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 __RCSID("$FreeBSD$");
  45
  46 #include <sys/types.h>
  47 #ifdef HAVE_SYS_STAT_H
  48 # include <sys/stat.h>
  49 #endif
  50 #include <sys/resource.h>
  51 #include <sys/ioctl.h>
  52 #include <sys/socket.h>
  53 #include <sys/wait.h>
  54
  55 #include <ctype.h>
  56 #include <errno.h>
  57 #include <fcntl.h>
  58 #include <netdb.h>
  59 #ifdef HAVE_PATHS_H
  60 #include <paths.h>
  61 #endif
  62 #include <pwd.h>
  63 #include <signal.h>
  64 #include <stdarg.h>
  65 #include <stddef.h>
  66 #include <stdio.h>
  67 #include <stdlib.h>
  68 #include <string.h>
  69 #include <stdarg.h>
  70 #include <unistd.h>
  71 #include <limits.h>
  72 #include <locale.h>
  73
  74 #include <netinet/in.h>
  75 #include <arpa/inet.h>
  76
  77 #ifdef WITH_OPENSSL
  78 #include <openssl/evp.h>
  79 #include <openssl/err.h>
  80 #endif
  81 #include "openbsd-compat/openssl-compat.h"
  82 #include "openbsd-compat/sys-queue.h"
  83
  84 #include "xmalloc.h"
  85 #include "ssh.h"
  86 #include "ssh2.h"
  87 #include "canohost.h"
  88 #include "compat.h"
  89 #include "cipher.h"
  90 #include "packet.h"
  91 #include "sshbuf.h"
  92 #include "channels.h"
  93 #include "sshkey.h"
  94 #include "authfd.h"
  95 #include "authfile.h"
  96 #include "pathnames.h"
  97 #include "dispatch.h"
  98 #include "clientloop.h"
  99 #include "log.h"
 100 #include "misc.h"
 101 #include "readconf.h"
 102 #include "sshconnect.h"
 103 #include "kex.h"
 104 #include "mac.h"
 105 #include "sshpty.h"
 106 #include "match.h"
 107 #include "msg.h"
 108 #include "version.h"
 109 #include "ssherr.h"
 110 #include "myproposal.h"
 111 #include "utf8.h"
 112
 113 #ifdef ENABLE_PKCS11
 114 #include "ssh-pkcs11.h"
 115 #endif
 116
 117 extern char *__progname;
 118
 119 /* Saves a copy of argv for setproctitle emulation */
 120 #ifndef HAVE_SETPROCTITLE
 121 static char **saved_av;
 122 #endif
 123
 124 /* Flag indicating whether debug mode is on.  May be set on the command line. */
 125 int debug_flag = 0;
 126
 127 /* Flag indicating whether a tty should be requested */
 128 int tty_flag = 0;
 129
 130 /*
 131  * Flag indicating that the current process should be backgrounded and
 132  * a new mux-client launched in the foreground for ControlPersist.
 133  */
 134 int need_controlpersist_detach = 0;
 135
 136 /* Copies of flags for ControlPersist foreground mux-client */
 137 int ostdin_null_flag, osession_type, otty_flag, orequest_tty;
 138
 139 /*
 140  * General data structure for command line options and options configurable
 141  * in configuration files.  See readconf.h.
 142  */
 143 Options options;
 144
 145 /* optional user configfile */
 146 char *config = NULL;
 147
 148 /*
 149  * Name of the host we are connecting to.  This is the name given on the
 150  * command line, or the Hostname specified for the user-supplied name in a
 151  * configuration file.
 152  */
 153 char *host;
 154
 155 /*
 156  * A config can specify a path to forward, overriding SSH_AUTH_SOCK. If this is
 157  * not NULL, forward the socket at this path instead.
 158  */
 159 char *forward_agent_sock_path = NULL;
 160
 161 /* socket address the host resolves to */
 162 struct sockaddr_storage hostaddr;
 163
 164 /* Private host keys. */
 165 Sensitive sensitive_data;
 166
 167 /* command to be executed */
 168 struct sshbuf *command;
 169
 170 /* # of replies received for global requests */
 171 static int forward_confirms_pending = -1;
 172
 173 /* mux.c */
 174 extern int muxserver_sock;
 175 extern u_int muxclient_command;
 176
 177 /* Prints a help message to the user.  This function never returns. */
 178
 179 static void
 180 usage(void)
 181 {
 182         fprintf(stderr,
 183 "usage: ssh [-46AaCfGgKkMNnqsTtVvXxYy] [-B bind_interface]\n"
 184 "           [-b bind_address] [-c cipher_spec] [-D [bind_address:]port]\n"
 185 "           [-E log_file] [-e escape_char] [-F configfile] [-I pkcs11]\n"
 186 "           [-i identity_file] [-J [user@]host[:port]] [-L address]\n"
 187 "           [-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port]\n"
 188 "           [-Q query_option] [-R address] [-S ctl_path] [-W host:port]\n"
 189 "           [-w local_tun[:remote_tun]] destination [command [argument ...]]\n"
 190         );
 191         exit(255);
 192 }
 193
 194 static int ssh_session2(struct ssh *, const struct ssh_conn_info *);
 195 static void load_public_identity_files(const struct ssh_conn_info *);
 196 static void main_sigchld_handler(int);
 197
 198 /* ~/ expand a list of paths. NB. assumes path[n] is heap-allocated. */
 199 static void
 200 tilde_expand_paths(char **paths, u_int num_paths)
 201 {
 202         u_int i;
 203         char *cp;
 204
 205         for (i = 0; i < num_paths; i++) {
 206                 cp = tilde_expand_filename(paths[i], getuid());
 207                 free(paths[i]);
 208                 paths[i] = cp;
 209         }
 210 }
 211
 212 /*
 213  * Expands the set of percent_expand options used by the majority of keywords
 214  * in the client that support percent expansion.
 215  * Caller must free returned string.
 216  */
 217 static char *
 218 default_client_percent_expand(const char *str,
 219     const struct ssh_conn_info *cinfo)
 220 {
 221         return percent_expand(str,
 222             DEFAULT_CLIENT_PERCENT_EXPAND_ARGS(cinfo),
 223             (char *)NULL);
 224 }
 225
 226 /*
 227  * Expands the set of percent_expand options used by the majority of keywords
 228  * AND perform environment variable substitution.
 229  * Caller must free returned string.
 230  */
 231 static char *
 232 default_client_percent_dollar_expand(const char *str,
 233     const struct ssh_conn_info *cinfo)
 234 {
 235         char *ret;
 236
 237         ret = percent_dollar_expand(str,
 238             DEFAULT_CLIENT_PERCENT_EXPAND_ARGS(cinfo),
 239             (char *)NULL);
 240         if (ret == NULL)
 241                 fatal("invalid environment variable expansion");
 242         return ret;
 243 }
 244
 245 /*
 246  * Attempt to resolve a host name / port to a set of addresses and
 247  * optionally return any CNAMEs encountered along the way.
 248  * Returns NULL on failure.
 249  * NB. this function must operate with a options having undefined members.
 250  */
 251 static struct addrinfo *
 252 resolve_host(const char *name, int port, int logerr, char *cname, size_t clen)
 253 {
 254         char strport[NI_MAXSERV];
 255         struct addrinfo hints, *res;
 256         int gaierr;
 257         LogLevel loglevel = SYSLOG_LEVEL_DEBUG1;
 258
 259         if (port <= 0)
 260                 port = default_ssh_port();
 261         if (cname != NULL)
 262                 *cname = '\0';
 263         debug3_f("lookup %s:%d", name, port);
 264
 265         snprintf(strport, sizeof strport, "%d", port);
 266         memset(&hints, 0, sizeof(hints));
 267         hints.ai_family = options.address_family == -1 ?
 268             AF_UNSPEC : options.address_family;
 269         hints.ai_socktype = SOCK_STREAM;
 270         if (cname != NULL)
 271                 hints.ai_flags = AI_CANONNAME;
 272         if ((gaierr = getaddrinfo(name, strport, &hints, &res)) != 0) {
 273                 if (logerr || (gaierr != EAI_NONAME && gaierr != EAI_NODATA))
 274                         loglevel = SYSLOG_LEVEL_ERROR;
 275                 do_log2(loglevel, "%s: Could not resolve hostname %.100s: %s",
 276                     __progname, name, ssh_gai_strerror(gaierr));
 277                 return NULL;
 278         }
 279         if (cname != NULL && res->ai_canonname != NULL) {
 280                 if (strlcpy(cname, res->ai_canonname, clen) >= clen) {
 281                         error_f("host \"%s\" cname \"%s\" too long (max %lu)",
 282                             name,  res->ai_canonname, (u_long)clen);
 283                         if (clen > 0)
 284                                 *cname = '\0';
 285                 }
 286         }
 287         return res;
 288 }
 289
 290 /* Returns non-zero if name can only be an address and not a hostname */
 291 static int
 292 is_addr_fast(const char *name)
 293 {
 294         return (strchr(name, '%') != NULL || strchr(name, ':') != NULL ||
 295             strspn(name, "0123456789.") == strlen(name));
 296 }
 297
 298 /* Returns non-zero if name represents a valid, single address */
 299 static int
 300 is_addr(const char *name)
 301 {
 302         char strport[NI_MAXSERV];
 303         struct addrinfo hints, *res;
 304
 305         if (is_addr_fast(name))
 306                 return 1;
 307
 308         snprintf(strport, sizeof strport, "%u", default_ssh_port());
 309         memset(&hints, 0, sizeof(hints));
 310         hints.ai_family = options.address_family == -1 ?
 311             AF_UNSPEC : options.address_family;
 312         hints.ai_socktype = SOCK_STREAM;
 313         hints.ai_flags = AI_NUMERICHOST|AI_NUMERICSERV;
 314         if (getaddrinfo(name, strport, &hints, &res) != 0)
 315                 return 0;
 316         if (res == NULL || res->ai_next != NULL) {
 317                 freeaddrinfo(res);
 318                 return 0;
 319         }
 320         freeaddrinfo(res);
 321         return 1;
 322 }
 323
 324 /*
 325  * Attempt to resolve a numeric host address / port to a single address.
 326  * Returns a canonical address string.
 327  * Returns NULL on failure.
 328  * NB. this function must operate with a options having undefined members.
 329  */
 330 static struct addrinfo *
 331 resolve_addr(const char *name, int port, char *caddr, size_t clen)
 332 {
 333         char addr[NI_MAXHOST], strport[NI_MAXSERV];
 334         struct addrinfo hints, *res;
 335         int gaierr;
 336
 337         if (port <= 0)
 338                 port = default_ssh_port();
 339         snprintf(strport, sizeof strport, "%u", port);
 340         memset(&hints, 0, sizeof(hints));
 341         hints.ai_family = options.address_family == -1 ?
 342             AF_UNSPEC : options.address_family;
 343         hints.ai_socktype = SOCK_STREAM;
 344         hints.ai_flags = AI_NUMERICHOST|AI_NUMERICSERV;
 345         if ((gaierr = getaddrinfo(name, strport, &hints, &res)) != 0) {
 346                 debug2_f("could not resolve name %.100s as address: %s",
 347                     name, ssh_gai_strerror(gaierr));
 348                 return NULL;
 349         }
 350         if (res == NULL) {
 351                 debug_f("getaddrinfo %.100s returned no addresses", name);
 352                 return NULL;
 353         }
 354         if (res->ai_next != NULL) {
 355                 debug_f("getaddrinfo %.100s returned multiple addresses", name);
 356                 goto fail;
 357         }
 358         if ((gaierr = getnameinfo(res->ai_addr, res->ai_addrlen,
 359             addr, sizeof(addr), NULL, 0, NI_NUMERICHOST)) != 0) {
 360                 debug_f("Could not format address for name %.100s: %s",
 361                     name, ssh_gai_strerror(gaierr));
 362                 goto fail;
 363         }
 364         if (strlcpy(caddr, addr, clen) >= clen) {
 365                 error_f("host \"%s\" addr \"%s\" too long (max %lu)",
 366                     name,  addr, (u_long)clen);
 367                 if (clen > 0)
 368                         *caddr = '\0';
 369  fail:
 370                 freeaddrinfo(res);
 371                 return NULL;
 372         }
 373         return res;
 374 }
 375
 376 /*
 377  * Check whether the cname is a permitted replacement for the hostname
 378  * and perform the replacement if it is.
 379  * NB. this function must operate with a options having undefined members.
 380  */
 381 static int
 382 check_follow_cname(int direct, char **namep, const char *cname)
 383 {
 384         int i;
 385         struct allowed_cname *rule;
 386
 387         if (*cname == '\0' || !config_has_permitted_cnames(&options) ||
 388             strcmp(*namep, cname) == 0)
 389                 return 0;
 390         if (options.canonicalize_hostname == SSH_CANONICALISE_NO)
 391                 return 0;
 392         /*
 393          * Don't attempt to canonicalize names that will be interpreted by
 394          * a proxy or jump host unless the user specifically requests so.
 395          */
 396         if (!direct &&
 397             options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS)
 398                 return 0;
 399         debug3_f("check \"%s\" CNAME \"%s\"", *namep, cname);
 400         for (i = 0; i < options.num_permitted_cnames; i++) {
 401                 rule = options.permitted_cnames + i;
 402                 if (match_pattern_list(*namep, rule->source_list, 1) != 1 ||
 403                     match_pattern_list(cname, rule->target_list, 1) != 1)
 404                         continue;
 405                 verbose("Canonicalized DNS aliased hostname "
 406                     "\"%s\" => \"%s\"", *namep, cname);
 407                 free(*namep);
 408                 *namep = xstrdup(cname);
 409                 return 1;
 410         }
 411         return 0;
 412 }
 413
 414 /*
 415  * Attempt to resolve the supplied hostname after applying the user's
 416  * canonicalization rules. Returns the address list for the host or NULL
 417  * if no name was found after canonicalization.
 418  * NB. this function must operate with a options having undefined members.
 419  */
 420 static struct addrinfo *
 421 resolve_canonicalize(char **hostp, int port)
 422 {
 423         int i, direct, ndots;
 424         char *cp, *fullhost, newname[NI_MAXHOST];
 425         struct addrinfo *addrs;
 426
 427         /*
 428          * Attempt to canonicalise addresses, regardless of
 429          * whether hostname canonicalisation was requested
 430          */
 431         if ((addrs = resolve_addr(*hostp, port,
 432             newname, sizeof(newname))) != NULL) {
 433                 debug2_f("hostname %.100s is address", *hostp);
 434                 if (strcasecmp(*hostp, newname) != 0) {
 435                         debug2_f("canonicalised address \"%s\" => \"%s\"",
 436                             *hostp, newname);
 437                         free(*hostp);
 438                         *hostp = xstrdup(newname);
 439                 }
 440                 return addrs;
 441         }
 442
 443         /*
 444          * If this looks like an address but didn't parse as one, it might
 445          * be an address with an invalid interface scope. Skip further
 446          * attempts at canonicalisation.
 447          */
 448         if (is_addr_fast(*hostp)) {
 449                 debug_f("hostname %.100s is an unrecognised address", *hostp);
 450                 return NULL;
 451         }
 452
 453         if (options.canonicalize_hostname == SSH_CANONICALISE_NO)
 454                 return NULL;
 455
 456         /*
 457          * Don't attempt to canonicalize names that will be interpreted by
 458          * a proxy unless the user specifically requests so.
 459          */
 460         direct = option_clear_or_none(options.proxy_command) &&
 461             options.jump_host == NULL;
 462         if (!direct &&
 463             options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS)
 464                 return NULL;
 465
 466         /* If domain name is anchored, then resolve it now */
 467         if ((*hostp)[strlen(*hostp) - 1] == '.') {
 468                 debug3_f("name is fully qualified");
 469                 fullhost = xstrdup(*hostp);
 470                 if ((addrs = resolve_host(fullhost, port, 0,
 471                     newname, sizeof(newname))) != NULL)
 472                         goto found;
 473                 free(fullhost);
 474                 goto notfound;
 475         }
 476
 477         /* Don't apply canonicalization to sufficiently-qualified hostnames */
 478         ndots = 0;
 479         for (cp = *hostp; *cp != '\0'; cp++) {
 480                 if (*cp == '.')
 481                         ndots++;
 482         }
 483         if (ndots > options.canonicalize_max_dots) {
 484                 debug3_f("not canonicalizing hostname \"%s\" (max dots %d)",
 485                     *hostp, options.canonicalize_max_dots);
 486                 return NULL;
 487         }
 488         /* Attempt each supplied suffix */
 489         for (i = 0; i < options.num_canonical_domains; i++) {
 490                 if (strcasecmp(options.canonical_domains[i], "none") == 0)
 491                         break;
 492                 xasprintf(&fullhost, "%s.%s.", *hostp,
 493                     options.canonical_domains[i]);
 494                 debug3_f("attempting \"%s\" => \"%s\"", *hostp, fullhost);
 495                 if ((addrs = resolve_host(fullhost, port, 0,
 496                     newname, sizeof(newname))) == NULL) {
 497                         free(fullhost);
 498                         continue;
 499                 }
 500  found:
 501                 /* Remove trailing '.' */
 502                 fullhost[strlen(fullhost) - 1] = '\0';
 503                 /* Follow CNAME if requested */
 504                 if (!check_follow_cname(direct, &fullhost, newname)) {
 505                         debug("Canonicalized hostname \"%s\" => \"%s\"",
 506                             *hostp, fullhost);
 507                 }
 508                 free(*hostp);
 509                 *hostp = fullhost;
 510                 return addrs;
 511         }
 512  notfound:
 513         if (!options.canonicalize_fallback_local)
 514                 fatal("%s: Could not resolve host \"%s\"", __progname, *hostp);
 515         debug2_f("host %s not found in any suffix", *hostp);
 516         return NULL;
 517 }
 518
 519 /*
 520  * Check the result of hostkey loading, ignoring some errors and
 521  * fatal()ing for others.
 522  */
 523 static void
 524 check_load(int r, const char *path, const char *message)
 525 {
 526         switch (r) {
 527         case 0:
 528                 break;
 529         case SSH_ERR_INTERNAL_ERROR:
 530         case SSH_ERR_ALLOC_FAIL:
 531                 fatal_r(r, "load %s \"%s\"", message, path);
 532         case SSH_ERR_SYSTEM_ERROR:
 533                 /* Ignore missing files */
 534                 if (errno == ENOENT)
 535                         break;
 536                 /* FALLTHROUGH */
 537         default:
 538                 error_r(r, "load %s \"%s\"", message, path);
 539                 break;
 540         }
 541 }
 542
 543 /*
 544  * Read per-user configuration file.  Ignore the system wide config
 545  * file if the user specifies a config file on the command line.
 546  */
 547 static void
 548 process_config_files(const char *host_name, struct passwd *pw, int final_pass,
 549     int *want_final_pass)
 550 {
 551         char buf[PATH_MAX];
 552         int r;
 553
 554         if (config != NULL) {
 555                 if (strcasecmp(config, "none") != 0 &&
 556                     !read_config_file(config, pw, host, host_name, &options,
 557                     SSHCONF_USERCONF | (final_pass ? SSHCONF_FINAL : 0),
 558                     want_final_pass))
 559                         fatal("Can't open user config file %.100s: "
 560                             "%.100s", config, strerror(errno));
 561         } else {
 562                 r = snprintf(buf, sizeof buf, "%s/%s", pw->pw_dir,
 563                     _PATH_SSH_USER_CONFFILE);
 564                 if (r > 0 && (size_t)r < sizeof(buf))
 565                         (void)read_config_file(buf, pw, host, host_name,
 566                             &options, SSHCONF_CHECKPERM | SSHCONF_USERCONF |
 567                             (final_pass ? SSHCONF_FINAL : 0), want_final_pass);
 568
 569                 /* Read systemwide configuration file after user config. */
 570                 (void)read_config_file(_PATH_HOST_CONFIG_FILE, pw,
 571                     host, host_name, &options,
 572                     final_pass ? SSHCONF_FINAL : 0, want_final_pass);
 573         }
 574 }
 575
 576 /* Rewrite the port number in an addrinfo list of addresses */
 577 static void
 578 set_addrinfo_port(struct addrinfo *addrs, int port)
 579 {
 580         struct addrinfo *addr;
 581
 582         for (addr = addrs; addr != NULL; addr = addr->ai_next) {
 583                 switch (addr->ai_family) {
 584                 case AF_INET:
 585                         ((struct sockaddr_in *)addr->ai_addr)->
 586                             sin_port = htons(port);
 587                         break;
 588                 case AF_INET6:
 589                         ((struct sockaddr_in6 *)addr->ai_addr)->
 590                             sin6_port = htons(port);
 591                         break;
 592                 }
 593         }
 594 }
 595
 596 static void
 597 ssh_conn_info_free(struct ssh_conn_info *cinfo)
 598 {
 599         if (cinfo == NULL)
 600                 return;
 601         free(cinfo->conn_hash_hex);
 602         free(cinfo->shorthost);
 603         free(cinfo->uidstr);
 604         free(cinfo->keyalias);
 605         free(cinfo->thishost);
 606         free(cinfo->host_arg);
 607         free(cinfo->portstr);
 608         free(cinfo->remhost);
 609         free(cinfo->remuser);
 610         free(cinfo->homedir);
 611         free(cinfo->locuser);
 612         free(cinfo);
 613 }
 614
 615 /*
 616  * Main program for the ssh client.
 617  */
 618 int
 619 main(int ac, char **av)
 620 {
 621         struct ssh *ssh = NULL;
 622         int i, r, opt, exit_status, use_syslog, direct, timeout_ms;
 623         int was_addr, config_test = 0, opt_terminated = 0, want_final_pass = 0;
 624         char *p, *cp, *line, *argv0, *logfile, *host_arg;
 625         char cname[NI_MAXHOST], thishost[NI_MAXHOST];
 626         struct stat st;
 627         struct passwd *pw;
 628         extern int optind, optreset;
 629         extern char *optarg;
 630         struct Forward fwd;
 631         struct addrinfo *addrs = NULL;
 632         size_t n, len;
 633         u_int j;
 634         struct ssh_conn_info *cinfo = NULL;
 635
 636         /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
 637         sanitise_stdfd();
 638
 639         /*
 640          * Discard other fds that are hanging around. These can cause problem
 641          * with backgrounded ssh processes started by ControlPersist.
 642          */
 643         closefrom(STDERR_FILENO + 1);
 644
 645         __progname = ssh_get_progname(av[0]);
 646
 647 #ifndef HAVE_SETPROCTITLE
 648         /* Prepare for later setproctitle emulation */
 649         /* Save argv so it isn't clobbered by setproctitle() emulation */
 650         saved_av = xcalloc(ac + 1, sizeof(*saved_av));
 651         for (i = 0; i < ac; i++)
 652                 saved_av[i] = xstrdup(av[i]);
 653         saved_av[i] = NULL;
 654         compat_init_setproctitle(ac, av);
 655         av = saved_av;
 656 #endif
 657
 658         seed_rng();
 659
 660         /* Get user data. */
 661         pw = getpwuid(getuid());
 662         if (!pw) {
 663                 logit("No user exists for uid %lu", (u_long)getuid());
 664                 exit(255);
 665         }
 666         /* Take a copy of the returned structure. */
 667         pw = pwcopy(pw);
 668
 669         /*
 670          * Set our umask to something reasonable, as some files are created
 671          * with the default umask.  This will make them world-readable but
 672          * writable only by the owner, which is ok for all files for which we
 673          * don't set the modes explicitly.
 674          */
 675         umask(022);
 676
 677         msetlocale();
 678
 679         /*
 680          * Initialize option structure to indicate that no values have been
 681          * set.
 682          */
 683         initialize_options(&options);
 684
 685         /*
 686          * Prepare main ssh transport/connection structures
 687          */
 688         if ((ssh = ssh_alloc_session_state()) == NULL)
 689                 fatal("Couldn't allocate session state");
 690         channel_init_channels(ssh);
 691
 692         /* Parse command-line arguments. */
 693         host = NULL;
 694         use_syslog = 0;
 695         logfile = NULL;
 696         argv0 = av[0];
 697
 698  again:
 699         while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx"
 700             "AB:CD:E:F:GI:J:KL:MNO:PQ:R:S:TVw:W:XYy")) != -1) {
 701                 switch (opt) {
 702                 case '1':
 703                         fatal("SSH protocol v.1 is no longer supported");
 704                         break;
 705                 case '2':
 706                         /* Ignored */
 707                         break;
 708                 case '4':
 709                         options.address_family = AF_INET;
 710                         break;
 711                 case '6':
 712                         options.address_family = AF_INET6;
 713                         break;
 714                 case 'n':
 715                         options.stdin_null = 1;
 716                         break;
 717                 case 'f':
 718                         options.fork_after_authentication = 1;
 719                         options.stdin_null = 1;
 720                         break;
 721                 case 'x':
 722                         options.forward_x11 = 0;
 723                         break;
 724                 case 'X':
 725                         options.forward_x11 = 1;
 726                         break;
 727                 case 'y':
 728                         use_syslog = 1;
 729                         break;
 730                 case 'E':
 731                         logfile = optarg;
 732                         break;
 733                 case 'G':
 734                         config_test = 1;
 735                         break;
 736                 case 'Y':
 737                         options.forward_x11 = 1;
 738                         options.forward_x11_trusted = 1;
 739                         break;
 740                 case 'g':
 741                         options.fwd_opts.gateway_ports = 1;
 742                         break;
 743                 case 'O':
 744                         if (options.stdio_forward_host != NULL)
 745                                 fatal("Cannot specify multiplexing "
 746                                     "command with -W");
 747                         else if (muxclient_command != 0)
 748                                 fatal("Multiplexing command already specified");
 749                         if (strcmp(optarg, "check") == 0)
 750                                 muxclient_command = SSHMUX_COMMAND_ALIVE_CHECK;
 751                         else if (strcmp(optarg, "forward") == 0)
 752                                 muxclient_command = SSHMUX_COMMAND_FORWARD;
 753                         else if (strcmp(optarg, "exit") == 0)
 754                                 muxclient_command = SSHMUX_COMMAND_TERMINATE;
 755                         else if (strcmp(optarg, "stop") == 0)
 756                                 muxclient_command = SSHMUX_COMMAND_STOP;
 757                         else if (strcmp(optarg, "cancel") == 0)
 758                                 muxclient_command = SSHMUX_COMMAND_CANCEL_FWD;
 759                         else if (strcmp(optarg, "proxy") == 0)
 760                                 muxclient_command = SSHMUX_COMMAND_PROXY;
 761                         else
 762                                 fatal("Invalid multiplex command.");
 763                         break;
 764                 case 'P':       /* deprecated */
 765                         break;
 766                 case 'Q':
 767                         cp = NULL;
 768                         if (strcmp(optarg, "cipher") == 0 ||
 769                             strcasecmp(optarg, "Ciphers") == 0)
 770                                 cp = cipher_alg_list('\n', 0);
 771                         else if (strcmp(optarg, "cipher-auth") == 0)
 772                                 cp = cipher_alg_list('\n', 1);
 773                         else if (strcmp(optarg, "mac") == 0 ||
 774                             strcasecmp(optarg, "MACs") == 0)
 775                                 cp = mac_alg_list('\n');
 776                         else if (strcmp(optarg, "kex") == 0 ||
 777                             strcasecmp(optarg, "KexAlgorithms") == 0)
 778                                 cp = kex_alg_list('\n');
 779                         else if (strcmp(optarg, "key") == 0)
 780                                 cp = sshkey_alg_list(0, 0, 0, '\n');
 781                         else if (strcmp(optarg, "key-cert") == 0)
 782                                 cp = sshkey_alg_list(1, 0, 0, '\n');
 783                         else if (strcmp(optarg, "key-plain") == 0)
 784                                 cp = sshkey_alg_list(0, 1, 0, '\n');
 785                         else if (strcmp(optarg, "key-sig") == 0 ||
 786                             strcasecmp(optarg, "PubkeyAcceptedKeyTypes") == 0 || /* deprecated name */
 787                             strcasecmp(optarg, "PubkeyAcceptedAlgorithms") == 0 ||
 788                             strcasecmp(optarg, "HostKeyAlgorithms") == 0 ||
 789                             strcasecmp(optarg, "HostbasedKeyTypes") == 0 || /* deprecated name */
 790                             strcasecmp(optarg, "HostbasedAcceptedKeyTypes") == 0 || /* deprecated name */
 791                             strcasecmp(optarg, "HostbasedAcceptedAlgorithms") == 0)
 792                                 cp = sshkey_alg_list(0, 0, 1, '\n');
 793                         else if (strcmp(optarg, "sig") == 0)
 794                                 cp = sshkey_alg_list(0, 1, 1, '\n');
 795                         else if (strcmp(optarg, "protocol-version") == 0)
 796                                 cp = xstrdup("2");
 797                         else if (strcmp(optarg, "compression") == 0) {
 798                                 cp = xstrdup(compression_alg_list(0));
 799                                 len = strlen(cp);
 800                                 for (n = 0; n < len; n++)
 801                                         if (cp[n] == ',')
 802                                                 cp[n] = '\n';
 803                         } else if (strcmp(optarg, "help") == 0) {
 804                                 cp = xstrdup(
 805                                     "cipher\ncipher-auth\ncompression\nkex\n"
 806                                     "key\nkey-cert\nkey-plain\nkey-sig\nmac\n"
 807                                     "protocol-version\nsig");
 808                         }
 809                         if (cp == NULL)
 810                                 fatal("Unsupported query \"%s\"", optarg);
 811                         printf("%s\n", cp);
 812                         free(cp);
 813                         exit(0);
 814                         break;
 815                 case 'a':
 816                         options.forward_agent = 0;
 817                         break;
 818                 case 'A':
 819                         options.forward_agent = 1;
 820                         break;
 821                 case 'k':
 822                         options.gss_deleg_creds = 0;
 823                         break;
 824                 case 'K':
 825                         options.gss_authentication = 1;
 826                         options.gss_deleg_creds = 1;
 827                         break;
 828                 case 'i':
 829                         p = tilde_expand_filename(optarg, getuid());
 830                         if (stat(p, &st) == -1)
 831                                 fprintf(stderr, "Warning: Identity file %s "
 832                                     "not accessible: %s.\n", p,
 833                                     strerror(errno));
 834                         else
 835                                 add_identity_file(&options, NULL, p, 1);
 836                         free(p);
 837                         break;
 838                 case 'I':
 839 #ifdef ENABLE_PKCS11
 840                         free(options.pkcs11_provider);
 841                         options.pkcs11_provider = xstrdup(optarg);
 842 #else
 843                         fprintf(stderr, "no support for PKCS#11.\n");
 844 #endif
 845                         break;
 846                 case 'J':
 847                         if (options.jump_host != NULL) {
 848                                 fatal("Only a single -J option is permitted "
 849                                     "(use commas to separate multiple "
 850                                     "jump hops)");
 851                         }
 852                         if (options.proxy_command != NULL)
 853                                 fatal("Cannot specify -J with ProxyCommand");
 854                         if (parse_jump(optarg, &options, 1) == -1)
 855                                 fatal("Invalid -J argument");
 856                         options.proxy_command = xstrdup("none");
 857                         break;
 858                 case 't':
 859                         if (options.request_tty == REQUEST_TTY_YES)
 860                                 options.request_tty = REQUEST_TTY_FORCE;
 861                         else
 862                                 options.request_tty = REQUEST_TTY_YES;
 863                         break;
 864                 case 'v':
 865                         if (debug_flag == 0) {
 866                                 debug_flag = 1;
 867                                 options.log_level = SYSLOG_LEVEL_DEBUG1;
 868                         } else {
 869                                 if (options.log_level < SYSLOG_LEVEL_DEBUG3) {
 870                                         debug_flag++;
 871                                         options.log_level++;
 872                                 }
 873                         }
 874                         break;
 875                 case 'V':
 876                         if (options.version_addendum &&
 877                             *options.version_addendum != '\0')
 878                                 fprintf(stderr, "%s %s, %s\n", SSH_RELEASE,
 879                                     options.version_addendum,
 880                                     OPENSSL_VERSION_STRING);
 881                         else
 882                                 fprintf(stderr, "%s, %s\n", SSH_RELEASE,
 883                                     OPENSSL_VERSION_STRING);
 884                         if (opt == 'V')
 885                                 exit(0);
 886                         break;
 887                 case 'w':
 888                         if (options.tun_open == -1)
 889                                 options.tun_open = SSH_TUNMODE_DEFAULT;
 890                         options.tun_local = a2tun(optarg, &options.tun_remote);
 891                         if (options.tun_local == SSH_TUNID_ERR) {
 892                                 fprintf(stderr,
 893                                     "Bad tun device '%s'\n", optarg);
 894                                 exit(255);
 895                         }
 896                         break;
 897                 case 'W':
 898                         if (options.stdio_forward_host != NULL)
 899                                 fatal("stdio forward already specified");
 900                         if (muxclient_command != 0)
 901                                 fatal("Cannot specify stdio forward with -O");
 902                         if (parse_forward(&fwd, optarg, 1, 0)) {
 903                                 options.stdio_forward_host = fwd.listen_host;
 904                                 options.stdio_forward_port = fwd.listen_port;
 905                                 free(fwd.connect_host);
 906                         } else {
 907                                 fprintf(stderr,
 908                                     "Bad stdio forwarding specification '%s'\n",
 909                                     optarg);
 910                                 exit(255);
 911                         }
 912                         options.request_tty = REQUEST_TTY_NO;
 913                         options.session_type = SESSION_TYPE_NONE;
 914                         break;
 915                 case 'q':
 916                         options.log_level = SYSLOG_LEVEL_QUIET;
 917                         break;
 918                 case 'e':
 919                         if (optarg[0] == '^' && optarg[2] == 0 &&
 920                             (u_char) optarg[1] >= 64 &&
 921                             (u_char) optarg[1] < 128)
 922                                 options.escape_char = (u_char) optarg[1] & 31;
 923                         else if (strlen(optarg) == 1)
 924                                 options.escape_char = (u_char) optarg[0];
 925                         else if (strcmp(optarg, "none") == 0)
 926                                 options.escape_char = SSH_ESCAPECHAR_NONE;
 927                         else {
 928                                 fprintf(stderr, "Bad escape character '%s'.\n",
 929                                     optarg);
 930                                 exit(255);
 931                         }
 932                         break;
 933                 case 'c':
 934                         if (!ciphers_valid(*optarg == '+' || *optarg == '^' ?
 935                             optarg + 1 : optarg)) {
 936                                 fprintf(stderr, "Unknown cipher type '%s'\n",
 937                                     optarg);
 938                                 exit(255);
 939                         }
 940                         free(options.ciphers);
 941                         options.ciphers = xstrdup(optarg);
 942                         break;
 943                 case 'm':
 944                         if (mac_valid(optarg)) {
 945                                 free(options.macs);
 946                                 options.macs = xstrdup(optarg);
 947                         } else {
 948                                 fprintf(stderr, "Unknown mac type '%s'\n",
 949                                     optarg);
 950                                 exit(255);
 951                         }
 952                         break;
 953                 case 'M':
 954                         if (options.control_master == SSHCTL_MASTER_YES)
 955                                 options.control_master = SSHCTL_MASTER_ASK;
 956                         else
 957                                 options.control_master = SSHCTL_MASTER_YES;
 958                         break;
 959                 case 'p':
 960                         if (options.port == -1) {
 961                                 options.port = a2port(optarg);
 962                                 if (options.port <= 0) {
 963                                         fprintf(stderr, "Bad port '%s'\n",
 964                                             optarg);
 965                                         exit(255);
 966                                 }
 967                         }
 968                         break;
 969                 case 'l':
 970                         if (options.user == NULL)
 971                                 options.user = optarg;
 972                         break;
 973
 974                 case 'L':
 975                         if (parse_forward(&fwd, optarg, 0, 0))
 976                                 add_local_forward(&options, &fwd);
 977                         else {
 978                                 fprintf(stderr,
 979                                     "Bad local forwarding specification '%s'\n",
 980                                     optarg);
 981                                 exit(255);
 982                         }
 983                         break;
 984
 985                 case 'R':
 986                         if (parse_forward(&fwd, optarg, 0, 1) ||
 987                             parse_forward(&fwd, optarg, 1, 1)) {
 988                                 add_remote_forward(&options, &fwd);
 989                         } else {
 990                                 fprintf(stderr,
 991                                     "Bad remote forwarding specification "
 992                                     "'%s'\n", optarg);
 993                                 exit(255);
 994                         }
 995                         break;
 996
 997                 case 'D':
 998                         if (parse_forward(&fwd, optarg, 1, 0)) {
 999                                 add_local_forward(&options, &fwd);
1000                         } else {
1001                                 fprintf(stderr,
1002                                     "Bad dynamic forwarding specification "
1003                                     "'%s'\n", optarg);
1004                                 exit(255);
1005                         }
1006                         break;
1007
1008                 case 'C':
1009 #ifdef WITH_ZLIB
1010                         options.compression = 1;
1011 #else
1012                         error("Compression not supported, disabling.");
1013 #endif
1014                         break;
1015                 case 'N':
1016                         if (options.session_type != -1 &&
1017                             options.session_type != SESSION_TYPE_NONE)
1018                                 fatal("Cannot specify -N with -s/SessionType");
1019                         options.session_type = SESSION_TYPE_NONE;
1020                         options.request_tty = REQUEST_TTY_NO;
1021                         break;
1022                 case 'T':
1023                         options.request_tty = REQUEST_TTY_NO;
1024                         break;
1025                 case 'o':
1026                         line = xstrdup(optarg);
1027                         if (process_config_line(&options, pw,
1028                             host ? host : "", host ? host : "", line,
1029                             "command-line", 0, NULL, SSHCONF_USERCONF) != 0)
1030                                 exit(255);
1031                         free(line);
1032                         break;
1033                 case 's':
1034                         if (options.session_type != -1 &&
1035                             options.session_type != SESSION_TYPE_SUBSYSTEM)
1036                                 fatal("Cannot specify -s with -N/SessionType");
1037                         options.session_type = SESSION_TYPE_SUBSYSTEM;
1038                         break;
1039                 case 'S':
1040                         free(options.control_path);
1041                         options.control_path = xstrdup(optarg);
1042                         break;
1043                 case 'b':
1044                         options.bind_address = optarg;
1045                         break;
1046                 case 'B':
1047                         options.bind_interface = optarg;
1048                         break;
1049                 case 'F':
1050                         config = optarg;
1051                         break;
1052                 default:
1053                         usage();
1054                 }
1055         }
1056
1057         if (optind > 1 && strcmp(av[optind - 1], "--") == 0)
1058                 opt_terminated = 1;
1059
1060         ac -= optind;
1061         av += optind;
1062
1063         if (ac > 0 && !host) {
1064                 int tport;
1065                 char *tuser;
1066                 switch (parse_ssh_uri(*av, &tuser, &host, &tport)) {
1067                 case -1:
1068                         usage();
1069                         break;
1070                 case 0:
1071                         if (options.user == NULL) {
1072                                 options.user = tuser;
1073                                 tuser = NULL;
1074                         }
1075                         free(tuser);
1076                         if (options.port == -1 && tport != -1)
1077                                 options.port = tport;
1078                         break;
1079                 default:
1080                         p = xstrdup(*av);
1081                         cp = strrchr(p, '@');
1082                         if (cp != NULL) {
1083                                 if (cp == p)
1084                                         usage();
1085                                 if (options.user == NULL) {
1086                                         options.user = p;
1087                                         p = NULL;
1088                                 }
1089                                 *cp++ = '\0';
1090                                 host = xstrdup(cp);
1091                                 free(p);
1092                         } else
1093                                 host = p;
1094                         break;
1095                 }
1096                 if (ac > 1 && !opt_terminated) {
1097                         optind = optreset = 1;
1098                         goto again;
1099                 }
1100                 ac--, av++;
1101         }
1102
1103         /* Check that we got a host name. */
1104         if (!host)
1105                 usage();
1106
1107         host_arg = xstrdup(host);
1108
1109         /* Initialize the command to execute on remote host. */
1110         if ((command = sshbuf_new()) == NULL)
1111                 fatal("sshbuf_new failed");
1112
1113         /*
1114          * Save the command to execute on the remote host in a buffer. There
1115          * is no limit on the length of the command, except by the maximum
1116          * packet size.  Also sets the tty flag if there is no command.
1117          */
1118         if (!ac) {
1119                 /* No command specified - execute shell on a tty. */
1120                 if (options.session_type == SESSION_TYPE_SUBSYSTEM) {
1121                         fprintf(stderr,
1122                             "You must specify a subsystem to invoke.\n");
1123                         usage();
1124                 }
1125         } else {
1126                 /* A command has been specified.  Store it into the buffer. */
1127                 for (i = 0; i < ac; i++) {
1128                         if ((r = sshbuf_putf(command, "%s%s",
1129                             i ? " " : "", av[i])) != 0)
1130                                 fatal_fr(r, "buffer error");
1131                 }
1132         }
1133
1134         /*
1135          * Initialize "log" output.  Since we are the client all output
1136          * goes to stderr unless otherwise specified by -y or -E.
1137          */
1138         if (use_syslog && logfile != NULL)
1139                 fatal("Can't specify both -y and -E");
1140         if (logfile != NULL)
1141                 log_redirect_stderr_to(logfile);
1142         log_init(argv0,
1143             options.log_level == SYSLOG_LEVEL_NOT_SET ?
1144             SYSLOG_LEVEL_INFO : options.log_level,
1145             options.log_facility == SYSLOG_FACILITY_NOT_SET ?
1146             SYSLOG_FACILITY_USER : options.log_facility,
1147             !use_syslog);
1148
1149         if (debug_flag)
1150                 /* version_addendum is always NULL at this point */
1151                 logit("%s, %s", SSH_RELEASE, OPENSSL_VERSION_STRING);
1152
1153         /* Parse the configuration files */
1154         process_config_files(host_arg, pw, 0, &want_final_pass);
1155         if (want_final_pass)
1156                 debug("configuration requests final Match pass");
1157
1158         /* Hostname canonicalisation needs a few options filled. */
1159         fill_default_options_for_canonicalization(&options);
1160
1161         /* If the user has replaced the hostname then take it into use now */
1162         if (options.hostname != NULL) {
1163                 /* NB. Please keep in sync with readconf.c:match_cfg_line() */
1164                 cp = percent_expand(options.hostname,
1165                     "h", host, (char *)NULL);
1166                 free(host);
1167                 host = cp;
1168                 free(options.hostname);
1169                 options.hostname = xstrdup(host);
1170         }
1171
1172         /* Don't lowercase addresses, they will be explicitly canonicalised */
1173         if ((was_addr = is_addr(host)) == 0)
1174                 lowercase(host);
1175
1176         /*
1177          * Try to canonicalize if requested by configuration or the
1178          * hostname is an address.
1179          */
1180         if (options.canonicalize_hostname != SSH_CANONICALISE_NO || was_addr)
1181                 addrs = resolve_canonicalize(&host, options.port);
1182
1183         /*
1184          * If CanonicalizePermittedCNAMEs have been specified but
1185          * other canonicalization did not happen (by not being requested
1186          * or by failing with fallback) then the hostname may still be changed
1187          * as a result of CNAME following.
1188          *
1189          * Try to resolve the bare hostname name using the system resolver's
1190          * usual search rules and then apply the CNAME follow rules.
1191          *
1192          * Skip the lookup if a ProxyCommand is being used unless the user
1193          * has specifically requested canonicalisation for this case via
1194          * CanonicalizeHostname=always
1195          */
1196         direct = option_clear_or_none(options.proxy_command) &&
1197             options.jump_host == NULL;
1198         if (addrs == NULL && config_has_permitted_cnames(&options) && (direct ||
1199             options.canonicalize_hostname == SSH_CANONICALISE_ALWAYS)) {
1200                 if ((addrs = resolve_host(host, options.port,
1201                     direct, cname, sizeof(cname))) == NULL) {
1202                         /* Don't fatal proxied host names not in the DNS */
1203                         if (direct)
1204                                 cleanup_exit(255); /* logged in resolve_host */
1205                 } else
1206                         check_follow_cname(direct, &host, cname);
1207         }
1208
1209         /*
1210          * If canonicalisation is enabled then re-parse the configuration
1211          * files as new stanzas may match.
1212          */
1213         if (options.canonicalize_hostname != 0 && !want_final_pass) {
1214                 debug("hostname canonicalisation enabled, "
1215                     "will re-parse configuration");
1216                 want_final_pass = 1;
1217         }
1218
1219         if (want_final_pass) {
1220                 debug("re-parsing configuration");
1221                 free(options.hostname);
1222                 options.hostname = xstrdup(host);
1223                 process_config_files(host_arg, pw, 1, NULL);
1224                 /*
1225                  * Address resolution happens early with canonicalisation
1226                  * enabled and the port number may have changed since, so
1227                  * reset it in address list
1228                  */
1229                 if (addrs != NULL && options.port > 0)
1230                         set_addrinfo_port(addrs, options.port);
1231         }
1232
1233         /* Fill configuration defaults. */
1234         if (fill_default_options(&options) != 0)
1235                 cleanup_exit(255);
1236
1237         if (options.user == NULL)
1238                 options.user = xstrdup(pw->pw_name);
1239
1240         /*
1241          * If ProxyJump option specified, then construct a ProxyCommand now.
1242          */
1243         if (options.jump_host != NULL) {
1244                 char port_s[8];
1245                 const char *jumpuser = options.jump_user, *sshbin = argv0;
1246                 int port = options.port, jumpport = options.jump_port;
1247
1248                 if (port <= 0)
1249                         port = default_ssh_port();
1250                 if (jumpport <= 0)
1251                         jumpport = default_ssh_port();
1252                 if (jumpuser == NULL)
1253                         jumpuser = options.user;
1254                 if (strcmp(options.jump_host, host) == 0 && port == jumpport &&
1255                     strcmp(options.user, jumpuser) == 0)
1256                         fatal("jumphost loop via %s", options.jump_host);
1257
1258                 /*
1259                  * Try to use SSH indicated by argv[0], but fall back to
1260                  * "ssh" if it appears unavailable.
1261                  */
1262                 if (strchr(argv0, '/') != NULL && access(argv0, X_OK) != 0)
1263                         sshbin = "ssh";
1264
1265                 /* Consistency check */
1266                 if (options.proxy_command != NULL)
1267                         fatal("inconsistent options: ProxyCommand+ProxyJump");
1268                 /* Never use FD passing for ProxyJump */
1269                 options.proxy_use_fdpass = 0;
1270                 snprintf(port_s, sizeof(port_s), "%d", options.jump_port);
1271                 xasprintf(&options.proxy_command,
1272                     "%s%s%s%s%s%s%s%s%s%s%.*s -W '[%%h]:%%p' %s",
1273                     sshbin,
1274                     /* Optional "-l user" argument if jump_user set */
1275                     options.jump_user == NULL ? "" : " -l ",
1276                     options.jump_user == NULL ? "" : options.jump_user,
1277                     /* Optional "-p port" argument if jump_port set */
1278                     options.jump_port <= 0 ? "" : " -p ",
1279                     options.jump_port <= 0 ? "" : port_s,
1280                     /* Optional additional jump hosts ",..." */
1281                     options.jump_extra == NULL ? "" : " -J ",
1282                     options.jump_extra == NULL ? "" : options.jump_extra,
1283                     /* Optional "-F" argumment if -F specified */
1284                     config == NULL ? "" : " -F ",
1285                     config == NULL ? "" : config,
1286                     /* Optional "-v" arguments if -v set */
1287                     debug_flag ? " -" : "",
1288                     debug_flag, "vvv",
1289                     /* Mandatory hostname */
1290                     options.jump_host);
1291                 debug("Setting implicit ProxyCommand from ProxyJump: %s",
1292                     options.proxy_command);
1293         }
1294
1295         if (options.port == 0)
1296                 options.port = default_ssh_port();
1297         channel_set_af(ssh, options.address_family);
1298
1299         /* Tidy and check options */
1300         if (options.host_key_alias != NULL)
1301                 lowercase(options.host_key_alias);
1302         if (options.proxy_command != NULL &&
1303             strcmp(options.proxy_command, "-") == 0 &&
1304             options.proxy_use_fdpass)
1305                 fatal("ProxyCommand=- and ProxyUseFDPass are incompatible");
1306         if (options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK) {
1307                 if (options.control_persist && options.control_path != NULL) {
1308                         debug("UpdateHostKeys=ask is incompatible with "
1309                             "ControlPersist; disabling");
1310                         options.update_hostkeys = 0;
1311                 } else if (sshbuf_len(command) != 0 ||
1312                     options.remote_command != NULL ||
1313                     options.request_tty == REQUEST_TTY_NO) {
1314                         debug("UpdateHostKeys=ask is incompatible with "
1315                             "remote command execution; disabling");
1316                         options.update_hostkeys = 0;
1317                 } else if (options.log_level < SYSLOG_LEVEL_INFO) {
1318                         /* no point logging anything; user won't see it */
1319                         options.update_hostkeys = 0;
1320                 }
1321         }
1322         if (options.connection_attempts <= 0)
1323                 fatal("Invalid number of ConnectionAttempts");
1324
1325         if (sshbuf_len(command) != 0 && options.remote_command != NULL)
1326                 fatal("Cannot execute command-line and remote command.");
1327
1328         /* Cannot fork to background if no command. */
1329         if (options.fork_after_authentication && sshbuf_len(command) == 0 &&
1330             options.remote_command == NULL &&
1331             options.session_type != SESSION_TYPE_NONE)
1332                 fatal("Cannot fork into background without a command "
1333                     "to execute.");
1334
1335         /* reinit */
1336         log_init(argv0, options.log_level, options.log_facility, !use_syslog);
1337         for (j = 0; j < options.num_log_verbose; j++) {
1338                 if (strcasecmp(options.log_verbose[j], "none") == 0)
1339                         break;
1340                 log_verbose_add(options.log_verbose[j]);
1341         }
1342
1343         if (options.request_tty == REQUEST_TTY_YES ||
1344             options.request_tty == REQUEST_TTY_FORCE)
1345                 tty_flag = 1;
1346
1347         /* Allocate a tty by default if no command specified. */
1348         if (sshbuf_len(command) == 0 && options.remote_command == NULL)
1349                 tty_flag = options.request_tty != REQUEST_TTY_NO;
1350
1351         /* Force no tty */
1352         if (options.request_tty == REQUEST_TTY_NO ||
1353             (muxclient_command && muxclient_command != SSHMUX_COMMAND_PROXY))
1354                 tty_flag = 0;
1355         /* Do not allocate a tty if stdin is not a tty. */
1356         if ((!isatty(fileno(stdin)) || options.stdin_null) &&
1357             options.request_tty != REQUEST_TTY_FORCE) {
1358                 if (tty_flag)
1359                         logit("Pseudo-terminal will not be allocated because "
1360                             "stdin is not a terminal.");
1361                 tty_flag = 0;
1362         }
1363
1364         /* Set up strings used to percent_expand() arguments */
1365         cinfo = xcalloc(1, sizeof(*cinfo));
1366         if (gethostname(thishost, sizeof(thishost)) == -1)
1367                 fatal("gethostname: %s", strerror(errno));
1368         cinfo->thishost = xstrdup(thishost);
1369         thishost[strcspn(thishost, ".")] = '\0';
1370         cinfo->shorthost = xstrdup(thishost);
1371         xasprintf(&cinfo->portstr, "%d", options.port);
1372         xasprintf(&cinfo->uidstr, "%llu",
1373             (unsigned long long)pw->pw_uid);
1374         cinfo->keyalias = xstrdup(options.host_key_alias ?
1375             options.host_key_alias : host_arg);
1376         cinfo->conn_hash_hex = ssh_connection_hash(cinfo->thishost, host,
1377             cinfo->portstr, options.user);
1378         cinfo->host_arg = xstrdup(host_arg);
1379         cinfo->remhost = xstrdup(host);
1380         cinfo->remuser = xstrdup(options.user);
1381         cinfo->homedir = xstrdup(pw->pw_dir);
1382         cinfo->locuser = xstrdup(pw->pw_name);
1383
1384         /* Find canonic host name. */
1385         if (strchr(host, '.') == 0) {
1386                 struct addrinfo hints;
1387                 struct addrinfo *ai = NULL;
1388                 int errgai;
1389                 memset(&hints, 0, sizeof(hints));
1390                 hints.ai_family = options.address_family;
1391                 hints.ai_flags = AI_CANONNAME;
1392                 hints.ai_socktype = SOCK_STREAM;
1393                 errgai = getaddrinfo(host, NULL, &hints, &ai);
1394                 if (errgai == 0) {
1395                         if (ai->ai_canonname != NULL)
1396                                 host = xstrdup(ai->ai_canonname);
1397                         freeaddrinfo(ai);
1398                 }
1399         }
1400
1401         /*
1402          * Expand tokens in arguments. NB. LocalCommand is expanded later,
1403          * after port-forwarding is set up, so it may pick up any local
1404          * tunnel interface name allocated.
1405          */
1406         if (options.remote_command != NULL) {
1407                 debug3("expanding RemoteCommand: %s", options.remote_command);
1408                 cp = options.remote_command;
1409                 options.remote_command = default_client_percent_expand(cp,
1410                     cinfo);
1411                 debug3("expanded RemoteCommand: %s", options.remote_command);
1412                 free(cp);
1413                 if ((r = sshbuf_put(command, options.remote_command,
1414                     strlen(options.remote_command))) != 0)
1415                         fatal_fr(r, "buffer error");
1416         }
1417
1418         if (options.control_path != NULL) {
1419                 cp = tilde_expand_filename(options.control_path, getuid());
1420                 free(options.control_path);
1421                 options.control_path = default_client_percent_dollar_expand(cp,
1422                     cinfo);
1423                 free(cp);
1424         }
1425
1426         if (options.identity_agent != NULL) {
1427                 p = tilde_expand_filename(options.identity_agent, getuid());
1428                 cp = default_client_percent_dollar_expand(p, cinfo);
1429                 free(p);
1430                 free(options.identity_agent);
1431                 options.identity_agent = cp;
1432         }
1433
1434         if (options.forward_agent_sock_path != NULL) {
1435                 p = tilde_expand_filename(options.forward_agent_sock_path,
1436                     getuid());
1437                 cp = default_client_percent_dollar_expand(p, cinfo);
1438                 free(p);
1439                 free(options.forward_agent_sock_path);
1440                 options.forward_agent_sock_path = cp;
1441                 if (stat(options.forward_agent_sock_path, &st) != 0) {
1442                         error("Cannot forward agent socket path \"%s\": %s",
1443                             options.forward_agent_sock_path, strerror(errno));
1444                         if (options.exit_on_forward_failure)
1445                                 cleanup_exit(255);
1446                 }
1447         }
1448
1449         if (options.num_system_hostfiles > 0 &&
1450             strcasecmp(options.system_hostfiles[0], "none") == 0) {
1451                 if (options.num_system_hostfiles > 1)
1452                         fatal("Invalid GlobalKnownHostsFiles: \"none\" "
1453                             "appears with other entries");
1454                 free(options.system_hostfiles[0]);
1455                 options.system_hostfiles[0] = NULL;
1456                 options.num_system_hostfiles = 0;
1457         }
1458
1459         if (options.num_user_hostfiles > 0 &&
1460             strcasecmp(options.user_hostfiles[0], "none") == 0) {
1461                 if (options.num_user_hostfiles > 1)
1462                         fatal("Invalid UserKnownHostsFiles: \"none\" "
1463                             "appears with other entries");
1464                 free(options.user_hostfiles[0]);
1465                 options.user_hostfiles[0] = NULL;
1466                 options.num_user_hostfiles = 0;
1467         }
1468         for (j = 0; j < options.num_user_hostfiles; j++) {
1469                 if (options.user_hostfiles[j] == NULL)
1470                         continue;
1471                 cp = tilde_expand_filename(options.user_hostfiles[j], getuid());
1472                 p = default_client_percent_dollar_expand(cp, cinfo);
1473                 if (strcmp(options.user_hostfiles[j], p) != 0)
1474                         debug3("expanded UserKnownHostsFile '%s' -> "
1475                             "'%s'", options.user_hostfiles[j], p);
1476                 free(options.user_hostfiles[j]);
1477                 free(cp);
1478                 options.user_hostfiles[j] = p;
1479         }
1480
1481         for (i = 0; i < options.num_local_forwards; i++) {
1482                 if (options.local_forwards[i].listen_path != NULL) {
1483                         cp = options.local_forwards[i].listen_path;
1484                         p = options.local_forwards[i].listen_path =
1485                             default_client_percent_expand(cp, cinfo);
1486                         if (strcmp(cp, p) != 0)
1487                                 debug3("expanded LocalForward listen path "
1488                                     "'%s' -> '%s'", cp, p);
1489                         free(cp);
1490                 }
1491                 if (options.local_forwards[i].connect_path != NULL) {
1492                         cp = options.local_forwards[i].connect_path;
1493                         p = options.local_forwards[i].connect_path =
1494                             default_client_percent_expand(cp, cinfo);
1495                         if (strcmp(cp, p) != 0)
1496                                 debug3("expanded LocalForward connect path "
1497                                     "'%s' -> '%s'", cp, p);
1498                         free(cp);
1499                 }
1500         }
1501
1502         for (i = 0; i < options.num_remote_forwards; i++) {
1503                 if (options.remote_forwards[i].listen_path != NULL) {
1504                         cp = options.remote_forwards[i].listen_path;
1505                         p = options.remote_forwards[i].listen_path =
1506                             default_client_percent_expand(cp, cinfo);
1507                         if (strcmp(cp, p) != 0)
1508                                 debug3("expanded RemoteForward listen path "
1509                                     "'%s' -> '%s'", cp, p);
1510                         free(cp);
1511                 }
1512                 if (options.remote_forwards[i].connect_path != NULL) {
1513                         cp = options.remote_forwards[i].connect_path;
1514                         p = options.remote_forwards[i].connect_path =
1515                             default_client_percent_expand(cp, cinfo);
1516                         if (strcmp(cp, p) != 0)
1517                                 debug3("expanded RemoteForward connect path "
1518                                     "'%s' -> '%s'", cp, p);
1519                         free(cp);
1520                 }
1521         }
1522
1523         if (config_test) {
1524                 dump_client_config(&options, host);
1525                 exit(0);
1526         }
1527
1528         /* Expand SecurityKeyProvider if it refers to an environment variable */
1529         if (options.sk_provider != NULL && *options.sk_provider == '$' &&
1530             strlen(options.sk_provider) > 1) {
1531                 if ((cp = getenv(options.sk_provider + 1)) == NULL) {
1532                         debug("Authenticator provider %s did not resolve; "
1533                             "disabling", options.sk_provider);
1534                         free(options.sk_provider);
1535                         options.sk_provider = NULL;
1536                 } else {
1537                         debug2("resolved SecurityKeyProvider %s => %s",
1538                             options.sk_provider, cp);
1539                         free(options.sk_provider);
1540                         options.sk_provider = xstrdup(cp);
1541                 }
1542         }
1543
1544         if (muxclient_command != 0 && options.control_path == NULL)
1545                 fatal("No ControlPath specified for \"-O\" command");
1546         if (options.control_path != NULL) {
1547                 int sock;
1548                 if ((sock = muxclient(options.control_path)) >= 0) {
1549                         ssh_packet_set_connection(ssh, sock, sock);
1550                         ssh_packet_set_mux(ssh);
1551                         goto skip_connect;
1552                 }
1553         }
1554
1555         /*
1556          * If hostname canonicalisation was not enabled, then we may not
1557          * have yet resolved the hostname. Do so now.
1558          */
1559         if (addrs == NULL && options.proxy_command == NULL) {
1560                 debug2("resolving \"%s\" port %d", host, options.port);
1561                 if ((addrs = resolve_host(host, options.port, 1,
1562                     cname, sizeof(cname))) == NULL)
1563                         cleanup_exit(255); /* resolve_host logs the error */
1564         }
1565
1566         if (options.connection_timeout >= INT_MAX/1000)
1567                 timeout_ms = INT_MAX;
1568         else
1569                 timeout_ms = options.connection_timeout * 1000;
1570
1571         /* Open a connection to the remote host. */
1572         if (ssh_connect(ssh, host, host_arg, addrs, &hostaddr, options.port,
1573             options.connection_attempts,
1574             &timeout_ms, options.tcp_keep_alive) != 0)
1575                 exit(255);
1576
1577         if (addrs != NULL)
1578                 freeaddrinfo(addrs);
1579
1580         ssh_packet_set_timeout(ssh, options.server_alive_interval,
1581             options.server_alive_count_max);
1582
1583         if (timeout_ms > 0)
1584                 debug3("timeout: %d ms remain after connect", timeout_ms);
1585
1586         /*
1587          * If we successfully made the connection and we have hostbased auth
1588          * enabled, load the public keys so we can later use the ssh-keysign
1589          * helper to sign challenges.
1590          */
1591         sensitive_data.nkeys = 0;
1592         sensitive_data.keys = NULL;
1593         if (options.hostbased_authentication) {
1594                 sensitive_data.nkeys = 10;
1595                 sensitive_data.keys = xcalloc(sensitive_data.nkeys,
1596                     sizeof(struct sshkey));
1597
1598                 /* XXX check errors? */
1599 #define L_PUBKEY(p,o) do { \
1600         if ((o) >= sensitive_data.nkeys) \
1601                 fatal_f("pubkey out of array bounds"); \
1602         check_load(sshkey_load_public(p, &(sensitive_data.keys[o]), NULL), \
1603             p, "pubkey"); \
1604 } while (0)
1605 #define L_CERT(p,o) do { \
1606         if ((o) >= sensitive_data.nkeys) \
1607                 fatal_f("cert out of array bounds"); \
1608         check_load(sshkey_load_cert(p, &(sensitive_data.keys[o])), p, "cert"); \
1609 } while (0)
1610
1611                 if (options.hostbased_authentication == 1) {
1612                         L_CERT(_PATH_HOST_ECDSA_KEY_FILE, 0);
1613                         L_CERT(_PATH_HOST_ED25519_KEY_FILE, 1);
1614                         L_CERT(_PATH_HOST_RSA_KEY_FILE, 2);
1615                         L_CERT(_PATH_HOST_DSA_KEY_FILE, 3);
1616                         L_PUBKEY(_PATH_HOST_ECDSA_KEY_FILE, 4);
1617                         L_PUBKEY(_PATH_HOST_ED25519_KEY_FILE, 5);
1618                         L_PUBKEY(_PATH_HOST_RSA_KEY_FILE, 6);
1619                         L_PUBKEY(_PATH_HOST_DSA_KEY_FILE, 7);
1620                         L_CERT(_PATH_HOST_XMSS_KEY_FILE, 8);
1621                         L_PUBKEY(_PATH_HOST_XMSS_KEY_FILE, 9);
1622                 }
1623         }
1624
1625         /* load options.identity_files */
1626         load_public_identity_files(cinfo);
1627
1628         /* optionally set the SSH_AUTHSOCKET_ENV_NAME variable */
1629         if (options.identity_agent &&
1630             strcmp(options.identity_agent, SSH_AUTHSOCKET_ENV_NAME) != 0) {
1631                 if (strcmp(options.identity_agent, "none") == 0) {
1632                         unsetenv(SSH_AUTHSOCKET_ENV_NAME);
1633                 } else {
1634                         cp = options.identity_agent;
1635                         /* legacy (limited) format */
1636                         if (cp[0] == '$' && cp[1] != '{') {
1637                                 if (!valid_env_name(cp + 1)) {
1638                                         fatal("Invalid IdentityAgent "
1639                                             "environment variable name %s", cp);
1640                                 }
1641                                 if ((p = getenv(cp + 1)) == NULL)
1642                                         unsetenv(SSH_AUTHSOCKET_ENV_NAME);
1643                                 else
1644                                         setenv(SSH_AUTHSOCKET_ENV_NAME, p, 1);
1645                         } else {
1646                                 /* identity_agent specifies a path directly */
1647                                 setenv(SSH_AUTHSOCKET_ENV_NAME, cp, 1);
1648                         }
1649                 }
1650         }
1651
1652         if (options.forward_agent && options.forward_agent_sock_path != NULL) {
1653                 cp = options.forward_agent_sock_path;
1654                 if (cp[0] == '$') {
1655                         if (!valid_env_name(cp + 1)) {
1656                                 fatal("Invalid ForwardAgent environment variable name %s", cp);
1657                         }
1658                         if ((p = getenv(cp + 1)) != NULL)
1659                                 forward_agent_sock_path = xstrdup(p);
1660                         else
1661                                 options.forward_agent = 0;
1662                         free(cp);
1663                 } else {
1664                         forward_agent_sock_path = cp;
1665                 }
1666         }
1667
1668         /* Expand ~ in known host file names. */
1669         tilde_expand_paths(options.system_hostfiles,
1670             options.num_system_hostfiles);
1671         tilde_expand_paths(options.user_hostfiles, options.num_user_hostfiles);
1672
1673         ssh_signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */
1674         ssh_signal(SIGCHLD, main_sigchld_handler);
1675
1676         /* Log into the remote system.  Never returns if the login fails. */
1677         ssh_login(ssh, &sensitive_data, host, (struct sockaddr *)&hostaddr,
1678             options.port, pw, timeout_ms, cinfo);
1679
1680         /* We no longer need the private host keys.  Clear them now. */
1681         if (sensitive_data.nkeys != 0) {
1682                 for (i = 0; i < sensitive_data.nkeys; i++) {
1683                         if (sensitive_data.keys[i] != NULL) {
1684                                 /* Destroys contents safely */
1685                                 debug3("clear hostkey %d", i);
1686                                 sshkey_free(sensitive_data.keys[i]);
1687                                 sensitive_data.keys[i] = NULL;
1688                         }
1689                 }
1690                 free(sensitive_data.keys);
1691         }
1692         for (i = 0; i < options.num_identity_files; i++) {
1693                 free(options.identity_files[i]);
1694                 options.identity_files[i] = NULL;
1695                 if (options.identity_keys[i]) {
1696                         sshkey_free(options.identity_keys[i]);
1697                         options.identity_keys[i] = NULL;
1698                 }
1699         }
1700         for (i = 0; i < options.num_certificate_files; i++) {
1701                 free(options.certificate_files[i]);
1702                 options.certificate_files[i] = NULL;
1703         }
1704
1705 #ifdef ENABLE_PKCS11
1706         (void)pkcs11_del_provider(options.pkcs11_provider);
1707 #endif
1708
1709  skip_connect:
1710         exit_status = ssh_session2(ssh, cinfo);
1711         ssh_conn_info_free(cinfo);
1712         ssh_packet_close(ssh);
1713
1714         if (options.control_path != NULL && muxserver_sock != -1)
1715                 unlink(options.control_path);
1716
1717         /* Kill ProxyCommand if it is running. */
1718         ssh_kill_proxy_command();
1719
1720         return exit_status;
1721 }
1722
1723 static void
1724 control_persist_detach(void)
1725 {
1726         pid_t pid;
1727
1728         debug_f("backgrounding master process");
1729
1730         /*
1731          * master (current process) into the background, and make the
1732          * foreground process a client of the backgrounded master.
1733          */
1734         switch ((pid = fork())) {
1735         case -1:
1736                 fatal_f("fork: %s", strerror(errno));
1737         case 0:
1738                 /* Child: master process continues mainloop */
1739                 break;
1740         default:
1741                 /* Parent: set up mux client to connect to backgrounded master */
1742                 debug2_f("background process is %ld", (long)pid);
1743                 options.stdin_null = ostdin_null_flag;
1744                 options.request_tty = orequest_tty;
1745                 tty_flag = otty_flag;
1746                 options.session_type = osession_type;
1747                 close(muxserver_sock);
1748                 muxserver_sock = -1;
1749                 options.control_master = SSHCTL_MASTER_NO;
1750                 muxclient(options.control_path);
1751                 /* muxclient() doesn't return on success. */
1752                 fatal("Failed to connect to new control master");
1753         }
1754         if (stdfd_devnull(1, 1, !(log_is_on_stderr() && debug_flag)) == -1)
1755                 error_f("stdfd_devnull failed");
1756         daemon(1, 1);
1757         setproctitle("%s [mux]", options.control_path);
1758 }
1759
1760 /* Do fork() after authentication. Used by "ssh -f" */
1761 static void
1762 fork_postauth(void)
1763 {
1764         if (need_controlpersist_detach)
1765                 control_persist_detach();
1766         debug("forking to background");
1767         options.fork_after_authentication = 0;
1768         if (daemon(1, 1) == -1)
1769                 fatal("daemon() failed: %.200s", strerror(errno));
1770         if (stdfd_devnull(1, 1, !(log_is_on_stderr() && debug_flag)) == -1)
1771                 error_f("stdfd_devnull failed");
1772 }
1773
1774 static void
1775 forwarding_success(void)
1776 {
1777         if (forward_confirms_pending == -1)
1778                 return;
1779         if (--forward_confirms_pending == 0) {
1780                 debug_f("all expected forwarding replies received");
1781                 if (options.fork_after_authentication)
1782                         fork_postauth();
1783         } else {
1784                 debug2_f("%d expected forwarding replies remaining",
1785                     forward_confirms_pending);
1786         }
1787 }
1788
1789 /* Callback for remote forward global requests */
1790 static void
1791 ssh_confirm_remote_forward(struct ssh *ssh, int type, u_int32_t seq, void *ctxt)
1792 {
1793         struct Forward *rfwd = (struct Forward *)ctxt;
1794         u_int port;
1795         int r;
1796
1797         /* XXX verbose() on failure? */
1798         debug("remote forward %s for: listen %s%s%d, connect %s:%d",
1799             type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure",
1800             rfwd->listen_path ? rfwd->listen_path :
1801             rfwd->listen_host ? rfwd->listen_host : "",
1802             (rfwd->listen_path || rfwd->listen_host) ? ":" : "",
1803             rfwd->listen_port, rfwd->connect_path ? rfwd->connect_path :
1804             rfwd->connect_host, rfwd->connect_port);
1805         if (rfwd->listen_path == NULL && rfwd->listen_port == 0) {
1806                 if (type == SSH2_MSG_REQUEST_SUCCESS) {
1807                         if ((r = sshpkt_get_u32(ssh, &port)) != 0)
1808                                 fatal_fr(r, "parse packet");
1809                         if (port > 65535) {
1810                                 error("Invalid allocated port %u for remote "
1811                                     "forward to %s:%d", port,
1812                                     rfwd->connect_host, rfwd->connect_port);
1813                                 /* Ensure failure processing runs below */
1814                                 type = SSH2_MSG_REQUEST_FAILURE;
1815                                 channel_update_permission(ssh,
1816                                     rfwd->handle, -1);
1817                         } else {
1818                                 rfwd->allocated_port = (int)port;
1819                                 logit("Allocated port %u for remote "
1820                                     "forward to %s:%d",
1821                                     rfwd->allocated_port, rfwd->connect_path ?
1822                                     rfwd->connect_path : rfwd->connect_host,
1823                                     rfwd->connect_port);
1824                                 channel_update_permission(ssh,
1825                                     rfwd->handle, rfwd->allocated_port);
1826                         }
1827                 } else {
1828                         channel_update_permission(ssh, rfwd->handle, -1);
1829                 }
1830         }
1831
1832         if (type == SSH2_MSG_REQUEST_FAILURE) {
1833                 if (options.exit_on_forward_failure) {
1834                         if (rfwd->listen_path != NULL)
1835                                 fatal("Error: remote port forwarding failed "
1836                                     "for listen path %s", rfwd->listen_path);
1837                         else
1838                                 fatal("Error: remote port forwarding failed "
1839                                     "for listen port %d", rfwd->listen_port);
1840                 } else {
1841                         if (rfwd->listen_path != NULL)
1842                                 logit("Warning: remote port forwarding failed "
1843                                     "for listen path %s", rfwd->listen_path);
1844                         else
1845                                 logit("Warning: remote port forwarding failed "
1846                                     "for listen port %d", rfwd->listen_port);
1847                 }
1848         }
1849         forwarding_success();
1850 }
1851
1852 static void
1853 client_cleanup_stdio_fwd(struct ssh *ssh, int id, void *arg)
1854 {
1855         debug("stdio forwarding: done");
1856         cleanup_exit(0);
1857 }
1858
1859 static void
1860 ssh_stdio_confirm(struct ssh *ssh, int id, int success, void *arg)
1861 {
1862         if (!success)
1863                 fatal("stdio forwarding failed");
1864 }
1865
1866 static void
1867 ssh_tun_confirm(struct ssh *ssh, int id, int success, void *arg)
1868 {
1869         if (!success) {
1870                 error("Tunnel forwarding failed");
1871                 if (options.exit_on_forward_failure)
1872                         cleanup_exit(255);
1873         }
1874
1875         debug_f("tunnel forward established, id=%d", id);
1876         forwarding_success();
1877 }
1878
1879 static void
1880 ssh_init_stdio_forwarding(struct ssh *ssh)
1881 {
1882         Channel *c;
1883         int in, out;
1884
1885         if (options.stdio_forward_host == NULL)
1886                 return;
1887
1888         debug3_f("%s:%d", options.stdio_forward_host,
1889             options.stdio_forward_port);
1890
1891         if ((in = dup(STDIN_FILENO)) == -1 ||
1892             (out = dup(STDOUT_FILENO)) == -1)
1893                 fatal_f("dup() in/out failed");
1894         if ((c = channel_connect_stdio_fwd(ssh, options.stdio_forward_host,
1895             options.stdio_forward_port, in, out,
1896             CHANNEL_NONBLOCK_STDIO)) == NULL)
1897                 fatal_f("channel_connect_stdio_fwd failed");
1898         channel_register_cleanup(ssh, c->self, client_cleanup_stdio_fwd, 0);
1899         channel_register_open_confirm(ssh, c->self, ssh_stdio_confirm, NULL);
1900 }
1901
1902 static void
1903 ssh_init_forward_permissions(struct ssh *ssh, const char *what, char **opens,
1904     u_int num_opens)
1905 {
1906         u_int i;
1907         int port;
1908         char *addr, *arg, *oarg, ch;
1909         int where = FORWARD_LOCAL;
1910
1911         channel_clear_permission(ssh, FORWARD_ADM, where);
1912         if (num_opens == 0)
1913                 return; /* permit any */
1914
1915         /* handle keywords: "any" / "none" */
1916         if (num_opens == 1 && strcmp(opens[0], "any") == 0)
1917                 return;
1918         if (num_opens == 1 && strcmp(opens[0], "none") == 0) {
1919                 channel_disable_admin(ssh, where);
1920                 return;
1921         }
1922         /* Otherwise treat it as a list of permitted host:port */
1923         for (i = 0; i < num_opens; i++) {
1924                 oarg = arg = xstrdup(opens[i]);
1925                 ch = '\0';
1926                 addr = hpdelim2(&arg, &ch);
1927                 if (addr == NULL || ch == '/')
1928                         fatal_f("missing host in %s", what);
1929                 addr = cleanhostname(addr);
1930                 if (arg == NULL || ((port = permitopen_port(arg)) < 0))
1931                         fatal_f("bad port number in %s", what);
1932                 /* Send it to channels layer */
1933                 channel_add_permission(ssh, FORWARD_ADM,
1934                     where, addr, port);
1935                 free(oarg);
1936         }
1937 }
1938
1939 static void
1940 ssh_init_forwarding(struct ssh *ssh, char **ifname)
1941 {
1942         int success = 0;
1943         int i;
1944
1945         ssh_init_forward_permissions(ssh, "permitremoteopen",
1946             options.permitted_remote_opens,
1947             options.num_permitted_remote_opens);
1948
1949         if (options.exit_on_forward_failure)
1950                 forward_confirms_pending = 0; /* track pending requests */
1951         /* Initiate local TCP/IP port forwardings. */
1952         for (i = 0; i < options.num_local_forwards; i++) {
1953                 debug("Local connections to %.200s:%d forwarded to remote "
1954                     "address %.200s:%d",
1955                     (options.local_forwards[i].listen_path != NULL) ?
1956                     options.local_forwards[i].listen_path :
1957                     (options.local_forwards[i].listen_host == NULL) ?
1958                     (options.fwd_opts.gateway_ports ? "*" : "LOCALHOST") :
1959                     options.local_forwards[i].listen_host,
1960                     options.local_forwards[i].listen_port,
1961                     (options.local_forwards[i].connect_path != NULL) ?
1962                     options.local_forwards[i].connect_path :
1963                     options.local_forwards[i].connect_host,
1964                     options.local_forwards[i].connect_port);
1965                 success += channel_setup_local_fwd_listener(ssh,
1966                     &options.local_forwards[i], &options.fwd_opts);
1967         }
1968         if (i > 0 && success != i && options.exit_on_forward_failure)
1969                 fatal("Could not request local forwarding.");
1970         if (i > 0 && success == 0)
1971                 error("Could not request local forwarding.");
1972
1973         /* Initiate remote TCP/IP port forwardings. */
1974         for (i = 0; i < options.num_remote_forwards; i++) {
1975                 debug("Remote connections from %.200s:%d forwarded to "
1976                     "local address %.200s:%d",
1977                     (options.remote_forwards[i].listen_path != NULL) ?
1978                     options.remote_forwards[i].listen_path :
1979                     (options.remote_forwards[i].listen_host == NULL) ?
1980                     "LOCALHOST" : options.remote_forwards[i].listen_host,
1981                     options.remote_forwards[i].listen_port,
1982                     (options.remote_forwards[i].connect_path != NULL) ?
1983                     options.remote_forwards[i].connect_path :
1984                     options.remote_forwards[i].connect_host,
1985                     options.remote_forwards[i].connect_port);
1986                 if ((options.remote_forwards[i].handle =
1987                     channel_request_remote_forwarding(ssh,
1988                     &options.remote_forwards[i])) >= 0) {
1989                         client_register_global_confirm(
1990                             ssh_confirm_remote_forward,
1991                             &options.remote_forwards[i]);
1992                         forward_confirms_pending++;
1993                 } else if (options.exit_on_forward_failure)
1994                         fatal("Could not request remote forwarding.");
1995                 else
1996                         logit("Warning: Could not request remote forwarding.");
1997         }
1998
1999         /* Initiate tunnel forwarding. */
2000         if (options.tun_open != SSH_TUNMODE_NO) {
2001                 if ((*ifname = client_request_tun_fwd(ssh,
2002                     options.tun_open, options.tun_local,
2003                     options.tun_remote, ssh_tun_confirm, NULL)) != NULL)
2004                         forward_confirms_pending++;
2005                 else if (options.exit_on_forward_failure)
2006                         fatal("Could not request tunnel forwarding.");
2007                 else
2008                         error("Could not request tunnel forwarding.");
2009         }
2010         if (forward_confirms_pending > 0) {
2011                 debug_f("expecting replies for %d forwards",
2012                     forward_confirms_pending);
2013         }
2014 }
2015
2016 static void
2017 check_agent_present(void)
2018 {
2019         int r;
2020
2021         if (options.forward_agent) {
2022                 /* Clear agent forwarding if we don't have an agent. */
2023                 if ((r = ssh_get_authentication_socket(NULL)) != 0) {
2024                         options.forward_agent = 0;
2025                         if (r != SSH_ERR_AGENT_NOT_PRESENT)
2026                                 debug_r(r, "ssh_get_authentication_socket");
2027                 }
2028         }
2029 }
2030
2031 static void
2032 ssh_session2_setup(struct ssh *ssh, int id, int success, void *arg)
2033 {
2034         extern char **environ;
2035         const char *display, *term;
2036         int r, interactive = tty_flag;
2037         char *proto = NULL, *data = NULL;
2038
2039         if (!success)
2040                 return; /* No need for error message, channels code sens one */
2041
2042         display = getenv("DISPLAY");
2043         if (display == NULL && options.forward_x11)
2044                 debug("X11 forwarding requested but DISPLAY not set");
2045         if (options.forward_x11 && client_x11_get_proto(ssh, display,
2046             options.xauth_location, options.forward_x11_trusted,
2047             options.forward_x11_timeout, &proto, &data) == 0) {
2048                 /* Request forwarding with authentication spoofing. */
2049                 debug("Requesting X11 forwarding with authentication "
2050                     "spoofing.");
2051                 x11_request_forwarding_with_spoofing(ssh, id, display, proto,
2052                     data, 1);
2053                 client_expect_confirm(ssh, id, "X11 forwarding", CONFIRM_WARN);
2054                 /* XXX exit_on_forward_failure */
2055                 interactive = 1;
2056         }
2057
2058         check_agent_present();
2059         if (options.forward_agent) {
2060                 debug("Requesting authentication agent forwarding.");
2061                 channel_request_start(ssh, id, "auth-agent-req@openssh.com", 0);
2062                 if ((r = sshpkt_send(ssh)) != 0)
2063                         fatal_fr(r, "send packet");
2064         }
2065
2066         /* Tell the packet module whether this is an interactive session. */
2067         ssh_packet_set_interactive(ssh, interactive,
2068             options.ip_qos_interactive, options.ip_qos_bulk);
2069
2070         if ((term = lookup_env_in_list("TERM", options.setenv,
2071             options.num_setenv)) == NULL || *term == '\0')
2072                 term = getenv("TERM");
2073         client_session2_setup(ssh, id, tty_flag,
2074             options.session_type == SESSION_TYPE_SUBSYSTEM, term,
2075             NULL, fileno(stdin), command, environ);
2076 }
2077
2078 /* open new channel for a session */
2079 static int
2080 ssh_session2_open(struct ssh *ssh)
2081 {
2082         Channel *c;
2083         int window, packetmax, in, out, err;
2084
2085         if (options.stdin_null) {
2086                 in = open(_PATH_DEVNULL, O_RDONLY);
2087         } else {
2088                 in = dup(STDIN_FILENO);
2089         }
2090         out = dup(STDOUT_FILENO);
2091         err = dup(STDERR_FILENO);
2092
2093         if (in == -1 || out == -1 || err == -1)
2094                 fatal("dup() in/out/err failed");
2095
2096         window = CHAN_SES_WINDOW_DEFAULT;
2097         packetmax = CHAN_SES_PACKET_DEFAULT;
2098         if (tty_flag) {
2099                 window >>= 1;
2100                 packetmax >>= 1;
2101         }
2102         c = channel_new(ssh,
2103             "session", SSH_CHANNEL_OPENING, in, out, err,
2104             window, packetmax, CHAN_EXTENDED_WRITE,
2105             "client-session", CHANNEL_NONBLOCK_STDIO);
2106
2107         debug3_f("channel_new: %d", c->self);
2108
2109         channel_send_open(ssh, c->self);
2110         if (options.session_type != SESSION_TYPE_NONE)
2111                 channel_register_open_confirm(ssh, c->self,
2112                     ssh_session2_setup, NULL);
2113
2114         return c->self;
2115 }
2116
2117 static int
2118 ssh_session2(struct ssh *ssh, const struct ssh_conn_info *cinfo)
2119 {
2120         int r, id = -1;
2121         char *cp, *tun_fwd_ifname = NULL;
2122
2123         /* XXX should be pre-session */
2124         if (!options.control_persist)
2125                 ssh_init_stdio_forwarding(ssh);
2126
2127         ssh_init_forwarding(ssh, &tun_fwd_ifname);
2128
2129         if (options.local_command != NULL) {
2130                 debug3("expanding LocalCommand: %s", options.local_command);
2131                 cp = options.local_command;
2132                 options.local_command = percent_expand(cp,
2133                     DEFAULT_CLIENT_PERCENT_EXPAND_ARGS(cinfo),
2134                     "T", tun_fwd_ifname == NULL ? "NONE" : tun_fwd_ifname,
2135                     (char *)NULL);
2136                 debug3("expanded LocalCommand: %s", options.local_command);
2137                 free(cp);
2138         }
2139
2140         /* Start listening for multiplex clients */
2141         if (!ssh_packet_get_mux(ssh))
2142                 muxserver_listen(ssh);
2143
2144         /*
2145          * If we are in control persist mode and have a working mux listen
2146          * socket, then prepare to background ourselves and have a foreground
2147          * client attach as a control client.
2148          * NB. we must save copies of the flags that we override for
2149          * the backgrounding, since we defer attachment of the client until
2150          * after the connection is fully established (in particular,
2151          * async rfwd replies have been received for ExitOnForwardFailure).
2152          */
2153         if (options.control_persist && muxserver_sock != -1) {
2154                 ostdin_null_flag = options.stdin_null;
2155                 osession_type = options.session_type;
2156                 orequest_tty = options.request_tty;
2157                 otty_flag = tty_flag;
2158                 options.stdin_null = 1;
2159                 options.session_type = SESSION_TYPE_NONE;
2160                 tty_flag = 0;
2161                 if (!options.fork_after_authentication &&
2162                     (osession_type != SESSION_TYPE_NONE ||
2163                     options.stdio_forward_host != NULL))
2164                         need_controlpersist_detach = 1;
2165                 options.fork_after_authentication = 1;
2166         }
2167         /*
2168          * ControlPersist mux listen socket setup failed, attempt the
2169          * stdio forward setup that we skipped earlier.
2170          */
2171         if (options.control_persist && muxserver_sock == -1)
2172                 ssh_init_stdio_forwarding(ssh);
2173
2174         if (options.session_type != SESSION_TYPE_NONE)
2175                 id = ssh_session2_open(ssh);
2176         else {
2177                 ssh_packet_set_interactive(ssh,
2178                     options.control_master == SSHCTL_MASTER_NO,
2179                     options.ip_qos_interactive, options.ip_qos_bulk);
2180         }
2181
2182         /* If we don't expect to open a new session, then disallow it */
2183         if (options.control_master == SSHCTL_MASTER_NO &&
2184             (ssh->compat & SSH_NEW_OPENSSH)) {
2185                 debug("Requesting no-more-sessions@openssh.com");
2186                 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 ||
2187                     (r = sshpkt_put_cstring(ssh,
2188                     "no-more-sessions@openssh.com")) != 0 ||
2189                     (r = sshpkt_put_u8(ssh, 0)) != 0 ||
2190                     (r = sshpkt_send(ssh)) != 0)
2191                         fatal_fr(r, "send packet");
2192         }
2193
2194         /* Execute a local command */
2195         if (options.local_command != NULL &&
2196             options.permit_local_command)
2197                 ssh_local_cmd(options.local_command);
2198
2199         /*
2200          * stdout is now owned by the session channel; clobber it here
2201          * so future channel closes are propagated to the local fd.
2202          * NB. this can only happen after LocalCommand has completed,
2203          * as it may want to write to stdout.
2204          */
2205         if (!need_controlpersist_detach && stdfd_devnull(0, 1, 0) == -1)
2206                 error_f("stdfd_devnull failed");
2207
2208         /*
2209          * If requested and we are not interested in replies to remote
2210          * forwarding requests, then let ssh continue in the background.
2211          */
2212         if (options.fork_after_authentication) {
2213                 if (options.exit_on_forward_failure &&
2214                     options.num_remote_forwards > 0) {
2215                         debug("deferring postauth fork until remote forward "
2216                             "confirmation received");
2217                 } else
2218                         fork_postauth();
2219         }
2220
2221         return client_loop(ssh, tty_flag, tty_flag ?
2222             options.escape_char : SSH_ESCAPECHAR_NONE, id);
2223 }
2224
2225 /* Loads all IdentityFile and CertificateFile keys */
2226 static void
2227 load_public_identity_files(const struct ssh_conn_info *cinfo)
2228 {
2229         char *filename, *cp;
2230         struct sshkey *public;
2231         int i;
2232         u_int n_ids, n_certs;
2233         char *identity_files[SSH_MAX_IDENTITY_FILES];
2234         struct sshkey *identity_keys[SSH_MAX_IDENTITY_FILES];
2235         int identity_file_userprovided[SSH_MAX_IDENTITY_FILES];
2236         char *certificate_files[SSH_MAX_CERTIFICATE_FILES];
2237         struct sshkey *certificates[SSH_MAX_CERTIFICATE_FILES];
2238         int certificate_file_userprovided[SSH_MAX_CERTIFICATE_FILES];
2239 #ifdef ENABLE_PKCS11
2240         struct sshkey **keys = NULL;
2241         char **comments = NULL;
2242         int nkeys;
2243 #endif /* PKCS11 */
2244
2245         n_ids = n_certs = 0;
2246         memset(identity_files, 0, sizeof(identity_files));
2247         memset(identity_keys, 0, sizeof(identity_keys));
2248         memset(identity_file_userprovided, 0,
2249             sizeof(identity_file_userprovided));
2250         memset(certificate_files, 0, sizeof(certificate_files));
2251         memset(certificates, 0, sizeof(certificates));
2252         memset(certificate_file_userprovided, 0,
2253             sizeof(certificate_file_userprovided));
2254
2255 #ifdef ENABLE_PKCS11
2256         if (options.pkcs11_provider != NULL &&
2257             options.num_identity_files < SSH_MAX_IDENTITY_FILES &&
2258             (pkcs11_init(!options.batch_mode) == 0) &&
2259             (nkeys = pkcs11_add_provider(options.pkcs11_provider, NULL,
2260             &keys, &comments)) > 0) {
2261                 for (i = 0; i < nkeys; i++) {
2262                         if (n_ids >= SSH_MAX_IDENTITY_FILES) {
2263                                 sshkey_free(keys[i]);
2264                                 free(comments[i]);
2265                                 continue;
2266                         }
2267                         identity_keys[n_ids] = keys[i];
2268                         identity_files[n_ids] = comments[i]; /* transferred */
2269                         n_ids++;
2270                 }
2271                 free(keys);
2272                 free(comments);
2273         }
2274 #endif /* ENABLE_PKCS11 */
2275         for (i = 0; i < options.num_identity_files; i++) {
2276                 if (n_ids >= SSH_MAX_IDENTITY_FILES ||
2277                     strcasecmp(options.identity_files[i], "none") == 0) {
2278                         free(options.identity_files[i]);
2279                         options.identity_files[i] = NULL;
2280                         continue;
2281                 }
2282                 cp = tilde_expand_filename(options.identity_files[i], getuid());
2283                 filename = default_client_percent_dollar_expand(cp, cinfo);
2284                 free(cp);
2285                 check_load(sshkey_load_public(filename, &public, NULL),
2286                     filename, "pubkey");
2287                 debug("identity file %s type %d", filename,
2288                     public ? public->type : -1);
2289                 free(options.identity_files[i]);
2290                 identity_files[n_ids] = filename;
2291                 identity_keys[n_ids] = public;
2292                 identity_file_userprovided[n_ids] =
2293                     options.identity_file_userprovided[i];
2294                 if (++n_ids >= SSH_MAX_IDENTITY_FILES)
2295                         continue;
2296
2297                 /*
2298                  * If no certificates have been explicitly listed then try
2299                  * to add the default certificate variant too.
2300                  */
2301                 if (options.num_certificate_files != 0)
2302                         continue;
2303                 xasprintf(&cp, "%s-cert", filename);
2304                 check_load(sshkey_load_public(cp, &public, NULL),
2305                     filename, "pubkey");
2306                 debug("identity file %s type %d", cp,
2307                     public ? public->type : -1);
2308                 if (public == NULL) {
2309                         free(cp);
2310                         continue;
2311                 }
2312                 if (!sshkey_is_cert(public)) {
2313                         debug_f("key %s type %s is not a certificate",
2314                             cp, sshkey_type(public));
2315                         sshkey_free(public);
2316                         free(cp);
2317                         continue;
2318                 }
2319                 /* NB. leave filename pointing to private key */
2320                 identity_files[n_ids] = xstrdup(filename);
2321                 identity_keys[n_ids] = public;
2322                 identity_file_userprovided[n_ids] =
2323                     options.identity_file_userprovided[i];
2324                 n_ids++;
2325         }
2326
2327         if (options.num_certificate_files > SSH_MAX_CERTIFICATE_FILES)
2328                 fatal_f("too many certificates");
2329         for (i = 0; i < options.num_certificate_files; i++) {
2330                 cp = tilde_expand_filename(options.certificate_files[i],
2331                     getuid());
2332                 filename = default_client_percent_dollar_expand(cp, cinfo);
2333                 free(cp);
2334
2335                 check_load(sshkey_load_public(filename, &public, NULL),
2336                     filename, "certificate");
2337                 debug("certificate file %s type %d", filename,
2338                     public ? public->type : -1);
2339                 free(options.certificate_files[i]);
2340                 options.certificate_files[i] = NULL;
2341                 if (public == NULL) {
2342                         free(filename);
2343                         continue;
2344                 }
2345                 if (!sshkey_is_cert(public)) {
2346                         debug_f("key %s type %s is not a certificate",
2347                             filename, sshkey_type(public));
2348                         sshkey_free(public);
2349                         free(filename);
2350                         continue;
2351                 }
2352                 certificate_files[n_certs] = filename;
2353                 certificates[n_certs] = public;
2354                 certificate_file_userprovided[n_certs] =
2355                     options.certificate_file_userprovided[i];
2356                 ++n_certs;
2357         }
2358
2359         options.num_identity_files = n_ids;
2360         memcpy(options.identity_files, identity_files, sizeof(identity_files));
2361         memcpy(options.identity_keys, identity_keys, sizeof(identity_keys));
2362         memcpy(options.identity_file_userprovided,
2363             identity_file_userprovided, sizeof(identity_file_userprovided));
2364
2365         options.num_certificate_files = n_certs;
2366         memcpy(options.certificate_files,
2367             certificate_files, sizeof(certificate_files));
2368         memcpy(options.certificates, certificates, sizeof(certificates));
2369         memcpy(options.certificate_file_userprovided,
2370             certificate_file_userprovided,
2371             sizeof(certificate_file_userprovided));
2372 }
2373
2374 static void
2375 main_sigchld_handler(int sig)
2376 {
2377         int save_errno = errno;
2378         pid_t pid;
2379         int status;
2380
2381         while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
2382             (pid == -1 && errno == EINTR))
2383                 ;
2384         errno = save_errno;
2385 }