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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. | |
1e608e42 | 16 | * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved. |
3c0ef626 | 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" | |
1e608e42 | 42 | RCSID("$OpenBSD: channels.c,v 1.171 2002/03/04 19:37:58 markus Exp $"); |
3c0ef626 | 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" | |
1e608e42 | 57 | #include "pathnames.h" |
3c0ef626 | 58 | |
59 | ||
60 | /* -- channel core */ | |
61 | ||
62 | /* | |
63 | * Pointer to an array containing all allocated channels. The array is | |
64 | * dynamically extended as needed. | |
65 | */ | |
66 | static Channel **channels = NULL; | |
67 | ||
68 | /* | |
69 | * Size of the channel array. All slots of the array must always be | |
70 | * initialized (at least the type field); unused slots set to NULL | |
71 | */ | |
72 | static int channels_alloc = 0; | |
73 | ||
74 | /* | |
75 | * Maximum file descriptor value used in any of the channels. This is | |
76 | * updated in channel_new. | |
77 | */ | |
78 | static int channel_max_fd = 0; | |
79 | ||
80 | ||
81 | /* -- tcp forwarding */ | |
82 | ||
83 | /* | |
84 | * Data structure for storing which hosts are permitted for forward requests. | |
85 | * The local sides of any remote forwards are stored in this array to prevent | |
86 | * a corrupt remote server from accessing arbitrary TCP/IP ports on our local | |
87 | * network (which might be behind a firewall). | |
88 | */ | |
89 | typedef struct { | |
90 | char *host_to_connect; /* Connect to 'host'. */ | |
91 | u_short port_to_connect; /* Connect to 'port'. */ | |
92 | u_short listen_port; /* Remote side should listen port number. */ | |
93 | } ForwardPermission; | |
94 | ||
95 | /* List of all permitted host/port pairs to connect. */ | |
96 | static ForwardPermission permitted_opens[SSH_MAX_FORWARDS_PER_DIRECTION]; | |
97 | ||
98 | /* Number of permitted host/port pairs in the array. */ | |
99 | static int num_permitted_opens = 0; | |
100 | /* | |
101 | * If this is true, all opens are permitted. This is the case on the server | |
102 | * on which we have to trust the client anyway, and the user could do | |
103 | * anything after logging in anyway. | |
104 | */ | |
105 | static int all_opens_permitted = 0; | |
106 | ||
107 | ||
108 | /* -- X11 forwarding */ | |
109 | ||
110 | /* Maximum number of fake X11 displays to try. */ | |
111 | #define MAX_DISPLAYS 1000 | |
112 | ||
113 | /* Saved X11 authentication protocol name. */ | |
114 | static char *x11_saved_proto = NULL; | |
115 | ||
116 | /* Saved X11 authentication data. This is the real data. */ | |
117 | static char *x11_saved_data = NULL; | |
118 | static u_int x11_saved_data_len = 0; | |
119 | ||
120 | /* | |
121 | * Fake X11 authentication data. This is what the server will be sending us; | |
122 | * we should replace any occurrences of this by the real data. | |
123 | */ | |
124 | static char *x11_fake_data = NULL; | |
125 | static u_int x11_fake_data_len; | |
126 | ||
127 | ||
128 | /* -- agent forwarding */ | |
129 | ||
130 | #define NUM_SOCKS 10 | |
131 | ||
132 | /* Name and directory of socket for authentication agent forwarding. */ | |
133 | static char *auth_sock_name = NULL; | |
134 | static char *auth_sock_dir = NULL; | |
135 | ||
136 | /* AF_UNSPEC or AF_INET or AF_INET6 */ | |
137 | static int IPv4or6 = AF_UNSPEC; | |
138 | ||
139 | /* helper */ | |
140 | static void port_open_helper(Channel *c, char *rtype); | |
141 | ||
142 | /* -- channel core */ | |
143 | ||
144 | Channel * | |
145 | channel_lookup(int id) | |
146 | { | |
147 | Channel *c; | |
148 | ||
1e608e42 | 149 | if (id < 0 || id >= channels_alloc) { |
3c0ef626 | 150 | log("channel_lookup: %d: bad id", id); |
151 | return NULL; | |
152 | } | |
153 | c = channels[id]; | |
154 | if (c == NULL) { | |
155 | log("channel_lookup: %d: bad id: channel free", id); | |
156 | return NULL; | |
157 | } | |
158 | return c; | |
159 | } | |
160 | ||
161 | /* | |
162 | * Register filedescriptors for a channel, used when allocating a channel or | |
163 | * when the channel consumer/producer is ready, e.g. shell exec'd | |
164 | */ | |
165 | ||
166 | static void | |
167 | channel_register_fds(Channel *c, int rfd, int wfd, int efd, | |
168 | int extusage, int nonblock) | |
169 | { | |
170 | /* Update the maximum file descriptor value. */ | |
171 | channel_max_fd = MAX(channel_max_fd, rfd); | |
172 | channel_max_fd = MAX(channel_max_fd, wfd); | |
173 | channel_max_fd = MAX(channel_max_fd, efd); | |
174 | ||
175 | /* XXX set close-on-exec -markus */ | |
176 | ||
177 | c->rfd = rfd; | |
178 | c->wfd = wfd; | |
179 | c->sock = (rfd == wfd) ? rfd : -1; | |
180 | c->efd = efd; | |
181 | c->extended_usage = extusage; | |
182 | ||
183 | /* XXX ugly hack: nonblock is only set by the server */ | |
184 | if (nonblock && isatty(c->rfd)) { | |
185 | debug("channel %d: rfd %d isatty", c->self, c->rfd); | |
186 | c->isatty = 1; | |
187 | if (!isatty(c->wfd)) { | |
188 | error("channel %d: wfd %d is not a tty?", | |
189 | c->self, c->wfd); | |
190 | } | |
191 | } else { | |
192 | c->isatty = 0; | |
193 | } | |
194 | ||
195 | /* enable nonblocking mode */ | |
196 | if (nonblock) { | |
197 | if (rfd != -1) | |
198 | set_nonblock(rfd); | |
199 | if (wfd != -1) | |
200 | set_nonblock(wfd); | |
201 | if (efd != -1) | |
202 | set_nonblock(efd); | |
203 | } | |
204 | } | |
205 | ||
206 | /* | |
207 | * Allocate a new channel object and set its type and socket. This will cause | |
208 | * remote_name to be freed. | |
209 | */ | |
210 | ||
211 | Channel * | |
212 | channel_new(char *ctype, int type, int rfd, int wfd, int efd, | |
213 | int window, int maxpack, int extusage, char *remote_name, int nonblock) | |
214 | { | |
215 | int i, found; | |
216 | Channel *c; | |
217 | ||
218 | /* Do initial allocation if this is the first call. */ | |
219 | if (channels_alloc == 0) { | |
3c0ef626 | 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); | |
1e608e42 | 248 | c->ostate = CHAN_OUTPUT_OPEN; |
249 | c->istate = CHAN_INPUT_OPEN; | |
250 | c->flags = 0; | |
3c0ef626 | 251 | channel_register_fds(c, rfd, wfd, efd, extusage, nonblock); |
252 | c->self = found; | |
253 | c->type = type; | |
254 | c->ctype = ctype; | |
255 | c->local_window = window; | |
256 | c->local_window_max = window; | |
257 | c->local_consumed = 0; | |
258 | c->local_maxpacket = maxpack; | |
259 | c->remote_id = -1; | |
260 | c->remote_name = remote_name; | |
261 | c->remote_window = 0; | |
262 | c->remote_maxpacket = 0; | |
3c0ef626 | 263 | c->force_drain = 0; |
1e608e42 | 264 | c->single_connection = 0; |
3c0ef626 | 265 | c->detach_user = NULL; |
1e608e42 | 266 | c->confirm = NULL; |
3c0ef626 | 267 | c->input_filter = NULL; |
268 | debug("channel %d: new [%s]", found, remote_name); | |
269 | return c; | |
270 | } | |
271 | ||
272 | static int | |
273 | channel_find_maxfd(void) | |
274 | { | |
275 | int i, max = 0; | |
276 | Channel *c; | |
277 | ||
278 | for (i = 0; i < channels_alloc; i++) { | |
279 | c = channels[i]; | |
280 | if (c != NULL) { | |
281 | max = MAX(max, c->rfd); | |
282 | max = MAX(max, c->wfd); | |
283 | max = MAX(max, c->efd); | |
284 | } | |
285 | } | |
286 | return max; | |
287 | } | |
288 | ||
289 | int | |
290 | channel_close_fd(int *fdp) | |
291 | { | |
292 | int ret = 0, fd = *fdp; | |
293 | ||
294 | if (fd != -1) { | |
295 | ret = close(fd); | |
296 | *fdp = -1; | |
297 | if (fd == channel_max_fd) | |
298 | channel_max_fd = channel_find_maxfd(); | |
299 | } | |
300 | return ret; | |
301 | } | |
302 | ||
303 | /* Close all channel fd/socket. */ | |
304 | ||
305 | static void | |
306 | channel_close_fds(Channel *c) | |
307 | { | |
308 | debug3("channel_close_fds: channel %d: r %d w %d e %d", | |
309 | c->self, c->rfd, c->wfd, c->efd); | |
310 | ||
311 | channel_close_fd(&c->sock); | |
312 | channel_close_fd(&c->rfd); | |
313 | channel_close_fd(&c->wfd); | |
314 | channel_close_fd(&c->efd); | |
315 | } | |
316 | ||
317 | /* Free the channel and close its fd/socket. */ | |
318 | ||
319 | void | |
320 | channel_free(Channel *c) | |
321 | { | |
322 | char *s; | |
323 | int i, n; | |
324 | ||
325 | for (n = 0, i = 0; i < channels_alloc; i++) | |
326 | if (channels[i]) | |
327 | n++; | |
328 | debug("channel_free: channel %d: %s, nchannels %d", c->self, | |
329 | c->remote_name ? c->remote_name : "???", n); | |
330 | ||
331 | s = channel_open_message(); | |
332 | debug3("channel_free: status: %s", s); | |
333 | xfree(s); | |
334 | ||
335 | if (c->sock != -1) | |
336 | shutdown(c->sock, SHUT_RDWR); | |
337 | channel_close_fds(c); | |
338 | buffer_free(&c->input); | |
339 | buffer_free(&c->output); | |
340 | buffer_free(&c->extended); | |
341 | if (c->remote_name) { | |
342 | xfree(c->remote_name); | |
343 | c->remote_name = NULL; | |
344 | } | |
345 | channels[c->self] = NULL; | |
346 | xfree(c); | |
347 | } | |
348 | ||
349 | void | |
350 | channel_free_all(void) | |
351 | { | |
352 | int i; | |
353 | ||
354 | for (i = 0; i < channels_alloc; i++) | |
355 | if (channels[i] != NULL) | |
356 | channel_free(channels[i]); | |
357 | } | |
358 | ||
359 | /* | |
360 | * Closes the sockets/fds of all channels. This is used to close extra file | |
361 | * descriptors after a fork. | |
362 | */ | |
363 | ||
364 | void | |
1e608e42 | 365 | channel_close_all(void) |
3c0ef626 | 366 | { |
367 | int i; | |
368 | ||
369 | for (i = 0; i < channels_alloc; i++) | |
370 | if (channels[i] != NULL) | |
371 | channel_close_fds(channels[i]); | |
372 | } | |
373 | ||
374 | /* | |
375 | * Stop listening to channels. | |
376 | */ | |
377 | ||
378 | void | |
379 | channel_stop_listening(void) | |
380 | { | |
381 | int i; | |
382 | Channel *c; | |
383 | ||
384 | for (i = 0; i < channels_alloc; i++) { | |
385 | c = channels[i]; | |
386 | if (c != NULL) { | |
387 | switch (c->type) { | |
388 | case SSH_CHANNEL_AUTH_SOCKET: | |
389 | case SSH_CHANNEL_PORT_LISTENER: | |
390 | case SSH_CHANNEL_RPORT_LISTENER: | |
391 | case SSH_CHANNEL_X11_LISTENER: | |
392 | channel_close_fd(&c->sock); | |
393 | channel_free(c); | |
394 | break; | |
395 | } | |
396 | } | |
397 | } | |
398 | } | |
399 | ||
400 | /* | |
401 | * Returns true if no channel has too much buffered data, and false if one or | |
402 | * more channel is overfull. | |
403 | */ | |
404 | ||
405 | int | |
1e608e42 | 406 | channel_not_very_much_buffered_data(void) |
3c0ef626 | 407 | { |
408 | u_int i; | |
409 | Channel *c; | |
410 | ||
411 | for (i = 0; i < channels_alloc; i++) { | |
412 | c = channels[i]; | |
413 | if (c != NULL && c->type == SSH_CHANNEL_OPEN) { | |
414 | #if 0 | |
415 | if (!compat20 && | |
416 | buffer_len(&c->input) > packet_get_maxsize()) { | |
417 | debug("channel %d: big input buffer %d", | |
418 | c->self, buffer_len(&c->input)); | |
419 | return 0; | |
420 | } | |
421 | #endif | |
422 | if (buffer_len(&c->output) > packet_get_maxsize()) { | |
423 | debug("channel %d: big output buffer %d > %d", | |
424 | c->self, buffer_len(&c->output), | |
425 | packet_get_maxsize()); | |
426 | return 0; | |
427 | } | |
428 | } | |
429 | } | |
430 | return 1; | |
431 | } | |
432 | ||
433 | /* Returns true if any channel is still open. */ | |
434 | ||
435 | int | |
1e608e42 | 436 | channel_still_open(void) |
3c0ef626 | 437 | { |
438 | int i; | |
439 | Channel *c; | |
440 | ||
441 | for (i = 0; i < channels_alloc; i++) { | |
442 | c = channels[i]; | |
443 | if (c == NULL) | |
444 | continue; | |
445 | switch (c->type) { | |
446 | case SSH_CHANNEL_X11_LISTENER: | |
447 | case SSH_CHANNEL_PORT_LISTENER: | |
448 | case SSH_CHANNEL_RPORT_LISTENER: | |
449 | case SSH_CHANNEL_CLOSED: | |
450 | case SSH_CHANNEL_AUTH_SOCKET: | |
451 | case SSH_CHANNEL_DYNAMIC: | |
452 | case SSH_CHANNEL_CONNECTING: | |
453 | case SSH_CHANNEL_ZOMBIE: | |
454 | continue; | |
455 | case SSH_CHANNEL_LARVAL: | |
456 | if (!compat20) | |
457 | fatal("cannot happen: SSH_CHANNEL_LARVAL"); | |
458 | continue; | |
459 | case SSH_CHANNEL_OPENING: | |
460 | case SSH_CHANNEL_OPEN: | |
461 | case SSH_CHANNEL_X11_OPEN: | |
462 | return 1; | |
463 | case SSH_CHANNEL_INPUT_DRAINING: | |
464 | case SSH_CHANNEL_OUTPUT_DRAINING: | |
465 | if (!compat13) | |
466 | fatal("cannot happen: OUT_DRAIN"); | |
467 | return 1; | |
468 | default: | |
469 | fatal("channel_still_open: bad channel type %d", c->type); | |
470 | /* NOTREACHED */ | |
471 | } | |
472 | } | |
473 | return 0; | |
474 | } | |
475 | ||
476 | /* Returns the id of an open channel suitable for keepaliving */ | |
477 | ||
478 | int | |
1e608e42 | 479 | channel_find_open(void) |
3c0ef626 | 480 | { |
481 | int i; | |
482 | Channel *c; | |
483 | ||
484 | for (i = 0; i < channels_alloc; i++) { | |
485 | c = channels[i]; | |
486 | if (c == NULL) | |
487 | continue; | |
488 | switch (c->type) { | |
489 | case SSH_CHANNEL_CLOSED: | |
490 | case SSH_CHANNEL_DYNAMIC: | |
491 | case SSH_CHANNEL_X11_LISTENER: | |
492 | case SSH_CHANNEL_PORT_LISTENER: | |
493 | case SSH_CHANNEL_RPORT_LISTENER: | |
494 | case SSH_CHANNEL_OPENING: | |
495 | case SSH_CHANNEL_CONNECTING: | |
496 | case SSH_CHANNEL_ZOMBIE: | |
497 | continue; | |
498 | case SSH_CHANNEL_LARVAL: | |
499 | case SSH_CHANNEL_AUTH_SOCKET: | |
500 | case SSH_CHANNEL_OPEN: | |
501 | case SSH_CHANNEL_X11_OPEN: | |
502 | return i; | |
503 | case SSH_CHANNEL_INPUT_DRAINING: | |
504 | case SSH_CHANNEL_OUTPUT_DRAINING: | |
505 | if (!compat13) | |
506 | fatal("cannot happen: OUT_DRAIN"); | |
507 | return i; | |
508 | default: | |
509 | fatal("channel_find_open: bad channel type %d", c->type); | |
510 | /* NOTREACHED */ | |
511 | } | |
512 | } | |
513 | return -1; | |
514 | } | |
515 | ||
516 | ||
517 | /* | |
518 | * Returns a message describing the currently open forwarded connections, | |
519 | * suitable for sending to the client. The message contains crlf pairs for | |
520 | * newlines. | |
521 | */ | |
522 | ||
523 | char * | |
1e608e42 | 524 | channel_open_message(void) |
3c0ef626 | 525 | { |
526 | Buffer buffer; | |
527 | Channel *c; | |
528 | char buf[1024], *cp; | |
529 | int i; | |
530 | ||
531 | buffer_init(&buffer); | |
532 | snprintf(buf, sizeof buf, "The following connections are open:\r\n"); | |
533 | buffer_append(&buffer, buf, strlen(buf)); | |
534 | for (i = 0; i < channels_alloc; i++) { | |
535 | c = channels[i]; | |
536 | if (c == NULL) | |
537 | continue; | |
538 | switch (c->type) { | |
539 | case SSH_CHANNEL_X11_LISTENER: | |
540 | case SSH_CHANNEL_PORT_LISTENER: | |
541 | case SSH_CHANNEL_RPORT_LISTENER: | |
542 | case SSH_CHANNEL_CLOSED: | |
543 | case SSH_CHANNEL_AUTH_SOCKET: | |
544 | case SSH_CHANNEL_ZOMBIE: | |
545 | continue; | |
546 | case SSH_CHANNEL_LARVAL: | |
547 | case SSH_CHANNEL_OPENING: | |
548 | case SSH_CHANNEL_CONNECTING: | |
549 | case SSH_CHANNEL_DYNAMIC: | |
550 | case SSH_CHANNEL_OPEN: | |
551 | case SSH_CHANNEL_X11_OPEN: | |
552 | case SSH_CHANNEL_INPUT_DRAINING: | |
553 | case SSH_CHANNEL_OUTPUT_DRAINING: | |
554 | snprintf(buf, sizeof buf, " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d)\r\n", | |
555 | c->self, c->remote_name, | |
556 | c->type, c->remote_id, | |
557 | c->istate, buffer_len(&c->input), | |
558 | c->ostate, buffer_len(&c->output), | |
559 | c->rfd, c->wfd); | |
560 | buffer_append(&buffer, buf, strlen(buf)); | |
561 | continue; | |
562 | default: | |
563 | fatal("channel_open_message: bad channel type %d", c->type); | |
564 | /* NOTREACHED */ | |
565 | } | |
566 | } | |
567 | buffer_append(&buffer, "\0", 1); | |
568 | cp = xstrdup(buffer_ptr(&buffer)); | |
569 | buffer_free(&buffer); | |
570 | return cp; | |
571 | } | |
572 | ||
573 | void | |
574 | channel_send_open(int id) | |
575 | { | |
576 | Channel *c = channel_lookup(id); | |
577 | if (c == NULL) { | |
578 | log("channel_send_open: %d: bad id", id); | |
579 | return; | |
580 | } | |
581 | debug("send channel open %d", id); | |
582 | packet_start(SSH2_MSG_CHANNEL_OPEN); | |
583 | packet_put_cstring(c->ctype); | |
584 | packet_put_int(c->self); | |
585 | packet_put_int(c->local_window); | |
586 | packet_put_int(c->local_maxpacket); | |
587 | packet_send(); | |
588 | } | |
589 | ||
590 | void | |
1e608e42 | 591 | channel_request_start(int local_id, char *service, int wantconfirm) |
3c0ef626 | 592 | { |
1e608e42 | 593 | Channel *c = channel_lookup(local_id); |
3c0ef626 | 594 | if (c == NULL) { |
1e608e42 | 595 | log("channel_request_start: %d: unknown channel id", local_id); |
3c0ef626 | 596 | return; |
597 | } | |
1e608e42 | 598 | debug("channel request %d: %s", local_id, service) ; |
3c0ef626 | 599 | packet_start(SSH2_MSG_CHANNEL_REQUEST); |
600 | packet_put_int(c->remote_id); | |
601 | packet_put_cstring(service); | |
602 | packet_put_char(wantconfirm); | |
603 | } | |
604 | void | |
1e608e42 | 605 | channel_register_confirm(int id, channel_callback_fn *fn) |
3c0ef626 | 606 | { |
607 | Channel *c = channel_lookup(id); | |
608 | if (c == NULL) { | |
1e608e42 | 609 | log("channel_register_comfirm: %d: bad id", id); |
3c0ef626 | 610 | return; |
611 | } | |
1e608e42 | 612 | c->confirm = fn; |
3c0ef626 | 613 | } |
614 | void | |
615 | channel_register_cleanup(int id, channel_callback_fn *fn) | |
616 | { | |
617 | Channel *c = channel_lookup(id); | |
618 | if (c == NULL) { | |
619 | log("channel_register_cleanup: %d: bad id", id); | |
620 | return; | |
621 | } | |
622 | c->detach_user = fn; | |
623 | } | |
624 | void | |
625 | channel_cancel_cleanup(int id) | |
626 | { | |
627 | Channel *c = channel_lookup(id); | |
628 | if (c == NULL) { | |
629 | log("channel_cancel_cleanup: %d: bad id", id); | |
630 | return; | |
631 | } | |
632 | c->detach_user = NULL; | |
633 | } | |
634 | void | |
635 | channel_register_filter(int id, channel_filter_fn *fn) | |
636 | { | |
637 | Channel *c = channel_lookup(id); | |
638 | if (c == NULL) { | |
639 | log("channel_register_filter: %d: bad id", id); | |
640 | return; | |
641 | } | |
642 | c->input_filter = fn; | |
643 | } | |
644 | ||
645 | void | |
646 | channel_set_fds(int id, int rfd, int wfd, int efd, | |
1e608e42 | 647 | int extusage, int nonblock, u_int window_max) |
3c0ef626 | 648 | { |
649 | Channel *c = channel_lookup(id); | |
650 | if (c == NULL || c->type != SSH_CHANNEL_LARVAL) | |
651 | fatal("channel_activate for non-larval channel %d.", id); | |
652 | channel_register_fds(c, rfd, wfd, efd, extusage, nonblock); | |
653 | c->type = SSH_CHANNEL_OPEN; | |
1e608e42 | 654 | c->local_window = c->local_window_max = window_max; |
3c0ef626 | 655 | packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST); |
656 | packet_put_int(c->remote_id); | |
657 | packet_put_int(c->local_window); | |
658 | packet_send(); | |
659 | } | |
660 | ||
661 | /* | |
662 | * 'channel_pre*' are called just before select() to add any bits relevant to | |
663 | * channels in the select bitmasks. | |
664 | */ | |
665 | /* | |
666 | * 'channel_post*': perform any appropriate operations for channels which | |
667 | * have events pending. | |
668 | */ | |
669 | typedef void chan_fn(Channel *c, fd_set * readset, fd_set * writeset); | |
670 | chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE]; | |
671 | chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE]; | |
672 | ||
673 | static void | |
674 | channel_pre_listener(Channel *c, fd_set * readset, fd_set * writeset) | |
675 | { | |
676 | FD_SET(c->sock, readset); | |
677 | } | |
678 | ||
679 | static void | |
680 | channel_pre_connecting(Channel *c, fd_set * readset, fd_set * writeset) | |
681 | { | |
682 | debug3("channel %d: waiting for connection", c->self); | |
683 | FD_SET(c->sock, writeset); | |
684 | } | |
685 | ||
686 | static void | |
687 | channel_pre_open_13(Channel *c, fd_set * readset, fd_set * writeset) | |
688 | { | |
689 | if (buffer_len(&c->input) < packet_get_maxsize()) | |
690 | FD_SET(c->sock, readset); | |
691 | if (buffer_len(&c->output) > 0) | |
692 | FD_SET(c->sock, writeset); | |
693 | } | |
694 | ||
695 | static void | |
1e608e42 | 696 | channel_pre_open(Channel *c, fd_set * readset, fd_set * writeset) |
3c0ef626 | 697 | { |
1e608e42 | 698 | u_int limit = compat20 ? c->remote_window : packet_get_maxsize(); |
3c0ef626 | 699 | |
3c0ef626 | 700 | if (c->istate == CHAN_INPUT_OPEN && |
1e608e42 | 701 | limit > 0 && |
702 | buffer_len(&c->input) < limit) | |
3c0ef626 | 703 | FD_SET(c->rfd, readset); |
704 | if (c->ostate == CHAN_OUTPUT_OPEN || | |
705 | c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { | |
706 | if (buffer_len(&c->output) > 0) { | |
707 | FD_SET(c->wfd, writeset); | |
708 | } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { | |
709 | chan_obuf_empty(c); | |
710 | } | |
711 | } | |
712 | /** XXX check close conditions, too */ | |
1e608e42 | 713 | if (compat20 && c->efd != -1) { |
3c0ef626 | 714 | if (c->extended_usage == CHAN_EXTENDED_WRITE && |
715 | buffer_len(&c->extended) > 0) | |
716 | FD_SET(c->efd, writeset); | |
717 | else if (c->extended_usage == CHAN_EXTENDED_READ && | |
718 | buffer_len(&c->extended) < c->remote_window) | |
719 | FD_SET(c->efd, readset); | |
720 | } | |
721 | } | |
722 | ||
723 | static void | |
724 | channel_pre_input_draining(Channel *c, fd_set * readset, fd_set * writeset) | |
725 | { | |
726 | if (buffer_len(&c->input) == 0) { | |
727 | packet_start(SSH_MSG_CHANNEL_CLOSE); | |
728 | packet_put_int(c->remote_id); | |
729 | packet_send(); | |
730 | c->type = SSH_CHANNEL_CLOSED; | |
731 | debug("channel %d: closing after input drain.", c->self); | |
732 | } | |
733 | } | |
734 | ||
735 | static void | |
736 | channel_pre_output_draining(Channel *c, fd_set * readset, fd_set * writeset) | |
737 | { | |
738 | if (buffer_len(&c->output) == 0) | |
739 | chan_mark_dead(c); | |
740 | else | |
741 | FD_SET(c->sock, writeset); | |
742 | } | |
743 | ||
744 | /* | |
745 | * This is a special state for X11 authentication spoofing. An opened X11 | |
746 | * connection (when authentication spoofing is being done) remains in this | |
747 | * state until the first packet has been completely read. The authentication | |
748 | * data in that packet is then substituted by the real data if it matches the | |
749 | * fake data, and the channel is put into normal mode. | |
750 | * XXX All this happens at the client side. | |
751 | * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok | |
752 | */ | |
753 | static int | |
754 | x11_open_helper(Buffer *b) | |
755 | { | |
756 | u_char *ucp; | |
757 | u_int proto_len, data_len; | |
758 | ||
759 | /* Check if the fixed size part of the packet is in buffer. */ | |
760 | if (buffer_len(b) < 12) | |
761 | return 0; | |
762 | ||
763 | /* Parse the lengths of variable-length fields. */ | |
1e608e42 | 764 | ucp = buffer_ptr(b); |
3c0ef626 | 765 | if (ucp[0] == 0x42) { /* Byte order MSB first. */ |
766 | proto_len = 256 * ucp[6] + ucp[7]; | |
767 | data_len = 256 * ucp[8] + ucp[9]; | |
768 | } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */ | |
769 | proto_len = ucp[6] + 256 * ucp[7]; | |
770 | data_len = ucp[8] + 256 * ucp[9]; | |
771 | } else { | |
772 | debug("Initial X11 packet contains bad byte order byte: 0x%x", | |
1e608e42 | 773 | ucp[0]); |
3c0ef626 | 774 | return -1; |
775 | } | |
776 | ||
777 | /* Check if the whole packet is in buffer. */ | |
778 | if (buffer_len(b) < | |
779 | 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3)) | |
780 | return 0; | |
781 | ||
782 | /* Check if authentication protocol matches. */ | |
783 | if (proto_len != strlen(x11_saved_proto) || | |
784 | memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) { | |
785 | debug("X11 connection uses different authentication protocol."); | |
786 | return -1; | |
787 | } | |
788 | /* Check if authentication data matches our fake data. */ | |
789 | if (data_len != x11_fake_data_len || | |
790 | memcmp(ucp + 12 + ((proto_len + 3) & ~3), | |
791 | x11_fake_data, x11_fake_data_len) != 0) { | |
792 | debug("X11 auth data does not match fake data."); | |
793 | return -1; | |
794 | } | |
795 | /* Check fake data length */ | |
796 | if (x11_fake_data_len != x11_saved_data_len) { | |
797 | error("X11 fake_data_len %d != saved_data_len %d", | |
798 | x11_fake_data_len, x11_saved_data_len); | |
799 | return -1; | |
800 | } | |
801 | /* | |
802 | * Received authentication protocol and data match | |
803 | * our fake data. Substitute the fake data with real | |
804 | * data. | |
805 | */ | |
806 | memcpy(ucp + 12 + ((proto_len + 3) & ~3), | |
807 | x11_saved_data, x11_saved_data_len); | |
808 | return 1; | |
809 | } | |
810 | ||
811 | static void | |
812 | channel_pre_x11_open_13(Channel *c, fd_set * readset, fd_set * writeset) | |
813 | { | |
814 | int ret = x11_open_helper(&c->output); | |
815 | if (ret == 1) { | |
816 | /* Start normal processing for the channel. */ | |
817 | c->type = SSH_CHANNEL_OPEN; | |
818 | channel_pre_open_13(c, readset, writeset); | |
819 | } else if (ret == -1) { | |
820 | /* | |
821 | * We have received an X11 connection that has bad | |
822 | * authentication information. | |
823 | */ | |
824 | log("X11 connection rejected because of wrong authentication."); | |
825 | buffer_clear(&c->input); | |
826 | buffer_clear(&c->output); | |
827 | channel_close_fd(&c->sock); | |
828 | c->sock = -1; | |
829 | c->type = SSH_CHANNEL_CLOSED; | |
830 | packet_start(SSH_MSG_CHANNEL_CLOSE); | |
831 | packet_put_int(c->remote_id); | |
832 | packet_send(); | |
833 | } | |
834 | } | |
835 | ||
836 | static void | |
837 | channel_pre_x11_open(Channel *c, fd_set * readset, fd_set * writeset) | |
838 | { | |
839 | int ret = x11_open_helper(&c->output); | |
840 | ||
841 | /* c->force_drain = 1; */ | |
842 | ||
843 | if (ret == 1) { | |
844 | c->type = SSH_CHANNEL_OPEN; | |
1e608e42 | 845 | channel_pre_open(c, readset, writeset); |
3c0ef626 | 846 | } else if (ret == -1) { |
1e608e42 | 847 | log("X11 connection rejected because of wrong authentication."); |
3c0ef626 | 848 | debug("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate); |
1e608e42 | 849 | chan_read_failed(c); |
850 | buffer_clear(&c->input); | |
851 | chan_ibuf_empty(c); | |
852 | buffer_clear(&c->output); | |
853 | /* for proto v1, the peer will send an IEOF */ | |
854 | if (compat20) | |
855 | chan_write_failed(c); | |
856 | else | |
857 | c->type = SSH_CHANNEL_OPEN; | |
3c0ef626 | 858 | debug("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate); |
859 | } | |
860 | } | |
861 | ||
862 | /* try to decode a socks4 header */ | |
863 | static int | |
864 | channel_decode_socks4(Channel *c, fd_set * readset, fd_set * writeset) | |
865 | { | |
866 | u_char *p, *host; | |
867 | int len, have, i, found; | |
1e608e42 | 868 | char username[256]; |
3c0ef626 | 869 | struct { |
870 | u_int8_t version; | |
871 | u_int8_t command; | |
872 | u_int16_t dest_port; | |
873 | struct in_addr dest_addr; | |
874 | } s4_req, s4_rsp; | |
875 | ||
876 | debug2("channel %d: decode socks4", c->self); | |
877 | ||
878 | have = buffer_len(&c->input); | |
879 | len = sizeof(s4_req); | |
880 | if (have < len) | |
881 | return 0; | |
882 | p = buffer_ptr(&c->input); | |
883 | for (found = 0, i = len; i < have; i++) { | |
884 | if (p[i] == '\0') { | |
885 | found = 1; | |
886 | break; | |
887 | } | |
888 | if (i > 1024) { | |
889 | /* the peer is probably sending garbage */ | |
890 | debug("channel %d: decode socks4: too long", | |
891 | c->self); | |
892 | return -1; | |
893 | } | |
894 | } | |
895 | if (!found) | |
896 | return 0; | |
897 | buffer_get(&c->input, (char *)&s4_req.version, 1); | |
898 | buffer_get(&c->input, (char *)&s4_req.command, 1); | |
899 | buffer_get(&c->input, (char *)&s4_req.dest_port, 2); | |
900 | buffer_get(&c->input, (char *)&s4_req.dest_addr, 4); | |
901 | have = buffer_len(&c->input); | |
902 | p = buffer_ptr(&c->input); | |
903 | len = strlen(p); | |
904 | debug2("channel %d: decode socks4: user %s/%d", c->self, p, len); | |
905 | if (len > have) | |
906 | fatal("channel %d: decode socks4: len %d > have %d", | |
907 | c->self, len, have); | |
908 | strlcpy(username, p, sizeof(username)); | |
909 | buffer_consume(&c->input, len); | |
910 | buffer_consume(&c->input, 1); /* trailing '\0' */ | |
911 | ||
912 | host = inet_ntoa(s4_req.dest_addr); | |
913 | strlcpy(c->path, host, sizeof(c->path)); | |
914 | c->host_port = ntohs(s4_req.dest_port); | |
1e608e42 | 915 | |
3c0ef626 | 916 | debug("channel %d: dynamic request: socks4 host %s port %u command %u", |
917 | c->self, host, c->host_port, s4_req.command); | |
918 | ||
919 | if (s4_req.command != 1) { | |
920 | debug("channel %d: cannot handle: socks4 cn %d", | |
921 | c->self, s4_req.command); | |
922 | return -1; | |
923 | } | |
924 | s4_rsp.version = 0; /* vn: 0 for reply */ | |
925 | s4_rsp.command = 90; /* cd: req granted */ | |
926 | s4_rsp.dest_port = 0; /* ignored */ | |
927 | s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */ | |
928 | buffer_append(&c->output, (char *)&s4_rsp, sizeof(s4_rsp)); | |
929 | return 1; | |
930 | } | |
931 | ||
932 | /* dynamic port forwarding */ | |
933 | static void | |
934 | channel_pre_dynamic(Channel *c, fd_set * readset, fd_set * writeset) | |
935 | { | |
936 | u_char *p; | |
937 | int have, ret; | |
938 | ||
939 | have = buffer_len(&c->input); | |
940 | c->delayed = 0; | |
941 | debug2("channel %d: pre_dynamic: have %d", c->self, have); | |
942 | /* buffer_dump(&c->input); */ | |
943 | /* check if the fixed size part of the packet is in buffer. */ | |
944 | if (have < 4) { | |
945 | /* need more */ | |
946 | FD_SET(c->sock, readset); | |
947 | return; | |
948 | } | |
949 | /* try to guess the protocol */ | |
950 | p = buffer_ptr(&c->input); | |
951 | switch (p[0]) { | |
952 | case 0x04: | |
953 | ret = channel_decode_socks4(c, readset, writeset); | |
954 | break; | |
955 | default: | |
956 | ret = -1; | |
957 | break; | |
958 | } | |
959 | if (ret < 0) { | |
960 | chan_mark_dead(c); | |
961 | } else if (ret == 0) { | |
962 | debug2("channel %d: pre_dynamic: need more", c->self); | |
963 | /* need more */ | |
964 | FD_SET(c->sock, readset); | |
965 | } else { | |
966 | /* switch to the next state */ | |
967 | c->type = SSH_CHANNEL_OPENING; | |
968 | port_open_helper(c, "direct-tcpip"); | |
969 | } | |
970 | } | |
971 | ||
972 | /* This is our fake X11 server socket. */ | |
973 | static void | |
974 | channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset) | |
975 | { | |
976 | Channel *nc; | |
977 | struct sockaddr addr; | |
978 | int newsock; | |
979 | socklen_t addrlen; | |
980 | char buf[16384], *remote_ipaddr; | |
981 | int remote_port; | |
982 | ||
983 | if (FD_ISSET(c->sock, readset)) { | |
984 | debug("X11 connection requested."); | |
985 | addrlen = sizeof(addr); | |
986 | newsock = accept(c->sock, &addr, &addrlen); | |
1e608e42 | 987 | if (c->single_connection) { |
988 | debug("single_connection: closing X11 listener."); | |
989 | channel_close_fd(&c->sock); | |
990 | chan_mark_dead(c); | |
991 | } | |
3c0ef626 | 992 | if (newsock < 0) { |
993 | error("accept: %.100s", strerror(errno)); | |
994 | return; | |
995 | } | |
1e608e42 | 996 | set_nodelay(newsock); |
3c0ef626 | 997 | remote_ipaddr = get_peer_ipaddr(newsock); |
998 | remote_port = get_peer_port(newsock); | |
999 | snprintf(buf, sizeof buf, "X11 connection from %.200s port %d", | |
1000 | remote_ipaddr, remote_port); | |
1001 | ||
1002 | nc = channel_new("accepted x11 socket", | |
1003 | SSH_CHANNEL_OPENING, newsock, newsock, -1, | |
1004 | c->local_window_max, c->local_maxpacket, | |
1005 | 0, xstrdup(buf), 1); | |
3c0ef626 | 1006 | if (compat20) { |
1007 | packet_start(SSH2_MSG_CHANNEL_OPEN); | |
1008 | packet_put_cstring("x11"); | |
1009 | packet_put_int(nc->self); | |
1e608e42 | 1010 | packet_put_int(nc->local_window_max); |
1011 | packet_put_int(nc->local_maxpacket); | |
3c0ef626 | 1012 | /* originator ipaddr and port */ |
1013 | packet_put_cstring(remote_ipaddr); | |
1014 | if (datafellows & SSH_BUG_X11FWD) { | |
1015 | debug("ssh2 x11 bug compat mode"); | |
1016 | } else { | |
1017 | packet_put_int(remote_port); | |
1018 | } | |
1019 | packet_send(); | |
1020 | } else { | |
1021 | packet_start(SSH_SMSG_X11_OPEN); | |
1022 | packet_put_int(nc->self); | |
1023 | if (packet_get_protocol_flags() & | |
1024 | SSH_PROTOFLAG_HOST_IN_FWD_OPEN) | |
1025 | packet_put_cstring(buf); | |
1026 | packet_send(); | |
1027 | } | |
1028 | xfree(remote_ipaddr); | |
1029 | } | |
1030 | } | |
1031 | ||
1032 | static void | |
1033 | port_open_helper(Channel *c, char *rtype) | |
1034 | { | |
1035 | int direct; | |
1036 | char buf[1024]; | |
1037 | char *remote_ipaddr = get_peer_ipaddr(c->sock); | |
1038 | u_short remote_port = get_peer_port(c->sock); | |
1039 | ||
1040 | direct = (strcmp(rtype, "direct-tcpip") == 0); | |
1041 | ||
1042 | snprintf(buf, sizeof buf, | |
1043 | "%s: listening port %d for %.100s port %d, " | |
1044 | "connect from %.200s port %d", | |
1045 | rtype, c->listening_port, c->path, c->host_port, | |
1046 | remote_ipaddr, remote_port); | |
1047 | ||
1048 | xfree(c->remote_name); | |
1049 | c->remote_name = xstrdup(buf); | |
1050 | ||
1051 | if (compat20) { | |
1052 | packet_start(SSH2_MSG_CHANNEL_OPEN); | |
1053 | packet_put_cstring(rtype); | |
1054 | packet_put_int(c->self); | |
1055 | packet_put_int(c->local_window_max); | |
1056 | packet_put_int(c->local_maxpacket); | |
1057 | if (direct) { | |
1058 | /* target host, port */ | |
1059 | packet_put_cstring(c->path); | |
1060 | packet_put_int(c->host_port); | |
1061 | } else { | |
1062 | /* listen address, port */ | |
1063 | packet_put_cstring(c->path); | |
1064 | packet_put_int(c->listening_port); | |
1065 | } | |
1066 | /* originator host and port */ | |
1067 | packet_put_cstring(remote_ipaddr); | |
1068 | packet_put_int(remote_port); | |
1069 | packet_send(); | |
1070 | } else { | |
1071 | packet_start(SSH_MSG_PORT_OPEN); | |
1072 | packet_put_int(c->self); | |
1073 | packet_put_cstring(c->path); | |
1074 | packet_put_int(c->host_port); | |
1075 | if (packet_get_protocol_flags() & | |
1076 | SSH_PROTOFLAG_HOST_IN_FWD_OPEN) | |
1077 | packet_put_cstring(c->remote_name); | |
1078 | packet_send(); | |
1079 | } | |
1080 | xfree(remote_ipaddr); | |
1081 | } | |
1082 | ||
1083 | /* | |
1084 | * This socket is listening for connections to a forwarded TCP/IP port. | |
1085 | */ | |
1086 | static void | |
1087 | channel_post_port_listener(Channel *c, fd_set * readset, fd_set * writeset) | |
1088 | { | |
1089 | Channel *nc; | |
1090 | struct sockaddr addr; | |
1091 | int newsock, nextstate; | |
1092 | socklen_t addrlen; | |
1093 | char *rtype; | |
1094 | ||
1095 | if (FD_ISSET(c->sock, readset)) { | |
1096 | debug("Connection to port %d forwarding " | |
1097 | "to %.100s port %d requested.", | |
1098 | c->listening_port, c->path, c->host_port); | |
1099 | ||
1100 | if (c->type == SSH_CHANNEL_RPORT_LISTENER) { | |
1101 | nextstate = SSH_CHANNEL_OPENING; | |
1102 | rtype = "forwarded-tcpip"; | |
1103 | } else { | |
1104 | if (c->host_port == 0) { | |
1105 | nextstate = SSH_CHANNEL_DYNAMIC; | |
1106 | rtype = "dynamic-tcpip"; | |
1107 | } else { | |
1108 | nextstate = SSH_CHANNEL_OPENING; | |
1109 | rtype = "direct-tcpip"; | |
1110 | } | |
1111 | } | |
1112 | ||
1113 | addrlen = sizeof(addr); | |
1114 | newsock = accept(c->sock, &addr, &addrlen); | |
1115 | if (newsock < 0) { | |
1116 | error("accept: %.100s", strerror(errno)); | |
1117 | return; | |
1118 | } | |
1e608e42 | 1119 | set_nodelay(newsock); |
3c0ef626 | 1120 | nc = channel_new(rtype, |
1121 | nextstate, newsock, newsock, -1, | |
1122 | c->local_window_max, c->local_maxpacket, | |
1123 | 0, xstrdup(rtype), 1); | |
3c0ef626 | 1124 | nc->listening_port = c->listening_port; |
1125 | nc->host_port = c->host_port; | |
1126 | strlcpy(nc->path, c->path, sizeof(nc->path)); | |
1127 | ||
1128 | if (nextstate == SSH_CHANNEL_DYNAMIC) { | |
1129 | /* | |
1130 | * do not call the channel_post handler until | |
1131 | * this flag has been reset by a pre-handler. | |
1132 | * otherwise the FD_ISSET calls might overflow | |
1133 | */ | |
1134 | nc->delayed = 1; | |
1135 | } else { | |
1136 | port_open_helper(nc, rtype); | |
1137 | } | |
1138 | } | |
1139 | } | |
1140 | ||
1141 | /* | |
1142 | * This is the authentication agent socket listening for connections from | |
1143 | * clients. | |
1144 | */ | |
1145 | static void | |
1146 | channel_post_auth_listener(Channel *c, fd_set * readset, fd_set * writeset) | |
1147 | { | |
1148 | Channel *nc; | |
1149 | char *name; | |
1150 | int newsock; | |
1151 | struct sockaddr addr; | |
1152 | socklen_t addrlen; | |
1153 | ||
1154 | if (FD_ISSET(c->sock, readset)) { | |
1155 | addrlen = sizeof(addr); | |
1156 | newsock = accept(c->sock, &addr, &addrlen); | |
1157 | if (newsock < 0) { | |
1158 | error("accept from auth socket: %.100s", strerror(errno)); | |
1159 | return; | |
1160 | } | |
1161 | name = xstrdup("accepted auth socket"); | |
1162 | nc = channel_new("accepted auth socket", | |
1163 | SSH_CHANNEL_OPENING, newsock, newsock, -1, | |
1164 | c->local_window_max, c->local_maxpacket, | |
1165 | 0, name, 1); | |
3c0ef626 | 1166 | if (compat20) { |
1167 | packet_start(SSH2_MSG_CHANNEL_OPEN); | |
1168 | packet_put_cstring("auth-agent@openssh.com"); | |
1169 | packet_put_int(nc->self); | |
1170 | packet_put_int(c->local_window_max); | |
1171 | packet_put_int(c->local_maxpacket); | |
1172 | } else { | |
1173 | packet_start(SSH_SMSG_AGENT_OPEN); | |
1174 | packet_put_int(nc->self); | |
1175 | } | |
1176 | packet_send(); | |
1177 | } | |
1178 | } | |
1179 | ||
1180 | static void | |
1181 | channel_post_connecting(Channel *c, fd_set * readset, fd_set * writeset) | |
1182 | { | |
1183 | int err = 0; | |
1184 | socklen_t sz = sizeof(err); | |
1185 | ||
1186 | if (FD_ISSET(c->sock, writeset)) { | |
1e608e42 | 1187 | if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) { |
3c0ef626 | 1188 | err = errno; |
1189 | error("getsockopt SO_ERROR failed"); | |
1190 | } | |
1191 | if (err == 0) { | |
1192 | debug("channel %d: connected", c->self); | |
1193 | c->type = SSH_CHANNEL_OPEN; | |
1194 | if (compat20) { | |
1195 | packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION); | |
1196 | packet_put_int(c->remote_id); | |
1197 | packet_put_int(c->self); | |
1198 | packet_put_int(c->local_window); | |
1199 | packet_put_int(c->local_maxpacket); | |
1200 | } else { | |
1201 | packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION); | |
1202 | packet_put_int(c->remote_id); | |
1203 | packet_put_int(c->self); | |
1204 | } | |
1205 | } else { | |
1206 | debug("channel %d: not connected: %s", | |
1207 | c->self, strerror(err)); | |
1208 | if (compat20) { | |
1209 | packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE); | |
1210 | packet_put_int(c->remote_id); | |
1211 | packet_put_int(SSH2_OPEN_CONNECT_FAILED); | |
1212 | if (!(datafellows & SSH_BUG_OPENFAILURE)) { | |
1213 | packet_put_cstring(strerror(err)); | |
1214 | packet_put_cstring(""); | |
1215 | } | |
1216 | } else { | |
1217 | packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); | |
1218 | packet_put_int(c->remote_id); | |
1219 | } | |
1220 | chan_mark_dead(c); | |
1221 | } | |
1222 | packet_send(); | |
1223 | } | |
1224 | } | |
1225 | ||
1226 | static int | |
1227 | channel_handle_rfd(Channel *c, fd_set * readset, fd_set * writeset) | |
1228 | { | |
1229 | char buf[16*1024]; | |
1230 | int len; | |
1231 | ||
1232 | if (c->rfd != -1 && | |
1233 | FD_ISSET(c->rfd, readset)) { | |
1234 | len = read(c->rfd, buf, sizeof(buf)); | |
1235 | if (len < 0 && (errno == EINTR || errno == EAGAIN)) | |
1236 | return 1; | |
1237 | if (len <= 0) { | |
1238 | debug("channel %d: read<=0 rfd %d len %d", | |
1239 | c->self, c->rfd, len); | |
1240 | if (c->type != SSH_CHANNEL_OPEN) { | |
1241 | debug("channel %d: not open", c->self); | |
1242 | chan_mark_dead(c); | |
1243 | return -1; | |
1244 | } else if (compat13) { | |
1e608e42 | 1245 | buffer_clear(&c->output); |
3c0ef626 | 1246 | c->type = SSH_CHANNEL_INPUT_DRAINING; |
1247 | debug("channel %d: input draining.", c->self); | |
1248 | } else { | |
1249 | chan_read_failed(c); | |
1250 | } | |
1251 | return -1; | |
1252 | } | |
1e608e42 | 1253 | if (c->input_filter != NULL) { |
3c0ef626 | 1254 | if (c->input_filter(c, buf, len) == -1) { |
1255 | debug("channel %d: filter stops", c->self); | |
1256 | chan_read_failed(c); | |
1257 | } | |
1258 | } else { | |
1259 | buffer_append(&c->input, buf, len); | |
1260 | } | |
1261 | } | |
1262 | return 1; | |
1263 | } | |
1264 | static int | |
1265 | channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset) | |
1266 | { | |
1267 | struct termios tio; | |
1268 | u_char *data; | |
1269 | u_int dlen; | |
1270 | int len; | |
1271 | ||
1272 | /* Send buffered output data to the socket. */ | |
1273 | if (c->wfd != -1 && | |
1274 | FD_ISSET(c->wfd, writeset) && | |
1275 | buffer_len(&c->output) > 0) { | |
1276 | data = buffer_ptr(&c->output); | |
1277 | dlen = buffer_len(&c->output); | |
1278 | len = write(c->wfd, data, dlen); | |
1279 | if (len < 0 && (errno == EINTR || errno == EAGAIN)) | |
1280 | return 1; | |
1281 | if (len <= 0) { | |
1282 | if (c->type != SSH_CHANNEL_OPEN) { | |
1283 | debug("channel %d: not open", c->self); | |
1284 | chan_mark_dead(c); | |
1285 | return -1; | |
1286 | } else if (compat13) { | |
1e608e42 | 1287 | buffer_clear(&c->output); |
3c0ef626 | 1288 | debug("channel %d: input draining.", c->self); |
1289 | c->type = SSH_CHANNEL_INPUT_DRAINING; | |
1290 | } else { | |
1291 | chan_write_failed(c); | |
1292 | } | |
1293 | return -1; | |
1294 | } | |
1295 | if (compat20 && c->isatty && dlen >= 1 && data[0] != '\r') { | |
1296 | if (tcgetattr(c->wfd, &tio) == 0 && | |
1297 | !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) { | |
1298 | /* | |
1299 | * Simulate echo to reduce the impact of | |
1300 | * traffic analysis. We need to match the | |
1301 | * size of a SSH2_MSG_CHANNEL_DATA message | |
1302 | * (4 byte channel id + data) | |
1303 | */ | |
1304 | packet_send_ignore(4 + len); | |
1305 | packet_send(); | |
1306 | } | |
1307 | } | |
1308 | buffer_consume(&c->output, len); | |
1309 | if (compat20 && len > 0) { | |
1310 | c->local_consumed += len; | |
1311 | } | |
1312 | } | |
1313 | return 1; | |
1314 | } | |
1315 | static int | |
1316 | channel_handle_efd(Channel *c, fd_set * readset, fd_set * writeset) | |
1317 | { | |
1318 | char buf[16*1024]; | |
1319 | int len; | |
1320 | ||
1321 | /** XXX handle drain efd, too */ | |
1322 | if (c->efd != -1) { | |
1323 | if (c->extended_usage == CHAN_EXTENDED_WRITE && | |
1324 | FD_ISSET(c->efd, writeset) && | |
1325 | buffer_len(&c->extended) > 0) { | |
1326 | len = write(c->efd, buffer_ptr(&c->extended), | |
1327 | buffer_len(&c->extended)); | |
1328 | debug2("channel %d: written %d to efd %d", | |
1329 | c->self, len, c->efd); | |
1330 | if (len < 0 && (errno == EINTR || errno == EAGAIN)) | |
1331 | return 1; | |
1332 | if (len <= 0) { | |
1333 | debug2("channel %d: closing write-efd %d", | |
1334 | c->self, c->efd); | |
1335 | channel_close_fd(&c->efd); | |
1336 | } else { | |
1337 | buffer_consume(&c->extended, len); | |
1338 | c->local_consumed += len; | |
1339 | } | |
1340 | } else if (c->extended_usage == CHAN_EXTENDED_READ && | |
1341 | FD_ISSET(c->efd, readset)) { | |
1342 | len = read(c->efd, buf, sizeof(buf)); | |
1343 | debug2("channel %d: read %d from efd %d", | |
1e608e42 | 1344 | c->self, len, c->efd); |
3c0ef626 | 1345 | if (len < 0 && (errno == EINTR || errno == EAGAIN)) |
1346 | return 1; | |
1347 | if (len <= 0) { | |
1348 | debug2("channel %d: closing read-efd %d", | |
1349 | c->self, c->efd); | |
1350 | channel_close_fd(&c->efd); | |
1351 | } else { | |
1352 | buffer_append(&c->extended, buf, len); | |
1353 | } | |
1354 | } | |
1355 | } | |
1356 | return 1; | |
1357 | } | |
1358 | static int | |
1359 | channel_check_window(Channel *c) | |
1360 | { | |
1361 | if (c->type == SSH_CHANNEL_OPEN && | |
1362 | !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) && | |
1363 | c->local_window < c->local_window_max/2 && | |
1364 | c->local_consumed > 0) { | |
1365 | packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST); | |
1366 | packet_put_int(c->remote_id); | |
1367 | packet_put_int(c->local_consumed); | |
1368 | packet_send(); | |
1369 | debug2("channel %d: window %d sent adjust %d", | |
1370 | c->self, c->local_window, | |
1371 | c->local_consumed); | |
1372 | c->local_window += c->local_consumed; | |
1373 | c->local_consumed = 0; | |
1374 | } | |
1375 | return 1; | |
1376 | } | |
1377 | ||
1378 | static void | |
1e608e42 | 1379 | channel_post_open(Channel *c, fd_set * readset, fd_set * writeset) |
3c0ef626 | 1380 | { |
1381 | if (c->delayed) | |
1382 | return; | |
1383 | channel_handle_rfd(c, readset, writeset); | |
1384 | channel_handle_wfd(c, readset, writeset); | |
1e608e42 | 1385 | if (!compat20) |
3c0ef626 | 1386 | return; |
3c0ef626 | 1387 | channel_handle_efd(c, readset, writeset); |
3c0ef626 | 1388 | channel_check_window(c); |
1389 | } | |
1390 | ||
1391 | static void | |
1392 | channel_post_output_drain_13(Channel *c, fd_set * readset, fd_set * writeset) | |
1393 | { | |
1394 | int len; | |
1395 | /* Send buffered output data to the socket. */ | |
1396 | if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) { | |
1397 | len = write(c->sock, buffer_ptr(&c->output), | |
1398 | buffer_len(&c->output)); | |
1399 | if (len <= 0) | |
1e608e42 | 1400 | buffer_clear(&c->output); |
3c0ef626 | 1401 | else |
1402 | buffer_consume(&c->output, len); | |
1403 | } | |
1404 | } | |
1405 | ||
1406 | static void | |
1407 | channel_handler_init_20(void) | |
1408 | { | |
1e608e42 | 1409 | channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open; |
3c0ef626 | 1410 | channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; |
1411 | channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; | |
1412 | channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener; | |
1413 | channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; | |
1414 | channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; | |
1415 | channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; | |
1416 | channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; | |
1417 | ||
1e608e42 | 1418 | channel_post[SSH_CHANNEL_OPEN] = &channel_post_open; |
3c0ef626 | 1419 | channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; |
1420 | channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener; | |
1421 | channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; | |
1422 | channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; | |
1423 | channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; | |
1e608e42 | 1424 | channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; |
3c0ef626 | 1425 | } |
1426 | ||
1427 | static void | |
1428 | channel_handler_init_13(void) | |
1429 | { | |
1430 | channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13; | |
1431 | channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13; | |
1432 | channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; | |
1433 | channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; | |
1434 | channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; | |
1435 | channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining; | |
1436 | channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining; | |
1437 | channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; | |
1438 | channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; | |
1439 | ||
1e608e42 | 1440 | channel_post[SSH_CHANNEL_OPEN] = &channel_post_open; |
3c0ef626 | 1441 | channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; |
1442 | channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; | |
1443 | channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; | |
1444 | channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13; | |
1445 | channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; | |
1e608e42 | 1446 | channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; |
3c0ef626 | 1447 | } |
1448 | ||
1449 | static void | |
1450 | channel_handler_init_15(void) | |
1451 | { | |
1e608e42 | 1452 | channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open; |
3c0ef626 | 1453 | channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; |
1454 | channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; | |
1455 | channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; | |
1456 | channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; | |
1457 | channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; | |
1458 | channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; | |
1459 | ||
1460 | channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; | |
1461 | channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; | |
1462 | channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; | |
1e608e42 | 1463 | channel_post[SSH_CHANNEL_OPEN] = &channel_post_open; |
3c0ef626 | 1464 | channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; |
1e608e42 | 1465 | channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; |
3c0ef626 | 1466 | } |
1467 | ||
1468 | static void | |
1469 | channel_handler_init(void) | |
1470 | { | |
1471 | int i; | |
1e608e42 | 1472 | for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) { |
3c0ef626 | 1473 | channel_pre[i] = NULL; |
1474 | channel_post[i] = NULL; | |
1475 | } | |
1476 | if (compat20) | |
1477 | channel_handler_init_20(); | |
1478 | else if (compat13) | |
1479 | channel_handler_init_13(); | |
1480 | else | |
1481 | channel_handler_init_15(); | |
1482 | } | |
1483 | ||
1484 | /* gc dead channels */ | |
1485 | static void | |
1486 | channel_garbage_collect(Channel *c) | |
1487 | { | |
1488 | if (c == NULL) | |
1489 | return; | |
1490 | if (c->detach_user != NULL) { | |
1491 | if (!chan_is_dead(c, 0)) | |
1492 | return; | |
1493 | debug("channel %d: gc: notify user", c->self); | |
1494 | c->detach_user(c->self, NULL); | |
1495 | /* if we still have a callback */ | |
1496 | if (c->detach_user != NULL) | |
1497 | return; | |
1498 | debug("channel %d: gc: user detached", c->self); | |
1499 | } | |
1500 | if (!chan_is_dead(c, 1)) | |
1501 | return; | |
1502 | debug("channel %d: garbage collecting", c->self); | |
1503 | channel_free(c); | |
1504 | } | |
1505 | ||
1506 | static void | |
1507 | channel_handler(chan_fn *ftab[], fd_set * readset, fd_set * writeset) | |
1508 | { | |
1509 | static int did_init = 0; | |
1510 | int i; | |
1511 | Channel *c; | |
1512 | ||
1513 | if (!did_init) { | |
1514 | channel_handler_init(); | |
1515 | did_init = 1; | |
1516 | } | |
1517 | for (i = 0; i < channels_alloc; i++) { | |
1518 | c = channels[i]; | |
1519 | if (c == NULL) | |
1520 | continue; | |
1521 | if (ftab[c->type] != NULL) | |
1522 | (*ftab[c->type])(c, readset, writeset); | |
1523 | channel_garbage_collect(c); | |
1524 | } | |
1525 | } | |
1526 | ||
1527 | /* | |
1528 | * Allocate/update select bitmasks and add any bits relevant to channels in | |
1529 | * select bitmasks. | |
1530 | */ | |
1531 | void | |
1532 | channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp, | |
1533 | int *nallocp, int rekeying) | |
1534 | { | |
1535 | int n; | |
1536 | u_int sz; | |
1537 | ||
1538 | n = MAX(*maxfdp, channel_max_fd); | |
1539 | ||
1540 | sz = howmany(n+1, NFDBITS) * sizeof(fd_mask); | |
1541 | /* perhaps check sz < nalloc/2 and shrink? */ | |
1542 | if (*readsetp == NULL || sz > *nallocp) { | |
1543 | *readsetp = xrealloc(*readsetp, sz); | |
1544 | *writesetp = xrealloc(*writesetp, sz); | |
1545 | *nallocp = sz; | |
1546 | } | |
1547 | *maxfdp = n; | |
1548 | memset(*readsetp, 0, sz); | |
1549 | memset(*writesetp, 0, sz); | |
1550 | ||
1551 | if (!rekeying) | |
1552 | channel_handler(channel_pre, *readsetp, *writesetp); | |
1553 | } | |
1554 | ||
1555 | /* | |
1556 | * After select, perform any appropriate operations for channels which have | |
1557 | * events pending. | |
1558 | */ | |
1559 | void | |
1560 | channel_after_select(fd_set * readset, fd_set * writeset) | |
1561 | { | |
1562 | channel_handler(channel_post, readset, writeset); | |
1563 | } | |
1564 | ||
1565 | ||
1566 | /* If there is data to send to the connection, enqueue some of it now. */ | |
1567 | ||
1568 | void | |
1e608e42 | 1569 | channel_output_poll(void) |
3c0ef626 | 1570 | { |
1571 | int len, i; | |
1572 | Channel *c; | |
1573 | ||
1574 | for (i = 0; i < channels_alloc; i++) { | |
1575 | c = channels[i]; | |
1576 | if (c == NULL) | |
1577 | continue; | |
1578 | ||
1579 | /* | |
1580 | * We are only interested in channels that can have buffered | |
1581 | * incoming data. | |
1582 | */ | |
1583 | if (compat13) { | |
1584 | if (c->type != SSH_CHANNEL_OPEN && | |
1585 | c->type != SSH_CHANNEL_INPUT_DRAINING) | |
1586 | continue; | |
1587 | } else { | |
1588 | if (c->type != SSH_CHANNEL_OPEN) | |
1589 | continue; | |
1590 | } | |
1591 | if (compat20 && | |
1592 | (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) { | |
1593 | /* XXX is this true? */ | |
1594 | debug3("channel %d: will not send data after close", c->self); | |
1595 | continue; | |
1596 | } | |
1597 | ||
1598 | /* Get the amount of buffered data for this channel. */ | |
1599 | if ((c->istate == CHAN_INPUT_OPEN || | |
1600 | c->istate == CHAN_INPUT_WAIT_DRAIN) && | |
1601 | (len = buffer_len(&c->input)) > 0) { | |
1602 | /* | |
1603 | * Send some data for the other side over the secure | |
1604 | * connection. | |
1605 | */ | |
1606 | if (compat20) { | |
1607 | if (len > c->remote_window) | |
1608 | len = c->remote_window; | |
1609 | if (len > c->remote_maxpacket) | |
1610 | len = c->remote_maxpacket; | |
1611 | } else { | |
1612 | if (packet_is_interactive()) { | |
1613 | if (len > 1024) | |
1614 | len = 512; | |
1615 | } else { | |
1616 | /* Keep the packets at reasonable size. */ | |
1617 | if (len > packet_get_maxsize()/2) | |
1618 | len = packet_get_maxsize()/2; | |
1619 | } | |
1620 | } | |
1621 | if (len > 0) { | |
1622 | packet_start(compat20 ? | |
1623 | SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA); | |
1624 | packet_put_int(c->remote_id); | |
1625 | packet_put_string(buffer_ptr(&c->input), len); | |
1626 | packet_send(); | |
1627 | buffer_consume(&c->input, len); | |
1628 | c->remote_window -= len; | |
1629 | } | |
1630 | } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) { | |
1631 | if (compat13) | |
1632 | fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3"); | |
1633 | /* | |
1634 | * input-buffer is empty and read-socket shutdown: | |
1635 | * tell peer, that we will not send more data: send IEOF | |
1636 | */ | |
1637 | chan_ibuf_empty(c); | |
1638 | } | |
1639 | /* Send extended data, i.e. stderr */ | |
1640 | if (compat20 && | |
1641 | c->remote_window > 0 && | |
1642 | (len = buffer_len(&c->extended)) > 0 && | |
1643 | c->extended_usage == CHAN_EXTENDED_READ) { | |
1644 | debug2("channel %d: rwin %d elen %d euse %d", | |
1645 | c->self, c->remote_window, buffer_len(&c->extended), | |
1646 | c->extended_usage); | |
1647 | if (len > c->remote_window) | |
1648 | len = c->remote_window; | |
1649 | if (len > c->remote_maxpacket) | |
1650 | len = c->remote_maxpacket; | |
1651 | packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA); | |
1652 | packet_put_int(c->remote_id); | |
1653 | packet_put_int(SSH2_EXTENDED_DATA_STDERR); | |
1654 | packet_put_string(buffer_ptr(&c->extended), len); | |
1655 | packet_send(); | |
1656 | buffer_consume(&c->extended, len); | |
1657 | c->remote_window -= len; | |
1658 | debug2("channel %d: sent ext data %d", c->self, len); | |
1659 | } | |
1660 | } | |
1661 | } | |
1662 | ||
1663 | ||
1664 | /* -- protocol input */ | |
1665 | ||
1666 | void | |
1e608e42 | 1667 | channel_input_data(int type, u_int32_t seq, void *ctxt) |
3c0ef626 | 1668 | { |
1669 | int id; | |
1670 | char *data; | |
1671 | u_int data_len; | |
1672 | Channel *c; | |
1673 | ||
1674 | /* Get the channel number and verify it. */ | |
1675 | id = packet_get_int(); | |
1676 | c = channel_lookup(id); | |
1677 | if (c == NULL) | |
1678 | packet_disconnect("Received data for nonexistent channel %d.", id); | |
1679 | ||
1680 | /* Ignore any data for non-open channels (might happen on close) */ | |
1681 | if (c->type != SSH_CHANNEL_OPEN && | |
1682 | c->type != SSH_CHANNEL_X11_OPEN) | |
1683 | return; | |
1684 | ||
1685 | /* same for protocol 1.5 if output end is no longer open */ | |
1686 | if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) | |
1687 | return; | |
1688 | ||
1689 | /* Get the data. */ | |
1690 | data = packet_get_string(&data_len); | |
3c0ef626 | 1691 | |
1e608e42 | 1692 | if (compat20) { |
3c0ef626 | 1693 | if (data_len > c->local_maxpacket) { |
1694 | log("channel %d: rcvd big packet %d, maxpack %d", | |
1695 | c->self, data_len, c->local_maxpacket); | |
1696 | } | |
1697 | if (data_len > c->local_window) { | |
1698 | log("channel %d: rcvd too much data %d, win %d", | |
1699 | c->self, data_len, c->local_window); | |
1700 | xfree(data); | |
1701 | return; | |
1702 | } | |
1703 | c->local_window -= data_len; | |
3c0ef626 | 1704 | } |
1e608e42 | 1705 | packet_check_eom(); |
3c0ef626 | 1706 | buffer_append(&c->output, data, data_len); |
1707 | xfree(data); | |
1708 | } | |
1709 | ||
1710 | void | |
1e608e42 | 1711 | channel_input_extended_data(int type, u_int32_t seq, void *ctxt) |
3c0ef626 | 1712 | { |
1713 | int id; | |
1714 | int tcode; | |
1715 | char *data; | |
1716 | u_int data_len; | |
1717 | Channel *c; | |
1718 | ||
1719 | /* Get the channel number and verify it. */ | |
1720 | id = packet_get_int(); | |
1721 | c = channel_lookup(id); | |
1722 | ||
1723 | if (c == NULL) | |
1724 | packet_disconnect("Received extended_data for bad channel %d.", id); | |
1725 | if (c->type != SSH_CHANNEL_OPEN) { | |
1726 | log("channel %d: ext data for non open", id); | |
1727 | return; | |
1728 | } | |
1729 | tcode = packet_get_int(); | |
1730 | if (c->efd == -1 || | |
1731 | c->extended_usage != CHAN_EXTENDED_WRITE || | |
1732 | tcode != SSH2_EXTENDED_DATA_STDERR) { | |
1733 | log("channel %d: bad ext data", c->self); | |
1734 | return; | |
1735 | } | |
1736 | data = packet_get_string(&data_len); | |
1e608e42 | 1737 | packet_check_eom(); |
3c0ef626 | 1738 | if (data_len > c->local_window) { |
1739 | log("channel %d: rcvd too much extended_data %d, win %d", | |
1740 | c->self, data_len, c->local_window); | |
1741 | xfree(data); | |
1742 | return; | |
1743 | } | |
1744 | debug2("channel %d: rcvd ext data %d", c->self, data_len); | |
1745 | c->local_window -= data_len; | |
1746 | buffer_append(&c->extended, data, data_len); | |
1747 | xfree(data); | |
1748 | } | |
1749 | ||
1750 | void | |
1e608e42 | 1751 | channel_input_ieof(int type, u_int32_t seq, void *ctxt) |
3c0ef626 | 1752 | { |
1753 | int id; | |
1754 | Channel *c; | |
1755 | ||
3c0ef626 | 1756 | id = packet_get_int(); |
1e608e42 | 1757 | packet_check_eom(); |
3c0ef626 | 1758 | c = channel_lookup(id); |
1759 | if (c == NULL) | |
1760 | packet_disconnect("Received ieof for nonexistent channel %d.", id); | |
1761 | chan_rcvd_ieof(c); | |
1762 | ||
1763 | /* XXX force input close */ | |
1e608e42 | 1764 | if (c->force_drain && c->istate == CHAN_INPUT_OPEN) { |
3c0ef626 | 1765 | debug("channel %d: FORCE input drain", c->self); |
1766 | c->istate = CHAN_INPUT_WAIT_DRAIN; | |
1e608e42 | 1767 | if (buffer_len(&c->input) == 0) |
1768 | chan_ibuf_empty(c); | |
3c0ef626 | 1769 | } |
1770 | ||
1771 | } | |
1772 | ||
1773 | void | |
1e608e42 | 1774 | channel_input_close(int type, u_int32_t seq, void *ctxt) |
3c0ef626 | 1775 | { |
1776 | int id; | |
1777 | Channel *c; | |
1778 | ||
3c0ef626 | 1779 | id = packet_get_int(); |
1e608e42 | 1780 | packet_check_eom(); |
3c0ef626 | 1781 | c = channel_lookup(id); |
1782 | if (c == NULL) | |
1783 | packet_disconnect("Received close for nonexistent channel %d.", id); | |
1784 | ||
1785 | /* | |
1786 | * Send a confirmation that we have closed the channel and no more | |
1787 | * data is coming for it. | |
1788 | */ | |
1789 | packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION); | |
1790 | packet_put_int(c->remote_id); | |
1791 | packet_send(); | |
1792 | ||
1793 | /* | |
1794 | * If the channel is in closed state, we have sent a close request, | |
1795 | * and the other side will eventually respond with a confirmation. | |
1796 | * Thus, we cannot free the channel here, because then there would be | |
1797 | * no-one to receive the confirmation. The channel gets freed when | |
1798 | * the confirmation arrives. | |
1799 | */ | |
1800 | if (c->type != SSH_CHANNEL_CLOSED) { | |
1801 | /* | |
1802 | * Not a closed channel - mark it as draining, which will | |
1803 | * cause it to be freed later. | |
1804 | */ | |
1e608e42 | 1805 | buffer_clear(&c->input); |
3c0ef626 | 1806 | c->type = SSH_CHANNEL_OUTPUT_DRAINING; |
1807 | } | |
1808 | } | |
1809 | ||
1810 | /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */ | |
1811 | void | |
1e608e42 | 1812 | channel_input_oclose(int type, u_int32_t seq, void *ctxt) |
3c0ef626 | 1813 | { |
1814 | int id = packet_get_int(); | |
1815 | Channel *c = channel_lookup(id); | |
1e608e42 | 1816 | |
1817 | packet_check_eom(); | |
3c0ef626 | 1818 | if (c == NULL) |
1819 | packet_disconnect("Received oclose for nonexistent channel %d.", id); | |
1820 | chan_rcvd_oclose(c); | |
1821 | } | |
1822 | ||
1823 | void | |
1e608e42 | 1824 | channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt) |
3c0ef626 | 1825 | { |
1826 | int id = packet_get_int(); | |
1827 | Channel *c = channel_lookup(id); | |
1828 | ||
1e608e42 | 1829 | packet_check_eom(); |
3c0ef626 | 1830 | if (c == NULL) |
1831 | packet_disconnect("Received close confirmation for " | |
1832 | "out-of-range channel %d.", id); | |
1833 | if (c->type != SSH_CHANNEL_CLOSED) | |
1834 | packet_disconnect("Received close confirmation for " | |
1835 | "non-closed channel %d (type %d).", id, c->type); | |
1836 | channel_free(c); | |
1837 | } | |
1838 | ||
1839 | void | |
1e608e42 | 1840 | channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt) |
3c0ef626 | 1841 | { |
1842 | int id, remote_id; | |
1843 | Channel *c; | |
1844 | ||
3c0ef626 | 1845 | id = packet_get_int(); |
1846 | c = channel_lookup(id); | |
1847 | ||
1848 | if (c==NULL || c->type != SSH_CHANNEL_OPENING) | |
1849 | packet_disconnect("Received open confirmation for " | |
1850 | "non-opening channel %d.", id); | |
1851 | remote_id = packet_get_int(); | |
1852 | /* Record the remote channel number and mark that the channel is now open. */ | |
1853 | c->remote_id = remote_id; | |
1854 | c->type = SSH_CHANNEL_OPEN; | |
1855 | ||
1856 | if (compat20) { | |
1857 | c->remote_window = packet_get_int(); | |
1858 | c->remote_maxpacket = packet_get_int(); | |
1e608e42 | 1859 | if (c->confirm) { |
3c0ef626 | 1860 | debug2("callback start"); |
1e608e42 | 1861 | c->confirm(c->self, NULL); |
3c0ef626 | 1862 | debug2("callback done"); |
1863 | } | |
1864 | debug("channel %d: open confirm rwindow %d rmax %d", c->self, | |
1865 | c->remote_window, c->remote_maxpacket); | |
1866 | } | |
1e608e42 | 1867 | packet_check_eom(); |
3c0ef626 | 1868 | } |
1869 | ||
1870 | static char * | |
1871 | reason2txt(int reason) | |
1872 | { | |
1e608e42 | 1873 | switch (reason) { |
3c0ef626 | 1874 | case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED: |
1875 | return "administratively prohibited"; | |
1876 | case SSH2_OPEN_CONNECT_FAILED: | |
1877 | return "connect failed"; | |
1878 | case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE: | |
1879 | return "unknown channel type"; | |
1880 | case SSH2_OPEN_RESOURCE_SHORTAGE: | |
1881 | return "resource shortage"; | |
1882 | } | |
1883 | return "unknown reason"; | |
1884 | } | |
1885 | ||
1886 | void | |
1e608e42 | 1887 | channel_input_open_failure(int type, u_int32_t seq, void *ctxt) |
3c0ef626 | 1888 | { |
1889 | int id, reason; | |
1890 | char *msg = NULL, *lang = NULL; | |
1891 | Channel *c; | |
1892 | ||
3c0ef626 | 1893 | id = packet_get_int(); |
1894 | c = channel_lookup(id); | |
1895 | ||
1896 | if (c==NULL || c->type != SSH_CHANNEL_OPENING) | |
1897 | packet_disconnect("Received open failure for " | |
1898 | "non-opening channel %d.", id); | |
1899 | if (compat20) { | |
1900 | reason = packet_get_int(); | |
1901 | if (!(datafellows & SSH_BUG_OPENFAILURE)) { | |
1902 | msg = packet_get_string(NULL); | |
1903 | lang = packet_get_string(NULL); | |
1904 | } | |
3c0ef626 | 1905 | log("channel %d: open failed: %s%s%s", id, |
1906 | reason2txt(reason), msg ? ": ": "", msg ? msg : ""); | |
1907 | if (msg != NULL) | |
1908 | xfree(msg); | |
1909 | if (lang != NULL) | |
1910 | xfree(lang); | |
1911 | } | |
1e608e42 | 1912 | packet_check_eom(); |
3c0ef626 | 1913 | /* Free the channel. This will also close the socket. */ |
1914 | channel_free(c); | |
1915 | } | |
1916 | ||
1917 | void | |
1e608e42 | 1918 | channel_input_window_adjust(int type, u_int32_t seq, void *ctxt) |
3c0ef626 | 1919 | { |
1920 | Channel *c; | |
1921 | int id, adjust; | |
1922 | ||
1923 | if (!compat20) | |
1924 | return; | |
1925 | ||
1926 | /* Get the channel number and verify it. */ | |
1927 | id = packet_get_int(); | |
1928 | c = channel_lookup(id); | |
1929 | ||
1930 | if (c == NULL || c->type != SSH_CHANNEL_OPEN) { | |
1931 | log("Received window adjust for " | |
1932 | "non-open channel %d.", id); | |
1933 | return; | |
1934 | } | |
1935 | adjust = packet_get_int(); | |
1e608e42 | 1936 | packet_check_eom(); |
3c0ef626 | 1937 | debug2("channel %d: rcvd adjust %d", id, adjust); |
1938 | c->remote_window += adjust; | |
1939 | } | |
1940 | ||
1941 | void | |
1e608e42 | 1942 | channel_input_port_open(int type, u_int32_t seq, void *ctxt) |
3c0ef626 | 1943 | { |
1944 | Channel *c = NULL; | |
1945 | u_short host_port; | |
1946 | char *host, *originator_string; | |
1947 | int remote_id, sock = -1; | |
1948 | ||
1949 | remote_id = packet_get_int(); | |
1950 | host = packet_get_string(NULL); | |
1951 | host_port = packet_get_int(); | |
1952 | ||
1953 | if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) { | |
1954 | originator_string = packet_get_string(NULL); | |
1955 | } else { | |
1956 | originator_string = xstrdup("unknown (remote did not supply name)"); | |
1957 | } | |
1e608e42 | 1958 | packet_check_eom(); |
3c0ef626 | 1959 | sock = channel_connect_to(host, host_port); |
1960 | if (sock != -1) { | |
1961 | c = channel_new("connected socket", | |
1962 | SSH_CHANNEL_CONNECTING, sock, sock, -1, 0, 0, 0, | |
1963 | originator_string, 1); | |
1e608e42 | 1964 | c->remote_id = remote_id; |
3c0ef626 | 1965 | } |
1966 | if (c == NULL) { | |
1967 | packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); | |
1968 | packet_put_int(remote_id); | |
1969 | packet_send(); | |
1970 | } | |
1971 | xfree(host); | |
1972 | } | |
1973 | ||
1974 | ||
1975 | /* -- tcp forwarding */ | |
1976 | ||
1977 | void | |
1978 | channel_set_af(int af) | |
1979 | { | |
1980 | IPv4or6 = af; | |
1981 | } | |
1982 | ||
1e608e42 | 1983 | static int |
1984 | channel_setup_fwd_listener(int type, const char *listen_addr, u_short listen_port, | |
1985 | const char *host_to_connect, u_short port_to_connect, int gateway_ports) | |
3c0ef626 | 1986 | { |
1987 | Channel *c; | |
1e608e42 | 1988 | int success, sock, on = 1; |
3c0ef626 | 1989 | struct addrinfo hints, *ai, *aitop; |
3c0ef626 | 1990 | const char *host; |
1e608e42 | 1991 | char ntop[NI_MAXHOST], strport[NI_MAXSERV]; |
3c0ef626 | 1992 | struct linger linger; |
1993 | ||
1994 | success = 0; | |
1e608e42 | 1995 | host = (type == SSH_CHANNEL_RPORT_LISTENER) ? |
1996 | listen_addr : host_to_connect; | |
3c0ef626 | 1997 | |
1e608e42 | 1998 | if (host == NULL) { |
1999 | error("No forward host name."); | |
2000 | return success; | |
3c0ef626 | 2001 | } |
3c0ef626 | 2002 | if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) { |
2003 | error("Forward host name too long."); | |
2004 | return success; | |
2005 | } | |
2006 | ||
3c0ef626 | 2007 | /* |
2008 | * getaddrinfo returns a loopback address if the hostname is | |
2009 | * set to NULL and hints.ai_flags is not AI_PASSIVE | |
2010 | */ | |
2011 | memset(&hints, 0, sizeof(hints)); | |
2012 | hints.ai_family = IPv4or6; | |
2013 | hints.ai_flags = gateway_ports ? AI_PASSIVE : 0; | |
2014 | hints.ai_socktype = SOCK_STREAM; | |
2015 | snprintf(strport, sizeof strport, "%d", listen_port); | |
2016 | if (getaddrinfo(NULL, strport, &hints, &aitop) != 0) | |
2017 | packet_disconnect("getaddrinfo: fatal error"); | |
2018 | ||
2019 | for (ai = aitop; ai; ai = ai->ai_next) { | |
2020 | if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) | |
2021 | continue; | |
2022 | if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), | |
2023 | strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) { | |
1e608e42 | 2024 | error("channel_setup_fwd_listener: getnameinfo failed"); |
3c0ef626 | 2025 | continue; |
2026 | } | |
2027 | /* Create a port to listen for the host. */ | |
2028 | sock = socket(ai->ai_family, SOCK_STREAM, 0); | |
2029 | if (sock < 0) { | |
2030 | /* this is no error since kernel may not support ipv6 */ | |
2031 | verbose("socket: %.100s", strerror(errno)); | |
2032 | continue; | |
2033 | } | |
2034 | /* | |
2035 | * Set socket options. We would like the socket to disappear | |
2036 | * as soon as it has been closed for whatever reason. | |
2037 | */ | |
1e608e42 | 2038 | setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)); |
3c0ef626 | 2039 | linger.l_onoff = 1; |
2040 | linger.l_linger = 5; | |
1e608e42 | 2041 | setsockopt(sock, SOL_SOCKET, SO_LINGER, &linger, sizeof(linger)); |
3c0ef626 | 2042 | debug("Local forwarding listening on %s port %s.", ntop, strport); |
2043 | ||
2044 | /* Bind the socket to the address. */ | |
2045 | if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) { | |
2046 | /* address can be in use ipv6 address is already bound */ | |
2047 | if (!ai->ai_next) | |
2048 | error("bind: %.100s", strerror(errno)); | |
2049 | else | |
2050 | verbose("bind: %.100s", strerror(errno)); | |
2051 | ||
2052 | close(sock); | |
2053 | continue; | |
2054 | } | |
2055 | /* Start listening for connections on the socket. */ | |
2056 | if (listen(sock, 5) < 0) { | |
2057 | error("listen: %.100s", strerror(errno)); | |
2058 | close(sock); | |
2059 | continue; | |
2060 | } | |
2061 | /* Allocate a channel number for the socket. */ | |
2062 | c = channel_new("port listener", type, sock, sock, -1, | |
2063 | CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, | |
2064 | 0, xstrdup("port listener"), 1); | |
3c0ef626 | 2065 | strlcpy(c->path, host, sizeof(c->path)); |
2066 | c->host_port = port_to_connect; | |
2067 | c->listening_port = listen_port; | |
2068 | success = 1; | |
2069 | } | |
2070 | if (success == 0) | |
1e608e42 | 2071 | error("channel_setup_fwd_listener: cannot listen to port: %d", |
3c0ef626 | 2072 | listen_port); |
2073 | freeaddrinfo(aitop); | |
2074 | return success; | |
2075 | } | |
2076 | ||
1e608e42 | 2077 | /* protocol local port fwd, used by ssh (and sshd in v1) */ |
2078 | int | |
2079 | channel_setup_local_fwd_listener(u_short listen_port, | |
2080 | const char *host_to_connect, u_short port_to_connect, int gateway_ports) | |
2081 | { | |
2082 | return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER, | |
2083 | NULL, listen_port, host_to_connect, port_to_connect, gateway_ports); | |
2084 | } | |
2085 | ||
2086 | /* protocol v2 remote port fwd, used by sshd */ | |
2087 | int | |
2088 | channel_setup_remote_fwd_listener(const char *listen_address, | |
2089 | u_short listen_port, int gateway_ports) | |
2090 | { | |
2091 | return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER, | |
2092 | listen_address, listen_port, NULL, 0, gateway_ports); | |
2093 | } | |
2094 | ||
3c0ef626 | 2095 | /* |
2096 | * Initiate forwarding of connections to port "port" on remote host through | |
2097 | * the secure channel to host:port from local side. | |
2098 | */ | |
2099 | ||
2100 | void | |
2101 | channel_request_remote_forwarding(u_short listen_port, | |
2102 | const char *host_to_connect, u_short port_to_connect) | |
2103 | { | |
1e608e42 | 2104 | int type, success = 0; |
3c0ef626 | 2105 | |
2106 | /* Record locally that connection to this host/port is permitted. */ | |
2107 | if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION) | |
2108 | fatal("channel_request_remote_forwarding: too many forwards"); | |
2109 | ||
2110 | /* Send the forward request to the remote side. */ | |
2111 | if (compat20) { | |
2112 | const char *address_to_bind = "0.0.0.0"; | |
2113 | packet_start(SSH2_MSG_GLOBAL_REQUEST); | |
2114 | packet_put_cstring("tcpip-forward"); | |
2115 | packet_put_char(0); /* boolean: want reply */ | |
2116 | packet_put_cstring(address_to_bind); | |
2117 | packet_put_int(listen_port); | |
2118 | packet_send(); | |
2119 | packet_write_wait(); | |
2120 | /* Assume that server accepts the request */ | |
2121 | success = 1; | |
2122 | } else { | |
2123 | packet_start(SSH_CMSG_PORT_FORWARD_REQUEST); | |
2124 | packet_put_int(listen_port); | |
2125 | packet_put_cstring(host_to_connect); | |
2126 | packet_put_int(port_to_connect); | |
2127 | packet_send(); | |
2128 | packet_write_wait(); | |
2129 | ||
2130 | /* Wait for response from the remote side. */ | |
1e608e42 | 2131 | type = packet_read(); |
3c0ef626 | 2132 | switch (type) { |
2133 | case SSH_SMSG_SUCCESS: | |
2134 | success = 1; | |
2135 | break; | |
2136 | case SSH_SMSG_FAILURE: | |
2137 | log("Warning: Server denied remote port forwarding."); | |
2138 | break; | |
2139 | default: | |
2140 | /* Unknown packet */ | |
2141 | packet_disconnect("Protocol error for port forward request:" | |
2142 | "received packet type %d.", type); | |
2143 | } | |
2144 | } | |
2145 | if (success) { | |
2146 | permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect); | |
2147 | permitted_opens[num_permitted_opens].port_to_connect = port_to_connect; | |
2148 | permitted_opens[num_permitted_opens].listen_port = listen_port; | |
2149 | num_permitted_opens++; | |
2150 | } | |
2151 | } | |
2152 | ||
2153 | /* | |
2154 | * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates | |
2155 | * listening for the port, and sends back a success reply (or disconnect | |
2156 | * message if there was an error). This never returns if there was an error. | |
2157 | */ | |
2158 | ||
2159 | void | |
2160 | channel_input_port_forward_request(int is_root, int gateway_ports) | |
2161 | { | |
2162 | u_short port, host_port; | |
2163 | char *hostname; | |
2164 | ||
2165 | /* Get arguments from the packet. */ | |
2166 | port = packet_get_int(); | |
2167 | hostname = packet_get_string(NULL); | |
2168 | host_port = packet_get_int(); | |
2169 | ||
2170 | #ifndef HAVE_CYGWIN | |
2171 | /* | |
2172 | * Check that an unprivileged user is not trying to forward a | |
2173 | * privileged port. | |
2174 | */ | |
2175 | if (port < IPPORT_RESERVED && !is_root) | |
2176 | packet_disconnect("Requested forwarding of port %d but user is not root.", | |
2177 | port); | |
2178 | #endif | |
2179 | /* Initiate forwarding */ | |
1e608e42 | 2180 | channel_setup_local_fwd_listener(port, hostname, host_port, gateway_ports); |
3c0ef626 | 2181 | |
2182 | /* Free the argument string. */ | |
2183 | xfree(hostname); | |
2184 | } | |
2185 | ||
2186 | /* | |
2187 | * Permits opening to any host/port if permitted_opens[] is empty. This is | |
2188 | * usually called by the server, because the user could connect to any port | |
2189 | * anyway, and the server has no way to know but to trust the client anyway. | |
2190 | */ | |
2191 | void | |
1e608e42 | 2192 | channel_permit_all_opens(void) |
3c0ef626 | 2193 | { |
2194 | if (num_permitted_opens == 0) | |
2195 | all_opens_permitted = 1; | |
2196 | } | |
2197 | ||
2198 | void | |
2199 | channel_add_permitted_opens(char *host, int port) | |
2200 | { | |
2201 | if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION) | |
2202 | fatal("channel_request_remote_forwarding: too many forwards"); | |
2203 | debug("allow port forwarding to host %s port %d", host, port); | |
2204 | ||
2205 | permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host); | |
2206 | permitted_opens[num_permitted_opens].port_to_connect = port; | |
2207 | num_permitted_opens++; | |
2208 | ||
2209 | all_opens_permitted = 0; | |
2210 | } | |
2211 | ||
2212 | void | |
2213 | channel_clear_permitted_opens(void) | |
2214 | { | |
2215 | int i; | |
2216 | ||
2217 | for (i = 0; i < num_permitted_opens; i++) | |
2218 | xfree(permitted_opens[i].host_to_connect); | |
2219 | num_permitted_opens = 0; | |
2220 | ||
2221 | } | |
2222 | ||
2223 | ||
2224 | /* return socket to remote host, port */ | |
2225 | static int | |
2226 | connect_to(const char *host, u_short port) | |
2227 | { | |
2228 | struct addrinfo hints, *ai, *aitop; | |
2229 | char ntop[NI_MAXHOST], strport[NI_MAXSERV]; | |
2230 | int gaierr; | |
2231 | int sock = -1; | |
2232 | ||
2233 | memset(&hints, 0, sizeof(hints)); | |
2234 | hints.ai_family = IPv4or6; | |
2235 | hints.ai_socktype = SOCK_STREAM; | |
2236 | snprintf(strport, sizeof strport, "%d", port); | |
2237 | if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) { | |
2238 | error("connect_to %.100s: unknown host (%s)", host, | |
2239 | gai_strerror(gaierr)); | |
2240 | return -1; | |
2241 | } | |
2242 | for (ai = aitop; ai; ai = ai->ai_next) { | |
2243 | if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) | |
2244 | continue; | |
2245 | if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), | |
2246 | strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) { | |
2247 | error("connect_to: getnameinfo failed"); | |
2248 | continue; | |
2249 | } | |
2250 | sock = socket(ai->ai_family, SOCK_STREAM, 0); | |
2251 | if (sock < 0) { | |
2252 | error("socket: %.100s", strerror(errno)); | |
2253 | continue; | |
2254 | } | |
2255 | if (fcntl(sock, F_SETFL, O_NONBLOCK) < 0) | |
2256 | fatal("connect_to: F_SETFL: %s", strerror(errno)); | |
2257 | if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 && | |
2258 | errno != EINPROGRESS) { | |
2259 | error("connect_to %.100s port %s: %.100s", ntop, strport, | |
2260 | strerror(errno)); | |
2261 | close(sock); | |
2262 | continue; /* fail -- try next */ | |
2263 | } | |
2264 | break; /* success */ | |
2265 | ||
2266 | } | |
2267 | freeaddrinfo(aitop); | |
2268 | if (!ai) { | |
2269 | error("connect_to %.100s port %d: failed.", host, port); | |
2270 | return -1; | |
2271 | } | |
2272 | /* success */ | |
1e608e42 | 2273 | set_nodelay(sock); |
3c0ef626 | 2274 | return sock; |
2275 | } | |
2276 | ||
2277 | int | |
2278 | channel_connect_by_listen_address(u_short listen_port) | |
2279 | { | |
2280 | int i; | |
2281 | ||
2282 | for (i = 0; i < num_permitted_opens; i++) | |
2283 | if (permitted_opens[i].listen_port == listen_port) | |
2284 | return connect_to( | |
2285 | permitted_opens[i].host_to_connect, | |
2286 | permitted_opens[i].port_to_connect); | |
2287 | error("WARNING: Server requests forwarding for unknown listen_port %d", | |
2288 | listen_port); | |
2289 | return -1; | |
2290 | } | |
2291 | ||
2292 | /* Check if connecting to that port is permitted and connect. */ | |
2293 | int | |
2294 | channel_connect_to(const char *host, u_short port) | |
2295 | { | |
2296 | int i, permit; | |
2297 | ||
2298 | permit = all_opens_permitted; | |
2299 | if (!permit) { | |
2300 | for (i = 0; i < num_permitted_opens; i++) | |
2301 | if (permitted_opens[i].port_to_connect == port && | |
2302 | strcmp(permitted_opens[i].host_to_connect, host) == 0) | |
2303 | permit = 1; | |
2304 | ||
2305 | } | |
2306 | if (!permit) { | |
2307 | log("Received request to connect to host %.100s port %d, " | |
2308 | "but the request was denied.", host, port); | |
2309 | return -1; | |
2310 | } | |
2311 | return connect_to(host, port); | |
2312 | } | |
2313 | ||
2314 | /* -- X11 forwarding */ | |
2315 | ||
2316 | /* | |
2317 | * Creates an internet domain socket for listening for X11 connections. | |
1e608e42 | 2318 | * Returns a suitable display number for the DISPLAY variable, or -1 if |
2319 | * an error occurs. | |
3c0ef626 | 2320 | */ |
1e608e42 | 2321 | int |
2322 | x11_create_display_inet(int x11_display_offset, int x11_use_localhost, | |
2323 | int single_connection) | |
3c0ef626 | 2324 | { |
1e608e42 | 2325 | Channel *nc = NULL; |
3c0ef626 | 2326 | int display_number, sock; |
2327 | u_short port; | |
2328 | struct addrinfo hints, *ai, *aitop; | |
2329 | char strport[NI_MAXSERV]; | |
2330 | int gaierr, n, num_socks = 0, socks[NUM_SOCKS]; | |
3c0ef626 | 2331 | |
2332 | for (display_number = x11_display_offset; | |
1e608e42 | 2333 | display_number < MAX_DISPLAYS; |
2334 | display_number++) { | |
3c0ef626 | 2335 | port = 6000 + display_number; |
2336 | memset(&hints, 0, sizeof(hints)); | |
2337 | hints.ai_family = IPv4or6; | |
1e608e42 | 2338 | hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE; |
3c0ef626 | 2339 | hints.ai_socktype = SOCK_STREAM; |
2340 | snprintf(strport, sizeof strport, "%d", port); | |
2341 | if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) { | |
2342 | error("getaddrinfo: %.100s", gai_strerror(gaierr)); | |
1e608e42 | 2343 | return -1; |
3c0ef626 | 2344 | } |
2345 | for (ai = aitop; ai; ai = ai->ai_next) { | |
2346 | if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) | |
2347 | continue; | |
2348 | sock = socket(ai->ai_family, SOCK_STREAM, 0); | |
2349 | if (sock < 0) { | |
2350 | if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) { | |
2351 | error("socket: %.100s", strerror(errno)); | |
1e608e42 | 2352 | return -1; |
3c0ef626 | 2353 | } else { |
2354 | debug("x11_create_display_inet: Socket family %d not supported", | |
2355 | ai->ai_family); | |
2356 | continue; | |
2357 | } | |
2358 | } | |
2359 | if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) { | |
2360 | debug("bind port %d: %.100s", port, strerror(errno)); | |
3c0ef626 | 2361 | close(sock); |
2362 | ||
2363 | if (ai->ai_next) | |
2364 | continue; | |
2365 | ||
2366 | for (n = 0; n < num_socks; n++) { | |
3c0ef626 | 2367 | close(socks[n]); |
2368 | } | |
2369 | num_socks = 0; | |
2370 | break; | |
2371 | } | |
2372 | socks[num_socks++] = sock; | |
2373 | #ifndef DONT_TRY_OTHER_AF | |
2374 | if (num_socks == NUM_SOCKS) | |
2375 | break; | |
2376 | #else | |
2377 | break; | |
2378 | #endif | |
2379 | } | |
2380 | freeaddrinfo(aitop); | |
2381 | if (num_socks > 0) | |
2382 | break; | |
2383 | } | |
2384 | if (display_number >= MAX_DISPLAYS) { | |
2385 | error("Failed to allocate internet-domain X11 display socket."); | |
1e608e42 | 2386 | return -1; |
3c0ef626 | 2387 | } |
2388 | /* Start listening for connections on the socket. */ | |
2389 | for (n = 0; n < num_socks; n++) { | |
2390 | sock = socks[n]; | |
2391 | if (listen(sock, 5) < 0) { | |
2392 | error("listen: %.100s", strerror(errno)); | |
3c0ef626 | 2393 | close(sock); |
1e608e42 | 2394 | return -1; |
3c0ef626 | 2395 | } |
3c0ef626 | 2396 | } |
3c0ef626 | 2397 | |
2398 | /* Allocate a channel for each socket. */ | |
2399 | for (n = 0; n < num_socks; n++) { | |
2400 | sock = socks[n]; | |
1e608e42 | 2401 | nc = channel_new("x11 listener", |
3c0ef626 | 2402 | SSH_CHANNEL_X11_LISTENER, sock, sock, -1, |
2403 | CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, | |
2404 | 0, xstrdup("X11 inet listener"), 1); | |
1e608e42 | 2405 | nc->single_connection = single_connection; |
3c0ef626 | 2406 | } |
2407 | ||
1e608e42 | 2408 | /* Return the display number for the DISPLAY environment variable. */ |
2409 | return display_number; | |
3c0ef626 | 2410 | } |
2411 | ||
3c0ef626 | 2412 | static int |
2413 | connect_local_xsocket(u_int dnr) | |
2414 | { | |
3c0ef626 | 2415 | int sock; |
2416 | struct sockaddr_un addr; | |
3c0ef626 | 2417 | |
1e608e42 | 2418 | sock = socket(AF_UNIX, SOCK_STREAM, 0); |
2419 | if (sock < 0) | |
2420 | error("socket: %.100s", strerror(errno)); | |
2421 | memset(&addr, 0, sizeof(addr)); | |
2422 | addr.sun_family = AF_UNIX; | |
2423 | snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr); | |
2424 | if (connect(sock, (struct sockaddr *) & addr, sizeof(addr)) == 0) | |
2425 | return sock; | |
2426 | close(sock); | |
3c0ef626 | 2427 | error("connect %.100s: %.100s", addr.sun_path, strerror(errno)); |
2428 | return -1; | |
2429 | } | |
2430 | ||
2431 | int | |
2432 | x11_connect_display(void) | |
2433 | { | |
2434 | int display_number, sock = 0; | |
2435 | const char *display; | |
2436 | char buf[1024], *cp; | |
2437 | struct addrinfo hints, *ai, *aitop; | |
2438 | char strport[NI_MAXSERV]; | |
2439 | int gaierr; | |
2440 | ||
2441 | /* Try to open a socket for the local X server. */ | |
2442 | display = getenv("DISPLAY"); | |
2443 | if (!display) { | |
2444 | error("DISPLAY not set."); | |
2445 | return -1; | |
2446 | } | |
2447 | /* | |
2448 | * Now we decode the value of the DISPLAY variable and make a | |
2449 | * connection to the real X server. | |
2450 | */ | |
2451 | ||
2452 | /* | |
2453 | * Check if it is a unix domain socket. Unix domain displays are in | |
2454 | * one of the following formats: unix:d[.s], :d[.s], ::d[.s] | |
2455 | */ | |
2456 | if (strncmp(display, "unix:", 5) == 0 || | |
2457 | display[0] == ':') { | |
2458 | /* Connect to the unix domain socket. */ | |
2459 | if (sscanf(strrchr(display, ':') + 1, "%d", &display_number) != 1) { | |
2460 | error("Could not parse display number from DISPLAY: %.100s", | |
1e608e42 | 2461 | display); |
3c0ef626 | 2462 | return -1; |
2463 | } | |
2464 | /* Create a socket. */ | |
2465 | sock = connect_local_xsocket(display_number); | |
2466 | if (sock < 0) | |
2467 | return -1; | |
2468 | ||
2469 | /* OK, we now have a connection to the display. */ | |
2470 | return sock; | |
2471 | } | |
2472 | /* | |
2473 | * Connect to an inet socket. The DISPLAY value is supposedly | |
2474 | * hostname:d[.s], where hostname may also be numeric IP address. | |
2475 | */ | |
1e608e42 | 2476 | strlcpy(buf, display, sizeof(buf)); |
3c0ef626 | 2477 | cp = strchr(buf, ':'); |
2478 | if (!cp) { | |
2479 | error("Could not find ':' in DISPLAY: %.100s", display); | |
2480 | return -1; | |
2481 | } | |
2482 | *cp = 0; | |
2483 | /* buf now contains the host name. But first we parse the display number. */ | |
2484 | if (sscanf(cp + 1, "%d", &display_number) != 1) { | |
2485 | error("Could not parse display number from DISPLAY: %.100s", | |
1e608e42 | 2486 | display); |
3c0ef626 | 2487 | return -1; |
2488 | } | |
2489 | ||
2490 | /* Look up the host address */ | |
2491 | memset(&hints, 0, sizeof(hints)); | |
2492 | hints.ai_family = IPv4or6; | |
2493 | hints.ai_socktype = SOCK_STREAM; | |
2494 | snprintf(strport, sizeof strport, "%d", 6000 + display_number); | |
2495 | if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) { | |
2496 | error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr)); | |
2497 | return -1; | |
2498 | } | |
2499 | for (ai = aitop; ai; ai = ai->ai_next) { | |
2500 | /* Create a socket. */ | |
2501 | sock = socket(ai->ai_family, SOCK_STREAM, 0); | |
2502 | if (sock < 0) { | |
2503 | debug("socket: %.100s", strerror(errno)); | |
2504 | continue; | |
2505 | } | |
2506 | /* Connect it to the display. */ | |
2507 | if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) { | |
2508 | debug("connect %.100s port %d: %.100s", buf, | |
2509 | 6000 + display_number, strerror(errno)); | |
2510 | close(sock); | |
2511 | continue; | |
2512 | } | |
2513 | /* Success */ | |
2514 | break; | |
2515 | } | |
2516 | freeaddrinfo(aitop); | |
2517 | if (!ai) { | |
2518 | error("connect %.100s port %d: %.100s", buf, 6000 + display_number, | |
2519 | strerror(errno)); | |
2520 | return -1; | |
2521 | } | |
1e608e42 | 2522 | set_nodelay(sock); |
3c0ef626 | 2523 | return sock; |
2524 | } | |
2525 | ||
2526 | /* | |
2527 | * This is called when SSH_SMSG_X11_OPEN is received. The packet contains | |
2528 | * the remote channel number. We should do whatever we want, and respond | |
2529 | * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE. | |
2530 | */ | |
2531 | ||
2532 | void | |
1e608e42 | 2533 | x11_input_open(int type, u_int32_t seq, void *ctxt) |
3c0ef626 | 2534 | { |
2535 | Channel *c = NULL; | |
2536 | int remote_id, sock = 0; | |
2537 | char *remote_host; | |
2538 | ||
2539 | debug("Received X11 open request."); | |
2540 | ||
2541 | remote_id = packet_get_int(); | |
2542 | ||
2543 | if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) { | |
2544 | remote_host = packet_get_string(NULL); | |
2545 | } else { | |
2546 | remote_host = xstrdup("unknown (remote did not supply name)"); | |
2547 | } | |
1e608e42 | 2548 | packet_check_eom(); |
3c0ef626 | 2549 | |
2550 | /* Obtain a connection to the real X display. */ | |
2551 | sock = x11_connect_display(); | |
2552 | if (sock != -1) { | |
2553 | /* Allocate a channel for this connection. */ | |
2554 | c = channel_new("connected x11 socket", | |
2555 | SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0, | |
2556 | remote_host, 1); | |
1e608e42 | 2557 | c->remote_id = remote_id; |
2558 | c->force_drain = 1; | |
3c0ef626 | 2559 | } |
2560 | if (c == NULL) { | |
2561 | /* Send refusal to the remote host. */ | |
2562 | packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); | |
2563 | packet_put_int(remote_id); | |
2564 | } else { | |
2565 | /* Send a confirmation to the remote host. */ | |
2566 | packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION); | |
2567 | packet_put_int(remote_id); | |
2568 | packet_put_int(c->self); | |
2569 | } | |
2570 | packet_send(); | |
2571 | } | |
2572 | ||
2573 | /* dummy protocol handler that denies SSH-1 requests (agent/x11) */ | |
2574 | void | |
1e608e42 | 2575 | deny_input_open(int type, u_int32_t seq, void *ctxt) |
3c0ef626 | 2576 | { |
2577 | int rchan = packet_get_int(); | |
1e608e42 | 2578 | switch (type) { |
3c0ef626 | 2579 | case SSH_SMSG_AGENT_OPEN: |
2580 | error("Warning: ssh server tried agent forwarding."); | |
2581 | break; | |
2582 | case SSH_SMSG_X11_OPEN: | |
2583 | error("Warning: ssh server tried X11 forwarding."); | |
2584 | break; | |
2585 | default: | |
1e608e42 | 2586 | error("deny_input_open: type %d", type); |
3c0ef626 | 2587 | break; |
2588 | } | |
2589 | error("Warning: this is probably a break in attempt by a malicious server."); | |
2590 | packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); | |
2591 | packet_put_int(rchan); | |
2592 | packet_send(); | |
2593 | } | |
2594 | ||
2595 | /* | |
2596 | * Requests forwarding of X11 connections, generates fake authentication | |
2597 | * data, and enables authentication spoofing. | |
2598 | * This should be called in the client only. | |
2599 | */ | |
2600 | void | |
2601 | x11_request_forwarding_with_spoofing(int client_session_id, | |
2602 | const char *proto, const char *data) | |
2603 | { | |
2604 | u_int data_len = (u_int) strlen(data) / 2; | |
2605 | u_int i, value, len; | |
2606 | char *new_data; | |
2607 | int screen_number; | |
2608 | const char *cp; | |
2609 | u_int32_t rand = 0; | |
2610 | ||
2611 | cp = getenv("DISPLAY"); | |
2612 | if (cp) | |
2613 | cp = strchr(cp, ':'); | |
2614 | if (cp) | |
2615 | cp = strchr(cp, '.'); | |
2616 | if (cp) | |
2617 | screen_number = atoi(cp + 1); | |
2618 | else | |
2619 | screen_number = 0; | |
2620 | ||
2621 | /* Save protocol name. */ | |
2622 | x11_saved_proto = xstrdup(proto); | |
2623 | ||
2624 | /* | |
2625 | * Extract real authentication data and generate fake data of the | |
2626 | * same length. | |
2627 | */ | |
2628 | x11_saved_data = xmalloc(data_len); | |
2629 | x11_fake_data = xmalloc(data_len); | |
2630 | for (i = 0; i < data_len; i++) { | |
2631 | if (sscanf(data + 2 * i, "%2x", &value) != 1) | |
2632 | fatal("x11_request_forwarding: bad authentication data: %.100s", data); | |
2633 | if (i % 4 == 0) | |
2634 | rand = arc4random(); | |
2635 | x11_saved_data[i] = value; | |
2636 | x11_fake_data[i] = rand & 0xff; | |
2637 | rand >>= 8; | |
2638 | } | |
2639 | x11_saved_data_len = data_len; | |
2640 | x11_fake_data_len = data_len; | |
2641 | ||
2642 | /* Convert the fake data into hex. */ | |
2643 | len = 2 * data_len + 1; | |
2644 | new_data = xmalloc(len); | |
2645 | for (i = 0; i < data_len; i++) | |
2646 | snprintf(new_data + 2 * i, len - 2 * i, | |
2647 | "%02x", (u_char) x11_fake_data[i]); | |
2648 | ||
2649 | /* Send the request packet. */ | |
2650 | if (compat20) { | |
2651 | channel_request_start(client_session_id, "x11-req", 0); | |
2652 | packet_put_char(0); /* XXX bool single connection */ | |
2653 | } else { | |
2654 | packet_start(SSH_CMSG_X11_REQUEST_FORWARDING); | |
2655 | } | |
2656 | packet_put_cstring(proto); | |
2657 | packet_put_cstring(new_data); | |
2658 | packet_put_int(screen_number); | |
2659 | packet_send(); | |
2660 | packet_write_wait(); | |
2661 | xfree(new_data); | |
2662 | } | |
2663 | ||
2664 | ||
2665 | /* -- agent forwarding */ | |
2666 | ||
2667 | /* Sends a message to the server to request authentication fd forwarding. */ | |
2668 | ||
2669 | void | |
1e608e42 | 2670 | auth_request_forwarding(void) |
3c0ef626 | 2671 | { |
2672 | packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING); | |
2673 | packet_send(); | |
2674 | packet_write_wait(); | |
2675 | } | |
2676 | ||
2677 | /* | |
2678 | * Returns the name of the forwarded authentication socket. Returns NULL if | |
2679 | * there is no forwarded authentication socket. The returned value points to | |
2680 | * a static buffer. | |
2681 | */ | |
2682 | ||
2683 | char * | |
1e608e42 | 2684 | auth_get_socket_name(void) |
3c0ef626 | 2685 | { |
2686 | return auth_sock_name; | |
2687 | } | |
2688 | ||
2689 | /* removes the agent forwarding socket */ | |
2690 | ||
2691 | void | |
2692 | auth_sock_cleanup_proc(void *_pw) | |
2693 | { | |
2694 | struct passwd *pw = _pw; | |
2695 | ||
2696 | if (auth_sock_name) { | |
2697 | temporarily_use_uid(pw); | |
2698 | unlink(auth_sock_name); | |
2699 | rmdir(auth_sock_dir); | |
2700 | auth_sock_name = NULL; | |
2701 | restore_uid(); | |
2702 | } | |
2703 | } | |
2704 | ||
2705 | /* | |
2706 | * This is called to process SSH_CMSG_AGENT_REQUEST_FORWARDING on the server. | |
2707 | * This starts forwarding authentication requests. | |
2708 | */ | |
2709 | ||
2710 | int | |
2711 | auth_input_request_forwarding(struct passwd * pw) | |
2712 | { | |
2713 | Channel *nc; | |
2714 | int sock; | |
2715 | struct sockaddr_un sunaddr; | |
2716 | ||
2717 | if (auth_get_socket_name() != NULL) { | |
2718 | error("authentication forwarding requested twice."); | |
2719 | return 0; | |
2720 | } | |
2721 | ||
2722 | /* Temporarily drop privileged uid for mkdir/bind. */ | |
2723 | temporarily_use_uid(pw); | |
2724 | ||
2725 | /* Allocate a buffer for the socket name, and format the name. */ | |
2726 | auth_sock_name = xmalloc(MAXPATHLEN); | |
2727 | auth_sock_dir = xmalloc(MAXPATHLEN); | |
2728 | strlcpy(auth_sock_dir, "/tmp/ssh-XXXXXXXX", MAXPATHLEN); | |
2729 | ||
2730 | /* Create private directory for socket */ | |
2731 | if (mkdtemp(auth_sock_dir) == NULL) { | |
2732 | packet_send_debug("Agent forwarding disabled: " | |
2733 | "mkdtemp() failed: %.100s", strerror(errno)); | |
2734 | restore_uid(); | |
2735 | xfree(auth_sock_name); | |
2736 | xfree(auth_sock_dir); | |
2737 | auth_sock_name = NULL; | |
2738 | auth_sock_dir = NULL; | |
2739 | return 0; | |
2740 | } | |
2741 | snprintf(auth_sock_name, MAXPATHLEN, "%s/agent.%d", | |
2742 | auth_sock_dir, (int) getpid()); | |
2743 | ||
2744 | /* delete agent socket on fatal() */ | |
2745 | fatal_add_cleanup(auth_sock_cleanup_proc, pw); | |
2746 | ||
2747 | /* Create the socket. */ | |
2748 | sock = socket(AF_UNIX, SOCK_STREAM, 0); | |
2749 | if (sock < 0) | |
2750 | packet_disconnect("socket: %.100s", strerror(errno)); | |
2751 | ||
2752 | /* Bind it to the name. */ | |
2753 | memset(&sunaddr, 0, sizeof(sunaddr)); | |
2754 | sunaddr.sun_family = AF_UNIX; | |
1e608e42 | 2755 | strlcpy(sunaddr.sun_path, auth_sock_name, sizeof(sunaddr.sun_path)); |
3c0ef626 | 2756 | |
2757 | if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0) | |
2758 | packet_disconnect("bind: %.100s", strerror(errno)); | |
2759 | ||
2760 | /* Restore the privileged uid. */ | |
2761 | restore_uid(); | |
2762 | ||
2763 | /* Start listening on the socket. */ | |
2764 | if (listen(sock, 5) < 0) | |
2765 | packet_disconnect("listen: %.100s", strerror(errno)); | |
2766 | ||
2767 | /* Allocate a channel for the authentication agent socket. */ | |
2768 | nc = channel_new("auth socket", | |
2769 | SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1, | |
2770 | CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, | |
2771 | 0, xstrdup("auth socket"), 1); | |
3c0ef626 | 2772 | strlcpy(nc->path, auth_sock_name, sizeof(nc->path)); |
2773 | return 1; | |
2774 | } | |
2775 | ||
2776 | /* This is called to process an SSH_SMSG_AGENT_OPEN message. */ | |
2777 | ||
2778 | void | |
1e608e42 | 2779 | auth_input_open_request(int type, u_int32_t seq, void *ctxt) |
3c0ef626 | 2780 | { |
2781 | Channel *c = NULL; | |
2782 | int remote_id, sock; | |
2783 | char *name; | |
2784 | ||
3c0ef626 | 2785 | /* Read the remote channel number from the message. */ |
2786 | remote_id = packet_get_int(); | |
1e608e42 | 2787 | packet_check_eom(); |
3c0ef626 | 2788 | |
2789 | /* | |
2790 | * Get a connection to the local authentication agent (this may again | |
2791 | * get forwarded). | |
2792 | */ | |
2793 | sock = ssh_get_authentication_socket(); | |
2794 | ||
2795 | /* | |
2796 | * If we could not connect the agent, send an error message back to | |
2797 | * the server. This should never happen unless the agent dies, | |
2798 | * because authentication forwarding is only enabled if we have an | |
2799 | * agent. | |
2800 | */ | |
2801 | if (sock >= 0) { | |
2802 | name = xstrdup("authentication agent connection"); | |
2803 | c = channel_new("", SSH_CHANNEL_OPEN, sock, sock, | |
2804 | -1, 0, 0, 0, name, 1); | |
1e608e42 | 2805 | c->remote_id = remote_id; |
2806 | c->force_drain = 1; | |
3c0ef626 | 2807 | } |
2808 | if (c == NULL) { | |
2809 | packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); | |
2810 | packet_put_int(remote_id); | |
2811 | } else { | |
2812 | /* Send a confirmation to the remote host. */ | |
2813 | debug("Forwarding authentication connection."); | |
2814 | packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION); | |
2815 | packet_put_int(remote_id); | |
2816 | packet_put_int(c->self); | |
2817 | } | |
2818 | packet_send(); | |
2819 | } |