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1/* $OpenBSD: session.c,v 1.230 2008/02/22 05:58:56 djm Exp $ */
2/*
3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
4 * All rights reserved
5 *
6 * As far as I am concerned, the code I have written for this software
7 * can be used freely for any purpose. Any derived versions of this
8 * software must be clearly marked as such, and if the derived work is
9 * incompatible with the protocol description in the RFC file, it must be
10 * called by a name other than "ssh" or "Secure Shell".
11 *
12 * SSH2 support by Markus Friedl.
13 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
14 *
15 * Redistribution and use in source and binary forms, with or without
16 * modification, are permitted provided that the following conditions
17 * are met:
18 * 1. Redistributions of source code must retain the above copyright
19 * notice, this list of conditions and the following disclaimer.
20 * 2. Redistributions in binary form must reproduce the above copyright
21 * notice, this list of conditions and the following disclaimer in the
22 * documentation and/or other materials provided with the distribution.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
25 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
26 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
27 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
28 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
29 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
30 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
31 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
32 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
33 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
34 */
35
36#include "includes.h"
37
38#include <sys/types.h>
39#include <sys/param.h>
40#ifdef HAVE_SYS_STAT_H
41# include <sys/stat.h>
42#endif
43#include <sys/socket.h>
44#include <sys/un.h>
45#include <sys/wait.h>
46
47#include <arpa/inet.h>
48
49#include <errno.h>
50#include <grp.h>
51#ifdef HAVE_PATHS_H
52#include <paths.h>
53#endif
54#include <pwd.h>
55#include <signal.h>
56#include <stdarg.h>
57#include <stdio.h>
58#include <stdlib.h>
59#include <string.h>
60#include <unistd.h>
61
62#include "xmalloc.h"
63#include "ssh.h"
64#include "ssh1.h"
65#include "ssh2.h"
66#include "sshpty.h"
67#include "packet.h"
68#include "buffer.h"
69#include "match.h"
70#include "uidswap.h"
71#include "compat.h"
72#include "channels.h"
73#include "key.h"
74#include "cipher.h"
75#ifdef GSSAPI
76#include "ssh-gss.h"
77#endif
78#include "hostfile.h"
79#include "auth.h"
80#include "auth-options.h"
81#include "pathnames.h"
82#include "log.h"
83#include "servconf.h"
84#include "sshlogin.h"
85#include "serverloop.h"
86#include "canohost.h"
87#include "misc.h"
88#include "session.h"
89#include "kex.h"
90#include "monitor_wrap.h"
91#include "sftp.h"
92
93#if defined(KRB5) && defined(USE_AFS)
94#include <kafs.h>
95#endif
96
97/* func */
98
99Session *session_new(void);
100void session_set_fds(Session *, int, int, int);
101void session_pty_cleanup(Session *);
102void session_proctitle(Session *);
103int session_setup_x11fwd(Session *);
104void do_exec_pty(Session *, const char *);
105void do_exec_no_pty(Session *, const char *);
106void do_exec(Session *, const char *);
107void do_login(Session *, const char *);
108#ifdef LOGIN_NEEDS_UTMPX
109static void do_pre_login(Session *s);
110#endif
111void do_child(Session *, const char *);
112void do_motd(void);
113int check_quietlogin(Session *, const char *);
114
115static void do_authenticated1(Authctxt *);
116static void do_authenticated2(Authctxt *);
117
118static int session_pty_req(Session *);
119
120/* import */
121extern ServerOptions options;
122extern char *__progname;
123extern int log_stderr;
124extern int debug_flag;
125extern u_int utmp_len;
126extern int startup_pipe;
127extern void destroy_sensitive_data(void);
128extern Buffer loginmsg;
129
130/* original command from peer. */
131const char *original_command = NULL;
132
133/* data */
134#define MAX_SESSIONS 20
135Session sessions[MAX_SESSIONS];
136
137#define SUBSYSTEM_NONE 0
138#define SUBSYSTEM_EXT 1
139#define SUBSYSTEM_INT_SFTP 2
140
141#ifdef HAVE_LOGIN_CAP
142login_cap_t *lc;
143#endif
144
145static int is_child = 0;
146
147/* Name and directory of socket for authentication agent forwarding. */
148static char *auth_sock_name = NULL;
149static char *auth_sock_dir = NULL;
150
151/* removes the agent forwarding socket */
152
153static void
154auth_sock_cleanup_proc(struct passwd *pw)
155{
156 if (auth_sock_name != NULL) {
157 temporarily_use_uid(pw);
158 unlink(auth_sock_name);
159 rmdir(auth_sock_dir);
160 auth_sock_name = NULL;
161 restore_uid();
162 }
163}
164
165static int
166auth_input_request_forwarding(struct passwd * pw)
167{
168 Channel *nc;
169 int sock;
170 struct sockaddr_un sunaddr;
171
172 if (auth_sock_name != NULL) {
173 error("authentication forwarding requested twice.");
174 return 0;
175 }
176
177 /* Temporarily drop privileged uid for mkdir/bind. */
178 temporarily_use_uid(pw);
179
180 /* Allocate a buffer for the socket name, and format the name. */
181 auth_sock_name = xmalloc(MAXPATHLEN);
182 auth_sock_dir = xmalloc(MAXPATHLEN);
183 strlcpy(auth_sock_dir, "/tmp/ssh-XXXXXXXXXX", MAXPATHLEN);
184
185 /* Create private directory for socket */
186 if (mkdtemp(auth_sock_dir) == NULL) {
187 packet_send_debug("Agent forwarding disabled: "
188 "mkdtemp() failed: %.100s", strerror(errno));
189 restore_uid();
190 xfree(auth_sock_name);
191 xfree(auth_sock_dir);
192 auth_sock_name = NULL;
193 auth_sock_dir = NULL;
194 return 0;
195 }
196 snprintf(auth_sock_name, MAXPATHLEN, "%s/agent.%ld",
197 auth_sock_dir, (long) getpid());
198
199 /* Create the socket. */
200 sock = socket(AF_UNIX, SOCK_STREAM, 0);
201 if (sock < 0)
202 packet_disconnect("socket: %.100s", strerror(errno));
203
204 /* Bind it to the name. */
205 memset(&sunaddr, 0, sizeof(sunaddr));
206 sunaddr.sun_family = AF_UNIX;
207 strlcpy(sunaddr.sun_path, auth_sock_name, sizeof(sunaddr.sun_path));
208
209 if (bind(sock, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) < 0)
210 packet_disconnect("bind: %.100s", strerror(errno));
211
212 /* Restore the privileged uid. */
213 restore_uid();
214
215 /* Start listening on the socket. */
216 if (listen(sock, SSH_LISTEN_BACKLOG) < 0)
217 packet_disconnect("listen: %.100s", strerror(errno));
218
219 /* Allocate a channel for the authentication agent socket. */
220 nc = channel_new("auth socket",
221 SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1,
222 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
223 0, "auth socket", 1);
224 strlcpy(nc->path, auth_sock_name, sizeof(nc->path));
225 return 1;
226}
227
228static void
229display_loginmsg(void)
230{
231 if (buffer_len(&loginmsg) > 0) {
232 buffer_append(&loginmsg, "\0", 1);
233 printf("%s", (char *)buffer_ptr(&loginmsg));
234 buffer_clear(&loginmsg);
235 }
236}
237
238void
239do_authenticated(Authctxt *authctxt)
240{
241 setproctitle("%s", authctxt->pw->pw_name);
242
243 /* setup the channel layer */
244 if (!no_port_forwarding_flag && options.allow_tcp_forwarding)
245 channel_permit_all_opens();
246
247 if (compat20)
248 do_authenticated2(authctxt);
249 else
250 do_authenticated1(authctxt);
251
252 do_cleanup(authctxt);
253}
254
255/*
256 * Prepares for an interactive session. This is called after the user has
257 * been successfully authenticated. During this message exchange, pseudo
258 * terminals are allocated, X11, TCP/IP, and authentication agent forwardings
259 * are requested, etc.
260 */
261static void
262do_authenticated1(Authctxt *authctxt)
263{
264 Session *s;
265 char *command;
266 int success, type, screen_flag;
267 int enable_compression_after_reply = 0;
268 u_int proto_len, data_len, dlen, compression_level = 0;
269
270 s = session_new();
271 if (s == NULL) {
272 error("no more sessions");
273 return;
274 }
275 s->authctxt = authctxt;
276 s->pw = authctxt->pw;
277
278 /*
279 * We stay in this loop until the client requests to execute a shell
280 * or a command.
281 */
282 for (;;) {
283 success = 0;
284
285 /* Get a packet from the client. */
286 type = packet_read();
287
288 /* Process the packet. */
289 switch (type) {
290 case SSH_CMSG_REQUEST_COMPRESSION:
291 compression_level = packet_get_int();
292 packet_check_eom();
293 if (compression_level < 1 || compression_level > 9) {
294 packet_send_debug("Received invalid compression level %d.",
295 compression_level);
296 break;
297 }
298 if (options.compression == COMP_NONE) {
299 debug2("compression disabled");
300 break;
301 }
302 /* Enable compression after we have responded with SUCCESS. */
303 enable_compression_after_reply = 1;
304 success = 1;
305 break;
306
307 case SSH_CMSG_REQUEST_PTY:
308 success = session_pty_req(s);
309 break;
310
311 case SSH_CMSG_X11_REQUEST_FORWARDING:
312 s->auth_proto = packet_get_string(&proto_len);
313 s->auth_data = packet_get_string(&data_len);
314
315 screen_flag = packet_get_protocol_flags() &
316 SSH_PROTOFLAG_SCREEN_NUMBER;
317 debug2("SSH_PROTOFLAG_SCREEN_NUMBER: %d", screen_flag);
318
319 if (packet_remaining() == 4) {
320 if (!screen_flag)
321 debug2("Buggy client: "
322 "X11 screen flag missing");
323 s->screen = packet_get_int();
324 } else {
325 s->screen = 0;
326 }
327 packet_check_eom();
328 success = session_setup_x11fwd(s);
329 if (!success) {
330 xfree(s->auth_proto);
331 xfree(s->auth_data);
332 s->auth_proto = NULL;
333 s->auth_data = NULL;
334 }
335 break;
336
337 case SSH_CMSG_AGENT_REQUEST_FORWARDING:
338 if (no_agent_forwarding_flag || compat13) {
339 debug("Authentication agent forwarding not permitted for this authentication.");
340 break;
341 }
342 debug("Received authentication agent forwarding request.");
343 success = auth_input_request_forwarding(s->pw);
344 break;
345
346 case SSH_CMSG_PORT_FORWARD_REQUEST:
347 if (no_port_forwarding_flag) {
348 debug("Port forwarding not permitted for this authentication.");
349 break;
350 }
351 if (!options.allow_tcp_forwarding) {
352 debug("Port forwarding not permitted.");
353 break;
354 }
355 debug("Received TCP/IP port forwarding request.");
356 if (channel_input_port_forward_request(s->pw->pw_uid == 0,
357 options.gateway_ports) < 0) {
358 debug("Port forwarding failed.");
359 break;
360 }
361 success = 1;
362 break;
363
364 case SSH_CMSG_MAX_PACKET_SIZE:
365 if (packet_set_maxsize(packet_get_int()) > 0)
366 success = 1;
367 break;
368
369 case SSH_CMSG_EXEC_SHELL:
370 case SSH_CMSG_EXEC_CMD:
371 if (type == SSH_CMSG_EXEC_CMD) {
372 command = packet_get_string(&dlen);
373 debug("Exec command '%.500s'", command);
374 do_exec(s, command);
375 xfree(command);
376 } else {
377 do_exec(s, NULL);
378 }
379 packet_check_eom();
380 session_close(s);
381 return;
382
383 default:
384 /*
385 * Any unknown messages in this phase are ignored,
386 * and a failure message is returned.
387 */
388 logit("Unknown packet type received after authentication: %d", type);
389 }
390 packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE);
391 packet_send();
392 packet_write_wait();
393
394 /* Enable compression now that we have replied if appropriate. */
395 if (enable_compression_after_reply) {
396 enable_compression_after_reply = 0;
397 packet_start_compression(compression_level);
398 }
399 }
400}
401
402/*
403 * This is called to fork and execute a command when we have no tty. This
404 * will call do_child from the child, and server_loop from the parent after
405 * setting up file descriptors and such.
406 */
407void
408do_exec_no_pty(Session *s, const char *command)
409{
410 pid_t pid;
411
412#ifdef USE_PIPES
413 int pin[2], pout[2], perr[2];
414 /* Allocate pipes for communicating with the program. */
415 if (pipe(pin) < 0 || pipe(pout) < 0 || pipe(perr) < 0)
416 packet_disconnect("Could not create pipes: %.100s",
417 strerror(errno));
418#else /* USE_PIPES */
419 int inout[2], err[2];
420 /* Uses socket pairs to communicate with the program. */
421 if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0 ||
422 socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0)
423 packet_disconnect("Could not create socket pairs: %.100s",
424 strerror(errno));
425#endif /* USE_PIPES */
426 if (s == NULL)
427 fatal("do_exec_no_pty: no session");
428
429 session_proctitle(s);
430
431 /* Fork the child. */
432 if ((pid = fork()) == 0) {
433 is_child = 1;
434
435 /* Child. Reinitialize the log since the pid has changed. */
436 log_init(__progname, options.log_level, options.log_facility, log_stderr);
437
438 /*
439 * Create a new session and process group since the 4.4BSD
440 * setlogin() affects the entire process group.
441 */
442 if (setsid() < 0)
443 error("setsid failed: %.100s", strerror(errno));
444
445#ifdef USE_PIPES
446 /*
447 * Redirect stdin. We close the parent side of the socket
448 * pair, and make the child side the standard input.
449 */
450 close(pin[1]);
451 if (dup2(pin[0], 0) < 0)
452 perror("dup2 stdin");
453 close(pin[0]);
454
455 /* Redirect stdout. */
456 close(pout[0]);
457 if (dup2(pout[1], 1) < 0)
458 perror("dup2 stdout");
459 close(pout[1]);
460
461 /* Redirect stderr. */
462 close(perr[0]);
463 if (dup2(perr[1], 2) < 0)
464 perror("dup2 stderr");
465 close(perr[1]);
466#else /* USE_PIPES */
467 /*
468 * Redirect stdin, stdout, and stderr. Stdin and stdout will
469 * use the same socket, as some programs (particularly rdist)
470 * seem to depend on it.
471 */
472 close(inout[1]);
473 close(err[1]);
474 if (dup2(inout[0], 0) < 0) /* stdin */
475 perror("dup2 stdin");
476 if (dup2(inout[0], 1) < 0) /* stdout. Note: same socket as stdin. */
477 perror("dup2 stdout");
478 if (dup2(err[0], 2) < 0) /* stderr */
479 perror("dup2 stderr");
480#endif /* USE_PIPES */
481
482#ifdef _UNICOS
483 cray_init_job(s->pw); /* set up cray jid and tmpdir */
484#endif
485
486 /* Do processing for the child (exec command etc). */
487 do_child(s, command);
488 /* NOTREACHED */
489 }
490#ifdef _UNICOS
491 signal(WJSIGNAL, cray_job_termination_handler);
492#endif /* _UNICOS */
493#ifdef HAVE_CYGWIN
494 if (is_winnt)
495 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
496#endif
497 if (pid < 0)
498 packet_disconnect("fork failed: %.100s", strerror(errno));
499 s->pid = pid;
500 /* Set interactive/non-interactive mode. */
501 packet_set_interactive(s->display != NULL);
502#ifdef USE_PIPES
503 /* We are the parent. Close the child sides of the pipes. */
504 close(pin[0]);
505 close(pout[1]);
506 close(perr[1]);
507
508 if (compat20) {
509 if (s->is_subsystem) {
510 close(perr[0]);
511 perr[0] = -1;
512 }
513 session_set_fds(s, pin[1], pout[0], perr[0]);
514 } else {
515 /* Enter the interactive session. */
516 server_loop(pid, pin[1], pout[0], perr[0]);
517 /* server_loop has closed pin[1], pout[0], and perr[0]. */
518 }
519#else /* USE_PIPES */
520 /* We are the parent. Close the child sides of the socket pairs. */
521 close(inout[0]);
522 close(err[0]);
523
524 /*
525 * Clear loginmsg, since it's the child's responsibility to display
526 * it to the user, otherwise multiple sessions may accumulate
527 * multiple copies of the login messages.
528 */
529 buffer_clear(&loginmsg);
530
531 /*
532 * Enter the interactive session. Note: server_loop must be able to
533 * handle the case that fdin and fdout are the same.
534 */
535 if (compat20) {
536 session_set_fds(s, inout[1], inout[1], s->is_subsystem ? -1 : err[1]);
537 } else {
538 server_loop(pid, inout[1], inout[1], err[1]);
539 /* server_loop has closed inout[1] and err[1]. */
540 }
541#endif /* USE_PIPES */
542}
543
544/*
545 * This is called to fork and execute a command when we have a tty. This
546 * will call do_child from the child, and server_loop from the parent after
547 * setting up file descriptors, controlling tty, updating wtmp, utmp,
548 * lastlog, and other such operations.
549 */
550void
551do_exec_pty(Session *s, const char *command)
552{
553 int fdout, ptyfd, ttyfd, ptymaster;
554 pid_t pid;
555
556 if (s == NULL)
557 fatal("do_exec_pty: no session");
558 ptyfd = s->ptyfd;
559 ttyfd = s->ttyfd;
560
561 /* Fork the child. */
562 if ((pid = fork()) == 0) {
563 is_child = 1;
564
565 /* Child. Reinitialize the log because the pid has changed. */
566 log_init(__progname, options.log_level, options.log_facility, log_stderr);
567 /* Close the master side of the pseudo tty. */
568 close(ptyfd);
569
570 /* Make the pseudo tty our controlling tty. */
571 pty_make_controlling_tty(&ttyfd, s->tty);
572
573 /* Redirect stdin/stdout/stderr from the pseudo tty. */
574 if (dup2(ttyfd, 0) < 0)
575 error("dup2 stdin: %s", strerror(errno));
576 if (dup2(ttyfd, 1) < 0)
577 error("dup2 stdout: %s", strerror(errno));
578 if (dup2(ttyfd, 2) < 0)
579 error("dup2 stderr: %s", strerror(errno));
580
581 /* Close the extra descriptor for the pseudo tty. */
582 close(ttyfd);
583
584 /* record login, etc. similar to login(1) */
585#ifndef HAVE_OSF_SIA
586 if (!(options.use_login && command == NULL)) {
587#ifdef _UNICOS
588 cray_init_job(s->pw); /* set up cray jid and tmpdir */
589#endif /* _UNICOS */
590 do_login(s, command);
591 }
592# ifdef LOGIN_NEEDS_UTMPX
593 else
594 do_pre_login(s);
595# endif
596#endif
597
598 /* Do common processing for the child, such as execing the command. */
599 do_child(s, command);
600 /* NOTREACHED */
601 }
602#ifdef _UNICOS
603 signal(WJSIGNAL, cray_job_termination_handler);
604#endif /* _UNICOS */
605#ifdef HAVE_CYGWIN
606 if (is_winnt)
607 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
608#endif
609 if (pid < 0)
610 packet_disconnect("fork failed: %.100s", strerror(errno));
611 s->pid = pid;
612
613 /* Parent. Close the slave side of the pseudo tty. */
614 close(ttyfd);
615
616 /*
617 * Create another descriptor of the pty master side for use as the
618 * standard input. We could use the original descriptor, but this
619 * simplifies code in server_loop. The descriptor is bidirectional.
620 */
621 fdout = dup(ptyfd);
622 if (fdout < 0)
623 packet_disconnect("dup #1 failed: %.100s", strerror(errno));
624
625 /* we keep a reference to the pty master */
626 ptymaster = dup(ptyfd);
627 if (ptymaster < 0)
628 packet_disconnect("dup #2 failed: %.100s", strerror(errno));
629 s->ptymaster = ptymaster;
630
631 /* Enter interactive session. */
632 packet_set_interactive(1);
633 if (compat20) {
634 session_set_fds(s, ptyfd, fdout, -1);
635 } else {
636 server_loop(pid, ptyfd, fdout, -1);
637 /* server_loop _has_ closed ptyfd and fdout. */
638 }
639}
640
641#ifdef LOGIN_NEEDS_UTMPX
642static void
643do_pre_login(Session *s)
644{
645 socklen_t fromlen;
646 struct sockaddr_storage from;
647 pid_t pid = getpid();
648
649 /*
650 * Get IP address of client. If the connection is not a socket, let
651 * the address be 0.0.0.0.
652 */
653 memset(&from, 0, sizeof(from));
654 fromlen = sizeof(from);
655 if (packet_connection_is_on_socket()) {
656 if (getpeername(packet_get_connection_in(),
657 (struct sockaddr *)&from, &fromlen) < 0) {
658 debug("getpeername: %.100s", strerror(errno));
659 cleanup_exit(255);
660 }
661 }
662
663 record_utmp_only(pid, s->tty, s->pw->pw_name,
664 get_remote_name_or_ip(utmp_len, options.use_dns),
665 (struct sockaddr *)&from, fromlen);
666}
667#endif
668
669/*
670 * This is called to fork and execute a command. If another command is
671 * to be forced, execute that instead.
672 */
673void
674do_exec(Session *s, const char *command)
675{
676 if (options.adm_forced_command) {
677 original_command = command;
678 command = options.adm_forced_command;
679 if (strcmp(INTERNAL_SFTP_NAME, command) == 0)
680 s->is_subsystem = SUBSYSTEM_INT_SFTP;
681 else if (s->is_subsystem)
682 s->is_subsystem = SUBSYSTEM_EXT;
683 debug("Forced command (config) '%.900s'", command);
684 } else if (forced_command) {
685 original_command = command;
686 command = forced_command;
687 if (strcmp(INTERNAL_SFTP_NAME, command) == 0)
688 s->is_subsystem = SUBSYSTEM_INT_SFTP;
689 else if (s->is_subsystem)
690 s->is_subsystem = SUBSYSTEM_EXT;
691 debug("Forced command (key option) '%.900s'", command);
692 }
693
694#ifdef SSH_AUDIT_EVENTS
695 if (command != NULL)
696 PRIVSEP(audit_run_command(command));
697 else if (s->ttyfd == -1) {
698 char *shell = s->pw->pw_shell;
699
700 if (shell[0] == '\0') /* empty shell means /bin/sh */
701 shell =_PATH_BSHELL;
702 PRIVSEP(audit_run_command(shell));
703 }
704#endif
705 if (s->ttyfd != -1)
706 do_exec_pty(s, command);
707 else
708 do_exec_no_pty(s, command);
709
710 original_command = NULL;
711
712 /*
713 * Clear loginmsg: it's the child's responsibility to display
714 * it to the user, otherwise multiple sessions may accumulate
715 * multiple copies of the login messages.
716 */
717 buffer_clear(&loginmsg);
718}
719
720/* administrative, login(1)-like work */
721void
722do_login(Session *s, const char *command)
723{
724 socklen_t fromlen;
725 struct sockaddr_storage from;
726 struct passwd * pw = s->pw;
727 pid_t pid = getpid();
728
729 /*
730 * Get IP address of client. If the connection is not a socket, let
731 * the address be 0.0.0.0.
732 */
733 memset(&from, 0, sizeof(from));
734 fromlen = sizeof(from);
735 if (packet_connection_is_on_socket()) {
736 if (getpeername(packet_get_connection_in(),
737 (struct sockaddr *) & from, &fromlen) < 0) {
738 debug("getpeername: %.100s", strerror(errno));
739 cleanup_exit(255);
740 }
741 }
742
743 /* Record that there was a login on that tty from the remote host. */
744 if (!use_privsep)
745 record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
746 get_remote_name_or_ip(utmp_len,
747 options.use_dns),
748 (struct sockaddr *)&from, fromlen);
749
750#ifdef USE_PAM
751 /*
752 * If password change is needed, do it now.
753 * This needs to occur before the ~/.hushlogin check.
754 */
755 if (options.use_pam && !use_privsep && s->authctxt->force_pwchange) {
756 display_loginmsg();
757 do_pam_chauthtok();
758 s->authctxt->force_pwchange = 0;
759 /* XXX - signal [net] parent to enable forwardings */
760 }
761#endif
762
763 if (check_quietlogin(s, command))
764 return;
765
766 display_loginmsg();
767
768 do_motd();
769}
770
771/*
772 * Display the message of the day.
773 */
774void
775do_motd(void)
776{
777 FILE *f;
778 char buf[256];
779
780 if (options.print_motd) {
781#ifdef HAVE_LOGIN_CAP
782 f = fopen(login_getcapstr(lc, "welcome", "/etc/motd",
783 "/etc/motd"), "r");
784#else
785 f = fopen("/etc/motd", "r");
786#endif
787 if (f) {
788 while (fgets(buf, sizeof(buf), f))
789 fputs(buf, stdout);
790 fclose(f);
791 }
792 }
793}
794
795
796/*
797 * Check for quiet login, either .hushlogin or command given.
798 */
799int
800check_quietlogin(Session *s, const char *command)
801{
802 char buf[256];
803 struct passwd *pw = s->pw;
804 struct stat st;
805
806 /* Return 1 if .hushlogin exists or a command given. */
807 if (command != NULL)
808 return 1;
809 snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
810#ifdef HAVE_LOGIN_CAP
811 if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
812 return 1;
813#else
814 if (stat(buf, &st) >= 0)
815 return 1;
816#endif
817 return 0;
818}
819
820/*
821 * Sets the value of the given variable in the environment. If the variable
822 * already exists, its value is overriden.
823 */
824void
825child_set_env(char ***envp, u_int *envsizep, const char *name,
826 const char *value)
827{
828 char **env;
829 u_int envsize;
830 u_int i, namelen;
831
832 /*
833 * If we're passed an uninitialized list, allocate a single null
834 * entry before continuing.
835 */
836 if (*envp == NULL && *envsizep == 0) {
837 *envp = xmalloc(sizeof(char *));
838 *envp[0] = NULL;
839 *envsizep = 1;
840 }
841
842 /*
843 * Find the slot where the value should be stored. If the variable
844 * already exists, we reuse the slot; otherwise we append a new slot
845 * at the end of the array, expanding if necessary.
846 */
847 env = *envp;
848 namelen = strlen(name);
849 for (i = 0; env[i]; i++)
850 if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
851 break;
852 if (env[i]) {
853 /* Reuse the slot. */
854 xfree(env[i]);
855 } else {
856 /* New variable. Expand if necessary. */
857 envsize = *envsizep;
858 if (i >= envsize - 1) {
859 if (envsize >= 1000)
860 fatal("child_set_env: too many env vars");
861 envsize += 50;
862 env = (*envp) = xrealloc(env, envsize, sizeof(char *));
863 *envsizep = envsize;
864 }
865 /* Need to set the NULL pointer at end of array beyond the new slot. */
866 env[i + 1] = NULL;
867 }
868
869 /* Allocate space and format the variable in the appropriate slot. */
870 env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
871 snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
872}
873
874/*
875 * Reads environment variables from the given file and adds/overrides them
876 * into the environment. If the file does not exist, this does nothing.
877 * Otherwise, it must consist of empty lines, comments (line starts with '#')
878 * and assignments of the form name=value. No other forms are allowed.
879 */
880static void
881read_environment_file(char ***env, u_int *envsize,
882 const char *filename)
883{
884 FILE *f;
885 char buf[4096];
886 char *cp, *value;
887 u_int lineno = 0;
888
889 f = fopen(filename, "r");
890 if (!f)
891 return;
892
893 while (fgets(buf, sizeof(buf), f)) {
894 if (++lineno > 1000)
895 fatal("Too many lines in environment file %s", filename);
896 for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
897 ;
898 if (!*cp || *cp == '#' || *cp == '\n')
899 continue;
900
901 cp[strcspn(cp, "\n")] = '\0';
902
903 value = strchr(cp, '=');
904 if (value == NULL) {
905 fprintf(stderr, "Bad line %u in %.100s\n", lineno,
906 filename);
907 continue;
908 }
909 /*
910 * Replace the equals sign by nul, and advance value to
911 * the value string.
912 */
913 *value = '\0';
914 value++;
915 child_set_env(env, envsize, cp, value);
916 }
917 fclose(f);
918}
919
920#ifdef HAVE_ETC_DEFAULT_LOGIN
921/*
922 * Return named variable from specified environment, or NULL if not present.
923 */
924static char *
925child_get_env(char **env, const char *name)
926{
927 int i;
928 size_t len;
929
930 len = strlen(name);
931 for (i=0; env[i] != NULL; i++)
932 if (strncmp(name, env[i], len) == 0 && env[i][len] == '=')
933 return(env[i] + len + 1);
934 return NULL;
935}
936
937/*
938 * Read /etc/default/login.
939 * We pick up the PATH (or SUPATH for root) and UMASK.
940 */
941static void
942read_etc_default_login(char ***env, u_int *envsize, uid_t uid)
943{
944 char **tmpenv = NULL, *var;
945 u_int i, tmpenvsize = 0;
946 u_long mask;
947
948 /*
949 * We don't want to copy the whole file to the child's environment,
950 * so we use a temporary environment and copy the variables we're
951 * interested in.
952 */
953 read_environment_file(&tmpenv, &tmpenvsize, "/etc/default/login");
954
955 if (tmpenv == NULL)
956 return;
957
958 if (uid == 0)
959 var = child_get_env(tmpenv, "SUPATH");
960 else
961 var = child_get_env(tmpenv, "PATH");
962 if (var != NULL)
963 child_set_env(env, envsize, "PATH", var);
964
965 if ((var = child_get_env(tmpenv, "UMASK")) != NULL)
966 if (sscanf(var, "%5lo", &mask) == 1)
967 umask((mode_t)mask);
968
969 for (i = 0; tmpenv[i] != NULL; i++)
970 xfree(tmpenv[i]);
971 xfree(tmpenv);
972}
973#endif /* HAVE_ETC_DEFAULT_LOGIN */
974
975void
976copy_environment(char **source, char ***env, u_int *envsize)
977{
978 char *var_name, *var_val;
979 int i;
980
981 if (source == NULL)
982 return;
983
984 for(i = 0; source[i] != NULL; i++) {
985 var_name = xstrdup(source[i]);
986 if ((var_val = strstr(var_name, "=")) == NULL) {
987 xfree(var_name);
988 continue;
989 }
990 *var_val++ = '\0';
991
992 debug3("Copy environment: %s=%s", var_name, var_val);
993 child_set_env(env, envsize, var_name, var_val);
994
995 xfree(var_name);
996 }
997}
998
999static char **
1000do_setup_env(Session *s, const char *shell)
1001{
1002 char buf[256];
1003 u_int i, envsize;
1004 char **env, *laddr;
1005 struct passwd *pw = s->pw;
1006#ifndef HAVE_LOGIN_CAP
1007 char *path = NULL;
1008#endif
1009
1010 /* Initialize the environment. */
1011 envsize = 100;
1012 env = xcalloc(envsize, sizeof(char *));
1013 env[0] = NULL;
1014
1015#ifdef HAVE_CYGWIN
1016 /*
1017 * The Windows environment contains some setting which are
1018 * important for a running system. They must not be dropped.
1019 */
1020 {
1021 char **p;
1022
1023 p = fetch_windows_environment();
1024 copy_environment(p, &env, &envsize);
1025 free_windows_environment(p);
1026 }
1027#endif
1028
1029#ifdef GSSAPI
1030 /* Allow any GSSAPI methods that we've used to alter
1031 * the childs environment as they see fit
1032 */
1033 ssh_gssapi_do_child(&env, &envsize);
1034#endif
1035
1036 if (!options.use_login) {
1037 /* Set basic environment. */
1038 for (i = 0; i < s->num_env; i++)
1039 child_set_env(&env, &envsize, s->env[i].name,
1040 s->env[i].val);
1041
1042 child_set_env(&env, &envsize, "USER", pw->pw_name);
1043 child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
1044#ifdef _AIX
1045 child_set_env(&env, &envsize, "LOGIN", pw->pw_name);
1046#endif
1047 child_set_env(&env, &envsize, "HOME", pw->pw_dir);
1048#ifdef HAVE_LOGIN_CAP
1049 if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETPATH) < 0)
1050 child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
1051 else
1052 child_set_env(&env, &envsize, "PATH", getenv("PATH"));
1053#else /* HAVE_LOGIN_CAP */
1054# ifndef HAVE_CYGWIN
1055 /*
1056 * There's no standard path on Windows. The path contains
1057 * important components pointing to the system directories,
1058 * needed for loading shared libraries. So the path better
1059 * remains intact here.
1060 */
1061# ifdef HAVE_ETC_DEFAULT_LOGIN
1062 read_etc_default_login(&env, &envsize, pw->pw_uid);
1063 path = child_get_env(env, "PATH");
1064# endif /* HAVE_ETC_DEFAULT_LOGIN */
1065 if (path == NULL || *path == '\0') {
1066 child_set_env(&env, &envsize, "PATH",
1067 s->pw->pw_uid == 0 ?
1068 SUPERUSER_PATH : _PATH_STDPATH);
1069 }
1070# endif /* HAVE_CYGWIN */
1071#endif /* HAVE_LOGIN_CAP */
1072
1073 snprintf(buf, sizeof buf, "%.200s/%.50s",
1074 _PATH_MAILDIR, pw->pw_name);
1075 child_set_env(&env, &envsize, "MAIL", buf);
1076
1077 /* Normal systems set SHELL by default. */
1078 child_set_env(&env, &envsize, "SHELL", shell);
1079 }
1080 if (getenv("TZ"))
1081 child_set_env(&env, &envsize, "TZ", getenv("TZ"));
1082
1083 /* Set custom environment options from RSA authentication. */
1084 if (!options.use_login) {
1085 while (custom_environment) {
1086 struct envstring *ce = custom_environment;
1087 char *str = ce->s;
1088
1089 for (i = 0; str[i] != '=' && str[i]; i++)
1090 ;
1091 if (str[i] == '=') {
1092 str[i] = 0;
1093 child_set_env(&env, &envsize, str, str + i + 1);
1094 }
1095 custom_environment = ce->next;
1096 xfree(ce->s);
1097 xfree(ce);
1098 }
1099 }
1100
1101 /* SSH_CLIENT deprecated */
1102 snprintf(buf, sizeof buf, "%.50s %d %d",
1103 get_remote_ipaddr(), get_remote_port(), get_local_port());
1104 child_set_env(&env, &envsize, "SSH_CLIENT", buf);
1105
1106 laddr = get_local_ipaddr(packet_get_connection_in());
1107 snprintf(buf, sizeof buf, "%.50s %d %.50s %d",
1108 get_remote_ipaddr(), get_remote_port(), laddr, get_local_port());
1109 xfree(laddr);
1110 child_set_env(&env, &envsize, "SSH_CONNECTION", buf);
1111
1112 if (s->ttyfd != -1)
1113 child_set_env(&env, &envsize, "SSH_TTY", s->tty);
1114 if (s->term)
1115 child_set_env(&env, &envsize, "TERM", s->term);
1116 if (s->display)
1117 child_set_env(&env, &envsize, "DISPLAY", s->display);
1118 if (original_command)
1119 child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
1120 original_command);
1121
1122#ifdef _UNICOS
1123 if (cray_tmpdir[0] != '\0')
1124 child_set_env(&env, &envsize, "TMPDIR", cray_tmpdir);
1125#endif /* _UNICOS */
1126
1127 /*
1128 * Since we clear KRB5CCNAME at startup, if it's set now then it
1129 * must have been set by a native authentication method (eg AIX or
1130 * SIA), so copy it to the child.
1131 */
1132 {
1133 char *cp;
1134
1135 if ((cp = getenv("KRB5CCNAME")) != NULL)
1136 child_set_env(&env, &envsize, "KRB5CCNAME", cp);
1137 }
1138
1139#ifdef _AIX
1140 {
1141 char *cp;
1142
1143 if ((cp = getenv("AUTHSTATE")) != NULL)
1144 child_set_env(&env, &envsize, "AUTHSTATE", cp);
1145 read_environment_file(&env, &envsize, "/etc/environment");
1146 }
1147#endif
1148#ifdef KRB5
1149 if (s->authctxt->krb5_ccname)
1150 child_set_env(&env, &envsize, "KRB5CCNAME",
1151 s->authctxt->krb5_ccname);
1152#endif
1153#ifdef USE_PAM
1154 /*
1155 * Pull in any environment variables that may have
1156 * been set by PAM.
1157 */
1158 if (options.use_pam) {
1159 char **p;
1160
1161 p = fetch_pam_child_environment();
1162 copy_environment(p, &env, &envsize);
1163 free_pam_environment(p);
1164
1165 p = fetch_pam_environment();
1166 copy_environment(p, &env, &envsize);
1167 free_pam_environment(p);
1168 }
1169#endif /* USE_PAM */
1170
1171 if (auth_sock_name != NULL)
1172 child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
1173 auth_sock_name);
1174
1175 /* read $HOME/.ssh/environment. */
1176 if (options.permit_user_env && !options.use_login) {
1177 snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
1178 strcmp(pw->pw_dir, "/") ? pw->pw_dir : "");
1179 read_environment_file(&env, &envsize, buf);
1180 }
1181 if (debug_flag) {
1182 /* dump the environment */
1183 fprintf(stderr, "Environment:\n");
1184 for (i = 0; env[i]; i++)
1185 fprintf(stderr, " %.200s\n", env[i]);
1186 }
1187 return env;
1188}
1189
1190/*
1191 * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found
1192 * first in this order).
1193 */
1194static void
1195do_rc_files(Session *s, const char *shell)
1196{
1197 FILE *f = NULL;
1198 char cmd[1024];
1199 int do_xauth;
1200 struct stat st;
1201
1202 do_xauth =
1203 s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
1204
1205 /* ignore _PATH_SSH_USER_RC for subsystems */
1206 if (!s->is_subsystem && (stat(_PATH_SSH_USER_RC, &st) >= 0)) {
1207 snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
1208 shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
1209 if (debug_flag)
1210 fprintf(stderr, "Running %s\n", cmd);
1211 f = popen(cmd, "w");
1212 if (f) {
1213 if (do_xauth)
1214 fprintf(f, "%s %s\n", s->auth_proto,
1215 s->auth_data);
1216 pclose(f);
1217 } else
1218 fprintf(stderr, "Could not run %s\n",
1219 _PATH_SSH_USER_RC);
1220 } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
1221 if (debug_flag)
1222 fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
1223 _PATH_SSH_SYSTEM_RC);
1224 f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
1225 if (f) {
1226 if (do_xauth)
1227 fprintf(f, "%s %s\n", s->auth_proto,
1228 s->auth_data);
1229 pclose(f);
1230 } else
1231 fprintf(stderr, "Could not run %s\n",
1232 _PATH_SSH_SYSTEM_RC);
1233 } else if (do_xauth && options.xauth_location != NULL) {
1234 /* Add authority data to .Xauthority if appropriate. */
1235 if (debug_flag) {
1236 fprintf(stderr,
1237 "Running %.500s remove %.100s\n",
1238 options.xauth_location, s->auth_display);
1239 fprintf(stderr,
1240 "%.500s add %.100s %.100s %.100s\n",
1241 options.xauth_location, s->auth_display,
1242 s->auth_proto, s->auth_data);
1243 }
1244 snprintf(cmd, sizeof cmd, "%s -q -",
1245 options.xauth_location);
1246 f = popen(cmd, "w");
1247 if (f) {
1248 fprintf(f, "remove %s\n",
1249 s->auth_display);
1250 fprintf(f, "add %s %s %s\n",
1251 s->auth_display, s->auth_proto,
1252 s->auth_data);
1253 pclose(f);
1254 } else {
1255 fprintf(stderr, "Could not run %s\n",
1256 cmd);
1257 }
1258 }
1259}
1260
1261static void
1262do_nologin(struct passwd *pw)
1263{
1264 FILE *f = NULL;
1265 char buf[1024];
1266
1267#ifdef HAVE_LOGIN_CAP
1268 if (!login_getcapbool(lc, "ignorenologin", 0) && pw->pw_uid)
1269 f = fopen(login_getcapstr(lc, "nologin", _PATH_NOLOGIN,
1270 _PATH_NOLOGIN), "r");
1271#else
1272 if (pw->pw_uid)
1273 f = fopen(_PATH_NOLOGIN, "r");
1274#endif
1275 if (f) {
1276 /* /etc/nologin exists. Print its contents and exit. */
1277 logit("User %.100s not allowed because %s exists",
1278 pw->pw_name, _PATH_NOLOGIN);
1279 while (fgets(buf, sizeof(buf), f))
1280 fputs(buf, stderr);
1281 fclose(f);
1282 fflush(NULL);
1283 exit(254);
1284 }
1285}
1286
1287/*
1288 * Chroot into a directory after checking it for safety: all path components
1289 * must be root-owned directories with strict permissions.
1290 */
1291static void
1292safely_chroot(const char *path, uid_t uid)
1293{
1294 const char *cp;
1295 char component[MAXPATHLEN];
1296 struct stat st;
1297
1298 if (*path != '/')
1299 fatal("chroot path does not begin at root");
1300 if (strlen(path) >= sizeof(component))
1301 fatal("chroot path too long");
1302
1303 /*
1304 * Descend the path, checking that each component is a
1305 * root-owned directory with strict permissions.
1306 */
1307 for (cp = path; cp != NULL;) {
1308 if ((cp = strchr(cp, '/')) == NULL)
1309 strlcpy(component, path, sizeof(component));
1310 else {
1311 cp++;
1312 memcpy(component, path, cp - path);
1313 component[cp - path] = '\0';
1314 }
1315
1316 debug3("%s: checking '%s'", __func__, component);
1317
1318 if (stat(component, &st) != 0)
1319 fatal("%s: stat(\"%s\"): %s", __func__,
1320 component, strerror(errno));
1321 if (st.st_uid != 0 || (st.st_mode & 022) != 0)
1322 fatal("bad ownership or modes for chroot "
1323 "directory %s\"%s\"",
1324 cp == NULL ? "" : "component ", component);
1325 if (!S_ISDIR(st.st_mode))
1326 fatal("chroot path %s\"%s\" is not a directory",
1327 cp == NULL ? "" : "component ", component);
1328
1329 }
1330
1331 if (chdir(path) == -1)
1332 fatal("Unable to chdir to chroot path \"%s\": "
1333 "%s", path, strerror(errno));
1334 if (chroot(path) == -1)
1335 fatal("chroot(\"%s\"): %s", path, strerror(errno));
1336 if (chdir("/") == -1)
1337 fatal("%s: chdir(/) after chroot: %s",
1338 __func__, strerror(errno));
1339 verbose("Changed root directory to \"%s\"", path);
1340}
1341
1342/* Set login name, uid, gid, and groups. */
1343void
1344do_setusercontext(struct passwd *pw)
1345{
1346 char *chroot_path, *tmp;
1347
1348#ifndef HAVE_CYGWIN
1349 if (getuid() == 0 || geteuid() == 0)
1350#endif /* HAVE_CYGWIN */
1351 {
1352
1353#ifdef HAVE_SETPCRED
1354 if (setpcred(pw->pw_name, (char **)NULL) == -1)
1355 fatal("Failed to set process credentials");
1356#endif /* HAVE_SETPCRED */
1357#ifdef HAVE_LOGIN_CAP
1358# ifdef __bsdi__
1359 setpgid(0, 0);
1360# endif
1361# ifdef USE_PAM
1362 if (options.use_pam) {
1363 do_pam_setcred(use_privsep);
1364 }
1365# endif /* USE_PAM */
1366 if (setusercontext(lc, pw, pw->pw_uid,
1367 (LOGIN_SETALL & ~(LOGIN_SETPATH|LOGIN_SETUSER))) < 0) {
1368 perror("unable to set user context");
1369 exit(1);
1370 }
1371#else
1372# if defined(HAVE_GETLUID) && defined(HAVE_SETLUID)
1373 /* Sets login uid for accounting */
1374 if (getluid() == -1 && setluid(pw->pw_uid) == -1)
1375 error("setluid: %s", strerror(errno));
1376# endif /* defined(HAVE_GETLUID) && defined(HAVE_SETLUID) */
1377
1378 if (setlogin(pw->pw_name) < 0)
1379 error("setlogin failed: %s", strerror(errno));
1380 if (setgid(pw->pw_gid) < 0) {
1381 perror("setgid");
1382 exit(1);
1383 }
1384 /* Initialize the group list. */
1385 if (initgroups(pw->pw_name, pw->pw_gid) < 0) {
1386 perror("initgroups");
1387 exit(1);
1388 }
1389 endgrent();
1390# ifdef USE_PAM
1391 /*
1392 * PAM credentials may take the form of supplementary groups.
1393 * These will have been wiped by the above initgroups() call.
1394 * Reestablish them here.
1395 */
1396 if (options.use_pam) {
1397 do_pam_setcred(use_privsep);
1398 }
1399# endif /* USE_PAM */
1400# if defined(WITH_IRIX_PROJECT) || defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY)
1401 irix_setusercontext(pw);
1402# endif /* defined(WITH_IRIX_PROJECT) || defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY) */
1403# ifdef _AIX
1404 aix_usrinfo(pw);
1405# endif /* _AIX */
1406# ifdef USE_LIBIAF
1407 if (set_id(pw->pw_name) != 0) {
1408 exit(1);
1409 }
1410# endif /* USE_LIBIAF */
1411#endif
1412
1413 if (options.chroot_directory != NULL &&
1414 strcasecmp(options.chroot_directory, "none") != 0) {
1415 tmp = tilde_expand_filename(options.chroot_directory,
1416 pw->pw_uid);
1417 chroot_path = percent_expand(tmp, "h", pw->pw_dir,
1418 "u", pw->pw_name, (char *)NULL);
1419 safely_chroot(chroot_path, pw->pw_uid);
1420 free(tmp);
1421 free(chroot_path);
1422 }
1423
1424#ifdef HAVE_LOGIN_CAP
1425 if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUSER) < 0) {
1426 perror("unable to set user context (setuser)");
1427 exit(1);
1428 }
1429#else
1430 /* Permanently switch to the desired uid. */
1431 permanently_set_uid(pw);
1432#endif
1433 }
1434
1435#ifdef HAVE_CYGWIN
1436 if (is_winnt)
1437#endif
1438 if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
1439 fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
1440
1441#ifdef WITH_SELINUX
1442 ssh_selinux_setup_exec_context(pw->pw_name);
1443#endif
1444}
1445
1446static void
1447do_pwchange(Session *s)
1448{
1449 fflush(NULL);
1450 fprintf(stderr, "WARNING: Your password has expired.\n");
1451 if (s->ttyfd != -1) {
1452 fprintf(stderr,
1453 "You must change your password now and login again!\n");
1454#ifdef PASSWD_NEEDS_USERNAME
1455 execl(_PATH_PASSWD_PROG, "passwd", s->pw->pw_name,
1456 (char *)NULL);
1457#else
1458 execl(_PATH_PASSWD_PROG, "passwd", (char *)NULL);
1459#endif
1460 perror("passwd");
1461 } else {
1462 fprintf(stderr,
1463 "Password change required but no TTY available.\n");
1464 }
1465 exit(1);
1466}
1467
1468static void
1469launch_login(struct passwd *pw, const char *hostname)
1470{
1471 /* Launch login(1). */
1472
1473 execl(LOGIN_PROGRAM, "login", "-h", hostname,
1474#ifdef xxxLOGIN_NEEDS_TERM
1475 (s->term ? s->term : "unknown"),
1476#endif /* LOGIN_NEEDS_TERM */
1477#ifdef LOGIN_NO_ENDOPT
1478 "-p", "-f", pw->pw_name, (char *)NULL);
1479#else
1480 "-p", "-f", "--", pw->pw_name, (char *)NULL);
1481#endif
1482
1483 /* Login couldn't be executed, die. */
1484
1485 perror("login");
1486 exit(1);
1487}
1488
1489static void
1490child_close_fds(void)
1491{
1492 int i;
1493
1494 if (packet_get_connection_in() == packet_get_connection_out())
1495 close(packet_get_connection_in());
1496 else {
1497 close(packet_get_connection_in());
1498 close(packet_get_connection_out());
1499 }
1500 /*
1501 * Close all descriptors related to channels. They will still remain
1502 * open in the parent.
1503 */
1504 /* XXX better use close-on-exec? -markus */
1505 channel_close_all();
1506
1507 /*
1508 * Close any extra file descriptors. Note that there may still be
1509 * descriptors left by system functions. They will be closed later.
1510 */
1511 endpwent();
1512
1513 /*
1514 * Close any extra open file descriptors so that we don't have them
1515 * hanging around in clients. Note that we want to do this after
1516 * initgroups, because at least on Solaris 2.3 it leaves file
1517 * descriptors open.
1518 */
1519 for (i = 3; i < 64; i++)
1520 close(i);
1521}
1522
1523/*
1524 * Performs common processing for the child, such as setting up the
1525 * environment, closing extra file descriptors, setting the user and group
1526 * ids, and executing the command or shell.
1527 */
1528#define ARGV_MAX 10
1529void
1530do_child(Session *s, const char *command)
1531{
1532 extern char **environ;
1533 char **env;
1534 char *argv[ARGV_MAX];
1535 const char *shell, *shell0, *hostname = NULL;
1536 struct passwd *pw = s->pw;
1537
1538 /* remove hostkey from the child's memory */
1539 destroy_sensitive_data();
1540
1541 /* Force a password change */
1542 if (s->authctxt->force_pwchange) {
1543 do_setusercontext(pw);
1544 child_close_fds();
1545 do_pwchange(s);
1546 exit(1);
1547 }
1548
1549 /* login(1) is only called if we execute the login shell */
1550 if (options.use_login && command != NULL)
1551 options.use_login = 0;
1552
1553#ifdef _UNICOS
1554 cray_setup(pw->pw_uid, pw->pw_name, command);
1555#endif /* _UNICOS */
1556
1557 /*
1558 * Login(1) does this as well, and it needs uid 0 for the "-h"
1559 * switch, so we let login(1) to this for us.
1560 */
1561 if (!options.use_login) {
1562#ifdef HAVE_OSF_SIA
1563 session_setup_sia(pw, s->ttyfd == -1 ? NULL : s->tty);
1564 if (!check_quietlogin(s, command))
1565 do_motd();
1566#else /* HAVE_OSF_SIA */
1567 /* When PAM is enabled we rely on it to do the nologin check */
1568 if (!options.use_pam)
1569 do_nologin(pw);
1570 do_setusercontext(pw);
1571 /*
1572 * PAM session modules in do_setusercontext may have
1573 * generated messages, so if this in an interactive
1574 * login then display them too.
1575 */
1576 if (!check_quietlogin(s, command))
1577 display_loginmsg();
1578#endif /* HAVE_OSF_SIA */
1579 }
1580
1581#ifdef USE_PAM
1582 if (options.use_pam && !options.use_login && !is_pam_session_open()) {
1583 debug3("PAM session not opened, exiting");
1584 display_loginmsg();
1585 exit(254);
1586 }
1587#endif
1588
1589 /*
1590 * Get the shell from the password data. An empty shell field is
1591 * legal, and means /bin/sh.
1592 */
1593 shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1594
1595 /*
1596 * Make sure $SHELL points to the shell from the password file,
1597 * even if shell is overridden from login.conf
1598 */
1599 env = do_setup_env(s, shell);
1600
1601#ifdef HAVE_LOGIN_CAP
1602 shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
1603#endif
1604
1605 /* we have to stash the hostname before we close our socket. */
1606 if (options.use_login)
1607 hostname = get_remote_name_or_ip(utmp_len,
1608 options.use_dns);
1609 /*
1610 * Close the connection descriptors; note that this is the child, and
1611 * the server will still have the socket open, and it is important
1612 * that we do not shutdown it. Note that the descriptors cannot be
1613 * closed before building the environment, as we call
1614 * get_remote_ipaddr there.
1615 */
1616 child_close_fds();
1617
1618 /*
1619 * Must take new environment into use so that .ssh/rc,
1620 * /etc/ssh/sshrc and xauth are run in the proper environment.
1621 */
1622 environ = env;
1623
1624#if defined(KRB5) && defined(USE_AFS)
1625 /*
1626 * At this point, we check to see if AFS is active and if we have
1627 * a valid Kerberos 5 TGT. If so, it seems like a good idea to see
1628 * if we can (and need to) extend the ticket into an AFS token. If
1629 * we don't do this, we run into potential problems if the user's
1630 * home directory is in AFS and it's not world-readable.
1631 */
1632
1633 if (options.kerberos_get_afs_token && k_hasafs() &&
1634 (s->authctxt->krb5_ctx != NULL)) {
1635 char cell[64];
1636
1637 debug("Getting AFS token");
1638
1639 k_setpag();
1640
1641 if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
1642 krb5_afslog(s->authctxt->krb5_ctx,
1643 s->authctxt->krb5_fwd_ccache, cell, NULL);
1644
1645 krb5_afslog_home(s->authctxt->krb5_ctx,
1646 s->authctxt->krb5_fwd_ccache, NULL, NULL, pw->pw_dir);
1647 }
1648#endif
1649
1650 /* Change current directory to the user's home directory. */
1651 if (chdir(pw->pw_dir) < 0) {
1652 fprintf(stderr, "Could not chdir to home directory %s: %s\n",
1653 pw->pw_dir, strerror(errno));
1654#ifdef HAVE_LOGIN_CAP
1655 if (login_getcapbool(lc, "requirehome", 0))
1656 exit(1);
1657#endif
1658 }
1659
1660 closefrom(STDERR_FILENO + 1);
1661
1662 if (!options.use_login)
1663 do_rc_files(s, shell);
1664
1665 /* restore SIGPIPE for child */
1666 signal(SIGPIPE, SIG_DFL);
1667
1668 if (s->is_subsystem == SUBSYSTEM_INT_SFTP) {
1669 extern int optind, optreset;
1670 int i;
1671 char *p, *args;
1672
1673 setproctitle("%s@internal-sftp-server", s->pw->pw_name);
1674 args = strdup(command ? command : "sftp-server");
1675 for (i = 0, (p = strtok(args, " ")); p; (p = strtok(NULL, " ")))
1676 if (i < ARGV_MAX - 1)
1677 argv[i++] = p;
1678 argv[i] = NULL;
1679 optind = optreset = 1;
1680 __progname = argv[0];
1681 exit(sftp_server_main(i, argv, s->pw));
1682 }
1683
1684 if (options.use_login) {
1685 launch_login(pw, hostname);
1686 /* NEVERREACHED */
1687 }
1688
1689 /* Get the last component of the shell name. */
1690 if ((shell0 = strrchr(shell, '/')) != NULL)
1691 shell0++;
1692 else
1693 shell0 = shell;
1694
1695 /*
1696 * If we have no command, execute the shell. In this case, the shell
1697 * name to be passed in argv[0] is preceded by '-' to indicate that
1698 * this is a login shell.
1699 */
1700 if (!command) {
1701 char argv0[256];
1702
1703 /* Start the shell. Set initial character to '-'. */
1704 argv0[0] = '-';
1705
1706 if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1)
1707 >= sizeof(argv0) - 1) {
1708 errno = EINVAL;
1709 perror(shell);
1710 exit(1);
1711 }
1712
1713 /* Execute the shell. */
1714 argv[0] = argv0;
1715 argv[1] = NULL;
1716 execve(shell, argv, env);
1717
1718 /* Executing the shell failed. */
1719 perror(shell);
1720 exit(1);
1721 }
1722 /*
1723 * Execute the command using the user's shell. This uses the -c
1724 * option to execute the command.
1725 */
1726 argv[0] = (char *) shell0;
1727 argv[1] = "-c";
1728 argv[2] = (char *) command;
1729 argv[3] = NULL;
1730 execve(shell, argv, env);
1731 perror(shell);
1732 exit(1);
1733}
1734
1735Session *
1736session_new(void)
1737{
1738 int i;
1739 static int did_init = 0;
1740 if (!did_init) {
1741 debug("session_new: init");
1742 for (i = 0; i < MAX_SESSIONS; i++) {
1743 sessions[i].used = 0;
1744 }
1745 did_init = 1;
1746 }
1747 for (i = 0; i < MAX_SESSIONS; i++) {
1748 Session *s = &sessions[i];
1749 if (! s->used) {
1750 memset(s, 0, sizeof(*s));
1751 s->chanid = -1;
1752 s->ptyfd = -1;
1753 s->ttyfd = -1;
1754 s->used = 1;
1755 s->self = i;
1756 s->x11_chanids = NULL;
1757 debug("session_new: session %d", i);
1758 return s;
1759 }
1760 }
1761 return NULL;
1762}
1763
1764static void
1765session_dump(void)
1766{
1767 int i;
1768 for (i = 0; i < MAX_SESSIONS; i++) {
1769 Session *s = &sessions[i];
1770 debug("dump: used %d session %d %p channel %d pid %ld",
1771 s->used,
1772 s->self,
1773 s,
1774 s->chanid,
1775 (long)s->pid);
1776 }
1777}
1778
1779int
1780session_open(Authctxt *authctxt, int chanid)
1781{
1782 Session *s = session_new();
1783 debug("session_open: channel %d", chanid);
1784 if (s == NULL) {
1785 error("no more sessions");
1786 return 0;
1787 }
1788 s->authctxt = authctxt;
1789 s->pw = authctxt->pw;
1790 if (s->pw == NULL || !authctxt->valid)
1791 fatal("no user for session %d", s->self);
1792 debug("session_open: session %d: link with channel %d", s->self, chanid);
1793 s->chanid = chanid;
1794 return 1;
1795}
1796
1797Session *
1798session_by_tty(char *tty)
1799{
1800 int i;
1801 for (i = 0; i < MAX_SESSIONS; i++) {
1802 Session *s = &sessions[i];
1803 if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) {
1804 debug("session_by_tty: session %d tty %s", i, tty);
1805 return s;
1806 }
1807 }
1808 debug("session_by_tty: unknown tty %.100s", tty);
1809 session_dump();
1810 return NULL;
1811}
1812
1813static Session *
1814session_by_channel(int id)
1815{
1816 int i;
1817 for (i = 0; i < MAX_SESSIONS; i++) {
1818 Session *s = &sessions[i];
1819 if (s->used && s->chanid == id) {
1820 debug("session_by_channel: session %d channel %d", i, id);
1821 return s;
1822 }
1823 }
1824 debug("session_by_channel: unknown channel %d", id);
1825 session_dump();
1826 return NULL;
1827}
1828
1829static Session *
1830session_by_x11_channel(int id)
1831{
1832 int i, j;
1833
1834 for (i = 0; i < MAX_SESSIONS; i++) {
1835 Session *s = &sessions[i];
1836
1837 if (s->x11_chanids == NULL || !s->used)
1838 continue;
1839 for (j = 0; s->x11_chanids[j] != -1; j++) {
1840 if (s->x11_chanids[j] == id) {
1841 debug("session_by_x11_channel: session %d "
1842 "channel %d", s->self, id);
1843 return s;
1844 }
1845 }
1846 }
1847 debug("session_by_x11_channel: unknown channel %d", id);
1848 session_dump();
1849 return NULL;
1850}
1851
1852static Session *
1853session_by_pid(pid_t pid)
1854{
1855 int i;
1856 debug("session_by_pid: pid %ld", (long)pid);
1857 for (i = 0; i < MAX_SESSIONS; i++) {
1858 Session *s = &sessions[i];
1859 if (s->used && s->pid == pid)
1860 return s;
1861 }
1862 error("session_by_pid: unknown pid %ld", (long)pid);
1863 session_dump();
1864 return NULL;
1865}
1866
1867static int
1868session_window_change_req(Session *s)
1869{
1870 s->col = packet_get_int();
1871 s->row = packet_get_int();
1872 s->xpixel = packet_get_int();
1873 s->ypixel = packet_get_int();
1874 packet_check_eom();
1875 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1876 return 1;
1877}
1878
1879static int
1880session_pty_req(Session *s)
1881{
1882 u_int len;
1883 int n_bytes;
1884
1885 if (no_pty_flag) {
1886 debug("Allocating a pty not permitted for this authentication.");
1887 return 0;
1888 }
1889 if (s->ttyfd != -1) {
1890 packet_disconnect("Protocol error: you already have a pty.");
1891 return 0;
1892 }
1893
1894 s->term = packet_get_string(&len);
1895
1896 if (compat20) {
1897 s->col = packet_get_int();
1898 s->row = packet_get_int();
1899 } else {
1900 s->row = packet_get_int();
1901 s->col = packet_get_int();
1902 }
1903 s->xpixel = packet_get_int();
1904 s->ypixel = packet_get_int();
1905
1906 if (strcmp(s->term, "") == 0) {
1907 xfree(s->term);
1908 s->term = NULL;
1909 }
1910
1911 /* Allocate a pty and open it. */
1912 debug("Allocating pty.");
1913 if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty)))) {
1914 if (s->term)
1915 xfree(s->term);
1916 s->term = NULL;
1917 s->ptyfd = -1;
1918 s->ttyfd = -1;
1919 error("session_pty_req: session %d alloc failed", s->self);
1920 return 0;
1921 }
1922 debug("session_pty_req: session %d alloc %s", s->self, s->tty);
1923
1924 /* for SSH1 the tty modes length is not given */
1925 if (!compat20)
1926 n_bytes = packet_remaining();
1927 tty_parse_modes(s->ttyfd, &n_bytes);
1928
1929 if (!use_privsep)
1930 pty_setowner(s->pw, s->tty);
1931
1932 /* Set window size from the packet. */
1933 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1934
1935 packet_check_eom();
1936 session_proctitle(s);
1937 return 1;
1938}
1939
1940static int
1941session_subsystem_req(Session *s)
1942{
1943 struct stat st;
1944 u_int len;
1945 int success = 0;
1946 char *prog, *cmd, *subsys = packet_get_string(&len);
1947 u_int i;
1948
1949 packet_check_eom();
1950 logit("subsystem request for %.100s", subsys);
1951
1952 for (i = 0; i < options.num_subsystems; i++) {
1953 if (strcmp(subsys, options.subsystem_name[i]) == 0) {
1954 prog = options.subsystem_command[i];
1955 cmd = options.subsystem_args[i];
1956 if (!strcmp(INTERNAL_SFTP_NAME, prog)) {
1957 s->is_subsystem = SUBSYSTEM_INT_SFTP;
1958 } else if (stat(prog, &st) < 0) {
1959 error("subsystem: cannot stat %s: %s", prog,
1960 strerror(errno));
1961 break;
1962 } else {
1963 s->is_subsystem = SUBSYSTEM_EXT;
1964 }
1965 debug("subsystem: exec() %s", cmd);
1966 do_exec(s, cmd);
1967 success = 1;
1968 break;
1969 }
1970 }
1971
1972 if (!success)
1973 logit("subsystem request for %.100s failed, subsystem not found",
1974 subsys);
1975
1976 xfree(subsys);
1977 return success;
1978}
1979
1980static int
1981session_x11_req(Session *s)
1982{
1983 int success;
1984
1985 if (s->auth_proto != NULL || s->auth_data != NULL) {
1986 error("session_x11_req: session %d: "
1987 "x11 forwarding already active", s->self);
1988 return 0;
1989 }
1990 s->single_connection = packet_get_char();
1991 s->auth_proto = packet_get_string(NULL);
1992 s->auth_data = packet_get_string(NULL);
1993 s->screen = packet_get_int();
1994 packet_check_eom();
1995
1996 success = session_setup_x11fwd(s);
1997 if (!success) {
1998 xfree(s->auth_proto);
1999 xfree(s->auth_data);
2000 s->auth_proto = NULL;
2001 s->auth_data = NULL;
2002 }
2003 return success;
2004}
2005
2006static int
2007session_shell_req(Session *s)
2008{
2009 packet_check_eom();
2010 do_exec(s, NULL);
2011 return 1;
2012}
2013
2014static int
2015session_exec_req(Session *s)
2016{
2017 u_int len;
2018 char *command = packet_get_string(&len);
2019 packet_check_eom();
2020 do_exec(s, command);
2021 xfree(command);
2022 return 1;
2023}
2024
2025static int
2026session_break_req(Session *s)
2027{
2028
2029 packet_get_int(); /* ignored */
2030 packet_check_eom();
2031
2032 if (s->ttyfd == -1 ||
2033 tcsendbreak(s->ttyfd, 0) < 0)
2034 return 0;
2035 return 1;
2036}
2037
2038static int
2039session_env_req(Session *s)
2040{
2041 char *name, *val;
2042 u_int name_len, val_len, i;
2043
2044 name = packet_get_string(&name_len);
2045 val = packet_get_string(&val_len);
2046 packet_check_eom();
2047
2048 /* Don't set too many environment variables */
2049 if (s->num_env > 128) {
2050 debug2("Ignoring env request %s: too many env vars", name);
2051 goto fail;
2052 }
2053
2054 for (i = 0; i < options.num_accept_env; i++) {
2055 if (match_pattern(name, options.accept_env[i])) {
2056 debug2("Setting env %d: %s=%s", s->num_env, name, val);
2057 s->env = xrealloc(s->env, s->num_env + 1,
2058 sizeof(*s->env));
2059 s->env[s->num_env].name = name;
2060 s->env[s->num_env].val = val;
2061 s->num_env++;
2062 return (1);
2063 }
2064 }
2065 debug2("Ignoring env request %s: disallowed name", name);
2066
2067 fail:
2068 xfree(name);
2069 xfree(val);
2070 return (0);
2071}
2072
2073static int
2074session_auth_agent_req(Session *s)
2075{
2076 static int called = 0;
2077 packet_check_eom();
2078 if (no_agent_forwarding_flag) {
2079 debug("session_auth_agent_req: no_agent_forwarding_flag");
2080 return 0;
2081 }
2082 if (called) {
2083 return 0;
2084 } else {
2085 called = 1;
2086 return auth_input_request_forwarding(s->pw);
2087 }
2088}
2089
2090int
2091session_input_channel_req(Channel *c, const char *rtype)
2092{
2093 int success = 0;
2094 Session *s;
2095
2096 if ((s = session_by_channel(c->self)) == NULL) {
2097 logit("session_input_channel_req: no session %d req %.100s",
2098 c->self, rtype);
2099 return 0;
2100 }
2101 debug("session_input_channel_req: session %d req %s", s->self, rtype);
2102
2103 /*
2104 * a session is in LARVAL state until a shell, a command
2105 * or a subsystem is executed
2106 */
2107 if (c->type == SSH_CHANNEL_LARVAL) {
2108 if (strcmp(rtype, "shell") == 0) {
2109 success = session_shell_req(s);
2110 } else if (strcmp(rtype, "exec") == 0) {
2111 success = session_exec_req(s);
2112 } else if (strcmp(rtype, "pty-req") == 0) {
2113 success = session_pty_req(s);
2114 } else if (strcmp(rtype, "x11-req") == 0) {
2115 success = session_x11_req(s);
2116 } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
2117 success = session_auth_agent_req(s);
2118 } else if (strcmp(rtype, "subsystem") == 0) {
2119 success = session_subsystem_req(s);
2120 } else if (strcmp(rtype, "env") == 0) {
2121 success = session_env_req(s);
2122 }
2123 }
2124 if (strcmp(rtype, "window-change") == 0) {
2125 success = session_window_change_req(s);
2126 } else if (strcmp(rtype, "break") == 0) {
2127 success = session_break_req(s);
2128 }
2129
2130 return success;
2131}
2132
2133void
2134session_set_fds(Session *s, int fdin, int fdout, int fderr)
2135{
2136 if (!compat20)
2137 fatal("session_set_fds: called for proto != 2.0");
2138 /*
2139 * now that have a child and a pipe to the child,
2140 * we can activate our channel and register the fd's
2141 */
2142 if (s->chanid == -1)
2143 fatal("no channel for session %d", s->self);
2144 channel_set_fds(s->chanid,
2145 fdout, fdin, fderr,
2146 fderr == -1 ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
2147 1,
2148 CHAN_SES_WINDOW_DEFAULT);
2149}
2150
2151/*
2152 * Function to perform pty cleanup. Also called if we get aborted abnormally
2153 * (e.g., due to a dropped connection).
2154 */
2155void
2156session_pty_cleanup2(Session *s)
2157{
2158 if (s == NULL) {
2159 error("session_pty_cleanup: no session");
2160 return;
2161 }
2162 if (s->ttyfd == -1)
2163 return;
2164
2165 debug("session_pty_cleanup: session %d release %s", s->self, s->tty);
2166
2167 /* Record that the user has logged out. */
2168 if (s->pid != 0)
2169 record_logout(s->pid, s->tty, s->pw->pw_name);
2170
2171 /* Release the pseudo-tty. */
2172 if (getuid() == 0)
2173 pty_release(s->tty);
2174
2175 /*
2176 * Close the server side of the socket pairs. We must do this after
2177 * the pty cleanup, so that another process doesn't get this pty
2178 * while we're still cleaning up.
2179 */
2180 if (close(s->ptymaster) < 0)
2181 error("close(s->ptymaster/%d): %s", s->ptymaster, strerror(errno));
2182
2183 /* unlink pty from session */
2184 s->ttyfd = -1;
2185}
2186
2187void
2188session_pty_cleanup(Session *s)
2189{
2190 PRIVSEP(session_pty_cleanup2(s));
2191}
2192
2193static char *
2194sig2name(int sig)
2195{
2196#define SSH_SIG(x) if (sig == SIG ## x) return #x
2197 SSH_SIG(ABRT);
2198 SSH_SIG(ALRM);
2199 SSH_SIG(FPE);
2200 SSH_SIG(HUP);
2201 SSH_SIG(ILL);
2202 SSH_SIG(INT);
2203 SSH_SIG(KILL);
2204 SSH_SIG(PIPE);
2205 SSH_SIG(QUIT);
2206 SSH_SIG(SEGV);
2207 SSH_SIG(TERM);
2208 SSH_SIG(USR1);
2209 SSH_SIG(USR2);
2210#undef SSH_SIG
2211 return "SIG@openssh.com";
2212}
2213
2214static void
2215session_close_x11(int id)
2216{
2217 Channel *c;
2218
2219 if ((c = channel_by_id(id)) == NULL) {
2220 debug("session_close_x11: x11 channel %d missing", id);
2221 } else {
2222 /* Detach X11 listener */
2223 debug("session_close_x11: detach x11 channel %d", id);
2224 channel_cancel_cleanup(id);
2225 if (c->ostate != CHAN_OUTPUT_CLOSED)
2226 chan_mark_dead(c);
2227 }
2228}
2229
2230static void
2231session_close_single_x11(int id, void *arg)
2232{
2233 Session *s;
2234 u_int i;
2235
2236 debug3("session_close_single_x11: channel %d", id);
2237 channel_cancel_cleanup(id);
2238 if ((s = session_by_x11_channel(id)) == NULL)
2239 fatal("session_close_single_x11: no x11 channel %d", id);
2240 for (i = 0; s->x11_chanids[i] != -1; i++) {
2241 debug("session_close_single_x11: session %d: "
2242 "closing channel %d", s->self, s->x11_chanids[i]);
2243 /*
2244 * The channel "id" is already closing, but make sure we
2245 * close all of its siblings.
2246 */
2247 if (s->x11_chanids[i] != id)
2248 session_close_x11(s->x11_chanids[i]);
2249 }
2250 xfree(s->x11_chanids);
2251 s->x11_chanids = NULL;
2252 if (s->display) {
2253 xfree(s->display);
2254 s->display = NULL;
2255 }
2256 if (s->auth_proto) {
2257 xfree(s->auth_proto);
2258 s->auth_proto = NULL;
2259 }
2260 if (s->auth_data) {
2261 xfree(s->auth_data);
2262 s->auth_data = NULL;
2263 }
2264 if (s->auth_display) {
2265 xfree(s->auth_display);
2266 s->auth_display = NULL;
2267 }
2268}
2269
2270static void
2271session_exit_message(Session *s, int status)
2272{
2273 Channel *c;
2274
2275 if ((c = channel_lookup(s->chanid)) == NULL)
2276 fatal("session_exit_message: session %d: no channel %d",
2277 s->self, s->chanid);
2278 debug("session_exit_message: session %d channel %d pid %ld",
2279 s->self, s->chanid, (long)s->pid);
2280
2281 if (WIFEXITED(status)) {
2282 channel_request_start(s->chanid, "exit-status", 0);
2283 packet_put_int(WEXITSTATUS(status));
2284 packet_send();
2285 } else if (WIFSIGNALED(status)) {
2286 channel_request_start(s->chanid, "exit-signal", 0);
2287 packet_put_cstring(sig2name(WTERMSIG(status)));
2288#ifdef WCOREDUMP
2289 packet_put_char(WCOREDUMP(status)? 1 : 0);
2290#else /* WCOREDUMP */
2291 packet_put_char(0);
2292#endif /* WCOREDUMP */
2293 packet_put_cstring("");
2294 packet_put_cstring("");
2295 packet_send();
2296 } else {
2297 /* Some weird exit cause. Just exit. */
2298 packet_disconnect("wait returned status %04x.", status);
2299 }
2300
2301 /* disconnect channel */
2302 debug("session_exit_message: release channel %d", s->chanid);
2303
2304 /*
2305 * Adjust cleanup callback attachment to send close messages when
2306 * the channel gets EOF. The session will be then be closed
2307 * by session_close_by_channel when the childs close their fds.
2308 */
2309 channel_register_cleanup(c->self, session_close_by_channel, 1);
2310
2311 /*
2312 * emulate a write failure with 'chan_write_failed', nobody will be
2313 * interested in data we write.
2314 * Note that we must not call 'chan_read_failed', since there could
2315 * be some more data waiting in the pipe.
2316 */
2317 if (c->ostate != CHAN_OUTPUT_CLOSED)
2318 chan_write_failed(c);
2319}
2320
2321void
2322session_close(Session *s)
2323{
2324 u_int i;
2325
2326 debug("session_close: session %d pid %ld", s->self, (long)s->pid);
2327 if (s->ttyfd != -1)
2328 session_pty_cleanup(s);
2329 if (s->term)
2330 xfree(s->term);
2331 if (s->display)
2332 xfree(s->display);
2333 if (s->x11_chanids)
2334 xfree(s->x11_chanids);
2335 if (s->auth_display)
2336 xfree(s->auth_display);
2337 if (s->auth_data)
2338 xfree(s->auth_data);
2339 if (s->auth_proto)
2340 xfree(s->auth_proto);
2341 s->used = 0;
2342 if (s->env != NULL) {
2343 for (i = 0; i < s->num_env; i++) {
2344 xfree(s->env[i].name);
2345 xfree(s->env[i].val);
2346 }
2347 xfree(s->env);
2348 }
2349 session_proctitle(s);
2350}
2351
2352void
2353session_close_by_pid(pid_t pid, int status)
2354{
2355 Session *s = session_by_pid(pid);
2356 if (s == NULL) {
2357 debug("session_close_by_pid: no session for pid %ld",
2358 (long)pid);
2359 return;
2360 }
2361 if (s->chanid != -1)
2362 session_exit_message(s, status);
2363 if (s->ttyfd != -1)
2364 session_pty_cleanup(s);
2365 s->pid = 0;
2366}
2367
2368/*
2369 * this is called when a channel dies before
2370 * the session 'child' itself dies
2371 */
2372void
2373session_close_by_channel(int id, void *arg)
2374{
2375 Session *s = session_by_channel(id);
2376 u_int i;
2377
2378 if (s == NULL) {
2379 debug("session_close_by_channel: no session for id %d", id);
2380 return;
2381 }
2382 debug("session_close_by_channel: channel %d child %ld",
2383 id, (long)s->pid);
2384 if (s->pid != 0) {
2385 debug("session_close_by_channel: channel %d: has child", id);
2386 /*
2387 * delay detach of session, but release pty, since
2388 * the fd's to the child are already closed
2389 */
2390 if (s->ttyfd != -1)
2391 session_pty_cleanup(s);
2392 return;
2393 }
2394 /* detach by removing callback */
2395 channel_cancel_cleanup(s->chanid);
2396
2397 /* Close any X11 listeners associated with this session */
2398 if (s->x11_chanids != NULL) {
2399 for (i = 0; s->x11_chanids[i] != -1; i++) {
2400 session_close_x11(s->x11_chanids[i]);
2401 s->x11_chanids[i] = -1;
2402 }
2403 }
2404
2405 s->chanid = -1;
2406 session_close(s);
2407}
2408
2409void
2410session_destroy_all(void (*closefunc)(Session *))
2411{
2412 int i;
2413 for (i = 0; i < MAX_SESSIONS; i++) {
2414 Session *s = &sessions[i];
2415 if (s->used) {
2416 if (closefunc != NULL)
2417 closefunc(s);
2418 else
2419 session_close(s);
2420 }
2421 }
2422}
2423
2424static char *
2425session_tty_list(void)
2426{
2427 static char buf[1024];
2428 int i;
2429 char *cp;
2430
2431 buf[0] = '\0';
2432 for (i = 0; i < MAX_SESSIONS; i++) {
2433 Session *s = &sessions[i];
2434 if (s->used && s->ttyfd != -1) {
2435
2436 if (strncmp(s->tty, "/dev/", 5) != 0) {
2437 cp = strrchr(s->tty, '/');
2438 cp = (cp == NULL) ? s->tty : cp + 1;
2439 } else
2440 cp = s->tty + 5;
2441
2442 if (buf[0] != '\0')
2443 strlcat(buf, ",", sizeof buf);
2444 strlcat(buf, cp, sizeof buf);
2445 }
2446 }
2447 if (buf[0] == '\0')
2448 strlcpy(buf, "notty", sizeof buf);
2449 return buf;
2450}
2451
2452void
2453session_proctitle(Session *s)
2454{
2455 if (s->pw == NULL)
2456 error("no user for session %d", s->self);
2457 else
2458 setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
2459}
2460
2461int
2462session_setup_x11fwd(Session *s)
2463{
2464 struct stat st;
2465 char display[512], auth_display[512];
2466 char hostname[MAXHOSTNAMELEN];
2467 u_int i;
2468
2469 if (no_x11_forwarding_flag) {
2470 packet_send_debug("X11 forwarding disabled in user configuration file.");
2471 return 0;
2472 }
2473 if (!options.x11_forwarding) {
2474 debug("X11 forwarding disabled in server configuration file.");
2475 return 0;
2476 }
2477 if (!options.xauth_location ||
2478 (stat(options.xauth_location, &st) == -1)) {
2479 packet_send_debug("No xauth program; cannot forward with spoofing.");
2480 return 0;
2481 }
2482 if (options.use_login) {
2483 packet_send_debug("X11 forwarding disabled; "
2484 "not compatible with UseLogin=yes.");
2485 return 0;
2486 }
2487 if (s->display != NULL) {
2488 debug("X11 display already set.");
2489 return 0;
2490 }
2491 if (x11_create_display_inet(options.x11_display_offset,
2492 options.x11_use_localhost, s->single_connection,
2493 &s->display_number, &s->x11_chanids) == -1) {
2494 debug("x11_create_display_inet failed.");
2495 return 0;
2496 }
2497 for (i = 0; s->x11_chanids[i] != -1; i++) {
2498 channel_register_cleanup(s->x11_chanids[i],
2499 session_close_single_x11, 0);
2500 }
2501
2502 /* Set up a suitable value for the DISPLAY variable. */
2503 if (gethostname(hostname, sizeof(hostname)) < 0)
2504 fatal("gethostname: %.100s", strerror(errno));
2505 /*
2506 * auth_display must be used as the displayname when the
2507 * authorization entry is added with xauth(1). This will be
2508 * different than the DISPLAY string for localhost displays.
2509 */
2510 if (options.x11_use_localhost) {
2511 snprintf(display, sizeof display, "localhost:%u.%u",
2512 s->display_number, s->screen);
2513 snprintf(auth_display, sizeof auth_display, "unix:%u.%u",
2514 s->display_number, s->screen);
2515 s->display = xstrdup(display);
2516 s->auth_display = xstrdup(auth_display);
2517 } else {
2518#ifdef IPADDR_IN_DISPLAY
2519 struct hostent *he;
2520 struct in_addr my_addr;
2521
2522 he = gethostbyname(hostname);
2523 if (he == NULL) {
2524 error("Can't get IP address for X11 DISPLAY.");
2525 packet_send_debug("Can't get IP address for X11 DISPLAY.");
2526 return 0;
2527 }
2528 memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr));
2529 snprintf(display, sizeof display, "%.50s:%u.%u", inet_ntoa(my_addr),
2530 s->display_number, s->screen);
2531#else
2532 snprintf(display, sizeof display, "%.400s:%u.%u", hostname,
2533 s->display_number, s->screen);
2534#endif
2535 s->display = xstrdup(display);
2536 s->auth_display = xstrdup(display);
2537 }
2538
2539 return 1;
2540}
2541
2542static void
2543do_authenticated2(Authctxt *authctxt)
2544{
2545 server_loop2(authctxt);
2546}
2547
2548void
2549do_cleanup(Authctxt *authctxt)
2550{
2551 static int called = 0;
2552
2553 debug("do_cleanup");
2554
2555 /* no cleanup if we're in the child for login shell */
2556 if (is_child)
2557 return;
2558
2559 /* avoid double cleanup */
2560 if (called)
2561 return;
2562 called = 1;
2563
2564 if (authctxt == NULL)
2565 return;
2566
2567#ifdef USE_PAM
2568 if (options.use_pam) {
2569 sshpam_cleanup();
2570 sshpam_thread_cleanup();
2571 }
2572#endif
2573
2574 if (!authctxt->authenticated)
2575 return;
2576
2577#ifdef KRB5
2578 if (options.kerberos_ticket_cleanup &&
2579 authctxt->krb5_ctx)
2580 krb5_cleanup_proc(authctxt);
2581#endif
2582
2583#ifdef GSSAPI
2584 if (compat20 && options.gss_cleanup_creds)
2585 ssh_gssapi_cleanup_creds();
2586#endif
2587
2588 /* remove agent socket */
2589 auth_sock_cleanup_proc(authctxt->pw);
2590
2591 /*
2592 * Cleanup ptys/utmp only if privsep is disabled,
2593 * or if running in monitor.
2594 */
2595 if (!use_privsep || mm_is_monitor())
2596 session_destroy_all(session_pty_cleanup2);
2597}
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