crypto/openssh/ssh.c

   1 /* $OpenBSD: ssh.c,v 1.420 2015/07/30 00:01:34 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
  72 #include <netinet/in.h>
  73 #include <arpa/inet.h>
  74
  75 #ifdef WITH_OPENSSL
  76 #include <openssl/evp.h>
  77 #include <openssl/err.h>
  78 #endif
  79 #include "openbsd-compat/openssl-compat.h"
  80 #include "openbsd-compat/sys-queue.h"
  81
  82 #include "xmalloc.h"
  83 #include "ssh.h"
  84 #include "ssh1.h"
  85 #include "ssh2.h"
  86 #include "canohost.h"
  87 #include "compat.h"
  88 #include "cipher.h"
  89 #include "digest.h"
  90 #include "packet.h"
  91 #include "buffer.h"
  92 #include "channels.h"
  93 #include "key.h"
  94 #include "authfd.h"
  95 #include "authfile.h"
  96 #include "pathnames.h"
  97 #include "dispatch.h"
  98 #include "clientloop.h"
  99 #include "log.h"
 100 #include "misc.h"
 101 #include "readconf.h"
 102 #include "sshconnect.h"
 103 #include "kex.h"
 104 #include "mac.h"
 105 #include "sshpty.h"
 106 #include "match.h"
 107 #include "msg.h"
 108 #include "uidswap.h"
 109 #include "roaming.h"
 110 #include "version.h"
 111 #include "ssherr.h"
 112 #include "myproposal.h"
 113
 114 #ifdef ENABLE_PKCS11
 115 #include "ssh-pkcs11.h"
 116 #endif
 117
 118 extern char *__progname;
 119
 120 /* Saves a copy of argv for setproctitle emulation */
 121 #ifndef HAVE_SETPROCTITLE
 122 static char **saved_av;
 123 #endif
 124
 125 /* Flag indicating whether debug mode is on.  May be set on the command line. */
 126 int debug_flag = 0;
 127
 128 /* Flag indicating whether a tty should be requested */
 129 int tty_flag = 0;
 130
 131 /* don't exec a shell */
 132 int no_shell_flag = 0;
 133
 134 /*
 135  * Flag indicating that nothing should be read from stdin.  This can be set
 136  * on the command line.
 137  */
 138 int stdin_null_flag = 0;
 139
 140 /*
 141  * Flag indicating that the current process should be backgrounded and
 142  * a new slave launched in the foreground for ControlPersist.
 143  */
 144 int need_controlpersist_detach = 0;
 145
 146 /* Copies of flags for ControlPersist foreground slave */
 147 int ostdin_null_flag, ono_shell_flag, otty_flag, orequest_tty;
 148
 149 /*
 150  * Flag indicating that ssh should fork after authentication.  This is useful
 151  * so that the passphrase can be entered manually, and then ssh goes to the
 152  * background.
 153  */
 154 int fork_after_authentication_flag = 0;
 155
 156 /* forward stdio to remote host and port */
 157 char *stdio_forward_host = NULL;
 158 int stdio_forward_port = 0;
 159
 160 /*
 161  * General data structure for command line options and options configurable
 162  * in configuration files.  See readconf.h.
 163  */
 164 Options options;
 165
 166 /* optional user configfile */
 167 char *config = NULL;
 168
 169 /*
 170  * Name of the host we are connecting to.  This is the name given on the
 171  * command line, or the HostName specified for the user-supplied name in a
 172  * configuration file.
 173  */
 174 char *host;
 175
 176 /* socket address the host resolves to */
 177 struct sockaddr_storage hostaddr;
 178
 179 /* Private host keys. */
 180 Sensitive sensitive_data;
 181
 182 /* Original real UID. */
 183 uid_t original_real_uid;
 184 uid_t original_effective_uid;
 185
 186 /* command to be executed */
 187 Buffer command;
 188
 189 /* Should we execute a command or invoke a subsystem? */
 190 int subsystem_flag = 0;
 191
 192 /* # of replies received for global requests */
 193 static int remote_forward_confirms_received = 0;
 194
 195 /* mux.c */
 196 extern int muxserver_sock;
 197 extern u_int muxclient_command;
 198
 199 /* Prints a help message to the user.  This function never returns. */
 200
 201 static void
 202 usage(void)
 203 {
 204         fprintf(stderr,
 205 "usage: ssh [-1246AaCfGgKkMNnqsTtVvXxYy] [-b bind_address] [-c cipher_spec]\n"
 206 "           [-D [bind_address:]port] [-E log_file] [-e escape_char]\n"
 207 "           [-F configfile] [-I pkcs11] [-i identity_file]\n"
 208 "           [-L address] [-l login_name] [-m mac_spec]\n"
 209 "           [-O ctl_cmd] [-o option] [-p port]\n"
 210 "           [-Q cipher | cipher-auth | mac | kex | key]\n"
 211 "           [-R address] [-S ctl_path] [-W host:port]\n"
 212 "           [-w local_tun[:remote_tun]] [user@]hostname [command]\n"
 213         );
 214         exit(255);
 215 }
 216
 217 static int ssh_session(void);
 218 static int ssh_session2(void);
 219 static void load_public_identity_files(void);
 220 static void main_sigchld_handler(int);
 221
 222 /* from muxclient.c */
 223 void muxclient(const char *);
 224 void muxserver_listen(void);
 225
 226 /* ~/ expand a list of paths. NB. assumes path[n] is heap-allocated. */
 227 static void
 228 tilde_expand_paths(char **paths, u_int num_paths)
 229 {
 230         u_int i;
 231         char *cp;
 232
 233         for (i = 0; i < num_paths; i++) {
 234                 cp = tilde_expand_filename(paths[i], original_real_uid);
 235                 free(paths[i]);
 236                 paths[i] = cp;
 237         }
 238 }
 239
 240 /*
 241  * Attempt to resolve a host name / port to a set of addresses and
 242  * optionally return any CNAMEs encountered along the way.
 243  * Returns NULL on failure.
 244  * NB. this function must operate with a options having undefined members.
 245  */
 246 static struct addrinfo *
 247 resolve_host(const char *name, int port, int logerr, char *cname, size_t clen)
 248 {
 249         char strport[NI_MAXSERV];
 250         struct addrinfo hints, *res;
 251         int gaierr, loglevel = SYSLOG_LEVEL_DEBUG1;
 252
 253         if (port <= 0)
 254                 port = default_ssh_port();
 255
 256         snprintf(strport, sizeof strport, "%u", port);
 257         memset(&hints, 0, sizeof(hints));
 258         hints.ai_family = options.address_family == -1 ?
 259             AF_UNSPEC : options.address_family;
 260         hints.ai_socktype = SOCK_STREAM;
 261         if (cname != NULL)
 262                 hints.ai_flags = AI_CANONNAME;
 263         if ((gaierr = getaddrinfo(name, strport, &hints, &res)) != 0) {
 264                 if (logerr || (gaierr != EAI_NONAME && gaierr != EAI_NODATA))
 265                         loglevel = SYSLOG_LEVEL_ERROR;
 266                 do_log2(loglevel, "%s: Could not resolve hostname %.100s: %s",
 267                     __progname, name, ssh_gai_strerror(gaierr));
 268                 return NULL;
 269         }
 270         if (cname != NULL && res->ai_canonname != NULL) {
 271                 if (strlcpy(cname, res->ai_canonname, clen) >= clen) {
 272                         error("%s: host \"%s\" cname \"%s\" too long (max %lu)",
 273                             __func__, name,  res->ai_canonname, (u_long)clen);
 274                         if (clen > 0)
 275                                 *cname = '\0';
 276                 }
 277         }
 278         return res;
 279 }
 280
 281 /*
 282  * Attempt to resolve a numeric host address / port to a single address.
 283  * Returns a canonical address string.
 284  * Returns NULL on failure.
 285  * NB. this function must operate with a options having undefined members.
 286  */
 287 static struct addrinfo *
 288 resolve_addr(const char *name, int port, char *caddr, size_t clen)
 289 {
 290         char addr[NI_MAXHOST], strport[NI_MAXSERV];
 291         struct addrinfo hints, *res;
 292         int gaierr;
 293
 294         if (port <= 0)
 295                 port = default_ssh_port();
 296         snprintf(strport, sizeof strport, "%u", port);
 297         memset(&hints, 0, sizeof(hints));
 298         hints.ai_family = options.address_family == -1 ?
 299             AF_UNSPEC : options.address_family;
 300         hints.ai_socktype = SOCK_STREAM;
 301         hints.ai_flags = AI_NUMERICHOST|AI_NUMERICSERV;
 302         if ((gaierr = getaddrinfo(name, strport, &hints, &res)) != 0) {
 303                 debug2("%s: could not resolve name %.100s as address: %s",
 304                     __func__, name, ssh_gai_strerror(gaierr));
 305                 return NULL;
 306         }
 307         if (res == NULL) {
 308                 debug("%s: getaddrinfo %.100s returned no addresses",
 309                  __func__, name);
 310                 return NULL;
 311         }
 312         if (res->ai_next != NULL) {
 313                 debug("%s: getaddrinfo %.100s returned multiple addresses",
 314                     __func__, name);
 315                 goto fail;
 316         }
 317         if ((gaierr = getnameinfo(res->ai_addr, res->ai_addrlen,
 318             addr, sizeof(addr), NULL, 0, NI_NUMERICHOST)) != 0) {
 319                 debug("%s: Could not format address for name %.100s: %s",
 320                     __func__, name, ssh_gai_strerror(gaierr));
 321                 goto fail;
 322         }
 323         if (strlcpy(caddr, addr, clen) >= clen) {
 324                 error("%s: host \"%s\" addr \"%s\" too long (max %lu)",
 325                     __func__, name,  addr, (u_long)clen);
 326                 if (clen > 0)
 327                         *caddr = '\0';
 328  fail:
 329                 freeaddrinfo(res);
 330                 return NULL;
 331         }
 332         return res;
 333 }
 334
 335 /*
 336  * Check whether the cname is a permitted replacement for the hostname
 337  * and perform the replacement if it is.
 338  * NB. this function must operate with a options having undefined members.
 339  */
 340 static int
 341 check_follow_cname(char **namep, const char *cname)
 342 {
 343         int i;
 344         struct allowed_cname *rule;
 345
 346         if (*cname == '\0' || options.num_permitted_cnames == 0 ||
 347             strcmp(*namep, cname) == 0)
 348                 return 0;
 349         if (options.canonicalize_hostname == SSH_CANONICALISE_NO)
 350                 return 0;
 351         /*
 352          * Don't attempt to canonicalize names that will be interpreted by
 353          * a proxy unless the user specifically requests so.
 354          */
 355         if (!option_clear_or_none(options.proxy_command) &&
 356             options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS)
 357                 return 0;
 358         debug3("%s: check \"%s\" CNAME \"%s\"", __func__, *namep, cname);
 359         for (i = 0; i < options.num_permitted_cnames; i++) {
 360                 rule = options.permitted_cnames + i;
 361                 if (match_pattern_list(*namep, rule->source_list, 1) != 1 ||
 362                     match_pattern_list(cname, rule->target_list, 1) != 1)
 363                         continue;
 364                 verbose("Canonicalized DNS aliased hostname "
 365                     "\"%s\" => \"%s\"", *namep, cname);
 366                 free(*namep);
 367                 *namep = xstrdup(cname);
 368                 return 1;
 369         }
 370         return 0;
 371 }
 372
 373 /*
 374  * Attempt to resolve the supplied hostname after applying the user's
 375  * canonicalization rules. Returns the address list for the host or NULL
 376  * if no name was found after canonicalization.
 377  * NB. this function must operate with a options having undefined members.
 378  */
 379 static struct addrinfo *
 380 resolve_canonicalize(char **hostp, int port)
 381 {
 382         int i, ndots;
 383         char *cp, *fullhost, newname[NI_MAXHOST];
 384         struct addrinfo *addrs;
 385
 386         if (options.canonicalize_hostname == SSH_CANONICALISE_NO)
 387                 return NULL;
 388
 389         /*
 390          * Don't attempt to canonicalize names that will be interpreted by
 391          * a proxy unless the user specifically requests so.
 392          */
 393         if (!option_clear_or_none(options.proxy_command) &&
 394             options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS)
 395                 return NULL;
 396
 397         /* Try numeric hostnames first */
 398         if ((addrs = resolve_addr(*hostp, port,
 399             newname, sizeof(newname))) != NULL) {
 400                 debug2("%s: hostname %.100s is address", __func__, *hostp);
 401                 if (strcasecmp(*hostp, newname) != 0) {
 402                         debug2("%s: canonicalised address \"%s\" => \"%s\"",
 403                             __func__, *hostp, newname);
 404                         free(*hostp);
 405                         *hostp = xstrdup(newname);
 406                 }
 407                 return addrs;
 408         }
 409
 410         /* Don't apply canonicalization to sufficiently-qualified hostnames */
 411         ndots = 0;
 412         for (cp = *hostp; *cp != '\0'; cp++) {
 413                 if (*cp == '.')
 414                         ndots++;
 415         }
 416         if (ndots > options.canonicalize_max_dots) {
 417                 debug3("%s: not canonicalizing hostname \"%s\" (max dots %d)",
 418                     __func__, *hostp, options.canonicalize_max_dots);
 419                 return NULL;
 420         }
 421         /* Attempt each supplied suffix */
 422         for (i = 0; i < options.num_canonical_domains; i++) {
 423                 *newname = '\0';
 424                 xasprintf(&fullhost, "%s.%s.", *hostp,
 425                     options.canonical_domains[i]);
 426                 debug3("%s: attempting \"%s\" => \"%s\"", __func__,
 427                     *hostp, fullhost);
 428                 if ((addrs = resolve_host(fullhost, port, 0,
 429                     newname, sizeof(newname))) == NULL) {
 430                         free(fullhost);
 431                         continue;
 432                 }
 433                 /* Remove trailing '.' */
 434                 fullhost[strlen(fullhost) - 1] = '\0';
 435                 /* Follow CNAME if requested */
 436                 if (!check_follow_cname(&fullhost, newname)) {
 437                         debug("Canonicalized hostname \"%s\" => \"%s\"",
 438                             *hostp, fullhost);
 439                 }
 440                 free(*hostp);
 441                 *hostp = fullhost;
 442                 return addrs;
 443         }
 444         if (!options.canonicalize_fallback_local)
 445                 fatal("%s: Could not resolve host \"%s\"", __progname, *hostp);
 446         debug2("%s: host %s not found in any suffix", __func__, *hostp);
 447         return NULL;
 448 }
 449
 450 /*
 451  * Read per-user configuration file.  Ignore the system wide config
 452  * file if the user specifies a config file on the command line.
 453  */
 454 static void
 455 process_config_files(const char *host_arg, struct passwd *pw, int post_canon)
 456 {
 457         char buf[PATH_MAX];
 458         int r;
 459
 460         if (config != NULL) {
 461                 if (strcasecmp(config, "none") != 0 &&
 462                     !read_config_file(config, pw, host, host_arg, &options,
 463                     SSHCONF_USERCONF | (post_canon ? SSHCONF_POSTCANON : 0)))
 464                         fatal("Can't open user config file %.100s: "
 465                             "%.100s", config, strerror(errno));
 466         } else {
 467                 r = snprintf(buf, sizeof buf, "%s/%s", pw->pw_dir,
 468                     _PATH_SSH_USER_CONFFILE);
 469                 if (r > 0 && (size_t)r < sizeof(buf))
 470                         (void)read_config_file(buf, pw, host, host_arg,
 471                             &options, SSHCONF_CHECKPERM | SSHCONF_USERCONF |
 472                             (post_canon ? SSHCONF_POSTCANON : 0));
 473
 474                 /* Read systemwide configuration file after user config. */
 475                 (void)read_config_file(_PATH_HOST_CONFIG_FILE, pw,
 476                     host, host_arg, &options,
 477                     post_canon ? SSHCONF_POSTCANON : 0);
 478         }
 479 }
 480
 481 /* Rewrite the port number in an addrinfo list of addresses */
 482 static void
 483 set_addrinfo_port(struct addrinfo *addrs, int port)
 484 {
 485         struct addrinfo *addr;
 486
 487         for (addr = addrs; addr != NULL; addr = addr->ai_next) {
 488                 switch (addr->ai_family) {
 489                 case AF_INET:
 490                         ((struct sockaddr_in *)addr->ai_addr)->
 491                             sin_port = htons(port);
 492                         break;
 493                 case AF_INET6:
 494                         ((struct sockaddr_in6 *)addr->ai_addr)->
 495                             sin6_port = htons(port);
 496                         break;
 497                 }
 498         }
 499 }
 500
 501 /*
 502  * Main program for the ssh client.
 503  */
 504 int
 505 main(int ac, char **av)
 506 {
 507         int i, r, opt, exit_status, use_syslog, config_test = 0;
 508         char *p, *cp, *line, *argv0, buf[PATH_MAX], *host_arg, *logfile;
 509         char thishost[NI_MAXHOST], shorthost[NI_MAXHOST], portstr[NI_MAXSERV];
 510         char cname[NI_MAXHOST];
 511         struct stat st;
 512         struct passwd *pw;
 513         int timeout_ms;
 514         extern int optind, optreset;
 515         extern char *optarg;
 516         struct Forward fwd;
 517         struct addrinfo *addrs = NULL;
 518         struct ssh_digest_ctx *md;
 519         u_char conn_hash[SSH_DIGEST_MAX_LENGTH];
 520         char *conn_hash_hex;
 521
 522         /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
 523         sanitise_stdfd();
 524
 525         __progname = ssh_get_progname(av[0]);
 526
 527 #ifndef HAVE_SETPROCTITLE
 528         /* Prepare for later setproctitle emulation */
 529         /* Save argv so it isn't clobbered by setproctitle() emulation */
 530         saved_av = xcalloc(ac + 1, sizeof(*saved_av));
 531         for (i = 0; i < ac; i++)
 532                 saved_av[i] = xstrdup(av[i]);
 533         saved_av[i] = NULL;
 534         compat_init_setproctitle(ac, av);
 535         av = saved_av;
 536 #endif
 537
 538         /*
 539          * Discard other fds that are hanging around. These can cause problem
 540          * with backgrounded ssh processes started by ControlPersist.
 541          */
 542         closefrom(STDERR_FILENO + 1);
 543
 544         /*
 545          * Save the original real uid.  It will be needed later (uid-swapping
 546          * may clobber the real uid).
 547          */
 548         original_real_uid = getuid();
 549         original_effective_uid = geteuid();
 550
 551         /*
 552          * Use uid-swapping to give up root privileges for the duration of
 553          * option processing.  We will re-instantiate the rights when we are
 554          * ready to create the privileged port, and will permanently drop
 555          * them when the port has been created (actually, when the connection
 556          * has been made, as we may need to create the port several times).
 557          */
 558         PRIV_END;
 559
 560 #ifdef HAVE_SETRLIMIT
 561         /* If we are installed setuid root be careful to not drop core. */
 562         if (original_real_uid != original_effective_uid) {
 563                 struct rlimit rlim;
 564                 rlim.rlim_cur = rlim.rlim_max = 0;
 565                 if (setrlimit(RLIMIT_CORE, &rlim) < 0)
 566                         fatal("setrlimit failed: %.100s", strerror(errno));
 567         }
 568 #endif
 569         /* Get user data. */
 570         pw = getpwuid(original_real_uid);
 571         if (!pw) {
 572                 logit("No user exists for uid %lu", (u_long)original_real_uid);
 573                 exit(255);
 574         }
 575         /* Take a copy of the returned structure. */
 576         pw = pwcopy(pw);
 577
 578         /*
 579          * Set our umask to something reasonable, as some files are created
 580          * with the default umask.  This will make them world-readable but
 581          * writable only by the owner, which is ok for all files for which we
 582          * don't set the modes explicitly.
 583          */
 584         umask(022);
 585
 586         /*
 587          * Initialize option structure to indicate that no values have been
 588          * set.
 589          */
 590         initialize_options(&options);
 591
 592         /* Parse command-line arguments. */
 593         host = NULL;
 594         use_syslog = 0;
 595         logfile = NULL;
 596         argv0 = av[0];
 597
 598  again:
 599         while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx"
 600             "ACD:E:F:GI:KL:MNO:PQ:R:S:TVw:W:XYy")) != -1) {
 601                 switch (opt) {
 602                 case '1':
 603                         options.protocol = SSH_PROTO_1;
 604                         break;
 605                 case '2':
 606                         options.protocol = SSH_PROTO_2;
 607                         break;
 608                 case '4':
 609                         options.address_family = AF_INET;
 610                         break;
 611                 case '6':
 612                         options.address_family = AF_INET6;
 613                         break;
 614                 case 'n':
 615                         stdin_null_flag = 1;
 616                         break;
 617                 case 'f':
 618                         fork_after_authentication_flag = 1;
 619                         stdin_null_flag = 1;
 620                         break;
 621                 case 'x':
 622                         options.forward_x11 = 0;
 623                         break;
 624                 case 'X':
 625                         options.forward_x11 = 1;
 626                         break;
 627                 case 'y':
 628                         use_syslog = 1;
 629                         break;
 630                 case 'E':
 631                         logfile = xstrdup(optarg);
 632                         break;
 633                 case 'G':
 634                         config_test = 1;
 635                         break;
 636                 case 'Y':
 637                         options.forward_x11 = 1;
 638                         options.forward_x11_trusted = 1;
 639                         break;
 640                 case 'g':
 641                         options.fwd_opts.gateway_ports = 1;
 642                         break;
 643                 case 'O':
 644                         if (stdio_forward_host != NULL)
 645                                 fatal("Cannot specify multiplexing "
 646                                     "command with -W");
 647                         else if (muxclient_command != 0)
 648                                 fatal("Multiplexing command already specified");
 649                         if (strcmp(optarg, "check") == 0)
 650                                 muxclient_command = SSHMUX_COMMAND_ALIVE_CHECK;
 651                         else if (strcmp(optarg, "forward") == 0)
 652                                 muxclient_command = SSHMUX_COMMAND_FORWARD;
 653                         else if (strcmp(optarg, "exit") == 0)
 654                                 muxclient_command = SSHMUX_COMMAND_TERMINATE;
 655                         else if (strcmp(optarg, "stop") == 0)
 656                                 muxclient_command = SSHMUX_COMMAND_STOP;
 657                         else if (strcmp(optarg, "cancel") == 0)
 658                                 muxclient_command = SSHMUX_COMMAND_CANCEL_FWD;
 659                         else
 660                                 fatal("Invalid multiplex command.");
 661                         break;
 662                 case 'P':       /* deprecated */
 663                         options.use_privileged_port = 0;
 664                         break;
 665                 case 'Q':
 666                         cp = NULL;
 667                         if (strcmp(optarg, "cipher") == 0)
 668                                 cp = cipher_alg_list('\n', 0);
 669                         else if (strcmp(optarg, "cipher-auth") == 0)
 670                                 cp = cipher_alg_list('\n', 1);
 671                         else if (strcmp(optarg, "mac") == 0)
 672                                 cp = mac_alg_list('\n');
 673                         else if (strcmp(optarg, "kex") == 0)
 674                                 cp = kex_alg_list('\n');
 675                         else if (strcmp(optarg, "key") == 0)
 676                                 cp = key_alg_list(0, 0);
 677                         else if (strcmp(optarg, "key-cert") == 0)
 678                                 cp = key_alg_list(1, 0);
 679                         else if (strcmp(optarg, "key-plain") == 0)
 680                                 cp = key_alg_list(0, 1);
 681                         else if (strcmp(optarg, "protocol-version") == 0) {
 682 #ifdef WITH_SSH1
 683                                 cp = xstrdup("1\n2");
 684 #else
 685                                 cp = xstrdup("2");
 686 #endif
 687                         }
 688                         if (cp == NULL)
 689                                 fatal("Unsupported query \"%s\"", optarg);
 690                         printf("%s\n", cp);
 691                         free(cp);
 692                         exit(0);
 693                         break;
 694                 case 'a':
 695                         options.forward_agent = 0;
 696                         break;
 697                 case 'A':
 698                         options.forward_agent = 1;
 699                         break;
 700                 case 'k':
 701                         options.gss_deleg_creds = 0;
 702                         break;
 703                 case 'K':
 704                         options.gss_authentication = 1;
 705                         options.gss_deleg_creds = 1;
 706                         break;
 707                 case 'i':
 708                         if (stat(optarg, &st) < 0) {
 709                                 fprintf(stderr, "Warning: Identity file %s "
 710                                     "not accessible: %s.\n", optarg,
 711                                     strerror(errno));
 712                                 break;
 713                         }
 714                         add_identity_file(&options, NULL, optarg, 1);
 715                         break;
 716                 case 'I':
 717 #ifdef ENABLE_PKCS11
 718                         options.pkcs11_provider = xstrdup(optarg);
 719 #else
 720                         fprintf(stderr, "no support for PKCS#11.\n");
 721 #endif
 722                         break;
 723                 case 't':
 724                         if (options.request_tty == REQUEST_TTY_YES)
 725                                 options.request_tty = REQUEST_TTY_FORCE;
 726                         else
 727                                 options.request_tty = REQUEST_TTY_YES;
 728                         break;
 729                 case 'v':
 730                         if (debug_flag == 0) {
 731                                 debug_flag = 1;
 732                                 options.log_level = SYSLOG_LEVEL_DEBUG1;
 733                         } else {
 734                                 if (options.log_level < SYSLOG_LEVEL_DEBUG3)
 735                                         options.log_level++;
 736                         }
 737                         break;
 738                 case 'V':
 739                         if (options.version_addendum &&
 740                             *options.version_addendum != '\0')
 741                                 fprintf(stderr, "%s %s, %s\n", SSH_RELEASE,
 742                                     options.version_addendum,
 743                                     OPENSSL_VERSION);
 744                         else
 745                                 fprintf(stderr, "%s, %s\n", SSH_RELEASE,
 746                                     OPENSSL_VERSION);
 747                         if (opt == 'V')
 748                                 exit(0);
 749                         break;
 750                 case 'w':
 751                         if (options.tun_open == -1)
 752                                 options.tun_open = SSH_TUNMODE_DEFAULT;
 753                         options.tun_local = a2tun(optarg, &options.tun_remote);
 754                         if (options.tun_local == SSH_TUNID_ERR) {
 755                                 fprintf(stderr,
 756                                     "Bad tun device '%s'\n", optarg);
 757                                 exit(255);
 758                         }
 759                         break;
 760                 case 'W':
 761                         if (stdio_forward_host != NULL)
 762                                 fatal("stdio forward already specified");
 763                         if (muxclient_command != 0)
 764                                 fatal("Cannot specify stdio forward with -O");
 765                         if (parse_forward(&fwd, optarg, 1, 0)) {
 766                                 stdio_forward_host = fwd.listen_host;
 767                                 stdio_forward_port = fwd.listen_port;
 768                                 free(fwd.connect_host);
 769                         } else {
 770                                 fprintf(stderr,
 771                                     "Bad stdio forwarding specification '%s'\n",
 772                                     optarg);
 773                                 exit(255);
 774                         }
 775                         options.request_tty = REQUEST_TTY_NO;
 776                         no_shell_flag = 1;
 777                         options.clear_forwardings = 1;
 778                         options.exit_on_forward_failure = 1;
 779                         break;
 780                 case 'q':
 781                         options.log_level = SYSLOG_LEVEL_QUIET;
 782                         break;
 783                 case 'e':
 784                         if (optarg[0] == '^' && optarg[2] == 0 &&
 785                             (u_char) optarg[1] >= 64 &&
 786                             (u_char) optarg[1] < 128)
 787                                 options.escape_char = (u_char) optarg[1] & 31;
 788                         else if (strlen(optarg) == 1)
 789                                 options.escape_char = (u_char) optarg[0];
 790                         else if (strcmp(optarg, "none") == 0)
 791                                 options.escape_char = SSH_ESCAPECHAR_NONE;
 792                         else {
 793                                 fprintf(stderr, "Bad escape character '%s'.\n",
 794                                     optarg);
 795                                 exit(255);
 796                         }
 797                         break;
 798                 case 'c':
 799                         if (ciphers_valid(*optarg == '+' ?
 800                             optarg + 1 : optarg)) {
 801                                 /* SSH2 only */
 802                                 options.ciphers = xstrdup(optarg);
 803                                 options.cipher = SSH_CIPHER_INVALID;
 804                                 break;
 805                         }
 806                         /* SSH1 only */
 807                         options.cipher = cipher_number(optarg);
 808                         if (options.cipher == -1) {
 809                                 fprintf(stderr, "Unknown cipher type '%s'\n",
 810                                     optarg);
 811                                 exit(255);
 812                         }
 813                         if (options.cipher == SSH_CIPHER_3DES)
 814                                 options.ciphers = xstrdup("3des-cbc");
 815                         else if (options.cipher == SSH_CIPHER_BLOWFISH)
 816                                 options.ciphers = xstrdup("blowfish-cbc");
 817                         else
 818                                 options.ciphers = xstrdup(KEX_CLIENT_ENCRYPT);
 819                         break;
 820                 case 'm':
 821                         if (mac_valid(optarg))
 822                                 options.macs = xstrdup(optarg);
 823                         else {
 824                                 fprintf(stderr, "Unknown mac type '%s'\n",
 825                                     optarg);
 826                                 exit(255);
 827                         }
 828                         break;
 829                 case 'M':
 830                         if (options.control_master == SSHCTL_MASTER_YES)
 831                                 options.control_master = SSHCTL_MASTER_ASK;
 832                         else
 833                                 options.control_master = SSHCTL_MASTER_YES;
 834                         break;
 835                 case 'p':
 836                         options.port = a2port(optarg);
 837                         if (options.port <= 0) {
 838                                 fprintf(stderr, "Bad port '%s'\n", optarg);
 839                                 exit(255);
 840                         }
 841                         break;
 842                 case 'l':
 843                         options.user = optarg;
 844                         break;
 845
 846                 case 'L':
 847                         if (parse_forward(&fwd, optarg, 0, 0))
 848                                 add_local_forward(&options, &fwd);
 849                         else {
 850                                 fprintf(stderr,
 851                                     "Bad local forwarding specification '%s'\n",
 852                                     optarg);
 853                                 exit(255);
 854                         }
 855                         break;
 856
 857                 case 'R':
 858                         if (parse_forward(&fwd, optarg, 0, 1)) {
 859                                 add_remote_forward(&options, &fwd);
 860                         } else {
 861                                 fprintf(stderr,
 862                                     "Bad remote forwarding specification "
 863                                     "'%s'\n", optarg);
 864                                 exit(255);
 865                         }
 866                         break;
 867
 868                 case 'D':
 869                         if (parse_forward(&fwd, optarg, 1, 0)) {
 870                                 add_local_forward(&options, &fwd);
 871                         } else {
 872                                 fprintf(stderr,
 873                                     "Bad dynamic forwarding specification "
 874                                     "'%s'\n", optarg);
 875                                 exit(255);
 876                         }
 877                         break;
 878
 879                 case 'C':
 880                         options.compression = 1;
 881                         break;
 882                 case 'N':
 883                         no_shell_flag = 1;
 884                         options.request_tty = REQUEST_TTY_NO;
 885                         break;
 886                 case 'T':
 887                         options.request_tty = REQUEST_TTY_NO;
 888                         break;
 889                 case 'o':
 890                         line = xstrdup(optarg);
 891                         if (process_config_line(&options, pw,
 892                             host ? host : "", host ? host : "", line,
 893                             "command-line", 0, NULL, SSHCONF_USERCONF) != 0)
 894                                 exit(255);
 895                         free(line);
 896                         break;
 897                 case 's':
 898                         subsystem_flag = 1;
 899                         break;
 900                 case 'S':
 901                         if (options.control_path != NULL)
 902                                 free(options.control_path);
 903                         options.control_path = xstrdup(optarg);
 904                         break;
 905                 case 'b':
 906                         options.bind_address = optarg;
 907                         break;
 908                 case 'F':
 909                         config = optarg;
 910                         break;
 911                 default:
 912                         usage();
 913                 }
 914         }
 915
 916         ac -= optind;
 917         av += optind;
 918
 919         if (ac > 0 && !host) {
 920                 if (strrchr(*av, '@')) {
 921                         p = xstrdup(*av);
 922                         cp = strrchr(p, '@');
 923                         if (cp == NULL || cp == p)
 924                                 usage();
 925                         options.user = p;
 926                         *cp = '\0';
 927                         host = xstrdup(++cp);
 928                 } else
 929                         host = xstrdup(*av);
 930                 if (ac > 1) {
 931                         optind = optreset = 1;
 932                         goto again;
 933                 }
 934                 ac--, av++;
 935         }
 936
 937         /* Check that we got a host name. */
 938         if (!host)
 939                 usage();
 940
 941         host_arg = xstrdup(host);
 942
 943 #ifdef WITH_OPENSSL
 944         OpenSSL_add_all_algorithms();
 945         ERR_load_crypto_strings();
 946 #endif
 947
 948         /* Initialize the command to execute on remote host. */
 949         buffer_init(&command);
 950
 951         /*
 952          * Save the command to execute on the remote host in a buffer. There
 953          * is no limit on the length of the command, except by the maximum
 954          * packet size.  Also sets the tty flag if there is no command.
 955          */
 956         if (!ac) {
 957                 /* No command specified - execute shell on a tty. */
 958                 if (subsystem_flag) {
 959                         fprintf(stderr,
 960                             "You must specify a subsystem to invoke.\n");
 961                         usage();
 962                 }
 963         } else {
 964                 /* A command has been specified.  Store it into the buffer. */
 965                 for (i = 0; i < ac; i++) {
 966                         if (i)
 967                                 buffer_append(&command, " ", 1);
 968                         buffer_append(&command, av[i], strlen(av[i]));
 969                 }
 970         }
 971
 972         /* Cannot fork to background if no command. */
 973         if (fork_after_authentication_flag && buffer_len(&command) == 0 &&
 974             !no_shell_flag)
 975                 fatal("Cannot fork into background without a command "
 976                     "to execute.");
 977
 978         /*
 979          * Initialize "log" output.  Since we are the client all output
 980          * goes to stderr unless otherwise specified by -y or -E.
 981          */
 982         if (use_syslog && logfile != NULL)
 983                 fatal("Can't specify both -y and -E");
 984         if (logfile != NULL) {
 985                 log_redirect_stderr_to(logfile);
 986                 free(logfile);
 987         }
 988         log_init(argv0,
 989             options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level,
 990             SYSLOG_FACILITY_USER, !use_syslog);
 991
 992         if (debug_flag)
 993                 /* version_addendum is always NULL at this point */
 994                 logit("%s, %s", SSH_RELEASE, OPENSSL_VERSION);
 995
 996         /* Parse the configuration files */
 997         process_config_files(host_arg, pw, 0);
 998
 999         /* Hostname canonicalisation needs a few options filled. */
1000         fill_default_options_for_canonicalization(&options);
1001
1002         /* If the user has replaced the hostname then take it into use now */
1003         if (options.hostname != NULL) {
1004                 /* NB. Please keep in sync with readconf.c:match_cfg_line() */
1005                 cp = percent_expand(options.hostname,
1006                     "h", host, (char *)NULL);
1007                 free(host);
1008                 host = cp;
1009                 free(options.hostname);
1010                 options.hostname = xstrdup(host);
1011         }
1012
1013         /* If canonicalization requested then try to apply it */
1014         lowercase(host);
1015         if (options.canonicalize_hostname != SSH_CANONICALISE_NO)
1016                 addrs = resolve_canonicalize(&host, options.port);
1017
1018         /*
1019          * If CanonicalizePermittedCNAMEs have been specified but
1020          * other canonicalization did not happen (by not being requested
1021          * or by failing with fallback) then the hostname may still be changed
1022          * as a result of CNAME following.
1023          *
1024          * Try to resolve the bare hostname name using the system resolver's
1025          * usual search rules and then apply the CNAME follow rules.
1026          *
1027          * Skip the lookup if a ProxyCommand is being used unless the user
1028          * has specifically requested canonicalisation for this case via
1029          * CanonicalizeHostname=always
1030          */
1031         if (addrs == NULL && options.num_permitted_cnames != 0 &&
1032             (option_clear_or_none(options.proxy_command) ||
1033             options.canonicalize_hostname == SSH_CANONICALISE_ALWAYS)) {
1034                 if ((addrs = resolve_host(host, options.port,
1035                     option_clear_or_none(options.proxy_command),
1036                     cname, sizeof(cname))) == NULL) {
1037                         /* Don't fatal proxied host names not in the DNS */
1038                         if (option_clear_or_none(options.proxy_command))
1039                                 cleanup_exit(255); /* logged in resolve_host */
1040                 } else
1041                         check_follow_cname(&host, cname);
1042         }
1043
1044         /*
1045          * If canonicalisation is enabled then re-parse the configuration
1046          * files as new stanzas may match.
1047          */
1048         if (options.canonicalize_hostname != 0) {
1049                 debug("Re-reading configuration after hostname "
1050                     "canonicalisation");
1051                 free(options.hostname);
1052                 options.hostname = xstrdup(host);
1053                 process_config_files(host_arg, pw, 1);
1054                 /*
1055                  * Address resolution happens early with canonicalisation
1056                  * enabled and the port number may have changed since, so
1057                  * reset it in address list
1058                  */
1059                 if (addrs != NULL && options.port > 0)
1060                         set_addrinfo_port(addrs, options.port);
1061         }
1062
1063         /* Fill configuration defaults. */
1064         fill_default_options(&options);
1065
1066         if (options.port == 0)
1067                 options.port = default_ssh_port();
1068         channel_set_af(options.address_family);
1069
1070         /* Tidy and check options */
1071         if (options.host_key_alias != NULL)
1072                 lowercase(options.host_key_alias);
1073         if (options.proxy_command != NULL &&
1074             strcmp(options.proxy_command, "-") == 0 &&
1075             options.proxy_use_fdpass)
1076                 fatal("ProxyCommand=- and ProxyUseFDPass are incompatible");
1077         if (options.control_persist &&
1078             options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK) {
1079                 debug("UpdateHostKeys=ask is incompatible with ControlPersist; "
1080                     "disabling");
1081                 options.update_hostkeys = 0;
1082         }
1083 #ifndef HAVE_CYGWIN
1084         if (original_effective_uid != 0)
1085                 options.use_privileged_port = 0;
1086 #endif
1087
1088         /* reinit */
1089         log_init(argv0, options.log_level, SYSLOG_FACILITY_USER, !use_syslog);
1090
1091         if (options.request_tty == REQUEST_TTY_YES ||
1092             options.request_tty == REQUEST_TTY_FORCE)
1093                 tty_flag = 1;
1094
1095         /* Allocate a tty by default if no command specified. */
1096         if (buffer_len(&command) == 0)
1097                 tty_flag = options.request_tty != REQUEST_TTY_NO;
1098
1099         /* Force no tty */
1100         if (options.request_tty == REQUEST_TTY_NO || muxclient_command != 0)
1101                 tty_flag = 0;
1102         /* Do not allocate a tty if stdin is not a tty. */
1103         if ((!isatty(fileno(stdin)) || stdin_null_flag) &&
1104             options.request_tty != REQUEST_TTY_FORCE) {
1105                 if (tty_flag)
1106                         logit("Pseudo-terminal will not be allocated because "
1107                             "stdin is not a terminal.");
1108                 tty_flag = 0;
1109         }
1110
1111         seed_rng();
1112
1113         if (options.user == NULL)
1114                 options.user = xstrdup(pw->pw_name);
1115
1116         if (gethostname(thishost, sizeof(thishost)) == -1)
1117                 fatal("gethostname: %s", strerror(errno));
1118         strlcpy(shorthost, thishost, sizeof(shorthost));
1119         shorthost[strcspn(thishost, ".")] = '\0';
1120         snprintf(portstr, sizeof(portstr), "%d", options.port);
1121
1122         /* Find canonic host name. */
1123         if (strchr(host, '.') == 0) {
1124                 struct addrinfo hints;
1125                 struct addrinfo *ai = NULL;
1126                 int errgai;
1127                 memset(&hints, 0, sizeof(hints));
1128                 hints.ai_family = options.address_family;
1129                 hints.ai_flags = AI_CANONNAME;
1130                 hints.ai_socktype = SOCK_STREAM;
1131                 errgai = getaddrinfo(host, NULL, &hints, &ai);
1132                 if (errgai == 0) {
1133                         if (ai->ai_canonname != NULL)
1134                                 host = xstrdup(ai->ai_canonname);
1135                         freeaddrinfo(ai);
1136                 }
1137         }
1138
1139         if ((md = ssh_digest_start(SSH_DIGEST_SHA1)) == NULL ||
1140             ssh_digest_update(md, thishost, strlen(thishost)) < 0 ||
1141             ssh_digest_update(md, host, strlen(host)) < 0 ||
1142             ssh_digest_update(md, portstr, strlen(portstr)) < 0 ||
1143             ssh_digest_update(md, options.user, strlen(options.user)) < 0 ||
1144             ssh_digest_final(md, conn_hash, sizeof(conn_hash)) < 0)
1145                 fatal("%s: mux digest failed", __func__);
1146         ssh_digest_free(md);
1147         conn_hash_hex = tohex(conn_hash, ssh_digest_bytes(SSH_DIGEST_SHA1));
1148
1149         if (options.local_command != NULL) {
1150                 debug3("expanding LocalCommand: %s", options.local_command);
1151                 cp = options.local_command;
1152                 options.local_command = percent_expand(cp,
1153                     "C", conn_hash_hex,
1154                     "L", shorthost,
1155                     "d", pw->pw_dir,
1156                     "h", host,
1157                     "l", thishost,
1158                     "n", host_arg,
1159                     "p", portstr,
1160                     "r", options.user,
1161                     "u", pw->pw_name,
1162                     (char *)NULL);
1163                 debug3("expanded LocalCommand: %s", options.local_command);
1164                 free(cp);
1165         }
1166
1167         if (options.control_path != NULL) {
1168                 cp = tilde_expand_filename(options.control_path,
1169                     original_real_uid);
1170                 free(options.control_path);
1171                 options.control_path = percent_expand(cp,
1172                     "C", conn_hash_hex,
1173                     "L", shorthost,
1174                     "h", host,
1175                     "l", thishost,
1176                     "n", host_arg,
1177                     "p", portstr,
1178                     "r", options.user,
1179                     "u", pw->pw_name,
1180                     (char *)NULL);
1181                 free(cp);
1182         }
1183         free(conn_hash_hex);
1184
1185         if (config_test) {
1186                 dump_client_config(&options, host);
1187                 exit(0);
1188         }
1189
1190         if (muxclient_command != 0 && options.control_path == NULL)
1191                 fatal("No ControlPath specified for \"-O\" command");
1192         if (options.control_path != NULL)
1193                 muxclient(options.control_path);
1194
1195         /*
1196          * If hostname canonicalisation was not enabled, then we may not
1197          * have yet resolved the hostname. Do so now.
1198          */
1199         if (addrs == NULL && options.proxy_command == NULL) {
1200                 if ((addrs = resolve_host(host, options.port, 1,
1201                     cname, sizeof(cname))) == NULL)
1202                         cleanup_exit(255); /* resolve_host logs the error */
1203         }
1204
1205         timeout_ms = options.connection_timeout * 1000;
1206
1207         /* Open a connection to the remote host. */
1208         if (ssh_connect(host, addrs, &hostaddr, options.port,
1209             options.address_family, options.connection_attempts,
1210             &timeout_ms, options.tcp_keep_alive,
1211             options.use_privileged_port) != 0)
1212                 exit(255);
1213
1214         if (addrs != NULL)
1215                 freeaddrinfo(addrs);
1216
1217         packet_set_timeout(options.server_alive_interval,
1218             options.server_alive_count_max);
1219
1220         if (timeout_ms > 0)
1221                 debug3("timeout: %d ms remain after connect", timeout_ms);
1222
1223         /*
1224          * If we successfully made the connection, load the host private key
1225          * in case we will need it later for combined rsa-rhosts
1226          * authentication. This must be done before releasing extra
1227          * privileges, because the file is only readable by root.
1228          * If we cannot access the private keys, load the public keys
1229          * instead and try to execute the ssh-keysign helper instead.
1230          */
1231         sensitive_data.nkeys = 0;
1232         sensitive_data.keys = NULL;
1233         sensitive_data.external_keysign = 0;
1234         if (options.rhosts_rsa_authentication ||
1235             options.hostbased_authentication) {
1236                 sensitive_data.nkeys = 9;
1237                 sensitive_data.keys = xcalloc(sensitive_data.nkeys,
1238                     sizeof(Key));
1239                 for (i = 0; i < sensitive_data.nkeys; i++)
1240                         sensitive_data.keys[i] = NULL;
1241
1242                 PRIV_START;
1243                 sensitive_data.keys[0] = key_load_private_type(KEY_RSA1,
1244                     _PATH_HOST_KEY_FILE, "", NULL, NULL);
1245 #ifdef OPENSSL_HAS_ECC
1246                 sensitive_data.keys[1] = key_load_private_cert(KEY_ECDSA,
1247                     _PATH_HOST_ECDSA_KEY_FILE, "", NULL);
1248 #endif
1249                 sensitive_data.keys[2] = key_load_private_cert(KEY_ED25519,
1250                     _PATH_HOST_ED25519_KEY_FILE, "", NULL);
1251                 sensitive_data.keys[3] = key_load_private_cert(KEY_RSA,
1252                     _PATH_HOST_RSA_KEY_FILE, "", NULL);
1253                 sensitive_data.keys[4] = key_load_private_cert(KEY_DSA,
1254                     _PATH_HOST_DSA_KEY_FILE, "", NULL);
1255 #ifdef OPENSSL_HAS_ECC
1256                 sensitive_data.keys[5] = key_load_private_type(KEY_ECDSA,
1257                     _PATH_HOST_ECDSA_KEY_FILE, "", NULL, NULL);
1258 #endif
1259                 sensitive_data.keys[6] = key_load_private_type(KEY_ED25519,
1260                     _PATH_HOST_ED25519_KEY_FILE, "", NULL, NULL);
1261                 sensitive_data.keys[7] = key_load_private_type(KEY_RSA,
1262                     _PATH_HOST_RSA_KEY_FILE, "", NULL, NULL);
1263                 sensitive_data.keys[8] = key_load_private_type(KEY_DSA,
1264                     _PATH_HOST_DSA_KEY_FILE, "", NULL, NULL);
1265                 PRIV_END;
1266
1267                 if (options.hostbased_authentication == 1 &&
1268                     sensitive_data.keys[0] == NULL &&
1269                     sensitive_data.keys[5] == NULL &&
1270                     sensitive_data.keys[6] == NULL &&
1271                     sensitive_data.keys[7] == NULL &&
1272                     sensitive_data.keys[8] == NULL) {
1273 #ifdef OPENSSL_HAS_ECC
1274                         sensitive_data.keys[1] = key_load_cert(
1275                             _PATH_HOST_ECDSA_KEY_FILE);
1276 #endif
1277                         sensitive_data.keys[2] = key_load_cert(
1278                             _PATH_HOST_ED25519_KEY_FILE);
1279                         sensitive_data.keys[3] = key_load_cert(
1280                             _PATH_HOST_RSA_KEY_FILE);
1281                         sensitive_data.keys[4] = key_load_cert(
1282                             _PATH_HOST_DSA_KEY_FILE);
1283 #ifdef OPENSSL_HAS_ECC
1284                         sensitive_data.keys[5] = key_load_public(
1285                             _PATH_HOST_ECDSA_KEY_FILE, NULL);
1286 #endif
1287                         sensitive_data.keys[6] = key_load_public(
1288                             _PATH_HOST_ED25519_KEY_FILE, NULL);
1289                         sensitive_data.keys[7] = key_load_public(
1290                             _PATH_HOST_RSA_KEY_FILE, NULL);
1291                         sensitive_data.keys[8] = key_load_public(
1292                             _PATH_HOST_DSA_KEY_FILE, NULL);
1293                         sensitive_data.external_keysign = 1;
1294                 }
1295         }
1296         /*
1297          * Get rid of any extra privileges that we may have.  We will no
1298          * longer need them.  Also, extra privileges could make it very hard
1299          * to read identity files and other non-world-readable files from the
1300          * user's home directory if it happens to be on a NFS volume where
1301          * root is mapped to nobody.
1302          */
1303         if (original_effective_uid == 0) {
1304                 PRIV_START;
1305                 permanently_set_uid(pw);
1306         }
1307
1308         /*
1309          * Now that we are back to our own permissions, create ~/.ssh
1310          * directory if it doesn't already exist.
1311          */
1312         if (config == NULL) {
1313                 r = snprintf(buf, sizeof buf, "%s%s%s", pw->pw_dir,
1314                     strcmp(pw->pw_dir, "/") ? "/" : "", _PATH_SSH_USER_DIR);
1315                 if (r > 0 && (size_t)r < sizeof(buf) && stat(buf, &st) < 0) {
1316 #ifdef WITH_SELINUX
1317                         ssh_selinux_setfscreatecon(buf);
1318 #endif
1319                         if (mkdir(buf, 0700) < 0)
1320                                 error("Could not create directory '%.200s'.",
1321                                     buf);
1322 #ifdef WITH_SELINUX
1323                         ssh_selinux_setfscreatecon(NULL);
1324 #endif
1325                 }
1326         }
1327         /* load options.identity_files */
1328         load_public_identity_files();
1329
1330         /* Expand ~ in known host file names. */
1331         tilde_expand_paths(options.system_hostfiles,
1332             options.num_system_hostfiles);
1333         tilde_expand_paths(options.user_hostfiles, options.num_user_hostfiles);
1334
1335         signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */
1336         signal(SIGCHLD, main_sigchld_handler);
1337
1338         /* Log into the remote system.  Never returns if the login fails. */
1339         ssh_login(&sensitive_data, host, (struct sockaddr *)&hostaddr,
1340             options.port, pw, timeout_ms);
1341
1342         if (packet_connection_is_on_socket()) {
1343                 verbose("Authenticated to %s ([%s]:%d).", host,
1344                     get_remote_ipaddr(), get_remote_port());
1345         } else {
1346                 verbose("Authenticated to %s (via proxy).", host);
1347         }
1348
1349         /* We no longer need the private host keys.  Clear them now. */
1350         if (sensitive_data.nkeys != 0) {
1351                 for (i = 0; i < sensitive_data.nkeys; i++) {
1352                         if (sensitive_data.keys[i] != NULL) {
1353                                 /* Destroys contents safely */
1354                                 debug3("clear hostkey %d", i);
1355                                 key_free(sensitive_data.keys[i]);
1356                                 sensitive_data.keys[i] = NULL;
1357                         }
1358                 }
1359                 free(sensitive_data.keys);
1360         }
1361         for (i = 0; i < options.num_identity_files; i++) {
1362                 free(options.identity_files[i]);
1363                 options.identity_files[i] = NULL;
1364                 if (options.identity_keys[i]) {
1365                         key_free(options.identity_keys[i]);
1366                         options.identity_keys[i] = NULL;
1367                 }
1368         }
1369
1370         exit_status = compat20 ? ssh_session2() : ssh_session();
1371         packet_close();
1372
1373         if (options.control_path != NULL && muxserver_sock != -1)
1374                 unlink(options.control_path);
1375
1376         /* Kill ProxyCommand if it is running. */
1377         ssh_kill_proxy_command();
1378
1379         return exit_status;
1380 }
1381
1382 static void
1383 control_persist_detach(void)
1384 {
1385         pid_t pid;
1386         int devnull;
1387
1388         debug("%s: backgrounding master process", __func__);
1389
1390         /*
1391          * master (current process) into the background, and make the
1392          * foreground process a client of the backgrounded master.
1393          */
1394         switch ((pid = fork())) {
1395         case -1:
1396                 fatal("%s: fork: %s", __func__, strerror(errno));
1397         case 0:
1398                 /* Child: master process continues mainloop */
1399                 break;
1400         default:
1401                 /* Parent: set up mux slave to connect to backgrounded master */
1402                 debug2("%s: background process is %ld", __func__, (long)pid);
1403                 stdin_null_flag = ostdin_null_flag;
1404                 options.request_tty = orequest_tty;
1405                 tty_flag = otty_flag;
1406                 close(muxserver_sock);
1407                 muxserver_sock = -1;
1408                 options.control_master = SSHCTL_MASTER_NO;
1409                 muxclient(options.control_path);
1410                 /* muxclient() doesn't return on success. */
1411                 fatal("Failed to connect to new control master");
1412         }
1413         if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1) {
1414                 error("%s: open(\"/dev/null\"): %s", __func__,
1415                     strerror(errno));
1416         } else {
1417                 if (dup2(devnull, STDIN_FILENO) == -1 ||
1418                     dup2(devnull, STDOUT_FILENO) == -1)
1419                         error("%s: dup2: %s", __func__, strerror(errno));
1420                 if (devnull > STDERR_FILENO)
1421                         close(devnull);
1422         }
1423         daemon(1, 1);
1424         setproctitle("%s [mux]", options.control_path);
1425 }
1426
1427 /* Do fork() after authentication. Used by "ssh -f" */
1428 static void
1429 fork_postauth(void)
1430 {
1431         if (need_controlpersist_detach)
1432                 control_persist_detach();
1433         debug("forking to background");
1434         fork_after_authentication_flag = 0;
1435         if (daemon(1, 1) < 0)
1436                 fatal("daemon() failed: %.200s", strerror(errno));
1437 }
1438
1439 /* Callback for remote forward global requests */
1440 static void
1441 ssh_confirm_remote_forward(int type, u_int32_t seq, void *ctxt)
1442 {
1443         struct Forward *rfwd = (struct Forward *)ctxt;
1444
1445         /* XXX verbose() on failure? */
1446         debug("remote forward %s for: listen %s%s%d, connect %s:%d",
1447             type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure",
1448             rfwd->listen_path ? rfwd->listen_path :
1449             rfwd->listen_host ? rfwd->listen_host : "",
1450             (rfwd->listen_path || rfwd->listen_host) ? ":" : "",
1451             rfwd->listen_port, rfwd->connect_path ? rfwd->connect_path :
1452             rfwd->connect_host, rfwd->connect_port);
1453         if (rfwd->listen_path == NULL && rfwd->listen_port == 0) {
1454                 if (type == SSH2_MSG_REQUEST_SUCCESS) {
1455                         rfwd->allocated_port = packet_get_int();
1456                         logit("Allocated port %u for remote forward to %s:%d",
1457                             rfwd->allocated_port,
1458                             rfwd->connect_host, rfwd->connect_port);
1459                         channel_update_permitted_opens(rfwd->handle,
1460                             rfwd->allocated_port);
1461                 } else {
1462                         channel_update_permitted_opens(rfwd->handle, -1);
1463                 }
1464         }
1465
1466         if (type == SSH2_MSG_REQUEST_FAILURE) {
1467                 if (options.exit_on_forward_failure) {
1468                         if (rfwd->listen_path != NULL)
1469                                 fatal("Error: remote port forwarding failed "
1470                                     "for listen path %s", rfwd->listen_path);
1471                         else
1472                                 fatal("Error: remote port forwarding failed "
1473                                     "for listen port %d", rfwd->listen_port);
1474                 } else {
1475                         if (rfwd->listen_path != NULL)
1476                                 logit("Warning: remote port forwarding failed "
1477                                     "for listen path %s", rfwd->listen_path);
1478                         else
1479                                 logit("Warning: remote port forwarding failed "
1480                                     "for listen port %d", rfwd->listen_port);
1481                 }
1482         }
1483         if (++remote_forward_confirms_received == options.num_remote_forwards) {
1484                 debug("All remote forwarding requests processed");
1485                 if (fork_after_authentication_flag)
1486                         fork_postauth();
1487         }
1488 }
1489
1490 static void
1491 client_cleanup_stdio_fwd(int id, void *arg)
1492 {
1493         debug("stdio forwarding: done");
1494         cleanup_exit(0);
1495 }
1496
1497 static void
1498 ssh_stdio_confirm(int id, int success, void *arg)
1499 {
1500         if (!success)
1501                 fatal("stdio forwarding failed");
1502 }
1503
1504 static void
1505 ssh_init_stdio_forwarding(void)
1506 {
1507         Channel *c;
1508         int in, out;
1509
1510         if (stdio_forward_host == NULL)
1511                 return;
1512         if (!compat20)
1513                 fatal("stdio forwarding require Protocol 2");
1514
1515         debug3("%s: %s:%d", __func__, stdio_forward_host, stdio_forward_port);
1516
1517         if ((in = dup(STDIN_FILENO)) < 0 ||
1518             (out = dup(STDOUT_FILENO)) < 0)
1519                 fatal("channel_connect_stdio_fwd: dup() in/out failed");
1520         if ((c = channel_connect_stdio_fwd(stdio_forward_host,
1521             stdio_forward_port, in, out)) == NULL)
1522                 fatal("%s: channel_connect_stdio_fwd failed", __func__);
1523         channel_register_cleanup(c->self, client_cleanup_stdio_fwd, 0);
1524         channel_register_open_confirm(c->self, ssh_stdio_confirm, NULL);
1525 }
1526
1527 static void
1528 ssh_init_forwarding(void)
1529 {
1530         int success = 0;
1531         int i;
1532
1533         /* Initiate local TCP/IP port forwardings. */
1534         for (i = 0; i < options.num_local_forwards; i++) {
1535                 debug("Local connections to %.200s:%d forwarded to remote "
1536                     "address %.200s:%d",
1537                     (options.local_forwards[i].listen_path != NULL) ?
1538                     options.local_forwards[i].listen_path :
1539                     (options.local_forwards[i].listen_host == NULL) ?
1540                     (options.fwd_opts.gateway_ports ? "*" : "LOCALHOST") :
1541                     options.local_forwards[i].listen_host,
1542                     options.local_forwards[i].listen_port,
1543                     (options.local_forwards[i].connect_path != NULL) ?
1544                     options.local_forwards[i].connect_path :
1545                     options.local_forwards[i].connect_host,
1546                     options.local_forwards[i].connect_port);
1547                 success += channel_setup_local_fwd_listener(
1548                     &options.local_forwards[i], &options.fwd_opts);
1549         }
1550         if (i > 0 && success != i && options.exit_on_forward_failure)
1551                 fatal("Could not request local forwarding.");
1552         if (i > 0 && success == 0)
1553                 error("Could not request local forwarding.");
1554
1555         /* Initiate remote TCP/IP port forwardings. */
1556         for (i = 0; i < options.num_remote_forwards; i++) {
1557                 debug("Remote connections from %.200s:%d forwarded to "
1558                     "local address %.200s:%d",
1559                     (options.remote_forwards[i].listen_path != NULL) ?
1560                     options.remote_forwards[i].listen_path :
1561                     (options.remote_forwards[i].listen_host == NULL) ?
1562                     "LOCALHOST" : options.remote_forwards[i].listen_host,
1563                     options.remote_forwards[i].listen_port,
1564                     (options.remote_forwards[i].connect_path != NULL) ?
1565                     options.remote_forwards[i].connect_path :
1566                     options.remote_forwards[i].connect_host,
1567                     options.remote_forwards[i].connect_port);
1568                 options.remote_forwards[i].handle =
1569                     channel_request_remote_forwarding(
1570                     &options.remote_forwards[i]);
1571                 if (options.remote_forwards[i].handle < 0) {
1572                         if (options.exit_on_forward_failure)
1573                                 fatal("Could not request remote forwarding.");
1574                         else
1575                                 logit("Warning: Could not request remote "
1576                                     "forwarding.");
1577                 } else {
1578                         client_register_global_confirm(ssh_confirm_remote_forward,
1579                             &options.remote_forwards[i]);
1580                 }
1581         }
1582
1583         /* Initiate tunnel forwarding. */
1584         if (options.tun_open != SSH_TUNMODE_NO) {
1585                 if (client_request_tun_fwd(options.tun_open,
1586                     options.tun_local, options.tun_remote) == -1) {
1587                         if (options.exit_on_forward_failure)
1588                                 fatal("Could not request tunnel forwarding.");
1589                         else
1590                                 error("Could not request tunnel forwarding.");
1591                 }
1592         }
1593 }
1594
1595 static void
1596 check_agent_present(void)
1597 {
1598         int r;
1599
1600         if (options.forward_agent) {
1601                 /* Clear agent forwarding if we don't have an agent. */
1602                 if ((r = ssh_get_authentication_socket(NULL)) != 0) {
1603                         options.forward_agent = 0;
1604                         if (r != SSH_ERR_AGENT_NOT_PRESENT)
1605                                 debug("ssh_get_authentication_socket: %s",
1606                                     ssh_err(r));
1607                 }
1608         }
1609 }
1610
1611 static int
1612 ssh_session(void)
1613 {
1614         int type;
1615         int interactive = 0;
1616         int have_tty = 0;
1617         struct winsize ws;
1618         char *cp;
1619         const char *display;
1620
1621         /* Enable compression if requested. */
1622         if (options.compression) {
1623                 debug("Requesting compression at level %d.",
1624                     options.compression_level);
1625
1626                 if (options.compression_level < 1 ||
1627                     options.compression_level > 9)
1628                         fatal("Compression level must be from 1 (fast) to "
1629                             "9 (slow, best).");
1630
1631                 /* Send the request. */
1632                 packet_start(SSH_CMSG_REQUEST_COMPRESSION);
1633                 packet_put_int(options.compression_level);
1634                 packet_send();
1635                 packet_write_wait();
1636                 type = packet_read();
1637                 if (type == SSH_SMSG_SUCCESS)
1638                         packet_start_compression(options.compression_level);
1639                 else if (type == SSH_SMSG_FAILURE)
1640                         logit("Warning: Remote host refused compression.");
1641                 else
1642                         packet_disconnect("Protocol error waiting for "
1643                             "compression response.");
1644         }
1645         /* Allocate a pseudo tty if appropriate. */
1646         if (tty_flag) {
1647                 debug("Requesting pty.");
1648
1649                 /* Start the packet. */
1650                 packet_start(SSH_CMSG_REQUEST_PTY);
1651
1652                 /* Store TERM in the packet.  There is no limit on the
1653                    length of the string. */
1654                 cp = getenv("TERM");
1655                 if (!cp)
1656                         cp = "";
1657                 packet_put_cstring(cp);
1658
1659                 /* Store window size in the packet. */
1660                 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
1661                         memset(&ws, 0, sizeof(ws));
1662                 packet_put_int((u_int)ws.ws_row);
1663                 packet_put_int((u_int)ws.ws_col);
1664                 packet_put_int((u_int)ws.ws_xpixel);
1665                 packet_put_int((u_int)ws.ws_ypixel);
1666
1667                 /* Store tty modes in the packet. */
1668                 tty_make_modes(fileno(stdin), NULL);
1669
1670                 /* Send the packet, and wait for it to leave. */
1671                 packet_send();
1672                 packet_write_wait();
1673
1674                 /* Read response from the server. */
1675                 type = packet_read();
1676                 if (type == SSH_SMSG_SUCCESS) {
1677                         interactive = 1;
1678                         have_tty = 1;
1679                 } else if (type == SSH_SMSG_FAILURE)
1680                         logit("Warning: Remote host failed or refused to "
1681                             "allocate a pseudo tty.");
1682                 else
1683                         packet_disconnect("Protocol error waiting for pty "
1684                             "request response.");
1685         }
1686         /* Request X11 forwarding if enabled and DISPLAY is set. */
1687         display = getenv("DISPLAY");
1688         if (display == NULL && options.forward_x11)
1689                 debug("X11 forwarding requested but DISPLAY not set");
1690         if (options.forward_x11 && display != NULL) {
1691                 char *proto, *data;
1692                 /* Get reasonable local authentication information. */
1693                 client_x11_get_proto(display, options.xauth_location,
1694                     options.forward_x11_trusted,
1695                     options.forward_x11_timeout,
1696                     &proto, &data);
1697                 /* Request forwarding with authentication spoofing. */
1698                 debug("Requesting X11 forwarding with authentication "
1699                     "spoofing.");
1700                 x11_request_forwarding_with_spoofing(0, display, proto,
1701                     data, 0);
1702                 /* Read response from the server. */
1703                 type = packet_read();
1704                 if (type == SSH_SMSG_SUCCESS) {
1705                         interactive = 1;
1706                 } else if (type == SSH_SMSG_FAILURE) {
1707                         logit("Warning: Remote host denied X11 forwarding.");
1708                 } else {
1709                         packet_disconnect("Protocol error waiting for X11 "
1710                             "forwarding");
1711                 }
1712         }
1713         /* Tell the packet module whether this is an interactive session. */
1714         packet_set_interactive(interactive,
1715             options.ip_qos_interactive, options.ip_qos_bulk);
1716
1717         /* Request authentication agent forwarding if appropriate. */
1718         check_agent_present();
1719
1720         if (options.forward_agent) {
1721                 debug("Requesting authentication agent forwarding.");
1722                 auth_request_forwarding();
1723
1724                 /* Read response from the server. */
1725                 type = packet_read();
1726                 packet_check_eom();
1727                 if (type != SSH_SMSG_SUCCESS)
1728                         logit("Warning: Remote host denied authentication agent forwarding.");
1729         }
1730
1731         /* Initiate port forwardings. */
1732         ssh_init_stdio_forwarding();
1733         ssh_init_forwarding();
1734
1735         /* Execute a local command */
1736         if (options.local_command != NULL &&
1737             options.permit_local_command)
1738                 ssh_local_cmd(options.local_command);
1739
1740         /*
1741          * If requested and we are not interested in replies to remote
1742          * forwarding requests, then let ssh continue in the background.
1743          */
1744         if (fork_after_authentication_flag) {
1745                 if (options.exit_on_forward_failure &&
1746                     options.num_remote_forwards > 0) {
1747                         debug("deferring postauth fork until remote forward "
1748                             "confirmation received");
1749                 } else
1750                         fork_postauth();
1751         }
1752
1753         /*
1754          * If a command was specified on the command line, execute the
1755          * command now. Otherwise request the server to start a shell.
1756          */
1757         if (buffer_len(&command) > 0) {
1758                 int len = buffer_len(&command);
1759                 if (len > 900)
1760                         len = 900;
1761                 debug("Sending command: %.*s", len,
1762                     (u_char *)buffer_ptr(&command));
1763                 packet_start(SSH_CMSG_EXEC_CMD);
1764                 packet_put_string(buffer_ptr(&command), buffer_len(&command));
1765                 packet_send();
1766                 packet_write_wait();
1767         } else {
1768                 debug("Requesting shell.");
1769                 packet_start(SSH_CMSG_EXEC_SHELL);
1770                 packet_send();
1771                 packet_write_wait();
1772         }
1773
1774         /* Enter the interactive session. */
1775         return client_loop(have_tty, tty_flag ?
1776             options.escape_char : SSH_ESCAPECHAR_NONE, 0);
1777 }
1778
1779 /* request pty/x11/agent/tcpfwd/shell for channel */
1780 static void
1781 ssh_session2_setup(int id, int success, void *arg)
1782 {
1783         extern char **environ;
1784         const char *display;
1785         int interactive = tty_flag;
1786
1787         if (!success)
1788                 return; /* No need for error message, channels code sens one */
1789
1790         display = getenv("DISPLAY");
1791         if (display == NULL && options.forward_x11)
1792                 debug("X11 forwarding requested but DISPLAY not set");
1793         if (options.forward_x11 && display != NULL) {
1794                 char *proto, *data;
1795                 /* Get reasonable local authentication information. */
1796                 client_x11_get_proto(display, options.xauth_location,
1797                     options.forward_x11_trusted,
1798                     options.forward_x11_timeout, &proto, &data);
1799                 /* Request forwarding with authentication spoofing. */
1800                 debug("Requesting X11 forwarding with authentication "
1801                     "spoofing.");
1802                 x11_request_forwarding_with_spoofing(id, display, proto,
1803                     data, 1);
1804                 client_expect_confirm(id, "X11 forwarding", CONFIRM_WARN);
1805                 /* XXX exit_on_forward_failure */
1806                 interactive = 1;
1807         }
1808
1809         check_agent_present();
1810         if (options.forward_agent) {
1811                 debug("Requesting authentication agent forwarding.");
1812                 channel_request_start(id, "auth-agent-req@openssh.com", 0);
1813                 packet_send();
1814         }
1815
1816         /* Tell the packet module whether this is an interactive session. */
1817         packet_set_interactive(interactive,
1818             options.ip_qos_interactive, options.ip_qos_bulk);
1819
1820         client_session2_setup(id, tty_flag, subsystem_flag, getenv("TERM"),
1821             NULL, fileno(stdin), &command, environ);
1822 }
1823
1824 /* open new channel for a session */
1825 static int
1826 ssh_session2_open(void)
1827 {
1828         Channel *c;
1829         int window, packetmax, in, out, err;
1830
1831         if (stdin_null_flag) {
1832                 in = open(_PATH_DEVNULL, O_RDONLY);
1833         } else {
1834                 in = dup(STDIN_FILENO);
1835         }
1836         out = dup(STDOUT_FILENO);
1837         err = dup(STDERR_FILENO);
1838
1839         if (in < 0 || out < 0 || err < 0)
1840                 fatal("dup() in/out/err failed");
1841
1842         /* enable nonblocking unless tty */
1843         if (!isatty(in))
1844                 set_nonblock(in);
1845         if (!isatty(out))
1846                 set_nonblock(out);
1847         if (!isatty(err))
1848                 set_nonblock(err);
1849
1850         window = CHAN_SES_WINDOW_DEFAULT;
1851         packetmax = CHAN_SES_PACKET_DEFAULT;
1852         if (tty_flag) {
1853                 window >>= 1;
1854                 packetmax >>= 1;
1855         }
1856         c = channel_new(
1857             "session", SSH_CHANNEL_OPENING, in, out, err,
1858             window, packetmax, CHAN_EXTENDED_WRITE,
1859             "client-session", /*nonblock*/0);
1860
1861         debug3("ssh_session2_open: channel_new: %d", c->self);
1862
1863         channel_send_open(c->self);
1864         if (!no_shell_flag)
1865                 channel_register_open_confirm(c->self,
1866                     ssh_session2_setup, NULL);
1867
1868         return c->self;
1869 }
1870
1871 static int
1872 ssh_session2(void)
1873 {
1874         int id = -1;
1875
1876         /* XXX should be pre-session */
1877         if (!options.control_persist)
1878                 ssh_init_stdio_forwarding();
1879         ssh_init_forwarding();
1880
1881         /* Start listening for multiplex clients */
1882         muxserver_listen();
1883
1884         /*
1885          * If we are in control persist mode and have a working mux listen
1886          * socket, then prepare to background ourselves and have a foreground
1887          * client attach as a control slave.
1888          * NB. we must save copies of the flags that we override for
1889          * the backgrounding, since we defer attachment of the slave until
1890          * after the connection is fully established (in particular,
1891          * async rfwd replies have been received for ExitOnForwardFailure).
1892          */
1893         if (options.control_persist && muxserver_sock != -1) {
1894                 ostdin_null_flag = stdin_null_flag;
1895                 ono_shell_flag = no_shell_flag;
1896                 orequest_tty = options.request_tty;
1897                 otty_flag = tty_flag;
1898                 stdin_null_flag = 1;
1899                 no_shell_flag = 1;
1900                 tty_flag = 0;
1901                 if (!fork_after_authentication_flag)
1902                         need_controlpersist_detach = 1;
1903                 fork_after_authentication_flag = 1;
1904         }
1905         /*
1906          * ControlPersist mux listen socket setup failed, attempt the
1907          * stdio forward setup that we skipped earlier.
1908          */
1909         if (options.control_persist && muxserver_sock == -1)
1910                 ssh_init_stdio_forwarding();
1911
1912         if (!no_shell_flag || (datafellows & SSH_BUG_DUMMYCHAN))
1913                 id = ssh_session2_open();
1914         else {
1915                 packet_set_interactive(
1916                     options.control_master == SSHCTL_MASTER_NO,
1917                     options.ip_qos_interactive, options.ip_qos_bulk);
1918         }
1919
1920         /* If we don't expect to open a new session, then disallow it */
1921         if (options.control_master == SSHCTL_MASTER_NO &&
1922             (datafellows & SSH_NEW_OPENSSH)) {
1923                 debug("Requesting no-more-sessions@openssh.com");
1924                 packet_start(SSH2_MSG_GLOBAL_REQUEST);
1925                 packet_put_cstring("no-more-sessions@openssh.com");
1926                 packet_put_char(0);
1927                 packet_send();
1928         }
1929
1930         /* Execute a local command */
1931         if (options.local_command != NULL &&
1932             options.permit_local_command)
1933                 ssh_local_cmd(options.local_command);
1934
1935         /*
1936          * If requested and we are not interested in replies to remote
1937          * forwarding requests, then let ssh continue in the background.
1938          */
1939         if (fork_after_authentication_flag) {
1940                 if (options.exit_on_forward_failure &&
1941                     options.num_remote_forwards > 0) {
1942                         debug("deferring postauth fork until remote forward "
1943                             "confirmation received");
1944                 } else
1945                         fork_postauth();
1946         }
1947
1948         return client_loop(tty_flag, tty_flag ?
1949             options.escape_char : SSH_ESCAPECHAR_NONE, id);
1950 }
1951
1952 static void
1953 load_public_identity_files(void)
1954 {
1955         char *filename, *cp, thishost[NI_MAXHOST];
1956         char *pwdir = NULL, *pwname = NULL;
1957         int i = 0;
1958         Key *public;
1959         struct passwd *pw;
1960         u_int n_ids;
1961         char *identity_files[SSH_MAX_IDENTITY_FILES];
1962         Key *identity_keys[SSH_MAX_IDENTITY_FILES];
1963 #ifdef ENABLE_PKCS11
1964         Key **keys;
1965         int nkeys;
1966 #endif /* PKCS11 */
1967
1968         n_ids = 0;
1969         memset(identity_files, 0, sizeof(identity_files));
1970         memset(identity_keys, 0, sizeof(identity_keys));
1971
1972 #ifdef ENABLE_PKCS11
1973         if (options.pkcs11_provider != NULL &&
1974             options.num_identity_files < SSH_MAX_IDENTITY_FILES &&
1975             (pkcs11_init(!options.batch_mode) == 0) &&
1976             (nkeys = pkcs11_add_provider(options.pkcs11_provider, NULL,
1977             &keys)) > 0) {
1978                 for (i = 0; i < nkeys; i++) {
1979                         if (n_ids >= SSH_MAX_IDENTITY_FILES) {
1980                                 key_free(keys[i]);
1981                                 continue;
1982                         }
1983                         identity_keys[n_ids] = keys[i];
1984                         identity_files[n_ids] =
1985                             xstrdup(options.pkcs11_provider); /* XXX */
1986                         n_ids++;
1987                 }
1988                 free(keys);
1989         }
1990 #endif /* ENABLE_PKCS11 */
1991         if ((pw = getpwuid(original_real_uid)) == NULL)
1992                 fatal("load_public_identity_files: getpwuid failed");
1993         pwname = xstrdup(pw->pw_name);
1994         pwdir = xstrdup(pw->pw_dir);
1995         if (gethostname(thishost, sizeof(thishost)) == -1)
1996                 fatal("load_public_identity_files: gethostname: %s",
1997                     strerror(errno));
1998         for (i = 0; i < options.num_identity_files; i++) {
1999                 if (n_ids >= SSH_MAX_IDENTITY_FILES ||
2000                     strcasecmp(options.identity_files[i], "none") == 0) {
2001                         free(options.identity_files[i]);
2002                         continue;
2003                 }
2004                 cp = tilde_expand_filename(options.identity_files[i],
2005                     original_real_uid);
2006                 filename = percent_expand(cp, "d", pwdir,
2007                     "u", pwname, "l", thishost, "h", host,
2008                     "r", options.user, (char *)NULL);
2009                 free(cp);
2010                 public = key_load_public(filename, NULL);
2011                 debug("identity file %s type %d", filename,
2012                     public ? public->type : -1);
2013                 free(options.identity_files[i]);
2014                 identity_files[n_ids] = filename;
2015                 identity_keys[n_ids] = public;
2016
2017                 if (++n_ids >= SSH_MAX_IDENTITY_FILES)
2018                         continue;
2019
2020                 /* Try to add the certificate variant too */
2021                 xasprintf(&cp, "%s-cert", filename);
2022                 public = key_load_public(cp, NULL);
2023                 debug("identity file %s type %d", cp,
2024                     public ? public->type : -1);
2025                 if (public == NULL) {
2026                         free(cp);
2027                         continue;
2028                 }
2029                 if (!key_is_cert(public)) {
2030                         debug("%s: key %s type %s is not a certificate",
2031                             __func__, cp, key_type(public));
2032                         key_free(public);
2033                         free(cp);
2034                         continue;
2035                 }
2036                 identity_keys[n_ids] = public;
2037                 /* point to the original path, most likely the private key */
2038                 identity_files[n_ids] = xstrdup(filename);
2039                 n_ids++;
2040         }
2041         options.num_identity_files = n_ids;
2042         memcpy(options.identity_files, identity_files, sizeof(identity_files));
2043         memcpy(options.identity_keys, identity_keys, sizeof(identity_keys));
2044
2045         explicit_bzero(pwname, strlen(pwname));
2046         free(pwname);
2047         explicit_bzero(pwdir, strlen(pwdir));
2048         free(pwdir);
2049 }
2050
2051 static void
2052 main_sigchld_handler(int sig)
2053 {
2054         int save_errno = errno;
2055         pid_t pid;
2056         int status;
2057
2058         while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
2059             (pid < 0 && errno == EINTR))
2060                 ;
2061
2062         signal(sig, main_sigchld_handler);
2063         errno = save_errno;
2064 }