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3c0ef626 | 1 | /* |
2 | * Copyright (c) 1999, 2000, 2001 Markus Friedl. All rights reserved. | |
3 | * | |
4 | * Redistribution and use in source and binary forms, with or without | |
5 | * modification, are permitted provided that the following conditions | |
6 | * are met: | |
7 | * 1. Redistributions of source code must retain the above copyright | |
8 | * notice, this list of conditions and the following disclaimer. | |
9 | * 2. Redistributions in binary form must reproduce the above copyright | |
10 | * notice, this list of conditions and the following disclaimer in the | |
11 | * documentation and/or other materials provided with the distribution. | |
12 | * | |
13 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR | |
14 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES | |
15 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. | |
16 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, | |
17 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | |
18 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
19 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
20 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
21 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF | |
22 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
23 | */ | |
24 | ||
25 | #include "includes.h" | |
26 | RCSID("$OpenBSD: nchan.c,v 1.32 2001/10/10 22:18:47 markus Exp $"); | |
27 | ||
28 | #include "ssh1.h" | |
29 | #include "ssh2.h" | |
30 | #include "buffer.h" | |
31 | #include "packet.h" | |
32 | #include "channels.h" | |
33 | #include "compat.h" | |
34 | #include "log.h" | |
35 | ||
36 | /* | |
37 | * SSH Protocol 1.5 aka New Channel Protocol | |
38 | * Thanks to Martina, Axel and everyone who left Erlangen, leaving me bored. | |
39 | * Written by Markus Friedl in October 1999 | |
40 | * | |
41 | * Protocol versions 1.3 and 1.5 differ in the handshake protocol used for the | |
42 | * tear down of channels: | |
43 | * | |
44 | * 1.3: strict request-ack-protocol: | |
45 | * CLOSE -> | |
46 | * <- CLOSE_CONFIRM | |
47 | * | |
48 | * 1.5: uses variations of: | |
49 | * IEOF -> | |
50 | * <- OCLOSE | |
51 | * <- IEOF | |
52 | * OCLOSE -> | |
53 | * i.e. both sides have to close the channel | |
54 | * | |
55 | * 2.0: the EOF messages are optional | |
56 | * | |
57 | * See the debugging output from 'ssh -v' and 'sshd -d' of | |
58 | * ssh-1.2.27 as an example. | |
59 | * | |
60 | */ | |
61 | ||
62 | /* functions manipulating channel states */ | |
63 | /* | |
64 | * EVENTS update channel input/output states execute ACTIONS | |
65 | */ | |
66 | /* events concerning the INPUT from socket for channel (istate) */ | |
67 | chan_event_fn *chan_rcvd_oclose = NULL; | |
68 | chan_event_fn *chan_read_failed = NULL; | |
69 | chan_event_fn *chan_ibuf_empty = NULL; | |
70 | /* events concerning the OUTPUT from channel for socket (ostate) */ | |
71 | chan_event_fn *chan_rcvd_ieof = NULL; | |
72 | chan_event_fn *chan_write_failed = NULL; | |
73 | chan_event_fn *chan_obuf_empty = NULL; | |
74 | /* | |
75 | * ACTIONS: should never update the channel states | |
76 | */ | |
77 | static void chan_send_ieof1(Channel *); | |
78 | static void chan_send_oclose1(Channel *); | |
79 | static void chan_send_close2(Channel *); | |
80 | static void chan_send_eof2(Channel *); | |
81 | ||
82 | /* helper */ | |
83 | static void chan_shutdown_write(Channel *); | |
84 | static void chan_shutdown_read(Channel *); | |
85 | ||
86 | /* | |
87 | * SSH1 specific implementation of event functions | |
88 | */ | |
89 | ||
90 | static void | |
91 | chan_rcvd_oclose1(Channel *c) | |
92 | { | |
93 | debug("channel %d: rcvd oclose", c->self); | |
94 | switch (c->istate) { | |
95 | case CHAN_INPUT_WAIT_OCLOSE: | |
96 | debug("channel %d: input wait_oclose -> closed", c->self); | |
97 | c->istate = CHAN_INPUT_CLOSED; | |
98 | break; | |
99 | case CHAN_INPUT_OPEN: | |
100 | debug("channel %d: input open -> closed", c->self); | |
101 | chan_shutdown_read(c); | |
102 | chan_send_ieof1(c); | |
103 | c->istate = CHAN_INPUT_CLOSED; | |
104 | break; | |
105 | case CHAN_INPUT_WAIT_DRAIN: | |
106 | /* both local read_failed and remote write_failed */ | |
107 | log("channel %d: input drain -> closed", c->self); | |
108 | chan_send_ieof1(c); | |
109 | c->istate = CHAN_INPUT_CLOSED; | |
110 | break; | |
111 | default: | |
112 | error("channel %d: protocol error: rcvd_oclose for istate %d", | |
113 | c->self, c->istate); | |
114 | return; | |
115 | } | |
116 | } | |
117 | static void | |
118 | chan_read_failed_12(Channel *c) | |
119 | { | |
120 | debug("channel %d: read failed", c->self); | |
121 | switch (c->istate) { | |
122 | case CHAN_INPUT_OPEN: | |
123 | debug("channel %d: input open -> drain", c->self); | |
124 | chan_shutdown_read(c); | |
125 | c->istate = CHAN_INPUT_WAIT_DRAIN; | |
126 | #if 0 | |
127 | if (buffer_len(&c->input) == 0) { | |
128 | debug("channel %d: input: no drain shortcut", c->self); | |
129 | chan_ibuf_empty(c); | |
130 | } | |
131 | #endif | |
132 | break; | |
133 | default: | |
134 | error("channel %d: chan_read_failed for istate %d", | |
135 | c->self, c->istate); | |
136 | break; | |
137 | } | |
138 | } | |
139 | static void | |
140 | chan_ibuf_empty1(Channel *c) | |
141 | { | |
142 | debug("channel %d: ibuf empty", c->self); | |
143 | if (buffer_len(&c->input)) { | |
144 | error("channel %d: chan_ibuf_empty for non empty buffer", | |
145 | c->self); | |
146 | return; | |
147 | } | |
148 | switch (c->istate) { | |
149 | case CHAN_INPUT_WAIT_DRAIN: | |
150 | debug("channel %d: input drain -> wait_oclose", c->self); | |
151 | chan_send_ieof1(c); | |
152 | c->istate = CHAN_INPUT_WAIT_OCLOSE; | |
153 | break; | |
154 | default: | |
155 | error("channel %d: chan_ibuf_empty for istate %d", | |
156 | c->self, c->istate); | |
157 | break; | |
158 | } | |
159 | } | |
160 | static void | |
161 | chan_rcvd_ieof1(Channel *c) | |
162 | { | |
163 | debug("channel %d: rcvd ieof", c->self); | |
164 | if (c->type != SSH_CHANNEL_OPEN) { | |
165 | debug("channel %d: non-open", c->self); | |
166 | if (c->istate == CHAN_INPUT_OPEN) { | |
167 | debug("channel %d: non-open: input open -> wait_oclose", | |
168 | c->self); | |
169 | chan_shutdown_read(c); | |
170 | chan_send_ieof1(c); | |
171 | c->istate = CHAN_INPUT_WAIT_OCLOSE; | |
172 | } else { | |
173 | error("channel %d: non-open: istate %d != open", | |
174 | c->self, c->istate); | |
175 | } | |
176 | if (c->ostate == CHAN_OUTPUT_OPEN) { | |
177 | debug("channel %d: non-open: output open -> closed", | |
178 | c->self); | |
179 | chan_send_oclose1(c); | |
180 | c->ostate = CHAN_OUTPUT_CLOSED; | |
181 | } else { | |
182 | error("channel %d: non-open: ostate %d != open", | |
183 | c->self, c->ostate); | |
184 | } | |
185 | return; | |
186 | } | |
187 | switch (c->ostate) { | |
188 | case CHAN_OUTPUT_OPEN: | |
189 | debug("channel %d: output open -> drain", c->self); | |
190 | c->ostate = CHAN_OUTPUT_WAIT_DRAIN; | |
191 | break; | |
192 | case CHAN_OUTPUT_WAIT_IEOF: | |
193 | debug("channel %d: output wait_ieof -> closed", c->self); | |
194 | c->ostate = CHAN_OUTPUT_CLOSED; | |
195 | break; | |
196 | default: | |
197 | error("channel %d: protocol error: rcvd_ieof for ostate %d", | |
198 | c->self, c->ostate); | |
199 | break; | |
200 | } | |
201 | } | |
202 | static void | |
203 | chan_write_failed1(Channel *c) | |
204 | { | |
205 | debug("channel %d: write failed", c->self); | |
206 | switch (c->ostate) { | |
207 | case CHAN_OUTPUT_OPEN: | |
208 | debug("channel %d: output open -> wait_ieof", c->self); | |
209 | chan_send_oclose1(c); | |
210 | c->ostate = CHAN_OUTPUT_WAIT_IEOF; | |
211 | break; | |
212 | case CHAN_OUTPUT_WAIT_DRAIN: | |
213 | debug("channel %d: output wait_drain -> closed", c->self); | |
214 | chan_send_oclose1(c); | |
215 | c->ostate = CHAN_OUTPUT_CLOSED; | |
216 | break; | |
217 | default: | |
218 | error("channel %d: chan_write_failed for ostate %d", | |
219 | c->self, c->ostate); | |
220 | break; | |
221 | } | |
222 | } | |
223 | static void | |
224 | chan_obuf_empty1(Channel *c) | |
225 | { | |
226 | debug("channel %d: obuf empty", c->self); | |
227 | if (buffer_len(&c->output)) { | |
228 | error("channel %d: chan_obuf_empty for non empty buffer", | |
229 | c->self); | |
230 | return; | |
231 | } | |
232 | switch (c->ostate) { | |
233 | case CHAN_OUTPUT_WAIT_DRAIN: | |
234 | debug("channel %d: output drain -> closed", c->self); | |
235 | chan_send_oclose1(c); | |
236 | c->ostate = CHAN_OUTPUT_CLOSED; | |
237 | break; | |
238 | default: | |
239 | error("channel %d: internal error: obuf_empty for ostate %d", | |
240 | c->self, c->ostate); | |
241 | break; | |
242 | } | |
243 | } | |
244 | static void | |
245 | chan_send_ieof1(Channel *c) | |
246 | { | |
247 | debug("channel %d: send ieof", c->self); | |
248 | switch (c->istate) { | |
249 | case CHAN_INPUT_OPEN: | |
250 | case CHAN_INPUT_WAIT_DRAIN: | |
251 | packet_start(SSH_MSG_CHANNEL_INPUT_EOF); | |
252 | packet_put_int(c->remote_id); | |
253 | packet_send(); | |
254 | break; | |
255 | default: | |
256 | error("channel %d: cannot send ieof for istate %d", | |
257 | c->self, c->istate); | |
258 | break; | |
259 | } | |
260 | } | |
261 | static void | |
262 | chan_send_oclose1(Channel *c) | |
263 | { | |
264 | debug("channel %d: send oclose", c->self); | |
265 | switch (c->ostate) { | |
266 | case CHAN_OUTPUT_OPEN: | |
267 | case CHAN_OUTPUT_WAIT_DRAIN: | |
268 | chan_shutdown_write(c); | |
269 | buffer_consume(&c->output, buffer_len(&c->output)); | |
270 | packet_start(SSH_MSG_CHANNEL_OUTPUT_CLOSE); | |
271 | packet_put_int(c->remote_id); | |
272 | packet_send(); | |
273 | break; | |
274 | default: | |
275 | error("channel %d: cannot send oclose for ostate %d", | |
276 | c->self, c->ostate); | |
277 | break; | |
278 | } | |
279 | } | |
280 | ||
281 | /* | |
282 | * the same for SSH2 | |
283 | */ | |
284 | static void | |
285 | chan_rcvd_oclose2(Channel *c) | |
286 | { | |
287 | debug("channel %d: rcvd close", c->self); | |
288 | if (c->flags & CHAN_CLOSE_RCVD) | |
289 | error("channel %d: protocol error: close rcvd twice", c->self); | |
290 | c->flags |= CHAN_CLOSE_RCVD; | |
291 | if (c->type == SSH_CHANNEL_LARVAL) { | |
292 | /* tear down larval channels immediately */ | |
293 | c->ostate = CHAN_OUTPUT_CLOSED; | |
294 | c->istate = CHAN_INPUT_CLOSED; | |
295 | return; | |
296 | } | |
297 | switch (c->ostate) { | |
298 | case CHAN_OUTPUT_OPEN: | |
299 | /* | |
300 | * wait until a data from the channel is consumed if a CLOSE | |
301 | * is received | |
302 | */ | |
303 | debug("channel %d: output open -> drain", c->self); | |
304 | c->ostate = CHAN_OUTPUT_WAIT_DRAIN; | |
305 | break; | |
306 | } | |
307 | switch (c->istate) { | |
308 | case CHAN_INPUT_OPEN: | |
309 | debug("channel %d: input open -> closed", c->self); | |
310 | chan_shutdown_read(c); | |
311 | break; | |
312 | case CHAN_INPUT_WAIT_DRAIN: | |
313 | debug("channel %d: input drain -> closed", c->self); | |
314 | chan_send_eof2(c); | |
315 | break; | |
316 | } | |
317 | c->istate = CHAN_INPUT_CLOSED; | |
318 | } | |
319 | static void | |
320 | chan_ibuf_empty2(Channel *c) | |
321 | { | |
322 | debug("channel %d: ibuf empty", c->self); | |
323 | if (buffer_len(&c->input)) { | |
324 | error("channel %d: chan_ibuf_empty for non empty buffer", | |
325 | c->self); | |
326 | return; | |
327 | } | |
328 | switch (c->istate) { | |
329 | case CHAN_INPUT_WAIT_DRAIN: | |
330 | debug("channel %d: input drain -> closed", c->self); | |
331 | if (!(c->flags & CHAN_CLOSE_SENT)) | |
332 | chan_send_eof2(c); | |
333 | c->istate = CHAN_INPUT_CLOSED; | |
334 | break; | |
335 | default: | |
336 | error("channel %d: chan_ibuf_empty for istate %d", | |
337 | c->self, c->istate); | |
338 | break; | |
339 | } | |
340 | } | |
341 | static void | |
342 | chan_rcvd_ieof2(Channel *c) | |
343 | { | |
344 | debug("channel %d: rcvd eof", c->self); | |
345 | if (c->ostate == CHAN_OUTPUT_OPEN) { | |
346 | debug("channel %d: output open -> drain", c->self); | |
347 | c->ostate = CHAN_OUTPUT_WAIT_DRAIN; | |
348 | } | |
349 | } | |
350 | static void | |
351 | chan_write_failed2(Channel *c) | |
352 | { | |
353 | debug("channel %d: write failed", c->self); | |
354 | switch (c->ostate) { | |
355 | case CHAN_OUTPUT_OPEN: | |
356 | debug("channel %d: output open -> closed", c->self); | |
357 | chan_shutdown_write(c); /* ?? */ | |
358 | c->ostate = CHAN_OUTPUT_CLOSED; | |
359 | break; | |
360 | case CHAN_OUTPUT_WAIT_DRAIN: | |
361 | debug("channel %d: output drain -> closed", c->self); | |
362 | chan_shutdown_write(c); | |
363 | c->ostate = CHAN_OUTPUT_CLOSED; | |
364 | break; | |
365 | default: | |
366 | error("channel %d: chan_write_failed for ostate %d", | |
367 | c->self, c->ostate); | |
368 | break; | |
369 | } | |
370 | } | |
371 | static void | |
372 | chan_obuf_empty2(Channel *c) | |
373 | { | |
374 | debug("channel %d: obuf empty", c->self); | |
375 | if (buffer_len(&c->output)) { | |
376 | error("channel %d: chan_obuf_empty for non empty buffer", | |
377 | c->self); | |
378 | return; | |
379 | } | |
380 | switch (c->ostate) { | |
381 | case CHAN_OUTPUT_WAIT_DRAIN: | |
382 | debug("channel %d: output drain -> closed", c->self); | |
383 | chan_shutdown_write(c); | |
384 | c->ostate = CHAN_OUTPUT_CLOSED; | |
385 | break; | |
386 | default: | |
387 | error("channel %d: chan_obuf_empty for ostate %d", | |
388 | c->self, c->ostate); | |
389 | break; | |
390 | } | |
391 | } | |
392 | static void | |
393 | chan_send_eof2(Channel *c) | |
394 | { | |
395 | debug("channel %d: send eof", c->self); | |
396 | switch (c->istate) { | |
397 | case CHAN_INPUT_WAIT_DRAIN: | |
398 | packet_start(SSH2_MSG_CHANNEL_EOF); | |
399 | packet_put_int(c->remote_id); | |
400 | packet_send(); | |
401 | break; | |
402 | default: | |
403 | error("channel %d: cannot send eof for istate %d", | |
404 | c->self, c->istate); | |
405 | break; | |
406 | } | |
407 | } | |
408 | static void | |
409 | chan_send_close2(Channel *c) | |
410 | { | |
411 | debug("channel %d: send close", c->self); | |
412 | if (c->ostate != CHAN_OUTPUT_CLOSED || | |
413 | c->istate != CHAN_INPUT_CLOSED) { | |
414 | error("channel %d: cannot send close for istate/ostate %d/%d", | |
415 | c->self, c->istate, c->ostate); | |
416 | } else if (c->flags & CHAN_CLOSE_SENT) { | |
417 | error("channel %d: already sent close", c->self); | |
418 | } else { | |
419 | packet_start(SSH2_MSG_CHANNEL_CLOSE); | |
420 | packet_put_int(c->remote_id); | |
421 | packet_send(); | |
422 | c->flags |= CHAN_CLOSE_SENT; | |
423 | } | |
424 | } | |
425 | ||
426 | /* shared */ | |
427 | ||
428 | void | |
429 | chan_mark_dead(Channel *c) | |
430 | { | |
431 | c->type = SSH_CHANNEL_ZOMBIE; | |
432 | } | |
433 | ||
434 | int | |
435 | chan_is_dead(Channel *c, int send) | |
436 | { | |
437 | if (c->type == SSH_CHANNEL_ZOMBIE) { | |
438 | debug("channel %d: zombie", c->self); | |
439 | return 1; | |
440 | } | |
441 | if (c->istate != CHAN_INPUT_CLOSED || c->ostate != CHAN_OUTPUT_CLOSED) | |
442 | return 0; | |
443 | if (!compat20) { | |
444 | debug("channel %d: is dead", c->self); | |
445 | return 1; | |
446 | } | |
447 | /* | |
448 | * we have to delay the close message if the efd (for stderr) is | |
449 | * still active | |
450 | */ | |
451 | if (((c->extended_usage != CHAN_EXTENDED_IGNORE) && | |
452 | buffer_len(&c->extended) > 0) | |
453 | #if 0 | |
454 | || ((c->extended_usage == CHAN_EXTENDED_READ) && | |
455 | c->efd != -1) | |
456 | #endif | |
457 | ) { | |
458 | debug2("channel %d: active efd: %d len %d type %s", | |
459 | c->self, c->efd, buffer_len(&c->extended), | |
460 | c->extended_usage==CHAN_EXTENDED_READ ? | |
461 | "read": "write"); | |
462 | } else { | |
463 | if (!(c->flags & CHAN_CLOSE_SENT)) { | |
464 | if (send) { | |
465 | chan_send_close2(c); | |
466 | } else { | |
467 | /* channel would be dead if we sent a close */ | |
468 | if (c->flags & CHAN_CLOSE_RCVD) { | |
469 | debug("channel %d: almost dead", | |
470 | c->self); | |
471 | return 1; | |
472 | } | |
473 | } | |
474 | } | |
475 | if ((c->flags & CHAN_CLOSE_SENT) && | |
476 | (c->flags & CHAN_CLOSE_RCVD)) { | |
477 | debug("channel %d: is dead", c->self); | |
478 | return 1; | |
479 | } | |
480 | } | |
481 | return 0; | |
482 | } | |
483 | ||
484 | void | |
485 | chan_init_iostates(Channel *c) | |
486 | { | |
487 | c->ostate = CHAN_OUTPUT_OPEN; | |
488 | c->istate = CHAN_INPUT_OPEN; | |
489 | c->flags = 0; | |
490 | } | |
491 | ||
492 | /* init */ | |
493 | void | |
494 | chan_init(void) | |
495 | { | |
496 | if (compat20) { | |
497 | chan_rcvd_oclose = chan_rcvd_oclose2; | |
498 | chan_read_failed = chan_read_failed_12; | |
499 | chan_ibuf_empty = chan_ibuf_empty2; | |
500 | ||
501 | chan_rcvd_ieof = chan_rcvd_ieof2; | |
502 | chan_write_failed = chan_write_failed2; | |
503 | chan_obuf_empty = chan_obuf_empty2; | |
504 | } else { | |
505 | chan_rcvd_oclose = chan_rcvd_oclose1; | |
506 | chan_read_failed = chan_read_failed_12; | |
507 | chan_ibuf_empty = chan_ibuf_empty1; | |
508 | ||
509 | chan_rcvd_ieof = chan_rcvd_ieof1; | |
510 | chan_write_failed = chan_write_failed1; | |
511 | chan_obuf_empty = chan_obuf_empty1; | |
512 | } | |
513 | } | |
514 | ||
515 | /* helper */ | |
516 | static void | |
517 | chan_shutdown_write(Channel *c) | |
518 | { | |
519 | buffer_consume(&c->output, buffer_len(&c->output)); | |
520 | if (compat20 && c->type == SSH_CHANNEL_LARVAL) | |
521 | return; | |
522 | /* shutdown failure is allowed if write failed already */ | |
523 | debug("channel %d: close_write", c->self); | |
524 | if (c->sock != -1) { | |
525 | if (shutdown(c->sock, SHUT_WR) < 0) | |
526 | debug("channel %d: chan_shutdown_write: " | |
527 | "shutdown() failed for fd%d: %.100s", | |
528 | c->self, c->sock, strerror(errno)); | |
529 | } else { | |
530 | if (channel_close_fd(&c->wfd) < 0) | |
531 | log("channel %d: chan_shutdown_write: " | |
532 | "close() failed for fd%d: %.100s", | |
533 | c->self, c->wfd, strerror(errno)); | |
534 | } | |
535 | } | |
536 | static void | |
537 | chan_shutdown_read(Channel *c) | |
538 | { | |
539 | if (compat20 && c->type == SSH_CHANNEL_LARVAL) | |
540 | return; | |
541 | debug("channel %d: close_read", c->self); | |
542 | if (c->sock != -1) { | |
543 | /* | |
544 | * shutdown(sock, SHUT_READ) may return ENOTCONN if the | |
545 | * write side has been closed already. (bug on Linux) | |
546 | * HP-UX may return ENOTCONN also. | |
547 | */ | |
548 | if (shutdown(c->sock, SHUT_RD) < 0 | |
549 | && errno != ENOTCONN) | |
550 | error("channel %d: chan_shutdown_read: " | |
551 | "shutdown() failed for fd%d [i%d o%d]: %.100s", | |
552 | c->self, c->sock, c->istate, c->ostate, | |
553 | strerror(errno)); | |
554 | } else { | |
555 | if (channel_close_fd(&c->rfd) < 0) | |
556 | log("channel %d: chan_shutdown_read: " | |
557 | "close() failed for fd%d: %.100s", | |
558 | c->self, c->rfd, strerror(errno)); | |
559 | } | |
560 | } |