xref: /netbsd-src/crypto/external/bsd/openssh/dist/serverloop.c (revision d909946ca08dceb44d7d0f22ec9488679695d976)
1 /*	$NetBSD: serverloop.c,v 1.15 2016/08/02 13:45:12 christos Exp $	*/
2 /* $OpenBSD: serverloop.c,v 1.184 2016/03/07 19:02:43 djm Exp $ */
3 /*
4  * Author: Tatu Ylonen <ylo@cs.hut.fi>
5  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
6  *                    All rights reserved
7  * Server main loop for handling the interactive session.
8  *
9  * As far as I am concerned, the code I have written for this software
10  * can be used freely for any purpose.  Any derived versions of this
11  * software must be clearly marked as such, and if the derived work is
12  * incompatible with the protocol description in the RFC file, it must be
13  * called by a name other than "ssh" or "Secure Shell".
14  *
15  * SSH2 support by Markus Friedl.
16  * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
17  *
18  * Redistribution and use in source and binary forms, with or without
19  * modification, are permitted provided that the following conditions
20  * are met:
21  * 1. Redistributions of source code must retain the above copyright
22  *    notice, this list of conditions and the following disclaimer.
23  * 2. Redistributions in binary form must reproduce the above copyright
24  *    notice, this list of conditions and the following disclaimer in the
25  *    documentation and/or other materials provided with the distribution.
26  *
27  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
28  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
29  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
30  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
31  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
32  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
33  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
34  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
35  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
36  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
37  */
38 
39 #include "includes.h"
40 __RCSID("$NetBSD: serverloop.c,v 1.15 2016/08/02 13:45:12 christos Exp $");
41 #include <sys/param.h>	/* MIN MAX */
42 #include <sys/types.h>
43 #include <sys/wait.h>
44 #include <sys/socket.h>
45 #include <sys/time.h>
46 #include <sys/queue.h>
47 
48 #include <netinet/in.h>
49 
50 #include <errno.h>
51 #include <fcntl.h>
52 #include <pwd.h>
53 #include <signal.h>
54 #include <string.h>
55 #include <termios.h>
56 #include <unistd.h>
57 #include <stdarg.h>
58 
59 #include "xmalloc.h"
60 #include "packet.h"
61 #include "buffer.h"
62 #include "log.h"
63 #include "misc.h"
64 #include "servconf.h"
65 #include "canohost.h"
66 #include "sshpty.h"
67 #include "channels.h"
68 #include "compat.h"
69 #include "ssh1.h"
70 #include "ssh2.h"
71 #include "key.h"
72 #include "cipher.h"
73 #include "kex.h"
74 #include "hostfile.h"
75 #include "auth.h"
76 #include "session.h"
77 #include "dispatch.h"
78 #include "auth-options.h"
79 #include "serverloop.h"
80 #include "ssherr.h"
81 
82 extern ServerOptions options;
83 
84 /* XXX */
85 extern Authctxt *the_authctxt;
86 extern int use_privsep;
87 
88 static Buffer stdin_buffer;	/* Buffer for stdin data. */
89 static Buffer stdout_buffer;	/* Buffer for stdout data. */
90 static Buffer stderr_buffer;	/* Buffer for stderr data. */
91 static int fdin;		/* Descriptor for stdin (for writing) */
92 static int fdout;		/* Descriptor for stdout (for reading);
93 				   May be same number as fdin. */
94 static int fderr;		/* Descriptor for stderr.  May be -1. */
95 static u_long stdin_bytes = 0;	/* Number of bytes written to stdin. */
96 static u_long stdout_bytes = 0;	/* Number of stdout bytes sent to client. */
97 static u_long stderr_bytes = 0;	/* Number of stderr bytes sent to client. */
98 static u_long fdout_bytes = 0;	/* Number of stdout bytes read from program. */
99 static int stdin_eof = 0;	/* EOF message received from client. */
100 static int fdout_eof = 0;	/* EOF encountered reading from fdout. */
101 static int fderr_eof = 0;	/* EOF encountered readung from fderr. */
102 static int fdin_is_tty = 0;	/* fdin points to a tty. */
103 static int connection_in;	/* Connection to client (input). */
104 static int connection_out;	/* Connection to client (output). */
105 static int connection_closed = 0;	/* Connection to client closed. */
106 static u_int buffer_high;	/* "Soft" max buffer size. */
107 static int no_more_sessions = 0; /* Disallow further sessions. */
108 
109 /*
110  * This SIGCHLD kludge is used to detect when the child exits.  The server
111  * will exit after that, as soon as forwarded connections have terminated.
112  */
113 
114 static volatile sig_atomic_t child_terminated = 0;	/* The child has terminated. */
115 
116 /* Cleanup on signals (!use_privsep case only) */
117 static volatile sig_atomic_t received_sigterm = 0;
118 
119 /* prototypes */
120 static void server_init_dispatch(void);
121 
122 /*
123  * Returns current time in seconds from Jan 1, 1970 with the maximum
124  * available resolution.
125  */
126 
127 static double
128 get_current_time(void)
129 {
130 	struct timeval tv;
131 	gettimeofday(&tv, NULL);
132 	return (double) tv.tv_sec + (double) tv.tv_usec / 1000000.0;
133 }
134 
135 /*
136  * we write to this pipe if a SIGCHLD is caught in order to avoid
137  * the race between select() and child_terminated
138  */
139 static int notify_pipe[2];
140 static void
141 notify_setup(void)
142 {
143 	if (pipe(notify_pipe) < 0) {
144 		error("pipe(notify_pipe) failed %s", strerror(errno));
145 	} else if ((fcntl(notify_pipe[0], F_SETFD, FD_CLOEXEC) == -1) ||
146 	    (fcntl(notify_pipe[1], F_SETFD, FD_CLOEXEC) == -1)) {
147 		error("fcntl(notify_pipe, F_SETFD) failed %s", strerror(errno));
148 		close(notify_pipe[0]);
149 		close(notify_pipe[1]);
150 	} else {
151 		set_nonblock(notify_pipe[0]);
152 		set_nonblock(notify_pipe[1]);
153 		return;
154 	}
155 	notify_pipe[0] = -1;	/* read end */
156 	notify_pipe[1] = -1;	/* write end */
157 }
158 static void
159 notify_parent(void)
160 {
161 	if (notify_pipe[1] != -1)
162 		(void)write(notify_pipe[1], "", 1);
163 }
164 static void
165 notify_prepare(fd_set *readset)
166 {
167 	if (notify_pipe[0] != -1)
168 		FD_SET(notify_pipe[0], readset);
169 }
170 static void
171 notify_done(fd_set *readset)
172 {
173 	char c;
174 
175 	if (notify_pipe[0] != -1 && FD_ISSET(notify_pipe[0], readset))
176 		while (read(notify_pipe[0], &c, 1) != -1)
177 			debug2("notify_done: reading");
178 }
179 
180 /*ARGSUSED*/
181 static void
182 sigchld_handler(int sig)
183 {
184 	int save_errno = errno;
185 	child_terminated = 1;
186 	signal(SIGCHLD, sigchld_handler);
187 	notify_parent();
188 	errno = save_errno;
189 }
190 
191 /*ARGSUSED*/
192 static void
193 sigterm_handler(int sig)
194 {
195 	received_sigterm = sig;
196 }
197 
198 /*
199  * Make packets from buffered stderr data, and buffer it for sending
200  * to the client.
201  */
202 static void
203 make_packets_from_stderr_data(void)
204 {
205 	u_int len;
206 
207 	/* Send buffered stderr data to the client. */
208 	while (buffer_len(&stderr_buffer) > 0 &&
209 	    packet_not_very_much_data_to_write()) {
210 		len = buffer_len(&stderr_buffer);
211 		if (packet_is_interactive()) {
212 			if (len > 512)
213 				len = 512;
214 		} else {
215 			/* Keep the packets at reasonable size. */
216 			if (len > packet_get_maxsize())
217 				len = packet_get_maxsize();
218 		}
219 		packet_start(SSH_SMSG_STDERR_DATA);
220 		packet_put_string(buffer_ptr(&stderr_buffer), len);
221 		packet_send();
222 		buffer_consume(&stderr_buffer, len);
223 		stderr_bytes += len;
224 	}
225 }
226 
227 /*
228  * Make packets from buffered stdout data, and buffer it for sending to the
229  * client.
230  */
231 static void
232 make_packets_from_stdout_data(void)
233 {
234 	u_int len;
235 
236 	/* Send buffered stdout data to the client. */
237 	while (buffer_len(&stdout_buffer) > 0 &&
238 	    packet_not_very_much_data_to_write()) {
239 		len = buffer_len(&stdout_buffer);
240 		if (packet_is_interactive()) {
241 			if (len > 512)
242 				len = 512;
243 		} else {
244 			/* Keep the packets at reasonable size. */
245 			if (len > packet_get_maxsize())
246 				len = packet_get_maxsize();
247 		}
248 		packet_start(SSH_SMSG_STDOUT_DATA);
249 		packet_put_string(buffer_ptr(&stdout_buffer), len);
250 		packet_send();
251 		buffer_consume(&stdout_buffer, len);
252 		stdout_bytes += len;
253 	}
254 }
255 
256 static void
257 client_alive_check(void)
258 {
259 	int channel_id;
260 
261 	/* timeout, check to see how many we have had */
262 	if (packet_inc_alive_timeouts() > options.client_alive_count_max) {
263 		logit("Timeout, client not responding.");
264 		cleanup_exit(255);
265 	}
266 
267 	/*
268 	 * send a bogus global/channel request with "wantreply",
269 	 * we should get back a failure
270 	 */
271 	if ((channel_id = channel_find_open()) == -1) {
272 		packet_start(SSH2_MSG_GLOBAL_REQUEST);
273 		packet_put_cstring("keepalive@openssh.com");
274 		packet_put_char(1);	/* boolean: want reply */
275 	} else {
276 		channel_request_start(channel_id, "keepalive@openssh.com", 1);
277 	}
278 	packet_send();
279 }
280 
281 /*
282  * Sleep in select() until we can do something.  This will initialize the
283  * select masks.  Upon return, the masks will indicate which descriptors
284  * have data or can accept data.  Optionally, a maximum time can be specified
285  * for the duration of the wait (0 = infinite).
286  */
287 static void
288 wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
289     u_int *nallocp, u_int64_t max_time_ms)
290 {
291 	struct timeval tv, *tvp;
292 	int ret;
293 	time_t minwait_secs = 0;
294 	int client_alive_scheduled = 0;
295 
296 	/* Allocate and update select() masks for channel descriptors. */
297 	channel_prepare_select(readsetp, writesetp, maxfdp, nallocp,
298 	    &minwait_secs, 0);
299 
300 	/* XXX need proper deadline system for rekey/client alive */
301 	if (minwait_secs != 0)
302 		max_time_ms = MIN(max_time_ms, (u_int)minwait_secs * 1000);
303 
304 	/*
305 	 * if using client_alive, set the max timeout accordingly,
306 	 * and indicate that this particular timeout was for client
307 	 * alive by setting the client_alive_scheduled flag.
308 	 *
309 	 * this could be randomized somewhat to make traffic
310 	 * analysis more difficult, but we're not doing it yet.
311 	 */
312 	if (compat20 && options.client_alive_interval) {
313 		uint64_t keepalive_ms =
314 		    (uint64_t)options.client_alive_interval * 1000;
315 
316 		client_alive_scheduled = 1;
317 		if (max_time_ms == 0 || max_time_ms > keepalive_ms)
318 			max_time_ms = keepalive_ms;
319 	}
320 
321 	if (compat20) {
322 #if 0
323 		/* wrong: bad condition XXX */
324 		if (channel_not_very_much_buffered_data())
325 #endif
326 		FD_SET(connection_in, *readsetp);
327 	} else {
328 		/*
329 		 * Read packets from the client unless we have too much
330 		 * buffered stdin or channel data.
331 		 */
332 		if (buffer_len(&stdin_buffer) < buffer_high &&
333 		    channel_not_very_much_buffered_data())
334 			FD_SET(connection_in, *readsetp);
335 		/*
336 		 * If there is not too much data already buffered going to
337 		 * the client, try to get some more data from the program.
338 		 */
339 		if (packet_not_very_much_data_to_write()) {
340 			if (!fdout_eof)
341 				FD_SET(fdout, *readsetp);
342 			if (!fderr_eof)
343 				FD_SET(fderr, *readsetp);
344 		}
345 		/*
346 		 * If we have buffered data, try to write some of that data
347 		 * to the program.
348 		 */
349 		if (fdin != -1 && buffer_len(&stdin_buffer) > 0)
350 			FD_SET(fdin, *writesetp);
351 	}
352 	notify_prepare(*readsetp);
353 
354 	/*
355 	 * If we have buffered packet data going to the client, mark that
356 	 * descriptor.
357 	 */
358 	if (packet_have_data_to_write())
359 		FD_SET(connection_out, *writesetp);
360 
361 	/*
362 	 * If child has terminated and there is enough buffer space to read
363 	 * from it, then read as much as is available and exit.
364 	 */
365 	if (child_terminated && packet_not_very_much_data_to_write())
366 		if (max_time_ms == 0 || client_alive_scheduled)
367 			max_time_ms = 100;
368 
369 	if (max_time_ms == 0)
370 		tvp = NULL;
371 	else {
372 		tv.tv_sec = max_time_ms / 1000;
373 		tv.tv_usec = 1000 * (max_time_ms % 1000);
374 		tvp = &tv;
375 	}
376 
377 	/* Wait for something to happen, or the timeout to expire. */
378 	ret = select((*maxfdp)+1, *readsetp, *writesetp, NULL, tvp);
379 
380 	if (ret == -1) {
381 		memset(*readsetp, 0, *nallocp);
382 		memset(*writesetp, 0, *nallocp);
383 		if (errno != EINTR)
384 			error("select: %.100s", strerror(errno));
385 	} else if (ret == 0 && client_alive_scheduled)
386 		client_alive_check();
387 
388 	notify_done(*readsetp);
389 }
390 
391 /*
392  * Processes input from the client and the program.  Input data is stored
393  * in buffers and processed later.
394  */
395 static void
396 process_input(fd_set *readset)
397 {
398 	struct ssh *ssh = active_state; /* XXX */
399 	int len;
400 	char buf[16384];
401 
402 	/* Read and buffer any input data from the client. */
403 	if (FD_ISSET(connection_in, readset)) {
404 		len = read(connection_in, buf, sizeof(buf));
405 		if (len == 0) {
406 			verbose("Connection closed by %.100s port %d",
407 			    ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
408 			connection_closed = 1;
409 			if (compat20)
410 				return;
411 			cleanup_exit(255);
412 		} else if (len < 0) {
413 			if (errno != EINTR && errno != EAGAIN) {
414 				verbose("Read error from remote host "
415 				    "%.100s port %d: %.100s",
416 				    ssh_remote_ipaddr(ssh),
417 				    ssh_remote_port(ssh), strerror(errno));
418 				cleanup_exit(255);
419 			}
420 		} else {
421 			/* Buffer any received data. */
422 			packet_process_incoming(buf, len);
423 			fdout_bytes += len;
424 		}
425 	}
426 	if (compat20)
427 		return;
428 
429 	/* Read and buffer any available stdout data from the program. */
430 	if (!fdout_eof && FD_ISSET(fdout, readset)) {
431 		len = read(fdout, buf, sizeof(buf));
432 		if (len < 0 && (errno == EINTR || errno == EAGAIN)) {
433 			/* do nothing */
434 		} else if (len <= 0) {
435 			fdout_eof = 1;
436 		} else {
437 			buffer_append(&stdout_buffer, buf, len);
438 			debug ("FD out now: %ld", fdout_bytes);
439 			fdout_bytes += len;
440 		}
441 	}
442 	/* Read and buffer any available stderr data from the program. */
443 	if (!fderr_eof && FD_ISSET(fderr, readset)) {
444 		len = read(fderr, buf, sizeof(buf));
445 		if (len < 0 && (errno == EINTR || errno == EAGAIN)) {
446 			/* do nothing */
447 		} else if (len <= 0) {
448 			fderr_eof = 1;
449 		} else {
450 			buffer_append(&stderr_buffer, buf, len);
451 		}
452 	}
453 }
454 
455 /*
456  * Sends data from internal buffers to client program stdin.
457  */
458 static void
459 process_output(fd_set *writeset)
460 {
461 	struct termios tio;
462 	u_char *data;
463 	u_int dlen;
464 	int len;
465 
466 	/* Write buffered data to program stdin. */
467 	if (!compat20 && fdin != -1 && FD_ISSET(fdin, writeset)) {
468 		data = buffer_ptr(&stdin_buffer);
469 		dlen = buffer_len(&stdin_buffer);
470 		len = write(fdin, data, dlen);
471 		if (len < 0 && (errno == EINTR || errno == EAGAIN)) {
472 			/* do nothing */
473 		} else if (len <= 0) {
474 			if (fdin != fdout)
475 				close(fdin);
476 			else
477 				shutdown(fdin, SHUT_WR); /* We will no longer send. */
478 			fdin = -1;
479 		} else {
480 			/* Successful write. */
481 			if (fdin_is_tty && dlen >= 1 && data[0] != '\r' &&
482 			    tcgetattr(fdin, &tio) == 0 &&
483 			    !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
484 				/*
485 				 * Simulate echo to reduce the impact of
486 				 * traffic analysis
487 				 */
488 				packet_send_ignore(len);
489 				packet_send();
490 			}
491 			/* Consume the data from the buffer. */
492 			buffer_consume(&stdin_buffer, len);
493 			/* Update the count of bytes written to the program. */
494 			stdin_bytes += len;
495 		}
496 	}
497 	/* Send any buffered packet data to the client. */
498 	if (FD_ISSET(connection_out, writeset))
499 		stdin_bytes += packet_write_poll();
500 }
501 
502 /*
503  * Wait until all buffered output has been sent to the client.
504  * This is used when the program terminates.
505  */
506 static void
507 drain_output(void)
508 {
509 	/* Send any buffered stdout data to the client. */
510 	if (buffer_len(&stdout_buffer) > 0) {
511 		packet_start(SSH_SMSG_STDOUT_DATA);
512 		packet_put_string(buffer_ptr(&stdout_buffer),
513 				  buffer_len(&stdout_buffer));
514 		packet_send();
515 		/* Update the count of sent bytes. */
516 		stdout_bytes += buffer_len(&stdout_buffer);
517 	}
518 	/* Send any buffered stderr data to the client. */
519 	if (buffer_len(&stderr_buffer) > 0) {
520 		packet_start(SSH_SMSG_STDERR_DATA);
521 		packet_put_string(buffer_ptr(&stderr_buffer),
522 				  buffer_len(&stderr_buffer));
523 		packet_send();
524 		/* Update the count of sent bytes. */
525 		stderr_bytes += buffer_len(&stderr_buffer);
526 	}
527 	/* Wait until all buffered data has been written to the client. */
528 	packet_write_wait();
529 }
530 
531 static void
532 process_buffered_input_packets(void)
533 {
534 	dispatch_run(DISPATCH_NONBLOCK, NULL, active_state);
535 }
536 
537 /*
538  * Performs the interactive session.  This handles data transmission between
539  * the client and the program.  Note that the notion of stdin, stdout, and
540  * stderr in this function is sort of reversed: this function writes to
541  * stdin (of the child program), and reads from stdout and stderr (of the
542  * child program).
543  */
544 void
545 server_loop(pid_t pid, int fdin_arg, int fdout_arg, int fderr_arg)
546 {
547 	fd_set *readset = NULL, *writeset = NULL;
548 	int max_fd = 0;
549 	u_int nalloc = 0;
550 	int wait_status;	/* Status returned by wait(). */
551 	pid_t wait_pid;		/* pid returned by wait(). */
552 	int waiting_termination = 0;	/* Have displayed waiting close message. */
553 	u_int64_t max_time_milliseconds;
554 	u_int previous_stdout_buffer_bytes;
555 	u_int stdout_buffer_bytes;
556 	int type;
557 
558 	debug("Entering interactive session.");
559 
560 	/* Initialize the SIGCHLD kludge. */
561 	child_terminated = 0;
562 	signal(SIGCHLD, sigchld_handler);
563 
564 	if (!use_privsep) {
565 		signal(SIGTERM, sigterm_handler);
566 		signal(SIGINT, sigterm_handler);
567 		signal(SIGQUIT, sigterm_handler);
568 	}
569 
570 	/* Initialize our global variables. */
571 	fdin = fdin_arg;
572 	fdout = fdout_arg;
573 	fderr = fderr_arg;
574 
575 	/* nonblocking IO */
576 	set_nonblock(fdin);
577 	set_nonblock(fdout);
578 	/* we don't have stderr for interactive terminal sessions, see below */
579 	if (fderr != -1)
580 		set_nonblock(fderr);
581 
582 	if (!(datafellows & SSH_BUG_IGNOREMSG) && isatty(fdin))
583 		fdin_is_tty = 1;
584 
585 	connection_in = packet_get_connection_in();
586 	connection_out = packet_get_connection_out();
587 
588 	notify_setup();
589 
590 	previous_stdout_buffer_bytes = 0;
591 
592 	/* Set approximate I/O buffer size. */
593 	if (packet_is_interactive())
594 		buffer_high = 4096;
595 	else
596 		buffer_high = 64 * 1024;
597 
598 #if 0
599 	/* Initialize max_fd to the maximum of the known file descriptors. */
600 	max_fd = MAX(connection_in, connection_out);
601 	max_fd = MAX(max_fd, fdin);
602 	max_fd = MAX(max_fd, fdout);
603 	if (fderr != -1)
604 		max_fd = MAX(max_fd, fderr);
605 #endif
606 
607 	/* Initialize Initialize buffers. */
608 	buffer_init(&stdin_buffer);
609 	buffer_init(&stdout_buffer);
610 	buffer_init(&stderr_buffer);
611 
612 	/*
613 	 * If we have no separate fderr (which is the case when we have a pty
614 	 * - there we cannot make difference between data sent to stdout and
615 	 * stderr), indicate that we have seen an EOF from stderr.  This way
616 	 * we don't need to check the descriptor everywhere.
617 	 */
618 	if (fderr == -1)
619 		fderr_eof = 1;
620 
621 	server_init_dispatch();
622 
623 	/* Main loop of the server for the interactive session mode. */
624 	for (;;) {
625 
626 		/* Process buffered packets from the client. */
627 		process_buffered_input_packets();
628 
629 		/*
630 		 * If we have received eof, and there is no more pending
631 		 * input data, cause a real eof by closing fdin.
632 		 */
633 		if (stdin_eof && fdin != -1 && buffer_len(&stdin_buffer) == 0) {
634 			if (fdin != fdout)
635 				close(fdin);
636 			else
637 				shutdown(fdin, SHUT_WR); /* We will no longer send. */
638 			fdin = -1;
639 		}
640 		/* Make packets from buffered stderr data to send to the client. */
641 		make_packets_from_stderr_data();
642 
643 		/*
644 		 * Make packets from buffered stdout data to send to the
645 		 * client. If there is very little to send, this arranges to
646 		 * not send them now, but to wait a short while to see if we
647 		 * are getting more data. This is necessary, as some systems
648 		 * wake up readers from a pty after each separate character.
649 		 */
650 		max_time_milliseconds = 0;
651 		stdout_buffer_bytes = buffer_len(&stdout_buffer);
652 		if (stdout_buffer_bytes != 0 && stdout_buffer_bytes < 256 &&
653 		    stdout_buffer_bytes != previous_stdout_buffer_bytes) {
654 			/* try again after a while */
655 			max_time_milliseconds = 10;
656 		} else {
657 			/* Send it now. */
658 			make_packets_from_stdout_data();
659 		}
660 		previous_stdout_buffer_bytes = buffer_len(&stdout_buffer);
661 
662 		/* Send channel data to the client. */
663 		if (packet_not_very_much_data_to_write())
664 			channel_output_poll();
665 
666 		/*
667 		 * Bail out of the loop if the program has closed its output
668 		 * descriptors, and we have no more data to send to the
669 		 * client, and there is no pending buffered data.
670 		 */
671 		if (fdout_eof && fderr_eof && !packet_have_data_to_write() &&
672 		    buffer_len(&stdout_buffer) == 0 && buffer_len(&stderr_buffer) == 0) {
673 			if (!channel_still_open())
674 				break;
675 			if (!waiting_termination) {
676 				const char *s = "Waiting for forwarded connections to terminate...\r\n";
677 				char *cp;
678 				waiting_termination = 1;
679 				buffer_append(&stderr_buffer, s, strlen(s));
680 
681 				/* Display list of open channels. */
682 				cp = channel_open_message();
683 				buffer_append(&stderr_buffer, cp, strlen(cp));
684 				free(cp);
685 			}
686 		}
687 		max_fd = MAX(connection_in, connection_out);
688 		max_fd = MAX(max_fd, fdin);
689 		max_fd = MAX(max_fd, fdout);
690 		max_fd = MAX(max_fd, fderr);
691 		max_fd = MAX(max_fd, notify_pipe[0]);
692 
693 		/* Sleep in select() until we can do something. */
694 		wait_until_can_do_something(&readset, &writeset, &max_fd,
695 		    &nalloc, max_time_milliseconds);
696 
697 		if (received_sigterm) {
698 			logit("Exiting on signal %d", (int)received_sigterm);
699 			/* Clean up sessions, utmp, etc. */
700 			cleanup_exit(255);
701 		}
702 
703 		/* Process any channel events. */
704 		channel_after_select(readset, writeset);
705 
706 		/* Process input from the client and from program stdout/stderr. */
707 		process_input(readset);
708 
709 		/* Process output to the client and to program stdin. */
710 		process_output(writeset);
711 	}
712 	free(readset);
713 	free(writeset);
714 
715 	/* Cleanup and termination code. */
716 
717 	/* Wait until all output has been sent to the client. */
718 	drain_output();
719 
720 	debug("End of interactive session; stdin %ld, stdout (read %ld, sent %ld), stderr %ld bytes.",
721 	    stdin_bytes, fdout_bytes, stdout_bytes, stderr_bytes);
722 
723 	/* Free and clear the buffers. */
724 	buffer_free(&stdin_buffer);
725 	buffer_free(&stdout_buffer);
726 	buffer_free(&stderr_buffer);
727 
728 	/* Close the file descriptors. */
729 	if (fdout != -1)
730 		close(fdout);
731 	fdout = -1;
732 	fdout_eof = 1;
733 	if (fderr != -1)
734 		close(fderr);
735 	fderr = -1;
736 	fderr_eof = 1;
737 	if (fdin != -1)
738 		close(fdin);
739 	fdin = -1;
740 
741 	channel_free_all();
742 
743 	/* We no longer want our SIGCHLD handler to be called. */
744 	signal(SIGCHLD, SIG_DFL);
745 
746 	while ((wait_pid = waitpid(-1, &wait_status, 0)) < 0)
747 		if (errno != EINTR)
748 			packet_disconnect("wait: %.100s", strerror(errno));
749 	if (wait_pid != pid)
750 		error("Strange, wait returned pid %ld, expected %ld",
751 		    (long)wait_pid, (long)pid);
752 
753 	/* Check if it exited normally. */
754 	if (WIFEXITED(wait_status)) {
755 		/* Yes, normal exit.  Get exit status and send it to the client. */
756 		debug("Command exited with status %d.", WEXITSTATUS(wait_status));
757 		packet_start(SSH_SMSG_EXITSTATUS);
758 		packet_put_int(WEXITSTATUS(wait_status));
759 		packet_send();
760 		packet_write_wait();
761 
762 		/*
763 		 * Wait for exit confirmation.  Note that there might be
764 		 * other packets coming before it; however, the program has
765 		 * already died so we just ignore them.  The client is
766 		 * supposed to respond with the confirmation when it receives
767 		 * the exit status.
768 		 */
769 		do {
770 			type = packet_read();
771 		}
772 		while (type != SSH_CMSG_EXIT_CONFIRMATION);
773 
774 		debug("Received exit confirmation.");
775 		return;
776 	}
777 	/* Check if the program terminated due to a signal. */
778 	if (WIFSIGNALED(wait_status))
779 		packet_disconnect("Command terminated on signal %d.",
780 				  WTERMSIG(wait_status));
781 
782 	/* Some weird exit cause.  Just exit. */
783 	packet_disconnect("wait returned status %04x.", wait_status);
784 	/* NOTREACHED */
785 }
786 
787 static void
788 collect_children(void)
789 {
790 	pid_t pid;
791 	sigset_t oset, nset;
792 	int status;
793 
794 	/* block SIGCHLD while we check for dead children */
795 	sigemptyset(&nset);
796 	sigaddset(&nset, SIGCHLD);
797 	sigprocmask(SIG_BLOCK, &nset, &oset);
798 	if (child_terminated) {
799 		debug("Received SIGCHLD.");
800 		while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
801 		    (pid < 0 && errno == EINTR))
802 			if (pid > 0)
803 				session_close_by_pid(pid, status);
804 		child_terminated = 0;
805 	}
806 	sigprocmask(SIG_SETMASK, &oset, NULL);
807 }
808 
809 void
810 server_loop2(Authctxt *authctxt)
811 {
812 	fd_set *readset = NULL, *writeset = NULL;
813 	int max_fd;
814 	u_int nalloc = 0;
815 	u_int64_t rekey_timeout_ms = 0;
816 	double start_time, total_time;
817 	struct ssh *ssh = active_state; /* XXX */
818 
819 	debug("Entering interactive session for SSH2.");
820 	start_time = get_current_time();
821 
822 	signal(SIGCHLD, sigchld_handler);
823 	child_terminated = 0;
824 	connection_in = packet_get_connection_in();
825 	connection_out = packet_get_connection_out();
826 
827 	if (!use_privsep) {
828 		signal(SIGTERM, sigterm_handler);
829 		signal(SIGINT, sigterm_handler);
830 		signal(SIGQUIT, sigterm_handler);
831 	}
832 
833 	notify_setup();
834 
835 	max_fd = MAX(connection_in, connection_out);
836 	max_fd = MAX(max_fd, notify_pipe[0]);
837 
838 	server_init_dispatch();
839 
840 	for (;;) {
841 		process_buffered_input_packets();
842 
843 		if (!ssh_packet_is_rekeying(active_state) &&
844 		    packet_not_very_much_data_to_write())
845 			channel_output_poll();
846 		if (options.rekey_interval > 0 && compat20 &&
847 		    !ssh_packet_is_rekeying(active_state))
848 			rekey_timeout_ms = packet_get_rekey_timeout() * 1000;
849 		else
850 			rekey_timeout_ms = 0;
851 
852 		wait_until_can_do_something(&readset, &writeset, &max_fd,
853 		    &nalloc, rekey_timeout_ms);
854 
855 		if (received_sigterm) {
856 			logit("Exiting on signal %d", (int)received_sigterm);
857 			/* Clean up sessions, utmp, etc. */
858 			cleanup_exit(255);
859 		}
860 
861 		collect_children();
862 		if (!ssh_packet_is_rekeying(active_state))
863 			channel_after_select(readset, writeset);
864 		process_input(readset);
865 		if (connection_closed)
866 			break;
867 		process_output(writeset);
868 	}
869 	collect_children();
870 
871 	free(readset);
872 	free(writeset);
873 
874 	/* free all channels, no more reads and writes */
875 	channel_free_all();
876 
877 	/* free remaining sessions, e.g. remove wtmp entries */
878 	session_destroy_all(NULL);
879 	total_time = get_current_time() - start_time;
880 	logit("SSH: Server;LType: Throughput;Remote: %s-%d;IN: %lu;OUT: %lu;Duration: %.1f;tPut_in: %.1f;tPut_out: %.1f",
881 	      ssh_remote_ipaddr(ssh), ssh_remote_port(ssh),
882 	      stdin_bytes, fdout_bytes, total_time, stdin_bytes / total_time,
883 	      fdout_bytes / total_time);
884 }
885 
886 static int
887 server_input_keep_alive(int type, u_int32_t seq, void *ctxt)
888 {
889 	debug("Got %d/%u for keepalive", type, seq);
890 	/*
891 	 * reset timeout, since we got a sane answer from the client.
892 	 * even if this was generated by something other than
893 	 * the bogus CHANNEL_REQUEST we send for keepalives.
894 	 */
895 	packet_set_alive_timeouts(0);
896 	return 0;
897 }
898 
899 static int
900 server_input_stdin_data(int type, u_int32_t seq, void *ctxt)
901 {
902 	char *data;
903 	u_int data_len;
904 
905 	/* Stdin data from the client.  Append it to the buffer. */
906 	/* Ignore any data if the client has closed stdin. */
907 	if (fdin == -1)
908 		return 0;
909 	data = packet_get_string(&data_len);
910 	packet_check_eom();
911 	buffer_append(&stdin_buffer, data, data_len);
912 	explicit_bzero(data, data_len);
913 	free(data);
914 	return 0;
915 }
916 
917 static int
918 server_input_eof(int type, u_int32_t seq, void *ctxt)
919 {
920 	/*
921 	 * Eof from the client.  The stdin descriptor to the
922 	 * program will be closed when all buffered data has
923 	 * drained.
924 	 */
925 	debug("EOF received for stdin.");
926 	packet_check_eom();
927 	stdin_eof = 1;
928 	return 0;
929 }
930 
931 static int
932 server_input_window_size(int type, u_int32_t seq, void *ctxt)
933 {
934 	u_int row = packet_get_int();
935 	u_int col = packet_get_int();
936 	u_int xpixel = packet_get_int();
937 	u_int ypixel = packet_get_int();
938 
939 	debug("Window change received.");
940 	packet_check_eom();
941 	if (fdin != -1)
942 		pty_change_window_size(fdin, row, col, xpixel, ypixel);
943 	return 0;
944 }
945 
946 static Channel *
947 server_request_direct_tcpip(void)
948 {
949 	Channel *c = NULL;
950 	char *target, *originator;
951 	u_short target_port, originator_port;
952 
953 	target = packet_get_string(NULL);
954 	target_port = packet_get_int();
955 	originator = packet_get_string(NULL);
956 	originator_port = packet_get_int();
957 	packet_check_eom();
958 
959 	debug("server_request_direct_tcpip: originator %s port %d, target %s "
960 	    "port %d", originator, originator_port, target, target_port);
961 
962 	/* XXX fine grained permissions */
963 	if ((options.allow_tcp_forwarding & FORWARD_LOCAL) != 0 &&
964 	    !no_port_forwarding_flag) {
965 		c = channel_connect_to_port(target, target_port,
966 		    "direct-tcpip", "direct-tcpip");
967 	} else {
968 		logit("refused local port forward: "
969 		    "originator %s port %d, target %s port %d",
970 		    originator, originator_port, target, target_port);
971 	}
972 
973 	free(originator);
974 	free(target);
975 
976 	return c;
977 }
978 
979 static Channel *
980 server_request_direct_streamlocal(void)
981 {
982 	Channel *c = NULL;
983 	char *target, *originator;
984 	u_short originator_port;
985 
986 	target = packet_get_string(NULL);
987 	originator = packet_get_string(NULL);
988 	originator_port = packet_get_int();
989 	packet_check_eom();
990 
991 	debug("server_request_direct_streamlocal: originator %s port %d, target %s",
992 	    originator, originator_port, target);
993 
994 	/* XXX fine grained permissions */
995 	if ((options.allow_streamlocal_forwarding & FORWARD_LOCAL) != 0 &&
996 	    !no_port_forwarding_flag) {
997 		c = channel_connect_to_path(target,
998 		    "direct-streamlocal@openssh.com", "direct-streamlocal");
999 	} else {
1000 		logit("refused streamlocal port forward: "
1001 		    "originator %s port %d, target %s",
1002 		    originator, originator_port, target);
1003 	}
1004 
1005 	free(originator);
1006 	free(target);
1007 
1008 	return c;
1009 }
1010 
1011 static Channel *
1012 server_request_tun(void)
1013 {
1014 	Channel *c = NULL;
1015 	int mode, tun;
1016 	int sock;
1017 
1018 	mode = packet_get_int();
1019 	switch (mode) {
1020 	case SSH_TUNMODE_POINTOPOINT:
1021 	case SSH_TUNMODE_ETHERNET:
1022 		break;
1023 	default:
1024 		packet_send_debug("Unsupported tunnel device mode.");
1025 		return NULL;
1026 	}
1027 	if ((options.permit_tun & mode) == 0) {
1028 		packet_send_debug("Server has rejected tunnel device "
1029 		    "forwarding");
1030 		return NULL;
1031 	}
1032 
1033 	tun = packet_get_int();
1034 	if (forced_tun_device != -1) {
1035 		if (tun != SSH_TUNID_ANY && forced_tun_device != tun)
1036 			goto done;
1037 		tun = forced_tun_device;
1038 	}
1039 	sock = tun_open(tun, mode);
1040 	if (sock < 0)
1041 		goto done;
1042 	if (options.hpn_disabled)
1043 	c = channel_new("tun", SSH_CHANNEL_OPEN, sock, sock, -1,
1044 	    CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1);
1045 	else
1046 		c = channel_new("tun", SSH_CHANNEL_OPEN, sock, sock, -1,
1047 		    options.hpn_buffer_size, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1);
1048 	c->datagram = 1;
1049 
1050  done:
1051 	if (c == NULL)
1052 		packet_send_debug("Failed to open the tunnel device.");
1053 	return c;
1054 }
1055 
1056 static Channel *
1057 server_request_session(void)
1058 {
1059 	Channel *c;
1060 
1061 	debug("input_session_request");
1062 	packet_check_eom();
1063 
1064 	if (no_more_sessions) {
1065 		packet_disconnect("Possible attack: attempt to open a session "
1066 		    "after additional sessions disabled");
1067 	}
1068 
1069 	/*
1070 	 * A server session has no fd to read or write until a
1071 	 * CHANNEL_REQUEST for a shell is made, so we set the type to
1072 	 * SSH_CHANNEL_LARVAL.  Additionally, a callback for handling all
1073 	 * CHANNEL_REQUEST messages is registered.
1074 	 */
1075 	c = channel_new("session", SSH_CHANNEL_LARVAL,
1076 	    -1, -1, -1, /*window size*/0, CHAN_SES_PACKET_DEFAULT,
1077 	    0, "server-session", 1);
1078 	if ((options.tcp_rcv_buf_poll > 0) && (!options.hpn_disabled))
1079 		c->dynamic_window = 1;
1080 	if (session_open(the_authctxt, c->self) != 1) {
1081 		debug("session open failed, free channel %d", c->self);
1082 		channel_free(c);
1083 		return NULL;
1084 	}
1085 	channel_register_cleanup(c->self, session_close_by_channel, 0);
1086 	return c;
1087 }
1088 
1089 static int
1090 server_input_channel_open(int type, u_int32_t seq, void *ctxt)
1091 {
1092 	Channel *c = NULL;
1093 	char *ctype;
1094 	int rchan;
1095 	u_int rmaxpack, rwindow, len;
1096 
1097 	ctype = packet_get_string(&len);
1098 	rchan = packet_get_int();
1099 	rwindow = packet_get_int();
1100 	rmaxpack = packet_get_int();
1101 
1102 	debug("server_input_channel_open: ctype %s rchan %d win %d max %d",
1103 	    ctype, rchan, rwindow, rmaxpack);
1104 
1105 	if (strcmp(ctype, "session") == 0) {
1106 		c = server_request_session();
1107 	} else if (strcmp(ctype, "direct-tcpip") == 0) {
1108 		c = server_request_direct_tcpip();
1109 	} else if (strcmp(ctype, "direct-streamlocal@openssh.com") == 0) {
1110 		c = server_request_direct_streamlocal();
1111 	} else if (strcmp(ctype, "tun@openssh.com") == 0) {
1112 		c = server_request_tun();
1113 	}
1114 	if (c != NULL) {
1115 		debug("server_input_channel_open: confirm %s", ctype);
1116 		c->remote_id = rchan;
1117 		c->remote_window = rwindow;
1118 		c->remote_maxpacket = rmaxpack;
1119 		if (c->type != SSH_CHANNEL_CONNECTING) {
1120 			packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1121 			packet_put_int(c->remote_id);
1122 			packet_put_int(c->self);
1123 			packet_put_int(c->local_window);
1124 			packet_put_int(c->local_maxpacket);
1125 			packet_send();
1126 		}
1127 	} else {
1128 		debug("server_input_channel_open: failure %s", ctype);
1129 		packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1130 		packet_put_int(rchan);
1131 		packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED);
1132 		if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1133 			packet_put_cstring("open failed");
1134 			packet_put_cstring("");
1135 		}
1136 		packet_send();
1137 	}
1138 	free(ctype);
1139 	return 0;
1140 }
1141 
1142 static int
1143 server_input_hostkeys_prove(struct sshbuf **respp)
1144 {
1145 	struct ssh *ssh = active_state; /* XXX */
1146 	struct sshbuf *resp = NULL;
1147 	struct sshbuf *sigbuf = NULL;
1148 	struct sshkey *key = NULL, *key_pub = NULL, *key_prv = NULL;
1149 	int r, ndx, success = 0;
1150 	const u_char *blob;
1151 	u_char *sig = 0;
1152 	size_t blen, slen;
1153 
1154 	if ((resp = sshbuf_new()) == NULL || (sigbuf = sshbuf_new()) == NULL)
1155 		fatal("%s: sshbuf_new", __func__);
1156 
1157 	while (ssh_packet_remaining(ssh) > 0) {
1158 		sshkey_free(key);
1159 		key = NULL;
1160 		if ((r = sshpkt_get_string_direct(ssh, &blob, &blen)) != 0 ||
1161 		    (r = sshkey_from_blob(blob, blen, &key)) != 0) {
1162 			error("%s: couldn't parse key: %s",
1163 			    __func__, ssh_err(r));
1164 			goto out;
1165 		}
1166 		/*
1167 		 * Better check that this is actually one of our hostkeys
1168 		 * before attempting to sign anything with it.
1169 		 */
1170 		if ((ndx = ssh->kex->host_key_index(key, 1, ssh)) == -1) {
1171 			error("%s: unknown host %s key",
1172 			    __func__, sshkey_type(key));
1173 			goto out;
1174 		}
1175 		/*
1176 		 * XXX refactor: make kex->sign just use an index rather
1177 		 * than passing in public and private keys
1178 		 */
1179 		if ((key_prv = get_hostkey_by_index(ndx)) == NULL &&
1180 		    (key_pub = get_hostkey_public_by_index(ndx, ssh)) == NULL) {
1181 			error("%s: can't retrieve hostkey %d", __func__, ndx);
1182 			goto out;
1183 		}
1184 		sshbuf_reset(sigbuf);
1185 		free(sig);
1186 		sig = NULL;
1187 		if ((r = sshbuf_put_cstring(sigbuf,
1188 		    "hostkeys-prove-00@openssh.com")) != 0 ||
1189 		    (r = sshbuf_put_string(sigbuf,
1190 		    ssh->kex->session_id, ssh->kex->session_id_len)) != 0 ||
1191 		    (r = sshkey_puts(key, sigbuf)) != 0 ||
1192 		    (r = ssh->kex->sign(key_prv, key_pub, &sig, &slen,
1193 		    sshbuf_ptr(sigbuf), sshbuf_len(sigbuf), NULL, 0)) != 0 ||
1194 		    (r = sshbuf_put_string(resp, sig, slen)) != 0) {
1195 			error("%s: couldn't prepare signature: %s",
1196 			    __func__, ssh_err(r));
1197 			goto out;
1198 		}
1199 	}
1200 	/* Success */
1201 	*respp = resp;
1202 	resp = NULL; /* don't free it */
1203 	success = 1;
1204  out:
1205 	free(sig);
1206 	sshbuf_free(resp);
1207 	sshbuf_free(sigbuf);
1208 	sshkey_free(key);
1209 	return success;
1210 }
1211 
1212 static int
1213 server_input_global_request(int type, u_int32_t seq, void *ctxt)
1214 {
1215 	char *rtype;
1216 	int want_reply;
1217 	int r, success = 0, allocated_listen_port = 0;
1218 	struct sshbuf *resp = NULL;
1219 
1220 	rtype = packet_get_string(NULL);
1221 	want_reply = packet_get_char();
1222 	debug("server_input_global_request: rtype %s want_reply %d", rtype, want_reply);
1223 
1224 	/* -R style forwarding */
1225 	if (strcmp(rtype, "tcpip-forward") == 0) {
1226 		struct passwd *pw;
1227 		struct Forward fwd;
1228 
1229 		pw = the_authctxt->pw;
1230 		if (pw == NULL || !the_authctxt->valid)
1231 			fatal("server_input_global_request: no/invalid user");
1232 		memset(&fwd, 0, sizeof(fwd));
1233 		fwd.listen_host = packet_get_string(NULL);
1234 		fwd.listen_port = (u_short)packet_get_int();
1235 		debug("server_input_global_request: tcpip-forward listen %s port %d",
1236 		    fwd.listen_host, fwd.listen_port);
1237 
1238 		/* check permissions */
1239 		if ((options.allow_tcp_forwarding & FORWARD_REMOTE) == 0 ||
1240 		    no_port_forwarding_flag ||
1241 		    (!want_reply && fwd.listen_port == 0) ||
1242 		    (fwd.listen_port != 0 && fwd.listen_port < IPPORT_RESERVED &&
1243 		    pw->pw_uid != 0)) {
1244 			success = 0;
1245 			packet_send_debug("Server has disabled port forwarding.");
1246 		} else {
1247 			/* Start listening on the port */
1248 			success = channel_setup_remote_fwd_listener(&fwd,
1249 			    &allocated_listen_port, &options.fwd_opts);
1250 		}
1251 		free(fwd.listen_host);
1252 		if ((resp = sshbuf_new()) == NULL)
1253 			fatal("%s: sshbuf_new", __func__);
1254 		if (allocated_listen_port != 0 &&
1255 		    (r = sshbuf_put_u32(resp, allocated_listen_port)) != 0)
1256 			fatal("%s: sshbuf_put_u32: %s", __func__, ssh_err(r));
1257 	} else if (strcmp(rtype, "cancel-tcpip-forward") == 0) {
1258 		struct Forward fwd;
1259 
1260 		memset(&fwd, 0, sizeof(fwd));
1261 		fwd.listen_host = packet_get_string(NULL);
1262 		fwd.listen_port = (u_short)packet_get_int();
1263 		debug("%s: cancel-tcpip-forward addr %s port %d", __func__,
1264 		    fwd.listen_host, fwd.listen_port);
1265 
1266 		success = channel_cancel_rport_listener(&fwd);
1267 		free(fwd.listen_host);
1268 	} else if (strcmp(rtype, "streamlocal-forward@openssh.com") == 0) {
1269 		struct Forward fwd;
1270 
1271 		memset(&fwd, 0, sizeof(fwd));
1272 		fwd.listen_path = packet_get_string(NULL);
1273 		debug("server_input_global_request: streamlocal-forward listen path %s",
1274 		    fwd.listen_path);
1275 
1276 		/* check permissions */
1277 		if ((options.allow_streamlocal_forwarding & FORWARD_REMOTE) == 0
1278 		    || no_port_forwarding_flag) {
1279 			success = 0;
1280 			packet_send_debug("Server has disabled port forwarding.");
1281 		} else {
1282 			/* Start listening on the socket */
1283 			success = channel_setup_remote_fwd_listener(
1284 			    &fwd, NULL, &options.fwd_opts);
1285 		}
1286 		free(fwd.listen_path);
1287 	} else if (strcmp(rtype, "cancel-streamlocal-forward@openssh.com") == 0) {
1288 		struct Forward fwd;
1289 
1290 		memset(&fwd, 0, sizeof(fwd));
1291 		fwd.listen_path = packet_get_string(NULL);
1292 		debug("%s: cancel-streamlocal-forward path %s", __func__,
1293 		    fwd.listen_path);
1294 
1295 		success = channel_cancel_rport_listener(&fwd);
1296 		free(fwd.listen_path);
1297 	} else if (strcmp(rtype, "no-more-sessions@openssh.com") == 0) {
1298 		no_more_sessions = 1;
1299 		success = 1;
1300 	} else if (strcmp(rtype, "hostkeys-prove-00@openssh.com") == 0) {
1301 		success = server_input_hostkeys_prove(&resp);
1302 	}
1303 	if (want_reply) {
1304 		packet_start(success ?
1305 		    SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE);
1306 		if (success && resp != NULL)
1307 			ssh_packet_put_raw(active_state, sshbuf_ptr(resp),
1308 			    sshbuf_len(resp));
1309 		packet_send();
1310 		packet_write_wait();
1311 	}
1312 	free(rtype);
1313 	sshbuf_free(resp);
1314 	return 0;
1315 }
1316 
1317 static int
1318 server_input_channel_req(int type, u_int32_t seq, void *ctxt)
1319 {
1320 	Channel *c;
1321 	int id, reply, success = 0;
1322 	char *rtype;
1323 
1324 	id = packet_get_int();
1325 	rtype = packet_get_string(NULL);
1326 	reply = packet_get_char();
1327 
1328 	debug("server_input_channel_req: channel %d request %s reply %d",
1329 	    id, rtype, reply);
1330 
1331 	if ((c = channel_lookup(id)) == NULL)
1332 		packet_disconnect("server_input_channel_req: "
1333 		    "unknown channel %d", id);
1334 	if (!strcmp(rtype, "eow@openssh.com")) {
1335 		packet_check_eom();
1336 		chan_rcvd_eow(c);
1337 	} else if ((c->type == SSH_CHANNEL_LARVAL ||
1338 	    c->type == SSH_CHANNEL_OPEN) && strcmp(c->ctype, "session") == 0)
1339 		success = session_input_channel_req(c, rtype);
1340 	if (reply && !(c->flags & CHAN_CLOSE_SENT)) {
1341 		packet_start(success ?
1342 		    SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE);
1343 		packet_put_int(c->remote_id);
1344 		packet_send();
1345 	}
1346 	free(rtype);
1347 	return 0;
1348 }
1349 
1350 static void
1351 server_init_dispatch_20(void)
1352 {
1353 	debug("server_init_dispatch_20");
1354 	dispatch_init(&dispatch_protocol_error);
1355 	dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose);
1356 	dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data);
1357 	dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof);
1358 	dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data);
1359 	dispatch_set(SSH2_MSG_CHANNEL_OPEN, &server_input_channel_open);
1360 	dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
1361 	dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
1362 	dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &server_input_channel_req);
1363 	dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust);
1364 	dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &server_input_global_request);
1365 	/* client_alive */
1366 	dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, &server_input_keep_alive);
1367 	dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &server_input_keep_alive);
1368 	dispatch_set(SSH2_MSG_REQUEST_SUCCESS, &server_input_keep_alive);
1369 	dispatch_set(SSH2_MSG_REQUEST_FAILURE, &server_input_keep_alive);
1370 	/* rekeying */
1371 	dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit);
1372 }
1373 static void
1374 server_init_dispatch_13(void)
1375 {
1376 	debug("server_init_dispatch_13");
1377 	dispatch_init(NULL);
1378 	dispatch_set(SSH_CMSG_EOF, &server_input_eof);
1379 	dispatch_set(SSH_CMSG_STDIN_DATA, &server_input_stdin_data);
1380 	dispatch_set(SSH_CMSG_WINDOW_SIZE, &server_input_window_size);
1381 	dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close);
1382 	dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation);
1383 	dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data);
1384 	dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
1385 	dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
1386 	dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open);
1387 }
1388 static void
1389 server_init_dispatch_15(void)
1390 {
1391 	server_init_dispatch_13();
1392 	debug("server_init_dispatch_15");
1393 	dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof);
1394 	dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_oclose);
1395 }
1396 static void
1397 server_init_dispatch(void)
1398 {
1399 	if (compat20)
1400 		server_init_dispatch_20();
1401 	else if (compat13)
1402 		server_init_dispatch_13();
1403 	else
1404 		server_init_dispatch_15();
1405 }
1406