Add the DragonFly cvs id and perform general cleanups on cvs/rcs/sccs ids. Most
[dragonfly.git] / crypto / openssh / session.c
CommitLineData
984263bc
MD
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 1.150 2002/09/16 19:55:33 stevesk Exp $");
37RCSID("$FreeBSD: src/crypto/openssh/session.c,v 1.4.2.17 2003/02/03 17:31:07 des Exp $");
1de703da 38RCSID("$DragonFly: src/crypto/openssh/Attic/session.c,v 1.2 2003/06/17 04:24:36 dillon Exp $");
984263bc
MD
39
40#include "ssh.h"
41#include "ssh1.h"
42#include "ssh2.h"
43#include "xmalloc.h"
44#include "sshpty.h"
45#include "packet.h"
46#include "buffer.h"
47#include "mpaux.h"
48#include "uidswap.h"
49#include "compat.h"
50#include "channels.h"
51#include "bufaux.h"
52#include "auth.h"
53#include "auth-options.h"
54#include "pathnames.h"
55#include "log.h"
56#include "servconf.h"
57#include "sshlogin.h"
58#include "serverloop.h"
59#include "canohost.h"
60#include "session.h"
61#include "monitor_wrap.h"
62
63#ifdef HAVE_CYGWIN
64#include <windows.h>
65#include <sys/cygwin.h>
66#define is_winnt (GetVersion() < 0x80000000)
67#endif
68
69/* func */
70
71Session *session_new(void);
72void session_set_fds(Session *, int, int, int);
73void session_pty_cleanup(void *);
74void session_proctitle(Session *);
75int session_setup_x11fwd(Session *);
76void do_exec_pty(Session *, const char *);
77void do_exec_no_pty(Session *, const char *);
78void do_exec(Session *, const char *);
79void do_login(Session *, const char *);
80#ifdef LOGIN_NEEDS_UTMPX
81static void do_pre_login(Session *s);
82#endif
83void do_child(Session *, const char *);
84void do_motd(void);
85int check_quietlogin(Session *, const char *);
86
87static void do_authenticated1(Authctxt *);
88static void do_authenticated2(Authctxt *);
89
90static int session_pty_req(Session *);
91
92/* import */
93extern ServerOptions options;
94extern char *__progname;
95extern int log_stderr;
96extern int debug_flag;
97extern u_int utmp_len;
98extern int startup_pipe;
99extern void destroy_sensitive_data(void);
100
101/* original command from peer. */
102const char *original_command = NULL;
103
104/* data */
105#define MAX_SESSIONS 10
106Session sessions[MAX_SESSIONS];
107
108#ifdef WITH_AIXAUTHENTICATE
109char *aixloginmsg;
110#endif /* WITH_AIXAUTHENTICATE */
111
112#ifdef HAVE_LOGIN_CAP
113login_cap_t *lc;
114#endif
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(void *_pw)
124{
125 struct passwd *pw = _pw;
126
127 if (auth_sock_name != NULL) {
128 temporarily_use_uid(pw);
129 unlink(auth_sock_name);
130 rmdir(auth_sock_dir);
131 auth_sock_name = NULL;
132 restore_uid();
133 }
134}
135
136static int
137auth_input_request_forwarding(struct passwd * pw)
138{
139 Channel *nc;
140 int sock;
141 struct sockaddr_un sunaddr;
142
143 if (auth_sock_name != NULL) {
144 error("authentication forwarding requested twice.");
145 return 0;
146 }
147
148 /* Temporarily drop privileged uid for mkdir/bind. */
149 temporarily_use_uid(pw);
150
151 /* Allocate a buffer for the socket name, and format the name. */
152 auth_sock_name = xmalloc(MAXPATHLEN);
153 auth_sock_dir = xmalloc(MAXPATHLEN);
154 strlcpy(auth_sock_dir, "/tmp/ssh-XXXXXXXX", MAXPATHLEN);
155
156 /* Create private directory for socket */
157 if (mkdtemp(auth_sock_dir) == NULL) {
158 packet_send_debug("Agent forwarding disabled: "
159 "mkdtemp() failed: %.100s", strerror(errno));
160 restore_uid();
161 xfree(auth_sock_name);
162 xfree(auth_sock_dir);
163 auth_sock_name = NULL;
164 auth_sock_dir = NULL;
165 return 0;
166 }
167 snprintf(auth_sock_name, MAXPATHLEN, "%s/agent.%ld",
168 auth_sock_dir, (long) getpid());
169
170 /* delete agent socket on fatal() */
171 fatal_add_cleanup(auth_sock_cleanup_proc, pw);
172
173 /* Create the socket. */
174 sock = socket(AF_UNIX, SOCK_STREAM, 0);
175 if (sock < 0)
176 packet_disconnect("socket: %.100s", strerror(errno));
177
178 /* Bind it to the name. */
179 memset(&sunaddr, 0, sizeof(sunaddr));
180 sunaddr.sun_family = AF_UNIX;
181 strlcpy(sunaddr.sun_path, auth_sock_name, sizeof(sunaddr.sun_path));
182
183 if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0)
184 packet_disconnect("bind: %.100s", strerror(errno));
185
186 /* Restore the privileged uid. */
187 restore_uid();
188
189 /* Start listening on the socket. */
190 if (listen(sock, 5) < 0)
191 packet_disconnect("listen: %.100s", strerror(errno));
192
193 /* Allocate a channel for the authentication agent socket. */
194 nc = channel_new("auth socket",
195 SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1,
196 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
197 0, xstrdup("auth socket"), 1);
198 strlcpy(nc->path, auth_sock_name, sizeof(nc->path));
199 return 1;
200}
201
202
203void
204do_authenticated(Authctxt *authctxt)
205{
206 /*
207 * Cancel the alarm we set to limit the time taken for
208 * authentication.
209 */
210 alarm(0);
211 if (startup_pipe != -1) {
212 close(startup_pipe);
213 startup_pipe = -1;
214 }
215
216 /* setup the channel layer */
217 if (!no_port_forwarding_flag && options.allow_tcp_forwarding)
218 channel_permit_all_opens();
219
220 if (compat20)
221 do_authenticated2(authctxt);
222 else
223 do_authenticated1(authctxt);
224
225 /* remove agent socket */
226 if (auth_sock_name != NULL)
227 auth_sock_cleanup_proc(authctxt->pw);
228#ifdef KRB4
229 if (options.kerberos_ticket_cleanup)
230 krb4_cleanup_proc(authctxt);
231#endif
232#ifdef KRB5
233 if (options.kerberos_ticket_cleanup)
234 krb5_cleanup_proc(authctxt);
235#endif
236}
237
238/*
239 * Prepares for an interactive session. This is called after the user has
240 * been successfully authenticated. During this message exchange, pseudo
241 * terminals are allocated, X11, TCP/IP, and authentication agent forwardings
242 * are requested, etc.
243 */
244static void
245do_authenticated1(Authctxt *authctxt)
246{
247 Session *s;
248 char *command;
249 int success, type, screen_flag;
250 int enable_compression_after_reply = 0;
251 u_int proto_len, data_len, dlen, compression_level = 0;
252
253 s = session_new();
254 s->authctxt = authctxt;
255 s->pw = authctxt->pw;
256
257 /*
258 * We stay in this loop until the client requests to execute a shell
259 * or a command.
260 */
261 for (;;) {
262 success = 0;
263
264 /* Get a packet from the client. */
265 type = packet_read();
266
267 /* Process the packet. */
268 switch (type) {
269 case SSH_CMSG_REQUEST_COMPRESSION:
270 compression_level = packet_get_int();
271 packet_check_eom();
272 if (compression_level < 1 || compression_level > 9) {
273 packet_send_debug("Received illegal compression level %d.",
274 compression_level);
275 break;
276 }
277 if (!options.compression) {
278 debug2("compression disabled");
279 break;
280 }
281 /* Enable compression after we have responded with SUCCESS. */
282 enable_compression_after_reply = 1;
283 success = 1;
284 break;
285
286 case SSH_CMSG_REQUEST_PTY:
287 success = session_pty_req(s);
288 break;
289
290 case SSH_CMSG_X11_REQUEST_FORWARDING:
291 s->auth_proto = packet_get_string(&proto_len);
292 s->auth_data = packet_get_string(&data_len);
293
294 screen_flag = packet_get_protocol_flags() &
295 SSH_PROTOFLAG_SCREEN_NUMBER;
296 debug2("SSH_PROTOFLAG_SCREEN_NUMBER: %d", screen_flag);
297
298 if (packet_remaining() == 4) {
299 if (!screen_flag)
300 debug2("Buggy client: "
301 "X11 screen flag missing");
302 s->screen = packet_get_int();
303 } else {
304 s->screen = 0;
305 }
306 packet_check_eom();
307 success = session_setup_x11fwd(s);
308 if (!success) {
309 xfree(s->auth_proto);
310 xfree(s->auth_data);
311 s->auth_proto = NULL;
312 s->auth_data = NULL;
313 }
314 break;
315
316 case SSH_CMSG_AGENT_REQUEST_FORWARDING:
317 if (no_agent_forwarding_flag || compat13) {
318 debug("Authentication agent forwarding not permitted for this authentication.");
319 break;
320 }
321 debug("Received authentication agent forwarding request.");
322 success = auth_input_request_forwarding(s->pw);
323 break;
324
325 case SSH_CMSG_PORT_FORWARD_REQUEST:
326 if (no_port_forwarding_flag) {
327 debug("Port forwarding not permitted for this authentication.");
328 break;
329 }
330 if (!options.allow_tcp_forwarding) {
331 debug("Port forwarding not permitted.");
332 break;
333 }
334 debug("Received TCP/IP port forwarding request.");
335 channel_input_port_forward_request(s->pw->pw_uid == 0, options.gateway_ports);
336 success = 1;
337 break;
338
339 case SSH_CMSG_MAX_PACKET_SIZE:
340 if (packet_set_maxsize(packet_get_int()) > 0)
341 success = 1;
342 break;
343
344#if defined(AFS) || defined(KRB5)
345 case SSH_CMSG_HAVE_KERBEROS_TGT:
346 if (!options.kerberos_tgt_passing) {
347 verbose("Kerberos TGT passing disabled.");
348 } else {
349 char *kdata = packet_get_string(&dlen);
350 packet_check_eom();
351
352 /* XXX - 0x41, see creds_to_radix version */
353 if (kdata[0] != 0x41) {
354#ifdef KRB5
355 krb5_data tgt;
356 tgt.data = kdata;
357 tgt.length = dlen;
358
359 if (auth_krb5_tgt(s->authctxt, &tgt))
360 success = 1;
361 else
362 verbose("Kerberos v5 TGT refused for %.100s", s->authctxt->user);
363#endif /* KRB5 */
364 } else {
365#ifdef AFS
366 if (auth_krb4_tgt(s->authctxt, kdata))
367 success = 1;
368 else
369 verbose("Kerberos v4 TGT refused for %.100s", s->authctxt->user);
370#endif /* AFS */
371 }
372 xfree(kdata);
373 }
374 break;
375#endif /* AFS || KRB5 */
376
377#ifdef AFS
378 case SSH_CMSG_HAVE_AFS_TOKEN:
379 if (!options.afs_token_passing || !k_hasafs()) {
380 verbose("AFS token passing disabled.");
381 } else {
382 /* Accept AFS token. */
383 char *token = packet_get_string(&dlen);
384 packet_check_eom();
385
386 if (auth_afs_token(s->authctxt, token))
387 success = 1;
388 else
389 verbose("AFS token refused for %.100s",
390 s->authctxt->user);
391 xfree(token);
392 }
393 break;
394#endif /* AFS */
395
396 case SSH_CMSG_EXEC_SHELL:
397 case SSH_CMSG_EXEC_CMD:
398 if (type == SSH_CMSG_EXEC_CMD) {
399 command = packet_get_string(&dlen);
400 debug("Exec command '%.500s'", command);
401 do_exec(s, command);
402 xfree(command);
403 } else {
404 do_exec(s, NULL);
405 }
406 packet_check_eom();
407 session_close(s);
408 return;
409
410 default:
411 /*
412 * Any unknown messages in this phase are ignored,
413 * and a failure message is returned.
414 */
415 log("Unknown packet type received after authentication: %d", type);
416 }
417 packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE);
418 packet_send();
419 packet_write_wait();
420
421 /* Enable compression now that we have replied if appropriate. */
422 if (enable_compression_after_reply) {
423 enable_compression_after_reply = 0;
424 packet_start_compression(compression_level);
425 }
426 }
427}
428
429/*
430 * This is called to fork and execute a command when we have no tty. This
431 * will call do_child from the child, and server_loop from the parent after
432 * setting up file descriptors and such.
433 */
434void
435do_exec_no_pty(Session *s, const char *command)
436{
437 pid_t pid;
438
439#ifdef USE_PIPES
440 int pin[2], pout[2], perr[2];
441 /* Allocate pipes for communicating with the program. */
442 if (pipe(pin) < 0 || pipe(pout) < 0 || pipe(perr) < 0)
443 packet_disconnect("Could not create pipes: %.100s",
444 strerror(errno));
445#else /* USE_PIPES */
446 int inout[2], err[2];
447 /* Uses socket pairs to communicate with the program. */
448 if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0 ||
449 socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0)
450 packet_disconnect("Could not create socket pairs: %.100s",
451 strerror(errno));
452#endif /* USE_PIPES */
453 if (s == NULL)
454 fatal("do_exec_no_pty: no session");
455
456 session_proctitle(s);
457
458#if defined(USE_PAM)
459 do_pam_session(s->pw->pw_name, NULL);
460 do_pam_setcred(1);
461 if (is_pam_password_change_required())
462 packet_disconnect("Password change required but no "
463 "TTY available");
464#endif /* USE_PAM */
465
466 /* Fork the child. */
467 if ((pid = fork()) == 0) {
468 fatal_remove_all_cleanups();
469
470 /* Child. Reinitialize the log since the pid has changed. */
471 log_init(__progname, options.log_level, options.log_facility, log_stderr);
472
473 /*
474 * Create a new session and process group since the 4.4BSD
475 * setlogin() affects the entire process group.
476 */
477 if (setsid() < 0)
478 error("setsid failed: %.100s", strerror(errno));
479
480#ifdef USE_PIPES
481 /*
482 * Redirect stdin. We close the parent side of the socket
483 * pair, and make the child side the standard input.
484 */
485 close(pin[1]);
486 if (dup2(pin[0], 0) < 0)
487 perror("dup2 stdin");
488 close(pin[0]);
489
490 /* Redirect stdout. */
491 close(pout[0]);
492 if (dup2(pout[1], 1) < 0)
493 perror("dup2 stdout");
494 close(pout[1]);
495
496 /* Redirect stderr. */
497 close(perr[0]);
498 if (dup2(perr[1], 2) < 0)
499 perror("dup2 stderr");
500 close(perr[1]);
501#else /* USE_PIPES */
502 /*
503 * Redirect stdin, stdout, and stderr. Stdin and stdout will
504 * use the same socket, as some programs (particularly rdist)
505 * seem to depend on it.
506 */
507 close(inout[1]);
508 close(err[1]);
509 if (dup2(inout[0], 0) < 0) /* stdin */
510 perror("dup2 stdin");
511 if (dup2(inout[0], 1) < 0) /* stdout. Note: same socket as stdin. */
512 perror("dup2 stdout");
513 if (dup2(err[0], 2) < 0) /* stderr */
514 perror("dup2 stderr");
515#endif /* USE_PIPES */
516
517#ifdef _UNICOS
518 cray_init_job(s->pw); /* set up cray jid and tmpdir */
519#endif
520
521 /* Do processing for the child (exec command etc). */
522 do_child(s, command);
523 /* NOTREACHED */
524 }
525#ifdef _UNICOS
526 signal(WJSIGNAL, cray_job_termination_handler);
527#endif /* _UNICOS */
528#ifdef HAVE_CYGWIN
529 if (is_winnt)
530 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
531#endif
532 if (pid < 0)
533 packet_disconnect("fork failed: %.100s", strerror(errno));
534 s->pid = pid;
535 /* Set interactive/non-interactive mode. */
536 packet_set_interactive(s->display != NULL);
537#ifdef USE_PIPES
538 /* We are the parent. Close the child sides of the pipes. */
539 close(pin[0]);
540 close(pout[1]);
541 close(perr[1]);
542
543 if (compat20) {
544 session_set_fds(s, pin[1], pout[0], s->is_subsystem ? -1 : perr[0]);
545 } else {
546 /* Enter the interactive session. */
547 server_loop(pid, pin[1], pout[0], perr[0]);
548 /* server_loop has closed pin[1], pout[0], and perr[0]. */
549 }
550#else /* USE_PIPES */
551 /* We are the parent. Close the child sides of the socket pairs. */
552 close(inout[0]);
553 close(err[0]);
554
555 /*
556 * Enter the interactive session. Note: server_loop must be able to
557 * handle the case that fdin and fdout are the same.
558 */
559 if (compat20) {
560 session_set_fds(s, inout[1], inout[1], s->is_subsystem ? -1 : err[1]);
561 } else {
562 server_loop(pid, inout[1], inout[1], err[1]);
563 /* server_loop has closed inout[1] and err[1]. */
564 }
565#endif /* USE_PIPES */
566}
567
568/*
569 * This is called to fork and execute a command when we have a tty. This
570 * will call do_child from the child, and server_loop from the parent after
571 * setting up file descriptors, controlling tty, updating wtmp, utmp,
572 * lastlog, and other such operations.
573 */
574void
575do_exec_pty(Session *s, const char *command)
576{
577 int fdout, ptyfd, ttyfd, ptymaster;
578 pid_t pid;
579
580 if (s == NULL)
581 fatal("do_exec_pty: no session");
582 ptyfd = s->ptyfd;
583 ttyfd = s->ttyfd;
584
585#if defined(USE_PAM)
586 do_pam_session(s->pw->pw_name, s->tty);
587 do_pam_setcred(1);
588#endif
589
590 /* Fork the child. */
591 if ((pid = fork()) == 0) {
592 fatal_remove_all_cleanups();
593
594 /* Child. Reinitialize the log because the pid has changed. */
595 log_init(__progname, options.log_level, options.log_facility, log_stderr);
596 /* Close the master side of the pseudo tty. */
597 close(ptyfd);
598
599 /* Make the pseudo tty our controlling tty. */
600 pty_make_controlling_tty(&ttyfd, s->tty);
601
602 /* Redirect stdin/stdout/stderr from the pseudo tty. */
603 if (dup2(ttyfd, 0) < 0)
604 error("dup2 stdin: %s", strerror(errno));
605 if (dup2(ttyfd, 1) < 0)
606 error("dup2 stdout: %s", strerror(errno));
607 if (dup2(ttyfd, 2) < 0)
608 error("dup2 stderr: %s", strerror(errno));
609
610 /* Close the extra descriptor for the pseudo tty. */
611 close(ttyfd);
612
613 /* record login, etc. similar to login(1) */
614#ifndef HAVE_OSF_SIA
615 if (!(options.use_login && command == NULL)) {
616#ifdef _UNICOS
617 cray_init_job(s->pw); /* set up cray jid and tmpdir */
618#endif /* _UNICOS */
619 do_login(s, command);
620 }
621# ifdef LOGIN_NEEDS_UTMPX
622 else
623 do_pre_login(s);
624# endif
625#endif
626
627 /* Do common processing for the child, such as execing the command. */
628 do_child(s, command);
629 /* NOTREACHED */
630 }
631#ifdef _UNICOS
632 signal(WJSIGNAL, cray_job_termination_handler);
633#endif /* _UNICOS */
634#ifdef HAVE_CYGWIN
635 if (is_winnt)
636 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
637#endif
638 if (pid < 0)
639 packet_disconnect("fork failed: %.100s", strerror(errno));
640 s->pid = pid;
641
642 /* Parent. Close the slave side of the pseudo tty. */
643 close(ttyfd);
644
645 /*
646 * Create another descriptor of the pty master side for use as the
647 * standard input. We could use the original descriptor, but this
648 * simplifies code in server_loop. The descriptor is bidirectional.
649 */
650 fdout = dup(ptyfd);
651 if (fdout < 0)
652 packet_disconnect("dup #1 failed: %.100s", strerror(errno));
653
654 /* we keep a reference to the pty master */
655 ptymaster = dup(ptyfd);
656 if (ptymaster < 0)
657 packet_disconnect("dup #2 failed: %.100s", strerror(errno));
658 s->ptymaster = ptymaster;
659
660 /* Enter interactive session. */
661 packet_set_interactive(1);
662 if (compat20) {
663 session_set_fds(s, ptyfd, fdout, -1);
664 } else {
665 server_loop(pid, ptyfd, fdout, -1);
666 /* server_loop _has_ closed ptyfd and fdout. */
667 }
668}
669
670#ifdef LOGIN_NEEDS_UTMPX
671static void
672do_pre_login(Session *s)
673{
674 socklen_t fromlen;
675 struct sockaddr_storage from;
676 pid_t pid = getpid();
677
678 /*
679 * Get IP address of client. If the connection is not a socket, let
680 * the address be 0.0.0.0.
681 */
682 memset(&from, 0, sizeof(from));
683 fromlen = sizeof(from);
684 if (packet_connection_is_on_socket()) {
685 if (getpeername(packet_get_connection_in(),
686 (struct sockaddr *) & from, &fromlen) < 0) {
687 debug("getpeername: %.100s", strerror(errno));
688 fatal_cleanup();
689 }
690 }
691
692 record_utmp_only(pid, s->tty, s->pw->pw_name,
693 get_remote_name_or_ip(utmp_len, options.verify_reverse_mapping),
694 (struct sockaddr *)&from, fromlen);
695}
696#endif
697
698/*
699 * This is called to fork and execute a command. If another command is
700 * to be forced, execute that instead.
701 */
702void
703do_exec(Session *s, const char *command)
704{
705 if (forced_command) {
706 original_command = command;
707 command = forced_command;
708 debug("Forced command '%.900s'", command);
709 }
710
711 if (s->ttyfd != -1)
712 do_exec_pty(s, command);
713 else
714 do_exec_no_pty(s, command);
715
716 original_command = NULL;
717}
718
719
720/* administrative, login(1)-like work */
721void
722do_login(Session *s, const char *command)
723{
724 char *time_string;
725 socklen_t fromlen;
726 struct sockaddr_storage from;
727 struct passwd * pw = s->pw;
728 pid_t pid = getpid();
729
730 /*
731 * Get IP address of client. If the connection is not a socket, let
732 * the address be 0.0.0.0.
733 */
734 memset(&from, 0, sizeof(from));
735 fromlen = sizeof(from);
736 if (packet_connection_is_on_socket()) {
737 if (getpeername(packet_get_connection_in(),
738 (struct sockaddr *) & from, &fromlen) < 0) {
739 debug("getpeername: %.100s", strerror(errno));
740 fatal_cleanup();
741 }
742 }
743
744 /* Record that there was a login on that tty from the remote host. */
745 if (!use_privsep)
746 record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
747 get_remote_name_or_ip(utmp_len,
748 options.verify_reverse_mapping),
749 (struct sockaddr *)&from, fromlen);
750
751#ifdef USE_PAM
752 /*
753 * If password change is needed, do it now.
754 * This needs to occur before the ~/.hushlogin check.
755 */
756 if (is_pam_password_change_required()) {
757 print_pam_messages();
758 do_pam_chauthtok();
759 }
760#endif
761
762 if (check_quietlogin(s, command))
763 return;
764
765#ifdef USE_PAM
766 if (!is_pam_password_change_required())
767 print_pam_messages();
768#endif /* USE_PAM */
769#ifdef WITH_AIXAUTHENTICATE
770 if (aixloginmsg && *aixloginmsg)
771 printf("%s\n", aixloginmsg);
772#endif /* WITH_AIXAUTHENTICATE */
773
774#ifndef NO_SSH_LASTLOG
775 if (options.print_lastlog && s->last_login_time != 0) {
776 time_string = ctime(&s->last_login_time);
777 if (strchr(time_string, '\n'))
778 *strchr(time_string, '\n') = 0;
779 if (strcmp(s->hostname, "") == 0)
780 printf("Last login: %s\r\n", time_string);
781 else
782 printf("Last login: %s from %s\r\n", time_string,
783 s->hostname);
784 }
785#endif /* NO_SSH_LASTLOG */
786
787 do_motd();
788}
789
790/*
791 * Display the message of the day.
792 */
793void
794do_motd(void)
795{
796 FILE *f;
797 char buf[256];
798#ifdef HAVE_LOGIN_CAP
799 const char *fname;
800#endif
801
802#ifdef HAVE_LOGIN_CAP
803 fname = login_getcapstr(lc, "copyright", NULL, NULL);
804 if (fname != NULL && (f = fopen(fname, "r")) != NULL) {
805 while (fgets(buf, sizeof(buf), f) != NULL)
806 fputs(buf, stdout);
807 fclose(f);
808 } else
809#endif /* HAVE_LOGIN_CAP */
810 (void)printf("%s\n\t%s %s\n",
811 "Copyright (c) 1980, 1983, 1986, 1988, 1990, 1991, 1993, 1994",
812 "The Regents of the University of California. ",
813 "All rights reserved.");
814
815 (void)printf("\n");
816
817 if (options.print_motd) {
818#ifdef HAVE_LOGIN_CAP
819 f = fopen(login_getcapstr(lc, "welcome", "/etc/motd",
820 "/etc/motd"), "r");
821#else
822 f = fopen("/etc/motd", "r");
823#endif
824 if (f) {
825 while (fgets(buf, sizeof(buf), f))
826 fputs(buf, stdout);
827 fclose(f);
828 }
829 }
830}
831
832
833/*
834 * Check for quiet login, either .hushlogin or command given.
835 */
836int
837check_quietlogin(Session *s, const char *command)
838{
839 char buf[256];
840 struct passwd *pw = s->pw;
841 struct stat st;
842
843 /* Return 1 if .hushlogin exists or a command given. */
844 if (command != NULL)
845 return 1;
846 snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
847#ifdef HAVE_LOGIN_CAP
848 if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
849 return 1;
850#else
851 if (stat(buf, &st) >= 0)
852 return 1;
853#endif
854 return 0;
855}
856
857/*
858 * Sets the value of the given variable in the environment. If the variable
859 * already exists, its value is overriden.
860 */
861static void
862child_set_env(char ***envp, u_int *envsizep, const char *name,
863 const char *value)
864{
865 u_int i, namelen;
866 char **env;
867
868 /*
869 * Find the slot where the value should be stored. If the variable
870 * already exists, we reuse the slot; otherwise we append a new slot
871 * at the end of the array, expanding if necessary.
872 */
873 env = *envp;
874 namelen = strlen(name);
875 for (i = 0; env[i]; i++)
876 if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
877 break;
878 if (env[i]) {
879 /* Reuse the slot. */
880 xfree(env[i]);
881 } else {
882 /* New variable. Expand if necessary. */
883 if (i >= (*envsizep) - 1) {
884 if (*envsizep >= 1000)
885 fatal("child_set_env: too many env vars,"
886 " skipping: %.100s", name);
887 (*envsizep) += 50;
888 env = (*envp) = xrealloc(env, (*envsizep) * sizeof(char *));
889 }
890 /* Need to set the NULL pointer at end of array beyond the new slot. */
891 env[i + 1] = NULL;
892 }
893
894 /* Allocate space and format the variable in the appropriate slot. */
895 env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
896 snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
897}
898
899/*
900 * Reads environment variables from the given file and adds/overrides them
901 * into the environment. If the file does not exist, this does nothing.
902 * Otherwise, it must consist of empty lines, comments (line starts with '#')
903 * and assignments of the form name=value. No other forms are allowed.
904 */
905static void
906read_environment_file(char ***env, u_int *envsize,
907 const char *filename)
908{
909 FILE *f;
910 char buf[4096];
911 char *cp, *value;
912 u_int lineno = 0;
913
914 f = fopen(filename, "r");
915 if (!f)
916 return;
917
918 while (fgets(buf, sizeof(buf), f)) {
919 if (++lineno > 1000)
920 fatal("Too many lines in environment file %s", filename);
921 for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
922 ;
923 if (!*cp || *cp == '#' || *cp == '\n')
924 continue;
925 if (strchr(cp, '\n'))
926 *strchr(cp, '\n') = '\0';
927 value = strchr(cp, '=');
928 if (value == NULL) {
929 fprintf(stderr, "Bad line %u in %.100s\n", lineno,
930 filename);
931 continue;
932 }
933 /*
934 * Replace the equals sign by nul, and advance value to
935 * the value string.
936 */
937 *value = '\0';
938 value++;
939 child_set_env(env, envsize, cp, value);
940 }
941 fclose(f);
942}
943
944void copy_environment(char **source, char ***env, u_int *envsize)
945{
946 char *var_name, *var_val;
947 int i;
948
949 if (source == NULL)
950 return;
951
952 for(i = 0; source[i] != NULL; i++) {
953 var_name = xstrdup(source[i]);
954 if ((var_val = strstr(var_name, "=")) == NULL) {
955 xfree(var_name);
956 continue;
957 }
958 *var_val++ = '\0';
959
960 debug3("Copy environment: %s=%s", var_name, var_val);
961 child_set_env(env, envsize, var_name, var_val);
962
963 xfree(var_name);
964 }
965}
966
967static char **
968do_setup_env(Session *s, const char *shell)
969{
970 char buf[256];
971 u_int i, envsize;
972 char **env;
973#ifdef HAVE_LOGIN_CAP
974 extern char **environ;
975 char **senv, **var;
976#endif
977 struct passwd *pw = s->pw;
978
979 /* Initialize the environment. */
980 envsize = 100;
981 env = xmalloc(envsize * sizeof(char *));
982 env[0] = NULL;
983
984#ifdef HAVE_CYGWIN
985 /*
986 * The Windows environment contains some setting which are
987 * important for a running system. They must not be dropped.
988 */
989 copy_environment(environ, &env, &envsize);
990#endif
991
992 if (getenv("TZ"))
993 child_set_env(&env, &envsize, "TZ", getenv("TZ"));
994 if (!options.use_login) {
995 /* Set basic environment. */
996 child_set_env(&env, &envsize, "USER", pw->pw_name);
997 child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
998 child_set_env(&env, &envsize, "HOME", pw->pw_dir);
999 snprintf(buf, sizeof buf, "%.200s/%.50s",
1000 _PATH_MAILDIR, pw->pw_name);
1001 child_set_env(&env, &envsize, "MAIL", buf);
1002#ifdef HAVE_LOGIN_CAP
1003 child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
1004 child_set_env(&env, &envsize, "TERM", "su");
1005 senv = environ;
1006 environ = xmalloc(sizeof(char *));
1007 *environ = NULL;
1008 (void) setusercontext(lc, pw, pw->pw_uid,
1009 LOGIN_SETENV|LOGIN_SETPATH);
1010 copy_environment(environ, &env, &envsize);
1011 for (var = environ; *var != NULL; ++var)
1012 xfree(*var);
1013 xfree(environ);
1014 environ = senv;
1015#else /* HAVE_LOGIN_CAP */
1016# ifndef HAVE_CYGWIN
1017 /*
1018 * There's no standard path on Windows. The path contains
1019 * important components pointing to the system directories,
1020 * needed for loading shared libraries. So the path better
1021 * remains intact here.
1022 */
1023# ifdef SUPERUSER_PATH
1024 child_set_env(&env, &envsize, "PATH",
1025 s->pw->pw_uid == 0 ? SUPERUSER_PATH : _PATH_STDPATH);
1026# else
1027 child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
1028# endif /* SUPERUSER_PATH */
1029# endif /* HAVE_CYGWIN */
1030#endif /* HAVE_LOGIN_CAP */
1031
1032 /* Normal systems set SHELL by default. */
1033 child_set_env(&env, &envsize, "SHELL", shell);
1034 }
1035
1036 /* Set custom environment options from RSA authentication. */
1037 if (!options.use_login) {
1038 while (custom_environment) {
1039 struct envstring *ce = custom_environment;
1040 char *str = ce->s;
1041
1042 for (i = 0; str[i] != '=' && str[i]; i++)
1043 ;
1044 if (str[i] == '=') {
1045 str[i] = 0;
1046 child_set_env(&env, &envsize, str, str + i + 1);
1047 }
1048 custom_environment = ce->next;
1049 xfree(ce->s);
1050 xfree(ce);
1051 }
1052 }
1053
1054 /* SSH_CLIENT deprecated */
1055 snprintf(buf, sizeof buf, "%.50s %d %d",
1056 get_remote_ipaddr(), get_remote_port(), get_local_port());
1057 child_set_env(&env, &envsize, "SSH_CLIENT", buf);
1058
1059 snprintf(buf, sizeof buf, "%.50s %d %.50s %d",
1060 get_remote_ipaddr(), get_remote_port(),
1061 get_local_ipaddr(packet_get_connection_in()), get_local_port());
1062 child_set_env(&env, &envsize, "SSH_CONNECTION", buf);
1063
1064 if (s->ttyfd != -1)
1065 child_set_env(&env, &envsize, "SSH_TTY", s->tty);
1066 if (s->term)
1067 child_set_env(&env, &envsize, "TERM", s->term);
1068 if (s->display)
1069 child_set_env(&env, &envsize, "DISPLAY", s->display);
1070 if (original_command)
1071 child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
1072 original_command);
1073
1074#ifdef _UNICOS
1075 if (cray_tmpdir[0] != '\0')
1076 child_set_env(&env, &envsize, "TMPDIR", cray_tmpdir);
1077#endif /* _UNICOS */
1078
1079#ifdef _AIX
1080 {
1081 char *cp;
1082
1083 if ((cp = getenv("AUTHSTATE")) != NULL)
1084 child_set_env(&env, &envsize, "AUTHSTATE", cp);
1085 if ((cp = getenv("KRB5CCNAME")) != NULL)
1086 child_set_env(&env, &envsize, "KRB5CCNAME", cp);
1087 read_environment_file(&env, &envsize, "/etc/environment");
1088 }
1089#endif
1090#ifdef KRB4
1091 if (s->authctxt->krb4_ticket_file)
1092 child_set_env(&env, &envsize, "KRBTKFILE",
1093 s->authctxt->krb4_ticket_file);
1094#endif
1095#ifdef KRB5
1096 if (s->authctxt->krb5_ticket_file)
1097 child_set_env(&env, &envsize, "KRB5CCNAME",
1098 s->authctxt->krb5_ticket_file);
1099#endif
1100#ifdef USE_PAM
1101 /*
1102 * Pull in any environment variables that may have
1103 * been set by PAM.
1104 */
1105 {
1106 char **p;
1107
1108 p = fetch_pam_environment();
1109 copy_environment(p, &env, &envsize);
1110 free_pam_environment(p);
1111 }
1112#endif /* USE_PAM */
1113
1114 if (auth_sock_name != NULL)
1115 child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
1116 auth_sock_name);
1117
1118 /* read $HOME/.ssh/environment. */
1119 if (options.permit_user_env && !options.use_login) {
1120 snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
1121 strcmp(pw->pw_dir, "/") ? pw->pw_dir : "");
1122 read_environment_file(&env, &envsize, buf);
1123 }
1124 if (debug_flag) {
1125 /* dump the environment */
1126 fprintf(stderr, "Environment:\n");
1127 for (i = 0; env[i]; i++)
1128 fprintf(stderr, " %.200s\n", env[i]);
1129 }
1130 return env;
1131}
1132
1133/*
1134 * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found
1135 * first in this order).
1136 */
1137static void
1138do_rc_files(Session *s, const char *shell)
1139{
1140 FILE *f = NULL;
1141 char cmd[1024];
1142 int do_xauth;
1143 struct stat st;
1144
1145 do_xauth =
1146 s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
1147
1148 /* ignore _PATH_SSH_USER_RC for subsystems */
1149 if (!s->is_subsystem && (stat(_PATH_SSH_USER_RC, &st) >= 0)) {
1150 snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
1151 shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
1152 if (debug_flag)
1153 fprintf(stderr, "Running %s\n", cmd);
1154 f = popen(cmd, "w");
1155 if (f) {
1156 if (do_xauth)
1157 fprintf(f, "%s %s\n", s->auth_proto,
1158 s->auth_data);
1159 pclose(f);
1160 } else
1161 fprintf(stderr, "Could not run %s\n",
1162 _PATH_SSH_USER_RC);
1163 } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
1164 if (debug_flag)
1165 fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
1166 _PATH_SSH_SYSTEM_RC);
1167 f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
1168 if (f) {
1169 if (do_xauth)
1170 fprintf(f, "%s %s\n", s->auth_proto,
1171 s->auth_data);
1172 pclose(f);
1173 } else
1174 fprintf(stderr, "Could not run %s\n",
1175 _PATH_SSH_SYSTEM_RC);
1176 } else if (do_xauth && options.xauth_location != NULL) {
1177 /* Add authority data to .Xauthority if appropriate. */
1178 if (debug_flag) {
1179 fprintf(stderr,
1180 "Running %.500s add "
1181 "%.100s %.100s %.100s\n",
1182 options.xauth_location, s->auth_display,
1183 s->auth_proto, s->auth_data);
1184 }
1185 snprintf(cmd, sizeof cmd, "%s -q -",
1186 options.xauth_location);
1187 f = popen(cmd, "w");
1188 if (f) {
1189 fprintf(f, "add %s %s %s\n",
1190 s->auth_display, s->auth_proto,
1191 s->auth_data);
1192 pclose(f);
1193 } else {
1194 fprintf(stderr, "Could not run %s\n",
1195 cmd);
1196 }
1197 }
1198}
1199
1200static void
1201do_nologin(struct passwd *pw)
1202{
1203 FILE *f = NULL;
1204 char buf[1024];
1205
1206#ifdef HAVE_LOGIN_CAP
1207 if (!login_getcapbool(lc, "ignorenologin", 0) && pw->pw_uid)
1208 f = fopen(login_getcapstr(lc, "nologin", _PATH_NOLOGIN,
1209 _PATH_NOLOGIN), "r");
1210#else
1211 if (pw->pw_uid)
1212 f = fopen(_PATH_NOLOGIN, "r");
1213#endif
1214 if (f) {
1215 /* /etc/nologin exists. Print its contents and exit. */
1216 log("User %.100s not allowed because %s exists",
1217 pw->pw_name, _PATH_NOLOGIN);
1218 while (fgets(buf, sizeof(buf), f))
1219 fputs(buf, stderr);
1220 fclose(f);
1221 exit(254);
1222 }
1223}
1224
1225/* Set login name, uid, gid, and groups. */
1226void
1227do_setusercontext(struct passwd *pw)
1228{
1229#ifdef HAVE_CYGWIN
1230 if (is_winnt) {
1231#else /* HAVE_CYGWIN */
1232 if (getuid() == 0 || geteuid() == 0) {
1233#endif /* HAVE_CYGWIN */
1234#ifdef HAVE_SETPCRED
1235 setpcred(pw->pw_name);
1236#endif /* HAVE_SETPCRED */
1237#ifdef HAVE_LOGIN_CAP
1238# ifdef __bsdi__
1239 setpgid(0, 0);
1240# endif
1241 if (setusercontext(lc, pw, pw->pw_uid,
1242 (LOGIN_SETALL & ~(LOGIN_SETENV|LOGIN_SETPATH))) < 0) {
1243 perror("unable to set user context");
1244 exit(1);
1245 }
1246#else
1247# if defined(HAVE_GETLUID) && defined(HAVE_SETLUID)
1248 /* Sets login uid for accounting */
1249 if (getluid() == -1 && setluid(pw->pw_uid) == -1)
1250 error("setluid: %s", strerror(errno));
1251# endif /* defined(HAVE_GETLUID) && defined(HAVE_SETLUID) */
1252
1253 if (setlogin(pw->pw_name) < 0)
1254 error("setlogin failed: %s", strerror(errno));
1255 if (setgid(pw->pw_gid) < 0) {
1256 perror("setgid");
1257 exit(1);
1258 }
1259 /* Initialize the group list. */
1260 if (initgroups(pw->pw_name, pw->pw_gid) < 0) {
1261 perror("initgroups");
1262 exit(1);
1263 }
1264 endgrent();
1265# ifdef USE_PAM
1266 /*
1267 * PAM credentials may take the form of supplementary groups.
1268 * These will have been wiped by the above initgroups() call.
1269 * Reestablish them here.
1270 */
1271 do_pam_setcred(0);
1272# endif /* USE_PAM */
1273# if defined(WITH_IRIX_PROJECT) || defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY)
1274 irix_setusercontext(pw);
1275# endif /* defined(WITH_IRIX_PROJECT) || defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY) */
1276# ifdef _AIX
1277 aix_usrinfo(pw);
1278# endif /* _AIX */
1279 /* Permanently switch to the desired uid. */
1280 permanently_set_uid(pw);
1281#endif
1282 }
1283 if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
1284 fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
1285}
1286
1287static void
1288launch_login(struct passwd *pw, const char *hostname)
1289{
1290 /* Launch login(1). */
1291
1292 execl(LOGIN_PROGRAM, "login", "-h", hostname,
1293#ifdef xxxLOGIN_NEEDS_TERM
1294 (s->term ? s->term : "unknown"),
1295#endif /* LOGIN_NEEDS_TERM */
1296#ifdef LOGIN_NO_ENDOPT
1297 "-p", "-f", pw->pw_name, (char *)NULL);
1298#else
1299 "-p", "-f", "--", pw->pw_name, (char *)NULL);
1300#endif
1301
1302 /* Login couldn't be executed, die. */
1303
1304 perror("login");
1305 exit(1);
1306}
1307
1308/*
1309 * Performs common processing for the child, such as setting up the
1310 * environment, closing extra file descriptors, setting the user and group
1311 * ids, and executing the command or shell.
1312 */
1313void
1314do_child(Session *s, const char *command)
1315{
1316 extern char **environ;
1317 char **env;
1318 char *argv[10];
1319 const char *shell, *shell0, *hostname = NULL;
1320 struct passwd *pw = s->pw;
1321 u_int i;
1322#ifdef HAVE_LOGIN_CAP
1323 int lc_requirehome;
1324#endif
1325
1326 /* remove hostkey from the child's memory */
1327 destroy_sensitive_data();
1328
1329 /* login(1) is only called if we execute the login shell */
1330 if (options.use_login && command != NULL)
1331 options.use_login = 0;
1332
1333#ifdef _UNICOS
1334 cray_setup(pw->pw_uid, pw->pw_name, command);
1335#endif /* _UNICOS */
1336
1337 /*
1338 * Login(1) does this as well, and it needs uid 0 for the "-h"
1339 * switch, so we let login(1) to this for us.
1340 */
1341 if (!options.use_login) {
1342#ifdef HAVE_OSF_SIA
1343 session_setup_sia(pw->pw_name, s->ttyfd == -1 ? NULL : s->tty);
1344 if (!check_quietlogin(s, command))
1345 do_motd();
1346#else /* HAVE_OSF_SIA */
1347 do_nologin(pw);
1348 do_setusercontext(pw);
1349#endif /* HAVE_OSF_SIA */
1350 }
1351
1352 /*
1353 * Get the shell from the password data. An empty shell field is
1354 * legal, and means /bin/sh.
1355 */
1356 shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1357#ifdef HAVE_LOGIN_CAP
1358 shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
1359#endif
1360
1361 env = do_setup_env(s, shell);
1362
1363 /* we have to stash the hostname before we close our socket. */
1364 if (options.use_login)
1365 hostname = get_remote_name_or_ip(utmp_len,
1366 options.verify_reverse_mapping);
1367 /*
1368 * Close the connection descriptors; note that this is the child, and
1369 * the server will still have the socket open, and it is important
1370 * that we do not shutdown it. Note that the descriptors cannot be
1371 * closed before building the environment, as we call
1372 * get_remote_ipaddr there.
1373 */
1374 if (packet_get_connection_in() == packet_get_connection_out())
1375 close(packet_get_connection_in());
1376 else {
1377 close(packet_get_connection_in());
1378 close(packet_get_connection_out());
1379 }
1380 /*
1381 * Close all descriptors related to channels. They will still remain
1382 * open in the parent.
1383 */
1384 /* XXX better use close-on-exec? -markus */
1385 channel_close_all();
1386
1387#ifdef HAVE_LOGIN_CAP
1388 lc_requirehome = login_getcapbool(lc, "requirehome", 0);
1389 login_close(lc);
1390#endif
1391 /*
1392 * Close any extra file descriptors. Note that there may still be
1393 * descriptors left by system functions. They will be closed later.
1394 */
1395 endpwent();
1396
1397 /*
1398 * Close any extra open file descriptors so that we don\'t have them
1399 * hanging around in clients. Note that we want to do this after
1400 * initgroups, because at least on Solaris 2.3 it leaves file
1401 * descriptors open.
1402 */
1403 for (i = 3; i < 64; i++)
1404 close(i);
1405
1406 /*
1407 * Must take new environment into use so that .ssh/rc,
1408 * /etc/ssh/sshrc and xauth are run in the proper environment.
1409 */
1410 environ = env;
1411
1412#ifdef AFS
1413 /* Try to get AFS tokens for the local cell. */
1414 if (k_hasafs()) {
1415 char cell[64];
1416
1417 if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
1418 krb_afslog(cell, 0);
1419
1420 krb_afslog(0, 0);
1421 }
1422#endif /* AFS */
1423
1424 /* Change current directory to the user\'s home directory. */
1425 if (chdir(pw->pw_dir) < 0) {
1426 fprintf(stderr, "Could not chdir to home directory %s: %s\n",
1427 pw->pw_dir, strerror(errno));
1428#ifdef HAVE_LOGIN_CAP
1429 if (lc_requirehome)
1430 exit(1);
1431#endif
1432 }
1433
1434 if (!options.use_login)
1435 do_rc_files(s, shell);
1436
1437 /* restore SIGPIPE for child */
1438 signal(SIGPIPE, SIG_DFL);
1439
1440 if (options.use_login) {
1441 launch_login(pw, hostname);
1442 /* NEVERREACHED */
1443 }
1444
1445 /* Get the last component of the shell name. */
1446 if ((shell0 = strrchr(shell, '/')) != NULL)
1447 shell0++;
1448 else
1449 shell0 = shell;
1450
1451 /*
1452 * If we have no command, execute the shell. In this case, the shell
1453 * name to be passed in argv[0] is preceded by '-' to indicate that
1454 * this is a login shell.
1455 */
1456 if (!command) {
1457 char argv0[256];
1458
1459 /* Start the shell. Set initial character to '-'. */
1460 argv0[0] = '-';
1461
1462 if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1)
1463 >= sizeof(argv0) - 1) {
1464 errno = EINVAL;
1465 perror(shell);
1466 exit(1);
1467 }
1468
1469 /* Execute the shell. */
1470 argv[0] = argv0;
1471 argv[1] = NULL;
1472 execve(shell, argv, env);
1473
1474 /* Executing the shell failed. */
1475 perror(shell);
1476 exit(1);
1477 }
1478 /*
1479 * Execute the command using the user's shell. This uses the -c
1480 * option to execute the command.
1481 */
1482 argv[0] = (char *) shell0;
1483 argv[1] = "-c";
1484 argv[2] = (char *) command;
1485 argv[3] = NULL;
1486 execve(shell, argv, env);
1487 perror(shell);
1488 exit(1);
1489}
1490
1491Session *
1492session_new(void)
1493{
1494 int i;
1495 static int did_init = 0;
1496 if (!did_init) {
1497 debug("session_new: init");
1498 for (i = 0; i < MAX_SESSIONS; i++) {
1499 sessions[i].used = 0;
1500 }
1501 did_init = 1;
1502 }
1503 for (i = 0; i < MAX_SESSIONS; i++) {
1504 Session *s = &sessions[i];
1505 if (! s->used) {
1506 memset(s, 0, sizeof(*s));
1507 s->chanid = -1;
1508 s->ptyfd = -1;
1509 s->ttyfd = -1;
1510 s->used = 1;
1511 s->self = i;
1512 debug("session_new: session %d", i);
1513 return s;
1514 }
1515 }
1516 return NULL;
1517}
1518
1519static void
1520session_dump(void)
1521{
1522 int i;
1523 for (i = 0; i < MAX_SESSIONS; i++) {
1524 Session *s = &sessions[i];
1525 debug("dump: used %d session %d %p channel %d pid %ld",
1526 s->used,
1527 s->self,
1528 s,
1529 s->chanid,
1530 (long)s->pid);
1531 }
1532}
1533
1534int
1535session_open(Authctxt *authctxt, int chanid)
1536{
1537 Session *s = session_new();
1538 debug("session_open: channel %d", chanid);
1539 if (s == NULL) {
1540 error("no more sessions");
1541 return 0;
1542 }
1543 s->authctxt = authctxt;
1544 s->pw = authctxt->pw;
1545 if (s->pw == NULL)
1546 fatal("no user for session %d", s->self);
1547 debug("session_open: session %d: link with channel %d", s->self, chanid);
1548 s->chanid = chanid;
1549 return 1;
1550}
1551
1552Session *
1553session_by_tty(char *tty)
1554{
1555 int i;
1556 for (i = 0; i < MAX_SESSIONS; i++) {
1557 Session *s = &sessions[i];
1558 if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) {
1559 debug("session_by_tty: session %d tty %s", i, tty);
1560 return s;
1561 }
1562 }
1563 debug("session_by_tty: unknown tty %.100s", tty);
1564 session_dump();
1565 return NULL;
1566}
1567
1568static Session *
1569session_by_channel(int id)
1570{
1571 int i;
1572 for (i = 0; i < MAX_SESSIONS; i++) {
1573 Session *s = &sessions[i];
1574 if (s->used && s->chanid == id) {
1575 debug("session_by_channel: session %d channel %d", i, id);
1576 return s;
1577 }
1578 }
1579 debug("session_by_channel: unknown channel %d", id);
1580 session_dump();
1581 return NULL;
1582}
1583
1584static Session *
1585session_by_pid(pid_t pid)
1586{
1587 int i;
1588 debug("session_by_pid: pid %ld", (long)pid);
1589 for (i = 0; i < MAX_SESSIONS; i++) {
1590 Session *s = &sessions[i];
1591 if (s->used && s->pid == pid)
1592 return s;
1593 }
1594 error("session_by_pid: unknown pid %ld", (long)pid);
1595 session_dump();
1596 return NULL;
1597}
1598
1599static int
1600session_window_change_req(Session *s)
1601{
1602 s->col = packet_get_int();
1603 s->row = packet_get_int();
1604 s->xpixel = packet_get_int();
1605 s->ypixel = packet_get_int();
1606 packet_check_eom();
1607 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1608 return 1;
1609}
1610
1611static int
1612session_pty_req(Session *s)
1613{
1614 u_int len;
1615 int n_bytes;
1616
1617 if (no_pty_flag) {
1618 debug("Allocating a pty not permitted for this authentication.");
1619 return 0;
1620 }
1621 if (s->ttyfd != -1) {
1622 packet_disconnect("Protocol error: you already have a pty.");
1623 return 0;
1624 }
1625 /* Get the time and hostname when the user last logged in. */
1626 if (options.print_lastlog) {
1627 s->hostname[0] = '\0';
1628 s->last_login_time = get_last_login_time(s->pw->pw_uid,
1629 s->pw->pw_name, s->hostname, sizeof(s->hostname));
1630 }
1631
1632 s->term = packet_get_string(&len);
1633
1634 if (compat20) {
1635 s->col = packet_get_int();
1636 s->row = packet_get_int();
1637 } else {
1638 s->row = packet_get_int();
1639 s->col = packet_get_int();
1640 }
1641 s->xpixel = packet_get_int();
1642 s->ypixel = packet_get_int();
1643
1644 if (strcmp(s->term, "") == 0) {
1645 xfree(s->term);
1646 s->term = NULL;
1647 }
1648
1649 /* Allocate a pty and open it. */
1650 debug("Allocating pty.");
1651 if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty)))) {
1652 if (s->term)
1653 xfree(s->term);
1654 s->term = NULL;
1655 s->ptyfd = -1;
1656 s->ttyfd = -1;
1657 error("session_pty_req: session %d alloc failed", s->self);
1658 return 0;
1659 }
1660 debug("session_pty_req: session %d alloc %s", s->self, s->tty);
1661
1662 /* for SSH1 the tty modes length is not given */
1663 if (!compat20)
1664 n_bytes = packet_remaining();
1665 tty_parse_modes(s->ttyfd, &n_bytes);
1666
1667 /*
1668 * Add a cleanup function to clear the utmp entry and record logout
1669 * time in case we call fatal() (e.g., the connection gets closed).
1670 */
1671 fatal_add_cleanup(session_pty_cleanup, (void *)s);
1672 if (!use_privsep)
1673 pty_setowner(s->pw, s->tty);
1674
1675 /* Set window size from the packet. */
1676 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1677
1678 packet_check_eom();
1679 session_proctitle(s);
1680 return 1;
1681}
1682
1683static int
1684session_subsystem_req(Session *s)
1685{
1686 struct stat st;
1687 u_int len;
1688 int success = 0;
1689 char *cmd, *subsys = packet_get_string(&len);
1690 int i;
1691
1692 packet_check_eom();
1693 log("subsystem request for %.100s", subsys);
1694
1695 for (i = 0; i < options.num_subsystems; i++) {
1696 if (strcmp(subsys, options.subsystem_name[i]) == 0) {
1697 cmd = options.subsystem_command[i];
1698 if (stat(cmd, &st) < 0) {
1699 error("subsystem: cannot stat %s: %s", cmd,
1700 strerror(errno));
1701 break;
1702 }
1703 debug("subsystem: exec() %s", cmd);
1704 s->is_subsystem = 1;
1705 do_exec(s, cmd);
1706 success = 1;
1707 break;
1708 }
1709 }
1710
1711 if (!success)
1712 log("subsystem request for %.100s failed, subsystem not found",
1713 subsys);
1714
1715 xfree(subsys);
1716 return success;
1717}
1718
1719static int
1720session_x11_req(Session *s)
1721{
1722 int success;
1723
1724 s->single_connection = packet_get_char();
1725 s->auth_proto = packet_get_string(NULL);
1726 s->auth_data = packet_get_string(NULL);
1727 s->screen = packet_get_int();
1728 packet_check_eom();
1729
1730 success = session_setup_x11fwd(s);
1731 if (!success) {
1732 xfree(s->auth_proto);
1733 xfree(s->auth_data);
1734 s->auth_proto = NULL;
1735 s->auth_data = NULL;
1736 }
1737 return success;
1738}
1739
1740static int
1741session_shell_req(Session *s)
1742{
1743 packet_check_eom();
1744 do_exec(s, NULL);
1745 return 1;
1746}
1747
1748static int
1749session_exec_req(Session *s)
1750{
1751 u_int len;
1752 char *command = packet_get_string(&len);
1753 packet_check_eom();
1754 do_exec(s, command);
1755 xfree(command);
1756 return 1;
1757}
1758
1759static int
1760session_auth_agent_req(Session *s)
1761{
1762 static int called = 0;
1763 packet_check_eom();
1764 if (no_agent_forwarding_flag) {
1765 debug("session_auth_agent_req: no_agent_forwarding_flag");
1766 return 0;
1767 }
1768 if (called) {
1769 return 0;
1770 } else {
1771 called = 1;
1772 return auth_input_request_forwarding(s->pw);
1773 }
1774}
1775
1776int
1777session_input_channel_req(Channel *c, const char *rtype)
1778{
1779 int success = 0;
1780 Session *s;
1781
1782 if ((s = session_by_channel(c->self)) == NULL) {
1783 log("session_input_channel_req: no session %d req %.100s",
1784 c->self, rtype);
1785 return 0;
1786 }
1787 debug("session_input_channel_req: session %d req %s", s->self, rtype);
1788
1789 /*
1790 * a session is in LARVAL state until a shell, a command
1791 * or a subsystem is executed
1792 */
1793 if (c->type == SSH_CHANNEL_LARVAL) {
1794 if (strcmp(rtype, "shell") == 0) {
1795 success = session_shell_req(s);
1796 } else if (strcmp(rtype, "exec") == 0) {
1797 success = session_exec_req(s);
1798 } else if (strcmp(rtype, "pty-req") == 0) {
1799 success = session_pty_req(s);
1800 } else if (strcmp(rtype, "x11-req") == 0) {
1801 success = session_x11_req(s);
1802 } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
1803 success = session_auth_agent_req(s);
1804 } else if (strcmp(rtype, "subsystem") == 0) {
1805 success = session_subsystem_req(s);
1806 }
1807 }
1808 if (strcmp(rtype, "window-change") == 0) {
1809 success = session_window_change_req(s);
1810 }
1811 return success;
1812}
1813
1814void
1815session_set_fds(Session *s, int fdin, int fdout, int fderr)
1816{
1817 if (!compat20)
1818 fatal("session_set_fds: called for proto != 2.0");
1819 /*
1820 * now that have a child and a pipe to the child,
1821 * we can activate our channel and register the fd's
1822 */
1823 if (s->chanid == -1)
1824 fatal("no channel for session %d", s->self);
1825 channel_set_fds(s->chanid,
1826 fdout, fdin, fderr,
1827 fderr == -1 ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
1828 1,
1829 CHAN_SES_WINDOW_DEFAULT);
1830}
1831
1832/*
1833 * Function to perform pty cleanup. Also called if we get aborted abnormally
1834 * (e.g., due to a dropped connection).
1835 */
1836void
1837session_pty_cleanup2(void *session)
1838{
1839 Session *s = session;
1840
1841 if (s == NULL) {
1842 error("session_pty_cleanup: no session");
1843 return;
1844 }
1845 if (s->ttyfd == -1)
1846 return;
1847
1848 debug("session_pty_cleanup: session %d release %s", s->self, s->tty);
1849
1850 /* Record that the user has logged out. */
1851 if (s->pid != 0)
1852 record_logout(s->pid, s->tty, s->pw->pw_name);
1853
1854 /* Release the pseudo-tty. */
1855 if (getuid() == 0)
1856 pty_release(s->tty);
1857
1858 /*
1859 * Close the server side of the socket pairs. We must do this after
1860 * the pty cleanup, so that another process doesn't get this pty
1861 * while we're still cleaning up.
1862 */
1863 if (close(s->ptymaster) < 0)
1864 error("close(s->ptymaster/%d): %s", s->ptymaster, strerror(errno));
1865
1866 /* unlink pty from session */
1867 s->ttyfd = -1;
1868}
1869
1870void
1871session_pty_cleanup(void *session)
1872{
1873 PRIVSEP(session_pty_cleanup2(session));
1874}
1875
1876static char *
1877sig2name(int sig)
1878{
1879#define SSH_SIG(x) if (sig == SIG ## x) return #x
1880 SSH_SIG(ABRT);
1881 SSH_SIG(ALRM);
1882 SSH_SIG(FPE);
1883 SSH_SIG(HUP);
1884 SSH_SIG(ILL);
1885 SSH_SIG(INT);
1886 SSH_SIG(KILL);
1887 SSH_SIG(PIPE);
1888 SSH_SIG(QUIT);
1889 SSH_SIG(SEGV);
1890 SSH_SIG(TERM);
1891 SSH_SIG(USR1);
1892 SSH_SIG(USR2);
1893#undef SSH_SIG
1894 return "SIG@openssh.com";
1895}
1896
1897static void
1898session_exit_message(Session *s, int status)
1899{
1900 Channel *c;
1901
1902 if ((c = channel_lookup(s->chanid)) == NULL)
1903 fatal("session_exit_message: session %d: no channel %d",
1904 s->self, s->chanid);
1905 debug("session_exit_message: session %d channel %d pid %ld",
1906 s->self, s->chanid, (long)s->pid);
1907
1908 if (WIFEXITED(status)) {
1909 channel_request_start(s->chanid, "exit-status", 0);
1910 packet_put_int(WEXITSTATUS(status));
1911 packet_send();
1912 } else if (WIFSIGNALED(status)) {
1913 channel_request_start(s->chanid, "exit-signal", 0);
1914 packet_put_cstring(sig2name(WTERMSIG(status)));
1915#ifdef WCOREDUMP
1916 packet_put_char(WCOREDUMP(status));
1917#else /* WCOREDUMP */
1918 packet_put_char(0);
1919#endif /* WCOREDUMP */
1920 packet_put_cstring("");
1921 packet_put_cstring("");
1922 packet_send();
1923 } else {
1924 /* Some weird exit cause. Just exit. */
1925 packet_disconnect("wait returned status %04x.", status);
1926 }
1927
1928 /* disconnect channel */
1929 debug("session_exit_message: release channel %d", s->chanid);
1930 channel_cancel_cleanup(s->chanid);
1931 /*
1932 * emulate a write failure with 'chan_write_failed', nobody will be
1933 * interested in data we write.
1934 * Note that we must not call 'chan_read_failed', since there could
1935 * be some more data waiting in the pipe.
1936 */
1937 if (c->ostate != CHAN_OUTPUT_CLOSED)
1938 chan_write_failed(c);
1939 s->chanid = -1;
1940}
1941
1942void
1943session_close(Session *s)
1944{
1945 debug("session_close: session %d pid %ld", s->self, (long)s->pid);
1946 if (s->ttyfd != -1) {
1947 fatal_remove_cleanup(session_pty_cleanup, (void *)s);
1948 session_pty_cleanup(s);
1949 }
1950 if (s->term)
1951 xfree(s->term);
1952 if (s->display)
1953 xfree(s->display);
1954 if (s->auth_display)
1955 xfree(s->auth_display);
1956 if (s->auth_data)
1957 xfree(s->auth_data);
1958 if (s->auth_proto)
1959 xfree(s->auth_proto);
1960 s->used = 0;
1961 session_proctitle(s);
1962}
1963
1964void
1965session_close_by_pid(pid_t pid, int status)
1966{
1967 Session *s = session_by_pid(pid);
1968 if (s == NULL) {
1969 debug("session_close_by_pid: no session for pid %ld",
1970 (long)pid);
1971 return;
1972 }
1973 if (s->chanid != -1)
1974 session_exit_message(s, status);
1975 session_close(s);
1976}
1977
1978/*
1979 * this is called when a channel dies before
1980 * the session 'child' itself dies
1981 */
1982void
1983session_close_by_channel(int id, void *arg)
1984{
1985 Session *s = session_by_channel(id);
1986 if (s == NULL) {
1987 debug("session_close_by_channel: no session for id %d", id);
1988 return;
1989 }
1990 debug("session_close_by_channel: channel %d child %ld",
1991 id, (long)s->pid);
1992 if (s->pid != 0) {
1993 debug("session_close_by_channel: channel %d: has child", id);
1994 /*
1995 * delay detach of session, but release pty, since
1996 * the fd's to the child are already closed
1997 */
1998 if (s->ttyfd != -1) {
1999 fatal_remove_cleanup(session_pty_cleanup, (void *)s);
2000 session_pty_cleanup(s);
2001 }
2002 return;
2003 }
2004 /* detach by removing callback */
2005 channel_cancel_cleanup(s->chanid);
2006 s->chanid = -1;
2007 session_close(s);
2008}
2009
2010void
2011session_destroy_all(void (*closefunc)(Session *))
2012{
2013 int i;
2014 for (i = 0; i < MAX_SESSIONS; i++) {
2015 Session *s = &sessions[i];
2016 if (s->used) {
2017 if (closefunc != NULL)
2018 closefunc(s);
2019 else
2020 session_close(s);
2021 }
2022 }
2023}
2024
2025static char *
2026session_tty_list(void)
2027{
2028 static char buf[1024];
2029 int i;
2030 buf[0] = '\0';
2031 for (i = 0; i < MAX_SESSIONS; i++) {
2032 Session *s = &sessions[i];
2033 if (s->used && s->ttyfd != -1) {
2034 if (buf[0] != '\0')
2035 strlcat(buf, ",", sizeof buf);
2036 strlcat(buf, strrchr(s->tty, '/') + 1, sizeof buf);
2037 }
2038 }
2039 if (buf[0] == '\0')
2040 strlcpy(buf, "notty", sizeof buf);
2041 return buf;
2042}
2043
2044void
2045session_proctitle(Session *s)
2046{
2047 if (s->pw == NULL)
2048 error("no user for session %d", s->self);
2049 else
2050 setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
2051}
2052
2053int
2054session_setup_x11fwd(Session *s)
2055{
2056 struct stat st;
2057 char display[512], auth_display[512];
2058 char hostname[MAXHOSTNAMELEN];
2059
2060 if (no_x11_forwarding_flag) {
2061 packet_send_debug("X11 forwarding disabled in user configuration file.");
2062 return 0;
2063 }
2064 if (!options.x11_forwarding) {
2065 debug("X11 forwarding disabled in server configuration file.");
2066 return 0;
2067 }
2068 if (!options.xauth_location ||
2069 (stat(options.xauth_location, &st) == -1)) {
2070 packet_send_debug("No xauth program; cannot forward with spoofing.");
2071 return 0;
2072 }
2073 if (options.use_login) {
2074 packet_send_debug("X11 forwarding disabled; "
2075 "not compatible with UseLogin=yes.");
2076 return 0;
2077 }
2078 if (s->display != NULL) {
2079 debug("X11 display already set.");
2080 return 0;
2081 }
2082 if (x11_create_display_inet(options.x11_display_offset,
2083 options.x11_use_localhost, s->single_connection,
2084 &s->display_number) == -1) {
2085 debug("x11_create_display_inet failed.");
2086 return 0;
2087 }
2088
2089 /* Set up a suitable value for the DISPLAY variable. */
2090 if (gethostname(hostname, sizeof(hostname)) < 0)
2091 fatal("gethostname: %.100s", strerror(errno));
2092 /*
2093 * auth_display must be used as the displayname when the
2094 * authorization entry is added with xauth(1). This will be
2095 * different than the DISPLAY string for localhost displays.
2096 */
2097 if (options.x11_use_localhost) {
2098 snprintf(display, sizeof display, "localhost:%u.%u",
2099 s->display_number, s->screen);
2100 snprintf(auth_display, sizeof auth_display, "unix:%u.%u",
2101 s->display_number, s->screen);
2102 s->display = xstrdup(display);
2103 s->auth_display = xstrdup(auth_display);
2104 } else {
2105#ifdef IPADDR_IN_DISPLAY
2106 struct hostent *he;
2107 struct in_addr my_addr;
2108
2109 he = gethostbyname(hostname);
2110 if (he == NULL) {
2111 error("Can't get IP address for X11 DISPLAY.");
2112 packet_send_debug("Can't get IP address for X11 DISPLAY.");
2113 return 0;
2114 }
2115 memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr));
2116 snprintf(display, sizeof display, "%.50s:%u.%u", inet_ntoa(my_addr),
2117 s->display_number, s->screen);
2118#else
2119 snprintf(display, sizeof display, "%.400s:%u.%u", hostname,
2120 s->display_number, s->screen);
2121#endif
2122 s->display = xstrdup(display);
2123 s->auth_display = xstrdup(display);
2124 }
2125
2126 return 1;
2127}
2128
2129static void
2130do_authenticated2(Authctxt *authctxt)
2131{
2132 server_loop2(authctxt);
2133}