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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 | * Created: Sun Sep 10 00:30:37 1995 ylo | |
6 | * Server main loop for handling the interactive session. | |
7 | */ | |
8 | /* | |
9 | * SSH2 support by Markus Friedl. | |
10 | * Copyright (c) 2000 Markus Friedl. All rights reserved. | |
11 | */ | |
12 | ||
13 | #include "includes.h" | |
14 | #include "xmalloc.h" | |
15 | #include "ssh.h" | |
16 | #include "packet.h" | |
17 | #include "buffer.h" | |
18 | #include "servconf.h" | |
19 | #include "pty.h" | |
20 | #include "channels.h" | |
21 | ||
22 | #include "compat.h" | |
23 | #include "ssh2.h" | |
24 | #include "session.h" | |
25 | #include "dispatch.h" | |
26 | #include "auth-options.h" | |
27 | ||
28 | static Buffer stdin_buffer; /* Buffer for stdin data. */ | |
29 | static Buffer stdout_buffer; /* Buffer for stdout data. */ | |
30 | static Buffer stderr_buffer; /* Buffer for stderr data. */ | |
31 | static int fdin; /* Descriptor for stdin (for writing) */ | |
32 | static int fdout; /* Descriptor for stdout (for reading); | |
33 | May be same number as fdin. */ | |
34 | static int fderr; /* Descriptor for stderr. May be -1. */ | |
35 | static long stdin_bytes = 0; /* Number of bytes written to stdin. */ | |
36 | static long stdout_bytes = 0; /* Number of stdout bytes sent to client. */ | |
37 | static long stderr_bytes = 0; /* Number of stderr bytes sent to client. */ | |
38 | static long fdout_bytes = 0; /* Number of stdout bytes read from program. */ | |
39 | static int stdin_eof = 0; /* EOF message received from client. */ | |
40 | static int fdout_eof = 0; /* EOF encountered reading from fdout. */ | |
41 | static int fderr_eof = 0; /* EOF encountered readung from fderr. */ | |
42 | static int connection_in; /* Connection to client (input). */ | |
43 | static int connection_out; /* Connection to client (output). */ | |
44 | static unsigned int buffer_high;/* "Soft" max buffer size. */ | |
45 | static int max_fd; /* Max file descriptor number for select(). */ | |
46 | ||
47 | /* | |
48 | * This SIGCHLD kludge is used to detect when the child exits. The server | |
49 | * will exit after that, as soon as forwarded connections have terminated. | |
50 | * | |
51 | * After SIGCHLD child_has_selected is set to 1 after the first pass | |
52 | * through the wait_until_can_do_something() select(). This ensures | |
53 | * that the child's output gets a chance to drain before it is yanked. | |
54 | */ | |
55 | ||
56 | static pid_t child_pid; /* Pid of the child. */ | |
57 | static volatile int child_terminated; /* The child has terminated. */ | |
58 | static volatile int child_has_selected; /* Child has had chance to drain. */ | |
59 | static volatile int child_wait_status; /* Status from wait(). */ | |
60 | ||
61 | void server_init_dispatch(void); | |
62 | ||
63 | void | |
64 | sigchld_handler(int sig) | |
65 | { | |
66 | int save_errno = errno; | |
67 | pid_t wait_pid; | |
68 | ||
69 | debug("Received SIGCHLD."); | |
70 | wait_pid = wait((int *) &child_wait_status); | |
71 | if (wait_pid != -1) { | |
72 | if (wait_pid != child_pid) | |
73 | error("Strange, got SIGCHLD and wait returned pid %d but child is %d", | |
74 | wait_pid, child_pid); | |
75 | if (WIFEXITED(child_wait_status) || | |
76 | WIFSIGNALED(child_wait_status)) | |
77 | child_terminated = 1; | |
78 | child_has_selected = 0; | |
79 | } | |
80 | signal(SIGCHLD, sigchld_handler); | |
81 | errno = save_errno; | |
82 | } | |
83 | void | |
84 | sigchld_handler2(int sig) | |
85 | { | |
86 | int save_errno = errno; | |
87 | debug("Received SIGCHLD."); | |
88 | child_terminated = 1; | |
89 | errno = save_errno; | |
90 | } | |
91 | ||
92 | /* | |
93 | * Make packets from buffered stderr data, and buffer it for sending | |
94 | * to the client. | |
95 | */ | |
96 | void | |
97 | make_packets_from_stderr_data() | |
98 | { | |
99 | int len; | |
100 | ||
101 | /* Send buffered stderr data to the client. */ | |
102 | while (buffer_len(&stderr_buffer) > 0 && | |
103 | packet_not_very_much_data_to_write()) { | |
104 | len = buffer_len(&stderr_buffer); | |
105 | if (packet_is_interactive()) { | |
106 | if (len > 512) | |
107 | len = 512; | |
108 | } else { | |
109 | /* Keep the packets at reasonable size. */ | |
110 | if (len > packet_get_maxsize()) | |
111 | len = packet_get_maxsize(); | |
112 | } | |
113 | packet_start(SSH_SMSG_STDERR_DATA); | |
114 | packet_put_string(buffer_ptr(&stderr_buffer), len); | |
115 | packet_send(); | |
116 | buffer_consume(&stderr_buffer, len); | |
117 | stderr_bytes += len; | |
118 | } | |
119 | } | |
120 | ||
121 | /* | |
122 | * Make packets from buffered stdout data, and buffer it for sending to the | |
123 | * client. | |
124 | */ | |
125 | void | |
126 | make_packets_from_stdout_data() | |
127 | { | |
128 | int len; | |
129 | ||
130 | /* Send buffered stdout data to the client. */ | |
131 | while (buffer_len(&stdout_buffer) > 0 && | |
132 | packet_not_very_much_data_to_write()) { | |
133 | len = buffer_len(&stdout_buffer); | |
134 | if (packet_is_interactive()) { | |
135 | if (len > 512) | |
136 | len = 512; | |
137 | } else { | |
138 | /* Keep the packets at reasonable size. */ | |
139 | if (len > packet_get_maxsize()) | |
140 | len = packet_get_maxsize(); | |
141 | } | |
142 | packet_start(SSH_SMSG_STDOUT_DATA); | |
143 | packet_put_string(buffer_ptr(&stdout_buffer), len); | |
144 | packet_send(); | |
145 | buffer_consume(&stdout_buffer, len); | |
146 | stdout_bytes += len; | |
147 | } | |
148 | } | |
149 | ||
150 | /* | |
151 | * Sleep in select() until we can do something. This will initialize the | |
152 | * select masks. Upon return, the masks will indicate which descriptors | |
153 | * have data or can accept data. Optionally, a maximum time can be specified | |
154 | * for the duration of the wait (0 = infinite). | |
155 | */ | |
156 | void | |
157 | wait_until_can_do_something(fd_set * readset, fd_set * writeset, | |
158 | unsigned int max_time_milliseconds) | |
159 | { | |
160 | struct timeval tv, *tvp; | |
161 | int ret; | |
162 | ||
163 | /* When select fails we restart from here. */ | |
164 | retry_select: | |
165 | ||
166 | /* Initialize select() masks. */ | |
167 | FD_ZERO(readset); | |
168 | FD_ZERO(writeset); | |
169 | ||
170 | if (compat20) { | |
171 | /* wrong: bad condition XXX */ | |
172 | if (channel_not_very_much_buffered_data()) | |
173 | FD_SET(connection_in, readset); | |
174 | } else { | |
175 | /* | |
176 | * Read packets from the client unless we have too much | |
177 | * buffered stdin or channel data. | |
178 | */ | |
179 | if (buffer_len(&stdin_buffer) < buffer_high && | |
180 | channel_not_very_much_buffered_data()) | |
181 | FD_SET(connection_in, readset); | |
182 | /* | |
183 | * If there is not too much data already buffered going to | |
184 | * the client, try to get some more data from the program. | |
185 | */ | |
186 | if (packet_not_very_much_data_to_write()) { | |
187 | if (!fdout_eof) | |
188 | FD_SET(fdout, readset); | |
189 | if (!fderr_eof) | |
190 | FD_SET(fderr, readset); | |
191 | } | |
192 | /* | |
193 | * If we have buffered data, try to write some of that data | |
194 | * to the program. | |
195 | */ | |
196 | if (fdin != -1 && buffer_len(&stdin_buffer) > 0) | |
197 | FD_SET(fdin, writeset); | |
198 | } | |
199 | /* Set masks for channel descriptors. */ | |
200 | channel_prepare_select(readset, writeset); | |
201 | ||
202 | /* | |
203 | * If we have buffered packet data going to the client, mark that | |
204 | * descriptor. | |
205 | */ | |
206 | if (packet_have_data_to_write()) | |
207 | FD_SET(connection_out, writeset); | |
208 | ||
209 | /* Update the maximum descriptor number if appropriate. */ | |
210 | if (channel_max_fd() > max_fd) | |
211 | max_fd = channel_max_fd(); | |
212 | ||
213 | /* | |
214 | * If child has terminated and there is enough buffer space to read | |
215 | * from it, then read as much as is available and exit. | |
216 | */ | |
217 | if (child_terminated && packet_not_very_much_data_to_write()) | |
218 | if (max_time_milliseconds == 0) | |
219 | max_time_milliseconds = 100; | |
220 | ||
221 | if (max_time_milliseconds == 0) | |
222 | tvp = NULL; | |
223 | else { | |
224 | tv.tv_sec = max_time_milliseconds / 1000; | |
225 | tv.tv_usec = 1000 * (max_time_milliseconds % 1000); | |
226 | tvp = &tv; | |
227 | } | |
228 | if (tvp!=NULL) | |
229 | debug("tvp!=NULL kid %d mili %d", child_terminated, max_time_milliseconds); | |
230 | ||
231 | /* Wait for something to happen, or the timeout to expire. */ | |
232 | ret = select(max_fd + 1, readset, writeset, NULL, tvp); | |
233 | ||
234 | if (ret < 0) { | |
235 | if (errno != EINTR) | |
236 | error("select: %.100s", strerror(errno)); | |
237 | else | |
238 | goto retry_select; | |
239 | } | |
240 | ||
241 | if (child_terminated) | |
242 | child_has_selected = 1; | |
243 | } | |
244 | ||
245 | /* | |
246 | * Processes input from the client and the program. Input data is stored | |
247 | * in buffers and processed later. | |
248 | */ | |
249 | void | |
250 | process_input(fd_set * readset) | |
251 | { | |
252 | int len; | |
253 | char buf[16384]; | |
254 | ||
255 | /* Read and buffer any input data from the client. */ | |
256 | if (FD_ISSET(connection_in, readset)) { | |
257 | len = read(connection_in, buf, sizeof(buf)); | |
258 | if (len == 0) { | |
259 | verbose("Connection closed by remote host."); | |
260 | fatal_cleanup(); | |
261 | } else if (len < 0) { | |
262 | if (errno != EINTR && errno != EAGAIN) { | |
263 | verbose("Read error from remote host: %.100s", strerror(errno)); | |
264 | fatal_cleanup(); | |
265 | } | |
266 | } else { | |
267 | /* Buffer any received data. */ | |
268 | packet_process_incoming(buf, len); | |
269 | } | |
270 | } | |
271 | if (compat20) | |
272 | return; | |
273 | ||
274 | /* Read and buffer any available stdout data from the program. */ | |
275 | if (!fdout_eof && FD_ISSET(fdout, readset)) { | |
276 | len = read(fdout, buf, sizeof(buf)); | |
277 | if (len < 0 && (errno == EINTR || errno == EAGAIN)) { | |
278 | /* do nothing */ | |
279 | } else if (len <= 0) { | |
280 | fdout_eof = 1; | |
281 | } else { | |
282 | buffer_append(&stdout_buffer, buf, len); | |
283 | fdout_bytes += len; | |
284 | } | |
285 | } | |
286 | /* Read and buffer any available stderr data from the program. */ | |
287 | if (!fderr_eof && FD_ISSET(fderr, readset)) { | |
288 | len = read(fderr, buf, sizeof(buf)); | |
289 | if (len < 0 && (errno == EINTR || errno == EAGAIN)) { | |
290 | /* do nothing */ | |
291 | } else if (len <= 0) { | |
292 | fderr_eof = 1; | |
293 | } else { | |
294 | buffer_append(&stderr_buffer, buf, len); | |
295 | } | |
296 | } | |
297 | } | |
298 | ||
299 | /* | |
300 | * Sends data from internal buffers to client program stdin. | |
301 | */ | |
302 | void | |
303 | process_output(fd_set * writeset) | |
304 | { | |
305 | int len; | |
306 | ||
307 | /* Write buffered data to program stdin. */ | |
308 | if (!compat20 && fdin != -1 && FD_ISSET(fdin, writeset)) { | |
309 | len = write(fdin, buffer_ptr(&stdin_buffer), | |
310 | buffer_len(&stdin_buffer)); | |
311 | if (len < 0 && (errno == EINTR || errno == EAGAIN)) { | |
312 | /* do nothing */ | |
313 | } else if (len <= 0) { | |
314 | #ifdef USE_PIPES | |
315 | close(fdin); | |
316 | #else | |
317 | if (fdin != fdout) | |
318 | close(fdin); | |
319 | else | |
320 | shutdown(fdin, SHUT_WR); /* We will no longer send. */ | |
321 | #endif | |
322 | fdin = -1; | |
323 | } else { | |
324 | /* Successful write. Consume the data from the buffer. */ | |
325 | buffer_consume(&stdin_buffer, len); | |
326 | /* Update the count of bytes written to the program. */ | |
327 | stdin_bytes += len; | |
328 | } | |
329 | } | |
330 | /* Send any buffered packet data to the client. */ | |
331 | if (FD_ISSET(connection_out, writeset)) | |
332 | packet_write_poll(); | |
333 | } | |
334 | ||
335 | /* | |
336 | * Wait until all buffered output has been sent to the client. | |
337 | * This is used when the program terminates. | |
338 | */ | |
339 | void | |
340 | drain_output() | |
341 | { | |
342 | /* Send any buffered stdout data to the client. */ | |
343 | if (buffer_len(&stdout_buffer) > 0) { | |
344 | packet_start(SSH_SMSG_STDOUT_DATA); | |
345 | packet_put_string(buffer_ptr(&stdout_buffer), | |
346 | buffer_len(&stdout_buffer)); | |
347 | packet_send(); | |
348 | /* Update the count of sent bytes. */ | |
349 | stdout_bytes += buffer_len(&stdout_buffer); | |
350 | } | |
351 | /* Send any buffered stderr data to the client. */ | |
352 | if (buffer_len(&stderr_buffer) > 0) { | |
353 | packet_start(SSH_SMSG_STDERR_DATA); | |
354 | packet_put_string(buffer_ptr(&stderr_buffer), | |
355 | buffer_len(&stderr_buffer)); | |
356 | packet_send(); | |
357 | /* Update the count of sent bytes. */ | |
358 | stderr_bytes += buffer_len(&stderr_buffer); | |
359 | } | |
360 | /* Wait until all buffered data has been written to the client. */ | |
361 | packet_write_wait(); | |
362 | } | |
363 | ||
364 | void | |
365 | process_buffered_input_packets() | |
366 | { | |
367 | dispatch_run(DISPATCH_NONBLOCK, NULL); | |
368 | } | |
369 | ||
370 | /* | |
371 | * Performs the interactive session. This handles data transmission between | |
372 | * the client and the program. Note that the notion of stdin, stdout, and | |
373 | * stderr in this function is sort of reversed: this function writes to | |
374 | * stdin (of the child program), and reads from stdout and stderr (of the | |
375 | * child program). | |
376 | */ | |
377 | void | |
378 | server_loop(pid_t pid, int fdin_arg, int fdout_arg, int fderr_arg) | |
379 | { | |
380 | fd_set readset, writeset; | |
381 | int wait_status; /* Status returned by wait(). */ | |
382 | pid_t wait_pid; /* pid returned by wait(). */ | |
383 | int waiting_termination = 0; /* Have displayed waiting close message. */ | |
384 | unsigned int max_time_milliseconds; | |
385 | unsigned int previous_stdout_buffer_bytes; | |
386 | unsigned int stdout_buffer_bytes; | |
387 | int type; | |
388 | ||
389 | debug("Entering interactive session."); | |
390 | ||
391 | /* Initialize the SIGCHLD kludge. */ | |
392 | child_pid = pid; | |
393 | child_terminated = 0; | |
394 | child_has_selected = 0; | |
395 | signal(SIGCHLD, sigchld_handler); | |
396 | ||
397 | /* Initialize our global variables. */ | |
398 | fdin = fdin_arg; | |
399 | fdout = fdout_arg; | |
400 | fderr = fderr_arg; | |
401 | ||
402 | /* nonblocking IO */ | |
403 | set_nonblock(fdin); | |
404 | set_nonblock(fdout); | |
405 | /* we don't have stderr for interactive terminal sessions, see below */ | |
406 | if (fderr != -1) | |
407 | set_nonblock(fderr); | |
408 | ||
409 | connection_in = packet_get_connection_in(); | |
410 | connection_out = packet_get_connection_out(); | |
411 | ||
412 | previous_stdout_buffer_bytes = 0; | |
413 | ||
414 | /* Set approximate I/O buffer size. */ | |
415 | if (packet_is_interactive()) | |
416 | buffer_high = 4096; | |
417 | else | |
418 | buffer_high = 64 * 1024; | |
419 | ||
420 | /* Initialize max_fd to the maximum of the known file descriptors. */ | |
421 | max_fd = fdin; | |
422 | if (fdout > max_fd) | |
423 | max_fd = fdout; | |
424 | if (fderr != -1 && fderr > max_fd) | |
425 | max_fd = fderr; | |
426 | if (connection_in > max_fd) | |
427 | max_fd = connection_in; | |
428 | if (connection_out > max_fd) | |
429 | max_fd = connection_out; | |
430 | ||
431 | /* Initialize Initialize buffers. */ | |
432 | buffer_init(&stdin_buffer); | |
433 | buffer_init(&stdout_buffer); | |
434 | buffer_init(&stderr_buffer); | |
435 | ||
436 | /* | |
437 | * If we have no separate fderr (which is the case when we have a pty | |
438 | * - there we cannot make difference between data sent to stdout and | |
439 | * stderr), indicate that we have seen an EOF from stderr. This way | |
440 | * we don\'t need to check the descriptor everywhere. | |
441 | */ | |
442 | if (fderr == -1) | |
443 | fderr_eof = 1; | |
444 | ||
445 | server_init_dispatch(); | |
446 | ||
447 | /* Main loop of the server for the interactive session mode. */ | |
448 | for (;;) { | |
449 | ||
450 | /* Process buffered packets from the client. */ | |
451 | process_buffered_input_packets(); | |
452 | ||
453 | /* | |
454 | * If we have received eof, and there is no more pending | |
455 | * input data, cause a real eof by closing fdin. | |
456 | */ | |
457 | if (stdin_eof && fdin != -1 && buffer_len(&stdin_buffer) == 0) { | |
458 | #ifdef USE_PIPES | |
459 | close(fdin); | |
460 | #else | |
461 | if (fdin != fdout) | |
462 | close(fdin); | |
463 | else | |
464 | shutdown(fdin, SHUT_WR); /* We will no longer send. */ | |
465 | #endif | |
466 | fdin = -1; | |
467 | } | |
468 | /* Make packets from buffered stderr data to send to the client. */ | |
469 | make_packets_from_stderr_data(); | |
470 | ||
471 | /* | |
472 | * Make packets from buffered stdout data to send to the | |
473 | * client. If there is very little to send, this arranges to | |
474 | * not send them now, but to wait a short while to see if we | |
475 | * are getting more data. This is necessary, as some systems | |
476 | * wake up readers from a pty after each separate character. | |
477 | */ | |
478 | max_time_milliseconds = 0; | |
479 | stdout_buffer_bytes = buffer_len(&stdout_buffer); | |
480 | if (stdout_buffer_bytes != 0 && stdout_buffer_bytes < 256 && | |
481 | stdout_buffer_bytes != previous_stdout_buffer_bytes) { | |
482 | /* try again after a while */ | |
483 | max_time_milliseconds = 10; | |
484 | } else { | |
485 | /* Send it now. */ | |
486 | make_packets_from_stdout_data(); | |
487 | } | |
488 | previous_stdout_buffer_bytes = buffer_len(&stdout_buffer); | |
489 | ||
490 | /* Send channel data to the client. */ | |
491 | if (packet_not_very_much_data_to_write()) | |
492 | channel_output_poll(); | |
493 | ||
494 | /* | |
495 | * Bail out of the loop if the program has closed its output | |
496 | * descriptors, and we have no more data to send to the | |
497 | * client, and there is no pending buffered data. | |
498 | */ | |
499 | if (((fdout_eof && fderr_eof) || | |
500 | (child_terminated && child_has_selected)) && | |
501 | !packet_have_data_to_write() && | |
502 | (buffer_len(&stdout_buffer) == 0) && | |
503 | (buffer_len(&stderr_buffer) == 0)) { | |
504 | if (!channel_still_open()) | |
505 | break; | |
506 | if (!waiting_termination) { | |
507 | const char *s = "Waiting for forwarded connections to terminate...\r\n"; | |
508 | char *cp; | |
509 | waiting_termination = 1; | |
510 | buffer_append(&stderr_buffer, s, strlen(s)); | |
511 | ||
512 | /* Display list of open channels. */ | |
513 | cp = channel_open_message(); | |
514 | buffer_append(&stderr_buffer, cp, strlen(cp)); | |
515 | xfree(cp); | |
516 | } | |
517 | } | |
518 | /* Sleep in select() until we can do something. */ | |
519 | wait_until_can_do_something(&readset, &writeset, | |
520 | max_time_milliseconds); | |
521 | ||
522 | /* Process any channel events. */ | |
523 | channel_after_select(&readset, &writeset); | |
524 | ||
525 | /* Process input from the client and from program stdout/stderr. */ | |
526 | process_input(&readset); | |
527 | ||
528 | /* Process output to the client and to program stdin. */ | |
529 | process_output(&writeset); | |
530 | } | |
531 | ||
532 | /* Cleanup and termination code. */ | |
533 | ||
534 | /* Wait until all output has been sent to the client. */ | |
535 | drain_output(); | |
536 | ||
537 | debug("End of interactive session; stdin %ld, stdout (read %ld, sent %ld), stderr %ld bytes.", | |
538 | stdin_bytes, fdout_bytes, stdout_bytes, stderr_bytes); | |
539 | ||
540 | /* Free and clear the buffers. */ | |
541 | buffer_free(&stdin_buffer); | |
542 | buffer_free(&stdout_buffer); | |
543 | buffer_free(&stderr_buffer); | |
544 | ||
545 | /* Close the file descriptors. */ | |
546 | if (fdout != -1) | |
547 | close(fdout); | |
548 | fdout = -1; | |
549 | fdout_eof = 1; | |
550 | if (fderr != -1) | |
551 | close(fderr); | |
552 | fderr = -1; | |
553 | fderr_eof = 1; | |
554 | if (fdin != -1) | |
555 | close(fdin); | |
556 | fdin = -1; | |
557 | ||
558 | /* Stop listening for channels; this removes unix domain sockets. */ | |
559 | channel_stop_listening(); | |
560 | ||
561 | /* Wait for the child to exit. Get its exit status. */ | |
562 | wait_pid = wait(&wait_status); | |
563 | if (wait_pid < 0) { | |
564 | /* | |
565 | * It is possible that the wait was handled by SIGCHLD | |
566 | * handler. This may result in either: this call | |
567 | * returning with EINTR, or: this call returning ECHILD. | |
568 | */ | |
569 | if (child_terminated) | |
570 | wait_status = child_wait_status; | |
571 | else | |
572 | packet_disconnect("wait: %.100s", strerror(errno)); | |
573 | } else { | |
574 | /* Check if it matches the process we forked. */ | |
575 | if (wait_pid != pid) | |
576 | error("Strange, wait returned pid %d, expected %d", | |
577 | wait_pid, pid); | |
578 | } | |
579 | ||
580 | /* We no longer want our SIGCHLD handler to be called. */ | |
581 | signal(SIGCHLD, SIG_DFL); | |
582 | ||
583 | /* Check if it exited normally. */ | |
584 | if (WIFEXITED(wait_status)) { | |
585 | /* Yes, normal exit. Get exit status and send it to the client. */ | |
586 | debug("Command exited with status %d.", WEXITSTATUS(wait_status)); | |
587 | packet_start(SSH_SMSG_EXITSTATUS); | |
588 | packet_put_int(WEXITSTATUS(wait_status)); | |
589 | packet_send(); | |
590 | packet_write_wait(); | |
591 | ||
592 | /* | |
593 | * Wait for exit confirmation. Note that there might be | |
594 | * other packets coming before it; however, the program has | |
595 | * already died so we just ignore them. The client is | |
596 | * supposed to respond with the confirmation when it receives | |
597 | * the exit status. | |
598 | */ | |
599 | do { | |
600 | int plen; | |
601 | type = packet_read(&plen); | |
602 | } | |
603 | while (type != SSH_CMSG_EXIT_CONFIRMATION); | |
604 | ||
605 | debug("Received exit confirmation."); | |
606 | return; | |
607 | } | |
608 | /* Check if the program terminated due to a signal. */ | |
609 | if (WIFSIGNALED(wait_status)) | |
610 | packet_disconnect("Command terminated on signal %d.", | |
611 | WTERMSIG(wait_status)); | |
612 | ||
613 | /* Some weird exit cause. Just exit. */ | |
614 | packet_disconnect("wait returned status %04x.", wait_status); | |
615 | /* NOTREACHED */ | |
616 | } | |
617 | ||
618 | void | |
619 | server_loop2(void) | |
620 | { | |
621 | fd_set readset, writeset; | |
622 | int had_channel = 0; | |
623 | int status; | |
624 | pid_t pid; | |
625 | ||
626 | debug("Entering interactive session for SSH2."); | |
627 | ||
628 | signal(SIGCHLD, sigchld_handler2); | |
629 | child_terminated = 0; | |
630 | connection_in = packet_get_connection_in(); | |
631 | connection_out = packet_get_connection_out(); | |
632 | max_fd = connection_in; | |
633 | if (connection_out > max_fd) | |
634 | max_fd = connection_out; | |
635 | server_init_dispatch(); | |
636 | ||
637 | for (;;) { | |
638 | process_buffered_input_packets(); | |
639 | if (!had_channel && channel_still_open()) | |
640 | had_channel = 1; | |
641 | if (had_channel && !channel_still_open()) { | |
642 | debug("!channel_still_open."); | |
643 | break; | |
644 | } | |
645 | if (packet_not_very_much_data_to_write()) | |
646 | channel_output_poll(); | |
647 | wait_until_can_do_something(&readset, &writeset, 0); | |
648 | if (child_terminated) { | |
649 | while ((pid = waitpid(-1, &status, WNOHANG)) > 0) | |
650 | session_close_by_pid(pid, status); | |
651 | child_terminated = 0; | |
652 | signal(SIGCHLD, sigchld_handler2); | |
653 | } | |
654 | channel_after_select(&readset, &writeset); | |
655 | process_input(&readset); | |
656 | process_output(&writeset); | |
657 | } | |
658 | signal(SIGCHLD, SIG_DFL); | |
659 | while ((pid = waitpid(-1, &status, WNOHANG)) > 0) | |
660 | session_close_by_pid(pid, status); | |
661 | channel_stop_listening(); | |
662 | } | |
663 | ||
664 | void | |
665 | server_input_stdin_data(int type, int plen) | |
666 | { | |
667 | char *data; | |
668 | unsigned int data_len; | |
669 | ||
670 | /* Stdin data from the client. Append it to the buffer. */ | |
671 | /* Ignore any data if the client has closed stdin. */ | |
672 | if (fdin == -1) | |
673 | return; | |
674 | data = packet_get_string(&data_len); | |
675 | packet_integrity_check(plen, (4 + data_len), type); | |
676 | buffer_append(&stdin_buffer, data, data_len); | |
677 | memset(data, 0, data_len); | |
678 | xfree(data); | |
679 | } | |
680 | ||
681 | void | |
682 | server_input_eof(int type, int plen) | |
683 | { | |
684 | /* | |
685 | * Eof from the client. The stdin descriptor to the | |
686 | * program will be closed when all buffered data has | |
687 | * drained. | |
688 | */ | |
689 | debug("EOF received for stdin."); | |
690 | packet_integrity_check(plen, 0, type); | |
691 | stdin_eof = 1; | |
692 | } | |
693 | ||
694 | void | |
695 | server_input_window_size(int type, int plen) | |
696 | { | |
697 | int row = packet_get_int(); | |
698 | int col = packet_get_int(); | |
699 | int xpixel = packet_get_int(); | |
700 | int ypixel = packet_get_int(); | |
701 | ||
702 | debug("Window change received."); | |
703 | packet_integrity_check(plen, 4 * 4, type); | |
704 | if (fdin != -1) | |
705 | pty_change_window_size(fdin, row, col, xpixel, ypixel); | |
706 | } | |
707 | ||
708 | int | |
709 | input_direct_tcpip(void) | |
710 | { | |
711 | int sock; | |
712 | char *target, *originator; | |
713 | int target_port, originator_port; | |
714 | ||
715 | target = packet_get_string(NULL); | |
716 | target_port = packet_get_int(); | |
717 | originator = packet_get_string(NULL); | |
718 | originator_port = packet_get_int(); | |
719 | packet_done(); | |
720 | ||
721 | debug("open direct-tcpip: from %s port %d to %s port %d", | |
722 | originator, originator_port, target, target_port); | |
723 | ||
724 | /* XXX check permission */ | |
725 | if (! no_port_forwarding_flag) { | |
726 | xfree(target); | |
727 | xfree(originator); | |
728 | return -1; | |
729 | } | |
730 | sock = channel_connect_to(target, target_port); | |
731 | xfree(target); | |
732 | xfree(originator); | |
733 | if (sock < 0) | |
734 | return -1; | |
735 | return channel_new("direct-tcpip", SSH_CHANNEL_OPEN, | |
736 | sock, sock, -1, 4*1024, 32*1024, 0, xstrdup("direct-tcpip")); | |
737 | } | |
738 | ||
739 | void | |
740 | server_input_channel_open(int type, int plen) | |
741 | { | |
742 | Channel *c = NULL; | |
743 | char *ctype; | |
744 | int id; | |
745 | unsigned int len; | |
746 | int rchan; | |
747 | int rmaxpack; | |
748 | int rwindow; | |
749 | ||
750 | ctype = packet_get_string(&len); | |
751 | rchan = packet_get_int(); | |
752 | rwindow = packet_get_int(); | |
753 | rmaxpack = packet_get_int(); | |
754 | ||
755 | debug("channel_input_open: ctype %s rchan %d win %d max %d", | |
756 | ctype, rchan, rwindow, rmaxpack); | |
757 | ||
758 | if (strcmp(ctype, "session") == 0) { | |
759 | debug("open session"); | |
760 | packet_done(); | |
761 | /* | |
762 | * A server session has no fd to read or write | |
763 | * until a CHANNEL_REQUEST for a shell is made, | |
764 | * so we set the type to SSH_CHANNEL_LARVAL. | |
765 | * Additionally, a callback for handling all | |
766 | * CHANNEL_REQUEST messages is registered. | |
767 | */ | |
768 | id = channel_new(ctype, SSH_CHANNEL_LARVAL, | |
769 | -1, -1, -1, 0, 32*1024, 0, xstrdup("server-session")); | |
770 | if (session_open(id) == 1) { | |
771 | channel_register_callback(id, SSH2_MSG_CHANNEL_REQUEST, | |
772 | session_input_channel_req, (void *)0); | |
773 | channel_register_cleanup(id, session_close_by_channel); | |
774 | c = channel_lookup(id); | |
775 | } else { | |
776 | debug("session open failed, free channel %d", id); | |
777 | channel_free(id); | |
778 | } | |
779 | } else if (strcmp(ctype, "direct-tcpip") == 0) { | |
780 | id = input_direct_tcpip(); | |
781 | if (id >= 0) | |
782 | c = channel_lookup(id); | |
783 | } | |
784 | if (c != NULL) { | |
785 | debug("confirm %s", ctype); | |
786 | c->remote_id = rchan; | |
787 | c->remote_window = rwindow; | |
788 | c->remote_maxpacket = rmaxpack; | |
789 | ||
790 | packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION); | |
791 | packet_put_int(c->remote_id); | |
792 | packet_put_int(c->self); | |
793 | packet_put_int(c->local_window); | |
794 | packet_put_int(c->local_maxpacket); | |
795 | packet_send(); | |
796 | } else { | |
797 | debug("failure %s", ctype); | |
798 | packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE); | |
799 | packet_put_int(rchan); | |
800 | packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED); | |
801 | packet_put_cstring("bla bla"); | |
802 | packet_put_cstring(""); | |
803 | packet_send(); | |
804 | } | |
805 | xfree(ctype); | |
806 | } | |
807 | ||
808 | void | |
809 | server_init_dispatch_20() | |
810 | { | |
811 | debug("server_init_dispatch_20"); | |
812 | dispatch_init(&dispatch_protocol_error); | |
813 | dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose); | |
814 | dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data); | |
815 | dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof); | |
816 | dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data); | |
817 | dispatch_set(SSH2_MSG_CHANNEL_OPEN, &server_input_channel_open); | |
818 | dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); | |
819 | dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); | |
820 | dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &channel_input_channel_request); | |
821 | dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust); | |
822 | } | |
823 | void | |
824 | server_init_dispatch_13() | |
825 | { | |
826 | debug("server_init_dispatch_13"); | |
827 | dispatch_init(NULL); | |
828 | dispatch_set(SSH_CMSG_EOF, &server_input_eof); | |
829 | dispatch_set(SSH_CMSG_STDIN_DATA, &server_input_stdin_data); | |
830 | dispatch_set(SSH_CMSG_WINDOW_SIZE, &server_input_window_size); | |
831 | dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close); | |
832 | dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation); | |
833 | dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data); | |
834 | dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); | |
835 | dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); | |
836 | dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open); | |
837 | } | |
838 | void | |
839 | server_init_dispatch_15() | |
840 | { | |
841 | server_init_dispatch_13(); | |
842 | debug("server_init_dispatch_15"); | |
843 | dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof); | |
844 | dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_oclose); | |
845 | } | |
846 | void | |
847 | server_init_dispatch() | |
848 | { | |
849 | if (compat20) | |
850 | server_init_dispatch_20(); | |
851 | else if (compat13) | |
852 | server_init_dispatch_13(); | |
853 | else | |
854 | server_init_dispatch_15(); | |
855 | } |