crypto: Revert some changes in contributed code.
[dragonfly.git] / crypto / openssh / ssh.c
1 /* $OpenBSD: ssh.c,v 1.364 2011/08/02 23:15:03 djm Exp $ */
2 /*
3  * Author: Tatu Ylonen <ylo@cs.hut.fi>
4  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5  *                    All rights reserved
6  * Ssh client program.  This program can be used to log into a remote machine.
7  * The software supports strong authentication, encryption, and forwarding
8  * of X11, TCP/IP, and authentication connections.
9  *
10  * As far as I am concerned, the code I have written for this software
11  * can be used freely for any purpose.  Any derived versions of this
12  * software must be clearly marked as such, and if the derived work is
13  * incompatible with the protocol description in the RFC file, it must be
14  * called by a name other than "ssh" or "Secure Shell".
15  *
16  * Copyright (c) 1999 Niels Provos.  All rights reserved.
17  * Copyright (c) 2000, 2001, 2002, 2003 Markus Friedl.  All rights reserved.
18  *
19  * Modified to work with SSL by Niels Provos <provos@citi.umich.edu>
20  * in Canada (German citizen).
21  *
22  * Redistribution and use in source and binary forms, with or without
23  * modification, are permitted provided that the following conditions
24  * are met:
25  * 1. Redistributions of source code must retain the above copyright
26  *    notice, this list of conditions and the following disclaimer.
27  * 2. Redistributions in binary form must reproduce the above copyright
28  *    notice, this list of conditions and the following disclaimer in the
29  *    documentation and/or other materials provided with the distribution.
30  *
31  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
32  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
33  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
34  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
35  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
36  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
37  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
38  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
39  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
40  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
41  */
42
43 #include "includes.h"
44
45 #include <sys/types.h>
46 #ifdef HAVE_SYS_STAT_H
47 # include <sys/stat.h>
48 #endif
49 #include <sys/resource.h>
50 #include <sys/ioctl.h>
51 #include <sys/param.h>
52 #include <sys/socket.h>
53 #include <sys/wait.h>
54
55 #include <ctype.h>
56 #include <errno.h>
57 #include <fcntl.h>
58 #include <netdb.h>
59 #ifdef HAVE_PATHS_H
60 #include <paths.h>
61 #endif
62 #include <pwd.h>
63 #include <signal.h>
64 #include <stdarg.h>
65 #include <stddef.h>
66 #include <stdio.h>
67 #include <stdlib.h>
68 #include <string.h>
69 #include <unistd.h>
70
71 #include <netinet/in.h>
72 #include <arpa/inet.h>
73
74 #include <openssl/evp.h>
75 #include <openssl/err.h>
76 #include "openbsd-compat/openssl-compat.h"
77 #include "openbsd-compat/sys-queue.h"
78
79 #include "xmalloc.h"
80 #include "ssh.h"
81 #include "ssh1.h"
82 #include "ssh2.h"
83 #include "canohost.h"
84 #include "compat.h"
85 #include "cipher.h"
86 #include "packet.h"
87 #include "buffer.h"
88 #include "channels.h"
89 #include "key.h"
90 #include "authfd.h"
91 #include "authfile.h"
92 #include "pathnames.h"
93 #include "dispatch.h"
94 #include "clientloop.h"
95 #include "log.h"
96 #include "readconf.h"
97 #include "sshconnect.h"
98 #include "misc.h"
99 #include "kex.h"
100 #include "mac.h"
101 #include "sshpty.h"
102 #include "match.h"
103 #include "msg.h"
104 #include "uidswap.h"
105 #include "roaming.h"
106 #include "version.h"
107
108 #ifdef ENABLE_PKCS11
109 #include "ssh-pkcs11.h"
110 #endif
111
112 extern char *__progname;
113
114 /* Saves a copy of argv for setproctitle emulation */
115 #ifndef HAVE_SETPROCTITLE
116 static char **saved_av;
117 #endif
118
119 /* Flag indicating whether debug mode is on.  May be set on the command line. */
120 int debug_flag = 0;
121
122 /* Flag indicating whether a tty should be requested */
123 int tty_flag = 0;
124
125 /* don't exec a shell */
126 int no_shell_flag = 0;
127
128 /*
129  * Flag indicating that nothing should be read from stdin.  This can be set
130  * on the command line.
131  */
132 int stdin_null_flag = 0;
133
134 /*
135  * Flag indicating that the current process should be backgrounded and
136  * a new slave launched in the foreground for ControlPersist.
137  */
138 int need_controlpersist_detach = 0;
139
140 /* Copies of flags for ControlPersist foreground slave */
141 int ostdin_null_flag, ono_shell_flag, otty_flag, orequest_tty;
142
143 /*
144  * Flag indicating that ssh should fork after authentication.  This is useful
145  * so that the passphrase can be entered manually, and then ssh goes to the
146  * background.
147  */
148 int fork_after_authentication_flag = 0;
149
150 /* forward stdio to remote host and port */
151 char *stdio_forward_host = NULL;
152 int stdio_forward_port = 0;
153
154 /*
155  * General data structure for command line options and options configurable
156  * in configuration files.  See readconf.h.
157  */
158 Options options;
159
160 /* optional user configfile */
161 char *config = NULL;
162
163 /*
164  * Name of the host we are connecting to.  This is the name given on the
165  * command line, or the HostName specified for the user-supplied name in a
166  * configuration file.
167  */
168 char *host;
169
170 /* socket address the host resolves to */
171 struct sockaddr_storage hostaddr;
172
173 /* Private host keys. */
174 Sensitive sensitive_data;
175
176 /* Original real UID. */
177 uid_t original_real_uid;
178 uid_t original_effective_uid;
179
180 /* command to be executed */
181 Buffer command;
182
183 /* Should we execute a command or invoke a subsystem? */
184 int subsystem_flag = 0;
185
186 /* # of replies received for global requests */
187 static int remote_forward_confirms_received = 0;
188
189 /* mux.c */
190 extern int muxserver_sock;
191 extern u_int muxclient_command;
192
193 /* Prints a help message to the user.  This function never returns. */
194
195 static void
196 usage(void)
197 {
198         fprintf(stderr,
199 "usage: ssh [-1246AaCfgKkMNnqsTtVvXxYy] [-b bind_address] [-c cipher_spec]\n"
200 "           [-D [bind_address:]port] [-e escape_char] [-F configfile]\n"
201 "           [-I pkcs11] [-i identity_file]\n"
202 "           [-L [bind_address:]port:host:hostport]\n"
203 "           [-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port]\n"
204 "           [-R [bind_address:]port:host:hostport] [-S ctl_path]\n"
205 "           [-W host:port] [-w local_tun[:remote_tun]]\n"
206 "           [user@]hostname [command]\n"
207         );
208         exit(255);
209 }
210
211 static int ssh_session(void);
212 static int ssh_session2(void);
213 static void load_public_identity_files(void);
214 static void main_sigchld_handler(int);
215
216 /* from muxclient.c */
217 void muxclient(const char *);
218 void muxserver_listen(void);
219
220 /* ~/ expand a list of paths. NB. assumes path[n] is heap-allocated. */
221 static void
222 tilde_expand_paths(char **paths, u_int num_paths)
223 {
224         u_int i;
225         char *cp;
226
227         for (i = 0; i < num_paths; i++) {
228                 cp = tilde_expand_filename(paths[i], original_real_uid);
229                 xfree(paths[i]);
230                 paths[i] = cp;
231         }
232 }
233
234 /*
235  * Main program for the ssh client.
236  */
237 int
238 main(int ac, char **av)
239 {
240         int i, r, opt, exit_status, use_syslog;
241         char *p, *cp, *line, *argv0, buf[MAXPATHLEN], *host_arg;
242         char thishost[NI_MAXHOST], shorthost[NI_MAXHOST], portstr[NI_MAXSERV];
243         struct stat st;
244         struct passwd *pw;
245         int dummy, timeout_ms;
246         extern int optind, optreset;
247         extern char *optarg;
248
249         struct servent *sp;
250         Forward fwd;
251
252         /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
253         sanitise_stdfd();
254
255         __progname = ssh_get_progname(av[0]);
256
257 #ifndef HAVE_SETPROCTITLE
258         /* Prepare for later setproctitle emulation */
259         /* Save argv so it isn't clobbered by setproctitle() emulation */
260         saved_av = xcalloc(ac + 1, sizeof(*saved_av));
261         for (i = 0; i < ac; i++)
262                 saved_av[i] = xstrdup(av[i]);
263         saved_av[i] = NULL;
264         compat_init_setproctitle(ac, av);
265         av = saved_av;
266 #endif
267
268         /*
269          * Discard other fds that are hanging around. These can cause problem
270          * with backgrounded ssh processes started by ControlPersist.
271          */
272         closefrom(STDERR_FILENO + 1);
273
274         /*
275          * Save the original real uid.  It will be needed later (uid-swapping
276          * may clobber the real uid).
277          */
278         original_real_uid = getuid();
279         original_effective_uid = geteuid();
280
281         /*
282          * Use uid-swapping to give up root privileges for the duration of
283          * option processing.  We will re-instantiate the rights when we are
284          * ready to create the privileged port, and will permanently drop
285          * them when the port has been created (actually, when the connection
286          * has been made, as we may need to create the port several times).
287          */
288         PRIV_END;
289
290 #ifdef HAVE_SETRLIMIT
291         /* If we are installed setuid root be careful to not drop core. */
292         if (original_real_uid != original_effective_uid) {
293                 struct rlimit rlim;
294                 rlim.rlim_cur = rlim.rlim_max = 0;
295                 if (setrlimit(RLIMIT_CORE, &rlim) < 0)
296                         fatal("setrlimit failed: %.100s", strerror(errno));
297         }
298 #endif
299         /* Get user data. */
300         pw = getpwuid(original_real_uid);
301         if (!pw) {
302                 logit("You don't exist, go away!");
303                 exit(255);
304         }
305         /* Take a copy of the returned structure. */
306         pw = pwcopy(pw);
307
308         /*
309          * Set our umask to something reasonable, as some files are created
310          * with the default umask.  This will make them world-readable but
311          * writable only by the owner, which is ok for all files for which we
312          * don't set the modes explicitly.
313          */
314         umask(022);
315
316         /*
317          * Initialize option structure to indicate that no values have been
318          * set.
319          */
320         initialize_options(&options);
321
322         /* Parse command-line arguments. */
323         host = NULL;
324         use_syslog = 0;
325         argv0 = av[0];
326
327  again:
328         while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx"
329             "ACD:F:I:KL:MNO:PR:S:TVw:W:XYy")) != -1) {
330                 switch (opt) {
331                 case '1':
332                         options.protocol = SSH_PROTO_1;
333                         break;
334                 case '2':
335                         options.protocol = SSH_PROTO_2;
336                         break;
337                 case '4':
338                         options.address_family = AF_INET;
339                         break;
340                 case '6':
341                         options.address_family = AF_INET6;
342                         break;
343                 case 'n':
344                         stdin_null_flag = 1;
345                         break;
346                 case 'f':
347                         fork_after_authentication_flag = 1;
348                         stdin_null_flag = 1;
349                         break;
350                 case 'x':
351                         options.forward_x11 = 0;
352                         break;
353                 case 'X':
354                         options.forward_x11 = 1;
355                         break;
356                 case 'y':
357                         use_syslog = 1;
358                         break;
359                 case 'Y':
360                         options.forward_x11 = 1;
361                         options.forward_x11_trusted = 1;
362                         break;
363                 case 'g':
364                         options.gateway_ports = 1;
365                         break;
366                 case 'O':
367                         if (stdio_forward_host != NULL)
368                                 fatal("Cannot specify multiplexing "
369                                     "command with -W");
370                         else if (muxclient_command != 0)
371                                 fatal("Multiplexing command already specified");
372                         if (strcmp(optarg, "check") == 0)
373                                 muxclient_command = SSHMUX_COMMAND_ALIVE_CHECK;
374                         else if (strcmp(optarg, "forward") == 0)
375                                 muxclient_command = SSHMUX_COMMAND_FORWARD;
376                         else if (strcmp(optarg, "exit") == 0)
377                                 muxclient_command = SSHMUX_COMMAND_TERMINATE;
378                         else if (strcmp(optarg, "stop") == 0)
379                                 muxclient_command = SSHMUX_COMMAND_STOP;
380                         else
381                                 fatal("Invalid multiplex command.");
382                         break;
383                 case 'P':       /* deprecated */
384                         options.use_privileged_port = 0;
385                         break;
386                 case 'a':
387                         options.forward_agent = 0;
388                         break;
389                 case 'A':
390                         options.forward_agent = 1;
391                         break;
392                 case 'k':
393                         options.gss_deleg_creds = 0;
394                         break;
395                 case 'K':
396                         options.gss_authentication = 1;
397                         options.gss_deleg_creds = 1;
398                         break;
399                 case 'i':
400                         if (stat(optarg, &st) < 0) {
401                                 fprintf(stderr, "Warning: Identity file %s "
402                                     "not accessible: %s.\n", optarg,
403                                     strerror(errno));
404                                 break;
405                         }
406                         if (options.num_identity_files >=
407                             SSH_MAX_IDENTITY_FILES)
408                                 fatal("Too many identity files specified "
409                                     "(max %d)", SSH_MAX_IDENTITY_FILES);
410                         options.identity_files[options.num_identity_files++] =
411                             xstrdup(optarg);
412                         break;
413                 case 'I':
414 #ifdef ENABLE_PKCS11
415                         options.pkcs11_provider = xstrdup(optarg);
416 #else
417                         fprintf(stderr, "no support for PKCS#11.\n");
418 #endif
419                         break;
420                 case 't':
421                         if (options.request_tty == REQUEST_TTY_YES)
422                                 options.request_tty = REQUEST_TTY_FORCE;
423                         else
424                                 options.request_tty = REQUEST_TTY_YES;
425                         break;
426                 case 'v':
427                         if (debug_flag == 0) {
428                                 debug_flag = 1;
429                                 options.log_level = SYSLOG_LEVEL_DEBUG1;
430                         } else {
431                                 if (options.log_level < SYSLOG_LEVEL_DEBUG3)
432                                         options.log_level++;
433                                 break;
434                         }
435                         /* FALLTHROUGH */
436                 case 'V':
437                         fprintf(stderr, "%s, %s\n",
438                             SSH_RELEASE, SSLeay_version(SSLEAY_VERSION));
439                         if (opt == 'V')
440                                 exit(0);
441                         break;
442                 case 'w':
443                         if (options.tun_open == -1)
444                                 options.tun_open = SSH_TUNMODE_DEFAULT;
445                         options.tun_local = a2tun(optarg, &options.tun_remote);
446                         if (options.tun_local == SSH_TUNID_ERR) {
447                                 fprintf(stderr,
448                                     "Bad tun device '%s'\n", optarg);
449                                 exit(255);
450                         }
451                         break;
452                 case 'W':
453                         if (stdio_forward_host != NULL)
454                                 fatal("stdio forward already specified");
455                         if (muxclient_command != 0)
456                                 fatal("Cannot specify stdio forward with -O");
457                         if (parse_forward(&fwd, optarg, 1, 0)) {
458                                 stdio_forward_host = fwd.listen_host;
459                                 stdio_forward_port = fwd.listen_port;
460                                 xfree(fwd.connect_host);
461                         } else {
462                                 fprintf(stderr,
463                                     "Bad stdio forwarding specification '%s'\n",
464                                     optarg);
465                                 exit(255);
466                         }
467                         options.request_tty = REQUEST_TTY_NO;
468                         no_shell_flag = 1;
469                         options.clear_forwardings = 1;
470                         options.exit_on_forward_failure = 1;
471                         break;
472                 case 'q':
473                         options.log_level = SYSLOG_LEVEL_QUIET;
474                         break;
475                 case 'e':
476                         if (optarg[0] == '^' && optarg[2] == 0 &&
477                             (u_char) optarg[1] >= 64 &&
478                             (u_char) optarg[1] < 128)
479                                 options.escape_char = (u_char) optarg[1] & 31;
480                         else if (strlen(optarg) == 1)
481                                 options.escape_char = (u_char) optarg[0];
482                         else if (strcmp(optarg, "none") == 0)
483                                 options.escape_char = SSH_ESCAPECHAR_NONE;
484                         else {
485                                 fprintf(stderr, "Bad escape character '%s'.\n",
486                                     optarg);
487                                 exit(255);
488                         }
489                         break;
490                 case 'c':
491                         if (ciphers_valid(optarg)) {
492                                 /* SSH2 only */
493                                 options.ciphers = xstrdup(optarg);
494                                 options.cipher = SSH_CIPHER_INVALID;
495                         } else {
496                                 /* SSH1 only */
497                                 options.cipher = cipher_number(optarg);
498                                 if (options.cipher == -1) {
499                                         fprintf(stderr,
500                                             "Unknown cipher type '%s'\n",
501                                             optarg);
502                                         exit(255);
503                                 }
504                                 if (options.cipher == SSH_CIPHER_3DES)
505                                         options.ciphers = "3des-cbc";
506                                 else if (options.cipher == SSH_CIPHER_BLOWFISH)
507                                         options.ciphers = "blowfish-cbc";
508                                 else
509                                         options.ciphers = (char *)-1;
510                         }
511                         break;
512                 case 'm':
513                         if (mac_valid(optarg))
514                                 options.macs = xstrdup(optarg);
515                         else {
516                                 fprintf(stderr, "Unknown mac type '%s'\n",
517                                     optarg);
518                                 exit(255);
519                         }
520                         break;
521                 case 'M':
522                         if (options.control_master == SSHCTL_MASTER_YES)
523                                 options.control_master = SSHCTL_MASTER_ASK;
524                         else
525                                 options.control_master = SSHCTL_MASTER_YES;
526                         break;
527                 case 'p':
528                         options.port = a2port(optarg);
529                         if (options.port <= 0) {
530                                 fprintf(stderr, "Bad port '%s'\n", optarg);
531                                 exit(255);
532                         }
533                         break;
534                 case 'l':
535                         options.user = optarg;
536                         break;
537
538                 case 'L':
539                         if (parse_forward(&fwd, optarg, 0, 0))
540                                 add_local_forward(&options, &fwd);
541                         else {
542                                 fprintf(stderr,
543                                     "Bad local forwarding specification '%s'\n",
544                                     optarg);
545                                 exit(255);
546                         }
547                         break;
548
549                 case 'R':
550                         if (parse_forward(&fwd, optarg, 0, 1)) {
551                                 add_remote_forward(&options, &fwd);
552                         } else {
553                                 fprintf(stderr,
554                                     "Bad remote forwarding specification "
555                                     "'%s'\n", optarg);
556                                 exit(255);
557                         }
558                         break;
559
560                 case 'D':
561                         if (parse_forward(&fwd, optarg, 1, 0)) {
562                                 add_local_forward(&options, &fwd);
563                         } else {
564                                 fprintf(stderr,
565                                     "Bad dynamic forwarding specification "
566                                     "'%s'\n", optarg);
567                                 exit(255);
568                         }
569                         break;
570
571                 case 'C':
572                         options.compression = 1;
573                         break;
574                 case 'N':
575                         no_shell_flag = 1;
576                         options.request_tty = REQUEST_TTY_NO;
577                         break;
578                 case 'T':
579                         options.request_tty = REQUEST_TTY_NO;
580                         /* ensure that the user doesn't try to backdoor a */
581                         /* null cipher switch on an interactive session */
582                         /* so explicitly disable it no matter what */
583                         options.none_switch=0;
584                         break;
585                 case 'o':
586                         dummy = 1;
587                         line = xstrdup(optarg);
588                         if (process_config_line(&options, host ? host : "",
589                             line, "command-line", 0, &dummy) != 0)
590                                 exit(255);
591                         xfree(line);
592                         break;
593                 case 's':
594                         subsystem_flag = 1;
595                         break;
596                 case 'S':
597                         if (options.control_path != NULL)
598                                 free(options.control_path);
599                         options.control_path = xstrdup(optarg);
600                         break;
601                 case 'b':
602                         options.bind_address = optarg;
603                         break;
604                 case 'F':
605                         config = optarg;
606                         break;
607                 default:
608                         usage();
609                 }
610         }
611
612         ac -= optind;
613         av += optind;
614
615         if (ac > 0 && !host) {
616                 if (strrchr(*av, '@')) {
617                         p = xstrdup(*av);
618                         cp = strrchr(p, '@');
619                         if (cp == NULL || cp == p)
620                                 usage();
621                         options.user = p;
622                         *cp = '\0';
623                         host = ++cp;
624                 } else
625                         host = *av;
626                 if (ac > 1) {
627                         optind = optreset = 1;
628                         goto again;
629                 }
630                 ac--, av++;
631         }
632
633         /* Check that we got a host name. */
634         if (!host)
635                 usage();
636
637         OpenSSL_add_all_algorithms();
638         ERR_load_crypto_strings();
639
640         /* Initialize the command to execute on remote host. */
641         buffer_init(&command);
642
643         if (options.request_tty == REQUEST_TTY_YES ||
644             options.request_tty == REQUEST_TTY_FORCE)
645                 tty_flag = 1;
646
647         /*
648          * Save the command to execute on the remote host in a buffer. There
649          * is no limit on the length of the command, except by the maximum
650          * packet size.  Also sets the tty flag if there is no command.
651          */
652         if (!ac) {
653                 /* No command specified - execute shell on a tty. */
654                 tty_flag = options.request_tty != REQUEST_TTY_NO;
655                 if (subsystem_flag) {
656                         fprintf(stderr,
657                             "You must specify a subsystem to invoke.\n");
658                         usage();
659                 }
660         } else {
661                 /* A command has been specified.  Store it into the buffer. */
662                 for (i = 0; i < ac; i++) {
663                         if (i)
664                                 buffer_append(&command, " ", 1);
665                         buffer_append(&command, av[i], strlen(av[i]));
666                 }
667         }
668
669         /* Cannot fork to background if no command. */
670         if (fork_after_authentication_flag && buffer_len(&command) == 0 &&
671             !no_shell_flag)
672                 fatal("Cannot fork into background without a command "
673                     "to execute.");
674
675         /* Allocate a tty by default if no command specified. */
676         if (buffer_len(&command) == 0)
677                 tty_flag = options.request_tty != REQUEST_TTY_NO;
678
679         /* Force no tty */
680         if (options.request_tty == REQUEST_TTY_NO || muxclient_command != 0)
681                 tty_flag = 0;
682         /* Do not allocate a tty if stdin is not a tty. */
683         if ((!isatty(fileno(stdin)) || stdin_null_flag) &&
684             options.request_tty != REQUEST_TTY_FORCE) {
685                 if (tty_flag)
686                         logit("Pseudo-terminal will not be allocated because "
687                             "stdin is not a terminal.");
688                 tty_flag = 0;
689         }
690
691         /*
692          * Initialize "log" output.  Since we are the client all output
693          * actually goes to stderr.
694          */
695         log_init(argv0,
696             options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level,
697             SYSLOG_FACILITY_USER, !use_syslog);
698
699         /*
700          * Read per-user configuration file.  Ignore the system wide config
701          * file if the user specifies a config file on the command line.
702          */
703         if (config != NULL) {
704                 if (!read_config_file(config, host, &options, 0))
705                         fatal("Can't open user config file %.100s: "
706                             "%.100s", config, strerror(errno));
707         } else {
708                 r = snprintf(buf, sizeof buf, "%s/%s", pw->pw_dir,
709                     _PATH_SSH_USER_CONFFILE);
710                 if (r > 0 && (size_t)r < sizeof(buf))
711                         (void)read_config_file(buf, host, &options, 1);
712
713                 /* Read systemwide configuration file after user config. */
714                 (void)read_config_file(_PATH_HOST_CONFIG_FILE, host,
715                     &options, 0);
716         }
717
718         /* Fill configuration defaults. */
719         fill_default_options(&options);
720
721         channel_set_af(options.address_family);
722
723         /* reinit */
724         log_init(argv0, options.log_level, SYSLOG_FACILITY_USER, !use_syslog);
725
726         seed_rng();
727
728         if (options.user == NULL)
729                 options.user = xstrdup(pw->pw_name);
730
731         /* Get default port if port has not been set. */
732         if (options.port == 0) {
733                 sp = getservbyname(SSH_SERVICE_NAME, "tcp");
734                 options.port = sp ? ntohs(sp->s_port) : SSH_DEFAULT_PORT;
735         }
736
737         /* preserve host name given on command line for %n expansion */
738         host_arg = host;
739         if (options.hostname != NULL) {
740                 host = percent_expand(options.hostname,
741                     "h", host, (char *)NULL);
742         }
743
744         if (gethostname(thishost, sizeof(thishost)) == -1)
745                 fatal("gethostname: %s", strerror(errno));
746         strlcpy(shorthost, thishost, sizeof(shorthost));
747         shorthost[strcspn(thishost, ".")] = '\0';
748         snprintf(portstr, sizeof(portstr), "%d", options.port);
749
750         if (options.local_command != NULL) {
751                 debug3("expanding LocalCommand: %s", options.local_command);
752                 cp = options.local_command;
753                 options.local_command = percent_expand(cp, "d", pw->pw_dir,
754                     "h", host, "l", thishost, "n", host_arg, "r", options.user,
755                     "p", portstr, "u", pw->pw_name, "L", shorthost,
756                     (char *)NULL);
757                 debug3("expanded LocalCommand: %s", options.local_command);
758                 xfree(cp);
759         }
760
761         /* force lowercase for hostkey matching */
762         if (options.host_key_alias != NULL) {
763                 for (p = options.host_key_alias; *p; p++)
764                         if (isupper(*p))
765                                 *p = (char)tolower(*p);
766         }
767
768         if (options.proxy_command != NULL &&
769             strcmp(options.proxy_command, "none") == 0) {
770                 xfree(options.proxy_command);
771                 options.proxy_command = NULL;
772         }
773         if (options.control_path != NULL &&
774             strcmp(options.control_path, "none") == 0) {
775                 xfree(options.control_path);
776                 options.control_path = NULL;
777         }
778
779         if (options.control_path != NULL) {
780                 cp = tilde_expand_filename(options.control_path,
781                     original_real_uid);
782                 xfree(options.control_path);
783                 options.control_path = percent_expand(cp, "h", host,
784                     "l", thishost, "n", host_arg, "r", options.user,
785                     "p", portstr, "u", pw->pw_name, "L", shorthost,
786                     (char *)NULL);
787                 xfree(cp);
788         }
789         if (muxclient_command != 0 && options.control_path == NULL)
790                 fatal("No ControlPath specified for \"-O\" command");
791         if (options.control_path != NULL)
792                 muxclient(options.control_path);
793
794         timeout_ms = options.connection_timeout * 1000;
795
796         /* Open a connection to the remote host. */
797         if (ssh_connect(host, &hostaddr, options.port,
798             options.address_family, options.connection_attempts, &timeout_ms,
799             options.tcp_keep_alive, 
800 #ifdef HAVE_CYGWIN
801             options.use_privileged_port,
802 #else
803             original_effective_uid == 0 && options.use_privileged_port,
804 #endif
805             options.proxy_command) != 0)
806                 exit(255);
807
808         if (timeout_ms > 0)
809                 debug3("timeout: %d ms remain after connect", timeout_ms);
810
811         /*
812          * If we successfully made the connection, load the host private key
813          * in case we will need it later for combined rsa-rhosts
814          * authentication. This must be done before releasing extra
815          * privileges, because the file is only readable by root.
816          * If we cannot access the private keys, load the public keys
817          * instead and try to execute the ssh-keysign helper instead.
818          */
819         sensitive_data.nkeys = 0;
820         sensitive_data.keys = NULL;
821         sensitive_data.external_keysign = 0;
822         if (options.rhosts_rsa_authentication ||
823             options.hostbased_authentication) {
824                 sensitive_data.nkeys = 7;
825                 sensitive_data.keys = xcalloc(sensitive_data.nkeys,
826                     sizeof(Key));
827                 for (i = 0; i < sensitive_data.nkeys; i++)
828                         sensitive_data.keys[i] = NULL;
829
830                 PRIV_START;
831                 sensitive_data.keys[0] = key_load_private_type(KEY_RSA1,
832                     _PATH_HOST_KEY_FILE, "", NULL, NULL);
833                 sensitive_data.keys[1] = key_load_private_cert(KEY_DSA,
834                     _PATH_HOST_DSA_KEY_FILE, "", NULL);
835 #ifdef OPENSSL_HAS_ECC
836                 sensitive_data.keys[2] = key_load_private_cert(KEY_ECDSA,
837                     _PATH_HOST_ECDSA_KEY_FILE, "", NULL);
838 #endif
839                 sensitive_data.keys[3] = key_load_private_cert(KEY_RSA,
840                     _PATH_HOST_RSA_KEY_FILE, "", NULL);
841                 sensitive_data.keys[4] = key_load_private_type(KEY_DSA,
842                     _PATH_HOST_DSA_KEY_FILE, "", NULL, NULL);
843 #ifdef OPENSSL_HAS_ECC
844                 sensitive_data.keys[5] = key_load_private_type(KEY_ECDSA,
845                     _PATH_HOST_ECDSA_KEY_FILE, "", NULL, NULL);
846 #endif
847                 sensitive_data.keys[6] = key_load_private_type(KEY_RSA,
848                     _PATH_HOST_RSA_KEY_FILE, "", NULL, NULL);
849                 PRIV_END;
850
851                 if (options.hostbased_authentication == 1 &&
852                     sensitive_data.keys[0] == NULL &&
853                     sensitive_data.keys[4] == NULL &&
854                     sensitive_data.keys[5] == NULL &&
855                     sensitive_data.keys[6] == NULL) {
856                         sensitive_data.keys[1] = key_load_cert(
857                             _PATH_HOST_DSA_KEY_FILE);
858 #ifdef OPENSSL_HAS_ECC
859                         sensitive_data.keys[2] = key_load_cert(
860                             _PATH_HOST_ECDSA_KEY_FILE);
861 #endif
862                         sensitive_data.keys[3] = key_load_cert(
863                             _PATH_HOST_RSA_KEY_FILE);
864                         sensitive_data.keys[4] = key_load_public(
865                             _PATH_HOST_DSA_KEY_FILE, NULL);
866 #ifdef OPENSSL_HAS_ECC
867                         sensitive_data.keys[5] = key_load_public(
868                             _PATH_HOST_ECDSA_KEY_FILE, NULL);
869 #endif
870                         sensitive_data.keys[6] = key_load_public(
871                             _PATH_HOST_RSA_KEY_FILE, NULL);
872                         sensitive_data.external_keysign = 1;
873                 }
874         }
875         /*
876          * Get rid of any extra privileges that we may have.  We will no
877          * longer need them.  Also, extra privileges could make it very hard
878          * to read identity files and other non-world-readable files from the
879          * user's home directory if it happens to be on a NFS volume where
880          * root is mapped to nobody.
881          */
882         if (original_effective_uid == 0) {
883                 PRIV_START;
884                 permanently_set_uid(pw);
885         }
886
887         /*
888          * Now that we are back to our own permissions, create ~/.ssh
889          * directory if it doesn't already exist.
890          */
891         r = snprintf(buf, sizeof buf, "%s%s%s", pw->pw_dir,
892             strcmp(pw->pw_dir, "/") ? "/" : "", _PATH_SSH_USER_DIR);
893         if (r > 0 && (size_t)r < sizeof(buf) && stat(buf, &st) < 0) {
894 #ifdef WITH_SELINUX
895                 ssh_selinux_setfscreatecon(buf);
896 #endif
897                 if (mkdir(buf, 0700) < 0)
898                         error("Could not create directory '%.200s'.", buf);
899 #ifdef WITH_SELINUX
900                 ssh_selinux_setfscreatecon(NULL);
901 #endif
902         }
903         /* load options.identity_files */
904         load_public_identity_files();
905
906         /* Expand ~ in known host file names. */
907         tilde_expand_paths(options.system_hostfiles,
908             options.num_system_hostfiles);
909         tilde_expand_paths(options.user_hostfiles, options.num_user_hostfiles);
910
911         signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */
912         signal(SIGCHLD, main_sigchld_handler);
913
914         /* Log into the remote system.  Never returns if the login fails. */
915         ssh_login(&sensitive_data, host, (struct sockaddr *)&hostaddr,
916             options.port, pw, timeout_ms);
917
918         if (packet_connection_is_on_socket()) {
919                 verbose("Authenticated to %s ([%s]:%d).", host,
920                     get_remote_ipaddr(), get_remote_port());
921         } else {
922                 verbose("Authenticated to %s (via proxy).", host);
923         }
924
925         /* We no longer need the private host keys.  Clear them now. */
926         if (sensitive_data.nkeys != 0) {
927                 for (i = 0; i < sensitive_data.nkeys; i++) {
928                         if (sensitive_data.keys[i] != NULL) {
929                                 /* Destroys contents safely */
930                                 debug3("clear hostkey %d", i);
931                                 key_free(sensitive_data.keys[i]);
932                                 sensitive_data.keys[i] = NULL;
933                         }
934                 }
935                 xfree(sensitive_data.keys);
936         }
937         for (i = 0; i < options.num_identity_files; i++) {
938                 if (options.identity_files[i]) {
939                         xfree(options.identity_files[i]);
940                         options.identity_files[i] = NULL;
941                 }
942                 if (options.identity_keys[i]) {
943                         key_free(options.identity_keys[i]);
944                         options.identity_keys[i] = NULL;
945                 }
946         }
947
948         exit_status = compat20 ? ssh_session2() : ssh_session();
949         packet_close();
950
951         if (options.control_path != NULL && muxserver_sock != -1)
952                 unlink(options.control_path);
953
954         /* Kill ProxyCommand if it is running. */
955         ssh_kill_proxy_command();
956
957         return exit_status;
958 }
959
960 static void
961 control_persist_detach(void)
962 {
963         pid_t pid;
964         int devnull;
965
966         debug("%s: backgrounding master process", __func__);
967
968         /*
969          * master (current process) into the background, and make the
970          * foreground process a client of the backgrounded master.
971          */
972         switch ((pid = fork())) {
973         case -1:
974                 fatal("%s: fork: %s", __func__, strerror(errno));
975         case 0:
976                 /* Child: master process continues mainloop */
977                 break;
978         default:
979                 /* Parent: set up mux slave to connect to backgrounded master */
980                 debug2("%s: background process is %ld", __func__, (long)pid);
981                 stdin_null_flag = ostdin_null_flag;
982                 options.request_tty = orequest_tty;
983                 tty_flag = otty_flag;
984                 close(muxserver_sock);
985                 muxserver_sock = -1;
986                 options.control_master = SSHCTL_MASTER_NO;
987                 muxclient(options.control_path);
988                 /* muxclient() doesn't return on success. */
989                 fatal("Failed to connect to new control master");
990         }
991         if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1) {
992                 error("%s: open(\"/dev/null\"): %s", __func__,
993                     strerror(errno));
994         } else {
995                 if (dup2(devnull, STDIN_FILENO) == -1 ||
996                     dup2(devnull, STDOUT_FILENO) == -1)
997                         error("%s: dup2: %s", __func__, strerror(errno));
998                 if (devnull > STDERR_FILENO)
999                         close(devnull);
1000         }
1001         setproctitle("%s [mux]", options.control_path);
1002 }
1003
1004 /* Do fork() after authentication. Used by "ssh -f" */
1005 static void
1006 fork_postauth(void)
1007 {
1008         if (need_controlpersist_detach)
1009                 control_persist_detach();
1010         debug("forking to background");
1011         fork_after_authentication_flag = 0;
1012         if (daemon(1, 1) < 0)
1013                 fatal("daemon() failed: %.200s", strerror(errno));
1014 }
1015
1016 /* Callback for remote forward global requests */
1017 static void
1018 ssh_confirm_remote_forward(int type, u_int32_t seq, void *ctxt)
1019 {
1020         Forward *rfwd = (Forward *)ctxt;
1021
1022         /* XXX verbose() on failure? */
1023         debug("remote forward %s for: listen %d, connect %s:%d",
1024             type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure",
1025             rfwd->listen_port, rfwd->connect_host, rfwd->connect_port);
1026         if (type == SSH2_MSG_REQUEST_SUCCESS && rfwd->listen_port == 0) {
1027                 rfwd->allocated_port = packet_get_int();
1028                 logit("Allocated port %u for remote forward to %s:%d",
1029                     rfwd->allocated_port,
1030                     rfwd->connect_host, rfwd->connect_port);
1031         }
1032         
1033         if (type == SSH2_MSG_REQUEST_FAILURE) {
1034                 if (options.exit_on_forward_failure)
1035                         fatal("Error: remote port forwarding failed for "
1036                             "listen port %d", rfwd->listen_port);
1037                 else
1038                         logit("Warning: remote port forwarding failed for "
1039                             "listen port %d", rfwd->listen_port);
1040         }
1041         if (++remote_forward_confirms_received == options.num_remote_forwards) {
1042                 debug("All remote forwarding requests processed");
1043                 if (fork_after_authentication_flag)
1044                         fork_postauth();
1045         }
1046 }
1047
1048 static void
1049 client_cleanup_stdio_fwd(int id, void *arg)
1050 {
1051         debug("stdio forwarding: done");
1052         cleanup_exit(0);
1053 }
1054
1055 static int
1056 client_setup_stdio_fwd(const char *host_to_connect, u_short port_to_connect)
1057 {
1058         Channel *c;
1059         int in, out;
1060
1061         debug3("client_setup_stdio_fwd %s:%d", host_to_connect,
1062             port_to_connect);
1063
1064         in = dup(STDIN_FILENO);
1065         out = dup(STDOUT_FILENO);
1066         if (in < 0 || out < 0)
1067                 fatal("channel_connect_stdio_fwd: dup() in/out failed");
1068
1069         if ((c = channel_connect_stdio_fwd(host_to_connect, port_to_connect,
1070             in, out)) == NULL)
1071                 return 0;
1072         channel_register_cleanup(c->self, client_cleanup_stdio_fwd, 0);
1073         return 1;
1074 }
1075
1076 static void
1077 ssh_init_forwarding(void)
1078 {
1079         int success = 0;
1080         int i;
1081
1082         if (stdio_forward_host != NULL) {
1083                 if (!compat20) {
1084                         fatal("stdio forwarding require Protocol 2");
1085                 }
1086                 if (!client_setup_stdio_fwd(stdio_forward_host,
1087                     stdio_forward_port))
1088                         fatal("Failed to connect in stdio forward mode.");
1089         }
1090
1091         /* Initiate local TCP/IP port forwardings. */
1092         for (i = 0; i < options.num_local_forwards; i++) {
1093                 debug("Local connections to %.200s:%d forwarded to remote "
1094                     "address %.200s:%d",
1095                     (options.local_forwards[i].listen_host == NULL) ?
1096                     (options.gateway_ports ? "*" : "LOCALHOST") :
1097                     options.local_forwards[i].listen_host,
1098                     options.local_forwards[i].listen_port,
1099                     options.local_forwards[i].connect_host,
1100                     options.local_forwards[i].connect_port);
1101                 success += channel_setup_local_fwd_listener(
1102                     options.local_forwards[i].listen_host,
1103                     options.local_forwards[i].listen_port,
1104                     options.local_forwards[i].connect_host,
1105                     options.local_forwards[i].connect_port,
1106                     options.gateway_ports);
1107         }
1108         if (i > 0 && success != i && options.exit_on_forward_failure)
1109                 fatal("Could not request local forwarding.");
1110         if (i > 0 && success == 0)
1111                 error("Could not request local forwarding.");
1112
1113         /* Initiate remote TCP/IP port forwardings. */
1114         for (i = 0; i < options.num_remote_forwards; i++) {
1115                 debug("Remote connections from %.200s:%d forwarded to "
1116                     "local address %.200s:%d",
1117                     (options.remote_forwards[i].listen_host == NULL) ?
1118                     "LOCALHOST" : options.remote_forwards[i].listen_host,
1119                     options.remote_forwards[i].listen_port,
1120                     options.remote_forwards[i].connect_host,
1121                     options.remote_forwards[i].connect_port);
1122                 if (channel_request_remote_forwarding(
1123                     options.remote_forwards[i].listen_host,
1124                     options.remote_forwards[i].listen_port,
1125                     options.remote_forwards[i].connect_host,
1126                     options.remote_forwards[i].connect_port) < 0) {
1127                         if (options.exit_on_forward_failure)
1128                                 fatal("Could not request remote forwarding.");
1129                         else
1130                                 logit("Warning: Could not request remote "
1131                                     "forwarding.");
1132                 }
1133                 client_register_global_confirm(ssh_confirm_remote_forward,
1134                     &options.remote_forwards[i]);
1135         }
1136
1137         /* Initiate tunnel forwarding. */
1138         if (options.tun_open != SSH_TUNMODE_NO) {
1139                 if (client_request_tun_fwd(options.tun_open,
1140                     options.tun_local, options.tun_remote) == -1) {
1141                         if (options.exit_on_forward_failure)
1142                                 fatal("Could not request tunnel forwarding.");
1143                         else
1144                                 error("Could not request tunnel forwarding.");
1145                 }
1146         }                       
1147 }
1148
1149 static void
1150 check_agent_present(void)
1151 {
1152         if (options.forward_agent) {
1153                 /* Clear agent forwarding if we don't have an agent. */
1154                 if (!ssh_agent_present())
1155                         options.forward_agent = 0;
1156         }
1157 }
1158
1159 static int
1160 ssh_session(void)
1161 {
1162         int type;
1163         int interactive = 0;
1164         int have_tty = 0;
1165         struct winsize ws;
1166         char *cp;
1167         const char *display;
1168
1169         /* Enable compression if requested. */
1170         if (options.compression) {
1171                 debug("Requesting compression at level %d.",
1172                     options.compression_level);
1173
1174                 if (options.compression_level < 1 ||
1175                     options.compression_level > 9)
1176                         fatal("Compression level must be from 1 (fast) to "
1177                             "9 (slow, best).");
1178
1179                 /* Send the request. */
1180                 packet_start(SSH_CMSG_REQUEST_COMPRESSION);
1181                 packet_put_int(options.compression_level);
1182                 packet_send();
1183                 packet_write_wait();
1184                 type = packet_read();
1185                 if (type == SSH_SMSG_SUCCESS)
1186                         packet_start_compression(options.compression_level);
1187                 else if (type == SSH_SMSG_FAILURE)
1188                         logit("Warning: Remote host refused compression.");
1189                 else
1190                         packet_disconnect("Protocol error waiting for "
1191                             "compression response.");
1192         }
1193         /* Allocate a pseudo tty if appropriate. */
1194         if (tty_flag) {
1195                 debug("Requesting pty.");
1196
1197                 /* Start the packet. */
1198                 packet_start(SSH_CMSG_REQUEST_PTY);
1199
1200                 /* Store TERM in the packet.  There is no limit on the
1201                    length of the string. */
1202                 cp = getenv("TERM");
1203                 if (!cp)
1204                         cp = "";
1205                 packet_put_cstring(cp);
1206
1207                 /* Store window size in the packet. */
1208                 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
1209                         memset(&ws, 0, sizeof(ws));
1210                 packet_put_int((u_int)ws.ws_row);
1211                 packet_put_int((u_int)ws.ws_col);
1212                 packet_put_int((u_int)ws.ws_xpixel);
1213                 packet_put_int((u_int)ws.ws_ypixel);
1214
1215                 /* Store tty modes in the packet. */
1216                 tty_make_modes(fileno(stdin), NULL);
1217
1218                 /* Send the packet, and wait for it to leave. */
1219                 packet_send();
1220                 packet_write_wait();
1221
1222                 /* Read response from the server. */
1223                 type = packet_read();
1224                 if (type == SSH_SMSG_SUCCESS) {
1225                         interactive = 1;
1226                         have_tty = 1;
1227                 } else if (type == SSH_SMSG_FAILURE)
1228                         logit("Warning: Remote host failed or refused to "
1229                             "allocate a pseudo tty.");
1230                 else
1231                         packet_disconnect("Protocol error waiting for pty "
1232                             "request response.");
1233         }
1234         /* Request X11 forwarding if enabled and DISPLAY is set. */
1235         display = getenv("DISPLAY");
1236         if (options.forward_x11 && display != NULL) {
1237                 char *proto, *data;
1238                 /* Get reasonable local authentication information. */
1239                 client_x11_get_proto(display, options.xauth_location,
1240                     options.forward_x11_trusted, 
1241                     options.forward_x11_timeout,
1242                     &proto, &data);
1243                 /* Request forwarding with authentication spoofing. */
1244                 debug("Requesting X11 forwarding with authentication "
1245                     "spoofing.");
1246                 x11_request_forwarding_with_spoofing(0, display, proto,
1247                     data, 0);
1248                 /* Read response from the server. */
1249                 type = packet_read();
1250                 if (type == SSH_SMSG_SUCCESS) {
1251                         interactive = 1;
1252                 } else if (type == SSH_SMSG_FAILURE) {
1253                         logit("Warning: Remote host denied X11 forwarding.");
1254                 } else {
1255                         packet_disconnect("Protocol error waiting for X11 "
1256                             "forwarding");
1257                 }
1258         }
1259         /* Tell the packet module whether this is an interactive session. */
1260         packet_set_interactive(interactive,
1261             options.ip_qos_interactive, options.ip_qos_bulk);
1262
1263         /* Request authentication agent forwarding if appropriate. */
1264         check_agent_present();
1265
1266         if (options.forward_agent) {
1267                 debug("Requesting authentication agent forwarding.");
1268                 auth_request_forwarding();
1269
1270                 /* Read response from the server. */
1271                 type = packet_read();
1272                 packet_check_eom();
1273                 if (type != SSH_SMSG_SUCCESS)
1274                         logit("Warning: Remote host denied authentication agent forwarding.");
1275         }
1276
1277         /* Initiate port forwardings. */
1278         ssh_init_forwarding();
1279
1280         /* Execute a local command */
1281         if (options.local_command != NULL &&
1282             options.permit_local_command)
1283                 ssh_local_cmd(options.local_command);
1284
1285         /*
1286          * If requested and we are not interested in replies to remote
1287          * forwarding requests, then let ssh continue in the background.
1288          */
1289         if (fork_after_authentication_flag) {
1290                 if (options.exit_on_forward_failure &&
1291                     options.num_remote_forwards > 0) {
1292                         debug("deferring postauth fork until remote forward "
1293                             "confirmation received");
1294                 } else
1295                         fork_postauth();
1296         }
1297
1298         /*
1299          * If a command was specified on the command line, execute the
1300          * command now. Otherwise request the server to start a shell.
1301          */
1302         if (buffer_len(&command) > 0) {
1303                 int len = buffer_len(&command);
1304                 if (len > 900)
1305                         len = 900;
1306                 debug("Sending command: %.*s", len,
1307                     (u_char *)buffer_ptr(&command));
1308                 packet_start(SSH_CMSG_EXEC_CMD);
1309                 packet_put_string(buffer_ptr(&command), buffer_len(&command));
1310                 packet_send();
1311                 packet_write_wait();
1312         } else {
1313                 debug("Requesting shell.");
1314                 packet_start(SSH_CMSG_EXEC_SHELL);
1315                 packet_send();
1316                 packet_write_wait();
1317         }
1318
1319         /* Enter the interactive session. */
1320         return client_loop(have_tty, tty_flag ?
1321             options.escape_char : SSH_ESCAPECHAR_NONE, 0);
1322 }
1323
1324 /* request pty/x11/agent/tcpfwd/shell for channel */
1325 static void
1326 ssh_session2_setup(int id, int success, void *arg)
1327 {
1328         extern char **environ;
1329         const char *display;
1330         int interactive = tty_flag;
1331
1332         if (!success)
1333                 return; /* No need for error message, channels code sens one */
1334
1335         display = getenv("DISPLAY");
1336         if (options.forward_x11 && display != NULL) {
1337                 char *proto, *data;
1338                 /* Get reasonable local authentication information. */
1339                 client_x11_get_proto(display, options.xauth_location,
1340                     options.forward_x11_trusted,
1341                     options.forward_x11_timeout, &proto, &data);
1342                 /* Request forwarding with authentication spoofing. */
1343                 debug("Requesting X11 forwarding with authentication "
1344                     "spoofing.");
1345                 x11_request_forwarding_with_spoofing(id, display, proto,
1346                     data, 1);
1347                 client_expect_confirm(id, "X11 forwarding", CONFIRM_WARN);
1348                 /* XXX exit_on_forward_failure */
1349                 interactive = 1;
1350         }
1351
1352         check_agent_present();
1353         if (options.forward_agent) {
1354                 debug("Requesting authentication agent forwarding.");
1355                 channel_request_start(id, "auth-agent-req@openssh.com", 0);
1356                 packet_send();
1357         }
1358
1359         client_session2_setup(id, tty_flag, subsystem_flag, getenv("TERM"),
1360             NULL, fileno(stdin), &command, environ);
1361 }
1362
1363 /* open new channel for a session */
1364 static int
1365 ssh_session2_open(void)
1366 {
1367         Channel *c;
1368         int window, packetmax, in, out, err;
1369         int sock;
1370         int socksize;
1371         int socksizelen = sizeof(int);
1372
1373         if (stdin_null_flag) {
1374                 in = open(_PATH_DEVNULL, O_RDONLY);
1375         } else {
1376                 in = dup(STDIN_FILENO);
1377         }
1378         out = dup(STDOUT_FILENO);
1379         err = dup(STDERR_FILENO);
1380
1381         if (in < 0 || out < 0 || err < 0)
1382                 fatal("dup() in/out/err failed");
1383
1384         /* enable nonblocking unless tty */
1385         if (!isatty(in))
1386                 set_nonblock(in);
1387         if (!isatty(out))
1388                 set_nonblock(out);
1389         if (!isatty(err))
1390                 set_nonblock(err);
1391
1392         /* we need to check to see if what they want to do about buffer */
1393         /* sizes here. In a hpn to nonhpn connection we want to limit */
1394         /* the window size to something reasonable in case the far side */
1395         /* has the large window bug. In hpn to hpn connection we want to */
1396         /* use the max window size but allow the user to override it */
1397         /* lastly if they disabled hpn then use the ssh std window size */
1398
1399         /* so why don't we just do a getsockopt() here and set the */
1400         /* ssh window to that? In the case of a autotuning receive */
1401         /* window the window would get stuck at the initial buffer */
1402         /* size generally less than 96k. Therefore we need to set the */
1403         /* maximum ssh window size to the maximum hpn buffer size */
1404         /* unless the user has specifically set the tcprcvbufpoll */
1405         /* to no. In which case we *can* just set the window to the */
1406         /* minimum of the hpn buffer size and tcp receive buffer size */
1407
1408         if (tty_flag)
1409                 options.hpn_buffer_size = CHAN_SES_WINDOW_DEFAULT;
1410         else
1411                 options.hpn_buffer_size = 2*1024*1024;
1412
1413         if (datafellows & SSH_BUG_LARGEWINDOW)
1414         {
1415                 debug("HPN to Non-HPN Connection");
1416         }
1417         else
1418         {
1419                 if (options.tcp_rcv_buf_poll <= 0)
1420                 {
1421                         sock = socket(AF_INET, SOCK_STREAM, 0);
1422                         getsockopt(sock, SOL_SOCKET, SO_RCVBUF,
1423                                    &socksize, &socksizelen);
1424                         close(sock);
1425                         debug("socksize %d", socksize);
1426                         options.hpn_buffer_size = socksize;
1427                         debug ("HPNBufferSize set to TCP RWIN: %d", options.hpn_buffer_size);
1428                 }
1429                 else
1430                 {
1431                         if (options.tcp_rcv_buf > 0)
1432                         {
1433                                 /*create a socket but don't connect it */
1434                                 /* we use that the get the rcv socket size */
1435                                 sock = socket(AF_INET, SOCK_STREAM, 0);
1436                                 /* if they are using the tcp_rcv_buf option */
1437                                 /* attempt to set the buffer size to that */
1438                                 if (options.tcp_rcv_buf)
1439                                         setsockopt(sock, SOL_SOCKET, SO_RCVBUF, (void *)&options.tcp_rcv_buf,
1440                                                    sizeof(options.tcp_rcv_buf));
1441                                 getsockopt(sock, SOL_SOCKET, SO_RCVBUF,
1442                                            &socksize, &socksizelen);
1443                                 close(sock);
1444                                 debug("socksize %d", socksize);
1445                                 options.hpn_buffer_size = socksize;
1446                                 debug ("HPNBufferSize set to user TCPRcvBuf: %d", options.hpn_buffer_size);
1447                         }
1448                 }
1449
1450         }
1451
1452         debug("Final hpn_buffer_size = %d", options.hpn_buffer_size);
1453
1454         window = options.hpn_buffer_size;
1455
1456         channel_set_hpn(options.hpn_disabled, options.hpn_buffer_size);
1457
1458         packetmax = CHAN_SES_PACKET_DEFAULT;
1459         if (tty_flag) {
1460                 window = 4*CHAN_SES_PACKET_DEFAULT;
1461                 window >>= 1;
1462                 packetmax >>= 1;
1463         }
1464         c = channel_new(
1465             "session", SSH_CHANNEL_OPENING, in, out, err,
1466             window, packetmax, CHAN_EXTENDED_WRITE,
1467             "client-session", /*nonblock*/0);
1468         if ((options.tcp_rcv_buf_poll > 0) && (!options.hpn_disabled)) {
1469                 c->dynamic_window = 1;
1470                 debug ("Enabled Dynamic Window Scaling\n");
1471         }
1472         debug3("ssh_session2_open: channel_new: %d", c->self);
1473
1474         channel_send_open(c->self);
1475         if (!no_shell_flag)
1476                 channel_register_open_confirm(c->self,
1477                     ssh_session2_setup, NULL);
1478
1479         return c->self;
1480 }
1481
1482 static int
1483 ssh_session2(void)
1484 {
1485         int id = -1;
1486
1487         /* XXX should be pre-session */
1488         ssh_init_forwarding();
1489
1490         /* Start listening for multiplex clients */
1491         muxserver_listen();
1492
1493         /*
1494          * If we are in control persist mode, then prepare to background
1495          * ourselves and have a foreground client attach as a control
1496          * slave. NB. we must save copies of the flags that we override for
1497          * the backgrounding, since we defer attachment of the slave until
1498          * after the connection is fully established (in particular,
1499          * async rfwd replies have been received for ExitOnForwardFailure).
1500          */
1501         if (options.control_persist && muxserver_sock != -1) {
1502                 ostdin_null_flag = stdin_null_flag;
1503                 ono_shell_flag = no_shell_flag;
1504                 orequest_tty = options.request_tty;
1505                 otty_flag = tty_flag;
1506                 stdin_null_flag = 1;
1507                 no_shell_flag = 1;
1508                 tty_flag = 0;
1509                 if (!fork_after_authentication_flag)
1510                         need_controlpersist_detach = 1;
1511                 fork_after_authentication_flag = 1;
1512         }
1513
1514         if (!no_shell_flag || (datafellows & SSH_BUG_DUMMYCHAN))
1515                 id = ssh_session2_open();
1516
1517         /* If we don't expect to open a new session, then disallow it */
1518         if (options.control_master == SSHCTL_MASTER_NO &&
1519             (datafellows & SSH_NEW_OPENSSH)) {
1520                 debug("Requesting no-more-sessions@openssh.com");
1521                 packet_start(SSH2_MSG_GLOBAL_REQUEST);
1522                 packet_put_cstring("no-more-sessions@openssh.com");
1523                 packet_put_char(0);
1524                 packet_send();
1525         }
1526
1527         /* Execute a local command */
1528         if (options.local_command != NULL &&
1529             options.permit_local_command)
1530                 ssh_local_cmd(options.local_command);
1531
1532         /*
1533          * If requested and we are not interested in replies to remote
1534          * forwarding requests, then let ssh continue in the background.
1535          */
1536         if (fork_after_authentication_flag) {
1537                 if (options.exit_on_forward_failure &&
1538                     options.num_remote_forwards > 0) {
1539                         debug("deferring postauth fork until remote forward "
1540                             "confirmation received");
1541                 } else
1542                         fork_postauth();
1543         }
1544
1545         if (options.use_roaming)
1546                 request_roaming();
1547
1548         return client_loop(tty_flag, tty_flag ?
1549             options.escape_char : SSH_ESCAPECHAR_NONE, id);
1550 }
1551
1552 static void
1553 load_public_identity_files(void)
1554 {
1555         char *filename, *cp, thishost[NI_MAXHOST];
1556         char *pwdir = NULL, *pwname = NULL;
1557         int i = 0;
1558         Key *public;
1559         struct passwd *pw;
1560         u_int n_ids;
1561         char *identity_files[SSH_MAX_IDENTITY_FILES];
1562         Key *identity_keys[SSH_MAX_IDENTITY_FILES];
1563 #ifdef ENABLE_PKCS11
1564         Key **keys;
1565         int nkeys;
1566 #endif /* PKCS11 */
1567
1568         n_ids = 0;
1569         bzero(identity_files, sizeof(identity_files));
1570         bzero(identity_keys, sizeof(identity_keys));
1571
1572 #ifdef ENABLE_PKCS11
1573         if (options.pkcs11_provider != NULL &&
1574             options.num_identity_files < SSH_MAX_IDENTITY_FILES &&
1575             (pkcs11_init(!options.batch_mode) == 0) &&
1576             (nkeys = pkcs11_add_provider(options.pkcs11_provider, NULL,
1577             &keys)) > 0) {
1578                 for (i = 0; i < nkeys; i++) {
1579                         if (n_ids >= SSH_MAX_IDENTITY_FILES) {
1580                                 key_free(keys[i]);
1581                                 continue;
1582                         }
1583                         identity_keys[n_ids] = keys[i];
1584                         identity_files[n_ids] =
1585                             xstrdup(options.pkcs11_provider); /* XXX */
1586                         n_ids++;
1587                 }
1588                 xfree(keys);
1589         }
1590 #endif /* ENABLE_PKCS11 */
1591         if ((pw = getpwuid(original_real_uid)) == NULL)
1592                 fatal("load_public_identity_files: getpwuid failed");
1593         pwname = xstrdup(pw->pw_name);
1594         pwdir = xstrdup(pw->pw_dir);
1595         if (gethostname(thishost, sizeof(thishost)) == -1)
1596                 fatal("load_public_identity_files: gethostname: %s",
1597                     strerror(errno));
1598         for (i = 0; i < options.num_identity_files; i++) {
1599                 if (n_ids >= SSH_MAX_IDENTITY_FILES) {
1600                         xfree(options.identity_files[i]);
1601                         continue;
1602                 }
1603                 cp = tilde_expand_filename(options.identity_files[i],
1604                     original_real_uid);
1605                 filename = percent_expand(cp, "d", pwdir,
1606                     "u", pwname, "l", thishost, "h", host,
1607                     "r", options.user, (char *)NULL);
1608                 xfree(cp);
1609                 public = key_load_public(filename, NULL);
1610                 debug("identity file %s type %d", filename,
1611                     public ? public->type : -1);
1612                 xfree(options.identity_files[i]);
1613                 identity_files[n_ids] = filename;
1614                 identity_keys[n_ids] = public;
1615
1616                 if (++n_ids >= SSH_MAX_IDENTITY_FILES)
1617                         continue;
1618
1619                 /* Try to add the certificate variant too */
1620                 xasprintf(&cp, "%s-cert", filename);
1621                 public = key_load_public(cp, NULL);
1622                 debug("identity file %s type %d", cp,
1623                     public ? public->type : -1);
1624                 if (public == NULL) {
1625                         xfree(cp);
1626                         continue;
1627                 }
1628                 if (!key_is_cert(public)) {
1629                         debug("%s: key %s type %s is not a certificate",
1630                             __func__, cp, key_type(public));
1631                         key_free(public);
1632                         xfree(cp);
1633                         continue;
1634                 }
1635                 identity_keys[n_ids] = public;
1636                 /* point to the original path, most likely the private key */
1637                 identity_files[n_ids] = xstrdup(filename);
1638                 n_ids++;
1639         }
1640         options.num_identity_files = n_ids;
1641         memcpy(options.identity_files, identity_files, sizeof(identity_files));
1642         memcpy(options.identity_keys, identity_keys, sizeof(identity_keys));
1643
1644         bzero(pwname, strlen(pwname));
1645         xfree(pwname);
1646         bzero(pwdir, strlen(pwdir));
1647         xfree(pwdir);
1648 }
1649
1650 static void
1651 main_sigchld_handler(int sig)
1652 {
1653         int save_errno = errno;
1654         pid_t pid;
1655         int status;
1656
1657         while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
1658             (pid < 0 && errno == EINTR))
1659                 ;
1660
1661         signal(sig, main_sigchld_handler);
1662         errno = save_errno;
1663 }
1664