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
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
|
/* $OpenBSD: ssh.c,v 1.401 2014/02/26 20:18:37 djm Exp $ */
/* $FreeBSD$ */
/*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
* All rights reserved
* Ssh client program. This program can be used to log into a remote machine.
* The software supports strong authentication, encryption, and forwarding
* of X11, TCP/IP, and authentication connections.
*
* As far as I am concerned, the code I have written for this software
* can be used freely for any purpose. Any derived versions of this
* software must be clearly marked as such, and if the derived work is
* incompatible with the protocol description in the RFC file, it must be
* called by a name other than "ssh" or "Secure Shell".
*
* Copyright (c) 1999 Niels Provos. All rights reserved.
* Copyright (c) 2000, 2001, 2002, 2003 Markus Friedl. All rights reserved.
*
* Modified to work with SSL by Niels Provos <provos@citi.umich.edu>
* in Canada (German citizen).
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "includes.h"
__RCSID("$FreeBSD$");
#include <sys/types.h>
#ifdef HAVE_SYS_STAT_H
# include <sys/stat.h>
#endif
#include <sys/resource.h>
#include <sys/ioctl.h>
#include <sys/param.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <netdb.h>
#ifdef HAVE_PATHS_H
#include <paths.h>
#endif
#include <pwd.h>
#include <signal.h>
#include <stdarg.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <openssl/evp.h>
#include <openssl/err.h>
#include "openbsd-compat/openssl-compat.h"
#include "openbsd-compat/sys-queue.h"
#include "xmalloc.h"
#include "ssh.h"
#include "ssh1.h"
#include "ssh2.h"
#include "canohost.h"
#include "compat.h"
#include "cipher.h"
#include "packet.h"
#include "buffer.h"
#include "channels.h"
#include "key.h"
#include "authfd.h"
#include "authfile.h"
#include "pathnames.h"
#include "dispatch.h"
#include "clientloop.h"
#include "log.h"
#include "readconf.h"
#include "sshconnect.h"
#include "misc.h"
#include "kex.h"
#include "mac.h"
#include "sshpty.h"
#include "match.h"
#include "msg.h"
#include "uidswap.h"
#include "roaming.h"
#include "version.h"
#ifdef ENABLE_PKCS11
#include "ssh-pkcs11.h"
#endif
extern char *__progname;
/* Saves a copy of argv for setproctitle emulation */
#ifndef HAVE_SETPROCTITLE
static char **saved_av;
#endif
/* Flag indicating whether debug mode is on. May be set on the command line. */
int debug_flag = 0;
/* Flag indicating whether a tty should be requested */
int tty_flag = 0;
/* don't exec a shell */
int no_shell_flag = 0;
/*
* Flag indicating that nothing should be read from stdin. This can be set
* on the command line.
*/
int stdin_null_flag = 0;
/*
* Flag indicating that the current process should be backgrounded and
* a new slave launched in the foreground for ControlPersist.
*/
int need_controlpersist_detach = 0;
/* Copies of flags for ControlPersist foreground slave */
int ostdin_null_flag, ono_shell_flag, otty_flag, orequest_tty;
/*
* Flag indicating that ssh should fork after authentication. This is useful
* so that the passphrase can be entered manually, and then ssh goes to the
* background.
*/
int fork_after_authentication_flag = 0;
/* forward stdio to remote host and port */
char *stdio_forward_host = NULL;
int stdio_forward_port = 0;
/*
* General data structure for command line options and options configurable
* in configuration files. See readconf.h.
*/
Options options;
/* optional user configfile */
char *config = NULL;
/*
* Name of the host we are connecting to. This is the name given on the
* command line, or the HostName specified for the user-supplied name in a
* configuration file.
*/
char *host;
/* socket address the host resolves to */
struct sockaddr_storage hostaddr;
/* Private host keys. */
Sensitive sensitive_data;
/* Original real UID. */
uid_t original_real_uid;
uid_t original_effective_uid;
/* command to be executed */
Buffer command;
/* Should we execute a command or invoke a subsystem? */
int subsystem_flag = 0;
/* # of replies received for global requests */
static int remote_forward_confirms_received = 0;
/* mux.c */
extern int muxserver_sock;
extern u_int muxclient_command;
/* Prints a help message to the user. This function never returns. */
static void
usage(void)
{
fprintf(stderr,
"usage: ssh [-1246AaCfgKkMNnqsTtVvXxYy] [-b bind_address] [-c cipher_spec]\n"
" [-D [bind_address:]port] [-E log_file] [-e escape_char]\n"
" [-F configfile] [-I pkcs11] [-i identity_file]\n"
" [-L [bind_address:]port:host:hostport] [-l login_name] [-m mac_spec]\n"
" [-O ctl_cmd] [-o option] [-p port]\n"
" [-Q cipher | cipher-auth | mac | kex | key]\n"
" [-R [bind_address:]port:host:hostport] [-S ctl_path] [-W host:port]\n"
" [-w local_tun[:remote_tun]] [user@]hostname [command]\n"
);
exit(255);
}
static int ssh_session(void);
static int ssh_session2(void);
static void load_public_identity_files(void);
static void main_sigchld_handler(int);
/* from muxclient.c */
void muxclient(const char *);
void muxserver_listen(void);
/* ~/ expand a list of paths. NB. assumes path[n] is heap-allocated. */
static void
tilde_expand_paths(char **paths, u_int num_paths)
{
u_int i;
char *cp;
for (i = 0; i < num_paths; i++) {
cp = tilde_expand_filename(paths[i], original_real_uid);
free(paths[i]);
paths[i] = cp;
}
}
/*
* Attempt to resolve a host name / port to a set of addresses and
* optionally return any CNAMEs encountered along the way.
* Returns NULL on failure.
* NB. this function must operate with a options having undefined members.
*/
static struct addrinfo *
resolve_host(const char *name, int port, int logerr, char *cname, size_t clen)
{
char strport[NI_MAXSERV];
struct addrinfo hints, *res;
int gaierr, loglevel = SYSLOG_LEVEL_DEBUG1;
if (port <= 0)
port = default_ssh_port();
snprintf(strport, sizeof strport, "%u", port);
memset(&hints, 0, sizeof(hints));
hints.ai_family = options.address_family == -1 ?
AF_UNSPEC : options.address_family;
hints.ai_socktype = SOCK_STREAM;
if (cname != NULL)
hints.ai_flags = AI_CANONNAME;
if ((gaierr = getaddrinfo(name, strport, &hints, &res)) != 0) {
if (logerr || (gaierr != EAI_NONAME && gaierr != EAI_NODATA))
loglevel = SYSLOG_LEVEL_ERROR;
do_log2(loglevel, "%s: Could not resolve hostname %.100s: %s",
__progname, name, ssh_gai_strerror(gaierr));
return NULL;
}
if (cname != NULL && res->ai_canonname != NULL) {
if (strlcpy(cname, res->ai_canonname, clen) >= clen) {
error("%s: host \"%s\" cname \"%s\" too long (max %lu)",
__func__, name, res->ai_canonname, (u_long)clen);
if (clen > 0)
*cname = '\0';
}
}
return res;
}
/*
* Check whether the cname is a permitted replacement for the hostname
* and perform the replacement if it is.
* NB. this function must operate with a options having undefined members.
*/
static int
check_follow_cname(char **namep, const char *cname)
{
int i;
struct allowed_cname *rule;
if (*cname == '\0' || options.num_permitted_cnames == 0 ||
strcmp(*namep, cname) == 0)
return 0;
if (options.canonicalize_hostname == SSH_CANONICALISE_NO)
return 0;
/*
* Don't attempt to canonicalize names that will be interpreted by
* a proxy unless the user specifically requests so.
*/
if (!option_clear_or_none(options.proxy_command) &&
options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS)
return 0;
debug3("%s: check \"%s\" CNAME \"%s\"", __func__, *namep, cname);
for (i = 0; i < options.num_permitted_cnames; i++) {
rule = options.permitted_cnames + i;
if (match_pattern_list(*namep, rule->source_list,
strlen(rule->source_list), 1) != 1 ||
match_pattern_list(cname, rule->target_list,
strlen(rule->target_list), 1) != 1)
continue;
verbose("Canonicalized DNS aliased hostname "
"\"%s\" => \"%s\"", *namep, cname);
free(*namep);
*namep = xstrdup(cname);
return 1;
}
return 0;
}
/*
* Attempt to resolve the supplied hostname after applying the user's
* canonicalization rules. Returns the address list for the host or NULL
* if no name was found after canonicalization.
* NB. this function must operate with a options having undefined members.
*/
static struct addrinfo *
resolve_canonicalize(char **hostp, int port)
{
int i, ndots;
char *cp, *fullhost, cname_target[NI_MAXHOST];
struct addrinfo *addrs;
if (options.canonicalize_hostname == SSH_CANONICALISE_NO)
return NULL;
/*
* Don't attempt to canonicalize names that will be interpreted by
* a proxy unless the user specifically requests so.
*/
if (!option_clear_or_none(options.proxy_command) &&
options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS)
return NULL;
/* Don't apply canonicalization to sufficiently-qualified hostnames */
ndots = 0;
for (cp = *hostp; *cp != '\0'; cp++) {
if (*cp == '.')
ndots++;
}
if (ndots > options.canonicalize_max_dots) {
debug3("%s: not canonicalizing hostname \"%s\" (max dots %d)",
__func__, *hostp, options.canonicalize_max_dots);
return NULL;
}
/* Attempt each supplied suffix */
for (i = 0; i < options.num_canonical_domains; i++) {
*cname_target = '\0';
xasprintf(&fullhost, "%s.%s.", *hostp,
options.canonical_domains[i]);
debug3("%s: attempting \"%s\" => \"%s\"", __func__,
*hostp, fullhost);
if ((addrs = resolve_host(fullhost, port, 0,
cname_target, sizeof(cname_target))) == NULL) {
free(fullhost);
continue;
}
/* Remove trailing '.' */
fullhost[strlen(fullhost) - 1] = '\0';
/* Follow CNAME if requested */
if (!check_follow_cname(&fullhost, cname_target)) {
debug("Canonicalized hostname \"%s\" => \"%s\"",
*hostp, fullhost);
}
free(*hostp);
*hostp = fullhost;
return addrs;
}
if (!options.canonicalize_fallback_local)
fatal("%s: Could not resolve host \"%s\"", __progname, *hostp);
debug2("%s: host %s not found in any suffix", __func__, *hostp);
return NULL;
}
/*
* Read per-user configuration file. Ignore the system wide config
* file if the user specifies a config file on the command line.
*/
static void
process_config_files(struct passwd *pw)
{
char buf[MAXPATHLEN];
int r;
if (config != NULL) {
if (strcasecmp(config, "none") != 0 &&
!read_config_file(config, pw, host, &options,
SSHCONF_USERCONF))
fatal("Can't open user config file %.100s: "
"%.100s", config, strerror(errno));
} else {
r = snprintf(buf, sizeof buf, "%s/%s", pw->pw_dir,
_PATH_SSH_USER_CONFFILE);
if (r > 0 && (size_t)r < sizeof(buf))
(void)read_config_file(buf, pw, host, &options,
SSHCONF_CHECKPERM|SSHCONF_USERCONF);
/* Read systemwide configuration file after user config. */
(void)read_config_file(_PATH_HOST_CONFIG_FILE, pw, host,
&options, 0);
}
}
/*
* Main program for the ssh client.
*/
int
main(int ac, char **av)
{
int i, r, opt, exit_status, use_syslog;
char *p, *cp, *line, *argv0, buf[MAXPATHLEN], *host_arg, *logfile;
char thishost[NI_MAXHOST], shorthost[NI_MAXHOST], portstr[NI_MAXSERV];
char cname[NI_MAXHOST];
struct stat st;
struct passwd *pw;
int timeout_ms;
extern int optind, optreset;
extern char *optarg;
Forward fwd;
struct addrinfo *addrs = NULL;
/* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
sanitise_stdfd();
__progname = ssh_get_progname(av[0]);
#ifndef HAVE_SETPROCTITLE
/* Prepare for later setproctitle emulation */
/* Save argv so it isn't clobbered by setproctitle() emulation */
saved_av = xcalloc(ac + 1, sizeof(*saved_av));
for (i = 0; i < ac; i++)
saved_av[i] = xstrdup(av[i]);
saved_av[i] = NULL;
compat_init_setproctitle(ac, av);
av = saved_av;
#endif
/*
* Discard other fds that are hanging around. These can cause problem
* with backgrounded ssh processes started by ControlPersist.
*/
closefrom(STDERR_FILENO + 1);
/*
* Save the original real uid. It will be needed later (uid-swapping
* may clobber the real uid).
*/
original_real_uid = getuid();
original_effective_uid = geteuid();
/*
* Use uid-swapping to give up root privileges for the duration of
* option processing. We will re-instantiate the rights when we are
* ready to create the privileged port, and will permanently drop
* them when the port has been created (actually, when the connection
* has been made, as we may need to create the port several times).
*/
PRIV_END;
#ifdef HAVE_SETRLIMIT
/* If we are installed setuid root be careful to not drop core. */
if (original_real_uid != original_effective_uid) {
struct rlimit rlim;
rlim.rlim_cur = rlim.rlim_max = 0;
if (setrlimit(RLIMIT_CORE, &rlim) < 0)
fatal("setrlimit failed: %.100s", strerror(errno));
}
#endif
/* Get user data. */
pw = getpwuid(original_real_uid);
if (!pw) {
logit("No user exists for uid %lu", (u_long)original_real_uid);
exit(255);
}
/* Take a copy of the returned structure. */
pw = pwcopy(pw);
/*
* Set our umask to something reasonable, as some files are created
* with the default umask. This will make them world-readable but
* writable only by the owner, which is ok for all files for which we
* don't set the modes explicitly.
*/
umask(022);
/*
* Initialize option structure to indicate that no values have been
* set.
*/
initialize_options(&options);
/* Parse command-line arguments. */
host = NULL;
use_syslog = 0;
logfile = NULL;
argv0 = av[0];
again:
while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx"
"ACD:E:F:I:KL:MNO:PQ:R:S:TVw:W:XYy")) != -1) {
switch (opt) {
case '1':
options.protocol = SSH_PROTO_1;
break;
case '2':
options.protocol = SSH_PROTO_2;
break;
case '4':
options.address_family = AF_INET;
break;
case '6':
options.address_family = AF_INET6;
break;
case 'n':
stdin_null_flag = 1;
break;
case 'f':
fork_after_authentication_flag = 1;
stdin_null_flag = 1;
break;
case 'x':
options.forward_x11 = 0;
break;
case 'X':
options.forward_x11 = 1;
break;
case 'y':
use_syslog = 1;
break;
case 'E':
logfile = xstrdup(optarg);
break;
case 'Y':
options.forward_x11 = 1;
options.forward_x11_trusted = 1;
break;
case 'g':
options.gateway_ports = 1;
break;
case 'O':
if (stdio_forward_host != NULL)
fatal("Cannot specify multiplexing "
"command with -W");
else if (muxclient_command != 0)
fatal("Multiplexing command already specified");
if (strcmp(optarg, "check") == 0)
muxclient_command = SSHMUX_COMMAND_ALIVE_CHECK;
else if (strcmp(optarg, "forward") == 0)
muxclient_command = SSHMUX_COMMAND_FORWARD;
else if (strcmp(optarg, "exit") == 0)
muxclient_command = SSHMUX_COMMAND_TERMINATE;
else if (strcmp(optarg, "stop") == 0)
muxclient_command = SSHMUX_COMMAND_STOP;
else if (strcmp(optarg, "cancel") == 0)
muxclient_command = SSHMUX_COMMAND_CANCEL_FWD;
else
fatal("Invalid multiplex command.");
break;
case 'P': /* deprecated */
options.use_privileged_port = 0;
break;
case 'Q':
cp = NULL;
if (strcmp(optarg, "cipher") == 0)
cp = cipher_alg_list('\n', 0);
else if (strcmp(optarg, "cipher-auth") == 0)
cp = cipher_alg_list('\n', 1);
else if (strcmp(optarg, "mac") == 0)
cp = mac_alg_list('\n');
else if (strcmp(optarg, "kex") == 0)
cp = kex_alg_list('\n');
else if (strcmp(optarg, "key") == 0)
cp = key_alg_list(0, 0);
else if (strcmp(optarg, "key-cert") == 0)
cp = key_alg_list(1, 0);
else if (strcmp(optarg, "key-plain") == 0)
cp = key_alg_list(0, 1);
if (cp == NULL)
fatal("Unsupported query \"%s\"", optarg);
printf("%s\n", cp);
free(cp);
exit(0);
break;
case 'a':
options.forward_agent = 0;
break;
case 'A':
options.forward_agent = 1;
break;
case 'k':
options.gss_deleg_creds = 0;
break;
case 'K':
options.gss_authentication = 1;
options.gss_deleg_creds = 1;
break;
case 'i':
if (stat(optarg, &st) < 0) {
fprintf(stderr, "Warning: Identity file %s "
"not accessible: %s.\n", optarg,
strerror(errno));
break;
}
add_identity_file(&options, NULL, optarg, 1);
break;
case 'I':
#ifdef ENABLE_PKCS11
options.pkcs11_provider = xstrdup(optarg);
#else
fprintf(stderr, "no support for PKCS#11.\n");
#endif
break;
case 't':
if (options.request_tty == REQUEST_TTY_YES)
options.request_tty = REQUEST_TTY_FORCE;
else
options.request_tty = REQUEST_TTY_YES;
break;
case 'v':
if (debug_flag == 0) {
debug_flag = 1;
options.log_level = SYSLOG_LEVEL_DEBUG1;
} else {
if (options.log_level < SYSLOG_LEVEL_DEBUG3)
options.log_level++;
}
break;
case 'V':
if (options.version_addendum &&
*options.version_addendum != '\0')
fprintf(stderr, "%s%s %s, %s\n", SSH_RELEASE,
options.hpn_disabled ? "" : SSH_VERSION_HPN,
options.version_addendum,
SSLeay_version(SSLEAY_VERSION));
else
fprintf(stderr, "%s%s, %s\n", SSH_RELEASE,
options.hpn_disabled ? "" : SSH_VERSION_HPN,
SSLeay_version(SSLEAY_VERSION));
if (opt == 'V')
exit(0);
break;
case 'w':
if (options.tun_open == -1)
options.tun_open = SSH_TUNMODE_DEFAULT;
options.tun_local = a2tun(optarg, &options.tun_remote);
if (options.tun_local == SSH_TUNID_ERR) {
fprintf(stderr,
"Bad tun device '%s'\n", optarg);
exit(255);
}
break;
case 'W':
if (stdio_forward_host != NULL)
fatal("stdio forward already specified");
if (muxclient_command != 0)
fatal("Cannot specify stdio forward with -O");
if (parse_forward(&fwd, optarg, 1, 0)) {
stdio_forward_host = fwd.listen_host;
stdio_forward_port = fwd.listen_port;
free(fwd.connect_host);
} else {
fprintf(stderr,
"Bad stdio forwarding specification '%s'\n",
optarg);
exit(255);
}
options.request_tty = REQUEST_TTY_NO;
no_shell_flag = 1;
options.clear_forwardings = 1;
options.exit_on_forward_failure = 1;
break;
case 'q':
options.log_level = SYSLOG_LEVEL_QUIET;
break;
case 'e':
if (optarg[0] == '^' && optarg[2] == 0 &&
(u_char) optarg[1] >= 64 &&
(u_char) optarg[1] < 128)
options.escape_char = (u_char) optarg[1] & 31;
else if (strlen(optarg) == 1)
options.escape_char = (u_char) optarg[0];
else if (strcmp(optarg, "none") == 0)
options.escape_char = SSH_ESCAPECHAR_NONE;
else {
fprintf(stderr, "Bad escape character '%s'.\n",
optarg);
exit(255);
}
break;
case 'c':
if (ciphers_valid(optarg)) {
/* SSH2 only */
options.ciphers = xstrdup(optarg);
options.cipher = SSH_CIPHER_INVALID;
} else {
/* SSH1 only */
options.cipher = cipher_number(optarg);
if (options.cipher == -1) {
fprintf(stderr,
"Unknown cipher type '%s'\n",
optarg);
exit(255);
}
if (options.cipher == SSH_CIPHER_3DES)
options.ciphers = "3des-cbc";
else if (options.cipher == SSH_CIPHER_BLOWFISH)
options.ciphers = "blowfish-cbc";
else
options.ciphers = (char *)-1;
}
break;
case 'm':
if (mac_valid(optarg))
options.macs = xstrdup(optarg);
else {
fprintf(stderr, "Unknown mac type '%s'\n",
optarg);
exit(255);
}
break;
case 'M':
if (options.control_master == SSHCTL_MASTER_YES)
options.control_master = SSHCTL_MASTER_ASK;
else
options.control_master = SSHCTL_MASTER_YES;
break;
case 'p':
options.port = a2port(optarg);
if (options.port <= 0) {
fprintf(stderr, "Bad port '%s'\n", optarg);
exit(255);
}
break;
case 'l':
options.user = optarg;
break;
case 'L':
if (parse_forward(&fwd, optarg, 0, 0))
add_local_forward(&options, &fwd);
else {
fprintf(stderr,
"Bad local forwarding specification '%s'\n",
optarg);
exit(255);
}
break;
case 'R':
if (parse_forward(&fwd, optarg, 0, 1)) {
add_remote_forward(&options, &fwd);
} else {
fprintf(stderr,
"Bad remote forwarding specification "
"'%s'\n", optarg);
exit(255);
}
break;
case 'D':
if (parse_forward(&fwd, optarg, 1, 0)) {
add_local_forward(&options, &fwd);
} else {
fprintf(stderr,
"Bad dynamic forwarding specification "
"'%s'\n", optarg);
exit(255);
}
break;
case 'C':
options.compression = 1;
break;
case 'N':
no_shell_flag = 1;
options.request_tty = REQUEST_TTY_NO;
break;
case 'T':
options.request_tty = REQUEST_TTY_NO;
#ifdef NONE_CIPHER_ENABLED
/*
* Ensure that the user does not try to backdoor a
* NONE cipher switch on an interactive session by
* explicitly disabling it if the user asks for a
* session without a tty.
*/
options.none_switch = 0;
#endif
break;
case 'o':
line = xstrdup(optarg);
if (process_config_line(&options, pw, host ? host : "",
line, "command-line", 0, NULL, SSHCONF_USERCONF)
!= 0)
exit(255);
free(line);
break;
case 's':
subsystem_flag = 1;
break;
case 'S':
if (options.control_path != NULL)
free(options.control_path);
options.control_path = xstrdup(optarg);
break;
case 'b':
options.bind_address = optarg;
break;
case 'F':
config = optarg;
break;
default:
usage();
}
}
ac -= optind;
av += optind;
if (ac > 0 && !host) {
if (strrchr(*av, '@')) {
p = xstrdup(*av);
cp = strrchr(p, '@');
if (cp == NULL || cp == p)
usage();
options.user = p;
*cp = '\0';
host = xstrdup(++cp);
} else
host = xstrdup(*av);
if (ac > 1) {
optind = optreset = 1;
goto again;
}
ac--, av++;
}
/* Check that we got a host name. */
if (!host)
usage();
host_arg = xstrdup(host);
OpenSSL_add_all_algorithms();
ERR_load_crypto_strings();
/* Initialize the command to execute on remote host. */
buffer_init(&command);
/*
* Save the command to execute on the remote host in a buffer. There
* is no limit on the length of the command, except by the maximum
* packet size. Also sets the tty flag if there is no command.
*/
if (!ac) {
/* No command specified - execute shell on a tty. */
if (subsystem_flag) {
fprintf(stderr,
"You must specify a subsystem to invoke.\n");
usage();
}
} else {
/* A command has been specified. Store it into the buffer. */
for (i = 0; i < ac; i++) {
if (i)
buffer_append(&command, " ", 1);
buffer_append(&command, av[i], strlen(av[i]));
}
}
/* Cannot fork to background if no command. */
if (fork_after_authentication_flag && buffer_len(&command) == 0 &&
!no_shell_flag)
fatal("Cannot fork into background without a command "
"to execute.");
/*
* Initialize "log" output. Since we are the client all output
* goes to stderr unless otherwise specified by -y or -E.
*/
if (use_syslog && logfile != NULL)
fatal("Can't specify both -y and -E");
if (logfile != NULL) {
log_redirect_stderr_to(logfile);
free(logfile);
}
log_init(argv0,
options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level,
SYSLOG_FACILITY_USER, !use_syslog);
if (debug_flag)
logit("%s, %s", SSH_VERSION, SSLeay_version(SSLEAY_VERSION));
/* Parse the configuration files */
process_config_files(pw);
/* Hostname canonicalisation needs a few options filled. */
fill_default_options_for_canonicalization(&options);
/* If the user has replaced the hostname then take it into use now */
if (options.hostname != NULL) {
/* NB. Please keep in sync with readconf.c:match_cfg_line() */
cp = percent_expand(options.hostname,
"h", host, (char *)NULL);
free(host);
host = cp;
}
/* If canonicalization requested then try to apply it */
lowercase(host);
if (options.canonicalize_hostname != SSH_CANONICALISE_NO)
addrs = resolve_canonicalize(&host, options.port);
/*
* If CanonicalizePermittedCNAMEs have been specified but
* other canonicalization did not happen (by not being requested
* or by failing with fallback) then the hostname may still be changed
* as a result of CNAME following.
*
* Try to resolve the bare hostname name using the system resolver's
* usual search rules and then apply the CNAME follow rules.
*
* Skip the lookup if a ProxyCommand is being used unless the user
* has specifically requested canonicalisation for this case via
* CanonicalizeHostname=always
*/
if (addrs == NULL && options.num_permitted_cnames != 0 &&
(option_clear_or_none(options.proxy_command) ||
options.canonicalize_hostname == SSH_CANONICALISE_ALWAYS)) {
if ((addrs = resolve_host(host, options.port, 1,
cname, sizeof(cname))) == NULL)
cleanup_exit(255); /* resolve_host logs the error */
check_follow_cname(&host, cname);
}
/*
* If the target hostname has changed as a result of canonicalisation
* then re-parse the configuration files as new stanzas may match.
*/
if (strcasecmp(host_arg, host) != 0) {
debug("Hostname has changed; re-reading configuration");
process_config_files(pw);
}
/* Fill configuration defaults. */
fill_default_options(&options);
if (options.port == 0)
options.port = default_ssh_port();
channel_set_af(options.address_family);
/* Tidy and check options */
if (options.host_key_alias != NULL)
lowercase(options.host_key_alias);
if (options.proxy_command != NULL &&
strcmp(options.proxy_command, "-") == 0 &&
options.proxy_use_fdpass)
fatal("ProxyCommand=- and ProxyUseFDPass are incompatible");
#ifndef HAVE_CYGWIN
if (original_effective_uid != 0)
options.use_privileged_port = 0;
#endif
/* reinit */
log_init(argv0, options.log_level, SYSLOG_FACILITY_USER, !use_syslog);
if (options.request_tty == REQUEST_TTY_YES ||
options.request_tty == REQUEST_TTY_FORCE)
tty_flag = 1;
/* Allocate a tty by default if no command specified. */
if (buffer_len(&command) == 0)
tty_flag = options.request_tty != REQUEST_TTY_NO;
/* Force no tty */
if (options.request_tty == REQUEST_TTY_NO || muxclient_command != 0)
tty_flag = 0;
/* Do not allocate a tty if stdin is not a tty. */
if ((!isatty(fileno(stdin)) || stdin_null_flag) &&
options.request_tty != REQUEST_TTY_FORCE) {
if (tty_flag)
logit("Pseudo-terminal will not be allocated because "
"stdin is not a terminal.");
tty_flag = 0;
}
seed_rng();
if (options.user == NULL)
options.user = xstrdup(pw->pw_name);
if (gethostname(thishost, sizeof(thishost)) == -1)
fatal("gethostname: %s", strerror(errno));
strlcpy(shorthost, thishost, sizeof(shorthost));
shorthost[strcspn(thishost, ".")] = '\0';
snprintf(portstr, sizeof(portstr), "%d", options.port);
if (options.local_command != NULL) {
debug3("expanding LocalCommand: %s", options.local_command);
cp = options.local_command;
options.local_command = percent_expand(cp, "d", pw->pw_dir,
"h", host, "l", thishost, "n", host_arg, "r", options.user,
"p", portstr, "u", pw->pw_name, "L", shorthost,
(char *)NULL);
debug3("expanded LocalCommand: %s", options.local_command);
free(cp);
}
if (options.control_path != NULL) {
cp = tilde_expand_filename(options.control_path,
original_real_uid);
free(options.control_path);
options.control_path = percent_expand(cp, "h", host,
"l", thishost, "n", host_arg, "r", options.user,
"p", portstr, "u", pw->pw_name, "L", shorthost,
(char *)NULL);
free(cp);
}
if (muxclient_command != 0 && options.control_path == NULL)
fatal("No ControlPath specified for \"-O\" command");
if (options.control_path != NULL)
muxclient(options.control_path);
/*
* If hostname canonicalisation was not enabled, then we may not
* have yet resolved the hostname. Do so now.
*/
if (addrs == NULL && options.proxy_command == NULL) {
if ((addrs = resolve_host(host, options.port, 1,
cname, sizeof(cname))) == NULL)
cleanup_exit(255); /* resolve_host logs the error */
}
timeout_ms = options.connection_timeout * 1000;
/* Open a connection to the remote host. */
if (ssh_connect(host, addrs, &hostaddr, options.port,
options.address_family, options.connection_attempts,
&timeout_ms, options.tcp_keep_alive,
options.use_privileged_port) != 0)
exit(255);
if (addrs != NULL)
freeaddrinfo(addrs);
packet_set_timeout(options.server_alive_interval,
options.server_alive_count_max);
if (timeout_ms > 0)
debug3("timeout: %d ms remain after connect", timeout_ms);
/*
* If we successfully made the connection, load the host private key
* in case we will need it later for combined rsa-rhosts
* authentication. This must be done before releasing extra
* privileges, because the file is only readable by root.
* If we cannot access the private keys, load the public keys
* instead and try to execute the ssh-keysign helper instead.
*/
sensitive_data.nkeys = 0;
sensitive_data.keys = NULL;
sensitive_data.external_keysign = 0;
if (options.rhosts_rsa_authentication ||
options.hostbased_authentication) {
sensitive_data.nkeys = 9;
sensitive_data.keys = xcalloc(sensitive_data.nkeys,
sizeof(Key));
for (i = 0; i < sensitive_data.nkeys; i++)
sensitive_data.keys[i] = NULL;
PRIV_START;
sensitive_data.keys[0] = key_load_private_type(KEY_RSA1,
_PATH_HOST_KEY_FILE, "", NULL, NULL);
sensitive_data.keys[1] = key_load_private_cert(KEY_DSA,
_PATH_HOST_DSA_KEY_FILE, "", NULL);
#ifdef OPENSSL_HAS_ECC
sensitive_data.keys[2] = key_load_private_cert(KEY_ECDSA,
_PATH_HOST_ECDSA_KEY_FILE, "", NULL);
#endif
sensitive_data.keys[3] = key_load_private_cert(KEY_RSA,
_PATH_HOST_RSA_KEY_FILE, "", NULL);
sensitive_data.keys[4] = key_load_private_cert(KEY_ED25519,
_PATH_HOST_ED25519_KEY_FILE, "", NULL);
sensitive_data.keys[5] = key_load_private_type(KEY_DSA,
_PATH_HOST_DSA_KEY_FILE, "", NULL, NULL);
#ifdef OPENSSL_HAS_ECC
sensitive_data.keys[6] = key_load_private_type(KEY_ECDSA,
_PATH_HOST_ECDSA_KEY_FILE, "", NULL, NULL);
#endif
sensitive_data.keys[7] = key_load_private_type(KEY_RSA,
_PATH_HOST_RSA_KEY_FILE, "", NULL, NULL);
sensitive_data.keys[8] = key_load_private_type(KEY_ED25519,
_PATH_HOST_ED25519_KEY_FILE, "", NULL, NULL);
PRIV_END;
if (options.hostbased_authentication == 1 &&
sensitive_data.keys[0] == NULL &&
sensitive_data.keys[5] == NULL &&
sensitive_data.keys[6] == NULL &&
sensitive_data.keys[7] == NULL &&
sensitive_data.keys[8] == NULL) {
sensitive_data.keys[1] = key_load_cert(
_PATH_HOST_DSA_KEY_FILE);
#ifdef OPENSSL_HAS_ECC
sensitive_data.keys[2] = key_load_cert(
_PATH_HOST_ECDSA_KEY_FILE);
#endif
sensitive_data.keys[3] = key_load_cert(
_PATH_HOST_RSA_KEY_FILE);
sensitive_data.keys[4] = key_load_cert(
_PATH_HOST_ED25519_KEY_FILE);
sensitive_data.keys[5] = key_load_public(
_PATH_HOST_DSA_KEY_FILE, NULL);
#ifdef OPENSSL_HAS_ECC
sensitive_data.keys[6] = key_load_public(
_PATH_HOST_ECDSA_KEY_FILE, NULL);
#endif
sensitive_data.keys[7] = key_load_public(
_PATH_HOST_RSA_KEY_FILE, NULL);
sensitive_data.keys[8] = key_load_public(
_PATH_HOST_ED25519_KEY_FILE, NULL);
sensitive_data.external_keysign = 1;
}
}
/*
* Get rid of any extra privileges that we may have. We will no
* longer need them. Also, extra privileges could make it very hard
* to read identity files and other non-world-readable files from the
* user's home directory if it happens to be on a NFS volume where
* root is mapped to nobody.
*/
if (original_effective_uid == 0) {
PRIV_START;
permanently_set_uid(pw);
}
/*
* Now that we are back to our own permissions, create ~/.ssh
* directory if it doesn't already exist.
*/
if (config == NULL) {
r = snprintf(buf, sizeof buf, "%s%s%s", pw->pw_dir,
strcmp(pw->pw_dir, "/") ? "/" : "", _PATH_SSH_USER_DIR);
if (r > 0 && (size_t)r < sizeof(buf) && stat(buf, &st) < 0) {
#ifdef WITH_SELINUX
ssh_selinux_setfscreatecon(buf);
#endif
if (mkdir(buf, 0700) < 0)
error("Could not create directory '%.200s'.",
buf);
#ifdef WITH_SELINUX
ssh_selinux_setfscreatecon(NULL);
#endif
}
}
/* load options.identity_files */
load_public_identity_files();
/* Expand ~ in known host file names. */
tilde_expand_paths(options.system_hostfiles,
options.num_system_hostfiles);
tilde_expand_paths(options.user_hostfiles, options.num_user_hostfiles);
signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */
signal(SIGCHLD, main_sigchld_handler);
/* Log into the remote system. Never returns if the login fails. */
ssh_login(&sensitive_data, host, (struct sockaddr *)&hostaddr,
options.port, pw, timeout_ms);
if (packet_connection_is_on_socket()) {
verbose("Authenticated to %s ([%s]:%d).", host,
get_remote_ipaddr(), get_remote_port());
} else {
verbose("Authenticated to %s (via proxy).", host);
}
/* We no longer need the private host keys. Clear them now. */
if (sensitive_data.nkeys != 0) {
for (i = 0; i < sensitive_data.nkeys; i++) {
if (sensitive_data.keys[i] != NULL) {
/* Destroys contents safely */
debug3("clear hostkey %d", i);
key_free(sensitive_data.keys[i]);
sensitive_data.keys[i] = NULL;
}
}
free(sensitive_data.keys);
}
for (i = 0; i < options.num_identity_files; i++) {
free(options.identity_files[i]);
options.identity_files[i] = NULL;
if (options.identity_keys[i]) {
key_free(options.identity_keys[i]);
options.identity_keys[i] = NULL;
}
}
exit_status = compat20 ? ssh_session2() : ssh_session();
packet_close();
if (options.control_path != NULL && muxserver_sock != -1)
unlink(options.control_path);
/* Kill ProxyCommand if it is running. */
ssh_kill_proxy_command();
return exit_status;
}
static void
control_persist_detach(void)
{
pid_t pid;
int devnull;
debug("%s: backgrounding master process", __func__);
/*
* master (current process) into the background, and make the
* foreground process a client of the backgrounded master.
*/
switch ((pid = fork())) {
case -1:
fatal("%s: fork: %s", __func__, strerror(errno));
case 0:
/* Child: master process continues mainloop */
break;
default:
/* Parent: set up mux slave to connect to backgrounded master */
debug2("%s: background process is %ld", __func__, (long)pid);
stdin_null_flag = ostdin_null_flag;
options.request_tty = orequest_tty;
tty_flag = otty_flag;
close(muxserver_sock);
muxserver_sock = -1;
options.control_master = SSHCTL_MASTER_NO;
muxclient(options.control_path);
/* muxclient() doesn't return on success. */
fatal("Failed to connect to new control master");
}
if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1) {
error("%s: open(\"/dev/null\"): %s", __func__,
strerror(errno));
} else {
if (dup2(devnull, STDIN_FILENO) == -1 ||
dup2(devnull, STDOUT_FILENO) == -1)
error("%s: dup2: %s", __func__, strerror(errno));
if (devnull > STDERR_FILENO)
close(devnull);
}
daemon(1, 1);
setproctitle("%s [mux]", options.control_path);
}
/* Do fork() after authentication. Used by "ssh -f" */
static void
fork_postauth(void)
{
if (need_controlpersist_detach)
control_persist_detach();
debug("forking to background");
fork_after_authentication_flag = 0;
if (daemon(1, 1) < 0)
fatal("daemon() failed: %.200s", strerror(errno));
}
/* Callback for remote forward global requests */
static void
ssh_confirm_remote_forward(int type, u_int32_t seq, void *ctxt)
{
Forward *rfwd = (Forward *)ctxt;
/* XXX verbose() on failure? */
debug("remote forward %s for: listen %d, connect %s:%d",
type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure",
rfwd->listen_port, rfwd->connect_host, rfwd->connect_port);
if (rfwd->listen_port == 0) {
if (type == SSH2_MSG_REQUEST_SUCCESS) {
rfwd->allocated_port = packet_get_int();
logit("Allocated port %u for remote forward to %s:%d",
rfwd->allocated_port,
rfwd->connect_host, rfwd->connect_port);
channel_update_permitted_opens(rfwd->handle,
rfwd->allocated_port);
} else {
channel_update_permitted_opens(rfwd->handle, -1);
}
}
if (type == SSH2_MSG_REQUEST_FAILURE) {
if (options.exit_on_forward_failure)
fatal("Error: remote port forwarding failed for "
"listen port %d", rfwd->listen_port);
else
logit("Warning: remote port forwarding failed for "
"listen port %d", rfwd->listen_port);
}
if (++remote_forward_confirms_received == options.num_remote_forwards) {
debug("All remote forwarding requests processed");
if (fork_after_authentication_flag)
fork_postauth();
}
}
static void
client_cleanup_stdio_fwd(int id, void *arg)
{
debug("stdio forwarding: done");
cleanup_exit(0);
}
static void
ssh_init_stdio_forwarding(void)
{
Channel *c;
int in, out;
if (stdio_forward_host == NULL)
return;
if (!compat20)
fatal("stdio forwarding require Protocol 2");
debug3("%s: %s:%d", __func__, stdio_forward_host, stdio_forward_port);
if ((in = dup(STDIN_FILENO)) < 0 ||
(out = dup(STDOUT_FILENO)) < 0)
fatal("channel_connect_stdio_fwd: dup() in/out failed");
if ((c = channel_connect_stdio_fwd(stdio_forward_host,
stdio_forward_port, in, out)) == NULL)
fatal("%s: channel_connect_stdio_fwd failed", __func__);
channel_register_cleanup(c->self, client_cleanup_stdio_fwd, 0);
}
static void
ssh_init_forwarding(void)
{
int success = 0;
int i;
/* Initiate local TCP/IP port forwardings. */
for (i = 0; i < options.num_local_forwards; i++) {
debug("Local connections to %.200s:%d forwarded to remote "
"address %.200s:%d",
(options.local_forwards[i].listen_host == NULL) ?
(options.gateway_ports ? "*" : "LOCALHOST") :
options.local_forwards[i].listen_host,
options.local_forwards[i].listen_port,
options.local_forwards[i].connect_host,
options.local_forwards[i].connect_port);
success += channel_setup_local_fwd_listener(
options.local_forwards[i].listen_host,
options.local_forwards[i].listen_port,
options.local_forwards[i].connect_host,
options.local_forwards[i].connect_port,
options.gateway_ports);
}
if (i > 0 && success != i && options.exit_on_forward_failure)
fatal("Could not request local forwarding.");
if (i > 0 && success == 0)
error("Could not request local forwarding.");
/* Initiate remote TCP/IP port forwardings. */
for (i = 0; i < options.num_remote_forwards; i++) {
debug("Remote connections from %.200s:%d forwarded to "
"local address %.200s:%d",
(options.remote_forwards[i].listen_host == NULL) ?
"LOCALHOST" : options.remote_forwards[i].listen_host,
options.remote_forwards[i].listen_port,
options.remote_forwards[i].connect_host,
options.remote_forwards[i].connect_port);
options.remote_forwards[i].handle =
channel_request_remote_forwarding(
options.remote_forwards[i].listen_host,
options.remote_forwards[i].listen_port,
options.remote_forwards[i].connect_host,
options.remote_forwards[i].connect_port);
if (options.remote_forwards[i].handle < 0) {
if (options.exit_on_forward_failure)
fatal("Could not request remote forwarding.");
else
logit("Warning: Could not request remote "
"forwarding.");
} else {
client_register_global_confirm(ssh_confirm_remote_forward,
&options.remote_forwards[i]);
}
}
/* Initiate tunnel forwarding. */
if (options.tun_open != SSH_TUNMODE_NO) {
if (client_request_tun_fwd(options.tun_open,
options.tun_local, options.tun_remote) == -1) {
if (options.exit_on_forward_failure)
fatal("Could not request tunnel forwarding.");
else
error("Could not request tunnel forwarding.");
}
}
}
static void
check_agent_present(void)
{
if (options.forward_agent) {
/* Clear agent forwarding if we don't have an agent. */
if (!ssh_agent_present())
options.forward_agent = 0;
}
}
static int
ssh_session(void)
{
int type;
int interactive = 0;
int have_tty = 0;
struct winsize ws;
char *cp;
const char *display;
/* Enable compression if requested. */
if (options.compression) {
debug("Requesting compression at level %d.",
options.compression_level);
if (options.compression_level < 1 ||
options.compression_level > 9)
fatal("Compression level must be from 1 (fast) to "
"9 (slow, best).");
/* Send the request. */
packet_start(SSH_CMSG_REQUEST_COMPRESSION);
packet_put_int(options.compression_level);
packet_send();
packet_write_wait();
type = packet_read();
if (type == SSH_SMSG_SUCCESS)
packet_start_compression(options.compression_level);
else if (type == SSH_SMSG_FAILURE)
logit("Warning: Remote host refused compression.");
else
packet_disconnect("Protocol error waiting for "
"compression response.");
}
/* Allocate a pseudo tty if appropriate. */
if (tty_flag) {
debug("Requesting pty.");
/* Start the packet. */
packet_start(SSH_CMSG_REQUEST_PTY);
/* Store TERM in the packet. There is no limit on the
length of the string. */
cp = getenv("TERM");
if (!cp)
cp = "";
packet_put_cstring(cp);
/* Store window size in the packet. */
if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
memset(&ws, 0, sizeof(ws));
packet_put_int((u_int)ws.ws_row);
packet_put_int((u_int)ws.ws_col);
packet_put_int((u_int)ws.ws_xpixel);
packet_put_int((u_int)ws.ws_ypixel);
/* Store tty modes in the packet. */
tty_make_modes(fileno(stdin), NULL);
/* Send the packet, and wait for it to leave. */
packet_send();
packet_write_wait();
/* Read response from the server. */
type = packet_read();
if (type == SSH_SMSG_SUCCESS) {
interactive = 1;
have_tty = 1;
} else if (type == SSH_SMSG_FAILURE)
logit("Warning: Remote host failed or refused to "
"allocate a pseudo tty.");
else
packet_disconnect("Protocol error waiting for pty "
"request response.");
}
/* Request X11 forwarding if enabled and DISPLAY is set. */
display = getenv("DISPLAY");
if (options.forward_x11 && display != NULL) {
char *proto, *data;
/* Get reasonable local authentication information. */
client_x11_get_proto(display, options.xauth_location,
options.forward_x11_trusted,
options.forward_x11_timeout,
&proto, &data);
/* Request forwarding with authentication spoofing. */
debug("Requesting X11 forwarding with authentication "
"spoofing.");
x11_request_forwarding_with_spoofing(0, display, proto,
data, 0);
/* Read response from the server. */
type = packet_read();
if (type == SSH_SMSG_SUCCESS) {
interactive = 1;
} else if (type == SSH_SMSG_FAILURE) {
logit("Warning: Remote host denied X11 forwarding.");
} else {
packet_disconnect("Protocol error waiting for X11 "
"forwarding");
}
}
/* Tell the packet module whether this is an interactive session. */
packet_set_interactive(interactive,
options.ip_qos_interactive, options.ip_qos_bulk);
/* Request authentication agent forwarding if appropriate. */
check_agent_present();
if (options.forward_agent) {
debug("Requesting authentication agent forwarding.");
auth_request_forwarding();
/* Read response from the server. */
type = packet_read();
packet_check_eom();
if (type != SSH_SMSG_SUCCESS)
logit("Warning: Remote host denied authentication agent forwarding.");
}
/* Initiate port forwardings. */
ssh_init_stdio_forwarding();
ssh_init_forwarding();
/* Execute a local command */
if (options.local_command != NULL &&
options.permit_local_command)
ssh_local_cmd(options.local_command);
/*
* If requested and we are not interested in replies to remote
* forwarding requests, then let ssh continue in the background.
*/
if (fork_after_authentication_flag) {
if (options.exit_on_forward_failure &&
options.num_remote_forwards > 0) {
debug("deferring postauth fork until remote forward "
"confirmation received");
} else
fork_postauth();
}
/*
* If a command was specified on the command line, execute the
* command now. Otherwise request the server to start a shell.
*/
if (buffer_len(&command) > 0) {
int len = buffer_len(&command);
if (len > 900)
len = 900;
debug("Sending command: %.*s", len,
(u_char *)buffer_ptr(&command));
packet_start(SSH_CMSG_EXEC_CMD);
packet_put_string(buffer_ptr(&command), buffer_len(&command));
packet_send();
packet_write_wait();
} else {
debug("Requesting shell.");
packet_start(SSH_CMSG_EXEC_SHELL);
packet_send();
packet_write_wait();
}
/* Enter the interactive session. */
return client_loop(have_tty, tty_flag ?
options.escape_char : SSH_ESCAPECHAR_NONE, 0);
}
/* request pty/x11/agent/tcpfwd/shell for channel */
static void
ssh_session2_setup(int id, int success, void *arg)
{
extern char **environ;
const char *display;
int interactive = tty_flag;
if (!success)
return; /* No need for error message, channels code sens one */
display = getenv("DISPLAY");
if (options.forward_x11 && display != NULL) {
char *proto, *data;
/* Get reasonable local authentication information. */
client_x11_get_proto(display, options.xauth_location,
options.forward_x11_trusted,
options.forward_x11_timeout, &proto, &data);
/* Request forwarding with authentication spoofing. */
debug("Requesting X11 forwarding with authentication "
"spoofing.");
x11_request_forwarding_with_spoofing(id, display, proto,
data, 1);
client_expect_confirm(id, "X11 forwarding", CONFIRM_WARN);
/* XXX exit_on_forward_failure */
interactive = 1;
}
check_agent_present();
if (options.forward_agent) {
debug("Requesting authentication agent forwarding.");
channel_request_start(id, "auth-agent-req@openssh.com", 0);
packet_send();
}
/* Tell the packet module whether this is an interactive session. */
packet_set_interactive(interactive,
options.ip_qos_interactive, options.ip_qos_bulk);
client_session2_setup(id, tty_flag, subsystem_flag, getenv("TERM"),
NULL, fileno(stdin), &command, environ);
}
/* open new channel for a session */
static int
ssh_session2_open(void)
{
Channel *c;
int window, packetmax, in, out, err;
if (stdin_null_flag) {
in = open(_PATH_DEVNULL, O_RDONLY);
} else {
in = dup(STDIN_FILENO);
}
out = dup(STDOUT_FILENO);
err = dup(STDERR_FILENO);
if (in < 0 || out < 0 || err < 0)
fatal("dup() in/out/err failed");
/* enable nonblocking unless tty */
if (!isatty(in))
set_nonblock(in);
if (!isatty(out))
set_nonblock(out);
if (!isatty(err))
set_nonblock(err);
/*
* We need to check to see what to do about buffer sizes here.
* - In an HPN to non-HPN connection we want to limit the window size to
* something reasonable in case the far side has the large window bug.
* - In an HPN to HPN connection we want to use the max window size but
* allow the user to override it.
* - Lastly if HPN is disabled then use the ssh standard window size.
*
* We cannot just do a getsockopt() here and set the ssh window to that
* as in case of autotuning of socket buffers the window would get stuck
* at the initial buffer size, generally less than 96k. Therefore we
* need to set the maximum ssh window size to the maximum HPN buffer
* size unless the user has set TcpRcvBufPoll to no. In that case we
* can just set the window to the minimum of HPN buffer size and TCP
* receive buffer size.
*/
if (tty_flag)
options.hpn_buffer_size = CHAN_SES_WINDOW_DEFAULT;
else
options.hpn_buffer_size = CHAN_HPN_MIN_WINDOW_DEFAULT;
if (datafellows & SSH_BUG_LARGEWINDOW) {
debug("HPN to Non-HPN Connection");
} else if (options.tcp_rcv_buf_poll <= 0) {
sock_get_rcvbuf(&options.hpn_buffer_size, 0);
debug("HPNBufferSize set to TCP RWIN: %d",
options.hpn_buffer_size);
} else if (options.tcp_rcv_buf > 0) {
sock_get_rcvbuf(&options.hpn_buffer_size,
options.tcp_rcv_buf);
debug("HPNBufferSize set to user TCPRcvBuf: %d",
options.hpn_buffer_size);
}
debug("Final hpn_buffer_size = %d", options.hpn_buffer_size);
channel_set_hpn(options.hpn_disabled, options.hpn_buffer_size);
window = options.hpn_buffer_size;
packetmax = CHAN_SES_PACKET_DEFAULT;
if (tty_flag) {
window = CHAN_SES_WINDOW_DEFAULT;
window >>= 1;
packetmax >>= 1;
}
c = channel_new(
"session", SSH_CHANNEL_OPENING, in, out, err,
window, packetmax, CHAN_EXTENDED_WRITE,
"client-session", /*nonblock*/0);
if (!options.hpn_disabled && options.tcp_rcv_buf_poll > 0) {
c->dynamic_window = 1;
debug("Enabled Dynamic Window Scaling\n");
}
debug3("ssh_session2_open: channel_new: %d", c->self);
channel_send_open(c->self);
if (!no_shell_flag)
channel_register_open_confirm(c->self,
ssh_session2_setup, NULL);
return c->self;
}
static int
ssh_session2(void)
{
int id = -1;
/* XXX should be pre-session */
if (!options.control_persist)
ssh_init_stdio_forwarding();
ssh_init_forwarding();
/* Start listening for multiplex clients */
muxserver_listen();
/*
* If we are in control persist mode and have a working mux listen
* socket, then prepare to background ourselves and have a foreground
* client attach as a control slave.
* NB. we must save copies of the flags that we override for
* the backgrounding, since we defer attachment of the slave until
* after the connection is fully established (in particular,
* async rfwd replies have been received for ExitOnForwardFailure).
*/
if (options.control_persist && muxserver_sock != -1) {
ostdin_null_flag = stdin_null_flag;
ono_shell_flag = no_shell_flag;
orequest_tty = options.request_tty;
otty_flag = tty_flag;
stdin_null_flag = 1;
no_shell_flag = 1;
tty_flag = 0;
if (!fork_after_authentication_flag)
need_controlpersist_detach = 1;
fork_after_authentication_flag = 1;
}
/*
* ControlPersist mux listen socket setup failed, attempt the
* stdio forward setup that we skipped earlier.
*/
if (options.control_persist && muxserver_sock == -1)
ssh_init_stdio_forwarding();
if (!no_shell_flag || (datafellows & SSH_BUG_DUMMYCHAN))
id = ssh_session2_open();
else {
packet_set_interactive(
options.control_master == SSHCTL_MASTER_NO,
options.ip_qos_interactive, options.ip_qos_bulk);
}
/* If we don't expect to open a new session, then disallow it */
if (options.control_master == SSHCTL_MASTER_NO &&
(datafellows & SSH_NEW_OPENSSH)) {
debug("Requesting no-more-sessions@openssh.com");
packet_start(SSH2_MSG_GLOBAL_REQUEST);
packet_put_cstring("no-more-sessions@openssh.com");
packet_put_char(0);
packet_send();
}
/* Execute a local command */
if (options.local_command != NULL &&
options.permit_local_command)
ssh_local_cmd(options.local_command);
/*
* If requested and we are not interested in replies to remote
* forwarding requests, then let ssh continue in the background.
*/
if (fork_after_authentication_flag) {
if (options.exit_on_forward_failure &&
options.num_remote_forwards > 0) {
debug("deferring postauth fork until remote forward "
"confirmation received");
} else
fork_postauth();
}
if (options.use_roaming)
request_roaming();
return client_loop(tty_flag, tty_flag ?
options.escape_char : SSH_ESCAPECHAR_NONE, id);
}
static void
load_public_identity_files(void)
{
char *filename, *cp, thishost[NI_MAXHOST];
char *pwdir = NULL, *pwname = NULL;
int i = 0;
Key *public;
struct passwd *pw;
u_int n_ids;
char *identity_files[SSH_MAX_IDENTITY_FILES];
Key *identity_keys[SSH_MAX_IDENTITY_FILES];
#ifdef ENABLE_PKCS11
Key **keys;
int nkeys;
#endif /* PKCS11 */
n_ids = 0;
memset(identity_files, 0, sizeof(identity_files));
memset(identity_keys, 0, sizeof(identity_keys));
#ifdef ENABLE_PKCS11
if (options.pkcs11_provider != NULL &&
options.num_identity_files < SSH_MAX_IDENTITY_FILES &&
(pkcs11_init(!options.batch_mode) == 0) &&
(nkeys = pkcs11_add_provider(options.pkcs11_provider, NULL,
&keys)) > 0) {
for (i = 0; i < nkeys; i++) {
if (n_ids >= SSH_MAX_IDENTITY_FILES) {
key_free(keys[i]);
continue;
}
identity_keys[n_ids] = keys[i];
identity_files[n_ids] =
xstrdup(options.pkcs11_provider); /* XXX */
n_ids++;
}
free(keys);
}
#endif /* ENABLE_PKCS11 */
if ((pw = getpwuid(original_real_uid)) == NULL)
fatal("load_public_identity_files: getpwuid failed");
pwname = xstrdup(pw->pw_name);
pwdir = xstrdup(pw->pw_dir);
if (gethostname(thishost, sizeof(thishost)) == -1)
fatal("load_public_identity_files: gethostname: %s",
strerror(errno));
for (i = 0; i < options.num_identity_files; i++) {
if (n_ids >= SSH_MAX_IDENTITY_FILES ||
strcasecmp(options.identity_files[i], "none") == 0) {
free(options.identity_files[i]);
continue;
}
cp = tilde_expand_filename(options.identity_files[i],
original_real_uid);
filename = percent_expand(cp, "d", pwdir,
"u", pwname, "l", thishost, "h", host,
"r", options.user, (char *)NULL);
free(cp);
public = key_load_public(filename, NULL);
debug("identity file %s type %d", filename,
public ? public->type : -1);
free(options.identity_files[i]);
identity_files[n_ids] = filename;
identity_keys[n_ids] = public;
if (++n_ids >= SSH_MAX_IDENTITY_FILES)
continue;
/* Try to add the certificate variant too */
xasprintf(&cp, "%s-cert", filename);
public = key_load_public(cp, NULL);
debug("identity file %s type %d", cp,
public ? public->type : -1);
if (public == NULL) {
free(cp);
continue;
}
if (!key_is_cert(public)) {
debug("%s: key %s type %s is not a certificate",
__func__, cp, key_type(public));
key_free(public);
free(cp);
continue;
}
identity_keys[n_ids] = public;
/* point to the original path, most likely the private key */
identity_files[n_ids] = xstrdup(filename);
n_ids++;
}
options.num_identity_files = n_ids;
memcpy(options.identity_files, identity_files, sizeof(identity_files));
memcpy(options.identity_keys, identity_keys, sizeof(identity_keys));
explicit_bzero(pwname, strlen(pwname));
free(pwname);
explicit_bzero(pwdir, strlen(pwdir));
free(pwdir);
}
static void
main_sigchld_handler(int sig)
{
int save_errno = errno;
pid_t pid;
int status;
while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
(pid < 0 && errno == EINTR))
;
signal(sig, main_sigchld_handler);
errno = save_errno;
}
|