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1 | /* $OpenBSD: nchan.c,v 1.62 2008/11/07 18:50:18 stevesk Exp $ */ | |
2 | /* | |
3 | * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved. | |
4 | * | |
5 | * Redistribution and use in source and binary forms, with or without | |
6 | * modification, are permitted provided that the following conditions | |
7 | * are met: | |
8 | * 1. Redistributions of source code must retain the above copyright | |
9 | * notice, this list of conditions and the following disclaimer. | |
10 | * 2. Redistributions in binary form must reproduce the above copyright | |
11 | * notice, this list of conditions and the following disclaimer in the | |
12 | * documentation and/or other materials provided with the distribution. | |
13 | * | |
14 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR | |
15 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES | |
16 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. | |
17 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, | |
18 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | |
19 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
20 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
21 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
22 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF | |
23 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
24 | */ | |
25 | ||
26 | #include "includes.h" | |
27 | ||
28 | #include <sys/types.h> | |
29 | #include <sys/socket.h> | |
30 | ||
31 | #include <errno.h> | |
32 | #include <string.h> | |
33 | #include <stdarg.h> | |
34 | ||
35 | #include "openbsd-compat/sys-queue.h" | |
36 | #include "ssh1.h" | |
37 | #include "ssh2.h" | |
38 | #include "buffer.h" | |
39 | #include "packet.h" | |
40 | #include "channels.h" | |
41 | #include "compat.h" | |
42 | #include "log.h" | |
43 | ||
44 | /* | |
45 | * SSH Protocol 1.5 aka New Channel Protocol | |
46 | * Thanks to Martina, Axel and everyone who left Erlangen, leaving me bored. | |
47 | * Written by Markus Friedl in October 1999 | |
48 | * | |
49 | * Protocol versions 1.3 and 1.5 differ in the handshake protocol used for the | |
50 | * tear down of channels: | |
51 | * | |
52 | * 1.3: strict request-ack-protocol: | |
53 | * CLOSE -> | |
54 | * <- CLOSE_CONFIRM | |
55 | * | |
56 | * 1.5: uses variations of: | |
57 | * IEOF -> | |
58 | * <- OCLOSE | |
59 | * <- IEOF | |
60 | * OCLOSE -> | |
61 | * i.e. both sides have to close the channel | |
62 | * | |
63 | * 2.0: the EOF messages are optional | |
64 | * | |
65 | * See the debugging output from 'ssh -v' and 'sshd -d' of | |
66 | * ssh-1.2.27 as an example. | |
67 | * | |
68 | */ | |
69 | ||
70 | /* functions manipulating channel states */ | |
71 | /* | |
72 | * EVENTS update channel input/output states execute ACTIONS | |
73 | */ | |
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 | static void chan_send_eow2(Channel *); | |
82 | ||
83 | /* helper */ | |
84 | static void chan_shutdown_write(Channel *); | |
85 | static void chan_shutdown_read(Channel *); | |
86 | ||
87 | static char *ostates[] = { "open", "drain", "wait_ieof", "closed" }; | |
88 | static char *istates[] = { "open", "drain", "wait_oclose", "closed" }; | |
89 | ||
90 | static void | |
91 | chan_set_istate(Channel *c, u_int next) | |
92 | { | |
93 | if (c->istate > CHAN_INPUT_CLOSED || next > CHAN_INPUT_CLOSED) | |
94 | fatal("chan_set_istate: bad state %d -> %d", c->istate, next); | |
95 | debug2("channel %d: input %s -> %s", c->self, istates[c->istate], | |
96 | istates[next]); | |
97 | c->istate = next; | |
98 | } | |
99 | static void | |
100 | chan_set_ostate(Channel *c, u_int next) | |
101 | { | |
102 | if (c->ostate > CHAN_OUTPUT_CLOSED || next > CHAN_OUTPUT_CLOSED) | |
103 | fatal("chan_set_ostate: bad state %d -> %d", c->ostate, next); | |
104 | debug2("channel %d: output %s -> %s", c->self, ostates[c->ostate], | |
105 | ostates[next]); | |
106 | c->ostate = next; | |
107 | } | |
108 | ||
109 | /* | |
110 | * SSH1 specific implementation of event functions | |
111 | */ | |
112 | ||
113 | static void | |
114 | chan_rcvd_oclose1(Channel *c) | |
115 | { | |
116 | debug2("channel %d: rcvd oclose", c->self); | |
117 | switch (c->istate) { | |
118 | case CHAN_INPUT_WAIT_OCLOSE: | |
119 | chan_set_istate(c, CHAN_INPUT_CLOSED); | |
120 | break; | |
121 | case CHAN_INPUT_OPEN: | |
122 | chan_shutdown_read(c); | |
123 | chan_send_ieof1(c); | |
124 | chan_set_istate(c, CHAN_INPUT_CLOSED); | |
125 | break; | |
126 | case CHAN_INPUT_WAIT_DRAIN: | |
127 | /* both local read_failed and remote write_failed */ | |
128 | chan_send_ieof1(c); | |
129 | chan_set_istate(c, CHAN_INPUT_CLOSED); | |
130 | break; | |
131 | default: | |
132 | error("channel %d: protocol error: rcvd_oclose for istate %d", | |
133 | c->self, c->istate); | |
134 | return; | |
135 | } | |
136 | } | |
137 | void | |
138 | chan_read_failed(Channel *c) | |
139 | { | |
140 | debug2("channel %d: read failed", c->self); | |
141 | switch (c->istate) { | |
142 | case CHAN_INPUT_OPEN: | |
143 | chan_shutdown_read(c); | |
144 | chan_set_istate(c, CHAN_INPUT_WAIT_DRAIN); | |
145 | break; | |
146 | default: | |
147 | error("channel %d: chan_read_failed for istate %d", | |
148 | c->self, c->istate); | |
149 | break; | |
150 | } | |
151 | } | |
152 | void | |
153 | chan_ibuf_empty(Channel *c) | |
154 | { | |
155 | debug2("channel %d: ibuf empty", c->self); | |
156 | if (buffer_len(&c->input)) { | |
157 | error("channel %d: chan_ibuf_empty for non empty buffer", | |
158 | c->self); | |
159 | return; | |
160 | } | |
161 | switch (c->istate) { | |
162 | case CHAN_INPUT_WAIT_DRAIN: | |
163 | if (compat20) { | |
164 | if (!(c->flags & CHAN_CLOSE_SENT)) | |
165 | chan_send_eof2(c); | |
166 | chan_set_istate(c, CHAN_INPUT_CLOSED); | |
167 | } else { | |
168 | chan_send_ieof1(c); | |
169 | chan_set_istate(c, CHAN_INPUT_WAIT_OCLOSE); | |
170 | } | |
171 | break; | |
172 | default: | |
173 | error("channel %d: chan_ibuf_empty for istate %d", | |
174 | c->self, c->istate); | |
175 | break; | |
176 | } | |
177 | } | |
178 | static void | |
179 | chan_rcvd_ieof1(Channel *c) | |
180 | { | |
181 | debug2("channel %d: rcvd ieof", c->self); | |
182 | switch (c->ostate) { | |
183 | case CHAN_OUTPUT_OPEN: | |
184 | chan_set_ostate(c, CHAN_OUTPUT_WAIT_DRAIN); | |
185 | break; | |
186 | case CHAN_OUTPUT_WAIT_IEOF: | |
187 | chan_set_ostate(c, CHAN_OUTPUT_CLOSED); | |
188 | break; | |
189 | default: | |
190 | error("channel %d: protocol error: rcvd_ieof for ostate %d", | |
191 | c->self, c->ostate); | |
192 | break; | |
193 | } | |
194 | } | |
195 | static void | |
196 | chan_write_failed1(Channel *c) | |
197 | { | |
198 | debug2("channel %d: write failed", c->self); | |
199 | switch (c->ostate) { | |
200 | case CHAN_OUTPUT_OPEN: | |
201 | chan_shutdown_write(c); | |
202 | chan_send_oclose1(c); | |
203 | chan_set_ostate(c, CHAN_OUTPUT_WAIT_IEOF); | |
204 | break; | |
205 | case CHAN_OUTPUT_WAIT_DRAIN: | |
206 | chan_shutdown_write(c); | |
207 | chan_send_oclose1(c); | |
208 | chan_set_ostate(c, CHAN_OUTPUT_CLOSED); | |
209 | break; | |
210 | default: | |
211 | error("channel %d: chan_write_failed for ostate %d", | |
212 | c->self, c->ostate); | |
213 | break; | |
214 | } | |
215 | } | |
216 | void | |
217 | chan_obuf_empty(Channel *c) | |
218 | { | |
219 | debug2("channel %d: obuf empty", c->self); | |
220 | if (buffer_len(&c->output)) { | |
221 | error("channel %d: chan_obuf_empty for non empty buffer", | |
222 | c->self); | |
223 | return; | |
224 | } | |
225 | switch (c->ostate) { | |
226 | case CHAN_OUTPUT_WAIT_DRAIN: | |
227 | chan_shutdown_write(c); | |
228 | if (!compat20) | |
229 | chan_send_oclose1(c); | |
230 | chan_set_ostate(c, CHAN_OUTPUT_CLOSED); | |
231 | break; | |
232 | default: | |
233 | error("channel %d: internal error: obuf_empty for ostate %d", | |
234 | c->self, c->ostate); | |
235 | break; | |
236 | } | |
237 | } | |
238 | static void | |
239 | chan_send_ieof1(Channel *c) | |
240 | { | |
241 | debug2("channel %d: send ieof", c->self); | |
242 | switch (c->istate) { | |
243 | case CHAN_INPUT_OPEN: | |
244 | case CHAN_INPUT_WAIT_DRAIN: | |
245 | packet_start(SSH_MSG_CHANNEL_INPUT_EOF); | |
246 | packet_put_int(c->remote_id); | |
247 | packet_send(); | |
248 | break; | |
249 | default: | |
250 | error("channel %d: cannot send ieof for istate %d", | |
251 | c->self, c->istate); | |
252 | break; | |
253 | } | |
254 | } | |
255 | static void | |
256 | chan_send_oclose1(Channel *c) | |
257 | { | |
258 | debug2("channel %d: send oclose", c->self); | |
259 | switch (c->ostate) { | |
260 | case CHAN_OUTPUT_OPEN: | |
261 | case CHAN_OUTPUT_WAIT_DRAIN: | |
262 | buffer_clear(&c->output); | |
263 | packet_start(SSH_MSG_CHANNEL_OUTPUT_CLOSE); | |
264 | packet_put_int(c->remote_id); | |
265 | packet_send(); | |
266 | break; | |
267 | default: | |
268 | error("channel %d: cannot send oclose for ostate %d", | |
269 | c->self, c->ostate); | |
270 | break; | |
271 | } | |
272 | } | |
273 | ||
274 | /* | |
275 | * the same for SSH2 | |
276 | */ | |
277 | static void | |
278 | chan_rcvd_close2(Channel *c) | |
279 | { | |
280 | debug2("channel %d: rcvd close", c->self); | |
281 | if (c->flags & CHAN_CLOSE_RCVD) | |
282 | error("channel %d: protocol error: close rcvd twice", c->self); | |
283 | c->flags |= CHAN_CLOSE_RCVD; | |
284 | if (c->type == SSH_CHANNEL_LARVAL) { | |
285 | /* tear down larval channels immediately */ | |
286 | chan_set_ostate(c, CHAN_OUTPUT_CLOSED); | |
287 | chan_set_istate(c, CHAN_INPUT_CLOSED); | |
288 | return; | |
289 | } | |
290 | switch (c->ostate) { | |
291 | case CHAN_OUTPUT_OPEN: | |
292 | /* | |
293 | * wait until a data from the channel is consumed if a CLOSE | |
294 | * is received | |
295 | */ | |
296 | chan_set_ostate(c, CHAN_OUTPUT_WAIT_DRAIN); | |
297 | break; | |
298 | } | |
299 | switch (c->istate) { | |
300 | case CHAN_INPUT_OPEN: | |
301 | chan_shutdown_read(c); | |
302 | chan_set_istate(c, CHAN_INPUT_CLOSED); | |
303 | break; | |
304 | case CHAN_INPUT_WAIT_DRAIN: | |
305 | chan_send_eof2(c); | |
306 | chan_set_istate(c, CHAN_INPUT_CLOSED); | |
307 | break; | |
308 | } | |
309 | } | |
310 | void | |
311 | chan_rcvd_eow(Channel *c) | |
312 | { | |
313 | debug2("channel %d: rcvd eow", c->self); | |
314 | switch (c->istate) { | |
315 | case CHAN_INPUT_OPEN: | |
316 | chan_shutdown_read(c); | |
317 | chan_set_istate(c, CHAN_INPUT_CLOSED); | |
318 | break; | |
319 | } | |
320 | } | |
321 | static void | |
322 | chan_rcvd_eof2(Channel *c) | |
323 | { | |
324 | debug2("channel %d: rcvd eof", c->self); | |
325 | c->flags |= CHAN_EOF_RCVD; | |
326 | if (c->ostate == CHAN_OUTPUT_OPEN) | |
327 | chan_set_ostate(c, CHAN_OUTPUT_WAIT_DRAIN); | |
328 | } | |
329 | static void | |
330 | chan_write_failed2(Channel *c) | |
331 | { | |
332 | debug2("channel %d: write failed", c->self); | |
333 | switch (c->ostate) { | |
334 | case CHAN_OUTPUT_OPEN: | |
335 | case CHAN_OUTPUT_WAIT_DRAIN: | |
336 | chan_shutdown_write(c); | |
337 | if (strcmp(c->ctype, "session") == 0) | |
338 | chan_send_eow2(c); | |
339 | chan_set_ostate(c, CHAN_OUTPUT_CLOSED); | |
340 | break; | |
341 | default: | |
342 | error("channel %d: chan_write_failed for ostate %d", | |
343 | c->self, c->ostate); | |
344 | break; | |
345 | } | |
346 | } | |
347 | static void | |
348 | chan_send_eof2(Channel *c) | |
349 | { | |
350 | debug2("channel %d: send eof", c->self); | |
351 | switch (c->istate) { | |
352 | case CHAN_INPUT_WAIT_DRAIN: | |
353 | packet_start(SSH2_MSG_CHANNEL_EOF); | |
354 | packet_put_int(c->remote_id); | |
355 | packet_send(); | |
356 | c->flags |= CHAN_EOF_SENT; | |
357 | break; | |
358 | default: | |
359 | error("channel %d: cannot send eof for istate %d", | |
360 | c->self, c->istate); | |
361 | break; | |
362 | } | |
363 | } | |
364 | static void | |
365 | chan_send_close2(Channel *c) | |
366 | { | |
367 | debug2("channel %d: send close", c->self); | |
368 | if (c->ostate != CHAN_OUTPUT_CLOSED || | |
369 | c->istate != CHAN_INPUT_CLOSED) { | |
370 | error("channel %d: cannot send close for istate/ostate %d/%d", | |
371 | c->self, c->istate, c->ostate); | |
372 | } else if (c->flags & CHAN_CLOSE_SENT) { | |
373 | error("channel %d: already sent close", c->self); | |
374 | } else { | |
375 | packet_start(SSH2_MSG_CHANNEL_CLOSE); | |
376 | packet_put_int(c->remote_id); | |
377 | packet_send(); | |
378 | c->flags |= CHAN_CLOSE_SENT; | |
379 | } | |
380 | } | |
381 | static void | |
382 | chan_send_eow2(Channel *c) | |
383 | { | |
384 | debug2("channel %d: send eow", c->self); | |
385 | if (c->ostate == CHAN_OUTPUT_CLOSED) { | |
386 | error("channel %d: must not sent eow on closed output", | |
387 | c->self); | |
388 | return; | |
389 | } | |
390 | if (!(datafellows & SSH_NEW_OPENSSH)) | |
391 | return; | |
392 | packet_start(SSH2_MSG_CHANNEL_REQUEST); | |
393 | packet_put_int(c->remote_id); | |
394 | packet_put_cstring("eow@openssh.com"); | |
395 | packet_put_char(0); | |
396 | packet_send(); | |
397 | } | |
398 | ||
399 | /* shared */ | |
400 | ||
401 | void | |
402 | chan_rcvd_ieof(Channel *c) | |
403 | { | |
404 | if (compat20) | |
405 | chan_rcvd_eof2(c); | |
406 | else | |
407 | chan_rcvd_ieof1(c); | |
408 | if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN && | |
409 | buffer_len(&c->output) == 0 && | |
410 | !CHANNEL_EFD_OUTPUT_ACTIVE(c)) | |
411 | chan_obuf_empty(c); | |
412 | } | |
413 | void | |
414 | chan_rcvd_oclose(Channel *c) | |
415 | { | |
416 | if (compat20) | |
417 | chan_rcvd_close2(c); | |
418 | else | |
419 | chan_rcvd_oclose1(c); | |
420 | } | |
421 | void | |
422 | chan_write_failed(Channel *c) | |
423 | { | |
424 | if (compat20) | |
425 | chan_write_failed2(c); | |
426 | else | |
427 | chan_write_failed1(c); | |
428 | } | |
429 | ||
430 | void | |
431 | chan_mark_dead(Channel *c) | |
432 | { | |
433 | c->type = SSH_CHANNEL_ZOMBIE; | |
434 | } | |
435 | ||
436 | int | |
437 | chan_is_dead(Channel *c, int do_send) | |
438 | { | |
439 | if (c->type == SSH_CHANNEL_ZOMBIE) { | |
440 | debug2("channel %d: zombie", c->self); | |
441 | return 1; | |
442 | } | |
443 | if (c->istate != CHAN_INPUT_CLOSED || c->ostate != CHAN_OUTPUT_CLOSED) | |
444 | return 0; | |
445 | if (!compat20) { | |
446 | debug2("channel %d: is dead", c->self); | |
447 | return 1; | |
448 | } | |
449 | if ((datafellows & SSH_BUG_EXTEOF) && | |
450 | c->extended_usage == CHAN_EXTENDED_WRITE && | |
451 | c->efd != -1 && | |
452 | buffer_len(&c->extended) > 0) { | |
453 | debug2("channel %d: active efd: %d len %d", | |
454 | c->self, c->efd, buffer_len(&c->extended)); | |
455 | return 0; | |
456 | } | |
457 | if (!(c->flags & CHAN_CLOSE_SENT)) { | |
458 | if (do_send) { | |
459 | chan_send_close2(c); | |
460 | } else { | |
461 | /* channel would be dead if we sent a close */ | |
462 | if (c->flags & CHAN_CLOSE_RCVD) { | |
463 | debug2("channel %d: almost dead", | |
464 | c->self); | |
465 | return 1; | |
466 | } | |
467 | } | |
468 | } | |
469 | if ((c->flags & CHAN_CLOSE_SENT) && | |
470 | (c->flags & CHAN_CLOSE_RCVD)) { | |
471 | debug2("channel %d: is dead", c->self); | |
472 | return 1; | |
473 | } | |
474 | return 0; | |
475 | } | |
476 | ||
477 | /* helper */ | |
478 | static void | |
479 | chan_shutdown_write(Channel *c) | |
480 | { | |
481 | buffer_clear(&c->output); | |
482 | if (compat20 && c->type == SSH_CHANNEL_LARVAL) | |
483 | return; | |
484 | /* shutdown failure is allowed if write failed already */ | |
485 | debug2("channel %d: close_write", c->self); | |
486 | if (c->sock != -1) { | |
487 | if (shutdown(c->sock, SHUT_WR) < 0) | |
488 | debug2("channel %d: chan_shutdown_write: " | |
489 | "shutdown() failed for fd %d: %.100s", | |
490 | c->self, c->sock, strerror(errno)); | |
491 | } else { | |
492 | if (channel_close_fd(&c->wfd) < 0) | |
493 | logit("channel %d: chan_shutdown_write: " | |
494 | "close() failed for fd %d: %.100s", | |
495 | c->self, c->wfd, strerror(errno)); | |
496 | } | |
497 | } | |
498 | static void | |
499 | chan_shutdown_read(Channel *c) | |
500 | { | |
501 | if (compat20 && c->type == SSH_CHANNEL_LARVAL) | |
502 | return; | |
503 | debug2("channel %d: close_read", c->self); | |
504 | if (c->sock != -1) { | |
505 | /* | |
506 | * shutdown(sock, SHUT_READ) may return ENOTCONN if the | |
507 | * write side has been closed already. (bug on Linux) | |
508 | * HP-UX may return ENOTCONN also. | |
509 | */ | |
510 | if (shutdown(c->sock, SHUT_RD) < 0 | |
511 | && errno != ENOTCONN) | |
512 | error("channel %d: chan_shutdown_read: " | |
513 | "shutdown() failed for fd %d [i%d o%d]: %.100s", | |
514 | c->self, c->sock, c->istate, c->ostate, | |
515 | strerror(errno)); | |
516 | } else { | |
517 | if (channel_close_fd(&c->rfd) < 0) | |
518 | logit("channel %d: chan_shutdown_read: " | |
519 | "close() failed for fd %d: %.100s", | |
520 | c->self, c->rfd, strerror(errno)); | |
521 | } | |
522 | } |