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3c0ef626 | 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 1.140 2001/10/10 22:18:47 markus 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 | ||
58 | ||
59 | /* -- channel core */ | |
60 | ||
61 | /* | |
62 | * Pointer to an array containing all allocated channels. The array is | |
63 | * dynamically extended as needed. | |
64 | */ | |
65 | static Channel **channels = NULL; | |
66 | ||
67 | /* | |
68 | * Size of the channel array. All slots of the array must always be | |
69 | * initialized (at least the type field); unused slots set to NULL | |
70 | */ | |
71 | static int channels_alloc = 0; | |
72 | ||
73 | /* | |
74 | * Maximum file descriptor value used in any of the channels. This is | |
75 | * updated in channel_new. | |
76 | */ | |
77 | static int channel_max_fd = 0; | |
78 | ||
79 | ||
80 | /* -- tcp forwarding */ | |
81 | ||
82 | /* | |
83 | * Data structure for storing which hosts are permitted for forward requests. | |
84 | * The local sides of any remote forwards are stored in this array to prevent | |
85 | * a corrupt remote server from accessing arbitrary TCP/IP ports on our local | |
86 | * network (which might be behind a firewall). | |
87 | */ | |
88 | typedef struct { | |
89 | char *host_to_connect; /* Connect to 'host'. */ | |
90 | u_short port_to_connect; /* Connect to 'port'. */ | |
91 | u_short listen_port; /* Remote side should listen port number. */ | |
92 | } ForwardPermission; | |
93 | ||
94 | /* List of all permitted host/port pairs to connect. */ | |
95 | static ForwardPermission permitted_opens[SSH_MAX_FORWARDS_PER_DIRECTION]; | |
96 | ||
97 | /* Number of permitted host/port pairs in the array. */ | |
98 | static int num_permitted_opens = 0; | |
99 | /* | |
100 | * If this is true, all opens are permitted. This is the case on the server | |
101 | * on which we have to trust the client anyway, and the user could do | |
102 | * anything after logging in anyway. | |
103 | */ | |
104 | static int all_opens_permitted = 0; | |
105 | ||
106 | ||
107 | /* -- X11 forwarding */ | |
108 | ||
109 | /* Maximum number of fake X11 displays to try. */ | |
110 | #define MAX_DISPLAYS 1000 | |
111 | ||
112 | /* Saved X11 authentication protocol name. */ | |
113 | static char *x11_saved_proto = NULL; | |
114 | ||
115 | /* Saved X11 authentication data. This is the real data. */ | |
116 | static char *x11_saved_data = NULL; | |
117 | static u_int x11_saved_data_len = 0; | |
118 | ||
119 | /* | |
120 | * Fake X11 authentication data. This is what the server will be sending us; | |
121 | * we should replace any occurrences of this by the real data. | |
122 | */ | |
123 | static char *x11_fake_data = NULL; | |
124 | static u_int x11_fake_data_len; | |
125 | ||
126 | ||
127 | /* -- agent forwarding */ | |
128 | ||
129 | #define NUM_SOCKS 10 | |
130 | ||
131 | /* Name and directory of socket for authentication agent forwarding. */ | |
132 | static char *auth_sock_name = NULL; | |
133 | static char *auth_sock_dir = NULL; | |
134 | ||
135 | /* AF_UNSPEC or AF_INET or AF_INET6 */ | |
136 | static int IPv4or6 = AF_UNSPEC; | |
137 | ||
138 | /* helper */ | |
139 | static void port_open_helper(Channel *c, char *rtype); | |
140 | ||
141 | /* -- channel core */ | |
142 | ||
143 | Channel * | |
144 | channel_lookup(int id) | |
145 | { | |
146 | Channel *c; | |
147 | ||
148 | if (id < 0 || id > channels_alloc) { | |
149 | log("channel_lookup: %d: bad id", id); | |
150 | return NULL; | |
151 | } | |
152 | c = channels[id]; | |
153 | if (c == NULL) { | |
154 | log("channel_lookup: %d: bad id: channel free", id); | |
155 | return NULL; | |
156 | } | |
157 | return c; | |
158 | } | |
159 | ||
160 | /* | |
161 | * Register filedescriptors for a channel, used when allocating a channel or | |
162 | * when the channel consumer/producer is ready, e.g. shell exec'd | |
163 | */ | |
164 | ||
165 | static void | |
166 | channel_register_fds(Channel *c, int rfd, int wfd, int efd, | |
167 | int extusage, int nonblock) | |
168 | { | |
169 | /* Update the maximum file descriptor value. */ | |
170 | channel_max_fd = MAX(channel_max_fd, rfd); | |
171 | channel_max_fd = MAX(channel_max_fd, wfd); | |
172 | channel_max_fd = MAX(channel_max_fd, efd); | |
173 | ||
174 | /* XXX set close-on-exec -markus */ | |
175 | ||
176 | c->rfd = rfd; | |
177 | c->wfd = wfd; | |
178 | c->sock = (rfd == wfd) ? rfd : -1; | |
179 | c->efd = efd; | |
180 | c->extended_usage = extusage; | |
181 | ||
182 | /* XXX ugly hack: nonblock is only set by the server */ | |
183 | if (nonblock && isatty(c->rfd)) { | |
184 | debug("channel %d: rfd %d isatty", c->self, c->rfd); | |
185 | c->isatty = 1; | |
186 | if (!isatty(c->wfd)) { | |
187 | error("channel %d: wfd %d is not a tty?", | |
188 | c->self, c->wfd); | |
189 | } | |
190 | } else { | |
191 | c->isatty = 0; | |
192 | } | |
193 | ||
194 | /* enable nonblocking mode */ | |
195 | if (nonblock) { | |
196 | if (rfd != -1) | |
197 | set_nonblock(rfd); | |
198 | if (wfd != -1) | |
199 | set_nonblock(wfd); | |
200 | if (efd != -1) | |
201 | set_nonblock(efd); | |
202 | } | |
203 | } | |
204 | ||
205 | /* | |
206 | * Allocate a new channel object and set its type and socket. This will cause | |
207 | * remote_name to be freed. | |
208 | */ | |
209 | ||
210 | Channel * | |
211 | channel_new(char *ctype, int type, int rfd, int wfd, int efd, | |
212 | int window, int maxpack, int extusage, char *remote_name, int nonblock) | |
213 | { | |
214 | int i, found; | |
215 | Channel *c; | |
216 | ||
217 | /* Do initial allocation if this is the first call. */ | |
218 | if (channels_alloc == 0) { | |
219 | chan_init(); | |
220 | channels_alloc = 10; | |
221 | channels = xmalloc(channels_alloc * sizeof(Channel *)); | |
222 | for (i = 0; i < channels_alloc; i++) | |
223 | channels[i] = NULL; | |
224 | fatal_add_cleanup((void (*) (void *)) channel_free_all, NULL); | |
225 | } | |
226 | /* Try to find a free slot where to put the new channel. */ | |
227 | for (found = -1, i = 0; i < channels_alloc; i++) | |
228 | if (channels[i] == NULL) { | |
229 | /* Found a free slot. */ | |
230 | found = i; | |
231 | break; | |
232 | } | |
233 | if (found == -1) { | |
234 | /* There are no free slots. Take last+1 slot and expand the array. */ | |
235 | found = channels_alloc; | |
236 | channels_alloc += 10; | |
237 | debug2("channel: expanding %d", channels_alloc); | |
238 | channels = xrealloc(channels, channels_alloc * sizeof(Channel *)); | |
239 | for (i = found; i < channels_alloc; i++) | |
240 | channels[i] = NULL; | |
241 | } | |
242 | /* Initialize and return new channel. */ | |
243 | c = channels[found] = xmalloc(sizeof(Channel)); | |
244 | memset(c, 0, sizeof(Channel)); | |
245 | buffer_init(&c->input); | |
246 | buffer_init(&c->output); | |
247 | buffer_init(&c->extended); | |
248 | chan_init_iostates(c); | |
249 | channel_register_fds(c, rfd, wfd, efd, extusage, nonblock); | |
250 | c->self = found; | |
251 | c->type = type; | |
252 | c->ctype = ctype; | |
253 | c->local_window = window; | |
254 | c->local_window_max = window; | |
255 | c->local_consumed = 0; | |
256 | c->local_maxpacket = maxpack; | |
257 | c->remote_id = -1; | |
258 | c->remote_name = remote_name; | |
259 | c->remote_window = 0; | |
260 | c->remote_maxpacket = 0; | |
261 | c->cb_fn = NULL; | |
262 | c->cb_arg = NULL; | |
263 | c->cb_event = 0; | |
264 | c->force_drain = 0; | |
265 | c->detach_user = NULL; | |
266 | c->input_filter = NULL; | |
267 | debug("channel %d: new [%s]", found, remote_name); | |
268 | return c; | |
269 | } | |
270 | ||
271 | static int | |
272 | channel_find_maxfd(void) | |
273 | { | |
274 | int i, max = 0; | |
275 | Channel *c; | |
276 | ||
277 | for (i = 0; i < channels_alloc; i++) { | |
278 | c = channels[i]; | |
279 | if (c != NULL) { | |
280 | max = MAX(max, c->rfd); | |
281 | max = MAX(max, c->wfd); | |
282 | max = MAX(max, c->efd); | |
283 | } | |
284 | } | |
285 | return max; | |
286 | } | |
287 | ||
288 | int | |
289 | channel_close_fd(int *fdp) | |
290 | { | |
291 | int ret = 0, fd = *fdp; | |
292 | ||
293 | if (fd != -1) { | |
294 | ret = close(fd); | |
295 | *fdp = -1; | |
296 | if (fd == channel_max_fd) | |
297 | channel_max_fd = channel_find_maxfd(); | |
298 | } | |
299 | return ret; | |
300 | } | |
301 | ||
302 | /* Close all channel fd/socket. */ | |
303 | ||
304 | static void | |
305 | channel_close_fds(Channel *c) | |
306 | { | |
307 | debug3("channel_close_fds: channel %d: r %d w %d e %d", | |
308 | c->self, c->rfd, c->wfd, c->efd); | |
309 | ||
310 | channel_close_fd(&c->sock); | |
311 | channel_close_fd(&c->rfd); | |
312 | channel_close_fd(&c->wfd); | |
313 | channel_close_fd(&c->efd); | |
314 | } | |
315 | ||
316 | /* Free the channel and close its fd/socket. */ | |
317 | ||
318 | void | |
319 | channel_free(Channel *c) | |
320 | { | |
321 | char *s; | |
322 | int i, n; | |
323 | ||
324 | for (n = 0, i = 0; i < channels_alloc; i++) | |
325 | if (channels[i]) | |
326 | n++; | |
327 | debug("channel_free: channel %d: %s, nchannels %d", c->self, | |
328 | c->remote_name ? c->remote_name : "???", n); | |
329 | ||
330 | s = channel_open_message(); | |
331 | debug3("channel_free: status: %s", s); | |
332 | xfree(s); | |
333 | ||
334 | if (c->sock != -1) | |
335 | shutdown(c->sock, SHUT_RDWR); | |
336 | channel_close_fds(c); | |
337 | buffer_free(&c->input); | |
338 | buffer_free(&c->output); | |
339 | buffer_free(&c->extended); | |
340 | if (c->remote_name) { | |
341 | xfree(c->remote_name); | |
342 | c->remote_name = NULL; | |
343 | } | |
344 | channels[c->self] = NULL; | |
345 | xfree(c); | |
346 | } | |
347 | ||
348 | void | |
349 | channel_free_all(void) | |
350 | { | |
351 | int i; | |
352 | ||
353 | for (i = 0; i < channels_alloc; i++) | |
354 | if (channels[i] != NULL) | |
355 | channel_free(channels[i]); | |
356 | } | |
357 | ||
358 | /* | |
359 | * Closes the sockets/fds of all channels. This is used to close extra file | |
360 | * descriptors after a fork. | |
361 | */ | |
362 | ||
363 | void | |
364 | channel_close_all() | |
365 | { | |
366 | int i; | |
367 | ||
368 | for (i = 0; i < channels_alloc; i++) | |
369 | if (channels[i] != NULL) | |
370 | channel_close_fds(channels[i]); | |
371 | } | |
372 | ||
373 | /* | |
374 | * Stop listening to channels. | |
375 | */ | |
376 | ||
377 | void | |
378 | channel_stop_listening(void) | |
379 | { | |
380 | int i; | |
381 | Channel *c; | |
382 | ||
383 | for (i = 0; i < channels_alloc; i++) { | |
384 | c = channels[i]; | |
385 | if (c != NULL) { | |
386 | switch (c->type) { | |
387 | case SSH_CHANNEL_AUTH_SOCKET: | |
388 | case SSH_CHANNEL_PORT_LISTENER: | |
389 | case SSH_CHANNEL_RPORT_LISTENER: | |
390 | case SSH_CHANNEL_X11_LISTENER: | |
391 | channel_close_fd(&c->sock); | |
392 | channel_free(c); | |
393 | break; | |
394 | } | |
395 | } | |
396 | } | |
397 | } | |
398 | ||
399 | /* | |
400 | * Returns true if no channel has too much buffered data, and false if one or | |
401 | * more channel is overfull. | |
402 | */ | |
403 | ||
404 | int | |
405 | channel_not_very_much_buffered_data() | |
406 | { | |
407 | u_int i; | |
408 | Channel *c; | |
409 | ||
410 | for (i = 0; i < channels_alloc; i++) { | |
411 | c = channels[i]; | |
412 | if (c != NULL && c->type == SSH_CHANNEL_OPEN) { | |
413 | #if 0 | |
414 | if (!compat20 && | |
415 | buffer_len(&c->input) > packet_get_maxsize()) { | |
416 | debug("channel %d: big input buffer %d", | |
417 | c->self, buffer_len(&c->input)); | |
418 | return 0; | |
419 | } | |
420 | #endif | |
421 | if (buffer_len(&c->output) > packet_get_maxsize()) { | |
422 | debug("channel %d: big output buffer %d > %d", | |
423 | c->self, buffer_len(&c->output), | |
424 | packet_get_maxsize()); | |
425 | return 0; | |
426 | } | |
427 | } | |
428 | } | |
429 | return 1; | |
430 | } | |
431 | ||
432 | /* Returns true if any channel is still open. */ | |
433 | ||
434 | int | |
435 | channel_still_open() | |
436 | { | |
437 | int i; | |
438 | Channel *c; | |
439 | ||
440 | for (i = 0; i < channels_alloc; i++) { | |
441 | c = channels[i]; | |
442 | if (c == NULL) | |
443 | continue; | |
444 | switch (c->type) { | |
445 | case SSH_CHANNEL_X11_LISTENER: | |
446 | case SSH_CHANNEL_PORT_LISTENER: | |
447 | case SSH_CHANNEL_RPORT_LISTENER: | |
448 | case SSH_CHANNEL_CLOSED: | |
449 | case SSH_CHANNEL_AUTH_SOCKET: | |
450 | case SSH_CHANNEL_DYNAMIC: | |
451 | case SSH_CHANNEL_CONNECTING: | |
452 | case SSH_CHANNEL_ZOMBIE: | |
453 | continue; | |
454 | case SSH_CHANNEL_LARVAL: | |
455 | if (!compat20) | |
456 | fatal("cannot happen: SSH_CHANNEL_LARVAL"); | |
457 | continue; | |
458 | case SSH_CHANNEL_OPENING: | |
459 | case SSH_CHANNEL_OPEN: | |
460 | case SSH_CHANNEL_X11_OPEN: | |
461 | return 1; | |
462 | case SSH_CHANNEL_INPUT_DRAINING: | |
463 | case SSH_CHANNEL_OUTPUT_DRAINING: | |
464 | if (!compat13) | |
465 | fatal("cannot happen: OUT_DRAIN"); | |
466 | return 1; | |
467 | default: | |
468 | fatal("channel_still_open: bad channel type %d", c->type); | |
469 | /* NOTREACHED */ | |
470 | } | |
471 | } | |
472 | return 0; | |
473 | } | |
474 | ||
475 | /* Returns the id of an open channel suitable for keepaliving */ | |
476 | ||
477 | int | |
478 | channel_find_open() | |
479 | { | |
480 | int i; | |
481 | Channel *c; | |
482 | ||
483 | for (i = 0; i < channels_alloc; i++) { | |
484 | c = channels[i]; | |
485 | if (c == NULL) | |
486 | continue; | |
487 | switch (c->type) { | |
488 | case SSH_CHANNEL_CLOSED: | |
489 | case SSH_CHANNEL_DYNAMIC: | |
490 | case SSH_CHANNEL_X11_LISTENER: | |
491 | case SSH_CHANNEL_PORT_LISTENER: | |
492 | case SSH_CHANNEL_RPORT_LISTENER: | |
493 | case SSH_CHANNEL_OPENING: | |
494 | case SSH_CHANNEL_CONNECTING: | |
495 | case SSH_CHANNEL_ZOMBIE: | |
496 | continue; | |
497 | case SSH_CHANNEL_LARVAL: | |
498 | case SSH_CHANNEL_AUTH_SOCKET: | |
499 | case SSH_CHANNEL_OPEN: | |
500 | case SSH_CHANNEL_X11_OPEN: | |
501 | return i; | |
502 | case SSH_CHANNEL_INPUT_DRAINING: | |
503 | case SSH_CHANNEL_OUTPUT_DRAINING: | |
504 | if (!compat13) | |
505 | fatal("cannot happen: OUT_DRAIN"); | |
506 | return i; | |
507 | default: | |
508 | fatal("channel_find_open: bad channel type %d", c->type); | |
509 | /* NOTREACHED */ | |
510 | } | |
511 | } | |
512 | return -1; | |
513 | } | |
514 | ||
515 | ||
516 | /* | |
517 | * Returns a message describing the currently open forwarded connections, | |
518 | * suitable for sending to the client. The message contains crlf pairs for | |
519 | * newlines. | |
520 | */ | |
521 | ||
522 | char * | |
523 | channel_open_message() | |
524 | { | |
525 | Buffer buffer; | |
526 | Channel *c; | |
527 | char buf[1024], *cp; | |
528 | int i; | |
529 | ||
530 | buffer_init(&buffer); | |
531 | snprintf(buf, sizeof buf, "The following connections are open:\r\n"); | |
532 | buffer_append(&buffer, buf, strlen(buf)); | |
533 | for (i = 0; i < channels_alloc; i++) { | |
534 | c = channels[i]; | |
535 | if (c == NULL) | |
536 | continue; | |
537 | switch (c->type) { | |
538 | case SSH_CHANNEL_X11_LISTENER: | |
539 | case SSH_CHANNEL_PORT_LISTENER: | |
540 | case SSH_CHANNEL_RPORT_LISTENER: | |
541 | case SSH_CHANNEL_CLOSED: | |
542 | case SSH_CHANNEL_AUTH_SOCKET: | |
543 | case SSH_CHANNEL_ZOMBIE: | |
544 | continue; | |
545 | case SSH_CHANNEL_LARVAL: | |
546 | case SSH_CHANNEL_OPENING: | |
547 | case SSH_CHANNEL_CONNECTING: | |
548 | case SSH_CHANNEL_DYNAMIC: | |
549 | case SSH_CHANNEL_OPEN: | |
550 | case SSH_CHANNEL_X11_OPEN: | |
551 | case SSH_CHANNEL_INPUT_DRAINING: | |
552 | case SSH_CHANNEL_OUTPUT_DRAINING: | |
553 | snprintf(buf, sizeof buf, " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d)\r\n", | |
554 | c->self, c->remote_name, | |
555 | c->type, c->remote_id, | |
556 | c->istate, buffer_len(&c->input), | |
557 | c->ostate, buffer_len(&c->output), | |
558 | c->rfd, c->wfd); | |
559 | buffer_append(&buffer, buf, strlen(buf)); | |
560 | continue; | |
561 | default: | |
562 | fatal("channel_open_message: bad channel type %d", c->type); | |
563 | /* NOTREACHED */ | |
564 | } | |
565 | } | |
566 | buffer_append(&buffer, "\0", 1); | |
567 | cp = xstrdup(buffer_ptr(&buffer)); | |
568 | buffer_free(&buffer); | |
569 | return cp; | |
570 | } | |
571 | ||
572 | void | |
573 | channel_send_open(int id) | |
574 | { | |
575 | Channel *c = channel_lookup(id); | |
576 | if (c == NULL) { | |
577 | log("channel_send_open: %d: bad id", id); | |
578 | return; | |
579 | } | |
580 | debug("send channel open %d", id); | |
581 | packet_start(SSH2_MSG_CHANNEL_OPEN); | |
582 | packet_put_cstring(c->ctype); | |
583 | packet_put_int(c->self); | |
584 | packet_put_int(c->local_window); | |
585 | packet_put_int(c->local_maxpacket); | |
586 | packet_send(); | |
587 | } | |
588 | ||
589 | void | |
590 | channel_request(int id, char *service, int wantconfirm) | |
591 | { | |
592 | channel_request_start(id, service, wantconfirm); | |
593 | packet_send(); | |
594 | debug("channel request %d: %s", id, service) ; | |
595 | } | |
596 | void | |
597 | channel_request_start(int id, char *service, int wantconfirm) | |
598 | { | |
599 | Channel *c = channel_lookup(id); | |
600 | if (c == NULL) { | |
601 | log("channel_request: %d: bad id", id); | |
602 | return; | |
603 | } | |
604 | packet_start(SSH2_MSG_CHANNEL_REQUEST); | |
605 | packet_put_int(c->remote_id); | |
606 | packet_put_cstring(service); | |
607 | packet_put_char(wantconfirm); | |
608 | } | |
609 | void | |
610 | channel_register_callback(int id, int mtype, channel_callback_fn *fn, void *arg) | |
611 | { | |
612 | Channel *c = channel_lookup(id); | |
613 | if (c == NULL) { | |
614 | log("channel_register_callback: %d: bad id", id); | |
615 | return; | |
616 | } | |
617 | c->cb_event = mtype; | |
618 | c->cb_fn = fn; | |
619 | c->cb_arg = arg; | |
620 | } | |
621 | void | |
622 | channel_register_cleanup(int id, channel_callback_fn *fn) | |
623 | { | |
624 | Channel *c = channel_lookup(id); | |
625 | if (c == NULL) { | |
626 | log("channel_register_cleanup: %d: bad id", id); | |
627 | return; | |
628 | } | |
629 | c->detach_user = fn; | |
630 | } | |
631 | void | |
632 | channel_cancel_cleanup(int id) | |
633 | { | |
634 | Channel *c = channel_lookup(id); | |
635 | if (c == NULL) { | |
636 | log("channel_cancel_cleanup: %d: bad id", id); | |
637 | return; | |
638 | } | |
639 | c->detach_user = NULL; | |
640 | } | |
641 | void | |
642 | channel_register_filter(int id, channel_filter_fn *fn) | |
643 | { | |
644 | Channel *c = channel_lookup(id); | |
645 | if (c == NULL) { | |
646 | log("channel_register_filter: %d: bad id", id); | |
647 | return; | |
648 | } | |
649 | c->input_filter = fn; | |
650 | } | |
651 | ||
652 | void | |
653 | channel_set_fds(int id, int rfd, int wfd, int efd, | |
654 | int extusage, int nonblock) | |
655 | { | |
656 | Channel *c = channel_lookup(id); | |
657 | if (c == NULL || c->type != SSH_CHANNEL_LARVAL) | |
658 | fatal("channel_activate for non-larval channel %d.", id); | |
659 | channel_register_fds(c, rfd, wfd, efd, extusage, nonblock); | |
660 | c->type = SSH_CHANNEL_OPEN; | |
661 | /* XXX window size? */ | |
662 | c->local_window = c->local_window_max = c->local_maxpacket * 2; | |
663 | packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST); | |
664 | packet_put_int(c->remote_id); | |
665 | packet_put_int(c->local_window); | |
666 | packet_send(); | |
667 | } | |
668 | ||
669 | /* | |
670 | * 'channel_pre*' are called just before select() to add any bits relevant to | |
671 | * channels in the select bitmasks. | |
672 | */ | |
673 | /* | |
674 | * 'channel_post*': perform any appropriate operations for channels which | |
675 | * have events pending. | |
676 | */ | |
677 | typedef void chan_fn(Channel *c, fd_set * readset, fd_set * writeset); | |
678 | chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE]; | |
679 | chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE]; | |
680 | ||
681 | static void | |
682 | channel_pre_listener(Channel *c, fd_set * readset, fd_set * writeset) | |
683 | { | |
684 | FD_SET(c->sock, readset); | |
685 | } | |
686 | ||
687 | static void | |
688 | channel_pre_connecting(Channel *c, fd_set * readset, fd_set * writeset) | |
689 | { | |
690 | debug3("channel %d: waiting for connection", c->self); | |
691 | FD_SET(c->sock, writeset); | |
692 | } | |
693 | ||
694 | static void | |
695 | channel_pre_open_13(Channel *c, fd_set * readset, fd_set * writeset) | |
696 | { | |
697 | if (buffer_len(&c->input) < packet_get_maxsize()) | |
698 | FD_SET(c->sock, readset); | |
699 | if (buffer_len(&c->output) > 0) | |
700 | FD_SET(c->sock, writeset); | |
701 | } | |
702 | ||
703 | static void | |
704 | channel_pre_open_15(Channel *c, fd_set * readset, fd_set * writeset) | |
705 | { | |
706 | /* test whether sockets are 'alive' for read/write */ | |
707 | if (c->istate == CHAN_INPUT_OPEN) | |
708 | if (buffer_len(&c->input) < packet_get_maxsize()) | |
709 | FD_SET(c->sock, readset); | |
710 | if (c->ostate == CHAN_OUTPUT_OPEN || | |
711 | c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { | |
712 | if (buffer_len(&c->output) > 0) { | |
713 | FD_SET(c->sock, writeset); | |
714 | } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { | |
715 | chan_obuf_empty(c); | |
716 | } | |
717 | } | |
718 | } | |
719 | ||
720 | static void | |
721 | channel_pre_open_20(Channel *c, fd_set * readset, fd_set * writeset) | |
722 | { | |
723 | if (c->istate == CHAN_INPUT_OPEN && | |
724 | c->remote_window > 0 && | |
725 | buffer_len(&c->input) < c->remote_window) | |
726 | FD_SET(c->rfd, readset); | |
727 | if (c->ostate == CHAN_OUTPUT_OPEN || | |
728 | c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { | |
729 | if (buffer_len(&c->output) > 0) { | |
730 | FD_SET(c->wfd, writeset); | |
731 | } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { | |
732 | chan_obuf_empty(c); | |
733 | } | |
734 | } | |
735 | /** XXX check close conditions, too */ | |
736 | if (c->efd != -1) { | |
737 | if (c->extended_usage == CHAN_EXTENDED_WRITE && | |
738 | buffer_len(&c->extended) > 0) | |
739 | FD_SET(c->efd, writeset); | |
740 | else if (c->extended_usage == CHAN_EXTENDED_READ && | |
741 | buffer_len(&c->extended) < c->remote_window) | |
742 | FD_SET(c->efd, readset); | |
743 | } | |
744 | } | |
745 | ||
746 | static void | |
747 | channel_pre_input_draining(Channel *c, fd_set * readset, fd_set * writeset) | |
748 | { | |
749 | if (buffer_len(&c->input) == 0) { | |
750 | packet_start(SSH_MSG_CHANNEL_CLOSE); | |
751 | packet_put_int(c->remote_id); | |
752 | packet_send(); | |
753 | c->type = SSH_CHANNEL_CLOSED; | |
754 | debug("channel %d: closing after input drain.", c->self); | |
755 | } | |
756 | } | |
757 | ||
758 | static void | |
759 | channel_pre_output_draining(Channel *c, fd_set * readset, fd_set * writeset) | |
760 | { | |
761 | if (buffer_len(&c->output) == 0) | |
762 | chan_mark_dead(c); | |
763 | else | |
764 | FD_SET(c->sock, writeset); | |
765 | } | |
766 | ||
767 | /* | |
768 | * This is a special state for X11 authentication spoofing. An opened X11 | |
769 | * connection (when authentication spoofing is being done) remains in this | |
770 | * state until the first packet has been completely read. The authentication | |
771 | * data in that packet is then substituted by the real data if it matches the | |
772 | * fake data, and the channel is put into normal mode. | |
773 | * XXX All this happens at the client side. | |
774 | * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok | |
775 | */ | |
776 | static int | |
777 | x11_open_helper(Buffer *b) | |
778 | { | |
779 | u_char *ucp; | |
780 | u_int proto_len, data_len; | |
781 | ||
782 | /* Check if the fixed size part of the packet is in buffer. */ | |
783 | if (buffer_len(b) < 12) | |
784 | return 0; | |
785 | ||
786 | /* Parse the lengths of variable-length fields. */ | |
787 | ucp = (u_char *) buffer_ptr(b); | |
788 | if (ucp[0] == 0x42) { /* Byte order MSB first. */ | |
789 | proto_len = 256 * ucp[6] + ucp[7]; | |
790 | data_len = 256 * ucp[8] + ucp[9]; | |
791 | } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */ | |
792 | proto_len = ucp[6] + 256 * ucp[7]; | |
793 | data_len = ucp[8] + 256 * ucp[9]; | |
794 | } else { | |
795 | debug("Initial X11 packet contains bad byte order byte: 0x%x", | |
796 | ucp[0]); | |
797 | return -1; | |
798 | } | |
799 | ||
800 | /* Check if the whole packet is in buffer. */ | |
801 | if (buffer_len(b) < | |
802 | 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3)) | |
803 | return 0; | |
804 | ||
805 | /* Check if authentication protocol matches. */ | |
806 | if (proto_len != strlen(x11_saved_proto) || | |
807 | memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) { | |
808 | debug("X11 connection uses different authentication protocol."); | |
809 | return -1; | |
810 | } | |
811 | /* Check if authentication data matches our fake data. */ | |
812 | if (data_len != x11_fake_data_len || | |
813 | memcmp(ucp + 12 + ((proto_len + 3) & ~3), | |
814 | x11_fake_data, x11_fake_data_len) != 0) { | |
815 | debug("X11 auth data does not match fake data."); | |
816 | return -1; | |
817 | } | |
818 | /* Check fake data length */ | |
819 | if (x11_fake_data_len != x11_saved_data_len) { | |
820 | error("X11 fake_data_len %d != saved_data_len %d", | |
821 | x11_fake_data_len, x11_saved_data_len); | |
822 | return -1; | |
823 | } | |
824 | /* | |
825 | * Received authentication protocol and data match | |
826 | * our fake data. Substitute the fake data with real | |
827 | * data. | |
828 | */ | |
829 | memcpy(ucp + 12 + ((proto_len + 3) & ~3), | |
830 | x11_saved_data, x11_saved_data_len); | |
831 | return 1; | |
832 | } | |
833 | ||
834 | static void | |
835 | channel_pre_x11_open_13(Channel *c, fd_set * readset, fd_set * writeset) | |
836 | { | |
837 | int ret = x11_open_helper(&c->output); | |
838 | if (ret == 1) { | |
839 | /* Start normal processing for the channel. */ | |
840 | c->type = SSH_CHANNEL_OPEN; | |
841 | channel_pre_open_13(c, readset, writeset); | |
842 | } else if (ret == -1) { | |
843 | /* | |
844 | * We have received an X11 connection that has bad | |
845 | * authentication information. | |
846 | */ | |
847 | log("X11 connection rejected because of wrong authentication."); | |
848 | buffer_clear(&c->input); | |
849 | buffer_clear(&c->output); | |
850 | channel_close_fd(&c->sock); | |
851 | c->sock = -1; | |
852 | c->type = SSH_CHANNEL_CLOSED; | |
853 | packet_start(SSH_MSG_CHANNEL_CLOSE); | |
854 | packet_put_int(c->remote_id); | |
855 | packet_send(); | |
856 | } | |
857 | } | |
858 | ||
859 | static void | |
860 | channel_pre_x11_open(Channel *c, fd_set * readset, fd_set * writeset) | |
861 | { | |
862 | int ret = x11_open_helper(&c->output); | |
863 | ||
864 | /* c->force_drain = 1; */ | |
865 | ||
866 | if (ret == 1) { | |
867 | c->type = SSH_CHANNEL_OPEN; | |
868 | if (compat20) | |
869 | channel_pre_open_20(c, readset, writeset); | |
870 | else | |
871 | channel_pre_open_15(c, readset, writeset); | |
872 | } else if (ret == -1) { | |
873 | debug("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate); | |
874 | chan_read_failed(c); /** force close? */ | |
875 | chan_write_failed(c); | |
876 | debug("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate); | |
877 | } | |
878 | } | |
879 | ||
880 | /* try to decode a socks4 header */ | |
881 | static int | |
882 | channel_decode_socks4(Channel *c, fd_set * readset, fd_set * writeset) | |
883 | { | |
884 | u_char *p, *host; | |
885 | int len, have, i, found; | |
886 | char username[256]; | |
887 | struct { | |
888 | u_int8_t version; | |
889 | u_int8_t command; | |
890 | u_int16_t dest_port; | |
891 | struct in_addr dest_addr; | |
892 | } s4_req, s4_rsp; | |
893 | ||
894 | debug2("channel %d: decode socks4", c->self); | |
895 | ||
896 | have = buffer_len(&c->input); | |
897 | len = sizeof(s4_req); | |
898 | if (have < len) | |
899 | return 0; | |
900 | p = buffer_ptr(&c->input); | |
901 | for (found = 0, i = len; i < have; i++) { | |
902 | if (p[i] == '\0') { | |
903 | found = 1; | |
904 | break; | |
905 | } | |
906 | if (i > 1024) { | |
907 | /* the peer is probably sending garbage */ | |
908 | debug("channel %d: decode socks4: too long", | |
909 | c->self); | |
910 | return -1; | |
911 | } | |
912 | } | |
913 | if (!found) | |
914 | return 0; | |
915 | buffer_get(&c->input, (char *)&s4_req.version, 1); | |
916 | buffer_get(&c->input, (char *)&s4_req.command, 1); | |
917 | buffer_get(&c->input, (char *)&s4_req.dest_port, 2); | |
918 | buffer_get(&c->input, (char *)&s4_req.dest_addr, 4); | |
919 | have = buffer_len(&c->input); | |
920 | p = buffer_ptr(&c->input); | |
921 | len = strlen(p); | |
922 | debug2("channel %d: decode socks4: user %s/%d", c->self, p, len); | |
923 | if (len > have) | |
924 | fatal("channel %d: decode socks4: len %d > have %d", | |
925 | c->self, len, have); | |
926 | strlcpy(username, p, sizeof(username)); | |
927 | buffer_consume(&c->input, len); | |
928 | buffer_consume(&c->input, 1); /* trailing '\0' */ | |
929 | ||
930 | host = inet_ntoa(s4_req.dest_addr); | |
931 | strlcpy(c->path, host, sizeof(c->path)); | |
932 | c->host_port = ntohs(s4_req.dest_port); | |
933 | ||
934 | debug("channel %d: dynamic request: socks4 host %s port %u command %u", | |
935 | c->self, host, c->host_port, s4_req.command); | |
936 | ||
937 | if (s4_req.command != 1) { | |
938 | debug("channel %d: cannot handle: socks4 cn %d", | |
939 | c->self, s4_req.command); | |
940 | return -1; | |
941 | } | |
942 | s4_rsp.version = 0; /* vn: 0 for reply */ | |
943 | s4_rsp.command = 90; /* cd: req granted */ | |
944 | s4_rsp.dest_port = 0; /* ignored */ | |
945 | s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */ | |
946 | buffer_append(&c->output, (char *)&s4_rsp, sizeof(s4_rsp)); | |
947 | return 1; | |
948 | } | |
949 | ||
950 | /* dynamic port forwarding */ | |
951 | static void | |
952 | channel_pre_dynamic(Channel *c, fd_set * readset, fd_set * writeset) | |
953 | { | |
954 | u_char *p; | |
955 | int have, ret; | |
956 | ||
957 | have = buffer_len(&c->input); | |
958 | c->delayed = 0; | |
959 | debug2("channel %d: pre_dynamic: have %d", c->self, have); | |
960 | /* buffer_dump(&c->input); */ | |
961 | /* check if the fixed size part of the packet is in buffer. */ | |
962 | if (have < 4) { | |
963 | /* need more */ | |
964 | FD_SET(c->sock, readset); | |
965 | return; | |
966 | } | |
967 | /* try to guess the protocol */ | |
968 | p = buffer_ptr(&c->input); | |
969 | switch (p[0]) { | |
970 | case 0x04: | |
971 | ret = channel_decode_socks4(c, readset, writeset); | |
972 | break; | |
973 | default: | |
974 | ret = -1; | |
975 | break; | |
976 | } | |
977 | if (ret < 0) { | |
978 | chan_mark_dead(c); | |
979 | } else if (ret == 0) { | |
980 | debug2("channel %d: pre_dynamic: need more", c->self); | |
981 | /* need more */ | |
982 | FD_SET(c->sock, readset); | |
983 | } else { | |
984 | /* switch to the next state */ | |
985 | c->type = SSH_CHANNEL_OPENING; | |
986 | port_open_helper(c, "direct-tcpip"); | |
987 | } | |
988 | } | |
989 | ||
990 | /* This is our fake X11 server socket. */ | |
991 | static void | |
992 | channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset) | |
993 | { | |
994 | Channel *nc; | |
995 | struct sockaddr addr; | |
996 | int newsock; | |
997 | socklen_t addrlen; | |
998 | char buf[16384], *remote_ipaddr; | |
999 | int remote_port; | |
1000 | ||
1001 | if (FD_ISSET(c->sock, readset)) { | |
1002 | debug("X11 connection requested."); | |
1003 | addrlen = sizeof(addr); | |
1004 | newsock = accept(c->sock, &addr, &addrlen); | |
1005 | if (newsock < 0) { | |
1006 | error("accept: %.100s", strerror(errno)); | |
1007 | return; | |
1008 | } | |
1009 | remote_ipaddr = get_peer_ipaddr(newsock); | |
1010 | remote_port = get_peer_port(newsock); | |
1011 | snprintf(buf, sizeof buf, "X11 connection from %.200s port %d", | |
1012 | remote_ipaddr, remote_port); | |
1013 | ||
1014 | nc = channel_new("accepted x11 socket", | |
1015 | SSH_CHANNEL_OPENING, newsock, newsock, -1, | |
1016 | c->local_window_max, c->local_maxpacket, | |
1017 | 0, xstrdup(buf), 1); | |
1018 | if (nc == NULL) { | |
1019 | close(newsock); | |
1020 | xfree(remote_ipaddr); | |
1021 | return; | |
1022 | } | |
1023 | if (compat20) { | |
1024 | packet_start(SSH2_MSG_CHANNEL_OPEN); | |
1025 | packet_put_cstring("x11"); | |
1026 | packet_put_int(nc->self); | |
1027 | packet_put_int(c->local_window_max); | |
1028 | packet_put_int(c->local_maxpacket); | |
1029 | /* originator ipaddr and port */ | |
1030 | packet_put_cstring(remote_ipaddr); | |
1031 | if (datafellows & SSH_BUG_X11FWD) { | |
1032 | debug("ssh2 x11 bug compat mode"); | |
1033 | } else { | |
1034 | packet_put_int(remote_port); | |
1035 | } | |
1036 | packet_send(); | |
1037 | } else { | |
1038 | packet_start(SSH_SMSG_X11_OPEN); | |
1039 | packet_put_int(nc->self); | |
1040 | if (packet_get_protocol_flags() & | |
1041 | SSH_PROTOFLAG_HOST_IN_FWD_OPEN) | |
1042 | packet_put_cstring(buf); | |
1043 | packet_send(); | |
1044 | } | |
1045 | xfree(remote_ipaddr); | |
1046 | } | |
1047 | } | |
1048 | ||
1049 | static void | |
1050 | port_open_helper(Channel *c, char *rtype) | |
1051 | { | |
1052 | int direct; | |
1053 | char buf[1024]; | |
1054 | char *remote_ipaddr = get_peer_ipaddr(c->sock); | |
1055 | u_short remote_port = get_peer_port(c->sock); | |
1056 | ||
1057 | direct = (strcmp(rtype, "direct-tcpip") == 0); | |
1058 | ||
1059 | snprintf(buf, sizeof buf, | |
1060 | "%s: listening port %d for %.100s port %d, " | |
1061 | "connect from %.200s port %d", | |
1062 | rtype, c->listening_port, c->path, c->host_port, | |
1063 | remote_ipaddr, remote_port); | |
1064 | ||
1065 | xfree(c->remote_name); | |
1066 | c->remote_name = xstrdup(buf); | |
1067 | ||
1068 | if (compat20) { | |
1069 | packet_start(SSH2_MSG_CHANNEL_OPEN); | |
1070 | packet_put_cstring(rtype); | |
1071 | packet_put_int(c->self); | |
1072 | packet_put_int(c->local_window_max); | |
1073 | packet_put_int(c->local_maxpacket); | |
1074 | if (direct) { | |
1075 | /* target host, port */ | |
1076 | packet_put_cstring(c->path); | |
1077 | packet_put_int(c->host_port); | |
1078 | } else { | |
1079 | /* listen address, port */ | |
1080 | packet_put_cstring(c->path); | |
1081 | packet_put_int(c->listening_port); | |
1082 | } | |
1083 | /* originator host and port */ | |
1084 | packet_put_cstring(remote_ipaddr); | |
1085 | packet_put_int(remote_port); | |
1086 | packet_send(); | |
1087 | } else { | |
1088 | packet_start(SSH_MSG_PORT_OPEN); | |
1089 | packet_put_int(c->self); | |
1090 | packet_put_cstring(c->path); | |
1091 | packet_put_int(c->host_port); | |
1092 | if (packet_get_protocol_flags() & | |
1093 | SSH_PROTOFLAG_HOST_IN_FWD_OPEN) | |
1094 | packet_put_cstring(c->remote_name); | |
1095 | packet_send(); | |
1096 | } | |
1097 | xfree(remote_ipaddr); | |
1098 | } | |
1099 | ||
1100 | /* | |
1101 | * This socket is listening for connections to a forwarded TCP/IP port. | |
1102 | */ | |
1103 | static void | |
1104 | channel_post_port_listener(Channel *c, fd_set * readset, fd_set * writeset) | |
1105 | { | |
1106 | Channel *nc; | |
1107 | struct sockaddr addr; | |
1108 | int newsock, nextstate; | |
1109 | socklen_t addrlen; | |
1110 | char *rtype; | |
1111 | ||
1112 | if (FD_ISSET(c->sock, readset)) { | |
1113 | debug("Connection to port %d forwarding " | |
1114 | "to %.100s port %d requested.", | |
1115 | c->listening_port, c->path, c->host_port); | |
1116 | ||
1117 | if (c->type == SSH_CHANNEL_RPORT_LISTENER) { | |
1118 | nextstate = SSH_CHANNEL_OPENING; | |
1119 | rtype = "forwarded-tcpip"; | |
1120 | } else { | |
1121 | if (c->host_port == 0) { | |
1122 | nextstate = SSH_CHANNEL_DYNAMIC; | |
1123 | rtype = "dynamic-tcpip"; | |
1124 | } else { | |
1125 | nextstate = SSH_CHANNEL_OPENING; | |
1126 | rtype = "direct-tcpip"; | |
1127 | } | |
1128 | } | |
1129 | ||
1130 | addrlen = sizeof(addr); | |
1131 | newsock = accept(c->sock, &addr, &addrlen); | |
1132 | if (newsock < 0) { | |
1133 | error("accept: %.100s", strerror(errno)); | |
1134 | return; | |
1135 | } | |
1136 | nc = channel_new(rtype, | |
1137 | nextstate, newsock, newsock, -1, | |
1138 | c->local_window_max, c->local_maxpacket, | |
1139 | 0, xstrdup(rtype), 1); | |
1140 | if (nc == NULL) { | |
1141 | error("channel_post_port_listener: no new channel:"); | |
1142 | close(newsock); | |
1143 | return; | |
1144 | } | |
1145 | nc->listening_port = c->listening_port; | |
1146 | nc->host_port = c->host_port; | |
1147 | strlcpy(nc->path, c->path, sizeof(nc->path)); | |
1148 | ||
1149 | if (nextstate == SSH_CHANNEL_DYNAMIC) { | |
1150 | /* | |
1151 | * do not call the channel_post handler until | |
1152 | * this flag has been reset by a pre-handler. | |
1153 | * otherwise the FD_ISSET calls might overflow | |
1154 | */ | |
1155 | nc->delayed = 1; | |
1156 | } else { | |
1157 | port_open_helper(nc, rtype); | |
1158 | } | |
1159 | } | |
1160 | } | |
1161 | ||
1162 | /* | |
1163 | * This is the authentication agent socket listening for connections from | |
1164 | * clients. | |
1165 | */ | |
1166 | static void | |
1167 | channel_post_auth_listener(Channel *c, fd_set * readset, fd_set * writeset) | |
1168 | { | |
1169 | Channel *nc; | |
1170 | char *name; | |
1171 | int newsock; | |
1172 | struct sockaddr addr; | |
1173 | socklen_t addrlen; | |
1174 | ||
1175 | if (FD_ISSET(c->sock, readset)) { | |
1176 | addrlen = sizeof(addr); | |
1177 | newsock = accept(c->sock, &addr, &addrlen); | |
1178 | if (newsock < 0) { | |
1179 | error("accept from auth socket: %.100s", strerror(errno)); | |
1180 | return; | |
1181 | } | |
1182 | name = xstrdup("accepted auth socket"); | |
1183 | nc = channel_new("accepted auth socket", | |
1184 | SSH_CHANNEL_OPENING, newsock, newsock, -1, | |
1185 | c->local_window_max, c->local_maxpacket, | |
1186 | 0, name, 1); | |
1187 | if (nc == NULL) { | |
1188 | error("channel_post_auth_listener: channel_new failed"); | |
1189 | xfree(name); | |
1190 | close(newsock); | |
1191 | } | |
1192 | if (compat20) { | |
1193 | packet_start(SSH2_MSG_CHANNEL_OPEN); | |
1194 | packet_put_cstring("auth-agent@openssh.com"); | |
1195 | packet_put_int(nc->self); | |
1196 | packet_put_int(c->local_window_max); | |
1197 | packet_put_int(c->local_maxpacket); | |
1198 | } else { | |
1199 | packet_start(SSH_SMSG_AGENT_OPEN); | |
1200 | packet_put_int(nc->self); | |
1201 | } | |
1202 | packet_send(); | |
1203 | } | |
1204 | } | |
1205 | ||
1206 | static void | |
1207 | channel_post_connecting(Channel *c, fd_set * readset, fd_set * writeset) | |
1208 | { | |
1209 | int err = 0; | |
1210 | socklen_t sz = sizeof(err); | |
1211 | ||
1212 | if (FD_ISSET(c->sock, writeset)) { | |
1213 | if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, (char *)&err, | |
1214 | &sz) < 0) { | |
1215 | err = errno; | |
1216 | error("getsockopt SO_ERROR failed"); | |
1217 | } | |
1218 | if (err == 0) { | |
1219 | debug("channel %d: connected", c->self); | |
1220 | c->type = SSH_CHANNEL_OPEN; | |
1221 | if (compat20) { | |
1222 | packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION); | |
1223 | packet_put_int(c->remote_id); | |
1224 | packet_put_int(c->self); | |
1225 | packet_put_int(c->local_window); | |
1226 | packet_put_int(c->local_maxpacket); | |
1227 | } else { | |
1228 | packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION); | |
1229 | packet_put_int(c->remote_id); | |
1230 | packet_put_int(c->self); | |
1231 | } | |
1232 | } else { | |
1233 | debug("channel %d: not connected: %s", | |
1234 | c->self, strerror(err)); | |
1235 | if (compat20) { | |
1236 | packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE); | |
1237 | packet_put_int(c->remote_id); | |
1238 | packet_put_int(SSH2_OPEN_CONNECT_FAILED); | |
1239 | if (!(datafellows & SSH_BUG_OPENFAILURE)) { | |
1240 | packet_put_cstring(strerror(err)); | |
1241 | packet_put_cstring(""); | |
1242 | } | |
1243 | } else { | |
1244 | packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); | |
1245 | packet_put_int(c->remote_id); | |
1246 | } | |
1247 | chan_mark_dead(c); | |
1248 | } | |
1249 | packet_send(); | |
1250 | } | |
1251 | } | |
1252 | ||
1253 | static int | |
1254 | channel_handle_rfd(Channel *c, fd_set * readset, fd_set * writeset) | |
1255 | { | |
1256 | char buf[16*1024]; | |
1257 | int len; | |
1258 | ||
1259 | if (c->rfd != -1 && | |
1260 | FD_ISSET(c->rfd, readset)) { | |
1261 | len = read(c->rfd, buf, sizeof(buf)); | |
1262 | if (len < 0 && (errno == EINTR || errno == EAGAIN)) | |
1263 | return 1; | |
1264 | if (len <= 0) { | |
1265 | debug("channel %d: read<=0 rfd %d len %d", | |
1266 | c->self, c->rfd, len); | |
1267 | if (c->type != SSH_CHANNEL_OPEN) { | |
1268 | debug("channel %d: not open", c->self); | |
1269 | chan_mark_dead(c); | |
1270 | return -1; | |
1271 | } else if (compat13) { | |
1272 | buffer_consume(&c->output, buffer_len(&c->output)); | |
1273 | c->type = SSH_CHANNEL_INPUT_DRAINING; | |
1274 | debug("channel %d: input draining.", c->self); | |
1275 | } else { | |
1276 | chan_read_failed(c); | |
1277 | } | |
1278 | return -1; | |
1279 | } | |
1280 | if(c->input_filter != NULL) { | |
1281 | if (c->input_filter(c, buf, len) == -1) { | |
1282 | debug("channel %d: filter stops", c->self); | |
1283 | chan_read_failed(c); | |
1284 | } | |
1285 | } else { | |
1286 | buffer_append(&c->input, buf, len); | |
1287 | } | |
1288 | } | |
1289 | return 1; | |
1290 | } | |
1291 | static int | |
1292 | channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset) | |
1293 | { | |
1294 | struct termios tio; | |
1295 | u_char *data; | |
1296 | u_int dlen; | |
1297 | int len; | |
1298 | ||
1299 | /* Send buffered output data to the socket. */ | |
1300 | if (c->wfd != -1 && | |
1301 | FD_ISSET(c->wfd, writeset) && | |
1302 | buffer_len(&c->output) > 0) { | |
1303 | data = buffer_ptr(&c->output); | |
1304 | dlen = buffer_len(&c->output); | |
1305 | len = write(c->wfd, data, dlen); | |
1306 | if (len < 0 && (errno == EINTR || errno == EAGAIN)) | |
1307 | return 1; | |
1308 | if (len <= 0) { | |
1309 | if (c->type != SSH_CHANNEL_OPEN) { | |
1310 | debug("channel %d: not open", c->self); | |
1311 | chan_mark_dead(c); | |
1312 | return -1; | |
1313 | } else if (compat13) { | |
1314 | buffer_consume(&c->output, buffer_len(&c->output)); | |
1315 | debug("channel %d: input draining.", c->self); | |
1316 | c->type = SSH_CHANNEL_INPUT_DRAINING; | |
1317 | } else { | |
1318 | chan_write_failed(c); | |
1319 | } | |
1320 | return -1; | |
1321 | } | |
1322 | if (compat20 && c->isatty && dlen >= 1 && data[0] != '\r') { | |
1323 | if (tcgetattr(c->wfd, &tio) == 0 && | |
1324 | !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) { | |
1325 | /* | |
1326 | * Simulate echo to reduce the impact of | |
1327 | * traffic analysis. We need to match the | |
1328 | * size of a SSH2_MSG_CHANNEL_DATA message | |
1329 | * (4 byte channel id + data) | |
1330 | */ | |
1331 | packet_send_ignore(4 + len); | |
1332 | packet_send(); | |
1333 | } | |
1334 | } | |
1335 | buffer_consume(&c->output, len); | |
1336 | if (compat20 && len > 0) { | |
1337 | c->local_consumed += len; | |
1338 | } | |
1339 | } | |
1340 | return 1; | |
1341 | } | |
1342 | static int | |
1343 | channel_handle_efd(Channel *c, fd_set * readset, fd_set * writeset) | |
1344 | { | |
1345 | char buf[16*1024]; | |
1346 | int len; | |
1347 | ||
1348 | /** XXX handle drain efd, too */ | |
1349 | if (c->efd != -1) { | |
1350 | if (c->extended_usage == CHAN_EXTENDED_WRITE && | |
1351 | FD_ISSET(c->efd, writeset) && | |
1352 | buffer_len(&c->extended) > 0) { | |
1353 | len = write(c->efd, buffer_ptr(&c->extended), | |
1354 | buffer_len(&c->extended)); | |
1355 | debug2("channel %d: written %d to efd %d", | |
1356 | c->self, len, c->efd); | |
1357 | if (len < 0 && (errno == EINTR || errno == EAGAIN)) | |
1358 | return 1; | |
1359 | if (len <= 0) { | |
1360 | debug2("channel %d: closing write-efd %d", | |
1361 | c->self, c->efd); | |
1362 | channel_close_fd(&c->efd); | |
1363 | } else { | |
1364 | buffer_consume(&c->extended, len); | |
1365 | c->local_consumed += len; | |
1366 | } | |
1367 | } else if (c->extended_usage == CHAN_EXTENDED_READ && | |
1368 | FD_ISSET(c->efd, readset)) { | |
1369 | len = read(c->efd, buf, sizeof(buf)); | |
1370 | debug2("channel %d: read %d from efd %d", | |
1371 | c->self, len, c->efd); | |
1372 | if (len < 0 && (errno == EINTR || errno == EAGAIN)) | |
1373 | return 1; | |
1374 | if (len <= 0) { | |
1375 | debug2("channel %d: closing read-efd %d", | |
1376 | c->self, c->efd); | |
1377 | channel_close_fd(&c->efd); | |
1378 | } else { | |
1379 | buffer_append(&c->extended, buf, len); | |
1380 | } | |
1381 | } | |
1382 | } | |
1383 | return 1; | |
1384 | } | |
1385 | static int | |
1386 | channel_check_window(Channel *c) | |
1387 | { | |
1388 | if (c->type == SSH_CHANNEL_OPEN && | |
1389 | !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) && | |
1390 | c->local_window < c->local_window_max/2 && | |
1391 | c->local_consumed > 0) { | |
1392 | packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST); | |
1393 | packet_put_int(c->remote_id); | |
1394 | packet_put_int(c->local_consumed); | |
1395 | packet_send(); | |
1396 | debug2("channel %d: window %d sent adjust %d", | |
1397 | c->self, c->local_window, | |
1398 | c->local_consumed); | |
1399 | c->local_window += c->local_consumed; | |
1400 | c->local_consumed = 0; | |
1401 | } | |
1402 | return 1; | |
1403 | } | |
1404 | ||
1405 | static void | |
1406 | channel_post_open_1(Channel *c, fd_set * readset, fd_set * writeset) | |
1407 | { | |
1408 | if (c->delayed) | |
1409 | return; | |
1410 | channel_handle_rfd(c, readset, writeset); | |
1411 | channel_handle_wfd(c, readset, writeset); | |
1412 | } | |
1413 | ||
1414 | static void | |
1415 | channel_post_open_2(Channel *c, fd_set * readset, fd_set * writeset) | |
1416 | { | |
1417 | if (c->delayed) | |
1418 | return; | |
1419 | channel_handle_rfd(c, readset, writeset); | |
1420 | channel_handle_wfd(c, readset, writeset); | |
1421 | channel_handle_efd(c, readset, writeset); | |
1422 | ||
1423 | channel_check_window(c); | |
1424 | } | |
1425 | ||
1426 | static void | |
1427 | channel_post_output_drain_13(Channel *c, fd_set * readset, fd_set * writeset) | |
1428 | { | |
1429 | int len; | |
1430 | /* Send buffered output data to the socket. */ | |
1431 | if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) { | |
1432 | len = write(c->sock, buffer_ptr(&c->output), | |
1433 | buffer_len(&c->output)); | |
1434 | if (len <= 0) | |
1435 | buffer_consume(&c->output, buffer_len(&c->output)); | |
1436 | else | |
1437 | buffer_consume(&c->output, len); | |
1438 | } | |
1439 | } | |
1440 | ||
1441 | static void | |
1442 | channel_handler_init_20(void) | |
1443 | { | |
1444 | channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_20; | |
1445 | channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; | |
1446 | channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; | |
1447 | channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener; | |
1448 | channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; | |
1449 | channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; | |
1450 | channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; | |
1451 | channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; | |
1452 | ||
1453 | channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_2; | |
1454 | channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; | |
1455 | channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener; | |
1456 | channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; | |
1457 | channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; | |
1458 | channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; | |
1459 | channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open_2; | |
1460 | } | |
1461 | ||
1462 | static void | |
1463 | channel_handler_init_13(void) | |
1464 | { | |
1465 | channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13; | |
1466 | channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13; | |
1467 | channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; | |
1468 | channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; | |
1469 | channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; | |
1470 | channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining; | |
1471 | channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining; | |
1472 | channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; | |
1473 | channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; | |
1474 | ||
1475 | channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_1; | |
1476 | channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; | |
1477 | channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; | |
1478 | channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; | |
1479 | channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13; | |
1480 | channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; | |
1481 | channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open_1; | |
1482 | } | |
1483 | ||
1484 | static void | |
1485 | channel_handler_init_15(void) | |
1486 | { | |
1487 | channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_15; | |
1488 | channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; | |
1489 | channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; | |
1490 | channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; | |
1491 | channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; | |
1492 | channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; | |
1493 | channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; | |
1494 | ||
1495 | channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; | |
1496 | channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; | |
1497 | channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; | |
1498 | channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_1; | |
1499 | channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; | |
1500 | channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open_1; | |
1501 | } | |
1502 | ||
1503 | static void | |
1504 | channel_handler_init(void) | |
1505 | { | |
1506 | int i; | |
1507 | for(i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) { | |
1508 | channel_pre[i] = NULL; | |
1509 | channel_post[i] = NULL; | |
1510 | } | |
1511 | if (compat20) | |
1512 | channel_handler_init_20(); | |
1513 | else if (compat13) | |
1514 | channel_handler_init_13(); | |
1515 | else | |
1516 | channel_handler_init_15(); | |
1517 | } | |
1518 | ||
1519 | /* gc dead channels */ | |
1520 | static void | |
1521 | channel_garbage_collect(Channel *c) | |
1522 | { | |
1523 | if (c == NULL) | |
1524 | return; | |
1525 | if (c->detach_user != NULL) { | |
1526 | if (!chan_is_dead(c, 0)) | |
1527 | return; | |
1528 | debug("channel %d: gc: notify user", c->self); | |
1529 | c->detach_user(c->self, NULL); | |
1530 | /* if we still have a callback */ | |
1531 | if (c->detach_user != NULL) | |
1532 | return; | |
1533 | debug("channel %d: gc: user detached", c->self); | |
1534 | } | |
1535 | if (!chan_is_dead(c, 1)) | |
1536 | return; | |
1537 | debug("channel %d: garbage collecting", c->self); | |
1538 | channel_free(c); | |
1539 | } | |
1540 | ||
1541 | static void | |
1542 | channel_handler(chan_fn *ftab[], fd_set * readset, fd_set * writeset) | |
1543 | { | |
1544 | static int did_init = 0; | |
1545 | int i; | |
1546 | Channel *c; | |
1547 | ||
1548 | if (!did_init) { | |
1549 | channel_handler_init(); | |
1550 | did_init = 1; | |
1551 | } | |
1552 | for (i = 0; i < channels_alloc; i++) { | |
1553 | c = channels[i]; | |
1554 | if (c == NULL) | |
1555 | continue; | |
1556 | if (ftab[c->type] != NULL) | |
1557 | (*ftab[c->type])(c, readset, writeset); | |
1558 | channel_garbage_collect(c); | |
1559 | } | |
1560 | } | |
1561 | ||
1562 | /* | |
1563 | * Allocate/update select bitmasks and add any bits relevant to channels in | |
1564 | * select bitmasks. | |
1565 | */ | |
1566 | void | |
1567 | channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp, | |
1568 | int *nallocp, int rekeying) | |
1569 | { | |
1570 | int n; | |
1571 | u_int sz; | |
1572 | ||
1573 | n = MAX(*maxfdp, channel_max_fd); | |
1574 | ||
1575 | sz = howmany(n+1, NFDBITS) * sizeof(fd_mask); | |
1576 | /* perhaps check sz < nalloc/2 and shrink? */ | |
1577 | if (*readsetp == NULL || sz > *nallocp) { | |
1578 | *readsetp = xrealloc(*readsetp, sz); | |
1579 | *writesetp = xrealloc(*writesetp, sz); | |
1580 | *nallocp = sz; | |
1581 | } | |
1582 | *maxfdp = n; | |
1583 | memset(*readsetp, 0, sz); | |
1584 | memset(*writesetp, 0, sz); | |
1585 | ||
1586 | if (!rekeying) | |
1587 | channel_handler(channel_pre, *readsetp, *writesetp); | |
1588 | } | |
1589 | ||
1590 | /* | |
1591 | * After select, perform any appropriate operations for channels which have | |
1592 | * events pending. | |
1593 | */ | |
1594 | void | |
1595 | channel_after_select(fd_set * readset, fd_set * writeset) | |
1596 | { | |
1597 | channel_handler(channel_post, readset, writeset); | |
1598 | } | |
1599 | ||
1600 | ||
1601 | /* If there is data to send to the connection, enqueue some of it now. */ | |
1602 | ||
1603 | void | |
1604 | channel_output_poll() | |
1605 | { | |
1606 | int len, i; | |
1607 | Channel *c; | |
1608 | ||
1609 | for (i = 0; i < channels_alloc; i++) { | |
1610 | c = channels[i]; | |
1611 | if (c == NULL) | |
1612 | continue; | |
1613 | ||
1614 | /* | |
1615 | * We are only interested in channels that can have buffered | |
1616 | * incoming data. | |
1617 | */ | |
1618 | if (compat13) { | |
1619 | if (c->type != SSH_CHANNEL_OPEN && | |
1620 | c->type != SSH_CHANNEL_INPUT_DRAINING) | |
1621 | continue; | |
1622 | } else { | |
1623 | if (c->type != SSH_CHANNEL_OPEN) | |
1624 | continue; | |
1625 | } | |
1626 | if (compat20 && | |
1627 | (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) { | |
1628 | /* XXX is this true? */ | |
1629 | debug3("channel %d: will not send data after close", c->self); | |
1630 | continue; | |
1631 | } | |
1632 | ||
1633 | /* Get the amount of buffered data for this channel. */ | |
1634 | if ((c->istate == CHAN_INPUT_OPEN || | |
1635 | c->istate == CHAN_INPUT_WAIT_DRAIN) && | |
1636 | (len = buffer_len(&c->input)) > 0) { | |
1637 | /* | |
1638 | * Send some data for the other side over the secure | |
1639 | * connection. | |
1640 | */ | |
1641 | if (compat20) { | |
1642 | if (len > c->remote_window) | |
1643 | len = c->remote_window; | |
1644 | if (len > c->remote_maxpacket) | |
1645 | len = c->remote_maxpacket; | |
1646 | } else { | |
1647 | if (packet_is_interactive()) { | |
1648 | if (len > 1024) | |
1649 | len = 512; | |
1650 | } else { | |
1651 | /* Keep the packets at reasonable size. */ | |
1652 | if (len > packet_get_maxsize()/2) | |
1653 | len = packet_get_maxsize()/2; | |
1654 | } | |
1655 | } | |
1656 | if (len > 0) { | |
1657 | packet_start(compat20 ? | |
1658 | SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA); | |
1659 | packet_put_int(c->remote_id); | |
1660 | packet_put_string(buffer_ptr(&c->input), len); | |
1661 | packet_send(); | |
1662 | buffer_consume(&c->input, len); | |
1663 | c->remote_window -= len; | |
1664 | } | |
1665 | } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) { | |
1666 | if (compat13) | |
1667 | fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3"); | |
1668 | /* | |
1669 | * input-buffer is empty and read-socket shutdown: | |
1670 | * tell peer, that we will not send more data: send IEOF | |
1671 | */ | |
1672 | chan_ibuf_empty(c); | |
1673 | } | |
1674 | /* Send extended data, i.e. stderr */ | |
1675 | if (compat20 && | |
1676 | c->remote_window > 0 && | |
1677 | (len = buffer_len(&c->extended)) > 0 && | |
1678 | c->extended_usage == CHAN_EXTENDED_READ) { | |
1679 | debug2("channel %d: rwin %d elen %d euse %d", | |
1680 | c->self, c->remote_window, buffer_len(&c->extended), | |
1681 | c->extended_usage); | |
1682 | if (len > c->remote_window) | |
1683 | len = c->remote_window; | |
1684 | if (len > c->remote_maxpacket) | |
1685 | len = c->remote_maxpacket; | |
1686 | packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA); | |
1687 | packet_put_int(c->remote_id); | |
1688 | packet_put_int(SSH2_EXTENDED_DATA_STDERR); | |
1689 | packet_put_string(buffer_ptr(&c->extended), len); | |
1690 | packet_send(); | |
1691 | buffer_consume(&c->extended, len); | |
1692 | c->remote_window -= len; | |
1693 | debug2("channel %d: sent ext data %d", c->self, len); | |
1694 | } | |
1695 | } | |
1696 | } | |
1697 | ||
1698 | ||
1699 | /* -- protocol input */ | |
1700 | ||
1701 | void | |
1702 | channel_input_data(int type, int plen, void *ctxt) | |
1703 | { | |
1704 | int id; | |
1705 | char *data; | |
1706 | u_int data_len; | |
1707 | Channel *c; | |
1708 | ||
1709 | /* Get the channel number and verify it. */ | |
1710 | id = packet_get_int(); | |
1711 | c = channel_lookup(id); | |
1712 | if (c == NULL) | |
1713 | packet_disconnect("Received data for nonexistent channel %d.", id); | |
1714 | ||
1715 | /* Ignore any data for non-open channels (might happen on close) */ | |
1716 | if (c->type != SSH_CHANNEL_OPEN && | |
1717 | c->type != SSH_CHANNEL_X11_OPEN) | |
1718 | return; | |
1719 | ||
1720 | /* same for protocol 1.5 if output end is no longer open */ | |
1721 | if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) | |
1722 | return; | |
1723 | ||
1724 | /* Get the data. */ | |
1725 | data = packet_get_string(&data_len); | |
1726 | packet_done(); | |
1727 | ||
1728 | if (compat20){ | |
1729 | if (data_len > c->local_maxpacket) { | |
1730 | log("channel %d: rcvd big packet %d, maxpack %d", | |
1731 | c->self, data_len, c->local_maxpacket); | |
1732 | } | |
1733 | if (data_len > c->local_window) { | |
1734 | log("channel %d: rcvd too much data %d, win %d", | |
1735 | c->self, data_len, c->local_window); | |
1736 | xfree(data); | |
1737 | return; | |
1738 | } | |
1739 | c->local_window -= data_len; | |
1740 | }else{ | |
1741 | packet_integrity_check(plen, 4 + 4 + data_len, type); | |
1742 | } | |
1743 | buffer_append(&c->output, data, data_len); | |
1744 | xfree(data); | |
1745 | } | |
1746 | ||
1747 | void | |
1748 | channel_input_extended_data(int type, int plen, void *ctxt) | |
1749 | { | |
1750 | int id; | |
1751 | int tcode; | |
1752 | char *data; | |
1753 | u_int data_len; | |
1754 | Channel *c; | |
1755 | ||
1756 | /* Get the channel number and verify it. */ | |
1757 | id = packet_get_int(); | |
1758 | c = channel_lookup(id); | |
1759 | ||
1760 | if (c == NULL) | |
1761 | packet_disconnect("Received extended_data for bad channel %d.", id); | |
1762 | if (c->type != SSH_CHANNEL_OPEN) { | |
1763 | log("channel %d: ext data for non open", id); | |
1764 | return; | |
1765 | } | |
1766 | tcode = packet_get_int(); | |
1767 | if (c->efd == -1 || | |
1768 | c->extended_usage != CHAN_EXTENDED_WRITE || | |
1769 | tcode != SSH2_EXTENDED_DATA_STDERR) { | |
1770 | log("channel %d: bad ext data", c->self); | |
1771 | return; | |
1772 | } | |
1773 | data = packet_get_string(&data_len); | |
1774 | packet_done(); | |
1775 | if (data_len > c->local_window) { | |
1776 | log("channel %d: rcvd too much extended_data %d, win %d", | |
1777 | c->self, data_len, c->local_window); | |
1778 | xfree(data); | |
1779 | return; | |
1780 | } | |
1781 | debug2("channel %d: rcvd ext data %d", c->self, data_len); | |
1782 | c->local_window -= data_len; | |
1783 | buffer_append(&c->extended, data, data_len); | |
1784 | xfree(data); | |
1785 | } | |
1786 | ||
1787 | void | |
1788 | channel_input_ieof(int type, int plen, void *ctxt) | |
1789 | { | |
1790 | int id; | |
1791 | Channel *c; | |
1792 | ||
1793 | packet_integrity_check(plen, 4, type); | |
1794 | ||
1795 | id = packet_get_int(); | |
1796 | c = channel_lookup(id); | |
1797 | if (c == NULL) | |
1798 | packet_disconnect("Received ieof for nonexistent channel %d.", id); | |
1799 | chan_rcvd_ieof(c); | |
1800 | ||
1801 | /* XXX force input close */ | |
1802 | if (c->force_drain) { | |
1803 | debug("channel %d: FORCE input drain", c->self); | |
1804 | c->istate = CHAN_INPUT_WAIT_DRAIN; | |
1805 | } | |
1806 | ||
1807 | } | |
1808 | ||
1809 | void | |
1810 | channel_input_close(int type, int plen, void *ctxt) | |
1811 | { | |
1812 | int id; | |
1813 | Channel *c; | |
1814 | ||
1815 | packet_integrity_check(plen, 4, type); | |
1816 | ||
1817 | id = packet_get_int(); | |
1818 | c = channel_lookup(id); | |
1819 | if (c == NULL) | |
1820 | packet_disconnect("Received close for nonexistent channel %d.", id); | |
1821 | ||
1822 | /* | |
1823 | * Send a confirmation that we have closed the channel and no more | |
1824 | * data is coming for it. | |
1825 | */ | |
1826 | packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION); | |
1827 | packet_put_int(c->remote_id); | |
1828 | packet_send(); | |
1829 | ||
1830 | /* | |
1831 | * If the channel is in closed state, we have sent a close request, | |
1832 | * and the other side will eventually respond with a confirmation. | |
1833 | * Thus, we cannot free the channel here, because then there would be | |
1834 | * no-one to receive the confirmation. The channel gets freed when | |
1835 | * the confirmation arrives. | |
1836 | */ | |
1837 | if (c->type != SSH_CHANNEL_CLOSED) { | |
1838 | /* | |
1839 | * Not a closed channel - mark it as draining, which will | |
1840 | * cause it to be freed later. | |
1841 | */ | |
1842 | buffer_consume(&c->input, buffer_len(&c->input)); | |
1843 | c->type = SSH_CHANNEL_OUTPUT_DRAINING; | |
1844 | } | |
1845 | } | |
1846 | ||
1847 | /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */ | |
1848 | void | |
1849 | channel_input_oclose(int type, int plen, void *ctxt) | |
1850 | { | |
1851 | int id = packet_get_int(); | |
1852 | Channel *c = channel_lookup(id); | |
1853 | packet_integrity_check(plen, 4, type); | |
1854 | if (c == NULL) | |
1855 | packet_disconnect("Received oclose for nonexistent channel %d.", id); | |
1856 | chan_rcvd_oclose(c); | |
1857 | } | |
1858 | ||
1859 | void | |
1860 | channel_input_close_confirmation(int type, int plen, void *ctxt) | |
1861 | { | |
1862 | int id = packet_get_int(); | |
1863 | Channel *c = channel_lookup(id); | |
1864 | ||
1865 | packet_done(); | |
1866 | if (c == NULL) | |
1867 | packet_disconnect("Received close confirmation for " | |
1868 | "out-of-range channel %d.", id); | |
1869 | if (c->type != SSH_CHANNEL_CLOSED) | |
1870 | packet_disconnect("Received close confirmation for " | |
1871 | "non-closed channel %d (type %d).", id, c->type); | |
1872 | channel_free(c); | |
1873 | } | |
1874 | ||
1875 | void | |
1876 | channel_input_open_confirmation(int type, int plen, void *ctxt) | |
1877 | { | |
1878 | int id, remote_id; | |
1879 | Channel *c; | |
1880 | ||
1881 | if (!compat20) | |
1882 | packet_integrity_check(plen, 4 + 4, type); | |
1883 | ||
1884 | id = packet_get_int(); | |
1885 | c = channel_lookup(id); | |
1886 | ||
1887 | if (c==NULL || c->type != SSH_CHANNEL_OPENING) | |
1888 | packet_disconnect("Received open confirmation for " | |
1889 | "non-opening channel %d.", id); | |
1890 | remote_id = packet_get_int(); | |
1891 | /* Record the remote channel number and mark that the channel is now open. */ | |
1892 | c->remote_id = remote_id; | |
1893 | c->type = SSH_CHANNEL_OPEN; | |
1894 | ||
1895 | if (compat20) { | |
1896 | c->remote_window = packet_get_int(); | |
1897 | c->remote_maxpacket = packet_get_int(); | |
1898 | packet_done(); | |
1899 | if (c->cb_fn != NULL && c->cb_event == type) { | |
1900 | debug2("callback start"); | |
1901 | c->cb_fn(c->self, c->cb_arg); | |
1902 | debug2("callback done"); | |
1903 | } | |
1904 | debug("channel %d: open confirm rwindow %d rmax %d", c->self, | |
1905 | c->remote_window, c->remote_maxpacket); | |
1906 | } | |
1907 | } | |
1908 | ||
1909 | static char * | |
1910 | reason2txt(int reason) | |
1911 | { | |
1912 | switch(reason) { | |
1913 | case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED: | |
1914 | return "administratively prohibited"; | |
1915 | case SSH2_OPEN_CONNECT_FAILED: | |
1916 | return "connect failed"; | |
1917 | case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE: | |
1918 | return "unknown channel type"; | |
1919 | case SSH2_OPEN_RESOURCE_SHORTAGE: | |
1920 | return "resource shortage"; | |
1921 | } | |
1922 | return "unknown reason"; | |
1923 | } | |
1924 | ||
1925 | void | |
1926 | channel_input_open_failure(int type, int plen, void *ctxt) | |
1927 | { | |
1928 | int id, reason; | |
1929 | char *msg = NULL, *lang = NULL; | |
1930 | Channel *c; | |
1931 | ||
1932 | if (!compat20) | |
1933 | packet_integrity_check(plen, 4, type); | |
1934 | ||
1935 | id = packet_get_int(); | |
1936 | c = channel_lookup(id); | |
1937 | ||
1938 | if (c==NULL || c->type != SSH_CHANNEL_OPENING) | |
1939 | packet_disconnect("Received open failure for " | |
1940 | "non-opening channel %d.", id); | |
1941 | if (compat20) { | |
1942 | reason = packet_get_int(); | |
1943 | if (!(datafellows & SSH_BUG_OPENFAILURE)) { | |
1944 | msg = packet_get_string(NULL); | |
1945 | lang = packet_get_string(NULL); | |
1946 | } | |
1947 | packet_done(); | |
1948 | log("channel %d: open failed: %s%s%s", id, | |
1949 | reason2txt(reason), msg ? ": ": "", msg ? msg : ""); | |
1950 | if (msg != NULL) | |
1951 | xfree(msg); | |
1952 | if (lang != NULL) | |
1953 | xfree(lang); | |
1954 | } | |
1955 | /* Free the channel. This will also close the socket. */ | |
1956 | channel_free(c); | |
1957 | } | |
1958 | ||
1959 | void | |
1960 | channel_input_channel_request(int type, int plen, void *ctxt) | |
1961 | { | |
1962 | int id; | |
1963 | Channel *c; | |
1964 | ||
1965 | id = packet_get_int(); | |
1966 | c = channel_lookup(id); | |
1967 | ||
1968 | if (c == NULL || | |
1969 | (c->type != SSH_CHANNEL_OPEN && c->type != SSH_CHANNEL_LARVAL)) | |
1970 | packet_disconnect("Received request for " | |
1971 | "non-open channel %d.", id); | |
1972 | if (c->cb_fn != NULL && c->cb_event == type) { | |
1973 | debug2("callback start"); | |
1974 | c->cb_fn(c->self, c->cb_arg); | |
1975 | debug2("callback done"); | |
1976 | } else { | |
1977 | char *service = packet_get_string(NULL); | |
1978 | debug("channel %d: rcvd request for %s", c->self, service); | |
1979 | debug("cb_fn %p cb_event %d", c->cb_fn , c->cb_event); | |
1980 | xfree(service); | |
1981 | } | |
1982 | } | |
1983 | ||
1984 | void | |
1985 | channel_input_window_adjust(int type, int plen, void *ctxt) | |
1986 | { | |
1987 | Channel *c; | |
1988 | int id, adjust; | |
1989 | ||
1990 | if (!compat20) | |
1991 | return; | |
1992 | ||
1993 | /* Get the channel number and verify it. */ | |
1994 | id = packet_get_int(); | |
1995 | c = channel_lookup(id); | |
1996 | ||
1997 | if (c == NULL || c->type != SSH_CHANNEL_OPEN) { | |
1998 | log("Received window adjust for " | |
1999 | "non-open channel %d.", id); | |
2000 | return; | |
2001 | } | |
2002 | adjust = packet_get_int(); | |
2003 | packet_done(); | |
2004 | debug2("channel %d: rcvd adjust %d", id, adjust); | |
2005 | c->remote_window += adjust; | |
2006 | } | |
2007 | ||
2008 | void | |
2009 | channel_input_port_open(int type, int plen, void *ctxt) | |
2010 | { | |
2011 | Channel *c = NULL; | |
2012 | u_short host_port; | |
2013 | char *host, *originator_string; | |
2014 | int remote_id, sock = -1; | |
2015 | ||
2016 | remote_id = packet_get_int(); | |
2017 | host = packet_get_string(NULL); | |
2018 | host_port = packet_get_int(); | |
2019 | ||
2020 | if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) { | |
2021 | originator_string = packet_get_string(NULL); | |
2022 | } else { | |
2023 | originator_string = xstrdup("unknown (remote did not supply name)"); | |
2024 | } | |
2025 | packet_done(); | |
2026 | sock = channel_connect_to(host, host_port); | |
2027 | if (sock != -1) { | |
2028 | c = channel_new("connected socket", | |
2029 | SSH_CHANNEL_CONNECTING, sock, sock, -1, 0, 0, 0, | |
2030 | originator_string, 1); | |
2031 | if (c == NULL) { | |
2032 | error("channel_input_port_open: channel_new failed"); | |
2033 | close(sock); | |
2034 | } else { | |
2035 | c->remote_id = remote_id; | |
2036 | } | |
2037 | } | |
2038 | if (c == NULL) { | |
2039 | packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); | |
2040 | packet_put_int(remote_id); | |
2041 | packet_send(); | |
2042 | } | |
2043 | xfree(host); | |
2044 | } | |
2045 | ||
2046 | ||
2047 | /* -- tcp forwarding */ | |
2048 | ||
2049 | void | |
2050 | channel_set_af(int af) | |
2051 | { | |
2052 | IPv4or6 = af; | |
2053 | } | |
2054 | ||
2055 | /* | |
2056 | * Initiate forwarding of connections to local port "port" through the secure | |
2057 | * channel to host:port from remote side. | |
2058 | */ | |
2059 | int | |
2060 | channel_request_local_forwarding(u_short listen_port, const char *host_to_connect, | |
2061 | u_short port_to_connect, int gateway_ports) | |
2062 | { | |
2063 | return channel_request_forwarding( | |
2064 | NULL, listen_port, | |
2065 | host_to_connect, port_to_connect, | |
2066 | gateway_ports, /*remote_fwd*/ 0); | |
2067 | } | |
2068 | ||
2069 | /* | |
2070 | * If 'remote_fwd' is true we have a '-R style' listener for protocol 2 | |
2071 | * (SSH_CHANNEL_RPORT_LISTENER). | |
2072 | */ | |
2073 | int | |
2074 | channel_request_forwarding( | |
2075 | const char *listen_address, u_short listen_port, | |
2076 | const char *host_to_connect, u_short port_to_connect, | |
2077 | int gateway_ports, int remote_fwd) | |
2078 | { | |
2079 | Channel *c; | |
2080 | int success, sock, on = 1, type; | |
2081 | struct addrinfo hints, *ai, *aitop; | |
2082 | char ntop[NI_MAXHOST], strport[NI_MAXSERV]; | |
2083 | const char *host; | |
2084 | struct linger linger; | |
2085 | ||
2086 | success = 0; | |
2087 | ||
2088 | if (remote_fwd) { | |
2089 | host = listen_address; | |
2090 | type = SSH_CHANNEL_RPORT_LISTENER; | |
2091 | } else { | |
2092 | host = host_to_connect; | |
2093 | type = SSH_CHANNEL_PORT_LISTENER; | |
2094 | } | |
2095 | ||
2096 | if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) { | |
2097 | error("Forward host name too long."); | |
2098 | return success; | |
2099 | } | |
2100 | ||
2101 | /* XXX listen_address is currently ignored */ | |
2102 | /* | |
2103 | * getaddrinfo returns a loopback address if the hostname is | |
2104 | * set to NULL and hints.ai_flags is not AI_PASSIVE | |
2105 | */ | |
2106 | memset(&hints, 0, sizeof(hints)); | |
2107 | hints.ai_family = IPv4or6; | |
2108 | hints.ai_flags = gateway_ports ? AI_PASSIVE : 0; | |
2109 | hints.ai_socktype = SOCK_STREAM; | |
2110 | snprintf(strport, sizeof strport, "%d", listen_port); | |
2111 | if (getaddrinfo(NULL, strport, &hints, &aitop) != 0) | |
2112 | packet_disconnect("getaddrinfo: fatal error"); | |
2113 | ||
2114 | for (ai = aitop; ai; ai = ai->ai_next) { | |
2115 | if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) | |
2116 | continue; | |
2117 | if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), | |
2118 | strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) { | |
2119 | error("channel_request_forwarding: getnameinfo failed"); | |
2120 | continue; | |
2121 | } | |
2122 | /* Create a port to listen for the host. */ | |
2123 | sock = socket(ai->ai_family, SOCK_STREAM, 0); | |
2124 | if (sock < 0) { | |
2125 | /* this is no error since kernel may not support ipv6 */ | |
2126 | verbose("socket: %.100s", strerror(errno)); | |
2127 | continue; | |
2128 | } | |
2129 | /* | |
2130 | * Set socket options. We would like the socket to disappear | |
2131 | * as soon as it has been closed for whatever reason. | |
2132 | */ | |
2133 | setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on)); | |
2134 | linger.l_onoff = 1; | |
2135 | linger.l_linger = 5; | |
2136 | setsockopt(sock, SOL_SOCKET, SO_LINGER, (void *)&linger, sizeof(linger)); | |
2137 | debug("Local forwarding listening on %s port %s.", ntop, strport); | |
2138 | ||
2139 | /* Bind the socket to the address. */ | |
2140 | if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) { | |
2141 | /* address can be in use ipv6 address is already bound */ | |
2142 | if (!ai->ai_next) | |
2143 | error("bind: %.100s", strerror(errno)); | |
2144 | else | |
2145 | verbose("bind: %.100s", strerror(errno)); | |
2146 | ||
2147 | close(sock); | |
2148 | continue; | |
2149 | } | |
2150 | /* Start listening for connections on the socket. */ | |
2151 | if (listen(sock, 5) < 0) { | |
2152 | error("listen: %.100s", strerror(errno)); | |
2153 | close(sock); | |
2154 | continue; | |
2155 | } | |
2156 | /* Allocate a channel number for the socket. */ | |
2157 | c = channel_new("port listener", type, sock, sock, -1, | |
2158 | CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, | |
2159 | 0, xstrdup("port listener"), 1); | |
2160 | if (c == NULL) { | |
2161 | error("channel_request_forwarding: channel_new failed"); | |
2162 | close(sock); | |
2163 | continue; | |
2164 | } | |
2165 | strlcpy(c->path, host, sizeof(c->path)); | |
2166 | c->host_port = port_to_connect; | |
2167 | c->listening_port = listen_port; | |
2168 | success = 1; | |
2169 | } | |
2170 | if (success == 0) | |
2171 | error("channel_request_forwarding: cannot listen to port: %d", | |
2172 | listen_port); | |
2173 | freeaddrinfo(aitop); | |
2174 | return success; | |
2175 | } | |
2176 | ||
2177 | /* | |
2178 | * Initiate forwarding of connections to port "port" on remote host through | |
2179 | * the secure channel to host:port from local side. | |
2180 | */ | |
2181 | ||
2182 | void | |
2183 | channel_request_remote_forwarding(u_short listen_port, | |
2184 | const char *host_to_connect, u_short port_to_connect) | |
2185 | { | |
2186 | int payload_len, type, success = 0; | |
2187 | ||
2188 | /* Record locally that connection to this host/port is permitted. */ | |
2189 | if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION) | |
2190 | fatal("channel_request_remote_forwarding: too many forwards"); | |
2191 | ||
2192 | /* Send the forward request to the remote side. */ | |
2193 | if (compat20) { | |
2194 | const char *address_to_bind = "0.0.0.0"; | |
2195 | packet_start(SSH2_MSG_GLOBAL_REQUEST); | |
2196 | packet_put_cstring("tcpip-forward"); | |
2197 | packet_put_char(0); /* boolean: want reply */ | |
2198 | packet_put_cstring(address_to_bind); | |
2199 | packet_put_int(listen_port); | |
2200 | packet_send(); | |
2201 | packet_write_wait(); | |
2202 | /* Assume that server accepts the request */ | |
2203 | success = 1; | |
2204 | } else { | |
2205 | packet_start(SSH_CMSG_PORT_FORWARD_REQUEST); | |
2206 | packet_put_int(listen_port); | |
2207 | packet_put_cstring(host_to_connect); | |
2208 | packet_put_int(port_to_connect); | |
2209 | packet_send(); | |
2210 | packet_write_wait(); | |
2211 | ||
2212 | /* Wait for response from the remote side. */ | |
2213 | type = packet_read(&payload_len); | |
2214 | switch (type) { | |
2215 | case SSH_SMSG_SUCCESS: | |
2216 | success = 1; | |
2217 | break; | |
2218 | case SSH_SMSG_FAILURE: | |
2219 | log("Warning: Server denied remote port forwarding."); | |
2220 | break; | |
2221 | default: | |
2222 | /* Unknown packet */ | |
2223 | packet_disconnect("Protocol error for port forward request:" | |
2224 | "received packet type %d.", type); | |
2225 | } | |
2226 | } | |
2227 | if (success) { | |
2228 | permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect); | |
2229 | permitted_opens[num_permitted_opens].port_to_connect = port_to_connect; | |
2230 | permitted_opens[num_permitted_opens].listen_port = listen_port; | |
2231 | num_permitted_opens++; | |
2232 | } | |
2233 | } | |
2234 | ||
2235 | /* | |
2236 | * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates | |
2237 | * listening for the port, and sends back a success reply (or disconnect | |
2238 | * message if there was an error). This never returns if there was an error. | |
2239 | */ | |
2240 | ||
2241 | void | |
2242 | channel_input_port_forward_request(int is_root, int gateway_ports) | |
2243 | { | |
2244 | u_short port, host_port; | |
2245 | char *hostname; | |
2246 | ||
2247 | /* Get arguments from the packet. */ | |
2248 | port = packet_get_int(); | |
2249 | hostname = packet_get_string(NULL); | |
2250 | host_port = packet_get_int(); | |
2251 | ||
2252 | #ifndef HAVE_CYGWIN | |
2253 | /* | |
2254 | * Check that an unprivileged user is not trying to forward a | |
2255 | * privileged port. | |
2256 | */ | |
2257 | if (port < IPPORT_RESERVED && !is_root) | |
2258 | packet_disconnect("Requested forwarding of port %d but user is not root.", | |
2259 | port); | |
2260 | #endif | |
2261 | /* Initiate forwarding */ | |
2262 | channel_request_local_forwarding(port, hostname, host_port, gateway_ports); | |
2263 | ||
2264 | /* Free the argument string. */ | |
2265 | xfree(hostname); | |
2266 | } | |
2267 | ||
2268 | /* | |
2269 | * Permits opening to any host/port if permitted_opens[] is empty. This is | |
2270 | * usually called by the server, because the user could connect to any port | |
2271 | * anyway, and the server has no way to know but to trust the client anyway. | |
2272 | */ | |
2273 | void | |
2274 | channel_permit_all_opens() | |
2275 | { | |
2276 | if (num_permitted_opens == 0) | |
2277 | all_opens_permitted = 1; | |
2278 | } | |
2279 | ||
2280 | void | |
2281 | channel_add_permitted_opens(char *host, int port) | |
2282 | { | |
2283 | if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION) | |
2284 | fatal("channel_request_remote_forwarding: too many forwards"); | |
2285 | debug("allow port forwarding to host %s port %d", host, port); | |
2286 | ||
2287 | permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host); | |
2288 | permitted_opens[num_permitted_opens].port_to_connect = port; | |
2289 | num_permitted_opens++; | |
2290 | ||
2291 | all_opens_permitted = 0; | |
2292 | } | |
2293 | ||
2294 | void | |
2295 | channel_clear_permitted_opens(void) | |
2296 | { | |
2297 | int i; | |
2298 | ||
2299 | for (i = 0; i < num_permitted_opens; i++) | |
2300 | xfree(permitted_opens[i].host_to_connect); | |
2301 | num_permitted_opens = 0; | |
2302 | ||
2303 | } | |
2304 | ||
2305 | ||
2306 | /* return socket to remote host, port */ | |
2307 | static int | |
2308 | connect_to(const char *host, u_short port) | |
2309 | { | |
2310 | struct addrinfo hints, *ai, *aitop; | |
2311 | char ntop[NI_MAXHOST], strport[NI_MAXSERV]; | |
2312 | int gaierr; | |
2313 | int sock = -1; | |
2314 | ||
2315 | memset(&hints, 0, sizeof(hints)); | |
2316 | hints.ai_family = IPv4or6; | |
2317 | hints.ai_socktype = SOCK_STREAM; | |
2318 | snprintf(strport, sizeof strport, "%d", port); | |
2319 | if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) { | |
2320 | error("connect_to %.100s: unknown host (%s)", host, | |
2321 | gai_strerror(gaierr)); | |
2322 | return -1; | |
2323 | } | |
2324 | for (ai = aitop; ai; ai = ai->ai_next) { | |
2325 | if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) | |
2326 | continue; | |
2327 | if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), | |
2328 | strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) { | |
2329 | error("connect_to: getnameinfo failed"); | |
2330 | continue; | |
2331 | } | |
2332 | sock = socket(ai->ai_family, SOCK_STREAM, 0); | |
2333 | if (sock < 0) { | |
2334 | error("socket: %.100s", strerror(errno)); | |
2335 | continue; | |
2336 | } | |
2337 | if (fcntl(sock, F_SETFL, O_NONBLOCK) < 0) | |
2338 | fatal("connect_to: F_SETFL: %s", strerror(errno)); | |
2339 | if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 && | |
2340 | errno != EINPROGRESS) { | |
2341 | error("connect_to %.100s port %s: %.100s", ntop, strport, | |
2342 | strerror(errno)); | |
2343 | close(sock); | |
2344 | continue; /* fail -- try next */ | |
2345 | } | |
2346 | break; /* success */ | |
2347 | ||
2348 | } | |
2349 | freeaddrinfo(aitop); | |
2350 | if (!ai) { | |
2351 | error("connect_to %.100s port %d: failed.", host, port); | |
2352 | return -1; | |
2353 | } | |
2354 | /* success */ | |
2355 | return sock; | |
2356 | } | |
2357 | ||
2358 | int | |
2359 | channel_connect_by_listen_address(u_short listen_port) | |
2360 | { | |
2361 | int i; | |
2362 | ||
2363 | for (i = 0; i < num_permitted_opens; i++) | |
2364 | if (permitted_opens[i].listen_port == listen_port) | |
2365 | return connect_to( | |
2366 | permitted_opens[i].host_to_connect, | |
2367 | permitted_opens[i].port_to_connect); | |
2368 | error("WARNING: Server requests forwarding for unknown listen_port %d", | |
2369 | listen_port); | |
2370 | return -1; | |
2371 | } | |
2372 | ||
2373 | /* Check if connecting to that port is permitted and connect. */ | |
2374 | int | |
2375 | channel_connect_to(const char *host, u_short port) | |
2376 | { | |
2377 | int i, permit; | |
2378 | ||
2379 | permit = all_opens_permitted; | |
2380 | if (!permit) { | |
2381 | for (i = 0; i < num_permitted_opens; i++) | |
2382 | if (permitted_opens[i].port_to_connect == port && | |
2383 | strcmp(permitted_opens[i].host_to_connect, host) == 0) | |
2384 | permit = 1; | |
2385 | ||
2386 | } | |
2387 | if (!permit) { | |
2388 | log("Received request to connect to host %.100s port %d, " | |
2389 | "but the request was denied.", host, port); | |
2390 | return -1; | |
2391 | } | |
2392 | return connect_to(host, port); | |
2393 | } | |
2394 | ||
2395 | /* -- X11 forwarding */ | |
2396 | ||
2397 | /* | |
2398 | * Creates an internet domain socket for listening for X11 connections. | |
2399 | * Returns a suitable value for the DISPLAY variable, or NULL if an error | |
2400 | * occurs. | |
2401 | */ | |
2402 | char * | |
2403 | x11_create_display_inet(int screen_number, int x11_display_offset) | |
2404 | { | |
2405 | int display_number, sock; | |
2406 | u_short port; | |
2407 | struct addrinfo hints, *ai, *aitop; | |
2408 | char strport[NI_MAXSERV]; | |
2409 | int gaierr, n, num_socks = 0, socks[NUM_SOCKS]; | |
2410 | char display[512]; | |
2411 | char hostname[MAXHOSTNAMELEN]; | |
2412 | ||
2413 | for (display_number = x11_display_offset; | |
2414 | display_number < MAX_DISPLAYS; | |
2415 | display_number++) { | |
2416 | port = 6000 + display_number; | |
2417 | memset(&hints, 0, sizeof(hints)); | |
2418 | hints.ai_family = IPv4or6; | |
2419 | hints.ai_flags = AI_PASSIVE; /* XXX loopback only ? */ | |
2420 | hints.ai_socktype = SOCK_STREAM; | |
2421 | snprintf(strport, sizeof strport, "%d", port); | |
2422 | if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) { | |
2423 | error("getaddrinfo: %.100s", gai_strerror(gaierr)); | |
2424 | return NULL; | |
2425 | } | |
2426 | for (ai = aitop; ai; ai = ai->ai_next) { | |
2427 | if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) | |
2428 | continue; | |
2429 | sock = socket(ai->ai_family, SOCK_STREAM, 0); | |
2430 | if (sock < 0) { | |
2431 | if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) { | |
2432 | error("socket: %.100s", strerror(errno)); | |
2433 | return NULL; | |
2434 | } else { | |
2435 | debug("x11_create_display_inet: Socket family %d not supported", | |
2436 | ai->ai_family); | |
2437 | continue; | |
2438 | } | |
2439 | } | |
2440 | if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) { | |
2441 | debug("bind port %d: %.100s", port, strerror(errno)); | |
2442 | shutdown(sock, SHUT_RDWR); | |
2443 | close(sock); | |
2444 | ||
2445 | if (ai->ai_next) | |
2446 | continue; | |
2447 | ||
2448 | for (n = 0; n < num_socks; n++) { | |
2449 | shutdown(socks[n], SHUT_RDWR); | |
2450 | close(socks[n]); | |
2451 | } | |
2452 | num_socks = 0; | |
2453 | break; | |
2454 | } | |
2455 | socks[num_socks++] = sock; | |
2456 | #ifndef DONT_TRY_OTHER_AF | |
2457 | if (num_socks == NUM_SOCKS) | |
2458 | break; | |
2459 | #else | |
2460 | break; | |
2461 | #endif | |
2462 | } | |
2463 | freeaddrinfo(aitop); | |
2464 | if (num_socks > 0) | |
2465 | break; | |
2466 | } | |
2467 | if (display_number >= MAX_DISPLAYS) { | |
2468 | error("Failed to allocate internet-domain X11 display socket."); | |
2469 | return NULL; | |
2470 | } | |
2471 | /* Start listening for connections on the socket. */ | |
2472 | for (n = 0; n < num_socks; n++) { | |
2473 | sock = socks[n]; | |
2474 | if (listen(sock, 5) < 0) { | |
2475 | error("listen: %.100s", strerror(errno)); | |
2476 | shutdown(sock, SHUT_RDWR); | |
2477 | close(sock); | |
2478 | return NULL; | |
2479 | } | |
2480 | } | |
2481 | ||
2482 | /* Set up a suitable value for the DISPLAY variable. */ | |
2483 | if (gethostname(hostname, sizeof(hostname)) < 0) | |
2484 | fatal("gethostname: %.100s", strerror(errno)); | |
2485 | ||
2486 | #ifdef IPADDR_IN_DISPLAY | |
2487 | /* | |
2488 | * HPUX detects the local hostname in the DISPLAY variable and tries | |
2489 | * to set up a shared memory connection to the server, which it | |
2490 | * incorrectly supposes to be local. | |
2491 | * | |
2492 | * The workaround - as used in later $$H and other programs - is | |
2493 | * is to set display to the host's IP address. | |
2494 | */ | |
2495 | { | |
2496 | struct hostent *he; | |
2497 | struct in_addr my_addr; | |
2498 | ||
2499 | he = gethostbyname(hostname); | |
2500 | if (he == NULL) { | |
2501 | error("[X11-broken-fwd-hostname-workaround] Could not get " | |
2502 | "IP address for hostname %s.", hostname); | |
2503 | ||
2504 | packet_send_debug("[X11-broken-fwd-hostname-workaround]" | |
2505 | "Could not get IP address for hostname %s.", hostname); | |
2506 | ||
2507 | shutdown(sock, SHUT_RDWR); | |
2508 | close(sock); | |
2509 | ||
2510 | return NULL; | |
2511 | } | |
2512 | ||
2513 | memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr)); | |
2514 | ||
2515 | /* Set DISPLAY to <ip address>:screen.display */ | |
2516 | snprintf(display, sizeof(display), "%.50s:%d.%d", inet_ntoa(my_addr), | |
2517 | display_number, screen_number); | |
2518 | } | |
2519 | #else /* IPADDR_IN_DISPLAY */ | |
2520 | /* Just set DISPLAY to hostname:screen.display */ | |
2521 | snprintf(display, sizeof display, "%.400s:%d.%d", hostname, | |
2522 | display_number, screen_number); | |
2523 | #endif /* IPADDR_IN_DISPLAY */ | |
2524 | ||
2525 | /* Allocate a channel for each socket. */ | |
2526 | for (n = 0; n < num_socks; n++) { | |
2527 | sock = socks[n]; | |
2528 | (void) channel_new("x11 listener", | |
2529 | SSH_CHANNEL_X11_LISTENER, sock, sock, -1, | |
2530 | CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, | |
2531 | 0, xstrdup("X11 inet listener"), 1); | |
2532 | } | |
2533 | ||
2534 | /* Return a suitable value for the DISPLAY environment variable. */ | |
2535 | return xstrdup(display); | |
2536 | } | |
2537 | ||
2538 | #ifndef X_UNIX_PATH | |
2539 | #define X_UNIX_PATH "/tmp/.X11-unix/X" | |
2540 | #endif | |
2541 | ||
2542 | static int | |
2543 | connect_local_xsocket(u_int dnr) | |
2544 | { | |
2545 | static const char *const x_sockets[] = { | |
2546 | X_UNIX_PATH "%u", | |
2547 | "/var/X/.X11-unix/X" "%u", | |
2548 | "/usr/spool/sockets/X11/" "%u", | |
2549 | NULL | |
2550 | }; | |
2551 | int sock; | |
2552 | struct sockaddr_un addr; | |
2553 | const char *const * path; | |
2554 | ||
2555 | for (path = x_sockets; *path; ++path) { | |
2556 | sock = socket(AF_UNIX, SOCK_STREAM, 0); | |
2557 | if (sock < 0) | |
2558 | error("socket: %.100s", strerror(errno)); | |
2559 | memset(&addr, 0, sizeof(addr)); | |
2560 | addr.sun_family = AF_UNIX; | |
2561 | snprintf(addr.sun_path, sizeof addr.sun_path, *path, dnr); | |
2562 | if (connect(sock, (struct sockaddr *) & addr, sizeof(addr)) == 0) | |
2563 | return sock; | |
2564 | close(sock); | |
2565 | } | |
2566 | error("connect %.100s: %.100s", addr.sun_path, strerror(errno)); | |
2567 | return -1; | |
2568 | } | |
2569 | ||
2570 | int | |
2571 | x11_connect_display(void) | |
2572 | { | |
2573 | int display_number, sock = 0; | |
2574 | const char *display; | |
2575 | char buf[1024], *cp; | |
2576 | struct addrinfo hints, *ai, *aitop; | |
2577 | char strport[NI_MAXSERV]; | |
2578 | int gaierr; | |
2579 | ||
2580 | /* Try to open a socket for the local X server. */ | |
2581 | display = getenv("DISPLAY"); | |
2582 | if (!display) { | |
2583 | error("DISPLAY not set."); | |
2584 | return -1; | |
2585 | } | |
2586 | /* | |
2587 | * Now we decode the value of the DISPLAY variable and make a | |
2588 | * connection to the real X server. | |
2589 | */ | |
2590 | ||
2591 | /* | |
2592 | * Check if it is a unix domain socket. Unix domain displays are in | |
2593 | * one of the following formats: unix:d[.s], :d[.s], ::d[.s] | |
2594 | */ | |
2595 | if (strncmp(display, "unix:", 5) == 0 || | |
2596 | display[0] == ':') { | |
2597 | /* Connect to the unix domain socket. */ | |
2598 | if (sscanf(strrchr(display, ':') + 1, "%d", &display_number) != 1) { | |
2599 | error("Could not parse display number from DISPLAY: %.100s", | |
2600 | display); | |
2601 | return -1; | |
2602 | } | |
2603 | /* Create a socket. */ | |
2604 | sock = connect_local_xsocket(display_number); | |
2605 | if (sock < 0) | |
2606 | return -1; | |
2607 | ||
2608 | /* OK, we now have a connection to the display. */ | |
2609 | return sock; | |
2610 | } | |
2611 | /* | |
2612 | * Connect to an inet socket. The DISPLAY value is supposedly | |
2613 | * hostname:d[.s], where hostname may also be numeric IP address. | |
2614 | */ | |
2615 | strncpy(buf, display, sizeof(buf)); | |
2616 | buf[sizeof(buf) - 1] = 0; | |
2617 | cp = strchr(buf, ':'); | |
2618 | if (!cp) { | |
2619 | error("Could not find ':' in DISPLAY: %.100s", display); | |
2620 | return -1; | |
2621 | } | |
2622 | *cp = 0; | |
2623 | /* buf now contains the host name. But first we parse the display number. */ | |
2624 | if (sscanf(cp + 1, "%d", &display_number) != 1) { | |
2625 | error("Could not parse display number from DISPLAY: %.100s", | |
2626 | display); | |
2627 | return -1; | |
2628 | } | |
2629 | ||
2630 | /* Look up the host address */ | |
2631 | memset(&hints, 0, sizeof(hints)); | |
2632 | hints.ai_family = IPv4or6; | |
2633 | hints.ai_socktype = SOCK_STREAM; | |
2634 | snprintf(strport, sizeof strport, "%d", 6000 + display_number); | |
2635 | if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) { | |
2636 | error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr)); | |
2637 | return -1; | |
2638 | } | |
2639 | for (ai = aitop; ai; ai = ai->ai_next) { | |
2640 | /* Create a socket. */ | |
2641 | sock = socket(ai->ai_family, SOCK_STREAM, 0); | |
2642 | if (sock < 0) { | |
2643 | debug("socket: %.100s", strerror(errno)); | |
2644 | continue; | |
2645 | } | |
2646 | /* Connect it to the display. */ | |
2647 | if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) { | |
2648 | debug("connect %.100s port %d: %.100s", buf, | |
2649 | 6000 + display_number, strerror(errno)); | |
2650 | close(sock); | |
2651 | continue; | |
2652 | } | |
2653 | /* Success */ | |
2654 | break; | |
2655 | } | |
2656 | freeaddrinfo(aitop); | |
2657 | if (!ai) { | |
2658 | error("connect %.100s port %d: %.100s", buf, 6000 + display_number, | |
2659 | strerror(errno)); | |
2660 | return -1; | |
2661 | } | |
2662 | return sock; | |
2663 | } | |
2664 | ||
2665 | /* | |
2666 | * This is called when SSH_SMSG_X11_OPEN is received. The packet contains | |
2667 | * the remote channel number. We should do whatever we want, and respond | |
2668 | * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE. | |
2669 | */ | |
2670 | ||
2671 | void | |
2672 | x11_input_open(int type, int plen, void *ctxt) | |
2673 | { | |
2674 | Channel *c = NULL; | |
2675 | int remote_id, sock = 0; | |
2676 | char *remote_host; | |
2677 | ||
2678 | debug("Received X11 open request."); | |
2679 | ||
2680 | remote_id = packet_get_int(); | |
2681 | ||
2682 | if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) { | |
2683 | remote_host = packet_get_string(NULL); | |
2684 | } else { | |
2685 | remote_host = xstrdup("unknown (remote did not supply name)"); | |
2686 | } | |
2687 | packet_done(); | |
2688 | ||
2689 | /* Obtain a connection to the real X display. */ | |
2690 | sock = x11_connect_display(); | |
2691 | if (sock != -1) { | |
2692 | /* Allocate a channel for this connection. */ | |
2693 | c = channel_new("connected x11 socket", | |
2694 | SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0, | |
2695 | remote_host, 1); | |
2696 | if (c == NULL) { | |
2697 | error("x11_input_open: channel_new failed"); | |
2698 | close(sock); | |
2699 | } else { | |
2700 | c->remote_id = remote_id; | |
2701 | c->force_drain = 1; | |
2702 | } | |
2703 | } | |
2704 | if (c == NULL) { | |
2705 | /* Send refusal to the remote host. */ | |
2706 | packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); | |
2707 | packet_put_int(remote_id); | |
2708 | } else { | |
2709 | /* Send a confirmation to the remote host. */ | |
2710 | packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION); | |
2711 | packet_put_int(remote_id); | |
2712 | packet_put_int(c->self); | |
2713 | } | |
2714 | packet_send(); | |
2715 | } | |
2716 | ||
2717 | /* dummy protocol handler that denies SSH-1 requests (agent/x11) */ | |
2718 | void | |
2719 | deny_input_open(int type, int plen, void *ctxt) | |
2720 | { | |
2721 | int rchan = packet_get_int(); | |
2722 | switch(type){ | |
2723 | case SSH_SMSG_AGENT_OPEN: | |
2724 | error("Warning: ssh server tried agent forwarding."); | |
2725 | break; | |
2726 | case SSH_SMSG_X11_OPEN: | |
2727 | error("Warning: ssh server tried X11 forwarding."); | |
2728 | break; | |
2729 | default: | |
2730 | error("deny_input_open: type %d plen %d", type, plen); | |
2731 | break; | |
2732 | } | |
2733 | error("Warning: this is probably a break in attempt by a malicious server."); | |
2734 | packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); | |
2735 | packet_put_int(rchan); | |
2736 | packet_send(); | |
2737 | } | |
2738 | ||
2739 | /* | |
2740 | * Requests forwarding of X11 connections, generates fake authentication | |
2741 | * data, and enables authentication spoofing. | |
2742 | * This should be called in the client only. | |
2743 | */ | |
2744 | void | |
2745 | x11_request_forwarding_with_spoofing(int client_session_id, | |
2746 | const char *proto, const char *data) | |
2747 | { | |
2748 | u_int data_len = (u_int) strlen(data) / 2; | |
2749 | u_int i, value, len; | |
2750 | char *new_data; | |
2751 | int screen_number; | |
2752 | const char *cp; | |
2753 | u_int32_t rand = 0; | |
2754 | ||
2755 | cp = getenv("DISPLAY"); | |
2756 | if (cp) | |
2757 | cp = strchr(cp, ':'); | |
2758 | if (cp) | |
2759 | cp = strchr(cp, '.'); | |
2760 | if (cp) | |
2761 | screen_number = atoi(cp + 1); | |
2762 | else | |
2763 | screen_number = 0; | |
2764 | ||
2765 | /* Save protocol name. */ | |
2766 | x11_saved_proto = xstrdup(proto); | |
2767 | ||
2768 | /* | |
2769 | * Extract real authentication data and generate fake data of the | |
2770 | * same length. | |
2771 | */ | |
2772 | x11_saved_data = xmalloc(data_len); | |
2773 | x11_fake_data = xmalloc(data_len); | |
2774 | for (i = 0; i < data_len; i++) { | |
2775 | if (sscanf(data + 2 * i, "%2x", &value) != 1) | |
2776 | fatal("x11_request_forwarding: bad authentication data: %.100s", data); | |
2777 | if (i % 4 == 0) | |
2778 | rand = arc4random(); | |
2779 | x11_saved_data[i] = value; | |
2780 | x11_fake_data[i] = rand & 0xff; | |
2781 | rand >>= 8; | |
2782 | } | |
2783 | x11_saved_data_len = data_len; | |
2784 | x11_fake_data_len = data_len; | |
2785 | ||
2786 | /* Convert the fake data into hex. */ | |
2787 | len = 2 * data_len + 1; | |
2788 | new_data = xmalloc(len); | |
2789 | for (i = 0; i < data_len; i++) | |
2790 | snprintf(new_data + 2 * i, len - 2 * i, | |
2791 | "%02x", (u_char) x11_fake_data[i]); | |
2792 | ||
2793 | /* Send the request packet. */ | |
2794 | if (compat20) { | |
2795 | channel_request_start(client_session_id, "x11-req", 0); | |
2796 | packet_put_char(0); /* XXX bool single connection */ | |
2797 | } else { | |
2798 | packet_start(SSH_CMSG_X11_REQUEST_FORWARDING); | |
2799 | } | |
2800 | packet_put_cstring(proto); | |
2801 | packet_put_cstring(new_data); | |
2802 | packet_put_int(screen_number); | |
2803 | packet_send(); | |
2804 | packet_write_wait(); | |
2805 | xfree(new_data); | |
2806 | } | |
2807 | ||
2808 | ||
2809 | /* -- agent forwarding */ | |
2810 | ||
2811 | /* Sends a message to the server to request authentication fd forwarding. */ | |
2812 | ||
2813 | void | |
2814 | auth_request_forwarding() | |
2815 | { | |
2816 | packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING); | |
2817 | packet_send(); | |
2818 | packet_write_wait(); | |
2819 | } | |
2820 | ||
2821 | /* | |
2822 | * Returns the name of the forwarded authentication socket. Returns NULL if | |
2823 | * there is no forwarded authentication socket. The returned value points to | |
2824 | * a static buffer. | |
2825 | */ | |
2826 | ||
2827 | char * | |
2828 | auth_get_socket_name() | |
2829 | { | |
2830 | return auth_sock_name; | |
2831 | } | |
2832 | ||
2833 | /* removes the agent forwarding socket */ | |
2834 | ||
2835 | void | |
2836 | auth_sock_cleanup_proc(void *_pw) | |
2837 | { | |
2838 | struct passwd *pw = _pw; | |
2839 | ||
2840 | if (auth_sock_name) { | |
2841 | temporarily_use_uid(pw); | |
2842 | unlink(auth_sock_name); | |
2843 | rmdir(auth_sock_dir); | |
2844 | auth_sock_name = NULL; | |
2845 | restore_uid(); | |
2846 | } | |
2847 | } | |
2848 | ||
2849 | /* | |
2850 | * This is called to process SSH_CMSG_AGENT_REQUEST_FORWARDING on the server. | |
2851 | * This starts forwarding authentication requests. | |
2852 | */ | |
2853 | ||
2854 | int | |
2855 | auth_input_request_forwarding(struct passwd * pw) | |
2856 | { | |
2857 | Channel *nc; | |
2858 | int sock; | |
2859 | struct sockaddr_un sunaddr; | |
2860 | ||
2861 | if (auth_get_socket_name() != NULL) { | |
2862 | error("authentication forwarding requested twice."); | |
2863 | return 0; | |
2864 | } | |
2865 | ||
2866 | /* Temporarily drop privileged uid for mkdir/bind. */ | |
2867 | temporarily_use_uid(pw); | |
2868 | ||
2869 | /* Allocate a buffer for the socket name, and format the name. */ | |
2870 | auth_sock_name = xmalloc(MAXPATHLEN); | |
2871 | auth_sock_dir = xmalloc(MAXPATHLEN); | |
2872 | strlcpy(auth_sock_dir, "/tmp/ssh-XXXXXXXX", MAXPATHLEN); | |
2873 | ||
2874 | /* Create private directory for socket */ | |
2875 | if (mkdtemp(auth_sock_dir) == NULL) { | |
2876 | packet_send_debug("Agent forwarding disabled: " | |
2877 | "mkdtemp() failed: %.100s", strerror(errno)); | |
2878 | restore_uid(); | |
2879 | xfree(auth_sock_name); | |
2880 | xfree(auth_sock_dir); | |
2881 | auth_sock_name = NULL; | |
2882 | auth_sock_dir = NULL; | |
2883 | return 0; | |
2884 | } | |
2885 | snprintf(auth_sock_name, MAXPATHLEN, "%s/agent.%d", | |
2886 | auth_sock_dir, (int) getpid()); | |
2887 | ||
2888 | /* delete agent socket on fatal() */ | |
2889 | fatal_add_cleanup(auth_sock_cleanup_proc, pw); | |
2890 | ||
2891 | /* Create the socket. */ | |
2892 | sock = socket(AF_UNIX, SOCK_STREAM, 0); | |
2893 | if (sock < 0) | |
2894 | packet_disconnect("socket: %.100s", strerror(errno)); | |
2895 | ||
2896 | /* Bind it to the name. */ | |
2897 | memset(&sunaddr, 0, sizeof(sunaddr)); | |
2898 | sunaddr.sun_family = AF_UNIX; | |
2899 | strncpy(sunaddr.sun_path, auth_sock_name, | |
2900 | sizeof(sunaddr.sun_path)); | |
2901 | ||
2902 | if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0) | |
2903 | packet_disconnect("bind: %.100s", strerror(errno)); | |
2904 | ||
2905 | /* Restore the privileged uid. */ | |
2906 | restore_uid(); | |
2907 | ||
2908 | /* Start listening on the socket. */ | |
2909 | if (listen(sock, 5) < 0) | |
2910 | packet_disconnect("listen: %.100s", strerror(errno)); | |
2911 | ||
2912 | /* Allocate a channel for the authentication agent socket. */ | |
2913 | nc = channel_new("auth socket", | |
2914 | SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1, | |
2915 | CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, | |
2916 | 0, xstrdup("auth socket"), 1); | |
2917 | if (nc == NULL) { | |
2918 | error("auth_input_request_forwarding: channel_new failed"); | |
2919 | auth_sock_cleanup_proc(pw); | |
2920 | fatal_remove_cleanup(auth_sock_cleanup_proc, pw); | |
2921 | close(sock); | |
2922 | return 0; | |
2923 | } | |
2924 | strlcpy(nc->path, auth_sock_name, sizeof(nc->path)); | |
2925 | return 1; | |
2926 | } | |
2927 | ||
2928 | /* This is called to process an SSH_SMSG_AGENT_OPEN message. */ | |
2929 | ||
2930 | void | |
2931 | auth_input_open_request(int type, int plen, void *ctxt) | |
2932 | { | |
2933 | Channel *c = NULL; | |
2934 | int remote_id, sock; | |
2935 | char *name; | |
2936 | ||
2937 | packet_integrity_check(plen, 4, type); | |
2938 | ||
2939 | /* Read the remote channel number from the message. */ | |
2940 | remote_id = packet_get_int(); | |
2941 | ||
2942 | /* | |
2943 | * Get a connection to the local authentication agent (this may again | |
2944 | * get forwarded). | |
2945 | */ | |
2946 | sock = ssh_get_authentication_socket(); | |
2947 | ||
2948 | /* | |
2949 | * If we could not connect the agent, send an error message back to | |
2950 | * the server. This should never happen unless the agent dies, | |
2951 | * because authentication forwarding is only enabled if we have an | |
2952 | * agent. | |
2953 | */ | |
2954 | if (sock >= 0) { | |
2955 | name = xstrdup("authentication agent connection"); | |
2956 | c = channel_new("", SSH_CHANNEL_OPEN, sock, sock, | |
2957 | -1, 0, 0, 0, name, 1); | |
2958 | if (c == NULL) { | |
2959 | error("auth_input_open_request: channel_new failed"); | |
2960 | xfree(name); | |
2961 | close(sock); | |
2962 | } else { | |
2963 | c->remote_id = remote_id; | |
2964 | c->force_drain = 1; | |
2965 | } | |
2966 | } | |
2967 | if (c == NULL) { | |
2968 | packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); | |
2969 | packet_put_int(remote_id); | |
2970 | } else { | |
2971 | /* Send a confirmation to the remote host. */ | |
2972 | debug("Forwarding authentication connection."); | |
2973 | packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION); | |
2974 | packet_put_int(remote_id); | |
2975 | packet_put_int(c->self); | |
2976 | } | |
2977 | packet_send(); | |
2978 | } |