ssh.c

   1 /* $OpenBSD: ssh.c,v 1.475 2018/02/23 15:58:38 markus 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 SSL 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 <unistd.h>
  69 #include <limits.h>
  70 #include <locale.h>
  71
  72 #include <netinet/in.h>
  73 #include <arpa/inet.h>
  74
  75 #ifdef WITH_OPENSSL
  76 #include <openssl/evp.h>
  77 #include <openssl/err.h>
  78 #endif
  79 #include "openbsd-compat/openssl-compat.h"
  80 #include "openbsd-compat/sys-queue.h"
  81
  82 #include "xmalloc.h"
  83 #include "ssh.h"
  84 #include "ssh2.h"
  85 #include "canohost.h"
  86 #include "compat.h"
  87 #include "cipher.h"
  88 #include "digest.h"
  89 #include "packet.h"
  90 #include "buffer.h"
  91 #include "channels.h"
  92 #include "key.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 "uidswap.h"
 108 #include "version.h"
 109 #include "ssherr.h"
 110 #include "myproposal.h"
 111 #include "utf8.h"
 112
 113 #ifdef ENABLE_PKCS11
 114 #include "ssh-pkcs11.h"
 115 #endif
 116
 117 extern char *__progname;
 118
 119 /* Saves a copy of argv for setproctitle emulation */
 120 #ifndef HAVE_SETPROCTITLE
 121 static char **saved_av;
 122 #endif
 123
 124 /* Flag indicating whether debug mode is on.  May be set on the command line. */
 125 int debug_flag = 0;
 126
 127 /* Flag indicating whether a tty should be requested */
 128 int tty_flag = 0;
 129
 130 /* don't exec a shell */
 131 int no_shell_flag = 0;
 132
 133 /*
 134  * Flag indicating that nothing should be read from stdin.  This can be set
 135  * on the command line.
 136  */
 137 int stdin_null_flag = 0;
 138
 139 /*
 140  * Flag indicating that the current process should be backgrounded and
 141  * a new slave launched in the foreground for ControlPersist.
 142  */
 143 int need_controlpersist_detach = 0;
 144
 145 /* Copies of flags for ControlPersist foreground slave */
 146 int ostdin_null_flag, ono_shell_flag, otty_flag, orequest_tty;
 147
 148 /*
 149  * Flag indicating that ssh should fork after authentication.  This is useful
 150  * so that the passphrase can be entered manually, and then ssh goes to the
 151  * background.
 152  */
 153 int fork_after_authentication_flag = 0;
 154
 155 /*
 156  * General data structure for command line options and options configurable
 157  * in configuration files.  See readconf.h.
 158  */
 159 Options options;
 160
 161 /* optional user configfile */
 162 char *config = NULL;
 163
 164 /*
 165  * Name of the host we are connecting to.  This is the name given on the
 166  * command line, or the HostName specified for the user-supplied name in a
 167  * configuration file.
 168  */
 169 char *host;
 170
 171 /* Various strings used to to percent_expand() arguments */
 172 static char thishost[NI_MAXHOST], shorthost[NI_MAXHOST], portstr[NI_MAXSERV];
 173 static char uidstr[32], *host_arg, *conn_hash_hex;
 174
 175 /* socket address the host resolves to */
 176 struct sockaddr_storage hostaddr;
 177
 178 /* Private host keys. */
 179 Sensitive sensitive_data;
 180
 181 /* Original real UID. */
 182 uid_t original_real_uid;
 183 uid_t original_effective_uid;
 184
 185 /* command to be executed */
 186 Buffer command;
 187
 188 /* Should we execute a command or invoke a subsystem? */
 189 int subsystem_flag = 0;
 190
 191 /* # of replies received for global requests */
 192 static int remote_forward_confirms_received = 0;
 193
 194 /* mux.c */
 195 extern int muxserver_sock;
 196 extern u_int muxclient_command;
 197
 198 /* Prints a help message to the user.  This function never returns. */
 199
 200 static void
 201 usage(void)
 202 {
 203         fprintf(stderr,
 204 "usage: ssh [-46AaCfGgKkMNnqsTtVvXxYy] [-B bind_interface]\n"
 205 "           [-b bind_address] [-c cipher_spec] [-D [bind_address:]port]\n"
 206 "           [-E log_file] [-e escape_char] [-F configfile] [-I pkcs11]\n"
 207 "           [-i identity_file] [-J [user@]host[:port]] [-L address]\n"
 208 "           [-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port]\n"
 209 "           [-Q query_option] [-R address] [-S ctl_path] [-W host:port]\n"
 210 "           [-w local_tun[:remote_tun]] destination [command]\n"
 211         );
 212         exit(255);
 213 }
 214
 215 static int ssh_session2(struct ssh *, struct passwd *);
 216 static void load_public_identity_files(struct passwd *);
 217 static void main_sigchld_handler(int);
 218
 219 /* ~/ expand a list of paths. NB. assumes path[n] is heap-allocated. */
 220 static void
 221 tilde_expand_paths(char **paths, u_int num_paths)
 222 {
 223         u_int i;
 224         char *cp;
 225
 226         for (i = 0; i < num_paths; i++) {
 227                 cp = tilde_expand_filename(paths[i], original_real_uid);
 228                 free(paths[i]);
 229                 paths[i] = cp;
 230         }
 231 }
 232
 233 /*
 234  * Attempt to resolve a host name / port to a set of addresses and
 235  * optionally return any CNAMEs encountered along the way.
 236  * Returns NULL on failure.
 237  * NB. this function must operate with a options having undefined members.
 238  */
 239 static struct addrinfo *
 240 resolve_host(const char *name, int port, int logerr, char *cname, size_t clen)
 241 {
 242         char strport[NI_MAXSERV];
 243         struct addrinfo hints, *res;
 244         int gaierr, loglevel = SYSLOG_LEVEL_DEBUG1;
 245
 246         if (port <= 0)
 247                 port = default_ssh_port();
 248
 249         snprintf(strport, sizeof strport, "%d", port);
 250         memset(&hints, 0, sizeof(hints));
 251         hints.ai_family = options.address_family == -1 ?
 252             AF_UNSPEC : options.address_family;
 253         hints.ai_socktype = SOCK_STREAM;
 254         if (cname != NULL)
 255                 hints.ai_flags = AI_CANONNAME;
 256         if ((gaierr = getaddrinfo(name, strport, &hints, &res)) != 0) {
 257                 if (logerr || (gaierr != EAI_NONAME && gaierr != EAI_NODATA))
 258                         loglevel = SYSLOG_LEVEL_ERROR;
 259                 do_log2(loglevel, "%s: Could not resolve hostname %.100s: %s",
 260                     __progname, name, ssh_gai_strerror(gaierr));
 261                 return NULL;
 262         }
 263         if (cname != NULL && res->ai_canonname != NULL) {
 264                 if (strlcpy(cname, res->ai_canonname, clen) >= clen) {
 265                         error("%s: host \"%s\" cname \"%s\" too long (max %lu)",
 266                             __func__, name,  res->ai_canonname, (u_long)clen);
 267                         if (clen > 0)
 268                                 *cname = '\0';
 269                 }
 270         }
 271         return res;
 272 }
 273
 274 /* Returns non-zero if name can only be an address and not a hostname */
 275 static int
 276 is_addr_fast(const char *name)
 277 {
 278         return (strchr(name, '%') != NULL || strchr(name, ':') != NULL ||
 279             strspn(name, "0123456789.") == strlen(name));
 280 }
 281
 282 /* Returns non-zero if name represents a valid, single address */
 283 static int
 284 is_addr(const char *name)
 285 {
 286         char strport[NI_MAXSERV];
 287         struct addrinfo hints, *res;
 288
 289         if (is_addr_fast(name))
 290                 return 1;
 291
 292         snprintf(strport, sizeof strport, "%u", default_ssh_port());
 293         memset(&hints, 0, sizeof(hints));
 294         hints.ai_family = options.address_family == -1 ?
 295             AF_UNSPEC : options.address_family;
 296         hints.ai_socktype = SOCK_STREAM;
 297         hints.ai_flags = AI_NUMERICHOST|AI_NUMERICSERV;
 298         if (getaddrinfo(name, strport, &hints, &res) != 0)
 299                 return 0;
 300         if (res == NULL || res->ai_next != NULL) {
 301                 freeaddrinfo(res);
 302                 return 0;
 303         }
 304         freeaddrinfo(res);
 305         return 1;
 306 }
 307
 308 /*
 309  * Attempt to resolve a numeric host address / port to a single address.
 310  * Returns a canonical address string.
 311  * Returns NULL on failure.
 312  * NB. this function must operate with a options having undefined members.
 313  */
 314 static struct addrinfo *
 315 resolve_addr(const char *name, int port, char *caddr, size_t clen)
 316 {
 317         char addr[NI_MAXHOST], strport[NI_MAXSERV];
 318         struct addrinfo hints, *res;
 319         int gaierr;
 320
 321         if (port <= 0)
 322                 port = default_ssh_port();
 323         snprintf(strport, sizeof strport, "%u", port);
 324         memset(&hints, 0, sizeof(hints));
 325         hints.ai_family = options.address_family == -1 ?
 326             AF_UNSPEC : options.address_family;
 327         hints.ai_socktype = SOCK_STREAM;
 328         hints.ai_flags = AI_NUMERICHOST|AI_NUMERICSERV;
 329         if ((gaierr = getaddrinfo(name, strport, &hints, &res)) != 0) {
 330                 debug2("%s: could not resolve name %.100s as address: %s",
 331                     __func__, name, ssh_gai_strerror(gaierr));
 332                 return NULL;
 333         }
 334         if (res == NULL) {
 335                 debug("%s: getaddrinfo %.100s returned no addresses",
 336                  __func__, name);
 337                 return NULL;
 338         }
 339         if (res->ai_next != NULL) {
 340                 debug("%s: getaddrinfo %.100s returned multiple addresses",
 341                     __func__, name);
 342                 goto fail;
 343         }
 344         if ((gaierr = getnameinfo(res->ai_addr, res->ai_addrlen,
 345             addr, sizeof(addr), NULL, 0, NI_NUMERICHOST)) != 0) {
 346                 debug("%s: Could not format address for name %.100s: %s",
 347                     __func__, name, ssh_gai_strerror(gaierr));
 348                 goto fail;
 349         }
 350         if (strlcpy(caddr, addr, clen) >= clen) {
 351                 error("%s: host \"%s\" addr \"%s\" too long (max %lu)",
 352                     __func__, name,  addr, (u_long)clen);
 353                 if (clen > 0)
 354                         *caddr = '\0';
 355  fail:
 356                 freeaddrinfo(res);
 357                 return NULL;
 358         }
 359         return res;
 360 }
 361
 362 /*
 363  * Check whether the cname is a permitted replacement for the hostname
 364  * and perform the replacement if it is.
 365  * NB. this function must operate with a options having undefined members.
 366  */
 367 static int
 368 check_follow_cname(int direct, char **namep, const char *cname)
 369 {
 370         int i;
 371         struct allowed_cname *rule;
 372
 373         if (*cname == '\0' || options.num_permitted_cnames == 0 ||
 374             strcmp(*namep, cname) == 0)
 375                 return 0;
 376         if (options.canonicalize_hostname == SSH_CANONICALISE_NO)
 377                 return 0;
 378         /*
 379          * Don't attempt to canonicalize names that will be interpreted by
 380          * a proxy or jump host unless the user specifically requests so.
 381          */
 382         if (!direct &&
 383             options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS)
 384                 return 0;
 385         debug3("%s: check \"%s\" CNAME \"%s\"", __func__, *namep, cname);
 386         for (i = 0; i < options.num_permitted_cnames; i++) {
 387                 rule = options.permitted_cnames + i;
 388                 if (match_pattern_list(*namep, rule->source_list, 1) != 1 ||
 389                     match_pattern_list(cname, rule->target_list, 1) != 1)
 390                         continue;
 391                 verbose("Canonicalized DNS aliased hostname "
 392                     "\"%s\" => \"%s\"", *namep, cname);
 393                 free(*namep);
 394                 *namep = xstrdup(cname);
 395                 return 1;
 396         }
 397         return 0;
 398 }
 399
 400 /*
 401  * Attempt to resolve the supplied hostname after applying the user's
 402  * canonicalization rules. Returns the address list for the host or NULL
 403  * if no name was found after canonicalization.
 404  * NB. this function must operate with a options having undefined members.
 405  */
 406 static struct addrinfo *
 407 resolve_canonicalize(char **hostp, int port)
 408 {
 409         int i, direct, ndots;
 410         char *cp, *fullhost, newname[NI_MAXHOST];
 411         struct addrinfo *addrs;
 412
 413         /*
 414          * Attempt to canonicalise addresses, regardless of
 415          * whether hostname canonicalisation was requested
 416          */
 417         if ((addrs = resolve_addr(*hostp, port,
 418             newname, sizeof(newname))) != NULL) {
 419                 debug2("%s: hostname %.100s is address", __func__, *hostp);
 420                 if (strcasecmp(*hostp, newname) != 0) {
 421                         debug2("%s: canonicalised address \"%s\" => \"%s\"",
 422                             __func__, *hostp, newname);
 423                         free(*hostp);
 424                         *hostp = xstrdup(newname);
 425                 }
 426                 return addrs;
 427         }
 428
 429         /*
 430          * If this looks like an address but didn't parse as one, it might
 431          * be an address with an invalid interface scope. Skip further
 432          * attempts at canonicalisation.
 433          */
 434         if (is_addr_fast(*hostp)) {
 435                 debug("%s: hostname %.100s is an unrecognised address",
 436                     __func__, *hostp);
 437                 return NULL;
 438         }
 439
 440         if (options.canonicalize_hostname == SSH_CANONICALISE_NO)
 441                 return NULL;
 442
 443         /*
 444          * Don't attempt to canonicalize names that will be interpreted by
 445          * a proxy unless the user specifically requests so.
 446          */
 447         direct = option_clear_or_none(options.proxy_command) &&
 448             options.jump_host == NULL;
 449         if (!direct &&
 450             options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS)
 451                 return NULL;
 452
 453         /* If domain name is anchored, then resolve it now */
 454         if ((*hostp)[strlen(*hostp) - 1] == '.') {
 455                 debug3("%s: name is fully qualified", __func__);
 456                 fullhost = xstrdup(*hostp);
 457                 if ((addrs = resolve_host(fullhost, port, 0,
 458                     newname, sizeof(newname))) != NULL)
 459                         goto found;
 460                 free(fullhost);
 461                 goto notfound;
 462         }
 463
 464         /* Don't apply canonicalization to sufficiently-qualified hostnames */
 465         ndots = 0;
 466         for (cp = *hostp; *cp != '\0'; cp++) {
 467                 if (*cp == '.')
 468                         ndots++;
 469         }
 470         if (ndots > options.canonicalize_max_dots) {
 471                 debug3("%s: not canonicalizing hostname \"%s\" (max dots %d)",
 472                     __func__, *hostp, options.canonicalize_max_dots);
 473                 return NULL;
 474         }
 475         /* Attempt each supplied suffix */
 476         for (i = 0; i < options.num_canonical_domains; i++) {
 477                 *newname = '\0';
 478                 xasprintf(&fullhost, "%s.%s.", *hostp,
 479                     options.canonical_domains[i]);
 480                 debug3("%s: attempting \"%s\" => \"%s\"", __func__,
 481                     *hostp, fullhost);
 482                 if ((addrs = resolve_host(fullhost, port, 0,
 483                     newname, sizeof(newname))) == NULL) {
 484                         free(fullhost);
 485                         continue;
 486                 }
 487  found:
 488                 /* Remove trailing '.' */
 489                 fullhost[strlen(fullhost) - 1] = '\0';
 490                 /* Follow CNAME if requested */
 491                 if (!check_follow_cname(direct, &fullhost, newname)) {
 492                         debug("Canonicalized hostname \"%s\" => \"%s\"",
 493                             *hostp, fullhost);
 494                 }
 495                 free(*hostp);
 496                 *hostp = fullhost;
 497                 return addrs;
 498         }
 499  notfound:
 500         if (!options.canonicalize_fallback_local)
 501                 fatal("%s: Could not resolve host \"%s\"", __progname, *hostp);
 502         debug2("%s: host %s not found in any suffix", __func__, *hostp);
 503         return NULL;
 504 }
 505
 506 /*
 507  * Read per-user configuration file.  Ignore the system wide config
 508  * file if the user specifies a config file on the command line.
 509  */
 510 static void
 511 process_config_files(const char *host_name, struct passwd *pw, int post_canon)
 512 {
 513         char buf[PATH_MAX];
 514         int r;
 515
 516         if (config != NULL) {
 517                 if (strcasecmp(config, "none") != 0 &&
 518                     !read_config_file(config, pw, host, host_name, &options,
 519                     SSHCONF_USERCONF | (post_canon ? SSHCONF_POSTCANON : 0)))
 520                         fatal("Can't open user config file %.100s: "
 521                             "%.100s", config, strerror(errno));
 522         } else {
 523                 r = snprintf(buf, sizeof buf, "%s/%s", pw->pw_dir,
 524                     _PATH_SSH_USER_CONFFILE);
 525                 if (r > 0 && (size_t)r < sizeof(buf))
 526                         (void)read_config_file(buf, pw, host, host_name,
 527                             &options, SSHCONF_CHECKPERM | SSHCONF_USERCONF |
 528                             (post_canon ? SSHCONF_POSTCANON : 0));
 529
 530                 /* Read systemwide configuration file after user config. */
 531                 (void)read_config_file(_PATH_HOST_CONFIG_FILE, pw,
 532                     host, host_name, &options,
 533                     post_canon ? SSHCONF_POSTCANON : 0);
 534         }
 535 }
 536
 537 /* Rewrite the port number in an addrinfo list of addresses */
 538 static void
 539 set_addrinfo_port(struct addrinfo *addrs, int port)
 540 {
 541         struct addrinfo *addr;
 542
 543         for (addr = addrs; addr != NULL; addr = addr->ai_next) {
 544                 switch (addr->ai_family) {
 545                 case AF_INET:
 546                         ((struct sockaddr_in *)addr->ai_addr)->
 547                             sin_port = htons(port);
 548                         break;
 549                 case AF_INET6:
 550                         ((struct sockaddr_in6 *)addr->ai_addr)->
 551                             sin6_port = htons(port);
 552                         break;
 553                 }
 554         }
 555 }
 556
 557 /*
 558  * Main program for the ssh client.
 559  */
 560 int
 561 main(int ac, char **av)
 562 {
 563         struct ssh *ssh = NULL;
 564         int i, r, opt, exit_status, use_syslog, direct, timeout_ms;
 565         int was_addr, config_test = 0, opt_terminated = 0;
 566         char *p, *cp, *line, *argv0, buf[PATH_MAX], *logfile;
 567         char cname[NI_MAXHOST];
 568         struct stat st;
 569         struct passwd *pw;
 570         extern int optind, optreset;
 571         extern char *optarg;
 572         struct Forward fwd;
 573         struct addrinfo *addrs = NULL;
 574         struct ssh_digest_ctx *md;
 575         u_char conn_hash[SSH_DIGEST_MAX_LENGTH];
 576
 577         ssh_malloc_init();      /* must be called before any mallocs */
 578         /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
 579         sanitise_stdfd();
 580
 581         __progname = ssh_get_progname(av[0]);
 582
 583 #ifndef HAVE_SETPROCTITLE
 584         /* Prepare for later setproctitle emulation */
 585         /* Save argv so it isn't clobbered by setproctitle() emulation */
 586         saved_av = xcalloc(ac + 1, sizeof(*saved_av));
 587         for (i = 0; i < ac; i++)
 588                 saved_av[i] = xstrdup(av[i]);
 589         saved_av[i] = NULL;
 590         compat_init_setproctitle(ac, av);
 591         av = saved_av;
 592 #endif
 593
 594         /*
 595          * Discard other fds that are hanging around. These can cause problem
 596          * with backgrounded ssh processes started by ControlPersist.
 597          */
 598         closefrom(STDERR_FILENO + 1);
 599
 600         /*
 601          * Save the original real uid.  It will be needed later (uid-swapping
 602          * may clobber the real uid).
 603          */
 604         original_real_uid = getuid();
 605         original_effective_uid = geteuid();
 606
 607         /*
 608          * Use uid-swapping to give up root privileges for the duration of
 609          * option processing.  We will re-instantiate the rights when we are
 610          * ready to create the privileged port, and will permanently drop
 611          * them when the port has been created (actually, when the connection
 612          * has been made, as we may need to create the port several times).
 613          */
 614         PRIV_END;
 615
 616 #ifdef HAVE_SETRLIMIT
 617         /* If we are installed setuid root be careful to not drop core. */
 618         if (original_real_uid != original_effective_uid) {
 619                 struct rlimit rlim;
 620                 rlim.rlim_cur = rlim.rlim_max = 0;
 621                 if (setrlimit(RLIMIT_CORE, &rlim) < 0)
 622                         fatal("setrlimit failed: %.100s", strerror(errno));
 623         }
 624 #endif
 625         /* Get user data. */
 626         pw = getpwuid(original_real_uid);
 627         if (!pw) {
 628                 logit("No user exists for uid %lu", (u_long)original_real_uid);
 629                 exit(255);
 630         }
 631         /* Take a copy of the returned structure. */
 632         pw = pwcopy(pw);
 633
 634         /*
 635          * Set our umask to something reasonable, as some files are created
 636          * with the default umask.  This will make them world-readable but
 637          * writable only by the owner, which is ok for all files for which we
 638          * don't set the modes explicitly.
 639          */
 640         umask(022);
 641
 642         msetlocale();
 643
 644         /*
 645          * Initialize option structure to indicate that no values have been
 646          * set.
 647          */
 648         initialize_options(&options);
 649
 650         /*
 651          * Prepare main ssh transport/connection structures
 652          */
 653         if ((ssh = ssh_alloc_session_state()) == NULL)
 654                 fatal("Couldn't allocate session state");
 655         channel_init_channels(ssh);
 656         active_state = ssh; /* XXX legacy API compat */
 657
 658         /* Parse command-line arguments. */
 659         host = NULL;
 660         use_syslog = 0;
 661         logfile = NULL;
 662         argv0 = av[0];
 663
 664  again:
 665         while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx"
 666             "AB:CD:E:F:GI:J:KL:MNO:PQ:R:S:TVw:W:XYy")) != -1) {
 667                 switch (opt) {
 668                 case '1':
 669                         fatal("SSH protocol v.1 is no longer supported");
 670                         break;
 671                 case '2':
 672                         /* Ignored */
 673                         break;
 674                 case '4':
 675                         options.address_family = AF_INET;
 676                         break;
 677                 case '6':
 678                         options.address_family = AF_INET6;
 679                         break;
 680                 case 'n':
 681                         stdin_null_flag = 1;
 682                         break;
 683                 case 'f':
 684                         fork_after_authentication_flag = 1;
 685                         stdin_null_flag = 1;
 686                         break;
 687                 case 'x':
 688                         options.forward_x11 = 0;
 689                         break;
 690                 case 'X':
 691                         options.forward_x11 = 1;
 692                         break;
 693                 case 'y':
 694                         use_syslog = 1;
 695                         break;
 696                 case 'E':
 697                         logfile = optarg;
 698                         break;
 699                 case 'G':
 700                         config_test = 1;
 701                         break;
 702                 case 'Y':
 703                         options.forward_x11 = 1;
 704                         options.forward_x11_trusted = 1;
 705                         break;
 706                 case 'g':
 707                         options.fwd_opts.gateway_ports = 1;
 708                         break;
 709                 case 'O':
 710                         if (options.stdio_forward_host != NULL)
 711                                 fatal("Cannot specify multiplexing "
 712                                     "command with -W");
 713                         else if (muxclient_command != 0)
 714                                 fatal("Multiplexing command already specified");
 715                         if (strcmp(optarg, "check") == 0)
 716                                 muxclient_command = SSHMUX_COMMAND_ALIVE_CHECK;
 717                         else if (strcmp(optarg, "forward") == 0)
 718                                 muxclient_command = SSHMUX_COMMAND_FORWARD;
 719                         else if (strcmp(optarg, "exit") == 0)
 720                                 muxclient_command = SSHMUX_COMMAND_TERMINATE;
 721                         else if (strcmp(optarg, "stop") == 0)
 722                                 muxclient_command = SSHMUX_COMMAND_STOP;
 723                         else if (strcmp(optarg, "cancel") == 0)
 724                                 muxclient_command = SSHMUX_COMMAND_CANCEL_FWD;
 725                         else if (strcmp(optarg, "proxy") == 0)
 726                                 muxclient_command = SSHMUX_COMMAND_PROXY;
 727                         else
 728                                 fatal("Invalid multiplex command.");
 729                         break;
 730                 case 'P':       /* deprecated */
 731                         options.use_privileged_port = 0;
 732                         break;
 733                 case 'Q':
 734                         cp = NULL;
 735                         if (strcmp(optarg, "cipher") == 0)
 736                                 cp = cipher_alg_list('\n', 0);
 737                         else if (strcmp(optarg, "cipher-auth") == 0)
 738                                 cp = cipher_alg_list('\n', 1);
 739                         else if (strcmp(optarg, "mac") == 0)
 740                                 cp = mac_alg_list('\n');
 741                         else if (strcmp(optarg, "kex") == 0)
 742                                 cp = kex_alg_list('\n');
 743                         else if (strcmp(optarg, "key") == 0)
 744                                 cp = sshkey_alg_list(0, 0, 0, '\n');
 745                         else if (strcmp(optarg, "key-cert") == 0)
 746                                 cp = sshkey_alg_list(1, 0, 0, '\n');
 747                         else if (strcmp(optarg, "key-plain") == 0)
 748                                 cp = sshkey_alg_list(0, 1, 0, '\n');
 749                         else if (strcmp(optarg, "protocol-version") == 0) {
 750                                 cp = xstrdup("2");
 751                         }
 752                         if (cp == NULL)
 753                                 fatal("Unsupported query \"%s\"", optarg);
 754                         printf("%s\n", cp);
 755                         free(cp);
 756                         exit(0);
 757                         break;
 758                 case 'a':
 759                         options.forward_agent = 0;
 760                         break;
 761                 case 'A':
 762                         options.forward_agent = 1;
 763                         break;
 764                 case 'k':
 765                         options.gss_deleg_creds = 0;
 766                         break;
 767                 case 'K':
 768                         options.gss_authentication = 1;
 769                         options.gss_deleg_creds = 1;
 770                         break;
 771                 case 'i':
 772                         p = tilde_expand_filename(optarg, original_real_uid);
 773                         if (stat(p, &st) < 0)
 774                                 fprintf(stderr, "Warning: Identity file %s "
 775                                     "not accessible: %s.\n", p,
 776                                     strerror(errno));
 777                         else
 778                                 add_identity_file(&options, NULL, p, 1);
 779                         free(p);
 780                         break;
 781                 case 'I':
 782 #ifdef ENABLE_PKCS11
 783                         free(options.pkcs11_provider);
 784                         options.pkcs11_provider = xstrdup(optarg);
 785 #else
 786                         fprintf(stderr, "no support for PKCS#11.\n");
 787 #endif
 788                         break;
 789                 case 'J':
 790                         if (options.jump_host != NULL)
 791                                 fatal("Only a single -J option permitted");
 792                         if (options.proxy_command != NULL)
 793                                 fatal("Cannot specify -J with ProxyCommand");
 794                         if (parse_jump(optarg, &options, 1) == -1)
 795                                 fatal("Invalid -J argument");
 796                         options.proxy_command = xstrdup("none");
 797                         break;
 798                 case 't':
 799                         if (options.request_tty == REQUEST_TTY_YES)
 800                                 options.request_tty = REQUEST_TTY_FORCE;
 801                         else
 802                                 options.request_tty = REQUEST_TTY_YES;
 803                         break;
 804                 case 'v':
 805                         if (debug_flag == 0) {
 806                                 debug_flag = 1;
 807                                 options.log_level = SYSLOG_LEVEL_DEBUG1;
 808                         } else {
 809                                 if (options.log_level < SYSLOG_LEVEL_DEBUG3) {
 810                                         debug_flag++;
 811                                         options.log_level++;
 812                                 }
 813                         }
 814                         break;
 815                 case 'V':
 816                         fprintf(stderr, "%s, %s\n",
 817                             SSH_RELEASE,
 818 #ifdef WITH_OPENSSL
 819                             SSLeay_version(SSLEAY_VERSION)
 820 #else
 821                             "without OpenSSL"
 822 #endif
 823                         );
 824                         if (opt == 'V')
 825                                 exit(0);
 826                         break;
 827                 case 'w':
 828                         if (options.tun_open == -1)
 829                                 options.tun_open = SSH_TUNMODE_DEFAULT;
 830                         options.tun_local = a2tun(optarg, &options.tun_remote);
 831                         if (options.tun_local == SSH_TUNID_ERR) {
 832                                 fprintf(stderr,
 833                                     "Bad tun device '%s'\n", optarg);
 834                                 exit(255);
 835                         }
 836                         break;
 837                 case 'W':
 838                         if (options.stdio_forward_host != NULL)
 839                                 fatal("stdio forward already specified");
 840                         if (muxclient_command != 0)
 841                                 fatal("Cannot specify stdio forward with -O");
 842                         if (parse_forward(&fwd, optarg, 1, 0)) {
 843                                 options.stdio_forward_host = fwd.listen_host;
 844                                 options.stdio_forward_port = fwd.listen_port;
 845                                 free(fwd.connect_host);
 846                         } else {
 847                                 fprintf(stderr,
 848                                     "Bad stdio forwarding specification '%s'\n",
 849                                     optarg);
 850                                 exit(255);
 851                         }
 852                         options.request_tty = REQUEST_TTY_NO;
 853                         no_shell_flag = 1;
 854                         break;
 855                 case 'q':
 856                         options.log_level = SYSLOG_LEVEL_QUIET;
 857                         break;
 858                 case 'e':
 859                         if (optarg[0] == '^' && optarg[2] == 0 &&
 860                             (u_char) optarg[1] >= 64 &&
 861                             (u_char) optarg[1] < 128)
 862                                 options.escape_char = (u_char) optarg[1] & 31;
 863                         else if (strlen(optarg) == 1)
 864                                 options.escape_char = (u_char) optarg[0];
 865                         else if (strcmp(optarg, "none") == 0)
 866                                 options.escape_char = SSH_ESCAPECHAR_NONE;
 867                         else {
 868                                 fprintf(stderr, "Bad escape character '%s'.\n",
 869                                     optarg);
 870                                 exit(255);
 871                         }
 872                         break;
 873                 case 'c':
 874                         if (!ciphers_valid(*optarg == '+' ?
 875                             optarg + 1 : optarg)) {
 876                                 fprintf(stderr, "Unknown cipher type '%s'\n",
 877                                     optarg);
 878                                 exit(255);
 879                         }
 880                         free(options.ciphers);
 881                         options.ciphers = xstrdup(optarg);
 882                         break;
 883                 case 'm':
 884                         if (mac_valid(optarg)) {
 885                                 free(options.macs);
 886                                 options.macs = xstrdup(optarg);
 887                         } else {
 888                                 fprintf(stderr, "Unknown mac type '%s'\n",
 889                                     optarg);
 890                                 exit(255);
 891                         }
 892                         break;
 893                 case 'M':
 894                         if (options.control_master == SSHCTL_MASTER_YES)
 895                                 options.control_master = SSHCTL_MASTER_ASK;
 896                         else
 897                                 options.control_master = SSHCTL_MASTER_YES;
 898                         break;
 899                 case 'p':
 900                         if (options.port == -1) {
 901                                 options.port = a2port(optarg);
 902                                 if (options.port <= 0) {
 903                                         fprintf(stderr, "Bad port '%s'\n",
 904                                             optarg);
 905                                         exit(255);
 906                                 }
 907                         }
 908                         break;
 909                 case 'l':
 910                         if (options.user == NULL)
 911                                 options.user = optarg;
 912                         break;
 913
 914                 case 'L':
 915                         if (parse_forward(&fwd, optarg, 0, 0))
 916                                 add_local_forward(&options, &fwd);
 917                         else {
 918                                 fprintf(stderr,
 919                                     "Bad local forwarding specification '%s'\n",
 920                                     optarg);
 921                                 exit(255);
 922                         }
 923                         break;
 924
 925                 case 'R':
 926                         if (parse_forward(&fwd, optarg, 0, 1) ||
 927                             parse_forward(&fwd, optarg, 1, 1)) {
 928                                 add_remote_forward(&options, &fwd);
 929                         } else {
 930                                 fprintf(stderr,
 931                                     "Bad remote forwarding specification "
 932                                     "'%s'\n", optarg);
 933                                 exit(255);
 934                         }
 935                         break;
 936
 937                 case 'D':
 938                         if (parse_forward(&fwd, optarg, 1, 0)) {
 939                                 add_local_forward(&options, &fwd);
 940                         } else {
 941                                 fprintf(stderr,
 942                                     "Bad dynamic forwarding specification "
 943                                     "'%s'\n", optarg);
 944                                 exit(255);
 945                         }
 946                         break;
 947
 948                 case 'C':
 949                         options.compression = 1;
 950                         break;
 951                 case 'N':
 952                         no_shell_flag = 1;
 953                         options.request_tty = REQUEST_TTY_NO;
 954                         break;
 955                 case 'T':
 956                         options.request_tty = REQUEST_TTY_NO;
 957                         break;
 958                 case 'o':
 959                         line = xstrdup(optarg);
 960                         if (process_config_line(&options, pw,
 961                             host ? host : "", host ? host : "", line,
 962                             "command-line", 0, NULL, SSHCONF_USERCONF) != 0)
 963                                 exit(255);
 964                         free(line);
 965                         break;
 966                 case 's':
 967                         subsystem_flag = 1;
 968                         break;
 969                 case 'S':
 970                         free(options.control_path);
 971                         options.control_path = xstrdup(optarg);
 972                         break;
 973                 case 'b':
 974                         options.bind_address = optarg;
 975                         break;
 976                 case 'B':
 977                         options.bind_interface = optarg;
 978                         break;
 979                 case 'F':
 980                         config = optarg;
 981                         break;
 982                 default:
 983                         usage();
 984                 }
 985         }
 986
 987         if (optind > 1 && strcmp(av[optind - 1], "--") == 0)
 988                 opt_terminated = 1;
 989
 990         ac -= optind;
 991         av += optind;
 992
 993         if (ac > 0 && !host) {
 994                 int tport;
 995                 char *tuser;
 996                 switch (parse_ssh_uri(*av, &tuser, &host, &tport)) {
 997                 case -1:
 998                         usage();
 999                         break;
1000                 case 0:
1001                         if (options.user == NULL) {
1002                                 options.user = tuser;
1003                                 tuser = NULL;
1004                         }
1005                         free(tuser);
1006                         if (options.port == -1 && tport != -1)
1007                                 options.port = tport;
1008                         break;
1009                 default:
1010                         p = xstrdup(*av);
1011                         cp = strrchr(p, '@');
1012                         if (cp != NULL) {
1013                                 if (cp == p)
1014                                         usage();
1015                                 if (options.user == NULL) {
1016                                         options.user = p;
1017                                         p = NULL;
1018                                 }
1019                                 *cp++ = '\0';
1020                                 host = xstrdup(cp);
1021                                 free(p);
1022                         } else
1023                                 host = p;
1024                         break;
1025                 }
1026                 if (ac > 1 && !opt_terminated) {
1027                         optind = optreset = 1;
1028                         goto again;
1029                 }
1030                 ac--, av++;
1031         }
1032
1033         /* Check that we got a host name. */
1034         if (!host)
1035                 usage();
1036
1037         host_arg = xstrdup(host);
1038
1039 #ifdef WITH_OPENSSL
1040         OpenSSL_add_all_algorithms();
1041         ERR_load_crypto_strings();
1042 #endif
1043
1044         /* Initialize the command to execute on remote host. */
1045         buffer_init(&command);
1046
1047         /*
1048          * Save the command to execute on the remote host in a buffer. There
1049          * is no limit on the length of the command, except by the maximum
1050          * packet size.  Also sets the tty flag if there is no command.
1051          */
1052         if (!ac) {
1053                 /* No command specified - execute shell on a tty. */
1054                 if (subsystem_flag) {
1055                         fprintf(stderr,
1056                             "You must specify a subsystem to invoke.\n");
1057                         usage();
1058                 }
1059         } else {
1060                 /* A command has been specified.  Store it into the buffer. */
1061                 for (i = 0; i < ac; i++) {
1062                         if (i)
1063                                 buffer_append(&command, " ", 1);
1064                         buffer_append(&command, av[i], strlen(av[i]));
1065                 }
1066         }
1067
1068         /*
1069          * Initialize "log" output.  Since we are the client all output
1070          * goes to stderr unless otherwise specified by -y or -E.
1071          */
1072         if (use_syslog && logfile != NULL)
1073                 fatal("Can't specify both -y and -E");
1074         if (logfile != NULL)
1075                 log_redirect_stderr_to(logfile);
1076         log_init(argv0,
1077             options.log_level == SYSLOG_LEVEL_NOT_SET ?
1078             SYSLOG_LEVEL_INFO : options.log_level,
1079             options.log_facility == SYSLOG_FACILITY_NOT_SET ?
1080             SYSLOG_FACILITY_USER : options.log_facility,
1081             !use_syslog);
1082
1083         if (debug_flag)
1084                 logit("%s, %s", SSH_RELEASE,
1085 #ifdef WITH_OPENSSL
1086                     SSLeay_version(SSLEAY_VERSION)
1087 #else
1088                     "without OpenSSL"
1089 #endif
1090                 );
1091
1092         /* Parse the configuration files */
1093         process_config_files(host_arg, pw, 0);
1094
1095         /* Hostname canonicalisation needs a few options filled. */
1096         fill_default_options_for_canonicalization(&options);
1097
1098         /* If the user has replaced the hostname then take it into use now */
1099         if (options.hostname != NULL) {
1100                 /* NB. Please keep in sync with readconf.c:match_cfg_line() */
1101                 cp = percent_expand(options.hostname,
1102                     "h", host, (char *)NULL);
1103                 free(host);
1104                 host = cp;
1105                 free(options.hostname);
1106                 options.hostname = xstrdup(host);
1107         }
1108
1109         /* Don't lowercase addresses, they will be explicitly canonicalised */
1110         if ((was_addr = is_addr(host)) == 0)
1111                 lowercase(host);
1112
1113         /*
1114          * Try to canonicalize if requested by configuration or the
1115          * hostname is an address.
1116          */
1117         if (options.canonicalize_hostname != SSH_CANONICALISE_NO || was_addr)
1118                 addrs = resolve_canonicalize(&host, options.port);
1119
1120         /*
1121          * If CanonicalizePermittedCNAMEs have been specified but
1122          * other canonicalization did not happen (by not being requested
1123          * or by failing with fallback) then the hostname may still be changed
1124          * as a result of CNAME following.
1125          *
1126          * Try to resolve the bare hostname name using the system resolver's
1127          * usual search rules and then apply the CNAME follow rules.
1128          *
1129          * Skip the lookup if a ProxyCommand is being used unless the user
1130          * has specifically requested canonicalisation for this case via
1131          * CanonicalizeHostname=always
1132          */
1133         direct = option_clear_or_none(options.proxy_command) &&
1134             options.jump_host == NULL;
1135         if (addrs == NULL && options.num_permitted_cnames != 0 && (direct ||
1136             options.canonicalize_hostname == SSH_CANONICALISE_ALWAYS)) {
1137                 if ((addrs = resolve_host(host, options.port,
1138                     option_clear_or_none(options.proxy_command),
1139                     cname, sizeof(cname))) == NULL) {
1140                         /* Don't fatal proxied host names not in the DNS */
1141                         if (option_clear_or_none(options.proxy_command))
1142                                 cleanup_exit(255); /* logged in resolve_host */
1143                 } else
1144                         check_follow_cname(direct, &host, cname);
1145         }
1146
1147         /*
1148          * If canonicalisation is enabled then re-parse the configuration
1149          * files as new stanzas may match.
1150          */
1151         if (options.canonicalize_hostname != 0) {
1152                 debug("Re-reading configuration after hostname "
1153                     "canonicalisation");
1154                 free(options.hostname);
1155                 options.hostname = xstrdup(host);
1156                 process_config_files(host_arg, pw, 1);
1157                 /*
1158                  * Address resolution happens early with canonicalisation
1159                  * enabled and the port number may have changed since, so
1160                  * reset it in address list
1161                  */
1162                 if (addrs != NULL && options.port > 0)
1163                         set_addrinfo_port(addrs, options.port);
1164         }
1165
1166         /* Fill configuration defaults. */
1167         fill_default_options(&options);
1168
1169         /*
1170          * If ProxyJump option specified, then construct a ProxyCommand now.
1171          */
1172         if (options.jump_host != NULL) {
1173                 char port_s[8];
1174
1175                 /* Consistency check */
1176                 if (options.proxy_command != NULL)
1177                         fatal("inconsistent options: ProxyCommand+ProxyJump");
1178                 /* Never use FD passing for ProxyJump */
1179                 options.proxy_use_fdpass = 0;
1180                 snprintf(port_s, sizeof(port_s), "%d", options.jump_port);
1181                 xasprintf(&options.proxy_command,
1182                     "ssh%s%s%s%s%s%s%s%s%s%.*s -W '[%%h]:%%p' %s",
1183                     /* Optional "-l user" argument if jump_user set */
1184                     options.jump_user == NULL ? "" : " -l ",
1185                     options.jump_user == NULL ? "" : options.jump_user,
1186                     /* Optional "-p port" argument if jump_port set */
1187                     options.jump_port <= 0 ? "" : " -p ",
1188                     options.jump_port <= 0 ? "" : port_s,
1189                     /* Optional additional jump hosts ",..." */
1190                     options.jump_extra == NULL ? "" : " -J ",
1191                     options.jump_extra == NULL ? "" : options.jump_extra,
1192                     /* Optional "-F" argumment if -F specified */
1193                     config == NULL ? "" : " -F ",
1194                     config == NULL ? "" : config,
1195                     /* Optional "-v" arguments if -v set */
1196                     debug_flag ? " -" : "",
1197                     debug_flag, "vvv",
1198                     /* Mandatory hostname */
1199                     options.jump_host);
1200                 debug("Setting implicit ProxyCommand from ProxyJump: %s",
1201                     options.proxy_command);
1202         }
1203
1204         if (options.port == 0)
1205                 options.port = default_ssh_port();
1206         channel_set_af(ssh, options.address_family);
1207
1208         /* Tidy and check options */
1209         if (options.host_key_alias != NULL)
1210                 lowercase(options.host_key_alias);
1211         if (options.proxy_command != NULL &&
1212             strcmp(options.proxy_command, "-") == 0 &&
1213             options.proxy_use_fdpass)
1214                 fatal("ProxyCommand=- and ProxyUseFDPass are incompatible");
1215         if (options.control_persist &&
1216             options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK) {
1217                 debug("UpdateHostKeys=ask is incompatible with ControlPersist; "
1218                     "disabling");
1219                 options.update_hostkeys = 0;
1220         }
1221         if (options.connection_attempts <= 0)
1222                 fatal("Invalid number of ConnectionAttempts");
1223 #ifndef HAVE_CYGWIN
1224         if (original_effective_uid != 0)
1225                 options.use_privileged_port = 0;
1226 #endif
1227
1228         if (buffer_len(&command) != 0 && options.remote_command != NULL)
1229                 fatal("Cannot execute command-line and remote command.");
1230
1231         /* Cannot fork to background if no command. */
1232         if (fork_after_authentication_flag && buffer_len(&command) == 0 &&
1233             options.remote_command == NULL && !no_shell_flag)
1234                 fatal("Cannot fork into background without a command "
1235                     "to execute.");
1236
1237         /* reinit */
1238         log_init(argv0, options.log_level, options.log_facility, !use_syslog);
1239
1240         if (options.request_tty == REQUEST_TTY_YES ||
1241             options.request_tty == REQUEST_TTY_FORCE)
1242                 tty_flag = 1;
1243
1244         /* Allocate a tty by default if no command specified. */
1245         if (buffer_len(&command) == 0 && options.remote_command == NULL)
1246                 tty_flag = options.request_tty != REQUEST_TTY_NO;
1247
1248         /* Force no tty */
1249         if (options.request_tty == REQUEST_TTY_NO ||
1250             (muxclient_command && muxclient_command != SSHMUX_COMMAND_PROXY))
1251                 tty_flag = 0;
1252         /* Do not allocate a tty if stdin is not a tty. */
1253         if ((!isatty(fileno(stdin)) || stdin_null_flag) &&
1254             options.request_tty != REQUEST_TTY_FORCE) {
1255                 if (tty_flag)
1256                         logit("Pseudo-terminal will not be allocated because "
1257                             "stdin is not a terminal.");
1258                 tty_flag = 0;
1259         }
1260
1261         seed_rng();
1262
1263         if (options.user == NULL)
1264                 options.user = xstrdup(pw->pw_name);
1265
1266         /* Set up strings used to percent_expand() arguments */
1267         if (gethostname(thishost, sizeof(thishost)) == -1)
1268                 fatal("gethostname: %s", strerror(errno));
1269         strlcpy(shorthost, thishost, sizeof(shorthost));
1270         shorthost[strcspn(thishost, ".")] = '\0';
1271         snprintf(portstr, sizeof(portstr), "%d", options.port);
1272         snprintf(uidstr, sizeof(uidstr), "%d", pw->pw_uid);
1273
1274         if ((md = ssh_digest_start(SSH_DIGEST_SHA1)) == NULL ||
1275             ssh_digest_update(md, thishost, strlen(thishost)) < 0 ||
1276             ssh_digest_update(md, host, strlen(host)) < 0 ||
1277             ssh_digest_update(md, portstr, strlen(portstr)) < 0 ||
1278             ssh_digest_update(md, options.user, strlen(options.user)) < 0 ||
1279             ssh_digest_final(md, conn_hash, sizeof(conn_hash)) < 0)
1280                 fatal("%s: mux digest failed", __func__);
1281         ssh_digest_free(md);
1282         conn_hash_hex = tohex(conn_hash, ssh_digest_bytes(SSH_DIGEST_SHA1));
1283
1284         /*
1285          * Expand tokens in arguments. NB. LocalCommand is expanded later,
1286          * after port-forwarding is set up, so it may pick up any local
1287          * tunnel interface name allocated.
1288          */
1289         if (options.remote_command != NULL) {
1290                 debug3("expanding RemoteCommand: %s", options.remote_command);
1291                 cp = options.remote_command;
1292                 options.remote_command = percent_expand(cp,
1293                     "C", conn_hash_hex,
1294                     "L", shorthost,
1295                     "d", pw->pw_dir,
1296                     "h", host,
1297                     "l", thishost,
1298                     "n", host_arg,
1299                     "p", portstr,
1300                     "r", options.user,
1301                     "u", pw->pw_name,
1302                     (char *)NULL);
1303                 debug3("expanded RemoteCommand: %s", options.remote_command);
1304                 free(cp);
1305                 buffer_append(&command, options.remote_command,
1306                     strlen(options.remote_command));
1307         }
1308
1309         if (options.control_path != NULL) {
1310                 cp = tilde_expand_filename(options.control_path,
1311                     original_real_uid);
1312                 free(options.control_path);
1313                 options.control_path = percent_expand(cp,
1314                     "C", conn_hash_hex,
1315                     "L", shorthost,
1316                     "h", host,
1317                     "l", thishost,
1318                     "n", host_arg,
1319                     "p", portstr,
1320                     "r", options.user,
1321                     "u", pw->pw_name,
1322                     "i", uidstr,
1323                     (char *)NULL);
1324                 free(cp);
1325         }
1326         free(conn_hash_hex);
1327
1328         if (config_test) {
1329                 dump_client_config(&options, host);
1330                 exit(0);
1331         }
1332
1333         if (muxclient_command != 0 && options.control_path == NULL)
1334                 fatal("No ControlPath specified for \"-O\" command");
1335         if (options.control_path != NULL) {
1336                 int sock;
1337                 if ((sock = muxclient(options.control_path)) >= 0) {
1338                         ssh_packet_set_connection(ssh, sock, sock);
1339                         packet_set_mux();
1340                         goto skip_connect;
1341                 }
1342         }
1343
1344         /*
1345          * If hostname canonicalisation was not enabled, then we may not
1346          * have yet resolved the hostname. Do so now.
1347          */
1348         if (addrs == NULL && options.proxy_command == NULL) {
1349                 debug2("resolving \"%s\" port %d", host, options.port);
1350                 if ((addrs = resolve_host(host, options.port, 1,
1351                     cname, sizeof(cname))) == NULL)
1352                         cleanup_exit(255); /* resolve_host logs the error */
1353         }
1354
1355         timeout_ms = options.connection_timeout * 1000;
1356
1357         /* Open a connection to the remote host. */
1358         if (ssh_connect(ssh, host, addrs, &hostaddr, options.port,
1359             options.address_family, options.connection_attempts,
1360             &timeout_ms, options.tcp_keep_alive,
1361             options.use_privileged_port) != 0)
1362                 exit(255);
1363
1364         if (addrs != NULL)
1365                 freeaddrinfo(addrs);
1366
1367         packet_set_timeout(options.server_alive_interval,
1368             options.server_alive_count_max);
1369
1370         ssh = active_state; /* XXX */
1371
1372         if (timeout_ms > 0)
1373                 debug3("timeout: %d ms remain after connect", timeout_ms);
1374
1375         /*
1376          * If we successfully made the connection, load the host private key
1377          * in case we will need it later for combined rsa-rhosts
1378          * authentication. This must be done before releasing extra
1379          * privileges, because the file is only readable by root.
1380          * If we cannot access the private keys, load the public keys
1381          * instead and try to execute the ssh-keysign helper instead.
1382          */
1383         sensitive_data.nkeys = 0;
1384         sensitive_data.keys = NULL;
1385         sensitive_data.external_keysign = 0;
1386         if (options.hostbased_authentication) {
1387                 sensitive_data.nkeys = 11;
1388                 sensitive_data.keys = xcalloc(sensitive_data.nkeys,
1389                     sizeof(struct sshkey));     /* XXX */
1390                 for (i = 0; i < sensitive_data.nkeys; i++)
1391                         sensitive_data.keys[i] = NULL;
1392
1393                 PRIV_START;
1394 #ifdef OPENSSL_HAS_ECC
1395                 sensitive_data.keys[1] = key_load_private_cert(KEY_ECDSA,
1396                     _PATH_HOST_ECDSA_KEY_FILE, "", NULL);
1397 #endif
1398                 sensitive_data.keys[2] = key_load_private_cert(KEY_ED25519,
1399                     _PATH_HOST_ED25519_KEY_FILE, "", NULL);
1400                 sensitive_data.keys[3] = key_load_private_cert(KEY_RSA,
1401                     _PATH_HOST_RSA_KEY_FILE, "", NULL);
1402                 sensitive_data.keys[4] = key_load_private_cert(KEY_DSA,
1403                     _PATH_HOST_DSA_KEY_FILE, "", NULL);
1404 #ifdef OPENSSL_HAS_ECC
1405                 sensitive_data.keys[5] = key_load_private_type(KEY_ECDSA,
1406                     _PATH_HOST_ECDSA_KEY_FILE, "", NULL, NULL);
1407 #endif
1408                 sensitive_data.keys[6] = key_load_private_type(KEY_ED25519,
1409                     _PATH_HOST_ED25519_KEY_FILE, "", NULL, NULL);
1410                 sensitive_data.keys[7] = key_load_private_type(KEY_RSA,
1411                     _PATH_HOST_RSA_KEY_FILE, "", NULL, NULL);
1412                 sensitive_data.keys[8] = key_load_private_type(KEY_DSA,
1413                     _PATH_HOST_DSA_KEY_FILE, "", NULL, NULL);
1414                 sensitive_data.keys[9] = key_load_private_cert(KEY_XMSS,
1415                     _PATH_HOST_XMSS_KEY_FILE, "", NULL);
1416                 sensitive_data.keys[10] = key_load_private_type(KEY_XMSS,
1417                     _PATH_HOST_XMSS_KEY_FILE, "", NULL, NULL);
1418                 PRIV_END;
1419
1420                 if (options.hostbased_authentication == 1 &&
1421                     sensitive_data.keys[0] == NULL &&
1422                     sensitive_data.keys[5] == NULL &&
1423                     sensitive_data.keys[6] == NULL &&
1424                     sensitive_data.keys[7] == NULL &&
1425                     sensitive_data.keys[8] == NULL &&
1426                     sensitive_data.keys[9] == NULL) {
1427 #ifdef OPENSSL_HAS_ECC
1428                         sensitive_data.keys[1] = key_load_cert(
1429                             _PATH_HOST_ECDSA_KEY_FILE);
1430 #endif
1431                         sensitive_data.keys[2] = key_load_cert(
1432                             _PATH_HOST_ED25519_KEY_FILE);
1433                         sensitive_data.keys[3] = key_load_cert(
1434                             _PATH_HOST_RSA_KEY_FILE);
1435                         sensitive_data.keys[4] = key_load_cert(
1436                             _PATH_HOST_DSA_KEY_FILE);
1437 #ifdef OPENSSL_HAS_ECC
1438                         sensitive_data.keys[5] = key_load_public(
1439                             _PATH_HOST_ECDSA_KEY_FILE, NULL);
1440 #endif
1441                         sensitive_data.keys[6] = key_load_public(
1442                             _PATH_HOST_ED25519_KEY_FILE, NULL);
1443                         sensitive_data.keys[7] = key_load_public(
1444                             _PATH_HOST_RSA_KEY_FILE, NULL);
1445                         sensitive_data.keys[8] = key_load_public(
1446                             _PATH_HOST_DSA_KEY_FILE, NULL);
1447                         sensitive_data.keys[9] = key_load_cert(
1448                             _PATH_HOST_XMSS_KEY_FILE);
1449                         sensitive_data.keys[10] = key_load_public(
1450                             _PATH_HOST_XMSS_KEY_FILE, NULL);
1451                         sensitive_data.external_keysign = 1;
1452                 }
1453         }
1454         /*
1455          * Get rid of any extra privileges that we may have.  We will no
1456          * longer need them.  Also, extra privileges could make it very hard
1457          * to read identity files and other non-world-readable files from the
1458          * user's home directory if it happens to be on a NFS volume where
1459          * root is mapped to nobody.
1460          */
1461         if (original_effective_uid == 0) {
1462                 PRIV_START;
1463                 permanently_set_uid(pw);
1464         }
1465
1466         /*
1467          * Now that we are back to our own permissions, create ~/.ssh
1468          * directory if it doesn't already exist.
1469          */
1470         if (config == NULL) {
1471                 r = snprintf(buf, sizeof buf, "%s%s%s", pw->pw_dir,
1472                     strcmp(pw->pw_dir, "/") ? "/" : "", _PATH_SSH_USER_DIR);
1473                 if (r > 0 && (size_t)r < sizeof(buf) && stat(buf, &st) < 0) {
1474 #ifdef WITH_SELINUX
1475                         ssh_selinux_setfscreatecon(buf);
1476 #endif
1477                         if (mkdir(buf, 0700) < 0)
1478                                 error("Could not create directory '%.200s'.",
1479                                     buf);
1480 #ifdef WITH_SELINUX
1481                         ssh_selinux_setfscreatecon(NULL);
1482 #endif
1483                 }
1484         }
1485         /* load options.identity_files */
1486         load_public_identity_files(pw);
1487
1488         /* optionally set the SSH_AUTHSOCKET_ENV_NAME varibale */
1489         if (options.identity_agent &&
1490             strcmp(options.identity_agent, SSH_AUTHSOCKET_ENV_NAME) != 0) {
1491                 if (strcmp(options.identity_agent, "none") == 0) {
1492                         unsetenv(SSH_AUTHSOCKET_ENV_NAME);
1493                 } else {
1494                         p = tilde_expand_filename(options.identity_agent,
1495                             original_real_uid);
1496                         cp = percent_expand(p, "d", pw->pw_dir,
1497                             "u", pw->pw_name, "l", thishost, "h", host,
1498                             "r", options.user, (char *)NULL);
1499                         setenv(SSH_AUTHSOCKET_ENV_NAME, cp, 1);
1500                         free(cp);
1501                         free(p);
1502                 }
1503         }
1504
1505         /* Expand ~ in known host file names. */
1506         tilde_expand_paths(options.system_hostfiles,
1507             options.num_system_hostfiles);
1508         tilde_expand_paths(options.user_hostfiles, options.num_user_hostfiles);
1509
1510         signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */
1511         signal(SIGCHLD, main_sigchld_handler);
1512
1513         /* Log into the remote system.  Never returns if the login fails. */
1514         ssh_login(&sensitive_data, host, (struct sockaddr *)&hostaddr,
1515             options.port, pw, timeout_ms);
1516
1517         if (packet_connection_is_on_socket()) {
1518                 verbose("Authenticated to %s ([%s]:%d).", host,
1519                     ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
1520         } else {
1521                 verbose("Authenticated to %s (via proxy).", host);
1522         }
1523
1524         /* We no longer need the private host keys.  Clear them now. */
1525         if (sensitive_data.nkeys != 0) {
1526                 for (i = 0; i < sensitive_data.nkeys; i++) {
1527                         if (sensitive_data.keys[i] != NULL) {
1528                                 /* Destroys contents safely */
1529                                 debug3("clear hostkey %d", i);
1530                                 key_free(sensitive_data.keys[i]);
1531                                 sensitive_data.keys[i] = NULL;
1532                         }
1533                 }
1534                 free(sensitive_data.keys);
1535         }
1536         for (i = 0; i < options.num_identity_files; i++) {
1537                 free(options.identity_files[i]);
1538                 options.identity_files[i] = NULL;
1539                 if (options.identity_keys[i]) {
1540                         key_free(options.identity_keys[i]);
1541                         options.identity_keys[i] = NULL;
1542                 }
1543         }
1544         for (i = 0; i < options.num_certificate_files; i++) {
1545                 free(options.certificate_files[i]);
1546                 options.certificate_files[i] = NULL;
1547         }
1548
1549  skip_connect:
1550         exit_status = ssh_session2(ssh, pw);
1551         packet_close();
1552
1553         if (options.control_path != NULL && muxserver_sock != -1)
1554                 unlink(options.control_path);
1555
1556         /* Kill ProxyCommand if it is running. */
1557         ssh_kill_proxy_command();
1558
1559         return exit_status;
1560 }
1561
1562 static void
1563 control_persist_detach(void)
1564 {
1565         pid_t pid;
1566         int devnull, keep_stderr;
1567
1568         debug("%s: backgrounding master process", __func__);
1569
1570         /*
1571          * master (current process) into the background, and make the
1572          * foreground process a client of the backgrounded master.
1573          */
1574         switch ((pid = fork())) {
1575         case -1:
1576                 fatal("%s: fork: %s", __func__, strerror(errno));
1577         case 0:
1578                 /* Child: master process continues mainloop */
1579                 break;
1580         default:
1581                 /* Parent: set up mux slave to connect to backgrounded master */
1582                 debug2("%s: background process is %ld", __func__, (long)pid);
1583                 stdin_null_flag = ostdin_null_flag;
1584                 options.request_tty = orequest_tty;
1585                 tty_flag = otty_flag;
1586                 close(muxserver_sock);
1587                 muxserver_sock = -1;
1588                 options.control_master = SSHCTL_MASTER_NO;
1589                 muxclient(options.control_path);
1590                 /* muxclient() doesn't return on success. */
1591                 fatal("Failed to connect to new control master");
1592         }
1593         if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1) {
1594                 error("%s: open(\"/dev/null\"): %s", __func__,
1595                     strerror(errno));
1596         } else {
1597                 keep_stderr = log_is_on_stderr() && debug_flag;
1598                 if (dup2(devnull, STDIN_FILENO) == -1 ||
1599                     dup2(devnull, STDOUT_FILENO) == -1 ||
1600                     (!keep_stderr && dup2(devnull, STDERR_FILENO) == -1))
1601                         error("%s: dup2: %s", __func__, strerror(errno));
1602                 if (devnull > STDERR_FILENO)
1603                         close(devnull);
1604         }
1605         daemon(1, 1);
1606         setproctitle("%s [mux]", options.control_path);
1607 }
1608
1609 /* Do fork() after authentication. Used by "ssh -f" */
1610 static void
1611 fork_postauth(void)
1612 {
1613         if (need_controlpersist_detach)
1614                 control_persist_detach();
1615         debug("forking to background");
1616         fork_after_authentication_flag = 0;
1617         if (daemon(1, 1) < 0)
1618                 fatal("daemon() failed: %.200s", strerror(errno));
1619 }
1620
1621 /* Callback for remote forward global requests */
1622 static void
1623 ssh_confirm_remote_forward(struct ssh *ssh, int type, u_int32_t seq, void *ctxt)
1624 {
1625         struct Forward *rfwd = (struct Forward *)ctxt;
1626
1627         /* XXX verbose() on failure? */
1628         debug("remote forward %s for: listen %s%s%d, connect %s:%d",
1629             type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure",
1630             rfwd->listen_path ? rfwd->listen_path :
1631             rfwd->listen_host ? rfwd->listen_host : "",
1632             (rfwd->listen_path || rfwd->listen_host) ? ":" : "",
1633             rfwd->listen_port, rfwd->connect_path ? rfwd->connect_path :
1634             rfwd->connect_host, rfwd->connect_port);
1635         if (rfwd->listen_path == NULL && rfwd->listen_port == 0) {
1636                 if (type == SSH2_MSG_REQUEST_SUCCESS) {
1637                         rfwd->allocated_port = packet_get_int();
1638                         logit("Allocated port %u for remote forward to %s:%d",
1639                             rfwd->allocated_port,
1640                             rfwd->connect_host, rfwd->connect_port);
1641                         channel_update_permitted_opens(ssh,
1642                             rfwd->handle, rfwd->allocated_port);
1643                 } else {
1644                         channel_update_permitted_opens(ssh, rfwd->handle, -1);
1645                 }
1646         }
1647
1648         if (type == SSH2_MSG_REQUEST_FAILURE) {
1649                 if (options.exit_on_forward_failure) {
1650                         if (rfwd->listen_path != NULL)
1651                                 fatal("Error: remote port forwarding failed "
1652                                     "for listen path %s", rfwd->listen_path);
1653                         else
1654                                 fatal("Error: remote port forwarding failed "
1655                                     "for listen port %d", rfwd->listen_port);
1656                 } else {
1657                         if (rfwd->listen_path != NULL)
1658                                 logit("Warning: remote port forwarding failed "
1659                                     "for listen path %s", rfwd->listen_path);
1660                         else
1661                                 logit("Warning: remote port forwarding failed "
1662                                     "for listen port %d", rfwd->listen_port);
1663                 }
1664         }
1665         if (++remote_forward_confirms_received == options.num_remote_forwards) {
1666                 debug("All remote forwarding requests processed");
1667                 if (fork_after_authentication_flag)
1668                         fork_postauth();
1669         }
1670 }
1671
1672 static void
1673 client_cleanup_stdio_fwd(struct ssh *ssh, int id, void *arg)
1674 {
1675         debug("stdio forwarding: done");
1676         cleanup_exit(0);
1677 }
1678
1679 static void
1680 ssh_stdio_confirm(struct ssh *ssh, int id, int success, void *arg)
1681 {
1682         if (!success)
1683                 fatal("stdio forwarding failed");
1684 }
1685
1686 static void
1687 ssh_init_stdio_forwarding(struct ssh *ssh)
1688 {
1689         Channel *c;
1690         int in, out;
1691
1692         if (options.stdio_forward_host == NULL)
1693                 return;
1694
1695         debug3("%s: %s:%d", __func__, options.stdio_forward_host,
1696             options.stdio_forward_port);
1697
1698         if ((in = dup(STDIN_FILENO)) < 0 ||
1699             (out = dup(STDOUT_FILENO)) < 0)
1700                 fatal("channel_connect_stdio_fwd: dup() in/out failed");
1701         if ((c = channel_connect_stdio_fwd(ssh, options.stdio_forward_host,
1702             options.stdio_forward_port, in, out)) == NULL)
1703                 fatal("%s: channel_connect_stdio_fwd failed", __func__);
1704         channel_register_cleanup(ssh, c->self, client_cleanup_stdio_fwd, 0);
1705         channel_register_open_confirm(ssh, c->self, ssh_stdio_confirm, NULL);
1706 }
1707
1708 static void
1709 ssh_init_forwarding(struct ssh *ssh, char **ifname)
1710 {
1711         int success = 0;
1712         int i;
1713
1714         /* Initiate local TCP/IP port forwardings. */
1715         for (i = 0; i < options.num_local_forwards; i++) {
1716                 debug("Local connections to %.200s:%d forwarded to remote "
1717                     "address %.200s:%d",
1718                     (options.local_forwards[i].listen_path != NULL) ?
1719                     options.local_forwards[i].listen_path :
1720                     (options.local_forwards[i].listen_host == NULL) ?
1721                     (options.fwd_opts.gateway_ports ? "*" : "LOCALHOST") :
1722                     options.local_forwards[i].listen_host,
1723                     options.local_forwards[i].listen_port,
1724                     (options.local_forwards[i].connect_path != NULL) ?
1725                     options.local_forwards[i].connect_path :
1726                     options.local_forwards[i].connect_host,
1727                     options.local_forwards[i].connect_port);
1728                 success += channel_setup_local_fwd_listener(ssh,
1729                     &options.local_forwards[i], &options.fwd_opts);
1730         }
1731         if (i > 0 && success != i && options.exit_on_forward_failure)
1732                 fatal("Could not request local forwarding.");
1733         if (i > 0 && success == 0)
1734                 error("Could not request local forwarding.");
1735
1736         /* Initiate remote TCP/IP port forwardings. */
1737         for (i = 0; i < options.num_remote_forwards; i++) {
1738                 debug("Remote connections from %.200s:%d forwarded to "
1739                     "local address %.200s:%d",
1740                     (options.remote_forwards[i].listen_path != NULL) ?
1741                     options.remote_forwards[i].listen_path :
1742                     (options.remote_forwards[i].listen_host == NULL) ?
1743                     "LOCALHOST" : options.remote_forwards[i].listen_host,
1744                     options.remote_forwards[i].listen_port,
1745                     (options.remote_forwards[i].connect_path != NULL) ?
1746                     options.remote_forwards[i].connect_path :
1747                     options.remote_forwards[i].connect_host,
1748                     options.remote_forwards[i].connect_port);
1749                 options.remote_forwards[i].handle =
1750                     channel_request_remote_forwarding(ssh,
1751                     &options.remote_forwards[i]);
1752                 if (options.remote_forwards[i].handle < 0) {
1753                         if (options.exit_on_forward_failure)
1754                                 fatal("Could not request remote forwarding.");
1755                         else
1756                                 logit("Warning: Could not request remote "
1757                                     "forwarding.");
1758                 } else {
1759                         client_register_global_confirm(
1760                             ssh_confirm_remote_forward,
1761                             &options.remote_forwards[i]);
1762                 }
1763         }
1764
1765         /* Initiate tunnel forwarding. */
1766         if (options.tun_open != SSH_TUNMODE_NO) {
1767                 if ((*ifname = client_request_tun_fwd(ssh,
1768                     options.tun_open, options.tun_local,
1769                     options.tun_remote)) == NULL) {
1770                         if (options.exit_on_forward_failure)
1771                                 fatal("Could not request tunnel forwarding.");
1772                         else
1773                                 error("Could not request tunnel forwarding.");
1774                 }
1775         }
1776 }
1777
1778 static void
1779 check_agent_present(void)
1780 {
1781         int r;
1782
1783         if (options.forward_agent) {
1784                 /* Clear agent forwarding if we don't have an agent. */
1785                 if ((r = ssh_get_authentication_socket(NULL)) != 0) {
1786                         options.forward_agent = 0;
1787                         if (r != SSH_ERR_AGENT_NOT_PRESENT)
1788                                 debug("ssh_get_authentication_socket: %s",
1789                                     ssh_err(r));
1790                 }
1791         }
1792 }
1793
1794 static void
1795 ssh_session2_setup(struct ssh *ssh, int id, int success, void *arg)
1796 {
1797         extern char **environ;
1798         const char *display;
1799         int interactive = tty_flag;
1800         char *proto = NULL, *data = NULL;
1801
1802         if (!success)
1803                 return; /* No need for error message, channels code sens one */
1804
1805         display = getenv("DISPLAY");
1806         if (display == NULL && options.forward_x11)
1807                 debug("X11 forwarding requested but DISPLAY not set");
1808         if (options.forward_x11 && client_x11_get_proto(ssh, display,
1809             options.xauth_location, options.forward_x11_trusted,
1810             options.forward_x11_timeout, &proto, &data) == 0) {
1811                 /* Request forwarding with authentication spoofing. */
1812                 debug("Requesting X11 forwarding with authentication "
1813                     "spoofing.");
1814                 x11_request_forwarding_with_spoofing(ssh, id, display, proto,
1815                     data, 1);
1816                 client_expect_confirm(ssh, id, "X11 forwarding", CONFIRM_WARN);
1817                 /* XXX exit_on_forward_failure */
1818                 interactive = 1;
1819         }
1820
1821         check_agent_present();
1822         if (options.forward_agent) {
1823                 debug("Requesting authentication agent forwarding.");
1824                 channel_request_start(ssh, id, "auth-agent-req@openssh.com", 0);
1825                 packet_send();
1826         }
1827
1828         /* Tell the packet module whether this is an interactive session. */
1829         packet_set_interactive(interactive,
1830             options.ip_qos_interactive, options.ip_qos_bulk);
1831
1832         client_session2_setup(ssh, id, tty_flag, subsystem_flag, getenv("TERM"),
1833             NULL, fileno(stdin), &command, environ);
1834 }
1835
1836 /* open new channel for a session */
1837 static int
1838 ssh_session2_open(struct ssh *ssh)
1839 {
1840         Channel *c;
1841         int window, packetmax, in, out, err;
1842
1843         if (stdin_null_flag) {
1844                 in = open(_PATH_DEVNULL, O_RDONLY);
1845         } else {
1846                 in = dup(STDIN_FILENO);
1847         }
1848         out = dup(STDOUT_FILENO);
1849         err = dup(STDERR_FILENO);
1850
1851         if (in < 0 || out < 0 || err < 0)
1852                 fatal("dup() in/out/err failed");
1853
1854         /* enable nonblocking unless tty */
1855         if (!isatty(in))
1856                 set_nonblock(in);
1857         if (!isatty(out))
1858                 set_nonblock(out);
1859         if (!isatty(err))
1860                 set_nonblock(err);
1861
1862         window = CHAN_SES_WINDOW_DEFAULT;
1863         packetmax = CHAN_SES_PACKET_DEFAULT;
1864         if (tty_flag) {
1865                 window >>= 1;
1866                 packetmax >>= 1;
1867         }
1868         c = channel_new(ssh,
1869             "session", SSH_CHANNEL_OPENING, in, out, err,
1870             window, packetmax, CHAN_EXTENDED_WRITE,
1871             "client-session", /*nonblock*/0);
1872
1873         debug3("%s: channel_new: %d", __func__, c->self);
1874
1875         channel_send_open(ssh, c->self);
1876         if (!no_shell_flag)
1877                 channel_register_open_confirm(ssh, c->self,
1878                     ssh_session2_setup, NULL);
1879
1880         return c->self;
1881 }
1882
1883 static int
1884 ssh_session2(struct ssh *ssh, struct passwd *pw)
1885 {
1886         int devnull, id = -1;
1887         char *cp, *tun_fwd_ifname = NULL;
1888
1889         /* XXX should be pre-session */
1890         if (!options.control_persist)
1891                 ssh_init_stdio_forwarding(ssh);
1892
1893         ssh_init_forwarding(ssh, &tun_fwd_ifname);
1894
1895         if (options.local_command != NULL) {
1896                 debug3("expanding LocalCommand: %s", options.local_command);
1897                 cp = options.local_command;
1898                 options.local_command = percent_expand(cp,
1899                     "C", conn_hash_hex,
1900                     "L", shorthost,
1901                     "d", pw->pw_dir,
1902                     "h", host,
1903                     "l", thishost,
1904                     "n", host_arg,
1905                     "p", portstr,
1906                     "r", options.user,
1907                     "u", pw->pw_name,
1908                     "T", tun_fwd_ifname == NULL ? "NONE" : tun_fwd_ifname,
1909                     (char *)NULL);
1910                 debug3("expanded LocalCommand: %s", options.local_command);
1911                 free(cp);
1912         }
1913
1914         /* Start listening for multiplex clients */
1915         if (!packet_get_mux())
1916                 muxserver_listen(ssh);
1917
1918         /*
1919          * If we are in control persist mode and have a working mux listen
1920          * socket, then prepare to background ourselves and have a foreground
1921          * client attach as a control slave.
1922          * NB. we must save copies of the flags that we override for
1923          * the backgrounding, since we defer attachment of the slave until
1924          * after the connection is fully established (in particular,
1925          * async rfwd replies have been received for ExitOnForwardFailure).
1926          */
1927         if (options.control_persist && muxserver_sock != -1) {
1928                 ostdin_null_flag = stdin_null_flag;
1929                 ono_shell_flag = no_shell_flag;
1930                 orequest_tty = options.request_tty;
1931                 otty_flag = tty_flag;
1932                 stdin_null_flag = 1;
1933                 no_shell_flag = 1;
1934                 tty_flag = 0;
1935                 if (!fork_after_authentication_flag)
1936                         need_controlpersist_detach = 1;
1937                 fork_after_authentication_flag = 1;
1938         }
1939         /*
1940          * ControlPersist mux listen socket setup failed, attempt the
1941          * stdio forward setup that we skipped earlier.
1942          */
1943         if (options.control_persist && muxserver_sock == -1)
1944                 ssh_init_stdio_forwarding(ssh);
1945
1946         if (!no_shell_flag)
1947                 id = ssh_session2_open(ssh);
1948         else {
1949                 packet_set_interactive(
1950                     options.control_master == SSHCTL_MASTER_NO,
1951                     options.ip_qos_interactive, options.ip_qos_bulk);
1952         }
1953
1954         /* If we don't expect to open a new session, then disallow it */
1955         if (options.control_master == SSHCTL_MASTER_NO &&
1956             (datafellows & SSH_NEW_OPENSSH)) {
1957                 debug("Requesting no-more-sessions@openssh.com");
1958                 packet_start(SSH2_MSG_GLOBAL_REQUEST);
1959                 packet_put_cstring("no-more-sessions@openssh.com");
1960                 packet_put_char(0);
1961                 packet_send();
1962         }
1963
1964         /* Execute a local command */
1965         if (options.local_command != NULL &&
1966             options.permit_local_command)
1967                 ssh_local_cmd(options.local_command);
1968
1969         /*
1970          * stdout is now owned by the session channel; clobber it here
1971          * so future channel closes are propagated to the local fd.
1972          * NB. this can only happen after LocalCommand has completed,
1973          * as it may want to write to stdout.
1974          */
1975         if (!need_controlpersist_detach) {
1976                 if ((devnull = open(_PATH_DEVNULL, O_WRONLY)) == -1)
1977                         error("%s: open %s: %s", __func__,
1978                             _PATH_DEVNULL, strerror(errno));
1979                 if (dup2(devnull, STDOUT_FILENO) < 0)
1980                         fatal("%s: dup2() stdout failed", __func__);
1981                 if (devnull > STDERR_FILENO)
1982                         close(devnull);
1983         }
1984
1985         /*
1986          * If requested and we are not interested in replies to remote
1987          * forwarding requests, then let ssh continue in the background.
1988          */
1989         if (fork_after_authentication_flag) {
1990                 if (options.exit_on_forward_failure &&
1991                     options.num_remote_forwards > 0) {
1992                         debug("deferring postauth fork until remote forward "
1993                             "confirmation received");
1994                 } else
1995                         fork_postauth();
1996         }
1997
1998         return client_loop(ssh, tty_flag, tty_flag ?
1999             options.escape_char : SSH_ESCAPECHAR_NONE, id);
2000 }
2001
2002 /* Loads all IdentityFile and CertificateFile keys */
2003 static void
2004 load_public_identity_files(struct passwd *pw)
2005 {
2006         char *filename, *cp;
2007         struct sshkey *public;
2008         int i;
2009         u_int n_ids, n_certs;
2010         char *identity_files[SSH_MAX_IDENTITY_FILES];
2011         struct sshkey *identity_keys[SSH_MAX_IDENTITY_FILES];
2012         char *certificate_files[SSH_MAX_CERTIFICATE_FILES];
2013         struct sshkey *certificates[SSH_MAX_CERTIFICATE_FILES];
2014 #ifdef ENABLE_PKCS11
2015         struct sshkey **keys;
2016         int nkeys;
2017 #endif /* PKCS11 */
2018
2019         n_ids = n_certs = 0;
2020         memset(identity_files, 0, sizeof(identity_files));
2021         memset(identity_keys, 0, sizeof(identity_keys));
2022         memset(certificate_files, 0, sizeof(certificate_files));
2023         memset(certificates, 0, sizeof(certificates));
2024
2025 #ifdef ENABLE_PKCS11
2026         if (options.pkcs11_provider != NULL &&
2027             options.num_identity_files < SSH_MAX_IDENTITY_FILES &&
2028             (pkcs11_init(!options.batch_mode) == 0) &&
2029             (nkeys = pkcs11_add_provider(options.pkcs11_provider, NULL,
2030             &keys)) > 0) {
2031                 for (i = 0; i < nkeys; i++) {
2032                         if (n_ids >= SSH_MAX_IDENTITY_FILES) {
2033                                 key_free(keys[i]);
2034                                 continue;
2035                         }
2036                         identity_keys[n_ids] = keys[i];
2037                         identity_files[n_ids] =
2038                             xstrdup(options.pkcs11_provider); /* XXX */
2039                         n_ids++;
2040                 }
2041                 free(keys);
2042         }
2043 #endif /* ENABLE_PKCS11 */
2044         if ((pw = getpwuid(original_real_uid)) == NULL)
2045                 fatal("load_public_identity_files: getpwuid failed");
2046         for (i = 0; i < options.num_identity_files; i++) {
2047                 if (n_ids >= SSH_MAX_IDENTITY_FILES ||
2048                     strcasecmp(options.identity_files[i], "none") == 0) {
2049                         free(options.identity_files[i]);
2050                         options.identity_files[i] = NULL;
2051                         continue;
2052                 }
2053                 cp = tilde_expand_filename(options.identity_files[i],
2054                     original_real_uid);
2055                 filename = percent_expand(cp, "d", pw->pw_dir,
2056                     "u", pw->pw_name, "l", thishost, "h", host,
2057                     "r", options.user, (char *)NULL);
2058                 free(cp);
2059                 public = key_load_public(filename, NULL);
2060                 debug("identity file %s type %d", filename,
2061                     public ? public->type : -1);
2062                 free(options.identity_files[i]);
2063                 identity_files[n_ids] = filename;
2064                 identity_keys[n_ids] = public;
2065
2066                 if (++n_ids >= SSH_MAX_IDENTITY_FILES)
2067                         continue;
2068
2069                 /*
2070                  * If no certificates have been explicitly listed then try
2071                  * to add the default certificate variant too.
2072                  */
2073                 if (options.num_certificate_files != 0)
2074                         continue;
2075                 xasprintf(&cp, "%s-cert", filename);
2076                 public = key_load_public(cp, NULL);
2077                 debug("identity file %s type %d", cp,
2078                     public ? public->type : -1);
2079                 if (public == NULL) {
2080                         free(cp);
2081                         continue;
2082                 }
2083                 if (!key_is_cert(public)) {
2084                         debug("%s: key %s type %s is not a certificate",
2085                             __func__, cp, key_type(public));
2086                         key_free(public);
2087                         free(cp);
2088                         continue;
2089                 }
2090                 /* NB. leave filename pointing to private key */
2091                 identity_files[n_ids] = xstrdup(filename);
2092                 identity_keys[n_ids] = public;
2093                 n_ids++;
2094         }
2095
2096         if (options.num_certificate_files > SSH_MAX_CERTIFICATE_FILES)
2097                 fatal("%s: too many certificates", __func__);
2098         for (i = 0; i < options.num_certificate_files; i++) {
2099                 cp = tilde_expand_filename(options.certificate_files[i],
2100                     original_real_uid);
2101                 filename = percent_expand(cp, "d", pw->pw_dir,
2102                     "u", pw->pw_name, "l", thishost, "h", host,
2103                     "r", options.user, (char *)NULL);
2104                 free(cp);
2105
2106                 public = key_load_public(filename, NULL);
2107                 debug("certificate file %s type %d", filename,
2108                     public ? public->type : -1);
2109                 free(options.certificate_files[i]);
2110                 options.certificate_files[i] = NULL;
2111                 if (public == NULL) {
2112                         free(filename);
2113                         continue;
2114                 }
2115                 if (!key_is_cert(public)) {
2116                         debug("%s: key %s type %s is not a certificate",
2117                             __func__, filename, key_type(public));
2118                         key_free(public);
2119                         free(filename);
2120                         continue;
2121                 }
2122                 certificate_files[n_certs] = filename;
2123                 certificates[n_certs] = public;
2124                 ++n_certs;
2125         }
2126
2127         options.num_identity_files = n_ids;
2128         memcpy(options.identity_files, identity_files, sizeof(identity_files));
2129         memcpy(options.identity_keys, identity_keys, sizeof(identity_keys));
2130
2131         options.num_certificate_files = n_certs;
2132         memcpy(options.certificate_files,
2133             certificate_files, sizeof(certificate_files));
2134         memcpy(options.certificates, certificates, sizeof(certificates));
2135 }
2136
2137 static void
2138 main_sigchld_handler(int sig)
2139 {
2140         int save_errno = errno;
2141         pid_t pid;
2142         int status;
2143
2144         while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
2145             (pid < 0 && errno == EINTR))
2146                 ;
2147         errno = save_errno;
2148 }