xref: /netbsd-src/crypto/external/bsd/openssh/dist/serverloop.c (revision fdd524d4ccd2bb0c6f67401e938dabf773eb0372)
1 /*	$NetBSD: serverloop.c,v 1.14 2016/03/11 01:55:00 christos Exp $	*/
2 /* $OpenBSD: serverloop.c,v 1.182 2016/02/08 10:57:07 djm Exp $ */
3 
4 /*
5  * Author: Tatu Ylonen <ylo@cs.hut.fi>
6  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
7  *                    All rights reserved
8  * Server main loop for handling the interactive session.
9  *
10  * As far as I am concerned, the code I have written for this software
11  * can be used freely for any purpose.  Any derived versions of this
12  * software must be clearly marked as such, and if the derived work is
13  * incompatible with the protocol description in the RFC file, it must be
14  * called by a name other than "ssh" or "Secure Shell".
15  *
16  * SSH2 support by Markus Friedl.
17  * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
18  *
19  * Redistribution and use in source and binary forms, with or without
20  * modification, are permitted provided that the following conditions
21  * are met:
22  * 1. Redistributions of source code must retain the above copyright
23  *    notice, this list of conditions and the following disclaimer.
24  * 2. Redistributions in binary form must reproduce the above copyright
25  *    notice, this list of conditions and the following disclaimer in the
26  *    documentation and/or other materials provided with the distribution.
27  *
28  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
29  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
30  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
31  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
32  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
33  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
34  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
35  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
36  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
37  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
38  */
39 
40 #include "includes.h"
41 __RCSID("$NetBSD: serverloop.c,v 1.14 2016/03/11 01:55:00 christos Exp $");
42 #include <sys/param.h>	/* MIN MAX */
43 #include <sys/types.h>
44 #include <sys/wait.h>
45 #include <sys/socket.h>
46 #include <sys/time.h>
47 #include <sys/queue.h>
48 
49 #include <netinet/in.h>
50 
51 #include <errno.h>
52 #include <fcntl.h>
53 #include <pwd.h>
54 #include <signal.h>
55 #include <string.h>
56 #include <termios.h>
57 #include <unistd.h>
58 #include <stdarg.h>
59 
60 #include "xmalloc.h"
61 #include "packet.h"
62 #include "buffer.h"
63 #include "log.h"
64 #include "misc.h"
65 #include "servconf.h"
66 #include "canohost.h"
67 #include "sshpty.h"
68 #include "channels.h"
69 #include "compat.h"
70 #include "ssh1.h"
71 #include "ssh2.h"
72 #include "key.h"
73 #include "cipher.h"
74 #include "kex.h"
75 #include "hostfile.h"
76 #include "auth.h"
77 #include "session.h"
78 #include "dispatch.h"
79 #include "auth-options.h"
80 #include "serverloop.h"
81 #include "ssherr.h"
82 
83 extern ServerOptions options;
84 
85 /* XXX */
86 extern Authctxt *the_authctxt;
87 extern int use_privsep;
88 
89 static Buffer stdin_buffer;	/* Buffer for stdin data. */
90 static Buffer stdout_buffer;	/* Buffer for stdout data. */
91 static Buffer stderr_buffer;	/* Buffer for stderr data. */
92 static int fdin;		/* Descriptor for stdin (for writing) */
93 static int fdout;		/* Descriptor for stdout (for reading);
94 				   May be same number as fdin. */
95 static int fderr;		/* Descriptor for stderr.  May be -1. */
96 static u_long stdin_bytes = 0;	/* Number of bytes written to stdin. */
97 static u_long stdout_bytes = 0;	/* Number of stdout bytes sent to client. */
98 static u_long stderr_bytes = 0;	/* Number of stderr bytes sent to client. */
99 static u_long fdout_bytes = 0;	/* Number of stdout bytes read from program. */
100 static int stdin_eof = 0;	/* EOF message received from client. */
101 static int fdout_eof = 0;	/* EOF encountered reading from fdout. */
102 static int fderr_eof = 0;	/* EOF encountered readung from fderr. */
103 static int fdin_is_tty = 0;	/* fdin points to a tty. */
104 static int connection_in;	/* Connection to client (input). */
105 static int connection_out;	/* Connection to client (output). */
106 static int connection_closed = 0;	/* Connection to client closed. */
107 static u_int buffer_high;	/* "Soft" max buffer size. */
108 static int no_more_sessions = 0; /* Disallow further sessions. */
109 
110 /*
111  * This SIGCHLD kludge is used to detect when the child exits.  The server
112  * will exit after that, as soon as forwarded connections have terminated.
113  */
114 
115 static volatile sig_atomic_t child_terminated = 0;	/* The child has terminated. */
116 
117 /* Cleanup on signals (!use_privsep case only) */
118 static volatile sig_atomic_t received_sigterm = 0;
119 
120 /* prototypes */
121 static void server_init_dispatch(void);
122 
123 /*
124  * Returns current time in seconds from Jan 1, 1970 with the maximum
125  * available resolution.
126  */
127 
128 static double
129 get_current_time(void)
130 {
131 	struct timeval tv;
132 	gettimeofday(&tv, NULL);
133 	return (double) tv.tv_sec + (double) tv.tv_usec / 1000000.0;
134 }
135 
136 /*
137  * we write to this pipe if a SIGCHLD is caught in order to avoid
138  * the race between select() and child_terminated
139  */
140 static int notify_pipe[2];
141 static void
142 notify_setup(void)
143 {
144 	if (pipe(notify_pipe) < 0) {
145 		error("pipe(notify_pipe) failed %s", strerror(errno));
146 	} else if ((fcntl(notify_pipe[0], F_SETFD, FD_CLOEXEC) == -1) ||
147 	    (fcntl(notify_pipe[1], F_SETFD, FD_CLOEXEC) == -1)) {
148 		error("fcntl(notify_pipe, F_SETFD) failed %s", strerror(errno));
149 		close(notify_pipe[0]);
150 		close(notify_pipe[1]);
151 	} else {
152 		set_nonblock(notify_pipe[0]);
153 		set_nonblock(notify_pipe[1]);
154 		return;
155 	}
156 	notify_pipe[0] = -1;	/* read end */
157 	notify_pipe[1] = -1;	/* write end */
158 }
159 static void
160 notify_parent(void)
161 {
162 	if (notify_pipe[1] != -1)
163 		(void)write(notify_pipe[1], "", 1);
164 }
165 static void
166 notify_prepare(fd_set *readset)
167 {
168 	if (notify_pipe[0] != -1)
169 		FD_SET(notify_pipe[0], readset);
170 }
171 static void
172 notify_done(fd_set *readset)
173 {
174 	char c;
175 
176 	if (notify_pipe[0] != -1 && FD_ISSET(notify_pipe[0], readset))
177 		while (read(notify_pipe[0], &c, 1) != -1)
178 			debug2("notify_done: reading");
179 }
180 
181 /*ARGSUSED*/
182 static void
183 sigchld_handler(int sig)
184 {
185 	int save_errno = errno;
186 	child_terminated = 1;
187 	signal(SIGCHLD, sigchld_handler);
188 	notify_parent();
189 	errno = save_errno;
190 }
191 
192 /*ARGSUSED*/
193 static void
194 sigterm_handler(int sig)
195 {
196 	received_sigterm = sig;
197 }
198 
199 /*
200  * Make packets from buffered stderr data, and buffer it for sending
201  * to the client.
202  */
203 static void
204 make_packets_from_stderr_data(void)
205 {
206 	u_int len;
207 
208 	/* Send buffered stderr data to the client. */
209 	while (buffer_len(&stderr_buffer) > 0 &&
210 	    packet_not_very_much_data_to_write()) {
211 		len = buffer_len(&stderr_buffer);
212 		if (packet_is_interactive()) {
213 			if (len > 512)
214 				len = 512;
215 		} else {
216 			/* Keep the packets at reasonable size. */
217 			if (len > packet_get_maxsize())
218 				len = packet_get_maxsize();
219 		}
220 		packet_start(SSH_SMSG_STDERR_DATA);
221 		packet_put_string(buffer_ptr(&stderr_buffer), len);
222 		packet_send();
223 		buffer_consume(&stderr_buffer, len);
224 		stderr_bytes += len;
225 	}
226 }
227 
228 /*
229  * Make packets from buffered stdout data, and buffer it for sending to the
230  * client.
231  */
232 static void
233 make_packets_from_stdout_data(void)
234 {
235 	u_int len;
236 
237 	/* Send buffered stdout data to the client. */
238 	while (buffer_len(&stdout_buffer) > 0 &&
239 	    packet_not_very_much_data_to_write()) {
240 		len = buffer_len(&stdout_buffer);
241 		if (packet_is_interactive()) {
242 			if (len > 512)
243 				len = 512;
244 		} else {
245 			/* Keep the packets at reasonable size. */
246 			if (len > packet_get_maxsize())
247 				len = packet_get_maxsize();
248 		}
249 		packet_start(SSH_SMSG_STDOUT_DATA);
250 		packet_put_string(buffer_ptr(&stdout_buffer), len);
251 		packet_send();
252 		buffer_consume(&stdout_buffer, len);
253 		stdout_bytes += len;
254 	}
255 }
256 
257 static void
258 client_alive_check(void)
259 {
260 	int channel_id;
261 
262 	/* timeout, check to see how many we have had */
263 	if (packet_inc_alive_timeouts() > options.client_alive_count_max) {
264 		logit("Timeout, client not responding.");
265 		cleanup_exit(255);
266 	}
267 
268 	/*
269 	 * send a bogus global/channel request with "wantreply",
270 	 * we should get back a failure
271 	 */
272 	if ((channel_id = channel_find_open()) == -1) {
273 		packet_start(SSH2_MSG_GLOBAL_REQUEST);
274 		packet_put_cstring("keepalive@openssh.com");
275 		packet_put_char(1);	/* boolean: want reply */
276 	} else {
277 		channel_request_start(channel_id, "keepalive@openssh.com", 1);
278 	}
279 	packet_send();
280 }
281 
282 /*
283  * Sleep in select() until we can do something.  This will initialize the
284  * select masks.  Upon return, the masks will indicate which descriptors
285  * have data or can accept data.  Optionally, a maximum time can be specified
286  * for the duration of the wait (0 = infinite).
287  */
288 static void
289 wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
290     u_int *nallocp, u_int64_t max_time_milliseconds)
291 {
292 	struct timeval tv, *tvp;
293 	int ret;
294 	time_t minwait_secs = 0;
295 	int client_alive_scheduled = 0;
296 
297 	/* Allocate and update select() masks for channel descriptors. */
298 	channel_prepare_select(readsetp, writesetp, maxfdp, nallocp,
299 	    &minwait_secs, 0);
300 
301 	if (minwait_secs != 0)
302 		max_time_milliseconds = MIN(max_time_milliseconds,
303 		    (u_int)minwait_secs * 1000);
304 
305 	/*
306 	 * if using client_alive, set the max timeout accordingly,
307 	 * and indicate that this particular timeout was for client
308 	 * alive by setting the client_alive_scheduled flag.
309 	 *
310 	 * this could be randomized somewhat to make traffic
311 	 * analysis more difficult, but we're not doing it yet.
312 	 */
313 	if (compat20 &&
314 	    max_time_milliseconds == 0 && options.client_alive_interval) {
315 		client_alive_scheduled = 1;
316 		max_time_milliseconds =
317 		    (u_int64_t)options.client_alive_interval * 1000;
318 	}
319 
320 	if (compat20) {
321 #if 0
322 		/* wrong: bad condition XXX */
323 		if (channel_not_very_much_buffered_data())
324 #endif
325 		FD_SET(connection_in, *readsetp);
326 	} else {
327 		/*
328 		 * Read packets from the client unless we have too much
329 		 * buffered stdin or channel data.
330 		 */
331 		if (buffer_len(&stdin_buffer) < buffer_high &&
332 		    channel_not_very_much_buffered_data())
333 			FD_SET(connection_in, *readsetp);
334 		/*
335 		 * If there is not too much data already buffered going to
336 		 * the client, try to get some more data from the program.
337 		 */
338 		if (packet_not_very_much_data_to_write()) {
339 			if (!fdout_eof)
340 				FD_SET(fdout, *readsetp);
341 			if (!fderr_eof)
342 				FD_SET(fderr, *readsetp);
343 		}
344 		/*
345 		 * If we have buffered data, try to write some of that data
346 		 * to the program.
347 		 */
348 		if (fdin != -1 && buffer_len(&stdin_buffer) > 0)
349 			FD_SET(fdin, *writesetp);
350 	}
351 	notify_prepare(*readsetp);
352 
353 	/*
354 	 * If we have buffered packet data going to the client, mark that
355 	 * descriptor.
356 	 */
357 	if (packet_have_data_to_write())
358 		FD_SET(connection_out, *writesetp);
359 
360 	/*
361 	 * If child has terminated and there is enough buffer space to read
362 	 * from it, then read as much as is available and exit.
363 	 */
364 	if (child_terminated && packet_not_very_much_data_to_write())
365 		if (max_time_milliseconds == 0 || client_alive_scheduled)
366 			max_time_milliseconds = 100;
367 
368 	if (max_time_milliseconds == 0)
369 		tvp = NULL;
370 	else {
371 		tv.tv_sec = max_time_milliseconds / 1000;
372 		tv.tv_usec = 1000 * (max_time_milliseconds % 1000);
373 		tvp = &tv;
374 	}
375 
376 	/* Wait for something to happen, or the timeout to expire. */
377 	ret = select((*maxfdp)+1, *readsetp, *writesetp, NULL, tvp);
378 
379 	if (ret == -1) {
380 		memset(*readsetp, 0, *nallocp);
381 		memset(*writesetp, 0, *nallocp);
382 		if (errno != EINTR)
383 			error("select: %.100s", strerror(errno));
384 	} else if (ret == 0 && client_alive_scheduled)
385 		client_alive_check();
386 
387 	notify_done(*readsetp);
388 }
389 
390 /*
391  * Processes input from the client and the program.  Input data is stored
392  * in buffers and processed later.
393  */
394 static void
395 process_input(fd_set *readset)
396 {
397 	int len;
398 	char buf[16384];
399 
400 	/* Read and buffer any input data from the client. */
401 	if (FD_ISSET(connection_in, readset)) {
402 		len = read(connection_in, buf, sizeof(buf));
403 		if (len == 0) {
404 			verbose("Connection closed by %.100s",
405 			    get_remote_ipaddr());
406 			connection_closed = 1;
407 			if (compat20)
408 				return;
409 			cleanup_exit(255);
410 		} else if (len < 0) {
411 			if (errno != EINTR && errno != EAGAIN) {
412 				verbose("Read error from remote host "
413 				    "%.100s: %.100s",
414 				    get_remote_ipaddr(), strerror(errno));
415 				cleanup_exit(255);
416 			}
417 		} else {
418 			/* Buffer any received data. */
419 			packet_process_incoming(buf, len);
420 			fdout_bytes += len;
421 		}
422 	}
423 	if (compat20)
424 		return;
425 
426 	/* Read and buffer any available stdout data from the program. */
427 	if (!fdout_eof && FD_ISSET(fdout, readset)) {
428 		len = read(fdout, buf, sizeof(buf));
429 		if (len < 0 && (errno == EINTR || errno == EAGAIN)) {
430 			/* do nothing */
431 		} else if (len <= 0) {
432 			fdout_eof = 1;
433 		} else {
434 			buffer_append(&stdout_buffer, buf, len);
435 			debug ("FD out now: %ld", fdout_bytes);
436 			fdout_bytes += len;
437 		}
438 	}
439 	/* Read and buffer any available stderr data from the program. */
440 	if (!fderr_eof && FD_ISSET(fderr, readset)) {
441 		len = read(fderr, buf, sizeof(buf));
442 		if (len < 0 && (errno == EINTR || errno == EAGAIN)) {
443 			/* do nothing */
444 		} else if (len <= 0) {
445 			fderr_eof = 1;
446 		} else {
447 			buffer_append(&stderr_buffer, buf, len);
448 		}
449 	}
450 }
451 
452 /*
453  * Sends data from internal buffers to client program stdin.
454  */
455 static void
456 process_output(fd_set *writeset)
457 {
458 	struct termios tio;
459 	u_char *data;
460 	u_int dlen;
461 	int len;
462 
463 	/* Write buffered data to program stdin. */
464 	if (!compat20 && fdin != -1 && FD_ISSET(fdin, writeset)) {
465 		data = buffer_ptr(&stdin_buffer);
466 		dlen = buffer_len(&stdin_buffer);
467 		len = write(fdin, data, dlen);
468 		if (len < 0 && (errno == EINTR || errno == EAGAIN)) {
469 			/* do nothing */
470 		} else if (len <= 0) {
471 			if (fdin != fdout)
472 				close(fdin);
473 			else
474 				shutdown(fdin, SHUT_WR); /* We will no longer send. */
475 			fdin = -1;
476 		} else {
477 			/* Successful write. */
478 			if (fdin_is_tty && dlen >= 1 && data[0] != '\r' &&
479 			    tcgetattr(fdin, &tio) == 0 &&
480 			    !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
481 				/*
482 				 * Simulate echo to reduce the impact of
483 				 * traffic analysis
484 				 */
485 				packet_send_ignore(len);
486 				packet_send();
487 			}
488 			/* Consume the data from the buffer. */
489 			buffer_consume(&stdin_buffer, len);
490 			/* Update the count of bytes written to the program. */
491 			stdin_bytes += len;
492 		}
493 	}
494 	/* Send any buffered packet data to the client. */
495 	if (FD_ISSET(connection_out, writeset))
496 		stdin_bytes += packet_write_poll();
497 }
498 
499 /*
500  * Wait until all buffered output has been sent to the client.
501  * This is used when the program terminates.
502  */
503 static void
504 drain_output(void)
505 {
506 	/* Send any buffered stdout data to the client. */
507 	if (buffer_len(&stdout_buffer) > 0) {
508 		packet_start(SSH_SMSG_STDOUT_DATA);
509 		packet_put_string(buffer_ptr(&stdout_buffer),
510 				  buffer_len(&stdout_buffer));
511 		packet_send();
512 		/* Update the count of sent bytes. */
513 		stdout_bytes += buffer_len(&stdout_buffer);
514 	}
515 	/* Send any buffered stderr data to the client. */
516 	if (buffer_len(&stderr_buffer) > 0) {
517 		packet_start(SSH_SMSG_STDERR_DATA);
518 		packet_put_string(buffer_ptr(&stderr_buffer),
519 				  buffer_len(&stderr_buffer));
520 		packet_send();
521 		/* Update the count of sent bytes. */
522 		stderr_bytes += buffer_len(&stderr_buffer);
523 	}
524 	/* Wait until all buffered data has been written to the client. */
525 	packet_write_wait();
526 }
527 
528 static void
529 process_buffered_input_packets(void)
530 {
531 	dispatch_run(DISPATCH_NONBLOCK, NULL, active_state);
532 }
533 
534 /*
535  * Performs the interactive session.  This handles data transmission between
536  * the client and the program.  Note that the notion of stdin, stdout, and
537  * stderr in this function is sort of reversed: this function writes to
538  * stdin (of the child program), and reads from stdout and stderr (of the
539  * child program).
540  */
541 void
542 server_loop(pid_t pid, int fdin_arg, int fdout_arg, int fderr_arg)
543 {
544 	fd_set *readset = NULL, *writeset = NULL;
545 	int max_fd = 0;
546 	u_int nalloc = 0;
547 	int wait_status;	/* Status returned by wait(). */
548 	pid_t wait_pid;		/* pid returned by wait(). */
549 	int waiting_termination = 0;	/* Have displayed waiting close message. */
550 	u_int64_t max_time_milliseconds;
551 	u_int previous_stdout_buffer_bytes;
552 	u_int stdout_buffer_bytes;
553 	int type;
554 
555 	debug("Entering interactive session.");
556 
557 	/* Initialize the SIGCHLD kludge. */
558 	child_terminated = 0;
559 	signal(SIGCHLD, sigchld_handler);
560 
561 	if (!use_privsep) {
562 		signal(SIGTERM, sigterm_handler);
563 		signal(SIGINT, sigterm_handler);
564 		signal(SIGQUIT, sigterm_handler);
565 	}
566 
567 	/* Initialize our global variables. */
568 	fdin = fdin_arg;
569 	fdout = fdout_arg;
570 	fderr = fderr_arg;
571 
572 	/* nonblocking IO */
573 	set_nonblock(fdin);
574 	set_nonblock(fdout);
575 	/* we don't have stderr for interactive terminal sessions, see below */
576 	if (fderr != -1)
577 		set_nonblock(fderr);
578 
579 	if (!(datafellows & SSH_BUG_IGNOREMSG) && isatty(fdin))
580 		fdin_is_tty = 1;
581 
582 	connection_in = packet_get_connection_in();
583 	connection_out = packet_get_connection_out();
584 
585 	notify_setup();
586 
587 	previous_stdout_buffer_bytes = 0;
588 
589 	/* Set approximate I/O buffer size. */
590 	if (packet_is_interactive())
591 		buffer_high = 4096;
592 	else
593 		buffer_high = 64 * 1024;
594 
595 #if 0
596 	/* Initialize max_fd to the maximum of the known file descriptors. */
597 	max_fd = MAX(connection_in, connection_out);
598 	max_fd = MAX(max_fd, fdin);
599 	max_fd = MAX(max_fd, fdout);
600 	if (fderr != -1)
601 		max_fd = MAX(max_fd, fderr);
602 #endif
603 
604 	/* Initialize Initialize buffers. */
605 	buffer_init(&stdin_buffer);
606 	buffer_init(&stdout_buffer);
607 	buffer_init(&stderr_buffer);
608 
609 	/*
610 	 * If we have no separate fderr (which is the case when we have a pty
611 	 * - there we cannot make difference between data sent to stdout and
612 	 * stderr), indicate that we have seen an EOF from stderr.  This way
613 	 * we don't need to check the descriptor everywhere.
614 	 */
615 	if (fderr == -1)
616 		fderr_eof = 1;
617 
618 	server_init_dispatch();
619 
620 	/* Main loop of the server for the interactive session mode. */
621 	for (;;) {
622 
623 		/* Process buffered packets from the client. */
624 		process_buffered_input_packets();
625 
626 		/*
627 		 * If we have received eof, and there is no more pending
628 		 * input data, cause a real eof by closing fdin.
629 		 */
630 		if (stdin_eof && fdin != -1 && buffer_len(&stdin_buffer) == 0) {
631 			if (fdin != fdout)
632 				close(fdin);
633 			else
634 				shutdown(fdin, SHUT_WR); /* We will no longer send. */
635 			fdin = -1;
636 		}
637 		/* Make packets from buffered stderr data to send to the client. */
638 		make_packets_from_stderr_data();
639 
640 		/*
641 		 * Make packets from buffered stdout data to send to the
642 		 * client. If there is very little to send, this arranges to
643 		 * not send them now, but to wait a short while to see if we
644 		 * are getting more data. This is necessary, as some systems
645 		 * wake up readers from a pty after each separate character.
646 		 */
647 		max_time_milliseconds = 0;
648 		stdout_buffer_bytes = buffer_len(&stdout_buffer);
649 		if (stdout_buffer_bytes != 0 && stdout_buffer_bytes < 256 &&
650 		    stdout_buffer_bytes != previous_stdout_buffer_bytes) {
651 			/* try again after a while */
652 			max_time_milliseconds = 10;
653 		} else {
654 			/* Send it now. */
655 			make_packets_from_stdout_data();
656 		}
657 		previous_stdout_buffer_bytes = buffer_len(&stdout_buffer);
658 
659 		/* Send channel data to the client. */
660 		if (packet_not_very_much_data_to_write())
661 			channel_output_poll();
662 
663 		/*
664 		 * Bail out of the loop if the program has closed its output
665 		 * descriptors, and we have no more data to send to the
666 		 * client, and there is no pending buffered data.
667 		 */
668 		if (fdout_eof && fderr_eof && !packet_have_data_to_write() &&
669 		    buffer_len(&stdout_buffer) == 0 && buffer_len(&stderr_buffer) == 0) {
670 			if (!channel_still_open())
671 				break;
672 			if (!waiting_termination) {
673 				const char *s = "Waiting for forwarded connections to terminate...\r\n";
674 				char *cp;
675 				waiting_termination = 1;
676 				buffer_append(&stderr_buffer, s, strlen(s));
677 
678 				/* Display list of open channels. */
679 				cp = channel_open_message();
680 				buffer_append(&stderr_buffer, cp, strlen(cp));
681 				free(cp);
682 			}
683 		}
684 		max_fd = MAX(connection_in, connection_out);
685 		max_fd = MAX(max_fd, fdin);
686 		max_fd = MAX(max_fd, fdout);
687 		max_fd = MAX(max_fd, fderr);
688 		max_fd = MAX(max_fd, notify_pipe[0]);
689 
690 		/* Sleep in select() until we can do something. */
691 		wait_until_can_do_something(&readset, &writeset, &max_fd,
692 		    &nalloc, max_time_milliseconds);
693 
694 		if (received_sigterm) {
695 			logit("Exiting on signal %d", (int)received_sigterm);
696 			/* Clean up sessions, utmp, etc. */
697 			cleanup_exit(255);
698 		}
699 
700 		/* Process any channel events. */
701 		channel_after_select(readset, writeset);
702 
703 		/* Process input from the client and from program stdout/stderr. */
704 		process_input(readset);
705 
706 		/* Process output to the client and to program stdin. */
707 		process_output(writeset);
708 	}
709 	free(readset);
710 	free(writeset);
711 
712 	/* Cleanup and termination code. */
713 
714 	/* Wait until all output has been sent to the client. */
715 	drain_output();
716 
717 	debug("End of interactive session; stdin %ld, stdout (read %ld, sent %ld), stderr %ld bytes.",
718 	    stdin_bytes, fdout_bytes, stdout_bytes, stderr_bytes);
719 
720 	/* Free and clear the buffers. */
721 	buffer_free(&stdin_buffer);
722 	buffer_free(&stdout_buffer);
723 	buffer_free(&stderr_buffer);
724 
725 	/* Close the file descriptors. */
726 	if (fdout != -1)
727 		close(fdout);
728 	fdout = -1;
729 	fdout_eof = 1;
730 	if (fderr != -1)
731 		close(fderr);
732 	fderr = -1;
733 	fderr_eof = 1;
734 	if (fdin != -1)
735 		close(fdin);
736 	fdin = -1;
737 
738 	channel_free_all();
739 
740 	/* We no longer want our SIGCHLD handler to be called. */
741 	signal(SIGCHLD, SIG_DFL);
742 
743 	while ((wait_pid = waitpid(-1, &wait_status, 0)) < 0)
744 		if (errno != EINTR)
745 			packet_disconnect("wait: %.100s", strerror(errno));
746 	if (wait_pid != pid)
747 		error("Strange, wait returned pid %ld, expected %ld",
748 		    (long)wait_pid, (long)pid);
749 
750 	/* Check if it exited normally. */
751 	if (WIFEXITED(wait_status)) {
752 		/* Yes, normal exit.  Get exit status and send it to the client. */
753 		debug("Command exited with status %d.", WEXITSTATUS(wait_status));
754 		packet_start(SSH_SMSG_EXITSTATUS);
755 		packet_put_int(WEXITSTATUS(wait_status));
756 		packet_send();
757 		packet_write_wait();
758 
759 		/*
760 		 * Wait for exit confirmation.  Note that there might be
761 		 * other packets coming before it; however, the program has
762 		 * already died so we just ignore them.  The client is
763 		 * supposed to respond with the confirmation when it receives
764 		 * the exit status.
765 		 */
766 		do {
767 			type = packet_read();
768 		}
769 		while (type != SSH_CMSG_EXIT_CONFIRMATION);
770 
771 		debug("Received exit confirmation.");
772 		return;
773 	}
774 	/* Check if the program terminated due to a signal. */
775 	if (WIFSIGNALED(wait_status))
776 		packet_disconnect("Command terminated on signal %d.",
777 				  WTERMSIG(wait_status));
778 
779 	/* Some weird exit cause.  Just exit. */
780 	packet_disconnect("wait returned status %04x.", wait_status);
781 	/* NOTREACHED */
782 }
783 
784 static void
785 collect_children(void)
786 {
787 	pid_t pid;
788 	sigset_t oset, nset;
789 	int status;
790 
791 	/* block SIGCHLD while we check for dead children */
792 	sigemptyset(&nset);
793 	sigaddset(&nset, SIGCHLD);
794 	sigprocmask(SIG_BLOCK, &nset, &oset);
795 	if (child_terminated) {
796 		debug("Received SIGCHLD.");
797 		while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
798 		    (pid < 0 && errno == EINTR))
799 			if (pid > 0)
800 				session_close_by_pid(pid, status);
801 		child_terminated = 0;
802 	}
803 	sigprocmask(SIG_SETMASK, &oset, NULL);
804 }
805 
806 void
807 server_loop2(Authctxt *authctxt)
808 {
809 	fd_set *readset = NULL, *writeset = NULL;
810 	int max_fd;
811 	u_int nalloc = 0;
812 	u_int64_t rekey_timeout_ms = 0;
813 	double start_time, total_time;
814 
815 	debug("Entering interactive session for SSH2.");
816 	start_time = get_current_time();
817 
818 	signal(SIGCHLD, sigchld_handler);
819 	child_terminated = 0;
820 	connection_in = packet_get_connection_in();
821 	connection_out = packet_get_connection_out();
822 
823 	if (!use_privsep) {
824 		signal(SIGTERM, sigterm_handler);
825 		signal(SIGINT, sigterm_handler);
826 		signal(SIGQUIT, sigterm_handler);
827 	}
828 
829 	notify_setup();
830 
831 	max_fd = MAX(connection_in, connection_out);
832 	max_fd = MAX(max_fd, notify_pipe[0]);
833 
834 	server_init_dispatch();
835 
836 	for (;;) {
837 		process_buffered_input_packets();
838 
839 		if (!ssh_packet_is_rekeying(active_state) &&
840 		    packet_not_very_much_data_to_write())
841 			channel_output_poll();
842 		if (options.rekey_interval > 0 && compat20 &&
843 		    !ssh_packet_is_rekeying(active_state))
844 			rekey_timeout_ms = packet_get_rekey_timeout() * 1000;
845 		else
846 			rekey_timeout_ms = 0;
847 
848 		wait_until_can_do_something(&readset, &writeset, &max_fd,
849 		    &nalloc, rekey_timeout_ms);
850 
851 		if (received_sigterm) {
852 			logit("Exiting on signal %d", (int)received_sigterm);
853 			/* Clean up sessions, utmp, etc. */
854 			cleanup_exit(255);
855 		}
856 
857 		collect_children();
858 		if (!ssh_packet_is_rekeying(active_state))
859 			channel_after_select(readset, writeset);
860 		process_input(readset);
861 		if (connection_closed)
862 			break;
863 		process_output(writeset);
864 	}
865 	collect_children();
866 
867 	free(readset);
868 	free(writeset);
869 
870 	/* free all channels, no more reads and writes */
871 	channel_free_all();
872 
873 	/* free remaining sessions, e.g. remove wtmp entries */
874 	session_destroy_all(NULL);
875 	total_time = get_current_time() - start_time;
876 	logit("SSH: Server;LType: Throughput;Remote: %s-%d;IN: %lu;OUT: %lu;Duration: %.1f;tPut_in: %.1f;tPut_out: %.1f",
877 	      get_remote_ipaddr(), get_remote_port(),
878 	      stdin_bytes, fdout_bytes, total_time, stdin_bytes / total_time,
879 	      fdout_bytes / total_time);
880 }
881 
882 static int
883 server_input_keep_alive(int type, u_int32_t seq, void *ctxt)
884 {
885 	debug("Got %d/%u for keepalive", type, seq);
886 	/*
887 	 * reset timeout, since we got a sane answer from the client.
888 	 * even if this was generated by something other than
889 	 * the bogus CHANNEL_REQUEST we send for keepalives.
890 	 */
891 	packet_set_alive_timeouts(0);
892 	return 0;
893 }
894 
895 static int
896 server_input_stdin_data(int type, u_int32_t seq, void *ctxt)
897 {
898 	char *data;
899 	u_int data_len;
900 
901 	/* Stdin data from the client.  Append it to the buffer. */
902 	/* Ignore any data if the client has closed stdin. */
903 	if (fdin == -1)
904 		return 0;
905 	data = packet_get_string(&data_len);
906 	packet_check_eom();
907 	buffer_append(&stdin_buffer, data, data_len);
908 	explicit_bzero(data, data_len);
909 	free(data);
910 	return 0;
911 }
912 
913 static int
914 server_input_eof(int type, u_int32_t seq, void *ctxt)
915 {
916 	/*
917 	 * Eof from the client.  The stdin descriptor to the
918 	 * program will be closed when all buffered data has
919 	 * drained.
920 	 */
921 	debug("EOF received for stdin.");
922 	packet_check_eom();
923 	stdin_eof = 1;
924 	return 0;
925 }
926 
927 static int
928 server_input_window_size(int type, u_int32_t seq, void *ctxt)
929 {
930 	u_int row = packet_get_int();
931 	u_int col = packet_get_int();
932 	u_int xpixel = packet_get_int();
933 	u_int ypixel = packet_get_int();
934 
935 	debug("Window change received.");
936 	packet_check_eom();
937 	if (fdin != -1)
938 		pty_change_window_size(fdin, row, col, xpixel, ypixel);
939 	return 0;
940 }
941 
942 static Channel *
943 server_request_direct_tcpip(void)
944 {
945 	Channel *c = NULL;
946 	char *target, *originator;
947 	u_short target_port, originator_port;
948 
949 	target = packet_get_string(NULL);
950 	target_port = packet_get_int();
951 	originator = packet_get_string(NULL);
952 	originator_port = packet_get_int();
953 	packet_check_eom();
954 
955 	debug("server_request_direct_tcpip: originator %s port %d, target %s "
956 	    "port %d", originator, originator_port, target, target_port);
957 
958 	/* XXX fine grained permissions */
959 	if ((options.allow_tcp_forwarding & FORWARD_LOCAL) != 0 &&
960 	    !no_port_forwarding_flag) {
961 		c = channel_connect_to_port(target, target_port,
962 		    "direct-tcpip", "direct-tcpip");
963 	} else {
964 		logit("refused local port forward: "
965 		    "originator %s port %d, target %s port %d",
966 		    originator, originator_port, target, target_port);
967 	}
968 
969 	free(originator);
970 	free(target);
971 
972 	return c;
973 }
974 
975 static Channel *
976 server_request_direct_streamlocal(void)
977 {
978 	Channel *c = NULL;
979 	char *target, *originator;
980 	u_short originator_port;
981 
982 	target = packet_get_string(NULL);
983 	originator = packet_get_string(NULL);
984 	originator_port = packet_get_int();
985 	packet_check_eom();
986 
987 	debug("server_request_direct_streamlocal: originator %s port %d, target %s",
988 	    originator, originator_port, target);
989 
990 	/* XXX fine grained permissions */
991 	if ((options.allow_streamlocal_forwarding & FORWARD_LOCAL) != 0 &&
992 	    !no_port_forwarding_flag) {
993 		c = channel_connect_to_path(target,
994 		    "direct-streamlocal@openssh.com", "direct-streamlocal");
995 	} else {
996 		logit("refused streamlocal port forward: "
997 		    "originator %s port %d, target %s",
998 		    originator, originator_port, target);
999 	}
1000 
1001 	free(originator);
1002 	free(target);
1003 
1004 	return c;
1005 }
1006 
1007 static Channel *
1008 server_request_tun(void)
1009 {
1010 	Channel *c = NULL;
1011 	int mode, tun;
1012 	int sock;
1013 
1014 	mode = packet_get_int();
1015 	switch (mode) {
1016 	case SSH_TUNMODE_POINTOPOINT:
1017 	case SSH_TUNMODE_ETHERNET:
1018 		break;
1019 	default:
1020 		packet_send_debug("Unsupported tunnel device mode.");
1021 		return NULL;
1022 	}
1023 	if ((options.permit_tun & mode) == 0) {
1024 		packet_send_debug("Server has rejected tunnel device "
1025 		    "forwarding");
1026 		return NULL;
1027 	}
1028 
1029 	tun = packet_get_int();
1030 	if (forced_tun_device != -1) {
1031 		if (tun != SSH_TUNID_ANY && forced_tun_device != tun)
1032 			goto done;
1033 		tun = forced_tun_device;
1034 	}
1035 	sock = tun_open(tun, mode);
1036 	if (sock < 0)
1037 		goto done;
1038 	if (options.hpn_disabled)
1039 	c = channel_new("tun", SSH_CHANNEL_OPEN, sock, sock, -1,
1040 	    CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1);
1041 	else
1042 		c = channel_new("tun", SSH_CHANNEL_OPEN, sock, sock, -1,
1043 		    options.hpn_buffer_size, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1);
1044 	c->datagram = 1;
1045 
1046  done:
1047 	if (c == NULL)
1048 		packet_send_debug("Failed to open the tunnel device.");
1049 	return c;
1050 }
1051 
1052 static Channel *
1053 server_request_session(void)
1054 {
1055 	Channel *c;
1056 
1057 	debug("input_session_request");
1058 	packet_check_eom();
1059 
1060 	if (no_more_sessions) {
1061 		packet_disconnect("Possible attack: attempt to open a session "
1062 		    "after additional sessions disabled");
1063 	}
1064 
1065 	/*
1066 	 * A server session has no fd to read or write until a
1067 	 * CHANNEL_REQUEST for a shell is made, so we set the type to
1068 	 * SSH_CHANNEL_LARVAL.  Additionally, a callback for handling all
1069 	 * CHANNEL_REQUEST messages is registered.
1070 	 */
1071 	c = channel_new("session", SSH_CHANNEL_LARVAL,
1072 	    -1, -1, -1, /*window size*/0, CHAN_SES_PACKET_DEFAULT,
1073 	    0, "server-session", 1);
1074 	if ((options.tcp_rcv_buf_poll > 0) && (!options.hpn_disabled))
1075 		c->dynamic_window = 1;
1076 	if (session_open(the_authctxt, c->self) != 1) {
1077 		debug("session open failed, free channel %d", c->self);
1078 		channel_free(c);
1079 		return NULL;
1080 	}
1081 	channel_register_cleanup(c->self, session_close_by_channel, 0);
1082 	return c;
1083 }
1084 
1085 static int
1086 server_input_channel_open(int type, u_int32_t seq, void *ctxt)
1087 {
1088 	Channel *c = NULL;
1089 	char *ctype;
1090 	int rchan;
1091 	u_int rmaxpack, rwindow, len;
1092 
1093 	ctype = packet_get_string(&len);
1094 	rchan = packet_get_int();
1095 	rwindow = packet_get_int();
1096 	rmaxpack = packet_get_int();
1097 
1098 	debug("server_input_channel_open: ctype %s rchan %d win %d max %d",
1099 	    ctype, rchan, rwindow, rmaxpack);
1100 
1101 	if (strcmp(ctype, "session") == 0) {
1102 		c = server_request_session();
1103 	} else if (strcmp(ctype, "direct-tcpip") == 0) {
1104 		c = server_request_direct_tcpip();
1105 	} else if (strcmp(ctype, "direct-streamlocal@openssh.com") == 0) {
1106 		c = server_request_direct_streamlocal();
1107 	} else if (strcmp(ctype, "tun@openssh.com") == 0) {
1108 		c = server_request_tun();
1109 	}
1110 	if (c != NULL) {
1111 		debug("server_input_channel_open: confirm %s", ctype);
1112 		c->remote_id = rchan;
1113 		c->remote_window = rwindow;
1114 		c->remote_maxpacket = rmaxpack;
1115 		if (c->type != SSH_CHANNEL_CONNECTING) {
1116 			packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1117 			packet_put_int(c->remote_id);
1118 			packet_put_int(c->self);
1119 			packet_put_int(c->local_window);
1120 			packet_put_int(c->local_maxpacket);
1121 			packet_send();
1122 		}
1123 	} else {
1124 		debug("server_input_channel_open: failure %s", ctype);
1125 		packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1126 		packet_put_int(rchan);
1127 		packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED);
1128 		if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1129 			packet_put_cstring("open failed");
1130 			packet_put_cstring("");
1131 		}
1132 		packet_send();
1133 	}
1134 	free(ctype);
1135 	return 0;
1136 }
1137 
1138 static int
1139 server_input_hostkeys_prove(struct sshbuf **respp)
1140 {
1141 	struct ssh *ssh = active_state; /* XXX */
1142 	struct sshbuf *resp = NULL;
1143 	struct sshbuf *sigbuf = NULL;
1144 	struct sshkey *key = NULL, *key_pub = NULL, *key_prv = NULL;
1145 	int r, ndx, success = 0;
1146 	const u_char *blob;
1147 	u_char *sig = 0;
1148 	size_t blen, slen;
1149 
1150 	if ((resp = sshbuf_new()) == NULL || (sigbuf = sshbuf_new()) == NULL)
1151 		fatal("%s: sshbuf_new", __func__);
1152 
1153 	while (ssh_packet_remaining(ssh) > 0) {
1154 		sshkey_free(key);
1155 		key = NULL;
1156 		if ((r = sshpkt_get_string_direct(ssh, &blob, &blen)) != 0 ||
1157 		    (r = sshkey_from_blob(blob, blen, &key)) != 0) {
1158 			error("%s: couldn't parse key: %s",
1159 			    __func__, ssh_err(r));
1160 			goto out;
1161 		}
1162 		/*
1163 		 * Better check that this is actually one of our hostkeys
1164 		 * before attempting to sign anything with it.
1165 		 */
1166 		if ((ndx = ssh->kex->host_key_index(key, 1, ssh)) == -1) {
1167 			error("%s: unknown host %s key",
1168 			    __func__, sshkey_type(key));
1169 			goto out;
1170 		}
1171 		/*
1172 		 * XXX refactor: make kex->sign just use an index rather
1173 		 * than passing in public and private keys
1174 		 */
1175 		if ((key_prv = get_hostkey_by_index(ndx)) == NULL &&
1176 		    (key_pub = get_hostkey_public_by_index(ndx, ssh)) == NULL) {
1177 			error("%s: can't retrieve hostkey %d", __func__, ndx);
1178 			goto out;
1179 		}
1180 		sshbuf_reset(sigbuf);
1181 		free(sig);
1182 		sig = NULL;
1183 		if ((r = sshbuf_put_cstring(sigbuf,
1184 		    "hostkeys-prove-00@openssh.com")) != 0 ||
1185 		    (r = sshbuf_put_string(sigbuf,
1186 		    ssh->kex->session_id, ssh->kex->session_id_len)) != 0 ||
1187 		    (r = sshkey_puts(key, sigbuf)) != 0 ||
1188 		    (r = ssh->kex->sign(key_prv, key_pub, &sig, &slen,
1189 		    sshbuf_ptr(sigbuf), sshbuf_len(sigbuf), NULL, 0)) != 0 ||
1190 		    (r = sshbuf_put_string(resp, sig, slen)) != 0) {
1191 			error("%s: couldn't prepare signature: %s",
1192 			    __func__, ssh_err(r));
1193 			goto out;
1194 		}
1195 	}
1196 	/* Success */
1197 	*respp = resp;
1198 	resp = NULL; /* don't free it */
1199 	success = 1;
1200  out:
1201 	free(sig);
1202 	sshbuf_free(resp);
1203 	sshbuf_free(sigbuf);
1204 	sshkey_free(key);
1205 	return success;
1206 }
1207 
1208 static int
1209 server_input_global_request(int type, u_int32_t seq, void *ctxt)
1210 {
1211 	char *rtype;
1212 	int want_reply;
1213 	int r, success = 0, allocated_listen_port = 0;
1214 	struct sshbuf *resp = NULL;
1215 
1216 	rtype = packet_get_string(NULL);
1217 	want_reply = packet_get_char();
1218 	debug("server_input_global_request: rtype %s want_reply %d", rtype, want_reply);
1219 
1220 	/* -R style forwarding */
1221 	if (strcmp(rtype, "tcpip-forward") == 0) {
1222 		struct passwd *pw;
1223 		struct Forward fwd;
1224 
1225 		pw = the_authctxt->pw;
1226 		if (pw == NULL || !the_authctxt->valid)
1227 			fatal("server_input_global_request: no/invalid user");
1228 		memset(&fwd, 0, sizeof(fwd));
1229 		fwd.listen_host = packet_get_string(NULL);
1230 		fwd.listen_port = (u_short)packet_get_int();
1231 		debug("server_input_global_request: tcpip-forward listen %s port %d",
1232 		    fwd.listen_host, fwd.listen_port);
1233 
1234 		/* check permissions */
1235 		if ((options.allow_tcp_forwarding & FORWARD_REMOTE) == 0 ||
1236 		    no_port_forwarding_flag ||
1237 		    (!want_reply && fwd.listen_port == 0) ||
1238 		    (fwd.listen_port != 0 && fwd.listen_port < IPPORT_RESERVED &&
1239 		    pw->pw_uid != 0)) {
1240 			success = 0;
1241 			packet_send_debug("Server has disabled port forwarding.");
1242 		} else {
1243 			/* Start listening on the port */
1244 			success = channel_setup_remote_fwd_listener(&fwd,
1245 			    &allocated_listen_port, &options.fwd_opts);
1246 		}
1247 		free(fwd.listen_host);
1248 		if ((resp = sshbuf_new()) == NULL)
1249 			fatal("%s: sshbuf_new", __func__);
1250 		if (allocated_listen_port != 0 &&
1251 		    (r = sshbuf_put_u32(resp, allocated_listen_port)) != 0)
1252 			fatal("%s: sshbuf_put_u32: %s", __func__, ssh_err(r));
1253 	} else if (strcmp(rtype, "cancel-tcpip-forward") == 0) {
1254 		struct Forward fwd;
1255 
1256 		memset(&fwd, 0, sizeof(fwd));
1257 		fwd.listen_host = packet_get_string(NULL);
1258 		fwd.listen_port = (u_short)packet_get_int();
1259 		debug("%s: cancel-tcpip-forward addr %s port %d", __func__,
1260 		    fwd.listen_host, fwd.listen_port);
1261 
1262 		success = channel_cancel_rport_listener(&fwd);
1263 		free(fwd.listen_host);
1264 	} else if (strcmp(rtype, "streamlocal-forward@openssh.com") == 0) {
1265 		struct Forward fwd;
1266 
1267 		memset(&fwd, 0, sizeof(fwd));
1268 		fwd.listen_path = packet_get_string(NULL);
1269 		debug("server_input_global_request: streamlocal-forward listen path %s",
1270 		    fwd.listen_path);
1271 
1272 		/* check permissions */
1273 		if ((options.allow_streamlocal_forwarding & FORWARD_REMOTE) == 0
1274 		    || no_port_forwarding_flag) {
1275 			success = 0;
1276 			packet_send_debug("Server has disabled port forwarding.");
1277 		} else {
1278 			/* Start listening on the socket */
1279 			success = channel_setup_remote_fwd_listener(
1280 			    &fwd, NULL, &options.fwd_opts);
1281 		}
1282 		free(fwd.listen_path);
1283 	} else if (strcmp(rtype, "cancel-streamlocal-forward@openssh.com") == 0) {
1284 		struct Forward fwd;
1285 
1286 		memset(&fwd, 0, sizeof(fwd));
1287 		fwd.listen_path = packet_get_string(NULL);
1288 		debug("%s: cancel-streamlocal-forward path %s", __func__,
1289 		    fwd.listen_path);
1290 
1291 		success = channel_cancel_rport_listener(&fwd);
1292 		free(fwd.listen_path);
1293 	} else if (strcmp(rtype, "no-more-sessions@openssh.com") == 0) {
1294 		no_more_sessions = 1;
1295 		success = 1;
1296 	} else if (strcmp(rtype, "hostkeys-prove-00@openssh.com") == 0) {
1297 		success = server_input_hostkeys_prove(&resp);
1298 	}
1299 	if (want_reply) {
1300 		packet_start(success ?
1301 		    SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE);
1302 		if (success && resp != NULL)
1303 			ssh_packet_put_raw(active_state, sshbuf_ptr(resp),
1304 			    sshbuf_len(resp));
1305 		packet_send();
1306 		packet_write_wait();
1307 	}
1308 	free(rtype);
1309 	sshbuf_free(resp);
1310 	return 0;
1311 }
1312 
1313 static int
1314 server_input_channel_req(int type, u_int32_t seq, void *ctxt)
1315 {
1316 	Channel *c;
1317 	int id, reply, success = 0;
1318 	char *rtype;
1319 
1320 	id = packet_get_int();
1321 	rtype = packet_get_string(NULL);
1322 	reply = packet_get_char();
1323 
1324 	debug("server_input_channel_req: channel %d request %s reply %d",
1325 	    id, rtype, reply);
1326 
1327 	if ((c = channel_lookup(id)) == NULL)
1328 		packet_disconnect("server_input_channel_req: "
1329 		    "unknown channel %d", id);
1330 	if (!strcmp(rtype, "eow@openssh.com")) {
1331 		packet_check_eom();
1332 		chan_rcvd_eow(c);
1333 	} else if ((c->type == SSH_CHANNEL_LARVAL ||
1334 	    c->type == SSH_CHANNEL_OPEN) && strcmp(c->ctype, "session") == 0)
1335 		success = session_input_channel_req(c, rtype);
1336 	if (reply && !(c->flags & CHAN_CLOSE_SENT)) {
1337 		packet_start(success ?
1338 		    SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE);
1339 		packet_put_int(c->remote_id);
1340 		packet_send();
1341 	}
1342 	free(rtype);
1343 	return 0;
1344 }
1345 
1346 static void
1347 server_init_dispatch_20(void)
1348 {
1349 	debug("server_init_dispatch_20");
1350 	dispatch_init(&dispatch_protocol_error);
1351 	dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose);
1352 	dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data);
1353 	dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof);
1354 	dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data);
1355 	dispatch_set(SSH2_MSG_CHANNEL_OPEN, &server_input_channel_open);
1356 	dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
1357 	dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
1358 	dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &server_input_channel_req);
1359 	dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust);
1360 	dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &server_input_global_request);
1361 	/* client_alive */
1362 	dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, &server_input_keep_alive);
1363 	dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &server_input_keep_alive);
1364 	dispatch_set(SSH2_MSG_REQUEST_SUCCESS, &server_input_keep_alive);
1365 	dispatch_set(SSH2_MSG_REQUEST_FAILURE, &server_input_keep_alive);
1366 	/* rekeying */
1367 	dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit);
1368 }
1369 static void
1370 server_init_dispatch_13(void)
1371 {
1372 	debug("server_init_dispatch_13");
1373 	dispatch_init(NULL);
1374 	dispatch_set(SSH_CMSG_EOF, &server_input_eof);
1375 	dispatch_set(SSH_CMSG_STDIN_DATA, &server_input_stdin_data);
1376 	dispatch_set(SSH_CMSG_WINDOW_SIZE, &server_input_window_size);
1377 	dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close);
1378 	dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation);
1379 	dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data);
1380 	dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
1381 	dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
1382 	dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open);
1383 }
1384 static void
1385 server_init_dispatch_15(void)
1386 {
1387 	server_init_dispatch_13();
1388 	debug("server_init_dispatch_15");
1389 	dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof);
1390 	dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_oclose);
1391 }
1392 static void
1393 server_init_dispatch(void)
1394 {
1395 	if (compat20)
1396 		server_init_dispatch_20();
1397 	else if (compat13)
1398 		server_init_dispatch_13();
1399 	else
1400 		server_init_dispatch_15();
1401 }
1402