- (dtucker) [contrib/cygwin/ssh-{host,user}-config] Add ECDSA key
[openssh-git.git] / ssh.c
blobd32ef78b0d150d09ca558e9ab606f0ea5939a75b
1 /* $OpenBSD: ssh.c,v 1.356 2011/01/06 22:23:53 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  */
43 #include "includes.h"
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>
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>
71 #include <netinet/in.h>
72 #include <arpa/inet.h>
74 #include <openssl/evp.h>
75 #include <openssl/err.h>
76 #include "openbsd-compat/openssl-compat.h"
77 #include "openbsd-compat/sys-queue.h"
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"
108 #ifdef ENABLE_PKCS11
109 #include "ssh-pkcs11.h"
110 #endif
112 extern char *__progname;
114 /* Flag indicating whether debug mode is on.  May be set on the command line. */
115 int debug_flag = 0;
117 /* Flag indicating whether a tty should be allocated */
118 int tty_flag = 0;
119 int no_tty_flag = 0;
120 int force_tty_flag = 0;
122 /* don't exec a shell */
123 int no_shell_flag = 0;
126  * Flag indicating that nothing should be read from stdin.  This can be set
127  * on the command line.
128  */
129 int stdin_null_flag = 0;
132  * Flag indicating that the current process should be backgrounded and
133  * a new slave launched in the foreground for ControlPersist.
134  */
135 int need_controlpersist_detach = 0;
137 /* Copies of flags for ControlPersist foreground slave */
138 int ostdin_null_flag, ono_shell_flag, ono_tty_flag, otty_flag;
141  * Flag indicating that ssh should fork after authentication.  This is useful
142  * so that the passphrase can be entered manually, and then ssh goes to the
143  * background.
144  */
145 int fork_after_authentication_flag = 0;
147 /* forward stdio to remote host and port */
148 char *stdio_forward_host = NULL;
149 int stdio_forward_port = 0;
152  * General data structure for command line options and options configurable
153  * in configuration files.  See readconf.h.
154  */
155 Options options;
157 /* optional user configfile */
158 char *config = NULL;
161  * Name of the host we are connecting to.  This is the name given on the
162  * command line, or the HostName specified for the user-supplied name in a
163  * configuration file.
164  */
165 char *host;
167 /* socket address the host resolves to */
168 struct sockaddr_storage hostaddr;
170 /* Private host keys. */
171 Sensitive sensitive_data;
173 /* Original real UID. */
174 uid_t original_real_uid;
175 uid_t original_effective_uid;
177 /* command to be executed */
178 Buffer command;
180 /* Should we execute a command or invoke a subsystem? */
181 int subsystem_flag = 0;
183 /* # of replies received for global requests */
184 static int remote_forward_confirms_received = 0;
186 /* mux.c */
187 extern int muxserver_sock;
188 extern u_int muxclient_command;
190 /* Prints a help message to the user.  This function never returns. */
192 static void
193 usage(void)
195         fprintf(stderr,
196 "usage: ssh [-1246AaCfgKkMNnqsTtVvXxYy] [-b bind_address] [-c cipher_spec]\n"
197 "           [-D [bind_address:]port] [-e escape_char] [-F configfile]\n"
198 "           [-I pkcs11] [-i identity_file]\n"
199 "           [-L [bind_address:]port:host:hostport]\n"
200 "           [-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port]\n"
201 "           [-R [bind_address:]port:host:hostport] [-S ctl_path]\n"
202 "           [-W host:port] [-w local_tun[:remote_tun]]\n"
203 "           [user@]hostname [command]\n"
204         );
205         exit(255);
208 static int ssh_session(void);
209 static int ssh_session2(void);
210 static void load_public_identity_files(void);
211 static void main_sigchld_handler(int);
213 /* from muxclient.c */
214 void muxclient(const char *);
215 void muxserver_listen(void);
218  * Main program for the ssh client.
219  */
221 main(int ac, char **av)
223         int i, r, opt, exit_status, use_syslog;
224         char *p, *cp, *line, *argv0, buf[MAXPATHLEN], *host_arg;
225         struct stat st;
226         struct passwd *pw;
227         int dummy, timeout_ms;
228         extern int optind, optreset;
229         extern char *optarg;
230         struct servent *sp;
231         Forward fwd;
233         /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
234         sanitise_stdfd();
236         __progname = ssh_get_progname(av[0]);
237         init_rng();
239         /*
240          * Discard other fds that are hanging around. These can cause problem
241          * with backgrounded ssh processes started by ControlPersist.
242          */
243         closefrom(STDERR_FILENO + 1);
245         /*
246          * Save the original real uid.  It will be needed later (uid-swapping
247          * may clobber the real uid).
248          */
249         original_real_uid = getuid();
250         original_effective_uid = geteuid();
252         /*
253          * Use uid-swapping to give up root privileges for the duration of
254          * option processing.  We will re-instantiate the rights when we are
255          * ready to create the privileged port, and will permanently drop
256          * them when the port has been created (actually, when the connection
257          * has been made, as we may need to create the port several times).
258          */
259         PRIV_END;
261 #ifdef HAVE_SETRLIMIT
262         /* If we are installed setuid root be careful to not drop core. */
263         if (original_real_uid != original_effective_uid) {
264                 struct rlimit rlim;
265                 rlim.rlim_cur = rlim.rlim_max = 0;
266                 if (setrlimit(RLIMIT_CORE, &rlim) < 0)
267                         fatal("setrlimit failed: %.100s", strerror(errno));
268         }
269 #endif
270         /* Get user data. */
271         pw = getpwuid(original_real_uid);
272         if (!pw) {
273                 logit("You don't exist, go away!");
274                 exit(255);
275         }
276         /* Take a copy of the returned structure. */
277         pw = pwcopy(pw);
279         /*
280          * Set our umask to something reasonable, as some files are created
281          * with the default umask.  This will make them world-readable but
282          * writable only by the owner, which is ok for all files for which we
283          * don't set the modes explicitly.
284          */
285         umask(022);
287         /*
288          * Initialize option structure to indicate that no values have been
289          * set.
290          */
291         initialize_options(&options);
293         /* Parse command-line arguments. */
294         host = NULL;
295         use_syslog = 0;
296         argv0 = av[0];
298  again:
299         while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx"
300             "ACD:F:I:KL:MNO:PR:S:TVw:W:XYy")) != -1) {
301                 switch (opt) {
302                 case '1':
303                         options.protocol = SSH_PROTO_1;
304                         break;
305                 case '2':
306                         options.protocol = SSH_PROTO_2;
307                         break;
308                 case '4':
309                         options.address_family = AF_INET;
310                         break;
311                 case '6':
312                         options.address_family = AF_INET6;
313                         break;
314                 case 'n':
315                         stdin_null_flag = 1;
316                         break;
317                 case 'f':
318                         fork_after_authentication_flag = 1;
319                         stdin_null_flag = 1;
320                         break;
321                 case 'x':
322                         options.forward_x11 = 0;
323                         break;
324                 case 'X':
325                         options.forward_x11 = 1;
326                         break;
327                 case 'y':
328                         use_syslog = 1;
329                         break;
330                 case 'Y':
331                         options.forward_x11 = 1;
332                         options.forward_x11_trusted = 1;
333                         break;
334                 case 'g':
335                         options.gateway_ports = 1;
336                         break;
337                 case 'O':
338                         if (stdio_forward_host != NULL)
339                                 fatal("Cannot specify multiplexing "
340                                     "command with -W");
341                         else if (muxclient_command != 0)
342                                 fatal("Multiplexing command already specified");
343                         if (strcmp(optarg, "check") == 0)
344                                 muxclient_command = SSHMUX_COMMAND_ALIVE_CHECK;
345                         else if (strcmp(optarg, "forward") == 0)
346                                 muxclient_command = SSHMUX_COMMAND_FORWARD;
347                         else if (strcmp(optarg, "exit") == 0)
348                                 muxclient_command = SSHMUX_COMMAND_TERMINATE;
349                         else
350                                 fatal("Invalid multiplex command.");
351                         break;
352                 case 'P':       /* deprecated */
353                         options.use_privileged_port = 0;
354                         break;
355                 case 'a':
356                         options.forward_agent = 0;
357                         break;
358                 case 'A':
359                         options.forward_agent = 1;
360                         break;
361                 case 'k':
362                         options.gss_deleg_creds = 0;
363                         break;
364                 case 'K':
365                         options.gss_authentication = 1;
366                         options.gss_deleg_creds = 1;
367                         break;
368                 case 'i':
369                         if (stat(optarg, &st) < 0) {
370                                 fprintf(stderr, "Warning: Identity file %s "
371                                     "not accessible: %s.\n", optarg,
372                                     strerror(errno));
373                                 break;
374                         }
375                         if (options.num_identity_files >=
376                             SSH_MAX_IDENTITY_FILES)
377                                 fatal("Too many identity files specified "
378                                     "(max %d)", SSH_MAX_IDENTITY_FILES);
379                         options.identity_files[options.num_identity_files++] =
380                             xstrdup(optarg);
381                         break;
382                 case 'I':
383 #ifdef ENABLE_PKCS11
384                         options.pkcs11_provider = xstrdup(optarg);
385 #else
386                         fprintf(stderr, "no support for PKCS#11.\n");
387 #endif
388                         break;
389                 case 't':
390                         if (tty_flag)
391                                 force_tty_flag = 1;
392                         tty_flag = 1;
393                         break;
394                 case 'v':
395                         if (debug_flag == 0) {
396                                 debug_flag = 1;
397                                 options.log_level = SYSLOG_LEVEL_DEBUG1;
398                         } else {
399                                 if (options.log_level < SYSLOG_LEVEL_DEBUG3)
400                                         options.log_level++;
401                                 break;
402                         }
403                         /* FALLTHROUGH */
404                 case 'V':
405                         fprintf(stderr, "%s, %s\n",
406                             SSH_RELEASE, SSLeay_version(SSLEAY_VERSION));
407                         if (opt == 'V')
408                                 exit(0);
409                         break;
410                 case 'w':
411                         if (options.tun_open == -1)
412                                 options.tun_open = SSH_TUNMODE_DEFAULT;
413                         options.tun_local = a2tun(optarg, &options.tun_remote);
414                         if (options.tun_local == SSH_TUNID_ERR) {
415                                 fprintf(stderr,
416                                     "Bad tun device '%s'\n", optarg);
417                                 exit(255);
418                         }
419                         break;
420                 case 'W':
421                         if (stdio_forward_host != NULL)
422                                 fatal("stdio forward already specified");
423                         if (muxclient_command != 0)
424                                 fatal("Cannot specify stdio forward with -O");
425                         if (parse_forward(&fwd, optarg, 1, 0)) {
426                                 stdio_forward_host = fwd.listen_host;
427                                 stdio_forward_port = fwd.listen_port;
428                                 xfree(fwd.connect_host);
429                         } else {
430                                 fprintf(stderr,
431                                     "Bad stdio forwarding specification '%s'\n",
432                                     optarg);
433                                 exit(255);
434                         }
435                         no_tty_flag = 1;
436                         no_shell_flag = 1;
437                         options.clear_forwardings = 1;
438                         options.exit_on_forward_failure = 1;
439                         break;
440                 case 'q':
441                         options.log_level = SYSLOG_LEVEL_QUIET;
442                         break;
443                 case 'e':
444                         if (optarg[0] == '^' && optarg[2] == 0 &&
445                             (u_char) optarg[1] >= 64 &&
446                             (u_char) optarg[1] < 128)
447                                 options.escape_char = (u_char) optarg[1] & 31;
448                         else if (strlen(optarg) == 1)
449                                 options.escape_char = (u_char) optarg[0];
450                         else if (strcmp(optarg, "none") == 0)
451                                 options.escape_char = SSH_ESCAPECHAR_NONE;
452                         else {
453                                 fprintf(stderr, "Bad escape character '%s'.\n",
454                                     optarg);
455                                 exit(255);
456                         }
457                         break;
458                 case 'c':
459                         if (ciphers_valid(optarg)) {
460                                 /* SSH2 only */
461                                 options.ciphers = xstrdup(optarg);
462                                 options.cipher = SSH_CIPHER_INVALID;
463                         } else {
464                                 /* SSH1 only */
465                                 options.cipher = cipher_number(optarg);
466                                 if (options.cipher == -1) {
467                                         fprintf(stderr,
468                                             "Unknown cipher type '%s'\n",
469                                             optarg);
470                                         exit(255);
471                                 }
472                                 if (options.cipher == SSH_CIPHER_3DES)
473                                         options.ciphers = "3des-cbc";
474                                 else if (options.cipher == SSH_CIPHER_BLOWFISH)
475                                         options.ciphers = "blowfish-cbc";
476                                 else
477                                         options.ciphers = (char *)-1;
478                         }
479                         break;
480                 case 'm':
481                         if (mac_valid(optarg))
482                                 options.macs = xstrdup(optarg);
483                         else {
484                                 fprintf(stderr, "Unknown mac type '%s'\n",
485                                     optarg);
486                                 exit(255);
487                         }
488                         break;
489                 case 'M':
490                         if (options.control_master == SSHCTL_MASTER_YES)
491                                 options.control_master = SSHCTL_MASTER_ASK;
492                         else
493                                 options.control_master = SSHCTL_MASTER_YES;
494                         break;
495                 case 'p':
496                         options.port = a2port(optarg);
497                         if (options.port <= 0) {
498                                 fprintf(stderr, "Bad port '%s'\n", optarg);
499                                 exit(255);
500                         }
501                         break;
502                 case 'l':
503                         options.user = optarg;
504                         break;
506                 case 'L':
507                         if (parse_forward(&fwd, optarg, 0, 0))
508                                 add_local_forward(&options, &fwd);
509                         else {
510                                 fprintf(stderr,
511                                     "Bad local forwarding specification '%s'\n",
512                                     optarg);
513                                 exit(255);
514                         }
515                         break;
517                 case 'R':
518                         if (parse_forward(&fwd, optarg, 0, 1)) {
519                                 add_remote_forward(&options, &fwd);
520                         } else {
521                                 fprintf(stderr,
522                                     "Bad remote forwarding specification "
523                                     "'%s'\n", optarg);
524                                 exit(255);
525                         }
526                         break;
528                 case 'D':
529                         if (parse_forward(&fwd, optarg, 1, 0)) {
530                                 add_local_forward(&options, &fwd);
531                         } else {
532                                 fprintf(stderr,
533                                     "Bad dynamic forwarding specification "
534                                     "'%s'\n", optarg);
535                                 exit(255);
536                         }
537                         break;
539                 case 'C':
540                         options.compression = 1;
541                         break;
542                 case 'N':
543                         no_shell_flag = 1;
544                         no_tty_flag = 1;
545                         break;
546                 case 'T':
547                         no_tty_flag = 1;
548                         break;
549                 case 'o':
550                         dummy = 1;
551                         line = xstrdup(optarg);
552                         if (process_config_line(&options, host ? host : "",
553                             line, "command-line", 0, &dummy) != 0)
554                                 exit(255);
555                         xfree(line);
556                         break;
557                 case 's':
558                         subsystem_flag = 1;
559                         break;
560                 case 'S':
561                         if (options.control_path != NULL)
562                                 free(options.control_path);
563                         options.control_path = xstrdup(optarg);
564                         break;
565                 case 'b':
566                         options.bind_address = optarg;
567                         break;
568                 case 'F':
569                         config = optarg;
570                         break;
571                 default:
572                         usage();
573                 }
574         }
576         ac -= optind;
577         av += optind;
579         if (ac > 0 && !host) {
580                 if (strrchr(*av, '@')) {
581                         p = xstrdup(*av);
582                         cp = strrchr(p, '@');
583                         if (cp == NULL || cp == p)
584                                 usage();
585                         options.user = p;
586                         *cp = '\0';
587                         host = ++cp;
588                 } else
589                         host = *av;
590                 if (ac > 1) {
591                         optind = optreset = 1;
592                         goto again;
593                 }
594                 ac--, av++;
595         }
597         /* Check that we got a host name. */
598         if (!host)
599                 usage();
601         OpenSSL_add_all_algorithms();
602         ERR_load_crypto_strings();
604         /* Initialize the command to execute on remote host. */
605         buffer_init(&command);
607         /*
608          * Save the command to execute on the remote host in a buffer. There
609          * is no limit on the length of the command, except by the maximum
610          * packet size.  Also sets the tty flag if there is no command.
611          */
612         if (!ac) {
613                 /* No command specified - execute shell on a tty. */
614                 tty_flag = 1;
615                 if (subsystem_flag) {
616                         fprintf(stderr,
617                             "You must specify a subsystem to invoke.\n");
618                         usage();
619                 }
620         } else {
621                 /* A command has been specified.  Store it into the buffer. */
622                 for (i = 0; i < ac; i++) {
623                         if (i)
624                                 buffer_append(&command, " ", 1);
625                         buffer_append(&command, av[i], strlen(av[i]));
626                 }
627         }
629         /* Cannot fork to background if no command. */
630         if (fork_after_authentication_flag && buffer_len(&command) == 0 &&
631             !no_shell_flag)
632                 fatal("Cannot fork into background without a command "
633                     "to execute.");
635         /* Allocate a tty by default if no command specified. */
636         if (buffer_len(&command) == 0)
637                 tty_flag = 1;
639         /* Force no tty */
640         if (no_tty_flag || muxclient_command != 0)
641                 tty_flag = 0;
642         /* Do not allocate a tty if stdin is not a tty. */
643         if ((!isatty(fileno(stdin)) || stdin_null_flag) && !force_tty_flag) {
644                 if (tty_flag)
645                         logit("Pseudo-terminal will not be allocated because "
646                             "stdin is not a terminal.");
647                 tty_flag = 0;
648         }
650         /*
651          * Initialize "log" output.  Since we are the client all output
652          * actually goes to stderr.
653          */
654         log_init(argv0,
655             options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level,
656             SYSLOG_FACILITY_USER, !use_syslog);
658         /*
659          * Read per-user configuration file.  Ignore the system wide config
660          * file if the user specifies a config file on the command line.
661          */
662         if (config != NULL) {
663                 if (!read_config_file(config, host, &options, 0))
664                         fatal("Can't open user config file %.100s: "
665                             "%.100s", config, strerror(errno));
666         } else {
667                 r = snprintf(buf, sizeof buf, "%s/%s", pw->pw_dir,
668                     _PATH_SSH_USER_CONFFILE);
669                 if (r > 0 && (size_t)r < sizeof(buf))
670                         (void)read_config_file(buf, host, &options, 1);
672                 /* Read systemwide configuration file after use config. */
673                 (void)read_config_file(_PATH_HOST_CONFIG_FILE, host,
674                     &options, 0);
675         }
677         /* Fill configuration defaults. */
678         fill_default_options(&options);
680         channel_set_af(options.address_family);
682         /* reinit */
683         log_init(argv0, options.log_level, SYSLOG_FACILITY_USER, !use_syslog);
685         seed_rng();
687         if (options.user == NULL)
688                 options.user = xstrdup(pw->pw_name);
690         /* Get default port if port has not been set. */
691         if (options.port == 0) {
692                 sp = getservbyname(SSH_SERVICE_NAME, "tcp");
693                 options.port = sp ? ntohs(sp->s_port) : SSH_DEFAULT_PORT;
694         }
696         /* preserve host name given on command line for %n expansion */
697         host_arg = host;
698         if (options.hostname != NULL) {
699                 host = percent_expand(options.hostname,
700                     "h", host, (char *)NULL);
701         }
703         if (options.local_command != NULL) {
704                 char thishost[NI_MAXHOST];
706                 if (gethostname(thishost, sizeof(thishost)) == -1)
707                         fatal("gethostname: %s", strerror(errno));
708                 snprintf(buf, sizeof(buf), "%d", options.port);
709                 debug3("expanding LocalCommand: %s", options.local_command);
710                 cp = options.local_command;
711                 options.local_command = percent_expand(cp, "d", pw->pw_dir,
712                     "h", host, "l", thishost, "n", host_arg, "r", options.user,
713                     "p", buf, "u", pw->pw_name, (char *)NULL);
714                 debug3("expanded LocalCommand: %s", options.local_command);
715                 xfree(cp);
716         }
718         /* force lowercase for hostkey matching */
719         if (options.host_key_alias != NULL) {
720                 for (p = options.host_key_alias; *p; p++)
721                         if (isupper(*p))
722                                 *p = (char)tolower(*p);
723         }
725         if (options.proxy_command != NULL &&
726             strcmp(options.proxy_command, "none") == 0) {
727                 xfree(options.proxy_command);
728                 options.proxy_command = NULL;
729         }
730         if (options.control_path != NULL &&
731             strcmp(options.control_path, "none") == 0) {
732                 xfree(options.control_path);
733                 options.control_path = NULL;
734         }
736         if (options.control_path != NULL) {
737                 char thishost[NI_MAXHOST];
739                 if (gethostname(thishost, sizeof(thishost)) == -1)
740                         fatal("gethostname: %s", strerror(errno));
741                 snprintf(buf, sizeof(buf), "%d", options.port);
742                 cp = tilde_expand_filename(options.control_path,
743                     original_real_uid);
744                 xfree(options.control_path);
745                 options.control_path = percent_expand(cp, "p", buf, "h", host,
746                     "r", options.user, "l", thishost, (char *)NULL);
747                 xfree(cp);
748         }
749         if (muxclient_command != 0 && options.control_path == NULL)
750                 fatal("No ControlPath specified for \"-O\" command");
751         if (options.control_path != NULL)
752                 muxclient(options.control_path);
754         timeout_ms = options.connection_timeout * 1000;
756         /* Open a connection to the remote host. */
757         if (ssh_connect(host, &hostaddr, options.port,
758             options.address_family, options.connection_attempts, &timeout_ms,
759             options.tcp_keep_alive, 
760 #ifdef HAVE_CYGWIN
761             options.use_privileged_port,
762 #else
763             original_effective_uid == 0 && options.use_privileged_port,
764 #endif
765             options.proxy_command) != 0)
766                 exit(255);
768         if (timeout_ms > 0)
769                 debug3("timeout: %d ms remain after connect", timeout_ms);
771         /*
772          * If we successfully made the connection, load the host private key
773          * in case we will need it later for combined rsa-rhosts
774          * authentication. This must be done before releasing extra
775          * privileges, because the file is only readable by root.
776          * If we cannot access the private keys, load the public keys
777          * instead and try to execute the ssh-keysign helper instead.
778          */
779         sensitive_data.nkeys = 0;
780         sensitive_data.keys = NULL;
781         sensitive_data.external_keysign = 0;
782         if (options.rhosts_rsa_authentication ||
783             options.hostbased_authentication) {
784                 sensitive_data.nkeys = 7;
785                 sensitive_data.keys = xcalloc(sensitive_data.nkeys,
786                     sizeof(Key));
787                 for (i = 0; i < sensitive_data.nkeys; i++)
788                         sensitive_data.keys[i] = NULL;
790                 PRIV_START;
791                 sensitive_data.keys[0] = key_load_private_type(KEY_RSA1,
792                     _PATH_HOST_KEY_FILE, "", NULL, NULL);
793                 sensitive_data.keys[1] = key_load_private_cert(KEY_DSA,
794                     _PATH_HOST_DSA_KEY_FILE, "", NULL);
795 #ifdef OPENSSL_HAS_ECC
796                 sensitive_data.keys[2] = key_load_private_cert(KEY_ECDSA,
797                     _PATH_HOST_ECDSA_KEY_FILE, "", NULL);
798 #endif
799                 sensitive_data.keys[3] = key_load_private_cert(KEY_RSA,
800                     _PATH_HOST_RSA_KEY_FILE, "", NULL);
801                 sensitive_data.keys[4] = key_load_private_type(KEY_DSA,
802                     _PATH_HOST_DSA_KEY_FILE, "", NULL, NULL);
803 #ifdef OPENSSL_HAS_ECC
804                 sensitive_data.keys[5] = key_load_private_type(KEY_ECDSA,
805                     _PATH_HOST_ECDSA_KEY_FILE, "", NULL, NULL);
806 #endif
807                 sensitive_data.keys[6] = key_load_private_type(KEY_RSA,
808                     _PATH_HOST_RSA_KEY_FILE, "", NULL, NULL);
809                 PRIV_END;
811                 if (options.hostbased_authentication == 1 &&
812                     sensitive_data.keys[0] == NULL &&
813                     sensitive_data.keys[4] == NULL &&
814                     sensitive_data.keys[5] == NULL &&
815                     sensitive_data.keys[6] == NULL) {
816                         sensitive_data.keys[1] = key_load_cert(
817                             _PATH_HOST_DSA_KEY_FILE);
818 #ifdef OPENSSL_HAS_ECC
819                         sensitive_data.keys[2] = key_load_cert(
820                             _PATH_HOST_ECDSA_KEY_FILE);
821 #endif
822                         sensitive_data.keys[3] = key_load_cert(
823                             _PATH_HOST_RSA_KEY_FILE);
824                         sensitive_data.keys[4] = key_load_public(
825                             _PATH_HOST_DSA_KEY_FILE, NULL);
826 #ifdef OPENSSL_HAS_ECC
827                         sensitive_data.keys[5] = key_load_public(
828                             _PATH_HOST_ECDSA_KEY_FILE, NULL);
829 #endif
830                         sensitive_data.keys[6] = key_load_public(
831                             _PATH_HOST_RSA_KEY_FILE, NULL);
832                         sensitive_data.external_keysign = 1;
833                 }
834         }
835         /*
836          * Get rid of any extra privileges that we may have.  We will no
837          * longer need them.  Also, extra privileges could make it very hard
838          * to read identity files and other non-world-readable files from the
839          * user's home directory if it happens to be on a NFS volume where
840          * root is mapped to nobody.
841          */
842         if (original_effective_uid == 0) {
843                 PRIV_START;
844                 permanently_set_uid(pw);
845         }
847         /*
848          * Now that we are back to our own permissions, create ~/.ssh
849          * directory if it doesn't already exist.
850          */
851         r = snprintf(buf, sizeof buf, "%s%s%s", pw->pw_dir,
852             strcmp(pw->pw_dir, "/") ? "/" : "", _PATH_SSH_USER_DIR);
853         if (r > 0 && (size_t)r < sizeof(buf) && stat(buf, &st) < 0) {
854 #ifdef WITH_SELINUX
855                 ssh_selinux_setfscreatecon(buf);
856 #endif
857                 if (mkdir(buf, 0700) < 0)
858                         error("Could not create directory '%.200s'.", buf);
859 #ifdef WITH_SELINUX
860                 ssh_selinux_setfscreatecon(NULL);
861 #endif
862         }
863         /* load options.identity_files */
864         load_public_identity_files();
866         /* Expand ~ in known host file names. */
867         /* XXX mem-leaks: */
868         options.system_hostfile =
869             tilde_expand_filename(options.system_hostfile, original_real_uid);
870         options.user_hostfile =
871             tilde_expand_filename(options.user_hostfile, original_real_uid);
872         options.system_hostfile2 =
873             tilde_expand_filename(options.system_hostfile2, original_real_uid);
874         options.user_hostfile2 =
875             tilde_expand_filename(options.user_hostfile2, original_real_uid);
877         signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */
878         signal(SIGCHLD, main_sigchld_handler);
880         /* Log into the remote system.  Never returns if the login fails. */
881         ssh_login(&sensitive_data, host, (struct sockaddr *)&hostaddr,
882             options.port, pw, timeout_ms);
884         if (packet_connection_is_on_socket()) {
885                 verbose("Authenticated to %s ([%s]:%d).", host,
886                     get_remote_ipaddr(), get_remote_port());
887         } else {
888                 verbose("Authenticated to %s (via proxy).", host);
889         }
891         /* We no longer need the private host keys.  Clear them now. */
892         if (sensitive_data.nkeys != 0) {
893                 for (i = 0; i < sensitive_data.nkeys; i++) {
894                         if (sensitive_data.keys[i] != NULL) {
895                                 /* Destroys contents safely */
896                                 debug3("clear hostkey %d", i);
897                                 key_free(sensitive_data.keys[i]);
898                                 sensitive_data.keys[i] = NULL;
899                         }
900                 }
901                 xfree(sensitive_data.keys);
902         }
903         for (i = 0; i < options.num_identity_files; i++) {
904                 if (options.identity_files[i]) {
905                         xfree(options.identity_files[i]);
906                         options.identity_files[i] = NULL;
907                 }
908                 if (options.identity_keys[i]) {
909                         key_free(options.identity_keys[i]);
910                         options.identity_keys[i] = NULL;
911                 }
912         }
914         exit_status = compat20 ? ssh_session2() : ssh_session();
915         packet_close();
917         if (options.control_path != NULL && muxserver_sock != -1)
918                 unlink(options.control_path);
920         /* Kill ProxyCommand if it is running. */
921         ssh_kill_proxy_command();
923         return exit_status;
926 static void
927 control_persist_detach(void)
929         pid_t pid;
930         int devnull;
932         debug("%s: backgrounding master process", __func__);
934         /*
935          * master (current process) into the background, and make the
936          * foreground process a client of the backgrounded master.
937          */
938         switch ((pid = fork())) {
939         case -1:
940                 fatal("%s: fork: %s", __func__, strerror(errno));
941         case 0:
942                 /* Child: master process continues mainloop */
943                 break;
944         default:
945                 /* Parent: set up mux slave to connect to backgrounded master */
946                 debug2("%s: background process is %ld", __func__, (long)pid);
947                 stdin_null_flag = ostdin_null_flag;
948                 no_shell_flag = ono_shell_flag;
949                 no_tty_flag = ono_tty_flag;
950                 tty_flag = otty_flag;
951                 close(muxserver_sock);
952                 muxserver_sock = -1;
953                 options.control_master = SSHCTL_MASTER_NO;
954                 muxclient(options.control_path);
955                 /* muxclient() doesn't return on success. */
956                 fatal("Failed to connect to new control master");
957         }
958         if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1) {
959                 error("%s: open(\"/dev/null\"): %s", __func__,
960                     strerror(errno));
961         } else {
962                 if (dup2(devnull, STDIN_FILENO) == -1 ||
963                     dup2(devnull, STDOUT_FILENO) == -1)
964                         error("%s: dup2: %s", __func__, strerror(errno));
965                 if (devnull > STDERR_FILENO)
966                         close(devnull);
967         }
970 /* Do fork() after authentication. Used by "ssh -f" */
971 static void
972 fork_postauth(void)
974         if (need_controlpersist_detach)
975                 control_persist_detach();
976         debug("forking to background");
977         fork_after_authentication_flag = 0;
978         if (daemon(1, 1) < 0)
979                 fatal("daemon() failed: %.200s", strerror(errno));
982 /* Callback for remote forward global requests */
983 static void
984 ssh_confirm_remote_forward(int type, u_int32_t seq, void *ctxt)
986         Forward *rfwd = (Forward *)ctxt;
988         /* XXX verbose() on failure? */
989         debug("remote forward %s for: listen %d, connect %s:%d",
990             type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure",
991             rfwd->listen_port, rfwd->connect_host, rfwd->connect_port);
992         if (type == SSH2_MSG_REQUEST_SUCCESS && rfwd->listen_port == 0) {
993                 rfwd->allocated_port = packet_get_int();
994                 logit("Allocated port %u for remote forward to %s:%d",
995                     rfwd->allocated_port,
996                     rfwd->connect_host, rfwd->connect_port);
997         }
998         
999         if (type == SSH2_MSG_REQUEST_FAILURE) {
1000                 if (options.exit_on_forward_failure)
1001                         fatal("Error: remote port forwarding failed for "
1002                             "listen port %d", rfwd->listen_port);
1003                 else
1004                         logit("Warning: remote port forwarding failed for "
1005                             "listen port %d", rfwd->listen_port);
1006         }
1007         if (++remote_forward_confirms_received == options.num_remote_forwards) {
1008                 debug("All remote forwarding requests processed");
1009                 if (fork_after_authentication_flag)
1010                         fork_postauth();
1011         }
1014 static void
1015 client_cleanup_stdio_fwd(int id, void *arg)
1017         debug("stdio forwarding: done");
1018         cleanup_exit(0);
1021 static int
1022 client_setup_stdio_fwd(const char *host_to_connect, u_short port_to_connect)
1024         Channel *c;
1025         int in, out;
1027         debug3("client_setup_stdio_fwd %s:%d", host_to_connect,
1028             port_to_connect);
1030         in = dup(STDIN_FILENO);
1031         out = dup(STDOUT_FILENO);
1032         if (in < 0 || out < 0)
1033                 fatal("channel_connect_stdio_fwd: dup() in/out failed");
1035         if ((c = channel_connect_stdio_fwd(host_to_connect, port_to_connect,
1036             in, out)) == NULL)
1037                 return 0;
1038         channel_register_cleanup(c->self, client_cleanup_stdio_fwd, 0);
1039         return 1;
1042 static void
1043 ssh_init_forwarding(void)
1045         int success = 0;
1046         int i;
1048         if (stdio_forward_host != NULL) {
1049                 if (!compat20) {
1050                         fatal("stdio forwarding require Protocol 2");
1051                 }
1052                 if (!client_setup_stdio_fwd(stdio_forward_host,
1053                     stdio_forward_port))
1054                         fatal("Failed to connect in stdio forward mode.");
1055         }
1057         /* Initiate local TCP/IP port forwardings. */
1058         for (i = 0; i < options.num_local_forwards; i++) {
1059                 debug("Local connections to %.200s:%d forwarded to remote "
1060                     "address %.200s:%d",
1061                     (options.local_forwards[i].listen_host == NULL) ?
1062                     (options.gateway_ports ? "*" : "LOCALHOST") :
1063                     options.local_forwards[i].listen_host,
1064                     options.local_forwards[i].listen_port,
1065                     options.local_forwards[i].connect_host,
1066                     options.local_forwards[i].connect_port);
1067                 success += channel_setup_local_fwd_listener(
1068                     options.local_forwards[i].listen_host,
1069                     options.local_forwards[i].listen_port,
1070                     options.local_forwards[i].connect_host,
1071                     options.local_forwards[i].connect_port,
1072                     options.gateway_ports);
1073         }
1074         if (i > 0 && success != i && options.exit_on_forward_failure)
1075                 fatal("Could not request local forwarding.");
1076         if (i > 0 && success == 0)
1077                 error("Could not request local forwarding.");
1079         /* Initiate remote TCP/IP port forwardings. */
1080         for (i = 0; i < options.num_remote_forwards; i++) {
1081                 debug("Remote connections from %.200s:%d forwarded to "
1082                     "local address %.200s:%d",
1083                     (options.remote_forwards[i].listen_host == NULL) ?
1084                     "LOCALHOST" : options.remote_forwards[i].listen_host,
1085                     options.remote_forwards[i].listen_port,
1086                     options.remote_forwards[i].connect_host,
1087                     options.remote_forwards[i].connect_port);
1088                 if (channel_request_remote_forwarding(
1089                     options.remote_forwards[i].listen_host,
1090                     options.remote_forwards[i].listen_port,
1091                     options.remote_forwards[i].connect_host,
1092                     options.remote_forwards[i].connect_port) < 0) {
1093                         if (options.exit_on_forward_failure)
1094                                 fatal("Could not request remote forwarding.");
1095                         else
1096                                 logit("Warning: Could not request remote "
1097                                     "forwarding.");
1098                 }
1099                 client_register_global_confirm(ssh_confirm_remote_forward,
1100                     &options.remote_forwards[i]);
1101         }
1103         /* Initiate tunnel forwarding. */
1104         if (options.tun_open != SSH_TUNMODE_NO) {
1105                 if (client_request_tun_fwd(options.tun_open,
1106                     options.tun_local, options.tun_remote) == -1) {
1107                         if (options.exit_on_forward_failure)
1108                                 fatal("Could not request tunnel forwarding.");
1109                         else
1110                                 error("Could not request tunnel forwarding.");
1111                 }
1112         }                       
1115 static void
1116 check_agent_present(void)
1118         if (options.forward_agent) {
1119                 /* Clear agent forwarding if we don't have an agent. */
1120                 if (!ssh_agent_present())
1121                         options.forward_agent = 0;
1122         }
1125 static int
1126 ssh_session(void)
1128         int type;
1129         int interactive = 0;
1130         int have_tty = 0;
1131         struct winsize ws;
1132         char *cp;
1133         const char *display;
1135         /* Enable compression if requested. */
1136         if (options.compression) {
1137                 debug("Requesting compression at level %d.",
1138                     options.compression_level);
1140                 if (options.compression_level < 1 ||
1141                     options.compression_level > 9)
1142                         fatal("Compression level must be from 1 (fast) to "
1143                             "9 (slow, best).");
1145                 /* Send the request. */
1146                 packet_start(SSH_CMSG_REQUEST_COMPRESSION);
1147                 packet_put_int(options.compression_level);
1148                 packet_send();
1149                 packet_write_wait();
1150                 type = packet_read();
1151                 if (type == SSH_SMSG_SUCCESS)
1152                         packet_start_compression(options.compression_level);
1153                 else if (type == SSH_SMSG_FAILURE)
1154                         logit("Warning: Remote host refused compression.");
1155                 else
1156                         packet_disconnect("Protocol error waiting for "
1157                             "compression response.");
1158         }
1159         /* Allocate a pseudo tty if appropriate. */
1160         if (tty_flag) {
1161                 debug("Requesting pty.");
1163                 /* Start the packet. */
1164                 packet_start(SSH_CMSG_REQUEST_PTY);
1166                 /* Store TERM in the packet.  There is no limit on the
1167                    length of the string. */
1168                 cp = getenv("TERM");
1169                 if (!cp)
1170                         cp = "";
1171                 packet_put_cstring(cp);
1173                 /* Store window size in the packet. */
1174                 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
1175                         memset(&ws, 0, sizeof(ws));
1176                 packet_put_int((u_int)ws.ws_row);
1177                 packet_put_int((u_int)ws.ws_col);
1178                 packet_put_int((u_int)ws.ws_xpixel);
1179                 packet_put_int((u_int)ws.ws_ypixel);
1181                 /* Store tty modes in the packet. */
1182                 tty_make_modes(fileno(stdin), NULL);
1184                 /* Send the packet, and wait for it to leave. */
1185                 packet_send();
1186                 packet_write_wait();
1188                 /* Read response from the server. */
1189                 type = packet_read();
1190                 if (type == SSH_SMSG_SUCCESS) {
1191                         interactive = 1;
1192                         have_tty = 1;
1193                 } else if (type == SSH_SMSG_FAILURE)
1194                         logit("Warning: Remote host failed or refused to "
1195                             "allocate a pseudo tty.");
1196                 else
1197                         packet_disconnect("Protocol error waiting for pty "
1198                             "request response.");
1199         }
1200         /* Request X11 forwarding if enabled and DISPLAY is set. */
1201         display = getenv("DISPLAY");
1202         if (options.forward_x11 && display != NULL) {
1203                 char *proto, *data;
1204                 /* Get reasonable local authentication information. */
1205                 client_x11_get_proto(display, options.xauth_location,
1206                     options.forward_x11_trusted, 
1207                     options.forward_x11_timeout,
1208                     &proto, &data);
1209                 /* Request forwarding with authentication spoofing. */
1210                 debug("Requesting X11 forwarding with authentication "
1211                     "spoofing.");
1212                 x11_request_forwarding_with_spoofing(0, display, proto, data);
1214                 /* Read response from the server. */
1215                 type = packet_read();
1216                 if (type == SSH_SMSG_SUCCESS) {
1217                         interactive = 1;
1218                 } else if (type == SSH_SMSG_FAILURE) {
1219                         logit("Warning: Remote host denied X11 forwarding.");
1220                 } else {
1221                         packet_disconnect("Protocol error waiting for X11 "
1222                             "forwarding");
1223                 }
1224         }
1225         /* Tell the packet module whether this is an interactive session. */
1226         packet_set_interactive(interactive,
1227             options.ip_qos_interactive, options.ip_qos_bulk);
1229         /* Request authentication agent forwarding if appropriate. */
1230         check_agent_present();
1232         if (options.forward_agent) {
1233                 debug("Requesting authentication agent forwarding.");
1234                 auth_request_forwarding();
1236                 /* Read response from the server. */
1237                 type = packet_read();
1238                 packet_check_eom();
1239                 if (type != SSH_SMSG_SUCCESS)
1240                         logit("Warning: Remote host denied authentication agent forwarding.");
1241         }
1243         /* Initiate port forwardings. */
1244         ssh_init_forwarding();
1246         /* Execute a local command */
1247         if (options.local_command != NULL &&
1248             options.permit_local_command)
1249                 ssh_local_cmd(options.local_command);
1251         /*
1252          * If requested and we are not interested in replies to remote
1253          * forwarding requests, then let ssh continue in the background.
1254          */
1255         if (fork_after_authentication_flag) {
1256                 if (options.exit_on_forward_failure &&
1257                     options.num_remote_forwards > 0) {
1258                         debug("deferring postauth fork until remote forward "
1259                             "confirmation received");
1260                 } else
1261                         fork_postauth();
1262         }
1264         /*
1265          * If a command was specified on the command line, execute the
1266          * command now. Otherwise request the server to start a shell.
1267          */
1268         if (buffer_len(&command) > 0) {
1269                 int len = buffer_len(&command);
1270                 if (len > 900)
1271                         len = 900;
1272                 debug("Sending command: %.*s", len,
1273                     (u_char *)buffer_ptr(&command));
1274                 packet_start(SSH_CMSG_EXEC_CMD);
1275                 packet_put_string(buffer_ptr(&command), buffer_len(&command));
1276                 packet_send();
1277                 packet_write_wait();
1278         } else {
1279                 debug("Requesting shell.");
1280                 packet_start(SSH_CMSG_EXEC_SHELL);
1281                 packet_send();
1282                 packet_write_wait();
1283         }
1285         /* Enter the interactive session. */
1286         return client_loop(have_tty, tty_flag ?
1287             options.escape_char : SSH_ESCAPECHAR_NONE, 0);
1290 /* request pty/x11/agent/tcpfwd/shell for channel */
1291 static void
1292 ssh_session2_setup(int id, int success, void *arg)
1294         extern char **environ;
1295         const char *display;
1296         int interactive = tty_flag;
1298         if (!success)
1299                 return; /* No need for error message, channels code sens one */
1301         display = getenv("DISPLAY");
1302         if (options.forward_x11 && display != NULL) {
1303                 char *proto, *data;
1304                 /* Get reasonable local authentication information. */
1305                 client_x11_get_proto(display, options.xauth_location,
1306                     options.forward_x11_trusted,
1307                     options.forward_x11_timeout, &proto, &data);
1308                 /* Request forwarding with authentication spoofing. */
1309                 debug("Requesting X11 forwarding with authentication "
1310                     "spoofing.");
1311                 x11_request_forwarding_with_spoofing(id, display, proto, data);
1312                 interactive = 1;
1313                 /* XXX wait for reply */
1314         }
1316         check_agent_present();
1317         if (options.forward_agent) {
1318                 debug("Requesting authentication agent forwarding.");
1319                 channel_request_start(id, "auth-agent-req@openssh.com", 0);
1320                 packet_send();
1321         }
1323         client_session2_setup(id, tty_flag, subsystem_flag, getenv("TERM"),
1324             NULL, fileno(stdin), &command, environ);
1327 /* open new channel for a session */
1328 static int
1329 ssh_session2_open(void)
1331         Channel *c;
1332         int window, packetmax, in, out, err;
1334         if (stdin_null_flag) {
1335                 in = open(_PATH_DEVNULL, O_RDONLY);
1336         } else {
1337                 in = dup(STDIN_FILENO);
1338         }
1339         out = dup(STDOUT_FILENO);
1340         err = dup(STDERR_FILENO);
1342         if (in < 0 || out < 0 || err < 0)
1343                 fatal("dup() in/out/err failed");
1345         /* enable nonblocking unless tty */
1346         if (!isatty(in))
1347                 set_nonblock(in);
1348         if (!isatty(out))
1349                 set_nonblock(out);
1350         if (!isatty(err))
1351                 set_nonblock(err);
1353         window = CHAN_SES_WINDOW_DEFAULT;
1354         packetmax = CHAN_SES_PACKET_DEFAULT;
1355         if (tty_flag) {
1356                 window >>= 1;
1357                 packetmax >>= 1;
1358         }
1359         c = channel_new(
1360             "session", SSH_CHANNEL_OPENING, in, out, err,
1361             window, packetmax, CHAN_EXTENDED_WRITE,
1362             "client-session", /*nonblock*/0);
1364         debug3("ssh_session2_open: channel_new: %d", c->self);
1366         channel_send_open(c->self);
1367         if (!no_shell_flag)
1368                 channel_register_open_confirm(c->self,
1369                     ssh_session2_setup, NULL);
1371         return c->self;
1374 static int
1375 ssh_session2(void)
1377         int id = -1;
1379         /* XXX should be pre-session */
1380         ssh_init_forwarding();
1382         /* Start listening for multiplex clients */
1383         muxserver_listen();
1385         /*
1386          * If we are in control persist mode, then prepare to background
1387          * ourselves and have a foreground client attach as a control
1388          * slave. NB. we must save copies of the flags that we override for
1389          * the backgrounding, since we defer attachment of the slave until
1390          * after the connection is fully established (in particular,
1391          * async rfwd replies have been received for ExitOnForwardFailure).
1392          */
1393         if (options.control_persist && muxserver_sock != -1) {
1394                 ostdin_null_flag = stdin_null_flag;
1395                 ono_shell_flag = no_shell_flag;
1396                 ono_tty_flag = no_tty_flag;
1397                 otty_flag = tty_flag;
1398                 stdin_null_flag = 1;
1399                 no_shell_flag = 1;
1400                 no_tty_flag = 1;
1401                 tty_flag = 0;
1402                 if (!fork_after_authentication_flag)
1403                         need_controlpersist_detach = 1;
1404                 fork_after_authentication_flag = 1;
1405         }
1407         if (!no_shell_flag || (datafellows & SSH_BUG_DUMMYCHAN))
1408                 id = ssh_session2_open();
1410         /* If we don't expect to open a new session, then disallow it */
1411         if (options.control_master == SSHCTL_MASTER_NO &&
1412             (datafellows & SSH_NEW_OPENSSH)) {
1413                 debug("Requesting no-more-sessions@openssh.com");
1414                 packet_start(SSH2_MSG_GLOBAL_REQUEST);
1415                 packet_put_cstring("no-more-sessions@openssh.com");
1416                 packet_put_char(0);
1417                 packet_send();
1418         }
1420         /* Execute a local command */
1421         if (options.local_command != NULL &&
1422             options.permit_local_command)
1423                 ssh_local_cmd(options.local_command);
1425         /*
1426          * If requested and we are not interested in replies to remote
1427          * forwarding requests, then let ssh continue in the background.
1428          */
1429         if (fork_after_authentication_flag) {
1430                 if (options.exit_on_forward_failure &&
1431                     options.num_remote_forwards > 0) {
1432                         debug("deferring postauth fork until remote forward "
1433                             "confirmation received");
1434                 } else
1435                         fork_postauth();
1436         }
1438         if (options.use_roaming)
1439                 request_roaming();
1441         return client_loop(tty_flag, tty_flag ?
1442             options.escape_char : SSH_ESCAPECHAR_NONE, id);
1445 static void
1446 load_public_identity_files(void)
1448         char *filename, *cp, thishost[NI_MAXHOST];
1449         char *pwdir = NULL, *pwname = NULL;
1450         int i = 0;
1451         Key *public;
1452         struct passwd *pw;
1453         u_int n_ids;
1454         char *identity_files[SSH_MAX_IDENTITY_FILES];
1455         Key *identity_keys[SSH_MAX_IDENTITY_FILES];
1456 #ifdef ENABLE_PKCS11
1457         Key **keys;
1458         int nkeys;
1459 #endif /* PKCS11 */
1461         n_ids = 0;
1462         bzero(identity_files, sizeof(identity_files));
1463         bzero(identity_keys, sizeof(identity_keys));
1465 #ifdef ENABLE_PKCS11
1466         if (options.pkcs11_provider != NULL &&
1467             options.num_identity_files < SSH_MAX_IDENTITY_FILES &&
1468             (pkcs11_init(!options.batch_mode) == 0) &&
1469             (nkeys = pkcs11_add_provider(options.pkcs11_provider, NULL,
1470             &keys)) > 0) {
1471                 for (i = 0; i < nkeys; i++) {
1472                         if (n_ids >= SSH_MAX_IDENTITY_FILES) {
1473                                 key_free(keys[i]);
1474                                 continue;
1475                         }
1476                         identity_keys[n_ids] = keys[i];
1477                         identity_files[n_ids] =
1478                             xstrdup(options.pkcs11_provider); /* XXX */
1479                         n_ids++;
1480                 }
1481                 xfree(keys);
1482         }
1483 #endif /* ENABLE_PKCS11 */
1484         if ((pw = getpwuid(original_real_uid)) == NULL)
1485                 fatal("load_public_identity_files: getpwuid failed");
1486         pwname = xstrdup(pw->pw_name);
1487         pwdir = xstrdup(pw->pw_dir);
1488         if (gethostname(thishost, sizeof(thishost)) == -1)
1489                 fatal("load_public_identity_files: gethostname: %s",
1490                     strerror(errno));
1491         for (i = 0; i < options.num_identity_files; i++) {
1492                 if (n_ids >= SSH_MAX_IDENTITY_FILES) {
1493                         xfree(options.identity_files[i]);
1494                         continue;
1495                 }
1496                 cp = tilde_expand_filename(options.identity_files[i],
1497                     original_real_uid);
1498                 filename = percent_expand(cp, "d", pwdir,
1499                     "u", pwname, "l", thishost, "h", host,
1500                     "r", options.user, (char *)NULL);
1501                 xfree(cp);
1502                 public = key_load_public(filename, NULL);
1503                 debug("identity file %s type %d", filename,
1504                     public ? public->type : -1);
1505                 xfree(options.identity_files[i]);
1506                 identity_files[n_ids] = filename;
1507                 identity_keys[n_ids] = public;
1509                 if (++n_ids >= SSH_MAX_IDENTITY_FILES)
1510                         continue;
1512                 /* Try to add the certificate variant too */
1513                 xasprintf(&cp, "%s-cert", filename);
1514                 public = key_load_public(cp, NULL);
1515                 debug("identity file %s type %d", cp,
1516                     public ? public->type : -1);
1517                 if (public == NULL) {
1518                         xfree(cp);
1519                         continue;
1520                 }
1521                 if (!key_is_cert(public)) {
1522                         debug("%s: key %s type %s is not a certificate",
1523                             __func__, cp, key_type(public));
1524                         key_free(public);
1525                         xfree(cp);
1526                         continue;
1527                 }
1528                 identity_keys[n_ids] = public;
1529                 /* point to the original path, most likely the private key */
1530                 identity_files[n_ids] = xstrdup(filename);
1531                 n_ids++;
1532         }
1533         options.num_identity_files = n_ids;
1534         memcpy(options.identity_files, identity_files, sizeof(identity_files));
1535         memcpy(options.identity_keys, identity_keys, sizeof(identity_keys));
1537         bzero(pwname, strlen(pwname));
1538         xfree(pwname);
1539         bzero(pwdir, strlen(pwdir));
1540         xfree(pwdir);
1543 static void
1544 main_sigchld_handler(int sig)
1546         int save_errno = errno;
1547         pid_t pid;
1548         int status;
1550         while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
1551             (pid < 0 && errno == EINTR))
1552                 ;
1554         signal(sig, main_sigchld_handler);
1555         errno = save_errno;