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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. |
f3c7c613 | 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" | |
6cca9fde | 38 | RCSID("$OpenBSD: serverloop.c,v 1.54 2001/03/04 01:46:30 djm 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" |
1729c161 | 45 | #include "sshpty.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. */ | |
e68225b2 | 73 | static int fdin_is_tty = 0; /* fdin points to a tty. */ |
8efc0c15 | 74 | static int connection_in; /* Connection to client (input). */ |
75 | static int connection_out; /* Connection to client (output). */ | |
1e3b8b07 | 76 | static u_int buffer_high;/* "Soft" max buffer size. */ |
8efc0c15 | 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; | |
1aa00dcb | 114 | mysignal(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 |
5ca51e19 | 123 | make_packets_from_stderr_data(void) |
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 |
5ca51e19 | 152 | make_packets_from_stdout_data(void) |
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()) | |
2b87da3b | 166 | len = packet_get_maxsize(); |
5260325f | 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 |
39929cdb | 183 | wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp, int *maxfdp, |
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 | ||
39929cdb | 192 | /* Allocate and update select() masks for channel descriptors. */ |
193 | channel_prepare_select(readsetp, writesetp, maxfdp); | |
5260325f | 194 | |
e78a59f5 | 195 | if (compat20) { |
1d1ffb87 | 196 | /* wrong: bad condition XXX */ |
e78a59f5 | 197 | if (channel_not_very_much_buffered_data()) |
39929cdb | 198 | FD_SET(connection_in, *readsetp); |
e78a59f5 | 199 | } else { |
71276795 | 200 | /* |
201 | * Read packets from the client unless we have too much | |
202 | * buffered stdin or channel data. | |
203 | */ | |
204 | if (buffer_len(&stdin_buffer) < buffer_high && | |
e78a59f5 | 205 | channel_not_very_much_buffered_data()) |
39929cdb | 206 | FD_SET(connection_in, *readsetp); |
71276795 | 207 | /* |
208 | * If there is not too much data already buffered going to | |
209 | * the client, try to get some more data from the program. | |
210 | */ | |
211 | if (packet_not_very_much_data_to_write()) { | |
212 | if (!fdout_eof) | |
39929cdb | 213 | FD_SET(fdout, *readsetp); |
71276795 | 214 | if (!fderr_eof) |
39929cdb | 215 | FD_SET(fderr, *readsetp); |
71276795 | 216 | } |
217 | /* | |
218 | * If we have buffered data, try to write some of that data | |
219 | * to the program. | |
220 | */ | |
221 | if (fdin != -1 && buffer_len(&stdin_buffer) > 0) | |
39929cdb | 222 | FD_SET(fdin, *writesetp); |
e78a59f5 | 223 | } |
5260325f | 224 | |
aa3378df | 225 | /* |
226 | * If we have buffered packet data going to the client, mark that | |
227 | * descriptor. | |
228 | */ | |
5260325f | 229 | if (packet_have_data_to_write()) |
39929cdb | 230 | FD_SET(connection_out, *writesetp); |
5260325f | 231 | |
aa3378df | 232 | /* |
233 | * If child has terminated and there is enough buffer space to read | |
234 | * from it, then read as much as is available and exit. | |
235 | */ | |
5260325f | 236 | if (child_terminated && packet_not_very_much_data_to_write()) |
237 | if (max_time_milliseconds == 0) | |
238 | max_time_milliseconds = 100; | |
239 | ||
240 | if (max_time_milliseconds == 0) | |
241 | tvp = NULL; | |
242 | else { | |
243 | tv.tv_sec = max_time_milliseconds / 1000; | |
244 | tv.tv_usec = 1000 * (max_time_milliseconds % 1000); | |
245 | tvp = &tv; | |
246 | } | |
e78a59f5 | 247 | if (tvp!=NULL) |
19d57054 | 248 | debug3("tvp!=NULL kid %d mili %d", child_terminated, max_time_milliseconds); |
8efc0c15 | 249 | |
5260325f | 250 | /* Wait for something to happen, or the timeout to expire. */ |
39929cdb | 251 | ret = select((*maxfdp)+1, *readsetp, *writesetp, NULL, tvp); |
8efc0c15 | 252 | |
5260325f | 253 | if (ret < 0) { |
254 | if (errno != EINTR) | |
255 | error("select: %.100s", strerror(errno)); | |
256 | else | |
257 | goto retry_select; | |
8efc0c15 | 258 | } |
8efc0c15 | 259 | } |
260 | ||
5260325f | 261 | /* |
262 | * Processes input from the client and the program. Input data is stored | |
263 | * in buffers and processed later. | |
264 | */ | |
6ae2364d | 265 | void |
5260325f | 266 | process_input(fd_set * readset) |
267 | { | |
268 | int len; | |
269 | char buf[16384]; | |
270 | ||
271 | /* Read and buffer any input data from the client. */ | |
272 | if (FD_ISSET(connection_in, readset)) { | |
273 | len = read(connection_in, buf, sizeof(buf)); | |
274 | if (len == 0) { | |
275 | verbose("Connection closed by remote host."); | |
276 | fatal_cleanup(); | |
0e73cc53 | 277 | } else if (len < 0) { |
278 | if (errno != EINTR && errno != EAGAIN) { | |
279 | verbose("Read error from remote host: %.100s", strerror(errno)); | |
280 | fatal_cleanup(); | |
281 | } | |
282 | } else { | |
283 | /* Buffer any received data. */ | |
284 | packet_process_incoming(buf, len); | |
5260325f | 285 | } |
5260325f | 286 | } |
e78a59f5 | 287 | if (compat20) |
288 | return; | |
289 | ||
5260325f | 290 | /* Read and buffer any available stdout data from the program. */ |
291 | if (!fdout_eof && FD_ISSET(fdout, readset)) { | |
292 | len = read(fdout, buf, sizeof(buf)); | |
0e73cc53 | 293 | if (len < 0 && (errno == EINTR || errno == EAGAIN)) { |
294 | /* do nothing */ | |
295 | } else if (len <= 0) { | |
5260325f | 296 | fdout_eof = 1; |
0e73cc53 | 297 | } else { |
5260325f | 298 | buffer_append(&stdout_buffer, buf, len); |
299 | fdout_bytes += len; | |
300 | } | |
301 | } | |
302 | /* Read and buffer any available stderr data from the program. */ | |
303 | if (!fderr_eof && FD_ISSET(fderr, readset)) { | |
304 | len = read(fderr, buf, sizeof(buf)); | |
0e73cc53 | 305 | if (len < 0 && (errno == EINTR || errno == EAGAIN)) { |
306 | /* do nothing */ | |
307 | } else if (len <= 0) { | |
5260325f | 308 | fderr_eof = 1; |
0e73cc53 | 309 | } else { |
5260325f | 310 | buffer_append(&stderr_buffer, buf, len); |
0e73cc53 | 311 | } |
5260325f | 312 | } |
313 | } | |
8efc0c15 | 314 | |
5260325f | 315 | /* |
316 | * Sends data from internal buffers to client program stdin. | |
317 | */ | |
6ae2364d | 318 | void |
5260325f | 319 | process_output(fd_set * writeset) |
8efc0c15 | 320 | { |
4ef922e3 | 321 | struct termios tio; |
5260325f | 322 | int len; |
323 | ||
324 | /* Write buffered data to program stdin. */ | |
e78a59f5 | 325 | if (!compat20 && fdin != -1 && FD_ISSET(fdin, writeset)) { |
5260325f | 326 | len = write(fdin, buffer_ptr(&stdin_buffer), |
a408af76 | 327 | buffer_len(&stdin_buffer)); |
0e73cc53 | 328 | if (len < 0 && (errno == EINTR || errno == EAGAIN)) { |
329 | /* do nothing */ | |
330 | } else if (len <= 0) { | |
8efc0c15 | 331 | #ifdef USE_PIPES |
5260325f | 332 | close(fdin); |
8efc0c15 | 333 | #else |
7368a6c8 | 334 | if (fdin != fdout) |
5260325f | 335 | close(fdin); |
336 | else | |
337 | shutdown(fdin, SHUT_WR); /* We will no longer send. */ | |
8efc0c15 | 338 | #endif |
5260325f | 339 | fdin = -1; |
340 | } else { | |
4ef922e3 | 341 | /* Successful write. */ |
e68225b2 | 342 | if (fdin_is_tty && tcgetattr(fdin, &tio) == 0 && |
0ae4fe1d | 343 | !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) { |
62da27dd | 344 | /* |
345 | * Simulate echo to reduce the impact of | |
346 | * traffic analysis | |
347 | */ | |
95ce5599 | 348 | packet_send_ignore(len); |
4ef922e3 | 349 | packet_send(); |
350 | } | |
351 | /* Consume the data from the buffer. */ | |
5260325f | 352 | buffer_consume(&stdin_buffer, len); |
353 | /* Update the count of bytes written to the program. */ | |
354 | stdin_bytes += len; | |
355 | } | |
8efc0c15 | 356 | } |
5260325f | 357 | /* Send any buffered packet data to the client. */ |
358 | if (FD_ISSET(connection_out, writeset)) | |
359 | packet_write_poll(); | |
8efc0c15 | 360 | } |
361 | ||
5260325f | 362 | /* |
363 | * Wait until all buffered output has been sent to the client. | |
364 | * This is used when the program terminates. | |
365 | */ | |
6ae2364d | 366 | void |
5ca51e19 | 367 | drain_output(void) |
8efc0c15 | 368 | { |
5260325f | 369 | /* Send any buffered stdout data to the client. */ |
370 | if (buffer_len(&stdout_buffer) > 0) { | |
371 | packet_start(SSH_SMSG_STDOUT_DATA); | |
372 | packet_put_string(buffer_ptr(&stdout_buffer), | |
373 | buffer_len(&stdout_buffer)); | |
374 | packet_send(); | |
375 | /* Update the count of sent bytes. */ | |
376 | stdout_bytes += buffer_len(&stdout_buffer); | |
377 | } | |
378 | /* Send any buffered stderr data to the client. */ | |
379 | if (buffer_len(&stderr_buffer) > 0) { | |
380 | packet_start(SSH_SMSG_STDERR_DATA); | |
381 | packet_put_string(buffer_ptr(&stderr_buffer), | |
382 | buffer_len(&stderr_buffer)); | |
383 | packet_send(); | |
384 | /* Update the count of sent bytes. */ | |
385 | stderr_bytes += buffer_len(&stderr_buffer); | |
386 | } | |
387 | /* Wait until all buffered data has been written to the client. */ | |
388 | packet_write_wait(); | |
8efc0c15 | 389 | } |
390 | ||
6ae2364d | 391 | void |
5ca51e19 | 392 | process_buffered_input_packets(void) |
7368a6c8 | 393 | { |
188adeb2 | 394 | dispatch_run(DISPATCH_NONBLOCK, NULL, NULL); |
7368a6c8 | 395 | } |
396 | ||
5260325f | 397 | /* |
398 | * Performs the interactive session. This handles data transmission between | |
399 | * the client and the program. Note that the notion of stdin, stdout, and | |
400 | * stderr in this function is sort of reversed: this function writes to | |
401 | * stdin (of the child program), and reads from stdout and stderr (of the | |
402 | * child program). | |
403 | */ | |
6ae2364d | 404 | void |
9da5c3c9 | 405 | server_loop(pid_t pid, int fdin_arg, int fdout_arg, int fderr_arg) |
8efc0c15 | 406 | { |
39929cdb | 407 | fd_set *readset = NULL, *writeset = NULL; |
408 | int max_fd; | |
9da5c3c9 | 409 | int wait_status; /* Status returned by wait(). */ |
410 | pid_t wait_pid; /* pid returned by wait(). */ | |
5260325f | 411 | int waiting_termination = 0; /* Have displayed waiting close message. */ |
1e3b8b07 | 412 | u_int max_time_milliseconds; |
413 | u_int previous_stdout_buffer_bytes; | |
414 | u_int stdout_buffer_bytes; | |
5260325f | 415 | int type; |
416 | ||
417 | debug("Entering interactive session."); | |
418 | ||
419 | /* Initialize the SIGCHLD kludge. */ | |
420 | child_pid = pid; | |
421 | child_terminated = 0; | |
422 | signal(SIGCHLD, sigchld_handler); | |
857040fb | 423 | signal(SIGPIPE, SIG_IGN); |
5260325f | 424 | |
425 | /* Initialize our global variables. */ | |
426 | fdin = fdin_arg; | |
427 | fdout = fdout_arg; | |
428 | fderr = fderr_arg; | |
0e73cc53 | 429 | |
430 | /* nonblocking IO */ | |
431 | set_nonblock(fdin); | |
432 | set_nonblock(fdout); | |
ff873e98 | 433 | /* we don't have stderr for interactive terminal sessions, see below */ |
434 | if (fderr != -1) | |
435 | set_nonblock(fderr); | |
0e73cc53 | 436 | |
e68225b2 | 437 | if (!(datafellows & SSH_BUG_IGNOREMSG) && isatty(fdin)) |
438 | fdin_is_tty = 1; | |
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. */ | |
39929cdb | 452 | max_fd = MAX(fdin, fdout); |
453 | if (fderr != -1) | |
454 | max_fd = MAX(max_fd, fderr); | |
455 | max_fd = MAX(max_fd, connection_in); | |
456 | max_fd = MAX(max_fd, connection_out); | |
5260325f | 457 | |
458 | /* Initialize Initialize buffers. */ | |
459 | buffer_init(&stdin_buffer); | |
460 | buffer_init(&stdout_buffer); | |
461 | buffer_init(&stderr_buffer); | |
462 | ||
aa3378df | 463 | /* |
464 | * If we have no separate fderr (which is the case when we have a pty | |
465 | * - there we cannot make difference between data sent to stdout and | |
466 | * stderr), indicate that we have seen an EOF from stderr. This way | |
467 | * we don\'t need to check the descriptor everywhere. | |
468 | */ | |
5260325f | 469 | if (fderr == -1) |
470 | fderr_eof = 1; | |
471 | ||
7368a6c8 | 472 | server_init_dispatch(); |
473 | ||
5260325f | 474 | /* Main loop of the server for the interactive session mode. */ |
475 | for (;;) { | |
5260325f | 476 | |
477 | /* Process buffered packets from the client. */ | |
478 | process_buffered_input_packets(); | |
479 | ||
aa3378df | 480 | /* |
481 | * If we have received eof, and there is no more pending | |
482 | * input data, cause a real eof by closing fdin. | |
483 | */ | |
5260325f | 484 | if (stdin_eof && fdin != -1 && buffer_len(&stdin_buffer) == 0) { |
8efc0c15 | 485 | #ifdef USE_PIPES |
5260325f | 486 | close(fdin); |
8efc0c15 | 487 | #else |
7368a6c8 | 488 | if (fdin != fdout) |
5260325f | 489 | close(fdin); |
490 | else | |
491 | shutdown(fdin, SHUT_WR); /* We will no longer send. */ | |
8efc0c15 | 492 | #endif |
5260325f | 493 | fdin = -1; |
494 | } | |
aa3378df | 495 | /* Make packets from buffered stderr data to send to the client. */ |
5260325f | 496 | make_packets_from_stderr_data(); |
497 | ||
aa3378df | 498 | /* |
499 | * Make packets from buffered stdout data to send to the | |
500 | * client. If there is very little to send, this arranges to | |
501 | * not send them now, but to wait a short while to see if we | |
502 | * are getting more data. This is necessary, as some systems | |
503 | * wake up readers from a pty after each separate character. | |
504 | */ | |
5260325f | 505 | max_time_milliseconds = 0; |
506 | stdout_buffer_bytes = buffer_len(&stdout_buffer); | |
507 | if (stdout_buffer_bytes != 0 && stdout_buffer_bytes < 256 && | |
508 | stdout_buffer_bytes != previous_stdout_buffer_bytes) { | |
509 | /* try again after a while */ | |
510 | max_time_milliseconds = 10; | |
511 | } else { | |
512 | /* Send it now. */ | |
513 | make_packets_from_stdout_data(); | |
514 | } | |
515 | previous_stdout_buffer_bytes = buffer_len(&stdout_buffer); | |
516 | ||
517 | /* Send channel data to the client. */ | |
518 | if (packet_not_very_much_data_to_write()) | |
519 | channel_output_poll(); | |
520 | ||
aa3378df | 521 | /* |
522 | * Bail out of the loop if the program has closed its output | |
523 | * descriptors, and we have no more data to send to the | |
524 | * client, and there is no pending buffered data. | |
525 | */ | |
7062c40f | 526 | if (fdout_eof && fderr_eof && !packet_have_data_to_write() && |
527 | buffer_len(&stdout_buffer) == 0 && buffer_len(&stderr_buffer) == 0) { | |
5260325f | 528 | if (!channel_still_open()) |
7368a6c8 | 529 | break; |
5260325f | 530 | if (!waiting_termination) { |
531 | const char *s = "Waiting for forwarded connections to terminate...\r\n"; | |
532 | char *cp; | |
533 | waiting_termination = 1; | |
534 | buffer_append(&stderr_buffer, s, strlen(s)); | |
535 | ||
536 | /* Display list of open channels. */ | |
537 | cp = channel_open_message(); | |
538 | buffer_append(&stderr_buffer, cp, strlen(cp)); | |
539 | xfree(cp); | |
540 | } | |
541 | } | |
542 | /* Sleep in select() until we can do something. */ | |
39929cdb | 543 | wait_until_can_do_something(&readset, &writeset, &max_fd, |
544 | max_time_milliseconds); | |
5260325f | 545 | |
546 | /* Process any channel events. */ | |
39929cdb | 547 | channel_after_select(readset, writeset); |
5260325f | 548 | |
549 | /* Process input from the client and from program stdout/stderr. */ | |
39929cdb | 550 | process_input(readset); |
5260325f | 551 | |
552 | /* Process output to the client and to program stdin. */ | |
39929cdb | 553 | process_output(writeset); |
8efc0c15 | 554 | } |
39929cdb | 555 | if (readset) |
556 | xfree(readset); | |
557 | if (writeset) | |
558 | xfree(writeset); | |
8efc0c15 | 559 | |
5260325f | 560 | /* Cleanup and termination code. */ |
8efc0c15 | 561 | |
5260325f | 562 | /* Wait until all output has been sent to the client. */ |
563 | drain_output(); | |
8efc0c15 | 564 | |
5260325f | 565 | debug("End of interactive session; stdin %ld, stdout (read %ld, sent %ld), stderr %ld bytes.", |
566 | stdin_bytes, fdout_bytes, stdout_bytes, stderr_bytes); | |
8efc0c15 | 567 | |
5260325f | 568 | /* Free and clear the buffers. */ |
569 | buffer_free(&stdin_buffer); | |
570 | buffer_free(&stdout_buffer); | |
571 | buffer_free(&stderr_buffer); | |
8efc0c15 | 572 | |
5260325f | 573 | /* Close the file descriptors. */ |
574 | if (fdout != -1) | |
575 | close(fdout); | |
576 | fdout = -1; | |
577 | fdout_eof = 1; | |
578 | if (fderr != -1) | |
579 | close(fderr); | |
580 | fderr = -1; | |
581 | fderr_eof = 1; | |
582 | if (fdin != -1) | |
583 | close(fdin); | |
584 | fdin = -1; | |
585 | ||
586 | /* Stop listening for channels; this removes unix domain sockets. */ | |
587 | channel_stop_listening(); | |
588 | ||
589 | /* Wait for the child to exit. Get its exit status. */ | |
590 | wait_pid = wait(&wait_status); | |
1e3b8b07 | 591 | if (wait_pid == -1) { |
5260325f | 592 | /* |
593 | * It is possible that the wait was handled by SIGCHLD | |
594 | * handler. This may result in either: this call | |
595 | * returning with EINTR, or: this call returning ECHILD. | |
596 | */ | |
597 | if (child_terminated) | |
598 | wait_status = child_wait_status; | |
599 | else | |
600 | packet_disconnect("wait: %.100s", strerror(errno)); | |
601 | } else { | |
602 | /* Check if it matches the process we forked. */ | |
603 | if (wait_pid != pid) | |
604 | error("Strange, wait returned pid %d, expected %d", | |
57112b5a | 605 | wait_pid, pid); |
5260325f | 606 | } |
8efc0c15 | 607 | |
5260325f | 608 | /* We no longer want our SIGCHLD handler to be called. */ |
609 | signal(SIGCHLD, SIG_DFL); | |
610 | ||
611 | /* Check if it exited normally. */ | |
612 | if (WIFEXITED(wait_status)) { | |
613 | /* Yes, normal exit. Get exit status and send it to the client. */ | |
614 | debug("Command exited with status %d.", WEXITSTATUS(wait_status)); | |
615 | packet_start(SSH_SMSG_EXITSTATUS); | |
616 | packet_put_int(WEXITSTATUS(wait_status)); | |
617 | packet_send(); | |
618 | packet_write_wait(); | |
619 | ||
aa3378df | 620 | /* |
621 | * Wait for exit confirmation. Note that there might be | |
622 | * other packets coming before it; however, the program has | |
623 | * already died so we just ignore them. The client is | |
624 | * supposed to respond with the confirmation when it receives | |
625 | * the exit status. | |
626 | */ | |
5260325f | 627 | do { |
628 | int plen; | |
629 | type = packet_read(&plen); | |
630 | } | |
631 | while (type != SSH_CMSG_EXIT_CONFIRMATION); | |
632 | ||
633 | debug("Received exit confirmation."); | |
634 | return; | |
635 | } | |
636 | /* Check if the program terminated due to a signal. */ | |
637 | if (WIFSIGNALED(wait_status)) | |
638 | packet_disconnect("Command terminated on signal %d.", | |
639 | WTERMSIG(wait_status)); | |
640 | ||
641 | /* Some weird exit cause. Just exit. */ | |
642 | packet_disconnect("wait returned status %04x.", wait_status); | |
643 | /* NOTREACHED */ | |
644 | } | |
7368a6c8 | 645 | |
6ae2364d | 646 | void |
e78a59f5 | 647 | server_loop2(void) |
648 | { | |
39929cdb | 649 | fd_set *readset = NULL, *writeset = NULL; |
650 | int max_fd; | |
e78a59f5 | 651 | int had_channel = 0; |
652 | int status; | |
653 | pid_t pid; | |
654 | ||
655 | debug("Entering interactive session for SSH2."); | |
656 | ||
1aa00dcb | 657 | mysignal(SIGCHLD, sigchld_handler2); |
857040fb | 658 | signal(SIGPIPE, SIG_IGN); |
e78a59f5 | 659 | child_terminated = 0; |
660 | connection_in = packet_get_connection_in(); | |
661 | connection_out = packet_get_connection_out(); | |
39929cdb | 662 | |
663 | max_fd = MAX(connection_in, connection_out); | |
664 | ||
e78a59f5 | 665 | server_init_dispatch(); |
666 | ||
667 | for (;;) { | |
668 | process_buffered_input_packets(); | |
669 | if (!had_channel && channel_still_open()) | |
670 | had_channel = 1; | |
671 | if (had_channel && !channel_still_open()) { | |
672 | debug("!channel_still_open."); | |
673 | break; | |
674 | } | |
675 | if (packet_not_very_much_data_to_write()) | |
676 | channel_output_poll(); | |
39929cdb | 677 | wait_until_can_do_something(&readset, &writeset, &max_fd, 0); |
7062c40f | 678 | if (child_terminated) { |
e78a59f5 | 679 | while ((pid = waitpid(-1, &status, WNOHANG)) > 0) |
680 | session_close_by_pid(pid, status); | |
681 | child_terminated = 0; | |
682 | } | |
39929cdb | 683 | channel_after_select(readset, writeset); |
684 | process_input(readset); | |
685 | process_output(writeset); | |
e78a59f5 | 686 | } |
39929cdb | 687 | if (readset) |
688 | xfree(readset); | |
689 | if (writeset) | |
690 | xfree(writeset); | |
691 | ||
e78a59f5 | 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; | |
1e3b8b07 | 702 | u_int data_len; |
7368a6c8 | 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 | ||
fa08c86b | 742 | Channel * |
743 | server_request_direct_tcpip(char *ctype) | |
e78a59f5 | 744 | { |
fa08c86b | 745 | int sock, newch; |
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 | |
fa08c86b | 755 | debug("server_request_direct_tcpip: originator %s port %d, target %s port %d", |
71276795 | 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); | |
fa08c86b | 762 | return NULL; |
38c295d6 | 763 | } |
6ae2364d | 764 | sock = channel_connect_to(target, target_port); |
765 | xfree(target); | |
e78a59f5 | 766 | xfree(originator); |
767 | if (sock < 0) | |
fa08c86b | 768 | return NULL; |
97fb6912 | 769 | newch = channel_new(ctype, SSH_CHANNEL_CONNECTING, |
bcbf86ec | 770 | sock, sock, -1, CHAN_TCP_WINDOW_DEFAULT, |
a22aff1f | 771 | CHAN_TCP_PACKET_DEFAULT, 0, xstrdup("direct-tcpip"), 1); |
fa08c86b | 772 | return (newch >= 0) ? channel_lookup(newch) : NULL; |
773 | } | |
774 | ||
775 | Channel * | |
776 | server_request_session(char *ctype) | |
777 | { | |
778 | int newch; | |
779 | ||
780 | debug("input_session_request"); | |
781 | packet_done(); | |
782 | /* | |
783 | * A server session has no fd to read or write until a | |
784 | * CHANNEL_REQUEST for a shell is made, so we set the type to | |
785 | * SSH_CHANNEL_LARVAL. Additionally, a callback for handling all | |
786 | * CHANNEL_REQUEST messages is registered. | |
787 | */ | |
788 | newch = channel_new(ctype, SSH_CHANNEL_LARVAL, | |
789 | -1, -1, -1, 0, CHAN_SES_PACKET_DEFAULT, | |
790 | 0, xstrdup("server-session"), 1); | |
791 | if (session_open(newch) == 1) { | |
792 | channel_register_callback(newch, SSH2_MSG_CHANNEL_REQUEST, | |
793 | session_input_channel_req, (void *)0); | |
794 | channel_register_cleanup(newch, session_close_by_channel); | |
795 | return channel_lookup(newch); | |
796 | } else { | |
797 | debug("session open failed, free channel %d", newch); | |
798 | channel_free(newch); | |
799 | } | |
800 | return NULL; | |
e78a59f5 | 801 | } |
802 | ||
6ae2364d | 803 | void |
188adeb2 | 804 | server_input_channel_open(int type, int plen, void *ctxt) |
e78a59f5 | 805 | { |
806 | Channel *c = NULL; | |
807 | char *ctype; | |
1e3b8b07 | 808 | u_int len; |
e78a59f5 | 809 | int rchan; |
810 | int rmaxpack; | |
811 | int rwindow; | |
812 | ||
813 | ctype = packet_get_string(&len); | |
814 | rchan = packet_get_int(); | |
815 | rwindow = packet_get_int(); | |
816 | rmaxpack = packet_get_int(); | |
817 | ||
188adeb2 | 818 | debug("server_input_channel_open: ctype %s rchan %d win %d max %d", |
e78a59f5 | 819 | ctype, rchan, rwindow, rmaxpack); |
820 | ||
821 | if (strcmp(ctype, "session") == 0) { | |
fa08c86b | 822 | c = server_request_session(ctype); |
e78a59f5 | 823 | } else if (strcmp(ctype, "direct-tcpip") == 0) { |
fa08c86b | 824 | c = server_request_direct_tcpip(ctype); |
e78a59f5 | 825 | } |
826 | if (c != NULL) { | |
fa08c86b | 827 | debug("server_input_channel_open: confirm %s", ctype); |
e78a59f5 | 828 | c->remote_id = rchan; |
829 | c->remote_window = rwindow; | |
830 | c->remote_maxpacket = rmaxpack; | |
831 | ||
832 | packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION); | |
833 | packet_put_int(c->remote_id); | |
834 | packet_put_int(c->self); | |
835 | packet_put_int(c->local_window); | |
836 | packet_put_int(c->local_maxpacket); | |
837 | packet_send(); | |
838 | } else { | |
fa08c86b | 839 | debug("server_input_channel_open: failure %s", ctype); |
e78a59f5 | 840 | packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE); |
841 | packet_put_int(rchan); | |
842 | packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED); | |
843 | packet_put_cstring("bla bla"); | |
844 | packet_put_cstring(""); | |
845 | packet_send(); | |
846 | } | |
847 | xfree(ctype); | |
848 | } | |
849 | ||
2b87da3b | 850 | void |
fa08c86b | 851 | server_input_global_request(int type, int plen, void *ctxt) |
852 | { | |
853 | char *rtype; | |
854 | int want_reply; | |
855 | int success = 0; | |
856 | ||
857 | rtype = packet_get_string(NULL); | |
858 | want_reply = packet_get_char(); | |
859 | debug("server_input_global_request: rtype %s want_reply %d", rtype, want_reply); | |
2b87da3b | 860 | |
fa08c86b | 861 | if (strcmp(rtype, "tcpip-forward") == 0) { |
862 | struct passwd *pw; | |
863 | char *listen_address; | |
864 | u_short listen_port; | |
865 | ||
866 | pw = auth_get_user(); | |
867 | if (pw == NULL) | |
868 | fatal("server_input_global_request: no user"); | |
869 | listen_address = packet_get_string(NULL); /* XXX currently ignored */ | |
870 | listen_port = (u_short)packet_get_int(); | |
871 | debug("server_input_global_request: tcpip-forward listen %s port %d", | |
872 | listen_address, listen_port); | |
873 | ||
874 | /* check permissions */ | |
875 | if (!options.allow_tcp_forwarding || | |
876 | no_port_forwarding_flag || | |
877 | (listen_port < IPPORT_RESERVED && pw->pw_uid != 0)) { | |
878 | success = 0; | |
879 | packet_send_debug("Server has disabled port forwarding."); | |
880 | } else { | |
881 | /* Start listening on the port */ | |
02a024dd | 882 | success = channel_request_forwarding( |
fa08c86b | 883 | listen_address, listen_port, |
884 | /*unspec host_to_connect*/ "<unspec host>", | |
885 | /*unspec port_to_connect*/ 0, | |
886 | options.gateway_ports, /*remote*/ 1); | |
fa08c86b | 887 | } |
888 | xfree(listen_address); | |
889 | } | |
890 | if (want_reply) { | |
891 | packet_start(success ? | |
892 | SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE); | |
893 | packet_send(); | |
894 | packet_write_wait(); | |
895 | } | |
896 | xfree(rtype); | |
897 | } | |
898 | ||
6ae2364d | 899 | void |
5ca51e19 | 900 | server_init_dispatch_20(void) |
e78a59f5 | 901 | { |
902 | debug("server_init_dispatch_20"); | |
903 | dispatch_init(&dispatch_protocol_error); | |
904 | dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose); | |
905 | dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data); | |
906 | dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof); | |
907 | dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data); | |
908 | dispatch_set(SSH2_MSG_CHANNEL_OPEN, &server_input_channel_open); | |
909 | dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); | |
910 | dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); | |
911 | dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &channel_input_channel_request); | |
912 | dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust); | |
fa08c86b | 913 | dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &server_input_global_request); |
e78a59f5 | 914 | } |
6ae2364d | 915 | void |
5ca51e19 | 916 | server_init_dispatch_13(void) |
7368a6c8 | 917 | { |
918 | debug("server_init_dispatch_13"); | |
919 | dispatch_init(NULL); | |
920 | dispatch_set(SSH_CMSG_EOF, &server_input_eof); | |
921 | dispatch_set(SSH_CMSG_STDIN_DATA, &server_input_stdin_data); | |
922 | dispatch_set(SSH_CMSG_WINDOW_SIZE, &server_input_window_size); | |
923 | dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close); | |
924 | dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation); | |
925 | dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data); | |
926 | dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); | |
927 | dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); | |
928 | dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open); | |
929 | } | |
6ae2364d | 930 | void |
5ca51e19 | 931 | server_init_dispatch_15(void) |
7368a6c8 | 932 | { |
933 | server_init_dispatch_13(); | |
934 | debug("server_init_dispatch_15"); | |
935 | dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof); | |
936 | dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_oclose); | |
937 | } | |
6ae2364d | 938 | void |
5ca51e19 | 939 | server_init_dispatch(void) |
7368a6c8 | 940 | { |
e78a59f5 | 941 | if (compat20) |
942 | server_init_dispatch_20(); | |
943 | else if (compat13) | |
7368a6c8 | 944 | server_init_dispatch_13(); |
945 | else | |
946 | server_init_dispatch_15(); | |
947 | } |