summaryrefslogtreecommitdiffstats
path: root/crypto/openssh/clientloop.c
blob: 3946a9f9a7be6fce177d0b87152e5c97e7ce4c4f (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
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
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
/* $OpenBSD: clientloop.c,v 1.258 2014/02/02 03:44:31 djm Exp $ */
/* $FreeBSD$ */
/*
 * Author: Tatu Ylonen <ylo@cs.hut.fi>
 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
 *                    All rights reserved
 * The main loop for the interactive session (client side).
 *
 * 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 Theo de Raadt.  All rights reserved.
 *
 * 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.
 *
 *
 * SSH2 support added by Markus Friedl.
 * Copyright (c) 1999, 2000, 2001 Markus Friedl.  All rights reserved.
 *
 * 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"

#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/param.h>
#ifdef HAVE_SYS_STAT_H
# include <sys/stat.h>
#endif
#ifdef HAVE_SYS_TIME_H
# include <sys/time.h>
#endif
#include <sys/socket.h>

#include <ctype.h>
#include <errno.h>
#ifdef HAVE_PATHS_H
#include <paths.h>
#endif
#include <signal.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <termios.h>
#include <pwd.h>
#include <unistd.h>

#include "openbsd-compat/sys-queue.h"
#include "xmalloc.h"
#include "ssh.h"
#include "ssh1.h"
#include "ssh2.h"
#include "packet.h"
#include "buffer.h"
#include "compat.h"
#include "channels.h"
#include "dispatch.h"
#include "key.h"
#include "cipher.h"
#include "kex.h"
#include "log.h"
#include "readconf.h"
#include "clientloop.h"
#include "sshconnect.h"
#include "authfd.h"
#include "atomicio.h"
#include "sshpty.h"
#include "misc.h"
#include "match.h"
#include "msg.h"
#include "roaming.h"

/* import options */
extern Options options;

/* Flag indicating that stdin should be redirected from /dev/null. */
extern int stdin_null_flag;

/* Flag indicating that no shell has been requested */
extern int no_shell_flag;

/* Control socket */
extern int muxserver_sock; /* XXX use mux_client_cleanup() instead */

/*
 * 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.
 */
extern char *host;

/*
 * Flag to indicate that we have received a window change signal which has
 * not yet been processed.  This will cause a message indicating the new
 * window size to be sent to the server a little later.  This is volatile
 * because this is updated in a signal handler.
 */
static volatile sig_atomic_t received_window_change_signal = 0;
static volatile sig_atomic_t received_signal = 0;

/* Flag indicating whether the user's terminal is in non-blocking mode. */
static int in_non_blocking_mode = 0;

/* Time when backgrounded control master using ControlPersist should exit */
static time_t control_persist_exit_time = 0;

/* Common data for the client loop code. */
volatile sig_atomic_t quit_pending; /* Set non-zero to quit the loop. */
static int escape_char1;	/* Escape character. (proto1 only) */
static int escape_pending1;	/* Last character was an escape (proto1 only) */
static int last_was_cr;		/* Last character was a newline. */
static int exit_status;		/* Used to store the command exit status. */
static int stdin_eof;		/* EOF has been encountered on stderr. */
static Buffer stdin_buffer;	/* Buffer for stdin data. */
static Buffer stdout_buffer;	/* Buffer for stdout data. */
static Buffer stderr_buffer;	/* Buffer for stderr data. */
static u_int buffer_high;	/* Soft max buffer size. */
static int connection_in;	/* Connection to server (input). */
static int connection_out;	/* Connection to server (output). */
static int need_rekeying;	/* Set to non-zero if rekeying is requested. */
static int session_closed;	/* In SSH2: login session closed. */
static int x11_refuse_time;	/* If >0, refuse x11 opens after this time. */

static void client_init_dispatch(void);
int	session_ident = -1;

int	session_resumed = 0;

/* Track escape per proto2 channel */
struct escape_filter_ctx {
	int escape_pending;
	int escape_char;
};

/* Context for channel confirmation replies */
struct channel_reply_ctx {
	const char *request_type;
	int id;
	enum confirm_action action;
};

/* Global request success/failure callbacks */
struct global_confirm {
	TAILQ_ENTRY(global_confirm) entry;
	global_confirm_cb *cb;
	void *ctx;
	int ref_count;
};
TAILQ_HEAD(global_confirms, global_confirm);
static struct global_confirms global_confirms =
    TAILQ_HEAD_INITIALIZER(global_confirms);

/*XXX*/
extern Kex *xxx_kex;

void ssh_process_session2_setup(int, int, int, Buffer *);

/* Restores stdin to blocking mode. */

static void
leave_non_blocking(void)
{
	if (in_non_blocking_mode) {
		unset_nonblock(fileno(stdin));
		in_non_blocking_mode = 0;
	}
}

/* Puts stdin terminal in non-blocking mode. */

static void
enter_non_blocking(void)
{
	in_non_blocking_mode = 1;
	set_nonblock(fileno(stdin));
}

/*
 * Signal handler for the window change signal (SIGWINCH).  This just sets a
 * flag indicating that the window has changed.
 */
/*ARGSUSED */
static void
window_change_handler(int sig)
{
	received_window_change_signal = 1;
	signal(SIGWINCH, window_change_handler);
}

/*
 * Signal handler for signals that cause the program to terminate.  These
 * signals must be trapped to restore terminal modes.
 */
/*ARGSUSED */
static void
signal_handler(int sig)
{
	received_signal = sig;
	quit_pending = 1;
}

/*
 * Returns current time in seconds from Jan 1, 1970 with the maximum
 * available resolution.
 */

static double
get_current_time(void)
{
	struct timeval tv;
	gettimeofday(&tv, NULL);
	return (double) tv.tv_sec + (double) tv.tv_usec / 1000000.0;
}

/*
 * Sets control_persist_exit_time to the absolute time when the
 * backgrounded control master should exit due to expiry of the
 * ControlPersist timeout.  Sets it to 0 if we are not a backgrounded
 * control master process, or if there is no ControlPersist timeout.
 */
static void
set_control_persist_exit_time(void)
{
	if (muxserver_sock == -1 || !options.control_persist
	    || options.control_persist_timeout == 0) {
		/* not using a ControlPersist timeout */
		control_persist_exit_time = 0;
	} else if (channel_still_open()) {
		/* some client connections are still open */
		if (control_persist_exit_time > 0)
			debug2("%s: cancel scheduled exit", __func__);
		control_persist_exit_time = 0;
	} else if (control_persist_exit_time <= 0) {
		/* a client connection has recently closed */
		control_persist_exit_time = monotime() +
			(time_t)options.control_persist_timeout;
		debug2("%s: schedule exit in %d seconds", __func__,
		    options.control_persist_timeout);
	}
	/* else we are already counting down to the timeout */
}

#define SSH_X11_VALID_DISPLAY_CHARS ":/.-_"
static int
client_x11_display_valid(const char *display)
{
	size_t i, dlen;

	dlen = strlen(display);
	for (i = 0; i < dlen; i++) {
		if (!isalnum((u_char)display[i]) &&
		    strchr(SSH_X11_VALID_DISPLAY_CHARS, display[i]) == NULL) {
			debug("Invalid character '%c' in DISPLAY", display[i]);
			return 0;
		}
	}
	return 1;
}

#define SSH_X11_PROTO "MIT-MAGIC-COOKIE-1"
void
client_x11_get_proto(const char *display, const char *xauth_path,
    u_int trusted, u_int timeout, char **_proto, char **_data)
{
	char cmd[1024];
	char line[512];
	char xdisplay[512];
	static char proto[512], data[512];
	FILE *f;
	int got_data = 0, generated = 0, do_unlink = 0, i;
	char *xauthdir, *xauthfile;
	struct stat st;
	u_int now;

	xauthdir = xauthfile = NULL;
	*_proto = proto;
	*_data = data;
	proto[0] = data[0] = '\0';

	if (xauth_path == NULL ||(stat(xauth_path, &st) == -1)) {
		debug("No xauth program.");
	} else if (!client_x11_display_valid(display)) {
		logit("DISPLAY '%s' invalid, falling back to fake xauth data",
		    display);
	} else {
		if (display == NULL) {
			debug("x11_get_proto: DISPLAY not set");
			return;
		}
		/*
		 * Handle FamilyLocal case where $DISPLAY does
		 * not match an authorization entry.  For this we
		 * just try "xauth list unix:displaynum.screennum".
		 * XXX: "localhost" match to determine FamilyLocal
		 *      is not perfect.
		 */
		if (strncmp(display, "localhost:", 10) == 0) {
			snprintf(xdisplay, sizeof(xdisplay), "unix:%s",
			    display + 10);
			display = xdisplay;
		}
		if (trusted == 0) {
			xauthdir = xmalloc(MAXPATHLEN);
			xauthfile = xmalloc(MAXPATHLEN);
			mktemp_proto(xauthdir, MAXPATHLEN);
			if (mkdtemp(xauthdir) != NULL) {
				do_unlink = 1;
				snprintf(xauthfile, MAXPATHLEN, "%s/xauthfile",
				    xauthdir);
				snprintf(cmd, sizeof(cmd),
				    "%s -f %s generate %s " SSH_X11_PROTO
				    " untrusted timeout %u 2>" _PATH_DEVNULL,
				    xauth_path, xauthfile, display, timeout);
				debug2("x11_get_proto: %s", cmd);
				if (system(cmd) == 0)
					generated = 1;
				if (x11_refuse_time == 0) {
					now = monotime() + 1;
					if (UINT_MAX - timeout < now)
						x11_refuse_time = UINT_MAX;
					else
						x11_refuse_time = now + timeout;
				}
			}
		}

		/*
		 * When in untrusted mode, we read the cookie only if it was
		 * successfully generated as an untrusted one in the step
		 * above.
		 */
		if (trusted || generated) {
			snprintf(cmd, sizeof(cmd),
			    "%s %s%s list %s 2>" _PATH_DEVNULL,
			    xauth_path,
			    generated ? "-f " : "" ,
			    generated ? xauthfile : "",
			    display);
			debug2("x11_get_proto: %s", cmd);
			f = popen(cmd, "r");
			if (f && fgets(line, sizeof(line), f) &&
			    sscanf(line, "%*s %511s %511s", proto, data) == 2)
				got_data = 1;
			if (f)
				pclose(f);
		} else
			error("Warning: untrusted X11 forwarding setup failed: "
			    "xauth key data not generated");
	}

	if (do_unlink) {
		unlink(xauthfile);
		rmdir(xauthdir);
	}
	free(xauthdir);
	free(xauthfile);

	/*
	 * If we didn't get authentication data, just make up some
	 * data.  The forwarding code will check the validity of the
	 * response anyway, and substitute this data.  The X11
	 * server, however, will ignore this fake data and use
	 * whatever authentication mechanisms it was using otherwise
	 * for the local connection.
	 */
	if (!got_data) {
		u_int32_t rnd = 0;

		logit("Warning: No xauth data; "
		    "using fake authentication data for X11 forwarding.");
		strlcpy(proto, SSH_X11_PROTO, sizeof proto);
		for (i = 0; i < 16; i++) {
			if (i % 4 == 0)
				rnd = arc4random();
			snprintf(data + 2 * i, sizeof data - 2 * i, "%02x",
			    rnd & 0xff);
			rnd >>= 8;
		}
	}
}

/*
 * This is called when the interactive is entered.  This checks if there is
 * an EOF coming on stdin.  We must check this explicitly, as select() does
 * not appear to wake up when redirecting from /dev/null.
 */

static void
client_check_initial_eof_on_stdin(void)
{
	int len;
	char buf[1];

	/*
	 * If standard input is to be "redirected from /dev/null", we simply
	 * mark that we have seen an EOF and send an EOF message to the
	 * server. Otherwise, we try to read a single character; it appears
	 * that for some files, such /dev/null, select() never wakes up for
	 * read for this descriptor, which means that we never get EOF.  This
	 * way we will get the EOF if stdin comes from /dev/null or similar.
	 */
	if (stdin_null_flag) {
		/* Fake EOF on stdin. */
		debug("Sending eof.");
		stdin_eof = 1;
		packet_start(SSH_CMSG_EOF);
		packet_send();
	} else {
		enter_non_blocking();

		/* Check for immediate EOF on stdin. */
		len = read(fileno(stdin), buf, 1);
		if (len == 0) {
			/*
			 * EOF.  Record that we have seen it and send
			 * EOF to server.
			 */
			debug("Sending eof.");
			stdin_eof = 1;
			packet_start(SSH_CMSG_EOF);
			packet_send();
		} else if (len > 0) {
			/*
			 * Got data.  We must store the data in the buffer,
			 * and also process it as an escape character if
			 * appropriate.
			 */
			if ((u_char) buf[0] == escape_char1)
				escape_pending1 = 1;
			else
				buffer_append(&stdin_buffer, buf, 1);
		}
		leave_non_blocking();
	}
}


/*
 * Make packets from buffered stdin data, and buffer them for sending to the
 * connection.
 */

static void
client_make_packets_from_stdin_data(void)
{
	u_int len;

	/* Send buffered stdin data to the server. */
	while (buffer_len(&stdin_buffer) > 0 &&
	    packet_not_very_much_data_to_write()) {
		len = buffer_len(&stdin_buffer);
		/* Keep the packets at reasonable size. */
		if (len > packet_get_maxsize())
			len = packet_get_maxsize();
		packet_start(SSH_CMSG_STDIN_DATA);
		packet_put_string(buffer_ptr(&stdin_buffer), len);
		packet_send();
		buffer_consume(&stdin_buffer, len);
		/* If we have a pending EOF, send it now. */
		if (stdin_eof && buffer_len(&stdin_buffer) == 0) {
			packet_start(SSH_CMSG_EOF);
			packet_send();
		}
	}
}

/*
 * Checks if the client window has changed, and sends a packet about it to
 * the server if so.  The actual change is detected elsewhere (by a software
 * interrupt on Unix); this just checks the flag and sends a message if
 * appropriate.
 */

static void
client_check_window_change(void)
{
	struct winsize ws;

	if (! received_window_change_signal)
		return;
	/** XXX race */
	received_window_change_signal = 0;

	debug2("client_check_window_change: changed");

	if (compat20) {
		channel_send_window_changes();
	} else {
		if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
			return;
		packet_start(SSH_CMSG_WINDOW_SIZE);
		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);
		packet_send();
	}
}

static void
client_global_request_reply(int type, u_int32_t seq, void *ctxt)
{
	struct global_confirm *gc;

	if ((gc = TAILQ_FIRST(&global_confirms)) == NULL)
		return;
	if (gc->cb != NULL)
		gc->cb(type, seq, gc->ctx);
	if (--gc->ref_count <= 0) {
		TAILQ_REMOVE(&global_confirms, gc, entry);
		explicit_bzero(gc, sizeof(*gc));
		free(gc);
	}

	packet_set_alive_timeouts(0);
}

static void
server_alive_check(void)
{
	if (packet_inc_alive_timeouts() > options.server_alive_count_max) {
		logit("Timeout, server %s not responding.", host);
		cleanup_exit(255);
	}
	packet_start(SSH2_MSG_GLOBAL_REQUEST);
	packet_put_cstring("keepalive@openssh.com");
	packet_put_char(1);     /* boolean: want reply */
	packet_send();
	/* Insert an empty placeholder to maintain ordering */
	client_register_global_confirm(NULL, NULL);
}

/*
 * Waits until the client can do something (some data becomes available on
 * one of the file descriptors).
 */
static void
client_wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp,
    int *maxfdp, u_int *nallocp, int rekeying)
{
	struct timeval tv, *tvp;
	int timeout_secs;
	time_t minwait_secs = 0, server_alive_time = 0, now = monotime();
	int ret;

	/* Add any selections by the channel mechanism. */
	channel_prepare_select(readsetp, writesetp, maxfdp, nallocp,
	    &minwait_secs, rekeying);

	if (!compat20) {
		/* Read from the connection, unless our buffers are full. */
		if (buffer_len(&stdout_buffer) < buffer_high &&
		    buffer_len(&stderr_buffer) < buffer_high &&
		    channel_not_very_much_buffered_data())
			FD_SET(connection_in, *readsetp);
		/*
		 * Read from stdin, unless we have seen EOF or have very much
		 * buffered data to send to the server.
		 */
		if (!stdin_eof && packet_not_very_much_data_to_write())
			FD_SET(fileno(stdin), *readsetp);

		/* Select stdout/stderr if have data in buffer. */
		if (buffer_len(&stdout_buffer) > 0)
			FD_SET(fileno(stdout), *writesetp);
		if (buffer_len(&stderr_buffer) > 0)
			FD_SET(fileno(stderr), *writesetp);
	} else {
		/* channel_prepare_select could have closed the last channel */
		if (session_closed && !channel_still_open() &&
		    !packet_have_data_to_write()) {
			/* clear mask since we did not call select() */
			memset(*readsetp, 0, *nallocp);
			memset(*writesetp, 0, *nallocp);
			return;
		} else {
			FD_SET(connection_in, *readsetp);
		}
	}

	/* Select server connection if have data to write to the server. */
	if (packet_have_data_to_write())
		FD_SET(connection_out, *writesetp);

	/*
	 * Wait for something to happen.  This will suspend the process until
	 * some selected descriptor can be read, written, or has some other
	 * event pending, or a timeout expires.
	 */

	timeout_secs = INT_MAX; /* we use INT_MAX to mean no timeout */
	if (options.server_alive_interval > 0 && compat20) {
		timeout_secs = options.server_alive_interval;
		server_alive_time = now + options.server_alive_interval;
	}
	if (options.rekey_interval > 0 && compat20 && !rekeying)
		timeout_secs = MIN(timeout_secs, packet_get_rekey_timeout());
	set_control_persist_exit_time();
	if (control_persist_exit_time > 0) {
		timeout_secs = MIN(timeout_secs,
			control_persist_exit_time - now);
		if (timeout_secs < 0)
			timeout_secs = 0;
	}
	if (minwait_secs != 0)
		timeout_secs = MIN(timeout_secs, (int)minwait_secs);
	if (timeout_secs == INT_MAX)
		tvp = NULL;
	else {
		tv.tv_sec = timeout_secs;
		tv.tv_usec = 0;
		tvp = &tv;
	}

	ret = select((*maxfdp)+1, *readsetp, *writesetp, NULL, tvp);
	if (ret < 0) {
		char buf[100];

		/*
		 * We have to clear the select masks, because we return.
		 * We have to return, because the mainloop checks for the flags
		 * set by the signal handlers.
		 */
		memset(*readsetp, 0, *nallocp);
		memset(*writesetp, 0, *nallocp);

		if (errno == EINTR)
			return;
		/* Note: we might still have data in the buffers. */
		snprintf(buf, sizeof buf, "select: %s\r\n", strerror(errno));
		buffer_append(&stderr_buffer, buf, strlen(buf));
		quit_pending = 1;
	} else if (ret == 0) {
		/*
		 * Timeout.  Could have been either keepalive or rekeying.
		 * Keepalive we check here, rekeying is checked in clientloop.
		 */
		if (server_alive_time != 0 && server_alive_time <= monotime())
			server_alive_check();
	}

}

static void
client_suspend_self(Buffer *bin, Buffer *bout, Buffer *berr)
{
	/* Flush stdout and stderr buffers. */
	if (buffer_len(bout) > 0)
		atomicio(vwrite, fileno(stdout), buffer_ptr(bout),
		    buffer_len(bout));
	if (buffer_len(berr) > 0)
		atomicio(vwrite, fileno(stderr), buffer_ptr(berr),
		    buffer_len(berr));

	leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE);

	/*
	 * Free (and clear) the buffer to reduce the amount of data that gets
	 * written to swap.
	 */
	buffer_free(bin);
	buffer_free(bout);
	buffer_free(berr);

	/* Send the suspend signal to the program itself. */
	kill(getpid(), SIGTSTP);

	/* Reset window sizes in case they have changed */
	received_window_change_signal = 1;

	/* OK, we have been continued by the user. Reinitialize buffers. */
	buffer_init(bin);
	buffer_init(bout);
	buffer_init(berr);

	enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
}

static void
client_process_net_input(fd_set *readset)
{
	int len, cont = 0;
	char buf[SSH_IOBUFSZ];

	/*
	 * Read input from the server, and add any such data to the buffer of
	 * the packet subsystem.
	 */
	if (FD_ISSET(connection_in, readset)) {
		/* Read as much as possible. */
		len = roaming_read(connection_in, buf, sizeof(buf), &cont);
		if (len == 0 && cont == 0) {
			/*
			 * Received EOF.  The remote host has closed the
			 * connection.
			 */
			snprintf(buf, sizeof buf,
			    "Connection to %.300s closed by remote host.\r\n",
			    host);
			buffer_append(&stderr_buffer, buf, strlen(buf));
			quit_pending = 1;
			return;
		}
		/*
		 * There is a kernel bug on Solaris that causes select to
		 * sometimes wake up even though there is no data available.
		 */
		if (len < 0 &&
		    (errno == EAGAIN || errno == EINTR || errno == EWOULDBLOCK))
			len = 0;

		if (len < 0) {
			/*
			 * An error has encountered.  Perhaps there is a
			 * network problem.
			 */
			snprintf(buf, sizeof buf,
			    "Read from remote host %.300s: %.100s\r\n",
			    host, strerror(errno));
			buffer_append(&stderr_buffer, buf, strlen(buf));
			quit_pending = 1;
			return;
		}
		packet_process_incoming(buf, len);
	}
}

static void
client_status_confirm(int type, Channel *c, void *ctx)
{
	struct channel_reply_ctx *cr = (struct channel_reply_ctx *)ctx;
	char errmsg[256];
	int tochan;

	/*
	 * If a TTY was explicitly requested, then a failure to allocate
	 * one is fatal.
	 */
	if (cr->action == CONFIRM_TTY &&
	    (options.request_tty == REQUEST_TTY_FORCE ||
	    options.request_tty == REQUEST_TTY_YES))
		cr->action = CONFIRM_CLOSE;

	/* XXX supress on mux _client_ quietmode */
	tochan = options.log_level >= SYSLOG_LEVEL_ERROR &&
	    c->ctl_chan != -1 && c->extended_usage == CHAN_EXTENDED_WRITE;

	if (type == SSH2_MSG_CHANNEL_SUCCESS) {
		debug2("%s request accepted on channel %d",
		    cr->request_type, c->self);
	} else if (type == SSH2_MSG_CHANNEL_FAILURE) {
		if (tochan) {
			snprintf(errmsg, sizeof(errmsg),
			    "%s request failed\r\n", cr->request_type);
		} else {
			snprintf(errmsg, sizeof(errmsg),
			    "%s request failed on channel %d",
			    cr->request_type, c->self);
		}
		/* If error occurred on primary session channel, then exit */
		if (cr->action == CONFIRM_CLOSE && c->self == session_ident)
			fatal("%s", errmsg);
		/*
		 * If error occurred on mux client, append to
		 * their stderr.
		 */
		if (tochan) {
			buffer_append(&c->extended, errmsg,
			    strlen(errmsg));
		} else
			error("%s", errmsg);
		if (cr->action == CONFIRM_TTY) {
			/*
			 * If a TTY allocation error occurred, then arrange
			 * for the correct TTY to leave raw mode.
			 */
			if (c->self == session_ident)
				leave_raw_mode(0);
			else
				mux_tty_alloc_failed(c);
		} else if (cr->action == CONFIRM_CLOSE) {
			chan_read_failed(c);
			chan_write_failed(c);
		}
	}
	free(cr);
}

static void
client_abandon_status_confirm(Channel *c, void *ctx)
{
	free(ctx);
}

void
client_expect_confirm(int id, const char *request,
    enum confirm_action action)
{
	struct channel_reply_ctx *cr = xcalloc(1, sizeof(*cr));

	cr->request_type = request;
	cr->action = action;

	channel_register_status_confirm(id, client_status_confirm,
	    client_abandon_status_confirm, cr);
}

void
client_register_global_confirm(global_confirm_cb *cb, void *ctx)
{
	struct global_confirm *gc, *last_gc;

	/* Coalesce identical callbacks */
	last_gc = TAILQ_LAST(&global_confirms, global_confirms);
	if (last_gc && last_gc->cb == cb && last_gc->ctx == ctx) {
		if (++last_gc->ref_count >= INT_MAX)
			fatal("%s: last_gc->ref_count = %d",
			    __func__, last_gc->ref_count);
		return;
	}

	gc = xcalloc(1, sizeof(*gc));
	gc->cb = cb;
	gc->ctx = ctx;
	gc->ref_count = 1;
	TAILQ_INSERT_TAIL(&global_confirms, gc, entry);
}

static void
process_cmdline(void)
{
	void (*handler)(int);
	char *s, *cmd, *cancel_host;
	int delete = 0, local = 0, remote = 0, dynamic = 0;
	int cancel_port, ok;
	Forward fwd;

	memset(&fwd, 0, sizeof(fwd));
	fwd.listen_host = fwd.connect_host = NULL;

	leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
	handler = signal(SIGINT, SIG_IGN);
	cmd = s = read_passphrase("\r\nssh> ", RP_ECHO);
	if (s == NULL)
		goto out;
	while (isspace((u_char)*s))
		s++;
	if (*s == '-')
		s++;	/* Skip cmdline '-', if any */
	if (*s == '\0')
		goto out;

	if (*s == 'h' || *s == 'H' || *s == '?') {
		logit("Commands:");
		logit("      -L[bind_address:]port:host:hostport    "
		    "Request local forward");
		logit("      -R[bind_address:]port:host:hostport    "
		    "Request remote forward");
		logit("      -D[bind_address:]port                  "
		    "Request dynamic forward");
		logit("      -KL[bind_address:]port                 "
		    "Cancel local forward");
		logit("      -KR[bind_address:]port                 "
		    "Cancel remote forward");
		logit("      -KD[bind_address:]port                 "
		    "Cancel dynamic forward");
		if (!options.permit_local_command)
			goto out;
		logit("      !args                                  "
		    "Execute local command");
		goto out;
	}

	if (*s == '!' && options.permit_local_command) {
		s++;
		ssh_local_cmd(s);
		goto out;
	}

	if (*s == 'K') {
		delete = 1;
		s++;
	}
	if (*s == 'L')
		local = 1;
	else if (*s == 'R')
		remote = 1;
	else if (*s == 'D')
		dynamic = 1;
	else {
		logit("Invalid command.");
		goto out;
	}

	if (delete && !compat20) {
		logit("Not supported for SSH protocol version 1.");
		goto out;
	}

	while (isspace((u_char)*++s))
		;

	/* XXX update list of forwards in options */
	if (delete) {
		cancel_port = 0;
		cancel_host = hpdelim(&s);	/* may be NULL */
		if (s != NULL) {
			cancel_port = a2port(s);
			cancel_host = cleanhostname(cancel_host);
		} else {
			cancel_port = a2port(cancel_host);
			cancel_host = NULL;
		}
		if (cancel_port <= 0) {
			logit("Bad forwarding close port");
			goto out;
		}
		if (remote)
			ok = channel_request_rforward_cancel(cancel_host,
			    cancel_port) == 0;
		else if (dynamic)
                	ok = channel_cancel_lport_listener(cancel_host,
			    cancel_port, 0, options.gateway_ports) > 0;
		else
                	ok = channel_cancel_lport_listener(cancel_host,
			    cancel_port, CHANNEL_CANCEL_PORT_STATIC,
			    options.gateway_ports) > 0;
		if (!ok) {
			logit("Unkown port forwarding.");
			goto out;
		}
		logit("Canceled forwarding.");
	} else {
		if (!parse_forward(&fwd, s, dynamic, remote)) {
			logit("Bad forwarding specification.");
			goto out;
		}
		if (local || dynamic) {
			if (!channel_setup_local_fwd_listener(fwd.listen_host,
			    fwd.listen_port, fwd.connect_host,
			    fwd.connect_port, options.gateway_ports)) {
				logit("Port forwarding failed.");
				goto out;
			}
		} else {
			if (channel_request_remote_forwarding(fwd.listen_host,
			    fwd.listen_port, fwd.connect_host,
			    fwd.connect_port) < 0) {
				logit("Port forwarding failed.");
				goto out;
			}
		}
		logit("Forwarding port.");
	}

out:
	signal(SIGINT, handler);
	enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
	free(cmd);
	free(fwd.listen_host);
	free(fwd.connect_host);
}

/* reasons to suppress output of an escape command in help output */
#define SUPPRESS_NEVER		0	/* never suppress, always show */
#define SUPPRESS_PROTO1		1	/* don't show in protocol 1 sessions */
#define SUPPRESS_MUXCLIENT	2	/* don't show in mux client sessions */
#define SUPPRESS_MUXMASTER	4	/* don't show in mux master sessions */
#define SUPPRESS_SYSLOG		8	/* don't show when logging to syslog */
struct escape_help_text {
	const char *cmd;
	const char *text;
	unsigned int flags;
};
static struct escape_help_text esc_txt[] = {
    {".",  "terminate session", SUPPRESS_MUXMASTER},
    {".",  "terminate connection (and any multiplexed sessions)",
	SUPPRESS_MUXCLIENT},
    {"B",  "send a BREAK to the remote system", SUPPRESS_PROTO1},
    {"C",  "open a command line", SUPPRESS_MUXCLIENT},
    {"R",  "request rekey", SUPPRESS_PROTO1},
    {"V/v",  "decrease/increase verbosity (LogLevel)", SUPPRESS_MUXCLIENT},
    {"^Z", "suspend ssh", SUPPRESS_MUXCLIENT},
    {"#",  "list forwarded connections", SUPPRESS_NEVER},
    {"&",  "background ssh (when waiting for connections to terminate)",
	SUPPRESS_MUXCLIENT},
    {"?", "this message", SUPPRESS_NEVER},
};

static void
print_escape_help(Buffer *b, int escape_char, int protocol2, int mux_client,
    int using_stderr)
{
	unsigned int i, suppress_flags;
	char string[1024];

	snprintf(string, sizeof string, "%c?\r\n"
	    "Supported escape sequences:\r\n", escape_char);
	buffer_append(b, string, strlen(string));

	suppress_flags = (protocol2 ? 0 : SUPPRESS_PROTO1) |
	    (mux_client ? SUPPRESS_MUXCLIENT : 0) |
	    (mux_client ? 0 : SUPPRESS_MUXMASTER) |
	    (using_stderr ? 0 : SUPPRESS_SYSLOG);

	for (i = 0; i < sizeof(esc_txt)/sizeof(esc_txt[0]); i++) {
		if (esc_txt[i].flags & suppress_flags)
			continue;
		snprintf(string, sizeof string, " %c%-3s - %s\r\n",
		    escape_char, esc_txt[i].cmd, esc_txt[i].text);
		buffer_append(b, string, strlen(string));
	}

	snprintf(string, sizeof string,
	    " %c%c   - send the escape character by typing it twice\r\n"
	    "(Note that escapes are only recognized immediately after "
	    "newline.)\r\n", escape_char, escape_char);
	buffer_append(b, string, strlen(string));
}

/* 
 * Process the characters one by one, call with c==NULL for proto1 case.
 */
static int
process_escapes(Channel *c, Buffer *bin, Buffer *bout, Buffer *berr,
    char *buf, int len)
{
	char string[1024];
	pid_t pid;
	int bytes = 0;
	u_int i;
	u_char ch;
	char *s;
	int *escape_pendingp, escape_char;
	struct escape_filter_ctx *efc;

	if (c == NULL) {
		escape_pendingp = &escape_pending1;
		escape_char = escape_char1;
	} else {
		if (c->filter_ctx == NULL)
			return 0;
		efc = (struct escape_filter_ctx *)c->filter_ctx;
		escape_pendingp = &efc->escape_pending;
		escape_char = efc->escape_char;
	}
	
	if (len <= 0)
		return (0);

	for (i = 0; i < (u_int)len; i++) {
		/* Get one character at a time. */
		ch = buf[i];

		if (*escape_pendingp) {
			/* We have previously seen an escape character. */
			/* Clear the flag now. */
			*escape_pendingp = 0;

			/* Process the escaped character. */
			switch (ch) {
			case '.':
				/* Terminate the connection. */
				snprintf(string, sizeof string, "%c.\r\n",
				    escape_char);
				buffer_append(berr, string, strlen(string));

				if (c && c->ctl_chan != -1) {
					chan_read_failed(c);
					chan_write_failed(c);
					if (c->detach_user)
						c->detach_user(c->self, NULL);
					c->type = SSH_CHANNEL_ABANDONED;
					buffer_clear(&c->input);
					chan_ibuf_empty(c);
					return 0;
				} else
					quit_pending = 1;
				return -1;

			case 'Z' - 64:
				/* XXX support this for mux clients */
				if (c && c->ctl_chan != -1) {
					char b[16];
 noescape:
					if (ch == 'Z' - 64)
						snprintf(b, sizeof b, "^Z");
					else
						snprintf(b, sizeof b, "%c", ch);
					snprintf(string, sizeof string,
					    "%c%s escape not available to "
					    "multiplexed sessions\r\n",
					    escape_char, b);
					buffer_append(berr, string,
					    strlen(string));
					continue;
				}
				/* Suspend the program. Inform the user */
				snprintf(string, sizeof string,
				    "%c^Z [suspend ssh]\r\n", escape_char);
				buffer_append(berr, string, strlen(string));

				/* Restore terminal modes and suspend. */
				client_suspend_self(bin, bout, berr);

				/* We have been continued. */
				continue;

			case 'B':
				if (compat20) {
					snprintf(string, sizeof string,
					    "%cB\r\n", escape_char);
					buffer_append(berr, string,
					    strlen(string));
					channel_request_start(c->self,
					    "break", 0);
					packet_put_int(1000);
					packet_send();
				}
				continue;

			case 'R':
				if (compat20) {
					if (datafellows & SSH_BUG_NOREKEY)
						logit("Server does not "
						    "support re-keying");
					else
						need_rekeying = 1;
				}
				continue;

			case 'V':
				/* FALLTHROUGH */
			case 'v':
				if (c && c->ctl_chan != -1)
					goto noescape;
				if (!log_is_on_stderr()) {
					snprintf(string, sizeof string,
					    "%c%c [Logging to syslog]\r\n",
					     escape_char, ch);
					buffer_append(berr, string,
					    strlen(string));
					continue;
				}
				if (ch == 'V' && options.log_level >
				    SYSLOG_LEVEL_QUIET)
					log_change_level(--options.log_level);
				if (ch == 'v' && options.log_level <
				    SYSLOG_LEVEL_DEBUG3)
					log_change_level(++options.log_level);
				snprintf(string, sizeof string,
				    "%c%c [LogLevel %s]\r\n", escape_char, ch,
				    log_level_name(options.log_level));
				buffer_append(berr, string, strlen(string));
				continue;

			case '&':
				if (c && c->ctl_chan != -1)
					goto noescape;
				/*
				 * Detach the program (continue to serve
				 * connections, but put in background and no
				 * more new connections).
				 */
				/* Restore tty modes. */
				leave_raw_mode(
				    options.request_tty == REQUEST_TTY_FORCE);

				/* Stop listening for new connections. */
				channel_stop_listening();

				snprintf(string, sizeof string,
				    "%c& [backgrounded]\n", escape_char);
				buffer_append(berr, string, strlen(string));

				/* Fork into background. */
				pid = fork();
				if (pid < 0) {
					error("fork: %.100s", strerror(errno));
					continue;
				}
				if (pid != 0) {	/* This is the parent. */
					/* The parent just exits. */
					exit(0);
				}
				/* The child continues serving connections. */
				if (compat20) {
					buffer_append(bin, "\004", 1);
					/* fake EOF on stdin */
					return -1;
				} else if (!stdin_eof) {
					/*
					 * Sending SSH_CMSG_EOF alone does not
					 * always appear to be enough.  So we
					 * try to send an EOF character first.
					 */
					packet_start(SSH_CMSG_STDIN_DATA);
					packet_put_string("\004", 1);
					packet_send();
					/* Close stdin. */
					stdin_eof = 1;
					if (buffer_len(bin) == 0) {
						packet_start(SSH_CMSG_EOF);
						packet_send();
					}
				}
				continue;

			case '?':
				print_escape_help(berr, escape_char, compat20,
				    (c && c->ctl_chan != -1),
				    log_is_on_stderr());
				continue;

			case '#':
				snprintf(string, sizeof string, "%c#\r\n",
				    escape_char);
				buffer_append(berr, string, strlen(string));
				s = channel_open_message();
				buffer_append(berr, s, strlen(s));
				free(s);
				continue;

			case 'C':
				if (c && c->ctl_chan != -1)
					goto noescape;
				process_cmdline();
				continue;

			default:
				if (ch != escape_char) {
					buffer_put_char(bin, escape_char);
					bytes++;
				}
				/* Escaped characters fall through here */
				break;
			}
		} else {
			/*
			 * The previous character was not an escape char.
			 * Check if this is an escape.
			 */
			if (last_was_cr && ch == escape_char) {
				/*
				 * It is. Set the flag and continue to
				 * next character.
				 */
				*escape_pendingp = 1;
				continue;
			}
		}

		/*
		 * Normal character.  Record whether it was a newline,
		 * and append it to the buffer.
		 */
		last_was_cr = (ch == '\r' || ch == '\n');
		buffer_put_char(bin, ch);
		bytes++;
	}
	return bytes;
}

static void
client_process_input(fd_set *readset)
{
	int len;
	char buf[SSH_IOBUFSZ];

	/* Read input from stdin. */
	if (FD_ISSET(fileno(stdin), readset)) {
		/* Read as much as possible. */
		len = read(fileno(stdin), buf, sizeof(buf));
		if (len < 0 &&
		    (errno == EAGAIN || errno == EINTR || errno == EWOULDBLOCK))
			return;		/* we'll try again later */
		if (len <= 0) {
			/*
			 * Received EOF or error.  They are treated
			 * similarly, except that an error message is printed
			 * if it was an error condition.
			 */
			if (len < 0) {
				snprintf(buf, sizeof buf, "read: %.100s\r\n",
				    strerror(errno));
				buffer_append(&stderr_buffer, buf, strlen(buf));
			}
			/* Mark that we have seen EOF. */
			stdin_eof = 1;
			/*
			 * Send an EOF message to the server unless there is
			 * data in the buffer.  If there is data in the
			 * buffer, no message will be sent now.  Code
			 * elsewhere will send the EOF when the buffer
			 * becomes empty if stdin_eof is set.
			 */
			if (buffer_len(&stdin_buffer) == 0) {
				packet_start(SSH_CMSG_EOF);
				packet_send();
			}
		} else if (escape_char1 == SSH_ESCAPECHAR_NONE) {
			/*
			 * Normal successful read, and no escape character.
			 * Just append the data to buffer.
			 */
			buffer_append(&stdin_buffer, buf, len);
		} else {
			/*
			 * Normal, successful read.  But we have an escape
			 * character and have to process the characters one
			 * by one.
			 */
			if (process_escapes(NULL, &stdin_buffer,
			    &stdout_buffer, &stderr_buffer, buf, len) == -1)
				return;
		}
	}
}

static void
client_process_output(fd_set *writeset)
{
	int len;
	char buf[100];

	/* Write buffered output to stdout. */
	if (FD_ISSET(fileno(stdout), writeset)) {
		/* Write as much data as possible. */
		len = write(fileno(stdout), buffer_ptr(&stdout_buffer),
		    buffer_len(&stdout_buffer));
		if (len <= 0) {
			if (errno == EINTR || errno == EAGAIN ||
			    errno == EWOULDBLOCK)
				len = 0;
			else {
				/*
				 * An error or EOF was encountered.  Put an
				 * error message to stderr buffer.
				 */
				snprintf(buf, sizeof buf,
				    "write stdout: %.50s\r\n", strerror(errno));
				buffer_append(&stderr_buffer, buf, strlen(buf));
				quit_pending = 1;
				return;
			}
		}
		/* Consume printed data from the buffer. */
		buffer_consume(&stdout_buffer, len);
	}
	/* Write buffered output to stderr. */
	if (FD_ISSET(fileno(stderr), writeset)) {
		/* Write as much data as possible. */
		len = write(fileno(stderr), buffer_ptr(&stderr_buffer),
		    buffer_len(&stderr_buffer));
		if (len <= 0) {
			if (errno == EINTR || errno == EAGAIN ||
			    errno == EWOULDBLOCK)
				len = 0;
			else {
				/*
				 * EOF or error, but can't even print
				 * error message.
				 */
				quit_pending = 1;
				return;
			}
		}
		/* Consume printed characters from the buffer. */
		buffer_consume(&stderr_buffer, len);
	}
}

/*
 * Get packets from the connection input buffer, and process them as long as
 * there are packets available.
 *
 * Any unknown packets received during the actual
 * session cause the session to terminate.  This is
 * intended to make debugging easier since no
 * confirmations are sent.  Any compatible protocol
 * extensions must be negotiated during the
 * preparatory phase.
 */

static void
client_process_buffered_input_packets(void)
{
	dispatch_run(DISPATCH_NONBLOCK, &quit_pending,
	    compat20 ? xxx_kex : NULL);
}

/* scan buf[] for '~' before sending data to the peer */

/* Helper: allocate a new escape_filter_ctx and fill in its escape char */
void *
client_new_escape_filter_ctx(int escape_char)
{
	struct escape_filter_ctx *ret;

	ret = xcalloc(1, sizeof(*ret));
	ret->escape_pending = 0;
	ret->escape_char = escape_char;
	return (void *)ret;
}

/* Free the escape filter context on channel free */
void
client_filter_cleanup(int cid, void *ctx)
{
	free(ctx);
}

int
client_simple_escape_filter(Channel *c, char *buf, int len)
{
	if (c->extended_usage != CHAN_EXTENDED_WRITE)
		return 0;

	return process_escapes(c, &c->input, &c->output, &c->extended,
	    buf, len);
}

static void
client_channel_closed(int id, void *arg)
{
	channel_cancel_cleanup(id);
	session_closed = 1;
	leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
}

/*
 * Implements the interactive session with the server.  This is called after
 * the user has been authenticated, and a command has been started on the
 * remote host.  If escape_char != SSH_ESCAPECHAR_NONE, it is the character
 * used as an escape character for terminating or suspending the session.
 */

int
client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id)
{
	fd_set *readset = NULL, *writeset = NULL;
	double start_time, total_time;
	int max_fd = 0, max_fd2 = 0, len, rekeying = 0;
	u_int64_t ibytes, obytes;
	u_int nalloc = 0;
	char buf[100];

	debug("Entering interactive session.");

	start_time = get_current_time();

	/* Initialize variables. */
	escape_pending1 = 0;
	last_was_cr = 1;
	exit_status = -1;
	stdin_eof = 0;
	buffer_high = 64 * 1024;
	connection_in = packet_get_connection_in();
	connection_out = packet_get_connection_out();
	max_fd = MAX(connection_in, connection_out);

	if (!compat20) {
		/* enable nonblocking unless tty */
		if (!isatty(fileno(stdin)))
			set_nonblock(fileno(stdin));
		if (!isatty(fileno(stdout)))
			set_nonblock(fileno(stdout));
		if (!isatty(fileno(stderr)))
			set_nonblock(fileno(stderr));
		max_fd = MAX(max_fd, fileno(stdin));
		max_fd = MAX(max_fd, fileno(stdout));
		max_fd = MAX(max_fd, fileno(stderr));
	}
	quit_pending = 0;
	escape_char1 = escape_char_arg;

	/* Initialize buffers. */
	buffer_init(&stdin_buffer);
	buffer_init(&stdout_buffer);
	buffer_init(&stderr_buffer);

	client_init_dispatch();

	/*
	 * Set signal handlers, (e.g. to restore non-blocking mode)
	 * but don't overwrite SIG_IGN, matches behaviour from rsh(1)
	 */
	if (signal(SIGHUP, SIG_IGN) != SIG_IGN)
		signal(SIGHUP, signal_handler);
	if (signal(SIGINT, SIG_IGN) != SIG_IGN)
		signal(SIGINT, signal_handler);
	if (signal(SIGQUIT, SIG_IGN) != SIG_IGN)
		signal(SIGQUIT, signal_handler);
	if (signal(SIGTERM, SIG_IGN) != SIG_IGN)
		signal(SIGTERM, signal_handler);
	signal(SIGWINCH, window_change_handler);

	if (have_pty)
		enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE);

	if (compat20) {
		session_ident = ssh2_chan_id;
		if (session_ident != -1) {
			if (escape_char_arg != SSH_ESCAPECHAR_NONE) {
				channel_register_filter(session_ident,
				    client_simple_escape_filter, NULL,
				    client_filter_cleanup,
				    client_new_escape_filter_ctx(
				    escape_char_arg));
			}
			channel_register_cleanup(session_ident,
			    client_channel_closed, 0);
		}
	} else {
		/* Check if we should immediately send eof on stdin. */
		client_check_initial_eof_on_stdin();
	}

	/* Main loop of the client for the interactive session mode. */
	while (!quit_pending) {

		/* Process buffered packets sent by the server. */
		client_process_buffered_input_packets();

		if (compat20 && session_closed && !channel_still_open())
			break;

		rekeying = (xxx_kex != NULL && !xxx_kex->done);

		if (rekeying) {
			debug("rekeying in progress");
		} else {
			/*
			 * Make packets of buffered stdin data, and buffer
			 * them for sending to the server.
			 */
			if (!compat20)
				client_make_packets_from_stdin_data();

			/*
			 * Make packets from buffered channel data, and
			 * enqueue them for sending to the server.
			 */
			if (packet_not_very_much_data_to_write())
				channel_output_poll();

			/*
			 * Check if the window size has changed, and buffer a
			 * message about it to the server if so.
			 */
			client_check_window_change();

			if (quit_pending)
				break;
		}
		/*
		 * Wait until we have something to do (something becomes
		 * available on one of the descriptors).
		 */
		max_fd2 = max_fd;
		client_wait_until_can_do_something(&readset, &writeset,
		    &max_fd2, &nalloc, rekeying);

		if (quit_pending)
			break;

		/* Do channel operations unless rekeying in progress. */
		if (!rekeying) {
			channel_after_select(readset, writeset);
			if (need_rekeying || packet_need_rekeying()) {
				debug("need rekeying");
				xxx_kex->done = 0;
				kex_send_kexinit(xxx_kex);
				need_rekeying = 0;
			}
		}

		/* Buffer input from the connection.  */
		client_process_net_input(readset);

		if (quit_pending)
			break;

		if (!compat20) {
			/* Buffer data from stdin */
			client_process_input(readset);
			/*
			 * Process output to stdout and stderr.  Output to
			 * the connection is processed elsewhere (above).
			 */
			client_process_output(writeset);
		}

		if (session_resumed) {
			connection_in = packet_get_connection_in();
			connection_out = packet_get_connection_out();
			max_fd = MAX(max_fd, connection_out);
			max_fd = MAX(max_fd, connection_in);
			session_resumed = 0;
		}

		/*
		 * Send as much buffered packet data as possible to the
		 * sender.
		 */
		if (FD_ISSET(connection_out, writeset))
			packet_write_poll();

		/*
		 * If we are a backgrounded control master, and the
		 * timeout has expired without any active client
		 * connections, then quit.
		 */
		if (control_persist_exit_time > 0) {
			if (monotime() >= control_persist_exit_time) {
				debug("ControlPersist timeout expired");
				break;
			}
		}
	}
	free(readset);
	free(writeset);

	/* Terminate the session. */

	/* Stop watching for window change. */
	signal(SIGWINCH, SIG_DFL);

	if (compat20) {
		packet_start(SSH2_MSG_DISCONNECT);
		packet_put_int(SSH2_DISCONNECT_BY_APPLICATION);
		packet_put_cstring("disconnected by user");
		packet_put_cstring(""); /* language tag */
		packet_send();
		packet_write_wait();
	}

	channel_free_all();

	if (have_pty)
		leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE);

	/* restore blocking io */
	if (!isatty(fileno(stdin)))
		unset_nonblock(fileno(stdin));
	if (!isatty(fileno(stdout)))
		unset_nonblock(fileno(stdout));
	if (!isatty(fileno(stderr)))
		unset_nonblock(fileno(stderr));

	/*
	 * If there was no shell or command requested, there will be no remote
	 * exit status to be returned.  In that case, clear error code if the
	 * connection was deliberately terminated at this end.
	 */
	if (no_shell_flag && received_signal == SIGTERM) {
		received_signal = 0;
		exit_status = 0;
	}

	if (received_signal)
		fatal("Killed by signal %d.", (int) received_signal);

	/*
	 * In interactive mode (with pseudo tty) display a message indicating
	 * that the connection has been closed.
	 */
	if (have_pty && options.log_level != SYSLOG_LEVEL_QUIET) {
		snprintf(buf, sizeof buf,
		    "Connection to %.64s closed.\r\n", host);
		buffer_append(&stderr_buffer, buf, strlen(buf));
	}

	/* Output any buffered data for stdout. */
	if (buffer_len(&stdout_buffer) > 0) {
		len = atomicio(vwrite, fileno(stdout),
		    buffer_ptr(&stdout_buffer), buffer_len(&stdout_buffer));
		if (len < 0 || (u_int)len != buffer_len(&stdout_buffer))
			error("Write failed flushing stdout buffer.");
		else
			buffer_consume(&stdout_buffer, len);
	}

	/* Output any buffered data for stderr. */
	if (buffer_len(&stderr_buffer) > 0) {
		len = atomicio(vwrite, fileno(stderr),
		    buffer_ptr(&stderr_buffer), buffer_len(&stderr_buffer));
		if (len < 0 || (u_int)len != buffer_len(&stderr_buffer))
			error("Write failed flushing stderr buffer.");
		else
			buffer_consume(&stderr_buffer, len);
	}

	/* Clear and free any buffers. */
	memset(buf, 0, sizeof(buf));
	buffer_free(&stdin_buffer);
	buffer_free(&stdout_buffer);
	buffer_free(&stderr_buffer);

	/* Report bytes transferred, and transfer rates. */
	total_time = get_current_time() - start_time;
	packet_get_state(MODE_IN, NULL, NULL, NULL, &ibytes);
	packet_get_state(MODE_OUT, NULL, NULL, NULL, &obytes);
	verbose("Transferred: sent %llu, received %llu bytes, in %.1f seconds",
	    (unsigned long long)obytes, (unsigned long long)ibytes, total_time);
	if (total_time > 0)
		verbose("Bytes per second: sent %.1f, received %.1f",
		    obytes / total_time, ibytes / total_time);
	/* Return the exit status of the program. */
	debug("Exit status %d", exit_status);
	return exit_status;
}

/*********/

static void
client_input_stdout_data(int type, u_int32_t seq, void *ctxt)
{
	u_int data_len;
	char *data = packet_get_string(&data_len);
	packet_check_eom();
	buffer_append(&stdout_buffer, data, data_len);
	explicit_bzero(data, data_len);
	free(data);
}
static void
client_input_stderr_data(int type, u_int32_t seq, void *ctxt)
{
	u_int data_len;
	char *data = packet_get_string(&data_len);
	packet_check_eom();
	buffer_append(&stderr_buffer, data, data_len);
	explicit_bzero(data, data_len);
	free(data);
}
static void
client_input_exit_status(int type, u_int32_t seq, void *ctxt)
{
	exit_status = packet_get_int();
	packet_check_eom();
	/* Acknowledge the exit. */
	packet_start(SSH_CMSG_EXIT_CONFIRMATION);
	packet_send();
	/*
	 * Must wait for packet to be sent since we are
	 * exiting the loop.
	 */
	packet_write_wait();
	/* Flag that we want to exit. */
	quit_pending = 1;
}
static void
client_input_agent_open(int type, u_int32_t seq, void *ctxt)
{
	Channel *c = NULL;
	int remote_id, sock;

	/* Read the remote channel number from the message. */
	remote_id = packet_get_int();
	packet_check_eom();

	/*
	 * Get a connection to the local authentication agent (this may again
	 * get forwarded).
	 */
	sock = ssh_get_authentication_socket();

	/*
	 * If we could not connect the agent, send an error message back to
	 * the server. This should never happen unless the agent dies,
	 * because authentication forwarding is only enabled if we have an
	 * agent.
	 */
	if (sock >= 0) {
		c = channel_new("", SSH_CHANNEL_OPEN, sock, sock,
		    -1, 0, 0, 0, "authentication agent connection", 1);
		c->remote_id = remote_id;
		c->force_drain = 1;
	}
	if (c == NULL) {
		packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
		packet_put_int(remote_id);
	} else {
		/* Send a confirmation to the remote host. */
		debug("Forwarding authentication connection.");
		packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
		packet_put_int(remote_id);
		packet_put_int(c->self);
	}
	packet_send();
}

static Channel *
client_request_forwarded_tcpip(const char *request_type, int rchan)
{
	Channel *c = NULL;
	char *listen_address, *originator_address;
	u_short listen_port, originator_port;

	/* Get rest of the packet */
	listen_address = packet_get_string(NULL);
	listen_port = packet_get_int();
	originator_address = packet_get_string(NULL);
	originator_port = packet_get_int();
	packet_check_eom();

	debug("client_request_forwarded_tcpip: listen %s port %d, "
	    "originator %s port %d", listen_address, listen_port,
	    originator_address, originator_port);

	c = channel_connect_by_listen_address(listen_port,
	    "forwarded-tcpip", originator_address);

	free(originator_address);
	free(listen_address);
	return c;
}

static Channel *
client_request_x11(const char *request_type, int rchan)
{
	Channel *c = NULL;
	char *originator;
	u_short originator_port;
	int sock;

	if (!options.forward_x11) {
		error("Warning: ssh server tried X11 forwarding.");
		error("Warning: this is probably a break-in attempt by a "
		    "malicious server.");
		return NULL;
	}
	if (x11_refuse_time != 0 && monotime() >= x11_refuse_time) {
		verbose("Rejected X11 connection after ForwardX11Timeout "
		    "expired");
		return NULL;
	}
	originator = packet_get_string(NULL);
	if (datafellows & SSH_BUG_X11FWD) {
		debug2("buggy server: x11 request w/o originator_port");
		originator_port = 0;
	} else {
		originator_port = packet_get_int();
	}
	packet_check_eom();
	/* XXX check permission */
	debug("client_request_x11: request from %s %d", originator,
	    originator_port);
	free(originator);
	sock = x11_connect_display();
	if (sock < 0)
		return NULL;
	if (options.hpn_disabled)
		c = channel_new("x11", SSH_CHANNEL_X11_OPEN, sock, sock, -1,
		    CHAN_TCP_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
		    0, "x11", 1);
	else
		c = channel_new("x11", SSH_CHANNEL_X11_OPEN, sock, sock, -1,
		    options.hpn_buffer_size, CHAN_X11_PACKET_DEFAULT,
		    0, "x11", 1);
	c->force_drain = 1;
	return c;
}

static Channel *
client_request_agent(const char *request_type, int rchan)
{
	Channel *c = NULL;
	int sock;

	if (!options.forward_agent) {
		error("Warning: ssh server tried agent forwarding.");
		error("Warning: this is probably a break-in attempt by a "
		    "malicious server.");
		return NULL;
	}
	sock = ssh_get_authentication_socket();
	if (sock < 0)
		return NULL;
	if (options.hpn_disabled)
		c = channel_new("authentication agent connection",
		    SSH_CHANNEL_OPEN, sock, sock, -1,
		    CHAN_X11_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0,
		    "authentication agent connection", 1);
	else
		c = channel_new("authentication agent connection",
		    SSH_CHANNEL_OPEN, sock, sock, -1,
		    options.hpn_buffer_size, options.hpn_buffer_size, 0,
		    "authentication agent connection", 1);
	c->force_drain = 1;
	return c;
}

int
client_request_tun_fwd(int tun_mode, int local_tun, int remote_tun)
{
	Channel *c;
	int fd;

	if (tun_mode == SSH_TUNMODE_NO)
		return 0;

	if (!compat20) {
		error("Tunnel forwarding is not supported for protocol 1");
		return -1;
	}

	debug("Requesting tun unit %d in mode %d", local_tun, tun_mode);

	/* Open local tunnel device */
	if ((fd = tun_open(local_tun, tun_mode)) == -1) {
		error("Tunnel device open failed.");
		return -1;
	}

	if (options.hpn_disabled)
		c = channel_new("tun", SSH_CHANNEL_OPENING, fd, fd, -1,
		    CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
		    0, "tun", 1);
	else
		c = channel_new("tun", SSH_CHANNEL_OPENING, fd, fd, -1,
		    options.hpn_buffer_size, CHAN_TCP_PACKET_DEFAULT,
		    0, "tun", 1);
	c->datagram = 1;

#if defined(SSH_TUN_FILTER)
	if (options.tun_open == SSH_TUNMODE_POINTOPOINT)
		channel_register_filter(c->self, sys_tun_infilter,
		    sys_tun_outfilter, NULL, NULL);
#endif

	packet_start(SSH2_MSG_CHANNEL_OPEN);
	packet_put_cstring("tun@openssh.com");
	packet_put_int(c->self);
	packet_put_int(c->local_window_max);
	packet_put_int(c->local_maxpacket);
	packet_put_int(tun_mode);
	packet_put_int(remote_tun);
	packet_send();

	return 0;
}

/* XXXX move to generic input handler */
static void
client_input_channel_open(int type, u_int32_t seq, void *ctxt)
{
	Channel *c = NULL;
	char *ctype;
	int rchan;
	u_int rmaxpack, rwindow, len;

	ctype = packet_get_string(&len);
	rchan = packet_get_int();
	rwindow = packet_get_int();
	rmaxpack = packet_get_int();

	debug("client_input_channel_open: ctype %s rchan %d win %d max %d",
	    ctype, rchan, rwindow, rmaxpack);

	if (strcmp(ctype, "forwarded-tcpip") == 0) {
		c = client_request_forwarded_tcpip(ctype, rchan);
	} else if (strcmp(ctype, "x11") == 0) {
		c = client_request_x11(ctype, rchan);
	} else if (strcmp(ctype, "auth-agent@openssh.com") == 0) {
		c = client_request_agent(ctype, rchan);
	}
/* XXX duplicate : */
	if (c != NULL) {
		debug("confirm %s", ctype);
		c->remote_id = rchan;
		c->remote_window = rwindow;
		c->remote_maxpacket = rmaxpack;
		if (c->type != SSH_CHANNEL_CONNECTING) {
			packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
			packet_put_int(c->remote_id);
			packet_put_int(c->self);
			packet_put_int(c->local_window);
			packet_put_int(c->local_maxpacket);
			packet_send();
		}
	} else {
		debug("failure %s", ctype);
		packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
		packet_put_int(rchan);
		packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED);
		if (!(datafellows & SSH_BUG_OPENFAILURE)) {
			packet_put_cstring("open failed");
			packet_put_cstring("");
		}
		packet_send();
	}
	free(ctype);
}
static void
client_input_channel_req(int type, u_int32_t seq, void *ctxt)
{
	Channel *c = NULL;
	int exitval, id, reply, success = 0;
	char *rtype;

	id = packet_get_int();
	rtype = packet_get_string(NULL);
	reply = packet_get_char();

	debug("client_input_channel_req: channel %d rtype %s reply %d",
	    id, rtype, reply);

	if (id == -1) {
		error("client_input_channel_req: request for channel -1");
	} else if ((c = channel_lookup(id)) == NULL) {
		error("client_input_channel_req: channel %d: "
		    "unknown channel", id);
	} else if (strcmp(rtype, "eow@openssh.com") == 0) {
		packet_check_eom();
		chan_rcvd_eow(c);
	} else if (strcmp(rtype, "exit-status") == 0) {
		exitval = packet_get_int();
		if (c->ctl_chan != -1) {
			mux_exit_message(c, exitval);
			success = 1;
		} else if (id == session_ident) {
			/* Record exit value of local session */
			success = 1;
			exit_status = exitval;
		} else {
			/* Probably for a mux channel that has already closed */
			debug("%s: no sink for exit-status on channel %d",
			    __func__, id);
		}
		packet_check_eom();
	}
	if (reply && c != NULL) {
		packet_start(success ?
		    SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE);
		packet_put_int(c->remote_id);
		packet_send();
	}
	free(rtype);
}
static void
client_input_global_request(int type, u_int32_t seq, void *ctxt)
{
	char *rtype;
	int want_reply;
	int success = 0;

	rtype = packet_get_string(NULL);
	want_reply = packet_get_char();
	debug("client_input_global_request: rtype %s want_reply %d",
	    rtype, want_reply);
	if (want_reply) {
		packet_start(success ?
		    SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE);
		packet_send();
		packet_write_wait();
	}
	free(rtype);
}

void
client_session2_setup(int id, int want_tty, int want_subsystem,
    const char *term, struct termios *tiop, int in_fd, Buffer *cmd, char **env)
{
	int len;
	Channel *c = NULL;

	debug2("%s: id %d", __func__, id);

	if ((c = channel_lookup(id)) == NULL)
		fatal("client_session2_setup: channel %d: unknown channel", id);

	packet_set_interactive(want_tty,
	    options.ip_qos_interactive, options.ip_qos_bulk);

	if (want_tty) {
		struct winsize ws;

		/* Store window size in the packet. */
		if (ioctl(in_fd, TIOCGWINSZ, &ws) < 0)
			memset(&ws, 0, sizeof(ws));

		channel_request_start(id, "pty-req", 1);
		client_expect_confirm(id, "PTY allocation", CONFIRM_TTY);
		packet_put_cstring(term != NULL ? term : "");
		packet_put_int((u_int)ws.ws_col);
		packet_put_int((u_int)ws.ws_row);
		packet_put_int((u_int)ws.ws_xpixel);
		packet_put_int((u_int)ws.ws_ypixel);
		if (tiop == NULL)
			tiop = get_saved_tio();
		tty_make_modes(-1, tiop);
		packet_send();
		/* XXX wait for reply */
		c->client_tty = 1;
	}

	/* Transfer any environment variables from client to server */
	if (options.num_send_env != 0 && env != NULL) {
		int i, j, matched;
		char *name, *val;

		debug("Sending environment.");
		for (i = 0; env[i] != NULL; i++) {
			/* Split */
			name = xstrdup(env[i]);
			if ((val = strchr(name, '=')) == NULL) {
				free(name);
				continue;
			}
			*val++ = '\0';

			matched = 0;
			for (j = 0; j < options.num_send_env; j++) {
				if (match_pattern(name, options.send_env[j])) {
					matched = 1;
					break;
				}
			}
			if (!matched) {
				debug3("Ignored env %s", name);
				free(name);
				continue;
			}

			debug("Sending env %s = %s", name, val);
			channel_request_start(id, "env", 0);
			packet_put_cstring(name);
			packet_put_cstring(val);
			packet_send();
			free(name);
		}
	}

	len = buffer_len(cmd);
	if (len > 0) {
		if (len > 900)
			len = 900;
		if (want_subsystem) {
			debug("Sending subsystem: %.*s",
			    len, (u_char*)buffer_ptr(cmd));
			channel_request_start(id, "subsystem", 1);
			client_expect_confirm(id, "subsystem", CONFIRM_CLOSE);
		} else {
			debug("Sending command: %.*s",
			    len, (u_char*)buffer_ptr(cmd));
			channel_request_start(id, "exec", 1);
			client_expect_confirm(id, "exec", CONFIRM_CLOSE);
		}
		packet_put_string(buffer_ptr(cmd), buffer_len(cmd));
		packet_send();
	} else {
		channel_request_start(id, "shell", 1);
		client_expect_confirm(id, "shell", CONFIRM_CLOSE);
		packet_send();
	}
}

static void
client_init_dispatch_20(void)
{
	dispatch_init(&dispatch_protocol_error);

	dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose);
	dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data);
	dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof);
	dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data);
	dispatch_set(SSH2_MSG_CHANNEL_OPEN, &client_input_channel_open);
	dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
	dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
	dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &client_input_channel_req);
	dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust);
	dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, &channel_input_status_confirm);
	dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &channel_input_status_confirm);
	dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &client_input_global_request);

	/* rekeying */
	dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit);

	/* global request reply messages */
	dispatch_set(SSH2_MSG_REQUEST_FAILURE, &client_global_request_reply);
	dispatch_set(SSH2_MSG_REQUEST_SUCCESS, &client_global_request_reply);
}

static void
client_init_dispatch_13(void)
{
	dispatch_init(NULL);
	dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close);
	dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation);
	dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data);
	dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
	dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
	dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open);
	dispatch_set(SSH_SMSG_EXITSTATUS, &client_input_exit_status);
	dispatch_set(SSH_SMSG_STDERR_DATA, &client_input_stderr_data);
	dispatch_set(SSH_SMSG_STDOUT_DATA, &client_input_stdout_data);

	dispatch_set(SSH_SMSG_AGENT_OPEN, options.forward_agent ?
	    &client_input_agent_open : &deny_input_open);
	dispatch_set(SSH_SMSG_X11_OPEN, options.forward_x11 ?
	    &x11_input_open : &deny_input_open);
}

static void
client_init_dispatch_15(void)
{
	client_init_dispatch_13();
	dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof);
	dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, & channel_input_oclose);
}

static void
client_init_dispatch(void)
{
	if (compat20)
		client_init_dispatch_20();
	else if (compat13)
		client_init_dispatch_13();
	else
		client_init_dispatch_15();
}

void
client_stop_mux(void)
{
	if (options.control_path != NULL && muxserver_sock != -1)
		unlink(options.control_path);
	/*
	 * If we are in persist mode, or don't have a shell, signal that we
	 * should close when all active channels are closed.
	 */
	if (options.control_persist || no_shell_flag) {
		session_closed = 1;
		setproctitle("[stopped mux]");
	}
}

/* client specific fatal cleanup */
void
cleanup_exit(int i)
{
	leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
	leave_non_blocking();
	if (options.control_path != NULL && muxserver_sock != -1)
		unlink(options.control_path);
	ssh_kill_proxy_command();
	_exit(i);
}
OpenPOWER on IntegriCloud