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1 | /* | |
2 | * Author: Tatu Ylonen <ylo@cs.hut.fi> | |
3 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland | |
4 | * All rights reserved | |
5 | * This file contains functions for generic socket connection forwarding. | |
6 | * There is also code for initiating connection forwarding for X11 connections, | |
7 | * arbitrary tcp/ip connections, and the authentication agent connection. | |
8 | * | |
9 | * As far as I am concerned, the code I have written for this software | |
10 | * can be used freely for any purpose. Any derived versions of this | |
11 | * software must be clearly marked as such, and if the derived work is | |
12 | * incompatible with the protocol description in the RFC file, it must be | |
13 | * called by a name other than "ssh" or "Secure Shell". | |
14 | * | |
15 | * SSH2 support added by Markus Friedl. | |
16 | * Copyright (c) 1999, 2000, 2001 Markus Friedl. All rights reserved. | |
17 | * Copyright (c) 1999 Dug Song. All rights reserved. | |
18 | * Copyright (c) 1999 Theo de Raadt. All rights reserved. | |
19 | * | |
20 | * Redistribution and use in source and binary forms, with or without | |
21 | * modification, are permitted provided that the following conditions | |
22 | * are met: | |
23 | * 1. Redistributions of source code must retain the above copyright | |
24 | * notice, this list of conditions and the following disclaimer. | |
25 | * 2. Redistributions in binary form must reproduce the above copyright | |
26 | * notice, this list of conditions and the following disclaimer in the | |
27 | * documentation and/or other materials provided with the distribution. | |
28 | * | |
29 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR | |
30 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES | |
31 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. | |
32 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, | |
33 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | |
34 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
35 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
36 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
37 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF | |
38 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
39 | */ | |
40 | ||
41 | #include "includes.h" | |
42 | RCSID("$OpenBSD: channels.c,v 1.150 2001/12/20 22:50:24 djm Exp $"); | |
43 | ||
44 | #include "ssh.h" | |
45 | #include "ssh1.h" | |
46 | #include "ssh2.h" | |
47 | #include "packet.h" | |
48 | #include "xmalloc.h" | |
49 | #include "uidswap.h" | |
50 | #include "log.h" | |
51 | #include "misc.h" | |
52 | #include "channels.h" | |
53 | #include "compat.h" | |
54 | #include "canohost.h" | |
55 | #include "key.h" | |
56 | #include "authfd.h" | |
57 | #include "pathnames.h" | |
58 | ||
59 | ||
60 | /* -- channel core */ | |
61 | ||
62 | /* | |
63 | * Pointer to an array containing all allocated channels. The array is | |
64 | * dynamically extended as needed. | |
65 | */ | |
66 | static Channel **channels = NULL; | |
67 | ||
68 | /* | |
69 | * Size of the channel array. All slots of the array must always be | |
70 | * initialized (at least the type field); unused slots set to NULL | |
71 | */ | |
72 | static int channels_alloc = 0; | |
73 | ||
74 | /* | |
75 | * Maximum file descriptor value used in any of the channels. This is | |
76 | * updated in channel_new. | |
77 | */ | |
78 | static int channel_max_fd = 0; | |
79 | ||
80 | ||
81 | /* -- tcp forwarding */ | |
82 | ||
83 | /* | |
84 | * Data structure for storing which hosts are permitted for forward requests. | |
85 | * The local sides of any remote forwards are stored in this array to prevent | |
86 | * a corrupt remote server from accessing arbitrary TCP/IP ports on our local | |
87 | * network (which might be behind a firewall). | |
88 | */ | |
89 | typedef struct { | |
90 | char *host_to_connect; /* Connect to 'host'. */ | |
91 | u_short port_to_connect; /* Connect to 'port'. */ | |
92 | u_short listen_port; /* Remote side should listen port number. */ | |
93 | } ForwardPermission; | |
94 | ||
95 | /* List of all permitted host/port pairs to connect. */ | |
96 | static ForwardPermission permitted_opens[SSH_MAX_FORWARDS_PER_DIRECTION]; | |
97 | ||
98 | /* Number of permitted host/port pairs in the array. */ | |
99 | static int num_permitted_opens = 0; | |
100 | /* | |
101 | * If this is true, all opens are permitted. This is the case on the server | |
102 | * on which we have to trust the client anyway, and the user could do | |
103 | * anything after logging in anyway. | |
104 | */ | |
105 | static int all_opens_permitted = 0; | |
106 | ||
107 | ||
108 | /* -- X11 forwarding */ | |
109 | ||
110 | /* Maximum number of fake X11 displays to try. */ | |
111 | #define MAX_DISPLAYS 1000 | |
112 | ||
113 | /* Saved X11 authentication protocol name. */ | |
114 | static char *x11_saved_proto = NULL; | |
115 | ||
116 | /* Saved X11 authentication data. This is the real data. */ | |
117 | static char *x11_saved_data = NULL; | |
118 | static u_int x11_saved_data_len = 0; | |
119 | ||
120 | /* | |
121 | * Fake X11 authentication data. This is what the server will be sending us; | |
122 | * we should replace any occurrences of this by the real data. | |
123 | */ | |
124 | static char *x11_fake_data = NULL; | |
125 | static u_int x11_fake_data_len; | |
126 | ||
127 | ||
128 | /* -- agent forwarding */ | |
129 | ||
130 | #define NUM_SOCKS 10 | |
131 | ||
132 | /* Name and directory of socket for authentication agent forwarding. */ | |
133 | static char *auth_sock_name = NULL; | |
134 | static char *auth_sock_dir = NULL; | |
135 | ||
136 | /* AF_UNSPEC or AF_INET or AF_INET6 */ | |
137 | static int IPv4or6 = AF_UNSPEC; | |
138 | ||
139 | /* helper */ | |
140 | static void port_open_helper(Channel *c, char *rtype); | |
141 | ||
142 | /* -- channel core */ | |
143 | ||
144 | Channel * | |
145 | channel_lookup(int id) | |
146 | { | |
147 | Channel *c; | |
148 | ||
149 | if (id < 0 || id > channels_alloc) { | |
150 | log("channel_lookup: %d: bad id", id); | |
151 | return NULL; | |
152 | } | |
153 | c = channels[id]; | |
154 | if (c == NULL) { | |
155 | log("channel_lookup: %d: bad id: channel free", id); | |
156 | return NULL; | |
157 | } | |
158 | return c; | |
159 | } | |
160 | ||
161 | /* | |
162 | * Register filedescriptors for a channel, used when allocating a channel or | |
163 | * when the channel consumer/producer is ready, e.g. shell exec'd | |
164 | */ | |
165 | ||
166 | static void | |
167 | channel_register_fds(Channel *c, int rfd, int wfd, int efd, | |
168 | int extusage, int nonblock) | |
169 | { | |
170 | /* Update the maximum file descriptor value. */ | |
171 | channel_max_fd = MAX(channel_max_fd, rfd); | |
172 | channel_max_fd = MAX(channel_max_fd, wfd); | |
173 | channel_max_fd = MAX(channel_max_fd, efd); | |
174 | ||
175 | /* XXX set close-on-exec -markus */ | |
176 | ||
177 | c->rfd = rfd; | |
178 | c->wfd = wfd; | |
179 | c->sock = (rfd == wfd) ? rfd : -1; | |
180 | c->efd = efd; | |
181 | c->extended_usage = extusage; | |
182 | ||
183 | /* XXX ugly hack: nonblock is only set by the server */ | |
184 | if (nonblock && isatty(c->rfd)) { | |
185 | debug("channel %d: rfd %d isatty", c->self, c->rfd); | |
186 | c->isatty = 1; | |
187 | if (!isatty(c->wfd)) { | |
188 | error("channel %d: wfd %d is not a tty?", | |
189 | c->self, c->wfd); | |
190 | } | |
191 | } else { | |
192 | c->isatty = 0; | |
193 | } | |
194 | ||
195 | /* enable nonblocking mode */ | |
196 | if (nonblock) { | |
197 | if (rfd != -1) | |
198 | set_nonblock(rfd); | |
199 | if (wfd != -1) | |
200 | set_nonblock(wfd); | |
201 | if (efd != -1) | |
202 | set_nonblock(efd); | |
203 | } | |
204 | } | |
205 | ||
206 | /* | |
207 | * Allocate a new channel object and set its type and socket. This will cause | |
208 | * remote_name to be freed. | |
209 | */ | |
210 | ||
211 | Channel * | |
212 | channel_new(char *ctype, int type, int rfd, int wfd, int efd, | |
213 | int window, int maxpack, int extusage, char *remote_name, int nonblock) | |
214 | { | |
215 | int i, found; | |
216 | Channel *c; | |
217 | ||
218 | /* Do initial allocation if this is the first call. */ | |
219 | if (channels_alloc == 0) { | |
220 | chan_init(); | |
221 | channels_alloc = 10; | |
222 | channels = xmalloc(channels_alloc * sizeof(Channel *)); | |
223 | for (i = 0; i < channels_alloc; i++) | |
224 | channels[i] = NULL; | |
225 | fatal_add_cleanup((void (*) (void *)) channel_free_all, NULL); | |
226 | } | |
227 | /* Try to find a free slot where to put the new channel. */ | |
228 | for (found = -1, i = 0; i < channels_alloc; i++) | |
229 | if (channels[i] == NULL) { | |
230 | /* Found a free slot. */ | |
231 | found = i; | |
232 | break; | |
233 | } | |
234 | if (found == -1) { | |
235 | /* There are no free slots. Take last+1 slot and expand the array. */ | |
236 | found = channels_alloc; | |
237 | channels_alloc += 10; | |
238 | debug2("channel: expanding %d", channels_alloc); | |
239 | channels = xrealloc(channels, channels_alloc * sizeof(Channel *)); | |
240 | for (i = found; i < channels_alloc; i++) | |
241 | channels[i] = NULL; | |
242 | } | |
243 | /* Initialize and return new channel. */ | |
244 | c = channels[found] = xmalloc(sizeof(Channel)); | |
245 | memset(c, 0, sizeof(Channel)); | |
246 | buffer_init(&c->input); | |
247 | buffer_init(&c->output); | |
248 | buffer_init(&c->extended); | |
249 | chan_init_iostates(c); | |
250 | channel_register_fds(c, rfd, wfd, efd, extusage, nonblock); | |
251 | c->self = found; | |
252 | c->type = type; | |
253 | c->ctype = ctype; | |
254 | c->local_window = window; | |
255 | c->local_window_max = window; | |
256 | c->local_consumed = 0; | |
257 | c->local_maxpacket = maxpack; | |
258 | c->remote_id = -1; | |
259 | c->remote_name = remote_name; | |
260 | c->remote_window = 0; | |
261 | c->remote_maxpacket = 0; | |
262 | c->cb_fn = NULL; | |
263 | c->cb_arg = NULL; | |
264 | c->cb_event = 0; | |
265 | c->force_drain = 0; | |
266 | c->single_connection = 0; | |
267 | c->detach_user = NULL; | |
268 | c->input_filter = NULL; | |
269 | debug("channel %d: new [%s]", found, remote_name); | |
270 | return c; | |
271 | } | |
272 | ||
273 | static int | |
274 | channel_find_maxfd(void) | |
275 | { | |
276 | int i, max = 0; | |
277 | Channel *c; | |
278 | ||
279 | for (i = 0; i < channels_alloc; i++) { | |
280 | c = channels[i]; | |
281 | if (c != NULL) { | |
282 | max = MAX(max, c->rfd); | |
283 | max = MAX(max, c->wfd); | |
284 | max = MAX(max, c->efd); | |
285 | } | |
286 | } | |
287 | return max; | |
288 | } | |
289 | ||
290 | int | |
291 | channel_close_fd(int *fdp) | |
292 | { | |
293 | int ret = 0, fd = *fdp; | |
294 | ||
295 | if (fd != -1) { | |
296 | ret = close(fd); | |
297 | *fdp = -1; | |
298 | if (fd == channel_max_fd) | |
299 | channel_max_fd = channel_find_maxfd(); | |
300 | } | |
301 | return ret; | |
302 | } | |
303 | ||
304 | /* Close all channel fd/socket. */ | |
305 | ||
306 | static void | |
307 | channel_close_fds(Channel *c) | |
308 | { | |
309 | debug3("channel_close_fds: channel %d: r %d w %d e %d", | |
310 | c->self, c->rfd, c->wfd, c->efd); | |
311 | ||
312 | channel_close_fd(&c->sock); | |
313 | channel_close_fd(&c->rfd); | |
314 | channel_close_fd(&c->wfd); | |
315 | channel_close_fd(&c->efd); | |
316 | } | |
317 | ||
318 | /* Free the channel and close its fd/socket. */ | |
319 | ||
320 | void | |
321 | channel_free(Channel *c) | |
322 | { | |
323 | char *s; | |
324 | int i, n; | |
325 | ||
326 | for (n = 0, i = 0; i < channels_alloc; i++) | |
327 | if (channels[i]) | |
328 | n++; | |
329 | debug("channel_free: channel %d: %s, nchannels %d", c->self, | |
330 | c->remote_name ? c->remote_name : "???", n); | |
331 | ||
332 | s = channel_open_message(); | |
333 | debug3("channel_free: status: %s", s); | |
334 | xfree(s); | |
335 | ||
336 | if (c->sock != -1) | |
337 | shutdown(c->sock, SHUT_RDWR); | |
338 | channel_close_fds(c); | |
339 | buffer_free(&c->input); | |
340 | buffer_free(&c->output); | |
341 | buffer_free(&c->extended); | |
342 | if (c->remote_name) { | |
343 | xfree(c->remote_name); | |
344 | c->remote_name = NULL; | |
345 | } | |
346 | channels[c->self] = NULL; | |
347 | xfree(c); | |
348 | } | |
349 | ||
350 | void | |
351 | channel_free_all(void) | |
352 | { | |
353 | int i; | |
354 | ||
355 | for (i = 0; i < channels_alloc; i++) | |
356 | if (channels[i] != NULL) | |
357 | channel_free(channels[i]); | |
358 | } | |
359 | ||
360 | /* | |
361 | * Closes the sockets/fds of all channels. This is used to close extra file | |
362 | * descriptors after a fork. | |
363 | */ | |
364 | ||
365 | void | |
366 | channel_close_all(void) | |
367 | { | |
368 | int i; | |
369 | ||
370 | for (i = 0; i < channels_alloc; i++) | |
371 | if (channels[i] != NULL) | |
372 | channel_close_fds(channels[i]); | |
373 | } | |
374 | ||
375 | /* | |
376 | * Stop listening to channels. | |
377 | */ | |
378 | ||
379 | void | |
380 | channel_stop_listening(void) | |
381 | { | |
382 | int i; | |
383 | Channel *c; | |
384 | ||
385 | for (i = 0; i < channels_alloc; i++) { | |
386 | c = channels[i]; | |
387 | if (c != NULL) { | |
388 | switch (c->type) { | |
389 | case SSH_CHANNEL_AUTH_SOCKET: | |
390 | case SSH_CHANNEL_PORT_LISTENER: | |
391 | case SSH_CHANNEL_RPORT_LISTENER: | |
392 | case SSH_CHANNEL_X11_LISTENER: | |
393 | channel_close_fd(&c->sock); | |
394 | channel_free(c); | |
395 | break; | |
396 | } | |
397 | } | |
398 | } | |
399 | } | |
400 | ||
401 | /* | |
402 | * Returns true if no channel has too much buffered data, and false if one or | |
403 | * more channel is overfull. | |
404 | */ | |
405 | ||
406 | int | |
407 | channel_not_very_much_buffered_data(void) | |
408 | { | |
409 | u_int i; | |
410 | Channel *c; | |
411 | ||
412 | for (i = 0; i < channels_alloc; i++) { | |
413 | c = channels[i]; | |
414 | if (c != NULL && c->type == SSH_CHANNEL_OPEN) { | |
415 | #if 0 | |
416 | if (!compat20 && | |
417 | buffer_len(&c->input) > packet_get_maxsize()) { | |
418 | debug("channel %d: big input buffer %d", | |
419 | c->self, buffer_len(&c->input)); | |
420 | return 0; | |
421 | } | |
422 | #endif | |
423 | if (buffer_len(&c->output) > packet_get_maxsize()) { | |
424 | debug("channel %d: big output buffer %d > %d", | |
425 | c->self, buffer_len(&c->output), | |
426 | packet_get_maxsize()); | |
427 | return 0; | |
428 | } | |
429 | } | |
430 | } | |
431 | return 1; | |
432 | } | |
433 | ||
434 | /* Returns true if any channel is still open. */ | |
435 | ||
436 | int | |
437 | channel_still_open(void) | |
438 | { | |
439 | int i; | |
440 | Channel *c; | |
441 | ||
442 | for (i = 0; i < channels_alloc; i++) { | |
443 | c = channels[i]; | |
444 | if (c == NULL) | |
445 | continue; | |
446 | switch (c->type) { | |
447 | case SSH_CHANNEL_X11_LISTENER: | |
448 | case SSH_CHANNEL_PORT_LISTENER: | |
449 | case SSH_CHANNEL_RPORT_LISTENER: | |
450 | case SSH_CHANNEL_CLOSED: | |
451 | case SSH_CHANNEL_AUTH_SOCKET: | |
452 | case SSH_CHANNEL_DYNAMIC: | |
453 | case SSH_CHANNEL_CONNECTING: | |
454 | case SSH_CHANNEL_ZOMBIE: | |
455 | continue; | |
456 | case SSH_CHANNEL_LARVAL: | |
457 | if (!compat20) | |
458 | fatal("cannot happen: SSH_CHANNEL_LARVAL"); | |
459 | continue; | |
460 | case SSH_CHANNEL_OPENING: | |
461 | case SSH_CHANNEL_OPEN: | |
462 | case SSH_CHANNEL_X11_OPEN: | |
463 | return 1; | |
464 | case SSH_CHANNEL_INPUT_DRAINING: | |
465 | case SSH_CHANNEL_OUTPUT_DRAINING: | |
466 | if (!compat13) | |
467 | fatal("cannot happen: OUT_DRAIN"); | |
468 | return 1; | |
469 | default: | |
470 | fatal("channel_still_open: bad channel type %d", c->type); | |
471 | /* NOTREACHED */ | |
472 | } | |
473 | } | |
474 | return 0; | |
475 | } | |
476 | ||
477 | /* Returns the id of an open channel suitable for keepaliving */ | |
478 | ||
479 | int | |
480 | channel_find_open(void) | |
481 | { | |
482 | int i; | |
483 | Channel *c; | |
484 | ||
485 | for (i = 0; i < channels_alloc; i++) { | |
486 | c = channels[i]; | |
487 | if (c == NULL) | |
488 | continue; | |
489 | switch (c->type) { | |
490 | case SSH_CHANNEL_CLOSED: | |
491 | case SSH_CHANNEL_DYNAMIC: | |
492 | case SSH_CHANNEL_X11_LISTENER: | |
493 | case SSH_CHANNEL_PORT_LISTENER: | |
494 | case SSH_CHANNEL_RPORT_LISTENER: | |
495 | case SSH_CHANNEL_OPENING: | |
496 | case SSH_CHANNEL_CONNECTING: | |
497 | case SSH_CHANNEL_ZOMBIE: | |
498 | continue; | |
499 | case SSH_CHANNEL_LARVAL: | |
500 | case SSH_CHANNEL_AUTH_SOCKET: | |
501 | case SSH_CHANNEL_OPEN: | |
502 | case SSH_CHANNEL_X11_OPEN: | |
503 | return i; | |
504 | case SSH_CHANNEL_INPUT_DRAINING: | |
505 | case SSH_CHANNEL_OUTPUT_DRAINING: | |
506 | if (!compat13) | |
507 | fatal("cannot happen: OUT_DRAIN"); | |
508 | return i; | |
509 | default: | |
510 | fatal("channel_find_open: bad channel type %d", c->type); | |
511 | /* NOTREACHED */ | |
512 | } | |
513 | } | |
514 | return -1; | |
515 | } | |
516 | ||
517 | ||
518 | /* | |
519 | * Returns a message describing the currently open forwarded connections, | |
520 | * suitable for sending to the client. The message contains crlf pairs for | |
521 | * newlines. | |
522 | */ | |
523 | ||
524 | char * | |
525 | channel_open_message(void) | |
526 | { | |
527 | Buffer buffer; | |
528 | Channel *c; | |
529 | char buf[1024], *cp; | |
530 | int i; | |
531 | ||
532 | buffer_init(&buffer); | |
533 | snprintf(buf, sizeof buf, "The following connections are open:\r\n"); | |
534 | buffer_append(&buffer, buf, strlen(buf)); | |
535 | for (i = 0; i < channels_alloc; i++) { | |
536 | c = channels[i]; | |
537 | if (c == NULL) | |
538 | continue; | |
539 | switch (c->type) { | |
540 | case SSH_CHANNEL_X11_LISTENER: | |
541 | case SSH_CHANNEL_PORT_LISTENER: | |
542 | case SSH_CHANNEL_RPORT_LISTENER: | |
543 | case SSH_CHANNEL_CLOSED: | |
544 | case SSH_CHANNEL_AUTH_SOCKET: | |
545 | case SSH_CHANNEL_ZOMBIE: | |
546 | continue; | |
547 | case SSH_CHANNEL_LARVAL: | |
548 | case SSH_CHANNEL_OPENING: | |
549 | case SSH_CHANNEL_CONNECTING: | |
550 | case SSH_CHANNEL_DYNAMIC: | |
551 | case SSH_CHANNEL_OPEN: | |
552 | case SSH_CHANNEL_X11_OPEN: | |
553 | case SSH_CHANNEL_INPUT_DRAINING: | |
554 | case SSH_CHANNEL_OUTPUT_DRAINING: | |
555 | snprintf(buf, sizeof buf, " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d)\r\n", | |
556 | c->self, c->remote_name, | |
557 | c->type, c->remote_id, | |
558 | c->istate, buffer_len(&c->input), | |
559 | c->ostate, buffer_len(&c->output), | |
560 | c->rfd, c->wfd); | |
561 | buffer_append(&buffer, buf, strlen(buf)); | |
562 | continue; | |
563 | default: | |
564 | fatal("channel_open_message: bad channel type %d", c->type); | |
565 | /* NOTREACHED */ | |
566 | } | |
567 | } | |
568 | buffer_append(&buffer, "\0", 1); | |
569 | cp = xstrdup(buffer_ptr(&buffer)); | |
570 | buffer_free(&buffer); | |
571 | return cp; | |
572 | } | |
573 | ||
574 | void | |
575 | channel_send_open(int id) | |
576 | { | |
577 | Channel *c = channel_lookup(id); | |
578 | if (c == NULL) { | |
579 | log("channel_send_open: %d: bad id", id); | |
580 | return; | |
581 | } | |
582 | debug("send channel open %d", id); | |
583 | packet_start(SSH2_MSG_CHANNEL_OPEN); | |
584 | packet_put_cstring(c->ctype); | |
585 | packet_put_int(c->self); | |
586 | packet_put_int(c->local_window); | |
587 | packet_put_int(c->local_maxpacket); | |
588 | packet_send(); | |
589 | } | |
590 | ||
591 | void | |
592 | channel_request(int id, char *service, int wantconfirm) | |
593 | { | |
594 | channel_request_start(id, service, wantconfirm); | |
595 | packet_send(); | |
596 | debug("channel request %d: %s", id, service) ; | |
597 | } | |
598 | void | |
599 | channel_request_start(int id, char *service, int wantconfirm) | |
600 | { | |
601 | Channel *c = channel_lookup(id); | |
602 | if (c == NULL) { | |
603 | log("channel_request: %d: bad id", id); | |
604 | return; | |
605 | } | |
606 | packet_start(SSH2_MSG_CHANNEL_REQUEST); | |
607 | packet_put_int(c->remote_id); | |
608 | packet_put_cstring(service); | |
609 | packet_put_char(wantconfirm); | |
610 | } | |
611 | void | |
612 | channel_register_callback(int id, int mtype, channel_callback_fn *fn, void *arg) | |
613 | { | |
614 | Channel *c = channel_lookup(id); | |
615 | if (c == NULL) { | |
616 | log("channel_register_callback: %d: bad id", id); | |
617 | return; | |
618 | } | |
619 | c->cb_event = mtype; | |
620 | c->cb_fn = fn; | |
621 | c->cb_arg = arg; | |
622 | } | |
623 | void | |
624 | channel_register_cleanup(int id, channel_callback_fn *fn) | |
625 | { | |
626 | Channel *c = channel_lookup(id); | |
627 | if (c == NULL) { | |
628 | log("channel_register_cleanup: %d: bad id", id); | |
629 | return; | |
630 | } | |
631 | c->detach_user = fn; | |
632 | } | |
633 | void | |
634 | channel_cancel_cleanup(int id) | |
635 | { | |
636 | Channel *c = channel_lookup(id); | |
637 | if (c == NULL) { | |
638 | log("channel_cancel_cleanup: %d: bad id", id); | |
639 | return; | |
640 | } | |
641 | c->detach_user = NULL; | |
642 | } | |
643 | void | |
644 | channel_register_filter(int id, channel_filter_fn *fn) | |
645 | { | |
646 | Channel *c = channel_lookup(id); | |
647 | if (c == NULL) { | |
648 | log("channel_register_filter: %d: bad id", id); | |
649 | return; | |
650 | } | |
651 | c->input_filter = fn; | |
652 | } | |
653 | ||
654 | void | |
655 | channel_set_fds(int id, int rfd, int wfd, int efd, | |
656 | int extusage, int nonblock) | |
657 | { | |
658 | Channel *c = channel_lookup(id); | |
659 | if (c == NULL || c->type != SSH_CHANNEL_LARVAL) | |
660 | fatal("channel_activate for non-larval channel %d.", id); | |
661 | channel_register_fds(c, rfd, wfd, efd, extusage, nonblock); | |
662 | c->type = SSH_CHANNEL_OPEN; | |
663 | /* XXX window size? */ | |
664 | c->local_window = c->local_window_max = c->local_maxpacket * 2; | |
665 | packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST); | |
666 | packet_put_int(c->remote_id); | |
667 | packet_put_int(c->local_window); | |
668 | packet_send(); | |
669 | } | |
670 | ||
671 | /* | |
672 | * 'channel_pre*' are called just before select() to add any bits relevant to | |
673 | * channels in the select bitmasks. | |
674 | */ | |
675 | /* | |
676 | * 'channel_post*': perform any appropriate operations for channels which | |
677 | * have events pending. | |
678 | */ | |
679 | typedef void chan_fn(Channel *c, fd_set * readset, fd_set * writeset); | |
680 | chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE]; | |
681 | chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE]; | |
682 | ||
683 | static void | |
684 | channel_pre_listener(Channel *c, fd_set * readset, fd_set * writeset) | |
685 | { | |
686 | FD_SET(c->sock, readset); | |
687 | } | |
688 | ||
689 | static void | |
690 | channel_pre_connecting(Channel *c, fd_set * readset, fd_set * writeset) | |
691 | { | |
692 | debug3("channel %d: waiting for connection", c->self); | |
693 | FD_SET(c->sock, writeset); | |
694 | } | |
695 | ||
696 | static void | |
697 | channel_pre_open_13(Channel *c, fd_set * readset, fd_set * writeset) | |
698 | { | |
699 | if (buffer_len(&c->input) < packet_get_maxsize()) | |
700 | FD_SET(c->sock, readset); | |
701 | if (buffer_len(&c->output) > 0) | |
702 | FD_SET(c->sock, writeset); | |
703 | } | |
704 | ||
705 | static void | |
706 | channel_pre_open_15(Channel *c, fd_set * readset, fd_set * writeset) | |
707 | { | |
708 | /* test whether sockets are 'alive' for read/write */ | |
709 | if (c->istate == CHAN_INPUT_OPEN) | |
710 | if (buffer_len(&c->input) < packet_get_maxsize()) | |
711 | FD_SET(c->sock, readset); | |
712 | if (c->ostate == CHAN_OUTPUT_OPEN || | |
713 | c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { | |
714 | if (buffer_len(&c->output) > 0) { | |
715 | FD_SET(c->sock, writeset); | |
716 | } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { | |
717 | chan_obuf_empty(c); | |
718 | } | |
719 | } | |
720 | } | |
721 | ||
722 | static void | |
723 | channel_pre_open_20(Channel *c, fd_set * readset, fd_set * writeset) | |
724 | { | |
725 | if (c->istate == CHAN_INPUT_OPEN && | |
726 | c->remote_window > 0 && | |
727 | buffer_len(&c->input) < c->remote_window) | |
728 | FD_SET(c->rfd, readset); | |
729 | if (c->ostate == CHAN_OUTPUT_OPEN || | |
730 | c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { | |
731 | if (buffer_len(&c->output) > 0) { | |
732 | FD_SET(c->wfd, writeset); | |
733 | } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { | |
734 | chan_obuf_empty(c); | |
735 | } | |
736 | } | |
737 | /** XXX check close conditions, too */ | |
738 | if (c->efd != -1) { | |
739 | if (c->extended_usage == CHAN_EXTENDED_WRITE && | |
740 | buffer_len(&c->extended) > 0) | |
741 | FD_SET(c->efd, writeset); | |
742 | else if (c->extended_usage == CHAN_EXTENDED_READ && | |
743 | buffer_len(&c->extended) < c->remote_window) | |
744 | FD_SET(c->efd, readset); | |
745 | } | |
746 | } | |
747 | ||
748 | static void | |
749 | channel_pre_input_draining(Channel *c, fd_set * readset, fd_set * writeset) | |
750 | { | |
751 | if (buffer_len(&c->input) == 0) { | |
752 | packet_start(SSH_MSG_CHANNEL_CLOSE); | |
753 | packet_put_int(c->remote_id); | |
754 | packet_send(); | |
755 | c->type = SSH_CHANNEL_CLOSED; | |
756 | debug("channel %d: closing after input drain.", c->self); | |
757 | } | |
758 | } | |
759 | ||
760 | static void | |
761 | channel_pre_output_draining(Channel *c, fd_set * readset, fd_set * writeset) | |
762 | { | |
763 | if (buffer_len(&c->output) == 0) | |
764 | chan_mark_dead(c); | |
765 | else | |
766 | FD_SET(c->sock, writeset); | |
767 | } | |
768 | ||
769 | /* | |
770 | * This is a special state for X11 authentication spoofing. An opened X11 | |
771 | * connection (when authentication spoofing is being done) remains in this | |
772 | * state until the first packet has been completely read. The authentication | |
773 | * data in that packet is then substituted by the real data if it matches the | |
774 | * fake data, and the channel is put into normal mode. | |
775 | * XXX All this happens at the client side. | |
776 | * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok | |
777 | */ | |
778 | static int | |
779 | x11_open_helper(Buffer *b) | |
780 | { | |
781 | u_char *ucp; | |
782 | u_int proto_len, data_len; | |
783 | ||
784 | /* Check if the fixed size part of the packet is in buffer. */ | |
785 | if (buffer_len(b) < 12) | |
786 | return 0; | |
787 | ||
788 | /* Parse the lengths of variable-length fields. */ | |
789 | ucp = (u_char *) buffer_ptr(b); | |
790 | if (ucp[0] == 0x42) { /* Byte order MSB first. */ | |
791 | proto_len = 256 * ucp[6] + ucp[7]; | |
792 | data_len = 256 * ucp[8] + ucp[9]; | |
793 | } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */ | |
794 | proto_len = ucp[6] + 256 * ucp[7]; | |
795 | data_len = ucp[8] + 256 * ucp[9]; | |
796 | } else { | |
797 | debug("Initial X11 packet contains bad byte order byte: 0x%x", | |
798 | ucp[0]); | |
799 | return -1; | |
800 | } | |
801 | ||
802 | /* Check if the whole packet is in buffer. */ | |
803 | if (buffer_len(b) < | |
804 | 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3)) | |
805 | return 0; | |
806 | ||
807 | /* Check if authentication protocol matches. */ | |
808 | if (proto_len != strlen(x11_saved_proto) || | |
809 | memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) { | |
810 | debug("X11 connection uses different authentication protocol."); | |
811 | return -1; | |
812 | } | |
813 | /* Check if authentication data matches our fake data. */ | |
814 | if (data_len != x11_fake_data_len || | |
815 | memcmp(ucp + 12 + ((proto_len + 3) & ~3), | |
816 | x11_fake_data, x11_fake_data_len) != 0) { | |
817 | debug("X11 auth data does not match fake data."); | |
818 | return -1; | |
819 | } | |
820 | /* Check fake data length */ | |
821 | if (x11_fake_data_len != x11_saved_data_len) { | |
822 | error("X11 fake_data_len %d != saved_data_len %d", | |
823 | x11_fake_data_len, x11_saved_data_len); | |
824 | return -1; | |
825 | } | |
826 | /* | |
827 | * Received authentication protocol and data match | |
828 | * our fake data. Substitute the fake data with real | |
829 | * data. | |
830 | */ | |
831 | memcpy(ucp + 12 + ((proto_len + 3) & ~3), | |
832 | x11_saved_data, x11_saved_data_len); | |
833 | return 1; | |
834 | } | |
835 | ||
836 | static void | |
837 | channel_pre_x11_open_13(Channel *c, fd_set * readset, fd_set * writeset) | |
838 | { | |
839 | int ret = x11_open_helper(&c->output); | |
840 | if (ret == 1) { | |
841 | /* Start normal processing for the channel. */ | |
842 | c->type = SSH_CHANNEL_OPEN; | |
843 | channel_pre_open_13(c, readset, writeset); | |
844 | } else if (ret == -1) { | |
845 | /* | |
846 | * We have received an X11 connection that has bad | |
847 | * authentication information. | |
848 | */ | |
849 | log("X11 connection rejected because of wrong authentication."); | |
850 | buffer_clear(&c->input); | |
851 | buffer_clear(&c->output); | |
852 | channel_close_fd(&c->sock); | |
853 | c->sock = -1; | |
854 | c->type = SSH_CHANNEL_CLOSED; | |
855 | packet_start(SSH_MSG_CHANNEL_CLOSE); | |
856 | packet_put_int(c->remote_id); | |
857 | packet_send(); | |
858 | } | |
859 | } | |
860 | ||
861 | static void | |
862 | channel_pre_x11_open(Channel *c, fd_set * readset, fd_set * writeset) | |
863 | { | |
864 | int ret = x11_open_helper(&c->output); | |
865 | ||
866 | /* c->force_drain = 1; */ | |
867 | ||
868 | if (ret == 1) { | |
869 | c->type = SSH_CHANNEL_OPEN; | |
870 | if (compat20) | |
871 | channel_pre_open_20(c, readset, writeset); | |
872 | else | |
873 | channel_pre_open_15(c, readset, writeset); | |
874 | } else if (ret == -1) { | |
875 | debug("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate); | |
876 | chan_read_failed(c); /** force close? */ | |
877 | chan_write_failed(c); | |
878 | debug("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate); | |
879 | } | |
880 | } | |
881 | ||
882 | /* try to decode a socks4 header */ | |
883 | static int | |
884 | channel_decode_socks4(Channel *c, fd_set * readset, fd_set * writeset) | |
885 | { | |
886 | u_char *p, *host; | |
887 | int len, have, i, found; | |
888 | char username[256]; | |
889 | struct { | |
890 | u_int8_t version; | |
891 | u_int8_t command; | |
892 | u_int16_t dest_port; | |
893 | struct in_addr dest_addr; | |
894 | } s4_req, s4_rsp; | |
895 | ||
896 | debug2("channel %d: decode socks4", c->self); | |
897 | ||
898 | have = buffer_len(&c->input); | |
899 | len = sizeof(s4_req); | |
900 | if (have < len) | |
901 | return 0; | |
902 | p = buffer_ptr(&c->input); | |
903 | for (found = 0, i = len; i < have; i++) { | |
904 | if (p[i] == '\0') { | |
905 | found = 1; | |
906 | break; | |
907 | } | |
908 | if (i > 1024) { | |
909 | /* the peer is probably sending garbage */ | |
910 | debug("channel %d: decode socks4: too long", | |
911 | c->self); | |
912 | return -1; | |
913 | } | |
914 | } | |
915 | if (!found) | |
916 | return 0; | |
917 | buffer_get(&c->input, (char *)&s4_req.version, 1); | |
918 | buffer_get(&c->input, (char *)&s4_req.command, 1); | |
919 | buffer_get(&c->input, (char *)&s4_req.dest_port, 2); | |
920 | buffer_get(&c->input, (char *)&s4_req.dest_addr, 4); | |
921 | have = buffer_len(&c->input); | |
922 | p = buffer_ptr(&c->input); | |
923 | len = strlen(p); | |
924 | debug2("channel %d: decode socks4: user %s/%d", c->self, p, len); | |
925 | if (len > have) | |
926 | fatal("channel %d: decode socks4: len %d > have %d", | |
927 | c->self, len, have); | |
928 | strlcpy(username, p, sizeof(username)); | |
929 | buffer_consume(&c->input, len); | |
930 | buffer_consume(&c->input, 1); /* trailing '\0' */ | |
931 | ||
932 | host = inet_ntoa(s4_req.dest_addr); | |
933 | strlcpy(c->path, host, sizeof(c->path)); | |
934 | c->host_port = ntohs(s4_req.dest_port); | |
935 | ||
936 | debug("channel %d: dynamic request: socks4 host %s port %u command %u", | |
937 | c->self, host, c->host_port, s4_req.command); | |
938 | ||
939 | if (s4_req.command != 1) { | |
940 | debug("channel %d: cannot handle: socks4 cn %d", | |
941 | c->self, s4_req.command); | |
942 | return -1; | |
943 | } | |
944 | s4_rsp.version = 0; /* vn: 0 for reply */ | |
945 | s4_rsp.command = 90; /* cd: req granted */ | |
946 | s4_rsp.dest_port = 0; /* ignored */ | |
947 | s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */ | |
948 | buffer_append(&c->output, (char *)&s4_rsp, sizeof(s4_rsp)); | |
949 | return 1; | |
950 | } | |
951 | ||
952 | /* dynamic port forwarding */ | |
953 | static void | |
954 | channel_pre_dynamic(Channel *c, fd_set * readset, fd_set * writeset) | |
955 | { | |
956 | u_char *p; | |
957 | int have, ret; | |
958 | ||
959 | have = buffer_len(&c->input); | |
960 | c->delayed = 0; | |
961 | debug2("channel %d: pre_dynamic: have %d", c->self, have); | |
962 | /* buffer_dump(&c->input); */ | |
963 | /* check if the fixed size part of the packet is in buffer. */ | |
964 | if (have < 4) { | |
965 | /* need more */ | |
966 | FD_SET(c->sock, readset); | |
967 | return; | |
968 | } | |
969 | /* try to guess the protocol */ | |
970 | p = buffer_ptr(&c->input); | |
971 | switch (p[0]) { | |
972 | case 0x04: | |
973 | ret = channel_decode_socks4(c, readset, writeset); | |
974 | break; | |
975 | default: | |
976 | ret = -1; | |
977 | break; | |
978 | } | |
979 | if (ret < 0) { | |
980 | chan_mark_dead(c); | |
981 | } else if (ret == 0) { | |
982 | debug2("channel %d: pre_dynamic: need more", c->self); | |
983 | /* need more */ | |
984 | FD_SET(c->sock, readset); | |
985 | } else { | |
986 | /* switch to the next state */ | |
987 | c->type = SSH_CHANNEL_OPENING; | |
988 | port_open_helper(c, "direct-tcpip"); | |
989 | } | |
990 | } | |
991 | ||
992 | /* This is our fake X11 server socket. */ | |
993 | static void | |
994 | channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset) | |
995 | { | |
996 | Channel *nc; | |
997 | struct sockaddr addr; | |
998 | int newsock, on = 1; | |
999 | socklen_t addrlen; | |
1000 | char buf[16384], *remote_ipaddr; | |
1001 | int remote_port; | |
1002 | ||
1003 | if (FD_ISSET(c->sock, readset)) { | |
1004 | debug("X11 connection requested."); | |
1005 | addrlen = sizeof(addr); | |
1006 | newsock = accept(c->sock, &addr, &addrlen); | |
1007 | if (c->single_connection) { | |
1008 | debug("single_connection: closing X11 listener."); | |
1009 | channel_close_fd(&c->sock); | |
1010 | chan_mark_dead(c); | |
1011 | } | |
1012 | if (newsock < 0) { | |
1013 | error("accept: %.100s", strerror(errno)); | |
1014 | return; | |
1015 | } | |
1016 | if (setsockopt(newsock, IPPROTO_TCP, TCP_NODELAY, &on, | |
1017 | sizeof on) == -1) | |
1018 | error("setsockopt TCP_NODELAY: %.100s", | |
1019 | strerror(errno)); | |
1020 | remote_ipaddr = get_peer_ipaddr(newsock); | |
1021 | remote_port = get_peer_port(newsock); | |
1022 | snprintf(buf, sizeof buf, "X11 connection from %.200s port %d", | |
1023 | remote_ipaddr, remote_port); | |
1024 | ||
1025 | nc = channel_new("accepted x11 socket", | |
1026 | SSH_CHANNEL_OPENING, newsock, newsock, -1, | |
1027 | c->local_window_max, c->local_maxpacket, | |
1028 | 0, xstrdup(buf), 1); | |
1029 | if (nc == NULL) { | |
1030 | close(newsock); | |
1031 | xfree(remote_ipaddr); | |
1032 | return; | |
1033 | } | |
1034 | if (compat20) { | |
1035 | packet_start(SSH2_MSG_CHANNEL_OPEN); | |
1036 | packet_put_cstring("x11"); | |
1037 | packet_put_int(nc->self); | |
1038 | packet_put_int(nc->local_window_max); | |
1039 | packet_put_int(nc->local_maxpacket); | |
1040 | /* originator ipaddr and port */ | |
1041 | packet_put_cstring(remote_ipaddr); | |
1042 | if (datafellows & SSH_BUG_X11FWD) { | |
1043 | debug("ssh2 x11 bug compat mode"); | |
1044 | } else { | |
1045 | packet_put_int(remote_port); | |
1046 | } | |
1047 | packet_send(); | |
1048 | } else { | |
1049 | packet_start(SSH_SMSG_X11_OPEN); | |
1050 | packet_put_int(nc->self); | |
1051 | if (packet_get_protocol_flags() & | |
1052 | SSH_PROTOFLAG_HOST_IN_FWD_OPEN) | |
1053 | packet_put_cstring(buf); | |
1054 | packet_send(); | |
1055 | } | |
1056 | xfree(remote_ipaddr); | |
1057 | } | |
1058 | } | |
1059 | ||
1060 | static void | |
1061 | port_open_helper(Channel *c, char *rtype) | |
1062 | { | |
1063 | int direct; | |
1064 | char buf[1024]; | |
1065 | char *remote_ipaddr = get_peer_ipaddr(c->sock); | |
1066 | u_short remote_port = get_peer_port(c->sock); | |
1067 | ||
1068 | direct = (strcmp(rtype, "direct-tcpip") == 0); | |
1069 | ||
1070 | snprintf(buf, sizeof buf, | |
1071 | "%s: listening port %d for %.100s port %d, " | |
1072 | "connect from %.200s port %d", | |
1073 | rtype, c->listening_port, c->path, c->host_port, | |
1074 | remote_ipaddr, remote_port); | |
1075 | ||
1076 | xfree(c->remote_name); | |
1077 | c->remote_name = xstrdup(buf); | |
1078 | ||
1079 | if (compat20) { | |
1080 | packet_start(SSH2_MSG_CHANNEL_OPEN); | |
1081 | packet_put_cstring(rtype); | |
1082 | packet_put_int(c->self); | |
1083 | packet_put_int(c->local_window_max); | |
1084 | packet_put_int(c->local_maxpacket); | |
1085 | if (direct) { | |
1086 | /* target host, port */ | |
1087 | packet_put_cstring(c->path); | |
1088 | packet_put_int(c->host_port); | |
1089 | } else { | |
1090 | /* listen address, port */ | |
1091 | packet_put_cstring(c->path); | |
1092 | packet_put_int(c->listening_port); | |
1093 | } | |
1094 | /* originator host and port */ | |
1095 | packet_put_cstring(remote_ipaddr); | |
1096 | packet_put_int(remote_port); | |
1097 | packet_send(); | |
1098 | } else { | |
1099 | packet_start(SSH_MSG_PORT_OPEN); | |
1100 | packet_put_int(c->self); | |
1101 | packet_put_cstring(c->path); | |
1102 | packet_put_int(c->host_port); | |
1103 | if (packet_get_protocol_flags() & | |
1104 | SSH_PROTOFLAG_HOST_IN_FWD_OPEN) | |
1105 | packet_put_cstring(c->remote_name); | |
1106 | packet_send(); | |
1107 | } | |
1108 | xfree(remote_ipaddr); | |
1109 | } | |
1110 | ||
1111 | /* | |
1112 | * This socket is listening for connections to a forwarded TCP/IP port. | |
1113 | */ | |
1114 | static void | |
1115 | channel_post_port_listener(Channel *c, fd_set * readset, fd_set * writeset) | |
1116 | { | |
1117 | Channel *nc; | |
1118 | struct sockaddr addr; | |
1119 | int newsock, nextstate; | |
1120 | socklen_t addrlen; | |
1121 | char *rtype; | |
1122 | ||
1123 | if (FD_ISSET(c->sock, readset)) { | |
1124 | debug("Connection to port %d forwarding " | |
1125 | "to %.100s port %d requested.", | |
1126 | c->listening_port, c->path, c->host_port); | |
1127 | ||
1128 | if (c->type == SSH_CHANNEL_RPORT_LISTENER) { | |
1129 | nextstate = SSH_CHANNEL_OPENING; | |
1130 | rtype = "forwarded-tcpip"; | |
1131 | } else { | |
1132 | if (c->host_port == 0) { | |
1133 | nextstate = SSH_CHANNEL_DYNAMIC; | |
1134 | rtype = "dynamic-tcpip"; | |
1135 | } else { | |
1136 | nextstate = SSH_CHANNEL_OPENING; | |
1137 | rtype = "direct-tcpip"; | |
1138 | } | |
1139 | } | |
1140 | ||
1141 | addrlen = sizeof(addr); | |
1142 | newsock = accept(c->sock, &addr, &addrlen); | |
1143 | if (newsock < 0) { | |
1144 | error("accept: %.100s", strerror(errno)); | |
1145 | return; | |
1146 | } | |
1147 | nc = channel_new(rtype, | |
1148 | nextstate, newsock, newsock, -1, | |
1149 | c->local_window_max, c->local_maxpacket, | |
1150 | 0, xstrdup(rtype), 1); | |
1151 | if (nc == NULL) { | |
1152 | error("channel_post_port_listener: no new channel:"); | |
1153 | close(newsock); | |
1154 | return; | |
1155 | } | |
1156 | nc->listening_port = c->listening_port; | |
1157 | nc->host_port = c->host_port; | |
1158 | strlcpy(nc->path, c->path, sizeof(nc->path)); | |
1159 | ||
1160 | if (nextstate == SSH_CHANNEL_DYNAMIC) { | |
1161 | /* | |
1162 | * do not call the channel_post handler until | |
1163 | * this flag has been reset by a pre-handler. | |
1164 | * otherwise the FD_ISSET calls might overflow | |
1165 | */ | |
1166 | nc->delayed = 1; | |
1167 | } else { | |
1168 | port_open_helper(nc, rtype); | |
1169 | } | |
1170 | } | |
1171 | } | |
1172 | ||
1173 | /* | |
1174 | * This is the authentication agent socket listening for connections from | |
1175 | * clients. | |
1176 | */ | |
1177 | static void | |
1178 | channel_post_auth_listener(Channel *c, fd_set * readset, fd_set * writeset) | |
1179 | { | |
1180 | Channel *nc; | |
1181 | char *name; | |
1182 | int newsock; | |
1183 | struct sockaddr addr; | |
1184 | socklen_t addrlen; | |
1185 | ||
1186 | if (FD_ISSET(c->sock, readset)) { | |
1187 | addrlen = sizeof(addr); | |
1188 | newsock = accept(c->sock, &addr, &addrlen); | |
1189 | if (newsock < 0) { | |
1190 | error("accept from auth socket: %.100s", strerror(errno)); | |
1191 | return; | |
1192 | } | |
1193 | name = xstrdup("accepted auth socket"); | |
1194 | nc = channel_new("accepted auth socket", | |
1195 | SSH_CHANNEL_OPENING, newsock, newsock, -1, | |
1196 | c->local_window_max, c->local_maxpacket, | |
1197 | 0, name, 1); | |
1198 | if (nc == NULL) { | |
1199 | error("channel_post_auth_listener: channel_new failed"); | |
1200 | xfree(name); | |
1201 | close(newsock); | |
1202 | } | |
1203 | if (compat20) { | |
1204 | packet_start(SSH2_MSG_CHANNEL_OPEN); | |
1205 | packet_put_cstring("auth-agent@openssh.com"); | |
1206 | packet_put_int(nc->self); | |
1207 | packet_put_int(c->local_window_max); | |
1208 | packet_put_int(c->local_maxpacket); | |
1209 | } else { | |
1210 | packet_start(SSH_SMSG_AGENT_OPEN); | |
1211 | packet_put_int(nc->self); | |
1212 | } | |
1213 | packet_send(); | |
1214 | } | |
1215 | } | |
1216 | ||
1217 | static void | |
1218 | channel_post_connecting(Channel *c, fd_set * readset, fd_set * writeset) | |
1219 | { | |
1220 | int err = 0; | |
1221 | socklen_t sz = sizeof(err); | |
1222 | ||
1223 | if (FD_ISSET(c->sock, writeset)) { | |
1224 | if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, (char *)&err, | |
1225 | &sz) < 0) { | |
1226 | err = errno; | |
1227 | error("getsockopt SO_ERROR failed"); | |
1228 | } | |
1229 | if (err == 0) { | |
1230 | debug("channel %d: connected", c->self); | |
1231 | c->type = SSH_CHANNEL_OPEN; | |
1232 | if (compat20) { | |
1233 | packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION); | |
1234 | packet_put_int(c->remote_id); | |
1235 | packet_put_int(c->self); | |
1236 | packet_put_int(c->local_window); | |
1237 | packet_put_int(c->local_maxpacket); | |
1238 | } else { | |
1239 | packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION); | |
1240 | packet_put_int(c->remote_id); | |
1241 | packet_put_int(c->self); | |
1242 | } | |
1243 | } else { | |
1244 | debug("channel %d: not connected: %s", | |
1245 | c->self, strerror(err)); | |
1246 | if (compat20) { | |
1247 | packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE); | |
1248 | packet_put_int(c->remote_id); | |
1249 | packet_put_int(SSH2_OPEN_CONNECT_FAILED); | |
1250 | if (!(datafellows & SSH_BUG_OPENFAILURE)) { | |
1251 | packet_put_cstring(strerror(err)); | |
1252 | packet_put_cstring(""); | |
1253 | } | |
1254 | } else { | |
1255 | packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); | |
1256 | packet_put_int(c->remote_id); | |
1257 | } | |
1258 | chan_mark_dead(c); | |
1259 | } | |
1260 | packet_send(); | |
1261 | } | |
1262 | } | |
1263 | ||
1264 | static int | |
1265 | channel_handle_rfd(Channel *c, fd_set * readset, fd_set * writeset) | |
1266 | { | |
1267 | char buf[16*1024]; | |
1268 | int len; | |
1269 | ||
1270 | if (c->rfd != -1 && | |
1271 | FD_ISSET(c->rfd, readset)) { | |
1272 | len = read(c->rfd, buf, sizeof(buf)); | |
1273 | if (len < 0 && (errno == EINTR || errno == EAGAIN)) | |
1274 | return 1; | |
1275 | if (len <= 0) { | |
1276 | debug("channel %d: read<=0 rfd %d len %d", | |
1277 | c->self, c->rfd, len); | |
1278 | if (c->type != SSH_CHANNEL_OPEN) { | |
1279 | debug("channel %d: not open", c->self); | |
1280 | chan_mark_dead(c); | |
1281 | return -1; | |
1282 | } else if (compat13) { | |
1283 | buffer_consume(&c->output, buffer_len(&c->output)); | |
1284 | c->type = SSH_CHANNEL_INPUT_DRAINING; | |
1285 | debug("channel %d: input draining.", c->self); | |
1286 | } else { | |
1287 | chan_read_failed(c); | |
1288 | } | |
1289 | return -1; | |
1290 | } | |
1291 | if (c->input_filter != NULL) { | |
1292 | if (c->input_filter(c, buf, len) == -1) { | |
1293 | debug("channel %d: filter stops", c->self); | |
1294 | chan_read_failed(c); | |
1295 | } | |
1296 | } else { | |
1297 | buffer_append(&c->input, buf, len); | |
1298 | } | |
1299 | } | |
1300 | return 1; | |
1301 | } | |
1302 | static int | |
1303 | channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset) | |
1304 | { | |
1305 | struct termios tio; | |
1306 | u_char *data; | |
1307 | u_int dlen; | |
1308 | int len; | |
1309 | ||
1310 | /* Send buffered output data to the socket. */ | |
1311 | if (c->wfd != -1 && | |
1312 | FD_ISSET(c->wfd, writeset) && | |
1313 | buffer_len(&c->output) > 0) { | |
1314 | data = buffer_ptr(&c->output); | |
1315 | dlen = buffer_len(&c->output); | |
1316 | len = write(c->wfd, data, dlen); | |
1317 | if (len < 0 && (errno == EINTR || errno == EAGAIN)) | |
1318 | return 1; | |
1319 | if (len <= 0) { | |
1320 | if (c->type != SSH_CHANNEL_OPEN) { | |
1321 | debug("channel %d: not open", c->self); | |
1322 | chan_mark_dead(c); | |
1323 | return -1; | |
1324 | } else if (compat13) { | |
1325 | buffer_consume(&c->output, buffer_len(&c->output)); | |
1326 | debug("channel %d: input draining.", c->self); | |
1327 | c->type = SSH_CHANNEL_INPUT_DRAINING; | |
1328 | } else { | |
1329 | chan_write_failed(c); | |
1330 | } | |
1331 | return -1; | |
1332 | } | |
1333 | if (compat20 && c->isatty && dlen >= 1 && data[0] != '\r') { | |
1334 | if (tcgetattr(c->wfd, &tio) == 0 && | |
1335 | !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) { | |
1336 | /* | |
1337 | * Simulate echo to reduce the impact of | |
1338 | * traffic analysis. We need to match the | |
1339 | * size of a SSH2_MSG_CHANNEL_DATA message | |
1340 | * (4 byte channel id + data) | |
1341 | */ | |
1342 | packet_send_ignore(4 + len); | |
1343 | packet_send(); | |
1344 | } | |
1345 | } | |
1346 | buffer_consume(&c->output, len); | |
1347 | if (compat20 && len > 0) { | |
1348 | c->local_consumed += len; | |
1349 | } | |
1350 | } | |
1351 | return 1; | |
1352 | } | |
1353 | static int | |
1354 | channel_handle_efd(Channel *c, fd_set * readset, fd_set * writeset) | |
1355 | { | |
1356 | char buf[16*1024]; | |
1357 | int len; | |
1358 | ||
1359 | /** XXX handle drain efd, too */ | |
1360 | if (c->efd != -1) { | |
1361 | if (c->extended_usage == CHAN_EXTENDED_WRITE && | |
1362 | FD_ISSET(c->efd, writeset) && | |
1363 | buffer_len(&c->extended) > 0) { | |
1364 | len = write(c->efd, buffer_ptr(&c->extended), | |
1365 | buffer_len(&c->extended)); | |
1366 | debug2("channel %d: written %d to efd %d", | |
1367 | c->self, len, c->efd); | |
1368 | if (len < 0 && (errno == EINTR || errno == EAGAIN)) | |
1369 | return 1; | |
1370 | if (len <= 0) { | |
1371 | debug2("channel %d: closing write-efd %d", | |
1372 | c->self, c->efd); | |
1373 | channel_close_fd(&c->efd); | |
1374 | } else { | |
1375 | buffer_consume(&c->extended, len); | |
1376 | c->local_consumed += len; | |
1377 | } | |
1378 | } else if (c->extended_usage == CHAN_EXTENDED_READ && | |
1379 | FD_ISSET(c->efd, readset)) { | |
1380 | len = read(c->efd, buf, sizeof(buf)); | |
1381 | debug2("channel %d: read %d from efd %d", | |
1382 | c->self, len, c->efd); | |
1383 | if (len < 0 && (errno == EINTR || errno == EAGAIN)) | |
1384 | return 1; | |
1385 | if (len <= 0) { | |
1386 | debug2("channel %d: closing read-efd %d", | |
1387 | c->self, c->efd); | |
1388 | channel_close_fd(&c->efd); | |
1389 | } else { | |
1390 | buffer_append(&c->extended, buf, len); | |
1391 | } | |
1392 | } | |
1393 | } | |
1394 | return 1; | |
1395 | } | |
1396 | static int | |
1397 | channel_check_window(Channel *c) | |
1398 | { | |
1399 | if (c->type == SSH_CHANNEL_OPEN && | |
1400 | !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) && | |
1401 | c->local_window < c->local_window_max/2 && | |
1402 | c->local_consumed > 0) { | |
1403 | packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST); | |
1404 | packet_put_int(c->remote_id); | |
1405 | packet_put_int(c->local_consumed); | |
1406 | packet_send(); | |
1407 | debug2("channel %d: window %d sent adjust %d", | |
1408 | c->self, c->local_window, | |
1409 | c->local_consumed); | |
1410 | c->local_window += c->local_consumed; | |
1411 | c->local_consumed = 0; | |
1412 | } | |
1413 | return 1; | |
1414 | } | |
1415 | ||
1416 | static void | |
1417 | channel_post_open_1(Channel *c, fd_set * readset, fd_set * writeset) | |
1418 | { | |
1419 | if (c->delayed) | |
1420 | return; | |
1421 | channel_handle_rfd(c, readset, writeset); | |
1422 | channel_handle_wfd(c, readset, writeset); | |
1423 | } | |
1424 | ||
1425 | static void | |
1426 | channel_post_open_2(Channel *c, fd_set * readset, fd_set * writeset) | |
1427 | { | |
1428 | if (c->delayed) | |
1429 | return; | |
1430 | channel_handle_rfd(c, readset, writeset); | |
1431 | channel_handle_wfd(c, readset, writeset); | |
1432 | channel_handle_efd(c, readset, writeset); | |
1433 | ||
1434 | channel_check_window(c); | |
1435 | } | |
1436 | ||
1437 | static void | |
1438 | channel_post_output_drain_13(Channel *c, fd_set * readset, fd_set * writeset) | |
1439 | { | |
1440 | int len; | |
1441 | /* Send buffered output data to the socket. */ | |
1442 | if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) { | |
1443 | len = write(c->sock, buffer_ptr(&c->output), | |
1444 | buffer_len(&c->output)); | |
1445 | if (len <= 0) | |
1446 | buffer_consume(&c->output, buffer_len(&c->output)); | |
1447 | else | |
1448 | buffer_consume(&c->output, len); | |
1449 | } | |
1450 | } | |
1451 | ||
1452 | static void | |
1453 | channel_handler_init_20(void) | |
1454 | { | |
1455 | channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_20; | |
1456 | channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; | |
1457 | channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; | |
1458 | channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener; | |
1459 | channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; | |
1460 | channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; | |
1461 | channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; | |
1462 | channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; | |
1463 | ||
1464 | channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_2; | |
1465 | channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; | |
1466 | channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener; | |
1467 | channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; | |
1468 | channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; | |
1469 | channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; | |
1470 | channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open_2; | |
1471 | } | |
1472 | ||
1473 | static void | |
1474 | channel_handler_init_13(void) | |
1475 | { | |
1476 | channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13; | |
1477 | channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13; | |
1478 | channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; | |
1479 | channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; | |
1480 | channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; | |
1481 | channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining; | |
1482 | channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining; | |
1483 | channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; | |
1484 | channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; | |
1485 | ||
1486 | channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_1; | |
1487 | channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; | |
1488 | channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; | |
1489 | channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; | |
1490 | channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13; | |
1491 | channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; | |
1492 | channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open_1; | |
1493 | } | |
1494 | ||
1495 | static void | |
1496 | channel_handler_init_15(void) | |
1497 | { | |
1498 | channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_15; | |
1499 | channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; | |
1500 | channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; | |
1501 | channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; | |
1502 | channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; | |
1503 | channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; | |
1504 | channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; | |
1505 | ||
1506 | channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; | |
1507 | channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; | |
1508 | channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; | |
1509 | channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_1; | |
1510 | channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; | |
1511 | channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open_1; | |
1512 | } | |
1513 | ||
1514 | static void | |
1515 | channel_handler_init(void) | |
1516 | { | |
1517 | int i; | |
1518 | for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) { | |
1519 | channel_pre[i] = NULL; | |
1520 | channel_post[i] = NULL; | |
1521 | } | |
1522 | if (compat20) | |
1523 | channel_handler_init_20(); | |
1524 | else if (compat13) | |
1525 | channel_handler_init_13(); | |
1526 | else | |
1527 | channel_handler_init_15(); | |
1528 | } | |
1529 | ||
1530 | /* gc dead channels */ | |
1531 | static void | |
1532 | channel_garbage_collect(Channel *c) | |
1533 | { | |
1534 | if (c == NULL) | |
1535 | return; | |
1536 | if (c->detach_user != NULL) { | |
1537 | if (!chan_is_dead(c, 0)) | |
1538 | return; | |
1539 | debug("channel %d: gc: notify user", c->self); | |
1540 | c->detach_user(c->self, NULL); | |
1541 | /* if we still have a callback */ | |
1542 | if (c->detach_user != NULL) | |
1543 | return; | |
1544 | debug("channel %d: gc: user detached", c->self); | |
1545 | } | |
1546 | if (!chan_is_dead(c, 1)) | |
1547 | return; | |
1548 | debug("channel %d: garbage collecting", c->self); | |
1549 | channel_free(c); | |
1550 | } | |
1551 | ||
1552 | static void | |
1553 | channel_handler(chan_fn *ftab[], fd_set * readset, fd_set * writeset) | |
1554 | { | |
1555 | static int did_init = 0; | |
1556 | int i; | |
1557 | Channel *c; | |
1558 | ||
1559 | if (!did_init) { | |
1560 | channel_handler_init(); | |
1561 | did_init = 1; | |
1562 | } | |
1563 | for (i = 0; i < channels_alloc; i++) { | |
1564 | c = channels[i]; | |
1565 | if (c == NULL) | |
1566 | continue; | |
1567 | if (ftab[c->type] != NULL) | |
1568 | (*ftab[c->type])(c, readset, writeset); | |
1569 | channel_garbage_collect(c); | |
1570 | } | |
1571 | } | |
1572 | ||
1573 | /* | |
1574 | * Allocate/update select bitmasks and add any bits relevant to channels in | |
1575 | * select bitmasks. | |
1576 | */ | |
1577 | void | |
1578 | channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp, | |
1579 | int *nallocp, int rekeying) | |
1580 | { | |
1581 | int n; | |
1582 | u_int sz; | |
1583 | ||
1584 | n = MAX(*maxfdp, channel_max_fd); | |
1585 | ||
1586 | sz = howmany(n+1, NFDBITS) * sizeof(fd_mask); | |
1587 | /* perhaps check sz < nalloc/2 and shrink? */ | |
1588 | if (*readsetp == NULL || sz > *nallocp) { | |
1589 | *readsetp = xrealloc(*readsetp, sz); | |
1590 | *writesetp = xrealloc(*writesetp, sz); | |
1591 | *nallocp = sz; | |
1592 | } | |
1593 | *maxfdp = n; | |
1594 | memset(*readsetp, 0, sz); | |
1595 | memset(*writesetp, 0, sz); | |
1596 | ||
1597 | if (!rekeying) | |
1598 | channel_handler(channel_pre, *readsetp, *writesetp); | |
1599 | } | |
1600 | ||
1601 | /* | |
1602 | * After select, perform any appropriate operations for channels which have | |
1603 | * events pending. | |
1604 | */ | |
1605 | void | |
1606 | channel_after_select(fd_set * readset, fd_set * writeset) | |
1607 | { | |
1608 | channel_handler(channel_post, readset, writeset); | |
1609 | } | |
1610 | ||
1611 | ||
1612 | /* If there is data to send to the connection, enqueue some of it now. */ | |
1613 | ||
1614 | void | |
1615 | channel_output_poll(void) | |
1616 | { | |
1617 | int len, i; | |
1618 | Channel *c; | |
1619 | ||
1620 | for (i = 0; i < channels_alloc; i++) { | |
1621 | c = channels[i]; | |
1622 | if (c == NULL) | |
1623 | continue; | |
1624 | ||
1625 | /* | |
1626 | * We are only interested in channels that can have buffered | |
1627 | * incoming data. | |
1628 | */ | |
1629 | if (compat13) { | |
1630 | if (c->type != SSH_CHANNEL_OPEN && | |
1631 | c->type != SSH_CHANNEL_INPUT_DRAINING) | |
1632 | continue; | |
1633 | } else { | |
1634 | if (c->type != SSH_CHANNEL_OPEN) | |
1635 | continue; | |
1636 | } | |
1637 | if (compat20 && | |
1638 | (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) { | |
1639 | /* XXX is this true? */ | |
1640 | debug3("channel %d: will not send data after close", c->self); | |
1641 | continue; | |
1642 | } | |
1643 | ||
1644 | /* Get the amount of buffered data for this channel. */ | |
1645 | if ((c->istate == CHAN_INPUT_OPEN || | |
1646 | c->istate == CHAN_INPUT_WAIT_DRAIN) && | |
1647 | (len = buffer_len(&c->input)) > 0) { | |
1648 | /* | |
1649 | * Send some data for the other side over the secure | |
1650 | * connection. | |
1651 | */ | |
1652 | if (compat20) { | |
1653 | if (len > c->remote_window) | |
1654 | len = c->remote_window; | |
1655 | if (len > c->remote_maxpacket) | |
1656 | len = c->remote_maxpacket; | |
1657 | } else { | |
1658 | if (packet_is_interactive()) { | |
1659 | if (len > 1024) | |
1660 | len = 512; | |
1661 | } else { | |
1662 | /* Keep the packets at reasonable size. */ | |
1663 | if (len > packet_get_maxsize()/2) | |
1664 | len = packet_get_maxsize()/2; | |
1665 | } | |
1666 | } | |
1667 | if (len > 0) { | |
1668 | packet_start(compat20 ? | |
1669 | SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA); | |
1670 | packet_put_int(c->remote_id); | |
1671 | packet_put_string(buffer_ptr(&c->input), len); | |
1672 | packet_send(); | |
1673 | buffer_consume(&c->input, len); | |
1674 | c->remote_window -= len; | |
1675 | } | |
1676 | } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) { | |
1677 | if (compat13) | |
1678 | fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3"); | |
1679 | /* | |
1680 | * input-buffer is empty and read-socket shutdown: | |
1681 | * tell peer, that we will not send more data: send IEOF | |
1682 | */ | |
1683 | chan_ibuf_empty(c); | |
1684 | } | |
1685 | /* Send extended data, i.e. stderr */ | |
1686 | if (compat20 && | |
1687 | c->remote_window > 0 && | |
1688 | (len = buffer_len(&c->extended)) > 0 && | |
1689 | c->extended_usage == CHAN_EXTENDED_READ) { | |
1690 | debug2("channel %d: rwin %d elen %d euse %d", | |
1691 | c->self, c->remote_window, buffer_len(&c->extended), | |
1692 | c->extended_usage); | |
1693 | if (len > c->remote_window) | |
1694 | len = c->remote_window; | |
1695 | if (len > c->remote_maxpacket) | |
1696 | len = c->remote_maxpacket; | |
1697 | packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA); | |
1698 | packet_put_int(c->remote_id); | |
1699 | packet_put_int(SSH2_EXTENDED_DATA_STDERR); | |
1700 | packet_put_string(buffer_ptr(&c->extended), len); | |
1701 | packet_send(); | |
1702 | buffer_consume(&c->extended, len); | |
1703 | c->remote_window -= len; | |
1704 | debug2("channel %d: sent ext data %d", c->self, len); | |
1705 | } | |
1706 | } | |
1707 | } | |
1708 | ||
1709 | ||
1710 | /* -- protocol input */ | |
1711 | ||
1712 | void | |
1713 | channel_input_data(int type, int plen, u_int32_t seq, void *ctxt) | |
1714 | { | |
1715 | int id; | |
1716 | char *data; | |
1717 | u_int data_len; | |
1718 | Channel *c; | |
1719 | ||
1720 | /* Get the channel number and verify it. */ | |
1721 | id = packet_get_int(); | |
1722 | c = channel_lookup(id); | |
1723 | if (c == NULL) | |
1724 | packet_disconnect("Received data for nonexistent channel %d.", id); | |
1725 | ||
1726 | /* Ignore any data for non-open channels (might happen on close) */ | |
1727 | if (c->type != SSH_CHANNEL_OPEN && | |
1728 | c->type != SSH_CHANNEL_X11_OPEN) | |
1729 | return; | |
1730 | ||
1731 | /* same for protocol 1.5 if output end is no longer open */ | |
1732 | if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) | |
1733 | return; | |
1734 | ||
1735 | /* Get the data. */ | |
1736 | data = packet_get_string(&data_len); | |
1737 | packet_done(); | |
1738 | ||
1739 | if (compat20) { | |
1740 | if (data_len > c->local_maxpacket) { | |
1741 | log("channel %d: rcvd big packet %d, maxpack %d", | |
1742 | c->self, data_len, c->local_maxpacket); | |
1743 | } | |
1744 | if (data_len > c->local_window) { | |
1745 | log("channel %d: rcvd too much data %d, win %d", | |
1746 | c->self, data_len, c->local_window); | |
1747 | xfree(data); | |
1748 | return; | |
1749 | } | |
1750 | c->local_window -= data_len; | |
1751 | }else{ | |
1752 | packet_integrity_check(plen, 4 + 4 + data_len, type); | |
1753 | } | |
1754 | buffer_append(&c->output, data, data_len); | |
1755 | xfree(data); | |
1756 | } | |
1757 | ||
1758 | void | |
1759 | channel_input_extended_data(int type, int plen, u_int32_t seq, void *ctxt) | |
1760 | { | |
1761 | int id; | |
1762 | int tcode; | |
1763 | char *data; | |
1764 | u_int data_len; | |
1765 | Channel *c; | |
1766 | ||
1767 | /* Get the channel number and verify it. */ | |
1768 | id = packet_get_int(); | |
1769 | c = channel_lookup(id); | |
1770 | ||
1771 | if (c == NULL) | |
1772 | packet_disconnect("Received extended_data for bad channel %d.", id); | |
1773 | if (c->type != SSH_CHANNEL_OPEN) { | |
1774 | log("channel %d: ext data for non open", id); | |
1775 | return; | |
1776 | } | |
1777 | tcode = packet_get_int(); | |
1778 | if (c->efd == -1 || | |
1779 | c->extended_usage != CHAN_EXTENDED_WRITE || | |
1780 | tcode != SSH2_EXTENDED_DATA_STDERR) { | |
1781 | log("channel %d: bad ext data", c->self); | |
1782 | return; | |
1783 | } | |
1784 | data = packet_get_string(&data_len); | |
1785 | packet_done(); | |
1786 | if (data_len > c->local_window) { | |
1787 | log("channel %d: rcvd too much extended_data %d, win %d", | |
1788 | c->self, data_len, c->local_window); | |
1789 | xfree(data); | |
1790 | return; | |
1791 | } | |
1792 | debug2("channel %d: rcvd ext data %d", c->self, data_len); | |
1793 | c->local_window -= data_len; | |
1794 | buffer_append(&c->extended, data, data_len); | |
1795 | xfree(data); | |
1796 | } | |
1797 | ||
1798 | void | |
1799 | channel_input_ieof(int type, int plen, u_int32_t seq, void *ctxt) | |
1800 | { | |
1801 | int id; | |
1802 | Channel *c; | |
1803 | ||
1804 | packet_integrity_check(plen, 4, type); | |
1805 | ||
1806 | id = packet_get_int(); | |
1807 | c = channel_lookup(id); | |
1808 | if (c == NULL) | |
1809 | packet_disconnect("Received ieof for nonexistent channel %d.", id); | |
1810 | chan_rcvd_ieof(c); | |
1811 | ||
1812 | /* XXX force input close */ | |
1813 | if (c->force_drain) { | |
1814 | debug("channel %d: FORCE input drain", c->self); | |
1815 | c->istate = CHAN_INPUT_WAIT_DRAIN; | |
1816 | } | |
1817 | ||
1818 | } | |
1819 | ||
1820 | void | |
1821 | channel_input_close(int type, int plen, u_int32_t seq, void *ctxt) | |
1822 | { | |
1823 | int id; | |
1824 | Channel *c; | |
1825 | ||
1826 | packet_integrity_check(plen, 4, type); | |
1827 | ||
1828 | id = packet_get_int(); | |
1829 | c = channel_lookup(id); | |
1830 | if (c == NULL) | |
1831 | packet_disconnect("Received close for nonexistent channel %d.", id); | |
1832 | ||
1833 | /* | |
1834 | * Send a confirmation that we have closed the channel and no more | |
1835 | * data is coming for it. | |
1836 | */ | |
1837 | packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION); | |
1838 | packet_put_int(c->remote_id); | |
1839 | packet_send(); | |
1840 | ||
1841 | /* | |
1842 | * If the channel is in closed state, we have sent a close request, | |
1843 | * and the other side will eventually respond with a confirmation. | |
1844 | * Thus, we cannot free the channel here, because then there would be | |
1845 | * no-one to receive the confirmation. The channel gets freed when | |
1846 | * the confirmation arrives. | |
1847 | */ | |
1848 | if (c->type != SSH_CHANNEL_CLOSED) { | |
1849 | /* | |
1850 | * Not a closed channel - mark it as draining, which will | |
1851 | * cause it to be freed later. | |
1852 | */ | |
1853 | buffer_consume(&c->input, buffer_len(&c->input)); | |
1854 | c->type = SSH_CHANNEL_OUTPUT_DRAINING; | |
1855 | } | |
1856 | } | |
1857 | ||
1858 | /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */ | |
1859 | void | |
1860 | channel_input_oclose(int type, int plen, u_int32_t seq, void *ctxt) | |
1861 | { | |
1862 | int id = packet_get_int(); | |
1863 | Channel *c = channel_lookup(id); | |
1864 | packet_integrity_check(plen, 4, type); | |
1865 | if (c == NULL) | |
1866 | packet_disconnect("Received oclose for nonexistent channel %d.", id); | |
1867 | chan_rcvd_oclose(c); | |
1868 | } | |
1869 | ||
1870 | void | |
1871 | channel_input_close_confirmation(int type, int plen, u_int32_t seq, void *ctxt) | |
1872 | { | |
1873 | int id = packet_get_int(); | |
1874 | Channel *c = channel_lookup(id); | |
1875 | ||
1876 | packet_done(); | |
1877 | if (c == NULL) | |
1878 | packet_disconnect("Received close confirmation for " | |
1879 | "out-of-range channel %d.", id); | |
1880 | if (c->type != SSH_CHANNEL_CLOSED) | |
1881 | packet_disconnect("Received close confirmation for " | |
1882 | "non-closed channel %d (type %d).", id, c->type); | |
1883 | channel_free(c); | |
1884 | } | |
1885 | ||
1886 | void | |
1887 | channel_input_open_confirmation(int type, int plen, u_int32_t seq, void *ctxt) | |
1888 | { | |
1889 | int id, remote_id; | |
1890 | Channel *c; | |
1891 | ||
1892 | if (!compat20) | |
1893 | packet_integrity_check(plen, 4 + 4, type); | |
1894 | ||
1895 | id = packet_get_int(); | |
1896 | c = channel_lookup(id); | |
1897 | ||
1898 | if (c==NULL || c->type != SSH_CHANNEL_OPENING) | |
1899 | packet_disconnect("Received open confirmation for " | |
1900 | "non-opening channel %d.", id); | |
1901 | remote_id = packet_get_int(); | |
1902 | /* Record the remote channel number and mark that the channel is now open. */ | |
1903 | c->remote_id = remote_id; | |
1904 | c->type = SSH_CHANNEL_OPEN; | |
1905 | ||
1906 | if (compat20) { | |
1907 | c->remote_window = packet_get_int(); | |
1908 | c->remote_maxpacket = packet_get_int(); | |
1909 | packet_done(); | |
1910 | if (c->cb_fn != NULL && c->cb_event == type) { | |
1911 | debug2("callback start"); | |
1912 | c->cb_fn(c->self, c->cb_arg); | |
1913 | debug2("callback done"); | |
1914 | } | |
1915 | debug("channel %d: open confirm rwindow %d rmax %d", c->self, | |
1916 | c->remote_window, c->remote_maxpacket); | |
1917 | } | |
1918 | } | |
1919 | ||
1920 | static char * | |
1921 | reason2txt(int reason) | |
1922 | { | |
1923 | switch (reason) { | |
1924 | case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED: | |
1925 | return "administratively prohibited"; | |
1926 | case SSH2_OPEN_CONNECT_FAILED: | |
1927 | return "connect failed"; | |
1928 | case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE: | |
1929 | return "unknown channel type"; | |
1930 | case SSH2_OPEN_RESOURCE_SHORTAGE: | |
1931 | return "resource shortage"; | |
1932 | } | |
1933 | return "unknown reason"; | |
1934 | } | |
1935 | ||
1936 | void | |
1937 | channel_input_open_failure(int type, int plen, u_int32_t seq, void *ctxt) | |
1938 | { | |
1939 | int id, reason; | |
1940 | char *msg = NULL, *lang = NULL; | |
1941 | Channel *c; | |
1942 | ||
1943 | if (!compat20) | |
1944 | packet_integrity_check(plen, 4, type); | |
1945 | ||
1946 | id = packet_get_int(); | |
1947 | c = channel_lookup(id); | |
1948 | ||
1949 | if (c==NULL || c->type != SSH_CHANNEL_OPENING) | |
1950 | packet_disconnect("Received open failure for " | |
1951 | "non-opening channel %d.", id); | |
1952 | if (compat20) { | |
1953 | reason = packet_get_int(); | |
1954 | if (!(datafellows & SSH_BUG_OPENFAILURE)) { | |
1955 | msg = packet_get_string(NULL); | |
1956 | lang = packet_get_string(NULL); | |
1957 | } | |
1958 | packet_done(); | |
1959 | log("channel %d: open failed: %s%s%s", id, | |
1960 | reason2txt(reason), msg ? ": ": "", msg ? msg : ""); | |
1961 | if (msg != NULL) | |
1962 | xfree(msg); | |
1963 | if (lang != NULL) | |
1964 | xfree(lang); | |
1965 | } | |
1966 | /* Free the channel. This will also close the socket. */ | |
1967 | channel_free(c); | |
1968 | } | |
1969 | ||
1970 | void | |
1971 | channel_input_channel_request(int type, int plen, u_int32_t seq, void *ctxt) | |
1972 | { | |
1973 | int id; | |
1974 | Channel *c; | |
1975 | ||
1976 | id = packet_get_int(); | |
1977 | c = channel_lookup(id); | |
1978 | ||
1979 | if (c == NULL || | |
1980 | (c->type != SSH_CHANNEL_OPEN && c->type != SSH_CHANNEL_LARVAL)) | |
1981 | packet_disconnect("Received request for " | |
1982 | "non-open channel %d.", id); | |
1983 | if (c->cb_fn != NULL && c->cb_event == type) { | |
1984 | debug2("callback start"); | |
1985 | c->cb_fn(c->self, c->cb_arg); | |
1986 | debug2("callback done"); | |
1987 | } else { | |
1988 | char *service = packet_get_string(NULL); | |
1989 | debug("channel %d: rcvd request for %s", c->self, service); | |
1990 | debug("cb_fn %p cb_event %d", c->cb_fn , c->cb_event); | |
1991 | xfree(service); | |
1992 | } | |
1993 | } | |
1994 | ||
1995 | void | |
1996 | channel_input_window_adjust(int type, int plen, u_int32_t seq, void *ctxt) | |
1997 | { | |
1998 | Channel *c; | |
1999 | int id, adjust; | |
2000 | ||
2001 | if (!compat20) | |
2002 | return; | |
2003 | ||
2004 | /* Get the channel number and verify it. */ | |
2005 | id = packet_get_int(); | |
2006 | c = channel_lookup(id); | |
2007 | ||
2008 | if (c == NULL || c->type != SSH_CHANNEL_OPEN) { | |
2009 | log("Received window adjust for " | |
2010 | "non-open channel %d.", id); | |
2011 | return; | |
2012 | } | |
2013 | adjust = packet_get_int(); | |
2014 | packet_done(); | |
2015 | debug2("channel %d: rcvd adjust %d", id, adjust); | |
2016 | c->remote_window += adjust; | |
2017 | } | |
2018 | ||
2019 | void | |
2020 | channel_input_port_open(int type, int plen, u_int32_t seq, void *ctxt) | |
2021 | { | |
2022 | Channel *c = NULL; | |
2023 | u_short host_port; | |
2024 | char *host, *originator_string; | |
2025 | int remote_id, sock = -1; | |
2026 | ||
2027 | remote_id = packet_get_int(); | |
2028 | host = packet_get_string(NULL); | |
2029 | host_port = packet_get_int(); | |
2030 | ||
2031 | if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) { | |
2032 | originator_string = packet_get_string(NULL); | |
2033 | } else { | |
2034 | originator_string = xstrdup("unknown (remote did not supply name)"); | |
2035 | } | |
2036 | packet_done(); | |
2037 | sock = channel_connect_to(host, host_port); | |
2038 | if (sock != -1) { | |
2039 | c = channel_new("connected socket", | |
2040 | SSH_CHANNEL_CONNECTING, sock, sock, -1, 0, 0, 0, | |
2041 | originator_string, 1); | |
2042 | if (c == NULL) { | |
2043 | error("channel_input_port_open: channel_new failed"); | |
2044 | close(sock); | |
2045 | } else { | |
2046 | c->remote_id = remote_id; | |
2047 | } | |
2048 | } | |
2049 | if (c == NULL) { | |
2050 | packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); | |
2051 | packet_put_int(remote_id); | |
2052 | packet_send(); | |
2053 | } | |
2054 | xfree(host); | |
2055 | } | |
2056 | ||
2057 | ||
2058 | /* -- tcp forwarding */ | |
2059 | ||
2060 | void | |
2061 | channel_set_af(int af) | |
2062 | { | |
2063 | IPv4or6 = af; | |
2064 | } | |
2065 | ||
2066 | /* | |
2067 | * Initiate forwarding of connections to local port "port" through the secure | |
2068 | * channel to host:port from remote side. | |
2069 | */ | |
2070 | int | |
2071 | channel_request_local_forwarding(u_short listen_port, const char *host_to_connect, | |
2072 | u_short port_to_connect, int gateway_ports) | |
2073 | { | |
2074 | return channel_request_forwarding( | |
2075 | NULL, listen_port, | |
2076 | host_to_connect, port_to_connect, | |
2077 | gateway_ports, /*remote_fwd*/ 0); | |
2078 | } | |
2079 | ||
2080 | /* | |
2081 | * If 'remote_fwd' is true we have a '-R style' listener for protocol 2 | |
2082 | * (SSH_CHANNEL_RPORT_LISTENER). | |
2083 | */ | |
2084 | int | |
2085 | channel_request_forwarding( | |
2086 | const char *listen_address, u_short listen_port, | |
2087 | const char *host_to_connect, u_short port_to_connect, | |
2088 | int gateway_ports, int remote_fwd) | |
2089 | { | |
2090 | Channel *c; | |
2091 | int success, sock, on = 1, type; | |
2092 | struct addrinfo hints, *ai, *aitop; | |
2093 | char ntop[NI_MAXHOST], strport[NI_MAXSERV]; | |
2094 | const char *host; | |
2095 | struct linger linger; | |
2096 | ||
2097 | success = 0; | |
2098 | ||
2099 | if (remote_fwd) { | |
2100 | host = listen_address; | |
2101 | type = SSH_CHANNEL_RPORT_LISTENER; | |
2102 | } else { | |
2103 | host = host_to_connect; | |
2104 | type = SSH_CHANNEL_PORT_LISTENER; | |
2105 | } | |
2106 | ||
2107 | if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) { | |
2108 | error("Forward host name too long."); | |
2109 | return success; | |
2110 | } | |
2111 | ||
2112 | /* XXX listen_address is currently ignored */ | |
2113 | /* | |
2114 | * getaddrinfo returns a loopback address if the hostname is | |
2115 | * set to NULL and hints.ai_flags is not AI_PASSIVE | |
2116 | */ | |
2117 | memset(&hints, 0, sizeof(hints)); | |
2118 | hints.ai_family = IPv4or6; | |
2119 | hints.ai_flags = gateway_ports ? AI_PASSIVE : 0; | |
2120 | hints.ai_socktype = SOCK_STREAM; | |
2121 | snprintf(strport, sizeof strport, "%d", listen_port); | |
2122 | if (getaddrinfo(NULL, strport, &hints, &aitop) != 0) | |
2123 | packet_disconnect("getaddrinfo: fatal error"); | |
2124 | ||
2125 | for (ai = aitop; ai; ai = ai->ai_next) { | |
2126 | if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) | |
2127 | continue; | |
2128 | if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), | |
2129 | strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) { | |
2130 | error("channel_request_forwarding: getnameinfo failed"); | |
2131 | continue; | |
2132 | } | |
2133 | /* Create a port to listen for the host. */ | |
2134 | sock = socket(ai->ai_family, SOCK_STREAM, 0); | |
2135 | if (sock < 0) { | |
2136 | /* this is no error since kernel may not support ipv6 */ | |
2137 | verbose("socket: %.100s", strerror(errno)); | |
2138 | continue; | |
2139 | } | |
2140 | /* | |
2141 | * Set socket options. We would like the socket to disappear | |
2142 | * as soon as it has been closed for whatever reason. | |
2143 | */ | |
2144 | setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on)); | |
2145 | linger.l_onoff = 1; | |
2146 | linger.l_linger = 5; | |
2147 | setsockopt(sock, SOL_SOCKET, SO_LINGER, (void *)&linger, sizeof(linger)); | |
2148 | debug("Local forwarding listening on %s port %s.", ntop, strport); | |
2149 | ||
2150 | /* Bind the socket to the address. */ | |
2151 | if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) { | |
2152 | /* address can be in use ipv6 address is already bound */ | |
2153 | if (!ai->ai_next) | |
2154 | error("bind: %.100s", strerror(errno)); | |
2155 | else | |
2156 | verbose("bind: %.100s", strerror(errno)); | |
2157 | ||
2158 | close(sock); | |
2159 | continue; | |
2160 | } | |
2161 | /* Start listening for connections on the socket. */ | |
2162 | if (listen(sock, 5) < 0) { | |
2163 | error("listen: %.100s", strerror(errno)); | |
2164 | close(sock); | |
2165 | continue; | |
2166 | } | |
2167 | /* Allocate a channel number for the socket. */ | |
2168 | c = channel_new("port listener", type, sock, sock, -1, | |
2169 | CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, | |
2170 | 0, xstrdup("port listener"), 1); | |
2171 | if (c == NULL) { | |
2172 | error("channel_request_forwarding: channel_new failed"); | |
2173 | close(sock); | |
2174 | continue; | |
2175 | } | |
2176 | strlcpy(c->path, host, sizeof(c->path)); | |
2177 | c->host_port = port_to_connect; | |
2178 | c->listening_port = listen_port; | |
2179 | success = 1; | |
2180 | } | |
2181 | if (success == 0) | |
2182 | error("channel_request_forwarding: cannot listen to port: %d", | |
2183 | listen_port); | |
2184 | freeaddrinfo(aitop); | |
2185 | return success; | |
2186 | } | |
2187 | ||
2188 | /* | |
2189 | * Initiate forwarding of connections to port "port" on remote host through | |
2190 | * the secure channel to host:port from local side. | |
2191 | */ | |
2192 | ||
2193 | void | |
2194 | channel_request_remote_forwarding(u_short listen_port, | |
2195 | const char *host_to_connect, u_short port_to_connect) | |
2196 | { | |
2197 | int payload_len, type, success = 0; | |
2198 | ||
2199 | /* Record locally that connection to this host/port is permitted. */ | |
2200 | if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION) | |
2201 | fatal("channel_request_remote_forwarding: too many forwards"); | |
2202 | ||
2203 | /* Send the forward request to the remote side. */ | |
2204 | if (compat20) { | |
2205 | const char *address_to_bind = "0.0.0.0"; | |
2206 | packet_start(SSH2_MSG_GLOBAL_REQUEST); | |
2207 | packet_put_cstring("tcpip-forward"); | |
2208 | packet_put_char(0); /* boolean: want reply */ | |
2209 | packet_put_cstring(address_to_bind); | |
2210 | packet_put_int(listen_port); | |
2211 | packet_send(); | |
2212 | packet_write_wait(); | |
2213 | /* Assume that server accepts the request */ | |
2214 | success = 1; | |
2215 | } else { | |
2216 | packet_start(SSH_CMSG_PORT_FORWARD_REQUEST); | |
2217 | packet_put_int(listen_port); | |
2218 | packet_put_cstring(host_to_connect); | |
2219 | packet_put_int(port_to_connect); | |
2220 | packet_send(); | |
2221 | packet_write_wait(); | |
2222 | ||
2223 | /* Wait for response from the remote side. */ | |
2224 | type = packet_read(&payload_len); | |
2225 | switch (type) { | |
2226 | case SSH_SMSG_SUCCESS: | |
2227 | success = 1; | |
2228 | break; | |
2229 | case SSH_SMSG_FAILURE: | |
2230 | log("Warning: Server denied remote port forwarding."); | |
2231 | break; | |
2232 | default: | |
2233 | /* Unknown packet */ | |
2234 | packet_disconnect("Protocol error for port forward request:" | |
2235 | "received packet type %d.", type); | |
2236 | } | |
2237 | } | |
2238 | if (success) { | |
2239 | permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect); | |
2240 | permitted_opens[num_permitted_opens].port_to_connect = port_to_connect; | |
2241 | permitted_opens[num_permitted_opens].listen_port = listen_port; | |
2242 | num_permitted_opens++; | |
2243 | } | |
2244 | } | |
2245 | ||
2246 | /* | |
2247 | * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates | |
2248 | * listening for the port, and sends back a success reply (or disconnect | |
2249 | * message if there was an error). This never returns if there was an error. | |
2250 | */ | |
2251 | ||
2252 | void | |
2253 | channel_input_port_forward_request(int is_root, int gateway_ports) | |
2254 | { | |
2255 | u_short port, host_port; | |
2256 | char *hostname; | |
2257 | ||
2258 | /* Get arguments from the packet. */ | |
2259 | port = packet_get_int(); | |
2260 | hostname = packet_get_string(NULL); | |
2261 | host_port = packet_get_int(); | |
2262 | ||
2263 | #ifndef HAVE_CYGWIN | |
2264 | /* | |
2265 | * Check that an unprivileged user is not trying to forward a | |
2266 | * privileged port. | |
2267 | */ | |
2268 | if (port < IPPORT_RESERVED && !is_root) | |
2269 | packet_disconnect("Requested forwarding of port %d but user is not root.", | |
2270 | port); | |
2271 | #endif | |
2272 | /* Initiate forwarding */ | |
2273 | channel_request_local_forwarding(port, hostname, host_port, gateway_ports); | |
2274 | ||
2275 | /* Free the argument string. */ | |
2276 | xfree(hostname); | |
2277 | } | |
2278 | ||
2279 | /* | |
2280 | * Permits opening to any host/port if permitted_opens[] is empty. This is | |
2281 | * usually called by the server, because the user could connect to any port | |
2282 | * anyway, and the server has no way to know but to trust the client anyway. | |
2283 | */ | |
2284 | void | |
2285 | channel_permit_all_opens(void) | |
2286 | { | |
2287 | if (num_permitted_opens == 0) | |
2288 | all_opens_permitted = 1; | |
2289 | } | |
2290 | ||
2291 | void | |
2292 | channel_add_permitted_opens(char *host, int port) | |
2293 | { | |
2294 | if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION) | |
2295 | fatal("channel_request_remote_forwarding: too many forwards"); | |
2296 | debug("allow port forwarding to host %s port %d", host, port); | |
2297 | ||
2298 | permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host); | |
2299 | permitted_opens[num_permitted_opens].port_to_connect = port; | |
2300 | num_permitted_opens++; | |
2301 | ||
2302 | all_opens_permitted = 0; | |
2303 | } | |
2304 | ||
2305 | void | |
2306 | channel_clear_permitted_opens(void) | |
2307 | { | |
2308 | int i; | |
2309 | ||
2310 | for (i = 0; i < num_permitted_opens; i++) | |
2311 | xfree(permitted_opens[i].host_to_connect); | |
2312 | num_permitted_opens = 0; | |
2313 | ||
2314 | } | |
2315 | ||
2316 | ||
2317 | /* return socket to remote host, port */ | |
2318 | static int | |
2319 | connect_to(const char *host, u_short port) | |
2320 | { | |
2321 | struct addrinfo hints, *ai, *aitop; | |
2322 | char ntop[NI_MAXHOST], strport[NI_MAXSERV]; | |
2323 | int gaierr; | |
2324 | int sock = -1; | |
2325 | ||
2326 | memset(&hints, 0, sizeof(hints)); | |
2327 | hints.ai_family = IPv4or6; | |
2328 | hints.ai_socktype = SOCK_STREAM; | |
2329 | snprintf(strport, sizeof strport, "%d", port); | |
2330 | if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) { | |
2331 | error("connect_to %.100s: unknown host (%s)", host, | |
2332 | gai_strerror(gaierr)); | |
2333 | return -1; | |
2334 | } | |
2335 | for (ai = aitop; ai; ai = ai->ai_next) { | |
2336 | if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) | |
2337 | continue; | |
2338 | if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), | |
2339 | strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) { | |
2340 | error("connect_to: getnameinfo failed"); | |
2341 | continue; | |
2342 | } | |
2343 | sock = socket(ai->ai_family, SOCK_STREAM, 0); | |
2344 | if (sock < 0) { | |
2345 | error("socket: %.100s", strerror(errno)); | |
2346 | continue; | |
2347 | } | |
2348 | if (fcntl(sock, F_SETFL, O_NONBLOCK) < 0) | |
2349 | fatal("connect_to: F_SETFL: %s", strerror(errno)); | |
2350 | if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 && | |
2351 | errno != EINPROGRESS) { | |
2352 | error("connect_to %.100s port %s: %.100s", ntop, strport, | |
2353 | strerror(errno)); | |
2354 | close(sock); | |
2355 | continue; /* fail -- try next */ | |
2356 | } | |
2357 | break; /* success */ | |
2358 | ||
2359 | } | |
2360 | freeaddrinfo(aitop); | |
2361 | if (!ai) { | |
2362 | error("connect_to %.100s port %d: failed.", host, port); | |
2363 | return -1; | |
2364 | } | |
2365 | /* success */ | |
2366 | return sock; | |
2367 | } | |
2368 | ||
2369 | int | |
2370 | channel_connect_by_listen_address(u_short listen_port) | |
2371 | { | |
2372 | int i; | |
2373 | ||
2374 | for (i = 0; i < num_permitted_opens; i++) | |
2375 | if (permitted_opens[i].listen_port == listen_port) | |
2376 | return connect_to( | |
2377 | permitted_opens[i].host_to_connect, | |
2378 | permitted_opens[i].port_to_connect); | |
2379 | error("WARNING: Server requests forwarding for unknown listen_port %d", | |
2380 | listen_port); | |
2381 | return -1; | |
2382 | } | |
2383 | ||
2384 | /* Check if connecting to that port is permitted and connect. */ | |
2385 | int | |
2386 | channel_connect_to(const char *host, u_short port) | |
2387 | { | |
2388 | int i, permit; | |
2389 | ||
2390 | permit = all_opens_permitted; | |
2391 | if (!permit) { | |
2392 | for (i = 0; i < num_permitted_opens; i++) | |
2393 | if (permitted_opens[i].port_to_connect == port && | |
2394 | strcmp(permitted_opens[i].host_to_connect, host) == 0) | |
2395 | permit = 1; | |
2396 | ||
2397 | } | |
2398 | if (!permit) { | |
2399 | log("Received request to connect to host %.100s port %d, " | |
2400 | "but the request was denied.", host, port); | |
2401 | return -1; | |
2402 | } | |
2403 | return connect_to(host, port); | |
2404 | } | |
2405 | ||
2406 | /* -- X11 forwarding */ | |
2407 | ||
2408 | /* | |
2409 | * Creates an internet domain socket for listening for X11 connections. | |
2410 | * Returns a suitable display number for the DISPLAY variable, or -1 if | |
2411 | * an error occurs. | |
2412 | */ | |
2413 | int | |
2414 | x11_create_display_inet(int x11_display_offset, int gateway_ports, | |
2415 | int single_connection) | |
2416 | { | |
2417 | Channel *nc = NULL; | |
2418 | int display_number, sock; | |
2419 | u_short port; | |
2420 | struct addrinfo hints, *ai, *aitop; | |
2421 | char strport[NI_MAXSERV]; | |
2422 | int gaierr, n, num_socks = 0, socks[NUM_SOCKS]; | |
2423 | ||
2424 | for (display_number = x11_display_offset; | |
2425 | display_number < MAX_DISPLAYS; | |
2426 | display_number++) { | |
2427 | port = 6000 + display_number; | |
2428 | memset(&hints, 0, sizeof(hints)); | |
2429 | hints.ai_family = IPv4or6; | |
2430 | hints.ai_flags = gateway_ports ? AI_PASSIVE : 0; | |
2431 | hints.ai_socktype = SOCK_STREAM; | |
2432 | snprintf(strport, sizeof strport, "%d", port); | |
2433 | if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) { | |
2434 | error("getaddrinfo: %.100s", gai_strerror(gaierr)); | |
2435 | return -1; | |
2436 | } | |
2437 | for (ai = aitop; ai; ai = ai->ai_next) { | |
2438 | if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) | |
2439 | continue; | |
2440 | sock = socket(ai->ai_family, SOCK_STREAM, 0); | |
2441 | if (sock < 0) { | |
2442 | if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) { | |
2443 | error("socket: %.100s", strerror(errno)); | |
2444 | return -1; | |
2445 | } else { | |
2446 | debug("x11_create_display_inet: Socket family %d not supported", | |
2447 | ai->ai_family); | |
2448 | continue; | |
2449 | } | |
2450 | } | |
2451 | if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) { | |
2452 | debug("bind port %d: %.100s", port, strerror(errno)); | |
2453 | close(sock); | |
2454 | ||
2455 | if (ai->ai_next) | |
2456 | continue; | |
2457 | ||
2458 | for (n = 0; n < num_socks; n++) { | |
2459 | close(socks[n]); | |
2460 | } | |
2461 | num_socks = 0; | |
2462 | break; | |
2463 | } | |
2464 | socks[num_socks++] = sock; | |
2465 | #ifndef DONT_TRY_OTHER_AF | |
2466 | if (num_socks == NUM_SOCKS) | |
2467 | break; | |
2468 | #else | |
2469 | break; | |
2470 | #endif | |
2471 | } | |
2472 | freeaddrinfo(aitop); | |
2473 | if (num_socks > 0) | |
2474 | break; | |
2475 | } | |
2476 | if (display_number >= MAX_DISPLAYS) { | |
2477 | error("Failed to allocate internet-domain X11 display socket."); | |
2478 | return -1; | |
2479 | } | |
2480 | /* Start listening for connections on the socket. */ | |
2481 | for (n = 0; n < num_socks; n++) { | |
2482 | sock = socks[n]; | |
2483 | if (listen(sock, 5) < 0) { | |
2484 | error("listen: %.100s", strerror(errno)); | |
2485 | close(sock); | |
2486 | return -1; | |
2487 | } | |
2488 | } | |
2489 | ||
2490 | /* Allocate a channel for each socket. */ | |
2491 | for (n = 0; n < num_socks; n++) { | |
2492 | sock = socks[n]; | |
2493 | nc = channel_new("x11 listener", | |
2494 | SSH_CHANNEL_X11_LISTENER, sock, sock, -1, | |
2495 | CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, | |
2496 | 0, xstrdup("X11 inet listener"), 1); | |
2497 | if (nc != NULL) | |
2498 | nc->single_connection = single_connection; | |
2499 | } | |
2500 | ||
2501 | /* Return the display number for the DISPLAY environment variable. */ | |
2502 | return display_number; | |
2503 | } | |
2504 | ||
2505 | static int | |
2506 | connect_local_xsocket(u_int dnr) | |
2507 | { | |
2508 | int sock; | |
2509 | struct sockaddr_un addr; | |
2510 | ||
2511 | sock = socket(AF_UNIX, SOCK_STREAM, 0); | |
2512 | if (sock < 0) | |
2513 | error("socket: %.100s", strerror(errno)); | |
2514 | memset(&addr, 0, sizeof(addr)); | |
2515 | addr.sun_family = AF_UNIX; | |
2516 | snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr); | |
2517 | if (connect(sock, (struct sockaddr *) & addr, sizeof(addr)) == 0) | |
2518 | return sock; | |
2519 | close(sock); | |
2520 | error("connect %.100s: %.100s", addr.sun_path, strerror(errno)); | |
2521 | return -1; | |
2522 | } | |
2523 | ||
2524 | int | |
2525 | x11_connect_display(void) | |
2526 | { | |
2527 | int display_number, sock = 0, on = 1; | |
2528 | const char *display; | |
2529 | char buf[1024], *cp; | |
2530 | struct addrinfo hints, *ai, *aitop; | |
2531 | char strport[NI_MAXSERV]; | |
2532 | int gaierr; | |
2533 | ||
2534 | /* Try to open a socket for the local X server. */ | |
2535 | display = getenv("DISPLAY"); | |
2536 | if (!display) { | |
2537 | error("DISPLAY not set."); | |
2538 | return -1; | |
2539 | } | |
2540 | /* | |
2541 | * Now we decode the value of the DISPLAY variable and make a | |
2542 | * connection to the real X server. | |
2543 | */ | |
2544 | ||
2545 | /* | |
2546 | * Check if it is a unix domain socket. Unix domain displays are in | |
2547 | * one of the following formats: unix:d[.s], :d[.s], ::d[.s] | |
2548 | */ | |
2549 | if (strncmp(display, "unix:", 5) == 0 || | |
2550 | display[0] == ':') { | |
2551 | /* Connect to the unix domain socket. */ | |
2552 | if (sscanf(strrchr(display, ':') + 1, "%d", &display_number) != 1) { | |
2553 | error("Could not parse display number from DISPLAY: %.100s", | |
2554 | display); | |
2555 | return -1; | |
2556 | } | |
2557 | /* Create a socket. */ | |
2558 | sock = connect_local_xsocket(display_number); | |
2559 | if (sock < 0) | |
2560 | return -1; | |
2561 | ||
2562 | /* OK, we now have a connection to the display. */ | |
2563 | return sock; | |
2564 | } | |
2565 | /* | |
2566 | * Connect to an inet socket. The DISPLAY value is supposedly | |
2567 | * hostname:d[.s], where hostname may also be numeric IP address. | |
2568 | */ | |
2569 | strlcpy(buf, display, sizeof(buf)); | |
2570 | cp = strchr(buf, ':'); | |
2571 | if (!cp) { | |
2572 | error("Could not find ':' in DISPLAY: %.100s", display); | |
2573 | return -1; | |
2574 | } | |
2575 | *cp = 0; | |
2576 | /* buf now contains the host name. But first we parse the display number. */ | |
2577 | if (sscanf(cp + 1, "%d", &display_number) != 1) { | |
2578 | error("Could not parse display number from DISPLAY: %.100s", | |
2579 | display); | |
2580 | return -1; | |
2581 | } | |
2582 | ||
2583 | /* Look up the host address */ | |
2584 | memset(&hints, 0, sizeof(hints)); | |
2585 | hints.ai_family = IPv4or6; | |
2586 | hints.ai_socktype = SOCK_STREAM; | |
2587 | snprintf(strport, sizeof strport, "%d", 6000 + display_number); | |
2588 | if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) { | |
2589 | error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr)); | |
2590 | return -1; | |
2591 | } | |
2592 | for (ai = aitop; ai; ai = ai->ai_next) { | |
2593 | /* Create a socket. */ | |
2594 | sock = socket(ai->ai_family, SOCK_STREAM, 0); | |
2595 | if (sock < 0) { | |
2596 | debug("socket: %.100s", strerror(errno)); | |
2597 | continue; | |
2598 | } | |
2599 | /* Connect it to the display. */ | |
2600 | if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) { | |
2601 | debug("connect %.100s port %d: %.100s", buf, | |
2602 | 6000 + display_number, strerror(errno)); | |
2603 | close(sock); | |
2604 | continue; | |
2605 | } | |
2606 | /* Success */ | |
2607 | break; | |
2608 | } | |
2609 | freeaddrinfo(aitop); | |
2610 | if (!ai) { | |
2611 | error("connect %.100s port %d: %.100s", buf, 6000 + display_number, | |
2612 | strerror(errno)); | |
2613 | return -1; | |
2614 | } | |
2615 | if (setsockopt(sock, IPPROTO_TCP, TCP_NODELAY, &on, sizeof on) == -1) | |
2616 | error("setsockopt TCP_NODELAY: %.100s", strerror(errno)); | |
2617 | return sock; | |
2618 | } | |
2619 | ||
2620 | /* | |
2621 | * This is called when SSH_SMSG_X11_OPEN is received. The packet contains | |
2622 | * the remote channel number. We should do whatever we want, and respond | |
2623 | * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE. | |
2624 | */ | |
2625 | ||
2626 | void | |
2627 | x11_input_open(int type, int plen, u_int32_t seq, void *ctxt) | |
2628 | { | |
2629 | Channel *c = NULL; | |
2630 | int remote_id, sock = 0; | |
2631 | char *remote_host; | |
2632 | ||
2633 | debug("Received X11 open request."); | |
2634 | ||
2635 | remote_id = packet_get_int(); | |
2636 | ||
2637 | if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) { | |
2638 | remote_host = packet_get_string(NULL); | |
2639 | } else { | |
2640 | remote_host = xstrdup("unknown (remote did not supply name)"); | |
2641 | } | |
2642 | packet_done(); | |
2643 | ||
2644 | /* Obtain a connection to the real X display. */ | |
2645 | sock = x11_connect_display(); | |
2646 | if (sock != -1) { | |
2647 | /* Allocate a channel for this connection. */ | |
2648 | c = channel_new("connected x11 socket", | |
2649 | SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0, | |
2650 | remote_host, 1); | |
2651 | if (c == NULL) { | |
2652 | error("x11_input_open: channel_new failed"); | |
2653 | close(sock); | |
2654 | } else { | |
2655 | c->remote_id = remote_id; | |
2656 | c->force_drain = 1; | |
2657 | } | |
2658 | } | |
2659 | if (c == NULL) { | |
2660 | /* Send refusal to the remote host. */ | |
2661 | packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); | |
2662 | packet_put_int(remote_id); | |
2663 | } else { | |
2664 | /* Send a confirmation to the remote host. */ | |
2665 | packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION); | |
2666 | packet_put_int(remote_id); | |
2667 | packet_put_int(c->self); | |
2668 | } | |
2669 | packet_send(); | |
2670 | } | |
2671 | ||
2672 | /* dummy protocol handler that denies SSH-1 requests (agent/x11) */ | |
2673 | void | |
2674 | deny_input_open(int type, int plen, u_int32_t seq, void *ctxt) | |
2675 | { | |
2676 | int rchan = packet_get_int(); | |
2677 | switch (type) { | |
2678 | case SSH_SMSG_AGENT_OPEN: | |
2679 | error("Warning: ssh server tried agent forwarding."); | |
2680 | break; | |
2681 | case SSH_SMSG_X11_OPEN: | |
2682 | error("Warning: ssh server tried X11 forwarding."); | |
2683 | break; | |
2684 | default: | |
2685 | error("deny_input_open: type %d plen %d", type, plen); | |
2686 | break; | |
2687 | } | |
2688 | error("Warning: this is probably a break in attempt by a malicious server."); | |
2689 | packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); | |
2690 | packet_put_int(rchan); | |
2691 | packet_send(); | |
2692 | } | |
2693 | ||
2694 | /* | |
2695 | * Requests forwarding of X11 connections, generates fake authentication | |
2696 | * data, and enables authentication spoofing. | |
2697 | * This should be called in the client only. | |
2698 | */ | |
2699 | void | |
2700 | x11_request_forwarding_with_spoofing(int client_session_id, | |
2701 | const char *proto, const char *data) | |
2702 | { | |
2703 | u_int data_len = (u_int) strlen(data) / 2; | |
2704 | u_int i, value, len; | |
2705 | char *new_data; | |
2706 | int screen_number; | |
2707 | const char *cp; | |
2708 | u_int32_t rand = 0; | |
2709 | ||
2710 | cp = getenv("DISPLAY"); | |
2711 | if (cp) | |
2712 | cp = strchr(cp, ':'); | |
2713 | if (cp) | |
2714 | cp = strchr(cp, '.'); | |
2715 | if (cp) | |
2716 | screen_number = atoi(cp + 1); | |
2717 | else | |
2718 | screen_number = 0; | |
2719 | ||
2720 | /* Save protocol name. */ | |
2721 | x11_saved_proto = xstrdup(proto); | |
2722 | ||
2723 | /* | |
2724 | * Extract real authentication data and generate fake data of the | |
2725 | * same length. | |
2726 | */ | |
2727 | x11_saved_data = xmalloc(data_len); | |
2728 | x11_fake_data = xmalloc(data_len); | |
2729 | for (i = 0; i < data_len; i++) { | |
2730 | if (sscanf(data + 2 * i, "%2x", &value) != 1) | |
2731 | fatal("x11_request_forwarding: bad authentication data: %.100s", data); | |
2732 | if (i % 4 == 0) | |
2733 | rand = arc4random(); | |
2734 | x11_saved_data[i] = value; | |
2735 | x11_fake_data[i] = rand & 0xff; | |
2736 | rand >>= 8; | |
2737 | } | |
2738 | x11_saved_data_len = data_len; | |
2739 | x11_fake_data_len = data_len; | |
2740 | ||
2741 | /* Convert the fake data into hex. */ | |
2742 | len = 2 * data_len + 1; | |
2743 | new_data = xmalloc(len); | |
2744 | for (i = 0; i < data_len; i++) | |
2745 | snprintf(new_data + 2 * i, len - 2 * i, | |
2746 | "%02x", (u_char) x11_fake_data[i]); | |
2747 | ||
2748 | /* Send the request packet. */ | |
2749 | if (compat20) { | |
2750 | channel_request_start(client_session_id, "x11-req", 0); | |
2751 | packet_put_char(0); /* XXX bool single connection */ | |
2752 | } else { | |
2753 | packet_start(SSH_CMSG_X11_REQUEST_FORWARDING); | |
2754 | } | |
2755 | packet_put_cstring(proto); | |
2756 | packet_put_cstring(new_data); | |
2757 | packet_put_int(screen_number); | |
2758 | packet_send(); | |
2759 | packet_write_wait(); | |
2760 | xfree(new_data); | |
2761 | } | |
2762 | ||
2763 | ||
2764 | /* -- agent forwarding */ | |
2765 | ||
2766 | /* Sends a message to the server to request authentication fd forwarding. */ | |
2767 | ||
2768 | void | |
2769 | auth_request_forwarding(void) | |
2770 | { | |
2771 | packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING); | |
2772 | packet_send(); | |
2773 | packet_write_wait(); | |
2774 | } | |
2775 | ||
2776 | /* | |
2777 | * Returns the name of the forwarded authentication socket. Returns NULL if | |
2778 | * there is no forwarded authentication socket. The returned value points to | |
2779 | * a static buffer. | |
2780 | */ | |
2781 | ||
2782 | char * | |
2783 | auth_get_socket_name(void) | |
2784 | { | |
2785 | return auth_sock_name; | |
2786 | } | |
2787 | ||
2788 | /* removes the agent forwarding socket */ | |
2789 | ||
2790 | void | |
2791 | auth_sock_cleanup_proc(void *_pw) | |
2792 | { | |
2793 | struct passwd *pw = _pw; | |
2794 | ||
2795 | if (auth_sock_name) { | |
2796 | temporarily_use_uid(pw); | |
2797 | unlink(auth_sock_name); | |
2798 | rmdir(auth_sock_dir); | |
2799 | auth_sock_name = NULL; | |
2800 | restore_uid(); | |
2801 | } | |
2802 | } | |
2803 | ||
2804 | /* | |
2805 | * This is called to process SSH_CMSG_AGENT_REQUEST_FORWARDING on the server. | |
2806 | * This starts forwarding authentication requests. | |
2807 | */ | |
2808 | ||
2809 | int | |
2810 | auth_input_request_forwarding(struct passwd * pw) | |
2811 | { | |
2812 | Channel *nc; | |
2813 | int sock; | |
2814 | struct sockaddr_un sunaddr; | |
2815 | ||
2816 | if (auth_get_socket_name() != NULL) { | |
2817 | error("authentication forwarding requested twice."); | |
2818 | return 0; | |
2819 | } | |
2820 | ||
2821 | /* Temporarily drop privileged uid for mkdir/bind. */ | |
2822 | temporarily_use_uid(pw); | |
2823 | ||
2824 | /* Allocate a buffer for the socket name, and format the name. */ | |
2825 | auth_sock_name = xmalloc(MAXPATHLEN); | |
2826 | auth_sock_dir = xmalloc(MAXPATHLEN); | |
2827 | strlcpy(auth_sock_dir, "/tmp/ssh-XXXXXXXX", MAXPATHLEN); | |
2828 | ||
2829 | /* Create private directory for socket */ | |
2830 | if (mkdtemp(auth_sock_dir) == NULL) { | |
2831 | packet_send_debug("Agent forwarding disabled: " | |
2832 | "mkdtemp() failed: %.100s", strerror(errno)); | |
2833 | restore_uid(); | |
2834 | xfree(auth_sock_name); | |
2835 | xfree(auth_sock_dir); | |
2836 | auth_sock_name = NULL; | |
2837 | auth_sock_dir = NULL; | |
2838 | return 0; | |
2839 | } | |
2840 | snprintf(auth_sock_name, MAXPATHLEN, "%s/agent.%d", | |
2841 | auth_sock_dir, (int) getpid()); | |
2842 | ||
2843 | /* delete agent socket on fatal() */ | |
2844 | fatal_add_cleanup(auth_sock_cleanup_proc, pw); | |
2845 | ||
2846 | /* Create the socket. */ | |
2847 | sock = socket(AF_UNIX, SOCK_STREAM, 0); | |
2848 | if (sock < 0) | |
2849 | packet_disconnect("socket: %.100s", strerror(errno)); | |
2850 | ||
2851 | /* Bind it to the name. */ | |
2852 | memset(&sunaddr, 0, sizeof(sunaddr)); | |
2853 | sunaddr.sun_family = AF_UNIX; | |
2854 | strlcpy(sunaddr.sun_path, auth_sock_name, sizeof(sunaddr.sun_path)); | |
2855 | ||
2856 | if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0) | |
2857 | packet_disconnect("bind: %.100s", strerror(errno)); | |
2858 | ||
2859 | /* Restore the privileged uid. */ | |
2860 | restore_uid(); | |
2861 | ||
2862 | /* Start listening on the socket. */ | |
2863 | if (listen(sock, 5) < 0) | |
2864 | packet_disconnect("listen: %.100s", strerror(errno)); | |
2865 | ||
2866 | /* Allocate a channel for the authentication agent socket. */ | |
2867 | nc = channel_new("auth socket", | |
2868 | SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1, | |
2869 | CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, | |
2870 | 0, xstrdup("auth socket"), 1); | |
2871 | if (nc == NULL) { | |
2872 | error("auth_input_request_forwarding: channel_new failed"); | |
2873 | auth_sock_cleanup_proc(pw); | |
2874 | fatal_remove_cleanup(auth_sock_cleanup_proc, pw); | |
2875 | close(sock); | |
2876 | return 0; | |
2877 | } | |
2878 | strlcpy(nc->path, auth_sock_name, sizeof(nc->path)); | |
2879 | return 1; | |
2880 | } | |
2881 | ||
2882 | /* This is called to process an SSH_SMSG_AGENT_OPEN message. */ | |
2883 | ||
2884 | void | |
2885 | auth_input_open_request(int type, int plen, u_int32_t seq, void *ctxt) | |
2886 | { | |
2887 | Channel *c = NULL; | |
2888 | int remote_id, sock; | |
2889 | char *name; | |
2890 | ||
2891 | packet_integrity_check(plen, 4, type); | |
2892 | ||
2893 | /* Read the remote channel number from the message. */ | |
2894 | remote_id = packet_get_int(); | |
2895 | ||
2896 | /* | |
2897 | * Get a connection to the local authentication agent (this may again | |
2898 | * get forwarded). | |
2899 | */ | |
2900 | sock = ssh_get_authentication_socket(); | |
2901 | ||
2902 | /* | |
2903 | * If we could not connect the agent, send an error message back to | |
2904 | * the server. This should never happen unless the agent dies, | |
2905 | * because authentication forwarding is only enabled if we have an | |
2906 | * agent. | |
2907 | */ | |
2908 | if (sock >= 0) { | |
2909 | name = xstrdup("authentication agent connection"); | |
2910 | c = channel_new("", SSH_CHANNEL_OPEN, sock, sock, | |
2911 | -1, 0, 0, 0, name, 1); | |
2912 | if (c == NULL) { | |
2913 | error("auth_input_open_request: channel_new failed"); | |
2914 | xfree(name); | |
2915 | close(sock); | |
2916 | } else { | |
2917 | c->remote_id = remote_id; | |
2918 | c->force_drain = 1; | |
2919 | } | |
2920 | } | |
2921 | if (c == NULL) { | |
2922 | packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); | |
2923 | packet_put_int(remote_id); | |
2924 | } else { | |
2925 | /* Send a confirmation to the remote host. */ | |
2926 | debug("Forwarding authentication connection."); | |
2927 | packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION); | |
2928 | packet_put_int(remote_id); | |
2929 | packet_put_int(c->self); | |
2930 | } | |
2931 | packet_send(); | |
2932 | } |