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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" | |
42f11eb2 | 38 | RCSID("$OpenBSD: serverloop.c,v 1.42 2001/01/21 19:05:55 markus Exp $"); |
a22aff1f | 39 | |
8efc0c15 | 40 | #include "xmalloc.h" |
8efc0c15 | 41 | #include "packet.h" |
42 | #include "buffer.h" | |
42f11eb2 | 43 | #include "log.h" |
8efc0c15 | 44 | #include "servconf.h" |
45 | #include "pty.h" | |
7368a6c8 | 46 | #include "channels.h" |
7368a6c8 | 47 | #include "compat.h" |
42f11eb2 | 48 | #include "ssh1.h" |
e78a59f5 | 49 | #include "ssh2.h" |
59c97189 | 50 | #include "auth.h" |
e78a59f5 | 51 | #include "session.h" |
7368a6c8 | 52 | #include "dispatch.h" |
38c295d6 | 53 | #include "auth-options.h" |
42f11eb2 | 54 | #include "serverloop.h" |
55 | #include "misc.h" | |
8efc0c15 | 56 | |
33de75a3 | 57 | extern ServerOptions options; |
58 | ||
8efc0c15 | 59 | static Buffer stdin_buffer; /* Buffer for stdin data. */ |
60 | static Buffer stdout_buffer; /* Buffer for stdout data. */ | |
61 | static Buffer stderr_buffer; /* Buffer for stderr data. */ | |
62 | static int fdin; /* Descriptor for stdin (for writing) */ | |
63 | static int fdout; /* Descriptor for stdout (for reading); | |
64 | May be same number as fdin. */ | |
65 | static int fderr; /* Descriptor for stderr. May be -1. */ | |
66 | static long stdin_bytes = 0; /* Number of bytes written to stdin. */ | |
67 | static long stdout_bytes = 0; /* Number of stdout bytes sent to client. */ | |
68 | static long stderr_bytes = 0; /* Number of stderr bytes sent to client. */ | |
69 | static long fdout_bytes = 0; /* Number of stdout bytes read from program. */ | |
70 | static int stdin_eof = 0; /* EOF message received from client. */ | |
71 | static int fdout_eof = 0; /* EOF encountered reading from fdout. */ | |
72 | static int fderr_eof = 0; /* EOF encountered readung from fderr. */ | |
73 | static int connection_in; /* Connection to client (input). */ | |
74 | static int connection_out; /* Connection to client (output). */ | |
1e3b8b07 | 75 | static u_int buffer_high;/* "Soft" max buffer size. */ |
8efc0c15 | 76 | static int max_fd; /* Max file descriptor number for select(). */ |
77 | ||
aa3378df | 78 | /* |
79 | * This SIGCHLD kludge is used to detect when the child exits. The server | |
80 | * will exit after that, as soon as forwarded connections have terminated. | |
81 | */ | |
8efc0c15 | 82 | |
9da5c3c9 | 83 | static pid_t child_pid; /* Pid of the child. */ |
8efc0c15 | 84 | static volatile int child_terminated; /* The child has terminated. */ |
85 | static volatile int child_wait_status; /* Status from wait(). */ | |
86 | ||
7368a6c8 | 87 | void server_init_dispatch(void); |
88 | ||
6ae2364d | 89 | void |
5260325f | 90 | sigchld_handler(int sig) |
8efc0c15 | 91 | { |
5260325f | 92 | int save_errno = errno; |
9da5c3c9 | 93 | pid_t wait_pid; |
94 | ||
5260325f | 95 | debug("Received SIGCHLD."); |
96 | wait_pid = wait((int *) &child_wait_status); | |
97 | if (wait_pid != -1) { | |
98 | if (wait_pid != child_pid) | |
99 | error("Strange, got SIGCHLD and wait returned pid %d but child is %d", | |
100 | wait_pid, child_pid); | |
101 | if (WIFEXITED(child_wait_status) || | |
7062c40f | 102 | WIFSIGNALED(child_wait_status)) |
5260325f | 103 | child_terminated = 1; |
104 | } | |
105 | signal(SIGCHLD, sigchld_handler); | |
106 | errno = save_errno; | |
8efc0c15 | 107 | } |
6ae2364d | 108 | void |
e78a59f5 | 109 | sigchld_handler2(int sig) |
110 | { | |
111 | int save_errno = errno; | |
112 | debug("Received SIGCHLD."); | |
113 | child_terminated = 1; | |
7062c40f | 114 | signal(SIGCHLD, sigchld_handler2); |
e78a59f5 | 115 | errno = save_errno; |
116 | } | |
8efc0c15 | 117 | |
5260325f | 118 | /* |
119 | * Make packets from buffered stderr data, and buffer it for sending | |
120 | * to the client. | |
121 | */ | |
6ae2364d | 122 | void |
5260325f | 123 | make_packets_from_stderr_data() |
8efc0c15 | 124 | { |
5260325f | 125 | int len; |
126 | ||
127 | /* Send buffered stderr data to the client. */ | |
128 | while (buffer_len(&stderr_buffer) > 0 && | |
a408af76 | 129 | packet_not_very_much_data_to_write()) { |
5260325f | 130 | len = buffer_len(&stderr_buffer); |
131 | if (packet_is_interactive()) { | |
132 | if (len > 512) | |
133 | len = 512; | |
134 | } else { | |
135 | /* Keep the packets at reasonable size. */ | |
136 | if (len > packet_get_maxsize()) | |
137 | len = packet_get_maxsize(); | |
138 | } | |
139 | packet_start(SSH_SMSG_STDERR_DATA); | |
140 | packet_put_string(buffer_ptr(&stderr_buffer), len); | |
141 | packet_send(); | |
142 | buffer_consume(&stderr_buffer, len); | |
143 | stderr_bytes += len; | |
8efc0c15 | 144 | } |
8efc0c15 | 145 | } |
146 | ||
5260325f | 147 | /* |
148 | * Make packets from buffered stdout data, and buffer it for sending to the | |
149 | * client. | |
150 | */ | |
6ae2364d | 151 | void |
5260325f | 152 | make_packets_from_stdout_data() |
8efc0c15 | 153 | { |
5260325f | 154 | int len; |
155 | ||
156 | /* Send buffered stdout data to the client. */ | |
157 | while (buffer_len(&stdout_buffer) > 0 && | |
a408af76 | 158 | packet_not_very_much_data_to_write()) { |
5260325f | 159 | len = buffer_len(&stdout_buffer); |
160 | if (packet_is_interactive()) { | |
161 | if (len > 512) | |
162 | len = 512; | |
163 | } else { | |
164 | /* Keep the packets at reasonable size. */ | |
165 | if (len > packet_get_maxsize()) | |
166 | len = packet_get_maxsize(); | |
167 | } | |
168 | packet_start(SSH_SMSG_STDOUT_DATA); | |
169 | packet_put_string(buffer_ptr(&stdout_buffer), len); | |
170 | packet_send(); | |
171 | buffer_consume(&stdout_buffer, len); | |
172 | stdout_bytes += len; | |
8efc0c15 | 173 | } |
8efc0c15 | 174 | } |
175 | ||
5260325f | 176 | /* |
177 | * Sleep in select() until we can do something. This will initialize the | |
178 | * select masks. Upon return, the masks will indicate which descriptors | |
179 | * have data or can accept data. Optionally, a maximum time can be specified | |
180 | * for the duration of the wait (0 = infinite). | |
181 | */ | |
6ae2364d | 182 | void |
5260325f | 183 | wait_until_can_do_something(fd_set * readset, fd_set * writeset, |
1e3b8b07 | 184 | u_int max_time_milliseconds) |
8efc0c15 | 185 | { |
5260325f | 186 | struct timeval tv, *tvp; |
187 | int ret; | |
8efc0c15 | 188 | |
5260325f | 189 | /* When select fails we restart from here. */ |
8efc0c15 | 190 | retry_select: |
191 | ||
5260325f | 192 | /* Initialize select() masks. */ |
193 | FD_ZERO(readset); | |
71276795 | 194 | FD_ZERO(writeset); |
5260325f | 195 | |
e78a59f5 | 196 | if (compat20) { |
1d1ffb87 | 197 | /* wrong: bad condition XXX */ |
e78a59f5 | 198 | if (channel_not_very_much_buffered_data()) |
199 | FD_SET(connection_in, readset); | |
200 | } else { | |
71276795 | 201 | /* |
202 | * Read packets from the client unless we have too much | |
203 | * buffered stdin or channel data. | |
204 | */ | |
205 | if (buffer_len(&stdin_buffer) < buffer_high && | |
e78a59f5 | 206 | channel_not_very_much_buffered_data()) |
207 | FD_SET(connection_in, readset); | |
71276795 | 208 | /* |
209 | * If there is not too much data already buffered going to | |
210 | * the client, try to get some more data from the program. | |
211 | */ | |
212 | if (packet_not_very_much_data_to_write()) { | |
213 | if (!fdout_eof) | |
214 | FD_SET(fdout, readset); | |
215 | if (!fderr_eof) | |
216 | FD_SET(fderr, readset); | |
217 | } | |
218 | /* | |
219 | * If we have buffered data, try to write some of that data | |
220 | * to the program. | |
221 | */ | |
222 | if (fdin != -1 && buffer_len(&stdin_buffer) > 0) | |
223 | FD_SET(fdin, writeset); | |
e78a59f5 | 224 | } |
5260325f | 225 | /* Set masks for channel descriptors. */ |
226 | channel_prepare_select(readset, writeset); | |
227 | ||
aa3378df | 228 | /* |
229 | * If we have buffered packet data going to the client, mark that | |
230 | * descriptor. | |
231 | */ | |
5260325f | 232 | if (packet_have_data_to_write()) |
233 | FD_SET(connection_out, writeset); | |
234 | ||
5260325f | 235 | /* Update the maximum descriptor number if appropriate. */ |
236 | if (channel_max_fd() > max_fd) | |
237 | max_fd = channel_max_fd(); | |
238 | ||
aa3378df | 239 | /* |
240 | * If child has terminated and there is enough buffer space to read | |
241 | * from it, then read as much as is available and exit. | |
242 | */ | |
5260325f | 243 | if (child_terminated && packet_not_very_much_data_to_write()) |
244 | if (max_time_milliseconds == 0) | |
245 | max_time_milliseconds = 100; | |
246 | ||
247 | if (max_time_milliseconds == 0) | |
248 | tvp = NULL; | |
249 | else { | |
250 | tv.tv_sec = max_time_milliseconds / 1000; | |
251 | tv.tv_usec = 1000 * (max_time_milliseconds % 1000); | |
252 | tvp = &tv; | |
253 | } | |
e78a59f5 | 254 | if (tvp!=NULL) |
8abcdba4 | 255 | debug2("tvp!=NULL kid %d mili %d", child_terminated, max_time_milliseconds); |
8efc0c15 | 256 | |
5260325f | 257 | /* Wait for something to happen, or the timeout to expire. */ |
258 | ret = select(max_fd + 1, readset, writeset, NULL, tvp); | |
8efc0c15 | 259 | |
5260325f | 260 | if (ret < 0) { |
261 | if (errno != EINTR) | |
262 | error("select: %.100s", strerror(errno)); | |
263 | else | |
264 | goto retry_select; | |
8efc0c15 | 265 | } |
8efc0c15 | 266 | } |
267 | ||
5260325f | 268 | /* |
269 | * Processes input from the client and the program. Input data is stored | |
270 | * in buffers and processed later. | |
271 | */ | |
6ae2364d | 272 | void |
5260325f | 273 | process_input(fd_set * readset) |
274 | { | |
275 | int len; | |
276 | char buf[16384]; | |
277 | ||
278 | /* Read and buffer any input data from the client. */ | |
279 | if (FD_ISSET(connection_in, readset)) { | |
280 | len = read(connection_in, buf, sizeof(buf)); | |
281 | if (len == 0) { | |
282 | verbose("Connection closed by remote host."); | |
283 | fatal_cleanup(); | |
0e73cc53 | 284 | } else if (len < 0) { |
285 | if (errno != EINTR && errno != EAGAIN) { | |
286 | verbose("Read error from remote host: %.100s", strerror(errno)); | |
287 | fatal_cleanup(); | |
288 | } | |
289 | } else { | |
290 | /* Buffer any received data. */ | |
291 | packet_process_incoming(buf, len); | |
5260325f | 292 | } |
5260325f | 293 | } |
e78a59f5 | 294 | if (compat20) |
295 | return; | |
296 | ||
5260325f | 297 | /* Read and buffer any available stdout data from the program. */ |
298 | if (!fdout_eof && FD_ISSET(fdout, readset)) { | |
299 | len = read(fdout, buf, sizeof(buf)); | |
0e73cc53 | 300 | if (len < 0 && (errno == EINTR || errno == EAGAIN)) { |
301 | /* do nothing */ | |
302 | } else if (len <= 0) { | |
5260325f | 303 | fdout_eof = 1; |
0e73cc53 | 304 | } else { |
5260325f | 305 | buffer_append(&stdout_buffer, buf, len); |
306 | fdout_bytes += len; | |
307 | } | |
308 | } | |
309 | /* Read and buffer any available stderr data from the program. */ | |
310 | if (!fderr_eof && FD_ISSET(fderr, readset)) { | |
311 | len = read(fderr, buf, sizeof(buf)); | |
0e73cc53 | 312 | if (len < 0 && (errno == EINTR || errno == EAGAIN)) { |
313 | /* do nothing */ | |
314 | } else if (len <= 0) { | |
5260325f | 315 | fderr_eof = 1; |
0e73cc53 | 316 | } else { |
5260325f | 317 | buffer_append(&stderr_buffer, buf, len); |
0e73cc53 | 318 | } |
5260325f | 319 | } |
320 | } | |
8efc0c15 | 321 | |
5260325f | 322 | /* |
323 | * Sends data from internal buffers to client program stdin. | |
324 | */ | |
6ae2364d | 325 | void |
5260325f | 326 | process_output(fd_set * writeset) |
8efc0c15 | 327 | { |
5260325f | 328 | int len; |
329 | ||
330 | /* Write buffered data to program stdin. */ | |
e78a59f5 | 331 | if (!compat20 && fdin != -1 && FD_ISSET(fdin, writeset)) { |
5260325f | 332 | len = write(fdin, buffer_ptr(&stdin_buffer), |
a408af76 | 333 | buffer_len(&stdin_buffer)); |
0e73cc53 | 334 | if (len < 0 && (errno == EINTR || errno == EAGAIN)) { |
335 | /* do nothing */ | |
336 | } else if (len <= 0) { | |
8efc0c15 | 337 | #ifdef USE_PIPES |
5260325f | 338 | close(fdin); |
8efc0c15 | 339 | #else |
7368a6c8 | 340 | if (fdin != fdout) |
5260325f | 341 | close(fdin); |
342 | else | |
343 | shutdown(fdin, SHUT_WR); /* We will no longer send. */ | |
8efc0c15 | 344 | #endif |
5260325f | 345 | fdin = -1; |
346 | } else { | |
347 | /* Successful write. Consume the data from the buffer. */ | |
348 | buffer_consume(&stdin_buffer, len); | |
349 | /* Update the count of bytes written to the program. */ | |
350 | stdin_bytes += len; | |
351 | } | |
8efc0c15 | 352 | } |
5260325f | 353 | /* Send any buffered packet data to the client. */ |
354 | if (FD_ISSET(connection_out, writeset)) | |
355 | packet_write_poll(); | |
8efc0c15 | 356 | } |
357 | ||
5260325f | 358 | /* |
359 | * Wait until all buffered output has been sent to the client. | |
360 | * This is used when the program terminates. | |
361 | */ | |
6ae2364d | 362 | void |
5260325f | 363 | drain_output() |
8efc0c15 | 364 | { |
5260325f | 365 | /* Send any buffered stdout data to the client. */ |
366 | if (buffer_len(&stdout_buffer) > 0) { | |
367 | packet_start(SSH_SMSG_STDOUT_DATA); | |
368 | packet_put_string(buffer_ptr(&stdout_buffer), | |
369 | buffer_len(&stdout_buffer)); | |
370 | packet_send(); | |
371 | /* Update the count of sent bytes. */ | |
372 | stdout_bytes += buffer_len(&stdout_buffer); | |
373 | } | |
374 | /* Send any buffered stderr data to the client. */ | |
375 | if (buffer_len(&stderr_buffer) > 0) { | |
376 | packet_start(SSH_SMSG_STDERR_DATA); | |
377 | packet_put_string(buffer_ptr(&stderr_buffer), | |
378 | buffer_len(&stderr_buffer)); | |
379 | packet_send(); | |
380 | /* Update the count of sent bytes. */ | |
381 | stderr_bytes += buffer_len(&stderr_buffer); | |
382 | } | |
383 | /* Wait until all buffered data has been written to the client. */ | |
384 | packet_write_wait(); | |
8efc0c15 | 385 | } |
386 | ||
6ae2364d | 387 | void |
7368a6c8 | 388 | process_buffered_input_packets() |
389 | { | |
188adeb2 | 390 | dispatch_run(DISPATCH_NONBLOCK, NULL, NULL); |
7368a6c8 | 391 | } |
392 | ||
5260325f | 393 | /* |
394 | * Performs the interactive session. This handles data transmission between | |
395 | * the client and the program. Note that the notion of stdin, stdout, and | |
396 | * stderr in this function is sort of reversed: this function writes to | |
397 | * stdin (of the child program), and reads from stdout and stderr (of the | |
398 | * child program). | |
399 | */ | |
6ae2364d | 400 | void |
9da5c3c9 | 401 | server_loop(pid_t pid, int fdin_arg, int fdout_arg, int fderr_arg) |
8efc0c15 | 402 | { |
71276795 | 403 | fd_set readset, writeset; |
9da5c3c9 | 404 | int wait_status; /* Status returned by wait(). */ |
405 | pid_t wait_pid; /* pid returned by wait(). */ | |
5260325f | 406 | int waiting_termination = 0; /* Have displayed waiting close message. */ |
1e3b8b07 | 407 | u_int max_time_milliseconds; |
408 | u_int previous_stdout_buffer_bytes; | |
409 | u_int stdout_buffer_bytes; | |
5260325f | 410 | int type; |
411 | ||
412 | debug("Entering interactive session."); | |
413 | ||
414 | /* Initialize the SIGCHLD kludge. */ | |
415 | child_pid = pid; | |
416 | child_terminated = 0; | |
417 | signal(SIGCHLD, sigchld_handler); | |
857040fb | 418 | signal(SIGPIPE, SIG_IGN); |
5260325f | 419 | |
420 | /* Initialize our global variables. */ | |
421 | fdin = fdin_arg; | |
422 | fdout = fdout_arg; | |
423 | fderr = fderr_arg; | |
0e73cc53 | 424 | |
425 | /* nonblocking IO */ | |
426 | set_nonblock(fdin); | |
427 | set_nonblock(fdout); | |
ff873e98 | 428 | /* we don't have stderr for interactive terminal sessions, see below */ |
429 | if (fderr != -1) | |
430 | set_nonblock(fderr); | |
0e73cc53 | 431 | |
5260325f | 432 | connection_in = packet_get_connection_in(); |
433 | connection_out = packet_get_connection_out(); | |
434 | ||
435 | previous_stdout_buffer_bytes = 0; | |
436 | ||
437 | /* Set approximate I/O buffer size. */ | |
438 | if (packet_is_interactive()) | |
439 | buffer_high = 4096; | |
440 | else | |
441 | buffer_high = 64 * 1024; | |
442 | ||
443 | /* Initialize max_fd to the maximum of the known file descriptors. */ | |
444 | max_fd = fdin; | |
445 | if (fdout > max_fd) | |
446 | max_fd = fdout; | |
447 | if (fderr != -1 && fderr > max_fd) | |
448 | max_fd = fderr; | |
449 | if (connection_in > max_fd) | |
450 | max_fd = connection_in; | |
451 | if (connection_out > max_fd) | |
452 | max_fd = connection_out; | |
453 | ||
454 | /* Initialize Initialize buffers. */ | |
455 | buffer_init(&stdin_buffer); | |
456 | buffer_init(&stdout_buffer); | |
457 | buffer_init(&stderr_buffer); | |
458 | ||
aa3378df | 459 | /* |
460 | * If we have no separate fderr (which is the case when we have a pty | |
461 | * - there we cannot make difference between data sent to stdout and | |
462 | * stderr), indicate that we have seen an EOF from stderr. This way | |
463 | * we don\'t need to check the descriptor everywhere. | |
464 | */ | |
5260325f | 465 | if (fderr == -1) |
466 | fderr_eof = 1; | |
467 | ||
7368a6c8 | 468 | server_init_dispatch(); |
469 | ||
5260325f | 470 | /* Main loop of the server for the interactive session mode. */ |
471 | for (;;) { | |
5260325f | 472 | |
473 | /* Process buffered packets from the client. */ | |
474 | process_buffered_input_packets(); | |
475 | ||
aa3378df | 476 | /* |
477 | * If we have received eof, and there is no more pending | |
478 | * input data, cause a real eof by closing fdin. | |
479 | */ | |
5260325f | 480 | if (stdin_eof && fdin != -1 && buffer_len(&stdin_buffer) == 0) { |
8efc0c15 | 481 | #ifdef USE_PIPES |
5260325f | 482 | close(fdin); |
8efc0c15 | 483 | #else |
7368a6c8 | 484 | if (fdin != fdout) |
5260325f | 485 | close(fdin); |
486 | else | |
487 | shutdown(fdin, SHUT_WR); /* We will no longer send. */ | |
8efc0c15 | 488 | #endif |
5260325f | 489 | fdin = -1; |
490 | } | |
aa3378df | 491 | /* Make packets from buffered stderr data to send to the client. */ |
5260325f | 492 | make_packets_from_stderr_data(); |
493 | ||
aa3378df | 494 | /* |
495 | * Make packets from buffered stdout data to send to the | |
496 | * client. If there is very little to send, this arranges to | |
497 | * not send them now, but to wait a short while to see if we | |
498 | * are getting more data. This is necessary, as some systems | |
499 | * wake up readers from a pty after each separate character. | |
500 | */ | |
5260325f | 501 | max_time_milliseconds = 0; |
502 | stdout_buffer_bytes = buffer_len(&stdout_buffer); | |
503 | if (stdout_buffer_bytes != 0 && stdout_buffer_bytes < 256 && | |
504 | stdout_buffer_bytes != previous_stdout_buffer_bytes) { | |
505 | /* try again after a while */ | |
506 | max_time_milliseconds = 10; | |
507 | } else { | |
508 | /* Send it now. */ | |
509 | make_packets_from_stdout_data(); | |
510 | } | |
511 | previous_stdout_buffer_bytes = buffer_len(&stdout_buffer); | |
512 | ||
513 | /* Send channel data to the client. */ | |
514 | if (packet_not_very_much_data_to_write()) | |
515 | channel_output_poll(); | |
516 | ||
aa3378df | 517 | /* |
518 | * Bail out of the loop if the program has closed its output | |
519 | * descriptors, and we have no more data to send to the | |
520 | * client, and there is no pending buffered data. | |
521 | */ | |
7062c40f | 522 | if (fdout_eof && fderr_eof && !packet_have_data_to_write() && |
523 | buffer_len(&stdout_buffer) == 0 && buffer_len(&stderr_buffer) == 0) { | |
5260325f | 524 | if (!channel_still_open()) |
7368a6c8 | 525 | break; |
5260325f | 526 | if (!waiting_termination) { |
527 | const char *s = "Waiting for forwarded connections to terminate...\r\n"; | |
528 | char *cp; | |
529 | waiting_termination = 1; | |
530 | buffer_append(&stderr_buffer, s, strlen(s)); | |
531 | ||
532 | /* Display list of open channels. */ | |
533 | cp = channel_open_message(); | |
534 | buffer_append(&stderr_buffer, cp, strlen(cp)); | |
535 | xfree(cp); | |
536 | } | |
537 | } | |
538 | /* Sleep in select() until we can do something. */ | |
539 | wait_until_can_do_something(&readset, &writeset, | |
540 | max_time_milliseconds); | |
541 | ||
542 | /* Process any channel events. */ | |
543 | channel_after_select(&readset, &writeset); | |
544 | ||
545 | /* Process input from the client and from program stdout/stderr. */ | |
546 | process_input(&readset); | |
547 | ||
548 | /* Process output to the client and to program stdin. */ | |
549 | process_output(&writeset); | |
8efc0c15 | 550 | } |
551 | ||
5260325f | 552 | /* Cleanup and termination code. */ |
8efc0c15 | 553 | |
5260325f | 554 | /* Wait until all output has been sent to the client. */ |
555 | drain_output(); | |
8efc0c15 | 556 | |
5260325f | 557 | debug("End of interactive session; stdin %ld, stdout (read %ld, sent %ld), stderr %ld bytes.", |
558 | stdin_bytes, fdout_bytes, stdout_bytes, stderr_bytes); | |
8efc0c15 | 559 | |
5260325f | 560 | /* Free and clear the buffers. */ |
561 | buffer_free(&stdin_buffer); | |
562 | buffer_free(&stdout_buffer); | |
563 | buffer_free(&stderr_buffer); | |
8efc0c15 | 564 | |
5260325f | 565 | /* Close the file descriptors. */ |
566 | if (fdout != -1) | |
567 | close(fdout); | |
568 | fdout = -1; | |
569 | fdout_eof = 1; | |
570 | if (fderr != -1) | |
571 | close(fderr); | |
572 | fderr = -1; | |
573 | fderr_eof = 1; | |
574 | if (fdin != -1) | |
575 | close(fdin); | |
576 | fdin = -1; | |
577 | ||
578 | /* Stop listening for channels; this removes unix domain sockets. */ | |
579 | channel_stop_listening(); | |
580 | ||
581 | /* Wait for the child to exit. Get its exit status. */ | |
582 | wait_pid = wait(&wait_status); | |
1e3b8b07 | 583 | if (wait_pid == -1) { |
5260325f | 584 | /* |
585 | * It is possible that the wait was handled by SIGCHLD | |
586 | * handler. This may result in either: this call | |
587 | * returning with EINTR, or: this call returning ECHILD. | |
588 | */ | |
589 | if (child_terminated) | |
590 | wait_status = child_wait_status; | |
591 | else | |
592 | packet_disconnect("wait: %.100s", strerror(errno)); | |
593 | } else { | |
594 | /* Check if it matches the process we forked. */ | |
595 | if (wait_pid != pid) | |
596 | error("Strange, wait returned pid %d, expected %d", | |
57112b5a | 597 | wait_pid, pid); |
5260325f | 598 | } |
8efc0c15 | 599 | |
5260325f | 600 | /* We no longer want our SIGCHLD handler to be called. */ |
601 | signal(SIGCHLD, SIG_DFL); | |
602 | ||
603 | /* Check if it exited normally. */ | |
604 | if (WIFEXITED(wait_status)) { | |
605 | /* Yes, normal exit. Get exit status and send it to the client. */ | |
606 | debug("Command exited with status %d.", WEXITSTATUS(wait_status)); | |
607 | packet_start(SSH_SMSG_EXITSTATUS); | |
608 | packet_put_int(WEXITSTATUS(wait_status)); | |
609 | packet_send(); | |
610 | packet_write_wait(); | |
611 | ||
aa3378df | 612 | /* |
613 | * Wait for exit confirmation. Note that there might be | |
614 | * other packets coming before it; however, the program has | |
615 | * already died so we just ignore them. The client is | |
616 | * supposed to respond with the confirmation when it receives | |
617 | * the exit status. | |
618 | */ | |
5260325f | 619 | do { |
620 | int plen; | |
621 | type = packet_read(&plen); | |
622 | } | |
623 | while (type != SSH_CMSG_EXIT_CONFIRMATION); | |
624 | ||
625 | debug("Received exit confirmation."); | |
626 | return; | |
627 | } | |
628 | /* Check if the program terminated due to a signal. */ | |
629 | if (WIFSIGNALED(wait_status)) | |
630 | packet_disconnect("Command terminated on signal %d.", | |
631 | WTERMSIG(wait_status)); | |
632 | ||
633 | /* Some weird exit cause. Just exit. */ | |
634 | packet_disconnect("wait returned status %04x.", wait_status); | |
635 | /* NOTREACHED */ | |
636 | } | |
7368a6c8 | 637 | |
6ae2364d | 638 | void |
e78a59f5 | 639 | server_loop2(void) |
640 | { | |
641 | fd_set readset, writeset; | |
642 | int had_channel = 0; | |
643 | int status; | |
644 | pid_t pid; | |
645 | ||
646 | debug("Entering interactive session for SSH2."); | |
647 | ||
648 | signal(SIGCHLD, sigchld_handler2); | |
857040fb | 649 | signal(SIGPIPE, SIG_IGN); |
e78a59f5 | 650 | child_terminated = 0; |
651 | connection_in = packet_get_connection_in(); | |
652 | connection_out = packet_get_connection_out(); | |
653 | max_fd = connection_in; | |
654 | if (connection_out > max_fd) | |
655 | max_fd = connection_out; | |
656 | server_init_dispatch(); | |
657 | ||
658 | for (;;) { | |
659 | process_buffered_input_packets(); | |
660 | if (!had_channel && channel_still_open()) | |
661 | had_channel = 1; | |
662 | if (had_channel && !channel_still_open()) { | |
663 | debug("!channel_still_open."); | |
664 | break; | |
665 | } | |
666 | if (packet_not_very_much_data_to_write()) | |
667 | channel_output_poll(); | |
668 | wait_until_can_do_something(&readset, &writeset, 0); | |
7062c40f | 669 | if (child_terminated) { |
e78a59f5 | 670 | while ((pid = waitpid(-1, &status, WNOHANG)) > 0) |
671 | session_close_by_pid(pid, status); | |
672 | child_terminated = 0; | |
673 | } | |
674 | channel_after_select(&readset, &writeset); | |
675 | process_input(&readset); | |
676 | process_output(&writeset); | |
677 | } | |
678 | signal(SIGCHLD, SIG_DFL); | |
679 | while ((pid = waitpid(-1, &status, WNOHANG)) > 0) | |
680 | session_close_by_pid(pid, status); | |
681 | channel_stop_listening(); | |
682 | } | |
683 | ||
7368a6c8 | 684 | void |
188adeb2 | 685 | server_input_stdin_data(int type, int plen, void *ctxt) |
7368a6c8 | 686 | { |
687 | char *data; | |
1e3b8b07 | 688 | u_int data_len; |
7368a6c8 | 689 | |
690 | /* Stdin data from the client. Append it to the buffer. */ | |
691 | /* Ignore any data if the client has closed stdin. */ | |
692 | if (fdin == -1) | |
693 | return; | |
694 | data = packet_get_string(&data_len); | |
695 | packet_integrity_check(plen, (4 + data_len), type); | |
696 | buffer_append(&stdin_buffer, data, data_len); | |
697 | memset(data, 0, data_len); | |
698 | xfree(data); | |
699 | } | |
700 | ||
701 | void | |
188adeb2 | 702 | server_input_eof(int type, int plen, void *ctxt) |
7368a6c8 | 703 | { |
704 | /* | |
705 | * Eof from the client. The stdin descriptor to the | |
706 | * program will be closed when all buffered data has | |
707 | * drained. | |
708 | */ | |
709 | debug("EOF received for stdin."); | |
710 | packet_integrity_check(plen, 0, type); | |
711 | stdin_eof = 1; | |
712 | } | |
713 | ||
714 | void | |
188adeb2 | 715 | server_input_window_size(int type, int plen, void *ctxt) |
7368a6c8 | 716 | { |
717 | int row = packet_get_int(); | |
718 | int col = packet_get_int(); | |
719 | int xpixel = packet_get_int(); | |
720 | int ypixel = packet_get_int(); | |
721 | ||
722 | debug("Window change received."); | |
723 | packet_integrity_check(plen, 4 * 4, type); | |
724 | if (fdin != -1) | |
725 | pty_change_window_size(fdin, row, col, xpixel, ypixel); | |
726 | } | |
727 | ||
fa08c86b | 728 | Channel * |
729 | server_request_direct_tcpip(char *ctype) | |
e78a59f5 | 730 | { |
fa08c86b | 731 | int sock, newch; |
6ae2364d | 732 | char *target, *originator; |
733 | int target_port, originator_port; | |
e78a59f5 | 734 | |
6ae2364d | 735 | target = packet_get_string(NULL); |
736 | target_port = packet_get_int(); | |
e78a59f5 | 737 | originator = packet_get_string(NULL); |
738 | originator_port = packet_get_int(); | |
6ae2364d | 739 | packet_done(); |
71276795 | 740 | |
fa08c86b | 741 | debug("server_request_direct_tcpip: originator %s port %d, target %s port %d", |
71276795 | 742 | originator, originator_port, target, target_port); |
38c295d6 | 743 | |
e78a59f5 | 744 | /* XXX check permission */ |
33de75a3 | 745 | if (no_port_forwarding_flag || !options.allow_tcp_forwarding) { |
38c295d6 | 746 | xfree(target); |
747 | xfree(originator); | |
fa08c86b | 748 | return NULL; |
38c295d6 | 749 | } |
6ae2364d | 750 | sock = channel_connect_to(target, target_port); |
751 | xfree(target); | |
e78a59f5 | 752 | xfree(originator); |
753 | if (sock < 0) | |
fa08c86b | 754 | return NULL; |
97fb6912 | 755 | newch = channel_new(ctype, SSH_CHANNEL_CONNECTING, |
bcbf86ec | 756 | sock, sock, -1, CHAN_TCP_WINDOW_DEFAULT, |
a22aff1f | 757 | CHAN_TCP_PACKET_DEFAULT, 0, xstrdup("direct-tcpip"), 1); |
fa08c86b | 758 | return (newch >= 0) ? channel_lookup(newch) : NULL; |
759 | } | |
760 | ||
761 | Channel * | |
762 | server_request_session(char *ctype) | |
763 | { | |
764 | int newch; | |
765 | ||
766 | debug("input_session_request"); | |
767 | packet_done(); | |
768 | /* | |
769 | * A server session has no fd to read or write until a | |
770 | * CHANNEL_REQUEST for a shell is made, so we set the type to | |
771 | * SSH_CHANNEL_LARVAL. Additionally, a callback for handling all | |
772 | * CHANNEL_REQUEST messages is registered. | |
773 | */ | |
774 | newch = channel_new(ctype, SSH_CHANNEL_LARVAL, | |
775 | -1, -1, -1, 0, CHAN_SES_PACKET_DEFAULT, | |
776 | 0, xstrdup("server-session"), 1); | |
777 | if (session_open(newch) == 1) { | |
778 | channel_register_callback(newch, SSH2_MSG_CHANNEL_REQUEST, | |
779 | session_input_channel_req, (void *)0); | |
780 | channel_register_cleanup(newch, session_close_by_channel); | |
781 | return channel_lookup(newch); | |
782 | } else { | |
783 | debug("session open failed, free channel %d", newch); | |
784 | channel_free(newch); | |
785 | } | |
786 | return NULL; | |
e78a59f5 | 787 | } |
788 | ||
6ae2364d | 789 | void |
188adeb2 | 790 | server_input_channel_open(int type, int plen, void *ctxt) |
e78a59f5 | 791 | { |
792 | Channel *c = NULL; | |
793 | char *ctype; | |
1e3b8b07 | 794 | u_int len; |
e78a59f5 | 795 | int rchan; |
796 | int rmaxpack; | |
797 | int rwindow; | |
798 | ||
799 | ctype = packet_get_string(&len); | |
800 | rchan = packet_get_int(); | |
801 | rwindow = packet_get_int(); | |
802 | rmaxpack = packet_get_int(); | |
803 | ||
188adeb2 | 804 | debug("server_input_channel_open: ctype %s rchan %d win %d max %d", |
e78a59f5 | 805 | ctype, rchan, rwindow, rmaxpack); |
806 | ||
807 | if (strcmp(ctype, "session") == 0) { | |
fa08c86b | 808 | c = server_request_session(ctype); |
e78a59f5 | 809 | } else if (strcmp(ctype, "direct-tcpip") == 0) { |
fa08c86b | 810 | c = server_request_direct_tcpip(ctype); |
e78a59f5 | 811 | } |
812 | if (c != NULL) { | |
fa08c86b | 813 | debug("server_input_channel_open: confirm %s", ctype); |
e78a59f5 | 814 | c->remote_id = rchan; |
815 | c->remote_window = rwindow; | |
816 | c->remote_maxpacket = rmaxpack; | |
817 | ||
818 | packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION); | |
819 | packet_put_int(c->remote_id); | |
820 | packet_put_int(c->self); | |
821 | packet_put_int(c->local_window); | |
822 | packet_put_int(c->local_maxpacket); | |
823 | packet_send(); | |
824 | } else { | |
fa08c86b | 825 | debug("server_input_channel_open: failure %s", ctype); |
e78a59f5 | 826 | packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE); |
827 | packet_put_int(rchan); | |
828 | packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED); | |
829 | packet_put_cstring("bla bla"); | |
830 | packet_put_cstring(""); | |
831 | packet_send(); | |
832 | } | |
833 | xfree(ctype); | |
834 | } | |
835 | ||
fa08c86b | 836 | void |
837 | server_input_global_request(int type, int plen, void *ctxt) | |
838 | { | |
839 | char *rtype; | |
840 | int want_reply; | |
841 | int success = 0; | |
842 | ||
843 | rtype = packet_get_string(NULL); | |
844 | want_reply = packet_get_char(); | |
845 | debug("server_input_global_request: rtype %s want_reply %d", rtype, want_reply); | |
846 | ||
847 | if (strcmp(rtype, "tcpip-forward") == 0) { | |
848 | struct passwd *pw; | |
849 | char *listen_address; | |
850 | u_short listen_port; | |
851 | ||
852 | pw = auth_get_user(); | |
853 | if (pw == NULL) | |
854 | fatal("server_input_global_request: no user"); | |
855 | listen_address = packet_get_string(NULL); /* XXX currently ignored */ | |
856 | listen_port = (u_short)packet_get_int(); | |
857 | debug("server_input_global_request: tcpip-forward listen %s port %d", | |
858 | listen_address, listen_port); | |
859 | ||
860 | /* check permissions */ | |
861 | if (!options.allow_tcp_forwarding || | |
862 | no_port_forwarding_flag || | |
863 | (listen_port < IPPORT_RESERVED && pw->pw_uid != 0)) { | |
864 | success = 0; | |
865 | packet_send_debug("Server has disabled port forwarding."); | |
866 | } else { | |
867 | /* Start listening on the port */ | |
868 | channel_request_forwarding( | |
869 | listen_address, listen_port, | |
870 | /*unspec host_to_connect*/ "<unspec host>", | |
871 | /*unspec port_to_connect*/ 0, | |
872 | options.gateway_ports, /*remote*/ 1); | |
873 | success = 1; | |
874 | } | |
875 | xfree(listen_address); | |
876 | } | |
877 | if (want_reply) { | |
878 | packet_start(success ? | |
879 | SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE); | |
880 | packet_send(); | |
881 | packet_write_wait(); | |
882 | } | |
883 | xfree(rtype); | |
884 | } | |
885 | ||
6ae2364d | 886 | void |
e78a59f5 | 887 | server_init_dispatch_20() |
888 | { | |
889 | debug("server_init_dispatch_20"); | |
890 | dispatch_init(&dispatch_protocol_error); | |
891 | dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose); | |
892 | dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data); | |
893 | dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof); | |
894 | dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data); | |
895 | dispatch_set(SSH2_MSG_CHANNEL_OPEN, &server_input_channel_open); | |
896 | dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); | |
897 | dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); | |
898 | dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &channel_input_channel_request); | |
899 | dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust); | |
fa08c86b | 900 | dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &server_input_global_request); |
e78a59f5 | 901 | } |
6ae2364d | 902 | void |
7368a6c8 | 903 | server_init_dispatch_13() |
904 | { | |
905 | debug("server_init_dispatch_13"); | |
906 | dispatch_init(NULL); | |
907 | dispatch_set(SSH_CMSG_EOF, &server_input_eof); | |
908 | dispatch_set(SSH_CMSG_STDIN_DATA, &server_input_stdin_data); | |
909 | dispatch_set(SSH_CMSG_WINDOW_SIZE, &server_input_window_size); | |
910 | dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close); | |
911 | dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation); | |
912 | dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data); | |
913 | dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); | |
914 | dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); | |
915 | dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open); | |
916 | } | |
6ae2364d | 917 | void |
7368a6c8 | 918 | server_init_dispatch_15() |
919 | { | |
920 | server_init_dispatch_13(); | |
921 | debug("server_init_dispatch_15"); | |
922 | dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof); | |
923 | dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_oclose); | |
924 | } | |
6ae2364d | 925 | void |
7368a6c8 | 926 | server_init_dispatch() |
927 | { | |
e78a59f5 | 928 | if (compat20) |
929 | server_init_dispatch_20(); | |
930 | else if (compat13) | |
7368a6c8 | 931 | server_init_dispatch_13(); |
932 | else | |
933 | server_init_dispatch_15(); | |
934 | } |