crypto/openssh/ssh.c

   1 /* $OpenBSD: ssh.c,v 1.451 2017/03/10 04:07:20 djm Exp $ */
   2 /*
   3  * Author: Tatu Ylonen <ylo@cs.hut.fi>
   4  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
   5  *                    All rights reserved
   6  * Ssh client program.  This program can be used to log into a remote machine.
   7  * The software supports strong authentication, encryption, and forwarding
   8  * of X11, TCP/IP, and authentication connections.
   9  *
  10  * As far as I am concerned, the code I have written for this software
  11  * can be used freely for any purpose.  Any derived versions of this
  12  * software must be clearly marked as such, and if the derived work is
  13  * incompatible with the protocol description in the RFC file, it must be
  14  * called by a name other than "ssh" or "Secure Shell".
  15  *
  16  * Copyright (c) 1999 Niels Provos.  All rights reserved.
  17  * Copyright (c) 2000, 2001, 2002, 2003 Markus Friedl.  All rights reserved.
  18  *
  19  * Modified to work with 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 __RCSID("$FreeBSD$");
  45
  46 #include <sys/types.h>
  47 #ifdef HAVE_SYS_STAT_H
  48 # include <sys/stat.h>
  49 #endif
  50 #include <sys/resource.h>
  51 #include <sys/ioctl.h>
  52 #include <sys/socket.h>
  53 #include <sys/wait.h>
  54
  55 #include <ctype.h>
  56 #include <errno.h>
  57 #include <fcntl.h>
  58 #include <netdb.h>
  59 #ifdef HAVE_PATHS_H
  60 #include <paths.h>
  61 #endif
  62 #include <pwd.h>
  63 #include <signal.h>
  64 #include <stdarg.h>
  65 #include <stddef.h>
  66 #include <stdio.h>
  67 #include <stdlib.h>
  68 #include <string.h>
  69 #include <unistd.h>
  70 #include <limits.h>
  71 #include <locale.h>
  72
  73 #include <netinet/in.h>
  74 #include <arpa/inet.h>
  75
  76 #ifdef WITH_OPENSSL
  77 #include <openssl/evp.h>
  78 #include <openssl/err.h>
  79 #endif
  80 #include "openbsd-compat/openssl-compat.h"
  81 #include "openbsd-compat/sys-queue.h"
  82
  83 #include "xmalloc.h"
  84 #include "ssh.h"
  85 #include "ssh1.h"
  86 #include "ssh2.h"
  87 #include "canohost.h"
  88 #include "compat.h"
  89 #include "cipher.h"
  90 #include "digest.h"
  91 #include "packet.h"
  92 #include "buffer.h"
  93 #include "channels.h"
  94 #include "key.h"
  95 #include "authfd.h"
  96 #include "authfile.h"
  97 #include "pathnames.h"
  98 #include "dispatch.h"
  99 #include "clientloop.h"
 100 #include "log.h"
 101 #include "misc.h"
 102 #include "readconf.h"
 103 #include "sshconnect.h"
 104 #include "kex.h"
 105 #include "mac.h"
 106 #include "sshpty.h"
 107 #include "match.h"
 108 #include "msg.h"
 109 #include "uidswap.h"
 110 #include "version.h"
 111 #include "ssherr.h"
 112 #include "myproposal.h"
 113 #include "utf8.h"
 114
 115 #ifdef ENABLE_PKCS11
 116 #include "ssh-pkcs11.h"
 117 #endif
 118
 119 extern char *__progname;
 120
 121 /* Saves a copy of argv for setproctitle emulation */
 122 #ifndef HAVE_SETPROCTITLE
 123 static char **saved_av;
 124 #endif
 125
 126 /* Flag indicating whether debug mode is on.  May be set on the command line. */
 127 int debug_flag = 0;
 128
 129 /* Flag indicating whether a tty should be requested */
 130 int tty_flag = 0;
 131
 132 /* don't exec a shell */
 133 int no_shell_flag = 0;
 134
 135 /*
 136  * Flag indicating that nothing should be read from stdin.  This can be set
 137  * on the command line.
 138  */
 139 int stdin_null_flag = 0;
 140
 141 /*
 142  * Flag indicating that the current process should be backgrounded and
 143  * a new slave launched in the foreground for ControlPersist.
 144  */
 145 int need_controlpersist_detach = 0;
 146
 147 /* Copies of flags for ControlPersist foreground slave */
 148 int ostdin_null_flag, ono_shell_flag, otty_flag, orequest_tty;
 149
 150 /*
 151  * Flag indicating that ssh should fork after authentication.  This is useful
 152  * so that the passphrase can be entered manually, and then ssh goes to the
 153  * background.
 154  */
 155 int fork_after_authentication_flag = 0;
 156
 157 /*
 158  * General data structure for command line options and options configurable
 159  * in configuration files.  See readconf.h.
 160  */
 161 Options options;
 162
 163 /* optional user configfile */
 164 char *config = NULL;
 165
 166 /*
 167  * Name of the host we are connecting to.  This is the name given on the
 168  * command line, or the HostName specified for the user-supplied name in a
 169  * configuration file.
 170  */
 171 char *host;
 172
 173 /* socket address the host resolves to */
 174 struct sockaddr_storage hostaddr;
 175
 176 /* Private host keys. */
 177 Sensitive sensitive_data;
 178
 179 /* Original real UID. */
 180 uid_t original_real_uid;
 181 uid_t original_effective_uid;
 182
 183 /* command to be executed */
 184 Buffer command;
 185
 186 /* Should we execute a command or invoke a subsystem? */
 187 int subsystem_flag = 0;
 188
 189 /* # of replies received for global requests */
 190 static int remote_forward_confirms_received = 0;
 191
 192 /* mux.c */
 193 extern int muxserver_sock;
 194 extern u_int muxclient_command;
 195
 196 /* Prints a help message to the user.  This function never returns. */
 197
 198 static void
 199 usage(void)
 200 {
 201         fprintf(stderr,
 202 "usage: ssh [-1246AaCfGgKkMNnqsTtVvXxYy] [-b bind_address] [-c cipher_spec]\n"
 203 "           [-D [bind_address:]port] [-E log_file] [-e escape_char]\n"
 204 "           [-F configfile] [-I pkcs11] [-i identity_file]\n"
 205 "           [-J [user@]host[:port]] [-L address] [-l login_name] [-m mac_spec]\n"
 206 "           [-O ctl_cmd] [-o option] [-p port] [-Q query_option] [-R address]\n"
 207 "           [-S ctl_path] [-W host:port] [-w local_tun[:remote_tun]]\n"
 208 "           [user@]hostname [command]\n"
 209         );
 210         exit(255);
 211 }
 212
 213 static int ssh_session(void);
 214 static int ssh_session2(void);
 215 static void load_public_identity_files(void);
 216 static void main_sigchld_handler(int);
 217
 218 /* ~/ expand a list of paths. NB. assumes path[n] is heap-allocated. */
 219 static void
 220 tilde_expand_paths(char **paths, u_int num_paths)
 221 {
 222         u_int i;
 223         char *cp;
 224
 225         for (i = 0; i < num_paths; i++) {
 226                 cp = tilde_expand_filename(paths[i], original_real_uid);
 227                 free(paths[i]);
 228                 paths[i] = cp;
 229         }
 230 }
 231
 232 /*
 233  * Attempt to resolve a host name / port to a set of addresses and
 234  * optionally return any CNAMEs encountered along the way.
 235  * Returns NULL on failure.
 236  * NB. this function must operate with a options having undefined members.
 237  */
 238 static struct addrinfo *
 239 resolve_host(const char *name, int port, int logerr, char *cname, size_t clen)
 240 {
 241         char strport[NI_MAXSERV];
 242         struct addrinfo hints, *res;
 243         int gaierr, loglevel = SYSLOG_LEVEL_DEBUG1;
 244
 245         if (port <= 0)
 246                 port = default_ssh_port();
 247
 248         snprintf(strport, sizeof strport, "%d", port);
 249         memset(&hints, 0, sizeof(hints));
 250         hints.ai_family = options.address_family == -1 ?
 251             AF_UNSPEC : options.address_family;
 252         hints.ai_socktype = SOCK_STREAM;
 253         if (cname != NULL)
 254                 hints.ai_flags = AI_CANONNAME;
 255         if ((gaierr = getaddrinfo(name, strport, &hints, &res)) != 0) {
 256                 if (logerr || (gaierr != EAI_NONAME && gaierr != EAI_NODATA))
 257                         loglevel = SYSLOG_LEVEL_ERROR;
 258                 do_log2(loglevel, "%s: Could not resolve hostname %.100s: %s",
 259                     __progname, name, ssh_gai_strerror(gaierr));
 260                 return NULL;
 261         }
 262         if (cname != NULL && res->ai_canonname != NULL) {
 263                 if (strlcpy(cname, res->ai_canonname, clen) >= clen) {
 264                         error("%s: host \"%s\" cname \"%s\" too long (max %lu)",
 265                             __func__, name,  res->ai_canonname, (u_long)clen);
 266                         if (clen > 0)
 267                                 *cname = '\0';
 268                 }
 269         }
 270         return res;
 271 }
 272
 273 /*
 274  * Attempt to resolve a numeric host address / port to a single address.
 275  * Returns a canonical address string.
 276  * Returns NULL on failure.
 277  * NB. this function must operate with a options having undefined members.
 278  */
 279 static struct addrinfo *
 280 resolve_addr(const char *name, int port, char *caddr, size_t clen)
 281 {
 282         char addr[NI_MAXHOST], strport[NI_MAXSERV];
 283         struct addrinfo hints, *res;
 284         int gaierr;
 285
 286         if (port <= 0)
 287                 port = default_ssh_port();
 288         snprintf(strport, sizeof strport, "%u", port);
 289         memset(&hints, 0, sizeof(hints));
 290         hints.ai_family = options.address_family == -1 ?
 291             AF_UNSPEC : options.address_family;
 292         hints.ai_socktype = SOCK_STREAM;
 293         hints.ai_flags = AI_NUMERICHOST|AI_NUMERICSERV;
 294         if ((gaierr = getaddrinfo(name, strport, &hints, &res)) != 0) {
 295                 debug2("%s: could not resolve name %.100s as address: %s",
 296                     __func__, name, ssh_gai_strerror(gaierr));
 297                 return NULL;
 298         }
 299         if (res == NULL) {
 300                 debug("%s: getaddrinfo %.100s returned no addresses",
 301                  __func__, name);
 302                 return NULL;
 303         }
 304         if (res->ai_next != NULL) {
 305                 debug("%s: getaddrinfo %.100s returned multiple addresses",
 306                     __func__, name);
 307                 goto fail;
 308         }
 309         if ((gaierr = getnameinfo(res->ai_addr, res->ai_addrlen,
 310             addr, sizeof(addr), NULL, 0, NI_NUMERICHOST)) != 0) {
 311                 debug("%s: Could not format address for name %.100s: %s",
 312                     __func__, name, ssh_gai_strerror(gaierr));
 313                 goto fail;
 314         }
 315         if (strlcpy(caddr, addr, clen) >= clen) {
 316                 error("%s: host \"%s\" addr \"%s\" too long (max %lu)",
 317                     __func__, name,  addr, (u_long)clen);
 318                 if (clen > 0)
 319                         *caddr = '\0';
 320  fail:
 321                 freeaddrinfo(res);
 322                 return NULL;
 323         }
 324         return res;
 325 }
 326
 327 /*
 328  * Check whether the cname is a permitted replacement for the hostname
 329  * and perform the replacement if it is.
 330  * NB. this function must operate with a options having undefined members.
 331  */
 332 static int
 333 check_follow_cname(int direct, char **namep, const char *cname)
 334 {
 335         int i;
 336         struct allowed_cname *rule;
 337
 338         if (*cname == '\0' || options.num_permitted_cnames == 0 ||
 339             strcmp(*namep, cname) == 0)
 340                 return 0;
 341         if (options.canonicalize_hostname == SSH_CANONICALISE_NO)
 342                 return 0;
 343         /*
 344          * Don't attempt to canonicalize names that will be interpreted by
 345          * a proxy or jump host unless the user specifically requests so.
 346          */
 347         if (!direct &&
 348             options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS)
 349                 return 0;
 350         debug3("%s: check \"%s\" CNAME \"%s\"", __func__, *namep, cname);
 351         for (i = 0; i < options.num_permitted_cnames; i++) {
 352                 rule = options.permitted_cnames + i;
 353                 if (match_pattern_list(*namep, rule->source_list, 1) != 1 ||
 354                     match_pattern_list(cname, rule->target_list, 1) != 1)
 355                         continue;
 356                 verbose("Canonicalized DNS aliased hostname "
 357                     "\"%s\" => \"%s\"", *namep, cname);
 358                 free(*namep);
 359                 *namep = xstrdup(cname);
 360                 return 1;
 361         }
 362         return 0;
 363 }
 364
 365 /*
 366  * Attempt to resolve the supplied hostname after applying the user's
 367  * canonicalization rules. Returns the address list for the host or NULL
 368  * if no name was found after canonicalization.
 369  * NB. this function must operate with a options having undefined members.
 370  */
 371 static struct addrinfo *
 372 resolve_canonicalize(char **hostp, int port)
 373 {
 374         int i, direct, ndots;
 375         char *cp, *fullhost, newname[NI_MAXHOST];
 376         struct addrinfo *addrs;
 377
 378         if (options.canonicalize_hostname == SSH_CANONICALISE_NO)
 379                 return NULL;
 380
 381         /*
 382          * Don't attempt to canonicalize names that will be interpreted by
 383          * a proxy unless the user specifically requests so.
 384          */
 385         direct = option_clear_or_none(options.proxy_command) &&
 386             options.jump_host == NULL;
 387         if (!direct &&
 388             options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS)
 389                 return NULL;
 390
 391         /* Try numeric hostnames first */
 392         if ((addrs = resolve_addr(*hostp, port,
 393             newname, sizeof(newname))) != NULL) {
 394                 debug2("%s: hostname %.100s is address", __func__, *hostp);
 395                 if (strcasecmp(*hostp, newname) != 0) {
 396                         debug2("%s: canonicalised address \"%s\" => \"%s\"",
 397                             __func__, *hostp, newname);
 398                         free(*hostp);
 399                         *hostp = xstrdup(newname);
 400                 }
 401                 return addrs;
 402         }
 403
 404         /* If domain name is anchored, then resolve it now */
 405         if ((*hostp)[strlen(*hostp) - 1] == '.') {
 406                 debug3("%s: name is fully qualified", __func__);
 407                 fullhost = xstrdup(*hostp);
 408                 if ((addrs = resolve_host(fullhost, port, 0,
 409                     newname, sizeof(newname))) != NULL)
 410                         goto found;
 411                 free(fullhost);
 412                 goto notfound;
 413         }
 414
 415         /* Don't apply canonicalization to sufficiently-qualified hostnames */
 416         ndots = 0;
 417         for (cp = *hostp; *cp != '\0'; cp++) {
 418                 if (*cp == '.')
 419                         ndots++;
 420         }
 421         if (ndots > options.canonicalize_max_dots) {
 422                 debug3("%s: not canonicalizing hostname \"%s\" (max dots %d)",
 423                     __func__, *hostp, options.canonicalize_max_dots);
 424                 return NULL;
 425         }
 426         /* Attempt each supplied suffix */
 427         for (i = 0; i < options.num_canonical_domains; i++) {
 428                 *newname = '\0';
 429                 xasprintf(&fullhost, "%s.%s.", *hostp,
 430                     options.canonical_domains[i]);
 431                 debug3("%s: attempting \"%s\" => \"%s\"", __func__,
 432                     *hostp, fullhost);
 433                 if ((addrs = resolve_host(fullhost, port, 0,
 434                     newname, sizeof(newname))) == NULL) {
 435                         free(fullhost);
 436                         continue;
 437                 }
 438  found:
 439                 /* Remove trailing '.' */
 440                 fullhost[strlen(fullhost) - 1] = '\0';
 441                 /* Follow CNAME if requested */
 442                 if (!check_follow_cname(direct, &fullhost, newname)) {
 443                         debug("Canonicalized hostname \"%s\" => \"%s\"",
 444                             *hostp, fullhost);
 445                 }
 446                 free(*hostp);
 447                 *hostp = fullhost;
 448                 return addrs;
 449         }
 450  notfound:
 451         if (!options.canonicalize_fallback_local)
 452                 fatal("%s: Could not resolve host \"%s\"", __progname, *hostp);
 453         debug2("%s: host %s not found in any suffix", __func__, *hostp);
 454         return NULL;
 455 }
 456
 457 /*
 458  * Read per-user configuration file.  Ignore the system wide config
 459  * file if the user specifies a config file on the command line.
 460  */
 461 static void
 462 process_config_files(const char *host_arg, struct passwd *pw, int post_canon)
 463 {
 464         char buf[PATH_MAX];
 465         int r;
 466
 467         if (config != NULL) {
 468                 if (strcasecmp(config, "none") != 0 &&
 469                     !read_config_file(config, pw, host, host_arg, &options,
 470                     SSHCONF_USERCONF | (post_canon ? SSHCONF_POSTCANON : 0)))
 471                         fatal("Can't open user config file %.100s: "
 472                             "%.100s", config, strerror(errno));
 473         } else {
 474                 r = snprintf(buf, sizeof buf, "%s/%s", pw->pw_dir,
 475                     _PATH_SSH_USER_CONFFILE);
 476                 if (r > 0 && (size_t)r < sizeof(buf))
 477                         (void)read_config_file(buf, pw, host, host_arg,
 478                             &options, SSHCONF_CHECKPERM | SSHCONF_USERCONF |
 479                             (post_canon ? SSHCONF_POSTCANON : 0));
 480
 481                 /* Read systemwide configuration file after user config. */
 482                 (void)read_config_file(_PATH_HOST_CONFIG_FILE, pw,
 483                     host, host_arg, &options,
 484                     post_canon ? SSHCONF_POSTCANON : 0);
 485         }
 486 }
 487
 488 /* Rewrite the port number in an addrinfo list of addresses */
 489 static void
 490 set_addrinfo_port(struct addrinfo *addrs, int port)
 491 {
 492         struct addrinfo *addr;
 493
 494         for (addr = addrs; addr != NULL; addr = addr->ai_next) {
 495                 switch (addr->ai_family) {
 496                 case AF_INET:
 497                         ((struct sockaddr_in *)addr->ai_addr)->
 498                             sin_port = htons(port);
 499                         break;
 500                 case AF_INET6:
 501                         ((struct sockaddr_in6 *)addr->ai_addr)->
 502                             sin6_port = htons(port);
 503                         break;
 504                 }
 505         }
 506 }
 507
 508 /*
 509  * Main program for the ssh client.
 510  */
 511 int
 512 main(int ac, char **av)
 513 {
 514         struct ssh *ssh = NULL;
 515         int i, r, opt, exit_status, use_syslog, direct, config_test = 0;
 516         char *p, *cp, *line, *argv0, buf[PATH_MAX], *host_arg, *logfile;
 517         char thishost[NI_MAXHOST], shorthost[NI_MAXHOST], portstr[NI_MAXSERV];
 518         char cname[NI_MAXHOST], uidstr[32], *conn_hash_hex;
 519         struct stat st;
 520         struct passwd *pw;
 521         int timeout_ms;
 522         extern int optind, optreset;
 523         extern char *optarg;
 524         struct Forward fwd;
 525         struct addrinfo *addrs = NULL;
 526         struct ssh_digest_ctx *md;
 527         u_char conn_hash[SSH_DIGEST_MAX_LENGTH];
 528
 529         ssh_malloc_init();      /* must be called before any mallocs */
 530         /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
 531         sanitise_stdfd();
 532
 533         __progname = ssh_get_progname(av[0]);
 534
 535 #ifndef HAVE_SETPROCTITLE
 536         /* Prepare for later setproctitle emulation */
 537         /* Save argv so it isn't clobbered by setproctitle() emulation */
 538         saved_av = xcalloc(ac + 1, sizeof(*saved_av));
 539         for (i = 0; i < ac; i++)
 540                 saved_av[i] = xstrdup(av[i]);
 541         saved_av[i] = NULL;
 542         compat_init_setproctitle(ac, av);
 543         av = saved_av;
 544 #endif
 545
 546         /*
 547          * Discard other fds that are hanging around. These can cause problem
 548          * with backgrounded ssh processes started by ControlPersist.
 549          */
 550         closefrom(STDERR_FILENO + 1);
 551
 552         /*
 553          * Save the original real uid.  It will be needed later (uid-swapping
 554          * may clobber the real uid).
 555          */
 556         original_real_uid = getuid();
 557         original_effective_uid = geteuid();
 558
 559         /*
 560          * Use uid-swapping to give up root privileges for the duration of
 561          * option processing.  We will re-instantiate the rights when we are
 562          * ready to create the privileged port, and will permanently drop
 563          * them when the port has been created (actually, when the connection
 564          * has been made, as we may need to create the port several times).
 565          */
 566         PRIV_END;
 567
 568 #ifdef HAVE_SETRLIMIT
 569         /* If we are installed setuid root be careful to not drop core. */
 570         if (original_real_uid != original_effective_uid) {
 571                 struct rlimit rlim;
 572                 rlim.rlim_cur = rlim.rlim_max = 0;
 573                 if (setrlimit(RLIMIT_CORE, &rlim) < 0)
 574                         fatal("setrlimit failed: %.100s", strerror(errno));
 575         }
 576 #endif
 577         /* Get user data. */
 578         pw = getpwuid(original_real_uid);
 579         if (!pw) {
 580                 logit("No user exists for uid %lu", (u_long)original_real_uid);
 581                 exit(255);
 582         }
 583         /* Take a copy of the returned structure. */
 584         pw = pwcopy(pw);
 585
 586         /*
 587          * Set our umask to something reasonable, as some files are created
 588          * with the default umask.  This will make them world-readable but
 589          * writable only by the owner, which is ok for all files for which we
 590          * don't set the modes explicitly.
 591          */
 592         umask(022);
 593
 594         msetlocale();
 595
 596         /*
 597          * Initialize option structure to indicate that no values have been
 598          * set.
 599          */
 600         initialize_options(&options);
 601
 602         /* Parse command-line arguments. */
 603         host = NULL;
 604         use_syslog = 0;
 605         logfile = NULL;
 606         argv0 = av[0];
 607
 608  again:
 609         while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx"
 610             "ACD:E:F:GI:J:KL:MNO:PQ:R:S:TVw:W:XYy")) != -1) {
 611                 switch (opt) {
 612                 case '1':
 613                         options.protocol = SSH_PROTO_1;
 614                         break;
 615                 case '2':
 616                         options.protocol = SSH_PROTO_2;
 617                         break;
 618                 case '4':
 619                         options.address_family = AF_INET;
 620                         break;
 621                 case '6':
 622                         options.address_family = AF_INET6;
 623                         break;
 624                 case 'n':
 625                         stdin_null_flag = 1;
 626                         break;
 627                 case 'f':
 628                         fork_after_authentication_flag = 1;
 629                         stdin_null_flag = 1;
 630                         break;
 631                 case 'x':
 632                         options.forward_x11 = 0;
 633                         break;
 634                 case 'X':
 635                         options.forward_x11 = 1;
 636                         break;
 637                 case 'y':
 638                         use_syslog = 1;
 639                         break;
 640                 case 'E':
 641                         logfile = optarg;
 642                         break;
 643                 case 'G':
 644                         config_test = 1;
 645                         break;
 646                 case 'Y':
 647                         options.forward_x11 = 1;
 648                         options.forward_x11_trusted = 1;
 649                         break;
 650                 case 'g':
 651                         options.fwd_opts.gateway_ports = 1;
 652                         break;
 653                 case 'O':
 654                         if (options.stdio_forward_host != NULL)
 655                                 fatal("Cannot specify multiplexing "
 656                                     "command with -W");
 657                         else if (muxclient_command != 0)
 658                                 fatal("Multiplexing command already specified");
 659                         if (strcmp(optarg, "check") == 0)
 660                                 muxclient_command = SSHMUX_COMMAND_ALIVE_CHECK;
 661                         else if (strcmp(optarg, "forward") == 0)
 662                                 muxclient_command = SSHMUX_COMMAND_FORWARD;
 663                         else if (strcmp(optarg, "exit") == 0)
 664                                 muxclient_command = SSHMUX_COMMAND_TERMINATE;
 665                         else if (strcmp(optarg, "stop") == 0)
 666                                 muxclient_command = SSHMUX_COMMAND_STOP;
 667                         else if (strcmp(optarg, "cancel") == 0)
 668                                 muxclient_command = SSHMUX_COMMAND_CANCEL_FWD;
 669                         else if (strcmp(optarg, "proxy") == 0)
 670                                 muxclient_command = SSHMUX_COMMAND_PROXY;
 671                         else
 672                                 fatal("Invalid multiplex command.");
 673                         break;
 674                 case 'P':       /* deprecated */
 675                         options.use_privileged_port = 0;
 676                         break;
 677                 case 'Q':
 678                         cp = NULL;
 679                         if (strcmp(optarg, "cipher") == 0)
 680                                 cp = cipher_alg_list('\n', 0);
 681                         else if (strcmp(optarg, "cipher-auth") == 0)
 682                                 cp = cipher_alg_list('\n', 1);
 683                         else if (strcmp(optarg, "mac") == 0)
 684                                 cp = mac_alg_list('\n');
 685                         else if (strcmp(optarg, "kex") == 0)
 686                                 cp = kex_alg_list('\n');
 687                         else if (strcmp(optarg, "key") == 0)
 688                                 cp = sshkey_alg_list(0, 0, 0, '\n');
 689                         else if (strcmp(optarg, "key-cert") == 0)
 690                                 cp = sshkey_alg_list(1, 0, 0, '\n');
 691                         else if (strcmp(optarg, "key-plain") == 0)
 692                                 cp = sshkey_alg_list(0, 1, 0, '\n');
 693                         else if (strcmp(optarg, "protocol-version") == 0) {
 694 #ifdef WITH_SSH1
 695                                 cp = xstrdup("1\n2");
 696 #else
 697                                 cp = xstrdup("2");
 698 #endif
 699                         }
 700                         if (cp == NULL)
 701                                 fatal("Unsupported query \"%s\"", optarg);
 702                         printf("%s\n", cp);
 703                         free(cp);
 704                         exit(0);
 705                         break;
 706                 case 'a':
 707                         options.forward_agent = 0;
 708                         break;
 709                 case 'A':
 710                         options.forward_agent = 1;
 711                         break;
 712                 case 'k':
 713                         options.gss_deleg_creds = 0;
 714                         break;
 715                 case 'K':
 716                         options.gss_authentication = 1;
 717                         options.gss_deleg_creds = 1;
 718                         break;
 719                 case 'i':
 720                         p = tilde_expand_filename(optarg, original_real_uid);
 721                         if (stat(p, &st) < 0)
 722                                 fprintf(stderr, "Warning: Identity file %s "
 723                                     "not accessible: %s.\n", p,
 724                                     strerror(errno));
 725                         else
 726                                 add_identity_file(&options, NULL, p, 1);
 727                         free(p);
 728                         break;
 729                 case 'I':
 730 #ifdef ENABLE_PKCS11
 731                         free(options.pkcs11_provider);
 732                         options.pkcs11_provider = xstrdup(optarg);
 733 #else
 734                         fprintf(stderr, "no support for PKCS#11.\n");
 735 #endif
 736                         break;
 737                 case 'J':
 738                         if (options.jump_host != NULL)
 739                                 fatal("Only a single -J option permitted");
 740                         if (options.proxy_command != NULL)
 741                                 fatal("Cannot specify -J with ProxyCommand");
 742                         if (parse_jump(optarg, &options, 1) == -1)
 743                                 fatal("Invalid -J argument");
 744                         options.proxy_command = xstrdup("none");
 745                         break;
 746                 case 't':
 747                         if (options.request_tty == REQUEST_TTY_YES)
 748                                 options.request_tty = REQUEST_TTY_FORCE;
 749                         else
 750                                 options.request_tty = REQUEST_TTY_YES;
 751                         break;
 752                 case 'v':
 753                         if (debug_flag == 0) {
 754                                 debug_flag = 1;
 755                                 options.log_level = SYSLOG_LEVEL_DEBUG1;
 756                         } else {
 757                                 if (options.log_level < SYSLOG_LEVEL_DEBUG3) {
 758                                         debug_flag++;
 759                                         options.log_level++;
 760                                 }
 761                         }
 762                         break;
 763                 case 'V':
 764                         if (options.version_addendum &&
 765                             *options.version_addendum != '\0')
 766                                 fprintf(stderr, "%s %s, %s\n", SSH_RELEASE,
 767                                     options.version_addendum,
 768                                     OPENSSL_VERSION_STRING);
 769                         else
 770                                 fprintf(stderr, "%s, %s\n", SSH_RELEASE,
 771                                     OPENSSL_VERSION_STRING);
 772                         if (opt == 'V')
 773                                 exit(0);
 774                         break;
 775                 case 'w':
 776                         if (options.tun_open == -1)
 777                                 options.tun_open = SSH_TUNMODE_DEFAULT;
 778                         options.tun_local = a2tun(optarg, &options.tun_remote);
 779                         if (options.tun_local == SSH_TUNID_ERR) {
 780                                 fprintf(stderr,
 781                                     "Bad tun device '%s'\n", optarg);
 782                                 exit(255);
 783                         }
 784                         break;
 785                 case 'W':
 786                         if (options.stdio_forward_host != NULL)
 787                                 fatal("stdio forward already specified");
 788                         if (muxclient_command != 0)
 789                                 fatal("Cannot specify stdio forward with -O");
 790                         if (parse_forward(&fwd, optarg, 1, 0)) {
 791                                 options.stdio_forward_host = fwd.listen_host;
 792                                 options.stdio_forward_port = fwd.listen_port;
 793                                 free(fwd.connect_host);
 794                         } else {
 795                                 fprintf(stderr,
 796                                     "Bad stdio forwarding specification '%s'\n",
 797                                     optarg);
 798                                 exit(255);
 799                         }
 800                         options.request_tty = REQUEST_TTY_NO;
 801                         no_shell_flag = 1;
 802                         break;
 803                 case 'q':
 804                         options.log_level = SYSLOG_LEVEL_QUIET;
 805                         break;
 806                 case 'e':
 807                         if (optarg[0] == '^' && optarg[2] == 0 &&
 808                             (u_char) optarg[1] >= 64 &&
 809                             (u_char) optarg[1] < 128)
 810                                 options.escape_char = (u_char) optarg[1] & 31;
 811                         else if (strlen(optarg) == 1)
 812                                 options.escape_char = (u_char) optarg[0];
 813                         else if (strcmp(optarg, "none") == 0)
 814                                 options.escape_char = SSH_ESCAPECHAR_NONE;
 815                         else {
 816                                 fprintf(stderr, "Bad escape character '%s'.\n",
 817                                     optarg);
 818                                 exit(255);
 819                         }
 820                         break;
 821                 case 'c':
 822                         if (ciphers_valid(*optarg == '+' ?
 823                             optarg + 1 : optarg)) {
 824                                 /* SSH2 only */
 825                                 free(options.ciphers);
 826                                 options.ciphers = xstrdup(optarg);
 827                                 options.cipher = SSH_CIPHER_INVALID;
 828                                 break;
 829                         }
 830                         /* SSH1 only */
 831                         options.cipher = cipher_number(optarg);
 832                         if (options.cipher == -1) {
 833                                 fprintf(stderr, "Unknown cipher type '%s'\n",
 834                                     optarg);
 835                                 exit(255);
 836                         }
 837                         if (options.cipher == SSH_CIPHER_3DES)
 838                                 options.ciphers = xstrdup("3des-cbc");
 839                         else if (options.cipher == SSH_CIPHER_BLOWFISH)
 840                                 options.ciphers = xstrdup("blowfish-cbc");
 841                         else
 842                                 options.ciphers = xstrdup(KEX_CLIENT_ENCRYPT);
 843                         break;
 844                 case 'm':
 845                         if (mac_valid(optarg)) {
 846                                 free(options.macs);
 847                                 options.macs = xstrdup(optarg);
 848                         } else {
 849                                 fprintf(stderr, "Unknown mac type '%s'\n",
 850                                     optarg);
 851                                 exit(255);
 852                         }
 853                         break;
 854                 case 'M':
 855                         if (options.control_master == SSHCTL_MASTER_YES)
 856                                 options.control_master = SSHCTL_MASTER_ASK;
 857                         else
 858                                 options.control_master = SSHCTL_MASTER_YES;
 859                         break;
 860                 case 'p':
 861                         options.port = a2port(optarg);
 862                         if (options.port <= 0) {
 863                                 fprintf(stderr, "Bad port '%s'\n", optarg);
 864                                 exit(255);
 865                         }
 866                         break;
 867                 case 'l':
 868                         options.user = optarg;
 869                         break;
 870
 871                 case 'L':
 872                         if (parse_forward(&fwd, optarg, 0, 0))
 873                                 add_local_forward(&options, &fwd);
 874                         else {
 875                                 fprintf(stderr,
 876                                     "Bad local forwarding specification '%s'\n",
 877                                     optarg);
 878                                 exit(255);
 879                         }
 880                         break;
 881
 882                 case 'R':
 883                         if (parse_forward(&fwd, optarg, 0, 1)) {
 884                                 add_remote_forward(&options, &fwd);
 885                         } else {
 886                                 fprintf(stderr,
 887                                     "Bad remote forwarding specification "
 888                                     "'%s'\n", optarg);
 889                                 exit(255);
 890                         }
 891                         break;
 892
 893                 case 'D':
 894                         if (parse_forward(&fwd, optarg, 1, 0)) {
 895                                 add_local_forward(&options, &fwd);
 896                         } else {
 897                                 fprintf(stderr,
 898                                     "Bad dynamic forwarding specification "
 899                                     "'%s'\n", optarg);
 900                                 exit(255);
 901                         }
 902                         break;
 903
 904                 case 'C':
 905                         options.compression = 1;
 906                         break;
 907                 case 'N':
 908                         no_shell_flag = 1;
 909                         options.request_tty = REQUEST_TTY_NO;
 910                         break;
 911                 case 'T':
 912                         options.request_tty = REQUEST_TTY_NO;
 913                         break;
 914                 case 'o':
 915                         line = xstrdup(optarg);
 916                         if (process_config_line(&options, pw,
 917                             host ? host : "", host ? host : "", line,
 918                             "command-line", 0, NULL, SSHCONF_USERCONF) != 0)
 919                                 exit(255);
 920                         free(line);
 921                         break;
 922                 case 's':
 923                         subsystem_flag = 1;
 924                         break;
 925                 case 'S':
 926                         free(options.control_path);
 927                         options.control_path = xstrdup(optarg);
 928                         break;
 929                 case 'b':
 930                         options.bind_address = optarg;
 931                         break;
 932                 case 'F':
 933                         config = optarg;
 934                         break;
 935                 default:
 936                         usage();
 937                 }
 938         }
 939
 940         ac -= optind;
 941         av += optind;
 942
 943         if (ac > 0 && !host) {
 944                 if (strrchr(*av, '@')) {
 945                         p = xstrdup(*av);
 946                         cp = strrchr(p, '@');
 947                         if (cp == NULL || cp == p)
 948                                 usage();
 949                         options.user = p;
 950                         *cp = '\0';
 951                         host = xstrdup(++cp);
 952                 } else
 953                         host = xstrdup(*av);
 954                 if (ac > 1) {
 955                         optind = optreset = 1;
 956                         goto again;
 957                 }
 958                 ac--, av++;
 959         }
 960
 961         /* Check that we got a host name. */
 962         if (!host)
 963                 usage();
 964
 965         host_arg = xstrdup(host);
 966
 967 #ifdef WITH_OPENSSL
 968         OpenSSL_add_all_algorithms();
 969         ERR_load_crypto_strings();
 970 #endif
 971
 972         /* Initialize the command to execute on remote host. */
 973         buffer_init(&command);
 974
 975         /*
 976          * Save the command to execute on the remote host in a buffer. There
 977          * is no limit on the length of the command, except by the maximum
 978          * packet size.  Also sets the tty flag if there is no command.
 979          */
 980         if (!ac) {
 981                 /* No command specified - execute shell on a tty. */
 982                 if (subsystem_flag) {
 983                         fprintf(stderr,
 984                             "You must specify a subsystem to invoke.\n");
 985                         usage();
 986                 }
 987         } else {
 988                 /* A command has been specified.  Store it into the buffer. */
 989                 for (i = 0; i < ac; i++) {
 990                         if (i)
 991                                 buffer_append(&command, " ", 1);
 992                         buffer_append(&command, av[i], strlen(av[i]));
 993                 }
 994         }
 995
 996         /* Cannot fork to background if no command. */
 997         if (fork_after_authentication_flag && buffer_len(&command) == 0 &&
 998             !no_shell_flag)
 999                 fatal("Cannot fork into background without a command "
1000                     "to execute.");
1001
1002         /*
1003          * Initialize "log" output.  Since we are the client all output
1004          * goes to stderr unless otherwise specified by -y or -E.
1005          */
1006         if (use_syslog && logfile != NULL)
1007                 fatal("Can't specify both -y and -E");
1008         if (logfile != NULL)
1009                 log_redirect_stderr_to(logfile);
1010         log_init(argv0,
1011             options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level,
1012             SYSLOG_FACILITY_USER, !use_syslog);
1013
1014         if (debug_flag)
1015                 /* version_addendum is always NULL at this point */
1016                 logit("%s, %s", SSH_RELEASE, OPENSSL_VERSION_STRING);
1017
1018         /* Parse the configuration files */
1019         process_config_files(host_arg, pw, 0);
1020
1021         /* Hostname canonicalisation needs a few options filled. */
1022         fill_default_options_for_canonicalization(&options);
1023
1024         /* If the user has replaced the hostname then take it into use now */
1025         if (options.hostname != NULL) {
1026                 /* NB. Please keep in sync with readconf.c:match_cfg_line() */
1027                 cp = percent_expand(options.hostname,
1028                     "h", host, (char *)NULL);
1029                 free(host);
1030                 host = cp;
1031                 free(options.hostname);
1032                 options.hostname = xstrdup(host);
1033         }
1034
1035         /* If canonicalization requested then try to apply it */
1036         lowercase(host);
1037         if (options.canonicalize_hostname != SSH_CANONICALISE_NO)
1038                 addrs = resolve_canonicalize(&host, options.port);
1039
1040         /*
1041          * If CanonicalizePermittedCNAMEs have been specified but
1042          * other canonicalization did not happen (by not being requested
1043          * or by failing with fallback) then the hostname may still be changed
1044          * as a result of CNAME following.
1045          *
1046          * Try to resolve the bare hostname name using the system resolver's
1047          * usual search rules and then apply the CNAME follow rules.
1048          *
1049          * Skip the lookup if a ProxyCommand is being used unless the user
1050          * has specifically requested canonicalisation for this case via
1051          * CanonicalizeHostname=always
1052          */
1053         direct = option_clear_or_none(options.proxy_command) &&
1054             options.jump_host == NULL;
1055         if (addrs == NULL && options.num_permitted_cnames != 0 && (direct ||
1056             options.canonicalize_hostname == SSH_CANONICALISE_ALWAYS)) {
1057                 if ((addrs = resolve_host(host, options.port,
1058                     option_clear_or_none(options.proxy_command),
1059                     cname, sizeof(cname))) == NULL) {
1060                         /* Don't fatal proxied host names not in the DNS */
1061                         if (option_clear_or_none(options.proxy_command))
1062                                 cleanup_exit(255); /* logged in resolve_host */
1063                 } else
1064                         check_follow_cname(direct, &host, cname);
1065         }
1066
1067         /*
1068          * If canonicalisation is enabled then re-parse the configuration
1069          * files as new stanzas may match.
1070          */
1071         if (options.canonicalize_hostname != 0) {
1072                 debug("Re-reading configuration after hostname "
1073                     "canonicalisation");
1074                 free(options.hostname);
1075                 options.hostname = xstrdup(host);
1076                 process_config_files(host_arg, pw, 1);
1077                 /*
1078                  * Address resolution happens early with canonicalisation
1079                  * enabled and the port number may have changed since, so
1080                  * reset it in address list
1081                  */
1082                 if (addrs != NULL && options.port > 0)
1083                         set_addrinfo_port(addrs, options.port);
1084         }
1085
1086         /* Fill configuration defaults. */
1087         fill_default_options(&options);
1088
1089         /*
1090          * If ProxyJump option specified, then construct a ProxyCommand now.
1091          */
1092         if (options.jump_host != NULL) {
1093                 char port_s[8];
1094
1095                 /* Consistency check */
1096                 if (options.proxy_command != NULL)
1097                         fatal("inconsistent options: ProxyCommand+ProxyJump");
1098                 /* Never use FD passing for ProxyJump */
1099                 options.proxy_use_fdpass = 0;
1100                 snprintf(port_s, sizeof(port_s), "%d", options.jump_port);
1101                 xasprintf(&options.proxy_command,
1102                     "ssh%s%s%s%s%s%s%s%s%s%.*s -W '[%%h]:%%p' %s",
1103                     /* Optional "-l user" argument if jump_user set */
1104                     options.jump_user == NULL ? "" : " -l ",
1105                     options.jump_user == NULL ? "" : options.jump_user,
1106                     /* Optional "-p port" argument if jump_port set */
1107                     options.jump_port <= 0 ? "" : " -p ",
1108                     options.jump_port <= 0 ? "" : port_s,
1109                     /* Optional additional jump hosts ",..." */
1110                     options.jump_extra == NULL ? "" : " -J ",
1111                     options.jump_extra == NULL ? "" : options.jump_extra,
1112                     /* Optional "-F" argumment if -F specified */
1113                     config == NULL ? "" : " -F ",
1114                     config == NULL ? "" : config,
1115                     /* Optional "-v" arguments if -v set */
1116                     debug_flag ? " -" : "",
1117                     debug_flag, "vvv",
1118                     /* Mandatory hostname */
1119                     options.jump_host);
1120                 debug("Setting implicit ProxyCommand from ProxyJump: %s",
1121                     options.proxy_command);
1122         }
1123
1124         if (options.port == 0)
1125                 options.port = default_ssh_port();
1126         channel_set_af(options.address_family);
1127
1128         /* Tidy and check options */
1129         if (options.host_key_alias != NULL)
1130                 lowercase(options.host_key_alias);
1131         if (options.proxy_command != NULL &&
1132             strcmp(options.proxy_command, "-") == 0 &&
1133             options.proxy_use_fdpass)
1134                 fatal("ProxyCommand=- and ProxyUseFDPass are incompatible");
1135         if (options.control_persist &&
1136             options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK) {
1137                 debug("UpdateHostKeys=ask is incompatible with ControlPersist; "
1138                     "disabling");
1139                 options.update_hostkeys = 0;
1140         }
1141         if (options.connection_attempts <= 0)
1142                 fatal("Invalid number of ConnectionAttempts");
1143 #ifndef HAVE_CYGWIN
1144         if (original_effective_uid != 0)
1145                 options.use_privileged_port = 0;
1146 #endif
1147
1148         /* reinit */
1149         log_init(argv0, options.log_level, SYSLOG_FACILITY_USER, !use_syslog);
1150
1151         if (options.request_tty == REQUEST_TTY_YES ||
1152             options.request_tty == REQUEST_TTY_FORCE)
1153                 tty_flag = 1;
1154
1155         /* Allocate a tty by default if no command specified. */
1156         if (buffer_len(&command) == 0)
1157                 tty_flag = options.request_tty != REQUEST_TTY_NO;
1158
1159         /* Force no tty */
1160         if (options.request_tty == REQUEST_TTY_NO ||
1161             (muxclient_command && muxclient_command != SSHMUX_COMMAND_PROXY))
1162                 tty_flag = 0;
1163         /* Do not allocate a tty if stdin is not a tty. */
1164         if ((!isatty(fileno(stdin)) || stdin_null_flag) &&
1165             options.request_tty != REQUEST_TTY_FORCE) {
1166                 if (tty_flag)
1167                         logit("Pseudo-terminal will not be allocated because "
1168                             "stdin is not a terminal.");
1169                 tty_flag = 0;
1170         }
1171
1172         seed_rng();
1173
1174         if (options.user == NULL)
1175                 options.user = xstrdup(pw->pw_name);
1176
1177         if (gethostname(thishost, sizeof(thishost)) == -1)
1178                 fatal("gethostname: %s", strerror(errno));
1179         strlcpy(shorthost, thishost, sizeof(shorthost));
1180         shorthost[strcspn(thishost, ".")] = '\0';
1181         snprintf(portstr, sizeof(portstr), "%d", options.port);
1182         snprintf(uidstr, sizeof(uidstr), "%d", pw->pw_uid);
1183
1184         /* Find canonic host name. */
1185         if (strchr(host, '.') == 0) {
1186                 struct addrinfo hints;
1187                 struct addrinfo *ai = NULL;
1188                 int errgai;
1189                 memset(&hints, 0, sizeof(hints));
1190                 hints.ai_family = options.address_family;
1191                 hints.ai_flags = AI_CANONNAME;
1192                 hints.ai_socktype = SOCK_STREAM;
1193                 errgai = getaddrinfo(host, NULL, &hints, &ai);
1194                 if (errgai == 0) {
1195                         if (ai->ai_canonname != NULL)
1196                                 host = xstrdup(ai->ai_canonname);
1197                         freeaddrinfo(ai);
1198                 }
1199         }
1200
1201         if ((md = ssh_digest_start(SSH_DIGEST_SHA1)) == NULL ||
1202             ssh_digest_update(md, thishost, strlen(thishost)) < 0 ||
1203             ssh_digest_update(md, host, strlen(host)) < 0 ||
1204             ssh_digest_update(md, portstr, strlen(portstr)) < 0 ||
1205             ssh_digest_update(md, options.user, strlen(options.user)) < 0 ||
1206             ssh_digest_final(md, conn_hash, sizeof(conn_hash)) < 0)
1207                 fatal("%s: mux digest failed", __func__);
1208         ssh_digest_free(md);
1209         conn_hash_hex = tohex(conn_hash, ssh_digest_bytes(SSH_DIGEST_SHA1));
1210
1211         if (options.local_command != NULL) {
1212                 debug3("expanding LocalCommand: %s", options.local_command);
1213                 cp = options.local_command;
1214                 options.local_command = percent_expand(cp,
1215                     "C", conn_hash_hex,
1216                     "L", shorthost,
1217                     "d", pw->pw_dir,
1218                     "h", host,
1219                     "l", thishost,
1220                     "n", host_arg,
1221                     "p", portstr,
1222                     "r", options.user,
1223                     "u", pw->pw_name,
1224                     (char *)NULL);
1225                 debug3("expanded LocalCommand: %s", options.local_command);
1226                 free(cp);
1227         }
1228
1229         if (options.control_path != NULL) {
1230                 cp = tilde_expand_filename(options.control_path,
1231                     original_real_uid);
1232                 free(options.control_path);
1233                 options.control_path = percent_expand(cp,
1234                     "C", conn_hash_hex,
1235                     "L", shorthost,
1236                     "h", host,
1237                     "l", thishost,
1238                     "n", host_arg,
1239                     "p", portstr,
1240                     "r", options.user,
1241                     "u", pw->pw_name,
1242                     "i", uidstr,
1243                     (char *)NULL);
1244                 free(cp);
1245         }
1246         free(conn_hash_hex);
1247
1248         if (config_test) {
1249                 dump_client_config(&options, host);
1250                 exit(0);
1251         }
1252
1253         if (muxclient_command != 0 && options.control_path == NULL)
1254                 fatal("No ControlPath specified for \"-O\" command");
1255         if (options.control_path != NULL) {
1256                 int sock;
1257                 if ((sock = muxclient(options.control_path)) >= 0) {
1258                         packet_set_connection(sock, sock);
1259                         ssh = active_state; /* XXX */
1260                         enable_compat20();      /* XXX */
1261                         packet_set_mux();
1262                         goto skip_connect;
1263                 }
1264         }
1265
1266         /*
1267          * If hostname canonicalisation was not enabled, then we may not
1268          * have yet resolved the hostname. Do so now.
1269          */
1270         if (addrs == NULL && options.proxy_command == NULL) {
1271                 debug2("resolving \"%s\" port %d", host, options.port);
1272                 if ((addrs = resolve_host(host, options.port, 1,
1273                     cname, sizeof(cname))) == NULL)
1274                         cleanup_exit(255); /* resolve_host logs the error */
1275         }
1276
1277         timeout_ms = options.connection_timeout * 1000;
1278
1279         /* Open a connection to the remote host. */
1280         if (ssh_connect(host, addrs, &hostaddr, options.port,
1281             options.address_family, options.connection_attempts,
1282             &timeout_ms, options.tcp_keep_alive,
1283             options.use_privileged_port) != 0)
1284                 exit(255);
1285
1286         if (addrs != NULL)
1287                 freeaddrinfo(addrs);
1288
1289         packet_set_timeout(options.server_alive_interval,
1290             options.server_alive_count_max);
1291
1292         ssh = active_state; /* XXX */
1293
1294         if (timeout_ms > 0)
1295                 debug3("timeout: %d ms remain after connect", timeout_ms);
1296
1297         /*
1298          * If we successfully made the connection, load the host private key
1299          * in case we will need it later for combined rsa-rhosts
1300          * authentication. This must be done before releasing extra
1301          * privileges, because the file is only readable by root.
1302          * If we cannot access the private keys, load the public keys
1303          * instead and try to execute the ssh-keysign helper instead.
1304          */
1305         sensitive_data.nkeys = 0;
1306         sensitive_data.keys = NULL;
1307         sensitive_data.external_keysign = 0;
1308         if (options.rhosts_rsa_authentication ||
1309             options.hostbased_authentication) {
1310                 sensitive_data.nkeys = 9;
1311                 sensitive_data.keys = xcalloc(sensitive_data.nkeys,
1312                     sizeof(Key));
1313                 for (i = 0; i < sensitive_data.nkeys; i++)
1314                         sensitive_data.keys[i] = NULL;
1315
1316                 PRIV_START;
1317 #if WITH_SSH1
1318                 sensitive_data.keys[0] = key_load_private_type(KEY_RSA1,
1319                     _PATH_HOST_KEY_FILE, "", NULL, NULL);
1320 #endif
1321 #ifdef OPENSSL_HAS_ECC
1322                 sensitive_data.keys[1] = key_load_private_cert(KEY_ECDSA,
1323                     _PATH_HOST_ECDSA_KEY_FILE, "", NULL);
1324 #endif
1325                 sensitive_data.keys[2] = key_load_private_cert(KEY_ED25519,
1326                     _PATH_HOST_ED25519_KEY_FILE, "", NULL);
1327                 sensitive_data.keys[3] = key_load_private_cert(KEY_RSA,
1328                     _PATH_HOST_RSA_KEY_FILE, "", NULL);
1329                 sensitive_data.keys[4] = key_load_private_cert(KEY_DSA,
1330                     _PATH_HOST_DSA_KEY_FILE, "", NULL);
1331 #ifdef OPENSSL_HAS_ECC
1332                 sensitive_data.keys[5] = key_load_private_type(KEY_ECDSA,
1333                     _PATH_HOST_ECDSA_KEY_FILE, "", NULL, NULL);
1334 #endif
1335                 sensitive_data.keys[6] = key_load_private_type(KEY_ED25519,
1336                     _PATH_HOST_ED25519_KEY_FILE, "", NULL, NULL);
1337                 sensitive_data.keys[7] = key_load_private_type(KEY_RSA,
1338                     _PATH_HOST_RSA_KEY_FILE, "", NULL, NULL);
1339                 sensitive_data.keys[8] = key_load_private_type(KEY_DSA,
1340                     _PATH_HOST_DSA_KEY_FILE, "", NULL, NULL);
1341                 PRIV_END;
1342
1343                 if (options.hostbased_authentication == 1 &&
1344                     sensitive_data.keys[0] == NULL &&
1345                     sensitive_data.keys[5] == NULL &&
1346                     sensitive_data.keys[6] == NULL &&
1347                     sensitive_data.keys[7] == NULL &&
1348                     sensitive_data.keys[8] == NULL) {
1349 #ifdef OPENSSL_HAS_ECC
1350                         sensitive_data.keys[1] = key_load_cert(
1351                             _PATH_HOST_ECDSA_KEY_FILE);
1352 #endif
1353                         sensitive_data.keys[2] = key_load_cert(
1354                             _PATH_HOST_ED25519_KEY_FILE);
1355                         sensitive_data.keys[3] = key_load_cert(
1356                             _PATH_HOST_RSA_KEY_FILE);
1357                         sensitive_data.keys[4] = key_load_cert(
1358                             _PATH_HOST_DSA_KEY_FILE);
1359 #ifdef OPENSSL_HAS_ECC
1360                         sensitive_data.keys[5] = key_load_public(
1361                             _PATH_HOST_ECDSA_KEY_FILE, NULL);
1362 #endif
1363                         sensitive_data.keys[6] = key_load_public(
1364                             _PATH_HOST_ED25519_KEY_FILE, NULL);
1365                         sensitive_data.keys[7] = key_load_public(
1366                             _PATH_HOST_RSA_KEY_FILE, NULL);
1367                         sensitive_data.keys[8] = key_load_public(
1368                             _PATH_HOST_DSA_KEY_FILE, NULL);
1369                         sensitive_data.external_keysign = 1;
1370                 }
1371         }
1372         /*
1373          * Get rid of any extra privileges that we may have.  We will no
1374          * longer need them.  Also, extra privileges could make it very hard
1375          * to read identity files and other non-world-readable files from the
1376          * user's home directory if it happens to be on a NFS volume where
1377          * root is mapped to nobody.
1378          */
1379         if (original_effective_uid == 0) {
1380                 PRIV_START;
1381                 permanently_set_uid(pw);
1382         }
1383
1384         /*
1385          * Now that we are back to our own permissions, create ~/.ssh
1386          * directory if it doesn't already exist.
1387          */
1388         if (config == NULL) {
1389                 r = snprintf(buf, sizeof buf, "%s%s%s", pw->pw_dir,
1390                     strcmp(pw->pw_dir, "/") ? "/" : "", _PATH_SSH_USER_DIR);
1391                 if (r > 0 && (size_t)r < sizeof(buf) && stat(buf, &st) < 0) {
1392 #ifdef WITH_SELINUX
1393                         ssh_selinux_setfscreatecon(buf);
1394 #endif
1395                         if (mkdir(buf, 0700) < 0)
1396                                 error("Could not create directory '%.200s'.",
1397                                     buf);
1398 #ifdef WITH_SELINUX
1399                         ssh_selinux_setfscreatecon(NULL);
1400 #endif
1401                 }
1402         }
1403         /* load options.identity_files */
1404         load_public_identity_files();
1405
1406         /* optionally set the SSH_AUTHSOCKET_ENV_NAME varibale */
1407         if (options.identity_agent &&
1408             strcmp(options.identity_agent, SSH_AUTHSOCKET_ENV_NAME) != 0) {
1409                 if (strcmp(options.identity_agent, "none") == 0) {
1410                         unsetenv(SSH_AUTHSOCKET_ENV_NAME);
1411                 } else {
1412                         p = tilde_expand_filename(options.identity_agent,
1413                             original_real_uid);
1414                         cp = percent_expand(p, "d", pw->pw_dir,
1415                             "u", pw->pw_name, "l", thishost, "h", host,
1416                             "r", options.user, (char *)NULL);
1417                         setenv(SSH_AUTHSOCKET_ENV_NAME, cp, 1);
1418                         free(cp);
1419                         free(p);
1420                 }
1421         }
1422
1423         /* Expand ~ in known host file names. */
1424         tilde_expand_paths(options.system_hostfiles,
1425             options.num_system_hostfiles);
1426         tilde_expand_paths(options.user_hostfiles, options.num_user_hostfiles);
1427
1428         signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */
1429         signal(SIGCHLD, main_sigchld_handler);
1430
1431         /* Log into the remote system.  Never returns if the login fails. */
1432         ssh_login(&sensitive_data, host, (struct sockaddr *)&hostaddr,
1433             options.port, pw, timeout_ms);
1434
1435         if (packet_connection_is_on_socket()) {
1436                 verbose("Authenticated to %s ([%s]:%d).", host,
1437                     ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
1438         } else {
1439                 verbose("Authenticated to %s (via proxy).", host);
1440         }
1441
1442         /* We no longer need the private host keys.  Clear them now. */
1443         if (sensitive_data.nkeys != 0) {
1444                 for (i = 0; i < sensitive_data.nkeys; i++) {
1445                         if (sensitive_data.keys[i] != NULL) {
1446                                 /* Destroys contents safely */
1447                                 debug3("clear hostkey %d", i);
1448                                 key_free(sensitive_data.keys[i]);
1449                                 sensitive_data.keys[i] = NULL;
1450                         }
1451                 }
1452                 free(sensitive_data.keys);
1453         }
1454         for (i = 0; i < options.num_identity_files; i++) {
1455                 free(options.identity_files[i]);
1456                 options.identity_files[i] = NULL;
1457                 if (options.identity_keys[i]) {
1458                         key_free(options.identity_keys[i]);
1459                         options.identity_keys[i] = NULL;
1460                 }
1461         }
1462         for (i = 0; i < options.num_certificate_files; i++) {
1463                 free(options.certificate_files[i]);
1464                 options.certificate_files[i] = NULL;
1465         }
1466
1467  skip_connect:
1468         exit_status = compat20 ? ssh_session2() : ssh_session();
1469         packet_close();
1470
1471         if (options.control_path != NULL && muxserver_sock != -1)
1472                 unlink(options.control_path);
1473
1474         /* Kill ProxyCommand if it is running. */
1475         ssh_kill_proxy_command();
1476
1477         return exit_status;
1478 }
1479
1480 static void
1481 control_persist_detach(void)
1482 {
1483         pid_t pid;
1484         int devnull, keep_stderr;
1485
1486         debug("%s: backgrounding master process", __func__);
1487
1488         /*
1489          * master (current process) into the background, and make the
1490          * foreground process a client of the backgrounded master.
1491          */
1492         switch ((pid = fork())) {
1493         case -1:
1494                 fatal("%s: fork: %s", __func__, strerror(errno));
1495         case 0:
1496                 /* Child: master process continues mainloop */
1497                 break;
1498         default:
1499                 /* Parent: set up mux slave to connect to backgrounded master */
1500                 debug2("%s: background process is %ld", __func__, (long)pid);
1501                 stdin_null_flag = ostdin_null_flag;
1502                 options.request_tty = orequest_tty;
1503                 tty_flag = otty_flag;
1504                 close(muxserver_sock);
1505                 muxserver_sock = -1;
1506                 options.control_master = SSHCTL_MASTER_NO;
1507                 muxclient(options.control_path);
1508                 /* muxclient() doesn't return on success. */
1509                 fatal("Failed to connect to new control master");
1510         }
1511         if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1) {
1512                 error("%s: open(\"/dev/null\"): %s", __func__,
1513                     strerror(errno));
1514         } else {
1515                 keep_stderr = log_is_on_stderr() && debug_flag;
1516                 if (dup2(devnull, STDIN_FILENO) == -1 ||
1517                     dup2(devnull, STDOUT_FILENO) == -1 ||
1518                     (!keep_stderr && dup2(devnull, STDERR_FILENO) == -1))
1519                         error("%s: dup2: %s", __func__, strerror(errno));
1520                 if (devnull > STDERR_FILENO)
1521                         close(devnull);
1522         }
1523         daemon(1, 1);
1524         setproctitle("%s [mux]", options.control_path);
1525 }
1526
1527 /* Do fork() after authentication. Used by "ssh -f" */
1528 static void
1529 fork_postauth(void)
1530 {
1531         if (need_controlpersist_detach)
1532                 control_persist_detach();
1533         debug("forking to background");
1534         fork_after_authentication_flag = 0;
1535         if (daemon(1, 1) < 0)
1536                 fatal("daemon() failed: %.200s", strerror(errno));
1537 }
1538
1539 /* Callback for remote forward global requests */
1540 static void
1541 ssh_confirm_remote_forward(int type, u_int32_t seq, void *ctxt)
1542 {
1543         struct Forward *rfwd = (struct Forward *)ctxt;
1544
1545         /* XXX verbose() on failure? */
1546         debug("remote forward %s for: listen %s%s%d, connect %s:%d",
1547             type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure",
1548             rfwd->listen_path ? rfwd->listen_path :
1549             rfwd->listen_host ? rfwd->listen_host : "",
1550             (rfwd->listen_path || rfwd->listen_host) ? ":" : "",
1551             rfwd->listen_port, rfwd->connect_path ? rfwd->connect_path :
1552             rfwd->connect_host, rfwd->connect_port);
1553         if (rfwd->listen_path == NULL && rfwd->listen_port == 0) {
1554                 if (type == SSH2_MSG_REQUEST_SUCCESS) {
1555                         rfwd->allocated_port = packet_get_int();
1556                         logit("Allocated port %u for remote forward to %s:%d",
1557                             rfwd->allocated_port,
1558                             rfwd->connect_host, rfwd->connect_port);
1559                         channel_update_permitted_opens(rfwd->handle,
1560                             rfwd->allocated_port);
1561                 } else {
1562                         channel_update_permitted_opens(rfwd->handle, -1);
1563                 }
1564         }
1565
1566         if (type == SSH2_MSG_REQUEST_FAILURE) {
1567                 if (options.exit_on_forward_failure) {
1568                         if (rfwd->listen_path != NULL)
1569                                 fatal("Error: remote port forwarding failed "
1570                                     "for listen path %s", rfwd->listen_path);
1571                         else
1572                                 fatal("Error: remote port forwarding failed "
1573                                     "for listen port %d", rfwd->listen_port);
1574                 } else {
1575                         if (rfwd->listen_path != NULL)
1576                                 logit("Warning: remote port forwarding failed "
1577                                     "for listen path %s", rfwd->listen_path);
1578                         else
1579                                 logit("Warning: remote port forwarding failed "
1580                                     "for listen port %d", rfwd->listen_port);
1581                 }
1582         }
1583         if (++remote_forward_confirms_received == options.num_remote_forwards) {
1584                 debug("All remote forwarding requests processed");
1585                 if (fork_after_authentication_flag)
1586                         fork_postauth();
1587         }
1588 }
1589
1590 static void
1591 client_cleanup_stdio_fwd(int id, void *arg)
1592 {
1593         debug("stdio forwarding: done");
1594         cleanup_exit(0);
1595 }
1596
1597 static void
1598 ssh_stdio_confirm(int id, int success, void *arg)
1599 {
1600         if (!success)
1601                 fatal("stdio forwarding failed");
1602 }
1603
1604 static void
1605 ssh_init_stdio_forwarding(void)
1606 {
1607         Channel *c;
1608         int in, out;
1609
1610         if (options.stdio_forward_host == NULL)
1611                 return;
1612         if (!compat20)
1613                 fatal("stdio forwarding require Protocol 2");
1614
1615         debug3("%s: %s:%d", __func__, options.stdio_forward_host,
1616             options.stdio_forward_port);
1617
1618         if ((in = dup(STDIN_FILENO)) < 0 ||
1619             (out = dup(STDOUT_FILENO)) < 0)
1620                 fatal("channel_connect_stdio_fwd: dup() in/out failed");
1621         if ((c = channel_connect_stdio_fwd(options.stdio_forward_host,
1622             options.stdio_forward_port, in, out)) == NULL)
1623                 fatal("%s: channel_connect_stdio_fwd failed", __func__);
1624         channel_register_cleanup(c->self, client_cleanup_stdio_fwd, 0);
1625         channel_register_open_confirm(c->self, ssh_stdio_confirm, NULL);
1626 }
1627
1628 static void
1629 ssh_init_forwarding(void)
1630 {
1631         int success = 0;
1632         int i;
1633
1634         /* Initiate local TCP/IP port forwardings. */
1635         for (i = 0; i < options.num_local_forwards; i++) {
1636                 debug("Local connections to %.200s:%d forwarded to remote "
1637                     "address %.200s:%d",
1638                     (options.local_forwards[i].listen_path != NULL) ?
1639                     options.local_forwards[i].listen_path :
1640                     (options.local_forwards[i].listen_host == NULL) ?
1641                     (options.fwd_opts.gateway_ports ? "*" : "LOCALHOST") :
1642                     options.local_forwards[i].listen_host,
1643                     options.local_forwards[i].listen_port,
1644                     (options.local_forwards[i].connect_path != NULL) ?
1645                     options.local_forwards[i].connect_path :
1646                     options.local_forwards[i].connect_host,
1647                     options.local_forwards[i].connect_port);
1648                 success += channel_setup_local_fwd_listener(
1649                     &options.local_forwards[i], &options.fwd_opts);
1650         }
1651         if (i > 0 && success != i && options.exit_on_forward_failure)
1652                 fatal("Could not request local forwarding.");
1653         if (i > 0 && success == 0)
1654                 error("Could not request local forwarding.");
1655
1656         /* Initiate remote TCP/IP port forwardings. */
1657         for (i = 0; i < options.num_remote_forwards; i++) {
1658                 debug("Remote connections from %.200s:%d forwarded to "
1659                     "local address %.200s:%d",
1660                     (options.remote_forwards[i].listen_path != NULL) ?
1661                     options.remote_forwards[i].listen_path :
1662                     (options.remote_forwards[i].listen_host == NULL) ?
1663                     "LOCALHOST" : options.remote_forwards[i].listen_host,
1664                     options.remote_forwards[i].listen_port,
1665                     (options.remote_forwards[i].connect_path != NULL) ?
1666                     options.remote_forwards[i].connect_path :
1667                     options.remote_forwards[i].connect_host,
1668                     options.remote_forwards[i].connect_port);
1669                 options.remote_forwards[i].handle =
1670                     channel_request_remote_forwarding(
1671                     &options.remote_forwards[i]);
1672                 if (options.remote_forwards[i].handle < 0) {
1673                         if (options.exit_on_forward_failure)
1674                                 fatal("Could not request remote forwarding.");
1675                         else
1676                                 logit("Warning: Could not request remote "
1677                                     "forwarding.");
1678                 } else {
1679                         client_register_global_confirm(ssh_confirm_remote_forward,
1680                             &options.remote_forwards[i]);
1681                 }
1682         }
1683
1684         /* Initiate tunnel forwarding. */
1685         if (options.tun_open != SSH_TUNMODE_NO) {
1686                 if (client_request_tun_fwd(options.tun_open,
1687                     options.tun_local, options.tun_remote) == -1) {
1688                         if (options.exit_on_forward_failure)
1689                                 fatal("Could not request tunnel forwarding.");
1690                         else
1691                                 error("Could not request tunnel forwarding.");
1692                 }
1693         }
1694 }
1695
1696 static void
1697 check_agent_present(void)
1698 {
1699         int r;
1700
1701         if (options.forward_agent) {
1702                 /* Clear agent forwarding if we don't have an agent. */
1703                 if ((r = ssh_get_authentication_socket(NULL)) != 0) {
1704                         options.forward_agent = 0;
1705                         if (r != SSH_ERR_AGENT_NOT_PRESENT)
1706                                 debug("ssh_get_authentication_socket: %s",
1707                                     ssh_err(r));
1708                 }
1709         }
1710 }
1711
1712 static int
1713 ssh_session(void)
1714 {
1715         int type;
1716         int interactive = 0;
1717         int have_tty = 0;
1718         struct winsize ws;
1719         char *cp;
1720         const char *display;
1721         char *proto = NULL, *data = NULL;
1722
1723         /* Enable compression if requested. */
1724         if (options.compression) {
1725                 debug("Requesting compression at level %d.",
1726                     options.compression_level);
1727
1728                 if (options.compression_level < 1 ||
1729                     options.compression_level > 9)
1730                         fatal("Compression level must be from 1 (fast) to "
1731                             "9 (slow, best).");
1732
1733                 /* Send the request. */
1734                 packet_start(SSH_CMSG_REQUEST_COMPRESSION);
1735                 packet_put_int(options.compression_level);
1736                 packet_send();
1737                 packet_write_wait();
1738                 type = packet_read();
1739                 if (type == SSH_SMSG_SUCCESS)
1740                         packet_start_compression(options.compression_level);
1741                 else if (type == SSH_SMSG_FAILURE)
1742                         logit("Warning: Remote host refused compression.");
1743                 else
1744                         packet_disconnect("Protocol error waiting for "
1745                             "compression response.");
1746         }
1747         /* Allocate a pseudo tty if appropriate. */
1748         if (tty_flag) {
1749                 debug("Requesting pty.");
1750
1751                 /* Start the packet. */
1752                 packet_start(SSH_CMSG_REQUEST_PTY);
1753
1754                 /* Store TERM in the packet.  There is no limit on the
1755                    length of the string. */
1756                 cp = getenv("TERM");
1757                 if (!cp)
1758                         cp = "";
1759                 packet_put_cstring(cp);
1760
1761                 /* Store window size in the packet. */
1762                 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
1763                         memset(&ws, 0, sizeof(ws));
1764                 packet_put_int((u_int)ws.ws_row);
1765                 packet_put_int((u_int)ws.ws_col);
1766                 packet_put_int((u_int)ws.ws_xpixel);
1767                 packet_put_int((u_int)ws.ws_ypixel);
1768
1769                 /* Store tty modes in the packet. */
1770                 tty_make_modes(fileno(stdin), NULL);
1771
1772                 /* Send the packet, and wait for it to leave. */
1773                 packet_send();
1774                 packet_write_wait();
1775
1776                 /* Read response from the server. */
1777                 type = packet_read();
1778                 if (type == SSH_SMSG_SUCCESS) {
1779                         interactive = 1;
1780                         have_tty = 1;
1781                 } else if (type == SSH_SMSG_FAILURE)
1782                         logit("Warning: Remote host failed or refused to "
1783                             "allocate a pseudo tty.");
1784                 else
1785                         packet_disconnect("Protocol error waiting for pty "
1786                             "request response.");
1787         }
1788         /* Request X11 forwarding if enabled and DISPLAY is set. */
1789         display = getenv("DISPLAY");
1790         if (display == NULL && options.forward_x11)
1791                 debug("X11 forwarding requested but DISPLAY not set");
1792         if (options.forward_x11 && client_x11_get_proto(display,
1793             options.xauth_location, options.forward_x11_trusted,
1794             options.forward_x11_timeout, &proto, &data) == 0) {
1795                 /* Request forwarding with authentication spoofing. */
1796                 debug("Requesting X11 forwarding with authentication "
1797                     "spoofing.");
1798                 x11_request_forwarding_with_spoofing(0, display, proto,
1799                     data, 0);
1800                 /* Read response from the server. */
1801                 type = packet_read();
1802                 if (type == SSH_SMSG_SUCCESS) {
1803                         interactive = 1;
1804                 } else if (type == SSH_SMSG_FAILURE) {
1805                         logit("Warning: Remote host denied X11 forwarding.");
1806                 } else {
1807                         packet_disconnect("Protocol error waiting for X11 "
1808                             "forwarding");
1809                 }
1810         }
1811         /* Tell the packet module whether this is an interactive session. */
1812         packet_set_interactive(interactive,
1813             options.ip_qos_interactive, options.ip_qos_bulk);
1814
1815         /* Request authentication agent forwarding if appropriate. */
1816         check_agent_present();
1817
1818         if (options.forward_agent) {
1819                 debug("Requesting authentication agent forwarding.");
1820                 auth_request_forwarding();
1821
1822                 /* Read response from the server. */
1823                 type = packet_read();
1824                 packet_check_eom();
1825                 if (type != SSH_SMSG_SUCCESS)
1826                         logit("Warning: Remote host denied authentication agent forwarding.");
1827         }
1828
1829         /* Initiate port forwardings. */
1830         ssh_init_stdio_forwarding();
1831         ssh_init_forwarding();
1832
1833         /* Execute a local command */
1834         if (options.local_command != NULL &&
1835             options.permit_local_command)
1836                 ssh_local_cmd(options.local_command);
1837
1838         /*
1839          * If requested and we are not interested in replies to remote
1840          * forwarding requests, then let ssh continue in the background.
1841          */
1842         if (fork_after_authentication_flag) {
1843                 if (options.exit_on_forward_failure &&
1844                     options.num_remote_forwards > 0) {
1845                         debug("deferring postauth fork until remote forward "
1846                             "confirmation received");
1847                 } else
1848                         fork_postauth();
1849         }
1850
1851         /*
1852          * If a command was specified on the command line, execute the
1853          * command now. Otherwise request the server to start a shell.
1854          */
1855         if (buffer_len(&command) > 0) {
1856                 int len = buffer_len(&command);
1857                 if (len > 900)
1858                         len = 900;
1859                 debug("Sending command: %.*s", len,
1860                     (u_char *)buffer_ptr(&command));
1861                 packet_start(SSH_CMSG_EXEC_CMD);
1862                 packet_put_string(buffer_ptr(&command), buffer_len(&command));
1863                 packet_send();
1864                 packet_write_wait();
1865         } else {
1866                 debug("Requesting shell.");
1867                 packet_start(SSH_CMSG_EXEC_SHELL);
1868                 packet_send();
1869                 packet_write_wait();
1870         }
1871
1872         /* Enter the interactive session. */
1873         return client_loop(have_tty, tty_flag ?
1874             options.escape_char : SSH_ESCAPECHAR_NONE, 0);
1875 }
1876
1877 /* request pty/x11/agent/tcpfwd/shell for channel */
1878 static void
1879 ssh_session2_setup(int id, int success, void *arg)
1880 {
1881         extern char **environ;
1882         const char *display;
1883         int interactive = tty_flag;
1884         char *proto = NULL, *data = NULL;
1885
1886         if (!success)
1887                 return; /* No need for error message, channels code sens one */
1888
1889         display = getenv("DISPLAY");
1890         if (display == NULL && options.forward_x11)
1891                 debug("X11 forwarding requested but DISPLAY not set");
1892         if (options.forward_x11 && client_x11_get_proto(display,
1893             options.xauth_location, options.forward_x11_trusted,
1894             options.forward_x11_timeout, &proto, &data) == 0) {
1895                 /* Request forwarding with authentication spoofing. */
1896                 debug("Requesting X11 forwarding with authentication "
1897                     "spoofing.");
1898                 x11_request_forwarding_with_spoofing(id, display, proto,
1899                     data, 1);
1900                 client_expect_confirm(id, "X11 forwarding", CONFIRM_WARN);
1901                 /* XXX exit_on_forward_failure */
1902                 interactive = 1;
1903         }
1904
1905         check_agent_present();
1906         if (options.forward_agent) {
1907                 debug("Requesting authentication agent forwarding.");
1908                 channel_request_start(id, "auth-agent-req@openssh.com", 0);
1909                 packet_send();
1910         }
1911
1912         /* Tell the packet module whether this is an interactive session. */
1913         packet_set_interactive(interactive,
1914             options.ip_qos_interactive, options.ip_qos_bulk);
1915
1916         client_session2_setup(id, tty_flag, subsystem_flag, getenv("TERM"),
1917             NULL, fileno(stdin), &command, environ);
1918 }
1919
1920 /* open new channel for a session */
1921 static int
1922 ssh_session2_open(void)
1923 {
1924         Channel *c;
1925         int window, packetmax, in, out, err;
1926
1927         if (stdin_null_flag) {
1928                 in = open(_PATH_DEVNULL, O_RDONLY);
1929         } else {
1930                 in = dup(STDIN_FILENO);
1931         }
1932         out = dup(STDOUT_FILENO);
1933         err = dup(STDERR_FILENO);
1934
1935         if (in < 0 || out < 0 || err < 0)
1936                 fatal("dup() in/out/err failed");
1937
1938         /* enable nonblocking unless tty */
1939         if (!isatty(in))
1940                 set_nonblock(in);
1941         if (!isatty(out))
1942                 set_nonblock(out);
1943         if (!isatty(err))
1944                 set_nonblock(err);
1945
1946         window = CHAN_SES_WINDOW_DEFAULT;
1947         packetmax = CHAN_SES_PACKET_DEFAULT;
1948         if (tty_flag) {
1949                 window >>= 1;
1950                 packetmax >>= 1;
1951         }
1952         c = channel_new(
1953             "session", SSH_CHANNEL_OPENING, in, out, err,
1954             window, packetmax, CHAN_EXTENDED_WRITE,
1955             "client-session", /*nonblock*/0);
1956
1957         debug3("ssh_session2_open: channel_new: %d", c->self);
1958
1959         channel_send_open(c->self);
1960         if (!no_shell_flag)
1961                 channel_register_open_confirm(c->self,
1962                     ssh_session2_setup, NULL);
1963
1964         return c->self;
1965 }
1966
1967 static int
1968 ssh_session2(void)
1969 {
1970         int id = -1;
1971
1972         /* XXX should be pre-session */
1973         if (!options.control_persist)
1974                 ssh_init_stdio_forwarding();
1975         ssh_init_forwarding();
1976
1977         /* Start listening for multiplex clients */
1978         if (!packet_get_mux())
1979                 muxserver_listen();
1980
1981         /*
1982          * If we are in control persist mode and have a working mux listen
1983          * socket, then prepare to background ourselves and have a foreground
1984          * client attach as a control slave.
1985          * NB. we must save copies of the flags that we override for
1986          * the backgrounding, since we defer attachment of the slave until
1987          * after the connection is fully established (in particular,
1988          * async rfwd replies have been received for ExitOnForwardFailure).
1989          */
1990         if (options.control_persist && muxserver_sock != -1) {
1991                 ostdin_null_flag = stdin_null_flag;
1992                 ono_shell_flag = no_shell_flag;
1993                 orequest_tty = options.request_tty;
1994                 otty_flag = tty_flag;
1995                 stdin_null_flag = 1;
1996                 no_shell_flag = 1;
1997                 tty_flag = 0;
1998                 if (!fork_after_authentication_flag)
1999                         need_controlpersist_detach = 1;
2000                 fork_after_authentication_flag = 1;
2001         }
2002         /*
2003          * ControlPersist mux listen socket setup failed, attempt the
2004          * stdio forward setup that we skipped earlier.
2005          */
2006         if (options.control_persist && muxserver_sock == -1)
2007                 ssh_init_stdio_forwarding();
2008
2009         if (!no_shell_flag || (datafellows & SSH_BUG_DUMMYCHAN))
2010                 id = ssh_session2_open();
2011         else {
2012                 packet_set_interactive(
2013                     options.control_master == SSHCTL_MASTER_NO,
2014                     options.ip_qos_interactive, options.ip_qos_bulk);
2015         }
2016
2017         /* If we don't expect to open a new session, then disallow it */
2018         if (options.control_master == SSHCTL_MASTER_NO &&
2019             (datafellows & SSH_NEW_OPENSSH)) {
2020                 debug("Requesting no-more-sessions@openssh.com");
2021                 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2022                 packet_put_cstring("no-more-sessions@openssh.com");
2023                 packet_put_char(0);
2024                 packet_send();
2025         }
2026
2027         /* Execute a local command */
2028         if (options.local_command != NULL &&
2029             options.permit_local_command)
2030                 ssh_local_cmd(options.local_command);
2031
2032         /*
2033          * If requested and we are not interested in replies to remote
2034          * forwarding requests, then let ssh continue in the background.
2035          */
2036         if (fork_after_authentication_flag) {
2037                 if (options.exit_on_forward_failure &&
2038                     options.num_remote_forwards > 0) {
2039                         debug("deferring postauth fork until remote forward "
2040                             "confirmation received");
2041                 } else
2042                         fork_postauth();
2043         }
2044
2045         return client_loop(tty_flag, tty_flag ?
2046             options.escape_char : SSH_ESCAPECHAR_NONE, id);
2047 }
2048
2049 /* Loads all IdentityFile and CertificateFile keys */
2050 static void
2051 load_public_identity_files(void)
2052 {
2053         char *filename, *cp, thishost[NI_MAXHOST];
2054         char *pwdir = NULL, *pwname = NULL;
2055         Key *public;
2056         struct passwd *pw;
2057         int i;
2058         u_int n_ids, n_certs;
2059         char *identity_files[SSH_MAX_IDENTITY_FILES];
2060         Key *identity_keys[SSH_MAX_IDENTITY_FILES];
2061         char *certificate_files[SSH_MAX_CERTIFICATE_FILES];
2062         struct sshkey *certificates[SSH_MAX_CERTIFICATE_FILES];
2063 #ifdef ENABLE_PKCS11
2064         Key **keys;
2065         int nkeys;
2066 #endif /* PKCS11 */
2067
2068         n_ids = n_certs = 0;
2069         memset(identity_files, 0, sizeof(identity_files));
2070         memset(identity_keys, 0, sizeof(identity_keys));
2071         memset(certificate_files, 0, sizeof(certificate_files));
2072         memset(certificates, 0, sizeof(certificates));
2073
2074 #ifdef ENABLE_PKCS11
2075         if (options.pkcs11_provider != NULL &&
2076             options.num_identity_files < SSH_MAX_IDENTITY_FILES &&
2077             (pkcs11_init(!options.batch_mode) == 0) &&
2078             (nkeys = pkcs11_add_provider(options.pkcs11_provider, NULL,
2079             &keys)) > 0) {
2080                 for (i = 0; i < nkeys; i++) {
2081                         if (n_ids >= SSH_MAX_IDENTITY_FILES) {
2082                                 key_free(keys[i]);
2083                                 continue;
2084                         }
2085                         identity_keys[n_ids] = keys[i];
2086                         identity_files[n_ids] =
2087                             xstrdup(options.pkcs11_provider); /* XXX */
2088                         n_ids++;
2089                 }
2090                 free(keys);
2091         }
2092 #endif /* ENABLE_PKCS11 */
2093         if ((pw = getpwuid(original_real_uid)) == NULL)
2094                 fatal("load_public_identity_files: getpwuid failed");
2095         pwname = xstrdup(pw->pw_name);
2096         pwdir = xstrdup(pw->pw_dir);
2097         if (gethostname(thishost, sizeof(thishost)) == -1)
2098                 fatal("load_public_identity_files: gethostname: %s",
2099                     strerror(errno));
2100         for (i = 0; i < options.num_identity_files; i++) {
2101                 if (n_ids >= SSH_MAX_IDENTITY_FILES ||
2102                     strcasecmp(options.identity_files[i], "none") == 0) {
2103                         free(options.identity_files[i]);
2104                         options.identity_files[i] = NULL;
2105                         continue;
2106                 }
2107                 cp = tilde_expand_filename(options.identity_files[i],
2108                     original_real_uid);
2109                 filename = percent_expand(cp, "d", pwdir,
2110                     "u", pwname, "l", thishost, "h", host,
2111                     "r", options.user, (char *)NULL);
2112                 free(cp);
2113                 public = key_load_public(filename, NULL);
2114                 debug("identity file %s type %d", filename,
2115                     public ? public->type : -1);
2116                 free(options.identity_files[i]);
2117                 identity_files[n_ids] = filename;
2118                 identity_keys[n_ids] = public;
2119
2120                 if (++n_ids >= SSH_MAX_IDENTITY_FILES)
2121                         continue;
2122
2123                 /*
2124                  * If no certificates have been explicitly listed then try
2125                  * to add the default certificate variant too.
2126                  */
2127                 if (options.num_certificate_files != 0)
2128                         continue;
2129                 xasprintf(&cp, "%s-cert", filename);
2130                 public = key_load_public(cp, NULL);
2131                 debug("identity file %s type %d", cp,
2132                     public ? public->type : -1);
2133                 if (public == NULL) {
2134                         free(cp);
2135                         continue;
2136                 }
2137                 if (!key_is_cert(public)) {
2138                         debug("%s: key %s type %s is not a certificate",
2139                             __func__, cp, key_type(public));
2140                         key_free(public);
2141                         free(cp);
2142                         continue;
2143                 }
2144                 /* NB. leave filename pointing to private key */
2145                 identity_files[n_ids] = xstrdup(filename);
2146                 identity_keys[n_ids] = public;
2147                 n_ids++;
2148         }
2149
2150         if (options.num_certificate_files > SSH_MAX_CERTIFICATE_FILES)
2151                 fatal("%s: too many certificates", __func__);
2152         for (i = 0; i < options.num_certificate_files; i++) {
2153                 cp = tilde_expand_filename(options.certificate_files[i],
2154                     original_real_uid);
2155                 filename = percent_expand(cp, "d", pwdir,
2156                     "u", pwname, "l", thishost, "h", host,
2157                     "r", options.user, (char *)NULL);
2158                 free(cp);
2159
2160                 public = key_load_public(filename, NULL);
2161                 debug("certificate file %s type %d", filename,
2162                     public ? public->type : -1);
2163                 free(options.certificate_files[i]);
2164                 options.certificate_files[i] = NULL;
2165                 if (public == NULL) {
2166                         free(filename);
2167                         continue;
2168                 }
2169                 if (!key_is_cert(public)) {
2170                         debug("%s: key %s type %s is not a certificate",
2171                             __func__, filename, key_type(public));
2172                         key_free(public);
2173                         free(filename);
2174                         continue;
2175                 }
2176                 certificate_files[n_certs] = filename;
2177                 certificates[n_certs] = public;
2178                 ++n_certs;
2179         }
2180
2181         options.num_identity_files = n_ids;
2182         memcpy(options.identity_files, identity_files, sizeof(identity_files));
2183         memcpy(options.identity_keys, identity_keys, sizeof(identity_keys));
2184
2185         options.num_certificate_files = n_certs;
2186         memcpy(options.certificate_files,
2187             certificate_files, sizeof(certificate_files));
2188         memcpy(options.certificates, certificates, sizeof(certificates));
2189
2190         explicit_bzero(pwname, strlen(pwname));
2191         free(pwname);
2192         explicit_bzero(pwdir, strlen(pwdir));
2193         free(pwdir);
2194 }
2195
2196 static void
2197 main_sigchld_handler(int sig)
2198 {
2199         int save_errno = errno;
2200         pid_t pid;
2201         int status;
2202
2203         while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
2204             (pid < 0 && errno == EINTR))
2205                 ;
2206
2207         signal(sig, main_sigchld_handler);
2208         errno = save_errno;
2209 }