crypto/openssh/ssh.c

   1 /* $OpenBSD: ssh.c,v 1.490 2018/07/27 05:34:42 dtucker 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 "ssh2.h"
  86 #include "canohost.h"
  87 #include "compat.h"
  88 #include "cipher.h"
  89 #include "digest.h"
  90 #include "packet.h"
  91 #include "sshbuf.h"
  92 #include "channels.h"
  93 #include "sshkey.h"
  94 #include "authfd.h"
  95 #include "authfile.h"
  96 #include "pathnames.h"
  97 #include "dispatch.h"
  98 #include "clientloop.h"
  99 #include "log.h"
 100 #include "misc.h"
 101 #include "readconf.h"
 102 #include "sshconnect.h"
 103 #include "kex.h"
 104 #include "mac.h"
 105 #include "sshpty.h"
 106 #include "match.h"
 107 #include "msg.h"
 108 #include "version.h"
 109 #include "ssherr.h"
 110 #include "myproposal.h"
 111 #include "utf8.h"
 112
 113 #ifdef ENABLE_PKCS11
 114 #include "ssh-pkcs11.h"
 115 #endif
 116
 117 extern char *__progname;
 118
 119 /* Saves a copy of argv for setproctitle emulation */
 120 #ifndef HAVE_SETPROCTITLE
 121 static char **saved_av;
 122 #endif
 123
 124 /* Flag indicating whether debug mode is on.  May be set on the command line. */
 125 int debug_flag = 0;
 126
 127 /* Flag indicating whether a tty should be requested */
 128 int tty_flag = 0;
 129
 130 /* don't exec a shell */
 131 int no_shell_flag = 0;
 132
 133 /*
 134  * Flag indicating that nothing should be read from stdin.  This can be set
 135  * on the command line.
 136  */
 137 int stdin_null_flag = 0;
 138
 139 /*
 140  * Flag indicating that the current process should be backgrounded and
 141  * a new slave launched in the foreground for ControlPersist.
 142  */
 143 int need_controlpersist_detach = 0;
 144
 145 /* Copies of flags for ControlPersist foreground slave */
 146 int ostdin_null_flag, ono_shell_flag, otty_flag, orequest_tty;
 147
 148 /*
 149  * Flag indicating that ssh should fork after authentication.  This is useful
 150  * so that the passphrase can be entered manually, and then ssh goes to the
 151  * background.
 152  */
 153 int fork_after_authentication_flag = 0;
 154
 155 /*
 156  * General data structure for command line options and options configurable
 157  * in configuration files.  See readconf.h.
 158  */
 159 Options options;
 160
 161 /* optional user configfile */
 162 char *config = NULL;
 163
 164 /*
 165  * Name of the host we are connecting to.  This is the name given on the
 166  * command line, or the HostName specified for the user-supplied name in a
 167  * configuration file.
 168  */
 169 char *host;
 170
 171 /* Various strings used to to percent_expand() arguments */
 172 static char thishost[NI_MAXHOST], shorthost[NI_MAXHOST], portstr[NI_MAXSERV];
 173 static char uidstr[32], *host_arg, *conn_hash_hex;
 174
 175 /* socket address the host resolves to */
 176 struct sockaddr_storage hostaddr;
 177
 178 /* Private host keys. */
 179 Sensitive sensitive_data;
 180
 181 /* command to be executed */
 182 struct sshbuf *command;
 183
 184 /* Should we execute a command or invoke a subsystem? */
 185 int subsystem_flag = 0;
 186
 187 /* # of replies received for global requests */
 188 static int remote_forward_confirms_received = 0;
 189
 190 /* mux.c */
 191 extern int muxserver_sock;
 192 extern u_int muxclient_command;
 193
 194 /* Prints a help message to the user.  This function never returns. */
 195
 196 static void
 197 usage(void)
 198 {
 199         fprintf(stderr,
 200 "usage: ssh [-46AaCfGgKkMNnqsTtVvXxYy] [-B bind_interface]\n"
 201 "           [-b bind_address] [-c cipher_spec] [-D [bind_address:]port]\n"
 202 "           [-E log_file] [-e escape_char] [-F configfile] [-I pkcs11]\n"
 203 "           [-i identity_file] [-J [user@]host[:port]] [-L address]\n"
 204 "           [-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port]\n"
 205 "           [-Q query_option] [-R address] [-S ctl_path] [-W host:port]\n"
 206 "           [-w local_tun[:remote_tun]] destination [command]\n"
 207         );
 208         exit(255);
 209 }
 210
 211 static int ssh_session2(struct ssh *, struct passwd *);
 212 static void load_public_identity_files(struct passwd *);
 213 static void main_sigchld_handler(int);
 214
 215 /* ~/ expand a list of paths. NB. assumes path[n] is heap-allocated. */
 216 static void
 217 tilde_expand_paths(char **paths, u_int num_paths)
 218 {
 219         u_int i;
 220         char *cp;
 221
 222         for (i = 0; i < num_paths; i++) {
 223                 cp = tilde_expand_filename(paths[i], getuid());
 224                 free(paths[i]);
 225                 paths[i] = cp;
 226         }
 227 }
 228
 229 /*
 230  * Attempt to resolve a host name / port to a set of addresses and
 231  * optionally return any CNAMEs encountered along the way.
 232  * Returns NULL on failure.
 233  * NB. this function must operate with a options having undefined members.
 234  */
 235 static struct addrinfo *
 236 resolve_host(const char *name, int port, int logerr, char *cname, size_t clen)
 237 {
 238         char strport[NI_MAXSERV];
 239         struct addrinfo hints, *res;
 240         int gaierr, loglevel = SYSLOG_LEVEL_DEBUG1;
 241
 242         if (port <= 0)
 243                 port = default_ssh_port();
 244
 245         snprintf(strport, sizeof strport, "%d", port);
 246         memset(&hints, 0, sizeof(hints));
 247         hints.ai_family = options.address_family == -1 ?
 248             AF_UNSPEC : options.address_family;
 249         hints.ai_socktype = SOCK_STREAM;
 250         if (cname != NULL)
 251                 hints.ai_flags = AI_CANONNAME;
 252         if ((gaierr = getaddrinfo(name, strport, &hints, &res)) != 0) {
 253                 if (logerr || (gaierr != EAI_NONAME && gaierr != EAI_NODATA))
 254                         loglevel = SYSLOG_LEVEL_ERROR;
 255                 do_log2(loglevel, "%s: Could not resolve hostname %.100s: %s",
 256                     __progname, name, ssh_gai_strerror(gaierr));
 257                 return NULL;
 258         }
 259         if (cname != NULL && res->ai_canonname != NULL) {
 260                 if (strlcpy(cname, res->ai_canonname, clen) >= clen) {
 261                         error("%s: host \"%s\" cname \"%s\" too long (max %lu)",
 262                             __func__, name,  res->ai_canonname, (u_long)clen);
 263                         if (clen > 0)
 264                                 *cname = '\0';
 265                 }
 266         }
 267         return res;
 268 }
 269
 270 /* Returns non-zero if name can only be an address and not a hostname */
 271 static int
 272 is_addr_fast(const char *name)
 273 {
 274         return (strchr(name, '%') != NULL || strchr(name, ':') != NULL ||
 275             strspn(name, "0123456789.") == strlen(name));
 276 }
 277
 278 /* Returns non-zero if name represents a valid, single address */
 279 static int
 280 is_addr(const char *name)
 281 {
 282         char strport[NI_MAXSERV];
 283         struct addrinfo hints, *res;
 284
 285         if (is_addr_fast(name))
 286                 return 1;
 287
 288         snprintf(strport, sizeof strport, "%u", default_ssh_port());
 289         memset(&hints, 0, sizeof(hints));
 290         hints.ai_family = options.address_family == -1 ?
 291             AF_UNSPEC : options.address_family;
 292         hints.ai_socktype = SOCK_STREAM;
 293         hints.ai_flags = AI_NUMERICHOST|AI_NUMERICSERV;
 294         if (getaddrinfo(name, strport, &hints, &res) != 0)
 295                 return 0;
 296         if (res == NULL || res->ai_next != NULL) {
 297                 freeaddrinfo(res);
 298                 return 0;
 299         }
 300         freeaddrinfo(res);
 301         return 1;
 302 }
 303
 304 /*
 305  * Attempt to resolve a numeric host address / port to a single address.
 306  * Returns a canonical address string.
 307  * Returns NULL on failure.
 308  * NB. this function must operate with a options having undefined members.
 309  */
 310 static struct addrinfo *
 311 resolve_addr(const char *name, int port, char *caddr, size_t clen)
 312 {
 313         char addr[NI_MAXHOST], strport[NI_MAXSERV];
 314         struct addrinfo hints, *res;
 315         int gaierr;
 316
 317         if (port <= 0)
 318                 port = default_ssh_port();
 319         snprintf(strport, sizeof strport, "%u", port);
 320         memset(&hints, 0, sizeof(hints));
 321         hints.ai_family = options.address_family == -1 ?
 322             AF_UNSPEC : options.address_family;
 323         hints.ai_socktype = SOCK_STREAM;
 324         hints.ai_flags = AI_NUMERICHOST|AI_NUMERICSERV;
 325         if ((gaierr = getaddrinfo(name, strport, &hints, &res)) != 0) {
 326                 debug2("%s: could not resolve name %.100s as address: %s",
 327                     __func__, name, ssh_gai_strerror(gaierr));
 328                 return NULL;
 329         }
 330         if (res == NULL) {
 331                 debug("%s: getaddrinfo %.100s returned no addresses",
 332                  __func__, name);
 333                 return NULL;
 334         }
 335         if (res->ai_next != NULL) {
 336                 debug("%s: getaddrinfo %.100s returned multiple addresses",
 337                     __func__, name);
 338                 goto fail;
 339         }
 340         if ((gaierr = getnameinfo(res->ai_addr, res->ai_addrlen,
 341             addr, sizeof(addr), NULL, 0, NI_NUMERICHOST)) != 0) {
 342                 debug("%s: Could not format address for name %.100s: %s",
 343                     __func__, name, ssh_gai_strerror(gaierr));
 344                 goto fail;
 345         }
 346         if (strlcpy(caddr, addr, clen) >= clen) {
 347                 error("%s: host \"%s\" addr \"%s\" too long (max %lu)",
 348                     __func__, name,  addr, (u_long)clen);
 349                 if (clen > 0)
 350                         *caddr = '\0';
 351  fail:
 352                 freeaddrinfo(res);
 353                 return NULL;
 354         }
 355         return res;
 356 }
 357
 358 /*
 359  * Check whether the cname is a permitted replacement for the hostname
 360  * and perform the replacement if it is.
 361  * NB. this function must operate with a options having undefined members.
 362  */
 363 static int
 364 check_follow_cname(int direct, char **namep, const char *cname)
 365 {
 366         int i;
 367         struct allowed_cname *rule;
 368
 369         if (*cname == '\0' || options.num_permitted_cnames == 0 ||
 370             strcmp(*namep, cname) == 0)
 371                 return 0;
 372         if (options.canonicalize_hostname == SSH_CANONICALISE_NO)
 373                 return 0;
 374         /*
 375          * Don't attempt to canonicalize names that will be interpreted by
 376          * a proxy or jump host unless the user specifically requests so.
 377          */
 378         if (!direct &&
 379             options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS)
 380                 return 0;
 381         debug3("%s: check \"%s\" CNAME \"%s\"", __func__, *namep, cname);
 382         for (i = 0; i < options.num_permitted_cnames; i++) {
 383                 rule = options.permitted_cnames + i;
 384                 if (match_pattern_list(*namep, rule->source_list, 1) != 1 ||
 385                     match_pattern_list(cname, rule->target_list, 1) != 1)
 386                         continue;
 387                 verbose("Canonicalized DNS aliased hostname "
 388                     "\"%s\" => \"%s\"", *namep, cname);
 389                 free(*namep);
 390                 *namep = xstrdup(cname);
 391                 return 1;
 392         }
 393         return 0;
 394 }
 395
 396 /*
 397  * Attempt to resolve the supplied hostname after applying the user's
 398  * canonicalization rules. Returns the address list for the host or NULL
 399  * if no name was found after canonicalization.
 400  * NB. this function must operate with a options having undefined members.
 401  */
 402 static struct addrinfo *
 403 resolve_canonicalize(char **hostp, int port)
 404 {
 405         int i, direct, ndots;
 406         char *cp, *fullhost, newname[NI_MAXHOST];
 407         struct addrinfo *addrs;
 408
 409         /*
 410          * Attempt to canonicalise addresses, regardless of
 411          * whether hostname canonicalisation was requested
 412          */
 413         if ((addrs = resolve_addr(*hostp, port,
 414             newname, sizeof(newname))) != NULL) {
 415                 debug2("%s: hostname %.100s is address", __func__, *hostp);
 416                 if (strcasecmp(*hostp, newname) != 0) {
 417                         debug2("%s: canonicalised address \"%s\" => \"%s\"",
 418                             __func__, *hostp, newname);
 419                         free(*hostp);
 420                         *hostp = xstrdup(newname);
 421                 }
 422                 return addrs;
 423         }
 424
 425         /*
 426          * If this looks like an address but didn't parse as one, it might
 427          * be an address with an invalid interface scope. Skip further
 428          * attempts at canonicalisation.
 429          */
 430         if (is_addr_fast(*hostp)) {
 431                 debug("%s: hostname %.100s is an unrecognised address",
 432                     __func__, *hostp);
 433                 return NULL;
 434         }
 435
 436         if (options.canonicalize_hostname == SSH_CANONICALISE_NO)
 437                 return NULL;
 438
 439         /*
 440          * Don't attempt to canonicalize names that will be interpreted by
 441          * a proxy unless the user specifically requests so.
 442          */
 443         direct = option_clear_or_none(options.proxy_command) &&
 444             options.jump_host == NULL;
 445         if (!direct &&
 446             options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS)
 447                 return NULL;
 448
 449         /* If domain name is anchored, then resolve it now */
 450         if ((*hostp)[strlen(*hostp) - 1] == '.') {
 451                 debug3("%s: name is fully qualified", __func__);
 452                 fullhost = xstrdup(*hostp);
 453                 if ((addrs = resolve_host(fullhost, port, 0,
 454                     newname, sizeof(newname))) != NULL)
 455                         goto found;
 456                 free(fullhost);
 457                 goto notfound;
 458         }
 459
 460         /* Don't apply canonicalization to sufficiently-qualified hostnames */
 461         ndots = 0;
 462         for (cp = *hostp; *cp != '\0'; cp++) {
 463                 if (*cp == '.')
 464                         ndots++;
 465         }
 466         if (ndots > options.canonicalize_max_dots) {
 467                 debug3("%s: not canonicalizing hostname \"%s\" (max dots %d)",
 468                     __func__, *hostp, options.canonicalize_max_dots);
 469                 return NULL;
 470         }
 471         /* Attempt each supplied suffix */
 472         for (i = 0; i < options.num_canonical_domains; i++) {
 473                 *newname = '\0';
 474                 xasprintf(&fullhost, "%s.%s.", *hostp,
 475                     options.canonical_domains[i]);
 476                 debug3("%s: attempting \"%s\" => \"%s\"", __func__,
 477                     *hostp, fullhost);
 478                 if ((addrs = resolve_host(fullhost, port, 0,
 479                     newname, sizeof(newname))) == NULL) {
 480                         free(fullhost);
 481                         continue;
 482                 }
 483  found:
 484                 /* Remove trailing '.' */
 485                 fullhost[strlen(fullhost) - 1] = '\0';
 486                 /* Follow CNAME if requested */
 487                 if (!check_follow_cname(direct, &fullhost, newname)) {
 488                         debug("Canonicalized hostname \"%s\" => \"%s\"",
 489                             *hostp, fullhost);
 490                 }
 491                 free(*hostp);
 492                 *hostp = fullhost;
 493                 return addrs;
 494         }
 495  notfound:
 496         if (!options.canonicalize_fallback_local)
 497                 fatal("%s: Could not resolve host \"%s\"", __progname, *hostp);
 498         debug2("%s: host %s not found in any suffix", __func__, *hostp);
 499         return NULL;
 500 }
 501
 502 /*
 503  * Check the result of hostkey loading, ignoring some errors and
 504  * fatal()ing for others.
 505  */
 506 static void
 507 check_load(int r, const char *path, const char *message)
 508 {
 509         switch (r) {
 510         case 0:
 511                 break;
 512         case SSH_ERR_INTERNAL_ERROR:
 513         case SSH_ERR_ALLOC_FAIL:
 514                 fatal("load %s \"%s\": %s", message, path, ssh_err(r));
 515         case SSH_ERR_SYSTEM_ERROR:
 516                 /* Ignore missing files */
 517                 if (errno == ENOENT)
 518                         break;
 519                 /* FALLTHROUGH */
 520         default:
 521                 error("load %s \"%s\": %s", message, path, ssh_err(r));
 522                 break;
 523         }
 524 }
 525
 526 /*
 527  * Read per-user configuration file.  Ignore the system wide config
 528  * file if the user specifies a config file on the command line.
 529  */
 530 static void
 531 process_config_files(const char *host_name, struct passwd *pw, int post_canon)
 532 {
 533         char buf[PATH_MAX];
 534         int r;
 535
 536         if (config != NULL) {
 537                 if (strcasecmp(config, "none") != 0 &&
 538                     !read_config_file(config, pw, host, host_name, &options,
 539                     SSHCONF_USERCONF | (post_canon ? SSHCONF_POSTCANON : 0)))
 540                         fatal("Can't open user config file %.100s: "
 541                             "%.100s", config, strerror(errno));
 542         } else {
 543                 r = snprintf(buf, sizeof buf, "%s/%s", pw->pw_dir,
 544                     _PATH_SSH_USER_CONFFILE);
 545                 if (r > 0 && (size_t)r < sizeof(buf))
 546                         (void)read_config_file(buf, pw, host, host_name,
 547                             &options, SSHCONF_CHECKPERM | SSHCONF_USERCONF |
 548                             (post_canon ? SSHCONF_POSTCANON : 0));
 549
 550                 /* Read systemwide configuration file after user config. */
 551                 (void)read_config_file(_PATH_HOST_CONFIG_FILE, pw,
 552                     host, host_name, &options,
 553                     post_canon ? SSHCONF_POSTCANON : 0);
 554         }
 555 }
 556
 557 /* Rewrite the port number in an addrinfo list of addresses */
 558 static void
 559 set_addrinfo_port(struct addrinfo *addrs, int port)
 560 {
 561         struct addrinfo *addr;
 562
 563         for (addr = addrs; addr != NULL; addr = addr->ai_next) {
 564                 switch (addr->ai_family) {
 565                 case AF_INET:
 566                         ((struct sockaddr_in *)addr->ai_addr)->
 567                             sin_port = htons(port);
 568                         break;
 569                 case AF_INET6:
 570                         ((struct sockaddr_in6 *)addr->ai_addr)->
 571                             sin6_port = htons(port);
 572                         break;
 573                 }
 574         }
 575 }
 576
 577 /*
 578  * Main program for the ssh client.
 579  */
 580 int
 581 main(int ac, char **av)
 582 {
 583         struct ssh *ssh = NULL;
 584         int i, r, opt, exit_status, use_syslog, direct, timeout_ms;
 585         int was_addr, config_test = 0, opt_terminated = 0;
 586         char *p, *cp, *line, *argv0, buf[PATH_MAX], *logfile;
 587         char cname[NI_MAXHOST];
 588         struct stat st;
 589         struct passwd *pw;
 590         extern int optind, optreset;
 591         extern char *optarg;
 592         struct Forward fwd;
 593         struct addrinfo *addrs = NULL;
 594         struct ssh_digest_ctx *md;
 595         u_char conn_hash[SSH_DIGEST_MAX_LENGTH];
 596
 597         ssh_malloc_init();      /* must be called before any mallocs */
 598         /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
 599         sanitise_stdfd();
 600
 601         __progname = ssh_get_progname(av[0]);
 602
 603 #ifndef HAVE_SETPROCTITLE
 604         /* Prepare for later setproctitle emulation */
 605         /* Save argv so it isn't clobbered by setproctitle() emulation */
 606         saved_av = xcalloc(ac + 1, sizeof(*saved_av));
 607         for (i = 0; i < ac; i++)
 608                 saved_av[i] = xstrdup(av[i]);
 609         saved_av[i] = NULL;
 610         compat_init_setproctitle(ac, av);
 611         av = saved_av;
 612 #endif
 613
 614         /*
 615          * Discard other fds that are hanging around. These can cause problem
 616          * with backgrounded ssh processes started by ControlPersist.
 617          */
 618         closefrom(STDERR_FILENO + 1);
 619
 620         /* Get user data. */
 621         pw = getpwuid(getuid());
 622         if (!pw) {
 623                 logit("No user exists for uid %lu", (u_long)getuid());
 624                 exit(255);
 625         }
 626         /* Take a copy of the returned structure. */
 627         pw = pwcopy(pw);
 628
 629         /*
 630          * Set our umask to something reasonable, as some files are created
 631          * with the default umask.  This will make them world-readable but
 632          * writable only by the owner, which is ok for all files for which we
 633          * don't set the modes explicitly.
 634          */
 635         umask(022);
 636
 637         msetlocale();
 638
 639         /*
 640          * Initialize option structure to indicate that no values have been
 641          * set.
 642          */
 643         initialize_options(&options);
 644
 645         /*
 646          * Prepare main ssh transport/connection structures
 647          */
 648         if ((ssh = ssh_alloc_session_state()) == NULL)
 649                 fatal("Couldn't allocate session state");
 650         channel_init_channels(ssh);
 651         active_state = ssh; /* XXX legacy API compat */
 652
 653         /* Parse command-line arguments. */
 654         host = NULL;
 655         use_syslog = 0;
 656         logfile = NULL;
 657         argv0 = av[0];
 658
 659  again:
 660         while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx"
 661             "AB:CD:E:F:GI:J:KL:MNO:PQ:R:S:TVw:W:XYy")) != -1) {
 662                 switch (opt) {
 663                 case '1':
 664                         fatal("SSH protocol v.1 is no longer supported");
 665                         break;
 666                 case '2':
 667                         /* Ignored */
 668                         break;
 669                 case '4':
 670                         options.address_family = AF_INET;
 671                         break;
 672                 case '6':
 673                         options.address_family = AF_INET6;
 674                         break;
 675                 case 'n':
 676                         stdin_null_flag = 1;
 677                         break;
 678                 case 'f':
 679                         fork_after_authentication_flag = 1;
 680                         stdin_null_flag = 1;
 681                         break;
 682                 case 'x':
 683                         options.forward_x11 = 0;
 684                         break;
 685                 case 'X':
 686                         options.forward_x11 = 1;
 687                         break;
 688                 case 'y':
 689                         use_syslog = 1;
 690                         break;
 691                 case 'E':
 692                         logfile = optarg;
 693                         break;
 694                 case 'G':
 695                         config_test = 1;
 696                         break;
 697                 case 'Y':
 698                         options.forward_x11 = 1;
 699                         options.forward_x11_trusted = 1;
 700                         break;
 701                 case 'g':
 702                         options.fwd_opts.gateway_ports = 1;
 703                         break;
 704                 case 'O':
 705                         if (options.stdio_forward_host != NULL)
 706                                 fatal("Cannot specify multiplexing "
 707                                     "command with -W");
 708                         else if (muxclient_command != 0)
 709                                 fatal("Multiplexing command already specified");
 710                         if (strcmp(optarg, "check") == 0)
 711                                 muxclient_command = SSHMUX_COMMAND_ALIVE_CHECK;
 712                         else if (strcmp(optarg, "forward") == 0)
 713                                 muxclient_command = SSHMUX_COMMAND_FORWARD;
 714                         else if (strcmp(optarg, "exit") == 0)
 715                                 muxclient_command = SSHMUX_COMMAND_TERMINATE;
 716                         else if (strcmp(optarg, "stop") == 0)
 717                                 muxclient_command = SSHMUX_COMMAND_STOP;
 718                         else if (strcmp(optarg, "cancel") == 0)
 719                                 muxclient_command = SSHMUX_COMMAND_CANCEL_FWD;
 720                         else if (strcmp(optarg, "proxy") == 0)
 721                                 muxclient_command = SSHMUX_COMMAND_PROXY;
 722                         else
 723                                 fatal("Invalid multiplex command.");
 724                         break;
 725                 case 'P':       /* deprecated */
 726                         break;
 727                 case 'Q':
 728                         cp = NULL;
 729                         if (strcmp(optarg, "cipher") == 0)
 730                                 cp = cipher_alg_list('\n', 0);
 731                         else if (strcmp(optarg, "cipher-auth") == 0)
 732                                 cp = cipher_alg_list('\n', 1);
 733                         else if (strcmp(optarg, "mac") == 0)
 734                                 cp = mac_alg_list('\n');
 735                         else if (strcmp(optarg, "kex") == 0)
 736                                 cp = kex_alg_list('\n');
 737                         else if (strcmp(optarg, "key") == 0)
 738                                 cp = sshkey_alg_list(0, 0, 0, '\n');
 739                         else if (strcmp(optarg, "key-cert") == 0)
 740                                 cp = sshkey_alg_list(1, 0, 0, '\n');
 741                         else if (strcmp(optarg, "key-plain") == 0)
 742                                 cp = sshkey_alg_list(0, 1, 0, '\n');
 743                         else if (strcmp(optarg, "protocol-version") == 0) {
 744                                 cp = xstrdup("2");
 745                         }
 746                         if (cp == NULL)
 747                                 fatal("Unsupported query \"%s\"", optarg);
 748                         printf("%s\n", cp);
 749                         free(cp);
 750                         exit(0);
 751                         break;
 752                 case 'a':
 753                         options.forward_agent = 0;
 754                         break;
 755                 case 'A':
 756                         options.forward_agent = 1;
 757                         break;
 758                 case 'k':
 759                         options.gss_deleg_creds = 0;
 760                         break;
 761                 case 'K':
 762                         options.gss_authentication = 1;
 763                         options.gss_deleg_creds = 1;
 764                         break;
 765                 case 'i':
 766                         p = tilde_expand_filename(optarg, getuid());
 767                         if (stat(p, &st) < 0)
 768                                 fprintf(stderr, "Warning: Identity file %s "
 769                                     "not accessible: %s.\n", p,
 770                                     strerror(errno));
 771                         else
 772                                 add_identity_file(&options, NULL, p, 1);
 773                         free(p);
 774                         break;
 775                 case 'I':
 776 #ifdef ENABLE_PKCS11
 777                         free(options.pkcs11_provider);
 778                         options.pkcs11_provider = xstrdup(optarg);
 779 #else
 780                         fprintf(stderr, "no support for PKCS#11.\n");
 781 #endif
 782                         break;
 783                 case 'J':
 784                         if (options.jump_host != NULL)
 785                                 fatal("Only a single -J option permitted");
 786                         if (options.proxy_command != NULL)
 787                                 fatal("Cannot specify -J with ProxyCommand");
 788                         if (parse_jump(optarg, &options, 1) == -1)
 789                                 fatal("Invalid -J argument");
 790                         options.proxy_command = xstrdup("none");
 791                         break;
 792                 case 't':
 793                         if (options.request_tty == REQUEST_TTY_YES)
 794                                 options.request_tty = REQUEST_TTY_FORCE;
 795                         else
 796                                 options.request_tty = REQUEST_TTY_YES;
 797                         break;
 798                 case 'v':
 799                         if (debug_flag == 0) {
 800                                 debug_flag = 1;
 801                                 options.log_level = SYSLOG_LEVEL_DEBUG1;
 802                         } else {
 803                                 if (options.log_level < SYSLOG_LEVEL_DEBUG3) {
 804                                         debug_flag++;
 805                                         options.log_level++;
 806                                 }
 807                         }
 808                         break;
 809                 case 'V':
 810                         if (options.version_addendum &&
 811                             *options.version_addendum != '\0')
 812                                 fprintf(stderr, "%s %s, %s\n", SSH_RELEASE,
 813                                     options.version_addendum,
 814                                     OPENSSL_VERSION);
 815                         else
 816                                 fprintf(stderr, "%s, %s\n", SSH_RELEASE,
 817                                     OPENSSL_VERSION);
 818                         if (opt == 'V')
 819                                 exit(0);
 820                         break;
 821                 case 'w':
 822                         if (options.tun_open == -1)
 823                                 options.tun_open = SSH_TUNMODE_DEFAULT;
 824                         options.tun_local = a2tun(optarg, &options.tun_remote);
 825                         if (options.tun_local == SSH_TUNID_ERR) {
 826                                 fprintf(stderr,
 827                                     "Bad tun device '%s'\n", optarg);
 828                                 exit(255);
 829                         }
 830                         break;
 831                 case 'W':
 832                         if (options.stdio_forward_host != NULL)
 833                                 fatal("stdio forward already specified");
 834                         if (muxclient_command != 0)
 835                                 fatal("Cannot specify stdio forward with -O");
 836                         if (parse_forward(&fwd, optarg, 1, 0)) {
 837                                 options.stdio_forward_host = fwd.listen_host;
 838                                 options.stdio_forward_port = fwd.listen_port;
 839                                 free(fwd.connect_host);
 840                         } else {
 841                                 fprintf(stderr,
 842                                     "Bad stdio forwarding specification '%s'\n",
 843                                     optarg);
 844                                 exit(255);
 845                         }
 846                         options.request_tty = REQUEST_TTY_NO;
 847                         no_shell_flag = 1;
 848                         break;
 849                 case 'q':
 850                         options.log_level = SYSLOG_LEVEL_QUIET;
 851                         break;
 852                 case 'e':
 853                         if (optarg[0] == '^' && optarg[2] == 0 &&
 854                             (u_char) optarg[1] >= 64 &&
 855                             (u_char) optarg[1] < 128)
 856                                 options.escape_char = (u_char) optarg[1] & 31;
 857                         else if (strlen(optarg) == 1)
 858                                 options.escape_char = (u_char) optarg[0];
 859                         else if (strcmp(optarg, "none") == 0)
 860                                 options.escape_char = SSH_ESCAPECHAR_NONE;
 861                         else {
 862                                 fprintf(stderr, "Bad escape character '%s'.\n",
 863                                     optarg);
 864                                 exit(255);
 865                         }
 866                         break;
 867                 case 'c':
 868                         if (!ciphers_valid(*optarg == '+' ?
 869                             optarg + 1 : optarg)) {
 870                                 fprintf(stderr, "Unknown cipher type '%s'\n",
 871                                     optarg);
 872                                 exit(255);
 873                         }
 874                         free(options.ciphers);
 875                         options.ciphers = xstrdup(optarg);
 876                         break;
 877                 case 'm':
 878                         if (mac_valid(optarg)) {
 879                                 free(options.macs);
 880                                 options.macs = xstrdup(optarg);
 881                         } else {
 882                                 fprintf(stderr, "Unknown mac type '%s'\n",
 883                                     optarg);
 884                                 exit(255);
 885                         }
 886                         break;
 887                 case 'M':
 888                         if (options.control_master == SSHCTL_MASTER_YES)
 889                                 options.control_master = SSHCTL_MASTER_ASK;
 890                         else
 891                                 options.control_master = SSHCTL_MASTER_YES;
 892                         break;
 893                 case 'p':
 894                         if (options.port == -1) {
 895                                 options.port = a2port(optarg);
 896                                 if (options.port <= 0) {
 897                                         fprintf(stderr, "Bad port '%s'\n",
 898                                             optarg);
 899                                         exit(255);
 900                                 }
 901                         }
 902                         break;
 903                 case 'l':
 904                         if (options.user == NULL)
 905                                 options.user = optarg;
 906                         break;
 907
 908                 case 'L':
 909                         if (parse_forward(&fwd, optarg, 0, 0))
 910                                 add_local_forward(&options, &fwd);
 911                         else {
 912                                 fprintf(stderr,
 913                                     "Bad local forwarding specification '%s'\n",
 914                                     optarg);
 915                                 exit(255);
 916                         }
 917                         break;
 918
 919                 case 'R':
 920                         if (parse_forward(&fwd, optarg, 0, 1) ||
 921                             parse_forward(&fwd, optarg, 1, 1)) {
 922                                 add_remote_forward(&options, &fwd);
 923                         } else {
 924                                 fprintf(stderr,
 925                                     "Bad remote forwarding specification "
 926                                     "'%s'\n", optarg);
 927                                 exit(255);
 928                         }
 929                         break;
 930
 931                 case 'D':
 932                         if (parse_forward(&fwd, optarg, 1, 0)) {
 933                                 add_local_forward(&options, &fwd);
 934                         } else {
 935                                 fprintf(stderr,
 936                                     "Bad dynamic forwarding specification "
 937                                     "'%s'\n", optarg);
 938                                 exit(255);
 939                         }
 940                         break;
 941
 942                 case 'C':
 943                         options.compression = 1;
 944                         break;
 945                 case 'N':
 946                         no_shell_flag = 1;
 947                         options.request_tty = REQUEST_TTY_NO;
 948                         break;
 949                 case 'T':
 950                         options.request_tty = REQUEST_TTY_NO;
 951                         break;
 952                 case 'o':
 953                         line = xstrdup(optarg);
 954                         if (process_config_line(&options, pw,
 955                             host ? host : "", host ? host : "", line,
 956                             "command-line", 0, NULL, SSHCONF_USERCONF) != 0)
 957                                 exit(255);
 958                         free(line);
 959                         break;
 960                 case 's':
 961                         subsystem_flag = 1;
 962                         break;
 963                 case 'S':
 964                         free(options.control_path);
 965                         options.control_path = xstrdup(optarg);
 966                         break;
 967                 case 'b':
 968                         options.bind_address = optarg;
 969                         break;
 970                 case 'B':
 971                         options.bind_interface = optarg;
 972                         break;
 973                 case 'F':
 974                         config = optarg;
 975                         break;
 976                 default:
 977                         usage();
 978                 }
 979         }
 980
 981         if (optind > 1 && strcmp(av[optind - 1], "--") == 0)
 982                 opt_terminated = 1;
 983
 984         ac -= optind;
 985         av += optind;
 986
 987         if (ac > 0 && !host) {
 988                 int tport;
 989                 char *tuser;
 990                 switch (parse_ssh_uri(*av, &tuser, &host, &tport)) {
 991                 case -1:
 992                         usage();
 993                         break;
 994                 case 0:
 995                         if (options.user == NULL) {
 996                                 options.user = tuser;
 997                                 tuser = NULL;
 998                         }
 999                         free(tuser);
1000                         if (options.port == -1 && tport != -1)
1001                                 options.port = tport;
1002                         break;
1003                 default:
1004                         p = xstrdup(*av);
1005                         cp = strrchr(p, '@');
1006                         if (cp != NULL) {
1007                                 if (cp == p)
1008                                         usage();
1009                                 if (options.user == NULL) {
1010                                         options.user = p;
1011                                         p = NULL;
1012                                 }
1013                                 *cp++ = '\0';
1014                                 host = xstrdup(cp);
1015                                 free(p);
1016                         } else
1017                                 host = p;
1018                         break;
1019                 }
1020                 if (ac > 1 && !opt_terminated) {
1021                         optind = optreset = 1;
1022                         goto again;
1023                 }
1024                 ac--, av++;
1025         }
1026
1027         /* Check that we got a host name. */
1028         if (!host)
1029                 usage();
1030
1031         host_arg = xstrdup(host);
1032
1033 #ifdef WITH_OPENSSL
1034         OpenSSL_add_all_algorithms();
1035         ERR_load_crypto_strings();
1036 #endif
1037
1038         /* Initialize the command to execute on remote host. */
1039         if ((command = sshbuf_new()) == NULL)
1040                 fatal("sshbuf_new failed");
1041
1042         /*
1043          * Save the command to execute on the remote host in a buffer. There
1044          * is no limit on the length of the command, except by the maximum
1045          * packet size.  Also sets the tty flag if there is no command.
1046          */
1047         if (!ac) {
1048                 /* No command specified - execute shell on a tty. */
1049                 if (subsystem_flag) {
1050                         fprintf(stderr,
1051                             "You must specify a subsystem to invoke.\n");
1052                         usage();
1053                 }
1054         } else {
1055                 /* A command has been specified.  Store it into the buffer. */
1056                 for (i = 0; i < ac; i++) {
1057                         if ((r = sshbuf_putf(command, "%s%s",
1058                             i ? " " : "", av[i])) != 0)
1059                                 fatal("%s: buffer error: %s",
1060                                     __func__, ssh_err(r));
1061                 }
1062         }
1063
1064         /*
1065          * Initialize "log" output.  Since we are the client all output
1066          * goes to stderr unless otherwise specified by -y or -E.
1067          */
1068         if (use_syslog && logfile != NULL)
1069                 fatal("Can't specify both -y and -E");
1070         if (logfile != NULL)
1071                 log_redirect_stderr_to(logfile);
1072         log_init(argv0,
1073             options.log_level == SYSLOG_LEVEL_NOT_SET ?
1074             SYSLOG_LEVEL_INFO : options.log_level,
1075             options.log_facility == SYSLOG_FACILITY_NOT_SET ?
1076             SYSLOG_FACILITY_USER : options.log_facility,
1077             !use_syslog);
1078
1079         if (debug_flag)
1080                 /* version_addendum is always NULL at this point */
1081                 logit("%s, %s", SSH_RELEASE, OPENSSL_VERSION);
1082
1083         /* Parse the configuration files */
1084         process_config_files(host_arg, pw, 0);
1085
1086         /* Hostname canonicalisation needs a few options filled. */
1087         fill_default_options_for_canonicalization(&options);
1088
1089         /* If the user has replaced the hostname then take it into use now */
1090         if (options.hostname != NULL) {
1091                 /* NB. Please keep in sync with readconf.c:match_cfg_line() */
1092                 cp = percent_expand(options.hostname,
1093                     "h", host, (char *)NULL);
1094                 free(host);
1095                 host = cp;
1096                 free(options.hostname);
1097                 options.hostname = xstrdup(host);
1098         }
1099
1100         /* Don't lowercase addresses, they will be explicitly canonicalised */
1101         if ((was_addr = is_addr(host)) == 0)
1102                 lowercase(host);
1103
1104         /*
1105          * Try to canonicalize if requested by configuration or the
1106          * hostname is an address.
1107          */
1108         if (options.canonicalize_hostname != SSH_CANONICALISE_NO || was_addr)
1109                 addrs = resolve_canonicalize(&host, options.port);
1110
1111         /*
1112          * If CanonicalizePermittedCNAMEs have been specified but
1113          * other canonicalization did not happen (by not being requested
1114          * or by failing with fallback) then the hostname may still be changed
1115          * as a result of CNAME following.
1116          *
1117          * Try to resolve the bare hostname name using the system resolver's
1118          * usual search rules and then apply the CNAME follow rules.
1119          *
1120          * Skip the lookup if a ProxyCommand is being used unless the user
1121          * has specifically requested canonicalisation for this case via
1122          * CanonicalizeHostname=always
1123          */
1124         direct = option_clear_or_none(options.proxy_command) &&
1125             options.jump_host == NULL;
1126         if (addrs == NULL && options.num_permitted_cnames != 0 && (direct ||
1127             options.canonicalize_hostname == SSH_CANONICALISE_ALWAYS)) {
1128                 if ((addrs = resolve_host(host, options.port,
1129                     option_clear_or_none(options.proxy_command),
1130                     cname, sizeof(cname))) == NULL) {
1131                         /* Don't fatal proxied host names not in the DNS */
1132                         if (option_clear_or_none(options.proxy_command))
1133                                 cleanup_exit(255); /* logged in resolve_host */
1134                 } else
1135                         check_follow_cname(direct, &host, cname);
1136         }
1137
1138         /*
1139          * If canonicalisation is enabled then re-parse the configuration
1140          * files as new stanzas may match.
1141          */
1142         if (options.canonicalize_hostname != 0) {
1143                 debug("Re-reading configuration after hostname "
1144                     "canonicalisation");
1145                 free(options.hostname);
1146                 options.hostname = xstrdup(host);
1147                 process_config_files(host_arg, pw, 1);
1148                 /*
1149                  * Address resolution happens early with canonicalisation
1150                  * enabled and the port number may have changed since, so
1151                  * reset it in address list
1152                  */
1153                 if (addrs != NULL && options.port > 0)
1154                         set_addrinfo_port(addrs, options.port);
1155         }
1156
1157         /* Fill configuration defaults. */
1158         fill_default_options(&options);
1159
1160         /*
1161          * If ProxyJump option specified, then construct a ProxyCommand now.
1162          */
1163         if (options.jump_host != NULL) {
1164                 char port_s[8];
1165                 const char *sshbin = argv0;
1166
1167                 /*
1168                  * Try to use SSH indicated by argv[0], but fall back to
1169                  * "ssh" if it appears unavailable.
1170                  */
1171                 if (strchr(argv0, '/') != NULL && access(argv0, X_OK) != 0)
1172                         sshbin = "ssh";
1173
1174                 /* Consistency check */
1175                 if (options.proxy_command != NULL)
1176                         fatal("inconsistent options: ProxyCommand+ProxyJump");
1177                 /* Never use FD passing for ProxyJump */
1178                 options.proxy_use_fdpass = 0;
1179                 snprintf(port_s, sizeof(port_s), "%d", options.jump_port);
1180                 xasprintf(&options.proxy_command,
1181                     "%s%s%s%s%s%s%s%s%s%s%.*s -W '[%%h]:%%p' %s",
1182                     sshbin,
1183                     /* Optional "-l user" argument if jump_user set */
1184                     options.jump_user == NULL ? "" : " -l ",
1185                     options.jump_user == NULL ? "" : options.jump_user,
1186                     /* Optional "-p port" argument if jump_port set */
1187                     options.jump_port <= 0 ? "" : " -p ",
1188                     options.jump_port <= 0 ? "" : port_s,
1189                     /* Optional additional jump hosts ",..." */
1190                     options.jump_extra == NULL ? "" : " -J ",
1191                     options.jump_extra == NULL ? "" : options.jump_extra,
1192                     /* Optional "-F" argumment if -F specified */
1193                     config == NULL ? "" : " -F ",
1194                     config == NULL ? "" : config,
1195                     /* Optional "-v" arguments if -v set */
1196                     debug_flag ? " -" : "",
1197                     debug_flag, "vvv",
1198                     /* Mandatory hostname */
1199                     options.jump_host);
1200                 debug("Setting implicit ProxyCommand from ProxyJump: %s",
1201                     options.proxy_command);
1202         }
1203
1204         if (options.port == 0)
1205                 options.port = default_ssh_port();
1206         channel_set_af(ssh, options.address_family);
1207
1208         /* Tidy and check options */
1209         if (options.host_key_alias != NULL)
1210                 lowercase(options.host_key_alias);
1211         if (options.proxy_command != NULL &&
1212             strcmp(options.proxy_command, "-") == 0 &&
1213             options.proxy_use_fdpass)
1214                 fatal("ProxyCommand=- and ProxyUseFDPass are incompatible");
1215         if (options.control_persist &&
1216             options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK) {
1217                 debug("UpdateHostKeys=ask is incompatible with ControlPersist; "
1218                     "disabling");
1219                 options.update_hostkeys = 0;
1220         }
1221         if (options.connection_attempts <= 0)
1222                 fatal("Invalid number of ConnectionAttempts");
1223
1224         if (sshbuf_len(command) != 0 && options.remote_command != NULL)
1225                 fatal("Cannot execute command-line and remote command.");
1226
1227         /* Cannot fork to background if no command. */
1228         if (fork_after_authentication_flag && sshbuf_len(command) == 0 &&
1229             options.remote_command == NULL && !no_shell_flag)
1230                 fatal("Cannot fork into background without a command "
1231                     "to execute.");
1232
1233         /* reinit */
1234         log_init(argv0, options.log_level, options.log_facility, !use_syslog);
1235
1236         if (options.request_tty == REQUEST_TTY_YES ||
1237             options.request_tty == REQUEST_TTY_FORCE)
1238                 tty_flag = 1;
1239
1240         /* Allocate a tty by default if no command specified. */
1241         if (sshbuf_len(command) == 0 && options.remote_command == NULL)
1242                 tty_flag = options.request_tty != REQUEST_TTY_NO;
1243
1244         /* Force no tty */
1245         if (options.request_tty == REQUEST_TTY_NO ||
1246             (muxclient_command && muxclient_command != SSHMUX_COMMAND_PROXY))
1247                 tty_flag = 0;
1248         /* Do not allocate a tty if stdin is not a tty. */
1249         if ((!isatty(fileno(stdin)) || stdin_null_flag) &&
1250             options.request_tty != REQUEST_TTY_FORCE) {
1251                 if (tty_flag)
1252                         logit("Pseudo-terminal will not be allocated because "
1253                             "stdin is not a terminal.");
1254                 tty_flag = 0;
1255         }
1256
1257         seed_rng();
1258
1259         if (options.user == NULL)
1260                 options.user = xstrdup(pw->pw_name);
1261
1262         /* Set up strings used to percent_expand() arguments */
1263         if (gethostname(thishost, sizeof(thishost)) == -1)
1264                 fatal("gethostname: %s", strerror(errno));
1265         strlcpy(shorthost, thishost, sizeof(shorthost));
1266         shorthost[strcspn(thishost, ".")] = '\0';
1267         snprintf(portstr, sizeof(portstr), "%d", options.port);
1268         snprintf(uidstr, sizeof(uidstr), "%llu",
1269             (unsigned long long)pw->pw_uid);
1270
1271         /* Find canonic host name. */
1272         if (strchr(host, '.') == 0) {
1273                 struct addrinfo hints;
1274                 struct addrinfo *ai = NULL;
1275                 int errgai;
1276                 memset(&hints, 0, sizeof(hints));
1277                 hints.ai_family = options.address_family;
1278                 hints.ai_flags = AI_CANONNAME;
1279                 hints.ai_socktype = SOCK_STREAM;
1280                 errgai = getaddrinfo(host, NULL, &hints, &ai);
1281                 if (errgai == 0) {
1282                         if (ai->ai_canonname != NULL)
1283                                 host = xstrdup(ai->ai_canonname);
1284                         freeaddrinfo(ai);
1285                 }
1286         }
1287
1288         if ((md = ssh_digest_start(SSH_DIGEST_SHA1)) == NULL ||
1289             ssh_digest_update(md, thishost, strlen(thishost)) < 0 ||
1290             ssh_digest_update(md, host, strlen(host)) < 0 ||
1291             ssh_digest_update(md, portstr, strlen(portstr)) < 0 ||
1292             ssh_digest_update(md, options.user, strlen(options.user)) < 0 ||
1293             ssh_digest_final(md, conn_hash, sizeof(conn_hash)) < 0)
1294                 fatal("%s: mux digest failed", __func__);
1295         ssh_digest_free(md);
1296         conn_hash_hex = tohex(conn_hash, ssh_digest_bytes(SSH_DIGEST_SHA1));
1297
1298         /*
1299          * Expand tokens in arguments. NB. LocalCommand is expanded later,
1300          * after port-forwarding is set up, so it may pick up any local
1301          * tunnel interface name allocated.
1302          */
1303         if (options.remote_command != NULL) {
1304                 debug3("expanding RemoteCommand: %s", options.remote_command);
1305                 cp = options.remote_command;
1306                 options.remote_command = percent_expand(cp,
1307                     "C", conn_hash_hex,
1308                     "L", shorthost,
1309                     "d", pw->pw_dir,
1310                     "h", host,
1311                     "i", uidstr,
1312                     "l", thishost,
1313                     "n", host_arg,
1314                     "p", portstr,
1315                     "r", options.user,
1316                     "u", pw->pw_name,
1317                     (char *)NULL);
1318                 debug3("expanded RemoteCommand: %s", options.remote_command);
1319                 free(cp);
1320                 if ((r = sshbuf_put(command, options.remote_command,
1321                     strlen(options.remote_command))) != 0)
1322                         fatal("%s: buffer error: %s", __func__, ssh_err(r));
1323         }
1324
1325         if (options.control_path != NULL) {
1326                 cp = tilde_expand_filename(options.control_path, getuid());
1327                 free(options.control_path);
1328                 options.control_path = percent_expand(cp,
1329                     "C", conn_hash_hex,
1330                     "L", shorthost,
1331                     "h", host,
1332                     "i", uidstr,
1333                     "l", thishost,
1334                     "n", host_arg,
1335                     "p", portstr,
1336                     "r", options.user,
1337                     "u", pw->pw_name,
1338                     "i", uidstr,
1339                     (char *)NULL);
1340                 free(cp);
1341         }
1342
1343         if (config_test) {
1344                 dump_client_config(&options, host);
1345                 exit(0);
1346         }
1347
1348         if (muxclient_command != 0 && options.control_path == NULL)
1349                 fatal("No ControlPath specified for \"-O\" command");
1350         if (options.control_path != NULL) {
1351                 int sock;
1352                 if ((sock = muxclient(options.control_path)) >= 0) {
1353                         ssh_packet_set_connection(ssh, sock, sock);
1354                         packet_set_mux();
1355                         goto skip_connect;
1356                 }
1357         }
1358
1359         /*
1360          * If hostname canonicalisation was not enabled, then we may not
1361          * have yet resolved the hostname. Do so now.
1362          */
1363         if (addrs == NULL && options.proxy_command == NULL) {
1364                 debug2("resolving \"%s\" port %d", host, options.port);
1365                 if ((addrs = resolve_host(host, options.port, 1,
1366                     cname, sizeof(cname))) == NULL)
1367                         cleanup_exit(255); /* resolve_host logs the error */
1368         }
1369
1370         timeout_ms = options.connection_timeout * 1000;
1371
1372         /* Open a connection to the remote host. */
1373         if (ssh_connect(ssh, host, addrs, &hostaddr, options.port,
1374             options.address_family, options.connection_attempts,
1375             &timeout_ms, options.tcp_keep_alive) != 0)
1376                 exit(255);
1377
1378         if (addrs != NULL)
1379                 freeaddrinfo(addrs);
1380
1381         packet_set_timeout(options.server_alive_interval,
1382             options.server_alive_count_max);
1383
1384         ssh = active_state; /* XXX */
1385
1386         if (timeout_ms > 0)
1387                 debug3("timeout: %d ms remain after connect", timeout_ms);
1388
1389         /*
1390          * If we successfully made the connection and we have hostbased auth
1391          * enabled, load the public keys so we can later use the ssh-keysign
1392          * helper to sign challenges.
1393          */
1394         sensitive_data.nkeys = 0;
1395         sensitive_data.keys = NULL;
1396         if (options.hostbased_authentication) {
1397                 sensitive_data.nkeys = 10;
1398                 sensitive_data.keys = xcalloc(sensitive_data.nkeys,
1399                     sizeof(struct sshkey));
1400
1401                 /* XXX check errors? */
1402 #define L_PUBKEY(p,o) do { \
1403         if ((o) >= sensitive_data.nkeys) \
1404                 fatal("%s pubkey out of array bounds", __func__); \
1405         check_load(sshkey_load_public(p, &(sensitive_data.keys[o]), NULL), \
1406             p, "pubkey"); \
1407 } while (0)
1408 #define L_CERT(p,o) do { \
1409         if ((o) >= sensitive_data.nkeys) \
1410                 fatal("%s cert out of array bounds", __func__); \
1411         check_load(sshkey_load_cert(p, &(sensitive_data.keys[o])), p, "cert"); \
1412 } while (0)
1413
1414                 if (options.hostbased_authentication == 1) {
1415                         L_CERT(_PATH_HOST_ECDSA_KEY_FILE, 0);
1416                         L_CERT(_PATH_HOST_ED25519_KEY_FILE, 1);
1417                         L_CERT(_PATH_HOST_RSA_KEY_FILE, 2);
1418                         L_CERT(_PATH_HOST_DSA_KEY_FILE, 3);
1419                         L_PUBKEY(_PATH_HOST_ECDSA_KEY_FILE, 4);
1420                         L_PUBKEY(_PATH_HOST_ED25519_KEY_FILE, 5);
1421                         L_PUBKEY(_PATH_HOST_RSA_KEY_FILE, 6);
1422                         L_PUBKEY(_PATH_HOST_DSA_KEY_FILE, 7);
1423                         L_CERT(_PATH_HOST_XMSS_KEY_FILE, 8);
1424                         L_PUBKEY(_PATH_HOST_XMSS_KEY_FILE, 9);
1425                 }
1426         }
1427
1428         /* Create ~/.ssh * directory if it doesn't already exist. */
1429         if (config == NULL) {
1430                 r = snprintf(buf, sizeof buf, "%s%s%s", pw->pw_dir,
1431                     strcmp(pw->pw_dir, "/") ? "/" : "", _PATH_SSH_USER_DIR);
1432                 if (r > 0 && (size_t)r < sizeof(buf) && stat(buf, &st) < 0) {
1433 #ifdef WITH_SELINUX
1434                         ssh_selinux_setfscreatecon(buf);
1435 #endif
1436                         if (mkdir(buf, 0700) < 0)
1437                                 error("Could not create directory '%.200s'.",
1438                                     buf);
1439 #ifdef WITH_SELINUX
1440                         ssh_selinux_setfscreatecon(NULL);
1441 #endif
1442                 }
1443         }
1444         /* load options.identity_files */
1445         load_public_identity_files(pw);
1446
1447         /* optionally set the SSH_AUTHSOCKET_ENV_NAME variable */
1448         if (options.identity_agent &&
1449             strcmp(options.identity_agent, SSH_AUTHSOCKET_ENV_NAME) != 0) {
1450                 if (strcmp(options.identity_agent, "none") == 0) {
1451                         unsetenv(SSH_AUTHSOCKET_ENV_NAME);
1452                 } else {
1453                         p = tilde_expand_filename(options.identity_agent,
1454                             getuid());
1455                         cp = percent_expand(p,
1456                             "d", pw->pw_dir,
1457                             "h", host,
1458                             "i", uidstr,
1459                             "l", thishost,
1460                             "r", options.user,
1461                             "u", pw->pw_name,
1462                             (char *)NULL);
1463                         setenv(SSH_AUTHSOCKET_ENV_NAME, cp, 1);
1464                         free(cp);
1465                         free(p);
1466                 }
1467         }
1468
1469         /* Expand ~ in known host file names. */
1470         tilde_expand_paths(options.system_hostfiles,
1471             options.num_system_hostfiles);
1472         tilde_expand_paths(options.user_hostfiles, options.num_user_hostfiles);
1473
1474         signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */
1475         signal(SIGCHLD, main_sigchld_handler);
1476
1477         /* Log into the remote system.  Never returns if the login fails. */
1478         ssh_login(&sensitive_data, host, (struct sockaddr *)&hostaddr,
1479             options.port, pw, timeout_ms);
1480
1481         if (packet_connection_is_on_socket()) {
1482                 verbose("Authenticated to %s ([%s]:%d).", host,
1483                     ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
1484         } else {
1485                 verbose("Authenticated to %s (via proxy).", host);
1486         }
1487
1488         /* We no longer need the private host keys.  Clear them now. */
1489         if (sensitive_data.nkeys != 0) {
1490                 for (i = 0; i < sensitive_data.nkeys; i++) {
1491                         if (sensitive_data.keys[i] != NULL) {
1492                                 /* Destroys contents safely */
1493                                 debug3("clear hostkey %d", i);
1494                                 sshkey_free(sensitive_data.keys[i]);
1495                                 sensitive_data.keys[i] = NULL;
1496                         }
1497                 }
1498                 free(sensitive_data.keys);
1499         }
1500         for (i = 0; i < options.num_identity_files; i++) {
1501                 free(options.identity_files[i]);
1502                 options.identity_files[i] = NULL;
1503                 if (options.identity_keys[i]) {
1504                         sshkey_free(options.identity_keys[i]);
1505                         options.identity_keys[i] = NULL;
1506                 }
1507         }
1508         for (i = 0; i < options.num_certificate_files; i++) {
1509                 free(options.certificate_files[i]);
1510                 options.certificate_files[i] = NULL;
1511         }
1512
1513  skip_connect:
1514         exit_status = ssh_session2(ssh, pw);
1515         packet_close();
1516
1517         if (options.control_path != NULL && muxserver_sock != -1)
1518                 unlink(options.control_path);
1519
1520         /* Kill ProxyCommand if it is running. */
1521         ssh_kill_proxy_command();
1522
1523         return exit_status;
1524 }
1525
1526 static void
1527 control_persist_detach(void)
1528 {
1529         pid_t pid;
1530         int devnull, keep_stderr;
1531
1532         debug("%s: backgrounding master process", __func__);
1533
1534         /*
1535          * master (current process) into the background, and make the
1536          * foreground process a client of the backgrounded master.
1537          */
1538         switch ((pid = fork())) {
1539         case -1:
1540                 fatal("%s: fork: %s", __func__, strerror(errno));
1541         case 0:
1542                 /* Child: master process continues mainloop */
1543                 break;
1544         default:
1545                 /* Parent: set up mux slave to connect to backgrounded master */
1546                 debug2("%s: background process is %ld", __func__, (long)pid);
1547                 stdin_null_flag = ostdin_null_flag;
1548                 options.request_tty = orequest_tty;
1549                 tty_flag = otty_flag;
1550                 close(muxserver_sock);
1551                 muxserver_sock = -1;
1552                 options.control_master = SSHCTL_MASTER_NO;
1553                 muxclient(options.control_path);
1554                 /* muxclient() doesn't return on success. */
1555                 fatal("Failed to connect to new control master");
1556         }
1557         if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1) {
1558                 error("%s: open(\"/dev/null\"): %s", __func__,
1559                     strerror(errno));
1560         } else {
1561                 keep_stderr = log_is_on_stderr() && debug_flag;
1562                 if (dup2(devnull, STDIN_FILENO) == -1 ||
1563                     dup2(devnull, STDOUT_FILENO) == -1 ||
1564                     (!keep_stderr && dup2(devnull, STDERR_FILENO) == -1))
1565                         error("%s: dup2: %s", __func__, strerror(errno));
1566                 if (devnull > STDERR_FILENO)
1567                         close(devnull);
1568         }
1569         daemon(1, 1);
1570         setproctitle("%s [mux]", options.control_path);
1571 }
1572
1573 /* Do fork() after authentication. Used by "ssh -f" */
1574 static void
1575 fork_postauth(void)
1576 {
1577         if (need_controlpersist_detach)
1578                 control_persist_detach();
1579         debug("forking to background");
1580         fork_after_authentication_flag = 0;
1581         if (daemon(1, 1) < 0)
1582                 fatal("daemon() failed: %.200s", strerror(errno));
1583 }
1584
1585 /* Callback for remote forward global requests */
1586 static void
1587 ssh_confirm_remote_forward(struct ssh *ssh, int type, u_int32_t seq, void *ctxt)
1588 {
1589         struct Forward *rfwd = (struct Forward *)ctxt;
1590
1591         /* XXX verbose() on failure? */
1592         debug("remote forward %s for: listen %s%s%d, connect %s:%d",
1593             type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure",
1594             rfwd->listen_path ? rfwd->listen_path :
1595             rfwd->listen_host ? rfwd->listen_host : "",
1596             (rfwd->listen_path || rfwd->listen_host) ? ":" : "",
1597             rfwd->listen_port, rfwd->connect_path ? rfwd->connect_path :
1598             rfwd->connect_host, rfwd->connect_port);
1599         if (rfwd->listen_path == NULL && rfwd->listen_port == 0) {
1600                 if (type == SSH2_MSG_REQUEST_SUCCESS) {
1601                         rfwd->allocated_port = packet_get_int();
1602                         logit("Allocated port %u for remote forward to %s:%d",
1603                             rfwd->allocated_port,
1604                             rfwd->connect_host, rfwd->connect_port);
1605                         channel_update_permission(ssh,
1606                             rfwd->handle, rfwd->allocated_port);
1607                 } else {
1608                         channel_update_permission(ssh, rfwd->handle, -1);
1609                 }
1610         }
1611
1612         if (type == SSH2_MSG_REQUEST_FAILURE) {
1613                 if (options.exit_on_forward_failure) {
1614                         if (rfwd->listen_path != NULL)
1615                                 fatal("Error: remote port forwarding failed "
1616                                     "for listen path %s", rfwd->listen_path);
1617                         else
1618                                 fatal("Error: remote port forwarding failed "
1619                                     "for listen port %d", rfwd->listen_port);
1620                 } else {
1621                         if (rfwd->listen_path != NULL)
1622                                 logit("Warning: remote port forwarding failed "
1623                                     "for listen path %s", rfwd->listen_path);
1624                         else
1625                                 logit("Warning: remote port forwarding failed "
1626                                     "for listen port %d", rfwd->listen_port);
1627                 }
1628         }
1629         if (++remote_forward_confirms_received == options.num_remote_forwards) {
1630                 debug("All remote forwarding requests processed");
1631                 if (fork_after_authentication_flag)
1632                         fork_postauth();
1633         }
1634 }
1635
1636 static void
1637 client_cleanup_stdio_fwd(struct ssh *ssh, int id, void *arg)
1638 {
1639         debug("stdio forwarding: done");
1640         cleanup_exit(0);
1641 }
1642
1643 static void
1644 ssh_stdio_confirm(struct ssh *ssh, int id, int success, void *arg)
1645 {
1646         if (!success)
1647                 fatal("stdio forwarding failed");
1648 }
1649
1650 static void
1651 ssh_init_stdio_forwarding(struct ssh *ssh)
1652 {
1653         Channel *c;
1654         int in, out;
1655
1656         if (options.stdio_forward_host == NULL)
1657                 return;
1658
1659         debug3("%s: %s:%d", __func__, options.stdio_forward_host,
1660             options.stdio_forward_port);
1661
1662         if ((in = dup(STDIN_FILENO)) < 0 ||
1663             (out = dup(STDOUT_FILENO)) < 0)
1664                 fatal("channel_connect_stdio_fwd: dup() in/out failed");
1665         if ((c = channel_connect_stdio_fwd(ssh, options.stdio_forward_host,
1666             options.stdio_forward_port, in, out)) == NULL)
1667                 fatal("%s: channel_connect_stdio_fwd failed", __func__);
1668         channel_register_cleanup(ssh, c->self, client_cleanup_stdio_fwd, 0);
1669         channel_register_open_confirm(ssh, c->self, ssh_stdio_confirm, NULL);
1670 }
1671
1672 static void
1673 ssh_init_forwarding(struct ssh *ssh, char **ifname)
1674 {
1675         int success = 0;
1676         int i;
1677
1678         /* Initiate local TCP/IP port forwardings. */
1679         for (i = 0; i < options.num_local_forwards; i++) {
1680                 debug("Local connections to %.200s:%d forwarded to remote "
1681                     "address %.200s:%d",
1682                     (options.local_forwards[i].listen_path != NULL) ?
1683                     options.local_forwards[i].listen_path :
1684                     (options.local_forwards[i].listen_host == NULL) ?
1685                     (options.fwd_opts.gateway_ports ? "*" : "LOCALHOST") :
1686                     options.local_forwards[i].listen_host,
1687                     options.local_forwards[i].listen_port,
1688                     (options.local_forwards[i].connect_path != NULL) ?
1689                     options.local_forwards[i].connect_path :
1690                     options.local_forwards[i].connect_host,
1691                     options.local_forwards[i].connect_port);
1692                 success += channel_setup_local_fwd_listener(ssh,
1693                     &options.local_forwards[i], &options.fwd_opts);
1694         }
1695         if (i > 0 && success != i && options.exit_on_forward_failure)
1696                 fatal("Could not request local forwarding.");
1697         if (i > 0 && success == 0)
1698                 error("Could not request local forwarding.");
1699
1700         /* Initiate remote TCP/IP port forwardings. */
1701         for (i = 0; i < options.num_remote_forwards; i++) {
1702                 debug("Remote connections from %.200s:%d forwarded to "
1703                     "local address %.200s:%d",
1704                     (options.remote_forwards[i].listen_path != NULL) ?
1705                     options.remote_forwards[i].listen_path :
1706                     (options.remote_forwards[i].listen_host == NULL) ?
1707                     "LOCALHOST" : options.remote_forwards[i].listen_host,
1708                     options.remote_forwards[i].listen_port,
1709                     (options.remote_forwards[i].connect_path != NULL) ?
1710                     options.remote_forwards[i].connect_path :
1711                     options.remote_forwards[i].connect_host,
1712                     options.remote_forwards[i].connect_port);
1713                 options.remote_forwards[i].handle =
1714                     channel_request_remote_forwarding(ssh,
1715                     &options.remote_forwards[i]);
1716                 if (options.remote_forwards[i].handle < 0) {
1717                         if (options.exit_on_forward_failure)
1718                                 fatal("Could not request remote forwarding.");
1719                         else
1720                                 logit("Warning: Could not request remote "
1721                                     "forwarding.");
1722                 } else {
1723                         client_register_global_confirm(
1724                             ssh_confirm_remote_forward,
1725                             &options.remote_forwards[i]);
1726                 }
1727         }
1728
1729         /* Initiate tunnel forwarding. */
1730         if (options.tun_open != SSH_TUNMODE_NO) {
1731                 if ((*ifname = client_request_tun_fwd(ssh,
1732                     options.tun_open, options.tun_local,
1733                     options.tun_remote)) == NULL) {
1734                         if (options.exit_on_forward_failure)
1735                                 fatal("Could not request tunnel forwarding.");
1736                         else
1737                                 error("Could not request tunnel forwarding.");
1738                 }
1739         }
1740 }
1741
1742 static void
1743 check_agent_present(void)
1744 {
1745         int r;
1746
1747         if (options.forward_agent) {
1748                 /* Clear agent forwarding if we don't have an agent. */
1749                 if ((r = ssh_get_authentication_socket(NULL)) != 0) {
1750                         options.forward_agent = 0;
1751                         if (r != SSH_ERR_AGENT_NOT_PRESENT)
1752                                 debug("ssh_get_authentication_socket: %s",
1753                                     ssh_err(r));
1754                 }
1755         }
1756 }
1757
1758 static void
1759 ssh_session2_setup(struct ssh *ssh, int id, int success, void *arg)
1760 {
1761         extern char **environ;
1762         const char *display;
1763         int interactive = tty_flag;
1764         char *proto = NULL, *data = NULL;
1765
1766         if (!success)
1767                 return; /* No need for error message, channels code sens one */
1768
1769         display = getenv("DISPLAY");
1770         if (display == NULL && options.forward_x11)
1771                 debug("X11 forwarding requested but DISPLAY not set");
1772         if (options.forward_x11 && client_x11_get_proto(ssh, display,
1773             options.xauth_location, options.forward_x11_trusted,
1774             options.forward_x11_timeout, &proto, &data) == 0) {
1775                 /* Request forwarding with authentication spoofing. */
1776                 debug("Requesting X11 forwarding with authentication "
1777                     "spoofing.");
1778                 x11_request_forwarding_with_spoofing(ssh, id, display, proto,
1779                     data, 1);
1780                 client_expect_confirm(ssh, id, "X11 forwarding", CONFIRM_WARN);
1781                 /* XXX exit_on_forward_failure */
1782                 interactive = 1;
1783         }
1784
1785         check_agent_present();
1786         if (options.forward_agent) {
1787                 debug("Requesting authentication agent forwarding.");
1788                 channel_request_start(ssh, id, "auth-agent-req@openssh.com", 0);
1789                 packet_send();
1790         }
1791
1792         /* Tell the packet module whether this is an interactive session. */
1793         packet_set_interactive(interactive,
1794             options.ip_qos_interactive, options.ip_qos_bulk);
1795
1796         client_session2_setup(ssh, id, tty_flag, subsystem_flag, getenv("TERM"),
1797             NULL, fileno(stdin), command, environ);
1798 }
1799
1800 /* open new channel for a session */
1801 static int
1802 ssh_session2_open(struct ssh *ssh)
1803 {
1804         Channel *c;
1805         int window, packetmax, in, out, err;
1806
1807         if (stdin_null_flag) {
1808                 in = open(_PATH_DEVNULL, O_RDONLY);
1809         } else {
1810                 in = dup(STDIN_FILENO);
1811         }
1812         out = dup(STDOUT_FILENO);
1813         err = dup(STDERR_FILENO);
1814
1815         if (in < 0 || out < 0 || err < 0)
1816                 fatal("dup() in/out/err failed");
1817
1818         /* enable nonblocking unless tty */
1819         if (!isatty(in))
1820                 set_nonblock(in);
1821         if (!isatty(out))
1822                 set_nonblock(out);
1823         if (!isatty(err))
1824                 set_nonblock(err);
1825
1826         window = CHAN_SES_WINDOW_DEFAULT;
1827         packetmax = CHAN_SES_PACKET_DEFAULT;
1828         if (tty_flag) {
1829                 window >>= 1;
1830                 packetmax >>= 1;
1831         }
1832         c = channel_new(ssh,
1833             "session", SSH_CHANNEL_OPENING, in, out, err,
1834             window, packetmax, CHAN_EXTENDED_WRITE,
1835             "client-session", /*nonblock*/0);
1836
1837         debug3("%s: channel_new: %d", __func__, c->self);
1838
1839         channel_send_open(ssh, c->self);
1840         if (!no_shell_flag)
1841                 channel_register_open_confirm(ssh, c->self,
1842                     ssh_session2_setup, NULL);
1843
1844         return c->self;
1845 }
1846
1847 static int
1848 ssh_session2(struct ssh *ssh, struct passwd *pw)
1849 {
1850         int devnull, id = -1;
1851         char *cp, *tun_fwd_ifname = NULL;
1852
1853         /* XXX should be pre-session */
1854         if (!options.control_persist)
1855                 ssh_init_stdio_forwarding(ssh);
1856
1857         ssh_init_forwarding(ssh, &tun_fwd_ifname);
1858
1859         if (options.local_command != NULL) {
1860                 debug3("expanding LocalCommand: %s", options.local_command);
1861                 cp = options.local_command;
1862                 options.local_command = percent_expand(cp,
1863                     "C", conn_hash_hex,
1864                     "L", shorthost,
1865                     "d", pw->pw_dir,
1866                     "h", host,
1867                     "i", uidstr,
1868                     "l", thishost,
1869                     "n", host_arg,
1870                     "p", portstr,
1871                     "r", options.user,
1872                     "u", pw->pw_name,
1873                     "T", tun_fwd_ifname == NULL ? "NONE" : tun_fwd_ifname,
1874                     (char *)NULL);
1875                 debug3("expanded LocalCommand: %s", options.local_command);
1876                 free(cp);
1877         }
1878
1879         /* Start listening for multiplex clients */
1880         if (!packet_get_mux())
1881                 muxserver_listen(ssh);
1882
1883         /*
1884          * If we are in control persist mode and have a working mux listen
1885          * socket, then prepare to background ourselves and have a foreground
1886          * client attach as a control slave.
1887          * NB. we must save copies of the flags that we override for
1888          * the backgrounding, since we defer attachment of the slave until
1889          * after the connection is fully established (in particular,
1890          * async rfwd replies have been received for ExitOnForwardFailure).
1891          */
1892         if (options.control_persist && muxserver_sock != -1) {
1893                 ostdin_null_flag = stdin_null_flag;
1894                 ono_shell_flag = no_shell_flag;
1895                 orequest_tty = options.request_tty;
1896                 otty_flag = tty_flag;
1897                 stdin_null_flag = 1;
1898                 no_shell_flag = 1;
1899                 tty_flag = 0;
1900                 if (!fork_after_authentication_flag)
1901                         need_controlpersist_detach = 1;
1902                 fork_after_authentication_flag = 1;
1903         }
1904         /*
1905          * ControlPersist mux listen socket setup failed, attempt the
1906          * stdio forward setup that we skipped earlier.
1907          */
1908         if (options.control_persist && muxserver_sock == -1)
1909                 ssh_init_stdio_forwarding(ssh);
1910
1911         if (!no_shell_flag)
1912                 id = ssh_session2_open(ssh);
1913         else {
1914                 packet_set_interactive(
1915                     options.control_master == SSHCTL_MASTER_NO,
1916                     options.ip_qos_interactive, options.ip_qos_bulk);
1917         }
1918
1919         /* If we don't expect to open a new session, then disallow it */
1920         if (options.control_master == SSHCTL_MASTER_NO &&
1921             (datafellows & SSH_NEW_OPENSSH)) {
1922                 debug("Requesting no-more-sessions@openssh.com");
1923                 packet_start(SSH2_MSG_GLOBAL_REQUEST);
1924                 packet_put_cstring("no-more-sessions@openssh.com");
1925                 packet_put_char(0);
1926                 packet_send();
1927         }
1928
1929         /* Execute a local command */
1930         if (options.local_command != NULL &&
1931             options.permit_local_command)
1932                 ssh_local_cmd(options.local_command);
1933
1934         /*
1935          * stdout is now owned by the session channel; clobber it here
1936          * so future channel closes are propagated to the local fd.
1937          * NB. this can only happen after LocalCommand has completed,
1938          * as it may want to write to stdout.
1939          */
1940         if (!need_controlpersist_detach) {
1941                 if ((devnull = open(_PATH_DEVNULL, O_WRONLY)) == -1)
1942                         error("%s: open %s: %s", __func__,
1943                             _PATH_DEVNULL, strerror(errno));
1944                 if (dup2(devnull, STDOUT_FILENO) < 0)
1945                         fatal("%s: dup2() stdout failed", __func__);
1946                 if (devnull > STDERR_FILENO)
1947                         close(devnull);
1948         }
1949
1950         /*
1951          * If requested and we are not interested in replies to remote
1952          * forwarding requests, then let ssh continue in the background.
1953          */
1954         if (fork_after_authentication_flag) {
1955                 if (options.exit_on_forward_failure &&
1956                     options.num_remote_forwards > 0) {
1957                         debug("deferring postauth fork until remote forward "
1958                             "confirmation received");
1959                 } else
1960                         fork_postauth();
1961         }
1962
1963         return client_loop(ssh, tty_flag, tty_flag ?
1964             options.escape_char : SSH_ESCAPECHAR_NONE, id);
1965 }
1966
1967 /* Loads all IdentityFile and CertificateFile keys */
1968 static void
1969 load_public_identity_files(struct passwd *pw)
1970 {
1971         char *filename, *cp;
1972         struct sshkey *public;
1973         int i;
1974         u_int n_ids, n_certs;
1975         char *identity_files[SSH_MAX_IDENTITY_FILES];
1976         struct sshkey *identity_keys[SSH_MAX_IDENTITY_FILES];
1977         int identity_file_userprovided[SSH_MAX_IDENTITY_FILES];
1978         char *certificate_files[SSH_MAX_CERTIFICATE_FILES];
1979         struct sshkey *certificates[SSH_MAX_CERTIFICATE_FILES];
1980         int certificate_file_userprovided[SSH_MAX_CERTIFICATE_FILES];
1981 #ifdef ENABLE_PKCS11
1982         struct sshkey **keys;
1983         int nkeys;
1984 #endif /* PKCS11 */
1985
1986         n_ids = n_certs = 0;
1987         memset(identity_files, 0, sizeof(identity_files));
1988         memset(identity_keys, 0, sizeof(identity_keys));
1989         memset(identity_file_userprovided, 0,
1990             sizeof(identity_file_userprovided));
1991         memset(certificate_files, 0, sizeof(certificate_files));
1992         memset(certificates, 0, sizeof(certificates));
1993         memset(certificate_file_userprovided, 0,
1994             sizeof(certificate_file_userprovided));
1995
1996 #ifdef ENABLE_PKCS11
1997         if (options.pkcs11_provider != NULL &&
1998             options.num_identity_files < SSH_MAX_IDENTITY_FILES &&
1999             (pkcs11_init(!options.batch_mode) == 0) &&
2000             (nkeys = pkcs11_add_provider(options.pkcs11_provider, NULL,
2001             &keys)) > 0) {
2002                 for (i = 0; i < nkeys; i++) {
2003                         if (n_ids >= SSH_MAX_IDENTITY_FILES) {
2004                                 sshkey_free(keys[i]);
2005                                 continue;
2006                         }
2007                         identity_keys[n_ids] = keys[i];
2008                         identity_files[n_ids] =
2009                             xstrdup(options.pkcs11_provider); /* XXX */
2010                         n_ids++;
2011                 }
2012                 free(keys);
2013         }
2014 #endif /* ENABLE_PKCS11 */
2015         for (i = 0; i < options.num_identity_files; i++) {
2016                 if (n_ids >= SSH_MAX_IDENTITY_FILES ||
2017                     strcasecmp(options.identity_files[i], "none") == 0) {
2018                         free(options.identity_files[i]);
2019                         options.identity_files[i] = NULL;
2020                         continue;
2021                 }
2022                 cp = tilde_expand_filename(options.identity_files[i], getuid());
2023                 filename = percent_expand(cp, "d", pw->pw_dir,
2024                     "u", pw->pw_name, "l", thishost, "h", host,
2025                     "r", options.user, (char *)NULL);
2026                 free(cp);
2027                 check_load(sshkey_load_public(filename, &public, NULL),
2028                     filename, "pubkey");
2029                 debug("identity file %s type %d", filename,
2030                     public ? public->type : -1);
2031                 free(options.identity_files[i]);
2032                 identity_files[n_ids] = filename;
2033                 identity_keys[n_ids] = public;
2034                 identity_file_userprovided[n_ids] =
2035                     options.identity_file_userprovided[i];
2036                 if (++n_ids >= SSH_MAX_IDENTITY_FILES)
2037                         continue;
2038
2039                 /*
2040                  * If no certificates have been explicitly listed then try
2041                  * to add the default certificate variant too.
2042                  */
2043                 if (options.num_certificate_files != 0)
2044                         continue;
2045                 xasprintf(&cp, "%s-cert", filename);
2046                 check_load(sshkey_load_public(cp, &public, NULL),
2047                     filename, "pubkey");
2048                 debug("identity file %s type %d", cp,
2049                     public ? public->type : -1);
2050                 if (public == NULL) {
2051                         free(cp);
2052                         continue;
2053                 }
2054                 if (!sshkey_is_cert(public)) {
2055                         debug("%s: key %s type %s is not a certificate",
2056                             __func__, cp, sshkey_type(public));
2057                         sshkey_free(public);
2058                         free(cp);
2059                         continue;
2060                 }
2061                 /* NB. leave filename pointing to private key */
2062                 identity_files[n_ids] = xstrdup(filename);
2063                 identity_keys[n_ids] = public;
2064                 identity_file_userprovided[n_ids] =
2065                     options.identity_file_userprovided[i];
2066                 n_ids++;
2067         }
2068
2069         if (options.num_certificate_files > SSH_MAX_CERTIFICATE_FILES)
2070                 fatal("%s: too many certificates", __func__);
2071         for (i = 0; i < options.num_certificate_files; i++) {
2072                 cp = tilde_expand_filename(options.certificate_files[i],
2073                     getuid());
2074                 filename = percent_expand(cp,
2075                     "d", pw->pw_dir,
2076                     "h", host,
2077                     "i", uidstr,
2078                     "l", thishost,
2079                     "r", options.user,
2080                     "u", pw->pw_name,
2081                     (char *)NULL);
2082                 free(cp);
2083
2084                 check_load(sshkey_load_public(filename, &public, NULL),
2085                     filename, "certificate");
2086                 debug("certificate file %s type %d", filename,
2087                     public ? public->type : -1);
2088                 free(options.certificate_files[i]);
2089                 options.certificate_files[i] = NULL;
2090                 if (public == NULL) {
2091                         free(filename);
2092                         continue;
2093                 }
2094                 if (!sshkey_is_cert(public)) {
2095                         debug("%s: key %s type %s is not a certificate",
2096                             __func__, filename, sshkey_type(public));
2097                         sshkey_free(public);
2098                         free(filename);
2099                         continue;
2100                 }
2101                 certificate_files[n_certs] = filename;
2102                 certificates[n_certs] = public;
2103                 certificate_file_userprovided[n_certs] =
2104                     options.certificate_file_userprovided[i];
2105                 ++n_certs;
2106         }
2107
2108         options.num_identity_files = n_ids;
2109         memcpy(options.identity_files, identity_files, sizeof(identity_files));
2110         memcpy(options.identity_keys, identity_keys, sizeof(identity_keys));
2111         memcpy(options.identity_file_userprovided,
2112             identity_file_userprovided, sizeof(identity_file_userprovided));
2113
2114         options.num_certificate_files = n_certs;
2115         memcpy(options.certificate_files,
2116             certificate_files, sizeof(certificate_files));
2117         memcpy(options.certificates, certificates, sizeof(certificates));
2118         memcpy(options.certificate_file_userprovided,
2119             certificate_file_userprovided,
2120             sizeof(certificate_file_userprovided));
2121 }
2122
2123 static void
2124 main_sigchld_handler(int sig)
2125 {
2126         int save_errno = errno;
2127         pid_t pid;
2128         int status;
2129
2130         while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
2131             (pid < 0 && errno == EINTR))
2132                 ;
2133         errno = save_errno;
2134 }