]>
Commit | Line | Data |
---|---|---|
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 1.41 2002/01/14 13:41:13 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 | static char *ostates[] = { "open", "drain", "wait_ieof", "closed" }; | |
87 | static char *istates[] = { "open", "drain", "wait_oclose", "closed" }; | |
88 | ||
89 | static void | |
90 | chan_set_istate(Channel *c, u_int next) | |
91 | { | |
92 | if (c->istate > CHAN_INPUT_CLOSED || next > CHAN_INPUT_CLOSED) | |
93 | fatal("chan_set_istate: bad state %d -> %d", c->istate, next); | |
94 | debug("channel %d: input %s -> %s", c->self, istates[c->istate], | |
95 | istates[next]); | |
96 | c->istate = next; | |
97 | } | |
98 | static void | |
99 | chan_set_ostate(Channel *c, u_int next) | |
100 | { | |
101 | if (c->ostate > CHAN_OUTPUT_CLOSED || next > CHAN_OUTPUT_CLOSED) | |
102 | fatal("chan_set_ostate: bad state %d -> %d", c->ostate, next); | |
103 | debug("channel %d: output %s -> %s", c->self, ostates[c->ostate], | |
104 | ostates[next]); | |
105 | c->ostate = next; | |
106 | } | |
107 | ||
108 | /* | |
109 | * SSH1 specific implementation of event functions | |
110 | */ | |
111 | ||
112 | static void | |
113 | chan_rcvd_oclose1(Channel *c) | |
114 | { | |
115 | debug("channel %d: rcvd oclose", c->self); | |
116 | switch (c->istate) { | |
117 | case CHAN_INPUT_WAIT_OCLOSE: | |
118 | chan_set_istate(c, CHAN_INPUT_CLOSED); | |
119 | break; | |
120 | case CHAN_INPUT_OPEN: | |
121 | chan_shutdown_read(c); | |
122 | chan_send_ieof1(c); | |
123 | chan_set_istate(c, CHAN_INPUT_CLOSED); | |
124 | break; | |
125 | case CHAN_INPUT_WAIT_DRAIN: | |
126 | /* both local read_failed and remote write_failed */ | |
127 | chan_send_ieof1(c); | |
128 | chan_set_istate(c, CHAN_INPUT_CLOSED); | |
129 | break; | |
130 | default: | |
131 | error("channel %d: protocol error: rcvd_oclose for istate %d", | |
132 | c->self, c->istate); | |
133 | return; | |
134 | } | |
135 | } | |
136 | static void | |
137 | chan_read_failed_12(Channel *c) | |
138 | { | |
139 | debug("channel %d: read failed", c->self); | |
140 | switch (c->istate) { | |
141 | case CHAN_INPUT_OPEN: | |
142 | chan_shutdown_read(c); | |
143 | chan_set_istate(c, CHAN_INPUT_WAIT_DRAIN); | |
144 | break; | |
145 | default: | |
146 | error("channel %d: chan_read_failed for istate %d", | |
147 | c->self, c->istate); | |
148 | break; | |
149 | } | |
150 | } | |
151 | static void | |
152 | chan_ibuf_empty1(Channel *c) | |
153 | { | |
154 | debug("channel %d: ibuf empty", c->self); | |
155 | if (buffer_len(&c->input)) { | |
156 | error("channel %d: chan_ibuf_empty for non empty buffer", | |
157 | c->self); | |
158 | return; | |
159 | } | |
160 | switch (c->istate) { | |
161 | case CHAN_INPUT_WAIT_DRAIN: | |
162 | if (compat20) { | |
163 | if (!(c->flags & CHAN_CLOSE_SENT)) | |
164 | chan_send_eof2(c); | |
165 | chan_set_istate(c, CHAN_INPUT_CLOSED); | |
166 | } else { | |
167 | chan_send_ieof1(c); | |
168 | chan_set_istate(c, CHAN_INPUT_WAIT_OCLOSE); | |
169 | } | |
170 | break; | |
171 | default: | |
172 | error("channel %d: chan_ibuf_empty for istate %d", | |
173 | c->self, c->istate); | |
174 | break; | |
175 | } | |
176 | } | |
177 | static void | |
178 | chan_rcvd_ieof1(Channel *c) | |
179 | { | |
180 | debug("channel %d: rcvd ieof", c->self); | |
181 | switch (c->ostate) { | |
182 | case CHAN_OUTPUT_OPEN: | |
183 | chan_set_ostate(c, CHAN_OUTPUT_WAIT_DRAIN); | |
184 | break; | |
185 | case CHAN_OUTPUT_WAIT_IEOF: | |
186 | chan_set_ostate(c, CHAN_OUTPUT_CLOSED); | |
187 | break; | |
188 | default: | |
189 | error("channel %d: protocol error: rcvd_ieof for ostate %d", | |
190 | c->self, c->ostate); | |
191 | break; | |
192 | } | |
193 | } | |
194 | static void | |
195 | chan_write_failed1(Channel *c) | |
196 | { | |
197 | debug("channel %d: write failed", c->self); | |
198 | switch (c->ostate) { | |
199 | case CHAN_OUTPUT_OPEN: | |
200 | chan_shutdown_write(c); | |
201 | chan_send_oclose1(c); | |
202 | chan_set_ostate(c, CHAN_OUTPUT_WAIT_IEOF); | |
203 | break; | |
204 | case CHAN_OUTPUT_WAIT_DRAIN: | |
205 | chan_shutdown_write(c); | |
206 | chan_send_oclose1(c); | |
207 | chan_set_ostate(c, CHAN_OUTPUT_CLOSED); | |
208 | break; | |
209 | default: | |
210 | error("channel %d: chan_write_failed for ostate %d", | |
211 | c->self, c->ostate); | |
212 | break; | |
213 | } | |
214 | } | |
215 | static void | |
216 | chan_obuf_empty1(Channel *c) | |
217 | { | |
218 | debug("channel %d: obuf empty", c->self); | |
219 | if (buffer_len(&c->output)) { | |
220 | error("channel %d: chan_obuf_empty for non empty buffer", | |
221 | c->self); | |
222 | return; | |
223 | } | |
224 | switch (c->ostate) { | |
225 | case CHAN_OUTPUT_WAIT_DRAIN: | |
226 | chan_shutdown_write(c); | |
227 | if (!compat20) | |
228 | chan_send_oclose1(c); | |
229 | chan_set_ostate(c, CHAN_OUTPUT_CLOSED); | |
230 | break; | |
231 | default: | |
232 | error("channel %d: internal error: obuf_empty for ostate %d", | |
233 | c->self, c->ostate); | |
234 | break; | |
235 | } | |
236 | } | |
237 | static void | |
238 | chan_send_ieof1(Channel *c) | |
239 | { | |
240 | debug("channel %d: send ieof", c->self); | |
241 | switch (c->istate) { | |
242 | case CHAN_INPUT_OPEN: | |
243 | case CHAN_INPUT_WAIT_DRAIN: | |
244 | packet_start(SSH_MSG_CHANNEL_INPUT_EOF); | |
245 | packet_put_int(c->remote_id); | |
246 | packet_send(); | |
247 | break; | |
248 | default: | |
249 | error("channel %d: cannot send ieof for istate %d", | |
250 | c->self, c->istate); | |
251 | break; | |
252 | } | |
253 | } | |
254 | static void | |
255 | chan_send_oclose1(Channel *c) | |
256 | { | |
257 | debug("channel %d: send oclose", c->self); | |
258 | switch (c->ostate) { | |
259 | case CHAN_OUTPUT_OPEN: | |
260 | case CHAN_OUTPUT_WAIT_DRAIN: | |
261 | buffer_clear(&c->output); | |
262 | packet_start(SSH_MSG_CHANNEL_OUTPUT_CLOSE); | |
263 | packet_put_int(c->remote_id); | |
264 | packet_send(); | |
265 | break; | |
266 | default: | |
267 | error("channel %d: cannot send oclose for ostate %d", | |
268 | c->self, c->ostate); | |
269 | break; | |
270 | } | |
271 | } | |
272 | ||
273 | /* | |
274 | * the same for SSH2 | |
275 | */ | |
276 | static void | |
277 | chan_rcvd_close2(Channel *c) | |
278 | { | |
279 | debug("channel %d: rcvd close", c->self); | |
280 | if (c->flags & CHAN_CLOSE_RCVD) | |
281 | error("channel %d: protocol error: close rcvd twice", c->self); | |
282 | c->flags |= CHAN_CLOSE_RCVD; | |
283 | if (c->type == SSH_CHANNEL_LARVAL) { | |
284 | /* tear down larval channels immediately */ | |
285 | chan_set_ostate(c, CHAN_OUTPUT_CLOSED); | |
286 | chan_set_istate(c, CHAN_INPUT_CLOSED); | |
287 | return; | |
288 | } | |
289 | switch (c->ostate) { | |
290 | case CHAN_OUTPUT_OPEN: | |
291 | /* | |
292 | * wait until a data from the channel is consumed if a CLOSE | |
293 | * is received | |
294 | */ | |
295 | chan_set_ostate(c, CHAN_OUTPUT_WAIT_DRAIN); | |
296 | break; | |
297 | } | |
298 | switch (c->istate) { | |
299 | case CHAN_INPUT_OPEN: | |
300 | chan_shutdown_read(c); | |
301 | chan_set_istate(c, CHAN_INPUT_CLOSED); | |
302 | break; | |
303 | case CHAN_INPUT_WAIT_DRAIN: | |
304 | chan_send_eof2(c); | |
305 | chan_set_istate(c, CHAN_INPUT_CLOSED); | |
306 | break; | |
307 | } | |
308 | } | |
309 | static void | |
310 | chan_ibuf_empty2(Channel *c) | |
311 | { | |
312 | chan_ibuf_empty1(c); | |
313 | } | |
314 | static void | |
315 | chan_rcvd_eof2(Channel *c) | |
316 | { | |
317 | debug("channel %d: rcvd eof", c->self); | |
318 | if (c->ostate == CHAN_OUTPUT_OPEN) | |
319 | chan_set_ostate(c, CHAN_OUTPUT_WAIT_DRAIN); | |
320 | } | |
321 | static void | |
322 | chan_write_failed2(Channel *c) | |
323 | { | |
324 | debug("channel %d: write failed", c->self); | |
325 | switch (c->ostate) { | |
326 | case CHAN_OUTPUT_OPEN: | |
327 | case CHAN_OUTPUT_WAIT_DRAIN: | |
328 | chan_shutdown_write(c); | |
329 | chan_set_ostate(c, CHAN_OUTPUT_CLOSED); | |
330 | break; | |
331 | default: | |
332 | error("channel %d: chan_write_failed for ostate %d", | |
333 | c->self, c->ostate); | |
334 | break; | |
335 | } | |
336 | } | |
337 | static void | |
338 | chan_obuf_empty2(Channel *c) | |
339 | { | |
340 | chan_obuf_empty1(c); | |
341 | } | |
342 | static void | |
343 | chan_send_eof2(Channel *c) | |
344 | { | |
345 | debug("channel %d: send eof", c->self); | |
346 | switch (c->istate) { | |
347 | case CHAN_INPUT_WAIT_DRAIN: | |
348 | packet_start(SSH2_MSG_CHANNEL_EOF); | |
349 | packet_put_int(c->remote_id); | |
350 | packet_send(); | |
351 | break; | |
352 | default: | |
353 | error("channel %d: cannot send eof for istate %d", | |
354 | c->self, c->istate); | |
355 | break; | |
356 | } | |
357 | } | |
358 | static void | |
359 | chan_send_close2(Channel *c) | |
360 | { | |
361 | debug("channel %d: send close", c->self); | |
362 | if (c->ostate != CHAN_OUTPUT_CLOSED || | |
363 | c->istate != CHAN_INPUT_CLOSED) { | |
364 | error("channel %d: cannot send close for istate/ostate %d/%d", | |
365 | c->self, c->istate, c->ostate); | |
366 | } else if (c->flags & CHAN_CLOSE_SENT) { | |
367 | error("channel %d: already sent close", c->self); | |
368 | } else { | |
369 | packet_start(SSH2_MSG_CHANNEL_CLOSE); | |
370 | packet_put_int(c->remote_id); | |
371 | packet_send(); | |
372 | c->flags |= CHAN_CLOSE_SENT; | |
373 | } | |
374 | } | |
375 | ||
376 | /* shared */ | |
377 | ||
378 | void | |
379 | chan_mark_dead(Channel *c) | |
380 | { | |
381 | c->type = SSH_CHANNEL_ZOMBIE; | |
382 | } | |
383 | ||
384 | int | |
385 | chan_is_dead(Channel *c, int send) | |
386 | { | |
387 | if (c->type == SSH_CHANNEL_ZOMBIE) { | |
388 | debug("channel %d: zombie", c->self); | |
389 | return 1; | |
390 | } | |
391 | if (c->istate != CHAN_INPUT_CLOSED || c->ostate != CHAN_OUTPUT_CLOSED) | |
392 | return 0; | |
393 | if (!compat20) { | |
394 | debug("channel %d: is dead", c->self); | |
395 | return 1; | |
396 | } | |
397 | /* | |
398 | * we have to delay the close message if the efd (for stderr) is | |
399 | * still active | |
400 | */ | |
401 | if (((c->extended_usage != CHAN_EXTENDED_IGNORE) && | |
402 | buffer_len(&c->extended) > 0) | |
403 | #if 0 | |
404 | || ((c->extended_usage == CHAN_EXTENDED_READ) && | |
405 | c->efd != -1) | |
406 | #endif | |
407 | ) { | |
408 | debug2("channel %d: active efd: %d len %d type %s", | |
409 | c->self, c->efd, buffer_len(&c->extended), | |
410 | c->extended_usage==CHAN_EXTENDED_READ ? | |
411 | "read": "write"); | |
412 | } else { | |
413 | if (!(c->flags & CHAN_CLOSE_SENT)) { | |
414 | if (send) { | |
415 | chan_send_close2(c); | |
416 | } else { | |
417 | /* channel would be dead if we sent a close */ | |
418 | if (c->flags & CHAN_CLOSE_RCVD) { | |
419 | debug("channel %d: almost dead", | |
420 | c->self); | |
421 | return 1; | |
422 | } | |
423 | } | |
424 | } | |
425 | if ((c->flags & CHAN_CLOSE_SENT) && | |
426 | (c->flags & CHAN_CLOSE_RCVD)) { | |
427 | debug("channel %d: is dead", c->self); | |
428 | return 1; | |
429 | } | |
430 | } | |
431 | return 0; | |
432 | } | |
433 | ||
434 | void | |
435 | chan_init_iostates(Channel *c) | |
436 | { | |
437 | c->ostate = CHAN_OUTPUT_OPEN; | |
438 | c->istate = CHAN_INPUT_OPEN; | |
439 | c->flags = 0; | |
440 | } | |
441 | ||
442 | /* init */ | |
443 | void | |
444 | chan_init(void) | |
445 | { | |
446 | if (compat20) { | |
447 | chan_rcvd_oclose = chan_rcvd_close2; | |
448 | chan_read_failed = chan_read_failed_12; | |
449 | chan_ibuf_empty = chan_ibuf_empty2; | |
450 | ||
451 | chan_rcvd_ieof = chan_rcvd_eof2; | |
452 | chan_write_failed = chan_write_failed2; | |
453 | chan_obuf_empty = chan_obuf_empty2; | |
454 | } else { | |
455 | chan_rcvd_oclose = chan_rcvd_oclose1; | |
456 | chan_read_failed = chan_read_failed_12; | |
457 | chan_ibuf_empty = chan_ibuf_empty1; | |
458 | ||
459 | chan_rcvd_ieof = chan_rcvd_ieof1; | |
460 | chan_write_failed = chan_write_failed1; | |
461 | chan_obuf_empty = chan_obuf_empty1; | |
462 | } | |
463 | } | |
464 | ||
465 | /* helper */ | |
466 | static void | |
467 | chan_shutdown_write(Channel *c) | |
468 | { | |
469 | buffer_clear(&c->output); | |
470 | if (compat20 && c->type == SSH_CHANNEL_LARVAL) | |
471 | return; | |
472 | /* shutdown failure is allowed if write failed already */ | |
473 | debug("channel %d: close_write", c->self); | |
474 | if (c->sock != -1) { | |
475 | if (shutdown(c->sock, SHUT_WR) < 0) | |
476 | debug("channel %d: chan_shutdown_write: " | |
477 | "shutdown() failed for fd%d: %.100s", | |
478 | c->self, c->sock, strerror(errno)); | |
479 | } else { | |
480 | if (channel_close_fd(&c->wfd) < 0) | |
481 | log("channel %d: chan_shutdown_write: " | |
482 | "close() failed for fd%d: %.100s", | |
483 | c->self, c->wfd, strerror(errno)); | |
484 | } | |
485 | } | |
486 | static void | |
487 | chan_shutdown_read(Channel *c) | |
488 | { | |
489 | if (compat20 && c->type == SSH_CHANNEL_LARVAL) | |
490 | return; | |
491 | debug("channel %d: close_read", c->self); | |
492 | if (c->sock != -1) { | |
493 | /* | |
494 | * shutdown(sock, SHUT_READ) may return ENOTCONN if the | |
495 | * write side has been closed already. (bug on Linux) | |
496 | * HP-UX may return ENOTCONN also. | |
497 | */ | |
498 | if (shutdown(c->sock, SHUT_RD) < 0 | |
499 | && errno != ENOTCONN) | |
500 | error("channel %d: chan_shutdown_read: " | |
501 | "shutdown() failed for fd%d [i%d o%d]: %.100s", | |
502 | c->self, c->sock, c->istate, c->ostate, | |
503 | strerror(errno)); | |
504 | } else { | |
505 | if (channel_close_fd(&c->rfd) < 0) | |
506 | log("channel %d: chan_shutdown_read: " | |
507 | "close() failed for fd%d: %.100s", | |
508 | c->self, c->rfd, strerror(errno)); | |
509 | } | |
510 | } |