crypto/openssh/ssh.c

   1 /* $OpenBSD: ssh.c,v 1.566 2021/08/08 08:49:09 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]\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
 264         snprintf(strport, sizeof strport, "%d", port);
 265         memset(&hints, 0, sizeof(hints));
 266         hints.ai_family = options.address_family == -1 ?
 267             AF_UNSPEC : options.address_family;
 268         hints.ai_socktype = SOCK_STREAM;
 269         if (cname != NULL)
 270                 hints.ai_flags = AI_CANONNAME;
 271         if ((gaierr = getaddrinfo(name, strport, &hints, &res)) != 0) {
 272                 if (logerr || (gaierr != EAI_NONAME && gaierr != EAI_NODATA))
 273                         loglevel = SYSLOG_LEVEL_ERROR;
 274                 do_log2(loglevel, "%s: Could not resolve hostname %.100s: %s",
 275                     __progname, name, ssh_gai_strerror(gaierr));
 276                 return NULL;
 277         }
 278         if (cname != NULL && res->ai_canonname != NULL) {
 279                 if (strlcpy(cname, res->ai_canonname, clen) >= clen) {
 280                         error_f("host \"%s\" cname \"%s\" too long (max %lu)",
 281                             name,  res->ai_canonname, (u_long)clen);
 282                         if (clen > 0)
 283                                 *cname = '\0';
 284                 }
 285         }
 286         return res;
 287 }
 288
 289 /* Returns non-zero if name can only be an address and not a hostname */
 290 static int
 291 is_addr_fast(const char *name)
 292 {
 293         return (strchr(name, '%') != NULL || strchr(name, ':') != NULL ||
 294             strspn(name, "0123456789.") == strlen(name));
 295 }
 296
 297 /* Returns non-zero if name represents a valid, single address */
 298 static int
 299 is_addr(const char *name)
 300 {
 301         char strport[NI_MAXSERV];
 302         struct addrinfo hints, *res;
 303
 304         if (is_addr_fast(name))
 305                 return 1;
 306
 307         snprintf(strport, sizeof strport, "%u", default_ssh_port());
 308         memset(&hints, 0, sizeof(hints));
 309         hints.ai_family = options.address_family == -1 ?
 310             AF_UNSPEC : options.address_family;
 311         hints.ai_socktype = SOCK_STREAM;
 312         hints.ai_flags = AI_NUMERICHOST|AI_NUMERICSERV;
 313         if (getaddrinfo(name, strport, &hints, &res) != 0)
 314                 return 0;
 315         if (res == NULL || res->ai_next != NULL) {
 316                 freeaddrinfo(res);
 317                 return 0;
 318         }
 319         freeaddrinfo(res);
 320         return 1;
 321 }
 322
 323 /*
 324  * Attempt to resolve a numeric host address / port to a single address.
 325  * Returns a canonical address string.
 326  * Returns NULL on failure.
 327  * NB. this function must operate with a options having undefined members.
 328  */
 329 static struct addrinfo *
 330 resolve_addr(const char *name, int port, char *caddr, size_t clen)
 331 {
 332         char addr[NI_MAXHOST], strport[NI_MAXSERV];
 333         struct addrinfo hints, *res;
 334         int gaierr;
 335
 336         if (port <= 0)
 337                 port = default_ssh_port();
 338         snprintf(strport, sizeof strport, "%u", port);
 339         memset(&hints, 0, sizeof(hints));
 340         hints.ai_family = options.address_family == -1 ?
 341             AF_UNSPEC : options.address_family;
 342         hints.ai_socktype = SOCK_STREAM;
 343         hints.ai_flags = AI_NUMERICHOST|AI_NUMERICSERV;
 344         if ((gaierr = getaddrinfo(name, strport, &hints, &res)) != 0) {
 345                 debug2_f("could not resolve name %.100s as address: %s",
 346                     name, ssh_gai_strerror(gaierr));
 347                 return NULL;
 348         }
 349         if (res == NULL) {
 350                 debug_f("getaddrinfo %.100s returned no addresses", name);
 351                 return NULL;
 352         }
 353         if (res->ai_next != NULL) {
 354                 debug_f("getaddrinfo %.100s returned multiple addresses", name);
 355                 goto fail;
 356         }
 357         if ((gaierr = getnameinfo(res->ai_addr, res->ai_addrlen,
 358             addr, sizeof(addr), NULL, 0, NI_NUMERICHOST)) != 0) {
 359                 debug_f("Could not format address for name %.100s: %s",
 360                     name, ssh_gai_strerror(gaierr));
 361                 goto fail;
 362         }
 363         if (strlcpy(caddr, addr, clen) >= clen) {
 364                 error_f("host \"%s\" addr \"%s\" too long (max %lu)",
 365                     name,  addr, (u_long)clen);
 366                 if (clen > 0)
 367                         *caddr = '\0';
 368  fail:
 369                 freeaddrinfo(res);
 370                 return NULL;
 371         }
 372         return res;
 373 }
 374
 375 /*
 376  * Check whether the cname is a permitted replacement for the hostname
 377  * and perform the replacement if it is.
 378  * NB. this function must operate with a options having undefined members.
 379  */
 380 static int
 381 check_follow_cname(int direct, char **namep, const char *cname)
 382 {
 383         int i;
 384         struct allowed_cname *rule;
 385
 386         if (*cname == '\0' || options.num_permitted_cnames == 0 ||
 387             strcmp(*namep, cname) == 0)
 388                 return 0;
 389         if (options.canonicalize_hostname == SSH_CANONICALISE_NO)
 390                 return 0;
 391         /*
 392          * Don't attempt to canonicalize names that will be interpreted by
 393          * a proxy or jump host unless the user specifically requests so.
 394          */
 395         if (!direct &&
 396             options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS)
 397                 return 0;
 398         debug3_f("check \"%s\" CNAME \"%s\"", *namep, cname);
 399         for (i = 0; i < options.num_permitted_cnames; i++) {
 400                 rule = options.permitted_cnames + i;
 401                 if (match_pattern_list(*namep, rule->source_list, 1) != 1 ||
 402                     match_pattern_list(cname, rule->target_list, 1) != 1)
 403                         continue;
 404                 verbose("Canonicalized DNS aliased hostname "
 405                     "\"%s\" => \"%s\"", *namep, cname);
 406                 free(*namep);
 407                 *namep = xstrdup(cname);
 408                 return 1;
 409         }
 410         return 0;
 411 }
 412
 413 /*
 414  * Attempt to resolve the supplied hostname after applying the user's
 415  * canonicalization rules. Returns the address list for the host or NULL
 416  * if no name was found after canonicalization.
 417  * NB. this function must operate with a options having undefined members.
 418  */
 419 static struct addrinfo *
 420 resolve_canonicalize(char **hostp, int port)
 421 {
 422         int i, direct, ndots;
 423         char *cp, *fullhost, newname[NI_MAXHOST];
 424         struct addrinfo *addrs;
 425
 426         /*
 427          * Attempt to canonicalise addresses, regardless of
 428          * whether hostname canonicalisation was requested
 429          */
 430         if ((addrs = resolve_addr(*hostp, port,
 431             newname, sizeof(newname))) != NULL) {
 432                 debug2_f("hostname %.100s is address", *hostp);
 433                 if (strcasecmp(*hostp, newname) != 0) {
 434                         debug2_f("canonicalised address \"%s\" => \"%s\"",
 435                             *hostp, newname);
 436                         free(*hostp);
 437                         *hostp = xstrdup(newname);
 438                 }
 439                 return addrs;
 440         }
 441
 442         /*
 443          * If this looks like an address but didn't parse as one, it might
 444          * be an address with an invalid interface scope. Skip further
 445          * attempts at canonicalisation.
 446          */
 447         if (is_addr_fast(*hostp)) {
 448                 debug_f("hostname %.100s is an unrecognised address", *hostp);
 449                 return NULL;
 450         }
 451
 452         if (options.canonicalize_hostname == SSH_CANONICALISE_NO)
 453                 return NULL;
 454
 455         /*
 456          * Don't attempt to canonicalize names that will be interpreted by
 457          * a proxy unless the user specifically requests so.
 458          */
 459         direct = option_clear_or_none(options.proxy_command) &&
 460             options.jump_host == NULL;
 461         if (!direct &&
 462             options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS)
 463                 return NULL;
 464
 465         /* If domain name is anchored, then resolve it now */
 466         if ((*hostp)[strlen(*hostp) - 1] == '.') {
 467                 debug3_f("name is fully qualified");
 468                 fullhost = xstrdup(*hostp);
 469                 if ((addrs = resolve_host(fullhost, port, 0,
 470                     newname, sizeof(newname))) != NULL)
 471                         goto found;
 472                 free(fullhost);
 473                 goto notfound;
 474         }
 475
 476         /* Don't apply canonicalization to sufficiently-qualified hostnames */
 477         ndots = 0;
 478         for (cp = *hostp; *cp != '\0'; cp++) {
 479                 if (*cp == '.')
 480                         ndots++;
 481         }
 482         if (ndots > options.canonicalize_max_dots) {
 483                 debug3_f("not canonicalizing hostname \"%s\" (max dots %d)",
 484                     *hostp, options.canonicalize_max_dots);
 485                 return NULL;
 486         }
 487         /* Attempt each supplied suffix */
 488         for (i = 0; i < options.num_canonical_domains; i++) {
 489                 if (strcasecmp(options.canonical_domains[i], "none") == 0)
 490                         break;
 491                 xasprintf(&fullhost, "%s.%s.", *hostp,
 492                     options.canonical_domains[i]);
 493                 debug3_f("attempting \"%s\" => \"%s\"", *hostp, fullhost);
 494                 if ((addrs = resolve_host(fullhost, port, 0,
 495                     newname, sizeof(newname))) == NULL) {
 496                         free(fullhost);
 497                         continue;
 498                 }
 499  found:
 500                 /* Remove trailing '.' */
 501                 fullhost[strlen(fullhost) - 1] = '\0';
 502                 /* Follow CNAME if requested */
 503                 if (!check_follow_cname(direct, &fullhost, newname)) {
 504                         debug("Canonicalized hostname \"%s\" => \"%s\"",
 505                             *hostp, fullhost);
 506                 }
 507                 free(*hostp);
 508                 *hostp = fullhost;
 509                 return addrs;
 510         }
 511  notfound:
 512         if (!options.canonicalize_fallback_local)
 513                 fatal("%s: Could not resolve host \"%s\"", __progname, *hostp);
 514         debug2_f("host %s not found in any suffix", *hostp);
 515         return NULL;
 516 }
 517
 518 /*
 519  * Check the result of hostkey loading, ignoring some errors and
 520  * fatal()ing for others.
 521  */
 522 static void
 523 check_load(int r, const char *path, const char *message)
 524 {
 525         switch (r) {
 526         case 0:
 527                 break;
 528         case SSH_ERR_INTERNAL_ERROR:
 529         case SSH_ERR_ALLOC_FAIL:
 530                 fatal_r(r, "load %s \"%s\"", message, path);
 531         case SSH_ERR_SYSTEM_ERROR:
 532                 /* Ignore missing files */
 533                 if (errno == ENOENT)
 534                         break;
 535                 /* FALLTHROUGH */
 536         default:
 537                 error_r(r, "load %s \"%s\"", message, path);
 538                 break;
 539         }
 540 }
 541
 542 /*
 543  * Read per-user configuration file.  Ignore the system wide config
 544  * file if the user specifies a config file on the command line.
 545  */
 546 static void
 547 process_config_files(const char *host_name, struct passwd *pw, int final_pass,
 548     int *want_final_pass)
 549 {
 550         char buf[PATH_MAX];
 551         int r;
 552
 553         if (config != NULL) {
 554                 if (strcasecmp(config, "none") != 0 &&
 555                     !read_config_file(config, pw, host, host_name, &options,
 556                     SSHCONF_USERCONF | (final_pass ? SSHCONF_FINAL : 0),
 557                     want_final_pass))
 558                         fatal("Can't open user config file %.100s: "
 559                             "%.100s", config, strerror(errno));
 560         } else {
 561                 r = snprintf(buf, sizeof buf, "%s/%s", pw->pw_dir,
 562                     _PATH_SSH_USER_CONFFILE);
 563                 if (r > 0 && (size_t)r < sizeof(buf))
 564                         (void)read_config_file(buf, pw, host, host_name,
 565                             &options, SSHCONF_CHECKPERM | SSHCONF_USERCONF |
 566                             (final_pass ? SSHCONF_FINAL : 0), want_final_pass);
 567
 568                 /* Read systemwide configuration file after user config. */
 569                 (void)read_config_file(_PATH_HOST_CONFIG_FILE, pw,
 570                     host, host_name, &options,
 571                     final_pass ? SSHCONF_FINAL : 0, want_final_pass);
 572         }
 573 }
 574
 575 /* Rewrite the port number in an addrinfo list of addresses */
 576 static void
 577 set_addrinfo_port(struct addrinfo *addrs, int port)
 578 {
 579         struct addrinfo *addr;
 580
 581         for (addr = addrs; addr != NULL; addr = addr->ai_next) {
 582                 switch (addr->ai_family) {
 583                 case AF_INET:
 584                         ((struct sockaddr_in *)addr->ai_addr)->
 585                             sin_port = htons(port);
 586                         break;
 587                 case AF_INET6:
 588                         ((struct sockaddr_in6 *)addr->ai_addr)->
 589                             sin6_port = htons(port);
 590                         break;
 591                 }
 592         }
 593 }
 594
 595 static void
 596 ssh_conn_info_free(struct ssh_conn_info *cinfo)
 597 {
 598         if (cinfo == NULL)
 599                 return;
 600         free(cinfo->conn_hash_hex);
 601         free(cinfo->shorthost);
 602         free(cinfo->uidstr);
 603         free(cinfo->keyalias);
 604         free(cinfo->thishost);
 605         free(cinfo->host_arg);
 606         free(cinfo->portstr);
 607         free(cinfo->remhost);
 608         free(cinfo->remuser);
 609         free(cinfo->homedir);
 610         free(cinfo->locuser);
 611         free(cinfo);
 612 }
 613
 614 /*
 615  * Main program for the ssh client.
 616  */
 617 int
 618 main(int ac, char **av)
 619 {
 620         struct ssh *ssh = NULL;
 621         int i, r, opt, exit_status, use_syslog, direct, timeout_ms;
 622         int was_addr, config_test = 0, opt_terminated = 0, want_final_pass = 0;
 623         char *p, *cp, *line, *argv0, *logfile, *host_arg;
 624         char cname[NI_MAXHOST], thishost[NI_MAXHOST];
 625         struct stat st;
 626         struct passwd *pw;
 627         extern int optind, optreset;
 628         extern char *optarg;
 629         struct Forward fwd;
 630         struct addrinfo *addrs = NULL;
 631         size_t n, len;
 632         u_int j;
 633         struct ssh_conn_info *cinfo = NULL;
 634
 635         /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
 636         sanitise_stdfd();
 637
 638         /*
 639          * Discard other fds that are hanging around. These can cause problem
 640          * with backgrounded ssh processes started by ControlPersist.
 641          */
 642         closefrom(STDERR_FILENO + 1);
 643
 644         __progname = ssh_get_progname(av[0]);
 645
 646 #ifndef HAVE_SETPROCTITLE
 647         /* Prepare for later setproctitle emulation */
 648         /* Save argv so it isn't clobbered by setproctitle() emulation */
 649         saved_av = xcalloc(ac + 1, sizeof(*saved_av));
 650         for (i = 0; i < ac; i++)
 651                 saved_av[i] = xstrdup(av[i]);
 652         saved_av[i] = NULL;
 653         compat_init_setproctitle(ac, av);
 654         av = saved_av;
 655 #endif
 656
 657         seed_rng();
 658
 659         /* Get user data. */
 660         pw = getpwuid(getuid());
 661         if (!pw) {
 662                 logit("No user exists for uid %lu", (u_long)getuid());
 663                 exit(255);
 664         }
 665         /* Take a copy of the returned structure. */
 666         pw = pwcopy(pw);
 667
 668         /*
 669          * Set our umask to something reasonable, as some files are created
 670          * with the default umask.  This will make them world-readable but
 671          * writable only by the owner, which is ok for all files for which we
 672          * don't set the modes explicitly.
 673          */
 674         umask(022);
 675
 676         msetlocale();
 677
 678         /*
 679          * Initialize option structure to indicate that no values have been
 680          * set.
 681          */
 682         initialize_options(&options);
 683
 684         /*
 685          * Prepare main ssh transport/connection structures
 686          */
 687         if ((ssh = ssh_alloc_session_state()) == NULL)
 688                 fatal("Couldn't allocate session state");
 689         channel_init_channels(ssh);
 690
 691         /* Parse command-line arguments. */
 692         host = NULL;
 693         use_syslog = 0;
 694         logfile = NULL;
 695         argv0 = av[0];
 696
 697  again:
 698         while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx"
 699             "AB:CD:E:F:GI:J:KL:MNO:PQ:R:S:TVw:W:XYy")) != -1) {
 700                 switch (opt) {
 701                 case '1':
 702                         fatal("SSH protocol v.1 is no longer supported");
 703                         break;
 704                 case '2':
 705                         /* Ignored */
 706                         break;
 707                 case '4':
 708                         options.address_family = AF_INET;
 709                         break;
 710                 case '6':
 711                         options.address_family = AF_INET6;
 712                         break;
 713                 case 'n':
 714                         options.stdin_null = 1;
 715                         break;
 716                 case 'f':
 717                         options.fork_after_authentication = 1;
 718                         options.stdin_null = 1;
 719                         break;
 720                 case 'x':
 721                         options.forward_x11 = 0;
 722                         break;
 723                 case 'X':
 724                         options.forward_x11 = 1;
 725                         break;
 726                 case 'y':
 727                         use_syslog = 1;
 728                         break;
 729                 case 'E':
 730                         logfile = optarg;
 731                         break;
 732                 case 'G':
 733                         config_test = 1;
 734                         break;
 735                 case 'Y':
 736                         options.forward_x11 = 1;
 737                         options.forward_x11_trusted = 1;
 738                         break;
 739                 case 'g':
 740                         options.fwd_opts.gateway_ports = 1;
 741                         break;
 742                 case 'O':
 743                         if (options.stdio_forward_host != NULL)
 744                                 fatal("Cannot specify multiplexing "
 745                                     "command with -W");
 746                         else if (muxclient_command != 0)
 747                                 fatal("Multiplexing command already specified");
 748                         if (strcmp(optarg, "check") == 0)
 749                                 muxclient_command = SSHMUX_COMMAND_ALIVE_CHECK;
 750                         else if (strcmp(optarg, "forward") == 0)
 751                                 muxclient_command = SSHMUX_COMMAND_FORWARD;
 752                         else if (strcmp(optarg, "exit") == 0)
 753                                 muxclient_command = SSHMUX_COMMAND_TERMINATE;
 754                         else if (strcmp(optarg, "stop") == 0)
 755                                 muxclient_command = SSHMUX_COMMAND_STOP;
 756                         else if (strcmp(optarg, "cancel") == 0)
 757                                 muxclient_command = SSHMUX_COMMAND_CANCEL_FWD;
 758                         else if (strcmp(optarg, "proxy") == 0)
 759                                 muxclient_command = SSHMUX_COMMAND_PROXY;
 760                         else
 761                                 fatal("Invalid multiplex command.");
 762                         break;
 763                 case 'P':       /* deprecated */
 764                         break;
 765                 case 'Q':
 766                         cp = NULL;
 767                         if (strcmp(optarg, "cipher") == 0 ||
 768                             strcasecmp(optarg, "Ciphers") == 0)
 769                                 cp = cipher_alg_list('\n', 0);
 770                         else if (strcmp(optarg, "cipher-auth") == 0)
 771                                 cp = cipher_alg_list('\n', 1);
 772                         else if (strcmp(optarg, "mac") == 0 ||
 773                             strcasecmp(optarg, "MACs") == 0)
 774                                 cp = mac_alg_list('\n');
 775                         else if (strcmp(optarg, "kex") == 0 ||
 776                             strcasecmp(optarg, "KexAlgorithms") == 0)
 777                                 cp = kex_alg_list('\n');
 778                         else if (strcmp(optarg, "key") == 0)
 779                                 cp = sshkey_alg_list(0, 0, 0, '\n');
 780                         else if (strcmp(optarg, "key-cert") == 0)
 781                                 cp = sshkey_alg_list(1, 0, 0, '\n');
 782                         else if (strcmp(optarg, "key-plain") == 0)
 783                                 cp = sshkey_alg_list(0, 1, 0, '\n');
 784                         else if (strcmp(optarg, "key-sig") == 0 ||
 785                             strcasecmp(optarg, "PubkeyAcceptedKeyTypes") == 0 || /* deprecated name */
 786                             strcasecmp(optarg, "PubkeyAcceptedAlgorithms") == 0 ||
 787                             strcasecmp(optarg, "HostKeyAlgorithms") == 0 ||
 788                             strcasecmp(optarg, "HostbasedKeyTypes") == 0 || /* deprecated name */
 789                             strcasecmp(optarg, "HostbasedAcceptedKeyTypes") == 0 || /* deprecated name */
 790                             strcasecmp(optarg, "HostbasedAcceptedAlgorithms") == 0)
 791                                 cp = sshkey_alg_list(0, 0, 1, '\n');
 792                         else if (strcmp(optarg, "sig") == 0)
 793                                 cp = sshkey_alg_list(0, 1, 1, '\n');
 794                         else if (strcmp(optarg, "protocol-version") == 0)
 795                                 cp = xstrdup("2");
 796                         else if (strcmp(optarg, "compression") == 0) {
 797                                 cp = xstrdup(compression_alg_list(0));
 798                                 len = strlen(cp);
 799                                 for (n = 0; n < len; n++)
 800                                         if (cp[n] == ',')
 801                                                 cp[n] = '\n';
 802                         } else if (strcmp(optarg, "help") == 0) {
 803                                 cp = xstrdup(
 804                                     "cipher\ncipher-auth\ncompression\nkex\n"
 805                                     "key\nkey-cert\nkey-plain\nkey-sig\nmac\n"
 806                                     "protocol-version\nsig");
 807                         }
 808                         if (cp == NULL)
 809                                 fatal("Unsupported query \"%s\"", optarg);
 810                         printf("%s\n", cp);
 811                         free(cp);
 812                         exit(0);
 813                         break;
 814                 case 'a':
 815                         options.forward_agent = 0;
 816                         break;
 817                 case 'A':
 818                         options.forward_agent = 1;
 819                         break;
 820                 case 'k':
 821                         options.gss_deleg_creds = 0;
 822                         break;
 823                 case 'K':
 824                         options.gss_authentication = 1;
 825                         options.gss_deleg_creds = 1;
 826                         break;
 827                 case 'i':
 828                         p = tilde_expand_filename(optarg, getuid());
 829                         if (stat(p, &st) == -1)
 830                                 fprintf(stderr, "Warning: Identity file %s "
 831                                     "not accessible: %s.\n", p,
 832                                     strerror(errno));
 833                         else
 834                                 add_identity_file(&options, NULL, p, 1);
 835                         free(p);
 836                         break;
 837                 case 'I':
 838 #ifdef ENABLE_PKCS11
 839                         free(options.pkcs11_provider);
 840                         options.pkcs11_provider = xstrdup(optarg);
 841 #else
 842                         fprintf(stderr, "no support for PKCS#11.\n");
 843 #endif
 844                         break;
 845                 case 'J':
 846                         if (options.jump_host != NULL) {
 847                                 fatal("Only a single -J option is permitted "
 848                                     "(use commas to separate multiple "
 849                                     "jump hops)");
 850                         }
 851                         if (options.proxy_command != NULL)
 852                                 fatal("Cannot specify -J with ProxyCommand");
 853                         if (parse_jump(optarg, &options, 1) == -1)
 854                                 fatal("Invalid -J argument");
 855                         options.proxy_command = xstrdup("none");
 856                         break;
 857                 case 't':
 858                         if (options.request_tty == REQUEST_TTY_YES)
 859                                 options.request_tty = REQUEST_TTY_FORCE;
 860                         else
 861                                 options.request_tty = REQUEST_TTY_YES;
 862                         break;
 863                 case 'v':
 864                         if (debug_flag == 0) {
 865                                 debug_flag = 1;
 866                                 options.log_level = SYSLOG_LEVEL_DEBUG1;
 867                         } else {
 868                                 if (options.log_level < SYSLOG_LEVEL_DEBUG3) {
 869                                         debug_flag++;
 870                                         options.log_level++;
 871                                 }
 872                         }
 873                         break;
 874                 case 'V':
 875                         if (options.version_addendum &&
 876                             *options.version_addendum != '\0')
 877                                 fprintf(stderr, "%s %s, %s\n", SSH_RELEASE,
 878                                     options.version_addendum,
 879                                     OPENSSL_VERSION_STRING);
 880                         else
 881                                 fprintf(stderr, "%s, %s\n", SSH_RELEASE,
 882                                     OPENSSL_VERSION_STRING);
 883                         if (opt == 'V')
 884                                 exit(0);
 885                         break;
 886                 case 'w':
 887                         if (options.tun_open == -1)
 888                                 options.tun_open = SSH_TUNMODE_DEFAULT;
 889                         options.tun_local = a2tun(optarg, &options.tun_remote);
 890                         if (options.tun_local == SSH_TUNID_ERR) {
 891                                 fprintf(stderr,
 892                                     "Bad tun device '%s'\n", optarg);
 893                                 exit(255);
 894                         }
 895                         break;
 896                 case 'W':
 897                         if (options.stdio_forward_host != NULL)
 898                                 fatal("stdio forward already specified");
 899                         if (muxclient_command != 0)
 900                                 fatal("Cannot specify stdio forward with -O");
 901                         if (parse_forward(&fwd, optarg, 1, 0)) {
 902                                 options.stdio_forward_host = fwd.listen_host;
 903                                 options.stdio_forward_port = fwd.listen_port;
 904                                 free(fwd.connect_host);
 905                         } else {
 906                                 fprintf(stderr,
 907                                     "Bad stdio forwarding specification '%s'\n",
 908                                     optarg);
 909                                 exit(255);
 910                         }
 911                         options.request_tty = REQUEST_TTY_NO;
 912                         options.session_type = SESSION_TYPE_NONE;
 913                         break;
 914                 case 'q':
 915                         options.log_level = SYSLOG_LEVEL_QUIET;
 916                         break;
 917                 case 'e':
 918                         if (optarg[0] == '^' && optarg[2] == 0 &&
 919                             (u_char) optarg[1] >= 64 &&
 920                             (u_char) optarg[1] < 128)
 921                                 options.escape_char = (u_char) optarg[1] & 31;
 922                         else if (strlen(optarg) == 1)
 923                                 options.escape_char = (u_char) optarg[0];
 924                         else if (strcmp(optarg, "none") == 0)
 925                                 options.escape_char = SSH_ESCAPECHAR_NONE;
 926                         else {
 927                                 fprintf(stderr, "Bad escape character '%s'.\n",
 928                                     optarg);
 929                                 exit(255);
 930                         }
 931                         break;
 932                 case 'c':
 933                         if (!ciphers_valid(*optarg == '+' || *optarg == '^' ?
 934                             optarg + 1 : optarg)) {
 935                                 fprintf(stderr, "Unknown cipher type '%s'\n",
 936                                     optarg);
 937                                 exit(255);
 938                         }
 939                         free(options.ciphers);
 940                         options.ciphers = xstrdup(optarg);
 941                         break;
 942                 case 'm':
 943                         if (mac_valid(optarg)) {
 944                                 free(options.macs);
 945                                 options.macs = xstrdup(optarg);
 946                         } else {
 947                                 fprintf(stderr, "Unknown mac type '%s'\n",
 948                                     optarg);
 949                                 exit(255);
 950                         }
 951                         break;
 952                 case 'M':
 953                         if (options.control_master == SSHCTL_MASTER_YES)
 954                                 options.control_master = SSHCTL_MASTER_ASK;
 955                         else
 956                                 options.control_master = SSHCTL_MASTER_YES;
 957                         break;
 958                 case 'p':
 959                         if (options.port == -1) {
 960                                 options.port = a2port(optarg);
 961                                 if (options.port <= 0) {
 962                                         fprintf(stderr, "Bad port '%s'\n",
 963                                             optarg);
 964                                         exit(255);
 965                                 }
 966                         }
 967                         break;
 968                 case 'l':
 969                         if (options.user == NULL)
 970                                 options.user = optarg;
 971                         break;
 972
 973                 case 'L':
 974                         if (parse_forward(&fwd, optarg, 0, 0))
 975                                 add_local_forward(&options, &fwd);
 976                         else {
 977                                 fprintf(stderr,
 978                                     "Bad local forwarding specification '%s'\n",
 979                                     optarg);
 980                                 exit(255);
 981                         }
 982                         break;
 983
 984                 case 'R':
 985                         if (parse_forward(&fwd, optarg, 0, 1) ||
 986                             parse_forward(&fwd, optarg, 1, 1)) {
 987                                 add_remote_forward(&options, &fwd);
 988                         } else {
 989                                 fprintf(stderr,
 990                                     "Bad remote forwarding specification "
 991                                     "'%s'\n", optarg);
 992                                 exit(255);
 993                         }
 994                         break;
 995
 996                 case 'D':
 997                         if (parse_forward(&fwd, optarg, 1, 0)) {
 998                                 add_local_forward(&options, &fwd);
 999                         } else {
1000                                 fprintf(stderr,
1001                                     "Bad dynamic forwarding specification "
1002                                     "'%s'\n", optarg);
1003                                 exit(255);
1004                         }
1005                         break;
1006
1007                 case 'C':
1008 #ifdef WITH_ZLIB
1009                         options.compression = 1;
1010 #else
1011                         error("Compression not supported, disabling.");
1012 #endif
1013                         break;
1014                 case 'N':
1015                         if (options.session_type != -1 &&
1016                             options.session_type != SESSION_TYPE_NONE)
1017                                 fatal("Cannot specify -N with -s/SessionType");
1018                         options.session_type = SESSION_TYPE_NONE;
1019                         options.request_tty = REQUEST_TTY_NO;
1020                         break;
1021                 case 'T':
1022                         options.request_tty = REQUEST_TTY_NO;
1023                         break;
1024                 case 'o':
1025                         line = xstrdup(optarg);
1026                         if (process_config_line(&options, pw,
1027                             host ? host : "", host ? host : "", line,
1028                             "command-line", 0, NULL, SSHCONF_USERCONF) != 0)
1029                                 exit(255);
1030                         free(line);
1031                         break;
1032                 case 's':
1033                         if (options.session_type != -1 &&
1034                             options.session_type != SESSION_TYPE_SUBSYSTEM)
1035                                 fatal("Cannot specify -s with -N/SessionType");
1036                         options.session_type = SESSION_TYPE_SUBSYSTEM;
1037                         break;
1038                 case 'S':
1039                         free(options.control_path);
1040                         options.control_path = xstrdup(optarg);
1041                         break;
1042                 case 'b':
1043                         options.bind_address = optarg;
1044                         break;
1045                 case 'B':
1046                         options.bind_interface = optarg;
1047                         break;
1048                 case 'F':
1049                         config = optarg;
1050                         break;
1051                 default:
1052                         usage();
1053                 }
1054         }
1055
1056         if (optind > 1 && strcmp(av[optind - 1], "--") == 0)
1057                 opt_terminated = 1;
1058
1059         ac -= optind;
1060         av += optind;
1061
1062         if (ac > 0 && !host) {
1063                 int tport;
1064                 char *tuser;
1065                 switch (parse_ssh_uri(*av, &tuser, &host, &tport)) {
1066                 case -1:
1067                         usage();
1068                         break;
1069                 case 0:
1070                         if (options.user == NULL) {
1071                                 options.user = tuser;
1072                                 tuser = NULL;
1073                         }
1074                         free(tuser);
1075                         if (options.port == -1 && tport != -1)
1076                                 options.port = tport;
1077                         break;
1078                 default:
1079                         p = xstrdup(*av);
1080                         cp = strrchr(p, '@');
1081                         if (cp != NULL) {
1082                                 if (cp == p)
1083                                         usage();
1084                                 if (options.user == NULL) {
1085                                         options.user = p;
1086                                         p = NULL;
1087                                 }
1088                                 *cp++ = '\0';
1089                                 host = xstrdup(cp);
1090                                 free(p);
1091                         } else
1092                                 host = p;
1093                         break;
1094                 }
1095                 if (ac > 1 && !opt_terminated) {
1096                         optind = optreset = 1;
1097                         goto again;
1098                 }
1099                 ac--, av++;
1100         }
1101
1102         /* Check that we got a host name. */
1103         if (!host)
1104                 usage();
1105
1106         host_arg = xstrdup(host);
1107
1108         /* Initialize the command to execute on remote host. */
1109         if ((command = sshbuf_new()) == NULL)
1110                 fatal("sshbuf_new failed");
1111
1112         /*
1113          * Save the command to execute on the remote host in a buffer. There
1114          * is no limit on the length of the command, except by the maximum
1115          * packet size.  Also sets the tty flag if there is no command.
1116          */
1117         if (!ac) {
1118                 /* No command specified - execute shell on a tty. */
1119                 if (options.session_type == SESSION_TYPE_SUBSYSTEM) {
1120                         fprintf(stderr,
1121                             "You must specify a subsystem to invoke.\n");
1122                         usage();
1123                 }
1124         } else {
1125                 /* A command has been specified.  Store it into the buffer. */
1126                 for (i = 0; i < ac; i++) {
1127                         if ((r = sshbuf_putf(command, "%s%s",
1128                             i ? " " : "", av[i])) != 0)
1129                                 fatal_fr(r, "buffer error");
1130                 }
1131         }
1132
1133         /*
1134          * Initialize "log" output.  Since we are the client all output
1135          * goes to stderr unless otherwise specified by -y or -E.
1136          */
1137         if (use_syslog && logfile != NULL)
1138                 fatal("Can't specify both -y and -E");
1139         if (logfile != NULL)
1140                 log_redirect_stderr_to(logfile);
1141         log_init(argv0,
1142             options.log_level == SYSLOG_LEVEL_NOT_SET ?
1143             SYSLOG_LEVEL_INFO : options.log_level,
1144             options.log_facility == SYSLOG_FACILITY_NOT_SET ?
1145             SYSLOG_FACILITY_USER : options.log_facility,
1146             !use_syslog);
1147
1148         if (debug_flag)
1149                 /* version_addendum is always NULL at this point */
1150                 logit("%s, %s", SSH_RELEASE, OPENSSL_VERSION_STRING);
1151
1152         /* Parse the configuration files */
1153         process_config_files(host_arg, pw, 0, &want_final_pass);
1154         if (want_final_pass)
1155                 debug("configuration requests final Match pass");
1156
1157         /* Hostname canonicalisation needs a few options filled. */
1158         fill_default_options_for_canonicalization(&options);
1159
1160         /* If the user has replaced the hostname then take it into use now */
1161         if (options.hostname != NULL) {
1162                 /* NB. Please keep in sync with readconf.c:match_cfg_line() */
1163                 cp = percent_expand(options.hostname,
1164                     "h", host, (char *)NULL);
1165                 free(host);
1166                 host = cp;
1167                 free(options.hostname);
1168                 options.hostname = xstrdup(host);
1169         }
1170
1171         /* Don't lowercase addresses, they will be explicitly canonicalised */
1172         if ((was_addr = is_addr(host)) == 0)
1173                 lowercase(host);
1174
1175         /*
1176          * Try to canonicalize if requested by configuration or the
1177          * hostname is an address.
1178          */
1179         if (options.canonicalize_hostname != SSH_CANONICALISE_NO || was_addr)
1180                 addrs = resolve_canonicalize(&host, options.port);
1181
1182         /*
1183          * If CanonicalizePermittedCNAMEs have been specified but
1184          * other canonicalization did not happen (by not being requested
1185          * or by failing with fallback) then the hostname may still be changed
1186          * as a result of CNAME following.
1187          *
1188          * Try to resolve the bare hostname name using the system resolver's
1189          * usual search rules and then apply the CNAME follow rules.
1190          *
1191          * Skip the lookup if a ProxyCommand is being used unless the user
1192          * has specifically requested canonicalisation for this case via
1193          * CanonicalizeHostname=always
1194          */
1195         direct = option_clear_or_none(options.proxy_command) &&
1196             options.jump_host == NULL;
1197         if (addrs == NULL && options.num_permitted_cnames != 0 && (direct ||
1198             options.canonicalize_hostname == SSH_CANONICALISE_ALWAYS)) {
1199                 if ((addrs = resolve_host(host, options.port,
1200                     direct, cname, sizeof(cname))) == NULL) {
1201                         /* Don't fatal proxied host names not in the DNS */
1202                         if (direct)
1203                                 cleanup_exit(255); /* logged in resolve_host */
1204                 } else
1205                         check_follow_cname(direct, &host, cname);
1206         }
1207
1208         /*
1209          * If canonicalisation is enabled then re-parse the configuration
1210          * files as new stanzas may match.
1211          */
1212         if (options.canonicalize_hostname != 0 && !want_final_pass) {
1213                 debug("hostname canonicalisation enabled, "
1214                     "will re-parse configuration");
1215                 want_final_pass = 1;
1216         }
1217
1218         if (want_final_pass) {
1219                 debug("re-parsing configuration");
1220                 free(options.hostname);
1221                 options.hostname = xstrdup(host);
1222                 process_config_files(host_arg, pw, 1, NULL);
1223                 /*
1224                  * Address resolution happens early with canonicalisation
1225                  * enabled and the port number may have changed since, so
1226                  * reset it in address list
1227                  */
1228                 if (addrs != NULL && options.port > 0)
1229                         set_addrinfo_port(addrs, options.port);
1230         }
1231
1232         /* Fill configuration defaults. */
1233         if (fill_default_options(&options) != 0)
1234                 cleanup_exit(255);
1235
1236         if (options.user == NULL)
1237                 options.user = xstrdup(pw->pw_name);
1238
1239         /*
1240          * If ProxyJump option specified, then construct a ProxyCommand now.
1241          */
1242         if (options.jump_host != NULL) {
1243                 char port_s[8];
1244                 const char *jumpuser = options.jump_user, *sshbin = argv0;
1245                 int port = options.port, jumpport = options.jump_port;
1246
1247                 if (port <= 0)
1248                         port = default_ssh_port();
1249                 if (jumpport <= 0)
1250                         jumpport = default_ssh_port();
1251                 if (jumpuser == NULL)
1252                         jumpuser = options.user;
1253                 if (strcmp(options.jump_host, host) == 0 && port == jumpport &&
1254                     strcmp(options.user, jumpuser) == 0)
1255                         fatal("jumphost loop via %s", options.jump_host);
1256
1257                 /*
1258                  * Try to use SSH indicated by argv[0], but fall back to
1259                  * "ssh" if it appears unavailable.
1260                  */
1261                 if (strchr(argv0, '/') != NULL && access(argv0, X_OK) != 0)
1262                         sshbin = "ssh";
1263
1264                 /* Consistency check */
1265                 if (options.proxy_command != NULL)
1266                         fatal("inconsistent options: ProxyCommand+ProxyJump");
1267                 /* Never use FD passing for ProxyJump */
1268                 options.proxy_use_fdpass = 0;
1269                 snprintf(port_s, sizeof(port_s), "%d", options.jump_port);
1270                 xasprintf(&options.proxy_command,
1271                     "%s%s%s%s%s%s%s%s%s%s%.*s -W '[%%h]:%%p' %s",
1272                     sshbin,
1273                     /* Optional "-l user" argument if jump_user set */
1274                     options.jump_user == NULL ? "" : " -l ",
1275                     options.jump_user == NULL ? "" : options.jump_user,
1276                     /* Optional "-p port" argument if jump_port set */
1277                     options.jump_port <= 0 ? "" : " -p ",
1278                     options.jump_port <= 0 ? "" : port_s,
1279                     /* Optional additional jump hosts ",..." */
1280                     options.jump_extra == NULL ? "" : " -J ",
1281                     options.jump_extra == NULL ? "" : options.jump_extra,
1282                     /* Optional "-F" argumment if -F specified */
1283                     config == NULL ? "" : " -F ",
1284                     config == NULL ? "" : config,
1285                     /* Optional "-v" arguments if -v set */
1286                     debug_flag ? " -" : "",
1287                     debug_flag, "vvv",
1288                     /* Mandatory hostname */
1289                     options.jump_host);
1290                 debug("Setting implicit ProxyCommand from ProxyJump: %s",
1291                     options.proxy_command);
1292         }
1293
1294         if (options.port == 0)
1295                 options.port = default_ssh_port();
1296         channel_set_af(ssh, options.address_family);
1297
1298         /* Tidy and check options */
1299         if (options.host_key_alias != NULL)
1300                 lowercase(options.host_key_alias);
1301         if (options.proxy_command != NULL &&
1302             strcmp(options.proxy_command, "-") == 0 &&
1303             options.proxy_use_fdpass)
1304                 fatal("ProxyCommand=- and ProxyUseFDPass are incompatible");
1305         if (options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK) {
1306                 if (options.control_persist && options.control_path != NULL) {
1307                         debug("UpdateHostKeys=ask is incompatible with "
1308                             "ControlPersist; disabling");
1309                         options.update_hostkeys = 0;
1310                 } else if (sshbuf_len(command) != 0 ||
1311                     options.remote_command != NULL ||
1312                     options.request_tty == REQUEST_TTY_NO) {
1313                         debug("UpdateHostKeys=ask is incompatible with "
1314                             "remote command execution; disabling");
1315                         options.update_hostkeys = 0;
1316                 } else if (options.log_level < SYSLOG_LEVEL_INFO) {
1317                         /* no point logging anything; user won't see it */
1318                         options.update_hostkeys = 0;
1319                 }
1320         }
1321         if (options.connection_attempts <= 0)
1322                 fatal("Invalid number of ConnectionAttempts");
1323
1324         if (sshbuf_len(command) != 0 && options.remote_command != NULL)
1325                 fatal("Cannot execute command-line and remote command.");
1326
1327         /* Cannot fork to background if no command. */
1328         if (options.fork_after_authentication && sshbuf_len(command) == 0 &&
1329             options.remote_command == NULL &&
1330             options.session_type != SESSION_TYPE_NONE)
1331                 fatal("Cannot fork into background without a command "
1332                     "to execute.");
1333
1334         /* reinit */
1335         log_init(argv0, options.log_level, options.log_facility, !use_syslog);
1336         for (j = 0; j < options.num_log_verbose; j++) {
1337                 if (strcasecmp(options.log_verbose[j], "none") == 0)
1338                         break;
1339                 log_verbose_add(options.log_verbose[j]);
1340         }
1341
1342         if (options.request_tty == REQUEST_TTY_YES ||
1343             options.request_tty == REQUEST_TTY_FORCE)
1344                 tty_flag = 1;
1345
1346         /* Allocate a tty by default if no command specified. */
1347         if (sshbuf_len(command) == 0 && options.remote_command == NULL)
1348                 tty_flag = options.request_tty != REQUEST_TTY_NO;
1349
1350         /* Force no tty */
1351         if (options.request_tty == REQUEST_TTY_NO ||
1352             (muxclient_command && muxclient_command != SSHMUX_COMMAND_PROXY))
1353                 tty_flag = 0;
1354         /* Do not allocate a tty if stdin is not a tty. */
1355         if ((!isatty(fileno(stdin)) || options.stdin_null) &&
1356             options.request_tty != REQUEST_TTY_FORCE) {
1357                 if (tty_flag)
1358                         logit("Pseudo-terminal will not be allocated because "
1359                             "stdin is not a terminal.");
1360                 tty_flag = 0;
1361         }
1362
1363         /* Set up strings used to percent_expand() arguments */
1364         cinfo = xcalloc(1, sizeof(*cinfo));
1365         if (gethostname(thishost, sizeof(thishost)) == -1)
1366                 fatal("gethostname: %s", strerror(errno));
1367         cinfo->thishost = xstrdup(thishost);
1368         thishost[strcspn(thishost, ".")] = '\0';
1369         cinfo->shorthost = xstrdup(thishost);
1370         xasprintf(&cinfo->portstr, "%d", options.port);
1371         xasprintf(&cinfo->uidstr, "%llu",
1372             (unsigned long long)pw->pw_uid);
1373         cinfo->keyalias = xstrdup(options.host_key_alias ?
1374             options.host_key_alias : host_arg);
1375         cinfo->conn_hash_hex = ssh_connection_hash(cinfo->thishost, host,
1376             cinfo->portstr, options.user);
1377         cinfo->host_arg = xstrdup(host_arg);
1378         cinfo->remhost = xstrdup(host);
1379         cinfo->remuser = xstrdup(options.user);
1380         cinfo->homedir = xstrdup(pw->pw_dir);
1381         cinfo->locuser = xstrdup(pw->pw_name);
1382
1383         /* Find canonic host name. */
1384         if (strchr(host, '.') == 0) {
1385                 struct addrinfo hints;
1386                 struct addrinfo *ai = NULL;
1387                 int errgai;
1388                 memset(&hints, 0, sizeof(hints));
1389                 hints.ai_family = options.address_family;
1390                 hints.ai_flags = AI_CANONNAME;
1391                 hints.ai_socktype = SOCK_STREAM;
1392                 errgai = getaddrinfo(host, NULL, &hints, &ai);
1393                 if (errgai == 0) {
1394                         if (ai->ai_canonname != NULL)
1395                                 host = xstrdup(ai->ai_canonname);
1396                         freeaddrinfo(ai);
1397                 }
1398         }
1399
1400         /*
1401          * Expand tokens in arguments. NB. LocalCommand is expanded later,
1402          * after port-forwarding is set up, so it may pick up any local
1403          * tunnel interface name allocated.
1404          */
1405         if (options.remote_command != NULL) {
1406                 debug3("expanding RemoteCommand: %s", options.remote_command);
1407                 cp = options.remote_command;
1408                 options.remote_command = default_client_percent_expand(cp,
1409                     cinfo);
1410                 debug3("expanded RemoteCommand: %s", options.remote_command);
1411                 free(cp);
1412                 if ((r = sshbuf_put(command, options.remote_command,
1413                     strlen(options.remote_command))) != 0)
1414                         fatal_fr(r, "buffer error");
1415         }
1416
1417         if (options.control_path != NULL) {
1418                 cp = tilde_expand_filename(options.control_path, getuid());
1419                 free(options.control_path);
1420                 options.control_path = default_client_percent_dollar_expand(cp,
1421                     cinfo);
1422                 free(cp);
1423         }
1424
1425         if (options.identity_agent != NULL) {
1426                 p = tilde_expand_filename(options.identity_agent, getuid());
1427                 cp = default_client_percent_dollar_expand(p, cinfo);
1428                 free(p);
1429                 free(options.identity_agent);
1430                 options.identity_agent = cp;
1431         }
1432
1433         if (options.forward_agent_sock_path != NULL) {
1434                 p = tilde_expand_filename(options.forward_agent_sock_path,
1435                     getuid());
1436                 cp = default_client_percent_dollar_expand(p, cinfo);
1437                 free(p);
1438                 free(options.forward_agent_sock_path);
1439                 options.forward_agent_sock_path = cp;
1440                 if (stat(options.forward_agent_sock_path, &st) != 0) {
1441                         error("Cannot forward agent socket path \"%s\": %s",
1442                             options.forward_agent_sock_path, strerror(errno));
1443                         if (options.exit_on_forward_failure)
1444                                 cleanup_exit(255);
1445                 }
1446         }
1447
1448         if (options.num_system_hostfiles > 0 &&
1449             strcasecmp(options.system_hostfiles[0], "none") == 0) {
1450                 if (options.num_system_hostfiles > 1)
1451                         fatal("Invalid GlobalKnownHostsFiles: \"none\" "
1452                             "appears with other entries");
1453                 free(options.system_hostfiles[0]);
1454                 options.system_hostfiles[0] = NULL;
1455                 options.num_system_hostfiles = 0;
1456         }
1457
1458         if (options.num_user_hostfiles > 0 &&
1459             strcasecmp(options.user_hostfiles[0], "none") == 0) {
1460                 if (options.num_user_hostfiles > 1)
1461                         fatal("Invalid UserKnownHostsFiles: \"none\" "
1462                             "appears with other entries");
1463                 free(options.user_hostfiles[0]);
1464                 options.user_hostfiles[0] = NULL;
1465                 options.num_user_hostfiles = 0;
1466         }
1467         for (j = 0; j < options.num_user_hostfiles; j++) {
1468                 if (options.user_hostfiles[j] == NULL)
1469                         continue;
1470                 cp = tilde_expand_filename(options.user_hostfiles[j], getuid());
1471                 p = default_client_percent_dollar_expand(cp, cinfo);
1472                 if (strcmp(options.user_hostfiles[j], p) != 0)
1473                         debug3("expanded UserKnownHostsFile '%s' -> "
1474                             "'%s'", options.user_hostfiles[j], p);
1475                 free(options.user_hostfiles[j]);
1476                 free(cp);
1477                 options.user_hostfiles[j] = p;
1478         }
1479
1480         for (i = 0; i < options.num_local_forwards; i++) {
1481                 if (options.local_forwards[i].listen_path != NULL) {
1482                         cp = options.local_forwards[i].listen_path;
1483                         p = options.local_forwards[i].listen_path =
1484                             default_client_percent_expand(cp, cinfo);
1485                         if (strcmp(cp, p) != 0)
1486                                 debug3("expanded LocalForward listen path "
1487                                     "'%s' -> '%s'", cp, p);
1488                         free(cp);
1489                 }
1490                 if (options.local_forwards[i].connect_path != NULL) {
1491                         cp = options.local_forwards[i].connect_path;
1492                         p = options.local_forwards[i].connect_path =
1493                             default_client_percent_expand(cp, cinfo);
1494                         if (strcmp(cp, p) != 0)
1495                                 debug3("expanded LocalForward connect path "
1496                                     "'%s' -> '%s'", cp, p);
1497                         free(cp);
1498                 }
1499         }
1500
1501         for (i = 0; i < options.num_remote_forwards; i++) {
1502                 if (options.remote_forwards[i].listen_path != NULL) {
1503                         cp = options.remote_forwards[i].listen_path;
1504                         p = options.remote_forwards[i].listen_path =
1505                             default_client_percent_expand(cp, cinfo);
1506                         if (strcmp(cp, p) != 0)
1507                                 debug3("expanded RemoteForward listen path "
1508                                     "'%s' -> '%s'", cp, p);
1509                         free(cp);
1510                 }
1511                 if (options.remote_forwards[i].connect_path != NULL) {
1512                         cp = options.remote_forwards[i].connect_path;
1513                         p = options.remote_forwards[i].connect_path =
1514                             default_client_percent_expand(cp, cinfo);
1515                         if (strcmp(cp, p) != 0)
1516                                 debug3("expanded RemoteForward connect path "
1517                                     "'%s' -> '%s'", cp, p);
1518                         free(cp);
1519                 }
1520         }
1521
1522         if (config_test) {
1523                 dump_client_config(&options, host);
1524                 exit(0);
1525         }
1526
1527         /* Expand SecurityKeyProvider if it refers to an environment variable */
1528         if (options.sk_provider != NULL && *options.sk_provider == '$' &&
1529             strlen(options.sk_provider) > 1) {
1530                 if ((cp = getenv(options.sk_provider + 1)) == NULL) {
1531                         debug("Authenticator provider %s did not resolve; "
1532                             "disabling", options.sk_provider);
1533                         free(options.sk_provider);
1534                         options.sk_provider = NULL;
1535                 } else {
1536                         debug2("resolved SecurityKeyProvider %s => %s",
1537                             options.sk_provider, cp);
1538                         free(options.sk_provider);
1539                         options.sk_provider = xstrdup(cp);
1540                 }
1541         }
1542
1543         if (muxclient_command != 0 && options.control_path == NULL)
1544                 fatal("No ControlPath specified for \"-O\" command");
1545         if (options.control_path != NULL) {
1546                 int sock;
1547                 if ((sock = muxclient(options.control_path)) >= 0) {
1548                         ssh_packet_set_connection(ssh, sock, sock);
1549                         ssh_packet_set_mux(ssh);
1550                         goto skip_connect;
1551                 }
1552         }
1553
1554         /*
1555          * If hostname canonicalisation was not enabled, then we may not
1556          * have yet resolved the hostname. Do so now.
1557          */
1558         if (addrs == NULL && options.proxy_command == NULL) {
1559                 debug2("resolving \"%s\" port %d", host, options.port);
1560                 if ((addrs = resolve_host(host, options.port, 1,
1561                     cname, sizeof(cname))) == NULL)
1562                         cleanup_exit(255); /* resolve_host logs the error */
1563         }
1564
1565         if (options.connection_timeout >= INT_MAX/1000)
1566                 timeout_ms = INT_MAX;
1567         else
1568                 timeout_ms = options.connection_timeout * 1000;
1569
1570         /* Open a connection to the remote host. */
1571         if (ssh_connect(ssh, host, host_arg, addrs, &hostaddr, options.port,
1572             options.connection_attempts,
1573             &timeout_ms, options.tcp_keep_alive) != 0)
1574                 exit(255);
1575
1576         if (addrs != NULL)
1577                 freeaddrinfo(addrs);
1578
1579         ssh_packet_set_timeout(ssh, options.server_alive_interval,
1580             options.server_alive_count_max);
1581
1582         if (timeout_ms > 0)
1583                 debug3("timeout: %d ms remain after connect", timeout_ms);
1584
1585         /*
1586          * If we successfully made the connection and we have hostbased auth
1587          * enabled, load the public keys so we can later use the ssh-keysign
1588          * helper to sign challenges.
1589          */
1590         sensitive_data.nkeys = 0;
1591         sensitive_data.keys = NULL;
1592         if (options.hostbased_authentication) {
1593                 sensitive_data.nkeys = 10;
1594                 sensitive_data.keys = xcalloc(sensitive_data.nkeys,
1595                     sizeof(struct sshkey));
1596
1597                 /* XXX check errors? */
1598 #define L_PUBKEY(p,o) do { \
1599         if ((o) >= sensitive_data.nkeys) \
1600                 fatal_f("pubkey out of array bounds"); \
1601         check_load(sshkey_load_public(p, &(sensitive_data.keys[o]), NULL), \
1602             p, "pubkey"); \
1603 } while (0)
1604 #define L_CERT(p,o) do { \
1605         if ((o) >= sensitive_data.nkeys) \
1606                 fatal_f("cert out of array bounds"); \
1607         check_load(sshkey_load_cert(p, &(sensitive_data.keys[o])), p, "cert"); \
1608 } while (0)
1609
1610                 if (options.hostbased_authentication == 1) {
1611                         L_CERT(_PATH_HOST_ECDSA_KEY_FILE, 0);
1612                         L_CERT(_PATH_HOST_ED25519_KEY_FILE, 1);
1613                         L_CERT(_PATH_HOST_RSA_KEY_FILE, 2);
1614                         L_CERT(_PATH_HOST_DSA_KEY_FILE, 3);
1615                         L_PUBKEY(_PATH_HOST_ECDSA_KEY_FILE, 4);
1616                         L_PUBKEY(_PATH_HOST_ED25519_KEY_FILE, 5);
1617                         L_PUBKEY(_PATH_HOST_RSA_KEY_FILE, 6);
1618                         L_PUBKEY(_PATH_HOST_DSA_KEY_FILE, 7);
1619                         L_CERT(_PATH_HOST_XMSS_KEY_FILE, 8);
1620                         L_PUBKEY(_PATH_HOST_XMSS_KEY_FILE, 9);
1621                 }
1622         }
1623
1624         /* load options.identity_files */
1625         load_public_identity_files(cinfo);
1626
1627         /* optionally set the SSH_AUTHSOCKET_ENV_NAME variable */
1628         if (options.identity_agent &&
1629             strcmp(options.identity_agent, SSH_AUTHSOCKET_ENV_NAME) != 0) {
1630                 if (strcmp(options.identity_agent, "none") == 0) {
1631                         unsetenv(SSH_AUTHSOCKET_ENV_NAME);
1632                 } else {
1633                         cp = options.identity_agent;
1634                         /* legacy (limited) format */
1635                         if (cp[0] == '$' && cp[1] != '{') {
1636                                 if (!valid_env_name(cp + 1)) {
1637                                         fatal("Invalid IdentityAgent "
1638                                             "environment variable name %s", cp);
1639                                 }
1640                                 if ((p = getenv(cp + 1)) == NULL)
1641                                         unsetenv(SSH_AUTHSOCKET_ENV_NAME);
1642                                 else
1643                                         setenv(SSH_AUTHSOCKET_ENV_NAME, p, 1);
1644                         } else {
1645                                 /* identity_agent specifies a path directly */
1646                                 setenv(SSH_AUTHSOCKET_ENV_NAME, cp, 1);
1647                         }
1648                 }
1649         }
1650
1651         if (options.forward_agent && options.forward_agent_sock_path != NULL) {
1652                 cp = options.forward_agent_sock_path;
1653                 if (cp[0] == '$') {
1654                         if (!valid_env_name(cp + 1)) {
1655                                 fatal("Invalid ForwardAgent environment variable name %s", cp);
1656                         }
1657                         if ((p = getenv(cp + 1)) != NULL)
1658                                 forward_agent_sock_path = xstrdup(p);
1659                         else
1660                                 options.forward_agent = 0;
1661                         free(cp);
1662                 } else {
1663                         forward_agent_sock_path = cp;
1664                 }
1665         }
1666
1667         /* Expand ~ in known host file names. */
1668         tilde_expand_paths(options.system_hostfiles,
1669             options.num_system_hostfiles);
1670         tilde_expand_paths(options.user_hostfiles, options.num_user_hostfiles);
1671
1672         ssh_signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */
1673         ssh_signal(SIGCHLD, main_sigchld_handler);
1674
1675         /* Log into the remote system.  Never returns if the login fails. */
1676         ssh_login(ssh, &sensitive_data, host, (struct sockaddr *)&hostaddr,
1677             options.port, pw, timeout_ms, cinfo);
1678
1679         /* We no longer need the private host keys.  Clear them now. */
1680         if (sensitive_data.nkeys != 0) {
1681                 for (i = 0; i < sensitive_data.nkeys; i++) {
1682                         if (sensitive_data.keys[i] != NULL) {
1683                                 /* Destroys contents safely */
1684                                 debug3("clear hostkey %d", i);
1685                                 sshkey_free(sensitive_data.keys[i]);
1686                                 sensitive_data.keys[i] = NULL;
1687                         }
1688                 }
1689                 free(sensitive_data.keys);
1690         }
1691         for (i = 0; i < options.num_identity_files; i++) {
1692                 free(options.identity_files[i]);
1693                 options.identity_files[i] = NULL;
1694                 if (options.identity_keys[i]) {
1695                         sshkey_free(options.identity_keys[i]);
1696                         options.identity_keys[i] = NULL;
1697                 }
1698         }
1699         for (i = 0; i < options.num_certificate_files; i++) {
1700                 free(options.certificate_files[i]);
1701                 options.certificate_files[i] = NULL;
1702         }
1703
1704 #ifdef ENABLE_PKCS11
1705         (void)pkcs11_del_provider(options.pkcs11_provider);
1706 #endif
1707
1708  skip_connect:
1709         exit_status = ssh_session2(ssh, cinfo);
1710         ssh_conn_info_free(cinfo);
1711         ssh_packet_close(ssh);
1712
1713         if (options.control_path != NULL && muxserver_sock != -1)
1714                 unlink(options.control_path);
1715
1716         /* Kill ProxyCommand if it is running. */
1717         ssh_kill_proxy_command();
1718
1719         return exit_status;
1720 }
1721
1722 static void
1723 control_persist_detach(void)
1724 {
1725         pid_t pid;
1726
1727         debug_f("backgrounding master process");
1728
1729         /*
1730          * master (current process) into the background, and make the
1731          * foreground process a client of the backgrounded master.
1732          */
1733         switch ((pid = fork())) {
1734         case -1:
1735                 fatal_f("fork: %s", strerror(errno));
1736         case 0:
1737                 /* Child: master process continues mainloop */
1738                 break;
1739         default:
1740                 /* Parent: set up mux client to connect to backgrounded master */
1741                 debug2_f("background process is %ld", (long)pid);
1742                 options.stdin_null = ostdin_null_flag;
1743                 options.request_tty = orequest_tty;
1744                 tty_flag = otty_flag;
1745                 options.session_type = osession_type;
1746                 close(muxserver_sock);
1747                 muxserver_sock = -1;
1748                 options.control_master = SSHCTL_MASTER_NO;
1749                 muxclient(options.control_path);
1750                 /* muxclient() doesn't return on success. */
1751                 fatal("Failed to connect to new control master");
1752         }
1753         if (stdfd_devnull(1, 1, !(log_is_on_stderr() && debug_flag)) == -1)
1754                 error_f("stdfd_devnull failed");
1755         daemon(1, 1);
1756         setproctitle("%s [mux]", options.control_path);
1757 }
1758
1759 /* Do fork() after authentication. Used by "ssh -f" */
1760 static void
1761 fork_postauth(void)
1762 {
1763         if (need_controlpersist_detach)
1764                 control_persist_detach();
1765         debug("forking to background");
1766         options.fork_after_authentication = 0;
1767         if (daemon(1, 1) == -1)
1768                 fatal("daemon() failed: %.200s", strerror(errno));
1769         if (stdfd_devnull(1, 1, !(log_is_on_stderr() && debug_flag)) == -1)
1770                 error_f("stdfd_devnull failed");
1771 }
1772
1773 static void
1774 forwarding_success(void)
1775 {
1776         if (forward_confirms_pending == -1)
1777                 return;
1778         if (--forward_confirms_pending == 0) {
1779                 debug_f("all expected forwarding replies received");
1780                 if (options.fork_after_authentication)
1781                         fork_postauth();
1782         } else {
1783                 debug2_f("%d expected forwarding replies remaining",
1784                     forward_confirms_pending);
1785         }
1786 }
1787
1788 /* Callback for remote forward global requests */
1789 static void
1790 ssh_confirm_remote_forward(struct ssh *ssh, int type, u_int32_t seq, void *ctxt)
1791 {
1792         struct Forward *rfwd = (struct Forward *)ctxt;
1793         u_int port;
1794         int r;
1795
1796         /* XXX verbose() on failure? */
1797         debug("remote forward %s for: listen %s%s%d, connect %s:%d",
1798             type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure",
1799             rfwd->listen_path ? rfwd->listen_path :
1800             rfwd->listen_host ? rfwd->listen_host : "",
1801             (rfwd->listen_path || rfwd->listen_host) ? ":" : "",
1802             rfwd->listen_port, rfwd->connect_path ? rfwd->connect_path :
1803             rfwd->connect_host, rfwd->connect_port);
1804         if (rfwd->listen_path == NULL && rfwd->listen_port == 0) {
1805                 if (type == SSH2_MSG_REQUEST_SUCCESS) {
1806                         if ((r = sshpkt_get_u32(ssh, &port)) != 0)
1807                                 fatal_fr(r, "parse packet");
1808                         if (port > 65535) {
1809                                 error("Invalid allocated port %u for remote "
1810                                     "forward to %s:%d", port,
1811                                     rfwd->connect_host, rfwd->connect_port);
1812                                 /* Ensure failure processing runs below */
1813                                 type = SSH2_MSG_REQUEST_FAILURE;
1814                                 channel_update_permission(ssh,
1815                                     rfwd->handle, -1);
1816                         } else {
1817                                 rfwd->allocated_port = (int)port;
1818                                 logit("Allocated port %u for remote "
1819                                     "forward to %s:%d",
1820                                     rfwd->allocated_port, rfwd->connect_host,
1821                                     rfwd->connect_port);
1822                                 channel_update_permission(ssh,
1823                                     rfwd->handle, rfwd->allocated_port);
1824                         }
1825                 } else {
1826                         channel_update_permission(ssh, rfwd->handle, -1);
1827                 }
1828         }
1829
1830         if (type == SSH2_MSG_REQUEST_FAILURE) {
1831                 if (options.exit_on_forward_failure) {
1832                         if (rfwd->listen_path != NULL)
1833                                 fatal("Error: remote port forwarding failed "
1834                                     "for listen path %s", rfwd->listen_path);
1835                         else
1836                                 fatal("Error: remote port forwarding failed "
1837                                     "for listen port %d", rfwd->listen_port);
1838                 } else {
1839                         if (rfwd->listen_path != NULL)
1840                                 logit("Warning: remote port forwarding failed "
1841                                     "for listen path %s", rfwd->listen_path);
1842                         else
1843                                 logit("Warning: remote port forwarding failed "
1844                                     "for listen port %d", rfwd->listen_port);
1845                 }
1846         }
1847         forwarding_success();
1848 }
1849
1850 static void
1851 client_cleanup_stdio_fwd(struct ssh *ssh, int id, void *arg)
1852 {
1853         debug("stdio forwarding: done");
1854         cleanup_exit(0);
1855 }
1856
1857 static void
1858 ssh_stdio_confirm(struct ssh *ssh, int id, int success, void *arg)
1859 {
1860         if (!success)
1861                 fatal("stdio forwarding failed");
1862 }
1863
1864 static void
1865 ssh_tun_confirm(struct ssh *ssh, int id, int success, void *arg)
1866 {
1867         if (!success) {
1868                 error("Tunnel forwarding failed");
1869                 if (options.exit_on_forward_failure)
1870                         cleanup_exit(255);
1871         }
1872
1873         debug_f("tunnel forward established, id=%d", id);
1874         forwarding_success();
1875 }
1876
1877 static void
1878 ssh_init_stdio_forwarding(struct ssh *ssh)
1879 {
1880         Channel *c;
1881         int in, out;
1882
1883         if (options.stdio_forward_host == NULL)
1884                 return;
1885
1886         debug3_f("%s:%d", options.stdio_forward_host,
1887             options.stdio_forward_port);
1888
1889         if ((in = dup(STDIN_FILENO)) == -1 ||
1890             (out = dup(STDOUT_FILENO)) == -1)
1891                 fatal_f("dup() in/out failed");
1892         if ((c = channel_connect_stdio_fwd(ssh, options.stdio_forward_host,
1893             options.stdio_forward_port, in, out,
1894             CHANNEL_NONBLOCK_STDIO)) == NULL)
1895                 fatal_f("channel_connect_stdio_fwd failed");
1896         channel_register_cleanup(ssh, c->self, client_cleanup_stdio_fwd, 0);
1897         channel_register_open_confirm(ssh, c->self, ssh_stdio_confirm, NULL);
1898 }
1899
1900 static void
1901 ssh_init_forward_permissions(struct ssh *ssh, const char *what, char **opens,
1902     u_int num_opens)
1903 {
1904         u_int i;
1905         int port;
1906         char *addr, *arg, *oarg, ch;
1907         int where = FORWARD_LOCAL;
1908
1909         channel_clear_permission(ssh, FORWARD_ADM, where);
1910         if (num_opens == 0)
1911                 return; /* permit any */
1912
1913         /* handle keywords: "any" / "none" */
1914         if (num_opens == 1 && strcmp(opens[0], "any") == 0)
1915                 return;
1916         if (num_opens == 1 && strcmp(opens[0], "none") == 0) {
1917                 channel_disable_admin(ssh, where);
1918                 return;
1919         }
1920         /* Otherwise treat it as a list of permitted host:port */
1921         for (i = 0; i < num_opens; i++) {
1922                 oarg = arg = xstrdup(opens[i]);
1923                 ch = '\0';
1924                 addr = hpdelim2(&arg, &ch);
1925                 if (addr == NULL || ch == '/')
1926                         fatal_f("missing host in %s", what);
1927                 addr = cleanhostname(addr);
1928                 if (arg == NULL || ((port = permitopen_port(arg)) < 0))
1929                         fatal_f("bad port number in %s", what);
1930                 /* Send it to channels layer */
1931                 channel_add_permission(ssh, FORWARD_ADM,
1932                     where, addr, port);
1933                 free(oarg);
1934         }
1935 }
1936
1937 static void
1938 ssh_init_forwarding(struct ssh *ssh, char **ifname)
1939 {
1940         int success = 0;
1941         int i;
1942
1943         ssh_init_forward_permissions(ssh, "permitremoteopen",
1944             options.permitted_remote_opens,
1945             options.num_permitted_remote_opens);
1946
1947         if (options.exit_on_forward_failure)
1948                 forward_confirms_pending = 0; /* track pending requests */
1949         /* Initiate local TCP/IP port forwardings. */
1950         for (i = 0; i < options.num_local_forwards; i++) {
1951                 debug("Local connections to %.200s:%d forwarded to remote "
1952                     "address %.200s:%d",
1953                     (options.local_forwards[i].listen_path != NULL) ?
1954                     options.local_forwards[i].listen_path :
1955                     (options.local_forwards[i].listen_host == NULL) ?
1956                     (options.fwd_opts.gateway_ports ? "*" : "LOCALHOST") :
1957                     options.local_forwards[i].listen_host,
1958                     options.local_forwards[i].listen_port,
1959                     (options.local_forwards[i].connect_path != NULL) ?
1960                     options.local_forwards[i].connect_path :
1961                     options.local_forwards[i].connect_host,
1962                     options.local_forwards[i].connect_port);
1963                 success += channel_setup_local_fwd_listener(ssh,
1964                     &options.local_forwards[i], &options.fwd_opts);
1965         }
1966         if (i > 0 && success != i && options.exit_on_forward_failure)
1967                 fatal("Could not request local forwarding.");
1968         if (i > 0 && success == 0)
1969                 error("Could not request local forwarding.");
1970
1971         /* Initiate remote TCP/IP port forwardings. */
1972         for (i = 0; i < options.num_remote_forwards; i++) {
1973                 debug("Remote connections from %.200s:%d forwarded to "
1974                     "local address %.200s:%d",
1975                     (options.remote_forwards[i].listen_path != NULL) ?
1976                     options.remote_forwards[i].listen_path :
1977                     (options.remote_forwards[i].listen_host == NULL) ?
1978                     "LOCALHOST" : options.remote_forwards[i].listen_host,
1979                     options.remote_forwards[i].listen_port,
1980                     (options.remote_forwards[i].connect_path != NULL) ?
1981                     options.remote_forwards[i].connect_path :
1982                     options.remote_forwards[i].connect_host,
1983                     options.remote_forwards[i].connect_port);
1984                 if ((options.remote_forwards[i].handle =
1985                     channel_request_remote_forwarding(ssh,
1986                     &options.remote_forwards[i])) >= 0) {
1987                         client_register_global_confirm(
1988                             ssh_confirm_remote_forward,
1989                             &options.remote_forwards[i]);
1990                         forward_confirms_pending++;
1991                 } else if (options.exit_on_forward_failure)
1992                         fatal("Could not request remote forwarding.");
1993                 else
1994                         logit("Warning: Could not request remote forwarding.");
1995         }
1996
1997         /* Initiate tunnel forwarding. */
1998         if (options.tun_open != SSH_TUNMODE_NO) {
1999                 if ((*ifname = client_request_tun_fwd(ssh,
2000                     options.tun_open, options.tun_local,
2001                     options.tun_remote, ssh_tun_confirm, NULL)) != NULL)
2002                         forward_confirms_pending++;
2003                 else if (options.exit_on_forward_failure)
2004                         fatal("Could not request tunnel forwarding.");
2005                 else
2006                         error("Could not request tunnel forwarding.");
2007         }
2008         if (forward_confirms_pending > 0) {
2009                 debug_f("expecting replies for %d forwards",
2010                     forward_confirms_pending);
2011         }
2012 }
2013
2014 static void
2015 check_agent_present(void)
2016 {
2017         int r;
2018
2019         if (options.forward_agent) {
2020                 /* Clear agent forwarding if we don't have an agent. */
2021                 if ((r = ssh_get_authentication_socket(NULL)) != 0) {
2022                         options.forward_agent = 0;
2023                         if (r != SSH_ERR_AGENT_NOT_PRESENT)
2024                                 debug_r(r, "ssh_get_authentication_socket");
2025                 }
2026         }
2027 }
2028
2029 static void
2030 ssh_session2_setup(struct ssh *ssh, int id, int success, void *arg)
2031 {
2032         extern char **environ;
2033         const char *display, *term;
2034         int r, interactive = tty_flag;
2035         char *proto = NULL, *data = NULL;
2036
2037         if (!success)
2038                 return; /* No need for error message, channels code sens one */
2039
2040         display = getenv("DISPLAY");
2041         if (display == NULL && options.forward_x11)
2042                 debug("X11 forwarding requested but DISPLAY not set");
2043         if (options.forward_x11 && client_x11_get_proto(ssh, display,
2044             options.xauth_location, options.forward_x11_trusted,
2045             options.forward_x11_timeout, &proto, &data) == 0) {
2046                 /* Request forwarding with authentication spoofing. */
2047                 debug("Requesting X11 forwarding with authentication "
2048                     "spoofing.");
2049                 x11_request_forwarding_with_spoofing(ssh, id, display, proto,
2050                     data, 1);
2051                 client_expect_confirm(ssh, id, "X11 forwarding", CONFIRM_WARN);
2052                 /* XXX exit_on_forward_failure */
2053                 interactive = 1;
2054         }
2055
2056         check_agent_present();
2057         if (options.forward_agent) {
2058                 debug("Requesting authentication agent forwarding.");
2059                 channel_request_start(ssh, id, "auth-agent-req@openssh.com", 0);
2060                 if ((r = sshpkt_send(ssh)) != 0)
2061                         fatal_fr(r, "send packet");
2062         }
2063
2064         /* Tell the packet module whether this is an interactive session. */
2065         ssh_packet_set_interactive(ssh, interactive,
2066             options.ip_qos_interactive, options.ip_qos_bulk);
2067
2068         if ((term = lookup_env_in_list("TERM", options.setenv,
2069             options.num_setenv)) == NULL || *term == '\0')
2070                 term = getenv("TERM");
2071         client_session2_setup(ssh, id, tty_flag,
2072             options.session_type == SESSION_TYPE_SUBSYSTEM, term,
2073             NULL, fileno(stdin), command, environ);
2074 }
2075
2076 /* open new channel for a session */
2077 static int
2078 ssh_session2_open(struct ssh *ssh)
2079 {
2080         Channel *c;
2081         int window, packetmax, in, out, err;
2082
2083         if (options.stdin_null) {
2084                 in = open(_PATH_DEVNULL, O_RDONLY);
2085         } else {
2086                 in = dup(STDIN_FILENO);
2087         }
2088         out = dup(STDOUT_FILENO);
2089         err = dup(STDERR_FILENO);
2090
2091         if (in == -1 || out == -1 || err == -1)
2092                 fatal("dup() in/out/err failed");
2093
2094         window = CHAN_SES_WINDOW_DEFAULT;
2095         packetmax = CHAN_SES_PACKET_DEFAULT;
2096         if (tty_flag) {
2097                 window >>= 1;
2098                 packetmax >>= 1;
2099         }
2100         c = channel_new(ssh,
2101             "session", SSH_CHANNEL_OPENING, in, out, err,
2102             window, packetmax, CHAN_EXTENDED_WRITE,
2103             "client-session", CHANNEL_NONBLOCK_STDIO);
2104
2105         debug3_f("channel_new: %d", c->self);
2106
2107         channel_send_open(ssh, c->self);
2108         if (options.session_type != SESSION_TYPE_NONE)
2109                 channel_register_open_confirm(ssh, c->self,
2110                     ssh_session2_setup, NULL);
2111
2112         return c->self;
2113 }
2114
2115 static int
2116 ssh_session2(struct ssh *ssh, const struct ssh_conn_info *cinfo)
2117 {
2118         int r, id = -1;
2119         char *cp, *tun_fwd_ifname = NULL;
2120
2121         /* XXX should be pre-session */
2122         if (!options.control_persist)
2123                 ssh_init_stdio_forwarding(ssh);
2124
2125         ssh_init_forwarding(ssh, &tun_fwd_ifname);
2126
2127         if (options.local_command != NULL) {
2128                 debug3("expanding LocalCommand: %s", options.local_command);
2129                 cp = options.local_command;
2130                 options.local_command = percent_expand(cp,
2131                     DEFAULT_CLIENT_PERCENT_EXPAND_ARGS(cinfo),
2132                     "T", tun_fwd_ifname == NULL ? "NONE" : tun_fwd_ifname,
2133                     (char *)NULL);
2134                 debug3("expanded LocalCommand: %s", options.local_command);
2135                 free(cp);
2136         }
2137
2138         /* Start listening for multiplex clients */
2139         if (!ssh_packet_get_mux(ssh))
2140                 muxserver_listen(ssh);
2141
2142         /*
2143          * If we are in control persist mode and have a working mux listen
2144          * socket, then prepare to background ourselves and have a foreground
2145          * client attach as a control client.
2146          * NB. we must save copies of the flags that we override for
2147          * the backgrounding, since we defer attachment of the client until
2148          * after the connection is fully established (in particular,
2149          * async rfwd replies have been received for ExitOnForwardFailure).
2150          */
2151         if (options.control_persist && muxserver_sock != -1) {
2152                 ostdin_null_flag = options.stdin_null;
2153                 osession_type = options.session_type;
2154                 orequest_tty = options.request_tty;
2155                 otty_flag = tty_flag;
2156                 options.stdin_null = 1;
2157                 options.session_type = SESSION_TYPE_NONE;
2158                 tty_flag = 0;
2159                 if (!options.fork_after_authentication &&
2160                     (osession_type != SESSION_TYPE_NONE ||
2161                     options.stdio_forward_host != NULL))
2162                         need_controlpersist_detach = 1;
2163                 options.fork_after_authentication = 1;
2164         }
2165         /*
2166          * ControlPersist mux listen socket setup failed, attempt the
2167          * stdio forward setup that we skipped earlier.
2168          */
2169         if (options.control_persist && muxserver_sock == -1)
2170                 ssh_init_stdio_forwarding(ssh);
2171
2172         if (options.session_type != SESSION_TYPE_NONE)
2173                 id = ssh_session2_open(ssh);
2174         else {
2175                 ssh_packet_set_interactive(ssh,
2176                     options.control_master == SSHCTL_MASTER_NO,
2177                     options.ip_qos_interactive, options.ip_qos_bulk);
2178         }
2179
2180         /* If we don't expect to open a new session, then disallow it */
2181         if (options.control_master == SSHCTL_MASTER_NO &&
2182             (ssh->compat & SSH_NEW_OPENSSH)) {
2183                 debug("Requesting no-more-sessions@openssh.com");
2184                 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 ||
2185                     (r = sshpkt_put_cstring(ssh,
2186                     "no-more-sessions@openssh.com")) != 0 ||
2187                     (r = sshpkt_put_u8(ssh, 0)) != 0 ||
2188                     (r = sshpkt_send(ssh)) != 0)
2189                         fatal_fr(r, "send packet");
2190         }
2191
2192         /* Execute a local command */
2193         if (options.local_command != NULL &&
2194             options.permit_local_command)
2195                 ssh_local_cmd(options.local_command);
2196
2197         /*
2198          * stdout is now owned by the session channel; clobber it here
2199          * so future channel closes are propagated to the local fd.
2200          * NB. this can only happen after LocalCommand has completed,
2201          * as it may want to write to stdout.
2202          */
2203         if (!need_controlpersist_detach && stdfd_devnull(0, 1, 0) == -1)
2204                 error_f("stdfd_devnull failed");
2205
2206         /*
2207          * If requested and we are not interested in replies to remote
2208          * forwarding requests, then let ssh continue in the background.
2209          */
2210         if (options.fork_after_authentication) {
2211                 if (options.exit_on_forward_failure &&
2212                     options.num_remote_forwards > 0) {
2213                         debug("deferring postauth fork until remote forward "
2214                             "confirmation received");
2215                 } else
2216                         fork_postauth();
2217         }
2218
2219         return client_loop(ssh, tty_flag, tty_flag ?
2220             options.escape_char : SSH_ESCAPECHAR_NONE, id);
2221 }
2222
2223 /* Loads all IdentityFile and CertificateFile keys */
2224 static void
2225 load_public_identity_files(const struct ssh_conn_info *cinfo)
2226 {
2227         char *filename, *cp;
2228         struct sshkey *public;
2229         int i;
2230         u_int n_ids, n_certs;
2231         char *identity_files[SSH_MAX_IDENTITY_FILES];
2232         struct sshkey *identity_keys[SSH_MAX_IDENTITY_FILES];
2233         int identity_file_userprovided[SSH_MAX_IDENTITY_FILES];
2234         char *certificate_files[SSH_MAX_CERTIFICATE_FILES];
2235         struct sshkey *certificates[SSH_MAX_CERTIFICATE_FILES];
2236         int certificate_file_userprovided[SSH_MAX_CERTIFICATE_FILES];
2237 #ifdef ENABLE_PKCS11
2238         struct sshkey **keys = NULL;
2239         char **comments = NULL;
2240         int nkeys;
2241 #endif /* PKCS11 */
2242
2243         n_ids = n_certs = 0;
2244         memset(identity_files, 0, sizeof(identity_files));
2245         memset(identity_keys, 0, sizeof(identity_keys));
2246         memset(identity_file_userprovided, 0,
2247             sizeof(identity_file_userprovided));
2248         memset(certificate_files, 0, sizeof(certificate_files));
2249         memset(certificates, 0, sizeof(certificates));
2250         memset(certificate_file_userprovided, 0,
2251             sizeof(certificate_file_userprovided));
2252
2253 #ifdef ENABLE_PKCS11
2254         if (options.pkcs11_provider != NULL &&
2255             options.num_identity_files < SSH_MAX_IDENTITY_FILES &&
2256             (pkcs11_init(!options.batch_mode) == 0) &&
2257             (nkeys = pkcs11_add_provider(options.pkcs11_provider, NULL,
2258             &keys, &comments)) > 0) {
2259                 for (i = 0; i < nkeys; i++) {
2260                         if (n_ids >= SSH_MAX_IDENTITY_FILES) {
2261                                 sshkey_free(keys[i]);
2262                                 free(comments[i]);
2263                                 continue;
2264                         }
2265                         identity_keys[n_ids] = keys[i];
2266                         identity_files[n_ids] = comments[i]; /* transferred */
2267                         n_ids++;
2268                 }
2269                 free(keys);
2270                 free(comments);
2271         }
2272 #endif /* ENABLE_PKCS11 */
2273         for (i = 0; i < options.num_identity_files; i++) {
2274                 if (n_ids >= SSH_MAX_IDENTITY_FILES ||
2275                     strcasecmp(options.identity_files[i], "none") == 0) {
2276                         free(options.identity_files[i]);
2277                         options.identity_files[i] = NULL;
2278                         continue;
2279                 }
2280                 cp = tilde_expand_filename(options.identity_files[i], getuid());
2281                 filename = default_client_percent_dollar_expand(cp, cinfo);
2282                 free(cp);
2283                 check_load(sshkey_load_public(filename, &public, NULL),
2284                     filename, "pubkey");
2285                 debug("identity file %s type %d", filename,
2286                     public ? public->type : -1);
2287                 free(options.identity_files[i]);
2288                 identity_files[n_ids] = filename;
2289                 identity_keys[n_ids] = public;
2290                 identity_file_userprovided[n_ids] =
2291                     options.identity_file_userprovided[i];
2292                 if (++n_ids >= SSH_MAX_IDENTITY_FILES)
2293                         continue;
2294
2295                 /*
2296                  * If no certificates have been explicitly listed then try
2297                  * to add the default certificate variant too.
2298                  */
2299                 if (options.num_certificate_files != 0)
2300                         continue;
2301                 xasprintf(&cp, "%s-cert", filename);
2302                 check_load(sshkey_load_public(cp, &public, NULL),
2303                     filename, "pubkey");
2304                 debug("identity file %s type %d", cp,
2305                     public ? public->type : -1);
2306                 if (public == NULL) {
2307                         free(cp);
2308                         continue;
2309                 }
2310                 if (!sshkey_is_cert(public)) {
2311                         debug_f("key %s type %s is not a certificate",
2312                             cp, sshkey_type(public));
2313                         sshkey_free(public);
2314                         free(cp);
2315                         continue;
2316                 }
2317                 /* NB. leave filename pointing to private key */
2318                 identity_files[n_ids] = xstrdup(filename);
2319                 identity_keys[n_ids] = public;
2320                 identity_file_userprovided[n_ids] =
2321                     options.identity_file_userprovided[i];
2322                 n_ids++;
2323         }
2324
2325         if (options.num_certificate_files > SSH_MAX_CERTIFICATE_FILES)
2326                 fatal_f("too many certificates");
2327         for (i = 0; i < options.num_certificate_files; i++) {
2328                 cp = tilde_expand_filename(options.certificate_files[i],
2329                     getuid());
2330                 filename = default_client_percent_dollar_expand(cp, cinfo);
2331                 free(cp);
2332
2333                 check_load(sshkey_load_public(filename, &public, NULL),
2334                     filename, "certificate");
2335                 debug("certificate file %s type %d", filename,
2336                     public ? public->type : -1);
2337                 free(options.certificate_files[i]);
2338                 options.certificate_files[i] = NULL;
2339                 if (public == NULL) {
2340                         free(filename);
2341                         continue;
2342                 }
2343                 if (!sshkey_is_cert(public)) {
2344                         debug_f("key %s type %s is not a certificate",
2345                             filename, sshkey_type(public));
2346                         sshkey_free(public);
2347                         free(filename);
2348                         continue;
2349                 }
2350                 certificate_files[n_certs] = filename;
2351                 certificates[n_certs] = public;
2352                 certificate_file_userprovided[n_certs] =
2353                     options.certificate_file_userprovided[i];
2354                 ++n_certs;
2355         }
2356
2357         options.num_identity_files = n_ids;
2358         memcpy(options.identity_files, identity_files, sizeof(identity_files));
2359         memcpy(options.identity_keys, identity_keys, sizeof(identity_keys));
2360         memcpy(options.identity_file_userprovided,
2361             identity_file_userprovided, sizeof(identity_file_userprovided));
2362
2363         options.num_certificate_files = n_certs;
2364         memcpy(options.certificate_files,
2365             certificate_files, sizeof(certificate_files));
2366         memcpy(options.certificates, certificates, sizeof(certificates));
2367         memcpy(options.certificate_file_userprovided,
2368             certificate_file_userprovided,
2369             sizeof(certificate_file_userprovided));
2370 }
2371
2372 static void
2373 main_sigchld_handler(int sig)
2374 {
2375         int save_errno = errno;
2376         pid_t pid;
2377         int status;
2378
2379         while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
2380             (pid == -1 && errno == EINTR))
2381                 ;
2382         errno = save_errno;
2383 }