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1 /*
2  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
3  *                    All rights reserved
4  *
5  * As far as I am concerned, the code I have written for this software
6  * can be used freely for any purpose.  Any derived versions of this
7  * software must be clearly marked as such, and if the derived work is
8  * incompatible with the protocol description in the RFC file, it must be
9  * called by a name other than "ssh" or "Secure Shell".
10  *
11  * SSH2 support by Markus Friedl.
12  * Copyright (c) 2000 Markus Friedl. All rights reserved.
13  *
14  * Redistribution and use in source and binary forms, with or without
15  * modification, are permitted provided that the following conditions
16  * are met:
17  * 1. Redistributions of source code must retain the above copyright
18  *    notice, this list of conditions and the following disclaimer.
19  * 2. Redistributions in binary form must reproduce the above copyright
20  *    notice, this list of conditions and the following disclaimer in the
21  *    documentation and/or other materials provided with the distribution.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
24  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
25  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
26  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
27  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
28  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
29  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
30  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
31  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
32  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
33  */
34
35 #include "includes.h"
36 RCSID("$OpenBSD: session.c,v 1.43 2000/11/06 23:04:56 markus Exp $");
37
38 #include "xmalloc.h"
39 #include "ssh.h"
40 #include "pty.h"
41 #include "packet.h"
42 #include "buffer.h"
43 #include "mpaux.h"
44 #include "servconf.h"
45 #include "uidswap.h"
46 #include "compat.h"
47 #include "channels.h"
48 #include "nchan.h"
49
50 #include "bufaux.h"
51 #include "ssh2.h"
52 #include "auth.h"
53 #include "auth-options.h"
54
55 #ifdef WITH_IRIX_PROJECT
56 #include <proj.h>
57 #endif /* WITH_IRIX_PROJECT */
58 #ifdef WITH_IRIX_JOBS
59 #include <sys/resource.h>
60 #endif
61
62 #if defined(HAVE_USERSEC_H)
63 #include <usersec.h>
64 #endif
65
66 #ifdef HAVE_OSF_SIA
67 # include <sia.h>
68 # include <siad.h>
69 #endif
70
71 #ifdef HAVE_CYGWIN
72 #include <windows.h>
73 #include <sys/cygwin.h>
74 #define is_winnt       (GetVersion() < 0x80000000)
75 #endif
76
77 /* AIX limits */
78 #if defined(HAVE_GETUSERATTR) && !defined(S_UFSIZE_HARD) && defined(S_UFSIZE)
79 # define S_UFSIZE_HARD  S_UFSIZE "_hard"
80 # define S_UCPU_HARD  S_UCPU "_hard"
81 # define S_UDATA_HARD  S_UDATA "_hard"
82 # define S_USTACK_HARD  S_USTACK "_hard"
83 # define S_URSS_HARD  S_URSS "_hard"
84 # define S_UCORE_HARD  S_UCORE "_hard"
85 # define S_UNOFILE_HARD S_UNOFILE "_hard"
86 #endif
87
88 #ifdef HAVE_LOGIN_CAP
89 #include <login_cap.h>
90 #endif
91
92 /* types */
93
94 #define TTYSZ 64
95 typedef struct Session Session;
96 struct Session {
97         int     used;
98         int     self;
99         int     extended;
100         struct  passwd *pw;
101         pid_t   pid;
102         /* tty */
103         char    *term;
104         int     ptyfd, ttyfd, ptymaster;
105         int     row, col, xpixel, ypixel;
106         char    tty[TTYSZ];
107         /* X11 */
108         char    *display;
109         int     screen;
110         char    *auth_proto;
111         char    *auth_data;
112         int     single_connection;
113         /* proto 2 */
114         int     chanid;
115 };
116
117 /* func */
118
119 Session *session_new(void);
120 void    session_set_fds(Session *s, int fdin, int fdout, int fderr);
121 void    session_pty_cleanup(Session *s);
122 void    session_proctitle(Session *s);
123 void    do_exec_pty(Session *s, const char *command, struct passwd * pw);
124 void    do_exec_no_pty(Session *s, const char *command, struct passwd * pw);
125 void    do_login(Session *s, const char *command);
126
127 void
128 do_child(const char *command, struct passwd * pw, const char *term,
129     const char *display, const char *auth_proto,
130     const char *auth_data, const char *ttyname);
131
132 /* import */
133 extern ServerOptions options;
134 #ifdef HAVE___PROGNAME
135 extern char *__progname;
136 #else /* HAVE___PROGNAME */
137 static const char *__progname = "sshd";
138 #endif /* HAVE___PROGNAME */
139
140 extern int log_stderr;
141 extern int debug_flag;
142 extern unsigned int utmp_len;
143
144 extern int startup_pipe;
145
146 /* Local Xauthority file. */
147 static char *xauthfile;
148
149 /* original command from peer. */
150 char *original_command = NULL; 
151
152 /* data */
153 #define MAX_SESSIONS 10
154 Session sessions[MAX_SESSIONS];
155
156 #ifdef WITH_AIXAUTHENTICATE
157 /* AIX's lastlogin message, set in auth1.c */
158 char *aixloginmsg;
159 #endif /* WITH_AIXAUTHENTICATE */
160
161 #ifdef HAVE_LOGIN_CAP
162 static login_cap_t *lc;
163 #endif
164
165 /*
166  * Remove local Xauthority file.
167  */
168 void
169 xauthfile_cleanup_proc(void *ignore)
170 {
171         debug("xauthfile_cleanup_proc called");
172
173         if (xauthfile != NULL) {
174                 char *p;
175                 unlink(xauthfile);
176                 p = strrchr(xauthfile, '/');
177                 if (p != NULL) {
178                         *p = '\0';
179                         rmdir(xauthfile);
180                 }
181                 xfree(xauthfile);
182                 xauthfile = NULL;
183         }
184 }
185
186 /*
187  * Function to perform cleanup if we get aborted abnormally (e.g., due to a
188  * dropped connection).
189  */
190 void
191 pty_cleanup_proc(void *session)
192 {
193         Session *s=session;
194         if (s == NULL)
195                 fatal("pty_cleanup_proc: no session");
196         debug("pty_cleanup_proc: %s", s->tty);
197
198         if (s->pid != 0) {
199                 /* Record that the user has logged out. */
200                 record_logout(s->pid, s->tty);
201         }
202
203         /* Release the pseudo-tty. */
204         pty_release(s->tty);
205 }
206
207 /*
208  * Prepares for an interactive session.  This is called after the user has
209  * been successfully authenticated.  During this message exchange, pseudo
210  * terminals are allocated, X11, TCP/IP, and authentication agent forwardings
211  * are requested, etc.
212  */
213 void
214 do_authenticated(struct passwd * pw)
215 {
216         Session *s;
217         int type, fd;
218         int compression_level = 0, enable_compression_after_reply = 0;
219         int have_pty = 0;
220         char *command;
221         int n_bytes;
222         int plen;
223         unsigned int proto_len, data_len, dlen;
224
225         /*
226          * Cancel the alarm we set to limit the time taken for
227          * authentication.
228          */
229         alarm(0);
230         if (startup_pipe != -1) {
231                 close(startup_pipe);
232                 startup_pipe = -1;
233         }
234
235         /*
236          * Inform the channel mechanism that we are the server side and that
237          * the client may request to connect to any port at all. (The user
238          * could do it anyway, and we wouldn\'t know what is permitted except
239          * by the client telling us, so we can equally well trust the client
240          * not to request anything bogus.)
241          */
242         if (!no_port_forwarding_flag && options.allow_tcp_forwarding)
243                 channel_permit_all_opens();
244
245         s = session_new();
246         s->pw = pw;
247
248 #if defined(HAVE_LOGIN_CAP) && defined(HAVE_PW_CLASS_IN_PASSWD)
249         if ((lc = login_getclass(pw->pw_class)) == NULL) {
250                 error("unable to get login class");
251                 return;
252         }
253 #endif
254
255         /*
256          * We stay in this loop until the client requests to execute a shell
257          * or a command.
258          */
259         for (;;) {
260                 int success = 0;
261
262                 /* Get a packet from the client. */
263                 type = packet_read(&plen);
264
265                 /* Process the packet. */
266                 switch (type) {
267                 case SSH_CMSG_REQUEST_COMPRESSION:
268                         packet_integrity_check(plen, 4, type);
269                         compression_level = packet_get_int();
270                         if (compression_level < 1 || compression_level > 9) {
271                                 packet_send_debug("Received illegal compression level %d.",
272                                      compression_level);
273                                 break;
274                         }
275                         /* Enable compression after we have responded with SUCCESS. */
276                         enable_compression_after_reply = 1;
277                         success = 1;
278                         break;
279
280                 case SSH_CMSG_REQUEST_PTY:
281                         if (no_pty_flag) {
282                                 debug("Allocating a pty not permitted for this authentication.");
283                                 break;
284                         }
285                         if (have_pty)
286                                 packet_disconnect("Protocol error: you already have a pty.");
287
288                         debug("Allocating pty.");
289
290                         /* Allocate a pty and open it. */
291                         if (!pty_allocate(&s->ptyfd, &s->ttyfd, s->tty,
292                             sizeof(s->tty))) {
293                                 error("Failed to allocate pty.");
294                                 break;
295                         }
296                         fatal_add_cleanup(pty_cleanup_proc, (void *)s);
297                         pty_setowner(pw, s->tty);
298
299                         /* Get TERM from the packet.  Note that the value may be of arbitrary length. */
300                         s->term = packet_get_string(&dlen);
301                         packet_integrity_check(dlen, strlen(s->term), type);
302                         /* packet_integrity_check(plen, 4 + dlen + 4*4 + n_bytes, type); */
303                         /* Remaining bytes */
304                         n_bytes = plen - (4 + dlen + 4 * 4);
305
306                         if (strcmp(s->term, "") == 0) {
307                                 xfree(s->term);
308                                 s->term = NULL;
309                         }
310                         /* Get window size from the packet. */
311                         s->row = packet_get_int();
312                         s->col = packet_get_int();
313                         s->xpixel = packet_get_int();
314                         s->ypixel = packet_get_int();
315                         pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
316
317                         /* Get tty modes from the packet. */
318                         tty_parse_modes(s->ttyfd, &n_bytes);
319                         packet_integrity_check(plen, 4 + dlen + 4 * 4 + n_bytes, type);
320
321                         session_proctitle(s);
322
323                         /* Indicate that we now have a pty. */
324                         success = 1;
325                         have_pty = 1;
326                         break;
327
328                 case SSH_CMSG_X11_REQUEST_FORWARDING:
329                         if (!options.x11_forwarding) {
330                                 packet_send_debug("X11 forwarding disabled in server configuration file.");
331                                 break;
332                         }
333                         if (!options.xauth_location) {
334                                 packet_send_debug("No xauth program; cannot forward with spoofing.");
335                                 break;
336                         }
337                         if (no_x11_forwarding_flag) {
338                                 packet_send_debug("X11 forwarding not permitted for this authentication.");
339                                 break;
340                         }
341                         debug("Received request for X11 forwarding with auth spoofing.");
342                         if (s->display != NULL)
343                                 packet_disconnect("Protocol error: X11 display already set.");
344
345                         s->auth_proto = packet_get_string(&proto_len);
346                         s->auth_data = packet_get_string(&data_len);
347                         packet_integrity_check(plen, 4 + proto_len + 4 + data_len + 4, type);
348
349                         if (packet_get_protocol_flags() & SSH_PROTOFLAG_SCREEN_NUMBER)
350                                 s->screen = packet_get_int();
351                         else
352                                 s->screen = 0;
353                         s->display = x11_create_display_inet(s->screen, options.x11_display_offset);
354
355                         if (s->display == NULL)
356                                 break;
357
358                         /* Setup to always have a local .Xauthority. */
359                         xauthfile = xmalloc(MAXPATHLEN);
360                         strlcpy(xauthfile, "/tmp/ssh-XXXXXXXX", MAXPATHLEN);
361                         temporarily_use_uid(pw->pw_uid);
362                         if (mkdtemp(xauthfile) == NULL) {
363                                 restore_uid();
364                                 error("private X11 dir: mkdtemp %s failed: %s",
365                                     xauthfile, strerror(errno));
366                                 xfree(xauthfile);
367                                 xauthfile = NULL;
368                                 /* XXXX remove listening channels */
369                                 break;
370                         }
371                         strlcat(xauthfile, "/cookies", MAXPATHLEN);
372                         fd = open(xauthfile, O_RDWR|O_CREAT|O_EXCL, 0600);
373                         if (fd >= 0)
374                                 close(fd);
375                         restore_uid();
376                         fatal_add_cleanup(xauthfile_cleanup_proc, NULL);
377                         success = 1;
378                         break;
379
380                 case SSH_CMSG_AGENT_REQUEST_FORWARDING:
381                         if (no_agent_forwarding_flag || compat13) {
382                                 debug("Authentication agent forwarding not permitted for this authentication.");
383                                 break;
384                         }
385                         debug("Received authentication agent forwarding request.");
386                         success = auth_input_request_forwarding(pw);
387                         break;
388
389                 case SSH_CMSG_PORT_FORWARD_REQUEST:
390                         if (no_port_forwarding_flag) {
391                                 debug("Port forwarding not permitted for this authentication.");
392                                 break;
393                         }
394                         if (!options.allow_tcp_forwarding) {
395                                 debug("Port forwarding not permitted.");
396                                 break;
397                         }
398                         debug("Received TCP/IP port forwarding request.");
399                         channel_input_port_forward_request(pw->pw_uid == 0, options.gateway_ports);
400                         success = 1;
401                         break;
402
403                 case SSH_CMSG_MAX_PACKET_SIZE:
404                         if (packet_set_maxsize(packet_get_int()) > 0)
405                                 success = 1;
406                         break;
407
408                 case SSH_CMSG_EXEC_SHELL:
409                 case SSH_CMSG_EXEC_CMD:
410                         /* Set interactive/non-interactive mode. */
411                         packet_set_interactive(have_pty || s->display != NULL,
412                             options.keepalives);
413
414                         if (type == SSH_CMSG_EXEC_CMD) {
415                                 command = packet_get_string(&dlen);
416                                 debug("Exec command '%.500s'", command);
417                                 packet_integrity_check(plen, 4 + dlen, type);
418                         } else {
419                                 command = NULL;
420                                 packet_integrity_check(plen, 0, type);
421                         }
422                         if (forced_command != NULL) {
423                                 original_command = command;
424                                 command = forced_command;
425                                 debug("Forced command '%.500s'", forced_command);
426                         }
427                         if (have_pty)
428                                 do_exec_pty(s, command, pw);
429                         else
430                                 do_exec_no_pty(s, command, pw);
431
432                         if (command != NULL)
433                                 xfree(command);
434                         /* Cleanup user's local Xauthority file. */
435                         if (xauthfile)
436                                 xauthfile_cleanup_proc(NULL);
437                         return;
438
439                 default:
440                         /*
441                          * Any unknown messages in this phase are ignored,
442                          * and a failure message is returned.
443                          */
444                         log("Unknown packet type received after authentication: %d", type);
445                 }
446                 packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE);
447                 packet_send();
448                 packet_write_wait();
449
450                 /* Enable compression now that we have replied if appropriate. */
451                 if (enable_compression_after_reply) {
452                         enable_compression_after_reply = 0;
453                         packet_start_compression(compression_level);
454                 }
455         }
456 }
457
458 /*
459  * This is called to fork and execute a command when we have no tty.  This
460  * will call do_child from the child, and server_loop from the parent after
461  * setting up file descriptors and such.
462  */
463 void
464 do_exec_no_pty(Session *s, const char *command, struct passwd * pw)
465 {
466         int pid;
467
468 #ifdef USE_PIPES
469         int pin[2], pout[2], perr[2];
470         /* Allocate pipes for communicating with the program. */
471         if (pipe(pin) < 0 || pipe(pout) < 0 || pipe(perr) < 0)
472                 packet_disconnect("Could not create pipes: %.100s",
473                                   strerror(errno));
474 #else /* USE_PIPES */
475         int inout[2], err[2];
476         /* Uses socket pairs to communicate with the program. */
477         if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0 ||
478             socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0)
479                 packet_disconnect("Could not create socket pairs: %.100s",
480                                   strerror(errno));
481 #endif /* USE_PIPES */
482         if (s == NULL)
483                 fatal("do_exec_no_pty: no session");
484
485         signal(SIGPIPE, SIG_DFL);
486
487         session_proctitle(s);
488
489 #ifdef USE_PAM
490                         do_pam_setcred();
491 #endif /* USE_PAM */
492
493         /* Fork the child. */
494         if ((pid = fork()) == 0) {
495                 /* Child.  Reinitialize the log since the pid has changed. */
496                 log_init(__progname, options.log_level, options.log_facility, log_stderr);
497
498                 /*
499                  * Create a new session and process group since the 4.4BSD
500                  * setlogin() affects the entire process group.
501                  */
502                 if (setsid() < 0)
503                         error("setsid failed: %.100s", strerror(errno));
504
505 #ifdef USE_PIPES
506                 /*
507                  * Redirect stdin.  We close the parent side of the socket
508                  * pair, and make the child side the standard input.
509                  */
510                 close(pin[1]);
511                 if (dup2(pin[0], 0) < 0)
512                         perror("dup2 stdin");
513                 close(pin[0]);
514
515                 /* Redirect stdout. */
516                 close(pout[0]);
517                 if (dup2(pout[1], 1) < 0)
518                         perror("dup2 stdout");
519                 close(pout[1]);
520
521                 /* Redirect stderr. */
522                 close(perr[0]);
523                 if (dup2(perr[1], 2) < 0)
524                         perror("dup2 stderr");
525                 close(perr[1]);
526 #else /* USE_PIPES */
527                 /*
528                  * Redirect stdin, stdout, and stderr.  Stdin and stdout will
529                  * use the same socket, as some programs (particularly rdist)
530                  * seem to depend on it.
531                  */
532                 close(inout[1]);
533                 close(err[1]);
534                 if (dup2(inout[0], 0) < 0)      /* stdin */
535                         perror("dup2 stdin");
536                 if (dup2(inout[0], 1) < 0)      /* stdout.  Note: same socket as stdin. */
537                         perror("dup2 stdout");
538                 if (dup2(err[0], 2) < 0)        /* stderr */
539                         perror("dup2 stderr");
540 #endif /* USE_PIPES */
541
542                 /* Do processing for the child (exec command etc). */
543                 do_child(command, pw, NULL, s->display, s->auth_proto, s->auth_data, NULL);
544                 /* NOTREACHED */
545         }
546 #ifdef HAVE_CYGWIN
547         if (is_winnt)
548                 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
549 #endif
550         if (pid < 0)
551                 packet_disconnect("fork failed: %.100s", strerror(errno));
552         s->pid = pid;
553 #ifdef USE_PIPES
554         /* We are the parent.  Close the child sides of the pipes. */
555         close(pin[0]);
556         close(pout[1]);
557         close(perr[1]);
558
559         if (compat20) {
560                 session_set_fds(s, pin[1], pout[0], s->extended ? perr[0] : -1);
561         } else {
562                 /* Enter the interactive session. */
563                 server_loop(pid, pin[1], pout[0], perr[0]);
564                 /* server_loop has closed pin[1], pout[1], and perr[1]. */
565         }
566 #else /* USE_PIPES */
567         /* We are the parent.  Close the child sides of the socket pairs. */
568         close(inout[0]);
569         close(err[0]);
570
571         /*
572          * Enter the interactive session.  Note: server_loop must be able to
573          * handle the case that fdin and fdout are the same.
574          */
575         if (compat20) {
576                 session_set_fds(s, inout[1], inout[1], s->extended ? err[1] : -1);
577         } else {
578                 server_loop(pid, inout[1], inout[1], err[1]);
579                 /* server_loop has closed inout[1] and err[1]. */
580         }
581 #endif /* USE_PIPES */
582 }
583
584 /*
585  * This is called to fork and execute a command when we have a tty.  This
586  * will call do_child from the child, and server_loop from the parent after
587  * setting up file descriptors, controlling tty, updating wtmp, utmp,
588  * lastlog, and other such operations.
589  */
590 void
591 do_exec_pty(Session *s, const char *command, struct passwd * pw)
592 {
593         int fdout, ptyfd, ttyfd, ptymaster;
594         pid_t pid;
595
596         if (s == NULL)
597                 fatal("do_exec_pty: no session");
598         ptyfd = s->ptyfd;
599         ttyfd = s->ttyfd;
600
601 #ifdef USE_PAM
602                         do_pam_session(pw->pw_name, s->tty);
603                         do_pam_setcred();
604 #endif /* USE_PAM */
605
606         /* Fork the child. */
607         if ((pid = fork()) == 0) {
608                 /* Child.  Reinitialize the log because the pid has changed. */
609                 log_init(__progname, options.log_level, options.log_facility, log_stderr);
610
611                 /* Close the master side of the pseudo tty. */
612                 close(ptyfd);
613
614                 /* Make the pseudo tty our controlling tty. */
615                 pty_make_controlling_tty(&ttyfd, s->tty);
616
617                 /* Redirect stdin from the pseudo tty. */
618                 if (dup2(ttyfd, fileno(stdin)) < 0)
619                         error("dup2 stdin failed: %.100s", strerror(errno));
620
621                 /* Redirect stdout to the pseudo tty. */
622                 if (dup2(ttyfd, fileno(stdout)) < 0)
623                         error("dup2 stdin failed: %.100s", strerror(errno));
624
625                 /* Redirect stderr to the pseudo tty. */
626                 if (dup2(ttyfd, fileno(stderr)) < 0)
627                         error("dup2 stdin failed: %.100s", strerror(errno));
628
629                 /* Close the extra descriptor for the pseudo tty. */
630                 close(ttyfd);
631
632                 /* record login, etc. similar to login(1) */
633                 if (!(options.use_login && command == NULL))
634                         do_login(s, command);
635
636                 /* Do common processing for the child, such as execing the command. */
637                 do_child(command, pw, s->term, s->display, s->auth_proto,
638                     s->auth_data, s->tty);
639                 /* NOTREACHED */
640         }
641 #ifdef HAVE_CYGWIN
642         if (is_winnt)
643                 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
644 #endif
645         if (pid < 0)
646                 packet_disconnect("fork failed: %.100s", strerror(errno));
647         s->pid = pid;
648
649         /* Parent.  Close the slave side of the pseudo tty. */
650         close(ttyfd);
651
652         /*
653          * Create another descriptor of the pty master side for use as the
654          * standard input.  We could use the original descriptor, but this
655          * simplifies code in server_loop.  The descriptor is bidirectional.
656          */
657         fdout = dup(ptyfd);
658         if (fdout < 0)
659                 packet_disconnect("dup #1 failed: %.100s", strerror(errno));
660
661         /* we keep a reference to the pty master */
662         ptymaster = dup(ptyfd);
663         if (ptymaster < 0)
664                 packet_disconnect("dup #2 failed: %.100s", strerror(errno));
665         s->ptymaster = ptymaster;
666
667         /* Enter interactive session. */
668         if (compat20) {
669                 session_set_fds(s, ptyfd, fdout, -1);
670         } else {
671                 server_loop(pid, ptyfd, fdout, -1);
672                 /* server_loop _has_ closed ptyfd and fdout. */
673                 session_pty_cleanup(s);
674         }
675 }
676
677 const char *
678 get_remote_name_or_ip(void)
679 {
680         static const char *remote = "";
681         if (utmp_len > 0)
682                 remote = get_canonical_hostname();
683         if (utmp_len == 0 || strlen(remote) > utmp_len)
684                 remote = get_remote_ipaddr();
685         return remote;
686 }
687
688 /* administrative, login(1)-like work */
689 void
690 do_login(Session *s, const char *command)
691 {
692         FILE *f;
693         char *time_string;
694         char buf[256];
695         char hostname[MAXHOSTNAMELEN];
696         socklen_t fromlen;
697         struct sockaddr_storage from;
698         struct stat st;
699         time_t last_login_time;
700         struct passwd * pw = s->pw;
701         pid_t pid = getpid();
702
703         /*
704          * Get IP address of client. If the connection is not a socket, let
705          * the address be 0.0.0.0.
706          */
707         memset(&from, 0, sizeof(from));
708         if (packet_connection_is_on_socket()) {
709                 fromlen = sizeof(from);
710                 if (getpeername(packet_get_connection_in(),
711                      (struct sockaddr *) & from, &fromlen) < 0) {
712                         debug("getpeername: %.100s", strerror(errno));
713                         fatal_cleanup();
714                 }
715         }
716
717         /* Get the time and hostname when the user last logged in. */
718         hostname[0] = '\0';
719         last_login_time = get_last_login_time(pw->pw_uid, pw->pw_name,
720             hostname, sizeof(hostname));
721
722         /* Record that there was a login on that tty from the remote host. */
723         record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
724             get_remote_name_or_ip(), (struct sockaddr *)&from);
725
726 #ifdef USE_PAM
727         /*
728          * If password change is needed, do it now.
729          * This needs to occur before the ~/.hushlogin check.
730          */
731         if (pam_password_change_required()) {
732                 print_pam_messages();
733                 do_pam_chauthtok();
734         }
735 #endif
736
737         /* Done if .hushlogin exists or a command given. */
738         if (command != NULL)
739                 return;
740         snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
741 #ifdef HAVE_LOGIN_CAP
742         if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
743 #else
744         if (stat(buf, &st) >= 0)
745 #endif
746                 return;
747
748 #ifdef USE_PAM
749         if (!pam_password_change_required())
750                 print_pam_messages();
751 #endif /* USE_PAM */
752 #ifdef WITH_AIXAUTHENTICATE
753         if (aixloginmsg && *aixloginmsg)
754                 printf("%s\n", aixloginmsg);
755 #endif /* WITH_AIXAUTHENTICATE */
756
757         if (last_login_time != 0) {
758                 time_string = ctime(&last_login_time);
759                 if (strchr(time_string, '\n'))
760                         *strchr(time_string, '\n') = 0;
761                 if (strcmp(hostname, "") == 0)
762                         printf("Last login: %s\r\n", time_string);
763                 else
764                         printf("Last login: %s from %s\r\n", time_string, hostname);
765         }
766         if (options.print_motd) {
767 #ifdef HAVE_LOGIN_CAP
768                 f = fopen(login_getcapstr(lc, "welcome", "/etc/motd",
769                     "/etc/motd"), "r");
770 #else
771                 f = fopen("/etc/motd", "r");
772 #endif
773                 if (f) {
774                         while (fgets(buf, sizeof(buf), f))
775                                 fputs(buf, stdout);
776                         fclose(f);
777                 }
778         }
779 }
780
781 /*
782  * Sets the value of the given variable in the environment.  If the variable
783  * already exists, its value is overriden.
784  */
785 void
786 child_set_env(char ***envp, unsigned int *envsizep, const char *name,
787               const char *value)
788 {
789         unsigned int i, namelen;
790         char **env;
791
792         /*
793          * Find the slot where the value should be stored.  If the variable
794          * already exists, we reuse the slot; otherwise we append a new slot
795          * at the end of the array, expanding if necessary.
796          */
797         env = *envp;
798         namelen = strlen(name);
799         for (i = 0; env[i]; i++)
800                 if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
801                         break;
802         if (env[i]) {
803                 /* Reuse the slot. */
804                 xfree(env[i]);
805         } else {
806                 /* New variable.  Expand if necessary. */
807                 if (i >= (*envsizep) - 1) {
808                         (*envsizep) += 50;
809                         env = (*envp) = xrealloc(env, (*envsizep) * sizeof(char *));
810                 }
811                 /* Need to set the NULL pointer at end of array beyond the new slot. */
812                 env[i + 1] = NULL;
813         }
814
815         /* Allocate space and format the variable in the appropriate slot. */
816         env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
817         snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
818 }
819
820 /*
821  * Reads environment variables from the given file and adds/overrides them
822  * into the environment.  If the file does not exist, this does nothing.
823  * Otherwise, it must consist of empty lines, comments (line starts with '#')
824  * and assignments of the form name=value.  No other forms are allowed.
825  */
826 void
827 read_environment_file(char ***env, unsigned int *envsize,
828                       const char *filename)
829 {
830         FILE *f;
831         char buf[4096];
832         char *cp, *value;
833
834         f = fopen(filename, "r");
835         if (!f)
836                 return;
837
838         while (fgets(buf, sizeof(buf), f)) {
839                 for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
840                         ;
841                 if (!*cp || *cp == '#' || *cp == '\n')
842                         continue;
843                 if (strchr(cp, '\n'))
844                         *strchr(cp, '\n') = '\0';
845                 value = strchr(cp, '=');
846                 if (value == NULL) {
847                         fprintf(stderr, "Bad line in %.100s: %.200s\n", filename, buf);
848                         continue;
849                 }
850                 /*
851                  * Replace the equals sign by nul, and advance value to
852                  * the value string.
853                  */
854                 *value = '\0';
855                 value++;
856                 child_set_env(env, envsize, cp, value);
857         }
858         fclose(f);
859 }
860
861 #ifdef USE_PAM
862 /*
863  * Sets any environment variables which have been specified by PAM
864  */
865 void do_pam_environment(char ***env, int *envsize)
866 {
867         char *equals, var_name[512], var_val[512];
868         char **pam_env;
869         int i;
870
871         if ((pam_env = fetch_pam_environment()) == NULL)
872                 return;
873         
874         for(i = 0; pam_env[i] != NULL; i++) {
875                 if ((equals = strstr(pam_env[i], "=")) == NULL)
876                         continue;
877                         
878                 if (strlen(pam_env[i]) < (sizeof(var_name) - 1)) {
879                         memset(var_name, '\0', sizeof(var_name));
880                         memset(var_val, '\0', sizeof(var_val));
881
882                         strncpy(var_name, pam_env[i], equals - pam_env[i]);
883                         strcpy(var_val, equals + 1);
884
885                         debug3("PAM environment: %s=%s", var_name, var_val);
886
887                         child_set_env(env, envsize, var_name, var_val);
888                 }
889         }
890 }
891 #endif /* USE_PAM */
892
893
894 #ifdef HAVE_CYGWIN
895 void copy_environment(char ***env, int *envsize)
896 {
897         char *equals, var_name[512], var_val[512];
898         int i;
899
900         for(i = 0; environ[i] != NULL; i++) {
901                 if ((equals = strstr(environ[i], "=")) == NULL)
902                         continue;
903                         
904                 if (strlen(environ[i]) < (sizeof(var_name) - 1)) {
905                         memset(var_name, '\0', sizeof(var_name));
906                         memset(var_val, '\0', sizeof(var_val));
907
908                         strncpy(var_name, environ[i], equals - environ[i]);
909                         strcpy(var_val, equals + 1);
910
911                         debug3("Copy environment: %s=%s", var_name, var_val);
912
913                         child_set_env(env, envsize, var_name, var_val);
914                 }
915         }
916 }
917 #endif
918
919 #if defined(HAVE_GETUSERATTR)
920 /*
921  * AIX-specific login initialisation
922  */
923 void set_limit(char *user, char *soft, char *hard, int resource, int mult)
924 {
925         struct rlimit rlim;
926         int slim, hlim;
927
928         getrlimit(resource, &rlim);
929
930         slim = 0;
931         if (getuserattr(user, soft, &slim, SEC_INT) != -1) {
932                 if (slim < 0) {
933                         rlim.rlim_cur = RLIM_INFINITY;
934                 } else if (slim != 0) {
935                         /* See the wackiness below */
936                         if (rlim.rlim_cur == slim * mult)
937                                 slim = 0;
938                         else
939                                 rlim.rlim_cur = slim * mult;
940                 }
941         }
942
943         hlim = 0;
944         if (getuserattr(user, hard, &hlim, SEC_INT) != -1) {
945                 if (hlim < 0) {
946                         rlim.rlim_max = RLIM_INFINITY;
947                 } else if (hlim != 0) {
948                         rlim.rlim_max = hlim * mult;
949                 }
950         }
951
952         /*
953          * XXX For cpu and fsize the soft limit is set to the hard limit
954          * if the hard limit is left at its default value and the soft limit
955          * is changed from its default value, either by requesting it
956          * (slim == 0) or by setting it to the current default.  At least
957          * that's how rlogind does it.  If you're confused you're not alone.
958          * Bug or feature? AIX 4.3.1.2
959          */
960         if ((!strcmp(soft, "fsize") || !strcmp(soft, "cpu"))
961             && hlim == 0 && slim != 0)
962                 rlim.rlim_max = rlim.rlim_cur;
963         /* A specified hard limit limits the soft limit */
964         else if (hlim > 0 && rlim.rlim_cur > rlim.rlim_max)
965                 rlim.rlim_cur = rlim.rlim_max;
966         /* A soft limit can increase a hard limit */
967         else if (rlim.rlim_cur > rlim.rlim_max)
968                 rlim.rlim_max = rlim.rlim_cur;
969
970         if (setrlimit(resource, &rlim) != 0)
971                 error("setrlimit(%.10s) failed: %.100s", soft, strerror(errno));
972 }
973
974 void set_limits_from_userattr(char *user)
975 {
976         int mask;
977         char buf[16];
978
979         set_limit(user, S_UFSIZE, S_UFSIZE_HARD, RLIMIT_FSIZE, 512);
980         set_limit(user, S_UCPU, S_UCPU_HARD, RLIMIT_CPU, 1);
981         set_limit(user, S_UDATA, S_UDATA_HARD, RLIMIT_DATA, 512);
982         set_limit(user, S_USTACK, S_USTACK_HARD, RLIMIT_STACK, 512);
983         set_limit(user, S_URSS, S_URSS_HARD, RLIMIT_RSS, 512);
984         set_limit(user, S_UCORE, S_UCORE_HARD, RLIMIT_CORE, 512);
985 #if defined(S_UNOFILE)
986         set_limit(user, S_UNOFILE, S_UNOFILE_HARD, RLIMIT_NOFILE, 1);
987 #endif
988
989         if (getuserattr(user, S_UMASK, &mask, SEC_INT) != -1) {
990                 /* Convert decimal to octal */
991                 (void) snprintf(buf, sizeof(buf), "%d", mask);
992                 if (sscanf(buf, "%o", &mask) == 1)
993                         umask(mask);
994         }
995 }
996 #endif /* defined(HAVE_GETUSERATTR) */
997
998 /*
999  * Performs common processing for the child, such as setting up the
1000  * environment, closing extra file descriptors, setting the user and group
1001  * ids, and executing the command or shell.
1002  */
1003 void
1004 do_child(const char *command, struct passwd * pw, const char *term,
1005          const char *display, const char *auth_proto,
1006          const char *auth_data, const char *ttyname)
1007 {
1008         const char *shell, *hostname = NULL, *cp = NULL;
1009         char buf[256];
1010         char cmd[1024];
1011         FILE *f = NULL;
1012         unsigned int envsize, i;
1013         char **env;
1014         extern char **environ;
1015         struct stat st;
1016         char *argv[10];
1017 #ifdef WITH_IRIX_PROJECT
1018         prid_t projid;
1019 #endif /* WITH_IRIX_PROJECT */
1020 #ifdef WITH_IRIX_JOBS
1021         jid_t jid = 0;
1022 #else
1023 #ifdef WITH_IRIX_ARRAY
1024         int jid = 0;
1025 #endif /* WITH_IRIX_ARRAY */
1026 #endif /* WITH_IRIX_JOBS */
1027
1028
1029         /* login(1) is only called if we execute the login shell */
1030         if (options.use_login && command != NULL)
1031                 options.use_login = 0;
1032
1033 #ifndef USE_PAM /* pam_nologin handles this */
1034         if (!options.use_login) {
1035 # ifdef HAVE_LOGIN_CAP
1036                 if (!login_getcapbool(lc, "ignorenologin", 0) && pw->pw_uid)
1037                         f = fopen(login_getcapstr(lc, "nologin", _PATH_NOLOGIN,
1038                             _PATH_NOLOGIN), "r");
1039 # else /* HAVE_LOGIN_CAP */
1040                 if (pw->pw_uid)
1041                         f = fopen(_PATH_NOLOGIN, "r");
1042 # endif /* HAVE_LOGIN_CAP */
1043                 if (f) {
1044                         /* /etc/nologin exists.  Print its contents and exit. */
1045                         while (fgets(buf, sizeof(buf), f))
1046                                 fputs(buf, stderr);
1047                         fclose(f);
1048                         exit(254);
1049                 }
1050         }
1051 #endif /* USE_PAM */
1052
1053         /* Set login name, uid, gid, and groups. */
1054         /* Login(1) does this as well, and it needs uid 0 for the "-h"
1055            switch, so we let login(1) to this for us. */
1056         if (!options.use_login) {
1057 #ifdef HAVE_OSF_SIA
1058                 extern char **saved_argv;
1059                 extern int saved_argc;
1060                 char *host = get_canonical_hostname ();
1061
1062                 if (sia_become_user(NULL, saved_argc, saved_argv, host,
1063                     pw->pw_name, ttyname, 0, NULL, NULL, SIA_BEU_SETLUID) !=
1064                     SIASUCCESS) {
1065                         perror("sia_become_user");
1066                         exit(1);
1067                 }
1068                 if (setreuid(geteuid(), geteuid()) < 0) {
1069                         perror("setreuid");
1070                         exit(1);
1071                 }
1072 #else /* HAVE_OSF_SIA */
1073 #ifdef HAVE_CYGWIN
1074                 if (is_winnt) {
1075 #else
1076                 if (getuid() == 0 || geteuid() == 0) {
1077 #endif
1078 # ifdef HAVE_GETUSERATTR
1079                         set_limits_from_userattr(pw->pw_name);
1080 # endif /* HAVE_GETUSERATTR */
1081 # ifdef HAVE_LOGIN_CAP
1082                         if (setusercontext(lc, pw, pw->pw_uid,
1083                             (LOGIN_SETALL & ~LOGIN_SETPATH)) < 0) {
1084                                 perror("unable to set user context");
1085                                 exit(1);
1086                         }
1087 # else /* HAVE_LOGIN_CAP */
1088                         if (setlogin(pw->pw_name) < 0)
1089                                 error("setlogin failed: %s", strerror(errno));
1090                         if (setgid(pw->pw_gid) < 0) {
1091                                 perror("setgid");
1092                                 exit(1);
1093                         }
1094                         /* Initialize the group list. */
1095                         if (initgroups(pw->pw_name, pw->pw_gid) < 0) {
1096                                 perror("initgroups");
1097                                 exit(1);
1098                         }
1099                         endgrent();
1100 #  ifdef WITH_IRIX_JOBS
1101                         jid = jlimit_startjob(pw->pw_name, pw->pw_uid, "interactive");
1102                         if (jid == -1) {
1103                                 fatal("Failed to create job container: %.100s",
1104                                       strerror(errno));
1105                         }
1106 #  endif /* WITH_IRIX_JOBS */
1107
1108 #  ifdef WITH_IRIX_ARRAY
1109                         /* initialize array session */
1110                         if (jid == 0) {
1111                                 if (newarraysess() != 0)
1112                                         fatal("Failed to set up new array session: %.100s",
1113                                               strerror(errno));
1114                         }
1115 #  endif /* WITH_IRIX_ARRAY */
1116 #  ifdef WITH_IRIX_PROJECT
1117                         /* initialize irix project info */
1118                         if ((projid = getdfltprojuser(pw->pw_name)) == -1) {
1119                           debug("Failed to get project id, using projid 0");
1120                           projid = 0;
1121                         }
1122                         if (setprid(projid))
1123                           fatal("Failed to initialize project %d for %s: %.100s",
1124                                 (int)projid, pw->pw_name, strerror(errno));
1125 #  endif /* WITH_IRIX_PROJECT */
1126                         /* Permanently switch to the desired uid. */
1127                         permanently_set_uid(pw->pw_uid);
1128 # endif /* HAVE_LOGIN_CAP */
1129                 }
1130 #endif /* HAVE_OSF_SIA */
1131
1132 #ifdef HAVE_CYGWIN
1133                 if (is_winnt)
1134 #endif
1135                 if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
1136                         fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
1137         }
1138         /*
1139          * Get the shell from the password data.  An empty shell field is
1140          * legal, and means /bin/sh.
1141          */
1142         shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1143 #ifdef HAVE_LOGIN_CAP
1144         shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
1145 #endif
1146
1147 #ifdef AFS
1148         /* Try to get AFS tokens for the local cell. */
1149         if (k_hasafs()) {
1150                 char cell[64];
1151
1152                 if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
1153                         krb_afslog(cell, 0);
1154
1155                 krb_afslog(0, 0);
1156         }
1157 #endif /* AFS */
1158
1159         /* Initialize the environment. */
1160         envsize = 100;
1161         env = xmalloc(envsize * sizeof(char *));
1162         env[0] = NULL;
1163
1164 #ifdef HAVE_CYGWIN
1165         /*
1166          * The Windows environment contains some setting which are
1167          * important for a running system. They must not be dropped.
1168          */
1169         copy_environment(&env, &envsize);
1170 #endif
1171
1172         if (!options.use_login) {
1173                 /* Set basic environment. */
1174                 child_set_env(&env, &envsize, "USER", pw->pw_name);
1175                 child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
1176                 child_set_env(&env, &envsize, "HOME", pw->pw_dir);
1177 #ifdef HAVE_LOGIN_CAP
1178                 (void) setusercontext(lc, pw, pw->pw_uid, LOGIN_SETPATH);
1179                 child_set_env(&env, &envsize, "PATH", getenv("PATH"));
1180 #else /* HAVE_LOGIN_CAP */
1181 # ifndef HAVE_CYGWIN
1182                 /*
1183                  * There's no standard path on Windows. The path contains
1184                  * important components pointing to the system directories,
1185                  * needed for loading shared libraries. So the path better
1186                  * remains intact here.
1187                  */
1188                 child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
1189 # endif /* HAVE_CYGWIN */
1190 #endif /* HAVE_LOGIN_CAP */
1191
1192                 snprintf(buf, sizeof buf, "%.200s/%.50s",
1193                          _PATH_MAILDIR, pw->pw_name);
1194                 child_set_env(&env, &envsize, "MAIL", buf);
1195
1196                 /* Normal systems set SHELL by default. */
1197                 child_set_env(&env, &envsize, "SHELL", shell);
1198         }
1199         if (getenv("TZ"))
1200                 child_set_env(&env, &envsize, "TZ", getenv("TZ"));
1201
1202         /* Set custom environment options from RSA authentication. */
1203         while (custom_environment) {
1204                 struct envstring *ce = custom_environment;
1205                 char *s = ce->s;
1206                 int i;
1207                 for (i = 0; s[i] != '=' && s[i]; i++);
1208                 if (s[i] == '=') {
1209                         s[i] = 0;
1210                         child_set_env(&env, &envsize, s, s + i + 1);
1211                 }
1212                 custom_environment = ce->next;
1213                 xfree(ce->s);
1214                 xfree(ce);
1215         }
1216
1217         snprintf(buf, sizeof buf, "%.50s %d %d",
1218                  get_remote_ipaddr(), get_remote_port(), get_local_port());
1219         child_set_env(&env, &envsize, "SSH_CLIENT", buf);
1220
1221         if (ttyname)
1222                 child_set_env(&env, &envsize, "SSH_TTY", ttyname);
1223         if (term)
1224                 child_set_env(&env, &envsize, "TERM", term);
1225         if (display)
1226                 child_set_env(&env, &envsize, "DISPLAY", display);
1227         if (original_command)
1228                 child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
1229                     original_command);
1230
1231 #ifdef _AIX
1232         if ((cp = getenv("AUTHSTATE")) != NULL)
1233                 child_set_env(&env, &envsize, "AUTHSTATE", cp);
1234         if ((cp = getenv("KRB5CCNAME")) != NULL)
1235                 child_set_env(&env, &envsize, "KRB5CCNAME", cp);
1236         read_environment_file(&env, &envsize, "/etc/environment");
1237 #endif
1238
1239 #ifdef KRB4
1240         {
1241                 extern char *ticket;
1242
1243                 if (ticket)
1244                         child_set_env(&env, &envsize, "KRBTKFILE", ticket);
1245         }
1246 #endif /* KRB4 */
1247
1248 #ifdef USE_PAM
1249         /* Pull in any environment variables that may have been set by PAM. */
1250         do_pam_environment(&env, &envsize);
1251 #endif /* USE_PAM */
1252
1253         if (xauthfile)
1254                 child_set_env(&env, &envsize, "XAUTHORITY", xauthfile);
1255         if (auth_get_socket_name() != NULL)
1256                 child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
1257                               auth_get_socket_name());
1258
1259         /* read $HOME/.ssh/environment. */
1260         if (!options.use_login) {
1261                 snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
1262                     pw->pw_dir);
1263                 read_environment_file(&env, &envsize, buf);
1264         }
1265         if (debug_flag) {
1266                 /* dump the environment */
1267                 fprintf(stderr, "Environment:\n");
1268                 for (i = 0; env[i]; i++)
1269                         fprintf(stderr, "  %.200s\n", env[i]);
1270         }
1271         /* we have to stash the hostname before we close our socket. */
1272         if (options.use_login)
1273                 hostname = get_remote_name_or_ip();
1274         /*
1275          * Close the connection descriptors; note that this is the child, and
1276          * the server will still have the socket open, and it is important
1277          * that we do not shutdown it.  Note that the descriptors cannot be
1278          * closed before building the environment, as we call
1279          * get_remote_ipaddr there.
1280          */
1281         if (packet_get_connection_in() == packet_get_connection_out())
1282                 close(packet_get_connection_in());
1283         else {
1284                 close(packet_get_connection_in());
1285                 close(packet_get_connection_out());
1286         }
1287         /*
1288          * Close all descriptors related to channels.  They will still remain
1289          * open in the parent.
1290          */
1291         /* XXX better use close-on-exec? -markus */
1292         channel_close_all();
1293
1294         /*
1295          * Close any extra file descriptors.  Note that there may still be
1296          * descriptors left by system functions.  They will be closed later.
1297          */
1298         endpwent();
1299
1300         /*
1301          * Close any extra open file descriptors so that we don\'t have them
1302          * hanging around in clients.  Note that we want to do this after
1303          * initgroups, because at least on Solaris 2.3 it leaves file
1304          * descriptors open.
1305          */
1306         for (i = 3; i < 64; i++)
1307                 close(i);
1308
1309         /* Change current directory to the user\'s home directory. */
1310         if (chdir(pw->pw_dir) < 0) {
1311                 fprintf(stderr, "Could not chdir to home directory %s: %s\n",
1312                         pw->pw_dir, strerror(errno));
1313 #ifdef HAVE_LOGIN_CAP
1314                 if (login_getcapbool(lc, "requirehome", 0))
1315                         exit(1);
1316 #endif
1317         }
1318
1319         /*
1320          * Must take new environment into use so that .ssh/rc, /etc/sshrc and
1321          * xauth are run in the proper environment.
1322          */
1323         environ = env;
1324
1325         /*
1326          * Run $HOME/.ssh/rc, /etc/sshrc, or xauth (whichever is found first
1327          * in this order).
1328          */
1329         if (!options.use_login) {
1330                 if (stat(SSH_USER_RC, &st) >= 0) {
1331                         if (debug_flag)
1332                                 fprintf(stderr, "Running "_PATH_BSHELL" %s\n", SSH_USER_RC);
1333
1334                         f = popen(_PATH_BSHELL " " SSH_USER_RC, "w");
1335                         if (f) {
1336                                 if (auth_proto != NULL && auth_data != NULL)
1337                                         fprintf(f, "%s %s\n", auth_proto, auth_data);
1338                                 pclose(f);
1339                         } else
1340                                 fprintf(stderr, "Could not run %s\n", SSH_USER_RC);
1341                 } else if (stat(SSH_SYSTEM_RC, &st) >= 0) {
1342                         if (debug_flag)
1343                                 fprintf(stderr, "Running "_PATH_BSHELL" %s\n", SSH_SYSTEM_RC);
1344
1345                         f = popen(_PATH_BSHELL " " SSH_SYSTEM_RC, "w");
1346                         if (f) {
1347                                 if (auth_proto != NULL && auth_data != NULL)
1348                                         fprintf(f, "%s %s\n", auth_proto, auth_data);
1349                                 pclose(f);
1350                         } else
1351                                 fprintf(stderr, "Could not run %s\n", SSH_SYSTEM_RC);
1352                 } else if (options.xauth_location != NULL) {
1353                         /* Add authority data to .Xauthority if appropriate. */
1354                         if (auth_proto != NULL && auth_data != NULL) {
1355                                 char *screen = strchr(display, ':');
1356                                 if (debug_flag) {
1357                                         fprintf(stderr,
1358                                             "Running %.100s add %.100s %.100s %.100s\n",
1359                                             options.xauth_location, display,
1360                                             auth_proto, auth_data);
1361 #ifndef HAVE_CYGWIN /* Unix sockets are not supported */
1362                                         if (screen != NULL)
1363                                                 fprintf(stderr,
1364                                                     "Adding %.*s/unix%s %s %s\n",
1365                                                     (int)(screen-display), display,
1366                                                     screen, auth_proto, auth_data);
1367 #endif
1368                                 }
1369                                 snprintf(cmd, sizeof cmd, "%s -q -",
1370                                     options.xauth_location);
1371                                 f = popen(cmd, "w");
1372                                 if (f) {
1373                                         fprintf(f, "add %s %s %s\n", display,
1374                                             auth_proto, auth_data);
1375 #ifndef HAVE_CYGWIN /* Unix sockets are not supported */
1376                                         if (screen != NULL) 
1377                                                 fprintf(f, "add %.*s/unix%s %s %s\n",
1378                                                     (int)(screen-display), display,
1379                                                     screen, auth_proto, auth_data);
1380 #endif
1381                                         pclose(f);
1382                                 } else {
1383                                         fprintf(stderr, "Could not run %s\n",
1384                                             cmd);
1385                                 }
1386                         }
1387                 }
1388                 /* Get the last component of the shell name. */
1389                 cp = strrchr(shell, '/');
1390                 if (cp)
1391                         cp++;
1392                 else
1393                         cp = shell;
1394         }
1395         /*
1396          * If we have no command, execute the shell.  In this case, the shell
1397          * name to be passed in argv[0] is preceded by '-' to indicate that
1398          * this is a login shell.
1399          */
1400         if (!command) {
1401                 if (!options.use_login) {
1402                         char buf[256];
1403
1404                         /*
1405                          * Check for mail if we have a tty and it was enabled
1406                          * in server options.
1407                          */
1408                         if (ttyname && options.check_mail) {
1409                                 char *mailbox;
1410                                 struct stat mailstat;
1411                                 mailbox = getenv("MAIL");
1412                                 if (mailbox != NULL) {
1413                                         if (stat(mailbox, &mailstat) != 0 ||
1414                                             mailstat.st_size == 0)
1415                                                 printf("No mail.\n");
1416                                         else if (mailstat.st_mtime < mailstat.st_atime)
1417                                                 printf("You have mail.\n");
1418                                         else
1419                                                 printf("You have new mail.\n");
1420                                 }
1421                         }
1422                         /* Start the shell.  Set initial character to '-'. */
1423                         buf[0] = '-';
1424                         strncpy(buf + 1, cp, sizeof(buf) - 1);
1425                         buf[sizeof(buf) - 1] = 0;
1426
1427                         /* Execute the shell. */
1428                         argv[0] = buf;
1429                         argv[1] = NULL;
1430                         execve(shell, argv, env);
1431
1432                         /* Executing the shell failed. */
1433                         perror(shell);
1434                         exit(1);
1435
1436                 } else {
1437                         /* Launch login(1). */
1438
1439                         execl(LOGIN_PROGRAM, "login", "-h", hostname,
1440                              "-p", "-f", "--", pw->pw_name, NULL);
1441
1442                         /* Login couldn't be executed, die. */
1443
1444                         perror("login");
1445                         exit(1);
1446                 }
1447         }
1448         /*
1449          * Execute the command using the user's shell.  This uses the -c
1450          * option to execute the command.
1451          */
1452         argv[0] = (char *) cp;
1453         argv[1] = "-c";
1454         argv[2] = (char *) command;
1455         argv[3] = NULL;
1456         execve(shell, argv, env);
1457         perror(shell);
1458         exit(1);
1459 }
1460
1461 Session *
1462 session_new(void)
1463 {
1464         int i;
1465         static int did_init = 0;
1466         if (!did_init) {
1467                 debug("session_new: init");
1468                 for(i = 0; i < MAX_SESSIONS; i++) {
1469                         sessions[i].used = 0;
1470                         sessions[i].self = i;
1471                 }
1472                 did_init = 1;
1473         }
1474         for(i = 0; i < MAX_SESSIONS; i++) {
1475                 Session *s = &sessions[i];
1476                 if (! s->used) {
1477                         s->pid = 0;
1478                         s->extended = 0;
1479                         s->chanid = -1;
1480                         s->ptyfd = -1;
1481                         s->ttyfd = -1;
1482                         s->term = NULL;
1483                         s->pw = NULL;
1484                         s->display = NULL;
1485                         s->screen = 0;
1486                         s->auth_data = NULL;
1487                         s->auth_proto = NULL;
1488                         s->used = 1;
1489                         s->pw = NULL;
1490                         debug("session_new: session %d", i);
1491                         return s;
1492                 }
1493         }
1494         return NULL;
1495 }
1496
1497 void
1498 session_dump(void)
1499 {
1500         int i;
1501         for(i = 0; i < MAX_SESSIONS; i++) {
1502                 Session *s = &sessions[i];
1503                 debug("dump: used %d session %d %p channel %d pid %d",
1504                     s->used,
1505                     s->self,
1506                     s,
1507                     s->chanid,
1508                     s->pid);
1509         }
1510 }
1511
1512 int
1513 session_open(int chanid)
1514 {
1515         Session *s = session_new();
1516         debug("session_open: channel %d", chanid);
1517         if (s == NULL) {
1518                 error("no more sessions");
1519                 return 0;
1520         }
1521         s->pw = auth_get_user();
1522         if (s->pw == NULL)
1523                 fatal("no user for session %i", s->self);
1524         debug("session_open: session %d: link with channel %d", s->self, chanid);
1525         s->chanid = chanid;
1526         return 1;
1527 }
1528
1529 Session *
1530 session_by_channel(int id)
1531 {
1532         int i;
1533         for(i = 0; i < MAX_SESSIONS; i++) {
1534                 Session *s = &sessions[i];
1535                 if (s->used && s->chanid == id) {
1536                         debug("session_by_channel: session %d channel %d", i, id);
1537                         return s;
1538                 }
1539         }
1540         debug("session_by_channel: unknown channel %d", id);
1541         session_dump();
1542         return NULL;
1543 }
1544
1545 Session *
1546 session_by_pid(pid_t pid)
1547 {
1548         int i;
1549         debug("session_by_pid: pid %d", pid);
1550         for(i = 0; i < MAX_SESSIONS; i++) {
1551                 Session *s = &sessions[i];
1552                 if (s->used && s->pid == pid)
1553                         return s;
1554         }
1555         error("session_by_pid: unknown pid %d", pid);
1556         session_dump();
1557         return NULL;
1558 }
1559
1560 int
1561 session_window_change_req(Session *s)
1562 {
1563         s->col = packet_get_int();
1564         s->row = packet_get_int();
1565         s->xpixel = packet_get_int();
1566         s->ypixel = packet_get_int();
1567         packet_done();
1568         pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1569         return 1;
1570 }
1571
1572 int
1573 session_pty_req(Session *s)
1574 {
1575         unsigned int len;
1576         char *term_modes;       /* encoded terminal modes */
1577
1578         if (no_pty_flag)
1579                 return 0;
1580         if (s->ttyfd != -1)
1581                 return 0;
1582         s->term = packet_get_string(&len);
1583         s->col = packet_get_int();
1584         s->row = packet_get_int();
1585         s->xpixel = packet_get_int();
1586         s->ypixel = packet_get_int();
1587         term_modes = packet_get_string(&len);
1588         packet_done();
1589
1590         if (strcmp(s->term, "") == 0) {
1591                 xfree(s->term);
1592                 s->term = NULL;
1593         }
1594         /* Allocate a pty and open it. */
1595         if (!pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty))) {
1596                 xfree(s->term);
1597                 s->term = NULL;
1598                 s->ptyfd = -1;
1599                 s->ttyfd = -1;
1600                 error("session_pty_req: session %d alloc failed", s->self);
1601                 xfree(term_modes);
1602                 return 0;
1603         }
1604         debug("session_pty_req: session %d alloc %s", s->self, s->tty);
1605         /*
1606          * Add a cleanup function to clear the utmp entry and record logout
1607          * time in case we call fatal() (e.g., the connection gets closed).
1608          */
1609         fatal_add_cleanup(pty_cleanup_proc, (void *)s);
1610         pty_setowner(s->pw, s->tty);
1611         /* Get window size from the packet. */
1612         pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1613
1614         session_proctitle(s);
1615
1616         /* XXX parse and set terminal modes */
1617         xfree(term_modes);
1618         return 1;
1619 }
1620
1621 int
1622 session_subsystem_req(Session *s)
1623 {
1624         unsigned int len;
1625         int success = 0;
1626         char *subsys = packet_get_string(&len);
1627         int i;
1628
1629         packet_done();
1630         log("subsystem request for %s", subsys);
1631
1632         for (i = 0; i < options.num_subsystems; i++) {
1633                 if(strcmp(subsys, options.subsystem_name[i]) == 0) {
1634                         debug("subsystem: exec() %s", options.subsystem_command[i]);
1635                         do_exec_no_pty(s, options.subsystem_command[i], s->pw);
1636                         success = 1;
1637                 }
1638         }
1639
1640         if (!success)
1641                 log("subsystem request for %s failed, subsystem not found", subsys);
1642
1643         xfree(subsys);
1644         return success;
1645 }
1646
1647 int
1648 session_x11_req(Session *s)
1649 {
1650         int fd;
1651         if (no_x11_forwarding_flag) {
1652                 debug("X11 forwarding disabled in user configuration file.");
1653                 return 0;
1654         }
1655         if (!options.x11_forwarding) {
1656                 debug("X11 forwarding disabled in server configuration file.");
1657                 return 0;
1658         }
1659         if (xauthfile != NULL) {
1660                 debug("X11 fwd already started.");
1661                 return 0;
1662         }
1663
1664         debug("Received request for X11 forwarding with auth spoofing.");
1665         if (s->display != NULL)
1666                 packet_disconnect("Protocol error: X11 display already set.");
1667
1668         s->single_connection = packet_get_char();
1669         s->auth_proto = packet_get_string(NULL);
1670         s->auth_data = packet_get_string(NULL);
1671         s->screen = packet_get_int();
1672         packet_done();
1673
1674         s->display = x11_create_display_inet(s->screen, options.x11_display_offset);
1675         if (s->display == NULL) {
1676                 xfree(s->auth_proto);
1677                 xfree(s->auth_data);
1678                 return 0;
1679         }
1680         xauthfile = xmalloc(MAXPATHLEN);
1681         strlcpy(xauthfile, "/tmp/ssh-XXXXXXXX", MAXPATHLEN);
1682         temporarily_use_uid(s->pw->pw_uid);
1683         if (mkdtemp(xauthfile) == NULL) {
1684                 restore_uid();
1685                 error("private X11 dir: mkdtemp %s failed: %s",
1686                     xauthfile, strerror(errno));
1687                 xfree(xauthfile);
1688                 xauthfile = NULL;
1689                 xfree(s->auth_proto);
1690                 xfree(s->auth_data);
1691                 /* XXXX remove listening channels */
1692                 return 0;
1693         }
1694         strlcat(xauthfile, "/cookies", MAXPATHLEN);
1695         fd = open(xauthfile, O_RDWR|O_CREAT|O_EXCL, 0600);
1696         if (fd >= 0)
1697                 close(fd);
1698         restore_uid();
1699         fatal_add_cleanup(xauthfile_cleanup_proc, s);
1700         return 1;
1701 }
1702
1703 int
1704 session_shell_req(Session *s)
1705 {
1706         /* if forced_command == NULL, the shell is execed */
1707         char *shell = forced_command;
1708         packet_done();
1709         s->extended = 1;
1710         if (s->ttyfd == -1)
1711                 do_exec_no_pty(s, shell, s->pw);
1712         else
1713                 do_exec_pty(s, shell, s->pw);
1714         return 1;
1715 }
1716
1717 int
1718 session_exec_req(Session *s)
1719 {
1720         unsigned int len;
1721         char *command = packet_get_string(&len);
1722         packet_done();
1723         if (forced_command) {
1724                 original_command = command;
1725                 command = forced_command;
1726                 debug("Forced command '%.500s'", forced_command);
1727         }
1728         s->extended = 1;
1729         if (s->ttyfd == -1)
1730                 do_exec_no_pty(s, command, s->pw);
1731         else
1732                 do_exec_pty(s, command, s->pw);
1733         if (forced_command == NULL)
1734                 xfree(command);
1735         return 1;
1736 }
1737
1738 int
1739 session_auth_agent_req(Session *s)
1740 {
1741         static int called = 0;
1742         packet_done();
1743         if (called) {
1744                 return 0;
1745         } else {
1746                 called = 1;
1747                 return auth_input_request_forwarding(s->pw);
1748         }
1749 }
1750
1751 void
1752 session_input_channel_req(int id, void *arg)
1753 {
1754         unsigned int len;
1755         int reply;
1756         int success = 0;
1757         char *rtype;
1758         Session *s;
1759         Channel *c;
1760
1761         rtype = packet_get_string(&len);
1762         reply = packet_get_char();
1763
1764         s = session_by_channel(id);
1765         if (s == NULL)
1766                 fatal("session_input_channel_req: channel %d: no session", id);
1767         c = channel_lookup(id);
1768         if (c == NULL)
1769                 fatal("session_input_channel_req: channel %d: bad channel", id);
1770
1771         debug("session_input_channel_req: session %d channel %d request %s reply %d",
1772             s->self, id, rtype, reply);
1773
1774         /*
1775          * a session is in LARVAL state until a shell
1776          * or programm is executed
1777          */
1778         if (c->type == SSH_CHANNEL_LARVAL) {
1779                 if (strcmp(rtype, "shell") == 0) {
1780                         success = session_shell_req(s);
1781                 } else if (strcmp(rtype, "exec") == 0) {
1782                         success = session_exec_req(s);
1783                 } else if (strcmp(rtype, "pty-req") == 0) {
1784                         success =  session_pty_req(s);
1785                 } else if (strcmp(rtype, "x11-req") == 0) {
1786                         success = session_x11_req(s);
1787                 } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
1788                         success = session_auth_agent_req(s);
1789                 } else if (strcmp(rtype, "subsystem") == 0) {
1790                         success = session_subsystem_req(s);
1791                 }
1792         }
1793         if (strcmp(rtype, "window-change") == 0) {
1794                 success = session_window_change_req(s);
1795         }
1796
1797         if (reply) {
1798                 packet_start(success ?
1799                     SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE);
1800                 packet_put_int(c->remote_id);
1801                 packet_send();
1802         }
1803         xfree(rtype);
1804 }
1805
1806 void
1807 session_set_fds(Session *s, int fdin, int fdout, int fderr)
1808 {
1809         if (!compat20)
1810                 fatal("session_set_fds: called for proto != 2.0");
1811         /*
1812          * now that have a child and a pipe to the child,
1813          * we can activate our channel and register the fd's
1814          */
1815         if (s->chanid == -1)
1816                 fatal("no channel for session %d", s->self);
1817         channel_set_fds(s->chanid,
1818             fdout, fdin, fderr,
1819             fderr == -1 ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
1820             1);
1821 }
1822
1823 void
1824 session_pty_cleanup(Session *s)
1825 {
1826         if (s == NULL || s->ttyfd == -1)
1827                 return;
1828
1829         debug("session_pty_cleanup: session %i release %s", s->self, s->tty);
1830
1831         /* Cancel the cleanup function. */
1832         fatal_remove_cleanup(pty_cleanup_proc, (void *)s);
1833
1834         /* Record that the user has logged out. */
1835         record_logout(s->pid, s->tty);
1836
1837         /* Release the pseudo-tty. */
1838         pty_release(s->tty);
1839
1840         /*
1841          * Close the server side of the socket pairs.  We must do this after
1842          * the pty cleanup, so that another process doesn't get this pty
1843          * while we're still cleaning up.
1844          */
1845         if (close(s->ptymaster) < 0)
1846                 error("close(s->ptymaster): %s", strerror(errno));
1847 }
1848
1849 void
1850 session_exit_message(Session *s, int status)
1851 {
1852         Channel *c;
1853         if (s == NULL)
1854                 fatal("session_close: no session");
1855         c = channel_lookup(s->chanid);
1856         if (c == NULL)
1857                 fatal("session_close: session %d: no channel %d",
1858                     s->self, s->chanid);
1859         debug("session_exit_message: session %d channel %d pid %d",
1860             s->self, s->chanid, s->pid);
1861
1862         if (WIFEXITED(status)) {
1863                 channel_request_start(s->chanid,
1864                     "exit-status", 0);
1865                 packet_put_int(WEXITSTATUS(status));
1866                 packet_send();
1867         } else if (WIFSIGNALED(status)) {
1868                 channel_request_start(s->chanid,
1869                     "exit-signal", 0);
1870                 packet_put_int(WTERMSIG(status));
1871 #ifdef WCOREDUMP
1872                 packet_put_char(WCOREDUMP(status));
1873 #else /* WCOREDUMP */
1874                 packet_put_char(0);
1875 #endif /* WCOREDUMP */
1876                 packet_put_cstring("");
1877                 packet_put_cstring("");
1878                 packet_send();
1879         } else {
1880                 /* Some weird exit cause.  Just exit. */
1881                 packet_disconnect("wait returned status %04x.", status);
1882         }
1883
1884         /* disconnect channel */
1885         debug("session_exit_message: release channel %d", s->chanid);
1886         channel_cancel_cleanup(s->chanid);
1887         /*
1888          * emulate a write failure with 'chan_write_failed', nobody will be
1889          * interested in data we write.
1890          * Note that we must not call 'chan_read_failed', since there could
1891          * be some more data waiting in the pipe.
1892          * djm - This is no longer true as we have allowed one pass through 
1893          * the select loop before killing the connection
1894          */
1895         if (c->ostate != CHAN_OUTPUT_CLOSED)
1896                 chan_write_failed(c);
1897         if (c->istate != CHAN_INPUT_CLOSED)
1898                 chan_read_failed(c);
1899         s->chanid = -1;
1900 }
1901
1902 void
1903 session_free(Session *s)
1904 {
1905         debug("session_free: session %d pid %d", s->self, s->pid);
1906         if (s->term)
1907                 xfree(s->term);
1908         if (s->display)
1909                 xfree(s->display);
1910         if (s->auth_data)
1911                 xfree(s->auth_data);
1912         if (s->auth_proto)
1913                 xfree(s->auth_proto);
1914         s->used = 0;
1915 }
1916
1917 void
1918 session_close(Session *s)
1919 {
1920         session_pty_cleanup(s);
1921         session_free(s);
1922         session_proctitle(s);
1923 }
1924
1925 void
1926 session_close_by_pid(pid_t pid, int status)
1927 {
1928         Session *s = session_by_pid(pid);
1929         if (s == NULL) {
1930                 debug("session_close_by_pid: no session for pid %d", s->pid);
1931                 return;
1932         }
1933         if (s->chanid != -1)
1934                 session_exit_message(s, status);
1935         session_close(s);
1936 }
1937
1938 /*
1939  * this is called when a channel dies before
1940  * the session 'child' itself dies
1941  */
1942 void
1943 session_close_by_channel(int id, void *arg)
1944 {
1945         Session *s = session_by_channel(id);
1946         if (s == NULL) {
1947                 debug("session_close_by_channel: no session for channel %d", id);
1948                 return;
1949         }
1950         /* disconnect channel */
1951         channel_cancel_cleanup(s->chanid);
1952         s->chanid = -1;
1953
1954         debug("session_close_by_channel: channel %d kill %d", id, s->pid);
1955         if (s->pid == 0) {
1956                 /* close session immediately */
1957                 session_close(s);
1958         } else {
1959                 /* notify child, delay session cleanup */
1960                 if (s->pid <= 1) 
1961                         fatal("session_close_by_channel: Unsafe s->pid = %d", s->pid);
1962                 if (kill(s->pid, (s->ttyfd == -1) ? SIGTERM : SIGHUP) < 0)
1963                         error("session_close_by_channel: kill %d: %s",
1964                             s->pid, strerror(errno));
1965         }
1966 }
1967
1968 char *
1969 session_tty_list(void)
1970 {
1971         static char buf[1024];
1972         int i;
1973         buf[0] = '\0';
1974         for(i = 0; i < MAX_SESSIONS; i++) {
1975                 Session *s = &sessions[i];
1976                 if (s->used && s->ttyfd != -1) {
1977                         if (buf[0] != '\0')
1978                                 strlcat(buf, ",", sizeof buf);
1979                         strlcat(buf, strrchr(s->tty, '/') + 1, sizeof buf);
1980                 }
1981         }
1982         if (buf[0] == '\0')
1983                 strlcpy(buf, "notty", sizeof buf);
1984         return buf;
1985 }
1986
1987 void
1988 session_proctitle(Session *s)
1989 {
1990         if (s->pw == NULL)
1991                 error("no user for session %d", s->self);
1992         else
1993                 setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
1994 }
1995
1996 void
1997 do_authenticated2(void)
1998 {
1999 #ifdef HAVE_LOGIN_CAP
2000         struct passwd *pw;
2001 #endif
2002
2003         /*
2004          * Cancel the alarm we set to limit the time taken for
2005          * authentication.
2006          */
2007         alarm(0);
2008         if (startup_pipe != -1) {
2009                 close(startup_pipe);
2010                 startup_pipe = -1;
2011         }
2012 #if defined(HAVE_LOGIN_CAP) && defined(HAVE_PW_CLASS_IN_PASSWD)
2013         pw = auth_get_user();
2014         if ((lc = login_getclass(pw->pw_class)) == NULL) {
2015                 error("unable to get login class");
2016                 return;
2017         }
2018 #endif
2019         server_loop2();
2020         if (xauthfile)
2021                 xauthfile_cleanup_proc(NULL);
2022 }
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