crypto/openssh/ssh.c

   1 /* $OpenBSD: ssh.c,v 1.569 2021/09/20 04:02:13 dtucker Exp $ */
   2 /*
   3  * Author: Tatu Ylonen <ylo@cs.hut.fi>
   4  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
   5  *                    All rights reserved
   6  * Ssh client program.  This program can be used to log into a remote machine.
   7  * The software supports strong authentication, encryption, and forwarding
   8  * of X11, TCP/IP, and authentication connections.
   9  *
  10  * As far as I am concerned, the code I have written for this software
  11  * can be used freely for any purpose.  Any derived versions of this
  12  * software must be clearly marked as such, and if the derived work is
  13  * incompatible with the protocol description in the RFC file, it must be
  14  * called by a name other than "ssh" or "Secure Shell".
  15  *
  16  * Copyright (c) 1999 Niels Provos.  All rights reserved.
  17  * Copyright (c) 2000, 2001, 2002, 2003 Markus Friedl.  All rights reserved.
  18  *
  19  * Modified to work with SSLeay 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 <stdarg.h>
  69 #include <unistd.h>
  70 #include <limits.h>
  71 #include <locale.h>
  72
  73 #include <netinet/in.h>
  74 #include <arpa/inet.h>
  75
  76 #ifdef WITH_OPENSSL
  77 #include <openssl/evp.h>
  78 #include <openssl/err.h>
  79 #endif
  80 #include "openbsd-compat/openssl-compat.h"
  81 #include "openbsd-compat/sys-queue.h"
  82
  83 #include "xmalloc.h"
  84 #include "ssh.h"
  85 #include "ssh2.h"
  86 #include "canohost.h"
  87 #include "compat.h"
  88 #include "cipher.h"
  89 #include "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 /*
 130  * Flag indicating that the current process should be backgrounded and
 131  * a new mux-client launched in the foreground for ControlPersist.
 132  */
 133 int need_controlpersist_detach = 0;
 134
 135 /* Copies of flags for ControlPersist foreground mux-client */
 136 int ostdin_null_flag, osession_type, otty_flag, orequest_tty;
 137
 138 /*
 139  * General data structure for command line options and options configurable
 140  * in configuration files.  See readconf.h.
 141  */
 142 Options options;
 143
 144 /* optional user configfile */
 145 char *config = NULL;
 146
 147 /*
 148  * Name of the host we are connecting to.  This is the name given on the
 149  * command line, or the Hostname specified for the user-supplied name in a
 150  * configuration file.
 151  */
 152 char *host;
 153
 154 /*
 155  * A config can specify a path to forward, overriding SSH_AUTH_SOCK. If this is
 156  * not NULL, forward the socket at this path instead.
 157  */
 158 char *forward_agent_sock_path = NULL;
 159
 160 /* socket address the host resolves to */
 161 struct sockaddr_storage hostaddr;
 162
 163 /* Private host keys. */
 164 Sensitive sensitive_data;
 165
 166 /* command to be executed */
 167 struct sshbuf *command;
 168
 169 /* # of replies received for global requests */
 170 static int forward_confirms_pending = -1;
 171
 172 /* mux.c */
 173 extern int muxserver_sock;
 174 extern u_int muxclient_command;
 175
 176 /* Prints a help message to the user.  This function never returns. */
 177
 178 static void
 179 usage(void)
 180 {
 181         fprintf(stderr,
 182 "usage: ssh [-46AaCfGgKkMNnqsTtVvXxYy] [-B bind_interface]\n"
 183 "           [-b bind_address] [-c cipher_spec] [-D [bind_address:]port]\n"
 184 "           [-E log_file] [-e escape_char] [-F configfile] [-I pkcs11]\n"
 185 "           [-i identity_file] [-J [user@]host[:port]] [-L address]\n"
 186 "           [-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port]\n"
 187 "           [-Q query_option] [-R address] [-S ctl_path] [-W host:port]\n"
 188 "           [-w local_tun[:remote_tun]] destination [command [argument ...]]\n"
 189         );
 190         exit(255);
 191 }
 192
 193 static int ssh_session2(struct ssh *, const struct ssh_conn_info *);
 194 static void load_public_identity_files(const struct ssh_conn_info *);
 195 static void main_sigchld_handler(int);
 196
 197 /* ~/ expand a list of paths. NB. assumes path[n] is heap-allocated. */
 198 static void
 199 tilde_expand_paths(char **paths, u_int num_paths)
 200 {
 201         u_int i;
 202         char *cp;
 203
 204         for (i = 0; i < num_paths; i++) {
 205                 cp = tilde_expand_filename(paths[i], getuid());
 206                 free(paths[i]);
 207                 paths[i] = cp;
 208         }
 209 }
 210
 211 /*
 212  * Expands the set of percent_expand options used by the majority of keywords
 213  * in the client that support percent expansion.
 214  * Caller must free returned string.
 215  */
 216 static char *
 217 default_client_percent_expand(const char *str,
 218     const struct ssh_conn_info *cinfo)
 219 {
 220         return percent_expand(str,
 221             DEFAULT_CLIENT_PERCENT_EXPAND_ARGS(cinfo),
 222             (char *)NULL);
 223 }
 224
 225 /*
 226  * Expands the set of percent_expand options used by the majority of keywords
 227  * AND perform environment variable substitution.
 228  * Caller must free returned string.
 229  */
 230 static char *
 231 default_client_percent_dollar_expand(const char *str,
 232     const struct ssh_conn_info *cinfo)
 233 {
 234         char *ret;
 235
 236         ret = percent_dollar_expand(str,
 237             DEFAULT_CLIENT_PERCENT_EXPAND_ARGS(cinfo),
 238             (char *)NULL);
 239         if (ret == NULL)
 240                 fatal("invalid environment variable expansion");
 241         return ret;
 242 }
 243
 244 /*
 245  * Attempt to resolve a host name / port to a set of addresses and
 246  * optionally return any CNAMEs encountered along the way.
 247  * Returns NULL on failure.
 248  * NB. this function must operate with a options having undefined members.
 249  */
 250 static struct addrinfo *
 251 resolve_host(const char *name, int port, int logerr, char *cname, size_t clen)
 252 {
 253         char strport[NI_MAXSERV];
 254         struct addrinfo hints, *res;
 255         int gaierr;
 256         LogLevel loglevel = SYSLOG_LEVEL_DEBUG1;
 257
 258         if (port <= 0)
 259                 port = default_ssh_port();
 260         if (cname != NULL)
 261                 *cname = '\0';
 262         debug3_f("lookup %s:%d", name, port);
 263
 264         snprintf(strport, sizeof strport, "%d", port);
 265         memset(&hints, 0, sizeof(hints));
 266         hints.ai_family = options.address_family == -1 ?
 267             AF_UNSPEC : options.address_family;
 268         hints.ai_socktype = SOCK_STREAM;
 269         if (cname != NULL)
 270                 hints.ai_flags = AI_CANONNAME;
 271         if ((gaierr = getaddrinfo(name, strport, &hints, &res)) != 0) {
 272                 if (logerr || (gaierr != EAI_NONAME && gaierr != EAI_NODATA))
 273                         loglevel = SYSLOG_LEVEL_ERROR;
 274                 do_log2(loglevel, "%s: Could not resolve hostname %.100s: %s",
 275                     __progname, name, ssh_gai_strerror(gaierr));
 276                 return NULL;
 277         }
 278         if (cname != NULL && res->ai_canonname != NULL) {
 279                 if (strlcpy(cname, res->ai_canonname, clen) >= clen) {
 280                         error_f("host \"%s\" cname \"%s\" too long (max %lu)",
 281                             name,  res->ai_canonname, (u_long)clen);
 282                         if (clen > 0)
 283                                 *cname = '\0';
 284                 }
 285         }
 286         return res;
 287 }
 288
 289 /* Returns non-zero if name can only be an address and not a hostname */
 290 static int
 291 is_addr_fast(const char *name)
 292 {
 293         return (strchr(name, '%') != NULL || strchr(name, ':') != NULL ||
 294             strspn(name, "0123456789.") == strlen(name));
 295 }
 296
 297 /* Returns non-zero if name represents a valid, single address */
 298 static int
 299 is_addr(const char *name)
 300 {
 301         char strport[NI_MAXSERV];
 302         struct addrinfo hints, *res;
 303
 304         if (is_addr_fast(name))
 305                 return 1;
 306
 307         snprintf(strport, sizeof strport, "%u", default_ssh_port());
 308         memset(&hints, 0, sizeof(hints));
 309         hints.ai_family = options.address_family == -1 ?
 310             AF_UNSPEC : options.address_family;
 311         hints.ai_socktype = SOCK_STREAM;
 312         hints.ai_flags = AI_NUMERICHOST|AI_NUMERICSERV;
 313         if (getaddrinfo(name, strport, &hints, &res) != 0)
 314                 return 0;
 315         if (res == NULL || res->ai_next != NULL) {
 316                 freeaddrinfo(res);
 317                 return 0;
 318         }
 319         freeaddrinfo(res);
 320         return 1;
 321 }
 322
 323 /*
 324  * Attempt to resolve a numeric host address / port to a single address.
 325  * Returns a canonical address string.
 326  * Returns NULL on failure.
 327  * NB. this function must operate with a options having undefined members.
 328  */
 329 static struct addrinfo *
 330 resolve_addr(const char *name, int port, char *caddr, size_t clen)
 331 {
 332         char addr[NI_MAXHOST], strport[NI_MAXSERV];
 333         struct addrinfo hints, *res;
 334         int gaierr;
 335
 336         if (port <= 0)
 337                 port = default_ssh_port();
 338         snprintf(strport, sizeof strport, "%u", port);
 339         memset(&hints, 0, sizeof(hints));
 340         hints.ai_family = options.address_family == -1 ?
 341             AF_UNSPEC : options.address_family;
 342         hints.ai_socktype = SOCK_STREAM;
 343         hints.ai_flags = AI_NUMERICHOST|AI_NUMERICSERV;
 344         if ((gaierr = getaddrinfo(name, strport, &hints, &res)) != 0) {
 345                 debug2_f("could not resolve name %.100s as address: %s",
 346                     name, ssh_gai_strerror(gaierr));
 347                 return NULL;
 348         }
 349         if (res == NULL) {
 350                 debug_f("getaddrinfo %.100s returned no addresses", name);
 351                 return NULL;
 352         }
 353         if (res->ai_next != NULL) {
 354                 debug_f("getaddrinfo %.100s returned multiple addresses", name);
 355                 goto fail;
 356         }
 357         if ((gaierr = getnameinfo(res->ai_addr, res->ai_addrlen,
 358             addr, sizeof(addr), NULL, 0, NI_NUMERICHOST)) != 0) {
 359                 debug_f("Could not format address for name %.100s: %s",
 360                     name, ssh_gai_strerror(gaierr));
 361                 goto fail;
 362         }
 363         if (strlcpy(caddr, addr, clen) >= clen) {
 364                 error_f("host \"%s\" addr \"%s\" too long (max %lu)",
 365                     name,  addr, (u_long)clen);
 366                 if (clen > 0)
 367                         *caddr = '\0';
 368  fail:
 369                 freeaddrinfo(res);
 370                 return NULL;
 371         }
 372         return res;
 373 }
 374
 375 /*
 376  * Check whether the cname is a permitted replacement for the hostname
 377  * and perform the replacement if it is.
 378  * NB. this function must operate with a options having undefined members.
 379  */
 380 static int
 381 check_follow_cname(int direct, char **namep, const char *cname)
 382 {
 383         int i;
 384         struct allowed_cname *rule;
 385
 386         if (*cname == '\0' || !config_has_permitted_cnames(&options) ||
 387             strcmp(*namep, cname) == 0)
 388                 return 0;
 389         if (options.canonicalize_hostname == SSH_CANONICALISE_NO)
 390                 return 0;
 391         /*
 392          * Don't attempt to canonicalize names that will be interpreted by
 393          * a proxy or jump host unless the user specifically requests so.
 394          */
 395         if (!direct &&
 396             options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS)
 397                 return 0;
 398         debug3_f("check \"%s\" CNAME \"%s\"", *namep, cname);
 399         for (i = 0; i < options.num_permitted_cnames; i++) {
 400                 rule = options.permitted_cnames + i;
 401                 if (match_pattern_list(*namep, rule->source_list, 1) != 1 ||
 402                     match_pattern_list(cname, rule->target_list, 1) != 1)
 403                         continue;
 404                 verbose("Canonicalized DNS aliased hostname "
 405                     "\"%s\" => \"%s\"", *namep, cname);
 406                 free(*namep);
 407                 *namep = xstrdup(cname);
 408                 return 1;
 409         }
 410         return 0;
 411 }
 412
 413 /*
 414  * Attempt to resolve the supplied hostname after applying the user's
 415  * canonicalization rules. Returns the address list for the host or NULL
 416  * if no name was found after canonicalization.
 417  * NB. this function must operate with a options having undefined members.
 418  */
 419 static struct addrinfo *
 420 resolve_canonicalize(char **hostp, int port)
 421 {
 422         int i, direct, ndots;
 423         char *cp, *fullhost, newname[NI_MAXHOST];
 424         struct addrinfo *addrs;
 425
 426         /*
 427          * Attempt to canonicalise addresses, regardless of
 428          * whether hostname canonicalisation was requested
 429          */
 430         if ((addrs = resolve_addr(*hostp, port,
 431             newname, sizeof(newname))) != NULL) {
 432                 debug2_f("hostname %.100s is address", *hostp);
 433                 if (strcasecmp(*hostp, newname) != 0) {
 434                         debug2_f("canonicalised address \"%s\" => \"%s\"",
 435                             *hostp, newname);
 436                         free(*hostp);
 437                         *hostp = xstrdup(newname);
 438                 }
 439                 return addrs;
 440         }
 441
 442         /*
 443          * If this looks like an address but didn't parse as one, it might
 444          * be an address with an invalid interface scope. Skip further
 445          * attempts at canonicalisation.
 446          */
 447         if (is_addr_fast(*hostp)) {
 448                 debug_f("hostname %.100s is an unrecognised address", *hostp);
 449                 return NULL;
 450         }
 451
 452         if (options.canonicalize_hostname == SSH_CANONICALISE_NO)
 453                 return NULL;
 454
 455         /*
 456          * Don't attempt to canonicalize names that will be interpreted by
 457          * a proxy unless the user specifically requests so.
 458          */
 459         direct = option_clear_or_none(options.proxy_command) &&
 460             options.jump_host == NULL;
 461         if (!direct &&
 462             options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS)
 463                 return NULL;
 464
 465         /* If domain name is anchored, then resolve it now */
 466         if ((*hostp)[strlen(*hostp) - 1] == '.') {
 467                 debug3_f("name is fully qualified");
 468                 fullhost = xstrdup(*hostp);
 469                 if ((addrs = resolve_host(fullhost, port, 0,
 470                     newname, sizeof(newname))) != NULL)
 471                         goto found;
 472                 free(fullhost);
 473                 goto notfound;
 474         }
 475
 476         /* Don't apply canonicalization to sufficiently-qualified hostnames */
 477         ndots = 0;
 478         for (cp = *hostp; *cp != '\0'; cp++) {
 479                 if (*cp == '.')
 480                         ndots++;
 481         }
 482         if (ndots > options.canonicalize_max_dots) {
 483                 debug3_f("not canonicalizing hostname \"%s\" (max dots %d)",
 484                     *hostp, options.canonicalize_max_dots);
 485                 return NULL;
 486         }
 487         /* Attempt each supplied suffix */
 488         for (i = 0; i < options.num_canonical_domains; i++) {
 489                 if (strcasecmp(options.canonical_domains[i], "none") == 0)
 490                         break;
 491                 xasprintf(&fullhost, "%s.%s.", *hostp,
 492                     options.canonical_domains[i]);
 493                 debug3_f("attempting \"%s\" => \"%s\"", *hostp, fullhost);
 494                 if ((addrs = resolve_host(fullhost, port, 0,
 495                     newname, sizeof(newname))) == NULL) {
 496                         free(fullhost);
 497                         continue;
 498                 }
 499  found:
 500                 /* Remove trailing '.' */
 501                 fullhost[strlen(fullhost) - 1] = '\0';
 502                 /* Follow CNAME if requested */
 503                 if (!check_follow_cname(direct, &fullhost, newname)) {
 504                         debug("Canonicalized hostname \"%s\" => \"%s\"",
 505                             *hostp, fullhost);
 506                 }
 507                 free(*hostp);
 508                 *hostp = fullhost;
 509                 return addrs;
 510         }
 511  notfound:
 512         if (!options.canonicalize_fallback_local)
 513                 fatal("%s: Could not resolve host \"%s\"", __progname, *hostp);
 514         debug2_f("host %s not found in any suffix", *hostp);
 515         return NULL;
 516 }
 517
 518 /*
 519  * Check the result of hostkey loading, ignoring some errors and
 520  * fatal()ing for others.
 521  */
 522 static void
 523 check_load(int r, const char *path, const char *message)
 524 {
 525         switch (r) {
 526         case 0:
 527                 break;
 528         case SSH_ERR_INTERNAL_ERROR:
 529         case SSH_ERR_ALLOC_FAIL:
 530                 fatal_r(r, "load %s \"%s\"", message, path);
 531         case SSH_ERR_SYSTEM_ERROR:
 532                 /* Ignore missing files */
 533                 if (errno == ENOENT)
 534                         break;
 535                 /* FALLTHROUGH */
 536         default:
 537                 error_r(r, "load %s \"%s\"", message, path);
 538                 break;
 539         }
 540 }
 541
 542 /*
 543  * Read per-user configuration file.  Ignore the system wide config
 544  * file if the user specifies a config file on the command line.
 545  */
 546 static void
 547 process_config_files(const char *host_name, struct passwd *pw, int final_pass,
 548     int *want_final_pass)
 549 {
 550         char buf[PATH_MAX];
 551         int r;
 552
 553         if (config != NULL) {
 554                 if (strcasecmp(config, "none") != 0 &&
 555                     !read_config_file(config, pw, host, host_name, &options,
 556                     SSHCONF_USERCONF | (final_pass ? SSHCONF_FINAL : 0),
 557                     want_final_pass))
 558                         fatal("Can't open user config file %.100s: "
 559                             "%.100s", config, strerror(errno));
 560         } else {
 561                 r = snprintf(buf, sizeof buf, "%s/%s", pw->pw_dir,
 562                     _PATH_SSH_USER_CONFFILE);
 563                 if (r > 0 && (size_t)r < sizeof(buf))
 564                         (void)read_config_file(buf, pw, host, host_name,
 565                             &options, SSHCONF_CHECKPERM | SSHCONF_USERCONF |
 566                             (final_pass ? SSHCONF_FINAL : 0), want_final_pass);
 567
 568                 /* Read systemwide configuration file after user config. */
 569                 (void)read_config_file(_PATH_HOST_CONFIG_FILE, pw,
 570                     host, host_name, &options,
 571                     final_pass ? SSHCONF_FINAL : 0, want_final_pass);
 572         }
 573 }
 574
 575 /* Rewrite the port number in an addrinfo list of addresses */
 576 static void
 577 set_addrinfo_port(struct addrinfo *addrs, int port)
 578 {
 579         struct addrinfo *addr;
 580
 581         for (addr = addrs; addr != NULL; addr = addr->ai_next) {
 582                 switch (addr->ai_family) {
 583                 case AF_INET:
 584                         ((struct sockaddr_in *)addr->ai_addr)->
 585                             sin_port = htons(port);
 586                         break;
 587                 case AF_INET6:
 588                         ((struct sockaddr_in6 *)addr->ai_addr)->
 589                             sin6_port = htons(port);
 590                         break;
 591                 }
 592         }
 593 }
 594
 595 static void
 596 ssh_conn_info_free(struct ssh_conn_info *cinfo)
 597 {
 598         if (cinfo == NULL)
 599                 return;
 600         free(cinfo->conn_hash_hex);
 601         free(cinfo->shorthost);
 602         free(cinfo->uidstr);
 603         free(cinfo->keyalias);
 604         free(cinfo->thishost);
 605         free(cinfo->host_arg);
 606         free(cinfo->portstr);
 607         free(cinfo->remhost);
 608         free(cinfo->remuser);
 609         free(cinfo->homedir);
 610         free(cinfo->locuser);
 611         free(cinfo);
 612 }
 613
 614 /*
 615  * Main program for the ssh client.
 616  */
 617 int
 618 main(int ac, char **av)
 619 {
 620         struct ssh *ssh = NULL;
 621         int i, r, opt, exit_status, use_syslog, direct, timeout_ms;
 622         int was_addr, config_test = 0, opt_terminated = 0, want_final_pass = 0;
 623         char *p, *cp, *line, *argv0, *logfile, *host_arg;
 624         char cname[NI_MAXHOST], thishost[NI_MAXHOST];
 625         struct stat st;
 626         struct passwd *pw;
 627         extern int optind, optreset;
 628         extern char *optarg;
 629         struct Forward fwd;
 630         struct addrinfo *addrs = NULL;
 631         size_t n, len;
 632         u_int j;
 633         struct ssh_conn_info *cinfo = NULL;
 634
 635         /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
 636         sanitise_stdfd();
 637
 638         /*
 639          * Discard other fds that are hanging around. These can cause problem
 640          * with backgrounded ssh processes started by ControlPersist.
 641          */
 642         closefrom(STDERR_FILENO + 1);
 643
 644         __progname = ssh_get_progname(av[0]);
 645
 646 #ifndef HAVE_SETPROCTITLE
 647         /* Prepare for later setproctitle emulation */
 648         /* Save argv so it isn't clobbered by setproctitle() emulation */
 649         saved_av = xcalloc(ac + 1, sizeof(*saved_av));
 650         for (i = 0; i < ac; i++)
 651                 saved_av[i] = xstrdup(av[i]);
 652         saved_av[i] = NULL;
 653         compat_init_setproctitle(ac, av);
 654         av = saved_av;
 655 #endif
 656
 657         seed_rng();
 658
 659         /* Get user data. */
 660         pw = getpwuid(getuid());
 661         if (!pw) {
 662                 logit("No user exists for uid %lu", (u_long)getuid());
 663                 exit(255);
 664         }
 665         /* Take a copy of the returned structure. */
 666         pw = pwcopy(pw);
 667
 668         /*
 669          * Set our umask to something reasonable, as some files are created
 670          * with the default umask.  This will make them world-readable but
 671          * writable only by the owner, which is ok for all files for which we
 672          * don't set the modes explicitly.
 673          */
 674         umask(022);
 675
 676         msetlocale();
 677
 678         /*
 679          * Initialize option structure to indicate that no values have been
 680          * set.
 681          */
 682         initialize_options(&options);
 683
 684         /*
 685          * Prepare main ssh transport/connection structures
 686          */
 687         if ((ssh = ssh_alloc_session_state()) == NULL)
 688                 fatal("Couldn't allocate session state");
 689         channel_init_channels(ssh);
 690
 691         /* Parse command-line arguments. */
 692         host = NULL;
 693         use_syslog = 0;
 694         logfile = NULL;
 695         argv0 = av[0];
 696
 697  again:
 698         while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx"
 699             "AB:CD:E:F:GI:J:KL:MNO:PQ:R:S:TVw:W:XYy")) != -1) {
 700                 switch (opt) {
 701                 case '1':
 702                         fatal("SSH protocol v.1 is no longer supported");
 703                         break;
 704                 case '2':
 705                         /* Ignored */
 706                         break;
 707                 case '4':
 708                         options.address_family = AF_INET;
 709                         break;
 710                 case '6':
 711                         options.address_family = AF_INET6;
 712                         break;
 713                 case 'n':
 714                         options.stdin_null = 1;
 715                         break;
 716                 case 'f':
 717                         options.fork_after_authentication = 1;
 718                         options.stdin_null = 1;
 719                         break;
 720                 case 'x':
 721                         options.forward_x11 = 0;
 722                         break;
 723                 case 'X':
 724                         options.forward_x11 = 1;
 725                         break;
 726                 case 'y':
 727                         use_syslog = 1;
 728                         break;
 729                 case 'E':
 730                         logfile = optarg;
 731                         break;
 732                 case 'G':
 733                         config_test = 1;
 734                         break;
 735                 case 'Y':
 736                         options.forward_x11 = 1;
 737                         options.forward_x11_trusted = 1;
 738                         break;
 739                 case 'g':
 740                         options.fwd_opts.gateway_ports = 1;
 741                         break;
 742                 case 'O':
 743                         if (options.stdio_forward_host != NULL)
 744                                 fatal("Cannot specify multiplexing "
 745                                     "command with -W");
 746                         else if (muxclient_command != 0)
 747                                 fatal("Multiplexing command already specified");
 748                         if (strcmp(optarg, "check") == 0)
 749                                 muxclient_command = SSHMUX_COMMAND_ALIVE_CHECK;
 750                         else if (strcmp(optarg, "forward") == 0)
 751                                 muxclient_command = SSHMUX_COMMAND_FORWARD;
 752                         else if (strcmp(optarg, "exit") == 0)
 753                                 muxclient_command = SSHMUX_COMMAND_TERMINATE;
 754                         else if (strcmp(optarg, "stop") == 0)
 755                                 muxclient_command = SSHMUX_COMMAND_STOP;
 756                         else if (strcmp(optarg, "cancel") == 0)
 757                                 muxclient_command = SSHMUX_COMMAND_CANCEL_FWD;
 758                         else if (strcmp(optarg, "proxy") == 0)
 759                                 muxclient_command = SSHMUX_COMMAND_PROXY;
 760                         else
 761                                 fatal("Invalid multiplex command.");
 762                         break;
 763                 case 'P':       /* deprecated */
 764                         break;
 765                 case 'Q':
 766                         cp = NULL;
 767                         if (strcmp(optarg, "cipher") == 0 ||
 768                             strcasecmp(optarg, "Ciphers") == 0)
 769                                 cp = cipher_alg_list('\n', 0);
 770                         else if (strcmp(optarg, "cipher-auth") == 0)
 771                                 cp = cipher_alg_list('\n', 1);
 772                         else if (strcmp(optarg, "mac") == 0 ||
 773                             strcasecmp(optarg, "MACs") == 0)
 774                                 cp = mac_alg_list('\n');
 775                         else if (strcmp(optarg, "kex") == 0 ||
 776                             strcasecmp(optarg, "KexAlgorithms") == 0)
 777                                 cp = kex_alg_list('\n');
 778                         else if (strcmp(optarg, "key") == 0)
 779                                 cp = sshkey_alg_list(0, 0, 0, '\n');
 780                         else if (strcmp(optarg, "key-cert") == 0)
 781                                 cp = sshkey_alg_list(1, 0, 0, '\n');
 782                         else if (strcmp(optarg, "key-plain") == 0)
 783                                 cp = sshkey_alg_list(0, 1, 0, '\n');
 784                         else if (strcmp(optarg, "key-sig") == 0 ||
 785                             strcasecmp(optarg, "PubkeyAcceptedKeyTypes") == 0 || /* deprecated name */
 786                             strcasecmp(optarg, "PubkeyAcceptedAlgorithms") == 0 ||
 787                             strcasecmp(optarg, "HostKeyAlgorithms") == 0 ||
 788                             strcasecmp(optarg, "HostbasedKeyTypes") == 0 || /* deprecated name */
 789                             strcasecmp(optarg, "HostbasedAcceptedKeyTypes") == 0 || /* deprecated name */
 790                             strcasecmp(optarg, "HostbasedAcceptedAlgorithms") == 0)
 791                                 cp = sshkey_alg_list(0, 0, 1, '\n');
 792                         else if (strcmp(optarg, "sig") == 0)
 793                                 cp = sshkey_alg_list(0, 1, 1, '\n');
 794                         else if (strcmp(optarg, "protocol-version") == 0)
 795                                 cp = xstrdup("2");
 796                         else if (strcmp(optarg, "compression") == 0) {
 797                                 cp = xstrdup(compression_alg_list(0));
 798                                 len = strlen(cp);
 799                                 for (n = 0; n < len; n++)
 800                                         if (cp[n] == ',')
 801                                                 cp[n] = '\n';
 802                         } else if (strcmp(optarg, "help") == 0) {
 803                                 cp = xstrdup(
 804                                     "cipher\ncipher-auth\ncompression\nkex\n"
 805                                     "key\nkey-cert\nkey-plain\nkey-sig\nmac\n"
 806                                     "protocol-version\nsig");
 807                         }
 808                         if (cp == NULL)
 809                                 fatal("Unsupported query \"%s\"", optarg);
 810                         printf("%s\n", cp);
 811                         free(cp);
 812                         exit(0);
 813                         break;
 814                 case 'a':
 815                         options.forward_agent = 0;
 816                         break;
 817                 case 'A':
 818                         options.forward_agent = 1;
 819                         break;
 820                 case 'k':
 821                         options.gss_deleg_creds = 0;
 822                         break;
 823                 case 'K':
 824                         options.gss_authentication = 1;
 825                         options.gss_deleg_creds = 1;
 826                         break;
 827                 case 'i':
 828                         p = tilde_expand_filename(optarg, getuid());
 829                         if (stat(p, &st) == -1)
 830                                 fprintf(stderr, "Warning: Identity file %s "
 831                                     "not accessible: %s.\n", p,
 832                                     strerror(errno));
 833                         else
 834                                 add_identity_file(&options, NULL, p, 1);
 835                         free(p);
 836                         break;
 837                 case 'I':
 838 #ifdef ENABLE_PKCS11
 839                         free(options.pkcs11_provider);
 840                         options.pkcs11_provider = xstrdup(optarg);
 841 #else
 842                         fprintf(stderr, "no support for PKCS#11.\n");
 843 #endif
 844                         break;
 845                 case 'J':
 846                         if (options.jump_host != NULL) {
 847                                 fatal("Only a single -J option is permitted "
 848                                     "(use commas to separate multiple "
 849                                     "jump hops)");
 850                         }
 851                         if (options.proxy_command != NULL)
 852                                 fatal("Cannot specify -J with ProxyCommand");
 853                         if (parse_jump(optarg, &options, 1) == -1)
 854                                 fatal("Invalid -J argument");
 855                         options.proxy_command = xstrdup("none");
 856                         break;
 857                 case 't':
 858                         if (options.request_tty == REQUEST_TTY_YES)
 859                                 options.request_tty = REQUEST_TTY_FORCE;
 860                         else
 861                                 options.request_tty = REQUEST_TTY_YES;
 862                         break;
 863                 case 'v':
 864                         if (debug_flag == 0) {
 865                                 debug_flag = 1;
 866                                 options.log_level = SYSLOG_LEVEL_DEBUG1;
 867                         } else {
 868                                 if (options.log_level < SYSLOG_LEVEL_DEBUG3) {
 869                                         debug_flag++;
 870                                         options.log_level++;
 871                                 }
 872                         }
 873                         break;
 874                 case 'V':
 875                         fprintf(stderr, "%s, %s\n",
 876                             SSH_RELEASE, SSH_OPENSSL_VERSION);
 877                         if (opt == 'V')
 878                                 exit(0);
 879                         break;
 880                 case 'w':
 881                         if (options.tun_open == -1)
 882                                 options.tun_open = SSH_TUNMODE_DEFAULT;
 883                         options.tun_local = a2tun(optarg, &options.tun_remote);
 884                         if (options.tun_local == SSH_TUNID_ERR) {
 885                                 fprintf(stderr,
 886                                     "Bad tun device '%s'\n", optarg);
 887                                 exit(255);
 888                         }
 889                         break;
 890                 case 'W':
 891                         if (options.stdio_forward_host != NULL)
 892                                 fatal("stdio forward already specified");
 893                         if (muxclient_command != 0)
 894                                 fatal("Cannot specify stdio forward with -O");
 895                         if (parse_forward(&fwd, optarg, 1, 0)) {
 896                                 options.stdio_forward_host = fwd.listen_host;
 897                                 options.stdio_forward_port = fwd.listen_port;
 898                                 free(fwd.connect_host);
 899                         } else {
 900                                 fprintf(stderr,
 901                                     "Bad stdio forwarding specification '%s'\n",
 902                                     optarg);
 903                                 exit(255);
 904                         }
 905                         options.request_tty = REQUEST_TTY_NO;
 906                         options.session_type = SESSION_TYPE_NONE;
 907                         break;
 908                 case 'q':
 909                         options.log_level = SYSLOG_LEVEL_QUIET;
 910                         break;
 911                 case 'e':
 912                         if (optarg[0] == '^' && optarg[2] == 0 &&
 913                             (u_char) optarg[1] >= 64 &&
 914                             (u_char) optarg[1] < 128)
 915                                 options.escape_char = (u_char) optarg[1] & 31;
 916                         else if (strlen(optarg) == 1)
 917                                 options.escape_char = (u_char) optarg[0];
 918                         else if (strcmp(optarg, "none") == 0)
 919                                 options.escape_char = SSH_ESCAPECHAR_NONE;
 920                         else {
 921                                 fprintf(stderr, "Bad escape character '%s'.\n",
 922                                     optarg);
 923                                 exit(255);
 924                         }
 925                         break;
 926                 case 'c':
 927                         if (!ciphers_valid(*optarg == '+' || *optarg == '^' ?
 928                             optarg + 1 : optarg)) {
 929                                 fprintf(stderr, "Unknown cipher type '%s'\n",
 930                                     optarg);
 931                                 exit(255);
 932                         }
 933                         free(options.ciphers);
 934                         options.ciphers = xstrdup(optarg);
 935                         break;
 936                 case 'm':
 937                         if (mac_valid(optarg)) {
 938                                 free(options.macs);
 939                                 options.macs = xstrdup(optarg);
 940                         } else {
 941                                 fprintf(stderr, "Unknown mac type '%s'\n",
 942                                     optarg);
 943                                 exit(255);
 944                         }
 945                         break;
 946                 case 'M':
 947                         if (options.control_master == SSHCTL_MASTER_YES)
 948                                 options.control_master = SSHCTL_MASTER_ASK;
 949                         else
 950                                 options.control_master = SSHCTL_MASTER_YES;
 951                         break;
 952                 case 'p':
 953                         if (options.port == -1) {
 954                                 options.port = a2port(optarg);
 955                                 if (options.port <= 0) {
 956                                         fprintf(stderr, "Bad port '%s'\n",
 957                                             optarg);
 958                                         exit(255);
 959                                 }
 960                         }
 961                         break;
 962                 case 'l':
 963                         if (options.user == NULL)
 964                                 options.user = optarg;
 965                         break;
 966
 967                 case 'L':
 968                         if (parse_forward(&fwd, optarg, 0, 0))
 969                                 add_local_forward(&options, &fwd);
 970                         else {
 971                                 fprintf(stderr,
 972                                     "Bad local forwarding specification '%s'\n",
 973                                     optarg);
 974                                 exit(255);
 975                         }
 976                         break;
 977
 978                 case 'R':
 979                         if (parse_forward(&fwd, optarg, 0, 1) ||
 980                             parse_forward(&fwd, optarg, 1, 1)) {
 981                                 add_remote_forward(&options, &fwd);
 982                         } else {
 983                                 fprintf(stderr,
 984                                     "Bad remote forwarding specification "
 985                                     "'%s'\n", optarg);
 986                                 exit(255);
 987                         }
 988                         break;
 989
 990                 case 'D':
 991                         if (parse_forward(&fwd, optarg, 1, 0)) {
 992                                 add_local_forward(&options, &fwd);
 993                         } else {
 994                                 fprintf(stderr,
 995                                     "Bad dynamic forwarding specification "
 996                                     "'%s'\n", optarg);
 997                                 exit(255);
 998                         }
 999                         break;
1000
1001                 case 'C':
1002 #ifdef WITH_ZLIB
1003                         options.compression = 1;
1004 #else
1005                         error("Compression not supported, disabling.");
1006 #endif
1007                         break;
1008                 case 'N':
1009                         if (options.session_type != -1 &&
1010                             options.session_type != SESSION_TYPE_NONE)
1011                                 fatal("Cannot specify -N with -s/SessionType");
1012                         options.session_type = SESSION_TYPE_NONE;
1013                         options.request_tty = REQUEST_TTY_NO;
1014                         break;
1015                 case 'T':
1016                         options.request_tty = REQUEST_TTY_NO;
1017                         break;
1018                 case 'o':
1019                         line = xstrdup(optarg);
1020                         if (process_config_line(&options, pw,
1021                             host ? host : "", host ? host : "", line,
1022                             "command-line", 0, NULL, SSHCONF_USERCONF) != 0)
1023                                 exit(255);
1024                         free(line);
1025                         break;
1026                 case 's':
1027                         if (options.session_type != -1 &&
1028                             options.session_type != SESSION_TYPE_SUBSYSTEM)
1029                                 fatal("Cannot specify -s with -N/SessionType");
1030                         options.session_type = SESSION_TYPE_SUBSYSTEM;
1031                         break;
1032                 case 'S':
1033                         free(options.control_path);
1034                         options.control_path = xstrdup(optarg);
1035                         break;
1036                 case 'b':
1037                         options.bind_address = optarg;
1038                         break;
1039                 case 'B':
1040                         options.bind_interface = optarg;
1041                         break;
1042                 case 'F':
1043                         config = optarg;
1044                         break;
1045                 default:
1046                         usage();
1047                 }
1048         }
1049
1050         if (optind > 1 && strcmp(av[optind - 1], "--") == 0)
1051                 opt_terminated = 1;
1052
1053         ac -= optind;
1054         av += optind;
1055
1056         if (ac > 0 && !host) {
1057                 int tport;
1058                 char *tuser;
1059                 switch (parse_ssh_uri(*av, &tuser, &host, &tport)) {
1060                 case -1:
1061                         usage();
1062                         break;
1063                 case 0:
1064                         if (options.user == NULL) {
1065                                 options.user = tuser;
1066                                 tuser = NULL;
1067                         }
1068                         free(tuser);
1069                         if (options.port == -1 && tport != -1)
1070                                 options.port = tport;
1071                         break;
1072                 default:
1073                         p = xstrdup(*av);
1074                         cp = strrchr(p, '@');
1075                         if (cp != NULL) {
1076                                 if (cp == p)
1077                                         usage();
1078                                 if (options.user == NULL) {
1079                                         options.user = p;
1080                                         p = NULL;
1081                                 }
1082                                 *cp++ = '\0';
1083                                 host = xstrdup(cp);
1084                                 free(p);
1085                         } else
1086                                 host = p;
1087                         break;
1088                 }
1089                 if (ac > 1 && !opt_terminated) {
1090                         optind = optreset = 1;
1091                         goto again;
1092                 }
1093                 ac--, av++;
1094         }
1095
1096         /* Check that we got a host name. */
1097         if (!host)
1098                 usage();
1099
1100         host_arg = xstrdup(host);
1101
1102         /* Initialize the command to execute on remote host. */
1103         if ((command = sshbuf_new()) == NULL)
1104                 fatal("sshbuf_new failed");
1105
1106         /*
1107          * Save the command to execute on the remote host in a buffer. There
1108          * is no limit on the length of the command, except by the maximum
1109          * packet size.  Also sets the tty flag if there is no command.
1110          */
1111         if (!ac) {
1112                 /* No command specified - execute shell on a tty. */
1113                 if (options.session_type == SESSION_TYPE_SUBSYSTEM) {
1114                         fprintf(stderr,
1115                             "You must specify a subsystem to invoke.\n");
1116                         usage();
1117                 }
1118         } else {
1119                 /* A command has been specified.  Store it into the buffer. */
1120                 for (i = 0; i < ac; i++) {
1121                         if ((r = sshbuf_putf(command, "%s%s",
1122                             i ? " " : "", av[i])) != 0)
1123                                 fatal_fr(r, "buffer error");
1124                 }
1125         }
1126
1127         /*
1128          * Initialize "log" output.  Since we are the client all output
1129          * goes to stderr unless otherwise specified by -y or -E.
1130          */
1131         if (use_syslog && logfile != NULL)
1132                 fatal("Can't specify both -y and -E");
1133         if (logfile != NULL)
1134                 log_redirect_stderr_to(logfile);
1135         log_init(argv0,
1136             options.log_level == SYSLOG_LEVEL_NOT_SET ?
1137             SYSLOG_LEVEL_INFO : options.log_level,
1138             options.log_facility == SYSLOG_FACILITY_NOT_SET ?
1139             SYSLOG_FACILITY_USER : options.log_facility,
1140             !use_syslog);
1141
1142         if (debug_flag)
1143                 logit("%s, %s", SSH_RELEASE, SSH_OPENSSL_VERSION);
1144
1145         /* Parse the configuration files */
1146         process_config_files(host_arg, pw, 0, &want_final_pass);
1147         if (want_final_pass)
1148                 debug("configuration requests final Match pass");
1149
1150         /* Hostname canonicalisation needs a few options filled. */
1151         fill_default_options_for_canonicalization(&options);
1152
1153         /* If the user has replaced the hostname then take it into use now */
1154         if (options.hostname != NULL) {
1155                 /* NB. Please keep in sync with readconf.c:match_cfg_line() */
1156                 cp = percent_expand(options.hostname,
1157                     "h", host, (char *)NULL);
1158                 free(host);
1159                 host = cp;
1160                 free(options.hostname);
1161                 options.hostname = xstrdup(host);
1162         }
1163
1164         /* Don't lowercase addresses, they will be explicitly canonicalised */
1165         if ((was_addr = is_addr(host)) == 0)
1166                 lowercase(host);
1167
1168         /*
1169          * Try to canonicalize if requested by configuration or the
1170          * hostname is an address.
1171          */
1172         if (options.canonicalize_hostname != SSH_CANONICALISE_NO || was_addr)
1173                 addrs = resolve_canonicalize(&host, options.port);
1174
1175         /*
1176          * If CanonicalizePermittedCNAMEs have been specified but
1177          * other canonicalization did not happen (by not being requested
1178          * or by failing with fallback) then the hostname may still be changed
1179          * as a result of CNAME following.
1180          *
1181          * Try to resolve the bare hostname name using the system resolver's
1182          * usual search rules and then apply the CNAME follow rules.
1183          *
1184          * Skip the lookup if a ProxyCommand is being used unless the user
1185          * has specifically requested canonicalisation for this case via
1186          * CanonicalizeHostname=always
1187          */
1188         direct = option_clear_or_none(options.proxy_command) &&
1189             options.jump_host == NULL;
1190         if (addrs == NULL && config_has_permitted_cnames(&options) && (direct ||
1191             options.canonicalize_hostname == SSH_CANONICALISE_ALWAYS)) {
1192                 if ((addrs = resolve_host(host, options.port,
1193                     direct, cname, sizeof(cname))) == NULL) {
1194                         /* Don't fatal proxied host names not in the DNS */
1195                         if (direct)
1196                                 cleanup_exit(255); /* logged in resolve_host */
1197                 } else
1198                         check_follow_cname(direct, &host, cname);
1199         }
1200
1201         /*
1202          * If canonicalisation is enabled then re-parse the configuration
1203          * files as new stanzas may match.
1204          */
1205         if (options.canonicalize_hostname != 0 && !want_final_pass) {
1206                 debug("hostname canonicalisation enabled, "
1207                     "will re-parse configuration");
1208                 want_final_pass = 1;
1209         }
1210
1211         if (want_final_pass) {
1212                 debug("re-parsing configuration");
1213                 free(options.hostname);
1214                 options.hostname = xstrdup(host);
1215                 process_config_files(host_arg, pw, 1, NULL);
1216                 /*
1217                  * Address resolution happens early with canonicalisation
1218                  * enabled and the port number may have changed since, so
1219                  * reset it in address list
1220                  */
1221                 if (addrs != NULL && options.port > 0)
1222                         set_addrinfo_port(addrs, options.port);
1223         }
1224
1225         /* Fill configuration defaults. */
1226         if (fill_default_options(&options) != 0)
1227                 cleanup_exit(255);
1228
1229         if (options.user == NULL)
1230                 options.user = xstrdup(pw->pw_name);
1231
1232         /*
1233          * If ProxyJump option specified, then construct a ProxyCommand now.
1234          */
1235         if (options.jump_host != NULL) {
1236                 char port_s[8];
1237                 const char *jumpuser = options.jump_user, *sshbin = argv0;
1238                 int port = options.port, jumpport = options.jump_port;
1239
1240                 if (port <= 0)
1241                         port = default_ssh_port();
1242                 if (jumpport <= 0)
1243                         jumpport = default_ssh_port();
1244                 if (jumpuser == NULL)
1245                         jumpuser = options.user;
1246                 if (strcmp(options.jump_host, host) == 0 && port == jumpport &&
1247                     strcmp(options.user, jumpuser) == 0)
1248                         fatal("jumphost loop via %s", options.jump_host);
1249
1250                 /*
1251                  * Try to use SSH indicated by argv[0], but fall back to
1252                  * "ssh" if it appears unavailable.
1253                  */
1254                 if (strchr(argv0, '/') != NULL && access(argv0, X_OK) != 0)
1255                         sshbin = "ssh";
1256
1257                 /* Consistency check */
1258                 if (options.proxy_command != NULL)
1259                         fatal("inconsistent options: ProxyCommand+ProxyJump");
1260                 /* Never use FD passing for ProxyJump */
1261                 options.proxy_use_fdpass = 0;
1262                 snprintf(port_s, sizeof(port_s), "%d", options.jump_port);
1263                 xasprintf(&options.proxy_command,
1264                     "%s%s%s%s%s%s%s%s%s%s%.*s -W '[%%h]:%%p' %s",
1265                     sshbin,
1266                     /* Optional "-l user" argument if jump_user set */
1267                     options.jump_user == NULL ? "" : " -l ",
1268                     options.jump_user == NULL ? "" : options.jump_user,
1269                     /* Optional "-p port" argument if jump_port set */
1270                     options.jump_port <= 0 ? "" : " -p ",
1271                     options.jump_port <= 0 ? "" : port_s,
1272                     /* Optional additional jump hosts ",..." */
1273                     options.jump_extra == NULL ? "" : " -J ",
1274                     options.jump_extra == NULL ? "" : options.jump_extra,
1275                     /* Optional "-F" argumment if -F specified */
1276                     config == NULL ? "" : " -F ",
1277                     config == NULL ? "" : config,
1278                     /* Optional "-v" arguments if -v set */
1279                     debug_flag ? " -" : "",
1280                     debug_flag, "vvv",
1281                     /* Mandatory hostname */
1282                     options.jump_host);
1283                 debug("Setting implicit ProxyCommand from ProxyJump: %s",
1284                     options.proxy_command);
1285         }
1286
1287         if (options.port == 0)
1288                 options.port = default_ssh_port();
1289         channel_set_af(ssh, options.address_family);
1290
1291         /* Tidy and check options */
1292         if (options.host_key_alias != NULL)
1293                 lowercase(options.host_key_alias);
1294         if (options.proxy_command != NULL &&
1295             strcmp(options.proxy_command, "-") == 0 &&
1296             options.proxy_use_fdpass)
1297                 fatal("ProxyCommand=- and ProxyUseFDPass are incompatible");
1298         if (options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK) {
1299                 if (options.control_persist && options.control_path != NULL) {
1300                         debug("UpdateHostKeys=ask is incompatible with "
1301                             "ControlPersist; disabling");
1302                         options.update_hostkeys = 0;
1303                 } else if (sshbuf_len(command) != 0 ||
1304                     options.remote_command != NULL ||
1305                     options.request_tty == REQUEST_TTY_NO) {
1306                         debug("UpdateHostKeys=ask is incompatible with "
1307                             "remote command execution; disabling");
1308                         options.update_hostkeys = 0;
1309                 } else if (options.log_level < SYSLOG_LEVEL_INFO) {
1310                         /* no point logging anything; user won't see it */
1311                         options.update_hostkeys = 0;
1312                 }
1313         }
1314         if (options.connection_attempts <= 0)
1315                 fatal("Invalid number of ConnectionAttempts");
1316
1317         if (sshbuf_len(command) != 0 && options.remote_command != NULL)
1318                 fatal("Cannot execute command-line and remote command.");
1319
1320         /* Cannot fork to background if no command. */
1321         if (options.fork_after_authentication && sshbuf_len(command) == 0 &&
1322             options.remote_command == NULL &&
1323             options.session_type != SESSION_TYPE_NONE)
1324                 fatal("Cannot fork into background without a command "
1325                     "to execute.");
1326
1327         /* reinit */
1328         log_init(argv0, options.log_level, options.log_facility, !use_syslog);
1329         for (j = 0; j < options.num_log_verbose; j++) {
1330                 if (strcasecmp(options.log_verbose[j], "none") == 0)
1331                         break;
1332                 log_verbose_add(options.log_verbose[j]);
1333         }
1334
1335         if (options.request_tty == REQUEST_TTY_YES ||
1336             options.request_tty == REQUEST_TTY_FORCE)
1337                 tty_flag = 1;
1338
1339         /* Allocate a tty by default if no command specified. */
1340         if (sshbuf_len(command) == 0 && options.remote_command == NULL)
1341                 tty_flag = options.request_tty != REQUEST_TTY_NO;
1342
1343         /* Force no tty */
1344         if (options.request_tty == REQUEST_TTY_NO ||
1345             (muxclient_command && muxclient_command != SSHMUX_COMMAND_PROXY))
1346                 tty_flag = 0;
1347         /* Do not allocate a tty if stdin is not a tty. */
1348         if ((!isatty(fileno(stdin)) || options.stdin_null) &&
1349             options.request_tty != REQUEST_TTY_FORCE) {
1350                 if (tty_flag)
1351                         logit("Pseudo-terminal will not be allocated because "
1352                             "stdin is not a terminal.");
1353                 tty_flag = 0;
1354         }
1355
1356         /* Set up strings used to percent_expand() arguments */
1357         cinfo = xcalloc(1, sizeof(*cinfo));
1358         if (gethostname(thishost, sizeof(thishost)) == -1)
1359                 fatal("gethostname: %s", strerror(errno));
1360         cinfo->thishost = xstrdup(thishost);
1361         thishost[strcspn(thishost, ".")] = '\0';
1362         cinfo->shorthost = xstrdup(thishost);
1363         xasprintf(&cinfo->portstr, "%d", options.port);
1364         xasprintf(&cinfo->uidstr, "%llu",
1365             (unsigned long long)pw->pw_uid);
1366         cinfo->keyalias = xstrdup(options.host_key_alias ?
1367             options.host_key_alias : host_arg);
1368         cinfo->conn_hash_hex = ssh_connection_hash(cinfo->thishost, host,
1369             cinfo->portstr, options.user);
1370         cinfo->host_arg = xstrdup(host_arg);
1371         cinfo->remhost = xstrdup(host);
1372         cinfo->remuser = xstrdup(options.user);
1373         cinfo->homedir = xstrdup(pw->pw_dir);
1374         cinfo->locuser = xstrdup(pw->pw_name);
1375
1376         /*
1377          * Expand tokens in arguments. NB. LocalCommand is expanded later,
1378          * after port-forwarding is set up, so it may pick up any local
1379          * tunnel interface name allocated.
1380          */
1381         if (options.remote_command != NULL) {
1382                 debug3("expanding RemoteCommand: %s", options.remote_command);
1383                 cp = options.remote_command;
1384                 options.remote_command = default_client_percent_expand(cp,
1385                     cinfo);
1386                 debug3("expanded RemoteCommand: %s", options.remote_command);
1387                 free(cp);
1388                 if ((r = sshbuf_put(command, options.remote_command,
1389                     strlen(options.remote_command))) != 0)
1390                         fatal_fr(r, "buffer error");
1391         }
1392
1393         if (options.control_path != NULL) {
1394                 cp = tilde_expand_filename(options.control_path, getuid());
1395                 free(options.control_path);
1396                 options.control_path = default_client_percent_dollar_expand(cp,
1397                     cinfo);
1398                 free(cp);
1399         }
1400
1401         if (options.identity_agent != NULL) {
1402                 p = tilde_expand_filename(options.identity_agent, getuid());
1403                 cp = default_client_percent_dollar_expand(p, cinfo);
1404                 free(p);
1405                 free(options.identity_agent);
1406                 options.identity_agent = cp;
1407         }
1408
1409         if (options.forward_agent_sock_path != NULL) {
1410                 p = tilde_expand_filename(options.forward_agent_sock_path,
1411                     getuid());
1412                 cp = default_client_percent_dollar_expand(p, cinfo);
1413                 free(p);
1414                 free(options.forward_agent_sock_path);
1415                 options.forward_agent_sock_path = cp;
1416                 if (stat(options.forward_agent_sock_path, &st) != 0) {
1417                         error("Cannot forward agent socket path \"%s\": %s",
1418                             options.forward_agent_sock_path, strerror(errno));
1419                         if (options.exit_on_forward_failure)
1420                                 cleanup_exit(255);
1421                 }
1422         }
1423
1424         if (options.num_system_hostfiles > 0 &&
1425             strcasecmp(options.system_hostfiles[0], "none") == 0) {
1426                 if (options.num_system_hostfiles > 1)
1427                         fatal("Invalid GlobalKnownHostsFiles: \"none\" "
1428                             "appears with other entries");
1429                 free(options.system_hostfiles[0]);
1430                 options.system_hostfiles[0] = NULL;
1431                 options.num_system_hostfiles = 0;
1432         }
1433
1434         if (options.num_user_hostfiles > 0 &&
1435             strcasecmp(options.user_hostfiles[0], "none") == 0) {
1436                 if (options.num_user_hostfiles > 1)
1437                         fatal("Invalid UserKnownHostsFiles: \"none\" "
1438                             "appears with other entries");
1439                 free(options.user_hostfiles[0]);
1440                 options.user_hostfiles[0] = NULL;
1441                 options.num_user_hostfiles = 0;
1442         }
1443         for (j = 0; j < options.num_user_hostfiles; j++) {
1444                 if (options.user_hostfiles[j] == NULL)
1445                         continue;
1446                 cp = tilde_expand_filename(options.user_hostfiles[j], getuid());
1447                 p = default_client_percent_dollar_expand(cp, cinfo);
1448                 if (strcmp(options.user_hostfiles[j], p) != 0)
1449                         debug3("expanded UserKnownHostsFile '%s' -> "
1450                             "'%s'", options.user_hostfiles[j], p);
1451                 free(options.user_hostfiles[j]);
1452                 free(cp);
1453                 options.user_hostfiles[j] = p;
1454         }
1455
1456         for (i = 0; i < options.num_local_forwards; i++) {
1457                 if (options.local_forwards[i].listen_path != NULL) {
1458                         cp = options.local_forwards[i].listen_path;
1459                         p = options.local_forwards[i].listen_path =
1460                             default_client_percent_expand(cp, cinfo);
1461                         if (strcmp(cp, p) != 0)
1462                                 debug3("expanded LocalForward listen path "
1463                                     "'%s' -> '%s'", cp, p);
1464                         free(cp);
1465                 }
1466                 if (options.local_forwards[i].connect_path != NULL) {
1467                         cp = options.local_forwards[i].connect_path;
1468                         p = options.local_forwards[i].connect_path =
1469                             default_client_percent_expand(cp, cinfo);
1470                         if (strcmp(cp, p) != 0)
1471                                 debug3("expanded LocalForward connect path "
1472                                     "'%s' -> '%s'", cp, p);
1473                         free(cp);
1474                 }
1475         }
1476
1477         for (i = 0; i < options.num_remote_forwards; i++) {
1478                 if (options.remote_forwards[i].listen_path != NULL) {
1479                         cp = options.remote_forwards[i].listen_path;
1480                         p = options.remote_forwards[i].listen_path =
1481                             default_client_percent_expand(cp, cinfo);
1482                         if (strcmp(cp, p) != 0)
1483                                 debug3("expanded RemoteForward listen path "
1484                                     "'%s' -> '%s'", cp, p);
1485                         free(cp);
1486                 }
1487                 if (options.remote_forwards[i].connect_path != NULL) {
1488                         cp = options.remote_forwards[i].connect_path;
1489                         p = options.remote_forwards[i].connect_path =
1490                             default_client_percent_expand(cp, cinfo);
1491                         if (strcmp(cp, p) != 0)
1492                                 debug3("expanded RemoteForward connect path "
1493                                     "'%s' -> '%s'", cp, p);
1494                         free(cp);
1495                 }
1496         }
1497
1498         if (config_test) {
1499                 dump_client_config(&options, host);
1500                 exit(0);
1501         }
1502
1503         /* Expand SecurityKeyProvider if it refers to an environment variable */
1504         if (options.sk_provider != NULL && *options.sk_provider == '$' &&
1505             strlen(options.sk_provider) > 1) {
1506                 if ((cp = getenv(options.sk_provider + 1)) == NULL) {
1507                         debug("Authenticator provider %s did not resolve; "
1508                             "disabling", options.sk_provider);
1509                         free(options.sk_provider);
1510                         options.sk_provider = NULL;
1511                 } else {
1512                         debug2("resolved SecurityKeyProvider %s => %s",
1513                             options.sk_provider, cp);
1514                         free(options.sk_provider);
1515                         options.sk_provider = xstrdup(cp);
1516                 }
1517         }
1518
1519         if (muxclient_command != 0 && options.control_path == NULL)
1520                 fatal("No ControlPath specified for \"-O\" command");
1521         if (options.control_path != NULL) {
1522                 int sock;
1523                 if ((sock = muxclient(options.control_path)) >= 0) {
1524                         ssh_packet_set_connection(ssh, sock, sock);
1525                         ssh_packet_set_mux(ssh);
1526                         goto skip_connect;
1527                 }
1528         }
1529
1530         /*
1531          * If hostname canonicalisation was not enabled, then we may not
1532          * have yet resolved the hostname. Do so now.
1533          */
1534         if (addrs == NULL && options.proxy_command == NULL) {
1535                 debug2("resolving \"%s\" port %d", host, options.port);
1536                 if ((addrs = resolve_host(host, options.port, 1,
1537                     cname, sizeof(cname))) == NULL)
1538                         cleanup_exit(255); /* resolve_host logs the error */
1539         }
1540
1541         if (options.connection_timeout >= INT_MAX/1000)
1542                 timeout_ms = INT_MAX;
1543         else
1544                 timeout_ms = options.connection_timeout * 1000;
1545
1546         /* Open a connection to the remote host. */
1547         if (ssh_connect(ssh, host, host_arg, addrs, &hostaddr, options.port,
1548             options.connection_attempts,
1549             &timeout_ms, options.tcp_keep_alive) != 0)
1550                 exit(255);
1551
1552         if (addrs != NULL)
1553                 freeaddrinfo(addrs);
1554
1555         ssh_packet_set_timeout(ssh, options.server_alive_interval,
1556             options.server_alive_count_max);
1557
1558         if (timeout_ms > 0)
1559                 debug3("timeout: %d ms remain after connect", timeout_ms);
1560
1561         /*
1562          * If we successfully made the connection and we have hostbased auth
1563          * enabled, load the public keys so we can later use the ssh-keysign
1564          * helper to sign challenges.
1565          */
1566         sensitive_data.nkeys = 0;
1567         sensitive_data.keys = NULL;
1568         if (options.hostbased_authentication) {
1569                 sensitive_data.nkeys = 10;
1570                 sensitive_data.keys = xcalloc(sensitive_data.nkeys,
1571                     sizeof(struct sshkey));
1572
1573                 /* XXX check errors? */
1574 #define L_PUBKEY(p,o) do { \
1575         if ((o) >= sensitive_data.nkeys) \
1576                 fatal_f("pubkey out of array bounds"); \
1577         check_load(sshkey_load_public(p, &(sensitive_data.keys[o]), NULL), \
1578             p, "pubkey"); \
1579 } while (0)
1580 #define L_CERT(p,o) do { \
1581         if ((o) >= sensitive_data.nkeys) \
1582                 fatal_f("cert out of array bounds"); \
1583         check_load(sshkey_load_cert(p, &(sensitive_data.keys[o])), p, "cert"); \
1584 } while (0)
1585
1586                 if (options.hostbased_authentication == 1) {
1587                         L_CERT(_PATH_HOST_ECDSA_KEY_FILE, 0);
1588                         L_CERT(_PATH_HOST_ED25519_KEY_FILE, 1);
1589                         L_CERT(_PATH_HOST_RSA_KEY_FILE, 2);
1590                         L_CERT(_PATH_HOST_DSA_KEY_FILE, 3);
1591                         L_PUBKEY(_PATH_HOST_ECDSA_KEY_FILE, 4);
1592                         L_PUBKEY(_PATH_HOST_ED25519_KEY_FILE, 5);
1593                         L_PUBKEY(_PATH_HOST_RSA_KEY_FILE, 6);
1594                         L_PUBKEY(_PATH_HOST_DSA_KEY_FILE, 7);
1595                         L_CERT(_PATH_HOST_XMSS_KEY_FILE, 8);
1596                         L_PUBKEY(_PATH_HOST_XMSS_KEY_FILE, 9);
1597                 }
1598         }
1599
1600         /* load options.identity_files */
1601         load_public_identity_files(cinfo);
1602
1603         /* optionally set the SSH_AUTHSOCKET_ENV_NAME variable */
1604         if (options.identity_agent &&
1605             strcmp(options.identity_agent, SSH_AUTHSOCKET_ENV_NAME) != 0) {
1606                 if (strcmp(options.identity_agent, "none") == 0) {
1607                         unsetenv(SSH_AUTHSOCKET_ENV_NAME);
1608                 } else {
1609                         cp = options.identity_agent;
1610                         /* legacy (limited) format */
1611                         if (cp[0] == '$' && cp[1] != '{') {
1612                                 if (!valid_env_name(cp + 1)) {
1613                                         fatal("Invalid IdentityAgent "
1614                                             "environment variable name %s", cp);
1615                                 }
1616                                 if ((p = getenv(cp + 1)) == NULL)
1617                                         unsetenv(SSH_AUTHSOCKET_ENV_NAME);
1618                                 else
1619                                         setenv(SSH_AUTHSOCKET_ENV_NAME, p, 1);
1620                         } else {
1621                                 /* identity_agent specifies a path directly */
1622                                 setenv(SSH_AUTHSOCKET_ENV_NAME, cp, 1);
1623                         }
1624                 }
1625         }
1626
1627         if (options.forward_agent && options.forward_agent_sock_path != NULL) {
1628                 cp = options.forward_agent_sock_path;
1629                 if (cp[0] == '$') {
1630                         if (!valid_env_name(cp + 1)) {
1631                                 fatal("Invalid ForwardAgent environment variable name %s", cp);
1632                         }
1633                         if ((p = getenv(cp + 1)) != NULL)
1634                                 forward_agent_sock_path = xstrdup(p);
1635                         else
1636                                 options.forward_agent = 0;
1637                         free(cp);
1638                 } else {
1639                         forward_agent_sock_path = cp;
1640                 }
1641         }
1642
1643         /* Expand ~ in known host file names. */
1644         tilde_expand_paths(options.system_hostfiles,
1645             options.num_system_hostfiles);
1646         tilde_expand_paths(options.user_hostfiles, options.num_user_hostfiles);
1647
1648         ssh_signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */
1649         ssh_signal(SIGCHLD, main_sigchld_handler);
1650
1651         /* Log into the remote system.  Never returns if the login fails. */
1652         ssh_login(ssh, &sensitive_data, host, (struct sockaddr *)&hostaddr,
1653             options.port, pw, timeout_ms, cinfo);
1654
1655         /* We no longer need the private host keys.  Clear them now. */
1656         if (sensitive_data.nkeys != 0) {
1657                 for (i = 0; i < sensitive_data.nkeys; i++) {
1658                         if (sensitive_data.keys[i] != NULL) {
1659                                 /* Destroys contents safely */
1660                                 debug3("clear hostkey %d", i);
1661                                 sshkey_free(sensitive_data.keys[i]);
1662                                 sensitive_data.keys[i] = NULL;
1663                         }
1664                 }
1665                 free(sensitive_data.keys);
1666         }
1667         for (i = 0; i < options.num_identity_files; i++) {
1668                 free(options.identity_files[i]);
1669                 options.identity_files[i] = NULL;
1670                 if (options.identity_keys[i]) {
1671                         sshkey_free(options.identity_keys[i]);
1672                         options.identity_keys[i] = NULL;
1673                 }
1674         }
1675         for (i = 0; i < options.num_certificate_files; i++) {
1676                 free(options.certificate_files[i]);
1677                 options.certificate_files[i] = NULL;
1678         }
1679
1680 #ifdef ENABLE_PKCS11
1681         (void)pkcs11_del_provider(options.pkcs11_provider);
1682 #endif
1683
1684  skip_connect:
1685         exit_status = ssh_session2(ssh, cinfo);
1686         ssh_conn_info_free(cinfo);
1687         ssh_packet_close(ssh);
1688
1689         if (options.control_path != NULL && muxserver_sock != -1)
1690                 unlink(options.control_path);
1691
1692         /* Kill ProxyCommand if it is running. */
1693         ssh_kill_proxy_command();
1694
1695         return exit_status;
1696 }
1697
1698 static void
1699 control_persist_detach(void)
1700 {
1701         pid_t pid;
1702
1703         debug_f("backgrounding master process");
1704
1705         /*
1706          * master (current process) into the background, and make the
1707          * foreground process a client of the backgrounded master.
1708          */
1709         switch ((pid = fork())) {
1710         case -1:
1711                 fatal_f("fork: %s", strerror(errno));
1712         case 0:
1713                 /* Child: master process continues mainloop */
1714                 break;
1715         default:
1716                 /* Parent: set up mux client to connect to backgrounded master */
1717                 debug2_f("background process is %ld", (long)pid);
1718                 options.stdin_null = ostdin_null_flag;
1719                 options.request_tty = orequest_tty;
1720                 tty_flag = otty_flag;
1721                 options.session_type = osession_type;
1722                 close(muxserver_sock);
1723                 muxserver_sock = -1;
1724                 options.control_master = SSHCTL_MASTER_NO;
1725                 muxclient(options.control_path);
1726                 /* muxclient() doesn't return on success. */
1727                 fatal("Failed to connect to new control master");
1728         }
1729         if (stdfd_devnull(1, 1, !(log_is_on_stderr() && debug_flag)) == -1)
1730                 error_f("stdfd_devnull failed");
1731         daemon(1, 1);
1732         setproctitle("%s [mux]", options.control_path);
1733 }
1734
1735 /* Do fork() after authentication. Used by "ssh -f" */
1736 static void
1737 fork_postauth(void)
1738 {
1739         if (need_controlpersist_detach)
1740                 control_persist_detach();
1741         debug("forking to background");
1742         options.fork_after_authentication = 0;
1743         if (daemon(1, 1) == -1)
1744                 fatal("daemon() failed: %.200s", strerror(errno));
1745         if (stdfd_devnull(1, 1, !(log_is_on_stderr() && debug_flag)) == -1)
1746                 error_f("stdfd_devnull failed");
1747 }
1748
1749 static void
1750 forwarding_success(void)
1751 {
1752         if (forward_confirms_pending == -1)
1753                 return;
1754         if (--forward_confirms_pending == 0) {
1755                 debug_f("all expected forwarding replies received");
1756                 if (options.fork_after_authentication)
1757                         fork_postauth();
1758         } else {
1759                 debug2_f("%d expected forwarding replies remaining",
1760                     forward_confirms_pending);
1761         }
1762 }
1763
1764 /* Callback for remote forward global requests */
1765 static void
1766 ssh_confirm_remote_forward(struct ssh *ssh, int type, u_int32_t seq, void *ctxt)
1767 {
1768         struct Forward *rfwd = (struct Forward *)ctxt;
1769         u_int port;
1770         int r;
1771
1772         /* XXX verbose() on failure? */
1773         debug("remote forward %s for: listen %s%s%d, connect %s:%d",
1774             type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure",
1775             rfwd->listen_path ? rfwd->listen_path :
1776             rfwd->listen_host ? rfwd->listen_host : "",
1777             (rfwd->listen_path || rfwd->listen_host) ? ":" : "",
1778             rfwd->listen_port, rfwd->connect_path ? rfwd->connect_path :
1779             rfwd->connect_host, rfwd->connect_port);
1780         if (rfwd->listen_path == NULL && rfwd->listen_port == 0) {
1781                 if (type == SSH2_MSG_REQUEST_SUCCESS) {
1782                         if ((r = sshpkt_get_u32(ssh, &port)) != 0)
1783                                 fatal_fr(r, "parse packet");
1784                         if (port > 65535) {
1785                                 error("Invalid allocated port %u for remote "
1786                                     "forward to %s:%d", port,
1787                                     rfwd->connect_host, rfwd->connect_port);
1788                                 /* Ensure failure processing runs below */
1789                                 type = SSH2_MSG_REQUEST_FAILURE;
1790                                 channel_update_permission(ssh,
1791                                     rfwd->handle, -1);
1792                         } else {
1793                                 rfwd->allocated_port = (int)port;
1794                                 logit("Allocated port %u for remote "
1795                                     "forward to %s:%d",
1796                                     rfwd->allocated_port, rfwd->connect_path ?
1797                                     rfwd->connect_path : rfwd->connect_host,
1798                                     rfwd->connect_port);
1799                                 channel_update_permission(ssh,
1800                                     rfwd->handle, rfwd->allocated_port);
1801                         }
1802                 } else {
1803                         channel_update_permission(ssh, rfwd->handle, -1);
1804                 }
1805         }
1806
1807         if (type == SSH2_MSG_REQUEST_FAILURE) {
1808                 if (options.exit_on_forward_failure) {
1809                         if (rfwd->listen_path != NULL)
1810                                 fatal("Error: remote port forwarding failed "
1811                                     "for listen path %s", rfwd->listen_path);
1812                         else
1813                                 fatal("Error: remote port forwarding failed "
1814                                     "for listen port %d", rfwd->listen_port);
1815                 } else {
1816                         if (rfwd->listen_path != NULL)
1817                                 logit("Warning: remote port forwarding failed "
1818                                     "for listen path %s", rfwd->listen_path);
1819                         else
1820                                 logit("Warning: remote port forwarding failed "
1821                                     "for listen port %d", rfwd->listen_port);
1822                 }
1823         }
1824         forwarding_success();
1825 }
1826
1827 static void
1828 client_cleanup_stdio_fwd(struct ssh *ssh, int id, void *arg)
1829 {
1830         debug("stdio forwarding: done");
1831         cleanup_exit(0);
1832 }
1833
1834 static void
1835 ssh_stdio_confirm(struct ssh *ssh, int id, int success, void *arg)
1836 {
1837         if (!success)
1838                 fatal("stdio forwarding failed");
1839 }
1840
1841 static void
1842 ssh_tun_confirm(struct ssh *ssh, int id, int success, void *arg)
1843 {
1844         if (!success) {
1845                 error("Tunnel forwarding failed");
1846                 if (options.exit_on_forward_failure)
1847                         cleanup_exit(255);
1848         }
1849
1850         debug_f("tunnel forward established, id=%d", id);
1851         forwarding_success();
1852 }
1853
1854 static void
1855 ssh_init_stdio_forwarding(struct ssh *ssh)
1856 {
1857         Channel *c;
1858         int in, out;
1859
1860         if (options.stdio_forward_host == NULL)
1861                 return;
1862
1863         debug3_f("%s:%d", options.stdio_forward_host,
1864             options.stdio_forward_port);
1865
1866         if ((in = dup(STDIN_FILENO)) == -1 ||
1867             (out = dup(STDOUT_FILENO)) == -1)
1868                 fatal_f("dup() in/out failed");
1869         if ((c = channel_connect_stdio_fwd(ssh, options.stdio_forward_host,
1870             options.stdio_forward_port, in, out,
1871             CHANNEL_NONBLOCK_STDIO)) == NULL)
1872                 fatal_f("channel_connect_stdio_fwd failed");
1873         channel_register_cleanup(ssh, c->self, client_cleanup_stdio_fwd, 0);
1874         channel_register_open_confirm(ssh, c->self, ssh_stdio_confirm, NULL);
1875 }
1876
1877 static void
1878 ssh_init_forward_permissions(struct ssh *ssh, const char *what, char **opens,
1879     u_int num_opens)
1880 {
1881         u_int i;
1882         int port;
1883         char *addr, *arg, *oarg, ch;
1884         int where = FORWARD_LOCAL;
1885
1886         channel_clear_permission(ssh, FORWARD_ADM, where);
1887         if (num_opens == 0)
1888                 return; /* permit any */
1889
1890         /* handle keywords: "any" / "none" */
1891         if (num_opens == 1 && strcmp(opens[0], "any") == 0)
1892                 return;
1893         if (num_opens == 1 && strcmp(opens[0], "none") == 0) {
1894                 channel_disable_admin(ssh, where);
1895                 return;
1896         }
1897         /* Otherwise treat it as a list of permitted host:port */
1898         for (i = 0; i < num_opens; i++) {
1899                 oarg = arg = xstrdup(opens[i]);
1900                 ch = '\0';
1901                 addr = hpdelim2(&arg, &ch);
1902                 if (addr == NULL || ch == '/')
1903                         fatal_f("missing host in %s", what);
1904                 addr = cleanhostname(addr);
1905                 if (arg == NULL || ((port = permitopen_port(arg)) < 0))
1906                         fatal_f("bad port number in %s", what);
1907                 /* Send it to channels layer */
1908                 channel_add_permission(ssh, FORWARD_ADM,
1909                     where, addr, port);
1910                 free(oarg);
1911         }
1912 }
1913
1914 static void
1915 ssh_init_forwarding(struct ssh *ssh, char **ifname)
1916 {
1917         int success = 0;
1918         int i;
1919
1920         ssh_init_forward_permissions(ssh, "permitremoteopen",
1921             options.permitted_remote_opens,
1922             options.num_permitted_remote_opens);
1923
1924         if (options.exit_on_forward_failure)
1925                 forward_confirms_pending = 0; /* track pending requests */
1926         /* Initiate local TCP/IP port forwardings. */
1927         for (i = 0; i < options.num_local_forwards; i++) {
1928                 debug("Local connections to %.200s:%d forwarded to remote "
1929                     "address %.200s:%d",
1930                     (options.local_forwards[i].listen_path != NULL) ?
1931                     options.local_forwards[i].listen_path :
1932                     (options.local_forwards[i].listen_host == NULL) ?
1933                     (options.fwd_opts.gateway_ports ? "*" : "LOCALHOST") :
1934                     options.local_forwards[i].listen_host,
1935                     options.local_forwards[i].listen_port,
1936                     (options.local_forwards[i].connect_path != NULL) ?
1937                     options.local_forwards[i].connect_path :
1938                     options.local_forwards[i].connect_host,
1939                     options.local_forwards[i].connect_port);
1940                 success += channel_setup_local_fwd_listener(ssh,
1941                     &options.local_forwards[i], &options.fwd_opts);
1942         }
1943         if (i > 0 && success != i && options.exit_on_forward_failure)
1944                 fatal("Could not request local forwarding.");
1945         if (i > 0 && success == 0)
1946                 error("Could not request local forwarding.");
1947
1948         /* Initiate remote TCP/IP port forwardings. */
1949         for (i = 0; i < options.num_remote_forwards; i++) {
1950                 debug("Remote connections from %.200s:%d forwarded to "
1951                     "local address %.200s:%d",
1952                     (options.remote_forwards[i].listen_path != NULL) ?
1953                     options.remote_forwards[i].listen_path :
1954                     (options.remote_forwards[i].listen_host == NULL) ?
1955                     "LOCALHOST" : options.remote_forwards[i].listen_host,
1956                     options.remote_forwards[i].listen_port,
1957                     (options.remote_forwards[i].connect_path != NULL) ?
1958                     options.remote_forwards[i].connect_path :
1959                     options.remote_forwards[i].connect_host,
1960                     options.remote_forwards[i].connect_port);
1961                 if ((options.remote_forwards[i].handle =
1962                     channel_request_remote_forwarding(ssh,
1963                     &options.remote_forwards[i])) >= 0) {
1964                         client_register_global_confirm(
1965                             ssh_confirm_remote_forward,
1966                             &options.remote_forwards[i]);
1967                         forward_confirms_pending++;
1968                 } else if (options.exit_on_forward_failure)
1969                         fatal("Could not request remote forwarding.");
1970                 else
1971                         logit("Warning: Could not request remote forwarding.");
1972         }
1973
1974         /* Initiate tunnel forwarding. */
1975         if (options.tun_open != SSH_TUNMODE_NO) {
1976                 if ((*ifname = client_request_tun_fwd(ssh,
1977                     options.tun_open, options.tun_local,
1978                     options.tun_remote, ssh_tun_confirm, NULL)) != NULL)
1979                         forward_confirms_pending++;
1980                 else if (options.exit_on_forward_failure)
1981                         fatal("Could not request tunnel forwarding.");
1982                 else
1983                         error("Could not request tunnel forwarding.");
1984         }
1985         if (forward_confirms_pending > 0) {
1986                 debug_f("expecting replies for %d forwards",
1987                     forward_confirms_pending);
1988         }
1989 }
1990
1991 static void
1992 check_agent_present(void)
1993 {
1994         int r;
1995
1996         if (options.forward_agent) {
1997                 /* Clear agent forwarding if we don't have an agent. */
1998                 if ((r = ssh_get_authentication_socket(NULL)) != 0) {
1999                         options.forward_agent = 0;
2000                         if (r != SSH_ERR_AGENT_NOT_PRESENT)
2001                                 debug_r(r, "ssh_get_authentication_socket");
2002                 }
2003         }
2004 }
2005
2006 static void
2007 ssh_session2_setup(struct ssh *ssh, int id, int success, void *arg)
2008 {
2009         extern char **environ;
2010         const char *display, *term;
2011         int r, interactive = tty_flag;
2012         char *proto = NULL, *data = NULL;
2013
2014         if (!success)
2015                 return; /* No need for error message, channels code sens one */
2016
2017         display = getenv("DISPLAY");
2018         if (display == NULL && options.forward_x11)
2019                 debug("X11 forwarding requested but DISPLAY not set");
2020         if (options.forward_x11 && client_x11_get_proto(ssh, display,
2021             options.xauth_location, options.forward_x11_trusted,
2022             options.forward_x11_timeout, &proto, &data) == 0) {
2023                 /* Request forwarding with authentication spoofing. */
2024                 debug("Requesting X11 forwarding with authentication "
2025                     "spoofing.");
2026                 x11_request_forwarding_with_spoofing(ssh, id, display, proto,
2027                     data, 1);
2028                 client_expect_confirm(ssh, id, "X11 forwarding", CONFIRM_WARN);
2029                 /* XXX exit_on_forward_failure */
2030                 interactive = 1;
2031         }
2032
2033         check_agent_present();
2034         if (options.forward_agent) {
2035                 debug("Requesting authentication agent forwarding.");
2036                 channel_request_start(ssh, id, "auth-agent-req@openssh.com", 0);
2037                 if ((r = sshpkt_send(ssh)) != 0)
2038                         fatal_fr(r, "send packet");
2039         }
2040
2041         /* Tell the packet module whether this is an interactive session. */
2042         ssh_packet_set_interactive(ssh, interactive,
2043             options.ip_qos_interactive, options.ip_qos_bulk);
2044
2045         if ((term = lookup_env_in_list("TERM", options.setenv,
2046             options.num_setenv)) == NULL || *term == '\0')
2047                 term = getenv("TERM");
2048         client_session2_setup(ssh, id, tty_flag,
2049             options.session_type == SESSION_TYPE_SUBSYSTEM, term,
2050             NULL, fileno(stdin), command, environ);
2051 }
2052
2053 /* open new channel for a session */
2054 static int
2055 ssh_session2_open(struct ssh *ssh)
2056 {
2057         Channel *c;
2058         int window, packetmax, in, out, err;
2059
2060         if (options.stdin_null) {
2061                 in = open(_PATH_DEVNULL, O_RDONLY);
2062         } else {
2063                 in = dup(STDIN_FILENO);
2064         }
2065         out = dup(STDOUT_FILENO);
2066         err = dup(STDERR_FILENO);
2067
2068         if (in == -1 || out == -1 || err == -1)
2069                 fatal("dup() in/out/err failed");
2070
2071         window = CHAN_SES_WINDOW_DEFAULT;
2072         packetmax = CHAN_SES_PACKET_DEFAULT;
2073         if (tty_flag) {
2074                 window >>= 1;
2075                 packetmax >>= 1;
2076         }
2077         c = channel_new(ssh,
2078             "session", SSH_CHANNEL_OPENING, in, out, err,
2079             window, packetmax, CHAN_EXTENDED_WRITE,
2080             "client-session", CHANNEL_NONBLOCK_STDIO);
2081
2082         debug3_f("channel_new: %d", c->self);
2083
2084         channel_send_open(ssh, c->self);
2085         if (options.session_type != SESSION_TYPE_NONE)
2086                 channel_register_open_confirm(ssh, c->self,
2087                     ssh_session2_setup, NULL);
2088
2089         return c->self;
2090 }
2091
2092 static int
2093 ssh_session2(struct ssh *ssh, const struct ssh_conn_info *cinfo)
2094 {
2095         int r, id = -1;
2096         char *cp, *tun_fwd_ifname = NULL;
2097
2098         /* XXX should be pre-session */
2099         if (!options.control_persist)
2100                 ssh_init_stdio_forwarding(ssh);
2101
2102         ssh_init_forwarding(ssh, &tun_fwd_ifname);
2103
2104         if (options.local_command != NULL) {
2105                 debug3("expanding LocalCommand: %s", options.local_command);
2106                 cp = options.local_command;
2107                 options.local_command = percent_expand(cp,
2108                     DEFAULT_CLIENT_PERCENT_EXPAND_ARGS(cinfo),
2109                     "T", tun_fwd_ifname == NULL ? "NONE" : tun_fwd_ifname,
2110                     (char *)NULL);
2111                 debug3("expanded LocalCommand: %s", options.local_command);
2112                 free(cp);
2113         }
2114
2115         /* Start listening for multiplex clients */
2116         if (!ssh_packet_get_mux(ssh))
2117                 muxserver_listen(ssh);
2118
2119         /*
2120          * If we are in control persist mode and have a working mux listen
2121          * socket, then prepare to background ourselves and have a foreground
2122          * client attach as a control client.
2123          * NB. we must save copies of the flags that we override for
2124          * the backgrounding, since we defer attachment of the client until
2125          * after the connection is fully established (in particular,
2126          * async rfwd replies have been received for ExitOnForwardFailure).
2127          */
2128         if (options.control_persist && muxserver_sock != -1) {
2129                 ostdin_null_flag = options.stdin_null;
2130                 osession_type = options.session_type;
2131                 orequest_tty = options.request_tty;
2132                 otty_flag = tty_flag;
2133                 options.stdin_null = 1;
2134                 options.session_type = SESSION_TYPE_NONE;
2135                 tty_flag = 0;
2136                 if (!options.fork_after_authentication &&
2137                     (osession_type != SESSION_TYPE_NONE ||
2138                     options.stdio_forward_host != NULL))
2139                         need_controlpersist_detach = 1;
2140                 options.fork_after_authentication = 1;
2141         }
2142         /*
2143          * ControlPersist mux listen socket setup failed, attempt the
2144          * stdio forward setup that we skipped earlier.
2145          */
2146         if (options.control_persist && muxserver_sock == -1)
2147                 ssh_init_stdio_forwarding(ssh);
2148
2149         if (options.session_type != SESSION_TYPE_NONE)
2150                 id = ssh_session2_open(ssh);
2151         else {
2152                 ssh_packet_set_interactive(ssh,
2153                     options.control_master == SSHCTL_MASTER_NO,
2154                     options.ip_qos_interactive, options.ip_qos_bulk);
2155         }
2156
2157         /* If we don't expect to open a new session, then disallow it */
2158         if (options.control_master == SSHCTL_MASTER_NO &&
2159             (ssh->compat & SSH_NEW_OPENSSH)) {
2160                 debug("Requesting no-more-sessions@openssh.com");
2161                 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 ||
2162                     (r = sshpkt_put_cstring(ssh,
2163                     "no-more-sessions@openssh.com")) != 0 ||
2164                     (r = sshpkt_put_u8(ssh, 0)) != 0 ||
2165                     (r = sshpkt_send(ssh)) != 0)
2166                         fatal_fr(r, "send packet");
2167         }
2168
2169         /* Execute a local command */
2170         if (options.local_command != NULL &&
2171             options.permit_local_command)
2172                 ssh_local_cmd(options.local_command);
2173
2174         /*
2175          * stdout is now owned by the session channel; clobber it here
2176          * so future channel closes are propagated to the local fd.
2177          * NB. this can only happen after LocalCommand has completed,
2178          * as it may want to write to stdout.
2179          */
2180         if (!need_controlpersist_detach && stdfd_devnull(0, 1, 0) == -1)
2181                 error_f("stdfd_devnull failed");
2182
2183         /*
2184          * If requested and we are not interested in replies to remote
2185          * forwarding requests, then let ssh continue in the background.
2186          */
2187         if (options.fork_after_authentication) {
2188                 if (options.exit_on_forward_failure &&
2189                     options.num_remote_forwards > 0) {
2190                         debug("deferring postauth fork until remote forward "
2191                             "confirmation received");
2192                 } else
2193                         fork_postauth();
2194         }
2195
2196         return client_loop(ssh, tty_flag, tty_flag ?
2197             options.escape_char : SSH_ESCAPECHAR_NONE, id);
2198 }
2199
2200 /* Loads all IdentityFile and CertificateFile keys */
2201 static void
2202 load_public_identity_files(const struct ssh_conn_info *cinfo)
2203 {
2204         char *filename, *cp;
2205         struct sshkey *public;
2206         int i;
2207         u_int n_ids, n_certs;
2208         char *identity_files[SSH_MAX_IDENTITY_FILES];
2209         struct sshkey *identity_keys[SSH_MAX_IDENTITY_FILES];
2210         int identity_file_userprovided[SSH_MAX_IDENTITY_FILES];
2211         char *certificate_files[SSH_MAX_CERTIFICATE_FILES];
2212         struct sshkey *certificates[SSH_MAX_CERTIFICATE_FILES];
2213         int certificate_file_userprovided[SSH_MAX_CERTIFICATE_FILES];
2214 #ifdef ENABLE_PKCS11
2215         struct sshkey **keys = NULL;
2216         char **comments = NULL;
2217         int nkeys;
2218 #endif /* PKCS11 */
2219
2220         n_ids = n_certs = 0;
2221         memset(identity_files, 0, sizeof(identity_files));
2222         memset(identity_keys, 0, sizeof(identity_keys));
2223         memset(identity_file_userprovided, 0,
2224             sizeof(identity_file_userprovided));
2225         memset(certificate_files, 0, sizeof(certificate_files));
2226         memset(certificates, 0, sizeof(certificates));
2227         memset(certificate_file_userprovided, 0,
2228             sizeof(certificate_file_userprovided));
2229
2230 #ifdef ENABLE_PKCS11
2231         if (options.pkcs11_provider != NULL &&
2232             options.num_identity_files < SSH_MAX_IDENTITY_FILES &&
2233             (pkcs11_init(!options.batch_mode) == 0) &&
2234             (nkeys = pkcs11_add_provider(options.pkcs11_provider, NULL,
2235             &keys, &comments)) > 0) {
2236                 for (i = 0; i < nkeys; i++) {
2237                         if (n_ids >= SSH_MAX_IDENTITY_FILES) {
2238                                 sshkey_free(keys[i]);
2239                                 free(comments[i]);
2240                                 continue;
2241                         }
2242                         identity_keys[n_ids] = keys[i];
2243                         identity_files[n_ids] = comments[i]; /* transferred */
2244                         n_ids++;
2245                 }
2246                 free(keys);
2247                 free(comments);
2248         }
2249 #endif /* ENABLE_PKCS11 */
2250         for (i = 0; i < options.num_identity_files; i++) {
2251                 if (n_ids >= SSH_MAX_IDENTITY_FILES ||
2252                     strcasecmp(options.identity_files[i], "none") == 0) {
2253                         free(options.identity_files[i]);
2254                         options.identity_files[i] = NULL;
2255                         continue;
2256                 }
2257                 cp = tilde_expand_filename(options.identity_files[i], getuid());
2258                 filename = default_client_percent_dollar_expand(cp, cinfo);
2259                 free(cp);
2260                 check_load(sshkey_load_public(filename, &public, NULL),
2261                     filename, "pubkey");
2262                 debug("identity file %s type %d", filename,
2263                     public ? public->type : -1);
2264                 free(options.identity_files[i]);
2265                 identity_files[n_ids] = filename;
2266                 identity_keys[n_ids] = public;
2267                 identity_file_userprovided[n_ids] =
2268                     options.identity_file_userprovided[i];
2269                 if (++n_ids >= SSH_MAX_IDENTITY_FILES)
2270                         continue;
2271
2272                 /*
2273                  * If no certificates have been explicitly listed then try
2274                  * to add the default certificate variant too.
2275                  */
2276                 if (options.num_certificate_files != 0)
2277                         continue;
2278                 xasprintf(&cp, "%s-cert", filename);
2279                 check_load(sshkey_load_public(cp, &public, NULL),
2280                     filename, "pubkey");
2281                 debug("identity file %s type %d", cp,
2282                     public ? public->type : -1);
2283                 if (public == NULL) {
2284                         free(cp);
2285                         continue;
2286                 }
2287                 if (!sshkey_is_cert(public)) {
2288                         debug_f("key %s type %s is not a certificate",
2289                             cp, sshkey_type(public));
2290                         sshkey_free(public);
2291                         free(cp);
2292                         continue;
2293                 }
2294                 /* NB. leave filename pointing to private key */
2295                 identity_files[n_ids] = xstrdup(filename);
2296                 identity_keys[n_ids] = public;
2297                 identity_file_userprovided[n_ids] =
2298                     options.identity_file_userprovided[i];
2299                 n_ids++;
2300         }
2301
2302         if (options.num_certificate_files > SSH_MAX_CERTIFICATE_FILES)
2303                 fatal_f("too many certificates");
2304         for (i = 0; i < options.num_certificate_files; i++) {
2305                 cp = tilde_expand_filename(options.certificate_files[i],
2306                     getuid());
2307                 filename = default_client_percent_dollar_expand(cp, cinfo);
2308                 free(cp);
2309
2310                 check_load(sshkey_load_public(filename, &public, NULL),
2311                     filename, "certificate");
2312                 debug("certificate file %s type %d", filename,
2313                     public ? public->type : -1);
2314                 free(options.certificate_files[i]);
2315                 options.certificate_files[i] = NULL;
2316                 if (public == NULL) {
2317                         free(filename);
2318                         continue;
2319                 }
2320                 if (!sshkey_is_cert(public)) {
2321                         debug_f("key %s type %s is not a certificate",
2322                             filename, sshkey_type(public));
2323                         sshkey_free(public);
2324                         free(filename);
2325                         continue;
2326                 }
2327                 certificate_files[n_certs] = filename;
2328                 certificates[n_certs] = public;
2329                 certificate_file_userprovided[n_certs] =
2330                     options.certificate_file_userprovided[i];
2331                 ++n_certs;
2332         }
2333
2334         options.num_identity_files = n_ids;
2335         memcpy(options.identity_files, identity_files, sizeof(identity_files));
2336         memcpy(options.identity_keys, identity_keys, sizeof(identity_keys));
2337         memcpy(options.identity_file_userprovided,
2338             identity_file_userprovided, sizeof(identity_file_userprovided));
2339
2340         options.num_certificate_files = n_certs;
2341         memcpy(options.certificate_files,
2342             certificate_files, sizeof(certificate_files));
2343         memcpy(options.certificates, certificates, sizeof(certificates));
2344         memcpy(options.certificate_file_userprovided,
2345             certificate_file_userprovided,
2346             sizeof(certificate_file_userprovided));
2347 }
2348
2349 static void
2350 main_sigchld_handler(int sig)
2351 {
2352         int save_errno = errno;
2353         pid_t pid;
2354         int status;
2355
2356         while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
2357             (pid == -1 && errno == EINTR))
2358                 ;
2359         errno = save_errno;
2360 }