crypto/openssh/ssh.c

   1 /* $OpenBSD: ssh.c,v 1.594 2023/09/03 23:59:32 djm Exp $ */
   2 /*
   3  * Author: Tatu Ylonen <ylo@cs.hut.fi>
   4  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
   5  *                    All rights reserved
   6  * Ssh client program.  This program can be used to log into a remote machine.
   7  * The software supports strong authentication, encryption, and forwarding
   8  * of X11, TCP/IP, and authentication connections.
   9  *
  10  * As far as I am concerned, the code I have written for this software
  11  * can be used freely for any purpose.  Any derived versions of this
  12  * software must be clearly marked as such, and if the derived work is
  13  * incompatible with the protocol description in the RFC file, it must be
  14  * called by a name other than "ssh" or "Secure Shell".
  15  *
  16  * Copyright (c) 1999 Niels Provos.  All rights reserved.
  17  * Copyright (c) 2000, 2001, 2002, 2003 Markus Friedl.  All rights reserved.
  18  *
  19  * Modified to work with 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 static int need_controlpersist_detach = 0;
 134
 135 /* Copies of flags for ControlPersist foreground mux-client */
 136 static int ostdin_null_flag, osession_type, otty_flag, orequest_tty;
 137 static int ofork_after_authentication;
 138
 139 /*
 140  * General data structure for command line options and options configurable
 141  * in configuration files.  See readconf.h.
 142  */
 143 Options options;
 144
 145 /* optional user configfile */
 146 char *config = NULL;
 147
 148 /*
 149  * Name of the host we are connecting to.  This is the name given on the
 150  * command line, or the Hostname specified for the user-supplied name in a
 151  * configuration file.
 152  */
 153 char *host;
 154
 155 /*
 156  * A config can specify a path to forward, overriding SSH_AUTH_SOCK. If this is
 157  * not NULL, forward the socket at this path instead.
 158  */
 159 char *forward_agent_sock_path = NULL;
 160
 161 /* socket address the host resolves to */
 162 struct sockaddr_storage hostaddr;
 163
 164 /* Private host keys. */
 165 Sensitive sensitive_data;
 166
 167 /* command to be executed */
 168 struct sshbuf *command;
 169
 170 /* # of replies received for global requests */
 171 static int forward_confirms_pending = -1;
 172
 173 /* mux.c */
 174 extern int muxserver_sock;
 175 extern u_int muxclient_command;
 176
 177 /* Prints a help message to the user.  This function never returns. */
 178
 179 static void
 180 usage(void)
 181 {
 182         fprintf(stderr,
 183 "usage: ssh [-46AaCfGgKkMNnqsTtVvXxYy] [-B bind_interface] [-b bind_address]\n"
 184 "           [-c cipher_spec] [-D [bind_address:]port] [-E log_file]\n"
 185 "           [-e escape_char] [-F configfile] [-I pkcs11] [-i identity_file]\n"
 186 "           [-J destination] [-L address] [-l login_name] [-m mac_spec]\n"
 187 "           [-O ctl_cmd] [-o option] [-P tag] [-p port] [-Q query_option]\n"
 188 "           [-R address] [-S ctl_path] [-W host:port] [-w local_tun[:remote_tun]]\n"
 189 "           destination [command [argument ...]]\n"
 190         );
 191         exit(255);
 192 }
 193
 194 static int ssh_session2(struct ssh *, const struct ssh_conn_info *);
 195 static void load_public_identity_files(const struct ssh_conn_info *);
 196 static void main_sigchld_handler(int);
 197
 198 /* ~/ expand a list of paths. NB. assumes path[n] is heap-allocated. */
 199 static void
 200 tilde_expand_paths(char **paths, u_int num_paths)
 201 {
 202         u_int i;
 203         char *cp;
 204
 205         for (i = 0; i < num_paths; i++) {
 206                 cp = tilde_expand_filename(paths[i], getuid());
 207                 free(paths[i]);
 208                 paths[i] = cp;
 209         }
 210 }
 211
 212 /*
 213  * Expands the set of percent_expand options used by the majority of keywords
 214  * in the client that support percent expansion.
 215  * Caller must free returned string.
 216  */
 217 static char *
 218 default_client_percent_expand(const char *str,
 219     const struct ssh_conn_info *cinfo)
 220 {
 221         return percent_expand(str,
 222             DEFAULT_CLIENT_PERCENT_EXPAND_ARGS(cinfo),
 223             (char *)NULL);
 224 }
 225
 226 /*
 227  * Expands the set of percent_expand options used by the majority of keywords
 228  * AND perform environment variable substitution.
 229  * Caller must free returned string.
 230  */
 231 static char *
 232 default_client_percent_dollar_expand(const char *str,
 233     const struct ssh_conn_info *cinfo)
 234 {
 235         char *ret;
 236
 237         ret = percent_dollar_expand(str,
 238             DEFAULT_CLIENT_PERCENT_EXPAND_ARGS(cinfo),
 239             (char *)NULL);
 240         if (ret == NULL)
 241                 fatal("invalid environment variable expansion");
 242         return ret;
 243 }
 244
 245 /*
 246  * Attempt to resolve a host name / port to a set of addresses and
 247  * optionally return any CNAMEs encountered along the way.
 248  * Returns NULL on failure.
 249  * NB. this function must operate with a options having undefined members.
 250  */
 251 static struct addrinfo *
 252 resolve_host(const char *name, int port, int logerr, char *cname, size_t clen)
 253 {
 254         char strport[NI_MAXSERV];
 255         const char *errstr = NULL;
 256         struct addrinfo hints, *res;
 257         int gaierr;
 258         LogLevel loglevel = SYSLOG_LEVEL_DEBUG1;
 259
 260         if (port <= 0)
 261                 port = default_ssh_port();
 262         if (cname != NULL)
 263                 *cname = '\0';
 264         debug3_f("lookup %s:%d", name, port);
 265
 266         snprintf(strport, sizeof strport, "%d", port);
 267         memset(&hints, 0, sizeof(hints));
 268         hints.ai_family = options.address_family == -1 ?
 269             AF_UNSPEC : options.address_family;
 270         hints.ai_socktype = SOCK_STREAM;
 271         if (cname != NULL)
 272                 hints.ai_flags = AI_CANONNAME;
 273         if ((gaierr = getaddrinfo(name, strport, &hints, &res)) != 0) {
 274                 if (logerr || (gaierr != EAI_NONAME && gaierr != EAI_NODATA))
 275                         loglevel = SYSLOG_LEVEL_ERROR;
 276                 do_log2(loglevel, "%s: Could not resolve hostname %.100s: %s",
 277                     __progname, name, ssh_gai_strerror(gaierr));
 278                 return NULL;
 279         }
 280         if (cname != NULL && res->ai_canonname != NULL) {
 281                 if (!valid_domain(res->ai_canonname, 0, &errstr)) {
 282                         error("ignoring bad CNAME \"%s\" for host \"%s\": %s",
 283                             res->ai_canonname, name, errstr);
 284                 } else if (strlcpy(cname, res->ai_canonname, clen) >= clen) {
 285                         error_f("host \"%s\" cname \"%s\" too long (max %lu)",
 286                             name,  res->ai_canonname, (u_long)clen);
 287                         if (clen > 0)
 288                                 *cname = '\0';
 289                 }
 290         }
 291         return res;
 292 }
 293
 294 /* Returns non-zero if name can only be an address and not a hostname */
 295 static int
 296 is_addr_fast(const char *name)
 297 {
 298         return (strchr(name, '%') != NULL || strchr(name, ':') != NULL ||
 299             strspn(name, "0123456789.") == strlen(name));
 300 }
 301
 302 /* Returns non-zero if name represents a valid, single address */
 303 static int
 304 is_addr(const char *name)
 305 {
 306         char strport[NI_MAXSERV];
 307         struct addrinfo hints, *res;
 308
 309         if (is_addr_fast(name))
 310                 return 1;
 311
 312         snprintf(strport, sizeof strport, "%u", default_ssh_port());
 313         memset(&hints, 0, sizeof(hints));
 314         hints.ai_family = options.address_family == -1 ?
 315             AF_UNSPEC : options.address_family;
 316         hints.ai_socktype = SOCK_STREAM;
 317         hints.ai_flags = AI_NUMERICHOST|AI_NUMERICSERV;
 318         if (getaddrinfo(name, strport, &hints, &res) != 0)
 319                 return 0;
 320         if (res == NULL || res->ai_next != NULL) {
 321                 freeaddrinfo(res);
 322                 return 0;
 323         }
 324         freeaddrinfo(res);
 325         return 1;
 326 }
 327
 328 /*
 329  * Attempt to resolve a numeric host address / port to a single address.
 330  * Returns a canonical address string.
 331  * Returns NULL on failure.
 332  * NB. this function must operate with a options having undefined members.
 333  */
 334 static struct addrinfo *
 335 resolve_addr(const char *name, int port, char *caddr, size_t clen)
 336 {
 337         char addr[NI_MAXHOST], strport[NI_MAXSERV];
 338         struct addrinfo hints, *res;
 339         int gaierr;
 340
 341         if (port <= 0)
 342                 port = default_ssh_port();
 343         snprintf(strport, sizeof strport, "%u", port);
 344         memset(&hints, 0, sizeof(hints));
 345         hints.ai_family = options.address_family == -1 ?
 346             AF_UNSPEC : options.address_family;
 347         hints.ai_socktype = SOCK_STREAM;
 348         hints.ai_flags = AI_NUMERICHOST|AI_NUMERICSERV;
 349         if ((gaierr = getaddrinfo(name, strport, &hints, &res)) != 0) {
 350                 debug2_f("could not resolve name %.100s as address: %s",
 351                     name, ssh_gai_strerror(gaierr));
 352                 return NULL;
 353         }
 354         if (res == NULL) {
 355                 debug_f("getaddrinfo %.100s returned no addresses", name);
 356                 return NULL;
 357         }
 358         if (res->ai_next != NULL) {
 359                 debug_f("getaddrinfo %.100s returned multiple addresses", name);
 360                 goto fail;
 361         }
 362         if ((gaierr = getnameinfo(res->ai_addr, res->ai_addrlen,
 363             addr, sizeof(addr), NULL, 0, NI_NUMERICHOST)) != 0) {
 364                 debug_f("Could not format address for name %.100s: %s",
 365                     name, ssh_gai_strerror(gaierr));
 366                 goto fail;
 367         }
 368         if (strlcpy(caddr, addr, clen) >= clen) {
 369                 error_f("host \"%s\" addr \"%s\" too long (max %lu)",
 370                     name,  addr, (u_long)clen);
 371                 if (clen > 0)
 372                         *caddr = '\0';
 373  fail:
 374                 freeaddrinfo(res);
 375                 return NULL;
 376         }
 377         return res;
 378 }
 379
 380 /*
 381  * Check whether the cname is a permitted replacement for the hostname
 382  * and perform the replacement if it is.
 383  * NB. this function must operate with a options having undefined members.
 384  */
 385 static int
 386 check_follow_cname(int direct, char **namep, const char *cname)
 387 {
 388         int i;
 389         struct allowed_cname *rule;
 390
 391         if (*cname == '\0' || !config_has_permitted_cnames(&options) ||
 392             strcmp(*namep, cname) == 0)
 393                 return 0;
 394         if (options.canonicalize_hostname == SSH_CANONICALISE_NO)
 395                 return 0;
 396         /*
 397          * Don't attempt to canonicalize names that will be interpreted by
 398          * a proxy or jump host unless the user specifically requests so.
 399          */
 400         if (!direct &&
 401             options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS)
 402                 return 0;
 403         debug3_f("check \"%s\" CNAME \"%s\"", *namep, cname);
 404         for (i = 0; i < options.num_permitted_cnames; i++) {
 405                 rule = options.permitted_cnames + i;
 406                 if (match_pattern_list(*namep, rule->source_list, 1) != 1 ||
 407                     match_pattern_list(cname, rule->target_list, 1) != 1)
 408                         continue;
 409                 verbose("Canonicalized DNS aliased hostname "
 410                     "\"%s\" => \"%s\"", *namep, cname);
 411                 free(*namep);
 412                 *namep = xstrdup(cname);
 413                 return 1;
 414         }
 415         return 0;
 416 }
 417
 418 /*
 419  * Attempt to resolve the supplied hostname after applying the user's
 420  * canonicalization rules. Returns the address list for the host or NULL
 421  * if no name was found after canonicalization.
 422  * NB. this function must operate with a options having undefined members.
 423  */
 424 static struct addrinfo *
 425 resolve_canonicalize(char **hostp, int port)
 426 {
 427         int i, direct, ndots;
 428         char *cp, *fullhost, newname[NI_MAXHOST];
 429         struct addrinfo *addrs;
 430
 431         /*
 432          * Attempt to canonicalise addresses, regardless of
 433          * whether hostname canonicalisation was requested
 434          */
 435         if ((addrs = resolve_addr(*hostp, port,
 436             newname, sizeof(newname))) != NULL) {
 437                 debug2_f("hostname %.100s is address", *hostp);
 438                 if (strcasecmp(*hostp, newname) != 0) {
 439                         debug2_f("canonicalised address \"%s\" => \"%s\"",
 440                             *hostp, newname);
 441                         free(*hostp);
 442                         *hostp = xstrdup(newname);
 443                 }
 444                 return addrs;
 445         }
 446
 447         /*
 448          * If this looks like an address but didn't parse as one, it might
 449          * be an address with an invalid interface scope. Skip further
 450          * attempts at canonicalisation.
 451          */
 452         if (is_addr_fast(*hostp)) {
 453                 debug_f("hostname %.100s is an unrecognised address", *hostp);
 454                 return NULL;
 455         }
 456
 457         if (options.canonicalize_hostname == SSH_CANONICALISE_NO)
 458                 return NULL;
 459
 460         /*
 461          * Don't attempt to canonicalize names that will be interpreted by
 462          * a proxy unless the user specifically requests so.
 463          */
 464         direct = option_clear_or_none(options.proxy_command) &&
 465             option_clear_or_none(options.jump_host);
 466         if (!direct &&
 467             options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS)
 468                 return NULL;
 469
 470         /* If domain name is anchored, then resolve it now */
 471         if ((*hostp)[strlen(*hostp) - 1] == '.') {
 472                 debug3_f("name is fully qualified");
 473                 fullhost = xstrdup(*hostp);
 474                 if ((addrs = resolve_host(fullhost, port, 0,
 475                     newname, sizeof(newname))) != NULL)
 476                         goto found;
 477                 free(fullhost);
 478                 goto notfound;
 479         }
 480
 481         /* Don't apply canonicalization to sufficiently-qualified hostnames */
 482         ndots = 0;
 483         for (cp = *hostp; *cp != '\0'; cp++) {
 484                 if (*cp == '.')
 485                         ndots++;
 486         }
 487         if (ndots > options.canonicalize_max_dots) {
 488                 debug3_f("not canonicalizing hostname \"%s\" (max dots %d)",
 489                     *hostp, options.canonicalize_max_dots);
 490                 return NULL;
 491         }
 492         /* Attempt each supplied suffix */
 493         for (i = 0; i < options.num_canonical_domains; i++) {
 494                 if (strcasecmp(options.canonical_domains[i], "none") == 0)
 495                         break;
 496                 xasprintf(&fullhost, "%s.%s.", *hostp,
 497                     options.canonical_domains[i]);
 498                 debug3_f("attempting \"%s\" => \"%s\"", *hostp, fullhost);
 499                 if ((addrs = resolve_host(fullhost, port, 0,
 500                     newname, sizeof(newname))) == NULL) {
 501                         free(fullhost);
 502                         continue;
 503                 }
 504  found:
 505                 /* Remove trailing '.' */
 506                 fullhost[strlen(fullhost) - 1] = '\0';
 507                 /* Follow CNAME if requested */
 508                 if (!check_follow_cname(direct, &fullhost, newname)) {
 509                         debug("Canonicalized hostname \"%s\" => \"%s\"",
 510                             *hostp, fullhost);
 511                 }
 512                 free(*hostp);
 513                 *hostp = fullhost;
 514                 return addrs;
 515         }
 516  notfound:
 517         if (!options.canonicalize_fallback_local)
 518                 fatal("%s: Could not resolve host \"%s\"", __progname, *hostp);
 519         debug2_f("host %s not found in any suffix", *hostp);
 520         return NULL;
 521 }
 522
 523 /*
 524  * Check the result of hostkey loading, ignoring some errors and either
 525  * discarding the key or fatal()ing for others.
 526  */
 527 static void
 528 check_load(int r, struct sshkey **k, const char *path, const char *message)
 529 {
 530         switch (r) {
 531         case 0:
 532                 /* Check RSA keys size and discard if undersized */
 533                 if (k != NULL && *k != NULL &&
 534                     (r = sshkey_check_rsa_length(*k,
 535                     options.required_rsa_size)) != 0) {
 536                         error_r(r, "load %s \"%s\"", message, path);
 537                         free(*k);
 538                         *k = NULL;
 539                 }
 540                 break;
 541         case SSH_ERR_INTERNAL_ERROR:
 542         case SSH_ERR_ALLOC_FAIL:
 543                 fatal_r(r, "load %s \"%s\"", message, path);
 544         case SSH_ERR_SYSTEM_ERROR:
 545                 /* Ignore missing files */
 546                 if (errno == ENOENT)
 547                         break;
 548                 /* FALLTHROUGH */
 549         default:
 550                 error_r(r, "load %s \"%s\"", message, path);
 551                 break;
 552         }
 553 }
 554
 555 /*
 556  * Read per-user configuration file.  Ignore the system wide config
 557  * file if the user specifies a config file on the command line.
 558  */
 559 static void
 560 process_config_files(const char *host_name, struct passwd *pw, int final_pass,
 561     int *want_final_pass)
 562 {
 563         char buf[PATH_MAX];
 564         int r;
 565
 566         if (config != NULL) {
 567                 if (strcasecmp(config, "none") != 0 &&
 568                     !read_config_file(config, pw, host, host_name, &options,
 569                     SSHCONF_USERCONF | (final_pass ? SSHCONF_FINAL : 0),
 570                     want_final_pass))
 571                         fatal("Can't open user config file %.100s: "
 572                             "%.100s", config, strerror(errno));
 573         } else {
 574                 r = snprintf(buf, sizeof buf, "%s/%s", pw->pw_dir,
 575                     _PATH_SSH_USER_CONFFILE);
 576                 if (r > 0 && (size_t)r < sizeof(buf))
 577                         (void)read_config_file(buf, pw, host, host_name,
 578                             &options, SSHCONF_CHECKPERM | SSHCONF_USERCONF |
 579                             (final_pass ? SSHCONF_FINAL : 0), want_final_pass);
 580
 581                 /* Read systemwide configuration file after user config. */
 582                 (void)read_config_file(_PATH_HOST_CONFIG_FILE, pw,
 583                     host, host_name, &options,
 584                     final_pass ? SSHCONF_FINAL : 0, want_final_pass);
 585         }
 586 }
 587
 588 /* Rewrite the port number in an addrinfo list of addresses */
 589 static void
 590 set_addrinfo_port(struct addrinfo *addrs, int port)
 591 {
 592         struct addrinfo *addr;
 593
 594         for (addr = addrs; addr != NULL; addr = addr->ai_next) {
 595                 switch (addr->ai_family) {
 596                 case AF_INET:
 597                         ((struct sockaddr_in *)addr->ai_addr)->
 598                             sin_port = htons(port);
 599                         break;
 600                 case AF_INET6:
 601                         ((struct sockaddr_in6 *)addr->ai_addr)->
 602                             sin6_port = htons(port);
 603                         break;
 604                 }
 605         }
 606 }
 607
 608 static void
 609 ssh_conn_info_free(struct ssh_conn_info *cinfo)
 610 {
 611         if (cinfo == NULL)
 612                 return;
 613         free(cinfo->conn_hash_hex);
 614         free(cinfo->shorthost);
 615         free(cinfo->uidstr);
 616         free(cinfo->keyalias);
 617         free(cinfo->thishost);
 618         free(cinfo->host_arg);
 619         free(cinfo->portstr);
 620         free(cinfo->remhost);
 621         free(cinfo->remuser);
 622         free(cinfo->homedir);
 623         free(cinfo->locuser);
 624         free(cinfo);
 625 }
 626
 627 /*
 628  * Main program for the ssh client.
 629  */
 630 int
 631 main(int ac, char **av)
 632 {
 633         struct ssh *ssh = NULL;
 634         int i, r, opt, exit_status, use_syslog, direct, timeout_ms;
 635         int was_addr, config_test = 0, opt_terminated = 0, want_final_pass = 0;
 636         char *p, *cp, *line, *argv0, *logfile;
 637         char cname[NI_MAXHOST], thishost[NI_MAXHOST];
 638         struct stat st;
 639         struct passwd *pw;
 640         extern int optind, optreset;
 641         extern char *optarg;
 642         struct Forward fwd;
 643         struct addrinfo *addrs = NULL;
 644         size_t n, len;
 645         u_int j;
 646         struct ssh_conn_info *cinfo = NULL;
 647
 648         /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
 649         sanitise_stdfd();
 650
 651         /*
 652          * Discard other fds that are hanging around. These can cause problem
 653          * with backgrounded ssh processes started by ControlPersist.
 654          */
 655         closefrom(STDERR_FILENO + 1);
 656
 657         __progname = ssh_get_progname(av[0]);
 658
 659 #ifndef HAVE_SETPROCTITLE
 660         /* Prepare for later setproctitle emulation */
 661         /* Save argv so it isn't clobbered by setproctitle() emulation */
 662         saved_av = xcalloc(ac + 1, sizeof(*saved_av));
 663         for (i = 0; i < ac; i++)
 664                 saved_av[i] = xstrdup(av[i]);
 665         saved_av[i] = NULL;
 666         compat_init_setproctitle(ac, av);
 667         av = saved_av;
 668 #endif
 669
 670         seed_rng();
 671
 672         /* Get user data. */
 673         pw = getpwuid(getuid());
 674         if (!pw) {
 675                 logit("No user exists for uid %lu", (u_long)getuid());
 676                 exit(255);
 677         }
 678         /* Take a copy of the returned structure. */
 679         pw = pwcopy(pw);
 680
 681         /*
 682          * Set our umask to something reasonable, as some files are created
 683          * with the default umask.  This will make them world-readable but
 684          * writable only by the owner, which is ok for all files for which we
 685          * don't set the modes explicitly.
 686          */
 687         umask(022 | umask(077));
 688
 689         msetlocale();
 690
 691         /*
 692          * Initialize option structure to indicate that no values have been
 693          * set.
 694          */
 695         initialize_options(&options);
 696
 697         /*
 698          * Prepare main ssh transport/connection structures
 699          */
 700         if ((ssh = ssh_alloc_session_state()) == NULL)
 701                 fatal("Couldn't allocate session state");
 702         channel_init_channels(ssh);
 703
 704         /* Parse command-line arguments. */
 705         host = NULL;
 706         use_syslog = 0;
 707         logfile = NULL;
 708         argv0 = av[0];
 709
 710  again:
 711         while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx"
 712             "AB:CD:E:F:GI:J:KL:MNO:P:Q:R:S:TVw:W:XYy")) != -1) { /* HUZdhjruz */
 713                 switch (opt) {
 714                 case '1':
 715                         fatal("SSH protocol v.1 is no longer supported");
 716                         break;
 717                 case '2':
 718                         /* Ignored */
 719                         break;
 720                 case '4':
 721                         options.address_family = AF_INET;
 722                         break;
 723                 case '6':
 724                         options.address_family = AF_INET6;
 725                         break;
 726                 case 'n':
 727                         options.stdin_null = 1;
 728                         break;
 729                 case 'f':
 730                         options.fork_after_authentication = 1;
 731                         options.stdin_null = 1;
 732                         break;
 733                 case 'x':
 734                         options.forward_x11 = 0;
 735                         break;
 736                 case 'X':
 737                         options.forward_x11 = 1;
 738                         break;
 739                 case 'y':
 740                         use_syslog = 1;
 741                         break;
 742                 case 'E':
 743                         logfile = optarg;
 744                         break;
 745                 case 'G':
 746                         config_test = 1;
 747                         break;
 748                 case 'Y':
 749                         options.forward_x11 = 1;
 750                         options.forward_x11_trusted = 1;
 751                         break;
 752                 case 'g':
 753                         options.fwd_opts.gateway_ports = 1;
 754                         break;
 755                 case 'O':
 756                         if (options.stdio_forward_host != NULL)
 757                                 fatal("Cannot specify multiplexing "
 758                                     "command with -W");
 759                         else if (muxclient_command != 0)
 760                                 fatal("Multiplexing command already specified");
 761                         if (strcmp(optarg, "check") == 0)
 762                                 muxclient_command = SSHMUX_COMMAND_ALIVE_CHECK;
 763                         else if (strcmp(optarg, "forward") == 0)
 764                                 muxclient_command = SSHMUX_COMMAND_FORWARD;
 765                         else if (strcmp(optarg, "exit") == 0)
 766                                 muxclient_command = SSHMUX_COMMAND_TERMINATE;
 767                         else if (strcmp(optarg, "stop") == 0)
 768                                 muxclient_command = SSHMUX_COMMAND_STOP;
 769                         else if (strcmp(optarg, "cancel") == 0)
 770                                 muxclient_command = SSHMUX_COMMAND_CANCEL_FWD;
 771                         else if (strcmp(optarg, "proxy") == 0)
 772                                 muxclient_command = SSHMUX_COMMAND_PROXY;
 773                         else
 774                                 fatal("Invalid multiplex command.");
 775                         break;
 776                 case 'P':
 777                         if (options.tag == NULL)
 778                                 options.tag = xstrdup(optarg);
 779                         break;
 780                 case 'Q':
 781                         cp = NULL;
 782                         if (strcmp(optarg, "cipher") == 0 ||
 783                             strcasecmp(optarg, "Ciphers") == 0)
 784                                 cp = cipher_alg_list('\n', 0);
 785                         else if (strcmp(optarg, "cipher-auth") == 0)
 786                                 cp = cipher_alg_list('\n', 1);
 787                         else if (strcmp(optarg, "mac") == 0 ||
 788                             strcasecmp(optarg, "MACs") == 0)
 789                                 cp = mac_alg_list('\n');
 790                         else if (strcmp(optarg, "kex") == 0 ||
 791                             strcasecmp(optarg, "KexAlgorithms") == 0)
 792                                 cp = kex_alg_list('\n');
 793                         else if (strcmp(optarg, "key") == 0)
 794                                 cp = sshkey_alg_list(0, 0, 0, '\n');
 795                         else if (strcmp(optarg, "key-cert") == 0)
 796                                 cp = sshkey_alg_list(1, 0, 0, '\n');
 797                         else if (strcmp(optarg, "key-plain") == 0)
 798                                 cp = sshkey_alg_list(0, 1, 0, '\n');
 799                         else if (strcmp(optarg, "key-ca-sign") == 0 ||
 800                             strcasecmp(optarg, "CASignatureAlgorithms") == 0)
 801                                 cp = sshkey_alg_list(0, 1, 1, '\n');
 802                         else if (strcmp(optarg, "key-sig") == 0 ||
 803                             strcasecmp(optarg, "PubkeyAcceptedKeyTypes") == 0 || /* deprecated name */
 804                             strcasecmp(optarg, "PubkeyAcceptedAlgorithms") == 0 ||
 805                             strcasecmp(optarg, "HostKeyAlgorithms") == 0 ||
 806                             strcasecmp(optarg, "HostbasedKeyTypes") == 0 || /* deprecated name */
 807                             strcasecmp(optarg, "HostbasedAcceptedKeyTypes") == 0 || /* deprecated name */
 808                             strcasecmp(optarg, "HostbasedAcceptedAlgorithms") == 0)
 809                                 cp = sshkey_alg_list(0, 0, 1, '\n');
 810                         else if (strcmp(optarg, "sig") == 0)
 811                                 cp = sshkey_alg_list(0, 1, 1, '\n');
 812                         else if (strcmp(optarg, "protocol-version") == 0)
 813                                 cp = xstrdup("2");
 814                         else if (strcmp(optarg, "compression") == 0) {
 815                                 cp = xstrdup(compression_alg_list(0));
 816                                 len = strlen(cp);
 817                                 for (n = 0; n < len; n++)
 818                                         if (cp[n] == ',')
 819                                                 cp[n] = '\n';
 820                         } else if (strcmp(optarg, "help") == 0) {
 821                                 cp = xstrdup(
 822                                     "cipher\ncipher-auth\ncompression\nkex\n"
 823                                     "key\nkey-cert\nkey-plain\nkey-sig\nmac\n"
 824                                     "protocol-version\nsig");
 825                         }
 826                         if (cp == NULL)
 827                                 fatal("Unsupported query \"%s\"", optarg);
 828                         printf("%s\n", cp);
 829                         free(cp);
 830                         exit(0);
 831                         break;
 832                 case 'a':
 833                         options.forward_agent = 0;
 834                         break;
 835                 case 'A':
 836                         options.forward_agent = 1;
 837                         break;
 838                 case 'k':
 839                         options.gss_deleg_creds = 0;
 840                         break;
 841                 case 'K':
 842                         options.gss_authentication = 1;
 843                         options.gss_deleg_creds = 1;
 844                         break;
 845                 case 'i':
 846                         p = tilde_expand_filename(optarg, getuid());
 847                         if (stat(p, &st) == -1)
 848                                 fprintf(stderr, "Warning: Identity file %s "
 849                                     "not accessible: %s.\n", p,
 850                                     strerror(errno));
 851                         else
 852                                 add_identity_file(&options, NULL, p, 1);
 853                         free(p);
 854                         break;
 855                 case 'I':
 856 #ifdef ENABLE_PKCS11
 857                         free(options.pkcs11_provider);
 858                         options.pkcs11_provider = xstrdup(optarg);
 859 #else
 860                         fprintf(stderr, "no support for PKCS#11.\n");
 861 #endif
 862                         break;
 863                 case 'J':
 864                         if (options.jump_host != NULL) {
 865                                 fatal("Only a single -J option is permitted "
 866                                     "(use commas to separate multiple "
 867                                     "jump hops)");
 868                         }
 869                         if (options.proxy_command != NULL)
 870                                 fatal("Cannot specify -J with ProxyCommand");
 871                         if (parse_jump(optarg, &options, 1) == -1)
 872                                 fatal("Invalid -J argument");
 873                         options.proxy_command = xstrdup("none");
 874                         break;
 875                 case 't':
 876                         if (options.request_tty == REQUEST_TTY_YES)
 877                                 options.request_tty = REQUEST_TTY_FORCE;
 878                         else
 879                                 options.request_tty = REQUEST_TTY_YES;
 880                         break;
 881                 case 'v':
 882                         if (debug_flag == 0) {
 883                                 debug_flag = 1;
 884                                 options.log_level = SYSLOG_LEVEL_DEBUG1;
 885                         } else {
 886                                 if (options.log_level < SYSLOG_LEVEL_DEBUG3) {
 887                                         debug_flag++;
 888                                         options.log_level++;
 889                                 }
 890                         }
 891                         break;
 892                 case 'V':
 893                         fprintf(stderr, "%s, %s\n",
 894                             SSH_RELEASE, SSH_OPENSSL_VERSION);
 895                         exit(0);
 896                         break;
 897                 case 'w':
 898                         if (options.tun_open == -1)
 899                                 options.tun_open = SSH_TUNMODE_DEFAULT;
 900                         options.tun_local = a2tun(optarg, &options.tun_remote);
 901                         if (options.tun_local == SSH_TUNID_ERR) {
 902                                 fprintf(stderr,
 903                                     "Bad tun device '%s'\n", optarg);
 904                                 exit(255);
 905                         }
 906                         break;
 907                 case 'W':
 908                         if (options.stdio_forward_host != NULL)
 909                                 fatal("stdio forward already specified");
 910                         if (muxclient_command != 0)
 911                                 fatal("Cannot specify stdio forward with -O");
 912                         if (parse_forward(&fwd, optarg, 1, 0)) {
 913                                 options.stdio_forward_host =
 914                                     fwd.listen_port == PORT_STREAMLOCAL ?
 915                                     fwd.listen_path : fwd.listen_host;
 916                                 options.stdio_forward_port = fwd.listen_port;
 917                                 free(fwd.connect_host);
 918                         } else {
 919                                 fprintf(stderr,
 920                                     "Bad stdio forwarding specification '%s'\n",
 921                                     optarg);
 922                                 exit(255);
 923                         }
 924                         options.request_tty = REQUEST_TTY_NO;
 925                         options.session_type = SESSION_TYPE_NONE;
 926                         break;
 927                 case 'q':
 928                         options.log_level = SYSLOG_LEVEL_QUIET;
 929                         break;
 930                 case 'e':
 931                         if (optarg[0] == '^' && optarg[2] == 0 &&
 932                             (u_char) optarg[1] >= 64 &&
 933                             (u_char) optarg[1] < 128)
 934                                 options.escape_char = (u_char) optarg[1] & 31;
 935                         else if (strlen(optarg) == 1)
 936                                 options.escape_char = (u_char) optarg[0];
 937                         else if (strcmp(optarg, "none") == 0)
 938                                 options.escape_char = SSH_ESCAPECHAR_NONE;
 939                         else {
 940                                 fprintf(stderr, "Bad escape character '%s'.\n",
 941                                     optarg);
 942                                 exit(255);
 943                         }
 944                         break;
 945                 case 'c':
 946                         if (!ciphers_valid(*optarg == '+' || *optarg == '^' ?
 947                             optarg + 1 : optarg)) {
 948                                 fprintf(stderr, "Unknown cipher type '%s'\n",
 949                                     optarg);
 950                                 exit(255);
 951                         }
 952                         free(options.ciphers);
 953                         options.ciphers = xstrdup(optarg);
 954                         break;
 955                 case 'm':
 956                         if (mac_valid(optarg)) {
 957                                 free(options.macs);
 958                                 options.macs = xstrdup(optarg);
 959                         } else {
 960                                 fprintf(stderr, "Unknown mac type '%s'\n",
 961                                     optarg);
 962                                 exit(255);
 963                         }
 964                         break;
 965                 case 'M':
 966                         if (options.control_master == SSHCTL_MASTER_YES)
 967                                 options.control_master = SSHCTL_MASTER_ASK;
 968                         else
 969                                 options.control_master = SSHCTL_MASTER_YES;
 970                         break;
 971                 case 'p':
 972                         if (options.port == -1) {
 973                                 options.port = a2port(optarg);
 974                                 if (options.port <= 0) {
 975                                         fprintf(stderr, "Bad port '%s'\n",
 976                                             optarg);
 977                                         exit(255);
 978                                 }
 979                         }
 980                         break;
 981                 case 'l':
 982                         if (options.user == NULL)
 983                                 options.user = optarg;
 984                         break;
 985
 986                 case 'L':
 987                         if (parse_forward(&fwd, optarg, 0, 0))
 988                                 add_local_forward(&options, &fwd);
 989                         else {
 990                                 fprintf(stderr,
 991                                     "Bad local forwarding specification '%s'\n",
 992                                     optarg);
 993                                 exit(255);
 994                         }
 995                         break;
 996
 997                 case 'R':
 998                         if (parse_forward(&fwd, optarg, 0, 1) ||
 999                             parse_forward(&fwd, optarg, 1, 1)) {
1000                                 add_remote_forward(&options, &fwd);
1001                         } else {
1002                                 fprintf(stderr,
1003                                     "Bad remote forwarding specification "
1004                                     "'%s'\n", optarg);
1005                                 exit(255);
1006                         }
1007                         break;
1008
1009                 case 'D':
1010                         if (parse_forward(&fwd, optarg, 1, 0)) {
1011                                 add_local_forward(&options, &fwd);
1012                         } else {
1013                                 fprintf(stderr,
1014                                     "Bad dynamic forwarding specification "
1015                                     "'%s'\n", optarg);
1016                                 exit(255);
1017                         }
1018                         break;
1019
1020                 case 'C':
1021 #ifdef WITH_ZLIB
1022                         options.compression = 1;
1023 #else
1024                         error("Compression not supported, disabling.");
1025 #endif
1026                         break;
1027                 case 'N':
1028                         if (options.session_type != -1 &&
1029                             options.session_type != SESSION_TYPE_NONE)
1030                                 fatal("Cannot specify -N with -s/SessionType");
1031                         options.session_type = SESSION_TYPE_NONE;
1032                         options.request_tty = REQUEST_TTY_NO;
1033                         break;
1034                 case 'T':
1035                         options.request_tty = REQUEST_TTY_NO;
1036                         break;
1037                 case 'o':
1038                         line = xstrdup(optarg);
1039                         if (process_config_line(&options, pw,
1040                             host ? host : "", host ? host : "", line,
1041                             "command-line", 0, NULL, SSHCONF_USERCONF) != 0)
1042                                 exit(255);
1043                         free(line);
1044                         break;
1045                 case 's':
1046                         if (options.session_type != -1 &&
1047                             options.session_type != SESSION_TYPE_SUBSYSTEM)
1048                                 fatal("Cannot specify -s with -N/SessionType");
1049                         options.session_type = SESSION_TYPE_SUBSYSTEM;
1050                         break;
1051                 case 'S':
1052                         free(options.control_path);
1053                         options.control_path = xstrdup(optarg);
1054                         break;
1055                 case 'b':
1056                         options.bind_address = optarg;
1057                         break;
1058                 case 'B':
1059                         options.bind_interface = optarg;
1060                         break;
1061                 case 'F':
1062                         config = optarg;
1063                         break;
1064                 default:
1065                         usage();
1066                 }
1067         }
1068
1069         if (optind > 1 && strcmp(av[optind - 1], "--") == 0)
1070                 opt_terminated = 1;
1071
1072         ac -= optind;
1073         av += optind;
1074
1075         if (ac > 0 && !host) {
1076                 int tport;
1077                 char *tuser;
1078                 switch (parse_ssh_uri(*av, &tuser, &host, &tport)) {
1079                 case -1:
1080                         usage();
1081                         break;
1082                 case 0:
1083                         if (options.user == NULL) {
1084                                 options.user = tuser;
1085                                 tuser = NULL;
1086                         }
1087                         free(tuser);
1088                         if (options.port == -1 && tport != -1)
1089                                 options.port = tport;
1090                         break;
1091                 default:
1092                         p = xstrdup(*av);
1093                         cp = strrchr(p, '@');
1094                         if (cp != NULL) {
1095                                 if (cp == p)
1096                                         usage();
1097                                 if (options.user == NULL) {
1098                                         options.user = p;
1099                                         p = NULL;
1100                                 }
1101                                 *cp++ = '\0';
1102                                 host = xstrdup(cp);
1103                                 free(p);
1104                         } else
1105                                 host = p;
1106                         break;
1107                 }
1108                 if (ac > 1 && !opt_terminated) {
1109                         optind = optreset = 1;
1110                         goto again;
1111                 }
1112                 ac--, av++;
1113         }
1114
1115         /* Check that we got a host name. */
1116         if (!host)
1117                 usage();
1118
1119         options.host_arg = xstrdup(host);
1120
1121         /* Initialize the command to execute on remote host. */
1122         if ((command = sshbuf_new()) == NULL)
1123                 fatal("sshbuf_new failed");
1124
1125         /*
1126          * Save the command to execute on the remote host in a buffer. There
1127          * is no limit on the length of the command, except by the maximum
1128          * packet size.  Also sets the tty flag if there is no command.
1129          */
1130         if (!ac) {
1131                 /* No command specified - execute shell on a tty. */
1132                 if (options.session_type == SESSION_TYPE_SUBSYSTEM) {
1133                         fprintf(stderr,
1134                             "You must specify a subsystem to invoke.\n");
1135                         usage();
1136                 }
1137         } else {
1138                 /* A command has been specified.  Store it into the buffer. */
1139                 for (i = 0; i < ac; i++) {
1140                         if ((r = sshbuf_putf(command, "%s%s",
1141                             i ? " " : "", av[i])) != 0)
1142                                 fatal_fr(r, "buffer error");
1143                 }
1144         }
1145
1146         ssh_signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */
1147
1148         /*
1149          * Initialize "log" output.  Since we are the client all output
1150          * goes to stderr unless otherwise specified by -y or -E.
1151          */
1152         if (use_syslog && logfile != NULL)
1153                 fatal("Can't specify both -y and -E");
1154         if (logfile != NULL)
1155                 log_redirect_stderr_to(logfile);
1156         log_init(argv0,
1157             options.log_level == SYSLOG_LEVEL_NOT_SET ?
1158             SYSLOG_LEVEL_INFO : options.log_level,
1159             options.log_facility == SYSLOG_FACILITY_NOT_SET ?
1160             SYSLOG_FACILITY_USER : options.log_facility,
1161             !use_syslog);
1162
1163         if (debug_flag)
1164                 logit("%s, %s", SSH_RELEASE, SSH_OPENSSL_VERSION);
1165
1166         /* Parse the configuration files */
1167         process_config_files(options.host_arg, pw, 0, &want_final_pass);
1168         if (want_final_pass)
1169                 debug("configuration requests final Match pass");
1170
1171         /* Hostname canonicalisation needs a few options filled. */
1172         fill_default_options_for_canonicalization(&options);
1173
1174         /* If the user has replaced the hostname then take it into use now */
1175         if (options.hostname != NULL) {
1176                 /* NB. Please keep in sync with readconf.c:match_cfg_line() */
1177                 cp = percent_expand(options.hostname,
1178                     "h", host, (char *)NULL);
1179                 free(host);
1180                 host = cp;
1181                 free(options.hostname);
1182                 options.hostname = xstrdup(host);
1183         }
1184
1185         /* Don't lowercase addresses, they will be explicitly canonicalised */
1186         if ((was_addr = is_addr(host)) == 0)
1187                 lowercase(host);
1188
1189         /*
1190          * Try to canonicalize if requested by configuration or the
1191          * hostname is an address.
1192          */
1193         if (options.canonicalize_hostname != SSH_CANONICALISE_NO || was_addr)
1194                 addrs = resolve_canonicalize(&host, options.port);
1195
1196         /*
1197          * If CanonicalizePermittedCNAMEs have been specified but
1198          * other canonicalization did not happen (by not being requested
1199          * or by failing with fallback) then the hostname may still be changed
1200          * as a result of CNAME following.
1201          *
1202          * Try to resolve the bare hostname name using the system resolver's
1203          * usual search rules and then apply the CNAME follow rules.
1204          *
1205          * Skip the lookup if a ProxyCommand is being used unless the user
1206          * has specifically requested canonicalisation for this case via
1207          * CanonicalizeHostname=always
1208          */
1209         direct = option_clear_or_none(options.proxy_command) &&
1210             option_clear_or_none(options.jump_host);
1211         if (addrs == NULL && config_has_permitted_cnames(&options) && (direct ||
1212             options.canonicalize_hostname == SSH_CANONICALISE_ALWAYS)) {
1213                 if ((addrs = resolve_host(host, options.port,
1214                     direct, cname, sizeof(cname))) == NULL) {
1215                         /* Don't fatal proxied host names not in the DNS */
1216                         if (direct)
1217                                 cleanup_exit(255); /* logged in resolve_host */
1218                 } else
1219                         check_follow_cname(direct, &host, cname);
1220         }
1221
1222         /*
1223          * If canonicalisation is enabled then re-parse the configuration
1224          * files as new stanzas may match.
1225          */
1226         if (options.canonicalize_hostname != 0 && !want_final_pass) {
1227                 debug("hostname canonicalisation enabled, "
1228                     "will re-parse configuration");
1229                 want_final_pass = 1;
1230         }
1231
1232         if (want_final_pass) {
1233                 debug("re-parsing configuration");
1234                 free(options.hostname);
1235                 options.hostname = xstrdup(host);
1236                 process_config_files(options.host_arg, pw, 1, NULL);
1237                 /*
1238                  * Address resolution happens early with canonicalisation
1239                  * enabled and the port number may have changed since, so
1240                  * reset it in address list
1241                  */
1242                 if (addrs != NULL && options.port > 0)
1243                         set_addrinfo_port(addrs, options.port);
1244         }
1245
1246         /* Fill configuration defaults. */
1247         if (fill_default_options(&options) != 0)
1248                 cleanup_exit(255);
1249
1250         if (options.user == NULL)
1251                 options.user = xstrdup(pw->pw_name);
1252
1253         /*
1254          * If ProxyJump option specified, then construct a ProxyCommand now.
1255          */
1256         if (options.jump_host != NULL) {
1257                 char port_s[8];
1258                 const char *jumpuser = options.jump_user, *sshbin = argv0;
1259                 int port = options.port, jumpport = options.jump_port;
1260
1261                 if (port <= 0)
1262                         port = default_ssh_port();
1263                 if (jumpport <= 0)
1264                         jumpport = default_ssh_port();
1265                 if (jumpuser == NULL)
1266                         jumpuser = options.user;
1267                 if (strcmp(options.jump_host, host) == 0 && port == jumpport &&
1268                     strcmp(options.user, jumpuser) == 0)
1269                         fatal("jumphost loop via %s", options.jump_host);
1270
1271                 /*
1272                  * Try to use SSH indicated by argv[0], but fall back to
1273                  * "ssh" if it appears unavailable.
1274                  */
1275                 if (strchr(argv0, '/') != NULL && access(argv0, X_OK) != 0)
1276                         sshbin = "ssh";
1277
1278                 /* Consistency check */
1279                 if (options.proxy_command != NULL)
1280                         fatal("inconsistent options: ProxyCommand+ProxyJump");
1281                 /* Never use FD passing for ProxyJump */
1282                 options.proxy_use_fdpass = 0;
1283                 snprintf(port_s, sizeof(port_s), "%d", options.jump_port);
1284                 xasprintf(&options.proxy_command,
1285                     "%s%s%s%s%s%s%s%s%s%s%.*s -W '[%%h]:%%p' %s",
1286                     sshbin,
1287                     /* Optional "-l user" argument if jump_user set */
1288                     options.jump_user == NULL ? "" : " -l ",
1289                     options.jump_user == NULL ? "" : options.jump_user,
1290                     /* Optional "-p port" argument if jump_port set */
1291                     options.jump_port <= 0 ? "" : " -p ",
1292                     options.jump_port <= 0 ? "" : port_s,
1293                     /* Optional additional jump hosts ",..." */
1294                     options.jump_extra == NULL ? "" : " -J ",
1295                     options.jump_extra == NULL ? "" : options.jump_extra,
1296                     /* Optional "-F" argument if -F specified */
1297                     config == NULL ? "" : " -F ",
1298                     config == NULL ? "" : config,
1299                     /* Optional "-v" arguments if -v set */
1300                     debug_flag ? " -" : "",
1301                     debug_flag, "vvv",
1302                     /* Mandatory hostname */
1303                     options.jump_host);
1304                 debug("Setting implicit ProxyCommand from ProxyJump: %s",
1305                     options.proxy_command);
1306         }
1307
1308         if (options.port == 0)
1309                 options.port = default_ssh_port();
1310         channel_set_af(ssh, options.address_family);
1311
1312         /* Tidy and check options */
1313         if (options.host_key_alias != NULL)
1314                 lowercase(options.host_key_alias);
1315         if (options.proxy_command != NULL &&
1316             strcmp(options.proxy_command, "-") == 0 &&
1317             options.proxy_use_fdpass)
1318                 fatal("ProxyCommand=- and ProxyUseFDPass are incompatible");
1319         if (options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK) {
1320                 if (options.control_persist && options.control_path != NULL) {
1321                         debug("UpdateHostKeys=ask is incompatible with "
1322                             "ControlPersist; disabling");
1323                         options.update_hostkeys = 0;
1324                 } else if (sshbuf_len(command) != 0 ||
1325                     options.remote_command != NULL ||
1326                     options.request_tty == REQUEST_TTY_NO) {
1327                         debug("UpdateHostKeys=ask is incompatible with "
1328                             "remote command execution; disabling");
1329                         options.update_hostkeys = 0;
1330                 } else if (options.log_level < SYSLOG_LEVEL_INFO) {
1331                         /* no point logging anything; user won't see it */
1332                         options.update_hostkeys = 0;
1333                 }
1334         }
1335         if (options.connection_attempts <= 0)
1336                 fatal("Invalid number of ConnectionAttempts");
1337
1338         if (sshbuf_len(command) != 0 && options.remote_command != NULL)
1339                 fatal("Cannot execute command-line and remote command.");
1340
1341         /* Cannot fork to background if no command. */
1342         if (options.fork_after_authentication && sshbuf_len(command) == 0 &&
1343             options.remote_command == NULL &&
1344             options.session_type != SESSION_TYPE_NONE)
1345                 fatal("Cannot fork into background without a command "
1346                     "to execute.");
1347
1348         /* reinit */
1349         log_init(argv0, options.log_level, options.log_facility, !use_syslog);
1350         for (j = 0; j < options.num_log_verbose; j++) {
1351                 if (strcasecmp(options.log_verbose[j], "none") == 0)
1352                         break;
1353                 log_verbose_add(options.log_verbose[j]);
1354         }
1355
1356         if (options.request_tty == REQUEST_TTY_YES ||
1357             options.request_tty == REQUEST_TTY_FORCE)
1358                 tty_flag = 1;
1359
1360         /* Allocate a tty by default if no command specified. */
1361         if (sshbuf_len(command) == 0 && options.remote_command == NULL)
1362                 tty_flag = options.request_tty != REQUEST_TTY_NO;
1363
1364         /* Force no tty */
1365         if (options.request_tty == REQUEST_TTY_NO ||
1366             (muxclient_command && muxclient_command != SSHMUX_COMMAND_PROXY) ||
1367             options.session_type == SESSION_TYPE_NONE)
1368                 tty_flag = 0;
1369         /* Do not allocate a tty if stdin is not a tty. */
1370         if ((!isatty(fileno(stdin)) || options.stdin_null) &&
1371             options.request_tty != REQUEST_TTY_FORCE) {
1372                 if (tty_flag)
1373                         logit("Pseudo-terminal will not be allocated because "
1374                             "stdin is not a terminal.");
1375                 tty_flag = 0;
1376         }
1377
1378         /* Set up strings used to percent_expand() arguments */
1379         cinfo = xcalloc(1, sizeof(*cinfo));
1380         if (gethostname(thishost, sizeof(thishost)) == -1)
1381                 fatal("gethostname: %s", strerror(errno));
1382         cinfo->thishost = xstrdup(thishost);
1383         thishost[strcspn(thishost, ".")] = '\0';
1384         cinfo->shorthost = xstrdup(thishost);
1385         xasprintf(&cinfo->portstr, "%d", options.port);
1386         xasprintf(&cinfo->uidstr, "%llu",
1387             (unsigned long long)pw->pw_uid);
1388         cinfo->keyalias = xstrdup(options.host_key_alias ?
1389             options.host_key_alias : options.host_arg);
1390         cinfo->conn_hash_hex = ssh_connection_hash(cinfo->thishost, host,
1391             cinfo->portstr, options.user);
1392         cinfo->host_arg = xstrdup(options.host_arg);
1393         cinfo->remhost = xstrdup(host);
1394         cinfo->remuser = xstrdup(options.user);
1395         cinfo->homedir = xstrdup(pw->pw_dir);
1396         cinfo->locuser = xstrdup(pw->pw_name);
1397
1398         /* Find canonic host name. */
1399         if (strchr(host, '.') == NULL) {
1400                 struct addrinfo hints;
1401                 struct addrinfo *ai = NULL;
1402                 int errgai;
1403
1404                 memset(&hints, 0, sizeof(hints));
1405                 hints.ai_family = options.address_family;
1406                 hints.ai_flags = AI_CANONNAME;
1407                 hints.ai_socktype = SOCK_STREAM;
1408                 errgai = getaddrinfo(host, NULL, &hints, &ai);
1409                 if (errgai == 0) {
1410                         if (ai->ai_canonname != NULL) {
1411                                 free(host);
1412                                 host = xstrdup(ai->ai_canonname);
1413                         }
1414                         freeaddrinfo(ai);
1415                 }
1416         }
1417
1418         /*
1419          * Expand tokens in arguments. NB. LocalCommand is expanded later,
1420          * after port-forwarding is set up, so it may pick up any local
1421          * tunnel interface name allocated.
1422          */
1423         if (options.remote_command != NULL) {
1424                 debug3("expanding RemoteCommand: %s", options.remote_command);
1425                 cp = options.remote_command;
1426                 options.remote_command = default_client_percent_expand(cp,
1427                     cinfo);
1428                 debug3("expanded RemoteCommand: %s", options.remote_command);
1429                 free(cp);
1430                 if ((r = sshbuf_put(command, options.remote_command,
1431                     strlen(options.remote_command))) != 0)
1432                         fatal_fr(r, "buffer error");
1433         }
1434
1435         if (options.control_path != NULL) {
1436                 cp = tilde_expand_filename(options.control_path, getuid());
1437                 free(options.control_path);
1438                 options.control_path = default_client_percent_dollar_expand(cp,
1439                     cinfo);
1440                 free(cp);
1441         }
1442
1443         if (options.identity_agent != NULL) {
1444                 p = tilde_expand_filename(options.identity_agent, getuid());
1445                 cp = default_client_percent_dollar_expand(p, cinfo);
1446                 free(p);
1447                 free(options.identity_agent);
1448                 options.identity_agent = cp;
1449         }
1450
1451         if (options.revoked_host_keys != NULL) {
1452                 p = tilde_expand_filename(options.revoked_host_keys, getuid());
1453                 cp = default_client_percent_dollar_expand(p, cinfo);
1454                 free(p);
1455                 free(options.revoked_host_keys);
1456                 options.revoked_host_keys = cp;
1457         }
1458
1459         if (options.forward_agent_sock_path != NULL) {
1460                 p = tilde_expand_filename(options.forward_agent_sock_path,
1461                     getuid());
1462                 cp = default_client_percent_dollar_expand(p, cinfo);
1463                 free(p);
1464                 free(options.forward_agent_sock_path);
1465                 options.forward_agent_sock_path = cp;
1466                 if (stat(options.forward_agent_sock_path, &st) != 0) {
1467                         error("Cannot forward agent socket path \"%s\": %s",
1468                             options.forward_agent_sock_path, strerror(errno));
1469                         if (options.exit_on_forward_failure)
1470                                 cleanup_exit(255);
1471                 }
1472         }
1473
1474         if (options.num_system_hostfiles > 0 &&
1475             strcasecmp(options.system_hostfiles[0], "none") == 0) {
1476                 if (options.num_system_hostfiles > 1)
1477                         fatal("Invalid GlobalKnownHostsFiles: \"none\" "
1478                             "appears with other entries");
1479                 free(options.system_hostfiles[0]);
1480                 options.system_hostfiles[0] = NULL;
1481                 options.num_system_hostfiles = 0;
1482         }
1483
1484         if (options.num_user_hostfiles > 0 &&
1485             strcasecmp(options.user_hostfiles[0], "none") == 0) {
1486                 if (options.num_user_hostfiles > 1)
1487                         fatal("Invalid UserKnownHostsFiles: \"none\" "
1488                             "appears with other entries");
1489                 free(options.user_hostfiles[0]);
1490                 options.user_hostfiles[0] = NULL;
1491                 options.num_user_hostfiles = 0;
1492         }
1493         for (j = 0; j < options.num_user_hostfiles; j++) {
1494                 if (options.user_hostfiles[j] == NULL)
1495                         continue;
1496                 cp = tilde_expand_filename(options.user_hostfiles[j], getuid());
1497                 p = default_client_percent_dollar_expand(cp, cinfo);
1498                 if (strcmp(options.user_hostfiles[j], p) != 0)
1499                         debug3("expanded UserKnownHostsFile '%s' -> "
1500                             "'%s'", options.user_hostfiles[j], p);
1501                 free(options.user_hostfiles[j]);
1502                 free(cp);
1503                 options.user_hostfiles[j] = p;
1504         }
1505
1506         for (i = 0; i < options.num_local_forwards; i++) {
1507                 if (options.local_forwards[i].listen_path != NULL) {
1508                         cp = options.local_forwards[i].listen_path;
1509                         p = options.local_forwards[i].listen_path =
1510                             default_client_percent_expand(cp, cinfo);
1511                         if (strcmp(cp, p) != 0)
1512                                 debug3("expanded LocalForward listen path "
1513                                     "'%s' -> '%s'", cp, p);
1514                         free(cp);
1515                 }
1516                 if (options.local_forwards[i].connect_path != NULL) {
1517                         cp = options.local_forwards[i].connect_path;
1518                         p = options.local_forwards[i].connect_path =
1519                             default_client_percent_expand(cp, cinfo);
1520                         if (strcmp(cp, p) != 0)
1521                                 debug3("expanded LocalForward connect path "
1522                                     "'%s' -> '%s'", cp, p);
1523                         free(cp);
1524                 }
1525         }
1526
1527         for (i = 0; i < options.num_remote_forwards; i++) {
1528                 if (options.remote_forwards[i].listen_path != NULL) {
1529                         cp = options.remote_forwards[i].listen_path;
1530                         p = options.remote_forwards[i].listen_path =
1531                             default_client_percent_expand(cp, cinfo);
1532                         if (strcmp(cp, p) != 0)
1533                                 debug3("expanded RemoteForward listen path "
1534                                     "'%s' -> '%s'", cp, p);
1535                         free(cp);
1536                 }
1537                 if (options.remote_forwards[i].connect_path != NULL) {
1538                         cp = options.remote_forwards[i].connect_path;
1539                         p = options.remote_forwards[i].connect_path =
1540                             default_client_percent_expand(cp, cinfo);
1541                         if (strcmp(cp, p) != 0)
1542                                 debug3("expanded RemoteForward connect path "
1543                                     "'%s' -> '%s'", cp, p);
1544                         free(cp);
1545                 }
1546         }
1547
1548         if (config_test) {
1549                 dump_client_config(&options, host);
1550                 exit(0);
1551         }
1552
1553         /* Expand SecurityKeyProvider if it refers to an environment variable */
1554         if (options.sk_provider != NULL && *options.sk_provider == '$' &&
1555             strlen(options.sk_provider) > 1) {
1556                 if ((cp = getenv(options.sk_provider + 1)) == NULL) {
1557                         debug("Authenticator provider %s did not resolve; "
1558                             "disabling", options.sk_provider);
1559                         free(options.sk_provider);
1560                         options.sk_provider = NULL;
1561                 } else {
1562                         debug2("resolved SecurityKeyProvider %s => %s",
1563                             options.sk_provider, cp);
1564                         free(options.sk_provider);
1565                         options.sk_provider = xstrdup(cp);
1566                 }
1567         }
1568
1569         if (muxclient_command != 0 && options.control_path == NULL)
1570                 fatal("No ControlPath specified for \"-O\" command");
1571         if (options.control_path != NULL) {
1572                 int sock;
1573                 if ((sock = muxclient(options.control_path)) >= 0) {
1574                         ssh_packet_set_connection(ssh, sock, sock);
1575                         ssh_packet_set_mux(ssh);
1576                         goto skip_connect;
1577                 }
1578         }
1579
1580         /*
1581          * If hostname canonicalisation was not enabled, then we may not
1582          * have yet resolved the hostname. Do so now.
1583          */
1584         if (addrs == NULL && options.proxy_command == NULL) {
1585                 debug2("resolving \"%s\" port %d", host, options.port);
1586                 if ((addrs = resolve_host(host, options.port, 1,
1587                     cname, sizeof(cname))) == NULL)
1588                         cleanup_exit(255); /* resolve_host logs the error */
1589         }
1590
1591         if (options.connection_timeout >= INT_MAX/1000)
1592                 timeout_ms = INT_MAX;
1593         else
1594                 timeout_ms = options.connection_timeout * 1000;
1595
1596         /* Open a connection to the remote host. */
1597         if (ssh_connect(ssh, host, options.host_arg, addrs, &hostaddr,
1598             options.port, options.connection_attempts,
1599             &timeout_ms, options.tcp_keep_alive) != 0)
1600                 exit(255);
1601
1602         if (addrs != NULL)
1603                 freeaddrinfo(addrs);
1604
1605         ssh_packet_set_timeout(ssh, options.server_alive_interval,
1606             options.server_alive_count_max);
1607
1608         if (timeout_ms > 0)
1609                 debug3("timeout: %d ms remain after connect", timeout_ms);
1610
1611         /*
1612          * If we successfully made the connection and we have hostbased auth
1613          * enabled, load the public keys so we can later use the ssh-keysign
1614          * helper to sign challenges.
1615          */
1616         sensitive_data.nkeys = 0;
1617         sensitive_data.keys = NULL;
1618         if (options.hostbased_authentication) {
1619                 int loaded = 0;
1620
1621                 sensitive_data.nkeys = 10;
1622                 sensitive_data.keys = xcalloc(sensitive_data.nkeys,
1623                     sizeof(*sensitive_data.keys));
1624
1625                 /* XXX check errors? */
1626 #define L_PUBKEY(p,o) do { \
1627         if ((o) >= sensitive_data.nkeys) \
1628                 fatal_f("pubkey out of array bounds"); \
1629         check_load(sshkey_load_public(p, &(sensitive_data.keys[o]), NULL), \
1630             &(sensitive_data.keys[o]), p, "pubkey"); \
1631         if (sensitive_data.keys[o] != NULL) { \
1632                 debug2("hostbased key %d: %s key from \"%s\"", o, \
1633                     sshkey_ssh_name(sensitive_data.keys[o]), p); \
1634                 loaded++; \
1635         } \
1636 } while (0)
1637 #define L_CERT(p,o) do { \
1638         if ((o) >= sensitive_data.nkeys) \
1639                 fatal_f("cert out of array bounds"); \
1640         check_load(sshkey_load_cert(p, &(sensitive_data.keys[o])), \
1641             &(sensitive_data.keys[o]), p, "cert"); \
1642         if (sensitive_data.keys[o] != NULL) { \
1643                 debug2("hostbased key %d: %s cert from \"%s\"", o, \
1644                     sshkey_ssh_name(sensitive_data.keys[o]), p); \
1645                 loaded++; \
1646         } \
1647 } while (0)
1648
1649                 if (options.hostbased_authentication == 1) {
1650                         L_CERT(_PATH_HOST_ECDSA_KEY_FILE, 0);
1651                         L_CERT(_PATH_HOST_ED25519_KEY_FILE, 1);
1652                         L_CERT(_PATH_HOST_RSA_KEY_FILE, 2);
1653                         L_CERT(_PATH_HOST_DSA_KEY_FILE, 3);
1654                         L_PUBKEY(_PATH_HOST_ECDSA_KEY_FILE, 4);
1655                         L_PUBKEY(_PATH_HOST_ED25519_KEY_FILE, 5);
1656                         L_PUBKEY(_PATH_HOST_RSA_KEY_FILE, 6);
1657                         L_PUBKEY(_PATH_HOST_DSA_KEY_FILE, 7);
1658                         L_CERT(_PATH_HOST_XMSS_KEY_FILE, 8);
1659                         L_PUBKEY(_PATH_HOST_XMSS_KEY_FILE, 9);
1660                         if (loaded == 0)
1661                                 debug("HostbasedAuthentication enabled but no "
1662                                    "local public host keys could be loaded.");
1663                 }
1664         }
1665
1666         /* load options.identity_files */
1667         load_public_identity_files(cinfo);
1668
1669         /* optionally set the SSH_AUTHSOCKET_ENV_NAME variable */
1670         if (options.identity_agent &&
1671             strcmp(options.identity_agent, SSH_AUTHSOCKET_ENV_NAME) != 0) {
1672                 if (strcmp(options.identity_agent, "none") == 0) {
1673                         unsetenv(SSH_AUTHSOCKET_ENV_NAME);
1674                 } else {
1675                         cp = options.identity_agent;
1676                         /* legacy (limited) format */
1677                         if (cp[0] == '$' && cp[1] != '{') {
1678                                 if (!valid_env_name(cp + 1)) {
1679                                         fatal("Invalid IdentityAgent "
1680                                             "environment variable name %s", cp);
1681                                 }
1682                                 if ((p = getenv(cp + 1)) == NULL)
1683                                         unsetenv(SSH_AUTHSOCKET_ENV_NAME);
1684                                 else
1685                                         setenv(SSH_AUTHSOCKET_ENV_NAME, p, 1);
1686                         } else {
1687                                 /* identity_agent specifies a path directly */
1688                                 setenv(SSH_AUTHSOCKET_ENV_NAME, cp, 1);
1689                         }
1690                 }
1691         }
1692
1693         if (options.forward_agent && options.forward_agent_sock_path != NULL) {
1694                 cp = options.forward_agent_sock_path;
1695                 if (cp[0] == '$') {
1696                         if (!valid_env_name(cp + 1)) {
1697                                 fatal("Invalid ForwardAgent environment variable name %s", cp);
1698                         }
1699                         if ((p = getenv(cp + 1)) != NULL)
1700                                 forward_agent_sock_path = xstrdup(p);
1701                         else
1702                                 options.forward_agent = 0;
1703                         free(cp);
1704                 } else {
1705                         forward_agent_sock_path = cp;
1706                 }
1707         }
1708
1709         /* Expand ~ in known host file names. */
1710         tilde_expand_paths(options.system_hostfiles,
1711             options.num_system_hostfiles);
1712         tilde_expand_paths(options.user_hostfiles, options.num_user_hostfiles);
1713
1714         ssh_signal(SIGCHLD, main_sigchld_handler);
1715
1716         /* Log into the remote system.  Never returns if the login fails. */
1717         ssh_login(ssh, &sensitive_data, host, (struct sockaddr *)&hostaddr,
1718             options.port, pw, timeout_ms, cinfo);
1719
1720         /* We no longer need the private host keys.  Clear them now. */
1721         if (sensitive_data.nkeys != 0) {
1722                 for (i = 0; i < sensitive_data.nkeys; i++) {
1723                         if (sensitive_data.keys[i] != NULL) {
1724                                 /* Destroys contents safely */
1725                                 debug3("clear hostkey %d", i);
1726                                 sshkey_free(sensitive_data.keys[i]);
1727                                 sensitive_data.keys[i] = NULL;
1728                         }
1729                 }
1730                 free(sensitive_data.keys);
1731         }
1732         for (i = 0; i < options.num_identity_files; i++) {
1733                 free(options.identity_files[i]);
1734                 options.identity_files[i] = NULL;
1735                 if (options.identity_keys[i]) {
1736                         sshkey_free(options.identity_keys[i]);
1737                         options.identity_keys[i] = NULL;
1738                 }
1739         }
1740         for (i = 0; i < options.num_certificate_files; i++) {
1741                 free(options.certificate_files[i]);
1742                 options.certificate_files[i] = NULL;
1743         }
1744
1745 #ifdef ENABLE_PKCS11
1746         (void)pkcs11_del_provider(options.pkcs11_provider);
1747 #endif
1748
1749  skip_connect:
1750         exit_status = ssh_session2(ssh, cinfo);
1751         ssh_conn_info_free(cinfo);
1752         ssh_packet_close(ssh);
1753
1754         if (options.control_path != NULL && muxserver_sock != -1)
1755                 unlink(options.control_path);
1756
1757         /* Kill ProxyCommand if it is running. */
1758         ssh_kill_proxy_command();
1759
1760         return exit_status;
1761 }
1762
1763 static void
1764 control_persist_detach(void)
1765 {
1766         pid_t pid;
1767
1768         debug_f("backgrounding master process");
1769
1770         /*
1771          * master (current process) into the background, and make the
1772          * foreground process a client of the backgrounded master.
1773          */
1774         switch ((pid = fork())) {
1775         case -1:
1776                 fatal_f("fork: %s", strerror(errno));
1777         case 0:
1778                 /* Child: master process continues mainloop */
1779                 break;
1780         default:
1781                 /*
1782                  * Parent: set up mux client to connect to backgrounded
1783                  * master.
1784                  */
1785                 debug2_f("background process is %ld", (long)pid);
1786                 options.stdin_null = ostdin_null_flag;
1787                 options.request_tty = orequest_tty;
1788                 tty_flag = otty_flag;
1789                 options.fork_after_authentication = ofork_after_authentication;
1790                 options.session_type = osession_type;
1791                 close(muxserver_sock);
1792                 muxserver_sock = -1;
1793                 options.control_master = SSHCTL_MASTER_NO;
1794                 (void)muxclient(options.control_path);
1795                 /* muxclient() doesn't return on success. */
1796                 fatal("Failed to connect to new control master");
1797         }
1798         if (stdfd_devnull(1, 1, !(log_is_on_stderr() && debug_flag)) == -1)
1799                 error_f("stdfd_devnull failed");
1800         daemon(1, 1);
1801         setproctitle("%s [mux]", options.control_path);
1802 }
1803
1804 /* Do fork() after authentication. Used by "ssh -f" */
1805 static void
1806 fork_postauth(void)
1807 {
1808         if (need_controlpersist_detach)
1809                 control_persist_detach();
1810         debug("forking to background");
1811         options.fork_after_authentication = 0;
1812         if (daemon(1, 1) == -1)
1813                 fatal("daemon() failed: %.200s", strerror(errno));
1814         if (stdfd_devnull(1, 1, !(log_is_on_stderr() && debug_flag)) == -1)
1815                 error_f("stdfd_devnull failed");
1816 }
1817
1818 static void
1819 forwarding_success(void)
1820 {
1821         if (forward_confirms_pending == -1)
1822                 return;
1823         if (--forward_confirms_pending == 0) {
1824                 debug_f("all expected forwarding replies received");
1825                 if (options.fork_after_authentication)
1826                         fork_postauth();
1827         } else {
1828                 debug2_f("%d expected forwarding replies remaining",
1829                     forward_confirms_pending);
1830         }
1831 }
1832
1833 /* Callback for remote forward global requests */
1834 static void
1835 ssh_confirm_remote_forward(struct ssh *ssh, int type, u_int32_t seq, void *ctxt)
1836 {
1837         struct Forward *rfwd = (struct Forward *)ctxt;
1838         u_int port;
1839         int r;
1840
1841         /* XXX verbose() on failure? */
1842         debug("remote forward %s for: listen %s%s%d, connect %s:%d",
1843             type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure",
1844             rfwd->listen_path ? rfwd->listen_path :
1845             rfwd->listen_host ? rfwd->listen_host : "",
1846             (rfwd->listen_path || rfwd->listen_host) ? ":" : "",
1847             rfwd->listen_port, rfwd->connect_path ? rfwd->connect_path :
1848             rfwd->connect_host, rfwd->connect_port);
1849         if (rfwd->listen_path == NULL && rfwd->listen_port == 0) {
1850                 if (type == SSH2_MSG_REQUEST_SUCCESS) {
1851                         if ((r = sshpkt_get_u32(ssh, &port)) != 0)
1852                                 fatal_fr(r, "parse packet");
1853                         if (port > 65535) {
1854                                 error("Invalid allocated port %u for remote "
1855                                     "forward to %s:%d", port,
1856                                     rfwd->connect_host, rfwd->connect_port);
1857                                 /* Ensure failure processing runs below */
1858                                 type = SSH2_MSG_REQUEST_FAILURE;
1859                                 channel_update_permission(ssh,
1860                                     rfwd->handle, -1);
1861                         } else {
1862                                 rfwd->allocated_port = (int)port;
1863                                 logit("Allocated port %u for remote "
1864                                     "forward to %s:%d",
1865                                     rfwd->allocated_port, rfwd->connect_path ?
1866                                     rfwd->connect_path : rfwd->connect_host,
1867                                     rfwd->connect_port);
1868                                 channel_update_permission(ssh,
1869                                     rfwd->handle, rfwd->allocated_port);
1870                         }
1871                 } else {
1872                         channel_update_permission(ssh, rfwd->handle, -1);
1873                 }
1874         }
1875
1876         if (type == SSH2_MSG_REQUEST_FAILURE) {
1877                 if (options.exit_on_forward_failure) {
1878                         if (rfwd->listen_path != NULL)
1879                                 fatal("Error: remote port forwarding failed "
1880                                     "for listen path %s", rfwd->listen_path);
1881                         else
1882                                 fatal("Error: remote port forwarding failed "
1883                                     "for listen port %d", rfwd->listen_port);
1884                 } else {
1885                         if (rfwd->listen_path != NULL)
1886                                 logit("Warning: remote port forwarding failed "
1887                                     "for listen path %s", rfwd->listen_path);
1888                         else
1889                                 logit("Warning: remote port forwarding failed "
1890                                     "for listen port %d", rfwd->listen_port);
1891                 }
1892         }
1893         forwarding_success();
1894 }
1895
1896 static void
1897 client_cleanup_stdio_fwd(struct ssh *ssh, int id, int force, void *arg)
1898 {
1899         debug("stdio forwarding: done");
1900         cleanup_exit(0);
1901 }
1902
1903 static void
1904 ssh_stdio_confirm(struct ssh *ssh, int id, int success, void *arg)
1905 {
1906         if (!success)
1907                 fatal("stdio forwarding failed");
1908 }
1909
1910 static void
1911 ssh_tun_confirm(struct ssh *ssh, int id, int success, void *arg)
1912 {
1913         if (!success) {
1914                 error("Tunnel forwarding failed");
1915                 if (options.exit_on_forward_failure)
1916                         cleanup_exit(255);
1917         }
1918
1919         debug_f("tunnel forward established, id=%d", id);
1920         forwarding_success();
1921 }
1922
1923 static void
1924 ssh_init_stdio_forwarding(struct ssh *ssh)
1925 {
1926         Channel *c;
1927         int in, out;
1928
1929         if (options.stdio_forward_host == NULL)
1930                 return;
1931
1932         debug3_f("%s:%d", options.stdio_forward_host,
1933             options.stdio_forward_port);
1934
1935         if ((in = dup(STDIN_FILENO)) == -1 ||
1936             (out = dup(STDOUT_FILENO)) == -1)
1937                 fatal_f("dup() in/out failed");
1938         if ((c = channel_connect_stdio_fwd(ssh, options.stdio_forward_host,
1939             options.stdio_forward_port, in, out,
1940             CHANNEL_NONBLOCK_STDIO)) == NULL)
1941                 fatal_f("channel_connect_stdio_fwd failed");
1942         channel_register_cleanup(ssh, c->self, client_cleanup_stdio_fwd, 0);
1943         channel_register_open_confirm(ssh, c->self, ssh_stdio_confirm, NULL);
1944 }
1945
1946 static void
1947 ssh_init_forward_permissions(struct ssh *ssh, const char *what, char **opens,
1948     u_int num_opens)
1949 {
1950         u_int i;
1951         int port;
1952         char *addr, *arg, *oarg;
1953         int where = FORWARD_LOCAL;
1954
1955         channel_clear_permission(ssh, FORWARD_ADM, where);
1956         if (num_opens == 0)
1957                 return; /* permit any */
1958
1959         /* handle keywords: "any" / "none" */
1960         if (num_opens == 1 && strcmp(opens[0], "any") == 0)
1961                 return;
1962         if (num_opens == 1 && strcmp(opens[0], "none") == 0) {
1963                 channel_disable_admin(ssh, where);
1964                 return;
1965         }
1966         /* Otherwise treat it as a list of permitted host:port */
1967         for (i = 0; i < num_opens; i++) {
1968                 oarg = arg = xstrdup(opens[i]);
1969                 addr = hpdelim(&arg);
1970                 if (addr == NULL)
1971                         fatal_f("missing host in %s", what);
1972                 addr = cleanhostname(addr);
1973                 if (arg == NULL || ((port = permitopen_port(arg)) < 0))
1974                         fatal_f("bad port number in %s", what);
1975                 /* Send it to channels layer */
1976                 channel_add_permission(ssh, FORWARD_ADM,
1977                     where, addr, port);
1978                 free(oarg);
1979         }
1980 }
1981
1982 static void
1983 ssh_init_forwarding(struct ssh *ssh, char **ifname)
1984 {
1985         int success = 0;
1986         int i;
1987
1988         ssh_init_forward_permissions(ssh, "permitremoteopen",
1989             options.permitted_remote_opens,
1990             options.num_permitted_remote_opens);
1991
1992         if (options.exit_on_forward_failure)
1993                 forward_confirms_pending = 0; /* track pending requests */
1994         /* Initiate local TCP/IP port forwardings. */
1995         for (i = 0; i < options.num_local_forwards; i++) {
1996                 debug("Local connections to %.200s:%d forwarded to remote "
1997                     "address %.200s:%d",
1998                     (options.local_forwards[i].listen_path != NULL) ?
1999                     options.local_forwards[i].listen_path :
2000                     (options.local_forwards[i].listen_host == NULL) ?
2001                     (options.fwd_opts.gateway_ports ? "*" : "LOCALHOST") :
2002                     options.local_forwards[i].listen_host,
2003                     options.local_forwards[i].listen_port,
2004                     (options.local_forwards[i].connect_path != NULL) ?
2005                     options.local_forwards[i].connect_path :
2006                     options.local_forwards[i].connect_host,
2007                     options.local_forwards[i].connect_port);
2008                 success += channel_setup_local_fwd_listener(ssh,
2009                     &options.local_forwards[i], &options.fwd_opts);
2010         }
2011         if (i > 0 && success != i && options.exit_on_forward_failure)
2012                 fatal("Could not request local forwarding.");
2013         if (i > 0 && success == 0)
2014                 error("Could not request local forwarding.");
2015
2016         /* Initiate remote TCP/IP port forwardings. */
2017         for (i = 0; i < options.num_remote_forwards; i++) {
2018                 debug("Remote connections from %.200s:%d forwarded to "
2019                     "local address %.200s:%d",
2020                     (options.remote_forwards[i].listen_path != NULL) ?
2021                     options.remote_forwards[i].listen_path :
2022                     (options.remote_forwards[i].listen_host == NULL) ?
2023                     "LOCALHOST" : options.remote_forwards[i].listen_host,
2024                     options.remote_forwards[i].listen_port,
2025                     (options.remote_forwards[i].connect_path != NULL) ?
2026                     options.remote_forwards[i].connect_path :
2027                     options.remote_forwards[i].connect_host,
2028                     options.remote_forwards[i].connect_port);
2029                 if ((options.remote_forwards[i].handle =
2030                     channel_request_remote_forwarding(ssh,
2031                     &options.remote_forwards[i])) >= 0) {
2032                         client_register_global_confirm(
2033                             ssh_confirm_remote_forward,
2034                             &options.remote_forwards[i]);
2035                         forward_confirms_pending++;
2036                 } else if (options.exit_on_forward_failure)
2037                         fatal("Could not request remote forwarding.");
2038                 else
2039                         logit("Warning: Could not request remote forwarding.");
2040         }
2041
2042         /* Initiate tunnel forwarding. */
2043         if (options.tun_open != SSH_TUNMODE_NO) {
2044                 if ((*ifname = client_request_tun_fwd(ssh,
2045                     options.tun_open, options.tun_local,
2046                     options.tun_remote, ssh_tun_confirm, NULL)) != NULL)
2047                         forward_confirms_pending++;
2048                 else if (options.exit_on_forward_failure)
2049                         fatal("Could not request tunnel forwarding.");
2050                 else
2051                         error("Could not request tunnel forwarding.");
2052         }
2053         if (forward_confirms_pending > 0) {
2054                 debug_f("expecting replies for %d forwards",
2055                     forward_confirms_pending);
2056         }
2057 }
2058
2059 static void
2060 check_agent_present(void)
2061 {
2062         int r;
2063
2064         if (options.forward_agent) {
2065                 /* Clear agent forwarding if we don't have an agent. */
2066                 if ((r = ssh_get_authentication_socket(NULL)) != 0) {
2067                         options.forward_agent = 0;
2068                         if (r != SSH_ERR_AGENT_NOT_PRESENT)
2069                                 debug_r(r, "ssh_get_authentication_socket");
2070                 }
2071         }
2072 }
2073
2074 static void
2075 ssh_session2_setup(struct ssh *ssh, int id, int success, void *arg)
2076 {
2077         extern char **environ;
2078         const char *display, *term;
2079         int r, interactive = tty_flag;
2080         char *proto = NULL, *data = NULL;
2081
2082         if (!success)
2083                 return; /* No need for error message, channels code sends one */
2084
2085         display = getenv("DISPLAY");
2086         if (display == NULL && options.forward_x11)
2087                 debug("X11 forwarding requested but DISPLAY not set");
2088         if (options.forward_x11 && client_x11_get_proto(ssh, display,
2089             options.xauth_location, options.forward_x11_trusted,
2090             options.forward_x11_timeout, &proto, &data) == 0) {
2091                 /* Request forwarding with authentication spoofing. */
2092                 debug("Requesting X11 forwarding with authentication "
2093                     "spoofing.");
2094                 x11_request_forwarding_with_spoofing(ssh, id, display, proto,
2095                     data, 1);
2096                 client_expect_confirm(ssh, id, "X11 forwarding", CONFIRM_WARN);
2097                 /* XXX exit_on_forward_failure */
2098                 interactive = 1;
2099         }
2100
2101         check_agent_present();
2102         if (options.forward_agent) {
2103                 debug("Requesting authentication agent forwarding.");
2104                 channel_request_start(ssh, id, "auth-agent-req@openssh.com", 0);
2105                 if ((r = sshpkt_send(ssh)) != 0)
2106                         fatal_fr(r, "send packet");
2107         }
2108
2109         /* Tell the packet module whether this is an interactive session. */
2110         ssh_packet_set_interactive(ssh, interactive,
2111             options.ip_qos_interactive, options.ip_qos_bulk);
2112
2113         if ((term = lookup_env_in_list("TERM", options.setenv,
2114             options.num_setenv)) == NULL || *term == '\0')
2115                 term = getenv("TERM");
2116         client_session2_setup(ssh, id, tty_flag,
2117             options.session_type == SESSION_TYPE_SUBSYSTEM, term,
2118             NULL, fileno(stdin), command, environ);
2119 }
2120
2121 /* open new channel for a session */
2122 static int
2123 ssh_session2_open(struct ssh *ssh)
2124 {
2125         Channel *c;
2126         int window, packetmax, in, out, err;
2127
2128         if (options.stdin_null) {
2129                 in = open(_PATH_DEVNULL, O_RDONLY);
2130         } else {
2131                 in = dup(STDIN_FILENO);
2132         }
2133         out = dup(STDOUT_FILENO);
2134         err = dup(STDERR_FILENO);
2135
2136         if (in == -1 || out == -1 || err == -1)
2137                 fatal("dup() in/out/err failed");
2138
2139         window = CHAN_SES_WINDOW_DEFAULT;
2140         packetmax = CHAN_SES_PACKET_DEFAULT;
2141         if (tty_flag) {
2142                 window >>= 1;
2143                 packetmax >>= 1;
2144         }
2145         c = channel_new(ssh,
2146             "session", SSH_CHANNEL_OPENING, in, out, err,
2147             window, packetmax, CHAN_EXTENDED_WRITE,
2148             "client-session", CHANNEL_NONBLOCK_STDIO);
2149
2150         debug3_f("channel_new: %d", c->self);
2151
2152         channel_send_open(ssh, c->self);
2153         if (options.session_type != SESSION_TYPE_NONE)
2154                 channel_register_open_confirm(ssh, c->self,
2155                     ssh_session2_setup, NULL);
2156
2157         return c->self;
2158 }
2159
2160 static int
2161 ssh_session2(struct ssh *ssh, const struct ssh_conn_info *cinfo)
2162 {
2163         int r, interactive, id = -1;
2164         char *cp, *tun_fwd_ifname = NULL;
2165
2166         /* XXX should be pre-session */
2167         if (!options.control_persist)
2168                 ssh_init_stdio_forwarding(ssh);
2169
2170         ssh_init_forwarding(ssh, &tun_fwd_ifname);
2171
2172         if (options.local_command != NULL) {
2173                 debug3("expanding LocalCommand: %s", options.local_command);
2174                 cp = options.local_command;
2175                 options.local_command = percent_expand(cp,
2176                     DEFAULT_CLIENT_PERCENT_EXPAND_ARGS(cinfo),
2177                     "T", tun_fwd_ifname == NULL ? "NONE" : tun_fwd_ifname,
2178                     (char *)NULL);
2179                 debug3("expanded LocalCommand: %s", options.local_command);
2180                 free(cp);
2181         }
2182
2183         /* Start listening for multiplex clients */
2184         if (!ssh_packet_get_mux(ssh))
2185                 muxserver_listen(ssh);
2186
2187         /*
2188          * If we are in control persist mode and have a working mux listen
2189          * socket, then prepare to background ourselves and have a foreground
2190          * client attach as a control client.
2191          * NB. we must save copies of the flags that we override for
2192          * the backgrounding, since we defer attachment of the client until
2193          * after the connection is fully established (in particular,
2194          * async rfwd replies have been received for ExitOnForwardFailure).
2195          */
2196         if (options.control_persist && muxserver_sock != -1) {
2197                 ostdin_null_flag = options.stdin_null;
2198                 osession_type = options.session_type;
2199                 orequest_tty = options.request_tty;
2200                 otty_flag = tty_flag;
2201                 ofork_after_authentication = options.fork_after_authentication;
2202                 options.stdin_null = 1;
2203                 options.session_type = SESSION_TYPE_NONE;
2204                 tty_flag = 0;
2205                 if ((osession_type != SESSION_TYPE_NONE ||
2206                     options.stdio_forward_host != NULL))
2207                         need_controlpersist_detach = 1;
2208                 options.fork_after_authentication = 1;
2209         }
2210         /*
2211          * ControlPersist mux listen socket setup failed, attempt the
2212          * stdio forward setup that we skipped earlier.
2213          */
2214         if (options.control_persist && muxserver_sock == -1)
2215                 ssh_init_stdio_forwarding(ssh);
2216
2217         if (options.session_type != SESSION_TYPE_NONE)
2218                 id = ssh_session2_open(ssh);
2219         else {
2220                 interactive = options.control_master == SSHCTL_MASTER_NO;
2221                 /* ControlPersist may have clobbered ControlMaster, so check */
2222                 if (need_controlpersist_detach)
2223                         interactive = otty_flag != 0;
2224                 ssh_packet_set_interactive(ssh, interactive,
2225                     options.ip_qos_interactive, options.ip_qos_bulk);
2226         }
2227
2228         /* If we don't expect to open a new session, then disallow it */
2229         if (options.control_master == SSHCTL_MASTER_NO &&
2230             (ssh->compat & SSH_NEW_OPENSSH)) {
2231                 debug("Requesting no-more-sessions@openssh.com");
2232                 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 ||
2233                     (r = sshpkt_put_cstring(ssh,
2234                     "no-more-sessions@openssh.com")) != 0 ||
2235                     (r = sshpkt_put_u8(ssh, 0)) != 0 ||
2236                     (r = sshpkt_send(ssh)) != 0)
2237                         fatal_fr(r, "send packet");
2238         }
2239
2240         /* Execute a local command */
2241         if (options.local_command != NULL &&
2242             options.permit_local_command)
2243                 ssh_local_cmd(options.local_command);
2244
2245         /*
2246          * stdout is now owned by the session channel; clobber it here
2247          * so future channel closes are propagated to the local fd.
2248          * NB. this can only happen after LocalCommand has completed,
2249          * as it may want to write to stdout.
2250          */
2251         if (!need_controlpersist_detach && stdfd_devnull(0, 1, 0) == -1)
2252                 error_f("stdfd_devnull failed");
2253
2254         /*
2255          * If requested and we are not interested in replies to remote
2256          * forwarding requests, then let ssh continue in the background.
2257          */
2258         if (options.fork_after_authentication) {
2259                 if (options.exit_on_forward_failure &&
2260                     options.num_remote_forwards > 0) {
2261                         debug("deferring postauth fork until remote forward "
2262                             "confirmation received");
2263                 } else
2264                         fork_postauth();
2265         }
2266
2267         return client_loop(ssh, tty_flag, tty_flag ?
2268             options.escape_char : SSH_ESCAPECHAR_NONE, id);
2269 }
2270
2271 /* Loads all IdentityFile and CertificateFile keys */
2272 static void
2273 load_public_identity_files(const struct ssh_conn_info *cinfo)
2274 {
2275         char *filename, *cp;
2276         struct sshkey *public;
2277         int i;
2278         u_int n_ids, n_certs;
2279         char *identity_files[SSH_MAX_IDENTITY_FILES];
2280         struct sshkey *identity_keys[SSH_MAX_IDENTITY_FILES];
2281         int identity_file_userprovided[SSH_MAX_IDENTITY_FILES];
2282         char *certificate_files[SSH_MAX_CERTIFICATE_FILES];
2283         struct sshkey *certificates[SSH_MAX_CERTIFICATE_FILES];
2284         int certificate_file_userprovided[SSH_MAX_CERTIFICATE_FILES];
2285 #ifdef ENABLE_PKCS11
2286         struct sshkey **keys = NULL;
2287         char **comments = NULL;
2288         int nkeys;
2289 #endif /* PKCS11 */
2290
2291         n_ids = n_certs = 0;
2292         memset(identity_files, 0, sizeof(identity_files));
2293         memset(identity_keys, 0, sizeof(identity_keys));
2294         memset(identity_file_userprovided, 0,
2295             sizeof(identity_file_userprovided));
2296         memset(certificate_files, 0, sizeof(certificate_files));
2297         memset(certificates, 0, sizeof(certificates));
2298         memset(certificate_file_userprovided, 0,
2299             sizeof(certificate_file_userprovided));
2300
2301 #ifdef ENABLE_PKCS11
2302         if (options.pkcs11_provider != NULL &&
2303             options.num_identity_files < SSH_MAX_IDENTITY_FILES &&
2304             (pkcs11_init(!options.batch_mode) == 0) &&
2305             (nkeys = pkcs11_add_provider(options.pkcs11_provider, NULL,
2306             &keys, &comments)) > 0) {
2307                 for (i = 0; i < nkeys; i++) {
2308                         if (n_ids >= SSH_MAX_IDENTITY_FILES) {
2309                                 sshkey_free(keys[i]);
2310                                 free(comments[i]);
2311                                 continue;
2312                         }
2313                         identity_keys[n_ids] = keys[i];
2314                         identity_files[n_ids] = comments[i]; /* transferred */
2315                         n_ids++;
2316                 }
2317                 free(keys);
2318                 free(comments);
2319         }
2320 #endif /* ENABLE_PKCS11 */
2321         for (i = 0; i < options.num_identity_files; i++) {
2322                 if (n_ids >= SSH_MAX_IDENTITY_FILES ||
2323                     strcasecmp(options.identity_files[i], "none") == 0) {
2324                         free(options.identity_files[i]);
2325                         options.identity_files[i] = NULL;
2326                         continue;
2327                 }
2328                 cp = tilde_expand_filename(options.identity_files[i], getuid());
2329                 filename = default_client_percent_dollar_expand(cp, cinfo);
2330                 free(cp);
2331                 check_load(sshkey_load_public(filename, &public, NULL),
2332                     &public, filename, "pubkey");
2333                 debug("identity file %s type %d", filename,
2334                     public ? public->type : -1);
2335                 free(options.identity_files[i]);
2336                 identity_files[n_ids] = filename;
2337                 identity_keys[n_ids] = public;
2338                 identity_file_userprovided[n_ids] =
2339                     options.identity_file_userprovided[i];
2340                 if (++n_ids >= SSH_MAX_IDENTITY_FILES)
2341                         continue;
2342
2343                 /*
2344                  * If no certificates have been explicitly listed then try
2345                  * to add the default certificate variant too.
2346                  */
2347                 if (options.num_certificate_files != 0)
2348                         continue;
2349                 xasprintf(&cp, "%s-cert", filename);
2350                 check_load(sshkey_load_public(cp, &public, NULL),
2351                     &public, filename, "pubkey");
2352                 debug("identity file %s type %d", cp,
2353                     public ? public->type : -1);
2354                 if (public == NULL) {
2355                         free(cp);
2356                         continue;
2357                 }
2358                 if (!sshkey_is_cert(public)) {
2359                         debug_f("key %s type %s is not a certificate",
2360                             cp, sshkey_type(public));
2361                         sshkey_free(public);
2362                         free(cp);
2363                         continue;
2364                 }
2365                 /* NB. leave filename pointing to private key */
2366                 identity_files[n_ids] = xstrdup(filename);
2367                 identity_keys[n_ids] = public;
2368                 identity_file_userprovided[n_ids] =
2369                     options.identity_file_userprovided[i];
2370                 n_ids++;
2371         }
2372
2373         if (options.num_certificate_files > SSH_MAX_CERTIFICATE_FILES)
2374                 fatal_f("too many certificates");
2375         for (i = 0; i < options.num_certificate_files; i++) {
2376                 cp = tilde_expand_filename(options.certificate_files[i],
2377                     getuid());
2378                 filename = default_client_percent_dollar_expand(cp, cinfo);
2379                 free(cp);
2380
2381                 check_load(sshkey_load_public(filename, &public, NULL),
2382                     &public, filename, "certificate");
2383                 debug("certificate file %s type %d", filename,
2384                     public ? public->type : -1);
2385                 free(options.certificate_files[i]);
2386                 options.certificate_files[i] = NULL;
2387                 if (public == NULL) {
2388                         free(filename);
2389                         continue;
2390                 }
2391                 if (!sshkey_is_cert(public)) {
2392                         debug_f("key %s type %s is not a certificate",
2393                             filename, sshkey_type(public));
2394                         sshkey_free(public);
2395                         free(filename);
2396                         continue;
2397                 }
2398                 certificate_files[n_certs] = filename;
2399                 certificates[n_certs] = public;
2400                 certificate_file_userprovided[n_certs] =
2401                     options.certificate_file_userprovided[i];
2402                 ++n_certs;
2403         }
2404
2405         options.num_identity_files = n_ids;
2406         memcpy(options.identity_files, identity_files, sizeof(identity_files));
2407         memcpy(options.identity_keys, identity_keys, sizeof(identity_keys));
2408         memcpy(options.identity_file_userprovided,
2409             identity_file_userprovided, sizeof(identity_file_userprovided));
2410
2411         options.num_certificate_files = n_certs;
2412         memcpy(options.certificate_files,
2413             certificate_files, sizeof(certificate_files));
2414         memcpy(options.certificates, certificates, sizeof(certificates));
2415         memcpy(options.certificate_file_userprovided,
2416             certificate_file_userprovided,
2417             sizeof(certificate_file_userprovided));
2418 }
2419
2420 static void
2421 main_sigchld_handler(int sig)
2422 {
2423         int save_errno = errno;
2424         pid_t pid;
2425         int status;
2426
2427         while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
2428             (pid == -1 && errno == EINTR))
2429                 ;
2430         errno = save_errno;
2431 }