 | if (compat20) { | |
3184 | channel_request_start(client_session_id, "x11-req", 0); | |
3185 | packet_put_char(0); /* XXX bool single connection */ | |
3186 | } else { | |
3187 | packet_start(SSH_CMSG_X11_REQUEST_FORWARDING); | |
3188 | } | |
3189 | packet_put_cstring(proto); | |
3190 | packet_put_cstring(new_data); | |
3191 | packet_put_int(screen_number); | |
3192 | packet_send(); | |
3193 | packet_write_wait(); | |
3194 | xfree(new_data); | |
3195 | } | |
3196 | ||
3197 | ||
3198 | /* -- agent forwarding */ | |
3199 | ||
3200 | /* Sends a message to the server to request authentication fd forwarding. */ | |
3201 | ||
3202 | void | |
3203 | auth_request_forwarding(void) | |
3204 | { | |
3205 | packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING); | |
3206 | packet_send(); | |
3207 | packet_write_wait(); | |
3208 | } |