crypto/openssh/ssh.c

   1 /* $OpenBSD: ssh.c,v 1.500 2019/01/19 21:43:56 djm Exp $ */
   2 /*
   3  * Author: Tatu Ylonen <ylo@cs.hut.fi>
   4  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
   5  *                    All rights reserved
   6  * Ssh client program.  This program can be used to log into a remote machine.
   7  * The software supports strong authentication, encryption, and forwarding
   8  * of X11, TCP/IP, and authentication connections.
   9  *
  10  * As far as I am concerned, the code I have written for this software
  11  * can be used freely for any purpose.  Any derived versions of this
  12  * software must be clearly marked as such, and if the derived work is
  13  * incompatible with the protocol description in the RFC file, it must be
  14  * called by a name other than "ssh" or "Secure Shell".
  15  *
  16  * Copyright (c) 1999 Niels Provos.  All rights reserved.
  17  * Copyright (c) 2000, 2001, 2002, 2003 Markus Friedl.  All rights reserved.
  18  *
  19  * Modified to work with SSL by Niels Provos <provos@citi.umich.edu>
  20  * in Canada (German citizen).
  21  *
  22  * Redistribution and use in source and binary forms, with or without
  23  * modification, are permitted provided that the following conditions
  24  * are met:
  25  * 1. Redistributions of source code must retain the above copyright
  26  *    notice, this list of conditions and the following disclaimer.
  27  * 2. Redistributions in binary form must reproduce the above copyright
  28  *    notice, this list of conditions and the following disclaimer in the
  29  *    documentation and/or other materials provided with the distribution.
  30  *
  31  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  32  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  33  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  34  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  35  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  36  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  37  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  38  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  39  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  40  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  41  */
  42
  43 #include "includes.h"
  44
  45 #include <sys/types.h>
  46 #ifdef HAVE_SYS_STAT_H
  47 # include <sys/stat.h>
  48 #endif
  49 #include <sys/resource.h>
  50 #include <sys/ioctl.h>
  51 #include <sys/socket.h>
  52 #include <sys/wait.h>
  53
  54 #include <ctype.h>
  55 #include <errno.h>
  56 #include <fcntl.h>
  57 #include <netdb.h>
  58 #ifdef HAVE_PATHS_H
  59 #include <paths.h>
  60 #endif
  61 #include <pwd.h>
  62 #include <signal.h>
  63 #include <stdarg.h>
  64 #include <stddef.h>
  65 #include <stdio.h>
  66 #include <stdlib.h>
  67 #include <string.h>
  68 #include <unistd.h>
  69 #include <limits.h>
  70 #include <locale.h>
  71
  72 #include <netinet/in.h>
  73 #include <arpa/inet.h>
  74
  75 #ifdef WITH_OPENSSL
  76 #include <openssl/evp.h>
  77 #include <openssl/err.h>
  78 #endif
  79 #include "openbsd-compat/openssl-compat.h"
  80 #include "openbsd-compat/sys-queue.h"
  81
  82 #include "xmalloc.h"
  83 #include "ssh.h"
  84 #include "ssh2.h"
  85 #include "canohost.h"
  86 #include "compat.h"
  87 #include "cipher.h"
  88 #include "digest.h"
  89 #include "packet.h"
  90 #include "sshbuf.h"
  91 #include "channels.h"
  92 #include "sshkey.h"
  93 #include "authfd.h"
  94 #include "authfile.h"
  95 #include "pathnames.h"
  96 #include "dispatch.h"
  97 #include "clientloop.h"
  98 #include "log.h"
  99 #include "misc.h"
 100 #include "readconf.h"
 101 #include "sshconnect.h"
 102 #include "kex.h"
 103 #include "mac.h"
 104 #include "sshpty.h"
 105 #include "match.h"
 106 #include "msg.h"
 107 #include "version.h"
 108 #include "ssherr.h"
 109 #include "myproposal.h"
 110 #include "utf8.h"
 111
 112 #ifdef ENABLE_PKCS11
 113 #include "ssh-pkcs11.h"
 114 #endif
 115
 116 extern char *__progname;
 117
 118 /* Saves a copy of argv for setproctitle emulation */
 119 #ifndef HAVE_SETPROCTITLE
 120 static char **saved_av;
 121 #endif
 122
 123 /* Flag indicating whether debug mode is on.  May be set on the command line. */
 124 int debug_flag = 0;
 125
 126 /* Flag indicating whether a tty should be requested */
 127 int tty_flag = 0;
 128
 129 /* don't exec a shell */
 130 int no_shell_flag = 0;
 131
 132 /*
 133  * Flag indicating that nothing should be read from stdin.  This can be set
 134  * on the command line.
 135  */
 136 int stdin_null_flag = 0;
 137
 138 /*
 139  * Flag indicating that the current process should be backgrounded and
 140  * a new slave launched in the foreground for ControlPersist.
 141  */
 142 int need_controlpersist_detach = 0;
 143
 144 /* Copies of flags for ControlPersist foreground slave */
 145 int ostdin_null_flag, ono_shell_flag, otty_flag, orequest_tty;
 146
 147 /*
 148  * Flag indicating that ssh should fork after authentication.  This is useful
 149  * so that the passphrase can be entered manually, and then ssh goes to the
 150  * background.
 151  */
 152 int fork_after_authentication_flag = 0;
 153
 154 /*
 155  * General data structure for command line options and options configurable
 156  * in configuration files.  See readconf.h.
 157  */
 158 Options options;
 159
 160 /* optional user configfile */
 161 char *config = NULL;
 162
 163 /*
 164  * Name of the host we are connecting to.  This is the name given on the
 165  * command line, or the HostName specified for the user-supplied name in a
 166  * configuration file.
 167  */
 168 char *host;
 169
 170 /* Various strings used to to percent_expand() arguments */
 171 static char thishost[NI_MAXHOST], shorthost[NI_MAXHOST], portstr[NI_MAXSERV];
 172 static char uidstr[32], *host_arg, *conn_hash_hex;
 173
 174 /* socket address the host resolves to */
 175 struct sockaddr_storage hostaddr;
 176
 177 /* Private host keys. */
 178 Sensitive sensitive_data;
 179
 180 /* command to be executed */
 181 struct sshbuf *command;
 182
 183 /* Should we execute a command or invoke a subsystem? */
 184 int subsystem_flag = 0;
 185
 186 /* # of replies received for global requests */
 187 static int remote_forward_confirms_received = 0;
 188
 189 /* mux.c */
 190 extern int muxserver_sock;
 191 extern u_int muxclient_command;
 192
 193 /* Prints a help message to the user.  This function never returns. */
 194
 195 static void
 196 usage(void)
 197 {
 198         fprintf(stderr,
 199 "usage: ssh [-46AaCfGgKkMNnqsTtVvXxYy] [-B bind_interface]\n"
 200 "           [-b bind_address] [-c cipher_spec] [-D [bind_address:]port]\n"
 201 "           [-E log_file] [-e escape_char] [-F configfile] [-I pkcs11]\n"
 202 "           [-i identity_file] [-J [user@]host[:port]] [-L address]\n"
 203 "           [-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port]\n"
 204 "           [-Q query_option] [-R address] [-S ctl_path] [-W host:port]\n"
 205 "           [-w local_tun[:remote_tun]] destination [command]\n"
 206         );
 207         exit(255);
 208 }
 209
 210 static int ssh_session2(struct ssh *, struct passwd *);
 211 static void load_public_identity_files(struct passwd *);
 212 static void main_sigchld_handler(int);
 213
 214 /* ~/ expand a list of paths. NB. assumes path[n] is heap-allocated. */
 215 static void
 216 tilde_expand_paths(char **paths, u_int num_paths)
 217 {
 218         u_int i;
 219         char *cp;
 220
 221         for (i = 0; i < num_paths; i++) {
 222                 cp = tilde_expand_filename(paths[i], getuid());
 223                 free(paths[i]);
 224                 paths[i] = cp;
 225         }
 226 }
 227
 228 /*
 229  * Attempt to resolve a host name / port to a set of addresses and
 230  * optionally return any CNAMEs encountered along the way.
 231  * Returns NULL on failure.
 232  * NB. this function must operate with a options having undefined members.
 233  */
 234 static struct addrinfo *
 235 resolve_host(const char *name, int port, int logerr, char *cname, size_t clen)
 236 {
 237         char strport[NI_MAXSERV];
 238         struct addrinfo hints, *res;
 239         int gaierr, loglevel = SYSLOG_LEVEL_DEBUG1;
 240
 241         if (port <= 0)
 242                 port = default_ssh_port();
 243
 244         snprintf(strport, sizeof strport, "%d", port);
 245         memset(&hints, 0, sizeof(hints));
 246         hints.ai_family = options.address_family == -1 ?
 247             AF_UNSPEC : options.address_family;
 248         hints.ai_socktype = SOCK_STREAM;
 249         if (cname != NULL)
 250                 hints.ai_flags = AI_CANONNAME;
 251         if ((gaierr = getaddrinfo(name, strport, &hints, &res)) != 0) {
 252                 if (logerr || (gaierr != EAI_NONAME && gaierr != EAI_NODATA))
 253                         loglevel = SYSLOG_LEVEL_ERROR;
 254                 do_log2(loglevel, "%s: Could not resolve hostname %.100s: %s",
 255                     __progname, name, ssh_gai_strerror(gaierr));
 256                 return NULL;
 257         }
 258         if (cname != NULL && res->ai_canonname != NULL) {
 259                 if (strlcpy(cname, res->ai_canonname, clen) >= clen) {
 260                         error("%s: host \"%s\" cname \"%s\" too long (max %lu)",
 261                             __func__, name,  res->ai_canonname, (u_long)clen);
 262                         if (clen > 0)
 263                                 *cname = '\0';
 264                 }
 265         }
 266         return res;
 267 }
 268
 269 /* Returns non-zero if name can only be an address and not a hostname */
 270 static int
 271 is_addr_fast(const char *name)
 272 {
 273         return (strchr(name, '%') != NULL || strchr(name, ':') != NULL ||
 274             strspn(name, "0123456789.") == strlen(name));
 275 }
 276
 277 /* Returns non-zero if name represents a valid, single address */
 278 static int
 279 is_addr(const char *name)
 280 {
 281         char strport[NI_MAXSERV];
 282         struct addrinfo hints, *res;
 283
 284         if (is_addr_fast(name))
 285                 return 1;
 286
 287         snprintf(strport, sizeof strport, "%u", default_ssh_port());
 288         memset(&hints, 0, sizeof(hints));
 289         hints.ai_family = options.address_family == -1 ?
 290             AF_UNSPEC : options.address_family;
 291         hints.ai_socktype = SOCK_STREAM;
 292         hints.ai_flags = AI_NUMERICHOST|AI_NUMERICSERV;
 293         if (getaddrinfo(name, strport, &hints, &res) != 0)
 294                 return 0;
 295         if (res == NULL || res->ai_next != NULL) {
 296                 freeaddrinfo(res);
 297                 return 0;
 298         }
 299         freeaddrinfo(res);
 300         return 1;
 301 }
 302
 303 /*
 304  * Attempt to resolve a numeric host address / port to a single address.
 305  * Returns a canonical address string.
 306  * Returns NULL on failure.
 307  * NB. this function must operate with a options having undefined members.
 308  */
 309 static struct addrinfo *
 310 resolve_addr(const char *name, int port, char *caddr, size_t clen)
 311 {
 312         char addr[NI_MAXHOST], strport[NI_MAXSERV];
 313         struct addrinfo hints, *res;
 314         int gaierr;
 315
 316         if (port <= 0)
 317                 port = default_ssh_port();
 318         snprintf(strport, sizeof strport, "%u", port);
 319         memset(&hints, 0, sizeof(hints));
 320         hints.ai_family = options.address_family == -1 ?
 321             AF_UNSPEC : options.address_family;
 322         hints.ai_socktype = SOCK_STREAM;
 323         hints.ai_flags = AI_NUMERICHOST|AI_NUMERICSERV;
 324         if ((gaierr = getaddrinfo(name, strport, &hints, &res)) != 0) {
 325                 debug2("%s: could not resolve name %.100s as address: %s",
 326                     __func__, name, ssh_gai_strerror(gaierr));
 327                 return NULL;
 328         }
 329         if (res == NULL) {
 330                 debug("%s: getaddrinfo %.100s returned no addresses",
 331                  __func__, name);
 332                 return NULL;
 333         }
 334         if (res->ai_next != NULL) {
 335                 debug("%s: getaddrinfo %.100s returned multiple addresses",
 336                     __func__, name);
 337                 goto fail;
 338         }
 339         if ((gaierr = getnameinfo(res->ai_addr, res->ai_addrlen,
 340             addr, sizeof(addr), NULL, 0, NI_NUMERICHOST)) != 0) {
 341                 debug("%s: Could not format address for name %.100s: %s",
 342                     __func__, name, ssh_gai_strerror(gaierr));
 343                 goto fail;
 344         }
 345         if (strlcpy(caddr, addr, clen) >= clen) {
 346                 error("%s: host \"%s\" addr \"%s\" too long (max %lu)",
 347                     __func__, name,  addr, (u_long)clen);
 348                 if (clen > 0)
 349                         *caddr = '\0';
 350  fail:
 351                 freeaddrinfo(res);
 352                 return NULL;
 353         }
 354         return res;
 355 }
 356
 357 /*
 358  * Check whether the cname is a permitted replacement for the hostname
 359  * and perform the replacement if it is.
 360  * NB. this function must operate with a options having undefined members.
 361  */
 362 static int
 363 check_follow_cname(int direct, char **namep, const char *cname)
 364 {
 365         int i;
 366         struct allowed_cname *rule;
 367
 368         if (*cname == '\0' || options.num_permitted_cnames == 0 ||
 369             strcmp(*namep, cname) == 0)
 370                 return 0;
 371         if (options.canonicalize_hostname == SSH_CANONICALISE_NO)
 372                 return 0;
 373         /*
 374          * Don't attempt to canonicalize names that will be interpreted by
 375          * a proxy or jump host unless the user specifically requests so.
 376          */
 377         if (!direct &&
 378             options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS)
 379                 return 0;
 380         debug3("%s: check \"%s\" CNAME \"%s\"", __func__, *namep, cname);
 381         for (i = 0; i < options.num_permitted_cnames; i++) {
 382                 rule = options.permitted_cnames + i;
 383                 if (match_pattern_list(*namep, rule->source_list, 1) != 1 ||
 384                     match_pattern_list(cname, rule->target_list, 1) != 1)
 385                         continue;
 386                 verbose("Canonicalized DNS aliased hostname "
 387                     "\"%s\" => \"%s\"", *namep, cname);
 388                 free(*namep);
 389                 *namep = xstrdup(cname);
 390                 return 1;
 391         }
 392         return 0;
 393 }
 394
 395 /*
 396  * Attempt to resolve the supplied hostname after applying the user's
 397  * canonicalization rules. Returns the address list for the host or NULL
 398  * if no name was found after canonicalization.
 399  * NB. this function must operate with a options having undefined members.
 400  */
 401 static struct addrinfo *
 402 resolve_canonicalize(char **hostp, int port)
 403 {
 404         int i, direct, ndots;
 405         char *cp, *fullhost, newname[NI_MAXHOST];
 406         struct addrinfo *addrs;
 407
 408         /*
 409          * Attempt to canonicalise addresses, regardless of
 410          * whether hostname canonicalisation was requested
 411          */
 412         if ((addrs = resolve_addr(*hostp, port,
 413             newname, sizeof(newname))) != NULL) {
 414                 debug2("%s: hostname %.100s is address", __func__, *hostp);
 415                 if (strcasecmp(*hostp, newname) != 0) {
 416                         debug2("%s: canonicalised address \"%s\" => \"%s\"",
 417                             __func__, *hostp, newname);
 418                         free(*hostp);
 419                         *hostp = xstrdup(newname);
 420                 }
 421                 return addrs;
 422         }
 423
 424         /*
 425          * If this looks like an address but didn't parse as one, it might
 426          * be an address with an invalid interface scope. Skip further
 427          * attempts at canonicalisation.
 428          */
 429         if (is_addr_fast(*hostp)) {
 430                 debug("%s: hostname %.100s is an unrecognised address",
 431                     __func__, *hostp);
 432                 return NULL;
 433         }
 434
 435         if (options.canonicalize_hostname == SSH_CANONICALISE_NO)
 436                 return NULL;
 437
 438         /*
 439          * Don't attempt to canonicalize names that will be interpreted by
 440          * a proxy unless the user specifically requests so.
 441          */
 442         direct = option_clear_or_none(options.proxy_command) &&
 443             options.jump_host == NULL;
 444         if (!direct &&
 445             options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS)
 446                 return NULL;
 447
 448         /* If domain name is anchored, then resolve it now */
 449         if ((*hostp)[strlen(*hostp) - 1] == '.') {
 450                 debug3("%s: name is fully qualified", __func__);
 451                 fullhost = xstrdup(*hostp);
 452                 if ((addrs = resolve_host(fullhost, port, 0,
 453                     newname, sizeof(newname))) != NULL)
 454                         goto found;
 455                 free(fullhost);
 456                 goto notfound;
 457         }
 458
 459         /* Don't apply canonicalization to sufficiently-qualified hostnames */
 460         ndots = 0;
 461         for (cp = *hostp; *cp != '\0'; cp++) {
 462                 if (*cp == '.')
 463                         ndots++;
 464         }
 465         if (ndots > options.canonicalize_max_dots) {
 466                 debug3("%s: not canonicalizing hostname \"%s\" (max dots %d)",
 467                     __func__, *hostp, options.canonicalize_max_dots);
 468                 return NULL;
 469         }
 470         /* Attempt each supplied suffix */
 471         for (i = 0; i < options.num_canonical_domains; i++) {
 472                 *newname = '\0';
 473                 xasprintf(&fullhost, "%s.%s.", *hostp,
 474                     options.canonical_domains[i]);
 475                 debug3("%s: attempting \"%s\" => \"%s\"", __func__,
 476                     *hostp, fullhost);
 477                 if ((addrs = resolve_host(fullhost, port, 0,
 478                     newname, sizeof(newname))) == NULL) {
 479                         free(fullhost);
 480                         continue;
 481                 }
 482  found:
 483                 /* Remove trailing '.' */
 484                 fullhost[strlen(fullhost) - 1] = '\0';
 485                 /* Follow CNAME if requested */
 486                 if (!check_follow_cname(direct, &fullhost, newname)) {
 487                         debug("Canonicalized hostname \"%s\" => \"%s\"",
 488                             *hostp, fullhost);
 489                 }
 490                 free(*hostp);
 491                 *hostp = fullhost;
 492                 return addrs;
 493         }
 494  notfound:
 495         if (!options.canonicalize_fallback_local)
 496                 fatal("%s: Could not resolve host \"%s\"", __progname, *hostp);
 497         debug2("%s: host %s not found in any suffix", __func__, *hostp);
 498         return NULL;
 499 }
 500
 501 /*
 502  * Check the result of hostkey loading, ignoring some errors and
 503  * fatal()ing for others.
 504  */
 505 static void
 506 check_load(int r, const char *path, const char *message)
 507 {
 508         switch (r) {
 509         case 0:
 510                 break;
 511         case SSH_ERR_INTERNAL_ERROR:
 512         case SSH_ERR_ALLOC_FAIL:
 513                 fatal("load %s \"%s\": %s", message, path, ssh_err(r));
 514         case SSH_ERR_SYSTEM_ERROR:
 515                 /* Ignore missing files */
 516                 if (errno == ENOENT)
 517                         break;
 518                 /* FALLTHROUGH */
 519         default:
 520                 error("load %s \"%s\": %s", message, path, ssh_err(r));
 521                 break;
 522         }
 523 }
 524
 525 /*
 526  * Read per-user configuration file.  Ignore the system wide config
 527  * file if the user specifies a config file on the command line.
 528  */
 529 static void
 530 process_config_files(const char *host_name, struct passwd *pw, int final_pass,
 531     int *want_final_pass)
 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 | (final_pass ? SSHCONF_FINAL : 0),
 540                     want_final_pass))
 541                         fatal("Can't open user config file %.100s: "
 542                             "%.100s", config, strerror(errno));
 543         } else {
 544                 r = snprintf(buf, sizeof buf, "%s/%s", pw->pw_dir,
 545                     _PATH_SSH_USER_CONFFILE);
 546                 if (r > 0 && (size_t)r < sizeof(buf))
 547                         (void)read_config_file(buf, pw, host, host_name,
 548                             &options, SSHCONF_CHECKPERM | SSHCONF_USERCONF |
 549                             (final_pass ? SSHCONF_FINAL : 0), want_final_pass);
 550
 551                 /* Read systemwide configuration file after user config. */
 552                 (void)read_config_file(_PATH_HOST_CONFIG_FILE, pw,
 553                     host, host_name, &options,
 554                     final_pass ? SSHCONF_FINAL : 0, want_final_pass);
 555         }
 556 }
 557
 558 /* Rewrite the port number in an addrinfo list of addresses */
 559 static void
 560 set_addrinfo_port(struct addrinfo *addrs, int port)
 561 {
 562         struct addrinfo *addr;
 563
 564         for (addr = addrs; addr != NULL; addr = addr->ai_next) {
 565                 switch (addr->ai_family) {
 566                 case AF_INET:
 567                         ((struct sockaddr_in *)addr->ai_addr)->
 568                             sin_port = htons(port);
 569                         break;
 570                 case AF_INET6:
 571                         ((struct sockaddr_in6 *)addr->ai_addr)->
 572                             sin6_port = htons(port);
 573                         break;
 574                 }
 575         }
 576 }
 577
 578 /*
 579  * Main program for the ssh client.
 580  */
 581 int
 582 main(int ac, char **av)
 583 {
 584         struct ssh *ssh = NULL;
 585         int i, r, opt, exit_status, use_syslog, direct, timeout_ms;
 586         int was_addr, config_test = 0, opt_terminated = 0, want_final_pass = 0;
 587         char *p, *cp, *line, *argv0, buf[PATH_MAX], *logfile;
 588         char cname[NI_MAXHOST];
 589         struct stat st;
 590         struct passwd *pw;
 591         extern int optind, optreset;
 592         extern char *optarg;
 593         struct Forward fwd;
 594         struct addrinfo *addrs = NULL;
 595         struct ssh_digest_ctx *md;
 596         u_char conn_hash[SSH_DIGEST_MAX_LENGTH];
 597
 598         ssh_malloc_init();      /* must be called before any mallocs */
 599         /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
 600         sanitise_stdfd();
 601
 602         __progname = ssh_get_progname(av[0]);
 603
 604 #ifndef HAVE_SETPROCTITLE
 605         /* Prepare for later setproctitle emulation */
 606         /* Save argv so it isn't clobbered by setproctitle() emulation */
 607         saved_av = xcalloc(ac + 1, sizeof(*saved_av));
 608         for (i = 0; i < ac; i++)
 609                 saved_av[i] = xstrdup(av[i]);
 610         saved_av[i] = NULL;
 611         compat_init_setproctitle(ac, av);
 612         av = saved_av;
 613 #endif
 614
 615         seed_rng();
 616
 617         /*
 618          * Discard other fds that are hanging around. These can cause problem
 619          * with backgrounded ssh processes started by ControlPersist.
 620          */
 621         closefrom(STDERR_FILENO + 1);
 622
 623         /* Get user data. */
 624         pw = getpwuid(getuid());
 625         if (!pw) {
 626                 logit("No user exists for uid %lu", (u_long)getuid());
 627                 exit(255);
 628         }
 629         /* Take a copy of the returned structure. */
 630         pw = pwcopy(pw);
 631
 632         /*
 633          * Set our umask to something reasonable, as some files are created
 634          * with the default umask.  This will make them world-readable but
 635          * writable only by the owner, which is ok for all files for which we
 636          * don't set the modes explicitly.
 637          */
 638         umask(022);
 639
 640         msetlocale();
 641
 642         /*
 643          * Initialize option structure to indicate that no values have been
 644          * set.
 645          */
 646         initialize_options(&options);
 647
 648         /*
 649          * Prepare main ssh transport/connection structures
 650          */
 651         if ((ssh = ssh_alloc_session_state()) == NULL)
 652                 fatal("Couldn't allocate session state");
 653         channel_init_channels(ssh);
 654
 655         /* Parse command-line arguments. */
 656         host = NULL;
 657         use_syslog = 0;
 658         logfile = NULL;
 659         argv0 = av[0];
 660
 661  again:
 662         while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx"
 663             "AB:CD:E:F:GI:J:KL:MNO:PQ:R:S:TVw:W:XYy")) != -1) {
 664                 switch (opt) {
 665                 case '1':
 666                         fatal("SSH protocol v.1 is no longer supported");
 667                         break;
 668                 case '2':
 669                         /* Ignored */
 670                         break;
 671                 case '4':
 672                         options.address_family = AF_INET;
 673                         break;
 674                 case '6':
 675                         options.address_family = AF_INET6;
 676                         break;
 677                 case 'n':
 678                         stdin_null_flag = 1;
 679                         break;
 680                 case 'f':
 681                         fork_after_authentication_flag = 1;
 682                         stdin_null_flag = 1;
 683                         break;
 684                 case 'x':
 685                         options.forward_x11 = 0;
 686                         break;
 687                 case 'X':
 688                         options.forward_x11 = 1;
 689                         break;
 690                 case 'y':
 691                         use_syslog = 1;
 692                         break;
 693                 case 'E':
 694                         logfile = optarg;
 695                         break;
 696                 case 'G':
 697                         config_test = 1;
 698                         break;
 699                 case 'Y':
 700                         options.forward_x11 = 1;
 701                         options.forward_x11_trusted = 1;
 702                         break;
 703                 case 'g':
 704                         options.fwd_opts.gateway_ports = 1;
 705                         break;
 706                 case 'O':
 707                         if (options.stdio_forward_host != NULL)
 708                                 fatal("Cannot specify multiplexing "
 709                                     "command with -W");
 710                         else if (muxclient_command != 0)
 711                                 fatal("Multiplexing command already specified");
 712                         if (strcmp(optarg, "check") == 0)
 713                                 muxclient_command = SSHMUX_COMMAND_ALIVE_CHECK;
 714                         else if (strcmp(optarg, "forward") == 0)
 715                                 muxclient_command = SSHMUX_COMMAND_FORWARD;
 716                         else if (strcmp(optarg, "exit") == 0)
 717                                 muxclient_command = SSHMUX_COMMAND_TERMINATE;
 718                         else if (strcmp(optarg, "stop") == 0)
 719                                 muxclient_command = SSHMUX_COMMAND_STOP;
 720                         else if (strcmp(optarg, "cancel") == 0)
 721                                 muxclient_command = SSHMUX_COMMAND_CANCEL_FWD;
 722                         else if (strcmp(optarg, "proxy") == 0)
 723                                 muxclient_command = SSHMUX_COMMAND_PROXY;
 724                         else
 725                                 fatal("Invalid multiplex command.");
 726                         break;
 727                 case 'P':       /* deprecated */
 728                         break;
 729                 case 'Q':
 730                         cp = NULL;
 731                         if (strcmp(optarg, "cipher") == 0)
 732                                 cp = cipher_alg_list('\n', 0);
 733                         else if (strcmp(optarg, "cipher-auth") == 0)
 734                                 cp = cipher_alg_list('\n', 1);
 735                         else if (strcmp(optarg, "mac") == 0)
 736                                 cp = mac_alg_list('\n');
 737                         else if (strcmp(optarg, "kex") == 0)
 738                                 cp = kex_alg_list('\n');
 739                         else if (strcmp(optarg, "key") == 0)
 740                                 cp = sshkey_alg_list(0, 0, 0, '\n');
 741                         else if (strcmp(optarg, "key-cert") == 0)
 742                                 cp = sshkey_alg_list(1, 0, 0, '\n');
 743                         else if (strcmp(optarg, "key-plain") == 0)
 744                                 cp = sshkey_alg_list(0, 1, 0, '\n');
 745                         else if (strcmp(optarg, "sig") == 0)
 746                                 cp = sshkey_alg_list(0, 1, 1, '\n');
 747                         else if (strcmp(optarg, "protocol-version") == 0)
 748                                 cp = xstrdup("2");
 749                         else if (strcmp(optarg, "help") == 0) {
 750                                 cp = xstrdup(
 751                                     "cipher\ncipher-auth\nkex\nkey\n"
 752                                     "key-cert\nkey-plain\nmac\n"
 753                                     "protocol-version\nsig");
 754                         }
 755                         if (cp == NULL)
 756                                 fatal("Unsupported query \"%s\"", optarg);
 757                         printf("%s\n", cp);
 758                         free(cp);
 759                         exit(0);
 760                         break;
 761                 case 'a':
 762                         options.forward_agent = 0;
 763                         break;
 764                 case 'A':
 765                         options.forward_agent = 1;
 766                         break;
 767                 case 'k':
 768                         options.gss_deleg_creds = 0;
 769                         break;
 770                 case 'K':
 771                         options.gss_authentication = 1;
 772                         options.gss_deleg_creds = 1;
 773                         break;
 774                 case 'i':
 775                         p = tilde_expand_filename(optarg, getuid());
 776                         if (stat(p, &st) < 0)
 777                                 fprintf(stderr, "Warning: Identity file %s "
 778                                     "not accessible: %s.\n", p,
 779                                     strerror(errno));
 780                         else
 781                                 add_identity_file(&options, NULL, p, 1);
 782                         free(p);
 783                         break;
 784                 case 'I':
 785 #ifdef ENABLE_PKCS11
 786                         free(options.pkcs11_provider);
 787                         options.pkcs11_provider = xstrdup(optarg);
 788 #else
 789                         fprintf(stderr, "no support for PKCS#11.\n");
 790 #endif
 791                         break;
 792                 case 'J':
 793                         if (options.jump_host != NULL)
 794                                 fatal("Only a single -J option permitted");
 795                         if (options.proxy_command != NULL)
 796                                 fatal("Cannot specify -J with ProxyCommand");
 797                         if (parse_jump(optarg, &options, 1) == -1)
 798                                 fatal("Invalid -J argument");
 799                         options.proxy_command = xstrdup("none");
 800                         break;
 801                 case 't':
 802                         if (options.request_tty == REQUEST_TTY_YES)
 803                                 options.request_tty = REQUEST_TTY_FORCE;
 804                         else
 805                                 options.request_tty = REQUEST_TTY_YES;
 806                         break;
 807                 case 'v':
 808                         if (debug_flag == 0) {
 809                                 debug_flag = 1;
 810                                 options.log_level = SYSLOG_LEVEL_DEBUG1;
 811                         } else {
 812                                 if (options.log_level < SYSLOG_LEVEL_DEBUG3) {
 813                                         debug_flag++;
 814                                         options.log_level++;
 815                                 }
 816                         }
 817                         break;
 818                 case 'V':
 819                         fprintf(stderr, "%s, %s\n",
 820                             SSH_RELEASE,
 821 #ifdef WITH_OPENSSL
 822                             OpenSSL_version(OPENSSL_VERSION)
 823 #else
 824                             "without OpenSSL"
 825 #endif
 826                         );
 827                         if (opt == 'V')
 828                                 exit(0);
 829                         break;
 830                 case 'w':
 831                         if (options.tun_open == -1)
 832                                 options.tun_open = SSH_TUNMODE_DEFAULT;
 833                         options.tun_local = a2tun(optarg, &options.tun_remote);
 834                         if (options.tun_local == SSH_TUNID_ERR) {
 835                                 fprintf(stderr,
 836                                     "Bad tun device '%s'\n", optarg);
 837                                 exit(255);
 838                         }
 839                         break;
 840                 case 'W':
 841                         if (options.stdio_forward_host != NULL)
 842                                 fatal("stdio forward already specified");
 843                         if (muxclient_command != 0)
 844                                 fatal("Cannot specify stdio forward with -O");
 845                         if (parse_forward(&fwd, optarg, 1, 0)) {
 846                                 options.stdio_forward_host = fwd.listen_host;
 847                                 options.stdio_forward_port = fwd.listen_port;
 848                                 free(fwd.connect_host);
 849                         } else {
 850                                 fprintf(stderr,
 851                                     "Bad stdio forwarding specification '%s'\n",
 852                                     optarg);
 853                                 exit(255);
 854                         }
 855                         options.request_tty = REQUEST_TTY_NO;
 856                         no_shell_flag = 1;
 857                         break;
 858                 case 'q':
 859                         options.log_level = SYSLOG_LEVEL_QUIET;
 860                         break;
 861                 case 'e':
 862                         if (optarg[0] == '^' && optarg[2] == 0 &&
 863                             (u_char) optarg[1] >= 64 &&
 864                             (u_char) optarg[1] < 128)
 865                                 options.escape_char = (u_char) optarg[1] & 31;
 866                         else if (strlen(optarg) == 1)
 867                                 options.escape_char = (u_char) optarg[0];
 868                         else if (strcmp(optarg, "none") == 0)
 869                                 options.escape_char = SSH_ESCAPECHAR_NONE;
 870                         else {
 871                                 fprintf(stderr, "Bad escape character '%s'.\n",
 872                                     optarg);
 873                                 exit(255);
 874                         }
 875                         break;
 876                 case 'c':
 877                         if (!ciphers_valid(*optarg == '+' ?
 878                             optarg + 1 : optarg)) {
 879                                 fprintf(stderr, "Unknown cipher type '%s'\n",
 880                                     optarg);
 881                                 exit(255);
 882                         }
 883                         free(options.ciphers);
 884                         options.ciphers = xstrdup(optarg);
 885                         break;
 886                 case 'm':
 887                         if (mac_valid(optarg)) {
 888                                 free(options.macs);
 889                                 options.macs = xstrdup(optarg);
 890                         } else {
 891                                 fprintf(stderr, "Unknown mac type '%s'\n",
 892                                     optarg);
 893                                 exit(255);
 894                         }
 895                         break;
 896                 case 'M':
 897                         if (options.control_master == SSHCTL_MASTER_YES)
 898                                 options.control_master = SSHCTL_MASTER_ASK;
 899                         else
 900                                 options.control_master = SSHCTL_MASTER_YES;
 901                         break;
 902                 case 'p':
 903                         if (options.port == -1) {
 904                                 options.port = a2port(optarg);
 905                                 if (options.port <= 0) {
 906                                         fprintf(stderr, "Bad port '%s'\n",
 907                                             optarg);
 908                                         exit(255);
 909                                 }
 910                         }
 911                         break;
 912                 case 'l':
 913                         if (options.user == NULL)
 914                                 options.user = optarg;
 915                         break;
 916
 917                 case 'L':
 918                         if (parse_forward(&fwd, optarg, 0, 0))
 919                                 add_local_forward(&options, &fwd);
 920                         else {
 921                                 fprintf(stderr,
 922                                     "Bad local forwarding specification '%s'\n",
 923                                     optarg);
 924                                 exit(255);
 925                         }
 926                         break;
 927
 928                 case 'R':
 929                         if (parse_forward(&fwd, optarg, 0, 1) ||
 930                             parse_forward(&fwd, optarg, 1, 1)) {
 931                                 add_remote_forward(&options, &fwd);
 932                         } else {
 933                                 fprintf(stderr,
 934                                     "Bad remote forwarding specification "
 935                                     "'%s'\n", optarg);
 936                                 exit(255);
 937                         }
 938                         break;
 939
 940                 case 'D':
 941                         if (parse_forward(&fwd, optarg, 1, 0)) {
 942                                 add_local_forward(&options, &fwd);
 943                         } else {
 944                                 fprintf(stderr,
 945                                     "Bad dynamic forwarding specification "
 946                                     "'%s'\n", optarg);
 947                                 exit(255);
 948                         }
 949                         break;
 950
 951                 case 'C':
 952                         options.compression = 1;
 953                         break;
 954                 case 'N':
 955                         no_shell_flag = 1;
 956                         options.request_tty = REQUEST_TTY_NO;
 957                         break;
 958                 case 'T':
 959                         options.request_tty = REQUEST_TTY_NO;
 960                         break;
 961                 case 'o':
 962                         line = xstrdup(optarg);
 963                         if (process_config_line(&options, pw,
 964                             host ? host : "", host ? host : "", line,
 965                             "command-line", 0, NULL, SSHCONF_USERCONF) != 0)
 966                                 exit(255);
 967                         free(line);
 968                         break;
 969                 case 's':
 970                         subsystem_flag = 1;
 971                         break;
 972                 case 'S':
 973                         free(options.control_path);
 974                         options.control_path = xstrdup(optarg);
 975                         break;
 976                 case 'b':
 977                         options.bind_address = optarg;
 978                         break;
 979                 case 'B':
 980                         options.bind_interface = optarg;
 981                         break;
 982                 case 'F':
 983                         config = optarg;
 984                         break;
 985                 default:
 986                         usage();
 987                 }
 988         }
 989
 990         if (optind > 1 && strcmp(av[optind - 1], "--") == 0)
 991                 opt_terminated = 1;
 992
 993         ac -= optind;
 994         av += optind;
 995
 996         if (ac > 0 && !host) {
 997                 int tport;
 998                 char *tuser;
 999                 switch (parse_ssh_uri(*av, &tuser, &host, &tport)) {
1000                 case -1:
1001                         usage();
1002                         break;
1003                 case 0:
1004                         if (options.user == NULL) {
1005                                 options.user = tuser;
1006                                 tuser = NULL;
1007                         }
1008                         free(tuser);
1009                         if (options.port == -1 && tport != -1)
1010                                 options.port = tport;
1011                         break;
1012                 default:
1013                         p = xstrdup(*av);
1014                         cp = strrchr(p, '@');
1015                         if (cp != NULL) {
1016                                 if (cp == p)
1017                                         usage();
1018                                 if (options.user == NULL) {
1019                                         options.user = p;
1020                                         p = NULL;
1021                                 }
1022                                 *cp++ = '\0';
1023                                 host = xstrdup(cp);
1024                                 free(p);
1025                         } else
1026                                 host = p;
1027                         break;
1028                 }
1029                 if (ac > 1 && !opt_terminated) {
1030                         optind = optreset = 1;
1031                         goto again;
1032                 }
1033                 ac--, av++;
1034         }
1035
1036         /* Check that we got a host name. */
1037         if (!host)
1038                 usage();
1039
1040         host_arg = xstrdup(host);
1041
1042         /* Initialize the command to execute on remote host. */
1043         if ((command = sshbuf_new()) == NULL)
1044                 fatal("sshbuf_new failed");
1045
1046         /*
1047          * Save the command to execute on the remote host in a buffer. There
1048          * is no limit on the length of the command, except by the maximum
1049          * packet size.  Also sets the tty flag if there is no command.
1050          */
1051         if (!ac) {
1052                 /* No command specified - execute shell on a tty. */
1053                 if (subsystem_flag) {
1054                         fprintf(stderr,
1055                             "You must specify a subsystem to invoke.\n");
1056                         usage();
1057                 }
1058         } else {
1059                 /* A command has been specified.  Store it into the buffer. */
1060                 for (i = 0; i < ac; i++) {
1061                         if ((r = sshbuf_putf(command, "%s%s",
1062                             i ? " " : "", av[i])) != 0)
1063                                 fatal("%s: buffer error: %s",
1064                                     __func__, ssh_err(r));
1065                 }
1066         }
1067
1068         /*
1069          * Initialize "log" output.  Since we are the client all output
1070          * goes to stderr unless otherwise specified by -y or -E.
1071          */
1072         if (use_syslog && logfile != NULL)
1073                 fatal("Can't specify both -y and -E");
1074         if (logfile != NULL)
1075                 log_redirect_stderr_to(logfile);
1076         log_init(argv0,
1077             options.log_level == SYSLOG_LEVEL_NOT_SET ?
1078             SYSLOG_LEVEL_INFO : options.log_level,
1079             options.log_facility == SYSLOG_FACILITY_NOT_SET ?
1080             SYSLOG_FACILITY_USER : options.log_facility,
1081             !use_syslog);
1082
1083         if (debug_flag)
1084                 logit("%s, %s", SSH_RELEASE,
1085 #ifdef WITH_OPENSSL
1086                     OpenSSL_version(OPENSSL_VERSION)
1087 #else
1088                     "without OpenSSL"
1089 #endif
1090                 );
1091
1092         /* Parse the configuration files */
1093         process_config_files(host_arg, pw, 0, &want_final_pass);
1094         if (want_final_pass)
1095                 debug("configuration requests final Match pass");
1096
1097         /* Hostname canonicalisation needs a few options filled. */
1098         fill_default_options_for_canonicalization(&options);
1099
1100         /* If the user has replaced the hostname then take it into use now */
1101         if (options.hostname != NULL) {
1102                 /* NB. Please keep in sync with readconf.c:match_cfg_line() */
1103                 cp = percent_expand(options.hostname,
1104                     "h", host, (char *)NULL);
1105                 free(host);
1106                 host = cp;
1107                 free(options.hostname);
1108                 options.hostname = xstrdup(host);
1109         }
1110
1111         /* Don't lowercase addresses, they will be explicitly canonicalised */
1112         if ((was_addr = is_addr(host)) == 0)
1113                 lowercase(host);
1114
1115         /*
1116          * Try to canonicalize if requested by configuration or the
1117          * hostname is an address.
1118          */
1119         if (options.canonicalize_hostname != SSH_CANONICALISE_NO || was_addr)
1120                 addrs = resolve_canonicalize(&host, options.port);
1121
1122         /*
1123          * If CanonicalizePermittedCNAMEs have been specified but
1124          * other canonicalization did not happen (by not being requested
1125          * or by failing with fallback) then the hostname may still be changed
1126          * as a result of CNAME following.
1127          *
1128          * Try to resolve the bare hostname name using the system resolver's
1129          * usual search rules and then apply the CNAME follow rules.
1130          *
1131          * Skip the lookup if a ProxyCommand is being used unless the user
1132          * has specifically requested canonicalisation for this case via
1133          * CanonicalizeHostname=always
1134          */
1135         direct = option_clear_or_none(options.proxy_command) &&
1136             options.jump_host == NULL;
1137         if (addrs == NULL && options.num_permitted_cnames != 0 && (direct ||
1138             options.canonicalize_hostname == SSH_CANONICALISE_ALWAYS)) {
1139                 if ((addrs = resolve_host(host, options.port,
1140                     direct, cname, sizeof(cname))) == NULL) {
1141                         /* Don't fatal proxied host names not in the DNS */
1142                         if (direct)
1143                                 cleanup_exit(255); /* logged in resolve_host */
1144                 } else
1145                         check_follow_cname(direct, &host, cname);
1146         }
1147
1148         /*
1149          * If canonicalisation is enabled then re-parse the configuration
1150          * files as new stanzas may match.
1151          */
1152         if (options.canonicalize_hostname != 0 && !want_final_pass) {
1153                 debug("hostname canonicalisation enabled, "
1154                     "will re-parse configuration");
1155                 want_final_pass = 1;
1156         }
1157
1158         if (want_final_pass) {
1159                 debug("re-parsing configuration");
1160                 free(options.hostname);
1161                 options.hostname = xstrdup(host);
1162                 process_config_files(host_arg, pw, 1, NULL);
1163                 /*
1164                  * Address resolution happens early with canonicalisation
1165                  * enabled and the port number may have changed since, so
1166                  * reset it in address list
1167                  */
1168                 if (addrs != NULL && options.port > 0)
1169                         set_addrinfo_port(addrs, options.port);
1170         }
1171
1172         /* Fill configuration defaults. */
1173         fill_default_options(&options);
1174
1175         /*
1176          * If ProxyJump option specified, then construct a ProxyCommand now.
1177          */
1178         if (options.jump_host != NULL) {
1179                 char port_s[8];
1180                 const char *sshbin = argv0;
1181
1182                 /*
1183                  * Try to use SSH indicated by argv[0], but fall back to
1184                  * "ssh" if it appears unavailable.
1185                  */
1186                 if (strchr(argv0, '/') != NULL && access(argv0, X_OK) != 0)
1187                         sshbin = "ssh";
1188
1189                 /* Consistency check */
1190                 if (options.proxy_command != NULL)
1191                         fatal("inconsistent options: ProxyCommand+ProxyJump");
1192                 /* Never use FD passing for ProxyJump */
1193                 options.proxy_use_fdpass = 0;
1194                 snprintf(port_s, sizeof(port_s), "%d", options.jump_port);
1195                 xasprintf(&options.proxy_command,
1196                     "%s%s%s%s%s%s%s%s%s%s%.*s -W '[%%h]:%%p' %s",
1197                     sshbin,
1198                     /* Optional "-l user" argument if jump_user set */
1199                     options.jump_user == NULL ? "" : " -l ",
1200                     options.jump_user == NULL ? "" : options.jump_user,
1201                     /* Optional "-p port" argument if jump_port set */
1202                     options.jump_port <= 0 ? "" : " -p ",
1203                     options.jump_port <= 0 ? "" : port_s,
1204                     /* Optional additional jump hosts ",..." */
1205                     options.jump_extra == NULL ? "" : " -J ",
1206                     options.jump_extra == NULL ? "" : options.jump_extra,
1207                     /* Optional "-F" argumment if -F specified */
1208                     config == NULL ? "" : " -F ",
1209                     config == NULL ? "" : config,
1210                     /* Optional "-v" arguments if -v set */
1211                     debug_flag ? " -" : "",
1212                     debug_flag, "vvv",
1213                     /* Mandatory hostname */
1214                     options.jump_host);
1215                 debug("Setting implicit ProxyCommand from ProxyJump: %s",
1216                     options.proxy_command);
1217         }
1218
1219         if (options.port == 0)
1220                 options.port = default_ssh_port();
1221         channel_set_af(ssh, options.address_family);
1222
1223         /* Tidy and check options */
1224         if (options.host_key_alias != NULL)
1225                 lowercase(options.host_key_alias);
1226         if (options.proxy_command != NULL &&
1227             strcmp(options.proxy_command, "-") == 0 &&
1228             options.proxy_use_fdpass)
1229                 fatal("ProxyCommand=- and ProxyUseFDPass are incompatible");
1230         if (options.control_persist &&
1231             options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK) {
1232                 debug("UpdateHostKeys=ask is incompatible with ControlPersist; "
1233                     "disabling");
1234                 options.update_hostkeys = 0;
1235         }
1236         if (options.connection_attempts <= 0)
1237                 fatal("Invalid number of ConnectionAttempts");
1238
1239         if (sshbuf_len(command) != 0 && options.remote_command != NULL)
1240                 fatal("Cannot execute command-line and remote command.");
1241
1242         /* Cannot fork to background if no command. */
1243         if (fork_after_authentication_flag && sshbuf_len(command) == 0 &&
1244             options.remote_command == NULL && !no_shell_flag)
1245                 fatal("Cannot fork into background without a command "
1246                     "to execute.");
1247
1248         /* reinit */
1249         log_init(argv0, options.log_level, options.log_facility, !use_syslog);
1250
1251         if (options.request_tty == REQUEST_TTY_YES ||
1252             options.request_tty == REQUEST_TTY_FORCE)
1253                 tty_flag = 1;
1254
1255         /* Allocate a tty by default if no command specified. */
1256         if (sshbuf_len(command) == 0 && options.remote_command == NULL)
1257                 tty_flag = options.request_tty != REQUEST_TTY_NO;
1258
1259         /* Force no tty */
1260         if (options.request_tty == REQUEST_TTY_NO ||
1261             (muxclient_command && muxclient_command != SSHMUX_COMMAND_PROXY))
1262                 tty_flag = 0;
1263         /* Do not allocate a tty if stdin is not a tty. */
1264         if ((!isatty(fileno(stdin)) || stdin_null_flag) &&
1265             options.request_tty != REQUEST_TTY_FORCE) {
1266                 if (tty_flag)
1267                         logit("Pseudo-terminal will not be allocated because "
1268                             "stdin is not a terminal.");
1269                 tty_flag = 0;
1270         }
1271
1272         if (options.user == NULL)
1273                 options.user = xstrdup(pw->pw_name);
1274
1275         /* Set up strings used to percent_expand() arguments */
1276         if (gethostname(thishost, sizeof(thishost)) == -1)
1277                 fatal("gethostname: %s", strerror(errno));
1278         strlcpy(shorthost, thishost, sizeof(shorthost));
1279         shorthost[strcspn(thishost, ".")] = '\0';
1280         snprintf(portstr, sizeof(portstr), "%d", options.port);
1281         snprintf(uidstr, sizeof(uidstr), "%llu",
1282             (unsigned long long)pw->pw_uid);
1283
1284         if ((md = ssh_digest_start(SSH_DIGEST_SHA1)) == NULL ||
1285             ssh_digest_update(md, thishost, strlen(thishost)) < 0 ||
1286             ssh_digest_update(md, host, strlen(host)) < 0 ||
1287             ssh_digest_update(md, portstr, strlen(portstr)) < 0 ||
1288             ssh_digest_update(md, options.user, strlen(options.user)) < 0 ||
1289             ssh_digest_final(md, conn_hash, sizeof(conn_hash)) < 0)
1290                 fatal("%s: mux digest failed", __func__);
1291         ssh_digest_free(md);
1292         conn_hash_hex = tohex(conn_hash, ssh_digest_bytes(SSH_DIGEST_SHA1));
1293
1294         /*
1295          * Expand tokens in arguments. NB. LocalCommand is expanded later,
1296          * after port-forwarding is set up, so it may pick up any local
1297          * tunnel interface name allocated.
1298          */
1299         if (options.remote_command != NULL) {
1300                 debug3("expanding RemoteCommand: %s", options.remote_command);
1301                 cp = options.remote_command;
1302                 options.remote_command = percent_expand(cp,
1303                     "C", conn_hash_hex,
1304                     "L", shorthost,
1305                     "d", pw->pw_dir,
1306                     "h", host,
1307                     "i", uidstr,
1308                     "l", thishost,
1309                     "n", host_arg,
1310                     "p", portstr,
1311                     "r", options.user,
1312                     "u", pw->pw_name,
1313                     (char *)NULL);
1314                 debug3("expanded RemoteCommand: %s", options.remote_command);
1315                 free(cp);
1316                 if ((r = sshbuf_put(command, options.remote_command,
1317                     strlen(options.remote_command))) != 0)
1318                         fatal("%s: buffer error: %s", __func__, ssh_err(r));
1319         }
1320
1321         if (options.control_path != NULL) {
1322                 cp = tilde_expand_filename(options.control_path, getuid());
1323                 free(options.control_path);
1324                 options.control_path = percent_expand(cp,
1325                     "C", conn_hash_hex,
1326                     "L", shorthost,
1327                     "h", host,
1328                     "i", uidstr,
1329                     "l", thishost,
1330                     "n", host_arg,
1331                     "p", portstr,
1332                     "r", options.user,
1333                     "u", pw->pw_name,
1334                     "i", uidstr,
1335                     (char *)NULL);
1336                 free(cp);
1337         }
1338
1339         if (config_test) {
1340                 dump_client_config(&options, host);
1341                 exit(0);
1342         }
1343
1344         if (muxclient_command != 0 && options.control_path == NULL)
1345                 fatal("No ControlPath specified for \"-O\" command");
1346         if (options.control_path != NULL) {
1347                 int sock;
1348                 if ((sock = muxclient(options.control_path)) >= 0) {
1349                         ssh_packet_set_connection(ssh, sock, sock);
1350                         ssh_packet_set_mux(ssh);
1351                         goto skip_connect;
1352                 }
1353         }
1354
1355         /*
1356          * If hostname canonicalisation was not enabled, then we may not
1357          * have yet resolved the hostname. Do so now.
1358          */
1359         if (addrs == NULL && options.proxy_command == NULL) {
1360                 debug2("resolving \"%s\" port %d", host, options.port);
1361                 if ((addrs = resolve_host(host, options.port, 1,
1362                     cname, sizeof(cname))) == NULL)
1363                         cleanup_exit(255); /* resolve_host logs the error */
1364         }
1365
1366         timeout_ms = options.connection_timeout * 1000;
1367
1368         /* Open a connection to the remote host. */
1369         if (ssh_connect(ssh, host, addrs, &hostaddr, options.port,
1370             options.address_family, options.connection_attempts,
1371             &timeout_ms, options.tcp_keep_alive) != 0)
1372                 exit(255);
1373
1374         if (addrs != NULL)
1375                 freeaddrinfo(addrs);
1376
1377         ssh_packet_set_timeout(ssh, options.server_alive_interval,
1378             options.server_alive_count_max);
1379
1380         if (timeout_ms > 0)
1381                 debug3("timeout: %d ms remain after connect", timeout_ms);
1382
1383         /*
1384          * If we successfully made the connection and we have hostbased auth
1385          * enabled, load the public keys so we can later use the ssh-keysign
1386          * helper to sign challenges.
1387          */
1388         sensitive_data.nkeys = 0;
1389         sensitive_data.keys = NULL;
1390         if (options.hostbased_authentication) {
1391                 sensitive_data.nkeys = 10;
1392                 sensitive_data.keys = xcalloc(sensitive_data.nkeys,
1393                     sizeof(struct sshkey));
1394
1395                 /* XXX check errors? */
1396 #define L_PUBKEY(p,o) do { \
1397         if ((o) >= sensitive_data.nkeys) \
1398                 fatal("%s pubkey out of array bounds", __func__); \
1399         check_load(sshkey_load_public(p, &(sensitive_data.keys[o]), NULL), \
1400             p, "pubkey"); \
1401 } while (0)
1402 #define L_CERT(p,o) do { \
1403         if ((o) >= sensitive_data.nkeys) \
1404                 fatal("%s cert out of array bounds", __func__); \
1405         check_load(sshkey_load_cert(p, &(sensitive_data.keys[o])), p, "cert"); \
1406 } while (0)
1407
1408                 if (options.hostbased_authentication == 1) {
1409                         L_CERT(_PATH_HOST_ECDSA_KEY_FILE, 0);
1410                         L_CERT(_PATH_HOST_ED25519_KEY_FILE, 1);
1411                         L_CERT(_PATH_HOST_RSA_KEY_FILE, 2);
1412                         L_CERT(_PATH_HOST_DSA_KEY_FILE, 3);
1413                         L_PUBKEY(_PATH_HOST_ECDSA_KEY_FILE, 4);
1414                         L_PUBKEY(_PATH_HOST_ED25519_KEY_FILE, 5);
1415                         L_PUBKEY(_PATH_HOST_RSA_KEY_FILE, 6);
1416                         L_PUBKEY(_PATH_HOST_DSA_KEY_FILE, 7);
1417                         L_CERT(_PATH_HOST_XMSS_KEY_FILE, 8);
1418                         L_PUBKEY(_PATH_HOST_XMSS_KEY_FILE, 9);
1419                 }
1420         }
1421
1422         /* Create ~/.ssh * directory if it doesn't already exist. */
1423         if (config == NULL) {
1424                 r = snprintf(buf, sizeof buf, "%s%s%s", pw->pw_dir,
1425                     strcmp(pw->pw_dir, "/") ? "/" : "", _PATH_SSH_USER_DIR);
1426                 if (r > 0 && (size_t)r < sizeof(buf) && stat(buf, &st) < 0) {
1427 #ifdef WITH_SELINUX
1428                         ssh_selinux_setfscreatecon(buf);
1429 #endif
1430                         if (mkdir(buf, 0700) < 0)
1431                                 error("Could not create directory '%.200s'.",
1432                                     buf);
1433 #ifdef WITH_SELINUX
1434                         ssh_selinux_setfscreatecon(NULL);
1435 #endif
1436                 }
1437         }
1438         /* load options.identity_files */
1439         load_public_identity_files(pw);
1440
1441         /* optionally set the SSH_AUTHSOCKET_ENV_NAME variable */
1442         if (options.identity_agent &&
1443             strcmp(options.identity_agent, SSH_AUTHSOCKET_ENV_NAME) != 0) {
1444                 if (strcmp(options.identity_agent, "none") == 0) {
1445                         unsetenv(SSH_AUTHSOCKET_ENV_NAME);
1446                 } else {
1447                         p = tilde_expand_filename(options.identity_agent,
1448                             getuid());
1449                         cp = percent_expand(p,
1450                             "d", pw->pw_dir,
1451                             "h", host,
1452                             "i", uidstr,
1453                             "l", thishost,
1454                             "r", options.user,
1455                             "u", pw->pw_name,
1456                             (char *)NULL);
1457                         free(p);
1458                         /*
1459                          * If identity_agent represents an environment variable
1460                          * then recheck that it is valid (since processing with
1461                          * percent_expand() may have changed it) and substitute
1462                          * its value.
1463                          */
1464                         if (cp[0] == '$') {
1465                                 if (!valid_env_name(cp + 1)) {
1466                                         fatal("Invalid IdentityAgent "
1467                                             "environment variable name %s", cp);
1468                                 }
1469                                 if ((p = getenv(cp + 1)) == NULL)
1470                                         unsetenv(SSH_AUTHSOCKET_ENV_NAME);
1471                                 else
1472                                         setenv(SSH_AUTHSOCKET_ENV_NAME, p, 1);
1473                         } else {
1474                                 /* identity_agent specifies a path directly */
1475                                 setenv(SSH_AUTHSOCKET_ENV_NAME, cp, 1);
1476                         }
1477                         free(cp);
1478                 }
1479         }
1480
1481         /* Expand ~ in known host file names. */
1482         tilde_expand_paths(options.system_hostfiles,
1483             options.num_system_hostfiles);
1484         tilde_expand_paths(options.user_hostfiles, options.num_user_hostfiles);
1485
1486         signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */
1487         signal(SIGCHLD, main_sigchld_handler);
1488
1489         /* Log into the remote system.  Never returns if the login fails. */
1490         ssh_login(ssh, &sensitive_data, host, (struct sockaddr *)&hostaddr,
1491             options.port, pw, timeout_ms);
1492
1493         if (ssh_packet_connection_is_on_socket(ssh)) {
1494                 verbose("Authenticated to %s ([%s]:%d).", host,
1495                     ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
1496         } else {
1497                 verbose("Authenticated to %s (via proxy).", host);
1498         }
1499
1500         /* We no longer need the private host keys.  Clear them now. */
1501         if (sensitive_data.nkeys != 0) {
1502                 for (i = 0; i < sensitive_data.nkeys; i++) {
1503                         if (sensitive_data.keys[i] != NULL) {
1504                                 /* Destroys contents safely */
1505                                 debug3("clear hostkey %d", i);
1506                                 sshkey_free(sensitive_data.keys[i]);
1507                                 sensitive_data.keys[i] = NULL;
1508                         }
1509                 }
1510                 free(sensitive_data.keys);
1511         }
1512         for (i = 0; i < options.num_identity_files; i++) {
1513                 free(options.identity_files[i]);
1514                 options.identity_files[i] = NULL;
1515                 if (options.identity_keys[i]) {
1516                         sshkey_free(options.identity_keys[i]);
1517                         options.identity_keys[i] = NULL;
1518                 }
1519         }
1520         for (i = 0; i < options.num_certificate_files; i++) {
1521                 free(options.certificate_files[i]);
1522                 options.certificate_files[i] = NULL;
1523         }
1524
1525  skip_connect:
1526         exit_status = ssh_session2(ssh, pw);
1527         ssh_packet_close(ssh);
1528
1529         if (options.control_path != NULL && muxserver_sock != -1)
1530                 unlink(options.control_path);
1531
1532         /* Kill ProxyCommand if it is running. */
1533         ssh_kill_proxy_command();
1534
1535         return exit_status;
1536 }
1537
1538 static void
1539 control_persist_detach(void)
1540 {
1541         pid_t pid;
1542         int devnull, keep_stderr;
1543
1544         debug("%s: backgrounding master process", __func__);
1545
1546         /*
1547          * master (current process) into the background, and make the
1548          * foreground process a client of the backgrounded master.
1549          */
1550         switch ((pid = fork())) {
1551         case -1:
1552                 fatal("%s: fork: %s", __func__, strerror(errno));
1553         case 0:
1554                 /* Child: master process continues mainloop */
1555                 break;
1556         default:
1557                 /* Parent: set up mux slave to connect to backgrounded master */
1558                 debug2("%s: background process is %ld", __func__, (long)pid);
1559                 stdin_null_flag = ostdin_null_flag;
1560                 options.request_tty = orequest_tty;
1561                 tty_flag = otty_flag;
1562                 close(muxserver_sock);
1563                 muxserver_sock = -1;
1564                 options.control_master = SSHCTL_MASTER_NO;
1565                 muxclient(options.control_path);
1566                 /* muxclient() doesn't return on success. */
1567                 fatal("Failed to connect to new control master");
1568         }
1569         if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1) {
1570                 error("%s: open(\"/dev/null\"): %s", __func__,
1571                     strerror(errno));
1572         } else {
1573                 keep_stderr = log_is_on_stderr() && debug_flag;
1574                 if (dup2(devnull, STDIN_FILENO) == -1 ||
1575                     dup2(devnull, STDOUT_FILENO) == -1 ||
1576                     (!keep_stderr && dup2(devnull, STDERR_FILENO) == -1))
1577                         error("%s: dup2: %s", __func__, strerror(errno));
1578                 if (devnull > STDERR_FILENO)
1579                         close(devnull);
1580         }
1581         daemon(1, 1);
1582         setproctitle("%s [mux]", options.control_path);
1583 }
1584
1585 /* Do fork() after authentication. Used by "ssh -f" */
1586 static void
1587 fork_postauth(void)
1588 {
1589         if (need_controlpersist_detach)
1590                 control_persist_detach();
1591         debug("forking to background");
1592         fork_after_authentication_flag = 0;
1593         if (daemon(1, 1) < 0)
1594                 fatal("daemon() failed: %.200s", strerror(errno));
1595 }
1596
1597 /* Callback for remote forward global requests */
1598 static void
1599 ssh_confirm_remote_forward(struct ssh *ssh, int type, u_int32_t seq, void *ctxt)
1600 {
1601         struct Forward *rfwd = (struct Forward *)ctxt;
1602         u_int port;
1603         int r;
1604
1605         /* XXX verbose() on failure? */
1606         debug("remote forward %s for: listen %s%s%d, connect %s:%d",
1607             type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure",
1608             rfwd->listen_path ? rfwd->listen_path :
1609             rfwd->listen_host ? rfwd->listen_host : "",
1610             (rfwd->listen_path || rfwd->listen_host) ? ":" : "",
1611             rfwd->listen_port, rfwd->connect_path ? rfwd->connect_path :
1612             rfwd->connect_host, rfwd->connect_port);
1613         if (rfwd->listen_path == NULL && rfwd->listen_port == 0) {
1614                 if (type == SSH2_MSG_REQUEST_SUCCESS) {
1615                         if ((r = sshpkt_get_u32(ssh, &port)) != 0)
1616                                 fatal("%s: %s", __func__, ssh_err(r));
1617                         if (port > 65535) {
1618                                 error("Invalid allocated port %u for remote "
1619                                     "forward to %s:%d", port,
1620                                     rfwd->connect_host, rfwd->connect_port);
1621                                 /* Ensure failure processing runs below */
1622                                 type = SSH2_MSG_REQUEST_FAILURE;
1623                                 channel_update_permission(ssh,
1624                                     rfwd->handle, -1);
1625                         } else {
1626                                 rfwd->allocated_port = (int)port;
1627                                 logit("Allocated port %u for remote "
1628                                     "forward to %s:%d",
1629                                     rfwd->allocated_port, rfwd->connect_host,
1630                                     rfwd->connect_port);
1631                                 channel_update_permission(ssh,
1632                                     rfwd->handle, rfwd->allocated_port);
1633                         }
1634                 } else {
1635                         channel_update_permission(ssh, rfwd->handle, -1);
1636                 }
1637         }
1638
1639         if (type == SSH2_MSG_REQUEST_FAILURE) {
1640                 if (options.exit_on_forward_failure) {
1641                         if (rfwd->listen_path != NULL)
1642                                 fatal("Error: remote port forwarding failed "
1643                                     "for listen path %s", rfwd->listen_path);
1644                         else
1645                                 fatal("Error: remote port forwarding failed "
1646                                     "for listen port %d", rfwd->listen_port);
1647                 } else {
1648                         if (rfwd->listen_path != NULL)
1649                                 logit("Warning: remote port forwarding failed "
1650                                     "for listen path %s", rfwd->listen_path);
1651                         else
1652                                 logit("Warning: remote port forwarding failed "
1653                                     "for listen port %d", rfwd->listen_port);
1654                 }
1655         }
1656         if (++remote_forward_confirms_received == options.num_remote_forwards) {
1657                 debug("All remote forwarding requests processed");
1658                 if (fork_after_authentication_flag)
1659                         fork_postauth();
1660         }
1661 }
1662
1663 static void
1664 client_cleanup_stdio_fwd(struct ssh *ssh, int id, void *arg)
1665 {
1666         debug("stdio forwarding: done");
1667         cleanup_exit(0);
1668 }
1669
1670 static void
1671 ssh_stdio_confirm(struct ssh *ssh, int id, int success, void *arg)
1672 {
1673         if (!success)
1674                 fatal("stdio forwarding failed");
1675 }
1676
1677 static void
1678 ssh_init_stdio_forwarding(struct ssh *ssh)
1679 {
1680         Channel *c;
1681         int in, out;
1682
1683         if (options.stdio_forward_host == NULL)
1684                 return;
1685
1686         debug3("%s: %s:%d", __func__, options.stdio_forward_host,
1687             options.stdio_forward_port);
1688
1689         if ((in = dup(STDIN_FILENO)) < 0 ||
1690             (out = dup(STDOUT_FILENO)) < 0)
1691                 fatal("channel_connect_stdio_fwd: dup() in/out failed");
1692         if ((c = channel_connect_stdio_fwd(ssh, options.stdio_forward_host,
1693             options.stdio_forward_port, in, out)) == NULL)
1694                 fatal("%s: channel_connect_stdio_fwd failed", __func__);
1695         channel_register_cleanup(ssh, c->self, client_cleanup_stdio_fwd, 0);
1696         channel_register_open_confirm(ssh, c->self, ssh_stdio_confirm, NULL);
1697 }
1698
1699 static void
1700 ssh_init_forwarding(struct ssh *ssh, char **ifname)
1701 {
1702         int success = 0;
1703         int i;
1704
1705         /* Initiate local TCP/IP port forwardings. */
1706         for (i = 0; i < options.num_local_forwards; i++) {
1707                 debug("Local connections to %.200s:%d forwarded to remote "
1708                     "address %.200s:%d",
1709                     (options.local_forwards[i].listen_path != NULL) ?
1710                     options.local_forwards[i].listen_path :
1711                     (options.local_forwards[i].listen_host == NULL) ?
1712                     (options.fwd_opts.gateway_ports ? "*" : "LOCALHOST") :
1713                     options.local_forwards[i].listen_host,
1714                     options.local_forwards[i].listen_port,
1715                     (options.local_forwards[i].connect_path != NULL) ?
1716                     options.local_forwards[i].connect_path :
1717                     options.local_forwards[i].connect_host,
1718                     options.local_forwards[i].connect_port);
1719                 success += channel_setup_local_fwd_listener(ssh,
1720                     &options.local_forwards[i], &options.fwd_opts);
1721         }
1722         if (i > 0 && success != i && options.exit_on_forward_failure)
1723                 fatal("Could not request local forwarding.");
1724         if (i > 0 && success == 0)
1725                 error("Could not request local forwarding.");
1726
1727         /* Initiate remote TCP/IP port forwardings. */
1728         for (i = 0; i < options.num_remote_forwards; i++) {
1729                 debug("Remote connections from %.200s:%d forwarded to "
1730                     "local address %.200s:%d",
1731                     (options.remote_forwards[i].listen_path != NULL) ?
1732                     options.remote_forwards[i].listen_path :
1733                     (options.remote_forwards[i].listen_host == NULL) ?
1734                     "LOCALHOST" : options.remote_forwards[i].listen_host,
1735                     options.remote_forwards[i].listen_port,
1736                     (options.remote_forwards[i].connect_path != NULL) ?
1737                     options.remote_forwards[i].connect_path :
1738                     options.remote_forwards[i].connect_host,
1739                     options.remote_forwards[i].connect_port);
1740                 options.remote_forwards[i].handle =
1741                     channel_request_remote_forwarding(ssh,
1742                     &options.remote_forwards[i]);
1743                 if (options.remote_forwards[i].handle < 0) {
1744                         if (options.exit_on_forward_failure)
1745                                 fatal("Could not request remote forwarding.");
1746                         else
1747                                 logit("Warning: Could not request remote "
1748                                     "forwarding.");
1749                 } else {
1750                         client_register_global_confirm(
1751                             ssh_confirm_remote_forward,
1752                             &options.remote_forwards[i]);
1753                 }
1754         }
1755
1756         /* Initiate tunnel forwarding. */
1757         if (options.tun_open != SSH_TUNMODE_NO) {
1758                 if ((*ifname = client_request_tun_fwd(ssh,
1759                     options.tun_open, options.tun_local,
1760                     options.tun_remote)) == NULL) {
1761                         if (options.exit_on_forward_failure)
1762                                 fatal("Could not request tunnel forwarding.");
1763                         else
1764                                 error("Could not request tunnel forwarding.");
1765                 }
1766         }
1767 }
1768
1769 static void
1770 check_agent_present(void)
1771 {
1772         int r;
1773
1774         if (options.forward_agent) {
1775                 /* Clear agent forwarding if we don't have an agent. */
1776                 if ((r = ssh_get_authentication_socket(NULL)) != 0) {
1777                         options.forward_agent = 0;
1778                         if (r != SSH_ERR_AGENT_NOT_PRESENT)
1779                                 debug("ssh_get_authentication_socket: %s",
1780                                     ssh_err(r));
1781                 }
1782         }
1783 }
1784
1785 static void
1786 ssh_session2_setup(struct ssh *ssh, int id, int success, void *arg)
1787 {
1788         extern char **environ;
1789         const char *display;
1790         int r, interactive = tty_flag;
1791         char *proto = NULL, *data = NULL;
1792
1793         if (!success)
1794                 return; /* No need for error message, channels code sens one */
1795
1796         display = getenv("DISPLAY");
1797         if (display == NULL && options.forward_x11)
1798                 debug("X11 forwarding requested but DISPLAY not set");
1799         if (options.forward_x11 && client_x11_get_proto(ssh, display,
1800             options.xauth_location, options.forward_x11_trusted,
1801             options.forward_x11_timeout, &proto, &data) == 0) {
1802                 /* Request forwarding with authentication spoofing. */
1803                 debug("Requesting X11 forwarding with authentication "
1804                     "spoofing.");
1805                 x11_request_forwarding_with_spoofing(ssh, id, display, proto,
1806                     data, 1);
1807                 client_expect_confirm(ssh, id, "X11 forwarding", CONFIRM_WARN);
1808                 /* XXX exit_on_forward_failure */
1809                 interactive = 1;
1810         }
1811
1812         check_agent_present();
1813         if (options.forward_agent) {
1814                 debug("Requesting authentication agent forwarding.");
1815                 channel_request_start(ssh, id, "auth-agent-req@openssh.com", 0);
1816                 if ((r = sshpkt_send(ssh)) != 0)
1817                         fatal("%s: %s", __func__, ssh_err(r));
1818         }
1819
1820         /* Tell the packet module whether this is an interactive session. */
1821         ssh_packet_set_interactive(ssh, interactive,
1822             options.ip_qos_interactive, options.ip_qos_bulk);
1823
1824         client_session2_setup(ssh, id, tty_flag, subsystem_flag, getenv("TERM"),
1825             NULL, fileno(stdin), command, environ);
1826 }
1827
1828 /* open new channel for a session */
1829 static int
1830 ssh_session2_open(struct ssh *ssh)
1831 {
1832         Channel *c;
1833         int window, packetmax, in, out, err;
1834
1835         if (stdin_null_flag) {
1836                 in = open(_PATH_DEVNULL, O_RDONLY);
1837         } else {
1838                 in = dup(STDIN_FILENO);
1839         }
1840         out = dup(STDOUT_FILENO);
1841         err = dup(STDERR_FILENO);
1842
1843         if (in < 0 || out < 0 || err < 0)
1844                 fatal("dup() in/out/err failed");
1845
1846         /* enable nonblocking unless tty */
1847         if (!isatty(in))
1848                 set_nonblock(in);
1849         if (!isatty(out))
1850                 set_nonblock(out);
1851         if (!isatty(err))
1852                 set_nonblock(err);
1853
1854         window = CHAN_SES_WINDOW_DEFAULT;
1855         packetmax = CHAN_SES_PACKET_DEFAULT;
1856         if (tty_flag) {
1857                 window >>= 1;
1858                 packetmax >>= 1;
1859         }
1860         c = channel_new(ssh,
1861             "session", SSH_CHANNEL_OPENING, in, out, err,
1862             window, packetmax, CHAN_EXTENDED_WRITE,
1863             "client-session", /*nonblock*/0);
1864
1865         debug3("%s: channel_new: %d", __func__, c->self);
1866
1867         channel_send_open(ssh, c->self);
1868         if (!no_shell_flag)
1869                 channel_register_open_confirm(ssh, c->self,
1870                     ssh_session2_setup, NULL);
1871
1872         return c->self;
1873 }
1874
1875 static int
1876 ssh_session2(struct ssh *ssh, struct passwd *pw)
1877 {
1878         int r, devnull, id = -1;
1879         char *cp, *tun_fwd_ifname = NULL;
1880
1881         /* XXX should be pre-session */
1882         if (!options.control_persist)
1883                 ssh_init_stdio_forwarding(ssh);
1884
1885         ssh_init_forwarding(ssh, &tun_fwd_ifname);
1886
1887         if (options.local_command != NULL) {
1888                 debug3("expanding LocalCommand: %s", options.local_command);
1889                 cp = options.local_command;
1890                 options.local_command = percent_expand(cp,
1891                     "C", conn_hash_hex,
1892                     "L", shorthost,
1893                     "d", pw->pw_dir,
1894                     "h", host,
1895                     "i", uidstr,
1896                     "l", thishost,
1897                     "n", host_arg,
1898                     "p", portstr,
1899                     "r", options.user,
1900                     "u", pw->pw_name,
1901                     "T", tun_fwd_ifname == NULL ? "NONE" : tun_fwd_ifname,
1902                     (char *)NULL);
1903                 debug3("expanded LocalCommand: %s", options.local_command);
1904                 free(cp);
1905         }
1906
1907         /* Start listening for multiplex clients */
1908         if (!ssh_packet_get_mux(ssh))
1909                 muxserver_listen(ssh);
1910
1911         /*
1912          * If we are in control persist mode and have a working mux listen
1913          * socket, then prepare to background ourselves and have a foreground
1914          * client attach as a control slave.
1915          * NB. we must save copies of the flags that we override for
1916          * the backgrounding, since we defer attachment of the slave until
1917          * after the connection is fully established (in particular,
1918          * async rfwd replies have been received for ExitOnForwardFailure).
1919          */
1920         if (options.control_persist && muxserver_sock != -1) {
1921                 ostdin_null_flag = stdin_null_flag;
1922                 ono_shell_flag = no_shell_flag;
1923                 orequest_tty = options.request_tty;
1924                 otty_flag = tty_flag;
1925                 stdin_null_flag = 1;
1926                 no_shell_flag = 1;
1927                 tty_flag = 0;
1928                 if (!fork_after_authentication_flag)
1929                         need_controlpersist_detach = 1;
1930                 fork_after_authentication_flag = 1;
1931         }
1932         /*
1933          * ControlPersist mux listen socket setup failed, attempt the
1934          * stdio forward setup that we skipped earlier.
1935          */
1936         if (options.control_persist && muxserver_sock == -1)
1937                 ssh_init_stdio_forwarding(ssh);
1938
1939         if (!no_shell_flag)
1940                 id = ssh_session2_open(ssh);
1941         else {
1942                 ssh_packet_set_interactive(ssh,
1943                     options.control_master == SSHCTL_MASTER_NO,
1944                     options.ip_qos_interactive, options.ip_qos_bulk);
1945         }
1946
1947         /* If we don't expect to open a new session, then disallow it */
1948         if (options.control_master == SSHCTL_MASTER_NO &&
1949             (datafellows & SSH_NEW_OPENSSH)) {
1950                 debug("Requesting no-more-sessions@openssh.com");
1951                 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 ||
1952                     (r = sshpkt_put_cstring(ssh,
1953                     "no-more-sessions@openssh.com")) != 0 ||
1954                     (r = sshpkt_put_u8(ssh, 0)) != 0 ||
1955                     (r = sshpkt_send(ssh)) != 0)
1956                         fatal("%s: %s", __func__, ssh_err(r));
1957         }
1958
1959         /* Execute a local command */
1960         if (options.local_command != NULL &&
1961             options.permit_local_command)
1962                 ssh_local_cmd(options.local_command);
1963
1964         /*
1965          * stdout is now owned by the session channel; clobber it here
1966          * so future channel closes are propagated to the local fd.
1967          * NB. this can only happen after LocalCommand has completed,
1968          * as it may want to write to stdout.
1969          */
1970         if (!need_controlpersist_detach) {
1971                 if ((devnull = open(_PATH_DEVNULL, O_WRONLY)) == -1)
1972                         error("%s: open %s: %s", __func__,
1973                             _PATH_DEVNULL, strerror(errno));
1974                 if (dup2(devnull, STDOUT_FILENO) < 0)
1975                         fatal("%s: dup2() stdout failed", __func__);
1976                 if (devnull > STDERR_FILENO)
1977                         close(devnull);
1978         }
1979
1980         /*
1981          * If requested and we are not interested in replies to remote
1982          * forwarding requests, then let ssh continue in the background.
1983          */
1984         if (fork_after_authentication_flag) {
1985                 if (options.exit_on_forward_failure &&
1986                     options.num_remote_forwards > 0) {
1987                         debug("deferring postauth fork until remote forward "
1988                             "confirmation received");
1989                 } else
1990                         fork_postauth();
1991         }
1992
1993         return client_loop(ssh, tty_flag, tty_flag ?
1994             options.escape_char : SSH_ESCAPECHAR_NONE, id);
1995 }
1996
1997 /* Loads all IdentityFile and CertificateFile keys */
1998 static void
1999 load_public_identity_files(struct passwd *pw)
2000 {
2001         char *filename, *cp;
2002         struct sshkey *public;
2003         int i;
2004         u_int n_ids, n_certs;
2005         char *identity_files[SSH_MAX_IDENTITY_FILES];
2006         struct sshkey *identity_keys[SSH_MAX_IDENTITY_FILES];
2007         int identity_file_userprovided[SSH_MAX_IDENTITY_FILES];
2008         char *certificate_files[SSH_MAX_CERTIFICATE_FILES];
2009         struct sshkey *certificates[SSH_MAX_CERTIFICATE_FILES];
2010         int certificate_file_userprovided[SSH_MAX_CERTIFICATE_FILES];
2011 #ifdef ENABLE_PKCS11
2012         struct sshkey **keys;
2013         int nkeys;
2014 #endif /* PKCS11 */
2015
2016         n_ids = n_certs = 0;
2017         memset(identity_files, 0, sizeof(identity_files));
2018         memset(identity_keys, 0, sizeof(identity_keys));
2019         memset(identity_file_userprovided, 0,
2020             sizeof(identity_file_userprovided));
2021         memset(certificate_files, 0, sizeof(certificate_files));
2022         memset(certificates, 0, sizeof(certificates));
2023         memset(certificate_file_userprovided, 0,
2024             sizeof(certificate_file_userprovided));
2025
2026 #ifdef ENABLE_PKCS11
2027         if (options.pkcs11_provider != NULL &&
2028             options.num_identity_files < SSH_MAX_IDENTITY_FILES &&
2029             (pkcs11_init(!options.batch_mode) == 0) &&
2030             (nkeys = pkcs11_add_provider(options.pkcs11_provider, NULL,
2031             &keys)) > 0) {
2032                 for (i = 0; i < nkeys; i++) {
2033                         if (n_ids >= SSH_MAX_IDENTITY_FILES) {
2034                                 sshkey_free(keys[i]);
2035                                 continue;
2036                         }
2037                         identity_keys[n_ids] = keys[i];
2038                         identity_files[n_ids] =
2039                             xstrdup(options.pkcs11_provider); /* XXX */
2040                         n_ids++;
2041                 }
2042                 free(keys);
2043         }
2044 #endif /* ENABLE_PKCS11 */
2045         for (i = 0; i < options.num_identity_files; i++) {
2046                 if (n_ids >= SSH_MAX_IDENTITY_FILES ||
2047                     strcasecmp(options.identity_files[i], "none") == 0) {
2048                         free(options.identity_files[i]);
2049                         options.identity_files[i] = NULL;
2050                         continue;
2051                 }
2052                 cp = tilde_expand_filename(options.identity_files[i], getuid());
2053                 filename = percent_expand(cp, "d", pw->pw_dir,
2054                     "u", pw->pw_name, "l", thishost, "h", host,
2055                     "r", options.user, (char *)NULL);
2056                 free(cp);
2057                 check_load(sshkey_load_public(filename, &public, NULL),
2058                     filename, "pubkey");
2059                 debug("identity file %s type %d", filename,
2060                     public ? public->type : -1);
2061                 free(options.identity_files[i]);
2062                 identity_files[n_ids] = filename;
2063                 identity_keys[n_ids] = public;
2064                 identity_file_userprovided[n_ids] =
2065                     options.identity_file_userprovided[i];
2066                 if (++n_ids >= SSH_MAX_IDENTITY_FILES)
2067                         continue;
2068
2069                 /*
2070                  * If no certificates have been explicitly listed then try
2071                  * to add the default certificate variant too.
2072                  */
2073                 if (options.num_certificate_files != 0)
2074                         continue;
2075                 xasprintf(&cp, "%s-cert", filename);
2076                 check_load(sshkey_load_public(cp, &public, NULL),
2077                     filename, "pubkey");
2078                 debug("identity file %s type %d", cp,
2079                     public ? public->type : -1);
2080                 if (public == NULL) {
2081                         free(cp);
2082                         continue;
2083                 }
2084                 if (!sshkey_is_cert(public)) {
2085                         debug("%s: key %s type %s is not a certificate",
2086                             __func__, cp, sshkey_type(public));
2087                         sshkey_free(public);
2088                         free(cp);
2089                         continue;
2090                 }
2091                 /* NB. leave filename pointing to private key */
2092                 identity_files[n_ids] = xstrdup(filename);
2093                 identity_keys[n_ids] = public;
2094                 identity_file_userprovided[n_ids] =
2095                     options.identity_file_userprovided[i];
2096                 n_ids++;
2097         }
2098
2099         if (options.num_certificate_files > SSH_MAX_CERTIFICATE_FILES)
2100                 fatal("%s: too many certificates", __func__);
2101         for (i = 0; i < options.num_certificate_files; i++) {
2102                 cp = tilde_expand_filename(options.certificate_files[i],
2103                     getuid());
2104                 filename = percent_expand(cp,
2105                     "d", pw->pw_dir,
2106                     "h", host,
2107                     "i", uidstr,
2108                     "l", thishost,
2109                     "r", options.user,
2110                     "u", pw->pw_name,
2111                     (char *)NULL);
2112                 free(cp);
2113
2114                 check_load(sshkey_load_public(filename, &public, NULL),
2115                     filename, "certificate");
2116                 debug("certificate file %s type %d", filename,
2117                     public ? public->type : -1);
2118                 free(options.certificate_files[i]);
2119                 options.certificate_files[i] = NULL;
2120                 if (public == NULL) {
2121                         free(filename);
2122                         continue;
2123                 }
2124                 if (!sshkey_is_cert(public)) {
2125                         debug("%s: key %s type %s is not a certificate",
2126                             __func__, filename, sshkey_type(public));
2127                         sshkey_free(public);
2128                         free(filename);
2129                         continue;
2130                 }
2131                 certificate_files[n_certs] = filename;
2132                 certificates[n_certs] = public;
2133                 certificate_file_userprovided[n_certs] =
2134                     options.certificate_file_userprovided[i];
2135                 ++n_certs;
2136         }
2137
2138         options.num_identity_files = n_ids;
2139         memcpy(options.identity_files, identity_files, sizeof(identity_files));
2140         memcpy(options.identity_keys, identity_keys, sizeof(identity_keys));
2141         memcpy(options.identity_file_userprovided,
2142             identity_file_userprovided, sizeof(identity_file_userprovided));
2143
2144         options.num_certificate_files = n_certs;
2145         memcpy(options.certificate_files,
2146             certificate_files, sizeof(certificate_files));
2147         memcpy(options.certificates, certificates, sizeof(certificates));
2148         memcpy(options.certificate_file_userprovided,
2149             certificate_file_userprovided,
2150             sizeof(certificate_file_userprovided));
2151 }
2152
2153 static void
2154 main_sigchld_handler(int sig)
2155 {
2156         int save_errno = errno;
2157         pid_t pid;
2158         int status;
2159
2160         while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
2161             (pid < 0 && errno == EINTR))
2162                 ;
2163         errno = save_errno;
2164 }