Raise WARNS in secure/ as high as possible and fix some resulting warnings.
[dragonfly.git] / crypto / openssh / session.c
CommitLineData
40c002af 1/* $OpenBSD: session.c,v 1.246 2009/04/17 19:23:06 stevesk Exp $ */
16c343f1
PA
2/*
3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
4 * All rights reserved
5 *
6 * As far as I am concerned, the code I have written for this software
7 * can be used freely for any purpose. Any derived versions of this
8 * software must be clearly marked as such, and if the derived work is
9 * incompatible with the protocol description in the RFC file, it must be
10 * called by a name other than "ssh" or "Secure Shell".
11 *
12 * SSH2 support by Markus Friedl.
13 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
14 *
15 * Redistribution and use in source and binary forms, with or without
16 * modification, are permitted provided that the following conditions
17 * are met:
18 * 1. Redistributions of source code must retain the above copyright
19 * notice, this list of conditions and the following disclaimer.
20 * 2. Redistributions in binary form must reproduce the above copyright
21 * notice, this list of conditions and the following disclaimer in the
22 * documentation and/or other materials provided with the distribution.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
25 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
26 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
27 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
28 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
29 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
30 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
31 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
32 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
33 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
34 */
35
36#include "includes.h"
37
38#include <sys/types.h>
39#include <sys/param.h>
40#ifdef HAVE_SYS_STAT_H
41# include <sys/stat.h>
42#endif
43#include <sys/socket.h>
44#include <sys/un.h>
45#include <sys/wait.h>
46
47#include <arpa/inet.h>
48
49#include <errno.h>
50#include <grp.h>
51#ifdef HAVE_PATHS_H
52#include <paths.h>
53#endif
54#include <pwd.h>
55#include <signal.h>
56#include <stdarg.h>
57#include <stdio.h>
58#include <stdlib.h>
59#include <string.h>
60#include <unistd.h>
61
c8c467ee 62#include "openbsd-compat/sys-queue.h"
16c343f1
PA
63#include "xmalloc.h"
64#include "ssh.h"
65#include "ssh1.h"
66#include "ssh2.h"
67#include "sshpty.h"
68#include "packet.h"
69#include "buffer.h"
70#include "match.h"
71#include "uidswap.h"
72#include "compat.h"
73#include "channels.h"
74#include "key.h"
75#include "cipher.h"
76#ifdef GSSAPI
77#include "ssh-gss.h"
78#endif
79#include "hostfile.h"
80#include "auth.h"
81#include "auth-options.h"
82#include "pathnames.h"
83#include "log.h"
84#include "servconf.h"
85#include "sshlogin.h"
86#include "serverloop.h"
87#include "canohost.h"
88#include "misc.h"
89#include "session.h"
90#include "kex.h"
91#include "monitor_wrap.h"
92#include "sftp.h"
93
94#if defined(KRB5) && defined(USE_AFS)
95#include <kafs.h>
96#endif
97
cb5eb4f1
PA
98#define IS_INTERNAL_SFTP(c) \
99 (!strncmp(c, INTERNAL_SFTP_NAME, sizeof(INTERNAL_SFTP_NAME) - 1) && \
100 (c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\0' || \
101 c[sizeof(INTERNAL_SFTP_NAME) - 1] == ' ' || \
102 c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\t'))
103
16c343f1
PA
104/* func */
105
106Session *session_new(void);
c8c467ee 107void session_set_fds(Session *, int, int, int, int);
16c343f1
PA
108void session_pty_cleanup(Session *);
109void session_proctitle(Session *);
110int session_setup_x11fwd(Session *);
c8c467ee
PA
111int do_exec_pty(Session *, const char *);
112int do_exec_no_pty(Session *, const char *);
113int do_exec(Session *, const char *);
16c343f1
PA
114void do_login(Session *, const char *);
115#ifdef LOGIN_NEEDS_UTMPX
116static void do_pre_login(Session *s);
117#endif
118void do_child(Session *, const char *);
119void do_motd(void);
120int check_quietlogin(Session *, const char *);
121
122static void do_authenticated1(Authctxt *);
123static void do_authenticated2(Authctxt *);
124
125static int session_pty_req(Session *);
126
127/* import */
128extern ServerOptions options;
129extern char *__progname;
130extern int log_stderr;
131extern int debug_flag;
132extern u_int utmp_len;
133extern int startup_pipe;
134extern void destroy_sensitive_data(void);
135extern Buffer loginmsg;
136
137/* original command from peer. */
138const char *original_command = NULL;
139
140/* data */
c8c467ee
PA
141static int sessions_first_unused = -1;
142static int sessions_nalloc = 0;
143static Session *sessions = NULL;
16c343f1
PA
144
145#define SUBSYSTEM_NONE 0
146#define SUBSYSTEM_EXT 1
147#define SUBSYSTEM_INT_SFTP 2
148
149#ifdef HAVE_LOGIN_CAP
150login_cap_t *lc;
151#endif
152
153static int is_child = 0;
154
155/* Name and directory of socket for authentication agent forwarding. */
156static char *auth_sock_name = NULL;
157static char *auth_sock_dir = NULL;
158
159/* removes the agent forwarding socket */
160
161static void
162auth_sock_cleanup_proc(struct passwd *pw)
163{
164 if (auth_sock_name != NULL) {
165 temporarily_use_uid(pw);
166 unlink(auth_sock_name);
167 rmdir(auth_sock_dir);
168 auth_sock_name = NULL;
169 restore_uid();
170 }
171}
172
173static int
174auth_input_request_forwarding(struct passwd * pw)
175{
176 Channel *nc;
c8c467ee 177 int sock = -1;
16c343f1
PA
178 struct sockaddr_un sunaddr;
179
180 if (auth_sock_name != NULL) {
181 error("authentication forwarding requested twice.");
182 return 0;
183 }
184
185 /* Temporarily drop privileged uid for mkdir/bind. */
186 temporarily_use_uid(pw);
187
188 /* Allocate a buffer for the socket name, and format the name. */
c8c467ee 189 auth_sock_dir = xstrdup("/tmp/ssh-XXXXXXXXXX");
16c343f1
PA
190
191 /* Create private directory for socket */
192 if (mkdtemp(auth_sock_dir) == NULL) {
193 packet_send_debug("Agent forwarding disabled: "
194 "mkdtemp() failed: %.100s", strerror(errno));
195 restore_uid();
16c343f1 196 xfree(auth_sock_dir);
16c343f1 197 auth_sock_dir = NULL;
c8c467ee 198 goto authsock_err;
16c343f1 199 }
c8c467ee
PA
200
201 xasprintf(&auth_sock_name, "%s/agent.%ld",
202 auth_sock_dir, (long) getpid());
16c343f1
PA
203
204 /* Create the socket. */
205 sock = socket(AF_UNIX, SOCK_STREAM, 0);
c8c467ee
PA
206 if (sock < 0) {
207 error("socket: %.100s", strerror(errno));
208 restore_uid();
209 goto authsock_err;
210 }
16c343f1
PA
211
212 /* Bind it to the name. */
213 memset(&sunaddr, 0, sizeof(sunaddr));
214 sunaddr.sun_family = AF_UNIX;
215 strlcpy(sunaddr.sun_path, auth_sock_name, sizeof(sunaddr.sun_path));
216
c8c467ee
PA
217 if (bind(sock, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) < 0) {
218 error("bind: %.100s", strerror(errno));
219 restore_uid();
220 goto authsock_err;
221 }
16c343f1
PA
222
223 /* Restore the privileged uid. */
224 restore_uid();
225
226 /* Start listening on the socket. */
c8c467ee
PA
227 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
228 error("listen: %.100s", strerror(errno));
229 goto authsock_err;
230 }
16c343f1
PA
231
232 /* Allocate a channel for the authentication agent socket. */
c29cd1cc 233 /* this shouldn't matter if its hpn or not - cjr */
16c343f1
PA
234 nc = channel_new("auth socket",
235 SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1,
236 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
237 0, "auth socket", 1);
cb5eb4f1 238 nc->path = xstrdup(auth_sock_name);
16c343f1 239 return 1;
c8c467ee
PA
240
241 authsock_err:
242 if (auth_sock_name != NULL)
243 xfree(auth_sock_name);
244 if (auth_sock_dir != NULL) {
245 rmdir(auth_sock_dir);
246 xfree(auth_sock_dir);
247 }
248 if (sock != -1)
249 close(sock);
250 auth_sock_name = NULL;
251 auth_sock_dir = NULL;
252 return 0;
16c343f1
PA
253}
254
255static void
256display_loginmsg(void)
257{
258 if (buffer_len(&loginmsg) > 0) {
259 buffer_append(&loginmsg, "\0", 1);
260 printf("%s", (char *)buffer_ptr(&loginmsg));
261 buffer_clear(&loginmsg);
262 }
263}
264
265void
266do_authenticated(Authctxt *authctxt)
267{
268 setproctitle("%s", authctxt->pw->pw_name);
269
270 /* setup the channel layer */
271 if (!no_port_forwarding_flag && options.allow_tcp_forwarding)
272 channel_permit_all_opens();
273
274 if (compat20)
275 do_authenticated2(authctxt);
276 else
277 do_authenticated1(authctxt);
278
279 do_cleanup(authctxt);
280}
281
282/*
283 * Prepares for an interactive session. This is called after the user has
284 * been successfully authenticated. During this message exchange, pseudo
285 * terminals are allocated, X11, TCP/IP, and authentication agent forwardings
286 * are requested, etc.
287 */
288static void
289do_authenticated1(Authctxt *authctxt)
290{
291 Session *s;
292 char *command;
293 int success, type, screen_flag;
294 int enable_compression_after_reply = 0;
295 u_int proto_len, data_len, dlen, compression_level = 0;
296
297 s = session_new();
298 if (s == NULL) {
299 error("no more sessions");
300 return;
301 }
302 s->authctxt = authctxt;
303 s->pw = authctxt->pw;
304
305 /*
306 * We stay in this loop until the client requests to execute a shell
307 * or a command.
308 */
309 for (;;) {
310 success = 0;
311
312 /* Get a packet from the client. */
313 type = packet_read();
314
315 /* Process the packet. */
316 switch (type) {
317 case SSH_CMSG_REQUEST_COMPRESSION:
318 compression_level = packet_get_int();
319 packet_check_eom();
320 if (compression_level < 1 || compression_level > 9) {
321 packet_send_debug("Received invalid compression level %d.",
322 compression_level);
323 break;
324 }
325 if (options.compression == COMP_NONE) {
326 debug2("compression disabled");
327 break;
328 }
329 /* Enable compression after we have responded with SUCCESS. */
330 enable_compression_after_reply = 1;
331 success = 1;
332 break;
333
334 case SSH_CMSG_REQUEST_PTY:
335 success = session_pty_req(s);
336 break;
337
338 case SSH_CMSG_X11_REQUEST_FORWARDING:
339 s->auth_proto = packet_get_string(&proto_len);
340 s->auth_data = packet_get_string(&data_len);
341
342 screen_flag = packet_get_protocol_flags() &
343 SSH_PROTOFLAG_SCREEN_NUMBER;
344 debug2("SSH_PROTOFLAG_SCREEN_NUMBER: %d", screen_flag);
345
346 if (packet_remaining() == 4) {
347 if (!screen_flag)
348 debug2("Buggy client: "
349 "X11 screen flag missing");
350 s->screen = packet_get_int();
351 } else {
352 s->screen = 0;
353 }
354 packet_check_eom();
355 success = session_setup_x11fwd(s);
356 if (!success) {
357 xfree(s->auth_proto);
358 xfree(s->auth_data);
359 s->auth_proto = NULL;
360 s->auth_data = NULL;
361 }
362 break;
363
364 case SSH_CMSG_AGENT_REQUEST_FORWARDING:
c8c467ee
PA
365 if (!options.allow_agent_forwarding ||
366 no_agent_forwarding_flag || compat13) {
16c343f1
PA
367 debug("Authentication agent forwarding not permitted for this authentication.");
368 break;
369 }
370 debug("Received authentication agent forwarding request.");
371 success = auth_input_request_forwarding(s->pw);
372 break;
373
374 case SSH_CMSG_PORT_FORWARD_REQUEST:
375 if (no_port_forwarding_flag) {
376 debug("Port forwarding not permitted for this authentication.");
377 break;
378 }
379 if (!options.allow_tcp_forwarding) {
380 debug("Port forwarding not permitted.");
381 break;
382 }
383 debug("Received TCP/IP port forwarding request.");
384 if (channel_input_port_forward_request(s->pw->pw_uid == 0,
385 options.gateway_ports) < 0) {
386 debug("Port forwarding failed.");
387 break;
388 }
389 success = 1;
390 break;
391
392 case SSH_CMSG_MAX_PACKET_SIZE:
393 if (packet_set_maxsize(packet_get_int()) > 0)
394 success = 1;
395 break;
396
397 case SSH_CMSG_EXEC_SHELL:
398 case SSH_CMSG_EXEC_CMD:
399 if (type == SSH_CMSG_EXEC_CMD) {
400 command = packet_get_string(&dlen);
401 debug("Exec command '%.500s'", command);
c8c467ee
PA
402 if (do_exec(s, command) != 0)
403 packet_disconnect(
404 "command execution failed");
16c343f1
PA
405 xfree(command);
406 } else {
c8c467ee
PA
407 if (do_exec(s, NULL) != 0)
408 packet_disconnect(
409 "shell execution failed");
16c343f1
PA
410 }
411 packet_check_eom();
412 session_close(s);
413 return;
414
415 default:
416 /*
417 * Any unknown messages in this phase are ignored,
418 * and a failure message is returned.
419 */
420 logit("Unknown packet type received after authentication: %d", type);
421 }
422 packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE);
423 packet_send();
424 packet_write_wait();
425
426 /* Enable compression now that we have replied if appropriate. */
427 if (enable_compression_after_reply) {
428 enable_compression_after_reply = 0;
429 packet_start_compression(compression_level);
430 }
431 }
432}
433
c8c467ee 434#define USE_PIPES
16c343f1
PA
435/*
436 * This is called to fork and execute a command when we have no tty. This
437 * will call do_child from the child, and server_loop from the parent after
438 * setting up file descriptors and such.
439 */
c8c467ee 440int
16c343f1
PA
441do_exec_no_pty(Session *s, const char *command)
442{
443 pid_t pid;
444
445#ifdef USE_PIPES
446 int pin[2], pout[2], perr[2];
c8c467ee 447
16c343f1 448 /* Allocate pipes for communicating with the program. */
c8c467ee
PA
449 if (pipe(pin) < 0) {
450 error("%s: pipe in: %.100s", __func__, strerror(errno));
451 return -1;
452 }
453 if (pipe(pout) < 0) {
454 error("%s: pipe out: %.100s", __func__, strerror(errno));
455 close(pin[0]);
456 close(pin[1]);
457 return -1;
458 }
459 if (pipe(perr) < 0) {
460 error("%s: pipe err: %.100s", __func__, strerror(errno));
461 close(pin[0]);
462 close(pin[1]);
463 close(pout[0]);
464 close(pout[1]);
465 return -1;
466 }
467#else
16c343f1 468 int inout[2], err[2];
c8c467ee 469
16c343f1 470 /* Uses socket pairs to communicate with the program. */
c8c467ee
PA
471 if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0) {
472 error("%s: socketpair #1: %.100s", __func__, strerror(errno));
473 return -1;
474 }
475 if (socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0) {
476 error("%s: socketpair #2: %.100s", __func__, strerror(errno));
477 close(inout[0]);
478 close(inout[1]);
479 return -1;
480 }
481#endif
482
16c343f1
PA
483 if (s == NULL)
484 fatal("do_exec_no_pty: no session");
485
486 session_proctitle(s);
487
488 /* Fork the child. */
c8c467ee
PA
489 switch ((pid = fork())) {
490 case -1:
491 error("%s: fork: %.100s", __func__, strerror(errno));
492#ifdef USE_PIPES
493 close(pin[0]);
494 close(pin[1]);
495 close(pout[0]);
496 close(pout[1]);
497 close(perr[0]);
498 close(perr[1]);
499#else
500 close(inout[0]);
501 close(inout[1]);
502 close(err[0]);
503 close(err[1]);
504#endif
505 return -1;
506 case 0:
16c343f1
PA
507 is_child = 1;
508
509 /* Child. Reinitialize the log since the pid has changed. */
c8c467ee
PA
510 log_init(__progname, options.log_level,
511 options.log_facility, log_stderr);
16c343f1
PA
512
513 /*
514 * Create a new session and process group since the 4.4BSD
515 * setlogin() affects the entire process group.
516 */
517 if (setsid() < 0)
518 error("setsid failed: %.100s", strerror(errno));
519
520#ifdef USE_PIPES
521 /*
522 * Redirect stdin. We close the parent side of the socket
523 * pair, and make the child side the standard input.
524 */
525 close(pin[1]);
526 if (dup2(pin[0], 0) < 0)
527 perror("dup2 stdin");
528 close(pin[0]);
529
530 /* Redirect stdout. */
531 close(pout[0]);
532 if (dup2(pout[1], 1) < 0)
533 perror("dup2 stdout");
534 close(pout[1]);
535
536 /* Redirect stderr. */
537 close(perr[0]);
538 if (dup2(perr[1], 2) < 0)
539 perror("dup2 stderr");
540 close(perr[1]);
c8c467ee 541#else
16c343f1
PA
542 /*
543 * Redirect stdin, stdout, and stderr. Stdin and stdout will
544 * use the same socket, as some programs (particularly rdist)
545 * seem to depend on it.
546 */
547 close(inout[1]);
548 close(err[1]);
549 if (dup2(inout[0], 0) < 0) /* stdin */
550 perror("dup2 stdin");
c8c467ee 551 if (dup2(inout[0], 1) < 0) /* stdout (same as stdin) */
16c343f1 552 perror("dup2 stdout");
c8c467ee 553 close(inout[0]);
16c343f1
PA
554 if (dup2(err[0], 2) < 0) /* stderr */
555 perror("dup2 stderr");
c8c467ee
PA
556 close(err[0]);
557#endif
558
16c343f1
PA
559
560#ifdef _UNICOS
561 cray_init_job(s->pw); /* set up cray jid and tmpdir */
562#endif
563
564 /* Do processing for the child (exec command etc). */
565 do_child(s, command);
566 /* NOTREACHED */
c8c467ee
PA
567 default:
568 break;
16c343f1 569 }
c8c467ee 570
16c343f1
PA
571#ifdef _UNICOS
572 signal(WJSIGNAL, cray_job_termination_handler);
573#endif /* _UNICOS */
574#ifdef HAVE_CYGWIN
40c002af 575 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
16c343f1 576#endif
c8c467ee 577
16c343f1
PA
578 s->pid = pid;
579 /* Set interactive/non-interactive mode. */
580 packet_set_interactive(s->display != NULL);
c8c467ee
PA
581
582 /*
583 * Clear loginmsg, since it's the child's responsibility to display
584 * it to the user, otherwise multiple sessions may accumulate
585 * multiple copies of the login messages.
586 */
587 buffer_clear(&loginmsg);
588
16c343f1
PA
589#ifdef USE_PIPES
590 /* We are the parent. Close the child sides of the pipes. */
591 close(pin[0]);
592 close(pout[1]);
593 close(perr[1]);
594
595 if (compat20) {
596 if (s->is_subsystem) {
597 close(perr[0]);
598 perr[0] = -1;
599 }
c8c467ee 600 session_set_fds(s, pin[1], pout[0], perr[0], 0);
16c343f1
PA
601 } else {
602 /* Enter the interactive session. */
603 server_loop(pid, pin[1], pout[0], perr[0]);
604 /* server_loop has closed pin[1], pout[0], and perr[0]. */
605 }
c8c467ee 606#else
16c343f1
PA
607 /* We are the parent. Close the child sides of the socket pairs. */
608 close(inout[0]);
609 close(err[0]);
610
16c343f1
PA
611 /*
612 * Enter the interactive session. Note: server_loop must be able to
613 * handle the case that fdin and fdout are the same.
614 */
615 if (compat20) {
c8c467ee
PA
616 session_set_fds(s, inout[1], inout[1],
617 s->is_subsystem ? -1 : err[1], 0);
618 if (s->is_subsystem)
619 close(err[1]);
16c343f1
PA
620 } else {
621 server_loop(pid, inout[1], inout[1], err[1]);
622 /* server_loop has closed inout[1] and err[1]. */
623 }
c8c467ee
PA
624#endif
625 return 0;
16c343f1
PA
626}
627
628/*
629 * This is called to fork and execute a command when we have a tty. This
630 * will call do_child from the child, and server_loop from the parent after
631 * setting up file descriptors, controlling tty, updating wtmp, utmp,
632 * lastlog, and other such operations.
633 */
c8c467ee 634int
16c343f1
PA
635do_exec_pty(Session *s, const char *command)
636{
637 int fdout, ptyfd, ttyfd, ptymaster;
638 pid_t pid;
639
640 if (s == NULL)
641 fatal("do_exec_pty: no session");
642 ptyfd = s->ptyfd;
643 ttyfd = s->ttyfd;
644
c8c467ee
PA
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 * Do this before forking (and cleanup in the child) so as to
650 * detect and gracefully fail out-of-fd conditions.
651 */
652 if ((fdout = dup(ptyfd)) < 0) {
653 error("%s: dup #1: %s", __func__, strerror(errno));
654 close(ttyfd);
655 close(ptyfd);
656 return -1;
657 }
658 /* we keep a reference to the pty master */
659 if ((ptymaster = dup(ptyfd)) < 0) {
660 error("%s: dup #2: %s", __func__, strerror(errno));
661 close(ttyfd);
662 close(ptyfd);
663 close(fdout);
664 return -1;
665 }
666
16c343f1 667 /* Fork the child. */
c8c467ee
PA
668 switch ((pid = fork())) {
669 case -1:
670 error("%s: fork: %.100s", __func__, strerror(errno));
671 close(fdout);
672 close(ptymaster);
673 close(ttyfd);
674 close(ptyfd);
675 return -1;
676 case 0:
16c343f1
PA
677 is_child = 1;
678
c8c467ee
PA
679 close(fdout);
680 close(ptymaster);
681
16c343f1 682 /* Child. Reinitialize the log because the pid has changed. */
c8c467ee
PA
683 log_init(__progname, options.log_level,
684 options.log_facility, log_stderr);
16c343f1
PA
685 /* Close the master side of the pseudo tty. */
686 close(ptyfd);
687
688 /* Make the pseudo tty our controlling tty. */
689 pty_make_controlling_tty(&ttyfd, s->tty);
690
691 /* Redirect stdin/stdout/stderr from the pseudo tty. */
692 if (dup2(ttyfd, 0) < 0)
693 error("dup2 stdin: %s", strerror(errno));
694 if (dup2(ttyfd, 1) < 0)
695 error("dup2 stdout: %s", strerror(errno));
696 if (dup2(ttyfd, 2) < 0)
697 error("dup2 stderr: %s", strerror(errno));
698
699 /* Close the extra descriptor for the pseudo tty. */
700 close(ttyfd);
701
702 /* record login, etc. similar to login(1) */
703#ifndef HAVE_OSF_SIA
704 if (!(options.use_login && command == NULL)) {
705#ifdef _UNICOS
706 cray_init_job(s->pw); /* set up cray jid and tmpdir */
707#endif /* _UNICOS */
708 do_login(s, command);
709 }
710# ifdef LOGIN_NEEDS_UTMPX
711 else
712 do_pre_login(s);
713# endif
714#endif
c8c467ee
PA
715 /*
716 * Do common processing for the child, such as execing
717 * the command.
718 */
40c002af
PA
719 do_child(s, command);
720 /* NOTREACHED */
c8c467ee
PA
721 default:
722 break;
16c343f1 723 }
c8c467ee 724
16c343f1
PA
725#ifdef _UNICOS
726 signal(WJSIGNAL, cray_job_termination_handler);
727#endif /* _UNICOS */
728#ifdef HAVE_CYGWIN
40c002af 729 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
16c343f1 730#endif
c8c467ee 731
16c343f1
PA
732 s->pid = pid;
733
734 /* Parent. Close the slave side of the pseudo tty. */
735 close(ttyfd);
736
16c343f1 737 /* Enter interactive session. */
c8c467ee 738 s->ptymaster = ptymaster;
16c343f1
PA
739 packet_set_interactive(1);
740 if (compat20) {
c8c467ee 741 session_set_fds(s, ptyfd, fdout, -1, 1);
16c343f1
PA
742 } else {
743 server_loop(pid, ptyfd, fdout, -1);
744 /* server_loop _has_ closed ptyfd and fdout. */
745 }
c8c467ee 746 return 0;
16c343f1
PA
747}
748
749#ifdef LOGIN_NEEDS_UTMPX
750static void
751do_pre_login(Session *s)
752{
753 socklen_t fromlen;
754 struct sockaddr_storage from;
755 pid_t pid = getpid();
756
757 /*
758 * Get IP address of client. If the connection is not a socket, let
759 * the address be 0.0.0.0.
760 */
761 memset(&from, 0, sizeof(from));
762 fromlen = sizeof(from);
763 if (packet_connection_is_on_socket()) {
764 if (getpeername(packet_get_connection_in(),
765 (struct sockaddr *)&from, &fromlen) < 0) {
766 debug("getpeername: %.100s", strerror(errno));
767 cleanup_exit(255);
768 }
769 }
770
771 record_utmp_only(pid, s->tty, s->pw->pw_name,
772 get_remote_name_or_ip(utmp_len, options.use_dns),
773 (struct sockaddr *)&from, fromlen);
774}
775#endif
776
777/*
778 * This is called to fork and execute a command. If another command is
779 * to be forced, execute that instead.
780 */
c8c467ee 781int
16c343f1
PA
782do_exec(Session *s, const char *command)
783{
c8c467ee
PA
784 int ret;
785
16c343f1
PA
786 if (options.adm_forced_command) {
787 original_command = command;
788 command = options.adm_forced_command;
cb5eb4f1 789 if (IS_INTERNAL_SFTP(command))
16c343f1
PA
790 s->is_subsystem = SUBSYSTEM_INT_SFTP;
791 else if (s->is_subsystem)
792 s->is_subsystem = SUBSYSTEM_EXT;
793 debug("Forced command (config) '%.900s'", command);
794 } else if (forced_command) {
795 original_command = command;
796 command = forced_command;
cb5eb4f1 797 if (IS_INTERNAL_SFTP(command))
16c343f1
PA
798 s->is_subsystem = SUBSYSTEM_INT_SFTP;
799 else if (s->is_subsystem)
800 s->is_subsystem = SUBSYSTEM_EXT;
801 debug("Forced command (key option) '%.900s'", command);
802 }
803
804#ifdef SSH_AUDIT_EVENTS
805 if (command != NULL)
806 PRIVSEP(audit_run_command(command));
807 else if (s->ttyfd == -1) {
808 char *shell = s->pw->pw_shell;
809
810 if (shell[0] == '\0') /* empty shell means /bin/sh */
811 shell =_PATH_BSHELL;
812 PRIVSEP(audit_run_command(shell));
813 }
814#endif
815 if (s->ttyfd != -1)
c8c467ee 816 ret = do_exec_pty(s, command);
16c343f1 817 else
c8c467ee 818 ret = do_exec_no_pty(s, command);
16c343f1
PA
819
820 original_command = NULL;
821
822 /*
823 * Clear loginmsg: it's the child's responsibility to display
824 * it to the user, otherwise multiple sessions may accumulate
825 * multiple copies of the login messages.
826 */
827 buffer_clear(&loginmsg);
c8c467ee
PA
828
829 return ret;
16c343f1
PA
830}
831
832/* administrative, login(1)-like work */
833void
834do_login(Session *s, const char *command)
835{
836 socklen_t fromlen;
837 struct sockaddr_storage from;
838 struct passwd * pw = s->pw;
839 pid_t pid = getpid();
840
841 /*
842 * Get IP address of client. If the connection is not a socket, let
843 * the address be 0.0.0.0.
844 */
845 memset(&from, 0, sizeof(from));
846 fromlen = sizeof(from);
847 if (packet_connection_is_on_socket()) {
848 if (getpeername(packet_get_connection_in(),
40c002af 849 (struct sockaddr *)&from, &fromlen) < 0) {
16c343f1
PA
850 debug("getpeername: %.100s", strerror(errno));
851 cleanup_exit(255);
852 }
853 }
854
855 /* Record that there was a login on that tty from the remote host. */
856 if (!use_privsep)
857 record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
858 get_remote_name_or_ip(utmp_len,
859 options.use_dns),
860 (struct sockaddr *)&from, fromlen);
861
862#ifdef USE_PAM
863 /*
864 * If password change is needed, do it now.
865 * This needs to occur before the ~/.hushlogin check.
866 */
867 if (options.use_pam && !use_privsep && s->authctxt->force_pwchange) {
868 display_loginmsg();
869 do_pam_chauthtok();
870 s->authctxt->force_pwchange = 0;
871 /* XXX - signal [net] parent to enable forwardings */
872 }
873#endif
874
875 if (check_quietlogin(s, command))
876 return;
877
878 display_loginmsg();
879
880 do_motd();
881}
882
883/*
884 * Display the message of the day.
885 */
886void
887do_motd(void)
888{
889 FILE *f;
890 char buf[256];
40948e2d
PA
891#ifdef HAVE_LOGIN_CAP
892 const char *fname;
893#endif
894
895#ifdef HAVE_LOGIN_CAP
896 fname = login_getcapstr(lc, "copyright", NULL, NULL);
897 if (fname != NULL && (f = fopen(fname, "r")) != NULL) {
898 while (fgets(buf, sizeof(buf), f) != NULL)
899 fputs(buf, stdout);
900 fclose(f);
901 } else
902#endif /* HAVE_LOGIN_CAP */
903 (void)printf("%s\n\t%s %s\n",
904 "Copyright (c) 1980, 1983, 1986, 1988, 1990, 1991, 1993, 1994",
905 "The Regents of the University of California. ",
906 "All rights reserved.");
907
908 (void)printf("\n");
16c343f1
PA
909
910 if (options.print_motd) {
911#ifdef HAVE_LOGIN_CAP
912 f = fopen(login_getcapstr(lc, "welcome", "/etc/motd",
913 "/etc/motd"), "r");
914#else
915 f = fopen("/etc/motd", "r");
916#endif
917 if (f) {
918 while (fgets(buf, sizeof(buf), f))
919 fputs(buf, stdout);
920 fclose(f);
921 }
922 }
923}
924
925
926/*
927 * Check for quiet login, either .hushlogin or command given.
928 */
929int
930check_quietlogin(Session *s, const char *command)
931{
932 char buf[256];
933 struct passwd *pw = s->pw;
934 struct stat st;
935
936 /* Return 1 if .hushlogin exists or a command given. */
937 if (command != NULL)
938 return 1;
939 snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
940#ifdef HAVE_LOGIN_CAP
941 if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
942 return 1;
943#else
944 if (stat(buf, &st) >= 0)
945 return 1;
946#endif
947 return 0;
948}
949
950/*
951 * Sets the value of the given variable in the environment. If the variable
cb5eb4f1 952 * already exists, its value is overridden.
16c343f1
PA
953 */
954void
955child_set_env(char ***envp, u_int *envsizep, const char *name,
956 const char *value)
957{
958 char **env;
959 u_int envsize;
960 u_int i, namelen;
961
962 /*
963 * If we're passed an uninitialized list, allocate a single null
964 * entry before continuing.
965 */
966 if (*envp == NULL && *envsizep == 0) {
967 *envp = xmalloc(sizeof(char *));
968 *envp[0] = NULL;
969 *envsizep = 1;
970 }
971
972 /*
973 * Find the slot where the value should be stored. If the variable
974 * already exists, we reuse the slot; otherwise we append a new slot
975 * at the end of the array, expanding if necessary.
976 */
977 env = *envp;
978 namelen = strlen(name);
979 for (i = 0; env[i]; i++)
980 if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
981 break;
982 if (env[i]) {
983 /* Reuse the slot. */
984 xfree(env[i]);
985 } else {
986 /* New variable. Expand if necessary. */
987 envsize = *envsizep;
988 if (i >= envsize - 1) {
989 if (envsize >= 1000)
990 fatal("child_set_env: too many env vars");
991 envsize += 50;
992 env = (*envp) = xrealloc(env, envsize, sizeof(char *));
993 *envsizep = envsize;
994 }
995 /* Need to set the NULL pointer at end of array beyond the new slot. */
996 env[i + 1] = NULL;
997 }
998
999 /* Allocate space and format the variable in the appropriate slot. */
1000 env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
1001 snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
1002}
1003
1004/*
1005 * Reads environment variables from the given file and adds/overrides them
1006 * into the environment. If the file does not exist, this does nothing.
1007 * Otherwise, it must consist of empty lines, comments (line starts with '#')
1008 * and assignments of the form name=value. No other forms are allowed.
1009 */
1010static void
1011read_environment_file(char ***env, u_int *envsize,
1012 const char *filename)
1013{
1014 FILE *f;
1015 char buf[4096];
1016 char *cp, *value;
1017 u_int lineno = 0;
1018
1019 f = fopen(filename, "r");
1020 if (!f)
1021 return;
1022
1023 while (fgets(buf, sizeof(buf), f)) {
1024 if (++lineno > 1000)
1025 fatal("Too many lines in environment file %s", filename);
1026 for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
1027 ;
1028 if (!*cp || *cp == '#' || *cp == '\n')
1029 continue;
1030
1031 cp[strcspn(cp, "\n")] = '\0';
1032
1033 value = strchr(cp, '=');
1034 if (value == NULL) {
1035 fprintf(stderr, "Bad line %u in %.100s\n", lineno,
1036 filename);
1037 continue;
1038 }
1039 /*
1040 * Replace the equals sign by nul, and advance value to
1041 * the value string.
1042 */
1043 *value = '\0';
1044 value++;
1045 child_set_env(env, envsize, cp, value);
1046 }
1047 fclose(f);
1048}
1049
1050#ifdef HAVE_ETC_DEFAULT_LOGIN
1051/*
1052 * Return named variable from specified environment, or NULL if not present.
1053 */
1054static char *
1055child_get_env(char **env, const char *name)
1056{
1057 int i;
1058 size_t len;
1059
1060 len = strlen(name);
1061 for (i=0; env[i] != NULL; i++)
1062 if (strncmp(name, env[i], len) == 0 && env[i][len] == '=')
1063 return(env[i] + len + 1);
1064 return NULL;
1065}
1066
1067/*
1068 * Read /etc/default/login.
1069 * We pick up the PATH (or SUPATH for root) and UMASK.
1070 */
1071static void
1072read_etc_default_login(char ***env, u_int *envsize, uid_t uid)
1073{
1074 char **tmpenv = NULL, *var;
1075 u_int i, tmpenvsize = 0;
1076 u_long mask;
1077
1078 /*
1079 * We don't want to copy the whole file to the child's environment,
1080 * so we use a temporary environment and copy the variables we're
1081 * interested in.
1082 */
1083 read_environment_file(&tmpenv, &tmpenvsize, "/etc/default/login");
1084
1085 if (tmpenv == NULL)
1086 return;
1087
1088 if (uid == 0)
1089 var = child_get_env(tmpenv, "SUPATH");
1090 else
1091 var = child_get_env(tmpenv, "PATH");
1092 if (var != NULL)
1093 child_set_env(env, envsize, "PATH", var);
1094
1095 if ((var = child_get_env(tmpenv, "UMASK")) != NULL)
1096 if (sscanf(var, "%5lo", &mask) == 1)
1097 umask((mode_t)mask);
1098
1099 for (i = 0; tmpenv[i] != NULL; i++)
1100 xfree(tmpenv[i]);
1101 xfree(tmpenv);
1102}
1103#endif /* HAVE_ETC_DEFAULT_LOGIN */
1104
1105void
1106copy_environment(char **source, char ***env, u_int *envsize)
1107{
1108 char *var_name, *var_val;
1109 int i;
1110
1111 if (source == NULL)
1112 return;
1113
1114 for(i = 0; source[i] != NULL; i++) {
1115 var_name = xstrdup(source[i]);
1116 if ((var_val = strstr(var_name, "=")) == NULL) {
1117 xfree(var_name);
1118 continue;
1119 }
1120 *var_val++ = '\0';
1121
1122 debug3("Copy environment: %s=%s", var_name, var_val);
1123 child_set_env(env, envsize, var_name, var_val);
1124
1125 xfree(var_name);
1126 }
1127}
1128
1129static char **
1130do_setup_env(Session *s, const char *shell)
1131{
1132 char buf[256];
1133 u_int i, envsize;
1134 char **env, *laddr;
1135 struct passwd *pw = s->pw;
40c002af 1136#if !defined (HAVE_LOGIN_CAP) && !defined (HAVE_CYGWIN)
16c343f1 1137 char *path = NULL;
40948e2d
PA
1138#else
1139 extern char **environ;
db42c6b8
SW
1140 char **senv;
1141#if 0
1142 char **var;
1143#endif
16c343f1
PA
1144#endif
1145
1146 /* Initialize the environment. */
1147 envsize = 100;
1148 env = xcalloc(envsize, sizeof(char *));
1149 env[0] = NULL;
1150
1151#ifdef HAVE_CYGWIN
1152 /*
1153 * The Windows environment contains some setting which are
1154 * important for a running system. They must not be dropped.
1155 */
1156 {
1157 char **p;
1158
1159 p = fetch_windows_environment();
1160 copy_environment(p, &env, &envsize);
1161 free_windows_environment(p);
1162 }
1163#endif
1164
40948e2d
PA
1165 if (getenv("TZ"))
1166 child_set_env(&env, &envsize, "TZ", getenv("TZ"));
1167
16c343f1
PA
1168#ifdef GSSAPI
1169 /* Allow any GSSAPI methods that we've used to alter
1170 * the childs environment as they see fit
1171 */
1172 ssh_gssapi_do_child(&env, &envsize);
1173#endif
1174
1175 if (!options.use_login) {
1176 /* Set basic environment. */
1177 for (i = 0; i < s->num_env; i++)
1178 child_set_env(&env, &envsize, s->env[i].name,
1179 s->env[i].val);
1180
1181 child_set_env(&env, &envsize, "USER", pw->pw_name);
1182 child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
1183#ifdef _AIX
1184 child_set_env(&env, &envsize, "LOGIN", pw->pw_name);
1185#endif
1186 child_set_env(&env, &envsize, "HOME", pw->pw_dir);
40948e2d
PA
1187 snprintf(buf, sizeof buf, "%.200s/%.50s",
1188 _PATH_MAILDIR, pw->pw_name);
1189 child_set_env(&env, &envsize, "MAIL", buf);
16c343f1 1190#ifdef HAVE_LOGIN_CAP
40948e2d
PA
1191 child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
1192 child_set_env(&env, &envsize, "TERM", "su");
1193 senv = environ;
1194 environ = xmalloc(sizeof(char *));
1195 *environ = NULL;
1196 (void) setusercontext(lc, pw, pw->pw_uid,
1197 LOGIN_SETENV|LOGIN_SETPATH);
1198 copy_environment(environ, &env, &envsize);
5f3ddf32
MD
1199#if 0
1200 /*
1201 * This interferes with libc's management of the environment
1202 * in horrible ways that can cause sshd to crash.
1203 */
40948e2d
PA
1204 for (var = environ; *var != NULL; ++var)
1205 xfree(*var);
1206 xfree(environ);
5f3ddf32 1207#endif
40948e2d 1208 environ = senv;
16c343f1
PA
1209#else /* HAVE_LOGIN_CAP */
1210# ifndef HAVE_CYGWIN
1211 /*
1212 * There's no standard path on Windows. The path contains
1213 * important components pointing to the system directories,
1214 * needed for loading shared libraries. So the path better
1215 * remains intact here.
1216 */
1217# ifdef HAVE_ETC_DEFAULT_LOGIN
1218 read_etc_default_login(&env, &envsize, pw->pw_uid);
1219 path = child_get_env(env, "PATH");
1220# endif /* HAVE_ETC_DEFAULT_LOGIN */
1221 if (path == NULL || *path == '\0') {
1222 child_set_env(&env, &envsize, "PATH",
1223 s->pw->pw_uid == 0 ?
1224 SUPERUSER_PATH : _PATH_STDPATH);
1225 }
1226# endif /* HAVE_CYGWIN */
1227#endif /* HAVE_LOGIN_CAP */
1228
16c343f1
PA
1229 /* Normal systems set SHELL by default. */
1230 child_set_env(&env, &envsize, "SHELL", shell);
1231 }
16c343f1
PA
1232
1233 /* Set custom environment options from RSA authentication. */
1234 if (!options.use_login) {
1235 while (custom_environment) {
1236 struct envstring *ce = custom_environment;
1237 char *str = ce->s;
1238
1239 for (i = 0; str[i] != '=' && str[i]; i++)
1240 ;
1241 if (str[i] == '=') {
1242 str[i] = 0;
1243 child_set_env(&env, &envsize, str, str + i + 1);
1244 }
1245 custom_environment = ce->next;
1246 xfree(ce->s);
1247 xfree(ce);
1248 }
1249 }
1250
1251 /* SSH_CLIENT deprecated */
1252 snprintf(buf, sizeof buf, "%.50s %d %d",
1253 get_remote_ipaddr(), get_remote_port(), get_local_port());
1254 child_set_env(&env, &envsize, "SSH_CLIENT", buf);
1255
1256 laddr = get_local_ipaddr(packet_get_connection_in());
1257 snprintf(buf, sizeof buf, "%.50s %d %.50s %d",
1258 get_remote_ipaddr(), get_remote_port(), laddr, get_local_port());
1259 xfree(laddr);
1260 child_set_env(&env, &envsize, "SSH_CONNECTION", buf);
1261
1262 if (s->ttyfd != -1)
1263 child_set_env(&env, &envsize, "SSH_TTY", s->tty);
1264 if (s->term)
1265 child_set_env(&env, &envsize, "TERM", s->term);
1266 if (s->display)
1267 child_set_env(&env, &envsize, "DISPLAY", s->display);
1268 if (original_command)
1269 child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
1270 original_command);
1271
1272#ifdef _UNICOS
1273 if (cray_tmpdir[0] != '\0')
1274 child_set_env(&env, &envsize, "TMPDIR", cray_tmpdir);
1275#endif /* _UNICOS */
1276
1277 /*
1278 * Since we clear KRB5CCNAME at startup, if it's set now then it
1279 * must have been set by a native authentication method (eg AIX or
1280 * SIA), so copy it to the child.
1281 */
1282 {
1283 char *cp;
1284
1285 if ((cp = getenv("KRB5CCNAME")) != NULL)
1286 child_set_env(&env, &envsize, "KRB5CCNAME", cp);
1287 }
1288
1289#ifdef _AIX
1290 {
1291 char *cp;
1292
1293 if ((cp = getenv("AUTHSTATE")) != NULL)
1294 child_set_env(&env, &envsize, "AUTHSTATE", cp);
1295 read_environment_file(&env, &envsize, "/etc/environment");
1296 }
1297#endif
1298#ifdef KRB5
1299 if (s->authctxt->krb5_ccname)
1300 child_set_env(&env, &envsize, "KRB5CCNAME",
1301 s->authctxt->krb5_ccname);
1302#endif
1303#ifdef USE_PAM
1304 /*
1305 * Pull in any environment variables that may have
1306 * been set by PAM.
1307 */
1308 if (options.use_pam) {
1309 char **p;
1310
1311 p = fetch_pam_child_environment();
1312 copy_environment(p, &env, &envsize);
1313 free_pam_environment(p);
1314
1315 p = fetch_pam_environment();
1316 copy_environment(p, &env, &envsize);
1317 free_pam_environment(p);
1318 }
1319#endif /* USE_PAM */
1320
1321 if (auth_sock_name != NULL)
1322 child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
1323 auth_sock_name);
1324
1325 /* read $HOME/.ssh/environment. */
1326 if (options.permit_user_env && !options.use_login) {
1327 snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
1328 strcmp(pw->pw_dir, "/") ? pw->pw_dir : "");
1329 read_environment_file(&env, &envsize, buf);
1330 }
1331 if (debug_flag) {
1332 /* dump the environment */
1333 fprintf(stderr, "Environment:\n");
1334 for (i = 0; env[i]; i++)
1335 fprintf(stderr, " %.200s\n", env[i]);
1336 }
1337 return env;
1338}
1339
1340/*
1341 * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found
1342 * first in this order).
1343 */
1344static void
1345do_rc_files(Session *s, const char *shell)
1346{
1347 FILE *f = NULL;
1348 char cmd[1024];
1349 int do_xauth;
1350 struct stat st;
1351
1352 do_xauth =
1353 s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
1354
1355 /* ignore _PATH_SSH_USER_RC for subsystems and admin forced commands */
1356 if (!s->is_subsystem && options.adm_forced_command == NULL &&
c8c467ee 1357 !no_user_rc && stat(_PATH_SSH_USER_RC, &st) >= 0) {
16c343f1
PA
1358 snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
1359 shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
1360 if (debug_flag)
1361 fprintf(stderr, "Running %s\n", cmd);
1362 f = popen(cmd, "w");
1363 if (f) {
1364 if (do_xauth)
1365 fprintf(f, "%s %s\n", s->auth_proto,
1366 s->auth_data);
1367 pclose(f);
1368 } else
1369 fprintf(stderr, "Could not run %s\n",
1370 _PATH_SSH_USER_RC);
1371 } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
1372 if (debug_flag)
1373 fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
1374 _PATH_SSH_SYSTEM_RC);
1375 f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
1376 if (f) {
1377 if (do_xauth)
1378 fprintf(f, "%s %s\n", s->auth_proto,
1379 s->auth_data);
1380 pclose(f);
1381 } else
1382 fprintf(stderr, "Could not run %s\n",
1383 _PATH_SSH_SYSTEM_RC);
1384 } else if (do_xauth && options.xauth_location != NULL) {
1385 /* Add authority data to .Xauthority if appropriate. */
1386 if (debug_flag) {
1387 fprintf(stderr,
1388 "Running %.500s remove %.100s\n",
1389 options.xauth_location, s->auth_display);
1390 fprintf(stderr,
1391 "%.500s add %.100s %.100s %.100s\n",
1392 options.xauth_location, s->auth_display,
1393 s->auth_proto, s->auth_data);
1394 }
1395 snprintf(cmd, sizeof cmd, "%s -q -",
1396 options.xauth_location);
1397 f = popen(cmd, "w");
1398 if (f) {
1399 fprintf(f, "remove %s\n",
1400 s->auth_display);
1401 fprintf(f, "add %s %s %s\n",
1402 s->auth_display, s->auth_proto,
1403 s->auth_data);
1404 pclose(f);
1405 } else {
1406 fprintf(stderr, "Could not run %s\n",
1407 cmd);
1408 }
1409 }
1410}
1411
1412static void
1413do_nologin(struct passwd *pw)
1414{
1415 FILE *f = NULL;
1416 char buf[1024];
1417
1418#ifdef HAVE_LOGIN_CAP
1419 if (!login_getcapbool(lc, "ignorenologin", 0) && pw->pw_uid)
1420 f = fopen(login_getcapstr(lc, "nologin", _PATH_NOLOGIN,
1421 _PATH_NOLOGIN), "r");
1422#else
1423 if (pw->pw_uid)
1424 f = fopen(_PATH_NOLOGIN, "r");
1425#endif
1426 if (f) {
1427 /* /etc/nologin exists. Print its contents and exit. */
1428 logit("User %.100s not allowed because %s exists",
1429 pw->pw_name, _PATH_NOLOGIN);
1430 while (fgets(buf, sizeof(buf), f))
1431 fputs(buf, stderr);
1432 fclose(f);
1433 fflush(NULL);
1434 exit(254);
1435 }
1436}
1437
1438/*
1439 * Chroot into a directory after checking it for safety: all path components
1440 * must be root-owned directories with strict permissions.
1441 */
1442static void
1443safely_chroot(const char *path, uid_t uid)
1444{
1445 const char *cp;
1446 char component[MAXPATHLEN];
1447 struct stat st;
1448
1449 if (*path != '/')
1450 fatal("chroot path does not begin at root");
1451 if (strlen(path) >= sizeof(component))
1452 fatal("chroot path too long");
1453
1454 /*
1455 * Descend the path, checking that each component is a
1456 * root-owned directory with strict permissions.
1457 */
1458 for (cp = path; cp != NULL;) {
1459 if ((cp = strchr(cp, '/')) == NULL)
1460 strlcpy(component, path, sizeof(component));
1461 else {
1462 cp++;
1463 memcpy(component, path, cp - path);
1464 component[cp - path] = '\0';
1465 }
1466
1467 debug3("%s: checking '%s'", __func__, component);
1468
1469 if (stat(component, &st) != 0)
1470 fatal("%s: stat(\"%s\"): %s", __func__,
1471 component, strerror(errno));
1472 if (st.st_uid != 0 || (st.st_mode & 022) != 0)
1473 fatal("bad ownership or modes for chroot "
1474 "directory %s\"%s\"",
1475 cp == NULL ? "" : "component ", component);
1476 if (!S_ISDIR(st.st_mode))
1477 fatal("chroot path %s\"%s\" is not a directory",
1478 cp == NULL ? "" : "component ", component);
1479
1480 }
1481
1482 if (chdir(path) == -1)
1483 fatal("Unable to chdir to chroot path \"%s\": "
1484 "%s", path, strerror(errno));
1485 if (chroot(path) == -1)
1486 fatal("chroot(\"%s\"): %s", path, strerror(errno));
1487 if (chdir("/") == -1)
1488 fatal("%s: chdir(/) after chroot: %s",
1489 __func__, strerror(errno));
1490 verbose("Changed root directory to \"%s\"", path);
1491}
1492
1493/* Set login name, uid, gid, and groups. */
1494void
1495do_setusercontext(struct passwd *pw)
1496{
1497 char *chroot_path, *tmp;
1498
1499#ifdef WITH_SELINUX
1500 /* Cache selinux status for later use */
1501 (void)ssh_selinux_enabled();
1502#endif
1503
1504#ifndef HAVE_CYGWIN
1505 if (getuid() == 0 || geteuid() == 0)
1506#endif /* HAVE_CYGWIN */
1507 {
16c343f1
PA
1508#ifdef HAVE_LOGIN_CAP
1509# ifdef __bsdi__
1510 setpgid(0, 0);
1511# endif
1512# ifdef USE_PAM
1513 if (options.use_pam) {
1514 do_pam_setcred(use_privsep);
1515 }
1516# endif /* USE_PAM */
1517 if (setusercontext(lc, pw, pw->pw_uid,
1518 (LOGIN_SETALL & ~(LOGIN_SETPATH|LOGIN_SETUSER))) < 0) {
1519 perror("unable to set user context");
1520 exit(1);
1521 }
1522#else
1523# if defined(HAVE_GETLUID) && defined(HAVE_SETLUID)
1524 /* Sets login uid for accounting */
1525 if (getluid() == -1 && setluid(pw->pw_uid) == -1)
1526 error("setluid: %s", strerror(errno));
1527# endif /* defined(HAVE_GETLUID) && defined(HAVE_SETLUID) */
1528
1529 if (setlogin(pw->pw_name) < 0)
1530 error("setlogin failed: %s", strerror(errno));
1531 if (setgid(pw->pw_gid) < 0) {
1532 perror("setgid");
1533 exit(1);
1534 }
1535 /* Initialize the group list. */
1536 if (initgroups(pw->pw_name, pw->pw_gid) < 0) {
1537 perror("initgroups");
1538 exit(1);
1539 }
1540 endgrent();
1541# ifdef USE_PAM
1542 /*
1543 * PAM credentials may take the form of supplementary groups.
1544 * These will have been wiped by the above initgroups() call.
1545 * Reestablish them here.
1546 */
1547 if (options.use_pam) {
1548 do_pam_setcred(use_privsep);
1549 }
1550# endif /* USE_PAM */
1551# if defined(WITH_IRIX_PROJECT) || defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY)
1552 irix_setusercontext(pw);
1553# endif /* defined(WITH_IRIX_PROJECT) || defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY) */
1554# ifdef _AIX
1555 aix_usrinfo(pw);
1556# endif /* _AIX */
1557# ifdef USE_LIBIAF
1558 if (set_id(pw->pw_name) != 0) {
1559 exit(1);
1560 }
1561# endif /* USE_LIBIAF */
1562#endif
1563
1564 if (options.chroot_directory != NULL &&
1565 strcasecmp(options.chroot_directory, "none") != 0) {
1566 tmp = tilde_expand_filename(options.chroot_directory,
1567 pw->pw_uid);
1568 chroot_path = percent_expand(tmp, "h", pw->pw_dir,
1569 "u", pw->pw_name, (char *)NULL);
1570 safely_chroot(chroot_path, pw->pw_uid);
1571 free(tmp);
1572 free(chroot_path);
1573 }
1574
40c002af
PA
1575#ifdef HAVE_SETPCRED
1576 if (setpcred(pw->pw_name, (char **)NULL) == -1)
1577 fatal("Failed to set process credentials");
1578#endif /* HAVE_SETPCRED */
16c343f1
PA
1579#ifdef HAVE_LOGIN_CAP
1580 if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUSER) < 0) {
1581 perror("unable to set user context (setuser)");
1582 exit(1);
1583 }
1584#else
1585 /* Permanently switch to the desired uid. */
1586 permanently_set_uid(pw);
1587#endif
1588 }
1589
16c343f1
PA
1590 if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
1591 fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
1592
1593#ifdef WITH_SELINUX
1594 ssh_selinux_setup_exec_context(pw->pw_name);
1595#endif
1596}
1597
1598static void
1599do_pwchange(Session *s)
1600{
1601 fflush(NULL);
1602 fprintf(stderr, "WARNING: Your password has expired.\n");
1603 if (s->ttyfd != -1) {
1604 fprintf(stderr,
1605 "You must change your password now and login again!\n");
1606#ifdef PASSWD_NEEDS_USERNAME
1607 execl(_PATH_PASSWD_PROG, "passwd", s->pw->pw_name,
1608 (char *)NULL);
1609#else
1610 execl(_PATH_PASSWD_PROG, "passwd", (char *)NULL);
1611#endif
1612 perror("passwd");
1613 } else {
1614 fprintf(stderr,
1615 "Password change required but no TTY available.\n");
1616 }
1617 exit(1);
1618}
1619
1620static void
1621launch_login(struct passwd *pw, const char *hostname)
1622{
1623 /* Launch login(1). */
1624
1625 execl(LOGIN_PROGRAM, "login", "-h", hostname,
1626#ifdef xxxLOGIN_NEEDS_TERM
1627 (s->term ? s->term : "unknown"),
1628#endif /* LOGIN_NEEDS_TERM */
1629#ifdef LOGIN_NO_ENDOPT
1630 "-p", "-f", pw->pw_name, (char *)NULL);
1631#else
1632 "-p", "-f", "--", pw->pw_name, (char *)NULL);
1633#endif
1634
1635 /* Login couldn't be executed, die. */
1636
1637 perror("login");
1638 exit(1);
1639}
1640
1641static void
1642child_close_fds(void)
1643{
1644 int i;
1645
1646 if (packet_get_connection_in() == packet_get_connection_out())
1647 close(packet_get_connection_in());
1648 else {
1649 close(packet_get_connection_in());
1650 close(packet_get_connection_out());
1651 }
1652 /*
1653 * Close all descriptors related to channels. They will still remain
1654 * open in the parent.
1655 */
1656 /* XXX better use close-on-exec? -markus */
1657 channel_close_all();
1658
1659 /*
1660 * Close any extra file descriptors. Note that there may still be
1661 * descriptors left by system functions. They will be closed later.
1662 */
1663 endpwent();
1664
1665 /*
1666 * Close any extra open file descriptors so that we don't have them
1667 * hanging around in clients. Note that we want to do this after
1668 * initgroups, because at least on Solaris 2.3 it leaves file
1669 * descriptors open.
1670 */
1671 for (i = 3; i < 64; i++)
1672 close(i);
1673}
1674
1675/*
1676 * Performs common processing for the child, such as setting up the
1677 * environment, closing extra file descriptors, setting the user and group
1678 * ids, and executing the command or shell.
1679 */
1680#define ARGV_MAX 10
1681void
1682do_child(Session *s, const char *command)
1683{
1684 extern char **environ;
1685 char **env;
1686 char *argv[ARGV_MAX];
1687 const char *shell, *shell0, *hostname = NULL;
1688 struct passwd *pw = s->pw;
c8c467ee 1689 int r = 0;
16c343f1
PA
1690
1691 /* remove hostkey from the child's memory */
1692 destroy_sensitive_data();
1693
1694 /* Force a password change */
1695 if (s->authctxt->force_pwchange) {
1696 do_setusercontext(pw);
1697 child_close_fds();
1698 do_pwchange(s);
1699 exit(1);
1700 }
1701
1702 /* login(1) is only called if we execute the login shell */
1703 if (options.use_login && command != NULL)
1704 options.use_login = 0;
1705
1706#ifdef _UNICOS
1707 cray_setup(pw->pw_uid, pw->pw_name, command);
1708#endif /* _UNICOS */
1709
1710 /*
1711 * Login(1) does this as well, and it needs uid 0 for the "-h"
1712 * switch, so we let login(1) to this for us.
1713 */
1714 if (!options.use_login) {
1715#ifdef HAVE_OSF_SIA
1716 session_setup_sia(pw, s->ttyfd == -1 ? NULL : s->tty);
1717 if (!check_quietlogin(s, command))
1718 do_motd();
1719#else /* HAVE_OSF_SIA */
1720 /* When PAM is enabled we rely on it to do the nologin check */
1721 if (!options.use_pam)
1722 do_nologin(pw);
1723 do_setusercontext(pw);
1724 /*
1725 * PAM session modules in do_setusercontext may have
1726 * generated messages, so if this in an interactive
1727 * login then display them too.
1728 */
1729 if (!check_quietlogin(s, command))
1730 display_loginmsg();
1731#endif /* HAVE_OSF_SIA */
1732 }
1733
1734#ifdef USE_PAM
1735 if (options.use_pam && !options.use_login && !is_pam_session_open()) {
1736 debug3("PAM session not opened, exiting");
1737 display_loginmsg();
1738 exit(254);
1739 }
1740#endif
1741
1742 /*
1743 * Get the shell from the password data. An empty shell field is
1744 * legal, and means /bin/sh.
1745 */
1746 shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1747
1748 /*
1749 * Make sure $SHELL points to the shell from the password file,
1750 * even if shell is overridden from login.conf
1751 */
1752 env = do_setup_env(s, shell);
1753
1754#ifdef HAVE_LOGIN_CAP
1755 shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
1756#endif
1757
1758 /* we have to stash the hostname before we close our socket. */
1759 if (options.use_login)
1760 hostname = get_remote_name_or_ip(utmp_len,
1761 options.use_dns);
1762 /*
1763 * Close the connection descriptors; note that this is the child, and
1764 * the server will still have the socket open, and it is important
1765 * that we do not shutdown it. Note that the descriptors cannot be
1766 * closed before building the environment, as we call
1767 * get_remote_ipaddr there.
1768 */
1769 child_close_fds();
1770
1771 /*
1772 * Must take new environment into use so that .ssh/rc,
1773 * /etc/ssh/sshrc and xauth are run in the proper environment.
1774 */
1775 environ = env;
1776
1777#if defined(KRB5) && defined(USE_AFS)
1778 /*
1779 * At this point, we check to see if AFS is active and if we have
1780 * a valid Kerberos 5 TGT. If so, it seems like a good idea to see
1781 * if we can (and need to) extend the ticket into an AFS token. If
1782 * we don't do this, we run into potential problems if the user's
1783 * home directory is in AFS and it's not world-readable.
1784 */
1785
1786 if (options.kerberos_get_afs_token && k_hasafs() &&
1787 (s->authctxt->krb5_ctx != NULL)) {
1788 char cell[64];
1789
1790 debug("Getting AFS token");
1791
1792 k_setpag();
1793
1794 if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
1795 krb5_afslog(s->authctxt->krb5_ctx,
1796 s->authctxt->krb5_fwd_ccache, cell, NULL);
1797
1798 krb5_afslog_home(s->authctxt->krb5_ctx,
1799 s->authctxt->krb5_fwd_ccache, NULL, NULL, pw->pw_dir);
1800 }
1801#endif
1802
1803 /* Change current directory to the user's home directory. */
1804 if (chdir(pw->pw_dir) < 0) {
c8c467ee 1805 /* Suppress missing homedir warning for chroot case */
16c343f1 1806#ifdef HAVE_LOGIN_CAP
c8c467ee 1807 r = login_getcapbool(lc, "requirehome", 0);
16c343f1 1808#endif
c8c467ee
PA
1809 if (r || options.chroot_directory == NULL)
1810 fprintf(stderr, "Could not chdir to home "
1811 "directory %s: %s\n", pw->pw_dir,
1812 strerror(errno));
1813 if (r)
1814 exit(1);
16c343f1
PA
1815 }
1816
1817 closefrom(STDERR_FILENO + 1);
1818
1819 if (!options.use_login)
1820 do_rc_files(s, shell);
1821
1822 /* restore SIGPIPE for child */
1823 signal(SIGPIPE, SIG_DFL);
1824
1825 if (s->is_subsystem == SUBSYSTEM_INT_SFTP) {
1826 extern int optind, optreset;
1827 int i;
1828 char *p, *args;
1829
40c002af 1830 setproctitle("%s@%s", s->pw->pw_name, INTERNAL_SFTP_NAME);
cb5eb4f1 1831 args = xstrdup(command ? command : "sftp-server");
16c343f1
PA
1832 for (i = 0, (p = strtok(args, " ")); p; (p = strtok(NULL, " ")))
1833 if (i < ARGV_MAX - 1)
1834 argv[i++] = p;
1835 argv[i] = NULL;
1836 optind = optreset = 1;
1837 __progname = argv[0];
1838 exit(sftp_server_main(i, argv, s->pw));
1839 }
1840
1841 if (options.use_login) {
1842 launch_login(pw, hostname);
1843 /* NEVERREACHED */
1844 }
1845
1846 /* Get the last component of the shell name. */
1847 if ((shell0 = strrchr(shell, '/')) != NULL)
1848 shell0++;
1849 else
1850 shell0 = shell;
1851
1852 /*
1853 * If we have no command, execute the shell. In this case, the shell
1854 * name to be passed in argv[0] is preceded by '-' to indicate that
1855 * this is a login shell.
1856 */
1857 if (!command) {
1858 char argv0[256];
1859
1860 /* Start the shell. Set initial character to '-'. */
1861 argv0[0] = '-';
1862
1863 if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1)
1864 >= sizeof(argv0) - 1) {
1865 errno = EINVAL;
1866 perror(shell);
1867 exit(1);
1868 }
1869
1870 /* Execute the shell. */
1871 argv[0] = argv0;
1872 argv[1] = NULL;
1873 execve(shell, argv, env);
1874
1875 /* Executing the shell failed. */
1876 perror(shell);
1877 exit(1);
1878 }
1879 /*
1880 * Execute the command using the user's shell. This uses the -c
1881 * option to execute the command.
1882 */
1883 argv[0] = (char *) shell0;
1884 argv[1] = "-c";
1885 argv[2] = (char *) command;
1886 argv[3] = NULL;
1887 execve(shell, argv, env);
1888 perror(shell);
1889 exit(1);
1890}
1891
c8c467ee
PA
1892void
1893session_unused(int id)
1894{
1895 debug3("%s: session id %d unused", __func__, id);
1896 if (id >= options.max_sessions ||
1897 id >= sessions_nalloc) {
1898 fatal("%s: insane session id %d (max %d nalloc %d)",
1899 __func__, id, options.max_sessions, sessions_nalloc);
1900 }
1901 bzero(&sessions[id], sizeof(*sessions));
1902 sessions[id].self = id;
1903 sessions[id].used = 0;
1904 sessions[id].chanid = -1;
1905 sessions[id].ptyfd = -1;
1906 sessions[id].ttyfd = -1;
1907 sessions[id].ptymaster = -1;
1908 sessions[id].x11_chanids = NULL;
1909 sessions[id].next_unused = sessions_first_unused;
1910 sessions_first_unused = id;
1911}
1912
16c343f1
PA
1913Session *
1914session_new(void)
1915{
c8c467ee
PA
1916 Session *s, *tmp;
1917
1918 if (sessions_first_unused == -1) {
1919 if (sessions_nalloc >= options.max_sessions)
1920 return NULL;
1921 debug2("%s: allocate (allocated %d max %d)",
1922 __func__, sessions_nalloc, options.max_sessions);
1923 tmp = xrealloc(sessions, sessions_nalloc + 1,
1924 sizeof(*sessions));
1925 if (tmp == NULL) {
1926 error("%s: cannot allocate %d sessions",
1927 __func__, sessions_nalloc + 1);
1928 return NULL;
16c343f1 1929 }
c8c467ee
PA
1930 sessions = tmp;
1931 session_unused(sessions_nalloc++);
16c343f1 1932 }
c8c467ee
PA
1933
1934 if (sessions_first_unused >= sessions_nalloc ||
1935 sessions_first_unused < 0) {
1936 fatal("%s: insane first_unused %d max %d nalloc %d",
1937 __func__, sessions_first_unused, options.max_sessions,
1938 sessions_nalloc);
16c343f1 1939 }
c8c467ee
PA
1940
1941 s = &sessions[sessions_first_unused];
1942 if (s->used) {
1943 fatal("%s: session %d already used",
1944 __func__, sessions_first_unused);
1945 }
1946 sessions_first_unused = s->next_unused;
1947 s->used = 1;
1948 s->next_unused = -1;
1949 debug("session_new: session %d", s->self);
1950
1951 return s;
16c343f1
PA
1952}
1953
1954static void
1955session_dump(void)
1956{
1957 int i;
c8c467ee 1958 for (i = 0; i < sessions_nalloc; i++) {
16c343f1 1959 Session *s = &sessions[i];
c8c467ee
PA
1960
1961 debug("dump: used %d next_unused %d session %d %p "
1962 "channel %d pid %ld",
16c343f1 1963 s->used,
c8c467ee 1964 s->next_unused,
16c343f1
PA
1965 s->self,
1966 s,
1967 s->chanid,
1968 (long)s->pid);
1969 }
1970}
1971
1972int
1973session_open(Authctxt *authctxt, int chanid)
1974{
1975 Session *s = session_new();
1976 debug("session_open: channel %d", chanid);
1977 if (s == NULL) {
1978 error("no more sessions");
1979 return 0;
1980 }
1981 s->authctxt = authctxt;
1982 s->pw = authctxt->pw;
1983 if (s->pw == NULL || !authctxt->valid)
1984 fatal("no user for session %d", s->self);
1985 debug("session_open: session %d: link with channel %d", s->self, chanid);
1986 s->chanid = chanid;
1987 return 1;
1988}
1989
1990Session *
1991session_by_tty(char *tty)
1992{
1993 int i;
c8c467ee 1994 for (i = 0; i < sessions_nalloc; i++) {
16c343f1
PA
1995 Session *s = &sessions[i];
1996 if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) {
1997 debug("session_by_tty: session %d tty %s", i, tty);
1998 return s;
1999 }
2000 }
2001 debug("session_by_tty: unknown tty %.100s", tty);
2002 session_dump();
2003 return NULL;
2004}
2005
2006static Session *
2007session_by_channel(int id)
2008{
2009 int i;
c8c467ee 2010 for (i = 0; i < sessions_nalloc; i++) {
16c343f1
PA
2011 Session *s = &sessions[i];
2012 if (s->used && s->chanid == id) {
c8c467ee
PA
2013 debug("session_by_channel: session %d channel %d",
2014 i, id);
16c343f1
PA
2015 return s;
2016 }
2017 }
2018 debug("session_by_channel: unknown channel %d", id);
2019 session_dump();
2020 return NULL;
2021}
2022
2023static Session *
2024session_by_x11_channel(int id)
2025{
2026 int i, j;
2027
c8c467ee 2028 for (i = 0; i < sessions_nalloc; i++) {
16c343f1
PA
2029 Session *s = &sessions[i];
2030
2031 if (s->x11_chanids == NULL || !s->used)
2032 continue;
2033 for (j = 0; s->x11_chanids[j] != -1; j++) {
2034 if (s->x11_chanids[j] == id) {
2035 debug("session_by_x11_channel: session %d "
2036 "channel %d", s->self, id);
2037 return s;
2038 }
2039 }
2040 }
2041 debug("session_by_x11_channel: unknown channel %d", id);
2042 session_dump();
2043 return NULL;
2044}
2045
2046static Session *
2047session_by_pid(pid_t pid)
2048{
2049 int i;
2050 debug("session_by_pid: pid %ld", (long)pid);
c8c467ee 2051 for (i = 0; i < sessions_nalloc; i++) {
16c343f1
PA
2052 Session *s = &sessions[i];
2053 if (s->used && s->pid == pid)
2054 return s;
2055 }
2056 error("session_by_pid: unknown pid %ld", (long)pid);
2057 session_dump();
2058 return NULL;
2059}
2060
2061static int
2062session_window_change_req(Session *s)
2063{
2064 s->col = packet_get_int();
2065 s->row = packet_get_int();
2066 s->xpixel = packet_get_int();
2067 s->ypixel = packet_get_int();
2068 packet_check_eom();
2069 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
2070 return 1;
2071}
2072
2073static int
2074session_pty_req(Session *s)
2075{
2076 u_int len;
2077 int n_bytes;
2078
2079 if (no_pty_flag) {
2080 debug("Allocating a pty not permitted for this authentication.");
2081 return 0;
2082 }
2083 if (s->ttyfd != -1) {
2084 packet_disconnect("Protocol error: you already have a pty.");
2085 return 0;
2086 }
2087
2088 s->term = packet_get_string(&len);
2089
2090 if (compat20) {
2091 s->col = packet_get_int();
2092 s->row = packet_get_int();
2093 } else {
2094 s->row = packet_get_int();
2095 s->col = packet_get_int();
2096 }
2097 s->xpixel = packet_get_int();
2098 s->ypixel = packet_get_int();
2099
2100 if (strcmp(s->term, "") == 0) {
2101 xfree(s->term);
2102 s->term = NULL;
2103 }
2104
2105 /* Allocate a pty and open it. */
2106 debug("Allocating pty.");
c8c467ee
PA
2107 if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty,
2108 sizeof(s->tty)))) {
16c343f1
PA
2109 if (s->term)
2110 xfree(s->term);
2111 s->term = NULL;
2112 s->ptyfd = -1;
2113 s->ttyfd = -1;
2114 error("session_pty_req: session %d alloc failed", s->self);
2115 return 0;
2116 }
2117 debug("session_pty_req: session %d alloc %s", s->self, s->tty);
2118
2119 /* for SSH1 the tty modes length is not given */
2120 if (!compat20)
2121 n_bytes = packet_remaining();
2122 tty_parse_modes(s->ttyfd, &n_bytes);
2123
2124 if (!use_privsep)
2125 pty_setowner(s->pw, s->tty);
2126
2127 /* Set window size from the packet. */
2128 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
2129
2130 packet_check_eom();
2131 session_proctitle(s);
2132 return 1;
2133}
2134
2135static int
2136session_subsystem_req(Session *s)
2137{
2138 struct stat st;
2139 u_int len;
2140 int success = 0;
2141 char *prog, *cmd, *subsys = packet_get_string(&len);
2142 u_int i;
2143
2144 packet_check_eom();
2145 logit("subsystem request for %.100s", subsys);
2146
2147 for (i = 0; i < options.num_subsystems; i++) {
2148 if (strcmp(subsys, options.subsystem_name[i]) == 0) {
2149 prog = options.subsystem_command[i];
2150 cmd = options.subsystem_args[i];
2151 if (!strcmp(INTERNAL_SFTP_NAME, prog)) {
2152 s->is_subsystem = SUBSYSTEM_INT_SFTP;
2153 } else if (stat(prog, &st) < 0) {
2154 error("subsystem: cannot stat %s: %s", prog,
2155 strerror(errno));
2156 break;
2157 } else {
2158 s->is_subsystem = SUBSYSTEM_EXT;
2159 }
2160 debug("subsystem: exec() %s", cmd);
c8c467ee 2161 success = do_exec(s, cmd) == 0;
16c343f1
PA
2162 break;
2163 }
2164 }
2165
2166 if (!success)
2167 logit("subsystem request for %.100s failed, subsystem not found",
2168 subsys);
2169
2170 xfree(subsys);
2171 return success;
2172}
2173
2174static int
2175session_x11_req(Session *s)
2176{
2177 int success;
2178
2179 if (s->auth_proto != NULL || s->auth_data != NULL) {
2180 error("session_x11_req: session %d: "
2181 "x11 forwarding already active", s->self);
2182 return 0;
2183 }
2184 s->single_connection = packet_get_char();
2185 s->auth_proto = packet_get_string(NULL);
2186 s->auth_data = packet_get_string(NULL);
2187 s->screen = packet_get_int();
2188 packet_check_eom();
2189
2190 success = session_setup_x11fwd(s);
2191 if (!success) {
2192 xfree(s->auth_proto);
2193 xfree(s->auth_data);
2194 s->auth_proto = NULL;
2195 s->auth_data = NULL;
2196 }
2197 return success;
2198}
2199
2200static int
2201session_shell_req(Session *s)
2202{
2203 packet_check_eom();
c8c467ee 2204 return do_exec(s, NULL) == 0;
16c343f1
PA
2205}
2206
2207static int
2208session_exec_req(Session *s)
2209{
c8c467ee
PA
2210 u_int len, success;
2211
16c343f1
PA
2212 char *command = packet_get_string(&len);
2213 packet_check_eom();
c8c467ee 2214 success = do_exec(s, command) == 0;
16c343f1 2215 xfree(command);
c8c467ee 2216 return success;
16c343f1
PA
2217}
2218
2219static int
2220session_break_req(Session *s)
2221{
2222
2223 packet_get_int(); /* ignored */
2224 packet_check_eom();
2225
c8c467ee 2226 if (s->ttyfd == -1 || tcsendbreak(s->ttyfd, 0) < 0)
16c343f1
PA
2227 return 0;
2228 return 1;
2229}
2230
2231static int
2232session_env_req(Session *s)
2233{
2234 char *name, *val;
2235 u_int name_len, val_len, i;
2236
2237 name = packet_get_string(&name_len);
2238 val = packet_get_string(&val_len);
2239 packet_check_eom();
2240
2241 /* Don't set too many environment variables */
2242 if (s->num_env > 128) {
2243 debug2("Ignoring env request %s: too many env vars", name);
2244 goto fail;
2245 }
2246
2247 for (i = 0; i < options.num_accept_env; i++) {
2248 if (match_pattern(name, options.accept_env[i])) {
2249 debug2("Setting env %d: %s=%s", s->num_env, name, val);
2250 s->env = xrealloc(s->env, s->num_env + 1,
2251 sizeof(*s->env));
2252 s->env[s->num_env].name = name;
2253 s->env[s->num_env].val = val;
2254 s->num_env++;
2255 return (1);
2256 }
2257 }
2258 debug2("Ignoring env request %s: disallowed name", name);
2259
2260 fail:
2261 xfree(name);
2262 xfree(val);
2263 return (0);
2264}
2265
2266static int
2267session_auth_agent_req(Session *s)
2268{
2269 static int called = 0;
2270 packet_check_eom();
c8c467ee 2271 if (no_agent_forwarding_flag || !options.allow_agent_forwarding) {
16c343f1
PA
2272 debug("session_auth_agent_req: no_agent_forwarding_flag");
2273 return 0;
2274 }
2275 if (called) {
2276 return 0;
2277 } else {
2278 called = 1;
2279 return auth_input_request_forwarding(s->pw);
2280 }
2281}
2282
2283int
2284session_input_channel_req(Channel *c, const char *rtype)
2285{
2286 int success = 0;
2287 Session *s;
2288
2289 if ((s = session_by_channel(c->self)) == NULL) {
2290 logit("session_input_channel_req: no session %d req %.100s",
2291 c->self, rtype);
2292 return 0;
2293 }
2294 debug("session_input_channel_req: session %d req %s", s->self, rtype);
2295
2296 /*
2297 * a session is in LARVAL state until a shell, a command
2298 * or a subsystem is executed
2299 */
2300 if (c->type == SSH_CHANNEL_LARVAL) {
2301 if (strcmp(rtype, "shell") == 0) {
2302 success = session_shell_req(s);
2303 } else if (strcmp(rtype, "exec") == 0) {
2304 success = session_exec_req(s);
2305 } else if (strcmp(rtype, "pty-req") == 0) {
2306 success = session_pty_req(s);
2307 } else if (strcmp(rtype, "x11-req") == 0) {
2308 success = session_x11_req(s);
2309 } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
2310 success = session_auth_agent_req(s);
2311 } else if (strcmp(rtype, "subsystem") == 0) {
2312 success = session_subsystem_req(s);
2313 } else if (strcmp(rtype, "env") == 0) {
2314 success = session_env_req(s);
2315 }
2316 }
2317 if (strcmp(rtype, "window-change") == 0) {
2318 success = session_window_change_req(s);
2319 } else if (strcmp(rtype, "break") == 0) {
2320 success = session_break_req(s);
2321 }
2322
2323 return success;
2324}
2325
2326void
c8c467ee 2327session_set_fds(Session *s, int fdin, int fdout, int fderr, int is_tty)
16c343f1
PA
2328{
2329 if (!compat20)
2330 fatal("session_set_fds: called for proto != 2.0");
2331 /*
2332 * now that have a child and a pipe to the child,
2333 * we can activate our channel and register the fd's
2334 */
2335 if (s->chanid == -1)
2336 fatal("no channel for session %d", s->self);
c29cd1cc 2337 if (options.hpn_disabled)
16c343f1
PA
2338 channel_set_fds(s->chanid,
2339 fdout, fdin, fderr,
2340 fderr == -1 ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
c8c467ee 2341 1, is_tty, CHAN_SES_WINDOW_DEFAULT);
c29cd1cc
PA
2342 else
2343 channel_set_fds(s->chanid,
2344 fdout, fdin, fderr,
2345 fderr == -1 ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
2346 1, is_tty, options.hpn_buffer_size);
16c343f1
PA
2347}
2348
2349/*
2350 * Function to perform pty cleanup. Also called if we get aborted abnormally
2351 * (e.g., due to a dropped connection).
2352 */
2353void
2354session_pty_cleanup2(Session *s)
2355{
2356 if (s == NULL) {
2357 error("session_pty_cleanup: no session");
2358 return;
2359 }
2360 if (s->ttyfd == -1)
2361 return;
2362
2363 debug("session_pty_cleanup: session %d release %s", s->self, s->tty);
2364
2365 /* Record that the user has logged out. */
2366 if (s->pid != 0)
2367 record_logout(s->pid, s->tty, s->pw->pw_name);
2368
2369 /* Release the pseudo-tty. */
2370 if (getuid() == 0)
2371 pty_release(s->tty);
2372
2373 /*
2374 * Close the server side of the socket pairs. We must do this after
2375 * the pty cleanup, so that another process doesn't get this pty
2376 * while we're still cleaning up.
2377 */
c8c467ee
PA
2378 if (s->ptymaster != -1 && close(s->ptymaster) < 0)
2379 error("close(s->ptymaster/%d): %s",
2380 s->ptymaster, strerror(errno));
16c343f1
PA
2381
2382 /* unlink pty from session */
2383 s->ttyfd = -1;
2384}
2385
2386void
2387session_pty_cleanup(Session *s)
2388{
2389 PRIVSEP(session_pty_cleanup2(s));
2390}
2391
2392static char *
2393sig2name(int sig)
2394{
2395#define SSH_SIG(x) if (sig == SIG ## x) return #x
2396 SSH_SIG(ABRT);
2397 SSH_SIG(ALRM);
2398 SSH_SIG(FPE);
2399 SSH_SIG(HUP);
2400 SSH_SIG(ILL);
2401 SSH_SIG(INT);
2402 SSH_SIG(KILL);
2403 SSH_SIG(PIPE);
2404 SSH_SIG(QUIT);
2405 SSH_SIG(SEGV);
2406 SSH_SIG(TERM);
2407 SSH_SIG(USR1);
2408 SSH_SIG(USR2);
2409#undef SSH_SIG
2410 return "SIG@openssh.com";
2411}
2412
2413static void
2414session_close_x11(int id)
2415{
2416 Channel *c;
2417
2418 if ((c = channel_by_id(id)) == NULL) {
2419 debug("session_close_x11: x11 channel %d missing", id);
2420 } else {
2421 /* Detach X11 listener */
2422 debug("session_close_x11: detach x11 channel %d", id);
2423 channel_cancel_cleanup(id);
2424 if (c->ostate != CHAN_OUTPUT_CLOSED)
2425 chan_mark_dead(c);
2426 }
2427}
2428
2429static void
2430session_close_single_x11(int id, void *arg)
2431{
2432 Session *s;
2433 u_int i;
2434
2435 debug3("session_close_single_x11: channel %d", id);
2436 channel_cancel_cleanup(id);
2437 if ((s = session_by_x11_channel(id)) == NULL)
2438 fatal("session_close_single_x11: no x11 channel %d", id);
2439 for (i = 0; s->x11_chanids[i] != -1; i++) {
2440 debug("session_close_single_x11: session %d: "
2441 "closing channel %d", s->self, s->x11_chanids[i]);
2442 /*
2443 * The channel "id" is already closing, but make sure we
2444 * close all of its siblings.
2445 */
2446 if (s->x11_chanids[i] != id)
2447 session_close_x11(s->x11_chanids[i]);
2448 }
2449 xfree(s->x11_chanids);
2450 s->x11_chanids = NULL;
2451 if (s->display) {
2452 xfree(s->display);
2453 s->display = NULL;
2454 }
2455 if (s->auth_proto) {
2456 xfree(s->auth_proto);
2457 s->auth_proto = NULL;
2458 }
2459 if (s->auth_data) {
2460 xfree(s->auth_data);
2461 s->auth_data = NULL;
2462 }
2463 if (s->auth_display) {
2464 xfree(s->auth_display);
2465 s->auth_display = NULL;
2466 }
2467}
2468
2469static void
2470session_exit_message(Session *s, int status)
2471{
2472 Channel *c;
2473
2474 if ((c = channel_lookup(s->chanid)) == NULL)
2475 fatal("session_exit_message: session %d: no channel %d",
2476 s->self, s->chanid);
2477 debug("session_exit_message: session %d channel %d pid %ld",
2478 s->self, s->chanid, (long)s->pid);
2479
2480 if (WIFEXITED(status)) {
2481 channel_request_start(s->chanid, "exit-status", 0);
2482 packet_put_int(WEXITSTATUS(status));
2483 packet_send();
2484 } else if (WIFSIGNALED(status)) {
2485 channel_request_start(s->chanid, "exit-signal", 0);
2486 packet_put_cstring(sig2name(WTERMSIG(status)));
2487#ifdef WCOREDUMP
2488 packet_put_char(WCOREDUMP(status)? 1 : 0);
2489#else /* WCOREDUMP */
2490 packet_put_char(0);
2491#endif /* WCOREDUMP */
2492 packet_put_cstring("");
2493 packet_put_cstring("");
2494 packet_send();
2495 } else {
2496 /* Some weird exit cause. Just exit. */
2497 packet_disconnect("wait returned status %04x.", status);
2498 }
2499
2500 /* disconnect channel */
2501 debug("session_exit_message: release channel %d", s->chanid);
2502
2503 /*
2504 * Adjust cleanup callback attachment to send close messages when
2505 * the channel gets EOF. The session will be then be closed
2506 * by session_close_by_channel when the childs close their fds.
2507 */
2508 channel_register_cleanup(c->self, session_close_by_channel, 1);
2509
2510 /*
2511 * emulate a write failure with 'chan_write_failed', nobody will be
2512 * interested in data we write.
2513 * Note that we must not call 'chan_read_failed', since there could
2514 * be some more data waiting in the pipe.
2515 */
2516 if (c->ostate != CHAN_OUTPUT_CLOSED)
2517 chan_write_failed(c);
2518}
2519
2520void
2521session_close(Session *s)
2522{
2523 u_int i;
2524
2525 debug("session_close: session %d pid %ld", s->self, (long)s->pid);
2526 if (s->ttyfd != -1)
2527 session_pty_cleanup(s);
2528 if (s->term)
2529 xfree(s->term);
2530 if (s->display)
2531 xfree(s->display);
2532 if (s->x11_chanids)
2533 xfree(s->x11_chanids);
2534 if (s->auth_display)
2535 xfree(s->auth_display);
2536 if (s->auth_data)
2537 xfree(s->auth_data);
2538 if (s->auth_proto)
2539 xfree(s->auth_proto);
16c343f1
PA
2540 if (s->env != NULL) {
2541 for (i = 0; i < s->num_env; i++) {
2542 xfree(s->env[i].name);
2543 xfree(s->env[i].val);
2544 }
2545 xfree(s->env);
2546 }
2547 session_proctitle(s);
c8c467ee 2548 session_unused(s->self);
16c343f1
PA
2549}
2550
2551void
2552session_close_by_pid(pid_t pid, int status)
2553{
2554 Session *s = session_by_pid(pid);
2555 if (s == NULL) {
2556 debug("session_close_by_pid: no session for pid %ld",
2557 (long)pid);
2558 return;
2559 }
2560 if (s->chanid != -1)
2561 session_exit_message(s, status);
2562 if (s->ttyfd != -1)
2563 session_pty_cleanup(s);
2564 s->pid = 0;
2565}
2566
2567/*
2568 * this is called when a channel dies before
2569 * the session 'child' itself dies
2570 */
2571void
2572session_close_by_channel(int id, void *arg)
2573{
2574 Session *s = session_by_channel(id);
2575 u_int i;
2576
2577 if (s == NULL) {
2578 debug("session_close_by_channel: no session for id %d", id);
2579 return;
2580 }
2581 debug("session_close_by_channel: channel %d child %ld",
2582 id, (long)s->pid);
2583 if (s->pid != 0) {
2584 debug("session_close_by_channel: channel %d: has child", id);
2585 /*
2586 * delay detach of session, but release pty, since
2587 * the fd's to the child are already closed
2588 */
2589 if (s->ttyfd != -1)
2590 session_pty_cleanup(s);
2591 return;
2592 }
2593 /* detach by removing callback */
2594 channel_cancel_cleanup(s->chanid);
2595
2596 /* Close any X11 listeners associated with this session */
2597 if (s->x11_chanids != NULL) {
2598 for (i = 0; s->x11_chanids[i] != -1; i++) {
2599 session_close_x11(s->x11_chanids[i]);
2600 s->x11_chanids[i] = -1;
2601 }
2602 }
2603
2604 s->chanid = -1;
2605 session_close(s);
2606}
2607
2608void
2609session_destroy_all(void (*closefunc)(Session *))
2610{
2611 int i;
c8c467ee 2612 for (i = 0; i < sessions_nalloc; i++) {
16c343f1
PA
2613 Session *s = &sessions[i];
2614 if (s->used) {
2615 if (closefunc != NULL)
2616 closefunc(s);
2617 else
2618 session_close(s);
2619 }
2620 }
2621}
2622
2623static char *
2624session_tty_list(void)
2625{
2626 static char buf[1024];
2627 int i;
2628 char *cp;
2629
2630 buf[0] = '\0';
c8c467ee 2631 for (i = 0; i < sessions_nalloc; i++) {
16c343f1
PA
2632 Session *s = &sessions[i];
2633 if (s->used && s->ttyfd != -1) {
2634
2635 if (strncmp(s->tty, "/dev/", 5) != 0) {
2636 cp = strrchr(s->tty, '/');
2637 cp = (cp == NULL) ? s->tty : cp + 1;
2638 } else
2639 cp = s->tty + 5;
2640
2641 if (buf[0] != '\0')
2642 strlcat(buf, ",", sizeof buf);
2643 strlcat(buf, cp, sizeof buf);
2644 }
2645 }
2646 if (buf[0] == '\0')
2647 strlcpy(buf, "notty", sizeof buf);
2648 return buf;
2649}
2650
2651void
2652session_proctitle(Session *s)
2653{
2654 if (s->pw == NULL)
2655 error("no user for session %d", s->self);
2656 else
2657 setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
2658}
2659
2660int
2661session_setup_x11fwd(Session *s)
2662{
2663 struct stat st;
2664 char display[512], auth_display[512];
2665 char hostname[MAXHOSTNAMELEN];
2666 u_int i;
2667
2668 if (no_x11_forwarding_flag) {
2669 packet_send_debug("X11 forwarding disabled in user configuration file.");
2670 return 0;
2671 }
2672 if (!options.x11_forwarding) {
2673 debug("X11 forwarding disabled in server configuration file.");
2674 return 0;
2675 }
2676 if (!options.xauth_location ||
2677 (stat(options.xauth_location, &st) == -1)) {
2678 packet_send_debug("No xauth program; cannot forward with spoofing.");
2679 return 0;
2680 }
2681 if (options.use_login) {
2682 packet_send_debug("X11 forwarding disabled; "
2683 "not compatible with UseLogin=yes.");
2684 return 0;
2685 }
2686 if (s->display != NULL) {
2687 debug("X11 display already set.");
2688 return 0;
2689 }
2690 if (x11_create_display_inet(options.x11_display_offset,
2691 options.x11_use_localhost, s->single_connection,
2692 &s->display_number, &s->x11_chanids) == -1) {
2693 debug("x11_create_display_inet failed.");
2694 return 0;
2695 }
2696 for (i = 0; s->x11_chanids[i] != -1; i++) {
2697 channel_register_cleanup(s->x11_chanids[i],
2698 session_close_single_x11, 0);
2699 }
2700
2701 /* Set up a suitable value for the DISPLAY variable. */
2702 if (gethostname(hostname, sizeof(hostname)) < 0)
2703 fatal("gethostname: %.100s", strerror(errno));
2704 /*
2705 * auth_display must be used as the displayname when the
2706 * authorization entry is added with xauth(1). This will be
2707 * different than the DISPLAY string for localhost displays.
2708 */
2709 if (options.x11_use_localhost) {
2710 snprintf(display, sizeof display, "localhost:%u.%u",
2711 s->display_number, s->screen);
2712 snprintf(auth_display, sizeof auth_display, "unix:%u.%u",
2713 s->display_number, s->screen);
2714 s->display = xstrdup(display);
2715 s->auth_display = xstrdup(auth_display);
2716 } else {
2717#ifdef IPADDR_IN_DISPLAY
2718 struct hostent *he;
2719 struct in_addr my_addr;
2720
2721 he = gethostbyname(hostname);
2722 if (he == NULL) {
2723 error("Can't get IP address for X11 DISPLAY.");
2724 packet_send_debug("Can't get IP address for X11 DISPLAY.");
2725 return 0;
2726 }
2727 memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr));
2728 snprintf(display, sizeof display, "%.50s:%u.%u", inet_ntoa(my_addr),
2729 s->display_number, s->screen);
2730#else
2731 snprintf(display, sizeof display, "%.400s:%u.%u", hostname,
2732 s->display_number, s->screen);
2733#endif
2734 s->display = xstrdup(display);
2735 s->auth_display = xstrdup(display);
2736 }
2737
2738 return 1;
2739}
2740
2741static void
2742do_authenticated2(Authctxt *authctxt)
2743{
2744 server_loop2(authctxt);
2745}
2746
2747void
2748do_cleanup(Authctxt *authctxt)
2749{
2750 static int called = 0;
2751
2752 debug("do_cleanup");
2753
2754 /* no cleanup if we're in the child for login shell */
2755 if (is_child)
2756 return;
2757
2758 /* avoid double cleanup */
2759 if (called)
2760 return;
2761 called = 1;
2762
2763 if (authctxt == NULL)
2764 return;
2765
2766#ifdef USE_PAM
2767 if (options.use_pam) {
2768 sshpam_cleanup();
2769 sshpam_thread_cleanup();
2770 }
2771#endif
2772
2773 if (!authctxt->authenticated)
2774 return;
2775
2776#ifdef KRB5
2777 if (options.kerberos_ticket_cleanup &&
2778 authctxt->krb5_ctx)
2779 krb5_cleanup_proc(authctxt);
2780#endif
2781
2782#ifdef GSSAPI
2783 if (compat20 && options.gss_cleanup_creds)
2784 ssh_gssapi_cleanup_creds();
2785#endif
2786
2787 /* remove agent socket */
2788 auth_sock_cleanup_proc(authctxt->pw);
2789
2790 /*
2791 * Cleanup ptys/utmp only if privsep is disabled,
2792 * or if running in monitor.
2793 */
2794 if (!use_privsep || mm_is_monitor())
2795 session_destroy_all(session_pty_cleanup2);
2796}