xref: /dragonfly/crypto/openssh/serverloop.c (revision 6700dd34)
1 /* $OpenBSD: serverloop.c,v 1.184 2016/03/07 19:02:43 djm Exp $ */
2 /*
3  * Author: Tatu Ylonen <ylo@cs.hut.fi>
4  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5  *                    All rights reserved
6  * Server main loop for handling the interactive session.
7  *
8  * As far as I am concerned, the code I have written for this software
9  * can be used freely for any purpose.  Any derived versions of this
10  * software must be clearly marked as such, and if the derived work is
11  * incompatible with the protocol description in the RFC file, it must be
12  * called by a name other than "ssh" or "Secure Shell".
13  *
14  * SSH2 support by Markus Friedl.
15  * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
16  *
17  * Redistribution and use in source and binary forms, with or without
18  * modification, are permitted provided that the following conditions
19  * are met:
20  * 1. Redistributions of source code must retain the above copyright
21  *    notice, this list of conditions and the following disclaimer.
22  * 2. Redistributions in binary form must reproduce the above copyright
23  *    notice, this list of conditions and the following disclaimer in the
24  *    documentation and/or other materials provided with the distribution.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
27  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
28  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
29  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
30  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
31  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
32  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
33  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
34  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
35  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
36  */
37 
38 #include "includes.h"
39 
40 #include <sys/param.h>	/* MIN MAX */
41 #include <sys/types.h>
42 #include <sys/wait.h>
43 #include <sys/socket.h>
44 #ifdef HAVE_SYS_TIME_H
45 # include <sys/time.h>
46 #endif
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 "openbsd-compat/sys-queue.h"
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 long stdin_bytes = 0;	/* Number of bytes written to stdin. */
97 static long stdout_bytes = 0;	/* Number of stdout bytes sent to client. */
98 static long stderr_bytes = 0;	/* Number of stderr bytes sent to client. */
99 static 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  * we write to this pipe if a SIGCHLD is caught in order to avoid
125  * the race between select() and child_terminated
126  */
127 static int notify_pipe[2];
128 static void
129 notify_setup(void)
130 {
131 	if (pipe(notify_pipe) < 0) {
132 		error("pipe(notify_pipe) failed %s", strerror(errno));
133 	} else if ((fcntl(notify_pipe[0], F_SETFD, FD_CLOEXEC) == -1) ||
134 	    (fcntl(notify_pipe[1], F_SETFD, FD_CLOEXEC) == -1)) {
135 		error("fcntl(notify_pipe, F_SETFD) failed %s", strerror(errno));
136 		close(notify_pipe[0]);
137 		close(notify_pipe[1]);
138 	} else {
139 		set_nonblock(notify_pipe[0]);
140 		set_nonblock(notify_pipe[1]);
141 		return;
142 	}
143 	notify_pipe[0] = -1;	/* read end */
144 	notify_pipe[1] = -1;	/* write end */
145 }
146 static void
147 notify_parent(void)
148 {
149 	if (notify_pipe[1] != -1)
150 		(void)write(notify_pipe[1], "", 1);
151 }
152 static void
153 notify_prepare(fd_set *readset)
154 {
155 	if (notify_pipe[0] != -1)
156 		FD_SET(notify_pipe[0], readset);
157 }
158 static void
159 notify_done(fd_set *readset)
160 {
161 	char c;
162 
163 	if (notify_pipe[0] != -1 && FD_ISSET(notify_pipe[0], readset))
164 		while (read(notify_pipe[0], &c, 1) != -1)
165 			debug2("notify_done: reading");
166 }
167 
168 /*ARGSUSED*/
169 static void
170 sigchld_handler(int sig)
171 {
172 	int save_errno = errno;
173 	child_terminated = 1;
174 #ifndef _UNICOS
175 	mysignal(SIGCHLD, sigchld_handler);
176 #endif
177 	notify_parent();
178 	errno = save_errno;
179 }
180 
181 /*ARGSUSED*/
182 static void
183 sigterm_handler(int sig)
184 {
185 	received_sigterm = sig;
186 }
187 
188 /*
189  * Make packets from buffered stderr data, and buffer it for sending
190  * to the client.
191  */
192 static void
193 make_packets_from_stderr_data(void)
194 {
195 	u_int len;
196 
197 	/* Send buffered stderr data to the client. */
198 	while (buffer_len(&stderr_buffer) > 0 &&
199 	    packet_not_very_much_data_to_write()) {
200 		len = buffer_len(&stderr_buffer);
201 		if (packet_is_interactive()) {
202 			if (len > 512)
203 				len = 512;
204 		} else {
205 			/* Keep the packets at reasonable size. */
206 			if (len > packet_get_maxsize())
207 				len = packet_get_maxsize();
208 		}
209 		packet_start(SSH_SMSG_STDERR_DATA);
210 		packet_put_string(buffer_ptr(&stderr_buffer), len);
211 		packet_send();
212 		buffer_consume(&stderr_buffer, len);
213 		stderr_bytes += len;
214 	}
215 }
216 
217 /*
218  * Make packets from buffered stdout data, and buffer it for sending to the
219  * client.
220  */
221 static void
222 make_packets_from_stdout_data(void)
223 {
224 	u_int len;
225 
226 	/* Send buffered stdout data to the client. */
227 	while (buffer_len(&stdout_buffer) > 0 &&
228 	    packet_not_very_much_data_to_write()) {
229 		len = buffer_len(&stdout_buffer);
230 		if (packet_is_interactive()) {
231 			if (len > 512)
232 				len = 512;
233 		} else {
234 			/* Keep the packets at reasonable size. */
235 			if (len > packet_get_maxsize())
236 				len = packet_get_maxsize();
237 		}
238 		packet_start(SSH_SMSG_STDOUT_DATA);
239 		packet_put_string(buffer_ptr(&stdout_buffer), len);
240 		packet_send();
241 		buffer_consume(&stdout_buffer, len);
242 		stdout_bytes += len;
243 	}
244 }
245 
246 static void
247 client_alive_check(void)
248 {
249 	int channel_id;
250 
251 	/* timeout, check to see how many we have had */
252 	if (packet_inc_alive_timeouts() > options.client_alive_count_max) {
253 		logit("Timeout, client not responding.");
254 		cleanup_exit(255);
255 	}
256 
257 	/*
258 	 * send a bogus global/channel request with "wantreply",
259 	 * we should get back a failure
260 	 */
261 	if ((channel_id = channel_find_open()) == -1) {
262 		packet_start(SSH2_MSG_GLOBAL_REQUEST);
263 		packet_put_cstring("keepalive@openssh.com");
264 		packet_put_char(1);	/* boolean: want reply */
265 	} else {
266 		channel_request_start(channel_id, "keepalive@openssh.com", 1);
267 	}
268 	packet_send();
269 }
270 
271 /*
272  * Sleep in select() until we can do something.  This will initialize the
273  * select masks.  Upon return, the masks will indicate which descriptors
274  * have data or can accept data.  Optionally, a maximum time can be specified
275  * for the duration of the wait (0 = infinite).
276  */
277 static void
278 wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
279     u_int *nallocp, u_int64_t max_time_ms)
280 {
281 	struct timeval tv, *tvp;
282 	int ret;
283 	time_t minwait_secs = 0;
284 	int client_alive_scheduled = 0;
285 	int program_alive_scheduled = 0;
286 
287 	/* Allocate and update select() masks for channel descriptors. */
288 	channel_prepare_select(readsetp, writesetp, maxfdp, nallocp,
289 	    &minwait_secs, 0);
290 
291 	/* XXX need proper deadline system for rekey/client alive */
292 	if (minwait_secs != 0)
293 		max_time_ms = MIN(max_time_ms, (u_int)minwait_secs * 1000);
294 
295 	/*
296 	 * if using client_alive, set the max timeout accordingly,
297 	 * and indicate that this particular timeout was for client
298 	 * alive by setting the client_alive_scheduled flag.
299 	 *
300 	 * this could be randomized somewhat to make traffic
301 	 * analysis more difficult, but we're not doing it yet.
302 	 */
303 	if (compat20 && options.client_alive_interval) {
304 		uint64_t keepalive_ms =
305 		    (uint64_t)options.client_alive_interval * 1000;
306 
307 		client_alive_scheduled = 1;
308 		if (max_time_ms == 0 || max_time_ms > keepalive_ms)
309 			max_time_ms = keepalive_ms;
310 	}
311 
312 	if (compat20) {
313 #if 0
314 		/* wrong: bad condition XXX */
315 		if (channel_not_very_much_buffered_data())
316 #endif
317 		FD_SET(connection_in, *readsetp);
318 	} else {
319 		/*
320 		 * Read packets from the client unless we have too much
321 		 * buffered stdin or channel data.
322 		 */
323 		if (buffer_len(&stdin_buffer) < buffer_high &&
324 		    channel_not_very_much_buffered_data())
325 			FD_SET(connection_in, *readsetp);
326 		/*
327 		 * If there is not too much data already buffered going to
328 		 * the client, try to get some more data from the program.
329 		 */
330 		if (packet_not_very_much_data_to_write()) {
331 			program_alive_scheduled = child_terminated;
332 			if (!fdout_eof)
333 				FD_SET(fdout, *readsetp);
334 			if (!fderr_eof)
335 				FD_SET(fderr, *readsetp);
336 		}
337 		/*
338 		 * If we have buffered data, try to write some of that data
339 		 * to the program.
340 		 */
341 		if (fdin != -1 && buffer_len(&stdin_buffer) > 0)
342 			FD_SET(fdin, *writesetp);
343 	}
344 	notify_prepare(*readsetp);
345 
346 	/*
347 	 * If we have buffered packet data going to the client, mark that
348 	 * descriptor.
349 	 */
350 	if (packet_have_data_to_write())
351 		FD_SET(connection_out, *writesetp);
352 
353 	/*
354 	 * If child has terminated and there is enough buffer space to read
355 	 * from it, then read as much as is available and exit.
356 	 */
357 	if (child_terminated && packet_not_very_much_data_to_write())
358 		if (max_time_ms == 0 || client_alive_scheduled)
359 			max_time_ms = 100;
360 
361 	if (max_time_ms == 0)
362 		tvp = NULL;
363 	else {
364 		tv.tv_sec = max_time_ms / 1000;
365 		tv.tv_usec = 1000 * (max_time_ms % 1000);
366 		tvp = &tv;
367 	}
368 
369 	/* Wait for something to happen, or the timeout to expire. */
370 	ret = select((*maxfdp)+1, *readsetp, *writesetp, NULL, tvp);
371 
372 	if (ret == -1) {
373 		memset(*readsetp, 0, *nallocp);
374 		memset(*writesetp, 0, *nallocp);
375 		if (errno != EINTR)
376 			error("select: %.100s", strerror(errno));
377 	} else {
378 		if (ret == 0 && client_alive_scheduled)
379 			client_alive_check();
380 		if (!compat20 && program_alive_scheduled && fdin_is_tty) {
381 			if (!fdout_eof)
382 				FD_SET(fdout, *readsetp);
383 			if (!fderr_eof)
384 				FD_SET(fderr, *readsetp);
385 		}
386 	}
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 			    errno != EWOULDBLOCK) {
415 				verbose("Read error from remote host "
416 				    "%.100s port %d: %.100s",
417 				    ssh_remote_ipaddr(ssh),
418 				    ssh_remote_port(ssh), strerror(errno));
419 				cleanup_exit(255);
420 			}
421 		} else {
422 			/* Buffer any received data. */
423 			packet_process_incoming(buf, 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 		errno = 0;
432 		len = read(fdout, buf, sizeof(buf));
433 		if (len < 0 && (errno == EINTR || ((errno == EAGAIN ||
434 		    errno == EWOULDBLOCK) && !child_terminated))) {
435 			/* do nothing */
436 #ifndef PTY_ZEROREAD
437 		} else if (len <= 0) {
438 #else
439 		} else if ((!isatty(fdout) && len <= 0) ||
440 		    (isatty(fdout) && (len < 0 || (len == 0 && errno != 0)))) {
441 #endif
442 			fdout_eof = 1;
443 		} else {
444 			buffer_append(&stdout_buffer, buf, len);
445 			fdout_bytes += len;
446 		}
447 	}
448 	/* Read and buffer any available stderr data from the program. */
449 	if (!fderr_eof && FD_ISSET(fderr, readset)) {
450 		errno = 0;
451 		len = read(fderr, buf, sizeof(buf));
452 		if (len < 0 && (errno == EINTR || ((errno == EAGAIN ||
453 		    errno == EWOULDBLOCK) && !child_terminated))) {
454 			/* do nothing */
455 #ifndef PTY_ZEROREAD
456 		} else if (len <= 0) {
457 #else
458 		} else if ((!isatty(fderr) && len <= 0) ||
459 		    (isatty(fderr) && (len < 0 || (len == 0 && errno != 0)))) {
460 #endif
461 			fderr_eof = 1;
462 		} else {
463 			buffer_append(&stderr_buffer, buf, len);
464 		}
465 	}
466 }
467 
468 /*
469  * Sends data from internal buffers to client program stdin.
470  */
471 static void
472 process_output(fd_set *writeset)
473 {
474 	struct termios tio;
475 	u_char *data;
476 	u_int dlen;
477 	int len;
478 
479 	/* Write buffered data to program stdin. */
480 	if (!compat20 && fdin != -1 && FD_ISSET(fdin, writeset)) {
481 		data = buffer_ptr(&stdin_buffer);
482 		dlen = buffer_len(&stdin_buffer);
483 		len = write(fdin, data, dlen);
484 		if (len < 0 &&
485 		    (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK)) {
486 			/* do nothing */
487 		} else if (len <= 0) {
488 			if (fdin != fdout)
489 				close(fdin);
490 			else
491 				shutdown(fdin, SHUT_WR); /* We will no longer send. */
492 			fdin = -1;
493 		} else {
494 			/* Successful write. */
495 			if (fdin_is_tty && dlen >= 1 && data[0] != '\r' &&
496 			    tcgetattr(fdin, &tio) == 0 &&
497 			    !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
498 				/*
499 				 * Simulate echo to reduce the impact of
500 				 * traffic analysis
501 				 */
502 				packet_send_ignore(len);
503 				packet_send();
504 			}
505 			/* Consume the data from the buffer. */
506 			buffer_consume(&stdin_buffer, len);
507 			/* Update the count of bytes written to the program. */
508 			stdin_bytes += len;
509 		}
510 	}
511 	/* Send any buffered packet data to the client. */
512 	if (FD_ISSET(connection_out, writeset))
513 		packet_write_poll();
514 }
515 
516 /*
517  * Wait until all buffered output has been sent to the client.
518  * This is used when the program terminates.
519  */
520 static void
521 drain_output(void)
522 {
523 	/* Send any buffered stdout data to the client. */
524 	if (buffer_len(&stdout_buffer) > 0) {
525 		packet_start(SSH_SMSG_STDOUT_DATA);
526 		packet_put_string(buffer_ptr(&stdout_buffer),
527 				  buffer_len(&stdout_buffer));
528 		packet_send();
529 		/* Update the count of sent bytes. */
530 		stdout_bytes += buffer_len(&stdout_buffer);
531 	}
532 	/* Send any buffered stderr data to the client. */
533 	if (buffer_len(&stderr_buffer) > 0) {
534 		packet_start(SSH_SMSG_STDERR_DATA);
535 		packet_put_string(buffer_ptr(&stderr_buffer),
536 				  buffer_len(&stderr_buffer));
537 		packet_send();
538 		/* Update the count of sent bytes. */
539 		stderr_bytes += buffer_len(&stderr_buffer);
540 	}
541 	/* Wait until all buffered data has been written to the client. */
542 	packet_write_wait();
543 }
544 
545 static void
546 process_buffered_input_packets(void)
547 {
548 	dispatch_run(DISPATCH_NONBLOCK, NULL, active_state);
549 }
550 
551 /*
552  * Performs the interactive session.  This handles data transmission between
553  * the client and the program.  Note that the notion of stdin, stdout, and
554  * stderr in this function is sort of reversed: this function writes to
555  * stdin (of the child program), and reads from stdout and stderr (of the
556  * child program).
557  */
558 void
559 server_loop(pid_t pid, int fdin_arg, int fdout_arg, int fderr_arg)
560 {
561 	fd_set *readset = NULL, *writeset = NULL;
562 	int max_fd = 0;
563 	u_int nalloc = 0;
564 	int wait_status;	/* Status returned by wait(). */
565 	pid_t wait_pid;		/* pid returned by wait(). */
566 	int waiting_termination = 0;	/* Have displayed waiting close message. */
567 	u_int64_t max_time_milliseconds;
568 	u_int previous_stdout_buffer_bytes;
569 	u_int stdout_buffer_bytes;
570 	int type;
571 
572 	debug("Entering interactive session.");
573 
574 	/* Initialize the SIGCHLD kludge. */
575 	child_terminated = 0;
576 	mysignal(SIGCHLD, sigchld_handler);
577 
578 	if (!use_privsep) {
579 		signal(SIGTERM, sigterm_handler);
580 		signal(SIGINT, sigterm_handler);
581 		signal(SIGQUIT, sigterm_handler);
582 	}
583 
584 	/* Initialize our global variables. */
585 	fdin = fdin_arg;
586 	fdout = fdout_arg;
587 	fderr = fderr_arg;
588 
589 	/* nonblocking IO */
590 	set_nonblock(fdin);
591 	set_nonblock(fdout);
592 	/* we don't have stderr for interactive terminal sessions, see below */
593 	if (fderr != -1)
594 		set_nonblock(fderr);
595 
596 	if (!(datafellows & SSH_BUG_IGNOREMSG) && isatty(fdin))
597 		fdin_is_tty = 1;
598 
599 	connection_in = packet_get_connection_in();
600 	connection_out = packet_get_connection_out();
601 
602 	notify_setup();
603 
604 	previous_stdout_buffer_bytes = 0;
605 
606 	/* Set approximate I/O buffer size. */
607 	if (packet_is_interactive())
608 		buffer_high = 4096;
609 	else
610 		buffer_high = 64 * 1024;
611 
612 #if 0
613 	/* Initialize max_fd to the maximum of the known file descriptors. */
614 	max_fd = MAX(connection_in, connection_out);
615 	max_fd = MAX(max_fd, fdin);
616 	max_fd = MAX(max_fd, fdout);
617 	if (fderr != -1)
618 		max_fd = MAX(max_fd, fderr);
619 #endif
620 
621 	/* Initialize Initialize buffers. */
622 	buffer_init(&stdin_buffer);
623 	buffer_init(&stdout_buffer);
624 	buffer_init(&stderr_buffer);
625 
626 	/*
627 	 * If we have no separate fderr (which is the case when we have a pty
628 	 * - there we cannot make difference between data sent to stdout and
629 	 * stderr), indicate that we have seen an EOF from stderr.  This way
630 	 * we don't need to check the descriptor everywhere.
631 	 */
632 	if (fderr == -1)
633 		fderr_eof = 1;
634 
635 	server_init_dispatch();
636 
637 	/* Main loop of the server for the interactive session mode. */
638 	for (;;) {
639 
640 		/* Process buffered packets from the client. */
641 		process_buffered_input_packets();
642 
643 		/*
644 		 * If we have received eof, and there is no more pending
645 		 * input data, cause a real eof by closing fdin.
646 		 */
647 		if (stdin_eof && fdin != -1 && buffer_len(&stdin_buffer) == 0) {
648 			if (fdin != fdout)
649 				close(fdin);
650 			else
651 				shutdown(fdin, SHUT_WR); /* We will no longer send. */
652 			fdin = -1;
653 		}
654 		/* Make packets from buffered stderr data to send to the client. */
655 		make_packets_from_stderr_data();
656 
657 		/*
658 		 * Make packets from buffered stdout data to send to the
659 		 * client. If there is very little to send, this arranges to
660 		 * not send them now, but to wait a short while to see if we
661 		 * are getting more data. This is necessary, as some systems
662 		 * wake up readers from a pty after each separate character.
663 		 */
664 		max_time_milliseconds = 0;
665 		stdout_buffer_bytes = buffer_len(&stdout_buffer);
666 		if (stdout_buffer_bytes != 0 && stdout_buffer_bytes < 256 &&
667 		    stdout_buffer_bytes != previous_stdout_buffer_bytes) {
668 			/* try again after a while */
669 			max_time_milliseconds = 10;
670 		} else {
671 			/* Send it now. */
672 			make_packets_from_stdout_data();
673 		}
674 		previous_stdout_buffer_bytes = buffer_len(&stdout_buffer);
675 
676 		/* Send channel data to the client. */
677 		if (packet_not_very_much_data_to_write())
678 			channel_output_poll();
679 
680 		/*
681 		 * Bail out of the loop if the program has closed its output
682 		 * descriptors, and we have no more data to send to the
683 		 * client, and there is no pending buffered data.
684 		 */
685 		if (fdout_eof && fderr_eof && !packet_have_data_to_write() &&
686 		    buffer_len(&stdout_buffer) == 0 && buffer_len(&stderr_buffer) == 0) {
687 			if (!channel_still_open())
688 				break;
689 			if (!waiting_termination) {
690 				const char *s = "Waiting for forwarded connections to terminate...\r\n";
691 				char *cp;
692 				waiting_termination = 1;
693 				buffer_append(&stderr_buffer, s, strlen(s));
694 
695 				/* Display list of open channels. */
696 				cp = channel_open_message();
697 				buffer_append(&stderr_buffer, cp, strlen(cp));
698 				free(cp);
699 			}
700 		}
701 		max_fd = MAX(connection_in, connection_out);
702 		max_fd = MAX(max_fd, fdin);
703 		max_fd = MAX(max_fd, fdout);
704 		max_fd = MAX(max_fd, fderr);
705 		max_fd = MAX(max_fd, notify_pipe[0]);
706 
707 		/* Sleep in select() until we can do something. */
708 		wait_until_can_do_something(&readset, &writeset, &max_fd,
709 		    &nalloc, max_time_milliseconds);
710 
711 		if (received_sigterm) {
712 			logit("Exiting on signal %d", (int)received_sigterm);
713 			/* Clean up sessions, utmp, etc. */
714 			cleanup_exit(255);
715 		}
716 
717 		/* Process any channel events. */
718 		channel_after_select(readset, writeset);
719 
720 		/* Process input from the client and from program stdout/stderr. */
721 		process_input(readset);
722 
723 		/* Process output to the client and to program stdin. */
724 		process_output(writeset);
725 	}
726 	free(readset);
727 	free(writeset);
728 
729 	/* Cleanup and termination code. */
730 
731 	/* Wait until all output has been sent to the client. */
732 	drain_output();
733 
734 	debug("End of interactive session; stdin %ld, stdout (read %ld, sent %ld), stderr %ld bytes.",
735 	    stdin_bytes, fdout_bytes, stdout_bytes, stderr_bytes);
736 
737 	/* Free and clear the buffers. */
738 	buffer_free(&stdin_buffer);
739 	buffer_free(&stdout_buffer);
740 	buffer_free(&stderr_buffer);
741 
742 	/* Close the file descriptors. */
743 	if (fdout != -1)
744 		close(fdout);
745 	fdout = -1;
746 	fdout_eof = 1;
747 	if (fderr != -1)
748 		close(fderr);
749 	fderr = -1;
750 	fderr_eof = 1;
751 	if (fdin != -1)
752 		close(fdin);
753 	fdin = -1;
754 
755 	channel_free_all();
756 
757 	/* We no longer want our SIGCHLD handler to be called. */
758 	mysignal(SIGCHLD, SIG_DFL);
759 
760 	while ((wait_pid = waitpid(-1, &wait_status, 0)) < 0)
761 		if (errno != EINTR)
762 			packet_disconnect("wait: %.100s", strerror(errno));
763 	if (wait_pid != pid)
764 		error("Strange, wait returned pid %ld, expected %ld",
765 		    (long)wait_pid, (long)pid);
766 
767 	/* Check if it exited normally. */
768 	if (WIFEXITED(wait_status)) {
769 		/* Yes, normal exit.  Get exit status and send it to the client. */
770 		debug("Command exited with status %d.", WEXITSTATUS(wait_status));
771 		packet_start(SSH_SMSG_EXITSTATUS);
772 		packet_put_int(WEXITSTATUS(wait_status));
773 		packet_send();
774 		packet_write_wait();
775 
776 		/*
777 		 * Wait for exit confirmation.  Note that there might be
778 		 * other packets coming before it; however, the program has
779 		 * already died so we just ignore them.  The client is
780 		 * supposed to respond with the confirmation when it receives
781 		 * the exit status.
782 		 */
783 		do {
784 			type = packet_read();
785 		}
786 		while (type != SSH_CMSG_EXIT_CONFIRMATION);
787 
788 		debug("Received exit confirmation.");
789 		return;
790 	}
791 	/* Check if the program terminated due to a signal. */
792 	if (WIFSIGNALED(wait_status))
793 		packet_disconnect("Command terminated on signal %d.",
794 				  WTERMSIG(wait_status));
795 
796 	/* Some weird exit cause.  Just exit. */
797 	packet_disconnect("wait returned status %04x.", wait_status);
798 	/* NOTREACHED */
799 }
800 
801 static void
802 collect_children(void)
803 {
804 	pid_t pid;
805 	sigset_t oset, nset;
806 	int status;
807 
808 	/* block SIGCHLD while we check for dead children */
809 	sigemptyset(&nset);
810 	sigaddset(&nset, SIGCHLD);
811 	sigprocmask(SIG_BLOCK, &nset, &oset);
812 	if (child_terminated) {
813 		debug("Received SIGCHLD.");
814 		while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
815 		    (pid < 0 && errno == EINTR))
816 			if (pid > 0)
817 				session_close_by_pid(pid, status);
818 		child_terminated = 0;
819 	}
820 	sigprocmask(SIG_SETMASK, &oset, NULL);
821 }
822 
823 void
824 server_loop2(Authctxt *authctxt)
825 {
826 	fd_set *readset = NULL, *writeset = NULL;
827 	int max_fd;
828 	u_int nalloc = 0;
829 	u_int64_t rekey_timeout_ms = 0;
830 
831 	debug("Entering interactive session for SSH2.");
832 
833 	mysignal(SIGCHLD, sigchld_handler);
834 	child_terminated = 0;
835 	connection_in = packet_get_connection_in();
836 	connection_out = packet_get_connection_out();
837 
838 	if (!use_privsep) {
839 		signal(SIGTERM, sigterm_handler);
840 		signal(SIGINT, sigterm_handler);
841 		signal(SIGQUIT, sigterm_handler);
842 	}
843 
844 	notify_setup();
845 
846 	max_fd = MAX(connection_in, connection_out);
847 	max_fd = MAX(max_fd, notify_pipe[0]);
848 
849 	server_init_dispatch();
850 
851 	for (;;) {
852 		process_buffered_input_packets();
853 
854 		if (!ssh_packet_is_rekeying(active_state) &&
855 		    packet_not_very_much_data_to_write())
856 			channel_output_poll();
857 		if (options.rekey_interval > 0 && compat20 &&
858 		    !ssh_packet_is_rekeying(active_state))
859 			rekey_timeout_ms = packet_get_rekey_timeout() * 1000;
860 		else
861 			rekey_timeout_ms = 0;
862 
863 		wait_until_can_do_something(&readset, &writeset, &max_fd,
864 		    &nalloc, rekey_timeout_ms);
865 
866 		if (received_sigterm) {
867 			logit("Exiting on signal %d", (int)received_sigterm);
868 			/* Clean up sessions, utmp, etc. */
869 			cleanup_exit(255);
870 		}
871 
872 		collect_children();
873 		if (!ssh_packet_is_rekeying(active_state))
874 			channel_after_select(readset, writeset);
875 		process_input(readset);
876 		if (connection_closed)
877 			break;
878 		process_output(writeset);
879 	}
880 	collect_children();
881 
882 	free(readset);
883 	free(writeset);
884 
885 	/* free all channels, no more reads and writes */
886 	channel_free_all();
887 
888 	/* free remaining sessions, e.g. remove wtmp entries */
889 	session_destroy_all(NULL);
890 }
891 
892 static int
893 server_input_keep_alive(int type, u_int32_t seq, void *ctxt)
894 {
895 	debug("Got %d/%u for keepalive", type, seq);
896 	/*
897 	 * reset timeout, since we got a sane answer from the client.
898 	 * even if this was generated by something other than
899 	 * the bogus CHANNEL_REQUEST we send for keepalives.
900 	 */
901 	packet_set_alive_timeouts(0);
902 	return 0;
903 }
904 
905 static int
906 server_input_stdin_data(int type, u_int32_t seq, void *ctxt)
907 {
908 	char *data;
909 	u_int data_len;
910 
911 	/* Stdin data from the client.  Append it to the buffer. */
912 	/* Ignore any data if the client has closed stdin. */
913 	if (fdin == -1)
914 		return 0;
915 	data = packet_get_string(&data_len);
916 	packet_check_eom();
917 	buffer_append(&stdin_buffer, data, data_len);
918 	explicit_bzero(data, data_len);
919 	free(data);
920 	return 0;
921 }
922 
923 static int
924 server_input_eof(int type, u_int32_t seq, void *ctxt)
925 {
926 	/*
927 	 * Eof from the client.  The stdin descriptor to the
928 	 * program will be closed when all buffered data has
929 	 * drained.
930 	 */
931 	debug("EOF received for stdin.");
932 	packet_check_eom();
933 	stdin_eof = 1;
934 	return 0;
935 }
936 
937 static int
938 server_input_window_size(int type, u_int32_t seq, void *ctxt)
939 {
940 	u_int row = packet_get_int();
941 	u_int col = packet_get_int();
942 	u_int xpixel = packet_get_int();
943 	u_int ypixel = packet_get_int();
944 
945 	debug("Window change received.");
946 	packet_check_eom();
947 	if (fdin != -1)
948 		pty_change_window_size(fdin, row, col, xpixel, ypixel);
949 	return 0;
950 }
951 
952 static Channel *
953 server_request_direct_tcpip(void)
954 {
955 	Channel *c = NULL;
956 	char *target, *originator;
957 	u_short target_port, originator_port;
958 
959 	target = packet_get_string(NULL);
960 	target_port = packet_get_int();
961 	originator = packet_get_string(NULL);
962 	originator_port = packet_get_int();
963 	packet_check_eom();
964 
965 	debug("server_request_direct_tcpip: originator %s port %d, target %s "
966 	    "port %d", originator, originator_port, target, target_port);
967 
968 	/* XXX fine grained permissions */
969 	if ((options.allow_tcp_forwarding & FORWARD_LOCAL) != 0 &&
970 	    !no_port_forwarding_flag) {
971 		c = channel_connect_to_port(target, target_port,
972 		    "direct-tcpip", "direct-tcpip");
973 	} else {
974 		logit("refused local port forward: "
975 		    "originator %s port %d, target %s port %d",
976 		    originator, originator_port, target, target_port);
977 	}
978 
979 	free(originator);
980 	free(target);
981 
982 	return c;
983 }
984 
985 static Channel *
986 server_request_direct_streamlocal(void)
987 {
988 	Channel *c = NULL;
989 	char *target, *originator;
990 	u_short originator_port;
991 
992 	target = packet_get_string(NULL);
993 	originator = packet_get_string(NULL);
994 	originator_port = packet_get_int();
995 	packet_check_eom();
996 
997 	debug("server_request_direct_streamlocal: originator %s port %d, target %s",
998 	    originator, originator_port, target);
999 
1000 	/* XXX fine grained permissions */
1001 	if ((options.allow_streamlocal_forwarding & FORWARD_LOCAL) != 0 &&
1002 	    !no_port_forwarding_flag) {
1003 		c = channel_connect_to_path(target,
1004 		    "direct-streamlocal@openssh.com", "direct-streamlocal");
1005 	} else {
1006 		logit("refused streamlocal port forward: "
1007 		    "originator %s port %d, target %s",
1008 		    originator, originator_port, target);
1009 	}
1010 
1011 	free(originator);
1012 	free(target);
1013 
1014 	return c;
1015 }
1016 
1017 static Channel *
1018 server_request_tun(void)
1019 {
1020 	Channel *c = NULL;
1021 	int mode, tun;
1022 	int sock;
1023 
1024 	mode = packet_get_int();
1025 	switch (mode) {
1026 	case SSH_TUNMODE_POINTOPOINT:
1027 	case SSH_TUNMODE_ETHERNET:
1028 		break;
1029 	default:
1030 		packet_send_debug("Unsupported tunnel device mode.");
1031 		return NULL;
1032 	}
1033 	if ((options.permit_tun & mode) == 0) {
1034 		packet_send_debug("Server has rejected tunnel device "
1035 		    "forwarding");
1036 		return NULL;
1037 	}
1038 
1039 	tun = packet_get_int();
1040 	if (forced_tun_device != -1) {
1041 		if (tun != SSH_TUNID_ANY && forced_tun_device != tun)
1042 			goto done;
1043 		tun = forced_tun_device;
1044 	}
1045 	sock = tun_open(tun, mode);
1046 	if (sock < 0)
1047 		goto done;
1048 	c = channel_new("tun", SSH_CHANNEL_OPEN, sock, sock, -1,
1049 	    CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1);
1050 	c->datagram = 1;
1051 #if defined(SSH_TUN_FILTER)
1052 	if (mode == SSH_TUNMODE_POINTOPOINT)
1053 		channel_register_filter(c->self, sys_tun_infilter,
1054 		    sys_tun_outfilter, NULL, NULL);
1055 #endif
1056 
1057  done:
1058 	if (c == NULL)
1059 		packet_send_debug("Failed to open the tunnel device.");
1060 	return c;
1061 }
1062 
1063 static Channel *
1064 server_request_session(void)
1065 {
1066 	Channel *c;
1067 
1068 	debug("input_session_request");
1069 	packet_check_eom();
1070 
1071 	if (no_more_sessions) {
1072 		packet_disconnect("Possible attack: attempt to open a session "
1073 		    "after additional sessions disabled");
1074 	}
1075 
1076 	/*
1077 	 * A server session has no fd to read or write until a
1078 	 * CHANNEL_REQUEST for a shell is made, so we set the type to
1079 	 * SSH_CHANNEL_LARVAL.  Additionally, a callback for handling all
1080 	 * CHANNEL_REQUEST messages is registered.
1081 	 */
1082 	c = channel_new("session", SSH_CHANNEL_LARVAL,
1083 	    -1, -1, -1, /*window size*/0, CHAN_SES_PACKET_DEFAULT,
1084 	    0, "server-session", 1);
1085 	if (session_open(the_authctxt, c->self) != 1) {
1086 		debug("session open failed, free channel %d", c->self);
1087 		channel_free(c);
1088 		return NULL;
1089 	}
1090 	channel_register_cleanup(c->self, session_close_by_channel, 0);
1091 	return c;
1092 }
1093 
1094 static int
1095 server_input_channel_open(int type, u_int32_t seq, void *ctxt)
1096 {
1097 	Channel *c = NULL;
1098 	char *ctype;
1099 	int rchan;
1100 	u_int rmaxpack, rwindow, len;
1101 
1102 	ctype = packet_get_string(&len);
1103 	rchan = packet_get_int();
1104 	rwindow = packet_get_int();
1105 	rmaxpack = packet_get_int();
1106 
1107 	debug("server_input_channel_open: ctype %s rchan %d win %d max %d",
1108 	    ctype, rchan, rwindow, rmaxpack);
1109 
1110 	if (strcmp(ctype, "session") == 0) {
1111 		c = server_request_session();
1112 	} else if (strcmp(ctype, "direct-tcpip") == 0) {
1113 		c = server_request_direct_tcpip();
1114 	} else if (strcmp(ctype, "direct-streamlocal@openssh.com") == 0) {
1115 		c = server_request_direct_streamlocal();
1116 	} else if (strcmp(ctype, "tun@openssh.com") == 0) {
1117 		c = server_request_tun();
1118 	}
1119 	if (c != NULL) {
1120 		debug("server_input_channel_open: confirm %s", ctype);
1121 		c->remote_id = rchan;
1122 		c->remote_window = rwindow;
1123 		c->remote_maxpacket = rmaxpack;
1124 		if (c->type != SSH_CHANNEL_CONNECTING) {
1125 			packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1126 			packet_put_int(c->remote_id);
1127 			packet_put_int(c->self);
1128 			packet_put_int(c->local_window);
1129 			packet_put_int(c->local_maxpacket);
1130 			packet_send();
1131 		}
1132 	} else {
1133 		debug("server_input_channel_open: failure %s", ctype);
1134 		packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1135 		packet_put_int(rchan);
1136 		packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED);
1137 		if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1138 			packet_put_cstring("open failed");
1139 			packet_put_cstring("");
1140 		}
1141 		packet_send();
1142 	}
1143 	free(ctype);
1144 	return 0;
1145 }
1146 
1147 static int
1148 server_input_hostkeys_prove(struct sshbuf **respp)
1149 {
1150 	struct ssh *ssh = active_state; /* XXX */
1151 	struct sshbuf *resp = NULL;
1152 	struct sshbuf *sigbuf = NULL;
1153 	struct sshkey *key = NULL, *key_pub = NULL, *key_prv = NULL;
1154 	int r, ndx, success = 0;
1155 	const u_char *blob;
1156 	u_char *sig = 0;
1157 	size_t blen, slen;
1158 
1159 	if ((resp = sshbuf_new()) == NULL || (sigbuf = sshbuf_new()) == NULL)
1160 		fatal("%s: sshbuf_new", __func__);
1161 
1162 	while (ssh_packet_remaining(ssh) > 0) {
1163 		sshkey_free(key);
1164 		key = NULL;
1165 		if ((r = sshpkt_get_string_direct(ssh, &blob, &blen)) != 0 ||
1166 		    (r = sshkey_from_blob(blob, blen, &key)) != 0) {
1167 			error("%s: couldn't parse key: %s",
1168 			    __func__, ssh_err(r));
1169 			goto out;
1170 		}
1171 		/*
1172 		 * Better check that this is actually one of our hostkeys
1173 		 * before attempting to sign anything with it.
1174 		 */
1175 		if ((ndx = ssh->kex->host_key_index(key, 1, ssh)) == -1) {
1176 			error("%s: unknown host %s key",
1177 			    __func__, sshkey_type(key));
1178 			goto out;
1179 		}
1180 		/*
1181 		 * XXX refactor: make kex->sign just use an index rather
1182 		 * than passing in public and private keys
1183 		 */
1184 		if ((key_prv = get_hostkey_by_index(ndx)) == NULL &&
1185 		    (key_pub = get_hostkey_public_by_index(ndx, ssh)) == NULL) {
1186 			error("%s: can't retrieve hostkey %d", __func__, ndx);
1187 			goto out;
1188 		}
1189 		sshbuf_reset(sigbuf);
1190 		free(sig);
1191 		sig = NULL;
1192 		if ((r = sshbuf_put_cstring(sigbuf,
1193 		    "hostkeys-prove-00@openssh.com")) != 0 ||
1194 		    (r = sshbuf_put_string(sigbuf,
1195 		    ssh->kex->session_id, ssh->kex->session_id_len)) != 0 ||
1196 		    (r = sshkey_puts(key, sigbuf)) != 0 ||
1197 		    (r = ssh->kex->sign(key_prv, key_pub, &sig, &slen,
1198 		    sshbuf_ptr(sigbuf), sshbuf_len(sigbuf), NULL, 0)) != 0 ||
1199 		    (r = sshbuf_put_string(resp, sig, slen)) != 0) {
1200 			error("%s: couldn't prepare signature: %s",
1201 			    __func__, ssh_err(r));
1202 			goto out;
1203 		}
1204 	}
1205 	/* Success */
1206 	*respp = resp;
1207 	resp = NULL; /* don't free it */
1208 	success = 1;
1209  out:
1210 	free(sig);
1211 	sshbuf_free(resp);
1212 	sshbuf_free(sigbuf);
1213 	sshkey_free(key);
1214 	return success;
1215 }
1216 
1217 static int
1218 server_input_global_request(int type, u_int32_t seq, void *ctxt)
1219 {
1220 	char *rtype;
1221 	int want_reply;
1222 	int r, success = 0, allocated_listen_port = 0;
1223 	struct sshbuf *resp = NULL;
1224 
1225 	rtype = packet_get_string(NULL);
1226 	want_reply = packet_get_char();
1227 	debug("server_input_global_request: rtype %s want_reply %d", rtype, want_reply);
1228 
1229 	/* -R style forwarding */
1230 	if (strcmp(rtype, "tcpip-forward") == 0) {
1231 		struct passwd *pw;
1232 		struct Forward fwd;
1233 
1234 		pw = the_authctxt->pw;
1235 		if (pw == NULL || !the_authctxt->valid)
1236 			fatal("server_input_global_request: no/invalid user");
1237 		memset(&fwd, 0, sizeof(fwd));
1238 		fwd.listen_host = packet_get_string(NULL);
1239 		fwd.listen_port = (u_short)packet_get_int();
1240 		debug("server_input_global_request: tcpip-forward listen %s port %d",
1241 		    fwd.listen_host, fwd.listen_port);
1242 
1243 		/* check permissions */
1244 		if ((options.allow_tcp_forwarding & FORWARD_REMOTE) == 0 ||
1245 		    no_port_forwarding_flag ||
1246 		    (!want_reply && fwd.listen_port == 0) ||
1247 		    (fwd.listen_port != 0 && fwd.listen_port < IPPORT_RESERVED &&
1248 		    pw->pw_uid != 0)) {
1249 			success = 0;
1250 			packet_send_debug("Server has disabled port forwarding.");
1251 		} else {
1252 			/* Start listening on the port */
1253 			success = channel_setup_remote_fwd_listener(&fwd,
1254 			    &allocated_listen_port, &options.fwd_opts);
1255 		}
1256 		free(fwd.listen_host);
1257 		if ((resp = sshbuf_new()) == NULL)
1258 			fatal("%s: sshbuf_new", __func__);
1259 		if (allocated_listen_port != 0 &&
1260 		    (r = sshbuf_put_u32(resp, allocated_listen_port)) != 0)
1261 			fatal("%s: sshbuf_put_u32: %s", __func__, ssh_err(r));
1262 	} else if (strcmp(rtype, "cancel-tcpip-forward") == 0) {
1263 		struct Forward fwd;
1264 
1265 		memset(&fwd, 0, sizeof(fwd));
1266 		fwd.listen_host = packet_get_string(NULL);
1267 		fwd.listen_port = (u_short)packet_get_int();
1268 		debug("%s: cancel-tcpip-forward addr %s port %d", __func__,
1269 		    fwd.listen_host, fwd.listen_port);
1270 
1271 		success = channel_cancel_rport_listener(&fwd);
1272 		free(fwd.listen_host);
1273 	} else if (strcmp(rtype, "streamlocal-forward@openssh.com") == 0) {
1274 		struct Forward fwd;
1275 
1276 		memset(&fwd, 0, sizeof(fwd));
1277 		fwd.listen_path = packet_get_string(NULL);
1278 		debug("server_input_global_request: streamlocal-forward listen path %s",
1279 		    fwd.listen_path);
1280 
1281 		/* check permissions */
1282 		if ((options.allow_streamlocal_forwarding & FORWARD_REMOTE) == 0
1283 		    || no_port_forwarding_flag) {
1284 			success = 0;
1285 			packet_send_debug("Server has disabled port forwarding.");
1286 		} else {
1287 			/* Start listening on the socket */
1288 			success = channel_setup_remote_fwd_listener(
1289 			    &fwd, NULL, &options.fwd_opts);
1290 		}
1291 		free(fwd.listen_path);
1292 	} else if (strcmp(rtype, "cancel-streamlocal-forward@openssh.com") == 0) {
1293 		struct Forward fwd;
1294 
1295 		memset(&fwd, 0, sizeof(fwd));
1296 		fwd.listen_path = packet_get_string(NULL);
1297 		debug("%s: cancel-streamlocal-forward path %s", __func__,
1298 		    fwd.listen_path);
1299 
1300 		success = channel_cancel_rport_listener(&fwd);
1301 		free(fwd.listen_path);
1302 	} else if (strcmp(rtype, "no-more-sessions@openssh.com") == 0) {
1303 		no_more_sessions = 1;
1304 		success = 1;
1305 	} else if (strcmp(rtype, "hostkeys-prove-00@openssh.com") == 0) {
1306 		success = server_input_hostkeys_prove(&resp);
1307 	}
1308 	if (want_reply) {
1309 		packet_start(success ?
1310 		    SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE);
1311 		if (success && resp != NULL)
1312 			ssh_packet_put_raw(active_state, sshbuf_ptr(resp),
1313 			    sshbuf_len(resp));
1314 		packet_send();
1315 		packet_write_wait();
1316 	}
1317 	free(rtype);
1318 	sshbuf_free(resp);
1319 	return 0;
1320 }
1321 
1322 static int
1323 server_input_channel_req(int type, u_int32_t seq, void *ctxt)
1324 {
1325 	Channel *c;
1326 	int id, reply, success = 0;
1327 	char *rtype;
1328 
1329 	id = packet_get_int();
1330 	rtype = packet_get_string(NULL);
1331 	reply = packet_get_char();
1332 
1333 	debug("server_input_channel_req: channel %d request %s reply %d",
1334 	    id, rtype, reply);
1335 
1336 	if ((c = channel_lookup(id)) == NULL)
1337 		packet_disconnect("server_input_channel_req: "
1338 		    "unknown channel %d", id);
1339 	if (!strcmp(rtype, "eow@openssh.com")) {
1340 		packet_check_eom();
1341 		chan_rcvd_eow(c);
1342 	} else if ((c->type == SSH_CHANNEL_LARVAL ||
1343 	    c->type == SSH_CHANNEL_OPEN) && strcmp(c->ctype, "session") == 0)
1344 		success = session_input_channel_req(c, rtype);
1345 	if (reply && !(c->flags & CHAN_CLOSE_SENT)) {
1346 		packet_start(success ?
1347 		    SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE);
1348 		packet_put_int(c->remote_id);
1349 		packet_send();
1350 	}
1351 	free(rtype);
1352 	return 0;
1353 }
1354 
1355 static void
1356 server_init_dispatch_20(void)
1357 {
1358 	debug("server_init_dispatch_20");
1359 	dispatch_init(&dispatch_protocol_error);
1360 	dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose);
1361 	dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data);
1362 	dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof);
1363 	dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data);
1364 	dispatch_set(SSH2_MSG_CHANNEL_OPEN, &server_input_channel_open);
1365 	dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
1366 	dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
1367 	dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &server_input_channel_req);
1368 	dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust);
1369 	dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &server_input_global_request);
1370 	/* client_alive */
1371 	dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, &server_input_keep_alive);
1372 	dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &server_input_keep_alive);
1373 	dispatch_set(SSH2_MSG_REQUEST_SUCCESS, &server_input_keep_alive);
1374 	dispatch_set(SSH2_MSG_REQUEST_FAILURE, &server_input_keep_alive);
1375 	/* rekeying */
1376 	dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit);
1377 }
1378 static void
1379 server_init_dispatch_13(void)
1380 {
1381 	debug("server_init_dispatch_13");
1382 	dispatch_init(NULL);
1383 	dispatch_set(SSH_CMSG_EOF, &server_input_eof);
1384 	dispatch_set(SSH_CMSG_STDIN_DATA, &server_input_stdin_data);
1385 	dispatch_set(SSH_CMSG_WINDOW_SIZE, &server_input_window_size);
1386 	dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close);
1387 	dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation);
1388 	dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data);
1389 	dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
1390 	dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
1391 	dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open);
1392 }
1393 static void
1394 server_init_dispatch_15(void)
1395 {
1396 	server_init_dispatch_13();
1397 	debug("server_init_dispatch_15");
1398 	dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof);
1399 	dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_oclose);
1400 }
1401 static void
1402 server_init_dispatch(void)
1403 {
1404 	if (compat20)
1405 		server_init_dispatch_20();
1406 	else if (compat13)
1407 		server_init_dispatch_13();
1408 	else
1409 		server_init_dispatch_15();
1410 }
1411