crypto/openssh/ssh.c

   1 /* $OpenBSD: ssh.c,v 1.445 2016/07/17 04:20:16 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 __RCSID("$FreeBSD$");
  45
  46 #include <sys/types.h>
  47 #ifdef HAVE_SYS_STAT_H
  48 # include <sys/stat.h>
  49 #endif
  50 #include <sys/resource.h>
  51 #include <sys/ioctl.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 #include <limits.h>
  71 #include <locale.h>
  72
  73 #include <netinet/in.h>
  74 #include <arpa/inet.h>
  75
  76 #ifdef WITH_OPENSSL
  77 #include <openssl/evp.h>
  78 #include <openssl/err.h>
  79 #endif
  80 #include "openbsd-compat/openssl-compat.h"
  81 #include "openbsd-compat/sys-queue.h"
  82
  83 #include "xmalloc.h"
  84 #include "ssh.h"
  85 #include "ssh1.h"
  86 #include "ssh2.h"
  87 #include "canohost.h"
  88 #include "compat.h"
  89 #include "cipher.h"
  90 #include "digest.h"
  91 #include "packet.h"
  92 #include "buffer.h"
  93 #include "channels.h"
  94 #include "key.h"
  95 #include "authfd.h"
  96 #include "authfile.h"
  97 #include "pathnames.h"
  98 #include "dispatch.h"
  99 #include "clientloop.h"
 100 #include "log.h"
 101 #include "misc.h"
 102 #include "readconf.h"
 103 #include "sshconnect.h"
 104 #include "kex.h"
 105 #include "mac.h"
 106 #include "sshpty.h"
 107 #include "match.h"
 108 #include "msg.h"
 109 #include "uidswap.h"
 110 #include "version.h"
 111 #include "ssherr.h"
 112 #include "myproposal.h"
 113
 114 #ifdef ENABLE_PKCS11
 115 #include "ssh-pkcs11.h"
 116 #endif
 117
 118 extern char *__progname;
 119
 120 /* Saves a copy of argv for setproctitle emulation */
 121 #ifndef HAVE_SETPROCTITLE
 122 static char **saved_av;
 123 #endif
 124
 125 /* Flag indicating whether debug mode is on.  May be set on the command line. */
 126 int debug_flag = 0;
 127
 128 /* Flag indicating whether a tty should be requested */
 129 int tty_flag = 0;
 130
 131 /* don't exec a shell */
 132 int no_shell_flag = 0;
 133
 134 /*
 135  * Flag indicating that nothing should be read from stdin.  This can be set
 136  * on the command line.
 137  */
 138 int stdin_null_flag = 0;
 139
 140 /*
 141  * Flag indicating that the current process should be backgrounded and
 142  * a new slave launched in the foreground for ControlPersist.
 143  */
 144 int need_controlpersist_detach = 0;
 145
 146 /* Copies of flags for ControlPersist foreground slave */
 147 int ostdin_null_flag, ono_shell_flag, otty_flag, orequest_tty;
 148
 149 /*
 150  * Flag indicating that ssh should fork after authentication.  This is useful
 151  * so that the passphrase can be entered manually, and then ssh goes to the
 152  * background.
 153  */
 154 int fork_after_authentication_flag = 0;
 155
 156 /*
 157  * General data structure for command line options and options configurable
 158  * in configuration files.  See readconf.h.
 159  */
 160 Options options;
 161
 162 /* optional user configfile */
 163 char *config = NULL;
 164
 165 /*
 166  * Name of the host we are connecting to.  This is the name given on the
 167  * command line, or the HostName specified for the user-supplied name in a
 168  * configuration file.
 169  */
 170 char *host;
 171
 172 /* socket address the host resolves to */
 173 struct sockaddr_storage hostaddr;
 174
 175 /* Private host keys. */
 176 Sensitive sensitive_data;
 177
 178 /* Original real UID. */
 179 uid_t original_real_uid;
 180 uid_t original_effective_uid;
 181
 182 /* command to be executed */
 183 Buffer command;
 184
 185 /* Should we execute a command or invoke a subsystem? */
 186 int subsystem_flag = 0;
 187
 188 /* # of replies received for global requests */
 189 static int remote_forward_confirms_received = 0;
 190
 191 /* mux.c */
 192 extern int muxserver_sock;
 193 extern u_int muxclient_command;
 194
 195 /* Prints a help message to the user.  This function never returns. */
 196
 197 static void
 198 usage(void)
 199 {
 200         fprintf(stderr,
 201 "usage: ssh [-1246AaCfGgKkMNnqsTtVvXxYy] [-b bind_address] [-c cipher_spec]\n"
 202 "           [-D [bind_address:]port] [-E log_file] [-e escape_char]\n"
 203 "           [-F configfile] [-I pkcs11] [-i identity_file]\n"
 204 "           [-J [user@]host[:port]] [-L address] [-l login_name] [-m mac_spec]\n"
 205 "           [-O ctl_cmd] [-o option] [-p port] [-Q query_option] [-R address]\n"
 206 "           [-S ctl_path] [-W host:port] [-w local_tun[:remote_tun]]\n"
 207 "           [user@]hostname [command]\n"
 208         );
 209         exit(255);
 210 }
 211
 212 static int ssh_session(void);
 213 static int ssh_session2(void);
 214 static void load_public_identity_files(void);
 215 static void main_sigchld_handler(int);
 216
 217 /* from muxclient.c */
 218 void muxclient(const char *);
 219 void muxserver_listen(void);
 220
 221 /* ~/ expand a list of paths. NB. assumes path[n] is heap-allocated. */
 222 static void
 223 tilde_expand_paths(char **paths, u_int num_paths)
 224 {
 225         u_int i;
 226         char *cp;
 227
 228         for (i = 0; i < num_paths; i++) {
 229                 cp = tilde_expand_filename(paths[i], original_real_uid);
 230                 free(paths[i]);
 231                 paths[i] = cp;
 232         }
 233 }
 234
 235 /*
 236  * Attempt to resolve a host name / port to a set of addresses and
 237  * optionally return any CNAMEs encountered along the way.
 238  * Returns NULL on failure.
 239  * NB. this function must operate with a options having undefined members.
 240  */
 241 static struct addrinfo *
 242 resolve_host(const char *name, int port, int logerr, char *cname, size_t clen)
 243 {
 244         char strport[NI_MAXSERV];
 245         struct addrinfo hints, *res;
 246         int gaierr, loglevel = SYSLOG_LEVEL_DEBUG1;
 247
 248         if (port <= 0)
 249                 port = default_ssh_port();
 250
 251         snprintf(strport, sizeof strport, "%d", port);
 252         memset(&hints, 0, sizeof(hints));
 253         hints.ai_family = options.address_family == -1 ?
 254             AF_UNSPEC : options.address_family;
 255         hints.ai_socktype = SOCK_STREAM;
 256         if (cname != NULL)
 257                 hints.ai_flags = AI_CANONNAME;
 258         if ((gaierr = getaddrinfo(name, strport, &hints, &res)) != 0) {
 259                 if (logerr || (gaierr != EAI_NONAME && gaierr != EAI_NODATA))
 260                         loglevel = SYSLOG_LEVEL_ERROR;
 261                 do_log2(loglevel, "%s: Could not resolve hostname %.100s: %s",
 262                     __progname, name, ssh_gai_strerror(gaierr));
 263                 return NULL;
 264         }
 265         if (cname != NULL && res->ai_canonname != NULL) {
 266                 if (strlcpy(cname, res->ai_canonname, clen) >= clen) {
 267                         error("%s: host \"%s\" cname \"%s\" too long (max %lu)",
 268                             __func__, name,  res->ai_canonname, (u_long)clen);
 269                         if (clen > 0)
 270                                 *cname = '\0';
 271                 }
 272         }
 273         return res;
 274 }
 275
 276 /*
 277  * Attempt to resolve a numeric host address / port to a single address.
 278  * Returns a canonical address string.
 279  * Returns NULL on failure.
 280  * NB. this function must operate with a options having undefined members.
 281  */
 282 static struct addrinfo *
 283 resolve_addr(const char *name, int port, char *caddr, size_t clen)
 284 {
 285         char addr[NI_MAXHOST], strport[NI_MAXSERV];
 286         struct addrinfo hints, *res;
 287         int gaierr;
 288
 289         if (port <= 0)
 290                 port = default_ssh_port();
 291         snprintf(strport, sizeof strport, "%u", port);
 292         memset(&hints, 0, sizeof(hints));
 293         hints.ai_family = options.address_family == -1 ?
 294             AF_UNSPEC : options.address_family;
 295         hints.ai_socktype = SOCK_STREAM;
 296         hints.ai_flags = AI_NUMERICHOST|AI_NUMERICSERV;
 297         if ((gaierr = getaddrinfo(name, strport, &hints, &res)) != 0) {
 298                 debug2("%s: could not resolve name %.100s as address: %s",
 299                     __func__, name, ssh_gai_strerror(gaierr));
 300                 return NULL;
 301         }
 302         if (res == NULL) {
 303                 debug("%s: getaddrinfo %.100s returned no addresses",
 304                  __func__, name);
 305                 return NULL;
 306         }
 307         if (res->ai_next != NULL) {
 308                 debug("%s: getaddrinfo %.100s returned multiple addresses",
 309                     __func__, name);
 310                 goto fail;
 311         }
 312         if ((gaierr = getnameinfo(res->ai_addr, res->ai_addrlen,
 313             addr, sizeof(addr), NULL, 0, NI_NUMERICHOST)) != 0) {
 314                 debug("%s: Could not format address for name %.100s: %s",
 315                     __func__, name, ssh_gai_strerror(gaierr));
 316                 goto fail;
 317         }
 318         if (strlcpy(caddr, addr, clen) >= clen) {
 319                 error("%s: host \"%s\" addr \"%s\" too long (max %lu)",
 320                     __func__, name,  addr, (u_long)clen);
 321                 if (clen > 0)
 322                         *caddr = '\0';
 323  fail:
 324                 freeaddrinfo(res);
 325                 return NULL;
 326         }
 327         return res;
 328 }
 329
 330 /*
 331  * Check whether the cname is a permitted replacement for the hostname
 332  * and perform the replacement if it is.
 333  * NB. this function must operate with a options having undefined members.
 334  */
 335 static int
 336 check_follow_cname(int direct, char **namep, const char *cname)
 337 {
 338         int i;
 339         struct allowed_cname *rule;
 340
 341         if (*cname == '\0' || options.num_permitted_cnames == 0 ||
 342             strcmp(*namep, cname) == 0)
 343                 return 0;
 344         if (options.canonicalize_hostname == SSH_CANONICALISE_NO)
 345                 return 0;
 346         /*
 347          * Don't attempt to canonicalize names that will be interpreted by
 348          * a proxy or jump host unless the user specifically requests so.
 349          */
 350         if (!direct &&
 351             options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS)
 352                 return 0;
 353         debug3("%s: check \"%s\" CNAME \"%s\"", __func__, *namep, cname);
 354         for (i = 0; i < options.num_permitted_cnames; i++) {
 355                 rule = options.permitted_cnames + i;
 356                 if (match_pattern_list(*namep, rule->source_list, 1) != 1 ||
 357                     match_pattern_list(cname, rule->target_list, 1) != 1)
 358                         continue;
 359                 verbose("Canonicalized DNS aliased hostname "
 360                     "\"%s\" => \"%s\"", *namep, cname);
 361                 free(*namep);
 362                 *namep = xstrdup(cname);
 363                 return 1;
 364         }
 365         return 0;
 366 }
 367
 368 /*
 369  * Attempt to resolve the supplied hostname after applying the user's
 370  * canonicalization rules. Returns the address list for the host or NULL
 371  * if no name was found after canonicalization.
 372  * NB. this function must operate with a options having undefined members.
 373  */
 374 static struct addrinfo *
 375 resolve_canonicalize(char **hostp, int port)
 376 {
 377         int i, direct, ndots;
 378         char *cp, *fullhost, newname[NI_MAXHOST];
 379         struct addrinfo *addrs;
 380
 381         if (options.canonicalize_hostname == SSH_CANONICALISE_NO)
 382                 return NULL;
 383
 384         /*
 385          * Don't attempt to canonicalize names that will be interpreted by
 386          * a proxy unless the user specifically requests so.
 387          */
 388         direct = option_clear_or_none(options.proxy_command) &&
 389             options.jump_host == NULL;
 390         if (!direct &&
 391             options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS)
 392                 return NULL;
 393
 394         /* Try numeric hostnames first */
 395         if ((addrs = resolve_addr(*hostp, port,
 396             newname, sizeof(newname))) != NULL) {
 397                 debug2("%s: hostname %.100s is address", __func__, *hostp);
 398                 if (strcasecmp(*hostp, newname) != 0) {
 399                         debug2("%s: canonicalised address \"%s\" => \"%s\"",
 400                             __func__, *hostp, newname);
 401                         free(*hostp);
 402                         *hostp = xstrdup(newname);
 403                 }
 404                 return addrs;
 405         }
 406
 407         /* If domain name is anchored, then resolve it now */
 408         if ((*hostp)[strlen(*hostp) - 1] == '.') {
 409                 debug3("%s: name is fully qualified", __func__);
 410                 fullhost = xstrdup(*hostp);
 411                 if ((addrs = resolve_host(fullhost, port, 0,
 412                     newname, sizeof(newname))) != NULL)
 413                         goto found;
 414                 free(fullhost);
 415                 goto notfound;
 416         }
 417
 418         /* Don't apply canonicalization to sufficiently-qualified hostnames */
 419         ndots = 0;
 420         for (cp = *hostp; *cp != '\0'; cp++) {
 421                 if (*cp == '.')
 422                         ndots++;
 423         }
 424         if (ndots > options.canonicalize_max_dots) {
 425                 debug3("%s: not canonicalizing hostname \"%s\" (max dots %d)",
 426                     __func__, *hostp, options.canonicalize_max_dots);
 427                 return NULL;
 428         }
 429         /* Attempt each supplied suffix */
 430         for (i = 0; i < options.num_canonical_domains; i++) {
 431                 *newname = '\0';
 432                 xasprintf(&fullhost, "%s.%s.", *hostp,
 433                     options.canonical_domains[i]);
 434                 debug3("%s: attempting \"%s\" => \"%s\"", __func__,
 435                     *hostp, fullhost);
 436                 if ((addrs = resolve_host(fullhost, port, 0,
 437                     newname, sizeof(newname))) == NULL) {
 438                         free(fullhost);
 439                         continue;
 440                 }
 441  found:
 442                 /* Remove trailing '.' */
 443                 fullhost[strlen(fullhost) - 1] = '\0';
 444                 /* Follow CNAME if requested */
 445                 if (!check_follow_cname(direct, &fullhost, newname)) {
 446                         debug("Canonicalized hostname \"%s\" => \"%s\"",
 447                             *hostp, fullhost);
 448                 }
 449                 free(*hostp);
 450                 *hostp = fullhost;
 451                 return addrs;
 452         }
 453  notfound:
 454         if (!options.canonicalize_fallback_local)
 455                 fatal("%s: Could not resolve host \"%s\"", __progname, *hostp);
 456         debug2("%s: host %s not found in any suffix", __func__, *hostp);
 457         return NULL;
 458 }
 459
 460 /*
 461  * Read per-user configuration file.  Ignore the system wide config
 462  * file if the user specifies a config file on the command line.
 463  */
 464 static void
 465 process_config_files(const char *host_arg, struct passwd *pw, int post_canon)
 466 {
 467         char buf[PATH_MAX];
 468         int r;
 469
 470         if (config != NULL) {
 471                 if (strcasecmp(config, "none") != 0 &&
 472                     !read_config_file(config, pw, host, host_arg, &options,
 473                     SSHCONF_USERCONF | (post_canon ? SSHCONF_POSTCANON : 0)))
 474                         fatal("Can't open user config file %.100s: "
 475                             "%.100s", config, strerror(errno));
 476         } else {
 477                 r = snprintf(buf, sizeof buf, "%s/%s", pw->pw_dir,
 478                     _PATH_SSH_USER_CONFFILE);
 479                 if (r > 0 && (size_t)r < sizeof(buf))
 480                         (void)read_config_file(buf, pw, host, host_arg,
 481                             &options, SSHCONF_CHECKPERM | SSHCONF_USERCONF |
 482                             (post_canon ? SSHCONF_POSTCANON : 0));
 483
 484                 /* Read systemwide configuration file after user config. */
 485                 (void)read_config_file(_PATH_HOST_CONFIG_FILE, pw,
 486                     host, host_arg, &options,
 487                     post_canon ? SSHCONF_POSTCANON : 0);
 488         }
 489 }
 490
 491 /* Rewrite the port number in an addrinfo list of addresses */
 492 static void
 493 set_addrinfo_port(struct addrinfo *addrs, int port)
 494 {
 495         struct addrinfo *addr;
 496
 497         for (addr = addrs; addr != NULL; addr = addr->ai_next) {
 498                 switch (addr->ai_family) {
 499                 case AF_INET:
 500                         ((struct sockaddr_in *)addr->ai_addr)->
 501                             sin_port = htons(port);
 502                         break;
 503                 case AF_INET6:
 504                         ((struct sockaddr_in6 *)addr->ai_addr)->
 505                             sin6_port = htons(port);
 506                         break;
 507                 }
 508         }
 509 }
 510
 511 /*
 512  * Main program for the ssh client.
 513  */
 514 int
 515 main(int ac, char **av)
 516 {
 517         struct ssh *ssh = NULL;
 518         int i, r, opt, exit_status, use_syslog, direct, config_test = 0;
 519         char *p, *cp, *line, *argv0, buf[PATH_MAX], *host_arg, *logfile;
 520         char thishost[NI_MAXHOST], shorthost[NI_MAXHOST], portstr[NI_MAXSERV];
 521         char cname[NI_MAXHOST], uidstr[32], *conn_hash_hex;
 522         struct stat st;
 523         struct passwd *pw;
 524         int timeout_ms;
 525         extern int optind, optreset;
 526         extern char *optarg;
 527         struct Forward fwd;
 528         struct addrinfo *addrs = NULL;
 529         struct ssh_digest_ctx *md;
 530         u_char conn_hash[SSH_DIGEST_MAX_LENGTH];
 531
 532         ssh_malloc_init();      /* must be called before any mallocs */
 533         /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
 534         sanitise_stdfd();
 535
 536         __progname = ssh_get_progname(av[0]);
 537
 538 #ifndef HAVE_SETPROCTITLE
 539         /* Prepare for later setproctitle emulation */
 540         /* Save argv so it isn't clobbered by setproctitle() emulation */
 541         saved_av = xcalloc(ac + 1, sizeof(*saved_av));
 542         for (i = 0; i < ac; i++)
 543                 saved_av[i] = xstrdup(av[i]);
 544         saved_av[i] = NULL;
 545         compat_init_setproctitle(ac, av);
 546         av = saved_av;
 547 #endif
 548
 549         /*
 550          * Discard other fds that are hanging around. These can cause problem
 551          * with backgrounded ssh processes started by ControlPersist.
 552          */
 553         closefrom(STDERR_FILENO + 1);
 554
 555         /*
 556          * Save the original real uid.  It will be needed later (uid-swapping
 557          * may clobber the real uid).
 558          */
 559         original_real_uid = getuid();
 560         original_effective_uid = geteuid();
 561
 562         /*
 563          * Use uid-swapping to give up root privileges for the duration of
 564          * option processing.  We will re-instantiate the rights when we are
 565          * ready to create the privileged port, and will permanently drop
 566          * them when the port has been created (actually, when the connection
 567          * has been made, as we may need to create the port several times).
 568          */
 569         PRIV_END;
 570
 571 #ifdef HAVE_SETRLIMIT
 572         /* If we are installed setuid root be careful to not drop core. */
 573         if (original_real_uid != original_effective_uid) {
 574                 struct rlimit rlim;
 575                 rlim.rlim_cur = rlim.rlim_max = 0;
 576                 if (setrlimit(RLIMIT_CORE, &rlim) < 0)
 577                         fatal("setrlimit failed: %.100s", strerror(errno));
 578         }
 579 #endif
 580         /* Get user data. */
 581         pw = getpwuid(original_real_uid);
 582         if (!pw) {
 583                 logit("No user exists for uid %lu", (u_long)original_real_uid);
 584                 exit(255);
 585         }
 586         /* Take a copy of the returned structure. */
 587         pw = pwcopy(pw);
 588
 589         /*
 590          * Set our umask to something reasonable, as some files are created
 591          * with the default umask.  This will make them world-readable but
 592          * writable only by the owner, which is ok for all files for which we
 593          * don't set the modes explicitly.
 594          */
 595         umask(022);
 596
 597         setlocale(LC_CTYPE, "");
 598
 599         /*
 600          * Initialize option structure to indicate that no values have been
 601          * set.
 602          */
 603         initialize_options(&options);
 604
 605         /* Parse command-line arguments. */
 606         host = NULL;
 607         use_syslog = 0;
 608         logfile = NULL;
 609         argv0 = av[0];
 610
 611  again:
 612         while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx"
 613             "ACD:E:F:GI:J:KL:MNO:PQ:R:S:TVw:W:XYy")) != -1) {
 614                 switch (opt) {
 615                 case '1':
 616                         options.protocol = SSH_PROTO_1;
 617                         break;
 618                 case '2':
 619                         options.protocol = SSH_PROTO_2;
 620                         break;
 621                 case '4':
 622                         options.address_family = AF_INET;
 623                         break;
 624                 case '6':
 625                         options.address_family = AF_INET6;
 626                         break;
 627                 case 'n':
 628                         stdin_null_flag = 1;
 629                         break;
 630                 case 'f':
 631                         fork_after_authentication_flag = 1;
 632                         stdin_null_flag = 1;
 633                         break;
 634                 case 'x':
 635                         options.forward_x11 = 0;
 636                         break;
 637                 case 'X':
 638                         options.forward_x11 = 1;
 639                         break;
 640                 case 'y':
 641                         use_syslog = 1;
 642                         break;
 643                 case 'E':
 644                         logfile = optarg;
 645                         break;
 646                 case 'G':
 647                         config_test = 1;
 648                         break;
 649                 case 'Y':
 650                         options.forward_x11 = 1;
 651                         options.forward_x11_trusted = 1;
 652                         break;
 653                 case 'g':
 654                         options.fwd_opts.gateway_ports = 1;
 655                         break;
 656                 case 'O':
 657                         if (options.stdio_forward_host != NULL)
 658                                 fatal("Cannot specify multiplexing "
 659                                     "command with -W");
 660                         else if (muxclient_command != 0)
 661                                 fatal("Multiplexing command already specified");
 662                         if (strcmp(optarg, "check") == 0)
 663                                 muxclient_command = SSHMUX_COMMAND_ALIVE_CHECK;
 664                         else if (strcmp(optarg, "forward") == 0)
 665                                 muxclient_command = SSHMUX_COMMAND_FORWARD;
 666                         else if (strcmp(optarg, "exit") == 0)
 667                                 muxclient_command = SSHMUX_COMMAND_TERMINATE;
 668                         else if (strcmp(optarg, "stop") == 0)
 669                                 muxclient_command = SSHMUX_COMMAND_STOP;
 670                         else if (strcmp(optarg, "cancel") == 0)
 671                                 muxclient_command = SSHMUX_COMMAND_CANCEL_FWD;
 672                         else
 673                                 fatal("Invalid multiplex command.");
 674                         break;
 675                 case 'P':       /* deprecated */
 676                         options.use_privileged_port = 0;
 677                         break;
 678                 case 'Q':
 679                         cp = NULL;
 680                         if (strcmp(optarg, "cipher") == 0)
 681                                 cp = cipher_alg_list('\n', 0);
 682                         else if (strcmp(optarg, "cipher-auth") == 0)
 683                                 cp = cipher_alg_list('\n', 1);
 684                         else if (strcmp(optarg, "mac") == 0)
 685                                 cp = mac_alg_list('\n');
 686                         else if (strcmp(optarg, "kex") == 0)
 687                                 cp = kex_alg_list('\n');
 688                         else if (strcmp(optarg, "key") == 0)
 689                                 cp = key_alg_list(0, 0);
 690                         else if (strcmp(optarg, "key-cert") == 0)
 691                                 cp = key_alg_list(1, 0);
 692                         else if (strcmp(optarg, "key-plain") == 0)
 693                                 cp = key_alg_list(0, 1);
 694                         else if (strcmp(optarg, "protocol-version") == 0) {
 695 #ifdef WITH_SSH1
 696                                 cp = xstrdup("1\n2");
 697 #else
 698                                 cp = xstrdup("2");
 699 #endif
 700                         }
 701                         if (cp == NULL)
 702                                 fatal("Unsupported query \"%s\"", optarg);
 703                         printf("%s\n", cp);
 704                         free(cp);
 705                         exit(0);
 706                         break;
 707                 case 'a':
 708                         options.forward_agent = 0;
 709                         break;
 710                 case 'A':
 711                         options.forward_agent = 1;
 712                         break;
 713                 case 'k':
 714                         options.gss_deleg_creds = 0;
 715                         break;
 716                 case 'K':
 717                         options.gss_authentication = 1;
 718                         options.gss_deleg_creds = 1;
 719                         break;
 720                 case 'i':
 721                         p = tilde_expand_filename(optarg, original_real_uid);
 722                         if (stat(p, &st) < 0)
 723                                 fprintf(stderr, "Warning: Identity file %s "
 724                                     "not accessible: %s.\n", p,
 725                                     strerror(errno));
 726                         else
 727                                 add_identity_file(&options, NULL, p, 1);
 728                         free(p);
 729                         break;
 730                 case 'I':
 731 #ifdef ENABLE_PKCS11
 732                         free(options.pkcs11_provider);
 733                         options.pkcs11_provider = xstrdup(optarg);
 734 #else
 735                         fprintf(stderr, "no support for PKCS#11.\n");
 736 #endif
 737                         break;
 738                 case 'J':
 739                         if (options.jump_host != NULL)
 740                                 fatal("Only a single -J option permitted");
 741                         if (options.proxy_command != NULL)
 742                                 fatal("Cannot specify -J with ProxyCommand");
 743                         if (parse_jump(optarg, &options, 1) == -1)
 744                                 fatal("Invalid -J argument");
 745                         options.proxy_command = xstrdup("none");
 746                         break;
 747                 case 't':
 748                         if (options.request_tty == REQUEST_TTY_YES)
 749                                 options.request_tty = REQUEST_TTY_FORCE;
 750                         else
 751                                 options.request_tty = REQUEST_TTY_YES;
 752                         break;
 753                 case 'v':
 754                         if (debug_flag == 0) {
 755                                 debug_flag = 1;
 756                                 options.log_level = SYSLOG_LEVEL_DEBUG1;
 757                         } else {
 758                                 if (options.log_level < SYSLOG_LEVEL_DEBUG3) {
 759                                         debug_flag++;
 760                                         options.log_level++;
 761                                 }
 762                         }
 763                         break;
 764                 case 'V':
 765                         if (options.version_addendum &&
 766                             *options.version_addendum != '\0')
 767                                 fprintf(stderr, "%s %s, %s\n", SSH_RELEASE,
 768                                     options.version_addendum,
 769                                     OPENSSL_VERSION);
 770                         else
 771                                 fprintf(stderr, "%s, %s\n", SSH_RELEASE,
 772                                     OPENSSL_VERSION);
 773                         if (opt == 'V')
 774                                 exit(0);
 775                         break;
 776                 case 'w':
 777                         if (options.tun_open == -1)
 778                                 options.tun_open = SSH_TUNMODE_DEFAULT;
 779                         options.tun_local = a2tun(optarg, &options.tun_remote);
 780                         if (options.tun_local == SSH_TUNID_ERR) {
 781                                 fprintf(stderr,
 782                                     "Bad tun device '%s'\n", optarg);
 783                                 exit(255);
 784                         }
 785                         break;
 786                 case 'W':
 787                         if (options.stdio_forward_host != NULL)
 788                                 fatal("stdio forward already specified");
 789                         if (muxclient_command != 0)
 790                                 fatal("Cannot specify stdio forward with -O");
 791                         if (parse_forward(&fwd, optarg, 1, 0)) {
 792                                 options.stdio_forward_host = fwd.listen_host;
 793                                 options.stdio_forward_port = fwd.listen_port;
 794                                 free(fwd.connect_host);
 795                         } else {
 796                                 fprintf(stderr,
 797                                     "Bad stdio forwarding specification '%s'\n",
 798                                     optarg);
 799                                 exit(255);
 800                         }
 801                         options.request_tty = REQUEST_TTY_NO;
 802                         no_shell_flag = 1;
 803                         break;
 804                 case 'q':
 805                         options.log_level = SYSLOG_LEVEL_QUIET;
 806                         break;
 807                 case 'e':
 808                         if (optarg[0] == '^' && optarg[2] == 0 &&
 809                             (u_char) optarg[1] >= 64 &&
 810                             (u_char) optarg[1] < 128)
 811                                 options.escape_char = (u_char) optarg[1] & 31;
 812                         else if (strlen(optarg) == 1)
 813                                 options.escape_char = (u_char) optarg[0];
 814                         else if (strcmp(optarg, "none") == 0)
 815                                 options.escape_char = SSH_ESCAPECHAR_NONE;
 816                         else {
 817                                 fprintf(stderr, "Bad escape character '%s'.\n",
 818                                     optarg);
 819                                 exit(255);
 820                         }
 821                         break;
 822                 case 'c':
 823                         if (ciphers_valid(*optarg == '+' ?
 824                             optarg + 1 : optarg)) {
 825                                 /* SSH2 only */
 826                                 free(options.ciphers);
 827                                 options.ciphers = xstrdup(optarg);
 828                                 options.cipher = SSH_CIPHER_INVALID;
 829                                 break;
 830                         }
 831                         /* SSH1 only */
 832                         options.cipher = cipher_number(optarg);
 833                         if (options.cipher == -1) {
 834                                 fprintf(stderr, "Unknown cipher type '%s'\n",
 835                                     optarg);
 836                                 exit(255);
 837                         }
 838                         if (options.cipher == SSH_CIPHER_3DES)
 839                                 options.ciphers = xstrdup("3des-cbc");
 840                         else if (options.cipher == SSH_CIPHER_BLOWFISH)
 841                                 options.ciphers = xstrdup("blowfish-cbc");
 842                         else
 843                                 options.ciphers = xstrdup(KEX_CLIENT_ENCRYPT);
 844                         break;
 845                 case 'm':
 846                         if (mac_valid(optarg)) {
 847                                 free(options.macs);
 848                                 options.macs = xstrdup(optarg);
 849                         } else {
 850                                 fprintf(stderr, "Unknown mac type '%s'\n",
 851                                     optarg);
 852                                 exit(255);
 853                         }
 854                         break;
 855                 case 'M':
 856                         if (options.control_master == SSHCTL_MASTER_YES)
 857                                 options.control_master = SSHCTL_MASTER_ASK;
 858                         else
 859                                 options.control_master = SSHCTL_MASTER_YES;
 860                         break;
 861                 case 'p':
 862                         options.port = a2port(optarg);
 863                         if (options.port <= 0) {
 864                                 fprintf(stderr, "Bad port '%s'\n", optarg);
 865                                 exit(255);
 866                         }
 867                         break;
 868                 case 'l':
 869                         options.user = optarg;
 870                         break;
 871
 872                 case 'L':
 873                         if (parse_forward(&fwd, optarg, 0, 0))
 874                                 add_local_forward(&options, &fwd);
 875                         else {
 876                                 fprintf(stderr,
 877                                     "Bad local forwarding specification '%s'\n",
 878                                     optarg);
 879                                 exit(255);
 880                         }
 881                         break;
 882
 883                 case 'R':
 884                         if (parse_forward(&fwd, optarg, 0, 1)) {
 885                                 add_remote_forward(&options, &fwd);
 886                         } else {
 887                                 fprintf(stderr,
 888                                     "Bad remote forwarding specification "
 889                                     "'%s'\n", optarg);
 890                                 exit(255);
 891                         }
 892                         break;
 893
 894                 case 'D':
 895                         if (parse_forward(&fwd, optarg, 1, 0)) {
 896                                 add_local_forward(&options, &fwd);
 897                         } else {
 898                                 fprintf(stderr,
 899                                     "Bad dynamic forwarding specification "
 900                                     "'%s'\n", optarg);
 901                                 exit(255);
 902                         }
 903                         break;
 904
 905                 case 'C':
 906                         options.compression = 1;
 907                         break;
 908                 case 'N':
 909                         no_shell_flag = 1;
 910                         options.request_tty = REQUEST_TTY_NO;
 911                         break;
 912                 case 'T':
 913                         options.request_tty = REQUEST_TTY_NO;
 914                         break;
 915                 case 'o':
 916                         line = xstrdup(optarg);
 917                         if (process_config_line(&options, pw,
 918                             host ? host : "", host ? host : "", line,
 919                             "command-line", 0, NULL, SSHCONF_USERCONF) != 0)
 920                                 exit(255);
 921                         free(line);
 922                         break;
 923                 case 's':
 924                         subsystem_flag = 1;
 925                         break;
 926                 case 'S':
 927                         free(options.control_path);
 928                         options.control_path = xstrdup(optarg);
 929                         break;
 930                 case 'b':
 931                         options.bind_address = optarg;
 932                         break;
 933                 case 'F':
 934                         config = optarg;
 935                         break;
 936                 default:
 937                         usage();
 938                 }
 939         }
 940
 941         ac -= optind;
 942         av += optind;
 943
 944         if (ac > 0 && !host) {
 945                 if (strrchr(*av, '@')) {
 946                         p = xstrdup(*av);
 947                         cp = strrchr(p, '@');
 948                         if (cp == NULL || cp == p)
 949                                 usage();
 950                         options.user = p;
 951                         *cp = '\0';
 952                         host = xstrdup(++cp);
 953                 } else
 954                         host = xstrdup(*av);
 955                 if (ac > 1) {
 956                         optind = optreset = 1;
 957                         goto again;
 958                 }
 959                 ac--, av++;
 960         }
 961
 962         /* Check that we got a host name. */
 963         if (!host)
 964                 usage();
 965
 966         host_arg = xstrdup(host);
 967
 968 #ifdef WITH_OPENSSL
 969         OpenSSL_add_all_algorithms();
 970         ERR_load_crypto_strings();
 971 #endif
 972
 973         /* Initialize the command to execute on remote host. */
 974         buffer_init(&command);
 975
 976         /*
 977          * Save the command to execute on the remote host in a buffer. There
 978          * is no limit on the length of the command, except by the maximum
 979          * packet size.  Also sets the tty flag if there is no command.
 980          */
 981         if (!ac) {
 982                 /* No command specified - execute shell on a tty. */
 983                 if (subsystem_flag) {
 984                         fprintf(stderr,
 985                             "You must specify a subsystem to invoke.\n");
 986                         usage();
 987                 }
 988         } else {
 989                 /* A command has been specified.  Store it into the buffer. */
 990                 for (i = 0; i < ac; i++) {
 991                         if (i)
 992                                 buffer_append(&command, " ", 1);
 993                         buffer_append(&command, av[i], strlen(av[i]));
 994                 }
 995         }
 996
 997         /* Cannot fork to background if no command. */
 998         if (fork_after_authentication_flag && buffer_len(&command) == 0 &&
 999             !no_shell_flag)
1000                 fatal("Cannot fork into background without a command "
1001                     "to execute.");
1002
1003         /*
1004          * Initialize "log" output.  Since we are the client all output
1005          * goes to stderr unless otherwise specified by -y or -E.
1006          */
1007         if (use_syslog && logfile != NULL)
1008                 fatal("Can't specify both -y and -E");
1009         if (logfile != NULL)
1010                 log_redirect_stderr_to(logfile);
1011         log_init(argv0,
1012             options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level,
1013             SYSLOG_FACILITY_USER, !use_syslog);
1014
1015         if (debug_flag)
1016                 /* version_addendum is always NULL at this point */
1017                 logit("%s, %s", SSH_RELEASE, OPENSSL_VERSION);
1018
1019         /* Parse the configuration files */
1020         process_config_files(host_arg, pw, 0);
1021
1022         /* Hostname canonicalisation needs a few options filled. */
1023         fill_default_options_for_canonicalization(&options);
1024
1025         /* If the user has replaced the hostname then take it into use now */
1026         if (options.hostname != NULL) {
1027                 /* NB. Please keep in sync with readconf.c:match_cfg_line() */
1028                 cp = percent_expand(options.hostname,
1029                     "h", host, (char *)NULL);
1030                 free(host);
1031                 host = cp;
1032                 free(options.hostname);
1033                 options.hostname = xstrdup(host);
1034         }
1035
1036         /* If canonicalization requested then try to apply it */
1037         lowercase(host);
1038         if (options.canonicalize_hostname != SSH_CANONICALISE_NO)
1039                 addrs = resolve_canonicalize(&host, options.port);
1040
1041         /*
1042          * If CanonicalizePermittedCNAMEs have been specified but
1043          * other canonicalization did not happen (by not being requested
1044          * or by failing with fallback) then the hostname may still be changed
1045          * as a result of CNAME following.
1046          *
1047          * Try to resolve the bare hostname name using the system resolver's
1048          * usual search rules and then apply the CNAME follow rules.
1049          *
1050          * Skip the lookup if a ProxyCommand is being used unless the user
1051          * has specifically requested canonicalisation for this case via
1052          * CanonicalizeHostname=always
1053          */
1054         direct = option_clear_or_none(options.proxy_command) &&
1055             options.jump_host == NULL;
1056         if (addrs == NULL && options.num_permitted_cnames != 0 && (direct ||
1057             options.canonicalize_hostname == SSH_CANONICALISE_ALWAYS)) {
1058                 if ((addrs = resolve_host(host, options.port,
1059                     option_clear_or_none(options.proxy_command),
1060                     cname, sizeof(cname))) == NULL) {
1061                         /* Don't fatal proxied host names not in the DNS */
1062                         if (option_clear_or_none(options.proxy_command))
1063                                 cleanup_exit(255); /* logged in resolve_host */
1064                 } else
1065                         check_follow_cname(direct, &host, cname);
1066         }
1067
1068         /*
1069          * If canonicalisation is enabled then re-parse the configuration
1070          * files as new stanzas may match.
1071          */
1072         if (options.canonicalize_hostname != 0) {
1073                 debug("Re-reading configuration after hostname "
1074                     "canonicalisation");
1075                 free(options.hostname);
1076                 options.hostname = xstrdup(host);
1077                 process_config_files(host_arg, pw, 1);
1078                 /*
1079                  * Address resolution happens early with canonicalisation
1080                  * enabled and the port number may have changed since, so
1081                  * reset it in address list
1082                  */
1083                 if (addrs != NULL && options.port > 0)
1084                         set_addrinfo_port(addrs, options.port);
1085         }
1086
1087         /* Fill configuration defaults. */
1088         fill_default_options(&options);
1089
1090         /*
1091          * If ProxyJump option specified, then construct a ProxyCommand now.
1092          */
1093         if (options.jump_host != NULL) {
1094                 char port_s[8];
1095
1096                 /* Consistency check */
1097                 if (options.proxy_command != NULL)
1098                         fatal("inconsistent options: ProxyCommand+ProxyJump");
1099                 /* Never use FD passing for ProxyJump */
1100                 options.proxy_use_fdpass = 0;
1101                 snprintf(port_s, sizeof(port_s), "%d", options.jump_port);
1102                 xasprintf(&options.proxy_command,
1103                     "ssh%s%s%s%s%s%s%s%s%s%.*s -W %%h:%%p %s",
1104                     /* Optional "-l user" argument if jump_user set */
1105                     options.jump_user == NULL ? "" : " -l ",
1106                     options.jump_user == NULL ? "" : options.jump_user,
1107                     /* Optional "-p port" argument if jump_port set */
1108                     options.jump_port <= 0 ? "" : " -p ",
1109                     options.jump_port <= 0 ? "" : port_s,
1110                     /* Optional additional jump hosts ",..." */
1111                     options.jump_extra == NULL ? "" : " -J ",
1112                     options.jump_extra == NULL ? "" : options.jump_extra,
1113                     /* Optional "-F" argumment if -F specified */
1114                     config == NULL ? "" : " -F ",
1115                     config == NULL ? "" : config,
1116                     /* Optional "-v" arguments if -v set */
1117                     debug_flag ? " -" : "",
1118                     debug_flag, "vvv",
1119                     /* Mandatory hostname */
1120                     options.jump_host);
1121                 debug("Setting implicit ProxyCommand from ProxyJump: %s",
1122                     options.proxy_command);
1123         }
1124
1125         if (options.port == 0)
1126                 options.port = default_ssh_port();
1127         channel_set_af(options.address_family);
1128
1129         /* Tidy and check options */
1130         if (options.host_key_alias != NULL)
1131                 lowercase(options.host_key_alias);
1132         if (options.proxy_command != NULL &&
1133             strcmp(options.proxy_command, "-") == 0 &&
1134             options.proxy_use_fdpass)
1135                 fatal("ProxyCommand=- and ProxyUseFDPass are incompatible");
1136         if (options.control_persist &&
1137             options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK) {
1138                 debug("UpdateHostKeys=ask is incompatible with ControlPersist; "
1139                     "disabling");
1140                 options.update_hostkeys = 0;
1141         }
1142         if (options.connection_attempts <= 0)
1143                 fatal("Invalid number of ConnectionAttempts");
1144 #ifndef HAVE_CYGWIN
1145         if (original_effective_uid != 0)
1146                 options.use_privileged_port = 0;
1147 #endif
1148
1149         /* reinit */
1150         log_init(argv0, options.log_level, SYSLOG_FACILITY_USER, !use_syslog);
1151
1152         if (options.request_tty == REQUEST_TTY_YES ||
1153             options.request_tty == REQUEST_TTY_FORCE)
1154                 tty_flag = 1;
1155
1156         /* Allocate a tty by default if no command specified. */
1157         if (buffer_len(&command) == 0)
1158                 tty_flag = options.request_tty != REQUEST_TTY_NO;
1159
1160         /* Force no tty */
1161         if (options.request_tty == REQUEST_TTY_NO || muxclient_command != 0)
1162                 tty_flag = 0;
1163         /* Do not allocate a tty if stdin is not a tty. */
1164         if ((!isatty(fileno(stdin)) || stdin_null_flag) &&
1165             options.request_tty != REQUEST_TTY_FORCE) {
1166                 if (tty_flag)
1167                         logit("Pseudo-terminal will not be allocated because "
1168                             "stdin is not a terminal.");
1169                 tty_flag = 0;
1170         }
1171
1172         seed_rng();
1173
1174         if (options.user == NULL)
1175                 options.user = xstrdup(pw->pw_name);
1176
1177         if (gethostname(thishost, sizeof(thishost)) == -1)
1178                 fatal("gethostname: %s", strerror(errno));
1179         strlcpy(shorthost, thishost, sizeof(shorthost));
1180         shorthost[strcspn(thishost, ".")] = '\0';
1181         snprintf(portstr, sizeof(portstr), "%d", options.port);
1182         snprintf(uidstr, sizeof(uidstr), "%d", pw->pw_uid);
1183
1184         /* Find canonic host name. */
1185         if (strchr(host, '.') == 0) {
1186                 struct addrinfo hints;
1187                 struct addrinfo *ai = NULL;
1188                 int errgai;
1189                 memset(&hints, 0, sizeof(hints));
1190                 hints.ai_family = options.address_family;
1191                 hints.ai_flags = AI_CANONNAME;
1192                 hints.ai_socktype = SOCK_STREAM;
1193                 errgai = getaddrinfo(host, NULL, &hints, &ai);
1194                 if (errgai == 0) {
1195                         if (ai->ai_canonname != NULL)
1196                                 host = xstrdup(ai->ai_canonname);
1197                         freeaddrinfo(ai);
1198                 }
1199         }
1200
1201         if ((md = ssh_digest_start(SSH_DIGEST_SHA1)) == NULL ||
1202             ssh_digest_update(md, thishost, strlen(thishost)) < 0 ||
1203             ssh_digest_update(md, host, strlen(host)) < 0 ||
1204             ssh_digest_update(md, portstr, strlen(portstr)) < 0 ||
1205             ssh_digest_update(md, options.user, strlen(options.user)) < 0 ||
1206             ssh_digest_final(md, conn_hash, sizeof(conn_hash)) < 0)
1207                 fatal("%s: mux digest failed", __func__);
1208         ssh_digest_free(md);
1209         conn_hash_hex = tohex(conn_hash, ssh_digest_bytes(SSH_DIGEST_SHA1));
1210
1211         if (options.local_command != NULL) {
1212                 debug3("expanding LocalCommand: %s", options.local_command);
1213                 cp = options.local_command;
1214                 options.local_command = percent_expand(cp,
1215                     "C", conn_hash_hex,
1216                     "L", shorthost,
1217                     "d", pw->pw_dir,
1218                     "h", host,
1219                     "l", thishost,
1220                     "n", host_arg,
1221                     "p", portstr,
1222                     "r", options.user,
1223                     "u", pw->pw_name,
1224                     (char *)NULL);
1225                 debug3("expanded LocalCommand: %s", options.local_command);
1226                 free(cp);
1227         }
1228
1229         if (options.control_path != NULL) {
1230                 cp = tilde_expand_filename(options.control_path,
1231                     original_real_uid);
1232                 free(options.control_path);
1233                 options.control_path = percent_expand(cp,
1234                     "C", conn_hash_hex,
1235                     "L", shorthost,
1236                     "h", host,
1237                     "l", thishost,
1238                     "n", host_arg,
1239                     "p", portstr,
1240                     "r", options.user,
1241                     "u", pw->pw_name,
1242                     "i", uidstr,
1243                     (char *)NULL);
1244                 free(cp);
1245         }
1246         free(conn_hash_hex);
1247
1248         if (config_test) {
1249                 dump_client_config(&options, host);
1250                 exit(0);
1251         }
1252
1253         if (muxclient_command != 0 && options.control_path == NULL)
1254                 fatal("No ControlPath specified for \"-O\" command");
1255         if (options.control_path != NULL)
1256                 muxclient(options.control_path);
1257
1258         /*
1259          * If hostname canonicalisation was not enabled, then we may not
1260          * have yet resolved the hostname. Do so now.
1261          */
1262         if (addrs == NULL && options.proxy_command == NULL) {
1263                 debug2("resolving \"%s\" port %d", host, options.port);
1264                 if ((addrs = resolve_host(host, options.port, 1,
1265                     cname, sizeof(cname))) == NULL)
1266                         cleanup_exit(255); /* resolve_host logs the error */
1267         }
1268
1269         timeout_ms = options.connection_timeout * 1000;
1270
1271         /* Open a connection to the remote host. */
1272         if (ssh_connect(host, addrs, &hostaddr, options.port,
1273             options.address_family, options.connection_attempts,
1274             &timeout_ms, options.tcp_keep_alive,
1275             options.use_privileged_port) != 0)
1276                 exit(255);
1277
1278         if (addrs != NULL)
1279                 freeaddrinfo(addrs);
1280
1281         packet_set_timeout(options.server_alive_interval,
1282             options.server_alive_count_max);
1283
1284         ssh = active_state; /* XXX */
1285
1286         if (timeout_ms > 0)
1287                 debug3("timeout: %d ms remain after connect", timeout_ms);
1288
1289         /*
1290          * If we successfully made the connection, load the host private key
1291          * in case we will need it later for combined rsa-rhosts
1292          * authentication. This must be done before releasing extra
1293          * privileges, because the file is only readable by root.
1294          * If we cannot access the private keys, load the public keys
1295          * instead and try to execute the ssh-keysign helper instead.
1296          */
1297         sensitive_data.nkeys = 0;
1298         sensitive_data.keys = NULL;
1299         sensitive_data.external_keysign = 0;
1300         if (options.rhosts_rsa_authentication ||
1301             options.hostbased_authentication) {
1302                 sensitive_data.nkeys = 9;
1303                 sensitive_data.keys = xcalloc(sensitive_data.nkeys,
1304                     sizeof(Key));
1305                 for (i = 0; i < sensitive_data.nkeys; i++)
1306                         sensitive_data.keys[i] = NULL;
1307
1308                 PRIV_START;
1309 #if WITH_SSH1
1310                 sensitive_data.keys[0] = key_load_private_type(KEY_RSA1,
1311                     _PATH_HOST_KEY_FILE, "", NULL, NULL);
1312 #endif
1313 #ifdef OPENSSL_HAS_ECC
1314                 sensitive_data.keys[1] = key_load_private_cert(KEY_ECDSA,
1315                     _PATH_HOST_ECDSA_KEY_FILE, "", NULL);
1316 #endif
1317                 sensitive_data.keys[2] = key_load_private_cert(KEY_ED25519,
1318                     _PATH_HOST_ED25519_KEY_FILE, "", NULL);
1319                 sensitive_data.keys[3] = key_load_private_cert(KEY_RSA,
1320                     _PATH_HOST_RSA_KEY_FILE, "", NULL);
1321                 sensitive_data.keys[4] = key_load_private_cert(KEY_DSA,
1322                     _PATH_HOST_DSA_KEY_FILE, "", NULL);
1323 #ifdef OPENSSL_HAS_ECC
1324                 sensitive_data.keys[5] = key_load_private_type(KEY_ECDSA,
1325                     _PATH_HOST_ECDSA_KEY_FILE, "", NULL, NULL);
1326 #endif
1327                 sensitive_data.keys[6] = key_load_private_type(KEY_ED25519,
1328                     _PATH_HOST_ED25519_KEY_FILE, "", NULL, NULL);
1329                 sensitive_data.keys[7] = key_load_private_type(KEY_RSA,
1330                     _PATH_HOST_RSA_KEY_FILE, "", NULL, NULL);
1331                 sensitive_data.keys[8] = key_load_private_type(KEY_DSA,
1332                     _PATH_HOST_DSA_KEY_FILE, "", NULL, NULL);
1333                 PRIV_END;
1334
1335                 if (options.hostbased_authentication == 1 &&
1336                     sensitive_data.keys[0] == NULL &&
1337                     sensitive_data.keys[5] == NULL &&
1338                     sensitive_data.keys[6] == NULL &&
1339                     sensitive_data.keys[7] == NULL &&
1340                     sensitive_data.keys[8] == NULL) {
1341 #ifdef OPENSSL_HAS_ECC
1342                         sensitive_data.keys[1] = key_load_cert(
1343                             _PATH_HOST_ECDSA_KEY_FILE);
1344 #endif
1345                         sensitive_data.keys[2] = key_load_cert(
1346                             _PATH_HOST_ED25519_KEY_FILE);
1347                         sensitive_data.keys[3] = key_load_cert(
1348                             _PATH_HOST_RSA_KEY_FILE);
1349                         sensitive_data.keys[4] = key_load_cert(
1350                             _PATH_HOST_DSA_KEY_FILE);
1351 #ifdef OPENSSL_HAS_ECC
1352                         sensitive_data.keys[5] = key_load_public(
1353                             _PATH_HOST_ECDSA_KEY_FILE, NULL);
1354 #endif
1355                         sensitive_data.keys[6] = key_load_public(
1356                             _PATH_HOST_ED25519_KEY_FILE, NULL);
1357                         sensitive_data.keys[7] = key_load_public(
1358                             _PATH_HOST_RSA_KEY_FILE, NULL);
1359                         sensitive_data.keys[8] = key_load_public(
1360                             _PATH_HOST_DSA_KEY_FILE, NULL);
1361                         sensitive_data.external_keysign = 1;
1362                 }
1363         }
1364         /*
1365          * Get rid of any extra privileges that we may have.  We will no
1366          * longer need them.  Also, extra privileges could make it very hard
1367          * to read identity files and other non-world-readable files from the
1368          * user's home directory if it happens to be on a NFS volume where
1369          * root is mapped to nobody.
1370          */
1371         if (original_effective_uid == 0) {
1372                 PRIV_START;
1373                 permanently_set_uid(pw);
1374         }
1375
1376         /*
1377          * Now that we are back to our own permissions, create ~/.ssh
1378          * directory if it doesn't already exist.
1379          */
1380         if (config == NULL) {
1381                 r = snprintf(buf, sizeof buf, "%s%s%s", pw->pw_dir,
1382                     strcmp(pw->pw_dir, "/") ? "/" : "", _PATH_SSH_USER_DIR);
1383                 if (r > 0 && (size_t)r < sizeof(buf) && stat(buf, &st) < 0) {
1384 #ifdef WITH_SELINUX
1385                         ssh_selinux_setfscreatecon(buf);
1386 #endif
1387                         if (mkdir(buf, 0700) < 0)
1388                                 error("Could not create directory '%.200s'.",
1389                                     buf);
1390 #ifdef WITH_SELINUX
1391                         ssh_selinux_setfscreatecon(NULL);
1392 #endif
1393                 }
1394         }
1395         /* load options.identity_files */
1396         load_public_identity_files();
1397
1398         /* optionally set the SSH_AUTHSOCKET_ENV_NAME varibale */
1399         if (options.identity_agent &&
1400             strcmp(options.identity_agent, SSH_AUTHSOCKET_ENV_NAME) != 0) {
1401                 if (strcmp(options.identity_agent, "none") == 0) {
1402                         unsetenv(SSH_AUTHSOCKET_ENV_NAME);
1403                 } else {
1404                         p = tilde_expand_filename(options.identity_agent,
1405                             original_real_uid);
1406                         cp = percent_expand(p, "d", pw->pw_dir,
1407                             "u", pw->pw_name, "l", thishost, "h", host,
1408                             "r", options.user, (char *)NULL);
1409                         setenv(SSH_AUTHSOCKET_ENV_NAME, cp, 1);
1410                         free(cp);
1411                         free(p);
1412                 }
1413         }
1414
1415         /* Expand ~ in known host file names. */
1416         tilde_expand_paths(options.system_hostfiles,
1417             options.num_system_hostfiles);
1418         tilde_expand_paths(options.user_hostfiles, options.num_user_hostfiles);
1419
1420         signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */
1421         signal(SIGCHLD, main_sigchld_handler);
1422
1423         /* Log into the remote system.  Never returns if the login fails. */
1424         ssh_login(&sensitive_data, host, (struct sockaddr *)&hostaddr,
1425             options.port, pw, timeout_ms);
1426
1427         if (packet_connection_is_on_socket()) {
1428                 verbose("Authenticated to %s ([%s]:%d).", host,
1429                     ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
1430         } else {
1431                 verbose("Authenticated to %s (via proxy).", host);
1432         }
1433
1434         /* We no longer need the private host keys.  Clear them now. */
1435         if (sensitive_data.nkeys != 0) {
1436                 for (i = 0; i < sensitive_data.nkeys; i++) {
1437                         if (sensitive_data.keys[i] != NULL) {
1438                                 /* Destroys contents safely */
1439                                 debug3("clear hostkey %d", i);
1440                                 key_free(sensitive_data.keys[i]);
1441                                 sensitive_data.keys[i] = NULL;
1442                         }
1443                 }
1444                 free(sensitive_data.keys);
1445         }
1446         for (i = 0; i < options.num_identity_files; i++) {
1447                 free(options.identity_files[i]);
1448                 options.identity_files[i] = NULL;
1449                 if (options.identity_keys[i]) {
1450                         key_free(options.identity_keys[i]);
1451                         options.identity_keys[i] = NULL;
1452                 }
1453         }
1454         for (i = 0; i < options.num_certificate_files; i++) {
1455                 free(options.certificate_files[i]);
1456                 options.certificate_files[i] = NULL;
1457         }
1458
1459         exit_status = compat20 ? ssh_session2() : ssh_session();
1460         packet_close();
1461
1462         if (options.control_path != NULL && muxserver_sock != -1)
1463                 unlink(options.control_path);
1464
1465         /* Kill ProxyCommand if it is running. */
1466         ssh_kill_proxy_command();
1467
1468         return exit_status;
1469 }
1470
1471 static void
1472 control_persist_detach(void)
1473 {
1474         pid_t pid;
1475         int devnull, keep_stderr;
1476
1477         debug("%s: backgrounding master process", __func__);
1478
1479         /*
1480          * master (current process) into the background, and make the
1481          * foreground process a client of the backgrounded master.
1482          */
1483         switch ((pid = fork())) {
1484         case -1:
1485                 fatal("%s: fork: %s", __func__, strerror(errno));
1486         case 0:
1487                 /* Child: master process continues mainloop */
1488                 break;
1489         default:
1490                 /* Parent: set up mux slave to connect to backgrounded master */
1491                 debug2("%s: background process is %ld", __func__, (long)pid);
1492                 stdin_null_flag = ostdin_null_flag;
1493                 options.request_tty = orequest_tty;
1494                 tty_flag = otty_flag;
1495                 close(muxserver_sock);
1496                 muxserver_sock = -1;
1497                 options.control_master = SSHCTL_MASTER_NO;
1498                 muxclient(options.control_path);
1499                 /* muxclient() doesn't return on success. */
1500                 fatal("Failed to connect to new control master");
1501         }
1502         if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1) {
1503                 error("%s: open(\"/dev/null\"): %s", __func__,
1504                     strerror(errno));
1505         } else {
1506                 keep_stderr = log_is_on_stderr() && debug_flag;
1507                 if (dup2(devnull, STDIN_FILENO) == -1 ||
1508                     dup2(devnull, STDOUT_FILENO) == -1 ||
1509                     (!keep_stderr && dup2(devnull, STDERR_FILENO) == -1))
1510                         error("%s: dup2: %s", __func__, strerror(errno));
1511                 if (devnull > STDERR_FILENO)
1512                         close(devnull);
1513         }
1514         daemon(1, 1);
1515         setproctitle("%s [mux]", options.control_path);
1516 }
1517
1518 /* Do fork() after authentication. Used by "ssh -f" */
1519 static void
1520 fork_postauth(void)
1521 {
1522         if (need_controlpersist_detach)
1523                 control_persist_detach();
1524         debug("forking to background");
1525         fork_after_authentication_flag = 0;
1526         if (daemon(1, 1) < 0)
1527                 fatal("daemon() failed: %.200s", strerror(errno));
1528 }
1529
1530 /* Callback for remote forward global requests */
1531 static void
1532 ssh_confirm_remote_forward(int type, u_int32_t seq, void *ctxt)
1533 {
1534         struct Forward *rfwd = (struct Forward *)ctxt;
1535
1536         /* XXX verbose() on failure? */
1537         debug("remote forward %s for: listen %s%s%d, connect %s:%d",
1538             type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure",
1539             rfwd->listen_path ? rfwd->listen_path :
1540             rfwd->listen_host ? rfwd->listen_host : "",
1541             (rfwd->listen_path || rfwd->listen_host) ? ":" : "",
1542             rfwd->listen_port, rfwd->connect_path ? rfwd->connect_path :
1543             rfwd->connect_host, rfwd->connect_port);
1544         if (rfwd->listen_path == NULL && rfwd->listen_port == 0) {
1545                 if (type == SSH2_MSG_REQUEST_SUCCESS) {
1546                         rfwd->allocated_port = packet_get_int();
1547                         logit("Allocated port %u for remote forward to %s:%d",
1548                             rfwd->allocated_port,
1549                             rfwd->connect_host, rfwd->connect_port);
1550                         channel_update_permitted_opens(rfwd->handle,
1551                             rfwd->allocated_port);
1552                 } else {
1553                         channel_update_permitted_opens(rfwd->handle, -1);
1554                 }
1555         }
1556
1557         if (type == SSH2_MSG_REQUEST_FAILURE) {
1558                 if (options.exit_on_forward_failure) {
1559                         if (rfwd->listen_path != NULL)
1560                                 fatal("Error: remote port forwarding failed "
1561                                     "for listen path %s", rfwd->listen_path);
1562                         else
1563                                 fatal("Error: remote port forwarding failed "
1564                                     "for listen port %d", rfwd->listen_port);
1565                 } else {
1566                         if (rfwd->listen_path != NULL)
1567                                 logit("Warning: remote port forwarding failed "
1568                                     "for listen path %s", rfwd->listen_path);
1569                         else
1570                                 logit("Warning: remote port forwarding failed "
1571                                     "for listen port %d", rfwd->listen_port);
1572                 }
1573         }
1574         if (++remote_forward_confirms_received == options.num_remote_forwards) {
1575                 debug("All remote forwarding requests processed");
1576                 if (fork_after_authentication_flag)
1577                         fork_postauth();
1578         }
1579 }
1580
1581 static void
1582 client_cleanup_stdio_fwd(int id, void *arg)
1583 {
1584         debug("stdio forwarding: done");
1585         cleanup_exit(0);
1586 }
1587
1588 static void
1589 ssh_stdio_confirm(int id, int success, void *arg)
1590 {
1591         if (!success)
1592                 fatal("stdio forwarding failed");
1593 }
1594
1595 static void
1596 ssh_init_stdio_forwarding(void)
1597 {
1598         Channel *c;
1599         int in, out;
1600
1601         if (options.stdio_forward_host == NULL)
1602                 return;
1603         if (!compat20)
1604                 fatal("stdio forwarding require Protocol 2");
1605
1606         debug3("%s: %s:%d", __func__, options.stdio_forward_host,
1607             options.stdio_forward_port);
1608
1609         if ((in = dup(STDIN_FILENO)) < 0 ||
1610             (out = dup(STDOUT_FILENO)) < 0)
1611                 fatal("channel_connect_stdio_fwd: dup() in/out failed");
1612         if ((c = channel_connect_stdio_fwd(options.stdio_forward_host,
1613             options.stdio_forward_port, in, out)) == NULL)
1614                 fatal("%s: channel_connect_stdio_fwd failed", __func__);
1615         channel_register_cleanup(c->self, client_cleanup_stdio_fwd, 0);
1616         channel_register_open_confirm(c->self, ssh_stdio_confirm, NULL);
1617 }
1618
1619 static void
1620 ssh_init_forwarding(void)
1621 {
1622         int success = 0;
1623         int i;
1624
1625         /* Initiate local TCP/IP port forwardings. */
1626         for (i = 0; i < options.num_local_forwards; i++) {
1627                 debug("Local connections to %.200s:%d forwarded to remote "
1628                     "address %.200s:%d",
1629                     (options.local_forwards[i].listen_path != NULL) ?
1630                     options.local_forwards[i].listen_path :
1631                     (options.local_forwards[i].listen_host == NULL) ?
1632                     (options.fwd_opts.gateway_ports ? "*" : "LOCALHOST") :
1633                     options.local_forwards[i].listen_host,
1634                     options.local_forwards[i].listen_port,
1635                     (options.local_forwards[i].connect_path != NULL) ?
1636                     options.local_forwards[i].connect_path :
1637                     options.local_forwards[i].connect_host,
1638                     options.local_forwards[i].connect_port);
1639                 success += channel_setup_local_fwd_listener(
1640                     &options.local_forwards[i], &options.fwd_opts);
1641         }
1642         if (i > 0 && success != i && options.exit_on_forward_failure)
1643                 fatal("Could not request local forwarding.");
1644         if (i > 0 && success == 0)
1645                 error("Could not request local forwarding.");
1646
1647         /* Initiate remote TCP/IP port forwardings. */
1648         for (i = 0; i < options.num_remote_forwards; i++) {
1649                 debug("Remote connections from %.200s:%d forwarded to "
1650                     "local address %.200s:%d",
1651                     (options.remote_forwards[i].listen_path != NULL) ?
1652                     options.remote_forwards[i].listen_path :
1653                     (options.remote_forwards[i].listen_host == NULL) ?
1654                     "LOCALHOST" : options.remote_forwards[i].listen_host,
1655                     options.remote_forwards[i].listen_port,
1656                     (options.remote_forwards[i].connect_path != NULL) ?
1657                     options.remote_forwards[i].connect_path :
1658                     options.remote_forwards[i].connect_host,
1659                     options.remote_forwards[i].connect_port);
1660                 options.remote_forwards[i].handle =
1661                     channel_request_remote_forwarding(
1662                     &options.remote_forwards[i]);
1663                 if (options.remote_forwards[i].handle < 0) {
1664                         if (options.exit_on_forward_failure)
1665                                 fatal("Could not request remote forwarding.");
1666                         else
1667                                 logit("Warning: Could not request remote "
1668                                     "forwarding.");
1669                 } else {
1670                         client_register_global_confirm(ssh_confirm_remote_forward,
1671                             &options.remote_forwards[i]);
1672                 }
1673         }
1674
1675         /* Initiate tunnel forwarding. */
1676         if (options.tun_open != SSH_TUNMODE_NO) {
1677                 if (client_request_tun_fwd(options.tun_open,
1678                     options.tun_local, options.tun_remote) == -1) {
1679                         if (options.exit_on_forward_failure)
1680                                 fatal("Could not request tunnel forwarding.");
1681                         else
1682                                 error("Could not request tunnel forwarding.");
1683                 }
1684         }
1685 }
1686
1687 static void
1688 check_agent_present(void)
1689 {
1690         int r;
1691
1692         if (options.forward_agent) {
1693                 /* Clear agent forwarding if we don't have an agent. */
1694                 if ((r = ssh_get_authentication_socket(NULL)) != 0) {
1695                         options.forward_agent = 0;
1696                         if (r != SSH_ERR_AGENT_NOT_PRESENT)
1697                                 debug("ssh_get_authentication_socket: %s",
1698                                     ssh_err(r));
1699                 }
1700         }
1701 }
1702
1703 static int
1704 ssh_session(void)
1705 {
1706         int type;
1707         int interactive = 0;
1708         int have_tty = 0;
1709         struct winsize ws;
1710         char *cp;
1711         const char *display;
1712         char *proto = NULL, *data = NULL;
1713
1714         /* Enable compression if requested. */
1715         if (options.compression) {
1716                 debug("Requesting compression at level %d.",
1717                     options.compression_level);
1718
1719                 if (options.compression_level < 1 ||
1720                     options.compression_level > 9)
1721                         fatal("Compression level must be from 1 (fast) to "
1722                             "9 (slow, best).");
1723
1724                 /* Send the request. */
1725                 packet_start(SSH_CMSG_REQUEST_COMPRESSION);
1726                 packet_put_int(options.compression_level);
1727                 packet_send();
1728                 packet_write_wait();
1729                 type = packet_read();
1730                 if (type == SSH_SMSG_SUCCESS)
1731                         packet_start_compression(options.compression_level);
1732                 else if (type == SSH_SMSG_FAILURE)
1733                         logit("Warning: Remote host refused compression.");
1734                 else
1735                         packet_disconnect("Protocol error waiting for "
1736                             "compression response.");
1737         }
1738         /* Allocate a pseudo tty if appropriate. */
1739         if (tty_flag) {
1740                 debug("Requesting pty.");
1741
1742                 /* Start the packet. */
1743                 packet_start(SSH_CMSG_REQUEST_PTY);
1744
1745                 /* Store TERM in the packet.  There is no limit on the
1746                    length of the string. */
1747                 cp = getenv("TERM");
1748                 if (!cp)
1749                         cp = "";
1750                 packet_put_cstring(cp);
1751
1752                 /* Store window size in the packet. */
1753                 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
1754                         memset(&ws, 0, sizeof(ws));
1755                 packet_put_int((u_int)ws.ws_row);
1756                 packet_put_int((u_int)ws.ws_col);
1757                 packet_put_int((u_int)ws.ws_xpixel);
1758                 packet_put_int((u_int)ws.ws_ypixel);
1759
1760                 /* Store tty modes in the packet. */
1761                 tty_make_modes(fileno(stdin), NULL);
1762
1763                 /* Send the packet, and wait for it to leave. */
1764                 packet_send();
1765                 packet_write_wait();
1766
1767                 /* Read response from the server. */
1768                 type = packet_read();
1769                 if (type == SSH_SMSG_SUCCESS) {
1770                         interactive = 1;
1771                         have_tty = 1;
1772                 } else if (type == SSH_SMSG_FAILURE)
1773                         logit("Warning: Remote host failed or refused to "
1774                             "allocate a pseudo tty.");
1775                 else
1776                         packet_disconnect("Protocol error waiting for pty "
1777                             "request response.");
1778         }
1779         /* Request X11 forwarding if enabled and DISPLAY is set. */
1780         display = getenv("DISPLAY");
1781         if (display == NULL && options.forward_x11)
1782                 debug("X11 forwarding requested but DISPLAY not set");
1783         if (options.forward_x11 && client_x11_get_proto(display,
1784             options.xauth_location, options.forward_x11_trusted,
1785             options.forward_x11_timeout, &proto, &data) == 0) {
1786                 /* Request forwarding with authentication spoofing. */
1787                 debug("Requesting X11 forwarding with authentication "
1788                     "spoofing.");
1789                 x11_request_forwarding_with_spoofing(0, display, proto,
1790                     data, 0);
1791                 /* Read response from the server. */
1792                 type = packet_read();
1793                 if (type == SSH_SMSG_SUCCESS) {
1794                         interactive = 1;
1795                 } else if (type == SSH_SMSG_FAILURE) {
1796                         logit("Warning: Remote host denied X11 forwarding.");
1797                 } else {
1798                         packet_disconnect("Protocol error waiting for X11 "
1799                             "forwarding");
1800                 }
1801         }
1802         /* Tell the packet module whether this is an interactive session. */
1803         packet_set_interactive(interactive,
1804             options.ip_qos_interactive, options.ip_qos_bulk);
1805
1806         /* Request authentication agent forwarding if appropriate. */
1807         check_agent_present();
1808
1809         if (options.forward_agent) {
1810                 debug("Requesting authentication agent forwarding.");
1811                 auth_request_forwarding();
1812
1813                 /* Read response from the server. */
1814                 type = packet_read();
1815                 packet_check_eom();
1816                 if (type != SSH_SMSG_SUCCESS)
1817                         logit("Warning: Remote host denied authentication agent forwarding.");
1818         }
1819
1820         /* Initiate port forwardings. */
1821         ssh_init_stdio_forwarding();
1822         ssh_init_forwarding();
1823
1824         /* Execute a local command */
1825         if (options.local_command != NULL &&
1826             options.permit_local_command)
1827                 ssh_local_cmd(options.local_command);
1828
1829         /*
1830          * If requested and we are not interested in replies to remote
1831          * forwarding requests, then let ssh continue in the background.
1832          */
1833         if (fork_after_authentication_flag) {
1834                 if (options.exit_on_forward_failure &&
1835                     options.num_remote_forwards > 0) {
1836                         debug("deferring postauth fork until remote forward "
1837                             "confirmation received");
1838                 } else
1839                         fork_postauth();
1840         }
1841
1842         /*
1843          * If a command was specified on the command line, execute the
1844          * command now. Otherwise request the server to start a shell.
1845          */
1846         if (buffer_len(&command) > 0) {
1847                 int len = buffer_len(&command);
1848                 if (len > 900)
1849                         len = 900;
1850                 debug("Sending command: %.*s", len,
1851                     (u_char *)buffer_ptr(&command));
1852                 packet_start(SSH_CMSG_EXEC_CMD);
1853                 packet_put_string(buffer_ptr(&command), buffer_len(&command));
1854                 packet_send();
1855                 packet_write_wait();
1856         } else {
1857                 debug("Requesting shell.");
1858                 packet_start(SSH_CMSG_EXEC_SHELL);
1859                 packet_send();
1860                 packet_write_wait();
1861         }
1862
1863         /* Enter the interactive session. */
1864         return client_loop(have_tty, tty_flag ?
1865             options.escape_char : SSH_ESCAPECHAR_NONE, 0);
1866 }
1867
1868 /* request pty/x11/agent/tcpfwd/shell for channel */
1869 static void
1870 ssh_session2_setup(int id, int success, void *arg)
1871 {
1872         extern char **environ;
1873         const char *display;
1874         int interactive = tty_flag;
1875         char *proto = NULL, *data = NULL;
1876
1877         if (!success)
1878                 return; /* No need for error message, channels code sens one */
1879
1880         display = getenv("DISPLAY");
1881         if (display == NULL && options.forward_x11)
1882                 debug("X11 forwarding requested but DISPLAY not set");
1883         if (options.forward_x11 && client_x11_get_proto(display,
1884             options.xauth_location, options.forward_x11_trusted,
1885             options.forward_x11_timeout, &proto, &data) == 0) {
1886                 /* Request forwarding with authentication spoofing. */
1887                 debug("Requesting X11 forwarding with authentication "
1888                     "spoofing.");
1889                 x11_request_forwarding_with_spoofing(id, display, proto,
1890                     data, 1);
1891                 client_expect_confirm(id, "X11 forwarding", CONFIRM_WARN);
1892                 /* XXX exit_on_forward_failure */
1893                 interactive = 1;
1894         }
1895
1896         check_agent_present();
1897         if (options.forward_agent) {
1898                 debug("Requesting authentication agent forwarding.");
1899                 channel_request_start(id, "auth-agent-req@openssh.com", 0);
1900                 packet_send();
1901         }
1902
1903         /* Tell the packet module whether this is an interactive session. */
1904         packet_set_interactive(interactive,
1905             options.ip_qos_interactive, options.ip_qos_bulk);
1906
1907         client_session2_setup(id, tty_flag, subsystem_flag, getenv("TERM"),
1908             NULL, fileno(stdin), &command, environ);
1909 }
1910
1911 /* open new channel for a session */
1912 static int
1913 ssh_session2_open(void)
1914 {
1915         Channel *c;
1916         int window, packetmax, in, out, err;
1917
1918         if (stdin_null_flag) {
1919                 in = open(_PATH_DEVNULL, O_RDONLY);
1920         } else {
1921                 in = dup(STDIN_FILENO);
1922         }
1923         out = dup(STDOUT_FILENO);
1924         err = dup(STDERR_FILENO);
1925
1926         if (in < 0 || out < 0 || err < 0)
1927                 fatal("dup() in/out/err failed");
1928
1929         /* enable nonblocking unless tty */
1930         if (!isatty(in))
1931                 set_nonblock(in);
1932         if (!isatty(out))
1933                 set_nonblock(out);
1934         if (!isatty(err))
1935                 set_nonblock(err);
1936
1937         window = CHAN_SES_WINDOW_DEFAULT;
1938         packetmax = CHAN_SES_PACKET_DEFAULT;
1939         if (tty_flag) {
1940                 window >>= 1;
1941                 packetmax >>= 1;
1942         }
1943         c = channel_new(
1944             "session", SSH_CHANNEL_OPENING, in, out, err,
1945             window, packetmax, CHAN_EXTENDED_WRITE,
1946             "client-session", /*nonblock*/0);
1947
1948         debug3("ssh_session2_open: channel_new: %d", c->self);
1949
1950         channel_send_open(c->self);
1951         if (!no_shell_flag)
1952                 channel_register_open_confirm(c->self,
1953                     ssh_session2_setup, NULL);
1954
1955         return c->self;
1956 }
1957
1958 static int
1959 ssh_session2(void)
1960 {
1961         int id = -1;
1962
1963         /* XXX should be pre-session */
1964         if (!options.control_persist)
1965                 ssh_init_stdio_forwarding();
1966         ssh_init_forwarding();
1967
1968         /* Start listening for multiplex clients */
1969         muxserver_listen();
1970
1971         /*
1972          * If we are in control persist mode and have a working mux listen
1973          * socket, then prepare to background ourselves and have a foreground
1974          * client attach as a control slave.
1975          * NB. we must save copies of the flags that we override for
1976          * the backgrounding, since we defer attachment of the slave until
1977          * after the connection is fully established (in particular,
1978          * async rfwd replies have been received for ExitOnForwardFailure).
1979          */
1980         if (options.control_persist && muxserver_sock != -1) {
1981                 ostdin_null_flag = stdin_null_flag;
1982                 ono_shell_flag = no_shell_flag;
1983                 orequest_tty = options.request_tty;
1984                 otty_flag = tty_flag;
1985                 stdin_null_flag = 1;
1986                 no_shell_flag = 1;
1987                 tty_flag = 0;
1988                 if (!fork_after_authentication_flag)
1989                         need_controlpersist_detach = 1;
1990                 fork_after_authentication_flag = 1;
1991         }
1992         /*
1993          * ControlPersist mux listen socket setup failed, attempt the
1994          * stdio forward setup that we skipped earlier.
1995          */
1996         if (options.control_persist && muxserver_sock == -1)
1997                 ssh_init_stdio_forwarding();
1998
1999         if (!no_shell_flag || (datafellows & SSH_BUG_DUMMYCHAN))
2000                 id = ssh_session2_open();
2001         else {
2002                 packet_set_interactive(
2003                     options.control_master == SSHCTL_MASTER_NO,
2004                     options.ip_qos_interactive, options.ip_qos_bulk);
2005         }
2006
2007         /* If we don't expect to open a new session, then disallow it */
2008         if (options.control_master == SSHCTL_MASTER_NO &&
2009             (datafellows & SSH_NEW_OPENSSH)) {
2010                 debug("Requesting no-more-sessions@openssh.com");
2011                 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2012                 packet_put_cstring("no-more-sessions@openssh.com");
2013                 packet_put_char(0);
2014                 packet_send();
2015         }
2016
2017         /* Execute a local command */
2018         if (options.local_command != NULL &&
2019             options.permit_local_command)
2020                 ssh_local_cmd(options.local_command);
2021
2022         /*
2023          * If requested and we are not interested in replies to remote
2024          * forwarding requests, then let ssh continue in the background.
2025          */
2026         if (fork_after_authentication_flag) {
2027                 if (options.exit_on_forward_failure &&
2028                     options.num_remote_forwards > 0) {
2029                         debug("deferring postauth fork until remote forward "
2030                             "confirmation received");
2031                 } else
2032                         fork_postauth();
2033         }
2034
2035         return client_loop(tty_flag, tty_flag ?
2036             options.escape_char : SSH_ESCAPECHAR_NONE, id);
2037 }
2038
2039 /* Loads all IdentityFile and CertificateFile keys */
2040 static void
2041 load_public_identity_files(void)
2042 {
2043         char *filename, *cp, thishost[NI_MAXHOST];
2044         char *pwdir = NULL, *pwname = NULL;
2045         Key *public;
2046         struct passwd *pw;
2047         int i;
2048         u_int n_ids, n_certs;
2049         char *identity_files[SSH_MAX_IDENTITY_FILES];
2050         Key *identity_keys[SSH_MAX_IDENTITY_FILES];
2051         char *certificate_files[SSH_MAX_CERTIFICATE_FILES];
2052         struct sshkey *certificates[SSH_MAX_CERTIFICATE_FILES];
2053 #ifdef ENABLE_PKCS11
2054         Key **keys;
2055         int nkeys;
2056 #endif /* PKCS11 */
2057
2058         n_ids = n_certs = 0;
2059         memset(identity_files, 0, sizeof(identity_files));
2060         memset(identity_keys, 0, sizeof(identity_keys));
2061         memset(certificate_files, 0, sizeof(certificate_files));
2062         memset(certificates, 0, sizeof(certificates));
2063
2064 #ifdef ENABLE_PKCS11
2065         if (options.pkcs11_provider != NULL &&
2066             options.num_identity_files < SSH_MAX_IDENTITY_FILES &&
2067             (pkcs11_init(!options.batch_mode) == 0) &&
2068             (nkeys = pkcs11_add_provider(options.pkcs11_provider, NULL,
2069             &keys)) > 0) {
2070                 for (i = 0; i < nkeys; i++) {
2071                         if (n_ids >= SSH_MAX_IDENTITY_FILES) {
2072                                 key_free(keys[i]);
2073                                 continue;
2074                         }
2075                         identity_keys[n_ids] = keys[i];
2076                         identity_files[n_ids] =
2077                             xstrdup(options.pkcs11_provider); /* XXX */
2078                         n_ids++;
2079                 }
2080                 free(keys);
2081         }
2082 #endif /* ENABLE_PKCS11 */
2083         if ((pw = getpwuid(original_real_uid)) == NULL)
2084                 fatal("load_public_identity_files: getpwuid failed");
2085         pwname = xstrdup(pw->pw_name);
2086         pwdir = xstrdup(pw->pw_dir);
2087         if (gethostname(thishost, sizeof(thishost)) == -1)
2088                 fatal("load_public_identity_files: gethostname: %s",
2089                     strerror(errno));
2090         for (i = 0; i < options.num_identity_files; i++) {
2091                 if (n_ids >= SSH_MAX_IDENTITY_FILES ||
2092                     strcasecmp(options.identity_files[i], "none") == 0) {
2093                         free(options.identity_files[i]);
2094                         options.identity_files[i] = NULL;
2095                         continue;
2096                 }
2097                 cp = tilde_expand_filename(options.identity_files[i],
2098                     original_real_uid);
2099                 filename = percent_expand(cp, "d", pwdir,
2100                     "u", pwname, "l", thishost, "h", host,
2101                     "r", options.user, (char *)NULL);
2102                 free(cp);
2103                 public = key_load_public(filename, NULL);
2104                 debug("identity file %s type %d", filename,
2105                     public ? public->type : -1);
2106                 free(options.identity_files[i]);
2107                 identity_files[n_ids] = filename;
2108                 identity_keys[n_ids] = public;
2109
2110                 if (++n_ids >= SSH_MAX_IDENTITY_FILES)
2111                         continue;
2112
2113                 /*
2114                  * If no certificates have been explicitly listed then try
2115                  * to add the default certificate variant too.
2116                  */
2117                 if (options.num_certificate_files != 0)
2118                         continue;
2119                 xasprintf(&cp, "%s-cert", filename);
2120                 public = key_load_public(cp, NULL);
2121                 debug("identity file %s type %d", cp,
2122                     public ? public->type : -1);
2123                 if (public == NULL) {
2124                         free(cp);
2125                         continue;
2126                 }
2127                 if (!key_is_cert(public)) {
2128                         debug("%s: key %s type %s is not a certificate",
2129                             __func__, cp, key_type(public));
2130                         key_free(public);
2131                         free(cp);
2132                         continue;
2133                 }
2134                 identity_keys[n_ids] = public;
2135                 identity_files[n_ids] = cp;
2136                 n_ids++;
2137         }
2138
2139         if (options.num_certificate_files > SSH_MAX_CERTIFICATE_FILES)
2140                 fatal("%s: too many certificates", __func__);
2141         for (i = 0; i < options.num_certificate_files; i++) {
2142                 cp = tilde_expand_filename(options.certificate_files[i],
2143                     original_real_uid);
2144                 filename = percent_expand(cp, "d", pwdir,
2145                     "u", pwname, "l", thishost, "h", host,
2146                     "r", options.user, (char *)NULL);
2147                 free(cp);
2148
2149                 public = key_load_public(filename, NULL);
2150                 debug("certificate file %s type %d", filename,
2151                     public ? public->type : -1);
2152                 free(options.certificate_files[i]);
2153                 options.certificate_files[i] = NULL;
2154                 if (public == NULL) {
2155                         free(filename);
2156                         continue;
2157                 }
2158                 if (!key_is_cert(public)) {
2159                         debug("%s: key %s type %s is not a certificate",
2160                             __func__, filename, key_type(public));
2161                         key_free(public);
2162                         free(filename);
2163                         continue;
2164                 }
2165                 certificate_files[n_certs] = filename;
2166                 certificates[n_certs] = public;
2167                 ++n_certs;
2168         }
2169
2170         options.num_identity_files = n_ids;
2171         memcpy(options.identity_files, identity_files, sizeof(identity_files));
2172         memcpy(options.identity_keys, identity_keys, sizeof(identity_keys));
2173
2174         options.num_certificate_files = n_certs;
2175         memcpy(options.certificate_files,
2176             certificate_files, sizeof(certificate_files));
2177         memcpy(options.certificates, certificates, sizeof(certificates));
2178
2179         explicit_bzero(pwname, strlen(pwname));
2180         free(pwname);
2181         explicit_bzero(pwdir, strlen(pwdir));
2182         free(pwdir);
2183 }
2184
2185 static void
2186 main_sigchld_handler(int sig)
2187 {
2188         int save_errno = errno;
2189         pid_t pid;
2190         int status;
2191
2192         while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
2193             (pid < 0 && errno == EINTR))
2194                 ;
2195
2196         signal(sig, main_sigchld_handler);
2197         errno = save_errno;
2198 }