session.c revision 128460
1/*
2 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
3 *                    All rights reserved
4 *
5 * As far as I am concerned, the code I have written for this software
6 * can be used freely for any purpose.  Any derived versions of this
7 * software must be clearly marked as such, and if the derived work is
8 * incompatible with the protocol description in the RFC file, it must be
9 * called by a name other than "ssh" or "Secure Shell".
10 *
11 * SSH2 support by Markus Friedl.
12 * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
13 *
14 * Redistribution and use in source and binary forms, with or without
15 * modification, are permitted provided that the following conditions
16 * are met:
17 * 1. Redistributions of source code must retain the above copyright
18 *    notice, this list of conditions and the following disclaimer.
19 * 2. Redistributions in binary form must reproduce the above copyright
20 *    notice, this list of conditions and the following disclaimer in the
21 *    documentation and/or other materials provided with the distribution.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
26 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
27 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
28 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
32 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
33 */
34
35#include "includes.h"
36RCSID("$OpenBSD: session.c,v 1.172 2004/01/30 09:48:57 markus Exp $");
37RCSID("$FreeBSD: head/crypto/openssh/session.c 128460 2004-04-20 09:46:41Z des $");
38
39#include "ssh.h"
40#include "ssh1.h"
41#include "ssh2.h"
42#include "xmalloc.h"
43#include "sshpty.h"
44#include "packet.h"
45#include "buffer.h"
46#include "mpaux.h"
47#include "uidswap.h"
48#include "compat.h"
49#include "channels.h"
50#include "bufaux.h"
51#include "auth.h"
52#include "auth-options.h"
53#include "pathnames.h"
54#include "log.h"
55#include "servconf.h"
56#include "sshlogin.h"
57#include "serverloop.h"
58#include "canohost.h"
59#include "session.h"
60#include "monitor_wrap.h"
61
62#if defined(KRB5) && defined(USE_AFS)
63#include <kafs.h>
64#endif
65
66#ifdef GSSAPI
67#include "ssh-gss.h"
68#endif
69
70/* func */
71
72Session *session_new(void);
73void	session_set_fds(Session *, int, int, int);
74void	session_pty_cleanup(Session *);
75void	session_proctitle(Session *);
76int	session_setup_x11fwd(Session *);
77void	do_exec_pty(Session *, const char *);
78void	do_exec_no_pty(Session *, const char *);
79void	do_exec(Session *, const char *);
80void	do_login(Session *, const char *);
81#ifdef LOGIN_NEEDS_UTMPX
82static void	do_pre_login(Session *s);
83#endif
84void	do_child(Session *, const char *);
85void	do_motd(void);
86int	check_quietlogin(Session *, const char *);
87
88static void do_authenticated1(Authctxt *);
89static void do_authenticated2(Authctxt *);
90
91static int session_pty_req(Session *);
92
93/* import */
94extern ServerOptions options;
95extern char *__progname;
96extern int log_stderr;
97extern int debug_flag;
98extern u_int utmp_len;
99extern int startup_pipe;
100extern void destroy_sensitive_data(void);
101extern Buffer loginmsg;
102
103/* original command from peer. */
104const char *original_command = NULL;
105
106/* data */
107#define MAX_SESSIONS 10
108Session	sessions[MAX_SESSIONS];
109
110#ifdef HAVE_LOGIN_CAP
111login_cap_t *lc;
112#endif
113
114static int is_child = 0;
115
116/* Name and directory of socket for authentication agent forwarding. */
117static char *auth_sock_name = NULL;
118static char *auth_sock_dir = NULL;
119
120/* removes the agent forwarding socket */
121
122static void
123auth_sock_cleanup_proc(struct passwd *pw)
124{
125	if (auth_sock_name != NULL) {
126		temporarily_use_uid(pw);
127		unlink(auth_sock_name);
128		rmdir(auth_sock_dir);
129		auth_sock_name = NULL;
130		restore_uid();
131	}
132}
133
134static int
135auth_input_request_forwarding(struct passwd * pw)
136{
137	Channel *nc;
138	int sock;
139	struct sockaddr_un sunaddr;
140
141	if (auth_sock_name != NULL) {
142		error("authentication forwarding requested twice.");
143		return 0;
144	}
145
146	/* Temporarily drop privileged uid for mkdir/bind. */
147	temporarily_use_uid(pw);
148
149	/* Allocate a buffer for the socket name, and format the name. */
150	auth_sock_name = xmalloc(MAXPATHLEN);
151	auth_sock_dir = xmalloc(MAXPATHLEN);
152	strlcpy(auth_sock_dir, "/tmp/ssh-XXXXXXXXXX", MAXPATHLEN);
153
154	/* Create private directory for socket */
155	if (mkdtemp(auth_sock_dir) == NULL) {
156		packet_send_debug("Agent forwarding disabled: "
157		    "mkdtemp() failed: %.100s", strerror(errno));
158		restore_uid();
159		xfree(auth_sock_name);
160		xfree(auth_sock_dir);
161		auth_sock_name = NULL;
162		auth_sock_dir = NULL;
163		return 0;
164	}
165	snprintf(auth_sock_name, MAXPATHLEN, "%s/agent.%ld",
166		 auth_sock_dir, (long) getpid());
167
168	/* Create the socket. */
169	sock = socket(AF_UNIX, SOCK_STREAM, 0);
170	if (sock < 0)
171		packet_disconnect("socket: %.100s", strerror(errno));
172
173	/* Bind it to the name. */
174	memset(&sunaddr, 0, sizeof(sunaddr));
175	sunaddr.sun_family = AF_UNIX;
176	strlcpy(sunaddr.sun_path, auth_sock_name, sizeof(sunaddr.sun_path));
177
178	if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0)
179		packet_disconnect("bind: %.100s", strerror(errno));
180
181	/* Restore the privileged uid. */
182	restore_uid();
183
184	/* Start listening on the socket. */
185	if (listen(sock, SSH_LISTEN_BACKLOG) < 0)
186		packet_disconnect("listen: %.100s", strerror(errno));
187
188	/* Allocate a channel for the authentication agent socket. */
189	nc = channel_new("auth socket",
190	    SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1,
191	    CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
192	    0, "auth socket", 1);
193	strlcpy(nc->path, auth_sock_name, sizeof(nc->path));
194	return 1;
195}
196
197static void
198display_loginmsg(void)
199{
200	if (buffer_len(&loginmsg) > 0) {
201		buffer_append(&loginmsg, "\0", 1);
202		printf("%s\n", (char *)buffer_ptr(&loginmsg));
203		buffer_clear(&loginmsg);
204	}
205	fflush(stdout);
206}
207
208void
209do_authenticated(Authctxt *authctxt)
210{
211	setproctitle("%s", authctxt->pw->pw_name);
212
213	/*
214	 * Cancel the alarm we set to limit the time taken for
215	 * authentication.
216	 */
217	alarm(0);
218	if (startup_pipe != -1) {
219		close(startup_pipe);
220		startup_pipe = -1;
221	}
222	/* setup the channel layer */
223	if (!no_port_forwarding_flag && options.allow_tcp_forwarding)
224		channel_permit_all_opens();
225
226	if (compat20)
227		do_authenticated2(authctxt);
228	else
229		do_authenticated1(authctxt);
230
231	do_cleanup(authctxt);
232}
233
234/*
235 * Prepares for an interactive session.  This is called after the user has
236 * been successfully authenticated.  During this message exchange, pseudo
237 * terminals are allocated, X11, TCP/IP, and authentication agent forwardings
238 * are requested, etc.
239 */
240static void
241do_authenticated1(Authctxt *authctxt)
242{
243	Session *s;
244	char *command;
245	int success, type, screen_flag;
246	int enable_compression_after_reply = 0;
247	u_int proto_len, data_len, dlen, compression_level = 0;
248
249	s = session_new();
250	s->authctxt = authctxt;
251	s->pw = authctxt->pw;
252
253	/*
254	 * We stay in this loop until the client requests to execute a shell
255	 * or a command.
256	 */
257	for (;;) {
258		success = 0;
259
260		/* Get a packet from the client. */
261		type = packet_read();
262
263		/* Process the packet. */
264		switch (type) {
265		case SSH_CMSG_REQUEST_COMPRESSION:
266			compression_level = packet_get_int();
267			packet_check_eom();
268			if (compression_level < 1 || compression_level > 9) {
269				packet_send_debug("Received illegal compression level %d.",
270				    compression_level);
271				break;
272			}
273			if (!options.compression) {
274				debug2("compression disabled");
275				break;
276			}
277			/* Enable compression after we have responded with SUCCESS. */
278			enable_compression_after_reply = 1;
279			success = 1;
280			break;
281
282		case SSH_CMSG_REQUEST_PTY:
283			success = session_pty_req(s);
284			break;
285
286		case SSH_CMSG_X11_REQUEST_FORWARDING:
287			s->auth_proto = packet_get_string(&proto_len);
288			s->auth_data = packet_get_string(&data_len);
289
290			screen_flag = packet_get_protocol_flags() &
291			    SSH_PROTOFLAG_SCREEN_NUMBER;
292			debug2("SSH_PROTOFLAG_SCREEN_NUMBER: %d", screen_flag);
293
294			if (packet_remaining() == 4) {
295				if (!screen_flag)
296					debug2("Buggy client: "
297					    "X11 screen flag missing");
298				s->screen = packet_get_int();
299			} else {
300				s->screen = 0;
301			}
302			packet_check_eom();
303			success = session_setup_x11fwd(s);
304			if (!success) {
305				xfree(s->auth_proto);
306				xfree(s->auth_data);
307				s->auth_proto = NULL;
308				s->auth_data = NULL;
309			}
310			break;
311
312		case SSH_CMSG_AGENT_REQUEST_FORWARDING:
313			if (no_agent_forwarding_flag || compat13) {
314				debug("Authentication agent forwarding not permitted for this authentication.");
315				break;
316			}
317			debug("Received authentication agent forwarding request.");
318			success = auth_input_request_forwarding(s->pw);
319			break;
320
321		case SSH_CMSG_PORT_FORWARD_REQUEST:
322			if (no_port_forwarding_flag) {
323				debug("Port forwarding not permitted for this authentication.");
324				break;
325			}
326			if (!options.allow_tcp_forwarding) {
327				debug("Port forwarding not permitted.");
328				break;
329			}
330			debug("Received TCP/IP port forwarding request.");
331			channel_input_port_forward_request(s->pw->pw_uid == 0, options.gateway_ports);
332			success = 1;
333			break;
334
335		case SSH_CMSG_MAX_PACKET_SIZE:
336			if (packet_set_maxsize(packet_get_int()) > 0)
337				success = 1;
338			break;
339
340		case SSH_CMSG_EXEC_SHELL:
341		case SSH_CMSG_EXEC_CMD:
342			if (type == SSH_CMSG_EXEC_CMD) {
343				command = packet_get_string(&dlen);
344				debug("Exec command '%.500s'", command);
345				do_exec(s, command);
346				xfree(command);
347			} else {
348				do_exec(s, NULL);
349			}
350			packet_check_eom();
351			session_close(s);
352			return;
353
354		default:
355			/*
356			 * Any unknown messages in this phase are ignored,
357			 * and a failure message is returned.
358			 */
359			logit("Unknown packet type received after authentication: %d", type);
360		}
361		packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE);
362		packet_send();
363		packet_write_wait();
364
365		/* Enable compression now that we have replied if appropriate. */
366		if (enable_compression_after_reply) {
367			enable_compression_after_reply = 0;
368			packet_start_compression(compression_level);
369		}
370	}
371}
372
373/*
374 * This is called to fork and execute a command when we have no tty.  This
375 * will call do_child from the child, and server_loop from the parent after
376 * setting up file descriptors and such.
377 */
378void
379do_exec_no_pty(Session *s, const char *command)
380{
381	pid_t pid;
382
383#ifdef USE_PIPES
384	int pin[2], pout[2], perr[2];
385	/* Allocate pipes for communicating with the program. */
386	if (pipe(pin) < 0 || pipe(pout) < 0 || pipe(perr) < 0)
387		packet_disconnect("Could not create pipes: %.100s",
388				  strerror(errno));
389#else /* USE_PIPES */
390	int inout[2], err[2];
391	/* Uses socket pairs to communicate with the program. */
392	if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0 ||
393	    socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0)
394		packet_disconnect("Could not create socket pairs: %.100s",
395				  strerror(errno));
396#endif /* USE_PIPES */
397	if (s == NULL)
398		fatal("do_exec_no_pty: no session");
399
400	session_proctitle(s);
401
402#if defined(USE_PAM)
403	if (options.use_pam && !use_privsep)
404		do_pam_setcred(1);
405#endif /* USE_PAM */
406
407	/* Fork the child. */
408	if ((pid = fork()) == 0) {
409		is_child = 1;
410
411		/* Child.  Reinitialize the log since the pid has changed. */
412		log_init(__progname, options.log_level, options.log_facility, log_stderr);
413
414		/*
415		 * Create a new session and process group since the 4.4BSD
416		 * setlogin() affects the entire process group.
417		 */
418		if (setsid() < 0)
419			error("setsid failed: %.100s", strerror(errno));
420
421#ifdef USE_PIPES
422		/*
423		 * Redirect stdin.  We close the parent side of the socket
424		 * pair, and make the child side the standard input.
425		 */
426		close(pin[1]);
427		if (dup2(pin[0], 0) < 0)
428			perror("dup2 stdin");
429		close(pin[0]);
430
431		/* Redirect stdout. */
432		close(pout[0]);
433		if (dup2(pout[1], 1) < 0)
434			perror("dup2 stdout");
435		close(pout[1]);
436
437		/* Redirect stderr. */
438		close(perr[0]);
439		if (dup2(perr[1], 2) < 0)
440			perror("dup2 stderr");
441		close(perr[1]);
442#else /* USE_PIPES */
443		/*
444		 * Redirect stdin, stdout, and stderr.  Stdin and stdout will
445		 * use the same socket, as some programs (particularly rdist)
446		 * seem to depend on it.
447		 */
448		close(inout[1]);
449		close(err[1]);
450		if (dup2(inout[0], 0) < 0)	/* stdin */
451			perror("dup2 stdin");
452		if (dup2(inout[0], 1) < 0)	/* stdout.  Note: same socket as stdin. */
453			perror("dup2 stdout");
454		if (dup2(err[0], 2) < 0)	/* stderr */
455			perror("dup2 stderr");
456#endif /* USE_PIPES */
457
458#ifdef _UNICOS
459		cray_init_job(s->pw); /* set up cray jid and tmpdir */
460#endif
461
462		/* Do processing for the child (exec command etc). */
463		do_child(s, command);
464		/* NOTREACHED */
465	}
466#ifdef _UNICOS
467	signal(WJSIGNAL, cray_job_termination_handler);
468#endif /* _UNICOS */
469#ifdef HAVE_CYGWIN
470	if (is_winnt)
471		cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
472#endif
473	if (pid < 0)
474		packet_disconnect("fork failed: %.100s", strerror(errno));
475	s->pid = pid;
476	/* Set interactive/non-interactive mode. */
477	packet_set_interactive(s->display != NULL);
478#ifdef USE_PIPES
479	/* We are the parent.  Close the child sides of the pipes. */
480	close(pin[0]);
481	close(pout[1]);
482	close(perr[1]);
483
484	if (compat20) {
485		session_set_fds(s, pin[1], pout[0], s->is_subsystem ? -1 : perr[0]);
486	} else {
487		/* Enter the interactive session. */
488		server_loop(pid, pin[1], pout[0], perr[0]);
489		/* server_loop has closed pin[1], pout[0], and perr[0]. */
490	}
491#else /* USE_PIPES */
492	/* We are the parent.  Close the child sides of the socket pairs. */
493	close(inout[0]);
494	close(err[0]);
495
496	/*
497	 * Clear loginmsg, since it's the child's responsibility to display
498	 * it to the user, otherwise multiple sessions may accumulate
499	 * multiple copies of the login messages.
500	 */
501	buffer_clear(&loginmsg);
502
503	/*
504	 * Enter the interactive session.  Note: server_loop must be able to
505	 * handle the case that fdin and fdout are the same.
506	 */
507	if (compat20) {
508		session_set_fds(s, inout[1], inout[1], s->is_subsystem ? -1 : err[1]);
509	} else {
510		server_loop(pid, inout[1], inout[1], err[1]);
511		/* server_loop has closed inout[1] and err[1]. */
512	}
513#endif /* USE_PIPES */
514}
515
516/*
517 * This is called to fork and execute a command when we have a tty.  This
518 * will call do_child from the child, and server_loop from the parent after
519 * setting up file descriptors, controlling tty, updating wtmp, utmp,
520 * lastlog, and other such operations.
521 */
522void
523do_exec_pty(Session *s, const char *command)
524{
525	int fdout, ptyfd, ttyfd, ptymaster;
526	pid_t pid;
527
528	if (s == NULL)
529		fatal("do_exec_pty: no session");
530	ptyfd = s->ptyfd;
531	ttyfd = s->ttyfd;
532
533#if defined(USE_PAM)
534	if (options.use_pam) {
535		do_pam_set_tty(s->tty);
536		if (!use_privsep)
537			do_pam_setcred(1);
538	}
539#endif
540
541	/* Fork the child. */
542	if ((pid = fork()) == 0) {
543		is_child = 1;
544
545		/* Child.  Reinitialize the log because the pid has changed. */
546		log_init(__progname, options.log_level, options.log_facility, log_stderr);
547		/* Close the master side of the pseudo tty. */
548		close(ptyfd);
549
550		/* Make the pseudo tty our controlling tty. */
551		pty_make_controlling_tty(&ttyfd, s->tty);
552
553		/* Redirect stdin/stdout/stderr from the pseudo tty. */
554		if (dup2(ttyfd, 0) < 0)
555			error("dup2 stdin: %s", strerror(errno));
556		if (dup2(ttyfd, 1) < 0)
557			error("dup2 stdout: %s", strerror(errno));
558		if (dup2(ttyfd, 2) < 0)
559			error("dup2 stderr: %s", strerror(errno));
560
561		/* Close the extra descriptor for the pseudo tty. */
562		close(ttyfd);
563
564		/* record login, etc. similar to login(1) */
565#ifndef HAVE_OSF_SIA
566		if (!(options.use_login && command == NULL)) {
567#ifdef _UNICOS
568			cray_init_job(s->pw); /* set up cray jid and tmpdir */
569#endif /* _UNICOS */
570			do_login(s, command);
571		}
572# ifdef LOGIN_NEEDS_UTMPX
573		else
574			do_pre_login(s);
575# endif
576#endif
577
578		/* Do common processing for the child, such as execing the command. */
579		do_child(s, command);
580		/* NOTREACHED */
581	}
582#ifdef _UNICOS
583	signal(WJSIGNAL, cray_job_termination_handler);
584#endif /* _UNICOS */
585#ifdef HAVE_CYGWIN
586	if (is_winnt)
587		cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
588#endif
589	if (pid < 0)
590		packet_disconnect("fork failed: %.100s", strerror(errno));
591	s->pid = pid;
592
593	/* Parent.  Close the slave side of the pseudo tty. */
594	close(ttyfd);
595
596	/*
597	 * Create another descriptor of the pty master side for use as the
598	 * standard input.  We could use the original descriptor, but this
599	 * simplifies code in server_loop.  The descriptor is bidirectional.
600	 */
601	fdout = dup(ptyfd);
602	if (fdout < 0)
603		packet_disconnect("dup #1 failed: %.100s", strerror(errno));
604
605	/* we keep a reference to the pty master */
606	ptymaster = dup(ptyfd);
607	if (ptymaster < 0)
608		packet_disconnect("dup #2 failed: %.100s", strerror(errno));
609	s->ptymaster = ptymaster;
610
611	/* Enter interactive session. */
612	packet_set_interactive(1);
613	if (compat20) {
614		session_set_fds(s, ptyfd, fdout, -1);
615	} else {
616		server_loop(pid, ptyfd, fdout, -1);
617		/* server_loop _has_ closed ptyfd and fdout. */
618	}
619}
620
621#ifdef LOGIN_NEEDS_UTMPX
622static void
623do_pre_login(Session *s)
624{
625	socklen_t fromlen;
626	struct sockaddr_storage from;
627	pid_t pid = getpid();
628
629	/*
630	 * Get IP address of client. If the connection is not a socket, let
631	 * the address be 0.0.0.0.
632	 */
633	memset(&from, 0, sizeof(from));
634	fromlen = sizeof(from);
635	if (packet_connection_is_on_socket()) {
636		if (getpeername(packet_get_connection_in(),
637		    (struct sockaddr *) & from, &fromlen) < 0) {
638			debug("getpeername: %.100s", strerror(errno));
639			cleanup_exit(255);
640		}
641	}
642
643	record_utmp_only(pid, s->tty, s->pw->pw_name,
644	    get_remote_name_or_ip(utmp_len, options.use_dns),
645	    (struct sockaddr *)&from, fromlen);
646}
647#endif
648
649/*
650 * This is called to fork and execute a command.  If another command is
651 * to be forced, execute that instead.
652 */
653void
654do_exec(Session *s, const char *command)
655{
656	if (forced_command) {
657		original_command = command;
658		command = forced_command;
659		debug("Forced command '%.900s'", command);
660	}
661
662#ifdef GSSAPI
663	if (options.gss_authentication) {
664		temporarily_use_uid(s->pw);
665		ssh_gssapi_storecreds();
666		restore_uid();
667	}
668#endif
669
670	if (s->ttyfd != -1)
671		do_exec_pty(s, command);
672	else
673		do_exec_no_pty(s, command);
674
675	original_command = NULL;
676}
677
678
679/* administrative, login(1)-like work */
680void
681do_login(Session *s, const char *command)
682{
683	char *time_string;
684	socklen_t fromlen;
685	struct sockaddr_storage from;
686	struct passwd * pw = s->pw;
687	pid_t pid = getpid();
688
689	/*
690	 * Get IP address of client. If the connection is not a socket, let
691	 * the address be 0.0.0.0.
692	 */
693	memset(&from, 0, sizeof(from));
694	fromlen = sizeof(from);
695	if (packet_connection_is_on_socket()) {
696		if (getpeername(packet_get_connection_in(),
697		    (struct sockaddr *) & from, &fromlen) < 0) {
698			debug("getpeername: %.100s", strerror(errno));
699			cleanup_exit(255);
700		}
701	}
702
703	/* Record that there was a login on that tty from the remote host. */
704	if (!use_privsep)
705		record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
706		    get_remote_name_or_ip(utmp_len,
707		    options.use_dns),
708		    (struct sockaddr *)&from, fromlen);
709
710#ifdef USE_PAM
711	/*
712	 * If password change is needed, do it now.
713	 * This needs to occur before the ~/.hushlogin check.
714	 */
715	if (options.use_pam && !use_privsep && s->authctxt->force_pwchange) {
716		display_loginmsg();
717		do_pam_chauthtok();
718		s->authctxt->force_pwchange = 0;
719		/* XXX - signal [net] parent to enable forwardings */
720	}
721#endif
722
723	if (check_quietlogin(s, command))
724		return;
725
726	display_loginmsg();
727
728#ifndef NO_SSH_LASTLOG
729	if (options.print_lastlog && s->last_login_time != 0) {
730		time_string = ctime(&s->last_login_time);
731		if (strchr(time_string, '\n'))
732			*strchr(time_string, '\n') = 0;
733		if (strcmp(s->hostname, "") == 0)
734			printf("Last login: %s\r\n", time_string);
735		else
736			printf("Last login: %s from %s\r\n", time_string,
737			    s->hostname);
738	}
739#endif /* NO_SSH_LASTLOG */
740
741	do_motd();
742}
743
744/*
745 * Display the message of the day.
746 */
747void
748do_motd(void)
749{
750	FILE *f;
751	char buf[256];
752#ifdef HAVE_LOGIN_CAP
753	const char *fname;
754#endif
755
756#ifdef HAVE_LOGIN_CAP
757	fname = login_getcapstr(lc, "copyright", NULL, NULL);
758	if (fname != NULL && (f = fopen(fname, "r")) != NULL) {
759		while (fgets(buf, sizeof(buf), f) != NULL)
760			fputs(buf, stdout);
761			fclose(f);
762	} else
763#endif /* HAVE_LOGIN_CAP */
764		(void)printf("%s\n\t%s %s\n",
765	"Copyright (c) 1980, 1983, 1986, 1988, 1990, 1991, 1993, 1994",
766	"The Regents of the University of California. ",
767	"All rights reserved.");
768
769	(void)printf("\n");
770
771	if (options.print_motd) {
772#ifdef HAVE_LOGIN_CAP
773		f = fopen(login_getcapstr(lc, "welcome", "/etc/motd",
774		    "/etc/motd"), "r");
775#else
776		f = fopen("/etc/motd", "r");
777#endif
778		if (f) {
779			while (fgets(buf, sizeof(buf), f))
780				fputs(buf, stdout);
781			fclose(f);
782		}
783	}
784}
785
786
787/*
788 * Check for quiet login, either .hushlogin or command given.
789 */
790int
791check_quietlogin(Session *s, const char *command)
792{
793	char buf[256];
794	struct passwd *pw = s->pw;
795	struct stat st;
796
797	/* Return 1 if .hushlogin exists or a command given. */
798	if (command != NULL)
799		return 1;
800	snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
801#ifdef HAVE_LOGIN_CAP
802	if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
803		return 1;
804#else
805	if (stat(buf, &st) >= 0)
806		return 1;
807#endif
808	return 0;
809}
810
811/*
812 * Sets the value of the given variable in the environment.  If the variable
813 * already exists, its value is overriden.
814 */
815void
816child_set_env(char ***envp, u_int *envsizep, const char *name,
817	const char *value)
818{
819	char **env;
820	u_int envsize;
821	u_int i, namelen;
822
823	/*
824	 * If we're passed an uninitialized list, allocate a single null
825	 * entry before continuing.
826	 */
827	if (*envp == NULL && *envsizep == 0) {
828		*envp = xmalloc(sizeof(char *));
829		*envp[0] = NULL;
830		*envsizep = 1;
831	}
832
833	/*
834	 * Find the slot where the value should be stored.  If the variable
835	 * already exists, we reuse the slot; otherwise we append a new slot
836	 * at the end of the array, expanding if necessary.
837	 */
838	env = *envp;
839	namelen = strlen(name);
840	for (i = 0; env[i]; i++)
841		if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
842			break;
843	if (env[i]) {
844		/* Reuse the slot. */
845		xfree(env[i]);
846	} else {
847		/* New variable.  Expand if necessary. */
848		envsize = *envsizep;
849		if (i >= envsize - 1) {
850			if (envsize >= 1000)
851				fatal("child_set_env: too many env vars");
852			envsize += 50;
853			env = (*envp) = xrealloc(env, envsize * sizeof(char *));
854			*envsizep = envsize;
855		}
856		/* Need to set the NULL pointer at end of array beyond the new slot. */
857		env[i + 1] = NULL;
858	}
859
860	/* Allocate space and format the variable in the appropriate slot. */
861	env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
862	snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
863}
864
865/*
866 * Reads environment variables from the given file and adds/overrides them
867 * into the environment.  If the file does not exist, this does nothing.
868 * Otherwise, it must consist of empty lines, comments (line starts with '#')
869 * and assignments of the form name=value.  No other forms are allowed.
870 */
871static void
872read_environment_file(char ***env, u_int *envsize,
873	const char *filename)
874{
875	FILE *f;
876	char buf[4096];
877	char *cp, *value;
878	u_int lineno = 0;
879
880	f = fopen(filename, "r");
881	if (!f)
882		return;
883
884	while (fgets(buf, sizeof(buf), f)) {
885		if (++lineno > 1000)
886			fatal("Too many lines in environment file %s", filename);
887		for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
888			;
889		if (!*cp || *cp == '#' || *cp == '\n')
890			continue;
891		if (strchr(cp, '\n'))
892			*strchr(cp, '\n') = '\0';
893		value = strchr(cp, '=');
894		if (value == NULL) {
895			fprintf(stderr, "Bad line %u in %.100s\n", lineno,
896			    filename);
897			continue;
898		}
899		/*
900		 * Replace the equals sign by nul, and advance value to
901		 * the value string.
902		 */
903		*value = '\0';
904		value++;
905		child_set_env(env, envsize, cp, value);
906	}
907	fclose(f);
908}
909
910#ifdef HAVE_ETC_DEFAULT_LOGIN
911/*
912 * Return named variable from specified environment, or NULL if not present.
913 */
914static char *
915child_get_env(char **env, const char *name)
916{
917	int i;
918	size_t len;
919
920	len = strlen(name);
921	for (i=0; env[i] != NULL; i++)
922		if (strncmp(name, env[i], len) == 0 && env[i][len] == '=')
923			return(env[i] + len + 1);
924	return NULL;
925}
926
927/*
928 * Read /etc/default/login.
929 * We pick up the PATH (or SUPATH for root) and UMASK.
930 */
931static void
932read_etc_default_login(char ***env, u_int *envsize, uid_t uid)
933{
934	char **tmpenv = NULL, *var;
935	u_int i, tmpenvsize = 0;
936	u_long mask;
937
938	/*
939	 * We don't want to copy the whole file to the child's environment,
940	 * so we use a temporary environment and copy the variables we're
941	 * interested in.
942	 */
943	read_environment_file(&tmpenv, &tmpenvsize, "/etc/default/login");
944
945	if (tmpenv == NULL)
946		return;
947
948	if (uid == 0)
949		var = child_get_env(tmpenv, "SUPATH");
950	else
951		var = child_get_env(tmpenv, "PATH");
952	if (var != NULL)
953		child_set_env(env, envsize, "PATH", var);
954
955	if ((var = child_get_env(tmpenv, "UMASK")) != NULL)
956		if (sscanf(var, "%5lo", &mask) == 1)
957			umask((mode_t)mask);
958
959	for (i = 0; tmpenv[i] != NULL; i++)
960		xfree(tmpenv[i]);
961	xfree(tmpenv);
962}
963#endif /* HAVE_ETC_DEFAULT_LOGIN */
964
965void copy_environment(char **source, char ***env, u_int *envsize)
966{
967	char *var_name, *var_val;
968	int i;
969
970	if (source == NULL)
971		return;
972
973	for(i = 0; source[i] != NULL; i++) {
974		var_name = xstrdup(source[i]);
975		if ((var_val = strstr(var_name, "=")) == NULL) {
976			xfree(var_name);
977			continue;
978		}
979		*var_val++ = '\0';
980
981		debug3("Copy environment: %s=%s", var_name, var_val);
982		child_set_env(env, envsize, var_name, var_val);
983
984		xfree(var_name);
985	}
986}
987
988static char **
989do_setup_env(Session *s, const char *shell)
990{
991	char buf[256];
992	u_int i, envsize;
993	char **env, *laddr, *path = NULL;
994#ifdef HAVE_LOGIN_CAP
995	extern char **environ;
996	char **senv, **var;
997#endif
998	struct passwd *pw = s->pw;
999
1000	/* Initialize the environment. */
1001	envsize = 100;
1002	env = xmalloc(envsize * sizeof(char *));
1003	env[0] = NULL;
1004
1005#ifdef HAVE_CYGWIN
1006	/*
1007	 * The Windows environment contains some setting which are
1008	 * important for a running system. They must not be dropped.
1009	 */
1010	copy_environment(environ, &env, &envsize);
1011#endif
1012
1013	if (getenv("TZ"))
1014		child_set_env(&env, &envsize, "TZ", getenv("TZ"));
1015
1016#ifdef GSSAPI
1017	/* Allow any GSSAPI methods that we've used to alter
1018	 * the childs environment as they see fit
1019	 */
1020	ssh_gssapi_do_child(&env, &envsize);
1021#endif
1022
1023	if (!options.use_login) {
1024		/* Set basic environment. */
1025		child_set_env(&env, &envsize, "USER", pw->pw_name);
1026		child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
1027#ifdef _AIX
1028		child_set_env(&env, &envsize, "LOGIN", pw->pw_name);
1029#endif
1030		child_set_env(&env, &envsize, "HOME", pw->pw_dir);
1031		snprintf(buf, sizeof buf, "%.200s/%.50s",
1032			 _PATH_MAILDIR, pw->pw_name);
1033		child_set_env(&env, &envsize, "MAIL", buf);
1034#ifdef HAVE_LOGIN_CAP
1035		child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
1036		child_set_env(&env, &envsize, "TERM", "su");
1037		senv = environ;
1038		environ = xmalloc(sizeof(char *));
1039		*environ = NULL;
1040		(void) setusercontext(lc, pw, pw->pw_uid,
1041		    LOGIN_SETENV|LOGIN_SETPATH);
1042		copy_environment(environ, &env, &envsize);
1043		for (var = environ; *var != NULL; ++var)
1044			xfree(*var);
1045		xfree(environ);
1046		environ = senv;
1047#else /* HAVE_LOGIN_CAP */
1048# ifndef HAVE_CYGWIN
1049		/*
1050		 * There's no standard path on Windows. The path contains
1051		 * important components pointing to the system directories,
1052		 * needed for loading shared libraries. So the path better
1053		 * remains intact here.
1054		 */
1055#  ifdef HAVE_ETC_DEFAULT_LOGIN
1056		read_etc_default_login(&env, &envsize, pw->pw_uid);
1057		path = child_get_env(env, "PATH");
1058#  endif /* HAVE_ETC_DEFAULT_LOGIN */
1059		if (path == NULL || *path == '\0') {
1060			child_set_env(&env, &envsize, "PATH",
1061			    s->pw->pw_uid == 0 ?
1062				SUPERUSER_PATH : _PATH_STDPATH);
1063		}
1064# endif /* HAVE_CYGWIN */
1065#endif /* HAVE_LOGIN_CAP */
1066
1067		/* Normal systems set SHELL by default. */
1068		child_set_env(&env, &envsize, "SHELL", shell);
1069	}
1070
1071	/* Set custom environment options from RSA authentication. */
1072	if (!options.use_login) {
1073		while (custom_environment) {
1074			struct envstring *ce = custom_environment;
1075			char *str = ce->s;
1076
1077			for (i = 0; str[i] != '=' && str[i]; i++)
1078				;
1079			if (str[i] == '=') {
1080				str[i] = 0;
1081				child_set_env(&env, &envsize, str, str + i + 1);
1082			}
1083			custom_environment = ce->next;
1084			xfree(ce->s);
1085			xfree(ce);
1086		}
1087	}
1088
1089	/* SSH_CLIENT deprecated */
1090	snprintf(buf, sizeof buf, "%.50s %d %d",
1091	    get_remote_ipaddr(), get_remote_port(), get_local_port());
1092	child_set_env(&env, &envsize, "SSH_CLIENT", buf);
1093
1094	laddr = get_local_ipaddr(packet_get_connection_in());
1095	snprintf(buf, sizeof buf, "%.50s %d %.50s %d",
1096	    get_remote_ipaddr(), get_remote_port(), laddr, get_local_port());
1097	xfree(laddr);
1098	child_set_env(&env, &envsize, "SSH_CONNECTION", buf);
1099
1100	if (s->ttyfd != -1)
1101		child_set_env(&env, &envsize, "SSH_TTY", s->tty);
1102	if (s->term)
1103		child_set_env(&env, &envsize, "TERM", s->term);
1104	if (s->display)
1105		child_set_env(&env, &envsize, "DISPLAY", s->display);
1106	if (original_command)
1107		child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
1108		    original_command);
1109
1110#ifdef _UNICOS
1111	if (cray_tmpdir[0] != '\0')
1112		child_set_env(&env, &envsize, "TMPDIR", cray_tmpdir);
1113#endif /* _UNICOS */
1114
1115#ifdef _AIX
1116	{
1117		char *cp;
1118
1119		if ((cp = getenv("AUTHSTATE")) != NULL)
1120			child_set_env(&env, &envsize, "AUTHSTATE", cp);
1121		if ((cp = getenv("KRB5CCNAME")) != NULL)
1122			child_set_env(&env, &envsize, "KRB5CCNAME", cp);
1123		read_environment_file(&env, &envsize, "/etc/environment");
1124	}
1125#endif
1126#ifdef KRB5
1127	if (s->authctxt->krb5_ccname)
1128		child_set_env(&env, &envsize, "KRB5CCNAME",
1129		    s->authctxt->krb5_ccname);
1130#endif
1131#ifdef USE_PAM
1132	/*
1133	 * Pull in any environment variables that may have
1134	 * been set by PAM.
1135	 */
1136	if (options.use_pam) {
1137		char **p;
1138
1139		p = fetch_pam_child_environment();
1140		copy_environment(p, &env, &envsize);
1141		free_pam_environment(p);
1142
1143		p = fetch_pam_environment();
1144		copy_environment(p, &env, &envsize);
1145		free_pam_environment(p);
1146	}
1147#endif /* USE_PAM */
1148
1149	if (auth_sock_name != NULL)
1150		child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
1151		    auth_sock_name);
1152
1153	/* read $HOME/.ssh/environment. */
1154	if (options.permit_user_env && !options.use_login) {
1155		snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
1156		    strcmp(pw->pw_dir, "/") ? pw->pw_dir : "");
1157		read_environment_file(&env, &envsize, buf);
1158	}
1159	if (debug_flag) {
1160		/* dump the environment */
1161		fprintf(stderr, "Environment:\n");
1162		for (i = 0; env[i]; i++)
1163			fprintf(stderr, "  %.200s\n", env[i]);
1164	}
1165	return env;
1166}
1167
1168/*
1169 * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found
1170 * first in this order).
1171 */
1172static void
1173do_rc_files(Session *s, const char *shell)
1174{
1175	FILE *f = NULL;
1176	char cmd[1024];
1177	int do_xauth;
1178	struct stat st;
1179
1180	do_xauth =
1181	    s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
1182
1183	/* ignore _PATH_SSH_USER_RC for subsystems */
1184	if (!s->is_subsystem && (stat(_PATH_SSH_USER_RC, &st) >= 0)) {
1185		snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
1186		    shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
1187		if (debug_flag)
1188			fprintf(stderr, "Running %s\n", cmd);
1189		f = popen(cmd, "w");
1190		if (f) {
1191			if (do_xauth)
1192				fprintf(f, "%s %s\n", s->auth_proto,
1193				    s->auth_data);
1194			pclose(f);
1195		} else
1196			fprintf(stderr, "Could not run %s\n",
1197			    _PATH_SSH_USER_RC);
1198	} else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
1199		if (debug_flag)
1200			fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
1201			    _PATH_SSH_SYSTEM_RC);
1202		f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
1203		if (f) {
1204			if (do_xauth)
1205				fprintf(f, "%s %s\n", s->auth_proto,
1206				    s->auth_data);
1207			pclose(f);
1208		} else
1209			fprintf(stderr, "Could not run %s\n",
1210			    _PATH_SSH_SYSTEM_RC);
1211	} else if (do_xauth && options.xauth_location != NULL) {
1212		/* Add authority data to .Xauthority if appropriate. */
1213		if (debug_flag) {
1214			fprintf(stderr,
1215			    "Running %.500s remove %.100s\n",
1216			    options.xauth_location, s->auth_display);
1217			fprintf(stderr,
1218			    "%.500s add %.100s %.100s %.100s\n",
1219			    options.xauth_location, s->auth_display,
1220			    s->auth_proto, s->auth_data);
1221		}
1222		snprintf(cmd, sizeof cmd, "%s -q -",
1223		    options.xauth_location);
1224		f = popen(cmd, "w");
1225		if (f) {
1226			fprintf(f, "remove %s\n",
1227			    s->auth_display);
1228			fprintf(f, "add %s %s %s\n",
1229			    s->auth_display, s->auth_proto,
1230			    s->auth_data);
1231			pclose(f);
1232		} else {
1233			fprintf(stderr, "Could not run %s\n",
1234			    cmd);
1235		}
1236	}
1237}
1238
1239static void
1240do_nologin(struct passwd *pw)
1241{
1242	FILE *f = NULL;
1243	char buf[1024];
1244
1245#ifdef HAVE_LOGIN_CAP
1246	if (!login_getcapbool(lc, "ignorenologin", 0) && pw->pw_uid)
1247		f = fopen(login_getcapstr(lc, "nologin", _PATH_NOLOGIN,
1248		    _PATH_NOLOGIN), "r");
1249#else
1250	if (pw->pw_uid)
1251		f = fopen(_PATH_NOLOGIN, "r");
1252#endif
1253	if (f) {
1254		/* /etc/nologin exists.  Print its contents and exit. */
1255		logit("User %.100s not allowed because %s exists",
1256		    pw->pw_name, _PATH_NOLOGIN);
1257		while (fgets(buf, sizeof(buf), f))
1258			fputs(buf, stderr);
1259		fclose(f);
1260		fflush(NULL);
1261		exit(254);
1262	}
1263}
1264
1265/* Set login name, uid, gid, and groups. */
1266void
1267do_setusercontext(struct passwd *pw)
1268{
1269#ifndef HAVE_CYGWIN
1270	if (getuid() == 0 || geteuid() == 0)
1271#endif /* HAVE_CYGWIN */
1272	{
1273
1274#ifdef HAVE_SETPCRED
1275		if (setpcred(pw->pw_name, (char **)NULL) == -1)
1276			fatal("Failed to set process credentials");
1277#endif /* HAVE_SETPCRED */
1278#ifdef HAVE_LOGIN_CAP
1279# ifdef __bsdi__
1280		setpgid(0, 0);
1281# endif
1282# ifdef USE_PAM
1283		if (options.use_pam) {
1284			do_pam_session();
1285			do_pam_setcred(0);
1286		}
1287# endif /* USE_PAM */
1288		if (setusercontext(lc, pw, pw->pw_uid,
1289		    (LOGIN_SETALL & ~(LOGIN_SETENV|LOGIN_SETPATH))) < 0) {
1290			perror("unable to set user context");
1291			exit(1);
1292		}
1293#else
1294# if defined(HAVE_GETLUID) && defined(HAVE_SETLUID)
1295		/* Sets login uid for accounting */
1296		if (getluid() == -1 && setluid(pw->pw_uid) == -1)
1297			error("setluid: %s", strerror(errno));
1298# endif /* defined(HAVE_GETLUID) && defined(HAVE_SETLUID) */
1299
1300		if (setlogin(pw->pw_name) < 0)
1301			error("setlogin failed: %s", strerror(errno));
1302		if (setgid(pw->pw_gid) < 0) {
1303			perror("setgid");
1304			exit(1);
1305		}
1306		/* Initialize the group list. */
1307		if (initgroups(pw->pw_name, pw->pw_gid) < 0) {
1308			perror("initgroups");
1309			exit(1);
1310		}
1311		endgrent();
1312# ifdef USE_PAM
1313		/*
1314		 * PAM credentials may take the form of supplementary groups.
1315		 * These will have been wiped by the above initgroups() call.
1316		 * Reestablish them here.
1317		 */
1318		if (options.use_pam) {
1319			do_pam_session();
1320			do_pam_setcred(0);
1321		}
1322# endif /* USE_PAM */
1323# if defined(WITH_IRIX_PROJECT) || defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY)
1324		irix_setusercontext(pw);
1325#  endif /* defined(WITH_IRIX_PROJECT) || defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY) */
1326# ifdef _AIX
1327		aix_usrinfo(pw);
1328# endif /* _AIX */
1329		/* Permanently switch to the desired uid. */
1330		permanently_set_uid(pw);
1331#endif
1332	}
1333
1334#ifdef HAVE_CYGWIN
1335	if (is_winnt)
1336#endif
1337	if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
1338		fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
1339}
1340
1341static void
1342do_pwchange(Session *s)
1343{
1344	fprintf(stderr, "WARNING: Your password has expired.\n");
1345	if (s->ttyfd != -1) {
1346	    	fprintf(stderr,
1347		    "You must change your password now and login again!\n");
1348		execl(_PATH_PASSWD_PROG, "passwd", (char *)NULL);
1349		perror("passwd");
1350	} else {
1351		fprintf(stderr,
1352		    "Password change required but no TTY available.\n");
1353	}
1354	exit(1);
1355}
1356
1357static void
1358launch_login(struct passwd *pw, const char *hostname)
1359{
1360	/* Launch login(1). */
1361
1362	execl(LOGIN_PROGRAM, "login", "-h", hostname,
1363#ifdef xxxLOGIN_NEEDS_TERM
1364		    (s->term ? s->term : "unknown"),
1365#endif /* LOGIN_NEEDS_TERM */
1366#ifdef LOGIN_NO_ENDOPT
1367	    "-p", "-f", pw->pw_name, (char *)NULL);
1368#else
1369	    "-p", "-f", "--", pw->pw_name, (char *)NULL);
1370#endif
1371
1372	/* Login couldn't be executed, die. */
1373
1374	perror("login");
1375	exit(1);
1376}
1377
1378static void
1379child_close_fds(void)
1380{
1381	int i;
1382
1383	if (packet_get_connection_in() == packet_get_connection_out())
1384		close(packet_get_connection_in());
1385	else {
1386		close(packet_get_connection_in());
1387		close(packet_get_connection_out());
1388	}
1389	/*
1390	 * Close all descriptors related to channels.  They will still remain
1391	 * open in the parent.
1392	 */
1393	/* XXX better use close-on-exec? -markus */
1394	channel_close_all();
1395
1396	/*
1397	 * Close any extra file descriptors.  Note that there may still be
1398	 * descriptors left by system functions.  They will be closed later.
1399	 */
1400	endpwent();
1401
1402	/*
1403	 * Close any extra open file descriptors so that we don\'t have them
1404	 * hanging around in clients.  Note that we want to do this after
1405	 * initgroups, because at least on Solaris 2.3 it leaves file
1406	 * descriptors open.
1407	 */
1408	for (i = 3; i < 64; i++)
1409		close(i);
1410}
1411
1412/*
1413 * Performs common processing for the child, such as setting up the
1414 * environment, closing extra file descriptors, setting the user and group
1415 * ids, and executing the command or shell.
1416 */
1417void
1418do_child(Session *s, const char *command)
1419{
1420	extern char **environ;
1421	char **env;
1422	char *argv[10];
1423	const char *shell, *shell0, *hostname = NULL;
1424	struct passwd *pw = s->pw;
1425#ifdef HAVE_LOGIN_CAP
1426	int lc_requirehome;
1427#endif
1428
1429	/* remove hostkey from the child's memory */
1430	destroy_sensitive_data();
1431
1432	/* Force a password change */
1433	if (s->authctxt->force_pwchange) {
1434		do_setusercontext(pw);
1435		child_close_fds();
1436		do_pwchange(s);
1437		exit(1);
1438	}
1439
1440	/* login(1) is only called if we execute the login shell */
1441	if (options.use_login && command != NULL)
1442		options.use_login = 0;
1443
1444#ifdef _UNICOS
1445	cray_setup(pw->pw_uid, pw->pw_name, command);
1446#endif /* _UNICOS */
1447
1448	/*
1449	 * Login(1) does this as well, and it needs uid 0 for the "-h"
1450	 * switch, so we let login(1) to this for us.
1451	 */
1452	if (!options.use_login) {
1453#ifdef HAVE_OSF_SIA
1454		session_setup_sia(pw, s->ttyfd == -1 ? NULL : s->tty);
1455		if (!check_quietlogin(s, command))
1456			do_motd();
1457#else /* HAVE_OSF_SIA */
1458		do_nologin(pw);
1459		do_setusercontext(pw);
1460#endif /* HAVE_OSF_SIA */
1461	}
1462
1463	/*
1464	 * Get the shell from the password data.  An empty shell field is
1465	 * legal, and means /bin/sh.
1466	 */
1467	shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1468
1469	/*
1470	 * Make sure $SHELL points to the shell from the password file,
1471	 * even if shell is overridden from login.conf
1472	 */
1473	env = do_setup_env(s, shell);
1474
1475#ifdef HAVE_LOGIN_CAP
1476	shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
1477#endif
1478
1479	/* we have to stash the hostname before we close our socket. */
1480	if (options.use_login)
1481		hostname = get_remote_name_or_ip(utmp_len,
1482		    options.use_dns);
1483	/*
1484	 * Close the connection descriptors; note that this is the child, and
1485	 * the server will still have the socket open, and it is important
1486	 * that we do not shutdown it.  Note that the descriptors cannot be
1487	 * closed before building the environment, as we call
1488	 * get_remote_ipaddr there.
1489	 */
1490	child_close_fds();
1491
1492	/*
1493	 * Must take new environment into use so that .ssh/rc,
1494	 * /etc/ssh/sshrc and xauth are run in the proper environment.
1495	 */
1496	environ = env;
1497
1498#ifdef HAVE_LOGIN_CAP
1499	lc_requirehome = login_getcapbool(lc, "requirehome", 0);
1500	login_close(lc);
1501#endif
1502#if defined(KRB5) && defined(USE_AFS)
1503	/*
1504	 * At this point, we check to see if AFS is active and if we have
1505	 * a valid Kerberos 5 TGT. If so, it seems like a good idea to see
1506	 * if we can (and need to) extend the ticket into an AFS token. If
1507	 * we don't do this, we run into potential problems if the user's
1508	 * home directory is in AFS and it's not world-readable.
1509	 */
1510
1511	if (options.kerberos_get_afs_token && k_hasafs() &&
1512	     (s->authctxt->krb5_ctx != NULL)) {
1513		char cell[64];
1514
1515		debug("Getting AFS token");
1516
1517		k_setpag();
1518
1519		if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
1520			krb5_afslog(s->authctxt->krb5_ctx,
1521			    s->authctxt->krb5_fwd_ccache, cell, NULL);
1522
1523		krb5_afslog_home(s->authctxt->krb5_ctx,
1524		    s->authctxt->krb5_fwd_ccache, NULL, NULL, pw->pw_dir);
1525	}
1526#endif
1527
1528	/* Change current directory to the user\'s home directory. */
1529	if (chdir(pw->pw_dir) < 0) {
1530		fprintf(stderr, "Could not chdir to home directory %s: %s\n",
1531		    pw->pw_dir, strerror(errno));
1532#ifdef HAVE_LOGIN_CAP
1533		if (lc_requirehome)
1534			exit(1);
1535#endif
1536	}
1537
1538	if (!options.use_login)
1539		do_rc_files(s, shell);
1540
1541	/* restore SIGPIPE for child */
1542	signal(SIGPIPE,  SIG_DFL);
1543
1544	if (options.use_login) {
1545		launch_login(pw, hostname);
1546		/* NEVERREACHED */
1547	}
1548
1549	/* Get the last component of the shell name. */
1550	if ((shell0 = strrchr(shell, '/')) != NULL)
1551		shell0++;
1552	else
1553		shell0 = shell;
1554
1555	/*
1556	 * If we have no command, execute the shell.  In this case, the shell
1557	 * name to be passed in argv[0] is preceded by '-' to indicate that
1558	 * this is a login shell.
1559	 */
1560	if (!command) {
1561		char argv0[256];
1562
1563		/* Start the shell.  Set initial character to '-'. */
1564		argv0[0] = '-';
1565
1566		if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1)
1567		    >= sizeof(argv0) - 1) {
1568			errno = EINVAL;
1569			perror(shell);
1570			exit(1);
1571		}
1572
1573		/* Execute the shell. */
1574		argv[0] = argv0;
1575		argv[1] = NULL;
1576		execve(shell, argv, env);
1577
1578		/* Executing the shell failed. */
1579		perror(shell);
1580		exit(1);
1581	}
1582	/*
1583	 * Execute the command using the user's shell.  This uses the -c
1584	 * option to execute the command.
1585	 */
1586	argv[0] = (char *) shell0;
1587	argv[1] = "-c";
1588	argv[2] = (char *) command;
1589	argv[3] = NULL;
1590	execve(shell, argv, env);
1591	perror(shell);
1592	exit(1);
1593}
1594
1595Session *
1596session_new(void)
1597{
1598	int i;
1599	static int did_init = 0;
1600	if (!did_init) {
1601		debug("session_new: init");
1602		for (i = 0; i < MAX_SESSIONS; i++) {
1603			sessions[i].used = 0;
1604		}
1605		did_init = 1;
1606	}
1607	for (i = 0; i < MAX_SESSIONS; i++) {
1608		Session *s = &sessions[i];
1609		if (! s->used) {
1610			memset(s, 0, sizeof(*s));
1611			s->chanid = -1;
1612			s->ptyfd = -1;
1613			s->ttyfd = -1;
1614			s->used = 1;
1615			s->self = i;
1616			debug("session_new: session %d", i);
1617			return s;
1618		}
1619	}
1620	return NULL;
1621}
1622
1623static void
1624session_dump(void)
1625{
1626	int i;
1627	for (i = 0; i < MAX_SESSIONS; i++) {
1628		Session *s = &sessions[i];
1629		debug("dump: used %d session %d %p channel %d pid %ld",
1630		    s->used,
1631		    s->self,
1632		    s,
1633		    s->chanid,
1634		    (long)s->pid);
1635	}
1636}
1637
1638int
1639session_open(Authctxt *authctxt, int chanid)
1640{
1641	Session *s = session_new();
1642	debug("session_open: channel %d", chanid);
1643	if (s == NULL) {
1644		error("no more sessions");
1645		return 0;
1646	}
1647	s->authctxt = authctxt;
1648	s->pw = authctxt->pw;
1649	if (s->pw == NULL || !authctxt->valid)
1650		fatal("no user for session %d", s->self);
1651	debug("session_open: session %d: link with channel %d", s->self, chanid);
1652	s->chanid = chanid;
1653	return 1;
1654}
1655
1656Session *
1657session_by_tty(char *tty)
1658{
1659	int i;
1660	for (i = 0; i < MAX_SESSIONS; i++) {
1661		Session *s = &sessions[i];
1662		if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) {
1663			debug("session_by_tty: session %d tty %s", i, tty);
1664			return s;
1665		}
1666	}
1667	debug("session_by_tty: unknown tty %.100s", tty);
1668	session_dump();
1669	return NULL;
1670}
1671
1672static Session *
1673session_by_channel(int id)
1674{
1675	int i;
1676	for (i = 0; i < MAX_SESSIONS; i++) {
1677		Session *s = &sessions[i];
1678		if (s->used && s->chanid == id) {
1679			debug("session_by_channel: session %d channel %d", i, id);
1680			return s;
1681		}
1682	}
1683	debug("session_by_channel: unknown channel %d", id);
1684	session_dump();
1685	return NULL;
1686}
1687
1688static Session *
1689session_by_pid(pid_t pid)
1690{
1691	int i;
1692	debug("session_by_pid: pid %ld", (long)pid);
1693	for (i = 0; i < MAX_SESSIONS; i++) {
1694		Session *s = &sessions[i];
1695		if (s->used && s->pid == pid)
1696			return s;
1697	}
1698	error("session_by_pid: unknown pid %ld", (long)pid);
1699	session_dump();
1700	return NULL;
1701}
1702
1703static int
1704session_window_change_req(Session *s)
1705{
1706	s->col = packet_get_int();
1707	s->row = packet_get_int();
1708	s->xpixel = packet_get_int();
1709	s->ypixel = packet_get_int();
1710	packet_check_eom();
1711	pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1712	return 1;
1713}
1714
1715static int
1716session_pty_req(Session *s)
1717{
1718	u_int len;
1719	int n_bytes;
1720
1721	if (no_pty_flag) {
1722		debug("Allocating a pty not permitted for this authentication.");
1723		return 0;
1724	}
1725	if (s->ttyfd != -1) {
1726		packet_disconnect("Protocol error: you already have a pty.");
1727		return 0;
1728	}
1729	/* Get the time and hostname when the user last logged in. */
1730	if (options.print_lastlog) {
1731		s->hostname[0] = '\0';
1732		s->last_login_time = get_last_login_time(s->pw->pw_uid,
1733		    s->pw->pw_name, s->hostname, sizeof(s->hostname));
1734	}
1735
1736	s->term = packet_get_string(&len);
1737
1738	if (compat20) {
1739		s->col = packet_get_int();
1740		s->row = packet_get_int();
1741	} else {
1742		s->row = packet_get_int();
1743		s->col = packet_get_int();
1744	}
1745	s->xpixel = packet_get_int();
1746	s->ypixel = packet_get_int();
1747
1748	if (strcmp(s->term, "") == 0) {
1749		xfree(s->term);
1750		s->term = NULL;
1751	}
1752
1753	/* Allocate a pty and open it. */
1754	debug("Allocating pty.");
1755	if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty)))) {
1756		if (s->term)
1757			xfree(s->term);
1758		s->term = NULL;
1759		s->ptyfd = -1;
1760		s->ttyfd = -1;
1761		error("session_pty_req: session %d alloc failed", s->self);
1762		return 0;
1763	}
1764	debug("session_pty_req: session %d alloc %s", s->self, s->tty);
1765
1766	/* for SSH1 the tty modes length is not given */
1767	if (!compat20)
1768		n_bytes = packet_remaining();
1769	tty_parse_modes(s->ttyfd, &n_bytes);
1770
1771	if (!use_privsep)
1772		pty_setowner(s->pw, s->tty);
1773
1774	/* Set window size from the packet. */
1775	pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1776
1777	packet_check_eom();
1778	session_proctitle(s);
1779	return 1;
1780}
1781
1782static int
1783session_subsystem_req(Session *s)
1784{
1785	struct stat st;
1786	u_int len;
1787	int success = 0;
1788	char *cmd, *subsys = packet_get_string(&len);
1789	int i;
1790
1791	packet_check_eom();
1792	logit("subsystem request for %.100s", subsys);
1793
1794	for (i = 0; i < options.num_subsystems; i++) {
1795		if (strcmp(subsys, options.subsystem_name[i]) == 0) {
1796			cmd = options.subsystem_command[i];
1797			if (stat(cmd, &st) < 0) {
1798				error("subsystem: cannot stat %s: %s", cmd,
1799				    strerror(errno));
1800				break;
1801			}
1802			debug("subsystem: exec() %s", cmd);
1803			s->is_subsystem = 1;
1804			do_exec(s, cmd);
1805			success = 1;
1806			break;
1807		}
1808	}
1809
1810	if (!success)
1811		logit("subsystem request for %.100s failed, subsystem not found",
1812		    subsys);
1813
1814	xfree(subsys);
1815	return success;
1816}
1817
1818static int
1819session_x11_req(Session *s)
1820{
1821	int success;
1822
1823	s->single_connection = packet_get_char();
1824	s->auth_proto = packet_get_string(NULL);
1825	s->auth_data = packet_get_string(NULL);
1826	s->screen = packet_get_int();
1827	packet_check_eom();
1828
1829	success = session_setup_x11fwd(s);
1830	if (!success) {
1831		xfree(s->auth_proto);
1832		xfree(s->auth_data);
1833		s->auth_proto = NULL;
1834		s->auth_data = NULL;
1835	}
1836	return success;
1837}
1838
1839static int
1840session_shell_req(Session *s)
1841{
1842	packet_check_eom();
1843	do_exec(s, NULL);
1844	return 1;
1845}
1846
1847static int
1848session_exec_req(Session *s)
1849{
1850	u_int len;
1851	char *command = packet_get_string(&len);
1852	packet_check_eom();
1853	do_exec(s, command);
1854	xfree(command);
1855	return 1;
1856}
1857
1858static int
1859session_break_req(Session *s)
1860{
1861	u_int break_length;
1862
1863	break_length = packet_get_int();	/* ignored */
1864	packet_check_eom();
1865
1866	if (s->ttyfd == -1 ||
1867	    tcsendbreak(s->ttyfd, 0) < 0)
1868		return 0;
1869	return 1;
1870}
1871
1872static int
1873session_auth_agent_req(Session *s)
1874{
1875	static int called = 0;
1876	packet_check_eom();
1877	if (no_agent_forwarding_flag) {
1878		debug("session_auth_agent_req: no_agent_forwarding_flag");
1879		return 0;
1880	}
1881	if (called) {
1882		return 0;
1883	} else {
1884		called = 1;
1885		return auth_input_request_forwarding(s->pw);
1886	}
1887}
1888
1889int
1890session_input_channel_req(Channel *c, const char *rtype)
1891{
1892	int success = 0;
1893	Session *s;
1894
1895	if ((s = session_by_channel(c->self)) == NULL) {
1896		logit("session_input_channel_req: no session %d req %.100s",
1897		    c->self, rtype);
1898		return 0;
1899	}
1900	debug("session_input_channel_req: session %d req %s", s->self, rtype);
1901
1902	/*
1903	 * a session is in LARVAL state until a shell, a command
1904	 * or a subsystem is executed
1905	 */
1906	if (c->type == SSH_CHANNEL_LARVAL) {
1907		if (strcmp(rtype, "shell") == 0) {
1908			success = session_shell_req(s);
1909		} else if (strcmp(rtype, "exec") == 0) {
1910			success = session_exec_req(s);
1911		} else if (strcmp(rtype, "pty-req") == 0) {
1912			success =  session_pty_req(s);
1913		} else if (strcmp(rtype, "x11-req") == 0) {
1914			success = session_x11_req(s);
1915		} else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
1916			success = session_auth_agent_req(s);
1917		} else if (strcmp(rtype, "subsystem") == 0) {
1918			success = session_subsystem_req(s);
1919		} else if (strcmp(rtype, "break") == 0) {
1920			success = session_break_req(s);
1921		}
1922	}
1923	if (strcmp(rtype, "window-change") == 0) {
1924		success = session_window_change_req(s);
1925	}
1926	return success;
1927}
1928
1929void
1930session_set_fds(Session *s, int fdin, int fdout, int fderr)
1931{
1932	if (!compat20)
1933		fatal("session_set_fds: called for proto != 2.0");
1934	/*
1935	 * now that have a child and a pipe to the child,
1936	 * we can activate our channel and register the fd's
1937	 */
1938	if (s->chanid == -1)
1939		fatal("no channel for session %d", s->self);
1940	channel_set_fds(s->chanid,
1941	    fdout, fdin, fderr,
1942	    fderr == -1 ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
1943	    1,
1944	    CHAN_SES_WINDOW_DEFAULT);
1945}
1946
1947/*
1948 * Function to perform pty cleanup. Also called if we get aborted abnormally
1949 * (e.g., due to a dropped connection).
1950 */
1951void
1952session_pty_cleanup2(Session *s)
1953{
1954	if (s == NULL) {
1955		error("session_pty_cleanup: no session");
1956		return;
1957	}
1958	if (s->ttyfd == -1)
1959		return;
1960
1961	debug("session_pty_cleanup: session %d release %s", s->self, s->tty);
1962
1963	/* Record that the user has logged out. */
1964	if (s->pid != 0)
1965		record_logout(s->pid, s->tty, s->pw->pw_name);
1966
1967	/* Release the pseudo-tty. */
1968	if (getuid() == 0)
1969		pty_release(s->tty);
1970
1971	/*
1972	 * Close the server side of the socket pairs.  We must do this after
1973	 * the pty cleanup, so that another process doesn't get this pty
1974	 * while we're still cleaning up.
1975	 */
1976	if (close(s->ptymaster) < 0)
1977		error("close(s->ptymaster/%d): %s", s->ptymaster, strerror(errno));
1978
1979	/* unlink pty from session */
1980	s->ttyfd = -1;
1981}
1982
1983void
1984session_pty_cleanup(Session *s)
1985{
1986	PRIVSEP(session_pty_cleanup2(s));
1987}
1988
1989static char *
1990sig2name(int sig)
1991{
1992#define SSH_SIG(x) if (sig == SIG ## x) return #x
1993	SSH_SIG(ABRT);
1994	SSH_SIG(ALRM);
1995	SSH_SIG(FPE);
1996	SSH_SIG(HUP);
1997	SSH_SIG(ILL);
1998	SSH_SIG(INT);
1999	SSH_SIG(KILL);
2000	SSH_SIG(PIPE);
2001	SSH_SIG(QUIT);
2002	SSH_SIG(SEGV);
2003	SSH_SIG(TERM);
2004	SSH_SIG(USR1);
2005	SSH_SIG(USR2);
2006#undef	SSH_SIG
2007	return "SIG@openssh.com";
2008}
2009
2010static void
2011session_exit_message(Session *s, int status)
2012{
2013	Channel *c;
2014
2015	if ((c = channel_lookup(s->chanid)) == NULL)
2016		fatal("session_exit_message: session %d: no channel %d",
2017		    s->self, s->chanid);
2018	debug("session_exit_message: session %d channel %d pid %ld",
2019	    s->self, s->chanid, (long)s->pid);
2020
2021	if (WIFEXITED(status)) {
2022		channel_request_start(s->chanid, "exit-status", 0);
2023		packet_put_int(WEXITSTATUS(status));
2024		packet_send();
2025	} else if (WIFSIGNALED(status)) {
2026		channel_request_start(s->chanid, "exit-signal", 0);
2027		packet_put_cstring(sig2name(WTERMSIG(status)));
2028#ifdef WCOREDUMP
2029		packet_put_char(WCOREDUMP(status));
2030#else /* WCOREDUMP */
2031		packet_put_char(0);
2032#endif /* WCOREDUMP */
2033		packet_put_cstring("");
2034		packet_put_cstring("");
2035		packet_send();
2036	} else {
2037		/* Some weird exit cause.  Just exit. */
2038		packet_disconnect("wait returned status %04x.", status);
2039	}
2040
2041	/* disconnect channel */
2042	debug("session_exit_message: release channel %d", s->chanid);
2043	channel_cancel_cleanup(s->chanid);
2044	/*
2045	 * emulate a write failure with 'chan_write_failed', nobody will be
2046	 * interested in data we write.
2047	 * Note that we must not call 'chan_read_failed', since there could
2048	 * be some more data waiting in the pipe.
2049	 */
2050	if (c->ostate != CHAN_OUTPUT_CLOSED)
2051		chan_write_failed(c);
2052	s->chanid = -1;
2053}
2054
2055void
2056session_close(Session *s)
2057{
2058	debug("session_close: session %d pid %ld", s->self, (long)s->pid);
2059	if (s->ttyfd != -1)
2060		session_pty_cleanup(s);
2061	if (s->term)
2062		xfree(s->term);
2063	if (s->display)
2064		xfree(s->display);
2065	if (s->auth_display)
2066		xfree(s->auth_display);
2067	if (s->auth_data)
2068		xfree(s->auth_data);
2069	if (s->auth_proto)
2070		xfree(s->auth_proto);
2071	s->used = 0;
2072	session_proctitle(s);
2073}
2074
2075void
2076session_close_by_pid(pid_t pid, int status)
2077{
2078	Session *s = session_by_pid(pid);
2079	if (s == NULL) {
2080		debug("session_close_by_pid: no session for pid %ld",
2081		    (long)pid);
2082		return;
2083	}
2084	if (s->chanid != -1)
2085		session_exit_message(s, status);
2086	session_close(s);
2087}
2088
2089/*
2090 * this is called when a channel dies before
2091 * the session 'child' itself dies
2092 */
2093void
2094session_close_by_channel(int id, void *arg)
2095{
2096	Session *s = session_by_channel(id);
2097	if (s == NULL) {
2098		debug("session_close_by_channel: no session for id %d", id);
2099		return;
2100	}
2101	debug("session_close_by_channel: channel %d child %ld",
2102	    id, (long)s->pid);
2103	if (s->pid != 0) {
2104		debug("session_close_by_channel: channel %d: has child", id);
2105		/*
2106		 * delay detach of session, but release pty, since
2107		 * the fd's to the child are already closed
2108		 */
2109		if (s->ttyfd != -1)
2110			session_pty_cleanup(s);
2111		return;
2112	}
2113	/* detach by removing callback */
2114	channel_cancel_cleanup(s->chanid);
2115	s->chanid = -1;
2116	session_close(s);
2117}
2118
2119void
2120session_destroy_all(void (*closefunc)(Session *))
2121{
2122	int i;
2123	for (i = 0; i < MAX_SESSIONS; i++) {
2124		Session *s = &sessions[i];
2125		if (s->used) {
2126			if (closefunc != NULL)
2127				closefunc(s);
2128			else
2129				session_close(s);
2130		}
2131	}
2132}
2133
2134static char *
2135session_tty_list(void)
2136{
2137	static char buf[1024];
2138	int i;
2139	char *cp;
2140
2141	buf[0] = '\0';
2142	for (i = 0; i < MAX_SESSIONS; i++) {
2143		Session *s = &sessions[i];
2144		if (s->used && s->ttyfd != -1) {
2145
2146			if (strncmp(s->tty, "/dev/", 5) != 0) {
2147				cp = strrchr(s->tty, '/');
2148				cp = (cp == NULL) ? s->tty : cp + 1;
2149			} else
2150				cp = s->tty + 5;
2151
2152			if (buf[0] != '\0')
2153				strlcat(buf, ",", sizeof buf);
2154			strlcat(buf, cp, sizeof buf);
2155		}
2156	}
2157	if (buf[0] == '\0')
2158		strlcpy(buf, "notty", sizeof buf);
2159	return buf;
2160}
2161
2162void
2163session_proctitle(Session *s)
2164{
2165	if (s->pw == NULL)
2166		error("no user for session %d", s->self);
2167	else
2168		setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
2169}
2170
2171int
2172session_setup_x11fwd(Session *s)
2173{
2174	struct stat st;
2175	char display[512], auth_display[512];
2176	char hostname[MAXHOSTNAMELEN];
2177
2178	if (no_x11_forwarding_flag) {
2179		packet_send_debug("X11 forwarding disabled in user configuration file.");
2180		return 0;
2181	}
2182	if (!options.x11_forwarding) {
2183		debug("X11 forwarding disabled in server configuration file.");
2184		return 0;
2185	}
2186	if (!options.xauth_location ||
2187	    (stat(options.xauth_location, &st) == -1)) {
2188		packet_send_debug("No xauth program; cannot forward with spoofing.");
2189		return 0;
2190	}
2191	if (options.use_login) {
2192		packet_send_debug("X11 forwarding disabled; "
2193		    "not compatible with UseLogin=yes.");
2194		return 0;
2195	}
2196	if (s->display != NULL) {
2197		debug("X11 display already set.");
2198		return 0;
2199	}
2200	if (x11_create_display_inet(options.x11_display_offset,
2201	    options.x11_use_localhost, s->single_connection,
2202	    &s->display_number) == -1) {
2203		debug("x11_create_display_inet failed.");
2204		return 0;
2205	}
2206
2207	/* Set up a suitable value for the DISPLAY variable. */
2208	if (gethostname(hostname, sizeof(hostname)) < 0)
2209		fatal("gethostname: %.100s", strerror(errno));
2210	/*
2211	 * auth_display must be used as the displayname when the
2212	 * authorization entry is added with xauth(1).  This will be
2213	 * different than the DISPLAY string for localhost displays.
2214	 */
2215	if (options.x11_use_localhost) {
2216		snprintf(display, sizeof display, "localhost:%u.%u",
2217		    s->display_number, s->screen);
2218		snprintf(auth_display, sizeof auth_display, "unix:%u.%u",
2219		    s->display_number, s->screen);
2220		s->display = xstrdup(display);
2221		s->auth_display = xstrdup(auth_display);
2222	} else {
2223#ifdef IPADDR_IN_DISPLAY
2224		struct hostent *he;
2225		struct in_addr my_addr;
2226
2227		he = gethostbyname(hostname);
2228		if (he == NULL) {
2229			error("Can't get IP address for X11 DISPLAY.");
2230			packet_send_debug("Can't get IP address for X11 DISPLAY.");
2231			return 0;
2232		}
2233		memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr));
2234		snprintf(display, sizeof display, "%.50s:%u.%u", inet_ntoa(my_addr),
2235		    s->display_number, s->screen);
2236#else
2237		snprintf(display, sizeof display, "%.400s:%u.%u", hostname,
2238		    s->display_number, s->screen);
2239#endif
2240		s->display = xstrdup(display);
2241		s->auth_display = xstrdup(display);
2242	}
2243
2244	return 1;
2245}
2246
2247static void
2248do_authenticated2(Authctxt *authctxt)
2249{
2250	server_loop2(authctxt);
2251}
2252
2253void
2254do_cleanup(Authctxt *authctxt)
2255{
2256	static int called = 0;
2257
2258	debug("do_cleanup");
2259
2260	/* no cleanup if we're in the child for login shell */
2261	if (is_child)
2262		return;
2263
2264	/* avoid double cleanup */
2265	if (called)
2266		return;
2267	called = 1;
2268
2269	if (authctxt == NULL)
2270		return;
2271#ifdef KRB5
2272	if (options.kerberos_ticket_cleanup &&
2273	    authctxt->krb5_ctx)
2274		krb5_cleanup_proc(authctxt);
2275#endif
2276
2277#ifdef GSSAPI
2278	if (compat20 && options.gss_cleanup_creds)
2279		ssh_gssapi_cleanup_creds();
2280#endif
2281
2282#ifdef USE_PAM
2283	if (options.use_pam) {
2284		sshpam_cleanup();
2285		sshpam_thread_cleanup();
2286	}
2287#endif
2288
2289	/* remove agent socket */
2290	auth_sock_cleanup_proc(authctxt->pw);
2291
2292	/*
2293	 * Cleanup ptys/utmp only if privsep is disabled,
2294	 * or if running in monitor.
2295	 */
2296	if (!use_privsep || mm_is_monitor())
2297		session_destroy_all(session_pty_cleanup2);
2298}
2299