crypto/openssh/ssh.c

   1 /* $OpenBSD: ssh.c,v 1.407 2014/07/17 07:22:19 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
  45 #include <sys/types.h>
  46 #ifdef HAVE_SYS_STAT_H
  47 # include <sys/stat.h>
  48 #endif
  49 #include <sys/resource.h>
  50 #include <sys/ioctl.h>
  51 #include <sys/param.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
  71 #include <netinet/in.h>
  72 #include <arpa/inet.h>
  73
  74 #ifdef WITH_OPENSSL
  75 #include <openssl/evp.h>
  76 #include <openssl/err.h>
  77 #endif
  78 #include "openbsd-compat/openssl-compat.h"
  79 #include "openbsd-compat/sys-queue.h"
  80
  81 #include "xmalloc.h"
  82 #include "ssh.h"
  83 #include "ssh1.h"
  84 #include "ssh2.h"
  85 #include "canohost.h"
  86 #include "compat.h"
  87 #include "cipher.h"
  88 #include "digest.h"
  89 #include "packet.h"
  90 #include "buffer.h"
  91 #include "channels.h"
  92 #include "key.h"
  93 #include "authfd.h"
  94 #include "authfile.h"
  95 #include "pathnames.h"
  96 #include "dispatch.h"
  97 #include "clientloop.h"
  98 #include "log.h"
  99 #include "misc.h"
 100 #include "readconf.h"
 101 #include "sshconnect.h"
 102 #include "kex.h"
 103 #include "mac.h"
 104 #include "sshpty.h"
 105 #include "match.h"
 106 #include "msg.h"
 107 #include "uidswap.h"
 108 #include "roaming.h"
 109 #include "version.h"
 110
 111 #ifdef ENABLE_PKCS11
 112 #include "ssh-pkcs11.h"
 113 #endif
 114
 115 extern char *__progname;
 116
 117 /* Saves a copy of argv for setproctitle emulation */
 118 #ifndef HAVE_SETPROCTITLE
 119 static char **saved_av;
 120 #endif
 121
 122 /* Flag indicating whether debug mode is on.  May be set on the command line. */
 123 int debug_flag = 0;
 124
 125 /* Flag indicating whether a tty should be requested */
 126 int tty_flag = 0;
 127
 128 /* don't exec a shell */
 129 int no_shell_flag = 0;
 130
 131 /*
 132  * Flag indicating that nothing should be read from stdin.  This can be set
 133  * on the command line.
 134  */
 135 int stdin_null_flag = 0;
 136
 137 /*
 138  * Flag indicating that the current process should be backgrounded and
 139  * a new slave launched in the foreground for ControlPersist.
 140  */
 141 int need_controlpersist_detach = 0;
 142
 143 /* Copies of flags for ControlPersist foreground slave */
 144 int ostdin_null_flag, ono_shell_flag, otty_flag, orequest_tty;
 145
 146 /*
 147  * Flag indicating that ssh should fork after authentication.  This is useful
 148  * so that the passphrase can be entered manually, and then ssh goes to the
 149  * background.
 150  */
 151 int fork_after_authentication_flag = 0;
 152
 153 /* forward stdio to remote host and port */
 154 char *stdio_forward_host = NULL;
 155 int stdio_forward_port = 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 [-1246AaCfgKkMNnqsTtVvXxYy] [-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 "           [-L [bind_address:]port:host:hostport] [-l login_name] [-m mac_spec]\n"
 206 "           [-O ctl_cmd] [-o option] [-p port]\n"
 207 "           [-Q cipher | cipher-auth | mac | kex | key]\n"
 208 "           [-R [bind_address:]port:host:hostport] [-S ctl_path] [-W host:port]\n"
 209 "           [-w local_tun[:remote_tun]] [user@]hostname [command]\n"
 210         );
 211         exit(255);
 212 }
 213
 214 static int ssh_session(void);
 215 static int ssh_session2(void);
 216 static void load_public_identity_files(void);
 217 static void main_sigchld_handler(int);
 218
 219 /* from muxclient.c */
 220 void muxclient(const char *);
 221 void muxserver_listen(void);
 222
 223 /* ~/ expand a list of paths. NB. assumes path[n] is heap-allocated. */
 224 static void
 225 tilde_expand_paths(char **paths, u_int num_paths)
 226 {
 227         u_int i;
 228         char *cp;
 229
 230         for (i = 0; i < num_paths; i++) {
 231                 cp = tilde_expand_filename(paths[i], original_real_uid);
 232                 free(paths[i]);
 233                 paths[i] = cp;
 234         }
 235 }
 236
 237 /*
 238  * Attempt to resolve a host name / port to a set of addresses and
 239  * optionally return any CNAMEs encountered along the way.
 240  * Returns NULL on failure.
 241  * NB. this function must operate with a options having undefined members.
 242  */
 243 static struct addrinfo *
 244 resolve_host(const char *name, int port, int logerr, char *cname, size_t clen)
 245 {
 246         char strport[NI_MAXSERV];
 247         struct addrinfo hints, *res;
 248         int gaierr, loglevel = SYSLOG_LEVEL_DEBUG1;
 249
 250         if (port <= 0)
 251                 port = default_ssh_port();
 252
 253         snprintf(strport, sizeof strport, "%u", port);
 254         memset(&hints, 0, sizeof(hints));
 255         hints.ai_family = options.address_family == -1 ?
 256             AF_UNSPEC : options.address_family;
 257         hints.ai_socktype = SOCK_STREAM;
 258         if (cname != NULL)
 259                 hints.ai_flags = AI_CANONNAME;
 260         if ((gaierr = getaddrinfo(name, strport, &hints, &res)) != 0) {
 261                 if (logerr || (gaierr != EAI_NONAME && gaierr != EAI_NODATA))
 262                         loglevel = SYSLOG_LEVEL_ERROR;
 263                 do_log2(loglevel, "%s: Could not resolve hostname %.100s: %s",
 264                     __progname, name, ssh_gai_strerror(gaierr));
 265                 return NULL;
 266         }
 267         if (cname != NULL && res->ai_canonname != NULL) {
 268                 if (strlcpy(cname, res->ai_canonname, clen) >= clen) {
 269                         error("%s: host \"%s\" cname \"%s\" too long (max %lu)",
 270                             __func__, name,  res->ai_canonname, (u_long)clen);
 271                         if (clen > 0)
 272                                 *cname = '\0';
 273                 }
 274         }
 275         return res;
 276 }
 277
 278 /*
 279  * Check whether the cname is a permitted replacement for the hostname
 280  * and perform the replacement if it is.
 281  * NB. this function must operate with a options having undefined members.
 282  */
 283 static int
 284 check_follow_cname(char **namep, const char *cname)
 285 {
 286         int i;
 287         struct allowed_cname *rule;
 288
 289         if (*cname == '\0' || options.num_permitted_cnames == 0 ||
 290             strcmp(*namep, cname) == 0)
 291                 return 0;
 292         if (options.canonicalize_hostname == SSH_CANONICALISE_NO)
 293                 return 0;
 294         /*
 295          * Don't attempt to canonicalize names that will be interpreted by
 296          * a proxy unless the user specifically requests so.
 297          */
 298         if (!option_clear_or_none(options.proxy_command) &&
 299             options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS)
 300                 return 0;
 301         debug3("%s: check \"%s\" CNAME \"%s\"", __func__, *namep, cname);
 302         for (i = 0; i < options.num_permitted_cnames; i++) {
 303                 rule = options.permitted_cnames + i;
 304                 if (match_pattern_list(*namep, rule->source_list,
 305                     strlen(rule->source_list), 1) != 1 ||
 306                     match_pattern_list(cname, rule->target_list,
 307                     strlen(rule->target_list), 1) != 1)
 308                         continue;
 309                 verbose("Canonicalized DNS aliased hostname "
 310                     "\"%s\" => \"%s\"", *namep, cname);
 311                 free(*namep);
 312                 *namep = xstrdup(cname);
 313                 return 1;
 314         }
 315         return 0;
 316 }
 317
 318 /*
 319  * Attempt to resolve the supplied hostname after applying the user's
 320  * canonicalization rules. Returns the address list for the host or NULL
 321  * if no name was found after canonicalization.
 322  * NB. this function must operate with a options having undefined members.
 323  */
 324 static struct addrinfo *
 325 resolve_canonicalize(char **hostp, int port)
 326 {
 327         int i, ndots;
 328         char *cp, *fullhost, cname_target[NI_MAXHOST];
 329         struct addrinfo *addrs;
 330
 331         if (options.canonicalize_hostname == SSH_CANONICALISE_NO)
 332                 return NULL;
 333
 334         /*
 335          * Don't attempt to canonicalize names that will be interpreted by
 336          * a proxy unless the user specifically requests so.
 337          */
 338         if (!option_clear_or_none(options.proxy_command) &&
 339             options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS)
 340                 return NULL;
 341
 342         /* Don't apply canonicalization to sufficiently-qualified hostnames */
 343         ndots = 0;
 344         for (cp = *hostp; *cp != '\0'; cp++) {
 345                 if (*cp == '.')
 346                         ndots++;
 347         }
 348         if (ndots > options.canonicalize_max_dots) {
 349                 debug3("%s: not canonicalizing hostname \"%s\" (max dots %d)",
 350                     __func__, *hostp, options.canonicalize_max_dots);
 351                 return NULL;
 352         }
 353         /* Attempt each supplied suffix */
 354         for (i = 0; i < options.num_canonical_domains; i++) {
 355                 *cname_target = '\0';
 356                 xasprintf(&fullhost, "%s.%s.", *hostp,
 357                     options.canonical_domains[i]);
 358                 debug3("%s: attempting \"%s\" => \"%s\"", __func__,
 359                     *hostp, fullhost);
 360                 if ((addrs = resolve_host(fullhost, port, 0,
 361                     cname_target, sizeof(cname_target))) == NULL) {
 362                         free(fullhost);
 363                         continue;
 364                 }
 365                 /* Remove trailing '.' */
 366                 fullhost[strlen(fullhost) - 1] = '\0';
 367                 /* Follow CNAME if requested */
 368                 if (!check_follow_cname(&fullhost, cname_target)) {
 369                         debug("Canonicalized hostname \"%s\" => \"%s\"",
 370                             *hostp, fullhost);
 371                 }
 372                 free(*hostp);
 373                 *hostp = fullhost;
 374                 return addrs;
 375         }
 376         if (!options.canonicalize_fallback_local)
 377                 fatal("%s: Could not resolve host \"%s\"", __progname, *hostp);
 378         debug2("%s: host %s not found in any suffix", __func__, *hostp);
 379         return NULL;
 380 }
 381
 382 /*
 383  * Read per-user configuration file.  Ignore the system wide config
 384  * file if the user specifies a config file on the command line.
 385  */
 386 static void
 387 process_config_files(struct passwd *pw)
 388 {
 389         char buf[MAXPATHLEN];
 390         int r;
 391
 392         if (config != NULL) {
 393                 if (strcasecmp(config, "none") != 0 &&
 394                     !read_config_file(config, pw, host, &options,
 395                     SSHCONF_USERCONF))
 396                         fatal("Can't open user config file %.100s: "
 397                             "%.100s", config, strerror(errno));
 398         } else {
 399                 r = snprintf(buf, sizeof buf, "%s/%s", pw->pw_dir,
 400                     _PATH_SSH_USER_CONFFILE);
 401                 if (r > 0 && (size_t)r < sizeof(buf))
 402                         (void)read_config_file(buf, pw, host, &options,
 403                              SSHCONF_CHECKPERM|SSHCONF_USERCONF);
 404
 405                 /* Read systemwide configuration file after user config. */
 406                 (void)read_config_file(_PATH_HOST_CONFIG_FILE, pw, host,
 407                     &options, 0);
 408         }
 409 }
 410
 411 /*
 412  * Main program for the ssh client.
 413  */
 414 int
 415 main(int ac, char **av)
 416 {
 417         int i, r, opt, exit_status, use_syslog;
 418         char *p, *cp, *line, *argv0, buf[MAXPATHLEN], *host_arg, *logfile;
 419         char thishost[NI_MAXHOST], shorthost[NI_MAXHOST], portstr[NI_MAXSERV];
 420         char cname[NI_MAXHOST];
 421         struct stat st;
 422         struct passwd *pw;
 423         int timeout_ms;
 424         extern int optind, optreset;
 425         extern char *optarg;
 426         struct Forward fwd;
 427         struct addrinfo *addrs = NULL;
 428         struct ssh_digest_ctx *md;
 429         u_char conn_hash[SSH_DIGEST_MAX_LENGTH];
 430         char *conn_hash_hex;
 431
 432         /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
 433         sanitise_stdfd();
 434
 435         __progname = ssh_get_progname(av[0]);
 436
 437 #ifndef HAVE_SETPROCTITLE
 438         /* Prepare for later setproctitle emulation */
 439         /* Save argv so it isn't clobbered by setproctitle() emulation */
 440         saved_av = xcalloc(ac + 1, sizeof(*saved_av));
 441         for (i = 0; i < ac; i++)
 442                 saved_av[i] = xstrdup(av[i]);
 443         saved_av[i] = NULL;
 444         compat_init_setproctitle(ac, av);
 445         av = saved_av;
 446 #endif
 447
 448         /*
 449          * Discard other fds that are hanging around. These can cause problem
 450          * with backgrounded ssh processes started by ControlPersist.
 451          */
 452         closefrom(STDERR_FILENO + 1);
 453
 454         /*
 455          * Save the original real uid.  It will be needed later (uid-swapping
 456          * may clobber the real uid).
 457          */
 458         original_real_uid = getuid();
 459         original_effective_uid = geteuid();
 460
 461         /*
 462          * Use uid-swapping to give up root privileges for the duration of
 463          * option processing.  We will re-instantiate the rights when we are
 464          * ready to create the privileged port, and will permanently drop
 465          * them when the port has been created (actually, when the connection
 466          * has been made, as we may need to create the port several times).
 467          */
 468         PRIV_END;
 469
 470 #ifdef HAVE_SETRLIMIT
 471         /* If we are installed setuid root be careful to not drop core. */
 472         if (original_real_uid != original_effective_uid) {
 473                 struct rlimit rlim;
 474                 rlim.rlim_cur = rlim.rlim_max = 0;
 475                 if (setrlimit(RLIMIT_CORE, &rlim) < 0)
 476                         fatal("setrlimit failed: %.100s", strerror(errno));
 477         }
 478 #endif
 479         /* Get user data. */
 480         pw = getpwuid(original_real_uid);
 481         if (!pw) {
 482                 logit("No user exists for uid %lu", (u_long)original_real_uid);
 483                 exit(255);
 484         }
 485         /* Take a copy of the returned structure. */
 486         pw = pwcopy(pw);
 487
 488         /*
 489          * Set our umask to something reasonable, as some files are created
 490          * with the default umask.  This will make them world-readable but
 491          * writable only by the owner, which is ok for all files for which we
 492          * don't set the modes explicitly.
 493          */
 494         umask(022);
 495
 496         /*
 497          * Initialize option structure to indicate that no values have been
 498          * set.
 499          */
 500         initialize_options(&options);
 501
 502         /* Parse command-line arguments. */
 503         host = NULL;
 504         use_syslog = 0;
 505         logfile = NULL;
 506         argv0 = av[0];
 507
 508  again:
 509         while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx"
 510             "ACD:E:F:I:KL:MNO:PQ:R:S:TVw:W:XYy")) != -1) {
 511                 switch (opt) {
 512                 case '1':
 513                         options.protocol = SSH_PROTO_1;
 514                         break;
 515                 case '2':
 516                         options.protocol = SSH_PROTO_2;
 517                         break;
 518                 case '4':
 519                         options.address_family = AF_INET;
 520                         break;
 521                 case '6':
 522                         options.address_family = AF_INET6;
 523                         break;
 524                 case 'n':
 525                         stdin_null_flag = 1;
 526                         break;
 527                 case 'f':
 528                         fork_after_authentication_flag = 1;
 529                         stdin_null_flag = 1;
 530                         break;
 531                 case 'x':
 532                         options.forward_x11 = 0;
 533                         break;
 534                 case 'X':
 535                         options.forward_x11 = 1;
 536                         break;
 537                 case 'y':
 538                         use_syslog = 1;
 539                         break;
 540                 case 'E':
 541                         logfile = xstrdup(optarg);
 542                         break;
 543                 case 'Y':
 544                         options.forward_x11 = 1;
 545                         options.forward_x11_trusted = 1;
 546                         break;
 547                 case 'g':
 548                         options.fwd_opts.gateway_ports = 1;
 549                         break;
 550                 case 'O':
 551                         if (stdio_forward_host != NULL)
 552                                 fatal("Cannot specify multiplexing "
 553                                     "command with -W");
 554                         else if (muxclient_command != 0)
 555                                 fatal("Multiplexing command already specified");
 556                         if (strcmp(optarg, "check") == 0)
 557                                 muxclient_command = SSHMUX_COMMAND_ALIVE_CHECK;
 558                         else if (strcmp(optarg, "forward") == 0)
 559                                 muxclient_command = SSHMUX_COMMAND_FORWARD;
 560                         else if (strcmp(optarg, "exit") == 0)
 561                                 muxclient_command = SSHMUX_COMMAND_TERMINATE;
 562                         else if (strcmp(optarg, "stop") == 0)
 563                                 muxclient_command = SSHMUX_COMMAND_STOP;
 564                         else if (strcmp(optarg, "cancel") == 0)
 565                                 muxclient_command = SSHMUX_COMMAND_CANCEL_FWD;
 566                         else
 567                                 fatal("Invalid multiplex command.");
 568                         break;
 569                 case 'P':       /* deprecated */
 570                         options.use_privileged_port = 0;
 571                         break;
 572                 case 'Q':
 573                         cp = NULL;
 574                         if (strcmp(optarg, "cipher") == 0)
 575                                 cp = cipher_alg_list('\n', 0);
 576                         else if (strcmp(optarg, "cipher-auth") == 0)
 577                                 cp = cipher_alg_list('\n', 1);
 578                         else if (strcmp(optarg, "mac") == 0)
 579                                 cp = mac_alg_list('\n');
 580                         else if (strcmp(optarg, "kex") == 0)
 581                                 cp = kex_alg_list('\n');
 582                         else if (strcmp(optarg, "key") == 0)
 583                                 cp = key_alg_list(0, 0);
 584                         else if (strcmp(optarg, "key-cert") == 0)
 585                                 cp = key_alg_list(1, 0);
 586                         else if (strcmp(optarg, "key-plain") == 0)
 587                                 cp = key_alg_list(0, 1);
 588                         if (cp == NULL)
 589                                 fatal("Unsupported query \"%s\"", optarg);
 590                         printf("%s\n", cp);
 591                         free(cp);
 592                         exit(0);
 593                         break;
 594                 case 'a':
 595                         options.forward_agent = 0;
 596                         break;
 597                 case 'A':
 598                         options.forward_agent = 1;
 599                         break;
 600                 case 'k':
 601                         options.gss_deleg_creds = 0;
 602                         break;
 603                 case 'K':
 604                         options.gss_authentication = 1;
 605                         options.gss_deleg_creds = 1;
 606                         break;
 607                 case 'i':
 608                         if (stat(optarg, &st) < 0) {
 609                                 fprintf(stderr, "Warning: Identity file %s "
 610                                     "not accessible: %s.\n", optarg,
 611                                     strerror(errno));
 612                                 break;
 613                         }
 614                         add_identity_file(&options, NULL, optarg, 1);
 615                         break;
 616                 case 'I':
 617 #ifdef ENABLE_PKCS11
 618                         options.pkcs11_provider = xstrdup(optarg);
 619 #else
 620                         fprintf(stderr, "no support for PKCS#11.\n");
 621 #endif
 622                         break;
 623                 case 't':
 624                         if (options.request_tty == REQUEST_TTY_YES)
 625                                 options.request_tty = REQUEST_TTY_FORCE;
 626                         else
 627                                 options.request_tty = REQUEST_TTY_YES;
 628                         break;
 629                 case 'v':
 630                         if (debug_flag == 0) {
 631                                 debug_flag = 1;
 632                                 options.log_level = SYSLOG_LEVEL_DEBUG1;
 633                         } else {
 634                                 if (options.log_level < SYSLOG_LEVEL_DEBUG3)
 635                                         options.log_level++;
 636                         }
 637                         break;
 638                 case 'V':
 639                         if (options.version_addendum &&
 640                             *options.version_addendum != '\0')
 641                                 fprintf(stderr, "%s%s %s, %s\n", SSH_RELEASE,
 642                                     options.hpn_disabled ? "" : SSH_VERSION_HPN,
 643                                     options.version_addendum,
 644                                     SSLeay_version(SSLEAY_VERSION));
 645                         else
 646                                 fprintf(stderr, "%s%s, %s\n",
 647                                     SSH_RELEASE,
 648                                     options.hpn_disabled ? "" : SSH_VERSION_HPN,
 649 #ifdef WITH_OPENSSL
 650                                     SSLeay_version(SSLEAY_VERSION)
 651 #else
 652                                     "without OpenSSL"
 653 #endif
 654                                 );
 655                         if (opt == 'V')
 656                                 exit(0);
 657                         break;
 658                 case 'w':
 659                         if (options.tun_open == -1)
 660                                 options.tun_open = SSH_TUNMODE_DEFAULT;
 661                         options.tun_local = a2tun(optarg, &options.tun_remote);
 662                         if (options.tun_local == SSH_TUNID_ERR) {
 663                                 fprintf(stderr,
 664                                     "Bad tun device '%s'\n", optarg);
 665                                 exit(255);
 666                         }
 667                         break;
 668                 case 'W':
 669                         if (stdio_forward_host != NULL)
 670                                 fatal("stdio forward already specified");
 671                         if (muxclient_command != 0)
 672                                 fatal("Cannot specify stdio forward with -O");
 673                         if (parse_forward(&fwd, optarg, 1, 0)) {
 674                                 stdio_forward_host = fwd.listen_host;
 675                                 stdio_forward_port = fwd.listen_port;
 676                                 free(fwd.connect_host);
 677                         } else {
 678                                 fprintf(stderr,
 679                                     "Bad stdio forwarding specification '%s'\n",
 680                                     optarg);
 681                                 exit(255);
 682                         }
 683                         options.request_tty = REQUEST_TTY_NO;
 684                         no_shell_flag = 1;
 685                         options.clear_forwardings = 1;
 686                         options.exit_on_forward_failure = 1;
 687                         break;
 688                 case 'q':
 689                         options.log_level = SYSLOG_LEVEL_QUIET;
 690                         break;
 691                 case 'e':
 692                         if (optarg[0] == '^' && optarg[2] == 0 &&
 693                             (u_char) optarg[1] >= 64 &&
 694                             (u_char) optarg[1] < 128)
 695                                 options.escape_char = (u_char) optarg[1] & 31;
 696                         else if (strlen(optarg) == 1)
 697                                 options.escape_char = (u_char) optarg[0];
 698                         else if (strcmp(optarg, "none") == 0)
 699                                 options.escape_char = SSH_ESCAPECHAR_NONE;
 700                         else {
 701                                 fprintf(stderr, "Bad escape character '%s'.\n",
 702                                     optarg);
 703                                 exit(255);
 704                         }
 705                         break;
 706                 case 'c':
 707                         if (ciphers_valid(optarg)) {
 708                                 /* SSH2 only */
 709                                 options.ciphers = xstrdup(optarg);
 710                                 options.cipher = SSH_CIPHER_INVALID;
 711                         } else {
 712                                 /* SSH1 only */
 713                                 options.cipher = cipher_number(optarg);
 714                                 if (options.cipher == -1) {
 715                                         fprintf(stderr,
 716                                             "Unknown cipher type '%s'\n",
 717                                             optarg);
 718                                         exit(255);
 719                                 }
 720                                 if (options.cipher == SSH_CIPHER_3DES)
 721                                         options.ciphers = "3des-cbc";
 722                                 else if (options.cipher == SSH_CIPHER_BLOWFISH)
 723                                         options.ciphers = "blowfish-cbc";
 724                                 else
 725                                         options.ciphers = (char *)-1;
 726                         }
 727                         break;
 728                 case 'm':
 729                         if (mac_valid(optarg))
 730                                 options.macs = xstrdup(optarg);
 731                         else {
 732                                 fprintf(stderr, "Unknown mac type '%s'\n",
 733                                     optarg);
 734                                 exit(255);
 735                         }
 736                         break;
 737                 case 'M':
 738                         if (options.control_master == SSHCTL_MASTER_YES)
 739                                 options.control_master = SSHCTL_MASTER_ASK;
 740                         else
 741                                 options.control_master = SSHCTL_MASTER_YES;
 742                         break;
 743                 case 'p':
 744                         options.port = a2port(optarg);
 745                         if (options.port <= 0) {
 746                                 fprintf(stderr, "Bad port '%s'\n", optarg);
 747                                 exit(255);
 748                         }
 749                         break;
 750                 case 'l':
 751                         options.user = optarg;
 752                         break;
 753
 754                 case 'L':
 755                         if (parse_forward(&fwd, optarg, 0, 0))
 756                                 add_local_forward(&options, &fwd);
 757                         else {
 758                                 fprintf(stderr,
 759                                     "Bad local forwarding specification '%s'\n",
 760                                     optarg);
 761                                 exit(255);
 762                         }
 763                         break;
 764
 765                 case 'R':
 766                         if (parse_forward(&fwd, optarg, 0, 1)) {
 767                                 add_remote_forward(&options, &fwd);
 768                         } else {
 769                                 fprintf(stderr,
 770                                     "Bad remote forwarding specification "
 771                                     "'%s'\n", optarg);
 772                                 exit(255);
 773                         }
 774                         break;
 775
 776                 case 'D':
 777                         if (parse_forward(&fwd, optarg, 1, 0)) {
 778                                 add_local_forward(&options, &fwd);
 779                         } else {
 780                                 fprintf(stderr,
 781                                     "Bad dynamic forwarding specification "
 782                                     "'%s'\n", optarg);
 783                                 exit(255);
 784                         }
 785                         break;
 786
 787                 case 'C':
 788                         options.compression = 1;
 789                         break;
 790                 case 'N':
 791                         no_shell_flag = 1;
 792                         options.request_tty = REQUEST_TTY_NO;
 793                         break;
 794                 case 'T':
 795                         options.request_tty = REQUEST_TTY_NO;
 796                         /* ensure that the user doesn't try to backdoor a */
 797                         /* null cipher switch on an interactive session */
 798                         /* so explicitly disable it no matter what */
 799                         options.none_switch=0;
 800                         break;
 801                 case 'o':
 802                         line = xstrdup(optarg);
 803                         if (process_config_line(&options, pw, host ? host : "",
 804                             line, "command-line", 0, NULL, SSHCONF_USERCONF)
 805                             != 0)
 806                                 exit(255);
 807                         free(line);
 808                         break;
 809                 case 's':
 810                         subsystem_flag = 1;
 811                         break;
 812                 case 'S':
 813                         if (options.control_path != NULL)
 814                                 free(options.control_path);
 815                         options.control_path = xstrdup(optarg);
 816                         break;
 817                 case 'b':
 818                         options.bind_address = optarg;
 819                         break;
 820                 case 'F':
 821                         config = optarg;
 822                         break;
 823                 default:
 824                         usage();
 825                 }
 826         }
 827
 828         ac -= optind;
 829         av += optind;
 830
 831         if (ac > 0 && !host) {
 832                 if (strrchr(*av, '@')) {
 833                         p = xstrdup(*av);
 834                         cp = strrchr(p, '@');
 835                         if (cp == NULL || cp == p)
 836                                 usage();
 837                         options.user = p;
 838                         *cp = '\0';
 839                         host = xstrdup(++cp);
 840                 } else
 841                         host = xstrdup(*av);
 842                 if (ac > 1) {
 843                         optind = optreset = 1;
 844                         goto again;
 845                 }
 846                 ac--, av++;
 847         }
 848
 849         /* Check that we got a host name. */
 850         if (!host)
 851                 usage();
 852
 853         host_arg = xstrdup(host);
 854
 855 #ifdef WITH_OPENSSL
 856         OpenSSL_add_all_algorithms();
 857         ERR_load_crypto_strings();
 858 #endif
 859
 860         /* Initialize the command to execute on remote host. */
 861         buffer_init(&command);
 862
 863         /*
 864          * Save the command to execute on the remote host in a buffer. There
 865          * is no limit on the length of the command, except by the maximum
 866          * packet size.  Also sets the tty flag if there is no command.
 867          */
 868         if (!ac) {
 869                 /* No command specified - execute shell on a tty. */
 870                 if (subsystem_flag) {
 871                         fprintf(stderr,
 872                             "You must specify a subsystem to invoke.\n");
 873                         usage();
 874                 }
 875         } else {
 876                 /* A command has been specified.  Store it into the buffer. */
 877                 for (i = 0; i < ac; i++) {
 878                         if (i)
 879                                 buffer_append(&command, " ", 1);
 880                         buffer_append(&command, av[i], strlen(av[i]));
 881                 }
 882         }
 883
 884         /* Cannot fork to background if no command. */
 885         if (fork_after_authentication_flag && buffer_len(&command) == 0 &&
 886             !no_shell_flag)
 887                 fatal("Cannot fork into background without a command "
 888                     "to execute.");
 889
 890         /*
 891          * Initialize "log" output.  Since we are the client all output
 892          * goes to stderr unless otherwise specified by -y or -E.
 893          */
 894         if (use_syslog && logfile != NULL)
 895                 fatal("Can't specify both -y and -E");
 896         if (logfile != NULL) {
 897                 log_redirect_stderr_to(logfile);
 898                 free(logfile);
 899         }
 900         log_init(argv0,
 901             options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level,
 902             SYSLOG_FACILITY_USER, !use_syslog);
 903
 904         if (debug_flag)
 905                 logit("%s, %s", SSH_RELEASE,
 906 #ifdef WITH_OPENSSL
 907                     SSLeay_version(SSLEAY_VERSION)
 908 #else
 909                     "without OpenSSL"
 910 #endif
 911                 );
 912
 913         /* Parse the configuration files */
 914         process_config_files(pw);
 915
 916         /* Hostname canonicalisation needs a few options filled. */
 917         fill_default_options_for_canonicalization(&options);
 918
 919         /* If the user has replaced the hostname then take it into use now */
 920         if (options.hostname != NULL) {
 921                 /* NB. Please keep in sync with readconf.c:match_cfg_line() */
 922                 cp = percent_expand(options.hostname,
 923                     "h", host, (char *)NULL);
 924                 free(host);
 925                 host = cp;
 926         }
 927
 928         /* If canonicalization requested then try to apply it */
 929         lowercase(host);
 930         if (options.canonicalize_hostname != SSH_CANONICALISE_NO)
 931                 addrs = resolve_canonicalize(&host, options.port);
 932
 933         /*
 934          * If CanonicalizePermittedCNAMEs have been specified but
 935          * other canonicalization did not happen (by not being requested
 936          * or by failing with fallback) then the hostname may still be changed
 937          * as a result of CNAME following.
 938          *
 939          * Try to resolve the bare hostname name using the system resolver's
 940          * usual search rules and then apply the CNAME follow rules.
 941          *
 942          * Skip the lookup if a ProxyCommand is being used unless the user
 943          * has specifically requested canonicalisation for this case via
 944          * CanonicalizeHostname=always
 945          */
 946         if (addrs == NULL && options.num_permitted_cnames != 0 &&
 947             (option_clear_or_none(options.proxy_command) ||
 948             options.canonicalize_hostname == SSH_CANONICALISE_ALWAYS)) {
 949                 if ((addrs = resolve_host(host, options.port,
 950                     option_clear_or_none(options.proxy_command),
 951                     cname, sizeof(cname))) == NULL) {
 952                         /* Don't fatal proxied host names not in the DNS */
 953                         if (option_clear_or_none(options.proxy_command))
 954                                 cleanup_exit(255); /* logged in resolve_host */
 955                 } else
 956                         check_follow_cname(&host, cname);
 957         }
 958
 959         /*
 960          * If the target hostname has changed as a result of canonicalisation
 961          * then re-parse the configuration files as new stanzas may match.
 962          */
 963         if (strcasecmp(host_arg, host) != 0) {
 964                 debug("Hostname has changed; re-reading configuration");
 965                 process_config_files(pw);
 966         }
 967
 968         /* Fill configuration defaults. */
 969         fill_default_options(&options);
 970
 971         if (options.port == 0)
 972                 options.port = default_ssh_port();
 973         channel_set_af(options.address_family);
 974
 975         /* Tidy and check options */
 976         if (options.host_key_alias != NULL)
 977                 lowercase(options.host_key_alias);
 978         if (options.proxy_command != NULL &&
 979             strcmp(options.proxy_command, "-") == 0 &&
 980             options.proxy_use_fdpass)
 981                 fatal("ProxyCommand=- and ProxyUseFDPass are incompatible");
 982 #ifndef HAVE_CYGWIN
 983         if (original_effective_uid != 0)
 984                 options.use_privileged_port = 0;
 985 #endif
 986
 987         /* reinit */
 988         log_init(argv0, options.log_level, SYSLOG_FACILITY_USER, !use_syslog);
 989
 990         if (options.request_tty == REQUEST_TTY_YES ||
 991             options.request_tty == REQUEST_TTY_FORCE)
 992                 tty_flag = 1;
 993
 994         /* Allocate a tty by default if no command specified. */
 995         if (buffer_len(&command) == 0)
 996                 tty_flag = options.request_tty != REQUEST_TTY_NO;
 997
 998         /* Force no tty */
 999         if (options.request_tty == REQUEST_TTY_NO || muxclient_command != 0)
1000                 tty_flag = 0;
1001         /* Do not allocate a tty if stdin is not a tty. */
1002         if ((!isatty(fileno(stdin)) || stdin_null_flag) &&
1003             options.request_tty != REQUEST_TTY_FORCE) {
1004                 if (tty_flag)
1005                         logit("Pseudo-terminal will not be allocated because "
1006                             "stdin is not a terminal.");
1007                 tty_flag = 0;
1008         }
1009
1010         seed_rng();
1011
1012         if (options.user == NULL)
1013                 options.user = xstrdup(pw->pw_name);
1014
1015         if (gethostname(thishost, sizeof(thishost)) == -1)
1016                 fatal("gethostname: %s", strerror(errno));
1017         strlcpy(shorthost, thishost, sizeof(shorthost));
1018         shorthost[strcspn(thishost, ".")] = '\0';
1019         snprintf(portstr, sizeof(portstr), "%d", options.port);
1020
1021         if ((md = ssh_digest_start(SSH_DIGEST_SHA1)) == NULL ||
1022             ssh_digest_update(md, thishost, strlen(thishost)) < 0 ||
1023             ssh_digest_update(md, host, strlen(host)) < 0 ||
1024             ssh_digest_update(md, portstr, strlen(portstr)) < 0 ||
1025             ssh_digest_update(md, options.user, strlen(options.user)) < 0 ||
1026             ssh_digest_final(md, conn_hash, sizeof(conn_hash)) < 0)
1027                 fatal("%s: mux digest failed", __func__);
1028         ssh_digest_free(md);
1029         conn_hash_hex = tohex(conn_hash, ssh_digest_bytes(SSH_DIGEST_SHA1));
1030
1031         if (options.local_command != NULL) {
1032                 debug3("expanding LocalCommand: %s", options.local_command);
1033                 cp = options.local_command;
1034                 options.local_command = percent_expand(cp,
1035                     "C", conn_hash_hex,
1036                     "L", shorthost,
1037                     "d", pw->pw_dir,
1038                     "h", host,
1039                     "l", thishost,
1040                     "n", host_arg,
1041                     "p", portstr,
1042                     "r", options.user,
1043                     "u", pw->pw_name,
1044                     (char *)NULL);
1045                 debug3("expanded LocalCommand: %s", options.local_command);
1046                 free(cp);
1047         }
1048
1049         if (options.control_path != NULL) {
1050                 cp = tilde_expand_filename(options.control_path,
1051                     original_real_uid);
1052                 free(options.control_path);
1053                 options.control_path = percent_expand(cp,
1054                     "C", conn_hash_hex,
1055                     "L", shorthost,
1056                     "h", host,
1057                     "l", thishost,
1058                     "n", host_arg,
1059                     "p", portstr,
1060                     "r", options.user,
1061                     "u", pw->pw_name,
1062                     (char *)NULL);
1063                 free(cp);
1064         }
1065         free(conn_hash_hex);
1066
1067         if (muxclient_command != 0 && options.control_path == NULL)
1068                 fatal("No ControlPath specified for \"-O\" command");
1069         if (options.control_path != NULL)
1070                 muxclient(options.control_path);
1071
1072         /*
1073          * If hostname canonicalisation was not enabled, then we may not
1074          * have yet resolved the hostname. Do so now.
1075          */
1076         if (addrs == NULL && options.proxy_command == NULL) {
1077                 if ((addrs = resolve_host(host, options.port, 1,
1078                     cname, sizeof(cname))) == NULL)
1079                         cleanup_exit(255); /* resolve_host logs the error */
1080         }
1081
1082         timeout_ms = options.connection_timeout * 1000;
1083
1084         /* Open a connection to the remote host. */
1085         if (ssh_connect(host, addrs, &hostaddr, options.port,
1086             options.address_family, options.connection_attempts,
1087             &timeout_ms, options.tcp_keep_alive,
1088             options.use_privileged_port) != 0)
1089                 exit(255);
1090
1091         if (addrs != NULL)
1092                 freeaddrinfo(addrs);
1093
1094         packet_set_timeout(options.server_alive_interval,
1095             options.server_alive_count_max);
1096
1097         if (timeout_ms > 0)
1098                 debug3("timeout: %d ms remain after connect", timeout_ms);
1099
1100         /*
1101          * If we successfully made the connection, load the host private key
1102          * in case we will need it later for combined rsa-rhosts
1103          * authentication. This must be done before releasing extra
1104          * privileges, because the file is only readable by root.
1105          * If we cannot access the private keys, load the public keys
1106          * instead and try to execute the ssh-keysign helper instead.
1107          */
1108         sensitive_data.nkeys = 0;
1109         sensitive_data.keys = NULL;
1110         sensitive_data.external_keysign = 0;
1111         if (options.rhosts_rsa_authentication ||
1112             options.hostbased_authentication) {
1113                 sensitive_data.nkeys = 9;
1114                 sensitive_data.keys = xcalloc(sensitive_data.nkeys,
1115                     sizeof(Key));
1116                 for (i = 0; i < sensitive_data.nkeys; i++)
1117                         sensitive_data.keys[i] = NULL;
1118
1119                 PRIV_START;
1120                 sensitive_data.keys[0] = key_load_private_type(KEY_RSA1,
1121                     _PATH_HOST_KEY_FILE, "", NULL, NULL);
1122                 sensitive_data.keys[1] = key_load_private_cert(KEY_DSA,
1123                     _PATH_HOST_DSA_KEY_FILE, "", NULL);
1124 #ifdef OPENSSL_HAS_ECC
1125                 sensitive_data.keys[2] = key_load_private_cert(KEY_ECDSA,
1126                     _PATH_HOST_ECDSA_KEY_FILE, "", NULL);
1127 #endif
1128                 sensitive_data.keys[3] = key_load_private_cert(KEY_RSA,
1129                     _PATH_HOST_RSA_KEY_FILE, "", NULL);
1130                 sensitive_data.keys[4] = key_load_private_cert(KEY_ED25519,
1131                     _PATH_HOST_ED25519_KEY_FILE, "", NULL);
1132                 sensitive_data.keys[5] = key_load_private_type(KEY_DSA,
1133                     _PATH_HOST_DSA_KEY_FILE, "", NULL, NULL);
1134 #ifdef OPENSSL_HAS_ECC
1135                 sensitive_data.keys[6] = key_load_private_type(KEY_ECDSA,
1136                     _PATH_HOST_ECDSA_KEY_FILE, "", NULL, NULL);
1137 #endif
1138                 sensitive_data.keys[7] = key_load_private_type(KEY_RSA,
1139                     _PATH_HOST_RSA_KEY_FILE, "", NULL, NULL);
1140                 sensitive_data.keys[8] = key_load_private_type(KEY_ED25519,
1141                     _PATH_HOST_ED25519_KEY_FILE, "", NULL, NULL);
1142                 PRIV_END;
1143
1144                 if (options.hostbased_authentication == 1 &&
1145                     sensitive_data.keys[0] == NULL &&
1146                     sensitive_data.keys[5] == NULL &&
1147                     sensitive_data.keys[6] == NULL &&
1148                     sensitive_data.keys[7] == NULL &&
1149                     sensitive_data.keys[8] == NULL) {
1150                         sensitive_data.keys[1] = key_load_cert(
1151                             _PATH_HOST_DSA_KEY_FILE);
1152 #ifdef OPENSSL_HAS_ECC
1153                         sensitive_data.keys[2] = key_load_cert(
1154                             _PATH_HOST_ECDSA_KEY_FILE);
1155 #endif
1156                         sensitive_data.keys[3] = key_load_cert(
1157                             _PATH_HOST_RSA_KEY_FILE);
1158                         sensitive_data.keys[4] = key_load_cert(
1159                             _PATH_HOST_ED25519_KEY_FILE);
1160                         sensitive_data.keys[5] = key_load_public(
1161                             _PATH_HOST_DSA_KEY_FILE, NULL);
1162 #ifdef OPENSSL_HAS_ECC
1163                         sensitive_data.keys[6] = key_load_public(
1164                             _PATH_HOST_ECDSA_KEY_FILE, NULL);
1165 #endif
1166                         sensitive_data.keys[7] = key_load_public(
1167                             _PATH_HOST_RSA_KEY_FILE, NULL);
1168                         sensitive_data.keys[8] = key_load_public(
1169                             _PATH_HOST_ED25519_KEY_FILE, NULL);
1170                         sensitive_data.external_keysign = 1;
1171                 }
1172         }
1173         /*
1174          * Get rid of any extra privileges that we may have.  We will no
1175          * longer need them.  Also, extra privileges could make it very hard
1176          * to read identity files and other non-world-readable files from the
1177          * user's home directory if it happens to be on a NFS volume where
1178          * root is mapped to nobody.
1179          */
1180         if (original_effective_uid == 0) {
1181                 PRIV_START;
1182                 permanently_set_uid(pw);
1183         }
1184
1185         /*
1186          * Now that we are back to our own permissions, create ~/.ssh
1187          * directory if it doesn't already exist.
1188          */
1189         if (config == NULL) {
1190                 r = snprintf(buf, sizeof buf, "%s%s%s", pw->pw_dir,
1191                     strcmp(pw->pw_dir, "/") ? "/" : "", _PATH_SSH_USER_DIR);
1192                 if (r > 0 && (size_t)r < sizeof(buf) && stat(buf, &st) < 0) {
1193 #ifdef WITH_SELINUX
1194                         ssh_selinux_setfscreatecon(buf);
1195 #endif
1196                         if (mkdir(buf, 0700) < 0)
1197                                 error("Could not create directory '%.200s'.",
1198                                     buf);
1199 #ifdef WITH_SELINUX
1200                         ssh_selinux_setfscreatecon(NULL);
1201 #endif
1202                 }
1203         }
1204         /* load options.identity_files */
1205         load_public_identity_files();
1206
1207         /* Expand ~ in known host file names. */
1208         tilde_expand_paths(options.system_hostfiles,
1209             options.num_system_hostfiles);
1210         tilde_expand_paths(options.user_hostfiles, options.num_user_hostfiles);
1211
1212         signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */
1213         signal(SIGCHLD, main_sigchld_handler);
1214
1215         /* Log into the remote system.  Never returns if the login fails. */
1216         ssh_login(&sensitive_data, host, (struct sockaddr *)&hostaddr,
1217             options.port, pw, timeout_ms);
1218
1219         if (packet_connection_is_on_socket()) {
1220                 verbose("Authenticated to %s ([%s]:%d).", host,
1221                     get_remote_ipaddr(), get_remote_port());
1222         } else {
1223                 verbose("Authenticated to %s (via proxy).", host);
1224         }
1225
1226         /* We no longer need the private host keys.  Clear them now. */
1227         if (sensitive_data.nkeys != 0) {
1228                 for (i = 0; i < sensitive_data.nkeys; i++) {
1229                         if (sensitive_data.keys[i] != NULL) {
1230                                 /* Destroys contents safely */
1231                                 debug3("clear hostkey %d", i);
1232                                 key_free(sensitive_data.keys[i]);
1233                                 sensitive_data.keys[i] = NULL;
1234                         }
1235                 }
1236                 free(sensitive_data.keys);
1237         }
1238         for (i = 0; i < options.num_identity_files; i++) {
1239                 free(options.identity_files[i]);
1240                 options.identity_files[i] = NULL;
1241                 if (options.identity_keys[i]) {
1242                         key_free(options.identity_keys[i]);
1243                         options.identity_keys[i] = NULL;
1244                 }
1245         }
1246
1247         exit_status = compat20 ? ssh_session2() : ssh_session();
1248         packet_close();
1249
1250         if (options.control_path != NULL && muxserver_sock != -1)
1251                 unlink(options.control_path);
1252
1253         /* Kill ProxyCommand if it is running. */
1254         ssh_kill_proxy_command();
1255
1256         return exit_status;
1257 }
1258
1259 static void
1260 control_persist_detach(void)
1261 {
1262         pid_t pid;
1263         int devnull;
1264
1265         debug("%s: backgrounding master process", __func__);
1266
1267         /*
1268          * master (current process) into the background, and make the
1269          * foreground process a client of the backgrounded master.
1270          */
1271         switch ((pid = fork())) {
1272         case -1:
1273                 fatal("%s: fork: %s", __func__, strerror(errno));
1274         case 0:
1275                 /* Child: master process continues mainloop */
1276                 break;
1277         default:
1278                 /* Parent: set up mux slave to connect to backgrounded master */
1279                 debug2("%s: background process is %ld", __func__, (long)pid);
1280                 stdin_null_flag = ostdin_null_flag;
1281                 options.request_tty = orequest_tty;
1282                 tty_flag = otty_flag;
1283                 close(muxserver_sock);
1284                 muxserver_sock = -1;
1285                 options.control_master = SSHCTL_MASTER_NO;
1286                 muxclient(options.control_path);
1287                 /* muxclient() doesn't return on success. */
1288                 fatal("Failed to connect to new control master");
1289         }
1290         if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1) {
1291                 error("%s: open(\"/dev/null\"): %s", __func__,
1292                     strerror(errno));
1293         } else {
1294                 if (dup2(devnull, STDIN_FILENO) == -1 ||
1295                     dup2(devnull, STDOUT_FILENO) == -1)
1296                         error("%s: dup2: %s", __func__, strerror(errno));
1297                 if (devnull > STDERR_FILENO)
1298                         close(devnull);
1299         }
1300         daemon(1, 1);
1301         setproctitle("%s [mux]", options.control_path);
1302 }
1303
1304 extern const EVP_CIPHER *evp_aes_ctr_mt(void);
1305
1306 /* Do fork() after authentication. Used by "ssh -f" */
1307 static void
1308 fork_postauth(void)
1309 {
1310         if (need_controlpersist_detach)
1311                 control_persist_detach();
1312         debug("forking to background");
1313         fork_after_authentication_flag = 0;
1314         if (daemon(1, 1) < 0)
1315                 fatal("daemon() failed: %.200s", strerror(errno));
1316 }
1317
1318 /* Callback for remote forward global requests */
1319 static void
1320 ssh_confirm_remote_forward(int type, u_int32_t seq, void *ctxt)
1321 {
1322         struct Forward *rfwd = (struct Forward *)ctxt;
1323
1324         /* XXX verbose() on failure? */
1325         debug("remote forward %s for: listen %s%s%d, connect %s:%d",
1326             type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure",
1327             rfwd->listen_path ? rfwd->listen_path :
1328             rfwd->listen_host ? rfwd->listen_host : "",
1329             (rfwd->listen_path || rfwd->listen_host) ? ":" : "",
1330             rfwd->listen_port, rfwd->connect_path ? rfwd->connect_path :
1331             rfwd->connect_host, rfwd->connect_port);
1332         if (rfwd->listen_path == NULL && rfwd->listen_port == 0) {
1333                 if (type == SSH2_MSG_REQUEST_SUCCESS) {
1334                         rfwd->allocated_port = packet_get_int();
1335                         logit("Allocated port %u for remote forward to %s:%d",
1336                             rfwd->allocated_port,
1337                             rfwd->connect_host, rfwd->connect_port);
1338                         channel_update_permitted_opens(rfwd->handle,
1339                             rfwd->allocated_port);
1340                 } else {
1341                         channel_update_permitted_opens(rfwd->handle, -1);
1342                 }
1343         }
1344
1345         if (type == SSH2_MSG_REQUEST_FAILURE) {
1346                 if (options.exit_on_forward_failure) {
1347                         if (rfwd->listen_path != NULL)
1348                                 fatal("Error: remote port forwarding failed "
1349                                     "for listen path %s", rfwd->listen_path);
1350                         else
1351                                 fatal("Error: remote port forwarding failed "
1352                                     "for listen port %d", rfwd->listen_port);
1353                 } else {
1354                         if (rfwd->listen_path != NULL)
1355                                 logit("Warning: remote port forwarding failed "
1356                                     "for listen path %s", rfwd->listen_path);
1357                         else
1358                                 logit("Warning: remote port forwarding failed "
1359                                     "for listen port %d", rfwd->listen_port);
1360                 }
1361         }
1362         if (++remote_forward_confirms_received == options.num_remote_forwards) {
1363                 debug("All remote forwarding requests processed");
1364                 if (fork_after_authentication_flag)
1365                         fork_postauth();
1366         }
1367 }
1368
1369 static void
1370 client_cleanup_stdio_fwd(int id, void *arg)
1371 {
1372         debug("stdio forwarding: done");
1373         cleanup_exit(0);
1374 }
1375
1376 static void
1377 ssh_stdio_confirm(int id, int success, void *arg)
1378 {
1379         if (!success)
1380                 fatal("stdio forwarding failed");
1381 }
1382
1383 static void
1384 ssh_init_stdio_forwarding(void)
1385 {
1386         Channel *c;
1387         int in, out;
1388
1389         if (stdio_forward_host == NULL)
1390                 return;
1391         if (!compat20)
1392                 fatal("stdio forwarding require Protocol 2");
1393
1394         debug3("%s: %s:%d", __func__, stdio_forward_host, stdio_forward_port);
1395
1396         if ((in = dup(STDIN_FILENO)) < 0 ||
1397             (out = dup(STDOUT_FILENO)) < 0)
1398                 fatal("channel_connect_stdio_fwd: dup() in/out failed");
1399         if ((c = channel_connect_stdio_fwd(stdio_forward_host,
1400             stdio_forward_port, in, out)) == NULL)
1401                 fatal("%s: channel_connect_stdio_fwd failed", __func__);
1402         channel_register_cleanup(c->self, client_cleanup_stdio_fwd, 0);
1403         channel_register_open_confirm(c->self, ssh_stdio_confirm, NULL);
1404 }
1405
1406 static void
1407 ssh_init_forwarding(void)
1408 {
1409         int success = 0;
1410         int i;
1411
1412         /* Initiate local TCP/IP port forwardings. */
1413         for (i = 0; i < options.num_local_forwards; i++) {
1414                 debug("Local connections to %.200s:%d forwarded to remote "
1415                     "address %.200s:%d",
1416                     (options.local_forwards[i].listen_path != NULL) ?
1417                     options.local_forwards[i].listen_path :
1418                     (options.local_forwards[i].listen_host == NULL) ?
1419                     (options.fwd_opts.gateway_ports ? "*" : "LOCALHOST") :
1420                     options.local_forwards[i].listen_host,
1421                     options.local_forwards[i].listen_port,
1422                     (options.local_forwards[i].connect_path != NULL) ?
1423                     options.local_forwards[i].connect_path :
1424                     options.local_forwards[i].connect_host,
1425                     options.local_forwards[i].connect_port);
1426                 success += channel_setup_local_fwd_listener(
1427                     &options.local_forwards[i], &options.fwd_opts);
1428         }
1429         if (i > 0 && success != i && options.exit_on_forward_failure)
1430                 fatal("Could not request local forwarding.");
1431         if (i > 0 && success == 0)
1432                 error("Could not request local forwarding.");
1433
1434         /* Initiate remote TCP/IP port forwardings. */
1435         for (i = 0; i < options.num_remote_forwards; i++) {
1436                 debug("Remote connections from %.200s:%d forwarded to "
1437                     "local address %.200s:%d",
1438                     (options.remote_forwards[i].listen_path != NULL) ?
1439                     options.remote_forwards[i].listen_path :
1440                     (options.remote_forwards[i].listen_host == NULL) ?
1441                     "LOCALHOST" : options.remote_forwards[i].listen_host,
1442                     options.remote_forwards[i].listen_port,
1443                     (options.remote_forwards[i].connect_path != NULL) ?
1444                     options.remote_forwards[i].connect_path :
1445                     options.remote_forwards[i].connect_host,
1446                     options.remote_forwards[i].connect_port);
1447                 options.remote_forwards[i].handle =
1448                     channel_request_remote_forwarding(
1449                     &options.remote_forwards[i]);
1450                 if (options.remote_forwards[i].handle < 0) {
1451                         if (options.exit_on_forward_failure)
1452                                 fatal("Could not request remote forwarding.");
1453                         else
1454                                 logit("Warning: Could not request remote "
1455                                     "forwarding.");
1456                 } else {
1457                         client_register_global_confirm(ssh_confirm_remote_forward,
1458                             &options.remote_forwards[i]);
1459                 }
1460         }
1461
1462         /* Initiate tunnel forwarding. */
1463         if (options.tun_open != SSH_TUNMODE_NO) {
1464                 if (client_request_tun_fwd(options.tun_open,
1465                     options.tun_local, options.tun_remote) == -1) {
1466                         if (options.exit_on_forward_failure)
1467                                 fatal("Could not request tunnel forwarding.");
1468                         else
1469                                 error("Could not request tunnel forwarding.");
1470                 }
1471         }
1472 }
1473
1474 static void
1475 check_agent_present(void)
1476 {
1477         if (options.forward_agent) {
1478                 /* Clear agent forwarding if we don't have an agent. */
1479                 if (!ssh_agent_present())
1480                         options.forward_agent = 0;
1481         }
1482 }
1483
1484 static int
1485 ssh_session(void)
1486 {
1487         int type;
1488         int interactive = 0;
1489         int have_tty = 0;
1490         struct winsize ws;
1491         char *cp;
1492         const char *display;
1493
1494         /* Enable compression if requested. */
1495         if (options.compression) {
1496                 debug("Requesting compression at level %d.",
1497                     options.compression_level);
1498
1499                 if (options.compression_level < 1 ||
1500                     options.compression_level > 9)
1501                         fatal("Compression level must be from 1 (fast) to "
1502                             "9 (slow, best).");
1503
1504                 /* Send the request. */
1505                 packet_start(SSH_CMSG_REQUEST_COMPRESSION);
1506                 packet_put_int(options.compression_level);
1507                 packet_send();
1508                 packet_write_wait();
1509                 type = packet_read();
1510                 if (type == SSH_SMSG_SUCCESS)
1511                         packet_start_compression(options.compression_level);
1512                 else if (type == SSH_SMSG_FAILURE)
1513                         logit("Warning: Remote host refused compression.");
1514                 else
1515                         packet_disconnect("Protocol error waiting for "
1516                             "compression response.");
1517         }
1518         /* Allocate a pseudo tty if appropriate. */
1519         if (tty_flag) {
1520                 debug("Requesting pty.");
1521
1522                 /* Start the packet. */
1523                 packet_start(SSH_CMSG_REQUEST_PTY);
1524
1525                 /* Store TERM in the packet.  There is no limit on the
1526                    length of the string. */
1527                 cp = getenv("TERM");
1528                 if (!cp)
1529                         cp = "";
1530                 packet_put_cstring(cp);
1531
1532                 /* Store window size in the packet. */
1533                 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
1534                         memset(&ws, 0, sizeof(ws));
1535                 packet_put_int((u_int)ws.ws_row);
1536                 packet_put_int((u_int)ws.ws_col);
1537                 packet_put_int((u_int)ws.ws_xpixel);
1538                 packet_put_int((u_int)ws.ws_ypixel);
1539
1540                 /* Store tty modes in the packet. */
1541                 tty_make_modes(fileno(stdin), NULL);
1542
1543                 /* Send the packet, and wait for it to leave. */
1544                 packet_send();
1545                 packet_write_wait();
1546
1547                 /* Read response from the server. */
1548                 type = packet_read();
1549                 if (type == SSH_SMSG_SUCCESS) {
1550                         interactive = 1;
1551                         have_tty = 1;
1552                 } else if (type == SSH_SMSG_FAILURE)
1553                         logit("Warning: Remote host failed or refused to "
1554                             "allocate a pseudo tty.");
1555                 else
1556                         packet_disconnect("Protocol error waiting for pty "
1557                             "request response.");
1558         }
1559         /* Request X11 forwarding if enabled and DISPLAY is set. */
1560         display = getenv("DISPLAY");
1561         if (options.forward_x11 && display != NULL) {
1562                 char *proto, *data;
1563                 /* Get reasonable local authentication information. */
1564                 client_x11_get_proto(display, options.xauth_location,
1565                     options.forward_x11_trusted,
1566                     options.forward_x11_timeout,
1567                     &proto, &data);
1568                 /* Request forwarding with authentication spoofing. */
1569                 debug("Requesting X11 forwarding with authentication "
1570                     "spoofing.");
1571                 x11_request_forwarding_with_spoofing(0, display, proto,
1572                     data, 0);
1573                 /* Read response from the server. */
1574                 type = packet_read();
1575                 if (type == SSH_SMSG_SUCCESS) {
1576                         interactive = 1;
1577                 } else if (type == SSH_SMSG_FAILURE) {
1578                         logit("Warning: Remote host denied X11 forwarding.");
1579                 } else {
1580                         packet_disconnect("Protocol error waiting for X11 "
1581                             "forwarding");
1582                 }
1583         }
1584         /* Tell the packet module whether this is an interactive session. */
1585         packet_set_interactive(interactive,
1586             options.ip_qos_interactive, options.ip_qos_bulk);
1587
1588         /* Request authentication agent forwarding if appropriate. */
1589         check_agent_present();
1590
1591         if (options.forward_agent) {
1592                 debug("Requesting authentication agent forwarding.");
1593                 auth_request_forwarding();
1594
1595                 /* Read response from the server. */
1596                 type = packet_read();
1597                 packet_check_eom();
1598                 if (type != SSH_SMSG_SUCCESS)
1599                         logit("Warning: Remote host denied authentication agent forwarding.");
1600         }
1601
1602         /* Initiate port forwardings. */
1603         ssh_init_stdio_forwarding();
1604         ssh_init_forwarding();
1605
1606         /* Execute a local command */
1607         if (options.local_command != NULL &&
1608             options.permit_local_command)
1609                 ssh_local_cmd(options.local_command);
1610
1611         /*
1612          * If requested and we are not interested in replies to remote
1613          * forwarding requests, then let ssh continue in the background.
1614          */
1615         if (fork_after_authentication_flag) {
1616                 if (options.exit_on_forward_failure &&
1617                     options.num_remote_forwards > 0) {
1618                         debug("deferring postauth fork until remote forward "
1619                             "confirmation received");
1620                 } else
1621                         fork_postauth();
1622         }
1623
1624         /*
1625          * If a command was specified on the command line, execute the
1626          * command now. Otherwise request the server to start a shell.
1627          */
1628         if (buffer_len(&command) > 0) {
1629                 int len = buffer_len(&command);
1630                 if (len > 900)
1631                         len = 900;
1632                 debug("Sending command: %.*s", len,
1633                     (u_char *)buffer_ptr(&command));
1634                 packet_start(SSH_CMSG_EXEC_CMD);
1635                 packet_put_string(buffer_ptr(&command), buffer_len(&command));
1636                 packet_send();
1637                 packet_write_wait();
1638         } else {
1639                 debug("Requesting shell.");
1640                 packet_start(SSH_CMSG_EXEC_SHELL);
1641                 packet_send();
1642                 packet_write_wait();
1643         }
1644
1645         /* Enter the interactive session. */
1646         return client_loop(have_tty, tty_flag ?
1647             options.escape_char : SSH_ESCAPECHAR_NONE, 0);
1648 }
1649
1650 /* request pty/x11/agent/tcpfwd/shell for channel */
1651 static void
1652 ssh_session2_setup(int id, int success, void *arg)
1653 {
1654         extern char **environ;
1655         const char *display;
1656         int interactive = tty_flag;
1657
1658         if (!success)
1659                 return; /* No need for error message, channels code sens one */
1660
1661         display = getenv("DISPLAY");
1662         if (options.forward_x11 && display != NULL) {
1663                 char *proto, *data;
1664                 /* Get reasonable local authentication information. */
1665                 client_x11_get_proto(display, options.xauth_location,
1666                     options.forward_x11_trusted,
1667                     options.forward_x11_timeout, &proto, &data);
1668                 /* Request forwarding with authentication spoofing. */
1669                 debug("Requesting X11 forwarding with authentication "
1670                     "spoofing.");
1671                 x11_request_forwarding_with_spoofing(id, display, proto,
1672                     data, 1);
1673                 client_expect_confirm(id, "X11 forwarding", CONFIRM_WARN);
1674                 /* XXX exit_on_forward_failure */
1675                 interactive = 1;
1676         }
1677
1678         check_agent_present();
1679         if (options.forward_agent) {
1680                 debug("Requesting authentication agent forwarding.");
1681                 channel_request_start(id, "auth-agent-req@openssh.com", 0);
1682                 packet_send();
1683         }
1684
1685         /* Tell the packet module whether this is an interactive session. */
1686         packet_set_interactive(interactive,
1687             options.ip_qos_interactive, options.ip_qos_bulk);
1688
1689         client_session2_setup(id, tty_flag, subsystem_flag, getenv("TERM"),
1690             NULL, fileno(stdin), &command, environ);
1691 }
1692
1693 /* open new channel for a session */
1694 static int
1695 ssh_session2_open(void)
1696 {
1697         Channel *c;
1698         int window, packetmax, in, out, err;
1699         int sock;
1700         int socksize;
1701         int socksizelen = sizeof(int);
1702
1703         if (stdin_null_flag) {
1704                 in = open(_PATH_DEVNULL, O_RDONLY);
1705         } else {
1706                 in = dup(STDIN_FILENO);
1707         }
1708         out = dup(STDOUT_FILENO);
1709         err = dup(STDERR_FILENO);
1710
1711         if (in < 0 || out < 0 || err < 0)
1712                 fatal("dup() in/out/err failed");
1713
1714         /* enable nonblocking unless tty */
1715         if (!isatty(in))
1716                 set_nonblock(in);
1717         if (!isatty(out))
1718                 set_nonblock(out);
1719         if (!isatty(err))
1720                 set_nonblock(err);
1721
1722         /* we need to check to see if what they want to do about buffer */
1723         /* sizes here. In a hpn to nonhpn connection we want to limit */
1724         /* the window size to something reasonable in case the far side */
1725         /* has the large window bug. In hpn to hpn connection we want to */
1726         /* use the max window size but allow the user to override it */
1727         /* lastly if they disabled hpn then use the ssh std window size */
1728
1729         /* so why don't we just do a getsockopt() here and set the */
1730         /* ssh window to that? In the case of a autotuning receive */
1731         /* window the window would get stuck at the initial buffer */
1732         /* size generally less than 96k. Therefore we need to set the */
1733         /* maximum ssh window size to the maximum hpn buffer size */
1734         /* unless the user has specifically set the tcprcvbufpoll */
1735         /* to no. In which case we *can* just set the window to the */
1736         /* minimum of the hpn buffer size and tcp receive buffer size */
1737
1738         if (tty_flag)
1739                 options.hpn_buffer_size = CHAN_SES_WINDOW_DEFAULT;
1740         else
1741                 options.hpn_buffer_size = 2*1024*1024;
1742
1743         if (datafellows & SSH_BUG_LARGEWINDOW)
1744         {
1745                 debug("HPN to Non-HPN Connection");
1746         }
1747         else
1748         {
1749                 if (options.tcp_rcv_buf_poll <= 0)
1750                 {
1751                         sock = socket(AF_INET, SOCK_STREAM, 0);
1752                         getsockopt(sock, SOL_SOCKET, SO_RCVBUF,
1753                                    &socksize, &socksizelen);
1754                         close(sock);
1755                         debug("socksize %d", socksize);
1756                         options.hpn_buffer_size = socksize;
1757                         debug ("HPNBufferSize set to TCP RWIN: %d", options.hpn_buffer_size);
1758                 }
1759                 else
1760                 {
1761                         if (options.tcp_rcv_buf > 0)
1762                         {
1763                                 /*create a socket but don't connect it */
1764                                 /* we use that the get the rcv socket size */
1765                                 sock = socket(AF_INET, SOCK_STREAM, 0);
1766                                 /* if they are using the tcp_rcv_buf option */
1767                                 /* attempt to set the buffer size to that */
1768                                 if (options.tcp_rcv_buf)
1769                                         setsockopt(sock, SOL_SOCKET, SO_RCVBUF, (void *)&options.tcp_rcv_buf,
1770                                                    sizeof(options.tcp_rcv_buf));
1771                                 getsockopt(sock, SOL_SOCKET, SO_RCVBUF,
1772                                            &socksize, &socksizelen);
1773                                 close(sock);
1774                                 debug("socksize %d", socksize);
1775                                 options.hpn_buffer_size = socksize;
1776                                 debug ("HPNBufferSize set to user TCPRcvBuf: %d", options.hpn_buffer_size);
1777                         }
1778                 }
1779         }
1780
1781         debug("Final hpn_buffer_size = %d", options.hpn_buffer_size);
1782
1783         window = options.hpn_buffer_size;
1784
1785         channel_set_hpn(options.hpn_disabled, options.hpn_buffer_size);
1786
1787         packetmax = CHAN_SES_PACKET_DEFAULT;
1788         if (tty_flag) {
1789                 window = 4*CHAN_SES_PACKET_DEFAULT;
1790                 window >>= 1;
1791                 packetmax >>= 1;
1792         }
1793         c = channel_new(
1794             "session", SSH_CHANNEL_OPENING, in, out, err,
1795             window, packetmax, CHAN_EXTENDED_WRITE,
1796             "client-session", /*nonblock*/0);
1797
1798         if ((options.tcp_rcv_buf_poll > 0) && (!options.hpn_disabled)) {
1799                 c->dynamic_window = 1;
1800                 debug ("Enabled Dynamic Window Scaling");
1801         }
1802         debug3("ssh_session2_open: channel_new: %d", c->self);
1803
1804         channel_send_open(c->self);
1805         if (!no_shell_flag)
1806                 channel_register_open_confirm(c->self,
1807                     ssh_session2_setup, NULL);
1808
1809         return c->self;
1810 }
1811
1812 static int
1813 ssh_session2(void)
1814 {
1815         int id = -1;
1816
1817         /* XXX should be pre-session */
1818         if (!options.control_persist)
1819                 ssh_init_stdio_forwarding();
1820         ssh_init_forwarding();
1821
1822         /* Start listening for multiplex clients */
1823         muxserver_listen();
1824
1825         /*
1826          * If we are in control persist mode and have a working mux listen
1827          * socket, then prepare to background ourselves and have a foreground
1828          * client attach as a control slave.
1829          * NB. we must save copies of the flags that we override for
1830          * the backgrounding, since we defer attachment of the slave until
1831          * after the connection is fully established (in particular,
1832          * async rfwd replies have been received for ExitOnForwardFailure).
1833          */
1834         if (options.control_persist && muxserver_sock != -1) {
1835                 ostdin_null_flag = stdin_null_flag;
1836                 ono_shell_flag = no_shell_flag;
1837                 orequest_tty = options.request_tty;
1838                 otty_flag = tty_flag;
1839                 stdin_null_flag = 1;
1840                 no_shell_flag = 1;
1841                 tty_flag = 0;
1842                 if (!fork_after_authentication_flag)
1843                         need_controlpersist_detach = 1;
1844                 fork_after_authentication_flag = 1;
1845         }
1846         /*
1847          * ControlPersist mux listen socket setup failed, attempt the
1848          * stdio forward setup that we skipped earlier.
1849          */
1850         if (options.control_persist && muxserver_sock == -1)
1851                 ssh_init_stdio_forwarding();
1852
1853         if (!no_shell_flag || (datafellows & SSH_BUG_DUMMYCHAN))
1854                 id = ssh_session2_open();
1855         else {
1856                 packet_set_interactive(
1857                     options.control_master == SSHCTL_MASTER_NO,
1858                     options.ip_qos_interactive, options.ip_qos_bulk);
1859         }
1860
1861         /* If we don't expect to open a new session, then disallow it */
1862         if (options.control_master == SSHCTL_MASTER_NO &&
1863             (datafellows & SSH_NEW_OPENSSH)) {
1864                 debug("Requesting no-more-sessions@openssh.com");
1865                 packet_start(SSH2_MSG_GLOBAL_REQUEST);
1866                 packet_put_cstring("no-more-sessions@openssh.com");
1867                 packet_put_char(0);
1868                 packet_send();
1869         }
1870
1871         /* Execute a local command */
1872         if (options.local_command != NULL &&
1873             options.permit_local_command)
1874                 ssh_local_cmd(options.local_command);
1875
1876         /*
1877          * If requested and we are not interested in replies to remote
1878          * forwarding requests, then let ssh continue in the background.
1879          */
1880         if (fork_after_authentication_flag) {
1881                 if (options.exit_on_forward_failure &&
1882                     options.num_remote_forwards > 0) {
1883                         debug("deferring postauth fork until remote forward "
1884                             "confirmation received");
1885                 } else
1886                         fork_postauth();
1887         }
1888
1889         if (options.use_roaming)
1890                 request_roaming();
1891
1892         return client_loop(tty_flag, tty_flag ?
1893             options.escape_char : SSH_ESCAPECHAR_NONE, id);
1894 }
1895
1896 static void
1897 load_public_identity_files(void)
1898 {
1899         char *filename, *cp, thishost[NI_MAXHOST];
1900         char *pwdir = NULL, *pwname = NULL;
1901         int i = 0;
1902         Key *public;
1903         struct passwd *pw;
1904         u_int n_ids;
1905         char *identity_files[SSH_MAX_IDENTITY_FILES];
1906         Key *identity_keys[SSH_MAX_IDENTITY_FILES];
1907 #ifdef ENABLE_PKCS11
1908         Key **keys;
1909         int nkeys;
1910 #endif /* PKCS11 */
1911
1912         n_ids = 0;
1913         memset(identity_files, 0, sizeof(identity_files));
1914         memset(identity_keys, 0, sizeof(identity_keys));
1915
1916 #ifdef ENABLE_PKCS11
1917         if (options.pkcs11_provider != NULL &&
1918             options.num_identity_files < SSH_MAX_IDENTITY_FILES &&
1919             (pkcs11_init(!options.batch_mode) == 0) &&
1920             (nkeys = pkcs11_add_provider(options.pkcs11_provider, NULL,
1921             &keys)) > 0) {
1922                 for (i = 0; i < nkeys; i++) {
1923                         if (n_ids >= SSH_MAX_IDENTITY_FILES) {
1924                                 key_free(keys[i]);
1925                                 continue;
1926                         }
1927                         identity_keys[n_ids] = keys[i];
1928                         identity_files[n_ids] =
1929                             xstrdup(options.pkcs11_provider); /* XXX */
1930                         n_ids++;
1931                 }
1932                 free(keys);
1933         }
1934 #endif /* ENABLE_PKCS11 */
1935         if ((pw = getpwuid(original_real_uid)) == NULL)
1936                 fatal("load_public_identity_files: getpwuid failed");
1937         pwname = xstrdup(pw->pw_name);
1938         pwdir = xstrdup(pw->pw_dir);
1939         if (gethostname(thishost, sizeof(thishost)) == -1)
1940                 fatal("load_public_identity_files: gethostname: %s",
1941                     strerror(errno));
1942         for (i = 0; i < options.num_identity_files; i++) {
1943                 if (n_ids >= SSH_MAX_IDENTITY_FILES ||
1944                     strcasecmp(options.identity_files[i], "none") == 0) {
1945                         free(options.identity_files[i]);
1946                         continue;
1947                 }
1948                 cp = tilde_expand_filename(options.identity_files[i],
1949                     original_real_uid);
1950                 filename = percent_expand(cp, "d", pwdir,
1951                     "u", pwname, "l", thishost, "h", host,
1952                     "r", options.user, (char *)NULL);
1953                 free(cp);
1954                 public = key_load_public(filename, NULL);
1955                 debug("identity file %s type %d", filename,
1956                     public ? public->type : -1);
1957                 free(options.identity_files[i]);
1958                 identity_files[n_ids] = filename;
1959                 identity_keys[n_ids] = public;
1960
1961                 if (++n_ids >= SSH_MAX_IDENTITY_FILES)
1962                         continue;
1963
1964                 /* Try to add the certificate variant too */
1965                 xasprintf(&cp, "%s-cert", filename);
1966                 public = key_load_public(cp, NULL);
1967                 debug("identity file %s type %d", cp,
1968                     public ? public->type : -1);
1969                 if (public == NULL) {
1970                         free(cp);
1971                         continue;
1972                 }
1973                 if (!key_is_cert(public)) {
1974                         debug("%s: key %s type %s is not a certificate",
1975                             __func__, cp, key_type(public));
1976                         key_free(public);
1977                         free(cp);
1978                         continue;
1979                 }
1980                 identity_keys[n_ids] = public;
1981                 /* point to the original path, most likely the private key */
1982                 identity_files[n_ids] = xstrdup(filename);
1983                 n_ids++;
1984         }
1985         options.num_identity_files = n_ids;
1986         memcpy(options.identity_files, identity_files, sizeof(identity_files));
1987         memcpy(options.identity_keys, identity_keys, sizeof(identity_keys));
1988
1989         explicit_bzero(pwname, strlen(pwname));
1990         free(pwname);
1991         explicit_bzero(pwdir, strlen(pwdir));
1992         free(pwdir);
1993 }
1994
1995 static void
1996 main_sigchld_handler(int sig)
1997 {
1998         int save_errno = errno;
1999         pid_t pid;
2000         int status;
2001
2002         while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
2003             (pid < 0 && errno == EINTR))
2004                 ;
2005
2006         signal(sig, main_sigchld_handler);
2007         errno = save_errno;
2008 }