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8efc0c15 | 1 | /* |
5260325f | 2 | * Author: Tatu Ylonen <ylo@cs.hut.fi> |
3 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland | |
4 | * All rights reserved | |
5260325f | 5 | * Server main loop for handling the interactive session. |
bcbf86ec | 6 | * |
7 | * As far as I am concerned, the code I have written for this software | |
8 | * can be used freely for any purpose. Any derived versions of this | |
9 | * software must be clearly marked as such, and if the derived work is | |
10 | * incompatible with the protocol description in the RFC file, it must be | |
11 | * called by a name other than "ssh" or "Secure Shell". | |
12 | * | |
e78a59f5 | 13 | * SSH2 support by Markus Friedl. |
14 | * Copyright (c) 2000 Markus Friedl. All rights reserved. | |
bcbf86ec | 15 | * |
16 | * Redistribution and use in source and binary forms, with or without | |
17 | * modification, are permitted provided that the following conditions | |
18 | * are met: | |
19 | * 1. Redistributions of source code must retain the above copyright | |
20 | * notice, this list of conditions and the following disclaimer. | |
21 | * 2. Redistributions in binary form must reproduce the above copyright | |
22 | * notice, this list of conditions and the following disclaimer in the | |
23 | * documentation and/or other materials provided with the distribution. | |
24 | * | |
25 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR | |
26 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES | |
27 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. | |
28 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, | |
29 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | |
30 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
31 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
32 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
33 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF | |
34 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
e78a59f5 | 35 | */ |
8efc0c15 | 36 | |
37 | #include "includes.h" | |
a22aff1f | 38 | RCSID("$OpenBSD: serverloop.c,v 1.34 2000/10/27 07:32:18 markus Exp $"); |
39 | ||
8efc0c15 | 40 | #include "xmalloc.h" |
41 | #include "ssh.h" | |
42 | #include "packet.h" | |
43 | #include "buffer.h" | |
44 | #include "servconf.h" | |
45 | #include "pty.h" | |
7368a6c8 | 46 | #include "channels.h" |
47 | ||
48 | #include "compat.h" | |
e78a59f5 | 49 | #include "ssh2.h" |
50 | #include "session.h" | |
7368a6c8 | 51 | #include "dispatch.h" |
38c295d6 | 52 | #include "auth-options.h" |
8efc0c15 | 53 | |
33de75a3 | 54 | extern ServerOptions options; |
55 | ||
8efc0c15 | 56 | static Buffer stdin_buffer; /* Buffer for stdin data. */ |
57 | static Buffer stdout_buffer; /* Buffer for stdout data. */ | |
58 | static Buffer stderr_buffer; /* Buffer for stderr data. */ | |
59 | static int fdin; /* Descriptor for stdin (for writing) */ | |
60 | static int fdout; /* Descriptor for stdout (for reading); | |
61 | May be same number as fdin. */ | |
62 | static int fderr; /* Descriptor for stderr. May be -1. */ | |
63 | static long stdin_bytes = 0; /* Number of bytes written to stdin. */ | |
64 | static long stdout_bytes = 0; /* Number of stdout bytes sent to client. */ | |
65 | static long stderr_bytes = 0; /* Number of stderr bytes sent to client. */ | |
66 | static long fdout_bytes = 0; /* Number of stdout bytes read from program. */ | |
67 | static int stdin_eof = 0; /* EOF message received from client. */ | |
68 | static int fdout_eof = 0; /* EOF encountered reading from fdout. */ | |
69 | static int fderr_eof = 0; /* EOF encountered readung from fderr. */ | |
70 | static int connection_in; /* Connection to client (input). */ | |
71 | static int connection_out; /* Connection to client (output). */ | |
72 | static unsigned int buffer_high;/* "Soft" max buffer size. */ | |
73 | static int max_fd; /* Max file descriptor number for select(). */ | |
74 | ||
aa3378df | 75 | /* |
76 | * This SIGCHLD kludge is used to detect when the child exits. The server | |
77 | * will exit after that, as soon as forwarded connections have terminated. | |
691a8a9f | 78 | * |
79 | * After SIGCHLD child_has_selected is set to 1 after the first pass | |
80 | * through the wait_until_can_do_something() select(). This ensures | |
81 | * that the child's output gets a chance to drain before it is yanked. | |
aa3378df | 82 | */ |
8efc0c15 | 83 | |
9da5c3c9 | 84 | static pid_t child_pid; /* Pid of the child. */ |
8efc0c15 | 85 | static volatile int child_terminated; /* The child has terminated. */ |
691a8a9f | 86 | static volatile int child_has_selected; /* Child has had chance to drain. */ |
8efc0c15 | 87 | static volatile int child_wait_status; /* Status from wait(). */ |
88 | ||
7368a6c8 | 89 | void server_init_dispatch(void); |
90 | ||
6ae2364d | 91 | void |
5260325f | 92 | sigchld_handler(int sig) |
8efc0c15 | 93 | { |
5260325f | 94 | int save_errno = errno; |
9da5c3c9 | 95 | pid_t wait_pid; |
96 | ||
5260325f | 97 | debug("Received SIGCHLD."); |
98 | wait_pid = wait((int *) &child_wait_status); | |
99 | if (wait_pid != -1) { | |
100 | if (wait_pid != child_pid) | |
101 | error("Strange, got SIGCHLD and wait returned pid %d but child is %d", | |
102 | wait_pid, child_pid); | |
103 | if (WIFEXITED(child_wait_status) || | |
344f2b94 | 104 | WIFSIGNALED(child_wait_status)) { |
5260325f | 105 | child_terminated = 1; |
691a8a9f | 106 | child_has_selected = 0; |
344f2b94 | 107 | } |
5260325f | 108 | } |
109 | signal(SIGCHLD, sigchld_handler); | |
110 | errno = save_errno; | |
8efc0c15 | 111 | } |
6ae2364d | 112 | void |
e78a59f5 | 113 | sigchld_handler2(int sig) |
114 | { | |
115 | int save_errno = errno; | |
116 | debug("Received SIGCHLD."); | |
117 | child_terminated = 1; | |
344f2b94 | 118 | child_has_selected = 0; |
e78a59f5 | 119 | errno = save_errno; |
120 | } | |
8efc0c15 | 121 | |
5260325f | 122 | /* |
123 | * Make packets from buffered stderr data, and buffer it for sending | |
124 | * to the client. | |
125 | */ | |
6ae2364d | 126 | void |
5260325f | 127 | make_packets_from_stderr_data() |
8efc0c15 | 128 | { |
5260325f | 129 | int len; |
130 | ||
131 | /* Send buffered stderr data to the client. */ | |
132 | while (buffer_len(&stderr_buffer) > 0 && | |
a408af76 | 133 | packet_not_very_much_data_to_write()) { |
5260325f | 134 | len = buffer_len(&stderr_buffer); |
135 | if (packet_is_interactive()) { | |
136 | if (len > 512) | |
137 | len = 512; | |
138 | } else { | |
139 | /* Keep the packets at reasonable size. */ | |
140 | if (len > packet_get_maxsize()) | |
141 | len = packet_get_maxsize(); | |
142 | } | |
143 | packet_start(SSH_SMSG_STDERR_DATA); | |
144 | packet_put_string(buffer_ptr(&stderr_buffer), len); | |
145 | packet_send(); | |
146 | buffer_consume(&stderr_buffer, len); | |
147 | stderr_bytes += len; | |
8efc0c15 | 148 | } |
8efc0c15 | 149 | } |
150 | ||
5260325f | 151 | /* |
152 | * Make packets from buffered stdout data, and buffer it for sending to the | |
153 | * client. | |
154 | */ | |
6ae2364d | 155 | void |
5260325f | 156 | make_packets_from_stdout_data() |
8efc0c15 | 157 | { |
5260325f | 158 | int len; |
159 | ||
160 | /* Send buffered stdout data to the client. */ | |
161 | while (buffer_len(&stdout_buffer) > 0 && | |
a408af76 | 162 | packet_not_very_much_data_to_write()) { |
5260325f | 163 | len = buffer_len(&stdout_buffer); |
164 | if (packet_is_interactive()) { | |
165 | if (len > 512) | |
166 | len = 512; | |
167 | } else { | |
168 | /* Keep the packets at reasonable size. */ | |
169 | if (len > packet_get_maxsize()) | |
170 | len = packet_get_maxsize(); | |
171 | } | |
172 | packet_start(SSH_SMSG_STDOUT_DATA); | |
173 | packet_put_string(buffer_ptr(&stdout_buffer), len); | |
174 | packet_send(); | |
175 | buffer_consume(&stdout_buffer, len); | |
176 | stdout_bytes += len; | |
8efc0c15 | 177 | } |
8efc0c15 | 178 | } |
179 | ||
5260325f | 180 | /* |
181 | * Sleep in select() until we can do something. This will initialize the | |
182 | * select masks. Upon return, the masks will indicate which descriptors | |
183 | * have data or can accept data. Optionally, a maximum time can be specified | |
184 | * for the duration of the wait (0 = infinite). | |
185 | */ | |
6ae2364d | 186 | void |
5260325f | 187 | wait_until_can_do_something(fd_set * readset, fd_set * writeset, |
188 | unsigned int max_time_milliseconds) | |
8efc0c15 | 189 | { |
5260325f | 190 | struct timeval tv, *tvp; |
191 | int ret; | |
8efc0c15 | 192 | |
5260325f | 193 | /* When select fails we restart from here. */ |
8efc0c15 | 194 | retry_select: |
195 | ||
5260325f | 196 | /* Initialize select() masks. */ |
197 | FD_ZERO(readset); | |
71276795 | 198 | FD_ZERO(writeset); |
5260325f | 199 | |
e78a59f5 | 200 | if (compat20) { |
1d1ffb87 | 201 | /* wrong: bad condition XXX */ |
e78a59f5 | 202 | if (channel_not_very_much_buffered_data()) |
203 | FD_SET(connection_in, readset); | |
204 | } else { | |
71276795 | 205 | /* |
206 | * Read packets from the client unless we have too much | |
207 | * buffered stdin or channel data. | |
208 | */ | |
209 | if (buffer_len(&stdin_buffer) < buffer_high && | |
e78a59f5 | 210 | channel_not_very_much_buffered_data()) |
211 | FD_SET(connection_in, readset); | |
71276795 | 212 | /* |
213 | * If there is not too much data already buffered going to | |
214 | * the client, try to get some more data from the program. | |
215 | */ | |
216 | if (packet_not_very_much_data_to_write()) { | |
217 | if (!fdout_eof) | |
218 | FD_SET(fdout, readset); | |
219 | if (!fderr_eof) | |
220 | FD_SET(fderr, readset); | |
221 | } | |
222 | /* | |
223 | * If we have buffered data, try to write some of that data | |
224 | * to the program. | |
225 | */ | |
226 | if (fdin != -1 && buffer_len(&stdin_buffer) > 0) | |
227 | FD_SET(fdin, writeset); | |
e78a59f5 | 228 | } |
5260325f | 229 | /* Set masks for channel descriptors. */ |
230 | channel_prepare_select(readset, writeset); | |
231 | ||
aa3378df | 232 | /* |
233 | * If we have buffered packet data going to the client, mark that | |
234 | * descriptor. | |
235 | */ | |
5260325f | 236 | if (packet_have_data_to_write()) |
237 | FD_SET(connection_out, writeset); | |
238 | ||
5260325f | 239 | /* Update the maximum descriptor number if appropriate. */ |
240 | if (channel_max_fd() > max_fd) | |
241 | max_fd = channel_max_fd(); | |
242 | ||
aa3378df | 243 | /* |
244 | * If child has terminated and there is enough buffer space to read | |
245 | * from it, then read as much as is available and exit. | |
246 | */ | |
5260325f | 247 | if (child_terminated && packet_not_very_much_data_to_write()) |
248 | if (max_time_milliseconds == 0) | |
249 | max_time_milliseconds = 100; | |
250 | ||
251 | if (max_time_milliseconds == 0) | |
252 | tvp = NULL; | |
253 | else { | |
254 | tv.tv_sec = max_time_milliseconds / 1000; | |
255 | tv.tv_usec = 1000 * (max_time_milliseconds % 1000); | |
256 | tvp = &tv; | |
257 | } | |
e78a59f5 | 258 | if (tvp!=NULL) |
259 | debug("tvp!=NULL kid %d mili %d", child_terminated, max_time_milliseconds); | |
8efc0c15 | 260 | |
5260325f | 261 | /* Wait for something to happen, or the timeout to expire. */ |
262 | ret = select(max_fd + 1, readset, writeset, NULL, tvp); | |
8efc0c15 | 263 | |
5260325f | 264 | if (ret < 0) { |
265 | if (errno != EINTR) | |
266 | error("select: %.100s", strerror(errno)); | |
267 | else | |
268 | goto retry_select; | |
8efc0c15 | 269 | } |
691a8a9f | 270 | |
271 | if (child_terminated) | |
272 | child_has_selected = 1; | |
8efc0c15 | 273 | } |
274 | ||
5260325f | 275 | /* |
276 | * Processes input from the client and the program. Input data is stored | |
277 | * in buffers and processed later. | |
278 | */ | |
6ae2364d | 279 | void |
5260325f | 280 | process_input(fd_set * readset) |
281 | { | |
282 | int len; | |
283 | char buf[16384]; | |
284 | ||
285 | /* Read and buffer any input data from the client. */ | |
286 | if (FD_ISSET(connection_in, readset)) { | |
287 | len = read(connection_in, buf, sizeof(buf)); | |
288 | if (len == 0) { | |
289 | verbose("Connection closed by remote host."); | |
290 | fatal_cleanup(); | |
0e73cc53 | 291 | } else if (len < 0) { |
292 | if (errno != EINTR && errno != EAGAIN) { | |
293 | verbose("Read error from remote host: %.100s", strerror(errno)); | |
294 | fatal_cleanup(); | |
295 | } | |
296 | } else { | |
297 | /* Buffer any received data. */ | |
298 | packet_process_incoming(buf, len); | |
5260325f | 299 | } |
5260325f | 300 | } |
e78a59f5 | 301 | if (compat20) |
302 | return; | |
303 | ||
5260325f | 304 | /* Read and buffer any available stdout data from the program. */ |
305 | if (!fdout_eof && FD_ISSET(fdout, readset)) { | |
306 | len = read(fdout, buf, sizeof(buf)); | |
0e73cc53 | 307 | if (len < 0 && (errno == EINTR || errno == EAGAIN)) { |
308 | /* do nothing */ | |
309 | } else if (len <= 0) { | |
5260325f | 310 | fdout_eof = 1; |
0e73cc53 | 311 | } else { |
5260325f | 312 | buffer_append(&stdout_buffer, buf, len); |
313 | fdout_bytes += len; | |
314 | } | |
315 | } | |
316 | /* Read and buffer any available stderr data from the program. */ | |
317 | if (!fderr_eof && FD_ISSET(fderr, readset)) { | |
318 | len = read(fderr, buf, sizeof(buf)); | |
0e73cc53 | 319 | if (len < 0 && (errno == EINTR || errno == EAGAIN)) { |
320 | /* do nothing */ | |
321 | } else if (len <= 0) { | |
5260325f | 322 | fderr_eof = 1; |
0e73cc53 | 323 | } else { |
5260325f | 324 | buffer_append(&stderr_buffer, buf, len); |
0e73cc53 | 325 | } |
5260325f | 326 | } |
327 | } | |
8efc0c15 | 328 | |
5260325f | 329 | /* |
330 | * Sends data from internal buffers to client program stdin. | |
331 | */ | |
6ae2364d | 332 | void |
5260325f | 333 | process_output(fd_set * writeset) |
8efc0c15 | 334 | { |
5260325f | 335 | int len; |
336 | ||
337 | /* Write buffered data to program stdin. */ | |
e78a59f5 | 338 | if (!compat20 && fdin != -1 && FD_ISSET(fdin, writeset)) { |
5260325f | 339 | len = write(fdin, buffer_ptr(&stdin_buffer), |
a408af76 | 340 | buffer_len(&stdin_buffer)); |
0e73cc53 | 341 | if (len < 0 && (errno == EINTR || errno == EAGAIN)) { |
342 | /* do nothing */ | |
343 | } else if (len <= 0) { | |
8efc0c15 | 344 | #ifdef USE_PIPES |
5260325f | 345 | close(fdin); |
8efc0c15 | 346 | #else |
7368a6c8 | 347 | if (fdin != fdout) |
5260325f | 348 | close(fdin); |
349 | else | |
350 | shutdown(fdin, SHUT_WR); /* We will no longer send. */ | |
8efc0c15 | 351 | #endif |
5260325f | 352 | fdin = -1; |
353 | } else { | |
354 | /* Successful write. Consume the data from the buffer. */ | |
355 | buffer_consume(&stdin_buffer, len); | |
356 | /* Update the count of bytes written to the program. */ | |
357 | stdin_bytes += len; | |
358 | } | |
8efc0c15 | 359 | } |
5260325f | 360 | /* Send any buffered packet data to the client. */ |
361 | if (FD_ISSET(connection_out, writeset)) | |
362 | packet_write_poll(); | |
8efc0c15 | 363 | } |
364 | ||
5260325f | 365 | /* |
366 | * Wait until all buffered output has been sent to the client. | |
367 | * This is used when the program terminates. | |
368 | */ | |
6ae2364d | 369 | void |
5260325f | 370 | drain_output() |
8efc0c15 | 371 | { |
5260325f | 372 | /* Send any buffered stdout data to the client. */ |
373 | if (buffer_len(&stdout_buffer) > 0) { | |
374 | packet_start(SSH_SMSG_STDOUT_DATA); | |
375 | packet_put_string(buffer_ptr(&stdout_buffer), | |
376 | buffer_len(&stdout_buffer)); | |
377 | packet_send(); | |
378 | /* Update the count of sent bytes. */ | |
379 | stdout_bytes += buffer_len(&stdout_buffer); | |
380 | } | |
381 | /* Send any buffered stderr data to the client. */ | |
382 | if (buffer_len(&stderr_buffer) > 0) { | |
383 | packet_start(SSH_SMSG_STDERR_DATA); | |
384 | packet_put_string(buffer_ptr(&stderr_buffer), | |
385 | buffer_len(&stderr_buffer)); | |
386 | packet_send(); | |
387 | /* Update the count of sent bytes. */ | |
388 | stderr_bytes += buffer_len(&stderr_buffer); | |
389 | } | |
390 | /* Wait until all buffered data has been written to the client. */ | |
391 | packet_write_wait(); | |
8efc0c15 | 392 | } |
393 | ||
6ae2364d | 394 | void |
7368a6c8 | 395 | process_buffered_input_packets() |
396 | { | |
188adeb2 | 397 | dispatch_run(DISPATCH_NONBLOCK, NULL, NULL); |
7368a6c8 | 398 | } |
399 | ||
5260325f | 400 | /* |
401 | * Performs the interactive session. This handles data transmission between | |
402 | * the client and the program. Note that the notion of stdin, stdout, and | |
403 | * stderr in this function is sort of reversed: this function writes to | |
404 | * stdin (of the child program), and reads from stdout and stderr (of the | |
405 | * child program). | |
406 | */ | |
6ae2364d | 407 | void |
9da5c3c9 | 408 | server_loop(pid_t pid, int fdin_arg, int fdout_arg, int fderr_arg) |
8efc0c15 | 409 | { |
71276795 | 410 | fd_set readset, writeset; |
9da5c3c9 | 411 | int wait_status; /* Status returned by wait(). */ |
412 | pid_t wait_pid; /* pid returned by wait(). */ | |
5260325f | 413 | int waiting_termination = 0; /* Have displayed waiting close message. */ |
414 | unsigned int max_time_milliseconds; | |
415 | unsigned int previous_stdout_buffer_bytes; | |
416 | unsigned int stdout_buffer_bytes; | |
417 | int type; | |
418 | ||
419 | debug("Entering interactive session."); | |
420 | ||
421 | /* Initialize the SIGCHLD kludge. */ | |
422 | child_pid = pid; | |
423 | child_terminated = 0; | |
691a8a9f | 424 | child_has_selected = 0; |
5260325f | 425 | signal(SIGCHLD, sigchld_handler); |
857040fb | 426 | signal(SIGPIPE, SIG_IGN); |
5260325f | 427 | |
428 | /* Initialize our global variables. */ | |
429 | fdin = fdin_arg; | |
430 | fdout = fdout_arg; | |
431 | fderr = fderr_arg; | |
0e73cc53 | 432 | |
433 | /* nonblocking IO */ | |
434 | set_nonblock(fdin); | |
435 | set_nonblock(fdout); | |
ff873e98 | 436 | /* we don't have stderr for interactive terminal sessions, see below */ |
437 | if (fderr != -1) | |
438 | set_nonblock(fderr); | |
0e73cc53 | 439 | |
5260325f | 440 | connection_in = packet_get_connection_in(); |
441 | connection_out = packet_get_connection_out(); | |
442 | ||
443 | previous_stdout_buffer_bytes = 0; | |
444 | ||
445 | /* Set approximate I/O buffer size. */ | |
446 | if (packet_is_interactive()) | |
447 | buffer_high = 4096; | |
448 | else | |
449 | buffer_high = 64 * 1024; | |
450 | ||
451 | /* Initialize max_fd to the maximum of the known file descriptors. */ | |
452 | max_fd = fdin; | |
453 | if (fdout > max_fd) | |
454 | max_fd = fdout; | |
455 | if (fderr != -1 && fderr > max_fd) | |
456 | max_fd = fderr; | |
457 | if (connection_in > max_fd) | |
458 | max_fd = connection_in; | |
459 | if (connection_out > max_fd) | |
460 | max_fd = connection_out; | |
461 | ||
462 | /* Initialize Initialize buffers. */ | |
463 | buffer_init(&stdin_buffer); | |
464 | buffer_init(&stdout_buffer); | |
465 | buffer_init(&stderr_buffer); | |
466 | ||
aa3378df | 467 | /* |
468 | * If we have no separate fderr (which is the case when we have a pty | |
469 | * - there we cannot make difference between data sent to stdout and | |
470 | * stderr), indicate that we have seen an EOF from stderr. This way | |
471 | * we don\'t need to check the descriptor everywhere. | |
472 | */ | |
5260325f | 473 | if (fderr == -1) |
474 | fderr_eof = 1; | |
475 | ||
7368a6c8 | 476 | server_init_dispatch(); |
477 | ||
5260325f | 478 | /* Main loop of the server for the interactive session mode. */ |
479 | for (;;) { | |
5260325f | 480 | |
481 | /* Process buffered packets from the client. */ | |
482 | process_buffered_input_packets(); | |
483 | ||
aa3378df | 484 | /* |
485 | * If we have received eof, and there is no more pending | |
486 | * input data, cause a real eof by closing fdin. | |
487 | */ | |
5260325f | 488 | if (stdin_eof && fdin != -1 && buffer_len(&stdin_buffer) == 0) { |
8efc0c15 | 489 | #ifdef USE_PIPES |
5260325f | 490 | close(fdin); |
8efc0c15 | 491 | #else |
7368a6c8 | 492 | if (fdin != fdout) |
5260325f | 493 | close(fdin); |
494 | else | |
495 | shutdown(fdin, SHUT_WR); /* We will no longer send. */ | |
8efc0c15 | 496 | #endif |
5260325f | 497 | fdin = -1; |
498 | } | |
aa3378df | 499 | /* Make packets from buffered stderr data to send to the client. */ |
5260325f | 500 | make_packets_from_stderr_data(); |
501 | ||
aa3378df | 502 | /* |
503 | * Make packets from buffered stdout data to send to the | |
504 | * client. If there is very little to send, this arranges to | |
505 | * not send them now, but to wait a short while to see if we | |
506 | * are getting more data. This is necessary, as some systems | |
507 | * wake up readers from a pty after each separate character. | |
508 | */ | |
5260325f | 509 | max_time_milliseconds = 0; |
510 | stdout_buffer_bytes = buffer_len(&stdout_buffer); | |
511 | if (stdout_buffer_bytes != 0 && stdout_buffer_bytes < 256 && | |
512 | stdout_buffer_bytes != previous_stdout_buffer_bytes) { | |
513 | /* try again after a while */ | |
514 | max_time_milliseconds = 10; | |
515 | } else { | |
516 | /* Send it now. */ | |
517 | make_packets_from_stdout_data(); | |
518 | } | |
519 | previous_stdout_buffer_bytes = buffer_len(&stdout_buffer); | |
520 | ||
521 | /* Send channel data to the client. */ | |
522 | if (packet_not_very_much_data_to_write()) | |
523 | channel_output_poll(); | |
524 | ||
aa3378df | 525 | /* |
526 | * Bail out of the loop if the program has closed its output | |
527 | * descriptors, and we have no more data to send to the | |
528 | * client, and there is no pending buffered data. | |
529 | */ | |
691a8a9f | 530 | if (((fdout_eof && fderr_eof) || |
531 | (child_terminated && child_has_selected)) && | |
532 | !packet_have_data_to_write() && | |
533 | (buffer_len(&stdout_buffer) == 0) && | |
534 | (buffer_len(&stderr_buffer) == 0)) { | |
5260325f | 535 | if (!channel_still_open()) |
7368a6c8 | 536 | break; |
5260325f | 537 | if (!waiting_termination) { |
538 | const char *s = "Waiting for forwarded connections to terminate...\r\n"; | |
539 | char *cp; | |
540 | waiting_termination = 1; | |
541 | buffer_append(&stderr_buffer, s, strlen(s)); | |
542 | ||
543 | /* Display list of open channels. */ | |
544 | cp = channel_open_message(); | |
545 | buffer_append(&stderr_buffer, cp, strlen(cp)); | |
546 | xfree(cp); | |
547 | } | |
548 | } | |
549 | /* Sleep in select() until we can do something. */ | |
550 | wait_until_can_do_something(&readset, &writeset, | |
551 | max_time_milliseconds); | |
552 | ||
553 | /* Process any channel events. */ | |
554 | channel_after_select(&readset, &writeset); | |
555 | ||
556 | /* Process input from the client and from program stdout/stderr. */ | |
557 | process_input(&readset); | |
558 | ||
559 | /* Process output to the client and to program stdin. */ | |
560 | process_output(&writeset); | |
8efc0c15 | 561 | } |
562 | ||
5260325f | 563 | /* Cleanup and termination code. */ |
8efc0c15 | 564 | |
5260325f | 565 | /* Wait until all output has been sent to the client. */ |
566 | drain_output(); | |
8efc0c15 | 567 | |
5260325f | 568 | debug("End of interactive session; stdin %ld, stdout (read %ld, sent %ld), stderr %ld bytes.", |
569 | stdin_bytes, fdout_bytes, stdout_bytes, stderr_bytes); | |
8efc0c15 | 570 | |
5260325f | 571 | /* Free and clear the buffers. */ |
572 | buffer_free(&stdin_buffer); | |
573 | buffer_free(&stdout_buffer); | |
574 | buffer_free(&stderr_buffer); | |
8efc0c15 | 575 | |
5260325f | 576 | /* Close the file descriptors. */ |
577 | if (fdout != -1) | |
578 | close(fdout); | |
579 | fdout = -1; | |
580 | fdout_eof = 1; | |
581 | if (fderr != -1) | |
582 | close(fderr); | |
583 | fderr = -1; | |
584 | fderr_eof = 1; | |
585 | if (fdin != -1) | |
586 | close(fdin); | |
587 | fdin = -1; | |
588 | ||
589 | /* Stop listening for channels; this removes unix domain sockets. */ | |
590 | channel_stop_listening(); | |
591 | ||
592 | /* Wait for the child to exit. Get its exit status. */ | |
593 | wait_pid = wait(&wait_status); | |
594 | if (wait_pid < 0) { | |
595 | /* | |
596 | * It is possible that the wait was handled by SIGCHLD | |
597 | * handler. This may result in either: this call | |
598 | * returning with EINTR, or: this call returning ECHILD. | |
599 | */ | |
600 | if (child_terminated) | |
601 | wait_status = child_wait_status; | |
602 | else | |
603 | packet_disconnect("wait: %.100s", strerror(errno)); | |
604 | } else { | |
605 | /* Check if it matches the process we forked. */ | |
606 | if (wait_pid != pid) | |
607 | error("Strange, wait returned pid %d, expected %d", | |
57112b5a | 608 | wait_pid, pid); |
5260325f | 609 | } |
8efc0c15 | 610 | |
5260325f | 611 | /* We no longer want our SIGCHLD handler to be called. */ |
612 | signal(SIGCHLD, SIG_DFL); | |
613 | ||
614 | /* Check if it exited normally. */ | |
615 | if (WIFEXITED(wait_status)) { | |
616 | /* Yes, normal exit. Get exit status and send it to the client. */ | |
617 | debug("Command exited with status %d.", WEXITSTATUS(wait_status)); | |
618 | packet_start(SSH_SMSG_EXITSTATUS); | |
619 | packet_put_int(WEXITSTATUS(wait_status)); | |
620 | packet_send(); | |
621 | packet_write_wait(); | |
622 | ||
aa3378df | 623 | /* |
624 | * Wait for exit confirmation. Note that there might be | |
625 | * other packets coming before it; however, the program has | |
626 | * already died so we just ignore them. The client is | |
627 | * supposed to respond with the confirmation when it receives | |
628 | * the exit status. | |
629 | */ | |
5260325f | 630 | do { |
631 | int plen; | |
632 | type = packet_read(&plen); | |
633 | } | |
634 | while (type != SSH_CMSG_EXIT_CONFIRMATION); | |
635 | ||
636 | debug("Received exit confirmation."); | |
637 | return; | |
638 | } | |
639 | /* Check if the program terminated due to a signal. */ | |
640 | if (WIFSIGNALED(wait_status)) | |
641 | packet_disconnect("Command terminated on signal %d.", | |
642 | WTERMSIG(wait_status)); | |
643 | ||
644 | /* Some weird exit cause. Just exit. */ | |
645 | packet_disconnect("wait returned status %04x.", wait_status); | |
646 | /* NOTREACHED */ | |
647 | } | |
7368a6c8 | 648 | |
6ae2364d | 649 | void |
e78a59f5 | 650 | server_loop2(void) |
651 | { | |
652 | fd_set readset, writeset; | |
653 | int had_channel = 0; | |
654 | int status; | |
655 | pid_t pid; | |
656 | ||
657 | debug("Entering interactive session for SSH2."); | |
658 | ||
659 | signal(SIGCHLD, sigchld_handler2); | |
857040fb | 660 | signal(SIGPIPE, SIG_IGN); |
e78a59f5 | 661 | child_terminated = 0; |
662 | connection_in = packet_get_connection_in(); | |
663 | connection_out = packet_get_connection_out(); | |
664 | max_fd = connection_in; | |
665 | if (connection_out > max_fd) | |
666 | max_fd = connection_out; | |
667 | server_init_dispatch(); | |
668 | ||
669 | for (;;) { | |
670 | process_buffered_input_packets(); | |
671 | if (!had_channel && channel_still_open()) | |
672 | had_channel = 1; | |
673 | if (had_channel && !channel_still_open()) { | |
674 | debug("!channel_still_open."); | |
675 | break; | |
676 | } | |
677 | if (packet_not_very_much_data_to_write()) | |
678 | channel_output_poll(); | |
679 | wait_until_can_do_something(&readset, &writeset, 0); | |
4d670c24 | 680 | if (child_terminated && child_has_selected) { |
681 | /* XXX: race - assumes only one child has terminated */ | |
e78a59f5 | 682 | while ((pid = waitpid(-1, &status, WNOHANG)) > 0) |
683 | session_close_by_pid(pid, status); | |
684 | child_terminated = 0; | |
344f2b94 | 685 | child_has_selected = 0; |
fc1e8bf4 | 686 | signal(SIGCHLD, sigchld_handler2); |
e78a59f5 | 687 | } |
688 | channel_after_select(&readset, &writeset); | |
689 | process_input(&readset); | |
690 | process_output(&writeset); | |
691 | } | |
692 | signal(SIGCHLD, SIG_DFL); | |
693 | while ((pid = waitpid(-1, &status, WNOHANG)) > 0) | |
694 | session_close_by_pid(pid, status); | |
695 | channel_stop_listening(); | |
696 | } | |
697 | ||
7368a6c8 | 698 | void |
188adeb2 | 699 | server_input_stdin_data(int type, int plen, void *ctxt) |
7368a6c8 | 700 | { |
701 | char *data; | |
702 | unsigned int data_len; | |
703 | ||
704 | /* Stdin data from the client. Append it to the buffer. */ | |
705 | /* Ignore any data if the client has closed stdin. */ | |
706 | if (fdin == -1) | |
707 | return; | |
708 | data = packet_get_string(&data_len); | |
709 | packet_integrity_check(plen, (4 + data_len), type); | |
710 | buffer_append(&stdin_buffer, data, data_len); | |
711 | memset(data, 0, data_len); | |
712 | xfree(data); | |
713 | } | |
714 | ||
715 | void | |
188adeb2 | 716 | server_input_eof(int type, int plen, void *ctxt) |
7368a6c8 | 717 | { |
718 | /* | |
719 | * Eof from the client. The stdin descriptor to the | |
720 | * program will be closed when all buffered data has | |
721 | * drained. | |
722 | */ | |
723 | debug("EOF received for stdin."); | |
724 | packet_integrity_check(plen, 0, type); | |
725 | stdin_eof = 1; | |
726 | } | |
727 | ||
728 | void | |
188adeb2 | 729 | server_input_window_size(int type, int plen, void *ctxt) |
7368a6c8 | 730 | { |
731 | int row = packet_get_int(); | |
732 | int col = packet_get_int(); | |
733 | int xpixel = packet_get_int(); | |
734 | int ypixel = packet_get_int(); | |
735 | ||
736 | debug("Window change received."); | |
737 | packet_integrity_check(plen, 4 * 4, type); | |
738 | if (fdin != -1) | |
739 | pty_change_window_size(fdin, row, col, xpixel, ypixel); | |
740 | } | |
741 | ||
e78a59f5 | 742 | int |
743 | input_direct_tcpip(void) | |
744 | { | |
745 | int sock; | |
6ae2364d | 746 | char *target, *originator; |
747 | int target_port, originator_port; | |
e78a59f5 | 748 | |
6ae2364d | 749 | target = packet_get_string(NULL); |
750 | target_port = packet_get_int(); | |
e78a59f5 | 751 | originator = packet_get_string(NULL); |
752 | originator_port = packet_get_int(); | |
6ae2364d | 753 | packet_done(); |
71276795 | 754 | |
755 | debug("open direct-tcpip: from %s port %d to %s port %d", | |
756 | originator, originator_port, target, target_port); | |
38c295d6 | 757 | |
e78a59f5 | 758 | /* XXX check permission */ |
33de75a3 | 759 | if (no_port_forwarding_flag || !options.allow_tcp_forwarding) { |
38c295d6 | 760 | xfree(target); |
761 | xfree(originator); | |
762 | return -1; | |
763 | } | |
6ae2364d | 764 | sock = channel_connect_to(target, target_port); |
765 | xfree(target); | |
e78a59f5 | 766 | xfree(originator); |
767 | if (sock < 0) | |
768 | return -1; | |
769 | return channel_new("direct-tcpip", SSH_CHANNEL_OPEN, | |
bcbf86ec | 770 | sock, sock, -1, CHAN_TCP_WINDOW_DEFAULT, |
a22aff1f | 771 | CHAN_TCP_PACKET_DEFAULT, 0, xstrdup("direct-tcpip"), 1); |
e78a59f5 | 772 | } |
773 | ||
6ae2364d | 774 | void |
188adeb2 | 775 | server_input_channel_open(int type, int plen, void *ctxt) |
e78a59f5 | 776 | { |
777 | Channel *c = NULL; | |
778 | char *ctype; | |
779 | int id; | |
780 | unsigned int len; | |
781 | int rchan; | |
782 | int rmaxpack; | |
783 | int rwindow; | |
784 | ||
785 | ctype = packet_get_string(&len); | |
786 | rchan = packet_get_int(); | |
787 | rwindow = packet_get_int(); | |
788 | rmaxpack = packet_get_int(); | |
789 | ||
188adeb2 | 790 | debug("server_input_channel_open: ctype %s rchan %d win %d max %d", |
e78a59f5 | 791 | ctype, rchan, rwindow, rmaxpack); |
792 | ||
793 | if (strcmp(ctype, "session") == 0) { | |
794 | debug("open session"); | |
6ae2364d | 795 | packet_done(); |
e78a59f5 | 796 | /* |
797 | * A server session has no fd to read or write | |
798 | * until a CHANNEL_REQUEST for a shell is made, | |
799 | * so we set the type to SSH_CHANNEL_LARVAL. | |
800 | * Additionally, a callback for handling all | |
801 | * CHANNEL_REQUEST messages is registered. | |
802 | */ | |
803 | id = channel_new(ctype, SSH_CHANNEL_LARVAL, | |
bcbf86ec | 804 | -1, -1, -1, 0, CHAN_SES_PACKET_DEFAULT, |
a22aff1f | 805 | 0, xstrdup("server-session"), 1); |
e78a59f5 | 806 | if (session_open(id) == 1) { |
807 | channel_register_callback(id, SSH2_MSG_CHANNEL_REQUEST, | |
808 | session_input_channel_req, (void *)0); | |
809 | channel_register_cleanup(id, session_close_by_channel); | |
810 | c = channel_lookup(id); | |
811 | } else { | |
812 | debug("session open failed, free channel %d", id); | |
813 | channel_free(id); | |
814 | } | |
815 | } else if (strcmp(ctype, "direct-tcpip") == 0) { | |
e78a59f5 | 816 | id = input_direct_tcpip(); |
817 | if (id >= 0) | |
818 | c = channel_lookup(id); | |
819 | } | |
820 | if (c != NULL) { | |
821 | debug("confirm %s", ctype); | |
822 | c->remote_id = rchan; | |
823 | c->remote_window = rwindow; | |
824 | c->remote_maxpacket = rmaxpack; | |
825 | ||
826 | packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION); | |
827 | packet_put_int(c->remote_id); | |
828 | packet_put_int(c->self); | |
829 | packet_put_int(c->local_window); | |
830 | packet_put_int(c->local_maxpacket); | |
831 | packet_send(); | |
832 | } else { | |
833 | debug("failure %s", ctype); | |
834 | packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE); | |
835 | packet_put_int(rchan); | |
836 | packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED); | |
837 | packet_put_cstring("bla bla"); | |
838 | packet_put_cstring(""); | |
839 | packet_send(); | |
840 | } | |
841 | xfree(ctype); | |
842 | } | |
843 | ||
6ae2364d | 844 | void |
e78a59f5 | 845 | server_init_dispatch_20() |
846 | { | |
847 | debug("server_init_dispatch_20"); | |
848 | dispatch_init(&dispatch_protocol_error); | |
849 | dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose); | |
850 | dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data); | |
851 | dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof); | |
852 | dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data); | |
853 | dispatch_set(SSH2_MSG_CHANNEL_OPEN, &server_input_channel_open); | |
854 | dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); | |
855 | dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); | |
856 | dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &channel_input_channel_request); | |
857 | dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust); | |
858 | } | |
6ae2364d | 859 | void |
7368a6c8 | 860 | server_init_dispatch_13() |
861 | { | |
862 | debug("server_init_dispatch_13"); | |
863 | dispatch_init(NULL); | |
864 | dispatch_set(SSH_CMSG_EOF, &server_input_eof); | |
865 | dispatch_set(SSH_CMSG_STDIN_DATA, &server_input_stdin_data); | |
866 | dispatch_set(SSH_CMSG_WINDOW_SIZE, &server_input_window_size); | |
867 | dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close); | |
868 | dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation); | |
869 | dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data); | |
870 | dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); | |
871 | dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); | |
872 | dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open); | |
873 | } | |
6ae2364d | 874 | void |
7368a6c8 | 875 | server_init_dispatch_15() |
876 | { | |
877 | server_init_dispatch_13(); | |
878 | debug("server_init_dispatch_15"); | |
879 | dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof); | |
880 | dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_oclose); | |
881 | } | |
6ae2364d | 882 | void |
7368a6c8 | 883 | server_init_dispatch() |
884 | { | |
e78a59f5 | 885 | if (compat20) |
886 | server_init_dispatch_20(); | |
887 | else if (compat13) | |
7368a6c8 | 888 | server_init_dispatch_13(); |
889 | else | |
890 | server_init_dispatch_15(); | |
891 | } |