summaryrefslogtreecommitdiff
path: root/session.c
blob: 24bc25c6f1a40d564d46d81280bc268a6e8a6002 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
/*
 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
 *                    All rights reserved
 */
/*
 * SSH2 support by Markus Friedl.
 * Copyright (c) 2000 Markus Friedl. All rights reserved.
 */

#include "includes.h"
RCSID("$OpenBSD: session.c,v 1.4 2000/04/14 10:30:33 markus Exp $");

#include "xmalloc.h"
#include "ssh.h"
#include "pty.h"
#include "packet.h"
#include "buffer.h"
#include "cipher.h"
#include "mpaux.h"
#include "servconf.h"
#include "uidswap.h"
#include "compat.h"
#include "channels.h"
#include "nchan.h"

#include "bufaux.h"
#include "ssh2.h"
#include "auth.h"

/* types */

#define TTYSZ 64
typedef struct Session Session;
struct Session {
	int	used;
	int	self;
	struct	passwd *pw;
	pid_t	pid;
	/* tty */
	char	*term;
	int	ptyfd, ttyfd, ptymaster;
	int	row, col, xpixel, ypixel;
	char	tty[TTYSZ];
	/* X11 */
	char	*display;
	int	screen;
	char	*auth_proto;
	char	*auth_data;
	/* proto 2 */
	int	chanid;
};

/* func */

Session *session_new(void);
void	session_set_fds(Session *s, int fdin, int fdout, int fderr);
void	session_pty_cleanup(Session *s);
void	do_exec_pty(Session *s, const char *command, struct passwd * pw);
void	do_exec_no_pty(Session *s, const char *command, struct passwd * pw);

void
do_child(const char *command, struct passwd * pw, const char *term,
    const char *display, const char *auth_proto,
    const char *auth_data, const char *ttyname);

/* import */
extern ServerOptions options;
extern char *__progname;
extern int log_stderr;
extern int debug_flag;

/* Local Xauthority file. */
static char *xauthfile;

/* data */
#define MAX_SESSIONS 10
Session	sessions[MAX_SESSIONS];

/* Flags set in auth-rsa from authorized_keys flags.  These are set in auth-rsa.c. */
int no_port_forwarding_flag = 0;
int no_agent_forwarding_flag = 0;
int no_x11_forwarding_flag = 0;
int no_pty_flag = 0;

/* RSA authentication "command=" option. */
char *forced_command = NULL;

/* RSA authentication "environment=" options. */
struct envstring *custom_environment = NULL;

/*
 * Remove local Xauthority file.
 */
void
xauthfile_cleanup_proc(void *ignore)
{
	debug("xauthfile_cleanup_proc called");

	if (xauthfile != NULL) {
		char *p;
		unlink(xauthfile);
		p = strrchr(xauthfile, '/');
		if (p != NULL) {
			*p = '\0';
			rmdir(xauthfile);
		}
		xfree(xauthfile);
		xauthfile = NULL;
	}
}

/*
 * Function to perform cleanup if we get aborted abnormally (e.g., due to a
 * dropped connection).
 */
void
pty_cleanup_proc(void *session)
{
	Session *s=session;
	if (s == NULL)
		fatal("pty_cleanup_proc: no session");
	debug("pty_cleanup_proc: %s", s->tty);

	if (s->pid != 0) {
		/* Record that the user has logged out. */
		record_logout(s->pid, s->tty);
	}

	/* Release the pseudo-tty. */
	pty_release(s->tty);
}

/*
 * Prepares for an interactive session.  This is called after the user has
 * been successfully authenticated.  During this message exchange, pseudo
 * terminals are allocated, X11, TCP/IP, and authentication agent forwardings
 * are requested, etc.
 */
void
do_authenticated(struct passwd * pw)
{
	Session *s;
	int type;
	int compression_level = 0, enable_compression_after_reply = 0;
	int have_pty = 0;
	char *command;
	int n_bytes;
	int plen;
	unsigned int proto_len, data_len, dlen;

	/*
	 * Cancel the alarm we set to limit the time taken for
	 * authentication.
	 */
	alarm(0);

	/*
	 * Inform the channel mechanism that we are the server side and that
	 * the client may request to connect to any port at all. (The user
	 * could do it anyway, and we wouldn\'t know what is permitted except
	 * by the client telling us, so we can equally well trust the client
	 * not to request anything bogus.)
	 */
	if (!no_port_forwarding_flag)
		channel_permit_all_opens();

	s = session_new();

	/*
	 * We stay in this loop until the client requests to execute a shell
	 * or a command.
	 */
	for (;;) {
		int success = 0;

		/* Get a packet from the client. */
		type = packet_read(&plen);

		/* Process the packet. */
		switch (type) {
		case SSH_CMSG_REQUEST_COMPRESSION:
			packet_integrity_check(plen, 4, type);
			compression_level = packet_get_int();
			if (compression_level < 1 || compression_level > 9) {
				packet_send_debug("Received illegal compression level %d.",
				     compression_level);
				break;
			}
			/* Enable compression after we have responded with SUCCESS. */
			enable_compression_after_reply = 1;
			success = 1;
			break;

		case SSH_CMSG_REQUEST_PTY:
			if (no_pty_flag) {
				debug("Allocating a pty not permitted for this authentication.");
				break;
			}
			if (have_pty)
				packet_disconnect("Protocol error: you already have a pty.");

			debug("Allocating pty.");

			/* Allocate a pty and open it. */
			if (!pty_allocate(&s->ptyfd, &s->ttyfd, s->tty,
			    sizeof(s->tty))) {
				error("Failed to allocate pty.");
				break;
			}
			fatal_add_cleanup(pty_cleanup_proc, (void *)s);
			pty_setowner(pw, s->tty);

			/* Get TERM from the packet.  Note that the value may be of arbitrary length. */
			s->term = packet_get_string(&dlen);
			packet_integrity_check(dlen, strlen(s->term), type);
			/* packet_integrity_check(plen, 4 + dlen + 4*4 + n_bytes, type); */
			/* Remaining bytes */
			n_bytes = plen - (4 + dlen + 4 * 4);

			if (strcmp(s->term, "") == 0) {
				xfree(s->term);
				s->term = NULL;
			}
			/* Get window size from the packet. */
			s->row = packet_get_int();
			s->col = packet_get_int();
			s->xpixel = packet_get_int();
			s->ypixel = packet_get_int();
			pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);

			/* Get tty modes from the packet. */
			tty_parse_modes(s->ttyfd, &n_bytes);
			packet_integrity_check(plen, 4 + dlen + 4 * 4 + n_bytes, type);

			/* Indicate that we now have a pty. */
			success = 1;
			have_pty = 1;
			break;

		case SSH_CMSG_X11_REQUEST_FORWARDING:
			if (!options.x11_forwarding) {
				packet_send_debug("X11 forwarding disabled in server configuration file.");
				break;
			}
#ifdef XAUTH_PATH
			if (no_x11_forwarding_flag) {
				packet_send_debug("X11 forwarding not permitted for this authentication.");
				break;
			}
			debug("Received request for X11 forwarding with auth spoofing.");
			if (s->display != NULL)
				packet_disconnect("Protocol error: X11 display already set.");

			s->auth_proto = packet_get_string(&proto_len);
			s->auth_data = packet_get_string(&data_len);
			packet_integrity_check(plen, 4 + proto_len + 4 + data_len + 4, type);

			if (packet_get_protocol_flags() & SSH_PROTOFLAG_SCREEN_NUMBER)
				s->screen = packet_get_int();
			else
				s->screen = 0;
			s->display = x11_create_display_inet(s->screen, options.x11_display_offset);

			if (s->display == NULL)
				break;

			/* Setup to always have a local .Xauthority. */
			xauthfile = xmalloc(MAXPATHLEN);
			strlcpy(xauthfile, "/tmp/ssh-XXXXXXXX", MAXPATHLEN);
			temporarily_use_uid(pw->pw_uid);
			if (mkdtemp(xauthfile) == NULL) {
				restore_uid();
				error("private X11 dir: mkdtemp %s failed: %s",
				    xauthfile, strerror(errno));
				xfree(xauthfile);
				xauthfile = NULL;
				break;
			}
			strlcat(xauthfile, "/cookies", MAXPATHLEN);
			open(xauthfile, O_RDWR|O_CREAT|O_EXCL, 0600);
			restore_uid();
			fatal_add_cleanup(xauthfile_cleanup_proc, NULL);
			success = 1;
			break;
#else /* XAUTH_PATH */
			packet_send_debug("No xauth program; cannot forward with spoofing.");
			break;
#endif /* XAUTH_PATH */

		case SSH_CMSG_AGENT_REQUEST_FORWARDING:
			if (no_agent_forwarding_flag || compat13) {
				debug("Authentication agent forwarding not permitted for this authentication.");
				break;
			}
			debug("Received authentication agent forwarding request.");
			auth_input_request_forwarding(pw);
			success = 1;
			break;

		case SSH_CMSG_PORT_FORWARD_REQUEST:
			if (no_port_forwarding_flag) {
				debug("Port forwarding not permitted for this authentication.");
				break;
			}
			debug("Received TCP/IP port forwarding request.");
			channel_input_port_forward_request(pw->pw_uid == 0);
			success = 1;
			break;

		case SSH_CMSG_MAX_PACKET_SIZE:
			if (packet_set_maxsize(packet_get_int()) > 0)
				success = 1;
			break;

		case SSH_CMSG_EXEC_SHELL:
		case SSH_CMSG_EXEC_CMD:
			/* Set interactive/non-interactive mode. */
			packet_set_interactive(have_pty || s->display != NULL,
			    options.keepalives);

			if (type == SSH_CMSG_EXEC_CMD) {
				command = packet_get_string(&dlen);
				debug("Exec command '%.500s'", command);
				packet_integrity_check(plen, 4 + dlen, type);
			} else {
				command = NULL;
				packet_integrity_check(plen, 0, type);
			}
			if (forced_command != NULL) {
				command = forced_command;
				debug("Forced command '%.500s'", forced_command);
			}
			if (have_pty)
				do_exec_pty(s, command, pw);
			else
				do_exec_no_pty(s, command, pw);

			if (command != NULL)
				xfree(command);
			/* Cleanup user's local Xauthority file. */
			if (xauthfile)
				xauthfile_cleanup_proc(NULL);
			return;

		default:
			/*
			 * Any unknown messages in this phase are ignored,
			 * and a failure message is returned.
			 */
			log("Unknown packet type received after authentication: %d", type);
		}
		packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE);
		packet_send();
		packet_write_wait();

		/* Enable compression now that we have replied if appropriate. */
		if (enable_compression_after_reply) {
			enable_compression_after_reply = 0;
			packet_start_compression(compression_level);
		}
	}
}

/*
 * This is called to fork and execute a command when we have no tty.  This
 * will call do_child from the child, and server_loop from the parent after
 * setting up file descriptors and such.
 */
void
do_exec_no_pty(Session *s, const char *command, struct passwd * pw)
{
	int pid;

#ifdef USE_PIPES
	int pin[2], pout[2], perr[2];
	/* Allocate pipes for communicating with the program. */
	if (pipe(pin) < 0 || pipe(pout) < 0 || pipe(perr) < 0)
		packet_disconnect("Could not create pipes: %.100s",
				  strerror(errno));
#else /* USE_PIPES */
	int inout[2], err[2];
	/* Uses socket pairs to communicate with the program. */
	if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0 ||
	    socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0)
		packet_disconnect("Could not create socket pairs: %.100s",
				  strerror(errno));
#endif /* USE_PIPES */
	if (s == NULL)
		fatal("do_exec_no_pty: no session");

	setproctitle("%s@notty", pw->pw_name);

#ifdef USE_PAM
			do_pam_setcred();
#endif /* USE_PAM */

	/* Fork the child. */
	if ((pid = fork()) == 0) {
		/* Child.  Reinitialize the log since the pid has changed. */
		log_init(__progname, options.log_level, options.log_facility, log_stderr);

		/*
		 * Create a new session and process group since the 4.4BSD
		 * setlogin() affects the entire process group.
		 */
		if (setsid() < 0)
			error("setsid failed: %.100s", strerror(errno));

#ifdef USE_PIPES
		/*
		 * Redirect stdin.  We close the parent side of the socket
		 * pair, and make the child side the standard input.
		 */
		close(pin[1]);
		if (dup2(pin[0], 0) < 0)
			perror("dup2 stdin");
		close(pin[0]);

		/* Redirect stdout. */
		close(pout[0]);
		if (dup2(pout[1], 1) < 0)
			perror("dup2 stdout");
		close(pout[1]);

		/* Redirect stderr. */
		close(perr[0]);
		if (dup2(perr[1], 2) < 0)
			perror("dup2 stderr");
		close(perr[1]);
#else /* USE_PIPES */
		/*
		 * Redirect stdin, stdout, and stderr.  Stdin and stdout will
		 * use the same socket, as some programs (particularly rdist)
		 * seem to depend on it.
		 */
		close(inout[1]);
		close(err[1]);
		if (dup2(inout[0], 0) < 0)	/* stdin */
			perror("dup2 stdin");
		if (dup2(inout[0], 1) < 0)	/* stdout.  Note: same socket as stdin. */
			perror("dup2 stdout");
		if (dup2(err[0], 2) < 0)	/* stderr */
			perror("dup2 stderr");
#endif /* USE_PIPES */

		/* Do processing for the child (exec command etc). */
		do_child(command, pw, NULL, s->display, s->auth_proto, s->auth_data, NULL);
		/* NOTREACHED */
	}
	if (pid < 0)
		packet_disconnect("fork failed: %.100s", strerror(errno));
	s->pid = pid;
#ifdef USE_PIPES
	/* We are the parent.  Close the child sides of the pipes. */
	close(pin[0]);
	close(pout[1]);
	close(perr[1]);

	if (compat20) {
		session_set_fds(s, pin[1], pout[0], perr[0]);
	} else {
		/* Enter the interactive session. */
		server_loop(pid, pin[1], pout[0], perr[0]);
		/* server_loop has closed pin[1], pout[1], and perr[1]. */
	}
#else /* USE_PIPES */
	/* We are the parent.  Close the child sides of the socket pairs. */
	close(inout[0]);
	close(err[0]);

	/*
	 * Enter the interactive session.  Note: server_loop must be able to
	 * handle the case that fdin and fdout are the same.
	 */
	if (compat20) {
		session_set_fds(s, inout[1], inout[1], err[1]);
	} else {
		server_loop(pid, inout[1], inout[1], err[1]);
		/* server_loop has closed inout[1] and err[1]. */
	}
#endif /* USE_PIPES */
}

/*
 * This is called to fork and execute a command when we have a tty.  This
 * will call do_child from the child, and server_loop from the parent after
 * setting up file descriptors, controlling tty, updating wtmp, utmp,
 * lastlog, and other such operations.
 */
void
do_exec_pty(Session *s, const char *command, struct passwd * pw)
{
	FILE *f;
	char buf[100], *time_string;
	char line[256];
	const char *hostname;
	int fdout, ptyfd, ttyfd, ptymaster;
	int quiet_login;
	pid_t pid;
	socklen_t fromlen;
	struct sockaddr_storage from;
	struct stat st;
	time_t last_login_time;

	if (s == NULL)
		fatal("do_exec_pty: no session");
	ptyfd = s->ptyfd;
	ttyfd = s->ttyfd;

	/* Get remote host name. */
	hostname = get_canonical_hostname();

	/*
	 * Get the time when the user last logged in.  Buf will be set to
	 * contain the hostname the last login was from.
	 */
	if (!options.use_login) {
		last_login_time = get_last_login_time(pw->pw_uid, pw->pw_name,
						      buf, sizeof(buf));
	}
	setproctitle("%s@%s", pw->pw_name, strrchr(s->tty, '/') + 1);

#ifdef USE_PAM
			do_pam_session(pw->pw_name, s->tty);
			do_pam_setcred();
#endif /* USE_PAM */

	/* Fork the child. */
	if ((pid = fork()) == 0) {
		pid = getpid();

		/* Child.  Reinitialize the log because the pid has
		   changed. */
		log_init(__progname, options.log_level, options.log_facility, log_stderr);

		/* Close the master side of the pseudo tty. */
		close(ptyfd);

		/* Make the pseudo tty our controlling tty. */
		pty_make_controlling_tty(&ttyfd, s->tty);

		/* Redirect stdin from the pseudo tty. */
		if (dup2(ttyfd, fileno(stdin)) < 0)
			error("dup2 stdin failed: %.100s", strerror(errno));

		/* Redirect stdout to the pseudo tty. */
		if (dup2(ttyfd, fileno(stdout)) < 0)
			error("dup2 stdin failed: %.100s", strerror(errno));

		/* Redirect stderr to the pseudo tty. */
		if (dup2(ttyfd, fileno(stderr)) < 0)
			error("dup2 stdin failed: %.100s", strerror(errno));

		/* Close the extra descriptor for the pseudo tty. */
		close(ttyfd);

///XXXX ? move to do_child() ??
		/*
		 * Get IP address of client.  This is needed because we want
		 * to record where the user logged in from.  If the
		 * connection is not a socket, let the ip address be 0.0.0.0.
		 */
		memset(&from, 0, sizeof(from));
		if (packet_connection_is_on_socket()) {
			fromlen = sizeof(from);
			if (getpeername(packet_get_connection_in(),
			     (struct sockaddr *) & from, &fromlen) < 0) {
				debug("getpeername: %.100s", strerror(errno));
				fatal_cleanup();
			}
		}
		/* Record that there was a login on that terminal. */
		record_login(pid, s->tty, pw->pw_name, pw->pw_uid, hostname,
			     (struct sockaddr *)&from);

		/* Check if .hushlogin exists. */
		snprintf(line, sizeof line, "%.200s/.hushlogin", pw->pw_dir);
		quiet_login = stat(line, &st) >= 0;

#ifdef USE_PAM
		if (!quiet_login)
			print_pam_messages();
#endif /* USE_PAM */

		/*
		 * If the user has logged in before, display the time of last
		 * login. However, don't display anything extra if a command
		 * has been specified (so that ssh can be used to execute
		 * commands on a remote machine without users knowing they
		 * are going to another machine). Login(1) will do this for
		 * us as well, so check if login(1) is used
		 */
		if (command == NULL && last_login_time != 0 && !quiet_login &&
		    !options.use_login) {
			/* Convert the date to a string. */
			time_string = ctime(&last_login_time);
			/* Remove the trailing newline. */
			if (strchr(time_string, '\n'))
				*strchr(time_string, '\n') = 0;
			/* Display the last login time.  Host if displayed
			   if known. */
			if (strcmp(buf, "") == 0)
				printf("Last login: %s\r\n", time_string);
			else
				printf("Last login: %s from %s\r\n", time_string, buf);
		}
		/*
		 * Print /etc/motd unless a command was specified or printing
		 * it was disabled in server options or login(1) will be
		 * used.  Note that some machines appear to print it in
		 * /etc/profile or similar.
		 */
		if (command == NULL && options.print_motd && !quiet_login &&
		    !options.use_login) {
			/* Print /etc/motd if it exists. */
			f = fopen("/etc/motd", "r");
			if (f) {
				while (fgets(line, sizeof(line), f))
					fputs(line, stdout);
				fclose(f);
			}
		}
		/* Do common processing for the child, such as execing the command. */
		do_child(command, pw, s->term, s->display, s->auth_proto, s->auth_data, s->tty);
		/* NOTREACHED */
	}
	if (pid < 0)
		packet_disconnect("fork failed: %.100s", strerror(errno));
	s->pid = pid;

	/* Parent.  Close the slave side of the pseudo tty. */
	close(ttyfd);

	/*
	 * Create another descriptor of the pty master side for use as the
	 * standard input.  We could use the original descriptor, but this
	 * simplifies code in server_loop.  The descriptor is bidirectional.
	 */
	fdout = dup(ptyfd);
	if (fdout < 0)
		packet_disconnect("dup #1 failed: %.100s", strerror(errno));

	/* we keep a reference to the pty master */
	ptymaster = dup(ptyfd);
	if (ptymaster < 0)
		packet_disconnect("dup #2 failed: %.100s", strerror(errno));
	s->ptymaster = ptymaster;

	/* Enter interactive session. */
	if (compat20) {
		session_set_fds(s, ptyfd, fdout, -1);
	} else {
		server_loop(pid, ptyfd, fdout, -1);
		/* server_loop _has_ closed ptyfd and fdout. */
		session_pty_cleanup(s);
	}
}

/*
 * Sets the value of the given variable in the environment.  If the variable
 * already exists, its value is overriden.
 */
void
child_set_env(char ***envp, unsigned int *envsizep, const char *name,
	      const char *value)
{
	unsigned int i, namelen;
	char **env;

	/*
	 * Find the slot where the value should be stored.  If the variable
	 * already exists, we reuse the slot; otherwise we append a new slot
	 * at the end of the array, expanding if necessary.
	 */
	env = *envp;
	namelen = strlen(name);
	for (i = 0; env[i]; i++)
		if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
			break;
	if (env[i]) {
		/* Reuse the slot. */
		xfree(env[i]);
	} else {
		/* New variable.  Expand if necessary. */
		if (i >= (*envsizep) - 1) {
			(*envsizep) += 50;
			env = (*envp) = xrealloc(env, (*envsizep) * sizeof(char *));
		}
		/* Need to set the NULL pointer at end of array beyond the new slot. */
		env[i + 1] = NULL;
	}

	/* Allocate space and format the variable in the appropriate slot. */
	env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
	snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
}

/*
 * Reads environment variables from the given file and adds/overrides them
 * into the environment.  If the file does not exist, this does nothing.
 * Otherwise, it must consist of empty lines, comments (line starts with '#')
 * and assignments of the form name=value.  No other forms are allowed.
 */
void
read_environment_file(char ***env, unsigned int *envsize,
		      const char *filename)
{
	FILE *f;
	char buf[4096];
	char *cp, *value;

	f = fopen(filename, "r");
	if (!f)
		return;

	while (fgets(buf, sizeof(buf), f)) {
		for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
			;
		if (!*cp || *cp == '#' || *cp == '\n')
			continue;
		if (strchr(cp, '\n'))
			*strchr(cp, '\n') = '\0';
		value = strchr(cp, '=');
		if (value == NULL) {
			fprintf(stderr, "Bad line in %.100s: %.200s\n", filename, buf);
			continue;
		}
		/* Replace the equals sign by nul, and advance value to the value string. */
		*value = '\0';
		value++;
		child_set_env(env, envsize, cp, value);
	}
	fclose(f);
}

#ifdef USE_PAM
/*
 * Sets any environment variables which have been specified by PAM
 */
void do_pam_environment(char ***env, int *envsize)
{
	char *equals, var_name[512], var_val[512];
	char **pam_env;
	int i;

	if ((pam_env = fetch_pam_environment()) == NULL)
		return;
	
	for(i = 0; pam_env[i] != NULL; i++) {
		if ((equals = strstr(pam_env[i], "=")) == NULL)
			continue;
			
		if (strlen(pam_env[i]) < (sizeof(var_name) - 1)) {
			memset(var_name, '\0', sizeof(var_name));
			memset(var_val, '\0', sizeof(var_val));

			strncpy(var_name, pam_env[i], equals - pam_env[i]);
			strcpy(var_val, equals + 1);

			debug("PAM environment: %s=%s", var_name, var_val);

			child_set_env(env, envsize, var_name, var_val);
		}
	}
}
#endif /* USE_PAM */

/*
 * Performs common processing for the child, such as setting up the
 * environment, closing extra file descriptors, setting the user and group
 * ids, and executing the command or shell.
 */
void
do_child(const char *command, struct passwd * pw, const char *term,
	 const char *display, const char *auth_proto,
	 const char *auth_data, const char *ttyname)
{
	const char *shell, *cp = NULL;
	char buf[256];
	FILE *f;
	unsigned int envsize, i;
	char **env;
	extern char **environ;
	struct stat st;
	char *argv[10];

#ifndef USE_PAM /* pam_nologin handles this */
	f = fopen("/etc/nologin", "r");
	if (f) {
		/* /etc/nologin exists.  Print its contents and exit. */
		while (fgets(buf, sizeof(buf), f))
			fputs(buf, stderr);
		fclose(f);
		if (pw->pw_uid != 0)
			exit(254);
	}
#endif /* USE_PAM */

	/* Set login name in the kernel. */
	if (setlogin(pw->pw_name) < 0)
		error("setlogin failed: %s", strerror(errno));

	/* Set uid, gid, and groups. */
	/* Login(1) does this as well, and it needs uid 0 for the "-h"
	   switch, so we let login(1) to this for us. */
	if (!options.use_login) {
		if (getuid() == 0 || geteuid() == 0) {
			if (setgid(pw->pw_gid) < 0) {
				perror("setgid");
				exit(1);
			}
			/* Initialize the group list. */
			if (initgroups(pw->pw_name, pw->pw_gid) < 0) {
				perror("initgroups");
				exit(1);
			}
			endgrent();

			/* Permanently switch to the desired uid. */
			permanently_set_uid(pw->pw_uid);
		}
		if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
			fatal("Failed to set uids to %d.", (int) pw->pw_uid);
	}
	/*
	 * Get the shell from the password data.  An empty shell field is
	 * legal, and means /bin/sh.
	 */
	shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;

#ifdef AFS
	/* Try to get AFS tokens for the local cell. */
	if (k_hasafs()) {
		char cell[64];

		if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
			krb_afslog(cell, 0);

		krb_afslog(0, 0);
	}
#endif /* AFS */

	/* Initialize the environment. */
	envsize = 100;
	env = xmalloc(envsize * sizeof(char *));
	env[0] = NULL;

	if (!options.use_login) {
		/* Set basic environment. */
		child_set_env(&env, &envsize, "USER", pw->pw_name);
		child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
		child_set_env(&env, &envsize, "HOME", pw->pw_dir);
		child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);

		snprintf(buf, sizeof buf, "%.200s/%.50s",
			 _PATH_MAILDIR, pw->pw_name);
		child_set_env(&env, &envsize, "MAIL", buf);

		/* Normal systems set SHELL by default. */
		child_set_env(&env, &envsize, "SHELL", shell);
	}
	if (getenv("TZ"))
		child_set_env(&env, &envsize, "TZ", getenv("TZ"));

	/* Set custom environment options from RSA authentication. */
	while (custom_environment) {
		struct envstring *ce = custom_environment;
		char *s = ce->s;
		int i;
		for (i = 0; s[i] != '=' && s[i]; i++);
		if (s[i] == '=') {
			s[i] = 0;
			child_set_env(&env, &envsize, s, s + i + 1);
		}
		custom_environment = ce->next;
		xfree(ce->s);
		xfree(ce);
	}

	snprintf(buf, sizeof buf, "%.50s %d %d",
		 get_remote_ipaddr(), get_remote_port(), get_local_port());
	child_set_env(&env, &envsize, "SSH_CLIENT", buf);

	if (ttyname)
		child_set_env(&env, &envsize, "SSH_TTY", ttyname);
	if (term)
		child_set_env(&env, &envsize, "TERM", term);
	if (display)
		child_set_env(&env, &envsize, "DISPLAY", display);

#ifdef _AIX
	{
           char *authstate,*krb5cc;

	   if ((authstate = getenv("AUTHSTATE")) != NULL)
		 child_set_env(&env,&envsize,"AUTHSTATE",authstate);

	   if ((krb5cc = getenv("KRB5CCNAME")) != NULL)
		 child_set_env(&env,&envsize,"KRB5CCNAME",krb5cc);
	}
#endif

#ifdef KRB4
	{
		extern char *ticket;

		if (ticket)
			child_set_env(&env, &envsize, "KRBTKFILE", ticket);
	}
#endif /* KRB4 */

#ifdef USE_PAM
	/* Pull in any environment variables that may have been set by PAM. */
	do_pam_environment(&env, &envsize);
#endif /* USE_PAM */

	read_environment_file(&env,&envsize,"/etc/environment");

	if (xauthfile)
		child_set_env(&env, &envsize, "XAUTHORITY", xauthfile);
	if (auth_get_socket_name() != NULL)
		child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
			      auth_get_socket_name());

	/* read $HOME/.ssh/environment. */
	if (!options.use_login) {
		snprintf(buf, sizeof buf, "%.200s/.ssh/environment", pw->pw_dir);
		read_environment_file(&env, &envsize, buf);
	}
	if (debug_flag) {
		/* dump the environment */
		fprintf(stderr, "Environment:\n");
		for (i = 0; env[i]; i++)
			fprintf(stderr, "  %.200s\n", env[i]);
	}
	/*
	 * Close the connection descriptors; note that this is the child, and
	 * the server will still have the socket open, and it is important
	 * that we do not shutdown it.  Note that the descriptors cannot be
	 * closed before building the environment, as we call
	 * get_remote_ipaddr there.
	 */
	if (packet_get_connection_in() == packet_get_connection_out())
		close(packet_get_connection_in());
	else {
		close(packet_get_connection_in());
		close(packet_get_connection_out());
	}
	/*
	 * Close all descriptors related to channels.  They will still remain
	 * open in the parent.
	 */
	/* XXX better use close-on-exec? -markus */
	channel_close_all();

	/*
	 * Close any extra file descriptors.  Note that there may still be
	 * descriptors left by system functions.  They will be closed later.
	 */
	endpwent();

	/*
	 * Close any extra open file descriptors so that we don\'t have them
	 * hanging around in clients.  Note that we want to do this after
	 * initgroups, because at least on Solaris 2.3 it leaves file
	 * descriptors open.
	 */
	for (i = 3; i < 64; i++)
		close(i);

	/* Change current directory to the user\'s home directory. */
	if (chdir(pw->pw_dir) < 0)
		fprintf(stderr, "Could not chdir to home directory %s: %s\n",
			pw->pw_dir, strerror(errno));

	/*
	 * Must take new environment into use so that .ssh/rc, /etc/sshrc and
	 * xauth are run in the proper environment.
	 */
	environ = env;

	/*
	 * Run $HOME/.ssh/rc, /etc/sshrc, or xauth (whichever is found first
	 * in this order).
	 */
	if (!options.use_login) {
		if (stat(SSH_USER_RC, &st) >= 0) {
			if (debug_flag)
				fprintf(stderr, "Running /bin/sh %s\n", SSH_USER_RC);

			f = popen("/bin/sh " SSH_USER_RC, "w");
			if (f) {
				if (auth_proto != NULL && auth_data != NULL)
					fprintf(f, "%s %s\n", auth_proto, auth_data);
				pclose(f);
			} else
				fprintf(stderr, "Could not run %s\n", SSH_USER_RC);
		} else if (stat(SSH_SYSTEM_RC, &st) >= 0) {
			if (debug_flag)
				fprintf(stderr, "Running /bin/sh %s\n", SSH_SYSTEM_RC);

			f = popen("/bin/sh " SSH_SYSTEM_RC, "w");
			if (f) {
				if (auth_proto != NULL && auth_data != NULL)
					fprintf(f, "%s %s\n", auth_proto, auth_data);
				pclose(f);
			} else
				fprintf(stderr, "Could not run %s\n", SSH_SYSTEM_RC);
		}
#ifdef XAUTH_PATH
		else {
			/* Add authority data to .Xauthority if appropriate. */
			if (auth_proto != NULL && auth_data != NULL) {
				if (debug_flag)
					fprintf(stderr, "Running %.100s add %.100s %.100s %.100s\n",
						XAUTH_PATH, display, auth_proto, auth_data);

				f = popen(XAUTH_PATH " -q -", "w");
				if (f) {
					fprintf(f, "add %s %s %s\n", display, auth_proto, auth_data);
					pclose(f);
				} else
					fprintf(stderr, "Could not run %s -q -\n", XAUTH_PATH);
			}
		}
#endif /* XAUTH_PATH */

		/* Get the last component of the shell name. */
		cp = strrchr(shell, '/');
		if (cp)
			cp++;
		else
			cp = shell;
	}
	/*
	 * If we have no command, execute the shell.  In this case, the shell
	 * name to be passed in argv[0] is preceded by '-' to indicate that
	 * this is a login shell.
	 */
	if (!command) {
		if (!options.use_login) {
			char buf[256];

			/*
			 * Check for mail if we have a tty and it was enabled
			 * in server options.
			 */
			if (ttyname && options.check_mail) {
				char *mailbox;
				struct stat mailstat;
				mailbox = getenv("MAIL");
				if (mailbox != NULL) {
					if (stat(mailbox, &mailstat) != 0 || mailstat.st_size == 0)
						printf("No mail.\n");
					else if (mailstat.st_mtime < mailstat.st_atime)
						printf("You have mail.\n");
					else
						printf("You have new mail.\n");
				}
			}
			/* Start the shell.  Set initial character to '-'. */
			buf[0] = '-';
			strncpy(buf + 1, cp, sizeof(buf) - 1);
			buf[sizeof(buf) - 1] = 0;

			/* Execute the shell. */
			argv[0] = buf;
			argv[1] = NULL;
			execve(shell, argv, env);

			/* Executing the shell failed. */
			perror(shell);
			exit(1);

		} else {
			/* Launch login(1). */

			execl("/usr/bin/login", "login", "-h", get_remote_ipaddr(),
			      "-p", "-f", "--", pw->pw_name, NULL);

			/* Login couldn't be executed, die. */

			perror("login");
			exit(1);
		}
	}
	/*
	 * Execute the command using the user's shell.  This uses the -c
	 * option to execute the command.
	 */
	argv[0] = (char *) cp;
	argv[1] = "-c";
	argv[2] = (char *) command;
	argv[3] = NULL;
	execve(shell, argv, env);
	perror(shell);
	exit(1);
}

Session *
session_new(void)
{
	int i;
	static int did_init = 0;
	if (!did_init) {
		debug("session_new: init");
		for(i = 0; i < MAX_SESSIONS; i++) {
			sessions[i].used = 0;
			sessions[i].self = i;
		}
		did_init = 1;
	}
	for(i = 0; i < MAX_SESSIONS; i++) {
		Session *s = &sessions[i];
		if (! s->used) {
			s->pid = 0;
			s->chanid = -1;
			s->ptyfd = -1;
			s->ttyfd = -1;
			s->term = NULL;
			s->pw = NULL;
			s->display = NULL;
			s->screen = 0;
			s->auth_data = NULL;
			s->auth_proto = NULL;
			s->used = 1;
			debug("session_new: session %d", i);
			return s;
		}
	}
	return NULL;
}

void
session_dump(void)
{
	int i;
	for(i = 0; i < MAX_SESSIONS; i++) {
		Session *s = &sessions[i];
		debug("dump: used %d session %d %p channel %d pid %d",
		    s->used,
		    s->self,
		    s,
		    s->chanid,
		    s->pid);
	}
}

int
session_open(int chanid)
{
	Session *s = session_new();
	debug("session_open: channel %d", chanid);
	if (s == NULL) {
		error("no more sessions");
		return 0;
	}
	debug("session_open: session %d: link with channel %d", s->self, chanid);
	s->chanid = chanid;
	s->pw = auth_get_user();
	if (s->pw == NULL)
		fatal("no user for session %i channel %d",
		    s->self, s->chanid);
	return 1;
}

Session *
session_by_channel(int id)
{
	int i;
	for(i = 0; i < MAX_SESSIONS; i++) {
		Session *s = &sessions[i];
		if (s->used && s->chanid == id) {
			debug("session_by_channel: session %d channel %d", i, id);
			return s;
		}
	}
	debug("session_by_channel: unknown channel %d", id);
	session_dump();
	return NULL;
}

Session *
session_by_pid(pid_t pid)
{
	int i;
	debug("session_by_pid: pid %d", pid);
	for(i = 0; i < MAX_SESSIONS; i++) {
		Session *s = &sessions[i];
		if (s->used && s->pid == pid)
			return s;
	}
	error("session_by_pid: unknown pid %d", pid);
	session_dump();
	return NULL;
}

int
session_window_change_req(Session *s)
{
	s->col = packet_get_int();
	s->row = packet_get_int();
	s->xpixel = packet_get_int();
	s->ypixel = packet_get_int();
	packet_done();
	pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
	return 1;
}

int
session_pty_req(Session *s)
{
	unsigned int len;
	char *term_modes;	/* encoded terminal modes */

	if (s->ttyfd != -1)
		return 0;
	s->term = packet_get_string(&len);
	s->col = packet_get_int();
	s->row = packet_get_int();
	s->xpixel = packet_get_int();
	s->ypixel = packet_get_int();
	term_modes = packet_get_string(&len);
	packet_done();

	if (strcmp(s->term, "") == 0) {
		xfree(s->term);
		s->term = NULL;
	}
	/* Allocate a pty and open it. */
	if (!pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty))) {
		xfree(s->term);
		s->term = NULL;
		s->ptyfd = -1;
		s->ttyfd = -1;
		error("session_pty_req: session %d alloc failed", s->self);
		xfree(term_modes);
		return 0;
	}
	debug("session_pty_req: session %d alloc %s", s->self, s->tty);
	/*
	 * Add a cleanup function to clear the utmp entry and record logout
	 * time in case we call fatal() (e.g., the connection gets closed).
	 */
	fatal_add_cleanup(pty_cleanup_proc, (void *)s);
	pty_setowner(s->pw, s->tty);
	/* Get window size from the packet. */
	pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);

	/* XXX parse and set terminal modes */
	xfree(term_modes);
	return 1;
}

void
session_input_channel_req(int id, void *arg)
{
	unsigned int len;
	int reply;
	int success = 0;
	char *rtype;
	Session *s;
	Channel *c;

	rtype = packet_get_string(&len);
	reply = packet_get_char();

	s = session_by_channel(id);
	if (s == NULL)
		fatal("session_input_channel_req: channel %d: no session", id);
	c = channel_lookup(id);
	if (c == NULL)
		fatal("session_input_channel_req: channel %d: bad channel", id);

	debug("session_input_channel_req: session %d channel %d request %s reply %d",
	    s->self, id, rtype, reply);

	/*
	 * a session is in LARVAL state until a shell
	 * or programm is executed
	 */
	if (c->type == SSH_CHANNEL_LARVAL) {
		if (strcmp(rtype, "shell") == 0) {
			if (s->ttyfd == -1)
				do_exec_no_pty(s, NULL, s->pw);
			else
				do_exec_pty(s, NULL, s->pw);
			success = 1;
		} else if (strcmp(rtype, "exec") == 0) {
			char *command = packet_get_string(&len);
			packet_done();
			if (s->ttyfd == -1)
				do_exec_no_pty(s, command, s->pw);
			else
				do_exec_pty(s, command, s->pw);
			xfree(command);
			success = 1;
		} else if (strcmp(rtype, "pty-req") == 0) {
			success =  session_pty_req(s);
		}
	}
	if (strcmp(rtype, "window-change") == 0) {
		success = session_window_change_req(s);
	}

	if (reply) {
		packet_start(success ?
		    SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE);
		packet_put_int(c->remote_id);
		packet_send();
	}
	xfree(rtype);
}

void
session_set_fds(Session *s, int fdin, int fdout, int fderr)
{
	if (!compat20)
		fatal("session_set_fds: called for proto != 2.0");
	/*
	 * now that have a child and a pipe to the child,
	 * we can activate our channel and register the fd's
	 */
	if (s->chanid == -1)
		fatal("no channel for session %d", s->self);
	channel_set_fds(s->chanid,
	    fdout, fdin, fderr,
	    fderr == -1 ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ);
}

void
session_pty_cleanup(Session *s)
{
	if (s == NULL || s->ttyfd == -1)
		return;

	debug("session_pty_cleanup: session %i release %s", s->self, s->tty);

	/* Cancel the cleanup function. */
	fatal_remove_cleanup(pty_cleanup_proc, (void *)s);

	/* Record that the user has logged out. */
	record_logout(s->pid, s->tty);

	/* Release the pseudo-tty. */
	pty_release(s->tty);

	/*
	 * Close the server side of the socket pairs.  We must do this after
	 * the pty cleanup, so that another process doesn't get this pty
	 * while we're still cleaning up.
	 */
	if (close(s->ptymaster) < 0)
		error("close(s->ptymaster): %s", strerror(errno));
}

void
session_exit_message(Session *s, int status)
{
	Channel *c;
	if (s == NULL)
		fatal("session_close: no session");
	c = channel_lookup(s->chanid);
	if (c == NULL)
		fatal("session_close: session %d: no channel %d",
		    s->self, s->chanid);
	debug("session_exit_message: session %d channel %d pid %d",
	    s->self, s->chanid, s->pid);

	if (WIFEXITED(status)) {
		channel_request_start(s->chanid,
		    "exit-status", 0);
		packet_put_int(WEXITSTATUS(status));
		packet_send();
	} else if (WIFSIGNALED(status)) {
		channel_request_start(s->chanid,
		    "exit-signal", 0);
		packet_put_int(WTERMSIG(status));
		packet_put_char(WCOREDUMP(status));
		packet_put_cstring("");
		packet_put_cstring("");
		packet_send();
	} else {
		/* Some weird exit cause.  Just exit. */
		packet_disconnect("wait returned status %04x.", status);
	}

	/* disconnect channel */
	debug("session_exit_message: release channel %d", s->chanid);
	channel_cancel_cleanup(s->chanid);
	if (c->istate == CHAN_INPUT_OPEN)
		chan_read_failed(c);
	chan_write_failed(c);
	s->chanid = -1;
}

void
session_free(Session *s)
{
	debug("session_free: session %d pid %d", s->self, s->pid);
	if (s->term)
		xfree(s->term);
	if (s->display)
		xfree(s->display);
	if (s->auth_data)
		xfree(s->auth_data);
	if (s->auth_proto)
		xfree(s->auth_proto);
	s->used = 0;
}

void
session_close(Session *s)
{
	session_pty_cleanup(s);
	session_free(s);
}

void
session_close_by_pid(pid_t pid, int status)
{
	Session *s = session_by_pid(pid);
	if (s == NULL) {
		debug("session_close_by_pid: no session for pid %d", s->pid);
		return;
	}
	if (s->chanid != -1)
		session_exit_message(s, status);
	session_close(s);
}

/*
 * this is called when a channel dies before
 * the session 'child' itself dies
 */
void
session_close_by_channel(int id, void *arg)
{
	Session *s = session_by_channel(id);
	if (s == NULL) {
		debug("session_close_by_channel: no session for channel %d", id);
		return;
	}
	/* disconnect channel */
	channel_cancel_cleanup(s->chanid);
	s->chanid = -1;

	debug("session_close_by_channel: channel %d kill %d", id, s->pid);
	if (s->pid == 0) {
		/* close session immediately */
		session_close(s);
	} else {
		/* notify child, delay session cleanup */
		if (kill(s->pid, (s->ttyfd == -1) ? SIGTERM : SIGHUP) < 0)
			error("session_close_by_channel: kill %d: %s",
			    s->pid, strerror(errno));
	}
}

void
do_authenticated2(void)
{
	/*
	 * Cancel the alarm we set to limit the time taken for
	 * authentication.
	 */
	alarm(0);
	log("do_authenticated2");
	server_loop2();
}