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merging in Simon Wilkinson's latest patch (openssh-3.1p1-gssapi-20020323.diff)
[gssapi-openssh.git] / openssh / session.c
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3c0ef626 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"
e9702f7d 36RCSID("$OpenBSD: session.c,v 1.128 2002/02/16 00:51:44 markus Exp $");
3c0ef626 37
38#include "ssh.h"
39#include "ssh1.h"
40#include "ssh2.h"
41#include "xmalloc.h"
42#include "sshpty.h"
43#include "packet.h"
44#include "buffer.h"
45#include "mpaux.h"
46#include "uidswap.h"
47#include "compat.h"
48#include "channels.h"
49#include "bufaux.h"
50#include "auth.h"
51#include "auth-options.h"
52#include "pathnames.h"
53#include "log.h"
54#include "servconf.h"
55#include "sshlogin.h"
56#include "serverloop.h"
57#include "canohost.h"
58#include "session.h"
59
5598e598 60#ifdef GSSAPI
61#include "ssh-gss.h"
62#endif
63
3c0ef626 64#ifdef HAVE_CYGWIN
65#include <windows.h>
66#include <sys/cygwin.h>
67#define is_winnt (GetVersion() < 0x80000000)
68#endif
69
3c0ef626 70/* types */
71
72#define TTYSZ 64
73typedef struct Session Session;
74struct Session {
75 int used;
76 int self;
77 struct passwd *pw;
78 Authctxt *authctxt;
79 pid_t pid;
80 /* tty */
81 char *term;
82 int ptyfd, ttyfd, ptymaster;
83 int row, col, xpixel, ypixel;
84 char tty[TTYSZ];
85 /* X11 */
e9702f7d 86 int display_number;
3c0ef626 87 char *display;
88 int screen;
e9702f7d 89 char *auth_display;
3c0ef626 90 char *auth_proto;
91 char *auth_data;
92 int single_connection;
93 /* proto 2 */
94 int chanid;
95 int is_subsystem;
96};
97
98/* func */
99
100Session *session_new(void);
101void session_set_fds(Session *, int, int, int);
102static void session_pty_cleanup(void *);
103void session_proctitle(Session *);
104int session_setup_x11fwd(Session *);
105void do_exec_pty(Session *, const char *);
106void do_exec_no_pty(Session *, const char *);
107void do_exec(Session *, const char *);
108void do_login(Session *, const char *);
109#ifdef LOGIN_NEEDS_UTMPX
110static void do_pre_login(Session *s);
111#endif
112void do_child(Session *, const char *);
113void do_motd(void);
114int check_quietlogin(Session *, const char *);
115
116static void do_authenticated1(Authctxt *);
117static void do_authenticated2(Authctxt *);
118
119static void session_close(Session *);
120static int session_pty_req(Session *);
121
122/* import */
123extern ServerOptions options;
124extern char *__progname;
125extern int log_stderr;
126extern int debug_flag;
127extern u_int utmp_len;
128extern int startup_pipe;
129extern void destroy_sensitive_data(void);
130
131/* original command from peer. */
132const char *original_command = NULL;
133
134/* data */
135#define MAX_SESSIONS 10
136Session sessions[MAX_SESSIONS];
137
138#ifdef WITH_AIXAUTHENTICATE
139char *aixloginmsg;
140#endif /* WITH_AIXAUTHENTICATE */
141
142#ifdef HAVE_LOGIN_CAP
143static login_cap_t *lc;
144#endif
145
146void
147do_authenticated(Authctxt *authctxt)
148{
149 /*
150 * Cancel the alarm we set to limit the time taken for
151 * authentication.
152 */
153 alarm(0);
154 if (startup_pipe != -1) {
155 close(startup_pipe);
156 startup_pipe = -1;
157 }
158#if defined(HAVE_LOGIN_CAP) && defined(HAVE_PW_CLASS_IN_PASSWD)
159 if ((lc = login_getclass(authctxt->pw->pw_class)) == NULL) {
160 error("unable to get login class");
161 return;
162 }
163#ifdef BSD_AUTH
164 if (auth_approval(NULL, lc, authctxt->pw->pw_name, "ssh") <= 0) {
165 packet_disconnect("Approval failure for %s",
166 authctxt->pw->pw_name);
167 }
168#endif
169#endif
170#ifdef WITH_AIXAUTHENTICATE
171 /* We don't have a pty yet, so just label the line as "ssh" */
172 if (loginsuccess(authctxt->user,
e9702f7d 173 get_canonical_hostname(options.verify_reverse_mapping),
3c0ef626 174 "ssh", &aixloginmsg) < 0)
175 aixloginmsg = NULL;
176#endif /* WITH_AIXAUTHENTICATE */
177
178 /* setup the channel layer */
179 if (!no_port_forwarding_flag && options.allow_tcp_forwarding)
180 channel_permit_all_opens();
181
182 if (compat20)
183 do_authenticated2(authctxt);
184 else
185 do_authenticated1(authctxt);
186
187 /* remove agent socket */
188 if (auth_get_socket_name())
189 auth_sock_cleanup_proc(authctxt->pw);
190#ifdef KRB4
191 if (options.kerberos_ticket_cleanup)
192 krb4_cleanup_proc(authctxt);
193#endif
194#ifdef KRB5
195 if (options.kerberos_ticket_cleanup)
196 krb5_cleanup_proc(authctxt);
197#endif
198}
199
200/*
201 * Prepares for an interactive session. This is called after the user has
202 * been successfully authenticated. During this message exchange, pseudo
203 * terminals are allocated, X11, TCP/IP, and authentication agent forwardings
204 * are requested, etc.
205 */
206static void
207do_authenticated1(Authctxt *authctxt)
208{
209 Session *s;
210 char *command;
e9702f7d 211 int success, type, screen_flag;
3c0ef626 212 int compression_level = 0, enable_compression_after_reply = 0;
213 u_int proto_len, data_len, dlen;
214
215 s = session_new();
216 s->authctxt = authctxt;
217 s->pw = authctxt->pw;
218
219 /*
220 * We stay in this loop until the client requests to execute a shell
221 * or a command.
222 */
223 for (;;) {
224 success = 0;
225
226 /* Get a packet from the client. */
e9702f7d 227 type = packet_read();
3c0ef626 228
229 /* Process the packet. */
230 switch (type) {
231 case SSH_CMSG_REQUEST_COMPRESSION:
3c0ef626 232 compression_level = packet_get_int();
e9702f7d 233 packet_check_eom();
3c0ef626 234 if (compression_level < 1 || compression_level > 9) {
235 packet_send_debug("Received illegal compression level %d.",
e9702f7d 236 compression_level);
3c0ef626 237 break;
238 }
239 /* Enable compression after we have responded with SUCCESS. */
240 enable_compression_after_reply = 1;
241 success = 1;
242 break;
243
244 case SSH_CMSG_REQUEST_PTY:
245 success = session_pty_req(s);
246 break;
247
248 case SSH_CMSG_X11_REQUEST_FORWARDING:
249 s->auth_proto = packet_get_string(&proto_len);
250 s->auth_data = packet_get_string(&data_len);
251
252 screen_flag = packet_get_protocol_flags() &
253 SSH_PROTOFLAG_SCREEN_NUMBER;
254 debug2("SSH_PROTOFLAG_SCREEN_NUMBER: %d", screen_flag);
255
256 if (packet_remaining() == 4) {
257 if (!screen_flag)
258 debug2("Buggy client: "
259 "X11 screen flag missing");
260 s->screen = packet_get_int();
261 } else {
262 s->screen = 0;
263 }
e9702f7d 264 packet_check_eom();
3c0ef626 265 success = session_setup_x11fwd(s);
266 if (!success) {
267 xfree(s->auth_proto);
268 xfree(s->auth_data);
269 s->auth_proto = NULL;
270 s->auth_data = NULL;
271 }
272 break;
273
274 case SSH_CMSG_AGENT_REQUEST_FORWARDING:
275 if (no_agent_forwarding_flag || compat13) {
276 debug("Authentication agent forwarding not permitted for this authentication.");
277 break;
278 }
279 debug("Received authentication agent forwarding request.");
280 success = auth_input_request_forwarding(s->pw);
281 break;
282
283 case SSH_CMSG_PORT_FORWARD_REQUEST:
284 if (no_port_forwarding_flag) {
285 debug("Port forwarding not permitted for this authentication.");
286 break;
287 }
288 if (!options.allow_tcp_forwarding) {
289 debug("Port forwarding not permitted.");
290 break;
291 }
292 debug("Received TCP/IP port forwarding request.");
293 channel_input_port_forward_request(s->pw->pw_uid == 0, options.gateway_ports);
294 success = 1;
295 break;
296
297 case SSH_CMSG_MAX_PACKET_SIZE:
298 if (packet_set_maxsize(packet_get_int()) > 0)
299 success = 1;
300 break;
e9702f7d 301
3c0ef626 302#if defined(AFS) || defined(KRB5)
303 case SSH_CMSG_HAVE_KERBEROS_TGT:
304 if (!options.kerberos_tgt_passing) {
305 verbose("Kerberos TGT passing disabled.");
306 } else {
307 char *kdata = packet_get_string(&dlen);
e9702f7d 308 packet_check_eom();
309
3c0ef626 310 /* XXX - 0x41, see creds_to_radix version */
311 if (kdata[0] != 0x41) {
312#ifdef KRB5
313 krb5_data tgt;
314 tgt.data = kdata;
315 tgt.length = dlen;
e9702f7d 316
3c0ef626 317 if (auth_krb5_tgt(s->authctxt, &tgt))
318 success = 1;
319 else
320 verbose("Kerberos v5 TGT refused for %.100s", s->authctxt->user);
321#endif /* KRB5 */
322 } else {
323#ifdef AFS
324 if (auth_krb4_tgt(s->authctxt, kdata))
325 success = 1;
326 else
327 verbose("Kerberos v4 TGT refused for %.100s", s->authctxt->user);
328#endif /* AFS */
329 }
330 xfree(kdata);
331 }
332 break;
333#endif /* AFS || KRB5 */
e9702f7d 334
3c0ef626 335#ifdef AFS
336 case SSH_CMSG_HAVE_AFS_TOKEN:
337 if (!options.afs_token_passing || !k_hasafs()) {
338 verbose("AFS token passing disabled.");
339 } else {
340 /* Accept AFS token. */
341 char *token = packet_get_string(&dlen);
e9702f7d 342 packet_check_eom();
343
3c0ef626 344 if (auth_afs_token(s->authctxt, token))
345 success = 1;
346 else
347 verbose("AFS token refused for %.100s",
348 s->authctxt->user);
349 xfree(token);
350 }
351 break;
352#endif /* AFS */
353
354 case SSH_CMSG_EXEC_SHELL:
355 case SSH_CMSG_EXEC_CMD:
356 if (type == SSH_CMSG_EXEC_CMD) {
357 command = packet_get_string(&dlen);
358 debug("Exec command '%.500s'", command);
359 do_exec(s, command);
360 xfree(command);
361 } else {
362 do_exec(s, NULL);
363 }
e9702f7d 364 packet_check_eom();
3c0ef626 365 session_close(s);
366 return;
367
368 default:
369 /*
370 * Any unknown messages in this phase are ignored,
371 * and a failure message is returned.
372 */
373 log("Unknown packet type received after authentication: %d", type);
374 }
375 packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE);
376 packet_send();
377 packet_write_wait();
378
379 /* Enable compression now that we have replied if appropriate. */
380 if (enable_compression_after_reply) {
381 enable_compression_after_reply = 0;
382 packet_start_compression(compression_level);
383 }
384 }
385}
386
387/*
388 * This is called to fork and execute a command when we have no tty. This
389 * will call do_child from the child, and server_loop from the parent after
390 * setting up file descriptors and such.
391 */
392void
393do_exec_no_pty(Session *s, const char *command)
394{
395 int pid;
396
397#ifdef USE_PIPES
398 int pin[2], pout[2], perr[2];
399 /* Allocate pipes for communicating with the program. */
400 if (pipe(pin) < 0 || pipe(pout) < 0 || pipe(perr) < 0)
401 packet_disconnect("Could not create pipes: %.100s",
402 strerror(errno));
403#else /* USE_PIPES */
404 int inout[2], err[2];
405 /* Uses socket pairs to communicate with the program. */
406 if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0 ||
407 socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0)
408 packet_disconnect("Could not create socket pairs: %.100s",
409 strerror(errno));
410#endif /* USE_PIPES */
411 if (s == NULL)
412 fatal("do_exec_no_pty: no session");
413
414 session_proctitle(s);
415
5598e598 416#if defined(GSSAPI)
417 temporarily_use_uid(s->pw);
418 ssh_gssapi_storecreds();
419 restore_uid();
420#endif
421
3c0ef626 422#if defined(USE_PAM)
423 do_pam_session(s->pw->pw_name, NULL);
424 do_pam_setcred(1);
425 if (is_pam_password_change_required())
426 packet_disconnect("Password change required but no "
427 "TTY available");
428#endif /* USE_PAM */
429
430 /* Fork the child. */
431 if ((pid = fork()) == 0) {
432 /* Child. Reinitialize the log since the pid has changed. */
433 log_init(__progname, options.log_level, options.log_facility, log_stderr);
434
435 /*
436 * Create a new session and process group since the 4.4BSD
437 * setlogin() affects the entire process group.
438 */
439 if (setsid() < 0)
440 error("setsid failed: %.100s", strerror(errno));
441
442#ifdef USE_PIPES
443 /*
444 * Redirect stdin. We close the parent side of the socket
445 * pair, and make the child side the standard input.
446 */
447 close(pin[1]);
448 if (dup2(pin[0], 0) < 0)
449 perror("dup2 stdin");
450 close(pin[0]);
451
452 /* Redirect stdout. */
453 close(pout[0]);
454 if (dup2(pout[1], 1) < 0)
455 perror("dup2 stdout");
456 close(pout[1]);
457
458 /* Redirect stderr. */
459 close(perr[0]);
460 if (dup2(perr[1], 2) < 0)
461 perror("dup2 stderr");
462 close(perr[1]);
463#else /* USE_PIPES */
464 /*
465 * Redirect stdin, stdout, and stderr. Stdin and stdout will
466 * use the same socket, as some programs (particularly rdist)
467 * seem to depend on it.
468 */
469 close(inout[1]);
470 close(err[1]);
471 if (dup2(inout[0], 0) < 0) /* stdin */
472 perror("dup2 stdin");
473 if (dup2(inout[0], 1) < 0) /* stdout. Note: same socket as stdin. */
474 perror("dup2 stdout");
475 if (dup2(err[0], 2) < 0) /* stderr */
476 perror("dup2 stderr");
477#endif /* USE_PIPES */
478
479 /* Do processing for the child (exec command etc). */
480 do_child(s, command);
481 /* NOTREACHED */
482 }
483#ifdef HAVE_CYGWIN
484 if (is_winnt)
485 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
486#endif
487 if (pid < 0)
488 packet_disconnect("fork failed: %.100s", strerror(errno));
489 s->pid = pid;
490 /* Set interactive/non-interactive mode. */
491 packet_set_interactive(s->display != NULL);
492#ifdef USE_PIPES
493 /* We are the parent. Close the child sides of the pipes. */
494 close(pin[0]);
495 close(pout[1]);
496 close(perr[1]);
497
498 if (compat20) {
499 session_set_fds(s, pin[1], pout[0], s->is_subsystem ? -1 : perr[0]);
500 } else {
501 /* Enter the interactive session. */
502 server_loop(pid, pin[1], pout[0], perr[0]);
503 /* server_loop has closed pin[1], pout[0], and perr[0]. */
504 }
505#else /* USE_PIPES */
506 /* We are the parent. Close the child sides of the socket pairs. */
507 close(inout[0]);
508 close(err[0]);
509
510 /*
511 * Enter the interactive session. Note: server_loop must be able to
512 * handle the case that fdin and fdout are the same.
513 */
514 if (compat20) {
515 session_set_fds(s, inout[1], inout[1], s->is_subsystem ? -1 : err[1]);
516 } else {
517 server_loop(pid, inout[1], inout[1], err[1]);
518 /* server_loop has closed inout[1] and err[1]. */
519 }
520#endif /* USE_PIPES */
521}
522
523/*
524 * This is called to fork and execute a command when we have a tty. This
525 * will call do_child from the child, and server_loop from the parent after
526 * setting up file descriptors, controlling tty, updating wtmp, utmp,
527 * lastlog, and other such operations.
528 */
529void
530do_exec_pty(Session *s, const char *command)
531{
532 int fdout, ptyfd, ttyfd, ptymaster;
533 pid_t pid;
534
535 if (s == NULL)
536 fatal("do_exec_pty: no session");
537 ptyfd = s->ptyfd;
538 ttyfd = s->ttyfd;
539
5598e598 540#if defined(GSSAPI)
541 temporarily_use_uid(s->pw);
542 ssh_gssapi_storecreds();
543 restore_uid();
544#endif
545
3c0ef626 546#if defined(USE_PAM)
547 do_pam_session(s->pw->pw_name, s->tty);
548 do_pam_setcred(1);
549#endif
550
551 /* Fork the child. */
552 if ((pid = fork()) == 0) {
553
554 /* Child. Reinitialize the log because the pid has changed. */
555 log_init(__progname, options.log_level, options.log_facility, log_stderr);
556 /* Close the master side of the pseudo tty. */
557 close(ptyfd);
558
559 /* Make the pseudo tty our controlling tty. */
560 pty_make_controlling_tty(&ttyfd, s->tty);
561
562 /* Redirect stdin/stdout/stderr from the pseudo tty. */
563 if (dup2(ttyfd, 0) < 0)
564 error("dup2 stdin: %s", strerror(errno));
565 if (dup2(ttyfd, 1) < 0)
566 error("dup2 stdout: %s", strerror(errno));
567 if (dup2(ttyfd, 2) < 0)
568 error("dup2 stderr: %s", strerror(errno));
569
570 /* Close the extra descriptor for the pseudo tty. */
571 close(ttyfd);
572
573 /* record login, etc. similar to login(1) */
574#ifndef HAVE_OSF_SIA
575 if (!(options.use_login && command == NULL))
576 do_login(s, command);
577# ifdef LOGIN_NEEDS_UTMPX
578 else
579 do_pre_login(s);
580# endif
581#endif
582
583 /* Do common processing for the child, such as execing the command. */
584 do_child(s, command);
585 /* NOTREACHED */
586 }
587#ifdef HAVE_CYGWIN
588 if (is_winnt)
589 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
590#endif
591 if (pid < 0)
592 packet_disconnect("fork failed: %.100s", strerror(errno));
593 s->pid = pid;
594
595 /* Parent. Close the slave side of the pseudo tty. */
596 close(ttyfd);
597
598 /*
599 * Create another descriptor of the pty master side for use as the
600 * standard input. We could use the original descriptor, but this
601 * simplifies code in server_loop. The descriptor is bidirectional.
602 */
603 fdout = dup(ptyfd);
604 if (fdout < 0)
605 packet_disconnect("dup #1 failed: %.100s", strerror(errno));
606
607 /* we keep a reference to the pty master */
608 ptymaster = dup(ptyfd);
609 if (ptymaster < 0)
610 packet_disconnect("dup #2 failed: %.100s", strerror(errno));
611 s->ptymaster = ptymaster;
612
613 /* Enter interactive session. */
614 packet_set_interactive(1);
615 if (compat20) {
616 session_set_fds(s, ptyfd, fdout, -1);
617 } else {
618 server_loop(pid, ptyfd, fdout, -1);
619 /* server_loop _has_ closed ptyfd and fdout. */
620 }
621}
622
623#ifdef LOGIN_NEEDS_UTMPX
624static void
625do_pre_login(Session *s)
626{
627 socklen_t fromlen;
628 struct sockaddr_storage from;
629 pid_t pid = getpid();
630
631 /*
632 * Get IP address of client. If the connection is not a socket, let
633 * the address be 0.0.0.0.
634 */
635 memset(&from, 0, sizeof(from));
636 if (packet_connection_is_on_socket()) {
637 fromlen = sizeof(from);
638 if (getpeername(packet_get_connection_in(),
e9702f7d 639 (struct sockaddr *) & from, &fromlen) < 0) {
3c0ef626 640 debug("getpeername: %.100s", strerror(errno));
641 fatal_cleanup();
642 }
643 }
644
645 record_utmp_only(pid, s->tty, s->pw->pw_name,
e9702f7d 646 get_remote_name_or_ip(utmp_len, options.verify_reverse_mapping),
3c0ef626 647 (struct sockaddr *)&from);
648}
649#endif
650
651/*
652 * This is called to fork and execute a command. If another command is
653 * to be forced, execute that instead.
654 */
655void
656do_exec(Session *s, const char *command)
657{
658 if (forced_command) {
659 original_command = command;
660 command = forced_command;
661 debug("Forced command '%.900s'", command);
662 }
663
664 if (s->ttyfd != -1)
665 do_exec_pty(s, command);
666 else
667 do_exec_no_pty(s, command);
668
669 original_command = NULL;
670}
671
e9702f7d 672
3c0ef626 673/* administrative, login(1)-like work */
674void
675do_login(Session *s, const char *command)
676{
677 char *time_string;
678 char hostname[MAXHOSTNAMELEN];
679 socklen_t fromlen;
680 struct sockaddr_storage from;
681 time_t last_login_time;
682 struct passwd * pw = s->pw;
683 pid_t pid = getpid();
684
685 /*
686 * Get IP address of client. If the connection is not a socket, let
687 * the address be 0.0.0.0.
688 */
689 memset(&from, 0, sizeof(from));
690 if (packet_connection_is_on_socket()) {
691 fromlen = sizeof(from);
692 if (getpeername(packet_get_connection_in(),
e9702f7d 693 (struct sockaddr *) & from, &fromlen) < 0) {
3c0ef626 694 debug("getpeername: %.100s", strerror(errno));
695 fatal_cleanup();
696 }
697 }
698
699 /* Get the time and hostname when the user last logged in. */
700 if (options.print_lastlog) {
701 hostname[0] = '\0';
702 last_login_time = get_last_login_time(pw->pw_uid, pw->pw_name,
703 hostname, sizeof(hostname));
704 }
705
706 /* Record that there was a login on that tty from the remote host. */
707 record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
e9702f7d 708 get_remote_name_or_ip(utmp_len, options.verify_reverse_mapping),
3c0ef626 709 (struct sockaddr *)&from);
710
711#ifdef USE_PAM
712 /*
713 * If password change is needed, do it now.
714 * This needs to occur before the ~/.hushlogin check.
715 */
716 if (is_pam_password_change_required()) {
717 print_pam_messages();
718 do_pam_chauthtok();
719 }
720#endif
721
722 if (check_quietlogin(s, command))
723 return;
724
725#ifdef USE_PAM
726 if (!is_pam_password_change_required())
727 print_pam_messages();
728#endif /* USE_PAM */
729#ifdef WITH_AIXAUTHENTICATE
730 if (aixloginmsg && *aixloginmsg)
731 printf("%s\n", aixloginmsg);
732#endif /* WITH_AIXAUTHENTICATE */
733
734 if (options.print_lastlog && last_login_time != 0) {
735 time_string = ctime(&last_login_time);
736 if (strchr(time_string, '\n'))
737 *strchr(time_string, '\n') = 0;
738 if (strcmp(hostname, "") == 0)
739 printf("Last login: %s\r\n", time_string);
740 else
741 printf("Last login: %s from %s\r\n", time_string, hostname);
742 }
743
744 do_motd();
745}
746
747/*
748 * Display the message of the day.
749 */
750void
751do_motd(void)
752{
753 FILE *f;
754 char buf[256];
755
756 if (options.print_motd) {
757#ifdef HAVE_LOGIN_CAP
758 f = fopen(login_getcapstr(lc, "welcome", "/etc/motd",
759 "/etc/motd"), "r");
760#else
761 f = fopen("/etc/motd", "r");
762#endif
763 if (f) {
764 while (fgets(buf, sizeof(buf), f))
765 fputs(buf, stdout);
766 fclose(f);
767 }
768 }
769}
770
771
772/*
773 * Check for quiet login, either .hushlogin or command given.
774 */
775int
776check_quietlogin(Session *s, const char *command)
777{
778 char buf[256];
779 struct passwd *pw = s->pw;
780 struct stat st;
781
782 /* Return 1 if .hushlogin exists or a command given. */
783 if (command != NULL)
784 return 1;
785 snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
786#ifdef HAVE_LOGIN_CAP
787 if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
788 return 1;
789#else
790 if (stat(buf, &st) >= 0)
791 return 1;
792#endif
793 return 0;
794}
795
796/*
797 * Sets the value of the given variable in the environment. If the variable
798 * already exists, its value is overriden.
799 */
5598e598 800void
3c0ef626 801child_set_env(char ***envp, u_int *envsizep, const char *name,
e9702f7d 802 const char *value)
3c0ef626 803{
804 u_int i, namelen;
805 char **env;
806
807 /*
808 * Find the slot where the value should be stored. If the variable
809 * already exists, we reuse the slot; otherwise we append a new slot
810 * at the end of the array, expanding if necessary.
811 */
812 env = *envp;
813 namelen = strlen(name);
814 for (i = 0; env[i]; i++)
815 if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
816 break;
817 if (env[i]) {
818 /* Reuse the slot. */
819 xfree(env[i]);
820 } else {
821 /* New variable. Expand if necessary. */
822 if (i >= (*envsizep) - 1) {
823 (*envsizep) += 50;
824 env = (*envp) = xrealloc(env, (*envsizep) * sizeof(char *));
825 }
826 /* Need to set the NULL pointer at end of array beyond the new slot. */
827 env[i + 1] = NULL;
828 }
829
830 /* Allocate space and format the variable in the appropriate slot. */
831 env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
832 snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
833}
834
835/*
836 * Reads environment variables from the given file and adds/overrides them
837 * into the environment. If the file does not exist, this does nothing.
838 * Otherwise, it must consist of empty lines, comments (line starts with '#')
839 * and assignments of the form name=value. No other forms are allowed.
840 */
841static void
842read_environment_file(char ***env, u_int *envsize,
e9702f7d 843 const char *filename)
3c0ef626 844{
845 FILE *f;
846 char buf[4096];
847 char *cp, *value;
848
849 f = fopen(filename, "r");
850 if (!f)
851 return;
852
853 while (fgets(buf, sizeof(buf), f)) {
854 for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
855 ;
856 if (!*cp || *cp == '#' || *cp == '\n')
857 continue;
858 if (strchr(cp, '\n'))
859 *strchr(cp, '\n') = '\0';
860 value = strchr(cp, '=');
861 if (value == NULL) {
862 fprintf(stderr, "Bad line in %.100s: %.200s\n", filename, buf);
863 continue;
864 }
865 /*
866 * Replace the equals sign by nul, and advance value to
867 * the value string.
868 */
869 *value = '\0';
870 value++;
871 child_set_env(env, envsize, cp, value);
872 }
873 fclose(f);
874}
875
e9702f7d 876void copy_environment(char **source, char ***env, u_int *envsize)
3c0ef626 877{
e9702f7d 878 char *var_name, *var_val;
3c0ef626 879 int i;
880
e9702f7d 881 if (source == NULL)
3c0ef626 882 return;
883
e9702f7d 884 for(i = 0; source[i] != NULL; i++) {
885 var_name = xstrdup(source[i]);
886 if ((var_val = strstr(var_name, "=")) == NULL) {
887 xfree(var_name);
3c0ef626 888 continue;
3c0ef626 889 }
e9702f7d 890 *var_val++ = '\0';
3c0ef626 891
e9702f7d 892 debug3("Copy environment: %s=%s", var_name, var_val);
893 child_set_env(env, envsize, var_name, var_val);
894
895 xfree(var_name);
3c0ef626 896 }
3c0ef626 897}
898
e9702f7d 899static char **
900do_setup_env(Session *s, const char *shell)
3c0ef626 901{
3c0ef626 902 char buf[256];
e9702f7d 903 u_int i, envsize;
3c0ef626 904 char **env;
e9702f7d 905 struct passwd *pw = s->pw;
3c0ef626 906
907 /* Initialize the environment. */
908 envsize = 100;
909 env = xmalloc(envsize * sizeof(char *));
910 env[0] = NULL;
911
912#ifdef HAVE_CYGWIN
913 /*
914 * The Windows environment contains some setting which are
915 * important for a running system. They must not be dropped.
916 */
e9702f7d 917 copy_environment(environ, &env, &envsize);
3c0ef626 918#endif
919
5598e598 920#ifdef GSSAPI
921 /* Allow any GSSAPI methods that we've used to alter
922 * the childs environment as they see fit
923 */
924 ssh_gssapi_do_child(&env,&envsize);
925#endif
926
3c0ef626 927 if (!options.use_login) {
928 /* Set basic environment. */
929 child_set_env(&env, &envsize, "USER", pw->pw_name);
930 child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
931 child_set_env(&env, &envsize, "HOME", pw->pw_dir);
932#ifdef HAVE_LOGIN_CAP
933 (void) setusercontext(lc, pw, pw->pw_uid, LOGIN_SETPATH);
934 child_set_env(&env, &envsize, "PATH", getenv("PATH"));
935#else /* HAVE_LOGIN_CAP */
936# ifndef HAVE_CYGWIN
937 /*
938 * There's no standard path on Windows. The path contains
939 * important components pointing to the system directories,
940 * needed for loading shared libraries. So the path better
941 * remains intact here.
942 */
943 child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
944# endif /* HAVE_CYGWIN */
945#endif /* HAVE_LOGIN_CAP */
946
947 snprintf(buf, sizeof buf, "%.200s/%.50s",
948 _PATH_MAILDIR, pw->pw_name);
949 child_set_env(&env, &envsize, "MAIL", buf);
950
951 /* Normal systems set SHELL by default. */
952 child_set_env(&env, &envsize, "SHELL", shell);
953 }
954 if (getenv("TZ"))
955 child_set_env(&env, &envsize, "TZ", getenv("TZ"));
956
957 /* Set custom environment options from RSA authentication. */
958 if (!options.use_login) {
959 while (custom_environment) {
960 struct envstring *ce = custom_environment;
961 char *s = ce->s;
e9702f7d 962
3c0ef626 963 for (i = 0; s[i] != '=' && s[i]; i++)
964 ;
965 if (s[i] == '=') {
966 s[i] = 0;
967 child_set_env(&env, &envsize, s, s + i + 1);
968 }
969 custom_environment = ce->next;
970 xfree(ce->s);
971 xfree(ce);
972 }
973 }
974
975 snprintf(buf, sizeof buf, "%.50s %d %d",
e9702f7d 976 get_remote_ipaddr(), get_remote_port(), get_local_port());
3c0ef626 977 child_set_env(&env, &envsize, "SSH_CLIENT", buf);
978
979 if (s->ttyfd != -1)
980 child_set_env(&env, &envsize, "SSH_TTY", s->tty);
981 if (s->term)
982 child_set_env(&env, &envsize, "TERM", s->term);
983 if (s->display)
984 child_set_env(&env, &envsize, "DISPLAY", s->display);
985 if (original_command)
986 child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
987 original_command);
988
989#ifdef _AIX
e9702f7d 990 {
991 char *cp;
992
993 if ((cp = getenv("AUTHSTATE")) != NULL)
994 child_set_env(&env, &envsize, "AUTHSTATE", cp);
995 if ((cp = getenv("KRB5CCNAME")) != NULL)
996 child_set_env(&env, &envsize, "KRB5CCNAME", cp);
997 read_environment_file(&env, &envsize, "/etc/environment");
998 }
3c0ef626 999#endif
1000#ifdef KRB4
1001 if (s->authctxt->krb4_ticket_file)
1002 child_set_env(&env, &envsize, "KRBTKFILE",
1003 s->authctxt->krb4_ticket_file);
1004#endif
1005#ifdef KRB5
1006 if (s->authctxt->krb5_ticket_file)
1007 child_set_env(&env, &envsize, "KRB5CCNAME",
1008 s->authctxt->krb5_ticket_file);
1009#endif
1010#ifdef USE_PAM
1011 /* Pull in any environment variables that may have been set by PAM. */
e9702f7d 1012 copy_environment(fetch_pam_environment(), &env, &envsize);
3c0ef626 1013#endif /* USE_PAM */
1014
1015 if (auth_get_socket_name() != NULL)
1016 child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
e9702f7d 1017 auth_get_socket_name());
3c0ef626 1018
1019 /* read $HOME/.ssh/environment. */
1020 if (!options.use_login) {
1021 snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
1022 pw->pw_dir);
1023 read_environment_file(&env, &envsize, buf);
1024 }
1025 if (debug_flag) {
1026 /* dump the environment */
1027 fprintf(stderr, "Environment:\n");
1028 for (i = 0; env[i]; i++)
1029 fprintf(stderr, " %.200s\n", env[i]);
1030 }
e9702f7d 1031 return env;
1032}
1033
1034/*
1035 * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found
1036 * first in this order).
1037 */
1038static void
1039do_rc_files(Session *s, const char *shell)
1040{
1041 FILE *f = NULL;
1042 char cmd[1024];
1043 int do_xauth;
1044 struct stat st;
1045
1046 do_xauth =
1047 s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
1048
1049 /* ignore _PATH_SSH_USER_RC for subsystems */
1050 if (!s->is_subsystem && (stat(_PATH_SSH_USER_RC, &st) >= 0)) {
1051 snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
1052 shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
1053 if (debug_flag)
1054 fprintf(stderr, "Running %s\n", cmd);
1055 f = popen(cmd, "w");
1056 if (f) {
1057 if (do_xauth)
1058 fprintf(f, "%s %s\n", s->auth_proto,
1059 s->auth_data);
1060 pclose(f);
1061 } else
1062 fprintf(stderr, "Could not run %s\n",
1063 _PATH_SSH_USER_RC);
1064 } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
1065 if (debug_flag)
1066 fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
1067 _PATH_SSH_SYSTEM_RC);
1068 f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
1069 if (f) {
1070 if (do_xauth)
1071 fprintf(f, "%s %s\n", s->auth_proto,
1072 s->auth_data);
1073 pclose(f);
1074 } else
1075 fprintf(stderr, "Could not run %s\n",
1076 _PATH_SSH_SYSTEM_RC);
1077 } else if (do_xauth && options.xauth_location != NULL) {
1078 /* Add authority data to .Xauthority if appropriate. */
1079 if (debug_flag) {
1080 fprintf(stderr,
1081 "Running %.100s add "
1082 "%.100s %.100s %.100s\n",
1083 options.xauth_location, s->auth_display,
1084 s->auth_proto, s->auth_data);
1085 }
1086 snprintf(cmd, sizeof cmd, "%s -q -",
1087 options.xauth_location);
1088 f = popen(cmd, "w");
1089 if (f) {
1090 fprintf(f, "add %s %s %s\n",
1091 s->auth_display, s->auth_proto,
1092 s->auth_data);
1093 pclose(f);
1094 } else {
1095 fprintf(stderr, "Could not run %s\n",
1096 cmd);
1097 }
1098 }
1099}
1100
1101static void
1102do_nologin(struct passwd *pw)
1103{
1104 FILE *f = NULL;
1105 char buf[1024];
1106
1107#ifdef HAVE_LOGIN_CAP
1108 if (!login_getcapbool(lc, "ignorenologin", 0) && pw->pw_uid)
1109 f = fopen(login_getcapstr(lc, "nologin", _PATH_NOLOGIN,
1110 _PATH_NOLOGIN), "r");
1111#else
1112 if (pw->pw_uid)
1113 f = fopen(_PATH_NOLOGIN, "r");
1114#endif
1115 if (f) {
1116 /* /etc/nologin exists. Print its contents and exit. */
1117 while (fgets(buf, sizeof(buf), f))
1118 fputs(buf, stderr);
1119 fclose(f);
1120 exit(254);
1121 }
1122}
1123
1124/* Set login name, uid, gid, and groups. */
1125static void
1126do_setusercontext(struct passwd *pw)
1127{
1128#ifdef HAVE_CYGWIN
1129 if (is_winnt) {
1130#else /* HAVE_CYGWIN */
1131 if (getuid() == 0 || geteuid() == 0) {
1132#endif /* HAVE_CYGWIN */
1133#ifdef HAVE_GETUSERATTR
1134 set_limits_from_userattr(pw->pw_name);
1135#endif /* HAVE_GETUSERATTR */
1136#ifdef HAVE_LOGIN_CAP
1137 if (setusercontext(lc, pw, pw->pw_uid,
1138 (LOGIN_SETALL & ~LOGIN_SETPATH)) < 0) {
1139 perror("unable to set user context");
1140 exit(1);
1141 }
1142#else
1143# if defined(HAVE_GETLUID) && defined(HAVE_SETLUID)
1144 /* Sets login uid for accounting */
1145 if (getluid() == -1 && setluid(pw->pw_uid) == -1)
1146 error("setluid: %s", strerror(errno));
1147# endif /* defined(HAVE_GETLUID) && defined(HAVE_SETLUID) */
1148
1149 if (setlogin(pw->pw_name) < 0)
1150 error("setlogin failed: %s", strerror(errno));
1151 if (setgid(pw->pw_gid) < 0) {
1152 perror("setgid");
1153 exit(1);
1154 }
1155 /* Initialize the group list. */
1156 if (initgroups(pw->pw_name, pw->pw_gid) < 0) {
1157 perror("initgroups");
1158 exit(1);
1159 }
1160 endgrent();
1161# ifdef USE_PAM
1162 /*
1163 * PAM credentials may take the form of supplementary groups.
1164 * These will have been wiped by the above initgroups() call.
1165 * Reestablish them here.
1166 */
1167 do_pam_setcred(0);
1168# endif /* USE_PAM */
1169# if defined(WITH_IRIX_PROJECT) || defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY)
1170 irix_setusercontext(pw);
1171# endif /* defined(WITH_IRIX_PROJECT) || defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY) */
1172 /* Permanently switch to the desired uid. */
1173 permanently_set_uid(pw);
1174#endif
1175 }
1176 if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
1177 fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
1178}
1179
1180/*
1181 * Performs common processing for the child, such as setting up the
1182 * environment, closing extra file descriptors, setting the user and group
1183 * ids, and executing the command or shell.
1184 */
1185void
1186do_child(Session *s, const char *command)
1187{
1188 extern char **environ;
1189 char **env;
1190 char *argv[10];
1191 const char *shell, *shell0, *hostname = NULL;
1192 struct passwd *pw = s->pw;
1193 u_int i;
1194
1195 /* remove hostkey from the child's memory */
1196 destroy_sensitive_data();
1197
1198 /* login(1) is only called if we execute the login shell */
1199 if (options.use_login && command != NULL)
1200 options.use_login = 0;
1201
1202 /*
1203 * Login(1) does this as well, and it needs uid 0 for the "-h"
1204 * switch, so we let login(1) to this for us.
1205 */
1206 if (!options.use_login) {
1207#ifdef HAVE_OSF_SIA
1208 session_setup_sia(pw->pw_name, s->ttyfd == -1 ? NULL : s->tty);
1209 if (!check_quietlogin(s, command))
1210 do_motd();
1211#else /* HAVE_OSF_SIA */
1212 do_nologin(pw);
1213# ifdef _AIX
1214 aix_usrinfo(pw, s->tty, s->ttyfd);
1215# endif /* _AIX */
1216 do_setusercontext(pw);
1217#endif /* HAVE_OSF_SIA */
1218 }
1219
1220 /*
1221 * Get the shell from the password data. An empty shell field is
1222 * legal, and means /bin/sh.
1223 */
1224 shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1225#ifdef HAVE_LOGIN_CAP
1226 shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
1227#endif
1228
1229 env = do_setup_env(s, shell);
1230
3c0ef626 1231 /* we have to stash the hostname before we close our socket. */
1232 if (options.use_login)
1233 hostname = get_remote_name_or_ip(utmp_len,
e9702f7d 1234 options.verify_reverse_mapping);
3c0ef626 1235 /*
1236 * Close the connection descriptors; note that this is the child, and
1237 * the server will still have the socket open, and it is important
1238 * that we do not shutdown it. Note that the descriptors cannot be
1239 * closed before building the environment, as we call
1240 * get_remote_ipaddr there.
1241 */
1242 if (packet_get_connection_in() == packet_get_connection_out())
1243 close(packet_get_connection_in());
1244 else {
1245 close(packet_get_connection_in());
1246 close(packet_get_connection_out());
1247 }
1248 /*
1249 * Close all descriptors related to channels. They will still remain
1250 * open in the parent.
1251 */
1252 /* XXX better use close-on-exec? -markus */
1253 channel_close_all();
1254
1255 /*
1256 * Close any extra file descriptors. Note that there may still be
1257 * descriptors left by system functions. They will be closed later.
1258 */
1259 endpwent();
1260
1261 /*
1262 * Close any extra open file descriptors so that we don\'t have them
1263 * hanging around in clients. Note that we want to do this after
1264 * initgroups, because at least on Solaris 2.3 it leaves file
1265 * descriptors open.
1266 */
1267 for (i = 3; i < 64; i++)
1268 close(i);
1269
1270 /*
e9702f7d 1271 * Must take new environment into use so that .ssh/rc,
1272 * /etc/ssh/sshrc and xauth are run in the proper environment.
3c0ef626 1273 */
1274 environ = env;
1275
1276#ifdef AFS
1277 /* Try to get AFS tokens for the local cell. */
1278 if (k_hasafs()) {
1279 char cell[64];
e9702f7d 1280
3c0ef626 1281 if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
1282 krb_afslog(cell, 0);
e9702f7d 1283
3c0ef626 1284 krb_afslog(0, 0);
1285 }
1286#endif /* AFS */
1287
1288 /* Change current directory to the user\'s home directory. */
1289 if (chdir(pw->pw_dir) < 0) {
1290 fprintf(stderr, "Could not chdir to home directory %s: %s\n",
1291 pw->pw_dir, strerror(errno));
1292#ifdef HAVE_LOGIN_CAP
1293 if (login_getcapbool(lc, "requirehome", 0))
1294 exit(1);
1295#endif
1296 }
1297
e9702f7d 1298 if (!options.use_login)
1299 do_rc_files(s, shell);
3c0ef626 1300
1301 /* restore SIGPIPE for child */
1302 signal(SIGPIPE, SIG_DFL);
1303
e9702f7d 1304 if (options.use_login) {
1305 /* Launch login(1). */
1306
1307 execl(LOGIN_PROGRAM, "login", "-h", hostname,
1308#ifdef LOGIN_NEEDS_TERM
1309 (s->term ? s->term : "unknown"),
1310#endif /* LOGIN_NEEDS_TERM */
1311 "-p", "-f", "--", pw->pw_name, (char *)NULL);
1312
1313 /* Login couldn't be executed, die. */
1314
1315 perror("login");
1316 exit(1);
1317 }
1318
1319 /* Get the last component of the shell name. */
1320 if ((shell0 = strrchr(shell, '/')) != NULL)
1321 shell0++;
1322 else
1323 shell0 = shell;
1324
3c0ef626 1325 /*
1326 * If we have no command, execute the shell. In this case, the shell
1327 * name to be passed in argv[0] is preceded by '-' to indicate that
1328 * this is a login shell.
1329 */
1330 if (!command) {
e9702f7d 1331 char argv0[256];
3c0ef626 1332
e9702f7d 1333 /* Start the shell. Set initial character to '-'. */
1334 argv0[0] = '-';
3c0ef626 1335
e9702f7d 1336 if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1)
1337 >= sizeof(argv0) - 1) {
1338 errno = EINVAL;
3c0ef626 1339 perror(shell);
1340 exit(1);
e9702f7d 1341 }
3c0ef626 1342
e9702f7d 1343 /* Execute the shell. */
1344 argv[0] = argv0;
1345 argv[1] = NULL;
1346 execve(shell, argv, env);
3c0ef626 1347
e9702f7d 1348 /* Executing the shell failed. */
1349 perror(shell);
1350 exit(1);
3c0ef626 1351 }
1352 /*
1353 * Execute the command using the user's shell. This uses the -c
1354 * option to execute the command.
1355 */
e9702f7d 1356 argv[0] = (char *) shell0;
3c0ef626 1357 argv[1] = "-c";
1358 argv[2] = (char *) command;
1359 argv[3] = NULL;
1360 execve(shell, argv, env);
1361 perror(shell);
1362 exit(1);
1363}
1364
1365Session *
1366session_new(void)
1367{
1368 int i;
1369 static int did_init = 0;
1370 if (!did_init) {
1371 debug("session_new: init");
e9702f7d 1372 for (i = 0; i < MAX_SESSIONS; i++) {
3c0ef626 1373 sessions[i].used = 0;
1374 }
1375 did_init = 1;
1376 }
e9702f7d 1377 for (i = 0; i < MAX_SESSIONS; i++) {
3c0ef626 1378 Session *s = &sessions[i];
1379 if (! s->used) {
1380 memset(s, 0, sizeof(*s));
1381 s->chanid = -1;
1382 s->ptyfd = -1;
1383 s->ttyfd = -1;
1384 s->used = 1;
1385 s->self = i;
1386 debug("session_new: session %d", i);
1387 return s;
1388 }
1389 }
1390 return NULL;
1391}
1392
1393static void
1394session_dump(void)
1395{
1396 int i;
e9702f7d 1397 for (i = 0; i < MAX_SESSIONS; i++) {
3c0ef626 1398 Session *s = &sessions[i];
1399 debug("dump: used %d session %d %p channel %d pid %d",
1400 s->used,
1401 s->self,
1402 s,
1403 s->chanid,
1404 s->pid);
1405 }
1406}
1407
1408int
1409session_open(Authctxt *authctxt, int chanid)
1410{
1411 Session *s = session_new();
1412 debug("session_open: channel %d", chanid);
1413 if (s == NULL) {
1414 error("no more sessions");
1415 return 0;
1416 }
1417 s->authctxt = authctxt;
1418 s->pw = authctxt->pw;
1419 if (s->pw == NULL)
1420 fatal("no user for session %d", s->self);
1421 debug("session_open: session %d: link with channel %d", s->self, chanid);
1422 s->chanid = chanid;
1423 return 1;
1424}
1425
1426static Session *
1427session_by_channel(int id)
1428{
1429 int i;
e9702f7d 1430 for (i = 0; i < MAX_SESSIONS; i++) {
3c0ef626 1431 Session *s = &sessions[i];
1432 if (s->used && s->chanid == id) {
1433 debug("session_by_channel: session %d channel %d", i, id);
1434 return s;
1435 }
1436 }
1437 debug("session_by_channel: unknown channel %d", id);
1438 session_dump();
1439 return NULL;
1440}
1441
1442static Session *
1443session_by_pid(pid_t pid)
1444{
1445 int i;
1446 debug("session_by_pid: pid %d", pid);
e9702f7d 1447 for (i = 0; i < MAX_SESSIONS; i++) {
3c0ef626 1448 Session *s = &sessions[i];
1449 if (s->used && s->pid == pid)
1450 return s;
1451 }
1452 error("session_by_pid: unknown pid %d", pid);
1453 session_dump();
1454 return NULL;
1455}
1456
1457static int
1458session_window_change_req(Session *s)
1459{
1460 s->col = packet_get_int();
1461 s->row = packet_get_int();
1462 s->xpixel = packet_get_int();
1463 s->ypixel = packet_get_int();
e9702f7d 1464 packet_check_eom();
3c0ef626 1465 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1466 return 1;
1467}
1468
1469static int
1470session_pty_req(Session *s)
1471{
1472 u_int len;
1473 int n_bytes;
1474
1475 if (no_pty_flag) {
1476 debug("Allocating a pty not permitted for this authentication.");
1477 return 0;
1478 }
1479 if (s->ttyfd != -1) {
1480 packet_disconnect("Protocol error: you already have a pty.");
1481 return 0;
1482 }
1483
1484 s->term = packet_get_string(&len);
1485
1486 if (compat20) {
1487 s->col = packet_get_int();
1488 s->row = packet_get_int();
1489 } else {
1490 s->row = packet_get_int();
1491 s->col = packet_get_int();
1492 }
1493 s->xpixel = packet_get_int();
1494 s->ypixel = packet_get_int();
1495
1496 if (strcmp(s->term, "") == 0) {
1497 xfree(s->term);
1498 s->term = NULL;
1499 }
1500
1501 /* Allocate a pty and open it. */
1502 debug("Allocating pty.");
1503 if (!pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty))) {
1504 if (s->term)
1505 xfree(s->term);
1506 s->term = NULL;
1507 s->ptyfd = -1;
1508 s->ttyfd = -1;
1509 error("session_pty_req: session %d alloc failed", s->self);
1510 return 0;
1511 }
1512 debug("session_pty_req: session %d alloc %s", s->self, s->tty);
1513
1514 /* for SSH1 the tty modes length is not given */
1515 if (!compat20)
1516 n_bytes = packet_remaining();
1517 tty_parse_modes(s->ttyfd, &n_bytes);
1518
1519 /*
1520 * Add a cleanup function to clear the utmp entry and record logout
1521 * time in case we call fatal() (e.g., the connection gets closed).
1522 */
1523 fatal_add_cleanup(session_pty_cleanup, (void *)s);
1524 pty_setowner(s->pw, s->tty);
1525
1526 /* Set window size from the packet. */
1527 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1528
e9702f7d 1529 packet_check_eom();
3c0ef626 1530 session_proctitle(s);
1531 return 1;
1532}
1533
1534static int
1535session_subsystem_req(Session *s)
1536{
1537 struct stat st;
1538 u_int len;
1539 int success = 0;
1540 char *cmd, *subsys = packet_get_string(&len);
1541 int i;
1542
e9702f7d 1543 packet_check_eom();
1544 log("subsystem request for %.100s", subsys);
3c0ef626 1545
1546 for (i = 0; i < options.num_subsystems; i++) {
1547 if (strcmp(subsys, options.subsystem_name[i]) == 0) {
1548 cmd = options.subsystem_command[i];
1549 if (stat(cmd, &st) < 0) {
1550 error("subsystem: cannot stat %s: %s", cmd,
1551 strerror(errno));
1552 break;
1553 }
1554 debug("subsystem: exec() %s", cmd);
1555 s->is_subsystem = 1;
1556 do_exec(s, cmd);
1557 success = 1;
e9702f7d 1558 break;
3c0ef626 1559 }
1560 }
1561
1562 if (!success)
e9702f7d 1563 log("subsystem request for %.100s failed, subsystem not found",
3c0ef626 1564 subsys);
1565
1566 xfree(subsys);
1567 return success;
1568}
1569
1570static int
1571session_x11_req(Session *s)
1572{
1573 int success;
1574
1575 s->single_connection = packet_get_char();
1576 s->auth_proto = packet_get_string(NULL);
1577 s->auth_data = packet_get_string(NULL);
1578 s->screen = packet_get_int();
e9702f7d 1579 packet_check_eom();
3c0ef626 1580
1581 success = session_setup_x11fwd(s);
1582 if (!success) {
1583 xfree(s->auth_proto);
1584 xfree(s->auth_data);
1585 s->auth_proto = NULL;
1586 s->auth_data = NULL;
1587 }
1588 return success;
1589}
1590
1591static int
1592session_shell_req(Session *s)
1593{
e9702f7d 1594 packet_check_eom();
3c0ef626 1595 do_exec(s, NULL);
1596 return 1;
1597}
1598
1599static int
1600session_exec_req(Session *s)
1601{
1602 u_int len;
1603 char *command = packet_get_string(&len);
e9702f7d 1604 packet_check_eom();
3c0ef626 1605 do_exec(s, command);
1606 xfree(command);
1607 return 1;
1608}
1609
1610static int
1611session_auth_agent_req(Session *s)
1612{
1613 static int called = 0;
e9702f7d 1614 packet_check_eom();
3c0ef626 1615 if (no_agent_forwarding_flag) {
1616 debug("session_auth_agent_req: no_agent_forwarding_flag");
1617 return 0;
1618 }
1619 if (called) {
1620 return 0;
1621 } else {
1622 called = 1;
1623 return auth_input_request_forwarding(s->pw);
1624 }
1625}
1626
e9702f7d 1627int
1628session_input_channel_req(Channel *c, const char *rtype)
3c0ef626 1629{
3c0ef626 1630 int success = 0;
3c0ef626 1631 Session *s;
3c0ef626 1632
e9702f7d 1633 if ((s = session_by_channel(c->self)) == NULL) {
1634 log("session_input_channel_req: no session %d req %.100s",
1635 c->self, rtype);
1636 return 0;
1637 }
1638 debug("session_input_channel_req: session %d req %s", s->self, rtype);
3c0ef626 1639
1640 /*
1641 * a session is in LARVAL state until a shell, a command
1642 * or a subsystem is executed
1643 */
1644 if (c->type == SSH_CHANNEL_LARVAL) {
1645 if (strcmp(rtype, "shell") == 0) {
1646 success = session_shell_req(s);
1647 } else if (strcmp(rtype, "exec") == 0) {
1648 success = session_exec_req(s);
1649 } else if (strcmp(rtype, "pty-req") == 0) {
1650 success = session_pty_req(s);
1651 } else if (strcmp(rtype, "x11-req") == 0) {
1652 success = session_x11_req(s);
1653 } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
1654 success = session_auth_agent_req(s);
1655 } else if (strcmp(rtype, "subsystem") == 0) {
1656 success = session_subsystem_req(s);
1657 }
1658 }
1659 if (strcmp(rtype, "window-change") == 0) {
1660 success = session_window_change_req(s);
1661 }
e9702f7d 1662 return success;
3c0ef626 1663}
1664
1665void
1666session_set_fds(Session *s, int fdin, int fdout, int fderr)
1667{
1668 if (!compat20)
1669 fatal("session_set_fds: called for proto != 2.0");
1670 /*
1671 * now that have a child and a pipe to the child,
1672 * we can activate our channel and register the fd's
1673 */
1674 if (s->chanid == -1)
1675 fatal("no channel for session %d", s->self);
1676 channel_set_fds(s->chanid,
1677 fdout, fdin, fderr,
1678 fderr == -1 ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
e9702f7d 1679 1,
1680 CHAN_SES_WINDOW_DEFAULT);
3c0ef626 1681}
1682
1683/*
1684 * Function to perform pty cleanup. Also called if we get aborted abnormally
1685 * (e.g., due to a dropped connection).
1686 */
1687static void
1688session_pty_cleanup(void *session)
1689{
1690 Session *s = session;
1691
1692 if (s == NULL) {
1693 error("session_pty_cleanup: no session");
1694 return;
1695 }
1696 if (s->ttyfd == -1)
1697 return;
1698
1699 debug("session_pty_cleanup: session %d release %s", s->self, s->tty);
1700
1701 /* Record that the user has logged out. */
1702 if (s->pid != 0)
e9702f7d 1703 record_logout(s->pid, s->tty, s->pw->pw_name);
3c0ef626 1704
1705 /* Release the pseudo-tty. */
1706 pty_release(s->tty);
1707
1708 /*
1709 * Close the server side of the socket pairs. We must do this after
1710 * the pty cleanup, so that another process doesn't get this pty
1711 * while we're still cleaning up.
1712 */
1713 if (close(s->ptymaster) < 0)
1714 error("close(s->ptymaster): %s", strerror(errno));
1715
1716 /* unlink pty from session */
1717 s->ttyfd = -1;
1718}
1719
1720static void
1721session_exit_message(Session *s, int status)
1722{
1723 Channel *c;
e9702f7d 1724
1725 if ((c = channel_lookup(s->chanid)) == NULL)
3c0ef626 1726 fatal("session_exit_message: session %d: no channel %d",
1727 s->self, s->chanid);
1728 debug("session_exit_message: session %d channel %d pid %d",
1729 s->self, s->chanid, s->pid);
1730
1731 if (WIFEXITED(status)) {
e9702f7d 1732 channel_request_start(s->chanid, "exit-status", 0);
3c0ef626 1733 packet_put_int(WEXITSTATUS(status));
1734 packet_send();
1735 } else if (WIFSIGNALED(status)) {
e9702f7d 1736 channel_request_start(s->chanid, "exit-signal", 0);
3c0ef626 1737 packet_put_int(WTERMSIG(status));
1738#ifdef WCOREDUMP
1739 packet_put_char(WCOREDUMP(status));
1740#else /* WCOREDUMP */
1741 packet_put_char(0);
1742#endif /* WCOREDUMP */
1743 packet_put_cstring("");
1744 packet_put_cstring("");
1745 packet_send();
1746 } else {
1747 /* Some weird exit cause. Just exit. */
1748 packet_disconnect("wait returned status %04x.", status);
1749 }
1750
1751 /* disconnect channel */
1752 debug("session_exit_message: release channel %d", s->chanid);
1753 channel_cancel_cleanup(s->chanid);
1754 /*
1755 * emulate a write failure with 'chan_write_failed', nobody will be
1756 * interested in data we write.
1757 * Note that we must not call 'chan_read_failed', since there could
1758 * be some more data waiting in the pipe.
1759 */
1760 if (c->ostate != CHAN_OUTPUT_CLOSED)
1761 chan_write_failed(c);
1762 s->chanid = -1;
1763}
1764
1765static void
1766session_close(Session *s)
1767{
1768 debug("session_close: session %d pid %d", s->self, s->pid);
1769 if (s->ttyfd != -1) {
1770 fatal_remove_cleanup(session_pty_cleanup, (void *)s);
1771 session_pty_cleanup(s);
1772 }
1773 if (s->term)
1774 xfree(s->term);
1775 if (s->display)
1776 xfree(s->display);
e9702f7d 1777 if (s->auth_display)
1778 xfree(s->auth_display);
3c0ef626 1779 if (s->auth_data)
1780 xfree(s->auth_data);
1781 if (s->auth_proto)
1782 xfree(s->auth_proto);
1783 s->used = 0;
1784 session_proctitle(s);
1785}
1786
1787void
1788session_close_by_pid(pid_t pid, int status)
1789{
1790 Session *s = session_by_pid(pid);
1791 if (s == NULL) {
1792 debug("session_close_by_pid: no session for pid %d", pid);
1793 return;
1794 }
1795 if (s->chanid != -1)
1796 session_exit_message(s, status);
1797 session_close(s);
1798}
1799
1800/*
1801 * this is called when a channel dies before
1802 * the session 'child' itself dies
1803 */
1804void
1805session_close_by_channel(int id, void *arg)
1806{
1807 Session *s = session_by_channel(id);
1808 if (s == NULL) {
1809 debug("session_close_by_channel: no session for id %d", id);
1810 return;
1811 }
1812 debug("session_close_by_channel: channel %d child %d", id, s->pid);
1813 if (s->pid != 0) {
1814 debug("session_close_by_channel: channel %d: has child", id);
1815 /*
1816 * delay detach of session, but release pty, since
1817 * the fd's to the child are already closed
1818 */
1819 if (s->ttyfd != -1) {
1820 fatal_remove_cleanup(session_pty_cleanup, (void *)s);
1821 session_pty_cleanup(s);
1822 }
1823 return;
1824 }
1825 /* detach by removing callback */
1826 channel_cancel_cleanup(s->chanid);
1827 s->chanid = -1;
1828 session_close(s);
1829}
1830
1831void
1832session_destroy_all(void)
1833{
1834 int i;
e9702f7d 1835 for (i = 0; i < MAX_SESSIONS; i++) {
3c0ef626 1836 Session *s = &sessions[i];
e9702f7d 1837 if (s->used)
3c0ef626 1838 session_close(s);
1839 }
1840}
1841
1842static char *
1843session_tty_list(void)
1844{
1845 static char buf[1024];
1846 int i;
1847 buf[0] = '\0';
e9702f7d 1848 for (i = 0; i < MAX_SESSIONS; i++) {
3c0ef626 1849 Session *s = &sessions[i];
1850 if (s->used && s->ttyfd != -1) {
1851 if (buf[0] != '\0')
1852 strlcat(buf, ",", sizeof buf);
1853 strlcat(buf, strrchr(s->tty, '/') + 1, sizeof buf);
1854 }
1855 }
1856 if (buf[0] == '\0')
1857 strlcpy(buf, "notty", sizeof buf);
1858 return buf;
1859}
1860
1861void
1862session_proctitle(Session *s)
1863{
1864 if (s->pw == NULL)
1865 error("no user for session %d", s->self);
1866 else
1867 setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
1868}
1869
1870int
1871session_setup_x11fwd(Session *s)
1872{
1873 struct stat st;
e9702f7d 1874 char display[512], auth_display[512];
1875 char hostname[MAXHOSTNAMELEN];
3c0ef626 1876
1877 if (no_x11_forwarding_flag) {
1878 packet_send_debug("X11 forwarding disabled in user configuration file.");
1879 return 0;
1880 }
1881 if (!options.x11_forwarding) {
1882 debug("X11 forwarding disabled in server configuration file.");
1883 return 0;
1884 }
1885 if (!options.xauth_location ||
1886 (stat(options.xauth_location, &st) == -1)) {
1887 packet_send_debug("No xauth program; cannot forward with spoofing.");
1888 return 0;
1889 }
1890 if (options.use_login) {
1891 packet_send_debug("X11 forwarding disabled; "
1892 "not compatible with UseLogin=yes.");
1893 return 0;
1894 }
1895 if (s->display != NULL) {
1896 debug("X11 display already set.");
1897 return 0;
1898 }
e9702f7d 1899 s->display_number = x11_create_display_inet(options.x11_display_offset,
1900 options.x11_use_localhost, s->single_connection);
1901 if (s->display_number == -1) {
3c0ef626 1902 debug("x11_create_display_inet failed.");
1903 return 0;
1904 }
e9702f7d 1905
1906 /* Set up a suitable value for the DISPLAY variable. */
1907 if (gethostname(hostname, sizeof(hostname)) < 0)
1908 fatal("gethostname: %.100s", strerror(errno));
1909 /*
1910 * auth_display must be used as the displayname when the
1911 * authorization entry is added with xauth(1). This will be
1912 * different than the DISPLAY string for localhost displays.
1913 */
1914 if (options.x11_use_localhost) {
1915 snprintf(display, sizeof display, "localhost:%d.%d",
1916 s->display_number, s->screen);
1917 snprintf(auth_display, sizeof auth_display, "unix:%d.%d",
1918 s->display_number, s->screen);
1919 s->display = xstrdup(display);
1920 s->auth_display = xstrdup(auth_display);
1921 } else {
1922#ifdef IPADDR_IN_DISPLAY
1923 struct hostent *he;
1924 struct in_addr my_addr;
1925
1926 he = gethostbyname(hostname);
1927 if (he == NULL) {
1928 error("Can't get IP address for X11 DISPLAY.");
1929 packet_send_debug("Can't get IP address for X11 DISPLAY.");
1930 return 0;
1931 }
1932 memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr));
1933 snprintf(display, sizeof display, "%.50s:%d.%d", inet_ntoa(my_addr),
1934 s->display_number, s->screen);
1935#else
1936 snprintf(display, sizeof display, "%.400s:%d.%d", hostname,
1937 s->display_number, s->screen);
1938#endif
1939 s->display = xstrdup(display);
1940 s->auth_display = xstrdup(display);
1941 }
1942
3c0ef626 1943 return 1;
1944}
1945
1946static void
1947do_authenticated2(Authctxt *authctxt)
1948{
1949 server_loop2(authctxt);
5598e598 1950#if defined(GSSAPI)
1951 ssh_gssapi_cleanup_creds(NULL);
1952#endif
3c0ef626 1953}
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