SSHD - Do not attempt to free environ or its contents
[dragonfly.git] / crypto / openssh / session.c
CommitLineData
cb5eb4f1 1/* $OpenBSD: session.c,v 1.245 2009/01/22 09:46:01 djm 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
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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. */
233 nc = channel_new("auth socket",
234 SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1,
235 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
236 0, "auth socket", 1);
cb5eb4f1 237 nc->path = xstrdup(auth_sock_name);
16c343f1 238 return 1;
c8c467ee
PA
239
240 authsock_err:
241 if (auth_sock_name != NULL)
242 xfree(auth_sock_name);
243 if (auth_sock_dir != NULL) {
244 rmdir(auth_sock_dir);
245 xfree(auth_sock_dir);
246 }
247 if (sock != -1)
248 close(sock);
249 auth_sock_name = NULL;
250 auth_sock_dir = NULL;
251 return 0;
16c343f1
PA
252}
253
254static void
255display_loginmsg(void)
256{
257 if (buffer_len(&loginmsg) > 0) {
258 buffer_append(&loginmsg, "\0", 1);
259 printf("%s", (char *)buffer_ptr(&loginmsg));
260 buffer_clear(&loginmsg);
261 }
262}
263
264void
265do_authenticated(Authctxt *authctxt)
266{
267 setproctitle("%s", authctxt->pw->pw_name);
268
269 /* setup the channel layer */
270 if (!no_port_forwarding_flag && options.allow_tcp_forwarding)
271 channel_permit_all_opens();
272
273 if (compat20)
274 do_authenticated2(authctxt);
275 else
276 do_authenticated1(authctxt);
277
278 do_cleanup(authctxt);
279}
280
281/*
282 * Prepares for an interactive session. This is called after the user has
283 * been successfully authenticated. During this message exchange, pseudo
284 * terminals are allocated, X11, TCP/IP, and authentication agent forwardings
285 * are requested, etc.
286 */
287static void
288do_authenticated1(Authctxt *authctxt)
289{
290 Session *s;
291 char *command;
292 int success, type, screen_flag;
293 int enable_compression_after_reply = 0;
294 u_int proto_len, data_len, dlen, compression_level = 0;
295
296 s = session_new();
297 if (s == NULL) {
298 error("no more sessions");
299 return;
300 }
301 s->authctxt = authctxt;
302 s->pw = authctxt->pw;
303
304 /*
305 * We stay in this loop until the client requests to execute a shell
306 * or a command.
307 */
308 for (;;) {
309 success = 0;
310
311 /* Get a packet from the client. */
312 type = packet_read();
313
314 /* Process the packet. */
315 switch (type) {
316 case SSH_CMSG_REQUEST_COMPRESSION:
317 compression_level = packet_get_int();
318 packet_check_eom();
319 if (compression_level < 1 || compression_level > 9) {
320 packet_send_debug("Received invalid compression level %d.",
321 compression_level);
322 break;
323 }
324 if (options.compression == COMP_NONE) {
325 debug2("compression disabled");
326 break;
327 }
328 /* Enable compression after we have responded with SUCCESS. */
329 enable_compression_after_reply = 1;
330 success = 1;
331 break;
332
333 case SSH_CMSG_REQUEST_PTY:
334 success = session_pty_req(s);
335 break;
336
337 case SSH_CMSG_X11_REQUEST_FORWARDING:
338 s->auth_proto = packet_get_string(&proto_len);
339 s->auth_data = packet_get_string(&data_len);
340
341 screen_flag = packet_get_protocol_flags() &
342 SSH_PROTOFLAG_SCREEN_NUMBER;
343 debug2("SSH_PROTOFLAG_SCREEN_NUMBER: %d", screen_flag);
344
345 if (packet_remaining() == 4) {
346 if (!screen_flag)
347 debug2("Buggy client: "
348 "X11 screen flag missing");
349 s->screen = packet_get_int();
350 } else {
351 s->screen = 0;
352 }
353 packet_check_eom();
354 success = session_setup_x11fwd(s);
355 if (!success) {
356 xfree(s->auth_proto);
357 xfree(s->auth_data);
358 s->auth_proto = NULL;
359 s->auth_data = NULL;
360 }
361 break;
362
363 case SSH_CMSG_AGENT_REQUEST_FORWARDING:
c8c467ee
PA
364 if (!options.allow_agent_forwarding ||
365 no_agent_forwarding_flag || compat13) {
16c343f1
PA
366 debug("Authentication agent forwarding not permitted for this authentication.");
367 break;
368 }
369 debug("Received authentication agent forwarding request.");
370 success = auth_input_request_forwarding(s->pw);
371 break;
372
373 case SSH_CMSG_PORT_FORWARD_REQUEST:
374 if (no_port_forwarding_flag) {
375 debug("Port forwarding not permitted for this authentication.");
376 break;
377 }
378 if (!options.allow_tcp_forwarding) {
379 debug("Port forwarding not permitted.");
380 break;
381 }
382 debug("Received TCP/IP port forwarding request.");
383 if (channel_input_port_forward_request(s->pw->pw_uid == 0,
384 options.gateway_ports) < 0) {
385 debug("Port forwarding failed.");
386 break;
387 }
388 success = 1;
389 break;
390
391 case SSH_CMSG_MAX_PACKET_SIZE:
392 if (packet_set_maxsize(packet_get_int()) > 0)
393 success = 1;
394 break;
395
396 case SSH_CMSG_EXEC_SHELL:
397 case SSH_CMSG_EXEC_CMD:
398 if (type == SSH_CMSG_EXEC_CMD) {
399 command = packet_get_string(&dlen);
400 debug("Exec command '%.500s'", command);
c8c467ee
PA
401 if (do_exec(s, command) != 0)
402 packet_disconnect(
403 "command execution failed");
16c343f1
PA
404 xfree(command);
405 } else {
c8c467ee
PA
406 if (do_exec(s, NULL) != 0)
407 packet_disconnect(
408 "shell execution failed");
16c343f1
PA
409 }
410 packet_check_eom();
411 session_close(s);
412 return;
413
414 default:
415 /*
416 * Any unknown messages in this phase are ignored,
417 * and a failure message is returned.
418 */
419 logit("Unknown packet type received after authentication: %d", type);
420 }
421 packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE);
422 packet_send();
423 packet_write_wait();
424
425 /* Enable compression now that we have replied if appropriate. */
426 if (enable_compression_after_reply) {
427 enable_compression_after_reply = 0;
428 packet_start_compression(compression_level);
429 }
430 }
431}
432
c8c467ee 433#define USE_PIPES
16c343f1
PA
434/*
435 * This is called to fork and execute a command when we have no tty. This
436 * will call do_child from the child, and server_loop from the parent after
437 * setting up file descriptors and such.
438 */
c8c467ee 439int
16c343f1
PA
440do_exec_no_pty(Session *s, const char *command)
441{
442 pid_t pid;
443
444#ifdef USE_PIPES
445 int pin[2], pout[2], perr[2];
c8c467ee 446
16c343f1 447 /* Allocate pipes for communicating with the program. */
c8c467ee
PA
448 if (pipe(pin) < 0) {
449 error("%s: pipe in: %.100s", __func__, strerror(errno));
450 return -1;
451 }
452 if (pipe(pout) < 0) {
453 error("%s: pipe out: %.100s", __func__, strerror(errno));
454 close(pin[0]);
455 close(pin[1]);
456 return -1;
457 }
458 if (pipe(perr) < 0) {
459 error("%s: pipe err: %.100s", __func__, strerror(errno));
460 close(pin[0]);
461 close(pin[1]);
462 close(pout[0]);
463 close(pout[1]);
464 return -1;
465 }
466#else
16c343f1 467 int inout[2], err[2];
c8c467ee 468
16c343f1 469 /* Uses socket pairs to communicate with the program. */
c8c467ee
PA
470 if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0) {
471 error("%s: socketpair #1: %.100s", __func__, strerror(errno));
472 return -1;
473 }
474 if (socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0) {
475 error("%s: socketpair #2: %.100s", __func__, strerror(errno));
476 close(inout[0]);
477 close(inout[1]);
478 return -1;
479 }
480#endif
481
16c343f1
PA
482 if (s == NULL)
483 fatal("do_exec_no_pty: no session");
484
485 session_proctitle(s);
486
487 /* Fork the child. */
c8c467ee
PA
488 switch ((pid = fork())) {
489 case -1:
490 error("%s: fork: %.100s", __func__, strerror(errno));
491#ifdef USE_PIPES
492 close(pin[0]);
493 close(pin[1]);
494 close(pout[0]);
495 close(pout[1]);
496 close(perr[0]);
497 close(perr[1]);
498#else
499 close(inout[0]);
500 close(inout[1]);
501 close(err[0]);
502 close(err[1]);
503#endif
504 return -1;
505 case 0:
16c343f1
PA
506 is_child = 1;
507
508 /* Child. Reinitialize the log since the pid has changed. */
c8c467ee
PA
509 log_init(__progname, options.log_level,
510 options.log_facility, log_stderr);
16c343f1
PA
511
512 /*
513 * Create a new session and process group since the 4.4BSD
514 * setlogin() affects the entire process group.
515 */
516 if (setsid() < 0)
517 error("setsid failed: %.100s", strerror(errno));
518
519#ifdef USE_PIPES
520 /*
521 * Redirect stdin. We close the parent side of the socket
522 * pair, and make the child side the standard input.
523 */
524 close(pin[1]);
525 if (dup2(pin[0], 0) < 0)
526 perror("dup2 stdin");
527 close(pin[0]);
528
529 /* Redirect stdout. */
530 close(pout[0]);
531 if (dup2(pout[1], 1) < 0)
532 perror("dup2 stdout");
533 close(pout[1]);
534
535 /* Redirect stderr. */
536 close(perr[0]);
537 if (dup2(perr[1], 2) < 0)
538 perror("dup2 stderr");
539 close(perr[1]);
c8c467ee 540#else
16c343f1
PA
541 /*
542 * Redirect stdin, stdout, and stderr. Stdin and stdout will
543 * use the same socket, as some programs (particularly rdist)
544 * seem to depend on it.
545 */
546 close(inout[1]);
547 close(err[1]);
548 if (dup2(inout[0], 0) < 0) /* stdin */
549 perror("dup2 stdin");
c8c467ee 550 if (dup2(inout[0], 1) < 0) /* stdout (same as stdin) */
16c343f1 551 perror("dup2 stdout");
c8c467ee 552 close(inout[0]);
16c343f1
PA
553 if (dup2(err[0], 2) < 0) /* stderr */
554 perror("dup2 stderr");
c8c467ee
PA
555 close(err[0]);
556#endif
557
16c343f1
PA
558
559#ifdef _UNICOS
560 cray_init_job(s->pw); /* set up cray jid and tmpdir */
561#endif
562
563 /* Do processing for the child (exec command etc). */
564 do_child(s, command);
565 /* NOTREACHED */
c8c467ee
PA
566 default:
567 break;
16c343f1 568 }
c8c467ee 569
16c343f1
PA
570#ifdef _UNICOS
571 signal(WJSIGNAL, cray_job_termination_handler);
572#endif /* _UNICOS */
573#ifdef HAVE_CYGWIN
574 if (is_winnt)
575 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
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
611 /*
16c343f1
PA
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 */
719 do_child(s, command);
720 /* NOTREACHED */
721 default:
722 break;
16c343f1 723 }
c8c467ee 724
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PA
725#ifdef _UNICOS
726 signal(WJSIGNAL, cray_job_termination_handler);
727#endif /* _UNICOS */
728#ifdef HAVE_CYGWIN
729 if (is_winnt)
730 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
731#endif
c8c467ee 732
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PA
733 s->pid = pid;
734
735 /* Parent. Close the slave side of the pseudo tty. */
736 close(ttyfd);
737
16c343f1 738 /* Enter interactive session. */
c8c467ee 739 s->ptymaster = ptymaster;
16c343f1
PA
740 packet_set_interactive(1);
741 if (compat20) {
c8c467ee 742 session_set_fds(s, ptyfd, fdout, -1, 1);
16c343f1
PA
743 } else {
744 server_loop(pid, ptyfd, fdout, -1);
745 /* server_loop _has_ closed ptyfd and fdout. */
746 }
c8c467ee 747 return 0;
16c343f1
PA
748}
749
750#ifdef LOGIN_NEEDS_UTMPX
751static void
752do_pre_login(Session *s)
753{
754 socklen_t fromlen;
755 struct sockaddr_storage from;
756 pid_t pid = getpid();
757
758 /*
759 * Get IP address of client. If the connection is not a socket, let
760 * the address be 0.0.0.0.
761 */
762 memset(&from, 0, sizeof(from));
763 fromlen = sizeof(from);
764 if (packet_connection_is_on_socket()) {
765 if (getpeername(packet_get_connection_in(),
766 (struct sockaddr *)&from, &fromlen) < 0) {
767 debug("getpeername: %.100s", strerror(errno));
768 cleanup_exit(255);
769 }
770 }
771
772 record_utmp_only(pid, s->tty, s->pw->pw_name,
773 get_remote_name_or_ip(utmp_len, options.use_dns),
774 (struct sockaddr *)&from, fromlen);
775}
776#endif
777
778/*
779 * This is called to fork and execute a command. If another command is
780 * to be forced, execute that instead.
781 */
c8c467ee 782int
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783do_exec(Session *s, const char *command)
784{
c8c467ee
PA
785 int ret;
786
16c343f1
PA
787 if (options.adm_forced_command) {
788 original_command = command;
789 command = options.adm_forced_command;
cb5eb4f1 790 if (IS_INTERNAL_SFTP(command))
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PA
791 s->is_subsystem = SUBSYSTEM_INT_SFTP;
792 else if (s->is_subsystem)
793 s->is_subsystem = SUBSYSTEM_EXT;
794 debug("Forced command (config) '%.900s'", command);
795 } else if (forced_command) {
796 original_command = command;
797 command = forced_command;
cb5eb4f1 798 if (IS_INTERNAL_SFTP(command))
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PA
799 s->is_subsystem = SUBSYSTEM_INT_SFTP;
800 else if (s->is_subsystem)
801 s->is_subsystem = SUBSYSTEM_EXT;
802 debug("Forced command (key option) '%.900s'", command);
803 }
804
805#ifdef SSH_AUDIT_EVENTS
806 if (command != NULL)
807 PRIVSEP(audit_run_command(command));
808 else if (s->ttyfd == -1) {
809 char *shell = s->pw->pw_shell;
810
811 if (shell[0] == '\0') /* empty shell means /bin/sh */
812 shell =_PATH_BSHELL;
813 PRIVSEP(audit_run_command(shell));
814 }
815#endif
816 if (s->ttyfd != -1)
c8c467ee 817 ret = do_exec_pty(s, command);
16c343f1 818 else
c8c467ee 819 ret = do_exec_no_pty(s, command);
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PA
820
821 original_command = NULL;
822
823 /*
824 * Clear loginmsg: it's the child's responsibility to display
825 * it to the user, otherwise multiple sessions may accumulate
826 * multiple copies of the login messages.
827 */
828 buffer_clear(&loginmsg);
c8c467ee
PA
829
830 return ret;
16c343f1
PA
831}
832
833/* administrative, login(1)-like work */
834void
835do_login(Session *s, const char *command)
836{
837 socklen_t fromlen;
838 struct sockaddr_storage from;
839 struct passwd * pw = s->pw;
840 pid_t pid = getpid();
841
842 /*
843 * Get IP address of client. If the connection is not a socket, let
844 * the address be 0.0.0.0.
845 */
846 memset(&from, 0, sizeof(from));
847 fromlen = sizeof(from);
848 if (packet_connection_is_on_socket()) {
849 if (getpeername(packet_get_connection_in(),
850 (struct sockaddr *) & from, &fromlen) < 0) {
851 debug("getpeername: %.100s", strerror(errno));
852 cleanup_exit(255);
853 }
854 }
855
856 /* Record that there was a login on that tty from the remote host. */
857 if (!use_privsep)
858 record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
859 get_remote_name_or_ip(utmp_len,
860 options.use_dns),
861 (struct sockaddr *)&from, fromlen);
862
863#ifdef USE_PAM
864 /*
865 * If password change is needed, do it now.
866 * This needs to occur before the ~/.hushlogin check.
867 */
868 if (options.use_pam && !use_privsep && s->authctxt->force_pwchange) {
869 display_loginmsg();
870 do_pam_chauthtok();
871 s->authctxt->force_pwchange = 0;
872 /* XXX - signal [net] parent to enable forwardings */
873 }
874#endif
875
876 if (check_quietlogin(s, command))
877 return;
878
879 display_loginmsg();
880
881 do_motd();
882}
883
884/*
885 * Display the message of the day.
886 */
887void
888do_motd(void)
889{
890 FILE *f;
891 char buf[256];
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PA
892#ifdef HAVE_LOGIN_CAP
893 const char *fname;
894#endif
895
896#ifdef HAVE_LOGIN_CAP
897 fname = login_getcapstr(lc, "copyright", NULL, NULL);
898 if (fname != NULL && (f = fopen(fname, "r")) != NULL) {
899 while (fgets(buf, sizeof(buf), f) != NULL)
900 fputs(buf, stdout);
901 fclose(f);
902 } else
903#endif /* HAVE_LOGIN_CAP */
904 (void)printf("%s\n\t%s %s\n",
905 "Copyright (c) 1980, 1983, 1986, 1988, 1990, 1991, 1993, 1994",
906 "The Regents of the University of California. ",
907 "All rights reserved.");
908
909 (void)printf("\n");
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PA
910
911 if (options.print_motd) {
912#ifdef HAVE_LOGIN_CAP
913 f = fopen(login_getcapstr(lc, "welcome", "/etc/motd",
914 "/etc/motd"), "r");
915#else
916 f = fopen("/etc/motd", "r");
917#endif
918 if (f) {
919 while (fgets(buf, sizeof(buf), f))
920 fputs(buf, stdout);
921 fclose(f);
922 }
923 }
924}
925
926
927/*
928 * Check for quiet login, either .hushlogin or command given.
929 */
930int
931check_quietlogin(Session *s, const char *command)
932{
933 char buf[256];
934 struct passwd *pw = s->pw;
935 struct stat st;
936
937 /* Return 1 if .hushlogin exists or a command given. */
938 if (command != NULL)
939 return 1;
940 snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
941#ifdef HAVE_LOGIN_CAP
942 if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
943 return 1;
944#else
945 if (stat(buf, &st) >= 0)
946 return 1;
947#endif
948 return 0;
949}
950
951/*
952 * Sets the value of the given variable in the environment. If the variable
cb5eb4f1 953 * already exists, its value is overridden.
16c343f1
PA
954 */
955void
956child_set_env(char ***envp, u_int *envsizep, const char *name,
957 const char *value)
958{
959 char **env;
960 u_int envsize;
961 u_int i, namelen;
962
963 /*
964 * If we're passed an uninitialized list, allocate a single null
965 * entry before continuing.
966 */
967 if (*envp == NULL && *envsizep == 0) {
968 *envp = xmalloc(sizeof(char *));
969 *envp[0] = NULL;
970 *envsizep = 1;
971 }
972
973 /*
974 * Find the slot where the value should be stored. If the variable
975 * already exists, we reuse the slot; otherwise we append a new slot
976 * at the end of the array, expanding if necessary.
977 */
978 env = *envp;
979 namelen = strlen(name);
980 for (i = 0; env[i]; i++)
981 if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
982 break;
983 if (env[i]) {
984 /* Reuse the slot. */
985 xfree(env[i]);
986 } else {
987 /* New variable. Expand if necessary. */
988 envsize = *envsizep;
989 if (i >= envsize - 1) {
990 if (envsize >= 1000)
991 fatal("child_set_env: too many env vars");
992 envsize += 50;
993 env = (*envp) = xrealloc(env, envsize, sizeof(char *));
994 *envsizep = envsize;
995 }
996 /* Need to set the NULL pointer at end of array beyond the new slot. */
997 env[i + 1] = NULL;
998 }
999
1000 /* Allocate space and format the variable in the appropriate slot. */
1001 env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
1002 snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
1003}
1004
1005/*
1006 * Reads environment variables from the given file and adds/overrides them
1007 * into the environment. If the file does not exist, this does nothing.
1008 * Otherwise, it must consist of empty lines, comments (line starts with '#')
1009 * and assignments of the form name=value. No other forms are allowed.
1010 */
1011static void
1012read_environment_file(char ***env, u_int *envsize,
1013 const char *filename)
1014{
1015 FILE *f;
1016 char buf[4096];
1017 char *cp, *value;
1018 u_int lineno = 0;
1019
1020 f = fopen(filename, "r");
1021 if (!f)
1022 return;
1023
1024 while (fgets(buf, sizeof(buf), f)) {
1025 if (++lineno > 1000)
1026 fatal("Too many lines in environment file %s", filename);
1027 for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
1028 ;
1029 if (!*cp || *cp == '#' || *cp == '\n')
1030 continue;
1031
1032 cp[strcspn(cp, "\n")] = '\0';
1033
1034 value = strchr(cp, '=');
1035 if (value == NULL) {
1036 fprintf(stderr, "Bad line %u in %.100s\n", lineno,
1037 filename);
1038 continue;
1039 }
1040 /*
1041 * Replace the equals sign by nul, and advance value to
1042 * the value string.
1043 */
1044 *value = '\0';
1045 value++;
1046 child_set_env(env, envsize, cp, value);
1047 }
1048 fclose(f);
1049}
1050
1051#ifdef HAVE_ETC_DEFAULT_LOGIN
1052/*
1053 * Return named variable from specified environment, or NULL if not present.
1054 */
1055static char *
1056child_get_env(char **env, const char *name)
1057{
1058 int i;
1059 size_t len;
1060
1061 len = strlen(name);
1062 for (i=0; env[i] != NULL; i++)
1063 if (strncmp(name, env[i], len) == 0 && env[i][len] == '=')
1064 return(env[i] + len + 1);
1065 return NULL;
1066}
1067
1068/*
1069 * Read /etc/default/login.
1070 * We pick up the PATH (or SUPATH for root) and UMASK.
1071 */
1072static void
1073read_etc_default_login(char ***env, u_int *envsize, uid_t uid)
1074{
1075 char **tmpenv = NULL, *var;
1076 u_int i, tmpenvsize = 0;
1077 u_long mask;
1078
1079 /*
1080 * We don't want to copy the whole file to the child's environment,
1081 * so we use a temporary environment and copy the variables we're
1082 * interested in.
1083 */
1084 read_environment_file(&tmpenv, &tmpenvsize, "/etc/default/login");
1085
1086 if (tmpenv == NULL)
1087 return;
1088
1089 if (uid == 0)
1090 var = child_get_env(tmpenv, "SUPATH");
1091 else
1092 var = child_get_env(tmpenv, "PATH");
1093 if (var != NULL)
1094 child_set_env(env, envsize, "PATH", var);
1095
1096 if ((var = child_get_env(tmpenv, "UMASK")) != NULL)
1097 if (sscanf(var, "%5lo", &mask) == 1)
1098 umask((mode_t)mask);
1099
1100 for (i = 0; tmpenv[i] != NULL; i++)
1101 xfree(tmpenv[i]);
1102 xfree(tmpenv);
1103}
1104#endif /* HAVE_ETC_DEFAULT_LOGIN */
1105
1106void
1107copy_environment(char **source, char ***env, u_int *envsize)
1108{
1109 char *var_name, *var_val;
1110 int i;
1111
1112 if (source == NULL)
1113 return;
1114
1115 for(i = 0; source[i] != NULL; i++) {
1116 var_name = xstrdup(source[i]);
1117 if ((var_val = strstr(var_name, "=")) == NULL) {
1118 xfree(var_name);
1119 continue;
1120 }
1121 *var_val++ = '\0';
1122
1123 debug3("Copy environment: %s=%s", var_name, var_val);
1124 child_set_env(env, envsize, var_name, var_val);
1125
1126 xfree(var_name);
1127 }
1128}
1129
1130static char **
1131do_setup_env(Session *s, const char *shell)
1132{
1133 char buf[256];
1134 u_int i, envsize;
1135 char **env, *laddr;
1136 struct passwd *pw = s->pw;
1137#ifndef HAVE_LOGIN_CAP
1138 char *path = NULL;
40948e2d
PA
1139#else
1140 extern char **environ;
1141 char **senv, **var;
16c343f1
PA
1142#endif
1143
1144 /* Initialize the environment. */
1145 envsize = 100;
1146 env = xcalloc(envsize, sizeof(char *));
1147 env[0] = NULL;
1148
1149#ifdef HAVE_CYGWIN
1150 /*
1151 * The Windows environment contains some setting which are
1152 * important for a running system. They must not be dropped.
1153 */
1154 {
1155 char **p;
1156
1157 p = fetch_windows_environment();
1158 copy_environment(p, &env, &envsize);
1159 free_windows_environment(p);
1160 }
1161#endif
1162
40948e2d
PA
1163 if (getenv("TZ"))
1164 child_set_env(&env, &envsize, "TZ", getenv("TZ"));
1165
16c343f1
PA
1166#ifdef GSSAPI
1167 /* Allow any GSSAPI methods that we've used to alter
1168 * the childs environment as they see fit
1169 */
1170 ssh_gssapi_do_child(&env, &envsize);
1171#endif
1172
1173 if (!options.use_login) {
1174 /* Set basic environment. */
1175 for (i = 0; i < s->num_env; i++)
1176 child_set_env(&env, &envsize, s->env[i].name,
1177 s->env[i].val);
1178
1179 child_set_env(&env, &envsize, "USER", pw->pw_name);
1180 child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
1181#ifdef _AIX
1182 child_set_env(&env, &envsize, "LOGIN", pw->pw_name);
1183#endif
1184 child_set_env(&env, &envsize, "HOME", pw->pw_dir);
40948e2d
PA
1185 snprintf(buf, sizeof buf, "%.200s/%.50s",
1186 _PATH_MAILDIR, pw->pw_name);
1187 child_set_env(&env, &envsize, "MAIL", buf);
16c343f1 1188#ifdef HAVE_LOGIN_CAP
40948e2d
PA
1189 child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
1190 child_set_env(&env, &envsize, "TERM", "su");
1191 senv = environ;
1192 environ = xmalloc(sizeof(char *));
1193 *environ = NULL;
1194 (void) setusercontext(lc, pw, pw->pw_uid,
1195 LOGIN_SETENV|LOGIN_SETPATH);
1196 copy_environment(environ, &env, &envsize);
5f3ddf32
MD
1197#if 0
1198 /*
1199 * This interferes with libc's management of the environment
1200 * in horrible ways that can cause sshd to crash.
1201 */
40948e2d
PA
1202 for (var = environ; *var != NULL; ++var)
1203 xfree(*var);
1204 xfree(environ);
5f3ddf32 1205#endif
40948e2d 1206 environ = senv;
16c343f1
PA
1207#else /* HAVE_LOGIN_CAP */
1208# ifndef HAVE_CYGWIN
1209 /*
1210 * There's no standard path on Windows. The path contains
1211 * important components pointing to the system directories,
1212 * needed for loading shared libraries. So the path better
1213 * remains intact here.
1214 */
1215# ifdef HAVE_ETC_DEFAULT_LOGIN
1216 read_etc_default_login(&env, &envsize, pw->pw_uid);
1217 path = child_get_env(env, "PATH");
1218# endif /* HAVE_ETC_DEFAULT_LOGIN */
1219 if (path == NULL || *path == '\0') {
1220 child_set_env(&env, &envsize, "PATH",
1221 s->pw->pw_uid == 0 ?
1222 SUPERUSER_PATH : _PATH_STDPATH);
1223 }
1224# endif /* HAVE_CYGWIN */
1225#endif /* HAVE_LOGIN_CAP */
1226
16c343f1
PA
1227 /* Normal systems set SHELL by default. */
1228 child_set_env(&env, &envsize, "SHELL", shell);
1229 }
16c343f1
PA
1230
1231 /* Set custom environment options from RSA authentication. */
1232 if (!options.use_login) {
1233 while (custom_environment) {
1234 struct envstring *ce = custom_environment;
1235 char *str = ce->s;
1236
1237 for (i = 0; str[i] != '=' && str[i]; i++)
1238 ;
1239 if (str[i] == '=') {
1240 str[i] = 0;
1241 child_set_env(&env, &envsize, str, str + i + 1);
1242 }
1243 custom_environment = ce->next;
1244 xfree(ce->s);
1245 xfree(ce);
1246 }
1247 }
1248
1249 /* SSH_CLIENT deprecated */
1250 snprintf(buf, sizeof buf, "%.50s %d %d",
1251 get_remote_ipaddr(), get_remote_port(), get_local_port());
1252 child_set_env(&env, &envsize, "SSH_CLIENT", buf);
1253
1254 laddr = get_local_ipaddr(packet_get_connection_in());
1255 snprintf(buf, sizeof buf, "%.50s %d %.50s %d",
1256 get_remote_ipaddr(), get_remote_port(), laddr, get_local_port());
1257 xfree(laddr);
1258 child_set_env(&env, &envsize, "SSH_CONNECTION", buf);
1259
1260 if (s->ttyfd != -1)
1261 child_set_env(&env, &envsize, "SSH_TTY", s->tty);
1262 if (s->term)
1263 child_set_env(&env, &envsize, "TERM", s->term);
1264 if (s->display)
1265 child_set_env(&env, &envsize, "DISPLAY", s->display);
1266 if (original_command)
1267 child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
1268 original_command);
1269
1270#ifdef _UNICOS
1271 if (cray_tmpdir[0] != '\0')
1272 child_set_env(&env, &envsize, "TMPDIR", cray_tmpdir);
1273#endif /* _UNICOS */
1274
1275 /*
1276 * Since we clear KRB5CCNAME at startup, if it's set now then it
1277 * must have been set by a native authentication method (eg AIX or
1278 * SIA), so copy it to the child.
1279 */
1280 {
1281 char *cp;
1282
1283 if ((cp = getenv("KRB5CCNAME")) != NULL)
1284 child_set_env(&env, &envsize, "KRB5CCNAME", cp);
1285 }
1286
1287#ifdef _AIX
1288 {
1289 char *cp;
1290
1291 if ((cp = getenv("AUTHSTATE")) != NULL)
1292 child_set_env(&env, &envsize, "AUTHSTATE", cp);
1293 read_environment_file(&env, &envsize, "/etc/environment");
1294 }
1295#endif
1296#ifdef KRB5
1297 if (s->authctxt->krb5_ccname)
1298 child_set_env(&env, &envsize, "KRB5CCNAME",
1299 s->authctxt->krb5_ccname);
1300#endif
1301#ifdef USE_PAM
1302 /*
1303 * Pull in any environment variables that may have
1304 * been set by PAM.
1305 */
1306 if (options.use_pam) {
1307 char **p;
1308
1309 p = fetch_pam_child_environment();
1310 copy_environment(p, &env, &envsize);
1311 free_pam_environment(p);
1312
1313 p = fetch_pam_environment();
1314 copy_environment(p, &env, &envsize);
1315 free_pam_environment(p);
1316 }
1317#endif /* USE_PAM */
1318
1319 if (auth_sock_name != NULL)
1320 child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
1321 auth_sock_name);
1322
1323 /* read $HOME/.ssh/environment. */
1324 if (options.permit_user_env && !options.use_login) {
1325 snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
1326 strcmp(pw->pw_dir, "/") ? pw->pw_dir : "");
1327 read_environment_file(&env, &envsize, buf);
1328 }
1329 if (debug_flag) {
1330 /* dump the environment */
1331 fprintf(stderr, "Environment:\n");
1332 for (i = 0; env[i]; i++)
1333 fprintf(stderr, " %.200s\n", env[i]);
1334 }
1335 return env;
1336}
1337
1338/*
1339 * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found
1340 * first in this order).
1341 */
1342static void
1343do_rc_files(Session *s, const char *shell)
1344{
1345 FILE *f = NULL;
1346 char cmd[1024];
1347 int do_xauth;
1348 struct stat st;
1349
1350 do_xauth =
1351 s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
1352
1353 /* ignore _PATH_SSH_USER_RC for subsystems and admin forced commands */
1354 if (!s->is_subsystem && options.adm_forced_command == NULL &&
c8c467ee 1355 !no_user_rc && stat(_PATH_SSH_USER_RC, &st) >= 0) {
16c343f1
PA
1356 snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
1357 shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
1358 if (debug_flag)
1359 fprintf(stderr, "Running %s\n", cmd);
1360 f = popen(cmd, "w");
1361 if (f) {
1362 if (do_xauth)
1363 fprintf(f, "%s %s\n", s->auth_proto,
1364 s->auth_data);
1365 pclose(f);
1366 } else
1367 fprintf(stderr, "Could not run %s\n",
1368 _PATH_SSH_USER_RC);
1369 } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
1370 if (debug_flag)
1371 fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
1372 _PATH_SSH_SYSTEM_RC);
1373 f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
1374 if (f) {
1375 if (do_xauth)
1376 fprintf(f, "%s %s\n", s->auth_proto,
1377 s->auth_data);
1378 pclose(f);
1379 } else
1380 fprintf(stderr, "Could not run %s\n",
1381 _PATH_SSH_SYSTEM_RC);
1382 } else if (do_xauth && options.xauth_location != NULL) {
1383 /* Add authority data to .Xauthority if appropriate. */
1384 if (debug_flag) {
1385 fprintf(stderr,
1386 "Running %.500s remove %.100s\n",
1387 options.xauth_location, s->auth_display);
1388 fprintf(stderr,
1389 "%.500s add %.100s %.100s %.100s\n",
1390 options.xauth_location, s->auth_display,
1391 s->auth_proto, s->auth_data);
1392 }
1393 snprintf(cmd, sizeof cmd, "%s -q -",
1394 options.xauth_location);
1395 f = popen(cmd, "w");
1396 if (f) {
1397 fprintf(f, "remove %s\n",
1398 s->auth_display);
1399 fprintf(f, "add %s %s %s\n",
1400 s->auth_display, s->auth_proto,
1401 s->auth_data);
1402 pclose(f);
1403 } else {
1404 fprintf(stderr, "Could not run %s\n",
1405 cmd);
1406 }
1407 }
1408}
1409
1410static void
1411do_nologin(struct passwd *pw)
1412{
1413 FILE *f = NULL;
1414 char buf[1024];
1415
1416#ifdef HAVE_LOGIN_CAP
1417 if (!login_getcapbool(lc, "ignorenologin", 0) && pw->pw_uid)
1418 f = fopen(login_getcapstr(lc, "nologin", _PATH_NOLOGIN,
1419 _PATH_NOLOGIN), "r");
1420#else
1421 if (pw->pw_uid)
1422 f = fopen(_PATH_NOLOGIN, "r");
1423#endif
1424 if (f) {
1425 /* /etc/nologin exists. Print its contents and exit. */
1426 logit("User %.100s not allowed because %s exists",
1427 pw->pw_name, _PATH_NOLOGIN);
1428 while (fgets(buf, sizeof(buf), f))
1429 fputs(buf, stderr);
1430 fclose(f);
1431 fflush(NULL);
1432 exit(254);
1433 }
1434}
1435
1436/*
1437 * Chroot into a directory after checking it for safety: all path components
1438 * must be root-owned directories with strict permissions.
1439 */
1440static void
1441safely_chroot(const char *path, uid_t uid)
1442{
1443 const char *cp;
1444 char component[MAXPATHLEN];
1445 struct stat st;
1446
1447 if (*path != '/')
1448 fatal("chroot path does not begin at root");
1449 if (strlen(path) >= sizeof(component))
1450 fatal("chroot path too long");
1451
1452 /*
1453 * Descend the path, checking that each component is a
1454 * root-owned directory with strict permissions.
1455 */
1456 for (cp = path; cp != NULL;) {
1457 if ((cp = strchr(cp, '/')) == NULL)
1458 strlcpy(component, path, sizeof(component));
1459 else {
1460 cp++;
1461 memcpy(component, path, cp - path);
1462 component[cp - path] = '\0';
1463 }
1464
1465 debug3("%s: checking '%s'", __func__, component);
1466
1467 if (stat(component, &st) != 0)
1468 fatal("%s: stat(\"%s\"): %s", __func__,
1469 component, strerror(errno));
1470 if (st.st_uid != 0 || (st.st_mode & 022) != 0)
1471 fatal("bad ownership or modes for chroot "
1472 "directory %s\"%s\"",
1473 cp == NULL ? "" : "component ", component);
1474 if (!S_ISDIR(st.st_mode))
1475 fatal("chroot path %s\"%s\" is not a directory",
1476 cp == NULL ? "" : "component ", component);
1477
1478 }
1479
1480 if (chdir(path) == -1)
1481 fatal("Unable to chdir to chroot path \"%s\": "
1482 "%s", path, strerror(errno));
1483 if (chroot(path) == -1)
1484 fatal("chroot(\"%s\"): %s", path, strerror(errno));
1485 if (chdir("/") == -1)
1486 fatal("%s: chdir(/) after chroot: %s",
1487 __func__, strerror(errno));
1488 verbose("Changed root directory to \"%s\"", path);
1489}
1490
1491/* Set login name, uid, gid, and groups. */
1492void
1493do_setusercontext(struct passwd *pw)
1494{
1495 char *chroot_path, *tmp;
1496
1497#ifdef WITH_SELINUX
1498 /* Cache selinux status for later use */
1499 (void)ssh_selinux_enabled();
1500#endif
1501
1502#ifndef HAVE_CYGWIN
1503 if (getuid() == 0 || geteuid() == 0)
1504#endif /* HAVE_CYGWIN */
1505 {
1506
1507#ifdef HAVE_SETPCRED
1508 if (setpcred(pw->pw_name, (char **)NULL) == -1)
1509 fatal("Failed to set process credentials");
1510#endif /* HAVE_SETPCRED */
1511#ifdef HAVE_LOGIN_CAP
1512# ifdef __bsdi__
1513 setpgid(0, 0);
1514# endif
1515# ifdef USE_PAM
1516 if (options.use_pam) {
1517 do_pam_setcred(use_privsep);
1518 }
1519# endif /* USE_PAM */
1520 if (setusercontext(lc, pw, pw->pw_uid,
1521 (LOGIN_SETALL & ~(LOGIN_SETPATH|LOGIN_SETUSER))) < 0) {
1522 perror("unable to set user context");
1523 exit(1);
1524 }
1525#else
1526# if defined(HAVE_GETLUID) && defined(HAVE_SETLUID)
1527 /* Sets login uid for accounting */
1528 if (getluid() == -1 && setluid(pw->pw_uid) == -1)
1529 error("setluid: %s", strerror(errno));
1530# endif /* defined(HAVE_GETLUID) && defined(HAVE_SETLUID) */
1531
1532 if (setlogin(pw->pw_name) < 0)
1533 error("setlogin failed: %s", strerror(errno));
1534 if (setgid(pw->pw_gid) < 0) {
1535 perror("setgid");
1536 exit(1);
1537 }
1538 /* Initialize the group list. */
1539 if (initgroups(pw->pw_name, pw->pw_gid) < 0) {
1540 perror("initgroups");
1541 exit(1);
1542 }
1543 endgrent();
1544# ifdef USE_PAM
1545 /*
1546 * PAM credentials may take the form of supplementary groups.
1547 * These will have been wiped by the above initgroups() call.
1548 * Reestablish them here.
1549 */
1550 if (options.use_pam) {
1551 do_pam_setcred(use_privsep);
1552 }
1553# endif /* USE_PAM */
1554# if defined(WITH_IRIX_PROJECT) || defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY)
1555 irix_setusercontext(pw);
1556# endif /* defined(WITH_IRIX_PROJECT) || defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY) */
1557# ifdef _AIX
1558 aix_usrinfo(pw);
1559# endif /* _AIX */
1560# ifdef USE_LIBIAF
1561 if (set_id(pw->pw_name) != 0) {
1562 exit(1);
1563 }
1564# endif /* USE_LIBIAF */
1565#endif
1566
1567 if (options.chroot_directory != NULL &&
1568 strcasecmp(options.chroot_directory, "none") != 0) {
1569 tmp = tilde_expand_filename(options.chroot_directory,
1570 pw->pw_uid);
1571 chroot_path = percent_expand(tmp, "h", pw->pw_dir,
1572 "u", pw->pw_name, (char *)NULL);
1573 safely_chroot(chroot_path, pw->pw_uid);
1574 free(tmp);
1575 free(chroot_path);
1576 }
1577
1578#ifdef HAVE_LOGIN_CAP
1579 if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUSER) < 0) {
1580 perror("unable to set user context (setuser)");
1581 exit(1);
1582 }
1583#else
1584 /* Permanently switch to the desired uid. */
1585 permanently_set_uid(pw);
1586#endif
1587 }
1588
1589#ifdef HAVE_CYGWIN
1590 if (is_winnt)
1591#endif
1592 if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
1593 fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
1594
1595#ifdef WITH_SELINUX
1596 ssh_selinux_setup_exec_context(pw->pw_name);
1597#endif
1598}
1599
1600static void
1601do_pwchange(Session *s)
1602{
1603 fflush(NULL);
1604 fprintf(stderr, "WARNING: Your password has expired.\n");
1605 if (s->ttyfd != -1) {
1606 fprintf(stderr,
1607 "You must change your password now and login again!\n");
1608#ifdef PASSWD_NEEDS_USERNAME
1609 execl(_PATH_PASSWD_PROG, "passwd", s->pw->pw_name,
1610 (char *)NULL);
1611#else
1612 execl(_PATH_PASSWD_PROG, "passwd", (char *)NULL);
1613#endif
1614 perror("passwd");
1615 } else {
1616 fprintf(stderr,
1617 "Password change required but no TTY available.\n");
1618 }
1619 exit(1);
1620}
1621
1622static void
1623launch_login(struct passwd *pw, const char *hostname)
1624{
1625 /* Launch login(1). */
1626
1627 execl(LOGIN_PROGRAM, "login", "-h", hostname,
1628#ifdef xxxLOGIN_NEEDS_TERM
1629 (s->term ? s->term : "unknown"),
1630#endif /* LOGIN_NEEDS_TERM */
1631#ifdef LOGIN_NO_ENDOPT
1632 "-p", "-f", pw->pw_name, (char *)NULL);
1633#else
1634 "-p", "-f", "--", pw->pw_name, (char *)NULL);
1635#endif
1636
1637 /* Login couldn't be executed, die. */
1638
1639 perror("login");
1640 exit(1);
1641}
1642
1643static void
1644child_close_fds(void)
1645{
1646 int i;
1647
1648 if (packet_get_connection_in() == packet_get_connection_out())
1649 close(packet_get_connection_in());
1650 else {
1651 close(packet_get_connection_in());
1652 close(packet_get_connection_out());
1653 }
1654 /*
1655 * Close all descriptors related to channels. They will still remain
1656 * open in the parent.
1657 */
1658 /* XXX better use close-on-exec? -markus */
1659 channel_close_all();
1660
1661 /*
1662 * Close any extra file descriptors. Note that there may still be
1663 * descriptors left by system functions. They will be closed later.
1664 */
1665 endpwent();
1666
1667 /*
1668 * Close any extra open file descriptors so that we don't have them
1669 * hanging around in clients. Note that we want to do this after
1670 * initgroups, because at least on Solaris 2.3 it leaves file
1671 * descriptors open.
1672 */
1673 for (i = 3; i < 64; i++)
1674 close(i);
1675}
1676
1677/*
1678 * Performs common processing for the child, such as setting up the
1679 * environment, closing extra file descriptors, setting the user and group
1680 * ids, and executing the command or shell.
1681 */
1682#define ARGV_MAX 10
1683void
1684do_child(Session *s, const char *command)
1685{
1686 extern char **environ;
1687 char **env;
1688 char *argv[ARGV_MAX];
1689 const char *shell, *shell0, *hostname = NULL;
1690 struct passwd *pw = s->pw;
c8c467ee 1691 int r = 0;
16c343f1
PA
1692
1693 /* remove hostkey from the child's memory */
1694 destroy_sensitive_data();
1695
1696 /* Force a password change */
1697 if (s->authctxt->force_pwchange) {
1698 do_setusercontext(pw);
1699 child_close_fds();
1700 do_pwchange(s);
1701 exit(1);
1702 }
1703
1704 /* login(1) is only called if we execute the login shell */
1705 if (options.use_login && command != NULL)
1706 options.use_login = 0;
1707
1708#ifdef _UNICOS
1709 cray_setup(pw->pw_uid, pw->pw_name, command);
1710#endif /* _UNICOS */
1711
1712 /*
1713 * Login(1) does this as well, and it needs uid 0 for the "-h"
1714 * switch, so we let login(1) to this for us.
1715 */
1716 if (!options.use_login) {
1717#ifdef HAVE_OSF_SIA
1718 session_setup_sia(pw, s->ttyfd == -1 ? NULL : s->tty);
1719 if (!check_quietlogin(s, command))
1720 do_motd();
1721#else /* HAVE_OSF_SIA */
1722 /* When PAM is enabled we rely on it to do the nologin check */
1723 if (!options.use_pam)
1724 do_nologin(pw);
1725 do_setusercontext(pw);
1726 /*
1727 * PAM session modules in do_setusercontext may have
1728 * generated messages, so if this in an interactive
1729 * login then display them too.
1730 */
1731 if (!check_quietlogin(s, command))
1732 display_loginmsg();
1733#endif /* HAVE_OSF_SIA */
1734 }
1735
1736#ifdef USE_PAM
1737 if (options.use_pam && !options.use_login && !is_pam_session_open()) {
1738 debug3("PAM session not opened, exiting");
1739 display_loginmsg();
1740 exit(254);
1741 }
1742#endif
1743
1744 /*
1745 * Get the shell from the password data. An empty shell field is
1746 * legal, and means /bin/sh.
1747 */
1748 shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1749
1750 /*
1751 * Make sure $SHELL points to the shell from the password file,
1752 * even if shell is overridden from login.conf
1753 */
1754 env = do_setup_env(s, shell);
1755
1756#ifdef HAVE_LOGIN_CAP
1757 shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
1758#endif
1759
1760 /* we have to stash the hostname before we close our socket. */
1761 if (options.use_login)
1762 hostname = get_remote_name_or_ip(utmp_len,
1763 options.use_dns);
1764 /*
1765 * Close the connection descriptors; note that this is the child, and
1766 * the server will still have the socket open, and it is important
1767 * that we do not shutdown it. Note that the descriptors cannot be
1768 * closed before building the environment, as we call
1769 * get_remote_ipaddr there.
1770 */
1771 child_close_fds();
1772
1773 /*
1774 * Must take new environment into use so that .ssh/rc,
1775 * /etc/ssh/sshrc and xauth are run in the proper environment.
1776 */
1777 environ = env;
1778
1779#if defined(KRB5) && defined(USE_AFS)
1780 /*
1781 * At this point, we check to see if AFS is active and if we have
1782 * a valid Kerberos 5 TGT. If so, it seems like a good idea to see
1783 * if we can (and need to) extend the ticket into an AFS token. If
1784 * we don't do this, we run into potential problems if the user's
1785 * home directory is in AFS and it's not world-readable.
1786 */
1787
1788 if (options.kerberos_get_afs_token && k_hasafs() &&
1789 (s->authctxt->krb5_ctx != NULL)) {
1790 char cell[64];
1791
1792 debug("Getting AFS token");
1793
1794 k_setpag();
1795
1796 if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
1797 krb5_afslog(s->authctxt->krb5_ctx,
1798 s->authctxt->krb5_fwd_ccache, cell, NULL);
1799
1800 krb5_afslog_home(s->authctxt->krb5_ctx,
1801 s->authctxt->krb5_fwd_ccache, NULL, NULL, pw->pw_dir);
1802 }
1803#endif
1804
1805 /* Change current directory to the user's home directory. */
1806 if (chdir(pw->pw_dir) < 0) {
c8c467ee 1807 /* Suppress missing homedir warning for chroot case */
16c343f1 1808#ifdef HAVE_LOGIN_CAP
c8c467ee 1809 r = login_getcapbool(lc, "requirehome", 0);
16c343f1 1810#endif
c8c467ee
PA
1811 if (r || options.chroot_directory == NULL)
1812 fprintf(stderr, "Could not chdir to home "
1813 "directory %s: %s\n", pw->pw_dir,
1814 strerror(errno));
1815 if (r)
1816 exit(1);
16c343f1
PA
1817 }
1818
1819 closefrom(STDERR_FILENO + 1);
1820
1821 if (!options.use_login)
1822 do_rc_files(s, shell);
1823
1824 /* restore SIGPIPE for child */
1825 signal(SIGPIPE, SIG_DFL);
1826
1827 if (s->is_subsystem == SUBSYSTEM_INT_SFTP) {
1828 extern int optind, optreset;
1829 int i;
1830 char *p, *args;
1831
1832 setproctitle("%s@internal-sftp-server", s->pw->pw_name);
cb5eb4f1 1833 args = xstrdup(command ? command : "sftp-server");
16c343f1
PA
1834 for (i = 0, (p = strtok(args, " ")); p; (p = strtok(NULL, " ")))
1835 if (i < ARGV_MAX - 1)
1836 argv[i++] = p;
1837 argv[i] = NULL;
1838 optind = optreset = 1;
1839 __progname = argv[0];
1840 exit(sftp_server_main(i, argv, s->pw));
1841 }
1842
1843 if (options.use_login) {
1844 launch_login(pw, hostname);
1845 /* NEVERREACHED */
1846 }
1847
1848 /* Get the last component of the shell name. */
1849 if ((shell0 = strrchr(shell, '/')) != NULL)
1850 shell0++;
1851 else
1852 shell0 = shell;
1853
1854 /*
1855 * If we have no command, execute the shell. In this case, the shell
1856 * name to be passed in argv[0] is preceded by '-' to indicate that
1857 * this is a login shell.
1858 */
1859 if (!command) {
1860 char argv0[256];
1861
1862 /* Start the shell. Set initial character to '-'. */
1863 argv0[0] = '-';
1864
1865 if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1)
1866 >= sizeof(argv0) - 1) {
1867 errno = EINVAL;
1868 perror(shell);
1869 exit(1);
1870 }
1871
1872 /* Execute the shell. */
1873 argv[0] = argv0;
1874 argv[1] = NULL;
1875 execve(shell, argv, env);
1876
1877 /* Executing the shell failed. */
1878 perror(shell);
1879 exit(1);
1880 }
1881 /*
1882 * Execute the command using the user's shell. This uses the -c
1883 * option to execute the command.
1884 */
1885 argv[0] = (char *) shell0;
1886 argv[1] = "-c";
1887 argv[2] = (char *) command;
1888 argv[3] = NULL;
1889 execve(shell, argv, env);
1890 perror(shell);
1891 exit(1);
1892}
1893
c8c467ee
PA
1894void
1895session_unused(int id)
1896{
1897 debug3("%s: session id %d unused", __func__, id);
1898 if (id >= options.max_sessions ||
1899 id >= sessions_nalloc) {
1900 fatal("%s: insane session id %d (max %d nalloc %d)",
1901 __func__, id, options.max_sessions, sessions_nalloc);
1902 }
1903 bzero(&sessions[id], sizeof(*sessions));
1904 sessions[id].self = id;
1905 sessions[id].used = 0;
1906 sessions[id].chanid = -1;
1907 sessions[id].ptyfd = -1;
1908 sessions[id].ttyfd = -1;
1909 sessions[id].ptymaster = -1;
1910 sessions[id].x11_chanids = NULL;
1911 sessions[id].next_unused = sessions_first_unused;
1912 sessions_first_unused = id;
1913}
1914
16c343f1
PA
1915Session *
1916session_new(void)
1917{
c8c467ee
PA
1918 Session *s, *tmp;
1919
1920 if (sessions_first_unused == -1) {
1921 if (sessions_nalloc >= options.max_sessions)
1922 return NULL;
1923 debug2("%s: allocate (allocated %d max %d)",
1924 __func__, sessions_nalloc, options.max_sessions);
1925 tmp = xrealloc(sessions, sessions_nalloc + 1,
1926 sizeof(*sessions));
1927 if (tmp == NULL) {
1928 error("%s: cannot allocate %d sessions",
1929 __func__, sessions_nalloc + 1);
1930 return NULL;
16c343f1 1931 }
c8c467ee
PA
1932 sessions = tmp;
1933 session_unused(sessions_nalloc++);
16c343f1 1934 }
c8c467ee
PA
1935
1936 if (sessions_first_unused >= sessions_nalloc ||
1937 sessions_first_unused < 0) {
1938 fatal("%s: insane first_unused %d max %d nalloc %d",
1939 __func__, sessions_first_unused, options.max_sessions,
1940 sessions_nalloc);
16c343f1 1941 }
c8c467ee
PA
1942
1943 s = &sessions[sessions_first_unused];
1944 if (s->used) {
1945 fatal("%s: session %d already used",
1946 __func__, sessions_first_unused);
1947 }
1948 sessions_first_unused = s->next_unused;
1949 s->used = 1;
1950 s->next_unused = -1;
1951 debug("session_new: session %d", s->self);
1952
1953 return s;
16c343f1
PA
1954}
1955
1956static void
1957session_dump(void)
1958{
1959 int i;
c8c467ee 1960 for (i = 0; i < sessions_nalloc; i++) {
16c343f1 1961 Session *s = &sessions[i];
c8c467ee
PA
1962
1963 debug("dump: used %d next_unused %d session %d %p "
1964 "channel %d pid %ld",
16c343f1 1965 s->used,
c8c467ee 1966 s->next_unused,
16c343f1
PA
1967 s->self,
1968 s,
1969 s->chanid,
1970 (long)s->pid);
1971 }
1972}
1973
1974int
1975session_open(Authctxt *authctxt, int chanid)
1976{
1977 Session *s = session_new();
1978 debug("session_open: channel %d", chanid);
1979 if (s == NULL) {
1980 error("no more sessions");
1981 return 0;
1982 }
1983 s->authctxt = authctxt;
1984 s->pw = authctxt->pw;
1985 if (s->pw == NULL || !authctxt->valid)
1986 fatal("no user for session %d", s->self);
1987 debug("session_open: session %d: link with channel %d", s->self, chanid);
1988 s->chanid = chanid;
1989 return 1;
1990}
1991
1992Session *
1993session_by_tty(char *tty)
1994{
1995 int i;
c8c467ee 1996 for (i = 0; i < sessions_nalloc; i++) {
16c343f1
PA
1997 Session *s = &sessions[i];
1998 if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) {
1999 debug("session_by_tty: session %d tty %s", i, tty);
2000 return s;
2001 }
2002 }
2003 debug("session_by_tty: unknown tty %.100s", tty);
2004 session_dump();
2005 return NULL;
2006}
2007
2008static Session *
2009session_by_channel(int id)
2010{
2011 int i;
c8c467ee 2012 for (i = 0; i < sessions_nalloc; i++) {
16c343f1
PA
2013 Session *s = &sessions[i];
2014 if (s->used && s->chanid == id) {
c8c467ee
PA
2015 debug("session_by_channel: session %d channel %d",
2016 i, id);
16c343f1
PA
2017 return s;
2018 }
2019 }
2020 debug("session_by_channel: unknown channel %d", id);
2021 session_dump();
2022 return NULL;
2023}
2024
2025static Session *
2026session_by_x11_channel(int id)
2027{
2028 int i, j;
2029
c8c467ee 2030 for (i = 0; i < sessions_nalloc; i++) {
16c343f1
PA
2031 Session *s = &sessions[i];
2032
2033 if (s->x11_chanids == NULL || !s->used)
2034 continue;
2035 for (j = 0; s->x11_chanids[j] != -1; j++) {
2036 if (s->x11_chanids[j] == id) {
2037 debug("session_by_x11_channel: session %d "
2038 "channel %d", s->self, id);
2039 return s;
2040 }
2041 }
2042 }
2043 debug("session_by_x11_channel: unknown channel %d", id);
2044 session_dump();
2045 return NULL;
2046}
2047
2048static Session *
2049session_by_pid(pid_t pid)
2050{
2051 int i;
2052 debug("session_by_pid: pid %ld", (long)pid);
c8c467ee 2053 for (i = 0; i < sessions_nalloc; i++) {
16c343f1
PA
2054 Session *s = &sessions[i];
2055 if (s->used && s->pid == pid)
2056 return s;
2057 }
2058 error("session_by_pid: unknown pid %ld", (long)pid);
2059 session_dump();
2060 return NULL;
2061}
2062
2063static int
2064session_window_change_req(Session *s)
2065{
2066 s->col = packet_get_int();
2067 s->row = packet_get_int();
2068 s->xpixel = packet_get_int();
2069 s->ypixel = packet_get_int();
2070 packet_check_eom();
2071 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
2072 return 1;
2073}
2074
2075static int
2076session_pty_req(Session *s)
2077{
2078 u_int len;
2079 int n_bytes;
2080
2081 if (no_pty_flag) {
2082 debug("Allocating a pty not permitted for this authentication.");
2083 return 0;
2084 }
2085 if (s->ttyfd != -1) {
2086 packet_disconnect("Protocol error: you already have a pty.");
2087 return 0;
2088 }
2089
2090 s->term = packet_get_string(&len);
2091
2092 if (compat20) {
2093 s->col = packet_get_int();
2094 s->row = packet_get_int();
2095 } else {
2096 s->row = packet_get_int();
2097 s->col = packet_get_int();
2098 }
2099 s->xpixel = packet_get_int();
2100 s->ypixel = packet_get_int();
2101
2102 if (strcmp(s->term, "") == 0) {
2103 xfree(s->term);
2104 s->term = NULL;
2105 }
2106
2107 /* Allocate a pty and open it. */
2108 debug("Allocating pty.");
c8c467ee
PA
2109 if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty,
2110 sizeof(s->tty)))) {
16c343f1
PA
2111 if (s->term)
2112 xfree(s->term);
2113 s->term = NULL;
2114 s->ptyfd = -1;
2115 s->ttyfd = -1;
2116 error("session_pty_req: session %d alloc failed", s->self);
2117 return 0;
2118 }
2119 debug("session_pty_req: session %d alloc %s", s->self, s->tty);
2120
2121 /* for SSH1 the tty modes length is not given */
2122 if (!compat20)
2123 n_bytes = packet_remaining();
2124 tty_parse_modes(s->ttyfd, &n_bytes);
2125
2126 if (!use_privsep)
2127 pty_setowner(s->pw, s->tty);
2128
2129 /* Set window size from the packet. */
2130 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
2131
2132 packet_check_eom();
2133 session_proctitle(s);
2134 return 1;
2135}
2136
2137static int
2138session_subsystem_req(Session *s)
2139{
2140 struct stat st;
2141 u_int len;
2142 int success = 0;
2143 char *prog, *cmd, *subsys = packet_get_string(&len);
2144 u_int i;
2145
2146 packet_check_eom();
2147 logit("subsystem request for %.100s", subsys);
2148
2149 for (i = 0; i < options.num_subsystems; i++) {
2150 if (strcmp(subsys, options.subsystem_name[i]) == 0) {
2151 prog = options.subsystem_command[i];
2152 cmd = options.subsystem_args[i];
2153 if (!strcmp(INTERNAL_SFTP_NAME, prog)) {
2154 s->is_subsystem = SUBSYSTEM_INT_SFTP;
2155 } else if (stat(prog, &st) < 0) {
2156 error("subsystem: cannot stat %s: %s", prog,
2157 strerror(errno));
2158 break;
2159 } else {
2160 s->is_subsystem = SUBSYSTEM_EXT;
2161 }
2162 debug("subsystem: exec() %s", cmd);
c8c467ee 2163 success = do_exec(s, cmd) == 0;
16c343f1
PA
2164 break;
2165 }
2166 }
2167
2168 if (!success)
2169 logit("subsystem request for %.100s failed, subsystem not found",
2170 subsys);
2171
2172 xfree(subsys);
2173 return success;
2174}
2175
2176static int
2177session_x11_req(Session *s)
2178{
2179 int success;
2180
2181 if (s->auth_proto != NULL || s->auth_data != NULL) {
2182 error("session_x11_req: session %d: "
2183 "x11 forwarding already active", s->self);
2184 return 0;
2185 }
2186 s->single_connection = packet_get_char();
2187 s->auth_proto = packet_get_string(NULL);
2188 s->auth_data = packet_get_string(NULL);
2189 s->screen = packet_get_int();
2190 packet_check_eom();
2191
2192 success = session_setup_x11fwd(s);
2193 if (!success) {
2194 xfree(s->auth_proto);
2195 xfree(s->auth_data);
2196 s->auth_proto = NULL;
2197 s->auth_data = NULL;
2198 }
2199 return success;
2200}
2201
2202static int
2203session_shell_req(Session *s)
2204{
2205 packet_check_eom();
c8c467ee 2206 return do_exec(s, NULL) == 0;
16c343f1
PA
2207}
2208
2209static int
2210session_exec_req(Session *s)
2211{
c8c467ee
PA
2212 u_int len, success;
2213
16c343f1
PA
2214 char *command = packet_get_string(&len);
2215 packet_check_eom();
c8c467ee 2216 success = do_exec(s, command) == 0;
16c343f1 2217 xfree(command);
c8c467ee 2218 return success;
16c343f1
PA
2219}
2220
2221static int
2222session_break_req(Session *s)
2223{
2224
2225 packet_get_int(); /* ignored */
2226 packet_check_eom();
2227
c8c467ee 2228 if (s->ttyfd == -1 || tcsendbreak(s->ttyfd, 0) < 0)
16c343f1
PA
2229 return 0;
2230 return 1;
2231}
2232
2233static int
2234session_env_req(Session *s)
2235{
2236 char *name, *val;
2237 u_int name_len, val_len, i;
2238
2239 name = packet_get_string(&name_len);
2240 val = packet_get_string(&val_len);
2241 packet_check_eom();
2242
2243 /* Don't set too many environment variables */
2244 if (s->num_env > 128) {
2245 debug2("Ignoring env request %s: too many env vars", name);
2246 goto fail;
2247 }
2248
2249 for (i = 0; i < options.num_accept_env; i++) {
2250 if (match_pattern(name, options.accept_env[i])) {
2251 debug2("Setting env %d: %s=%s", s->num_env, name, val);
2252 s->env = xrealloc(s->env, s->num_env + 1,
2253 sizeof(*s->env));
2254 s->env[s->num_env].name = name;
2255 s->env[s->num_env].val = val;
2256 s->num_env++;
2257 return (1);
2258 }
2259 }
2260 debug2("Ignoring env request %s: disallowed name", name);
2261
2262 fail:
2263 xfree(name);
2264 xfree(val);
2265 return (0);
2266}
2267
2268static int
2269session_auth_agent_req(Session *s)
2270{
2271 static int called = 0;
2272 packet_check_eom();
c8c467ee 2273 if (no_agent_forwarding_flag || !options.allow_agent_forwarding) {
16c343f1
PA
2274 debug("session_auth_agent_req: no_agent_forwarding_flag");
2275 return 0;
2276 }
2277 if (called) {
2278 return 0;
2279 } else {
2280 called = 1;
2281 return auth_input_request_forwarding(s->pw);
2282 }
2283}
2284
2285int
2286session_input_channel_req(Channel *c, const char *rtype)
2287{
2288 int success = 0;
2289 Session *s;
2290
2291 if ((s = session_by_channel(c->self)) == NULL) {
2292 logit("session_input_channel_req: no session %d req %.100s",
2293 c->self, rtype);
2294 return 0;
2295 }
2296 debug("session_input_channel_req: session %d req %s", s->self, rtype);
2297
2298 /*
2299 * a session is in LARVAL state until a shell, a command
2300 * or a subsystem is executed
2301 */
2302 if (c->type == SSH_CHANNEL_LARVAL) {
2303 if (strcmp(rtype, "shell") == 0) {
2304 success = session_shell_req(s);
2305 } else if (strcmp(rtype, "exec") == 0) {
2306 success = session_exec_req(s);
2307 } else if (strcmp(rtype, "pty-req") == 0) {
2308 success = session_pty_req(s);
2309 } else if (strcmp(rtype, "x11-req") == 0) {
2310 success = session_x11_req(s);
2311 } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
2312 success = session_auth_agent_req(s);
2313 } else if (strcmp(rtype, "subsystem") == 0) {
2314 success = session_subsystem_req(s);
2315 } else if (strcmp(rtype, "env") == 0) {
2316 success = session_env_req(s);
2317 }
2318 }
2319 if (strcmp(rtype, "window-change") == 0) {
2320 success = session_window_change_req(s);
2321 } else if (strcmp(rtype, "break") == 0) {
2322 success = session_break_req(s);
2323 }
2324
2325 return success;
2326}
2327
2328void
c8c467ee 2329session_set_fds(Session *s, int fdin, int fdout, int fderr, int is_tty)
16c343f1
PA
2330{
2331 if (!compat20)
2332 fatal("session_set_fds: called for proto != 2.0");
2333 /*
2334 * now that have a child and a pipe to the child,
2335 * we can activate our channel and register the fd's
2336 */
2337 if (s->chanid == -1)
2338 fatal("no channel for session %d", s->self);
2339 channel_set_fds(s->chanid,
2340 fdout, fdin, fderr,
2341 fderr == -1 ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
c8c467ee 2342 1, is_tty, CHAN_SES_WINDOW_DEFAULT);
16c343f1
PA
2343}
2344
2345/*
2346 * Function to perform pty cleanup. Also called if we get aborted abnormally
2347 * (e.g., due to a dropped connection).
2348 */
2349void
2350session_pty_cleanup2(Session *s)
2351{
2352 if (s == NULL) {
2353 error("session_pty_cleanup: no session");
2354 return;
2355 }
2356 if (s->ttyfd == -1)
2357 return;
2358
2359 debug("session_pty_cleanup: session %d release %s", s->self, s->tty);
2360
2361 /* Record that the user has logged out. */
2362 if (s->pid != 0)
2363 record_logout(s->pid, s->tty, s->pw->pw_name);
2364
2365 /* Release the pseudo-tty. */
2366 if (getuid() == 0)
2367 pty_release(s->tty);
2368
2369 /*
2370 * Close the server side of the socket pairs. We must do this after
2371 * the pty cleanup, so that another process doesn't get this pty
2372 * while we're still cleaning up.
2373 */
c8c467ee
PA
2374 if (s->ptymaster != -1 && close(s->ptymaster) < 0)
2375 error("close(s->ptymaster/%d): %s",
2376 s->ptymaster, strerror(errno));
16c343f1
PA
2377
2378 /* unlink pty from session */
2379 s->ttyfd = -1;
2380}
2381
2382void
2383session_pty_cleanup(Session *s)
2384{
2385 PRIVSEP(session_pty_cleanup2(s));
2386}
2387
2388static char *
2389sig2name(int sig)
2390{
2391#define SSH_SIG(x) if (sig == SIG ## x) return #x
2392 SSH_SIG(ABRT);
2393 SSH_SIG(ALRM);
2394 SSH_SIG(FPE);
2395 SSH_SIG(HUP);
2396 SSH_SIG(ILL);
2397 SSH_SIG(INT);
2398 SSH_SIG(KILL);
2399 SSH_SIG(PIPE);
2400 SSH_SIG(QUIT);
2401 SSH_SIG(SEGV);
2402 SSH_SIG(TERM);
2403 SSH_SIG(USR1);
2404 SSH_SIG(USR2);
2405#undef SSH_SIG
2406 return "SIG@openssh.com";
2407}
2408
2409static void
2410session_close_x11(int id)
2411{
2412 Channel *c;
2413
2414 if ((c = channel_by_id(id)) == NULL) {
2415 debug("session_close_x11: x11 channel %d missing", id);
2416 } else {
2417 /* Detach X11 listener */
2418 debug("session_close_x11: detach x11 channel %d", id);
2419 channel_cancel_cleanup(id);
2420 if (c->ostate != CHAN_OUTPUT_CLOSED)
2421 chan_mark_dead(c);
2422 }
2423}
2424
2425static void
2426session_close_single_x11(int id, void *arg)
2427{
2428 Session *s;
2429 u_int i;
2430
2431 debug3("session_close_single_x11: channel %d", id);
2432 channel_cancel_cleanup(id);
2433 if ((s = session_by_x11_channel(id)) == NULL)
2434 fatal("session_close_single_x11: no x11 channel %d", id);
2435 for (i = 0; s->x11_chanids[i] != -1; i++) {
2436 debug("session_close_single_x11: session %d: "
2437 "closing channel %d", s->self, s->x11_chanids[i]);
2438 /*
2439 * The channel "id" is already closing, but make sure we
2440 * close all of its siblings.
2441 */
2442 if (s->x11_chanids[i] != id)
2443 session_close_x11(s->x11_chanids[i]);
2444 }
2445 xfree(s->x11_chanids);
2446 s->x11_chanids = NULL;
2447 if (s->display) {
2448 xfree(s->display);
2449 s->display = NULL;
2450 }
2451 if (s->auth_proto) {
2452 xfree(s->auth_proto);
2453 s->auth_proto = NULL;
2454 }
2455 if (s->auth_data) {
2456 xfree(s->auth_data);
2457 s->auth_data = NULL;
2458 }
2459 if (s->auth_display) {
2460 xfree(s->auth_display);
2461 s->auth_display = NULL;
2462 }
2463}
2464
2465static void
2466session_exit_message(Session *s, int status)
2467{
2468 Channel *c;
2469
2470 if ((c = channel_lookup(s->chanid)) == NULL)
2471 fatal("session_exit_message: session %d: no channel %d",
2472 s->self, s->chanid);
2473 debug("session_exit_message: session %d channel %d pid %ld",
2474 s->self, s->chanid, (long)s->pid);
2475
2476 if (WIFEXITED(status)) {
2477 channel_request_start(s->chanid, "exit-status", 0);
2478 packet_put_int(WEXITSTATUS(status));
2479 packet_send();
2480 } else if (WIFSIGNALED(status)) {
2481 channel_request_start(s->chanid, "exit-signal", 0);
2482 packet_put_cstring(sig2name(WTERMSIG(status)));
2483#ifdef WCOREDUMP
2484 packet_put_char(WCOREDUMP(status)? 1 : 0);
2485#else /* WCOREDUMP */
2486 packet_put_char(0);
2487#endif /* WCOREDUMP */
2488 packet_put_cstring("");
2489 packet_put_cstring("");
2490 packet_send();
2491 } else {
2492 /* Some weird exit cause. Just exit. */
2493 packet_disconnect("wait returned status %04x.", status);
2494 }
2495
2496 /* disconnect channel */
2497 debug("session_exit_message: release channel %d", s->chanid);
2498
2499 /*
2500 * Adjust cleanup callback attachment to send close messages when
2501 * the channel gets EOF. The session will be then be closed
2502 * by session_close_by_channel when the childs close their fds.
2503 */
2504 channel_register_cleanup(c->self, session_close_by_channel, 1);
2505
2506 /*
2507 * emulate a write failure with 'chan_write_failed', nobody will be
2508 * interested in data we write.
2509 * Note that we must not call 'chan_read_failed', since there could
2510 * be some more data waiting in the pipe.
2511 */
2512 if (c->ostate != CHAN_OUTPUT_CLOSED)
2513 chan_write_failed(c);
2514}
2515
2516void
2517session_close(Session *s)
2518{
2519 u_int i;
2520
2521 debug("session_close: session %d pid %ld", s->self, (long)s->pid);
2522 if (s->ttyfd != -1)
2523 session_pty_cleanup(s);
2524 if (s->term)
2525 xfree(s->term);
2526 if (s->display)
2527 xfree(s->display);
2528 if (s->x11_chanids)
2529 xfree(s->x11_chanids);
2530 if (s->auth_display)
2531 xfree(s->auth_display);
2532 if (s->auth_data)
2533 xfree(s->auth_data);
2534 if (s->auth_proto)
2535 xfree(s->auth_proto);
16c343f1
PA
2536 if (s->env != NULL) {
2537 for (i = 0; i < s->num_env; i++) {
2538 xfree(s->env[i].name);
2539 xfree(s->env[i].val);
2540 }
2541 xfree(s->env);
2542 }
2543 session_proctitle(s);
c8c467ee 2544 session_unused(s->self);
16c343f1
PA
2545}
2546
2547void
2548session_close_by_pid(pid_t pid, int status)
2549{
2550 Session *s = session_by_pid(pid);
2551 if (s == NULL) {
2552 debug("session_close_by_pid: no session for pid %ld",
2553 (long)pid);
2554 return;
2555 }
2556 if (s->chanid != -1)
2557 session_exit_message(s, status);
2558 if (s->ttyfd != -1)
2559 session_pty_cleanup(s);
2560 s->pid = 0;
2561}
2562
2563/*
2564 * this is called when a channel dies before
2565 * the session 'child' itself dies
2566 */
2567void
2568session_close_by_channel(int id, void *arg)
2569{
2570 Session *s = session_by_channel(id);
2571 u_int i;
2572
2573 if (s == NULL) {
2574 debug("session_close_by_channel: no session for id %d", id);
2575 return;
2576 }
2577 debug("session_close_by_channel: channel %d child %ld",
2578 id, (long)s->pid);
2579 if (s->pid != 0) {
2580 debug("session_close_by_channel: channel %d: has child", id);
2581 /*
2582 * delay detach of session, but release pty, since
2583 * the fd's to the child are already closed
2584 */
2585 if (s->ttyfd != -1)
2586 session_pty_cleanup(s);
2587 return;
2588 }
2589 /* detach by removing callback */
2590 channel_cancel_cleanup(s->chanid);
2591
2592 /* Close any X11 listeners associated with this session */
2593 if (s->x11_chanids != NULL) {
2594 for (i = 0; s->x11_chanids[i] != -1; i++) {
2595 session_close_x11(s->x11_chanids[i]);
2596 s->x11_chanids[i] = -1;
2597 }
2598 }
2599
2600 s->chanid = -1;
2601 session_close(s);
2602}
2603
2604void
2605session_destroy_all(void (*closefunc)(Session *))
2606{
2607 int i;
c8c467ee 2608 for (i = 0; i < sessions_nalloc; i++) {
16c343f1
PA
2609 Session *s = &sessions[i];
2610 if (s->used) {
2611 if (closefunc != NULL)
2612 closefunc(s);
2613 else
2614 session_close(s);
2615 }
2616 }
2617}
2618
2619static char *
2620session_tty_list(void)
2621{
2622 static char buf[1024];
2623 int i;
2624 char *cp;
2625
2626 buf[0] = '\0';
c8c467ee 2627 for (i = 0; i < sessions_nalloc; i++) {
16c343f1
PA
2628 Session *s = &sessions[i];
2629 if (s->used && s->ttyfd != -1) {
2630
2631 if (strncmp(s->tty, "/dev/", 5) != 0) {
2632 cp = strrchr(s->tty, '/');
2633 cp = (cp == NULL) ? s->tty : cp + 1;
2634 } else
2635 cp = s->tty + 5;
2636
2637 if (buf[0] != '\0')
2638 strlcat(buf, ",", sizeof buf);
2639 strlcat(buf, cp, sizeof buf);
2640 }
2641 }
2642 if (buf[0] == '\0')
2643 strlcpy(buf, "notty", sizeof buf);
2644 return buf;
2645}
2646
2647void
2648session_proctitle(Session *s)
2649{
2650 if (s->pw == NULL)
2651 error("no user for session %d", s->self);
2652 else
2653 setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
2654}
2655
2656int
2657session_setup_x11fwd(Session *s)
2658{
2659 struct stat st;
2660 char display[512], auth_display[512];
2661 char hostname[MAXHOSTNAMELEN];
2662 u_int i;
2663
2664 if (no_x11_forwarding_flag) {
2665 packet_send_debug("X11 forwarding disabled in user configuration file.");
2666 return 0;
2667 }
2668 if (!options.x11_forwarding) {
2669 debug("X11 forwarding disabled in server configuration file.");
2670 return 0;
2671 }
2672 if (!options.xauth_location ||
2673 (stat(options.xauth_location, &st) == -1)) {
2674 packet_send_debug("No xauth program; cannot forward with spoofing.");
2675 return 0;
2676 }
2677 if (options.use_login) {
2678 packet_send_debug("X11 forwarding disabled; "
2679 "not compatible with UseLogin=yes.");
2680 return 0;
2681 }
2682 if (s->display != NULL) {
2683 debug("X11 display already set.");
2684 return 0;
2685 }
2686 if (x11_create_display_inet(options.x11_display_offset,
2687 options.x11_use_localhost, s->single_connection,
2688 &s->display_number, &s->x11_chanids) == -1) {
2689 debug("x11_create_display_inet failed.");
2690 return 0;
2691 }
2692 for (i = 0; s->x11_chanids[i] != -1; i++) {
2693 channel_register_cleanup(s->x11_chanids[i],
2694 session_close_single_x11, 0);
2695 }
2696
2697 /* Set up a suitable value for the DISPLAY variable. */
2698 if (gethostname(hostname, sizeof(hostname)) < 0)
2699 fatal("gethostname: %.100s", strerror(errno));
2700 /*
2701 * auth_display must be used as the displayname when the
2702 * authorization entry is added with xauth(1). This will be
2703 * different than the DISPLAY string for localhost displays.
2704 */
2705 if (options.x11_use_localhost) {
2706 snprintf(display, sizeof display, "localhost:%u.%u",
2707 s->display_number, s->screen);
2708 snprintf(auth_display, sizeof auth_display, "unix:%u.%u",
2709 s->display_number, s->screen);
2710 s->display = xstrdup(display);
2711 s->auth_display = xstrdup(auth_display);
2712 } else {
2713#ifdef IPADDR_IN_DISPLAY
2714 struct hostent *he;
2715 struct in_addr my_addr;
2716
2717 he = gethostbyname(hostname);
2718 if (he == NULL) {
2719 error("Can't get IP address for X11 DISPLAY.");
2720 packet_send_debug("Can't get IP address for X11 DISPLAY.");
2721 return 0;
2722 }
2723 memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr));
2724 snprintf(display, sizeof display, "%.50s:%u.%u", inet_ntoa(my_addr),
2725 s->display_number, s->screen);
2726#else
2727 snprintf(display, sizeof display, "%.400s:%u.%u", hostname,
2728 s->display_number, s->screen);
2729#endif
2730 s->display = xstrdup(display);
2731 s->auth_display = xstrdup(display);
2732 }
2733
2734 return 1;
2735}
2736
2737static void
2738do_authenticated2(Authctxt *authctxt)
2739{
2740 server_loop2(authctxt);
2741}
2742
2743void
2744do_cleanup(Authctxt *authctxt)
2745{
2746 static int called = 0;
2747
2748 debug("do_cleanup");
2749
2750 /* no cleanup if we're in the child for login shell */
2751 if (is_child)
2752 return;
2753
2754 /* avoid double cleanup */
2755 if (called)
2756 return;
2757 called = 1;
2758
2759 if (authctxt == NULL)
2760 return;
2761
2762#ifdef USE_PAM
2763 if (options.use_pam) {
2764 sshpam_cleanup();
2765 sshpam_thread_cleanup();
2766 }
2767#endif
2768
2769 if (!authctxt->authenticated)
2770 return;
2771
2772#ifdef KRB5
2773 if (options.kerberos_ticket_cleanup &&
2774 authctxt->krb5_ctx)
2775 krb5_cleanup_proc(authctxt);
2776#endif
2777
2778#ifdef GSSAPI
2779 if (compat20 && options.gss_cleanup_creds)
2780 ssh_gssapi_cleanup_creds();
2781#endif
2782
2783 /* remove agent socket */
2784 auth_sock_cleanup_proc(authctxt->pw);
2785
2786 /*
2787 * Cleanup ptys/utmp only if privsep is disabled,
2788 * or if running in monitor.
2789 */
2790 if (!use_privsep || mm_is_monitor())
2791 session_destroy_all(session_pty_cleanup2);
2792}