crypto/openssh/ssh.c

   1 /* $OpenBSD: ssh.c,v 1.584 2023/01/17 18:52:44 millert Exp $ */
   2 /*
   3  * Author: Tatu Ylonen <ylo@cs.hut.fi>
   4  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
   5  *                    All rights reserved
   6  * Ssh client program.  This program can be used to log into a remote machine.
   7  * The software supports strong authentication, encryption, and forwarding
   8  * of X11, TCP/IP, and authentication connections.
   9  *
  10  * As far as I am concerned, the code I have written for this software
  11  * can be used freely for any purpose.  Any derived versions of this
  12  * software must be clearly marked as such, and if the derived work is
  13  * incompatible with the protocol description in the RFC file, it must be
  14  * called by a name other than "ssh" or "Secure Shell".
  15  *
  16  * Copyright (c) 1999 Niels Provos.  All rights reserved.
  17  * Copyright (c) 2000, 2001, 2002, 2003 Markus Friedl.  All rights reserved.
  18  *
  19  * Modified to work with SSLeay by Niels Provos <provos@citi.umich.edu>
  20  * in Canada (German citizen).
  21  *
  22  * Redistribution and use in source and binary forms, with or without
  23  * modification, are permitted provided that the following conditions
  24  * are met:
  25  * 1. Redistributions of source code must retain the above copyright
  26  *    notice, this list of conditions and the following disclaimer.
  27  * 2. Redistributions in binary form must reproduce the above copyright
  28  *    notice, this list of conditions and the following disclaimer in the
  29  *    documentation and/or other materials provided with the distribution.
  30  *
  31  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  32  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  33  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  34  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  35  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  36  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  37  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  38  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  39  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  40  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  41  */
  42
  43 #include "includes.h"
  44
  45 #include <sys/types.h>
  46 #ifdef HAVE_SYS_STAT_H
  47 # include <sys/stat.h>
  48 #endif
  49 #include <sys/resource.h>
  50 #include <sys/ioctl.h>
  51 #include <sys/socket.h>
  52 #include <sys/wait.h>
  53
  54 #include <ctype.h>
  55 #include <errno.h>
  56 #include <fcntl.h>
  57 #include <netdb.h>
  58 #ifdef HAVE_PATHS_H
  59 #include <paths.h>
  60 #endif
  61 #include <pwd.h>
  62 #include <signal.h>
  63 #include <stdarg.h>
  64 #include <stddef.h>
  65 #include <stdio.h>
  66 #include <stdlib.h>
  67 #include <string.h>
  68 #include <stdarg.h>
  69 #include <unistd.h>
  70 #include <limits.h>
  71 #include <locale.h>
  72
  73 #include <netinet/in.h>
  74 #include <arpa/inet.h>
  75
  76 #ifdef WITH_OPENSSL
  77 #include <openssl/evp.h>
  78 #include <openssl/err.h>
  79 #endif
  80 #include "openbsd-compat/openssl-compat.h"
  81 #include "openbsd-compat/sys-queue.h"
  82
  83 #include "xmalloc.h"
  84 #include "ssh.h"
  85 #include "ssh2.h"
  86 #include "canohost.h"
  87 #include "compat.h"
  88 #include "cipher.h"
  89 #include "packet.h"
  90 #include "sshbuf.h"
  91 #include "channels.h"
  92 #include "sshkey.h"
  93 #include "authfd.h"
  94 #include "authfile.h"
  95 #include "pathnames.h"
  96 #include "dispatch.h"
  97 #include "clientloop.h"
  98 #include "log.h"
  99 #include "misc.h"
 100 #include "readconf.h"
 101 #include "sshconnect.h"
 102 #include "kex.h"
 103 #include "mac.h"
 104 #include "sshpty.h"
 105 #include "match.h"
 106 #include "msg.h"
 107 #include "version.h"
 108 #include "ssherr.h"
 109 #include "myproposal.h"
 110 #include "utf8.h"
 111
 112 #ifdef ENABLE_PKCS11
 113 #include "ssh-pkcs11.h"
 114 #endif
 115
 116 extern char *__progname;
 117
 118 /* Saves a copy of argv for setproctitle emulation */
 119 #ifndef HAVE_SETPROCTITLE
 120 static char **saved_av;
 121 #endif
 122
 123 /* Flag indicating whether debug mode is on.  May be set on the command line. */
 124 int debug_flag = 0;
 125
 126 /* Flag indicating whether a tty should be requested */
 127 int tty_flag = 0;
 128
 129 /*
 130  * Flag indicating that the current process should be backgrounded and
 131  * a new mux-client launched in the foreground for ControlPersist.
 132  */
 133 int need_controlpersist_detach = 0;
 134
 135 /* Copies of flags for ControlPersist foreground mux-client */
 136 int ostdin_null_flag, osession_type, otty_flag, orequest_tty;
 137
 138 /*
 139  * General data structure for command line options and options configurable
 140  * in configuration files.  See readconf.h.
 141  */
 142 Options options;
 143
 144 /* optional user configfile */
 145 char *config = NULL;
 146
 147 /*
 148  * Name of the host we are connecting to.  This is the name given on the
 149  * command line, or the Hostname specified for the user-supplied name in a
 150  * configuration file.
 151  */
 152 char *host;
 153
 154 /*
 155  * A config can specify a path to forward, overriding SSH_AUTH_SOCK. If this is
 156  * not NULL, forward the socket at this path instead.
 157  */
 158 char *forward_agent_sock_path = NULL;
 159
 160 /* socket address the host resolves to */
 161 struct sockaddr_storage hostaddr;
 162
 163 /* Private host keys. */
 164 Sensitive sensitive_data;
 165
 166 /* command to be executed */
 167 struct sshbuf *command;
 168
 169 /* # of replies received for global requests */
 170 static int forward_confirms_pending = -1;
 171
 172 /* mux.c */
 173 extern int muxserver_sock;
 174 extern u_int muxclient_command;
 175
 176 /* Prints a help message to the user.  This function never returns. */
 177
 178 static void
 179 usage(void)
 180 {
 181         fprintf(stderr,
 182 "usage: ssh [-46AaCfGgKkMNnqsTtVvXxYy] [-B bind_interface]\n"
 183 "           [-b bind_address] [-c cipher_spec] [-D [bind_address:]port]\n"
 184 "           [-E log_file] [-e escape_char] [-F configfile] [-I pkcs11]\n"
 185 "           [-i identity_file] [-J [user@]host[:port]] [-L address]\n"
 186 "           [-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port]\n"
 187 "           [-Q query_option] [-R address] [-S ctl_path] [-W host:port]\n"
 188 "           [-w local_tun[:remote_tun]] destination [command [argument ...]]\n"
 189         );
 190         exit(255);
 191 }
 192
 193 static int ssh_session2(struct ssh *, const struct ssh_conn_info *);
 194 static void load_public_identity_files(const struct ssh_conn_info *);
 195 static void main_sigchld_handler(int);
 196
 197 /* ~/ expand a list of paths. NB. assumes path[n] is heap-allocated. */
 198 static void
 199 tilde_expand_paths(char **paths, u_int num_paths)
 200 {
 201         u_int i;
 202         char *cp;
 203
 204         for (i = 0; i < num_paths; i++) {
 205                 cp = tilde_expand_filename(paths[i], getuid());
 206                 free(paths[i]);
 207                 paths[i] = cp;
 208         }
 209 }
 210
 211 /*
 212  * Expands the set of percent_expand options used by the majority of keywords
 213  * in the client that support percent expansion.
 214  * Caller must free returned string.
 215  */
 216 static char *
 217 default_client_percent_expand(const char *str,
 218     const struct ssh_conn_info *cinfo)
 219 {
 220         return percent_expand(str,
 221             DEFAULT_CLIENT_PERCENT_EXPAND_ARGS(cinfo),
 222             (char *)NULL);
 223 }
 224
 225 /*
 226  * Expands the set of percent_expand options used by the majority of keywords
 227  * AND perform environment variable substitution.
 228  * Caller must free returned string.
 229  */
 230 static char *
 231 default_client_percent_dollar_expand(const char *str,
 232     const struct ssh_conn_info *cinfo)
 233 {
 234         char *ret;
 235
 236         ret = percent_dollar_expand(str,
 237             DEFAULT_CLIENT_PERCENT_EXPAND_ARGS(cinfo),
 238             (char *)NULL);
 239         if (ret == NULL)
 240                 fatal("invalid environment variable expansion");
 241         return ret;
 242 }
 243
 244 /*
 245  * Attempt to resolve a host name / port to a set of addresses and
 246  * optionally return any CNAMEs encountered along the way.
 247  * Returns NULL on failure.
 248  * NB. this function must operate with a options having undefined members.
 249  */
 250 static struct addrinfo *
 251 resolve_host(const char *name, int port, int logerr, char *cname, size_t clen)
 252 {
 253         char strport[NI_MAXSERV];
 254         const char *errstr = NULL;
 255         struct addrinfo hints, *res;
 256         int gaierr;
 257         LogLevel loglevel = SYSLOG_LEVEL_DEBUG1;
 258
 259         if (port <= 0)
 260                 port = default_ssh_port();
 261         if (cname != NULL)
 262                 *cname = '\0';
 263         debug3_f("lookup %s:%d", name, port);
 264
 265         snprintf(strport, sizeof strport, "%d", port);
 266         memset(&hints, 0, sizeof(hints));
 267         hints.ai_family = options.address_family == -1 ?
 268             AF_UNSPEC : options.address_family;
 269         hints.ai_socktype = SOCK_STREAM;
 270         if (cname != NULL)
 271                 hints.ai_flags = AI_CANONNAME;
 272         if ((gaierr = getaddrinfo(name, strport, &hints, &res)) != 0) {
 273                 if (logerr || (gaierr != EAI_NONAME && gaierr != EAI_NODATA))
 274                         loglevel = SYSLOG_LEVEL_ERROR;
 275                 do_log2(loglevel, "%s: Could not resolve hostname %.100s: %s",
 276                     __progname, name, ssh_gai_strerror(gaierr));
 277                 return NULL;
 278         }
 279         if (cname != NULL && res->ai_canonname != NULL) {
 280                 if (!valid_domain(res->ai_canonname, 0, &errstr)) {
 281                         error("ignoring bad CNAME \"%s\" for host \"%s\": %s",
 282                             res->ai_canonname, name, errstr);
 283                 } else if (strlcpy(cname, res->ai_canonname, clen) >= clen) {
 284                         error_f("host \"%s\" cname \"%s\" too long (max %lu)",
 285                             name,  res->ai_canonname, (u_long)clen);
 286                         if (clen > 0)
 287                                 *cname = '\0';
 288                 }
 289         }
 290         return res;
 291 }
 292
 293 /* Returns non-zero if name can only be an address and not a hostname */
 294 static int
 295 is_addr_fast(const char *name)
 296 {
 297         return (strchr(name, '%') != NULL || strchr(name, ':') != NULL ||
 298             strspn(name, "0123456789.") == strlen(name));
 299 }
 300
 301 /* Returns non-zero if name represents a valid, single address */
 302 static int
 303 is_addr(const char *name)
 304 {
 305         char strport[NI_MAXSERV];
 306         struct addrinfo hints, *res;
 307
 308         if (is_addr_fast(name))
 309                 return 1;
 310
 311         snprintf(strport, sizeof strport, "%u", default_ssh_port());
 312         memset(&hints, 0, sizeof(hints));
 313         hints.ai_family = options.address_family == -1 ?
 314             AF_UNSPEC : options.address_family;
 315         hints.ai_socktype = SOCK_STREAM;
 316         hints.ai_flags = AI_NUMERICHOST|AI_NUMERICSERV;
 317         if (getaddrinfo(name, strport, &hints, &res) != 0)
 318                 return 0;
 319         if (res == NULL || res->ai_next != NULL) {
 320                 freeaddrinfo(res);
 321                 return 0;
 322         }
 323         freeaddrinfo(res);
 324         return 1;
 325 }
 326
 327 /*
 328  * Attempt to resolve a numeric host address / port to a single address.
 329  * Returns a canonical address string.
 330  * Returns NULL on failure.
 331  * NB. this function must operate with a options having undefined members.
 332  */
 333 static struct addrinfo *
 334 resolve_addr(const char *name, int port, char *caddr, size_t clen)
 335 {
 336         char addr[NI_MAXHOST], strport[NI_MAXSERV];
 337         struct addrinfo hints, *res;
 338         int gaierr;
 339
 340         if (port <= 0)
 341                 port = default_ssh_port();
 342         snprintf(strport, sizeof strport, "%u", port);
 343         memset(&hints, 0, sizeof(hints));
 344         hints.ai_family = options.address_family == -1 ?
 345             AF_UNSPEC : options.address_family;
 346         hints.ai_socktype = SOCK_STREAM;
 347         hints.ai_flags = AI_NUMERICHOST|AI_NUMERICSERV;
 348         if ((gaierr = getaddrinfo(name, strport, &hints, &res)) != 0) {
 349                 debug2_f("could not resolve name %.100s as address: %s",
 350                     name, ssh_gai_strerror(gaierr));
 351                 return NULL;
 352         }
 353         if (res == NULL) {
 354                 debug_f("getaddrinfo %.100s returned no addresses", name);
 355                 return NULL;
 356         }
 357         if (res->ai_next != NULL) {
 358                 debug_f("getaddrinfo %.100s returned multiple addresses", name);
 359                 goto fail;
 360         }
 361         if ((gaierr = getnameinfo(res->ai_addr, res->ai_addrlen,
 362             addr, sizeof(addr), NULL, 0, NI_NUMERICHOST)) != 0) {
 363                 debug_f("Could not format address for name %.100s: %s",
 364                     name, ssh_gai_strerror(gaierr));
 365                 goto fail;
 366         }
 367         if (strlcpy(caddr, addr, clen) >= clen) {
 368                 error_f("host \"%s\" addr \"%s\" too long (max %lu)",
 369                     name,  addr, (u_long)clen);
 370                 if (clen > 0)
 371                         *caddr = '\0';
 372  fail:
 373                 freeaddrinfo(res);
 374                 return NULL;
 375         }
 376         return res;
 377 }
 378
 379 /*
 380  * Check whether the cname is a permitted replacement for the hostname
 381  * and perform the replacement if it is.
 382  * NB. this function must operate with a options having undefined members.
 383  */
 384 static int
 385 check_follow_cname(int direct, char **namep, const char *cname)
 386 {
 387         int i;
 388         struct allowed_cname *rule;
 389
 390         if (*cname == '\0' || !config_has_permitted_cnames(&options) ||
 391             strcmp(*namep, cname) == 0)
 392                 return 0;
 393         if (options.canonicalize_hostname == SSH_CANONICALISE_NO)
 394                 return 0;
 395         /*
 396          * Don't attempt to canonicalize names that will be interpreted by
 397          * a proxy or jump host unless the user specifically requests so.
 398          */
 399         if (!direct &&
 400             options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS)
 401                 return 0;
 402         debug3_f("check \"%s\" CNAME \"%s\"", *namep, cname);
 403         for (i = 0; i < options.num_permitted_cnames; i++) {
 404                 rule = options.permitted_cnames + i;
 405                 if (match_pattern_list(*namep, rule->source_list, 1) != 1 ||
 406                     match_pattern_list(cname, rule->target_list, 1) != 1)
 407                         continue;
 408                 verbose("Canonicalized DNS aliased hostname "
 409                     "\"%s\" => \"%s\"", *namep, cname);
 410                 free(*namep);
 411                 *namep = xstrdup(cname);
 412                 return 1;
 413         }
 414         return 0;
 415 }
 416
 417 /*
 418  * Attempt to resolve the supplied hostname after applying the user's
 419  * canonicalization rules. Returns the address list for the host or NULL
 420  * if no name was found after canonicalization.
 421  * NB. this function must operate with a options having undefined members.
 422  */
 423 static struct addrinfo *
 424 resolve_canonicalize(char **hostp, int port)
 425 {
 426         int i, direct, ndots;
 427         char *cp, *fullhost, newname[NI_MAXHOST];
 428         struct addrinfo *addrs;
 429
 430         /*
 431          * Attempt to canonicalise addresses, regardless of
 432          * whether hostname canonicalisation was requested
 433          */
 434         if ((addrs = resolve_addr(*hostp, port,
 435             newname, sizeof(newname))) != NULL) {
 436                 debug2_f("hostname %.100s is address", *hostp);
 437                 if (strcasecmp(*hostp, newname) != 0) {
 438                         debug2_f("canonicalised address \"%s\" => \"%s\"",
 439                             *hostp, newname);
 440                         free(*hostp);
 441                         *hostp = xstrdup(newname);
 442                 }
 443                 return addrs;
 444         }
 445
 446         /*
 447          * If this looks like an address but didn't parse as one, it might
 448          * be an address with an invalid interface scope. Skip further
 449          * attempts at canonicalisation.
 450          */
 451         if (is_addr_fast(*hostp)) {
 452                 debug_f("hostname %.100s is an unrecognised address", *hostp);
 453                 return NULL;
 454         }
 455
 456         if (options.canonicalize_hostname == SSH_CANONICALISE_NO)
 457                 return NULL;
 458
 459         /*
 460          * Don't attempt to canonicalize names that will be interpreted by
 461          * a proxy unless the user specifically requests so.
 462          */
 463         direct = option_clear_or_none(options.proxy_command) &&
 464             options.jump_host == NULL;
 465         if (!direct &&
 466             options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS)
 467                 return NULL;
 468
 469         /* If domain name is anchored, then resolve it now */
 470         if ((*hostp)[strlen(*hostp) - 1] == '.') {
 471                 debug3_f("name is fully qualified");
 472                 fullhost = xstrdup(*hostp);
 473                 if ((addrs = resolve_host(fullhost, port, 0,
 474                     newname, sizeof(newname))) != NULL)
 475                         goto found;
 476                 free(fullhost);
 477                 goto notfound;
 478         }
 479
 480         /* Don't apply canonicalization to sufficiently-qualified hostnames */
 481         ndots = 0;
 482         for (cp = *hostp; *cp != '\0'; cp++) {
 483                 if (*cp == '.')
 484                         ndots++;
 485         }
 486         if (ndots > options.canonicalize_max_dots) {
 487                 debug3_f("not canonicalizing hostname \"%s\" (max dots %d)",
 488                     *hostp, options.canonicalize_max_dots);
 489                 return NULL;
 490         }
 491         /* Attempt each supplied suffix */
 492         for (i = 0; i < options.num_canonical_domains; i++) {
 493                 if (strcasecmp(options.canonical_domains[i], "none") == 0)
 494                         break;
 495                 xasprintf(&fullhost, "%s.%s.", *hostp,
 496                     options.canonical_domains[i]);
 497                 debug3_f("attempting \"%s\" => \"%s\"", *hostp, fullhost);
 498                 if ((addrs = resolve_host(fullhost, port, 0,
 499                     newname, sizeof(newname))) == NULL) {
 500                         free(fullhost);
 501                         continue;
 502                 }
 503  found:
 504                 /* Remove trailing '.' */
 505                 fullhost[strlen(fullhost) - 1] = '\0';
 506                 /* Follow CNAME if requested */
 507                 if (!check_follow_cname(direct, &fullhost, newname)) {
 508                         debug("Canonicalized hostname \"%s\" => \"%s\"",
 509                             *hostp, fullhost);
 510                 }
 511                 free(*hostp);
 512                 *hostp = fullhost;
 513                 return addrs;
 514         }
 515  notfound:
 516         if (!options.canonicalize_fallback_local)
 517                 fatal("%s: Could not resolve host \"%s\"", __progname, *hostp);
 518         debug2_f("host %s not found in any suffix", *hostp);
 519         return NULL;
 520 }
 521
 522 /*
 523  * Check the result of hostkey loading, ignoring some errors and either
 524  * discarding the key or fatal()ing for others.
 525  */
 526 static void
 527 check_load(int r, struct sshkey **k, const char *path, const char *message)
 528 {
 529         switch (r) {
 530         case 0:
 531                 /* Check RSA keys size and discard if undersized */
 532                 if (k != NULL && *k != NULL &&
 533                     (r = sshkey_check_rsa_length(*k,
 534                     options.required_rsa_size)) != 0) {
 535                         error_r(r, "load %s \"%s\"", message, path);
 536                         free(*k);
 537                         *k = NULL;
 538                 }
 539                 break;
 540         case SSH_ERR_INTERNAL_ERROR:
 541         case SSH_ERR_ALLOC_FAIL:
 542                 fatal_r(r, "load %s \"%s\"", message, path);
 543         case SSH_ERR_SYSTEM_ERROR:
 544                 /* Ignore missing files */
 545                 if (errno == ENOENT)
 546                         break;
 547                 /* FALLTHROUGH */
 548         default:
 549                 error_r(r, "load %s \"%s\"", message, path);
 550                 break;
 551         }
 552 }
 553
 554 /*
 555  * Read per-user configuration file.  Ignore the system wide config
 556  * file if the user specifies a config file on the command line.
 557  */
 558 static void
 559 process_config_files(const char *host_name, struct passwd *pw, int final_pass,
 560     int *want_final_pass)
 561 {
 562         char buf[PATH_MAX];
 563         int r;
 564
 565         if (config != NULL) {
 566                 if (strcasecmp(config, "none") != 0 &&
 567                     !read_config_file(config, pw, host, host_name, &options,
 568                     SSHCONF_USERCONF | (final_pass ? SSHCONF_FINAL : 0),
 569                     want_final_pass))
 570                         fatal("Can't open user config file %.100s: "
 571                             "%.100s", config, strerror(errno));
 572         } else {
 573                 r = snprintf(buf, sizeof buf, "%s/%s", pw->pw_dir,
 574                     _PATH_SSH_USER_CONFFILE);
 575                 if (r > 0 && (size_t)r < sizeof(buf))
 576                         (void)read_config_file(buf, pw, host, host_name,
 577                             &options, SSHCONF_CHECKPERM | SSHCONF_USERCONF |
 578                             (final_pass ? SSHCONF_FINAL : 0), want_final_pass);
 579
 580                 /* Read systemwide configuration file after user config. */
 581                 (void)read_config_file(_PATH_HOST_CONFIG_FILE, pw,
 582                     host, host_name, &options,
 583                     final_pass ? SSHCONF_FINAL : 0, want_final_pass);
 584         }
 585 }
 586
 587 /* Rewrite the port number in an addrinfo list of addresses */
 588 static void
 589 set_addrinfo_port(struct addrinfo *addrs, int port)
 590 {
 591         struct addrinfo *addr;
 592
 593         for (addr = addrs; addr != NULL; addr = addr->ai_next) {
 594                 switch (addr->ai_family) {
 595                 case AF_INET:
 596                         ((struct sockaddr_in *)addr->ai_addr)->
 597                             sin_port = htons(port);
 598                         break;
 599                 case AF_INET6:
 600                         ((struct sockaddr_in6 *)addr->ai_addr)->
 601                             sin6_port = htons(port);
 602                         break;
 603                 }
 604         }
 605 }
 606
 607 static void
 608 ssh_conn_info_free(struct ssh_conn_info *cinfo)
 609 {
 610         if (cinfo == NULL)
 611                 return;
 612         free(cinfo->conn_hash_hex);
 613         free(cinfo->shorthost);
 614         free(cinfo->uidstr);
 615         free(cinfo->keyalias);
 616         free(cinfo->thishost);
 617         free(cinfo->host_arg);
 618         free(cinfo->portstr);
 619         free(cinfo->remhost);
 620         free(cinfo->remuser);
 621         free(cinfo->homedir);
 622         free(cinfo->locuser);
 623         free(cinfo);
 624 }
 625
 626 /*
 627  * Main program for the ssh client.
 628  */
 629 int
 630 main(int ac, char **av)
 631 {
 632         struct ssh *ssh = NULL;
 633         int i, r, opt, exit_status, use_syslog, direct, timeout_ms;
 634         int was_addr, config_test = 0, opt_terminated = 0, want_final_pass = 0;
 635         char *p, *cp, *line, *argv0, *logfile;
 636         char cname[NI_MAXHOST], thishost[NI_MAXHOST];
 637         struct stat st;
 638         struct passwd *pw;
 639         extern int optind, optreset;
 640         extern char *optarg;
 641         struct Forward fwd;
 642         struct addrinfo *addrs = NULL;
 643         size_t n, len;
 644         u_int j;
 645         struct ssh_conn_info *cinfo = NULL;
 646
 647         /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
 648         sanitise_stdfd();
 649
 650         /*
 651          * Discard other fds that are hanging around. These can cause problem
 652          * with backgrounded ssh processes started by ControlPersist.
 653          */
 654         closefrom(STDERR_FILENO + 1);
 655
 656         __progname = ssh_get_progname(av[0]);
 657
 658 #ifndef HAVE_SETPROCTITLE
 659         /* Prepare for later setproctitle emulation */
 660         /* Save argv so it isn't clobbered by setproctitle() emulation */
 661         saved_av = xcalloc(ac + 1, sizeof(*saved_av));
 662         for (i = 0; i < ac; i++)
 663                 saved_av[i] = xstrdup(av[i]);
 664         saved_av[i] = NULL;
 665         compat_init_setproctitle(ac, av);
 666         av = saved_av;
 667 #endif
 668
 669         seed_rng();
 670
 671         /* Get user data. */
 672         pw = getpwuid(getuid());
 673         if (!pw) {
 674                 logit("No user exists for uid %lu", (u_long)getuid());
 675                 exit(255);
 676         }
 677         /* Take a copy of the returned structure. */
 678         pw = pwcopy(pw);
 679
 680         /*
 681          * Set our umask to something reasonable, as some files are created
 682          * with the default umask.  This will make them world-readable but
 683          * writable only by the owner, which is ok for all files for which we
 684          * don't set the modes explicitly.
 685          */
 686         umask(022 | umask(077));
 687
 688         msetlocale();
 689
 690         /*
 691          * Initialize option structure to indicate that no values have been
 692          * set.
 693          */
 694         initialize_options(&options);
 695
 696         /*
 697          * Prepare main ssh transport/connection structures
 698          */
 699         if ((ssh = ssh_alloc_session_state()) == NULL)
 700                 fatal("Couldn't allocate session state");
 701         channel_init_channels(ssh);
 702
 703         /* Parse command-line arguments. */
 704         host = NULL;
 705         use_syslog = 0;
 706         logfile = NULL;
 707         argv0 = av[0];
 708
 709  again:
 710         while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx"
 711             "AB:CD:E:F:GI:J:KL:MNO:PQ:R:S:TVw:W:XYy")) != -1) { /* HUZdhjruz */
 712                 switch (opt) {
 713                 case '1':
 714                         fatal("SSH protocol v.1 is no longer supported");
 715                         break;
 716                 case '2':
 717                         /* Ignored */
 718                         break;
 719                 case '4':
 720                         options.address_family = AF_INET;
 721                         break;
 722                 case '6':
 723                         options.address_family = AF_INET6;
 724                         break;
 725                 case 'n':
 726                         options.stdin_null = 1;
 727                         break;
 728                 case 'f':
 729                         options.fork_after_authentication = 1;
 730                         options.stdin_null = 1;
 731                         break;
 732                 case 'x':
 733                         options.forward_x11 = 0;
 734                         break;
 735                 case 'X':
 736                         options.forward_x11 = 1;
 737                         break;
 738                 case 'y':
 739                         use_syslog = 1;
 740                         break;
 741                 case 'E':
 742                         logfile = optarg;
 743                         break;
 744                 case 'G':
 745                         config_test = 1;
 746                         break;
 747                 case 'Y':
 748                         options.forward_x11 = 1;
 749                         options.forward_x11_trusted = 1;
 750                         break;
 751                 case 'g':
 752                         options.fwd_opts.gateway_ports = 1;
 753                         break;
 754                 case 'O':
 755                         if (options.stdio_forward_host != NULL)
 756                                 fatal("Cannot specify multiplexing "
 757                                     "command with -W");
 758                         else if (muxclient_command != 0)
 759                                 fatal("Multiplexing command already specified");
 760                         if (strcmp(optarg, "check") == 0)
 761                                 muxclient_command = SSHMUX_COMMAND_ALIVE_CHECK;
 762                         else if (strcmp(optarg, "forward") == 0)
 763                                 muxclient_command = SSHMUX_COMMAND_FORWARD;
 764                         else if (strcmp(optarg, "exit") == 0)
 765                                 muxclient_command = SSHMUX_COMMAND_TERMINATE;
 766                         else if (strcmp(optarg, "stop") == 0)
 767                                 muxclient_command = SSHMUX_COMMAND_STOP;
 768                         else if (strcmp(optarg, "cancel") == 0)
 769                                 muxclient_command = SSHMUX_COMMAND_CANCEL_FWD;
 770                         else if (strcmp(optarg, "proxy") == 0)
 771                                 muxclient_command = SSHMUX_COMMAND_PROXY;
 772                         else
 773                                 fatal("Invalid multiplex command.");
 774                         break;
 775                 case 'P':       /* deprecated */
 776                         break;
 777                 case 'Q':
 778                         cp = NULL;
 779                         if (strcmp(optarg, "cipher") == 0 ||
 780                             strcasecmp(optarg, "Ciphers") == 0)
 781                                 cp = cipher_alg_list('\n', 0);
 782                         else if (strcmp(optarg, "cipher-auth") == 0)
 783                                 cp = cipher_alg_list('\n', 1);
 784                         else if (strcmp(optarg, "mac") == 0 ||
 785                             strcasecmp(optarg, "MACs") == 0)
 786                                 cp = mac_alg_list('\n');
 787                         else if (strcmp(optarg, "kex") == 0 ||
 788                             strcasecmp(optarg, "KexAlgorithms") == 0)
 789                                 cp = kex_alg_list('\n');
 790                         else if (strcmp(optarg, "key") == 0)
 791                                 cp = sshkey_alg_list(0, 0, 0, '\n');
 792                         else if (strcmp(optarg, "key-cert") == 0)
 793                                 cp = sshkey_alg_list(1, 0, 0, '\n');
 794                         else if (strcmp(optarg, "key-plain") == 0)
 795                                 cp = sshkey_alg_list(0, 1, 0, '\n');
 796                         else if (strcmp(optarg, "key-sig") == 0 ||
 797                             strcasecmp(optarg, "PubkeyAcceptedKeyTypes") == 0 || /* deprecated name */
 798                             strcasecmp(optarg, "PubkeyAcceptedAlgorithms") == 0 ||
 799                             strcasecmp(optarg, "HostKeyAlgorithms") == 0 ||
 800                             strcasecmp(optarg, "HostbasedKeyTypes") == 0 || /* deprecated name */
 801                             strcasecmp(optarg, "HostbasedAcceptedKeyTypes") == 0 || /* deprecated name */
 802                             strcasecmp(optarg, "HostbasedAcceptedAlgorithms") == 0)
 803                                 cp = sshkey_alg_list(0, 0, 1, '\n');
 804                         else if (strcmp(optarg, "sig") == 0)
 805                                 cp = sshkey_alg_list(0, 1, 1, '\n');
 806                         else if (strcmp(optarg, "protocol-version") == 0)
 807                                 cp = xstrdup("2");
 808                         else if (strcmp(optarg, "compression") == 0) {
 809                                 cp = xstrdup(compression_alg_list(0));
 810                                 len = strlen(cp);
 811                                 for (n = 0; n < len; n++)
 812                                         if (cp[n] == ',')
 813                                                 cp[n] = '\n';
 814                         } else if (strcmp(optarg, "help") == 0) {
 815                                 cp = xstrdup(
 816                                     "cipher\ncipher-auth\ncompression\nkex\n"
 817                                     "key\nkey-cert\nkey-plain\nkey-sig\nmac\n"
 818                                     "protocol-version\nsig");
 819                         }
 820                         if (cp == NULL)
 821                                 fatal("Unsupported query \"%s\"", optarg);
 822                         printf("%s\n", cp);
 823                         free(cp);
 824                         exit(0);
 825                         break;
 826                 case 'a':
 827                         options.forward_agent = 0;
 828                         break;
 829                 case 'A':
 830                         options.forward_agent = 1;
 831                         break;
 832                 case 'k':
 833                         options.gss_deleg_creds = 0;
 834                         break;
 835                 case 'K':
 836                         options.gss_authentication = 1;
 837                         options.gss_deleg_creds = 1;
 838                         break;
 839                 case 'i':
 840                         p = tilde_expand_filename(optarg, getuid());
 841                         if (stat(p, &st) == -1)
 842                                 fprintf(stderr, "Warning: Identity file %s "
 843                                     "not accessible: %s.\n", p,
 844                                     strerror(errno));
 845                         else
 846                                 add_identity_file(&options, NULL, p, 1);
 847                         free(p);
 848                         break;
 849                 case 'I':
 850 #ifdef ENABLE_PKCS11
 851                         free(options.pkcs11_provider);
 852                         options.pkcs11_provider = xstrdup(optarg);
 853 #else
 854                         fprintf(stderr, "no support for PKCS#11.\n");
 855 #endif
 856                         break;
 857                 case 'J':
 858                         if (options.jump_host != NULL) {
 859                                 fatal("Only a single -J option is permitted "
 860                                     "(use commas to separate multiple "
 861                                     "jump hops)");
 862                         }
 863                         if (options.proxy_command != NULL)
 864                                 fatal("Cannot specify -J with ProxyCommand");
 865                         if (parse_jump(optarg, &options, 1) == -1)
 866                                 fatal("Invalid -J argument");
 867                         options.proxy_command = xstrdup("none");
 868                         break;
 869                 case 't':
 870                         if (options.request_tty == REQUEST_TTY_YES)
 871                                 options.request_tty = REQUEST_TTY_FORCE;
 872                         else
 873                                 options.request_tty = REQUEST_TTY_YES;
 874                         break;
 875                 case 'v':
 876                         if (debug_flag == 0) {
 877                                 debug_flag = 1;
 878                                 options.log_level = SYSLOG_LEVEL_DEBUG1;
 879                         } else {
 880                                 if (options.log_level < SYSLOG_LEVEL_DEBUG3) {
 881                                         debug_flag++;
 882                                         options.log_level++;
 883                                 }
 884                         }
 885                         break;
 886                 case 'V':
 887                         fprintf(stderr, "%s, %s\n",
 888                             SSH_RELEASE, SSH_OPENSSL_VERSION);
 889                         exit(0);
 890                         break;
 891                 case 'w':
 892                         if (options.tun_open == -1)
 893                                 options.tun_open = SSH_TUNMODE_DEFAULT;
 894                         options.tun_local = a2tun(optarg, &options.tun_remote);
 895                         if (options.tun_local == SSH_TUNID_ERR) {
 896                                 fprintf(stderr,
 897                                     "Bad tun device '%s'\n", optarg);
 898                                 exit(255);
 899                         }
 900                         break;
 901                 case 'W':
 902                         if (options.stdio_forward_host != NULL)
 903                                 fatal("stdio forward already specified");
 904                         if (muxclient_command != 0)
 905                                 fatal("Cannot specify stdio forward with -O");
 906                         if (parse_forward(&fwd, optarg, 1, 0)) {
 907                                 options.stdio_forward_host = fwd.listen_host;
 908                                 options.stdio_forward_port = fwd.listen_port;
 909                                 free(fwd.connect_host);
 910                         } else {
 911                                 fprintf(stderr,
 912                                     "Bad stdio forwarding specification '%s'\n",
 913                                     optarg);
 914                                 exit(255);
 915                         }
 916                         options.request_tty = REQUEST_TTY_NO;
 917                         options.session_type = SESSION_TYPE_NONE;
 918                         break;
 919                 case 'q':
 920                         options.log_level = SYSLOG_LEVEL_QUIET;
 921                         break;
 922                 case 'e':
 923                         if (optarg[0] == '^' && optarg[2] == 0 &&
 924                             (u_char) optarg[1] >= 64 &&
 925                             (u_char) optarg[1] < 128)
 926                                 options.escape_char = (u_char) optarg[1] & 31;
 927                         else if (strlen(optarg) == 1)
 928                                 options.escape_char = (u_char) optarg[0];
 929                         else if (strcmp(optarg, "none") == 0)
 930                                 options.escape_char = SSH_ESCAPECHAR_NONE;
 931                         else {
 932                                 fprintf(stderr, "Bad escape character '%s'.\n",
 933                                     optarg);
 934                                 exit(255);
 935                         }
 936                         break;
 937                 case 'c':
 938                         if (!ciphers_valid(*optarg == '+' || *optarg == '^' ?
 939                             optarg + 1 : optarg)) {
 940                                 fprintf(stderr, "Unknown cipher type '%s'\n",
 941                                     optarg);
 942                                 exit(255);
 943                         }
 944                         free(options.ciphers);
 945                         options.ciphers = xstrdup(optarg);
 946                         break;
 947                 case 'm':
 948                         if (mac_valid(optarg)) {
 949                                 free(options.macs);
 950                                 options.macs = xstrdup(optarg);
 951                         } else {
 952                                 fprintf(stderr, "Unknown mac type '%s'\n",
 953                                     optarg);
 954                                 exit(255);
 955                         }
 956                         break;
 957                 case 'M':
 958                         if (options.control_master == SSHCTL_MASTER_YES)
 959                                 options.control_master = SSHCTL_MASTER_ASK;
 960                         else
 961                                 options.control_master = SSHCTL_MASTER_YES;
 962                         break;
 963                 case 'p':
 964                         if (options.port == -1) {
 965                                 options.port = a2port(optarg);
 966                                 if (options.port <= 0) {
 967                                         fprintf(stderr, "Bad port '%s'\n",
 968                                             optarg);
 969                                         exit(255);
 970                                 }
 971                         }
 972                         break;
 973                 case 'l':
 974                         if (options.user == NULL)
 975                                 options.user = optarg;
 976                         break;
 977
 978                 case 'L':
 979                         if (parse_forward(&fwd, optarg, 0, 0))
 980                                 add_local_forward(&options, &fwd);
 981                         else {
 982                                 fprintf(stderr,
 983                                     "Bad local forwarding specification '%s'\n",
 984                                     optarg);
 985                                 exit(255);
 986                         }
 987                         break;
 988
 989                 case 'R':
 990                         if (parse_forward(&fwd, optarg, 0, 1) ||
 991                             parse_forward(&fwd, optarg, 1, 1)) {
 992                                 add_remote_forward(&options, &fwd);
 993                         } else {
 994                                 fprintf(stderr,
 995                                     "Bad remote forwarding specification "
 996                                     "'%s'\n", optarg);
 997                                 exit(255);
 998                         }
 999                         break;
1000
1001                 case 'D':
1002                         if (parse_forward(&fwd, optarg, 1, 0)) {
1003                                 add_local_forward(&options, &fwd);
1004                         } else {
1005                                 fprintf(stderr,
1006                                     "Bad dynamic forwarding specification "
1007                                     "'%s'\n", optarg);
1008                                 exit(255);
1009                         }
1010                         break;
1011
1012                 case 'C':
1013 #ifdef WITH_ZLIB
1014                         options.compression = 1;
1015 #else
1016                         error("Compression not supported, disabling.");
1017 #endif
1018                         break;
1019                 case 'N':
1020                         if (options.session_type != -1 &&
1021                             options.session_type != SESSION_TYPE_NONE)
1022                                 fatal("Cannot specify -N with -s/SessionType");
1023                         options.session_type = SESSION_TYPE_NONE;
1024                         options.request_tty = REQUEST_TTY_NO;
1025                         break;
1026                 case 'T':
1027                         options.request_tty = REQUEST_TTY_NO;
1028                         break;
1029                 case 'o':
1030                         line = xstrdup(optarg);
1031                         if (process_config_line(&options, pw,
1032                             host ? host : "", host ? host : "", line,
1033                             "command-line", 0, NULL, SSHCONF_USERCONF) != 0)
1034                                 exit(255);
1035                         free(line);
1036                         break;
1037                 case 's':
1038                         if (options.session_type != -1 &&
1039                             options.session_type != SESSION_TYPE_SUBSYSTEM)
1040                                 fatal("Cannot specify -s with -N/SessionType");
1041                         options.session_type = SESSION_TYPE_SUBSYSTEM;
1042                         break;
1043                 case 'S':
1044                         free(options.control_path);
1045                         options.control_path = xstrdup(optarg);
1046                         break;
1047                 case 'b':
1048                         options.bind_address = optarg;
1049                         break;
1050                 case 'B':
1051                         options.bind_interface = optarg;
1052                         break;
1053                 case 'F':
1054                         config = optarg;
1055                         break;
1056                 default:
1057                         usage();
1058                 }
1059         }
1060
1061         if (optind > 1 && strcmp(av[optind - 1], "--") == 0)
1062                 opt_terminated = 1;
1063
1064         ac -= optind;
1065         av += optind;
1066
1067         if (ac > 0 && !host) {
1068                 int tport;
1069                 char *tuser;
1070                 switch (parse_ssh_uri(*av, &tuser, &host, &tport)) {
1071                 case -1:
1072                         usage();
1073                         break;
1074                 case 0:
1075                         if (options.user == NULL) {
1076                                 options.user = tuser;
1077                                 tuser = NULL;
1078                         }
1079                         free(tuser);
1080                         if (options.port == -1 && tport != -1)
1081                                 options.port = tport;
1082                         break;
1083                 default:
1084                         p = xstrdup(*av);
1085                         cp = strrchr(p, '@');
1086                         if (cp != NULL) {
1087                                 if (cp == p)
1088                                         usage();
1089                                 if (options.user == NULL) {
1090                                         options.user = p;
1091                                         p = NULL;
1092                                 }
1093                                 *cp++ = '\0';
1094                                 host = xstrdup(cp);
1095                                 free(p);
1096                         } else
1097                                 host = p;
1098                         break;
1099                 }
1100                 if (ac > 1 && !opt_terminated) {
1101                         optind = optreset = 1;
1102                         goto again;
1103                 }
1104                 ac--, av++;
1105         }
1106
1107         /* Check that we got a host name. */
1108         if (!host)
1109                 usage();
1110
1111         options.host_arg = xstrdup(host);
1112
1113         /* Initialize the command to execute on remote host. */
1114         if ((command = sshbuf_new()) == NULL)
1115                 fatal("sshbuf_new failed");
1116
1117         /*
1118          * Save the command to execute on the remote host in a buffer. There
1119          * is no limit on the length of the command, except by the maximum
1120          * packet size.  Also sets the tty flag if there is no command.
1121          */
1122         if (!ac) {
1123                 /* No command specified - execute shell on a tty. */
1124                 if (options.session_type == SESSION_TYPE_SUBSYSTEM) {
1125                         fprintf(stderr,
1126                             "You must specify a subsystem to invoke.\n");
1127                         usage();
1128                 }
1129         } else {
1130                 /* A command has been specified.  Store it into the buffer. */
1131                 for (i = 0; i < ac; i++) {
1132                         if ((r = sshbuf_putf(command, "%s%s",
1133                             i ? " " : "", av[i])) != 0)
1134                                 fatal_fr(r, "buffer error");
1135                 }
1136         }
1137
1138         ssh_signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */
1139
1140         /*
1141          * Initialize "log" output.  Since we are the client all output
1142          * goes to stderr unless otherwise specified by -y or -E.
1143          */
1144         if (use_syslog && logfile != NULL)
1145                 fatal("Can't specify both -y and -E");
1146         if (logfile != NULL)
1147                 log_redirect_stderr_to(logfile);
1148         log_init(argv0,
1149             options.log_level == SYSLOG_LEVEL_NOT_SET ?
1150             SYSLOG_LEVEL_INFO : options.log_level,
1151             options.log_facility == SYSLOG_FACILITY_NOT_SET ?
1152             SYSLOG_FACILITY_USER : options.log_facility,
1153             !use_syslog);
1154
1155         if (debug_flag)
1156                 logit("%s, %s", SSH_RELEASE, SSH_OPENSSL_VERSION);
1157
1158         /* Parse the configuration files */
1159         process_config_files(options.host_arg, pw, 0, &want_final_pass);
1160         if (want_final_pass)
1161                 debug("configuration requests final Match pass");
1162
1163         /* Hostname canonicalisation needs a few options filled. */
1164         fill_default_options_for_canonicalization(&options);
1165
1166         /* If the user has replaced the hostname then take it into use now */
1167         if (options.hostname != NULL) {
1168                 /* NB. Please keep in sync with readconf.c:match_cfg_line() */
1169                 cp = percent_expand(options.hostname,
1170                     "h", host, (char *)NULL);
1171                 free(host);
1172                 host = cp;
1173                 free(options.hostname);
1174                 options.hostname = xstrdup(host);
1175         }
1176
1177         /* Don't lowercase addresses, they will be explicitly canonicalised */
1178         if ((was_addr = is_addr(host)) == 0)
1179                 lowercase(host);
1180
1181         /*
1182          * Try to canonicalize if requested by configuration or the
1183          * hostname is an address.
1184          */
1185         if (options.canonicalize_hostname != SSH_CANONICALISE_NO || was_addr)
1186                 addrs = resolve_canonicalize(&host, options.port);
1187
1188         /*
1189          * If CanonicalizePermittedCNAMEs have been specified but
1190          * other canonicalization did not happen (by not being requested
1191          * or by failing with fallback) then the hostname may still be changed
1192          * as a result of CNAME following.
1193          *
1194          * Try to resolve the bare hostname name using the system resolver's
1195          * usual search rules and then apply the CNAME follow rules.
1196          *
1197          * Skip the lookup if a ProxyCommand is being used unless the user
1198          * has specifically requested canonicalisation for this case via
1199          * CanonicalizeHostname=always
1200          */
1201         direct = option_clear_or_none(options.proxy_command) &&
1202             options.jump_host == NULL;
1203         if (addrs == NULL && config_has_permitted_cnames(&options) && (direct ||
1204             options.canonicalize_hostname == SSH_CANONICALISE_ALWAYS)) {
1205                 if ((addrs = resolve_host(host, options.port,
1206                     direct, cname, sizeof(cname))) == NULL) {
1207                         /* Don't fatal proxied host names not in the DNS */
1208                         if (direct)
1209                                 cleanup_exit(255); /* logged in resolve_host */
1210                 } else
1211                         check_follow_cname(direct, &host, cname);
1212         }
1213
1214         /*
1215          * If canonicalisation is enabled then re-parse the configuration
1216          * files as new stanzas may match.
1217          */
1218         if (options.canonicalize_hostname != 0 && !want_final_pass) {
1219                 debug("hostname canonicalisation enabled, "
1220                     "will re-parse configuration");
1221                 want_final_pass = 1;
1222         }
1223
1224         if (want_final_pass) {
1225                 debug("re-parsing configuration");
1226                 free(options.hostname);
1227                 options.hostname = xstrdup(host);
1228                 process_config_files(options.host_arg, pw, 1, NULL);
1229                 /*
1230                  * Address resolution happens early with canonicalisation
1231                  * enabled and the port number may have changed since, so
1232                  * reset it in address list
1233                  */
1234                 if (addrs != NULL && options.port > 0)
1235                         set_addrinfo_port(addrs, options.port);
1236         }
1237
1238         /* Fill configuration defaults. */
1239         if (fill_default_options(&options) != 0)
1240                 cleanup_exit(255);
1241
1242         if (options.user == NULL)
1243                 options.user = xstrdup(pw->pw_name);
1244
1245         /*
1246          * If ProxyJump option specified, then construct a ProxyCommand now.
1247          */
1248         if (options.jump_host != NULL) {
1249                 char port_s[8];
1250                 const char *jumpuser = options.jump_user, *sshbin = argv0;
1251                 int port = options.port, jumpport = options.jump_port;
1252
1253                 if (port <= 0)
1254                         port = default_ssh_port();
1255                 if (jumpport <= 0)
1256                         jumpport = default_ssh_port();
1257                 if (jumpuser == NULL)
1258                         jumpuser = options.user;
1259                 if (strcmp(options.jump_host, host) == 0 && port == jumpport &&
1260                     strcmp(options.user, jumpuser) == 0)
1261                         fatal("jumphost loop via %s", options.jump_host);
1262
1263                 /*
1264                  * Try to use SSH indicated by argv[0], but fall back to
1265                  * "ssh" if it appears unavailable.
1266                  */
1267                 if (strchr(argv0, '/') != NULL && access(argv0, X_OK) != 0)
1268                         sshbin = "ssh";
1269
1270                 /* Consistency check */
1271                 if (options.proxy_command != NULL)
1272                         fatal("inconsistent options: ProxyCommand+ProxyJump");
1273                 /* Never use FD passing for ProxyJump */
1274                 options.proxy_use_fdpass = 0;
1275                 snprintf(port_s, sizeof(port_s), "%d", options.jump_port);
1276                 xasprintf(&options.proxy_command,
1277                     "%s%s%s%s%s%s%s%s%s%s%.*s -W '[%%h]:%%p' %s",
1278                     sshbin,
1279                     /* Optional "-l user" argument if jump_user set */
1280                     options.jump_user == NULL ? "" : " -l ",
1281                     options.jump_user == NULL ? "" : options.jump_user,
1282                     /* Optional "-p port" argument if jump_port set */
1283                     options.jump_port <= 0 ? "" : " -p ",
1284                     options.jump_port <= 0 ? "" : port_s,
1285                     /* Optional additional jump hosts ",..." */
1286                     options.jump_extra == NULL ? "" : " -J ",
1287                     options.jump_extra == NULL ? "" : options.jump_extra,
1288                     /* Optional "-F" argument if -F specified */
1289                     config == NULL ? "" : " -F ",
1290                     config == NULL ? "" : config,
1291                     /* Optional "-v" arguments if -v set */
1292                     debug_flag ? " -" : "",
1293                     debug_flag, "vvv",
1294                     /* Mandatory hostname */
1295                     options.jump_host);
1296                 debug("Setting implicit ProxyCommand from ProxyJump: %s",
1297                     options.proxy_command);
1298         }
1299
1300         if (options.port == 0)
1301                 options.port = default_ssh_port();
1302         channel_set_af(ssh, options.address_family);
1303
1304         /* Tidy and check options */
1305         if (options.host_key_alias != NULL)
1306                 lowercase(options.host_key_alias);
1307         if (options.proxy_command != NULL &&
1308             strcmp(options.proxy_command, "-") == 0 &&
1309             options.proxy_use_fdpass)
1310                 fatal("ProxyCommand=- and ProxyUseFDPass are incompatible");
1311         if (options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK) {
1312                 if (options.control_persist && options.control_path != NULL) {
1313                         debug("UpdateHostKeys=ask is incompatible with "
1314                             "ControlPersist; disabling");
1315                         options.update_hostkeys = 0;
1316                 } else if (sshbuf_len(command) != 0 ||
1317                     options.remote_command != NULL ||
1318                     options.request_tty == REQUEST_TTY_NO) {
1319                         debug("UpdateHostKeys=ask is incompatible with "
1320                             "remote command execution; disabling");
1321                         options.update_hostkeys = 0;
1322                 } else if (options.log_level < SYSLOG_LEVEL_INFO) {
1323                         /* no point logging anything; user won't see it */
1324                         options.update_hostkeys = 0;
1325                 }
1326         }
1327         if (options.connection_attempts <= 0)
1328                 fatal("Invalid number of ConnectionAttempts");
1329
1330         if (sshbuf_len(command) != 0 && options.remote_command != NULL)
1331                 fatal("Cannot execute command-line and remote command.");
1332
1333         /* Cannot fork to background if no command. */
1334         if (options.fork_after_authentication && sshbuf_len(command) == 0 &&
1335             options.remote_command == NULL &&
1336             options.session_type != SESSION_TYPE_NONE)
1337                 fatal("Cannot fork into background without a command "
1338                     "to execute.");
1339
1340         /* reinit */
1341         log_init(argv0, options.log_level, options.log_facility, !use_syslog);
1342         for (j = 0; j < options.num_log_verbose; j++) {
1343                 if (strcasecmp(options.log_verbose[j], "none") == 0)
1344                         break;
1345                 log_verbose_add(options.log_verbose[j]);
1346         }
1347
1348         if (options.request_tty == REQUEST_TTY_YES ||
1349             options.request_tty == REQUEST_TTY_FORCE)
1350                 tty_flag = 1;
1351
1352         /* Allocate a tty by default if no command specified. */
1353         if (sshbuf_len(command) == 0 && options.remote_command == NULL)
1354                 tty_flag = options.request_tty != REQUEST_TTY_NO;
1355
1356         /* Force no tty */
1357         if (options.request_tty == REQUEST_TTY_NO ||
1358             (muxclient_command && muxclient_command != SSHMUX_COMMAND_PROXY) ||
1359             options.session_type == SESSION_TYPE_NONE)
1360                 tty_flag = 0;
1361         /* Do not allocate a tty if stdin is not a tty. */
1362         if ((!isatty(fileno(stdin)) || options.stdin_null) &&
1363             options.request_tty != REQUEST_TTY_FORCE) {
1364                 if (tty_flag)
1365                         logit("Pseudo-terminal will not be allocated because "
1366                             "stdin is not a terminal.");
1367                 tty_flag = 0;
1368         }
1369
1370         /* Set up strings used to percent_expand() arguments */
1371         cinfo = xcalloc(1, sizeof(*cinfo));
1372         if (gethostname(thishost, sizeof(thishost)) == -1)
1373                 fatal("gethostname: %s", strerror(errno));
1374         cinfo->thishost = xstrdup(thishost);
1375         thishost[strcspn(thishost, ".")] = '\0';
1376         cinfo->shorthost = xstrdup(thishost);
1377         xasprintf(&cinfo->portstr, "%d", options.port);
1378         xasprintf(&cinfo->uidstr, "%llu",
1379             (unsigned long long)pw->pw_uid);
1380         cinfo->keyalias = xstrdup(options.host_key_alias ?
1381             options.host_key_alias : options.host_arg);
1382         cinfo->conn_hash_hex = ssh_connection_hash(cinfo->thishost, host,
1383             cinfo->portstr, options.user);
1384         cinfo->host_arg = xstrdup(options.host_arg);
1385         cinfo->remhost = xstrdup(host);
1386         cinfo->remuser = xstrdup(options.user);
1387         cinfo->homedir = xstrdup(pw->pw_dir);
1388         cinfo->locuser = xstrdup(pw->pw_name);
1389
1390         /* Find canonic host name. */
1391         if (strchr(host, '.') == NULL) {
1392                 struct addrinfo hints;
1393                 struct addrinfo *ai = NULL;
1394                 int errgai;
1395
1396                 memset(&hints, 0, sizeof(hints));
1397                 hints.ai_family = options.address_family;
1398                 hints.ai_flags = AI_CANONNAME;
1399                 hints.ai_socktype = SOCK_STREAM;
1400                 errgai = getaddrinfo(host, NULL, &hints, &ai);
1401                 if (errgai == 0) {
1402                         if (ai->ai_canonname != NULL) {
1403                                 free(host);
1404                                 host = xstrdup(ai->ai_canonname);
1405                         }
1406                         freeaddrinfo(ai);
1407                 }
1408         }
1409
1410         /*
1411          * Expand tokens in arguments. NB. LocalCommand is expanded later,
1412          * after port-forwarding is set up, so it may pick up any local
1413          * tunnel interface name allocated.
1414          */
1415         if (options.remote_command != NULL) {
1416                 debug3("expanding RemoteCommand: %s", options.remote_command);
1417                 cp = options.remote_command;
1418                 options.remote_command = default_client_percent_expand(cp,
1419                     cinfo);
1420                 debug3("expanded RemoteCommand: %s", options.remote_command);
1421                 free(cp);
1422                 if ((r = sshbuf_put(command, options.remote_command,
1423                     strlen(options.remote_command))) != 0)
1424                         fatal_fr(r, "buffer error");
1425         }
1426
1427         if (options.control_path != NULL) {
1428                 cp = tilde_expand_filename(options.control_path, getuid());
1429                 free(options.control_path);
1430                 options.control_path = default_client_percent_dollar_expand(cp,
1431                     cinfo);
1432                 free(cp);
1433         }
1434
1435         if (options.identity_agent != NULL) {
1436                 p = tilde_expand_filename(options.identity_agent, getuid());
1437                 cp = default_client_percent_dollar_expand(p, cinfo);
1438                 free(p);
1439                 free(options.identity_agent);
1440                 options.identity_agent = cp;
1441         }
1442
1443         if (options.forward_agent_sock_path != NULL) {
1444                 p = tilde_expand_filename(options.forward_agent_sock_path,
1445                     getuid());
1446                 cp = default_client_percent_dollar_expand(p, cinfo);
1447                 free(p);
1448                 free(options.forward_agent_sock_path);
1449                 options.forward_agent_sock_path = cp;
1450                 if (stat(options.forward_agent_sock_path, &st) != 0) {
1451                         error("Cannot forward agent socket path \"%s\": %s",
1452                             options.forward_agent_sock_path, strerror(errno));
1453                         if (options.exit_on_forward_failure)
1454                                 cleanup_exit(255);
1455                 }
1456         }
1457
1458         if (options.num_system_hostfiles > 0 &&
1459             strcasecmp(options.system_hostfiles[0], "none") == 0) {
1460                 if (options.num_system_hostfiles > 1)
1461                         fatal("Invalid GlobalKnownHostsFiles: \"none\" "
1462                             "appears with other entries");
1463                 free(options.system_hostfiles[0]);
1464                 options.system_hostfiles[0] = NULL;
1465                 options.num_system_hostfiles = 0;
1466         }
1467
1468         if (options.num_user_hostfiles > 0 &&
1469             strcasecmp(options.user_hostfiles[0], "none") == 0) {
1470                 if (options.num_user_hostfiles > 1)
1471                         fatal("Invalid UserKnownHostsFiles: \"none\" "
1472                             "appears with other entries");
1473                 free(options.user_hostfiles[0]);
1474                 options.user_hostfiles[0] = NULL;
1475                 options.num_user_hostfiles = 0;
1476         }
1477         for (j = 0; j < options.num_user_hostfiles; j++) {
1478                 if (options.user_hostfiles[j] == NULL)
1479                         continue;
1480                 cp = tilde_expand_filename(options.user_hostfiles[j], getuid());
1481                 p = default_client_percent_dollar_expand(cp, cinfo);
1482                 if (strcmp(options.user_hostfiles[j], p) != 0)
1483                         debug3("expanded UserKnownHostsFile '%s' -> "
1484                             "'%s'", options.user_hostfiles[j], p);
1485                 free(options.user_hostfiles[j]);
1486                 free(cp);
1487                 options.user_hostfiles[j] = p;
1488         }
1489
1490         for (i = 0; i < options.num_local_forwards; i++) {
1491                 if (options.local_forwards[i].listen_path != NULL) {
1492                         cp = options.local_forwards[i].listen_path;
1493                         p = options.local_forwards[i].listen_path =
1494                             default_client_percent_expand(cp, cinfo);
1495                         if (strcmp(cp, p) != 0)
1496                                 debug3("expanded LocalForward listen path "
1497                                     "'%s' -> '%s'", cp, p);
1498                         free(cp);
1499                 }
1500                 if (options.local_forwards[i].connect_path != NULL) {
1501                         cp = options.local_forwards[i].connect_path;
1502                         p = options.local_forwards[i].connect_path =
1503                             default_client_percent_expand(cp, cinfo);
1504                         if (strcmp(cp, p) != 0)
1505                                 debug3("expanded LocalForward connect path "
1506                                     "'%s' -> '%s'", cp, p);
1507                         free(cp);
1508                 }
1509         }
1510
1511         for (i = 0; i < options.num_remote_forwards; i++) {
1512                 if (options.remote_forwards[i].listen_path != NULL) {
1513                         cp = options.remote_forwards[i].listen_path;
1514                         p = options.remote_forwards[i].listen_path =
1515                             default_client_percent_expand(cp, cinfo);
1516                         if (strcmp(cp, p) != 0)
1517                                 debug3("expanded RemoteForward listen path "
1518                                     "'%s' -> '%s'", cp, p);
1519                         free(cp);
1520                 }
1521                 if (options.remote_forwards[i].connect_path != NULL) {
1522                         cp = options.remote_forwards[i].connect_path;
1523                         p = options.remote_forwards[i].connect_path =
1524                             default_client_percent_expand(cp, cinfo);
1525                         if (strcmp(cp, p) != 0)
1526                                 debug3("expanded RemoteForward connect path "
1527                                     "'%s' -> '%s'", cp, p);
1528                         free(cp);
1529                 }
1530         }
1531
1532         if (config_test) {
1533                 dump_client_config(&options, host);
1534                 exit(0);
1535         }
1536
1537         /* Expand SecurityKeyProvider if it refers to an environment variable */
1538         if (options.sk_provider != NULL && *options.sk_provider == '$' &&
1539             strlen(options.sk_provider) > 1) {
1540                 if ((cp = getenv(options.sk_provider + 1)) == NULL) {
1541                         debug("Authenticator provider %s did not resolve; "
1542                             "disabling", options.sk_provider);
1543                         free(options.sk_provider);
1544                         options.sk_provider = NULL;
1545                 } else {
1546                         debug2("resolved SecurityKeyProvider %s => %s",
1547                             options.sk_provider, cp);
1548                         free(options.sk_provider);
1549                         options.sk_provider = xstrdup(cp);
1550                 }
1551         }
1552
1553         if (muxclient_command != 0 && options.control_path == NULL)
1554                 fatal("No ControlPath specified for \"-O\" command");
1555         if (options.control_path != NULL) {
1556                 int sock;
1557                 if ((sock = muxclient(options.control_path)) >= 0) {
1558                         ssh_packet_set_connection(ssh, sock, sock);
1559                         ssh_packet_set_mux(ssh);
1560                         goto skip_connect;
1561                 }
1562         }
1563
1564         /*
1565          * If hostname canonicalisation was not enabled, then we may not
1566          * have yet resolved the hostname. Do so now.
1567          */
1568         if (addrs == NULL && options.proxy_command == NULL) {
1569                 debug2("resolving \"%s\" port %d", host, options.port);
1570                 if ((addrs = resolve_host(host, options.port, 1,
1571                     cname, sizeof(cname))) == NULL)
1572                         cleanup_exit(255); /* resolve_host logs the error */
1573         }
1574
1575         if (options.connection_timeout >= INT_MAX/1000)
1576                 timeout_ms = INT_MAX;
1577         else
1578                 timeout_ms = options.connection_timeout * 1000;
1579
1580         /* Open a connection to the remote host. */
1581         if (ssh_connect(ssh, host, options.host_arg, addrs, &hostaddr,
1582             options.port, options.connection_attempts,
1583             &timeout_ms, options.tcp_keep_alive) != 0)
1584                 exit(255);
1585
1586         if (addrs != NULL)
1587                 freeaddrinfo(addrs);
1588
1589         ssh_packet_set_timeout(ssh, options.server_alive_interval,
1590             options.server_alive_count_max);
1591
1592         if (timeout_ms > 0)
1593                 debug3("timeout: %d ms remain after connect", timeout_ms);
1594
1595         /*
1596          * If we successfully made the connection and we have hostbased auth
1597          * enabled, load the public keys so we can later use the ssh-keysign
1598          * helper to sign challenges.
1599          */
1600         sensitive_data.nkeys = 0;
1601         sensitive_data.keys = NULL;
1602         if (options.hostbased_authentication) {
1603                 int loaded = 0;
1604
1605                 sensitive_data.nkeys = 10;
1606                 sensitive_data.keys = xcalloc(sensitive_data.nkeys,
1607                     sizeof(*sensitive_data.keys));
1608
1609                 /* XXX check errors? */
1610 #define L_PUBKEY(p,o) do { \
1611         if ((o) >= sensitive_data.nkeys) \
1612                 fatal_f("pubkey out of array bounds"); \
1613         check_load(sshkey_load_public(p, &(sensitive_data.keys[o]), NULL), \
1614             &(sensitive_data.keys[o]), p, "pubkey"); \
1615         if (sensitive_data.keys[o] != NULL) { \
1616                 debug2("hostbased key %d: %s key from \"%s\"", o, \
1617                     sshkey_ssh_name(sensitive_data.keys[o]), p); \
1618                 loaded++; \
1619         } \
1620 } while (0)
1621 #define L_CERT(p,o) do { \
1622         if ((o) >= sensitive_data.nkeys) \
1623                 fatal_f("cert out of array bounds"); \
1624         check_load(sshkey_load_cert(p, &(sensitive_data.keys[o])), \
1625             &(sensitive_data.keys[o]), p, "cert"); \
1626         if (sensitive_data.keys[o] != NULL) { \
1627                 debug2("hostbased key %d: %s cert from \"%s\"", o, \
1628                     sshkey_ssh_name(sensitive_data.keys[o]), p); \
1629                 loaded++; \
1630         } \
1631 } while (0)
1632
1633                 if (options.hostbased_authentication == 1) {
1634                         L_CERT(_PATH_HOST_ECDSA_KEY_FILE, 0);
1635                         L_CERT(_PATH_HOST_ED25519_KEY_FILE, 1);
1636                         L_CERT(_PATH_HOST_RSA_KEY_FILE, 2);
1637                         L_CERT(_PATH_HOST_DSA_KEY_FILE, 3);
1638                         L_PUBKEY(_PATH_HOST_ECDSA_KEY_FILE, 4);
1639                         L_PUBKEY(_PATH_HOST_ED25519_KEY_FILE, 5);
1640                         L_PUBKEY(_PATH_HOST_RSA_KEY_FILE, 6);
1641                         L_PUBKEY(_PATH_HOST_DSA_KEY_FILE, 7);
1642                         L_CERT(_PATH_HOST_XMSS_KEY_FILE, 8);
1643                         L_PUBKEY(_PATH_HOST_XMSS_KEY_FILE, 9);
1644                         if (loaded == 0)
1645                                 debug("HostbasedAuthentication enabled but no "
1646                                    "local public host keys could be loaded.");
1647                 }
1648         }
1649
1650         /* load options.identity_files */
1651         load_public_identity_files(cinfo);
1652
1653         /* optionally set the SSH_AUTHSOCKET_ENV_NAME variable */
1654         if (options.identity_agent &&
1655             strcmp(options.identity_agent, SSH_AUTHSOCKET_ENV_NAME) != 0) {
1656                 if (strcmp(options.identity_agent, "none") == 0) {
1657                         unsetenv(SSH_AUTHSOCKET_ENV_NAME);
1658                 } else {
1659                         cp = options.identity_agent;
1660                         /* legacy (limited) format */
1661                         if (cp[0] == '$' && cp[1] != '{') {
1662                                 if (!valid_env_name(cp + 1)) {
1663                                         fatal("Invalid IdentityAgent "
1664                                             "environment variable name %s", cp);
1665                                 }
1666                                 if ((p = getenv(cp + 1)) == NULL)
1667                                         unsetenv(SSH_AUTHSOCKET_ENV_NAME);
1668                                 else
1669                                         setenv(SSH_AUTHSOCKET_ENV_NAME, p, 1);
1670                         } else {
1671                                 /* identity_agent specifies a path directly */
1672                                 setenv(SSH_AUTHSOCKET_ENV_NAME, cp, 1);
1673                         }
1674                 }
1675         }
1676
1677         if (options.forward_agent && options.forward_agent_sock_path != NULL) {
1678                 cp = options.forward_agent_sock_path;
1679                 if (cp[0] == '$') {
1680                         if (!valid_env_name(cp + 1)) {
1681                                 fatal("Invalid ForwardAgent environment variable name %s", cp);
1682                         }
1683                         if ((p = getenv(cp + 1)) != NULL)
1684                                 forward_agent_sock_path = xstrdup(p);
1685                         else
1686                                 options.forward_agent = 0;
1687                         free(cp);
1688                 } else {
1689                         forward_agent_sock_path = cp;
1690                 }
1691         }
1692
1693         /* Expand ~ in known host file names. */
1694         tilde_expand_paths(options.system_hostfiles,
1695             options.num_system_hostfiles);
1696         tilde_expand_paths(options.user_hostfiles, options.num_user_hostfiles);
1697
1698         ssh_signal(SIGCHLD, main_sigchld_handler);
1699
1700         /* Log into the remote system.  Never returns if the login fails. */
1701         ssh_login(ssh, &sensitive_data, host, (struct sockaddr *)&hostaddr,
1702             options.port, pw, timeout_ms, cinfo);
1703
1704         /* We no longer need the private host keys.  Clear them now. */
1705         if (sensitive_data.nkeys != 0) {
1706                 for (i = 0; i < sensitive_data.nkeys; i++) {
1707                         if (sensitive_data.keys[i] != NULL) {
1708                                 /* Destroys contents safely */
1709                                 debug3("clear hostkey %d", i);
1710                                 sshkey_free(sensitive_data.keys[i]);
1711                                 sensitive_data.keys[i] = NULL;
1712                         }
1713                 }
1714                 free(sensitive_data.keys);
1715         }
1716         for (i = 0; i < options.num_identity_files; i++) {
1717                 free(options.identity_files[i]);
1718                 options.identity_files[i] = NULL;
1719                 if (options.identity_keys[i]) {
1720                         sshkey_free(options.identity_keys[i]);
1721                         options.identity_keys[i] = NULL;
1722                 }
1723         }
1724         for (i = 0; i < options.num_certificate_files; i++) {
1725                 free(options.certificate_files[i]);
1726                 options.certificate_files[i] = NULL;
1727         }
1728
1729 #ifdef ENABLE_PKCS11
1730         (void)pkcs11_del_provider(options.pkcs11_provider);
1731 #endif
1732
1733  skip_connect:
1734         exit_status = ssh_session2(ssh, cinfo);
1735         ssh_conn_info_free(cinfo);
1736         ssh_packet_close(ssh);
1737
1738         if (options.control_path != NULL && muxserver_sock != -1)
1739                 unlink(options.control_path);
1740
1741         /* Kill ProxyCommand if it is running. */
1742         ssh_kill_proxy_command();
1743
1744         return exit_status;
1745 }
1746
1747 static void
1748 control_persist_detach(void)
1749 {
1750         pid_t pid;
1751
1752         debug_f("backgrounding master process");
1753
1754         /*
1755          * master (current process) into the background, and make the
1756          * foreground process a client of the backgrounded master.
1757          */
1758         switch ((pid = fork())) {
1759         case -1:
1760                 fatal_f("fork: %s", strerror(errno));
1761         case 0:
1762                 /* Child: master process continues mainloop */
1763                 break;
1764         default:
1765                 /* Parent: set up mux client to connect to backgrounded master */
1766                 debug2_f("background process is %ld", (long)pid);
1767                 options.stdin_null = ostdin_null_flag;
1768                 options.request_tty = orequest_tty;
1769                 tty_flag = otty_flag;
1770                 options.session_type = osession_type;
1771                 close(muxserver_sock);
1772                 muxserver_sock = -1;
1773                 options.control_master = SSHCTL_MASTER_NO;
1774                 muxclient(options.control_path);
1775                 /* muxclient() doesn't return on success. */
1776                 fatal("Failed to connect to new control master");
1777         }
1778         if (stdfd_devnull(1, 1, !(log_is_on_stderr() && debug_flag)) == -1)
1779                 error_f("stdfd_devnull failed");
1780         daemon(1, 1);
1781         setproctitle("%s [mux]", options.control_path);
1782 }
1783
1784 /* Do fork() after authentication. Used by "ssh -f" */
1785 static void
1786 fork_postauth(void)
1787 {
1788         if (need_controlpersist_detach)
1789                 control_persist_detach();
1790         debug("forking to background");
1791         options.fork_after_authentication = 0;
1792         if (daemon(1, 1) == -1)
1793                 fatal("daemon() failed: %.200s", strerror(errno));
1794         if (stdfd_devnull(1, 1, !(log_is_on_stderr() && debug_flag)) == -1)
1795                 error_f("stdfd_devnull failed");
1796 }
1797
1798 static void
1799 forwarding_success(void)
1800 {
1801         if (forward_confirms_pending == -1)
1802                 return;
1803         if (--forward_confirms_pending == 0) {
1804                 debug_f("all expected forwarding replies received");
1805                 if (options.fork_after_authentication)
1806                         fork_postauth();
1807         } else {
1808                 debug2_f("%d expected forwarding replies remaining",
1809                     forward_confirms_pending);
1810         }
1811 }
1812
1813 /* Callback for remote forward global requests */
1814 static void
1815 ssh_confirm_remote_forward(struct ssh *ssh, int type, u_int32_t seq, void *ctxt)
1816 {
1817         struct Forward *rfwd = (struct Forward *)ctxt;
1818         u_int port;
1819         int r;
1820
1821         /* XXX verbose() on failure? */
1822         debug("remote forward %s for: listen %s%s%d, connect %s:%d",
1823             type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure",
1824             rfwd->listen_path ? rfwd->listen_path :
1825             rfwd->listen_host ? rfwd->listen_host : "",
1826             (rfwd->listen_path || rfwd->listen_host) ? ":" : "",
1827             rfwd->listen_port, rfwd->connect_path ? rfwd->connect_path :
1828             rfwd->connect_host, rfwd->connect_port);
1829         if (rfwd->listen_path == NULL && rfwd->listen_port == 0) {
1830                 if (type == SSH2_MSG_REQUEST_SUCCESS) {
1831                         if ((r = sshpkt_get_u32(ssh, &port)) != 0)
1832                                 fatal_fr(r, "parse packet");
1833                         if (port > 65535) {
1834                                 error("Invalid allocated port %u for remote "
1835                                     "forward to %s:%d", port,
1836                                     rfwd->connect_host, rfwd->connect_port);
1837                                 /* Ensure failure processing runs below */
1838                                 type = SSH2_MSG_REQUEST_FAILURE;
1839                                 channel_update_permission(ssh,
1840                                     rfwd->handle, -1);
1841                         } else {
1842                                 rfwd->allocated_port = (int)port;
1843                                 logit("Allocated port %u for remote "
1844                                     "forward to %s:%d",
1845                                     rfwd->allocated_port, rfwd->connect_path ?
1846                                     rfwd->connect_path : rfwd->connect_host,
1847                                     rfwd->connect_port);
1848                                 channel_update_permission(ssh,
1849                                     rfwd->handle, rfwd->allocated_port);
1850                         }
1851                 } else {
1852                         channel_update_permission(ssh, rfwd->handle, -1);
1853                 }
1854         }
1855
1856         if (type == SSH2_MSG_REQUEST_FAILURE) {
1857                 if (options.exit_on_forward_failure) {
1858                         if (rfwd->listen_path != NULL)
1859                                 fatal("Error: remote port forwarding failed "
1860                                     "for listen path %s", rfwd->listen_path);
1861                         else
1862                                 fatal("Error: remote port forwarding failed "
1863                                     "for listen port %d", rfwd->listen_port);
1864                 } else {
1865                         if (rfwd->listen_path != NULL)
1866                                 logit("Warning: remote port forwarding failed "
1867                                     "for listen path %s", rfwd->listen_path);
1868                         else
1869                                 logit("Warning: remote port forwarding failed "
1870                                     "for listen port %d", rfwd->listen_port);
1871                 }
1872         }
1873         forwarding_success();
1874 }
1875
1876 static void
1877 client_cleanup_stdio_fwd(struct ssh *ssh, int id, int force, void *arg)
1878 {
1879         debug("stdio forwarding: done");
1880         cleanup_exit(0);
1881 }
1882
1883 static void
1884 ssh_stdio_confirm(struct ssh *ssh, int id, int success, void *arg)
1885 {
1886         if (!success)
1887                 fatal("stdio forwarding failed");
1888 }
1889
1890 static void
1891 ssh_tun_confirm(struct ssh *ssh, int id, int success, void *arg)
1892 {
1893         if (!success) {
1894                 error("Tunnel forwarding failed");
1895                 if (options.exit_on_forward_failure)
1896                         cleanup_exit(255);
1897         }
1898
1899         debug_f("tunnel forward established, id=%d", id);
1900         forwarding_success();
1901 }
1902
1903 static void
1904 ssh_init_stdio_forwarding(struct ssh *ssh)
1905 {
1906         Channel *c;
1907         int in, out;
1908
1909         if (options.stdio_forward_host == NULL)
1910                 return;
1911
1912         debug3_f("%s:%d", options.stdio_forward_host,
1913             options.stdio_forward_port);
1914
1915         if ((in = dup(STDIN_FILENO)) == -1 ||
1916             (out = dup(STDOUT_FILENO)) == -1)
1917                 fatal_f("dup() in/out failed");
1918         if ((c = channel_connect_stdio_fwd(ssh, options.stdio_forward_host,
1919             options.stdio_forward_port, in, out,
1920             CHANNEL_NONBLOCK_STDIO)) == NULL)
1921                 fatal_f("channel_connect_stdio_fwd failed");
1922         channel_register_cleanup(ssh, c->self, client_cleanup_stdio_fwd, 0);
1923         channel_register_open_confirm(ssh, c->self, ssh_stdio_confirm, NULL);
1924 }
1925
1926 static void
1927 ssh_init_forward_permissions(struct ssh *ssh, const char *what, char **opens,
1928     u_int num_opens)
1929 {
1930         u_int i;
1931         int port;
1932         char *addr, *arg, *oarg;
1933         int where = FORWARD_LOCAL;
1934
1935         channel_clear_permission(ssh, FORWARD_ADM, where);
1936         if (num_opens == 0)
1937                 return; /* permit any */
1938
1939         /* handle keywords: "any" / "none" */
1940         if (num_opens == 1 && strcmp(opens[0], "any") == 0)
1941                 return;
1942         if (num_opens == 1 && strcmp(opens[0], "none") == 0) {
1943                 channel_disable_admin(ssh, where);
1944                 return;
1945         }
1946         /* Otherwise treat it as a list of permitted host:port */
1947         for (i = 0; i < num_opens; i++) {
1948                 oarg = arg = xstrdup(opens[i]);
1949                 addr = hpdelim(&arg);
1950                 if (addr == NULL)
1951                         fatal_f("missing host in %s", what);
1952                 addr = cleanhostname(addr);
1953                 if (arg == NULL || ((port = permitopen_port(arg)) < 0))
1954                         fatal_f("bad port number in %s", what);
1955                 /* Send it to channels layer */
1956                 channel_add_permission(ssh, FORWARD_ADM,
1957                     where, addr, port);
1958                 free(oarg);
1959         }
1960 }
1961
1962 static void
1963 ssh_init_forwarding(struct ssh *ssh, char **ifname)
1964 {
1965         int success = 0;
1966         int i;
1967
1968         ssh_init_forward_permissions(ssh, "permitremoteopen",
1969             options.permitted_remote_opens,
1970             options.num_permitted_remote_opens);
1971
1972         if (options.exit_on_forward_failure)
1973                 forward_confirms_pending = 0; /* track pending requests */
1974         /* Initiate local TCP/IP port forwardings. */
1975         for (i = 0; i < options.num_local_forwards; i++) {
1976                 debug("Local connections to %.200s:%d forwarded to remote "
1977                     "address %.200s:%d",
1978                     (options.local_forwards[i].listen_path != NULL) ?
1979                     options.local_forwards[i].listen_path :
1980                     (options.local_forwards[i].listen_host == NULL) ?
1981                     (options.fwd_opts.gateway_ports ? "*" : "LOCALHOST") :
1982                     options.local_forwards[i].listen_host,
1983                     options.local_forwards[i].listen_port,
1984                     (options.local_forwards[i].connect_path != NULL) ?
1985                     options.local_forwards[i].connect_path :
1986                     options.local_forwards[i].connect_host,
1987                     options.local_forwards[i].connect_port);
1988                 success += channel_setup_local_fwd_listener(ssh,
1989                     &options.local_forwards[i], &options.fwd_opts);
1990         }
1991         if (i > 0 && success != i && options.exit_on_forward_failure)
1992                 fatal("Could not request local forwarding.");
1993         if (i > 0 && success == 0)
1994                 error("Could not request local forwarding.");
1995
1996         /* Initiate remote TCP/IP port forwardings. */
1997         for (i = 0; i < options.num_remote_forwards; i++) {
1998                 debug("Remote connections from %.200s:%d forwarded to "
1999                     "local address %.200s:%d",
2000                     (options.remote_forwards[i].listen_path != NULL) ?
2001                     options.remote_forwards[i].listen_path :
2002                     (options.remote_forwards[i].listen_host == NULL) ?
2003                     "LOCALHOST" : options.remote_forwards[i].listen_host,
2004                     options.remote_forwards[i].listen_port,
2005                     (options.remote_forwards[i].connect_path != NULL) ?
2006                     options.remote_forwards[i].connect_path :
2007                     options.remote_forwards[i].connect_host,
2008                     options.remote_forwards[i].connect_port);
2009                 if ((options.remote_forwards[i].handle =
2010                     channel_request_remote_forwarding(ssh,
2011                     &options.remote_forwards[i])) >= 0) {
2012                         client_register_global_confirm(
2013                             ssh_confirm_remote_forward,
2014                             &options.remote_forwards[i]);
2015                         forward_confirms_pending++;
2016                 } else if (options.exit_on_forward_failure)
2017                         fatal("Could not request remote forwarding.");
2018                 else
2019                         logit("Warning: Could not request remote forwarding.");
2020         }
2021
2022         /* Initiate tunnel forwarding. */
2023         if (options.tun_open != SSH_TUNMODE_NO) {
2024                 if ((*ifname = client_request_tun_fwd(ssh,
2025                     options.tun_open, options.tun_local,
2026                     options.tun_remote, ssh_tun_confirm, NULL)) != NULL)
2027                         forward_confirms_pending++;
2028                 else if (options.exit_on_forward_failure)
2029                         fatal("Could not request tunnel forwarding.");
2030                 else
2031                         error("Could not request tunnel forwarding.");
2032         }
2033         if (forward_confirms_pending > 0) {
2034                 debug_f("expecting replies for %d forwards",
2035                     forward_confirms_pending);
2036         }
2037 }
2038
2039 static void
2040 check_agent_present(void)
2041 {
2042         int r;
2043
2044         if (options.forward_agent) {
2045                 /* Clear agent forwarding if we don't have an agent. */
2046                 if ((r = ssh_get_authentication_socket(NULL)) != 0) {
2047                         options.forward_agent = 0;
2048                         if (r != SSH_ERR_AGENT_NOT_PRESENT)
2049                                 debug_r(r, "ssh_get_authentication_socket");
2050                 }
2051         }
2052 }
2053
2054 static void
2055 ssh_session2_setup(struct ssh *ssh, int id, int success, void *arg)
2056 {
2057         extern char **environ;
2058         const char *display, *term;
2059         int r, interactive = tty_flag;
2060         char *proto = NULL, *data = NULL;
2061
2062         if (!success)
2063                 return; /* No need for error message, channels code sends one */
2064
2065         display = getenv("DISPLAY");
2066         if (display == NULL && options.forward_x11)
2067                 debug("X11 forwarding requested but DISPLAY not set");
2068         if (options.forward_x11 && client_x11_get_proto(ssh, display,
2069             options.xauth_location, options.forward_x11_trusted,
2070             options.forward_x11_timeout, &proto, &data) == 0) {
2071                 /* Request forwarding with authentication spoofing. */
2072                 debug("Requesting X11 forwarding with authentication "
2073                     "spoofing.");
2074                 x11_request_forwarding_with_spoofing(ssh, id, display, proto,
2075                     data, 1);
2076                 client_expect_confirm(ssh, id, "X11 forwarding", CONFIRM_WARN);
2077                 /* XXX exit_on_forward_failure */
2078                 interactive = 1;
2079         }
2080
2081         check_agent_present();
2082         if (options.forward_agent) {
2083                 debug("Requesting authentication agent forwarding.");
2084                 channel_request_start(ssh, id, "auth-agent-req@openssh.com", 0);
2085                 if ((r = sshpkt_send(ssh)) != 0)
2086                         fatal_fr(r, "send packet");
2087         }
2088
2089         /* Tell the packet module whether this is an interactive session. */
2090         ssh_packet_set_interactive(ssh, interactive,
2091             options.ip_qos_interactive, options.ip_qos_bulk);
2092
2093         if ((term = lookup_env_in_list("TERM", options.setenv,
2094             options.num_setenv)) == NULL || *term == '\0')
2095                 term = getenv("TERM");
2096         client_session2_setup(ssh, id, tty_flag,
2097             options.session_type == SESSION_TYPE_SUBSYSTEM, term,
2098             NULL, fileno(stdin), command, environ);
2099 }
2100
2101 /* open new channel for a session */
2102 static int
2103 ssh_session2_open(struct ssh *ssh)
2104 {
2105         Channel *c;
2106         int window, packetmax, in, out, err;
2107
2108         if (options.stdin_null) {
2109                 in = open(_PATH_DEVNULL, O_RDONLY);
2110         } else {
2111                 in = dup(STDIN_FILENO);
2112         }
2113         out = dup(STDOUT_FILENO);
2114         err = dup(STDERR_FILENO);
2115
2116         if (in == -1 || out == -1 || err == -1)
2117                 fatal("dup() in/out/err failed");
2118
2119         window = CHAN_SES_WINDOW_DEFAULT;
2120         packetmax = CHAN_SES_PACKET_DEFAULT;
2121         if (tty_flag) {
2122                 window >>= 1;
2123                 packetmax >>= 1;
2124         }
2125         c = channel_new(ssh,
2126             "session", SSH_CHANNEL_OPENING, in, out, err,
2127             window, packetmax, CHAN_EXTENDED_WRITE,
2128             "client-session", CHANNEL_NONBLOCK_STDIO);
2129
2130         debug3_f("channel_new: %d", c->self);
2131
2132         channel_send_open(ssh, c->self);
2133         if (options.session_type != SESSION_TYPE_NONE)
2134                 channel_register_open_confirm(ssh, c->self,
2135                     ssh_session2_setup, NULL);
2136
2137         return c->self;
2138 }
2139
2140 static int
2141 ssh_session2(struct ssh *ssh, const struct ssh_conn_info *cinfo)
2142 {
2143         int r, id = -1;
2144         char *cp, *tun_fwd_ifname = NULL;
2145
2146         /* XXX should be pre-session */
2147         if (!options.control_persist)
2148                 ssh_init_stdio_forwarding(ssh);
2149
2150         ssh_init_forwarding(ssh, &tun_fwd_ifname);
2151
2152         if (options.local_command != NULL) {
2153                 debug3("expanding LocalCommand: %s", options.local_command);
2154                 cp = options.local_command;
2155                 options.local_command = percent_expand(cp,
2156                     DEFAULT_CLIENT_PERCENT_EXPAND_ARGS(cinfo),
2157                     "T", tun_fwd_ifname == NULL ? "NONE" : tun_fwd_ifname,
2158                     (char *)NULL);
2159                 debug3("expanded LocalCommand: %s", options.local_command);
2160                 free(cp);
2161         }
2162
2163         /* Start listening for multiplex clients */
2164         if (!ssh_packet_get_mux(ssh))
2165                 muxserver_listen(ssh);
2166
2167         /*
2168          * If we are in control persist mode and have a working mux listen
2169          * socket, then prepare to background ourselves and have a foreground
2170          * client attach as a control client.
2171          * NB. we must save copies of the flags that we override for
2172          * the backgrounding, since we defer attachment of the client until
2173          * after the connection is fully established (in particular,
2174          * async rfwd replies have been received for ExitOnForwardFailure).
2175          */
2176         if (options.control_persist && muxserver_sock != -1) {
2177                 ostdin_null_flag = options.stdin_null;
2178                 osession_type = options.session_type;
2179                 orequest_tty = options.request_tty;
2180                 otty_flag = tty_flag;
2181                 options.stdin_null = 1;
2182                 options.session_type = SESSION_TYPE_NONE;
2183                 tty_flag = 0;
2184                 if (!options.fork_after_authentication &&
2185                     (osession_type != SESSION_TYPE_NONE ||
2186                     options.stdio_forward_host != NULL))
2187                         need_controlpersist_detach = 1;
2188                 options.fork_after_authentication = 1;
2189         }
2190         /*
2191          * ControlPersist mux listen socket setup failed, attempt the
2192          * stdio forward setup that we skipped earlier.
2193          */
2194         if (options.control_persist && muxserver_sock == -1)
2195                 ssh_init_stdio_forwarding(ssh);
2196
2197         if (options.session_type != SESSION_TYPE_NONE)
2198                 id = ssh_session2_open(ssh);
2199         else {
2200                 ssh_packet_set_interactive(ssh,
2201                     options.control_master == SSHCTL_MASTER_NO,
2202                     options.ip_qos_interactive, options.ip_qos_bulk);
2203         }
2204
2205         /* If we don't expect to open a new session, then disallow it */
2206         if (options.control_master == SSHCTL_MASTER_NO &&
2207             (ssh->compat & SSH_NEW_OPENSSH)) {
2208                 debug("Requesting no-more-sessions@openssh.com");
2209                 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 ||
2210                     (r = sshpkt_put_cstring(ssh,
2211                     "no-more-sessions@openssh.com")) != 0 ||
2212                     (r = sshpkt_put_u8(ssh, 0)) != 0 ||
2213                     (r = sshpkt_send(ssh)) != 0)
2214                         fatal_fr(r, "send packet");
2215         }
2216
2217         /* Execute a local command */
2218         if (options.local_command != NULL &&
2219             options.permit_local_command)
2220                 ssh_local_cmd(options.local_command);
2221
2222         /*
2223          * stdout is now owned by the session channel; clobber it here
2224          * so future channel closes are propagated to the local fd.
2225          * NB. this can only happen after LocalCommand has completed,
2226          * as it may want to write to stdout.
2227          */
2228         if (!need_controlpersist_detach && stdfd_devnull(0, 1, 0) == -1)
2229                 error_f("stdfd_devnull failed");
2230
2231         /*
2232          * If requested and we are not interested in replies to remote
2233          * forwarding requests, then let ssh continue in the background.
2234          */
2235         if (options.fork_after_authentication) {
2236                 if (options.exit_on_forward_failure &&
2237                     options.num_remote_forwards > 0) {
2238                         debug("deferring postauth fork until remote forward "
2239                             "confirmation received");
2240                 } else
2241                         fork_postauth();
2242         }
2243
2244         return client_loop(ssh, tty_flag, tty_flag ?
2245             options.escape_char : SSH_ESCAPECHAR_NONE, id);
2246 }
2247
2248 /* Loads all IdentityFile and CertificateFile keys */
2249 static void
2250 load_public_identity_files(const struct ssh_conn_info *cinfo)
2251 {
2252         char *filename, *cp;
2253         struct sshkey *public;
2254         int i;
2255         u_int n_ids, n_certs;
2256         char *identity_files[SSH_MAX_IDENTITY_FILES];
2257         struct sshkey *identity_keys[SSH_MAX_IDENTITY_FILES];
2258         int identity_file_userprovided[SSH_MAX_IDENTITY_FILES];
2259         char *certificate_files[SSH_MAX_CERTIFICATE_FILES];
2260         struct sshkey *certificates[SSH_MAX_CERTIFICATE_FILES];
2261         int certificate_file_userprovided[SSH_MAX_CERTIFICATE_FILES];
2262 #ifdef ENABLE_PKCS11
2263         struct sshkey **keys = NULL;
2264         char **comments = NULL;
2265         int nkeys;
2266 #endif /* PKCS11 */
2267
2268         n_ids = n_certs = 0;
2269         memset(identity_files, 0, sizeof(identity_files));
2270         memset(identity_keys, 0, sizeof(identity_keys));
2271         memset(identity_file_userprovided, 0,
2272             sizeof(identity_file_userprovided));
2273         memset(certificate_files, 0, sizeof(certificate_files));
2274         memset(certificates, 0, sizeof(certificates));
2275         memset(certificate_file_userprovided, 0,
2276             sizeof(certificate_file_userprovided));
2277
2278 #ifdef ENABLE_PKCS11
2279         if (options.pkcs11_provider != NULL &&
2280             options.num_identity_files < SSH_MAX_IDENTITY_FILES &&
2281             (pkcs11_init(!options.batch_mode) == 0) &&
2282             (nkeys = pkcs11_add_provider(options.pkcs11_provider, NULL,
2283             &keys, &comments)) > 0) {
2284                 for (i = 0; i < nkeys; i++) {
2285                         if (n_ids >= SSH_MAX_IDENTITY_FILES) {
2286                                 sshkey_free(keys[i]);
2287                                 free(comments[i]);
2288                                 continue;
2289                         }
2290                         identity_keys[n_ids] = keys[i];
2291                         identity_files[n_ids] = comments[i]; /* transferred */
2292                         n_ids++;
2293                 }
2294                 free(keys);
2295                 free(comments);
2296         }
2297 #endif /* ENABLE_PKCS11 */
2298         for (i = 0; i < options.num_identity_files; i++) {
2299                 if (n_ids >= SSH_MAX_IDENTITY_FILES ||
2300                     strcasecmp(options.identity_files[i], "none") == 0) {
2301                         free(options.identity_files[i]);
2302                         options.identity_files[i] = NULL;
2303                         continue;
2304                 }
2305                 cp = tilde_expand_filename(options.identity_files[i], getuid());
2306                 filename = default_client_percent_dollar_expand(cp, cinfo);
2307                 free(cp);
2308                 check_load(sshkey_load_public(filename, &public, NULL),
2309                     &public, filename, "pubkey");
2310                 debug("identity file %s type %d", filename,
2311                     public ? public->type : -1);
2312                 free(options.identity_files[i]);
2313                 identity_files[n_ids] = filename;
2314                 identity_keys[n_ids] = public;
2315                 identity_file_userprovided[n_ids] =
2316                     options.identity_file_userprovided[i];
2317                 if (++n_ids >= SSH_MAX_IDENTITY_FILES)
2318                         continue;
2319
2320                 /*
2321                  * If no certificates have been explicitly listed then try
2322                  * to add the default certificate variant too.
2323                  */
2324                 if (options.num_certificate_files != 0)
2325                         continue;
2326                 xasprintf(&cp, "%s-cert", filename);
2327                 check_load(sshkey_load_public(cp, &public, NULL),
2328                     &public, filename, "pubkey");
2329                 debug("identity file %s type %d", cp,
2330                     public ? public->type : -1);
2331                 if (public == NULL) {
2332                         free(cp);
2333                         continue;
2334                 }
2335                 if (!sshkey_is_cert(public)) {
2336                         debug_f("key %s type %s is not a certificate",
2337                             cp, sshkey_type(public));
2338                         sshkey_free(public);
2339                         free(cp);
2340                         continue;
2341                 }
2342                 /* NB. leave filename pointing to private key */
2343                 identity_files[n_ids] = xstrdup(filename);
2344                 identity_keys[n_ids] = public;
2345                 identity_file_userprovided[n_ids] =
2346                     options.identity_file_userprovided[i];
2347                 n_ids++;
2348         }
2349
2350         if (options.num_certificate_files > SSH_MAX_CERTIFICATE_FILES)
2351                 fatal_f("too many certificates");
2352         for (i = 0; i < options.num_certificate_files; i++) {
2353                 cp = tilde_expand_filename(options.certificate_files[i],
2354                     getuid());
2355                 filename = default_client_percent_dollar_expand(cp, cinfo);
2356                 free(cp);
2357
2358                 check_load(sshkey_load_public(filename, &public, NULL),
2359                     &public, filename, "certificate");
2360                 debug("certificate file %s type %d", filename,
2361                     public ? public->type : -1);
2362                 free(options.certificate_files[i]);
2363                 options.certificate_files[i] = NULL;
2364                 if (public == NULL) {
2365                         free(filename);
2366                         continue;
2367                 }
2368                 if (!sshkey_is_cert(public)) {
2369                         debug_f("key %s type %s is not a certificate",
2370                             filename, sshkey_type(public));
2371                         sshkey_free(public);
2372                         free(filename);
2373                         continue;
2374                 }
2375                 certificate_files[n_certs] = filename;
2376                 certificates[n_certs] = public;
2377                 certificate_file_userprovided[n_certs] =
2378                     options.certificate_file_userprovided[i];
2379                 ++n_certs;
2380         }
2381
2382         options.num_identity_files = n_ids;
2383         memcpy(options.identity_files, identity_files, sizeof(identity_files));
2384         memcpy(options.identity_keys, identity_keys, sizeof(identity_keys));
2385         memcpy(options.identity_file_userprovided,
2386             identity_file_userprovided, sizeof(identity_file_userprovided));
2387
2388         options.num_certificate_files = n_certs;
2389         memcpy(options.certificate_files,
2390             certificate_files, sizeof(certificate_files));
2391         memcpy(options.certificates, certificates, sizeof(certificates));
2392         memcpy(options.certificate_file_userprovided,
2393             certificate_file_userprovided,
2394             sizeof(certificate_file_userprovided));
2395 }
2396
2397 static void
2398 main_sigchld_handler(int sig)
2399 {
2400         int save_errno = errno;
2401         pid_t pid;
2402         int status;
2403
2404         while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
2405             (pid == -1 && errno == EINTR))
2406                 ;
2407         errno = save_errno;
2408 }