blob: 25320348b527237f322b7dae32c39d60187cf079 [file] [log] [blame]
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001/*
Damien Miller95def091999-11-25 00:26:21 +11002 * Author: Tatu Ylonen <ylo@cs.hut.fi>
3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
4 * All rights reserved
Damien Miller95def091999-11-25 00:26:21 +11005 * Server main loop for handling the interactive session.
Damien Millere4340be2000-09-16 13:29:08 +11006 *
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 *
Damien Millerefb4afe2000-04-12 18:45:05 +100013 * SSH2 support by Markus Friedl.
14 * Copyright (c) 2000 Markus Friedl. All rights reserved.
Damien Millere4340be2000-09-16 13:29:08 +110015 *
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.
Damien Millerefb4afe2000-04-12 18:45:05 +100035 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100036
37#include "includes.h"
38#include "xmalloc.h"
39#include "ssh.h"
40#include "packet.h"
41#include "buffer.h"
42#include "servconf.h"
43#include "pty.h"
Damien Millerb38eff82000-04-01 11:09:21 +100044#include "channels.h"
45
46#include "compat.h"
Damien Millerefb4afe2000-04-12 18:45:05 +100047#include "ssh2.h"
48#include "session.h"
Damien Millerb38eff82000-04-01 11:09:21 +100049#include "dispatch.h"
Damien Millerf6d9e222000-06-18 14:50:44 +100050#include "auth-options.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100051
52static Buffer stdin_buffer; /* Buffer for stdin data. */
53static Buffer stdout_buffer; /* Buffer for stdout data. */
54static Buffer stderr_buffer; /* Buffer for stderr data. */
55static int fdin; /* Descriptor for stdin (for writing) */
56static int fdout; /* Descriptor for stdout (for reading);
57 May be same number as fdin. */
58static int fderr; /* Descriptor for stderr. May be -1. */
59static long stdin_bytes = 0; /* Number of bytes written to stdin. */
60static long stdout_bytes = 0; /* Number of stdout bytes sent to client. */
61static long stderr_bytes = 0; /* Number of stderr bytes sent to client. */
62static long fdout_bytes = 0; /* Number of stdout bytes read from program. */
63static int stdin_eof = 0; /* EOF message received from client. */
64static int fdout_eof = 0; /* EOF encountered reading from fdout. */
65static int fderr_eof = 0; /* EOF encountered readung from fderr. */
66static int connection_in; /* Connection to client (input). */
67static int connection_out; /* Connection to client (output). */
68static unsigned int buffer_high;/* "Soft" max buffer size. */
69static int max_fd; /* Max file descriptor number for select(). */
70
Damien Miller5428f641999-11-25 11:54:57 +110071/*
72 * This SIGCHLD kludge is used to detect when the child exits. The server
73 * will exit after that, as soon as forwarded connections have terminated.
Damien Millerb284b542000-01-17 20:55:18 +110074 *
75 * After SIGCHLD child_has_selected is set to 1 after the first pass
76 * through the wait_until_can_do_something() select(). This ensures
77 * that the child's output gets a chance to drain before it is yanked.
Damien Miller5428f641999-11-25 11:54:57 +110078 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100079
Damien Miller166fca82000-04-20 07:42:21 +100080static pid_t child_pid; /* Pid of the child. */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100081static volatile int child_terminated; /* The child has terminated. */
Damien Millerb284b542000-01-17 20:55:18 +110082static volatile int child_has_selected; /* Child has had chance to drain. */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100083static volatile int child_wait_status; /* Status from wait(). */
84
Damien Millerb38eff82000-04-01 11:09:21 +100085void server_init_dispatch(void);
86
Damien Miller4af51302000-04-16 11:18:38 +100087void
Damien Miller95def091999-11-25 00:26:21 +110088sigchld_handler(int sig)
Damien Millerd4a8b7e1999-10-27 13:42:43 +100089{
Damien Miller95def091999-11-25 00:26:21 +110090 int save_errno = errno;
Damien Miller166fca82000-04-20 07:42:21 +100091 pid_t wait_pid;
92
Damien Miller95def091999-11-25 00:26:21 +110093 debug("Received SIGCHLD.");
94 wait_pid = wait((int *) &child_wait_status);
95 if (wait_pid != -1) {
96 if (wait_pid != child_pid)
97 error("Strange, got SIGCHLD and wait returned pid %d but child is %d",
98 wait_pid, child_pid);
99 if (WIFEXITED(child_wait_status) ||
100 WIFSIGNALED(child_wait_status))
101 child_terminated = 1;
Damien Millerb284b542000-01-17 20:55:18 +1100102 child_has_selected = 0;
Damien Miller95def091999-11-25 00:26:21 +1100103 }
104 signal(SIGCHLD, sigchld_handler);
105 errno = save_errno;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000106}
Damien Miller4af51302000-04-16 11:18:38 +1000107void
Damien Millerefb4afe2000-04-12 18:45:05 +1000108sigchld_handler2(int sig)
109{
110 int save_errno = errno;
111 debug("Received SIGCHLD.");
112 child_terminated = 1;
Damien Millerefb4afe2000-04-12 18:45:05 +1000113 errno = save_errno;
114}
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000115
Damien Miller95def091999-11-25 00:26:21 +1100116/*
Damien Miller95def091999-11-25 00:26:21 +1100117 * Make packets from buffered stderr data, and buffer it for sending
118 * to the client.
119 */
Damien Miller4af51302000-04-16 11:18:38 +1000120void
Damien Miller95def091999-11-25 00:26:21 +1100121make_packets_from_stderr_data()
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000122{
Damien Miller95def091999-11-25 00:26:21 +1100123 int len;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000124
Damien Miller95def091999-11-25 00:26:21 +1100125 /* Send buffered stderr data to the client. */
126 while (buffer_len(&stderr_buffer) > 0 &&
Damien Miller037a0dc1999-12-07 15:38:31 +1100127 packet_not_very_much_data_to_write()) {
Damien Miller95def091999-11-25 00:26:21 +1100128 len = buffer_len(&stderr_buffer);
129 if (packet_is_interactive()) {
130 if (len > 512)
131 len = 512;
132 } else {
133 /* Keep the packets at reasonable size. */
134 if (len > packet_get_maxsize())
135 len = packet_get_maxsize();
136 }
137 packet_start(SSH_SMSG_STDERR_DATA);
138 packet_put_string(buffer_ptr(&stderr_buffer), len);
139 packet_send();
140 buffer_consume(&stderr_buffer, len);
141 stderr_bytes += len;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000142 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000143}
144
Damien Miller95def091999-11-25 00:26:21 +1100145/*
146 * Make packets from buffered stdout data, and buffer it for sending to the
147 * client.
148 */
Damien Miller4af51302000-04-16 11:18:38 +1000149void
Damien Miller95def091999-11-25 00:26:21 +1100150make_packets_from_stdout_data()
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000151{
Damien Miller95def091999-11-25 00:26:21 +1100152 int len;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000153
Damien Miller95def091999-11-25 00:26:21 +1100154 /* Send buffered stdout data to the client. */
155 while (buffer_len(&stdout_buffer) > 0 &&
Damien Miller037a0dc1999-12-07 15:38:31 +1100156 packet_not_very_much_data_to_write()) {
Damien Miller95def091999-11-25 00:26:21 +1100157 len = buffer_len(&stdout_buffer);
158 if (packet_is_interactive()) {
159 if (len > 512)
160 len = 512;
161 } else {
162 /* Keep the packets at reasonable size. */
163 if (len > packet_get_maxsize())
164 len = packet_get_maxsize();
165 }
166 packet_start(SSH_SMSG_STDOUT_DATA);
167 packet_put_string(buffer_ptr(&stdout_buffer), len);
168 packet_send();
169 buffer_consume(&stdout_buffer, len);
170 stdout_bytes += len;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000171 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000172}
173
Damien Miller95def091999-11-25 00:26:21 +1100174/*
175 * Sleep in select() until we can do something. This will initialize the
176 * select masks. Upon return, the masks will indicate which descriptors
177 * have data or can accept data. Optionally, a maximum time can be specified
178 * for the duration of the wait (0 = infinite).
179 */
Damien Miller4af51302000-04-16 11:18:38 +1000180void
Damien Miller95def091999-11-25 00:26:21 +1100181wait_until_can_do_something(fd_set * readset, fd_set * writeset,
182 unsigned int max_time_milliseconds)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000183{
Damien Miller95def091999-11-25 00:26:21 +1100184 struct timeval tv, *tvp;
185 int ret;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000186
Damien Miller95def091999-11-25 00:26:21 +1100187 /* When select fails we restart from here. */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000188retry_select:
189
Damien Miller95def091999-11-25 00:26:21 +1100190 /* Initialize select() masks. */
191 FD_ZERO(readset);
Damien Millerb1715dc2000-05-30 13:44:51 +1000192 FD_ZERO(writeset);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000193
Damien Millerefb4afe2000-04-12 18:45:05 +1000194 if (compat20) {
Damien Millere247cc42000-05-07 12:03:14 +1000195 /* wrong: bad condition XXX */
Damien Millerefb4afe2000-04-12 18:45:05 +1000196 if (channel_not_very_much_buffered_data())
197 FD_SET(connection_in, readset);
198 } else {
Damien Millerb1715dc2000-05-30 13:44:51 +1000199 /*
200 * Read packets from the client unless we have too much
201 * buffered stdin or channel data.
202 */
203 if (buffer_len(&stdin_buffer) < buffer_high &&
Damien Millerefb4afe2000-04-12 18:45:05 +1000204 channel_not_very_much_buffered_data())
205 FD_SET(connection_in, readset);
Damien Millerb1715dc2000-05-30 13:44:51 +1000206 /*
207 * If there is not too much data already buffered going to
208 * the client, try to get some more data from the program.
209 */
210 if (packet_not_very_much_data_to_write()) {
211 if (!fdout_eof)
212 FD_SET(fdout, readset);
213 if (!fderr_eof)
214 FD_SET(fderr, readset);
215 }
216 /*
217 * If we have buffered data, try to write some of that data
218 * to the program.
219 */
220 if (fdin != -1 && buffer_len(&stdin_buffer) > 0)
221 FD_SET(fdin, writeset);
Damien Millerefb4afe2000-04-12 18:45:05 +1000222 }
Damien Miller95def091999-11-25 00:26:21 +1100223 /* Set masks for channel descriptors. */
224 channel_prepare_select(readset, writeset);
225
Damien Miller5428f641999-11-25 11:54:57 +1100226 /*
227 * If we have buffered packet data going to the client, mark that
228 * descriptor.
229 */
Damien Miller95def091999-11-25 00:26:21 +1100230 if (packet_have_data_to_write())
231 FD_SET(connection_out, writeset);
232
Damien Miller95def091999-11-25 00:26:21 +1100233 /* Update the maximum descriptor number if appropriate. */
234 if (channel_max_fd() > max_fd)
235 max_fd = channel_max_fd();
236
Damien Miller5428f641999-11-25 11:54:57 +1100237 /*
238 * If child has terminated and there is enough buffer space to read
239 * from it, then read as much as is available and exit.
240 */
Damien Miller95def091999-11-25 00:26:21 +1100241 if (child_terminated && packet_not_very_much_data_to_write())
242 if (max_time_milliseconds == 0)
243 max_time_milliseconds = 100;
244
245 if (max_time_milliseconds == 0)
246 tvp = NULL;
247 else {
248 tv.tv_sec = max_time_milliseconds / 1000;
249 tv.tv_usec = 1000 * (max_time_milliseconds % 1000);
250 tvp = &tv;
251 }
Damien Millerefb4afe2000-04-12 18:45:05 +1000252 if (tvp!=NULL)
253 debug("tvp!=NULL kid %d mili %d", child_terminated, max_time_milliseconds);
Damien Miller95def091999-11-25 00:26:21 +1100254
255 /* Wait for something to happen, or the timeout to expire. */
256 ret = select(max_fd + 1, readset, writeset, NULL, tvp);
257
258 if (ret < 0) {
259 if (errno != EINTR)
260 error("select: %.100s", strerror(errno));
261 else
262 goto retry_select;
263 }
Damien Millerb284b542000-01-17 20:55:18 +1100264
265 if (child_terminated)
266 child_has_selected = 1;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000267}
268
Damien Miller95def091999-11-25 00:26:21 +1100269/*
270 * Processes input from the client and the program. Input data is stored
271 * in buffers and processed later.
272 */
Damien Miller4af51302000-04-16 11:18:38 +1000273void
Damien Miller95def091999-11-25 00:26:21 +1100274process_input(fd_set * readset)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000275{
Damien Miller95def091999-11-25 00:26:21 +1100276 int len;
277 char buf[16384];
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000278
Damien Miller95def091999-11-25 00:26:21 +1100279 /* Read and buffer any input data from the client. */
280 if (FD_ISSET(connection_in, readset)) {
281 len = read(connection_in, buf, sizeof(buf));
282 if (len == 0) {
283 verbose("Connection closed by remote host.");
284 fatal_cleanup();
Damien Millerdcb6ecd2000-05-17 22:34:22 +1000285 } else if (len < 0) {
286 if (errno != EINTR && errno != EAGAIN) {
287 verbose("Read error from remote host: %.100s", strerror(errno));
288 fatal_cleanup();
289 }
290 } else {
291 /* Buffer any received data. */
292 packet_process_incoming(buf, len);
Damien Miller95def091999-11-25 00:26:21 +1100293 }
Damien Miller95def091999-11-25 00:26:21 +1100294 }
Damien Millerefb4afe2000-04-12 18:45:05 +1000295 if (compat20)
296 return;
297
Damien Miller95def091999-11-25 00:26:21 +1100298 /* Read and buffer any available stdout data from the program. */
299 if (!fdout_eof && FD_ISSET(fdout, readset)) {
300 len = read(fdout, buf, sizeof(buf));
Damien Millerdcb6ecd2000-05-17 22:34:22 +1000301 if (len < 0 && (errno == EINTR || errno == EAGAIN)) {
302 /* do nothing */
303 } else if (len <= 0) {
Damien Miller95def091999-11-25 00:26:21 +1100304 fdout_eof = 1;
Damien Millerdcb6ecd2000-05-17 22:34:22 +1000305 } else {
Damien Miller95def091999-11-25 00:26:21 +1100306 buffer_append(&stdout_buffer, buf, len);
307 fdout_bytes += len;
308 }
309 }
310 /* Read and buffer any available stderr data from the program. */
311 if (!fderr_eof && FD_ISSET(fderr, readset)) {
312 len = read(fderr, buf, sizeof(buf));
Damien Millerdcb6ecd2000-05-17 22:34:22 +1000313 if (len < 0 && (errno == EINTR || errno == EAGAIN)) {
314 /* do nothing */
315 } else if (len <= 0) {
Damien Miller95def091999-11-25 00:26:21 +1100316 fderr_eof = 1;
Damien Millerdcb6ecd2000-05-17 22:34:22 +1000317 } else {
Damien Miller95def091999-11-25 00:26:21 +1100318 buffer_append(&stderr_buffer, buf, len);
Damien Millerdcb6ecd2000-05-17 22:34:22 +1000319 }
Damien Miller95def091999-11-25 00:26:21 +1100320 }
321}
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000322
Damien Miller95def091999-11-25 00:26:21 +1100323/*
324 * Sends data from internal buffers to client program stdin.
325 */
Damien Miller4af51302000-04-16 11:18:38 +1000326void
Damien Miller95def091999-11-25 00:26:21 +1100327process_output(fd_set * writeset)
328{
329 int len;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000330
Damien Miller95def091999-11-25 00:26:21 +1100331 /* Write buffered data to program stdin. */
Damien Millerefb4afe2000-04-12 18:45:05 +1000332 if (!compat20 && fdin != -1 && FD_ISSET(fdin, writeset)) {
Damien Miller95def091999-11-25 00:26:21 +1100333 len = write(fdin, buffer_ptr(&stdin_buffer),
Damien Miller037a0dc1999-12-07 15:38:31 +1100334 buffer_len(&stdin_buffer));
Damien Millerdcb6ecd2000-05-17 22:34:22 +1000335 if (len < 0 && (errno == EINTR || errno == EAGAIN)) {
336 /* do nothing */
337 } else if (len <= 0) {
Damien Miller95def091999-11-25 00:26:21 +1100338#ifdef USE_PIPES
339 close(fdin);
340#else
Damien Millerb38eff82000-04-01 11:09:21 +1000341 if (fdin != fdout)
Damien Miller95def091999-11-25 00:26:21 +1100342 close(fdin);
343 else
344 shutdown(fdin, SHUT_WR); /* We will no longer send. */
345#endif
346 fdin = -1;
347 } else {
348 /* Successful write. Consume the data from the buffer. */
349 buffer_consume(&stdin_buffer, len);
350 /* Update the count of bytes written to the program. */
351 stdin_bytes += len;
352 }
353 }
354 /* Send any buffered packet data to the client. */
355 if (FD_ISSET(connection_out, writeset))
356 packet_write_poll();
357}
358
359/*
360 * Wait until all buffered output has been sent to the client.
361 * This is used when the program terminates.
362 */
Damien Miller4af51302000-04-16 11:18:38 +1000363void
Damien Miller95def091999-11-25 00:26:21 +1100364drain_output()
365{
366 /* Send any buffered stdout data to the client. */
367 if (buffer_len(&stdout_buffer) > 0) {
368 packet_start(SSH_SMSG_STDOUT_DATA);
369 packet_put_string(buffer_ptr(&stdout_buffer),
370 buffer_len(&stdout_buffer));
371 packet_send();
372 /* Update the count of sent bytes. */
373 stdout_bytes += buffer_len(&stdout_buffer);
374 }
375 /* Send any buffered stderr data to the client. */
376 if (buffer_len(&stderr_buffer) > 0) {
377 packet_start(SSH_SMSG_STDERR_DATA);
378 packet_put_string(buffer_ptr(&stderr_buffer),
379 buffer_len(&stderr_buffer));
380 packet_send();
381 /* Update the count of sent bytes. */
382 stderr_bytes += buffer_len(&stderr_buffer);
383 }
384 /* Wait until all buffered data has been written to the client. */
385 packet_write_wait();
386}
387
Damien Miller4af51302000-04-16 11:18:38 +1000388void
Damien Millerb38eff82000-04-01 11:09:21 +1000389process_buffered_input_packets()
390{
Damien Miller62cee002000-09-23 17:15:56 +1100391 dispatch_run(DISPATCH_NONBLOCK, NULL, NULL);
Damien Millerb38eff82000-04-01 11:09:21 +1000392}
393
Damien Miller95def091999-11-25 00:26:21 +1100394/*
395 * Performs the interactive session. This handles data transmission between
396 * the client and the program. Note that the notion of stdin, stdout, and
397 * stderr in this function is sort of reversed: this function writes to
398 * stdin (of the child program), and reads from stdout and stderr (of the
399 * child program).
400 */
Damien Miller4af51302000-04-16 11:18:38 +1000401void
Damien Miller166fca82000-04-20 07:42:21 +1000402server_loop(pid_t pid, int fdin_arg, int fdout_arg, int fderr_arg)
Damien Miller95def091999-11-25 00:26:21 +1100403{
Damien Millerb1715dc2000-05-30 13:44:51 +1000404 fd_set readset, writeset;
Damien Miller166fca82000-04-20 07:42:21 +1000405 int wait_status; /* Status returned by wait(). */
406 pid_t wait_pid; /* pid returned by wait(). */
Damien Miller95def091999-11-25 00:26:21 +1100407 int waiting_termination = 0; /* Have displayed waiting close message. */
408 unsigned int max_time_milliseconds;
409 unsigned int previous_stdout_buffer_bytes;
410 unsigned int stdout_buffer_bytes;
411 int type;
412
413 debug("Entering interactive session.");
414
415 /* Initialize the SIGCHLD kludge. */
416 child_pid = pid;
417 child_terminated = 0;
Damien Millerb284b542000-01-17 20:55:18 +1100418 child_has_selected = 0;
Damien Miller95def091999-11-25 00:26:21 +1100419 signal(SIGCHLD, sigchld_handler);
Damien Millercf3888d2000-09-30 14:17:52 +1100420 signal(SIGPIPE, SIG_IGN);
Damien Miller95def091999-11-25 00:26:21 +1100421
422 /* Initialize our global variables. */
423 fdin = fdin_arg;
424 fdout = fdout_arg;
425 fderr = fderr_arg;
Damien Millerdcb6ecd2000-05-17 22:34:22 +1000426
427 /* nonblocking IO */
428 set_nonblock(fdin);
429 set_nonblock(fdout);
Damien Miller7d6656c2000-05-20 15:22:36 +1000430 /* we don't have stderr for interactive terminal sessions, see below */
431 if (fderr != -1)
432 set_nonblock(fderr);
Damien Millerdcb6ecd2000-05-17 22:34:22 +1000433
Damien Miller95def091999-11-25 00:26:21 +1100434 connection_in = packet_get_connection_in();
435 connection_out = packet_get_connection_out();
436
437 previous_stdout_buffer_bytes = 0;
438
439 /* Set approximate I/O buffer size. */
440 if (packet_is_interactive())
441 buffer_high = 4096;
442 else
443 buffer_high = 64 * 1024;
444
445 /* Initialize max_fd to the maximum of the known file descriptors. */
446 max_fd = fdin;
447 if (fdout > max_fd)
448 max_fd = fdout;
449 if (fderr != -1 && fderr > max_fd)
450 max_fd = fderr;
451 if (connection_in > max_fd)
452 max_fd = connection_in;
453 if (connection_out > max_fd)
454 max_fd = connection_out;
455
456 /* Initialize Initialize buffers. */
457 buffer_init(&stdin_buffer);
458 buffer_init(&stdout_buffer);
459 buffer_init(&stderr_buffer);
460
Damien Miller5428f641999-11-25 11:54:57 +1100461 /*
462 * If we have no separate fderr (which is the case when we have a pty
463 * - there we cannot make difference between data sent to stdout and
464 * stderr), indicate that we have seen an EOF from stderr. This way
465 * we don\'t need to check the descriptor everywhere.
466 */
Damien Miller95def091999-11-25 00:26:21 +1100467 if (fderr == -1)
468 fderr_eof = 1;
469
Damien Millerb38eff82000-04-01 11:09:21 +1000470 server_init_dispatch();
471
Damien Miller95def091999-11-25 00:26:21 +1100472 /* Main loop of the server for the interactive session mode. */
473 for (;;) {
Damien Miller95def091999-11-25 00:26:21 +1100474
475 /* Process buffered packets from the client. */
476 process_buffered_input_packets();
477
Damien Miller5428f641999-11-25 11:54:57 +1100478 /*
479 * If we have received eof, and there is no more pending
480 * input data, cause a real eof by closing fdin.
481 */
Damien Miller95def091999-11-25 00:26:21 +1100482 if (stdin_eof && fdin != -1 && buffer_len(&stdin_buffer) == 0) {
483#ifdef USE_PIPES
484 close(fdin);
485#else
Damien Millerb38eff82000-04-01 11:09:21 +1000486 if (fdin != fdout)
Damien Miller95def091999-11-25 00:26:21 +1100487 close(fdin);
488 else
489 shutdown(fdin, SHUT_WR); /* We will no longer send. */
490#endif
491 fdin = -1;
492 }
Damien Miller5428f641999-11-25 11:54:57 +1100493 /* Make packets from buffered stderr data to send to the client. */
Damien Miller95def091999-11-25 00:26:21 +1100494 make_packets_from_stderr_data();
495
Damien Miller5428f641999-11-25 11:54:57 +1100496 /*
497 * Make packets from buffered stdout data to send to the
498 * client. If there is very little to send, this arranges to
499 * not send them now, but to wait a short while to see if we
500 * are getting more data. This is necessary, as some systems
501 * wake up readers from a pty after each separate character.
502 */
Damien Miller95def091999-11-25 00:26:21 +1100503 max_time_milliseconds = 0;
504 stdout_buffer_bytes = buffer_len(&stdout_buffer);
505 if (stdout_buffer_bytes != 0 && stdout_buffer_bytes < 256 &&
506 stdout_buffer_bytes != previous_stdout_buffer_bytes) {
507 /* try again after a while */
508 max_time_milliseconds = 10;
509 } else {
510 /* Send it now. */
511 make_packets_from_stdout_data();
512 }
513 previous_stdout_buffer_bytes = buffer_len(&stdout_buffer);
514
515 /* Send channel data to the client. */
516 if (packet_not_very_much_data_to_write())
517 channel_output_poll();
518
Damien Miller5428f641999-11-25 11:54:57 +1100519 /*
520 * Bail out of the loop if the program has closed its output
521 * descriptors, and we have no more data to send to the
522 * client, and there is no pending buffered data.
523 */
Damien Millerb284b542000-01-17 20:55:18 +1100524 if (((fdout_eof && fderr_eof) ||
525 (child_terminated && child_has_selected)) &&
526 !packet_have_data_to_write() &&
527 (buffer_len(&stdout_buffer) == 0) &&
528 (buffer_len(&stderr_buffer) == 0)) {
Damien Miller95def091999-11-25 00:26:21 +1100529 if (!channel_still_open())
Damien Millerb38eff82000-04-01 11:09:21 +1000530 break;
Damien Miller95def091999-11-25 00:26:21 +1100531 if (!waiting_termination) {
532 const char *s = "Waiting for forwarded connections to terminate...\r\n";
533 char *cp;
534 waiting_termination = 1;
535 buffer_append(&stderr_buffer, s, strlen(s));
536
537 /* Display list of open channels. */
538 cp = channel_open_message();
539 buffer_append(&stderr_buffer, cp, strlen(cp));
540 xfree(cp);
541 }
542 }
543 /* Sleep in select() until we can do something. */
544 wait_until_can_do_something(&readset, &writeset,
545 max_time_milliseconds);
546
547 /* Process any channel events. */
548 channel_after_select(&readset, &writeset);
549
550 /* Process input from the client and from program stdout/stderr. */
551 process_input(&readset);
552
553 /* Process output to the client and to program stdin. */
554 process_output(&writeset);
555 }
556
Damien Miller95def091999-11-25 00:26:21 +1100557 /* Cleanup and termination code. */
558
559 /* Wait until all output has been sent to the client. */
560 drain_output();
561
562 debug("End of interactive session; stdin %ld, stdout (read %ld, sent %ld), stderr %ld bytes.",
563 stdin_bytes, fdout_bytes, stdout_bytes, stderr_bytes);
564
565 /* Free and clear the buffers. */
566 buffer_free(&stdin_buffer);
567 buffer_free(&stdout_buffer);
568 buffer_free(&stderr_buffer);
569
570 /* Close the file descriptors. */
571 if (fdout != -1)
572 close(fdout);
573 fdout = -1;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000574 fdout_eof = 1;
Damien Miller95def091999-11-25 00:26:21 +1100575 if (fderr != -1)
576 close(fderr);
577 fderr = -1;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000578 fderr_eof = 1;
Damien Miller95def091999-11-25 00:26:21 +1100579 if (fdin != -1)
580 close(fdin);
581 fdin = -1;
582
583 /* Stop listening for channels; this removes unix domain sockets. */
584 channel_stop_listening();
585
586 /* Wait for the child to exit. Get its exit status. */
587 wait_pid = wait(&wait_status);
588 if (wait_pid < 0) {
589 /*
590 * It is possible that the wait was handled by SIGCHLD
591 * handler. This may result in either: this call
592 * returning with EINTR, or: this call returning ECHILD.
593 */
594 if (child_terminated)
595 wait_status = child_wait_status;
596 else
597 packet_disconnect("wait: %.100s", strerror(errno));
598 } else {
599 /* Check if it matches the process we forked. */
600 if (wait_pid != pid)
601 error("Strange, wait returned pid %d, expected %d",
Damien Milleraae6c611999-12-06 11:47:28 +1100602 wait_pid, pid);
Damien Miller95def091999-11-25 00:26:21 +1100603 }
604
605 /* We no longer want our SIGCHLD handler to be called. */
606 signal(SIGCHLD, SIG_DFL);
607
608 /* Check if it exited normally. */
609 if (WIFEXITED(wait_status)) {
610 /* Yes, normal exit. Get exit status and send it to the client. */
611 debug("Command exited with status %d.", WEXITSTATUS(wait_status));
612 packet_start(SSH_SMSG_EXITSTATUS);
613 packet_put_int(WEXITSTATUS(wait_status));
614 packet_send();
615 packet_write_wait();
616
Damien Miller5428f641999-11-25 11:54:57 +1100617 /*
618 * Wait for exit confirmation. Note that there might be
619 * other packets coming before it; however, the program has
620 * already died so we just ignore them. The client is
621 * supposed to respond with the confirmation when it receives
622 * the exit status.
623 */
Damien Miller95def091999-11-25 00:26:21 +1100624 do {
625 int plen;
626 type = packet_read(&plen);
627 }
628 while (type != SSH_CMSG_EXIT_CONFIRMATION);
629
630 debug("Received exit confirmation.");
631 return;
632 }
633 /* Check if the program terminated due to a signal. */
634 if (WIFSIGNALED(wait_status))
635 packet_disconnect("Command terminated on signal %d.",
636 WTERMSIG(wait_status));
637
638 /* Some weird exit cause. Just exit. */
639 packet_disconnect("wait returned status %04x.", wait_status);
640 /* NOTREACHED */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000641}
Damien Millerb38eff82000-04-01 11:09:21 +1000642
Damien Miller4af51302000-04-16 11:18:38 +1000643void
Damien Millerefb4afe2000-04-12 18:45:05 +1000644server_loop2(void)
645{
646 fd_set readset, writeset;
647 int had_channel = 0;
648 int status;
649 pid_t pid;
650
651 debug("Entering interactive session for SSH2.");
652
653 signal(SIGCHLD, sigchld_handler2);
Damien Millercf3888d2000-09-30 14:17:52 +1100654 signal(SIGPIPE, SIG_IGN);
Damien Millerefb4afe2000-04-12 18:45:05 +1000655 child_terminated = 0;
656 connection_in = packet_get_connection_in();
657 connection_out = packet_get_connection_out();
658 max_fd = connection_in;
659 if (connection_out > max_fd)
660 max_fd = connection_out;
661 server_init_dispatch();
662
663 for (;;) {
664 process_buffered_input_packets();
665 if (!had_channel && channel_still_open())
666 had_channel = 1;
667 if (had_channel && !channel_still_open()) {
668 debug("!channel_still_open.");
669 break;
670 }
671 if (packet_not_very_much_data_to_write())
672 channel_output_poll();
673 wait_until_can_do_something(&readset, &writeset, 0);
674 if (child_terminated) {
675 while ((pid = waitpid(-1, &status, WNOHANG)) > 0)
676 session_close_by_pid(pid, status);
677 child_terminated = 0;
Damien Millerfda78d92000-05-20 15:33:44 +1000678 signal(SIGCHLD, sigchld_handler2);
Damien Millerefb4afe2000-04-12 18:45:05 +1000679 }
680 channel_after_select(&readset, &writeset);
681 process_input(&readset);
682 process_output(&writeset);
683 }
684 signal(SIGCHLD, SIG_DFL);
685 while ((pid = waitpid(-1, &status, WNOHANG)) > 0)
686 session_close_by_pid(pid, status);
687 channel_stop_listening();
688}
689
Damien Millerb38eff82000-04-01 11:09:21 +1000690void
Damien Miller62cee002000-09-23 17:15:56 +1100691server_input_stdin_data(int type, int plen, void *ctxt)
Damien Millerb38eff82000-04-01 11:09:21 +1000692{
693 char *data;
694 unsigned int data_len;
695
696 /* Stdin data from the client. Append it to the buffer. */
697 /* Ignore any data if the client has closed stdin. */
698 if (fdin == -1)
699 return;
700 data = packet_get_string(&data_len);
701 packet_integrity_check(plen, (4 + data_len), type);
702 buffer_append(&stdin_buffer, data, data_len);
703 memset(data, 0, data_len);
704 xfree(data);
705}
706
707void
Damien Miller62cee002000-09-23 17:15:56 +1100708server_input_eof(int type, int plen, void *ctxt)
Damien Millerb38eff82000-04-01 11:09:21 +1000709{
710 /*
711 * Eof from the client. The stdin descriptor to the
712 * program will be closed when all buffered data has
713 * drained.
714 */
715 debug("EOF received for stdin.");
716 packet_integrity_check(plen, 0, type);
717 stdin_eof = 1;
718}
719
720void
Damien Miller62cee002000-09-23 17:15:56 +1100721server_input_window_size(int type, int plen, void *ctxt)
Damien Millerb38eff82000-04-01 11:09:21 +1000722{
723 int row = packet_get_int();
724 int col = packet_get_int();
725 int xpixel = packet_get_int();
726 int ypixel = packet_get_int();
727
728 debug("Window change received.");
729 packet_integrity_check(plen, 4 * 4, type);
730 if (fdin != -1)
731 pty_change_window_size(fdin, row, col, xpixel, ypixel);
732}
733
Damien Millerefb4afe2000-04-12 18:45:05 +1000734int
735input_direct_tcpip(void)
736{
737 int sock;
Damien Miller4af51302000-04-16 11:18:38 +1000738 char *target, *originator;
739 int target_port, originator_port;
Damien Millerefb4afe2000-04-12 18:45:05 +1000740
Damien Miller4af51302000-04-16 11:18:38 +1000741 target = packet_get_string(NULL);
742 target_port = packet_get_int();
Damien Millerefb4afe2000-04-12 18:45:05 +1000743 originator = packet_get_string(NULL);
744 originator_port = packet_get_int();
Damien Miller4af51302000-04-16 11:18:38 +1000745 packet_done();
Damien Millerb1715dc2000-05-30 13:44:51 +1000746
747 debug("open direct-tcpip: from %s port %d to %s port %d",
748 originator, originator_port, target, target_port);
Damien Millerf6d9e222000-06-18 14:50:44 +1000749
Damien Millerefb4afe2000-04-12 18:45:05 +1000750 /* XXX check permission */
Damien Miller37023962000-07-11 17:31:38 +1000751 if (no_port_forwarding_flag) {
Damien Millerf6d9e222000-06-18 14:50:44 +1000752 xfree(target);
753 xfree(originator);
754 return -1;
755 }
Damien Miller4af51302000-04-16 11:18:38 +1000756 sock = channel_connect_to(target, target_port);
757 xfree(target);
Damien Millerefb4afe2000-04-12 18:45:05 +1000758 xfree(originator);
759 if (sock < 0)
760 return -1;
761 return channel_new("direct-tcpip", SSH_CHANNEL_OPEN,
Damien Millere4340be2000-09-16 13:29:08 +1100762 sock, sock, -1, CHAN_TCP_WINDOW_DEFAULT,
763 CHAN_TCP_PACKET_DEFAULT, 0, xstrdup("direct-tcpip"));
Damien Millerefb4afe2000-04-12 18:45:05 +1000764}
765
Damien Miller4af51302000-04-16 11:18:38 +1000766void
Damien Miller62cee002000-09-23 17:15:56 +1100767server_input_channel_open(int type, int plen, void *ctxt)
Damien Millerefb4afe2000-04-12 18:45:05 +1000768{
769 Channel *c = NULL;
770 char *ctype;
771 int id;
772 unsigned int len;
773 int rchan;
774 int rmaxpack;
775 int rwindow;
776
777 ctype = packet_get_string(&len);
778 rchan = packet_get_int();
779 rwindow = packet_get_int();
780 rmaxpack = packet_get_int();
781
Damien Miller62cee002000-09-23 17:15:56 +1100782 debug("server_input_channel_open: ctype %s rchan %d win %d max %d",
Damien Millerefb4afe2000-04-12 18:45:05 +1000783 ctype, rchan, rwindow, rmaxpack);
784
785 if (strcmp(ctype, "session") == 0) {
786 debug("open session");
Damien Miller4af51302000-04-16 11:18:38 +1000787 packet_done();
Damien Millerefb4afe2000-04-12 18:45:05 +1000788 /*
789 * A server session has no fd to read or write
790 * until a CHANNEL_REQUEST for a shell is made,
791 * so we set the type to SSH_CHANNEL_LARVAL.
792 * Additionally, a callback for handling all
793 * CHANNEL_REQUEST messages is registered.
794 */
795 id = channel_new(ctype, SSH_CHANNEL_LARVAL,
Damien Millere4340be2000-09-16 13:29:08 +1100796 -1, -1, -1, 0, CHAN_SES_PACKET_DEFAULT,
797 0, xstrdup("server-session"));
Damien Millerefb4afe2000-04-12 18:45:05 +1000798 if (session_open(id) == 1) {
799 channel_register_callback(id, SSH2_MSG_CHANNEL_REQUEST,
800 session_input_channel_req, (void *)0);
801 channel_register_cleanup(id, session_close_by_channel);
802 c = channel_lookup(id);
803 } else {
804 debug("session open failed, free channel %d", id);
805 channel_free(id);
806 }
807 } else if (strcmp(ctype, "direct-tcpip") == 0) {
Damien Millerefb4afe2000-04-12 18:45:05 +1000808 id = input_direct_tcpip();
809 if (id >= 0)
810 c = channel_lookup(id);
811 }
812 if (c != NULL) {
813 debug("confirm %s", ctype);
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 {
825 debug("failure %s", ctype);
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
Damien Miller4af51302000-04-16 11:18:38 +1000836void
Damien Millerefb4afe2000-04-12 18:45:05 +1000837server_init_dispatch_20()
838{
839 debug("server_init_dispatch_20");
840 dispatch_init(&dispatch_protocol_error);
841 dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose);
842 dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data);
843 dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof);
844 dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data);
845 dispatch_set(SSH2_MSG_CHANNEL_OPEN, &server_input_channel_open);
846 dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
847 dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
848 dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &channel_input_channel_request);
849 dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust);
850}
Damien Miller4af51302000-04-16 11:18:38 +1000851void
Damien Millerb38eff82000-04-01 11:09:21 +1000852server_init_dispatch_13()
853{
854 debug("server_init_dispatch_13");
855 dispatch_init(NULL);
856 dispatch_set(SSH_CMSG_EOF, &server_input_eof);
857 dispatch_set(SSH_CMSG_STDIN_DATA, &server_input_stdin_data);
858 dispatch_set(SSH_CMSG_WINDOW_SIZE, &server_input_window_size);
859 dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close);
860 dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation);
861 dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data);
862 dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
863 dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
864 dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open);
865}
Damien Miller4af51302000-04-16 11:18:38 +1000866void
Damien Millerb38eff82000-04-01 11:09:21 +1000867server_init_dispatch_15()
868{
869 server_init_dispatch_13();
870 debug("server_init_dispatch_15");
871 dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof);
872 dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_oclose);
873}
Damien Miller4af51302000-04-16 11:18:38 +1000874void
Damien Millerb38eff82000-04-01 11:09:21 +1000875server_init_dispatch()
876{
Damien Millerefb4afe2000-04-12 18:45:05 +1000877 if (compat20)
878 server_init_dispatch_20();
879 else if (compat13)
Damien Millerb38eff82000-04-01 11:09:21 +1000880 server_init_dispatch_13();
881 else
882 server_init_dispatch_15();
883}