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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" | |
396c147e | 38 | RCSID("$OpenBSD: serverloop.c,v 1.70 2001/06/23 15:12:19 itojun 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" |
a5efa1bb | 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" | |
7a37c112 | 56 | #include "kex.h" |
8efc0c15 | 57 | |
33de75a3 | 58 | extern ServerOptions options; |
59 | ||
7a37c112 | 60 | /* XXX */ |
61 | extern Kex *xxx_kex; | |
62 | ||
8efc0c15 | 63 | static Buffer stdin_buffer; /* Buffer for stdin data. */ |
64 | static Buffer stdout_buffer; /* Buffer for stdout data. */ | |
65 | static Buffer stderr_buffer; /* Buffer for stderr data. */ | |
66 | static int fdin; /* Descriptor for stdin (for writing) */ | |
67 | static int fdout; /* Descriptor for stdout (for reading); | |
68 | May be same number as fdin. */ | |
69 | static int fderr; /* Descriptor for stderr. May be -1. */ | |
70 | static long stdin_bytes = 0; /* Number of bytes written to stdin. */ | |
71 | static long stdout_bytes = 0; /* Number of stdout bytes sent to client. */ | |
72 | static long stderr_bytes = 0; /* Number of stderr bytes sent to client. */ | |
73 | static long fdout_bytes = 0; /* Number of stdout bytes read from program. */ | |
74 | static int stdin_eof = 0; /* EOF message received from client. */ | |
75 | static int fdout_eof = 0; /* EOF encountered reading from fdout. */ | |
76 | static int fderr_eof = 0; /* EOF encountered readung from fderr. */ | |
e68225b2 | 77 | static int fdin_is_tty = 0; /* fdin points to a tty. */ |
8efc0c15 | 78 | static int connection_in; /* Connection to client (input). */ |
79 | static int connection_out; /* Connection to client (output). */ | |
cc94bd38 | 80 | static int connection_closed = 0; /* Connection to client closed. */ |
81 | static u_int buffer_high; /* "Soft" max buffer size. */ | |
8efc0c15 | 82 | |
aa3378df | 83 | /* |
84 | * This SIGCHLD kludge is used to detect when the child exits. The server | |
85 | * will exit after that, as soon as forwarded connections have terminated. | |
86 | */ | |
396c147e | 87 | |
8efc0c15 | 88 | static volatile int child_terminated; /* The child has terminated. */ |
8efc0c15 | 89 | |
396c147e | 90 | /* prototypes */ |
91 | static void server_init_dispatch(void); | |
7368a6c8 | 92 | |
3ffc6336 | 93 | int client_alive_timeouts = 0; |
94 | ||
396c147e | 95 | static void |
5260325f | 96 | sigchld_handler(int sig) |
e78a59f5 | 97 | { |
98 | int save_errno = errno; | |
99 | debug("Received SIGCHLD."); | |
100 | child_terminated = 1; | |
c9130033 | 101 | mysignal(SIGCHLD, sigchld_handler); |
e78a59f5 | 102 | errno = save_errno; |
103 | } | |
8efc0c15 | 104 | |
5260325f | 105 | /* |
106 | * Make packets from buffered stderr data, and buffer it for sending | |
107 | * to the client. | |
108 | */ | |
396c147e | 109 | static void |
5ca51e19 | 110 | make_packets_from_stderr_data(void) |
8efc0c15 | 111 | { |
5260325f | 112 | int len; |
113 | ||
114 | /* Send buffered stderr data to the client. */ | |
115 | while (buffer_len(&stderr_buffer) > 0 && | |
a408af76 | 116 | packet_not_very_much_data_to_write()) { |
5260325f | 117 | len = buffer_len(&stderr_buffer); |
118 | if (packet_is_interactive()) { | |
119 | if (len > 512) | |
120 | len = 512; | |
121 | } else { | |
122 | /* Keep the packets at reasonable size. */ | |
123 | if (len > packet_get_maxsize()) | |
124 | len = packet_get_maxsize(); | |
125 | } | |
126 | packet_start(SSH_SMSG_STDERR_DATA); | |
127 | packet_put_string(buffer_ptr(&stderr_buffer), len); | |
128 | packet_send(); | |
129 | buffer_consume(&stderr_buffer, len); | |
130 | stderr_bytes += len; | |
8efc0c15 | 131 | } |
8efc0c15 | 132 | } |
133 | ||
5260325f | 134 | /* |
135 | * Make packets from buffered stdout data, and buffer it for sending to the | |
136 | * client. | |
137 | */ | |
396c147e | 138 | static void |
5ca51e19 | 139 | make_packets_from_stdout_data(void) |
8efc0c15 | 140 | { |
5260325f | 141 | int len; |
142 | ||
143 | /* Send buffered stdout data to the client. */ | |
144 | while (buffer_len(&stdout_buffer) > 0 && | |
a408af76 | 145 | packet_not_very_much_data_to_write()) { |
5260325f | 146 | len = buffer_len(&stdout_buffer); |
147 | if (packet_is_interactive()) { | |
148 | if (len > 512) | |
149 | len = 512; | |
150 | } else { | |
151 | /* Keep the packets at reasonable size. */ | |
152 | if (len > packet_get_maxsize()) | |
2b87da3b | 153 | len = packet_get_maxsize(); |
5260325f | 154 | } |
155 | packet_start(SSH_SMSG_STDOUT_DATA); | |
156 | packet_put_string(buffer_ptr(&stdout_buffer), len); | |
157 | packet_send(); | |
158 | buffer_consume(&stdout_buffer, len); | |
159 | stdout_bytes += len; | |
8efc0c15 | 160 | } |
8efc0c15 | 161 | } |
162 | ||
5260325f | 163 | /* |
164 | * Sleep in select() until we can do something. This will initialize the | |
165 | * select masks. Upon return, the masks will indicate which descriptors | |
166 | * have data or can accept data. Optionally, a maximum time can be specified | |
167 | * for the duration of the wait (0 = infinite). | |
168 | */ | |
396c147e | 169 | static void |
39929cdb | 170 | wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp, int *maxfdp, |
171 | u_int max_time_milliseconds) | |
8efc0c15 | 172 | { |
5260325f | 173 | struct timeval tv, *tvp; |
174 | int ret; | |
3ffc6336 | 175 | int client_alive_scheduled = 0; |
176 | ||
177 | /* | |
178 | * if using client_alive, set the max timeout accordingly, | |
179 | * and indicate that this particular timeout was for client | |
180 | * alive by setting the client_alive_scheduled flag. | |
181 | * | |
182 | * this could be randomized somewhat to make traffic | |
183 | * analysis more difficult, but we're not doing it yet. | |
184 | */ | |
185 | if (max_time_milliseconds == 0 && options.client_alive_interval) { | |
39aefe7b | 186 | client_alive_scheduled = 1; |
3ffc6336 | 187 | max_time_milliseconds = options.client_alive_interval * 1000; |
188 | } else | |
39aefe7b | 189 | client_alive_scheduled = 0; |
8efc0c15 | 190 | |
5260325f | 191 | /* When select fails we restart from here. */ |
8efc0c15 | 192 | retry_select: |
193 | ||
39929cdb | 194 | /* Allocate and update select() masks for channel descriptors. */ |
c422989b | 195 | channel_prepare_select(readsetp, writesetp, maxfdp, 0); |
5260325f | 196 | |
e78a59f5 | 197 | if (compat20) { |
1d1ffb87 | 198 | /* wrong: bad condition XXX */ |
e78a59f5 | 199 | if (channel_not_very_much_buffered_data()) |
39929cdb | 200 | FD_SET(connection_in, *readsetp); |
e78a59f5 | 201 | } else { |
71276795 | 202 | /* |
203 | * Read packets from the client unless we have too much | |
204 | * buffered stdin or channel data. | |
205 | */ | |
206 | if (buffer_len(&stdin_buffer) < buffer_high && | |
e78a59f5 | 207 | channel_not_very_much_buffered_data()) |
39929cdb | 208 | FD_SET(connection_in, *readsetp); |
71276795 | 209 | /* |
210 | * If there is not too much data already buffered going to | |
211 | * the client, try to get some more data from the program. | |
212 | */ | |
213 | if (packet_not_very_much_data_to_write()) { | |
214 | if (!fdout_eof) | |
39929cdb | 215 | FD_SET(fdout, *readsetp); |
71276795 | 216 | if (!fderr_eof) |
39929cdb | 217 | FD_SET(fderr, *readsetp); |
71276795 | 218 | } |
219 | /* | |
220 | * If we have buffered data, try to write some of that data | |
221 | * to the program. | |
222 | */ | |
223 | if (fdin != -1 && buffer_len(&stdin_buffer) > 0) | |
39929cdb | 224 | FD_SET(fdin, *writesetp); |
e78a59f5 | 225 | } |
5260325f | 226 | |
aa3378df | 227 | /* |
228 | * If we have buffered packet data going to the client, mark that | |
229 | * descriptor. | |
230 | */ | |
5260325f | 231 | if (packet_have_data_to_write()) |
39929cdb | 232 | FD_SET(connection_out, *writesetp); |
5260325f | 233 | |
aa3378df | 234 | /* |
235 | * If child has terminated and there is enough buffer space to read | |
236 | * from it, then read as much as is available and exit. | |
237 | */ | |
5260325f | 238 | if (child_terminated && packet_not_very_much_data_to_write()) |
3ffc6336 | 239 | if (max_time_milliseconds == 0 || client_alive_scheduled) |
5260325f | 240 | max_time_milliseconds = 100; |
241 | ||
242 | if (max_time_milliseconds == 0) | |
243 | tvp = NULL; | |
244 | else { | |
245 | tv.tv_sec = max_time_milliseconds / 1000; | |
246 | tv.tv_usec = 1000 * (max_time_milliseconds % 1000); | |
247 | tvp = &tv; | |
248 | } | |
e78a59f5 | 249 | if (tvp!=NULL) |
19d57054 | 250 | debug3("tvp!=NULL kid %d mili %d", child_terminated, max_time_milliseconds); |
8efc0c15 | 251 | |
5260325f | 252 | /* Wait for something to happen, or the timeout to expire. */ |
39929cdb | 253 | ret = select((*maxfdp)+1, *readsetp, *writesetp, NULL, tvp); |
8efc0c15 | 254 | |
3ffc6336 | 255 | if (ret == -1) { |
5260325f | 256 | if (errno != EINTR) |
257 | error("select: %.100s", strerror(errno)); | |
258 | else | |
259 | goto retry_select; | |
8efc0c15 | 260 | } |
3ffc6336 | 261 | if (ret == 0 && client_alive_scheduled) { |
262 | /* timeout, check to see how many we have had */ | |
263 | client_alive_timeouts++; | |
264 | ||
265 | if (client_alive_timeouts > options.client_alive_count_max ) { | |
266 | packet_disconnect( | |
267 | "Timeout, your session not responding."); | |
268 | } else { | |
269 | /* | |
270 | * send a bogus channel request with "wantreply" | |
271 | * we should get back a failure | |
272 | */ | |
273 | int id; | |
274 | ||
275 | id = channel_find_open(); | |
276 | if (id != -1) { | |
277 | channel_request_start(id, | |
278 | "keepalive@openssh.com", 1); | |
279 | packet_send(); | |
280 | } else | |
281 | packet_disconnect( | |
282 | "No open channels after timeout!"); | |
283 | } | |
284 | } | |
8efc0c15 | 285 | } |
286 | ||
5260325f | 287 | /* |
288 | * Processes input from the client and the program. Input data is stored | |
289 | * in buffers and processed later. | |
290 | */ | |
396c147e | 291 | static void |
5260325f | 292 | process_input(fd_set * readset) |
293 | { | |
294 | int len; | |
295 | char buf[16384]; | |
296 | ||
297 | /* Read and buffer any input data from the client. */ | |
298 | if (FD_ISSET(connection_in, readset)) { | |
299 | len = read(connection_in, buf, sizeof(buf)); | |
300 | if (len == 0) { | |
301 | verbose("Connection closed by remote host."); | |
cc94bd38 | 302 | connection_closed = 1; |
303 | if (compat20) | |
304 | return; | |
5260325f | 305 | fatal_cleanup(); |
0e73cc53 | 306 | } else if (len < 0) { |
307 | if (errno != EINTR && errno != EAGAIN) { | |
308 | verbose("Read error from remote host: %.100s", strerror(errno)); | |
309 | fatal_cleanup(); | |
310 | } | |
311 | } else { | |
312 | /* Buffer any received data. */ | |
313 | packet_process_incoming(buf, len); | |
5260325f | 314 | } |
5260325f | 315 | } |
e78a59f5 | 316 | if (compat20) |
317 | return; | |
318 | ||
5260325f | 319 | /* Read and buffer any available stdout data from the program. */ |
320 | if (!fdout_eof && FD_ISSET(fdout, readset)) { | |
321 | len = read(fdout, buf, sizeof(buf)); | |
0e73cc53 | 322 | if (len < 0 && (errno == EINTR || errno == EAGAIN)) { |
323 | /* do nothing */ | |
324 | } else if (len <= 0) { | |
5260325f | 325 | fdout_eof = 1; |
0e73cc53 | 326 | } else { |
5260325f | 327 | buffer_append(&stdout_buffer, buf, len); |
328 | fdout_bytes += len; | |
329 | } | |
330 | } | |
331 | /* Read and buffer any available stderr data from the program. */ | |
332 | if (!fderr_eof && FD_ISSET(fderr, readset)) { | |
333 | len = read(fderr, buf, sizeof(buf)); | |
0e73cc53 | 334 | if (len < 0 && (errno == EINTR || errno == EAGAIN)) { |
335 | /* do nothing */ | |
336 | } else if (len <= 0) { | |
5260325f | 337 | fderr_eof = 1; |
0e73cc53 | 338 | } else { |
5260325f | 339 | buffer_append(&stderr_buffer, buf, len); |
0e73cc53 | 340 | } |
5260325f | 341 | } |
342 | } | |
8efc0c15 | 343 | |
5260325f | 344 | /* |
345 | * Sends data from internal buffers to client program stdin. | |
346 | */ | |
396c147e | 347 | static void |
5260325f | 348 | process_output(fd_set * writeset) |
8efc0c15 | 349 | { |
4ef922e3 | 350 | struct termios tio; |
5260325f | 351 | int len; |
352 | ||
353 | /* Write buffered data to program stdin. */ | |
e78a59f5 | 354 | if (!compat20 && fdin != -1 && FD_ISSET(fdin, writeset)) { |
5260325f | 355 | len = write(fdin, buffer_ptr(&stdin_buffer), |
a408af76 | 356 | buffer_len(&stdin_buffer)); |
0e73cc53 | 357 | if (len < 0 && (errno == EINTR || errno == EAGAIN)) { |
358 | /* do nothing */ | |
359 | } else if (len <= 0) { | |
8efc0c15 | 360 | #ifdef USE_PIPES |
5260325f | 361 | close(fdin); |
8efc0c15 | 362 | #else |
7368a6c8 | 363 | if (fdin != fdout) |
5260325f | 364 | close(fdin); |
365 | else | |
366 | shutdown(fdin, SHUT_WR); /* We will no longer send. */ | |
8efc0c15 | 367 | #endif |
5260325f | 368 | fdin = -1; |
369 | } else { | |
4ef922e3 | 370 | /* Successful write. */ |
e68225b2 | 371 | if (fdin_is_tty && tcgetattr(fdin, &tio) == 0 && |
0ae4fe1d | 372 | !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) { |
62da27dd | 373 | /* |
374 | * Simulate echo to reduce the impact of | |
375 | * traffic analysis | |
376 | */ | |
95ce5599 | 377 | packet_send_ignore(len); |
4ef922e3 | 378 | packet_send(); |
379 | } | |
380 | /* Consume the data from the buffer. */ | |
5260325f | 381 | buffer_consume(&stdin_buffer, len); |
382 | /* Update the count of bytes written to the program. */ | |
383 | stdin_bytes += len; | |
384 | } | |
8efc0c15 | 385 | } |
5260325f | 386 | /* Send any buffered packet data to the client. */ |
387 | if (FD_ISSET(connection_out, writeset)) | |
388 | packet_write_poll(); | |
8efc0c15 | 389 | } |
390 | ||
5260325f | 391 | /* |
392 | * Wait until all buffered output has been sent to the client. | |
393 | * This is used when the program terminates. | |
394 | */ | |
396c147e | 395 | static void |
5ca51e19 | 396 | drain_output(void) |
8efc0c15 | 397 | { |
5260325f | 398 | /* Send any buffered stdout data to the client. */ |
399 | if (buffer_len(&stdout_buffer) > 0) { | |
400 | packet_start(SSH_SMSG_STDOUT_DATA); | |
401 | packet_put_string(buffer_ptr(&stdout_buffer), | |
402 | buffer_len(&stdout_buffer)); | |
403 | packet_send(); | |
404 | /* Update the count of sent bytes. */ | |
405 | stdout_bytes += buffer_len(&stdout_buffer); | |
406 | } | |
407 | /* Send any buffered stderr data to the client. */ | |
408 | if (buffer_len(&stderr_buffer) > 0) { | |
409 | packet_start(SSH_SMSG_STDERR_DATA); | |
410 | packet_put_string(buffer_ptr(&stderr_buffer), | |
411 | buffer_len(&stderr_buffer)); | |
412 | packet_send(); | |
413 | /* Update the count of sent bytes. */ | |
414 | stderr_bytes += buffer_len(&stderr_buffer); | |
415 | } | |
416 | /* Wait until all buffered data has been written to the client. */ | |
417 | packet_write_wait(); | |
8efc0c15 | 418 | } |
419 | ||
396c147e | 420 | static void |
5ca51e19 | 421 | process_buffered_input_packets(void) |
7368a6c8 | 422 | { |
7a37c112 | 423 | dispatch_run(DISPATCH_NONBLOCK, NULL, compat20 ? xxx_kex : NULL); |
7368a6c8 | 424 | } |
425 | ||
5260325f | 426 | /* |
427 | * Performs the interactive session. This handles data transmission between | |
428 | * the client and the program. Note that the notion of stdin, stdout, and | |
429 | * stderr in this function is sort of reversed: this function writes to | |
430 | * stdin (of the child program), and reads from stdout and stderr (of the | |
431 | * child program). | |
432 | */ | |
6ae2364d | 433 | void |
9da5c3c9 | 434 | server_loop(pid_t pid, int fdin_arg, int fdout_arg, int fderr_arg) |
8efc0c15 | 435 | { |
39929cdb | 436 | fd_set *readset = NULL, *writeset = NULL; |
437 | int max_fd; | |
9da5c3c9 | 438 | int wait_status; /* Status returned by wait(). */ |
439 | pid_t wait_pid; /* pid returned by wait(). */ | |
5260325f | 440 | int waiting_termination = 0; /* Have displayed waiting close message. */ |
1e3b8b07 | 441 | u_int max_time_milliseconds; |
442 | u_int previous_stdout_buffer_bytes; | |
443 | u_int stdout_buffer_bytes; | |
5260325f | 444 | int type; |
445 | ||
446 | debug("Entering interactive session."); | |
447 | ||
448 | /* Initialize the SIGCHLD kludge. */ | |
5260325f | 449 | child_terminated = 0; |
450 | signal(SIGCHLD, sigchld_handler); | |
451 | ||
452 | /* Initialize our global variables. */ | |
453 | fdin = fdin_arg; | |
454 | fdout = fdout_arg; | |
455 | fderr = fderr_arg; | |
0e73cc53 | 456 | |
457 | /* nonblocking IO */ | |
458 | set_nonblock(fdin); | |
459 | set_nonblock(fdout); | |
ff873e98 | 460 | /* we don't have stderr for interactive terminal sessions, see below */ |
461 | if (fderr != -1) | |
462 | set_nonblock(fderr); | |
0e73cc53 | 463 | |
e68225b2 | 464 | if (!(datafellows & SSH_BUG_IGNOREMSG) && isatty(fdin)) |
465 | fdin_is_tty = 1; | |
466 | ||
5260325f | 467 | connection_in = packet_get_connection_in(); |
468 | connection_out = packet_get_connection_out(); | |
469 | ||
470 | previous_stdout_buffer_bytes = 0; | |
471 | ||
472 | /* Set approximate I/O buffer size. */ | |
473 | if (packet_is_interactive()) | |
474 | buffer_high = 4096; | |
475 | else | |
476 | buffer_high = 64 * 1024; | |
477 | ||
478 | /* Initialize max_fd to the maximum of the known file descriptors. */ | |
39929cdb | 479 | max_fd = MAX(fdin, fdout); |
480 | if (fderr != -1) | |
481 | max_fd = MAX(max_fd, fderr); | |
482 | max_fd = MAX(max_fd, connection_in); | |
483 | max_fd = MAX(max_fd, connection_out); | |
5260325f | 484 | |
485 | /* Initialize Initialize buffers. */ | |
486 | buffer_init(&stdin_buffer); | |
487 | buffer_init(&stdout_buffer); | |
488 | buffer_init(&stderr_buffer); | |
489 | ||
aa3378df | 490 | /* |
491 | * If we have no separate fderr (which is the case when we have a pty | |
492 | * - there we cannot make difference between data sent to stdout and | |
493 | * stderr), indicate that we have seen an EOF from stderr. This way | |
494 | * we don\'t need to check the descriptor everywhere. | |
495 | */ | |
5260325f | 496 | if (fderr == -1) |
497 | fderr_eof = 1; | |
498 | ||
7368a6c8 | 499 | server_init_dispatch(); |
500 | ||
5260325f | 501 | /* Main loop of the server for the interactive session mode. */ |
502 | for (;;) { | |
5260325f | 503 | |
504 | /* Process buffered packets from the client. */ | |
505 | process_buffered_input_packets(); | |
506 | ||
aa3378df | 507 | /* |
508 | * If we have received eof, and there is no more pending | |
509 | * input data, cause a real eof by closing fdin. | |
510 | */ | |
5260325f | 511 | if (stdin_eof && fdin != -1 && buffer_len(&stdin_buffer) == 0) { |
8efc0c15 | 512 | #ifdef USE_PIPES |
5260325f | 513 | close(fdin); |
8efc0c15 | 514 | #else |
7368a6c8 | 515 | if (fdin != fdout) |
5260325f | 516 | close(fdin); |
517 | else | |
518 | shutdown(fdin, SHUT_WR); /* We will no longer send. */ | |
8efc0c15 | 519 | #endif |
5260325f | 520 | fdin = -1; |
521 | } | |
aa3378df | 522 | /* Make packets from buffered stderr data to send to the client. */ |
5260325f | 523 | make_packets_from_stderr_data(); |
524 | ||
aa3378df | 525 | /* |
526 | * Make packets from buffered stdout data to send to the | |
527 | * client. If there is very little to send, this arranges to | |
528 | * not send them now, but to wait a short while to see if we | |
529 | * are getting more data. This is necessary, as some systems | |
530 | * wake up readers from a pty after each separate character. | |
531 | */ | |
5260325f | 532 | max_time_milliseconds = 0; |
533 | stdout_buffer_bytes = buffer_len(&stdout_buffer); | |
534 | if (stdout_buffer_bytes != 0 && stdout_buffer_bytes < 256 && | |
535 | stdout_buffer_bytes != previous_stdout_buffer_bytes) { | |
536 | /* try again after a while */ | |
537 | max_time_milliseconds = 10; | |
538 | } else { | |
539 | /* Send it now. */ | |
540 | make_packets_from_stdout_data(); | |
541 | } | |
542 | previous_stdout_buffer_bytes = buffer_len(&stdout_buffer); | |
543 | ||
544 | /* Send channel data to the client. */ | |
545 | if (packet_not_very_much_data_to_write()) | |
546 | channel_output_poll(); | |
547 | ||
aa3378df | 548 | /* |
549 | * Bail out of the loop if the program has closed its output | |
550 | * descriptors, and we have no more data to send to the | |
551 | * client, and there is no pending buffered data. | |
552 | */ | |
7062c40f | 553 | if (fdout_eof && fderr_eof && !packet_have_data_to_write() && |
554 | buffer_len(&stdout_buffer) == 0 && buffer_len(&stderr_buffer) == 0) { | |
5260325f | 555 | if (!channel_still_open()) |
7368a6c8 | 556 | break; |
5260325f | 557 | if (!waiting_termination) { |
558 | const char *s = "Waiting for forwarded connections to terminate...\r\n"; | |
559 | char *cp; | |
560 | waiting_termination = 1; | |
561 | buffer_append(&stderr_buffer, s, strlen(s)); | |
562 | ||
563 | /* Display list of open channels. */ | |
564 | cp = channel_open_message(); | |
565 | buffer_append(&stderr_buffer, cp, strlen(cp)); | |
566 | xfree(cp); | |
567 | } | |
568 | } | |
569 | /* Sleep in select() until we can do something. */ | |
39929cdb | 570 | wait_until_can_do_something(&readset, &writeset, &max_fd, |
571 | max_time_milliseconds); | |
5260325f | 572 | |
573 | /* Process any channel events. */ | |
39929cdb | 574 | channel_after_select(readset, writeset); |
5260325f | 575 | |
576 | /* Process input from the client and from program stdout/stderr. */ | |
39929cdb | 577 | process_input(readset); |
5260325f | 578 | |
579 | /* Process output to the client and to program stdin. */ | |
39929cdb | 580 | process_output(writeset); |
8efc0c15 | 581 | } |
39929cdb | 582 | if (readset) |
583 | xfree(readset); | |
584 | if (writeset) | |
585 | xfree(writeset); | |
8efc0c15 | 586 | |
5260325f | 587 | /* Cleanup and termination code. */ |
8efc0c15 | 588 | |
5260325f | 589 | /* Wait until all output has been sent to the client. */ |
590 | drain_output(); | |
8efc0c15 | 591 | |
5260325f | 592 | debug("End of interactive session; stdin %ld, stdout (read %ld, sent %ld), stderr %ld bytes.", |
593 | stdin_bytes, fdout_bytes, stdout_bytes, stderr_bytes); | |
8efc0c15 | 594 | |
5260325f | 595 | /* Free and clear the buffers. */ |
596 | buffer_free(&stdin_buffer); | |
597 | buffer_free(&stdout_buffer); | |
598 | buffer_free(&stderr_buffer); | |
8efc0c15 | 599 | |
5260325f | 600 | /* Close the file descriptors. */ |
601 | if (fdout != -1) | |
602 | close(fdout); | |
603 | fdout = -1; | |
604 | fdout_eof = 1; | |
605 | if (fderr != -1) | |
606 | close(fderr); | |
607 | fderr = -1; | |
608 | fderr_eof = 1; | |
609 | if (fdin != -1) | |
610 | close(fdin); | |
611 | fdin = -1; | |
612 | ||
d6746a0b | 613 | channel_free_all(); |
5260325f | 614 | |
5260325f | 615 | /* We no longer want our SIGCHLD handler to be called. */ |
616 | signal(SIGCHLD, SIG_DFL); | |
617 | ||
c9130033 | 618 | wait_pid = waitpid(-1, &wait_status, child_terminated ? WNOHANG : 0); |
619 | if (wait_pid == -1) | |
620 | packet_disconnect("wait: %.100s", strerror(errno)); | |
621 | else if (wait_pid != pid) | |
622 | error("Strange, wait returned pid %d, expected %d", | |
623 | wait_pid, pid); | |
624 | ||
5260325f | 625 | /* Check if it exited normally. */ |
626 | if (WIFEXITED(wait_status)) { | |
627 | /* Yes, normal exit. Get exit status and send it to the client. */ | |
628 | debug("Command exited with status %d.", WEXITSTATUS(wait_status)); | |
629 | packet_start(SSH_SMSG_EXITSTATUS); | |
630 | packet_put_int(WEXITSTATUS(wait_status)); | |
631 | packet_send(); | |
632 | packet_write_wait(); | |
633 | ||
aa3378df | 634 | /* |
635 | * Wait for exit confirmation. Note that there might be | |
636 | * other packets coming before it; however, the program has | |
637 | * already died so we just ignore them. The client is | |
638 | * supposed to respond with the confirmation when it receives | |
639 | * the exit status. | |
640 | */ | |
5260325f | 641 | do { |
642 | int plen; | |
643 | type = packet_read(&plen); | |
644 | } | |
645 | while (type != SSH_CMSG_EXIT_CONFIRMATION); | |
646 | ||
647 | debug("Received exit confirmation."); | |
648 | return; | |
649 | } | |
650 | /* Check if the program terminated due to a signal. */ | |
651 | if (WIFSIGNALED(wait_status)) | |
652 | packet_disconnect("Command terminated on signal %d.", | |
653 | WTERMSIG(wait_status)); | |
654 | ||
655 | /* Some weird exit cause. Just exit. */ | |
656 | packet_disconnect("wait returned status %04x.", wait_status); | |
657 | /* NOTREACHED */ | |
658 | } | |
7368a6c8 | 659 | |
6ae2364d | 660 | void |
e78a59f5 | 661 | server_loop2(void) |
662 | { | |
39929cdb | 663 | fd_set *readset = NULL, *writeset = NULL; |
cc94bd38 | 664 | int rekeying = 0, max_fd, status; |
e78a59f5 | 665 | pid_t pid; |
666 | ||
667 | debug("Entering interactive session for SSH2."); | |
668 | ||
c9130033 | 669 | mysignal(SIGCHLD, sigchld_handler); |
e78a59f5 | 670 | child_terminated = 0; |
671 | connection_in = packet_get_connection_in(); | |
672 | connection_out = packet_get_connection_out(); | |
39929cdb | 673 | |
674 | max_fd = MAX(connection_in, connection_out); | |
675 | ||
e78a59f5 | 676 | server_init_dispatch(); |
677 | ||
678 | for (;;) { | |
679 | process_buffered_input_packets(); | |
bbb4cc1b | 680 | |
cd332296 | 681 | rekeying = (xxx_kex != NULL && !xxx_kex->done); |
bbb4cc1b | 682 | |
bbb4cc1b | 683 | if (!rekeying && packet_not_very_much_data_to_write()) |
e78a59f5 | 684 | channel_output_poll(); |
bbb4cc1b | 685 | wait_until_can_do_something(&readset, &writeset, &max_fd, |
686 | rekeying); | |
7062c40f | 687 | if (child_terminated) { |
e78a59f5 | 688 | while ((pid = waitpid(-1, &status, WNOHANG)) > 0) |
689 | session_close_by_pid(pid, status); | |
690 | child_terminated = 0; | |
691 | } | |
bbb4cc1b | 692 | if (!rekeying) |
693 | channel_after_select(readset, writeset); | |
39929cdb | 694 | process_input(readset); |
cc94bd38 | 695 | if (connection_closed) |
696 | break; | |
39929cdb | 697 | process_output(writeset); |
e78a59f5 | 698 | } |
39929cdb | 699 | if (readset) |
700 | xfree(readset); | |
701 | if (writeset) | |
702 | xfree(writeset); | |
703 | ||
d6746a0b | 704 | channel_free_all(); |
705 | ||
e78a59f5 | 706 | signal(SIGCHLD, SIG_DFL); |
707 | while ((pid = waitpid(-1, &status, WNOHANG)) > 0) | |
708 | session_close_by_pid(pid, status); | |
e78a59f5 | 709 | } |
710 | ||
396c147e | 711 | static void |
3ffc6336 | 712 | server_input_channel_failure(int type, int plen, void *ctxt) |
713 | { | |
714 | debug("Got CHANNEL_FAILURE for keepalive"); | |
715 | /* | |
39aefe7b | 716 | * reset timeout, since we got a sane answer from the client. |
3ffc6336 | 717 | * even if this was generated by something other than |
718 | * the bogus CHANNEL_REQUEST we send for keepalives. | |
719 | */ | |
720 | client_alive_timeouts = 0; | |
721 | } | |
722 | ||
723 | ||
396c147e | 724 | static void |
188adeb2 | 725 | server_input_stdin_data(int type, int plen, void *ctxt) |
7368a6c8 | 726 | { |
727 | char *data; | |
1e3b8b07 | 728 | u_int data_len; |
7368a6c8 | 729 | |
730 | /* Stdin data from the client. Append it to the buffer. */ | |
731 | /* Ignore any data if the client has closed stdin. */ | |
732 | if (fdin == -1) | |
733 | return; | |
734 | data = packet_get_string(&data_len); | |
735 | packet_integrity_check(plen, (4 + data_len), type); | |
736 | buffer_append(&stdin_buffer, data, data_len); | |
737 | memset(data, 0, data_len); | |
738 | xfree(data); | |
739 | } | |
740 | ||
396c147e | 741 | static void |
188adeb2 | 742 | server_input_eof(int type, int plen, void *ctxt) |
7368a6c8 | 743 | { |
744 | /* | |
745 | * Eof from the client. The stdin descriptor to the | |
746 | * program will be closed when all buffered data has | |
747 | * drained. | |
748 | */ | |
749 | debug("EOF received for stdin."); | |
750 | packet_integrity_check(plen, 0, type); | |
751 | stdin_eof = 1; | |
752 | } | |
753 | ||
396c147e | 754 | static void |
188adeb2 | 755 | server_input_window_size(int type, int plen, void *ctxt) |
7368a6c8 | 756 | { |
757 | int row = packet_get_int(); | |
758 | int col = packet_get_int(); | |
759 | int xpixel = packet_get_int(); | |
760 | int ypixel = packet_get_int(); | |
761 | ||
762 | debug("Window change received."); | |
763 | packet_integrity_check(plen, 4 * 4, type); | |
764 | if (fdin != -1) | |
765 | pty_change_window_size(fdin, row, col, xpixel, ypixel); | |
766 | } | |
767 | ||
396c147e | 768 | static Channel * |
fa08c86b | 769 | server_request_direct_tcpip(char *ctype) |
e78a59f5 | 770 | { |
719fc62f | 771 | Channel *c; |
772 | int sock; | |
6ae2364d | 773 | char *target, *originator; |
774 | int target_port, originator_port; | |
e78a59f5 | 775 | |
6ae2364d | 776 | target = packet_get_string(NULL); |
777 | target_port = packet_get_int(); | |
e78a59f5 | 778 | originator = packet_get_string(NULL); |
779 | originator_port = packet_get_int(); | |
6ae2364d | 780 | packet_done(); |
71276795 | 781 | |
fa08c86b | 782 | debug("server_request_direct_tcpip: originator %s port %d, target %s port %d", |
71276795 | 783 | originator, originator_port, target, target_port); |
38c295d6 | 784 | |
e78a59f5 | 785 | /* XXX check permission */ |
6ae2364d | 786 | sock = channel_connect_to(target, target_port); |
787 | xfree(target); | |
e78a59f5 | 788 | xfree(originator); |
789 | if (sock < 0) | |
fa08c86b | 790 | return NULL; |
719fc62f | 791 | c = channel_new(ctype, SSH_CHANNEL_CONNECTING, |
bcbf86ec | 792 | sock, sock, -1, CHAN_TCP_WINDOW_DEFAULT, |
a22aff1f | 793 | CHAN_TCP_PACKET_DEFAULT, 0, xstrdup("direct-tcpip"), 1); |
719fc62f | 794 | if (c == NULL) { |
795 | error("server_request_direct_tcpip: channel_new failed"); | |
796 | close(sock); | |
797 | } | |
798 | return c; | |
fa08c86b | 799 | } |
800 | ||
396c147e | 801 | static Channel * |
fa08c86b | 802 | server_request_session(char *ctype) |
803 | { | |
719fc62f | 804 | Channel *c; |
fa08c86b | 805 | |
806 | debug("input_session_request"); | |
807 | packet_done(); | |
808 | /* | |
809 | * A server session has no fd to read or write until a | |
810 | * CHANNEL_REQUEST for a shell is made, so we set the type to | |
811 | * SSH_CHANNEL_LARVAL. Additionally, a callback for handling all | |
812 | * CHANNEL_REQUEST messages is registered. | |
813 | */ | |
719fc62f | 814 | c = channel_new(ctype, SSH_CHANNEL_LARVAL, |
815 | -1, -1, -1, /*window size*/0, CHAN_SES_PACKET_DEFAULT, | |
fa08c86b | 816 | 0, xstrdup("server-session"), 1); |
719fc62f | 817 | if (c == NULL) { |
818 | error("server_request_session: channel_new failed"); | |
819 | return NULL; | |
820 | } | |
821 | if (session_open(c->self) != 1) { | |
822 | debug("session open failed, free channel %d", c->self); | |
823 | channel_free(c); | |
824 | return NULL; | |
fa08c86b | 825 | } |
719fc62f | 826 | channel_register_callback(c->self, SSH2_MSG_CHANNEL_REQUEST, |
827 | session_input_channel_req, (void *)0); | |
828 | channel_register_cleanup(c->self, session_close_by_channel); | |
829 | return c; | |
e78a59f5 | 830 | } |
831 | ||
396c147e | 832 | static void |
188adeb2 | 833 | server_input_channel_open(int type, int plen, void *ctxt) |
e78a59f5 | 834 | { |
835 | Channel *c = NULL; | |
836 | char *ctype; | |
1e3b8b07 | 837 | u_int len; |
e78a59f5 | 838 | int rchan; |
839 | int rmaxpack; | |
840 | int rwindow; | |
841 | ||
842 | ctype = packet_get_string(&len); | |
843 | rchan = packet_get_int(); | |
844 | rwindow = packet_get_int(); | |
845 | rmaxpack = packet_get_int(); | |
846 | ||
188adeb2 | 847 | debug("server_input_channel_open: ctype %s rchan %d win %d max %d", |
e78a59f5 | 848 | ctype, rchan, rwindow, rmaxpack); |
849 | ||
850 | if (strcmp(ctype, "session") == 0) { | |
fa08c86b | 851 | c = server_request_session(ctype); |
e78a59f5 | 852 | } else if (strcmp(ctype, "direct-tcpip") == 0) { |
fa08c86b | 853 | c = server_request_direct_tcpip(ctype); |
e78a59f5 | 854 | } |
855 | if (c != NULL) { | |
fa08c86b | 856 | debug("server_input_channel_open: confirm %s", ctype); |
e78a59f5 | 857 | c->remote_id = rchan; |
858 | c->remote_window = rwindow; | |
859 | c->remote_maxpacket = rmaxpack; | |
d18e0850 | 860 | if (c->type != SSH_CHANNEL_CONNECTING) { |
861 | packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION); | |
862 | packet_put_int(c->remote_id); | |
863 | packet_put_int(c->self); | |
864 | packet_put_int(c->local_window); | |
865 | packet_put_int(c->local_maxpacket); | |
866 | packet_send(); | |
867 | } | |
e78a59f5 | 868 | } else { |
fa08c86b | 869 | debug("server_input_channel_open: failure %s", ctype); |
e78a59f5 | 870 | packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE); |
871 | packet_put_int(rchan); | |
872 | packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED); | |
fbe90f7b | 873 | if (!(datafellows & SSH_BUG_OPENFAILURE)) { |
d18e0850 | 874 | packet_put_cstring("open failed"); |
fbe90f7b | 875 | packet_put_cstring(""); |
876 | } | |
e78a59f5 | 877 | packet_send(); |
878 | } | |
879 | xfree(ctype); | |
880 | } | |
881 | ||
396c147e | 882 | static void |
fa08c86b | 883 | server_input_global_request(int type, int plen, void *ctxt) |
884 | { | |
885 | char *rtype; | |
886 | int want_reply; | |
887 | int success = 0; | |
888 | ||
889 | rtype = packet_get_string(NULL); | |
890 | want_reply = packet_get_char(); | |
891 | debug("server_input_global_request: rtype %s want_reply %d", rtype, want_reply); | |
2b87da3b | 892 | |
01794848 | 893 | /* -R style forwarding */ |
fa08c86b | 894 | if (strcmp(rtype, "tcpip-forward") == 0) { |
895 | struct passwd *pw; | |
896 | char *listen_address; | |
897 | u_short listen_port; | |
898 | ||
899 | pw = auth_get_user(); | |
900 | if (pw == NULL) | |
901 | fatal("server_input_global_request: no user"); | |
902 | listen_address = packet_get_string(NULL); /* XXX currently ignored */ | |
903 | listen_port = (u_short)packet_get_int(); | |
904 | debug("server_input_global_request: tcpip-forward listen %s port %d", | |
905 | listen_address, listen_port); | |
906 | ||
907 | /* check permissions */ | |
908 | if (!options.allow_tcp_forwarding || | |
909 | no_port_forwarding_flag || | |
910 | (listen_port < IPPORT_RESERVED && pw->pw_uid != 0)) { | |
911 | success = 0; | |
912 | packet_send_debug("Server has disabled port forwarding."); | |
913 | } else { | |
914 | /* Start listening on the port */ | |
02a024dd | 915 | success = channel_request_forwarding( |
fa08c86b | 916 | listen_address, listen_port, |
917 | /*unspec host_to_connect*/ "<unspec host>", | |
918 | /*unspec port_to_connect*/ 0, | |
919 | options.gateway_ports, /*remote*/ 1); | |
fa08c86b | 920 | } |
921 | xfree(listen_address); | |
922 | } | |
923 | if (want_reply) { | |
924 | packet_start(success ? | |
925 | SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE); | |
926 | packet_send(); | |
927 | packet_write_wait(); | |
928 | } | |
929 | xfree(rtype); | |
930 | } | |
931 | ||
396c147e | 932 | static void |
5ca51e19 | 933 | server_init_dispatch_20(void) |
e78a59f5 | 934 | { |
935 | debug("server_init_dispatch_20"); | |
936 | dispatch_init(&dispatch_protocol_error); | |
937 | dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose); | |
938 | dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data); | |
939 | dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof); | |
940 | dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data); | |
941 | dispatch_set(SSH2_MSG_CHANNEL_OPEN, &server_input_channel_open); | |
942 | dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); | |
943 | dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); | |
944 | dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &channel_input_channel_request); | |
945 | dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust); | |
fa08c86b | 946 | dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &server_input_global_request); |
3ffc6336 | 947 | /* client_alive */ |
948 | dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &server_input_channel_failure); | |
7a37c112 | 949 | /* rekeying */ |
950 | dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit); | |
e78a59f5 | 951 | } |
396c147e | 952 | static void |
5ca51e19 | 953 | server_init_dispatch_13(void) |
7368a6c8 | 954 | { |
955 | debug("server_init_dispatch_13"); | |
956 | dispatch_init(NULL); | |
957 | dispatch_set(SSH_CMSG_EOF, &server_input_eof); | |
958 | dispatch_set(SSH_CMSG_STDIN_DATA, &server_input_stdin_data); | |
959 | dispatch_set(SSH_CMSG_WINDOW_SIZE, &server_input_window_size); | |
960 | dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close); | |
961 | dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation); | |
962 | dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data); | |
963 | dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); | |
964 | dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); | |
965 | dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open); | |
966 | } | |
396c147e | 967 | static void |
5ca51e19 | 968 | server_init_dispatch_15(void) |
7368a6c8 | 969 | { |
970 | server_init_dispatch_13(); | |
971 | debug("server_init_dispatch_15"); | |
972 | dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof); | |
973 | dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_oclose); | |
974 | } | |
396c147e | 975 | static void |
5ca51e19 | 976 | server_init_dispatch(void) |
7368a6c8 | 977 | { |
e78a59f5 | 978 | if (compat20) |
979 | server_init_dispatch_20(); | |
980 | else if (compat13) | |
7368a6c8 | 981 | server_init_dispatch_13(); |
982 | else | |
983 | server_init_dispatch_15(); | |
984 | } | |
3ffc6336 | 985 |